diff options
Diffstat (limited to 'arch/arm64/kernel/cpuinfo.c')
| -rw-r--r-- | arch/arm64/kernel/cpuinfo.c | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c new file mode 100644 index 000000000000..f798f66634af --- /dev/null +++ b/arch/arm64/kernel/cpuinfo.c @@ -0,0 +1,192 @@ +/* + * Record and handle CPU attributes. + * + * Copyright (C) 2014 ARM Ltd. + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <asm/arch_timer.h> +#include <asm/cachetype.h> +#include <asm/cpu.h> +#include <asm/cputype.h> + +#include <linux/bitops.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/printk.h> +#include <linux/smp.h> + +/* + * In case the boot CPU is hotpluggable, we record its initial state and + * current state separately. Certain system registers may contain different + * values depending on configuration at or after reset. + */ +DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data); +static struct cpuinfo_arm64 boot_cpu_data; + +static char *icache_policy_str[] = { + [ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN", + [ICACHE_POLICY_AIVIVT] = "AIVIVT", + [ICACHE_POLICY_VIPT] = "VIPT", + [ICACHE_POLICY_PIPT] = "PIPT", +}; + +unsigned long __icache_flags; + +static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info) +{ + unsigned int cpu = smp_processor_id(); + u32 l1ip = CTR_L1IP(info->reg_ctr); + + if (l1ip != ICACHE_POLICY_PIPT) + set_bit(ICACHEF_ALIASING, &__icache_flags); + if (l1ip == ICACHE_POLICY_AIVIVT); + set_bit(ICACHEF_AIVIVT, &__icache_flags); + + pr_info("Detected %s I-cache on CPU%d\n", 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(); + info->reg_ctr = read_cpuid_cachetype(); + info->reg_dczid = read_cpuid(DCZID_EL0); + info->reg_midr = read_cpuid_id(); + + info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1); + info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1); + info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1); + info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1); + info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1); + info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1); + + info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1); + info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1); + info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1); + info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1); + info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1); + info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1); + info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1); + info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1); + info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1); + info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1); + info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1); + info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1); + + cpuinfo_detect_icache_policy(info); +} + +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) +{ + struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0); + __cpuinfo_store_cpu(info); + + boot_cpu_data = *info; +} |