Index: linux-5.4.5-rt3/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
+++ linux-5.4.5-rt3/Documentation/RCU/Design/Expedited-Grace-Periods/Expedited-Grace-Periods.html
@@ -56,8 +56,8 @@ sections.
 RCU-preempt Expedited Grace Periods</a></h2>
 
 <p>
-<tt>CONFIG_PREEMPT=y</tt> kernels implement RCU-preempt.
-The overall flow of the handling of a given CPU by an RCU-preempt
+<tt>CONFIG_PREEMPT=y</tt> and <tt>CONFIG_PREEMPT_RT=y</tt> kernels implement
+RCU-preempt. The overall flow of the handling of a given CPU by an RCU-preempt
 expedited grace period is shown in the following diagram:
 
 <p><img src="ExpRCUFlow.svg" alt="ExpRCUFlow.svg" width="55%">
@@ -140,8 +140,8 @@ or offline, among other things.
 RCU-sched Expedited Grace Periods</a></h2>
 
 <p>
-<tt>CONFIG_PREEMPT=n</tt> kernels implement RCU-sched.
-The overall flow of the handling of a given CPU by an RCU-sched
+<tt>CONFIG_PREEMPT=n</tt> and <tt>CONFIG_PREEMPT_RT=n</tt> kernels implement
+RCU-sched. The overall flow of the handling of a given CPU by an RCU-sched
 expedited grace period is shown in the following diagram:
 
 <p><img src="ExpSchedFlow.svg" alt="ExpSchedFlow.svg" width="55%">
Index: linux-5.4.5-rt3/Documentation/RCU/Design/Requirements/Requirements.html
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/RCU/Design/Requirements/Requirements.html
+++ linux-5.4.5-rt3/Documentation/RCU/Design/Requirements/Requirements.html
@@ -106,7 +106,7 @@ big RCU read-side critical section.
 Production-quality implementations of <tt>rcu_read_lock()</tt> and
 <tt>rcu_read_unlock()</tt> are extremely lightweight, and in
 fact have exactly zero overhead in Linux kernels built for production
-use with <tt>CONFIG_PREEMPT=n</tt>.
+use with <tt>CONFIG_PREEMPTION=n</tt>.
 
 <p>
 This guarantee allows ordering to be enforced with extremely low
@@ -1499,7 +1499,7 @@ costs have plummeted.
 However, as I learned from Matt Mackall's
 <a href="http://elinux.org/Linux_Tiny-FAQ">bloatwatch</a>
 efforts, memory footprint is critically important on single-CPU systems with
-non-preemptible (<tt>CONFIG_PREEMPT=n</tt>) kernels, and thus
+non-preemptible (<tt>CONFIG_PREEMPTION=n</tt>) kernels, and thus
 <a href="https://lkml.kernel.org/g/20090113221724.GA15307@linux.vnet.ibm.com">tiny RCU</a>
 was born.
 Josh Triplett has since taken over the small-memory banner with his
@@ -1887,7 +1887,7 @@ constructs, there are limitations.
 <p>
 Implementations of RCU for which <tt>rcu_read_lock()</tt>
 and <tt>rcu_read_unlock()</tt> generate no code, such as
-Linux-kernel RCU when <tt>CONFIG_PREEMPT=n</tt>, can be
+Linux-kernel RCU when <tt>CONFIG_PREEMPTION=n</tt>, can be
 nested arbitrarily deeply.
 After all, there is no overhead.
 Except that if all these instances of <tt>rcu_read_lock()</tt>
@@ -2229,7 +2229,7 @@ be a no-op.
 <p>
 However, once the scheduler has spawned its first kthread, this early
 boot trick fails for <tt>synchronize_rcu()</tt> (as well as for
-<tt>synchronize_rcu_expedited()</tt>) in <tt>CONFIG_PREEMPT=y</tt>
+<tt>synchronize_rcu_expedited()</tt>) in <tt>CONFIG_PREEMPTION=y</tt>
 kernels.
 The reason is that an RCU read-side critical section might be preempted,
 which means that a subsequent <tt>synchronize_rcu()</tt> really does have
@@ -2568,7 +2568,7 @@ the following:
 
 <p>
 If the compiler did make this transformation in a
-<tt>CONFIG_PREEMPT=n</tt> kernel build, and if <tt>get_user()</tt> did
+<tt>CONFIG_PREEMPTION=n</tt> kernel build, and if <tt>get_user()</tt> did
 page fault, the result would be a quiescent state in the middle
 of an RCU read-side critical section.
 This misplaced quiescent state could result in line&nbsp;4 being
@@ -2906,7 +2906,7 @@ in conjunction with the
 The real-time-latency response requirements are such that the
 traditional approach of disabling preemption across RCU
 read-side critical sections is inappropriate.
-Kernels built with <tt>CONFIG_PREEMPT=y</tt> therefore
+Kernels built with <tt>CONFIG_PREEMPTION=y</tt> therefore
 use an RCU implementation that allows RCU read-side critical
 sections to be preempted.
 This requirement made its presence known after users made it
@@ -3064,7 +3064,7 @@ includes
 <tt>rcu_barrier_bh()</tt>, and
 <tt>rcu_read_lock_bh_held()</tt>.
 However, the update-side APIs are now simple wrappers for other RCU
-flavors, namely RCU-sched in CONFIG_PREEMPT=n kernels and RCU-preempt
+flavors, namely RCU-sched in CONFIG_PREEMPTION=n kernels and RCU-preempt
 otherwise.
 
 <h3><a name="Sched Flavor">Sched Flavor (Historical)</a></h3>
@@ -3088,12 +3088,12 @@ of an RCU read-side critical section can
 Therefore, <i>RCU-sched</i> was created, which follows &ldquo;classic&rdquo;
 RCU in that an RCU-sched grace period waits for for pre-existing
 interrupt and NMI handlers.
-In kernels built with <tt>CONFIG_PREEMPT=n</tt>, the RCU and RCU-sched
+In kernels built with <tt>CONFIG_PREEMPTION=n</tt>, the RCU and RCU-sched
 APIs have identical implementations, while kernels built with
-<tt>CONFIG_PREEMPT=y</tt> provide a separate implementation for each.
+<tt>CONFIG_PREEMPTION=y</tt> provide a separate implementation for each.
 
 <p>
-Note well that in <tt>CONFIG_PREEMPT=y</tt> kernels,
+Note well that in <tt>CONFIG_PREEMPTION=y</tt> kernels,
 <tt>rcu_read_lock_sched()</tt> and <tt>rcu_read_unlock_sched()</tt>
 disable and re-enable preemption, respectively.
 This means that if there was a preemption attempt during the
@@ -3302,12 +3302,12 @@ The tasks-RCU API is quite compact, cons
 <tt>call_rcu_tasks()</tt>,
 <tt>synchronize_rcu_tasks()</tt>, and
 <tt>rcu_barrier_tasks()</tt>.
-In <tt>CONFIG_PREEMPT=n</tt> kernels, trampolines cannot be preempted,
+In <tt>CONFIG_PREEMPTION=n</tt> kernels, trampolines cannot be preempted,
 so these APIs map to
 <tt>call_rcu()</tt>,
 <tt>synchronize_rcu()</tt>, and
 <tt>rcu_barrier()</tt>, respectively.
-In <tt>CONFIG_PREEMPT=y</tt> kernels, trampolines can be preempted,
+In <tt>CONFIG_PREEMPTION=y</tt> kernels, trampolines can be preempted,
 and these three APIs are therefore implemented by separate functions
 that check for voluntary context switches.
 
Index: linux-5.4.5-rt3/Documentation/RCU/checklist.txt
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/RCU/checklist.txt
+++ linux-5.4.5-rt3/Documentation/RCU/checklist.txt
@@ -210,8 +210,8 @@ over a rather long period of time, but i
 	the rest of the system.
 
 7.	As of v4.20, a given kernel implements only one RCU flavor,
-	which is RCU-sched for PREEMPT=n and RCU-preempt for PREEMPT=y.
-	If the updater uses call_rcu() or synchronize_rcu(),
+	which is RCU-sched for PREEMPTION=n and RCU-preempt for
+	PREEMPTION=y. If the updater uses call_rcu() or synchronize_rcu(),
 	then the corresponding readers my use rcu_read_lock() and
 	rcu_read_unlock(), rcu_read_lock_bh() and rcu_read_unlock_bh(),
 	or any pair of primitives that disables and re-enables preemption,
Index: linux-5.4.5-rt3/Documentation/RCU/rcubarrier.txt
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/RCU/rcubarrier.txt
+++ linux-5.4.5-rt3/Documentation/RCU/rcubarrier.txt
@@ -6,8 +6,8 @@ RCU (read-copy update) is a synchronizat
 of as a replacement for read-writer locking (among other things), but with
 very low-overhead readers that are immune to deadlock, priority inversion,
 and unbounded latency. RCU read-side critical sections are delimited
-by rcu_read_lock() and rcu_read_unlock(), which, in non-CONFIG_PREEMPT
-kernels, generate no code whatsoever.
+by rcu_read_lock() and rcu_read_unlock(), which, in
+non-CONFIG_PREEMPTION kernels, generate no code whatsoever.
 
 This means that RCU writers are unaware of the presence of concurrent
 readers, so that RCU updates to shared data must be undertaken quite
@@ -303,10 +303,10 @@ Answer: This cannot happen. The reason i
 	to smp_call_function() and further to smp_call_function_on_cpu(),
 	causing this latter to spin until the cross-CPU invocation of
 	rcu_barrier_func() has completed. This by itself would prevent
-	a grace period from completing on non-CONFIG_PREEMPT kernels,
+	a grace period from completing on non-CONFIG_PREEMPTION kernels,
 	since each CPU must undergo a context switch (or other quiescent
 	state) before the grace period can complete. However, this is
-	of no use in CONFIG_PREEMPT kernels.
+	of no use in CONFIG_PREEMPTION kernels.
 
 	Therefore, on_each_cpu() disables preemption across its call
 	to smp_call_function() and also across the local call to
Index: linux-5.4.5-rt3/Documentation/RCU/stallwarn.txt
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/RCU/stallwarn.txt
+++ linux-5.4.5-rt3/Documentation/RCU/stallwarn.txt
@@ -20,7 +20,7 @@ o	A CPU looping with preemption disabled
 
 o	A CPU looping with bottom halves disabled.
 
-o	For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel
+o	For !CONFIG_PREEMPTION kernels, a CPU looping anywhere in the kernel
 	without invoking schedule().  If the looping in the kernel is
 	really expected and desirable behavior, you might need to add
 	some calls to cond_resched().
@@ -39,7 +39,7 @@ o	Anything that prevents RCU's grace-per
 	result in the "rcu_.*kthread starved for" console-log message,
 	which will include additional debugging information.
 
-o	A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might
+o	A CPU-bound real-time task in a CONFIG_PREEMPTION kernel, which might
 	happen to preempt a low-priority task in the middle of an RCU
 	read-side critical section.   This is especially damaging if
 	that low-priority task is not permitted to run on any other CPU,
Index: linux-5.4.5-rt3/Documentation/RCU/whatisRCU.txt
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/RCU/whatisRCU.txt
+++ linux-5.4.5-rt3/Documentation/RCU/whatisRCU.txt
@@ -648,9 +648,10 @@ Quick Quiz #1:	Why is this argument naiv
 
 This section presents a "toy" RCU implementation that is based on
 "classic RCU".  It is also short on performance (but only for updates) and
-on features such as hotplug CPU and the ability to run in CONFIG_PREEMPT
-kernels.  The definitions of rcu_dereference() and rcu_assign_pointer()
-are the same as those shown in the preceding section, so they are omitted.
+on features such as hotplug CPU and the ability to run in
+CONFIG_PREEMPTION kernels. The definitions of rcu_dereference() and
+rcu_assign_pointer() are the same as those shown in the preceding
+section, so they are omitted.
 
 	void rcu_read_lock(void) { }
 
Index: linux-5.4.5-rt3/Documentation/printk-ringbuffer.txt
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/Documentation/printk-ringbuffer.txt
@@ -0,0 +1,377 @@
+struct printk_ringbuffer
+------------------------
+John Ogness <john.ogness@linutronix.de>
+
+Overview
+~~~~~~~~
+As the name suggests, this ring buffer was implemented specifically to serve
+the needs of the printk() infrastructure. The ring buffer itself is not
+specific to printk and could be used for other purposes. _However_, the
+requirements and semantics of printk are rather unique. If you intend to use
+this ring buffer for anything other than printk, you need to be very clear on
+its features, behavior, and pitfalls.
+
+Features
+^^^^^^^^
+The printk ring buffer has the following features:
+
+- single global buffer
+- resides in initialized data section (available at early boot)
+- lockless readers
+- supports multiple writers
+- supports multiple non-consuming readers
+- safe from any context (including NMI)
+- groups bytes into variable length blocks (referenced by entries)
+- entries tagged with sequence numbers
+
+Behavior
+^^^^^^^^
+Since the printk ring buffer readers are lockless, there exists no
+synchronization between readers and writers. Basically writers are the tasks
+in control and may overwrite any and all committed data at any time and from
+any context. For this reason readers can miss entries if they are overwritten
+before the reader was able to access the data. The reader API implementation
+is such that reader access to entries is atomic, so there is no risk of
+readers having to deal with partial or corrupt data. Also, entries are
+tagged with sequence numbers so readers can recognize if entries were missed.
+
+Writing to the ring buffer consists of 2 steps. First a writer must reserve
+an entry of desired size. After this step the writer has exclusive access
+to the memory region. Once the data has been written to memory, it needs to
+be committed to the ring buffer. After this step the entry has been inserted
+into the ring buffer and assigned an appropriate sequence number.
+
+Once committed, a writer must no longer access the data directly. This is
+because the data may have been overwritten and no longer exists. If a
+writer must access the data, it should either keep a private copy before
+committing the entry or use the reader API to gain access to the data.
+
+Because of how the data backend is implemented, entries that have been
+reserved but not yet committed act as barriers, preventing future writers
+from filling the ring buffer beyond the location of the reserved but not
+yet committed entry region. For this reason it is *important* that writers
+perform both reserve and commit as quickly as possible. Also, be aware that
+preemption and local interrupts are disabled and writing to the ring buffer
+is processor-reentrant locked during the reserve/commit window. Writers in
+NMI contexts can still preempt any other writers, but as long as these
+writers do not write a large amount of data with respect to the ring buffer
+size, this should not become an issue.
+
+API
+~~~
+
+Declaration
+^^^^^^^^^^^
+The printk ring buffer can be instantiated as a static structure:
+
+ /* declare a static struct printk_ringbuffer */
+ #define DECLARE_STATIC_PRINTKRB(name, szbits, cpulockptr)
+
+The value of szbits specifies the size of the ring buffer in bits. The
+cpulockptr field is a pointer to a prb_cpulock struct that is used to
+perform processor-reentrant spin locking for the writers. It is specified
+externally because it may be used for multiple ring buffers (or other
+code) to synchronize writers without risk of deadlock.
+
+Here is an example of a declaration of a printk ring buffer specifying a
+32KB (2^15) ring buffer:
+
+....
+DECLARE_STATIC_PRINTKRB_CPULOCK(rb_cpulock);
+DECLARE_STATIC_PRINTKRB(rb, 15, &rb_cpulock);
+....
+
+If writers will be using multiple ring buffers and the ordering of that usage
+is not clear, the same prb_cpulock should be used for both ring buffers.
+
+Writer API
+^^^^^^^^^^
+The writer API consists of 2 functions. The first is to reserve an entry in
+the ring buffer, the second is to commit that data to the ring buffer. The
+reserved entry information is stored within a provided `struct prb_handle`.
+
+ /* reserve an entry */
+ char *prb_reserve(struct prb_handle *h, struct printk_ringbuffer *rb,
+                   unsigned int size);
+
+ /* commit a reserved entry to the ring buffer */
+ void prb_commit(struct prb_handle *h);
+
+Here is an example of a function to write data to a ring buffer:
+
+....
+int write_data(struct printk_ringbuffer *rb, char *data, int size)
+{
+    struct prb_handle h;
+    char *buf;
+
+    buf = prb_reserve(&h, rb, size);
+    if (!buf)
+        return -1;
+    memcpy(buf, data, size);
+    prb_commit(&h);
+
+    return 0;
+}
+....
+
+Pitfalls
+++++++++
+Be aware that prb_reserve() can fail. A retry might be successful, but it
+depends entirely on whether or not the next part of the ring buffer to
+overwrite belongs to reserved but not yet committed entries of other writers.
+Writers can use the prb_inc_lost() function to allow readers to notice that a
+message was lost.
+
+Reader API
+^^^^^^^^^^
+The reader API utilizes a `struct prb_iterator` to track the reader's
+position in the ring buffer.
+
+ /* declare a pre-initialized static iterator for a ring buffer */
+ #define DECLARE_STATIC_PRINTKRB_ITER(name, rbaddr)
+
+ /* initialize iterator for a ring buffer (if static macro NOT used) */
+ void prb_iter_init(struct prb_iterator *iter,
+                    struct printk_ringbuffer *rb, u64 *seq);
+
+ /* make a deep copy of an iterator */
+ void prb_iter_copy(struct prb_iterator *dest,
+                    struct prb_iterator *src);
+
+ /* non-blocking, advance to next entry (and read the data) */
+ int prb_iter_next(struct prb_iterator *iter, char *buf,
+                   int size, u64 *seq);
+
+ /* blocking, advance to next entry (and read the data) */
+ int prb_iter_wait_next(struct prb_iterator *iter, char *buf,
+                        int size, u64 *seq);
+
+ /* position iterator at the entry seq */
+ int prb_iter_seek(struct prb_iterator *iter, u64 seq);
+
+ /* read data at current position */
+ int prb_iter_data(struct prb_iterator *iter, char *buf,
+                   int size, u64 *seq);
+
+Typically prb_iter_data() is not needed because the data can be retrieved
+directly with prb_iter_next().
+
+Here is an example of a non-blocking function that will read all the data in
+a ring buffer:
+
+....
+void read_all_data(struct printk_ringbuffer *rb, char *buf, int size)
+{
+    struct prb_iterator iter;
+    u64 prev_seq = 0;
+    u64 seq;
+    int ret;
+
+    prb_iter_init(&iter, rb, NULL);
+
+    for (;;) {
+        ret = prb_iter_next(&iter, buf, size, &seq);
+        if (ret > 0) {
+            if (seq != ++prev_seq) {
+                /* "seq - prev_seq" entries missed */
+                prev_seq = seq;
+            }
+            /* process buf here */
+        } else if (ret == 0) {
+            /* hit the end, done */
+            break;
+        } else if (ret < 0) {
+            /*
+             * iterator is invalid, a writer overtook us, reset the
+             * iterator and keep going, entries were missed
+             */
+            prb_iter_init(&iter, rb, NULL);
+        }
+    }
+}
+....
+
+Pitfalls
+++++++++
+The reader's iterator can become invalid at any time because the reader was
+overtaken by a writer. Typically the reader should reset the iterator back
+to the current oldest entry (which will be newer than the entry the reader
+was at) and continue, noting the number of entries that were missed.
+
+Utility API
+^^^^^^^^^^^
+Several functions are available as convenience for external code.
+
+ /* query the size of the data buffer */
+ int prb_buffer_size(struct printk_ringbuffer *rb);
+
+ /* skip a seq number to signify a lost record */
+ void prb_inc_lost(struct printk_ringbuffer *rb);
+
+ /* processor-reentrant spin lock */
+ void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store);
+
+ /* processor-reentrant spin unlock */
+ void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store);
+
+Pitfalls
+++++++++
+Although the value returned by prb_buffer_size() does represent an absolute
+upper bound, the amount of data that can be stored within the ring buffer
+is actually less because of the additional storage space of a header for each
+entry.
+
+The prb_lock() and prb_unlock() functions can be used to synchronize between
+ring buffer writers and other external activities. The function of a
+processor-reentrant spin lock is to disable preemption and local interrupts
+and synchronize against other processors. It does *not* protect against
+multiple contexts of a single processor, i.e NMI.
+
+Implementation
+~~~~~~~~~~~~~~
+This section describes several of the implementation concepts and details to
+help developers better understand the code.
+
+Entries
+^^^^^^^
+All ring buffer data is stored within a single static byte array. The reason
+for this is to ensure that any pointers to the data (past and present) will
+always point to valid memory. This is important because the lockless readers
+may be preempted for long periods of time and when they resume may be working
+with expired pointers.
+
+Entries are identified by start index and size. (The start index plus size
+is the start index of the next entry.) The start index is not simply an
+offset into the byte array, but rather a logical position (lpos) that maps
+directly to byte array offsets.
+
+For example, for a byte array of 1000, an entry may have have a start index
+of 100. Another entry may have a start index of 1100. And yet another 2100.
+All of these entry are pointing to the same memory region, but only the most
+recent entry is valid. The other entries are pointing to valid memory, but
+represent entries that have been overwritten.
+
+Note that due to overflowing, the most recent entry is not necessarily the one
+with the highest lpos value. Indeed, the printk ring buffer initializes its
+data such that an overflow happens relatively quickly in order to validate the
+handling of this situation. The implementation assumes that an lpos (unsigned
+long) will never completely wrap while a reader is preempted. If this were to
+become an issue, the seq number (which never wraps) could be used to increase
+the robustness of handling this situation.
+
+Buffer Wrapping
+^^^^^^^^^^^^^^^
+If an entry starts near the end of the byte array but would extend beyond it,
+a special terminating entry (size = -1) is inserted into the byte array and
+the real entry is placed at the beginning of the byte array. This can waste
+space at the end of the byte array, but simplifies the implementation by
+allowing writers to always work with contiguous buffers.
+
+Note that the size field is the first 4 bytes of the entry header. Also note
+that calc_next() always ensures that there are at least 4 bytes left at the
+end of the byte array to allow room for a terminating entry.
+
+Ring Buffer Pointers
+^^^^^^^^^^^^^^^^^^^^
+Three pointers (lpos values) are used to manage the ring buffer:
+
+ - _tail_: points to the oldest entry
+ - _head_: points to where the next new committed entry will be
+ - _reserve_: points to where the next new reserved entry will be
+
+These pointers always maintain a logical ordering:
+
+ tail <= head <= reserve
+
+The reserve pointer moves forward when a writer reserves a new entry. The
+head pointer moves forward when a writer commits a new entry.
+
+The reserve pointer cannot overwrite the tail pointer in a wrap situation. In
+such a situation, the tail pointer must be "pushed forward", thus
+invalidating that oldest entry. Readers identify if they are accessing a
+valid entry by ensuring their entry pointer is `>= tail && < head`.
+
+If the tail pointer is equal to the head pointer, it cannot be pushed and any
+reserve operation will fail. The only resolution is for writers to commit
+their reserved entries.
+
+Processor-Reentrant Locking
+^^^^^^^^^^^^^^^^^^^^^^^^^^^
+The purpose of the processor-reentrant locking is to limit the interruption
+scenarios of writers to 2 contexts. This allows for a simplified
+implementation where:
+
+- The reserve/commit window only exists on 1 processor at a time. A reserve
+  can never fail due to uncommitted entries of other processors.
+
+- When committing entries, it is trivial to handle the situation when
+  subsequent entries have already been committed, i.e. managing the head
+  pointer.
+
+Performance
+~~~~~~~~~~~
+Some basic tests were performed on a quad Intel(R) Xeon(R) CPU E5-2697 v4 at
+2.30GHz (36 cores / 72 threads). All tests involved writing a total of
+32,000,000 records at an average of 33 bytes each. Each writer was pinned to
+its own CPU and would write as fast as it could until a total of 32,000,000
+records were written. All tests involved 2 readers that were both pinned
+together to another CPU. Each reader would read as fast as it could and track
+how many of the 32,000,000 records it could read. All tests used a ring buffer
+of 16KB in size, which holds around 350 records (header + data for each
+entry).
+
+The only difference between the tests is the number of writers (and thus also
+the number of records per writer). As more writers are added, the time to
+write a record increases. This is because data pointers, modified via cmpxchg,
+and global data access in general become more contended.
+
+1 writer
+^^^^^^^^
+ runtime: 0m 18s
+ reader1: 16219900/32000000 (50%) records
+ reader2: 16141582/32000000 (50%) records
+
+2 writers
+^^^^^^^^^
+ runtime: 0m 32s
+ reader1: 16327957/32000000 (51%) records
+ reader2: 16313988/32000000 (50%) records
+
+4 writers
+^^^^^^^^^
+ runtime: 0m 42s
+ reader1: 16421642/32000000 (51%) records
+ reader2: 16417224/32000000 (51%) records
+
+8 writers
+^^^^^^^^^
+ runtime: 0m 43s
+ reader1: 16418300/32000000 (51%) records
+ reader2: 16432222/32000000 (51%) records
+
+16 writers
+^^^^^^^^^^
+ runtime: 0m 54s
+ reader1: 16539189/32000000 (51%) records
+ reader2: 16542711/32000000 (51%) records
+
+32 writers
+^^^^^^^^^^
+ runtime: 1m 13s
+ reader1: 16731808/32000000 (52%) records
+ reader2: 16735119/32000000 (52%) records
+
+Comments
+^^^^^^^^
+It is particularly interesting to compare/contrast the 1-writer and 32-writer
+tests. Despite the writing of the 32,000,000 records taking over 4 times
+longer, the readers (which perform no cmpxchg) were still unable to keep up.
+This shows that the memory contention between the increasing number of CPUs
+also has a dramatic effect on readers.
+
+It should also be noted that in all cases each reader was able to read >=50%
+of the records. This means that a single reader would have been able to keep
+up with the writer(s) in all cases, becoming slightly easier as more writers
+are added. This was the purpose of pinning 2 readers to 1 CPU: to observe how
+maximum reader performance changes.
Index: linux-5.4.5-rt3/Documentation/trace/ftrace-uses.rst
===================================================================
--- linux-5.4.5-rt3.orig/Documentation/trace/ftrace-uses.rst
+++ linux-5.4.5-rt3/Documentation/trace/ftrace-uses.rst
@@ -146,7 +146,7 @@ FTRACE_OPS_FL_RECURSION_SAFE
 	itself or any nested functions that those functions call.
 
 	If this flag is set, it is possible that the callback will also
-	be called with preemption enabled (when CONFIG_PREEMPT is set),
+	be called with preemption enabled (when CONFIG_PREEMPTION is set),
 	but this is not guaranteed.
 
 FTRACE_OPS_FL_IPMODIFY
Index: linux-5.4.5-rt3/arch/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/Kconfig
+++ linux-5.4.5-rt3/arch/Kconfig
@@ -31,6 +31,7 @@ config OPROFILE
 	tristate "OProfile system profiling"
 	depends on PROFILING
 	depends on HAVE_OPROFILE
+	depends on !PREEMPT_RT
 	select RING_BUFFER
 	select RING_BUFFER_ALLOW_SWAP
 	help
Index: linux-5.4.5-rt3/arch/alpha/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/alpha/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/alpha/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef _ALPHA_SPINLOCK_TYPES_H
 #define _ALPHA_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
Index: linux-5.4.5-rt3/arch/arc/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/arc/kernel/entry.S
+++ linux-5.4.5-rt3/arch/arc/kernel/entry.S
@@ -337,11 +337,11 @@ resume_user_mode_begin:
 resume_kernel_mode:
 
 	; Disable Interrupts from this point on
-	; CONFIG_PREEMPT: This is a must for preempt_schedule_irq()
-	; !CONFIG_PREEMPT: To ensure restore_regs is intr safe
+	; CONFIG_PREEMPTION: This is a must for preempt_schedule_irq()
+	; !CONFIG_PREEMPTION: To ensure restore_regs is intr safe
 	IRQ_DISABLE	r9
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 
 	; Can't preempt if preemption disabled
 	GET_CURR_THR_INFO_FROM_SP   r10
Index: linux-5.4.5-rt3/arch/arm/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/Kconfig
+++ linux-5.4.5-rt3/arch/arm/Kconfig
@@ -32,6 +32,7 @@ config ARM
 	select ARCH_OPTIONAL_KERNEL_RWX if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_OPTIONAL_KERNEL_RWX_DEFAULT if CPU_V7
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_RT
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU
@@ -64,7 +65,7 @@ config ARM
 	select HARDIRQS_SW_RESEND
 	select HAVE_ARCH_AUDITSYSCALL if AEABI && !OABI_COMPAT
 	select HAVE_ARCH_BITREVERSE if (CPU_32v7M || CPU_32v7) && !CPU_32v6
-	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU
+	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL && !CPU_ENDIAN_BE32 && MMU && !PREEMPT_RT
 	select HAVE_ARCH_KGDB if !CPU_ENDIAN_BE32 && MMU
 	select HAVE_ARCH_MMAP_RND_BITS if MMU
 	select HAVE_ARCH_SECCOMP_FILTER if AEABI && !OABI_COMPAT
@@ -103,6 +104,7 @@ config ARM
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select HAVE_RCU_TABLE_FREE if SMP && ARM_LPAE
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RSEQ
Index: linux-5.4.5-rt3/arch/arm/include/asm/irq.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/include/asm/irq.h
+++ linux-5.4.5-rt3/arch/arm/include/asm/irq.h
@@ -23,6 +23,8 @@
 #endif
 
 #ifndef __ASSEMBLY__
+#include <linux/cpumask.h>
+
 struct irqaction;
 struct pt_regs;
 
Index: linux-5.4.5-rt3/arch/arm/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/arm/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 #define TICKET_SHIFT	16
 
 typedef struct {
Index: linux-5.4.5-rt3/arch/arm/include/asm/switch_to.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/include/asm/switch_to.h
+++ linux-5.4.5-rt3/arch/arm/include/asm/switch_to.h
@@ -4,13 +4,20 @@
 
 #include <linux/thread_info.h>
 
+#if defined CONFIG_PREEMPT_RT && defined CONFIG_HIGHMEM
+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p);
+#else
+static inline void
+switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
+#endif
+
 /*
  * For v7 SMP cores running a preemptible kernel we may be pre-empted
  * during a TLB maintenance operation, so execute an inner-shareable dsb
  * to ensure that the maintenance completes in case we migrate to another
  * CPU.
  */
-#if defined(CONFIG_PREEMPT) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7)
+#if defined(CONFIG_PREEMPTION) && defined(CONFIG_SMP) && defined(CONFIG_CPU_V7)
 #define __complete_pending_tlbi()	dsb(ish)
 #else
 #define __complete_pending_tlbi()
@@ -26,6 +33,7 @@ extern struct task_struct *__switch_to(s
 #define switch_to(prev,next,last)					\
 do {									\
 	__complete_pending_tlbi();					\
+	switch_kmaps(prev, next);					\
 	last = __switch_to(prev,task_thread_info(prev), task_thread_info(next));	\
 } while (0)
 
Index: linux-5.4.5-rt3/arch/arm/include/asm/thread_info.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/include/asm/thread_info.h
+++ linux-5.4.5-rt3/arch/arm/include/asm/thread_info.h
@@ -46,6 +46,7 @@ struct cpu_context_save {
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
 	int			preempt_count;	/* 0 => preemptable, <0 => bug */
+	int			preempt_lazy_count; /* 0 => preemptable, <0 => bug */
 	mm_segment_t		addr_limit;	/* address limit */
 	struct task_struct	*task;		/* main task structure */
 	__u32			cpu;		/* cpu */
@@ -139,7 +140,8 @@ extern int vfp_restore_user_hwstate(stru
 #define TIF_SYSCALL_TRACE	4	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	5	/* syscall auditing active */
 #define TIF_SYSCALL_TRACEPOINT	6	/* syscall tracepoint instrumentation */
-#define TIF_SECCOMP		7	/* seccomp syscall filtering active */
+#define TIF_SECCOMP		8	/* seccomp syscall filtering active */
+#define TIF_NEED_RESCHED_LAZY	7
 
 #define TIF_NOHZ		12	/* in adaptive nohz mode */
 #define TIF_USING_IWMMXT	17
@@ -149,6 +151,7 @@ extern int vfp_restore_user_hwstate(stru
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_UPROBE		(1 << TIF_UPROBE)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
@@ -164,7 +167,8 @@ extern int vfp_restore_user_hwstate(stru
  * Change these and you break ASM code in entry-common.S
  */
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
-				 _TIF_NOTIFY_RESUME | _TIF_UPROBE)
+				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
+				 _TIF_NEED_RESCHED_LAZY)
 
 #endif /* __KERNEL__ */
 #endif /* __ASM_ARM_THREAD_INFO_H */
Index: linux-5.4.5-rt3/arch/arm/kernel/asm-offsets.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/kernel/asm-offsets.c
+++ linux-5.4.5-rt3/arch/arm/kernel/asm-offsets.c
@@ -53,6 +53,7 @@ int main(void)
   BLANK();
   DEFINE(TI_FLAGS,		offsetof(struct thread_info, flags));
   DEFINE(TI_PREEMPT,		offsetof(struct thread_info, preempt_count));
+  DEFINE(TI_PREEMPT_LAZY,	offsetof(struct thread_info, preempt_lazy_count));
   DEFINE(TI_ADDR_LIMIT,		offsetof(struct thread_info, addr_limit));
   DEFINE(TI_TASK,		offsetof(struct thread_info, task));
   DEFINE(TI_CPU,		offsetof(struct thread_info, cpu));
Index: linux-5.4.5-rt3/arch/arm/kernel/entry-armv.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/kernel/entry-armv.S
+++ linux-5.4.5-rt3/arch/arm/kernel/entry-armv.S
@@ -211,13 +211,20 @@ __irq_svc:
 	svc_entry
 	irq_handler
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	ldr	r8, [tsk, #TI_PREEMPT]		@ get preempt count
-	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
 	teq	r8, #0				@ if preempt count != 0
+	bne	1f				@ return from exeption
+	ldr	r0, [tsk, #TI_FLAGS]		@ get flags
+	tst	r0, #_TIF_NEED_RESCHED		@ if NEED_RESCHED is set
+	blne	svc_preempt			@ preempt!
+
+	ldr	r8, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
+	teq	r8, #0				@ if preempt lazy count != 0
 	movne	r0, #0				@ force flags to 0
-	tst	r0, #_TIF_NEED_RESCHED
+	tst	r0, #_TIF_NEED_RESCHED_LAZY
 	blne	svc_preempt
+1:
 #endif
 
 	svc_exit r5, irq = 1			@ return from exception
@@ -226,14 +233,20 @@ ENDPROC(__irq_svc)
 
 	.ltorg
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 svc_preempt:
 	mov	r8, lr
 1:	bl	preempt_schedule_irq		@ irq en/disable is done inside
 	ldr	r0, [tsk, #TI_FLAGS]		@ get new tasks TI_FLAGS
 	tst	r0, #_TIF_NEED_RESCHED
+	bne	1b
+	tst	r0, #_TIF_NEED_RESCHED_LAZY
 	reteq	r8				@ go again
-	b	1b
+	ldr	r0, [tsk, #TI_PREEMPT_LAZY]	@ get preempt lazy count
+	teq	r0, #0				@ if preempt lazy count != 0
+	beq	1b
+	ret	r8				@ go again
+
 #endif
 
 __und_fault:
Index: linux-5.4.5-rt3/arch/arm/kernel/entry-common.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/kernel/entry-common.S
+++ linux-5.4.5-rt3/arch/arm/kernel/entry-common.S
@@ -53,7 +53,9 @@ __ret_fast_syscall:
 	cmp	r2, #TASK_SIZE
 	blne	addr_limit_check_failed
 	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
-	tst	r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+	tst	r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP)
+	bne	fast_work_pending
+	tst	r1, #_TIF_SECCOMP
 	bne	fast_work_pending
 
 
@@ -90,8 +92,11 @@ __ret_fast_syscall:
 	cmp	r2, #TASK_SIZE
 	blne	addr_limit_check_failed
 	ldr	r1, [tsk, #TI_FLAGS]		@ re-check for syscall tracing
-	tst	r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK
+	tst	r1, #((_TIF_SYSCALL_WORK | _TIF_WORK_MASK) & ~_TIF_SECCOMP)
+	bne	do_slower_path
+	tst	r1, #_TIF_SECCOMP
 	beq	no_work_pending
+do_slower_path:
  UNWIND(.fnend		)
 ENDPROC(ret_fast_syscall)
 
Index: linux-5.4.5-rt3/arch/arm/kernel/signal.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/kernel/signal.c
+++ linux-5.4.5-rt3/arch/arm/kernel/signal.c
@@ -649,7 +649,8 @@ do_work_pending(struct pt_regs *regs, un
 	 */
 	trace_hardirqs_off();
 	do {
-		if (likely(thread_flags & _TIF_NEED_RESCHED)) {
+		if (likely(thread_flags & (_TIF_NEED_RESCHED |
+					   _TIF_NEED_RESCHED_LAZY))) {
 			schedule();
 		} else {
 			if (unlikely(!user_mode(regs)))
Index: linux-5.4.5-rt3/arch/arm/kernel/smp.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/kernel/smp.c
+++ linux-5.4.5-rt3/arch/arm/kernel/smp.c
@@ -682,11 +682,9 @@ void handle_IPI(int ipinr, struct pt_reg
 		break;
 
 	case IPI_CPU_BACKTRACE:
-		printk_nmi_enter();
 		irq_enter();
 		nmi_cpu_backtrace(regs);
 		irq_exit();
-		printk_nmi_exit();
 		break;
 
 	default:
Index: linux-5.4.5-rt3/arch/arm/kernel/traps.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/kernel/traps.c
+++ linux-5.4.5-rt3/arch/arm/kernel/traps.c
@@ -248,6 +248,8 @@ void show_stack(struct task_struct *tsk,
 
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
+#elif defined(CONFIG_PREEMPT_RT)
+#define S_PREEMPT " PREEMPT_RT"
 #else
 #define S_PREEMPT ""
 #endif
Index: linux-5.4.5-rt3/arch/arm/mm/cache-v7.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/mm/cache-v7.S
+++ linux-5.4.5-rt3/arch/arm/mm/cache-v7.S
@@ -135,13 +135,13 @@ flush_levels:
 	and	r1, r1, #7			@ mask of the bits for current cache only
 	cmp	r1, #2				@ see what cache we have at this level
 	blt	skip				@ skip if no cache, or just i-cache
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	save_and_disable_irqs_notrace r9	@ make cssr&csidr read atomic
 #endif
 	mcr	p15, 2, r10, c0, c0, 0		@ select current cache level in cssr
 	isb					@ isb to sych the new cssr&csidr
 	mrc	p15, 1, r1, c0, c0, 0		@ read the new csidr
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	restore_irqs_notrace r9
 #endif
 	and	r2, r1, #7			@ extract the length of the cache lines
Index: linux-5.4.5-rt3/arch/arm/mm/cache-v7m.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/mm/cache-v7m.S
+++ linux-5.4.5-rt3/arch/arm/mm/cache-v7m.S
@@ -183,13 +183,13 @@ flush_levels:
 	and	r1, r1, #7			@ mask of the bits for current cache only
 	cmp	r1, #2				@ see what cache we have at this level
 	blt	skip				@ skip if no cache, or just i-cache
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	save_and_disable_irqs_notrace r9	@ make cssr&csidr read atomic
 #endif
 	write_csselr r10, r1			@ set current cache level
 	isb					@ isb to sych the new cssr&csidr
 	read_ccsidr r1				@ read the new csidr
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	restore_irqs_notrace r9
 #endif
 	and	r2, r1, #7			@ extract the length of the cache lines
Index: linux-5.4.5-rt3/arch/arm/mm/fault.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/mm/fault.c
+++ linux-5.4.5-rt3/arch/arm/mm/fault.c
@@ -414,6 +414,9 @@ do_translation_fault(unsigned long addr,
 	if (addr < TASK_SIZE)
 		return do_page_fault(addr, fsr, regs);
 
+	if (interrupts_enabled(regs))
+		local_irq_enable();
+
 	if (user_mode(regs))
 		goto bad_area;
 
@@ -481,6 +484,9 @@ do_translation_fault(unsigned long addr,
 static int
 do_sect_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 {
+	if (interrupts_enabled(regs))
+		local_irq_enable();
+
 	do_bad_area(addr, fsr, regs);
 	return 0;
 }
Index: linux-5.4.5-rt3/arch/arm/mm/highmem.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm/mm/highmem.c
+++ linux-5.4.5-rt3/arch/arm/mm/highmem.c
@@ -31,6 +31,11 @@ static inline pte_t get_fixmap_pte(unsig
 	return *ptep;
 }
 
+static unsigned int fixmap_idx(int type)
+{
+	return FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+}
+
 void *kmap(struct page *page)
 {
 	might_sleep();
@@ -51,12 +56,13 @@ EXPORT_SYMBOL(kunmap);
 
 void *kmap_atomic(struct page *page)
 {
+	pte_t pte = mk_pte(page, kmap_prot);
 	unsigned int idx;
 	unsigned long vaddr;
 	void *kmap;
 	int type;
 
-	preempt_disable();
+	preempt_disable_nort();
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
@@ -76,7 +82,7 @@ void *kmap_atomic(struct page *page)
 
 	type = kmap_atomic_idx_push();
 
-	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+	idx = fixmap_idx(type);
 	vaddr = __fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	/*
@@ -90,7 +96,10 @@ void *kmap_atomic(struct page *page)
 	 * in place, so the contained TLB flush ensures the TLB is updated
 	 * with the new mapping.
 	 */
-	set_fixmap_pte(idx, mk_pte(page, kmap_prot));
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_fixmap_pte(idx, pte);
 
 	return (void *)vaddr;
 }
@@ -103,44 +112,75 @@ void __kunmap_atomic(void *kvaddr)
 
 	if (kvaddr >= (void *)FIXADDR_START) {
 		type = kmap_atomic_idx();
-		idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+		idx = fixmap_idx(type);
 
 		if (cache_is_vivt())
 			__cpuc_flush_dcache_area((void *)vaddr, PAGE_SIZE);
+#ifdef CONFIG_PREEMPT_RT
+		current->kmap_pte[type] = __pte(0);
+#endif
 #ifdef CONFIG_DEBUG_HIGHMEM
 		BUG_ON(vaddr != __fix_to_virt(idx));
-		set_fixmap_pte(idx, __pte(0));
 #else
 		(void) idx;  /* to kill a warning */
 #endif
+		set_fixmap_pte(idx, __pte(0));
 		kmap_atomic_idx_pop();
 	} else if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
 		/* this address was obtained through kmap_high_get() */
 		kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
 	}
 	pagefault_enable();
-	preempt_enable();
+	preempt_enable_nort();
 }
 EXPORT_SYMBOL(__kunmap_atomic);
 
 void *kmap_atomic_pfn(unsigned long pfn)
 {
+	pte_t pte = pfn_pte(pfn, kmap_prot);
 	unsigned long vaddr;
 	int idx, type;
 	struct page *page = pfn_to_page(pfn);
 
-	preempt_disable();
+	preempt_disable_nort();
 	pagefault_disable();
 	if (!PageHighMem(page))
 		return page_address(page);
 
 	type = kmap_atomic_idx_push();
-	idx = FIX_KMAP_BEGIN + type + KM_TYPE_NR * smp_processor_id();
+	idx = fixmap_idx(type);
 	vaddr = __fix_to_virt(idx);
 #ifdef CONFIG_DEBUG_HIGHMEM
 	BUG_ON(!pte_none(get_fixmap_pte(vaddr)));
 #endif
-	set_fixmap_pte(idx, pfn_pte(pfn, kmap_prot));
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_fixmap_pte(idx, pte);
 
 	return (void *)vaddr;
 }
+#if defined CONFIG_PREEMPT_RT
+void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
+{
+	int i;
+
+	/*
+	 * Clear @prev's kmap_atomic mappings
+	 */
+	for (i = 0; i < prev_p->kmap_idx; i++) {
+		int idx = fixmap_idx(i);
+
+		set_fixmap_pte(idx, __pte(0));
+	}
+	/*
+	 * Restore @next_p's kmap_atomic mappings
+	 */
+	for (i = 0; i < next_p->kmap_idx; i++) {
+		int idx = fixmap_idx(i);
+
+		if (!pte_none(next_p->kmap_pte[i]))
+			set_fixmap_pte(idx, next_p->kmap_pte[i]);
+	}
+}
+#endif
Index: linux-5.4.5-rt3/arch/arm64/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/Kconfig
+++ linux-5.4.5-rt3/arch/arm64/Kconfig
@@ -35,32 +35,32 @@ config ARM64
 	select ARCH_HAS_TEARDOWN_DMA_OPS if IOMMU_SUPPORT
 	select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
 	select ARCH_HAVE_NMI_SAFE_CMPXCHG
-	select ARCH_INLINE_READ_LOCK if !PREEMPT
-	select ARCH_INLINE_READ_LOCK_BH if !PREEMPT
-	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPT
-	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPT
-	select ARCH_INLINE_READ_UNLOCK if !PREEMPT
-	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPT
-	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPT
-	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPT
-	select ARCH_INLINE_WRITE_LOCK if !PREEMPT
-	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPT
-	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPT
-	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPT
-	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPT
-	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPT
-	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPT
-	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPT
-	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPT
-	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPT
-	select ARCH_INLINE_SPIN_LOCK if !PREEMPT
-	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPT
-	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPT
-	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPT
-	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPT
-	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPT
-	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPT
-	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPT
+	select ARCH_INLINE_READ_LOCK if !PREEMPTION
+	select ARCH_INLINE_READ_LOCK_BH if !PREEMPTION
+	select ARCH_INLINE_READ_LOCK_IRQ if !PREEMPTION
+	select ARCH_INLINE_READ_LOCK_IRQSAVE if !PREEMPTION
+	select ARCH_INLINE_READ_UNLOCK if !PREEMPTION
+	select ARCH_INLINE_READ_UNLOCK_BH if !PREEMPTION
+	select ARCH_INLINE_READ_UNLOCK_IRQ if !PREEMPTION
+	select ARCH_INLINE_READ_UNLOCK_IRQRESTORE if !PREEMPTION
+	select ARCH_INLINE_WRITE_LOCK if !PREEMPTION
+	select ARCH_INLINE_WRITE_LOCK_BH if !PREEMPTION
+	select ARCH_INLINE_WRITE_LOCK_IRQ if !PREEMPTION
+	select ARCH_INLINE_WRITE_LOCK_IRQSAVE if !PREEMPTION
+	select ARCH_INLINE_WRITE_UNLOCK if !PREEMPTION
+	select ARCH_INLINE_WRITE_UNLOCK_BH if !PREEMPTION
+	select ARCH_INLINE_WRITE_UNLOCK_IRQ if !PREEMPTION
+	select ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE if !PREEMPTION
+	select ARCH_INLINE_SPIN_TRYLOCK if !PREEMPTION
+	select ARCH_INLINE_SPIN_TRYLOCK_BH if !PREEMPTION
+	select ARCH_INLINE_SPIN_LOCK if !PREEMPTION
+	select ARCH_INLINE_SPIN_LOCK_BH if !PREEMPTION
+	select ARCH_INLINE_SPIN_LOCK_IRQ if !PREEMPTION
+	select ARCH_INLINE_SPIN_LOCK_IRQSAVE if !PREEMPTION
+	select ARCH_INLINE_SPIN_UNLOCK if !PREEMPTION
+	select ARCH_INLINE_SPIN_UNLOCK_BH if !PREEMPTION
+	select ARCH_INLINE_SPIN_UNLOCK_IRQ if !PREEMPTION
+	select ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE if !PREEMPTION
 	select ARCH_KEEP_MEMBLOCK
 	select ARCH_USE_CMPXCHG_LOCKREF
 	select ARCH_USE_QUEUED_RWLOCKS
@@ -69,6 +69,7 @@ config ARM64
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_INT128 if GCC_VERSION >= 50000 || CC_IS_CLANG
 	select ARCH_SUPPORTS_NUMA_BALANCING
+	select ARCH_SUPPORTS_RT
 	select ARCH_WANT_COMPAT_IPC_PARSE_VERSION if COMPAT
 	select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT
 	select ARCH_WANT_FRAME_POINTERS
@@ -159,6 +160,7 @@ config ARM64
 	select HAVE_PERF_EVENTS
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_FUNCTION_ARG_ACCESS_API
 	select HAVE_RCU_TABLE_FREE
Index: linux-5.4.5-rt3/arch/arm64/crypto/sha256-glue.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/crypto/sha256-glue.c
+++ linux-5.4.5-rt3/arch/arm64/crypto/sha256-glue.c
@@ -97,7 +97,7 @@ static int sha256_update_neon(struct sha
 		 * input when running on a preemptible kernel, but process the
 		 * data block by block instead.
 		 */
-		if (IS_ENABLED(CONFIG_PREEMPT) &&
+		if (IS_ENABLED(CONFIG_PREEMPTION) &&
 		    chunk + sctx->count % SHA256_BLOCK_SIZE > SHA256_BLOCK_SIZE)
 			chunk = SHA256_BLOCK_SIZE -
 				sctx->count % SHA256_BLOCK_SIZE;
Index: linux-5.4.5-rt3/arch/arm64/include/asm/assembler.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/include/asm/assembler.h
+++ linux-5.4.5-rt3/arch/arm64/include/asm/assembler.h
@@ -699,8 +699,8 @@ USER(\label, ic	ivau, \tmp2)			// invali
  * where <label> is optional, and marks the point where execution will resume
  * after a yield has been performed. If omitted, execution resumes right after
  * the endif_yield_neon invocation. Note that the entire sequence, including
- * the provided patchup code, will be omitted from the image if CONFIG_PREEMPT
- * is not defined.
+ * the provided patchup code, will be omitted from the image if
+ * CONFIG_PREEMPTION is not defined.
  *
  * As a convenience, in the case where no patchup code is required, the above
  * sequence may be abbreviated to
@@ -728,7 +728,7 @@ USER(\label, ic	ivau, \tmp2)			// invali
 	.endm
 
 	.macro		if_will_cond_yield_neon
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	get_current_task	x0
 	ldr		x0, [x0, #TSK_TI_PREEMPT]
 	sub		x0, x0, #PREEMPT_DISABLE_OFFSET
Index: linux-5.4.5-rt3/arch/arm64/include/asm/kvm_mmu.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/include/asm/kvm_mmu.h
+++ linux-5.4.5-rt3/arch/arm64/include/asm/kvm_mmu.h
@@ -91,6 +91,7 @@ alternative_cb_end
 
 void kvm_update_va_mask(struct alt_instr *alt,
 			__le32 *origptr, __le32 *updptr, int nr_inst);
+void kvm_compute_layout(void);
 
 static inline unsigned long __kern_hyp_va(unsigned long v)
 {
Index: linux-5.4.5-rt3/arch/arm64/include/asm/preempt.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/include/asm/preempt.h
+++ linux-5.4.5-rt3/arch/arm64/include/asm/preempt.h
@@ -70,20 +70,43 @@ static inline bool __preempt_count_dec_a
 	 * interrupt occurring between the non-atomic READ_ONCE/WRITE_ONCE
 	 * pair.
 	 */
-	return !pc || !READ_ONCE(ti->preempt_count);
+	if (!pc || !READ_ONCE(ti->preempt_count))
+		return true;
+#ifdef CONFIG_PREEMPT_LAZY
+	if ((pc & ~PREEMPT_NEED_RESCHED))
+		return false;
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
+	return false;
+#endif
 }
 
 static inline bool should_resched(int preempt_offset)
 {
+#ifdef CONFIG_PREEMPT_LAZY
+	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
+	if (pc == preempt_offset)
+		return true;
+
+	if ((pc & ~PREEMPT_NEED_RESCHED) != preempt_offset)
+		return false;
+
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
 	u64 pc = READ_ONCE(current_thread_info()->preempt_count);
 	return pc == preempt_offset;
+#endif
 }
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 void preempt_schedule(void);
 #define __preempt_schedule() preempt_schedule()
 void preempt_schedule_notrace(void);
 #define __preempt_schedule_notrace() preempt_schedule_notrace()
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 #endif /* __ASM_PREEMPT_H */
Index: linux-5.4.5-rt3/arch/arm64/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/arm64/include/asm/spinlock_types.h
@@ -5,10 +5,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H)
-# error "please don't include this file directly"
-#endif
-
 #include <asm-generic/qspinlock_types.h>
 #include <asm-generic/qrwlock_types.h>
 
Index: linux-5.4.5-rt3/arch/arm64/include/asm/thread_info.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/include/asm/thread_info.h
+++ linux-5.4.5-rt3/arch/arm64/include/asm/thread_info.h
@@ -29,6 +29,7 @@ struct thread_info {
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
 	u64			ttbr0;		/* saved TTBR0_EL1 */
 #endif
+	int			preempt_lazy_count;	/* 0 => preemptable, <0 => bug */
 	union {
 		u64		preempt_count;	/* 0 => preemptible, <0 => bug */
 		struct {
@@ -63,6 +64,7 @@ void arch_release_task_struct(struct tas
 #define TIF_FOREIGN_FPSTATE	3	/* CPU's FP state is not current's */
 #define TIF_UPROBE		4	/* uprobe breakpoint or singlestep */
 #define TIF_FSCHECK		5	/* Check FS is USER_DS on return */
+#define TIF_NEED_RESCHED_LAZY	6
 #define TIF_NOHZ		7
 #define TIF_SYSCALL_TRACE	8	/* syscall trace active */
 #define TIF_SYSCALL_AUDIT	9	/* syscall auditing */
@@ -83,6 +85,7 @@ void arch_release_task_struct(struct tas
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
 #define _TIF_NOTIFY_RESUME	(1 << TIF_NOTIFY_RESUME)
 #define _TIF_FOREIGN_FPSTATE	(1 << TIF_FOREIGN_FPSTATE)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_NOHZ		(1 << TIF_NOHZ)
 #define _TIF_SYSCALL_TRACE	(1 << TIF_SYSCALL_TRACE)
 #define _TIF_SYSCALL_AUDIT	(1 << TIF_SYSCALL_AUDIT)
@@ -96,8 +99,9 @@ void arch_release_task_struct(struct tas
 
 #define _TIF_WORK_MASK		(_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
 				 _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
-				 _TIF_UPROBE | _TIF_FSCHECK)
+				 _TIF_UPROBE | _TIF_FSCHECK | _TIF_NEED_RESCHED_LAZY)
 
+#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
 #define _TIF_SYSCALL_WORK	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
 				 _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
 				 _TIF_NOHZ | _TIF_SYSCALL_EMU)
Index: linux-5.4.5-rt3/arch/arm64/kernel/asm-offsets.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kernel/asm-offsets.c
+++ linux-5.4.5-rt3/arch/arm64/kernel/asm-offsets.c
@@ -30,6 +30,7 @@ int main(void)
   BLANK();
   DEFINE(TSK_TI_FLAGS,		offsetof(struct task_struct, thread_info.flags));
   DEFINE(TSK_TI_PREEMPT,	offsetof(struct task_struct, thread_info.preempt_count));
+  DEFINE(TSK_TI_PREEMPT_LAZY,	offsetof(struct task_struct, thread_info.preempt_lazy_count));
   DEFINE(TSK_TI_ADDR_LIMIT,	offsetof(struct task_struct, thread_info.addr_limit));
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
   DEFINE(TSK_TI_TTBR0,		offsetof(struct task_struct, thread_info.ttbr0));
Index: linux-5.4.5-rt3/arch/arm64/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kernel/entry.S
+++ linux-5.4.5-rt3/arch/arm64/kernel/entry.S
@@ -669,7 +669,7 @@ el1_irq:
 
 	irq_handler
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	ldr	x24, [tsk, #TSK_TI_PREEMPT]	// get preempt count
 alternative_if ARM64_HAS_IRQ_PRIO_MASKING
 	/*
@@ -679,9 +679,18 @@ alternative_if ARM64_HAS_IRQ_PRIO_MASKIN
 	mrs	x0, daif
 	orr	x24, x24, x0
 alternative_else_nop_endif
-	cbnz	x24, 1f				// preempt count != 0 || NMI return path
-	bl	arm64_preempt_schedule_irq	// irq en/disable is done inside
+
+	cbz	x24, 1f					// (need_resched + count) == 0
+	cbnz	w24, 2f					// count != 0
+
+	ldr	w24, [tsk, #TSK_TI_PREEMPT_LAZY]	// get preempt lazy count
+	cbnz	w24, 2f					// preempt lazy count != 0
+
+	ldr	x0, [tsk, #TSK_TI_FLAGS]		// get flags
+	tbz	x0, #TIF_NEED_RESCHED_LAZY, 2f		// needs rescheduling?
 1:
+	bl	arm64_preempt_schedule_irq		// irq en/disable is done inside
+2:
 #endif
 
 #ifdef CONFIG_ARM64_PSEUDO_NMI
Index: linux-5.4.5-rt3/arch/arm64/kernel/fpsimd.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kernel/fpsimd.c
+++ linux-5.4.5-rt3/arch/arm64/kernel/fpsimd.c
@@ -213,6 +213,16 @@ static void sve_free(struct task_struct
 	__sve_free(task);
 }
 
+static void *sve_free_atomic(struct task_struct *task)
+{
+	void *sve_state = task->thread.sve_state;
+
+	WARN_ON(test_tsk_thread_flag(task, TIF_SVE));
+
+	task->thread.sve_state = NULL;
+	return sve_state;
+}
+
 /*
  * TIF_SVE controls whether a task can use SVE without trapping while
  * in userspace, and also the way a task's FPSIMD/SVE state is stored
@@ -1008,6 +1018,7 @@ void fpsimd_thread_switch(struct task_st
 void fpsimd_flush_thread(void)
 {
 	int vl, supported_vl;
+	void *mem = NULL;
 
 	if (!system_supports_fpsimd())
 		return;
@@ -1020,7 +1031,7 @@ void fpsimd_flush_thread(void)
 
 	if (system_supports_sve()) {
 		clear_thread_flag(TIF_SVE);
-		sve_free(current);
+		mem = sve_free_atomic(current);
 
 		/*
 		 * Reset the task vector length as required.
@@ -1054,6 +1065,7 @@ void fpsimd_flush_thread(void)
 	}
 
 	put_cpu_fpsimd_context();
+	kfree(mem);
 }
 
 /*
Index: linux-5.4.5-rt3/arch/arm64/kernel/signal.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kernel/signal.c
+++ linux-5.4.5-rt3/arch/arm64/kernel/signal.c
@@ -910,7 +910,7 @@ asmlinkage void do_notify_resume(struct
 		/* Check valid user FS if needed */
 		addr_limit_user_check();
 
-		if (thread_flags & _TIF_NEED_RESCHED) {
+		if (thread_flags & _TIF_NEED_RESCHED_MASK) {
 			/* Unmask Debug and SError for the next task */
 			local_daif_restore(DAIF_PROCCTX_NOIRQ);
 
Index: linux-5.4.5-rt3/arch/arm64/kernel/smp.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kernel/smp.c
+++ linux-5.4.5-rt3/arch/arm64/kernel/smp.c
@@ -31,6 +31,7 @@
 #include <linux/of.h>
 #include <linux/irq_work.h>
 #include <linux/kexec.h>
+#include <linux/kvm_host.h>
 
 #include <asm/alternative.h>
 #include <asm/atomic.h>
@@ -39,6 +40,7 @@
 #include <asm/cputype.h>
 #include <asm/cpu_ops.h>
 #include <asm/daifflags.h>
+#include <asm/kvm_mmu.h>
 #include <asm/mmu_context.h>
 #include <asm/numa.h>
 #include <asm/pgtable.h>
@@ -408,6 +410,8 @@ static void __init hyp_mode_check(void)
 			   "CPU: CPUs started in inconsistent modes");
 	else
 		pr_info("CPU: All CPU(s) started at EL1\n");
+	if (IS_ENABLED(CONFIG_KVM_ARM_HOST))
+		kvm_compute_layout();
 }
 
 void __init smp_cpus_done(unsigned int max_cpus)
Index: linux-5.4.5-rt3/arch/arm64/kernel/traps.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kernel/traps.c
+++ linux-5.4.5-rt3/arch/arm64/kernel/traps.c
@@ -143,9 +143,12 @@ void show_stack(struct task_struct *tsk,
 
 #ifdef CONFIG_PREEMPT
 #define S_PREEMPT " PREEMPT"
+#elif defined(CONFIG_PREEMPT_RT)
+#define S_PREEMPT " PREEMPT_RT"
 #else
 #define S_PREEMPT ""
 #endif
+
 #define S_SMP " SMP"
 
 static int __die(const char *str, int err, struct pt_regs *regs)
Index: linux-5.4.5-rt3/arch/arm64/kvm/va_layout.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/arm64/kvm/va_layout.c
+++ linux-5.4.5-rt3/arch/arm64/kvm/va_layout.c
@@ -22,7 +22,7 @@ static u8 tag_lsb;
 static u64 tag_val;
 static u64 va_mask;
 
-static void compute_layout(void)
+__init void kvm_compute_layout(void)
 {
 	phys_addr_t idmap_addr = __pa_symbol(__hyp_idmap_text_start);
 	u64 hyp_va_msb;
@@ -110,9 +110,6 @@ void __init kvm_update_va_mask(struct al
 
 	BUG_ON(nr_inst != 5);
 
-	if (!has_vhe() && !va_mask)
-		compute_layout();
-
 	for (i = 0; i < nr_inst; i++) {
 		u32 rd, rn, insn, oinsn;
 
@@ -156,9 +153,6 @@ void kvm_patch_vector_branch(struct alt_
 		return;
 	}
 
-	if (!va_mask)
-		compute_layout();
-
 	/*
 	 * Compute HYP VA by using the same computation as kern_hyp_va()
 	 */
Index: linux-5.4.5-rt3/arch/c6x/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/c6x/kernel/entry.S
+++ linux-5.4.5-rt3/arch/c6x/kernel/entry.S
@@ -18,7 +18,7 @@
 #define DP	B14
 #define SP	B15
 
-#ifndef CONFIG_PREEMPT
+#ifndef CONFIG_PREEMPTION
 #define resume_kernel restore_all
 #endif
 
@@ -287,7 +287,7 @@ work_notifysig:
 	;; is a little bit different
 	;;
 ENTRY(ret_from_exception)
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	MASK_INT B2
 #endif
 
@@ -557,7 +557,7 @@ ENDPROC(_nmi_handler)
 	;;
 	;; Jump to schedule() then return to ret_from_isr
 	;;
-#ifdef	CONFIG_PREEMPT
+#ifdef	CONFIG_PREEMPTION
 resume_kernel:
 	GET_THREAD_INFO A12
 	LDW	.D1T1	*+A12(THREAD_INFO_PREEMPT_COUNT),A1
@@ -582,7 +582,7 @@ preempt_schedule:
 	B	.S2	preempt_schedule_irq
 #endif
 	ADDKPC	.S2	preempt_schedule,B3,4
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 ENTRY(enable_exception)
 	DINT
Index: linux-5.4.5-rt3/arch/csky/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/csky/kernel/entry.S
+++ linux-5.4.5-rt3/arch/csky/kernel/entry.S
@@ -277,7 +277,7 @@ ENTRY(csky_irq)
 	zero_fp
 	psrset	ee
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	mov	r9, sp			/* Get current stack  pointer */
 	bmaski	r10, THREAD_SHIFT
 	andn	r9, r10			/* Get thread_info */
@@ -294,7 +294,7 @@ ENTRY(csky_irq)
 	mov	a0, sp
 	jbsr	csky_do_IRQ
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	subi	r12, 1
 	stw	r12, (r9, TINFO_PREEMPT)
 	cmpnei	r12, 0
Index: linux-5.4.5-rt3/arch/h8300/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/h8300/kernel/entry.S
+++ linux-5.4.5-rt3/arch/h8300/kernel/entry.S
@@ -284,12 +284,12 @@ badsys:
 	mov.l	er0,@(LER0:16,sp)
 	bra	resume_userspace
 
-#if !defined(CONFIG_PREEMPT)
+#if !defined(CONFIG_PREEMPTION)
 #define resume_kernel restore_all
 #endif
 
 ret_from_exception:
-#if defined(CONFIG_PREEMPT)
+#if defined(CONFIG_PREEMPTION)
 	orc	#0xc0,ccr
 #endif
 ret_from_interrupt:
@@ -319,7 +319,7 @@ work_resched:
 restore_all:
 	RESTORE_ALL			/* Does RTE */
 
-#if defined(CONFIG_PREEMPT)
+#if defined(CONFIG_PREEMPTION)
 resume_kernel:
 	mov.l	@(TI_PRE_COUNT:16,er4),er0
 	bne	restore_all:8
Index: linux-5.4.5-rt3/arch/hexagon/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/hexagon/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/hexagon/include/asm/spinlock_types.h
@@ -8,10 +8,6 @@
 #ifndef _ASM_SPINLOCK_TYPES_H
 #define _ASM_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
Index: linux-5.4.5-rt3/arch/hexagon/kernel/vm_entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/hexagon/kernel/vm_entry.S
+++ linux-5.4.5-rt3/arch/hexagon/kernel/vm_entry.S
@@ -265,12 +265,12 @@ event_dispatch:
 	 * should be in the designated register (usually R19)
 	 *
 	 * If we were in kernel mode, we don't need to check scheduler
-	 * or signals if CONFIG_PREEMPT is not set.  If set, then it has
+	 * or signals if CONFIG_PREEMPTION is not set.  If set, then it has
 	 * to jump to a need_resched kind of block.
-	 * BTW, CONFIG_PREEMPT is not supported yet.
+	 * BTW, CONFIG_PREEMPTION is not supported yet.
 	 */
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	R0 = #VM_INT_DISABLE
 	trap1(#HVM_TRAP1_VMSETIE)
 #endif
Index: linux-5.4.5-rt3/arch/ia64/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/ia64/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/ia64/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef _ASM_IA64_SPINLOCK_TYPES_H
 #define _ASM_IA64_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
Index: linux-5.4.5-rt3/arch/ia64/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/ia64/kernel/entry.S
+++ linux-5.4.5-rt3/arch/ia64/kernel/entry.S
@@ -670,12 +670,12 @@ GLOBAL_ENTRY(ia64_leave_syscall)
 	 *
 	 * p6 controls whether current_thread_info()->flags needs to be check for
 	 * extra work.  We always check for extra work when returning to user-level.
-	 * With CONFIG_PREEMPT, we also check for extra work when the preempt_count
+	 * With CONFIG_PREEMPTION, we also check for extra work when the preempt_count
 	 * is 0.  After extra work processing has been completed, execution
 	 * resumes at ia64_work_processed_syscall with p6 set to 1 if the extra-work-check
 	 * needs to be redone.
 	 */
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	RSM_PSR_I(p0, r2, r18)			// disable interrupts
 	cmp.eq pLvSys,p0=r0,r0			// pLvSys=1: leave from syscall
 (pKStk) adds r20=TI_PRE_COUNT+IA64_TASK_SIZE,r13
@@ -685,7 +685,7 @@ GLOBAL_ENTRY(ia64_leave_syscall)
 (pUStk)	mov r21=0			// r21 <- 0
 	;;
 	cmp.eq p6,p0=r21,r0		// p6 <- pUStk || (preempt_count == 0)
-#else /* !CONFIG_PREEMPT */
+#else /* !CONFIG_PREEMPTION */
 	RSM_PSR_I(pUStk, r2, r18)
 	cmp.eq pLvSys,p0=r0,r0		// pLvSys=1: leave from syscall
 (pUStk)	cmp.eq.unc p6,p0=r0,r0		// p6 <- pUStk
@@ -814,12 +814,12 @@ GLOBAL_ENTRY(ia64_leave_kernel)
 	 *
 	 * p6 controls whether current_thread_info()->flags needs to be check for
 	 * extra work.  We always check for extra work when returning to user-level.
-	 * With CONFIG_PREEMPT, we also check for extra work when the preempt_count
+	 * With CONFIG_PREEMPTION, we also check for extra work when the preempt_count
 	 * is 0.  After extra work processing has been completed, execution
 	 * resumes at .work_processed_syscall with p6 set to 1 if the extra-work-check
 	 * needs to be redone.
 	 */
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	RSM_PSR_I(p0, r17, r31)			// disable interrupts
 	cmp.eq p0,pLvSys=r0,r0			// pLvSys=0: leave from kernel
 (pKStk)	adds r20=TI_PRE_COUNT+IA64_TASK_SIZE,r13
@@ -1120,7 +1120,7 @@ skip_rbs_switch:
 
 	/*
 	 * On entry:
-	 *	r20 = &current->thread_info->pre_count (if CONFIG_PREEMPT)
+	 *	r20 = &current->thread_info->pre_count (if CONFIG_PREEMPTION)
 	 *	r31 = current->thread_info->flags
 	 * On exit:
 	 *	p6 = TRUE if work-pending-check needs to be redone
Index: linux-5.4.5-rt3/arch/ia64/kernel/kprobes.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/ia64/kernel/kprobes.c
+++ linux-5.4.5-rt3/arch/ia64/kernel/kprobes.c
@@ -841,7 +841,7 @@ static int __kprobes pre_kprobes_handler
 		return 1;
 	}
 
-#if !defined(CONFIG_PREEMPT)
+#if !defined(CONFIG_PREEMPTION)
 	if (p->ainsn.inst_flag == INST_FLAG_BOOSTABLE && !p->post_handler) {
 		/* Boost up -- we can execute copied instructions directly */
 		ia64_psr(regs)->ri = p->ainsn.slot;
Index: linux-5.4.5-rt3/arch/m68k/coldfire/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/m68k/coldfire/entry.S
+++ linux-5.4.5-rt3/arch/m68k/coldfire/entry.S
@@ -108,7 +108,7 @@ ret_from_exception:
 	btst	#5,%sp@(PT_OFF_SR)	/* check if returning to kernel */
 	jeq	Luser_return		/* if so, skip resched, signals */
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	movel	%sp,%d1			/* get thread_info pointer */
 	andl	#-THREAD_SIZE,%d1	/* at base of kernel stack */
 	movel	%d1,%a0
Index: linux-5.4.5-rt3/arch/microblaze/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/microblaze/kernel/entry.S
+++ linux-5.4.5-rt3/arch/microblaze/kernel/entry.S
@@ -728,7 +728,7 @@ no_intr_resched:
 	bri	6f;
 /* MS: Return to kernel state. */
 2:
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	lwi	r11, CURRENT_TASK, TS_THREAD_INFO;
 	/* MS: get preempt_count from thread info */
 	lwi	r5, r11, TI_PREEMPT_COUNT;
Index: linux-5.4.5-rt3/arch/mips/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/mips/Kconfig
+++ linux-5.4.5-rt3/arch/mips/Kconfig
@@ -2586,7 +2586,7 @@ config MIPS_CRC_SUPPORT
 #
 config HIGHMEM
 	bool "High Memory Support"
-	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA
+	depends on 32BIT && CPU_SUPPORTS_HIGHMEM && SYS_SUPPORTS_HIGHMEM && !CPU_MIPS32_3_5_EVA && !PREEMPT_RT
 
 config CPU_SUPPORTS_HIGHMEM
 	bool
Index: linux-5.4.5-rt3/arch/mips/include/asm/asmmacro.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/mips/include/asm/asmmacro.h
+++ linux-5.4.5-rt3/arch/mips/include/asm/asmmacro.h
@@ -63,7 +63,7 @@
 	.endm
 
 	.macro	local_irq_disable reg=t0
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	lw      \reg, TI_PRE_COUNT($28)
 	addi    \reg, \reg, 1
 	sw      \reg, TI_PRE_COUNT($28)
@@ -73,7 +73,7 @@
 	xori	\reg, \reg, 1
 	mtc0	\reg, CP0_STATUS
 	irq_disable_hazard
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	lw      \reg, TI_PRE_COUNT($28)
 	addi    \reg, \reg, -1
 	sw      \reg, TI_PRE_COUNT($28)
Index: linux-5.4.5-rt3/arch/mips/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/mips/kernel/entry.S
+++ linux-5.4.5-rt3/arch/mips/kernel/entry.S
@@ -19,7 +19,7 @@
 #include <asm/thread_info.h>
 #include <asm/war.h>
 
-#ifndef CONFIG_PREEMPT
+#ifndef CONFIG_PREEMPTION
 #define resume_kernel	restore_all
 #else
 #define __ret_from_irq	ret_from_exception
@@ -27,7 +27,7 @@
 
 	.text
 	.align	5
-#ifndef CONFIG_PREEMPT
+#ifndef CONFIG_PREEMPTION
 FEXPORT(ret_from_exception)
 	local_irq_disable			# preempt stop
 	b	__ret_from_irq
@@ -53,7 +53,7 @@ resume_userspace:
 	bnez	t0, work_pending
 	j	restore_all
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 resume_kernel:
 	local_irq_disable
 	lw	t0, TI_PRE_COUNT($28)
Index: linux-5.4.5-rt3/arch/nds32/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/nds32/Kconfig
+++ linux-5.4.5-rt3/arch/nds32/Kconfig
@@ -61,7 +61,7 @@ config GENERIC_HWEIGHT
 
 config GENERIC_LOCKBREAK
 	def_bool y
-	depends on PREEMPT
+	depends on PREEMPTION
 
 config TRACE_IRQFLAGS_SUPPORT
 	def_bool y
Index: linux-5.4.5-rt3/arch/nds32/kernel/ex-exit.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/nds32/kernel/ex-exit.S
+++ linux-5.4.5-rt3/arch/nds32/kernel/ex-exit.S
@@ -72,7 +72,7 @@
 	restore_user_regs_last
 	.endm
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	.macro	preempt_stop
 	.endm
 #else
@@ -158,7 +158,7 @@ no_work_pending:
 /*
  * preemptive kernel
  */
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 resume_kernel:
 	gie_disable
 	lwi	$t0, [tsk+#TSK_TI_PREEMPT]
Index: linux-5.4.5-rt3/arch/nios2/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/nios2/kernel/entry.S
+++ linux-5.4.5-rt3/arch/nios2/kernel/entry.S
@@ -365,7 +365,7 @@ ENTRY(ret_from_interrupt)
 	ldw	r1, PT_ESTATUS(sp)	/* check if returning to kernel */
 	TSTBNZ	r1, r1, ESTATUS_EU, Luser_return
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	GET_THREAD_INFO	r1
 	ldw	r4, TI_PREEMPT_COUNT(r1)
 	bne	r4, r0, restore_all
Index: linux-5.4.5-rt3/arch/parisc/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/parisc/Kconfig
+++ linux-5.4.5-rt3/arch/parisc/Kconfig
@@ -82,7 +82,7 @@ config STACK_GROWSUP
 config GENERIC_LOCKBREAK
 	bool
 	default y
-	depends on SMP && PREEMPT
+	depends on SMP && PREEMPTION
 
 config ARCH_HAS_ILOG2_U32
 	bool
Index: linux-5.4.5-rt3/arch/parisc/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/parisc/kernel/entry.S
+++ linux-5.4.5-rt3/arch/parisc/kernel/entry.S
@@ -940,14 +940,14 @@ intr_restore:
 	rfi
 	nop
 
-#ifndef CONFIG_PREEMPT
+#ifndef CONFIG_PREEMPTION
 # define intr_do_preempt	intr_restore
-#endif /* !CONFIG_PREEMPT */
+#endif /* !CONFIG_PREEMPTION */
 
 	.import schedule,code
 intr_do_resched:
 	/* Only call schedule on return to userspace. If we're returning
-	 * to kernel space, we may schedule if CONFIG_PREEMPT, otherwise
+	 * to kernel space, we may schedule if CONFIG_PREEMPTION, otherwise
 	 * we jump back to intr_restore.
 	 */
 	LDREG	PT_IASQ0(%r16), %r20
@@ -979,7 +979,7 @@ intr_do_resched:
 	 * and preempt_count is 0. otherwise, we continue on
 	 * our merry way back to the current running task.
 	 */
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	.import preempt_schedule_irq,code
 intr_do_preempt:
 	rsm	PSW_SM_I, %r0		/* disable interrupts */
@@ -999,7 +999,7 @@ intr_do_preempt:
 	nop
 
 	b,n	intr_restore		/* ssm PSW_SM_I done by intr_restore */
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 	/*
 	 * External interrupts.
Index: linux-5.4.5-rt3/arch/powerpc/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/Kconfig
+++ linux-5.4.5-rt3/arch/powerpc/Kconfig
@@ -106,7 +106,7 @@ config LOCKDEP_SUPPORT
 config GENERIC_LOCKBREAK
 	bool
 	default y
-	depends on SMP && PREEMPT
+	depends on SMP && PREEMPTION
 
 config GENERIC_HWEIGHT
 	bool
@@ -144,6 +144,7 @@ config PPC
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select ARCH_OPTIONAL_KERNEL_RWX		if ARCH_HAS_STRICT_KERNEL_RWX
 	select ARCH_SUPPORTS_ATOMIC_RMW
+	select ARCH_SUPPORTS_RT
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_CMPXCHG_LOCKREF		if PPC64
 	select ARCH_WANT_IPC_PARSE_VERSION
@@ -221,6 +222,7 @@ config PPC
 	select HAVE_HARDLOCKUP_DETECTOR_PERF	if PERF_EVENTS && HAVE_PERF_EVENTS_NMI && !HAVE_HARDLOCKUP_DETECTOR_ARCH
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select HAVE_RCU_TABLE_FREE		if SMP
 	select HAVE_RCU_TABLE_NO_INVALIDATE	if HAVE_RCU_TABLE_FREE
 	select HAVE_MMU_GATHER_PAGE_SIZE
@@ -398,7 +400,7 @@ menu "Kernel options"
 
 config HIGHMEM
 	bool "High memory support"
-	depends on PPC32
+	depends on PPC32 && !PREEMPT_RT
 
 source "kernel/Kconfig.hz"
 
Index: linux-5.4.5-rt3/arch/powerpc/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/powerpc/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef _ASM_POWERPC_SPINLOCK_TYPES_H
 #define _ASM_POWERPC_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int slock;
 } arch_spinlock_t;
Index: linux-5.4.5-rt3/arch/powerpc/include/asm/stackprotector.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/include/asm/stackprotector.h
+++ linux-5.4.5-rt3/arch/powerpc/include/asm/stackprotector.h
@@ -24,7 +24,11 @@ static __always_inline void boot_init_st
 	unsigned long canary;
 
 	/* Try to get a semi random initial value. */
+#ifdef CONFIG_PREEMPT_RT
+	canary = (unsigned long)&canary;
+#else
 	canary = get_random_canary();
+#endif
 	canary ^= mftb();
 	canary ^= LINUX_VERSION_CODE;
 	canary &= CANARY_MASK;
Index: linux-5.4.5-rt3/arch/powerpc/include/asm/thread_info.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/include/asm/thread_info.h
+++ linux-5.4.5-rt3/arch/powerpc/include/asm/thread_info.h
@@ -30,6 +30,8 @@
 struct thread_info {
 	int		preempt_count;		/* 0 => preemptable,
 						   <0 => BUG */
+	int             preempt_lazy_count;	/* 0 => preemptable,
+						   <0 => BUG */
 	unsigned long	local_flags;		/* private flags for thread */
 #ifdef CONFIG_LIVEPATCH
 	unsigned long *livepatch_sp;
@@ -80,11 +82,12 @@ void arch_setup_new_exec(void);
 #define TIF_SINGLESTEP		8	/* singlestepping active */
 #define TIF_NOHZ		9	/* in adaptive nohz mode */
 #define TIF_SECCOMP		10	/* secure computing */
-#define TIF_RESTOREALL		11	/* Restore all regs (implies NOERROR) */
-#define TIF_NOERROR		12	/* Force successful syscall return */
+
+#define TIF_NEED_RESCHED_LAZY	11	/* lazy rescheduling necessary */
+#define TIF_SYSCALL_TRACEPOINT	12	/* syscall tracepoint instrumentation */
+
 #define TIF_NOTIFY_RESUME	13	/* callback before returning to user */
 #define TIF_UPROBE		14	/* breakpointed or single-stepping */
-#define TIF_SYSCALL_TRACEPOINT	15	/* syscall tracepoint instrumentation */
 #define TIF_EMULATE_STACK_STORE	16	/* Is an instruction emulation
 						for stack store? */
 #define TIF_MEMDIE		17	/* is terminating due to OOM killer */
@@ -93,6 +96,9 @@ void arch_setup_new_exec(void);
 #endif
 #define TIF_POLLING_NRFLAG	19	/* true if poll_idle() is polling TIF_NEED_RESCHED */
 #define TIF_32BIT		20	/* 32 bit binary */
+#define TIF_RESTOREALL		21	/* Restore all regs (implies NOERROR) */
+#define TIF_NOERROR		22	/* Force successful syscall return */
+
 
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE	(1<<TIF_SYSCALL_TRACE)
@@ -112,6 +118,7 @@ void arch_setup_new_exec(void);
 #define _TIF_SYSCALL_TRACEPOINT	(1<<TIF_SYSCALL_TRACEPOINT)
 #define _TIF_EMULATE_STACK_STORE	(1<<TIF_EMULATE_STACK_STORE)
 #define _TIF_NOHZ		(1<<TIF_NOHZ)
+#define _TIF_NEED_RESCHED_LAZY	(1<<TIF_NEED_RESCHED_LAZY)
 #define _TIF_FSCHECK		(1<<TIF_FSCHECK)
 #define _TIF_SYSCALL_EMU	(1<<TIF_SYSCALL_EMU)
 #define _TIF_SYSCALL_DOTRACE	(_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
@@ -121,8 +128,9 @@ void arch_setup_new_exec(void);
 #define _TIF_USER_WORK_MASK	(_TIF_SIGPENDING | _TIF_NEED_RESCHED | \
 				 _TIF_NOTIFY_RESUME | _TIF_UPROBE | \
 				 _TIF_RESTORE_TM | _TIF_PATCH_PENDING | \
-				 _TIF_FSCHECK)
+				 _TIF_FSCHECK | _TIF_NEED_RESCHED_LAZY)
 #define _TIF_PERSYSCALL_MASK	(_TIF_RESTOREALL|_TIF_NOERROR)
+#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
 
 /* Bits in local_flags */
 /* Don't move TLF_NAPPING without adjusting the code in entry_32.S */
Index: linux-5.4.5-rt3/arch/powerpc/kernel/asm-offsets.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/asm-offsets.c
+++ linux-5.4.5-rt3/arch/powerpc/kernel/asm-offsets.c
@@ -167,6 +167,7 @@ int main(void)
 	OFFSET(TI_FLAGS, thread_info, flags);
 	OFFSET(TI_LOCAL_FLAGS, thread_info, local_flags);
 	OFFSET(TI_PREEMPT, thread_info, preempt_count);
+	OFFSET(TI_PREEMPT_LAZY, thread_info, preempt_lazy_count);
 
 #ifdef CONFIG_PPC64
 	OFFSET(DCACHEL1BLOCKSIZE, ppc64_caches, l1d.block_size);
Index: linux-5.4.5-rt3/arch/powerpc/kernel/entry_32.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/entry_32.S
+++ linux-5.4.5-rt3/arch/powerpc/kernel/entry_32.S
@@ -400,7 +400,9 @@ ret_from_syscall:
 	MTMSRD(r10)
 	lwz	r9,TI_FLAGS(r2)
 	li	r8,-MAX_ERRNO
-	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
+	lis	r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@h
+	ori	r0,r0, (_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@l
+	and.	r0,r9,r0
 	bne-	syscall_exit_work
 	cmplw	0,r3,r8
 	blt+	syscall_exit_cont
@@ -515,13 +517,13 @@ syscall_dotrace:
 	b	syscall_dotrace_cont
 
 syscall_exit_work:
-	andi.	r0,r9,_TIF_RESTOREALL
+	andis.	r0,r9,_TIF_RESTOREALL@h
 	beq+	0f
 	REST_NVGPRS(r1)
 	b	2f
 0:	cmplw	0,r3,r8
 	blt+	1f
-	andi.	r0,r9,_TIF_NOERROR
+	andis.	r0,r9,_TIF_NOERROR@h
 	bne-	1f
 	lwz	r11,_CCR(r1)			/* Load CR */
 	neg	r3,r3
@@ -530,12 +532,12 @@ syscall_exit_work:
 
 1:	stw	r6,RESULT(r1)	/* Save result */
 	stw	r3,GPR3(r1)	/* Update return value */
-2:	andi.	r0,r9,(_TIF_PERSYSCALL_MASK)
+2:	andi.	r0,r9,(_TIF_PERSYSCALL_MASK)@h
 	beq	4f
 
 	/* Clear per-syscall TIF flags if any are set.  */
 
-	li	r11,_TIF_PERSYSCALL_MASK
+	li	r11,_TIF_PERSYSCALL_MASK@h
 	addi	r12,r2,TI_FLAGS
 3:	lwarx	r8,0,r12
 	andc	r8,r8,r11
@@ -897,13 +899,20 @@ resume_kernel:
 	bne-	0b
 1:
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	/* check current_thread_info->preempt_count */
 	lwz	r0,TI_PREEMPT(r2)
 	cmpwi	0,r0,0		/* if non-zero, just restore regs and return */
 	bne	restore_kuap
 	andi.	r8,r8,_TIF_NEED_RESCHED
+	bne+	1f
+	lwz	r0,TI_PREEMPT_LAZY(r2)
+	cmpwi	0,r0,0          /* if non-zero, just restore regs and return */
+	bne	restore_kuap
+	lwz	r0,TI_FLAGS(r2)
+	andi.	r0,r0,_TIF_NEED_RESCHED_LAZY
 	beq+	restore_kuap
+1:
 	lwz	r3,_MSR(r1)
 	andi.	r0,r3,MSR_EE	/* interrupts off? */
 	beq	restore_kuap	/* don't schedule if so */
@@ -921,7 +930,7 @@ resume_kernel:
 	 */
 	bl	trace_hardirqs_on
 #endif
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 restore_kuap:
 	kuap_restore r1, r2, r9, r10, r0
 
@@ -1224,7 +1233,7 @@ global_dbcr0:
 #endif /* !(CONFIG_4xx || CONFIG_BOOKE) */
 
 do_work:			/* r10 contains MSR_KERNEL here */
-	andi.	r0,r9,_TIF_NEED_RESCHED
+	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
 	beq	do_user_signal
 
 do_resched:			/* r10 contains MSR_KERNEL here */
@@ -1245,7 +1254,7 @@ recheck:
 	SYNC
 	MTMSRD(r10)		/* disable interrupts */
 	lwz	r9,TI_FLAGS(r2)
-	andi.	r0,r9,_TIF_NEED_RESCHED
+	andi.	r0,r9,_TIF_NEED_RESCHED_MASK
 	bne-	do_resched
 	andi.	r0,r9,_TIF_USER_WORK_MASK
 	beq	restore_user
Index: linux-5.4.5-rt3/arch/powerpc/kernel/entry_64.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/entry_64.S
+++ linux-5.4.5-rt3/arch/powerpc/kernel/entry_64.S
@@ -240,7 +240,9 @@ system_call_exit:
 
 	ld	r9,TI_FLAGS(r12)
 	li	r11,-MAX_ERRNO
-	andi.	r0,r9,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)
+	lis	r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@h
+	ori	r0,r0,(_TIF_SYSCALL_DOTRACE|_TIF_SINGLESTEP|_TIF_USER_WORK_MASK|_TIF_PERSYSCALL_MASK)@l
+	and.	r0,r9,r0
 	bne-	.Lsyscall_exit_work
 
 	andi.	r0,r8,MSR_FP
@@ -363,25 +365,25 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	/* If TIF_RESTOREALL is set, don't scribble on either r3 or ccr.
 	 If TIF_NOERROR is set, just save r3 as it is. */
 
-	andi.	r0,r9,_TIF_RESTOREALL
+	andis.	r0,r9,_TIF_RESTOREALL@h
 	beq+	0f
 	REST_NVGPRS(r1)
 	b	2f
 0:	cmpld	r3,r11		/* r11 is -MAX_ERRNO */
 	blt+	1f
-	andi.	r0,r9,_TIF_NOERROR
+	andis.	r0,r9,_TIF_NOERROR@h
 	bne-	1f
 	ld	r5,_CCR(r1)
 	neg	r3,r3
 	oris	r5,r5,0x1000	/* Set SO bit in CR */
 	std	r5,_CCR(r1)
 1:	std	r3,GPR3(r1)
-2:	andi.	r0,r9,(_TIF_PERSYSCALL_MASK)
+2:	andis.	r0,r9,(_TIF_PERSYSCALL_MASK)@h
 	beq	4f
 
 	/* Clear per-syscall TIF flags if any are set.  */
 
-	li	r11,_TIF_PERSYSCALL_MASK
+	lis	r11,(_TIF_PERSYSCALL_MASK)@h
 	addi	r12,r12,TI_FLAGS
 3:	ldarx	r10,0,r12
 	andc	r10,r10,r11
@@ -786,7 +788,7 @@ _GLOBAL(ret_from_except_lite)
 	bl	restore_math
 	b	restore
 #endif
-1:	andi.	r0,r4,_TIF_NEED_RESCHED
+1:	andi.	r0,r4,_TIF_NEED_RESCHED_MASK
 	beq	2f
 	bl	restore_interrupts
 	SCHEDULE_USER
@@ -846,12 +848,20 @@ resume_kernel:
 	bne-	0b
 1:
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	/* Check if we need to preempt */
+	lwz	r8,TI_PREEMPT(r9)
+	cmpwi	0,r8,0		/* if non-zero, just restore regs and return */
+	bne	restore
 	andi.	r0,r4,_TIF_NEED_RESCHED
+	bne+	check_count
+
+	andi.	r0,r4,_TIF_NEED_RESCHED_LAZY
 	beq+	restore
+	lwz	r8,TI_PREEMPT_LAZY(r9)
+
 	/* Check that preempt_count() == 0 and interrupts are enabled */
-	lwz	r8,TI_PREEMPT(r9)
+check_count:
 	cmpwi	cr0,r8,0
 	bne	restore
 	ld	r0,SOFTE(r1)
@@ -877,7 +887,7 @@ resume_kernel:
 	li	r10,MSR_RI
 	mtmsrd	r10,1		  /* Update machine state */
 #endif /* CONFIG_PPC_BOOK3E */
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 	.globl	fast_exc_return_irq
 fast_exc_return_irq:
Index: linux-5.4.5-rt3/arch/powerpc/kernel/irq.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/irq.c
+++ linux-5.4.5-rt3/arch/powerpc/kernel/irq.c
@@ -679,10 +679,12 @@ void *mcheckirq_ctx[NR_CPUS] __read_most
 void *softirq_ctx[NR_CPUS] __read_mostly;
 void *hardirq_ctx[NR_CPUS] __read_mostly;
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	call_do_softirq(softirq_ctx[smp_processor_id()]);
 }
+#endif
 
 irq_hw_number_t virq_to_hw(unsigned int virq)
 {
Index: linux-5.4.5-rt3/arch/powerpc/kernel/misc_32.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/misc_32.S
+++ linux-5.4.5-rt3/arch/powerpc/kernel/misc_32.S
@@ -37,6 +37,7 @@
  * We store the saved ksp_limit in the unused part
  * of the STACK_FRAME_OVERHEAD
  */
+#ifndef CONFIG_PREEMPT_RT
 _GLOBAL(call_do_softirq)
 	mflr	r0
 	stw	r0,4(r1)
@@ -52,6 +53,7 @@ _GLOBAL(call_do_softirq)
 	stw	r10,THREAD+KSP_LIMIT(r2)
 	mtlr	r0
 	blr
+#endif
 
 /*
  * void call_do_irq(struct pt_regs *regs, void *sp);
Index: linux-5.4.5-rt3/arch/powerpc/kernel/misc_64.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/misc_64.S
+++ linux-5.4.5-rt3/arch/powerpc/kernel/misc_64.S
@@ -27,6 +27,7 @@
 
 	.text
 
+#ifndef CONFIG_PREEMPT_RT
 _GLOBAL(call_do_softirq)
 	mflr	r0
 	std	r0,16(r1)
@@ -37,6 +38,7 @@ _GLOBAL(call_do_softirq)
 	ld	r0,16(r1)
 	mtlr	r0
 	blr
+#endif
 
 _GLOBAL(call_do_irq)
 	mflr	r0
Index: linux-5.4.5-rt3/arch/powerpc/kernel/traps.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/traps.c
+++ linux-5.4.5-rt3/arch/powerpc/kernel/traps.c
@@ -171,7 +171,6 @@ extern void panic_flush_kmsg_start(void)
 
 extern void panic_flush_kmsg_end(void)
 {
-	printk_safe_flush_on_panic();
 	kmsg_dump(KMSG_DUMP_PANIC);
 	bust_spinlocks(0);
 	debug_locks_off();
@@ -261,12 +260,17 @@ static char *get_mmu_str(void)
 
 static int __die(const char *str, struct pt_regs *regs, long err)
 {
+	const char *pr = "";
+
 	printk("Oops: %s, sig: %ld [#%d]\n", str, err, ++die_counter);
 
+	if (IS_ENABLED(CONFIG_PREEMPTION))
+		pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
+
 	printk("%s PAGE_SIZE=%luK%s%s%s%s%s%s %s\n",
 	       IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) ? "LE" : "BE",
 	       PAGE_SIZE / 1024, get_mmu_str(),
-	       IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "",
+	       pr,
 	       IS_ENABLED(CONFIG_SMP) ? " SMP" : "",
 	       IS_ENABLED(CONFIG_SMP) ? (" NR_CPUS=" __stringify(NR_CPUS)) : "",
 	       debug_pagealloc_enabled() ? " DEBUG_PAGEALLOC" : "",
Index: linux-5.4.5-rt3/arch/powerpc/kernel/watchdog.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kernel/watchdog.c
+++ linux-5.4.5-rt3/arch/powerpc/kernel/watchdog.c
@@ -181,11 +181,6 @@ static void watchdog_smp_panic(int cpu,
 
 	wd_smp_unlock(&flags);
 
-	printk_safe_flush();
-	/*
-	 * printk_safe_flush() seems to require another print
-	 * before anything actually goes out to console.
-	 */
 	if (sysctl_hardlockup_all_cpu_backtrace)
 		trigger_allbutself_cpu_backtrace();
 
Index: linux-5.4.5-rt3/arch/powerpc/kvm/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/kvm/Kconfig
+++ linux-5.4.5-rt3/arch/powerpc/kvm/Kconfig
@@ -178,6 +178,7 @@ config KVM_E500MC
 config KVM_MPIC
 	bool "KVM in-kernel MPIC emulation"
 	depends on KVM && E500
+	depends on !PREEMPT_RT
 	select HAVE_KVM_IRQCHIP
 	select HAVE_KVM_IRQFD
 	select HAVE_KVM_IRQ_ROUTING
Index: linux-5.4.5-rt3/arch/powerpc/platforms/ps3/device-init.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/platforms/ps3/device-init.c
+++ linux-5.4.5-rt3/arch/powerpc/platforms/ps3/device-init.c
@@ -738,8 +738,8 @@ static int ps3_notification_read_write(s
 	}
 	pr_debug("%s:%u: notification %s issued\n", __func__, __LINE__, op);
 
-	res = wait_event_interruptible(dev->done.wait,
-				       dev->done.done || kthread_should_stop());
+	res = swait_event_interruptible_exclusive(dev->done.wait,
+						  dev->done.done || kthread_should_stop());
 	if (kthread_should_stop())
 		res = -EINTR;
 	if (res) {
Index: linux-5.4.5-rt3/arch/powerpc/platforms/pseries/iommu.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/powerpc/platforms/pseries/iommu.c
+++ linux-5.4.5-rt3/arch/powerpc/platforms/pseries/iommu.c
@@ -24,6 +24,7 @@
 #include <linux/of.h>
 #include <linux/iommu.h>
 #include <linux/rculist.h>
+#include <linux/locallock.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -178,6 +179,7 @@ static int tce_build_pSeriesLP(struct io
 }
 
 static DEFINE_PER_CPU(__be64 *, tce_page);
+static DEFINE_LOCAL_IRQ_LOCK(tcp_page_lock);
 
 static int tce_buildmulti_pSeriesLP(struct iommu_table *tbl, long tcenum,
 				     long npages, unsigned long uaddr,
@@ -198,7 +200,8 @@ static int tce_buildmulti_pSeriesLP(stru
 		                           direction, attrs);
 	}
 
-	local_irq_save(flags);	/* to protect tcep and the page behind it */
+	/* to protect tcep and the page behind it */
+	local_lock_irqsave(tcp_page_lock, flags);
 
 	tcep = __this_cpu_read(tce_page);
 
@@ -209,7 +212,7 @@ static int tce_buildmulti_pSeriesLP(stru
 		tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
 		/* If allocation fails, fall back to the loop implementation */
 		if (!tcep) {
-			local_irq_restore(flags);
+			local_unlock_irqrestore(tcp_page_lock, flags);
 			return tce_build_pSeriesLP(tbl, tcenum, npages, uaddr,
 					    direction, attrs);
 		}
@@ -243,7 +246,7 @@ static int tce_buildmulti_pSeriesLP(stru
 		tcenum += limit;
 	} while (npages > 0 && !rc);
 
-	local_irq_restore(flags);
+	local_unlock_irqrestore(tcp_page_lock, flags);
 
 	if (unlikely(rc == H_NOT_ENOUGH_RESOURCES)) {
 		ret = (int)rc;
@@ -401,13 +404,14 @@ static int tce_setrange_multi_pSeriesLP(
 	u64 rc = 0;
 	long l, limit;
 
-	local_irq_disable();	/* to protect tcep and the page behind it */
+	/* to protect tcep and the page behind it */
+	local_lock_irq(tcp_page_lock);
 	tcep = __this_cpu_read(tce_page);
 
 	if (!tcep) {
 		tcep = (__be64 *)__get_free_page(GFP_ATOMIC);
 		if (!tcep) {
-			local_irq_enable();
+			local_unlock_irq(tcp_page_lock);
 			return -ENOMEM;
 		}
 		__this_cpu_write(tce_page, tcep);
@@ -453,7 +457,7 @@ static int tce_setrange_multi_pSeriesLP(
 
 	/* error cleanup: caller will clear whole range */
 
-	local_irq_enable();
+	local_unlock_irq(tcp_page_lock);
 	return rc;
 }
 
Index: linux-5.4.5-rt3/arch/riscv/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/riscv/kernel/entry.S
+++ linux-5.4.5-rt3/arch/riscv/kernel/entry.S
@@ -155,7 +155,7 @@ _save_context:
 	REG_L x2,  PT_SP(sp)
 	.endm
 
-#if !IS_ENABLED(CONFIG_PREEMPT)
+#if !IS_ENABLED(CONFIG_PREEMPTION)
 .set resume_kernel, restore_all
 #endif
 
@@ -269,7 +269,7 @@ restore_all:
 	RESTORE_ALL
 	sret
 
-#if IS_ENABLED(CONFIG_PREEMPT)
+#if IS_ENABLED(CONFIG_PREEMPTION)
 resume_kernel:
 	REG_L s0, TASK_TI_PREEMPT_COUNT(tp)
 	bnez s0, restore_all
Index: linux-5.4.5-rt3/arch/s390/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/s390/Kconfig
+++ linux-5.4.5-rt3/arch/s390/Kconfig
@@ -30,7 +30,7 @@ config GENERIC_BUG_RELATIVE_POINTERS
 	def_bool y
 
 config GENERIC_LOCKBREAK
-	def_bool y if PREEMPT
+	def_bool y if PREEMPTTION
 
 config PGSTE
 	def_bool y if KVM
Index: linux-5.4.5-rt3/arch/s390/include/asm/preempt.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/s390/include/asm/preempt.h
+++ linux-5.4.5-rt3/arch/s390/include/asm/preempt.h
@@ -130,11 +130,11 @@ static inline bool should_resched(int pr
 
 #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 extern asmlinkage void preempt_schedule(void);
 #define __preempt_schedule() preempt_schedule()
 extern asmlinkage void preempt_schedule_notrace(void);
 #define __preempt_schedule_notrace() preempt_schedule_notrace()
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 #endif /* __ASM_PREEMPT_H */
Index: linux-5.4.5-rt3/arch/s390/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/s390/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/s390/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	int lock;
 } __attribute__ ((aligned (4))) arch_spinlock_t;
Index: linux-5.4.5-rt3/arch/s390/kernel/dumpstack.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/s390/kernel/dumpstack.c
+++ linux-5.4.5-rt3/arch/s390/kernel/dumpstack.c
@@ -194,6 +194,8 @@ void die(struct pt_regs *regs, const cha
 	       regs->int_code >> 17, ++die_counter);
 #ifdef CONFIG_PREEMPT
 	pr_cont("PREEMPT ");
+#elif defined(CONFIG_PREEMPT_RT)
+	pr_cont("PREEMPT_RT ");
 #endif
 	pr_cont("SMP ");
 	if (debug_pagealloc_enabled())
Index: linux-5.4.5-rt3/arch/s390/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/s390/kernel/entry.S
+++ linux-5.4.5-rt3/arch/s390/kernel/entry.S
@@ -790,7 +790,7 @@ ENTRY(io_int_handler)
 .Lio_work:
 	tm	__PT_PSW+1(%r11),0x01	# returning to user ?
 	jo	.Lio_work_user		# yes -> do resched & signal
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	# check for preemptive scheduling
 	icm	%r0,15,__LC_PREEMPT_COUNT
 	jnz	.Lio_restore		# preemption is disabled
Index: linux-5.4.5-rt3/arch/sh/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/sh/Kconfig
+++ linux-5.4.5-rt3/arch/sh/Kconfig
@@ -108,7 +108,7 @@ config GENERIC_CALIBRATE_DELAY
 
 config GENERIC_LOCKBREAK
 	def_bool y
-	depends on SMP && PREEMPT
+	depends on SMP && PREEMPTION
 
 config ARCH_SUSPEND_POSSIBLE
 	def_bool n
Index: linux-5.4.5-rt3/arch/sh/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/sh/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/sh/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SH_SPINLOCK_TYPES_H
 #define __ASM_SH_SPINLOCK_TYPES_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 typedef struct {
 	volatile unsigned int lock;
 } arch_spinlock_t;
Index: linux-5.4.5-rt3/arch/sh/kernel/cpu/sh5/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/sh/kernel/cpu/sh5/entry.S
+++ linux-5.4.5-rt3/arch/sh/kernel/cpu/sh5/entry.S
@@ -86,7 +86,7 @@
 	andi	r6, ~0xf0, r6;		\
 	putcon	r6, SR;
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 #  define preempt_stop()	CLI()
 #else
 #  define preempt_stop()
@@ -884,7 +884,7 @@ ret_from_exception:
 
 	/* Check softirqs */
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	pta   ret_from_syscall, tr0
 	blink   tr0, ZERO
 
Index: linux-5.4.5-rt3/arch/sh/kernel/entry-common.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/sh/kernel/entry-common.S
+++ linux-5.4.5-rt3/arch/sh/kernel/entry-common.S
@@ -41,7 +41,7 @@
  */
 #include <asm/dwarf.h>
 
-#if defined(CONFIG_PREEMPT)
+#if defined(CONFIG_PREEMPTION)
 #  define preempt_stop()	cli ; TRACE_IRQS_OFF
 #else
 #  define preempt_stop()
@@ -84,7 +84,7 @@ ENTRY(ret_from_irq)
 	get_current_thread_info r8, r0
 	bt	resume_kernel	! Yes, it's from kernel, go back soon
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 	bra	resume_userspace
 	 nop
 ENTRY(resume_kernel)
Index: linux-5.4.5-rt3/arch/sh/kernel/irq.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/sh/kernel/irq.c
+++ linux-5.4.5-rt3/arch/sh/kernel/irq.c
@@ -148,6 +148,7 @@ void irq_ctx_exit(int cpu)
 	hardirq_ctx[cpu] = NULL;
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	struct thread_info *curctx;
@@ -175,6 +176,7 @@ void do_softirq_own_stack(void)
 		  "r5", "r6", "r7", "r8", "r9", "r15", "t", "pr"
 	);
 }
+#endif
 #else
 static inline void handle_one_irq(unsigned int irq)
 {
Index: linux-5.4.5-rt3/arch/sparc/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/sparc/Kconfig
+++ linux-5.4.5-rt3/arch/sparc/Kconfig
@@ -277,7 +277,7 @@ config US3_MC
 config GENERIC_LOCKBREAK
 	bool
 	default y
-	depends on SPARC64 && SMP && PREEMPT
+	depends on SPARC64 && SMP && PREEMPTION
 
 config NUMA
 	bool "NUMA support"
Index: linux-5.4.5-rt3/arch/sparc/kernel/irq_64.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/sparc/kernel/irq_64.c
+++ linux-5.4.5-rt3/arch/sparc/kernel/irq_64.c
@@ -854,6 +854,7 @@ void __irq_entry handler_irq(int pil, st
 	set_irq_regs(old_regs);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	void *orig_sp, *sp = softirq_stack[smp_processor_id()];
@@ -868,6 +869,7 @@ void do_softirq_own_stack(void)
 	__asm__ __volatile__("mov %0, %%sp"
 			     : : "r" (orig_sp));
 }
+#endif
 
 #ifdef CONFIG_HOTPLUG_CPU
 void fixup_irqs(void)
Index: linux-5.4.5-rt3/arch/sparc/kernel/rtrap_64.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/sparc/kernel/rtrap_64.S
+++ linux-5.4.5-rt3/arch/sparc/kernel/rtrap_64.S
@@ -310,7 +310,7 @@ kern_rtt_restore:
 		retry
 
 to_kernel:
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 		ldsw			[%g6 + TI_PRE_COUNT], %l5
 		brnz			%l5, kern_fpucheck
 		 ldx			[%g6 + TI_FLAGS], %l5
Index: linux-5.4.5-rt3/arch/x86/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/Kconfig
+++ linux-5.4.5-rt3/arch/x86/Kconfig
@@ -90,6 +90,7 @@ config X86
 	select ARCH_SUPPORTS_ACPI
 	select ARCH_SUPPORTS_ATOMIC_RMW
 	select ARCH_SUPPORTS_NUMA_BALANCING	if X86_64
+	select ARCH_SUPPORTS_RT
 	select ARCH_USE_BUILTIN_BSWAP
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
@@ -132,8 +133,8 @@ config X86
 	select HAVE_ALIGNED_STRUCT_PAGE		if SLUB
 	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_ARCH_HUGE_VMAP		if X86_64 || X86_PAE
-	select HAVE_ARCH_JUMP_LABEL
-	select HAVE_ARCH_JUMP_LABEL_RELATIVE
+	select HAVE_ARCH_JUMP_LABEL		if !PREEMPT_RT
+	select HAVE_ARCH_JUMP_LABEL_RELATIVE	if !PREEMPT_RT
 	select HAVE_ARCH_KASAN			if X86_64
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_MMAP_RND_BITS		if MMU
@@ -199,6 +200,7 @@ config X86
 	select HAVE_PCI
 	select HAVE_PERF_REGS
 	select HAVE_PERF_USER_STACK_DUMP
+	select HAVE_PREEMPT_LAZY
 	select HAVE_RCU_TABLE_FREE		if PARAVIRT
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE		if X86_64 && (UNWINDER_FRAME_POINTER || UNWINDER_ORC) && STACK_VALIDATION
Index: linux-5.4.5-rt3/arch/x86/crypto/aesni-intel_glue.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/crypto/aesni-intel_glue.c
+++ linux-5.4.5-rt3/arch/x86/crypto/aesni-intel_glue.c
@@ -387,14 +387,14 @@ static int ecb_encrypt(struct skcipher_r
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_ecb_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -409,14 +409,14 @@ static int ecb_decrypt(struct skcipher_r
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_ecb_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -431,14 +431,14 @@ static int cbc_encrypt(struct skcipher_r
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_cbc_enc(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -453,14 +453,14 @@ static int cbc_decrypt(struct skcipher_r
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes)) {
+		kernel_fpu_begin();
 		aesni_cbc_dec(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			      nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
@@ -510,18 +510,20 @@ static int ctr_crypt(struct skcipher_req
 
 	err = skcipher_walk_virt(&walk, req, true);
 
-	kernel_fpu_begin();
 	while ((nbytes = walk.nbytes) >= AES_BLOCK_SIZE) {
+		kernel_fpu_begin();
 		aesni_ctr_enc_tfm(ctx, walk.dst.virt.addr, walk.src.virt.addr,
 			              nbytes & AES_BLOCK_MASK, walk.iv);
+		kernel_fpu_end();
 		nbytes &= AES_BLOCK_SIZE - 1;
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 	if (walk.nbytes) {
+		kernel_fpu_begin();
 		ctr_crypt_final(ctx, &walk);
+		kernel_fpu_end();
 		err = skcipher_walk_done(&walk, 0);
 	}
-	kernel_fpu_end();
 
 	return err;
 }
Index: linux-5.4.5-rt3/arch/x86/crypto/cast5_avx_glue.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/crypto/cast5_avx_glue.c
+++ linux-5.4.5-rt3/arch/x86/crypto/cast5_avx_glue.c
@@ -46,7 +46,7 @@ static inline void cast5_fpu_end(bool fp
 
 static int ecb_crypt(struct skcipher_request *req, bool enc)
 {
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
 	struct skcipher_walk walk;
@@ -61,7 +61,7 @@ static int ecb_crypt(struct skcipher_req
 		u8 *wsrc = walk.src.virt.addr;
 		u8 *wdst = walk.dst.virt.addr;
 
-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
 
 		/* Process multi-block batch */
 		if (nbytes >= bsize * CAST5_PARALLEL_BLOCKS) {
@@ -90,10 +90,9 @@ static int ecb_crypt(struct skcipher_req
 		} while (nbytes >= bsize);
 
 done:
+		cast5_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-
-	cast5_fpu_end(fpu_enabled);
 	return err;
 }
 
@@ -197,7 +196,7 @@ static int cbc_decrypt(struct skcipher_r
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	struct skcipher_walk walk;
 	unsigned int nbytes;
 	int err;
@@ -205,12 +204,11 @@ static int cbc_decrypt(struct skcipher_r
 	err = skcipher_walk_virt(&walk, req, false);
 
 	while ((nbytes = walk.nbytes)) {
-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
 		nbytes = __cbc_decrypt(ctx, &walk);
+		cast5_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-
-	cast5_fpu_end(fpu_enabled);
 	return err;
 }
 
@@ -277,7 +275,7 @@ static int ctr_crypt(struct skcipher_req
 {
 	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
 	struct cast5_ctx *ctx = crypto_skcipher_ctx(tfm);
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	struct skcipher_walk walk;
 	unsigned int nbytes;
 	int err;
@@ -285,13 +283,12 @@ static int ctr_crypt(struct skcipher_req
 	err = skcipher_walk_virt(&walk, req, false);
 
 	while ((nbytes = walk.nbytes) >= CAST5_BLOCK_SIZE) {
-		fpu_enabled = cast5_fpu_begin(fpu_enabled, &walk, nbytes);
+		fpu_enabled = cast5_fpu_begin(false, &walk, nbytes);
 		nbytes = __ctr_crypt(&walk, ctx);
+		cast5_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 
-	cast5_fpu_end(fpu_enabled);
-
 	if (walk.nbytes) {
 		ctr_crypt_final(&walk, ctx);
 		err = skcipher_walk_done(&walk, 0);
Index: linux-5.4.5-rt3/arch/x86/crypto/chacha_glue.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/crypto/chacha_glue.c
+++ linux-5.4.5-rt3/arch/x86/crypto/chacha_glue.c
@@ -127,7 +127,6 @@ static int chacha_simd_stream_xor(struct
 				  const struct chacha_ctx *ctx, const u8 *iv)
 {
 	u32 *state, state_buf[16 + 2] __aligned(8);
-	int next_yield = 4096; /* bytes until next FPU yield */
 	int err = 0;
 
 	BUILD_BUG_ON(CHACHA_STATE_ALIGN != 16);
@@ -140,20 +139,14 @@ static int chacha_simd_stream_xor(struct
 
 		if (nbytes < walk->total) {
 			nbytes = round_down(nbytes, walk->stride);
-			next_yield -= nbytes;
 		}
 
 		chacha_dosimd(state, walk->dst.virt.addr, walk->src.virt.addr,
 			      nbytes, ctx->nrounds);
 
-		if (next_yield <= 0) {
-			/* temporarily allow preemption */
-			kernel_fpu_end();
-			kernel_fpu_begin();
-			next_yield = 4096;
-		}
-
+		kernel_fpu_end();
 		err = skcipher_walk_done(walk, walk->nbytes - nbytes);
+		kernel_fpu_begin();
 	}
 
 	return err;
Index: linux-5.4.5-rt3/arch/x86/crypto/glue_helper.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/crypto/glue_helper.c
+++ linux-5.4.5-rt3/arch/x86/crypto/glue_helper.c
@@ -24,7 +24,7 @@ int glue_ecb_req_128bit(const struct com
 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	const unsigned int bsize = 128 / 8;
 	struct skcipher_walk walk;
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	unsigned int nbytes;
 	int err;
 
@@ -37,7 +37,7 @@ int glue_ecb_req_128bit(const struct com
 		unsigned int i;
 
 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
-					     &walk, fpu_enabled, nbytes);
+					     &walk, false, nbytes);
 		for (i = 0; i < gctx->num_funcs; i++) {
 			func_bytes = bsize * gctx->funcs[i].num_blocks;
 
@@ -55,10 +55,9 @@ int glue_ecb_req_128bit(const struct com
 			if (nbytes < bsize)
 				break;
 		}
+		glue_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
-
-	glue_fpu_end(fpu_enabled);
 	return err;
 }
 EXPORT_SYMBOL_GPL(glue_ecb_req_128bit);
@@ -101,7 +100,7 @@ int glue_cbc_decrypt_req_128bit(const st
 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	const unsigned int bsize = 128 / 8;
 	struct skcipher_walk walk;
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	unsigned int nbytes;
 	int err;
 
@@ -115,7 +114,7 @@ int glue_cbc_decrypt_req_128bit(const st
 		u128 last_iv;
 
 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
-					     &walk, fpu_enabled, nbytes);
+					     &walk, false, nbytes);
 		/* Start of the last block. */
 		src += nbytes / bsize - 1;
 		dst += nbytes / bsize - 1;
@@ -147,10 +146,10 @@ int glue_cbc_decrypt_req_128bit(const st
 done:
 		u128_xor(dst, dst, (u128 *)walk.iv);
 		*(u128 *)walk.iv = last_iv;
+		glue_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 
-	glue_fpu_end(fpu_enabled);
 	return err;
 }
 EXPORT_SYMBOL_GPL(glue_cbc_decrypt_req_128bit);
@@ -161,7 +160,7 @@ int glue_ctr_req_128bit(const struct com
 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));
 	const unsigned int bsize = 128 / 8;
 	struct skcipher_walk walk;
-	bool fpu_enabled = false;
+	bool fpu_enabled;
 	unsigned int nbytes;
 	int err;
 
@@ -175,7 +174,7 @@ int glue_ctr_req_128bit(const struct com
 		le128 ctrblk;
 
 		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
-					     &walk, fpu_enabled, nbytes);
+					     &walk, false, nbytes);
 
 		be128_to_le128(&ctrblk, (be128 *)walk.iv);
 
@@ -199,11 +198,10 @@ int glue_ctr_req_128bit(const struct com
 		}
 
 		le128_to_be128((be128 *)walk.iv, &ctrblk);
+		glue_fpu_end(fpu_enabled);
 		err = skcipher_walk_done(&walk, nbytes);
 	}
 
-	glue_fpu_end(fpu_enabled);
-
 	if (nbytes) {
 		le128 ctrblk;
 		u128 tmp;
@@ -301,8 +299,14 @@ int glue_xts_req_128bit(const struct com
 	tweak_fn(tweak_ctx, walk.iv, walk.iv);
 
 	while (nbytes) {
+		fpu_enabled = glue_fpu_begin(bsize, gctx->fpu_blocks_limit,
+					     &walk, fpu_enabled,
+					     nbytes < bsize ? bsize : nbytes);
 		nbytes = __glue_xts_req_128bit(gctx, crypt_ctx, &walk);
 
+		glue_fpu_end(fpu_enabled);
+		fpu_enabled = false;
+
 		err = skcipher_walk_done(&walk, nbytes);
 		nbytes = walk.nbytes;
 	}
Index: linux-5.4.5-rt3/arch/x86/entry/common.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/entry/common.c
+++ linux-5.4.5-rt3/arch/x86/entry/common.c
@@ -130,7 +130,7 @@ static long syscall_trace_enter(struct p
 
 #define EXIT_TO_USERMODE_LOOP_FLAGS				\
 	(_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_UPROBE |	\
-	 _TIF_NEED_RESCHED | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING)
+	 _TIF_NEED_RESCHED_MASK | _TIF_USER_RETURN_NOTIFY | _TIF_PATCH_PENDING)
 
 static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
 {
@@ -145,9 +145,16 @@ static void exit_to_usermode_loop(struct
 		/* We have work to do. */
 		local_irq_enable();
 
-		if (cached_flags & _TIF_NEED_RESCHED)
+		if (cached_flags & _TIF_NEED_RESCHED_MASK)
 			schedule();
 
+#ifdef ARCH_RT_DELAYS_SIGNAL_SEND
+		if (unlikely(current->forced_info.si_signo)) {
+			struct task_struct *t = current;
+			force_sig_info(&t->forced_info);
+			t->forced_info.si_signo = 0;
+		}
+#endif
 		if (cached_flags & _TIF_UPROBE)
 			uprobe_notify_resume(regs);
 
Index: linux-5.4.5-rt3/arch/x86/entry/entry_32.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/entry/entry_32.S
+++ linux-5.4.5-rt3/arch/x86/entry/entry_32.S
@@ -1106,8 +1106,26 @@ restore_all:
 restore_all_kernel:
 #ifdef CONFIG_PREEMPTION
 	DISABLE_INTERRUPTS(CLBR_ANY)
+	# preempt count == 0 + NEED_RS set?
 	cmpl	$0, PER_CPU_VAR(__preempt_count)
+#ifndef CONFIG_PREEMPT_LAZY
 	jnz	.Lno_preempt
+#else
+	jz	test_int_off
+
+	# atleast preempt count == 0 ?
+	cmpl	$_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
+	jne	.Lno_preempt
+
+	movl	PER_CPU_VAR(current_task), %ebp
+	cmpl	$0,TASK_TI_preempt_lazy_count(%ebp)	# non-zero preempt_lazy_count ?
+	jnz	.Lno_preempt
+
+	testl	$_TIF_NEED_RESCHED_LAZY, TASK_TI_flags(%ebp)
+	jz	.Lno_preempt
+
+test_int_off:
+#endif
 	testl	$X86_EFLAGS_IF, PT_EFLAGS(%esp)	# interrupts off (exception path) ?
 	jz	.Lno_preempt
 	call	preempt_schedule_irq
Index: linux-5.4.5-rt3/arch/x86/entry/entry_64.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/entry/entry_64.S
+++ linux-5.4.5-rt3/arch/x86/entry/entry_64.S
@@ -670,7 +670,23 @@ retint_kernel:
 	btl	$9, EFLAGS(%rsp)		/* were interrupts off? */
 	jnc	1f
 	cmpl	$0, PER_CPU_VAR(__preempt_count)
+#ifndef CONFIG_PREEMPT_LAZY
 	jnz	1f
+#else
+	jz	do_preempt_schedule_irq
+
+	# atleast preempt count == 0 ?
+	cmpl	$_PREEMPT_ENABLED,PER_CPU_VAR(__preempt_count)
+	jnz	1f
+
+	movq	PER_CPU_VAR(current_task), %rcx
+	cmpl	$0, TASK_TI_preempt_lazy_count(%rcx)
+	jnz	1f
+
+	btl	$TIF_NEED_RESCHED_LAZY,TASK_TI_flags(%rcx)
+	jnc	1f
+do_preempt_schedule_irq:
+#endif
 	call	preempt_schedule_irq
 1:
 #endif
@@ -1074,6 +1090,7 @@ EXPORT_SYMBOL(native_load_gs_index)
 	jmp	2b
 	.previous
 
+#ifndef CONFIG_PREEMPT_RT
 /* Call softirq on interrupt stack. Interrupts are off. */
 ENTRY(do_softirq_own_stack)
 	pushq	%rbp
@@ -1084,6 +1101,7 @@ ENTRY(do_softirq_own_stack)
 	leaveq
 	ret
 ENDPROC(do_softirq_own_stack)
+#endif
 
 #ifdef CONFIG_XEN_PV
 idtentry hypervisor_callback xen_do_hypervisor_callback has_error_code=0
Index: linux-5.4.5-rt3/arch/x86/include/asm/fpu/api.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/include/asm/fpu/api.h
+++ linux-5.4.5-rt3/arch/x86/include/asm/fpu/api.h
@@ -23,6 +23,7 @@ extern void kernel_fpu_begin(void);
 extern void kernel_fpu_end(void);
 extern bool irq_fpu_usable(void);
 extern void fpregs_mark_activate(void);
+extern void kernel_fpu_resched(void);
 
 /*
  * Use fpregs_lock() while editing CPU's FPU registers or fpu->state.
Index: linux-5.4.5-rt3/arch/x86/include/asm/preempt.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/include/asm/preempt.h
+++ linux-5.4.5-rt3/arch/x86/include/asm/preempt.h
@@ -89,17 +89,48 @@ static __always_inline void __preempt_co
  * a decrement which hits zero means we have no preempt_count and should
  * reschedule.
  */
-static __always_inline bool __preempt_count_dec_and_test(void)
+static __always_inline bool ____preempt_count_dec_and_test(void)
 {
 	return GEN_UNARY_RMWcc("decl", __preempt_count, e, __percpu_arg([var]));
 }
 
+static __always_inline bool __preempt_count_dec_and_test(void)
+{
+	if (____preempt_count_dec_and_test())
+		return true;
+#ifdef CONFIG_PREEMPT_LAZY
+	if (preempt_count())
+		return false;
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
+	return false;
+#endif
+}
+
 /*
  * Returns true when we need to resched and can (barring IRQ state).
  */
 static __always_inline bool should_resched(int preempt_offset)
 {
+#ifdef CONFIG_PREEMPT_LAZY
+	u32 tmp;
+	tmp = raw_cpu_read_4(__preempt_count);
+	if (tmp == preempt_offset)
+		return true;
+
+	/* preempt count == 0 ? */
+	tmp &= ~PREEMPT_NEED_RESCHED;
+	if (tmp != preempt_offset)
+		return false;
+	/* XXX PREEMPT_LOCK_OFFSET */
+	if (current_thread_info()->preempt_lazy_count)
+		return false;
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+#else
 	return unlikely(raw_cpu_read_4(__preempt_count) == preempt_offset);
+#endif
 }
 
 #ifdef CONFIG_PREEMPTION
Index: linux-5.4.5-rt3/arch/x86/include/asm/signal.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/include/asm/signal.h
+++ linux-5.4.5-rt3/arch/x86/include/asm/signal.h
@@ -28,6 +28,19 @@ typedef struct {
 #define SA_IA32_ABI	0x02000000u
 #define SA_X32_ABI	0x01000000u
 
+/*
+ * Because some traps use the IST stack, we must keep preemption
+ * disabled while calling do_trap(), but do_trap() may call
+ * force_sig_info() which will grab the signal spin_locks for the
+ * task, which in PREEMPT_RT are mutexes.  By defining
+ * ARCH_RT_DELAYS_SIGNAL_SEND the force_sig_info() will set
+ * TIF_NOTIFY_RESUME and set up the signal to be sent on exit of the
+ * trap.
+ */
+#if defined(CONFIG_PREEMPT_RT)
+#define ARCH_RT_DELAYS_SIGNAL_SEND
+#endif
+
 #ifndef CONFIG_COMPAT
 typedef sigset_t compat_sigset_t;
 #endif
Index: linux-5.4.5-rt3/arch/x86/include/asm/stackprotector.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/include/asm/stackprotector.h
+++ linux-5.4.5-rt3/arch/x86/include/asm/stackprotector.h
@@ -60,7 +60,7 @@
  */
 static __always_inline void boot_init_stack_canary(void)
 {
-	u64 canary;
+	u64 uninitialized_var(canary);
 	u64 tsc;
 
 #ifdef CONFIG_X86_64
@@ -71,8 +71,14 @@ static __always_inline void boot_init_st
 	 * of randomness. The TSC only matters for very early init,
 	 * there it already has some randomness on most systems. Later
 	 * on during the bootup the random pool has true entropy too.
+	 * For preempt-rt we need to weaken the randomness a bit, as
+	 * we can't call into the random generator from atomic context
+	 * due to locking constraints. We just leave canary
+	 * uninitialized and use the TSC based randomness on top of it.
 	 */
+#ifndef CONFIG_PREEMPT_RT
 	get_random_bytes(&canary, sizeof(canary));
+#endif
 	tsc = rdtsc();
 	canary += tsc + (tsc << 32UL);
 	canary &= CANARY_MASK;
Index: linux-5.4.5-rt3/arch/x86/include/asm/thread_info.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/include/asm/thread_info.h
+++ linux-5.4.5-rt3/arch/x86/include/asm/thread_info.h
@@ -56,17 +56,24 @@ struct task_struct;
 struct thread_info {
 	unsigned long		flags;		/* low level flags */
 	u32			status;		/* thread synchronous flags */
+	int			preempt_lazy_count;	/* 0 => lazy preemptable
+							  <0 => BUG */
 };
 
 #define INIT_THREAD_INFO(tsk)			\
 {						\
 	.flags		= 0,			\
+	.preempt_lazy_count = 0,		\
 }
 
 #else /* !__ASSEMBLY__ */
 
 #include <asm/asm-offsets.h>
 
+#define GET_THREAD_INFO(reg) \
+	_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
+	_ASM_SUB $(THREAD_SIZE),reg ;
+
 #endif
 
 /*
@@ -92,6 +99,7 @@ struct thread_info {
 #define TIF_NOCPUID		15	/* CPUID is not accessible in userland */
 #define TIF_NOTSC		16	/* TSC is not accessible in userland */
 #define TIF_IA32		17	/* IA32 compatibility process */
+#define TIF_NEED_RESCHED_LAZY	18	/* lazy rescheduling necessary */
 #define TIF_NOHZ		19	/* in adaptive nohz mode */
 #define TIF_MEMDIE		20	/* is terminating due to OOM killer */
 #define TIF_POLLING_NRFLAG	21	/* idle is polling for TIF_NEED_RESCHED */
@@ -122,6 +130,7 @@ struct thread_info {
 #define _TIF_NOCPUID		(1 << TIF_NOCPUID)
 #define _TIF_NOTSC		(1 << TIF_NOTSC)
 #define _TIF_IA32		(1 << TIF_IA32)
+#define _TIF_NEED_RESCHED_LAZY	(1 << TIF_NEED_RESCHED_LAZY)
 #define _TIF_NOHZ		(1 << TIF_NOHZ)
 #define _TIF_POLLING_NRFLAG	(1 << TIF_POLLING_NRFLAG)
 #define _TIF_IO_BITMAP		(1 << TIF_IO_BITMAP)
@@ -159,6 +168,8 @@ struct thread_info {
 #define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW|_TIF_USER_RETURN_NOTIFY)
 #define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
 
+#define _TIF_NEED_RESCHED_MASK	(_TIF_NEED_RESCHED | _TIF_NEED_RESCHED_LAZY)
+
 #define STACK_WARN		(THREAD_SIZE/8)
 
 /*
Index: linux-5.4.5-rt3/arch/x86/kernel/apic/io_apic.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-5.4.5-rt3/arch/x86/kernel/apic/io_apic.c
@@ -1725,7 +1725,7 @@ static bool io_apic_level_ack_pending(st
 	return false;
 }
 
-static inline bool ioapic_irqd_mask(struct irq_data *data)
+static inline bool ioapic_prepare_move(struct irq_data *data)
 {
 	/* If we are moving the IRQ we need to mask it */
 	if (unlikely(irqd_is_setaffinity_pending(data))) {
@@ -1736,9 +1736,9 @@ static inline bool ioapic_irqd_mask(stru
 	return false;
 }
 
-static inline void ioapic_irqd_unmask(struct irq_data *data, bool masked)
+static inline void ioapic_finish_move(struct irq_data *data, bool moveit)
 {
-	if (unlikely(masked)) {
+	if (unlikely(moveit)) {
 		/* Only migrate the irq if the ack has been received.
 		 *
 		 * On rare occasions the broadcast level triggered ack gets
@@ -1773,11 +1773,11 @@ static inline void ioapic_irqd_unmask(st
 	}
 }
 #else
-static inline bool ioapic_irqd_mask(struct irq_data *data)
+static inline bool ioapic_prepare_move(struct irq_data *data)
 {
 	return false;
 }
-static inline void ioapic_irqd_unmask(struct irq_data *data, bool masked)
+static inline void ioapic_finish_move(struct irq_data *data, bool moveit)
 {
 }
 #endif
@@ -1786,11 +1786,11 @@ static void ioapic_ack_level(struct irq_
 {
 	struct irq_cfg *cfg = irqd_cfg(irq_data);
 	unsigned long v;
-	bool masked;
+	bool moveit;
 	int i;
 
 	irq_complete_move(cfg);
-	masked = ioapic_irqd_mask(irq_data);
+	moveit = ioapic_prepare_move(irq_data);
 
 	/*
 	 * It appears there is an erratum which affects at least version 0x11
@@ -1845,7 +1845,7 @@ static void ioapic_ack_level(struct irq_
 		eoi_ioapic_pin(cfg->vector, irq_data->chip_data);
 	}
 
-	ioapic_irqd_unmask(irq_data, masked);
+	ioapic_finish_move(irq_data, moveit);
 }
 
 static void ioapic_ir_ack_level(struct irq_data *irq_data)
Index: linux-5.4.5-rt3/arch/x86/kernel/asm-offsets.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kernel/asm-offsets.c
+++ linux-5.4.5-rt3/arch/x86/kernel/asm-offsets.c
@@ -38,6 +38,10 @@ static void __used common(void)
 #endif
 
 	BLANK();
+#ifdef CONFIG_PREEMPT_LAZY
+	OFFSET(TASK_TI_flags, task_struct, thread_info.flags);
+	OFFSET(TASK_TI_preempt_lazy_count, task_struct, thread_info.preempt_lazy_count);
+#endif
 	OFFSET(TASK_addr_limit, task_struct, thread.addr_limit);
 
 	BLANK();
@@ -92,6 +96,7 @@ static void __used common(void)
 
 	BLANK();
 	DEFINE(PTREGS_SIZE, sizeof(struct pt_regs));
+	DEFINE(_PREEMPT_ENABLED, PREEMPT_ENABLED);
 
 	/* TLB state for the entry code */
 	OFFSET(TLB_STATE_user_pcid_flush_mask, tlb_state, user_pcid_flush_mask);
Index: linux-5.4.5-rt3/arch/x86/kernel/cpu/mshyperv.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kernel/cpu/mshyperv.c
+++ linux-5.4.5-rt3/arch/x86/kernel/cpu/mshyperv.c
@@ -77,12 +77,13 @@ EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
 __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
 {
 	struct pt_regs *old_regs = set_irq_regs(regs);
+	u64 ip = regs ? instruction_pointer(regs) : 0;
 
 	entering_irq();
 	inc_irq_stat(hyperv_stimer0_count);
 	if (hv_stimer0_handler)
 		hv_stimer0_handler();
-	add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0);
+	add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0, ip);
 	ack_APIC_irq();
 
 	exiting_irq();
Index: linux-5.4.5-rt3/arch/x86/kernel/fpu/core.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kernel/fpu/core.c
+++ linux-5.4.5-rt3/arch/x86/kernel/fpu/core.c
@@ -113,6 +113,18 @@ void kernel_fpu_end(void)
 }
 EXPORT_SYMBOL_GPL(kernel_fpu_end);
 
+void kernel_fpu_resched(void)
+{
+	WARN_ON_FPU(!this_cpu_read(in_kernel_fpu));
+
+	if (should_resched(PREEMPT_OFFSET)) {
+		kernel_fpu_end();
+		cond_resched();
+		kernel_fpu_begin();
+	}
+}
+EXPORT_SYMBOL_GPL(kernel_fpu_resched);
+
 /*
  * Save the FPU state (mark it for reload if necessary):
  *
Index: linux-5.4.5-rt3/arch/x86/kernel/irq_32.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kernel/irq_32.c
+++ linux-5.4.5-rt3/arch/x86/kernel/irq_32.c
@@ -131,6 +131,7 @@ int irq_init_percpu_irqstack(unsigned in
 	return 0;
 }
 
+#ifndef CONFIG_PREEMPT_RT
 void do_softirq_own_stack(void)
 {
 	struct irq_stack *irqstk;
@@ -147,6 +148,7 @@ void do_softirq_own_stack(void)
 
 	call_on_stack(__do_softirq, isp);
 }
+#endif
 
 void handle_irq(struct irq_desc *desc, struct pt_regs *regs)
 {
Index: linux-5.4.5-rt3/arch/x86/kernel/process_32.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kernel/process_32.c
+++ linux-5.4.5-rt3/arch/x86/kernel/process_32.c
@@ -38,6 +38,7 @@
 #include <linux/io.h>
 #include <linux/kdebug.h>
 #include <linux/syscalls.h>
+#include <linux/highmem.h>
 
 #include <asm/pgtable.h>
 #include <asm/ldt.h>
@@ -196,6 +197,35 @@ start_thread(struct pt_regs *regs, unsig
 }
 EXPORT_SYMBOL_GPL(start_thread);
 
+#ifdef CONFIG_PREEMPT_RT
+static void switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p)
+{
+	int i;
+
+	/*
+	 * Clear @prev's kmap_atomic mappings
+	 */
+	for (i = 0; i < prev_p->kmap_idx; i++) {
+		int idx = i + KM_TYPE_NR * smp_processor_id();
+		pte_t *ptep = kmap_pte - idx;
+
+		kpte_clear_flush(ptep, __fix_to_virt(FIX_KMAP_BEGIN + idx));
+	}
+	/*
+	 * Restore @next_p's kmap_atomic mappings
+	 */
+	for (i = 0; i < next_p->kmap_idx; i++) {
+		int idx = i + KM_TYPE_NR * smp_processor_id();
+
+		if (!pte_none(next_p->kmap_pte[i]))
+			set_pte(kmap_pte - idx, next_p->kmap_pte[i]);
+	}
+}
+#else
+static inline void
+switch_kmaps(struct task_struct *prev_p, struct task_struct *next_p) { }
+#endif
+
 
 /*
  *	switch_to(x,y) should switch tasks from x to y.
@@ -266,6 +296,8 @@ __switch_to(struct task_struct *prev_p,
 
 	switch_to_extra(prev_p, next_p);
 
+	switch_kmaps(prev_p, next_p);
+
 	/*
 	 * Leave lazy mode, flushing any hypercalls made here.
 	 * This must be done before restoring TLS segments so
Index: linux-5.4.5-rt3/arch/x86/kvm/x86.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/kvm/x86.c
+++ linux-5.4.5-rt3/arch/x86/kvm/x86.c
@@ -7207,6 +7207,14 @@ int kvm_arch_init(void *opaque)
 		goto out;
 	}
 
+#ifdef CONFIG_PREEMPT_RT
+	if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC)) {
+		pr_err("RT requires X86_FEATURE_CONSTANT_TSC\n");
+		r = -EOPNOTSUPP;
+		goto out;
+	}
+#endif
+
 	r = -ENOMEM;
 	x86_fpu_cache = kmem_cache_create("x86_fpu", sizeof(struct fpu),
 					  __alignof__(struct fpu), SLAB_ACCOUNT,
Index: linux-5.4.5-rt3/arch/x86/mm/highmem_32.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/mm/highmem_32.c
+++ linux-5.4.5-rt3/arch/x86/mm/highmem_32.c
@@ -33,10 +33,11 @@ EXPORT_SYMBOL(kunmap);
  */
 void *kmap_atomic_prot(struct page *page, pgprot_t prot)
 {
+	pte_t pte = mk_pte(page, prot);
 	unsigned long vaddr;
 	int idx, type;
 
-	preempt_disable();
+	preempt_disable_nort();
 	pagefault_disable();
 
 	if (!PageHighMem(page))
@@ -46,7 +47,10 @@ void *kmap_atomic_prot(struct page *page
 	idx = type + KM_TYPE_NR*smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 	BUG_ON(!pte_none(*(kmap_pte-idx)));
-	set_pte(kmap_pte-idx, mk_pte(page, prot));
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_pte(kmap_pte-idx, pte);
 	arch_flush_lazy_mmu_mode();
 
 	return (void *)vaddr;
@@ -89,6 +93,9 @@ void __kunmap_atomic(void *kvaddr)
 		 * is a bad idea also, in case the page changes cacheability
 		 * attributes or becomes a protected page in a hypervisor.
 		 */
+#ifdef CONFIG_PREEMPT_RT
+		current->kmap_pte[type] = __pte(0);
+#endif
 		kpte_clear_flush(kmap_pte-idx, vaddr);
 		kmap_atomic_idx_pop();
 		arch_flush_lazy_mmu_mode();
@@ -101,7 +108,7 @@ void __kunmap_atomic(void *kvaddr)
 #endif
 
 	pagefault_enable();
-	preempt_enable();
+	preempt_enable_nort();
 }
 EXPORT_SYMBOL(__kunmap_atomic);
 
Index: linux-5.4.5-rt3/arch/x86/mm/iomap_32.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/mm/iomap_32.c
+++ linux-5.4.5-rt3/arch/x86/mm/iomap_32.c
@@ -46,6 +46,7 @@ EXPORT_SYMBOL_GPL(iomap_free);
 
 void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot)
 {
+	pte_t pte = pfn_pte(pfn, prot);
 	unsigned long vaddr;
 	int idx, type;
 
@@ -55,7 +56,12 @@ void *kmap_atomic_prot_pfn(unsigned long
 	type = kmap_atomic_idx_push();
 	idx = type + KM_TYPE_NR * smp_processor_id();
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
-	set_pte(kmap_pte - idx, pfn_pte(pfn, prot));
+	WARN_ON(!pte_none(*(kmap_pte - idx)));
+
+#ifdef CONFIG_PREEMPT_RT
+	current->kmap_pte[type] = pte;
+#endif
+	set_pte(kmap_pte - idx, pte);
 	arch_flush_lazy_mmu_mode();
 
 	return (void *)vaddr;
@@ -106,6 +112,9 @@ iounmap_atomic(void __iomem *kvaddr)
 		 * is a bad idea also, in case the page changes cacheability
 		 * attributes or becomes a protected page in a hypervisor.
 		 */
+#ifdef CONFIG_PREEMPT_RT
+		current->kmap_pte[type] = __pte(0);
+#endif
 		kpte_clear_flush(kmap_pte-idx, vaddr);
 		kmap_atomic_idx_pop();
 	}
Index: linux-5.4.5-rt3/arch/x86/mm/tlb.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/x86/mm/tlb.c
+++ linux-5.4.5-rt3/arch/x86/mm/tlb.c
@@ -708,7 +708,7 @@ void native_flush_tlb_others(const struc
 			       (void *)info, 1);
 	else
 		on_each_cpu_cond_mask(tlb_is_not_lazy, flush_tlb_func_remote,
-				(void *)info, 1, GFP_ATOMIC, cpumask);
+				(void *)info, 1, cpumask);
 }
 
 /*
Index: linux-5.4.5-rt3/arch/xtensa/include/asm/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/arch/xtensa/include/asm/spinlock_types.h
+++ linux-5.4.5-rt3/arch/xtensa/include/asm/spinlock_types.h
@@ -2,10 +2,6 @@
 #ifndef __ASM_SPINLOCK_TYPES_H
 #define __ASM_SPINLOCK_TYPES_H
 
-#if !defined(__LINUX_SPINLOCK_TYPES_H) && !defined(__ASM_SPINLOCK_H)
-# error "please don't include this file directly"
-#endif
-
 #include <asm-generic/qspinlock_types.h>
 #include <asm-generic/qrwlock_types.h>
 
Index: linux-5.4.5-rt3/arch/xtensa/kernel/entry.S
===================================================================
--- linux-5.4.5-rt3.orig/arch/xtensa/kernel/entry.S
+++ linux-5.4.5-rt3/arch/xtensa/kernel/entry.S
@@ -520,7 +520,7 @@ common_exception_return:
 	call4	schedule	# void schedule (void)
 	j	1b
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 6:
 	_bbci.l	a4, TIF_NEED_RESCHED, 4f
 
Index: linux-5.4.5-rt3/arch/xtensa/kernel/traps.c
===================================================================
--- linux-5.4.5-rt3.orig/arch/xtensa/kernel/traps.c
+++ linux-5.4.5-rt3/arch/xtensa/kernel/traps.c
@@ -524,12 +524,15 @@ DEFINE_SPINLOCK(die_lock);
 void die(const char * str, struct pt_regs * regs, long err)
 {
 	static int die_counter;
+	const char *pr = "";
+
+	if (IS_ENABLED(CONFIG_PREEMPTION))
+		pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
 
 	console_verbose();
 	spin_lock_irq(&die_lock);
 
-	pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter,
-		IS_ENABLED(CONFIG_PREEMPT) ? " PREEMPT" : "");
+	pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter, pr);
 	show_regs(regs);
 	if (!user_mode(regs))
 		show_stack(NULL, (unsigned long*)regs->areg[1]);
Index: linux-5.4.5-rt3/block/blk-ioc.c
===================================================================
--- linux-5.4.5-rt3.orig/block/blk-ioc.c
+++ linux-5.4.5-rt3/block/blk-ioc.c
@@ -9,6 +9,7 @@
 #include <linux/blkdev.h>
 #include <linux/slab.h>
 #include <linux/sched/task.h>
+#include <linux/delay.h>
 
 #include "blk.h"
 
@@ -115,7 +116,7 @@ static void ioc_release_fn(struct work_s
 			spin_unlock(&q->queue_lock);
 		} else {
 			spin_unlock_irqrestore(&ioc->lock, flags);
-			cpu_relax();
+			cpu_chill();
 			spin_lock_irqsave_nested(&ioc->lock, flags, 1);
 		}
 	}
Index: linux-5.4.5-rt3/block/blk-mq.c
===================================================================
--- linux-5.4.5-rt3.orig/block/blk-mq.c
+++ linux-5.4.5-rt3/block/blk-mq.c
@@ -611,9 +611,17 @@ static void __blk_mq_complete_request(st
 		return;
 	}
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
+	/*
+	 * Avoid SMP function calls for completions because they acquire
+	 * sleeping spinlocks on RT.
+	 */
+#ifdef CONFIG_PREEMPT_RT
+	shared = true;
+#else
 	if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags))
 		shared = cpus_share_cache(cpu, ctx->cpu);
+#endif
 
 	if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) {
 		rq->csd.func = __blk_mq_complete_request_remote;
@@ -623,7 +631,7 @@ static void __blk_mq_complete_request(st
 	} else {
 		q->mq_ops->complete(rq);
 	}
-	put_cpu();
+	put_cpu_light();
 }
 
 static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx)
@@ -1466,14 +1474,14 @@ static void __blk_mq_delay_run_hw_queue(
 		return;
 
 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
-		int cpu = get_cpu();
+		int cpu = get_cpu_light();
 		if (cpumask_test_cpu(cpu, hctx->cpumask)) {
 			__blk_mq_run_hw_queue(hctx);
-			put_cpu();
+			put_cpu_light();
 			return;
 		}
 
-		put_cpu();
+		put_cpu_light();
 	}
 
 	kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
Index: linux-5.4.5-rt3/block/blk-softirq.c
===================================================================
--- linux-5.4.5-rt3.orig/block/blk-softirq.c
+++ linux-5.4.5-rt3/block/blk-softirq.c
@@ -42,17 +42,13 @@ static __latent_entropy void blk_done_so
 static void trigger_softirq(void *data)
 {
 	struct request *rq = data;
-	unsigned long flags;
 	struct list_head *list;
 
-	local_irq_save(flags);
 	list = this_cpu_ptr(&blk_cpu_done);
 	list_add_tail(&rq->ipi_list, list);
 
 	if (list->next == &rq->ipi_list)
 		raise_softirq_irqoff(BLOCK_SOFTIRQ);
-
-	local_irq_restore(flags);
 }
 
 /*
@@ -91,6 +87,7 @@ static int blk_softirq_cpu_dead(unsigned
 			 this_cpu_ptr(&blk_cpu_done));
 	raise_softirq_irqoff(BLOCK_SOFTIRQ);
 	local_irq_enable();
+	preempt_check_resched_rt();
 
 	return 0;
 }
@@ -142,6 +139,7 @@ do_local:
 		goto do_local;
 
 	local_irq_restore(flags);
+	preempt_check_resched_rt();
 }
 
 static __init int blk_softirq_init(void)
Index: linux-5.4.5-rt3/crypto/cryptd.c
===================================================================
--- linux-5.4.5-rt3.orig/crypto/cryptd.c
+++ linux-5.4.5-rt3/crypto/cryptd.c
@@ -36,6 +36,7 @@ static struct workqueue_struct *cryptd_w
 struct cryptd_cpu_queue {
 	struct crypto_queue queue;
 	struct work_struct work;
+	spinlock_t qlock;
 };
 
 struct cryptd_queue {
@@ -105,6 +106,7 @@ static int cryptd_init_queue(struct cryp
 		cpu_queue = per_cpu_ptr(queue->cpu_queue, cpu);
 		crypto_init_queue(&cpu_queue->queue, max_cpu_qlen);
 		INIT_WORK(&cpu_queue->work, cryptd_queue_worker);
+		spin_lock_init(&cpu_queue->qlock);
 	}
 	pr_info("cryptd: max_cpu_qlen set to %d\n", max_cpu_qlen);
 	return 0;
@@ -129,8 +131,10 @@ static int cryptd_enqueue_request(struct
 	struct cryptd_cpu_queue *cpu_queue;
 	refcount_t *refcnt;
 
-	cpu = get_cpu();
-	cpu_queue = this_cpu_ptr(queue->cpu_queue);
+	cpu_queue = raw_cpu_ptr(queue->cpu_queue);
+	spin_lock_bh(&cpu_queue->qlock);
+	cpu = smp_processor_id();
+
 	err = crypto_enqueue_request(&cpu_queue->queue, request);
 
 	refcnt = crypto_tfm_ctx(request->tfm);
@@ -146,7 +150,7 @@ static int cryptd_enqueue_request(struct
 	refcount_inc(refcnt);
 
 out_put_cpu:
-	put_cpu();
+	spin_unlock_bh(&cpu_queue->qlock);
 
 	return err;
 }
@@ -162,16 +166,11 @@ static void cryptd_queue_worker(struct w
 	cpu_queue = container_of(work, struct cryptd_cpu_queue, work);
 	/*
 	 * Only handle one request at a time to avoid hogging crypto workqueue.
-	 * preempt_disable/enable is used to prevent being preempted by
-	 * cryptd_enqueue_request(). local_bh_disable/enable is used to prevent
-	 * cryptd_enqueue_request() being accessed from software interrupts.
 	 */
-	local_bh_disable();
-	preempt_disable();
+	spin_lock_bh(&cpu_queue->qlock);
 	backlog = crypto_get_backlog(&cpu_queue->queue);
 	req = crypto_dequeue_request(&cpu_queue->queue);
-	preempt_enable();
-	local_bh_enable();
+	spin_unlock_bh(&cpu_queue->qlock);
 
 	if (!req)
 		return;
Index: linux-5.4.5-rt3/drivers/block/zram/zcomp.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/block/zram/zcomp.c
+++ linux-5.4.5-rt3/drivers/block/zram/zcomp.c
@@ -113,12 +113,20 @@ ssize_t zcomp_available_show(const char
 
 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
 {
-	return *get_cpu_ptr(comp->stream);
+	struct zcomp_strm *zstrm;
+
+	zstrm = *get_local_ptr(comp->stream);
+	spin_lock(&zstrm->zcomp_lock);
+	return zstrm;
 }
 
 void zcomp_stream_put(struct zcomp *comp)
 {
-	put_cpu_ptr(comp->stream);
+	struct zcomp_strm *zstrm;
+
+	zstrm = *this_cpu_ptr(comp->stream);
+	spin_unlock(&zstrm->zcomp_lock);
+	put_local_ptr(zstrm);
 }
 
 int zcomp_compress(struct zcomp_strm *zstrm,
@@ -168,6 +176,7 @@ int zcomp_cpu_up_prepare(unsigned int cp
 		pr_err("Can't allocate a compression stream\n");
 		return -ENOMEM;
 	}
+	spin_lock_init(&zstrm->zcomp_lock);
 	*per_cpu_ptr(comp->stream, cpu) = zstrm;
 	return 0;
 }
Index: linux-5.4.5-rt3/drivers/block/zram/zcomp.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/block/zram/zcomp.h
+++ linux-5.4.5-rt3/drivers/block/zram/zcomp.h
@@ -10,6 +10,7 @@ struct zcomp_strm {
 	/* compression/decompression buffer */
 	void *buffer;
 	struct crypto_comp *tfm;
+	spinlock_t zcomp_lock;
 };
 
 /* dynamic per-device compression frontend */
Index: linux-5.4.5-rt3/drivers/block/zram/zram_drv.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/block/zram/zram_drv.c
+++ linux-5.4.5-rt3/drivers/block/zram/zram_drv.c
@@ -55,6 +55,40 @@ static void zram_free_page(struct zram *
 static int zram_bvec_read(struct zram *zram, struct bio_vec *bvec,
 				u32 index, int offset, struct bio *bio);
 
+#ifdef CONFIG_PREEMPT_RT
+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages)
+{
+	size_t index;
+
+	for (index = 0; index < num_pages; index++)
+		spin_lock_init(&zram->table[index].lock);
+}
+
+static int zram_slot_trylock(struct zram *zram, u32 index)
+{
+	int ret;
+
+	ret = spin_trylock(&zram->table[index].lock);
+	if (ret)
+		__set_bit(ZRAM_LOCK, &zram->table[index].flags);
+	return ret;
+}
+
+static void zram_slot_lock(struct zram *zram, u32 index)
+{
+	spin_lock(&zram->table[index].lock);
+	__set_bit(ZRAM_LOCK, &zram->table[index].flags);
+}
+
+static void zram_slot_unlock(struct zram *zram, u32 index)
+{
+	__clear_bit(ZRAM_LOCK, &zram->table[index].flags);
+	spin_unlock(&zram->table[index].lock);
+}
+
+#else
+
+static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
 
 static int zram_slot_trylock(struct zram *zram, u32 index)
 {
@@ -70,6 +104,7 @@ static void zram_slot_unlock(struct zram
 {
 	bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
 }
+#endif
 
 static inline bool init_done(struct zram *zram)
 {
@@ -1155,6 +1190,7 @@ static bool zram_meta_alloc(struct zram
 
 	if (!huge_class_size)
 		huge_class_size = zs_huge_class_size(zram->mem_pool);
+	zram_meta_init_table_locks(zram, num_pages);
 	return true;
 }
 
@@ -1217,6 +1253,7 @@ static int __zram_bvec_read(struct zram
 	unsigned long handle;
 	unsigned int size;
 	void *src, *dst;
+	struct zcomp_strm *zstrm;
 
 	zram_slot_lock(zram, index);
 	if (zram_test_flag(zram, index, ZRAM_WB)) {
@@ -1247,6 +1284,7 @@ static int __zram_bvec_read(struct zram
 
 	size = zram_get_obj_size(zram, index);
 
+	zstrm = zcomp_stream_get(zram->comp);
 	src = zs_map_object(zram->mem_pool, handle, ZS_MM_RO);
 	if (size == PAGE_SIZE) {
 		dst = kmap_atomic(page);
@@ -1254,14 +1292,13 @@ static int __zram_bvec_read(struct zram
 		kunmap_atomic(dst);
 		ret = 0;
 	} else {
-		struct zcomp_strm *zstrm = zcomp_stream_get(zram->comp);
 
 		dst = kmap_atomic(page);
 		ret = zcomp_decompress(zstrm, src, size, dst);
 		kunmap_atomic(dst);
-		zcomp_stream_put(zram->comp);
 	}
 	zs_unmap_object(zram->mem_pool, handle);
+	zcomp_stream_put(zram->comp);
 	zram_slot_unlock(zram, index);
 
 	/* Should NEVER happen. Return bio error if it does. */
Index: linux-5.4.5-rt3/drivers/block/zram/zram_drv.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/block/zram/zram_drv.h
+++ linux-5.4.5-rt3/drivers/block/zram/zram_drv.h
@@ -63,6 +63,7 @@ struct zram_table_entry {
 		unsigned long element;
 	};
 	unsigned long flags;
+	spinlock_t lock;
 #ifdef CONFIG_ZRAM_MEMORY_TRACKING
 	ktime_t ac_time;
 #endif
Index: linux-5.4.5-rt3/drivers/char/random.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/char/random.c
+++ linux-5.4.5-rt3/drivers/char/random.c
@@ -1305,28 +1305,27 @@ static __u32 get_reg(struct fast_pool *f
 	return *ptr;
 }
 
-void add_interrupt_randomness(int irq, int irq_flags)
+void add_interrupt_randomness(int irq, int irq_flags, __u64 ip)
 {
 	struct entropy_store	*r;
 	struct fast_pool	*fast_pool = this_cpu_ptr(&irq_randomness);
-	struct pt_regs		*regs = get_irq_regs();
 	unsigned long		now = jiffies;
 	cycles_t		cycles = random_get_entropy();
 	__u32			c_high, j_high;
-	__u64			ip;
 	unsigned long		seed;
 	int			credit = 0;
 
 	if (cycles == 0)
-		cycles = get_reg(fast_pool, regs);
+		cycles = get_reg(fast_pool, NULL);
 	c_high = (sizeof(cycles) > 4) ? cycles >> 32 : 0;
 	j_high = (sizeof(now) > 4) ? now >> 32 : 0;
 	fast_pool->pool[0] ^= cycles ^ j_high ^ irq;
 	fast_pool->pool[1] ^= now ^ c_high;
-	ip = regs ? instruction_pointer(regs) : _RET_IP_;
+	if (!ip)
+		ip = _RET_IP_;
 	fast_pool->pool[2] ^= ip;
 	fast_pool->pool[3] ^= (sizeof(ip) > 4) ? ip >> 32 :
-		get_reg(fast_pool, regs);
+		get_reg(fast_pool, NULL);
 
 	fast_mix(fast_pool);
 	add_interrupt_bench(cycles);
Index: linux-5.4.5-rt3/drivers/char/tpm/tpm-dev-common.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/char/tpm/tpm-dev-common.c
+++ linux-5.4.5-rt3/drivers/char/tpm/tpm-dev-common.c
@@ -20,7 +20,6 @@
 #include "tpm-dev.h"
 
 static struct workqueue_struct *tpm_dev_wq;
-static DEFINE_MUTEX(tpm_dev_wq_lock);
 
 static ssize_t tpm_dev_transmit(struct tpm_chip *chip, struct tpm_space *space,
 				u8 *buf, size_t bufsiz)
Index: linux-5.4.5-rt3/drivers/char/tpm/tpm_tis.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/char/tpm/tpm_tis.c
+++ linux-5.4.5-rt3/drivers/char/tpm/tpm_tis.c
@@ -49,6 +49,31 @@ static inline struct tpm_tis_tcg_phy *to
 	return container_of(data, struct tpm_tis_tcg_phy, priv);
 }
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * Flushes previous write operations to chip so that a subsequent
+ * ioread*()s won't stall a cpu.
+ */
+static inline void tpm_tis_flush(void __iomem *iobase)
+{
+	ioread8(iobase + TPM_ACCESS(0));
+}
+#else
+#define tpm_tis_flush(iobase) do { } while (0)
+#endif
+
+static inline void tpm_tis_iowrite8(u8 b, void __iomem *iobase, u32 addr)
+{
+	iowrite8(b, iobase + addr);
+	tpm_tis_flush(iobase);
+}
+
+static inline void tpm_tis_iowrite32(u32 b, void __iomem *iobase, u32 addr)
+{
+	iowrite32(b, iobase + addr);
+	tpm_tis_flush(iobase);
+}
+
 static bool interrupts = true;
 module_param(interrupts, bool, 0444);
 MODULE_PARM_DESC(interrupts, "Enable interrupts");
@@ -146,7 +171,7 @@ static int tpm_tcg_write_bytes(struct tp
 	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
 
 	while (len--)
-		iowrite8(*value++, phy->iobase + addr);
+		tpm_tis_iowrite8(*value++, phy->iobase, addr);
 
 	return 0;
 }
@@ -173,7 +198,7 @@ static int tpm_tcg_write32(struct tpm_ti
 {
 	struct tpm_tis_tcg_phy *phy = to_tpm_tis_tcg_phy(data);
 
-	iowrite32(value, phy->iobase + addr);
+	tpm_tis_iowrite32(value, phy->iobase, addr);
 
 	return 0;
 }
Index: linux-5.4.5-rt3/drivers/clocksource/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/drivers/clocksource/Kconfig
+++ linux-5.4.5-rt3/drivers/clocksource/Kconfig
@@ -434,6 +434,13 @@ config ATMEL_TCB_CLKSRC
 	help
 	  Support for Timer Counter Blocks on Atmel SoCs.
 
+config ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
+	bool "TC Block use 32 KiHz clock"
+	depends on ATMEL_TCB_CLKSRC
+	default y
+	help
+	  Select this to use 32 KiHz base clock rate as TC block clock.
+
 config CLKSRC_EXYNOS_MCT
 	bool "Exynos multi core timer driver" if COMPILE_TEST
 	depends on ARM || ARM64
Index: linux-5.4.5-rt3/drivers/clocksource/timer-atmel-tcb.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/clocksource/timer-atmel-tcb.c
+++ linux-5.4.5-rt3/drivers/clocksource/timer-atmel-tcb.c
@@ -28,8 +28,7 @@
  *     this 32 bit free-running counter. the second channel is not used.
  *
  *   - The third channel may be used to provide a 16-bit clockevent
- *     source, used in either periodic or oneshot mode.  This runs
- *     at 32 KiHZ, and can handle delays of up to two seconds.
+ *     source, used in either periodic or oneshot mode.
  *
  * REVISIT behavior during system suspend states... we should disable
  * all clocks and save the power.  Easily done for clockevent devices,
@@ -143,6 +142,8 @@ static unsigned long notrace tc_delay_ti
 struct tc_clkevt_device {
 	struct clock_event_device	clkevt;
 	struct clk			*clk;
+	bool				clk_enabled;
+	u32				freq;
 	void __iomem			*regs;
 };
 
@@ -151,15 +152,26 @@ static struct tc_clkevt_device *to_tc_cl
 	return container_of(clkevt, struct tc_clkevt_device, clkevt);
 }
 
-/* For now, we always use the 32K clock ... this optimizes for NO_HZ,
- * because using one of the divided clocks would usually mean the
- * tick rate can never be less than several dozen Hz (vs 0.5 Hz).
- *
- * A divided clock could be good for high resolution timers, since
- * 30.5 usec resolution can seem "low".
- */
 static u32 timer_clock;
 
+static void tc_clk_disable(struct clock_event_device *d)
+{
+	struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+
+	clk_disable(tcd->clk);
+	tcd->clk_enabled = false;
+}
+
+static void tc_clk_enable(struct clock_event_device *d)
+{
+	struct tc_clkevt_device *tcd = to_tc_clkevt(d);
+
+	if (tcd->clk_enabled)
+		return;
+	clk_enable(tcd->clk);
+	tcd->clk_enabled = true;
+}
+
 static int tc_shutdown(struct clock_event_device *d)
 {
 	struct tc_clkevt_device *tcd = to_tc_clkevt(d);
@@ -167,8 +179,14 @@ static int tc_shutdown(struct clock_even
 
 	writel(0xff, regs + ATMEL_TC_REG(2, IDR));
 	writel(ATMEL_TC_CLKDIS, regs + ATMEL_TC_REG(2, CCR));
+	return 0;
+}
+
+static int tc_shutdown_clk_off(struct clock_event_device *d)
+{
+	tc_shutdown(d);
 	if (!clockevent_state_detached(d))
-		clk_disable(tcd->clk);
+		tc_clk_disable(d);
 
 	return 0;
 }
@@ -181,9 +199,9 @@ static int tc_set_oneshot(struct clock_e
 	if (clockevent_state_oneshot(d) || clockevent_state_periodic(d))
 		tc_shutdown(d);
 
-	clk_enable(tcd->clk);
+	tc_clk_enable(d);
 
-	/* slow clock, count up to RC, then irq and stop */
+	/* count up to RC, then irq and stop */
 	writel(timer_clock | ATMEL_TC_CPCSTOP | ATMEL_TC_WAVE |
 		     ATMEL_TC_WAVESEL_UP_AUTO, regs + ATMEL_TC_REG(2, CMR));
 	writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
@@ -203,12 +221,12 @@ static int tc_set_periodic(struct clock_
 	/* By not making the gentime core emulate periodic mode on top
 	 * of oneshot, we get lower overhead and improved accuracy.
 	 */
-	clk_enable(tcd->clk);
+	tc_clk_enable(d);
 
-	/* slow clock, count up to RC, then irq and restart */
+	/* count up to RC, then irq and restart */
 	writel(timer_clock | ATMEL_TC_WAVE | ATMEL_TC_WAVESEL_UP_AUTO,
 		     regs + ATMEL_TC_REG(2, CMR));
-	writel((32768 + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
+	writel((tcd->freq + HZ / 2) / HZ, tcaddr + ATMEL_TC_REG(2, RC));
 
 	/* Enable clock and interrupts on RC compare */
 	writel(ATMEL_TC_CPCS, regs + ATMEL_TC_REG(2, IER));
@@ -234,9 +252,13 @@ static struct tc_clkevt_device clkevt =
 		.features		= CLOCK_EVT_FEAT_PERIODIC |
 					  CLOCK_EVT_FEAT_ONESHOT,
 		/* Should be lower than at91rm9200's system timer */
+#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
 		.rating			= 125,
+#else
+		.rating			= 200,
+#endif
 		.set_next_event		= tc_next_event,
-		.set_state_shutdown	= tc_shutdown,
+		.set_state_shutdown	= tc_shutdown_clk_off,
 		.set_state_periodic	= tc_set_periodic,
 		.set_state_oneshot	= tc_set_oneshot,
 	},
@@ -256,8 +278,11 @@ static irqreturn_t ch2_irq(int irq, void
 	return IRQ_NONE;
 }
 
-static int __init setup_clkevents(struct atmel_tc *tc, int clk32k_divisor_idx)
+static const u8 atmel_tcb_divisors[5] = { 2, 8, 32, 128, 0, };
+
+static int __init setup_clkevents(struct atmel_tc *tc, int divisor_idx)
 {
+	unsigned divisor = atmel_tcb_divisors[divisor_idx];
 	int ret;
 	struct clk *t2_clk = tc->clk[2];
 	int irq = tc->irq[2];
@@ -278,7 +303,11 @@ static int __init setup_clkevents(struct
 	clkevt.regs = tc->regs;
 	clkevt.clk = t2_clk;
 
-	timer_clock = clk32k_divisor_idx;
+	timer_clock = divisor_idx;
+	if (!divisor)
+		clkevt.freq = 32768;
+	else
+		clkevt.freq = clk_get_rate(t2_clk) / divisor;
 
 	clkevt.clkevt.cpumask = cpumask_of(0);
 
@@ -289,7 +318,7 @@ static int __init setup_clkevents(struct
 		return ret;
 	}
 
-	clockevents_config_and_register(&clkevt.clkevt, 32768, 1, 0xffff);
+	clockevents_config_and_register(&clkevt.clkevt, clkevt.freq, 1, 0xffff);
 
 	return ret;
 }
@@ -346,8 +375,6 @@ static void __init tcb_setup_single_chan
 	writel(ATMEL_TC_SYNC, tcaddr + ATMEL_TC_BCR);
 }
 
-static const u8 atmel_tcb_divisors[5] = { 2, 8, 32, 128, 0, };
-
 static const struct of_device_id atmel_tcb_of_match[] = {
 	{ .compatible = "atmel,at91rm9200-tcb", .data = (void *)16, },
 	{ .compatible = "atmel,at91sam9x5-tcb", .data = (void *)32, },
@@ -467,7 +494,11 @@ static int __init tcb_clksrc_init(struct
 		goto err_disable_t1;
 
 	/* channel 2:  periodic and oneshot timer support */
+#ifdef CONFIG_ATMEL_TCB_CLKSRC_USE_SLOW_CLOCK
 	ret = setup_clkevents(&tc, clk32k_divisor_idx);
+#else
+	ret = setup_clkevents(&tc, best_divisor_idx);
+#endif
 	if (ret)
 		goto err_unregister_clksrc;
 
Index: linux-5.4.5-rt3/drivers/connector/cn_proc.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/connector/cn_proc.c
+++ linux-5.4.5-rt3/drivers/connector/cn_proc.c
@@ -18,6 +18,7 @@
 #include <linux/pid_namespace.h>
 
 #include <linux/cn_proc.h>
+#include <linux/locallock.h>
 
 /*
  * Size of a cn_msg followed by a proc_event structure.  Since the
@@ -40,10 +41,11 @@ static struct cb_id cn_proc_event_id = {
 
 /* proc_event_counts is used as the sequence number of the netlink message */
 static DEFINE_PER_CPU(__u32, proc_event_counts) = { 0 };
+static DEFINE_LOCAL_IRQ_LOCK(send_msg_lock);
 
 static inline void send_msg(struct cn_msg *msg)
 {
-	preempt_disable();
+	local_lock(send_msg_lock);
 
 	msg->seq = __this_cpu_inc_return(proc_event_counts) - 1;
 	((struct proc_event *)msg->data)->cpu = smp_processor_id();
@@ -56,7 +58,7 @@ static inline void send_msg(struct cn_ms
 	 */
 	cn_netlink_send(msg, 0, CN_IDX_PROC, GFP_NOWAIT);
 
-	preempt_enable();
+	local_unlock(send_msg_lock);
 }
 
 void proc_fork_connector(struct task_struct *task)
Index: linux-5.4.5-rt3/drivers/dma-buf/dma-buf.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/dma-buf/dma-buf.c
+++ linux-5.4.5-rt3/drivers/dma-buf/dma-buf.c
@@ -214,7 +214,7 @@ static __poll_t dma_buf_poll(struct file
 		return 0;
 
 retry:
-	seq = read_seqcount_begin(&resv->seq);
+	seq = read_seqbegin(&resv->seq);
 	rcu_read_lock();
 
 	fobj = rcu_dereference(resv->fence);
@@ -223,7 +223,7 @@ retry:
 	else
 		shared_count = 0;
 	fence_excl = rcu_dereference(resv->fence_excl);
-	if (read_seqcount_retry(&resv->seq, seq)) {
+	if (read_seqretry(&resv->seq, seq)) {
 		rcu_read_unlock();
 		goto retry;
 	}
@@ -1189,12 +1189,12 @@ static int dma_buf_debug_show(struct seq
 
 		robj = buf_obj->resv;
 		while (true) {
-			seq = read_seqcount_begin(&robj->seq);
+			seq = read_seqbegin(&robj->seq);
 			rcu_read_lock();
 			fobj = rcu_dereference(robj->fence);
 			shared_count = fobj ? fobj->shared_count : 0;
 			fence = rcu_dereference(robj->fence_excl);
-			if (!read_seqcount_retry(&robj->seq, seq))
+			if (!read_seqretry(&robj->seq, seq))
 				break;
 			rcu_read_unlock();
 		}
Index: linux-5.4.5-rt3/drivers/dma-buf/dma-resv.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/dma-buf/dma-resv.c
+++ linux-5.4.5-rt3/drivers/dma-buf/dma-resv.c
@@ -49,12 +49,6 @@
 DEFINE_WD_CLASS(reservation_ww_class);
 EXPORT_SYMBOL(reservation_ww_class);
 
-struct lock_class_key reservation_seqcount_class;
-EXPORT_SYMBOL(reservation_seqcount_class);
-
-const char reservation_seqcount_string[] = "reservation_seqcount";
-EXPORT_SYMBOL(reservation_seqcount_string);
-
 /**
  * dma_resv_list_alloc - allocate fence list
  * @shared_max: number of fences we need space for
@@ -103,8 +97,7 @@ void dma_resv_init(struct dma_resv *obj)
 {
 	ww_mutex_init(&obj->lock, &reservation_ww_class);
 
-	__seqcount_init(&obj->seq, reservation_seqcount_string,
-			&reservation_seqcount_class);
+	seqlock_init(&obj->seq);
 	RCU_INIT_POINTER(obj->fence, NULL);
 	RCU_INIT_POINTER(obj->fence_excl, NULL);
 }
@@ -234,8 +227,7 @@ void dma_resv_add_shared_fence(struct dm
 	fobj = dma_resv_get_list(obj);
 	count = fobj->shared_count;
 
-	preempt_disable();
-	write_seqcount_begin(&obj->seq);
+	write_seqlock(&obj->seq);
 
 	for (i = 0; i < count; ++i) {
 
@@ -255,8 +247,7 @@ replace:
 	/* pointer update must be visible before we extend the shared_count */
 	smp_store_mb(fobj->shared_count, count);
 
-	write_seqcount_end(&obj->seq);
-	preempt_enable();
+	write_sequnlock(&obj->seq);
 	dma_fence_put(old);
 }
 EXPORT_SYMBOL(dma_resv_add_shared_fence);
@@ -283,14 +274,12 @@ void dma_resv_add_excl_fence(struct dma_
 	if (fence)
 		dma_fence_get(fence);
 
-	preempt_disable();
-	write_seqcount_begin(&obj->seq);
-	/* write_seqcount_begin provides the necessary memory barrier */
+	write_seqlock(&obj->seq);
+	/* write_seqlock provides the necessary memory barrier */
 	RCU_INIT_POINTER(obj->fence_excl, fence);
 	if (old)
 		old->shared_count = 0;
-	write_seqcount_end(&obj->seq);
-	preempt_enable();
+	write_sequnlock(&obj->seq);
 
 	/* inplace update, no shared fences */
 	while (i--)
@@ -368,13 +357,11 @@ retry:
 	src_list = dma_resv_get_list(dst);
 	old = dma_resv_get_excl(dst);
 
-	preempt_disable();
-	write_seqcount_begin(&dst->seq);
-	/* write_seqcount_begin provides the necessary memory barrier */
+	write_seqlock(&dst->seq);
+	/* write_seqlock provides the necessary memory barrier */
 	RCU_INIT_POINTER(dst->fence_excl, new);
 	RCU_INIT_POINTER(dst->fence, dst_list);
-	write_seqcount_end(&dst->seq);
-	preempt_enable();
+	write_sequnlock(&dst->seq);
 
 	dma_resv_list_free(src_list);
 	dma_fence_put(old);
@@ -414,7 +401,7 @@ int dma_resv_get_fences_rcu(struct dma_r
 		shared_count = i = 0;
 
 		rcu_read_lock();
-		seq = read_seqcount_begin(&obj->seq);
+		seq = read_seqbegin(&obj->seq);
 
 		fence_excl = rcu_dereference(obj->fence_excl);
 		if (fence_excl && !dma_fence_get_rcu(fence_excl))
@@ -456,7 +443,7 @@ int dma_resv_get_fences_rcu(struct dma_r
 			}
 		}
 
-		if (i != shared_count || read_seqcount_retry(&obj->seq, seq)) {
+		if (i != shared_count || read_seqretry(&obj->seq, seq)) {
 			while (i--)
 				dma_fence_put(shared[i]);
 			dma_fence_put(fence_excl);
@@ -507,7 +494,7 @@ long dma_resv_wait_timeout_rcu(struct dm
 
 retry:
 	shared_count = 0;
-	seq = read_seqcount_begin(&obj->seq);
+	seq = read_seqbegin(&obj->seq);
 	rcu_read_lock();
 	i = -1;
 
@@ -553,7 +540,7 @@ retry:
 
 	rcu_read_unlock();
 	if (fence) {
-		if (read_seqcount_retry(&obj->seq, seq)) {
+		if (read_seqretry(&obj->seq, seq)) {
 			dma_fence_put(fence);
 			goto retry;
 		}
@@ -607,7 +594,7 @@ bool dma_resv_test_signaled_rcu(struct d
 retry:
 	ret = true;
 	shared_count = 0;
-	seq = read_seqcount_begin(&obj->seq);
+	seq = read_seqbegin(&obj->seq);
 
 	if (test_all) {
 		unsigned i;
@@ -627,7 +614,7 @@ retry:
 				break;
 		}
 
-		if (read_seqcount_retry(&obj->seq, seq))
+		if (read_seqretry(&obj->seq, seq))
 			goto retry;
 	}
 
@@ -639,7 +626,7 @@ retry:
 			if (ret < 0)
 				goto retry;
 
-			if (read_seqcount_retry(&obj->seq, seq))
+			if (read_seqretry(&obj->seq, seq))
 				goto retry;
 		}
 	}
Index: linux-5.4.5-rt3/drivers/firmware/efi/efi.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/firmware/efi/efi.c
+++ linux-5.4.5-rt3/drivers/firmware/efi/efi.c
@@ -68,7 +68,7 @@ struct mm_struct efi_mm = {
 
 struct workqueue_struct *efi_rts_wq;
 
-static bool disable_runtime;
+static bool disable_runtime = IS_ENABLED(CONFIG_PREEMPT_RT);
 static int __init setup_noefi(char *arg)
 {
 	disable_runtime = true;
@@ -94,6 +94,9 @@ static int __init parse_efi_cmdline(char
 	if (parse_option_str(str, "noruntime"))
 		disable_runtime = true;
 
+	if (parse_option_str(str, "runtime"))
+		disable_runtime = false;
+
 	return 0;
 }
 early_param("efi", parse_efi_cmdline);
Index: linux-5.4.5-rt3/drivers/gpu/drm/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/Kconfig
+++ linux-5.4.5-rt3/drivers/gpu/drm/Kconfig
@@ -397,7 +397,7 @@ config DRM_R128
 
 config DRM_I810
 	tristate "Intel I810"
-	# !PREEMPT because of missing ioctl locking
+	# !PREEMPTION because of missing ioctl locking
 	depends on DRM && AGP && AGP_INTEL && (!PREEMPTION || BROKEN)
 	help
 	  Choose this option if you have an Intel I810 graphics card.  If M is
Index: linux-5.4.5-rt3/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -252,11 +252,9 @@ static int amdgpu_amdkfd_remove_eviction
 	new->shared_count = k;
 
 	/* Install the new fence list, seqcount provides the barriers */
-	preempt_disable();
-	write_seqcount_begin(&resv->seq);
+	write_seqlock(&resv->seq);
 	RCU_INIT_POINTER(resv->fence, new);
-	write_seqcount_end(&resv->seq);
-	preempt_enable();
+	write_sequnlock(&resv->seq);
 
 	/* Drop the references to the removed fences or move them to ef_list */
 	for (i = j, k = 0; i < old->shared_count; ++i) {
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/display/intel_sprite.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/display/intel_sprite.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/display/intel_sprite.c
@@ -38,6 +38,7 @@
 #include <drm/drm_plane_helper.h>
 #include <drm/drm_rect.h>
 #include <drm/i915_drm.h>
+#include <linux/locallock.h>
 
 #include "i915_drv.h"
 #include "i915_trace.h"
@@ -80,6 +81,8 @@ int intel_usecs_to_scanlines(const struc
 #define VBLANK_EVASION_TIME_US 100
 #endif
 
+static DEFINE_LOCAL_IRQ_LOCK(pipe_update_lock);
+
 /**
  * intel_pipe_update_start() - start update of a set of display registers
  * @new_crtc_state: the new crtc state
@@ -129,7 +132,7 @@ void intel_pipe_update_start(const struc
 		DRM_ERROR("PSR idle timed out 0x%x, atomic update may fail\n",
 			  psr_status);
 
-	local_irq_disable();
+	local_lock_irq(pipe_update_lock);
 
 	crtc->debug.min_vbl = min;
 	crtc->debug.max_vbl = max;
@@ -153,11 +156,11 @@ void intel_pipe_update_start(const struc
 			break;
 		}
 
-		local_irq_enable();
+		local_unlock_irq(pipe_update_lock);
 
 		timeout = schedule_timeout(timeout);
 
-		local_irq_disable();
+		local_lock_irq(pipe_update_lock);
 	}
 
 	finish_wait(wq, &wait);
@@ -190,7 +193,7 @@ void intel_pipe_update_start(const struc
 	return;
 
 irq_disable:
-	local_irq_disable();
+	local_lock_irq(pipe_update_lock);
 }
 
 /**
@@ -226,7 +229,7 @@ void intel_pipe_update_end(struct intel_
 		new_crtc_state->base.event = NULL;
 	}
 
-	local_irq_enable();
+	local_unlock_irq(pipe_update_lock);
 
 	if (intel_vgpu_active(dev_priv))
 		return;
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/gem/i915_gem_busy.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/gem/i915_gem_busy.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/gem/i915_gem_busy.c
@@ -75,7 +75,6 @@ busy_check_writer(const struct dma_fence
 
 	return __busy_set_if_active(fence, __busy_write_id);
 }
-
 int
 i915_gem_busy_ioctl(struct drm_device *dev, void *data,
 		    struct drm_file *file)
@@ -110,7 +109,8 @@ i915_gem_busy_ioctl(struct drm_device *d
 	 *
 	 */
 retry:
-	seq = raw_read_seqcount(&obj->base.resv->seq);
+	/* XXX raw_read_seqcount() does not wait for the WRTIE to finish */
+	seq = read_seqbegin(&obj->base.resv->seq);
 
 	/* Translate the exclusive fence to the READ *and* WRITE engine */
 	args->busy =
@@ -129,7 +129,7 @@ retry:
 		}
 	}
 
-	if (args->busy && read_seqcount_retry(&obj->base.resv->seq, seq))
+	if (args->busy && read_seqretry(&obj->base.resv->seq, seq))
 		goto retry;
 
 	err = 0;
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -120,7 +120,6 @@ __dma_fence_signal__notify(struct dma_fe
 	struct dma_fence_cb *cur, *tmp;
 
 	lockdep_assert_held(fence->lock);
-	lockdep_assert_irqs_disabled();
 
 	list_for_each_entry_safe(cur, tmp, list, node) {
 		INIT_LIST_HEAD(&cur->node);
@@ -134,9 +133,10 @@ void intel_engine_breadcrumbs_irq(struct
 	const ktime_t timestamp = ktime_get();
 	struct intel_context *ce, *cn;
 	struct list_head *pos, *next;
+	unsigned long flags;
 	LIST_HEAD(signal);
 
-	spin_lock(&b->irq_lock);
+	spin_lock_irqsave(&b->irq_lock, flags);
 
 	if (b->irq_armed && list_empty(&b->signalers))
 		__intel_breadcrumbs_disarm_irq(b);
@@ -182,30 +182,23 @@ void intel_engine_breadcrumbs_irq(struct
 		}
 	}
 
-	spin_unlock(&b->irq_lock);
+	spin_unlock_irqrestore(&b->irq_lock, flags);
 
 	list_for_each_safe(pos, next, &signal) {
 		struct i915_request *rq =
 			list_entry(pos, typeof(*rq), signal_link);
 		struct list_head cb_list;
 
-		spin_lock(&rq->lock);
+		spin_lock_irqsave(&rq->lock, flags);
 		list_replace(&rq->fence.cb_list, &cb_list);
 		__dma_fence_signal__timestamp(&rq->fence, timestamp);
 		__dma_fence_signal__notify(&rq->fence, &cb_list);
-		spin_unlock(&rq->lock);
+		spin_unlock_irqrestore(&rq->lock, flags);
 
 		i915_request_put(rq);
 	}
 }
 
-void intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine)
-{
-	local_irq_disable();
-	intel_engine_breadcrumbs_irq(engine);
-	local_irq_enable();
-}
-
 static void signal_irq_work(struct irq_work *work)
 {
 	struct intel_engine_cs *engine =
@@ -275,7 +268,6 @@ void intel_engine_fini_breadcrumbs(struc
 bool i915_request_enable_breadcrumb(struct i915_request *rq)
 {
 	lockdep_assert_held(&rq->lock);
-	lockdep_assert_irqs_disabled();
 
 	if (test_bit(I915_FENCE_FLAG_ACTIVE, &rq->fence.flags)) {
 		struct intel_breadcrumbs *b = &rq->engine->breadcrumbs;
@@ -325,7 +317,6 @@ void i915_request_cancel_breadcrumb(stru
 	struct intel_breadcrumbs *b = &rq->engine->breadcrumbs;
 
 	lockdep_assert_held(&rq->lock);
-	lockdep_assert_irqs_disabled();
 
 	/*
 	 * We must wait for b->irq_lock so that we know the interrupt handler
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_engine.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/gt/intel_engine.h
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_engine.h
@@ -349,7 +349,6 @@ void intel_engine_init_execlists(struct
 void intel_engine_init_breadcrumbs(struct intel_engine_cs *engine);
 void intel_engine_fini_breadcrumbs(struct intel_engine_cs *engine);
 
-void intel_engine_signal_breadcrumbs(struct intel_engine_cs *engine);
 void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine);
 
 static inline void
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_hangcheck.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/gt/intel_hangcheck.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_hangcheck.c
@@ -283,7 +283,7 @@ static void hangcheck_elapsed(struct wor
 	for_each_engine(engine, gt->i915, id) {
 		struct hangcheck hc;
 
-		intel_engine_signal_breadcrumbs(engine);
+		intel_engine_breadcrumbs_irq(engine);
 
 		hangcheck_load_sample(engine, &hc);
 		hangcheck_accumulate_sample(engine, &hc);
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_reset.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/gt/intel_reset.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/gt/intel_reset.c
@@ -695,7 +695,7 @@ static void reset_finish_engine(struct i
 	engine->reset.finish(engine);
 	intel_uncore_forcewake_put(engine->uncore, FORCEWAKE_ALL);
 
-	intel_engine_signal_breadcrumbs(engine);
+	intel_engine_breadcrumbs_irq(engine);
 }
 
 static void reset_finish(struct intel_gt *gt, intel_engine_mask_t awake)
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/i915_irq.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/i915_irq.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/i915_irq.c
@@ -983,6 +983,7 @@ bool i915_get_crtc_scanoutpos(struct drm
 	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
 
 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_disable_rt();
 
 	/* Get optional system timestamp before query. */
 	if (stime)
@@ -1034,6 +1035,7 @@ bool i915_get_crtc_scanoutpos(struct drm
 		*etime = ktime_get();
 
 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_enable_rt();
 
 	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
 
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/i915_request.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/i915_request.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/i915_request.c
@@ -205,14 +205,14 @@ static void remove_from_engine(struct i9
 	 * check that the rq still belongs to the newly locked engine.
 	 */
 	locked = READ_ONCE(rq->engine);
-	spin_lock(&locked->active.lock);
+	spin_lock_irq(&locked->active.lock);
 	while (unlikely(locked != (engine = READ_ONCE(rq->engine)))) {
 		spin_unlock(&locked->active.lock);
 		spin_lock(&engine->active.lock);
 		locked = engine;
 	}
 	list_del(&rq->sched.link);
-	spin_unlock(&locked->active.lock);
+	spin_unlock_irq(&locked->active.lock);
 }
 
 static bool i915_request_retire(struct i915_request *rq)
@@ -272,8 +272,6 @@ static bool i915_request_retire(struct i
 		active->retire(active, rq);
 	}
 
-	local_irq_disable();
-
 	/*
 	 * We only loosely track inflight requests across preemption,
 	 * and so we may find ourselves attempting to retire a _completed_
@@ -282,7 +280,7 @@ static bool i915_request_retire(struct i
 	 */
 	remove_from_engine(rq);
 
-	spin_lock(&rq->lock);
+	spin_lock_irq(&rq->lock);
 	i915_request_mark_complete(rq);
 	if (!i915_request_signaled(rq))
 		dma_fence_signal_locked(&rq->fence);
@@ -297,9 +295,7 @@ static bool i915_request_retire(struct i
 		__notify_execute_cb(rq);
 	}
 	GEM_BUG_ON(!list_empty(&rq->execute_cb));
-	spin_unlock(&rq->lock);
-
-	local_irq_enable();
+	spin_unlock_irq(&rq->lock);
 
 	remove_from_client(rq);
 	list_del(&rq->link);
Index: linux-5.4.5-rt3/drivers/gpu/drm/i915/i915_trace.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/i915/i915_trace.h
+++ linux-5.4.5-rt3/drivers/gpu/drm/i915/i915_trace.h
@@ -2,6 +2,10 @@
 #if !defined(_I915_TRACE_H_) || defined(TRACE_HEADER_MULTI_READ)
 #define _I915_TRACE_H_
 
+#ifdef CONFIG_PREEMPT_RT
+#define NOTRACE
+#endif
+
 #include <linux/stringify.h>
 #include <linux/types.h>
 #include <linux/tracepoint.h>
@@ -721,7 +725,7 @@ DEFINE_EVENT(i915_request, i915_request_
 	    TP_ARGS(rq)
 );
 
-#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS)
+#if defined(CONFIG_DRM_I915_LOW_LEVEL_TRACEPOINTS) && !defined(NOTRACE)
 DEFINE_EVENT(i915_request, i915_request_submit,
 	     TP_PROTO(struct i915_request *rq),
 	     TP_ARGS(rq)
Index: linux-5.4.5-rt3/drivers/gpu/drm/radeon/radeon_display.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/gpu/drm/radeon/radeon_display.c
+++ linux-5.4.5-rt3/drivers/gpu/drm/radeon/radeon_display.c
@@ -1819,6 +1819,7 @@ int radeon_get_crtc_scanoutpos(struct dr
 	struct radeon_device *rdev = dev->dev_private;
 
 	/* preempt_disable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_disable_rt();
 
 	/* Get optional system timestamp before query. */
 	if (stime)
@@ -1911,6 +1912,7 @@ int radeon_get_crtc_scanoutpos(struct dr
 		*etime = ktime_get();
 
 	/* preempt_enable_rt() should go right here in PREEMPT_RT patchset. */
+	preempt_enable_rt();
 
 	/* Decode into vertical and horizontal scanout position. */
 	*vpos = position & 0x1fff;
Index: linux-5.4.5-rt3/drivers/hv/hyperv_vmbus.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/hv/hyperv_vmbus.h
+++ linux-5.4.5-rt3/drivers/hv/hyperv_vmbus.h
@@ -18,6 +18,7 @@
 #include <linux/atomic.h>
 #include <linux/hyperv.h>
 #include <linux/interrupt.h>
+#include <linux/irq.h>
 
 #include "hv_trace.h"
 
Index: linux-5.4.5-rt3/drivers/hv/vmbus_drv.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/hv/vmbus_drv.c
+++ linux-5.4.5-rt3/drivers/hv/vmbus_drv.c
@@ -22,6 +22,7 @@
 #include <linux/clockchips.h>
 #include <linux/cpu.h>
 #include <linux/sched/task_stack.h>
+#include <linux/irq.h>
 
 #include <asm/mshyperv.h>
 #include <linux/delay.h>
@@ -1199,6 +1200,8 @@ static void vmbus_isr(void)
 	void *page_addr = hv_cpu->synic_event_page;
 	struct hv_message *msg;
 	union hv_synic_event_flags *event;
+	struct pt_regs *regs = get_irq_regs();
+	u64 ip = regs ? instruction_pointer(regs) : 0;
 	bool handled = false;
 
 	if (unlikely(page_addr == NULL))
@@ -1243,7 +1246,7 @@ static void vmbus_isr(void)
 			tasklet_schedule(&hv_cpu->msg_dpc);
 	}
 
-	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0);
+	add_interrupt_randomness(HYPERVISOR_CALLBACK_VECTOR, 0, ip);
 }
 
 /*
Index: linux-5.4.5-rt3/drivers/leds/trigger/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/drivers/leds/trigger/Kconfig
+++ linux-5.4.5-rt3/drivers/leds/trigger/Kconfig
@@ -64,6 +64,7 @@ config LEDS_TRIGGER_BACKLIGHT
 
 config LEDS_TRIGGER_CPU
 	bool "LED CPU Trigger"
+	depends on !PREEMPT_RT
 	help
 	  This allows LEDs to be controlled by active CPUs. This shows
 	  the active CPUs across an array of LEDs so you can see which
Index: linux-5.4.5-rt3/drivers/md/bcache/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/drivers/md/bcache/Kconfig
+++ linux-5.4.5-rt3/drivers/md/bcache/Kconfig
@@ -2,6 +2,7 @@
 
 config BCACHE
 	tristate "Block device as cache"
+	depends on !PREEMPT_RT
 	select CRC64
 	help
 	Allows a block device to be used as cache for other devices; uses
Index: linux-5.4.5-rt3/drivers/md/raid5.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/md/raid5.c
+++ linux-5.4.5-rt3/drivers/md/raid5.c
@@ -2058,8 +2058,9 @@ static void raid_run_ops(struct stripe_h
 	struct raid5_percpu *percpu;
 	unsigned long cpu;
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
 	percpu = per_cpu_ptr(conf->percpu, cpu);
+	spin_lock(&percpu->lock);
 	if (test_bit(STRIPE_OP_BIOFILL, &ops_request)) {
 		ops_run_biofill(sh);
 		overlap_clear++;
@@ -2118,7 +2119,8 @@ static void raid_run_ops(struct stripe_h
 			if (test_and_clear_bit(R5_Overlap, &dev->flags))
 				wake_up(&sh->raid_conf->wait_for_overlap);
 		}
-	put_cpu();
+	spin_unlock(&percpu->lock);
+	put_cpu_light();
 }
 
 static void free_stripe(struct kmem_cache *sc, struct stripe_head *sh)
@@ -6821,6 +6823,7 @@ static int raid456_cpu_up_prepare(unsign
 			__func__, cpu);
 		return -ENOMEM;
 	}
+	spin_lock_init(&per_cpu_ptr(conf->percpu, cpu)->lock);
 	return 0;
 }
 
Index: linux-5.4.5-rt3/drivers/md/raid5.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/md/raid5.h
+++ linux-5.4.5-rt3/drivers/md/raid5.h
@@ -634,6 +634,7 @@ struct r5conf {
 	int			recovery_disabled;
 	/* per cpu variables */
 	struct raid5_percpu {
+		spinlock_t	lock;		/* Protection for -RT */
 		struct page	*spare_page; /* Used when checking P/Q in raid6 */
 		void		*scribble;  /* space for constructing buffer
 					     * lists and performing address
Index: linux-5.4.5-rt3/drivers/media/platform/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/drivers/media/platform/Kconfig
+++ linux-5.4.5-rt3/drivers/media/platform/Kconfig
@@ -585,7 +585,7 @@ config VIDEO_MESON_G12A_AO_CEC
 
 config CEC_GPIO
 	tristate "Generic GPIO-based CEC driver"
-	depends on PREEMPT || COMPILE_TEST
+	depends on PREEMPTION || COMPILE_TEST
 	select CEC_CORE
 	select CEC_PIN
 	select GPIOLIB
Index: linux-5.4.5-rt3/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
+++ linux-5.4.5-rt3/drivers/net/wireless/intersil/orinoco/orinoco_usb.c
@@ -693,8 +693,8 @@ static void ezusb_req_ctx_wait(struct ez
 			while (!ctx->done.done && msecs--)
 				udelay(1000);
 		} else {
-			wait_event_interruptible(ctx->done.wait,
-						 ctx->done.done);
+			swait_event_interruptible_exclusive(ctx->done.wait,
+							    ctx->done.done);
 		}
 		break;
 	default:
Index: linux-5.4.5-rt3/drivers/of/base.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/of/base.c
+++ linux-5.4.5-rt3/drivers/of/base.c
@@ -123,115 +123,38 @@ int __weak of_node_to_nid(struct device_
 }
 #endif
 
-/*
- * Assumptions behind phandle_cache implementation:
- *   - phandle property values are in a contiguous range of 1..n
- *
- * If the assumptions do not hold, then
- *   - the phandle lookup overhead reduction provided by the cache
- *     will likely be less
- */
+#define OF_PHANDLE_CACHE_BITS	7
+#define OF_PHANDLE_CACHE_SZ	BIT(OF_PHANDLE_CACHE_BITS)
 
-static struct device_node **phandle_cache;
-static u32 phandle_cache_mask;
+static struct device_node *phandle_cache[OF_PHANDLE_CACHE_SZ];
 
-/*
- * Caller must hold devtree_lock.
- */
-static void __of_free_phandle_cache(void)
+static u32 of_phandle_cache_hash(phandle handle)
 {
-	u32 cache_entries = phandle_cache_mask + 1;
-	u32 k;
-
-	if (!phandle_cache)
-		return;
-
-	for (k = 0; k < cache_entries; k++)
-		of_node_put(phandle_cache[k]);
-
-	kfree(phandle_cache);
-	phandle_cache = NULL;
+	return hash_32(handle, OF_PHANDLE_CACHE_BITS);
 }
 
-int of_free_phandle_cache(void)
-{
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&devtree_lock, flags);
-
-	__of_free_phandle_cache();
-
-	raw_spin_unlock_irqrestore(&devtree_lock, flags);
-
-	return 0;
-}
-#if !defined(CONFIG_MODULES)
-late_initcall_sync(of_free_phandle_cache);
-#endif
-
 /*
  * Caller must hold devtree_lock.
  */
-void __of_free_phandle_cache_entry(phandle handle)
+void __of_phandle_cache_inv_entry(phandle handle)
 {
-	phandle masked_handle;
+	u32 handle_hash;
 	struct device_node *np;
 
 	if (!handle)
 		return;
 
-	masked_handle = handle & phandle_cache_mask;
-
-	if (phandle_cache) {
-		np = phandle_cache[masked_handle];
-		if (np && handle == np->phandle) {
-			of_node_put(np);
-			phandle_cache[masked_handle] = NULL;
-		}
-	}
-}
-
-void of_populate_phandle_cache(void)
-{
-	unsigned long flags;
-	u32 cache_entries;
-	struct device_node *np;
-	u32 phandles = 0;
-
-	raw_spin_lock_irqsave(&devtree_lock, flags);
-
-	__of_free_phandle_cache();
+	handle_hash = of_phandle_cache_hash(handle);
 
-	for_each_of_allnodes(np)
-		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL)
-			phandles++;
-
-	if (!phandles)
-		goto out;
-
-	cache_entries = roundup_pow_of_two(phandles);
-	phandle_cache_mask = cache_entries - 1;
-
-	phandle_cache = kcalloc(cache_entries, sizeof(*phandle_cache),
-				GFP_ATOMIC);
-	if (!phandle_cache)
-		goto out;
-
-	for_each_of_allnodes(np)
-		if (np->phandle && np->phandle != OF_PHANDLE_ILLEGAL) {
-			of_node_get(np);
-			phandle_cache[np->phandle & phandle_cache_mask] = np;
-		}
-
-out:
-	raw_spin_unlock_irqrestore(&devtree_lock, flags);
+	np = phandle_cache[handle_hash];
+	if (np && handle == np->phandle)
+		phandle_cache[handle_hash] = NULL;
 }
 
 void __init of_core_init(void)
 {
 	struct device_node *np;
 
-	of_populate_phandle_cache();
 
 	/* Create the kset, and register existing nodes */
 	mutex_lock(&of_mutex);
@@ -241,8 +164,11 @@ void __init of_core_init(void)
 		pr_err("failed to register existing nodes\n");
 		return;
 	}
-	for_each_of_allnodes(np)
+	for_each_of_allnodes(np) {
 		__of_attach_node_sysfs(np);
+		if (np->phandle && !phandle_cache[of_phandle_cache_hash(np->phandle)])
+			phandle_cache[of_phandle_cache_hash(np->phandle)] = np;
+	}
 	mutex_unlock(&of_mutex);
 
 	/* Symlink in /proc as required by userspace ABI */
@@ -1223,36 +1149,29 @@ struct device_node *of_find_node_by_phan
 {
 	struct device_node *np = NULL;
 	unsigned long flags;
-	phandle masked_handle;
+	u32 handle_hash;
 
 	if (!handle)
 		return NULL;
 
-	raw_spin_lock_irqsave(&devtree_lock, flags);
+	handle_hash = of_phandle_cache_hash(handle);
 
-	masked_handle = handle & phandle_cache_mask;
+	raw_spin_lock_irqsave(&devtree_lock, flags);
 
-	if (phandle_cache) {
-		if (phandle_cache[masked_handle] &&
-		    handle == phandle_cache[masked_handle]->phandle)
-			np = phandle_cache[masked_handle];
-		if (np && of_node_check_flag(np, OF_DETACHED)) {
-			WARN_ON(1); /* did not uncache np on node removal */
-			of_node_put(np);
-			phandle_cache[masked_handle] = NULL;
-			np = NULL;
-		}
+	if (phandle_cache[handle_hash] &&
+	    handle == phandle_cache[handle_hash]->phandle)
+		np = phandle_cache[handle_hash];
+	if (np && of_node_check_flag(np, OF_DETACHED)) {
+		WARN_ON(1); /* did not uncache np on node removal */
+		phandle_cache[handle_hash] = NULL;
+		np = NULL;
 	}
 
 	if (!np) {
 		for_each_of_allnodes(np)
 			if (np->phandle == handle &&
 			    !of_node_check_flag(np, OF_DETACHED)) {
-				if (phandle_cache) {
-					/* will put when removed from cache */
-					of_node_get(np);
-					phandle_cache[masked_handle] = np;
-				}
+				phandle_cache[handle_hash] = np;
 				break;
 			}
 	}
Index: linux-5.4.5-rt3/drivers/of/dynamic.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/of/dynamic.c
+++ linux-5.4.5-rt3/drivers/of/dynamic.c
@@ -276,7 +276,7 @@ void __of_detach_node(struct device_node
 	of_node_set_flag(np, OF_DETACHED);
 
 	/* race with of_find_node_by_phandle() prevented by devtree_lock */
-	__of_free_phandle_cache_entry(np->phandle);
+	__of_phandle_cache_inv_entry(np->phandle);
 }
 
 /**
Index: linux-5.4.5-rt3/drivers/of/of_private.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/of/of_private.h
+++ linux-5.4.5-rt3/drivers/of/of_private.h
@@ -85,14 +85,12 @@ int of_resolve_phandles(struct device_no
 #endif
 
 #if defined(CONFIG_OF_DYNAMIC)
-void __of_free_phandle_cache_entry(phandle handle);
+void __of_phandle_cache_inv_entry(phandle handle);
 #endif
 
 #if defined(CONFIG_OF_OVERLAY)
 void of_overlay_mutex_lock(void);
 void of_overlay_mutex_unlock(void);
-int of_free_phandle_cache(void);
-void of_populate_phandle_cache(void);
 #else
 static inline void of_overlay_mutex_lock(void) {};
 static inline void of_overlay_mutex_unlock(void) {};
Index: linux-5.4.5-rt3/drivers/of/overlay.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/of/overlay.c
+++ linux-5.4.5-rt3/drivers/of/overlay.c
@@ -974,8 +974,6 @@ static int of_overlay_apply(const void *
 		goto err_free_overlay_changeset;
 	}
 
-	of_populate_phandle_cache();
-
 	ret = __of_changeset_apply_notify(&ovcs->cset);
 	if (ret)
 		pr_err("overlay apply changeset entry notify error %d\n", ret);
@@ -1218,17 +1216,9 @@ int of_overlay_remove(int *ovcs_id)
 
 	list_del(&ovcs->ovcs_list);
 
-	/*
-	 * Disable phandle cache.  Avoids race condition that would arise
-	 * from removing cache entry when the associated node is deleted.
-	 */
-	of_free_phandle_cache();
-
 	ret_apply = 0;
 	ret = __of_changeset_revert_entries(&ovcs->cset, &ret_apply);
 
-	of_populate_phandle_cache();
-
 	if (ret) {
 		if (ret_apply)
 			devicetree_state_flags |= DTSF_REVERT_FAIL;
Index: linux-5.4.5-rt3/drivers/pci/switch/switchtec.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/pci/switch/switchtec.c
+++ linux-5.4.5-rt3/drivers/pci/switch/switchtec.c
@@ -52,10 +52,11 @@ struct switchtec_user {
 
 	enum mrpc_state state;
 
-	struct completion comp;
+	wait_queue_head_t cmd_comp;
 	struct kref kref;
 	struct list_head list;
 
+	bool cmd_done;
 	u32 cmd;
 	u32 status;
 	u32 return_code;
@@ -77,7 +78,7 @@ static struct switchtec_user *stuser_cre
 	stuser->stdev = stdev;
 	kref_init(&stuser->kref);
 	INIT_LIST_HEAD(&stuser->list);
-	init_completion(&stuser->comp);
+	init_waitqueue_head(&stuser->cmd_comp);
 	stuser->event_cnt = atomic_read(&stdev->event_cnt);
 
 	dev_dbg(&stdev->dev, "%s: %p\n", __func__, stuser);
@@ -175,7 +176,7 @@ static int mrpc_queue_cmd(struct switcht
 	kref_get(&stuser->kref);
 	stuser->read_len = sizeof(stuser->data);
 	stuser_set_state(stuser, MRPC_QUEUED);
-	init_completion(&stuser->comp);
+	stuser->cmd_done = false;
 	list_add_tail(&stuser->list, &stdev->mrpc_queue);
 
 	mrpc_cmd_submit(stdev);
@@ -222,7 +223,8 @@ static void mrpc_complete_cmd(struct swi
 		memcpy_fromio(stuser->data, &stdev->mmio_mrpc->output_data,
 			      stuser->read_len);
 out:
-	complete_all(&stuser->comp);
+	stuser->cmd_done = true;
+	wake_up_interruptible(&stuser->cmd_comp);
 	list_del_init(&stuser->list);
 	stuser_put(stuser);
 	stdev->mrpc_busy = 0;
@@ -494,10 +496,11 @@ static ssize_t switchtec_dev_read(struct
 	mutex_unlock(&stdev->mrpc_mutex);
 
 	if (filp->f_flags & O_NONBLOCK) {
-		if (!try_wait_for_completion(&stuser->comp))
+		if (!READ_ONCE(stuser->cmd_done))
 			return -EAGAIN;
 	} else {
-		rc = wait_for_completion_interruptible(&stuser->comp);
+		rc = wait_event_interruptible(stuser->cmd_comp,
+					      stuser->cmd_done);
 		if (rc < 0)
 			return rc;
 	}
@@ -545,7 +548,7 @@ static __poll_t switchtec_dev_poll(struc
 	struct switchtec_dev *stdev = stuser->stdev;
 	__poll_t ret = 0;
 
-	poll_wait(filp, &stuser->comp.wait, wait);
+	poll_wait(filp, &stuser->cmd_comp, wait);
 	poll_wait(filp, &stdev->event_wq, wait);
 
 	if (lock_mutex_and_test_alive(stdev))
@@ -553,7 +556,7 @@ static __poll_t switchtec_dev_poll(struc
 
 	mutex_unlock(&stdev->mrpc_mutex);
 
-	if (try_wait_for_completion(&stuser->comp))
+	if (READ_ONCE(stuser->cmd_done))
 		ret |= EPOLLIN | EPOLLRDNORM;
 
 	if (stuser->event_cnt != atomic_read(&stdev->event_cnt))
@@ -1106,7 +1109,8 @@ static void stdev_kill(struct switchtec_
 
 	/* Wake up and kill any users waiting on an MRPC request */
 	list_for_each_entry_safe(stuser, tmpuser, &stdev->mrpc_queue, list) {
-		complete_all(&stuser->comp);
+		stuser->cmd_done = true;
+		wake_up_interruptible(&stuser->cmd_comp);
 		list_del_init(&stuser->list);
 		stuser_put(stuser);
 	}
Index: linux-5.4.5-rt3/drivers/scsi/fcoe/fcoe.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/scsi/fcoe/fcoe.c
+++ linux-5.4.5-rt3/drivers/scsi/fcoe/fcoe.c
@@ -1452,11 +1452,11 @@ err2:
 static int fcoe_alloc_paged_crc_eof(struct sk_buff *skb, int tlen)
 {
 	struct fcoe_percpu_s *fps;
-	int rc;
+	int rc, cpu = get_cpu_light();
 
-	fps = &get_cpu_var(fcoe_percpu);
+	fps = &per_cpu(fcoe_percpu, cpu);
 	rc = fcoe_get_paged_crc_eof(skb, tlen, fps);
-	put_cpu_var(fcoe_percpu);
+	put_cpu_light();
 
 	return rc;
 }
@@ -1641,11 +1641,11 @@ static inline int fcoe_filter_frames(str
 		return 0;
 	}
 
-	stats = per_cpu_ptr(lport->stats, get_cpu());
+	stats = per_cpu_ptr(lport->stats, get_cpu_light());
 	stats->InvalidCRCCount++;
 	if (stats->InvalidCRCCount < 5)
 		printk(KERN_WARNING "fcoe: dropping frame with CRC error\n");
-	put_cpu();
+	put_cpu_light();
 	return -EINVAL;
 }
 
@@ -1686,7 +1686,7 @@ static void fcoe_recv_frame(struct sk_bu
 	 */
 	hp = (struct fcoe_hdr *) skb_network_header(skb);
 
-	stats = per_cpu_ptr(lport->stats, get_cpu());
+	stats = per_cpu_ptr(lport->stats, get_cpu_light());
 	if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) {
 		if (stats->ErrorFrames < 5)
 			printk(KERN_WARNING "fcoe: FCoE version "
@@ -1718,13 +1718,13 @@ static void fcoe_recv_frame(struct sk_bu
 		goto drop;
 
 	if (!fcoe_filter_frames(lport, fp)) {
-		put_cpu();
+		put_cpu_light();
 		fc_exch_recv(lport, fp);
 		return;
 	}
 drop:
 	stats->ErrorFrames++;
-	put_cpu();
+	put_cpu_light();
 	kfree_skb(skb);
 }
 
Index: linux-5.4.5-rt3/drivers/scsi/fcoe/fcoe_ctlr.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/scsi/fcoe/fcoe_ctlr.c
+++ linux-5.4.5-rt3/drivers/scsi/fcoe/fcoe_ctlr.c
@@ -826,7 +826,7 @@ static unsigned long fcoe_ctlr_age_fcfs(
 
 	INIT_LIST_HEAD(&del_list);
 
-	stats = per_cpu_ptr(fip->lp->stats, get_cpu());
+	stats = per_cpu_ptr(fip->lp->stats, get_cpu_light());
 
 	list_for_each_entry_safe(fcf, next, &fip->fcfs, list) {
 		deadline = fcf->time + fcf->fka_period + fcf->fka_period / 2;
@@ -862,7 +862,7 @@ static unsigned long fcoe_ctlr_age_fcfs(
 				sel_time = fcf->time;
 		}
 	}
-	put_cpu();
+	put_cpu_light();
 
 	list_for_each_entry_safe(fcf, next, &del_list, list) {
 		/* Removes fcf from current list */
Index: linux-5.4.5-rt3/drivers/scsi/libfc/fc_exch.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/scsi/libfc/fc_exch.c
+++ linux-5.4.5-rt3/drivers/scsi/libfc/fc_exch.c
@@ -821,10 +821,10 @@ static struct fc_exch *fc_exch_em_alloc(
 	}
 	memset(ep, 0, sizeof(*ep));
 
-	cpu = get_cpu();
+	cpu = get_cpu_light();
 	pool = per_cpu_ptr(mp->pool, cpu);
 	spin_lock_bh(&pool->lock);
-	put_cpu();
+	put_cpu_light();
 
 	/* peek cache of free slot */
 	if (pool->left != FC_XID_UNKNOWN) {
Index: linux-5.4.5-rt3/drivers/thermal/intel/x86_pkg_temp_thermal.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/thermal/intel/x86_pkg_temp_thermal.c
+++ linux-5.4.5-rt3/drivers/thermal/intel/x86_pkg_temp_thermal.c
@@ -63,7 +63,7 @@ static int max_id __read_mostly;
 /* Array of zone pointers */
 static struct zone_device **zones;
 /* Serializes interrupt notification, work and hotplug */
-static DEFINE_SPINLOCK(pkg_temp_lock);
+static DEFINE_RAW_SPINLOCK(pkg_temp_lock);
 /* Protects zone operation in the work function against hotplug removal */
 static DEFINE_MUTEX(thermal_zone_mutex);
 
@@ -266,12 +266,12 @@ static void pkg_temp_thermal_threshold_w
 	u64 msr_val, wr_val;
 
 	mutex_lock(&thermal_zone_mutex);
-	spin_lock_irq(&pkg_temp_lock);
+	raw_spin_lock_irq(&pkg_temp_lock);
 	++pkg_work_cnt;
 
 	zonedev = pkg_temp_thermal_get_dev(cpu);
 	if (!zonedev) {
-		spin_unlock_irq(&pkg_temp_lock);
+		raw_spin_unlock_irq(&pkg_temp_lock);
 		mutex_unlock(&thermal_zone_mutex);
 		return;
 	}
@@ -285,7 +285,7 @@ static void pkg_temp_thermal_threshold_w
 	}
 
 	enable_pkg_thres_interrupt();
-	spin_unlock_irq(&pkg_temp_lock);
+	raw_spin_unlock_irq(&pkg_temp_lock);
 
 	/*
 	 * If tzone is not NULL, then thermal_zone_mutex will prevent the
@@ -310,7 +310,7 @@ static int pkg_thermal_notify(u64 msr_va
 	struct zone_device *zonedev;
 	unsigned long flags;
 
-	spin_lock_irqsave(&pkg_temp_lock, flags);
+	raw_spin_lock_irqsave(&pkg_temp_lock, flags);
 	++pkg_interrupt_cnt;
 
 	disable_pkg_thres_interrupt();
@@ -322,7 +322,7 @@ static int pkg_thermal_notify(u64 msr_va
 		pkg_thermal_schedule_work(zonedev->cpu, &zonedev->work);
 	}
 
-	spin_unlock_irqrestore(&pkg_temp_lock, flags);
+	raw_spin_unlock_irqrestore(&pkg_temp_lock, flags);
 	return 0;
 }
 
@@ -368,9 +368,9 @@ static int pkg_temp_thermal_device_add(u
 	      zonedev->msr_pkg_therm_high);
 
 	cpumask_set_cpu(cpu, &zonedev->cpumask);
-	spin_lock_irq(&pkg_temp_lock);
+	raw_spin_lock_irq(&pkg_temp_lock);
 	zones[id] = zonedev;
-	spin_unlock_irq(&pkg_temp_lock);
+	raw_spin_unlock_irq(&pkg_temp_lock);
 	return 0;
 }
 
@@ -407,7 +407,7 @@ static int pkg_thermal_cpu_offline(unsig
 	}
 
 	/* Protect against work and interrupts */
-	spin_lock_irq(&pkg_temp_lock);
+	raw_spin_lock_irq(&pkg_temp_lock);
 
 	/*
 	 * Check whether this cpu was the current target and store the new
@@ -439,9 +439,9 @@ static int pkg_thermal_cpu_offline(unsig
 		 * To cancel the work we need to drop the lock, otherwise
 		 * we might deadlock if the work needs to be flushed.
 		 */
-		spin_unlock_irq(&pkg_temp_lock);
+		raw_spin_unlock_irq(&pkg_temp_lock);
 		cancel_delayed_work_sync(&zonedev->work);
-		spin_lock_irq(&pkg_temp_lock);
+		raw_spin_lock_irq(&pkg_temp_lock);
 		/*
 		 * If this is not the last cpu in the package and the work
 		 * did not run after we dropped the lock above, then we
@@ -452,7 +452,7 @@ static int pkg_thermal_cpu_offline(unsig
 			pkg_thermal_schedule_work(target, &zonedev->work);
 	}
 
-	spin_unlock_irq(&pkg_temp_lock);
+	raw_spin_unlock_irq(&pkg_temp_lock);
 
 	/* Final cleanup if this is the last cpu */
 	if (lastcpu)
Index: linux-5.4.5-rt3/drivers/tty/serial/8250/8250.h
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/8250/8250.h
+++ linux-5.4.5-rt3/drivers/tty/serial/8250/8250.h
@@ -130,12 +130,55 @@ static inline void serial_dl_write(struc
 	up->dl_write(up, value);
 }
 
+static inline void serial8250_set_IER(struct uart_8250_port *up,
+				      unsigned char ier)
+{
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	bool is_console;
+
+	is_console = uart_console(port);
+
+	if (is_console)
+		console_atomic_lock(&flags);
+
+	serial_out(up, UART_IER, ier);
+
+	if (is_console)
+		console_atomic_unlock(flags);
+}
+
+static inline unsigned char serial8250_clear_IER(struct uart_8250_port *up)
+{
+	struct uart_port *port = &up->port;
+	unsigned int clearval = 0;
+	unsigned int prior;
+	unsigned int flags;
+	bool is_console;
+
+	is_console = uart_console(port);
+
+	if (up->capabilities & UART_CAP_UUE)
+		clearval = UART_IER_UUE;
+
+	if (is_console)
+		console_atomic_lock(&flags);
+
+	prior = serial_port_in(port, UART_IER);
+	serial_port_out(port, UART_IER, clearval);
+
+	if (is_console)
+		console_atomic_unlock(flags);
+
+	return prior;
+}
+
 static inline bool serial8250_set_THRI(struct uart_8250_port *up)
 {
 	if (up->ier & UART_IER_THRI)
 		return false;
 	up->ier |= UART_IER_THRI;
-	serial_out(up, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 	return true;
 }
 
@@ -144,7 +187,7 @@ static inline bool serial8250_clear_THRI
 	if (!(up->ier & UART_IER_THRI))
 		return false;
 	up->ier &= ~UART_IER_THRI;
-	serial_out(up, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 	return true;
 }
 
Index: linux-5.4.5-rt3/drivers/tty/serial/8250/8250_core.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/8250/8250_core.c
+++ linux-5.4.5-rt3/drivers/tty/serial/8250/8250_core.c
@@ -55,7 +55,16 @@ static struct uart_driver serial8250_reg
 
 static unsigned int skip_txen_test; /* force skip of txen test at init time */
 
-#define PASS_LIMIT	512
+/*
+ * On -rt we can have a more delays, and legitimately
+ * so - so don't drop work spuriously and spam the
+ * syslog:
+ */
+#ifdef CONFIG_PREEMPT_RT
+# define PASS_LIMIT	1000000
+#else
+# define PASS_LIMIT	512
+#endif
 
 #include <asm/serial.h>
 /*
@@ -275,10 +284,8 @@ static void serial8250_backup_timeout(st
 	 * Must disable interrupts or else we risk racing with the interrupt
 	 * based handler.
 	 */
-	if (up->port.irq) {
-		ier = serial_in(up, UART_IER);
-		serial_out(up, UART_IER, 0);
-	}
+	if (up->port.irq)
+		ier = serial8250_clear_IER(up);
 
 	iir = serial_in(up, UART_IIR);
 
@@ -301,7 +308,7 @@ static void serial8250_backup_timeout(st
 		serial8250_tx_chars(up);
 
 	if (up->port.irq)
-		serial_out(up, UART_IER, ier);
+		serial8250_set_IER(up, ier);
 
 	spin_unlock_irqrestore(&up->port.lock, flags);
 
@@ -579,6 +586,14 @@ serial8250_register_ports(struct uart_dr
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
+static void univ8250_console_write_atomic(struct console *co, const char *s,
+					  unsigned int count)
+{
+	struct uart_8250_port *up = &serial8250_ports[co->index];
+
+	serial8250_console_write_atomic(up, s, count);
+}
+
 static void univ8250_console_write(struct console *co, const char *s,
 				   unsigned int count)
 {
@@ -664,6 +679,7 @@ static int univ8250_console_match(struct
 
 static struct console univ8250_console = {
 	.name		= "ttyS",
+	.write_atomic	= univ8250_console_write_atomic,
 	.write		= univ8250_console_write,
 	.device		= uart_console_device,
 	.setup		= univ8250_console_setup,
Index: linux-5.4.5-rt3/drivers/tty/serial/8250/8250_fsl.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/8250/8250_fsl.c
+++ linux-5.4.5-rt3/drivers/tty/serial/8250/8250_fsl.c
@@ -57,9 +57,18 @@ int fsl8250_handle_irq(struct uart_port
 
 	/* Stop processing interrupts on input overrun */
 	if ((orig_lsr & UART_LSR_OE) && (up->overrun_backoff_time_ms > 0)) {
+		unsigned int ca_flags;
 		unsigned long delay;
+		bool is_console;
 
+		is_console = uart_console(port);
+
+		if (is_console)
+			console_atomic_lock(&ca_flags);
 		up->ier = port->serial_in(port, UART_IER);
+		if (is_console)
+			console_atomic_unlock(ca_flags);
+
 		if (up->ier & (UART_IER_RLSI | UART_IER_RDI)) {
 			port->ops->stop_rx(port);
 		} else {
Index: linux-5.4.5-rt3/drivers/tty/serial/8250/8250_ingenic.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/8250/8250_ingenic.c
+++ linux-5.4.5-rt3/drivers/tty/serial/8250/8250_ingenic.c
@@ -146,6 +146,8 @@ OF_EARLYCON_DECLARE(x1000_uart, "ingenic
 
 static void ingenic_uart_serial_out(struct uart_port *p, int offset, int value)
 {
+	unsigned int flags;
+	bool is_console;
 	int ier;
 
 	switch (offset) {
@@ -167,7 +169,12 @@ static void ingenic_uart_serial_out(stru
 		 * If we have enabled modem status IRQs we should enable
 		 * modem mode.
 		 */
+		is_console = uart_console(p);
+		if (is_console)
+			console_atomic_lock(&flags);
 		ier = p->serial_in(p, UART_IER);
+		if (is_console)
+			console_atomic_unlock(flags);
 
 		if (ier & UART_IER_MSI)
 			value |= UART_MCR_MDCE | UART_MCR_FCM;
Index: linux-5.4.5-rt3/drivers/tty/serial/8250/8250_mtk.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/8250/8250_mtk.c
+++ linux-5.4.5-rt3/drivers/tty/serial/8250/8250_mtk.c
@@ -212,12 +212,37 @@ static void mtk8250_shutdown(struct uart
 
 static void mtk8250_disable_intrs(struct uart_8250_port *up, int mask)
 {
-	serial_out(up, UART_IER, serial_in(up, UART_IER) & (~mask));
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	unsigned int ier;
+	bool is_console;
+
+	is_console = uart_console(port);
+
+	if (is_console)
+		console_atomic_lock(&flags);
+
+	ier = serial_in(up, UART_IER);
+	serial_out(up, UART_IER, ier & (~mask));
+
+	if (is_console)
+		console_atomic_unlock(flags);
 }
 
 static void mtk8250_enable_intrs(struct uart_8250_port *up, int mask)
 {
-	serial_out(up, UART_IER, serial_in(up, UART_IER) | mask);
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	unsigned int ier;
+
+	if (uart_console(port))
+		console_atomic_lock(&flags);
+
+	ier = serial_in(up, UART_IER);
+	serial_out(up, UART_IER, ier | mask);
+
+	if (uart_console(port))
+		console_atomic_unlock(flags);
 }
 
 static void mtk8250_set_flow_ctrl(struct uart_8250_port *up, int mode)
Index: linux-5.4.5-rt3/drivers/tty/serial/8250/8250_port.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/8250/8250_port.c
+++ linux-5.4.5-rt3/drivers/tty/serial/8250/8250_port.c
@@ -721,7 +721,7 @@ static void serial8250_set_sleep(struct
 			serial_out(p, UART_EFR, UART_EFR_ECB);
 			serial_out(p, UART_LCR, 0);
 		}
-		serial_out(p, UART_IER, sleep ? UART_IERX_SLEEP : 0);
+		serial8250_set_IER(p, sleep ? UART_IERX_SLEEP : 0);
 		if (p->capabilities & UART_CAP_EFR) {
 			serial_out(p, UART_LCR, UART_LCR_CONF_MODE_B);
 			serial_out(p, UART_EFR, efr);
@@ -1390,7 +1390,7 @@ static void serial8250_stop_rx(struct ua
 
 	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
 	up->port.read_status_mask &= ~UART_LSR_DR;
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 
 	serial8250_rpm_put(up);
 }
@@ -1408,7 +1408,7 @@ static void __do_stop_tx_rs485(struct ua
 		serial8250_clear_and_reinit_fifos(p);
 
 		p->ier |= UART_IER_RLSI | UART_IER_RDI;
-		serial_port_out(&p->port, UART_IER, p->ier);
+		serial8250_set_IER(p, p->ier);
 	}
 }
 static enum hrtimer_restart serial8250_em485_handle_stop_tx(struct hrtimer *t)
@@ -1616,7 +1616,7 @@ static void serial8250_disable_ms(struct
 	mctrl_gpio_disable_ms(up->gpios);
 
 	up->ier &= ~UART_IER_MSI;
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 }
 
 static void serial8250_enable_ms(struct uart_port *port)
@@ -1632,7 +1632,7 @@ static void serial8250_enable_ms(struct
 	up->ier |= UART_IER_MSI;
 
 	serial8250_rpm_get(up);
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 	serial8250_rpm_put(up);
 }
 
@@ -2026,14 +2026,7 @@ static void serial8250_put_poll_char(str
 	struct uart_8250_port *up = up_to_u8250p(port);
 
 	serial8250_rpm_get(up);
-	/*
-	 *	First save the IER then disable the interrupts
-	 */
-	ier = serial_port_in(port, UART_IER);
-	if (up->capabilities & UART_CAP_UUE)
-		serial_port_out(port, UART_IER, UART_IER_UUE);
-	else
-		serial_port_out(port, UART_IER, 0);
+	ier = serial8250_clear_IER(up);
 
 	wait_for_xmitr(up, BOTH_EMPTY);
 	/*
@@ -2046,7 +2039,7 @@ static void serial8250_put_poll_char(str
 	 *	and restore the IER
 	 */
 	wait_for_xmitr(up, BOTH_EMPTY);
-	serial_port_out(port, UART_IER, ier);
+	serial8250_set_IER(up, ier);
 	serial8250_rpm_put(up);
 }
 
@@ -2354,7 +2347,7 @@ void serial8250_do_shutdown(struct uart_
 	 */
 	spin_lock_irqsave(&port->lock, flags);
 	up->ier = 0;
-	serial_port_out(port, UART_IER, 0);
+	serial8250_set_IER(up, 0);
 	spin_unlock_irqrestore(&port->lock, flags);
 
 	synchronize_irq(port->irq);
@@ -2639,7 +2632,7 @@ serial8250_do_set_termios(struct uart_po
 	if (up->capabilities & UART_CAP_RTOIE)
 		up->ier |= UART_IER_RTOIE;
 
-	serial_port_out(port, UART_IER, up->ier);
+	serial8250_set_IER(up, up->ier);
 
 	if (up->capabilities & UART_CAP_EFR) {
 		unsigned char efr = 0;
@@ -3103,7 +3096,7 @@ EXPORT_SYMBOL_GPL(serial8250_set_default
 
 #ifdef CONFIG_SERIAL_8250_CONSOLE
 
-static void serial8250_console_putchar(struct uart_port *port, int ch)
+static void serial8250_console_putchar_locked(struct uart_port *port, int ch)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
@@ -3111,6 +3104,18 @@ static void serial8250_console_putchar(s
 	serial_port_out(port, UART_TX, ch);
 }
 
+static void serial8250_console_putchar(struct uart_port *port, int ch)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	unsigned int flags;
+
+	wait_for_xmitr(up, UART_LSR_THRE);
+
+	console_atomic_lock(&flags);
+	serial8250_console_putchar_locked(port, ch);
+	console_atomic_unlock(flags);
+}
+
 /*
  *	Restore serial console when h/w power-off detected
  */
@@ -3132,6 +3137,32 @@ static void serial8250_console_restore(s
 	serial8250_out_MCR(up, UART_MCR_DTR | UART_MCR_RTS);
 }
 
+void serial8250_console_write_atomic(struct uart_8250_port *up,
+				     const char *s, unsigned int count)
+{
+	struct uart_port *port = &up->port;
+	unsigned int flags;
+	unsigned int ier;
+
+	console_atomic_lock(&flags);
+
+	touch_nmi_watchdog();
+
+	ier = serial8250_clear_IER(up);
+
+	if (atomic_fetch_inc(&up->console_printing)) {
+		uart_console_write(port, "\n", 1,
+				   serial8250_console_putchar_locked);
+	}
+	uart_console_write(port, s, count, serial8250_console_putchar_locked);
+	atomic_dec(&up->console_printing);
+
+	wait_for_xmitr(up, BOTH_EMPTY);
+	serial8250_set_IER(up, ier);
+
+	console_atomic_unlock(flags);
+}
+
 /*
  *	Print a string to the serial port trying not to disturb
  *	any possible real use of the port...
@@ -3144,26 +3175,13 @@ void serial8250_console_write(struct uar
 	struct uart_port *port = &up->port;
 	unsigned long flags;
 	unsigned int ier;
-	int locked = 1;
 
 	touch_nmi_watchdog();
 
 	serial8250_rpm_get(up);
+	spin_lock_irqsave(&port->lock, flags);
 
-	if (oops_in_progress)
-		locked = spin_trylock_irqsave(&port->lock, flags);
-	else
-		spin_lock_irqsave(&port->lock, flags);
-
-	/*
-	 *	First save the IER then disable the interrupts
-	 */
-	ier = serial_port_in(port, UART_IER);
-
-	if (up->capabilities & UART_CAP_UUE)
-		serial_port_out(port, UART_IER, UART_IER_UUE);
-	else
-		serial_port_out(port, UART_IER, 0);
+	ier = serial8250_clear_IER(up);
 
 	/* check scratch reg to see if port powered off during system sleep */
 	if (up->canary && (up->canary != serial_port_in(port, UART_SCR))) {
@@ -3171,14 +3189,16 @@ void serial8250_console_write(struct uar
 		up->canary = 0;
 	}
 
+	atomic_inc(&up->console_printing);
 	uart_console_write(port, s, count, serial8250_console_putchar);
+	atomic_dec(&up->console_printing);
 
 	/*
 	 *	Finally, wait for transmitter to become empty
 	 *	and restore the IER
 	 */
 	wait_for_xmitr(up, BOTH_EMPTY);
-	serial_port_out(port, UART_IER, ier);
+	serial8250_set_IER(up, ier);
 
 	/*
 	 *	The receive handling will happen properly because the
@@ -3190,8 +3210,7 @@ void serial8250_console_write(struct uar
 	if (up->msr_saved_flags)
 		serial8250_modem_status(up);
 
-	if (locked)
-		spin_unlock_irqrestore(&port->lock, flags);
+	spin_unlock_irqrestore(&port->lock, flags);
 	serial8250_rpm_put(up);
 }
 
@@ -3212,6 +3231,7 @@ static unsigned int probe_baud(struct ua
 
 int serial8250_console_setup(struct uart_port *port, char *options, bool probe)
 {
+	struct uart_8250_port *up = up_to_u8250p(port);
 	int baud = 9600;
 	int bits = 8;
 	int parity = 'n';
@@ -3220,6 +3240,8 @@ int serial8250_console_setup(struct uart
 	if (!port->iobase && !port->membase)
 		return -ENODEV;
 
+	atomic_set(&up->console_printing, 0);
+
 	if (options)
 		uart_parse_options(options, &baud, &parity, &bits, &flow);
 	else if (probe)
Index: linux-5.4.5-rt3/drivers/tty/serial/amba-pl011.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/amba-pl011.c
+++ linux-5.4.5-rt3/drivers/tty/serial/amba-pl011.c
@@ -2209,18 +2209,24 @@ pl011_console_write(struct console *co,
 {
 	struct uart_amba_port *uap = amba_ports[co->index];
 	unsigned int old_cr = 0, new_cr;
-	unsigned long flags;
+	unsigned long flags = 0;
 	int locked = 1;
 
 	clk_enable(uap->clk);
 
-	local_irq_save(flags);
+	/*
+	 * local_irq_save(flags);
+	 *
+	 * This local_irq_save() is nonsense. If we come in via sysrq
+	 * handling then interrupts are already disabled. Aside of
+	 * that the port.sysrq check is racy on SMP regardless.
+	*/
 	if (uap->port.sysrq)
 		locked = 0;
 	else if (oops_in_progress)
-		locked = spin_trylock(&uap->port.lock);
+		locked = spin_trylock_irqsave(&uap->port.lock, flags);
 	else
-		spin_lock(&uap->port.lock);
+		spin_lock_irqsave(&uap->port.lock, flags);
 
 	/*
 	 *	First save the CR then disable the interrupts
@@ -2246,8 +2252,7 @@ pl011_console_write(struct console *co,
 		pl011_write(old_cr, uap, REG_CR);
 
 	if (locked)
-		spin_unlock(&uap->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&uap->port.lock, flags);
 
 	clk_disable(uap->clk);
 }
Index: linux-5.4.5-rt3/drivers/tty/serial/omap-serial.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/tty/serial/omap-serial.c
+++ linux-5.4.5-rt3/drivers/tty/serial/omap-serial.c
@@ -1307,13 +1307,10 @@ serial_omap_console_write(struct console
 
 	pm_runtime_get_sync(up->dev);
 
-	local_irq_save(flags);
-	if (up->port.sysrq)
-		locked = 0;
-	else if (oops_in_progress)
-		locked = spin_trylock(&up->port.lock);
+	if (up->port.sysrq || oops_in_progress)
+		locked = spin_trylock_irqsave(&up->port.lock, flags);
 	else
-		spin_lock(&up->port.lock);
+		spin_lock_irqsave(&up->port.lock, flags);
 
 	/*
 	 * First save the IER then disable the interrupts
@@ -1342,8 +1339,7 @@ serial_omap_console_write(struct console
 	pm_runtime_mark_last_busy(up->dev);
 	pm_runtime_put_autosuspend(up->dev);
 	if (locked)
-		spin_unlock(&up->port.lock);
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&up->port.lock, flags);
 }
 
 static int __init
Index: linux-5.4.5-rt3/drivers/usb/gadget/function/f_fs.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/usb/gadget/function/f_fs.c
+++ linux-5.4.5-rt3/drivers/usb/gadget/function/f_fs.c
@@ -1715,7 +1715,7 @@ static void ffs_data_put(struct ffs_data
 		pr_info("%s(): freeing\n", __func__);
 		ffs_data_clear(ffs);
 		BUG_ON(waitqueue_active(&ffs->ev.waitq) ||
-		       waitqueue_active(&ffs->ep0req_completion.wait) ||
+		       swait_active(&ffs->ep0req_completion.wait) ||
 		       waitqueue_active(&ffs->wait));
 		destroy_workqueue(ffs->io_completion_wq);
 		kfree(ffs->dev_name);
Index: linux-5.4.5-rt3/drivers/usb/gadget/legacy/inode.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/usb/gadget/legacy/inode.c
+++ linux-5.4.5-rt3/drivers/usb/gadget/legacy/inode.c
@@ -344,7 +344,7 @@ ep_io (struct ep_data *epdata, void *buf
 	spin_unlock_irq (&epdata->dev->lock);
 
 	if (likely (value == 0)) {
-		value = wait_event_interruptible (done.wait, done.done);
+		value = swait_event_interruptible_exclusive(done.wait, done.done);
 		if (value != 0) {
 			spin_lock_irq (&epdata->dev->lock);
 			if (likely (epdata->ep != NULL)) {
@@ -353,7 +353,7 @@ ep_io (struct ep_data *epdata, void *buf
 				usb_ep_dequeue (epdata->ep, epdata->req);
 				spin_unlock_irq (&epdata->dev->lock);
 
-				wait_event (done.wait, done.done);
+				swait_event_exclusive(done.wait, done.done);
 				if (epdata->status == -ECONNRESET)
 					epdata->status = -EINTR;
 			} else {
Index: linux-5.4.5-rt3/drivers/video/backlight/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/drivers/video/backlight/Kconfig
+++ linux-5.4.5-rt3/drivers/video/backlight/Kconfig
@@ -99,7 +99,7 @@ config LCD_TOSA
 
 config LCD_HP700
 	tristate "HP Jornada 700 series LCD Driver"
-	depends on SA1100_JORNADA720_SSP && !PREEMPT
+	depends on SA1100_JORNADA720_SSP && !PREEMPTION
 	default y
 	help
 	  If you have an HP Jornada 700 series handheld (710/720/728)
@@ -228,7 +228,7 @@ config BACKLIGHT_HP680
 
 config BACKLIGHT_HP700
 	tristate "HP Jornada 700 series Backlight Driver"
-	depends on SA1100_JORNADA720_SSP && !PREEMPT
+	depends on SA1100_JORNADA720_SSP && !PREEMPTION
 	default y
 	help
 	  If you have an HP Jornada 700 series,
Index: linux-5.4.5-rt3/drivers/xen/preempt.c
===================================================================
--- linux-5.4.5-rt3.orig/drivers/xen/preempt.c
+++ linux-5.4.5-rt3/drivers/xen/preempt.c
@@ -8,7 +8,7 @@
 #include <linux/sched.h>
 #include <xen/xen-ops.h>
 
-#ifndef CONFIG_PREEMPT
+#ifndef CONFIG_PREEMPTION
 
 /*
  * Some hypercalls issued by the toolstack can take many 10s of
@@ -37,4 +37,4 @@ asmlinkage __visible void xen_maybe_pree
 		__this_cpu_write(xen_in_preemptible_hcall, true);
 	}
 }
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
Index: linux-5.4.5-rt3/fs/afs/dir_silly.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/afs/dir_silly.c
+++ linux-5.4.5-rt3/fs/afs/dir_silly.c
@@ -202,7 +202,7 @@ int afs_silly_iput(struct dentry *dentry
 	struct dentry *alias;
 	int ret;
 
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	_enter("%p{%pd},%llx", dentry, dentry, vnode->fid.vnode);
 
Index: linux-5.4.5-rt3/fs/btrfs/volumes.h
===================================================================
--- linux-5.4.5-rt3.orig/fs/btrfs/volumes.h
+++ linux-5.4.5-rt3/fs/btrfs/volumes.h
@@ -179,7 +179,7 @@ btrfs_device_set_##name(struct btrfs_dev
 	write_seqcount_end(&dev->data_seqcount);			\
 	preempt_enable();						\
 }
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 #define BTRFS_DEVICE_GETSET_FUNCS(name)					\
 static inline u64							\
 btrfs_device_get_##name(const struct btrfs_device *dev)			\
Index: linux-5.4.5-rt3/fs/buffer.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/buffer.c
+++ linux-5.4.5-rt3/fs/buffer.c
@@ -275,8 +275,7 @@ static void end_buffer_async_read(struct
 	 * decide that the page is now completely done.
 	 */
 	first = page_buffers(page);
-	local_irq_save(flags);
-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
+	spin_lock_irqsave(&first->b_uptodate_lock, flags);
 	clear_buffer_async_read(bh);
 	unlock_buffer(bh);
 	tmp = bh;
@@ -289,8 +288,7 @@ static void end_buffer_async_read(struct
 		}
 		tmp = tmp->b_this_page;
 	} while (tmp != bh);
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
 
 	/*
 	 * If none of the buffers had errors and they are all
@@ -302,8 +300,7 @@ static void end_buffer_async_read(struct
 	return;
 
 still_busy:
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
 	return;
 }
 
@@ -331,8 +328,7 @@ void end_buffer_async_write(struct buffe
 	}
 
 	first = page_buffers(page);
-	local_irq_save(flags);
-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
+	spin_lock_irqsave(&first->b_uptodate_lock, flags);
 
 	clear_buffer_async_write(bh);
 	unlock_buffer(bh);
@@ -344,14 +340,12 @@ void end_buffer_async_write(struct buffe
 		}
 		tmp = tmp->b_this_page;
 	}
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
 	end_page_writeback(page);
 	return;
 
 still_busy:
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
 	return;
 }
 EXPORT_SYMBOL(end_buffer_async_write);
@@ -1393,7 +1387,7 @@ static bool has_bh_in_lru(int cpu, void
 
 void invalidate_bh_lrus(void)
 {
-	on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1, GFP_KERNEL);
+	on_each_cpu_cond(has_bh_in_lru, invalidate_bh_lru, NULL, 1);
 }
 EXPORT_SYMBOL_GPL(invalidate_bh_lrus);
 
@@ -3345,6 +3339,7 @@ struct buffer_head *alloc_buffer_head(gf
 	struct buffer_head *ret = kmem_cache_zalloc(bh_cachep, gfp_flags);
 	if (ret) {
 		INIT_LIST_HEAD(&ret->b_assoc_buffers);
+		spin_lock_init(&ret->b_uptodate_lock);
 		preempt_disable();
 		__this_cpu_inc(bh_accounting.nr);
 		recalc_bh_state();
Index: linux-5.4.5-rt3/fs/cifs/readdir.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/cifs/readdir.c
+++ linux-5.4.5-rt3/fs/cifs/readdir.c
@@ -80,7 +80,7 @@ cifs_prime_dcache(struct dentry *parent,
 	struct inode *inode;
 	struct super_block *sb = parent->d_sb;
 	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
 
Index: linux-5.4.5-rt3/fs/dcache.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/dcache.c
+++ linux-5.4.5-rt3/fs/dcache.c
@@ -2482,9 +2482,10 @@ EXPORT_SYMBOL(d_rehash);
 static inline unsigned start_dir_add(struct inode *dir)
 {
 
+	preempt_disable_rt();
 	for (;;) {
-		unsigned n = dir->i_dir_seq;
-		if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n)
+		unsigned n = dir->__i_dir_seq;
+		if (!(n & 1) && cmpxchg(&dir->__i_dir_seq, n, n + 1) == n)
 			return n;
 		cpu_relax();
 	}
@@ -2492,26 +2493,30 @@ static inline unsigned start_dir_add(str
 
 static inline void end_dir_add(struct inode *dir, unsigned n)
 {
-	smp_store_release(&dir->i_dir_seq, n + 2);
+	smp_store_release(&dir->__i_dir_seq, n + 2);
+	preempt_enable_rt();
 }
 
 static void d_wait_lookup(struct dentry *dentry)
 {
-	if (d_in_lookup(dentry)) {
-		DECLARE_WAITQUEUE(wait, current);
-		add_wait_queue(dentry->d_wait, &wait);
-		do {
-			set_current_state(TASK_UNINTERRUPTIBLE);
-			spin_unlock(&dentry->d_lock);
-			schedule();
-			spin_lock(&dentry->d_lock);
-		} while (d_in_lookup(dentry));
-	}
+	struct swait_queue __wait;
+
+	if (!d_in_lookup(dentry))
+		return;
+
+	INIT_LIST_HEAD(&__wait.task_list);
+	do {
+		prepare_to_swait_exclusive(dentry->d_wait, &__wait, TASK_UNINTERRUPTIBLE);
+		spin_unlock(&dentry->d_lock);
+		schedule();
+		spin_lock(&dentry->d_lock);
+	} while (d_in_lookup(dentry));
+	finish_swait(dentry->d_wait, &__wait);
 }
 
 struct dentry *d_alloc_parallel(struct dentry *parent,
 				const struct qstr *name,
-				wait_queue_head_t *wq)
+				struct swait_queue_head *wq)
 {
 	unsigned int hash = name->hash;
 	struct hlist_bl_head *b = in_lookup_hash(parent, hash);
@@ -2525,7 +2530,7 @@ struct dentry *d_alloc_parallel(struct d
 
 retry:
 	rcu_read_lock();
-	seq = smp_load_acquire(&parent->d_inode->i_dir_seq);
+	seq = smp_load_acquire(&parent->d_inode->__i_dir_seq);
 	r_seq = read_seqbegin(&rename_lock);
 	dentry = __d_lookup_rcu(parent, name, &d_seq);
 	if (unlikely(dentry)) {
@@ -2553,7 +2558,7 @@ retry:
 	}
 
 	hlist_bl_lock(b);
-	if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) {
+	if (unlikely(READ_ONCE(parent->d_inode->__i_dir_seq) != seq)) {
 		hlist_bl_unlock(b);
 		rcu_read_unlock();
 		goto retry;
@@ -2626,7 +2631,7 @@ void __d_lookup_done(struct dentry *dent
 	hlist_bl_lock(b);
 	dentry->d_flags &= ~DCACHE_PAR_LOOKUP;
 	__hlist_bl_del(&dentry->d_u.d_in_lookup_hash);
-	wake_up_all(dentry->d_wait);
+	swake_up_all(dentry->d_wait);
 	dentry->d_wait = NULL;
 	hlist_bl_unlock(b);
 	INIT_HLIST_NODE(&dentry->d_u.d_alias);
@@ -3139,6 +3144,8 @@ __setup("dhash_entries=", set_dhash_entr
 
 static void __init dcache_init_early(void)
 {
+	unsigned int loop;
+
 	/* If hashes are distributed across NUMA nodes, defer
 	 * hash allocation until vmalloc space is available.
 	 */
@@ -3155,11 +3162,16 @@ static void __init dcache_init_early(voi
 					NULL,
 					0,
 					0);
+
+	for (loop = 0; loop < (1U << d_hash_shift); loop++)
+		INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
+
 	d_hash_shift = 32 - d_hash_shift;
 }
 
 static void __init dcache_init(void)
 {
+	unsigned int loop;
 	/*
 	 * A constructor could be added for stable state like the lists,
 	 * but it is probably not worth it because of the cache nature
@@ -3183,6 +3195,10 @@ static void __init dcache_init(void)
 					NULL,
 					0,
 					0);
+
+	for (loop = 0; loop < (1U << d_hash_shift); loop++)
+		INIT_HLIST_BL_HEAD(dentry_hashtable + loop);
+
 	d_hash_shift = 32 - d_hash_shift;
 }
 
Index: linux-5.4.5-rt3/fs/eventpoll.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/eventpoll.c
+++ linux-5.4.5-rt3/fs/eventpoll.c
@@ -567,12 +567,12 @@ static int ep_poll_wakeup_proc(void *pri
 
 static void ep_poll_safewake(wait_queue_head_t *wq)
 {
-	int this_cpu = get_cpu();
+	int this_cpu = get_cpu_light();
 
 	ep_call_nested(&poll_safewake_ncalls,
 		       ep_poll_wakeup_proc, NULL, wq, (void *) (long) this_cpu);
 
-	put_cpu();
+	put_cpu_light();
 }
 
 #else
Index: linux-5.4.5-rt3/fs/ext4/page-io.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/ext4/page-io.c
+++ linux-5.4.5-rt3/fs/ext4/page-io.c
@@ -87,11 +87,10 @@ static void ext4_finish_bio(struct bio *
 		}
 		bh = head = page_buffers(page);
 		/*
-		 * We check all buffers in the page under BH_Uptodate_Lock
+		 * We check all buffers in the page under b_uptodate_lock
 		 * to avoid races with other end io clearing async_write flags
 		 */
-		local_irq_save(flags);
-		bit_spin_lock(BH_Uptodate_Lock, &head->b_state);
+		spin_lock_irqsave(&head->b_uptodate_lock, flags);
 		do {
 			if (bh_offset(bh) < bio_start ||
 			    bh_offset(bh) + bh->b_size > bio_end) {
@@ -103,8 +102,7 @@ static void ext4_finish_bio(struct bio *
 			if (bio->bi_status)
 				buffer_io_error(bh);
 		} while ((bh = bh->b_this_page) != head);
-		bit_spin_unlock(BH_Uptodate_Lock, &head->b_state);
-		local_irq_restore(flags);
+		spin_unlock_irqrestore(&head->b_uptodate_lock, flags);
 		if (!under_io) {
 			fscrypt_free_bounce_page(bounce_page);
 			end_page_writeback(page);
Index: linux-5.4.5-rt3/fs/fscache/cookie.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/fscache/cookie.c
+++ linux-5.4.5-rt3/fs/fscache/cookie.c
@@ -958,3 +958,11 @@ inconsistent:
 	return -ESTALE;
 }
 EXPORT_SYMBOL(__fscache_check_consistency);
+
+void __init fscache_cookie_init(void)
+{
+	int i;
+
+	for (i = 0; i < (1 << fscache_cookie_hash_shift) - 1; i++)
+		INIT_HLIST_BL_HEAD(&fscache_cookie_hash[i]);
+}
Index: linux-5.4.5-rt3/fs/fscache/main.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/fscache/main.c
+++ linux-5.4.5-rt3/fs/fscache/main.c
@@ -145,6 +145,7 @@ static int __init fscache_init(void)
 		ret = -ENOMEM;
 		goto error_cookie_jar;
 	}
+	fscache_cookie_init();
 
 	fscache_root = kobject_create_and_add("fscache", kernel_kobj);
 	if (!fscache_root)
Index: linux-5.4.5-rt3/fs/fuse/readdir.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/fuse/readdir.c
+++ linux-5.4.5-rt3/fs/fuse/readdir.c
@@ -158,7 +158,7 @@ static int fuse_direntplus_link(struct f
 	struct inode *dir = d_inode(parent);
 	struct fuse_conn *fc;
 	struct inode *inode;
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	if (!o->nodeid) {
 		/*
Index: linux-5.4.5-rt3/fs/inode.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/inode.c
+++ linux-5.4.5-rt3/fs/inode.c
@@ -156,7 +156,7 @@ int inode_init_always(struct super_block
 	inode->i_bdev = NULL;
 	inode->i_cdev = NULL;
 	inode->i_link = NULL;
-	inode->i_dir_seq = 0;
+	inode->__i_dir_seq = 0;
 	inode->i_rdev = 0;
 	inode->dirtied_when = 0;
 
Index: linux-5.4.5-rt3/fs/jbd2/commit.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/jbd2/commit.c
+++ linux-5.4.5-rt3/fs/jbd2/commit.c
@@ -482,10 +482,10 @@ void jbd2_journal_commit_transaction(jou
 		if (jh->b_committed_data) {
 			struct buffer_head *bh = jh2bh(jh);
 
-			jbd_lock_bh_state(bh);
+			spin_lock(&jh->b_state_lock);
 			jbd2_free(jh->b_committed_data, bh->b_size);
 			jh->b_committed_data = NULL;
-			jbd_unlock_bh_state(bh);
+			spin_unlock(&jh->b_state_lock);
 		}
 		jbd2_journal_refile_buffer(journal, jh);
 	}
@@ -920,6 +920,7 @@ restart_loop:
 		transaction_t *cp_transaction;
 		struct buffer_head *bh;
 		int try_to_free = 0;
+		bool drop_ref;
 
 		jh = commit_transaction->t_forget;
 		spin_unlock(&journal->j_list_lock);
@@ -929,7 +930,7 @@ restart_loop:
 		 * done with it.
 		 */
 		get_bh(bh);
-		jbd_lock_bh_state(bh);
+		spin_lock(&jh->b_state_lock);
 		J_ASSERT_JH(jh,	jh->b_transaction == commit_transaction);
 
 		/*
@@ -1024,8 +1025,10 @@ restart_loop:
 				try_to_free = 1;
 		}
 		JBUFFER_TRACE(jh, "refile or unfile buffer");
-		__jbd2_journal_refile_buffer(jh);
-		jbd_unlock_bh_state(bh);
+		drop_ref = __jbd2_journal_refile_buffer(jh);
+		spin_unlock(&jh->b_state_lock);
+		if (drop_ref)
+			jbd2_journal_put_journal_head(jh);
 		if (try_to_free)
 			release_buffer_page(bh);	/* Drops bh reference */
 		else
Index: linux-5.4.5-rt3/fs/jbd2/journal.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/jbd2/journal.c
+++ linux-5.4.5-rt3/fs/jbd2/journal.c
@@ -363,7 +363,7 @@ int jbd2_journal_write_metadata_buffer(t
 	/* keep subsequent assertions sane */
 	atomic_set(&new_bh->b_count, 1);
 
-	jbd_lock_bh_state(bh_in);
+	spin_lock(&jh_in->b_state_lock);
 repeat:
 	/*
 	 * If a new transaction has already done a buffer copy-out, then
@@ -405,13 +405,13 @@ repeat:
 	if (need_copy_out && !done_copy_out) {
 		char *tmp;
 
-		jbd_unlock_bh_state(bh_in);
+		spin_unlock(&jh_in->b_state_lock);
 		tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
 		if (!tmp) {
 			brelse(new_bh);
 			return -ENOMEM;
 		}
-		jbd_lock_bh_state(bh_in);
+		spin_lock(&jh_in->b_state_lock);
 		if (jh_in->b_frozen_data) {
 			jbd2_free(tmp, bh_in->b_size);
 			goto repeat;
@@ -464,7 +464,7 @@ repeat:
 	__jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
 	spin_unlock(&journal->j_list_lock);
 	set_buffer_shadow(bh_in);
-	jbd_unlock_bh_state(bh_in);
+	spin_unlock(&jh_in->b_state_lock);
 
 	return do_escape | (done_copy_out << 1);
 }
@@ -2410,6 +2410,8 @@ static struct journal_head *journal_allo
 		ret = kmem_cache_zalloc(jbd2_journal_head_cache,
 				GFP_NOFS | __GFP_NOFAIL);
 	}
+	if (ret)
+		spin_lock_init(&ret->b_state_lock);
 	return ret;
 }
 
@@ -2529,17 +2531,23 @@ static void __journal_remove_journal_hea
 	J_ASSERT_BH(bh, buffer_jbd(bh));
 	J_ASSERT_BH(bh, jh2bh(jh) == bh);
 	BUFFER_TRACE(bh, "remove journal_head");
+
+	/* Unlink before dropping the lock */
+	bh->b_private = NULL;
+	jh->b_bh = NULL;	/* debug, really */
+	clear_buffer_jbd(bh);
+}
+
+static void journal_release_journal_head(struct journal_head *jh, size_t b_size)
+{
 	if (jh->b_frozen_data) {
 		printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
-		jbd2_free(jh->b_frozen_data, bh->b_size);
+		jbd2_free(jh->b_frozen_data, b_size);
 	}
 	if (jh->b_committed_data) {
 		printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
-		jbd2_free(jh->b_committed_data, bh->b_size);
+		jbd2_free(jh->b_committed_data, b_size);
 	}
-	bh->b_private = NULL;
-	jh->b_bh = NULL;	/* debug, really */
-	clear_buffer_jbd(bh);
 	journal_free_journal_head(jh);
 }
 
@@ -2557,9 +2565,11 @@ void jbd2_journal_put_journal_head(struc
 	if (!jh->b_jcount) {
 		__journal_remove_journal_head(bh);
 		jbd_unlock_bh_journal_head(bh);
+		journal_release_journal_head(jh, bh->b_size);
 		__brelse(bh);
-	} else
+	} else {
 		jbd_unlock_bh_journal_head(bh);
+	}
 }
 
 /*
Index: linux-5.4.5-rt3/fs/jbd2/transaction.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/jbd2/transaction.c
+++ linux-5.4.5-rt3/fs/jbd2/transaction.c
@@ -879,7 +879,7 @@ repeat:
 
  	start_lock = jiffies;
 	lock_buffer(bh);
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 
 	/* If it takes too long to lock the buffer, trace it */
 	time_lock = jbd2_time_diff(start_lock, jiffies);
@@ -929,7 +929,7 @@ repeat:
 
 	error = -EROFS;
 	if (is_handle_aborted(handle)) {
-		jbd_unlock_bh_state(bh);
+		spin_unlock(&jh->b_state_lock);
 		goto out;
 	}
 	error = 0;
@@ -993,7 +993,7 @@ repeat:
 	 */
 	if (buffer_shadow(bh)) {
 		JBUFFER_TRACE(jh, "on shadow: sleep");
-		jbd_unlock_bh_state(bh);
+		spin_unlock(&jh->b_state_lock);
 		wait_on_bit_io(&bh->b_state, BH_Shadow, TASK_UNINTERRUPTIBLE);
 		goto repeat;
 	}
@@ -1014,7 +1014,7 @@ repeat:
 		JBUFFER_TRACE(jh, "generate frozen data");
 		if (!frozen_buffer) {
 			JBUFFER_TRACE(jh, "allocate memory for buffer");
-			jbd_unlock_bh_state(bh);
+			spin_unlock(&jh->b_state_lock);
 			frozen_buffer = jbd2_alloc(jh2bh(jh)->b_size,
 						   GFP_NOFS | __GFP_NOFAIL);
 			goto repeat;
@@ -1033,7 +1033,7 @@ attach_next:
 	jh->b_next_transaction = transaction;
 
 done:
-	jbd_unlock_bh_state(bh);
+	spin_unlock(&jh->b_state_lock);
 
 	/*
 	 * If we are about to journal a buffer, then any revoke pending on it is
@@ -1172,7 +1172,7 @@ int jbd2_journal_get_create_access(handl
 	 * that case: the transaction must have deleted the buffer for it to be
 	 * reused here.
 	 */
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 	J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
 		jh->b_transaction == NULL ||
 		(jh->b_transaction == journal->j_committing_transaction &&
@@ -1207,7 +1207,7 @@ int jbd2_journal_get_create_access(handl
 		jh->b_next_transaction = transaction;
 		spin_unlock(&journal->j_list_lock);
 	}
-	jbd_unlock_bh_state(bh);
+	spin_unlock(&jh->b_state_lock);
 
 	/*
 	 * akpm: I added this.  ext3_alloc_branch can pick up new indirect
@@ -1275,13 +1275,13 @@ repeat:
 		committed_data = jbd2_alloc(jh2bh(jh)->b_size,
 					    GFP_NOFS|__GFP_NOFAIL);
 
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 	if (!jh->b_committed_data) {
 		/* Copy out the current buffer contents into the
 		 * preserved, committed copy. */
 		JBUFFER_TRACE(jh, "generate b_committed data");
 		if (!committed_data) {
-			jbd_unlock_bh_state(bh);
+			spin_unlock(&jh->b_state_lock);
 			goto repeat;
 		}
 
@@ -1289,7 +1289,7 @@ repeat:
 		committed_data = NULL;
 		memcpy(jh->b_committed_data, bh->b_data, bh->b_size);
 	}
-	jbd_unlock_bh_state(bh);
+	spin_unlock(&jh->b_state_lock);
 out:
 	jbd2_journal_put_journal_head(jh);
 	if (unlikely(committed_data))
@@ -1390,16 +1390,16 @@ int jbd2_journal_dirty_metadata(handle_t
 	 */
 	if (jh->b_transaction != transaction &&
 	    jh->b_next_transaction != transaction) {
-		jbd_lock_bh_state(bh);
+		spin_lock(&jh->b_state_lock);
 		J_ASSERT_JH(jh, jh->b_transaction == transaction ||
 				jh->b_next_transaction == transaction);
-		jbd_unlock_bh_state(bh);
+		spin_unlock(&jh->b_state_lock);
 	}
 	if (jh->b_modified == 1) {
 		/* If it's in our transaction it must be in BJ_Metadata list. */
 		if (jh->b_transaction == transaction &&
 		    jh->b_jlist != BJ_Metadata) {
-			jbd_lock_bh_state(bh);
+			spin_lock(&jh->b_state_lock);
 			if (jh->b_transaction == transaction &&
 			    jh->b_jlist != BJ_Metadata)
 				pr_err("JBD2: assertion failure: h_type=%u "
@@ -1409,13 +1409,13 @@ int jbd2_journal_dirty_metadata(handle_t
 				       jh->b_jlist);
 			J_ASSERT_JH(jh, jh->b_transaction != transaction ||
 					jh->b_jlist == BJ_Metadata);
-			jbd_unlock_bh_state(bh);
+			spin_unlock(&jh->b_state_lock);
 		}
 		goto out;
 	}
 
 	journal = transaction->t_journal;
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 
 	if (jh->b_modified == 0) {
 		/*
@@ -1501,7 +1501,7 @@ int jbd2_journal_dirty_metadata(handle_t
 	__jbd2_journal_file_buffer(jh, transaction, BJ_Metadata);
 	spin_unlock(&journal->j_list_lock);
 out_unlock_bh:
-	jbd_unlock_bh_state(bh);
+	spin_unlock(&jh->b_state_lock);
 out:
 	JBUFFER_TRACE(jh, "exit");
 	return ret;
@@ -1539,18 +1539,20 @@ int jbd2_journal_forget (handle_t *handl
 
 	BUFFER_TRACE(bh, "entry");
 
-	jbd_lock_bh_state(bh);
+	jh = jbd2_journal_grab_journal_head(bh);
+	if (!jh) {
+		__bforget(bh);
+		return 0;
+	}
 
-	if (!buffer_jbd(bh))
-		goto not_jbd;
-	jh = bh2jh(bh);
+	spin_lock(&jh->b_state_lock);
 
 	/* Critical error: attempting to delete a bitmap buffer, maybe?
 	 * Don't do any jbd operations, and return an error. */
 	if (!J_EXPECT_JH(jh, !jh->b_committed_data,
 			 "inconsistent data on disk")) {
 		err = -EIO;
-		goto not_jbd;
+		goto drop;
 	}
 
 	/* keep track of whether or not this transaction modified us */
@@ -1598,10 +1600,7 @@ int jbd2_journal_forget (handle_t *handl
 			__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
 		} else {
 			__jbd2_journal_unfile_buffer(jh);
-			if (!buffer_jbd(bh)) {
-				spin_unlock(&journal->j_list_lock);
-				goto not_jbd;
-			}
+			jbd2_journal_put_journal_head(jh);
 		}
 		spin_unlock(&journal->j_list_lock);
 	} else if (jh->b_transaction) {
@@ -1643,7 +1642,7 @@ int jbd2_journal_forget (handle_t *handl
 		if (!jh->b_cp_transaction) {
 			JBUFFER_TRACE(jh, "belongs to none transaction");
 			spin_unlock(&journal->j_list_lock);
-			goto not_jbd;
+			goto drop;
 		}
 
 		/*
@@ -1653,7 +1652,7 @@ int jbd2_journal_forget (handle_t *handl
 		if (!buffer_dirty(bh)) {
 			__jbd2_journal_remove_checkpoint(jh);
 			spin_unlock(&journal->j_list_lock);
-			goto not_jbd;
+			goto drop;
 		}
 
 		/*
@@ -1666,20 +1665,15 @@ int jbd2_journal_forget (handle_t *handl
 		__jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
 		spin_unlock(&journal->j_list_lock);
 	}
-
-	jbd_unlock_bh_state(bh);
-	__brelse(bh);
 drop:
+	__brelse(bh);
+	spin_unlock(&jh->b_state_lock);
+	jbd2_journal_put_journal_head(jh);
 	if (drop_reserve) {
 		/* no need to reserve log space for this block -bzzz */
 		handle->h_buffer_credits++;
 	}
 	return err;
-
-not_jbd:
-	jbd_unlock_bh_state(bh);
-	__bforget(bh);
-	goto drop;
 }
 
 /**
@@ -1878,7 +1872,7 @@ free_and_exit:
  *
  * j_list_lock is held.
  *
- * jbd_lock_bh_state(jh2bh(jh)) is held.
+ * jh->b_state_lock is held.
  */
 
 static inline void
@@ -1902,7 +1896,7 @@ __blist_add_buffer(struct journal_head *
  *
  * Called with j_list_lock held, and the journal may not be locked.
  *
- * jbd_lock_bh_state(jh2bh(jh)) is held.
+ * jh->b_state_lock is held.
  */
 
 static inline void
@@ -1934,7 +1928,7 @@ static void __jbd2_journal_temp_unlink_b
 	transaction_t *transaction;
 	struct buffer_head *bh = jh2bh(jh);
 
-	J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
+	lockdep_assert_held(&jh->b_state_lock);
 	transaction = jh->b_transaction;
 	if (transaction)
 		assert_spin_locked(&transaction->t_journal->j_list_lock);
@@ -1971,17 +1965,15 @@ static void __jbd2_journal_temp_unlink_b
 }
 
 /*
- * Remove buffer from all transactions.
+ * Remove buffer from all transactions. The caller is responsible for dropping
+ * the jh reference that belonged to the transaction.
  *
  * Called with bh_state lock and j_list_lock
- *
- * jh and bh may be already freed when this function returns.
  */
 static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
 {
 	__jbd2_journal_temp_unlink_buffer(jh);
 	jh->b_transaction = NULL;
-	jbd2_journal_put_journal_head(jh);
 }
 
 void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
@@ -1990,18 +1982,19 @@ void jbd2_journal_unfile_buffer(journal_
 
 	/* Get reference so that buffer cannot be freed before we unlock it */
 	get_bh(bh);
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 	spin_lock(&journal->j_list_lock);
 	__jbd2_journal_unfile_buffer(jh);
 	spin_unlock(&journal->j_list_lock);
-	jbd_unlock_bh_state(bh);
+	spin_unlock(&jh->b_state_lock);
+	jbd2_journal_put_journal_head(jh);
 	__brelse(bh);
 }
 
 /*
  * Called from jbd2_journal_try_to_free_buffers().
  *
- * Called under jbd_lock_bh_state(bh)
+ * Called under jh->b_state_lock
  */
 static void
 __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
@@ -2088,10 +2081,10 @@ int jbd2_journal_try_to_free_buffers(jou
 		if (!jh)
 			continue;
 
-		jbd_lock_bh_state(bh);
+		spin_lock(&jh->b_state_lock);
 		__journal_try_to_free_buffer(journal, bh);
+		spin_unlock(&jh->b_state_lock);
 		jbd2_journal_put_journal_head(jh);
-		jbd_unlock_bh_state(bh);
 		if (buffer_jbd(bh))
 			goto busy;
 	} while ((bh = bh->b_this_page) != head);
@@ -2112,7 +2105,7 @@ busy:
  *
  * Called under j_list_lock.
  *
- * Called under jbd_lock_bh_state(bh).
+ * Called under jh->b_state_lock.
  */
 static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction)
 {
@@ -2133,6 +2126,7 @@ static int __dispose_buffer(struct journ
 	} else {
 		JBUFFER_TRACE(jh, "on running transaction");
 		__jbd2_journal_unfile_buffer(jh);
+		jbd2_journal_put_journal_head(jh);
 	}
 	return may_free;
 }
@@ -2199,18 +2193,15 @@ static int journal_unmap_buffer(journal_
 	 * holding the page lock. --sct
 	 */
 
-	if (!buffer_jbd(bh))
+	jh = jbd2_journal_grab_journal_head(bh);
+	if (!jh)
 		goto zap_buffer_unlocked;
 
 	/* OK, we have data buffer in journaled mode */
 	write_lock(&journal->j_state_lock);
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 	spin_lock(&journal->j_list_lock);
 
-	jh = jbd2_journal_grab_journal_head(bh);
-	if (!jh)
-		goto zap_buffer_no_jh;
-
 	/*
 	 * We cannot remove the buffer from checkpoint lists until the
 	 * transaction adding inode to orphan list (let's call it T)
@@ -2289,10 +2280,10 @@ static int journal_unmap_buffer(journal_
 		 * for commit and try again.
 		 */
 		if (partial_page) {
-			jbd2_journal_put_journal_head(jh);
 			spin_unlock(&journal->j_list_lock);
-			jbd_unlock_bh_state(bh);
+			spin_unlock(&jh->b_state_lock);
 			write_unlock(&journal->j_state_lock);
+			jbd2_journal_put_journal_head(jh);
 			return -EBUSY;
 		}
 		/*
@@ -2304,10 +2295,10 @@ static int journal_unmap_buffer(journal_
 		set_buffer_freed(bh);
 		if (journal->j_running_transaction && buffer_jbddirty(bh))
 			jh->b_next_transaction = journal->j_running_transaction;
-		jbd2_journal_put_journal_head(jh);
 		spin_unlock(&journal->j_list_lock);
-		jbd_unlock_bh_state(bh);
+		spin_unlock(&jh->b_state_lock);
 		write_unlock(&journal->j_state_lock);
+		jbd2_journal_put_journal_head(jh);
 		return 0;
 	} else {
 		/* Good, the buffer belongs to the running transaction.
@@ -2331,11 +2322,10 @@ zap_buffer:
 	 * here.
 	 */
 	jh->b_modified = 0;
-	jbd2_journal_put_journal_head(jh);
-zap_buffer_no_jh:
 	spin_unlock(&journal->j_list_lock);
-	jbd_unlock_bh_state(bh);
+	spin_unlock(&jh->b_state_lock);
 	write_unlock(&journal->j_state_lock);
+	jbd2_journal_put_journal_head(jh);
 zap_buffer_unlocked:
 	clear_buffer_dirty(bh);
 	J_ASSERT_BH(bh, !buffer_jbddirty(bh));
@@ -2422,7 +2412,7 @@ void __jbd2_journal_file_buffer(struct j
 	int was_dirty = 0;
 	struct buffer_head *bh = jh2bh(jh);
 
-	J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
+	lockdep_assert_held(&jh->b_state_lock);
 	assert_spin_locked(&transaction->t_journal->j_list_lock);
 
 	J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
@@ -2484,11 +2474,11 @@ void __jbd2_journal_file_buffer(struct j
 void jbd2_journal_file_buffer(struct journal_head *jh,
 				transaction_t *transaction, int jlist)
 {
-	jbd_lock_bh_state(jh2bh(jh));
+	spin_lock(&jh->b_state_lock);
 	spin_lock(&transaction->t_journal->j_list_lock);
 	__jbd2_journal_file_buffer(jh, transaction, jlist);
 	spin_unlock(&transaction->t_journal->j_list_lock);
-	jbd_unlock_bh_state(jh2bh(jh));
+	spin_unlock(&jh->b_state_lock);
 }
 
 /*
@@ -2498,23 +2488,25 @@ void jbd2_journal_file_buffer(struct jou
  * buffer on that transaction's metadata list.
  *
  * Called under j_list_lock
- * Called under jbd_lock_bh_state(jh2bh(jh))
+ * Called under jh->b_state_lock
  *
- * jh and bh may be already free when this function returns
+ * When this function returns true, there's no next transaction to refile to
+ * and the caller has to drop jh reference through
+ * jbd2_journal_put_journal_head().
  */
-void __jbd2_journal_refile_buffer(struct journal_head *jh)
+bool __jbd2_journal_refile_buffer(struct journal_head *jh)
 {
 	int was_dirty, jlist;
 	struct buffer_head *bh = jh2bh(jh);
 
-	J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
+	lockdep_assert_held(&jh->b_state_lock);
 	if (jh->b_transaction)
 		assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
 
 	/* If the buffer is now unused, just drop it. */
 	if (jh->b_next_transaction == NULL) {
 		__jbd2_journal_unfile_buffer(jh);
-		return;
+		return true;
 	}
 
 	/*
@@ -2542,6 +2534,7 @@ void __jbd2_journal_refile_buffer(struct
 
 	if (was_dirty)
 		set_buffer_jbddirty(bh);
+	return false;
 }
 
 /*
@@ -2552,16 +2545,15 @@ void __jbd2_journal_refile_buffer(struct
  */
 void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
 {
-	struct buffer_head *bh = jh2bh(jh);
+	bool drop;
 
-	/* Get reference so that buffer cannot be freed before we unlock it */
-	get_bh(bh);
-	jbd_lock_bh_state(bh);
+	spin_lock(&jh->b_state_lock);
 	spin_lock(&journal->j_list_lock);
-	__jbd2_journal_refile_buffer(jh);
-	jbd_unlock_bh_state(bh);
+	drop = __jbd2_journal_refile_buffer(jh);
+	spin_unlock(&jh->b_state_lock);
 	spin_unlock(&journal->j_list_lock);
-	__brelse(bh);
+	if (drop)
+		jbd2_journal_put_journal_head(jh);
 }
 
 /*
Index: linux-5.4.5-rt3/fs/namei.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/namei.c
+++ linux-5.4.5-rt3/fs/namei.c
@@ -1638,7 +1638,7 @@ static struct dentry *__lookup_slow(cons
 {
 	struct dentry *dentry, *old;
 	struct inode *inode = dir->d_inode;
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	/* Don't go there if it's already dead */
 	if (unlikely(IS_DEADDIR(inode)))
@@ -3126,7 +3126,7 @@ static int lookup_open(struct nameidata
 	struct dentry *dentry;
 	int error, create_error = 0;
 	umode_t mode = op->mode;
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 
 	if (unlikely(IS_DEADDIR(dir_inode)))
 		return -ENOENT;
Index: linux-5.4.5-rt3/fs/namespace.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/namespace.c
+++ linux-5.4.5-rt3/fs/namespace.c
@@ -14,6 +14,7 @@
 #include <linux/mnt_namespace.h>
 #include <linux/user_namespace.h>
 #include <linux/namei.h>
+#include <linux/delay.h>
 #include <linux/security.h>
 #include <linux/cred.h>
 #include <linux/idr.h>
@@ -321,8 +322,11 @@ int __mnt_want_write(struct vfsmount *m)
 	 * incremented count after it has set MNT_WRITE_HOLD.
 	 */
 	smp_mb();
-	while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD)
-		cpu_relax();
+	while (READ_ONCE(mnt->mnt.mnt_flags) & MNT_WRITE_HOLD) {
+		preempt_enable();
+		cpu_chill();
+		preempt_disable();
+	}
 	/*
 	 * After the slowpath clears MNT_WRITE_HOLD, mnt_is_readonly will
 	 * be set to match its requirements. So we must not load that until
Index: linux-5.4.5-rt3/fs/nfs/delegation.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/delegation.c
+++ linux-5.4.5-rt3/fs/nfs/delegation.c
@@ -162,11 +162,11 @@ again:
 		sp = state->owner;
 		/* Block nfs4_proc_unlck */
 		mutex_lock(&sp->so_delegreturn_mutex);
-		seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
+		seq = read_seqbegin(&sp->so_reclaim_seqlock);
 		err = nfs4_open_delegation_recall(ctx, state, stateid);
 		if (!err)
 			err = nfs_delegation_claim_locks(state, stateid);
-		if (!err && read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
+		if (!err && read_seqretry(&sp->so_reclaim_seqlock, seq))
 			err = -EAGAIN;
 		mutex_unlock(&sp->so_delegreturn_mutex);
 		put_nfs_open_context(ctx);
Index: linux-5.4.5-rt3/fs/nfs/dir.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/dir.c
+++ linux-5.4.5-rt3/fs/nfs/dir.c
@@ -445,7 +445,7 @@ static
 void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
 {
 	struct qstr filename = QSTR_INIT(entry->name, entry->len);
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 	struct dentry *dentry;
 	struct dentry *alias;
 	struct inode *dir = d_inode(parent);
@@ -1496,7 +1496,7 @@ int nfs_atomic_open(struct inode *dir, s
 		    struct file *file, unsigned open_flags,
 		    umode_t mode)
 {
-	DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+	DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 	struct nfs_open_context *ctx;
 	struct dentry *res;
 	struct iattr attr = { .ia_valid = ATTR_OPEN };
@@ -1825,7 +1825,11 @@ int nfs_rmdir(struct inode *dir, struct
 
 	trace_nfs_rmdir_enter(dir, dentry);
 	if (d_really_is_positive(dentry)) {
+#ifdef CONFIG_PREEMPT_RT
+		down(&NFS_I(d_inode(dentry))->rmdir_sem);
+#else
 		down_write(&NFS_I(d_inode(dentry))->rmdir_sem);
+#endif
 		error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
 		/* Ensure the VFS deletes this inode */
 		switch (error) {
@@ -1835,7 +1839,11 @@ int nfs_rmdir(struct inode *dir, struct
 		case -ENOENT:
 			nfs_dentry_handle_enoent(dentry);
 		}
+#ifdef CONFIG_PREEMPT_RT
+		up(&NFS_I(d_inode(dentry))->rmdir_sem);
+#else
 		up_write(&NFS_I(d_inode(dentry))->rmdir_sem);
+#endif
 	} else
 		error = NFS_PROTO(dir)->rmdir(dir, &dentry->d_name);
 	trace_nfs_rmdir_exit(dir, dentry, error);
Index: linux-5.4.5-rt3/fs/nfs/inode.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/inode.c
+++ linux-5.4.5-rt3/fs/nfs/inode.c
@@ -2105,7 +2105,11 @@ static void init_once(void *foo)
 	atomic_long_set(&nfsi->nrequests, 0);
 	atomic_long_set(&nfsi->commit_info.ncommit, 0);
 	atomic_set(&nfsi->commit_info.rpcs_out, 0);
+#ifdef CONFIG_PREEMPT_RT
+	sema_init(&nfsi->rmdir_sem, 1);
+#else
 	init_rwsem(&nfsi->rmdir_sem);
+#endif
 	mutex_init(&nfsi->commit_mutex);
 	nfs4_init_once(nfsi);
 }
Index: linux-5.4.5-rt3/fs/nfs/nfs4_fs.h
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/nfs4_fs.h
+++ linux-5.4.5-rt3/fs/nfs/nfs4_fs.h
@@ -115,7 +115,7 @@ struct nfs4_state_owner {
 	unsigned long	     so_flags;
 	struct list_head     so_states;
 	struct nfs_seqid_counter so_seqid;
-	seqcount_t	     so_reclaim_seqcount;
+	seqlock_t	     so_reclaim_seqlock;
 	struct mutex	     so_delegreturn_mutex;
 };
 
Index: linux-5.4.5-rt3/fs/nfs/nfs4proc.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/nfs4proc.c
+++ linux-5.4.5-rt3/fs/nfs/nfs4proc.c
@@ -2965,7 +2965,7 @@ static int _nfs4_open_and_get_state(stru
 	unsigned int seq;
 	int ret;
 
-	seq = raw_seqcount_begin(&sp->so_reclaim_seqcount);
+	seq = raw_seqcount_begin(&sp->so_reclaim_seqlock.seqcount);
 
 	ret = _nfs4_proc_open(opendata, ctx);
 	if (ret != 0)
@@ -3007,7 +3007,7 @@ static int _nfs4_open_and_get_state(stru
 
 	if (d_inode(dentry) == state->inode) {
 		nfs_inode_attach_open_context(ctx);
-		if (read_seqcount_retry(&sp->so_reclaim_seqcount, seq))
+		if (read_seqretry(&sp->so_reclaim_seqlock, seq))
 			nfs4_schedule_stateid_recovery(server, state);
 	}
 
Index: linux-5.4.5-rt3/fs/nfs/nfs4state.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/nfs4state.c
+++ linux-5.4.5-rt3/fs/nfs/nfs4state.c
@@ -510,7 +510,7 @@ nfs4_alloc_state_owner(struct nfs_server
 	nfs4_init_seqid_counter(&sp->so_seqid);
 	atomic_set(&sp->so_count, 1);
 	INIT_LIST_HEAD(&sp->so_lru);
-	seqcount_init(&sp->so_reclaim_seqcount);
+	seqlock_init(&sp->so_reclaim_seqlock);
 	mutex_init(&sp->so_delegreturn_mutex);
 	return sp;
 }
@@ -1618,8 +1618,12 @@ static int nfs4_reclaim_open_state(struc
 	 * recovering after a network partition or a reboot from a
 	 * server that doesn't support a grace period.
 	 */
+#ifdef CONFIG_PREEMPT_RT
+	write_seqlock(&sp->so_reclaim_seqlock);
+#else
+	write_seqcount_begin(&sp->so_reclaim_seqlock.seqcount);
+#endif
 	spin_lock(&sp->so_lock);
-	raw_write_seqcount_begin(&sp->so_reclaim_seqcount);
 restart:
 	list_for_each_entry(state, &sp->so_states, open_states) {
 		if (!test_and_clear_bit(ops->state_flag_bit, &state->flags))
@@ -1680,14 +1684,20 @@ restart:
 		spin_lock(&sp->so_lock);
 		goto restart;
 	}
-	raw_write_seqcount_end(&sp->so_reclaim_seqcount);
 	spin_unlock(&sp->so_lock);
+#ifdef CONFIG_PREEMPT_RT
+	write_sequnlock(&sp->so_reclaim_seqlock);
+#else
+	write_seqcount_end(&sp->so_reclaim_seqlock.seqcount);
+#endif
 	return 0;
 out_err:
 	nfs4_put_open_state(state);
-	spin_lock(&sp->so_lock);
-	raw_write_seqcount_end(&sp->so_reclaim_seqcount);
-	spin_unlock(&sp->so_lock);
+#ifdef CONFIG_PREEMPT_RT
+	write_sequnlock(&sp->so_reclaim_seqlock);
+#else
+	write_seqcount_end(&sp->so_reclaim_seqlock.seqcount);
+#endif
 	return status;
 }
 
Index: linux-5.4.5-rt3/fs/nfs/unlink.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/nfs/unlink.c
+++ linux-5.4.5-rt3/fs/nfs/unlink.c
@@ -13,7 +13,7 @@
 #include <linux/sunrpc/clnt.h>
 #include <linux/nfs_fs.h>
 #include <linux/sched.h>
-#include <linux/wait.h>
+#include <linux/swait.h>
 #include <linux/namei.h>
 #include <linux/fsnotify.h>
 
@@ -53,6 +53,29 @@ static void nfs_async_unlink_done(struct
 		rpc_restart_call_prepare(task);
 }
 
+#ifdef CONFIG_PREEMPT_RT
+static void nfs_down_anon(struct semaphore *sema)
+{
+	down(sema);
+}
+
+static void nfs_up_anon(struct semaphore *sema)
+{
+	up(sema);
+}
+
+#else
+static void nfs_down_anon(struct rw_semaphore *rwsem)
+{
+	down_read_non_owner(rwsem);
+}
+
+static void nfs_up_anon(struct rw_semaphore *rwsem)
+{
+	up_read_non_owner(rwsem);
+}
+#endif
+
 /**
  * nfs_async_unlink_release - Release the sillydelete data.
  * @calldata: struct nfs_unlinkdata to release
@@ -66,7 +89,7 @@ static void nfs_async_unlink_release(voi
 	struct dentry *dentry = data->dentry;
 	struct super_block *sb = dentry->d_sb;
 
-	up_read_non_owner(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
+	nfs_up_anon(&NFS_I(d_inode(dentry->d_parent))->rmdir_sem);
 	d_lookup_done(dentry);
 	nfs_free_unlinkdata(data);
 	dput(dentry);
@@ -119,10 +142,10 @@ static int nfs_call_unlink(struct dentry
 	struct inode *dir = d_inode(dentry->d_parent);
 	struct dentry *alias;
 
-	down_read_non_owner(&NFS_I(dir)->rmdir_sem);
+	nfs_down_anon(&NFS_I(dir)->rmdir_sem);
 	alias = d_alloc_parallel(dentry->d_parent, &data->args.name, &data->wq);
 	if (IS_ERR(alias)) {
-		up_read_non_owner(&NFS_I(dir)->rmdir_sem);
+		nfs_up_anon(&NFS_I(dir)->rmdir_sem);
 		return 0;
 	}
 	if (!d_in_lookup(alias)) {
@@ -144,7 +167,7 @@ static int nfs_call_unlink(struct dentry
 			ret = 0;
 		spin_unlock(&alias->d_lock);
 		dput(alias);
-		up_read_non_owner(&NFS_I(dir)->rmdir_sem);
+		nfs_up_anon(&NFS_I(dir)->rmdir_sem);
 		/*
 		 * If we'd displaced old cached devname, free it.  At that
 		 * point dentry is definitely not a root, so we won't need
@@ -180,7 +203,7 @@ nfs_async_unlink(struct dentry *dentry,
 
 	data->cred = get_current_cred();
 	data->res.dir_attr = &data->dir_attr;
-	init_waitqueue_head(&data->wq);
+	init_swait_queue_head(&data->wq);
 
 	status = -EBUSY;
 	spin_lock(&dentry->d_lock);
Index: linux-5.4.5-rt3/fs/ntfs/aops.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/ntfs/aops.c
+++ linux-5.4.5-rt3/fs/ntfs/aops.c
@@ -92,8 +92,7 @@ static void ntfs_end_buffer_async_read(s
 				"0x%llx.", (unsigned long long)bh->b_blocknr);
 	}
 	first = page_buffers(page);
-	local_irq_save(flags);
-	bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
+	spin_lock_irqsave(&first->b_uptodate_lock, flags);
 	clear_buffer_async_read(bh);
 	unlock_buffer(bh);
 	tmp = bh;
@@ -108,8 +107,7 @@ static void ntfs_end_buffer_async_read(s
 		}
 		tmp = tmp->b_this_page;
 	} while (tmp != bh);
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
 	/*
 	 * If none of the buffers had errors then we can set the page uptodate,
 	 * but we first have to perform the post read mst fixups, if the
@@ -142,8 +140,7 @@ static void ntfs_end_buffer_async_read(s
 	unlock_page(page);
 	return;
 still_busy:
-	bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
-	local_irq_restore(flags);
+	spin_unlock_irqrestore(&first->b_uptodate_lock, flags);
 	return;
 }
 
Index: linux-5.4.5-rt3/fs/ocfs2/suballoc.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/ocfs2/suballoc.c
+++ linux-5.4.5-rt3/fs/ocfs2/suballoc.c
@@ -1252,6 +1252,7 @@ static int ocfs2_test_bg_bit_allocatable
 					 int nr)
 {
 	struct ocfs2_group_desc *bg = (struct ocfs2_group_desc *) bg_bh->b_data;
+	struct journal_head *jh;
 	int ret;
 
 	if (ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap))
@@ -1260,13 +1261,14 @@ static int ocfs2_test_bg_bit_allocatable
 	if (!buffer_jbd(bg_bh))
 		return 1;
 
-	jbd_lock_bh_state(bg_bh);
-	bg = (struct ocfs2_group_desc *) bh2jh(bg_bh)->b_committed_data;
+	jh = bh2jh(bg_bh);
+	spin_lock(&jh->b_state_lock);
+	bg = (struct ocfs2_group_desc *) jh->b_committed_data;
 	if (bg)
 		ret = !ocfs2_test_bit(nr, (unsigned long *)bg->bg_bitmap);
 	else
 		ret = 1;
-	jbd_unlock_bh_state(bg_bh);
+	spin_unlock(&jh->b_state_lock);
 
 	return ret;
 }
@@ -2387,6 +2389,7 @@ static int ocfs2_block_group_clear_bits(
 	int status;
 	unsigned int tmp;
 	struct ocfs2_group_desc *undo_bg = NULL;
+	struct journal_head *jh;
 
 	/* The caller got this descriptor from
 	 * ocfs2_read_group_descriptor().  Any corruption is a code bug. */
@@ -2405,10 +2408,10 @@ static int ocfs2_block_group_clear_bits(
 		goto bail;
 	}
 
+	jh = bh2jh(group_bh);
 	if (undo_fn) {
-		jbd_lock_bh_state(group_bh);
-		undo_bg = (struct ocfs2_group_desc *)
-					bh2jh(group_bh)->b_committed_data;
+		spin_lock(&jh->b_state_lock);
+		undo_bg = (struct ocfs2_group_desc *) jh->b_committed_data;
 		BUG_ON(!undo_bg);
 	}
 
@@ -2423,7 +2426,7 @@ static int ocfs2_block_group_clear_bits(
 	le16_add_cpu(&bg->bg_free_bits_count, num_bits);
 	if (le16_to_cpu(bg->bg_free_bits_count) > le16_to_cpu(bg->bg_bits)) {
 		if (undo_fn)
-			jbd_unlock_bh_state(group_bh);
+			spin_unlock(&jh->b_state_lock);
 		return ocfs2_error(alloc_inode->i_sb, "Group descriptor # %llu has bit count %u but claims %u are freed. num_bits %d\n",
 				   (unsigned long long)le64_to_cpu(bg->bg_blkno),
 				   le16_to_cpu(bg->bg_bits),
@@ -2432,7 +2435,7 @@ static int ocfs2_block_group_clear_bits(
 	}
 
 	if (undo_fn)
-		jbd_unlock_bh_state(group_bh);
+		spin_unlock(&jh->b_state_lock);
 
 	ocfs2_journal_dirty(handle, group_bh);
 bail:
Index: linux-5.4.5-rt3/fs/proc/base.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/proc/base.c
+++ linux-5.4.5-rt3/fs/proc/base.c
@@ -1891,7 +1891,7 @@ bool proc_fill_cache(struct file *file,
 
 	child = d_hash_and_lookup(dir, &qname);
 	if (!child) {
-		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 		child = d_alloc_parallel(dir, &qname, &wq);
 		if (IS_ERR(child))
 			goto end_instantiate;
Index: linux-5.4.5-rt3/fs/proc/kmsg.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/proc/kmsg.c
+++ linux-5.4.5-rt3/fs/proc/kmsg.c
@@ -18,8 +18,6 @@
 #include <linux/uaccess.h>
 #include <asm/io.h>
 
-extern wait_queue_head_t log_wait;
-
 static int kmsg_open(struct inode * inode, struct file * file)
 {
 	return do_syslog(SYSLOG_ACTION_OPEN, NULL, 0, SYSLOG_FROM_PROC);
@@ -42,7 +40,7 @@ static ssize_t kmsg_read(struct file *fi
 
 static __poll_t kmsg_poll(struct file *file, poll_table *wait)
 {
-	poll_wait(file, &log_wait, wait);
+	poll_wait(file, printk_wait_queue(), wait);
 	if (do_syslog(SYSLOG_ACTION_SIZE_UNREAD, NULL, 0, SYSLOG_FROM_PROC))
 		return EPOLLIN | EPOLLRDNORM;
 	return 0;
Index: linux-5.4.5-rt3/fs/proc/proc_sysctl.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/proc/proc_sysctl.c
+++ linux-5.4.5-rt3/fs/proc/proc_sysctl.c
@@ -702,7 +702,7 @@ static bool proc_sys_fill_cache(struct f
 
 	child = d_lookup(dir, &qname);
 	if (!child) {
-		DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wq);
+		DECLARE_SWAIT_QUEUE_HEAD_ONSTACK(wq);
 		child = d_alloc_parallel(dir, &qname, &wq);
 		if (IS_ERR(child))
 			return false;
Index: linux-5.4.5-rt3/fs/squashfs/decompressor_multi_percpu.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/squashfs/decompressor_multi_percpu.c
+++ linux-5.4.5-rt3/fs/squashfs/decompressor_multi_percpu.c
@@ -8,6 +8,7 @@
 #include <linux/slab.h>
 #include <linux/percpu.h>
 #include <linux/buffer_head.h>
+#include <linux/locallock.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
@@ -23,6 +24,8 @@ struct squashfs_stream {
 	void		*stream;
 };
 
+static DEFINE_LOCAL_IRQ_LOCK(stream_lock);
+
 void *squashfs_decompressor_create(struct squashfs_sb_info *msblk,
 						void *comp_opts)
 {
@@ -77,10 +80,15 @@ int squashfs_decompress(struct squashfs_
 {
 	struct squashfs_stream __percpu *percpu =
 			(struct squashfs_stream __percpu *) msblk->stream;
-	struct squashfs_stream *stream = get_cpu_ptr(percpu);
-	int res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
-		offset, length, output);
-	put_cpu_ptr(stream);
+	struct squashfs_stream *stream;
+	int res;
+
+	stream = get_locked_ptr(stream_lock, percpu);
+
+	res = msblk->decompressor->decompress(msblk, stream->stream, bh, b,
+			offset, length, output);
+
+	put_locked_ptr(stream_lock, stream);
 
 	if (res < 0)
 		ERROR("%s decompression failed, data probably corrupt\n",
Index: linux-5.4.5-rt3/fs/stack.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/stack.c
+++ linux-5.4.5-rt3/fs/stack.c
@@ -23,7 +23,7 @@ void fsstack_copy_inode_size(struct inod
 
 	/*
 	 * But on 32-bit, we ought to make an effort to keep the two halves of
-	 * i_blocks in sync despite SMP or PREEMPT - though stat's
+	 * i_blocks in sync despite SMP or PREEMPTION - though stat's
 	 * generic_fillattr() doesn't bother, and we won't be applying quotas
 	 * (where i_blocks does become important) at the upper level.
 	 *
@@ -38,14 +38,14 @@ void fsstack_copy_inode_size(struct inod
 		spin_unlock(&src->i_lock);
 
 	/*
-	 * If CONFIG_SMP or CONFIG_PREEMPT on 32-bit, it's vital for
+	 * If CONFIG_SMP or CONFIG_PREEMPTION on 32-bit, it's vital for
 	 * fsstack_copy_inode_size() to hold some lock around
 	 * i_size_write(), otherwise i_size_read() may spin forever (see
 	 * include/linux/fs.h).  We don't necessarily hold i_mutex when this
 	 * is called, so take i_lock for that case.
 	 *
 	 * And if on 32-bit, continue our effort to keep the two halves of
-	 * i_blocks in sync despite SMP or PREEMPT: use i_lock  for that case
+	 * i_blocks in sync despite SMP or PREEMPTION: use i_lock for that case
 	 * too, and do both at once by combining the tests.
 	 *
 	 * There is none of this locking overhead in the 64-bit case.
Index: linux-5.4.5-rt3/fs/userfaultfd.c
===================================================================
--- linux-5.4.5-rt3.orig/fs/userfaultfd.c
+++ linux-5.4.5-rt3/fs/userfaultfd.c
@@ -61,7 +61,7 @@ struct userfaultfd_ctx {
 	/* waitqueue head for events */
 	wait_queue_head_t event_wqh;
 	/* a refile sequence protected by fault_pending_wqh lock */
-	struct seqcount refile_seq;
+	seqlock_t refile_seq;
 	/* pseudo fd refcounting */
 	refcount_t refcount;
 	/* userfaultfd syscall flags */
@@ -1063,7 +1063,7 @@ static ssize_t userfaultfd_ctx_read(stru
 			 * waitqueue could become empty if this is the
 			 * only userfault.
 			 */
-			write_seqcount_begin(&ctx->refile_seq);
+			write_seqlock(&ctx->refile_seq);
 
 			/*
 			 * The fault_pending_wqh.lock prevents the uwq
@@ -1089,7 +1089,7 @@ static ssize_t userfaultfd_ctx_read(stru
 			list_del(&uwq->wq.entry);
 			add_wait_queue(&ctx->fault_wqh, &uwq->wq);
 
-			write_seqcount_end(&ctx->refile_seq);
+			write_sequnlock(&ctx->refile_seq);
 
 			/* careful to always initialize msg if ret == 0 */
 			*msg = uwq->msg;
@@ -1262,11 +1262,11 @@ static __always_inline void wake_userfau
 	 * sure we've userfaults to wake.
 	 */
 	do {
-		seq = read_seqcount_begin(&ctx->refile_seq);
+		seq = read_seqbegin(&ctx->refile_seq);
 		need_wakeup = waitqueue_active(&ctx->fault_pending_wqh) ||
 			waitqueue_active(&ctx->fault_wqh);
 		cond_resched();
-	} while (read_seqcount_retry(&ctx->refile_seq, seq));
+	} while (read_seqretry(&ctx->refile_seq, seq));
 	if (need_wakeup)
 		__wake_userfault(ctx, range);
 }
@@ -1939,7 +1939,7 @@ static void init_once_userfaultfd_ctx(vo
 	init_waitqueue_head(&ctx->fault_wqh);
 	init_waitqueue_head(&ctx->event_wqh);
 	init_waitqueue_head(&ctx->fd_wqh);
-	seqcount_init(&ctx->refile_seq);
+	seqlock_init(&ctx->refile_seq);
 }
 
 SYSCALL_DEFINE1(userfaultfd, int, flags)
Index: linux-5.4.5-rt3/include/Kbuild
===================================================================
--- linux-5.4.5-rt3.orig/include/Kbuild
+++ linux-5.4.5-rt3/include/Kbuild
@@ -1158,8 +1158,15 @@ header-test-			+= xen/xenbus.h
 # Do not include directly
 header-test- += linux/compiler-clang.h
 header-test- += linux/compiler-gcc.h
+header-test- += linux/mutex_rt.h
 header-test- += linux/patchkey.h
 header-test- += linux/rwlock_api_smp.h
+header-test- += linux/rwlock_rt.h
+header-test- += linux/rwlock_types_rt.h
+header-test- += linux/rwsem-rt.h
+header-test- += linux/spinlock_rt.h
+header-test- += linux/spinlock_types_nort.h
+header-test- += linux/spinlock_types_rt.h
 header-test- += linux/spinlock_types_up.h
 header-test- += linux/spinlock_up.h
 header-test- += linux/wimax/debug.h
Index: linux-5.4.5-rt3/include/linux/bottom_half.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/bottom_half.h
+++ linux-5.4.5-rt3/include/linux/bottom_half.h
@@ -4,6 +4,10 @@
 
 #include <linux/preempt.h>
 
+#ifdef CONFIG_PREEMPT_RT
+extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
+#else
+
 #ifdef CONFIG_TRACE_IRQFLAGS
 extern void __local_bh_disable_ip(unsigned long ip, unsigned int cnt);
 #else
@@ -13,6 +17,7 @@ static __always_inline void __local_bh_d
 	barrier();
 }
 #endif
+#endif
 
 static inline void local_bh_disable(void)
 {
Index: linux-5.4.5-rt3/include/linux/buffer_head.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/buffer_head.h
+++ linux-5.4.5-rt3/include/linux/buffer_head.h
@@ -22,9 +22,6 @@ enum bh_state_bits {
 	BH_Dirty,	/* Is dirty */
 	BH_Lock,	/* Is locked */
 	BH_Req,		/* Has been submitted for I/O */
-	BH_Uptodate_Lock,/* Used by the first bh in a page, to serialise
-			  * IO completion of other buffers in the page
-			  */
 
 	BH_Mapped,	/* Has a disk mapping */
 	BH_New,		/* Disk mapping was newly created by get_block */
@@ -76,6 +73,9 @@ struct buffer_head {
 	struct address_space *b_assoc_map;	/* mapping this buffer is
 						   associated with */
 	atomic_t b_count;		/* users using this buffer_head */
+	spinlock_t b_uptodate_lock;	/* Used by the first bh in a page, to
+					 * serialise IO completion of other
+					 * buffers in the page */
 };
 
 /*
Index: linux-5.4.5-rt3/include/linux/cgroup-defs.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/cgroup-defs.h
+++ linux-5.4.5-rt3/include/linux/cgroup-defs.h
@@ -144,9 +144,6 @@ struct cgroup_subsys_state {
 	struct list_head sibling;
 	struct list_head children;
 
-	/* flush target list anchored at cgrp->rstat_css_list */
-	struct list_head rstat_css_node;
-
 	/*
 	 * PI: Subsys-unique ID.  0 is unused and root is always 1.  The
 	 * matching css can be looked up using css_from_id().
@@ -455,7 +452,6 @@ struct cgroup {
 
 	/* per-cpu recursive resource statistics */
 	struct cgroup_rstat_cpu __percpu *rstat_cpu;
-	struct list_head rstat_css_list;
 
 	/* cgroup basic resource statistics */
 	struct cgroup_base_stat pending_bstat;	/* pending from children */
@@ -633,7 +629,6 @@ struct cgroup_subsys {
 	void (*css_released)(struct cgroup_subsys_state *css);
 	void (*css_free)(struct cgroup_subsys_state *css);
 	void (*css_reset)(struct cgroup_subsys_state *css);
-	void (*css_rstat_flush)(struct cgroup_subsys_state *css, int cpu);
 	int (*css_extra_stat_show)(struct seq_file *seq,
 				   struct cgroup_subsys_state *css);
 
Index: linux-5.4.5-rt3/include/linux/cgroup.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/cgroup.h
+++ linux-5.4.5-rt3/include/linux/cgroup.h
@@ -750,9 +750,6 @@ static inline void cgroup_path_from_kern
  */
 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
 void cgroup_rstat_flush(struct cgroup *cgrp);
-void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp);
-void cgroup_rstat_flush_hold(struct cgroup *cgrp);
-void cgroup_rstat_flush_release(void);
 
 /*
  * Basic resource stats.
Index: linux-5.4.5-rt3/include/linux/completion.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/completion.h
+++ linux-5.4.5-rt3/include/linux/completion.h
@@ -9,7 +9,7 @@
  * See kernel/sched/completion.c for details.
  */
 
-#include <linux/wait.h>
+#include <linux/swait.h>
 
 /*
  * struct completion - structure used to maintain state for a "completion"
@@ -25,7 +25,7 @@
  */
 struct completion {
 	unsigned int done;
-	wait_queue_head_t wait;
+	struct swait_queue_head wait;
 };
 
 #define init_completion_map(x, m) __init_completion(x)
@@ -34,7 +34,7 @@ static inline void complete_acquire(stru
 static inline void complete_release(struct completion *x) {}
 
 #define COMPLETION_INITIALIZER(work) \
-	{ 0, __WAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
+	{ 0, __SWAIT_QUEUE_HEAD_INITIALIZER((work).wait) }
 
 #define COMPLETION_INITIALIZER_ONSTACK_MAP(work, map) \
 	(*({ init_completion_map(&(work), &(map)); &(work); }))
@@ -85,7 +85,7 @@ static inline void complete_release(stru
 static inline void __init_completion(struct completion *x)
 {
 	x->done = 0;
-	init_waitqueue_head(&x->wait);
+	init_swait_queue_head(&x->wait);
 }
 
 /**
Index: linux-5.4.5-rt3/include/linux/console.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/console.h
+++ linux-5.4.5-rt3/include/linux/console.h
@@ -145,6 +145,7 @@ static inline int con_debug_leave(void)
 struct console {
 	char	name[16];
 	void	(*write)(struct console *, const char *, unsigned);
+	void	(*write_atomic)(struct console *, const char *, unsigned);
 	int	(*read)(struct console *, char *, unsigned);
 	struct tty_driver *(*device)(struct console *, int *);
 	void	(*unblank)(void);
@@ -153,6 +154,8 @@ struct console {
 	short	flags;
 	short	index;
 	int	cflag;
+	unsigned long printk_seq;
+	int	wrote_history;
 	void	*data;
 	struct	 console *next;
 };
@@ -234,4 +237,7 @@ extern void console_init(void);
 void dummycon_register_output_notifier(struct notifier_block *nb);
 void dummycon_unregister_output_notifier(struct notifier_block *nb);
 
+extern void console_atomic_lock(unsigned int *flags);
+extern void console_atomic_unlock(unsigned int flags);
+
 #endif /* _LINUX_CONSOLE_H */
Index: linux-5.4.5-rt3/include/linux/dcache.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/dcache.h
+++ linux-5.4.5-rt3/include/linux/dcache.h
@@ -106,7 +106,7 @@ struct dentry {
 
 	union {
 		struct list_head d_lru;		/* LRU list */
-		wait_queue_head_t *d_wait;	/* in-lookup ones only */
+		struct swait_queue_head *d_wait;	/* in-lookup ones only */
 	};
 	struct list_head d_child;	/* child of parent list */
 	struct list_head d_subdirs;	/* our children */
@@ -236,7 +236,7 @@ extern void d_set_d_op(struct dentry *de
 extern struct dentry * d_alloc(struct dentry *, const struct qstr *);
 extern struct dentry * d_alloc_anon(struct super_block *);
 extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *,
-					wait_queue_head_t *);
+					struct swait_queue_head *);
 extern struct dentry * d_splice_alias(struct inode *, struct dentry *);
 extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *);
 extern struct dentry * d_exact_alias(struct dentry *, struct inode *);
Index: linux-5.4.5-rt3/include/linux/delay.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/delay.h
+++ linux-5.4.5-rt3/include/linux/delay.h
@@ -65,4 +65,10 @@ static inline void ssleep(unsigned int s
 	msleep(seconds * 1000);
 }
 
+#ifdef CONFIG_PREEMPT_RT
+extern void cpu_chill(void);
+#else
+# define cpu_chill()	cpu_relax()
+#endif
+
 #endif /* defined(_LINUX_DELAY_H) */
Index: linux-5.4.5-rt3/include/linux/dma-resv.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/dma-resv.h
+++ linux-5.4.5-rt3/include/linux/dma-resv.h
@@ -65,13 +65,13 @@ struct dma_resv_list {
 /**
  * struct dma_resv - a reservation object manages fences for a buffer
  * @lock: update side lock
- * @seq: sequence count for managing RCU read-side synchronization
+ * @seq: sequence lock for managing RCU read-side synchronization
  * @fence_excl: the exclusive fence, if there is one currently
  * @fence: list of current shared fences
  */
 struct dma_resv {
 	struct ww_mutex lock;
-	seqcount_t seq;
+	seqlock_t seq;
 
 	struct dma_fence __rcu *fence_excl;
 	struct dma_resv_list __rcu *fence;
Index: linux-5.4.5-rt3/include/linux/fs.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/fs.h
+++ linux-5.4.5-rt3/include/linux/fs.h
@@ -716,7 +716,7 @@ struct inode {
 		struct block_device	*i_bdev;
 		struct cdev		*i_cdev;
 		char			*i_link;
-		unsigned		i_dir_seq;
+		unsigned		__i_dir_seq;
 	};
 
 	__u32			i_generation;
@@ -855,7 +855,7 @@ static inline loff_t i_size_read(const s
 		i_size = inode->i_size;
 	} while (read_seqcount_retry(&inode->i_size_seqcount, seq));
 	return i_size;
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	loff_t i_size;
 
 	preempt_disable();
@@ -880,7 +880,7 @@ static inline void i_size_write(struct i
 	inode->i_size = i_size;
 	write_seqcount_end(&inode->i_size_seqcount);
 	preempt_enable();
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	preempt_disable();
 	inode->i_size = i_size;
 	preempt_enable();
Index: linux-5.4.5-rt3/include/linux/fscache.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/fscache.h
+++ linux-5.4.5-rt3/include/linux/fscache.h
@@ -226,6 +226,7 @@ extern void __fscache_readpages_cancel(s
 extern void __fscache_disable_cookie(struct fscache_cookie *, const void *, bool);
 extern void __fscache_enable_cookie(struct fscache_cookie *, const void *, loff_t,
 				    bool (*)(void *), void *);
+extern void fscache_cookie_init(void);
 
 /**
  * fscache_register_netfs - Register a filesystem as desiring caching services
Index: linux-5.4.5-rt3/include/linux/genhd.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/genhd.h
+++ linux-5.4.5-rt3/include/linux/genhd.h
@@ -717,7 +717,7 @@ static inline void hd_free_part(struct h
  * accessor function.
  *
  * Code written along the lines of i_size_read() and i_size_write().
- * CONFIG_PREEMPT case optimizes the case of UP kernel with preemption
+ * CONFIG_PREEMPTION case optimizes the case of UP kernel with preemption
  * on.
  */
 static inline sector_t part_nr_sects_read(struct hd_struct *part)
@@ -730,7 +730,7 @@ static inline sector_t part_nr_sects_rea
 		nr_sects = part->nr_sects;
 	} while (read_seqcount_retry(&part->nr_sects_seq, seq));
 	return nr_sects;
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	sector_t nr_sects;
 
 	preempt_disable();
@@ -753,7 +753,7 @@ static inline void part_nr_sects_write(s
 	write_seqcount_begin(&part->nr_sects_seq);
 	part->nr_sects = size;
 	write_seqcount_end(&part->nr_sects_seq);
-#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPT)
+#elif BITS_PER_LONG==32 && defined(CONFIG_PREEMPTION)
 	preempt_disable();
 	part->nr_sects = size;
 	preempt_enable();
Index: linux-5.4.5-rt3/include/linux/gfp.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/gfp.h
+++ linux-5.4.5-rt3/include/linux/gfp.h
@@ -580,6 +580,7 @@ extern void page_frag_free(void *addr);
 void page_alloc_init(void);
 void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
 void drain_all_pages(struct zone *zone);
+void drain_cpu_pages(unsigned int cpu, struct zone *zone);
 void drain_local_pages(struct zone *zone);
 
 void page_alloc_init_late(void);
Index: linux-5.4.5-rt3/include/linux/hardirq.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/hardirq.h
+++ linux-5.4.5-rt3/include/linux/hardirq.h
@@ -68,7 +68,6 @@ extern void irq_exit(void);
 #define nmi_enter()						\
 	do {							\
 		arch_nmi_enter();				\
-		printk_nmi_enter();				\
 		lockdep_off();					\
 		ftrace_nmi_enter();				\
 		BUG_ON(in_nmi());				\
@@ -85,7 +84,6 @@ extern void irq_exit(void);
 		preempt_count_sub(NMI_OFFSET + HARDIRQ_OFFSET);	\
 		ftrace_nmi_exit();				\
 		lockdep_on();					\
-		printk_nmi_exit();				\
 		arch_nmi_exit();				\
 	} while (0)
 
Index: linux-5.4.5-rt3/include/linux/highmem.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/highmem.h
+++ linux-5.4.5-rt3/include/linux/highmem.h
@@ -8,6 +8,7 @@
 #include <linux/mm.h>
 #include <linux/uaccess.h>
 #include <linux/hardirq.h>
+#include <linux/sched.h>
 
 #include <asm/cacheflush.h>
 
@@ -90,7 +91,7 @@ static inline void kunmap(struct page *p
 
 static inline void *kmap_atomic(struct page *page)
 {
-	preempt_disable();
+	preempt_disable_nort();
 	pagefault_disable();
 	return page_address(page);
 }
@@ -99,7 +100,7 @@ static inline void *kmap_atomic(struct p
 static inline void __kunmap_atomic(void *addr)
 {
 	pagefault_enable();
-	preempt_enable();
+	preempt_enable_nort();
 }
 
 #define kmap_atomic_pfn(pfn)	kmap_atomic(pfn_to_page(pfn))
@@ -111,32 +112,51 @@ static inline void __kunmap_atomic(void
 
 #if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
 
+#ifndef CONFIG_PREEMPT_RT
 DECLARE_PER_CPU(int, __kmap_atomic_idx);
+#endif
 
 static inline int kmap_atomic_idx_push(void)
 {
+#ifndef CONFIG_PREEMPT_RT
 	int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
 
-#ifdef CONFIG_DEBUG_HIGHMEM
+# ifdef CONFIG_DEBUG_HIGHMEM
 	WARN_ON_ONCE(in_irq() && !irqs_disabled());
 	BUG_ON(idx >= KM_TYPE_NR);
-#endif
+# endif
 	return idx;
+#else
+	current->kmap_idx++;
+	BUG_ON(current->kmap_idx > KM_TYPE_NR);
+	return current->kmap_idx - 1;
+#endif
 }
 
 static inline int kmap_atomic_idx(void)
 {
+#ifndef CONFIG_PREEMPT_RT
 	return __this_cpu_read(__kmap_atomic_idx) - 1;
+#else
+	return current->kmap_idx - 1;
+#endif
 }
 
 static inline void kmap_atomic_idx_pop(void)
 {
-#ifdef CONFIG_DEBUG_HIGHMEM
+#ifndef CONFIG_PREEMPT_RT
+# ifdef CONFIG_DEBUG_HIGHMEM
 	int idx = __this_cpu_dec_return(__kmap_atomic_idx);
 
 	BUG_ON(idx < 0);
-#else
+# else
 	__this_cpu_dec(__kmap_atomic_idx);
+# endif
+#else
+	current->kmap_idx--;
+# ifdef CONFIG_DEBUG_HIGHMEM
+	BUG_ON(current->kmap_idx < 0);
+# endif
 #endif
 }
 
Index: linux-5.4.5-rt3/include/linux/idr.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/idr.h
+++ linux-5.4.5-rt3/include/linux/idr.h
@@ -169,10 +169,7 @@ static inline bool idr_is_empty(const st
  * Each idr_preload() should be matched with an invocation of this
  * function.  See idr_preload() for details.
  */
-static inline void idr_preload_end(void)
-{
-	preempt_enable();
-}
+void idr_preload_end(void);
 
 /**
  * idr_for_each_entry() - Iterate over an IDR's elements of a given type.
Index: linux-5.4.5-rt3/include/linux/interrupt.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/interrupt.h
+++ linux-5.4.5-rt3/include/linux/interrupt.h
@@ -546,7 +546,7 @@ struct softirq_action
 asmlinkage void do_softirq(void);
 asmlinkage void __do_softirq(void);
 
-#ifdef __ARCH_HAS_DO_SOFTIRQ
+#if defined(__ARCH_HAS_DO_SOFTIRQ) && !defined(CONFIG_PREEMPT_RT)
 void do_softirq_own_stack(void);
 #else
 static inline void do_softirq_own_stack(void)
@@ -561,6 +561,7 @@ extern void __raise_softirq_irqoff(unsig
 
 extern void raise_softirq_irqoff(unsigned int nr);
 extern void raise_softirq(unsigned int nr);
+extern void softirq_check_pending_idle(void);
 
 DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
 
@@ -625,7 +626,10 @@ static inline void tasklet_unlock(struct
 
 static inline void tasklet_unlock_wait(struct tasklet_struct *t)
 {
-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
+	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
+		local_bh_disable();
+		local_bh_enable();
+	}
 }
 #else
 #define tasklet_trylock(t) 1
Index: linux-5.4.5-rt3/include/linux/irq_work.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/irq_work.h
+++ linux-5.4.5-rt3/include/linux/irq_work.h
@@ -18,6 +18,8 @@
 
 /* Doesn't want IPI, wait for tick: */
 #define IRQ_WORK_LAZY		BIT(2)
+/* Run hard IRQ context, even on RT */
+#define IRQ_WORK_HARD_IRQ	BIT(3)
 
 #define IRQ_WORK_CLAIMED	(IRQ_WORK_PENDING | IRQ_WORK_BUSY)
 
@@ -52,4 +54,10 @@ static inline bool irq_work_needs_cpu(vo
 static inline void irq_work_run(void) { }
 #endif
 
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
+void irq_work_tick_soft(void);
+#else
+static inline void irq_work_tick_soft(void) { }
+#endif
+
 #endif /* _LINUX_IRQ_WORK_H */
Index: linux-5.4.5-rt3/include/linux/irqdesc.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/irqdesc.h
+++ linux-5.4.5-rt3/include/linux/irqdesc.h
@@ -72,6 +72,7 @@ struct irq_desc {
 	unsigned int		irqs_unhandled;
 	atomic_t		threads_handled;
 	int			threads_handled_last;
+	u64			random_ip;
 	raw_spinlock_t		lock;
 	struct cpumask		*percpu_enabled;
 	const struct cpumask	*percpu_affinity;
Index: linux-5.4.5-rt3/include/linux/irqflags.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/irqflags.h
+++ linux-5.4.5-rt3/include/linux/irqflags.h
@@ -43,14 +43,6 @@ do {						\
 do {						\
 	current->hardirq_context--;		\
 } while (0)
-# define lockdep_softirq_enter()		\
-do {						\
-	current->softirq_context++;		\
-} while (0)
-# define lockdep_softirq_exit()			\
-do {						\
-	current->softirq_context--;		\
-} while (0)
 #else
 # define trace_hardirqs_on()		do { } while (0)
 # define trace_hardirqs_off()		do { } while (0)
@@ -63,6 +55,21 @@ do {						\
 # define lockdep_softirq_enter()	do { } while (0)
 # define lockdep_softirq_exit()		do { } while (0)
 #endif
+
+#if defined(CONFIG_TRACE_IRQFLAGS) && !defined(CONFIG_PREEMPT_RT)
+# define lockdep_softirq_enter()		\
+do {						\
+	current->softirq_context++;		\
+} while (0)
+# define lockdep_softirq_exit()			\
+do {						\
+	current->softirq_context--;		\
+} while (0)
+
+#else
+# define lockdep_softirq_enter()	do { } while (0)
+# define lockdep_softirq_exit()		do { } while (0)
+#endif
 
 #if defined(CONFIG_IRQSOFF_TRACER) || \
 	defined(CONFIG_PREEMPT_TRACER)
Index: linux-5.4.5-rt3/include/linux/jbd2.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/jbd2.h
+++ linux-5.4.5-rt3/include/linux/jbd2.h
@@ -313,7 +313,6 @@ enum jbd_state_bits {
 	BH_Revoked,		/* Has been revoked from the log */
 	BH_RevokeValid,		/* Revoked flag is valid */
 	BH_JBDDirty,		/* Is dirty but journaled */
-	BH_State,		/* Pins most journal_head state */
 	BH_JournalHead,		/* Pins bh->b_private and jh->b_bh */
 	BH_Shadow,		/* IO on shadow buffer is running */
 	BH_Verified,		/* Metadata block has been verified ok */
@@ -342,26 +341,6 @@ static inline struct journal_head *bh2jh
 	return bh->b_private;
 }
 
-static inline void jbd_lock_bh_state(struct buffer_head *bh)
-{
-	bit_spin_lock(BH_State, &bh->b_state);
-}
-
-static inline int jbd_trylock_bh_state(struct buffer_head *bh)
-{
-	return bit_spin_trylock(BH_State, &bh->b_state);
-}
-
-static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
-{
-	return bit_spin_is_locked(BH_State, &bh->b_state);
-}
-
-static inline void jbd_unlock_bh_state(struct buffer_head *bh)
-{
-	bit_spin_unlock(BH_State, &bh->b_state);
-}
-
 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
 {
 	bit_spin_lock(BH_JournalHead, &bh->b_state);
@@ -556,9 +535,9 @@ struct transaction_chp_stats_s {
  *      ->jbd_lock_bh_journal_head()	(This is "innermost")
  *
  *    j_state_lock
- *    ->jbd_lock_bh_state()
+ *    ->b_state_lock
  *
- *    jbd_lock_bh_state()
+ *    b_state_lock
  *    ->j_list_lock
  *
  *    j_state_lock
@@ -1257,7 +1236,7 @@ JBD2_FEATURE_INCOMPAT_FUNCS(csum3,		CSUM
 
 /* Filing buffers */
 extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *);
-extern void __jbd2_journal_refile_buffer(struct journal_head *);
+extern bool __jbd2_journal_refile_buffer(struct journal_head *);
 extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *);
 extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
 extern void __journal_free_buffer(struct journal_head *bh);
Index: linux-5.4.5-rt3/include/linux/journal-head.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/journal-head.h
+++ linux-5.4.5-rt3/include/linux/journal-head.h
@@ -11,6 +11,8 @@
 #ifndef JOURNAL_HEAD_H_INCLUDED
 #define JOURNAL_HEAD_H_INCLUDED
 
+#include <linux/spinlock.h>
+
 typedef unsigned int		tid_t;		/* Unique transaction ID */
 typedef struct transaction_s	transaction_t;	/* Compound transaction type */
 
@@ -24,13 +26,18 @@ struct journal_head {
 	struct buffer_head *b_bh;
 
 	/*
+	 * Protect the buffer head state
+	 */
+	spinlock_t b_state_lock;
+
+	/*
 	 * Reference count - see description in journal.c
 	 * [jbd_lock_bh_journal_head()]
 	 */
 	int b_jcount;
 
 	/*
-	 * Journalling list for this buffer [jbd_lock_bh_state()]
+	 * Journalling list for this buffer [b_state_lock]
 	 * NOTE: We *cannot* combine this with b_modified into a bitfield
 	 * as gcc would then (which the C standard allows but which is
 	 * very unuseful) make 64-bit accesses to the bitfield and clobber
@@ -41,20 +48,20 @@ struct journal_head {
 	/*
 	 * This flag signals the buffer has been modified by
 	 * the currently running transaction
-	 * [jbd_lock_bh_state()]
+	 * [b_state_lock]
 	 */
 	unsigned b_modified;
 
 	/*
 	 * Copy of the buffer data frozen for writing to the log.
-	 * [jbd_lock_bh_state()]
+	 * [b_state_lock]
 	 */
 	char *b_frozen_data;
 
 	/*
 	 * Pointer to a saved copy of the buffer containing no uncommitted
 	 * deallocation references, so that allocations can avoid overwriting
-	 * uncommitted deletes. [jbd_lock_bh_state()]
+	 * uncommitted deletes. [b_state_lock]
 	 */
 	char *b_committed_data;
 
@@ -63,7 +70,7 @@ struct journal_head {
 	 * metadata: either the running transaction or the committing
 	 * transaction (if there is one).  Only applies to buffers on a
 	 * transaction's data or metadata journaling list.
-	 * [j_list_lock] [jbd_lock_bh_state()]
+	 * [j_list_lock] [b_state_lock]
 	 * Either of these locks is enough for reading, both are needed for
 	 * changes.
 	 */
@@ -73,13 +80,13 @@ struct journal_head {
 	 * Pointer to the running compound transaction which is currently
 	 * modifying the buffer's metadata, if there was already a transaction
 	 * committing it when the new transaction touched it.
-	 * [t_list_lock] [jbd_lock_bh_state()]
+	 * [t_list_lock] [b_state_lock]
 	 */
 	transaction_t *b_next_transaction;
 
 	/*
 	 * Doubly-linked list of buffers on a transaction's data, metadata or
-	 * forget queue. [t_list_lock] [jbd_lock_bh_state()]
+	 * forget queue. [t_list_lock] [b_state_lock]
 	 */
 	struct journal_head *b_tnext, *b_tprev;
 
Index: linux-5.4.5-rt3/include/linux/kernel.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/kernel.h
+++ linux-5.4.5-rt3/include/linux/kernel.h
@@ -227,6 +227,10 @@ extern void __cant_sleep(const char *fil
  */
 # define might_sleep() \
 	do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+
+# define might_sleep_no_state_check() \
+	do { ___might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
+
 /**
  * cant_sleep - annotation for functions that cannot sleep
  *
@@ -258,6 +262,7 @@ extern void __cant_sleep(const char *fil
   static inline void __might_sleep(const char *file, int line,
 				   int preempt_offset) { }
 # define might_sleep() do { might_resched(); } while (0)
+# define might_sleep_no_state_check() do { might_resched(); } while (0)
 # define cant_sleep() do { } while (0)
 # define sched_annotate_sleep() do { } while (0)
 # define non_block_start() do { } while (0)
Index: linux-5.4.5-rt3/include/linux/kmsg_dump.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/kmsg_dump.h
+++ linux-5.4.5-rt3/include/linux/kmsg_dump.h
@@ -46,10 +46,8 @@ struct kmsg_dumper {
 	bool registered;
 
 	/* private state of the kmsg iterator */
-	u32 cur_idx;
-	u32 next_idx;
-	u64 cur_seq;
-	u64 next_seq;
+	u64 line_seq;
+	u64 buffer_end_seq;
 };
 
 #ifdef CONFIG_PRINTK
Index: linux-5.4.5-rt3/include/linux/list_bl.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/list_bl.h
+++ linux-5.4.5-rt3/include/linux/list_bl.h
@@ -3,6 +3,7 @@
 #define _LINUX_LIST_BL_H
 
 #include <linux/list.h>
+#include <linux/spinlock.h>
 #include <linux/bit_spinlock.h>
 
 /*
@@ -33,13 +34,24 @@
 
 struct hlist_bl_head {
 	struct hlist_bl_node *first;
+#ifdef CONFIG_PREEMPT_RT
+	raw_spinlock_t lock;
+#endif
 };
 
 struct hlist_bl_node {
 	struct hlist_bl_node *next, **pprev;
 };
-#define INIT_HLIST_BL_HEAD(ptr) \
-	((ptr)->first = NULL)
+
+#ifdef CONFIG_PREEMPT_RT
+#define INIT_HLIST_BL_HEAD(h)		\
+do {					\
+	(h)->first = NULL;		\
+	raw_spin_lock_init(&(h)->lock);	\
+} while (0)
+#else
+#define INIT_HLIST_BL_HEAD(h) (h)->first = NULL
+#endif
 
 static inline void INIT_HLIST_BL_NODE(struct hlist_bl_node *h)
 {
@@ -145,12 +157,26 @@ static inline void hlist_bl_del_init(str
 
 static inline void hlist_bl_lock(struct hlist_bl_head *b)
 {
+#ifndef CONFIG_PREEMPT_RT
 	bit_spin_lock(0, (unsigned long *)b);
+#else
+	raw_spin_lock(&b->lock);
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+	__set_bit(0, (unsigned long *)b);
+#endif
+#endif
 }
 
 static inline void hlist_bl_unlock(struct hlist_bl_head *b)
 {
+#ifndef CONFIG_PREEMPT_RT
 	__bit_spin_unlock(0, (unsigned long *)b);
+#else
+#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
+	__clear_bit(0, (unsigned long *)b);
+#endif
+	raw_spin_unlock(&b->lock);
+#endif
 }
 
 static inline bool hlist_bl_is_locked(struct hlist_bl_head *b)
Index: linux-5.4.5-rt3/include/linux/locallock.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/locallock.h
@@ -0,0 +1,282 @@
+#ifndef _LINUX_LOCALLOCK_H
+#define _LINUX_LOCALLOCK_H
+
+#include <linux/percpu.h>
+#include <linux/spinlock.h>
+#include <asm/current.h>
+
+#ifdef CONFIG_PREEMPT_RT
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+# define LL_WARN(cond)	WARN_ON(cond)
+#else
+# define LL_WARN(cond)	do { } while (0)
+#endif
+
+/*
+ * per cpu lock based substitute for local_irq_*()
+ */
+struct local_irq_lock {
+	spinlock_t		lock;
+	struct task_struct	*owner;
+	int			nestcnt;
+	unsigned long		flags;
+};
+
+#define DEFINE_LOCAL_IRQ_LOCK(lvar)					\
+	DEFINE_PER_CPU(struct local_irq_lock, lvar) = {			\
+		.lock = __SPIN_LOCK_UNLOCKED((lvar).lock) }
+
+#define DECLARE_LOCAL_IRQ_LOCK(lvar)					\
+	DECLARE_PER_CPU(struct local_irq_lock, lvar)
+
+#define local_irq_lock_init(lvar)					\
+	do {								\
+		int __cpu;						\
+		for_each_possible_cpu(__cpu)				\
+			spin_lock_init(&per_cpu(lvar, __cpu).lock);	\
+	} while (0)
+
+static inline void __local_lock(struct local_irq_lock *lv)
+{
+	if (lv->owner != current) {
+		spin_lock(&lv->lock);
+		LL_WARN(lv->owner);
+		LL_WARN(lv->nestcnt);
+		lv->owner = current;
+	}
+	lv->nestcnt++;
+}
+
+#define local_lock(lvar)					\
+	do { __local_lock(&get_local_var(lvar)); } while (0)
+
+#define local_lock_on(lvar, cpu)				\
+	do { __local_lock(&per_cpu(lvar, cpu)); } while (0)
+
+static inline int __local_trylock(struct local_irq_lock *lv)
+{
+	if (lv->owner != current && spin_trylock(&lv->lock)) {
+		LL_WARN(lv->owner);
+		LL_WARN(lv->nestcnt);
+		lv->owner = current;
+		lv->nestcnt = 1;
+		return 1;
+	} else if (lv->owner == current) {
+		lv->nestcnt++;
+		return 1;
+	}
+	return 0;
+}
+
+#define local_trylock(lvar)						\
+	({								\
+		int __locked;						\
+		__locked = __local_trylock(&get_local_var(lvar));	\
+		if (!__locked)						\
+			put_local_var(lvar);				\
+		__locked;						\
+	})
+
+static inline void __local_unlock(struct local_irq_lock *lv)
+{
+	LL_WARN(lv->nestcnt == 0);
+	LL_WARN(lv->owner != current);
+	if (--lv->nestcnt)
+		return;
+
+	lv->owner = NULL;
+	spin_unlock(&lv->lock);
+}
+
+#define local_unlock(lvar)					\
+	do {							\
+		__local_unlock(this_cpu_ptr(&lvar));		\
+		put_local_var(lvar);				\
+	} while (0)
+
+#define local_unlock_on(lvar, cpu)                       \
+	do { __local_unlock(&per_cpu(lvar, cpu)); } while (0)
+
+static inline void __local_lock_irq(struct local_irq_lock *lv)
+{
+	spin_lock_irqsave(&lv->lock, lv->flags);
+	LL_WARN(lv->owner);
+	LL_WARN(lv->nestcnt);
+	lv->owner = current;
+	lv->nestcnt = 1;
+}
+
+#define local_lock_irq(lvar)						\
+	do { __local_lock_irq(&get_local_var(lvar)); } while (0)
+
+#define local_lock_irq_on(lvar, cpu)					\
+	do { __local_lock_irq(&per_cpu(lvar, cpu)); } while (0)
+
+static inline void __local_unlock_irq(struct local_irq_lock *lv)
+{
+	LL_WARN(!lv->nestcnt);
+	LL_WARN(lv->owner != current);
+	lv->owner = NULL;
+	lv->nestcnt = 0;
+	spin_unlock_irq(&lv->lock);
+}
+
+#define local_unlock_irq(lvar)						\
+	do {								\
+		__local_unlock_irq(this_cpu_ptr(&lvar));		\
+		put_local_var(lvar);					\
+	} while (0)
+
+#define local_unlock_irq_on(lvar, cpu)					\
+	do {								\
+		__local_unlock_irq(&per_cpu(lvar, cpu));		\
+	} while (0)
+
+static inline int __local_lock_irqsave(struct local_irq_lock *lv)
+{
+	if (lv->owner != current) {
+		__local_lock_irq(lv);
+		return 0;
+	} else {
+		lv->nestcnt++;
+		return 1;
+	}
+}
+
+#define local_lock_irqsave(lvar, _flags)				\
+	do {								\
+		if (__local_lock_irqsave(&get_local_var(lvar)))		\
+			put_local_var(lvar);				\
+		_flags = __this_cpu_read(lvar.flags);			\
+	} while (0)
+
+#define local_lock_irqsave_on(lvar, _flags, cpu)			\
+	do {								\
+		__local_lock_irqsave(&per_cpu(lvar, cpu));		\
+		_flags = per_cpu(lvar, cpu).flags;			\
+	} while (0)
+
+static inline int __local_unlock_irqrestore(struct local_irq_lock *lv,
+					    unsigned long flags)
+{
+	LL_WARN(!lv->nestcnt);
+	LL_WARN(lv->owner != current);
+	if (--lv->nestcnt)
+		return 0;
+
+	lv->owner = NULL;
+	spin_unlock_irqrestore(&lv->lock, lv->flags);
+	return 1;
+}
+
+#define local_unlock_irqrestore(lvar, flags)				\
+	do {								\
+		if (__local_unlock_irqrestore(this_cpu_ptr(&lvar), flags)) \
+			put_local_var(lvar);				\
+	} while (0)
+
+#define local_unlock_irqrestore_on(lvar, flags, cpu)			\
+	do {								\
+		__local_unlock_irqrestore(&per_cpu(lvar, cpu), flags);	\
+	} while (0)
+
+#define local_spin_trylock_irq(lvar, lock)				\
+	({								\
+		int __locked;						\
+		local_lock_irq(lvar);					\
+		__locked = spin_trylock(lock);				\
+		if (!__locked)						\
+			local_unlock_irq(lvar);				\
+		__locked;						\
+	})
+
+#define local_spin_lock_irq(lvar, lock)					\
+	do {								\
+		local_lock_irq(lvar);					\
+		spin_lock(lock);					\
+	} while (0)
+
+#define local_spin_unlock_irq(lvar, lock)				\
+	do {								\
+		spin_unlock(lock);					\
+		local_unlock_irq(lvar);					\
+	} while (0)
+
+#define local_spin_lock_irqsave(lvar, lock, flags)			\
+	do {								\
+		local_lock_irqsave(lvar, flags);			\
+		spin_lock(lock);					\
+	} while (0)
+
+#define local_spin_unlock_irqrestore(lvar, lock, flags)			\
+	do {								\
+		spin_unlock(lock);					\
+		local_unlock_irqrestore(lvar, flags);			\
+	} while (0)
+
+#define get_locked_var(lvar, var)					\
+	(*({								\
+		local_lock(lvar);					\
+		this_cpu_ptr(&var);					\
+	}))
+
+#define put_locked_var(lvar, var)	local_unlock(lvar);
+
+#define get_locked_ptr(lvar, var)					\
+	({								\
+		local_lock(lvar);					\
+		this_cpu_ptr(var);					\
+	})
+
+#define put_locked_ptr(lvar, var)	local_unlock(lvar);
+
+#define local_lock_cpu(lvar)						\
+	({								\
+		local_lock(lvar);					\
+		smp_processor_id();					\
+	})
+
+#define local_unlock_cpu(lvar)			local_unlock(lvar)
+
+#else /* PREEMPT_RT */
+
+#define DEFINE_LOCAL_IRQ_LOCK(lvar)		__typeof__(const int) lvar
+#define DECLARE_LOCAL_IRQ_LOCK(lvar)		extern __typeof__(const int) lvar
+
+static inline void local_irq_lock_init(int lvar) { }
+
+#define local_trylock(lvar)					\
+	({							\
+		preempt_disable();				\
+		1;						\
+	})
+
+#define local_lock(lvar)			preempt_disable()
+#define local_unlock(lvar)			preempt_enable()
+#define local_lock_irq(lvar)			local_irq_disable()
+#define local_lock_irq_on(lvar, cpu)		local_irq_disable()
+#define local_unlock_irq(lvar)			local_irq_enable()
+#define local_unlock_irq_on(lvar, cpu)		local_irq_enable()
+#define local_lock_irqsave(lvar, flags)		local_irq_save(flags)
+#define local_unlock_irqrestore(lvar, flags)	local_irq_restore(flags)
+
+#define local_spin_trylock_irq(lvar, lock)	spin_trylock_irq(lock)
+#define local_spin_lock_irq(lvar, lock)		spin_lock_irq(lock)
+#define local_spin_unlock_irq(lvar, lock)	spin_unlock_irq(lock)
+#define local_spin_lock_irqsave(lvar, lock, flags)	\
+	spin_lock_irqsave(lock, flags)
+#define local_spin_unlock_irqrestore(lvar, lock, flags)	\
+	spin_unlock_irqrestore(lock, flags)
+
+#define get_locked_var(lvar, var)		get_cpu_var(var)
+#define put_locked_var(lvar, var)		put_cpu_var(var)
+#define get_locked_ptr(lvar, var)		get_cpu_ptr(var)
+#define put_locked_ptr(lvar, var)		put_cpu_ptr(var)
+
+#define local_lock_cpu(lvar)			get_cpu()
+#define local_unlock_cpu(lvar)			put_cpu()
+
+#endif
+
+#endif
Index: linux-5.4.5-rt3/include/linux/mm_types.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/mm_types.h
+++ linux-5.4.5-rt3/include/linux/mm_types.h
@@ -12,6 +12,7 @@
 #include <linux/completion.h>
 #include <linux/cpumask.h>
 #include <linux/uprobes.h>
+#include <linux/rcupdate.h>
 #include <linux/page-flags-layout.h>
 #include <linux/workqueue.h>
 
@@ -520,6 +521,9 @@ struct mm_struct {
 		bool tlb_flush_batched;
 #endif
 		struct uprobes_state uprobes_state;
+#ifdef CONFIG_PREEMPT_RT
+		struct rcu_head delayed_drop;
+#endif
 #ifdef CONFIG_HUGETLB_PAGE
 		atomic_long_t hugetlb_usage;
 #endif
Index: linux-5.4.5-rt3/include/linux/mutex.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/mutex.h
+++ linux-5.4.5-rt3/include/linux/mutex.h
@@ -22,6 +22,17 @@
 
 struct ww_acquire_ctx;
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
+		, .dep_map = { .name = #lockname }
+#else
+# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
+#endif
+
+#ifdef CONFIG_PREEMPT_RT
+# include <linux/mutex_rt.h>
+#else
+
 /*
  * Simple, straightforward mutexes with strict semantics:
  *
@@ -108,13 +119,6 @@ do {									\
 	__mutex_init((mutex), #mutex, &__key);				\
 } while (0)
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname) \
-		, .dep_map = { .name = #lockname }
-#else
-# define __DEP_MAP_MUTEX_INITIALIZER(lockname)
-#endif
-
 #define __MUTEX_INITIALIZER(lockname) \
 		{ .owner = ATOMIC_LONG_INIT(0) \
 		, .wait_lock = __SPIN_LOCK_UNLOCKED(lockname.wait_lock) \
@@ -210,4 +214,6 @@ enum mutex_trylock_recursive_enum {
 extern /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
 mutex_trylock_recursive(struct mutex *lock);
 
+#endif /* !PREEMPT_RT */
+
 #endif /* __LINUX_MUTEX_H */
Index: linux-5.4.5-rt3/include/linux/mutex_rt.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/mutex_rt.h
@@ -0,0 +1,130 @@
+#ifndef __LINUX_MUTEX_RT_H
+#define __LINUX_MUTEX_RT_H
+
+#ifndef __LINUX_MUTEX_H
+#error "Please include mutex.h"
+#endif
+
+#include <linux/rtmutex.h>
+
+/* FIXME: Just for __lockfunc */
+#include <linux/spinlock.h>
+
+struct mutex {
+	struct rt_mutex		lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define __MUTEX_INITIALIZER(mutexname)					\
+	{								\
+		.lock = __RT_MUTEX_INITIALIZER(mutexname.lock)		\
+		__DEP_MAP_MUTEX_INITIALIZER(mutexname)			\
+	}
+
+#define DEFINE_MUTEX(mutexname)						\
+	struct mutex mutexname = __MUTEX_INITIALIZER(mutexname)
+
+extern void __mutex_do_init(struct mutex *lock, const char *name, struct lock_class_key *key);
+extern void __lockfunc _mutex_lock(struct mutex *lock);
+extern void __lockfunc _mutex_lock_io(struct mutex *lock);
+extern void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_lock_interruptible(struct mutex *lock);
+extern int __lockfunc _mutex_lock_killable(struct mutex *lock);
+extern void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass);
+extern void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest_lock);
+extern int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass);
+extern int __lockfunc _mutex_trylock(struct mutex *lock);
+extern void __lockfunc _mutex_unlock(struct mutex *lock);
+
+#define mutex_is_locked(l)		rt_mutex_is_locked(&(l)->lock)
+#define mutex_lock(l)			_mutex_lock(l)
+#define mutex_lock_interruptible(l)	_mutex_lock_interruptible(l)
+#define mutex_lock_killable(l)		_mutex_lock_killable(l)
+#define mutex_trylock(l)		_mutex_trylock(l)
+#define mutex_unlock(l)			_mutex_unlock(l)
+#define mutex_lock_io(l)		_mutex_lock_io(l);
+
+#define __mutex_owner(l)		((l)->lock.owner)
+
+#ifdef CONFIG_DEBUG_MUTEXES
+#define mutex_destroy(l)		rt_mutex_destroy(&(l)->lock)
+#else
+static inline void mutex_destroy(struct mutex *lock) {}
+#endif
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define mutex_lock_nested(l, s)	_mutex_lock_nested(l, s)
+# define mutex_lock_interruptible_nested(l, s) \
+					_mutex_lock_interruptible_nested(l, s)
+# define mutex_lock_killable_nested(l, s) \
+					_mutex_lock_killable_nested(l, s)
+# define mutex_lock_io_nested(l, s)	_mutex_lock_io_nested(l, s)
+
+# define mutex_lock_nest_lock(lock, nest_lock)				\
+do {									\
+	typecheck(struct lockdep_map *, &(nest_lock)->dep_map);		\
+	_mutex_lock_nest_lock(lock, &(nest_lock)->dep_map);		\
+} while (0)
+
+#else
+# define mutex_lock_nested(l, s)	_mutex_lock(l)
+# define mutex_lock_interruptible_nested(l, s) \
+					_mutex_lock_interruptible(l)
+# define mutex_lock_killable_nested(l, s) \
+					_mutex_lock_killable(l)
+# define mutex_lock_nest_lock(lock, nest_lock) mutex_lock(lock)
+# define mutex_lock_io_nested(l, s)	_mutex_lock_io(l)
+#endif
+
+# define mutex_init(mutex)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	rt_mutex_init(&(mutex)->lock);			\
+	__mutex_do_init((mutex), #mutex, &__key);	\
+} while (0)
+
+# define __mutex_init(mutex, name, key)			\
+do {							\
+	rt_mutex_init(&(mutex)->lock);			\
+	__mutex_do_init((mutex), name, key);		\
+} while (0)
+
+/**
+ * These values are chosen such that FAIL and SUCCESS match the
+ * values of the regular mutex_trylock().
+ */
+enum mutex_trylock_recursive_enum {
+	MUTEX_TRYLOCK_FAILED    = 0,
+	MUTEX_TRYLOCK_SUCCESS   = 1,
+	MUTEX_TRYLOCK_RECURSIVE,
+};
+/**
+ * mutex_trylock_recursive - trylock variant that allows recursive locking
+ * @lock: mutex to be locked
+ *
+ * This function should not be used, _ever_. It is purely for hysterical GEM
+ * raisins, and once those are gone this will be removed.
+ *
+ * Returns:
+ *  MUTEX_TRYLOCK_FAILED    - trylock failed,
+ *  MUTEX_TRYLOCK_SUCCESS   - lock acquired,
+ *  MUTEX_TRYLOCK_RECURSIVE - we already owned the lock.
+ */
+int __rt_mutex_owner_current(struct rt_mutex *lock);
+
+static inline /* __deprecated */ __must_check enum mutex_trylock_recursive_enum
+mutex_trylock_recursive(struct mutex *lock)
+{
+	if (unlikely(__rt_mutex_owner_current(&lock->lock)))
+		return MUTEX_TRYLOCK_RECURSIVE;
+
+	return mutex_trylock(lock);
+}
+
+extern int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock);
+
+#endif
Index: linux-5.4.5-rt3/include/linux/netdevice.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/netdevice.h
+++ linux-5.4.5-rt3/include/linux/netdevice.h
@@ -3016,6 +3016,7 @@ struct softnet_data {
 	unsigned int		dropped;
 	struct sk_buff_head	input_pkt_queue;
 	struct napi_struct	backlog;
+	struct sk_buff_head	tofree_queue;
 
 };
 
Index: linux-5.4.5-rt3/include/linux/nfs_fs.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/nfs_fs.h
+++ linux-5.4.5-rt3/include/linux/nfs_fs.h
@@ -165,7 +165,11 @@ struct nfs_inode {
 
 	/* Readers: in-flight sillydelete RPC calls */
 	/* Writers: rmdir */
+#ifdef CONFIG_PREEMPT_RT
+	struct semaphore        rmdir_sem;
+#else
 	struct rw_semaphore	rmdir_sem;
+#endif
 	struct mutex		commit_mutex;
 
 #if IS_ENABLED(CONFIG_NFS_V4)
Index: linux-5.4.5-rt3/include/linux/nfs_xdr.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/nfs_xdr.h
+++ linux-5.4.5-rt3/include/linux/nfs_xdr.h
@@ -1594,7 +1594,7 @@ struct nfs_unlinkdata {
 	struct nfs_removeargs args;
 	struct nfs_removeres res;
 	struct dentry *dentry;
-	wait_queue_head_t wq;
+	struct swait_queue_head wq;
 	const struct cred *cred;
 	struct nfs_fattr dir_attr;
 	long timeout;
Index: linux-5.4.5-rt3/include/linux/percpu-refcount.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/percpu-refcount.h
+++ linux-5.4.5-rt3/include/linux/percpu-refcount.h
@@ -186,14 +186,14 @@ static inline void percpu_ref_get_many(s
 {
 	unsigned long __percpu *percpu_count;
 
-	rcu_read_lock_sched();
+	rcu_read_lock();
 
 	if (__ref_is_percpu(ref, &percpu_count))
 		this_cpu_add(*percpu_count, nr);
 	else
 		atomic_long_add(nr, &ref->count);
 
-	rcu_read_unlock_sched();
+	rcu_read_unlock();
 }
 
 /**
@@ -223,7 +223,7 @@ static inline bool percpu_ref_tryget(str
 	unsigned long __percpu *percpu_count;
 	bool ret;
 
-	rcu_read_lock_sched();
+	rcu_read_lock();
 
 	if (__ref_is_percpu(ref, &percpu_count)) {
 		this_cpu_inc(*percpu_count);
@@ -232,7 +232,7 @@ static inline bool percpu_ref_tryget(str
 		ret = atomic_long_inc_not_zero(&ref->count);
 	}
 
-	rcu_read_unlock_sched();
+	rcu_read_unlock();
 
 	return ret;
 }
@@ -257,7 +257,7 @@ static inline bool percpu_ref_tryget_liv
 	unsigned long __percpu *percpu_count;
 	bool ret = false;
 
-	rcu_read_lock_sched();
+	rcu_read_lock();
 
 	if (__ref_is_percpu(ref, &percpu_count)) {
 		this_cpu_inc(*percpu_count);
@@ -266,7 +266,7 @@ static inline bool percpu_ref_tryget_liv
 		ret = atomic_long_inc_not_zero(&ref->count);
 	}
 
-	rcu_read_unlock_sched();
+	rcu_read_unlock();
 
 	return ret;
 }
@@ -285,14 +285,14 @@ static inline void percpu_ref_put_many(s
 {
 	unsigned long __percpu *percpu_count;
 
-	rcu_read_lock_sched();
+	rcu_read_lock();
 
 	if (__ref_is_percpu(ref, &percpu_count))
 		this_cpu_sub(*percpu_count, nr);
 	else if (unlikely(atomic_long_sub_and_test(nr, &ref->count)))
 		ref->release(ref);
 
-	rcu_read_unlock_sched();
+	rcu_read_unlock();
 }
 
 /**
Index: linux-5.4.5-rt3/include/linux/percpu-rwsem.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/percpu-rwsem.h
+++ linux-5.4.5-rt3/include/linux/percpu-rwsem.h
@@ -3,41 +3,52 @@
 #define _LINUX_PERCPU_RWSEM_H
 
 #include <linux/atomic.h>
-#include <linux/rwsem.h>
 #include <linux/percpu.h>
 #include <linux/rcuwait.h>
+#include <linux/wait.h>
 #include <linux/rcu_sync.h>
 #include <linux/lockdep.h>
 
 struct percpu_rw_semaphore {
 	struct rcu_sync		rss;
 	unsigned int __percpu	*read_count;
-	struct rw_semaphore	rw_sem; /* slowpath */
-	struct rcuwait          writer; /* blocked writer */
-	int			readers_block;
+	struct rcuwait		writer;
+	wait_queue_head_t	waiters;
+	atomic_t		block;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
 };
 
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname },
+#else
+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)
+#endif
+
 #define __DEFINE_PERCPU_RWSEM(name, is_static)				\
 static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name);		\
 is_static struct percpu_rw_semaphore name = {				\
 	.rss = __RCU_SYNC_INITIALIZER(name.rss),			\
 	.read_count = &__percpu_rwsem_rc_##name,			\
-	.rw_sem = __RWSEM_INITIALIZER(name.rw_sem),			\
 	.writer = __RCUWAIT_INITIALIZER(name.writer),			\
+	.waiters = __WAIT_QUEUE_HEAD_INITIALIZER(name.waiters),		\
+	.block = ATOMIC_INIT(0),					\
+	__PERCPU_RWSEM_DEP_MAP_INIT(name)				\
 }
+
 #define DEFINE_PERCPU_RWSEM(name)		\
 	__DEFINE_PERCPU_RWSEM(name, /* not static */)
 #define DEFINE_STATIC_PERCPU_RWSEM(name)	\
 	__DEFINE_PERCPU_RWSEM(name, static)
 
-extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
-extern void __percpu_up_read(struct percpu_rw_semaphore *);
+extern bool __percpu_down_read(struct percpu_rw_semaphore *, bool);
 
 static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
 {
 	might_sleep();
 
-	rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 0, _RET_IP_);
+	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
 
 	preempt_disable();
 	/*
@@ -48,8 +59,9 @@ static inline void percpu_down_read(stru
 	 * and that once the synchronize_rcu() is done, the writer will see
 	 * anything we did within this RCU-sched read-size critical section.
 	 */
-	__this_cpu_inc(*sem->read_count);
-	if (unlikely(!rcu_sync_is_idle(&sem->rss)))
+	if (likely(rcu_sync_is_idle(&sem->rss)))
+		__this_cpu_inc(*sem->read_count);
+	else
 		__percpu_down_read(sem, false); /* Unconditional memory barrier */
 	/*
 	 * The preempt_enable() prevents the compiler from
@@ -58,16 +70,17 @@ static inline void percpu_down_read(stru
 	preempt_enable();
 }
 
-static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
+static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
 {
-	int ret = 1;
+	bool ret = true;
 
 	preempt_disable();
 	/*
 	 * Same as in percpu_down_read().
 	 */
-	__this_cpu_inc(*sem->read_count);
-	if (unlikely(!rcu_sync_is_idle(&sem->rss)))
+	if (likely(rcu_sync_is_idle(&sem->rss)))
+		__this_cpu_inc(*sem->read_count);
+	else
 		ret = __percpu_down_read(sem, true); /* Unconditional memory barrier */
 	preempt_enable();
 	/*
@@ -76,24 +89,36 @@ static inline int percpu_down_read_trylo
 	 */
 
 	if (ret)
-		rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 1, _RET_IP_);
+		rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
 
 	return ret;
 }
 
 static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 {
+	rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
 	preempt_disable();
 	/*
 	 * Same as in percpu_down_read().
 	 */
-	if (likely(rcu_sync_is_idle(&sem->rss)))
+	if (likely(rcu_sync_is_idle(&sem->rss))) {
 		__this_cpu_dec(*sem->read_count);
-	else
-		__percpu_up_read(sem); /* Unconditional memory barrier */
+	} else {
+		/*
+		 * slowpath; reader will only ever wake a single blocked
+		 * writer.
+		 */
+		smp_mb(); /* B matches C */
+		/*
+		 * In other words, if they see our decrement (presumably to
+		 * aggregate zero, as that is the only time it matters) they
+		 * will also see our critical section.
+		 */
+		__this_cpu_dec(*sem->read_count);
+		rcuwait_wake_up(&sem->writer);
+	}
 	preempt_enable();
-
-	rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_);
 }
 
 extern void percpu_down_write(struct percpu_rw_semaphore *);
@@ -110,29 +135,19 @@ extern void percpu_free_rwsem(struct per
 	__percpu_init_rwsem(sem, #sem, &rwsem_key);		\
 })
 
-#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
-
-#define percpu_rwsem_assert_held(sem)				\
-	lockdep_assert_held(&(sem)->rw_sem)
+#define percpu_rwsem_is_held(sem) lockdep_is_held(sem)
+#define percpu_rwsem_assert_held(sem)  lockdep_assert_held(sem)
 
 static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
 					bool read, unsigned long ip)
 {
-	lock_release(&sem->rw_sem.dep_map, 1, ip);
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-	if (!read)
-		atomic_long_set(&sem->rw_sem.owner, RWSEM_OWNER_UNKNOWN);
-#endif
+	lock_release(&sem->dep_map, 1, ip);
 }
 
 static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
 					bool read, unsigned long ip)
 {
-	lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
-	if (!read)
-		atomic_long_set(&sem->rw_sem.owner, (long)current);
-#endif
+	lock_acquire(&sem->dep_map, 0, 1, read, 1, NULL, ip);
 }
 
 #endif
Index: linux-5.4.5-rt3/include/linux/percpu.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/percpu.h
+++ linux-5.4.5-rt3/include/linux/percpu.h
@@ -19,6 +19,35 @@
 #define PERCPU_MODULE_RESERVE		0
 #endif
 
+#ifdef CONFIG_PREEMPT_RT
+
+#define get_local_var(var) (*({	\
+	migrate_disable();	\
+	this_cpu_ptr(&var);	}))
+
+#define put_local_var(var) do {	\
+	(void)&(var);		\
+	migrate_enable();	\
+} while (0)
+
+# define get_local_ptr(var) ({	\
+	migrate_disable();	\
+	this_cpu_ptr(var);	})
+
+# define put_local_ptr(var) do {	\
+	(void)(var);			\
+	migrate_enable();		\
+} while (0)
+
+#else
+
+#define get_local_var(var)	get_cpu_var(var)
+#define put_local_var(var)	put_cpu_var(var)
+#define get_local_ptr(var)	get_cpu_ptr(var)
+#define put_local_ptr(var)	put_cpu_ptr(var)
+
+#endif
+
 /* minimum unit size, also is the maximum supported allocation size */
 #define PCPU_MIN_UNIT_SIZE		PFN_ALIGN(32 << 10)
 
Index: linux-5.4.5-rt3/include/linux/pid.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/pid.h
+++ linux-5.4.5-rt3/include/linux/pid.h
@@ -3,6 +3,7 @@
 #define _LINUX_PID_H
 
 #include <linux/rculist.h>
+#include <linux/atomic.h>
 #include <linux/wait.h>
 #include <linux/refcount.h>
 
Index: linux-5.4.5-rt3/include/linux/posix-timers.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/posix-timers.h
+++ linux-5.4.5-rt3/include/linux/posix-timers.h
@@ -72,6 +72,7 @@ struct cpu_timer {
 	struct task_struct	*task;
 	struct list_head	elist;
 	int			firing;
+	int			firing_cpu;
 };
 
 static inline bool cpu_timer_enqueue(struct timerqueue_head *head,
@@ -123,6 +124,9 @@ struct posix_cputimers {
 	struct posix_cputimer_base	bases[CPUCLOCK_MAX];
 	unsigned int			timers_active;
 	unsigned int			expiry_active;
+#ifdef CONFIG_PREEMPT_RT
+	struct task_struct		*posix_timer_list;
+#endif
 };
 
 static inline void posix_cputimers_init(struct posix_cputimers *pct)
@@ -152,9 +156,16 @@ static inline void posix_cputimers_rt_wa
 	INIT_CPU_TIMERBASE(b[2]),					\
 }
 
+#ifdef CONFIG_PREEMPT_RT
+# define INIT_TIMER_LIST	.posix_timer_list = NULL,
+#else
+# define INIT_TIMER_LIST
+#endif
+
 #define INIT_CPU_TIMERS(s)						\
 	.posix_cputimers = {						\
 		.bases = INIT_CPU_TIMERBASES(s.posix_cputimers.bases),	\
+		INIT_TIMER_LIST						\
 	},
 #else
 struct posix_cputimers { };
Index: linux-5.4.5-rt3/include/linux/preempt.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/preempt.h
+++ linux-5.4.5-rt3/include/linux/preempt.h
@@ -78,10 +78,8 @@
 #include <asm/preempt.h>
 
 #define hardirq_count()	(preempt_count() & HARDIRQ_MASK)
-#define softirq_count()	(preempt_count() & SOFTIRQ_MASK)
 #define irq_count()	(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_MASK \
 				 | NMI_MASK))
-
 /*
  * Are we doing bottom half or hardware interrupt processing?
  *
@@ -96,12 +94,23 @@
  *       should not be used in new code.
  */
 #define in_irq()		(hardirq_count())
-#define in_softirq()		(softirq_count())
 #define in_interrupt()		(irq_count())
-#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
 #define in_nmi()		(preempt_count() & NMI_MASK)
 #define in_task()		(!(preempt_count() & \
 				   (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))
+#ifdef CONFIG_PREEMPT_RT
+
+#define softirq_count()		((long)current->softirq_count)
+#define in_softirq()		(softirq_count())
+#define in_serving_softirq()	(current->softirq_count & SOFTIRQ_OFFSET)
+
+#else
+
+#define softirq_count()		(preempt_count() & SOFTIRQ_MASK)
+#define in_softirq()		(softirq_count())
+#define in_serving_softirq()	(softirq_count() & SOFTIRQ_OFFSET)
+
+#endif
 
 /*
  * The preempt_count offset after preempt_disable();
@@ -115,7 +124,11 @@
 /*
  * The preempt_count offset after spin_lock()
  */
+#if !defined(CONFIG_PREEMPT_RT)
 #define PREEMPT_LOCK_OFFSET	PREEMPT_DISABLE_OFFSET
+#else
+#define PREEMPT_LOCK_OFFSET	0
+#endif
 
 /*
  * The preempt_count offset needed for things like:
@@ -164,6 +177,20 @@ extern void preempt_count_sub(int val);
 #define preempt_count_inc() preempt_count_add(1)
 #define preempt_count_dec() preempt_count_sub(1)
 
+#ifdef CONFIG_PREEMPT_LAZY
+#define add_preempt_lazy_count(val)	do { preempt_lazy_count() += (val); } while (0)
+#define sub_preempt_lazy_count(val)	do { preempt_lazy_count() -= (val); } while (0)
+#define inc_preempt_lazy_count()	add_preempt_lazy_count(1)
+#define dec_preempt_lazy_count()	sub_preempt_lazy_count(1)
+#define preempt_lazy_count()		(current_thread_info()->preempt_lazy_count)
+#else
+#define add_preempt_lazy_count(val)	do { } while (0)
+#define sub_preempt_lazy_count(val)	do { } while (0)
+#define inc_preempt_lazy_count()	do { } while (0)
+#define dec_preempt_lazy_count()	do { } while (0)
+#define preempt_lazy_count()		(0)
+#endif
+
 #ifdef CONFIG_PREEMPT_COUNT
 
 #define preempt_disable() \
@@ -172,16 +199,53 @@ do { \
 	barrier(); \
 } while (0)
 
+#define preempt_lazy_disable() \
+do { \
+	inc_preempt_lazy_count(); \
+	barrier(); \
+} while (0)
+
 #define sched_preempt_enable_no_resched() \
 do { \
 	barrier(); \
 	preempt_count_dec(); \
 } while (0)
 
-#define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+#ifdef CONFIG_PREEMPT_RT
+# define preempt_enable_no_resched() sched_preempt_enable_no_resched()
+# define preempt_check_resched_rt() preempt_check_resched()
+#else
+# define preempt_enable_no_resched() preempt_enable()
+# define preempt_check_resched_rt() barrier();
+#endif
 
 #define preemptible()	(preempt_count() == 0 && !irqs_disabled())
 
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+
+extern void migrate_disable(void);
+extern void migrate_enable(void);
+
+int __migrate_disabled(struct task_struct *p);
+
+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+
+extern void migrate_disable(void);
+extern void migrate_enable(void);
+static inline int __migrate_disabled(struct task_struct *p)
+{
+	return 0;
+}
+
+#else
+#define migrate_disable()		preempt_disable()
+#define migrate_enable()		preempt_enable()
+static inline int __migrate_disabled(struct task_struct *p)
+{
+	return 0;
+}
+#endif
+
 #ifdef CONFIG_PREEMPTION
 #define preempt_enable() \
 do { \
@@ -203,6 +267,13 @@ do { \
 		__preempt_schedule(); \
 } while (0)
 
+#define preempt_lazy_enable() \
+do { \
+	dec_preempt_lazy_count(); \
+	barrier(); \
+	preempt_check_resched(); \
+} while (0)
+
 #else /* !CONFIG_PREEMPTION */
 #define preempt_enable() \
 do { \
@@ -210,6 +281,12 @@ do { \
 	preempt_count_dec(); \
 } while (0)
 
+#define preempt_lazy_enable() \
+do { \
+	dec_preempt_lazy_count(); \
+	barrier(); \
+} while (0)
+
 #define preempt_enable_notrace() \
 do { \
 	barrier(); \
@@ -248,8 +325,16 @@ do { \
 #define preempt_disable_notrace()		barrier()
 #define preempt_enable_no_resched_notrace()	barrier()
 #define preempt_enable_notrace()		barrier()
+#define preempt_check_resched_rt()		barrier()
 #define preemptible()				0
 
+#define migrate_disable()			barrier()
+#define migrate_enable()			barrier()
+
+static inline int __migrate_disabled(struct task_struct *p)
+{
+	return 0;
+}
 #endif /* CONFIG_PREEMPT_COUNT */
 
 #ifdef MODULE
@@ -268,10 +353,22 @@ do { \
 } while (0)
 #define preempt_fold_need_resched() \
 do { \
-	if (tif_need_resched()) \
+	if (tif_need_resched_now()) \
 		set_preempt_need_resched(); \
 } while (0)
 
+#ifdef CONFIG_PREEMPT_RT
+# define preempt_disable_rt()		preempt_disable()
+# define preempt_enable_rt()		preempt_enable()
+# define preempt_disable_nort()		barrier()
+# define preempt_enable_nort()		barrier()
+#else
+# define preempt_disable_rt()		barrier()
+# define preempt_enable_rt()		barrier()
+# define preempt_disable_nort()		preempt_disable()
+# define preempt_enable_nort()		preempt_enable()
+#endif
+
 #ifdef CONFIG_PREEMPT_NOTIFIERS
 
 struct preempt_notifier;
Index: linux-5.4.5-rt3/include/linux/printk.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/printk.h
+++ linux-5.4.5-rt3/include/linux/printk.h
@@ -58,6 +58,7 @@ static inline const char *printk_skip_he
  */
 #define CONSOLE_LOGLEVEL_DEFAULT CONFIG_CONSOLE_LOGLEVEL_DEFAULT
 #define CONSOLE_LOGLEVEL_QUIET	 CONFIG_CONSOLE_LOGLEVEL_QUIET
+#define CONSOLE_LOGLEVEL_EMERGENCY CONFIG_CONSOLE_LOGLEVEL_EMERGENCY
 
 extern int console_printk[];
 
@@ -65,6 +66,7 @@ extern int console_printk[];
 #define default_message_loglevel (console_printk[1])
 #define minimum_console_loglevel (console_printk[2])
 #define default_console_loglevel (console_printk[3])
+#define emergency_console_loglevel (console_printk[4])
 
 static inline void console_silent(void)
 {
@@ -146,18 +148,6 @@ static inline __printf(1, 2) __cold
 void early_printk(const char *s, ...) { }
 #endif
 
-#ifdef CONFIG_PRINTK_NMI
-extern void printk_nmi_enter(void);
-extern void printk_nmi_exit(void);
-extern void printk_nmi_direct_enter(void);
-extern void printk_nmi_direct_exit(void);
-#else
-static inline void printk_nmi_enter(void) { }
-static inline void printk_nmi_exit(void) { }
-static inline void printk_nmi_direct_enter(void) { }
-static inline void printk_nmi_direct_exit(void) { }
-#endif /* PRINTK_NMI */
-
 #ifdef CONFIG_PRINTK
 asmlinkage __printf(5, 0)
 int vprintk_emit(int facility, int level,
@@ -202,9 +192,7 @@ __printf(1, 2) void dump_stack_set_arch_
 void dump_stack_print_info(const char *log_lvl);
 void show_regs_print_info(const char *log_lvl);
 extern asmlinkage void dump_stack(void) __cold;
-extern void printk_safe_init(void);
-extern void printk_safe_flush(void);
-extern void printk_safe_flush_on_panic(void);
+struct wait_queue_head *printk_wait_queue(void);
 #else
 static inline __printf(1, 0)
 int vprintk(const char *s, va_list args)
@@ -268,18 +256,6 @@ static inline void show_regs_print_info(
 static inline void dump_stack(void)
 {
 }
-
-static inline void printk_safe_init(void)
-{
-}
-
-static inline void printk_safe_flush(void)
-{
-}
-
-static inline void printk_safe_flush_on_panic(void)
-{
-}
 #endif
 
 extern int kptr_restrict;
Index: linux-5.4.5-rt3/include/linux/printk_ringbuffer.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/printk_ringbuffer.h
@@ -0,0 +1,114 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_PRINTK_RINGBUFFER_H
+#define _LINUX_PRINTK_RINGBUFFER_H
+
+#include <linux/irq_work.h>
+#include <linux/atomic.h>
+#include <linux/percpu.h>
+#include <linux/wait.h>
+
+struct prb_cpulock {
+	atomic_t owner;
+	unsigned long __percpu *irqflags;
+};
+
+struct printk_ringbuffer {
+	void *buffer;
+	unsigned int size_bits;
+
+	u64 seq;
+	atomic_long_t lost;
+
+	atomic_long_t tail;
+	atomic_long_t head;
+	atomic_long_t reserve;
+
+	struct prb_cpulock *cpulock;
+	atomic_t ctx;
+
+	struct wait_queue_head *wq;
+	atomic_long_t wq_counter;
+	struct irq_work *wq_work;
+};
+
+struct prb_entry {
+	unsigned int size;
+	u64 seq;
+	char data[0];
+};
+
+struct prb_handle {
+	struct printk_ringbuffer *rb;
+	unsigned int cpu;
+	struct prb_entry *entry;
+};
+
+#define DECLARE_STATIC_PRINTKRB_CPULOCK(name)				\
+static DEFINE_PER_CPU(unsigned long, _##name##_percpu_irqflags);	\
+static struct prb_cpulock name = {					\
+	.owner = ATOMIC_INIT(-1),					\
+	.irqflags = &_##name##_percpu_irqflags,				\
+}
+
+#define PRB_INIT ((unsigned long)-1)
+
+#define DECLARE_STATIC_PRINTKRB_ITER(name, rbaddr)			\
+static struct prb_iterator name = {					\
+	.rb = rbaddr,							\
+	.lpos = PRB_INIT,						\
+}
+
+struct prb_iterator {
+	struct printk_ringbuffer *rb;
+	unsigned long lpos;
+};
+
+#define DECLARE_STATIC_PRINTKRB(name, szbits, cpulockptr)		\
+static char _##name##_buffer[1 << (szbits)]				\
+	__aligned(__alignof__(long));					\
+static DECLARE_WAIT_QUEUE_HEAD(_##name##_wait);				\
+static void _##name##_wake_work_func(struct irq_work *irq_work)		\
+{									\
+	wake_up_interruptible_all(&_##name##_wait);			\
+}									\
+static struct irq_work _##name##_wake_work = {				\
+	.func = _##name##_wake_work_func,				\
+	.flags = IRQ_WORK_LAZY,						\
+};									\
+static struct printk_ringbuffer name = {				\
+	.buffer = &_##name##_buffer[0],					\
+	.size_bits = szbits,						\
+	.seq = 0,							\
+	.lost = ATOMIC_LONG_INIT(0),					\
+	.tail = ATOMIC_LONG_INIT(-111 * sizeof(long)),			\
+	.head = ATOMIC_LONG_INIT(-111 * sizeof(long)),			\
+	.reserve = ATOMIC_LONG_INIT(-111 * sizeof(long)),		\
+	.cpulock = cpulockptr,						\
+	.ctx = ATOMIC_INIT(0),						\
+	.wq = &_##name##_wait,						\
+	.wq_counter = ATOMIC_LONG_INIT(0),				\
+	.wq_work = &_##name##_wake_work,				\
+}
+
+/* writer interface */
+char *prb_reserve(struct prb_handle *h, struct printk_ringbuffer *rb,
+		  unsigned int size);
+void prb_commit(struct prb_handle *h);
+
+/* reader interface */
+void prb_iter_init(struct prb_iterator *iter, struct printk_ringbuffer *rb,
+		   u64 *seq);
+void prb_iter_copy(struct prb_iterator *dest, struct prb_iterator *src);
+int prb_iter_next(struct prb_iterator *iter, char *buf, int size, u64 *seq);
+int prb_iter_wait_next(struct prb_iterator *iter, char *buf, int size,
+		       u64 *seq);
+int prb_iter_seek(struct prb_iterator *iter, u64 seq);
+int prb_iter_data(struct prb_iterator *iter, char *buf, int size, u64 *seq);
+
+/* utility functions */
+int prb_buffer_size(struct printk_ringbuffer *rb);
+void prb_inc_lost(struct printk_ringbuffer *rb);
+void prb_lock(struct prb_cpulock *cpu_lock, unsigned int *cpu_store);
+void prb_unlock(struct prb_cpulock *cpu_lock, unsigned int cpu_store);
+
+#endif /*_LINUX_PRINTK_RINGBUFFER_H */
Index: linux-5.4.5-rt3/include/linux/radix-tree.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/radix-tree.h
+++ linux-5.4.5-rt3/include/linux/radix-tree.h
@@ -226,6 +226,7 @@ unsigned int radix_tree_gang_lookup(cons
 			unsigned int max_items);
 int radix_tree_preload(gfp_t gfp_mask);
 int radix_tree_maybe_preload(gfp_t gfp_mask);
+void radix_tree_preload_end(void);
 void radix_tree_init(void);
 void *radix_tree_tag_set(struct radix_tree_root *,
 			unsigned long index, unsigned int tag);
@@ -243,11 +244,6 @@ unsigned int radix_tree_gang_lookup_tag_
 		unsigned int max_items, unsigned int tag);
 int radix_tree_tagged(const struct radix_tree_root *, unsigned int tag);
 
-static inline void radix_tree_preload_end(void)
-{
-	preempt_enable();
-}
-
 void __rcu **idr_get_free(struct radix_tree_root *root,
 			      struct radix_tree_iter *iter, gfp_t gfp,
 			      unsigned long max);
Index: linux-5.4.5-rt3/include/linux/random.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/random.h
+++ linux-5.4.5-rt3/include/linux/random.h
@@ -33,7 +33,7 @@ static inline void add_latent_entropy(vo
 
 extern void add_input_randomness(unsigned int type, unsigned int code,
 				 unsigned int value) __latent_entropy;
-extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
+extern void add_interrupt_randomness(int irq, int irq_flags, __u64 ip) __latent_entropy;
 
 extern void get_random_bytes(void *buf, int nbytes);
 extern int wait_for_random_bytes(void);
Index: linux-5.4.5-rt3/include/linux/ratelimit.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/ratelimit.h
+++ linux-5.4.5-rt3/include/linux/ratelimit.h
@@ -59,7 +59,7 @@ static inline void ratelimit_state_exit(
 		return;
 
 	if (rs->missed) {
-		pr_warn("%s: %d output lines suppressed due to ratelimiting\n",
+		pr_info("%s: %d output lines suppressed due to ratelimiting\n",
 			current->comm, rs->missed);
 		rs->missed = 0;
 	}
Index: linux-5.4.5-rt3/include/linux/rbtree.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/rbtree.h
+++ linux-5.4.5-rt3/include/linux/rbtree.h
@@ -19,7 +19,7 @@
 
 #include <linux/kernel.h>
 #include <linux/stddef.h>
-#include <linux/rcupdate.h>
+#include <linux/rcu_assign_pointer.h>
 
 struct rb_node {
 	unsigned long  __rb_parent_color;
Index: linux-5.4.5-rt3/include/linux/rcu_assign_pointer.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/rcu_assign_pointer.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef __LINUX_RCU_ASSIGN_POINTER_H__
+#define __LINUX_RCU_ASSIGN_POINTER_H__
+#include <linux/compiler.h>
+#include <asm/barrier.h>
+
+#ifdef __CHECKER__
+#define rcu_check_sparse(p, space) \
+	((void)(((typeof(*p) space *)p) == p))
+#else /* #ifdef __CHECKER__ */
+#define rcu_check_sparse(p, space)
+#endif /* #else #ifdef __CHECKER__ */
+
+/**
+ * RCU_INITIALIZER() - statically initialize an RCU-protected global variable
+ * @v: The value to statically initialize with.
+ */
+#define RCU_INITIALIZER(v) (typeof(*(v)) __force __rcu *)(v)
+
+/**
+ * rcu_assign_pointer() - assign to RCU-protected pointer
+ * @p: pointer to assign to
+ * @v: value to assign (publish)
+ *
+ * Assigns the specified value to the specified RCU-protected
+ * pointer, ensuring that any concurrent RCU readers will see
+ * any prior initialization.
+ *
+ * Inserts memory barriers on architectures that require them
+ * (which is most of them), and also prevents the compiler from
+ * reordering the code that initializes the structure after the pointer
+ * assignment.  More importantly, this call documents which pointers
+ * will be dereferenced by RCU read-side code.
+ *
+ * In some special cases, you may use RCU_INIT_POINTER() instead
+ * of rcu_assign_pointer().  RCU_INIT_POINTER() is a bit faster due
+ * to the fact that it does not constrain either the CPU or the compiler.
+ * That said, using RCU_INIT_POINTER() when you should have used
+ * rcu_assign_pointer() is a very bad thing that results in
+ * impossible-to-diagnose memory corruption.  So please be careful.
+ * See the RCU_INIT_POINTER() comment header for details.
+ *
+ * Note that rcu_assign_pointer() evaluates each of its arguments only
+ * once, appearances notwithstanding.  One of the "extra" evaluations
+ * is in typeof() and the other visible only to sparse (__CHECKER__),
+ * neither of which actually execute the argument.  As with most cpp
+ * macros, this execute-arguments-only-once property is important, so
+ * please be careful when making changes to rcu_assign_pointer() and the
+ * other macros that it invokes.
+ */
+#define rcu_assign_pointer(p, v)					\
+do {									\
+	uintptr_t _r_a_p__v = (uintptr_t)(v);				\
+	rcu_check_sparse(p, __rcu);					\
+									\
+	if (__builtin_constant_p(v) && (_r_a_p__v) == (uintptr_t)NULL)	\
+		WRITE_ONCE((p), (typeof(p))(_r_a_p__v));		\
+	else								\
+		smp_store_release(&p, RCU_INITIALIZER((typeof(p))_r_a_p__v));	\
+} while (0)
+
+#endif
Index: linux-5.4.5-rt3/include/linux/rcupdate.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/rcupdate.h
+++ linux-5.4.5-rt3/include/linux/rcupdate.h
@@ -29,6 +29,7 @@
 #include <linux/lockdep.h>
 #include <asm/processor.h>
 #include <linux/cpumask.h>
+#include <linux/rcu_assign_pointer.h>
 
 #define ULONG_CMP_GE(a, b)	(ULONG_MAX / 2 >= (a) - (b))
 #define ULONG_CMP_LT(a, b)	(ULONG_MAX / 2 < (a) - (b))
@@ -51,6 +52,11 @@ void __rcu_read_unlock(void);
  * types of kernel builds, the rcu_read_lock() nesting depth is unknowable.
  */
 #define rcu_preempt_depth() (current->rcu_read_lock_nesting)
+#ifndef CONFIG_PREEMPT_RT
+#define sched_rcu_preempt_depth()	rcu_preempt_depth()
+#else
+static inline int sched_rcu_preempt_depth(void) { return 0; }
+#endif
 
 #else /* #ifdef CONFIG_PREEMPT_RCU */
 
@@ -69,6 +75,8 @@ static inline int rcu_preempt_depth(void
 	return 0;
 }
 
+#define sched_rcu_preempt_depth()	rcu_preempt_depth()
+
 #endif /* #else #ifdef CONFIG_PREEMPT_RCU */
 
 /* Internal to kernel */
@@ -154,7 +162,7 @@ static inline void exit_tasks_rcu_finish
  *
  * This macro resembles cond_resched(), except that it is defined to
  * report potential quiescent states to RCU-tasks even if the cond_resched()
- * machinery were to be shut off, as some advocate for PREEMPT kernels.
+ * machinery were to be shut off, as some advocate for PREEMPTION kernels.
  */
 #define cond_resched_tasks_rcu_qs() \
 do { \
@@ -279,7 +287,8 @@ static inline void rcu_preempt_sleep_che
 #define rcu_sleep_check()						\
 	do {								\
 		rcu_preempt_sleep_check();				\
-		RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
+		if (!IS_ENABLED(CONFIG_PREEMPT_RT))		\
+		    RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),	\
 				 "Illegal context switch in RCU-bh read-side critical section"); \
 		RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map),	\
 				 "Illegal context switch in RCU-sched read-side critical section"); \
@@ -300,13 +309,6 @@ static inline void rcu_preempt_sleep_che
  * (e.g., __srcu), should this make sense in the future.
  */
 
-#ifdef __CHECKER__
-#define rcu_check_sparse(p, space) \
-	((void)(((typeof(*p) space *)p) == p))
-#else /* #ifdef __CHECKER__ */
-#define rcu_check_sparse(p, space)
-#endif /* #else #ifdef __CHECKER__ */
-
 #define __rcu_access_pointer(p, space) \
 ({ \
 	typeof(*p) *_________p1 = (typeof(*p) *__force)READ_ONCE(p); \
@@ -335,54 +337,6 @@ static inline void rcu_preempt_sleep_che
 })
 
 /**
- * RCU_INITIALIZER() - statically initialize an RCU-protected global variable
- * @v: The value to statically initialize with.
- */
-#define RCU_INITIALIZER(v) (typeof(*(v)) __force __rcu *)(v)
-
-/**
- * rcu_assign_pointer() - assign to RCU-protected pointer
- * @p: pointer to assign to
- * @v: value to assign (publish)
- *
- * Assigns the specified value to the specified RCU-protected
- * pointer, ensuring that any concurrent RCU readers will see
- * any prior initialization.
- *
- * Inserts memory barriers on architectures that require them
- * (which is most of them), and also prevents the compiler from
- * reordering the code that initializes the structure after the pointer
- * assignment.  More importantly, this call documents which pointers
- * will be dereferenced by RCU read-side code.
- *
- * In some special cases, you may use RCU_INIT_POINTER() instead
- * of rcu_assign_pointer().  RCU_INIT_POINTER() is a bit faster due
- * to the fact that it does not constrain either the CPU or the compiler.
- * That said, using RCU_INIT_POINTER() when you should have used
- * rcu_assign_pointer() is a very bad thing that results in
- * impossible-to-diagnose memory corruption.  So please be careful.
- * See the RCU_INIT_POINTER() comment header for details.
- *
- * Note that rcu_assign_pointer() evaluates each of its arguments only
- * once, appearances notwithstanding.  One of the "extra" evaluations
- * is in typeof() and the other visible only to sparse (__CHECKER__),
- * neither of which actually execute the argument.  As with most cpp
- * macros, this execute-arguments-only-once property is important, so
- * please be careful when making changes to rcu_assign_pointer() and the
- * other macros that it invokes.
- */
-#define rcu_assign_pointer(p, v)					      \
-do {									      \
-	uintptr_t _r_a_p__v = (uintptr_t)(v);				      \
-	rcu_check_sparse(p, __rcu);					      \
-									      \
-	if (__builtin_constant_p(v) && (_r_a_p__v) == (uintptr_t)NULL)	      \
-		WRITE_ONCE((p), (typeof(p))(_r_a_p__v));		      \
-	else								      \
-		smp_store_release(&p, RCU_INITIALIZER((typeof(p))_r_a_p__v)); \
-} while (0)
-
-/**
  * rcu_swap_protected() - swap an RCU and a regular pointer
  * @rcu_ptr: RCU pointer
  * @ptr: regular pointer
@@ -580,7 +534,7 @@ do {									      \
  *
  * You can avoid reading and understanding the next paragraph by
  * following this rule: don't put anything in an rcu_read_lock() RCU
- * read-side critical section that would block in a !PREEMPT kernel.
+ * read-side critical section that would block in a !PREEMPTION kernel.
  * But if you want the full story, read on!
  *
  * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU),
Index: linux-5.4.5-rt3/include/linux/rtmutex.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/rtmutex.h
+++ linux-5.4.5-rt3/include/linux/rtmutex.h
@@ -14,11 +14,15 @@
 #define __LINUX_RT_MUTEX_H
 
 #include <linux/linkage.h>
+#include <linux/spinlock_types_raw.h>
 #include <linux/rbtree.h>
-#include <linux/spinlock_types.h>
 
 extern int max_lock_depth; /* for sysctl */
 
+#ifdef CONFIG_DEBUG_MUTEXES
+#include <linux/debug_locks.h>
+#endif
+
 /**
  * The rt_mutex structure
  *
@@ -31,8 +35,8 @@ struct rt_mutex {
 	raw_spinlock_t		wait_lock;
 	struct rb_root_cached   waiters;
 	struct task_struct	*owner;
-#ifdef CONFIG_DEBUG_RT_MUTEXES
 	int			save_state;
+#ifdef CONFIG_DEBUG_RT_MUTEXES
 	const char		*name, *file;
 	int			line;
 	void			*magic;
@@ -82,16 +86,23 @@ do { \
 #define __DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
 #endif
 
-#define __RT_MUTEX_INITIALIZER(mutexname) \
-	{ .wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
+#define __RT_MUTEX_INITIALIZER_PLAIN(mutexname) \
+	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(mutexname.wait_lock) \
 	, .waiters = RB_ROOT_CACHED \
 	, .owner = NULL \
 	__DEBUG_RT_MUTEX_INITIALIZER(mutexname) \
-	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)}
+	__DEP_MAP_RT_MUTEX_INITIALIZER(mutexname)
+
+#define __RT_MUTEX_INITIALIZER(mutexname) \
+	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname) }
 
 #define DEFINE_RT_MUTEX(mutexname) \
 	struct rt_mutex mutexname = __RT_MUTEX_INITIALIZER(mutexname)
 
+#define __RT_MUTEX_INITIALIZER_SAVE_STATE(mutexname) \
+	{ __RT_MUTEX_INITIALIZER_PLAIN(mutexname)    \
+		, .save_state = 1 }
+
 /**
  * rt_mutex_is_locked - is the mutex locked
  * @lock: the mutex to be queried
@@ -115,6 +126,7 @@ extern void rt_mutex_lock(struct rt_mute
 #endif
 
 extern int rt_mutex_lock_interruptible(struct rt_mutex *lock);
+extern int rt_mutex_lock_killable(struct rt_mutex *lock);
 extern int rt_mutex_timed_lock(struct rt_mutex *lock,
 			       struct hrtimer_sleeper *timeout);
 
Index: linux-5.4.5-rt3/include/linux/rwlock_rt.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/rwlock_rt.h
@@ -0,0 +1,119 @@
+#ifndef __LINUX_RWLOCK_RT_H
+#define __LINUX_RWLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+extern void __lockfunc rt_write_lock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_lock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_trylock(rwlock_t *rwlock);
+extern int __lockfunc rt_read_trylock(rwlock_t *rwlock);
+extern void __lockfunc rt_write_unlock(rwlock_t *rwlock);
+extern void __lockfunc rt_read_unlock(rwlock_t *rwlock);
+extern int __lockfunc rt_read_can_lock(rwlock_t *rwlock);
+extern int __lockfunc rt_write_can_lock(rwlock_t *rwlock);
+extern void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key);
+
+#define read_can_lock(rwlock)		rt_read_can_lock(rwlock)
+#define write_can_lock(rwlock)		rt_write_can_lock(rwlock)
+
+#define read_trylock(lock)	__cond_lock(lock, rt_read_trylock(lock))
+#define write_trylock(lock)	__cond_lock(lock, rt_write_trylock(lock))
+
+static inline int __write_trylock_rt_irqsave(rwlock_t *lock, unsigned long *flags)
+{
+	/* XXX ARCH_IRQ_ENABLED */
+	*flags = 0;
+	return rt_write_trylock(lock);
+}
+
+#define write_trylock_irqsave(lock, flags)		\
+	__cond_lock(lock, __write_trylock_rt_irqsave(lock, &(flags)))
+
+#define read_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		rt_read_lock(lock);			\
+		flags = 0;				\
+	} while (0)
+
+#define write_lock_irqsave(lock, flags)			\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		rt_write_lock(lock);			\
+		flags = 0;				\
+	} while (0)
+
+#define read_lock(lock)		rt_read_lock(lock)
+
+#define read_lock_bh(lock)				\
+	do {						\
+		local_bh_disable();			\
+		rt_read_lock(lock);			\
+	} while (0)
+
+#define read_lock_irq(lock)	read_lock(lock)
+
+#define write_lock(lock)	rt_write_lock(lock)
+
+#define write_lock_bh(lock)				\
+	do {						\
+		local_bh_disable();			\
+		rt_write_lock(lock);			\
+	} while (0)
+
+#define write_lock_irq(lock)	write_lock(lock)
+
+#define read_unlock(lock)	rt_read_unlock(lock)
+
+#define read_unlock_bh(lock)				\
+	do {						\
+		rt_read_unlock(lock);			\
+		local_bh_enable();			\
+	} while (0)
+
+#define read_unlock_irq(lock)	read_unlock(lock)
+
+#define write_unlock(lock)	rt_write_unlock(lock)
+
+#define write_unlock_bh(lock)				\
+	do {						\
+		rt_write_unlock(lock);			\
+		local_bh_enable();			\
+	} while (0)
+
+#define write_unlock_irq(lock)	write_unlock(lock)
+
+#define read_unlock_irqrestore(lock, flags)		\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		rt_read_unlock(lock);			\
+	} while (0)
+
+#define write_unlock_irqrestore(lock, flags) \
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		rt_write_unlock(lock);			\
+	} while (0)
+
+#define rwlock_init(rwl)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	__rt_rwlock_init(rwl, #rwl, &__key);		\
+} while (0)
+
+/*
+ * Internal functions made global for CPU pinning
+ */
+void __read_rt_lock(struct rt_rw_lock *lock);
+int __read_rt_trylock(struct rt_rw_lock *lock);
+void __write_rt_lock(struct rt_rw_lock *lock);
+int __write_rt_trylock(struct rt_rw_lock *lock);
+void __read_rt_unlock(struct rt_rw_lock *lock);
+void __write_rt_unlock(struct rt_rw_lock *lock);
+
+#endif
Index: linux-5.4.5-rt3/include/linux/rwlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/rwlock_types.h
+++ linux-5.4.5-rt3/include/linux/rwlock_types.h
@@ -1,6 +1,10 @@
 #ifndef __LINUX_RWLOCK_TYPES_H
 #define __LINUX_RWLOCK_TYPES_H
 
+#if !defined(__LINUX_SPINLOCK_TYPES_H)
+# error "Do not include directly, include spinlock_types.h"
+#endif
+
 /*
  * include/linux/rwlock_types.h - generic rwlock type definitions
  *				  and initializers
Index: linux-5.4.5-rt3/include/linux/rwlock_types_rt.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/rwlock_types_rt.h
@@ -0,0 +1,55 @@
+#ifndef __LINUX_RWLOCK_TYPES_RT_H
+#define __LINUX_RWLOCK_TYPES_RT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define RW_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+#else
+# define RW_DEP_MAP_INIT(lockname)
+#endif
+
+typedef struct rt_rw_lock rwlock_t;
+
+#define __RW_LOCK_UNLOCKED(name) __RWLOCK_RT_INITIALIZER(name)
+
+#define DEFINE_RWLOCK(name) \
+	rwlock_t name = __RW_LOCK_UNLOCKED(name)
+
+/*
+ * A reader biased implementation primarily for CPU pinning.
+ *
+ * Can be selected as general replacement for the single reader RT rwlock
+ * variant
+ */
+struct rt_rw_lock {
+	struct rt_mutex		rtmutex;
+	atomic_t		readers;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define READER_BIAS	(1U << 31)
+#define WRITER_BIAS	(1U << 30)
+
+#define __RWLOCK_RT_INITIALIZER(name)					\
+{									\
+	.readers = ATOMIC_INIT(READER_BIAS),				\
+	.rtmutex = __RT_MUTEX_INITIALIZER_SAVE_STATE(name.rtmutex),	\
+	RW_DEP_MAP_INIT(name)						\
+}
+
+void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
+			     struct lock_class_key *key);
+
+#define rwlock_biased_rt_init(rwlock)					\
+	do {								\
+		static struct lock_class_key __key;			\
+									\
+		__rwlock_biased_rt_init((rwlock), #rwlock, &__key);	\
+	} while (0)
+
+#endif
Index: linux-5.4.5-rt3/include/linux/rwsem-rt.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/rwsem-rt.h
@@ -0,0 +1,68 @@
+#ifndef _LINUX_RWSEM_RT_H
+#define _LINUX_RWSEM_RT_H
+
+#ifndef _LINUX_RWSEM_H
+#error "Include rwsem.h"
+#endif
+
+#include <linux/rtmutex.h>
+#include <linux/swait.h>
+
+#define READER_BIAS		(1U << 31)
+#define WRITER_BIAS		(1U << 30)
+
+struct rw_semaphore {
+	atomic_t		readers;
+	struct rt_mutex		rtmutex;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+};
+
+#define __RWSEM_INITIALIZER(name)				\
+{								\
+	.readers = ATOMIC_INIT(READER_BIAS),			\
+	.rtmutex = __RT_MUTEX_INITIALIZER(name.rtmutex),	\
+	RW_DEP_MAP_INIT(name)					\
+}
+
+#define DECLARE_RWSEM(lockname) \
+	struct rw_semaphore lockname = __RWSEM_INITIALIZER(lockname)
+
+extern void  __rwsem_init(struct rw_semaphore *rwsem, const char *name,
+			  struct lock_class_key *key);
+
+#define __init_rwsem(sem, name, key)			\
+do {							\
+		rt_mutex_init(&(sem)->rtmutex);		\
+		__rwsem_init((sem), (name), (key));	\
+} while (0)
+
+#define init_rwsem(sem)					\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	__init_rwsem((sem), #sem, &__key);		\
+} while (0)
+
+static inline int rwsem_is_locked(struct rw_semaphore *sem)
+{
+	return atomic_read(&sem->readers) != READER_BIAS;
+}
+
+static inline int rwsem_is_contended(struct rw_semaphore *sem)
+{
+	return atomic_read(&sem->readers) > 0;
+}
+
+extern void __down_read(struct rw_semaphore *sem);
+extern int __down_read_killable(struct rw_semaphore *sem);
+extern int __down_read_trylock(struct rw_semaphore *sem);
+extern void __down_write(struct rw_semaphore *sem);
+extern int __must_check __down_write_killable(struct rw_semaphore *sem);
+extern int __down_write_trylock(struct rw_semaphore *sem);
+extern void __up_read(struct rw_semaphore *sem);
+extern void __up_write(struct rw_semaphore *sem);
+extern void __downgrade_write(struct rw_semaphore *sem);
+
+#endif
Index: linux-5.4.5-rt3/include/linux/rwsem.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/rwsem.h
+++ linux-5.4.5-rt3/include/linux/rwsem.h
@@ -16,6 +16,11 @@
 #include <linux/spinlock.h>
 #include <linux/atomic.h>
 #include <linux/err.h>
+
+#ifdef CONFIG_PREEMPT_RT
+#include <linux/rwsem-rt.h>
+#else /* PREEMPT_RT */
+
 #ifdef CONFIG_RWSEM_SPIN_ON_OWNER
 #include <linux/osq_lock.h>
 #endif
@@ -53,12 +58,6 @@ struct rw_semaphore {
 #endif
 };
 
-/*
- * Setting all bits of the owner field except bit 0 will indicate
- * that the rwsem is writer-owned with an unknown owner.
- */
-#define RWSEM_OWNER_UNKNOWN	(-2L)
-
 /* In all implementations count != 0 means locked */
 static inline int rwsem_is_locked(struct rw_semaphore *sem)
 {
@@ -121,6 +120,13 @@ static inline int rwsem_is_contended(str
 	return !list_empty(&sem->wait_list);
 }
 
+#endif /* !PREEMPT_RT */
+
+/*
+ * The functions below are the same for all rwsem implementations including
+ * the RT specific variant.
+ */
+
 /*
  * lock for reading
  */
Index: linux-5.4.5-rt3/include/linux/sched.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/sched.h
+++ linux-5.4.5-rt3/include/linux/sched.h
@@ -31,6 +31,7 @@
 #include <linux/task_io_accounting.h>
 #include <linux/posix-timers.h>
 #include <linux/rseq.h>
+#include <asm/kmap_types.h>
 
 /* task_struct member predeclarations (sorted alphabetically): */
 struct audit_context;
@@ -107,12 +108,8 @@ struct task_group;
 					 __TASK_TRACED | EXIT_DEAD | EXIT_ZOMBIE | \
 					 TASK_PARKED)
 
-#define task_is_traced(task)		((task->state & __TASK_TRACED) != 0)
-
 #define task_is_stopped(task)		((task->state & __TASK_STOPPED) != 0)
 
-#define task_is_stopped_or_traced(task)	((task->state & (__TASK_STOPPED | __TASK_TRACED)) != 0)
-
 #define task_contributes_to_load(task)	((task->state & TASK_UNINTERRUPTIBLE) != 0 && \
 					 (task->flags & PF_FROZEN) == 0 && \
 					 (task->state & TASK_NOLOAD) == 0)
@@ -140,6 +137,9 @@ struct task_group;
 		smp_store_mb(current->state, (state_value));	\
 	} while (0)
 
+#define __set_current_state_no_track(state_value)		\
+	current->state = (state_value);
+
 #define set_special_state(state_value)					\
 	do {								\
 		unsigned long flags; /* may shadow */			\
@@ -149,6 +149,7 @@ struct task_group;
 		current->state = (state_value);				\
 		raw_spin_unlock_irqrestore(&current->pi_lock, flags);	\
 	} while (0)
+
 #else
 /*
  * set_current_state() includes a barrier so that the write of current->state
@@ -193,6 +194,9 @@ struct task_group;
 #define set_current_state(state_value)					\
 	smp_store_mb(current->state, (state_value))
 
+#define __set_current_state_no_track(state_value)	\
+	__set_current_state(state_value)
+
 /*
  * set_special_state() should be used for those states when the blocking task
  * can not use the regular condition based wait-loop. In that case we must
@@ -230,6 +234,8 @@ extern void io_schedule_finish(int token
 extern long io_schedule_timeout(long timeout);
 extern void io_schedule(void);
 
+int cpu_nr_pinned(int cpu);
+
 /**
  * struct prev_cputime - snapshot of system and user cputime
  * @utime: time spent in user mode
@@ -631,6 +637,8 @@ struct task_struct {
 #endif
 	/* -1 unrunnable, 0 runnable, >0 stopped: */
 	volatile long			state;
+	/* saved state for "spinlock sleepers" */
+	volatile long			saved_state;
 
 	/*
 	 * This begins the randomizable portion of task_struct. Only
@@ -700,6 +708,20 @@ struct task_struct {
 	int				nr_cpus_allowed;
 	const cpumask_t			*cpus_ptr;
 	cpumask_t			cpus_mask;
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+	int				migrate_disable;
+	bool				migrate_disable_scheduled;
+# ifdef CONFIG_SCHED_DEBUG
+	int				pinned_on_cpu;
+# endif
+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+# ifdef CONFIG_SCHED_DEBUG
+	int				migrate_disable;
+# endif
+#endif
+#ifdef CONFIG_PREEMPT_RT
+	int				sleeping_lock;
+#endif
 
 #ifdef CONFIG_PREEMPT_RCU
 	int				rcu_read_lock_nesting;
@@ -913,11 +935,17 @@ struct task_struct {
 	/* Signal handlers: */
 	struct signal_struct		*signal;
 	struct sighand_struct		*sighand;
+	struct sigqueue			*sigqueue_cache;
+
 	sigset_t			blocked;
 	sigset_t			real_blocked;
 	/* Restored if set_restore_sigmask() was used: */
 	sigset_t			saved_sigmask;
 	struct sigpending		pending;
+#ifdef CONFIG_PREEMPT_RT
+	/* TODO: move me into ->restart_block ? */
+	struct				kernel_siginfo forced_info;
+#endif
 	unsigned long			sas_ss_sp;
 	size_t				sas_ss_size;
 	unsigned int			sas_ss_flags;
@@ -944,6 +972,7 @@ struct task_struct {
 	raw_spinlock_t			pi_lock;
 
 	struct wake_q_node		wake_q;
+	struct wake_q_node		wake_q_sleeper;
 
 #ifdef CONFIG_RT_MUTEXES
 	/* PI waiters blocked on a rt_mutex held by this task: */
@@ -978,6 +1007,9 @@ struct task_struct {
 	int				softirqs_enabled;
 	int				softirq_context;
 #endif
+#ifdef CONFIG_PREEMPT_RT
+	int				softirq_count;
+#endif
 
 #ifdef CONFIG_LOCKDEP
 # define MAX_LOCK_DEPTH			48UL
@@ -1241,6 +1273,12 @@ struct task_struct {
 	unsigned int			sequential_io;
 	unsigned int			sequential_io_avg;
 #endif
+#ifdef CONFIG_PREEMPT_RT
+# if defined CONFIG_HIGHMEM || defined CONFIG_X86_32
+	int				kmap_idx;
+	pte_t				kmap_pte[KM_TYPE_NR];
+# endif
+#endif
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 	unsigned long			task_state_change;
 #endif
@@ -1672,6 +1710,7 @@ extern struct task_struct *find_get_task
 
 extern int wake_up_state(struct task_struct *tsk, unsigned int state);
 extern int wake_up_process(struct task_struct *tsk);
+extern int wake_up_lock_sleeper(struct task_struct *tsk);
 extern void wake_up_new_task(struct task_struct *tsk);
 
 #ifdef CONFIG_SMP
@@ -1754,6 +1793,89 @@ static inline int test_tsk_need_resched(
 	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED));
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+static inline void set_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	set_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
+}
+
+static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	clear_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY);
+}
+
+static inline int test_tsk_need_resched_lazy(struct task_struct *tsk)
+{
+	return unlikely(test_tsk_thread_flag(tsk,TIF_NEED_RESCHED_LAZY));
+}
+
+static inline int need_resched_lazy(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED_LAZY);
+}
+
+static inline int need_resched_now(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+
+#else
+static inline void clear_tsk_need_resched_lazy(struct task_struct *tsk) { }
+static inline int need_resched_lazy(void) { return 0; }
+
+static inline int need_resched_now(void)
+{
+	return test_thread_flag(TIF_NEED_RESCHED);
+}
+
+#endif
+
+
+static inline bool __task_is_stopped_or_traced(struct task_struct *task)
+{
+	if (task->state & (__TASK_STOPPED | __TASK_TRACED))
+		return true;
+#ifdef CONFIG_PREEMPT_RT
+	if (task->saved_state & (__TASK_STOPPED | __TASK_TRACED))
+		return true;
+#endif
+	return false;
+}
+
+static inline bool task_is_stopped_or_traced(struct task_struct *task)
+{
+	bool traced_stopped;
+
+#ifdef CONFIG_PREEMPT_RT
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&task->pi_lock, flags);
+	traced_stopped = __task_is_stopped_or_traced(task);
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
+#else
+	traced_stopped = __task_is_stopped_or_traced(task);
+#endif
+	return traced_stopped;
+}
+
+static inline bool task_is_traced(struct task_struct *task)
+{
+	bool traced = false;
+
+	if (task->state & __TASK_TRACED)
+		return true;
+#ifdef CONFIG_PREEMPT_RT
+	/* in case the task is sleeping on tasklist_lock */
+	raw_spin_lock_irq(&task->pi_lock);
+	if (task->state & __TASK_TRACED)
+		traced = true;
+	else if (task->saved_state & __TASK_TRACED)
+		traced = true;
+	raw_spin_unlock_irq(&task->pi_lock);
+#endif
+	return traced;
+}
+
 /*
  * cond_resched() and cond_resched_lock(): latency reduction via
  * explicit rescheduling in places that are safe. The return
@@ -1806,6 +1928,23 @@ static __always_inline bool need_resched
 	return unlikely(tif_need_resched());
 }
 
+#ifdef CONFIG_PREEMPT_RT
+static inline void sleeping_lock_inc(void)
+{
+	current->sleeping_lock++;
+}
+
+static inline void sleeping_lock_dec(void)
+{
+	current->sleeping_lock--;
+}
+
+#else
+
+static inline void sleeping_lock_inc(void) { }
+static inline void sleeping_lock_dec(void) { }
+#endif
+
 /*
  * Wrappers for p->thread_info->cpu access. No-op on UP.
  */
@@ -1997,4 +2136,6 @@ int sched_trace_rq_cpu(struct rq *rq);
 
 const struct cpumask *sched_trace_rd_span(struct root_domain *rd);
 
+extern struct task_struct *takedown_cpu_task;
+
 #endif
Index: linux-5.4.5-rt3/include/linux/sched/mm.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/sched/mm.h
+++ linux-5.4.5-rt3/include/linux/sched/mm.h
@@ -49,6 +49,17 @@ static inline void mmdrop(struct mm_stru
 		__mmdrop(mm);
 }
 
+#ifdef CONFIG_PREEMPT_RT
+extern void __mmdrop_delayed(struct rcu_head *rhp);
+static inline void mmdrop_delayed(struct mm_struct *mm)
+{
+	if (atomic_dec_and_test(&mm->mm_count))
+		call_rcu(&mm->delayed_drop, __mmdrop_delayed);
+}
+#else
+# define mmdrop_delayed(mm)	mmdrop(mm)
+#endif
+
 /*
  * This has to be called after a get_task_mm()/mmget_not_zero()
  * followed by taking the mmap_sem for writing before modifying the
Index: linux-5.4.5-rt3/include/linux/sched/wake_q.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/sched/wake_q.h
+++ linux-5.4.5-rt3/include/linux/sched/wake_q.h
@@ -58,6 +58,17 @@ static inline bool wake_q_empty(struct w
 
 extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
 extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
-extern void wake_up_q(struct wake_q_head *head);
+extern void wake_q_add_sleeper(struct wake_q_head *head, struct task_struct *task);
+extern void __wake_up_q(struct wake_q_head *head, bool sleeper);
+
+static inline void wake_up_q(struct wake_q_head *head)
+{
+	__wake_up_q(head, false);
+}
+
+static inline void wake_up_q_sleeper(struct wake_q_head *head)
+{
+	__wake_up_q(head, true);
+}
 
 #endif /* _LINUX_SCHED_WAKE_Q_H */
Index: linux-5.4.5-rt3/include/linux/seqlock.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/seqlock.h
+++ linux-5.4.5-rt3/include/linux/seqlock.h
@@ -221,20 +221,30 @@ static inline int read_seqcount_retry(co
 	return __read_seqcount_retry(s, start);
 }
 
-
-
-static inline void raw_write_seqcount_begin(seqcount_t *s)
+static inline void __raw_write_seqcount_begin(seqcount_t *s)
 {
 	s->sequence++;
 	smp_wmb();
 }
 
-static inline void raw_write_seqcount_end(seqcount_t *s)
+static inline void raw_write_seqcount_begin(seqcount_t *s)
+{
+	preempt_disable_rt();
+	__raw_write_seqcount_begin(s);
+}
+
+static inline void __raw_write_seqcount_end(seqcount_t *s)
 {
 	smp_wmb();
 	s->sequence++;
 }
 
+static inline void raw_write_seqcount_end(seqcount_t *s)
+{
+	__raw_write_seqcount_end(s);
+	preempt_enable_rt();
+}
+
 /**
  * raw_write_seqcount_barrier - do a seq write barrier
  * @s: pointer to seqcount_t
@@ -428,10 +438,33 @@ typedef struct {
 /*
  * Read side functions for starting and finalizing a read side section.
  */
+#ifndef CONFIG_PREEMPT_RT
 static inline unsigned read_seqbegin(const seqlock_t *sl)
 {
 	return read_seqcount_begin(&sl->seqcount);
 }
+#else
+/*
+ * Starvation safe read side for RT
+ */
+static inline unsigned read_seqbegin(seqlock_t *sl)
+{
+	unsigned ret;
+
+repeat:
+	ret = READ_ONCE(sl->seqcount.sequence);
+	if (unlikely(ret & 1)) {
+		/*
+		 * Take the lock and let the writer proceed (i.e. evtl
+		 * boost it), otherwise we could loop here forever.
+		 */
+		spin_unlock_wait(&sl->lock);
+		goto repeat;
+	}
+	smp_rmb();
+	return ret;
+}
+#endif
 
 static inline unsigned read_seqretry(const seqlock_t *sl, unsigned start)
 {
@@ -446,36 +479,45 @@ static inline unsigned read_seqretry(con
 static inline void write_seqlock(seqlock_t *sl)
 {
 	spin_lock(&sl->lock);
-	write_seqcount_begin(&sl->seqcount);
+	__raw_write_seqcount_begin(&sl->seqcount);
+}
+
+static inline int try_write_seqlock(seqlock_t *sl)
+{
+	if (spin_trylock(&sl->lock)) {
+		__raw_write_seqcount_begin(&sl->seqcount);
+		return 1;
+	}
+	return 0;
 }
 
 static inline void write_sequnlock(seqlock_t *sl)
 {
-	write_seqcount_end(&sl->seqcount);
+	__raw_write_seqcount_end(&sl->seqcount);
 	spin_unlock(&sl->lock);
 }
 
 static inline void write_seqlock_bh(seqlock_t *sl)
 {
 	spin_lock_bh(&sl->lock);
-	write_seqcount_begin(&sl->seqcount);
+	__raw_write_seqcount_begin(&sl->seqcount);
 }
 
 static inline void write_sequnlock_bh(seqlock_t *sl)
 {
-	write_seqcount_end(&sl->seqcount);
+	__raw_write_seqcount_end(&sl->seqcount);
 	spin_unlock_bh(&sl->lock);
 }
 
 static inline void write_seqlock_irq(seqlock_t *sl)
 {
 	spin_lock_irq(&sl->lock);
-	write_seqcount_begin(&sl->seqcount);
+	__raw_write_seqcount_begin(&sl->seqcount);
 }
 
 static inline void write_sequnlock_irq(seqlock_t *sl)
 {
-	write_seqcount_end(&sl->seqcount);
+	__raw_write_seqcount_end(&sl->seqcount);
 	spin_unlock_irq(&sl->lock);
 }
 
@@ -484,7 +526,7 @@ static inline unsigned long __write_seql
 	unsigned long flags;
 
 	spin_lock_irqsave(&sl->lock, flags);
-	write_seqcount_begin(&sl->seqcount);
+	__raw_write_seqcount_begin(&sl->seqcount);
 	return flags;
 }
 
@@ -494,7 +536,7 @@ static inline unsigned long __write_seql
 static inline void
 write_sequnlock_irqrestore(seqlock_t *sl, unsigned long flags)
 {
-	write_seqcount_end(&sl->seqcount);
+	__raw_write_seqcount_end(&sl->seqcount);
 	spin_unlock_irqrestore(&sl->lock, flags);
 }
 
Index: linux-5.4.5-rt3/include/linux/serial_8250.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/serial_8250.h
+++ linux-5.4.5-rt3/include/linux/serial_8250.h
@@ -7,6 +7,7 @@
 #ifndef _LINUX_SERIAL_8250_H
 #define _LINUX_SERIAL_8250_H
 
+#include <linux/atomic.h>
 #include <linux/serial_core.h>
 #include <linux/serial_reg.h>
 #include <linux/platform_device.h>
@@ -123,6 +124,8 @@ struct uart_8250_port {
 #define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
 	unsigned char		msr_saved_flags;
 
+	atomic_t		console_printing;
+
 	struct uart_8250_dma	*dma;
 	const struct uart_8250_ops *ops;
 
@@ -174,6 +177,8 @@ void serial8250_init_port(struct uart_82
 void serial8250_set_defaults(struct uart_8250_port *up);
 void serial8250_console_write(struct uart_8250_port *up, const char *s,
 			      unsigned int count);
+void serial8250_console_write_atomic(struct uart_8250_port *up, const char *s,
+				     unsigned int count);
 int serial8250_console_setup(struct uart_port *port, char *options, bool probe);
 
 extern void serial8250_set_isa_configurator(void (*v)
Index: linux-5.4.5-rt3/include/linux/signal.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/signal.h
+++ linux-5.4.5-rt3/include/linux/signal.h
@@ -255,6 +255,7 @@ static inline void init_sigpending(struc
 }
 
 extern void flush_sigqueue(struct sigpending *queue);
+extern void flush_task_sigqueue(struct task_struct *tsk);
 
 /* Test if 'sig' is valid signal. Use this instead of testing _NSIG directly */
 static inline int valid_signal(unsigned long sig)
Index: linux-5.4.5-rt3/include/linux/skbuff.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/skbuff.h
+++ linux-5.4.5-rt3/include/linux/skbuff.h
@@ -293,6 +293,7 @@ struct sk_buff_head {
 
 	__u32		qlen;
 	spinlock_t	lock;
+	raw_spinlock_t	raw_lock;
 };
 
 struct sk_buff;
@@ -1844,6 +1845,12 @@ static inline void skb_queue_head_init(s
 	__skb_queue_head_init(list);
 }
 
+static inline void skb_queue_head_init_raw(struct sk_buff_head *list)
+{
+	raw_spin_lock_init(&list->raw_lock);
+	__skb_queue_head_init(list);
+}
+
 static inline void skb_queue_head_init_class(struct sk_buff_head *list,
 		struct lock_class_key *class)
 {
Index: linux-5.4.5-rt3/include/linux/smp.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/smp.h
+++ linux-5.4.5-rt3/include/linux/smp.h
@@ -15,6 +15,7 @@
 #include <linux/llist.h>
 
 typedef void (*smp_call_func_t)(void *info);
+typedef bool (*smp_cond_func_t)(int cpu, void *info);
 struct __call_single_data {
 	struct llist_node llist;
 	smp_call_func_t func;
@@ -49,13 +50,11 @@ void on_each_cpu_mask(const struct cpuma
  * cond_func returns a positive value. This may include the local
  * processor.
  */
-void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
-		smp_call_func_t func, void *info, bool wait,
-		gfp_t gfp_flags);
-
-void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),
-		smp_call_func_t func, void *info, bool wait,
-		gfp_t gfp_flags, const struct cpumask *mask);
+void on_each_cpu_cond(smp_cond_func_t cond_func, smp_call_func_t func,
+		      void *info, bool wait);
+
+void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
+			   void *info, bool wait, const struct cpumask *mask);
 
 int smp_call_function_single_async(int cpu, call_single_data_t *csd);
 
@@ -222,6 +221,9 @@ static inline int get_boot_cpu_id(void)
 #define get_cpu()		({ preempt_disable(); __smp_processor_id(); })
 #define put_cpu()		preempt_enable()
 
+#define get_cpu_light()		({ migrate_disable(); __smp_processor_id(); })
+#define put_cpu_light()		migrate_enable()
+
 /*
  * Callback to arch code if there's nosmp or maxcpus=0 on the
  * boot command line:
Index: linux-5.4.5-rt3/include/linux/spinlock.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/spinlock.h
+++ linux-5.4.5-rt3/include/linux/spinlock.h
@@ -307,7 +307,11 @@ static inline void do_raw_spin_unlock(ra
 })
 
 /* Include rwlock functions */
-#include <linux/rwlock.h>
+#ifdef CONFIG_PREEMPT_RT
+# include <linux/rwlock_rt.h>
+#else
+# include <linux/rwlock.h>
+#endif
 
 /*
  * Pull the _spin_*()/_read_*()/_write_*() functions/declarations:
@@ -318,6 +322,10 @@ static inline void do_raw_spin_unlock(ra
 # include <linux/spinlock_api_up.h>
 #endif
 
+#ifdef CONFIG_PREEMPT_RT
+# include <linux/spinlock_rt.h>
+#else /* PREEMPT_RT */
+
 /*
  * Map the spin_lock functions to the raw variants for PREEMPT_RT=n
  */
@@ -438,6 +446,8 @@ static __always_inline int spin_is_conte
 
 #define assert_spin_locked(lock)	assert_raw_spin_locked(&(lock)->rlock)
 
+#endif /* !PREEMPT_RT */
+
 /*
  * Pull the atomic_t declaration:
  * (asm-mips/atomic.h needs above definitions)
Index: linux-5.4.5-rt3/include/linux/spinlock_api_smp.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/spinlock_api_smp.h
+++ linux-5.4.5-rt3/include/linux/spinlock_api_smp.h
@@ -187,6 +187,8 @@ static inline int __raw_spin_trylock_bh(
 	return 0;
 }
 
-#include <linux/rwlock_api_smp.h>
+#ifndef CONFIG_PREEMPT_RT
+# include <linux/rwlock_api_smp.h>
+#endif
 
 #endif /* __LINUX_SPINLOCK_API_SMP_H */
Index: linux-5.4.5-rt3/include/linux/spinlock_rt.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/spinlock_rt.h
@@ -0,0 +1,156 @@
+#ifndef __LINUX_SPINLOCK_RT_H
+#define __LINUX_SPINLOCK_RT_H
+
+#ifndef __LINUX_SPINLOCK_H
+#error Do not include directly. Use spinlock.h
+#endif
+
+#include <linux/bug.h>
+
+extern void
+__rt_spin_lock_init(spinlock_t *lock, const char *name, struct lock_class_key *key);
+
+#define spin_lock_init(slock)				\
+do {							\
+	static struct lock_class_key __key;		\
+							\
+	rt_mutex_init(&(slock)->lock);			\
+	__rt_spin_lock_init(slock, #slock, &__key);	\
+} while (0)
+
+extern void __lockfunc rt_spin_lock(spinlock_t *lock);
+extern unsigned long __lockfunc rt_spin_lock_trace_flags(spinlock_t *lock);
+extern void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass);
+extern void __lockfunc rt_spin_unlock(spinlock_t *lock);
+extern void __lockfunc rt_spin_unlock_wait(spinlock_t *lock);
+extern int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags);
+extern int __lockfunc rt_spin_trylock_bh(spinlock_t *lock);
+extern int __lockfunc rt_spin_trylock(spinlock_t *lock);
+extern int atomic_dec_and_spin_lock(atomic_t *atomic, spinlock_t *lock);
+
+/*
+ * lockdep-less calls, for derived types like rwlock:
+ * (for trylock they can use rt_mutex_trylock() directly.
+ * Migrate disable handling must be done at the call site.
+ */
+extern void __lockfunc __rt_spin_lock(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_trylock(struct rt_mutex *lock);
+extern void __lockfunc __rt_spin_unlock(struct rt_mutex *lock);
+
+#define spin_lock(lock)			rt_spin_lock(lock)
+
+#define spin_lock_bh(lock)			\
+	do {					\
+		local_bh_disable();		\
+		rt_spin_lock(lock);		\
+	} while (0)
+
+#define spin_lock_irq(lock)		spin_lock(lock)
+
+#define spin_do_trylock(lock)		__cond_lock(lock, rt_spin_trylock(lock))
+
+#define spin_trylock(lock)			\
+({						\
+	int __locked;				\
+	__locked = spin_do_trylock(lock);	\
+	__locked;				\
+})
+
+#ifdef CONFIG_LOCKDEP
+# define spin_lock_nested(lock, subclass)		\
+	do {						\
+		rt_spin_lock_nested(lock, subclass);	\
+	} while (0)
+
+#define spin_lock_bh_nested(lock, subclass)		\
+	do {						\
+		local_bh_disable();			\
+		rt_spin_lock_nested(lock, subclass);	\
+	} while (0)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		rt_spin_lock_nested(lock, subclass);	 \
+	} while (0)
+#else
+# define spin_lock_nested(lock, subclass)	spin_lock(lock)
+# define spin_lock_bh_nested(lock, subclass)	spin_lock_bh(lock)
+
+# define spin_lock_irqsave_nested(lock, flags, subclass) \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		spin_lock(lock);			 \
+	} while (0)
+#endif
+
+#define spin_lock_irqsave(lock, flags)			 \
+	do {						 \
+		typecheck(unsigned long, flags);	 \
+		flags = 0;				 \
+		spin_lock(lock);			 \
+	} while (0)
+
+static inline unsigned long spin_lock_trace_flags(spinlock_t *lock)
+{
+	unsigned long flags = 0;
+#ifdef CONFIG_TRACE_IRQFLAGS
+	flags = rt_spin_lock_trace_flags(lock);
+#else
+	spin_lock(lock); /* lock_local */
+#endif
+	return flags;
+}
+
+/* FIXME: we need rt_spin_lock_nest_lock */
+#define spin_lock_nest_lock(lock, nest_lock) spin_lock_nested(lock, 0)
+
+#define spin_unlock(lock)			rt_spin_unlock(lock)
+
+#define spin_unlock_bh(lock)				\
+	do {						\
+		rt_spin_unlock(lock);			\
+		local_bh_enable();			\
+	} while (0)
+
+#define spin_unlock_irq(lock)		spin_unlock(lock)
+
+#define spin_unlock_irqrestore(lock, flags)		\
+	do {						\
+		typecheck(unsigned long, flags);	\
+		(void) flags;				\
+		spin_unlock(lock);			\
+	} while (0)
+
+#define spin_trylock_bh(lock)	__cond_lock(lock, rt_spin_trylock_bh(lock))
+#define spin_trylock_irq(lock)	spin_trylock(lock)
+
+#define spin_trylock_irqsave(lock, flags)	\
+	rt_spin_trylock_irqsave(lock, &(flags))
+
+#define spin_unlock_wait(lock)		rt_spin_unlock_wait(lock)
+
+#ifdef CONFIG_GENERIC_LOCKBREAK
+# define spin_is_contended(lock)	((lock)->break_lock)
+#else
+# define spin_is_contended(lock)	(((void)(lock), 0))
+#endif
+
+static inline int spin_can_lock(spinlock_t *lock)
+{
+	return !rt_mutex_is_locked(&lock->lock);
+}
+
+static inline int spin_is_locked(spinlock_t *lock)
+{
+	return rt_mutex_is_locked(&lock->lock);
+}
+
+static inline void assert_spin_locked(spinlock_t *lock)
+{
+	BUG_ON(!spin_is_locked(lock));
+}
+
+#endif
Index: linux-5.4.5-rt3/include/linux/spinlock_types.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/spinlock_types.h
+++ linux-5.4.5-rt3/include/linux/spinlock_types.h
@@ -9,77 +9,15 @@
  * Released under the General Public License (GPL).
  */
 
-#if defined(CONFIG_SMP)
-# include <asm/spinlock_types.h>
-#else
-# include <linux/spinlock_types_up.h>
-#endif
-
-#include <linux/lockdep.h>
-
-typedef struct raw_spinlock {
-	arch_spinlock_t raw_lock;
-#ifdef CONFIG_DEBUG_SPINLOCK
-	unsigned int magic, owner_cpu;
-	void *owner;
-#endif
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-	struct lockdep_map dep_map;
-#endif
-} raw_spinlock_t;
-
-#define SPINLOCK_MAGIC		0xdead4ead
-
-#define SPINLOCK_OWNER_INIT	((void *)-1L)
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define SPIN_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
-#else
-# define SPIN_DEP_MAP_INIT(lockname)
-#endif
+#include <linux/spinlock_types_raw.h>
 
-#ifdef CONFIG_DEBUG_SPINLOCK
-# define SPIN_DEBUG_INIT(lockname)		\
-	.magic = SPINLOCK_MAGIC,		\
-	.owner_cpu = -1,			\
-	.owner = SPINLOCK_OWNER_INIT,
+#ifndef CONFIG_PREEMPT_RT
+# include <linux/spinlock_types_nort.h>
+# include <linux/rwlock_types.h>
 #else
-# define SPIN_DEBUG_INIT(lockname)
+# include <linux/rtmutex.h>
+# include <linux/spinlock_types_rt.h>
+# include <linux/rwlock_types_rt.h>
 #endif
 
-#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
-	{					\
-	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
-	SPIN_DEBUG_INIT(lockname)		\
-	SPIN_DEP_MAP_INIT(lockname) }
-
-#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
-	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
-
-#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
-
-typedef struct spinlock {
-	union {
-		struct raw_spinlock rlock;
-
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
-		struct {
-			u8 __padding[LOCK_PADSIZE];
-			struct lockdep_map dep_map;
-		};
-#endif
-	};
-} spinlock_t;
-
-#define __SPIN_LOCK_INITIALIZER(lockname) \
-	{ { .rlock = __RAW_SPIN_LOCK_INITIALIZER(lockname) } }
-
-#define __SPIN_LOCK_UNLOCKED(lockname) \
-	(spinlock_t ) __SPIN_LOCK_INITIALIZER(lockname)
-
-#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
-
-#include <linux/rwlock_types.h>
-
 #endif /* __LINUX_SPINLOCK_TYPES_H */
Index: linux-5.4.5-rt3/include/linux/spinlock_types_nort.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/spinlock_types_nort.h
@@ -0,0 +1,33 @@
+#ifndef __LINUX_SPINLOCK_TYPES_NORT_H
+#define __LINUX_SPINLOCK_TYPES_NORT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+/*
+ * The non RT version maps spinlocks to raw_spinlocks
+ */
+typedef struct spinlock {
+	union {
+		struct raw_spinlock rlock;
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define LOCK_PADSIZE (offsetof(struct raw_spinlock, dep_map))
+		struct {
+			u8 __padding[LOCK_PADSIZE];
+			struct lockdep_map dep_map;
+		};
+#endif
+	};
+} spinlock_t;
+
+#define __SPIN_LOCK_INITIALIZER(lockname) \
+	{ { .rlock = __RAW_SPIN_LOCK_INITIALIZER(lockname) } }
+
+#define __SPIN_LOCK_UNLOCKED(lockname) \
+	(spinlock_t ) __SPIN_LOCK_INITIALIZER(lockname)
+
+#define DEFINE_SPINLOCK(x)	spinlock_t x = __SPIN_LOCK_UNLOCKED(x)
+
+#endif
Index: linux-5.4.5-rt3/include/linux/spinlock_types_raw.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/spinlock_types_raw.h
@@ -0,0 +1,55 @@
+#ifndef __LINUX_SPINLOCK_TYPES_RAW_H
+#define __LINUX_SPINLOCK_TYPES_RAW_H
+
+#include <linux/types.h>
+
+#if defined(CONFIG_SMP)
+# include <asm/spinlock_types.h>
+#else
+# include <linux/spinlock_types_up.h>
+#endif
+
+#include <linux/lockdep.h>
+
+typedef struct raw_spinlock {
+	arch_spinlock_t raw_lock;
+#ifdef CONFIG_DEBUG_SPINLOCK
+	unsigned int magic, owner_cpu;
+	void *owner;
+#endif
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map dep_map;
+#endif
+} raw_spinlock_t;
+
+#define SPINLOCK_MAGIC		0xdead4ead
+
+#define SPINLOCK_OWNER_INIT	((void *)-1L)
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+# define SPIN_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname }
+#else
+# define SPIN_DEP_MAP_INIT(lockname)
+#endif
+
+#ifdef CONFIG_DEBUG_SPINLOCK
+# define SPIN_DEBUG_INIT(lockname)		\
+	.magic = SPINLOCK_MAGIC,		\
+	.owner_cpu = -1,			\
+	.owner = SPINLOCK_OWNER_INIT,
+#else
+# define SPIN_DEBUG_INIT(lockname)
+#endif
+
+#define __RAW_SPIN_LOCK_INITIALIZER(lockname)	\
+	{					\
+	.raw_lock = __ARCH_SPIN_LOCK_UNLOCKED,	\
+	SPIN_DEBUG_INIT(lockname)		\
+	SPIN_DEP_MAP_INIT(lockname) }
+
+#define __RAW_SPIN_LOCK_UNLOCKED(lockname)	\
+	(raw_spinlock_t) __RAW_SPIN_LOCK_INITIALIZER(lockname)
+
+#define DEFINE_RAW_SPINLOCK(x)	raw_spinlock_t x = __RAW_SPIN_LOCK_UNLOCKED(x)
+
+#endif
Index: linux-5.4.5-rt3/include/linux/spinlock_types_rt.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/linux/spinlock_types_rt.h
@@ -0,0 +1,48 @@
+#ifndef __LINUX_SPINLOCK_TYPES_RT_H
+#define __LINUX_SPINLOCK_TYPES_RT_H
+
+#ifndef __LINUX_SPINLOCK_TYPES_H
+#error "Do not include directly. Include spinlock_types.h instead"
+#endif
+
+#include <linux/cache.h>
+
+/*
+ * PREEMPT_RT: spinlocks - an RT mutex plus lock-break field:
+ */
+typedef struct spinlock {
+	struct rt_mutex		lock;
+	unsigned int		break_lock;
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	struct lockdep_map	dep_map;
+#endif
+} spinlock_t;
+
+#ifdef CONFIG_DEBUG_RT_MUTEXES
+# define __RT_SPIN_INITIALIZER(name) \
+	{ \
+	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock), \
+	.save_state = 1, \
+	.file = __FILE__, \
+	.line = __LINE__ , \
+	}
+#else
+# define __RT_SPIN_INITIALIZER(name) \
+	{								\
+	.wait_lock = __RAW_SPIN_LOCK_UNLOCKED(name.wait_lock),		\
+	.save_state = 1, \
+	}
+#endif
+
+/*
+.wait_list = PLIST_HEAD_INIT_RAW((name).lock.wait_list, (name).lock.wait_lock)
+*/
+
+#define __SPIN_LOCK_UNLOCKED(name)			\
+	{ .lock = __RT_SPIN_INITIALIZER(name.lock),		\
+	  SPIN_DEP_MAP_INIT(name) }
+
+#define DEFINE_SPINLOCK(name) \
+	spinlock_t name = __SPIN_LOCK_UNLOCKED(name)
+
+#endif
Index: linux-5.4.5-rt3/include/linux/spinlock_types_up.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/spinlock_types_up.h
+++ linux-5.4.5-rt3/include/linux/spinlock_types_up.h
@@ -1,10 +1,6 @@
 #ifndef __LINUX_SPINLOCK_TYPES_UP_H
 #define __LINUX_SPINLOCK_TYPES_UP_H
 
-#ifndef __LINUX_SPINLOCK_TYPES_H
-# error "please don't include this file directly"
-#endif
-
 /*
  * include/linux/spinlock_types_up.h - spinlock type definitions for UP
  *
Index: linux-5.4.5-rt3/include/linux/stop_machine.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/stop_machine.h
+++ linux-5.4.5-rt3/include/linux/stop_machine.h
@@ -26,6 +26,8 @@ struct cpu_stop_work {
 	cpu_stop_fn_t		fn;
 	void			*arg;
 	struct cpu_stop_done	*done;
+	/* Did not run due to disabled stopper; for nowait debug checks */
+	bool			disabled;
 };
 
 int stop_one_cpu(unsigned int cpu, cpu_stop_fn_t fn, void *arg);
Index: linux-5.4.5-rt3/include/linux/suspend.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/suspend.h
+++ linux-5.4.5-rt3/include/linux/suspend.h
@@ -197,6 +197,12 @@ struct platform_s2idle_ops {
 	void (*end)(void);
 };
 
+#if defined(CONFIG_SUSPEND) || defined(CONFIG_HIBERNATION)
+extern bool pm_in_action;
+#else
+# define pm_in_action false
+#endif
+
 #ifdef CONFIG_SUSPEND
 extern suspend_state_t mem_sleep_current;
 extern suspend_state_t mem_sleep_default;
Index: linux-5.4.5-rt3/include/linux/swait.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/swait.h
+++ linux-5.4.5-rt3/include/linux/swait.h
@@ -160,7 +160,9 @@ static inline bool swq_has_sleeper(struc
 extern void swake_up_one(struct swait_queue_head *q);
 extern void swake_up_all(struct swait_queue_head *q);
 extern void swake_up_locked(struct swait_queue_head *q);
+extern void swake_up_all_locked(struct swait_queue_head *q);
 
+extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
 extern void prepare_to_swait_exclusive(struct swait_queue_head *q, struct swait_queue *wait, int state);
 extern long prepare_to_swait_event(struct swait_queue_head *q, struct swait_queue *wait, int state);
 
@@ -297,4 +299,18 @@ do {									\
 	__ret;								\
 })
 
+#define __swait_event_lock_irq(wq, condition, lock, cmd)		\
+	___swait_event(wq, condition, TASK_UNINTERRUPTIBLE, 0,		\
+		       raw_spin_unlock_irq(&lock);			\
+		       cmd;						\
+		       schedule();					\
+		       raw_spin_lock_irq(&lock))
+
+#define swait_event_lock_irq(wq_head, condition, lock)			\
+	do {								\
+		if (condition)						\
+			break;						\
+		__swait_event_lock_irq(wq_head, condition, lock, );	\
+	} while (0)
+
 #endif /* _LINUX_SWAIT_H */
Index: linux-5.4.5-rt3/include/linux/thread_info.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/thread_info.h
+++ linux-5.4.5-rt3/include/linux/thread_info.h
@@ -97,7 +97,17 @@ static inline int test_ti_thread_flag(st
 #define test_thread_flag(flag) \
 	test_ti_thread_flag(current_thread_info(), flag)
 
-#define tif_need_resched() test_thread_flag(TIF_NEED_RESCHED)
+#ifdef CONFIG_PREEMPT_LAZY
+#define tif_need_resched()	(test_thread_flag(TIF_NEED_RESCHED) || \
+				 test_thread_flag(TIF_NEED_RESCHED_LAZY))
+#define tif_need_resched_now()	(test_thread_flag(TIF_NEED_RESCHED))
+#define tif_need_resched_lazy()	test_thread_flag(TIF_NEED_RESCHED_LAZY))
+
+#else
+#define tif_need_resched()	test_thread_flag(TIF_NEED_RESCHED)
+#define tif_need_resched_now()	test_thread_flag(TIF_NEED_RESCHED)
+#define tif_need_resched_lazy()	0
+#endif
 
 #ifndef CONFIG_HAVE_ARCH_WITHIN_STACK_FRAMES
 static inline int arch_within_stack_frames(const void * const stack,
Index: linux-5.4.5-rt3/include/linux/trace_events.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/trace_events.h
+++ linux-5.4.5-rt3/include/linux/trace_events.h
@@ -62,6 +62,9 @@ struct trace_entry {
 	unsigned char		flags;
 	unsigned char		preempt_count;
 	int			pid;
+	unsigned short		migrate_disable;
+	unsigned short		padding;
+	unsigned char		preempt_lazy_count;
 };
 
 #define TRACE_EVENT_TYPE_MAX						\
Index: linux-5.4.5-rt3/include/linux/uaccess.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/uaccess.h
+++ linux-5.4.5-rt3/include/linux/uaccess.h
@@ -182,6 +182,7 @@ static __always_inline void pagefault_di
  */
 static inline void pagefault_disable(void)
 {
+	migrate_disable();
 	pagefault_disabled_inc();
 	/*
 	 * make sure to have issued the store before a pagefault
@@ -198,6 +199,7 @@ static inline void pagefault_enable(void
 	 */
 	barrier();
 	pagefault_disabled_dec();
+	migrate_enable();
 }
 
 /*
Index: linux-5.4.5-rt3/include/linux/vmstat.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/vmstat.h
+++ linux-5.4.5-rt3/include/linux/vmstat.h
@@ -54,7 +54,9 @@ DECLARE_PER_CPU(struct vm_event_state, v
  */
 static inline void __count_vm_event(enum vm_event_item item)
 {
+	preempt_disable_rt();
 	raw_cpu_inc(vm_event_states.event[item]);
+	preempt_enable_rt();
 }
 
 static inline void count_vm_event(enum vm_event_item item)
@@ -64,7 +66,9 @@ static inline void count_vm_event(enum v
 
 static inline void __count_vm_events(enum vm_event_item item, long delta)
 {
+	preempt_disable_rt();
 	raw_cpu_add(vm_event_states.event[item], delta);
+	preempt_enable_rt();
 }
 
 static inline void count_vm_events(enum vm_event_item item, long delta)
Index: linux-5.4.5-rt3/include/linux/wait.h
===================================================================
--- linux-5.4.5-rt3.orig/include/linux/wait.h
+++ linux-5.4.5-rt3/include/linux/wait.h
@@ -10,6 +10,7 @@
 
 #include <asm/current.h>
 #include <uapi/linux/wait.h>
+#include <linux/atomic.h>
 
 typedef struct wait_queue_entry wait_queue_entry_t;
 
@@ -20,6 +21,7 @@ int default_wake_function(struct wait_qu
 #define WQ_FLAG_EXCLUSIVE	0x01
 #define WQ_FLAG_WOKEN		0x02
 #define WQ_FLAG_BOOKMARK	0x04
+#define WQ_FLAG_CUSTOM		0x08
 
 /*
  * A single wait-queue entry structure:
Index: linux-5.4.5-rt3/include/net/gen_stats.h
===================================================================
--- linux-5.4.5-rt3.orig/include/net/gen_stats.h
+++ linux-5.4.5-rt3/include/net/gen_stats.h
@@ -6,6 +6,7 @@
 #include <linux/socket.h>
 #include <linux/rtnetlink.h>
 #include <linux/pkt_sched.h>
+#include <net/net_seq_lock.h>
 
 struct gnet_stats_basic_cpu {
 	struct gnet_stats_basic_packed bstats;
@@ -36,15 +37,15 @@ int gnet_stats_start_copy_compat(struct
 				 spinlock_t *lock, struct gnet_dump *d,
 				 int padattr);
 
-int gnet_stats_copy_basic(const seqcount_t *running,
+int gnet_stats_copy_basic(net_seqlock_t *running,
 			  struct gnet_dump *d,
 			  struct gnet_stats_basic_cpu __percpu *cpu,
 			  struct gnet_stats_basic_packed *b);
-void __gnet_stats_copy_basic(const seqcount_t *running,
+void __gnet_stats_copy_basic(net_seqlock_t *running,
 			     struct gnet_stats_basic_packed *bstats,
 			     struct gnet_stats_basic_cpu __percpu *cpu,
 			     struct gnet_stats_basic_packed *b);
-int gnet_stats_copy_basic_hw(const seqcount_t *running,
+int gnet_stats_copy_basic_hw(net_seqlock_t *running,
 			     struct gnet_dump *d,
 			     struct gnet_stats_basic_cpu __percpu *cpu,
 			     struct gnet_stats_basic_packed *b);
@@ -64,13 +65,13 @@ int gen_new_estimator(struct gnet_stats_
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
 		      spinlock_t *lock,
-		      seqcount_t *running, struct nlattr *opt);
+		      net_seqlock_t *running, struct nlattr *opt);
 void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
 int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **ptr,
 			  spinlock_t *lock,
-			  seqcount_t *running, struct nlattr *opt);
+			  net_seqlock_t *running, struct nlattr *opt);
 bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
 bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
 			struct gnet_stats_rate_est64 *sample);
Index: linux-5.4.5-rt3/include/net/neighbour.h
===================================================================
--- linux-5.4.5-rt3.orig/include/net/neighbour.h
+++ linux-5.4.5-rt3/include/net/neighbour.h
@@ -459,7 +459,7 @@ static inline int neigh_hh_bridge(struct
 }
 #endif
 
-static inline int neigh_hh_output(const struct hh_cache *hh, struct sk_buff *skb)
+static inline int neigh_hh_output(struct hh_cache *hh, struct sk_buff *skb)
 {
 	unsigned int hh_alen = 0;
 	unsigned int seq;
@@ -502,7 +502,7 @@ static inline int neigh_hh_output(const
 static inline int neigh_output(struct neighbour *n, struct sk_buff *skb,
 			       bool skip_cache)
 {
-	const struct hh_cache *hh = &n->hh;
+	struct hh_cache *hh = &n->hh;
 
 	if ((n->nud_state & NUD_CONNECTED) && hh->hh_len && !skip_cache)
 		return neigh_hh_output(hh, skb);
@@ -543,7 +543,7 @@ struct neighbour_cb {
 
 #define NEIGH_CB(skb)	((struct neighbour_cb *)(skb)->cb)
 
-static inline void neigh_ha_snapshot(char *dst, const struct neighbour *n,
+static inline void neigh_ha_snapshot(char *dst, struct neighbour *n,
 				     const struct net_device *dev)
 {
 	unsigned int seq;
Index: linux-5.4.5-rt3/include/net/net_seq_lock.h
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/include/net/net_seq_lock.h
@@ -0,0 +1,15 @@
+#ifndef __NET_NET_SEQ_LOCK_H__
+#define __NET_NET_SEQ_LOCK_H__
+
+#ifdef CONFIG_PREEMPT_RT
+# define net_seqlock_t			seqlock_t
+# define net_seq_begin(__r)		read_seqbegin(__r)
+# define net_seq_retry(__r, __s)	read_seqretry(__r, __s)
+
+#else
+# define net_seqlock_t			seqcount_t
+# define net_seq_begin(__r)		read_seqcount_begin(__r)
+# define net_seq_retry(__r, __s)	read_seqcount_retry(__r, __s)
+#endif
+
+#endif
Index: linux-5.4.5-rt3/include/net/sch_generic.h
===================================================================
--- linux-5.4.5-rt3.orig/include/net/sch_generic.h
+++ linux-5.4.5-rt3/include/net/sch_generic.h
@@ -10,6 +10,7 @@
 #include <linux/percpu.h>
 #include <linux/dynamic_queue_limits.h>
 #include <linux/list.h>
+#include <net/net_seq_lock.h>
 #include <linux/refcount.h>
 #include <linux/workqueue.h>
 #include <linux/mutex.h>
@@ -100,7 +101,7 @@ struct Qdisc {
 	struct sk_buff_head	gso_skb ____cacheline_aligned_in_smp;
 	struct qdisc_skb_head	q;
 	struct gnet_stats_basic_packed bstats;
-	seqcount_t		running;
+	net_seqlock_t		running;
 	struct gnet_stats_queue	qstats;
 	unsigned long		state;
 	struct Qdisc            *next_sched;
@@ -138,7 +139,11 @@ static inline bool qdisc_is_running(stru
 {
 	if (qdisc->flags & TCQ_F_NOLOCK)
 		return spin_is_locked(&qdisc->seqlock);
+#ifdef CONFIG_PREEMPT_RT
+	return spin_is_locked(&qdisc->running.lock) ? true : false;
+#else
 	return (raw_read_seqcount(&qdisc->running) & 1) ? true : false;
+#endif
 }
 
 static inline bool qdisc_is_percpu_stats(const struct Qdisc *q)
@@ -162,17 +167,27 @@ static inline bool qdisc_run_begin(struc
 	} else if (qdisc_is_running(qdisc)) {
 		return false;
 	}
+#ifdef CONFIG_PREEMPT_RT
+	if (try_write_seqlock(&qdisc->running))
+		return true;
+	return false;
+#else
 	/* Variant of write_seqcount_begin() telling lockdep a trylock
 	 * was attempted.
 	 */
 	raw_write_seqcount_begin(&qdisc->running);
 	seqcount_acquire(&qdisc->running.dep_map, 0, 1, _RET_IP_);
 	return true;
+#endif
 }
 
 static inline void qdisc_run_end(struct Qdisc *qdisc)
 {
+#ifdef CONFIG_PREEMPT_RT
+	write_sequnlock(&qdisc->running);
+#else
 	write_seqcount_end(&qdisc->running);
+#endif
 	if (qdisc->flags & TCQ_F_NOLOCK)
 		spin_unlock(&qdisc->seqlock);
 }
@@ -541,7 +556,7 @@ static inline spinlock_t *qdisc_root_sle
 	return qdisc_lock(root);
 }
 
-static inline seqcount_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
+static inline net_seqlock_t *qdisc_root_sleeping_running(const struct Qdisc *qdisc)
 {
 	struct Qdisc *root = qdisc_root_sleeping(qdisc);
 
Index: linux-5.4.5-rt3/include/xen/xen-ops.h
===================================================================
--- linux-5.4.5-rt3.orig/include/xen/xen-ops.h
+++ linux-5.4.5-rt3/include/xen/xen-ops.h
@@ -215,7 +215,7 @@ bool xen_running_on_version_or_later(uns
 void xen_efi_runtime_setup(void);
 
 
-#ifdef CONFIG_PREEMPT
+#ifdef CONFIG_PREEMPTION
 
 static inline void xen_preemptible_hcall_begin(void)
 {
@@ -239,6 +239,6 @@ static inline void xen_preemptible_hcall
 	__this_cpu_write(xen_in_preemptible_hcall, false);
 }
 
-#endif /* CONFIG_PREEMPT */
+#endif /* CONFIG_PREEMPTION */
 
 #endif /* INCLUDE_XEN_OPS_H */
Index: linux-5.4.5-rt3/init/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/init/Kconfig
+++ linux-5.4.5-rt3/init/Kconfig
@@ -924,6 +924,7 @@ config CFS_BANDWIDTH
 config RT_GROUP_SCHED
 	bool "Group scheduling for SCHED_RR/FIFO"
 	depends on CGROUP_SCHED
+	depends on !PREEMPT_RT
 	default n
 	help
 	  This feature lets you explicitly allocate real CPU bandwidth
@@ -1630,6 +1631,7 @@ config KALLSYMS_BASE_RELATIVE
 # syscall, maps, verifier
 config BPF_SYSCALL
 	bool "Enable bpf() system call"
+	depends on !PREEMPT_RT
 	select BPF
 	select IRQ_WORK
 	default n
@@ -1805,6 +1807,7 @@ choice
 
 config SLAB
 	bool "SLAB"
+	depends on !PREEMPT_RT
 	select HAVE_HARDENED_USERCOPY_ALLOCATOR
 	help
 	  The regular slab allocator that is established and known to work
@@ -1825,6 +1828,7 @@ config SLUB
 config SLOB
 	depends on EXPERT
 	bool "SLOB (Simple Allocator)"
+	depends on !PREEMPT_RT
 	help
 	   SLOB replaces the stock allocator with a drastically simpler
 	   allocator. SLOB is generally more space efficient but
@@ -1890,7 +1894,7 @@ config SHUFFLE_PAGE_ALLOCATOR
 
 config SLUB_CPU_PARTIAL
 	default y
-	depends on SLUB && SMP
+	depends on SLUB && SMP && !PREEMPT_RT
 	bool "SLUB per cpu partial cache"
 	help
 	  Per cpu partial caches accelerate objects allocation and freeing
Index: linux-5.4.5-rt3/init/init_task.c
===================================================================
--- linux-5.4.5-rt3.orig/init/init_task.c
+++ linux-5.4.5-rt3/init/init_task.c
@@ -73,6 +73,10 @@ struct task_struct init_task
 	.cpus_ptr	= &init_task.cpus_mask,
 	.cpus_mask	= CPU_MASK_ALL,
 	.nr_cpus_allowed= NR_CPUS,
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT) && \
+    defined(CONFIG_SCHED_DEBUG)
+	.pinned_on_cpu	= -1,
+#endif
 	.mm		= NULL,
 	.active_mm	= &init_mm,
 	.restart_block	= {
Index: linux-5.4.5-rt3/init/main.c
===================================================================
--- linux-5.4.5-rt3.orig/init/main.c
+++ linux-5.4.5-rt3/init/main.c
@@ -694,7 +694,6 @@ asmlinkage __visible void __init start_k
 	boot_init_stack_canary();
 
 	time_init();
-	printk_safe_init();
 	perf_event_init();
 	profile_init();
 	call_function_init();
Index: linux-5.4.5-rt3/kernel/Kconfig.locks
===================================================================
--- linux-5.4.5-rt3.orig/kernel/Kconfig.locks
+++ linux-5.4.5-rt3/kernel/Kconfig.locks
@@ -101,7 +101,7 @@ config UNINLINE_SPIN_UNLOCK
 # unlock and unlock_irq functions are inlined when:
 #   - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
 #  or
-#   - DEBUG_SPINLOCK=n and PREEMPT=n
+#   - DEBUG_SPINLOCK=n and PREEMPTION=n
 #
 # unlock_bh and unlock_irqrestore functions are inlined when:
 #   - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
@@ -139,7 +139,7 @@ config INLINE_SPIN_UNLOCK_BH
 
 config INLINE_SPIN_UNLOCK_IRQ
 	def_bool y
-	depends on !PREEMPT || ARCH_INLINE_SPIN_UNLOCK_IRQ
+	depends on !PREEMPTION || ARCH_INLINE_SPIN_UNLOCK_IRQ
 
 config INLINE_SPIN_UNLOCK_IRQRESTORE
 	def_bool y
@@ -168,7 +168,7 @@ config INLINE_READ_LOCK_IRQSAVE
 
 config INLINE_READ_UNLOCK
 	def_bool y
-	depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK
+	depends on !PREEMPTION || ARCH_INLINE_READ_UNLOCK
 
 config INLINE_READ_UNLOCK_BH
 	def_bool y
@@ -176,7 +176,7 @@ config INLINE_READ_UNLOCK_BH
 
 config INLINE_READ_UNLOCK_IRQ
 	def_bool y
-	depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK_IRQ
+	depends on !PREEMPTION || ARCH_INLINE_READ_UNLOCK_IRQ
 
 config INLINE_READ_UNLOCK_IRQRESTORE
 	def_bool y
@@ -205,7 +205,7 @@ config INLINE_WRITE_LOCK_IRQSAVE
 
 config INLINE_WRITE_UNLOCK
 	def_bool y
-	depends on !PREEMPT || ARCH_INLINE_WRITE_UNLOCK
+	depends on !PREEMPTION || ARCH_INLINE_WRITE_UNLOCK
 
 config INLINE_WRITE_UNLOCK_BH
 	def_bool y
@@ -213,7 +213,7 @@ config INLINE_WRITE_UNLOCK_BH
 
 config INLINE_WRITE_UNLOCK_IRQ
 	def_bool y
-	depends on !PREEMPT || ARCH_INLINE_WRITE_UNLOCK_IRQ
+	depends on !PREEMPTION || ARCH_INLINE_WRITE_UNLOCK_IRQ
 
 config INLINE_WRITE_UNLOCK_IRQRESTORE
 	def_bool y
Index: linux-5.4.5-rt3/kernel/Kconfig.preempt
===================================================================
--- linux-5.4.5-rt3.orig/kernel/Kconfig.preempt
+++ linux-5.4.5-rt3/kernel/Kconfig.preempt
@@ -1,5 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
+config HAVE_PREEMPT_LAZY
+	bool
+
+config PREEMPT_LAZY
+	def_bool y if HAVE_PREEMPT_LAZY && PREEMPT_RT
+
 choice
 	prompt "Preemption Model"
 	default PREEMPT_NONE
Index: linux-5.4.5-rt3/kernel/cgroup/cgroup.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/cgroup/cgroup.c
+++ linux-5.4.5-rt3/kernel/cgroup/cgroup.c
@@ -1957,7 +1957,6 @@ static void init_cgroup_housekeeping(str
 	cgrp->dom_cgrp = cgrp;
 	cgrp->max_descendants = INT_MAX;
 	cgrp->max_depth = INT_MAX;
-	INIT_LIST_HEAD(&cgrp->rstat_css_list);
 	prev_cputime_init(&cgrp->prev_cputime);
 
 	for_each_subsys(ss, ssid)
@@ -5013,12 +5012,6 @@ static void css_release_work_fn(struct w
 	list_del_rcu(&css->sibling);
 
 	if (ss) {
-		/* css release path */
-		if (!list_empty(&css->rstat_css_node)) {
-			cgroup_rstat_flush(cgrp);
-			list_del_rcu(&css->rstat_css_node);
-		}
-
 		cgroup_idr_replace(&ss->css_idr, NULL, css->id);
 		if (ss->css_released)
 			ss->css_released(css);
@@ -5080,7 +5073,6 @@ static void init_and_link_css(struct cgr
 	css->id = -1;
 	INIT_LIST_HEAD(&css->sibling);
 	INIT_LIST_HEAD(&css->children);
-	INIT_LIST_HEAD(&css->rstat_css_node);
 	css->serial_nr = css_serial_nr_next++;
 	atomic_set(&css->online_cnt, 0);
 
@@ -5089,9 +5081,6 @@ static void init_and_link_css(struct cgr
 		css_get(css->parent);
 	}
 
-	if (cgroup_on_dfl(cgrp) && ss->css_rstat_flush)
-		list_add_rcu(&css->rstat_css_node, &cgrp->rstat_css_list);
-
 	BUG_ON(cgroup_css(cgrp, ss));
 }
 
@@ -5193,7 +5182,6 @@ static struct cgroup_subsys_state *css_c
 err_list_del:
 	list_del_rcu(&css->sibling);
 err_free_css:
-	list_del_rcu(&css->rstat_css_node);
 	INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
 	queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
 	return ERR_PTR(err);
Index: linux-5.4.5-rt3/kernel/cgroup/cpuset.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/cgroup/cpuset.c
+++ linux-5.4.5-rt3/kernel/cgroup/cpuset.c
@@ -345,7 +345,7 @@ void cpuset_read_unlock(void)
 	percpu_up_read(&cpuset_rwsem);
 }
 
-static DEFINE_SPINLOCK(callback_lock);
+static DEFINE_RAW_SPINLOCK(callback_lock);
 
 static struct workqueue_struct *cpuset_migrate_mm_wq;
 
@@ -1255,7 +1255,7 @@ static int update_parent_subparts_cpumas
 	 * Newly added CPUs will be removed from effective_cpus and
 	 * newly deleted ones will be added back to effective_cpus.
 	 */
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	if (adding) {
 		cpumask_or(parent->subparts_cpus,
 			   parent->subparts_cpus, tmp->addmask);
@@ -1274,7 +1274,7 @@ static int update_parent_subparts_cpumas
 	}
 
 	parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	return cmd == partcmd_update;
 }
@@ -1379,7 +1379,7 @@ static void update_cpumasks_hier(struct
 			continue;
 		rcu_read_unlock();
 
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 
 		cpumask_copy(cp->effective_cpus, tmp->new_cpus);
 		if (cp->nr_subparts_cpus &&
@@ -1410,7 +1410,7 @@ static void update_cpumasks_hier(struct
 					= cpumask_weight(cp->subparts_cpus);
 			}
 		}
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 
 		WARN_ON(!is_in_v2_mode() &&
 			!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
@@ -1528,7 +1528,7 @@ static int update_cpumask(struct cpuset
 			return -EINVAL;
 	}
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
 
 	/*
@@ -1539,7 +1539,7 @@ static int update_cpumask(struct cpuset
 			       cs->cpus_allowed);
 		cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
 	}
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	update_cpumasks_hier(cs, &tmp);
 
@@ -1733,9 +1733,9 @@ static void update_nodemasks_hier(struct
 			continue;
 		rcu_read_unlock();
 
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 		cp->effective_mems = *new_mems;
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 
 		WARN_ON(!is_in_v2_mode() &&
 			!nodes_equal(cp->mems_allowed, cp->effective_mems));
@@ -1803,9 +1803,9 @@ static int update_nodemask(struct cpuset
 	if (retval < 0)
 		goto done;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cs->mems_allowed = trialcs->mems_allowed;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	/* use trialcs->mems_allowed as a temp variable */
 	update_nodemasks_hier(cs, &trialcs->mems_allowed);
@@ -1896,9 +1896,9 @@ static int update_flag(cpuset_flagbits_t
 	spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs))
 			|| (is_spread_page(cs) != is_spread_page(trialcs)));
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cs->flags = trialcs->flags;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
 		rebuild_sched_domains_locked();
@@ -2407,7 +2407,7 @@ static int cpuset_common_seq_show(struct
 	cpuset_filetype_t type = seq_cft(sf)->private;
 	int ret = 0;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 
 	switch (type) {
 	case FILE_CPULIST:
@@ -2429,7 +2429,7 @@ static int cpuset_common_seq_show(struct
 		ret = -EINVAL;
 	}
 
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 	return ret;
 }
 
@@ -2742,14 +2742,14 @@ static int cpuset_css_online(struct cgro
 
 	cpuset_inc();
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	if (is_in_v2_mode()) {
 		cpumask_copy(cs->effective_cpus, parent->effective_cpus);
 		cs->effective_mems = parent->effective_mems;
 		cs->use_parent_ecpus = true;
 		parent->child_ecpus_count++;
 	}
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags))
 		goto out_unlock;
@@ -2776,12 +2776,12 @@ static int cpuset_css_online(struct cgro
 	}
 	rcu_read_unlock();
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cs->mems_allowed = parent->mems_allowed;
 	cs->effective_mems = parent->mems_allowed;
 	cpumask_copy(cs->cpus_allowed, parent->cpus_allowed);
 	cpumask_copy(cs->effective_cpus, parent->cpus_allowed);
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
 	put_online_cpus();
@@ -2837,7 +2837,7 @@ static void cpuset_css_free(struct cgrou
 static void cpuset_bind(struct cgroup_subsys_state *root_css)
 {
 	percpu_down_write(&cpuset_rwsem);
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 
 	if (is_in_v2_mode()) {
 		cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask);
@@ -2848,7 +2848,7 @@ static void cpuset_bind(struct cgroup_su
 		top_cpuset.mems_allowed = top_cpuset.effective_mems;
 	}
 
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 	percpu_up_write(&cpuset_rwsem);
 }
 
@@ -2945,12 +2945,12 @@ hotplug_update_tasks_legacy(struct cpuse
 {
 	bool is_empty;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cpumask_copy(cs->cpus_allowed, new_cpus);
 	cpumask_copy(cs->effective_cpus, new_cpus);
 	cs->mems_allowed = *new_mems;
 	cs->effective_mems = *new_mems;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	/*
 	 * Don't call update_tasks_cpumask() if the cpuset becomes empty,
@@ -2987,10 +2987,10 @@ hotplug_update_tasks(struct cpuset *cs,
 	if (nodes_empty(*new_mems))
 		*new_mems = parent_cs(cs)->effective_mems;
 
-	spin_lock_irq(&callback_lock);
+	raw_spin_lock_irq(&callback_lock);
 	cpumask_copy(cs->effective_cpus, new_cpus);
 	cs->effective_mems = *new_mems;
-	spin_unlock_irq(&callback_lock);
+	raw_spin_unlock_irq(&callback_lock);
 
 	if (cpus_updated)
 		update_tasks_cpumask(cs);
@@ -3145,7 +3145,7 @@ static void cpuset_hotplug_workfn(struct
 
 	/* synchronize cpus_allowed to cpu_active_mask */
 	if (cpus_updated) {
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 		if (!on_dfl)
 			cpumask_copy(top_cpuset.cpus_allowed, &new_cpus);
 		/*
@@ -3165,17 +3165,17 @@ static void cpuset_hotplug_workfn(struct
 			}
 		}
 		cpumask_copy(top_cpuset.effective_cpus, &new_cpus);
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 		/* we don't mess with cpumasks of tasks in top_cpuset */
 	}
 
 	/* synchronize mems_allowed to N_MEMORY */
 	if (mems_updated) {
-		spin_lock_irq(&callback_lock);
+		raw_spin_lock_irq(&callback_lock);
 		if (!on_dfl)
 			top_cpuset.mems_allowed = new_mems;
 		top_cpuset.effective_mems = new_mems;
-		spin_unlock_irq(&callback_lock);
+		raw_spin_unlock_irq(&callback_lock);
 		update_tasks_nodemask(&top_cpuset);
 	}
 
@@ -3276,11 +3276,11 @@ void cpuset_cpus_allowed(struct task_str
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&callback_lock, flags);
+	raw_spin_lock_irqsave(&callback_lock, flags);
 	rcu_read_lock();
 	guarantee_online_cpus(task_cs(tsk), pmask);
 	rcu_read_unlock();
-	spin_unlock_irqrestore(&callback_lock, flags);
+	raw_spin_unlock_irqrestore(&callback_lock, flags);
 }
 
 /**
@@ -3341,11 +3341,11 @@ nodemask_t cpuset_mems_allowed(struct ta
 	nodemask_t mask;
 	unsigned long flags;
 
-	spin_lock_irqsave(&callback_lock, flags);
+	raw_spin_lock_irqsave(&callback_lock, flags);
 	rcu_read_lock();
 	guarantee_online_mems(task_cs(tsk), &mask);
 	rcu_read_unlock();
-	spin_unlock_irqrestore(&callback_lock, flags);
+	raw_spin_unlock_irqrestore(&callback_lock, flags);
 
 	return mask;
 }
@@ -3437,14 +3437,14 @@ bool __cpuset_node_allowed(int node, gfp
 		return true;
 
 	/* Not hardwall and node outside mems_allowed: scan up cpusets */
-	spin_lock_irqsave(&callback_lock, flags);
+	raw_spin_lock_irqsave(&callback_lock, flags);
 
 	rcu_read_lock();
 	cs = nearest_hardwall_ancestor(task_cs(current));
 	allowed = node_isset(node, cs->mems_allowed);
 	rcu_read_unlock();
 
-	spin_unlock_irqrestore(&callback_lock, flags);
+	raw_spin_unlock_irqrestore(&callback_lock, flags);
 	return allowed;
 }
 
Index: linux-5.4.5-rt3/kernel/cgroup/rstat.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/cgroup/rstat.c
+++ linux-5.4.5-rt3/kernel/cgroup/rstat.c
@@ -149,7 +149,7 @@ static struct cgroup *cgroup_rstat_cpu_p
 }
 
 /* see cgroup_rstat_flush() */
-static void cgroup_rstat_flush_locked(struct cgroup *cgrp, bool may_sleep)
+static void cgroup_rstat_flush_locked(struct cgroup *cgrp)
 	__releases(&cgroup_rstat_lock) __acquires(&cgroup_rstat_lock)
 {
 	int cpu;
@@ -161,27 +161,17 @@ static void cgroup_rstat_flush_locked(st
 						       cpu);
 		struct cgroup *pos = NULL;
 
-		raw_spin_lock(cpu_lock);
-		while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu))) {
-			struct cgroup_subsys_state *css;
-
+		raw_spin_lock_irq(cpu_lock);
+		while ((pos = cgroup_rstat_cpu_pop_updated(pos, cgrp, cpu)))
 			cgroup_base_stat_flush(pos, cpu);
 
-			rcu_read_lock();
-			list_for_each_entry_rcu(css, &pos->rstat_css_list,
-						rstat_css_node)
-				css->ss->css_rstat_flush(css, cpu);
-			rcu_read_unlock();
-		}
-		raw_spin_unlock(cpu_lock);
+		raw_spin_unlock_irq(cpu_lock);
 
-		/* if @may_sleep, play nice and yield if necessary */
-		if (may_sleep && (need_resched() ||
-				  spin_needbreak(&cgroup_rstat_lock))) {
-			spin_unlock_irq(&cgroup_rstat_lock);
+		if (need_resched() || spin_needbreak(&cgroup_rstat_lock)) {
+			spin_unlock(&cgroup_rstat_lock);
 			if (!cond_resched())
 				cpu_relax();
-			spin_lock_irq(&cgroup_rstat_lock);
+			spin_lock(&cgroup_rstat_lock);
 		}
 	}
 }
@@ -203,24 +193,9 @@ void cgroup_rstat_flush(struct cgroup *c
 {
 	might_sleep();
 
-	spin_lock_irq(&cgroup_rstat_lock);
-	cgroup_rstat_flush_locked(cgrp, true);
-	spin_unlock_irq(&cgroup_rstat_lock);
-}
-
-/**
- * cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush()
- * @cgrp: target cgroup
- *
- * This function can be called from any context.
- */
-void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp)
-{
-	unsigned long flags;
-
-	spin_lock_irqsave(&cgroup_rstat_lock, flags);
-	cgroup_rstat_flush_locked(cgrp, false);
-	spin_unlock_irqrestore(&cgroup_rstat_lock, flags);
+	spin_lock(&cgroup_rstat_lock);
+	cgroup_rstat_flush_locked(cgrp);
+	spin_unlock(&cgroup_rstat_lock);
 }
 
 /**
@@ -232,21 +207,21 @@ void cgroup_rstat_flush_irqsafe(struct c
  *
  * This function may block.
  */
-void cgroup_rstat_flush_hold(struct cgroup *cgrp)
+static void cgroup_rstat_flush_hold(struct cgroup *cgrp)
 	__acquires(&cgroup_rstat_lock)
 {
 	might_sleep();
-	spin_lock_irq(&cgroup_rstat_lock);
-	cgroup_rstat_flush_locked(cgrp, true);
+	spin_lock(&cgroup_rstat_lock);
+	cgroup_rstat_flush_locked(cgrp);
 }
 
 /**
  * cgroup_rstat_flush_release - release cgroup_rstat_flush_hold()
  */
-void cgroup_rstat_flush_release(void)
+static void cgroup_rstat_flush_release(void)
 	__releases(&cgroup_rstat_lock)
 {
-	spin_unlock_irq(&cgroup_rstat_lock);
+	spin_unlock(&cgroup_rstat_lock);
 }
 
 int cgroup_rstat_init(struct cgroup *cgrp)
Index: linux-5.4.5-rt3/kernel/cpu.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/cpu.c
+++ linux-5.4.5-rt3/kernel/cpu.c
@@ -331,12 +331,12 @@ void lockdep_assert_cpus_held(void)
 
 static void lockdep_acquire_cpus_lock(void)
 {
-	rwsem_acquire(&cpu_hotplug_lock.rw_sem.dep_map, 0, 0, _THIS_IP_);
+	rwsem_acquire(&cpu_hotplug_lock.dep_map, 0, 0, _THIS_IP_);
 }
 
 static void lockdep_release_cpus_lock(void)
 {
-	rwsem_release(&cpu_hotplug_lock.rw_sem.dep_map, 1, _THIS_IP_);
+	rwsem_release(&cpu_hotplug_lock.dep_map, 1, _THIS_IP_);
 }
 
 /*
@@ -849,6 +849,15 @@ static int take_cpu_down(void *_param)
 	int err, cpu = smp_processor_id();
 	int ret;
 
+#ifdef CONFIG_PREEMPT_RT
+	/*
+	 * If any tasks disabled migration before we got here,
+	 * go back and sleep again.
+	 */
+	if (cpu_nr_pinned(cpu))
+		return -EAGAIN;
+#endif
+
 	/* Ensure this CPU doesn't handle any more interrupts. */
 	err = __cpu_disable();
 	if (err < 0)
@@ -878,6 +887,10 @@ static int take_cpu_down(void *_param)
 	return 0;
 }
 
+#ifdef CONFIG_PREEMPT_RT
+struct task_struct *takedown_cpu_task;
+#endif
+
 static int takedown_cpu(unsigned int cpu)
 {
 	struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
@@ -892,11 +905,39 @@ static int takedown_cpu(unsigned int cpu
 	 */
 	irq_lock_sparse();
 
+#ifdef CONFIG_PREEMPT_RT
+	WARN_ON_ONCE(takedown_cpu_task);
+	takedown_cpu_task = current;
+
+again:
+	/*
+	 * If a task pins this CPU after we pass this check, take_cpu_down
+	 * will return -EAGAIN.
+	 */
+	for (;;) {
+		int nr_pinned;
+
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		nr_pinned = cpu_nr_pinned(cpu);
+		if (nr_pinned == 0)
+			break;
+		schedule();
+	}
+	set_current_state(TASK_RUNNING);
+#endif
+
 	/*
 	 * So now all preempt/rcu users must observe !cpu_active().
 	 */
 	err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu));
+#ifdef CONFIG_PREEMPT_RT
+	if (err == -EAGAIN)
+		goto again;
+#endif
 	if (err) {
+#ifdef CONFIG_PREEMPT_RT
+		takedown_cpu_task = NULL;
+#endif
 		/* CPU refused to die */
 		irq_unlock_sparse();
 		/* Unpark the hotplug thread so we can rollback there */
@@ -915,6 +956,9 @@ static int takedown_cpu(unsigned int cpu
 	wait_for_ap_thread(st, false);
 	BUG_ON(st->state != CPUHP_AP_IDLE_DEAD);
 
+#ifdef CONFIG_PREEMPT_RT
+	takedown_cpu_task = NULL;
+#endif
 	/* Interrupts are moved away from the dying cpu, reenable alloc/free */
 	irq_unlock_sparse();
 
Index: linux-5.4.5-rt3/kernel/events/core.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/events/core.c
+++ linux-5.4.5-rt3/kernel/events/core.c
@@ -10256,7 +10256,7 @@ static struct pmu *perf_init_event(struc
 		goto unlock;
 	}
 
-	list_for_each_entry_rcu(pmu, &pmus, entry) {
+	list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
 		ret = perf_try_init_event(pmu, event);
 		if (!ret)
 			goto unlock;
Index: linux-5.4.5-rt3/kernel/exit.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/exit.c
+++ linux-5.4.5-rt3/kernel/exit.c
@@ -161,7 +161,7 @@ static void __exit_signal(struct task_st
 	 * Do this under ->siglock, we can race with another thread
 	 * doing sigqueue_free() if we have SIGQUEUE_PREALLOC signals.
 	 */
-	flush_sigqueue(&tsk->pending);
+	flush_task_sigqueue(tsk);
 	tsk->sighand = NULL;
 	spin_unlock(&sighand->siglock);
 
@@ -258,6 +258,7 @@ void rcuwait_wake_up(struct rcuwait *w)
 		wake_up_process(task);
 	rcu_read_unlock();
 }
+EXPORT_SYMBOL_GPL(rcuwait_wake_up);
 
 /*
  * Determine if a process group is "orphaned", according to the POSIX
Index: linux-5.4.5-rt3/kernel/fork.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/fork.c
+++ linux-5.4.5-rt3/kernel/fork.c
@@ -43,6 +43,7 @@
 #include <linux/hmm.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include <linux/kprobes.h>
 #include <linux/vmacache.h>
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
@@ -289,7 +290,7 @@ static inline void free_thread_stack(str
 			return;
 		}
 
-		vfree_atomic(tsk->stack);
+		vfree(tsk->stack);
 		return;
 	}
 #endif
@@ -696,6 +697,19 @@ void __mmdrop(struct mm_struct *mm)
 }
 EXPORT_SYMBOL_GPL(__mmdrop);
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * RCU callback for delayed mm drop. Not strictly rcu, but we don't
+ * want another facility to make this work.
+ */
+void __mmdrop_delayed(struct rcu_head *rhp)
+{
+	struct mm_struct *mm = container_of(rhp, struct mm_struct, delayed_drop);
+
+	__mmdrop(mm);
+}
+#endif
+
 static void mmdrop_async_fn(struct work_struct *work)
 {
 	struct mm_struct *mm;
@@ -737,6 +751,15 @@ void __put_task_struct(struct task_struc
 	WARN_ON(refcount_read(&tsk->usage));
 	WARN_ON(tsk == current);
 
+	/*
+	 * Remove function-return probe instances associated with this
+	 * task and put them back on the free list.
+	 */
+	kprobe_flush_task(tsk);
+
+	/* Task is done with its stack. */
+	put_task_stack(tsk);
+
 	cgroup_free(tsk);
 	task_numa_free(tsk, true);
 	security_task_free(tsk);
@@ -927,6 +950,7 @@ static struct task_struct *dup_task_stru
 	tsk->splice_pipe = NULL;
 	tsk->task_frag.page = NULL;
 	tsk->wake_q.next = NULL;
+	tsk->wake_q_sleeper.next = NULL;
 
 	account_kernel_stack(tsk, 1);
 
@@ -1900,6 +1924,7 @@ static __latent_entropy struct task_stru
 	spin_lock_init(&p->alloc_lock);
 
 	init_sigpending(&p->pending);
+	p->sigqueue_cache = NULL;
 
 	p->utime = p->stime = p->gtime = 0;
 #ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
Index: linux-5.4.5-rt3/kernel/futex.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/futex.c
+++ linux-5.4.5-rt3/kernel/futex.c
@@ -945,7 +945,9 @@ static void exit_pi_state_list(struct ta
 		if (head->next != next) {
 			/* retain curr->pi_lock for the loop invariant */
 			raw_spin_unlock(&pi_state->pi_mutex.wait_lock);
+			raw_spin_unlock_irq(&curr->pi_lock);
 			spin_unlock(&hb->lock);
+			raw_spin_lock_irq(&curr->pi_lock);
 			put_pi_state(pi_state);
 			continue;
 		}
@@ -1554,6 +1556,7 @@ static int wake_futex_pi(u32 __user *uad
 	struct task_struct *new_owner;
 	bool postunlock = false;
 	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
 	int ret = 0;
 
 	new_owner = rt_mutex_next_owner(&pi_state->pi_mutex);
@@ -1613,13 +1616,13 @@ static int wake_futex_pi(u32 __user *uad
 	pi_state->owner = new_owner;
 	raw_spin_unlock(&new_owner->pi_lock);
 
-	postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q);
-
+	postunlock = __rt_mutex_futex_unlock(&pi_state->pi_mutex, &wake_q,
+					     &wake_sleeper_q);
 out_unlock:
 	raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
 
 	if (postunlock)
-		rt_mutex_postunlock(&wake_q);
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
 
 	return ret;
 }
@@ -2243,6 +2246,16 @@ retry_private:
 				requeue_pi_wake_futex(this, &key2, hb2);
 				drop_count++;
 				continue;
+			} else if (ret == -EAGAIN) {
+				/*
+				 * Waiter was woken by timeout or
+				 * signal and has set pi_blocked_on to
+				 * PI_WAKEUP_INPROGRESS before we
+				 * tried to enqueue it on the rtmutex.
+				 */
+				this->pi_state = NULL;
+				put_pi_state(pi_state);
+				continue;
 			} else if (ret) {
 				/*
 				 * rt_mutex_start_proxy_lock() detected a
@@ -2951,7 +2964,7 @@ retry_private:
 		goto no_block;
 	}
 
-	rt_mutex_init_waiter(&rt_waiter);
+	rt_mutex_init_waiter(&rt_waiter, false);
 
 	/*
 	 * On PREEMPT_RT_FULL, when hb->lock becomes an rt_mutex, we must not
@@ -2967,6 +2980,14 @@ retry_private:
 	 * before __rt_mutex_start_proxy_lock() is done.
 	 */
 	raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
+	/*
+	 * the migrate_disable() here disables migration in the in_atomic() fast
+	 * path which is enabled again in the following spin_unlock(). We have
+	 * one migrate_disable() pending in the slow-path which is reversed
+	 * after the raw_spin_unlock_irq() where we leave the atomic context.
+	 */
+	migrate_disable();
+
 	spin_unlock(q.lock_ptr);
 	/*
 	 * __rt_mutex_start_proxy_lock() unconditionally enqueues the @rt_waiter
@@ -2975,6 +2996,7 @@ retry_private:
 	 */
 	ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
 	raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
+	migrate_enable();
 
 	if (ret) {
 		if (ret == 1)
@@ -3123,10 +3145,19 @@ retry:
 		 * rt_waiter. Also see the WARN in wake_futex_pi().
 		 */
 		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
+		/*
+		 * Magic trickery for now to make the RT migrate disable
+		 * logic happy. The following spin_unlock() happens with
+		 * interrupts disabled so the internal migrate_enable()
+		 * won't undo the migrate_disable() which was issued when
+		 * locking hb->lock.
+		 */
+		migrate_disable();
 		spin_unlock(&hb->lock);
 
 		/* drops pi_state->pi_mutex.wait_lock */
 		ret = wake_futex_pi(uaddr, uval, pi_state);
+		migrate_enable();
 
 		put_pi_state(pi_state);
 
@@ -3298,7 +3329,7 @@ static int futex_wait_requeue_pi(u32 __u
 	struct hrtimer_sleeper timeout, *to;
 	struct futex_pi_state *pi_state = NULL;
 	struct rt_mutex_waiter rt_waiter;
-	struct futex_hash_bucket *hb;
+	struct futex_hash_bucket *hb, *hb2;
 	union futex_key key2 = FUTEX_KEY_INIT;
 	struct futex_q q = futex_q_init;
 	int res, ret;
@@ -3319,7 +3350,7 @@ static int futex_wait_requeue_pi(u32 __u
 	 * The waiter is allocated on our stack, manipulated by the requeue
 	 * code while we sleep on uaddr.
 	 */
-	rt_mutex_init_waiter(&rt_waiter);
+	rt_mutex_init_waiter(&rt_waiter, false);
 
 	ret = get_futex_key(uaddr2, flags & FLAGS_SHARED, &key2, FUTEX_WRITE);
 	if (unlikely(ret != 0))
@@ -3350,20 +3381,55 @@ static int futex_wait_requeue_pi(u32 __u
 	/* Queue the futex_q, drop the hb lock, wait for wakeup. */
 	futex_wait_queue_me(hb, &q, to);
 
-	spin_lock(&hb->lock);
-	ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
-	spin_unlock(&hb->lock);
-	if (ret)
-		goto out_put_keys;
+	/*
+	 * On RT we must avoid races with requeue and trying to block
+	 * on two mutexes (hb->lock and uaddr2's rtmutex) by
+	 * serializing access to pi_blocked_on with pi_lock.
+	 */
+	raw_spin_lock_irq(&current->pi_lock);
+	if (current->pi_blocked_on) {
+		/*
+		 * We have been requeued or are in the process of
+		 * being requeued.
+		 */
+		raw_spin_unlock_irq(&current->pi_lock);
+	} else {
+		/*
+		 * Setting pi_blocked_on to PI_WAKEUP_INPROGRESS
+		 * prevents a concurrent requeue from moving us to the
+		 * uaddr2 rtmutex. After that we can safely acquire
+		 * (and possibly block on) hb->lock.
+		 */
+		current->pi_blocked_on = PI_WAKEUP_INPROGRESS;
+		raw_spin_unlock_irq(&current->pi_lock);
+
+		spin_lock(&hb->lock);
+
+		/*
+		 * Clean up pi_blocked_on. We might leak it otherwise
+		 * when we succeeded with the hb->lock in the fast
+		 * path.
+		 */
+		raw_spin_lock_irq(&current->pi_lock);
+		current->pi_blocked_on = NULL;
+		raw_spin_unlock_irq(&current->pi_lock);
+
+		ret = handle_early_requeue_pi_wakeup(hb, &q, &key2, to);
+		spin_unlock(&hb->lock);
+		if (ret)
+			goto out_put_keys;
+	}
 
 	/*
-	 * In order for us to be here, we know our q.key == key2, and since
-	 * we took the hb->lock above, we also know that futex_requeue() has
-	 * completed and we no longer have to concern ourselves with a wakeup
-	 * race with the atomic proxy lock acquisition by the requeue code. The
-	 * futex_requeue dropped our key1 reference and incremented our key2
-	 * reference count.
+	 * In order to be here, we have either been requeued, are in
+	 * the process of being requeued, or requeue successfully
+	 * acquired uaddr2 on our behalf.  If pi_blocked_on was
+	 * non-null above, we may be racing with a requeue.  Do not
+	 * rely on q->lock_ptr to be hb2->lock until after blocking on
+	 * hb->lock or hb2->lock. The futex_requeue dropped our key1
+	 * reference and incremented our key2 reference count.
 	 */
+	hb2 = hash_futex(&key2);
 
 	/* Check if the requeue code acquired the second futex for us. */
 	if (!q.rt_waiter) {
@@ -3372,7 +3438,8 @@ static int futex_wait_requeue_pi(u32 __u
 		 * did a lock-steal - fix up the PI-state in that case.
 		 */
 		if (q.pi_state && (q.pi_state->owner != current)) {
-			spin_lock(q.lock_ptr);
+			spin_lock(&hb2->lock);
+			BUG_ON(&hb2->lock != q.lock_ptr);
 			ret = fixup_pi_state_owner(uaddr2, &q, current);
 			if (ret && rt_mutex_owner(&q.pi_state->pi_mutex) == current) {
 				pi_state = q.pi_state;
@@ -3383,7 +3450,7 @@ static int futex_wait_requeue_pi(u32 __u
 			 * the requeue_pi() code acquired for us.
 			 */
 			put_pi_state(q.pi_state);
-			spin_unlock(q.lock_ptr);
+			spin_unlock(&hb2->lock);
 		}
 	} else {
 		struct rt_mutex *pi_mutex;
@@ -3397,7 +3464,8 @@ static int futex_wait_requeue_pi(u32 __u
 		pi_mutex = &q.pi_state->pi_mutex;
 		ret = rt_mutex_wait_proxy_lock(pi_mutex, to, &rt_waiter);
 
-		spin_lock(q.lock_ptr);
+		spin_lock(&hb2->lock);
+		BUG_ON(&hb2->lock != q.lock_ptr);
 		if (ret && !rt_mutex_cleanup_proxy_lock(pi_mutex, &rt_waiter))
 			ret = 0;
 
Index: linux-5.4.5-rt3/kernel/irq/handle.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/irq/handle.c
+++ linux-5.4.5-rt3/kernel/irq/handle.c
@@ -185,10 +185,16 @@ irqreturn_t handle_irq_event_percpu(stru
 {
 	irqreturn_t retval;
 	unsigned int flags = 0;
+	struct pt_regs *regs = get_irq_regs();
+	u64 ip = regs ? instruction_pointer(regs) : 0;
 
 	retval = __handle_irq_event_percpu(desc, &flags);
 
-	add_interrupt_randomness(desc->irq_data.irq, flags);
+#ifdef CONFIG_PREEMPT_RT
+	desc->random_ip = ip;
+#else
+	add_interrupt_randomness(desc->irq_data.irq, flags, ip);
+#endif
 
 	if (!noirqdebug)
 		note_interrupt(desc, retval);
Index: linux-5.4.5-rt3/kernel/irq/manage.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/irq/manage.c
+++ linux-5.4.5-rt3/kernel/irq/manage.c
@@ -1099,6 +1099,12 @@ static int irq_thread(void *data)
 		if (action_ret == IRQ_WAKE_THREAD)
 			irq_wake_secondary(desc, action);
 
+#ifdef CONFIG_PREEMPT_RT
+		migrate_disable();
+		add_interrupt_randomness(action->irq, 0,
+				 desc->random_ip ^ (unsigned long) action);
+		migrate_enable();
+#endif
 		wake_threads_waitq(desc);
 	}
 
@@ -2681,7 +2687,7 @@ EXPORT_SYMBOL_GPL(irq_get_irqchip_state)
  *	This call sets the internal irqchip state of an interrupt,
  *	depending on the value of @which.
  *
- *	This function should be called with preemption disabled if the
+ *	This function should be called with migration disabled if the
  *	interrupt controller has per-cpu registers.
  */
 int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
Index: linux-5.4.5-rt3/kernel/irq/spurious.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/irq/spurious.c
+++ linux-5.4.5-rt3/kernel/irq/spurious.c
@@ -442,6 +442,10 @@ MODULE_PARM_DESC(noirqdebug, "Disable ir
 
 static int __init irqfixup_setup(char *str)
 {
+#ifdef CONFIG_PREEMPT_RT
+	pr_warn("irqfixup boot option not supported w/ CONFIG_PREEMPT_RT\n");
+	return 1;
+#endif
 	irqfixup = 1;
 	printk(KERN_WARNING "Misrouted IRQ fixup support enabled.\n");
 	printk(KERN_WARNING "This may impact system performance.\n");
@@ -454,6 +458,10 @@ module_param(irqfixup, int, 0644);
 
 static int __init irqpoll_setup(char *str)
 {
+#ifdef CONFIG_PREEMPT_RT
+	pr_warn("irqpoll boot option not supported w/ CONFIG_PREEMPT_RT\n");
+	return 1;
+#endif
 	irqfixup = 2;
 	printk(KERN_WARNING "Misrouted IRQ fixup and polling support "
 				"enabled\n");
Index: linux-5.4.5-rt3/kernel/irq_work.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/irq_work.c
+++ linux-5.4.5-rt3/kernel/irq_work.c
@@ -18,6 +18,7 @@
 #include <linux/cpu.h>
 #include <linux/notifier.h>
 #include <linux/smp.h>
+#include <linux/interrupt.h>
 #include <asm/processor.h>
 
 
@@ -60,13 +61,19 @@ void __weak arch_irq_work_raise(void)
 /* Enqueue on current CPU, work must already be claimed and preempt disabled */
 static void __irq_work_queue_local(struct irq_work *work)
 {
+	struct llist_head *list;
+	bool lazy_work, realtime = IS_ENABLED(CONFIG_PREEMPT_RT);
+
+	lazy_work = work->flags & IRQ_WORK_LAZY;
+
 	/* If the work is "lazy", handle it from next tick if any */
-	if (work->flags & IRQ_WORK_LAZY) {
-		if (llist_add(&work->llnode, this_cpu_ptr(&lazy_list)) &&
-		    tick_nohz_tick_stopped())
-			arch_irq_work_raise();
-	} else {
-		if (llist_add(&work->llnode, this_cpu_ptr(&raised_list)))
+	if (lazy_work || (realtime && !(work->flags & IRQ_WORK_HARD_IRQ)))
+		list = this_cpu_ptr(&lazy_list);
+	else
+		list = this_cpu_ptr(&raised_list);
+
+	if (llist_add(&work->llnode, list)) {
+		if (!lazy_work || tick_nohz_tick_stopped())
 			arch_irq_work_raise();
 	}
 }
@@ -108,9 +115,16 @@ bool irq_work_queue_on(struct irq_work *
 
 	preempt_disable();
 	if (cpu != smp_processor_id()) {
+		struct llist_head *list;
+
 		/* Arch remote IPI send/receive backend aren't NMI safe */
 		WARN_ON_ONCE(in_nmi());
-		if (llist_add(&work->llnode, &per_cpu(raised_list, cpu)))
+		if (IS_ENABLED(CONFIG_PREEMPT_RT) && !(work->flags & IRQ_WORK_HARD_IRQ))
+			list = &per_cpu(lazy_list, cpu);
+		else
+			list = &per_cpu(raised_list, cpu);
+
+		if (llist_add(&work->llnode, list))
 			arch_send_call_function_single_ipi(cpu);
 	} else {
 		__irq_work_queue_local(work);
@@ -129,9 +143,8 @@ bool irq_work_needs_cpu(void)
 	raised = this_cpu_ptr(&raised_list);
 	lazy = this_cpu_ptr(&lazy_list);
 
-	if (llist_empty(raised) || arch_irq_work_has_interrupt())
-		if (llist_empty(lazy))
-			return false;
+	if (llist_empty(raised) && llist_empty(lazy))
+		return false;
 
 	/* All work should have been flushed before going offline */
 	WARN_ON_ONCE(cpu_is_offline(smp_processor_id()));
@@ -145,8 +158,12 @@ static void irq_work_run_list(struct lli
 	struct llist_node *llnode;
 	unsigned long flags;
 
+#ifndef CONFIG_PREEMPT_RT
+	/*
+	 * nort: On RT IRQ-work may run in SOFTIRQ context.
+	 */
 	BUG_ON(!irqs_disabled());
-
+#endif
 	if (llist_empty(list))
 		return;
 
@@ -178,7 +195,16 @@ static void irq_work_run_list(struct lli
 void irq_work_run(void)
 {
 	irq_work_run_list(this_cpu_ptr(&raised_list));
-	irq_work_run_list(this_cpu_ptr(&lazy_list));
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		/*
+		 * NOTE: we raise softirq via IPI for safety,
+		 * and execute in irq_work_tick() to move the
+		 * overhead from hard to soft irq context.
+		 */
+		if (!llist_empty(this_cpu_ptr(&lazy_list)))
+			raise_softirq(TIMER_SOFTIRQ);
+	} else
+		irq_work_run_list(this_cpu_ptr(&lazy_list));
 }
 EXPORT_SYMBOL_GPL(irq_work_run);
 
@@ -188,8 +214,17 @@ void irq_work_tick(void)
 
 	if (!llist_empty(raised) && !arch_irq_work_has_interrupt())
 		irq_work_run_list(raised);
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_RT))
+		irq_work_run_list(this_cpu_ptr(&lazy_list));
+}
+
+#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT)
+void irq_work_tick_soft(void)
+{
 	irq_work_run_list(this_cpu_ptr(&lazy_list));
 }
+#endif
 
 /*
  * Synchronize against the irq_work @entry, ensures the entry is not
Index: linux-5.4.5-rt3/kernel/kexec_core.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/kexec_core.c
+++ linux-5.4.5-rt3/kernel/kexec_core.c
@@ -972,7 +972,6 @@ void crash_kexec(struct pt_regs *regs)
 	old_cpu = atomic_cmpxchg(&panic_cpu, PANIC_CPU_INVALID, this_cpu);
 	if (old_cpu == PANIC_CPU_INVALID) {
 		/* This is the 1st CPU which comes here, so go ahead. */
-		printk_safe_flush_on_panic();
 		__crash_kexec(regs);
 
 		/*
Index: linux-5.4.5-rt3/kernel/ksysfs.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/ksysfs.c
+++ linux-5.4.5-rt3/kernel/ksysfs.c
@@ -138,6 +138,15 @@ KERNEL_ATTR_RO(vmcoreinfo);
 
 #endif /* CONFIG_CRASH_CORE */
 
+#if defined(CONFIG_PREEMPT_RT)
+static ssize_t realtime_show(struct kobject *kobj,
+			     struct kobj_attribute *attr, char *buf)
+{
+	return sprintf(buf, "%d\n", 1);
+}
+KERNEL_ATTR_RO(realtime);
+#endif
+
 /* whether file capabilities are enabled */
 static ssize_t fscaps_show(struct kobject *kobj,
 				  struct kobj_attribute *attr, char *buf)
@@ -229,6 +238,9 @@ static struct attribute * kernel_attrs[]
 	&rcu_expedited_attr.attr,
 	&rcu_normal_attr.attr,
 #endif
+#ifdef CONFIG_PREEMPT_RT
+	&realtime_attr.attr,
+#endif
 	NULL
 };
 
Index: linux-5.4.5-rt3/kernel/locking/Makefile
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/Makefile
+++ linux-5.4.5-rt3/kernel/locking/Makefile
@@ -3,7 +3,7 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT		:= n
 
-obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
+obj-y += semaphore.o rwsem.o percpu-rwsem.o
 
 ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
@@ -12,19 +12,23 @@ CFLAGS_REMOVE_mutex-debug.o = $(CC_FLAGS
 CFLAGS_REMOVE_rtmutex-debug.o = $(CC_FLAGS_FTRACE)
 endif
 
-obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
 obj-$(CONFIG_LOCKDEP) += lockdep.o
 ifeq ($(CONFIG_PROC_FS),y)
 obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
 endif
 obj-$(CONFIG_SMP) += spinlock.o
-obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
 obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
 obj-$(CONFIG_QUEUED_SPINLOCKS) += qspinlock.o
 obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
+ifneq ($(CONFIG_PREEMPT_RT),y)
+obj-y += mutex.o
+obj-$(CONFIG_LOCK_SPIN_ON_OWNER) += osq_lock.o
+obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
+endif
+obj-$(CONFIG_PREEMPT_RT) += mutex-rt.o rwsem-rt.o rwlock-rt.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
 obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
 obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o
Index: linux-5.4.5-rt3/kernel/locking/lockdep.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/lockdep.c
+++ linux-5.4.5-rt3/kernel/locking/lockdep.c
@@ -4409,6 +4409,7 @@ static void check_flags(unsigned long fl
 		}
 	}
 
+#ifndef CONFIG_PREEMPT_RT
 	/*
 	 * We dont accurately track softirq state in e.g.
 	 * hardirq contexts (such as on 4KSTACKS), so only
@@ -4423,6 +4424,7 @@ static void check_flags(unsigned long fl
 			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
 		}
 	}
+#endif
 
 	if (!debug_locks)
 		print_irqtrace_events(current);
Index: linux-5.4.5-rt3/kernel/locking/locktorture.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/locktorture.c
+++ linux-5.4.5-rt3/kernel/locking/locktorture.c
@@ -16,7 +16,6 @@
 #include <linux/kthread.h>
 #include <linux/sched/rt.h>
 #include <linux/spinlock.h>
-#include <linux/rwlock.h>
 #include <linux/mutex.h>
 #include <linux/rwsem.h>
 #include <linux/smp.h>
Index: linux-5.4.5-rt3/kernel/locking/mutex-rt.c
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/kernel/locking/mutex-rt.c
@@ -0,0 +1,223 @@
+/*
+ * kernel/rt.c
+ *
+ * Real-Time Preemption Support
+ *
+ * started by Ingo Molnar:
+ *
+ *  Copyright (C) 2004-2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
+ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *
+ * historic credit for proving that Linux spinlocks can be implemented via
+ * RT-aware mutexes goes to many people: The Pmutex project (Dirk Grambow
+ * and others) who prototyped it on 2.4 and did lots of comparative
+ * research and analysis; TimeSys, for proving that you can implement a
+ * fully preemptible kernel via the use of IRQ threading and mutexes;
+ * Bill Huey for persuasively arguing on lkml that the mutex model is the
+ * right one; and to MontaVista, who ported pmutexes to 2.6.
+ *
+ * This code is a from-scratch implementation and is not based on pmutexes,
+ * but the idea of converting spinlocks to mutexes is used here too.
+ *
+ * lock debugging, locking tree, deadlock detection:
+ *
+ *  Copyright (C) 2004, LynuxWorks, Inc., Igor Manyilov, Bill Huey
+ *  Released under the General Public License (GPL).
+ *
+ * Includes portions of the generic R/W semaphore implementation from:
+ *
+ *  Copyright (c) 2001   David Howells (dhowells@redhat.com).
+ *  - Derived partially from idea by Andrea Arcangeli <andrea@suse.de>
+ *  - Derived also from comments by Linus
+ *
+ * Pending ownership of locks and ownership stealing:
+ *
+ *  Copyright (C) 2005, Kihon Technologies Inc., Steven Rostedt
+ *
+ *   (also by Steven Rostedt)
+ *    - Converted single pi_lock to individual task locks.
+ *
+ * By Esben Nielsen:
+ *    Doing priority inheritance with help of the scheduler.
+ *
+ *  Copyright (C) 2006, Timesys Corp., Thomas Gleixner <tglx@timesys.com>
+ *  - major rework based on Esben Nielsens initial patch
+ *  - replaced thread_info references by task_struct refs
+ *  - removed task->pending_owner dependency
+ *  - BKL drop/reacquire for semaphore style locks to avoid deadlocks
+ *    in the scheduler return path as discussed with Steven Rostedt
+ *
+ *  Copyright (C) 2006, Kihon Technologies Inc.
+ *    Steven Rostedt <rostedt@goodmis.org>
+ *  - debugged and patched Thomas Gleixner's rework.
+ *  - added back the cmpxchg to the rework.
+ *  - turned atomic require back on for SMP.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/rtmutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/kallsyms.h>
+#include <linux/syscalls.h>
+#include <linux/interrupt.h>
+#include <linux/plist.h>
+#include <linux/fs.h>
+#include <linux/futex.h>
+#include <linux/hrtimer.h>
+
+#include "rtmutex_common.h"
+
+/*
+ * struct mutex functions
+ */
+void __mutex_do_init(struct mutex *mutex, const char *name,
+		     struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)mutex, sizeof(*mutex));
+	lockdep_init_map(&mutex->dep_map, name, key, 0);
+#endif
+	mutex->lock.save_state = 0;
+}
+EXPORT_SYMBOL(__mutex_do_init);
+
+void __lockfunc _mutex_lock(struct mutex *lock)
+{
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	__rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock);
+
+void __lockfunc _mutex_lock_io(struct mutex *lock)
+{
+	int token;
+
+	token = io_schedule_prepare();
+	_mutex_lock(lock);
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_io);
+
+int __lockfunc _mutex_lock_interruptible(struct mutex *lock)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	ret = __rt_mutex_lock_state(&lock->lock, TASK_INTERRUPTIBLE);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_interruptible);
+
+int __lockfunc _mutex_lock_killable(struct mutex *lock)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	ret = __rt_mutex_lock_state(&lock->lock, TASK_KILLABLE);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_killable);
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc _mutex_lock_nested(struct mutex *lock, int subclass)
+{
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+	__rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock_nested);
+
+void __lockfunc _mutex_lock_io_nested(struct mutex *lock, int subclass)
+{
+	int token;
+
+	token = io_schedule_prepare();
+
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+	__rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL_GPL(_mutex_lock_io_nested);
+
+void __lockfunc _mutex_lock_nest_lock(struct mutex *lock, struct lockdep_map *nest)
+{
+	mutex_acquire_nest(&lock->dep_map, 0, 0, nest, _RET_IP_);
+	__rt_mutex_lock_state(&lock->lock, TASK_UNINTERRUPTIBLE);
+}
+EXPORT_SYMBOL(_mutex_lock_nest_lock);
+
+int __lockfunc _mutex_lock_interruptible_nested(struct mutex *lock, int subclass)
+{
+	int ret;
+
+	mutex_acquire_nest(&lock->dep_map, subclass, 0, NULL, _RET_IP_);
+	ret = __rt_mutex_lock_state(&lock->lock, TASK_INTERRUPTIBLE);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_interruptible_nested);
+
+int __lockfunc _mutex_lock_killable_nested(struct mutex *lock, int subclass)
+{
+	int ret;
+
+	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	ret = __rt_mutex_lock_state(&lock->lock, TASK_KILLABLE);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_lock_killable_nested);
+#endif
+
+int __lockfunc _mutex_trylock(struct mutex *lock)
+{
+	int ret = __rt_mutex_trylock(&lock->lock);
+
+	if (ret)
+		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+
+	return ret;
+}
+EXPORT_SYMBOL(_mutex_trylock);
+
+void __lockfunc _mutex_unlock(struct mutex *lock)
+{
+	mutex_release(&lock->dep_map, 1, _RET_IP_);
+	__rt_mutex_unlock(&lock->lock);
+}
+EXPORT_SYMBOL(_mutex_unlock);
+
+/**
+ * atomic_dec_and_mutex_lock - return holding mutex if we dec to 0
+ * @cnt: the atomic which we are to dec
+ * @lock: the mutex to return holding if we dec to 0
+ *
+ * return true and hold lock if we dec to 0, return false otherwise
+ */
+int atomic_dec_and_mutex_lock(atomic_t *cnt, struct mutex *lock)
+{
+	/* dec if we can't possibly hit 0 */
+	if (atomic_add_unless(cnt, -1, 1))
+		return 0;
+	/* we might hit 0, so take the lock */
+	mutex_lock(lock);
+	if (!atomic_dec_and_test(cnt)) {
+		/* when we actually did the dec, we didn't hit 0 */
+		mutex_unlock(lock);
+		return 0;
+	}
+	/* we hit 0, and we hold the lock */
+	return 1;
+}
+EXPORT_SYMBOL(atomic_dec_and_mutex_lock);
Index: linux-5.4.5-rt3/kernel/locking/percpu-rwsem.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/percpu-rwsem.c
+++ linux-5.4.5-rt3/kernel/locking/percpu-rwsem.c
@@ -1,27 +1,29 @@
 // SPDX-License-Identifier: GPL-2.0-only
 #include <linux/atomic.h>
-#include <linux/rwsem.h>
 #include <linux/percpu.h>
+#include <linux/wait.h>
 #include <linux/lockdep.h>
 #include <linux/percpu-rwsem.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
+#include <linux/sched/task.h>
 #include <linux/errno.h>
 
-#include "rwsem.h"
-
 int __percpu_init_rwsem(struct percpu_rw_semaphore *sem,
-			const char *name, struct lock_class_key *rwsem_key)
+			const char *name, struct lock_class_key *key)
 {
 	sem->read_count = alloc_percpu(int);
 	if (unlikely(!sem->read_count))
 		return -ENOMEM;
 
-	/* ->rw_sem represents the whole percpu_rw_semaphore for lockdep */
 	rcu_sync_init(&sem->rss);
-	__init_rwsem(&sem->rw_sem, name, rwsem_key);
 	rcuwait_init(&sem->writer);
-	sem->readers_block = 0;
+	init_waitqueue_head(&sem->waiters);
+	atomic_set(&sem->block, 0);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
 	return 0;
 }
 EXPORT_SYMBOL_GPL(__percpu_init_rwsem);
@@ -41,73 +43,139 @@ void percpu_free_rwsem(struct percpu_rw_
 }
 EXPORT_SYMBOL_GPL(percpu_free_rwsem);
 
-int __percpu_down_read(struct percpu_rw_semaphore *sem, int try)
+static bool __percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
 {
+	__this_cpu_inc(*sem->read_count);
+
 	/*
 	 * Due to having preemption disabled the decrement happens on
 	 * the same CPU as the increment, avoiding the
 	 * increment-on-one-CPU-and-decrement-on-another problem.
 	 *
-	 * If the reader misses the writer's assignment of readers_block, then
-	 * the writer is guaranteed to see the reader's increment.
+	 * If the reader misses the writer's assignment of sem->block, then the
+	 * writer is guaranteed to see the reader's increment.
 	 *
 	 * Conversely, any readers that increment their sem->read_count after
-	 * the writer looks are guaranteed to see the readers_block value,
-	 * which in turn means that they are guaranteed to immediately
-	 * decrement their sem->read_count, so that it doesn't matter that the
-	 * writer missed them.
+	 * the writer looks are guaranteed to see the sem->block value, which
+	 * in turn means that they are guaranteed to immediately decrement
+	 * their sem->read_count, so that it doesn't matter that the writer
+	 * missed them.
 	 */
 
 	smp_mb(); /* A matches D */
 
 	/*
-	 * If !readers_block the critical section starts here, matched by the
+	 * If !sem->block the critical section starts here, matched by the
 	 * release in percpu_up_write().
 	 */
-	if (likely(!smp_load_acquire(&sem->readers_block)))
-		return 1;
+	if (likely(!atomic_read_acquire(&sem->block)))
+		return true;
 
-	/*
-	 * Per the above comment; we still have preemption disabled and
-	 * will thus decrement on the same CPU as we incremented.
-	 */
-	__percpu_up_read(sem);
+	__this_cpu_dec(*sem->read_count);
 
-	if (try)
-		return 0;
+	/* Prod writer to re-evaluate readers_active_check() */
+	rcuwait_wake_up(&sem->writer);
 
-	/*
-	 * We either call schedule() in the wait, or we'll fall through
-	 * and reschedule on the preempt_enable() in percpu_down_read().
-	 */
-	preempt_enable_no_resched();
+	return false;
+}
 
-	/*
-	 * Avoid lockdep for the down/up_read() we already have them.
-	 */
-	__down_read(&sem->rw_sem);
-	this_cpu_inc(*sem->read_count);
-	__up_read(&sem->rw_sem);
+static inline bool __percpu_down_write_trylock(struct percpu_rw_semaphore *sem)
+{
+	if (atomic_read(&sem->block))
+		return false;
 
-	preempt_disable();
-	return 1;
+	return atomic_xchg(&sem->block, 1) == 0;
+}
+
+static bool __percpu_rwsem_trylock(struct percpu_rw_semaphore *sem, bool reader)
+{
+	if (reader) {
+		bool ret;
+
+		preempt_disable();
+		ret = __percpu_down_read_trylock(sem);
+		preempt_enable();
+
+		return ret;
+	}
+	return __percpu_down_write_trylock(sem);
+}
+
+/*
+ * The return value of wait_queue_entry::func means:
+ *
+ *  <0 - error, wakeup is terminated and the error is returned
+ *   0 - no wakeup, a next waiter is tried
+ *  >0 - woken, if EXCLUSIVE, counted towards @nr_exclusive.
+ *
+ * We use EXCLUSIVE for both readers and writers to preserve FIFO order,
+ * and play games with the return value to allow waking multiple readers.
+ *
+ * Specifically, we wake readers until we've woken a single writer, or until a
+ * trylock fails.
+ */
+static int percpu_rwsem_wake_function(struct wait_queue_entry *wq_entry,
+				      unsigned int mode, int wake_flags,
+				      void *key)
+{
+	struct task_struct *p = get_task_struct(wq_entry->private);
+	bool reader = wq_entry->flags & WQ_FLAG_CUSTOM;
+	struct percpu_rw_semaphore *sem = key;
+
+	/* concurrent against percpu_down_write(), can get stolen */
+	if (!__percpu_rwsem_trylock(sem, reader))
+		return 1;
+
+	list_del_init(&wq_entry->entry);
+	smp_store_release(&wq_entry->private, NULL);
+
+	wake_up_process(p);
+	put_task_struct(p);
+
+	return !reader; /* wake (readers until) 1 writer */
 }
-EXPORT_SYMBOL_GPL(__percpu_down_read);
 
-void __percpu_up_read(struct percpu_rw_semaphore *sem)
+static void percpu_rwsem_wait(struct percpu_rw_semaphore *sem, bool reader)
 {
-	smp_mb(); /* B matches C */
+	DEFINE_WAIT_FUNC(wq_entry, percpu_rwsem_wake_function);
+	bool wait;
+
+	spin_lock_irq(&sem->waiters.lock);
 	/*
-	 * In other words, if they see our decrement (presumably to aggregate
-	 * zero, as that is the only time it matters) they will also see our
-	 * critical section.
+	 * Serialize against the wakeup in percpu_up_write(), if we fail
+	 * the trylock, the wakeup must see us on the list.
 	 */
-	__this_cpu_dec(*sem->read_count);
+	wait = !__percpu_rwsem_trylock(sem, reader);
+	if (wait) {
+		wq_entry.flags |= WQ_FLAG_EXCLUSIVE | reader * WQ_FLAG_CUSTOM;
+		__add_wait_queue_entry_tail(&sem->waiters, &wq_entry);
+	}
+	spin_unlock_irq(&sem->waiters.lock);
+
+	while (wait) {
+		set_current_state(TASK_UNINTERRUPTIBLE);
+		if (!smp_load_acquire(&wq_entry.private))
+			break;
+		schedule();
+	}
+	__set_current_state(TASK_RUNNING);
+}
 
-	/* Prod writer to recheck readers_active */
-	rcuwait_wake_up(&sem->writer);
+bool __percpu_down_read(struct percpu_rw_semaphore *sem, bool try)
+{
+	if (__percpu_down_read_trylock(sem))
+		return true;
+
+	if (try)
+		return false;
+
+	preempt_enable();
+	percpu_rwsem_wait(sem, /* .reader = */ true);
+	preempt_disable();
+
+	return true;
 }
-EXPORT_SYMBOL_GPL(__percpu_up_read);
+EXPORT_SYMBOL_GPL(__percpu_down_read);
 
 #define per_cpu_sum(var)						\
 ({									\
@@ -124,6 +192,8 @@ EXPORT_SYMBOL_GPL(__percpu_up_read);
  * zero.  If this sum is zero, then it is stable due to the fact that if any
  * newly arriving readers increment a given counter, they will immediately
  * decrement that same counter.
+ *
+ * Assumes sem->block is set.
  */
 static bool readers_active_check(struct percpu_rw_semaphore *sem)
 {
@@ -142,32 +212,36 @@ static bool readers_active_check(struct
 
 void percpu_down_write(struct percpu_rw_semaphore *sem)
 {
+	might_sleep();
+	rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
+
 	/* Notify readers to take the slow path. */
 	rcu_sync_enter(&sem->rss);
 
-	down_write(&sem->rw_sem);
-
 	/*
-	 * Notify new readers to block; up until now, and thus throughout the
-	 * longish rcu_sync_enter() above, new readers could still come in.
+	 * Try set sem->block; this provides writer-writer exclusion.
+	 * Having sem->block set makes new readers block.
 	 */
-	WRITE_ONCE(sem->readers_block, 1);
+	if (!__percpu_down_write_trylock(sem))
+		percpu_rwsem_wait(sem, /* .reader = */ false);
 
-	smp_mb(); /* D matches A */
+	/* smp_mb() implied by __percpu_down_write_trylock() on success -- D matches A */
 
 	/*
-	 * If they don't see our writer of readers_block, then we are
-	 * guaranteed to see their sem->read_count increment, and therefore
-	 * will wait for them.
+	 * If they don't see our store of sem->block, then we are guaranteed to
+	 * see their sem->read_count increment, and therefore will wait for
+	 * them.
 	 */
 
-	/* Wait for all now active readers to complete. */
+	/* Wait for all active readers to complete. */
 	rcuwait_wait_event(&sem->writer, readers_active_check(sem));
 }
 EXPORT_SYMBOL_GPL(percpu_down_write);
 
 void percpu_up_write(struct percpu_rw_semaphore *sem)
 {
+	rwsem_release(&sem->dep_map, 1, _RET_IP_);
+
 	/*
 	 * Signal the writer is done, no fast path yet.
 	 *
@@ -178,12 +252,12 @@ void percpu_up_write(struct percpu_rw_se
 	 * Therefore we force it through the slow path which guarantees an
 	 * acquire and thereby guarantees the critical section's consistency.
 	 */
-	smp_store_release(&sem->readers_block, 0);
+	atomic_set_release(&sem->block, 0);
 
 	/*
-	 * Release the write lock, this will allow readers back in the game.
+	 * Prod any pending reader/writer to make progress.
 	 */
-	up_write(&sem->rw_sem);
+	__wake_up(&sem->waiters, TASK_NORMAL, 1, sem);
 
 	/*
 	 * Once this completes (at least one RCU-sched grace period hence) the
Index: linux-5.4.5-rt3/kernel/locking/rtmutex.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/rtmutex.c
+++ linux-5.4.5-rt3/kernel/locking/rtmutex.c
@@ -8,6 +8,11 @@
  *  Copyright (C) 2005-2006 Timesys Corp., Thomas Gleixner <tglx@timesys.com>
  *  Copyright (C) 2005 Kihon Technologies Inc., Steven Rostedt
  *  Copyright (C) 2006 Esben Nielsen
+ * Adaptive Spinlocks:
+ *  Copyright (C) 2008 Novell, Inc., Gregory Haskins, Sven Dietrich,
+ *				     and Peter Morreale,
+ * Adaptive Spinlocks simplification:
+ *  Copyright (C) 2008 Red Hat, Inc., Steven Rostedt <srostedt@redhat.com>
  *
  *  See Documentation/locking/rt-mutex-design.rst for details.
  */
@@ -19,6 +24,8 @@
 #include <linux/sched/wake_q.h>
 #include <linux/sched/debug.h>
 #include <linux/timer.h>
+#include <linux/ww_mutex.h>
+#include <linux/blkdev.h>
 
 #include "rtmutex_common.h"
 
@@ -136,6 +143,12 @@ static void fixup_rt_mutex_waiters(struc
 		WRITE_ONCE(*p, owner & ~RT_MUTEX_HAS_WAITERS);
 }
 
+static int rt_mutex_real_waiter(struct rt_mutex_waiter *waiter)
+{
+	return waiter && waiter != PI_WAKEUP_INPROGRESS &&
+		waiter != PI_REQUEUE_INPROGRESS;
+}
+
 /*
  * We can speed up the acquire/release, if there's no debugging state to be
  * set up.
@@ -229,7 +242,7 @@ static inline bool unlock_rt_mutex_safe(
  * Only use with rt_mutex_waiter_{less,equal}()
  */
 #define task_to_waiter(p)	\
-	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
+	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline, .task = (p) }
 
 static inline int
 rt_mutex_waiter_less(struct rt_mutex_waiter *left,
@@ -269,6 +282,27 @@ rt_mutex_waiter_equal(struct rt_mutex_wa
 	return 1;
 }
 
+#define STEAL_NORMAL  0
+#define STEAL_LATERAL 1
+
+static inline int
+rt_mutex_steal(struct rt_mutex *lock, struct rt_mutex_waiter *waiter, int mode)
+{
+	struct rt_mutex_waiter *top_waiter = rt_mutex_top_waiter(lock);
+
+	if (waiter == top_waiter || rt_mutex_waiter_less(waiter, top_waiter))
+		return 1;
+
+	/*
+	 * Note that RT tasks are excluded from lateral-steals
+	 * to prevent the introduction of an unbounded latency.
+	 */
+	if (mode == STEAL_NORMAL || rt_task(waiter->task))
+		return 0;
+
+	return rt_mutex_waiter_equal(waiter, top_waiter);
+}
+
 static void
 rt_mutex_enqueue(struct rt_mutex *lock, struct rt_mutex_waiter *waiter)
 {
@@ -373,6 +407,14 @@ static bool rt_mutex_cond_detect_deadloc
 	return debug_rt_mutex_detect_deadlock(waiter, chwalk);
 }
 
+static void rt_mutex_wake_waiter(struct rt_mutex_waiter *waiter)
+{
+	if (waiter->savestate)
+		wake_up_lock_sleeper(waiter->task);
+	else
+		wake_up_process(waiter->task);
+}
+
 /*
  * Max number of times we'll walk the boosting chain:
  */
@@ -380,7 +422,8 @@ int max_lock_depth = 1024;
 
 static inline struct rt_mutex *task_blocked_on_lock(struct task_struct *p)
 {
-	return p->pi_blocked_on ? p->pi_blocked_on->lock : NULL;
+	return rt_mutex_real_waiter(p->pi_blocked_on) ?
+		p->pi_blocked_on->lock : NULL;
 }
 
 /*
@@ -516,7 +559,7 @@ static int rt_mutex_adjust_prio_chain(st
 	 * reached or the state of the chain has changed while we
 	 * dropped the locks.
 	 */
-	if (!waiter)
+	if (!rt_mutex_real_waiter(waiter))
 		goto out_unlock_pi;
 
 	/*
@@ -696,13 +739,16 @@ static int rt_mutex_adjust_prio_chain(st
 	 * follow here. This is the end of the chain we are walking.
 	 */
 	if (!rt_mutex_owner(lock)) {
+		struct rt_mutex_waiter *lock_top_waiter;
+
 		/*
 		 * If the requeue [7] above changed the top waiter,
 		 * then we need to wake the new top waiter up to try
 		 * to get the lock.
 		 */
-		if (prerequeue_top_waiter != rt_mutex_top_waiter(lock))
-			wake_up_process(rt_mutex_top_waiter(lock)->task);
+		lock_top_waiter = rt_mutex_top_waiter(lock);
+		if (prerequeue_top_waiter != lock_top_waiter)
+			rt_mutex_wake_waiter(lock_top_waiter);
 		raw_spin_unlock_irq(&lock->wait_lock);
 		return 0;
 	}
@@ -803,9 +849,11 @@ static int rt_mutex_adjust_prio_chain(st
  * @task:   The task which wants to acquire the lock
  * @waiter: The waiter that is queued to the lock's wait tree if the
  *	    callsite called task_blocked_on_lock(), otherwise NULL
+ * @mode:   Lock steal mode (STEAL_NORMAL, STEAL_LATERAL)
  */
-static int try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
-				struct rt_mutex_waiter *waiter)
+static int __try_to_take_rt_mutex(struct rt_mutex *lock,
+				  struct task_struct *task,
+				  struct rt_mutex_waiter *waiter, int mode)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -841,12 +889,11 @@ static int try_to_take_rt_mutex(struct r
 	 */
 	if (waiter) {
 		/*
-		 * If waiter is not the highest priority waiter of
-		 * @lock, give up.
+		 * If waiter is not the highest priority waiter of @lock,
+		 * or its peer when lateral steal is allowed, give up.
 		 */
-		if (waiter != rt_mutex_top_waiter(lock))
+		if (!rt_mutex_steal(lock, waiter, mode))
 			return 0;
-
 		/*
 		 * We can acquire the lock. Remove the waiter from the
 		 * lock waiters tree.
@@ -864,14 +911,12 @@ static int try_to_take_rt_mutex(struct r
 		 */
 		if (rt_mutex_has_waiters(lock)) {
 			/*
-			 * If @task->prio is greater than or equal to
-			 * the top waiter priority (kernel view),
-			 * @task lost.
+			 * If @task->prio is greater than the top waiter
+			 * priority (kernel view), or equal to it when a
+			 * lateral steal is forbidden, @task lost.
 			 */
-			if (!rt_mutex_waiter_less(task_to_waiter(task),
-						  rt_mutex_top_waiter(lock)))
+			if (!rt_mutex_steal(lock, task_to_waiter(task), mode))
 				return 0;
-
 			/*
 			 * The current top waiter stays enqueued. We
 			 * don't have to change anything in the lock
@@ -918,6 +963,344 @@ takeit:
 	return 1;
 }
 
+#ifdef CONFIG_PREEMPT_RT
+/*
+ * preemptible spin_lock functions:
+ */
+static inline void rt_spin_lock_fastlock(struct rt_mutex *lock,
+					 void  (*slowfn)(struct rt_mutex *lock))
+{
+	might_sleep_no_state_check();
+
+	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
+		return;
+	else
+		slowfn(lock);
+}
+
+static inline void rt_spin_lock_fastunlock(struct rt_mutex *lock,
+					   void  (*slowfn)(struct rt_mutex *lock))
+{
+	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
+		return;
+	else
+		slowfn(lock);
+}
+#ifdef CONFIG_SMP
+/*
+ * Note that owner is a speculative pointer and dereferencing relies
+ * on rcu_read_lock() and the check against the lock owner.
+ */
+static int adaptive_wait(struct rt_mutex *lock,
+			 struct task_struct *owner)
+{
+	int res = 0;
+
+	rcu_read_lock();
+	for (;;) {
+		if (owner != rt_mutex_owner(lock))
+			break;
+		/*
+		 * Ensure that owner->on_cpu is dereferenced _after_
+		 * checking the above to be valid.
+		 */
+		barrier();
+		if (!owner->on_cpu) {
+			res = 1;
+			break;
+		}
+		cpu_relax();
+	}
+	rcu_read_unlock();
+	return res;
+}
+#else
+static int adaptive_wait(struct rt_mutex *lock,
+			 struct task_struct *orig_owner)
+{
+	return 1;
+}
+#endif
+
+static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
+				   struct rt_mutex_waiter *waiter,
+				   struct task_struct *task,
+				   enum rtmutex_chainwalk chwalk);
+/*
+ * Slow path lock function spin_lock style: this variant is very
+ * careful not to miss any non-lock wakeups.
+ *
+ * We store the current state under p->pi_lock in p->saved_state and
+ * the try_to_wake_up() code handles this accordingly.
+ */
+void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+					  struct rt_mutex_waiter *waiter,
+					  unsigned long flags)
+{
+	struct task_struct *lock_owner, *self = current;
+	struct rt_mutex_waiter *top_waiter;
+	int ret;
+
+	if (__try_to_take_rt_mutex(lock, self, NULL, STEAL_LATERAL))
+		return;
+
+	BUG_ON(rt_mutex_owner(lock) == self);
+
+	/*
+	 * We save whatever state the task is in and we'll restore it
+	 * after acquiring the lock taking real wakeups into account
+	 * as well. We are serialized via pi_lock against wakeups. See
+	 * try_to_wake_up().
+	 */
+	raw_spin_lock(&self->pi_lock);
+	self->saved_state = self->state;
+	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+	raw_spin_unlock(&self->pi_lock);
+
+	ret = task_blocks_on_rt_mutex(lock, waiter, self, RT_MUTEX_MIN_CHAINWALK);
+	BUG_ON(ret);
+
+	for (;;) {
+		/* Try to acquire the lock again. */
+		if (__try_to_take_rt_mutex(lock, self, waiter, STEAL_LATERAL))
+			break;
+
+		top_waiter = rt_mutex_top_waiter(lock);
+		lock_owner = rt_mutex_owner(lock);
+
+		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+		debug_rt_mutex_print_deadlock(waiter);
+
+		if (top_waiter != waiter || adaptive_wait(lock, lock_owner))
+			schedule();
+
+		raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+		raw_spin_lock(&self->pi_lock);
+		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+		raw_spin_unlock(&self->pi_lock);
+	}
+
+	/*
+	 * Restore the task state to current->saved_state. We set it
+	 * to the original state above and the try_to_wake_up() code
+	 * has possibly updated it when a real (non-rtmutex) wakeup
+	 * happened while we were blocked. Clear saved_state so
+	 * try_to_wakeup() does not get confused.
+	 */
+	raw_spin_lock(&self->pi_lock);
+	__set_current_state_no_track(self->saved_state);
+	self->saved_state = TASK_RUNNING;
+	raw_spin_unlock(&self->pi_lock);
+
+	/*
+	 * try_to_take_rt_mutex() sets the waiter bit
+	 * unconditionally. We might have to fix that up:
+	 */
+	fixup_rt_mutex_waiters(lock);
+
+	BUG_ON(rt_mutex_has_waiters(lock) && waiter == rt_mutex_top_waiter(lock));
+	BUG_ON(!RB_EMPTY_NODE(&waiter->tree_entry));
+}
+
+static void noinline __sched rt_spin_lock_slowlock(struct rt_mutex *lock)
+{
+	struct rt_mutex_waiter waiter;
+	unsigned long flags;
+
+	rt_mutex_init_waiter(&waiter, true);
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	rt_spin_lock_slowlock_locked(lock, &waiter, flags);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	debug_rt_mutex_free_waiter(&waiter);
+}
+
+static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
+					     struct wake_q_head *wake_q,
+					     struct wake_q_head *wq_sleeper);
+/*
+ * Slow path to release a rt_mutex spin_lock style
+ */
+void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock)
+{
+	unsigned long flags;
+	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
+	bool postunlock;
+
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	postunlock = __rt_mutex_unlock_common(lock, &wake_q, &wake_sleeper_q);
+	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+
+	if (postunlock)
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
+}
+
+void __lockfunc rt_spin_lock(spinlock_t *lock)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	spin_acquire(&lock->dep_map, 0, 0, _RET_IP_);
+	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+}
+EXPORT_SYMBOL(rt_spin_lock);
+
+void __lockfunc __rt_spin_lock(struct rt_mutex *lock)
+{
+	rt_spin_lock_fastlock(lock, rt_spin_lock_slowlock);
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+void __lockfunc rt_spin_lock_nested(spinlock_t *lock, int subclass)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
+	rt_spin_lock_fastlock(&lock->lock, rt_spin_lock_slowlock);
+}
+EXPORT_SYMBOL(rt_spin_lock_nested);
+#endif
+
+void __lockfunc rt_spin_unlock(spinlock_t *lock)
+{
+	/* NOTE: we always pass in '1' for nested, for simplicity */
+	spin_release(&lock->dep_map, 1, _RET_IP_);
+	rt_spin_lock_fastunlock(&lock->lock, rt_spin_lock_slowunlock);
+	migrate_enable();
+	rcu_read_unlock();
+	sleeping_lock_dec();
+}
+EXPORT_SYMBOL(rt_spin_unlock);
+
+void __lockfunc __rt_spin_unlock(struct rt_mutex *lock)
+{
+	rt_spin_lock_fastunlock(lock, rt_spin_lock_slowunlock);
+}
+EXPORT_SYMBOL(__rt_spin_unlock);
+
+/*
+ * Wait for the lock to get unlocked: instead of polling for an unlock
+ * (like raw spinlocks do), we lock and unlock, to force the kernel to
+ * schedule if there's contention:
+ */
+void __lockfunc rt_spin_unlock_wait(spinlock_t *lock)
+{
+	spin_lock(lock);
+	spin_unlock(lock);
+}
+EXPORT_SYMBOL(rt_spin_unlock_wait);
+
+int __lockfunc rt_spin_trylock(spinlock_t *lock)
+{
+	int ret;
+
+	sleeping_lock_inc();
+	migrate_disable();
+	ret = __rt_mutex_trylock(&lock->lock);
+	if (ret) {
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+	} else {
+		migrate_enable();
+		sleeping_lock_dec();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock);
+
+int __lockfunc rt_spin_trylock_bh(spinlock_t *lock)
+{
+	int ret;
+
+	local_bh_disable();
+	ret = __rt_mutex_trylock(&lock->lock);
+	if (ret) {
+		sleeping_lock_inc();
+		rcu_read_lock();
+		migrate_disable();
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+	} else
+		local_bh_enable();
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_bh);
+
+int __lockfunc rt_spin_trylock_irqsave(spinlock_t *lock, unsigned long *flags)
+{
+	int ret;
+
+	*flags = 0;
+	ret = __rt_mutex_trylock(&lock->lock);
+	if (ret) {
+		sleeping_lock_inc();
+		rcu_read_lock();
+		migrate_disable();
+		spin_acquire(&lock->dep_map, 0, 1, _RET_IP_);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_spin_trylock_irqsave);
+
+void
+__rt_spin_lock_init(spinlock_t *lock, const char *name, struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held lock:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+}
+EXPORT_SYMBOL(__rt_spin_lock_init);
+
+#endif /* PREEMPT_RT */
+
+#ifdef CONFIG_PREEMPT_RT
+	static inline int __sched
+__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
+	struct ww_acquire_ctx *hold_ctx = READ_ONCE(ww->ctx);
+
+	if (!hold_ctx)
+		return 0;
+
+	if (unlikely(ctx == hold_ctx))
+		return -EALREADY;
+
+	if (ctx->stamp - hold_ctx->stamp <= LONG_MAX &&
+	    (ctx->stamp != hold_ctx->stamp || ctx > hold_ctx)) {
+#ifdef CONFIG_DEBUG_MUTEXES
+		DEBUG_LOCKS_WARN_ON(ctx->contending_lock);
+		ctx->contending_lock = ww;
+#endif
+		return -EDEADLK;
+	}
+
+	return 0;
+}
+#else
+	static inline int __sched
+__mutex_lock_check_stamp(struct rt_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	BUG();
+	return 0;
+}
+
+#endif
+
+static inline int
+try_to_take_rt_mutex(struct rt_mutex *lock, struct task_struct *task,
+		     struct rt_mutex_waiter *waiter)
+{
+	return __try_to_take_rt_mutex(lock, task, waiter, STEAL_NORMAL);
+}
+
 /*
  * Task blocks on lock.
  *
@@ -950,6 +1333,22 @@ static int task_blocks_on_rt_mutex(struc
 		return -EDEADLK;
 
 	raw_spin_lock(&task->pi_lock);
+	/*
+	 * In the case of futex requeue PI, this will be a proxy
+	 * lock. The task will wake unaware that it is enqueueed on
+	 * this lock. Avoid blocking on two locks and corrupting
+	 * pi_blocked_on via the PI_WAKEUP_INPROGRESS
+	 * flag. futex_wait_requeue_pi() sets this when it wakes up
+	 * before requeue (due to a signal or timeout). Do not enqueue
+	 * the task if PI_WAKEUP_INPROGRESS is set.
+	 */
+	if (task != current && task->pi_blocked_on == PI_WAKEUP_INPROGRESS) {
+		raw_spin_unlock(&task->pi_lock);
+		return -EAGAIN;
+	}
+
+       BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on));
+
 	waiter->task = task;
 	waiter->lock = lock;
 	waiter->prio = task->prio;
@@ -973,7 +1372,7 @@ static int task_blocks_on_rt_mutex(struc
 		rt_mutex_enqueue_pi(owner, waiter);
 
 		rt_mutex_adjust_prio(owner);
-		if (owner->pi_blocked_on)
+		if (rt_mutex_real_waiter(owner->pi_blocked_on))
 			chain_walk = 1;
 	} else if (rt_mutex_cond_detect_deadlock(waiter, chwalk)) {
 		chain_walk = 1;
@@ -1015,6 +1414,7 @@ static int task_blocks_on_rt_mutex(struc
  * Called with lock->wait_lock held and interrupts disabled.
  */
 static void mark_wakeup_next_waiter(struct wake_q_head *wake_q,
+				    struct wake_q_head *wake_sleeper_q,
 				    struct rt_mutex *lock)
 {
 	struct rt_mutex_waiter *waiter;
@@ -1054,7 +1454,10 @@ static void mark_wakeup_next_waiter(stru
 	 * Pairs with preempt_enable() in rt_mutex_postunlock();
 	 */
 	preempt_disable();
-	wake_q_add(wake_q, waiter->task);
+	if (waiter->savestate)
+		wake_q_add_sleeper(wake_sleeper_q, waiter->task);
+	else
+		wake_q_add(wake_q, waiter->task);
 	raw_spin_unlock(&current->pi_lock);
 }
 
@@ -1069,7 +1472,7 @@ static void remove_waiter(struct rt_mute
 {
 	bool is_top_waiter = (waiter == rt_mutex_top_waiter(lock));
 	struct task_struct *owner = rt_mutex_owner(lock);
-	struct rt_mutex *next_lock;
+	struct rt_mutex *next_lock = NULL;
 
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1095,7 +1498,8 @@ static void remove_waiter(struct rt_mute
 	rt_mutex_adjust_prio(owner);
 
 	/* Store the lock on which owner is blocked or NULL */
-	next_lock = task_blocked_on_lock(owner);
+	if (rt_mutex_real_waiter(owner->pi_blocked_on))
+		next_lock = task_blocked_on_lock(owner);
 
 	raw_spin_unlock(&owner->pi_lock);
 
@@ -1131,26 +1535,28 @@ void rt_mutex_adjust_pi(struct task_stru
 	raw_spin_lock_irqsave(&task->pi_lock, flags);
 
 	waiter = task->pi_blocked_on;
-	if (!waiter || rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
+	if (!rt_mutex_real_waiter(waiter) ||
+	    rt_mutex_waiter_equal(waiter, task_to_waiter(task))) {
 		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 		return;
 	}
 	next_lock = waiter->lock;
-	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 
 	/* gets dropped in rt_mutex_adjust_prio_chain()! */
 	get_task_struct(task);
 
+	raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 	rt_mutex_adjust_prio_chain(task, RT_MUTEX_MIN_CHAINWALK, NULL,
 				   next_lock, NULL, task);
 }
 
-void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter)
+void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savestate)
 {
 	debug_rt_mutex_init_waiter(waiter);
 	RB_CLEAR_NODE(&waiter->pi_tree_entry);
 	RB_CLEAR_NODE(&waiter->tree_entry);
 	waiter->task = NULL;
+	waiter->savestate = savestate;
 }
 
 /**
@@ -1166,7 +1572,8 @@ void rt_mutex_init_waiter(struct rt_mute
 static int __sched
 __rt_mutex_slowlock(struct rt_mutex *lock, int state,
 		    struct hrtimer_sleeper *timeout,
-		    struct rt_mutex_waiter *waiter)
+		    struct rt_mutex_waiter *waiter,
+		    struct ww_acquire_ctx *ww_ctx)
 {
 	int ret = 0;
 
@@ -1175,16 +1582,17 @@ __rt_mutex_slowlock(struct rt_mutex *loc
 		if (try_to_take_rt_mutex(lock, current, waiter))
 			break;
 
-		/*
-		 * TASK_INTERRUPTIBLE checks for signals and
-		 * timeout. Ignored otherwise.
-		 */
-		if (likely(state == TASK_INTERRUPTIBLE)) {
-			/* Signal pending? */
-			if (signal_pending(current))
-				ret = -EINTR;
-			if (timeout && !timeout->task)
-				ret = -ETIMEDOUT;
+		if (timeout && !timeout->task) {
+			ret = -ETIMEDOUT;
+			break;
+		}
+		if (signal_pending_state(state, current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (ww_ctx && ww_ctx->acquired > 0) {
+			ret = __mutex_lock_check_stamp(lock, ww_ctx);
 			if (ret)
 				break;
 		}
@@ -1223,33 +1631,104 @@ static void rt_mutex_handle_deadlock(int
 	}
 }
 
-/*
- * Slow path lock function:
- */
-static int __sched
-rt_mutex_slowlock(struct rt_mutex *lock, int state,
-		  struct hrtimer_sleeper *timeout,
-		  enum rtmutex_chainwalk chwalk)
+static __always_inline void ww_mutex_lock_acquired(struct ww_mutex *ww,
+						   struct ww_acquire_ctx *ww_ctx)
 {
-	struct rt_mutex_waiter waiter;
-	unsigned long flags;
-	int ret = 0;
+#ifdef CONFIG_DEBUG_MUTEXES
+	/*
+	 * If this WARN_ON triggers, you used ww_mutex_lock to acquire,
+	 * but released with a normal mutex_unlock in this call.
+	 *
+	 * This should never happen, always use ww_mutex_unlock.
+	 */
+	DEBUG_LOCKS_WARN_ON(ww->ctx);
 
-	rt_mutex_init_waiter(&waiter);
+	/*
+	 * Not quite done after calling ww_acquire_done() ?
+	 */
+	DEBUG_LOCKS_WARN_ON(ww_ctx->done_acquire);
+
+	if (ww_ctx->contending_lock) {
+		/*
+		 * After -EDEADLK you tried to
+		 * acquire a different ww_mutex? Bad!
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->contending_lock != ww);
+
+		/*
+		 * You called ww_mutex_lock after receiving -EDEADLK,
+		 * but 'forgot' to unlock everything else first?
+		 */
+		DEBUG_LOCKS_WARN_ON(ww_ctx->acquired > 0);
+		ww_ctx->contending_lock = NULL;
+	}
 
 	/*
-	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
-	 * be called in early boot if the cmpxchg() fast path is disabled
-	 * (debug, no architecture support). In this case we will acquire the
-	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
-	 * enable interrupts in that early boot case. So we need to use the
-	 * irqsave/restore variants.
+	 * Naughty, using a different class will lead to undefined behavior!
 	 */
-	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class);
+#endif
+	ww_ctx->acquired++;
+}
+
+#ifdef CONFIG_PREEMPT_RT
+static void ww_mutex_account_lock(struct rt_mutex *lock,
+				  struct ww_acquire_ctx *ww_ctx)
+{
+	struct ww_mutex *ww = container_of(lock, struct ww_mutex, base.lock);
+	struct rt_mutex_waiter *waiter, *n;
+
+	/*
+	 * This branch gets optimized out for the common case,
+	 * and is only important for ww_mutex_lock.
+	 */
+	ww_mutex_lock_acquired(ww, ww_ctx);
+	ww->ctx = ww_ctx;
+
+	/*
+	 * Give any possible sleeping processes the chance to wake up,
+	 * so they can recheck if they have to back off.
+	 */
+	rbtree_postorder_for_each_entry_safe(waiter, n, &lock->waiters.rb_root,
+					     tree_entry) {
+		/* XXX debug rt mutex waiter wakeup */
+
+		BUG_ON(waiter->lock != lock);
+		rt_mutex_wake_waiter(waiter);
+	}
+}
+
+#else
+
+static void ww_mutex_account_lock(struct rt_mutex *lock,
+				  struct ww_acquire_ctx *ww_ctx)
+{
+	BUG();
+}
+#endif
+
+int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+				     struct hrtimer_sleeper *timeout,
+				     enum rtmutex_chainwalk chwalk,
+				     struct ww_acquire_ctx *ww_ctx,
+				     struct rt_mutex_waiter *waiter)
+{
+	int ret;
+
+#ifdef CONFIG_PREEMPT_RT
+	if (ww_ctx) {
+		struct ww_mutex *ww;
+
+		ww = container_of(lock, struct ww_mutex, base.lock);
+		if (unlikely(ww_ctx == READ_ONCE(ww->ctx)))
+			return -EALREADY;
+	}
+#endif
 
 	/* Try to acquire the lock again: */
 	if (try_to_take_rt_mutex(lock, current, NULL)) {
-		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+		if (ww_ctx)
+			ww_mutex_account_lock(lock, ww_ctx);
 		return 0;
 	}
 
@@ -1259,16 +1738,26 @@ rt_mutex_slowlock(struct rt_mutex *lock,
 	if (unlikely(timeout))
 		hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
 
-	ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk);
+	ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk);
 
-	if (likely(!ret))
+	if (likely(!ret)) {
 		/* sleep on the mutex */
-		ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
+		ret = __rt_mutex_slowlock(lock, state, timeout, waiter,
+					  ww_ctx);
+	} else if (ww_ctx) {
+		/* ww_mutex received EDEADLK, let it become EALREADY */
+		ret = __mutex_lock_check_stamp(lock, ww_ctx);
+		BUG_ON(!ret);
+	}
 
 	if (unlikely(ret)) {
 		__set_current_state(TASK_RUNNING);
-		remove_waiter(lock, &waiter);
-		rt_mutex_handle_deadlock(ret, chwalk, &waiter);
+		remove_waiter(lock, waiter);
+		/* ww_mutex wants to report EDEADLK/EALREADY, let it */
+		if (!ww_ctx)
+			rt_mutex_handle_deadlock(ret, chwalk, waiter);
+	} else if (ww_ctx) {
+		ww_mutex_account_lock(lock, ww_ctx);
 	}
 
 	/*
@@ -1276,6 +1765,36 @@ rt_mutex_slowlock(struct rt_mutex *lock,
 	 * unconditionally. We might have to fix that up.
 	 */
 	fixup_rt_mutex_waiters(lock);
+	return ret;
+}
+
+/*
+ * Slow path lock function:
+ */
+static int __sched
+rt_mutex_slowlock(struct rt_mutex *lock, int state,
+		  struct hrtimer_sleeper *timeout,
+		  enum rtmutex_chainwalk chwalk,
+		  struct ww_acquire_ctx *ww_ctx)
+{
+	struct rt_mutex_waiter waiter;
+	unsigned long flags;
+	int ret = 0;
+
+	rt_mutex_init_waiter(&waiter, false);
+
+	/*
+	 * Technically we could use raw_spin_[un]lock_irq() here, but this can
+	 * be called in early boot if the cmpxchg() fast path is disabled
+	 * (debug, no architecture support). In this case we will acquire the
+	 * rtmutex with lock->wait_lock held. But we cannot unconditionally
+	 * enable interrupts in that early boot case. So we need to use the
+	 * irqsave/restore variants.
+	 */
+	raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+	ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, ww_ctx,
+				       &waiter);
 
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
@@ -1336,7 +1855,8 @@ static inline int rt_mutex_slowtrylock(s
  * Return whether the current task needs to call rt_mutex_postunlock().
  */
 static bool __sched rt_mutex_slowunlock(struct rt_mutex *lock,
-					struct wake_q_head *wake_q)
+					struct wake_q_head *wake_q,
+					struct wake_q_head *wake_sleeper_q)
 {
 	unsigned long flags;
 
@@ -1390,7 +1910,7 @@ static bool __sched rt_mutex_slowunlock(
 	 *
 	 * Queue the next waiter for wakeup once we release the wait_lock.
 	 */
-	mark_wakeup_next_waiter(wake_q, lock);
+	mark_wakeup_next_waiter(wake_q, wake_sleeper_q, lock);
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	return true; /* call rt_mutex_postunlock() */
@@ -1404,29 +1924,45 @@ static bool __sched rt_mutex_slowunlock(
  */
 static inline int
 rt_mutex_fastlock(struct rt_mutex *lock, int state,
+		  struct ww_acquire_ctx *ww_ctx,
 		  int (*slowfn)(struct rt_mutex *lock, int state,
 				struct hrtimer_sleeper *timeout,
-				enum rtmutex_chainwalk chwalk))
+				enum rtmutex_chainwalk chwalk,
+				struct ww_acquire_ctx *ww_ctx))
 {
 	if (likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
 		return 0;
 
-	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK);
+	/*
+	 * If rt_mutex blocks, the function sched_submit_work will not call
+	 * blk_schedule_flush_plug (because tsk_is_pi_blocked would be true).
+	 * We must call blk_schedule_flush_plug here, if we don't call it,
+	 * a deadlock in I/O may happen.
+	 */
+	if (unlikely(blk_needs_flush_plug(current)))
+		blk_schedule_flush_plug(current);
+
+	return slowfn(lock, state, NULL, RT_MUTEX_MIN_CHAINWALK, ww_ctx);
 }
 
 static inline int
 rt_mutex_timed_fastlock(struct rt_mutex *lock, int state,
 			struct hrtimer_sleeper *timeout,
 			enum rtmutex_chainwalk chwalk,
+			struct ww_acquire_ctx *ww_ctx,
 			int (*slowfn)(struct rt_mutex *lock, int state,
 				      struct hrtimer_sleeper *timeout,
-				      enum rtmutex_chainwalk chwalk))
+				      enum rtmutex_chainwalk chwalk,
+				      struct ww_acquire_ctx *ww_ctx))
 {
 	if (chwalk == RT_MUTEX_MIN_CHAINWALK &&
 	    likely(rt_mutex_cmpxchg_acquire(lock, NULL, current)))
 		return 0;
 
-	return slowfn(lock, state, timeout, chwalk);
+	if (unlikely(blk_needs_flush_plug(current)))
+		blk_schedule_flush_plug(current);
+
+	return slowfn(lock, state, timeout, chwalk, ww_ctx);
 }
 
 static inline int
@@ -1442,9 +1978,11 @@ rt_mutex_fasttrylock(struct rt_mutex *lo
 /*
  * Performs the wakeup of the the top-waiter and re-enables preemption.
  */
-void rt_mutex_postunlock(struct wake_q_head *wake_q)
+void rt_mutex_postunlock(struct wake_q_head *wake_q,
+			 struct wake_q_head *wake_sleeper_q)
 {
 	wake_up_q(wake_q);
+	wake_up_q_sleeper(wake_sleeper_q);
 
 	/* Pairs with preempt_disable() in rt_mutex_slowunlock() */
 	preempt_enable();
@@ -1453,23 +1991,46 @@ void rt_mutex_postunlock(struct wake_q_h
 static inline void
 rt_mutex_fastunlock(struct rt_mutex *lock,
 		    bool (*slowfn)(struct rt_mutex *lock,
-				   struct wake_q_head *wqh))
+				   struct wake_q_head *wqh,
+				   struct wake_q_head *wq_sleeper))
 {
 	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
 
 	if (likely(rt_mutex_cmpxchg_release(lock, current, NULL)))
 		return;
 
-	if (slowfn(lock, &wake_q))
-		rt_mutex_postunlock(&wake_q);
+	if (slowfn(lock, &wake_q, &wake_sleeper_q))
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
 }
 
-static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
+int __sched __rt_mutex_lock_state(struct rt_mutex *lock, int state)
 {
 	might_sleep();
+	return rt_mutex_fastlock(lock, state, NULL, rt_mutex_slowlock);
+}
+
+/**
+ * rt_mutex_lock_state - lock a rt_mutex with a given state
+ *
+ * @lock:      The rt_mutex to be locked
+ * @state:     The state to set when blocking on the rt_mutex
+ */
+static inline int __sched rt_mutex_lock_state(struct rt_mutex *lock,
+					      unsigned int subclass, int state)
+{
+	int ret;
 
 	mutex_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
-	rt_mutex_fastlock(lock, TASK_UNINTERRUPTIBLE, rt_mutex_slowlock);
+	ret = __rt_mutex_lock_state(lock, state);
+	if (ret)
+		mutex_release(&lock->dep_map, 1, _RET_IP_);
+	return ret;
+}
+
+static inline void __rt_mutex_lock(struct rt_mutex *lock, unsigned int subclass)
+{
+	rt_mutex_lock_state(lock, subclass, TASK_UNINTERRUPTIBLE);
 }
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
@@ -1510,16 +2071,7 @@ EXPORT_SYMBOL_GPL(rt_mutex_lock);
  */
 int __sched rt_mutex_lock_interruptible(struct rt_mutex *lock)
 {
-	int ret;
-
-	might_sleep();
-
-	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
-	ret = rt_mutex_fastlock(lock, TASK_INTERRUPTIBLE, rt_mutex_slowlock);
-	if (ret)
-		mutex_release(&lock->dep_map, 1, _RET_IP_);
-
-	return ret;
+	return rt_mutex_lock_state(lock, 0, TASK_INTERRUPTIBLE);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_lock_interruptible);
 
@@ -1537,6 +2089,22 @@ int __sched __rt_mutex_futex_trylock(str
 }
 
 /**
+ * rt_mutex_lock_killable - lock a rt_mutex killable
+ *
+ * @lock:              the rt_mutex to be locked
+ * @detect_deadlock:   deadlock detection on/off
+ *
+ * Returns:
+ *  0          on success
+ * -EINTR      when interrupted by a signal
+ */
+int __sched rt_mutex_lock_killable(struct rt_mutex *lock)
+{
+	return rt_mutex_lock_state(lock, 0, TASK_KILLABLE);
+}
+EXPORT_SYMBOL_GPL(rt_mutex_lock_killable);
+
+/**
  * rt_mutex_timed_lock - lock a rt_mutex interruptible
  *			the timeout structure is provided
  *			by the caller
@@ -1559,6 +2127,7 @@ rt_mutex_timed_lock(struct rt_mutex *loc
 	mutex_acquire(&lock->dep_map, 0, 0, _RET_IP_);
 	ret = rt_mutex_timed_fastlock(lock, TASK_INTERRUPTIBLE, timeout,
 				       RT_MUTEX_MIN_CHAINWALK,
+				       NULL,
 				       rt_mutex_slowlock);
 	if (ret)
 		mutex_release(&lock->dep_map, 1, _RET_IP_);
@@ -1567,6 +2136,18 @@ rt_mutex_timed_lock(struct rt_mutex *loc
 }
 EXPORT_SYMBOL_GPL(rt_mutex_timed_lock);
 
+int __sched __rt_mutex_trylock(struct rt_mutex *lock)
+{
+#ifdef CONFIG_PREEMPT_RT
+	if (WARN_ON_ONCE(in_irq() || in_nmi()))
+#else
+	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
+#endif
+		return 0;
+
+	return rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+}
+
 /**
  * rt_mutex_trylock - try to lock a rt_mutex
  *
@@ -1582,10 +2163,7 @@ int __sched rt_mutex_trylock(struct rt_m
 {
 	int ret;
 
-	if (WARN_ON_ONCE(in_irq() || in_nmi() || in_serving_softirq()))
-		return 0;
-
-	ret = rt_mutex_fasttrylock(lock, rt_mutex_slowtrylock);
+	ret = __rt_mutex_trylock(lock);
 	if (ret)
 		mutex_acquire(&lock->dep_map, 0, 1, _RET_IP_);
 
@@ -1593,6 +2171,11 @@ int __sched rt_mutex_trylock(struct rt_m
 }
 EXPORT_SYMBOL_GPL(rt_mutex_trylock);
 
+void __sched __rt_mutex_unlock(struct rt_mutex *lock)
+{
+	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+}
+
 /**
  * rt_mutex_unlock - unlock a rt_mutex
  *
@@ -1601,16 +2184,13 @@ EXPORT_SYMBOL_GPL(rt_mutex_trylock);
 void __sched rt_mutex_unlock(struct rt_mutex *lock)
 {
 	mutex_release(&lock->dep_map, 1, _RET_IP_);
-	rt_mutex_fastunlock(lock, rt_mutex_slowunlock);
+	__rt_mutex_unlock(lock);
 }
 EXPORT_SYMBOL_GPL(rt_mutex_unlock);
 
-/**
- * Futex variant, that since futex variants do not use the fast-path, can be
- * simple and will not need to retry.
- */
-bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				    struct wake_q_head *wake_q)
+static bool __sched __rt_mutex_unlock_common(struct rt_mutex *lock,
+					     struct wake_q_head *wake_q,
+					     struct wake_q_head *wq_sleeper)
 {
 	lockdep_assert_held(&lock->wait_lock);
 
@@ -1627,23 +2207,35 @@ bool __sched __rt_mutex_futex_unlock(str
 	 * avoid inversion prior to the wakeup.  preempt_disable()
 	 * therein pairs with rt_mutex_postunlock().
 	 */
-	mark_wakeup_next_waiter(wake_q, lock);
+	mark_wakeup_next_waiter(wake_q, wq_sleeper, lock);
 
 	return true; /* call postunlock() */
 }
 
+/**
+ * Futex variant, that since futex variants do not use the fast-path, can be
+ * simple and will not need to retry.
+ */
+bool __sched __rt_mutex_futex_unlock(struct rt_mutex *lock,
+				     struct wake_q_head *wake_q,
+				     struct wake_q_head *wq_sleeper)
+{
+	return __rt_mutex_unlock_common(lock, wake_q, wq_sleeper);
+}
+
 void __sched rt_mutex_futex_unlock(struct rt_mutex *lock)
 {
 	DEFINE_WAKE_Q(wake_q);
+	DEFINE_WAKE_Q(wake_sleeper_q);
 	unsigned long flags;
 	bool postunlock;
 
 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
-	postunlock = __rt_mutex_futex_unlock(lock, &wake_q);
+	postunlock = __rt_mutex_futex_unlock(lock, &wake_q, &wake_sleeper_q);
 	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
 
 	if (postunlock)
-		rt_mutex_postunlock(&wake_q);
+		rt_mutex_postunlock(&wake_q, &wake_sleeper_q);
 }
 
 /**
@@ -1682,7 +2274,7 @@ void __rt_mutex_init(struct rt_mutex *lo
 	if (name && key)
 		debug_rt_mutex_init(lock, name, key);
 }
-EXPORT_SYMBOL_GPL(__rt_mutex_init);
+EXPORT_SYMBOL(__rt_mutex_init);
 
 /**
  * rt_mutex_init_proxy_locked - initialize and lock a rt_mutex on behalf of a
@@ -1702,6 +2294,14 @@ void rt_mutex_init_proxy_locked(struct r
 				struct task_struct *proxy_owner)
 {
 	__rt_mutex_init(lock, NULL, NULL);
+#ifdef CONFIG_DEBUG_SPINLOCK
+	/*
+	 * get another key class for the wait_lock. LOCK_PI and UNLOCK_PI is
+	 * holding the ->wait_lock of the proxy_lock while unlocking a sleeping
+	 * lock.
+	 */
+	raw_spin_lock_init(&lock->wait_lock);
+#endif
 	debug_rt_mutex_proxy_lock(lock, proxy_owner);
 	rt_mutex_set_owner(lock, proxy_owner);
 }
@@ -1725,6 +2325,26 @@ void rt_mutex_proxy_unlock(struct rt_mut
 	rt_mutex_set_owner(lock, NULL);
 }
 
+static void fixup_rt_mutex_blocked(struct rt_mutex *lock)
+{
+	struct task_struct *tsk = current;
+	/*
+	 * RT has a problem here when the wait got interrupted by a timeout
+	 * or a signal. task->pi_blocked_on is still set. The task must
+	 * acquire the hash bucket lock when returning from this function.
+	 *
+	 * If the hash bucket lock is contended then the
+	 * BUG_ON(rt_mutex_real_waiter(task->pi_blocked_on)) in
+	 * task_blocks_on_rt_mutex() will trigger. This can be avoided by
+	 * clearing task->pi_blocked_on which removes the task from the
+	 * boosting chain of the rtmutex. That's correct because the task
+	 * is not longer blocked on it.
+	 */
+	raw_spin_lock(&tsk->pi_lock);
+	tsk->pi_blocked_on = NULL;
+	raw_spin_unlock(&tsk->pi_lock);
+}
+
 /**
  * __rt_mutex_start_proxy_lock() - Start lock acquisition for another task
  * @lock:		the rt_mutex to take
@@ -1755,6 +2375,34 @@ int __rt_mutex_start_proxy_lock(struct r
 	if (try_to_take_rt_mutex(lock, task, NULL))
 		return 1;
 
+#ifdef CONFIG_PREEMPT_RT
+	/*
+	 * In PREEMPT_RT there's an added race.
+	 * If the task, that we are about to requeue, times out,
+	 * it can set the PI_WAKEUP_INPROGRESS. This tells the requeue
+	 * to skip this task. But right after the task sets
+	 * its pi_blocked_on to PI_WAKEUP_INPROGRESS it can then
+	 * block on the spin_lock(&hb->lock), which in RT is an rtmutex.
+	 * This will replace the PI_WAKEUP_INPROGRESS with the actual
+	 * lock that it blocks on. We *must not* place this task
+	 * on this proxy lock in that case.
+	 *
+	 * To prevent this race, we first take the task's pi_lock
+	 * and check if it has updated its pi_blocked_on. If it has,
+	 * we assume that it woke up and we return -EAGAIN.
+	 * Otherwise, we set the task's pi_blocked_on to
+	 * PI_REQUEUE_INPROGRESS, so that if the task is waking up
+	 * it will know that we are in the process of requeuing it.
+	 */
+	raw_spin_lock(&task->pi_lock);
+	if (task->pi_blocked_on) {
+		raw_spin_unlock(&task->pi_lock);
+		return -EAGAIN;
+	}
+	task->pi_blocked_on = PI_REQUEUE_INPROGRESS;
+	raw_spin_unlock(&task->pi_lock);
+#endif
+
 	/* We enforce deadlock detection for futexes */
 	ret = task_blocks_on_rt_mutex(lock, waiter, task,
 				      RT_MUTEX_FULL_CHAINWALK);
@@ -1769,6 +2417,9 @@ int __rt_mutex_start_proxy_lock(struct r
 		ret = 0;
 	}
 
+	if (ret)
+		fixup_rt_mutex_blocked(lock);
+
 	debug_rt_mutex_print_deadlock(waiter);
 
 	return ret;
@@ -1854,12 +2505,15 @@ int rt_mutex_wait_proxy_lock(struct rt_m
 	raw_spin_lock_irq(&lock->wait_lock);
 	/* sleep on the mutex */
 	set_current_state(TASK_INTERRUPTIBLE);
-	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter);
+	ret = __rt_mutex_slowlock(lock, TASK_INTERRUPTIBLE, to, waiter, NULL);
 	/*
 	 * try_to_take_rt_mutex() sets the waiter bit unconditionally. We might
 	 * have to fix that up.
 	 */
 	fixup_rt_mutex_waiters(lock);
+	if (ret)
+		fixup_rt_mutex_blocked(lock);
+
 	raw_spin_unlock_irq(&lock->wait_lock);
 
 	return ret;
@@ -1921,3 +2575,99 @@ bool rt_mutex_cleanup_proxy_lock(struct
 
 	return cleanup;
 }
+
+static inline int
+ww_mutex_deadlock_injection(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+#ifdef CONFIG_DEBUG_WW_MUTEX_SLOWPATH
+	unsigned tmp;
+
+	if (ctx->deadlock_inject_countdown-- == 0) {
+		tmp = ctx->deadlock_inject_interval;
+		if (tmp > UINT_MAX/4)
+			tmp = UINT_MAX;
+		else
+			tmp = tmp*2 + tmp + tmp/2;
+
+		ctx->deadlock_inject_interval = tmp;
+		ctx->deadlock_inject_countdown = tmp;
+		ctx->contending_lock = lock;
+
+		ww_mutex_unlock(lock);
+
+		return -EDEADLK;
+	}
+#endif
+
+	return 0;
+}
+
+#ifdef CONFIG_PREEMPT_RT
+int __sched
+ww_mutex_lock_interruptible(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	int ret;
+
+	might_sleep();
+
+	mutex_acquire_nest(&lock->base.dep_map, 0, 0,
+			   ctx ? &ctx->dep_map : NULL, _RET_IP_);
+	ret = rt_mutex_slowlock(&lock->base.lock, TASK_INTERRUPTIBLE, NULL, 0,
+				ctx);
+	if (ret)
+		mutex_release(&lock->base.dep_map, 1, _RET_IP_);
+	else if (!ret && ctx && ctx->acquired > 1)
+		return ww_mutex_deadlock_injection(lock, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ww_mutex_lock_interruptible);
+
+int __sched
+ww_mutex_lock(struct ww_mutex *lock, struct ww_acquire_ctx *ctx)
+{
+	int ret;
+
+	might_sleep();
+
+	mutex_acquire_nest(&lock->base.dep_map, 0, 0,
+			   ctx ? &ctx->dep_map : NULL, _RET_IP_);
+	ret = rt_mutex_slowlock(&lock->base.lock, TASK_UNINTERRUPTIBLE, NULL, 0,
+				ctx);
+	if (ret)
+		mutex_release(&lock->base.dep_map, 1, _RET_IP_);
+	else if (!ret && ctx && ctx->acquired > 1)
+		return ww_mutex_deadlock_injection(lock, ctx);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ww_mutex_lock);
+
+void __sched ww_mutex_unlock(struct ww_mutex *lock)
+{
+	int nest = !!lock->ctx;
+
+	/*
+	 * The unlocking fastpath is the 0->1 transition from 'locked'
+	 * into 'unlocked' state:
+	 */
+	if (nest) {
+#ifdef CONFIG_DEBUG_MUTEXES
+		DEBUG_LOCKS_WARN_ON(!lock->ctx->acquired);
+#endif
+		if (lock->ctx->acquired > 0)
+			lock->ctx->acquired--;
+		lock->ctx = NULL;
+	}
+
+	mutex_release(&lock->base.dep_map, nest, _RET_IP_);
+	__rt_mutex_unlock(&lock->base.lock);
+}
+EXPORT_SYMBOL(ww_mutex_unlock);
+
+int __rt_mutex_owner_current(struct rt_mutex *lock)
+{
+	return rt_mutex_owner(lock) == current;
+}
+EXPORT_SYMBOL(__rt_mutex_owner_current);
+#endif
Index: linux-5.4.5-rt3/kernel/locking/rtmutex_common.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/rtmutex_common.h
+++ linux-5.4.5-rt3/kernel/locking/rtmutex_common.h
@@ -15,6 +15,7 @@
 
 #include <linux/rtmutex.h>
 #include <linux/sched/wake_q.h>
+#include <linux/sched/debug.h>
 
 /*
  * This is the control structure for tasks blocked on a rt_mutex,
@@ -29,6 +30,7 @@ struct rt_mutex_waiter {
 	struct rb_node          pi_tree_entry;
 	struct task_struct	*task;
 	struct rt_mutex		*lock;
+	bool			savestate;
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 	unsigned long		ip;
 	struct pid		*deadlock_task_pid;
@@ -130,12 +132,15 @@ enum rtmutex_chainwalk {
 /*
  * PI-futex support (proxy locking functions, etc.):
  */
+#define PI_WAKEUP_INPROGRESS	((struct rt_mutex_waiter *) 1)
+#define PI_REQUEUE_INPROGRESS	((struct rt_mutex_waiter *) 2)
+
 extern struct task_struct *rt_mutex_next_owner(struct rt_mutex *lock);
 extern void rt_mutex_init_proxy_locked(struct rt_mutex *lock,
 				       struct task_struct *proxy_owner);
 extern void rt_mutex_proxy_unlock(struct rt_mutex *lock,
 				  struct task_struct *proxy_owner);
-extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter);
+extern void rt_mutex_init_waiter(struct rt_mutex_waiter *waiter, bool savetate);
 extern int __rt_mutex_start_proxy_lock(struct rt_mutex *lock,
 				     struct rt_mutex_waiter *waiter,
 				     struct task_struct *task);
@@ -153,9 +158,27 @@ extern int __rt_mutex_futex_trylock(stru
 
 extern void rt_mutex_futex_unlock(struct rt_mutex *lock);
 extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
-				 struct wake_q_head *wqh);
+				 struct wake_q_head *wqh,
+				 struct wake_q_head *wq_sleeper);
+
+extern void rt_mutex_postunlock(struct wake_q_head *wake_q,
+				struct wake_q_head *wake_sleeper_q);
+
+/* RW semaphore special interface */
+struct ww_acquire_ctx;
 
-extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+extern int __rt_mutex_lock_state(struct rt_mutex *lock, int state);
+extern int __rt_mutex_trylock(struct rt_mutex *lock);
+extern void __rt_mutex_unlock(struct rt_mutex *lock);
+int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+				     struct hrtimer_sleeper *timeout,
+				     enum rtmutex_chainwalk chwalk,
+				     struct ww_acquire_ctx *ww_ctx,
+				     struct rt_mutex_waiter *waiter);
+void __sched rt_spin_lock_slowlock_locked(struct rt_mutex *lock,
+					  struct rt_mutex_waiter *waiter,
+					  unsigned long flags);
+void __sched rt_spin_lock_slowunlock(struct rt_mutex *lock);
 
 #ifdef CONFIG_DEBUG_RT_MUTEXES
 # include "rtmutex-debug.h"
Index: linux-5.4.5-rt3/kernel/locking/rwlock-rt.c
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/kernel/locking/rwlock-rt.c
@@ -0,0 +1,384 @@
+/*
+ */
+#include <linux/sched/debug.h>
+#include <linux/export.h>
+
+#include "rtmutex_common.h"
+#include <linux/rwlock_types_rt.h>
+
+/*
+ * RT-specific reader/writer locks
+ *
+ * write_lock()
+ *  1) Lock lock->rtmutex
+ *  2) Remove the reader BIAS to force readers into the slow path
+ *  3) Wait until all readers have left the critical region
+ *  4) Mark it write locked
+ *
+ * write_unlock()
+ *  1) Remove the write locked marker
+ *  2) Set the reader BIAS so readers can use the fast path again
+ *  3) Unlock lock->rtmutex to release blocked readers
+ *
+ * read_lock()
+ *  1) Try fast path acquisition (reader BIAS is set)
+ *  2) Take lock->rtmutex.wait_lock which protects the writelocked flag
+ *  3) If !writelocked, acquire it for read
+ *  4) If writelocked, block on lock->rtmutex
+ *  5) unlock lock->rtmutex, goto 1)
+ *
+ * read_unlock()
+ *  1) Try fast path release (reader count != 1)
+ *  2) Wake the writer waiting in write_lock()#3
+ *
+ * read_lock()#3 has the consequence, that rw locks on RT are not writer
+ * fair, but writers, which should be avoided in RT tasks (think tasklist
+ * lock), are subject to the rtmutex priority/DL inheritance mechanism.
+ *
+ * It's possible to make the rw locks writer fair by keeping a list of
+ * active readers. A blocked writer would force all newly incoming readers
+ * to block on the rtmutex, but the rtmutex would have to be proxy locked
+ * for one reader after the other. We can't use multi-reader inheritance
+ * because there is no way to support that with
+ * SCHED_DEADLINE. Implementing the one by one reader boosting/handover
+ * mechanism is a major surgery for a very dubious value.
+ *
+ * The risk of writer starvation is there, but the pathological use cases
+ * which trigger it are not necessarily the typical RT workloads.
+ */
+
+void __rwlock_biased_rt_init(struct rt_rw_lock *lock, const char *name,
+			     struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held semaphore:
+	 */
+	debug_check_no_locks_freed((void *)lock, sizeof(*lock));
+	lockdep_init_map(&lock->dep_map, name, key, 0);
+#endif
+	atomic_set(&lock->readers, READER_BIAS);
+	rt_mutex_init(&lock->rtmutex);
+	lock->rtmutex.save_state = 1;
+}
+
+int __read_rt_trylock(struct rt_rw_lock *lock)
+{
+	int r, old;
+
+	/*
+	 * Increment reader count, if lock->readers < 0, i.e. READER_BIAS is
+	 * set.
+	 */
+	for (r = atomic_read(&lock->readers); r < 0;) {
+		old = atomic_cmpxchg(&lock->readers, r, r + 1);
+		if (likely(old == r))
+			return 1;
+		r = old;
+	}
+	return 0;
+}
+
+void __sched __read_rt_lock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	struct rt_mutex_waiter waiter;
+	unsigned long flags;
+
+	if (__read_rt_trylock(lock))
+		return;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	/*
+	 * Allow readers as long as the writer has not completely
+	 * acquired the semaphore for write.
+	 */
+	if (atomic_read(&lock->readers) != WRITER_BIAS) {
+		atomic_inc(&lock->readers);
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+		return;
+	}
+
+	/*
+	 * Call into the slow lock path with the rtmutex->wait_lock
+	 * held, so this can't result in the following race:
+	 *
+	 * Reader1		Reader2		Writer
+	 *			read_lock()
+	 *					write_lock()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * read_lock()
+	 * unlock(m->wait_lock)
+	 *			read_unlock()
+	 *			swake()
+	 *					lock(m->wait_lock)
+	 *					lock->writelocked=true
+	 *					unlock(m->wait_lock)
+	 *
+	 *					write_unlock()
+	 *					lock->writelocked=false
+	 *					rtmutex_unlock(m)
+	 *			read_lock()
+	 *					write_lock()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * rtmutex_lock(m)
+	 *
+	 * That would put Reader1 behind the writer waiting on
+	 * Reader2 to call read_unlock() which might be unbound.
+	 */
+	rt_mutex_init_waiter(&waiter, true);
+	rt_spin_lock_slowlock_locked(m, &waiter, flags);
+	/*
+	 * The slowlock() above is guaranteed to return with the rtmutex is
+	 * now held, so there can't be a writer active. Increment the reader
+	 * count and immediately drop the rtmutex again.
+	 */
+	atomic_inc(&lock->readers);
+	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+	rt_spin_lock_slowunlock(m);
+
+	debug_rt_mutex_free_waiter(&waiter);
+}
+
+void __read_rt_unlock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	struct task_struct *tsk;
+
+	/*
+	 * sem->readers can only hit 0 when a writer is waiting for the
+	 * active readers to leave the critical region.
+	 */
+	if (!atomic_dec_and_test(&lock->readers))
+		return;
+
+	raw_spin_lock_irq(&m->wait_lock);
+	/*
+	 * Wake the writer, i.e. the rtmutex owner. It might release the
+	 * rtmutex concurrently in the fast path, but to clean up the rw
+	 * lock it needs to acquire m->wait_lock. The worst case which can
+	 * happen is a spurious wakeup.
+	 */
+	tsk = rt_mutex_owner(m);
+	if (tsk)
+		wake_up_process(tsk);
+
+	raw_spin_unlock_irq(&m->wait_lock);
+}
+
+static void __write_unlock_common(struct rt_rw_lock *lock, int bias,
+				  unsigned long flags)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+
+	atomic_add(READER_BIAS - bias, &lock->readers);
+	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+	rt_spin_lock_slowunlock(m);
+}
+
+void __sched __write_rt_lock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	struct task_struct *self = current;
+	unsigned long flags;
+
+	/* Take the rtmutex as a first step */
+	__rt_spin_lock(m);
+
+	/* Force readers into slow path */
+	atomic_sub(READER_BIAS, &lock->readers);
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+
+	raw_spin_lock(&self->pi_lock);
+	self->saved_state = self->state;
+	__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+	raw_spin_unlock(&self->pi_lock);
+
+	for (;;) {
+		/* Have all readers left the critical region? */
+		if (!atomic_read(&lock->readers)) {
+			atomic_set(&lock->readers, WRITER_BIAS);
+			raw_spin_lock(&self->pi_lock);
+			__set_current_state_no_track(self->saved_state);
+			self->saved_state = TASK_RUNNING;
+			raw_spin_unlock(&self->pi_lock);
+			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+			return;
+		}
+
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+
+		if (atomic_read(&lock->readers) != 0)
+			schedule();
+
+		raw_spin_lock_irqsave(&m->wait_lock, flags);
+
+		raw_spin_lock(&self->pi_lock);
+		__set_current_state_no_track(TASK_UNINTERRUPTIBLE);
+		raw_spin_unlock(&self->pi_lock);
+	}
+}
+
+int __write_rt_trylock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	unsigned long flags;
+
+	if (!__rt_mutex_trylock(m))
+		return 0;
+
+	atomic_sub(READER_BIAS, &lock->readers);
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	if (!atomic_read(&lock->readers)) {
+		atomic_set(&lock->readers, WRITER_BIAS);
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+		return 1;
+	}
+	__write_unlock_common(lock, 0, flags);
+	return 0;
+}
+
+void __write_rt_unlock(struct rt_rw_lock *lock)
+{
+	struct rt_mutex *m = &lock->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	__write_unlock_common(lock, WRITER_BIAS, flags);
+}
+
+/* Map the reader biased implementation */
+static inline int do_read_rt_trylock(rwlock_t *rwlock)
+{
+	return __read_rt_trylock(rwlock);
+}
+
+static inline int do_write_rt_trylock(rwlock_t *rwlock)
+{
+	return __write_rt_trylock(rwlock);
+}
+
+static inline void do_read_rt_lock(rwlock_t *rwlock)
+{
+	__read_rt_lock(rwlock);
+}
+
+static inline void do_write_rt_lock(rwlock_t *rwlock)
+{
+	__write_rt_lock(rwlock);
+}
+
+static inline void do_read_rt_unlock(rwlock_t *rwlock)
+{
+	__read_rt_unlock(rwlock);
+}
+
+static inline void do_write_rt_unlock(rwlock_t *rwlock)
+{
+	__write_rt_unlock(rwlock);
+}
+
+static inline void do_rwlock_rt_init(rwlock_t *rwlock, const char *name,
+				     struct lock_class_key *key)
+{
+	__rwlock_biased_rt_init(rwlock, name, key);
+}
+
+int __lockfunc rt_read_can_lock(rwlock_t *rwlock)
+{
+	return  atomic_read(&rwlock->readers) < 0;
+}
+
+int __lockfunc rt_write_can_lock(rwlock_t *rwlock)
+{
+	return atomic_read(&rwlock->readers) == READER_BIAS;
+}
+
+/*
+ * The common functions which get wrapped into the rwlock API.
+ */
+int __lockfunc rt_read_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	sleeping_lock_inc();
+	migrate_disable();
+	ret = do_read_rt_trylock(rwlock);
+	if (ret) {
+		rwlock_acquire_read(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+	} else {
+		migrate_enable();
+		sleeping_lock_dec();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_read_trylock);
+
+int __lockfunc rt_write_trylock(rwlock_t *rwlock)
+{
+	int ret;
+
+	sleeping_lock_inc();
+	migrate_disable();
+	ret = do_write_rt_trylock(rwlock);
+	if (ret) {
+		rwlock_acquire(&rwlock->dep_map, 0, 1, _RET_IP_);
+		rcu_read_lock();
+	} else {
+		migrate_enable();
+		sleeping_lock_dec();
+	}
+	return ret;
+}
+EXPORT_SYMBOL(rt_write_trylock);
+
+void __lockfunc rt_read_lock(rwlock_t *rwlock)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	rwlock_acquire_read(&rwlock->dep_map, 0, 0, _RET_IP_);
+	do_read_rt_lock(rwlock);
+}
+EXPORT_SYMBOL(rt_read_lock);
+
+void __lockfunc rt_write_lock(rwlock_t *rwlock)
+{
+	sleeping_lock_inc();
+	rcu_read_lock();
+	migrate_disable();
+	rwlock_acquire(&rwlock->dep_map, 0, 0, _RET_IP_);
+	do_write_rt_lock(rwlock);
+}
+EXPORT_SYMBOL(rt_write_lock);
+
+void __lockfunc rt_read_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+	do_read_rt_unlock(rwlock);
+	migrate_enable();
+	rcu_read_unlock();
+	sleeping_lock_dec();
+}
+EXPORT_SYMBOL(rt_read_unlock);
+
+void __lockfunc rt_write_unlock(rwlock_t *rwlock)
+{
+	rwlock_release(&rwlock->dep_map, 1, _RET_IP_);
+	do_write_rt_unlock(rwlock);
+	migrate_enable();
+	rcu_read_unlock();
+	sleeping_lock_dec();
+}
+EXPORT_SYMBOL(rt_write_unlock);
+
+void __rt_rwlock_init(rwlock_t *rwlock, char *name, struct lock_class_key *key)
+{
+	do_rwlock_rt_init(rwlock, name, key);
+}
+EXPORT_SYMBOL(__rt_rwlock_init);
Index: linux-5.4.5-rt3/kernel/locking/rwsem-rt.c
===================================================================
--- /dev/null
+++ linux-5.4.5-rt3/kernel/locking/rwsem-rt.c
@@ -0,0 +1,302 @@
+/*
+ */
+#include <linux/blkdev.h>
+#include <linux/rwsem.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/signal.h>
+#include <linux/export.h>
+
+#include "rtmutex_common.h"
+
+/*
+ * RT-specific reader/writer semaphores
+ *
+ * down_write()
+ *  1) Lock sem->rtmutex
+ *  2) Remove the reader BIAS to force readers into the slow path
+ *  3) Wait until all readers have left the critical region
+ *  4) Mark it write locked
+ *
+ * up_write()
+ *  1) Remove the write locked marker
+ *  2) Set the reader BIAS so readers can use the fast path again
+ *  3) Unlock sem->rtmutex to release blocked readers
+ *
+ * down_read()
+ *  1) Try fast path acquisition (reader BIAS is set)
+ *  2) Take sem->rtmutex.wait_lock which protects the writelocked flag
+ *  3) If !writelocked, acquire it for read
+ *  4) If writelocked, block on sem->rtmutex
+ *  5) unlock sem->rtmutex, goto 1)
+ *
+ * up_read()
+ *  1) Try fast path release (reader count != 1)
+ *  2) Wake the writer waiting in down_write()#3
+ *
+ * down_read()#3 has the consequence, that rw semaphores on RT are not writer
+ * fair, but writers, which should be avoided in RT tasks (think mmap_sem),
+ * are subject to the rtmutex priority/DL inheritance mechanism.
+ *
+ * It's possible to make the rw semaphores writer fair by keeping a list of
+ * active readers. A blocked writer would force all newly incoming readers to
+ * block on the rtmutex, but the rtmutex would have to be proxy locked for one
+ * reader after the other. We can't use multi-reader inheritance because there
+ * is no way to support that with SCHED_DEADLINE. Implementing the one by one
+ * reader boosting/handover mechanism is a major surgery for a very dubious
+ * value.
+ *
+ * The risk of writer starvation is there, but the pathological use cases
+ * which trigger it are not necessarily the typical RT workloads.
+ */
+
+void __rwsem_init(struct rw_semaphore *sem, const char *name,
+		  struct lock_class_key *key)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+	/*
+	 * Make sure we are not reinitializing a held semaphore:
+	 */
+	debug_check_no_locks_freed((void *)sem, sizeof(*sem));
+	lockdep_init_map(&sem->dep_map, name, key, 0);
+#endif
+	atomic_set(&sem->readers, READER_BIAS);
+}
+EXPORT_SYMBOL(__rwsem_init);
+
+int __down_read_trylock(struct rw_semaphore *sem)
+{
+	int r, old;
+
+	/*
+	 * Increment reader count, if sem->readers < 0, i.e. READER_BIAS is
+	 * set.
+	 */
+	for (r = atomic_read(&sem->readers); r < 0;) {
+		old = atomic_cmpxchg(&sem->readers, r, r + 1);
+		if (likely(old == r))
+			return 1;
+		r = old;
+	}
+	return 0;
+}
+
+static int __sched __down_read_common(struct rw_semaphore *sem, int state)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	struct rt_mutex_waiter waiter;
+	int ret;
+
+	if (__down_read_trylock(sem))
+		return 0;
+	/*
+	 * If rt_mutex blocks, the function sched_submit_work will not call
+	 * blk_schedule_flush_plug (because tsk_is_pi_blocked would be true).
+	 * We must call blk_schedule_flush_plug here, if we don't call it,
+	 * a deadlock in I/O may happen.
+	 */
+	if (unlikely(blk_needs_flush_plug(current)))
+		blk_schedule_flush_plug(current);
+
+	might_sleep();
+	raw_spin_lock_irq(&m->wait_lock);
+	/*
+	 * Allow readers as long as the writer has not completely
+	 * acquired the semaphore for write.
+	 */
+	if (atomic_read(&sem->readers) != WRITER_BIAS) {
+		atomic_inc(&sem->readers);
+		raw_spin_unlock_irq(&m->wait_lock);
+		return 0;
+	}
+
+	/*
+	 * Call into the slow lock path with the rtmutex->wait_lock
+	 * held, so this can't result in the following race:
+	 *
+	 * Reader1		Reader2		Writer
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * down_read()
+	 * unlock(m->wait_lock)
+	 *			up_read()
+	 *			swake()
+	 *					lock(m->wait_lock)
+	 *					sem->writelocked=true
+	 *					unlock(m->wait_lock)
+	 *
+	 *					up_write()
+	 *					sem->writelocked=false
+	 *					rtmutex_unlock(m)
+	 *			down_read()
+	 *					down_write()
+	 *					rtmutex_lock(m)
+	 *					swait()
+	 * rtmutex_lock(m)
+	 *
+	 * That would put Reader1 behind the writer waiting on
+	 * Reader2 to call up_read() which might be unbound.
+	 */
+	rt_mutex_init_waiter(&waiter, false);
+	ret = rt_mutex_slowlock_locked(m, state, NULL, RT_MUTEX_MIN_CHAINWALK,
+				       NULL, &waiter);
+	/*
+	 * The slowlock() above is guaranteed to return with the rtmutex (for
+	 * ret = 0) is now held, so there can't be a writer active. Increment
+	 * the reader count and immediately drop the rtmutex again.
+	 * For ret != 0 we don't hold the rtmutex and need unlock the wait_lock.
+	 * We don't own the lock then.
+	 */
+	if (!ret)
+		atomic_inc(&sem->readers);
+	raw_spin_unlock_irq(&m->wait_lock);
+	if (!ret)
+		__rt_mutex_unlock(m);
+
+	debug_rt_mutex_free_waiter(&waiter);
+	return ret;
+}
+
+void __down_read(struct rw_semaphore *sem)
+{
+	int ret;
+
+	ret = __down_read_common(sem, TASK_UNINTERRUPTIBLE);
+	WARN_ON_ONCE(ret);
+}
+
+int __down_read_killable(struct rw_semaphore *sem)
+{
+	int ret;
+
+	ret = __down_read_common(sem, TASK_KILLABLE);
+	if (likely(!ret))
+		return ret;
+	WARN_ONCE(ret != -EINTR, "Unexpected state: %d\n", ret);
+	return -EINTR;
+}
+
+void __up_read(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	struct task_struct *tsk;
+
+	/*
+	 * sem->readers can only hit 0 when a writer is waiting for the
+	 * active readers to leave the critical region.
+	 */
+	if (!atomic_dec_and_test(&sem->readers))
+		return;
+
+	might_sleep();
+	raw_spin_lock_irq(&m->wait_lock);
+	/*
+	 * Wake the writer, i.e. the rtmutex owner. It might release the
+	 * rtmutex concurrently in the fast path (due to a signal), but to
+	 * clean up the rwsem it needs to acquire m->wait_lock. The worst
+	 * case which can happen is a spurious wakeup.
+	 */
+	tsk = rt_mutex_owner(m);
+	if (tsk)
+		wake_up_process(tsk);
+
+	raw_spin_unlock_irq(&m->wait_lock);
+}
+
+static void __up_write_unlock(struct rw_semaphore *sem, int bias,
+			      unsigned long flags)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+
+	atomic_add(READER_BIAS - bias, &sem->readers);
+	raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+	__rt_mutex_unlock(m);
+}
+
+static int __sched __down_write_common(struct rw_semaphore *sem, int state)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	/* Take the rtmutex as a first step */
+	if (__rt_mutex_lock_state(m, state))
+		return -EINTR;
+
+	/* Force readers into slow path */
+	atomic_sub(READER_BIAS, &sem->readers);
+	might_sleep();
+
+	set_current_state(state);
+	for (;;) {
+		raw_spin_lock_irqsave(&m->wait_lock, flags);
+		/* Have all readers left the critical region? */
+		if (!atomic_read(&sem->readers)) {
+			atomic_set(&sem->readers, WRITER_BIAS);
+			__set_current_state(TASK_RUNNING);
+			raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+			return 0;
+		}
+
+		if (signal_pending_state(state, current)) {
+			__set_current_state(TASK_RUNNING);
+			__up_write_unlock(sem, 0, flags);
+			return -EINTR;
+		}
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+
+		if (atomic_read(&sem->readers) != 0) {
+			schedule();
+			set_current_state(state);
+		}
+	}
+}
+
+void __sched __down_write(struct rw_semaphore *sem)
+{
+	__down_write_common(sem, TASK_UNINTERRUPTIBLE);
+}
+
+int __sched __down_write_killable(struct rw_semaphore *sem)
+{
+	return __down_write_common(sem, TASK_KILLABLE);
+}
+
+int __down_write_trylock(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	if (!__rt_mutex_trylock(m))
+		return 0;
+
+	atomic_sub(READER_BIAS, &sem->readers);
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	if (!atomic_read(&sem->readers)) {
+		atomic_set(&sem->readers, WRITER_BIAS);
+		raw_spin_unlock_irqrestore(&m->wait_lock, flags);
+		return 1;
+	}
+	__up_write_unlock(sem, 0, flags);
+	return 0;
+}
+
+void __up_write(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	__up_write_unlock(sem, WRITER_BIAS, flags);
+}
+
+void __downgrade_write(struct rw_semaphore *sem)
+{
+	struct rt_mutex *m = &sem->rtmutex;
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&m->wait_lock, flags);
+	/* Release it and account current as reader */
+	__up_write_unlock(sem, WRITER_BIAS - 1, flags);
+}
Index: linux-5.4.5-rt3/kernel/locking/rwsem.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/rwsem.c
+++ linux-5.4.5-rt3/kernel/locking/rwsem.c
@@ -28,7 +28,7 @@
 #include <linux/rwsem.h>
 #include <linux/atomic.h>
 
-#include "rwsem.h"
+#ifndef CONFIG_PREEMPT_RT
 #include "lock_events.h"
 
 /*
@@ -660,8 +660,6 @@ static inline bool rwsem_can_spin_on_own
 	unsigned long flags;
 	bool ret = true;
 
-	BUILD_BUG_ON(!(RWSEM_OWNER_UNKNOWN & RWSEM_NONSPINNABLE));
-
 	if (need_resched()) {
 		lockevent_inc(rwsem_opt_fail);
 		return false;
@@ -1335,10 +1333,11 @@ static struct rw_semaphore *rwsem_downgr
 	return sem;
 }
 
+
 /*
  * lock for reading
  */
-inline void __down_read(struct rw_semaphore *sem)
+static inline void __down_read(struct rw_semaphore *sem)
 {
 	if (!rwsem_read_trylock(sem)) {
 		rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE);
@@ -1426,7 +1425,7 @@ static inline int __down_write_trylock(s
 /*
  * unlock after reading
  */
-inline void __up_read(struct rw_semaphore *sem)
+static inline void __up_read(struct rw_semaphore *sem)
 {
 	long tmp;
 
@@ -1485,6 +1484,7 @@ static inline void __downgrade_write(str
 	if (tmp & RWSEM_FLAG_WAITERS)
 		rwsem_downgrade_wake(sem);
 }
+#endif
 
 /*
  * lock for reading
@@ -1616,6 +1616,7 @@ void _down_write_nest_lock(struct rw_sem
 }
 EXPORT_SYMBOL(_down_write_nest_lock);
 
+#ifndef CONFIG_PREEMPT_RT
 void down_read_non_owner(struct rw_semaphore *sem)
 {
 	might_sleep();
@@ -1623,6 +1624,7 @@ void down_read_non_owner(struct rw_semap
 	__rwsem_set_reader_owned(sem, NULL);
 }
 EXPORT_SYMBOL(down_read_non_owner);
+#endif
 
 void down_write_nested(struct rw_semaphore *sem, int subclass)
 {
@@ -1647,11 +1649,13 @@ int __sched down_write_killable_nested(s
 }
 EXPORT_SYMBOL(down_write_killable_nested);
 
+#ifndef CONFIG_PREEMPT_RT
 void up_read_non_owner(struct rw_semaphore *sem)
 {
 	DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);
 	__up_read(sem);
 }
 EXPORT_SYMBOL(up_read_non_owner);
+#endif
 
 #endif
Index: linux-5.4.5-rt3/kernel/locking/rwsem.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/rwsem.h
+++ linux-5.4.5-rt3/kernel/locking/rwsem.h
@@ -1,10 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-
-#ifndef __INTERNAL_RWSEM_H
-#define __INTERNAL_RWSEM_H
-#include <linux/rwsem.h>
-
-extern void __down_read(struct rw_semaphore *sem);
-extern void __up_read(struct rw_semaphore *sem);
-
-#endif /* __INTERNAL_RWSEM_H */
Index: linux-5.4.5-rt3/kernel/locking/spinlock.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/spinlock.c
+++ linux-5.4.5-rt3/kernel/locking/spinlock.c
@@ -124,8 +124,11 @@ void __lockfunc __raw_##op##_lock_bh(loc
  *         __[spin|read|write]_lock_bh()
  */
 BUILD_LOCK_OPS(spin, raw_spinlock);
+
+#ifndef CONFIG_PREEMPT_RT
 BUILD_LOCK_OPS(read, rwlock);
 BUILD_LOCK_OPS(write, rwlock);
+#endif
 
 #endif
 
@@ -209,6 +212,8 @@ void __lockfunc _raw_spin_unlock_bh(raw_
 EXPORT_SYMBOL(_raw_spin_unlock_bh);
 #endif
 
+#ifndef CONFIG_PREEMPT_RT
+
 #ifndef CONFIG_INLINE_READ_TRYLOCK
 int __lockfunc _raw_read_trylock(rwlock_t *lock)
 {
@@ -353,6 +358,8 @@ void __lockfunc _raw_write_unlock_bh(rwl
 EXPORT_SYMBOL(_raw_write_unlock_bh);
 #endif
 
+#endif /* !PREEMPT_RT */
+
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 
 void __lockfunc _raw_spin_lock_nested(raw_spinlock_t *lock, int subclass)
Index: linux-5.4.5-rt3/kernel/locking/spinlock_debug.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/locking/spinlock_debug.c
+++ linux-5.4.5-rt3/kernel/locking/spinlock_debug.c
@@ -31,6 +31,7 @@ void __raw_spin_lock_init(raw_spinlock_t
 
 EXPORT_SYMBOL(__raw_spin_lock_init);
 
+#ifndef CONFIG_PREEMPT_RT
 void __rwlock_init(rwlock_t *lock, const char *name,
 		   struct lock_class_key *key)
 {
@@ -48,6 +49,7 @@ void __rwlock_init(rwlock_t *lock, const
 }
 
 EXPORT_SYMBOL(__rwlock_init);
+#endif
 
 static void spin_dump(raw_spinlock_t *lock, const char *msg)
 {
@@ -139,6 +141,7 @@ void do_raw_spin_unlock(raw_spinlock_t *
 	arch_spin_unlock(&lock->raw_lock);
 }
 
+#ifndef CONFIG_PREEMPT_RT
 static void rwlock_bug(rwlock_t *lock, const char *msg)
 {
 	if (!debug_locks_off())
@@ -228,3 +231,5 @@ void do_raw_write_unlock(rwlock_t *lock)
 	debug_write_unlock(lock);
 	arch_write_unlock(&lock->raw_lock);
 }
+
+#endif
Index: linux-5.4.5-rt3/kernel/panic.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/panic.c
+++ linux-5.4.5-rt3/kernel/panic.c
@@ -237,7 +237,6 @@ void panic(const char *fmt, ...)
 	 * Bypass the panic_cpu check and call __crash_kexec directly.
 	 */
 	if (!_crash_kexec_post_notifiers) {
-		printk_safe_flush_on_panic();
 		__crash_kexec(NULL);
 
 		/*
@@ -261,8 +260,6 @@ void panic(const char *fmt, ...)
 	 */
 	atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
 
-	/* Call flush even twice. It tries harder with a single online CPU */
-	printk_safe_flush_on_panic();
 	kmsg_dump(KMSG_DUMP_PANIC);
 
 	/*
@@ -524,9 +521,11 @@ static u64 oops_id;
 
 static int init_oops_id(void)
 {
+#ifndef CONFIG_PREEMPT_RT
 	if (!oops_id)
 		get_random_bytes(&oops_id, sizeof(oops_id));
 	else
+#endif
 		oops_id++;
 
 	return 0;
Index: linux-5.4.5-rt3/kernel/power/hibernate.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/power/hibernate.c
+++ linux-5.4.5-rt3/kernel/power/hibernate.c
@@ -689,6 +689,10 @@ static int load_image_and_restore(void)
 	return error;
 }
 
+#ifndef CONFIG_SUSPEND
+bool pm_in_action;
+#endif
+
 /**
  * hibernate - Carry out system hibernation, including saving the image.
  */
@@ -702,6 +706,8 @@ int hibernate(void)
 		return -EPERM;
 	}
 
+	pm_in_action = true;
+
 	lock_system_sleep();
 	/* The snapshot device should not be opened while we're running */
 	if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
@@ -778,6 +784,7 @@ int hibernate(void)
 	atomic_inc(&snapshot_device_available);
  Unlock:
 	unlock_system_sleep();
+	pm_in_action = false;
 	pr_info("hibernation exit\n");
 
 	return error;
Index: linux-5.4.5-rt3/kernel/power/suspend.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/power/suspend.c
+++ linux-5.4.5-rt3/kernel/power/suspend.c
@@ -594,6 +594,8 @@ static int enter_state(suspend_state_t s
 	return error;
 }
 
+bool pm_in_action;
+
 /**
  * pm_suspend - Externally visible function for suspending the system.
  * @state: System sleep state to enter.
@@ -608,6 +610,7 @@ int pm_suspend(suspend_state_t state)
 	if (state <= PM_SUSPEND_ON || state >= PM_SUSPEND_MAX)
 		return -EINVAL;
 
+	pm_in_action = true;
 	pr_info("suspend entry (%s)\n", mem_sleep_labels[state]);
 	error = enter_state(state);
 	if (error) {
@@ -617,6 +620,7 @@ int pm_suspend(suspend_state_t state)
 		suspend_stats.success++;
 	}
 	pr_info("suspend exit\n");
+	pm_in_action = false;
 	return error;
 }
 EXPORT_SYMBOL(pm_suspend);
Index: linux-5.4.5-rt3/kernel/printk/Makefile
===================================================================
--- linux-5.4.5-rt3.orig/kernel/printk/Makefile
+++ linux-5.4.5-rt3/kernel/printk/Makefile
@@ -1,4 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-y	= printk.o
-obj-$(CONFIG_PRINTK)	+= printk_safe.o
 obj-$(CONFIG_A11Y_BRAILLE_CONSOLE)	+= braille.o
Index: linux-5.4.5-rt3/kernel/printk/internal.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/printk/internal.h
+++ /dev/null
@@ -1,67 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-/*
- * internal.h - printk internal definitions
- */
-#include <linux/percpu.h>
-
-#ifdef CONFIG_PRINTK
-
-#define PRINTK_SAFE_CONTEXT_MASK	 0x3fffffff
-#define PRINTK_NMI_DIRECT_CONTEXT_MASK	 0x40000000
-#define PRINTK_NMI_CONTEXT_MASK		 0x80000000
-
-extern raw_spinlock_t logbuf_lock;
-
-__printf(5, 0)
-int vprintk_store(int facility, int level,
-		  const char *dict, size_t dictlen,
-		  const char *fmt, va_list args);
-
-__printf(1, 0) int vprintk_default(const char *fmt, va_list args);
-__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args);
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args);
-void __printk_safe_enter(void);
-void __printk_safe_exit(void);
-
-#define printk_safe_enter_irqsave(flags)	\
-	do {					\
-		local_irq_save(flags);		\
-		__printk_safe_enter();		\
-	} while (0)
-
-#define printk_safe_exit_irqrestore(flags)	\
-	do {					\
-		__printk_safe_exit();		\
-		local_irq_restore(flags);	\
-	} while (0)
-
-#define printk_safe_enter_irq()		\
-	do {					\
-		local_irq_disable();		\
-		__printk_safe_enter();		\
-	} while (0)
-
-#define printk_safe_exit_irq()			\
-	do {					\
-		__printk_safe_exit();		\
-		local_irq_enable();		\
-	} while (0)
-
-void defer_console_output(void);
-
-#else
-
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args) { return 0; }
-
-/*
- * In !PRINTK builds we still export logbuf_lock spin_lock, console_sem
- * semaphore and some of console functions (console_unlock()/etc.), so
- * printk-safe must preserve the existing local IRQ guarantees.
- */
-#define printk_safe_enter_irqsave(flags) local_irq_save(flags)
-#define printk_safe_exit_irqrestore(flags) local_irq_restore(flags)
-
-#define printk_safe_enter_irq() local_irq_disable()
-#define printk_safe_exit_irq() local_irq_enable()
-
-#endif /* CONFIG_PRINTK */
Index: linux-5.4.5-rt3/kernel/printk/printk.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/printk/printk.c
+++ linux-5.4.5-rt3/kernel/printk/printk.c
@@ -45,6 +45,9 @@
 #include <linux/irq_work.h>
 #include <linux/ctype.h>
 #include <linux/uio.h>
+#include <linux/kthread.h>
+#include <linux/clocksource.h>
+#include <linux/printk_ringbuffer.h>
 #include <linux/sched/clock.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
@@ -58,13 +61,13 @@
 
 #include "console_cmdline.h"
 #include "braille.h"
-#include "internal.h"
 
-int console_printk[4] = {
+int console_printk[5] = {
 	CONSOLE_LOGLEVEL_DEFAULT,	/* console_loglevel */
 	MESSAGE_LOGLEVEL_DEFAULT,	/* default_message_loglevel */
 	CONSOLE_LOGLEVEL_MIN,		/* minimum_console_loglevel */
 	CONSOLE_LOGLEVEL_DEFAULT,	/* default_console_loglevel */
+	CONSOLE_LOGLEVEL_EMERGENCY,	/* emergency_console_loglevel */
 };
 EXPORT_SYMBOL_GPL(console_printk);
 
@@ -225,19 +228,7 @@ static int nr_ext_console_drivers;
 
 static int __down_trylock_console_sem(unsigned long ip)
 {
-	int lock_failed;
-	unsigned long flags;
-
-	/*
-	 * Here and in __up_console_sem() we need to be in safe mode,
-	 * because spindump/WARN/etc from under console ->lock will
-	 * deadlock in printk()->down_trylock_console_sem() otherwise.
-	 */
-	printk_safe_enter_irqsave(flags);
-	lock_failed = down_trylock(&console_sem);
-	printk_safe_exit_irqrestore(flags);
-
-	if (lock_failed)
+	if (down_trylock(&console_sem))
 		return 1;
 	mutex_acquire(&console_lock_dep_map, 0, 1, ip);
 	return 0;
@@ -246,13 +237,9 @@ static int __down_trylock_console_sem(un
 
 static void __up_console_sem(unsigned long ip)
 {
-	unsigned long flags;
-
 	mutex_release(&console_lock_dep_map, 1, ip);
 
-	printk_safe_enter_irqsave(flags);
 	up(&console_sem);
-	printk_safe_exit_irqrestore(flags);
 }
 #define up_console_sem() __up_console_sem(_RET_IP_)
 
@@ -267,11 +254,6 @@ static void __up_console_sem(unsigned lo
 static int console_locked, console_suspended;
 
 /*
- * If exclusive_console is non-NULL then only this console is to be printed to.
- */
-static struct console *exclusive_console;
-
-/*
  *	Array of consoles built from command line options (console=)
  */
 
@@ -367,6 +349,7 @@ enum log_flags {
 
 struct printk_log {
 	u64 ts_nsec;		/* timestamp in nanoseconds */
+	u16 cpu;		/* cpu that generated record */
 	u16 len;		/* length of entire record */
 	u16 text_len;		/* length of text buffer */
 	u16 dict_len;		/* length of dictionary buffer */
@@ -382,65 +365,22 @@ __packed __aligned(4)
 #endif
 ;
 
-/*
- * The logbuf_lock protects kmsg buffer, indices, counters.  This can be taken
- * within the scheduler's rq lock. It must be released before calling
- * console_unlock() or anything else that might wake up a process.
- */
-DEFINE_RAW_SPINLOCK(logbuf_lock);
-
-/*
- * Helper macros to lock/unlock logbuf_lock and switch between
- * printk-safe/unsafe modes.
- */
-#define logbuf_lock_irq()				\
-	do {						\
-		printk_safe_enter_irq();		\
-		raw_spin_lock(&logbuf_lock);		\
-	} while (0)
-
-#define logbuf_unlock_irq()				\
-	do {						\
-		raw_spin_unlock(&logbuf_lock);		\
-		printk_safe_exit_irq();			\
-	} while (0)
-
-#define logbuf_lock_irqsave(flags)			\
-	do {						\
-		printk_safe_enter_irqsave(flags);	\
-		raw_spin_lock(&logbuf_lock);		\
-	} while (0)
-
-#define logbuf_unlock_irqrestore(flags)		\
-	do {						\
-		raw_spin_unlock(&logbuf_lock);		\
-		printk_safe_exit_irqrestore(flags);	\
-	} while (0)
+DECLARE_STATIC_PRINTKRB_CPULOCK(printk_cpulock);
 
 #ifdef CONFIG_PRINTK
-DECLARE_WAIT_QUEUE_HEAD(log_wait);
-/* the next printk record to read by syslog(READ) or /proc/kmsg */
+/* record buffer */
+DECLARE_STATIC_PRINTKRB(printk_rb, CONFIG_LOG_BUF_SHIFT, &printk_cpulock);
+
+static DEFINE_MUTEX(syslog_lock);
+DECLARE_STATIC_PRINTKRB_ITER(syslog_iter, &printk_rb);
+
+/* the last printk record to read by syslog(READ) or /proc/kmsg */
 static u64 syslog_seq;
-static u32 syslog_idx;
 static size_t syslog_partial;
 static bool syslog_time;
 
-/* index and sequence number of the first record stored in the buffer */
-static u64 log_first_seq;
-static u32 log_first_idx;
-
-/* index and sequence number of the next record to store in the buffer */
-static u64 log_next_seq;
-static u32 log_next_idx;
-
-/* the next printk record to write to the console */
-static u64 console_seq;
-static u32 console_idx;
-static u64 exclusive_console_stop_seq;
-
 /* the next printk record to read after the last 'clear' command */
 static u64 clear_seq;
-static u32 clear_idx;
 
 #ifdef CONFIG_PRINTK_CALLER
 #define PREFIX_MAX		48
@@ -452,24 +392,16 @@ static u32 clear_idx;
 #define LOG_LEVEL(v)		((v) & 0x07)
 #define LOG_FACILITY(v)		((v) >> 3 & 0xff)
 
-/* record buffer */
-#define LOG_ALIGN __alignof__(struct printk_log)
-#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
-#define LOG_BUF_LEN_MAX (u32)(1 << 31)
-static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
-static char *log_buf = __log_buf;
-static u32 log_buf_len = __LOG_BUF_LEN;
-
 /* Return log buffer address */
 char *log_buf_addr_get(void)
 {
-	return log_buf;
+	return printk_rb.buffer;
 }
 
 /* Return log buffer size */
 u32 log_buf_len_get(void)
 {
-	return log_buf_len;
+	return (1 << printk_rb.size_bits);
 }
 
 /* human readable text of the record */
@@ -484,180 +416,50 @@ static char *log_dict(const struct print
 	return (char *)msg + sizeof(struct printk_log) + msg->text_len;
 }
 
-/* get record by index; idx must point to valid msg */
-static struct printk_log *log_from_idx(u32 idx)
-{
-	struct printk_log *msg = (struct printk_log *)(log_buf + idx);
-
-	/*
-	 * A length == 0 record is the end of buffer marker. Wrap around and
-	 * read the message at the start of the buffer.
-	 */
-	if (!msg->len)
-		return (struct printk_log *)log_buf;
-	return msg;
-}
-
-/* get next record; idx must point to valid msg */
-static u32 log_next(u32 idx)
-{
-	struct printk_log *msg = (struct printk_log *)(log_buf + idx);
-
-	/* length == 0 indicates the end of the buffer; wrap */
-	/*
-	 * A length == 0 record is the end of buffer marker. Wrap around and
-	 * read the message at the start of the buffer as *this* one, and
-	 * return the one after that.
-	 */
-	if (!msg->len) {
-		msg = (struct printk_log *)log_buf;
-		return msg->len;
-	}
-	return idx + msg->len;
-}
-
-/*
- * Check whether there is enough free space for the given message.
- *
- * The same values of first_idx and next_idx mean that the buffer
- * is either empty or full.
- *
- * If the buffer is empty, we must respect the position of the indexes.
- * They cannot be reset to the beginning of the buffer.
- */
-static int logbuf_has_space(u32 msg_size, bool empty)
-{
-	u32 free;
-
-	if (log_next_idx > log_first_idx || empty)
-		free = max(log_buf_len - log_next_idx, log_first_idx);
-	else
-		free = log_first_idx - log_next_idx;
-
-	/*
-	 * We need space also for an empty header that signalizes wrapping
-	 * of the buffer.
-	 */
-	return free >= msg_size + sizeof(struct printk_log);
-}
-
-static int log_make_free_space(u32 msg_size)
-{
-	while (log_first_seq < log_next_seq &&
-	       !logbuf_has_space(msg_size, false)) {
-		/* drop old messages until we have enough contiguous space */
-		log_first_idx = log_next(log_first_idx);
-		log_first_seq++;
-	}
-
-	if (clear_seq < log_first_seq) {
-		clear_seq = log_first_seq;
-		clear_idx = log_first_idx;
-	}
-
-	/* sequence numbers are equal, so the log buffer is empty */
-	if (logbuf_has_space(msg_size, log_first_seq == log_next_seq))
-		return 0;
-
-	return -ENOMEM;
-}
-
-/* compute the message size including the padding bytes */
-static u32 msg_used_size(u16 text_len, u16 dict_len, u32 *pad_len)
-{
-	u32 size;
-
-	size = sizeof(struct printk_log) + text_len + dict_len;
-	*pad_len = (-size) & (LOG_ALIGN - 1);
-	size += *pad_len;
-
-	return size;
-}
-
-/*
- * Define how much of the log buffer we could take at maximum. The value
- * must be greater than two. Note that only half of the buffer is available
- * when the index points to the middle.
- */
-#define MAX_LOG_TAKE_PART 4
-static const char trunc_msg[] = "<truncated>";
-
-static u32 truncate_msg(u16 *text_len, u16 *trunc_msg_len,
-			u16 *dict_len, u32 *pad_len)
-{
-	/*
-	 * The message should not take the whole buffer. Otherwise, it might
-	 * get removed too soon.
-	 */
-	u32 max_text_len = log_buf_len / MAX_LOG_TAKE_PART;
-	if (*text_len > max_text_len)
-		*text_len = max_text_len;
-	/* enable the warning message */
-	*trunc_msg_len = strlen(trunc_msg);
-	/* disable the "dict" completely */
-	*dict_len = 0;
-	/* compute the size again, count also the warning message */
-	return msg_used_size(*text_len + *trunc_msg_len, 0, pad_len);
-}
+static void printk_emergency(char *buffer, int level, u64 ts_nsec, u16 cpu,
+			     char *text, u16 text_len);
 
 /* insert record into the buffer, discard old ones, update heads */
 static int log_store(u32 caller_id, int facility, int level,
-		     enum log_flags flags, u64 ts_nsec,
+		     enum log_flags flags, u64 ts_nsec, u16 cpu,
 		     const char *dict, u16 dict_len,
 		     const char *text, u16 text_len)
 {
 	struct printk_log *msg;
-	u32 size, pad_len;
-	u16 trunc_msg_len = 0;
-
-	/* number of '\0' padding bytes to next message */
-	size = msg_used_size(text_len, dict_len, &pad_len);
+	struct prb_handle h;
+	char *rbuf;
+	u32 size;
 
-	if (log_make_free_space(size)) {
-		/* truncate the message if it is too long for empty buffer */
-		size = truncate_msg(&text_len, &trunc_msg_len,
-				    &dict_len, &pad_len);
-		/* survive when the log buffer is too small for trunc_msg */
-		if (log_make_free_space(size))
-			return 0;
-	}
+	size = sizeof(*msg) + text_len + dict_len;
 
-	if (log_next_idx + size + sizeof(struct printk_log) > log_buf_len) {
+	rbuf = prb_reserve(&h, &printk_rb, size);
+	if (!rbuf) {
 		/*
-		 * This message + an additional empty header does not fit
-		 * at the end of the buffer. Add an empty header with len == 0
-		 * to signify a wrap around.
+		 * An emergency message would have been printed, but
+		 * it cannot be stored in the log.
 		 */
-		memset(log_buf + log_next_idx, 0, sizeof(struct printk_log));
-		log_next_idx = 0;
+		prb_inc_lost(&printk_rb);
+		return 0;
 	}
 
 	/* fill message */
-	msg = (struct printk_log *)(log_buf + log_next_idx);
+	msg = (struct printk_log *)rbuf;
 	memcpy(log_text(msg), text, text_len);
 	msg->text_len = text_len;
-	if (trunc_msg_len) {
-		memcpy(log_text(msg) + text_len, trunc_msg, trunc_msg_len);
-		msg->text_len += trunc_msg_len;
-	}
 	memcpy(log_dict(msg), dict, dict_len);
 	msg->dict_len = dict_len;
 	msg->facility = facility;
 	msg->level = level & 7;
 	msg->flags = flags & 0x1f;
-	if (ts_nsec > 0)
-		msg->ts_nsec = ts_nsec;
-	else
-		msg->ts_nsec = local_clock();
+	msg->ts_nsec = ts_nsec;
 #ifdef CONFIG_PRINTK_CALLER
 	msg->caller_id = caller_id;
 #endif
-	memset(log_dict(msg) + dict_len, 0, pad_len);
+	msg->cpu = cpu;
 	msg->len = size;
 
 	/* insert message */
-	log_next_idx += msg->len;
-	log_next_seq++;
+	prb_commit(&h);
 
 	return msg->text_len;
 }
@@ -727,9 +529,9 @@ static ssize_t msg_print_ext_header(char
 
 	do_div(ts_usec, 1000);
 
-	return scnprintf(buf, size, "%u,%llu,%llu,%c%s;",
+	return scnprintf(buf, size, "%u,%llu,%llu,%c%s,%hu;",
 			 (msg->facility << 3) | msg->level, seq, ts_usec,
-			 msg->flags & LOG_CONT ? 'c' : '-', caller);
+			 msg->flags & LOG_CONT ? 'c' : '-', caller, msg->cpu);
 }
 
 static ssize_t msg_print_ext_body(char *buf, size_t size,
@@ -780,13 +582,18 @@ static ssize_t msg_print_ext_body(char *
 	return p - buf;
 }
 
+#define PRINTK_SPRINT_MAX (LOG_LINE_MAX + PREFIX_MAX)
+#define PRINTK_RECORD_MAX (sizeof(struct printk_log) + \
+				CONSOLE_EXT_LOG_MAX + PRINTK_SPRINT_MAX)
+
 /* /dev/kmsg - userspace message inject/listen interface */
 struct devkmsg_user {
 	u64 seq;
-	u32 idx;
+	struct prb_iterator iter;
 	struct ratelimit_state rs;
 	struct mutex lock;
 	char buf[CONSOLE_EXT_LOG_MAX];
+	char msgbuf[PRINTK_RECORD_MAX];
 };
 
 static __printf(3, 4) __cold
@@ -869,9 +676,11 @@ static ssize_t devkmsg_read(struct file
 			    size_t count, loff_t *ppos)
 {
 	struct devkmsg_user *user = file->private_data;
+	struct prb_iterator backup_iter;
 	struct printk_log *msg;
-	size_t len;
 	ssize_t ret;
+	size_t len;
+	u64 seq;
 
 	if (!user)
 		return -EBADF;
@@ -880,52 +689,63 @@ static ssize_t devkmsg_read(struct file
 	if (ret)
 		return ret;
 
-	logbuf_lock_irq();
-	while (user->seq == log_next_seq) {
-		if (file->f_flags & O_NONBLOCK) {
-			ret = -EAGAIN;
-			logbuf_unlock_irq();
-			goto out;
-		}
+	/* make a backup copy in case there is a problem */
+	prb_iter_copy(&backup_iter, &user->iter);
 
-		logbuf_unlock_irq();
-		ret = wait_event_interruptible(log_wait,
-					       user->seq != log_next_seq);
-		if (ret)
-			goto out;
-		logbuf_lock_irq();
+	if (file->f_flags & O_NONBLOCK) {
+		ret = prb_iter_next(&user->iter, &user->msgbuf[0],
+				      sizeof(user->msgbuf), &seq);
+	} else {
+		ret = prb_iter_wait_next(&user->iter, &user->msgbuf[0],
+					   sizeof(user->msgbuf), &seq);
 	}
-
-	if (user->seq < log_first_seq) {
-		/* our last seen message is gone, return error and reset */
-		user->idx = log_first_idx;
-		user->seq = log_first_seq;
+	if (ret == 0) {
+		/* end of list */
+		ret = -EAGAIN;
+		goto out;
+	} else if (ret == -EINVAL) {
+		/* iterator invalid, return error and reset */
 		ret = -EPIPE;
-		logbuf_unlock_irq();
+		prb_iter_init(&user->iter, &printk_rb, &user->seq);
 		goto out;
+	} else if (ret < 0) {
+		/* interrupted by signal */
+		goto out;
+	}
+
+	user->seq++;
+	if (user->seq < seq) {
+		ret = -EPIPE;
+		goto restore_out;
 	}
 
-	msg = log_from_idx(user->idx);
+	msg = (struct printk_log *)&user->msgbuf[0];
 	len = msg_print_ext_header(user->buf, sizeof(user->buf),
 				   msg, user->seq);
 	len += msg_print_ext_body(user->buf + len, sizeof(user->buf) - len,
 				  log_dict(msg), msg->dict_len,
 				  log_text(msg), msg->text_len);
 
-	user->idx = log_next(user->idx);
-	user->seq++;
-	logbuf_unlock_irq();
-
 	if (len > count) {
 		ret = -EINVAL;
-		goto out;
+		goto restore_out;
 	}
 
 	if (copy_to_user(buf, user->buf, len)) {
 		ret = -EFAULT;
-		goto out;
+		goto restore_out;
 	}
+
 	ret = len;
+	goto out;
+restore_out:
+	/*
+	 * There was an error, but this message should not be
+	 * lost because of it. Restore the backup and setup
+	 * seq so that it will work with the next read.
+	 */
+	prb_iter_copy(&user->iter, &backup_iter);
+	user->seq = seq - 1;
 out:
 	mutex_unlock(&user->lock);
 	return ret;
@@ -934,19 +754,22 @@ out:
 static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
 {
 	struct devkmsg_user *user = file->private_data;
-	loff_t ret = 0;
+	loff_t ret;
+	u64 seq;
 
 	if (!user)
 		return -EBADF;
 	if (offset)
 		return -ESPIPE;
 
-	logbuf_lock_irq();
+	ret = mutex_lock_interruptible(&user->lock);
+	if (ret)
+		return ret;
+
 	switch (whence) {
 	case SEEK_SET:
 		/* the first record */
-		user->idx = log_first_idx;
-		user->seq = log_first_seq;
+		prb_iter_init(&user->iter, &printk_rb, &user->seq);
 		break;
 	case SEEK_DATA:
 		/*
@@ -954,40 +777,87 @@ static loff_t devkmsg_llseek(struct file
 		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
 		 * changes no global state, and does not clear anything.
 		 */
-		user->idx = clear_idx;
-		user->seq = clear_seq;
+		for (;;) {
+			prb_iter_init(&user->iter, &printk_rb, &seq);
+			ret = prb_iter_seek(&user->iter, clear_seq);
+			if (ret > 0) {
+				/* seeked to clear seq */
+				user->seq = clear_seq;
+				break;
+			} else if (ret == 0) {
+				/*
+				 * The end of the list was hit without
+				 * ever seeing the clear seq. Just
+				 * seek to the beginning of the list.
+				 */
+				prb_iter_init(&user->iter, &printk_rb,
+						&user->seq);
+				break;
+			}
+			/* iterator invalid, start over */
+
+			/* reset clear_seq if it is no longer available */
+			if (seq > clear_seq)
+				clear_seq = 0;
+		}
+		ret = 0;
 		break;
 	case SEEK_END:
 		/* after the last record */
-		user->idx = log_next_idx;
-		user->seq = log_next_seq;
+		for (;;) {
+			ret = prb_iter_next(&user->iter, NULL, 0, &user->seq);
+			if (ret == 0)
+				break;
+			else if (ret > 0)
+				continue;
+			/* iterator invalid, start over */
+			prb_iter_init(&user->iter, &printk_rb, &user->seq);
+		}
+		ret = 0;
 		break;
 	default:
 		ret = -EINVAL;
 	}
-	logbuf_unlock_irq();
+
+	mutex_unlock(&user->lock);
 	return ret;
 }
 
+struct wait_queue_head *printk_wait_queue(void)
+{
+	/* FIXME: using prb internals! */
+	return printk_rb.wq;
+}
+
 static __poll_t devkmsg_poll(struct file *file, poll_table *wait)
 {
 	struct devkmsg_user *user = file->private_data;
+	struct prb_iterator iter;
 	__poll_t ret = 0;
+	int rbret;
+	u64 seq;
 
 	if (!user)
 		return EPOLLERR|EPOLLNVAL;
 
-	poll_wait(file, &log_wait, wait);
+	poll_wait(file, printk_wait_queue(), wait);
 
-	logbuf_lock_irq();
-	if (user->seq < log_next_seq) {
-		/* return error when data has vanished underneath us */
-		if (user->seq < log_first_seq)
-			ret = EPOLLIN|EPOLLRDNORM|EPOLLERR|EPOLLPRI;
-		else
-			ret = EPOLLIN|EPOLLRDNORM;
-	}
-	logbuf_unlock_irq();
+	mutex_lock(&user->lock);
+
+	/* use copy so no actual iteration takes place */
+	prb_iter_copy(&iter, &user->iter);
+
+	rbret = prb_iter_next(&iter, &user->msgbuf[0],
+				sizeof(user->msgbuf), &seq);
+	if (rbret == 0)
+		goto out;
+
+	ret = EPOLLIN|EPOLLRDNORM;
+
+	if (rbret < 0 || (seq - user->seq) != 1)
+		ret |= EPOLLERR|EPOLLPRI;
+out:
+	mutex_unlock(&user->lock);
 
 	return ret;
 }
@@ -1017,10 +887,7 @@ static int devkmsg_open(struct inode *in
 
 	mutex_init(&user->lock);
 
-	logbuf_lock_irq();
-	user->idx = log_first_idx;
-	user->seq = log_first_seq;
-	logbuf_unlock_irq();
+	prb_iter_init(&user->iter, &printk_rb, &user->seq);
 
 	file->private_data = user;
 	return 0;
@@ -1060,11 +927,6 @@ const struct file_operations kmsg_fops =
  */
 void log_buf_vmcoreinfo_setup(void)
 {
-	VMCOREINFO_SYMBOL(log_buf);
-	VMCOREINFO_SYMBOL(log_buf_len);
-	VMCOREINFO_SYMBOL(log_first_idx);
-	VMCOREINFO_SYMBOL(clear_idx);
-	VMCOREINFO_SYMBOL(log_next_idx);
 	/*
 	 * Export struct printk_log size and field offsets. User space tools can
 	 * parse it and detect any changes to structure down the line.
@@ -1080,6 +942,8 @@ void log_buf_vmcoreinfo_setup(void)
 }
 #endif
 
+/* FIXME: no support for buffer resizing */
+#if 0
 /* requested log_buf_len from kernel cmdline */
 static unsigned long __initdata new_log_buf_len;
 
@@ -1145,9 +1009,12 @@ static void __init log_buf_add_cpu(void)
 #else /* !CONFIG_SMP */
 static inline void log_buf_add_cpu(void) {}
 #endif /* CONFIG_SMP */
+#endif /* 0 */
 
 void __init setup_log_buf(int early)
 {
+/* FIXME: no support for buffer resizing */
+#if 0
 	unsigned long flags;
 	char *new_log_buf;
 	unsigned int free;
@@ -1179,6 +1046,7 @@ void __init setup_log_buf(int early)
 	pr_info("log_buf_len: %u bytes\n", log_buf_len);
 	pr_info("early log buf free: %u(%u%%)\n",
 		free, (free * 100) / __LOG_BUF_LEN);
+#endif
 }
 
 static bool __read_mostly ignore_loglevel;
@@ -1259,6 +1127,11 @@ static inline void boot_delay_msec(int l
 static bool printk_time = IS_ENABLED(CONFIG_PRINTK_TIME);
 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
 
+static size_t print_cpu(u16 cpu, char *buf)
+{
+	return sprintf(buf, "%03hu: ", cpu);
+}
+
 static size_t print_syslog(unsigned int level, char *buf)
 {
 	return sprintf(buf, "<%u>", level);
@@ -1302,6 +1175,7 @@ static size_t print_prefix(const struct
 		buf[len++] = ' ';
 		buf[len] = '\0';
 	}
+	len += print_cpu(msg->cpu, buf + len);
 
 	return len;
 }
@@ -1347,30 +1221,42 @@ static size_t msg_print_text(const struc
 	return len;
 }
 
-static int syslog_print(char __user *buf, int size)
+static int syslog_print(char __user *buf, int size, char *text,
+			char *msgbuf, int *locked)
 {
-	char *text;
+	struct prb_iterator iter;
 	struct printk_log *msg;
 	int len = 0;
-
-	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
-	if (!text)
-		return -ENOMEM;
+	u64 seq;
+	int ret;
 
 	while (size > 0) {
 		size_t n;
 		size_t skip;
 
-		logbuf_lock_irq();
-		if (syslog_seq < log_first_seq) {
-			/* messages are gone, move to first one */
-			syslog_seq = log_first_seq;
-			syslog_idx = log_first_idx;
-			syslog_partial = 0;
+		for (;;) {
+			prb_iter_copy(&iter, &syslog_iter);
+			ret = prb_iter_next(&iter, msgbuf,
+					    PRINTK_RECORD_MAX, &seq);
+			if (ret < 0) {
+				/* messages are gone, move to first one */
+				prb_iter_init(&syslog_iter, &printk_rb,
+					      &syslog_seq);
+				syslog_partial = 0;
+				continue;
+			}
+			break;
 		}
-		if (syslog_seq == log_next_seq) {
-			logbuf_unlock_irq();
+		if (ret == 0)
 			break;
+
+		/*
+		 * If messages have been missed, the partial tracker
+		 * is no longer valid and must be reset.
+		 */
+		if (syslog_seq > 0 && seq - 1 != syslog_seq) {
+			syslog_seq = seq - 1;
+			syslog_partial = 0;
 		}
 
 		/*
@@ -1380,131 +1266,215 @@ static int syslog_print(char __user *buf
 		if (!syslog_partial)
 			syslog_time = printk_time;
 
+		msg = (struct printk_log *)msgbuf;
+
 		skip = syslog_partial;
-		msg = log_from_idx(syslog_idx);
 		n = msg_print_text(msg, true, syslog_time, text,
-				   LOG_LINE_MAX + PREFIX_MAX);
+				   PRINTK_SPRINT_MAX);
 		if (n - syslog_partial <= size) {
 			/* message fits into buffer, move forward */
-			syslog_idx = log_next(syslog_idx);
-			syslog_seq++;
+			prb_iter_next(&syslog_iter, NULL, 0, &syslog_seq);
 			n -= syslog_partial;
 			syslog_partial = 0;
-		} else if (!len){
+		} else if (!len) {
 			/* partial read(), remember position */
 			n = size;
 			syslog_partial += n;
 		} else
 			n = 0;
-		logbuf_unlock_irq();
 
 		if (!n)
 			break;
 
+		mutex_unlock(&syslog_lock);
 		if (copy_to_user(buf, text + skip, n)) {
 			if (!len)
 				len = -EFAULT;
+			*locked = 0;
 			break;
 		}
+		ret = mutex_lock_interruptible(&syslog_lock);
 
 		len += n;
 		size -= n;
 		buf += n;
+
+		if (ret) {
+			if (!len)
+				len = ret;
+			*locked = 0;
+			break;
+		}
 	}
 
-	kfree(text);
 	return len;
 }
 
-static int syslog_print_all(char __user *buf, int size, bool clear)
+static int count_remaining(struct prb_iterator *iter, u64 until_seq,
+			   char *msgbuf, int size, bool records, bool time)
 {
-	char *text;
+	struct prb_iterator local_iter;
+	struct printk_log *msg;
 	int len = 0;
-	u64 next_seq;
 	u64 seq;
-	u32 idx;
+	int ret;
+
+	prb_iter_copy(&local_iter, iter);
+	for (;;) {
+		ret = prb_iter_next(&local_iter, msgbuf, size, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/* the iter is invalid, restart from head */
+			prb_iter_init(&local_iter, &printk_rb, NULL);
+			len = 0;
+			continue;
+		}
+
+		if (until_seq && seq >= until_seq)
+			break;
+
+		if (records) {
+			len++;
+		} else {
+			msg = (struct printk_log *)msgbuf;
+			len += msg_print_text(msg, true, time, NULL, 0);
+		}
+	}
+
+	return len;
+}
+
+static void syslog_clear(void)
+{
+	struct prb_iterator iter;
+	int ret;
+
+	prb_iter_init(&iter, &printk_rb, &clear_seq);
+	for (;;) {
+		ret = prb_iter_next(&iter, NULL, 0, &clear_seq);
+		if (ret == 0)
+			break;
+		else if (ret < 0)
+			prb_iter_init(&iter, &printk_rb, &clear_seq);
+	}
+}
+
+static int syslog_print_all(char __user *buf, int size, bool clear)
+{
+	struct prb_iterator iter;
+	struct printk_log *msg;
+	char *msgbuf = NULL;
+	char *text = NULL;
+	int textlen;
+	u64 seq = 0;
+	int len = 0;
 	bool time;
+	int ret;
 
-	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
+	text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
 	if (!text)
 		return -ENOMEM;
+	msgbuf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+	if (!msgbuf) {
+		kfree(text);
+		return -ENOMEM;
+	}
 
 	time = printk_time;
-	logbuf_lock_irq();
+
 	/*
-	 * Find first record that fits, including all following records,
-	 * into the user-provided buffer for this dump.
+	 * Setup iter to last event before clear. Clear may
+	 * be lost, but keep going with a best effort.
 	 */
-	seq = clear_seq;
-	idx = clear_idx;
-	while (seq < log_next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-
-		len += msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
-	}
-
-	/* move first record forward until length fits into the buffer */
-	seq = clear_seq;
-	idx = clear_idx;
-	while (len > size && seq < log_next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
+	prb_iter_init(&iter, &printk_rb, NULL);
+	prb_iter_seek(&iter, clear_seq);
+
+	/* count the total bytes after clear */
+	len = count_remaining(&iter, 0, msgbuf, PRINTK_RECORD_MAX,
+			      false, time);
+
+	/* move iter forward until length fits into the buffer */
+	while (len > size) {
+		ret = prb_iter_next(&iter, msgbuf,
+				    PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/*
+			 * The iter is now invalid so clear will
+			 * also be invalid. Restart from the head.
+			 */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			len = count_remaining(&iter, 0, msgbuf,
+					      PRINTK_RECORD_MAX, false, time);
+			continue;
+		}
 
+		msg = (struct printk_log *)msgbuf;
 		len -= msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
-	}
 
-	/* last message fitting into this dump */
-	next_seq = log_next_seq;
+		if (clear)
+			clear_seq = seq;
+	}
 
+	/* copy messages to buffer */
 	len = 0;
-	while (len >= 0 && seq < next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
-		int textlen = msg_print_text(msg, true, time, text,
-					     LOG_LINE_MAX + PREFIX_MAX);
+	while (len >= 0 && len < size) {
+		if (clear)
+			clear_seq = seq;
+
+		ret = prb_iter_next(&iter, msgbuf,
+				    PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/*
+			 * The iter is now invalid. Make a best
+			 * effort to grab the rest of the log
+			 * from the new head.
+			 */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
+
+		msg = (struct printk_log *)msgbuf;
+		textlen = msg_print_text(msg, true, time, text,
+					 PRINTK_SPRINT_MAX);
+		if (textlen < 0) {
+			len = textlen;
+			break;
+		}
 
-		idx = log_next(idx);
-		seq++;
+		if (len + textlen > size)
+			break;
 
-		logbuf_unlock_irq();
 		if (copy_to_user(buf + len, text, textlen))
 			len = -EFAULT;
 		else
 			len += textlen;
-		logbuf_lock_irq();
-
-		if (seq < log_first_seq) {
-			/* messages are gone, move to next one */
-			seq = log_first_seq;
-			idx = log_first_idx;
-		}
 	}
 
-	if (clear) {
-		clear_seq = log_next_seq;
-		clear_idx = log_next_idx;
-	}
-	logbuf_unlock_irq();
+	if (clear && !seq)
+		syslog_clear();
 
-	kfree(text);
+	if (text)
+		kfree(text);
+	if (msgbuf)
+		kfree(msgbuf);
 	return len;
 }
 
-static void syslog_clear(void)
-{
-	logbuf_lock_irq();
-	clear_seq = log_next_seq;
-	clear_idx = log_next_idx;
-	logbuf_unlock_irq();
-}
-
 int do_syslog(int type, char __user *buf, int len, int source)
 {
 	bool clear = false;
 	static int saved_console_loglevel = LOGLEVEL_DEFAULT;
+	struct prb_iterator iter;
+	char *msgbuf = NULL;
+	char *text = NULL;
+	int locked;
 	int error;
+	int ret;
 
 	error = check_syslog_permissions(type, source);
 	if (error)
@@ -1522,11 +1492,49 @@ int do_syslog(int type, char __user *buf
 			return 0;
 		if (!access_ok(buf, len))
 			return -EFAULT;
-		error = wait_event_interruptible(log_wait,
-						 syslog_seq != log_next_seq);
+
+		text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+		msgbuf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+		if (!text || !msgbuf) {
+			error = -ENOMEM;
+			goto out;
+		}
+
+		error = mutex_lock_interruptible(&syslog_lock);
 		if (error)
-			return error;
-		error = syslog_print(buf, len);
+			goto out;
+
+		/*
+		 * Wait until a first message is available. Use a copy
+		 * because no iteration should occur for syslog now.
+		 */
+		for (;;) {
+			prb_iter_copy(&iter, &syslog_iter);
+
+			mutex_unlock(&syslog_lock);
+			ret = prb_iter_wait_next(&iter, NULL, 0, NULL);
+			if (ret == -ERESTARTSYS) {
+				error = ret;
+				goto out;
+			}
+			error = mutex_lock_interruptible(&syslog_lock);
+			if (error)
+				goto out;
+
+			if (ret == -EINVAL) {
+				prb_iter_init(&syslog_iter, &printk_rb,
+					      &syslog_seq);
+				syslog_partial = 0;
+				continue;
+			}
+			break;
+		}
+
+		/* print as much as will fit in the user buffer */
+		locked = 1;
+		error = syslog_print(buf, len, text, msgbuf, &locked);
+		if (locked)
+			mutex_unlock(&syslog_lock);
 		break;
 	/* Read/clear last kernel messages */
 	case SYSLOG_ACTION_READ_CLEAR:
@@ -1571,47 +1579,45 @@ int do_syslog(int type, char __user *buf
 		break;
 	/* Number of chars in the log buffer */
 	case SYSLOG_ACTION_SIZE_UNREAD:
-		logbuf_lock_irq();
-		if (syslog_seq < log_first_seq) {
-			/* messages are gone, move to first one */
-			syslog_seq = log_first_seq;
-			syslog_idx = log_first_idx;
-			syslog_partial = 0;
-		}
+		msgbuf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+		if (!msgbuf)
+			return -ENOMEM;
+
+		error = mutex_lock_interruptible(&syslog_lock);
+		if (error)
+			goto out;
+
 		if (source == SYSLOG_FROM_PROC) {
 			/*
 			 * Short-cut for poll(/"proc/kmsg") which simply checks
 			 * for pending data, not the size; return the count of
 			 * records, not the length.
 			 */
-			error = log_next_seq - syslog_seq;
+			error = count_remaining(&syslog_iter, 0, msgbuf,
+						PRINTK_RECORD_MAX, true,
+						printk_time);
 		} else {
-			u64 seq = syslog_seq;
-			u32 idx = syslog_idx;
-			bool time = syslog_partial ? syslog_time : printk_time;
-
-			while (seq < log_next_seq) {
-				struct printk_log *msg = log_from_idx(idx);
-
-				error += msg_print_text(msg, true, time, NULL,
-							0);
-				time = printk_time;
-				idx = log_next(idx);
-				seq++;
-			}
+			error = count_remaining(&syslog_iter, 0, msgbuf,
+						PRINTK_RECORD_MAX, false,
+						printk_time);
 			error -= syslog_partial;
 		}
-		logbuf_unlock_irq();
+
+		mutex_unlock(&syslog_lock);
 		break;
 	/* Size of the log buffer */
 	case SYSLOG_ACTION_SIZE_BUFFER:
-		error = log_buf_len;
+		error = prb_buffer_size(&printk_rb);
 		break;
 	default:
 		error = -EINVAL;
 		break;
 	}
-
+out:
+	if (msgbuf)
+		kfree(msgbuf);
+	if (text)
+		kfree(text);
 	return error;
 }
 
@@ -1620,144 +1626,128 @@ SYSCALL_DEFINE3(syslog, int, type, char
 	return do_syslog(type, buf, len, SYSLOG_FROM_READER);
 }
 
-/*
- * Special console_lock variants that help to reduce the risk of soft-lockups.
- * They allow to pass console_lock to another printk() call using a busy wait.
- */
+int printk_delay_msec __read_mostly;
 
-#ifdef CONFIG_LOCKDEP
-static struct lockdep_map console_owner_dep_map = {
-	.name = "console_owner"
-};
-#endif
+static inline void printk_delay(int level)
+{
+	boot_delay_msec(level);
+	if (unlikely(printk_delay_msec)) {
+		int m = printk_delay_msec;
 
-static DEFINE_RAW_SPINLOCK(console_owner_lock);
-static struct task_struct *console_owner;
-static bool console_waiter;
+		while (m--) {
+			mdelay(1);
+			touch_nmi_watchdog();
+		}
+	}
+}
 
-/**
- * console_lock_spinning_enable - mark beginning of code where another
- *	thread might safely busy wait
- *
- * This basically converts console_lock into a spinlock. This marks
- * the section where the console_lock owner can not sleep, because
- * there may be a waiter spinning (like a spinlock). Also it must be
- * ready to hand over the lock at the end of the section.
- */
-static void console_lock_spinning_enable(void)
-{
-	raw_spin_lock(&console_owner_lock);
-	console_owner = current;
-	raw_spin_unlock(&console_owner_lock);
+static void print_console_dropped(struct console *con, u64 count)
+{
+	char text[64];
+	int len;
 
-	/* The waiter may spin on us after setting console_owner */
-	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
+	len = sprintf(text, "** %llu printk message%s dropped **\n",
+		      count, count > 1 ? "s" : "");
+	con->write(con, text, len);
 }
 
-/**
- * console_lock_spinning_disable_and_check - mark end of code where another
- *	thread was able to busy wait and check if there is a waiter
- *
- * This is called at the end of the section where spinning is allowed.
- * It has two functions. First, it is a signal that it is no longer
- * safe to start busy waiting for the lock. Second, it checks if
- * there is a busy waiter and passes the lock rights to her.
- *
- * Important: Callers lose the lock if there was a busy waiter.
- *	They must not touch items synchronized by console_lock
- *	in this case.
- *
- * Return: 1 if the lock rights were passed, 0 otherwise.
- */
-static int console_lock_spinning_disable_and_check(void)
+static void format_text(struct printk_log *msg, u64 seq,
+			char *ext_text, size_t *ext_len,
+			char *text, size_t *len, bool time)
 {
-	int waiter;
-
-	raw_spin_lock(&console_owner_lock);
-	waiter = READ_ONCE(console_waiter);
-	console_owner = NULL;
-	raw_spin_unlock(&console_owner_lock);
+	if (suppress_message_printing(msg->level)) {
+		/*
+		 * Skip record that has level above the console
+		 * loglevel and update each console's local seq.
+		 */
+		*len = 0;
+		*ext_len = 0;
+		return;
+	}
 
-	if (!waiter) {
-		spin_release(&console_owner_dep_map, 1, _THIS_IP_);
-		return 0;
+	*len = msg_print_text(msg, console_msg_format & MSG_FORMAT_SYSLOG,
+			      time, text, PRINTK_SPRINT_MAX);
+	if (nr_ext_console_drivers) {
+		*ext_len = msg_print_ext_header(ext_text, CONSOLE_EXT_LOG_MAX,
+						msg, seq);
+		*ext_len += msg_print_ext_body(ext_text + *ext_len,
+					       CONSOLE_EXT_LOG_MAX - *ext_len,
+					       log_dict(msg), msg->dict_len,
+					       log_text(msg), msg->text_len);
+	} else {
+		*ext_len = 0;
 	}
+}
 
-	/* The waiter is now free to continue */
-	WRITE_ONCE(console_waiter, false);
+static void printk_write_history(struct console *con, u64 master_seq)
+{
+	struct prb_iterator iter;
+	bool time = printk_time;
+	static char *ext_text;
+	static char *text;
+	static char *buf;
+	u64 seq;
 
-	spin_release(&console_owner_dep_map, 1, _THIS_IP_);
+	ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL);
+	text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+	buf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+	if (!ext_text || !text || !buf)
+		return;
 
-	/*
-	 * Hand off console_lock to waiter. The waiter will perform
-	 * the up(). After this, the waiter is the console_lock owner.
-	 */
-	mutex_release(&console_lock_dep_map, 1, _THIS_IP_);
-	return 1;
-}
+	if (!(con->flags & CON_ENABLED))
+		goto out;
 
-/**
- * console_trylock_spinning - try to get console_lock by busy waiting
- *
- * This allows to busy wait for the console_lock when the current
- * owner is running in specially marked sections. It means that
- * the current owner is running and cannot reschedule until it
- * is ready to lose the lock.
- *
- * Return: 1 if we got the lock, 0 othrewise
- */
-static int console_trylock_spinning(void)
-{
-	struct task_struct *owner = NULL;
-	bool waiter;
-	bool spin = false;
-	unsigned long flags;
+	if (!con->write)
+		goto out;
 
-	if (console_trylock())
-		return 1;
+	if (!cpu_online(raw_smp_processor_id()) &&
+	    !(con->flags & CON_ANYTIME))
+		goto out;
 
-	printk_safe_enter_irqsave(flags);
+	prb_iter_init(&iter, &printk_rb, NULL);
 
-	raw_spin_lock(&console_owner_lock);
-	owner = READ_ONCE(console_owner);
-	waiter = READ_ONCE(console_waiter);
-	if (!waiter && owner && owner != current) {
-		WRITE_ONCE(console_waiter, true);
-		spin = true;
-	}
-	raw_spin_unlock(&console_owner_lock);
-
-	/*
-	 * If there is an active printk() writing to the
-	 * consoles, instead of having it write our data too,
-	 * see if we can offload that load from the active
-	 * printer, and do some printing ourselves.
-	 * Go into a spin only if there isn't already a waiter
-	 * spinning, and there is an active printer, and
-	 * that active printer isn't us (recursive printk?).
-	 */
-	if (!spin) {
-		printk_safe_exit_irqrestore(flags);
-		return 0;
-	}
+	for (;;) {
+		struct printk_log *msg;
+		size_t ext_len;
+		size_t len;
+		int ret;
 
-	/* We spin waiting for the owner to release us */
-	spin_acquire(&console_owner_dep_map, 0, 0, _THIS_IP_);
-	/* Owner will clear console_waiter on hand off */
-	while (READ_ONCE(console_waiter))
-		cpu_relax();
-	spin_release(&console_owner_dep_map, 1, _THIS_IP_);
+		ret = prb_iter_next(&iter, buf, PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
 
-	printk_safe_exit_irqrestore(flags);
-	/*
-	 * The owner passed the console lock to us.
-	 * Since we did not spin on console lock, annotate
-	 * this as a trylock. Otherwise lockdep will
-	 * complain.
-	 */
-	mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_);
+		if (seq > master_seq)
+			break;
 
-	return 1;
+		con->printk_seq++;
+		if (con->printk_seq < seq) {
+			print_console_dropped(con, seq - con->printk_seq);
+			con->printk_seq = seq;
+		}
+
+		msg = (struct printk_log *)buf;
+		format_text(msg, master_seq, ext_text, &ext_len, text,
+			    &len, time);
+
+		if (len == 0 && ext_len == 0)
+			continue;
+
+		if (con->flags & CON_EXTENDED)
+			con->write(con, ext_text, ext_len);
+		else
+			con->write(con, text, len);
+
+		printk_delay(msg->level);
+	}
+out:
+	con->wrote_history = 1;
+	kfree(ext_text);
+	kfree(text);
+	kfree(buf);
 }
 
 /*
@@ -1765,8 +1755,9 @@ static int console_trylock_spinning(void
  * log_buf[start] to log_buf[end - 1].
  * The console_lock must be held.
  */
-static void call_console_drivers(const char *ext_text, size_t ext_len,
-				 const char *text, size_t len)
+static void call_console_drivers(u64 seq, const char *ext_text, size_t ext_len,
+				 const char *text, size_t len, int level,
+				 int facility)
 {
 	struct console *con;
 
@@ -1776,15 +1767,40 @@ static void call_console_drivers(const c
 		return;
 
 	for_each_console(con) {
-		if (exclusive_console && con != exclusive_console)
-			continue;
 		if (!(con->flags & CON_ENABLED))
 			continue;
+		if (!con->wrote_history) {
+			if (con->flags & CON_PRINTBUFFER) {
+				printk_write_history(con, seq);
+				continue;
+			}
+			con->wrote_history = 1;
+			con->printk_seq = seq - 1;
+		}
+		if (con->flags & CON_BOOT && facility == 0) {
+			/* skip boot messages, already printed */
+			if (con->printk_seq < seq)
+				con->printk_seq = seq;
+			continue;
+		}
 		if (!con->write)
 			continue;
-		if (!cpu_online(smp_processor_id()) &&
+		if (!cpu_online(raw_smp_processor_id()) &&
 		    !(con->flags & CON_ANYTIME))
 			continue;
+		if (con->printk_seq >= seq)
+			continue;
+
+		con->printk_seq++;
+		if (con->printk_seq < seq) {
+			print_console_dropped(con, seq - con->printk_seq);
+			con->printk_seq = seq;
+		}
+
+		/* for supressed messages, only seq is updated */
+		if (len == 0 && ext_len == 0)
+			continue;
+
 		if (con->flags & CON_EXTENDED)
 			con->write(con, ext_text, ext_len);
 		else
@@ -1792,20 +1808,6 @@ static void call_console_drivers(const c
 	}
 }
 
-int printk_delay_msec __read_mostly;
-
-static inline void printk_delay(void)
-{
-	if (unlikely(printk_delay_msec)) {
-		int m = printk_delay_msec;
-
-		while (m--) {
-			mdelay(1);
-			touch_nmi_watchdog();
-		}
-	}
-}
-
 static inline u32 printk_caller_id(void)
 {
 	return in_task() ? task_pid_nr(current) :
@@ -1822,101 +1824,94 @@ static struct cont {
 	char buf[LOG_LINE_MAX];
 	size_t len;			/* length == 0 means unused buffer */
 	u32 caller_id;			/* printk_caller_id() of first print */
+	int cpu_owner;			/* cpu of first print */
 	u64 ts_nsec;			/* time of first print */
 	u8 level;			/* log level of first message */
 	u8 facility;			/* log facility of first message */
 	enum log_flags flags;		/* prefix, newline flags */
-} cont;
+} cont[2];
 
-static void cont_flush(void)
+static void cont_flush(int ctx)
 {
-	if (cont.len == 0)
+	struct cont *c = &cont[ctx];
+
+	if (c->len == 0)
 		return;
 
-	log_store(cont.caller_id, cont.facility, cont.level, cont.flags,
-		  cont.ts_nsec, NULL, 0, cont.buf, cont.len);
-	cont.len = 0;
+	log_store(c->caller_id, c->facility, c->level, c->flags,
+		  c->ts_nsec, c->cpu_owner, NULL, 0, c->buf, c->len);
+	c->len = 0;
 }
 
-static bool cont_add(u32 caller_id, int facility, int level,
+static void cont_add(int ctx, int cpu, u32 caller_id, int facility, int level,
 		     enum log_flags flags, const char *text, size_t len)
 {
+	struct cont *c = &cont[ctx];
+
+	if (cpu != c->cpu_owner || !(flags & LOG_CONT))
+		cont_flush(ctx);
+
 	/* If the line gets too long, split it up in separate records. */
-	if (cont.len + len > sizeof(cont.buf)) {
-		cont_flush();
-		return false;
-	}
+	while (c->len + len > sizeof(c->buf))
+		cont_flush(ctx);
 
-	if (!cont.len) {
-		cont.facility = facility;
-		cont.level = level;
-		cont.caller_id = caller_id;
-		cont.ts_nsec = local_clock();
-		cont.flags = flags;
+	if (!c->len) {
+		c->facility = facility;
+		c->level = level;
+		c->caller_id = caller_id;
+		c->ts_nsec = local_clock();
+		c->flags = flags;
+		c->cpu_owner = cpu;
 	}
 
-	memcpy(cont.buf + cont.len, text, len);
-	cont.len += len;
+	memcpy(c->buf + c->len, text, len);
+	c->len += len;
 
 	// The original flags come from the first line,
 	// but later continuations can add a newline.
 	if (flags & LOG_NEWLINE) {
-		cont.flags |= LOG_NEWLINE;
-		cont_flush();
+		c->flags |= LOG_NEWLINE;
 	}
-
-	return true;
 }
 
-static size_t log_output(int facility, int level, enum log_flags lflags, const char *dict, size_t dictlen, char *text, size_t text_len)
+/* ring buffer used as memory allocator for temporary sprint buffers */
+DECLARE_STATIC_PRINTKRB(sprint_rb,
+			ilog2(PRINTK_RECORD_MAX + sizeof(struct prb_entry) +
+			      sizeof(long)) + 2, &printk_cpulock);
+
+asmlinkage int vprintk_emit(int facility, int level,
+			    const char *dict, size_t dictlen,
+			    const char *fmt, va_list args)
 {
 	const u32 caller_id = printk_caller_id();
+	int ctx = !!in_nmi();
+	enum log_flags lflags = 0;
+	int printed_len = 0;
+	struct prb_handle h;
+	size_t text_len;
+	u64 ts_nsec;
+	char *text;
+	char *rbuf;
+	int cpu;
 
-	/*
-	 * If an earlier line was buffered, and we're a continuation
-	 * write from the same context, try to add it to the buffer.
-	 */
-	if (cont.len) {
-		if (cont.caller_id == caller_id && (lflags & LOG_CONT)) {
-			if (cont_add(caller_id, facility, level, lflags, text, text_len))
-				return text_len;
-		}
-		/* Otherwise, make sure it's flushed */
-		cont_flush();
-	}
-
-	/* Skip empty continuation lines that couldn't be added - they just flush */
-	if (!text_len && (lflags & LOG_CONT))
-		return 0;
+	ts_nsec = local_clock();
 
-	/* If it doesn't end in a newline, try to buffer the current line */
-	if (!(lflags & LOG_NEWLINE)) {
-		if (cont_add(caller_id, facility, level, lflags, text, text_len))
-			return text_len;
+	rbuf = prb_reserve(&h, &sprint_rb, PRINTK_SPRINT_MAX);
+	if (!rbuf) {
+		prb_inc_lost(&printk_rb);
+		return printed_len;
 	}
 
-	/* Store it in the record log */
-	return log_store(caller_id, facility, level, lflags, 0,
-			 dict, dictlen, text, text_len);
-}
-
-/* Must be called under logbuf_lock. */
-int vprintk_store(int facility, int level,
-		  const char *dict, size_t dictlen,
-		  const char *fmt, va_list args)
-{
-	static char textbuf[LOG_LINE_MAX];
-	char *text = textbuf;
-	size_t text_len;
-	enum log_flags lflags = 0;
+	cpu = raw_smp_processor_id();
 
 	/*
-	 * The printf needs to come first; we need the syslog
-	 * prefix which might be passed-in as a parameter.
+	 * If this turns out to be an emergency message, there
+	 * may need to be a prefix added. Leave room for it.
 	 */
-	text_len = vscnprintf(text, sizeof(textbuf), fmt, args);
+	text = rbuf + PREFIX_MAX;
+	text_len = vscnprintf(text, PRINTK_SPRINT_MAX - PREFIX_MAX, fmt, args);
 
-	/* mark and strip a trailing newline */
+	/* strip and flag a trailing newline */
 	if (text_len && text[text_len-1] == '\n') {
 		text_len--;
 		lflags |= LOG_NEWLINE;
@@ -1947,62 +1942,37 @@ int vprintk_store(int facility, int leve
 	if (dict)
 		lflags |= LOG_NEWLINE;
 
-	return log_output(facility, level, lflags,
-			  dict, dictlen, text, text_len);
-}
-
-asmlinkage int vprintk_emit(int facility, int level,
-			    const char *dict, size_t dictlen,
-			    const char *fmt, va_list args)
-{
-	int printed_len;
-	bool in_sched = false, pending_output;
-	unsigned long flags;
-	u64 curr_log_seq;
-
-	/* Suppress unimportant messages after panic happens */
-	if (unlikely(suppress_printk))
-		return 0;
-
-	if (level == LOGLEVEL_SCHED) {
-		level = LOGLEVEL_DEFAULT;
-		in_sched = true;
+	/*
+	 * NOTE:
+	 * - rbuf points to beginning of allocated buffer
+	 * - text points to beginning of text
+	 * - there is room before text for prefix
+	 */
+	if (facility == 0) {
+		/* only the kernel can create emergency messages */
+		printk_emergency(rbuf, level & 7, ts_nsec, cpu, text, text_len);
 	}
 
-	boot_delay_msec(level);
-	printk_delay();
-
-	/* This stops the holder of console_sem just where we want him */
-	logbuf_lock_irqsave(flags);
-	curr_log_seq = log_next_seq;
-	printed_len = vprintk_store(facility, level, dict, dictlen, fmt, args);
-	pending_output = (curr_log_seq != log_next_seq);
-	logbuf_unlock_irqrestore(flags);
-
-	/* If called from the scheduler, we can not call up(). */
-	if (!in_sched && pending_output) {
-		/*
-		 * Disable preemption to avoid being preempted while holding
-		 * console_sem which would prevent anyone from printing to
-		 * console
-		 */
-		preempt_disable();
-		/*
-		 * Try to acquire and then immediately release the console
-		 * semaphore.  The release will print out buffers and wake up
-		 * /dev/kmsg and syslog() users.
-		 */
-		if (console_trylock_spinning())
-			console_unlock();
-		preempt_enable();
+	if ((lflags & LOG_CONT) || !(lflags & LOG_NEWLINE)) {
+		 cont_add(ctx, cpu, caller_id, facility, level, lflags, text, text_len);
+		 printed_len = text_len;
+	} else {
+		if (cpu == cont[ctx].cpu_owner)
+			cont_flush(ctx);
+		printed_len = log_store(caller_id, facility, level, lflags, ts_nsec, cpu,
+					dict, dictlen, text, text_len);
 	}
 
-	if (pending_output)
-		wake_up_klogd();
+	prb_commit(&h);
 	return printed_len;
 }
 EXPORT_SYMBOL(vprintk_emit);
 
+static __printf(1, 0) int vprintk_func(const char *fmt, va_list args)
+{
+	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
+}
+
 asmlinkage int vprintk(const char *fmt, va_list args)
 {
 	return vprintk_func(fmt, args);
@@ -2059,39 +2029,6 @@ asmlinkage __visible int printk(const ch
 	return r;
 }
 EXPORT_SYMBOL(printk);
-
-#else /* CONFIG_PRINTK */
-
-#define LOG_LINE_MAX		0
-#define PREFIX_MAX		0
-#define printk_time		false
-
-static u64 syslog_seq;
-static u32 syslog_idx;
-static u64 console_seq;
-static u32 console_idx;
-static u64 exclusive_console_stop_seq;
-static u64 log_first_seq;
-static u32 log_first_idx;
-static u64 log_next_seq;
-static char *log_text(const struct printk_log *msg) { return NULL; }
-static char *log_dict(const struct printk_log *msg) { return NULL; }
-static struct printk_log *log_from_idx(u32 idx) { return NULL; }
-static u32 log_next(u32 idx) { return 0; }
-static ssize_t msg_print_ext_header(char *buf, size_t size,
-				    struct printk_log *msg,
-				    u64 seq) { return 0; }
-static ssize_t msg_print_ext_body(char *buf, size_t size,
-				  char *dict, size_t dict_len,
-				  char *text, size_t text_len) { return 0; }
-static void console_lock_spinning_enable(void) { }
-static int console_lock_spinning_disable_and_check(void) { return 0; }
-static void call_console_drivers(const char *ext_text, size_t ext_len,
-				 const char *text, size_t len) {}
-static size_t msg_print_text(const struct printk_log *msg, bool syslog,
-			     bool time, char *buf, size_t size) { return 0; }
-static bool suppress_message_printing(int level) { return false; }
-
 #endif /* CONFIG_PRINTK */
 
 #ifdef CONFIG_EARLY_PRINTK
@@ -2322,187 +2259,23 @@ int is_console_locked(void)
 }
 EXPORT_SYMBOL(is_console_locked);
 
-/*
- * Check if we have any console that is capable of printing while cpu is
- * booting or shutting down. Requires console_sem.
- */
-static int have_callable_console(void)
-{
-	struct console *con;
-
-	for_each_console(con)
-		if ((con->flags & CON_ENABLED) &&
-				(con->flags & CON_ANYTIME))
-			return 1;
-
-	return 0;
-}
-
-/*
- * Can we actually use the console at this time on this cpu?
- *
- * Console drivers may assume that per-cpu resources have been allocated. So
- * unless they're explicitly marked as being able to cope (CON_ANYTIME) don't
- * call them until this CPU is officially up.
- */
-static inline int can_use_console(void)
-{
-	return cpu_online(raw_smp_processor_id()) || have_callable_console();
-}
-
 /**
  * console_unlock - unlock the console system
  *
  * Releases the console_lock which the caller holds on the console system
  * and the console driver list.
  *
- * While the console_lock was held, console output may have been buffered
- * by printk().  If this is the case, console_unlock(); emits
- * the output prior to releasing the lock.
- *
- * If there is output waiting, we wake /dev/kmsg and syslog() users.
- *
  * console_unlock(); may be called from any context.
  */
 void console_unlock(void)
 {
-	static char ext_text[CONSOLE_EXT_LOG_MAX];
-	static char text[LOG_LINE_MAX + PREFIX_MAX];
-	unsigned long flags;
-	bool do_cond_resched, retry;
-
 	if (console_suspended) {
 		up_console_sem();
 		return;
 	}
 
-	/*
-	 * Console drivers are called with interrupts disabled, so
-	 * @console_may_schedule should be cleared before; however, we may
-	 * end up dumping a lot of lines, for example, if called from
-	 * console registration path, and should invoke cond_resched()
-	 * between lines if allowable.  Not doing so can cause a very long
-	 * scheduling stall on a slow console leading to RCU stall and
-	 * softlockup warnings which exacerbate the issue with more
-	 * messages practically incapacitating the system.
-	 *
-	 * console_trylock() is not able to detect the preemptive
-	 * context reliably. Therefore the value must be stored before
-	 * and cleared after the the "again" goto label.
-	 */
-	do_cond_resched = console_may_schedule;
-again:
-	console_may_schedule = 0;
-
-	/*
-	 * We released the console_sem lock, so we need to recheck if
-	 * cpu is online and (if not) is there at least one CON_ANYTIME
-	 * console.
-	 */
-	if (!can_use_console()) {
-		console_locked = 0;
-		up_console_sem();
-		return;
-	}
-
-	for (;;) {
-		struct printk_log *msg;
-		size_t ext_len = 0;
-		size_t len;
-
-		printk_safe_enter_irqsave(flags);
-		raw_spin_lock(&logbuf_lock);
-		if (console_seq < log_first_seq) {
-			len = sprintf(text,
-				      "** %llu printk messages dropped **\n",
-				      log_first_seq - console_seq);
-
-			/* messages are gone, move to first one */
-			console_seq = log_first_seq;
-			console_idx = log_first_idx;
-		} else {
-			len = 0;
-		}
-skip:
-		if (console_seq == log_next_seq)
-			break;
-
-		msg = log_from_idx(console_idx);
-		if (suppress_message_printing(msg->level)) {
-			/*
-			 * Skip record we have buffered and already printed
-			 * directly to the console when we received it, and
-			 * record that has level above the console loglevel.
-			 */
-			console_idx = log_next(console_idx);
-			console_seq++;
-			goto skip;
-		}
-
-		/* Output to all consoles once old messages replayed. */
-		if (unlikely(exclusive_console &&
-			     console_seq >= exclusive_console_stop_seq)) {
-			exclusive_console = NULL;
-		}
-
-		len += msg_print_text(msg,
-				console_msg_format & MSG_FORMAT_SYSLOG,
-				printk_time, text + len, sizeof(text) - len);
-		if (nr_ext_console_drivers) {
-			ext_len = msg_print_ext_header(ext_text,
-						sizeof(ext_text),
-						msg, console_seq);
-			ext_len += msg_print_ext_body(ext_text + ext_len,
-						sizeof(ext_text) - ext_len,
-						log_dict(msg), msg->dict_len,
-						log_text(msg), msg->text_len);
-		}
-		console_idx = log_next(console_idx);
-		console_seq++;
-		raw_spin_unlock(&logbuf_lock);
-
-		/*
-		 * While actively printing out messages, if another printk()
-		 * were to occur on another CPU, it may wait for this one to
-		 * finish. This task can not be preempted if there is a
-		 * waiter waiting to take over.
-		 */
-		console_lock_spinning_enable();
-
-		stop_critical_timings();	/* don't trace print latency */
-		call_console_drivers(ext_text, ext_len, text, len);
-		start_critical_timings();
-
-		if (console_lock_spinning_disable_and_check()) {
-			printk_safe_exit_irqrestore(flags);
-			return;
-		}
-
-		printk_safe_exit_irqrestore(flags);
-
-		if (do_cond_resched)
-			cond_resched();
-	}
-
 	console_locked = 0;
-
-	raw_spin_unlock(&logbuf_lock);
-
 	up_console_sem();
-
-	/*
-	 * Someone could have filled up the buffer again, so re-check if there's
-	 * something to flush. In case we cannot trylock the console_sem again,
-	 * there's a new owner and the console_unlock() from them will do the
-	 * flush, no worries.
-	 */
-	raw_spin_lock(&logbuf_lock);
-	retry = console_seq != log_next_seq;
-	raw_spin_unlock(&logbuf_lock);
-	printk_safe_exit_irqrestore(flags);
-
-	if (retry && console_trylock())
-		goto again;
 }
 EXPORT_SYMBOL(console_unlock);
 
@@ -2553,24 +2326,10 @@ void console_unblank(void)
 void console_flush_on_panic(enum con_flush_mode mode)
 {
 	/*
-	 * If someone else is holding the console lock, trylock will fail
-	 * and may_schedule may be set.  Ignore and proceed to unlock so
-	 * that messages are flushed out.  As this can be called from any
-	 * context and we don't want to get preempted while flushing,
-	 * ensure may_schedule is cleared.
+	 * FIXME: This is currently a NOP. Emergency messages will have been
+	 * printed, but what about if write_atomic is not available on the
+	 * console? What if the printk kthread is still alive?
 	 */
-	console_trylock();
-	console_may_schedule = 0;
-
-	if (mode == CONSOLE_REPLAY_ALL) {
-		unsigned long flags;
-
-		logbuf_lock_irqsave(flags);
-		console_seq = log_first_seq;
-		console_idx = log_first_idx;
-		logbuf_unlock_irqrestore(flags);
-	}
-	console_unlock();
 }
 
 /*
@@ -2648,7 +2407,6 @@ early_param("keep_bootcon", keep_bootcon
 void register_console(struct console *newcon)
 {
 	int i;
-	unsigned long flags;
 	struct console *bcon = NULL;
 	struct console_cmdline *c;
 	static bool has_preferred;
@@ -2764,27 +2522,6 @@ void register_console(struct console *ne
 	if (newcon->flags & CON_EXTENDED)
 		nr_ext_console_drivers++;
 
-	if (newcon->flags & CON_PRINTBUFFER) {
-		/*
-		 * console_unlock(); will print out the buffered messages
-		 * for us.
-		 */
-		logbuf_lock_irqsave(flags);
-		console_seq = syslog_seq;
-		console_idx = syslog_idx;
-		/*
-		 * We're about to replay the log buffer.  Only do this to the
-		 * just-registered console to avoid excessive message spam to
-		 * the already-registered consoles.
-		 *
-		 * Set exclusive_console with disabled interrupts to reduce
-		 * race window with eventual console_flush_on_panic() that
-		 * ignores console_lock.
-		 */
-		exclusive_console = newcon;
-		exclusive_console_stop_seq = console_seq;
-		logbuf_unlock_irqrestore(flags);
-	}
 	console_unlock();
 	console_sysfs_notify();
 
@@ -2794,6 +2531,10 @@ void register_console(struct console *ne
 	 * boot consoles, real consoles, etc - this is to ensure that end
 	 * users know there might be something in the kernel's log buffer that
 	 * went to the bootconsole (that they do not see on the real console)
+	 *
+	 * This message is also important because it will trigger the
+	 * printk kthread to begin dumping the log buffer to the newly
+	 * registered console.
 	 */
 	pr_info("%sconsole [%s%d] enabled\n",
 		(newcon->flags & CON_BOOT) ? "boot" : "" ,
@@ -2937,59 +2678,74 @@ static int __init printk_late_init(void)
 late_initcall(printk_late_init);
 
 #if defined CONFIG_PRINTK
-/*
- * Delayed printk version, for scheduler-internal messages:
- */
-#define PRINTK_PENDING_WAKEUP	0x01
-#define PRINTK_PENDING_OUTPUT	0x02
+static int printk_kthread_func(void *data)
+{
+	struct prb_iterator iter;
+	struct printk_log *msg;
+	size_t ext_len;
+	char *ext_text;
+	u64 master_seq;
+	size_t len;
+	char *text;
+	char *buf;
+	int ret;
 
-static DEFINE_PER_CPU(int, printk_pending);
+	ext_text = kmalloc(CONSOLE_EXT_LOG_MAX, GFP_KERNEL);
+	text = kmalloc(PRINTK_SPRINT_MAX, GFP_KERNEL);
+	buf = kmalloc(PRINTK_RECORD_MAX, GFP_KERNEL);
+	if (!ext_text || !text || !buf)
+		return -1;
 
-static void wake_up_klogd_work_func(struct irq_work *irq_work)
-{
-	int pending = __this_cpu_xchg(printk_pending, 0);
+	prb_iter_init(&iter, &printk_rb, NULL);
 
-	if (pending & PRINTK_PENDING_OUTPUT) {
-		/* If trylock fails, someone else is doing the printing */
-		if (console_trylock())
-			console_unlock();
+	/* the printk kthread never exits */
+	for (;;) {
+		ret = prb_iter_wait_next(&iter, buf,
+					 PRINTK_RECORD_MAX, &master_seq);
+		if (ret == -ERESTARTSYS) {
+			continue;
+		} else if (ret < 0) {
+			/* iterator invalid, start over */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
+
+		msg = (struct printk_log *)buf;
+		format_text(msg, master_seq, ext_text, &ext_len, text,
+			    &len, printk_time);
+
+		console_lock();
+		call_console_drivers(master_seq, ext_text, ext_len, text, len,
+				     msg->level, msg->facility);
+		if (len > 0 || ext_len > 0)
+			printk_delay(msg->level);
+		console_unlock();
 	}
 
-	if (pending & PRINTK_PENDING_WAKEUP)
-		wake_up_interruptible(&log_wait);
-}
+	kfree(ext_text);
+	kfree(text);
+	kfree(buf);
 
-static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
-	.func = wake_up_klogd_work_func,
-	.flags = IRQ_WORK_LAZY,
-};
+	return 0;
+}
 
-void wake_up_klogd(void)
+static int __init init_printk_kthread(void)
 {
-	preempt_disable();
-	if (waitqueue_active(&log_wait)) {
-		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
-		irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
+	struct task_struct *thread;
+
+	thread = kthread_run(printk_kthread_func, NULL, "printk");
+	if (IS_ERR(thread)) {
+		pr_err("printk: unable to create printing thread\n");
+		return PTR_ERR(thread);
 	}
-	preempt_enable();
-}
 
-void defer_console_output(void)
-{
-	preempt_disable();
-	__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
-	irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
-	preempt_enable();
+	return 0;
 }
+late_initcall(init_printk_kthread);
 
-int vprintk_deferred(const char *fmt, va_list args)
+static int vprintk_deferred(const char *fmt, va_list args)
 {
-	int r;
-
-	r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args);
-	defer_console_output();
-
-	return r;
+	return vprintk_emit(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
 }
 
 int printk_deferred(const char *fmt, ...)
@@ -3111,8 +2867,8 @@ module_param_named(always_kmsg_dump, alw
  */
 void kmsg_dump(enum kmsg_dump_reason reason)
 {
+	struct kmsg_dumper dumper_local;
 	struct kmsg_dumper *dumper;
-	unsigned long flags;
 
 	if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
 		return;
@@ -3122,21 +2878,18 @@ void kmsg_dump(enum kmsg_dump_reason rea
 		if (dumper->max_reason && reason > dumper->max_reason)
 			continue;
 
-		/* initialize iterator with data about the stored records */
-		dumper->active = true;
+		/*
+		 * use a local copy to avoid modifying the
+		 * iterator used by any other cpus/contexts
+		 */
+		memcpy(&dumper_local, dumper, sizeof(dumper_local));
 
-		logbuf_lock_irqsave(flags);
-		dumper->cur_seq = clear_seq;
-		dumper->cur_idx = clear_idx;
-		dumper->next_seq = log_next_seq;
-		dumper->next_idx = log_next_idx;
-		logbuf_unlock_irqrestore(flags);
+		/* initialize iterator with data about the stored records */
+		dumper_local.active = true;
+		kmsg_dump_rewind(&dumper_local);
 
 		/* invoke dumper which will iterate over records */
-		dumper->dump(dumper, reason);
-
-		/* reset iterator */
-		dumper->active = false;
+		dumper_local.dump(&dumper_local, reason);
 	}
 	rcu_read_unlock();
 }
@@ -3163,33 +2916,67 @@ void kmsg_dump(enum kmsg_dump_reason rea
 bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
 			       char *line, size_t size, size_t *len)
 {
+	struct prb_iterator iter;
 	struct printk_log *msg;
-	size_t l = 0;
-	bool ret = false;
+	struct prb_handle h;
+	bool cont = false;
+	char *msgbuf;
+	char *rbuf;
+	size_t l;
+	u64 seq;
+	int ret;
 
 	if (!dumper->active)
-		goto out;
+		return cont;
+
+	rbuf = prb_reserve(&h, &sprint_rb, PRINTK_RECORD_MAX);
+	if (!rbuf)
+		return cont;
+	msgbuf = rbuf;
+retry:
+	for (;;) {
+		prb_iter_init(&iter, &printk_rb, &seq);
 
-	if (dumper->cur_seq < log_first_seq) {
-		/* messages are gone, move to first available one */
-		dumper->cur_seq = log_first_seq;
-		dumper->cur_idx = log_first_idx;
+		if (dumper->line_seq == seq) {
+			/* already where we want to be */
+			break;
+		} else if (dumper->line_seq < seq) {
+			/* messages are gone, move to first available one */
+			dumper->line_seq = seq;
+			break;
+		}
+
+		ret = prb_iter_seek(&iter, dumper->line_seq);
+		if (ret > 0) {
+			/* seeked to line_seq */
+			break;
+		} else if (ret == 0) {
+			/*
+			 * The end of the list was hit without ever seeing
+			 * line_seq. Reset it to the beginning of the list.
+			 */
+			prb_iter_init(&iter, &printk_rb, &dumper->line_seq);
+			break;
+		}
+		/* iterator invalid, start over */
 	}
 
-	/* last entry */
-	if (dumper->cur_seq >= log_next_seq)
+	ret = prb_iter_next(&iter, msgbuf, PRINTK_RECORD_MAX,
+			    &dumper->line_seq);
+	if (ret == 0)
 		goto out;
+	else if (ret < 0)
+		goto retry;
 
-	msg = log_from_idx(dumper->cur_idx);
+	msg = (struct printk_log *)msgbuf;
 	l = msg_print_text(msg, syslog, printk_time, line, size);
 
-	dumper->cur_idx = log_next(dumper->cur_idx);
-	dumper->cur_seq++;
-	ret = true;
-out:
 	if (len)
 		*len = l;
-	return ret;
+	cont = true;
+out:
+	prb_commit(&h);
+	return cont;
 }
 
 /**
@@ -3212,12 +2999,9 @@ out:
 bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
 			char *line, size_t size, size_t *len)
 {
-	unsigned long flags;
 	bool ret;
 
-	logbuf_lock_irqsave(flags);
 	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
-	logbuf_unlock_irqrestore(flags);
 
 	return ret;
 }
@@ -3245,74 +3029,101 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
 bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
 			  char *buf, size_t size, size_t *len)
 {
-	unsigned long flags;
-	u64 seq;
-	u32 idx;
-	u64 next_seq;
-	u32 next_idx;
-	size_t l = 0;
-	bool ret = false;
+	struct prb_iterator iter;
 	bool time = printk_time;
+	struct printk_log *msg;
+	u64 new_end_seq = 0;
+	struct prb_handle h;
+	bool cont = false;
+	char *msgbuf;
+	u64 end_seq;
+	int textlen;
+	u64 seq = 0;
+	char *rbuf;
+	int l = 0;
+	int ret;
 
 	if (!dumper->active)
-		goto out;
+		return cont;
 
-	logbuf_lock_irqsave(flags);
-	if (dumper->cur_seq < log_first_seq) {
-		/* messages are gone, move to first available one */
-		dumper->cur_seq = log_first_seq;
-		dumper->cur_idx = log_first_idx;
-	}
+	rbuf = prb_reserve(&h, &sprint_rb, PRINTK_RECORD_MAX);
+	if (!rbuf)
+		return cont;
+	msgbuf = rbuf;
 
-	/* last entry */
-	if (dumper->cur_seq >= dumper->next_seq) {
-		logbuf_unlock_irqrestore(flags);
-		goto out;
-	}
+	prb_iter_init(&iter, &printk_rb, NULL);
 
-	/* calculate length of entire buffer */
-	seq = dumper->cur_seq;
-	idx = dumper->cur_idx;
-	while (seq < dumper->next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
+	/*
+	 * seek to the start record, which is set/modified
+	 * by kmsg_dump_get_line_nolock()
+	 */
+	ret = prb_iter_seek(&iter, dumper->line_seq);
+	if (ret <= 0)
+		prb_iter_init(&iter, &printk_rb, &seq);
 
-		l += msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
+	/* work with a local end seq to have a constant value */
+	end_seq = dumper->buffer_end_seq;
+	if (!end_seq) {
+		/* initialize end seq to "infinity" */
+		end_seq = -1;
+		dumper->buffer_end_seq = end_seq;
 	}
+retry:
+	if (seq >= end_seq)
+		goto out;
 
-	/* move first record forward until length fits into the buffer */
-	seq = dumper->cur_seq;
-	idx = dumper->cur_idx;
-	while (l >= size && seq < dumper->next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
+	/* count the total bytes after seq */
+	textlen = count_remaining(&iter, end_seq, msgbuf,
+				  PRINTK_RECORD_MAX, 0, time);
+
+	/* move iter forward until length fits into the buffer */
+	while (textlen > size) {
+		ret = prb_iter_next(&iter, msgbuf, PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0 || seq >= end_seq) {
+			prb_iter_init(&iter, &printk_rb, &seq);
+			goto retry;
+		}
 
-		l -= msg_print_text(msg, true, time, NULL, 0);
-		idx = log_next(idx);
-		seq++;
+		msg = (struct printk_log *)msgbuf;
+		textlen -= msg_print_text(msg, true, time, NULL, 0);
 	}
 
-	/* last message in next interation */
-	next_seq = seq;
-	next_idx = idx;
+	/* save end seq for the next interation */
+	new_end_seq = seq + 1;
+
+	/* copy messages to buffer */
+	while (l < size) {
+		ret = prb_iter_next(&iter, msgbuf, PRINTK_RECORD_MAX, &seq);
+		if (ret == 0) {
+			break;
+		} else if (ret < 0) {
+			/*
+			 * iterator (and thus also the start position)
+			 * invalid, start over from beginning of list
+			 */
+			prb_iter_init(&iter, &printk_rb, NULL);
+			continue;
+		}
 
-	l = 0;
-	while (seq < dumper->next_seq) {
-		struct printk_log *msg = log_from_idx(idx);
+		if (seq >= end_seq)
+			break;
 
-		l += msg_print_text(msg, syslog, time, buf + l, size - l);
-		idx = log_next(idx);
-		seq++;
+		msg = (struct printk_log *)msgbuf;
+		textlen = msg_print_text(msg, syslog, time, buf + l, size - l);
+		if (textlen > 0)
+			l += textlen;
+		cont = true;
 	}
 
-	dumper->next_seq = next_seq;
-	dumper->next_idx = next_idx;
-	ret = true;
-	logbuf_unlock_irqrestore(flags);
-out:
-	if (len)
+	if (cont && len)
 		*len = l;
-	return ret;
+out:
+	prb_commit(&h);
+	if (new_end_seq)
+		dumper->buffer_end_seq = new_end_seq;
+	return cont;
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
 
@@ -3328,10 +3139,8 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
  */
 void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
 {
-	dumper->cur_seq = clear_seq;
-	dumper->cur_idx = clear_idx;
-	dumper->next_seq = log_next_seq;
-	dumper->next_idx = log_next_idx;
+	dumper->line_seq = 0;
+	dumper->buffer_end_seq = 0;
 }
 
 /**
@@ -3344,12 +3153,89 @@ void kmsg_dump_rewind_nolock(struct kmsg
  */
 void kmsg_dump_rewind(struct kmsg_dumper *dumper)
 {
-	unsigned long flags;
-
-	logbuf_lock_irqsave(flags);
 	kmsg_dump_rewind_nolock(dumper);
-	logbuf_unlock_irqrestore(flags);
 }
 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
 
+static bool console_can_emergency(int level)
+{
+	struct console *con;
+
+	for_each_console(con) {
+		if (!(con->flags & CON_ENABLED))
+			continue;
+		if (con->write_atomic && oops_in_progress)
+			return true;
+		if (con->write && (con->flags & CON_BOOT))
+			return true;
+	}
+	return false;
+}
+
+static void call_emergency_console_drivers(int level, const char *text,
+					   size_t text_len)
+{
+	struct console *con;
+
+	for_each_console(con) {
+		if (!(con->flags & CON_ENABLED))
+			continue;
+		if (con->write_atomic && oops_in_progress) {
+			con->write_atomic(con, text, text_len);
+			continue;
+		}
+		if (con->write && (con->flags & CON_BOOT)) {
+			con->write(con, text, text_len);
+			continue;
+		}
+	}
+}
+
+static void printk_emergency(char *buffer, int level, u64 ts_nsec, u16 cpu,
+			     char *text, u16 text_len)
+{
+	struct printk_log msg;
+	size_t prefix_len;
+
+	if (!console_can_emergency(level))
+		return;
+
+	msg.level = level;
+	msg.ts_nsec = ts_nsec;
+	msg.cpu = cpu;
+	msg.facility = 0;
+
+	/* "text" must have PREFIX_MAX preceding bytes available */
+
+	prefix_len = print_prefix(&msg,
+				  console_msg_format & MSG_FORMAT_SYSLOG,
+				  printk_time, buffer);
+	/* move the prefix forward to the beginning of the message text */
+	text -= prefix_len;
+	memmove(text, buffer, prefix_len);
+	text_len += prefix_len;
+
+	text[text_len++] = '\n';
+
+	call_emergency_console_drivers(level, text, text_len);
+
+	touch_softlockup_watchdog_sync();
+	clocksource_touch_watchdog();
+	rcu_cpu_stall_reset();
+	touch_nmi_watchdog();
+
+	printk_delay(level);
+}
 #endif
+
+void console_atomic_lock(unsigned int *flags)
+{
+	prb_lock(&printk_cpulock, flags);
+}
+EXPORT_SYMBOL(console_atomic_lock);
+
+void console_atomic_unlock(unsigned int flags)
+{
+	prb_unlock(&printk_cpulock, flags);
+}
+EXPORT_SYMBOL(console_atomic_unlock);
Index: linux-5.4.5-rt3/kernel/printk/printk_safe.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/printk/printk_safe.c
+++ /dev/null
@@ -1,415 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- * printk_safe.c - Safe printk for printk-deadlock-prone contexts
- */
-
-#include <linux/preempt.h>
-#include <linux/spinlock.h>
-#include <linux/debug_locks.h>
-#include <linux/smp.h>
-#include <linux/cpumask.h>
-#include <linux/irq_work.h>
-#include <linux/printk.h>
-
-#include "internal.h"
-
-/*
- * printk() could not take logbuf_lock in NMI context. Instead,
- * it uses an alternative implementation that temporary stores
- * the strings into a per-CPU buffer. The content of the buffer
- * is later flushed into the main ring buffer via IRQ work.
- *
- * The alternative implementation is chosen transparently
- * by examinig current printk() context mask stored in @printk_context
- * per-CPU variable.
- *
- * The implementation allows to flush the strings also from another CPU.
- * There are situations when we want to make sure that all buffers
- * were handled or when IRQs are blocked.
- */
-static int printk_safe_irq_ready __read_mostly;
-
-#define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) -	\
-				sizeof(atomic_t) -			\
-				sizeof(atomic_t) -			\
-				sizeof(struct irq_work))
-
-struct printk_safe_seq_buf {
-	atomic_t		len;	/* length of written data */
-	atomic_t		message_lost;
-	struct irq_work		work;	/* IRQ work that flushes the buffer */
-	unsigned char		buffer[SAFE_LOG_BUF_LEN];
-};
-
-static DEFINE_PER_CPU(struct printk_safe_seq_buf, safe_print_seq);
-static DEFINE_PER_CPU(int, printk_context);
-
-#ifdef CONFIG_PRINTK_NMI
-static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq);
-#endif
-
-/* Get flushed in a more safe context. */
-static void queue_flush_work(struct printk_safe_seq_buf *s)
-{
-	if (printk_safe_irq_ready)
-		irq_work_queue(&s->work);
-}
-
-/*
- * Add a message to per-CPU context-dependent buffer. NMI and printk-safe
- * have dedicated buffers, because otherwise printk-safe preempted by
- * NMI-printk would have overwritten the NMI messages.
- *
- * The messages are flushed from irq work (or from panic()), possibly,
- * from other CPU, concurrently with printk_safe_log_store(). Should this
- * happen, printk_safe_log_store() will notice the buffer->len mismatch
- * and repeat the write.
- */
-static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s,
-						const char *fmt, va_list args)
-{
-	int add;
-	size_t len;
-	va_list ap;
-
-again:
-	len = atomic_read(&s->len);
-
-	/* The trailing '\0' is not counted into len. */
-	if (len >= sizeof(s->buffer) - 1) {
-		atomic_inc(&s->message_lost);
-		queue_flush_work(s);
-		return 0;
-	}
-
-	/*
-	 * Make sure that all old data have been read before the buffer
-	 * was reset. This is not needed when we just append data.
-	 */
-	if (!len)
-		smp_rmb();
-
-	va_copy(ap, args);
-	add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, ap);
-	va_end(ap);
-	if (!add)
-		return 0;
-
-	/*
-	 * Do it once again if the buffer has been flushed in the meantime.
-	 * Note that atomic_cmpxchg() is an implicit memory barrier that
-	 * makes sure that the data were written before updating s->len.
-	 */
-	if (atomic_cmpxchg(&s->len, len, len + add) != len)
-		goto again;
-
-	queue_flush_work(s);
-	return add;
-}
-
-static inline void printk_safe_flush_line(const char *text, int len)
-{
-	/*
-	 * Avoid any console drivers calls from here, because we may be
-	 * in NMI or printk_safe context (when in panic). The messages
-	 * must go only into the ring buffer at this stage.  Consoles will
-	 * get explicitly called later when a crashdump is not generated.
-	 */
-	printk_deferred("%.*s", len, text);
-}
-
-/* printk part of the temporary buffer line by line */
-static int printk_safe_flush_buffer(const char *start, size_t len)
-{
-	const char *c, *end;
-	bool header;
-
-	c = start;
-	end = start + len;
-	header = true;
-
-	/* Print line by line. */
-	while (c < end) {
-		if (*c == '\n') {
-			printk_safe_flush_line(start, c - start + 1);
-			start = ++c;
-			header = true;
-			continue;
-		}
-
-		/* Handle continuous lines or missing new line. */
-		if ((c + 1 < end) && printk_get_level(c)) {
-			if (header) {
-				c = printk_skip_level(c);
-				continue;
-			}
-
-			printk_safe_flush_line(start, c - start);
-			start = c++;
-			header = true;
-			continue;
-		}
-
-		header = false;
-		c++;
-	}
-
-	/* Check if there was a partial line. Ignore pure header. */
-	if (start < end && !header) {
-		static const char newline[] = KERN_CONT "\n";
-
-		printk_safe_flush_line(start, end - start);
-		printk_safe_flush_line(newline, strlen(newline));
-	}
-
-	return len;
-}
-
-static void report_message_lost(struct printk_safe_seq_buf *s)
-{
-	int lost = atomic_xchg(&s->message_lost, 0);
-
-	if (lost)
-		printk_deferred("Lost %d message(s)!\n", lost);
-}
-
-/*
- * Flush data from the associated per-CPU buffer. The function
- * can be called either via IRQ work or independently.
- */
-static void __printk_safe_flush(struct irq_work *work)
-{
-	static raw_spinlock_t read_lock =
-		__RAW_SPIN_LOCK_INITIALIZER(read_lock);
-	struct printk_safe_seq_buf *s =
-		container_of(work, struct printk_safe_seq_buf, work);
-	unsigned long flags;
-	size_t len;
-	int i;
-
-	/*
-	 * The lock has two functions. First, one reader has to flush all
-	 * available message to make the lockless synchronization with
-	 * writers easier. Second, we do not want to mix messages from
-	 * different CPUs. This is especially important when printing
-	 * a backtrace.
-	 */
-	raw_spin_lock_irqsave(&read_lock, flags);
-
-	i = 0;
-more:
-	len = atomic_read(&s->len);
-
-	/*
-	 * This is just a paranoid check that nobody has manipulated
-	 * the buffer an unexpected way. If we printed something then
-	 * @len must only increase. Also it should never overflow the
-	 * buffer size.
-	 */
-	if ((i && i >= len) || len > sizeof(s->buffer)) {
-		const char *msg = "printk_safe_flush: internal error\n";
-
-		printk_safe_flush_line(msg, strlen(msg));
-		len = 0;
-	}
-
-	if (!len)
-		goto out; /* Someone else has already flushed the buffer. */
-
-	/* Make sure that data has been written up to the @len */
-	smp_rmb();
-	i += printk_safe_flush_buffer(s->buffer + i, len - i);
-
-	/*
-	 * Check that nothing has got added in the meantime and truncate
-	 * the buffer. Note that atomic_cmpxchg() is an implicit memory
-	 * barrier that makes sure that the data were copied before
-	 * updating s->len.
-	 */
-	if (atomic_cmpxchg(&s->len, len, 0) != len)
-		goto more;
-
-out:
-	report_message_lost(s);
-	raw_spin_unlock_irqrestore(&read_lock, flags);
-}
-
-/**
- * printk_safe_flush - flush all per-cpu nmi buffers.
- *
- * The buffers are flushed automatically via IRQ work. This function
- * is useful only when someone wants to be sure that all buffers have
- * been flushed at some point.
- */
-void printk_safe_flush(void)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-#ifdef CONFIG_PRINTK_NMI
-		__printk_safe_flush(&per_cpu(nmi_print_seq, cpu).work);
-#endif
-		__printk_safe_flush(&per_cpu(safe_print_seq, cpu).work);
-	}
-}
-
-/**
- * printk_safe_flush_on_panic - flush all per-cpu nmi buffers when the system
- *	goes down.
- *
- * Similar to printk_safe_flush() but it can be called even in NMI context when
- * the system goes down. It does the best effort to get NMI messages into
- * the main ring buffer.
- *
- * Note that it could try harder when there is only one CPU online.
- */
-void printk_safe_flush_on_panic(void)
-{
-	/*
-	 * Make sure that we could access the main ring buffer.
-	 * Do not risk a double release when more CPUs are up.
-	 */
-	if (raw_spin_is_locked(&logbuf_lock)) {
-		if (num_online_cpus() > 1)
-			return;
-
-		debug_locks_off();
-		raw_spin_lock_init(&logbuf_lock);
-	}
-
-	printk_safe_flush();
-}
-
-#ifdef CONFIG_PRINTK_NMI
-/*
- * Safe printk() for NMI context. It uses a per-CPU buffer to
- * store the message. NMIs are not nested, so there is always only
- * one writer running. But the buffer might get flushed from another
- * CPU, so we need to be careful.
- */
-static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
-{
-	struct printk_safe_seq_buf *s = this_cpu_ptr(&nmi_print_seq);
-
-	return printk_safe_log_store(s, fmt, args);
-}
-
-void notrace printk_nmi_enter(void)
-{
-	this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK);
-}
-
-void notrace printk_nmi_exit(void)
-{
-	this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK);
-}
-
-/*
- * Marks a code that might produce many messages in NMI context
- * and the risk of losing them is more critical than eventual
- * reordering.
- *
- * It has effect only when called in NMI context. Then printk()
- * will try to store the messages into the main logbuf directly
- * and use the per-CPU buffers only as a fallback when the lock
- * is not available.
- */
-void printk_nmi_direct_enter(void)
-{
-	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
-		this_cpu_or(printk_context, PRINTK_NMI_DIRECT_CONTEXT_MASK);
-}
-
-void printk_nmi_direct_exit(void)
-{
-	this_cpu_and(printk_context, ~PRINTK_NMI_DIRECT_CONTEXT_MASK);
-}
-
-#else
-
-static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args)
-{
-	return 0;
-}
-
-#endif /* CONFIG_PRINTK_NMI */
-
-/*
- * Lock-less printk(), to avoid deadlocks should the printk() recurse
- * into itself. It uses a per-CPU buffer to store the message, just like
- * NMI.
- */
-static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args)
-{
-	struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq);
-
-	return printk_safe_log_store(s, fmt, args);
-}
-
-/* Can be preempted by NMI. */
-void __printk_safe_enter(void)
-{
-	this_cpu_inc(printk_context);
-}
-
-/* Can be preempted by NMI. */
-void __printk_safe_exit(void)
-{
-	this_cpu_dec(printk_context);
-}
-
-__printf(1, 0) int vprintk_func(const char *fmt, va_list args)
-{
-	/*
-	 * Try to use the main logbuf even in NMI. But avoid calling console
-	 * drivers that might have their own locks.
-	 */
-	if ((this_cpu_read(printk_context) & PRINTK_NMI_DIRECT_CONTEXT_MASK) &&
-	    raw_spin_trylock(&logbuf_lock)) {
-		int len;
-
-		len = vprintk_store(0, LOGLEVEL_DEFAULT, NULL, 0, fmt, args);
-		raw_spin_unlock(&logbuf_lock);
-		defer_console_output();
-		return len;
-	}
-
-	/* Use extra buffer in NMI when logbuf_lock is taken or in safe mode. */
-	if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK)
-		return vprintk_nmi(fmt, args);
-
-	/* Use extra buffer to prevent a recursion deadlock in safe mode. */
-	if (this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK)
-		return vprintk_safe(fmt, args);
-
-	/* No obstacles. */
-	return vprintk_default(fmt, args);
-}
-
-void __init printk_safe_init(void)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-		struct printk_safe_seq_buf *s;
-
-		s = &per_cpu(safe_print_seq, cpu);
-		init_irq_work(&s->work, __printk_safe_flush);
-
-#ifdef CONFIG_PRINTK_NMI
-		s = &per_cpu(nmi_print_seq, cpu);
-		init_irq_work(&s->work, __printk_safe_flush);
-#endif
-	}
-
-	/*
-	 * In the highly unlikely event that a NMI were to trigger at
-	 * this moment. Make sure IRQ work is set up before this
-	 * variable is set.
-	 */
-	barrier();
-	printk_safe_irq_ready = 1;
-
-	/* Flush pending messages that did not have scheduled IRQ works. */
-	printk_safe_flush();
-}
Index: linux-5.4.5-rt3/kernel/ptrace.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/ptrace.c
+++ linux-5.4.5-rt3/kernel/ptrace.c
@@ -180,7 +180,14 @@ static bool ptrace_freeze_traced(struct
 
 	spin_lock_irq(&task->sighand->siglock);
 	if (task_is_traced(task) && !__fatal_signal_pending(task)) {
-		task->state = __TASK_TRACED;
+		unsigned long flags;
+
+		raw_spin_lock_irqsave(&task->pi_lock, flags);
+		if (task->state & __TASK_TRACED)
+			task->state = __TASK_TRACED;
+		else
+			task->saved_state = __TASK_TRACED;
+		raw_spin_unlock_irqrestore(&task->pi_lock, flags);
 		ret = true;
 	}
 	spin_unlock_irq(&task->sighand->siglock);
Index: linux-5.4.5-rt3/kernel/rcu/Kconfig
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/Kconfig
+++ linux-5.4.5-rt3/kernel/rcu/Kconfig
@@ -161,8 +161,8 @@ config RCU_FAST_NO_HZ
 
 config RCU_BOOST
 	bool "Enable RCU priority boosting"
-	depends on RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT
-	default n
+	depends on (RT_MUTEXES && PREEMPT_RCU && RCU_EXPERT) || PREEMPT_RT
+	default y if PREEMPT_RT
 	help
 	  This option boosts the priority of preempted RCU readers that
 	  block the current preemptible RCU grace period for too long.
@@ -200,8 +200,8 @@ config RCU_NOCB_CPU
 	  specified at boot time by the rcu_nocbs parameter.  For each
 	  such CPU, a kthread ("rcuox/N") will be created to invoke
 	  callbacks, where the "N" is the CPU being offloaded, and where
-	  the "p" for RCU-preempt (PREEMPT kernels) and "s" for RCU-sched
-	  (!PREEMPT kernels).  Nothing prevents this kthread from running
+	  the "p" for RCU-preempt (PREEMPTION kernels) and "s" for RCU-sched
+	  (!PREEMPTION kernels).  Nothing prevents this kthread from running
 	  on the specified CPUs, but (1) the kthreads may be preempted
 	  between each callback, and (2) affinity or cgroups can be used
 	  to force the kthreads to run on whatever set of CPUs is desired.
Index: linux-5.4.5-rt3/kernel/rcu/rcutorture.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/rcutorture.c
+++ linux-5.4.5-rt3/kernel/rcu/rcutorture.c
@@ -60,10 +60,13 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck
 #define RCUTORTURE_RDR_RBH	 0x08	/*  ... rcu_read_lock_bh(). */
 #define RCUTORTURE_RDR_SCHED	 0x10	/*  ... rcu_read_lock_sched(). */
 #define RCUTORTURE_RDR_RCU	 0x20	/*  ... entering another RCU reader. */
-#define RCUTORTURE_RDR_NBITS	 6	/* Number of bits defined above. */
+#define RCUTORTURE_RDR_ATOM_BH	 0x40	/*  ... disabling bh while atomic */
+#define RCUTORTURE_RDR_ATOM_RBH	 0x80	/*  ... RBH while atomic */
+#define RCUTORTURE_RDR_NBITS	 8	/* Number of bits defined above. */
 #define RCUTORTURE_MAX_EXTEND	 \
 	(RCUTORTURE_RDR_BH | RCUTORTURE_RDR_IRQ | RCUTORTURE_RDR_PREEMPT | \
-	 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED)
+	 RCUTORTURE_RDR_RBH | RCUTORTURE_RDR_SCHED | \
+	 RCUTORTURE_RDR_ATOM_BH | RCUTORTURE_RDR_ATOM_RBH)
 #define RCUTORTURE_RDR_MAX_LOOPS 0x7	/* Maximum reader extensions. */
 					/* Must be power of two minus one. */
 #define RCUTORTURE_RDR_MAX_SEGS (RCUTORTURE_RDR_MAX_LOOPS + 3)
@@ -1152,31 +1155,52 @@ static void rcutorture_one_extend(int *r
 	WARN_ON_ONCE((idxold >> RCUTORTURE_RDR_SHIFT) > 1);
 	rtrsp->rt_readstate = newstate;
 
-	/* First, put new protection in place to avoid critical-section gap. */
+	/*
+	 * First, put new protection in place to avoid critical-section gap.
+	 * Disable preemption around the ATOM disables to ensure that
+	 * in_atomic() is true.
+	 */
 	if (statesnew & RCUTORTURE_RDR_BH)
 		local_bh_disable();
+	if (statesnew & RCUTORTURE_RDR_RBH)
+		rcu_read_lock_bh();
 	if (statesnew & RCUTORTURE_RDR_IRQ)
 		local_irq_disable();
 	if (statesnew & RCUTORTURE_RDR_PREEMPT)
 		preempt_disable();
-	if (statesnew & RCUTORTURE_RDR_RBH)
-		rcu_read_lock_bh();
 	if (statesnew & RCUTORTURE_RDR_SCHED)
 		rcu_read_lock_sched();
+	preempt_disable();
+	if (statesnew & RCUTORTURE_RDR_ATOM_BH)
+		local_bh_disable();
+	if (statesnew & RCUTORTURE_RDR_ATOM_RBH)
+		rcu_read_lock_bh();
+	preempt_enable();
 	if (statesnew & RCUTORTURE_RDR_RCU)
 		idxnew = cur_ops->readlock() << RCUTORTURE_RDR_SHIFT;
 
-	/* Next, remove old protection, irq first due to bh conflict. */
+	/*
+	 * Next, remove old protection, in decreasing order of strength
+	 * to avoid unlock paths that aren't safe in the stronger
+	 * context.  Disable preemption around the ATOM enables in
+	 * case the context was only atomic due to IRQ disabling.
+	 */
+	preempt_disable();
 	if (statesold & RCUTORTURE_RDR_IRQ)
 		local_irq_enable();
-	if (statesold & RCUTORTURE_RDR_BH)
+	if (statesold & RCUTORTURE_RDR_ATOM_BH)
 		local_bh_enable();
+	if (statesold & RCUTORTURE_RDR_ATOM_RBH)
+		rcu_read_unlock_bh();
+	preempt_enable();
 	if (statesold & RCUTORTURE_RDR_PREEMPT)
 		preempt_enable();
-	if (statesold & RCUTORTURE_RDR_RBH)
-		rcu_read_unlock_bh();
 	if (statesold & RCUTORTURE_RDR_SCHED)
 		rcu_read_unlock_sched();
+	if (statesold & RCUTORTURE_RDR_BH)
+		local_bh_enable();
+	if (statesold & RCUTORTURE_RDR_RBH)
+		rcu_read_unlock_bh();
 	if (statesold & RCUTORTURE_RDR_RCU)
 		cur_ops->readunlock(idxold >> RCUTORTURE_RDR_SHIFT);
 
@@ -1212,6 +1236,12 @@ rcutorture_extend_mask(int oldmask, stru
 	int mask = rcutorture_extend_mask_max();
 	unsigned long randmask1 = torture_random(trsp) >> 8;
 	unsigned long randmask2 = randmask1 >> 3;
+	unsigned long preempts = RCUTORTURE_RDR_PREEMPT | RCUTORTURE_RDR_SCHED;
+	unsigned long preempts_irq = preempts | RCUTORTURE_RDR_IRQ;
+	unsigned long nonatomic_bhs = RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
+	unsigned long atomic_bhs = RCUTORTURE_RDR_ATOM_BH |
+				   RCUTORTURE_RDR_ATOM_RBH;
+	unsigned long tmp;
 
 	WARN_ON_ONCE(mask >> RCUTORTURE_RDR_SHIFT);
 	/* Mostly only one bit (need preemption!), sometimes lots of bits. */
@@ -1219,11 +1249,49 @@ rcutorture_extend_mask(int oldmask, stru
 		mask = mask & randmask2;
 	else
 		mask = mask & (1 << (randmask2 % RCUTORTURE_RDR_NBITS));
-	/* Can't enable bh w/irq disabled. */
-	if ((mask & RCUTORTURE_RDR_IRQ) &&
-	    ((!(mask & RCUTORTURE_RDR_BH) && (oldmask & RCUTORTURE_RDR_BH)) ||
-	     (!(mask & RCUTORTURE_RDR_RBH) && (oldmask & RCUTORTURE_RDR_RBH))))
-		mask |= RCUTORTURE_RDR_BH | RCUTORTURE_RDR_RBH;
+
+	/*
+	 * Can't enable bh w/irq disabled.
+	 */
+	tmp = atomic_bhs | nonatomic_bhs;
+	if (mask & RCUTORTURE_RDR_IRQ)
+		mask |= oldmask & tmp;
+
+	/*
+	 * Ideally these sequences would be detected in debug builds
+	 * (regardless of RT), but until then don't stop testing
+	 * them on non-RT.
+	 */
+	if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
+		/*
+		 * Can't release the outermost rcu lock in an irq disabled
+		 * section without preemption also being disabled, if irqs
+		 * had ever been enabled during this RCU critical section
+		 * (could leak a special flag and delay reporting the qs).
+		 */
+		if ((oldmask & RCUTORTURE_RDR_RCU) &&
+		    (mask & RCUTORTURE_RDR_IRQ) &&
+		    !(mask & preempts))
+			mask |= RCUTORTURE_RDR_RCU;
+
+		/* Can't modify atomic bh in non-atomic context */
+		if ((oldmask & atomic_bhs) && (mask & atomic_bhs) &&
+		    !(mask & preempts_irq)) {
+			mask |= oldmask & preempts_irq;
+			if (mask & RCUTORTURE_RDR_IRQ)
+				mask |= oldmask & tmp;
+		}
+		if ((mask & atomic_bhs) && !(mask & preempts_irq))
+			mask |= RCUTORTURE_RDR_PREEMPT;
+
+		/* Can't modify non-atomic bh in atomic context */
+		tmp = nonatomic_bhs;
+		if (oldmask & preempts_irq)
+			mask &= ~tmp;
+		if ((oldmask | mask) & preempts_irq)
+			mask |= oldmask & tmp;
+	}
+
 	return mask ?: RCUTORTURE_RDR_RCU;
 }
 
@@ -1725,7 +1793,7 @@ static void rcu_torture_fwd_cb_cr(struct
 // Give the scheduler a chance, even on nohz_full CPUs.
 static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
 {
-	if (IS_ENABLED(CONFIG_PREEMPT) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+	if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
 		// Real call_rcu() floods hit userspace, so emulate that.
 		if (need_resched() || (iter & 0xfff))
 			schedule();
Index: linux-5.4.5-rt3/kernel/rcu/srcutiny.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/srcutiny.c
+++ linux-5.4.5-rt3/kernel/rcu/srcutiny.c
@@ -103,7 +103,7 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock);
 
 /*
  * Workqueue handler to drive one grace period and invoke any callbacks
- * that become ready as a result.  Single-CPU and !PREEMPT operation
+ * that become ready as a result.  Single-CPU and !PREEMPTION operation
  * means that we get away with murder on synchronization.  ;-)
  */
 void srcu_drive_gp(struct work_struct *wp)
Index: linux-5.4.5-rt3/kernel/rcu/srcutree.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/srcutree.c
+++ linux-5.4.5-rt3/kernel/rcu/srcutree.c
@@ -25,6 +25,7 @@
 #include <linux/delay.h>
 #include <linux/module.h>
 #include <linux/srcu.h>
+#include <linux/locallock.h>
 
 #include "rcu.h"
 #include "rcu_segcblist.h"
@@ -735,6 +736,7 @@ static void srcu_flip(struct srcu_struct
 	smp_mb(); /* D */  /* Pairs with C. */
 }
 
+static DEFINE_LOCAL_IRQ_LOCK(sp_llock);
 /*
  * If SRCU is likely idle, return true, otherwise return false.
  *
@@ -764,13 +766,13 @@ static bool srcu_might_be_idle(struct sr
 	unsigned long t;
 
 	/* If the local srcu_data structure has callbacks, not idle.  */
-	local_irq_save(flags);
+	local_lock_irqsave(sp_llock, flags);
 	sdp = this_cpu_ptr(ssp->sda);
 	if (rcu_segcblist_pend_cbs(&sdp->srcu_cblist)) {
-		local_irq_restore(flags);
+		local_unlock_irqrestore(sp_llock, flags);
 		return false; /* Callbacks already present, so not idle. */
 	}
-	local_irq_restore(flags);
+	local_unlock_irqrestore(sp_llock, flags);
 
 	/*
 	 * No local callbacks, so probabalistically probe global state.
@@ -850,7 +852,7 @@ static void __call_srcu(struct srcu_stru
 	}
 	rhp->func = func;
 	idx = srcu_read_lock(ssp);
-	local_irq_save(flags);
+	local_lock_irqsave(sp_llock, flags);
 	sdp = this_cpu_ptr(ssp->sda);
 	spin_lock_rcu_node(sdp);
 	rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp, false);
@@ -866,7 +868,8 @@ static void __call_srcu(struct srcu_stru
 		sdp->srcu_gp_seq_needed_exp = s;
 		needexp = true;
 	}
-	spin_unlock_irqrestore_rcu_node(sdp, flags);
+	spin_unlock_rcu_node(sdp);
+	local_unlock_irqrestore(sp_llock, flags);
 	if (needgp)
 		srcu_funnel_gp_start(ssp, sdp, s, do_norm);
 	else if (needexp)
Index: linux-5.4.5-rt3/kernel/rcu/tree.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/tree.c
+++ linux-5.4.5-rt3/kernel/rcu/tree.c
@@ -100,8 +100,10 @@ struct rcu_state rcu_state = {
 static bool dump_tree;
 module_param(dump_tree, bool, 0444);
 /* By default, use RCU_SOFTIRQ instead of rcuc kthreads. */
-static bool use_softirq = 1;
+static bool use_softirq = !IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
 module_param(use_softirq, bool, 0444);
+#endif
 /* Control rcu_node-tree auto-balancing at boot time. */
 static bool rcu_fanout_exact;
 module_param(rcu_fanout_exact, bool, 0444);
@@ -1094,6 +1096,7 @@ static int rcu_implicit_dynticks_qs(stru
 		    !rdp->rcu_iw_pending && rdp->rcu_iw_gp_seq != rnp->gp_seq &&
 		    (rnp->ffmask & rdp->grpmask)) {
 			init_irq_work(&rdp->rcu_iw, rcu_iw_handler);
+			rdp->rcu_iw.flags = IRQ_WORK_HARD_IRQ;
 			rdp->rcu_iw_pending = true;
 			rdp->rcu_iw_gp_seq = rnp->gp_seq;
 			irq_work_queue_on(&rdp->rcu_iw, rdp->cpu);
@@ -2667,9 +2670,9 @@ EXPORT_SYMBOL_GPL(kfree_call_rcu);
 
 /*
  * During early boot, any blocking grace-period wait automatically
- * implies a grace period.  Later on, this is never the case for PREEMPT.
+ * implies a grace period.  Later on, this is never the case for PREEMPTION.
  *
- * Howevr, because a context switch is a grace period for !PREEMPT, any
+ * Howevr, because a context switch is a grace period for !PREEMPTION, any
  * blocking grace-period wait automatically implies a grace period if
  * there is only one CPU online at any point time during execution of
  * either synchronize_rcu() or synchronize_rcu_expedited().  It is OK to
Index: linux-5.4.5-rt3/kernel/rcu/tree_exp.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/tree_exp.h
+++ linux-5.4.5-rt3/kernel/rcu/tree_exp.h
@@ -670,7 +670,7 @@ static void rcu_exp_handler(void *unused
 	}
 }
 
-/* PREEMPT=y, so no PREEMPT=n expedited grace period to clean up after. */
+/* PREEMPTION=y, so no PREEMPTION=n expedited grace period to clean up after. */
 static void sync_sched_exp_online_cleanup(int cpu)
 {
 }
Index: linux-5.4.5-rt3/kernel/rcu/tree_plugin.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/tree_plugin.h
+++ linux-5.4.5-rt3/kernel/rcu/tree_plugin.h
@@ -287,10 +287,14 @@ void rcu_note_context_switch(bool preemp
 	struct task_struct *t = current;
 	struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
 	struct rcu_node *rnp;
+	int sleeping_l = 0;
 
 	trace_rcu_utilization(TPS("Start context switch"));
 	lockdep_assert_irqs_disabled();
-	WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0);
+#if defined(CONFIG_PREEMPT_RT)
+	sleeping_l = t->sleeping_lock;
+#endif
+	WARN_ON_ONCE(!preempt && t->rcu_read_lock_nesting > 0 && !sleeping_l);
 	if (t->rcu_read_lock_nesting > 0 &&
 	    !t->rcu_read_unlock_special.b.blocked) {
 
@@ -788,7 +792,7 @@ static void __init rcu_bootup_announce(v
 }
 
 /*
- * Note a quiescent state for PREEMPT=n.  Because we do not need to know
+ * Note a quiescent state for PREEMPTION=n.  Because we do not need to know
  * how many quiescent states passed, just if there was at least one since
  * the start of the grace period, this just sets a flag.  The caller must
  * have disabled preemption.
@@ -838,7 +842,7 @@ void rcu_all_qs(void)
 EXPORT_SYMBOL_GPL(rcu_all_qs);
 
 /*
- * Note a PREEMPT=n context switch.  The caller must have disabled interrupts.
+ * Note a PREEMPTION=n context switch.  The caller must have disabled interrupts.
  */
 void rcu_note_context_switch(bool preempt)
 {
Index: linux-5.4.5-rt3/kernel/rcu/update.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/rcu/update.c
+++ linux-5.4.5-rt3/kernel/rcu/update.c
@@ -55,8 +55,10 @@ extern int rcu_expedited; /* from sysctl
 module_param(rcu_expedited, int, 0);
 extern int rcu_normal; /* from sysctl */
 module_param(rcu_normal, int, 0);
-static int rcu_normal_after_boot;
+static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT);
+#ifndef CONFIG_PREEMPT_RT
 module_param(rcu_normal_after_boot, int, 0);
+#endif
 #endif /* #ifndef CONFIG_TINY_RCU */
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
Index: linux-5.4.5-rt3/kernel/sched/completion.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/completion.c
+++ linux-5.4.5-rt3/kernel/sched/completion.c
@@ -29,12 +29,12 @@ void complete(struct completion *x)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
 
 	if (x->done != UINT_MAX)
 		x->done++;
-	__wake_up_locked(&x->wait, TASK_NORMAL, 1);
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	swake_up_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 }
 EXPORT_SYMBOL(complete);
 
@@ -58,10 +58,10 @@ void complete_all(struct completion *x)
 {
 	unsigned long flags;
 
-	spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
 	x->done = UINT_MAX;
-	__wake_up_locked(&x->wait, TASK_NORMAL, 0);
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	swake_up_all_locked(&x->wait);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 }
 EXPORT_SYMBOL(complete_all);
 
@@ -70,20 +70,20 @@ do_wait_for_common(struct completion *x,
 		   long (*action)(long), long timeout, int state)
 {
 	if (!x->done) {
-		DECLARE_WAITQUEUE(wait, current);
+		DECLARE_SWAITQUEUE(wait);
 
-		__add_wait_queue_entry_tail_exclusive(&x->wait, &wait);
 		do {
 			if (signal_pending_state(state, current)) {
 				timeout = -ERESTARTSYS;
 				break;
 			}
+			__prepare_to_swait(&x->wait, &wait);
 			__set_current_state(state);
-			spin_unlock_irq(&x->wait.lock);
+			raw_spin_unlock_irq(&x->wait.lock);
 			timeout = action(timeout);
-			spin_lock_irq(&x->wait.lock);
+			raw_spin_lock_irq(&x->wait.lock);
 		} while (!x->done && timeout);
-		__remove_wait_queue(&x->wait, &wait);
+		__finish_swait(&x->wait, &wait);
 		if (!x->done)
 			return timeout;
 	}
@@ -100,9 +100,9 @@ __wait_for_common(struct completion *x,
 
 	complete_acquire(x);
 
-	spin_lock_irq(&x->wait.lock);
+	raw_spin_lock_irq(&x->wait.lock);
 	timeout = do_wait_for_common(x, action, timeout, state);
-	spin_unlock_irq(&x->wait.lock);
+	raw_spin_unlock_irq(&x->wait.lock);
 
 	complete_release(x);
 
@@ -291,12 +291,12 @@ bool try_wait_for_completion(struct comp
 	if (!READ_ONCE(x->done))
 		return false;
 
-	spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
 	if (!x->done)
 		ret = false;
 	else if (x->done != UINT_MAX)
 		x->done--;
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 	return ret;
 }
 EXPORT_SYMBOL(try_wait_for_completion);
@@ -322,8 +322,8 @@ bool completion_done(struct completion *
 	 * otherwise we can end up freeing the completion before complete()
 	 * is done referencing it.
 	 */
-	spin_lock_irqsave(&x->wait.lock, flags);
-	spin_unlock_irqrestore(&x->wait.lock, flags);
+	raw_spin_lock_irqsave(&x->wait.lock, flags);
+	raw_spin_unlock_irqrestore(&x->wait.lock, flags);
 	return true;
 }
 EXPORT_SYMBOL(completion_done);
Index: linux-5.4.5-rt3/kernel/sched/core.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/core.c
+++ linux-5.4.5-rt3/kernel/sched/core.c
@@ -56,7 +56,11 @@ const_debug unsigned int sysctl_sched_fe
  * Number of tasks to iterate in a single balance run.
  * Limited because this is done with IRQs disabled.
  */
+#ifdef CONFIG_PREEMPT_RT
+const_debug unsigned int sysctl_sched_nr_migrate = 8;
+#else
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
+#endif
 
 /*
  * period over which we measure -rt task CPU usage in us.
@@ -410,9 +414,15 @@ static bool set_nr_if_polling(struct tas
 #endif
 #endif
 
-static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
+static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task,
+			 bool sleeper)
 {
-	struct wake_q_node *node = &task->wake_q;
+	struct wake_q_node *node;
+
+	if (sleeper)
+		node = &task->wake_q_sleeper;
+	else
+		node = &task->wake_q;
 
 	/*
 	 * Atomically grab the task, if ->wake_q is !nil already it means
@@ -448,7 +458,13 @@ static bool __wake_q_add(struct wake_q_h
  */
 void wake_q_add(struct wake_q_head *head, struct task_struct *task)
 {
-	if (__wake_q_add(head, task))
+	if (__wake_q_add(head, task, false))
+		get_task_struct(task);
+}
+
+void wake_q_add_sleeper(struct wake_q_head *head, struct task_struct *task)
+{
+	if (__wake_q_add(head, task, true))
 		get_task_struct(task);
 }
 
@@ -471,28 +487,39 @@ void wake_q_add(struct wake_q_head *head
  */
 void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
 {
-	if (!__wake_q_add(head, task))
+	if (!__wake_q_add(head, task, false))
 		put_task_struct(task);
 }
 
-void wake_up_q(struct wake_q_head *head)
+void __wake_up_q(struct wake_q_head *head, bool sleeper)
 {
 	struct wake_q_node *node = head->first;
 
 	while (node != WAKE_Q_TAIL) {
 		struct task_struct *task;
 
-		task = container_of(node, struct task_struct, wake_q);
+		if (sleeper)
+			task = container_of(node, struct task_struct, wake_q_sleeper);
+		else
+			task = container_of(node, struct task_struct, wake_q);
+
 		BUG_ON(!task);
 		/* Task can safely be re-inserted now: */
 		node = node->next;
-		task->wake_q.next = NULL;
 
+		if (sleeper)
+			task->wake_q_sleeper.next = NULL;
+		else
+			task->wake_q.next = NULL;
 		/*
 		 * wake_up_process() executes a full barrier, which pairs with
 		 * the queueing in wake_q_add() so as not to miss wakeups.
 		 */
-		wake_up_process(task);
+		if (sleeper)
+			wake_up_lock_sleeper(task);
+		else
+			wake_up_process(task);
+
 		put_task_struct(task);
 	}
 }
@@ -528,6 +555,48 @@ void resched_curr(struct rq *rq)
 		trace_sched_wake_idle_without_ipi(cpu);
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+
+static int tsk_is_polling(struct task_struct *p)
+{
+#ifdef TIF_POLLING_NRFLAG
+	return test_tsk_thread_flag(p, TIF_POLLING_NRFLAG);
+#else
+	return 0;
+#endif
+}
+
+void resched_curr_lazy(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	int cpu;
+
+	if (!sched_feat(PREEMPT_LAZY)) {
+		resched_curr(rq);
+		return;
+	}
+
+	lockdep_assert_held(&rq->lock);
+
+	if (test_tsk_need_resched(curr))
+		return;
+
+	if (test_tsk_need_resched_lazy(curr))
+		return;
+
+	set_tsk_need_resched_lazy(curr);
+
+	cpu = cpu_of(rq);
+	if (cpu == smp_processor_id())
+		return;
+
+	/* NEED_RESCHED_LAZY must be visible before we test polling */
+	smp_mb();
+	if (!tsk_is_polling(curr))
+		smp_send_reschedule(cpu);
+}
+#endif
+
 void resched_cpu(int cpu)
 {
 	struct rq *rq = cpu_rq(cpu);
@@ -1460,7 +1529,7 @@ static inline bool is_cpu_allowed(struct
 	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
 		return false;
 
-	if (is_per_cpu_kthread(p))
+	if (is_per_cpu_kthread(p) || __migrate_disabled(p))
 		return cpu_online(cpu);
 
 	return cpu_active(cpu);
@@ -1509,6 +1578,7 @@ static struct rq *move_queued_task(struc
 struct migration_arg {
 	struct task_struct *task;
 	int dest_cpu;
+	bool done;
 };
 
 /*
@@ -1544,6 +1614,11 @@ static int migration_cpu_stop(void *data
 	struct task_struct *p = arg->task;
 	struct rq *rq = this_rq();
 	struct rq_flags rf;
+	int dest_cpu = arg->dest_cpu;
+
+	/* We don't look at arg after this point. */
+	smp_mb();
+	arg->done = true;
 
 	/*
 	 * The original target CPU might have gone down and we might
@@ -1566,9 +1641,9 @@ static int migration_cpu_stop(void *data
 	 */
 	if (task_rq(p) == rq) {
 		if (task_on_rq_queued(p))
-			rq = __migrate_task(rq, &rf, p, arg->dest_cpu);
+			rq = __migrate_task(rq, &rf, p, dest_cpu);
 		else
-			p->wake_cpu = arg->dest_cpu;
+			p->wake_cpu = dest_cpu;
 	}
 	rq_unlock(rq, &rf);
 	raw_spin_unlock(&p->pi_lock);
@@ -1584,9 +1659,18 @@ static int migration_cpu_stop(void *data
 void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
 {
 	cpumask_copy(&p->cpus_mask, new_mask);
-	p->nr_cpus_allowed = cpumask_weight(new_mask);
+	if (p->cpus_ptr == &p->cpus_mask)
+		p->nr_cpus_allowed = cpumask_weight(new_mask);
 }
 
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+int __migrate_disabled(struct task_struct *p)
+{
+	return p->migrate_disable;
+}
+EXPORT_SYMBOL_GPL(__migrate_disabled);
+#endif
+
 void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
 {
 	struct rq *rq = task_rq(p);
@@ -1653,7 +1737,7 @@ static int __set_cpus_allowed_ptr(struct
 		goto out;
 	}
 
-	if (cpumask_equal(p->cpus_ptr, new_mask))
+	if (cpumask_equal(&p->cpus_mask, new_mask))
 		goto out;
 
 	dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
@@ -1675,7 +1759,8 @@ static int __set_cpus_allowed_ptr(struct
 	}
 
 	/* Can the task run on the task's current CPU? If so, we're done */
-	if (cpumask_test_cpu(task_cpu(p), new_mask))
+	if (cpumask_test_cpu(task_cpu(p), new_mask) ||
+	    p->cpus_ptr != &p->cpus_mask)
 		goto out;
 
 	if (task_running(rq, p) || p->state == TASK_WAKING) {
@@ -1872,6 +1957,18 @@ out:
 }
 #endif /* CONFIG_NUMA_BALANCING */
 
+static bool check_task_state(struct task_struct *p, long match_state)
+{
+	bool match = false;
+
+	raw_spin_lock_irq(&p->pi_lock);
+	if (p->state == match_state || p->saved_state == match_state)
+		match = true;
+	raw_spin_unlock_irq(&p->pi_lock);
+
+	return match;
+}
+
 /*
  * wait_task_inactive - wait for a thread to unschedule.
  *
@@ -1916,7 +2013,7 @@ unsigned long wait_task_inactive(struct
 		 * is actually now running somewhere else!
 		 */
 		while (task_running(rq, p)) {
-			if (match_state && unlikely(p->state != match_state))
+			if (match_state && !check_task_state(p, match_state))
 				return 0;
 			cpu_relax();
 		}
@@ -1931,7 +2028,8 @@ unsigned long wait_task_inactive(struct
 		running = task_running(rq, p);
 		queued = task_on_rq_queued(p);
 		ncsw = 0;
-		if (!match_state || p->state == match_state)
+		if (!match_state || p->state == match_state ||
+		    p->saved_state == match_state)
 			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
 		task_rq_unlock(rq, p, &rf);
 
@@ -2519,6 +2617,8 @@ try_to_wake_up(struct task_struct *p, un
 	int cpu, success = 0;
 
 	preempt_disable();
+
+#ifndef CONFIG_PREEMPT_RT
 	if (p == current) {
 		/*
 		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
@@ -2541,7 +2641,7 @@ try_to_wake_up(struct task_struct *p, un
 		trace_sched_wakeup(p);
 		goto out;
 	}
-
+#endif
 	/*
 	 * If we are going to wake up a thread waiting for CONDITION we
 	 * need to ensure that CONDITION=1 done by the caller can not be
@@ -2550,8 +2650,27 @@ try_to_wake_up(struct task_struct *p, un
 	 */
 	raw_spin_lock_irqsave(&p->pi_lock, flags);
 	smp_mb__after_spinlock();
-	if (!(p->state & state))
-		goto unlock;
+	if (!(p->state & state)) {
+		/*
+		 * The task might be running due to a spinlock sleeper
+		 * wakeup. Check the saved state and set it to running
+		 * if the wakeup condition is true.
+		 */
+		if (!(wake_flags & WF_LOCK_SLEEPER)) {
+			if (p->saved_state & state) {
+				p->saved_state = TASK_RUNNING;
+				success = 1;
+			}
+		}
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		goto out_nostat;
+	}
+	/*
+	 * If this is a regular wakeup, then we can unconditionally
+	 * clear the saved state of a "lock sleeper".
+	 */
+	if (!(wake_flags & WF_LOCK_SLEEPER))
+		p->saved_state = TASK_RUNNING;
 
 	trace_sched_waking(p);
 
@@ -2643,9 +2762,12 @@ try_to_wake_up(struct task_struct *p, un
 	ttwu_queue(p, cpu, wake_flags);
 unlock:
 	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+#ifndef CONFIG_PREEMPT_RT
 out:
+#endif
 	if (success)
 		ttwu_stat(p, cpu, wake_flags);
+out_nostat:
 	preempt_enable();
 
 	return success;
@@ -2668,6 +2790,18 @@ int wake_up_process(struct task_struct *
 }
 EXPORT_SYMBOL(wake_up_process);
 
+/**
+ * wake_up_lock_sleeper - Wake up a specific process blocked on a "sleeping lock"
+ * @p: The process to be woken up.
+ *
+ * Same as wake_up_process() above, but wake_flags=WF_LOCK_SLEEPER to indicate
+ * the nature of the wakeup.
+ */
+int wake_up_lock_sleeper(struct task_struct *p)
+{
+	return try_to_wake_up(p, TASK_UNINTERRUPTIBLE, WF_LOCK_SLEEPER);
+}
+
 int wake_up_state(struct task_struct *p, unsigned int state)
 {
 	return try_to_wake_up(p, state, 0);
@@ -2910,6 +3044,9 @@ int sched_fork(unsigned long clone_flags
 	p->on_cpu = 0;
 #endif
 	init_task_preempt_count(p);
+#ifdef CONFIG_HAVE_PREEMPT_LAZY
+	task_thread_info(p)->preempt_lazy_count = 0;
+#endif
 #ifdef CONFIG_SMP
 	plist_node_init(&p->pushable_tasks, MAX_PRIO);
 	RB_CLEAR_NODE(&p->pushable_dl_tasks);
@@ -3237,23 +3374,18 @@ static struct rq *finish_task_switch(str
 	 *   provided by mmdrop(),
 	 * - a sync_core for SYNC_CORE.
 	 */
+	/*
+	 * We use mmdrop_delayed() here so we don't have to do the
+	 * full __mmdrop() when we are the last user.
+	 */
 	if (mm) {
 		membarrier_mm_sync_core_before_usermode(mm);
-		mmdrop(mm);
+		mmdrop_delayed(mm);
 	}
 	if (unlikely(prev_state == TASK_DEAD)) {
 		if (prev->sched_class->task_dead)
 			prev->sched_class->task_dead(prev);
 
-		/*
-		 * Remove function-return probe instances associated with this
-		 * task and put them back on the free list.
-		 */
-		kprobe_flush_task(prev);
-
-		/* Task is done with its stack. */
-		put_task_stack(prev);
-
 		put_task_struct_rcu_user(prev);
 	}
 
@@ -3956,6 +4088,8 @@ restart:
 	BUG();
 }
 
+static void migrate_disabled_sched(struct task_struct *p);
+
 /*
  * __schedule() is the main scheduler function.
  *
@@ -4026,6 +4160,9 @@ static void __sched notrace __schedule(b
 	rq_lock(rq, &rf);
 	smp_mb__after_spinlock();
 
+	if (__migrate_disabled(prev))
+		migrate_disabled_sched(prev);
+
 	/* Promote REQ to ACT */
 	rq->clock_update_flags <<= 1;
 	update_rq_clock(rq);
@@ -4047,6 +4184,7 @@ static void __sched notrace __schedule(b
 
 	next = pick_next_task(rq, prev, &rf);
 	clear_tsk_need_resched(prev);
+	clear_tsk_need_resched_lazy(prev);
 	clear_preempt_need_resched();
 
 	if (likely(prev != next)) {
@@ -4234,6 +4372,30 @@ static void __sched notrace preempt_sche
 	} while (need_resched());
 }
 
+#ifdef CONFIG_PREEMPT_LAZY
+/*
+ * If TIF_NEED_RESCHED is then we allow to be scheduled away since this is
+ * set by a RT task. Oterwise we try to avoid beeing scheduled out as long as
+ * preempt_lazy_count counter >0.
+ */
+static __always_inline int preemptible_lazy(void)
+{
+	if (test_thread_flag(TIF_NEED_RESCHED))
+		return 1;
+	if (current_thread_info()->preempt_lazy_count)
+		return 0;
+	return 1;
+}
+
+#else
+
+static inline int preemptible_lazy(void)
+{
+	return 1;
+}
+
+#endif
+
 #ifdef CONFIG_PREEMPTION
 /*
  * This is the entry point to schedule() from in-kernel preemption
@@ -4247,7 +4409,8 @@ asmlinkage __visible void __sched notrac
 	 */
 	if (likely(!preemptible()))
 		return;
-
+	if (!preemptible_lazy())
+		return;
 	preempt_schedule_common();
 }
 NOKPROBE_SYMBOL(preempt_schedule);
@@ -4274,6 +4437,9 @@ asmlinkage __visible void __sched notrac
 	if (likely(!preemptible()))
 		return;
 
+	if (!preemptible_lazy())
+		return;
+
 	do {
 		/*
 		 * Because the function tracer can trace preempt_count_sub()
@@ -6064,7 +6230,9 @@ void init_idle(struct task_struct *idle,
 
 	/* Set the preempt count _outside_ the spinlocks! */
 	init_idle_preempt_count(idle, cpu);
-
+#ifdef CONFIG_HAVE_PREEMPT_LAZY
+	task_thread_info(idle)->preempt_lazy_count = 0;
+#endif
 	/*
 	 * The idle tasks have their own, simple scheduling class:
 	 */
@@ -6169,6 +6337,8 @@ void sched_setnuma(struct task_struct *p
 #endif /* CONFIG_NUMA_BALANCING */
 
 #ifdef CONFIG_HOTPLUG_CPU
+static DEFINE_PER_CPU(struct mm_struct *, idle_last_mm);
+
 /*
  * Ensure that the idle task is using init_mm right before its CPU goes
  * offline.
@@ -6184,7 +6354,11 @@ void idle_task_exit(void)
 		current->active_mm = &init_mm;
 		finish_arch_post_lock_switch();
 	}
-	mmdrop(mm);
+	/*
+	 * Defer the cleanup to an alive cpu. On RT we can neither
+	 * call mmdrop() nor mmdrop_delayed() from here.
+	 */
+	per_cpu(idle_last_mm, smp_processor_id()) = mm;
 }
 
 /*
@@ -6262,6 +6436,7 @@ static void migrate_tasks(struct rq *dea
 			break;
 
 		next = __pick_migrate_task(rq);
+		WARN_ON_ONCE(__migrate_disabled(next));
 
 		/*
 		 * Rules for changing task_struct::cpus_mask are holding
@@ -6490,6 +6665,10 @@ int sched_cpu_dying(unsigned int cpu)
 	update_max_interval();
 	nohz_balance_exit_idle(rq);
 	hrtick_clear(rq);
+	if (per_cpu(idle_last_mm, cpu)) {
+		mmdrop_delayed(per_cpu(idle_last_mm, cpu));
+		per_cpu(idle_last_mm, cpu) = NULL;
+	}
 	return 0;
 }
 #endif
@@ -6721,7 +6900,7 @@ void __init sched_init(void)
 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
 static inline int preempt_count_equals(int preempt_offset)
 {
-	int nested = preempt_count() + rcu_preempt_depth();
+	int nested = preempt_count() + sched_rcu_preempt_depth();
 
 	return (nested == preempt_offset);
 }
@@ -7947,3 +8126,172 @@ const u32 sched_prio_to_wmult[40] = {
 };
 
 #undef CREATE_TRACE_POINTS
+
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+
+static inline void
+update_nr_migratory(struct task_struct *p, long delta)
+{
+	if (unlikely((p->sched_class == &rt_sched_class ||
+		      p->sched_class == &dl_sched_class) &&
+		      p->nr_cpus_allowed > 1)) {
+		if (p->sched_class == &rt_sched_class)
+			task_rq(p)->rt.rt_nr_migratory += delta;
+		else
+			task_rq(p)->dl.dl_nr_migratory += delta;
+	}
+}
+
+static inline void
+migrate_disable_update_cpus_allowed(struct task_struct *p)
+{
+	p->cpus_ptr = cpumask_of(smp_processor_id());
+	update_nr_migratory(p, -1);
+	p->nr_cpus_allowed = 1;
+}
+
+static inline void
+migrate_enable_update_cpus_allowed(struct task_struct *p)
+{
+	struct rq *rq;
+	struct rq_flags rf;
+
+	rq = task_rq_lock(p, &rf);
+	p->cpus_ptr = &p->cpus_mask;
+	p->nr_cpus_allowed = cpumask_weight(&p->cpus_mask);
+	update_nr_migratory(p, 1);
+	task_rq_unlock(rq, p, &rf);
+}
+
+void migrate_disable(void)
+{
+	preempt_disable();
+
+	if (++current->migrate_disable == 1) {
+		this_rq()->nr_pinned++;
+		preempt_lazy_disable();
+#ifdef CONFIG_SCHED_DEBUG
+		WARN_ON_ONCE(current->pinned_on_cpu >= 0);
+		current->pinned_on_cpu = smp_processor_id();
+#endif
+	}
+
+	preempt_enable();
+}
+EXPORT_SYMBOL(migrate_disable);
+
+static void migrate_disabled_sched(struct task_struct *p)
+{
+	if (p->migrate_disable_scheduled)
+		return;
+
+	migrate_disable_update_cpus_allowed(p);
+	p->migrate_disable_scheduled = 1;
+}
+
+static DEFINE_PER_CPU(struct cpu_stop_work, migrate_work);
+static DEFINE_PER_CPU(struct migration_arg, migrate_arg);
+
+void migrate_enable(void)
+{
+	struct task_struct *p = current;
+	struct rq *rq = this_rq();
+	int cpu = task_cpu(p);
+
+	WARN_ON_ONCE(p->migrate_disable <= 0);
+	if (p->migrate_disable > 1) {
+		p->migrate_disable--;
+		return;
+	}
+
+	preempt_disable();
+
+#ifdef CONFIG_SCHED_DEBUG
+	WARN_ON_ONCE(current->pinned_on_cpu != cpu);
+	current->pinned_on_cpu = -1;
+#endif
+
+	WARN_ON_ONCE(rq->nr_pinned < 1);
+
+	p->migrate_disable = 0;
+	rq->nr_pinned--;
+#ifdef CONFIG_HOTPLUG_CPU
+	if (rq->nr_pinned == 0 && unlikely(!cpu_active(cpu)) &&
+	    takedown_cpu_task)
+		wake_up_process(takedown_cpu_task);
+#endif
+
+	if (!p->migrate_disable_scheduled)
+		goto out;
+
+	p->migrate_disable_scheduled = 0;
+
+	migrate_enable_update_cpus_allowed(p);
+
+	WARN_ON(smp_processor_id() != cpu);
+	if (!is_cpu_allowed(p, cpu)) {
+		struct migration_arg __percpu *arg;
+		struct cpu_stop_work __percpu *work;
+		struct rq_flags rf;
+
+		work = this_cpu_ptr(&migrate_work);
+		arg = this_cpu_ptr(&migrate_arg);
+		WARN_ON_ONCE(!arg->done && !work->disabled && work->arg);
+
+		arg->task = p;
+		arg->done = false;
+
+		rq = task_rq_lock(p, &rf);
+		update_rq_clock(rq);
+		arg->dest_cpu = select_fallback_rq(cpu, p);
+		task_rq_unlock(rq, p, &rf);
+
+		stop_one_cpu_nowait(task_cpu(p), migration_cpu_stop,
+				    arg, work);
+	}
+
+out:
+	preempt_lazy_enable();
+	preempt_enable();
+}
+EXPORT_SYMBOL(migrate_enable);
+
+int cpu_nr_pinned(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	return rq->nr_pinned;
+}
+
+#elif !defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+static void migrate_disabled_sched(struct task_struct *p)
+{
+}
+
+void migrate_disable(void)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	current->migrate_disable++;
+#endif
+	barrier();
+}
+EXPORT_SYMBOL(migrate_disable);
+
+void migrate_enable(void)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	struct task_struct *p = current;
+
+	WARN_ON_ONCE(p->migrate_disable <= 0);
+	p->migrate_disable--;
+#endif
+	barrier();
+}
+EXPORT_SYMBOL(migrate_enable);
+
+#else
+static void migrate_disabled_sched(struct task_struct *p)
+{
+}
+
+#endif
Index: linux-5.4.5-rt3/kernel/sched/debug.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/debug.c
+++ linux-5.4.5-rt3/kernel/sched/debug.c
@@ -958,6 +958,10 @@ void proc_sched_show_task(struct task_st
 		P(dl.runtime);
 		P(dl.deadline);
 	}
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+	P(migrate_disable);
+#endif
+	P(nr_cpus_allowed);
 #undef PN_SCHEDSTAT
 #undef PN
 #undef __PN
Index: linux-5.4.5-rt3/kernel/sched/fair.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/fair.c
+++ linux-5.4.5-rt3/kernel/sched/fair.c
@@ -4123,7 +4123,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq
 	ideal_runtime = sched_slice(cfs_rq, curr);
 	delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
 	if (delta_exec > ideal_runtime) {
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 		/*
 		 * The current task ran long enough, ensure it doesn't get
 		 * re-elected due to buddy favours.
@@ -4147,7 +4147,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq
 		return;
 
 	if (delta > ideal_runtime)
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 }
 
 static void
@@ -4290,7 +4290,7 @@ entity_tick(struct cfs_rq *cfs_rq, struc
 	 * validating it and just reschedule.
 	 */
 	if (queued) {
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 		return;
 	}
 	/*
@@ -4415,7 +4415,7 @@ static void __account_cfs_rq_runtime(str
 	 * hierarchy can be throttled
 	 */
 	if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
-		resched_curr(rq_of(cfs_rq));
+		resched_curr_lazy(rq_of(cfs_rq));
 }
 
 static __always_inline
@@ -5128,7 +5128,7 @@ static void hrtick_start_fair(struct rq
 
 		if (delta < 0) {
 			if (rq->curr == p)
-				resched_curr(rq);
+				resched_curr_lazy(rq);
 			return;
 		}
 		hrtick_start(rq, delta);
@@ -6730,7 +6730,7 @@ static void check_preempt_wakeup(struct
 	return;
 
 preempt:
-	resched_curr(rq);
+	resched_curr_lazy(rq);
 	/*
 	 * Only set the backward buddy when the current task is still
 	 * on the rq. This can happen when a wakeup gets interleaved
@@ -9997,7 +9997,7 @@ static void task_fork_fair(struct task_s
 		 * 'current' within the tree based on its new key value.
 		 */
 		swap(curr->vruntime, se->vruntime);
-		resched_curr(rq);
+		resched_curr_lazy(rq);
 	}
 
 	se->vruntime -= cfs_rq->min_vruntime;
@@ -10021,7 +10021,7 @@ prio_changed_fair(struct rq *rq, struct
 	 */
 	if (rq->curr == p) {
 		if (p->prio > oldprio)
-			resched_curr(rq);
+			resched_curr_lazy(rq);
 	} else
 		check_preempt_curr(rq, p, 0);
 }
Index: linux-5.4.5-rt3/kernel/sched/features.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/features.h
+++ linux-5.4.5-rt3/kernel/sched/features.h
@@ -45,11 +45,19 @@ SCHED_FEAT(DOUBLE_TICK, false)
  */
 SCHED_FEAT(NONTASK_CAPACITY, true)
 
+#ifdef CONFIG_PREEMPT_RT
+SCHED_FEAT(TTWU_QUEUE, false)
+# ifdef CONFIG_PREEMPT_LAZY
+SCHED_FEAT(PREEMPT_LAZY, true)
+# endif
+#else
+
 /*
  * Queue remote wakeups on the target CPU and process them
  * using the scheduler IPI. Reduces rq->lock contention/bounces.
  */
 SCHED_FEAT(TTWU_QUEUE, true)
+#endif
 
 /*
  * When doing wakeups, attempt to limit superfluous scans of the LLC domain.
Index: linux-5.4.5-rt3/kernel/sched/isolation.c
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/isolation.c
+++ linux-5.4.5-rt3/kernel/sched/isolation.c
@@ -8,6 +8,7 @@
  *
  */
 #include "sched.h"
+#include "../../mm/internal.h"
 
 DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
 EXPORT_SYMBOL_GPL(housekeeping_overridden);
@@ -139,10 +140,21 @@ static int __init housekeeping_setup(cha
 static int __init housekeeping_nohz_full_setup(char *str)
 {
 	unsigned int flags;
+	int ret;
 
 	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC;
 
-	return housekeeping_setup(str, flags);
+	ret = housekeeping_setup(str, flags);
+
+	/*
+	 * Protect struct pagevec with a lock instead using preemption disable;
+	 * with lock protection, remote handling of events instead of queue
+	 * work on remote cpu is default behavior.
+	 */
+	if (ret)
+		static_branch_enable(&use_pvec_lock);
+
+	return ret;
 }
 __setup("nohz_full=", housekeeping_nohz_full_setup);
 
Index: linux-5.4.5-rt3/kernel/sched/sched.h
===================================================================
--- linux-5.4.5-rt3.orig/kernel/sched/sched.h
+++ linux-5.4.5-rt3/kernel/sched/sched.h
@@ -999,6 +999,10 @@ struct rq {
 	/* Must be inspected within a rcu lock section */
 	struct cpuidle_state	*idle_state;
 #endif
+
+#if defined(CONFIG_PREEMPT_RT) && defined(CONFIG_SMP)
+	int			nr_pinned;
+#endif
 };
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
@@ -1644,6 +1648,7 @@ static inline int task_on_rq_migrating(s
 #def