Re: [PATCH] 2.6 workaround for Athlon/Opteron prefetch errata

Adrian Bunk
2003-09-12T18:51:14Z

On Fri, Sep 12, 2003 at 08:28:51PM +0200, Andi Kleen wrote:
> On Fri, 12 Sep 2003 20:22:16 +0200
> Adrian Bunk <bunk@fs.tum.de> wrote:
>
>
> >
> > But even CONFIG_X86_GENERIC doesn't do what you expect. A kernel
> > compiled for Athlon wouldn't run on a Pentium 4 even with
> > CONFIG_X86_GENERIC.
>
> It does. Just try it.
>
> >
> > Quoting arch/i386/Kconfig in -test5:
> >
> > <-- snip -->
> >
> > config X86_USE_3DNOW
> > bool
> > depends on MCYRIXIII || MK7
> > default y
>
> That's obsolete and could be removed. All 3dnow! code is dynamically patched depending on the CPUID.

Quoting e.g. arch/i386/lib/memcpy.c:

<-- snip -->

void * memcpy(void * to, const void * from, size_t n)
{
#ifdef CONFIG_X86_USE_3DNOW
return __memcpy3d(to, from, n);
#else
return __memcpy(to, from, n);
#endif
}

<-- snip -->

This is hardly dynamic.

> -Andi

cu
Adrian

--

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"Only a promise," Lao Er said.
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