diff options
| -rw-r--r-- | arch/arm64/kernel/cpuinfo.c | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 3ce99fc1fde1..f82f7d1c468e 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -21,6 +21,7 @@ #include <linux/bitops.h> #include <linux/init.h> +#include <linux/kernel.h> #include <linux/printk.h> #include <linux/smp.h> @@ -54,6 +55,97 @@ static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info) pr_info("Detected %s I-cache on CPU%d", icache_policy_str[l1ip], cpu); } +static int check_reg_mask(char *name, u64 mask, u64 boot, u64 cur, int cpu) +{ + if ((boot & mask) == (cur & mask)) + return 0; + + pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016lx, CPU%d: %#016lx\n", + name, (unsigned long)boot, cpu, (unsigned long)cur); + + return 1; +} + +#define CHECK_MASK(field, mask, boot, cur, cpu) \ + check_reg_mask(#field, mask, (boot)->reg_ ## field, (cur)->reg_ ## field, cpu) + +#define CHECK(field, boot, cur, cpu) \ + CHECK_MASK(field, ~0ULL, boot, cur, cpu) + +/* + * Verify that CPUs don't have unexpected differences that will cause problems. + */ +static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur) +{ + unsigned int cpu = smp_processor_id(); + struct cpuinfo_arm64 *boot = &boot_cpu_data; + unsigned int diff = 0; + + /* + * The kernel can handle differing I-cache policies, but otherwise + * caches should look identical. Userspace JITs will make use of + * *minLine. + */ + diff |= CHECK_MASK(ctr, 0xffff3fff, boot, cur, cpu); + + /* + * Userspace may perform DC ZVA instructions. Mismatched block sizes + * could result in too much or too little memory being zeroed if a + * process is preempted and migrated between CPUs. + */ + diff |= CHECK(dczid, boot, cur, cpu); + + /* If different, timekeeping will be broken (especially with KVM) */ + diff |= CHECK(cntfrq, boot, cur, cpu); + + /* + * Even in big.LITTLE, processors should be identical instruction-set + * wise. + */ + diff |= CHECK(id_aa64isar0, boot, cur, cpu); + diff |= CHECK(id_aa64isar1, boot, cur, cpu); + + /* + * Differing PARange support is fine as long as all peripherals and + * memory are mapped within the minimum PARange of all CPUs. + * Linux should not care about secure memory. + * ID_AA64MMFR1 is currently RES0. + */ + diff |= CHECK_MASK(id_aa64mmfr0, 0xffffffffffff0ff0, boot, cur, cpu); + diff |= CHECK(id_aa64mmfr1, boot, cur, cpu); + + /* + * EL3 is not our concern. + * ID_AA64PFR1 is currently RES0. + */ + diff |= CHECK_MASK(id_aa64pfr0, 0xffffffffffff0fff, boot, cur, cpu); + diff |= CHECK(id_aa64pfr1, boot, cur, cpu); + + /* + * If we have AArch32, we care about 32-bit features for compat. These + * registers should be RES0 otherwise. + */ + diff |= CHECK(id_isar0, boot, cur, cpu); + diff |= CHECK(id_isar1, boot, cur, cpu); + diff |= CHECK(id_isar2, boot, cur, cpu); + diff |= CHECK(id_isar3, boot, cur, cpu); + diff |= CHECK(id_isar4, boot, cur, cpu); + diff |= CHECK(id_isar5, boot, cur, cpu); + diff |= CHECK(id_mmfr0, boot, cur, cpu); + diff |= CHECK(id_mmfr1, boot, cur, cpu); + diff |= CHECK(id_mmfr2, boot, cur, cpu); + diff |= CHECK(id_mmfr3, boot, cur, cpu); + diff |= CHECK(id_pfr0, boot, cur, cpu); + diff |= CHECK(id_pfr1, boot, cur, cpu); + + /* + * Mismatched CPU features are a recipe for disaster. Don't even + * pretend to support them. + */ + WARN_TAINT_ONCE(diff, TAINT_CPU_OUT_OF_SPEC, + "Unsupported CPU feature variation."); +} + static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info) { info->reg_cntfrq = arch_timer_get_cntfrq(); @@ -88,6 +180,7 @@ void cpuinfo_store_cpu(void) { struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data); __cpuinfo_store_cpu(info); + cpuinfo_sanity_check(info); } void __init cpuinfo_store_boot_cpu(void) |