Re: [PATCH] x86/nospec: Unwreck the RSB stuffing

From: Peter Zijlstra
Date: Wed Aug 17 2022 - 02:55:34 EST


On Tue, Aug 16, 2022 at 11:04:36AM -0700, Daniel Sneddon wrote:
> diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
> index 1a31ae6d758b..c5b55c9f2849 100644
> --- a/arch/x86/include/asm/cpufeatures.h
> +++ b/arch/x86/include/asm/cpufeatures.h
> @@ -420,7 +420,7 @@
> #define X86_FEATURE_V_TSC_AUX (19*32+ 9) /* "" Virtual TSC_AUX */
> #define X86_FEATURE_SME_COHERENT (19*32+10) /* "" AMD hardware-enforced
> cache coherency */
>
> -#define X86_FEATURE_NEVER (-1) /* "" Logical complement of ALWAYS */
> +#define X86_FEATURE_NEVER (0x7FFF) /* "" Logical complement of
> ALWAYS */


Bah, I initially spelled that: ALT_NOT(X86_FEATURE_ALWAYS), but Boris
made me do the -1 thing there. Oh well, Boris can fix that :-)