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Linux/arch/powerpc/kernel/cacheinfo.c

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  1 /*
  2  * Processor cache information made available to userspace via sysfs;
  3  * intended to be compatible with x86 intel_cacheinfo implementation.
  4  *
  5  * Copyright 2008 IBM Corporation
  6  * Author: Nathan Lynch
  7  *
  8  * This program is free software; you can redistribute it and/or
  9  * modify it under the terms of the GNU General Public License version
 10  * 2 as published by the Free Software Foundation.
 11  */
 12 
 13 #include <linux/cpu.h>
 14 #include <linux/cpumask.h>
 15 #include <linux/init.h>
 16 #include <linux/kernel.h>
 17 #include <linux/kobject.h>
 18 #include <linux/list.h>
 19 #include <linux/notifier.h>
 20 #include <linux/of.h>
 21 #include <linux/percpu.h>
 22 #include <linux/slab.h>
 23 #include <asm/prom.h>
 24 
 25 #include "cacheinfo.h"
 26 
 27 /* per-cpu object for tracking:
 28  * - a "cache" kobject for the top-level directory
 29  * - a list of "index" objects representing the cpu's local cache hierarchy
 30  */
 31 struct cache_dir {
 32         struct kobject *kobj; /* bare (not embedded) kobject for cache
 33                                * directory */
 34         struct cache_index_dir *index; /* list of index objects */
 35 };
 36 
 37 /* "index" object: each cpu's cache directory has an index
 38  * subdirectory corresponding to a cache object associated with the
 39  * cpu.  This object's lifetime is managed via the embedded kobject.
 40  */
 41 struct cache_index_dir {
 42         struct kobject kobj;
 43         struct cache_index_dir *next; /* next index in parent directory */
 44         struct cache *cache;
 45 };
 46 
 47 /* Template for determining which OF properties to query for a given
 48  * cache type */
 49 struct cache_type_info {
 50         const char *name;
 51         const char *size_prop;
 52 
 53         /* Allow for both [di]-cache-line-size and
 54          * [di]-cache-block-size properties.  According to the PowerPC
 55          * Processor binding, -line-size should be provided if it
 56          * differs from the cache block size (that which is operated
 57          * on by cache instructions), so we look for -line-size first.
 58          * See cache_get_line_size(). */
 59 
 60         const char *line_size_props[2];
 61         const char *nr_sets_prop;
 62 };
 63 
 64 /* These are used to index the cache_type_info array. */
 65 #define CACHE_TYPE_UNIFIED     0
 66 #define CACHE_TYPE_INSTRUCTION 1
 67 #define CACHE_TYPE_DATA        2
 68 
 69 static const struct cache_type_info cache_type_info[] = {
 70         {
 71                 /* PowerPC Processor binding says the [di]-cache-*
 72                  * must be equal on unified caches, so just use
 73                  * d-cache properties. */
 74                 .name            = "Unified",
 75                 .size_prop       = "d-cache-size",
 76                 .line_size_props = { "d-cache-line-size",
 77                                      "d-cache-block-size", },
 78                 .nr_sets_prop    = "d-cache-sets",
 79         },
 80         {
 81                 .name            = "Instruction",
 82                 .size_prop       = "i-cache-size",
 83                 .line_size_props = { "i-cache-line-size",
 84                                      "i-cache-block-size", },
 85                 .nr_sets_prop    = "i-cache-sets",
 86         },
 87         {
 88                 .name            = "Data",
 89                 .size_prop       = "d-cache-size",
 90                 .line_size_props = { "d-cache-line-size",
 91                                      "d-cache-block-size", },
 92                 .nr_sets_prop    = "d-cache-sets",
 93         },
 94 };
 95 
 96 /* Cache object: each instance of this corresponds to a distinct cache
 97  * in the system.  There are separate objects for Harvard caches: one
 98  * each for instruction and data, and each refers to the same OF node.
 99  * The refcount of the OF node is elevated for the lifetime of the
100  * cache object.  A cache object is released when its shared_cpu_map
101  * is cleared (see cache_cpu_clear).
102  *
103  * A cache object is on two lists: an unsorted global list
104  * (cache_list) of cache objects; and a singly-linked list
105  * representing the local cache hierarchy, which is ordered by level
106  * (e.g. L1d -> L1i -> L2 -> L3).
107  */
108 struct cache {
109         struct device_node *ofnode;    /* OF node for this cache, may be cpu */
110         struct cpumask shared_cpu_map; /* online CPUs using this cache */
111         int type;                      /* split cache disambiguation */
112         int level;                     /* level not explicit in device tree */
113         struct list_head list;         /* global list of cache objects */
114         struct cache *next_local;      /* next cache of >= level */
115 };
116 
117 static DEFINE_PER_CPU(struct cache_dir *, cache_dir_pcpu);
118 
119 /* traversal/modification of this list occurs only at cpu hotplug time;
120  * access is serialized by cpu hotplug locking
121  */
122 static LIST_HEAD(cache_list);
123 
124 static struct cache_index_dir *kobj_to_cache_index_dir(struct kobject *k)
125 {
126         return container_of(k, struct cache_index_dir, kobj);
127 }
128 
129 static const char *cache_type_string(const struct cache *cache)
130 {
131         return cache_type_info[cache->type].name;
132 }
133 
134 static void cache_init(struct cache *cache, int type, int level,
135                        struct device_node *ofnode)
136 {
137         cache->type = type;
138         cache->level = level;
139         cache->ofnode = of_node_get(ofnode);
140         INIT_LIST_HEAD(&cache->list);
141         list_add(&cache->list, &cache_list);
142 }
143 
144 static struct cache *new_cache(int type, int level, struct device_node *ofnode)
145 {
146         struct cache *cache;
147 
148         cache = kzalloc(sizeof(*cache), GFP_KERNEL);
149         if (cache)
150                 cache_init(cache, type, level, ofnode);
151 
152         return cache;
153 }
154 
155 static void release_cache_debugcheck(struct cache *cache)
156 {
157         struct cache *iter;
158 
159         list_for_each_entry(iter, &cache_list, list)
160                 WARN_ONCE(iter->next_local == cache,
161                           "cache for %s(%s) refers to cache for %s(%s)\n",
162                           iter->ofnode->full_name,
163                           cache_type_string(iter),
164                           cache->ofnode->full_name,
165                           cache_type_string(cache));
166 }
167 
168 static void release_cache(struct cache *cache)
169 {
170         if (!cache)
171                 return;
172 
173         pr_debug("freeing L%d %s cache for %s\n", cache->level,
174                  cache_type_string(cache), cache->ofnode->full_name);
175 
176         release_cache_debugcheck(cache);
177         list_del(&cache->list);
178         of_node_put(cache->ofnode);
179         kfree(cache);
180 }
181 
182 static void cache_cpu_set(struct cache *cache, int cpu)
183 {
184         struct cache *next = cache;
185 
186         while (next) {
187                 WARN_ONCE(cpumask_test_cpu(cpu, &next->shared_cpu_map),
188                           "CPU %i already accounted in %s(%s)\n",
189                           cpu, next->ofnode->full_name,
190                           cache_type_string(next));
191                 cpumask_set_cpu(cpu, &next->shared_cpu_map);
192                 next = next->next_local;
193         }
194 }
195 
196 static int cache_size(const struct cache *cache, unsigned int *ret)
197 {
198         const char *propname;
199         const u32 *cache_size;
200 
201         propname = cache_type_info[cache->type].size_prop;
202 
203         cache_size = of_get_property(cache->ofnode, propname, NULL);
204         if (!cache_size)
205                 return -ENODEV;
206 
207         *ret = *cache_size;
208         return 0;
209 }
210 
211 static int cache_size_kb(const struct cache *cache, unsigned int *ret)
212 {
213         unsigned int size;
214 
215         if (cache_size(cache, &size))
216                 return -ENODEV;
217 
218         *ret = size / 1024;
219         return 0;
220 }
221 
222 /* not cache_line_size() because that's a macro in include/linux/cache.h */
223 static int cache_get_line_size(const struct cache *cache, unsigned int *ret)
224 {
225         const u32 *line_size;
226         int i, lim;
227 
228         lim = ARRAY_SIZE(cache_type_info[cache->type].line_size_props);
229 
230         for (i = 0; i < lim; i++) {
231                 const char *propname;
232 
233                 propname = cache_type_info[cache->type].line_size_props[i];
234                 line_size = of_get_property(cache->ofnode, propname, NULL);
235                 if (line_size)
236                         break;
237         }
238 
239         if (!line_size)
240                 return -ENODEV;
241 
242         *ret = *line_size;
243         return 0;
244 }
245 
246 static int cache_nr_sets(const struct cache *cache, unsigned int *ret)
247 {
248         const char *propname;
249         const u32 *nr_sets;
250 
251         propname = cache_type_info[cache->type].nr_sets_prop;
252 
253         nr_sets = of_get_property(cache->ofnode, propname, NULL);
254         if (!nr_sets)
255                 return -ENODEV;
256 
257         *ret = *nr_sets;
258         return 0;
259 }
260 
261 static int cache_associativity(const struct cache *cache, unsigned int *ret)
262 {
263         unsigned int line_size;
264         unsigned int nr_sets;
265         unsigned int size;
266 
267         if (cache_nr_sets(cache, &nr_sets))
268                 goto err;
269 
270         /* If the cache is fully associative, there is no need to
271          * check the other properties.
272          */
273         if (nr_sets == 1) {
274                 *ret = 0;
275                 return 0;
276         }
277 
278         if (cache_get_line_size(cache, &line_size))
279                 goto err;
280         if (cache_size(cache, &size))
281                 goto err;
282 
283         if (!(nr_sets > 0 && size > 0 && line_size > 0))
284                 goto err;
285 
286         *ret = (size / nr_sets) / line_size;
287         return 0;
288 err:
289         return -ENODEV;
290 }
291 
292 /* helper for dealing with split caches */
293 static struct cache *cache_find_first_sibling(struct cache *cache)
294 {
295         struct cache *iter;
296 
297         if (cache->type == CACHE_TYPE_UNIFIED)
298                 return cache;
299 
300         list_for_each_entry(iter, &cache_list, list)
301                 if (iter->ofnode == cache->ofnode && iter->next_local == cache)
302                         return iter;
303 
304         return cache;
305 }
306 
307 /* return the first cache on a local list matching node */
308 static struct cache *cache_lookup_by_node(const struct device_node *node)
309 {
310         struct cache *cache = NULL;
311         struct cache *iter;
312 
313         list_for_each_entry(iter, &cache_list, list) {
314                 if (iter->ofnode != node)
315                         continue;
316                 cache = cache_find_first_sibling(iter);
317                 break;
318         }
319 
320         return cache;
321 }
322 
323 static bool cache_node_is_unified(const struct device_node *np)
324 {
325         return of_get_property(np, "cache-unified", NULL);
326 }
327 
328 static struct cache *cache_do_one_devnode_unified(struct device_node *node,
329                                                   int level)
330 {
331         struct cache *cache;
332 
333         pr_debug("creating L%d ucache for %s\n", level, node->full_name);
334 
335         cache = new_cache(CACHE_TYPE_UNIFIED, level, node);
336 
337         return cache;
338 }
339 
340 static struct cache *cache_do_one_devnode_split(struct device_node *node,
341                                                 int level)
342 {
343         struct cache *dcache, *icache;
344 
345         pr_debug("creating L%d dcache and icache for %s\n", level,
346                  node->full_name);
347 
348         dcache = new_cache(CACHE_TYPE_DATA, level, node);
349         icache = new_cache(CACHE_TYPE_INSTRUCTION, level, node);
350 
351         if (!dcache || !icache)
352                 goto err;
353 
354         dcache->next_local = icache;
355 
356         return dcache;
357 err:
358         release_cache(dcache);
359         release_cache(icache);
360         return NULL;
361 }
362 
363 static struct cache *cache_do_one_devnode(struct device_node *node, int level)
364 {
365         struct cache *cache;
366 
367         if (cache_node_is_unified(node))
368                 cache = cache_do_one_devnode_unified(node, level);
369         else
370                 cache = cache_do_one_devnode_split(node, level);
371 
372         return cache;
373 }
374 
375 static struct cache *cache_lookup_or_instantiate(struct device_node *node,
376                                                  int level)
377 {
378         struct cache *cache;
379 
380         cache = cache_lookup_by_node(node);
381 
382         WARN_ONCE(cache && cache->level != level,
383                   "cache level mismatch on lookup (got %d, expected %d)\n",
384                   cache->level, level);
385 
386         if (!cache)
387                 cache = cache_do_one_devnode(node, level);
388 
389         return cache;
390 }
391 
392 static void link_cache_lists(struct cache *smaller, struct cache *bigger)
393 {
394         while (smaller->next_local) {
395                 if (smaller->next_local == bigger)
396                         return; /* already linked */
397                 smaller = smaller->next_local;
398         }
399 
400         smaller->next_local = bigger;
401 }
402 
403 static void do_subsidiary_caches_debugcheck(struct cache *cache)
404 {
405         WARN_ON_ONCE(cache->level != 1);
406         WARN_ON_ONCE(strcmp(cache->ofnode->type, "cpu"));
407 }
408 
409 static void do_subsidiary_caches(struct cache *cache)
410 {
411         struct device_node *subcache_node;
412         int level = cache->level;
413 
414         do_subsidiary_caches_debugcheck(cache);
415 
416         while ((subcache_node = of_find_next_cache_node(cache->ofnode))) {
417                 struct cache *subcache;
418 
419                 level++;
420                 subcache = cache_lookup_or_instantiate(subcache_node, level);
421                 of_node_put(subcache_node);
422                 if (!subcache)
423                         break;
424 
425                 link_cache_lists(cache, subcache);
426                 cache = subcache;
427         }
428 }
429 
430 static struct cache *cache_chain_instantiate(unsigned int cpu_id)
431 {
432         struct device_node *cpu_node;
433         struct cache *cpu_cache = NULL;
434 
435         pr_debug("creating cache object(s) for CPU %i\n", cpu_id);
436 
437         cpu_node = of_get_cpu_node(cpu_id, NULL);
438         WARN_ONCE(!cpu_node, "no OF node found for CPU %i\n", cpu_id);
439         if (!cpu_node)
440                 goto out;
441 
442         cpu_cache = cache_lookup_or_instantiate(cpu_node, 1);
443         if (!cpu_cache)
444                 goto out;
445 
446         do_subsidiary_caches(cpu_cache);
447 
448         cache_cpu_set(cpu_cache, cpu_id);
449 out:
450         of_node_put(cpu_node);
451 
452         return cpu_cache;
453 }
454 
455 static struct cache_dir *cacheinfo_create_cache_dir(unsigned int cpu_id)
456 {
457         struct cache_dir *cache_dir;
458         struct device *dev;
459         struct kobject *kobj = NULL;
460 
461         dev = get_cpu_device(cpu_id);
462         WARN_ONCE(!dev, "no dev for CPU %i\n", cpu_id);
463         if (!dev)
464                 goto err;
465 
466         kobj = kobject_create_and_add("cache", &dev->kobj);
467         if (!kobj)
468                 goto err;
469 
470         cache_dir = kzalloc(sizeof(*cache_dir), GFP_KERNEL);
471         if (!cache_dir)
472                 goto err;
473 
474         cache_dir->kobj = kobj;
475 
476         WARN_ON_ONCE(per_cpu(cache_dir_pcpu, cpu_id) != NULL);
477 
478         per_cpu(cache_dir_pcpu, cpu_id) = cache_dir;
479 
480         return cache_dir;
481 err:
482         kobject_put(kobj);
483         return NULL;
484 }
485 
486 static void cache_index_release(struct kobject *kobj)
487 {
488         struct cache_index_dir *index;
489 
490         index = kobj_to_cache_index_dir(kobj);
491 
492         pr_debug("freeing index directory for L%d %s cache\n",
493                  index->cache->level, cache_type_string(index->cache));
494 
495         kfree(index);
496 }
497 
498 static ssize_t cache_index_show(struct kobject *k, struct attribute *attr, char *buf)
499 {
500         struct kobj_attribute *kobj_attr;
501 
502         kobj_attr = container_of(attr, struct kobj_attribute, attr);
503 
504         return kobj_attr->show(k, kobj_attr, buf);
505 }
506 
507 static struct cache *index_kobj_to_cache(struct kobject *k)
508 {
509         struct cache_index_dir *index;
510 
511         index = kobj_to_cache_index_dir(k);
512 
513         return index->cache;
514 }
515 
516 static ssize_t size_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
517 {
518         unsigned int size_kb;
519         struct cache *cache;
520 
521         cache = index_kobj_to_cache(k);
522 
523         if (cache_size_kb(cache, &size_kb))
524                 return -ENODEV;
525 
526         return sprintf(buf, "%uK\n", size_kb);
527 }
528 
529 static struct kobj_attribute cache_size_attr =
530         __ATTR(size, 0444, size_show, NULL);
531 
532 
533 static ssize_t line_size_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
534 {
535         unsigned int line_size;
536         struct cache *cache;
537 
538         cache = index_kobj_to_cache(k);
539 
540         if (cache_get_line_size(cache, &line_size))
541                 return -ENODEV;
542 
543         return sprintf(buf, "%u\n", line_size);
544 }
545 
546 static struct kobj_attribute cache_line_size_attr =
547         __ATTR(coherency_line_size, 0444, line_size_show, NULL);
548 
549 static ssize_t nr_sets_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
550 {
551         unsigned int nr_sets;
552         struct cache *cache;
553 
554         cache = index_kobj_to_cache(k);
555 
556         if (cache_nr_sets(cache, &nr_sets))
557                 return -ENODEV;
558 
559         return sprintf(buf, "%u\n", nr_sets);
560 }
561 
562 static struct kobj_attribute cache_nr_sets_attr =
563         __ATTR(number_of_sets, 0444, nr_sets_show, NULL);
564 
565 static ssize_t associativity_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
566 {
567         unsigned int associativity;
568         struct cache *cache;
569 
570         cache = index_kobj_to_cache(k);
571 
572         if (cache_associativity(cache, &associativity))
573                 return -ENODEV;
574 
575         return sprintf(buf, "%u\n", associativity);
576 }
577 
578 static struct kobj_attribute cache_assoc_attr =
579         __ATTR(ways_of_associativity, 0444, associativity_show, NULL);
580 
581 static ssize_t type_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
582 {
583         struct cache *cache;
584 
585         cache = index_kobj_to_cache(k);
586 
587         return sprintf(buf, "%s\n", cache_type_string(cache));
588 }
589 
590 static struct kobj_attribute cache_type_attr =
591         __ATTR(type, 0444, type_show, NULL);
592 
593 static ssize_t level_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
594 {
595         struct cache_index_dir *index;
596         struct cache *cache;
597 
598         index = kobj_to_cache_index_dir(k);
599         cache = index->cache;
600 
601         return sprintf(buf, "%d\n", cache->level);
602 }
603 
604 static struct kobj_attribute cache_level_attr =
605         __ATTR(level, 0444, level_show, NULL);
606 
607 static ssize_t shared_cpu_map_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
608 {
609         struct cache_index_dir *index;
610         struct cache *cache;
611         int len;
612         int n = 0;
613 
614         index = kobj_to_cache_index_dir(k);
615         cache = index->cache;
616         len = PAGE_SIZE - 2;
617 
618         if (len > 1) {
619                 n = cpumask_scnprintf(buf, len, &cache->shared_cpu_map);
620                 buf[n++] = '\n';
621                 buf[n] = '\0';
622         }
623         return n;
624 }
625 
626 static struct kobj_attribute cache_shared_cpu_map_attr =
627         __ATTR(shared_cpu_map, 0444, shared_cpu_map_show, NULL);
628 
629 /* Attributes which should always be created -- the kobject/sysfs core
630  * does this automatically via kobj_type->default_attrs.  This is the
631  * minimum data required to uniquely identify a cache.
632  */
633 static struct attribute *cache_index_default_attrs[] = {
634         &cache_type_attr.attr,
635         &cache_level_attr.attr,
636         &cache_shared_cpu_map_attr.attr,
637         NULL,
638 };
639 
640 /* Attributes which should be created if the cache device node has the
641  * right properties -- see cacheinfo_create_index_opt_attrs
642  */
643 static struct kobj_attribute *cache_index_opt_attrs[] = {
644         &cache_size_attr,
645         &cache_line_size_attr,
646         &cache_nr_sets_attr,
647         &cache_assoc_attr,
648 };
649 
650 static const struct sysfs_ops cache_index_ops = {
651         .show = cache_index_show,
652 };
653 
654 static struct kobj_type cache_index_type = {
655         .release = cache_index_release,
656         .sysfs_ops = &cache_index_ops,
657         .default_attrs = cache_index_default_attrs,
658 };
659 
660 static void cacheinfo_create_index_opt_attrs(struct cache_index_dir *dir)
661 {
662         const char *cache_name;
663         const char *cache_type;
664         struct cache *cache;
665         char *buf;
666         int i;
667 
668         buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
669         if (!buf)
670                 return;
671 
672         cache = dir->cache;
673         cache_name = cache->ofnode->full_name;
674         cache_type = cache_type_string(cache);
675 
676         /* We don't want to create an attribute that can't provide a
677          * meaningful value.  Check the return value of each optional
678          * attribute's ->show method before registering the
679          * attribute.
680          */
681         for (i = 0; i < ARRAY_SIZE(cache_index_opt_attrs); i++) {
682                 struct kobj_attribute *attr;
683                 ssize_t rc;
684 
685                 attr = cache_index_opt_attrs[i];
686 
687                 rc = attr->show(&dir->kobj, attr, buf);
688                 if (rc <= 0) {
689                         pr_debug("not creating %s attribute for "
690                                  "%s(%s) (rc = %zd)\n",
691                                  attr->attr.name, cache_name,
692                                  cache_type, rc);
693                         continue;
694                 }
695                 if (sysfs_create_file(&dir->kobj, &attr->attr))
696                         pr_debug("could not create %s attribute for %s(%s)\n",
697                                  attr->attr.name, cache_name, cache_type);
698         }
699 
700         kfree(buf);
701 }
702 
703 static void cacheinfo_create_index_dir(struct cache *cache, int index,
704                                        struct cache_dir *cache_dir)
705 {
706         struct cache_index_dir *index_dir;
707         int rc;
708 
709         index_dir = kzalloc(sizeof(*index_dir), GFP_KERNEL);
710         if (!index_dir)
711                 goto err;
712 
713         index_dir->cache = cache;
714 
715         rc = kobject_init_and_add(&index_dir->kobj, &cache_index_type,
716                                   cache_dir->kobj, "index%d", index);
717         if (rc)
718                 goto err;
719 
720         index_dir->next = cache_dir->index;
721         cache_dir->index = index_dir;
722 
723         cacheinfo_create_index_opt_attrs(index_dir);
724 
725         return;
726 err:
727         kfree(index_dir);
728 }
729 
730 static void cacheinfo_sysfs_populate(unsigned int cpu_id,
731                                      struct cache *cache_list)
732 {
733         struct cache_dir *cache_dir;
734         struct cache *cache;
735         int index = 0;
736 
737         cache_dir = cacheinfo_create_cache_dir(cpu_id);
738         if (!cache_dir)
739                 return;
740 
741         cache = cache_list;
742         while (cache) {
743                 cacheinfo_create_index_dir(cache, index, cache_dir);
744                 index++;
745                 cache = cache->next_local;
746         }
747 }
748 
749 void cacheinfo_cpu_online(unsigned int cpu_id)
750 {
751         struct cache *cache;
752 
753         cache = cache_chain_instantiate(cpu_id);
754         if (!cache)
755                 return;
756 
757         cacheinfo_sysfs_populate(cpu_id, cache);
758 }
759 
760 #ifdef CONFIG_HOTPLUG_CPU /* functions needed for cpu offline */
761 
762 static struct cache *cache_lookup_by_cpu(unsigned int cpu_id)
763 {
764         struct device_node *cpu_node;
765         struct cache *cache;
766 
767         cpu_node = of_get_cpu_node(cpu_id, NULL);
768         WARN_ONCE(!cpu_node, "no OF node found for CPU %i\n", cpu_id);
769         if (!cpu_node)
770                 return NULL;
771 
772         cache = cache_lookup_by_node(cpu_node);
773         of_node_put(cpu_node);
774 
775         return cache;
776 }
777 
778 static void remove_index_dirs(struct cache_dir *cache_dir)
779 {
780         struct cache_index_dir *index;
781 
782         index = cache_dir->index;
783 
784         while (index) {
785                 struct cache_index_dir *next;
786 
787                 next = index->next;
788                 kobject_put(&index->kobj);
789                 index = next;
790         }
791 }
792 
793 static void remove_cache_dir(struct cache_dir *cache_dir)
794 {
795         remove_index_dirs(cache_dir);
796 
797         kobject_put(cache_dir->kobj);
798 
799         kfree(cache_dir);
800 }
801 
802 static void cache_cpu_clear(struct cache *cache, int cpu)
803 {
804         while (cache) {
805                 struct cache *next = cache->next_local;
806 
807                 WARN_ONCE(!cpumask_test_cpu(cpu, &cache->shared_cpu_map),
808                           "CPU %i not accounted in %s(%s)\n",
809                           cpu, cache->ofnode->full_name,
810                           cache_type_string(cache));
811 
812                 cpumask_clear_cpu(cpu, &cache->shared_cpu_map);
813 
814                 /* Release the cache object if all the cpus using it
815                  * are offline */
816                 if (cpumask_empty(&cache->shared_cpu_map))
817                         release_cache(cache);
818 
819                 cache = next;
820         }
821 }
822 
823 void cacheinfo_cpu_offline(unsigned int cpu_id)
824 {
825         struct cache_dir *cache_dir;
826         struct cache *cache;
827 
828         /* Prevent userspace from seeing inconsistent state - remove
829          * the sysfs hierarchy first */
830         cache_dir = per_cpu(cache_dir_pcpu, cpu_id);
831 
832         /* careful, sysfs population may have failed */
833         if (cache_dir)
834                 remove_cache_dir(cache_dir);
835 
836         per_cpu(cache_dir_pcpu, cpu_id) = NULL;
837 
838         /* clear the CPU's bit in its cache chain, possibly freeing
839          * cache objects */
840         cache = cache_lookup_by_cpu(cpu_id);
841         if (cache)
842                 cache_cpu_clear(cache, cpu_id);
843 }
844 #endif /* CONFIG_HOTPLUG_CPU */
845 

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