arch/arm64/kernel/cpuinfo.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Record and handle CPU attributes.
   4  *
   5  * Copyright (C) 2014 ARM Ltd.
   6  */
   7 #include <asm/arch_timer.h>
   8 #include <asm/cache.h>
   9 #include <asm/cpu.h>
  10 #include <asm/cputype.h>
  11 #include <asm/cpufeature.h>
  12 #include <asm/fpsimd.h>
  13
  14 #include <linux/bitops.h>
  15 #include <linux/bug.h>
  16 #include <linux/compat.h>
  17 #include <linux/elf.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/personality.h>
  21 #include <linux/preempt.h>
  22 #include <linux/printk.h>
  23 #include <linux/seq_file.h>
  24 #include <linux/sched.h>
  25 #include <linux/smp.h>
  26 #include <linux/delay.h>
  27
  28 /*
  29  * In case the boot CPU is hotpluggable, we record its initial state and
  30  * current state separately. Certain system registers may contain different
  31  * values depending on configuration at or after reset.
  32  */
  33 DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data);
  34 static struct cpuinfo_arm64 boot_cpu_data;
  35
  36 static char *icache_policy_str[] = {
  37         [0 ... ICACHE_POLICY_PIPT]      = "RESERVED/UNKNOWN",
  38         [ICACHE_POLICY_VIPT]            = "VIPT",
  39         [ICACHE_POLICY_PIPT]            = "PIPT",
  40         [ICACHE_POLICY_VPIPT]           = "VPIPT",
  41 };
  42
  43 unsigned long __icache_flags;
  44
  45 static const char *const hwcap_str[] = {
  46         "fp",
  47         "asimd",
  48         "evtstrm",
  49         "aes",
  50         "pmull",
  51         "sha1",
  52         "sha2",
  53         "crc32",
  54         "atomics",
  55         "fphp",
  56         "asimdhp",
  57         "cpuid",
  58         "asimdrdm",
  59         "jscvt",
  60         "fcma",
  61         "lrcpc",
  62         "dcpop",
  63         "sha3",
  64         "sm3",
  65         "sm4",
  66         "asimddp",
  67         "sha512",
  68         "sve",
  69         "asimdfhm",
  70         "dit",
  71         "uscat",
  72         "ilrcpc",
  73         "flagm",
  74         "ssbs",
  75         "sb",
  76         "paca",
  77         "pacg",
  78         "dcpodp",
  79         "sve2",
  80         "sveaes",
  81         "svepmull",
  82         "svebitperm",
  83         "svesha3",
  84         "svesm4",
  85         NULL
  86 };
  87
  88 #ifdef CONFIG_COMPAT
  89 static const char *const compat_hwcap_str[] = {
  90         "swp",
  91         "half",
  92         "thumb",
  93         "26bit",
  94         "fastmult",
  95         "fpa",
  96         "vfp",
  97         "edsp",
  98         "java",
  99         "iwmmxt",
 100         "crunch",
 101         "thumbee",
 102         "neon",
 103         "vfpv3",
 104         "vfpv3d16",
 105         "tls",
 106         "vfpv4",
 107         "idiva",
 108         "idivt",
 109         "vfpd32",
 110         "lpae",
 111         "evtstrm",
 112         NULL
 113 };
 114
 115 static const char *const compat_hwcap2_str[] = {
 116         "aes",
 117         "pmull",
 118         "sha1",
 119         "sha2",
 120         "crc32",
 121         NULL
 122 };
 123 #endif /* CONFIG_COMPAT */
 124
 125 static int c_show(struct seq_file *m, void *v)
 126 {
 127         int i, j;
 128         bool compat = personality(current->personality) == PER_LINUX32;
 129
 130         for_each_online_cpu(i) {
 131                 struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i);
 132                 u32 midr = cpuinfo->reg_midr;
 133
 134                 /*
 135                  * glibc reads /proc/cpuinfo to determine the number of
 136                  * online processors, looking for lines beginning with
 137                  * "processor".  Give glibc what it expects.
 138                  */
 139                 seq_printf(m, "processor\t: %d\n", i);
 140                 if (compat)
 141                         seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n",
 142                                    MIDR_REVISION(midr), COMPAT_ELF_PLATFORM);
 143
 144                 seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
 145                            loops_per_jiffy / (500000UL/HZ),
 146                            loops_per_jiffy / (5000UL/HZ) % 100);
 147
 148                 /*
 149                  * Dump out the common processor features in a single line.
 150                  * Userspace should read the hwcaps with getauxval(AT_HWCAP)
 151                  * rather than attempting to parse this, but there's a body of
 152                  * software which does already (at least for 32-bit).
 153                  */
 154                 seq_puts(m, "Features\t:");
 155                 if (compat) {
 156 #ifdef CONFIG_COMPAT
 157                         for (j = 0; compat_hwcap_str[j]; j++)
 158                                 if (compat_elf_hwcap & (1 << j))
 159                                         seq_printf(m, " %s", compat_hwcap_str[j]);
 160
 161                         for (j = 0; compat_hwcap2_str[j]; j++)
 162                                 if (compat_elf_hwcap2 & (1 << j))
 163                                         seq_printf(m, " %s", compat_hwcap2_str[j]);
 164 #endif /* CONFIG_COMPAT */
 165                 } else {
 166                         for (j = 0; hwcap_str[j]; j++)
 167                                 if (cpu_have_feature(j))
 168                                         seq_printf(m, " %s", hwcap_str[j]);
 169                 }
 170                 seq_puts(m, "\n");
 171
 172                 seq_printf(m, "CPU implementer\t: 0x%02x\n",
 173                            MIDR_IMPLEMENTOR(midr));
 174                 seq_printf(m, "CPU architecture: 8\n");
 175                 seq_printf(m, "CPU variant\t: 0x%x\n", MIDR_VARIANT(midr));
 176                 seq_printf(m, "CPU part\t: 0x%03x\n", MIDR_PARTNUM(midr));
 177                 seq_printf(m, "CPU revision\t: %d\n\n", MIDR_REVISION(midr));
 178         }
 179
 180         return 0;
 181 }
 182
 183 static void *c_start(struct seq_file *m, loff_t *pos)
 184 {
 185         return *pos < 1 ? (void *)1 : NULL;
 186 }
 187
 188 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 189 {
 190         ++*pos;
 191         return NULL;
 192 }
 193
 194 static void c_stop(struct seq_file *m, void *v)
 195 {
 196 }
 197
 198 const struct seq_operations cpuinfo_op = {
 199         .start  = c_start,
 200         .next   = c_next,
 201         .stop   = c_stop,
 202         .show   = c_show
 203 };
 204
 205
 206 static struct kobj_type cpuregs_kobj_type = {
 207         .sysfs_ops = &kobj_sysfs_ops,
 208 };
 209
 210 /*
 211  * The ARM ARM uses the phrase "32-bit register" to describe a register
 212  * whose upper 32 bits are RES0 (per C5.1.1, ARM DDI 0487A.i), however
 213  * no statement is made as to whether the upper 32 bits will or will not
 214  * be made use of in future, and between ARM DDI 0487A.c and ARM DDI
 215  * 0487A.d CLIDR_EL1 was expanded from 32-bit to 64-bit.
 216  *
 217  * Thus, while both MIDR_EL1 and REVIDR_EL1 are described as 32-bit
 218  * registers, we expose them both as 64 bit values to cater for possible
 219  * future expansion without an ABI break.
 220  */
 221 #define kobj_to_cpuinfo(kobj)   container_of(kobj, struct cpuinfo_arm64, kobj)
 222 #define CPUREGS_ATTR_RO(_name, _field)                                          \
 223         static ssize_t _name##_show(struct kobject *kobj,                       \
 224                         struct kobj_attribute *attr, char *buf)                 \
 225         {                                                                       \
 226                 struct cpuinfo_arm64 *info = kobj_to_cpuinfo(kobj);             \
 227                                                                                 \
 228                 if (info->reg_midr)                                             \
 229                         return sprintf(buf, "0x%016x\n", info->reg_##_field);   \
 230                 else                                                            \
 231                         return 0;                                               \
 232         }                                                                       \
 233         static struct kobj_attribute cpuregs_attr_##_name = __ATTR_RO(_name)
 234
 235 CPUREGS_ATTR_RO(midr_el1, midr);
 236 CPUREGS_ATTR_RO(revidr_el1, revidr);
 237
 238 static struct attribute *cpuregs_id_attrs[] = {
 239         &cpuregs_attr_midr_el1.attr,
 240         &cpuregs_attr_revidr_el1.attr,
 241         NULL
 242 };
 243
 244 static const struct attribute_group cpuregs_attr_group = {
 245         .attrs = cpuregs_id_attrs,
 246         .name = "identification"
 247 };
 248
 249 static int cpuid_cpu_online(unsigned int cpu)
 250 {
 251         int rc;
 252         struct device *dev;
 253         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 254
 255         dev = get_cpu_device(cpu);
 256         if (!dev) {
 257                 rc = -ENODEV;
 258                 goto out;
 259         }
 260         rc = kobject_add(&info->kobj, &dev->kobj, "regs");
 261         if (rc)
 262                 goto out;
 263         rc = sysfs_create_group(&info->kobj, &cpuregs_attr_group);
 264         if (rc)
 265                 kobject_del(&info->kobj);
 266 out:
 267         return rc;
 268 }
 269
 270 static int cpuid_cpu_offline(unsigned int cpu)
 271 {
 272         struct device *dev;
 273         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 274
 275         dev = get_cpu_device(cpu);
 276         if (!dev)
 277                 return -ENODEV;
 278         if (info->kobj.parent) {
 279                 sysfs_remove_group(&info->kobj, &cpuregs_attr_group);
 280                 kobject_del(&info->kobj);
 281         }
 282
 283         return 0;
 284 }
 285
 286 static int __init cpuinfo_regs_init(void)
 287 {
 288         int cpu, ret;
 289
 290         for_each_possible_cpu(cpu) {
 291                 struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 292
 293                 kobject_init(&info->kobj, &cpuregs_kobj_type);
 294         }
 295
 296         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/cpuinfo:online",
 297                                 cpuid_cpu_online, cpuid_cpu_offline);
 298         if (ret < 0) {
 299                 pr_err("cpuinfo: failed to register hotplug callbacks.\n");
 300                 return ret;
 301         }
 302         return 0;
 303 }
 304 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
 305 {
 306         unsigned int cpu = smp_processor_id();
 307         u32 l1ip = CTR_L1IP(info->reg_ctr);
 308
 309         switch (l1ip) {
 310         case ICACHE_POLICY_PIPT:
 311                 break;
 312         case ICACHE_POLICY_VPIPT:
 313                 set_bit(ICACHEF_VPIPT, &__icache_flags);
 314                 break;
 315         default:
 316                 /* Fallthrough */
 317         case ICACHE_POLICY_VIPT:
 318                 /* Assume aliasing */
 319                 set_bit(ICACHEF_ALIASING, &__icache_flags);
 320         }
 321
 322         pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu);
 323 }
 324
 325 static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 326 {
 327         info->reg_cntfrq = arch_timer_get_cntfrq();
 328         /*
 329          * Use the effective value of the CTR_EL0 than the raw value
 330          * exposed by the CPU. CTR_E0.IDC field value must be interpreted
 331          * with the CLIDR_EL1 fields to avoid triggering false warnings
 332          * when there is a mismatch across the CPUs. Keep track of the
 333          * effective value of the CTR_EL0 in our internal records for
 334          * acurate sanity check and feature enablement.
 335          */
 336         info->reg_ctr = read_cpuid_effective_cachetype();
 337         info->reg_dczid = read_cpuid(DCZID_EL0);
 338         info->reg_midr = read_cpuid_id();
 339         info->reg_revidr = read_cpuid(REVIDR_EL1);
 340
 341         info->reg_id_aa64dfr0 = read_cpuid(ID_AA64DFR0_EL1);
 342         info->reg_id_aa64dfr1 = read_cpuid(ID_AA64DFR1_EL1);
 343         info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
 344         info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
 345         info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
 346         info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
 347         info->reg_id_aa64mmfr2 = read_cpuid(ID_AA64MMFR2_EL1);
 348         info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
 349         info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
 350         info->reg_id_aa64zfr0 = read_cpuid(ID_AA64ZFR0_EL1);
 351
 352         /* Update the 32bit ID registers only if AArch32 is implemented */
 353         if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
 354                 info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
 355                 info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
 356                 info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
 357                 info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
 358                 info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
 359                 info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
 360                 info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
 361                 info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
 362                 info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
 363                 info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
 364                 info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1);
 365                 info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
 366                 info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
 367
 368                 info->reg_mvfr0 = read_cpuid(MVFR0_EL1);
 369                 info->reg_mvfr1 = read_cpuid(MVFR1_EL1);
 370                 info->reg_mvfr2 = read_cpuid(MVFR2_EL1);
 371         }
 372
 373         if (IS_ENABLED(CONFIG_ARM64_SVE) &&
 374             id_aa64pfr0_sve(info->reg_id_aa64pfr0))
 375                 info->reg_zcr = read_zcr_features();
 376
 377         cpuinfo_detect_icache_policy(info);
 378 }
 379
 380 void cpuinfo_store_cpu(void)
 381 {
 382         struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
 383         __cpuinfo_store_cpu(info);
 384         update_cpu_features(smp_processor_id(), info, &boot_cpu_data);
 385 }
 386
 387 void __init cpuinfo_store_boot_cpu(void)
 388 {
 389         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
 390         __cpuinfo_store_cpu(info);
 391
 392         boot_cpu_data = *info;
 393         init_cpu_features(&boot_cpu_data);
 394 }
 395
 396 device_initcall(cpuinfo_regs_init);