Call the just-added rtas tracepoints in do_enter_rtas(), taking care
to avoid function name lookups in the CPU offline path.

Signed-off-by: Nathan Lynch <redacted>
---
 arch/powerpc/kernel/rtas.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 198366d641d0..3487b42cfbf7 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c

@@ -38,6 +38,7 @@
 #include <asm/page.h>
 #include <asm/rtas.h>
 #include <asm/time.h>
+#include <asm/trace.h>
 #include <asm/udbg.h>
 
 enum rtas_function_flags {

@@ -525,6 +526,7 @@ void enter_rtas(unsigned long);
 static void do_enter_rtas(struct rtas_args *args)
 {
 	unsigned long msr;
+	const char *name = NULL;
 
 	/*
 	 * Make sure MSR[RI] is currently enabled as it will be forced later

@@ -537,9 +539,30 @@ static void do_enter_rtas(struct rtas_args *args)
 
 	hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
 
+	if ((trace_rtas_input_enabled() || trace_rtas_output_enabled())) {
+		/*
+		 * rtas_token_to_function() uses xarray which uses RCU,
+		 * but this code can run in the CPU offline path
+		 * (e.g. stop-self), after it's become invalid to call
+		 * RCU APIs.
+		 */