Re: [RFC][PATCH v3] ftrace/x86_64: Emulate call function while updating in breakpoint handler

[Peter Zijlstra]

On Wed, May 01, 2019 at 11:01:07AM -0700, Linus Torvalds wrote:
> This looks sane to me, although I'm surprised that we didn't already
> have an annotation for the nonstandard stack frame for asm files. That
> probably would be cleaner in a separate commit, but I guess it doesn't
> matter.
> 
> Anyway, I'm willing to consider the entry code version if it looks a
> _lot_ simpler than this (so I'd like to see them side-by-side), but
> it's not like this looks all that complicated to me either.

So I posted one earlier today:

  https://lkml.kernel.org/r/20190501131117.GW2623@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

it's about a 1/3rd the number of lines and has 32bit support. It also
provides all the bits required to implement static_call().

That is; I think I'm firmly in favour of the entry variant -- provided
it actually works of course.