Add a cpufeature for GCS, allowing other code to conditionally support it at runtime.
Reviewed-by: Thiago Jung Bauermann thiago.bauermann@linaro.org Signed-off-by: Mark Brown broonie@kernel.org --- arch/arm64/include/asm/cpufeature.h | 6 ++++++ arch/arm64/kernel/cpufeature.c | 9 +++++++++ arch/arm64/tools/cpucaps | 1 + 3 files changed, 16 insertions(+)
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 558434267271..e0f0e4c24544 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -832,6 +832,12 @@ static inline bool system_supports_lpa2(void) return cpus_have_final_cap(ARM64_HAS_LPA2); }
+static inline bool system_supports_gcs(void) +{ + return IS_ENABLED(CONFIG_ARM64_GCS) && + alternative_has_cap_unlikely(ARM64_HAS_GCS); +} + int do_emulate_mrs(struct pt_regs *regs, u32 sys_reg, u32 rt); bool try_emulate_mrs(struct pt_regs *regs, u32 isn);
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 646ecd3069fd..315bd7be1106 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -291,6 +291,8 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[] = { };
static const struct arm64_ftr_bits ftr_id_aa64pfr1[] = { + ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_GCS), + FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_GCS_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_SME), FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_SME_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_EL1_MPAM_frac_SHIFT, 4, 0), @@ -2870,6 +2872,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .matches = has_nv1, ARM64_CPUID_FIELDS_NEG(ID_AA64MMFR4_EL1, E2H0, NI_NV1) }, + { + .desc = "Guarded Control Stack (GCS)", + .capability = ARM64_HAS_GCS, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_cpuid_feature, + ARM64_CPUID_FIELDS(ID_AA64PFR1_EL1, GCS, IMP) + }, {}, };
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index ac3429d892b9..66eff95c0824 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -29,6 +29,7 @@ HAS_EVT HAS_FPMR HAS_FGT HAS_FPSIMD +HAS_GCS HAS_GENERIC_AUTH HAS_GENERIC_AUTH_ARCH_QARMA3 HAS_GENERIC_AUTH_ARCH_QARMA5