drivers/base/cacheinfo.c

   1 /*
   2  * cacheinfo support - processor cache information via sysfs
   3  *
   4  * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
   5  * Author: Sudeep Holla <sudeep.holla@arm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  12  * kind, whether express or implied; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  20
  21 #include <linux/acpi.h>
  22 #include <linux/bitops.h>
  23 #include <linux/cacheinfo.h>
  24 #include <linux/compiler.h>
  25 #include <linux/cpu.h>
  26 #include <linux/device.h>
  27 #include <linux/init.h>
  28 #include <linux/of.h>
  29 #include <linux/sched.h>
  30 #include <linux/slab.h>
  31 #include <linux/smp.h>
  32 #include <linux/sysfs.h>
  33
  34 /* pointer to per cpu cacheinfo */
  35 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
  36 #define ci_cacheinfo(cpu)       (&per_cpu(ci_cpu_cacheinfo, cpu))
  37 #define cache_leaves(cpu)       (ci_cacheinfo(cpu)->num_leaves)
  38 #define per_cpu_cacheinfo(cpu)  (ci_cacheinfo(cpu)->info_list)
  39
  40 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
  41 {
  42         return ci_cacheinfo(cpu);
  43 }
  44
  45 #ifdef CONFIG_OF
  46 static int cache_setup_of_node(unsigned int cpu)
  47 {
  48         struct device_node *np;
  49         struct cacheinfo *this_leaf;
  50         struct device *cpu_dev = get_cpu_device(cpu);
  51         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
  52         unsigned int index = 0;
  53
  54         /* skip if of_node is already populated */
  55         if (this_cpu_ci->info_list->of_node)
  56                 return 0;
  57
  58         if (!cpu_dev) {
  59                 pr_err("No cpu device for CPU %d\n", cpu);
  60                 return -ENODEV;
  61         }
  62         np = cpu_dev->of_node;
  63         if (!np) {
  64                 pr_err("Failed to find cpu%d device node\n", cpu);
  65                 return -ENOENT;
  66         }
  67
  68         while (index < cache_leaves(cpu)) {
  69                 this_leaf = this_cpu_ci->info_list + index;
  70                 if (this_leaf->level != 1)
  71                         np = of_find_next_cache_node(np);
  72                 else
  73                         np = of_node_get(np);/* cpu node itself */
  74                 if (!np)
  75                         break;
  76                 this_leaf->of_node = np;
  77                 index++;
  78         }
  79
  80         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
  81                 return -ENOENT;
  82
  83         return 0;
  84 }
  85
  86 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  87                                            struct cacheinfo *sib_leaf)
  88 {
  89         return sib_leaf->of_node == this_leaf->of_node;
  90 }
  91
  92 /* OF properties to query for a given cache type */
  93 struct cache_type_info {
  94         const char *size_prop;
  95         const char *line_size_props[2];
  96         const char *nr_sets_prop;
  97 };
  98
  99 static const struct cache_type_info cache_type_info[] = {
 100         {
 101                 .size_prop       = "cache-size",
 102                 .line_size_props = { "cache-line-size",
 103                                      "cache-block-size", },
 104                 .nr_sets_prop    = "cache-sets",
 105         }, {
 106                 .size_prop       = "i-cache-size",
 107                 .line_size_props = { "i-cache-line-size",
 108                                      "i-cache-block-size", },
 109                 .nr_sets_prop    = "i-cache-sets",
 110         }, {
 111                 .size_prop       = "d-cache-size",
 112                 .line_size_props = { "d-cache-line-size",
 113                                      "d-cache-block-size", },
 114                 .nr_sets_prop    = "d-cache-sets",
 115         },
 116 };
 117
 118 static inline int get_cacheinfo_idx(enum cache_type type)
 119 {
 120         if (type == CACHE_TYPE_UNIFIED)
 121                 return 0;
 122         return type;
 123 }
 124
 125 static void cache_size(struct cacheinfo *this_leaf)
 126 {
 127         const char *propname;
 128         const __be32 *cache_size;
 129         int ct_idx;
 130
 131         ct_idx = get_cacheinfo_idx(this_leaf->type);
 132         propname = cache_type_info[ct_idx].size_prop;
 133
 134         cache_size = of_get_property(this_leaf->of_node, propname, NULL);
 135         if (cache_size)
 136                 this_leaf->size = of_read_number(cache_size, 1);
 137 }
 138
 139 /* not cache_line_size() because that's a macro in include/linux/cache.h */
 140 static void cache_get_line_size(struct cacheinfo *this_leaf)
 141 {
 142         const __be32 *line_size;
 143         int i, lim, ct_idx;
 144
 145         ct_idx = get_cacheinfo_idx(this_leaf->type);
 146         lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
 147
 148         for (i = 0; i < lim; i++) {
 149                 const char *propname;
 150
 151                 propname = cache_type_info[ct_idx].line_size_props[i];
 152                 line_size = of_get_property(this_leaf->of_node, propname, NULL);
 153                 if (line_size)
 154                         break;
 155         }
 156
 157         if (line_size)
 158                 this_leaf->coherency_line_size = of_read_number(line_size, 1);
 159 }
 160
 161 static void cache_nr_sets(struct cacheinfo *this_leaf)
 162 {
 163         const char *propname;
 164         const __be32 *nr_sets;
 165         int ct_idx;
 166
 167         ct_idx = get_cacheinfo_idx(this_leaf->type);
 168         propname = cache_type_info[ct_idx].nr_sets_prop;
 169
 170         nr_sets = of_get_property(this_leaf->of_node, propname, NULL);
 171         if (nr_sets)
 172                 this_leaf->number_of_sets = of_read_number(nr_sets, 1);
 173 }
 174
 175 static void cache_associativity(struct cacheinfo *this_leaf)
 176 {
 177         unsigned int line_size = this_leaf->coherency_line_size;
 178         unsigned int nr_sets = this_leaf->number_of_sets;
 179         unsigned int size = this_leaf->size;
 180
 181         /*
 182          * If the cache is fully associative, there is no need to
 183          * check the other properties.
 184          */
 185         if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
 186                 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
 187 }
 188
 189 static void cache_of_override_properties(unsigned int cpu)
 190 {
 191         int index;
 192         struct cacheinfo *this_leaf;
 193         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 194
 195         for (index = 0; index < cache_leaves(cpu); index++) {
 196                 this_leaf = this_cpu_ci->info_list + index;
 197                 cache_size(this_leaf);
 198                 cache_get_line_size(this_leaf);
 199                 cache_nr_sets(this_leaf);
 200                 cache_associativity(this_leaf);
 201         }
 202 }
 203 #else
 204 static void cache_of_override_properties(unsigned int cpu) { }
 205 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 206 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
 207                                            struct cacheinfo *sib_leaf)
 208 {
 209         /*
 210          * For non-DT systems, assume unique level 1 cache, system-wide
 211          * shared caches for all other levels. This will be used only if
 212          * arch specific code has not populated shared_cpu_map
 213          */
 214         return !(this_leaf->level == 1);
 215 }
 216 #endif
 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                 /* No cache property/hierarchy support yet in ACPI */
 232                 ret = -ENOTSUPP;
 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                 of_node_put(this_leaf->of_node);
 284         }
 285 }
 286
 287 static void cache_override_properties(unsigned int cpu)
 288 {
 289         if (of_have_populated_dt())
 290                 return cache_of_override_properties(cpu);
 291 }
 292
 293 static void free_cache_attributes(unsigned int cpu)
 294 {
 295         if (!per_cpu_cacheinfo(cpu))
 296                 return;
 297
 298         cache_shared_cpu_map_remove(cpu);
 299
 300         kfree(per_cpu_cacheinfo(cpu));
 301         per_cpu_cacheinfo(cpu) = NULL;
 302 }
 303
 304 int __weak init_cache_level(unsigned int cpu)
 305 {
 306         return -ENOENT;
 307 }
 308
 309 int __weak populate_cache_leaves(unsigned int cpu)
 310 {
 311         return -ENOENT;
 312 }
 313
 314 static int detect_cache_attributes(unsigned int cpu)
 315 {
 316         int ret;
 317
 318         if (init_cache_level(cpu) || !cache_leaves(cpu))
 319                 return -ENOENT;
 320
 321         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 322                                          sizeof(struct cacheinfo), GFP_KERNEL);
 323         if (per_cpu_cacheinfo(cpu) == NULL)
 324                 return -ENOMEM;
 325
 326         ret = populate_cache_leaves(cpu);
 327         if (ret)
 328                 goto free_ci;
 329         /*
 330          * For systems using DT for cache hierarchy, of_node and shared_cpu_map
 331          * will be set up here only if they are 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         cache_override_properties(cpu);
 340         return 0;
 341
 342 free_ci:
 343         free_cache_attributes(cpu);
 344         return ret;
 345 }
 346
 347 /* pointer to cpuX/cache device */
 348 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 349 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 350
 351 static cpumask_t cache_dev_map;
 352
 353 /* pointer to array of devices for cpuX/cache/indexY */
 354 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 355 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 356 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 357
 358 #define show_one(file_name, object)                             \
 359 static ssize_t file_name##_show(struct device *dev,             \
 360                 struct device_attribute *attr, char *buf)       \
 361 {                                                               \
 362         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 363         return sprintf(buf, "%u\n", this_leaf->object);         \
 364 }
 365
 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(level);
 448 static DEVICE_ATTR_RO(type);
 449 static DEVICE_ATTR_RO(coherency_line_size);
 450 static DEVICE_ATTR_RO(ways_of_associativity);
 451 static DEVICE_ATTR_RO(number_of_sets);
 452 static DEVICE_ATTR_RO(size);
 453 static DEVICE_ATTR_RO(allocation_policy);
 454 static DEVICE_ATTR_RO(write_policy);
 455 static DEVICE_ATTR_RO(shared_cpu_map);
 456 static DEVICE_ATTR_RO(shared_cpu_list);
 457 static DEVICE_ATTR_RO(physical_line_partition);
 458
 459 static struct attribute *cache_default_attrs[] = {
 460         &dev_attr_type.attr,
 461         &dev_attr_level.attr,
 462         &dev_attr_shared_cpu_map.attr,
 463         &dev_attr_shared_cpu_list.attr,
 464         &dev_attr_coherency_line_size.attr,
 465         &dev_attr_ways_of_associativity.attr,
 466         &dev_attr_number_of_sets.attr,
 467         &dev_attr_size.attr,
 468         &dev_attr_allocation_policy.attr,
 469         &dev_attr_write_policy.attr,
 470         &dev_attr_physical_line_partition.attr,
 471         NULL
 472 };
 473
 474 static umode_t
 475 cache_default_attrs_is_visible(struct kobject *kobj,
 476                                struct attribute *attr, int unused)
 477 {
 478         struct device *dev = kobj_to_dev(kobj);
 479         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 480         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 481         umode_t mode = attr->mode;
 482
 483         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 484                 return mode;
 485         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 486                 return mode;
 487         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 488                 return mode;
 489         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 490                 return mode;
 491         if ((attr == &dev_attr_coherency_line_size.attr) &&
 492             this_leaf->coherency_line_size)
 493                 return mode;
 494         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 495             this_leaf->size) /* allow 0 = full associativity */
 496                 return mode;
 497         if ((attr == &dev_attr_number_of_sets.attr) &&
 498             this_leaf->number_of_sets)
 499                 return mode;
 500         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 501                 return mode;
 502         if ((attr == &dev_attr_write_policy.attr) &&
 503             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 504                 return mode;
 505         if ((attr == &dev_attr_allocation_policy.attr) &&
 506             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 507                 return mode;
 508         if ((attr == &dev_attr_physical_line_partition.attr) &&
 509             this_leaf->physical_line_partition)
 510                 return mode;
 511
 512         return 0;
 513 }
 514
 515 static const struct attribute_group cache_default_group = {
 516         .attrs = cache_default_attrs,
 517         .is_visible = cache_default_attrs_is_visible,
 518 };
 519
 520 static const struct attribute_group *cache_default_groups[] = {
 521         &cache_default_group,
 522         NULL,
 523 };
 524
 525 static const struct attribute_group *cache_private_groups[] = {
 526         &cache_default_group,
 527         NULL, /* Place holder for private group */
 528         NULL,
 529 };
 530
 531 const struct attribute_group *
 532 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 533 {
 534         return NULL;
 535 }
 536
 537 static const struct attribute_group **
 538 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 539 {
 540         const struct attribute_group *priv_group =
 541                         cache_get_priv_group(this_leaf);
 542
 543         if (!priv_group)
 544                 return cache_default_groups;
 545
 546         if (!cache_private_groups[1])
 547                 cache_private_groups[1] = priv_group;
 548
 549         return cache_private_groups;
 550 }
 551
 552 /* Add/Remove cache interface for CPU device */
 553 static void cpu_cache_sysfs_exit(unsigned int cpu)
 554 {
 555         int i;
 556         struct device *ci_dev;
 557
 558         if (per_cpu_index_dev(cpu)) {
 559                 for (i = 0; i < cache_leaves(cpu); i++) {
 560                         ci_dev = per_cache_index_dev(cpu, i);
 561                         if (!ci_dev)
 562                                 continue;
 563                         device_unregister(ci_dev);
 564                 }
 565                 kfree(per_cpu_index_dev(cpu));
 566                 per_cpu_index_dev(cpu) = NULL;
 567         }
 568         device_unregister(per_cpu_cache_dev(cpu));
 569         per_cpu_cache_dev(cpu) = NULL;
 570 }
 571
 572 static int cpu_cache_sysfs_init(unsigned int cpu)
 573 {
 574         struct device *dev = get_cpu_device(cpu);
 575
 576         if (per_cpu_cacheinfo(cpu) == NULL)
 577                 return -ENOENT;
 578
 579         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 580         if (IS_ERR(per_cpu_cache_dev(cpu)))
 581                 return PTR_ERR(per_cpu_cache_dev(cpu));
 582
 583         /* Allocate all required memory */
 584         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 585                                          sizeof(struct device *), GFP_KERNEL);
 586         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 587                 goto err_out;
 588
 589         return 0;
 590
 591 err_out:
 592         cpu_cache_sysfs_exit(cpu);
 593         return -ENOMEM;
 594 }
 595
 596 static int cache_add_dev(unsigned int cpu)
 597 {
 598         unsigned int i;
 599         int rc;
 600         struct device *ci_dev, *parent;
 601         struct cacheinfo *this_leaf;
 602         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 603         const struct attribute_group **cache_groups;
 604
 605         rc = cpu_cache_sysfs_init(cpu);
 606         if (unlikely(rc < 0))
 607                 return rc;
 608
 609         parent = per_cpu_cache_dev(cpu);
 610         for (i = 0; i < cache_leaves(cpu); i++) {
 611                 this_leaf = this_cpu_ci->info_list + i;
 612                 if (this_leaf->disable_sysfs)
 613                         continue;
 614                 cache_groups = cache_get_attribute_groups(this_leaf);
 615                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 616                                            "index%1u", i);
 617                 if (IS_ERR(ci_dev)) {
 618                         rc = PTR_ERR(ci_dev);
 619                         goto err;
 620                 }
 621                 per_cache_index_dev(cpu, i) = ci_dev;
 622         }
 623         cpumask_set_cpu(cpu, &cache_dev_map);
 624
 625         return 0;
 626 err:
 627         cpu_cache_sysfs_exit(cpu);
 628         return rc;
 629 }
 630
 631 static void cache_remove_dev(unsigned int cpu)
 632 {
 633         if (!cpumask_test_cpu(cpu, &cache_dev_map))
 634                 return;
 635         cpumask_clear_cpu(cpu, &cache_dev_map);
 636
 637         cpu_cache_sysfs_exit(cpu);
 638 }
 639
 640 static int cacheinfo_cpu_callback(struct notifier_block *nfb,
 641                                   unsigned long action, void *hcpu)
 642 {
 643         unsigned int cpu = (unsigned long)hcpu;
 644         int rc = 0;
 645
 646         switch (action & ~CPU_TASKS_FROZEN) {
 647         case CPU_ONLINE:
 648                 rc = detect_cache_attributes(cpu);
 649                 if (!rc)
 650                         rc = cache_add_dev(cpu);
 651                 break;
 652         case CPU_DEAD:
 653                 cache_remove_dev(cpu);
 654                 free_cache_attributes(cpu);
 655                 break;
 656         }
 657         return notifier_from_errno(rc);
 658 }
 659
 660 static int __init cacheinfo_sysfs_init(void)
 661 {
 662         int cpu, rc = 0;
 663
 664         cpu_notifier_register_begin();
 665
 666         for_each_online_cpu(cpu) {
 667                 rc = detect_cache_attributes(cpu);
 668                 if (rc)
 669                         goto out;
 670                 rc = cache_add_dev(cpu);
 671                 if (rc) {
 672                         free_cache_attributes(cpu);
 673                         pr_err("error populating cacheinfo..cpu%d\n", cpu);
 674                         goto out;
 675                 }
 676         }
 677         __hotcpu_notifier(cacheinfo_cpu_callback, 0);
 678
 679 out:
 680         cpu_notifier_register_done();
 681         return rc;
 682 }
 683
 684 device_initcall(cacheinfo_sysfs_init);