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x86/crc: drop the avx10_256 functions and rename avx10_512 to avx512

Message ID 20250319181316.91271-1-ebiggers@kernel.org (mailing list archive)
State Under Review
Delegated to: Herbert Xu
Headers show
Series x86/crc: drop the avx10_256 functions and rename avx10_512 to avx512 | expand

Commit Message

Eric Biggers March 19, 2025, 6:13 p.m. UTC 
From: Eric Biggers <ebiggers@google.com>

Intel made a late change to the AVX10 specification that removes support
for a 256-bit maximum vector length and enumeration of the maximum
vector length.  AVX10 will imply a maximum vector length of 512 bits.
I.e. there won't be any such thing as AVX10/256 or AVX10/512; there will
just be AVX10, and it will essentially just consolidate AVX512 features.

As a result of this new development, my strategy of providing both
*_avx10_256 and *_avx10_512 functions didn't turn out to be that useful.
The only remaining motivation for the 256-bit AVX512 / AVX10 functions
is to avoid downclocking on older Intel CPUs.  But I already wrote
*_avx2 code too (primarily to support CPUs without AVX512), which
performs almost as well as *_avx10_256.  So we should just use that.

Therefore, remove the *_avx10_256 functions, and rename the *_avx10_512
functions to *_avx512.  Make Ice Lake and Tiger Lake use the *_avx2
functions instead of *_avx10_256 which they previously used.

Signed-off-by: Eric Biggers <ebiggers@google.com>
---
 arch/x86/lib/crc-pclmul-template.S | 23 ++++++++---------------
 arch/x86/lib/crc-pclmul-template.h | 15 +++++----------
 2 files changed, 13 insertions(+), 25 deletions(-)


base-commit: 981b39dc6da6dd11ec40824a224c1e0a7557b5ca
diff mbox series

Patch

diff --git a/arch/x86/lib/crc-pclmul-template.S b/arch/x86/lib/crc-pclmul-template.S
index a19b730b642d3..ae0b6144c503c 100644
--- a/arch/x86/lib/crc-pclmul-template.S
+++ b/arch/x86/lib/crc-pclmul-template.S
@@ -136,11 +136,11 @@ 
 // is a vector register containing the needed fold constants, and \tmp is a
 // temporary vector register.  All arguments must be the same length.
 .macro	_fold_vec	acc, data, consts, tmp
 	_pclmulqdq	\consts, HI64_TERMS, \acc, HI64_TERMS, \tmp
 	_pclmulqdq	\consts, LO64_TERMS, \acc, LO64_TERMS, \acc
-.if AVX_LEVEL < 10
+.if AVX_LEVEL <= 2
 	_cond_vex pxor,	\data, \tmp, \tmp
 	_cond_vex pxor,	\tmp, \acc, \acc
 .else
 	vpternlogq	$0x96, \data, \tmp, \acc
 .endif
@@ -199,23 +199,20 @@ 
 // bit0 to x^0, bit1 to x^1, bit7 to x^7.
 //
 // \vl is the maximum length of vector register to use in bytes: 16, 32, or 64.
 //
 // \avx_level is the level of AVX support to use: 0 for SSE only, 2 for AVX2, or
-// 10 for AVX10 or AVX512.
+// 512 for AVX512.
 //
 // If \vl == 16 && \avx_level == 0, the generated code requires:
 // PCLMULQDQ && SSE4.1.  (Note: all known CPUs with PCLMULQDQ also have SSE4.1.)
 //
 // If \vl == 32 && \avx_level == 2, the generated code requires:
 // VPCLMULQDQ && AVX2.
 //
-// If \vl == 32 && \avx_level == 10, the generated code requires:
-// VPCLMULQDQ && (AVX10/256 || (AVX512BW && AVX512VL))
-//
-// If \vl == 64 && \avx_level == 10, the generated code requires:
-// VPCLMULQDQ && (AVX10/512 || (AVX512BW && AVX512VL))
+// If \vl == 64 && \avx_level == 512, the generated code requires:
+// VPCLMULQDQ && AVX512BW && AVX512VL.
 //
 // Other \vl and \avx_level combinations are either not supported or not useful.
 .macro	_crc_pclmul	n, lsb_crc, vl, avx_level
 	.set	LSB_CRC,	\lsb_crc
 	.set	VL,		\vl
@@ -532,11 +529,11 @@ 
 	// floor(t0 / G).  The most efficient way to do that is to move it to
 	// the physically high qword and use a ternlog to combine the two XORs.
 .if LSB_CRC && \n == 64
 	_cond_vex punpcklqdq,	%xmm1, %xmm2, %xmm2
 	_pclmulqdq		CONSTS_XMM, LO64_TERMS, %xmm1, HI64_TERMS, %xmm1
-    .if AVX_LEVEL < 10
+    .if AVX_LEVEL <= 2
 	_cond_vex pxor,		%xmm2, %xmm0, %xmm0
 	_cond_vex pxor,		%xmm1, %xmm0, %xmm0
     .else
 	vpternlogq		$0x96, %xmm2, %xmm1, %xmm0
     .endif
@@ -572,17 +569,13 @@  SYM_FUNC_END(prefix##_pclmul_sse);					\
 									\
 SYM_FUNC_START(prefix##_vpclmul_avx2);					\
 	_crc_pclmul	n=bits, lsb_crc=lsb, vl=32, avx_level=2;	\
 SYM_FUNC_END(prefix##_vpclmul_avx2);					\
 									\
-SYM_FUNC_START(prefix##_vpclmul_avx10_256);				\
-	_crc_pclmul	n=bits, lsb_crc=lsb, vl=32, avx_level=10;	\
-SYM_FUNC_END(prefix##_vpclmul_avx10_256);				\
-									\
-SYM_FUNC_START(prefix##_vpclmul_avx10_512);				\
-	_crc_pclmul	n=bits, lsb_crc=lsb, vl=64, avx_level=10;	\
-SYM_FUNC_END(prefix##_vpclmul_avx10_512);
+SYM_FUNC_START(prefix##_vpclmul_avx512);				\
+	_crc_pclmul	n=bits, lsb_crc=lsb, vl=64, avx_level=512;	\
+SYM_FUNC_END(prefix##_vpclmul_avx512);
 #else
 #define DEFINE_CRC_PCLMUL_FUNCS(prefix, bits, lsb)			\
 SYM_FUNC_START(prefix##_pclmul_sse);					\
 	_crc_pclmul	n=bits, lsb_crc=lsb, vl=16, avx_level=0;	\
 SYM_FUNC_END(prefix##_pclmul_sse);
diff --git a/arch/x86/lib/crc-pclmul-template.h b/arch/x86/lib/crc-pclmul-template.h
index 7b89f0edbc179..c5b3bfe11d8da 100644
--- a/arch/x86/lib/crc-pclmul-template.h
+++ b/arch/x86/lib/crc-pclmul-template.h
@@ -19,31 +19,26 @@ 
 #define DECLARE_CRC_PCLMUL_FUNCS(prefix, crc_t)				\
 crc_t prefix##_pclmul_sse(crc_t crc, const u8 *p, size_t len,		\
 			  const void *consts_ptr);			\
 crc_t prefix##_vpclmul_avx2(crc_t crc, const u8 *p, size_t len,		\
 			    const void *consts_ptr);			\
-crc_t prefix##_vpclmul_avx10_256(crc_t crc, const u8 *p, size_t len,	\
-				 const void *consts_ptr);		\
-crc_t prefix##_vpclmul_avx10_512(crc_t crc, const u8 *p, size_t len,	\
-				 const void *consts_ptr);		\
+crc_t prefix##_vpclmul_avx512(crc_t crc, const u8 *p, size_t len,	\
+			      const void *consts_ptr);			\
 DEFINE_STATIC_CALL(prefix##_pclmul, prefix##_pclmul_sse)
 
 #define INIT_CRC_PCLMUL(prefix)						\
 do {									\
 	if (IS_ENABLED(CONFIG_AS_VPCLMULQDQ) &&				\
 	    boot_cpu_has(X86_FEATURE_VPCLMULQDQ) &&			\
 	    boot_cpu_has(X86_FEATURE_AVX2) &&				\
 	    cpu_has_xfeatures(XFEATURE_MASK_YMM, NULL)) {		\
 		if (boot_cpu_has(X86_FEATURE_AVX512BW) &&		\
 		    boot_cpu_has(X86_FEATURE_AVX512VL) &&		\
+		    !boot_cpu_has(X86_FEATURE_PREFER_YMM) &&		\
 		    cpu_has_xfeatures(XFEATURE_MASK_AVX512, NULL)) {	\
-			if (boot_cpu_has(X86_FEATURE_PREFER_YMM))	\
-				static_call_update(prefix##_pclmul,	\
-						   prefix##_vpclmul_avx10_256); \
-			else						\
-				static_call_update(prefix##_pclmul,	\
-						   prefix##_vpclmul_avx10_512); \
+			static_call_update(prefix##_pclmul,		\
+					   prefix##_vpclmul_avx512);	\
 		} else {						\
 			static_call_update(prefix##_pclmul,		\
 					   prefix##_vpclmul_avx2);	\
 		}							\
 	}								\