linux-kernel - Re: [PATCH v2 02/13] x86/cpufeatures: add AMD Fam19h Branch Sampling feature

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 11 Nov 2021 13:36:32 +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 v2 02/13] x86/cpufeatures: add AMD Fam19h Branch Sampling
 feature

On Thu, Nov 11, 2021 at 12:44:04AM -0800, Stephane Eranian wrote:
> This patch adds a cpu feature for AMD Fam19h Branch Sampling feature as bit

For all your commit messages:

s/This patch adds/Add/

"This patch" in a commit message is a tautology.

> 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 */

	X86_FEATURE_BRS

is perfectly fine - there's no need to say "amd_brs" in /proc/cpuinfo on
AMD machines as this is where this flag will be only set.

Thx.

-- 
Regards/Gruss,
    Boris.

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