Messages in this thread | | | Date | Fri, 20 Jun 2014 09:37:57 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [RFC][PATCH 3/3] x86: make MP a required-feature on 64-bit |
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On 06/20/2014 09:30 AM, Dave Hansen wrote: > On 06/20/2014 09:23 AM, H. Peter Anvin wrote: >> On 06/20/2014 09:17 AM, Dave Hansen wrote: >>>> Today, we assume that all 64-bit cpus have X86_FEATURE_MP. It >>>> should be in the REQUIRED_MASK so that we do not need the #undef >>>> trick for it. >> I don't think we enforce that the MP bit is set in CPUID, though. >> Non-AMD processors will typically not set this bit at all, so the >> feature validation code would have to be modified to know to not require >> this bit. > > Ahh, OK. I'll drop this. >
We probably should just the cpu_has_mp macro entirely. All it is used for is printing a warning in amd_k7_smp_check().
Andi, Borislav -- as far as I can tell, we have *never* enforced this on the 64-bit kernel, although we have enforced it on 64-bit processors running the 32-bit kernel. We should either enforce it on both or just drop it. What is your opinion?
-hpa
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