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