Re: [Fwd: CPU detection revamp (Request for comments)]

From: H. Peter Anvin (hpa@transmeta.com)
Date: Fri Nov 10 2000 - 14:55:03 EST


davej@suse.de wrote:

> On Fri, 10 Nov 2000, Brian Gerst wrote:
>
> > > features : fpu vme de pse tsc msr mce cx8 pge mmx syscall 3dnow
> >
> > The K6's don't support sysenter/sysexit.
>
> The K6 datasheets suggests otherwise.
> Some models seem to have sysenter/sysexit, whilst others have
> syscall/sysret. No model seems to have both.

Athlons have both. Since the ext-bit 10 stuff is useless, I haven't
bothered reporting it at all.

> The datasheets are somewhat confusing, as it doesn't mention bit 10
> at all, just an oversized box for bit 11.
>
> > It really should have been marked differently before.
>
> Before we weren't mentioning it at all, look..
> flags : fpu vme de pse tsc msr mce cx8 sep mtrr pge mmx 3dnow
>
> > The early K6's used extended bit 10 to indicate syscall/sysret
> > capabality, but this version has some quirks that make it pretty much
> > unusable. Later K6's use extended bit 11 to indicate syscall/sysret.
>
> And where does sysenter/sysexit fit in?

sysenter/sysexit is the "sep" feature.

        -hpa

-- 
<hpa@transmeta.com> at work, <hpa@zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."
http://www.zytor.com/~hpa/puzzle.txt
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