root/drivers/acpi/pptt.c

DEFINITIONS

1. fetch_pptt_subtable
2. fetch_pptt_node
3. fetch_pptt_cache
4. acpi_get_pptt_resource
5. acpi_pptt_match_type
6. acpi_pptt_walk_cache
7. acpi_find_cache_level
8. acpi_count_levels
9. acpi_pptt_leaf_node
10. acpi_find_processor_node
11. acpi_find_cache_levels
12. acpi_cache_type
13. acpi_find_cache_node
14. update_cache_properties
15. cache_setup_acpi_cpu
16. flag_identical
17. acpi_find_processor_tag
18. acpi_pptt_warn_missing
19. topology_get_acpi_cpu_tag
20. find_acpi_cpu_topology_tag
21. check_acpi_cpu_flag
22. acpi_find_last_cache_level
23. cache_setup_acpi
24. acpi_pptt_cpu_is_thread
25. find_acpi_cpu_topology
26. find_acpi_cpu_cache_topology
27. find_acpi_cpu_topology_package
28. find_acpi_cpu_topology_hetero_id

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * pptt.c - parsing of Processor Properties Topology Table (PPTT)
   4  *
   5  * Copyright (C) 2018, ARM
   6  *
   7  * This file implements parsing of the Processor Properties Topology Table
   8  * which is optionally used to describe the processor and cache topology.
   9  * Due to the relative pointers used throughout the table, this doesn't
  10  * leverage the existing subtable parsing in the kernel.
  11  *
  12  * The PPTT structure is an inverted tree, with each node potentially
  13  * holding one or two inverted tree data structures describing
  14  * the caches available at that level. Each cache structure optionally
  15  * contains properties describing the cache at a given level which can be
  16  * used to override hardware probed values.
  17  */
  18 #define pr_fmt(fmt) "ACPI PPTT: " fmt
  19 
  20 #include <linux/acpi.h>
  21 #include <linux/cacheinfo.h>
  22 #include <acpi/processor.h>
  23 
  24 static struct acpi_subtable_header *fetch_pptt_subtable(struct acpi_table_header *table_hdr,
  25                                                         u32 pptt_ref)
  26 {
  27         struct acpi_subtable_header *entry;
  28 
  29         /* there isn't a subtable at reference 0 */
  30         if (pptt_ref < sizeof(struct acpi_subtable_header))
  31                 return NULL;
  32 
  33         if (pptt_ref + sizeof(struct acpi_subtable_header) > table_hdr->length)
  34                 return NULL;
  35 
  36         entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr, pptt_ref);
  37 
  38         if (entry->length == 0)
  39                 return NULL;
  40 
  41         if (pptt_ref + entry->length > table_hdr->length)
  42                 return NULL;
  43 
  44         return entry;
  45 }
  46 
  47 static struct acpi_pptt_processor *fetch_pptt_node(struct acpi_table_header *table_hdr,
  48                                                    u32 pptt_ref)
  49 {
  50         return (struct acpi_pptt_processor *)fetch_pptt_subtable(table_hdr, pptt_ref);
  51 }
  52 
  53 static struct acpi_pptt_cache *fetch_pptt_cache(struct acpi_table_header *table_hdr,
  54                                                 u32 pptt_ref)
  55 {
  56         return (struct acpi_pptt_cache *)fetch_pptt_subtable(table_hdr, pptt_ref);
  57 }
  58 
  59 static struct acpi_subtable_header *acpi_get_pptt_resource(struct acpi_table_header *table_hdr,
  60                                                            struct acpi_pptt_processor *node,
  61                                                            int resource)
  62 {
  63         u32 *ref;
  64 
  65         if (resource >= node->number_of_priv_resources)
  66                 return NULL;
  67 
  68         ref = ACPI_ADD_PTR(u32, node, sizeof(struct acpi_pptt_processor));
  69         ref += resource;
  70 
  71         return fetch_pptt_subtable(table_hdr, *ref);
  72 }
  73 
  74 static inline bool acpi_pptt_match_type(int table_type, int type)
  75 {
  76         return ((table_type & ACPI_PPTT_MASK_CACHE_TYPE) == type ||
  77                 table_type & ACPI_PPTT_CACHE_TYPE_UNIFIED & type);
  78 }
  79 
  80 /**
  81  * acpi_pptt_walk_cache() - Attempt to find the requested acpi_pptt_cache
  82  * @table_hdr: Pointer to the head of the PPTT table
  83  * @local_level: passed res reflects this cache level
  84  * @res: cache resource in the PPTT we want to walk
  85  * @found: returns a pointer to the requested level if found
  86  * @level: the requested cache level
  87  * @type: the requested cache type
  88  *
  89  * Attempt to find a given cache level, while counting the max number
  90  * of cache levels for the cache node.
  91  *
  92  * Given a pptt resource, verify that it is a cache node, then walk
  93  * down each level of caches, counting how many levels are found
  94  * as well as checking the cache type (icache, dcache, unified). If a
  95  * level & type match, then we set found, and continue the search.
  96  * Once the entire cache branch has been walked return its max
  97  * depth.
  98  *
  99  * Return: The cache structure and the level we terminated with.
 100  */
 101 static int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
 102                                 int local_level,
 103                                 struct acpi_subtable_header *res,
 104                                 struct acpi_pptt_cache **found,
 105                                 int level, int type)
 106 {
 107         struct acpi_pptt_cache *cache;
 108 
 109         if (res->type != ACPI_PPTT_TYPE_CACHE)
 110                 return 0;
 111 
 112         cache = (struct acpi_pptt_cache *) res;
 113         while (cache) {
 114                 local_level++;
 115 
 116                 if (local_level == level &&
 117                     cache->flags & ACPI_PPTT_CACHE_TYPE_VALID &&
 118                     acpi_pptt_match_type(cache->attributes, type)) {
 119                         if (*found != NULL && cache != *found)
 120                                 pr_warn("Found duplicate cache level/type unable to determine uniqueness\n");
 121 
 122                         pr_debug("Found cache @ level %d\n", level);
 123                         *found = cache;
 124                         /*
 125                          * continue looking at this node's resource list
 126                          * to verify that we don't find a duplicate
 127                          * cache node.
 128                          */
 129                 }
 130                 cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache);
 131         }
 132         return local_level;
 133 }
 134 
 135 static struct acpi_pptt_cache *acpi_find_cache_level(struct acpi_table_header *table_hdr,
 136                                                      struct acpi_pptt_processor *cpu_node,
 137                                                      int *starting_level, int level,
 138                                                      int type)
 139 {
 140         struct acpi_subtable_header *res;
 141         int number_of_levels = *starting_level;
 142         int resource = 0;
 143         struct acpi_pptt_cache *ret = NULL;
 144         int local_level;
 145 
 146         /* walk down from processor node */
 147         while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
 148                 resource++;
 149 
 150                 local_level = acpi_pptt_walk_cache(table_hdr, *starting_level,
 151                                                    res, &ret, level, type);
 152                 /*
 153                  * we are looking for the max depth. Since its potentially
 154                  * possible for a given node to have resources with differing
 155                  * depths verify that the depth we have found is the largest.
 156                  */
 157                 if (number_of_levels < local_level)
 158                         number_of_levels = local_level;
 159         }
 160         if (number_of_levels > *starting_level)
 161                 *starting_level = number_of_levels;
 162 
 163         return ret;
 164 }
 165 
 166 /**
 167  * acpi_count_levels() - Given a PPTT table, and a CPU node, count the caches
 168  * @table_hdr: Pointer to the head of the PPTT table
 169  * @cpu_node: processor node we wish to count caches for
 170  *
 171  * Given a processor node containing a processing unit, walk into it and count
 172  * how many levels exist solely for it, and then walk up each level until we hit
 173  * the root node (ignore the package level because it may be possible to have
 174  * caches that exist across packages). Count the number of cache levels that
 175  * exist at each level on the way up.
 176  *
 177  * Return: Total number of levels found.
 178  */
 179 static int acpi_count_levels(struct acpi_table_header *table_hdr,
 180                              struct acpi_pptt_processor *cpu_node)
 181 {
 182         int total_levels = 0;
 183 
 184         do {
 185                 acpi_find_cache_level(table_hdr, cpu_node, &total_levels, 0, 0);
 186                 cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
 187         } while (cpu_node);
 188 
 189         return total_levels;
 190 }
 191 
 192 /**
 193  * acpi_pptt_leaf_node() - Given a processor node, determine if its a leaf
 194  * @table_hdr: Pointer to the head of the PPTT table
 195  * @node: passed node is checked to see if its a leaf
 196  *
 197  * Determine if the *node parameter is a leaf node by iterating the
 198  * PPTT table, looking for nodes which reference it.
 199  *
 200  * Return: 0 if we find a node referencing the passed node (or table error),
 201  * or 1 if we don't.
 202  */
 203 static int acpi_pptt_leaf_node(struct acpi_table_header *table_hdr,
 204                                struct acpi_pptt_processor *node)
 205 {
 206         struct acpi_subtable_header *entry;
 207         unsigned long table_end;
 208         u32 node_entry;
 209         struct acpi_pptt_processor *cpu_node;
 210         u32 proc_sz;
 211 
 212         if (table_hdr->revision > 1)
 213                 return (node->flags & ACPI_PPTT_ACPI_LEAF_NODE);
 214 
 215         table_end = (unsigned long)table_hdr + table_hdr->length;
 216         node_entry = ACPI_PTR_DIFF(node, table_hdr);
 217         entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
 218                              sizeof(struct acpi_table_pptt));
 219         proc_sz = sizeof(struct acpi_pptt_processor *);
 220 
 221         while ((unsigned long)entry + proc_sz < table_end) {
 222                 cpu_node = (struct acpi_pptt_processor *)entry;
 223                 if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
 224                     cpu_node->parent == node_entry)
 225                         return 0;
 226                 if (entry->length == 0)
 227                         return 0;
 228                 entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
 229                                      entry->length);
 230 
 231         }
 232         return 1;
 233 }
 234 
 235 /**
 236  * acpi_find_processor_node() - Given a PPTT table find the requested processor
 237  * @table_hdr:  Pointer to the head of the PPTT table
 238  * @acpi_cpu_id: CPU we are searching for
 239  *
 240  * Find the subtable entry describing the provided processor.
 241  * This is done by iterating the PPTT table looking for processor nodes
 242  * which have an acpi_processor_id that matches the acpi_cpu_id parameter
 243  * passed into the function. If we find a node that matches this criteria
 244  * we verify that its a leaf node in the topology rather than depending
 245  * on the valid flag, which doesn't need to be set for leaf nodes.
 246  *
 247  * Return: NULL, or the processors acpi_pptt_processor*
 248  */
 249 static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_header *table_hdr,
 250                                                             u32 acpi_cpu_id)
 251 {
 252         struct acpi_subtable_header *entry;
 253         unsigned long table_end;
 254         struct acpi_pptt_processor *cpu_node;
 255         u32 proc_sz;
 256 
 257         table_end = (unsigned long)table_hdr + table_hdr->length;
 258         entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
 259                              sizeof(struct acpi_table_pptt));
 260         proc_sz = sizeof(struct acpi_pptt_processor *);
 261 
 262         /* find the processor structure associated with this cpuid */
 263         while ((unsigned long)entry + proc_sz < table_end) {
 264                 cpu_node = (struct acpi_pptt_processor *)entry;
 265 
 266                 if (entry->length == 0) {
 267                         pr_warn("Invalid zero length subtable\n");
 268                         break;
 269                 }
 270                 if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
 271                     acpi_cpu_id == cpu_node->acpi_processor_id &&
 272                      acpi_pptt_leaf_node(table_hdr, cpu_node)) {
 273                         return (struct acpi_pptt_processor *)entry;
 274                 }
 275 
 276                 entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
 277                                      entry->length);
 278         }
 279 
 280         return NULL;
 281 }
 282 
 283 static int acpi_find_cache_levels(struct acpi_table_header *table_hdr,
 284                                   u32 acpi_cpu_id)
 285 {
 286         int number_of_levels = 0;
 287         struct acpi_pptt_processor *cpu;
 288 
 289         cpu = acpi_find_processor_node(table_hdr, acpi_cpu_id);
 290         if (cpu)
 291                 number_of_levels = acpi_count_levels(table_hdr, cpu);
 292 
 293         return number_of_levels;
 294 }
 295 
 296 static u8 acpi_cache_type(enum cache_type type)
 297 {
 298         switch (type) {
 299         case CACHE_TYPE_DATA:
 300                 pr_debug("Looking for data cache\n");
 301                 return ACPI_PPTT_CACHE_TYPE_DATA;
 302         case CACHE_TYPE_INST:
 303                 pr_debug("Looking for instruction cache\n");
 304                 return ACPI_PPTT_CACHE_TYPE_INSTR;
 305         default:
 306         case CACHE_TYPE_UNIFIED:
 307                 pr_debug("Looking for unified cache\n");
 308                 /*
 309                  * It is important that ACPI_PPTT_CACHE_TYPE_UNIFIED
 310                  * contains the bit pattern that will match both
 311                  * ACPI unified bit patterns because we use it later
 312                  * to match both cases.
 313                  */
 314                 return ACPI_PPTT_CACHE_TYPE_UNIFIED;
 315         }
 316 }
 317 
 318 static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *table_hdr,
 319                                                     u32 acpi_cpu_id,
 320                                                     enum cache_type type,
 321                                                     unsigned int level,
 322                                                     struct acpi_pptt_processor **node)
 323 {
 324         int total_levels = 0;
 325         struct acpi_pptt_cache *found = NULL;
 326         struct acpi_pptt_processor *cpu_node;
 327         u8 acpi_type = acpi_cache_type(type);
 328 
 329         pr_debug("Looking for CPU %d's level %d cache type %d\n",
 330                  acpi_cpu_id, level, acpi_type);
 331 
 332         cpu_node = acpi_find_processor_node(table_hdr, acpi_cpu_id);
 333 
 334         while (cpu_node && !found) {
 335                 found = acpi_find_cache_level(table_hdr, cpu_node,
 336                                               &total_levels, level, acpi_type);
 337                 *node = cpu_node;
 338                 cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
 339         }
 340 
 341         return found;
 342 }
 343 
 344 /**
 345  * update_cache_properties() - Update cacheinfo for the given processor
 346  * @this_leaf: Kernel cache info structure being updated
 347  * @found_cache: The PPTT node describing this cache instance
 348  * @cpu_node: A unique reference to describe this cache instance
 349  *
 350  * The ACPI spec implies that the fields in the cache structures are used to
 351  * extend and correct the information probed from the hardware. Lets only
 352  * set fields that we determine are VALID.
 353  *
 354  * Return: nothing. Side effect of updating the global cacheinfo
 355  */
 356 static void update_cache_properties(struct cacheinfo *this_leaf,
 357                                     struct acpi_pptt_cache *found_cache,
 358                                     struct acpi_pptt_processor *cpu_node)
 359 {
 360         this_leaf->fw_token = cpu_node;
 361         if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
 362                 this_leaf->size = found_cache->size;
 363         if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
 364                 this_leaf->coherency_line_size = found_cache->line_size;
 365         if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
 366                 this_leaf->number_of_sets = found_cache->number_of_sets;
 367         if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
 368                 this_leaf->ways_of_associativity = found_cache->associativity;
 369         if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
 370                 switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
 371                 case ACPI_PPTT_CACHE_POLICY_WT:
 372                         this_leaf->attributes = CACHE_WRITE_THROUGH;
 373                         break;
 374                 case ACPI_PPTT_CACHE_POLICY_WB:
 375                         this_leaf->attributes = CACHE_WRITE_BACK;
 376                         break;
 377                 }
 378         }
 379         if (found_cache->flags & ACPI_PPTT_ALLOCATION_TYPE_VALID) {
 380                 switch (found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE) {
 381                 case ACPI_PPTT_CACHE_READ_ALLOCATE:
 382                         this_leaf->attributes |= CACHE_READ_ALLOCATE;
 383                         break;
 384                 case ACPI_PPTT_CACHE_WRITE_ALLOCATE:
 385                         this_leaf->attributes |= CACHE_WRITE_ALLOCATE;
 386                         break;
 387                 case ACPI_PPTT_CACHE_RW_ALLOCATE:
 388                 case ACPI_PPTT_CACHE_RW_ALLOCATE_ALT:
 389                         this_leaf->attributes |=
 390                                 CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE;
 391                         break;
 392                 }
 393         }
 394         /*
 395          * If cache type is NOCACHE, then the cache hasn't been specified
 396          * via other mechanisms.  Update the type if a cache type has been
 397          * provided.
 398          *
 399          * Note, we assume such caches are unified based on conventional system
 400          * design and known examples.  Significant work is required elsewhere to
 401          * fully support data/instruction only type caches which are only
 402          * specified in PPTT.
 403          */
 404         if (this_leaf->type == CACHE_TYPE_NOCACHE &&
 405             found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
 406                 this_leaf->type = CACHE_TYPE_UNIFIED;
 407 }
 408 
 409 static void cache_setup_acpi_cpu(struct acpi_table_header *table,
 410                                  unsigned int cpu)
 411 {
 412         struct acpi_pptt_cache *found_cache;
 413         struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
 414         u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
 415         struct cacheinfo *this_leaf;
 416         unsigned int index = 0;
 417         struct acpi_pptt_processor *cpu_node = NULL;
 418 
 419         while (index < get_cpu_cacheinfo(cpu)->num_leaves) {
 420                 this_leaf = this_cpu_ci->info_list + index;
 421                 found_cache = acpi_find_cache_node(table, acpi_cpu_id,
 422                                                    this_leaf->type,
 423                                                    this_leaf->level,
 424                                                    &cpu_node);
 425                 pr_debug("found = %p %p\n", found_cache, cpu_node);
 426                 if (found_cache)
 427                         update_cache_properties(this_leaf,
 428                                                 found_cache,
 429                                                 cpu_node);
 430 
 431                 index++;
 432         }
 433 }
 434 
 435 static bool flag_identical(struct acpi_table_header *table_hdr,
 436                            struct acpi_pptt_processor *cpu)
 437 {
 438         struct acpi_pptt_processor *next;
 439 
 440         /* heterogeneous machines must use PPTT revision > 1 */
 441         if (table_hdr->revision < 2)
 442                 return false;
 443 
 444         /* Locate the last node in the tree with IDENTICAL set */
 445         if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) {
 446                 next = fetch_pptt_node(table_hdr, cpu->parent);
 447                 if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL))
 448                         return true;
 449         }
 450 
 451         return false;
 452 }
 453 
 454 /* Passing level values greater than this will result in search termination */
 455 #define PPTT_ABORT_PACKAGE 0xFF
 456 
 457 static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr,
 458                                                            struct acpi_pptt_processor *cpu,
 459                                                            int level, int flag)
 460 {
 461         struct acpi_pptt_processor *prev_node;
 462 
 463         while (cpu && level) {
 464                 /* special case the identical flag to find last identical */
 465                 if (flag == ACPI_PPTT_ACPI_IDENTICAL) {
 466                         if (flag_identical(table_hdr, cpu))
 467                                 break;
 468                 } else if (cpu->flags & flag)
 469                         break;
 470                 pr_debug("level %d\n", level);
 471                 prev_node = fetch_pptt_node(table_hdr, cpu->parent);
 472                 if (prev_node == NULL)
 473                         break;
 474                 cpu = prev_node;
 475                 level--;
 476         }
 477         return cpu;
 478 }
 479 
 480 static void acpi_pptt_warn_missing(void)
 481 {
 482         pr_warn_once("No PPTT table found, CPU and cache topology may be inaccurate\n");
 483 }
 484 
 485 /**
 486  * topology_get_acpi_cpu_tag() - Find a unique topology value for a feature
 487  * @table: Pointer to the head of the PPTT table
 488  * @cpu: Kernel logical CPU number
 489  * @level: A level that terminates the search
 490  * @flag: A flag which terminates the search
 491  *
 492  * Get a unique value given a CPU, and a topology level, that can be
 493  * matched to determine which cpus share common topological features
 494  * at that level.
 495  *
 496  * Return: Unique value, or -ENOENT if unable to locate CPU
 497  */
 498 static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
 499                                      unsigned int cpu, int level, int flag)
 500 {
 501         struct acpi_pptt_processor *cpu_node;
 502         u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
 503 
 504         cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
 505         if (cpu_node) {
 506                 cpu_node = acpi_find_processor_tag(table, cpu_node,
 507                                                    level, flag);
 508                 /*
 509                  * As per specification if the processor structure represents
 510                  * an actual processor, then ACPI processor ID must be valid.
 511                  * For processor containers ACPI_PPTT_ACPI_PROCESSOR_ID_VALID
 512                  * should be set if the UID is valid
 513                  */
 514                 if (level == 0 ||
 515                     cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
 516                         return cpu_node->acpi_processor_id;
 517                 return ACPI_PTR_DIFF(cpu_node, table);
 518         }
 519         pr_warn_once("PPTT table found, but unable to locate core %d (%d)\n",
 520                     cpu, acpi_cpu_id);
 521         return -ENOENT;
 522 }
 523 
 524 static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
 525 {
 526         struct acpi_table_header *table;
 527         acpi_status status;
 528         int retval;
 529 
 530         status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 531         if (ACPI_FAILURE(status)) {
 532                 acpi_pptt_warn_missing();
 533                 return -ENOENT;
 534         }
 535         retval = topology_get_acpi_cpu_tag(table, cpu, level, flag);
 536         pr_debug("Topology Setup ACPI CPU %d, level %d ret = %d\n",
 537                  cpu, level, retval);
 538         acpi_put_table(table);
 539 
 540         return retval;
 541 }
 542 
 543 /**
 544  * check_acpi_cpu_flag() - Determine if CPU node has a flag set
 545  * @cpu: Kernel logical CPU number
 546  * @rev: The minimum PPTT revision defining the flag
 547  * @flag: The flag itself
 548  *
 549  * Check the node representing a CPU for a given flag.
 550  *
 551  * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
 552  *         the table revision isn't new enough.
 553  *         1, any passed flag set
 554  *         0, flag unset
 555  */
 556 static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
 557 {
 558         struct acpi_table_header *table;
 559         acpi_status status;
 560         u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
 561         struct acpi_pptt_processor *cpu_node = NULL;
 562         int ret = -ENOENT;
 563 
 564         status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 565         if (ACPI_FAILURE(status)) {
 566                 acpi_pptt_warn_missing();
 567                 return ret;
 568         }
 569 
 570         if (table->revision >= rev)
 571                 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
 572 
 573         if (cpu_node)
 574                 ret = (cpu_node->flags & flag) != 0;
 575 
 576         acpi_put_table(table);
 577 
 578         return ret;
 579 }
 580 
 581 /**
 582  * acpi_find_last_cache_level() - Determines the number of cache levels for a PE
 583  * @cpu: Kernel logical CPU number
 584  *
 585  * Given a logical CPU number, returns the number of levels of cache represented
 586  * in the PPTT. Errors caused by lack of a PPTT table, or otherwise, return 0
 587  * indicating we didn't find any cache levels.
 588  *
 589  * Return: Cache levels visible to this core.
 590  */
 591 int acpi_find_last_cache_level(unsigned int cpu)
 592 {
 593         u32 acpi_cpu_id;
 594         struct acpi_table_header *table;
 595         int number_of_levels = 0;
 596         acpi_status status;
 597 
 598         pr_debug("Cache Setup find last level CPU=%d\n", cpu);
 599 
 600         acpi_cpu_id = get_acpi_id_for_cpu(cpu);
 601         status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 602         if (ACPI_FAILURE(status)) {
 603                 acpi_pptt_warn_missing();
 604         } else {
 605                 number_of_levels = acpi_find_cache_levels(table, acpi_cpu_id);
 606                 acpi_put_table(table);
 607         }
 608         pr_debug("Cache Setup find last level level=%d\n", number_of_levels);
 609 
 610         return number_of_levels;
 611 }
 612 
 613 /**
 614  * cache_setup_acpi() - Override CPU cache topology with data from the PPTT
 615  * @cpu: Kernel logical CPU number
 616  *
 617  * Updates the global cache info provided by cpu_get_cacheinfo()
 618  * when there are valid properties in the acpi_pptt_cache nodes. A
 619  * successful parse may not result in any updates if none of the
 620  * cache levels have any valid flags set.  Further, a unique value is
 621  * associated with each known CPU cache entry. This unique value
 622  * can be used to determine whether caches are shared between CPUs.
 623  *
 624  * Return: -ENOENT on failure to find table, or 0 on success
 625  */
 626 int cache_setup_acpi(unsigned int cpu)
 627 {
 628         struct acpi_table_header *table;
 629         acpi_status status;
 630 
 631         pr_debug("Cache Setup ACPI CPU %d\n", cpu);
 632 
 633         status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 634         if (ACPI_FAILURE(status)) {
 635                 acpi_pptt_warn_missing();
 636                 return -ENOENT;
 637         }
 638 
 639         cache_setup_acpi_cpu(table, cpu);
 640         acpi_put_table(table);
 641 
 642         return status;
 643 }
 644 
 645 /**
 646  * acpi_pptt_cpu_is_thread() - Determine if CPU is a thread
 647  * @cpu: Kernel logical CPU number
 648  *
 649  * Return: 1, a thread
 650  *         0, not a thread
 651  *         -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or
 652  *         the table revision isn't new enough.
 653  */
 654 int acpi_pptt_cpu_is_thread(unsigned int cpu)
 655 {
 656         return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);
 657 }
 658 
 659 /**
 660  * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
 661  * @cpu: Kernel logical CPU number
 662  * @level: The topological level for which we would like a unique ID
 663  *
 664  * Determine a topology unique ID for each thread/core/cluster/mc_grouping
 665  * /socket/etc. This ID can then be used to group peers, which will have
 666  * matching ids.
 667  *
 668  * The search terminates when either the requested level is found or
 669  * we reach a root node. Levels beyond the termination point will return the
 670  * same unique ID. The unique id for level 0 is the acpi processor id. All
 671  * other levels beyond this use a generated value to uniquely identify
 672  * a topological feature.
 673  *
 674  * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
 675  * Otherwise returns a value which represents a unique topological feature.
 676  */
 677 int find_acpi_cpu_topology(unsigned int cpu, int level)
 678 {
 679         return find_acpi_cpu_topology_tag(cpu, level, 0);
 680 }
 681 
 682 /**
 683  * find_acpi_cpu_cache_topology() - Determine a unique cache topology value
 684  * @cpu: Kernel logical CPU number
 685  * @level: The cache level for which we would like a unique ID
 686  *
 687  * Determine a unique ID for each unified cache in the system
 688  *
 689  * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
 690  * Otherwise returns a value which represents a unique topological feature.
 691  */
 692 int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
 693 {
 694         struct acpi_table_header *table;
 695         struct acpi_pptt_cache *found_cache;
 696         acpi_status status;
 697         u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
 698         struct acpi_pptt_processor *cpu_node = NULL;
 699         int ret = -1;
 700 
 701         status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 702         if (ACPI_FAILURE(status)) {
 703                 acpi_pptt_warn_missing();
 704                 return -ENOENT;
 705         }
 706 
 707         found_cache = acpi_find_cache_node(table, acpi_cpu_id,
 708                                            CACHE_TYPE_UNIFIED,
 709                                            level,
 710                                            &cpu_node);
 711         if (found_cache)
 712                 ret = ACPI_PTR_DIFF(cpu_node, table);
 713 
 714         acpi_put_table(table);
 715 
 716         return ret;
 717 }
 718 
 719 /**
 720  * find_acpi_cpu_topology_package() - Determine a unique CPU package value
 721  * @cpu: Kernel logical CPU number
 722  *
 723  * Determine a topology unique package ID for the given CPU.
 724  * This ID can then be used to group peers, which will have matching ids.
 725  *
 726  * The search terminates when either a level is found with the PHYSICAL_PACKAGE
 727  * flag set or we reach a root node.
 728  *
 729  * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
 730  * Otherwise returns a value which represents the package for this CPU.
 731  */
 732 int find_acpi_cpu_topology_package(unsigned int cpu)
 733 {
 734         return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
 735                                           ACPI_PPTT_PHYSICAL_PACKAGE);
 736 }
 737 
 738 /**
 739  * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag
 740  * @cpu: Kernel logical CPU number
 741  *
 742  * Determine a unique heterogeneous tag for the given CPU. CPUs with the same
 743  * implementation should have matching tags.
 744  *
 745  * The returned tag can be used to group peers with identical implementation.
 746  *
 747  * The search terminates when a level is found with the identical implementation
 748  * flag set or we reach a root node.
 749  *
 750  * Due to limitations in the PPTT data structure, there may be rare situations
 751  * where two cores in a heterogeneous machine may be identical, but won't have
 752  * the same tag.
 753  *
 754  * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
 755  * Otherwise returns a value which represents a group of identical cores
 756  * similar to this CPU.
 757  */
 758 int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
 759 {
 760         return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
 761                                           ACPI_PPTT_ACPI_IDENTICAL);
 762 }