Messages in this thread | | | Date | Thu, 29 Nov 2012 13:06:20 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 8/8] x86, cleanups: Simplify sync_core() in the case of no CPUID |
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On 11/29/2012 01:13 AM, Borislav Petkov wrote: > > RCX gets correctly cleaned to 0 and *then* we call CPUID. > > And the asm output is the same except that RCX gets correctly cleaned up > before calling CPUID. > > So what am I missing? >
It doesn't matter in that context, as the surrounding MSR references have barriers, but what I'm refering to is the "memory" barrier.
The value of ECX doesn't matter when EAX=1.
-hpa
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