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         "dit",
  81         "uscat",
  82         "ilrcpc",
  83         "flagm",
  84         "ssbs",
  85         "sb",
  86         "paca",
  87         "pacg",
  88         "dcpodp",
  89         "sve2",
  90         "sveaes",
  91         "svepmull",
  92         "svebitperm",
  93         "svesha3",
  94         "svesm4",
  95         NULL
  96 };
  97
  98 #ifdef CONFIG_COMPAT
  99 static const char *const compat_hwcap_str[] = {
 100         "swp",
 101         "half",
 102         "thumb",
 103         "26bit",
 104         "fastmult",
 105         "fpa",
 106         "vfp",
 107         "edsp",
 108         "java",
 109         "iwmmxt",
 110         "crunch",
 111         "thumbee",
 112         "neon",
 113         "vfpv3",
 114         "vfpv3d16",
 115         "tls",
 116         "vfpv4",
 117         "idiva",
 118         "idivt",
 119         "vfpd32",
 120         "lpae",
 121         "evtstrm",
 122         NULL
 123 };
 124
 125 static const char *const compat_hwcap2_str[] = {
 126         "aes",
 127         "pmull",
 128         "sha1",
 129         "sha2",
 130         "crc32",
 131         NULL
 132 };
 133 #endif /* CONFIG_COMPAT */
 134
 135 static int c_show(struct seq_file *m, void *v)
 136 {
 137         int i, j;
 138         bool compat = personality(current->personality) == PER_LINUX32;
 139
 140         for_each_online_cpu(i) {
 141                 struct cpuinfo_arm64 *cpuinfo = &per_cpu(cpu_data, i);
 142                 u32 midr = cpuinfo->reg_midr;
 143
 144                 /*
 145                  * glibc reads /proc/cpuinfo to determine the number of
 146                  * online processors, looking for lines beginning with
 147                  * "processor".  Give glibc what it expects.
 148                  */
 149                 seq_printf(m, "processor\t: %d\n", i);
 150                 if (compat)
 151                         seq_printf(m, "model name\t: ARMv8 Processor rev %d (%s)\n",
 152                                    MIDR_REVISION(midr), COMPAT_ELF_PLATFORM);
 153
 154                 seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
 155                            loops_per_jiffy / (500000UL/HZ),
 156                            loops_per_jiffy / (5000UL/HZ) % 100);
 157
 158                 /*
 159                  * Dump out the common processor features in a single line.
 160                  * Userspace should read the hwcaps with getauxval(AT_HWCAP)
 161                  * rather than attempting to parse this, but there's a body of
 162                  * software which does already (at least for 32-bit).
 163                  */
 164                 seq_puts(m, "Features\t:");
 165                 if (compat) {
 166 #ifdef CONFIG_COMPAT
 167                         for (j = 0; compat_hwcap_str[j]; j++)
 168                                 if (compat_elf_hwcap & (1 << j))
 169                                         seq_printf(m, " %s", compat_hwcap_str[j]);
 170
 171                         for (j = 0; compat_hwcap2_str[j]; j++)
 172                                 if (compat_elf_hwcap2 & (1 << j))
 173                                         seq_printf(m, " %s", compat_hwcap2_str[j]);
 174 #endif /* CONFIG_COMPAT */
 175                 } else {
 176                         for (j = 0; hwcap_str[j]; j++)
 177                                 if (cpu_have_feature(j))
 178                                         seq_printf(m, " %s", hwcap_str[j]);
 179                 }
 180                 seq_puts(m, "\n");
 181
 182                 seq_printf(m, "CPU implementer\t: 0x%02x\n",
 183                            MIDR_IMPLEMENTOR(midr));
 184                 seq_printf(m, "CPU architecture: 8\n");
 185                 seq_printf(m, "CPU variant\t: 0x%x\n", MIDR_VARIANT(midr));
 186                 seq_printf(m, "CPU part\t: 0x%03x\n", MIDR_PARTNUM(midr));
 187                 seq_printf(m, "CPU revision\t: %d\n\n", MIDR_REVISION(midr));
 188         }
 189
 190         return 0;
 191 }
 192
 193 static void *c_start(struct seq_file *m, loff_t *pos)
 194 {
 195         return *pos < 1 ? (void *)1 : NULL;
 196 }
 197
 198 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 199 {
 200         ++*pos;
 201         return NULL;
 202 }
 203
 204 static void c_stop(struct seq_file *m, void *v)
 205 {
 206 }
 207
 208 const struct seq_operations cpuinfo_op = {
 209         .start  = c_start,
 210         .next   = c_next,
 211         .stop   = c_stop,
 212         .show   = c_show
 213 };
 214
 215
 216 static struct kobj_type cpuregs_kobj_type = {
 217         .sysfs_ops = &kobj_sysfs_ops,
 218 };
 219
 220 /*
 221  * The ARM ARM uses the phrase "32-bit register" to describe a register
 222  * whose upper 32 bits are RES0 (per C5.1.1, ARM DDI 0487A.i), however
 223  * no statement is made as to whether the upper 32 bits will or will not
 224  * be made use of in future, and between ARM DDI 0487A.c and ARM DDI
 225  * 0487A.d CLIDR_EL1 was expanded from 32-bit to 64-bit.
 226  *
 227  * Thus, while both MIDR_EL1 and REVIDR_EL1 are described as 32-bit
 228  * registers, we expose them both as 64 bit values to cater for possible
 229  * future expansion without an ABI break.
 230  */
 231 #define kobj_to_cpuinfo(kobj)   container_of(kobj, struct cpuinfo_arm64, kobj)
 232 #define CPUREGS_ATTR_RO(_name, _field)                                          \
 233         static ssize_t _name##_show(struct kobject *kobj,                       \
 234                         struct kobj_attribute *attr, char *buf)                 \
 235         {                                                                       \
 236                 struct cpuinfo_arm64 *info = kobj_to_cpuinfo(kobj);             \
 237                                                                                 \
 238                 if (info->reg_midr)                                             \
 239                         return sprintf(buf, "0x%016x\n", info->reg_##_field);   \
 240                 else                                                            \
 241                         return 0;                                               \
 242         }                                                                       \
 243         static struct kobj_attribute cpuregs_attr_##_name = __ATTR_RO(_name)
 244
 245 CPUREGS_ATTR_RO(midr_el1, midr);
 246 CPUREGS_ATTR_RO(revidr_el1, revidr);
 247
 248 static struct attribute *cpuregs_id_attrs[] = {
 249         &cpuregs_attr_midr_el1.attr,
 250         &cpuregs_attr_revidr_el1.attr,
 251         NULL
 252 };
 253
 254 static const struct attribute_group cpuregs_attr_group = {
 255         .attrs = cpuregs_id_attrs,
 256         .name = "identification"
 257 };
 258
 259 static int cpuid_cpu_online(unsigned int cpu)
 260 {
 261         int rc;
 262         struct device *dev;
 263         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 264
 265         dev = get_cpu_device(cpu);
 266         if (!dev) {
 267                 rc = -ENODEV;
 268                 goto out;
 269         }
 270         rc = kobject_add(&info->kobj, &dev->kobj, "regs");
 271         if (rc)
 272                 goto out;
 273         rc = sysfs_create_group(&info->kobj, &cpuregs_attr_group);
 274         if (rc)
 275                 kobject_del(&info->kobj);
 276 out:
 277         return rc;
 278 }
 279
 280 static int cpuid_cpu_offline(unsigned int cpu)
 281 {
 282         struct device *dev;
 283         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 284
 285         dev = get_cpu_device(cpu);
 286         if (!dev)
 287                 return -ENODEV;
 288         if (info->kobj.parent) {
 289                 sysfs_remove_group(&info->kobj, &cpuregs_attr_group);
 290                 kobject_del(&info->kobj);
 291         }
 292
 293         return 0;
 294 }
 295
 296 static int __init cpuinfo_regs_init(void)
 297 {
 298         int cpu, ret;
 299
 300         for_each_possible_cpu(cpu) {
 301                 struct cpuinfo_arm64 *info = &per_cpu(cpu_data, cpu);
 302
 303                 kobject_init(&info->kobj, &cpuregs_kobj_type);
 304         }
 305
 306         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "arm64/cpuinfo:online",
 307                                 cpuid_cpu_online, cpuid_cpu_offline);
 308         if (ret < 0) {
 309                 pr_err("cpuinfo: failed to register hotplug callbacks.\n");
 310                 return ret;
 311         }
 312         return 0;
 313 }
 314 static void cpuinfo_detect_icache_policy(struct cpuinfo_arm64 *info)
 315 {
 316         unsigned int cpu = smp_processor_id();
 317         u32 l1ip = CTR_L1IP(info->reg_ctr);
 318
 319         switch (l1ip) {
 320         case ICACHE_POLICY_PIPT:
 321                 break;
 322         case ICACHE_POLICY_VPIPT:
 323                 set_bit(ICACHEF_VPIPT, &__icache_flags);
 324                 break;
 325         default:
 326                 /* Fallthrough */
 327         case ICACHE_POLICY_VIPT:
 328                 /* Assume aliasing */
 329                 set_bit(ICACHEF_ALIASING, &__icache_flags);
 330         }
 331
 332         pr_info("Detected %s I-cache on CPU%d\n", icache_policy_str[l1ip], cpu);
 333 }
 334
 335 static void __cpuinfo_store_cpu(struct cpuinfo_arm64 *info)
 336 {
 337         info->reg_cntfrq = arch_timer_get_cntfrq();
 338         /*
 339          * Use the effective value of the CTR_EL0 than the raw value
 340          * exposed by the CPU. CTR_E0.IDC field value must be interpreted
 341          * with the CLIDR_EL1 fields to avoid triggering false warnings
 342          * when there is a mismatch across the CPUs. Keep track of the
 343          * effective value of the CTR_EL0 in our internal records for
 344          * acurate sanity check and feature enablement.
 345          */
 346         info->reg_ctr = read_cpuid_effective_cachetype();
 347         info->reg_dczid = read_cpuid(DCZID_EL0);
 348         info->reg_midr = read_cpuid_id();
 349         info->reg_revidr = read_cpuid(REVIDR_EL1);
 350
 351         info->reg_id_aa64dfr0 = read_cpuid(ID_AA64DFR0_EL1);
 352         info->reg_id_aa64dfr1 = read_cpuid(ID_AA64DFR1_EL1);
 353         info->reg_id_aa64isar0 = read_cpuid(ID_AA64ISAR0_EL1);
 354         info->reg_id_aa64isar1 = read_cpuid(ID_AA64ISAR1_EL1);
 355         info->reg_id_aa64mmfr0 = read_cpuid(ID_AA64MMFR0_EL1);
 356         info->reg_id_aa64mmfr1 = read_cpuid(ID_AA64MMFR1_EL1);
 357         info->reg_id_aa64mmfr2 = read_cpuid(ID_AA64MMFR2_EL1);
 358         info->reg_id_aa64pfr0 = read_cpuid(ID_AA64PFR0_EL1);
 359         info->reg_id_aa64pfr1 = read_cpuid(ID_AA64PFR1_EL1);
 360         info->reg_id_aa64zfr0 = read_cpuid(ID_AA64ZFR0_EL1);
 361
 362         /* Update the 32bit ID registers only if AArch32 is implemented */
 363         if (id_aa64pfr0_32bit_el0(info->reg_id_aa64pfr0)) {
 364                 info->reg_id_dfr0 = read_cpuid(ID_DFR0_EL1);
 365                 info->reg_id_isar0 = read_cpuid(ID_ISAR0_EL1);
 366                 info->reg_id_isar1 = read_cpuid(ID_ISAR1_EL1);
 367                 info->reg_id_isar2 = read_cpuid(ID_ISAR2_EL1);
 368                 info->reg_id_isar3 = read_cpuid(ID_ISAR3_EL1);
 369                 info->reg_id_isar4 = read_cpuid(ID_ISAR4_EL1);
 370                 info->reg_id_isar5 = read_cpuid(ID_ISAR5_EL1);
 371                 info->reg_id_mmfr0 = read_cpuid(ID_MMFR0_EL1);
 372                 info->reg_id_mmfr1 = read_cpuid(ID_MMFR1_EL1);
 373                 info->reg_id_mmfr2 = read_cpuid(ID_MMFR2_EL1);
 374                 info->reg_id_mmfr3 = read_cpuid(ID_MMFR3_EL1);
 375                 info->reg_id_pfr0 = read_cpuid(ID_PFR0_EL1);
 376                 info->reg_id_pfr1 = read_cpuid(ID_PFR1_EL1);
 377
 378                 info->reg_mvfr0 = read_cpuid(MVFR0_EL1);
 379                 info->reg_mvfr1 = read_cpuid(MVFR1_EL1);
 380                 info->reg_mvfr2 = read_cpuid(MVFR2_EL1);
 381         }
 382
 383         if (IS_ENABLED(CONFIG_ARM64_SVE) &&
 384             id_aa64pfr0_sve(info->reg_id_aa64pfr0))
 385                 info->reg_zcr = read_zcr_features();
 386
 387         cpuinfo_detect_icache_policy(info);
 388 }
 389
 390 void cpuinfo_store_cpu(void)
 391 {
 392         struct cpuinfo_arm64 *info = this_cpu_ptr(&cpu_data);
 393         __cpuinfo_store_cpu(info);
 394         update_cpu_features(smp_processor_id(), info, &boot_cpu_data);
 395 }
 396
 397 void __init cpuinfo_store_boot_cpu(void)
 398 {
 399         struct cpuinfo_arm64 *info = &per_cpu(cpu_data, 0);
 400         __cpuinfo_store_cpu(info);
 401
 402         boot_cpu_data = *info;
 403         init_cpu_features(&boot_cpu_data);
 404 }
 405
 406 device_initcall(cpuinfo_regs_init);