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
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20250108090457.512198-21-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

diff --git a/arch/powerpc/kernel/trace/ftrace.c b/arch/powerpc/kernel/trace/ftrace.c
index 2f776f137a89ecfe83f060e62c689ed46ee6b56f..6dca92d5a6e82208ffc8e0e8ef851681e37c3801 100644 (file)
--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -115,10 +115,8 @@ static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long a
 {
        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);
 

diff --git a/arch/powerpc/kernel/trace/ftrace_64_pg.c b/arch/powerpc/kernel/trace/ftrace_64_pg.c
index ac35015f04c6ad2dd3eaeab88c20bc0a8d4a3663..5c6e545d1708ca9da33ee9825a18dab9189461a4 100644 (file)
--- a/arch/powerpc/kernel/trace/ftrace_64_pg.c
+++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c
@@ -120,10 +120,8 @@ static struct module *ftrace_lookup_module(struct dyn_ftrace *rec)
 {
        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);