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 <sudeep.holla@arm.com>
   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.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 /* Set if no cache information is found in DT/ACPI. */
  32 static bool use_arch_info;
  33
  34 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
  35 {
  36         return ci_cacheinfo(cpu);
  37 }
  38
  39 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
  40                                            struct cacheinfo *sib_leaf)
  41 {
  42         /*
  43          * For non DT/ACPI systems, assume unique level 1 caches,
  44          * system-wide shared caches for all other levels.
  45          */
  46         if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)) ||
  47             use_arch_info)
  48                 return (this_leaf->level != 1) && (sib_leaf->level != 1);
  49
  50         if ((sib_leaf->attributes & CACHE_ID) &&
  51             (this_leaf->attributes & CACHE_ID))
  52                 return sib_leaf->id == this_leaf->id;
  53
  54         return sib_leaf->fw_token == this_leaf->fw_token;
  55 }
  56
  57 bool last_level_cache_is_valid(unsigned int cpu)
  58 {
  59         struct cacheinfo *llc;
  60
  61         if (!cache_leaves(cpu))
  62                 return false;
  63
  64         llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
  65
  66         return (llc->attributes & CACHE_ID) || !!llc->fw_token;
  67
  68 }
  69
  70 bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
  71 {
  72         struct cacheinfo *llc_x, *llc_y;
  73
  74         if (!last_level_cache_is_valid(cpu_x) ||
  75             !last_level_cache_is_valid(cpu_y))
  76                 return false;
  77
  78         llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1);
  79         llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1);
  80
  81         return cache_leaves_are_shared(llc_x, llc_y);
  82 }
  83
  84 #ifdef CONFIG_OF
  85
  86 static bool of_check_cache_nodes(struct device_node *np);
  87
  88 /* OF properties to query for a given cache type */
  89 struct cache_type_info {
  90         const char *size_prop;
  91         const char *line_size_props[2];
  92         const char *nr_sets_prop;
  93 };
  94
  95 static const struct cache_type_info cache_type_info[] = {
  96         {
  97                 .size_prop       = "cache-size",
  98                 .line_size_props = { "cache-line-size",
  99                                      "cache-block-size", },
 100                 .nr_sets_prop    = "cache-sets",
 101         }, {
 102                 .size_prop       = "i-cache-size",
 103                 .line_size_props = { "i-cache-line-size",
 104                                      "i-cache-block-size", },
 105                 .nr_sets_prop    = "i-cache-sets",
 106         }, {
 107                 .size_prop       = "d-cache-size",
 108                 .line_size_props = { "d-cache-line-size",
 109                                      "d-cache-block-size", },
 110                 .nr_sets_prop    = "d-cache-sets",
 111         },
 112 };
 113
 114 static inline int get_cacheinfo_idx(enum cache_type type)
 115 {
 116         if (type == CACHE_TYPE_UNIFIED)
 117                 return 0;
 118         return type;
 119 }
 120
 121 static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
 122 {
 123         const char *propname;
 124         int ct_idx;
 125
 126         ct_idx = get_cacheinfo_idx(this_leaf->type);
 127         propname = cache_type_info[ct_idx].size_prop;
 128
 129         of_property_read_u32(np, propname, &this_leaf->size);
 130 }
 131
 132 /* not cache_line_size() because that's a macro in include/linux/cache.h */
 133 static void cache_get_line_size(struct cacheinfo *this_leaf,
 134                                 struct device_node *np)
 135 {
 136         int i, lim, ct_idx;
 137
 138         ct_idx = get_cacheinfo_idx(this_leaf->type);
 139         lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
 140
 141         for (i = 0; i < lim; i++) {
 142                 int ret;
 143                 u32 line_size;
 144                 const char *propname;
 145
 146                 propname = cache_type_info[ct_idx].line_size_props[i];
 147                 ret = of_property_read_u32(np, propname, &line_size);
 148                 if (!ret) {
 149                         this_leaf->coherency_line_size = line_size;
 150                         break;
 151                 }
 152         }
 153 }
 154
 155 static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
 156 {
 157         const char *propname;
 158         int ct_idx;
 159
 160         ct_idx = get_cacheinfo_idx(this_leaf->type);
 161         propname = cache_type_info[ct_idx].nr_sets_prop;
 162
 163         of_property_read_u32(np, propname, &this_leaf->number_of_sets);
 164 }
 165
 166 static void cache_associativity(struct cacheinfo *this_leaf)
 167 {
 168         unsigned int line_size = this_leaf->coherency_line_size;
 169         unsigned int nr_sets = this_leaf->number_of_sets;
 170         unsigned int size = this_leaf->size;
 171
 172         /*
 173          * If the cache is fully associative, there is no need to
 174          * check the other properties.
 175          */
 176         if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
 177                 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
 178 }
 179
 180 static bool cache_node_is_unified(struct cacheinfo *this_leaf,
 181                                   struct device_node *np)
 182 {
 183         return of_property_read_bool(np, "cache-unified");
 184 }
 185
 186 static void cache_of_set_props(struct cacheinfo *this_leaf,
 187                                struct device_node *np)
 188 {
 189         /*
 190          * init_cache_level must setup the cache level correctly
 191          * overriding the architecturally specified levels, so
 192          * if type is NONE at this stage, it should be unified
 193          */
 194         if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 195             cache_node_is_unified(this_leaf, np))
 196                 this_leaf->type = CACHE_TYPE_UNIFIED;
 197         cache_size(this_leaf, np);
 198         cache_get_line_size(this_leaf, np);
 199         cache_nr_sets(this_leaf, np);
 200         cache_associativity(this_leaf);
 201 }
 202
 203 static int cache_setup_of_node(unsigned int cpu)
 204 {
 205         struct device_node *np, *prev;
 206         struct cacheinfo *this_leaf;
 207         unsigned int index = 0;
 208
 209         np = of_cpu_device_node_get(cpu);
 210         if (!np) {
 211                 pr_err("Failed to find cpu%d device node\n", cpu);
 212                 return -ENOENT;
 213         }
 214
 215         if (!of_check_cache_nodes(np)) {
 216                 of_node_put(np);
 217                 return -ENOENT;
 218         }
 219
 220         prev = np;
 221
 222         while (index < cache_leaves(cpu)) {
 223                 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
 224                 if (this_leaf->level != 1) {
 225                         np = of_find_next_cache_node(np);
 226                         of_node_put(prev);
 227                         prev = np;
 228                         if (!np)
 229                                 break;
 230                 }
 231                 cache_of_set_props(this_leaf, np);
 232                 this_leaf->fw_token = np;
 233                 index++;
 234         }
 235
 236         of_node_put(np);
 237
 238         if (index != cache_leaves(cpu)) /* not all OF nodes populated */
 239                 return -ENOENT;
 240
 241         return 0;
 242 }
 243
 244 static bool of_check_cache_nodes(struct device_node *np)
 245 {
 246         struct device_node *next;
 247
 248         if (of_property_present(np, "cache-size")   ||
 249             of_property_present(np, "i-cache-size") ||
 250             of_property_present(np, "d-cache-size") ||
 251             of_property_present(np, "cache-unified"))
 252                 return true;
 253
 254         next = of_find_next_cache_node(np);
 255         if (next) {
 256                 of_node_put(next);
 257                 return true;
 258         }
 259
 260         return false;
 261 }
 262
 263 static int of_count_cache_leaves(struct device_node *np)
 264 {
 265         unsigned int leaves = 0;
 266
 267         if (of_property_read_bool(np, "cache-size"))
 268                 ++leaves;
 269         if (of_property_read_bool(np, "i-cache-size"))
 270                 ++leaves;
 271         if (of_property_read_bool(np, "d-cache-size"))
 272                 ++leaves;
 273
 274         if (!leaves) {
 275                 /* The '[i-|d-|]cache-size' property is required, but
 276                  * if absent, fallback on the 'cache-unified' property.
 277                  */
 278                 if (of_property_read_bool(np, "cache-unified"))
 279                         return 1;
 280                 else
 281                         return 2;
 282         }
 283
 284         return leaves;
 285 }
 286
 287 int init_of_cache_level(unsigned int cpu)
 288 {
 289         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 290         struct device_node *np = of_cpu_device_node_get(cpu);
 291         struct device_node *prev = NULL;
 292         unsigned int levels = 0, leaves, level;
 293
 294         if (!of_check_cache_nodes(np)) {
 295                 of_node_put(np);
 296                 return -ENOENT;
 297         }
 298
 299         leaves = of_count_cache_leaves(np);
 300         if (leaves > 0)
 301                 levels = 1;
 302
 303         prev = np;
 304         while ((np = of_find_next_cache_node(np))) {
 305                 of_node_put(prev);
 306                 prev = np;
 307                 if (!of_device_is_compatible(np, "cache"))
 308                         goto err_out;
 309                 if (of_property_read_u32(np, "cache-level", &level))
 310                         goto err_out;
 311                 if (level <= levels)
 312                         goto err_out;
 313
 314                 leaves += of_count_cache_leaves(np);
 315                 levels = level;
 316         }
 317
 318         of_node_put(np);
 319         this_cpu_ci->num_levels = levels;
 320         this_cpu_ci->num_leaves = leaves;
 321
 322         return 0;
 323
 324 err_out:
 325         of_node_put(np);
 326         return -EINVAL;
 327 }
 328
 329 #else
 330 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
 331 int init_of_cache_level(unsigned int cpu) { return 0; }
 332 #endif
 333
 334 int __weak cache_setup_acpi(unsigned int cpu)
 335 {
 336         return -ENOTSUPP;
 337 }
 338
 339 unsigned int coherency_max_size;
 340
 341 static int cache_setup_properties(unsigned int cpu)
 342 {
 343         int ret = 0;
 344
 345         if (of_have_populated_dt())
 346                 ret = cache_setup_of_node(cpu);
 347         else if (!acpi_disabled)
 348                 ret = cache_setup_acpi(cpu);
 349
 350         // Assume there is no cache information available in DT/ACPI from now.
 351         if (ret && use_arch_cache_info())
 352                 use_arch_info = true;
 353
 354         return ret;
 355 }
 356
 357 static int cache_shared_cpu_map_setup(unsigned int cpu)
 358 {
 359         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 360         struct cacheinfo *this_leaf, *sib_leaf;
 361         unsigned int index, sib_index;
 362         int ret = 0;
 363
 364         if (this_cpu_ci->cpu_map_populated)
 365                 return 0;
 366
 367         /*
 368          * skip setting up cache properties if LLC is valid, just need
 369          * to update the shared cpu_map if the cache attributes were
 370          * populated early before all the cpus are brought online
 371          */
 372         if (!last_level_cache_is_valid(cpu) && !use_arch_info) {
 373                 ret = cache_setup_properties(cpu);
 374                 if (ret)
 375                         return ret;
 376         }
 377
 378         for (index = 0; index < cache_leaves(cpu); index++) {
 379                 unsigned int i;
 380
 381                 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
 382
 383                 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
 384                 for_each_online_cpu(i) {
 385                         struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
 386
 387                         if (i == cpu || !sib_cpu_ci->info_list)
 388                                 continue;/* skip if itself or no cacheinfo */
 389                         for (sib_index = 0; sib_index < cache_leaves(i); sib_index++) {
 390                                 sib_leaf = per_cpu_cacheinfo_idx(i, sib_index);
 391                                 if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 392                                         cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
 393                                         cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
 394                                         break;
 395                                 }
 396                         }
 397                 }
 398                 /* record the maximum cache line size */
 399                 if (this_leaf->coherency_line_size > coherency_max_size)
 400                         coherency_max_size = this_leaf->coherency_line_size;
 401         }
 402
 403         return 0;
 404 }
 405
 406 static void cache_shared_cpu_map_remove(unsigned int cpu)
 407 {
 408         struct cacheinfo *this_leaf, *sib_leaf;
 409         unsigned int sibling, index, sib_index;
 410
 411         for (index = 0; index < cache_leaves(cpu); index++) {
 412                 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
 413                 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
 414                         struct cpu_cacheinfo *sib_cpu_ci =
 415                                                 get_cpu_cacheinfo(sibling);
 416
 417                         if (sibling == cpu || !sib_cpu_ci->info_list)
 418                                 continue;/* skip if itself or no cacheinfo */
 419
 420                         for (sib_index = 0; sib_index < cache_leaves(sibling); sib_index++) {
 421                                 sib_leaf = per_cpu_cacheinfo_idx(sibling, sib_index);
 422                                 if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
 423                                         cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
 424                                         cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
 425                                         break;
 426                                 }
 427                         }
 428                 }
 429         }
 430 }
 431
 432 static void free_cache_attributes(unsigned int cpu)
 433 {
 434         if (!per_cpu_cacheinfo(cpu))
 435                 return;
 436
 437         cache_shared_cpu_map_remove(cpu);
 438 }
 439
 440 int __weak early_cache_level(unsigned int cpu)
 441 {
 442         return -ENOENT;
 443 }
 444
 445 int __weak init_cache_level(unsigned int cpu)
 446 {
 447         return -ENOENT;
 448 }
 449
 450 int __weak populate_cache_leaves(unsigned int cpu)
 451 {
 452         return -ENOENT;
 453 }
 454
 455 static inline
 456 int allocate_cache_info(int cpu)
 457 {
 458         per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
 459                                          sizeof(struct cacheinfo), GFP_ATOMIC);
 460         if (!per_cpu_cacheinfo(cpu)) {
 461                 cache_leaves(cpu) = 0;
 462                 return -ENOMEM;
 463         }
 464
 465         return 0;
 466 }
 467
 468 int fetch_cache_info(unsigned int cpu)
 469 {
 470         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 471         unsigned int levels = 0, split_levels = 0;
 472         int ret;
 473
 474         if (acpi_disabled) {
 475                 ret = init_of_cache_level(cpu);
 476         } else {
 477                 ret = acpi_get_cache_info(cpu, &levels, &split_levels);
 478                 if (!ret) {
 479                         this_cpu_ci->num_levels = levels;
 480                         /*
 481                          * This assumes that:
 482                          * - there cannot be any split caches (data/instruction)
 483                          *   above a unified cache
 484                          * - data/instruction caches come by pair
 485                          */
 486                         this_cpu_ci->num_leaves = levels + split_levels;
 487                 }
 488         }
 489
 490         if (ret || !cache_leaves(cpu)) {
 491                 ret = early_cache_level(cpu);
 492                 if (ret)
 493                         return ret;
 494
 495                 if (!cache_leaves(cpu))
 496                         return -ENOENT;
 497
 498                 this_cpu_ci->early_ci_levels = true;
 499         }
 500
 501         return allocate_cache_info(cpu);
 502 }
 503
 504 static inline int init_level_allocate_ci(unsigned int cpu)
 505 {
 506         unsigned int early_leaves = cache_leaves(cpu);
 507
 508         /* Since early initialization/allocation of the cacheinfo is allowed
 509          * via fetch_cache_info() and this also gets called as CPU hotplug
 510          * callbacks via cacheinfo_cpu_online, the init/alloc can be skipped
 511          * as it will happen only once (the cacheinfo memory is never freed).
 512          * Just populate the cacheinfo. However, if the cacheinfo has been
 513          * allocated early through the arch-specific early_cache_level() call,
 514          * there is a chance the info is wrong (this can happen on arm64). In
 515          * that case, call init_cache_level() anyway to give the arch-specific
 516          * code a chance to make things right.
 517          */
 518         if (per_cpu_cacheinfo(cpu) && !ci_cacheinfo(cpu)->early_ci_levels)
 519                 return 0;
 520
 521         if (init_cache_level(cpu) || !cache_leaves(cpu))
 522                 return -ENOENT;
 523
 524         /*
 525          * Now that we have properly initialized the cache level info, make
 526          * sure we don't try to do that again the next time we are called
 527          * (e.g. as CPU hotplug callbacks).
 528          */
 529         ci_cacheinfo(cpu)->early_ci_levels = false;
 530
 531         if (cache_leaves(cpu) <= early_leaves)
 532                 return 0;
 533
 534         kfree(per_cpu_cacheinfo(cpu));
 535         return allocate_cache_info(cpu);
 536 }
 537
 538 int detect_cache_attributes(unsigned int cpu)
 539 {
 540         int ret;
 541
 542         ret = init_level_allocate_ci(cpu);
 543         if (ret)
 544                 return ret;
 545
 546         /*
 547          * If LLC is valid the cache leaves were already populated so just go to
 548          * update the cpu map.
 549          */
 550         if (!last_level_cache_is_valid(cpu)) {
 551                 /*
 552                  * populate_cache_leaves() may completely setup the cache leaves and
 553                  * shared_cpu_map or it may leave it partially setup.
 554                  */
 555                 ret = populate_cache_leaves(cpu);
 556                 if (ret)
 557                         goto free_ci;
 558         }
 559
 560         /*
 561          * For systems using DT for cache hierarchy, fw_token
 562          * and shared_cpu_map will be set up here only if they are
 563          * not populated already
 564          */
 565         ret = cache_shared_cpu_map_setup(cpu);
 566         if (ret) {
 567                 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
 568                 goto free_ci;
 569         }
 570
 571         return 0;
 572
 573 free_ci:
 574         free_cache_attributes(cpu);
 575         return ret;
 576 }
 577
 578 /* pointer to cpuX/cache device */
 579 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
 580 #define per_cpu_cache_dev(cpu)  (per_cpu(ci_cache_dev, cpu))
 581
 582 static cpumask_t cache_dev_map;
 583
 584 /* pointer to array of devices for cpuX/cache/indexY */
 585 static DEFINE_PER_CPU(struct device **, ci_index_dev);
 586 #define per_cpu_index_dev(cpu)  (per_cpu(ci_index_dev, cpu))
 587 #define per_cache_index_dev(cpu, idx)   ((per_cpu_index_dev(cpu))[idx])
 588
 589 #define show_one(file_name, object)                             \
 590 static ssize_t file_name##_show(struct device *dev,             \
 591                 struct device_attribute *attr, char *buf)       \
 592 {                                                               \
 593         struct cacheinfo *this_leaf = dev_get_drvdata(dev);     \
 594         return sysfs_emit(buf, "%u\n", this_leaf->object);      \
 595 }
 596
 597 show_one(id, id);
 598 show_one(level, level);
 599 show_one(coherency_line_size, coherency_line_size);
 600 show_one(number_of_sets, number_of_sets);
 601 show_one(physical_line_partition, physical_line_partition);
 602 show_one(ways_of_associativity, ways_of_associativity);
 603
 604 static ssize_t size_show(struct device *dev,
 605                          struct device_attribute *attr, char *buf)
 606 {
 607         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 608
 609         return sysfs_emit(buf, "%uK\n", this_leaf->size >> 10);
 610 }
 611
 612 static ssize_t shared_cpu_map_show(struct device *dev,
 613                                    struct device_attribute *attr, char *buf)
 614 {
 615         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 616         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 617
 618         return sysfs_emit(buf, "%*pb\n", nr_cpu_ids, mask);
 619 }
 620
 621 static ssize_t shared_cpu_list_show(struct device *dev,
 622                                     struct device_attribute *attr, char *buf)
 623 {
 624         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 625         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 626
 627         return sysfs_emit(buf, "%*pbl\n", nr_cpu_ids, mask);
 628 }
 629
 630 static ssize_t type_show(struct device *dev,
 631                          struct device_attribute *attr, char *buf)
 632 {
 633         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 634         const char *output;
 635
 636         switch (this_leaf->type) {
 637         case CACHE_TYPE_DATA:
 638                 output = "Data";
 639                 break;
 640         case CACHE_TYPE_INST:
 641                 output = "Instruction";
 642                 break;
 643         case CACHE_TYPE_UNIFIED:
 644                 output = "Unified";
 645                 break;
 646         default:
 647                 return -EINVAL;
 648         }
 649
 650         return sysfs_emit(buf, "%s\n", output);
 651 }
 652
 653 static ssize_t allocation_policy_show(struct device *dev,
 654                                       struct device_attribute *attr, char *buf)
 655 {
 656         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 657         unsigned int ci_attr = this_leaf->attributes;
 658         const char *output;
 659
 660         if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
 661                 output = "ReadWriteAllocate";
 662         else if (ci_attr & CACHE_READ_ALLOCATE)
 663                 output = "ReadAllocate";
 664         else if (ci_attr & CACHE_WRITE_ALLOCATE)
 665                 output = "WriteAllocate";
 666         else
 667                 return 0;
 668
 669         return sysfs_emit(buf, "%s\n", output);
 670 }
 671
 672 static ssize_t write_policy_show(struct device *dev,
 673                                  struct device_attribute *attr, char *buf)
 674 {
 675         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 676         unsigned int ci_attr = this_leaf->attributes;
 677         int n = 0;
 678
 679         if (ci_attr & CACHE_WRITE_THROUGH)
 680                 n = sysfs_emit(buf, "WriteThrough\n");
 681         else if (ci_attr & CACHE_WRITE_BACK)
 682                 n = sysfs_emit(buf, "WriteBack\n");
 683         return n;
 684 }
 685
 686 static DEVICE_ATTR_RO(id);
 687 static DEVICE_ATTR_RO(level);
 688 static DEVICE_ATTR_RO(type);
 689 static DEVICE_ATTR_RO(coherency_line_size);
 690 static DEVICE_ATTR_RO(ways_of_associativity);
 691 static DEVICE_ATTR_RO(number_of_sets);
 692 static DEVICE_ATTR_RO(size);
 693 static DEVICE_ATTR_RO(allocation_policy);
 694 static DEVICE_ATTR_RO(write_policy);
 695 static DEVICE_ATTR_RO(shared_cpu_map);
 696 static DEVICE_ATTR_RO(shared_cpu_list);
 697 static DEVICE_ATTR_RO(physical_line_partition);
 698
 699 static struct attribute *cache_default_attrs[] = {
 700         &dev_attr_id.attr,
 701         &dev_attr_type.attr,
 702         &dev_attr_level.attr,
 703         &dev_attr_shared_cpu_map.attr,
 704         &dev_attr_shared_cpu_list.attr,
 705         &dev_attr_coherency_line_size.attr,
 706         &dev_attr_ways_of_associativity.attr,
 707         &dev_attr_number_of_sets.attr,
 708         &dev_attr_size.attr,
 709         &dev_attr_allocation_policy.attr,
 710         &dev_attr_write_policy.attr,
 711         &dev_attr_physical_line_partition.attr,
 712         NULL
 713 };
 714
 715 static umode_t
 716 cache_default_attrs_is_visible(struct kobject *kobj,
 717                                struct attribute *attr, int unused)
 718 {
 719         struct device *dev = kobj_to_dev(kobj);
 720         struct cacheinfo *this_leaf = dev_get_drvdata(dev);
 721         const struct cpumask *mask = &this_leaf->shared_cpu_map;
 722         umode_t mode = attr->mode;
 723
 724         if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
 725                 return mode;
 726         if ((attr == &dev_attr_type.attr) && this_leaf->type)
 727                 return mode;
 728         if ((attr == &dev_attr_level.attr) && this_leaf->level)
 729                 return mode;
 730         if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
 731                 return mode;
 732         if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
 733                 return mode;
 734         if ((attr == &dev_attr_coherency_line_size.attr) &&
 735             this_leaf->coherency_line_size)
 736                 return mode;
 737         if ((attr == &dev_attr_ways_of_associativity.attr) &&
 738             this_leaf->size) /* allow 0 = full associativity */
 739                 return mode;
 740         if ((attr == &dev_attr_number_of_sets.attr) &&
 741             this_leaf->number_of_sets)
 742                 return mode;
 743         if ((attr == &dev_attr_size.attr) && this_leaf->size)
 744                 return mode;
 745         if ((attr == &dev_attr_write_policy.attr) &&
 746             (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
 747                 return mode;
 748         if ((attr == &dev_attr_allocation_policy.attr) &&
 749             (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
 750                 return mode;
 751         if ((attr == &dev_attr_physical_line_partition.attr) &&
 752             this_leaf->physical_line_partition)
 753                 return mode;
 754
 755         return 0;
 756 }
 757
 758 static const struct attribute_group cache_default_group = {
 759         .attrs = cache_default_attrs,
 760         .is_visible = cache_default_attrs_is_visible,
 761 };
 762
 763 static const struct attribute_group *cache_default_groups[] = {
 764         &cache_default_group,
 765         NULL,
 766 };
 767
 768 static const struct attribute_group *cache_private_groups[] = {
 769         &cache_default_group,
 770         NULL, /* Place holder for private group */
 771         NULL,
 772 };
 773
 774 const struct attribute_group *
 775 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
 776 {
 777         return NULL;
 778 }
 779
 780 static const struct attribute_group **
 781 cache_get_attribute_groups(struct cacheinfo *this_leaf)
 782 {
 783         const struct attribute_group *priv_group =
 784                         cache_get_priv_group(this_leaf);
 785
 786         if (!priv_group)
 787                 return cache_default_groups;
 788
 789         if (!cache_private_groups[1])
 790                 cache_private_groups[1] = priv_group;
 791
 792         return cache_private_groups;
 793 }
 794
 795 /* Add/Remove cache interface for CPU device */
 796 static void cpu_cache_sysfs_exit(unsigned int cpu)
 797 {
 798         int i;
 799         struct device *ci_dev;
 800
 801         if (per_cpu_index_dev(cpu)) {
 802                 for (i = 0; i < cache_leaves(cpu); i++) {
 803                         ci_dev = per_cache_index_dev(cpu, i);
 804                         if (!ci_dev)
 805                                 continue;
 806                         device_unregister(ci_dev);
 807                 }
 808                 kfree(per_cpu_index_dev(cpu));
 809                 per_cpu_index_dev(cpu) = NULL;
 810         }
 811         device_unregister(per_cpu_cache_dev(cpu));
 812         per_cpu_cache_dev(cpu) = NULL;
 813 }
 814
 815 static int cpu_cache_sysfs_init(unsigned int cpu)
 816 {
 817         struct device *dev = get_cpu_device(cpu);
 818
 819         if (per_cpu_cacheinfo(cpu) == NULL)
 820                 return -ENOENT;
 821
 822         per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
 823         if (IS_ERR(per_cpu_cache_dev(cpu)))
 824                 return PTR_ERR(per_cpu_cache_dev(cpu));
 825
 826         /* Allocate all required memory */
 827         per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
 828                                          sizeof(struct device *), GFP_KERNEL);
 829         if (unlikely(per_cpu_index_dev(cpu) == NULL))
 830                 goto err_out;
 831
 832         return 0;
 833
 834 err_out:
 835         cpu_cache_sysfs_exit(cpu);
 836         return -ENOMEM;
 837 }
 838
 839 static int cache_add_dev(unsigned int cpu)
 840 {
 841         unsigned int i;
 842         int rc;
 843         struct device *ci_dev, *parent;
 844         struct cacheinfo *this_leaf;
 845         const struct attribute_group **cache_groups;
 846
 847         rc = cpu_cache_sysfs_init(cpu);
 848         if (unlikely(rc < 0))
 849                 return rc;
 850
 851         parent = per_cpu_cache_dev(cpu);
 852         for (i = 0; i < cache_leaves(cpu); i++) {
 853                 this_leaf = per_cpu_cacheinfo_idx(cpu, i);
 854                 if (this_leaf->disable_sysfs)
 855                         continue;
 856                 if (this_leaf->type == CACHE_TYPE_NOCACHE)
 857                         break;
 858                 cache_groups = cache_get_attribute_groups(this_leaf);
 859                 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
 860                                            "index%1u", i);
 861                 if (IS_ERR(ci_dev)) {
 862                         rc = PTR_ERR(ci_dev);
 863                         goto err;
 864                 }
 865                 per_cache_index_dev(cpu, i) = ci_dev;
 866         }
 867         cpumask_set_cpu(cpu, &cache_dev_map);
 868
 869         return 0;
 870 err:
 871         cpu_cache_sysfs_exit(cpu);
 872         return rc;
 873 }
 874
 875 static int cacheinfo_cpu_online(unsigned int cpu)
 876 {
 877         int rc = detect_cache_attributes(cpu);
 878
 879         if (rc)
 880                 return rc;
 881         rc = cache_add_dev(cpu);
 882         if (rc)
 883                 free_cache_attributes(cpu);
 884         return rc;
 885 }
 886
 887 static int cacheinfo_cpu_pre_down(unsigned int cpu)
 888 {
 889         if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
 890                 cpu_cache_sysfs_exit(cpu);
 891
 892         free_cache_attributes(cpu);
 893         return 0;
 894 }
 895
 896 static int __init cacheinfo_sysfs_init(void)
 897 {
 898         return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
 899                                  "base/cacheinfo:online",
 900                                  cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
 901 }
 902 device_initcall(cacheinfo_sysfs_init);