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         if (of_property_read_u32(np, propname, &this_leaf->size))
  83                 this_leaf->size = 0;
  84 }
  85
  86 /* not cache_line_size() because that's a macro in include/linux/cache.h */
  87 static void cache_get_line_size(struct cacheinfo *this_leaf,
  88                                 struct device_node *np)
  89 {
  90         int i, lim, ct_idx;
  91
  92         ct_idx = get_cacheinfo_idx(this_leaf->type);
  93         lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
  94
  95         for (i = 0; i < lim; i++) {
  96                 int ret;
  97                 u32 line_size;
  98                 const char *propname;
  99
 100                 propname = cache_type_info[ct_idx].line_size_props[i];
 101                 ret = of_property_read_u32(np, propname, &line_size);
 102                 if (!ret) {
 103                         this_leaf->coherency_line_size = line_size;
 104                         break;
 105                 }
 106         }
 107 }
 108
 109 static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
 110 {
 111         const char *propname;
 112         int ct_idx;
 113
 114         ct_idx = get_cacheinfo_idx(this_leaf->type);
 115         propname = cache_type_info[ct_idx].nr_sets_prop;
 116
 117         if (of_property_read_u32(np, propname, &this_leaf->number_of_sets))
 118                 this_leaf->number_of_sets = 0;
 119 }
 120
 121 static void cache_associativity(struct cacheinfo *this_leaf)
 122 {
 123         unsigned int line_size = this_leaf->coherency_line_size;
 124         unsigned int nr_sets = this_leaf->number_of_sets;
 125         unsigned int size = this_leaf->size;
 126
 127         /*
 128          * If the cache is fully associative, there is no need to
 129          * check the other properties.
 130          */
 131         if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
 132                 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
 133 }
 134
 135 static bool cache_node_is_unified(struct cacheinfo *this_leaf,
 136                                   struct device_node *np)
 137 {
 138         return of_property_read_bool(np, "cache-unified");
 139 }
 140
 141 static void cache_of_set_props(struct cacheinfo *this_leaf,
 142                                struct device_node *np)
 143 {
 144         /*
 145          * init_cache_level must setup the cache level correctly
 146          * overriding the architecturally specified levels, so
 147          * if type is NONE at this stage, it should be unified
 148          */
 149         if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 150             cache_node_is_unified(this_leaf, np))
 151                 this_leaf->type = CACHE_TYPE_UNIFIED;
 152         cache_size(this_leaf, np);
 153         cache_get_line_size(this_leaf, np);
 154         cache_nr_sets(this_leaf, np);
 155         cache_associativity(this_leaf);
 156 }
 157
 158 static int cache_setup_of_node(unsigned int cpu)
 159 {
 160         struct device_node *np;
 161         struct cacheinfo *this_leaf;
 162         struct device *cpu_dev = get_cpu_device(cpu);
 163         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 164         unsigned int index = 0;
 165
 166         /* skip if fw_token is already populated */
 167         if (this_cpu_ci->info_list->fw_token) {
 168                 return 0;
 169         }
 170
 171         if (!cpu_dev) {
 172                 pr_err("No cpu device for CPU %d\n", cpu);
 173                 return -ENODEV;
 174         }
 175         np = cpu_dev->of_node;
 176         if (!np) {
 177                 pr_err("Failed to find cpu%d device node\n", cpu);
 178                 return -ENOENT;
 179         }
 180
 181         while (index < cache_leaves(cpu)) {
 182                 this_leaf = this_cpu_ci->info_list + index;
 183                 if (this_leaf->level != 1)
 184                         np = of_find_next_cache_node(np);
 185                 else
 186                         np = of_node_get(np);/* cpu node itself */
 187                 if (!np)
 188                         break;
 189                 cache_of_set_props(this_leaf, np);
 190                 this_leaf->fw_token = np;
 191                 index++;
 192         }
 193
 194         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
 195                 return -ENOENT;
 196
 197         return 0;
 198 }
 199 #else
 200 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 201 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 202                                            struct cacheinfo *sib_leaf)
 203 {
 204         /*
 205          * For non-DT/ACPI systems, assume unique level 1 caches, system-wide
 206          * shared caches for all other levels. This will be used only if
 207          * arch specific code has not populated shared_cpu_map
 208          */
 209         return !(this_leaf->level == 1);
 210 }
 211 #endif
 212
 213 int __weak cache_setup_acpi(unsigned int cpu)
 214 {
 215         return -ENOTSUPP;
 216 }
 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         }
 257
 258         return 0;
 259 }
 260
 261 static void cache_shared_cpu_map_remove(unsigned int cpu)
 262 {
 263         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 264         struct cacheinfo *this_leaf, *sib_leaf;
 265         unsigned int sibling, index;
 266
 267         for (index = 0; index < cache_leaves(cpu); index++) {
 268                 this_leaf = this_cpu_ci->info_list + index;
 269                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 270                         struct cpu_cacheinfo *sib_cpu_ci;
 271
 272                         if (sibling == cpu) /* skip itself */
 273                                 continue;
 274
 275                         sib_cpu_ci = get_cpu_cacheinfo(sibling);
 276                         if (!sib_cpu_ci->info_list)
 277                                 continue;
 278
 279                         sib_leaf = sib_cpu_ci->info_list + index;
 280                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 281                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 282                 }
 283                 if (of_have_populated_dt())
 284                         of_node_put(this_leaf->fw_token);
 285         }
 286 }
 287
 288 static void free_cache_attributes(unsigned int cpu)
 289 {
 290         if (!per_cpu_cacheinfo(cpu))
 291                 return;
 292
 293         cache_shared_cpu_map_remove(cpu);
 294
 295         kfree(per_cpu_cacheinfo(cpu));
 296         per_cpu_cacheinfo(cpu) = NULL;
 297 }
 298
 299 int __weak init_cache_level(unsigned int cpu)
 300 {
 301         return -ENOENT;
 302 }
 303
 304 int __weak populate_cache_leaves(unsigned int cpu)
 305 {
 306         return -ENOENT;
 307 }
 308
 309 static int detect_cache_attributes(unsigned int cpu)
 310 {
 311         int ret;
 312
 313         if (init_cache_level(cpu) || !cache_leaves(cpu))
 314                 return -ENOENT;
 315
 316         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 317                                          sizeof(struct cacheinfo), GFP_KERNEL);
 318         if (per_cpu_cacheinfo(cpu) == NULL)
 319                 return -ENOMEM;
 320
 321         /*
 322          * populate_cache_leaves() may completely setup the cache leaves and
 323          * shared_cpu_map or it may leave it partially setup.
 324          */
 325         ret = populate_cache_leaves(cpu);
 326         if (ret)
 327                 goto free_ci;
 328         /*
 329          * For systems using DT for cache hierarchy, fw_token
 330          * and shared_cpu_map will be set up here only if they are
 331          * not populated already
 332          */
 333         ret = cache_shared_cpu_map_setup(cpu);
 334         if (ret) {
 335                 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
 336                 goto free_ci;
 337         }
 338
 339         return 0;
 340
 341 free_ci:
 342         free_cache_attributes(cpu);
 343         return ret;
 344 }
 345
 346 /* pointer to cpuX/cache device */
 347 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 348 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 349
 350 static cpumask_t cache_dev_map;
 351
 352 /* pointer to array of devices for cpuX/cache/indexY */
 353 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 354 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 355 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 356
 357 #define show_one(file_name, object)                             \
 358 static ssize_t file_name##_show(struct device *dev,             \
 359                 struct device_attribute *attr, char *buf)       \
 360 {                                                               \
 361         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 362         return sprintf(buf, "%u\n", this_leaf->object);         \
 363 }
 364
 365 show_one(id, id);
 366 show_one(level, level);
 367 show_one(coherency_line_size, coherency_line_size);
 368 show_one(number_of_sets, number_of_sets);
 369 show_one(physical_line_partition, physical_line_partition);
 370 show_one(ways_of_associativity, ways_of_associativity);
 371
 372 static ssize_t size_show(struct device *dev,
 373                          struct device_attribute *attr, char *buf)
 374 {
 375         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 376
 377         return sprintf(buf, "%uK\n", this_leaf->size >> 10);
 378 }
 379
 380 static ssize_t shared_cpumap_show_func(struct device *dev, bool list, char *buf)
 381 {
 382         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 383         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 384
 385         return cpumap_print_to_pagebuf(list, buf, mask);
 386 }
 387
 388 static ssize_t shared_cpu_map_show(struct device *dev,
 389                                    struct device_attribute *attr, char *buf)
 390 {
 391         return shared_cpumap_show_func(dev, false, buf);
 392 }
 393
 394 static ssize_t shared_cpu_list_show(struct device *dev,
 395                                     struct device_attribute *attr, char *buf)
 396 {
 397         return shared_cpumap_show_func(dev, true, buf);
 398 }
 399
 400 static ssize_t type_show(struct device *dev,
 401                          struct device_attribute *attr, char *buf)
 402 {
 403         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 404
 405         switch (this_leaf->type) {
 406         case CACHE_TYPE_DATA:
 407                 return sprintf(buf, "Data\n");
 408         case CACHE_TYPE_INST:
 409                 return sprintf(buf, "Instruction\n");
 410         case CACHE_TYPE_UNIFIED:
 411                 return sprintf(buf, "Unified\n");
 412         default:
 413                 return -EINVAL;
 414         }
 415 }
 416
 417 static ssize_t allocation_policy_show(struct device *dev,
 418                                       struct device_attribute *attr, char *buf)
 419 {
 420         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 421         unsigned int ci_attr = this_leaf->attributes;
 422         int n = 0;
 423
 424         if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
 425                 n = sprintf(buf, "ReadWriteAllocate\n");
 426         else if (ci_attr & CACHE_READ_ALLOCATE)
 427                 n = sprintf(buf, "ReadAllocate\n");
 428         else if (ci_attr & CACHE_WRITE_ALLOCATE)
 429                 n = sprintf(buf, "WriteAllocate\n");
 430         return n;
 431 }
 432
 433 static ssize_t write_policy_show(struct device *dev,
 434                                  struct device_attribute *attr, char *buf)
 435 {
 436         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 437         unsigned int ci_attr = this_leaf->attributes;
 438         int n = 0;
 439
 440         if (ci_attr & CACHE_WRITE_THROUGH)
 441                 n = sprintf(buf, "WriteThrough\n");
 442         else if (ci_attr & CACHE_WRITE_BACK)
 443                 n = sprintf(buf, "WriteBack\n");
 444         return n;
 445 }
 446
 447 static DEVICE_ATTR_RO(id);
 448 static DEVICE_ATTR_RO(level);
 449 static DEVICE_ATTR_RO(type);
 450 static DEVICE_ATTR_RO(coherency_line_size);
 451 static DEVICE_ATTR_RO(ways_of_associativity);
 452 static DEVICE_ATTR_RO(number_of_sets);
 453 static DEVICE_ATTR_RO(size);
 454 static DEVICE_ATTR_RO(allocation_policy);
 455 static DEVICE_ATTR_RO(write_policy);
 456 static DEVICE_ATTR_RO(shared_cpu_map);
 457 static DEVICE_ATTR_RO(shared_cpu_list);
 458 static DEVICE_ATTR_RO(physical_line_partition);
 459
 460 static struct attribute *cache_default_attrs[] = {
 461         &dev_attr_id.attr,
 462         &dev_attr_type.attr,
 463         &dev_attr_level.attr,
 464         &dev_attr_shared_cpu_map.attr,
 465         &dev_attr_shared_cpu_list.attr,
 466         &dev_attr_coherency_line_size.attr,
 467         &dev_attr_ways_of_associativity.attr,
 468         &dev_attr_number_of_sets.attr,
 469         &dev_attr_size.attr,
 470         &dev_attr_allocation_policy.attr,
 471         &dev_attr_write_policy.attr,
 472         &dev_attr_physical_line_partition.attr,
 473         NULL
 474 };
 475
 476 static umode_t
 477 cache_default_attrs_is_visible(struct kobject *kobj,
 478                                struct attribute *attr, int unused)
 479 {
 480         struct device *dev = kobj_to_dev(kobj);
 481         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 482         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 483         umode_t mode = attr->mode;
 484
 485         if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
 486                 return mode;
 487         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 488                 return mode;
 489         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 490                 return mode;
 491         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 492                 return mode;
 493         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 494                 return mode;
 495         if ((attr == &dev_attr_coherency_line_size.attr) &&
 496             this_leaf->coherency_line_size)
 497                 return mode;
 498         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 499             this_leaf->size) /* allow 0 = full associativity */
 500                 return mode;
 501         if ((attr == &dev_attr_number_of_sets.attr) &&
 502             this_leaf->number_of_sets)
 503                 return mode;
 504         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 505                 return mode;
 506         if ((attr == &dev_attr_write_policy.attr) &&
 507             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 508                 return mode;
 509         if ((attr == &dev_attr_allocation_policy.attr) &&
 510             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 511                 return mode;
 512         if ((attr == &dev_attr_physical_line_partition.attr) &&
 513             this_leaf->physical_line_partition)
 514                 return mode;
 515
 516         return 0;
 517 }
 518
 519 static const struct attribute_group cache_default_group = {
 520         .attrs = cache_default_attrs,
 521         .is_visible = cache_default_attrs_is_visible,
 522 };
 523
 524 static const struct attribute_group *cache_default_groups[] = {
 525         &cache_default_group,
 526         NULL,
 527 };
 528
 529 static const struct attribute_group *cache_private_groups[] = {
 530         &cache_default_group,
 531         NULL, /* Place holder for private group */
 532         NULL,
 533 };
 534
 535 const struct attribute_group *
 536 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 537 {
 538         return NULL;
 539 }
 540
 541 static const struct attribute_group **
 542 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 543 {
 544         const struct attribute_group *priv_group =
 545                         cache_get_priv_group(this_leaf);
 546
 547         if (!priv_group)
 548                 return cache_default_groups;
 549
 550         if (!cache_private_groups[1])
 551                 cache_private_groups[1] = priv_group;
 552
 553         return cache_private_groups;
 554 }
 555
 556 /* Add/Remove cache interface for CPU device */
 557 static void cpu_cache_sysfs_exit(unsigned int cpu)
 558 {
 559         int i;
 560         struct device *ci_dev;
 561
 562         if (per_cpu_index_dev(cpu)) {
 563                 for (i = 0; i < cache_leaves(cpu); i++) {
 564                         ci_dev = per_cache_index_dev(cpu, i);
 565                         if (!ci_dev)
 566                                 continue;
 567                         device_unregister(ci_dev);
 568                 }
 569                 kfree(per_cpu_index_dev(cpu));
 570                 per_cpu_index_dev(cpu) = NULL;
 571         }
 572         device_unregister(per_cpu_cache_dev(cpu));
 573         per_cpu_cache_dev(cpu) = NULL;
 574 }
 575
 576 static int cpu_cache_sysfs_init(unsigned int cpu)
 577 {
 578         struct device *dev = get_cpu_device(cpu);
 579
 580         if (per_cpu_cacheinfo(cpu) == NULL)
 581                 return -ENOENT;
 582
 583         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 584         if (IS_ERR(per_cpu_cache_dev(cpu)))
 585                 return PTR_ERR(per_cpu_cache_dev(cpu));
 586
 587         /* Allocate all required memory */
 588         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 589                                          sizeof(struct device *), GFP_KERNEL);
 590         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 591                 goto err_out;
 592
 593         return 0;
 594
 595 err_out:
 596         cpu_cache_sysfs_exit(cpu);
 597         return -ENOMEM;
 598 }
 599
 600 static int cache_add_dev(unsigned int cpu)
 601 {
 602         unsigned int i;
 603         int rc;
 604         struct device *ci_dev, *parent;
 605         struct cacheinfo *this_leaf;
 606         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 607         const struct attribute_group **cache_groups;
 608
 609         rc = cpu_cache_sysfs_init(cpu);
 610         if (unlikely(rc < 0))
 611                 return rc;
 612
 613         parent = per_cpu_cache_dev(cpu);
 614         for (i = 0; i < cache_leaves(cpu); i++) {
 615                 this_leaf = this_cpu_ci->info_list + i;
 616                 if (this_leaf->disable_sysfs)
 617                         continue;
 618                 cache_groups = cache_get_attribute_groups(this_leaf);
 619                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 620                                            "index%1u", i);
 621                 if (IS_ERR(ci_dev)) {
 622                         rc = PTR_ERR(ci_dev);
 623                         goto err;
 624                 }
 625                 per_cache_index_dev(cpu, i) = ci_dev;
 626         }
 627         cpumask_set_cpu(cpu, &cache_dev_map);
 628
 629         return 0;
 630 err:
 631         cpu_cache_sysfs_exit(cpu);
 632         return rc;
 633 }
 634
 635 static int cacheinfo_cpu_online(unsigned int cpu)
 636 {
 637         int rc = detect_cache_attributes(cpu);
 638
 639         if (rc)
 640                 return rc;
 641         rc = cache_add_dev(cpu);
 642         if (rc)
 643                 free_cache_attributes(cpu);
 644         return rc;
 645 }
 646
 647 static int cacheinfo_cpu_pre_down(unsigned int cpu)
 648 {
 649         if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
 650                 cpu_cache_sysfs_exit(cpu);
 651
 652         free_cache_attributes(cpu);
 653         return 0;
 654 }
 655
 656 static int __init cacheinfo_sysfs_init(void)
 657 {
 658         return cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "base/cacheinfo:online",
 659                                  cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 660 }
 661 device_initcall(cacheinfo_sysfs_init);