[PATCH 02/10] arm64: cpufeature: detect FEAT_HCX

[Kristina Martsenko]

Detect if the system has the new HCRX_EL2 register added in ARMv8.7/9.2,
so that subsequent patches can check for its presence.

Signed-off-by: Kristina Martsenko <kristina.martsenko@xxxxxxx>
---
 arch/arm64/kernel/cpufeature.c | 12 ++++++++++++
 arch/arm64/tools/cpucaps       |  1 +
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 45a42cf2191c..1b0a71541381 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -357,6 +357,7 @@ static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
 static const struct arm64_ftr_bits ftr_id_aa64mmfr1[] = {
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_TIDCP1_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_AFP_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_HCX_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_ETS_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_TWED_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR1_EL1_XNX_SHIFT, 4, 0),
@@ -2290,6 +2291,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
 		.matches = is_kvm_protected_mode,
 	},
+	{
+		.desc = "HCRX_EL2 register",
+		.capability = ARM64_HAS_HCX,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.sys_reg = SYS_ID_AA64MMFR1_EL1,
+		.sign = FTR_UNSIGNED,
+		.field_pos = ID_AA64MMFR1_EL1_HCX_SHIFT,
+		.field_width = 4,
+		.min_field_value = ID_AA64MMFR1_EL1_HCX_IMP,
+		.matches = has_cpuid_feature,
+	},
 #endif
 	{
 		.desc = "Kernel page table isolation (KPTI)",
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 10dcfa13390a..bf32a1122c04 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -31,6 +31,7 @@ HAS_GENERIC_AUTH_IMP_DEF
 HAS_GIC_CPUIF_SYSREGS
 HAS_GIC_PRIO_MASKING
 HAS_GIC_PRIO_RELAXED_SYNC
+HAS_HCX
 HAS_LDAPR
 HAS_LSE_ATOMICS
 HAS_NO_FPSIMD
-- 
2.25.1