ARM: 9272/1: vfp: Add hwcap for FEAT_AA32I8MM

Int8 matrix multiplication (FEAT_AA32I8MM) is a feature present in AArch32 state for Armv8 and is represented by ISAR6.I8MM identification register.

This feature denotes the presence of VSMMLA, VSUDOT, VUMMLA, VUSMMLA and
VUSDOT instructions and hence adding a hwcap will enable the userspace
to check it before trying to use those instructions.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Amit Daniel Kachhap <amit.kachhap@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

arch/arm/include/uapi/asm/hwcap.h

@@ -33,6 +33,7 @@
 #define HWCAP_ASIMDDP	(1 << 24)
 #define HWCAP_ASIMDFHM	(1 << 25)
 #define HWCAP_ASIMDBF16	(1 << 26)
+#define HWCAP_I8MM	(1 << 27)
 
 /*
  * HWCAP2 flags - for elf_hwcap2 (in kernel) and AT_HWCAP2

arch/arm/kernel/setup.c

@@ -1254,6 +1254,7 @@ static const char *hwcap_str[] = {
 	"asimddp",
 	"asimdfhm",
 	"asimdbf16",
+	"i8mm",
 	NULL
 };
 

arch/arm/vfp/vfpmodule.c

@@ -857,6 +857,12 @@ static int __init vfp_init(void)
 		 */
 		if (cpuid_feature_extract_field(isar6, 20) == 0x1)
 			elf_hwcap |= HWCAP_ASIMDBF16;
+		/*
+		 * Check for the presence of Advanced SIMD and floating point
+		 * Int8 matrix multiplication instructions instructions.
+		 */
+		if (cpuid_feature_extract_field(isar6, 24) == 0x1)
+			elf_hwcap |= HWCAP_I8MM;
 
 	/* Extract the architecture version on pre-cpuid scheme */
 	} else {