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