Re: [PATCH 1/2 v3] x86: introduce int3-based instruction patching

From: Jiri Kosina
Date: Thu Jul 11 2013 - 18:31:59 EST


On Thu, 11 Jul 2013, H. Peter Anvin wrote:

> > synchronization after replacing "all but first" instructions should not
> > be necessary (on Intel hardware), as the syncing after the subsequent
> > patching of the first byte provides enough safety.
> > But there's not only Intel HW out there, and we'd rather be on a safe
> > side.
>
> Has anyone talked to AMD or VIA about this at all? Did anyone else ever
> make SMP-capable x86?

If Boris can verify for AMD, that'd be good; we could then just remove one
extra syncing of the cores as a followup (can be done any time later, both
for alternative.c and ftrace in fact).

With the "extra" sync, the procedure is already verified to work properly
by ftace.

Thanks,

--
Jiri Kosina
SUSE Labs
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