Re: [GIT PULL] ftrace/x86: Add frames pointers to trampoline as necessary

From: Linus Torvalds
Date: Fri Nov 21 2014 - 20:35:25 EST


On Fri, Nov 21, 2014 at 6:50 AM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> +.macro create_frame parent rip
> +#ifdef CC_USING_FENTRY
> + pushq \parent
> + pushq %rbp
> + movq %rsp, %rbp

This is a very strange frame.

Why do you do the "pushq \parent" at all? Why isn't this just a *real*
frame and add it to MCOUNT_SAVE_FRAME.

You seem to create this fake frame-within-a-frame thing. It's not clear why.

Linus
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