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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
24static 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
47static 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
53static 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
59static 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
74static 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 */
101static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
102 unsigned int local_level,
103 struct acpi_subtable_header *res,
104 struct acpi_pptt_cache **found,
105 unsigned 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 %u\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
135static struct acpi_pptt_cache *
136acpi_find_cache_level(struct acpi_table_header *table_hdr,
137 struct acpi_pptt_processor *cpu_node,
138 unsigned int *starting_level, unsigned int level,
139 int type)
140{
141 struct acpi_subtable_header *res;
142 unsigned int number_of_levels = *starting_level;
143 int resource = 0;
144 struct acpi_pptt_cache *ret = NULL;
145 unsigned int local_level;
146
147 /* walk down from processor node */
148 while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
149 resource++;
150
151 local_level = acpi_pptt_walk_cache(table_hdr, *starting_level,
152 res, &ret, level, type);
153 /*
154 * we are looking for the max depth. Since its potentially
155 * possible for a given node to have resources with differing
156 * depths verify that the depth we have found is the largest.
157 */
158 if (number_of_levels < local_level)
159 number_of_levels = local_level;
160 }
161 if (number_of_levels > *starting_level)
162 *starting_level = number_of_levels;
163
164 return ret;
165}
166
167/**
168 * acpi_count_levels() - Given a PPTT table, and a CPU node, count the caches
169 * @table_hdr: Pointer to the head of the PPTT table
170 * @cpu_node: processor node we wish to count caches for
171 *
172 * Given a processor node containing a processing unit, walk into it and count
173 * how many levels exist solely for it, and then walk up each level until we hit
174 * the root node (ignore the package level because it may be possible to have
175 * caches that exist across packages). Count the number of cache levels that
176 * exist at each level on the way up.
177 *
178 * Return: Total number of levels found.
179 */
180static int acpi_count_levels(struct acpi_table_header *table_hdr,
181 struct acpi_pptt_processor *cpu_node)
182{
183 int total_levels = 0;
184
185 do {
186 acpi_find_cache_level(table_hdr, cpu_node, &total_levels, 0, 0);
187 cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
188 } while (cpu_node);
189
190 return total_levels;
191}
192
193/**
194 * acpi_pptt_leaf_node() - Given a processor node, determine if its a leaf
195 * @table_hdr: Pointer to the head of the PPTT table
196 * @node: passed node is checked to see if its a leaf
197 *
198 * Determine if the *node parameter is a leaf node by iterating the
199 * PPTT table, looking for nodes which reference it.
200 *
201 * Return: 0 if we find a node referencing the passed node (or table error),
202 * or 1 if we don't.
203 */
204static int acpi_pptt_leaf_node(struct acpi_table_header *table_hdr,
205 struct acpi_pptt_processor *node)
206{
207 struct acpi_subtable_header *entry;
208 unsigned long table_end;
209 u32 node_entry;
210 struct acpi_pptt_processor *cpu_node;
211 u32 proc_sz;
212
213 if (table_hdr->revision > 1)
214 return (node->flags & ACPI_PPTT_ACPI_LEAF_NODE);
215
216 table_end = (unsigned long)table_hdr + table_hdr->length;
217 node_entry = ACPI_PTR_DIFF(node, table_hdr);
218 entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
219 sizeof(struct acpi_table_pptt));
220 proc_sz = sizeof(struct acpi_pptt_processor *);
221
222 while ((unsigned long)entry + proc_sz < table_end) {
223 cpu_node = (struct acpi_pptt_processor *)entry;
224 if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
225 cpu_node->parent == node_entry)
226 return 0;
227 if (entry->length == 0)
228 return 0;
229 entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
230 entry->length);
231
232 }
233 return 1;
234}
235
236/**
237 * acpi_find_processor_node() - Given a PPTT table find the requested processor
238 * @table_hdr: Pointer to the head of the PPTT table
239 * @acpi_cpu_id: CPU we are searching for
240 *
241 * Find the subtable entry describing the provided processor.
242 * This is done by iterating the PPTT table looking for processor nodes
243 * which have an acpi_processor_id that matches the acpi_cpu_id parameter
244 * passed into the function. If we find a node that matches this criteria
245 * we verify that its a leaf node in the topology rather than depending
246 * on the valid flag, which doesn't need to be set for leaf nodes.
247 *
248 * Return: NULL, or the processors acpi_pptt_processor*
249 */
250static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_header *table_hdr,
251 u32 acpi_cpu_id)
252{
253 struct acpi_subtable_header *entry;
254 unsigned long table_end;
255 struct acpi_pptt_processor *cpu_node;
256 u32 proc_sz;
257
258 table_end = (unsigned long)table_hdr + table_hdr->length;
259 entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
260 sizeof(struct acpi_table_pptt));
261 proc_sz = sizeof(struct acpi_pptt_processor *);
262
263 /* find the processor structure associated with this cpuid */
264 while ((unsigned long)entry + proc_sz < table_end) {
265 cpu_node = (struct acpi_pptt_processor *)entry;
266
267 if (entry->length == 0) {
268 pr_warn("Invalid zero length subtable\n");
269 break;
270 }
271 if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
272 acpi_cpu_id == cpu_node->acpi_processor_id &&
273 acpi_pptt_leaf_node(table_hdr, cpu_node)) {
274 return (struct acpi_pptt_processor *)entry;
275 }
276
277 entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
278 entry->length);
279 }
280
281 return NULL;
282}
283
284static int acpi_find_cache_levels(struct acpi_table_header *table_hdr,
285 u32 acpi_cpu_id)
286{
287 int number_of_levels = 0;
288 struct acpi_pptt_processor *cpu;
289
290 cpu = acpi_find_processor_node(table_hdr, acpi_cpu_id);
291 if (cpu)
292 number_of_levels = acpi_count_levels(table_hdr, cpu);
293
294 return number_of_levels;
295}
296
297static u8 acpi_cache_type(enum cache_type type)
298{
299 switch (type) {
300 case CACHE_TYPE_DATA:
301 pr_debug("Looking for data cache\n");
302 return ACPI_PPTT_CACHE_TYPE_DATA;
303 case CACHE_TYPE_INST:
304 pr_debug("Looking for instruction cache\n");
305 return ACPI_PPTT_CACHE_TYPE_INSTR;
306 default:
307 case CACHE_TYPE_UNIFIED:
308 pr_debug("Looking for unified cache\n");
309 /*
310 * It is important that ACPI_PPTT_CACHE_TYPE_UNIFIED
311 * contains the bit pattern that will match both
312 * ACPI unified bit patterns because we use it later
313 * to match both cases.
314 */
315 return ACPI_PPTT_CACHE_TYPE_UNIFIED;
316 }
317}
318
319static struct acpi_pptt_cache *acpi_find_cache_node(struct acpi_table_header *table_hdr,
320 u32 acpi_cpu_id,
321 enum cache_type type,
322 unsigned int level,
323 struct acpi_pptt_processor **node)
324{
325 unsigned int total_levels = 0;
326 struct acpi_pptt_cache *found = NULL;
327 struct acpi_pptt_processor *cpu_node;
328 u8 acpi_type = acpi_cache_type(type);
329
330 pr_debug("Looking for CPU %d's level %u cache type %d\n",
331 acpi_cpu_id, level, acpi_type);
332
333 cpu_node = acpi_find_processor_node(table_hdr, acpi_cpu_id);
334
335 while (cpu_node && !found) {
336 found = acpi_find_cache_level(table_hdr, cpu_node,
337 &total_levels, level, acpi_type);
338 *node = cpu_node;
339 cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
340 }
341
342 return found;
343}
344
345/**
346 * update_cache_properties() - Update cacheinfo for the given processor
347 * @this_leaf: Kernel cache info structure being updated
348 * @found_cache: The PPTT node describing this cache instance
349 * @cpu_node: A unique reference to describe this cache instance
350 *
351 * The ACPI spec implies that the fields in the cache structures are used to
352 * extend and correct the information probed from the hardware. Lets only
353 * set fields that we determine are VALID.
354 *
355 * Return: nothing. Side effect of updating the global cacheinfo
356 */
357static void update_cache_properties(struct cacheinfo *this_leaf,
358 struct acpi_pptt_cache *found_cache,
359 struct acpi_pptt_processor *cpu_node)
360{
361 this_leaf->fw_token = cpu_node;
362 if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
363 this_leaf->size = found_cache->size;
364 if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
365 this_leaf->coherency_line_size = found_cache->line_size;
366 if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
367 this_leaf->number_of_sets = found_cache->number_of_sets;
368 if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
369 this_leaf->ways_of_associativity = found_cache->associativity;
370 if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
371 switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
372 case ACPI_PPTT_CACHE_POLICY_WT:
373 this_leaf->attributes = CACHE_WRITE_THROUGH;
374 break;
375 case ACPI_PPTT_CACHE_POLICY_WB:
376 this_leaf->attributes = CACHE_WRITE_BACK;
377 break;
378 }
379 }
380 if (found_cache->flags & ACPI_PPTT_ALLOCATION_TYPE_VALID) {
381 switch (found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE) {
382 case ACPI_PPTT_CACHE_READ_ALLOCATE:
383 this_leaf->attributes |= CACHE_READ_ALLOCATE;
384 break;
385 case ACPI_PPTT_CACHE_WRITE_ALLOCATE:
386 this_leaf->attributes |= CACHE_WRITE_ALLOCATE;
387 break;
388 case ACPI_PPTT_CACHE_RW_ALLOCATE:
389 case ACPI_PPTT_CACHE_RW_ALLOCATE_ALT:
390 this_leaf->attributes |=
391 CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE;
392 break;
393 }
394 }
395 /*
396 * If cache type is NOCACHE, then the cache hasn't been specified
397 * via other mechanisms. Update the type if a cache type has been
398 * provided.
399 *
400 * Note, we assume such caches are unified based on conventional system
401 * design and known examples. Significant work is required elsewhere to
402 * fully support data/instruction only type caches which are only
403 * specified in PPTT.
404 */
405 if (this_leaf->type == CACHE_TYPE_NOCACHE &&
406 found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
407 this_leaf->type = CACHE_TYPE_UNIFIED;
408}
409
410static void cache_setup_acpi_cpu(struct acpi_table_header *table,
411 unsigned int cpu)
412{
413 struct acpi_pptt_cache *found_cache;
414 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
415 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
416 struct cacheinfo *this_leaf;
417 unsigned int index = 0;
418 struct acpi_pptt_processor *cpu_node = NULL;
419
420 while (index < get_cpu_cacheinfo(cpu)->num_leaves) {
421 this_leaf = this_cpu_ci->info_list + index;
422 found_cache = acpi_find_cache_node(table, acpi_cpu_id,
423 this_leaf->type,
424 this_leaf->level,
425 &cpu_node);
426 pr_debug("found = %p %p\n", found_cache, cpu_node);
427 if (found_cache)
428 update_cache_properties(this_leaf,
429 found_cache,
430 cpu_node);
431
432 index++;
433 }
434}
435
436static bool flag_identical(struct acpi_table_header *table_hdr,
437 struct acpi_pptt_processor *cpu)
438{
439 struct acpi_pptt_processor *next;
440
441 /* heterogeneous machines must use PPTT revision > 1 */
442 if (table_hdr->revision < 2)
443 return false;
444
445 /* Locate the last node in the tree with IDENTICAL set */
446 if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) {
447 next = fetch_pptt_node(table_hdr, cpu->parent);
448 if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL))
449 return true;
450 }
451
452 return false;
453}
454
455/* Passing level values greater than this will result in search termination */
456#define PPTT_ABORT_PACKAGE 0xFF
457
458static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr,
459 struct acpi_pptt_processor *cpu,
460 int level, int flag)
461{
462 struct acpi_pptt_processor *prev_node;
463
464 while (cpu && level) {
465 /* special case the identical flag to find last identical */
466 if (flag == ACPI_PPTT_ACPI_IDENTICAL) {
467 if (flag_identical(table_hdr, cpu))
468 break;
469 } else if (cpu->flags & flag)
470 break;
471 pr_debug("level %d\n", level);
472 prev_node = fetch_pptt_node(table_hdr, cpu->parent);
473 if (prev_node == NULL)
474 break;
475 cpu = prev_node;
476 level--;
477 }
478 return cpu;
479}
480
481static void acpi_pptt_warn_missing(void)
482{
483 pr_warn_once("No PPTT table found, CPU and cache topology may be inaccurate\n");
484}
485
486/**
487 * topology_get_acpi_cpu_tag() - Find a unique topology value for a feature
488 * @table: Pointer to the head of the PPTT table
489 * @cpu: Kernel logical CPU number
490 * @level: A level that terminates the search
491 * @flag: A flag which terminates the search
492 *
493 * Get a unique value given a CPU, and a topology level, that can be
494 * matched to determine which cpus share common topological features
495 * at that level.
496 *
497 * Return: Unique value, or -ENOENT if unable to locate CPU
498 */
499static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
500 unsigned int cpu, int level, int flag)
501{
502 struct acpi_pptt_processor *cpu_node;
503 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
504
505 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
506 if (cpu_node) {
507 cpu_node = acpi_find_processor_tag(table, cpu_node,
508 level, flag);
509 /*
510 * As per specification if the processor structure represents
511 * an actual processor, then ACPI processor ID must be valid.
512 * For processor containers ACPI_PPTT_ACPI_PROCESSOR_ID_VALID
513 * should be set if the UID is valid
514 */
515 if (level == 0 ||
516 cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
517 return cpu_node->acpi_processor_id;
518 return ACPI_PTR_DIFF(cpu_node, table);
519 }
520 pr_warn_once("PPTT table found, but unable to locate core %d (%d)\n",
521 cpu, acpi_cpu_id);
522 return -ENOENT;
523}
524
525static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
526{
527 struct acpi_table_header *table;
528 acpi_status status;
529 int retval;
530
531 status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
532 if (ACPI_FAILURE(status)) {
533 acpi_pptt_warn_missing();
534 return -ENOENT;
535 }
536 retval = topology_get_acpi_cpu_tag(table, cpu, level, flag);
537 pr_debug("Topology Setup ACPI CPU %d, level %d ret = %d\n",
538 cpu, level, retval);
539 acpi_put_table(table);
540
541 return retval;
542}
543
544/**
545 * check_acpi_cpu_flag() - Determine if CPU node has a flag set
546 * @cpu: Kernel logical CPU number
547 * @rev: The minimum PPTT revision defining the flag
548 * @flag: The flag itself
549 *
550 * Check the node representing a CPU for a given flag.
551 *
552 * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
553 * the table revision isn't new enough.
554 * 1, any passed flag set
555 * 0, flag unset
556 */
557static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
558{
559 struct acpi_table_header *table;
560 acpi_status status;
561 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
562 struct acpi_pptt_processor *cpu_node = NULL;
563 int ret = -ENOENT;
564
565 status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
566 if (ACPI_FAILURE(status)) {
567 acpi_pptt_warn_missing();
568 return ret;
569 }
570
571 if (table->revision >= rev)
572 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
573
574 if (cpu_node)
575 ret = (cpu_node->flags & flag) != 0;
576
577 acpi_put_table(table);
578
579 return ret;
580}
581
582/**
583 * acpi_find_last_cache_level() - Determines the number of cache levels for a PE
584 * @cpu: Kernel logical CPU number
585 *
586 * Given a logical CPU number, returns the number of levels of cache represented
587 * in the PPTT. Errors caused by lack of a PPTT table, or otherwise, return 0
588 * indicating we didn't find any cache levels.
589 *
590 * Return: Cache levels visible to this core.
591 */
592int acpi_find_last_cache_level(unsigned int cpu)
593{
594 u32 acpi_cpu_id;
595 struct acpi_table_header *table;
596 int number_of_levels = 0;
597 acpi_status status;
598
599 pr_debug("Cache Setup find last level CPU=%d\n", cpu);
600
601 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
602 status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
603 if (ACPI_FAILURE(status)) {
604 acpi_pptt_warn_missing();
605 } else {
606 number_of_levels = acpi_find_cache_levels(table, acpi_cpu_id);
607 acpi_put_table(table);
608 }
609 pr_debug("Cache Setup find last level level=%d\n", number_of_levels);
610
611 return number_of_levels;
612}
613
614/**
615 * cache_setup_acpi() - Override CPU cache topology with data from the PPTT
616 * @cpu: Kernel logical CPU number
617 *
618 * Updates the global cache info provided by cpu_get_cacheinfo()
619 * when there are valid properties in the acpi_pptt_cache nodes. A
620 * successful parse may not result in any updates if none of the
621 * cache levels have any valid flags set. Further, a unique value is
622 * associated with each known CPU cache entry. This unique value
623 * can be used to determine whether caches are shared between CPUs.
624 *
625 * Return: -ENOENT on failure to find table, or 0 on success
626 */
627int cache_setup_acpi(unsigned int cpu)
628{
629 struct acpi_table_header *table;
630 acpi_status status;
631
632 pr_debug("Cache Setup ACPI CPU %d\n", cpu);
633
634 status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
635 if (ACPI_FAILURE(status)) {
636 acpi_pptt_warn_missing();
637 return -ENOENT;
638 }
639
640 cache_setup_acpi_cpu(table, cpu);
641 acpi_put_table(table);
642
643 return status;
644}
645
646/**
647 * acpi_pptt_cpu_is_thread() - Determine if CPU is a thread
648 * @cpu: Kernel logical CPU number
649 *
650 * Return: 1, a thread
651 * 0, not a thread
652 * -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or
653 * the table revision isn't new enough.
654 */
655int acpi_pptt_cpu_is_thread(unsigned int cpu)
656{
657 return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);
658}
659
660/**
661 * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
662 * @cpu: Kernel logical CPU number
663 * @level: The topological level for which we would like a unique ID
664 *
665 * Determine a topology unique ID for each thread/core/cluster/mc_grouping
666 * /socket/etc. This ID can then be used to group peers, which will have
667 * matching ids.
668 *
669 * The search terminates when either the requested level is found or
670 * we reach a root node. Levels beyond the termination point will return the
671 * same unique ID. The unique id for level 0 is the acpi processor id. All
672 * other levels beyond this use a generated value to uniquely identify
673 * a topological feature.
674 *
675 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
676 * Otherwise returns a value which represents a unique topological feature.
677 */
678int find_acpi_cpu_topology(unsigned int cpu, int level)
679{
680 return find_acpi_cpu_topology_tag(cpu, level, 0);
681}
682
683/**
684 * find_acpi_cpu_cache_topology() - Determine a unique cache topology value
685 * @cpu: Kernel logical CPU number
686 * @level: The cache level for which we would like a unique ID
687 *
688 * Determine a unique ID for each unified cache in the system
689 *
690 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
691 * Otherwise returns a value which represents a unique topological feature.
692 */
693int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
694{
695 struct acpi_table_header *table;
696 struct acpi_pptt_cache *found_cache;
697 acpi_status status;
698 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
699 struct acpi_pptt_processor *cpu_node = NULL;
700 int ret = -1;
701
702 status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
703 if (ACPI_FAILURE(status)) {
704 acpi_pptt_warn_missing();
705 return -ENOENT;
706 }
707
708 found_cache = acpi_find_cache_node(table, acpi_cpu_id,
709 CACHE_TYPE_UNIFIED,
710 level,
711 &cpu_node);
712 if (found_cache)
713 ret = ACPI_PTR_DIFF(cpu_node, table);
714
715 acpi_put_table(table);
716
717 return ret;
718}
719
720/**
721 * find_acpi_cpu_topology_package() - Determine a unique CPU package value
722 * @cpu: Kernel logical CPU number
723 *
724 * Determine a topology unique package ID for the given CPU.
725 * This ID can then be used to group peers, which will have matching ids.
726 *
727 * The search terminates when either a level is found with the PHYSICAL_PACKAGE
728 * flag set or we reach a root node.
729 *
730 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
731 * Otherwise returns a value which represents the package for this CPU.
732 */
733int find_acpi_cpu_topology_package(unsigned int cpu)
734{
735 return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
736 ACPI_PPTT_PHYSICAL_PACKAGE);
737}
738
739/**
740 * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag
741 * @cpu: Kernel logical CPU number
742 *
743 * Determine a unique heterogeneous tag for the given CPU. CPUs with the same
744 * implementation should have matching tags.
745 *
746 * The returned tag can be used to group peers with identical implementation.
747 *
748 * The search terminates when a level is found with the identical implementation
749 * flag set or we reach a root node.
750 *
751 * Due to limitations in the PPTT data structure, there may be rare situations
752 * where two cores in a heterogeneous machine may be identical, but won't have
753 * the same tag.
754 *
755 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
756 * Otherwise returns a value which represents a group of identical cores
757 * similar to this CPU.
758 */
759int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
760{
761 return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
762 ACPI_PPTT_ACPI_IDENTICAL);
763}
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
24static 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
47static 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
53static 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
59static 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
74static 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 * @split_levels: Number of split cache levels (data/instruction).
85 * @res: cache resource in the PPTT we want to walk
86 * @found: returns a pointer to the requested level if found
87 * @level: the requested cache level
88 * @type: the requested cache type
89 *
90 * Attempt to find a given cache level, while counting the max number
91 * of cache levels for the cache node.
92 *
93 * Given a pptt resource, verify that it is a cache node, then walk
94 * down each level of caches, counting how many levels are found
95 * as well as checking the cache type (icache, dcache, unified). If a
96 * level & type match, then we set found, and continue the search.
97 * Once the entire cache branch has been walked return its max
98 * depth.
99 *
100 * Return: The cache structure and the level we terminated with.
101 */
102static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
103 unsigned int local_level,
104 unsigned int *split_levels,
105 struct acpi_subtable_header *res,
106 struct acpi_pptt_cache **found,
107 unsigned int level, int type)
108{
109 struct acpi_pptt_cache *cache;
110
111 if (res->type != ACPI_PPTT_TYPE_CACHE)
112 return 0;
113
114 cache = (struct acpi_pptt_cache *) res;
115 while (cache) {
116 local_level++;
117
118 if (!(cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)) {
119 cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache);
120 continue;
121 }
122
123 if (split_levels &&
124 (acpi_pptt_match_type(cache->attributes, ACPI_PPTT_CACHE_TYPE_DATA) ||
125 acpi_pptt_match_type(cache->attributes, ACPI_PPTT_CACHE_TYPE_INSTR)))
126 *split_levels = local_level;
127
128 if (local_level == level &&
129 acpi_pptt_match_type(cache->attributes, type)) {
130 if (*found != NULL && cache != *found)
131 pr_warn("Found duplicate cache level/type unable to determine uniqueness\n");
132
133 pr_debug("Found cache @ level %u\n", level);
134 *found = cache;
135 /*
136 * continue looking at this node's resource list
137 * to verify that we don't find a duplicate
138 * cache node.
139 */
140 }
141 cache = fetch_pptt_cache(table_hdr, cache->next_level_of_cache);
142 }
143 return local_level;
144}
145
146static struct acpi_pptt_cache *
147acpi_find_cache_level(struct acpi_table_header *table_hdr,
148 struct acpi_pptt_processor *cpu_node,
149 unsigned int *starting_level, unsigned int *split_levels,
150 unsigned int level, int type)
151{
152 struct acpi_subtable_header *res;
153 unsigned int number_of_levels = *starting_level;
154 int resource = 0;
155 struct acpi_pptt_cache *ret = NULL;
156 unsigned int local_level;
157
158 /* walk down from processor node */
159 while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
160 resource++;
161
162 local_level = acpi_pptt_walk_cache(table_hdr, *starting_level,
163 split_levels, res, &ret,
164 level, type);
165 /*
166 * we are looking for the max depth. Since its potentially
167 * possible for a given node to have resources with differing
168 * depths verify that the depth we have found is the largest.
169 */
170 if (number_of_levels < local_level)
171 number_of_levels = local_level;
172 }
173 if (number_of_levels > *starting_level)
174 *starting_level = number_of_levels;
175
176 return ret;
177}
178
179/**
180 * acpi_count_levels() - Given a PPTT table, and a CPU node, count the cache
181 * levels and split cache levels (data/instruction).
182 * @table_hdr: Pointer to the head of the PPTT table
183 * @cpu_node: processor node we wish to count caches for
184 * @levels: Number of levels if success.
185 * @split_levels: Number of split cache levels (data/instruction) if
186 * success. Can by NULL.
187 *
188 * Given a processor node containing a processing unit, walk into it and count
189 * how many levels exist solely for it, and then walk up each level until we hit
190 * the root node (ignore the package level because it may be possible to have
191 * caches that exist across packages). Count the number of cache levels and
192 * split cache levels (data/instruction) that exist at each level on the way
193 * up.
194 */
195static void acpi_count_levels(struct acpi_table_header *table_hdr,
196 struct acpi_pptt_processor *cpu_node,
197 unsigned int *levels, unsigned int *split_levels)
198{
199 do {
200 acpi_find_cache_level(table_hdr, cpu_node, levels, split_levels, 0, 0);
201 cpu_node = fetch_pptt_node(table_hdr, cpu_node->parent);
202 } while (cpu_node);
203}
204
205/**
206 * acpi_pptt_leaf_node() - Given a processor node, determine if its a leaf
207 * @table_hdr: Pointer to the head of the PPTT table
208 * @node: passed node is checked to see if its a leaf
209 *
210 * Determine if the *node parameter is a leaf node by iterating the
211 * PPTT table, looking for nodes which reference it.
212 *
213 * Return: 0 if we find a node referencing the passed node (or table error),
214 * or 1 if we don't.
215 */
216static int acpi_pptt_leaf_node(struct acpi_table_header *table_hdr,
217 struct acpi_pptt_processor *node)
218{
219 struct acpi_subtable_header *entry;
220 unsigned long table_end;
221 u32 node_entry;
222 struct acpi_pptt_processor *cpu_node;
223 u32 proc_sz;
224
225 if (table_hdr->revision > 1)
226 return (node->flags & ACPI_PPTT_ACPI_LEAF_NODE);
227
228 table_end = (unsigned long)table_hdr + table_hdr->length;
229 node_entry = ACPI_PTR_DIFF(node, table_hdr);
230 entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
231 sizeof(struct acpi_table_pptt));
232 proc_sz = sizeof(struct acpi_pptt_processor *);
233
234 while ((unsigned long)entry + proc_sz < table_end) {
235 cpu_node = (struct acpi_pptt_processor *)entry;
236 if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
237 cpu_node->parent == node_entry)
238 return 0;
239 if (entry->length == 0)
240 return 0;
241 entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
242 entry->length);
243
244 }
245 return 1;
246}
247
248/**
249 * acpi_find_processor_node() - Given a PPTT table find the requested processor
250 * @table_hdr: Pointer to the head of the PPTT table
251 * @acpi_cpu_id: CPU we are searching for
252 *
253 * Find the subtable entry describing the provided processor.
254 * This is done by iterating the PPTT table looking for processor nodes
255 * which have an acpi_processor_id that matches the acpi_cpu_id parameter
256 * passed into the function. If we find a node that matches this criteria
257 * we verify that its a leaf node in the topology rather than depending
258 * on the valid flag, which doesn't need to be set for leaf nodes.
259 *
260 * Return: NULL, or the processors acpi_pptt_processor*
261 */
262static struct acpi_pptt_processor *acpi_find_processor_node(struct acpi_table_header *table_hdr,
263 u32 acpi_cpu_id)
264{
265 struct acpi_subtable_header *entry;
266 unsigned long table_end;
267 struct acpi_pptt_processor *cpu_node;
268 u32 proc_sz;
269
270 table_end = (unsigned long)table_hdr + table_hdr->length;
271 entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
272 sizeof(struct acpi_table_pptt));
273 proc_sz = sizeof(struct acpi_pptt_processor *);
274
275 /* find the processor structure associated with this cpuid */
276 while ((unsigned long)entry + proc_sz < table_end) {
277 cpu_node = (struct acpi_pptt_processor *)entry;
278
279 if (entry->length == 0) {
280 pr_warn("Invalid zero length subtable\n");
281 break;
282 }
283 if (entry->type == ACPI_PPTT_TYPE_PROCESSOR &&
284 acpi_cpu_id == cpu_node->acpi_processor_id &&
285 acpi_pptt_leaf_node(table_hdr, cpu_node)) {
286 return (struct acpi_pptt_processor *)entry;
287 }
288
289 entry = ACPI_ADD_PTR(struct acpi_subtable_header, entry,
290 entry->length);
291 }
292
293 return NULL;
294}
295
296static 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
318static 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 unsigned 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 %u 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, NULL, 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 * @revision: The revision of the PPTT table
350 *
351 * The ACPI spec implies that the fields in the cache structures are used to
352 * extend and correct the information probed from the hardware. Lets only
353 * set fields that we determine are VALID.
354 *
355 * Return: nothing. Side effect of updating the global cacheinfo
356 */
357static void update_cache_properties(struct cacheinfo *this_leaf,
358 struct acpi_pptt_cache *found_cache,
359 struct acpi_pptt_processor *cpu_node,
360 u8 revision)
361{
362 struct acpi_pptt_cache_v1* found_cache_v1;
363
364 this_leaf->fw_token = cpu_node;
365 if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
366 this_leaf->size = found_cache->size;
367 if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
368 this_leaf->coherency_line_size = found_cache->line_size;
369 if (found_cache->flags & ACPI_PPTT_NUMBER_OF_SETS_VALID)
370 this_leaf->number_of_sets = found_cache->number_of_sets;
371 if (found_cache->flags & ACPI_PPTT_ASSOCIATIVITY_VALID)
372 this_leaf->ways_of_associativity = found_cache->associativity;
373 if (found_cache->flags & ACPI_PPTT_WRITE_POLICY_VALID) {
374 switch (found_cache->attributes & ACPI_PPTT_MASK_WRITE_POLICY) {
375 case ACPI_PPTT_CACHE_POLICY_WT:
376 this_leaf->attributes = CACHE_WRITE_THROUGH;
377 break;
378 case ACPI_PPTT_CACHE_POLICY_WB:
379 this_leaf->attributes = CACHE_WRITE_BACK;
380 break;
381 }
382 }
383 if (found_cache->flags & ACPI_PPTT_ALLOCATION_TYPE_VALID) {
384 switch (found_cache->attributes & ACPI_PPTT_MASK_ALLOCATION_TYPE) {
385 case ACPI_PPTT_CACHE_READ_ALLOCATE:
386 this_leaf->attributes |= CACHE_READ_ALLOCATE;
387 break;
388 case ACPI_PPTT_CACHE_WRITE_ALLOCATE:
389 this_leaf->attributes |= CACHE_WRITE_ALLOCATE;
390 break;
391 case ACPI_PPTT_CACHE_RW_ALLOCATE:
392 case ACPI_PPTT_CACHE_RW_ALLOCATE_ALT:
393 this_leaf->attributes |=
394 CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE;
395 break;
396 }
397 }
398 /*
399 * If cache type is NOCACHE, then the cache hasn't been specified
400 * via other mechanisms. Update the type if a cache type has been
401 * provided.
402 *
403 * Note, we assume such caches are unified based on conventional system
404 * design and known examples. Significant work is required elsewhere to
405 * fully support data/instruction only type caches which are only
406 * specified in PPTT.
407 */
408 if (this_leaf->type == CACHE_TYPE_NOCACHE &&
409 found_cache->flags & ACPI_PPTT_CACHE_TYPE_VALID)
410 this_leaf->type = CACHE_TYPE_UNIFIED;
411
412 if (revision >= 3 && (found_cache->flags & ACPI_PPTT_CACHE_ID_VALID)) {
413 found_cache_v1 = ACPI_ADD_PTR(struct acpi_pptt_cache_v1,
414 found_cache, sizeof(struct acpi_pptt_cache));
415 this_leaf->id = found_cache_v1->cache_id;
416 this_leaf->attributes |= CACHE_ID;
417 }
418}
419
420static void cache_setup_acpi_cpu(struct acpi_table_header *table,
421 unsigned int cpu)
422{
423 struct acpi_pptt_cache *found_cache;
424 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
425 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
426 struct cacheinfo *this_leaf;
427 unsigned int index = 0;
428 struct acpi_pptt_processor *cpu_node = NULL;
429
430 while (index < get_cpu_cacheinfo(cpu)->num_leaves) {
431 this_leaf = this_cpu_ci->info_list + index;
432 found_cache = acpi_find_cache_node(table, acpi_cpu_id,
433 this_leaf->type,
434 this_leaf->level,
435 &cpu_node);
436 pr_debug("found = %p %p\n", found_cache, cpu_node);
437 if (found_cache)
438 update_cache_properties(this_leaf, found_cache,
439 ACPI_TO_POINTER(ACPI_PTR_DIFF(cpu_node, table)),
440 table->revision);
441
442 index++;
443 }
444}
445
446static bool flag_identical(struct acpi_table_header *table_hdr,
447 struct acpi_pptt_processor *cpu)
448{
449 struct acpi_pptt_processor *next;
450
451 /* heterogeneous machines must use PPTT revision > 1 */
452 if (table_hdr->revision < 2)
453 return false;
454
455 /* Locate the last node in the tree with IDENTICAL set */
456 if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) {
457 next = fetch_pptt_node(table_hdr, cpu->parent);
458 if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL))
459 return true;
460 }
461
462 return false;
463}
464
465/* Passing level values greater than this will result in search termination */
466#define PPTT_ABORT_PACKAGE 0xFF
467
468static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr,
469 struct acpi_pptt_processor *cpu,
470 int level, int flag)
471{
472 struct acpi_pptt_processor *prev_node;
473
474 while (cpu && level) {
475 /* special case the identical flag to find last identical */
476 if (flag == ACPI_PPTT_ACPI_IDENTICAL) {
477 if (flag_identical(table_hdr, cpu))
478 break;
479 } else if (cpu->flags & flag)
480 break;
481 pr_debug("level %d\n", level);
482 prev_node = fetch_pptt_node(table_hdr, cpu->parent);
483 if (prev_node == NULL)
484 break;
485 cpu = prev_node;
486 level--;
487 }
488 return cpu;
489}
490
491static void acpi_pptt_warn_missing(void)
492{
493 pr_warn_once("No PPTT table found, CPU and cache topology may be inaccurate\n");
494}
495
496/**
497 * topology_get_acpi_cpu_tag() - Find a unique topology value for a feature
498 * @table: Pointer to the head of the PPTT table
499 * @cpu: Kernel logical CPU number
500 * @level: A level that terminates the search
501 * @flag: A flag which terminates the search
502 *
503 * Get a unique value given a CPU, and a topology level, that can be
504 * matched to determine which cpus share common topological features
505 * at that level.
506 *
507 * Return: Unique value, or -ENOENT if unable to locate CPU
508 */
509static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
510 unsigned int cpu, int level, int flag)
511{
512 struct acpi_pptt_processor *cpu_node;
513 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
514
515 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
516 if (cpu_node) {
517 cpu_node = acpi_find_processor_tag(table, cpu_node,
518 level, flag);
519 /*
520 * As per specification if the processor structure represents
521 * an actual processor, then ACPI processor ID must be valid.
522 * For processor containers ACPI_PPTT_ACPI_PROCESSOR_ID_VALID
523 * should be set if the UID is valid
524 */
525 if (level == 0 ||
526 cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
527 return cpu_node->acpi_processor_id;
528 return ACPI_PTR_DIFF(cpu_node, table);
529 }
530 pr_warn_once("PPTT table found, but unable to locate core %d (%d)\n",
531 cpu, acpi_cpu_id);
532 return -ENOENT;
533}
534
535
536static struct acpi_table_header *acpi_get_pptt(void)
537{
538 static struct acpi_table_header *pptt;
539 static bool is_pptt_checked;
540 acpi_status status;
541
542 /*
543 * PPTT will be used at runtime on every CPU hotplug in path, so we
544 * don't need to call acpi_put_table() to release the table mapping.
545 */
546 if (!pptt && !is_pptt_checked) {
547 status = acpi_get_table(ACPI_SIG_PPTT, 0, &pptt);
548 if (ACPI_FAILURE(status))
549 acpi_pptt_warn_missing();
550
551 is_pptt_checked = true;
552 }
553
554 return pptt;
555}
556
557static int find_acpi_cpu_topology_tag(unsigned int cpu, int level, int flag)
558{
559 struct acpi_table_header *table;
560 int retval;
561
562 table = acpi_get_pptt();
563 if (!table)
564 return -ENOENT;
565
566 retval = topology_get_acpi_cpu_tag(table, cpu, level, flag);
567 pr_debug("Topology Setup ACPI CPU %d, level %d ret = %d\n",
568 cpu, level, retval);
569
570 return retval;
571}
572
573/**
574 * check_acpi_cpu_flag() - Determine if CPU node has a flag set
575 * @cpu: Kernel logical CPU number
576 * @rev: The minimum PPTT revision defining the flag
577 * @flag: The flag itself
578 *
579 * Check the node representing a CPU for a given flag.
580 *
581 * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found or
582 * the table revision isn't new enough.
583 * 1, any passed flag set
584 * 0, flag unset
585 */
586static int check_acpi_cpu_flag(unsigned int cpu, int rev, u32 flag)
587{
588 struct acpi_table_header *table;
589 u32 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
590 struct acpi_pptt_processor *cpu_node = NULL;
591 int ret = -ENOENT;
592
593 table = acpi_get_pptt();
594 if (!table)
595 return -ENOENT;
596
597 if (table->revision >= rev)
598 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
599
600 if (cpu_node)
601 ret = (cpu_node->flags & flag) != 0;
602
603 return ret;
604}
605
606/**
607 * acpi_get_cache_info() - Determine the number of cache levels and
608 * split cache levels (data/instruction) and for a PE.
609 * @cpu: Kernel logical CPU number
610 * @levels: Number of levels if success.
611 * @split_levels: Number of levels being split (i.e. data/instruction)
612 * if success. Can by NULL.
613 *
614 * Given a logical CPU number, returns the number of levels of cache represented
615 * in the PPTT. Errors caused by lack of a PPTT table, or otherwise, return 0
616 * indicating we didn't find any cache levels.
617 *
618 * Return: -ENOENT if no PPTT table or no PPTT processor struct found.
619 * 0 on success.
620 */
621int acpi_get_cache_info(unsigned int cpu, unsigned int *levels,
622 unsigned int *split_levels)
623{
624 struct acpi_pptt_processor *cpu_node;
625 struct acpi_table_header *table;
626 u32 acpi_cpu_id;
627
628 *levels = 0;
629 if (split_levels)
630 *split_levels = 0;
631
632 table = acpi_get_pptt();
633 if (!table)
634 return -ENOENT;
635
636 pr_debug("Cache Setup: find cache levels for CPU=%d\n", cpu);
637
638 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
639 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
640 if (!cpu_node)
641 return -ENOENT;
642
643 acpi_count_levels(table, cpu_node, levels, split_levels);
644
645 pr_debug("Cache Setup: last_level=%d split_levels=%d\n",
646 *levels, split_levels ? *split_levels : -1);
647
648 return 0;
649}
650
651/**
652 * cache_setup_acpi() - Override CPU cache topology with data from the PPTT
653 * @cpu: Kernel logical CPU number
654 *
655 * Updates the global cache info provided by cpu_get_cacheinfo()
656 * when there are valid properties in the acpi_pptt_cache nodes. A
657 * successful parse may not result in any updates if none of the
658 * cache levels have any valid flags set. Further, a unique value is
659 * associated with each known CPU cache entry. This unique value
660 * can be used to determine whether caches are shared between CPUs.
661 *
662 * Return: -ENOENT on failure to find table, or 0 on success
663 */
664int cache_setup_acpi(unsigned int cpu)
665{
666 struct acpi_table_header *table;
667
668 table = acpi_get_pptt();
669 if (!table)
670 return -ENOENT;
671
672 pr_debug("Cache Setup ACPI CPU %d\n", cpu);
673
674 cache_setup_acpi_cpu(table, cpu);
675
676 return 0;
677}
678
679/**
680 * acpi_pptt_cpu_is_thread() - Determine if CPU is a thread
681 * @cpu: Kernel logical CPU number
682 *
683 * Return: 1, a thread
684 * 0, not a thread
685 * -ENOENT ,if the PPTT doesn't exist, the CPU cannot be found or
686 * the table revision isn't new enough.
687 */
688int acpi_pptt_cpu_is_thread(unsigned int cpu)
689{
690 return check_acpi_cpu_flag(cpu, 2, ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD);
691}
692
693/**
694 * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
695 * @cpu: Kernel logical CPU number
696 * @level: The topological level for which we would like a unique ID
697 *
698 * Determine a topology unique ID for each thread/core/cluster/mc_grouping
699 * /socket/etc. This ID can then be used to group peers, which will have
700 * matching ids.
701 *
702 * The search terminates when either the requested level is found or
703 * we reach a root node. Levels beyond the termination point will return the
704 * same unique ID. The unique id for level 0 is the acpi processor id. All
705 * other levels beyond this use a generated value to uniquely identify
706 * a topological feature.
707 *
708 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
709 * Otherwise returns a value which represents a unique topological feature.
710 */
711int find_acpi_cpu_topology(unsigned int cpu, int level)
712{
713 return find_acpi_cpu_topology_tag(cpu, level, 0);
714}
715
716/**
717 * find_acpi_cpu_topology_package() - Determine a unique CPU package value
718 * @cpu: Kernel logical CPU number
719 *
720 * Determine a topology unique package ID for the given CPU.
721 * This ID can then be used to group peers, which will have matching ids.
722 *
723 * The search terminates when either a level is found with the PHYSICAL_PACKAGE
724 * flag set or we reach a root node.
725 *
726 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
727 * Otherwise returns a value which represents the package for this CPU.
728 */
729int find_acpi_cpu_topology_package(unsigned int cpu)
730{
731 return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
732 ACPI_PPTT_PHYSICAL_PACKAGE);
733}
734
735/**
736 * find_acpi_cpu_topology_cluster() - Determine a unique CPU cluster value
737 * @cpu: Kernel logical CPU number
738 *
739 * Determine a topology unique cluster ID for the given CPU/thread.
740 * This ID can then be used to group peers, which will have matching ids.
741 *
742 * The cluster, if present is the level of topology above CPUs. In a
743 * multi-thread CPU, it will be the level above the CPU, not the thread.
744 * It may not exist in single CPU systems. In simple multi-CPU systems,
745 * it may be equal to the package topology level.
746 *
747 * Return: -ENOENT if the PPTT doesn't exist, the CPU cannot be found
748 * or there is no toplogy level above the CPU..
749 * Otherwise returns a value which represents the package for this CPU.
750 */
751
752int find_acpi_cpu_topology_cluster(unsigned int cpu)
753{
754 struct acpi_table_header *table;
755 struct acpi_pptt_processor *cpu_node, *cluster_node;
756 u32 acpi_cpu_id;
757 int retval;
758 int is_thread;
759
760 table = acpi_get_pptt();
761 if (!table)
762 return -ENOENT;
763
764 acpi_cpu_id = get_acpi_id_for_cpu(cpu);
765 cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
766 if (!cpu_node || !cpu_node->parent)
767 return -ENOENT;
768
769 is_thread = cpu_node->flags & ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD;
770 cluster_node = fetch_pptt_node(table, cpu_node->parent);
771 if (!cluster_node)
772 return -ENOENT;
773
774 if (is_thread) {
775 if (!cluster_node->parent)
776 return -ENOENT;
777
778 cluster_node = fetch_pptt_node(table, cluster_node->parent);
779 if (!cluster_node)
780 return -ENOENT;
781 }
782 if (cluster_node->flags & ACPI_PPTT_ACPI_PROCESSOR_ID_VALID)
783 retval = cluster_node->acpi_processor_id;
784 else
785 retval = ACPI_PTR_DIFF(cluster_node, table);
786
787 return retval;
788}
789
790/**
791 * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag
792 * @cpu: Kernel logical CPU number
793 *
794 * Determine a unique heterogeneous tag for the given CPU. CPUs with the same
795 * implementation should have matching tags.
796 *
797 * The returned tag can be used to group peers with identical implementation.
798 *
799 * The search terminates when a level is found with the identical implementation
800 * flag set or we reach a root node.
801 *
802 * Due to limitations in the PPTT data structure, there may be rare situations
803 * where two cores in a heterogeneous machine may be identical, but won't have
804 * the same tag.
805 *
806 * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
807 * Otherwise returns a value which represents a group of identical cores
808 * similar to this CPU.
809 */
810int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
811{
812 return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
813 ACPI_PPTT_ACPI_IDENTICAL);
814}