arch/arm64/kernel/cpuinfo.c

   1 /*
   2  * Record and handle CPU attributes.
   3  *
   4  * Copyright (C) 2014 ARM Ltd.
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17 #include <asm/arch_timer.h>
  18 #include <asm/cachetype.h>
  19 #include <asm/cpu.h>
  20 #include <asm/cputype.h>
  21 #include <asm/cpufeature.h>
  22
  23 #include <linux/bitops.h>
  24 #include <linux/bug.h>
  25 #include <linux/init.h>
  26 #include <linux/kernel.h>
  27 #include <linux/preempt.h>
  28 #include <linux/printk.h>
  29 #include <linux/smp.h>
  30
  31 /*
  32  * In case the boot CPU is hotpluggable, we record its initial state and
  33  * current state separately. Certain system registers may contain different
  34  * values depending on configuration at or after reset.
  35  */
  36 DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data);
  37 static struct cpuinfo_arm64 boot_cpu_data;
  38 static bool mixed_endian_el0 = true;
  39
  40 static char *icache_policy_str[] = {
  41         [ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN",
  42         [ICACHE_POLICY_AIVIVT] = "AIVIVT",
  43         [ICACHE_POLICY_VIPT] = "VIPT",
  44         [ICACHE_POLICY_PIPT] = "PIPT",
  45 };
  46
  47 unsigned long __icache_flags;
  48
  49 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
  50 {
  51         unsigned int cpu = smp_processor_id();
  52         u32 l1ip = CTR_L1IP(info->reg_ctr);
  53
  54         if (l1ip != ICACHE_POLICY_PIPT) {
  55                 /*
  56                  * VIPT caches are non-aliasing if the VA always equals the PA
  57                  * in all bit positions that are covered by the index. This is
  58                  * the case if the size of a way (# of sets * line size) does
  59                  * not exceed PAGE_SIZE.
  60                  */
  61                 u32 waysize = icache_get_numsets() * icache_get_linesize();
  62
  63                 if (l1ip != ICACHE_POLICY_VIPT || waysize > PAGE_SIZE)
  64                         set_bit(ICACHEF_ALIASING, &__icache_flags);
  65         }
  66         if (l1ip == ICACHE_POLICY_AIVIVT)
  67                 set_bit(ICACHEF_AIVIVT, &__icache_flags);
  68
  69         pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu);
  70 }
  71
  72 bool cpu_supports_mixed_endian_el0(void)
  73 {
  74         return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
  75 }
  76
  77 bool system_supports_mixed_endian_el0(void)
  78 {
  79         return mixed_endian_el0;
  80 }
  81
  82 static void update_mixed_endian_el0_support(struct cpuinfo_arm64 *info)
  83 {
  84         mixed_endian_el0 &= id_aa64mmfr0_mixed_endian_el0(info->reg_id_aa64mmfr0);
  85 }
  86
  87 static void update_cpu_features(struct cpuinfo_arm64 *info)
  88 {
  89         update_mixed_endian_el0_support(info);
  90 }
  91
  92 static int check_reg_mask(char *name, u64 mask, u64 boot, u64 cur, int cpu)
  93 {
  94         if ((boot & mask) == (cur & mask))
  95                 return 0;
  96
  97         pr_warn("SANITY CHECK: Unexpected variation in %s. Boot CPU: %#016lx, CPU%d: %#016lx\n",
  98                 name, (unsigned long)boot, cpu, (unsigned long)cur);
  99
 100         return 1;
 101 }
 102
 103 #define CHECK_MASK(field, mask, boot, cur, cpu) \
 104         check_reg_mask(#field, mask, (boot)->reg_ ## field, (cur)->reg_ ## field, cpu)
 105
 106 #define CHECK(field, boot, cur, cpu) \
 107         CHECK_MASK(field, ~0ULL, boot, cur, cpu)
 108
 109 /*
 110  * Verify that CPUs don't have unexpected differences that will cause problems.
 111  */
 112 static void cpuinfo_sanity_check(struct cpuinfo_arm64 *cur)
 113 {
 114         unsigned int cpu = smp_processor_id();
 115         struct cpuinfo_arm64 *boot = &boot_cpu_data;
 116         unsigned int diff = 0;
 117
 118         /*
 119          * The kernel can handle differing I-cache policies, but otherwise
 120          * caches should look identical. Userspace JITs will make use of
 121          * *minLine.
 122          */
 123         diff |= CHECK_MASK(ctr, 0xffff3fff, boot, cur, cpu);
 124
 125         /*
 126          * Userspace may perform DC ZVA instructions. Mismatched block sizes
 127          * could result in too much or too little memory being zeroed if a
 128          * process is preempted and migrated between CPUs.
 129          */
 130         diff |= CHECK(dczid, boot, cur, cpu);
 131
 132         /* If different, timekeeping will be broken (especially with KVM) */
 133         diff |= CHECK(cntfrq, boot, cur, cpu);
 134
 135         /*
 136          * The kernel uses self-hosted debug features and expects CPUs to
 137          * support identical debug features. We presently need CTX_CMPs, WRPs,
 138          * and BRPs to be identical.
 139          * ID_AA64DFR1 is currently RES0.
 140          */
 141         diff |= CHECK(id_aa64dfr0, boot, cur, cpu);
 142         diff |= CHECK(id_aa64dfr1, boot, cur, cpu);
 143
 144         /*
 145          * Even in big.LITTLE, processors should be identical instruction-set
 146          * wise.
 147          */
 148         diff |= CHECK(id_aa64isar0, boot, cur, cpu);
 149         diff |= CHECK(id_aa64isar1, boot, cur, cpu);
 150
 151         /*
 152          * Differing PARange support is fine as long as all peripherals and
 153          * memory are mapped within the minimum PARange of all CPUs.
 154          * Linux should not care about secure memory.
 155          * ID_AA64MMFR1 is currently RES0.
 156          */
 157         diff |= CHECK_MASK(id_aa64mmfr0, 0xffffffffffff0ff0, boot, cur, cpu);
 158         diff |= CHECK(id_aa64mmfr1, boot, cur, cpu);
 159
 160         /*
 161          * EL3 is not our concern.
 162          * ID_AA64PFR1 is currently RES0.
 163          */
 164         diff |= CHECK_MASK(id_aa64pfr0, 0xffffffffffff0fff, boot, cur, cpu);
 165         diff |= CHECK(id_aa64pfr1, boot, cur, cpu);
 166
 167         /*
 168          * If we have AArch32, we care about 32-bit features for compat. These
 169          * registers should be RES0 otherwise.
 170          */
 171         diff |= CHECK(id_dfr0, boot, cur, cpu);
 172         diff |= CHECK(id_isar0, boot, cur, cpu);
 173         diff |= CHECK(id_isar1, boot, cur, cpu);
 174         diff |= CHECK(id_isar2, boot, cur, cpu);
 175         diff |= CHECK(id_isar3, boot, cur, cpu);
 176         diff |= CHECK(id_isar4, boot, cur, cpu);
 177         diff |= CHECK(id_isar5, boot, cur, cpu);
 178         /*
 179          * Regardless of the value of the AuxReg field, the AIFSR, ADFSR, and
 180          * ACTLR formats could differ across CPUs and therefore would have to
 181          * be trapped for virtualization anyway.
 182          */
 183         diff |= CHECK_MASK(id_mmfr0, 0xff0fffff, boot, cur, cpu);
 184         diff |= CHECK(id_mmfr1, boot, cur, cpu);
 185         diff |= CHECK(id_mmfr2, boot, cur, cpu);
 186         diff |= CHECK(id_mmfr3, boot, cur, cpu);
 187         diff |= CHECK(id_pfr0, boot, cur, cpu);
 188         diff |= CHECK(id_pfr1, boot, cur, cpu);
 189
 190         diff |= CHECK(mvfr0, boot, cur, cpu);
 191         diff |= CHECK(mvfr1, boot, cur, cpu);
 192         diff |= CHECK(mvfr2, boot, cur, cpu);
 193
 194         /*
 195          * Mismatched CPU features are a recipe for disaster. Don't even
 196          * pretend to support them.
 197          */
 198         WARN_TAINT_ONCE(diff, TAINT_CPU_OUT_OF_SPEC,
 199                         "Unsupported CPU feature variation.\n");
 200 }
 201
 202 static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 203 {
 204         info->reg_cntfrq = arch_timer_get_cntfrq();
 205         info->reg_ctr = read_cpuid_cachetype();
 206         info->reg_dczid = read_cpuid(DCZID_EL0);
 207         info->reg_midr = read_cpuid_id();
 208
 209         info->reg_id_aa64dfr0 = read_cpuid(ID_AA64DFR0_EL1);
 210         info->reg_id_aa64dfr1 = read_cpuid(ID_AA64DFR1_EL1);
 211         info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
 212         info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
 213         info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
 214         info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
 215         info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
 216         info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
 217
 218         info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
 219         info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
 220         info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
 221         info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
 222         info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
 223         info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
 224         info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
 225         info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
 226         info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
 227         info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
 228         info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1);
 229         info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
 230         info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
 231
 232         info->reg_mvfr0 = read_cpuid(MVFR0_EL1);
 233         info->reg_mvfr1 = read_cpuid(MVFR1_EL1);
 234         info->reg_mvfr2 = read_cpuid(MVFR2_EL1);
 235
 236         cpuinfo_detect_icache_policy(info);
 237
 238         check_local_cpu_errata();
 239         check_local_cpu_features();
 240         update_cpu_features(info);
 241 }
 242
 243 void cpuinfo_store_cpu(void)
 244 {
 245         struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
 246         __cpuinfo_store_cpu(info);
 247         cpuinfo_sanity_check(info);
 248 }
 249
 250 void __init cpuinfo_store_boot_cpu(void)
 251 {
 252         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
 253         __cpuinfo_store_cpu(info);
 254
 255         boot_cpu_data = *info;
 256 }