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 #include <linux/acpi.h>
  20 #include <linux/bitops.h>
  21 #include <linux/cacheinfo.h>
  22 #include <linux/compiler.h>
  23 #include <linux/cpu.h>
  24 #include <linux/device.h>
  25 #include <linux/init.h>
  26 #include <linux/of.h>
  27 #include <linux/sched.h>
  28 #include <linux/slab.h>
  29 #include <linux/smp.h>
  30 #include <linux/sysfs.h>
  31
  32 /* pointer to per cpu cacheinfo */
  33 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
  34 #define ci_cacheinfo(cpu)       (&per_cpu(ci_cpu_cacheinfo, cpu))
  35 #define cache_leaves(cpu)       (ci_cacheinfo(cpu)->num_leaves)
  36 #define per_cpu_cacheinfo(cpu)  (ci_cacheinfo(cpu)->info_list)
  37
  38 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
  39 {
  40         return ci_cacheinfo(cpu);
  41 }
  42
  43 #ifdef CONFIG_OF
  44 static int cache_setup_of_node(unsigned int cpu)
  45 {
  46         struct device_node *np;
  47         struct cacheinfo *this_leaf;
  48         struct device *cpu_dev = get_cpu_device(cpu);
  49         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
  50         unsigned int index = 0;
  51
  52         /* skip if of_node is already populated */
  53         if (this_cpu_ci->info_list->of_node)
  54                 return 0;
  55
  56         if (!cpu_dev) {
  57                 pr_err("No cpu device for CPU %d\n", cpu);
  58                 return -ENODEV;
  59         }
  60         np = cpu_dev->of_node;
  61         if (!np) {
  62                 pr_err("Failed to find cpu%d device node\n", cpu);
  63                 return -ENOENT;
  64         }
  65
  66         while (index < cache_leaves(cpu)) {
  67                 this_leaf = this_cpu_ci->info_list + index;
  68                 if (this_leaf->level != 1)
  69                         np = of_find_next_cache_node(np);
  70                 else
  71                         np = of_node_get(np);/* cpu node itself */
  72                 if (!np)
  73                         break;
  74                 this_leaf->of_node = np;
  75                 index++;
  76         }
  77
  78         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
  79                 return -ENOENT;
  80
  81         return 0;
  82 }
  83
  84 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  85                                            struct cacheinfo *sib_leaf)
  86 {
  87         return sib_leaf->of_node == this_leaf->of_node;
  88 }
  89 #else
  90 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
  91 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  92                                            struct cacheinfo *sib_leaf)
  93 {
  94         /*
  95          * For non-DT systems, assume unique level 1 cache, system-wide
  96          * shared caches for all other levels. This will be used only if
  97          * arch specific code has not populated shared_cpu_map
  98          */
  99         return !(this_leaf->level == 1);
 100 }
 101 #endif
 102
 103 static int cache_shared_cpu_map_setup(unsigned int cpu)
 104 {
 105         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 106         struct cacheinfo *this_leaf, *sib_leaf;
 107         unsigned int index;
 108         int ret = 0;
 109
 110         if (this_cpu_ci->cpu_map_populated)
 111                 return 0;
 112
 113         if (of_have_populated_dt())
 114                 ret = cache_setup_of_node(cpu);
 115         else if (!acpi_disabled)
 116                 /* No cache property/hierarchy support yet in ACPI */
 117                 ret = -ENOTSUPP;
 118         if (ret)
 119                 return ret;
 120
 121         for (index = 0; index < cache_leaves(cpu); index++) {
 122                 unsigned int i;
 123
 124                 this_leaf = this_cpu_ci->info_list + index;
 125                 /* skip if shared_cpu_map is already populated */
 126                 if (!cpumask_empty(&this_leaf->shared_cpu_map))
 127                         continue;
 128
 129                 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
 130                 for_each_online_cpu(i) {
 131                         struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
 132
 133                         if (i == cpu || !sib_cpu_ci->info_list)
 134                                 continue;/* skip if itself or no cacheinfo */
 135                         sib_leaf = sib_cpu_ci->info_list + index;
 136                         if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 137                                 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
 138                                 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
 139                         }
 140                 }
 141         }
 142
 143         return 0;
 144 }
 145
 146 static void cache_shared_cpu_map_remove(unsigned int cpu)
 147 {
 148         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 149         struct cacheinfo *this_leaf, *sib_leaf;
 150         unsigned int sibling, index;
 151
 152         for (index = 0; index < cache_leaves(cpu); index++) {
 153                 this_leaf = this_cpu_ci->info_list + index;
 154                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 155                         struct cpu_cacheinfo *sib_cpu_ci;
 156
 157                         if (sibling == cpu) /* skip itself */
 158                                 continue;
 159
 160                         sib_cpu_ci = get_cpu_cacheinfo(sibling);
 161                         if (!sib_cpu_ci->info_list)
 162                                 continue;
 163
 164                         sib_leaf = sib_cpu_ci->info_list + index;
 165                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 166                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 167                 }
 168                 of_node_put(this_leaf->of_node);
 169         }
 170 }
 171
 172 static void free_cache_attributes(unsigned int cpu)
 173 {
 174         if (!per_cpu_cacheinfo(cpu))
 175                 return;
 176
 177         cache_shared_cpu_map_remove(cpu);
 178
 179         kfree(per_cpu_cacheinfo(cpu));
 180         per_cpu_cacheinfo(cpu) = NULL;
 181 }
 182
 183 int __weak init_cache_level(unsigned int cpu)
 184 {
 185         return -ENOENT;
 186 }
 187
 188 int __weak populate_cache_leaves(unsigned int cpu)
 189 {
 190         return -ENOENT;
 191 }
 192
 193 static int detect_cache_attributes(unsigned int cpu)
 194 {
 195         int ret;
 196
 197         if (init_cache_level(cpu) || !cache_leaves(cpu))
 198                 return -ENOENT;
 199
 200         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 201                                          sizeof(struct cacheinfo), GFP_KERNEL);
 202         if (per_cpu_cacheinfo(cpu) == NULL)
 203                 return -ENOMEM;
 204
 205         ret = populate_cache_leaves(cpu);
 206         if (ret)
 207                 goto free_ci;
 208         /*
 209          * For systems using DT for cache hierarchy, of_node and shared_cpu_map
 210          * will be set up here only if they are not populated already
 211          */
 212         ret = cache_shared_cpu_map_setup(cpu);
 213         if (ret) {
 214                 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
 215                 goto free_ci;
 216         }
 217         return 0;
 218
 219 free_ci:
 220         free_cache_attributes(cpu);
 221         return ret;
 222 }
 223
 224 /* pointer to cpuX/cache device */
 225 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 226 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 227
 228 static cpumask_t cache_dev_map;
 229
 230 /* pointer to array of devices for cpuX/cache/indexY */
 231 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 232 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 233 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 234
 235 #define show_one(file_name, object)                             \
 236 static ssize_t file_name##_show(struct device *dev,             \
 237                 struct device_attribute *attr, char *buf)       \
 238 {                                                               \
 239         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 240         return sprintf(buf, "%u\n", this_leaf->object);         \
 241 }
 242
 243 show_one(level, level);
 244 show_one(coherency_line_size, coherency_line_size);
 245 show_one(number_of_sets, number_of_sets);
 246 show_one(physical_line_partition, physical_line_partition);
 247 show_one(ways_of_associativity, ways_of_associativity);
 248
 249 static ssize_t size_show(struct device *dev,
 250                          struct device_attribute *attr, char *buf)
 251 {
 252         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 253
 254         return sprintf(buf, "%uK\n", this_leaf->size >> 10);
 255 }
 256
 257 static ssize_t shared_cpumap_show_func(struct device *dev, bool list, char *buf)
 258 {
 259         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 260         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 261
 262         return cpumap_print_to_pagebuf(list, buf, mask);
 263 }
 264
 265 static ssize_t shared_cpu_map_show(struct device *dev,
 266                                    struct device_attribute *attr, char *buf)
 267 {
 268         return shared_cpumap_show_func(dev, false, buf);
 269 }
 270
 271 static ssize_t shared_cpu_list_show(struct device *dev,
 272                                     struct device_attribute *attr, char *buf)
 273 {
 274         return shared_cpumap_show_func(dev, true, buf);
 275 }
 276
 277 static ssize_t type_show(struct device *dev,
 278                          struct device_attribute *attr, char *buf)
 279 {
 280         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 281
 282         switch (this_leaf->type) {
 283         case CACHE_TYPE_DATA:
 284                 return sprintf(buf, "Data\n");
 285         case CACHE_TYPE_INST:
 286                 return sprintf(buf, "Instruction\n");
 287         case CACHE_TYPE_UNIFIED:
 288                 return sprintf(buf, "Unified\n");
 289         default:
 290                 return -EINVAL;
 291         }
 292 }
 293
 294 static ssize_t allocation_policy_show(struct device *dev,
 295                                       struct device_attribute *attr, char *buf)
 296 {
 297         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 298         unsigned int ci_attr = this_leaf->attributes;
 299         int n = 0;
 300
 301         if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
 302                 n = sprintf(buf, "ReadWriteAllocate\n");
 303         else if (ci_attr & CACHE_READ_ALLOCATE)
 304                 n = sprintf(buf, "ReadAllocate\n");
 305         else if (ci_attr & CACHE_WRITE_ALLOCATE)
 306                 n = sprintf(buf, "WriteAllocate\n");
 307         return n;
 308 }
 309
 310 static ssize_t write_policy_show(struct device *dev,
 311                                  struct device_attribute *attr, char *buf)
 312 {
 313         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 314         unsigned int ci_attr = this_leaf->attributes;
 315         int n = 0;
 316
 317         if (ci_attr & CACHE_WRITE_THROUGH)
 318                 n = sprintf(buf, "WriteThrough\n");
 319         else if (ci_attr & CACHE_WRITE_BACK)
 320                 n = sprintf(buf, "WriteBack\n");
 321         return n;
 322 }
 323
 324 static DEVICE_ATTR_RO(level);
 325 static DEVICE_ATTR_RO(type);
 326 static DEVICE_ATTR_RO(coherency_line_size);
 327 static DEVICE_ATTR_RO(ways_of_associativity);
 328 static DEVICE_ATTR_RO(number_of_sets);
 329 static DEVICE_ATTR_RO(size);
 330 static DEVICE_ATTR_RO(allocation_policy);
 331 static DEVICE_ATTR_RO(write_policy);
 332 static DEVICE_ATTR_RO(shared_cpu_map);
 333 static DEVICE_ATTR_RO(shared_cpu_list);
 334 static DEVICE_ATTR_RO(physical_line_partition);
 335
 336 static struct attribute *cache_default_attrs[] = {
 337         &dev_attr_type.attr,
 338         &dev_attr_level.attr,
 339         &dev_attr_shared_cpu_map.attr,
 340         &dev_attr_shared_cpu_list.attr,
 341         &dev_attr_coherency_line_size.attr,
 342         &dev_attr_ways_of_associativity.attr,
 343         &dev_attr_number_of_sets.attr,
 344         &dev_attr_size.attr,
 345         &dev_attr_allocation_policy.attr,
 346         &dev_attr_write_policy.attr,
 347         &dev_attr_physical_line_partition.attr,
 348         NULL
 349 };
 350
 351 static umode_t
 352 cache_default_attrs_is_visible(struct kobject *kobj,
 353                                struct attribute *attr, int unused)
 354 {
 355         struct device *dev = kobj_to_dev(kobj);
 356         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 357         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 358         umode_t mode = attr->mode;
 359
 360         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 361                 return mode;
 362         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 363                 return mode;
 364         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 365                 return mode;
 366         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 367                 return mode;
 368         if ((attr == &dev_attr_coherency_line_size.attr) &&
 369             this_leaf->coherency_line_size)
 370                 return mode;
 371         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 372             this_leaf->size) /* allow 0 = full associativity */
 373                 return mode;
 374         if ((attr == &dev_attr_number_of_sets.attr) &&
 375             this_leaf->number_of_sets)
 376                 return mode;
 377         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 378                 return mode;
 379         if ((attr == &dev_attr_write_policy.attr) &&
 380             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 381                 return mode;
 382         if ((attr == &dev_attr_allocation_policy.attr) &&
 383             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 384                 return mode;
 385         if ((attr == &dev_attr_physical_line_partition.attr) &&
 386             this_leaf->physical_line_partition)
 387                 return mode;
 388
 389         return 0;
 390 }
 391
 392 static const struct attribute_group cache_default_group = {
 393         .attrs = cache_default_attrs,
 394         .is_visible = cache_default_attrs_is_visible,
 395 };
 396
 397 static const struct attribute_group *cache_default_groups[] = {
 398         &cache_default_group,
 399         NULL,
 400 };
 401
 402 static const struct attribute_group *cache_private_groups[] = {
 403         &cache_default_group,
 404         NULL, /* Place holder for private group */
 405         NULL,
 406 };
 407
 408 const struct attribute_group *
 409 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 410 {
 411         return NULL;
 412 }
 413
 414 static const struct attribute_group **
 415 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 416 {
 417         const struct attribute_group *priv_group =
 418                         cache_get_priv_group(this_leaf);
 419
 420         if (!priv_group)
 421                 return cache_default_groups;
 422
 423         if (!cache_private_groups[1])
 424                 cache_private_groups[1] = priv_group;
 425
 426         return cache_private_groups;
 427 }
 428
 429 /* Add/Remove cache interface for CPU device */
 430 static void cpu_cache_sysfs_exit(unsigned int cpu)
 431 {
 432         int i;
 433         struct device *ci_dev;
 434
 435         if (per_cpu_index_dev(cpu)) {
 436                 for (i = 0; i < cache_leaves(cpu); i++) {
 437                         ci_dev = per_cache_index_dev(cpu, i);
 438                         if (!ci_dev)
 439                                 continue;
 440                         device_unregister(ci_dev);
 441                 }
 442                 kfree(per_cpu_index_dev(cpu));
 443                 per_cpu_index_dev(cpu) = NULL;
 444         }
 445         device_unregister(per_cpu_cache_dev(cpu));
 446         per_cpu_cache_dev(cpu) = NULL;
 447 }
 448
 449 static int cpu_cache_sysfs_init(unsigned int cpu)
 450 {
 451         struct device *dev = get_cpu_device(cpu);
 452
 453         if (per_cpu_cacheinfo(cpu) == NULL)
 454                 return -ENOENT;
 455
 456         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 457         if (IS_ERR(per_cpu_cache_dev(cpu)))
 458                 return PTR_ERR(per_cpu_cache_dev(cpu));
 459
 460         /* Allocate all required memory */
 461         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 462                                          sizeof(struct device *), GFP_KERNEL);
 463         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 464                 goto err_out;
 465
 466         return 0;
 467
 468 err_out:
 469         cpu_cache_sysfs_exit(cpu);
 470         return -ENOMEM;
 471 }
 472
 473 static int cache_add_dev(unsigned int cpu)
 474 {
 475         unsigned int i;
 476         int rc;
 477         struct device *ci_dev, *parent;
 478         struct cacheinfo *this_leaf;
 479         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 480         const struct attribute_group **cache_groups;
 481
 482         rc = cpu_cache_sysfs_init(cpu);
 483         if (unlikely(rc < 0))
 484                 return rc;
 485
 486         parent = per_cpu_cache_dev(cpu);
 487         for (i = 0; i < cache_leaves(cpu); i++) {
 488                 this_leaf = this_cpu_ci->info_list + i;
 489                 if (this_leaf->disable_sysfs)
 490                         continue;
 491                 cache_groups = cache_get_attribute_groups(this_leaf);
 492                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 493                                            "index%1u", i);
 494                 if (IS_ERR(ci_dev)) {
 495                         rc = PTR_ERR(ci_dev);
 496                         goto err;
 497                 }
 498                 per_cache_index_dev(cpu, i) = ci_dev;
 499         }
 500         cpumask_set_cpu(cpu, &cache_dev_map);
 501
 502         return 0;
 503 err:
 504         cpu_cache_sysfs_exit(cpu);
 505         return rc;
 506 }
 507
 508 static void cache_remove_dev(unsigned int cpu)
 509 {
 510         if (!cpumask_test_cpu(cpu, &cache_dev_map))
 511                 return;
 512         cpumask_clear_cpu(cpu, &cache_dev_map);
 513
 514         cpu_cache_sysfs_exit(cpu);
 515 }
 516
 517 static int cacheinfo_cpu_callback(struct notifier_block *nfb,
 518                                   unsigned long action, void *hcpu)
 519 {
 520         unsigned int cpu = (unsigned long)hcpu;
 521         int rc = 0;
 522
 523         switch (action & ~CPU_TASKS_FROZEN) {
 524         case CPU_ONLINE:
 525                 rc = detect_cache_attributes(cpu);
 526                 if (!rc)
 527                         rc = cache_add_dev(cpu);
 528                 break;
 529         case CPU_DEAD:
 530                 cache_remove_dev(cpu);
 531                 free_cache_attributes(cpu);
 532                 break;
 533         }
 534         return notifier_from_errno(rc);
 535 }
 536
 537 static int __init cacheinfo_sysfs_init(void)
 538 {
 539         int cpu, rc = 0;
 540
 541         cpu_notifier_register_begin();
 542
 543         for_each_online_cpu(cpu) {
 544                 rc = detect_cache_attributes(cpu);
 545                 if (rc)
 546                         goto out;
 547                 rc = cache_add_dev(cpu);
 548                 if (rc) {
 549                         free_cache_attributes(cpu);
 550                         pr_err("error populating cacheinfo..cpu%d\n", cpu);
 551                         goto out;
 552                 }
 553         }
 554         __hotcpu_notifier(cacheinfo_cpu_callback, 0);
 555
 556 out:
 557         cpu_notifier_register_done();
 558         return rc;
 559 }
 560
 561 device_initcall(cacheinfo_sysfs_init);