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x86/cpu/vfm: Add/initialize x86_vfm field to struct cpuinfo_x86

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Refactor struct cpuinfo_x86 so that the vendor, family, and model
fields are overlaid 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.

See

  https://lore.kernel.org/r/Zgr6kT8oULbnmEXx@agluck-desk3

for why the ordering is (low-to-high bits):

  (vendor, family, model)

  [ bp: Move comments over the line, add the backstory about the
    particular order of the fields. ]

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240416211941.9369-2-tony.luck@intel.com
This commit is contained in:
Tony Luck 2024-04-16 14:19:03 -07:00 committed by Borislav Petkov (AMD)
parent 90167e9658
commit a9d0adce69
1 changed files with 17 additions and 3 deletions
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20
arch/x86/include/asm/processor.h
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@ -108,9 +108,23 @@ struct cpuinfo_topology {
};
struct cpuinfo_x86 {
__u8 x86; /* CPU family */
__u8 x86_vendor; /* CPU vendor */
__u8 x86_model;
union {
/*
* The particular ordering (low-to-high) of (vendor,
* family, model) is done in case range of models, like
* it is usually done on AMD, need to be compared.
*/
struct {
__u8 x86_model;
/* CPU family */
__u8 x86;
/* CPU vendor */
__u8 x86_vendor;
__u8 x86_reserved;
};
/* combined vendor, family, model */
__u32 x86_vfm;
};
__u8 x86_stepping;
#ifdef CONFIG_X86_64
/* Number of 4K pages in DTLB/ITLB combined(in pages): */