[PATCH v4 17/22] x86/cpufeatures/amx: Enumerate Advanced Matrix Extension (AMX) feature bits

[Chang S. Bae]

Intel's Advanced Matrix Extension (AMX) is a new 64-bit extended feature
consisting of two-dimensional registers and an accelerator unit. The first
implementation of the latter is the tile matrix multiply unit (TMUL). TMUL
performs SIMD dot-products on four bytes (INT8) or two bfloat16
floating-point (BF16) elements.

Here we add AMX to the kernel/user ABI, by enumerating the capability.
E.g., /proc/cpuinfo: amx_tile, amx_bf16, amx_int8

Signed-off-by: Chang S. Bae <chang.seok.bae@xxxxxxxxx>
Reviewed-by: Len Brown <len.brown@xxxxxxxxx>
Cc: x86@xxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
 arch/x86/include/asm/cpufeatures.h | 3 +++
 arch/x86/kernel/cpu/cpuid-deps.c   | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 3170ab367cf2..f9990841238a 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -379,6 +379,9 @@
 #define X86_FEATURE_PCONFIG		(18*32+18) /* Intel PCONFIG */
 #define X86_FEATURE_ARCH_LBR		(18*32+19) /* Intel ARCH LBR */
 #define X86_FEATURE_AVX512_FP16		(18*32+23) /* AVX512 FP16 */
+#define X86_FEATURE_AMX_BF16		(18*32+22) /* AMX BF16 Support */
+#define X86_FEATURE_AMX_TILE		(18*32+24) /* AMX tile Support */
+#define X86_FEATURE_AMX_INT8		(18*32+25) /* AMX INT8 Support */
 #define X86_FEATURE_SPEC_CTRL		(18*32+26) /* "" Speculation Control (IBRS + IBPB) */
 #define X86_FEATURE_INTEL_STIBP		(18*32+27) /* "" Single Thread Indirect Branch Predictors */
 #define X86_FEATURE_FLUSH_L1D		(18*32+28) /* Flush L1D cache */
diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 4423046c2d74..154c18e493c5 100644
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -73,6 +73,9 @@ static const struct cpuid_dep cpuid_deps[] = {
 	{ X86_FEATURE_ENQCMD,			X86_FEATURE_XSAVES    },
 	{ X86_FEATURE_PER_THREAD_MBA,		X86_FEATURE_MBA       },
 	{ X86_FEATURE_XFD,			X86_FEATURE_XSAVES    },
+	{ X86_FEATURE_AMX_TILE,			X86_FEATURE_XSAVE     },
+	{ X86_FEATURE_AMX_INT8,			X86_FEATURE_AMX_TILE  },
+	{ X86_FEATURE_AMX_BF16,			X86_FEATURE_AMX_TILE  },
 	{}
 };
 
-- 
2.17.1