Re: [git pull] x86 fixes

[Mark Lord]

Mark Lord wrote:
> Andi Kleen wrote:
> > Krzysztof Halasa <khc@xxxxxxxxx> writes:
> >
> > > Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> writes:
> > >
> > > >  - "modern 32-bit": PPro and better. Can take CMOV, MMX and TSC for 
> > > >    granted.
> > > VIA C3 (Samuel 2/Ezra, 600 - 1000 MHz?, common on VIA EPIA-*: home
> > > theatres etc) can't CMOV.
> >
> > AFAIK they fixed that in newer BIOS with a microcode update. It's 
> > slow, but it works.
> ..
>
> Our firewall here uses a Via C3-600 CPU, and CMOV has never worked on it.
> But based upon your posting, I have today upgraded the BIOS to the
> latest (2004) version.
>
> Now.. how can I check whether CMOV works or not?  It's not listed in 
> /proc/cpuinfo.
..

H. Peter Anvin wrote:
> Compile just about any C program with -march=i686.
..

Okay, done.  And the binary does indeed have a ton of CMOV instructions.
When running it, this appears immediately:

   Illegal instruction

So much for the "BIOS upgrade fixes CMOV microcode" theory.

Cheers
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