Re: [PATCH v2] x86/cpufeatures: Enable new SSE/AVX/AVX512 cpu features

From: Borislav Petkov
Date: Tue Oct 31 2017 - 16:02:56 EST


On Tue, Oct 31, 2017 at 07:37:29PM +0000, Yu, Fenghua wrote:
> Should we change the legacy names as well? User apps may use the names
> already. Changing the names may break the apps.

Yeah, we can't do that.

> If we do make all uniform, do you prefer adding "_" after AVX512?

Well, I think we can forget the whole endeavor. We already have the two
variants, which we can't change anymore:

#define X86_FEATURE_AVX512_4VNNIW (7*32+16) /* AVX-512 Neural Network Instructions */
#define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
#define X86_FEATURE_AVX512F ( 9*32+16) /* AVX-512 Foundation */
#define X86_FEATURE_AVX512DQ ( 9*32+17) /* AVX-512 DQ (Double/Quad granular) Instructions */
#define X86_FEATURE_AVX512IFMA ( 9*32+21) /* AVX-512 Integer Fused Multiply-Add instructions */
#define X86_FEATURE_AVX512PF ( 9*32+26) /* AVX-512 Prefetch */
#define X86_FEATURE_AVX512ER ( 9*32+27) /* AVX-512 Exponential and Reciprocal */
#define X86_FEATURE_AVX512CD ( 9*32+28) /* AVX-512 Conflict Detection */
#define X86_FEATURE_AVX512BW ( 9*32+30) /* AVX-512 BW (Byte/Word granular) Instructions */
#define X86_FEATURE_AVX512VL ( 9*32+31) /* AVX-512 VL (128/256 Vector Length) Extensions */
#define X86_FEATURE_AVX512VBMI (16*32+ 1) /* AVX512 Vector Bit Manipulation instructions*/
#define X86_FEATURE_AVX512_VPOPCNTDQ (16*32+14) /* POPCNT for vectors of DW/QW */

:-\

Oh well, as long as the AVX512 prefix is there at least the grepping works.

--
Regards/Gruss,
Boris.

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