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

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Message-ID: <YbPE3PDQ6Ro9oVEH@zn.tnic>
Date:   Fri, 10 Dec 2021 22:21:32 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Stephane Eranian <eranian@...gle.com>
Cc:     linux-kernel@...r.kernel.org, peterz@...radead.org,
        kim.phillips@....com, acme@...hat.com, jolsa@...hat.com,
        songliubraving@...com, mpe@...erman.id.au, maddy@...ux.ibm.com
Subject: Re: [PATCH v4 02/14] x86/cpufeatures: add AMD Fam19h Branch Sampling
 feature

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@...gle.com>
> ---
>  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@zn.tnic

-- 
Regards/Gruss,
    Boris.

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