Re: [PATCH v1]: perf/x86: store user space frame-pointer value on a sample

[Andi Kleen]

> diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c
> index e47b2dbbdef3..9284048cf5b0 100644
> --- a/arch/x86/kernel/perf_regs.c
> +++ b/arch/x86/kernel/perf_regs.c
> @@ -157,6 +157,15 @@ void perf_get_regs_user(struct perf_regs *regs_user,
>  	 */
>  	regs_user_copy->bx = -1;
>  	regs_user_copy->bp = -1;
> +	if (user_64bit_mode(user_regs)) {

Why is it 64bit only? Should work on 32bit too.

-Andi

> +		/*
> +		 * Store user space frame-pointer value on sample
> +		 * to facilitate stack unwinding for cases when
> +		 * user space x86_64 executable code has such
> +		 * support enabled at compile time;
> +		 */
> +		regs_user_copy->bp = user_regs->bp;
> +	}
>  	regs_user_copy->r12 = -1;
>  	regs_user_copy->r13 = -1;
>  	regs_user_copy->r14 = -1;