diff options
| -rw-r--r-- | arch/arm64/include/asm/cpufeature.h | 68 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpu_errata.c | 8 | ||||
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 34 |
3 files changed, 89 insertions, 21 deletions
diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h index 13fde0952c31..b8d8e6012385 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -153,6 +153,7 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; * an action, based on the severity (e.g, a CPU could be prevented from * booting or cause a kernel panic). The CPU is allowed to "affect" the * state of the capability, if it has not been finalised already. + * See section 5 for more details on conflicts. * * 4) Action: As mentioned in (2), the kernel can take an action for each * detected capability, on all CPUs on the system. Appropriate actions @@ -170,6 +171,34 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; * * check_local_cpu_capabilities() -> verify_local_cpu_capabilities() * + * 5) Conflicts: Based on the state of the capability on a late CPU vs. + * the system state, we could have the following combinations : + * + * x-----------------------------x + * | Type | System | Late CPU | + * |-----------------------------| + * | a | y | n | + * |-----------------------------| + * | b | n | y | + * x-----------------------------x + * + * Two separate flag bits are defined to indicate whether each kind of + * conflict can be allowed: + * ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU - Case(a) is allowed + * ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU - Case(b) is allowed + * + * Case (a) is not permitted for a capability that the system requires + * all CPUs to have in order for the capability to be enabled. This is + * typical for capabilities that represent enhanced functionality. + * + * Case (b) is not permitted for a capability that must be enabled + * during boot if any CPU in the system requires it in order to run + * safely. This is typical for erratum work arounds that cannot be + * enabled after the corresponding capability is finalised. + * + * In some non-typical cases either both (a) and (b), or neither, + * should be permitted. This can be described by including neither + * or both flags in the capability's type field. */ @@ -183,6 +212,33 @@ extern struct arm64_ftr_reg arm64_ftr_reg_ctrel0; #define SCOPE_SYSTEM ARM64_CPUCAP_SCOPE_SYSTEM #define SCOPE_LOCAL_CPU ARM64_CPUCAP_SCOPE_LOCAL_CPU +/* + * Is it permitted for a late CPU to have this capability when system + * hasn't already enabled it ? + */ +#define ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU ((u16)BIT(4)) +/* Is it safe for a late CPU to miss this capability when system has it */ +#define ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU ((u16)BIT(5)) + +/* + * CPU errata workarounds that need to be enabled at boot time if one or + * more CPUs in the system requires it. When one of these capabilities + * has been enabled, it is safe to allow any CPU to boot that doesn't + * require the workaround. However, it is not safe if a "late" CPU + * requires a workaround and the system hasn't enabled it already. + */ +#define ARM64_CPUCAP_LOCAL_CPU_ERRATUM \ + (ARM64_CPUCAP_SCOPE_LOCAL_CPU | ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU) +/* + * CPU feature detected at boot time based on system-wide value of a + * feature. It is safe for a late CPU to have this feature even though + * the system hasn't enabled it, although the featuer will not be used + * by Linux in this case. If the system has enabled this feature already, + * then every late CPU must have it. + */ +#define ARM64_CPUCAP_SYSTEM_FEATURE \ + (ARM64_CPUCAP_SCOPE_SYSTEM | ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU) + struct arm64_cpu_capabilities { const char *desc; u16 capability; @@ -220,6 +276,18 @@ static inline int cpucap_default_scope(const struct arm64_cpu_capabilities *cap) return cap->type & ARM64_CPUCAP_SCOPE_MASK; } +static inline bool +cpucap_late_cpu_optional(const struct arm64_cpu_capabilities *cap) +{ + return !!(cap->type & ARM64_CPUCAP_OPTIONAL_FOR_LATE_CPU); +} + +static inline bool +cpucap_late_cpu_permitted(const struct arm64_cpu_capabilities *cap) +{ + return !!(cap->type & ARM64_CPUCAP_PERMITTED_FOR_LATE_CPU); +} + extern DECLARE_BITMAP(cpu_hwcaps, ARM64_NCAPS); extern struct static_key_false cpu_hwcap_keys[ARM64_NCAPS]; extern struct static_key_false arm64_const_caps_ready; diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 2b5233157af1..f5ab9545c5ea 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -238,14 +238,14 @@ qcom_enable_link_stack_sanitization(const struct arm64_cpu_capabilities *entry) #endif /* CONFIG_HARDEN_BRANCH_PREDICTOR */ #define MIDR_RANGE(model, min, max) \ - .type = ARM64_CPUCAP_SCOPE_LOCAL_CPU, \ + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \ .matches = is_affected_midr_range, \ .midr_model = model, \ .midr_range_min = min, \ .midr_range_max = max #define MIDR_ALL_VERSIONS(model) \ - .type = ARM64_CPUCAP_SCOPE_LOCAL_CPU, \ + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, \ .matches = is_affected_midr_range, \ .midr_model = model, \ .midr_range_min = 0, \ @@ -361,7 +361,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = { .desc = "Mismatched cache line size", .capability = ARM64_MISMATCHED_CACHE_LINE_SIZE, .matches = has_mismatched_cache_line_size, - .type = ARM64_CPUCAP_SCOPE_LOCAL_CPU, + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, .cpu_enable = cpu_enable_trap_ctr_access, }, #ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003 @@ -375,7 +375,7 @@ const struct arm64_cpu_capabilities arm64_errata[] = { { .desc = "Qualcomm Technologies Kryo erratum 1003", .capability = ARM64_WORKAROUND_QCOM_FALKOR_E1003, - .type = ARM64_CPUCAP_SCOPE_LOCAL_CPU, + .type = ARM64_CPUCAP_LOCAL_CPU_ERRATUM, .midr_model = MIDR_QCOM_KRYO, .matches = is_kryo_midr, }, diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 19955fd5eb02..0b8e6b9e24e1 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -975,7 +975,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "GIC system register CPU interface", .capability = ARM64_HAS_SYSREG_GIC_CPUIF, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_useable_gicv3_cpuif, .sys_reg = SYS_ID_AA64PFR0_EL1, .field_pos = ID_AA64PFR0_GIC_SHIFT, @@ -986,7 +986,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "Privileged Access Never", .capability = ARM64_HAS_PAN, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cpuid_feature, .sys_reg = SYS_ID_AA64MMFR1_EL1, .field_pos = ID_AA64MMFR1_PAN_SHIFT, @@ -999,7 +999,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "LSE atomic instructions", .capability = ARM64_HAS_LSE_ATOMICS, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cpuid_feature, .sys_reg = SYS_ID_AA64ISAR0_EL1, .field_pos = ID_AA64ISAR0_ATOMICS_SHIFT, @@ -1010,14 +1010,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "Software prefetching using PRFM", .capability = ARM64_HAS_NO_HW_PREFETCH, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_no_hw_prefetch, }, #ifdef CONFIG_ARM64_UAO { .desc = "User Access Override", .capability = ARM64_HAS_UAO, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cpuid_feature, .sys_reg = SYS_ID_AA64MMFR2_EL1, .field_pos = ID_AA64MMFR2_UAO_SHIFT, @@ -1031,21 +1031,21 @@ static const struct arm64_cpu_capabilities arm64_features[] = { #ifdef CONFIG_ARM64_PAN { .capability = ARM64_ALT_PAN_NOT_UAO, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = cpufeature_pan_not_uao, }, #endif /* CONFIG_ARM64_PAN */ { .desc = "Virtualization Host Extensions", .capability = ARM64_HAS_VIRT_HOST_EXTN, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = runs_at_el2, .cpu_enable = cpu_copy_el2regs, }, { .desc = "32-bit EL0 Support", .capability = ARM64_HAS_32BIT_EL0, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cpuid_feature, .sys_reg = SYS_ID_AA64PFR0_EL1, .sign = FTR_UNSIGNED, @@ -1055,14 +1055,14 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "Reduced HYP mapping offset", .capability = ARM64_HYP_OFFSET_LOW, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = hyp_offset_low, }, #ifdef CONFIG_UNMAP_KERNEL_AT_EL0 { .desc = "Kernel page table isolation (KPTI)", .capability = ARM64_UNMAP_KERNEL_AT_EL0, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = unmap_kernel_at_el0, .cpu_enable = kpti_install_ng_mappings, }, @@ -1070,7 +1070,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { /* FP/SIMD is not implemented */ .capability = ARM64_HAS_NO_FPSIMD, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .min_field_value = 0, .matches = has_no_fpsimd, }, @@ -1078,7 +1078,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "Data cache clean to Point of Persistence", .capability = ARM64_HAS_DCPOP, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cpuid_feature, .sys_reg = SYS_ID_AA64ISAR1_EL1, .field_pos = ID_AA64ISAR1_DPB_SHIFT, @@ -1088,7 +1088,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { #ifdef CONFIG_ARM64_SVE { .desc = "Scalable Vector Extension", - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .capability = ARM64_SVE, .sys_reg = SYS_ID_AA64PFR0_EL1, .sign = FTR_UNSIGNED, @@ -1102,7 +1102,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "RAS Extension Support", .capability = ARM64_HAS_RAS_EXTN, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cpuid_feature, .sys_reg = SYS_ID_AA64PFR0_EL1, .sign = FTR_UNSIGNED, @@ -1114,13 +1114,13 @@ static const struct arm64_cpu_capabilities arm64_features[] = { { .desc = "Data cache clean to the PoU not required for I/D coherence", .capability = ARM64_HAS_CACHE_IDC, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cache_idc, }, { .desc = "Instruction cache invalidation not required for I/D coherence", .capability = ARM64_HAS_CACHE_DIC, - .type = ARM64_CPUCAP_SCOPE_SYSTEM, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_cache_dic, }, {}, @@ -1129,7 +1129,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { #define HWCAP_CAP(reg, field, s, min_value, cap_type, cap) \ { \ .desc = #cap, \ - .type = ARM64_CPUCAP_SCOPE_SYSTEM, \ + .type = ARM64_CPUCAP_SYSTEM_FEATURE, \ .matches = has_cpuid_feature, \ .sys_reg = reg, \ .field_pos = field, \ |