Re: [PATCH v2 2/4] x86/cpufeatures: Enumerate TSX suspend load address tracking instructions

From: Greg KH
Date: Tue Jul 07 2020 - 05:40:25 EST


On Tue, Jul 07, 2020 at 10:16:21AM +0800, Cathy Zhang wrote:
> Intel TSX suspend load tracking instructions aim to give a way to
> choose which memory accesses do not need to be tracked in the TSX
> read set. Add TSX suspend load tracking CPUID feature flag TSXLDTRK
> for enumeration.
>
> A processor supports Intel TSX suspend load address tracking if
> CPUID.0x07.0x0:EDX[16] is present. Two instructions XSUSLDTRK, XRESLDTRK
> are available when this feature is present.
>
> The CPU feature flag is shown as "tsxldtrk" in /proc/cpuinfo.
>
> Detailed information on the instructions and CPUID feature flag TSXLDTRK
> can be found in the latest Intel Architecture Instruction Set Extensions
> and Future Features Programming Reference and Intel 64 and IA-32
> Architectures Software Developer's Manual.
>
> Signed-off-by: Kyung Min Park <kyung.min.park@xxxxxxxxx>
> Signed-off-by: Cathy Zhang <cathy.zhang@xxxxxxxxx>
> ---
> 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 adf45cf..34b66d7 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -366,6 +366,7 @@
> #define X86_FEATURE_MD_CLEAR (18*32+10) /* VERW clears CPU buffers */
> #define X86_FEATURE_TSX_FORCE_ABORT (18*32+13) /* "" TSX_FORCE_ABORT */
> #define X86_FEATURE_SERIALIZE (18*32+14) /* SERIALIZE instruction */
> +#define X86_FEATURE_TSX_LDTRK (18*32+16) /* TSX Suspend Load Address Tracking */

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