Re: [PATCH v4 02/14] x86/cpufeatures: add AMD Fam19h Branch Sampling feature

From: Borislav Petkov
Date: Fri Dec 10 2021 - 16:21:39 EST


On Fri, Dec 10, 2021 at 01:02:17PM -0800, Stephane Eranian wrote:
> This patch adds a cpu feature for AMD Fam19h Branch Sampling feature as bit
> 31 of EBX on CPUID leaf function 0x80000008.
>
> Signed-off-by: Stephane Eranian <eranian@xxxxxxxxxx>
> ---
> arch/x86/include/asm/cpufeatures.h | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index d5b5f2ab87a0..e71443f93f04 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -315,6 +315,7 @@
> #define X86_FEATURE_AMD_SSBD (13*32+24) /* "" Speculative Store Bypass Disable */
> #define X86_FEATURE_VIRT_SSBD (13*32+25) /* Virtualized Speculative Store Bypass Disable */
> #define X86_FEATURE_AMD_SSB_NO (13*32+26) /* "" Speculative Store Bypass is fixed in hardware. */
> +#define X86_FEATURE_AMD_BRS (13*32+31) /* Branch Sampling available */
>
> /* Thermal and Power Management Leaf, CPUID level 0x00000006 (EAX), word 14 */
> #define X86_FEATURE_DTHERM (14*32+ 0) /* Digital Thermal Sensor */
> --

It seems you missed my note from the last time:

https://lore.kernel.org/r/YY0OUNqv1w/ihmHX@xxxxxxx

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette