Re: [PATCH v2 4/4] x86/static_call: Add inline static call implementation for x86-64

[Steven Rostedt]

On Thu, 29 Nov 2018 09:35:11 -0800
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, Nov 29, 2018 at 9:13 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> >
> > No, we really do need to sync after we change the second part of the
> > command with the int3 on it. Unless there's another way to guarantee
> > that the full instruction gets seen when we replace the int3 with the
> > finished command.  
> 
> Making sure the call instruction is aligned with the I$ fetch boundary
> should do that.
> 
> It's not in the SDM, but neither was our current behavior - we
> were/are just relying on "it will work".
>

Well, the current method (as Jiri mentioned) did get the OK from at
least Intel (and that was with a lot of arm twisting to do so).

-- Steve