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

[Jamie Lokier]

Bill Davidsen wrote:
> > prefetch isn't a cpuid feature flag. The only way you could do
> > what you suggest is by removing '3dnow' or 'sse', which cripples
> > things more than necessary.
> 
> Good point, and even if it were a separate feature, any code which was
> clever enough to use prefetch is likely to check the CPU bits rather
> than the /proc anyway. That's a guess, I suspect most programs do
> whatever gcc/glibc choose.

As I pointed out, other programs _especially_ glibc will need to check
for the AMD errata anyway, because of older kernels.

> If the fixup were not in place, would it be useful to emit a warning
> like "you have booted a non-Athlon kernel on an Athlon process, user
> programs may get unexpected page faults."

I agree, that's a good idea.  It will fit nicely alongside the
messages for broken WP bit etc.

-- Jamie
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