From a669c6a4935626786e456b25e9cf2bfbba908f15 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 14 Feb 2024 13:28:59 +0100 Subject: arm64: Add helpers to probe local CPU for PAC and BTI support Add some helpers that will be used by the early kernel mapping code to check feature support on the local CPU. This permits the early kernel mapping to be created with the right attributes, removing the need for tearing it down and recreating it. Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20240214122845.2033971-58-ardb+git@google.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/cpufeature.h | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'arch/arm64/include') diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 03c34242bfc7..e3edae1825f3 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -963,6 +963,38 @@ static inline bool kaslr_disabled_cmdline(void) u32 get_kvm_ipa_limit(void); void dump_cpu_features(void); +static inline bool cpu_has_bti(void) +{ + if (!IS_ENABLED(CONFIG_ARM64_BTI)) + return false; + + return arm64_apply_feature_override(read_cpuid(ID_AA64PFR1_EL1), + ID_AA64PFR1_EL1_BT_SHIFT, 4, + &id_aa64pfr1_override); +} + +static inline bool cpu_has_pac(void) +{ + u64 isar1, isar2; + + if (!IS_ENABLED(CONFIG_ARM64_PTR_AUTH)) + return false; + + isar1 = read_cpuid(ID_AA64ISAR1_EL1); + isar2 = read_cpuid(ID_AA64ISAR2_EL1); + + if (arm64_apply_feature_override(isar1, ID_AA64ISAR1_EL1_APA_SHIFT, 4, + &id_aa64isar1_override)) + return true; + + if (arm64_apply_feature_override(isar1, ID_AA64ISAR1_EL1_API_SHIFT, 4, + &id_aa64isar1_override)) + return true; + + return arm64_apply_feature_override(isar2, ID_AA64ISAR2_EL1_APA3_SHIFT, 4, + &id_aa64isar2_override); +} + #endif /* __ASSEMBLY__ */ #endif -- cgit v1.2.3