Messages in this thread | | | Date | Wed, 15 Jan 2003 12:18:15 +0000 | From | Dave Jones <> | Subject | Re: new CPUID bit |
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On Wed, Jan 15, 2003 at 09:34:28AM +0100, Mikael Pettersson wrote:
> A better reference for this stuff is (IMHO) AP-485, the "Intel Processor > Identification and the CPUID Instruction" application note. It's regularly > updated, and in this particular case, its description of CPUID with EAX=1 > differs from the IA32 Volume 2 manual (245471xx) in two ways: > > - EBX bit 31 is called "SBF", Signal Break on FERR. > - ECX is defined to contain additional feature flags. Currently only one > is defined: ECX bit 10 is the "Context ID" feature for putting the L1 > D-cache in adaptive or shared mode, which matters for hyper-threaded CPUs. > > Supporting the new ECX feature flags in the kernel will require some surgery, > since the current code assumes x86_capability[0] is Intel, [1] is AMD, > [2] is Transmeta, and [3] is for conflicting or synthesized feature flags. > We either shift AMD etc down one index and put ECX in [1], or add a new index > [4] for ECX, or kludge the few ECX-defined features in [3].
Or we change it so we end up with something like..
x86_capability[0].standard and x86_capability[0].extended
Dave
-- | Dave Jones. http://www.codemonkey.org.uk | SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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