drivers/base/cpu.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * CPU subsystem support
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/sched.h>
  10 #include <linux/cpu.h>
  11 #include <linux/topology.h>
  12 #include <linux/device.h>
  13 #include <linux/node.h>
  14 #include <linux/gfp.h>
  15 #include <linux/slab.h>
  16 #include <linux/percpu.h>
  17 #include <linux/acpi.h>
  18 #include <linux/of.h>
  19 #include <linux/cpufeature.h>
  20 #include <linux/tick.h>
  21 #include <linux/pm_qos.h>
  22 #include <linux/delay.h>
  23 #include <linux/sched/isolation.h>
  24
  25 #include "base.h"
  26
  27 static DEFINE_PER_CPU(struct device *, cpu_sys_devices);
  28
  29 static int cpu_subsys_match(struct device *dev, struct device_driver *drv)
  30 {
  31         /* ACPI style match is the only one that may succeed. */
  32         if (acpi_driver_match_device(dev, drv))
  33                 return 1;
  34
  35         return 0;
  36 }
  37
  38 #ifdef CONFIG_HOTPLUG_CPU
  39 static void change_cpu_under_node(struct cpu *cpu,
  40                         unsigned int from_nid, unsigned int to_nid)
  41 {
  42         int cpuid = cpu->dev.id;
  43         unregister_cpu_under_node(cpuid, from_nid);
  44         register_cpu_under_node(cpuid, to_nid);
  45         cpu->node_id = to_nid;
  46 }
  47
  48 static int cpu_subsys_online(struct device *dev)
  49 {
  50         struct cpu *cpu = container_of(dev, struct cpu, dev);
  51         int cpuid = dev->id;
  52         int from_nid, to_nid;
  53         int ret;
  54         int retries = 0;
  55
  56         from_nid = cpu_to_node(cpuid);
  57         if (from_nid == NUMA_NO_NODE)
  58                 return -ENODEV;
  59
  60 retry:
  61         ret = cpu_device_up(dev);
  62
  63         /*
  64          * If -EBUSY is returned, it is likely that hotplug is temporarily
  65          * disabled when cpu_hotplug_disable() was called. This condition is
  66          * transient. So we retry after waiting for an exponentially
  67          * increasing delay up to a total of at least 620ms as some PCI
  68          * device initialization can take quite a while.
  69          */
  70         if (ret == -EBUSY) {
  71                 retries++;
  72                 if (retries > 5)
  73                         return ret;
  74                 msleep(10 * (1 << retries));
  75                 goto retry;
  76         }
  77
  78         /*
  79          * When hot adding memory to memoryless node and enabling a cpu
  80          * on the node, node number of the cpu may internally change.
  81          */
  82         to_nid = cpu_to_node(cpuid);
  83         if (from_nid != to_nid)
  84                 change_cpu_under_node(cpu, from_nid, to_nid);
  85
  86         return ret;
  87 }
  88
  89 static int cpu_subsys_offline(struct device *dev)
  90 {
  91         return cpu_device_down(dev);
  92 }
  93
  94 void unregister_cpu(struct cpu *cpu)
  95 {
  96         int logical_cpu = cpu->dev.id;
  97
  98         set_cpu_enabled(logical_cpu, false);
  99         unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));
 100
 101         device_unregister(&cpu->dev);
 102         per_cpu(cpu_sys_devices, logical_cpu) = NULL;
 103         return;
 104 }
 105
 106 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
 107 static ssize_t cpu_probe_store(struct device *dev,
 108                                struct device_attribute *attr,
 109                                const char *buf,
 110                                size_t count)
 111 {
 112         ssize_t cnt;
 113         int ret;
 114
 115         ret = lock_device_hotplug_sysfs();
 116         if (ret)
 117                 return ret;
 118
 119         cnt = arch_cpu_probe(buf, count);
 120
 121         unlock_device_hotplug();
 122         return cnt;
 123 }
 124
 125 static ssize_t cpu_release_store(struct device *dev,
 126                                  struct device_attribute *attr,
 127                                  const char *buf,
 128                                  size_t count)
 129 {
 130         ssize_t cnt;
 131         int ret;
 132
 133         ret = lock_device_hotplug_sysfs();
 134         if (ret)
 135                 return ret;
 136
 137         cnt = arch_cpu_release(buf, count);
 138
 139         unlock_device_hotplug();
 140         return cnt;
 141 }
 142
 143 static DEVICE_ATTR(probe, S_IWUSR, NULL, cpu_probe_store);
 144 static DEVICE_ATTR(release, S_IWUSR, NULL, cpu_release_store);
 145 #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
 146 #endif /* CONFIG_HOTPLUG_CPU */
 147
 148 #ifdef CONFIG_CRASH_DUMP
 149 #include <linux/kexec.h>
 150
 151 static ssize_t crash_notes_show(struct device *dev,
 152                                 struct device_attribute *attr,
 153                                 char *buf)
 154 {
 155         struct cpu *cpu = container_of(dev, struct cpu, dev);
 156         unsigned long long addr;
 157         int cpunum;
 158
 159         cpunum = cpu->dev.id;
 160
 161         /*
 162          * Might be reading other cpu's data based on which cpu read thread
 163          * has been scheduled. But cpu data (memory) is allocated once during
 164          * boot up and this data does not change there after. Hence this
 165          * operation should be safe. No locking required.
 166          */
 167         addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
 168
 169         return sysfs_emit(buf, "%llx\n", addr);
 170 }
 171 static DEVICE_ATTR_ADMIN_RO(crash_notes);
 172
 173 static ssize_t crash_notes_size_show(struct device *dev,
 174                                      struct device_attribute *attr,
 175                                      char *buf)
 176 {
 177         return sysfs_emit(buf, "%zu\n", sizeof(note_buf_t));
 178 }
 179 static DEVICE_ATTR_ADMIN_RO(crash_notes_size);
 180
 181 static struct attribute *crash_note_cpu_attrs[] = {
 182         &dev_attr_crash_notes.attr,
 183         &dev_attr_crash_notes_size.attr,
 184         NULL
 185 };
 186
 187 static const struct attribute_group crash_note_cpu_attr_group = {
 188         .attrs = crash_note_cpu_attrs,
 189 };
 190 #endif
 191
 192 static const struct attribute_group *common_cpu_attr_groups[] = {
 193 #ifdef CONFIG_CRASH_DUMP
 194         &crash_note_cpu_attr_group,
 195 #endif
 196         NULL
 197 };
 198
 199 static const struct attribute_group *hotplugable_cpu_attr_groups[] = {
 200 #ifdef CONFIG_CRASH_DUMP
 201         &crash_note_cpu_attr_group,
 202 #endif
 203         NULL
 204 };
 205
 206 /*
 207  * Print cpu online, possible, present, and system maps
 208  */
 209
 210 struct cpu_attr {
 211         struct device_attribute attr;
 212         const struct cpumask *const map;
 213 };
 214
 215 static ssize_t show_cpus_attr(struct device *dev,
 216                               struct device_attribute *attr,
 217                               char *buf)
 218 {
 219         struct cpu_attr *ca = container_of(attr, struct cpu_attr, attr);
 220
 221         return cpumap_print_to_pagebuf(true, buf, ca->map);
 222 }
 223
 224 #define _CPU_ATTR(name, map) \
 225         { __ATTR(name, 0444, show_cpus_attr, NULL), map }
 226
 227 /* Keep in sync with cpu_subsys_attrs */
 228 static struct cpu_attr cpu_attrs[] = {
 229         _CPU_ATTR(online, &__cpu_online_mask),
 230         _CPU_ATTR(possible, &__cpu_possible_mask),
 231         _CPU_ATTR(present, &__cpu_present_mask),
 232 };
 233
 234 /*
 235  * Print values for NR_CPUS and offlined cpus
 236  */
 237 static ssize_t print_cpus_kernel_max(struct device *dev,
 238                                      struct device_attribute *attr, char *buf)
 239 {
 240         return sysfs_emit(buf, "%d\n", NR_CPUS - 1);
 241 }
 242 static DEVICE_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);
 243
 244 /* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
 245 unsigned int total_cpus;
 246
 247 static ssize_t print_cpus_offline(struct device *dev,
 248                                   struct device_attribute *attr, char *buf)
 249 {
 250         int len = 0;
 251         cpumask_var_t offline;
 252
 253         /* display offline cpus < nr_cpu_ids */
 254         if (!alloc_cpumask_var(&offline, GFP_KERNEL))
 255                 return -ENOMEM;
 256         cpumask_andnot(offline, cpu_possible_mask, cpu_online_mask);
 257         len += sysfs_emit_at(buf, len, "%*pbl", cpumask_pr_args(offline));
 258         free_cpumask_var(offline);
 259
 260         /* display offline cpus >= nr_cpu_ids */
 261         if (total_cpus && nr_cpu_ids < total_cpus) {
 262                 len += sysfs_emit_at(buf, len, ",");
 263
 264                 if (nr_cpu_ids == total_cpus-1)
 265                         len += sysfs_emit_at(buf, len, "%u", nr_cpu_ids);
 266                 else
 267                         len += sysfs_emit_at(buf, len, "%u-%d",
 268                                              nr_cpu_ids, total_cpus - 1);
 269         }
 270
 271         len += sysfs_emit_at(buf, len, "\n");
 272
 273         return len;
 274 }
 275 static DEVICE_ATTR(offline, 0444, print_cpus_offline, NULL);
 276
 277 static ssize_t print_cpus_enabled(struct device *dev,
 278                                   struct device_attribute *attr, char *buf)
 279 {
 280         return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(cpu_enabled_mask));
 281 }
 282 static DEVICE_ATTR(enabled, 0444, print_cpus_enabled, NULL);
 283
 284 static ssize_t print_cpus_isolated(struct device *dev,
 285                                   struct device_attribute *attr, char *buf)
 286 {
 287         int len;
 288         cpumask_var_t isolated;
 289
 290         if (!alloc_cpumask_var(&isolated, GFP_KERNEL))
 291                 return -ENOMEM;
 292
 293         cpumask_andnot(isolated, cpu_possible_mask,
 294                        housekeeping_cpumask(HK_TYPE_DOMAIN));
 295         len = sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(isolated));
 296
 297         free_cpumask_var(isolated);
 298
 299         return len;
 300 }
 301 static DEVICE_ATTR(isolated, 0444, print_cpus_isolated, NULL);
 302
 303 #ifdef CONFIG_NO_HZ_FULL
 304 static ssize_t print_cpus_nohz_full(struct device *dev,
 305                                     struct device_attribute *attr, char *buf)
 306 {
 307         return sysfs_emit(buf, "%*pbl\n", cpumask_pr_args(tick_nohz_full_mask));
 308 }
 309 static DEVICE_ATTR(nohz_full, 0444, print_cpus_nohz_full, NULL);
 310 #endif
 311
 312 #ifdef CONFIG_CRASH_HOTPLUG
 313 static ssize_t crash_hotplug_show(struct device *dev,
 314                                      struct device_attribute *attr,
 315                                      char *buf)
 316 {
 317         return sysfs_emit(buf, "%d\n", crash_check_hotplug_support());
 318 }
 319 static DEVICE_ATTR_ADMIN_RO(crash_hotplug);
 320 #endif
 321
 322 static void cpu_device_release(struct device *dev)
 323 {
 324         /*
 325          * This is an empty function to prevent the driver core from spitting a
 326          * warning at us.  Yes, I know this is directly opposite of what the
 327          * documentation for the driver core and kobjects say, and the author
 328          * of this code has already been publically ridiculed for doing
 329          * something as foolish as this.  However, at this point in time, it is
 330          * the only way to handle the issue of statically allocated cpu
 331          * devices.  The different architectures will have their cpu device
 332          * code reworked to properly handle this in the near future, so this
 333          * function will then be changed to correctly free up the memory held
 334          * by the cpu device.
 335          *
 336          * Never copy this way of doing things, or you too will be made fun of
 337          * on the linux-kernel list, you have been warned.
 338          */
 339 }
 340
 341 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 342 static ssize_t print_cpu_modalias(struct device *dev,
 343                                   struct device_attribute *attr,
 344                                   char *buf)
 345 {
 346         int len = 0;
 347         u32 i;
 348
 349         len += sysfs_emit_at(buf, len,
 350                              "cpu:type:" CPU_FEATURE_TYPEFMT ":feature:",
 351                              CPU_FEATURE_TYPEVAL);
 352
 353         for (i = 0; i < MAX_CPU_FEATURES; i++)
 354                 if (cpu_have_feature(i)) {
 355                         if (len + sizeof(",XXXX\n") >= PAGE_SIZE) {
 356                                 WARN(1, "CPU features overflow page\n");
 357                                 break;
 358                         }
 359                         len += sysfs_emit_at(buf, len, ",%04X", i);
 360                 }
 361         len += sysfs_emit_at(buf, len, "\n");
 362         return len;
 363 }
 364
 365 static int cpu_uevent(const struct device *dev, struct kobj_uevent_env *env)
 366 {
 367         char *buf = kzalloc(PAGE_SIZE, GFP_KERNEL);
 368         if (buf) {
 369                 print_cpu_modalias(NULL, NULL, buf);
 370                 add_uevent_var(env, "MODALIAS=%s", buf);
 371                 kfree(buf);
 372         }
 373         return 0;
 374 }
 375 #endif
 376
 377 const struct bus_type cpu_subsys = {
 378         .name = "cpu",
 379         .dev_name = "cpu",
 380         .match = cpu_subsys_match,
 381 #ifdef CONFIG_HOTPLUG_CPU
 382         .online = cpu_subsys_online,
 383         .offline = cpu_subsys_offline,
 384 #endif
 385 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 386         .uevent = cpu_uevent,
 387 #endif
 388 };
 389 EXPORT_SYMBOL_GPL(cpu_subsys);
 390
 391 /*
 392  * register_cpu - Setup a sysfs device for a CPU.
 393  * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
 394  *        sysfs for this CPU.
 395  * @num - CPU number to use when creating the device.
 396  *
 397  * Initialize and register the CPU device.
 398  */
 399 int register_cpu(struct cpu *cpu, int num)
 400 {
 401         int error;
 402
 403         cpu->node_id = cpu_to_node(num);
 404         memset(&cpu->dev, 0x00, sizeof(struct device));
 405         cpu->dev.id = num;
 406         cpu->dev.bus = &cpu_subsys;
 407         cpu->dev.release = cpu_device_release;
 408         cpu->dev.offline_disabled = !cpu->hotpluggable;
 409         cpu->dev.offline = !cpu_online(num);
 410         cpu->dev.of_node = of_get_cpu_node(num, NULL);
 411         cpu->dev.groups = common_cpu_attr_groups;
 412         if (cpu->hotpluggable)
 413                 cpu->dev.groups = hotplugable_cpu_attr_groups;
 414         error = device_register(&cpu->dev);
 415         if (error) {
 416                 put_device(&cpu->dev);
 417                 return error;
 418         }
 419
 420         per_cpu(cpu_sys_devices, num) = &cpu->dev;
 421         register_cpu_under_node(num, cpu_to_node(num));
 422         dev_pm_qos_expose_latency_limit(&cpu->dev,
 423                                         PM_QOS_RESUME_LATENCY_NO_CONSTRAINT);
 424         set_cpu_enabled(num, true);
 425
 426         return 0;
 427 }
 428
 429 struct device *get_cpu_device(unsigned int cpu)
 430 {
 431         if (cpu < nr_cpu_ids && cpu_possible(cpu))
 432                 return per_cpu(cpu_sys_devices, cpu);
 433         else
 434                 return NULL;
 435 }
 436 EXPORT_SYMBOL_GPL(get_cpu_device);
 437
 438 static void device_create_release(struct device *dev)
 439 {
 440         kfree(dev);
 441 }
 442
 443 __printf(4, 0)
 444 static struct device *
 445 __cpu_device_create(struct device *parent, void *drvdata,
 446                     const struct attribute_group **groups,
 447                     const char *fmt, va_list args)
 448 {
 449         struct device *dev = NULL;
 450         int retval = -ENOMEM;
 451
 452         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 453         if (!dev)
 454                 goto error;
 455
 456         device_initialize(dev);
 457         dev->parent = parent;
 458         dev->groups = groups;
 459         dev->release = device_create_release;
 460         device_set_pm_not_required(dev);
 461         dev_set_drvdata(dev, drvdata);
 462
 463         retval = kobject_set_name_vargs(&dev->kobj, fmt, args);
 464         if (retval)
 465                 goto error;
 466
 467         retval = device_add(dev);
 468         if (retval)
 469                 goto error;
 470
 471         return dev;
 472
 473 error:
 474         put_device(dev);
 475         return ERR_PTR(retval);
 476 }
 477
 478 struct device *cpu_device_create(struct device *parent, void *drvdata,
 479                                  const struct attribute_group **groups,
 480                                  const char *fmt, ...)
 481 {
 482         va_list vargs;
 483         struct device *dev;
 484
 485         va_start(vargs, fmt);
 486         dev = __cpu_device_create(parent, drvdata, groups, fmt, vargs);
 487         va_end(vargs);
 488         return dev;
 489 }
 490 EXPORT_SYMBOL_GPL(cpu_device_create);
 491
 492 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 493 static DEVICE_ATTR(modalias, 0444, print_cpu_modalias, NULL);
 494 #endif
 495
 496 static struct attribute *cpu_root_attrs[] = {
 497 #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE
 498         &dev_attr_probe.attr,
 499         &dev_attr_release.attr,
 500 #endif
 501         &cpu_attrs[0].attr.attr,
 502         &cpu_attrs[1].attr.attr,
 503         &cpu_attrs[2].attr.attr,
 504         &dev_attr_kernel_max.attr,
 505         &dev_attr_offline.attr,
 506         &dev_attr_enabled.attr,
 507         &dev_attr_isolated.attr,
 508 #ifdef CONFIG_NO_HZ_FULL
 509         &dev_attr_nohz_full.attr,
 510 #endif
 511 #ifdef CONFIG_CRASH_HOTPLUG
 512         &dev_attr_crash_hotplug.attr,
 513 #endif
 514 #ifdef CONFIG_GENERIC_CPU_AUTOPROBE
 515         &dev_attr_modalias.attr,
 516 #endif
 517         NULL
 518 };
 519
 520 static const struct attribute_group cpu_root_attr_group = {
 521         .attrs = cpu_root_attrs,
 522 };
 523
 524 static const struct attribute_group *cpu_root_attr_groups[] = {
 525         &cpu_root_attr_group,
 526         NULL,
 527 };
 528
 529 bool cpu_is_hotpluggable(unsigned int cpu)
 530 {
 531         struct device *dev = get_cpu_device(cpu);
 532         return dev && container_of(dev, struct cpu, dev)->hotpluggable
 533                 && tick_nohz_cpu_hotpluggable(cpu);
 534 }
 535 EXPORT_SYMBOL_GPL(cpu_is_hotpluggable);
 536
 537 #ifdef CONFIG_GENERIC_CPU_DEVICES
 538 DEFINE_PER_CPU(struct cpu, cpu_devices);
 539
 540 bool __weak arch_cpu_is_hotpluggable(int cpu)
 541 {
 542         return false;
 543 }
 544
 545 int __weak arch_register_cpu(int cpu)
 546 {
 547         struct cpu *c = &per_cpu(cpu_devices, cpu);
 548
 549         c->hotpluggable = arch_cpu_is_hotpluggable(cpu);
 550
 551         return register_cpu(c, cpu);
 552 }
 553
 554 #ifdef CONFIG_HOTPLUG_CPU
 555 void __weak arch_unregister_cpu(int num)
 556 {
 557         unregister_cpu(&per_cpu(cpu_devices, num));
 558 }
 559 #endif /* CONFIG_HOTPLUG_CPU */
 560 #endif /* CONFIG_GENERIC_CPU_DEVICES */
 561
 562 static void __init cpu_dev_register_generic(void)
 563 {
 564         int i, ret;
 565
 566         if (!IS_ENABLED(CONFIG_GENERIC_CPU_DEVICES))
 567                 return;
 568
 569         for_each_present_cpu(i) {
 570                 ret = arch_register_cpu(i);
 571                 if (ret && ret != -EPROBE_DEFER)
 572                         pr_warn("register_cpu %d failed (%d)\n", i, ret);
 573         }
 574 }
 575
 576 #ifdef CONFIG_GENERIC_CPU_VULNERABILITIES
 577 static ssize_t cpu_show_not_affected(struct device *dev,
 578                               struct device_attribute *attr, char *buf)
 579 {
 580         return sysfs_emit(buf, "Not affected\n");
 581 }
 582
 583 #define CPU_SHOW_VULN_FALLBACK(func)                                    \
 584         ssize_t cpu_show_##func(struct device *,                        \
 585                                   struct device_attribute *, char *)    \
 586                  __attribute__((weak, alias("cpu_show_not_affected")))
 587
 588 CPU_SHOW_VULN_FALLBACK(meltdown);
 589 CPU_SHOW_VULN_FALLBACK(spectre_v1);
 590 CPU_SHOW_VULN_FALLBACK(spectre_v2);
 591 CPU_SHOW_VULN_FALLBACK(spec_store_bypass);
 592 CPU_SHOW_VULN_FALLBACK(l1tf);
 593 CPU_SHOW_VULN_FALLBACK(mds);
 594 CPU_SHOW_VULN_FALLBACK(tsx_async_abort);
 595 CPU_SHOW_VULN_FALLBACK(itlb_multihit);
 596 CPU_SHOW_VULN_FALLBACK(srbds);
 597 CPU_SHOW_VULN_FALLBACK(mmio_stale_data);
 598 CPU_SHOW_VULN_FALLBACK(retbleed);
 599 CPU_SHOW_VULN_FALLBACK(spec_rstack_overflow);
 600 CPU_SHOW_VULN_FALLBACK(gds);
 601 CPU_SHOW_VULN_FALLBACK(reg_file_data_sampling);
 602
 603 static DEVICE_ATTR(meltdown, 0444, cpu_show_meltdown, NULL);
 604 static DEVICE_ATTR(spectre_v1, 0444, cpu_show_spectre_v1, NULL);
 605 static DEVICE_ATTR(spectre_v2, 0444, cpu_show_spectre_v2, NULL);
 606 static DEVICE_ATTR(spec_store_bypass, 0444, cpu_show_spec_store_bypass, NULL);
 607 static DEVICE_ATTR(l1tf, 0444, cpu_show_l1tf, NULL);
 608 static DEVICE_ATTR(mds, 0444, cpu_show_mds, NULL);
 609 static DEVICE_ATTR(tsx_async_abort, 0444, cpu_show_tsx_async_abort, NULL);
 610 static DEVICE_ATTR(itlb_multihit, 0444, cpu_show_itlb_multihit, NULL);
 611 static DEVICE_ATTR(srbds, 0444, cpu_show_srbds, NULL);
 612 static DEVICE_ATTR(mmio_stale_data, 0444, cpu_show_mmio_stale_data, NULL);
 613 static DEVICE_ATTR(retbleed, 0444, cpu_show_retbleed, NULL);
 614 static DEVICE_ATTR(spec_rstack_overflow, 0444, cpu_show_spec_rstack_overflow, NULL);
 615 static DEVICE_ATTR(gather_data_sampling, 0444, cpu_show_gds, NULL);
 616 static DEVICE_ATTR(reg_file_data_sampling, 0444, cpu_show_reg_file_data_sampling, NULL);
 617
 618 static struct attribute *cpu_root_vulnerabilities_attrs[] = {
 619         &dev_attr_meltdown.attr,
 620         &dev_attr_spectre_v1.attr,
 621         &dev_attr_spectre_v2.attr,
 622         &dev_attr_spec_store_bypass.attr,
 623         &dev_attr_l1tf.attr,
 624         &dev_attr_mds.attr,
 625         &dev_attr_tsx_async_abort.attr,
 626         &dev_attr_itlb_multihit.attr,
 627         &dev_attr_srbds.attr,
 628         &dev_attr_mmio_stale_data.attr,
 629         &dev_attr_retbleed.attr,
 630         &dev_attr_spec_rstack_overflow.attr,
 631         &dev_attr_gather_data_sampling.attr,
 632         &dev_attr_reg_file_data_sampling.attr,
 633         NULL
 634 };
 635
 636 static const struct attribute_group cpu_root_vulnerabilities_group = {
 637         .name  = "vulnerabilities",
 638         .attrs = cpu_root_vulnerabilities_attrs,
 639 };
 640
 641 static void __init cpu_register_vulnerabilities(void)
 642 {
 643         struct device *dev = bus_get_dev_root(&cpu_subsys);
 644
 645         if (dev) {
 646                 if (sysfs_create_group(&dev->kobj, &cpu_root_vulnerabilities_group))
 647                         pr_err("Unable to register CPU vulnerabilities\n");
 648                 put_device(dev);
 649         }
 650 }
 651
 652 #else
 653 static inline void cpu_register_vulnerabilities(void) { }
 654 #endif
 655
 656 void __init cpu_dev_init(void)
 657 {
 658         if (subsys_system_register(&cpu_subsys, cpu_root_attr_groups))
 659                 panic("Failed to register CPU subsystem");
 660
 661         cpu_dev_register_generic();
 662         cpu_register_vulnerabilities();
 663 }