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