Messages in this thread | | | Date | Thu, 28 Mar 2024 17:48:11 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 01/74] x86/cpu/vfm: Add/initialize x86_vfm field to struct cpuinfo_x86 |
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On Thu, Mar 28, 2024 at 09:37:44AM -0700, Tony Luck wrote: > Refactor struct cpuinfo_x86 so that the vendor, family, and model > fields are overlayed in a union with a 32-bit field that combines > all three (together with a one byte reserved field in the upper > byte). > > This will make it easy, cheap, and reliable to check all three > values at once. > > Signed-off-by: Tony Luck <tony.luck@intel.com> > --- > arch/x86/include/asm/processor.h | 12 +++++++++--- > 1 file changed, 9 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h > index 811548f131f4..87115e5d884f 100644 > --- a/arch/x86/include/asm/processor.h > +++ b/arch/x86/include/asm/processor.h > @@ -108,9 +108,15 @@ struct cpuinfo_topology { > }; > > struct cpuinfo_x86 { > - __u8 x86; /* CPU family */ > - __u8 x86_vendor; /* CPU vendor */ > - __u8 x86_model; > + union { > + struct { > + __u8 x86_vendor; /* CPU vendor */ > + __u8 x86; /* CPU family */ > + __u8 x86_model; > + __u8 x86_reserved; > + }; > + __u32 x86_vfm; /* combined vendor, family, model */ > + }; > __u8 x86_stepping;
Why are you leaving out stepping?
And since we want to simplify all this, why aren't we replacing all f/m/s checks by using the whole CPUID(1).EAX u32 instead?
Then the macros need to build that CPUID leaf simply.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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