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