Re: [RFC PATCH] ftrace/x86: Move the mcount/fentry code out of entry_64.S

From: Thomas Gleixner
Date: Thu May 08 2014 - 18:21:29 EST


On Thu, 8 May 2014, Steven Rostedt wrote:

>
> As the mcount code gets more complex, it really does not belong
> in the entry.S file. By moving it into its own file "mcount.S"
> keeps things a bit cleaner.
>
> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> ---
>
> Note:
> With changes to the ftrace infrastructure to help with the current
> influx of live patching facilities that we are seeing, I'm going to
> have to make new changes to mcount trampolines. Currently they live in
> entry*.S. They were only placed there for convenience, but not because
> that was the proper place to place it. As other architectures have a
> separate mcount.S file, I think it would be prudent to have x86 do the
> same. Especially as the trampoline code may start to expand for the
> live patching work. Currently, only x86_64 is converted, but there's no
> reason that i386 can't have it as well.
>
> Thoughts?

I'm fine with the code move per se. That's a good thing.

The live patcher argumentation for it is more than questionable.

Thanks,

tglx
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