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>

arch/arm64/include/asm/cpucaps.h

@@ -63,7 +63,8 @@
 #define ARM64_HAS_32BIT_EL1			53
 #define ARM64_BTI				54
 #define ARM64_HAS_ARMv8_4_TTL			55
+#define ARM64_HAS_TLB_RANGE			56
 
-#define ARM64_NCAPS				56
+#define ARM64_NCAPS				57
 
 #endif /* __ASM_CPUCAPS_H */

arch/arm64/include/asm/sysreg.h

@@ -617,6 +617,9 @@
 #define ID_AA64ISAR0_SHA1_SHIFT		8
 #define ID_AA64ISAR0_AES_SHIFT		4
 
+#define ID_AA64ISAR0_TLB_RANGE_NI	0x0
+#define ID_AA64ISAR0_TLB_RANGE		0x2
+
 /* id_aa64isar1 */
 #define ID_AA64ISAR1_I8MM_SHIFT		52
 #define ID_AA64ISAR1_DGH_SHIFT		48

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
 	{
 		/*