[RFC][PATCH] ppc: Implement save_stack_trace_regs()

[Michael Ellerman]

On Tue, 2015-12-08 at 13:50 -0500, Steven Rostedt wrote:

> It has come to my attention that kprobe event stack tracing does not
> work on powerpc.

Yep looks like you're right. I didn't realise it was separate from the regular
stack trace stuff.

> diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c
> index ea43a347a104..0142c86801ba 100644
> --- a/arch/powerpc/kernel/stacktrace.c
> +++ b/arch/powerpc/kernel/stacktrace.c
> @@ -61,3 +61,10 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
>  	save_context_stack(trace, tsk->thread.ksp, tsk, 0);
>  }
>  EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
> +
> +void
> +save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
> +{
> +	save_context_stack(trace, regs->gpr[PT_R1], current, 0);

In the kernel we would normally use just '1' here rather than 'PT_R1', but it's
not a huge deal.

Should I take this via powerpc or do you want it to go in via tracing?

cheers