arm64/cpufeature: Add remaining feature bits in ID_AA64MMFR0 register

Enable EVC, FGT, EXS features bits in ID_AA64MMFR0 register as per ARM DDI
0487F.a specification.
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/1593748297-1965-2-git-send-email-anshuman.khandual@arm.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/sysreg.h

@@ -706,6 +706,9 @@
 #define ID_AA64ZFR0_SVEVER_SVE2		0x1
 
 /* id_aa64mmfr0 */
+#define ID_AA64MMFR0_ECV_SHIFT		60
+#define ID_AA64MMFR0_FGT_SHIFT		56
+#define ID_AA64MMFR0_EXS_SHIFT		44
 #define ID_AA64MMFR0_TGRAN4_2_SHIFT	40
 #define ID_AA64MMFR0_TGRAN64_2_SHIFT	36
 #define ID_AA64MMFR0_TGRAN16_2_SHIFT	32

arch/arm64/kernel/cpufeature.c

@@ -269,6 +269,9 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ECV_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_FGT_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_EXS_SHIFT, 4, 0),
 	/*
 	 * Page size not being supported at Stage-2 is not fatal. You
 	 * just give up KVM if PAGE_SIZE isn't supported there. Go fix