arm64: tlb: Detect the ARMv8.4 TLBI RANGE feature

ARMv8.4-TLBI provides TLBI invalidation instruction that apply to a
range of input addresses. This patch detect this feature.

Signed-off-by: Zhenyu Ye <yezhenyu2@huawei.com>
Link: https://lore.kernel.org/r/20200715071945.897-2-yezhenyu2@huawei.com
[catalin.marinas@arm.com: some renaming for consistency]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index e877f56..2f5adef 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -1893,6 +1893,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.min_field_value = 1,
 		.matches = has_cpuid_feature,
 	},
+	{
+		.desc = "TLB range maintenance instructions",
+		.capability = ARM64_HAS_TLB_RANGE,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.matches = has_cpuid_feature,
+		.sys_reg = SYS_ID_AA64ISAR0_EL1,
+		.field_pos = ID_AA64ISAR0_TLB_SHIFT,
+		.sign = FTR_UNSIGNED,
+		.min_field_value = ID_AA64ISAR0_TLB_RANGE,
+	},
 #ifdef CONFIG_ARM64_HW_AFDBM
 	{
 		/*