drivers/base/cacheinfo.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cacheinfo support - processor cache information via sysfs
   4  *
   5  * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
   6  * Author: Sudeep Holla <sudeep.holla@arm.com>
   7  */
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/acpi.h>
  11 #include <linux/bitops.h>
  12 #include <linux/cacheinfo.h>
  13 #include <linux/compiler.h>
  14 #include <linux/cpu.h>
  15 #include <linux/device.h>
  16 #include <linux/init.h>
  17 #include <linux/of.h>
  18 #include <linux/sched.h>
  19 #include <linux/slab.h>
  20 #include <linux/smp.h>
  21 #include <linux/sysfs.h>
  22
  23 /* pointer to per cpu cacheinfo */
  24 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
  25 #define ci_cacheinfo(cpu)       (&per_cpu(ci_cpu_cacheinfo, cpu))
  26 #define cache_leaves(cpu)       (ci_cacheinfo(cpu)->num_leaves)
  27 #define per_cpu_cacheinfo(cpu)  (ci_cacheinfo(cpu)->info_list)
  28
  29 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
  30 {
  31         return ci_cacheinfo(cpu);
  32 }
  33
  34 #ifdef CONFIG_OF
  35 static int cache_setup_of_node(unsigned int cpu)
  36 {
  37         struct device_node *np;
  38         struct cacheinfo *this_leaf;
  39         struct device *cpu_dev = get_cpu_device(cpu);
  40         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
  41         unsigned int index = 0;
  42
  43         /* skip if of_node is already populated */
  44         if (this_cpu_ci->info_list->of_node)
  45                 return 0;
  46
  47         if (!cpu_dev) {
  48                 pr_err("No cpu device for CPU %d\n", cpu);
  49                 return -ENODEV;
  50         }
  51         np = cpu_dev->of_node;
  52         if (!np) {
  53                 pr_err("Failed to find cpu%d device node\n", cpu);
  54                 return -ENOENT;
  55         }
  56
  57         while (index < cache_leaves(cpu)) {
  58                 this_leaf = this_cpu_ci->info_list + index;
  59                 if (this_leaf->level != 1)
  60                         np = of_find_next_cache_node(np);
  61                 else
  62                         np = of_node_get(np);/* cpu node itself */
  63                 if (!np)
  64                         break;
  65                 this_leaf->of_node = np;
  66                 index++;
  67         }
  68
  69         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
  70                 return -ENOENT;
  71
  72         return 0;
  73 }
  74
  75 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  76                                            struct cacheinfo *sib_leaf)
  77 {
  78         return sib_leaf->of_node == this_leaf->of_node;
  79 }
  80
  81 /* OF properties to query for a given cache type */
  82 struct cache_type_info {
  83         const char *size_prop;
  84         const char *line_size_props[2];
  85         const char *nr_sets_prop;
  86 };
  87
  88 static const struct cache_type_info cache_type_info[] = {
  89         {
  90                 .size_prop       = "cache-size",
  91                 .line_size_props = { "cache-line-size",
  92                                      "cache-block-size", },
  93                 .nr_sets_prop    = "cache-sets",
  94         }, {
  95                 .size_prop       = "i-cache-size",
  96                 .line_size_props = { "i-cache-line-size",
  97                                      "i-cache-block-size", },
  98                 .nr_sets_prop    = "i-cache-sets",
  99         }, {
 100                 .size_prop       = "d-cache-size",
 101                 .line_size_props = { "d-cache-line-size",
 102                                      "d-cache-block-size", },
 103                 .nr_sets_prop    = "d-cache-sets",
 104         },
 105 };
 106
 107 static inline int get_cacheinfo_idx(enum cache_type type)
 108 {
 109         if (type == CACHE_TYPE_UNIFIED)
 110                 return 0;
 111         return type;
 112 }
 113
 114 static void cache_size(struct cacheinfo *this_leaf)
 115 {
 116         const char *propname;
 117         const __be32 *cache_size;
 118         int ct_idx;
 119
 120         ct_idx = get_cacheinfo_idx(this_leaf->type);
 121         propname = cache_type_info[ct_idx].size_prop;
 122
 123         cache_size = of_get_property(this_leaf->of_node, propname, NULL);
 124         if (cache_size)
 125                 this_leaf->size = of_read_number(cache_size, 1);
 126 }
 127
 128 /* not cache_line_size() because that's a macro in include/linux/cache.h */
 129 static void cache_get_line_size(struct cacheinfo *this_leaf)
 130 {
 131         const __be32 *line_size;
 132         int i, lim, ct_idx;
 133
 134         ct_idx = get_cacheinfo_idx(this_leaf->type);
 135         lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
 136
 137         for (i = 0; i < lim; i++) {
 138                 const char *propname;
 139
 140                 propname = cache_type_info[ct_idx].line_size_props[i];
 141                 line_size = of_get_property(this_leaf->of_node, propname, NULL);
 142                 if (line_size)
 143                         break;
 144         }
 145
 146         if (line_size)
 147                 this_leaf->coherency_line_size = of_read_number(line_size, 1);
 148 }
 149
 150 static void cache_nr_sets(struct cacheinfo *this_leaf)
 151 {
 152         const char *propname;
 153         const __be32 *nr_sets;
 154         int ct_idx;
 155
 156         ct_idx = get_cacheinfo_idx(this_leaf->type);
 157         propname = cache_type_info[ct_idx].nr_sets_prop;
 158
 159         nr_sets = of_get_property(this_leaf->of_node, propname, NULL);
 160         if (nr_sets)
 161                 this_leaf->number_of_sets = of_read_number(nr_sets, 1);
 162 }
 163
 164 static void cache_associativity(struct cacheinfo *this_leaf)
 165 {
 166         unsigned int line_size = this_leaf->coherency_line_size;
 167         unsigned int nr_sets = this_leaf->number_of_sets;
 168         unsigned int size = this_leaf->size;
 169
 170         /*
 171          * If the cache is fully associative, there is no need to
 172          * check the other properties.
 173          */
 174         if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
 175                 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
 176 }
 177
 178 static bool cache_node_is_unified(struct cacheinfo *this_leaf)
 179 {
 180         return of_property_read_bool(this_leaf->of_node, "cache-unified");
 181 }
 182
 183 static void cache_of_override_properties(unsigned int cpu)
 184 {
 185         int index;
 186         struct cacheinfo *this_leaf;
 187         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 188
 189         for (index = 0; index < cache_leaves(cpu); index++) {
 190                 this_leaf = this_cpu_ci->info_list + index;
 191                 /*
 192                  * init_cache_level must setup the cache level correctly
 193                  * overriding the architecturally specified levels, so
 194                  * if type is NONE at this stage, it should be unified
 195                  */
 196                 if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 197                     cache_node_is_unified(this_leaf))
 198                         this_leaf->type = CACHE_TYPE_UNIFIED;
 199                 cache_size(this_leaf);
 200                 cache_get_line_size(this_leaf);
 201                 cache_nr_sets(this_leaf);
 202                 cache_associativity(this_leaf);
 203         }
 204 }
 205 #else
 206 static void cache_of_override_properties(unsigned int cpu) { }
 207 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 208 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 209                                            struct cacheinfo *sib_leaf)
 210 {
 211         /*
 212          * For non-DT systems, assume unique level 1 cache, system-wide
 213          * shared caches for all other levels. This will be used only if
 214          * arch specific code has not populated shared_cpu_map
 215          */
 216         return !(this_leaf->level == 1);
 217 }
 218 #endif
 219
 220 static int cache_shared_cpu_map_setup(unsigned int cpu)
 221 {
 222         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 223         struct cacheinfo *this_leaf, *sib_leaf;
 224         unsigned int index;
 225         int ret = 0;
 226
 227         if (this_cpu_ci->cpu_map_populated)
 228                 return 0;
 229
 230         if (of_have_populated_dt())
 231                 ret = cache_setup_of_node(cpu);
 232         else if (!acpi_disabled)
 233                 /* No cache property/hierarchy support yet in ACPI */
 234                 ret = -ENOTSUPP;
 235         if (ret)
 236                 return ret;
 237
 238         for (index = 0; index < cache_leaves(cpu); index++) {
 239                 unsigned int i;
 240
 241                 this_leaf = this_cpu_ci->info_list + index;
 242                 /* skip if shared_cpu_map is already populated */
 243                 if (!cpumask_empty(&this_leaf->shared_cpu_map))
 244                         continue;
 245
 246                 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
 247                 for_each_online_cpu(i) {
 248                         struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
 249
 250                         if (i == cpu || !sib_cpu_ci->info_list)
 251                                 continue;/* skip if itself or no cacheinfo */
 252                         sib_leaf = sib_cpu_ci->info_list + index;
 253                         if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 254                                 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
 255                                 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
 256                         }
 257                 }
 258         }
 259
 260         return 0;
 261 }
 262
 263 static void cache_shared_cpu_map_remove(unsigned int cpu)
 264 {
 265         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 266         struct cacheinfo *this_leaf, *sib_leaf;
 267         unsigned int sibling, index;
 268
 269         for (index = 0; index < cache_leaves(cpu); index++) {
 270                 this_leaf = this_cpu_ci->info_list + index;
 271                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 272                         struct cpu_cacheinfo *sib_cpu_ci;
 273
 274                         if (sibling == cpu) /* skip itself */
 275                                 continue;
 276
 277                         sib_cpu_ci = get_cpu_cacheinfo(sibling);
 278                         if (!sib_cpu_ci->info_list)
 279                                 continue;
 280
 281                         sib_leaf = sib_cpu_ci->info_list + index;
 282                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 283                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 284                 }
 285                 of_node_put(this_leaf->of_node);
 286         }
 287 }
 288
 289 static void cache_override_properties(unsigned int cpu)
 290 {
 291         if (of_have_populated_dt())
 292                 return cache_of_override_properties(cpu);
 293 }
 294
 295 static void free_cache_attributes(unsigned int cpu)
 296 {
 297         if (!per_cpu_cacheinfo(cpu))
 298                 return;
 299
 300         cache_shared_cpu_map_remove(cpu);
 301
 302         kfree(per_cpu_cacheinfo(cpu));
 303         per_cpu_cacheinfo(cpu) = NULL;
 304 }
 305
 306 int __weak init_cache_level(unsigned int cpu)
 307 {
 308         return -ENOENT;
 309 }
 310
 311 int __weak populate_cache_leaves(unsigned int cpu)
 312 {
 313         return -ENOENT;
 314 }
 315
 316 static int detect_cache_attributes(unsigned int cpu)
 317 {
 318         int ret;
 319
 320         if (init_cache_level(cpu) || !cache_leaves(cpu))
 321                 return -ENOENT;
 322
 323         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 324                                          sizeof(struct cacheinfo), GFP_KERNEL);
 325         if (per_cpu_cacheinfo(cpu) == NULL)
 326                 return -ENOMEM;
 327
 328         ret = populate_cache_leaves(cpu);
 329         if (ret)
 330                 goto free_ci;
 331         /*
 332          * For systems using DT for cache hierarchy, of_node and shared_cpu_map
 333          * will be set up here only if they are not populated already
 334          */
 335         ret = cache_shared_cpu_map_setup(cpu);
 336         if (ret) {
 337                 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
 338                 goto free_ci;
 339         }
 340
 341         cache_override_properties(cpu);
 342         return 0;
 343
 344 free_ci:
 345         free_cache_attributes(cpu);
 346         return ret;
 347 }
 348
 349 /* pointer to cpuX/cache device */
 350 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 351 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 352
 353 static cpumask_t cache_dev_map;
 354
 355 /* pointer to array of devices for cpuX/cache/indexY */
 356 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 357 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 358 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 359
 360 #define show_one(file_name, object)                             \
 361 static ssize_t file_name##_show(struct device *dev,             \
 362                 struct device_attribute *attr, char *buf)       \
 363 {                                                               \
 364         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 365         return sprintf(buf, "%u\n", this_leaf->object);         \
 366 }
 367
 368 show_one(id, id);
 369 show_one(level, level);
 370 show_one(coherency_line_size, coherency_line_size);
 371 show_one(number_of_sets, number_of_sets);
 372 show_one(physical_line_partition, physical_line_partition);
 373 show_one(ways_of_associativity, ways_of_associativity);
 374
 375 static ssize_t size_show(struct device *dev,
 376                          struct device_attribute *attr, char *buf)
 377 {
 378         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 379
 380         return sprintf(buf, "%uK\n", this_leaf->size >> 10);
 381 }
 382
 383 static ssize_t shared_cpumap_show_func(struct device *dev, bool list, char *buf)
 384 {
 385         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 386         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 387
 388         return cpumap_print_to_pagebuf(list, buf, mask);
 389 }
 390
 391 static ssize_t shared_cpu_map_show(struct device *dev,
 392                                    struct device_attribute *attr, char *buf)
 393 {
 394         return shared_cpumap_show_func(dev, false, buf);
 395 }
 396
 397 static ssize_t shared_cpu_list_show(struct device *dev,
 398                                     struct device_attribute *attr, char *buf)
 399 {
 400         return shared_cpumap_show_func(dev, true, buf);
 401 }
 402
 403 static ssize_t type_show(struct device *dev,
 404                          struct device_attribute *attr, char *buf)
 405 {
 406         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 407
 408         switch (this_leaf->type) {
 409         case CACHE_TYPE_DATA:
 410                 return sprintf(buf, "Data\n");
 411         case CACHE_TYPE_INST:
 412                 return sprintf(buf, "Instruction\n");
 413         case CACHE_TYPE_UNIFIED:
 414                 return sprintf(buf, "Unified\n");
 415         default:
 416                 return -EINVAL;
 417         }
 418 }
 419
 420 static ssize_t allocation_policy_show(struct device *dev,
 421                                       struct device_attribute *attr, char *buf)
 422 {
 423         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 424         unsigned int ci_attr = this_leaf->attributes;
 425         int n = 0;
 426
 427         if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
 428                 n = sprintf(buf, "ReadWriteAllocate\n");
 429         else if (ci_attr & CACHE_READ_ALLOCATE)
 430                 n = sprintf(buf, "ReadAllocate\n");
 431         else if (ci_attr & CACHE_WRITE_ALLOCATE)
 432                 n = sprintf(buf, "WriteAllocate\n");
 433         return n;
 434 }
 435
 436 static ssize_t write_policy_show(struct device *dev,
 437                                  struct device_attribute *attr, char *buf)
 438 {
 439         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 440         unsigned int ci_attr = this_leaf->attributes;
 441         int n = 0;
 442
 443         if (ci_attr & CACHE_WRITE_THROUGH)
 444                 n = sprintf(buf, "WriteThrough\n");
 445         else if (ci_attr & CACHE_WRITE_BACK)
 446                 n = sprintf(buf, "WriteBack\n");
 447         return n;
 448 }
 449
 450 static DEVICE_ATTR_RO(id);
 451 static DEVICE_ATTR_RO(level);
 452 static DEVICE_ATTR_RO(type);
 453 static DEVICE_ATTR_RO(coherency_line_size);
 454 static DEVICE_ATTR_RO(ways_of_associativity);
 455 static DEVICE_ATTR_RO(number_of_sets);
 456 static DEVICE_ATTR_RO(size);
 457 static DEVICE_ATTR_RO(allocation_policy);
 458 static DEVICE_ATTR_RO(write_policy);
 459 static DEVICE_ATTR_RO(shared_cpu_map);
 460 static DEVICE_ATTR_RO(shared_cpu_list);
 461 static DEVICE_ATTR_RO(physical_line_partition);
 462
 463 static struct attribute *cache_default_attrs[] = {
 464         &dev_attr_id.attr,
 465         &dev_attr_type.attr,
 466         &dev_attr_level.attr,
 467         &dev_attr_shared_cpu_map.attr,
 468         &dev_attr_shared_cpu_list.attr,
 469         &dev_attr_coherency_line_size.attr,
 470         &dev_attr_ways_of_associativity.attr,
 471         &dev_attr_number_of_sets.attr,
 472         &dev_attr_size.attr,
 473         &dev_attr_allocation_policy.attr,
 474         &dev_attr_write_policy.attr,
 475         &dev_attr_physical_line_partition.attr,
 476         NULL
 477 };
 478
 479 static umode_t
 480 cache_default_attrs_is_visible(struct kobject *kobj,
 481                                struct attribute *attr, int unused)
 482 {
 483         struct device *dev = kobj_to_dev(kobj);
 484         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 485         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 486         umode_t mode = attr->mode;
 487
 488         if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
 489                 return mode;
 490         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 491                 return mode;
 492         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 493                 return mode;
 494         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 495                 return mode;
 496         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 497                 return mode;
 498         if ((attr == &dev_attr_coherency_line_size.attr) &&
 499             this_leaf->coherency_line_size)
 500                 return mode;
 501         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 502             this_leaf->size) /* allow 0 = full associativity */
 503                 return mode;
 504         if ((attr == &dev_attr_number_of_sets.attr) &&
 505             this_leaf->number_of_sets)
 506                 return mode;
 507         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 508                 return mode;
 509         if ((attr == &dev_attr_write_policy.attr) &&
 510             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 511                 return mode;
 512         if ((attr == &dev_attr_allocation_policy.attr) &&
 513             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 514                 return mode;
 515         if ((attr == &dev_attr_physical_line_partition.attr) &&
 516             this_leaf->physical_line_partition)
 517                 return mode;
 518
 519         return 0;
 520 }
 521
 522 static const struct attribute_group cache_default_group = {
 523         .attrs = cache_default_attrs,
 524         .is_visible = cache_default_attrs_is_visible,
 525 };
 526
 527 static const struct attribute_group *cache_default_groups[] = {
 528         &cache_default_group,
 529         NULL,
 530 };
 531
 532 static const struct attribute_group *cache_private_groups[] = {
 533         &cache_default_group,
 534         NULL, /* Place holder for private group */
 535         NULL,
 536 };
 537
 538 const struct attribute_group *
 539 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 540 {
 541         return NULL;
 542 }
 543
 544 static const struct attribute_group **
 545 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 546 {
 547         const struct attribute_group *priv_group =
 548                         cache_get_priv_group(this_leaf);
 549
 550         if (!priv_group)
 551                 return cache_default_groups;
 552
 553         if (!cache_private_groups[1])
 554                 cache_private_groups[1] = priv_group;
 555
 556         return cache_private_groups;
 557 }
 558
 559 /* Add/Remove cache interface for CPU device */
 560 static void cpu_cache_sysfs_exit(unsigned int cpu)
 561 {
 562         int i;
 563         struct device *ci_dev;
 564
 565         if (per_cpu_index_dev(cpu)) {
 566                 for (i = 0; i < cache_leaves(cpu); i++) {
 567                         ci_dev = per_cache_index_dev(cpu, i);
 568                         if (!ci_dev)
 569                                 continue;
 570                         device_unregister(ci_dev);
 571                 }
 572                 kfree(per_cpu_index_dev(cpu));
 573                 per_cpu_index_dev(cpu) = NULL;
 574         }
 575         device_unregister(per_cpu_cache_dev(cpu));
 576         per_cpu_cache_dev(cpu) = NULL;
 577 }
 578
 579 static int cpu_cache_sysfs_init(unsigned int cpu)
 580 {
 581         struct device *dev = get_cpu_device(cpu);
 582
 583         if (per_cpu_cacheinfo(cpu) == NULL)
 584                 return -ENOENT;
 585
 586         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 587         if (IS_ERR(per_cpu_cache_dev(cpu)))
 588                 return PTR_ERR(per_cpu_cache_dev(cpu));
 589
 590         /* Allocate all required memory */
 591         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 592                                          sizeof(struct device *), GFP_KERNEL);
 593         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 594                 goto err_out;
 595
 596         return 0;
 597
 598 err_out:
 599         cpu_cache_sysfs_exit(cpu);
 600         return -ENOMEM;
 601 }
 602
 603 static int cache_add_dev(unsigned int cpu)
 604 {
 605         unsigned int i;
 606         int rc;
 607         struct device *ci_dev, *parent;
 608         struct cacheinfo *this_leaf;
 609         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 610         const struct attribute_group **cache_groups;
 611
 612         rc = cpu_cache_sysfs_init(cpu);
 613         if (unlikely(rc < 0))
 614                 return rc;
 615
 616         parent = per_cpu_cache_dev(cpu);
 617         for (i = 0; i < cache_leaves(cpu); i++) {
 618                 this_leaf = this_cpu_ci->info_list + i;
 619                 if (this_leaf->disable_sysfs)
 620                         continue;
 621                 cache_groups = cache_get_attribute_groups(this_leaf);
 622                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 623                                            "index%1u", i);
 624                 if (IS_ERR(ci_dev)) {
 625                         rc = PTR_ERR(ci_dev);
 626                         goto err;
 627                 }
 628                 per_cache_index_dev(cpu, i) = ci_dev;
 629         }
 630         cpumask_set_cpu(cpu, &cache_dev_map);
 631
 632         return 0;
 633 err:
 634         cpu_cache_sysfs_exit(cpu);
 635         return rc;
 636 }
 637
 638 static int cacheinfo_cpu_online(unsigned int cpu)
 639 {
 640         int rc = detect_cache_attributes(cpu);
 641
 642         if (rc)
 643                 return rc;
 644         rc = cache_add_dev(cpu);
 645         if (rc)
 646                 free_cache_attributes(cpu);
 647         return rc;
 648 }
 649
 650 static int cacheinfo_cpu_pre_down(unsigned int cpu)
 651 {
 652         if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
 653                 cpu_cache_sysfs_exit(cpu);
 654
 655         free_cache_attributes(cpu);
 656         return 0;
 657 }
 658
 659 static int __init cacheinfo_sysfs_init(void)
 660 {
 661         return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "base/cacheinfo:online",
 662                                  cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 663 }
 664 device_initcall(cacheinfo_sysfs_init);