Re: [PATCH 1/6] x86: Add support for the pcommit instruction

Andy Lutomirski
2014-11-13T03:25:42Z

On 11/11/2014 10:43 AM, Ross Zwisler wrote:
> Add support for the new pcommit instruction. This instruction was
> announced in the document "Intel Architecture Instruction Set Extensions
> Programming Reference" with reference number 319433-022.
>
> https://software.intel.com/sites/default/files/managed/0d/53/319433-022.pdf
>
> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> Cc: H Peter Anvin <h.peter.anvin@intel.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: David Airlie <airlied@linux.ie>
> Cc: dri-devel@lists.freedesktop.org
> Cc: x86@kernel.org
> ---
> arch/x86/include/asm/cpufeature.h | 1 +
> arch/x86/include/asm/special_insns.h | 6 ++++++
> 2 files changed, 7 insertions(+)
>
> diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
> index 0bb1335..b3e6b89 100644
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -225,6 +225,7 @@
> #define X86_FEATURE_RDSEED ( 9*32+18) /* The RDSEED instruction */
> #define X86_FEATURE_ADX ( 9*32+19) /* The ADCX and ADOX instructions */
> #define X86_FEATURE_SMAP ( 9*32+20) /* Supervisor Mode Access Prevention */
> +#define X86_FEATURE_PCOMMIT ( 9*32+22) /* PCOMMIT instruction */
> #define X86_FEATURE_CLFLUSHOPT ( 9*32+23) /* CLFLUSHOPT instruction */
> #define X86_FEATURE_AVX512PF ( 9*32+26) /* AVX-512 Prefetch */
> #define X86_FEATURE_AVX512ER ( 9*32+27) /* AVX-512 Exponential and Reciprocal */
> diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
> index e820c08..1709a2e 100644
> --- a/arch/x86/include/asm/special_insns.h
> +++ b/arch/x86/include/asm/special_insns.h
> @@ -199,6 +199,12 @@ static inline void clflushopt(volatile void *__p)
> "+m" (*(volatile char __force *)__p));
> }
>
> +static inline void pcommit(void)
> +{
> + alternative(ASM_NOP4, ".byte 0x66, 0x0f, 0xae, 0xf8",
> + X86_FEATURE_PCOMMIT);
> +}
> +

Should this patch add the feature bit and cpuinfo entry to go with it?

--Andy