arm64/cpufeature: Add MTE_STORE_ONLY feature

Since ARMv8.9, FEAT_MTE_STORE_ONLY can be used to restrict raise of tag
check fault on store operation only.

add MTE_STORE_ONLY feature.

Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250618092957.2069907-2-yeoreum.yun@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 8a5284c733b724751dbe2d5168d22ff2b828374f..fdc48aa1f0e23720c004d8cd4d082fc3ae841aae 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -321,6 +321,7 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = {
 static const struct arm64_ftr_bits ftr_id_aa64pfr2[] = {
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_FPMR_SHIFT, 4, 0),
        ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_MTEFAR_SHIFT, 4, ID_AA64PFR2_EL1_MTEFAR_NI),
+       ARM64_FTR_BITS(FTR_VISIBLE, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64PFR2_EL1_MTESTOREONLY_SHIFT, 4, ID_AA64PFR2_EL1_MTESTOREONLY_NI),
        ARM64_FTR_END,
 };
 
@@ -2882,6 +2883,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
                .matches = has_cpuid_feature,
                ARM64_CPUID_FIELDS(ID_AA64PFR2_EL1, MTEFAR, IMP)
        },
+       {
+               .desc = "Store Only MTE Tag Check",
+               .capability = ARM64_MTE_STORE_ONLY,
+               .type = ARM64_CPUCAP_SYSTEM_FEATURE,
+               .matches = has_cpuid_feature,
+               ARM64_CPUID_FIELDS(ID_AA64PFR2_EL1, MTESTOREONLY, IMP)
+       },
 #endif /* CONFIG_ARM64_MTE */
        {
                .desc = "RCpc load-acquire (LDAPR)",

diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index fe8f4f8ce95cd5d57ba51f8c6259c548868eee7b..b96cb6d6bcaaf79e44f58e15203a2ccd60ff7d30 100644 (file)
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -69,6 +69,7 @@ MPAM_HCR
 MTE
 MTE_ASYMM
 MTE_FAR
+MTE_STORE_ONLY
 SME
 SME_FA64
 SME2