diff options
Diffstat (limited to 'arch/arm64/kernel/cpufeature.c')
| -rw-r--r-- | arch/arm64/kernel/cpufeature.c | 209 |
1 files changed, 161 insertions, 48 deletions
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index efed2830d141..dbae006f625f 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -108,6 +108,24 @@ bool arm64_use_ng_mappings = false; EXPORT_SYMBOL(arm64_use_ng_mappings); /* + * Permit PER_LINUX32 and execve() of 32-bit binaries even if not all CPUs + * support it? + */ +static bool __read_mostly allow_mismatched_32bit_el0; + +/* + * Static branch enabled only if allow_mismatched_32bit_el0 is set and we have + * seen at least one CPU capable of 32-bit EL0. + */ +DEFINE_STATIC_KEY_FALSE(arm64_mismatched_32bit_el0); + +/* + * Mask of CPUs supporting 32-bit EL0. + * Only valid if arm64_mismatched_32bit_el0 is enabled. + */ +static cpumask_var_t cpu_32bit_el0_mask __cpumask_var_read_mostly; + +/* * Flag to indicate if we have computed the system wide * capabilities based on the boot time active CPUs. This * will be used to determine if a new booting CPU should @@ -400,6 +418,11 @@ static const struct arm64_ftr_bits ftr_dczid[] = { ARM64_FTR_END, }; +static const struct arm64_ftr_bits ftr_gmid[] = { + ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, SYS_GMID_EL1_BS_SHIFT, 4, 0), + ARM64_FTR_END, +}; + static const struct arm64_ftr_bits ftr_id_isar0[] = { ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_DIVIDE_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_ISAR0_DEBUG_SHIFT, 4, 0), @@ -617,6 +640,9 @@ static const struct __ftr_reg_entry { /* Op1 = 0, CRn = 1, CRm = 2 */ ARM64_FTR_REG(SYS_ZCR_EL1, ftr_zcr), + /* Op1 = 1, CRn = 0, CRm = 0 */ + ARM64_FTR_REG(SYS_GMID_EL1, ftr_gmid), + /* Op1 = 3, CRn = 0, CRm = 0 */ { SYS_CTR_EL0, &arm64_ftr_reg_ctrel0 }, ARM64_FTR_REG(SYS_DCZID_EL0, ftr_dczid), @@ -767,7 +793,7 @@ static void __init sort_ftr_regs(void) * Any bits that are not covered by an arm64_ftr_bits entry are considered * RES0 for the system-wide value, and must strictly match. */ -static void __init init_cpu_ftr_reg(u32 sys_reg, u64 new) +static void init_cpu_ftr_reg(u32 sys_reg, u64 new) { u64 val = 0; u64 strict_mask = ~0x0ULL; @@ -863,6 +889,31 @@ static void __init init_cpu_hwcaps_indirect_list(void) static void __init setup_boot_cpu_capabilities(void); +static void init_32bit_cpu_features(struct cpuinfo_32bit *info) +{ + init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0); + init_cpu_ftr_reg(SYS_ID_DFR1_EL1, info->reg_id_dfr1); + init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0); + init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1); + init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2); + init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3); + init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4); + init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5); + init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6); + init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0); + init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1); + init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2); + init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3); + init_cpu_ftr_reg(SYS_ID_MMFR4_EL1, info->reg_id_mmfr4); + init_cpu_ftr_reg(SYS_ID_MMFR5_EL1, info->reg_id_mmfr5); + init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0); + init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1); + init_cpu_ftr_reg(SYS_ID_PFR2_EL1, info->reg_id_pfr2); + init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0); + init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1); + init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2); +} + void __init init_cpu_features(struct cpuinfo_arm64 *info) { /* Before we start using the tables, make sure it is sorted */ @@ -882,35 +933,17 @@ void __init init_cpu_features(struct cpuinfo_arm64 *info) init_cpu_ftr_reg(SYS_ID_AA64PFR1_EL1, info->reg_id_aa64pfr1); init_cpu_ftr_reg(SYS_ID_AA64ZFR0_EL1, info->reg_id_aa64zfr0); - if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) { - init_cpu_ftr_reg(SYS_ID_DFR0_EL1, info->reg_id_dfr0); - init_cpu_ftr_reg(SYS_ID_DFR1_EL1, info->reg_id_dfr1); - init_cpu_ftr_reg(SYS_ID_ISAR0_EL1, info->reg_id_isar0); - init_cpu_ftr_reg(SYS_ID_ISAR1_EL1, info->reg_id_isar1); - init_cpu_ftr_reg(SYS_ID_ISAR2_EL1, info->reg_id_isar2); - init_cpu_ftr_reg(SYS_ID_ISAR3_EL1, info->reg_id_isar3); - init_cpu_ftr_reg(SYS_ID_ISAR4_EL1, info->reg_id_isar4); - init_cpu_ftr_reg(SYS_ID_ISAR5_EL1, info->reg_id_isar5); - init_cpu_ftr_reg(SYS_ID_ISAR6_EL1, info->reg_id_isar6); - init_cpu_ftr_reg(SYS_ID_MMFR0_EL1, info->reg_id_mmfr0); - init_cpu_ftr_reg(SYS_ID_MMFR1_EL1, info->reg_id_mmfr1); - init_cpu_ftr_reg(SYS_ID_MMFR2_EL1, info->reg_id_mmfr2); - init_cpu_ftr_reg(SYS_ID_MMFR3_EL1, info->reg_id_mmfr3); - init_cpu_ftr_reg(SYS_ID_MMFR4_EL1, info->reg_id_mmfr4); - init_cpu_ftr_reg(SYS_ID_MMFR5_EL1, info->reg_id_mmfr5); - init_cpu_ftr_reg(SYS_ID_PFR0_EL1, info->reg_id_pfr0); - init_cpu_ftr_reg(SYS_ID_PFR1_EL1, info->reg_id_pfr1); - init_cpu_ftr_reg(SYS_ID_PFR2_EL1, info->reg_id_pfr2); - init_cpu_ftr_reg(SYS_MVFR0_EL1, info->reg_mvfr0); - init_cpu_ftr_reg(SYS_MVFR1_EL1, info->reg_mvfr1); - init_cpu_ftr_reg(SYS_MVFR2_EL1, info->reg_mvfr2); - } + if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) + init_32bit_cpu_features(&info->aarch32); if (id_aa64pfr0_sve(info->reg_id_aa64pfr0)) { init_cpu_ftr_reg(SYS_ZCR_EL1, info->reg_zcr); sve_init_vq_map(); } + if (id_aa64pfr1_mte(info->reg_id_aa64pfr1)) + init_cpu_ftr_reg(SYS_GMID_EL1, info->reg_gmid); + /* * Initialize the indirect array of CPU hwcaps capabilities pointers * before we handle the boot CPU below. @@ -975,21 +1008,29 @@ static void relax_cpu_ftr_reg(u32 sys_id, int field) WARN_ON(!ftrp->width); } -static int update_32bit_cpu_features(int cpu, struct cpuinfo_arm64 *info, - struct cpuinfo_arm64 *boot) +static void lazy_init_32bit_cpu_features(struct cpuinfo_arm64 *info, + struct cpuinfo_arm64 *boot) +{ + static bool boot_cpu_32bit_regs_overridden = false; + + if (!allow_mismatched_32bit_el0 || boot_cpu_32bit_regs_overridden) + return; + + if (id_aa64pfr0_32bit_el0(boot->reg_id_aa64pfr0)) + return; + + boot->aarch32 = info->aarch32; + init_32bit_cpu_features(&boot->aarch32); + boot_cpu_32bit_regs_overridden = true; +} + +static int update_32bit_cpu_features(int cpu, struct cpuinfo_32bit *info, + struct cpuinfo_32bit *boot) { int taint = 0; u64 pfr0 = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1); /* - * If we don't have AArch32 at all then skip the checks entirely - * as the register values may be UNKNOWN and we're not going to be - * using them for anything. - */ - if (!id_aa64pfr0_32bit_el0(pfr0)) - return taint; - - /* * If we don't have AArch32 at EL1, then relax the strictness of * EL1-dependent register fields to avoid spurious sanity check fails. */ @@ -1135,10 +1176,29 @@ void update_cpu_features(int cpu, } /* + * The kernel uses the LDGM/STGM instructions and the number of tags + * they read/write depends on the GMID_EL1.BS field. Check that the + * value is the same on all CPUs. + */ + if (IS_ENABLED(CONFIG_ARM64_MTE) && + id_aa64pfr1_mte(info->reg_id_aa64pfr1)) { + taint |= check_update_ftr_reg(SYS_GMID_EL1, cpu, + info->reg_gmid, boot->reg_gmid); + } + + /* + * If we don't have AArch32 at all then skip the checks entirely + * as the register values may be UNKNOWN and we're not going to be + * using them for anything. + * * This relies on a sanitised view of the AArch64 ID registers * (e.g. SYS_ID_AA64PFR0_EL1), so we call it last. */ - taint |= update_32bit_cpu_features(cpu, info, boot); + if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) { + lazy_init_32bit_cpu_features(info, boot); + taint |= update_32bit_cpu_features(cpu, &info->aarch32, + &boot->aarch32); + } /* * Mismatched CPU features are a recipe for disaster. Don't even @@ -1248,6 +1308,28 @@ has_cpuid_feature(const struct arm64_cpu_capabilities *entry, int scope) return feature_matches(val, entry); } +const struct cpumask *system_32bit_el0_cpumask(void) +{ + if (!system_supports_32bit_el0()) + return cpu_none_mask; + + if (static_branch_unlikely(&arm64_mismatched_32bit_el0)) + return cpu_32bit_el0_mask; + + return cpu_possible_mask; +} + +static bool has_32bit_el0(const struct arm64_cpu_capabilities *entry, int scope) +{ + if (!has_cpuid_feature(entry, scope)) + return allow_mismatched_32bit_el0; + + if (scope == SCOPE_SYSTEM) + pr_info("detected: 32-bit EL0 Support\n"); + + return true; +} + static bool has_useable_gicv3_cpuif(const struct arm64_cpu_capabilities *entry, int scope) { bool has_sre; @@ -1866,10 +1948,9 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .cpu_enable = cpu_copy_el2regs, }, { - .desc = "32-bit EL0 Support", - .capability = ARM64_HAS_32BIT_EL0, + .capability = ARM64_HAS_32BIT_EL0_DO_NOT_USE, .type = ARM64_CPUCAP_SYSTEM_FEATURE, - .matches = has_cpuid_feature, + .matches = has_32bit_el0, .sys_reg = SYS_ID_AA64PFR0_EL1, .sign = FTR_UNSIGNED, .field_pos = ID_AA64PFR0_EL0_SHIFT, @@ -2378,7 +2459,7 @@ static const struct arm64_cpu_capabilities compat_elf_hwcaps[] = { {}, }; -static void __init cap_set_elf_hwcap(const struct arm64_cpu_capabilities *cap) +static void cap_set_elf_hwcap(const struct arm64_cpu_capabilities *cap) { switch (cap->hwcap_type) { case CAP_HWCAP: @@ -2423,7 +2504,7 @@ static bool cpus_have_elf_hwcap(const struct arm64_cpu_capabilities *cap) return rc; } -static void __init setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps) +static void setup_elf_hwcaps(const struct arm64_cpu_capabilities *hwcaps) { /* We support emulation of accesses to CPU ID feature registers */ cpu_set_named_feature(CPUID); @@ -2598,7 +2679,7 @@ static void check_early_cpu_features(void) } static void -verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps) +__verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps) { for (; caps->matches; caps++) @@ -2609,6 +2690,14 @@ verify_local_elf_hwcaps(const struct arm64_cpu_capabilities *caps) } } +static void verify_local_elf_hwcaps(void) +{ + __verify_local_elf_hwcaps(arm64_elf_hwcaps); + + if (id_aa64pfr0_32bit_el0(read_cpuid(ID_AA64PFR0_EL1))) + __verify_local_elf_hwcaps(compat_elf_hwcaps); +} + static void verify_sve_features(void) { u64 safe_zcr = read_sanitised_ftr_reg(SYS_ZCR_EL1); @@ -2673,11 +2762,7 @@ static void verify_local_cpu_capabilities(void) * on all secondary CPUs. */ verify_local_cpu_caps(SCOPE_ALL & ~SCOPE_BOOT_CPU); - - verify_local_elf_hwcaps(arm64_elf_hwcaps); - - if (system_supports_32bit_el0()) - verify_local_elf_hwcaps(compat_elf_hwcaps); + verify_local_elf_hwcaps(); if (system_supports_sve()) verify_sve_features(); @@ -2812,6 +2897,34 @@ void __init setup_cpu_features(void) ARCH_DMA_MINALIGN); } +static int enable_mismatched_32bit_el0(unsigned int cpu) +{ + struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu); + bool cpu_32bit = id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0); + + if (cpu_32bit) { + cpumask_set_cpu(cpu, cpu_32bit_el0_mask); + static_branch_enable_cpuslocked(&arm64_mismatched_32bit_el0); + setup_elf_hwcaps(compat_elf_hwcaps); + } + + return 0; +} + +static int __init init_32bit_el0_mask(void) +{ + if (!allow_mismatched_32bit_el0) + return 0; + + if (!zalloc_cpumask_var(&cpu_32bit_el0_mask, GFP_KERNEL)) + return -ENOMEM; + + return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, + "arm64/mismatched_32bit_el0:online", + enable_mismatched_32bit_el0, NULL); +} +subsys_initcall_sync(init_32bit_el0_mask); + static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap) { cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); @@ -2905,8 +3018,8 @@ static int emulate_mrs(struct pt_regs *regs, u32 insn) } static struct undef_hook mrs_hook = { - .instr_mask = 0xfff00000, - .instr_val = 0xd5300000, + .instr_mask = 0xffff0000, + .instr_val = 0xd5380000, .pstate_mask = PSR_AA32_MODE_MASK, .pstate_val = PSR_MODE_EL0t, .fn = emulate_mrs, |