From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Wed, 8 Jan 2025 10:04:49 +0100
Subject: [PATCH 20/28] powerpc/ftrace: Use RCU in all users of
 __module_text_address().

__module_text_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_text_address()
with RCU.

Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-trace-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-21-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 arch/powerpc/kernel/trace/ftrace.c       |    6 ++----
 arch/powerpc/kernel/trace/ftrace_64_pg.c |    6 ++----
 2 files changed, 4 insertions(+), 8 deletions(-)

@ arch/powerpc/kernel/trace/ftrace.c:118 @ static unsigned long ftrace_lookup_modul
 {
 	struct module *mod = NULL;
 
-	preempt_disable();
-	mod = __module_text_address(ip);
-	preempt_enable();
-
+	scoped_guard(rcu)
+		mod = __module_text_address(ip);
 	if (!mod)
 		pr_err("No module loaded at addr=%lx\n", ip);
 
--- a/arch/powerpc/kernel/trace/ftrace_64_pg.c
+++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c
@ arch/powerpc/kernel/trace/ftrace.c:123 @ static struct module *ftrace_lookup_modu
 {
 	struct module *mod;
 
-	preempt_disable();
-	mod = __module_text_address(rec->ip);
-	preempt_enable();
-
+	scoped_guard(rcu)
+		mod = __module_text_address(rec->ip);
 	if (!mod)
 		pr_err("No module loaded at addr=%lx\n", rec->ip);