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_device.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 #define per_cpu_cacheinfo_idx(cpu, idx)         \
  29                                 (per_cpu_cacheinfo(cpu) + (idx))
  30
  31 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
  32 {
  33         return ci_cacheinfo(cpu);
  34 }
  35
  36 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  37                                            struct cacheinfo *sib_leaf)
  38 {
  39         /*
  40          * For non DT/ACPI systems, assume unique level 1 caches,
  41          * system-wide shared caches for all other levels. This will be used
  42          * only if arch specific code has not populated shared_cpu_map
  43          */
  44         if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))
  45                 return !(this_leaf->level == 1);
  46
  47         if ((sib_leaf->attributes & CACHE_ID) &&
  48             (this_leaf->attributes & CACHE_ID))
  49                 return sib_leaf->id == this_leaf->id;
  50
  51         return sib_leaf->fw_token == this_leaf->fw_token;
  52 }
  53
  54 bool last_level_cache_is_valid(unsigned int cpu)
  55 {
  56         struct cacheinfo *llc;
  57
  58         if (!cache_leaves(cpu))
  59                 return false;
  60
  61         llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
  62
  63         return (llc->attributes & CACHE_ID) || !!llc->fw_token;
  64
  65 }
  66
  67 bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
  68 {
  69         struct cacheinfo *llc_x, *llc_y;
  70
  71         if (!last_level_cache_is_valid(cpu_x) ||
  72             !last_level_cache_is_valid(cpu_y))
  73                 return false;
  74
  75         llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1);
  76         llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1);
  77
  78         return cache_leaves_are_shared(llc_x, llc_y);
  79 }
  80
  81 #ifdef CONFIG_OF
  82 /* OF properties to query for a given cache type */
  83 struct cache_type_info {
  84         const char *size_prop;
  85         const char *line_size_props[2];
  86         const char *nr_sets_prop;
  87 };
  88
  89 static const struct cache_type_info cache_type_info[] = {
  90         {
  91                 .size_prop       = "cache-size",
  92                 .line_size_props = { "cache-line-size",
  93                                      "cache-block-size", },
  94                 .nr_sets_prop    = "cache-sets",
  95         }, {
  96                 .size_prop       = "i-cache-size",
  97                 .line_size_props = { "i-cache-line-size",
  98                                      "i-cache-block-size", },
  99                 .nr_sets_prop    = "i-cache-sets",
 100         }, {
 101                 .size_prop       = "d-cache-size",
 102                 .line_size_props = { "d-cache-line-size",
 103                                      "d-cache-block-size", },
 104                 .nr_sets_prop    = "d-cache-sets",
 105         },
 106 };
 107
 108 static inline int get_cacheinfo_idx(enum cache_type type)
 109 {
 110         if (type == CACHE_TYPE_UNIFIED)
 111                 return 0;
 112         return type;
 113 }
 114
 115 static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
 116 {
 117         const char *propname;
 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         of_property_read_u32(np, propname, &this_leaf->size);
 124 }
 125
 126 /* not cache_line_size() because that's a macro in include/linux/cache.h */
 127 static void cache_get_line_size(struct cacheinfo *this_leaf,
 128                                 struct device_node *np)
 129 {
 130         int i, lim, ct_idx;
 131
 132         ct_idx = get_cacheinfo_idx(this_leaf->type);
 133         lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
 134
 135         for (i = 0; i < lim; i++) {
 136                 int ret;
 137                 u32 line_size;
 138                 const char *propname;
 139
 140                 propname = cache_type_info[ct_idx].line_size_props[i];
 141                 ret = of_property_read_u32(np, propname, &line_size);
 142                 if (!ret) {
 143                         this_leaf->coherency_line_size = line_size;
 144                         break;
 145                 }
 146         }
 147 }
 148
 149 static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
 150 {
 151         const char *propname;
 152         int ct_idx;
 153
 154         ct_idx = get_cacheinfo_idx(this_leaf->type);
 155         propname = cache_type_info[ct_idx].nr_sets_prop;
 156
 157         of_property_read_u32(np, propname, &this_leaf->number_of_sets);
 158 }
 159
 160 static void cache_associativity(struct cacheinfo *this_leaf)
 161 {
 162         unsigned int line_size = this_leaf->coherency_line_size;
 163         unsigned int nr_sets = this_leaf->number_of_sets;
 164         unsigned int size = this_leaf->size;
 165
 166         /*
 167          * If the cache is fully associative, there is no need to
 168          * check the other properties.
 169          */
 170         if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
 171                 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
 172 }
 173
 174 static bool cache_node_is_unified(struct cacheinfo *this_leaf,
 175                                   struct device_node *np)
 176 {
 177         return of_property_read_bool(np, "cache-unified");
 178 }
 179
 180 static void cache_of_set_props(struct cacheinfo *this_leaf,
 181                                struct device_node *np)
 182 {
 183         /*
 184          * init_cache_level must setup the cache level correctly
 185          * overriding the architecturally specified levels, so
 186          * if type is NONE at this stage, it should be unified
 187          */
 188         if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 189             cache_node_is_unified(this_leaf, np))
 190                 this_leaf->type = CACHE_TYPE_UNIFIED;
 191         cache_size(this_leaf, np);
 192         cache_get_line_size(this_leaf, np);
 193         cache_nr_sets(this_leaf, np);
 194         cache_associativity(this_leaf);
 195 }
 196
 197 static int cache_setup_of_node(unsigned int cpu)
 198 {
 199         struct device_node *np, *prev;
 200         struct cacheinfo *this_leaf;
 201         unsigned int index = 0;
 202
 203         np = of_cpu_device_node_get(cpu);
 204         if (!np) {
 205                 pr_err("Failed to find cpu%d device node\n", cpu);
 206                 return -ENOENT;
 207         }
 208
 209         prev = np;
 210
 211         while (index < cache_leaves(cpu)) {
 212                 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
 213                 if (this_leaf->level != 1) {
 214                         np = of_find_next_cache_node(np);
 215                         of_node_put(prev);
 216                         prev = np;
 217                         if (!np)
 218                                 break;
 219                 }
 220                 cache_of_set_props(this_leaf, np);
 221                 this_leaf->fw_token = np;
 222                 index++;
 223         }
 224
 225         of_node_put(np);
 226
 227         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
 228                 return -ENOENT;
 229
 230         return 0;
 231 }
 232 #else
 233 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 234 #endif
 235
 236 int __weak cache_setup_acpi(unsigned int cpu)
 237 {
 238         return -ENOTSUPP;
 239 }
 240
 241 unsigned int coherency_max_size;
 242
 243 static int cache_setup_properties(unsigned int cpu)
 244 {
 245         int ret = 0;
 246
 247         if (of_have_populated_dt())
 248                 ret = cache_setup_of_node(cpu);
 249         else if (!acpi_disabled)
 250                 ret = cache_setup_acpi(cpu);
 251
 252         return ret;
 253 }
 254
 255 static int cache_shared_cpu_map_setup(unsigned int cpu)
 256 {
 257         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 258         struct cacheinfo *this_leaf, *sib_leaf;
 259         unsigned int index;
 260         int ret = 0;
 261
 262         if (this_cpu_ci->cpu_map_populated)
 263                 return 0;
 264
 265         /*
 266          * skip setting up cache properties if LLC is valid, just need
 267          * to update the shared cpu_map if the cache attributes were
 268          * populated early before all the cpus are brought online
 269          */
 270         if (!last_level_cache_is_valid(cpu)) {
 271                 ret = cache_setup_properties(cpu);
 272                 if (ret)
 273                         return ret;
 274         }
 275
 276         for (index = 0; index < cache_leaves(cpu); index++) {
 277                 unsigned int i;
 278
 279                 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
 280
 281                 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
 282                 for_each_online_cpu(i) {
 283                         struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
 284
 285                         if (i == cpu || !sib_cpu_ci->info_list)
 286                                 continue;/* skip if itself or no cacheinfo */
 287
 288                         sib_leaf = per_cpu_cacheinfo_idx(i, index);
 289                         if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 290                                 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
 291                                 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
 292                         }
 293                 }
 294                 /* record the maximum cache line size */
 295                 if (this_leaf->coherency_line_size > coherency_max_size)
 296                         coherency_max_size = this_leaf->coherency_line_size;
 297         }
 298
 299         return 0;
 300 }
 301
 302 static void cache_shared_cpu_map_remove(unsigned int cpu)
 303 {
 304         struct cacheinfo *this_leaf, *sib_leaf;
 305         unsigned int sibling, index;
 306
 307         for (index = 0; index < cache_leaves(cpu); index++) {
 308                 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
 309                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 310                         struct cpu_cacheinfo *sib_cpu_ci =
 311                                                 get_cpu_cacheinfo(sibling);
 312
 313                         if (sibling == cpu || !sib_cpu_ci->info_list)
 314                                 continue;/* skip if itself or no cacheinfo */
 315
 316                         sib_leaf = per_cpu_cacheinfo_idx(sibling, index);
 317                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 318                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 319                 }
 320                 if (of_have_populated_dt())
 321                         of_node_put(this_leaf->fw_token);
 322         }
 323 }
 324
 325 static void free_cache_attributes(unsigned int cpu)
 326 {
 327         if (!per_cpu_cacheinfo(cpu))
 328                 return;
 329
 330         cache_shared_cpu_map_remove(cpu);
 331
 332         kfree(per_cpu_cacheinfo(cpu));
 333         per_cpu_cacheinfo(cpu) = NULL;
 334         cache_leaves(cpu) = 0;
 335 }
 336
 337 int __weak init_cache_level(unsigned int cpu)
 338 {
 339         return -ENOENT;
 340 }
 341
 342 int __weak populate_cache_leaves(unsigned int cpu)
 343 {
 344         return -ENOENT;
 345 }
 346
 347 int detect_cache_attributes(unsigned int cpu)
 348 {
 349         int ret;
 350
 351         /* Since early detection of the cacheinfo is allowed via this
 352          * function and this also gets called as CPU hotplug callbacks via
 353          * cacheinfo_cpu_online, the initialisation can be skipped and only
 354          * CPU maps can be updated as the CPU online status would be update
 355          * if called via cacheinfo_cpu_online path.
 356          */
 357         if (per_cpu_cacheinfo(cpu))
 358                 goto update_cpu_map;
 359
 360         if (init_cache_level(cpu) || !cache_leaves(cpu))
 361                 return -ENOENT;
 362
 363         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 364                                          sizeof(struct cacheinfo), GFP_ATOMIC);
 365         if (per_cpu_cacheinfo(cpu) == NULL) {
 366                 cache_leaves(cpu) = 0;
 367                 return -ENOMEM;
 368         }
 369
 370         /*
 371          * populate_cache_leaves() may completely setup the cache leaves and
 372          * shared_cpu_map or it may leave it partially setup.
 373          */
 374         ret = populate_cache_leaves(cpu);
 375         if (ret)
 376                 goto free_ci;
 377
 378 update_cpu_map:
 379         /*
 380          * For systems using DT for cache hierarchy, fw_token
 381          * and shared_cpu_map will be set up here only if they are
 382          * not populated already
 383          */
 384         ret = cache_shared_cpu_map_setup(cpu);
 385         if (ret) {
 386                 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
 387                 goto free_ci;
 388         }
 389
 390         return 0;
 391
 392 free_ci:
 393         free_cache_attributes(cpu);
 394         return ret;
 395 }
 396
 397 /* pointer to cpuX/cache device */
 398 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 399 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 400
 401 static cpumask_t cache_dev_map;
 402
 403 /* pointer to array of devices for cpuX/cache/indexY */
 404 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 405 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 406 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 407
 408 #define show_one(file_name, object)                             \
 409 static ssize_t file_name##_show(struct device *dev,             \
 410                 struct device_attribute *attr, char *buf)       \
 411 {                                                               \
 412         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 413         return sysfs_emit(buf, "%u\n", this_leaf->object);      \
 414 }
 415
 416 show_one(id, id);
 417 show_one(level, level);
 418 show_one(coherency_line_size, coherency_line_size);
 419 show_one(number_of_sets, number_of_sets);
 420 show_one(physical_line_partition, physical_line_partition);
 421 show_one(ways_of_associativity, ways_of_associativity);
 422
 423 static ssize_t size_show(struct device *dev,
 424                          struct device_attribute *attr, char *buf)
 425 {
 426         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 427
 428         return sysfs_emit(buf, "%uK\n", this_leaf->size >> 10);
 429 }
 430
 431 static ssize_t shared_cpu_map_show(struct device *dev,
 432                                    struct device_attribute *attr, char *buf)
 433 {
 434         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 435         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 436
 437         return sysfs_emit(buf, "%*pb\n", nr_cpu_ids, mask);
 438 }
 439
 440 static ssize_t shared_cpu_list_show(struct device *dev,
 441                                     struct device_attribute *attr, char *buf)
 442 {
 443         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 444         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 445
 446         return sysfs_emit(buf, "%*pbl\n", nr_cpu_ids, mask);
 447 }
 448
 449 static ssize_t type_show(struct device *dev,
 450                          struct device_attribute *attr, char *buf)
 451 {
 452         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 453         const char *output;
 454
 455         switch (this_leaf->type) {
 456         case CACHE_TYPE_DATA:
 457                 output = "Data";
 458                 break;
 459         case CACHE_TYPE_INST:
 460                 output = "Instruction";
 461                 break;
 462         case CACHE_TYPE_UNIFIED:
 463                 output = "Unified";
 464                 break;
 465         default:
 466                 return -EINVAL;
 467         }
 468
 469         return sysfs_emit(buf, "%s\n", output);
 470 }
 471
 472 static ssize_t allocation_policy_show(struct device *dev,
 473                                       struct device_attribute *attr, char *buf)
 474 {
 475         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 476         unsigned int ci_attr = this_leaf->attributes;
 477         const char *output;
 478
 479         if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
 480                 output = "ReadWriteAllocate";
 481         else if (ci_attr & CACHE_READ_ALLOCATE)
 482                 output = "ReadAllocate";
 483         else if (ci_attr & CACHE_WRITE_ALLOCATE)
 484                 output = "WriteAllocate";
 485         else
 486                 return 0;
 487
 488         return sysfs_emit(buf, "%s\n", output);
 489 }
 490
 491 static ssize_t write_policy_show(struct device *dev,
 492                                  struct device_attribute *attr, char *buf)
 493 {
 494         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 495         unsigned int ci_attr = this_leaf->attributes;
 496         int n = 0;
 497
 498         if (ci_attr & CACHE_WRITE_THROUGH)
 499                 n = sysfs_emit(buf, "WriteThrough\n");
 500         else if (ci_attr & CACHE_WRITE_BACK)
 501                 n = sysfs_emit(buf, "WriteBack\n");
 502         return n;
 503 }
 504
 505 static DEVICE_ATTR_RO(id);
 506 static DEVICE_ATTR_RO(level);
 507 static DEVICE_ATTR_RO(type);
 508 static DEVICE_ATTR_RO(coherency_line_size);
 509 static DEVICE_ATTR_RO(ways_of_associativity);
 510 static DEVICE_ATTR_RO(number_of_sets);
 511 static DEVICE_ATTR_RO(size);
 512 static DEVICE_ATTR_RO(allocation_policy);
 513 static DEVICE_ATTR_RO(write_policy);
 514 static DEVICE_ATTR_RO(shared_cpu_map);
 515 static DEVICE_ATTR_RO(shared_cpu_list);
 516 static DEVICE_ATTR_RO(physical_line_partition);
 517
 518 static struct attribute *cache_default_attrs[] = {
 519         &dev_attr_id.attr,
 520         &dev_attr_type.attr,
 521         &dev_attr_level.attr,
 522         &dev_attr_shared_cpu_map.attr,
 523         &dev_attr_shared_cpu_list.attr,
 524         &dev_attr_coherency_line_size.attr,
 525         &dev_attr_ways_of_associativity.attr,
 526         &dev_attr_number_of_sets.attr,
 527         &dev_attr_size.attr,
 528         &dev_attr_allocation_policy.attr,
 529         &dev_attr_write_policy.attr,
 530         &dev_attr_physical_line_partition.attr,
 531         NULL
 532 };
 533
 534 static umode_t
 535 cache_default_attrs_is_visible(struct kobject *kobj,
 536                                struct attribute *attr, int unused)
 537 {
 538         struct device *dev = kobj_to_dev(kobj);
 539         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 540         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 541         umode_t mode = attr->mode;
 542
 543         if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
 544                 return mode;
 545         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 546                 return mode;
 547         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 548                 return mode;
 549         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 550                 return mode;
 551         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 552                 return mode;
 553         if ((attr == &dev_attr_coherency_line_size.attr) &&
 554             this_leaf->coherency_line_size)
 555                 return mode;
 556         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 557             this_leaf->size) /* allow 0 = full associativity */
 558                 return mode;
 559         if ((attr == &dev_attr_number_of_sets.attr) &&
 560             this_leaf->number_of_sets)
 561                 return mode;
 562         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 563                 return mode;
 564         if ((attr == &dev_attr_write_policy.attr) &&
 565             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 566                 return mode;
 567         if ((attr == &dev_attr_allocation_policy.attr) &&
 568             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 569                 return mode;
 570         if ((attr == &dev_attr_physical_line_partition.attr) &&
 571             this_leaf->physical_line_partition)
 572                 return mode;
 573
 574         return 0;
 575 }
 576
 577 static const struct attribute_group cache_default_group = {
 578         .attrs = cache_default_attrs,
 579         .is_visible = cache_default_attrs_is_visible,
 580 };
 581
 582 static const struct attribute_group *cache_default_groups[] = {
 583         &cache_default_group,
 584         NULL,
 585 };
 586
 587 static const struct attribute_group *cache_private_groups[] = {
 588         &cache_default_group,
 589         NULL, /* Place holder for private group */
 590         NULL,
 591 };
 592
 593 const struct attribute_group *
 594 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 595 {
 596         return NULL;
 597 }
 598
 599 static const struct attribute_group **
 600 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 601 {
 602         const struct attribute_group *priv_group =
 603                         cache_get_priv_group(this_leaf);
 604
 605         if (!priv_group)
 606                 return cache_default_groups;
 607
 608         if (!cache_private_groups[1])
 609                 cache_private_groups[1] = priv_group;
 610
 611         return cache_private_groups;
 612 }
 613
 614 /* Add/Remove cache interface for CPU device */
 615 static void cpu_cache_sysfs_exit(unsigned int cpu)
 616 {
 617         int i;
 618         struct device *ci_dev;
 619
 620         if (per_cpu_index_dev(cpu)) {
 621                 for (i = 0; i < cache_leaves(cpu); i++) {
 622                         ci_dev = per_cache_index_dev(cpu, i);
 623                         if (!ci_dev)
 624                                 continue;
 625                         device_unregister(ci_dev);
 626                 }
 627                 kfree(per_cpu_index_dev(cpu));
 628                 per_cpu_index_dev(cpu) = NULL;
 629         }
 630         device_unregister(per_cpu_cache_dev(cpu));
 631         per_cpu_cache_dev(cpu) = NULL;
 632 }
 633
 634 static int cpu_cache_sysfs_init(unsigned int cpu)
 635 {
 636         struct device *dev = get_cpu_device(cpu);
 637
 638         if (per_cpu_cacheinfo(cpu) == NULL)
 639                 return -ENOENT;
 640
 641         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 642         if (IS_ERR(per_cpu_cache_dev(cpu)))
 643                 return PTR_ERR(per_cpu_cache_dev(cpu));
 644
 645         /* Allocate all required memory */
 646         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 647                                          sizeof(struct device *), GFP_KERNEL);
 648         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 649                 goto err_out;
 650
 651         return 0;
 652
 653 err_out:
 654         cpu_cache_sysfs_exit(cpu);
 655         return -ENOMEM;
 656 }
 657
 658 static int cache_add_dev(unsigned int cpu)
 659 {
 660         unsigned int i;
 661         int rc;
 662         struct device *ci_dev, *parent;
 663         struct cacheinfo *this_leaf;
 664         const struct attribute_group **cache_groups;
 665
 666         rc = cpu_cache_sysfs_init(cpu);
 667         if (unlikely(rc < 0))
 668                 return rc;
 669
 670         parent = per_cpu_cache_dev(cpu);
 671         for (i = 0; i < cache_leaves(cpu); i++) {
 672                 this_leaf = per_cpu_cacheinfo_idx(cpu, i);
 673                 if (this_leaf->disable_sysfs)
 674                         continue;
 675                 if (this_leaf->type == CACHE_TYPE_NOCACHE)
 676                         break;
 677                 cache_groups = cache_get_attribute_groups(this_leaf);
 678                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 679                                            "index%1u", i);
 680                 if (IS_ERR(ci_dev)) {
 681                         rc = PTR_ERR(ci_dev);
 682                         goto err;
 683                 }
 684                 per_cache_index_dev(cpu, i) = ci_dev;
 685         }
 686         cpumask_set_cpu(cpu, &cache_dev_map);
 687
 688         return 0;
 689 err:
 690         cpu_cache_sysfs_exit(cpu);
 691         return rc;
 692 }
 693
 694 static int cacheinfo_cpu_online(unsigned int cpu)
 695 {
 696         int rc = detect_cache_attributes(cpu);
 697
 698         if (rc)
 699                 return rc;
 700         rc = cache_add_dev(cpu);
 701         if (rc)
 702                 free_cache_attributes(cpu);
 703         return rc;
 704 }
 705
 706 static int cacheinfo_cpu_pre_down(unsigned int cpu)
 707 {
 708         if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
 709                 cpu_cache_sysfs_exit(cpu);
 710
 711         free_cache_attributes(cpu);
 712         return 0;
 713 }
 714
 715 static int __init cacheinfo_sysfs_init(void)
 716 {
 717         return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
 718                                  "base/cacheinfo:online",
 719                                  cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 720 }
 721 device_initcall(cacheinfo_sysfs_init);