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 inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  36                                            struct cacheinfo *sib_leaf)
  37 {
  38         return sib_leaf->fw_token == this_leaf->fw_token;
  39 }
  40
  41 /* OF properties to query for a given cache type */
  42 struct cache_type_info {
  43         const char *size_prop;
  44         const char *line_size_props[2];
  45         const char *nr_sets_prop;
  46 };
  47
  48 static const struct cache_type_info cache_type_info[] = {
  49         {
  50                 .size_prop       = "cache-size",
  51                 .line_size_props = { "cache-line-size",
  52                                      "cache-block-size", },
  53                 .nr_sets_prop    = "cache-sets",
  54         }, {
  55                 .size_prop       = "i-cache-size",
  56                 .line_size_props = { "i-cache-line-size",
  57                                      "i-cache-block-size", },
  58                 .nr_sets_prop    = "i-cache-sets",
  59         }, {
  60                 .size_prop       = "d-cache-size",
  61                 .line_size_props = { "d-cache-line-size",
  62                                      "d-cache-block-size", },
  63                 .nr_sets_prop    = "d-cache-sets",
  64         },
  65 };
  66
  67 static inline int get_cacheinfo_idx(enum cache_type type)
  68 {
  69         if (type == CACHE_TYPE_UNIFIED)
  70                 return 0;
  71         return type;
  72 }
  73
  74 static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
  75 {
  76         const char *propname;
  77         int ct_idx;
  78
  79         ct_idx = get_cacheinfo_idx(this_leaf->type);
  80         propname = cache_type_info[ct_idx].size_prop;
  81
  82         of_property_read_u32(np, propname, &this_leaf->size);
  83 }
  84
  85 /* not cache_line_size() because that's a macro in include/linux/cache.h */
  86 static void cache_get_line_size(struct cacheinfo *this_leaf,
  87                                 struct device_node *np)
  88 {
  89         int i, lim, ct_idx;
  90
  91         ct_idx = get_cacheinfo_idx(this_leaf->type);
  92         lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
  93
  94         for (i = 0; i < lim; i++) {
  95                 int ret;
  96                 u32 line_size;
  97                 const char *propname;
  98
  99                 propname = cache_type_info[ct_idx].line_size_props[i];
 100                 ret = of_property_read_u32(np, propname, &line_size);
 101                 if (!ret) {
 102                         this_leaf->coherency_line_size = line_size;
 103                         break;
 104                 }
 105         }
 106 }
 107
 108 static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
 109 {
 110         const char *propname;
 111         int ct_idx;
 112
 113         ct_idx = get_cacheinfo_idx(this_leaf->type);
 114         propname = cache_type_info[ct_idx].nr_sets_prop;
 115
 116         of_property_read_u32(np, propname, &this_leaf->number_of_sets);
 117 }
 118
 119 static void cache_associativity(struct cacheinfo *this_leaf)
 120 {
 121         unsigned int line_size = this_leaf->coherency_line_size;
 122         unsigned int nr_sets = this_leaf->number_of_sets;
 123         unsigned int size = this_leaf->size;
 124
 125         /*
 126          * If the cache is fully associative, there is no need to
 127          * check the other properties.
 128          */
 129         if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
 130                 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
 131 }
 132
 133 static bool cache_node_is_unified(struct cacheinfo *this_leaf,
 134                                   struct device_node *np)
 135 {
 136         return of_property_read_bool(np, "cache-unified");
 137 }
 138
 139 static void cache_of_set_props(struct cacheinfo *this_leaf,
 140                                struct device_node *np)
 141 {
 142         /*
 143          * init_cache_level must setup the cache level correctly
 144          * overriding the architecturally specified levels, so
 145          * if type is NONE at this stage, it should be unified
 146          */
 147         if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 148             cache_node_is_unified(this_leaf, np))
 149                 this_leaf->type = CACHE_TYPE_UNIFIED;
 150         cache_size(this_leaf, np);
 151         cache_get_line_size(this_leaf, np);
 152         cache_nr_sets(this_leaf, np);
 153         cache_associativity(this_leaf);
 154 }
 155
 156 static int cache_setup_of_node(unsigned int cpu)
 157 {
 158         struct device_node *np;
 159         struct cacheinfo *this_leaf;
 160         struct device *cpu_dev = get_cpu_device(cpu);
 161         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 162         unsigned int index = 0;
 163
 164         /* skip if fw_token is already populated */
 165         if (this_cpu_ci->info_list->fw_token) {
 166                 return 0;
 167         }
 168
 169         if (!cpu_dev) {
 170                 pr_err("No cpu device for CPU %d\n", cpu);
 171                 return -ENODEV;
 172         }
 173         np = cpu_dev->of_node;
 174         if (!np) {
 175                 pr_err("Failed to find cpu%d device node\n", cpu);
 176                 return -ENOENT;
 177         }
 178
 179         while (index < cache_leaves(cpu)) {
 180                 this_leaf = this_cpu_ci->info_list + index;
 181                 if (this_leaf->level != 1)
 182                         np = of_find_next_cache_node(np);
 183                 else
 184                         np = of_node_get(np);/* cpu node itself */
 185                 if (!np)
 186                         break;
 187                 cache_of_set_props(this_leaf, np);
 188                 this_leaf->fw_token = np;
 189                 index++;
 190         }
 191
 192         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
 193                 return -ENOENT;
 194
 195         return 0;
 196 }
 197 #else
 198 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 199 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 200                                            struct cacheinfo *sib_leaf)
 201 {
 202         /*
 203          * For non-DT/ACPI systems, assume unique level 1 caches, system-wide
 204          * shared caches for all other levels. This will be used only if
 205          * arch specific code has not populated shared_cpu_map
 206          */
 207         return !(this_leaf->level == 1);
 208 }
 209 #endif
 210
 211 int __weak cache_setup_acpi(unsigned int cpu)
 212 {
 213         return -ENOTSUPP;
 214 }
 215
 216 unsigned int coherency_max_size;
 217
 218 static int cache_shared_cpu_map_setup(unsigned int cpu)
 219 {
 220         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 221         struct cacheinfo *this_leaf, *sib_leaf;
 222         unsigned int index;
 223         int ret = 0;
 224
 225         if (this_cpu_ci->cpu_map_populated)
 226                 return 0;
 227
 228         if (of_have_populated_dt())
 229                 ret = cache_setup_of_node(cpu);
 230         else if (!acpi_disabled)
 231                 ret = cache_setup_acpi(cpu);
 232
 233         if (ret)
 234                 return ret;
 235
 236         for (index = 0; index < cache_leaves(cpu); index++) {
 237                 unsigned int i;
 238
 239                 this_leaf = this_cpu_ci->info_list + index;
 240                 /* skip if shared_cpu_map is already populated */
 241                 if (!cpumask_empty(&this_leaf->shared_cpu_map))
 242                         continue;
 243
 244                 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
 245                 for_each_online_cpu(i) {
 246                         struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
 247
 248                         if (i == cpu || !sib_cpu_ci->info_list)
 249                                 continue;/* skip if itself or no cacheinfo */
 250                         sib_leaf = sib_cpu_ci->info_list + index;
 251                         if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 252                                 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
 253                                 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
 254                         }
 255                 }
 256                 /* record the maximum cache line size */
 257                 if (this_leaf->coherency_line_size > coherency_max_size)
 258                         coherency_max_size = this_leaf->coherency_line_size;
 259         }
 260
 261         return 0;
 262 }
 263
 264 static void cache_shared_cpu_map_remove(unsigned int cpu)
 265 {
 266         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 267         struct cacheinfo *this_leaf, *sib_leaf;
 268         unsigned int sibling, index;
 269
 270         for (index = 0; index < cache_leaves(cpu); index++) {
 271                 this_leaf = this_cpu_ci->info_list + index;
 272                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 273                         struct cpu_cacheinfo *sib_cpu_ci;
 274
 275                         if (sibling == cpu) /* skip itself */
 276                                 continue;
 277
 278                         sib_cpu_ci = get_cpu_cacheinfo(sibling);
 279                         if (!sib_cpu_ci->info_list)
 280                                 continue;
 281
 282                         sib_leaf = sib_cpu_ci->info_list + index;
 283                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 284                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 285                 }
 286                 if (of_have_populated_dt())
 287                         of_node_put(this_leaf->fw_token);
 288         }
 289 }
 290
 291 static void free_cache_attributes(unsigned int cpu)
 292 {
 293         if (!per_cpu_cacheinfo(cpu))
 294                 return;
 295
 296         cache_shared_cpu_map_remove(cpu);
 297
 298         kfree(per_cpu_cacheinfo(cpu));
 299         per_cpu_cacheinfo(cpu) = NULL;
 300 }
 301
 302 int __weak init_cache_level(unsigned int cpu)
 303 {
 304         return -ENOENT;
 305 }
 306
 307 int __weak populate_cache_leaves(unsigned int cpu)
 308 {
 309         return -ENOENT;
 310 }
 311
 312 static int detect_cache_attributes(unsigned int cpu)
 313 {
 314         int ret;
 315
 316         if (init_cache_level(cpu) || !cache_leaves(cpu))
 317                 return -ENOENT;
 318
 319         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 320                                          sizeof(struct cacheinfo), GFP_KERNEL);
 321         if (per_cpu_cacheinfo(cpu) == NULL)
 322                 return -ENOMEM;
 323
 324         /*
 325          * populate_cache_leaves() may completely setup the cache leaves and
 326          * shared_cpu_map or it may leave it partially setup.
 327          */
 328         ret = populate_cache_leaves(cpu);
 329         if (ret)
 330                 goto free_ci;
 331         /*
 332          * For systems using DT for cache hierarchy, fw_token
 333          * and shared_cpu_map will be set up here only if they are
 334          * not populated already
 335          */
 336         ret = cache_shared_cpu_map_setup(cpu);
 337         if (ret) {
 338                 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
 339                 goto free_ci;
 340         }
 341
 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                 if (this_leaf->type == CACHE_TYPE_NOCACHE)
 622                         break;
 623                 cache_groups = cache_get_attribute_groups(this_leaf);
 624                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 625                                            "index%1u", i);
 626                 if (IS_ERR(ci_dev)) {
 627                         rc = PTR_ERR(ci_dev);
 628                         goto err;
 629                 }
 630                 per_cache_index_dev(cpu, i) = ci_dev;
 631         }
 632         cpumask_set_cpu(cpu, &cache_dev_map);
 633
 634         return 0;
 635 err:
 636         cpu_cache_sysfs_exit(cpu);
 637         return rc;
 638 }
 639
 640 static int cacheinfo_cpu_online(unsigned int cpu)
 641 {
 642         int rc = detect_cache_attributes(cpu);
 643
 644         if (rc)
 645                 return rc;
 646         rc = cache_add_dev(cpu);
 647         if (rc)
 648                 free_cache_attributes(cpu);
 649         return rc;
 650 }
 651
 652 static int cacheinfo_cpu_pre_down(unsigned int cpu)
 653 {
 654         if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
 655                 cpu_cache_sysfs_exit(cpu);
 656
 657         free_cache_attributes(cpu);
 658         return 0;
 659 }
 660
 661 static int __init cacheinfo_sysfs_init(void)
 662 {
 663         return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
 664                                  "base/cacheinfo:online",
 665                                  cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 666 }
 667 device_initcall(cacheinfo_sysfs_init);