RE: [PATCH] Mutilated form of Andi Kleen's AMD prefetch errata patch

Nakajima, Jun
2003-10-01T01:54:15Z

> I think we should fix up userspace.
What do you mean by this? Patch user code at runtime (it's much more
complex than it sounds) or remove prefetch instructions from userspace?

Jun

> -----Original Message-----
> From: linux-kernel-owner@vger.kernel.org [mailto:linux-kernel-
> owner@vger.kernel.org] On Behalf Of Andrew Morton
> Sent: Tuesday, September 30, 2003 5:27 PM
> To: Jamie Lokier
> Cc: davej@redhat.com; torvalds@osdl.org; linux-kernel@vger.kernel.org;
> richard.brunner@amd.com
> Subject: Re: [PATCH] Mutilated form of Andi Kleen's AMD prefetch
errata
> patch
>
> Jamie Lokier <jamie@shareable.org> wrote:
> >
> > What I'd really like your opinion on is the appropriate userspace
> > behaviour. If we don't care about fixing up userspace, then
> > __ex_table is a much tidier workaround for the prefetch bug.
>
> I think we should fix up userspace.
>
> > If we do
> > care about fixing up userspace, then do we need a policy decision
that
> > says it's not acceptable to run on AMD without userspace fixups from
> > 2.6.0 onwards - it must fixup userspace or refuse to run?
>
> If you're saying that the kernel should refuse to boot if it discovers
> that
> a) the CPU needs the workaround and b) the kernel does not implement
the
> workaround then yup.
>
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