diff options
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 5 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 38 | ||||
| -rw-r--r-- | arch/arm64/tools/cpucaps | 1 |
3 files changed, 44 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 155ebd040c55..bf13d676aae2 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -871,6 +871,11 @@ static inline bool system_supports_pmuv3(void) return cpus_have_final_cap(ARM64_HAS_PMUV3); } +static inline bool system_supports_bbml2_noabort(void) +{ + return alternative_has_cap_unlikely(ARM64_HAS_BBML2_NOABORT); +} + 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 f9c947166322..2b6e70bad72a 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -2213,6 +2213,38 @@ static bool hvhe_possible(const struct arm64_cpu_capabilities *entry, return arm64_test_sw_feature_override(ARM64_SW_FEATURE_OVERRIDE_HVHE); } +static bool has_bbml2_noabort(const struct arm64_cpu_capabilities *caps, int scope) +{ + /* + * We want to allow usage of BBML2 in as wide a range of kernel contexts + * as possible. This list is therefore an allow-list of known-good + * implementations that both support BBML2 and additionally, fulfill the + * extra constraint of never generating TLB conflict aborts when using + * the relaxed BBML2 semantics (such aborts make use of BBML2 in certain + * kernel contexts difficult to prove safe against recursive aborts). + * + * Note that implementations can only be considered "known-good" if their + * implementors attest to the fact that the implementation never raises + * TLB conflict aborts for BBML2 mapping granularity changes. + */ + static const struct midr_range supports_bbml2_noabort_list[] = { + MIDR_REV_RANGE(MIDR_CORTEX_X4, 0, 3, 0xf), + MIDR_REV_RANGE(MIDR_NEOVERSE_V3, 0, 2, 0xf), + {} + }; + + /* Does our cpu guarantee to never raise TLB conflict aborts? */ + if (!is_midr_in_range_list(supports_bbml2_noabort_list)) + return false; + + /* + * We currently ignore the ID_AA64MMFR2_EL1 register, and only care + * about whether the MIDR check passes. + */ + + return true; +} + #ifdef CONFIG_ARM64_PAN static void cpu_enable_pan(const struct arm64_cpu_capabilities *__unused) { @@ -2981,6 +3013,12 @@ static const struct arm64_cpu_capabilities arm64_features[] = { ARM64_CPUID_FIELDS(ID_AA64MMFR2_EL1, EVT, IMP) }, { + .desc = "BBM Level 2 without TLB conflict abort", + .capability = ARM64_HAS_BBML2_NOABORT, + .type = ARM64_CPUCAP_EARLY_LOCAL_CPU_FEATURE, + .matches = has_bbml2_noabort, + }, + { .desc = "52-bit Virtual Addressing for KVM (LPA2)", .capability = ARM64_HAS_LPA2, .type = ARM64_CPUCAP_SYSTEM_FEATURE, diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index 10effd4cff6b..2bd2bfaeddcd 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -45,6 +45,7 @@ HAS_LPA2 HAS_LSE_ATOMICS HAS_MOPS HAS_NESTED_VIRT +HAS_BBML2_NOABORT HAS_PAN HAS_PMUV3 HAS_S1PIE |