Re: [PATCH 2/4] Revert "x86/boot: Fail the boot if !M486 and CPUID is missing"

From: Thomas Gleixner
Date: Thu Dec 01 2016 - 05:11:10 EST


On Thu, 1 Dec 2016, Borislav Petkov wrote:
> On Thu, Dec 01, 2016 at 06:53:50AM +0100, Peter Zijlstra wrote:
> > On Wed, Nov 30, 2016 at 12:34:53PM -0800, Andy Lutomirski wrote:
> > > This reverts commit ed68d7e9b9cfb64f3045ffbcb108df03c09a0f98.
> > >
> > > The patch wasn't quite correct -- there are non-Intel (and hence
> > > non-486) CPUs that we support that don't have CPUID. Since we no
> > > longer require CPUID for sync_core(), just revert the patch.
> >
> > Might be useful to enumerate which special parts these are.
>
> Right, and since we test for CPUID support at early boot, I think we
> should use the X86_FEATURE_CPUID aspect from what I proposed earlier:
>
> https://lkml.kernel.org/r/20161120111917.pw3alolx4fksfwbv@xxxxxxx

Yes, that makes a lot of sense.

Thanks,

tglx