On Sat Nov 19, 2022 at 1:07 AM AEST, Nathan Lynch wrote: > 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 <nath...@linux.ibm.com> > --- > 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. > + */
We can call this in real-mode via pseries_machine_check_realmode -> fwnmi_release_errinfo, so tracing should be disabled for that case too... Does this_cpu_set_ftrace_enabled(0) in the early machine check handler cover that sufficiently? Thanks, Nick