2 * Processor cache information made available to userspace via sysfs;
3 * intended to be compatible with x86 intel_cacheinfo implementation.
5 * Copyright 2008 IBM Corporation
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.
13 #include <linux/cpu.h>
14 #include <linux/cpumask.h>
15 #include <linux/kernel.h>
16 #include <linux/kobject.h>
17 #include <linux/list.h>
18 #include <linux/notifier.h>
20 #include <linux/percpu.h>
21 #include <linux/slab.h>
24 #include "cacheinfo.h"
26 /* per-cpu object for tracking:
27 * - a "cache" kobject for the top-level directory
28 * - a list of "index" objects representing the cpu's local cache hierarchy
31 struct kobject *kobj; /* bare (not embedded) kobject for cache
33 struct cache_index_dir *index; /* list of index objects */
36 /* "index" object: each cpu's cache directory has an index
37 * subdirectory corresponding to a cache object associated with the
38 * cpu. This object's lifetime is managed via the embedded kobject.
40 struct cache_index_dir {
42 struct cache_index_dir *next; /* next index in parent directory */
46 /* Template for determining which OF properties to query for a given
48 struct cache_type_info {
50 const char *size_prop;
52 /* Allow for both [di]-cache-line-size and
53 * [di]-cache-block-size properties. According to the PowerPC
54 * Processor binding, -line-size should be provided if it
55 * differs from the cache block size (that which is operated
56 * on by cache instructions), so we look for -line-size first.
57 * See cache_get_line_size(). */
59 const char *line_size_props[2];
60 const char *nr_sets_prop;
63 /* These are used to index the cache_type_info array. */
64 #define CACHE_TYPE_UNIFIED 0
65 #define CACHE_TYPE_INSTRUCTION 1
66 #define CACHE_TYPE_DATA 2
68 static const struct cache_type_info cache_type_info[] = {
70 /* PowerPC Processor binding says the [di]-cache-*
71 * must be equal on unified caches, so just use
72 * d-cache properties. */
74 .size_prop = "d-cache-size",
75 .line_size_props = { "d-cache-line-size",
76 "d-cache-block-size", },
77 .nr_sets_prop = "d-cache-sets",
80 .name = "Instruction",
81 .size_prop = "i-cache-size",
82 .line_size_props = { "i-cache-line-size",
83 "i-cache-block-size", },
84 .nr_sets_prop = "i-cache-sets",
88 .size_prop = "d-cache-size",
89 .line_size_props = { "d-cache-line-size",
90 "d-cache-block-size", },
91 .nr_sets_prop = "d-cache-sets",
95 /* Cache object: each instance of this corresponds to a distinct cache
96 * in the system. There are separate objects for Harvard caches: one
97 * each for instruction and data, and each refers to the same OF node.
98 * The refcount of the OF node is elevated for the lifetime of the
99 * cache object. A cache object is released when its shared_cpu_map
100 * is cleared (see cache_cpu_clear).
102 * A cache object is on two lists: an unsorted global list
103 * (cache_list) of cache objects; and a singly-linked list
104 * representing the local cache hierarchy, which is ordered by level
105 * (e.g. L1d -> L1i -> L2 -> L3).
108 struct device_node *ofnode; /* OF node for this cache, may be cpu */
109 struct cpumask shared_cpu_map; /* online CPUs using this cache */
110 int type; /* split cache disambiguation */
111 int level; /* level not explicit in device tree */
112 struct list_head list; /* global list of cache objects */
113 struct cache *next_local; /* next cache of >= level */
116 static DEFINE_PER_CPU(struct cache_dir *, cache_dir_pcpu);
118 /* traversal/modification of this list occurs only at cpu hotplug time;
119 * access is serialized by cpu hotplug locking
121 static LIST_HEAD(cache_list);
123 static struct cache_index_dir *kobj_to_cache_index_dir(struct kobject *k)
125 return container_of(k, struct cache_index_dir, kobj);
128 static const char *cache_type_string(const struct cache *cache)
130 return cache_type_info[cache->type].name;
133 static void cache_init(struct cache *cache, int type, int level,
134 struct device_node *ofnode)
137 cache->level = level;
138 cache->ofnode = of_node_get(ofnode);
139 INIT_LIST_HEAD(&cache->list);
140 list_add(&cache->list, &cache_list);
143 static struct cache *new_cache(int type, int level, struct device_node *ofnode)
147 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
149 cache_init(cache, type, level, ofnode);
154 static void release_cache_debugcheck(struct cache *cache)
158 list_for_each_entry(iter, &cache_list, list)
159 WARN_ONCE(iter->next_local == cache,
160 "cache for %s(%s) refers to cache for %s(%s)\n",
161 iter->ofnode->full_name,
162 cache_type_string(iter),
163 cache->ofnode->full_name,
164 cache_type_string(cache));
167 static void release_cache(struct cache *cache)
172 pr_debug("freeing L%d %s cache for %s\n", cache->level,
173 cache_type_string(cache), cache->ofnode->full_name);
175 release_cache_debugcheck(cache);
176 list_del(&cache->list);
177 of_node_put(cache->ofnode);
181 static void cache_cpu_set(struct cache *cache, int cpu)
183 struct cache *next = cache;
186 WARN_ONCE(cpumask_test_cpu(cpu, &next->shared_cpu_map),
187 "CPU %i already accounted in %s(%s)\n",
188 cpu, next->ofnode->full_name,
189 cache_type_string(next));
190 cpumask_set_cpu(cpu, &next->shared_cpu_map);
191 next = next->next_local;
195 static int cache_size(const struct cache *cache, unsigned int *ret)
197 const char *propname;
198 const __be32 *cache_size;
200 propname = cache_type_info[cache->type].size_prop;
202 cache_size = of_get_property(cache->ofnode, propname, NULL);
206 *ret = of_read_number(cache_size, 1);
210 static int cache_size_kb(const struct cache *cache, unsigned int *ret)
214 if (cache_size(cache, &size))
221 /* not cache_line_size() because that's a macro in include/linux/cache.h */
222 static int cache_get_line_size(const struct cache *cache, unsigned int *ret)
224 const __be32 *line_size;
227 lim = ARRAY_SIZE(cache_type_info[cache->type].line_size_props);
229 for (i = 0; i < lim; i++) {
230 const char *propname;
232 propname = cache_type_info[cache->type].line_size_props[i];
233 line_size = of_get_property(cache->ofnode, propname, NULL);
241 *ret = of_read_number(line_size, 1);
245 static int cache_nr_sets(const struct cache *cache, unsigned int *ret)
247 const char *propname;
248 const __be32 *nr_sets;
250 propname = cache_type_info[cache->type].nr_sets_prop;
252 nr_sets = of_get_property(cache->ofnode, propname, NULL);
256 *ret = of_read_number(nr_sets, 1);
260 static int cache_associativity(const struct cache *cache, unsigned int *ret)
262 unsigned int line_size;
263 unsigned int nr_sets;
266 if (cache_nr_sets(cache, &nr_sets))
269 /* If the cache is fully associative, there is no need to
270 * check the other properties.
277 if (cache_get_line_size(cache, &line_size))
279 if (cache_size(cache, &size))
282 if (!(nr_sets > 0 && size > 0 && line_size > 0))
285 *ret = (size / nr_sets) / line_size;
291 /* helper for dealing with split caches */
292 static struct cache *cache_find_first_sibling(struct cache *cache)
296 if (cache->type == CACHE_TYPE_UNIFIED)
299 list_for_each_entry(iter, &cache_list, list)
300 if (iter->ofnode == cache->ofnode && iter->next_local == cache)
306 /* return the first cache on a local list matching node */
307 static struct cache *cache_lookup_by_node(const struct device_node *node)
309 struct cache *cache = NULL;
312 list_for_each_entry(iter, &cache_list, list) {
313 if (iter->ofnode != node)
315 cache = cache_find_first_sibling(iter);
322 static bool cache_node_is_unified(const struct device_node *np)
324 return of_get_property(np, "cache-unified", NULL);
327 static struct cache *cache_do_one_devnode_unified(struct device_node *node,
332 pr_debug("creating L%d ucache for %s\n", level, node->full_name);
334 cache = new_cache(CACHE_TYPE_UNIFIED, level, node);
339 static struct cache *cache_do_one_devnode_split(struct device_node *node,
342 struct cache *dcache, *icache;
344 pr_debug("creating L%d dcache and icache for %s\n", level,
347 dcache = new_cache(CACHE_TYPE_DATA, level, node);
348 icache = new_cache(CACHE_TYPE_INSTRUCTION, level, node);
350 if (!dcache || !icache)
353 dcache->next_local = icache;
357 release_cache(dcache);
358 release_cache(icache);
362 static struct cache *cache_do_one_devnode(struct device_node *node, int level)
366 if (cache_node_is_unified(node))
367 cache = cache_do_one_devnode_unified(node, level);
369 cache = cache_do_one_devnode_split(node, level);
374 static struct cache *cache_lookup_or_instantiate(struct device_node *node,
379 cache = cache_lookup_by_node(node);
381 WARN_ONCE(cache && cache->level != level,
382 "cache level mismatch on lookup (got %d, expected %d)\n",
383 cache->level, level);
386 cache = cache_do_one_devnode(node, level);
391 static void link_cache_lists(struct cache *smaller, struct cache *bigger)
393 while (smaller->next_local) {
394 if (smaller->next_local == bigger)
395 return; /* already linked */
396 smaller = smaller->next_local;
399 smaller->next_local = bigger;
402 static void do_subsidiary_caches_debugcheck(struct cache *cache)
404 WARN_ON_ONCE(cache->level != 1);
405 WARN_ON_ONCE(strcmp(cache->ofnode->type, "cpu"));
408 static void do_subsidiary_caches(struct cache *cache)
410 struct device_node *subcache_node;
411 int level = cache->level;
413 do_subsidiary_caches_debugcheck(cache);
415 while ((subcache_node = of_find_next_cache_node(cache->ofnode))) {
416 struct cache *subcache;
419 subcache = cache_lookup_or_instantiate(subcache_node, level);
420 of_node_put(subcache_node);
424 link_cache_lists(cache, subcache);
429 static struct cache *cache_chain_instantiate(unsigned int cpu_id)
431 struct device_node *cpu_node;
432 struct cache *cpu_cache = NULL;
434 pr_debug("creating cache object(s) for CPU %i\n", cpu_id);
436 cpu_node = of_get_cpu_node(cpu_id, NULL);
437 WARN_ONCE(!cpu_node, "no OF node found for CPU %i\n", cpu_id);
441 cpu_cache = cache_lookup_or_instantiate(cpu_node, 1);
445 do_subsidiary_caches(cpu_cache);
447 cache_cpu_set(cpu_cache, cpu_id);
449 of_node_put(cpu_node);
454 static struct cache_dir *cacheinfo_create_cache_dir(unsigned int cpu_id)
456 struct cache_dir *cache_dir;
458 struct kobject *kobj = NULL;
460 dev = get_cpu_device(cpu_id);
461 WARN_ONCE(!dev, "no dev for CPU %i\n", cpu_id);
465 kobj = kobject_create_and_add("cache", &dev->kobj);
469 cache_dir = kzalloc(sizeof(*cache_dir), GFP_KERNEL);
473 cache_dir->kobj = kobj;
475 WARN_ON_ONCE(per_cpu(cache_dir_pcpu, cpu_id) != NULL);
477 per_cpu(cache_dir_pcpu, cpu_id) = cache_dir;
485 static void cache_index_release(struct kobject *kobj)
487 struct cache_index_dir *index;
489 index = kobj_to_cache_index_dir(kobj);
491 pr_debug("freeing index directory for L%d %s cache\n",
492 index->cache->level, cache_type_string(index->cache));
497 static ssize_t cache_index_show(struct kobject *k, struct attribute *attr, char *buf)
499 struct kobj_attribute *kobj_attr;
501 kobj_attr = container_of(attr, struct kobj_attribute, attr);
503 return kobj_attr->show(k, kobj_attr, buf);
506 static struct cache *index_kobj_to_cache(struct kobject *k)
508 struct cache_index_dir *index;
510 index = kobj_to_cache_index_dir(k);
515 static ssize_t size_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
517 unsigned int size_kb;
520 cache = index_kobj_to_cache(k);
522 if (cache_size_kb(cache, &size_kb))
525 return sprintf(buf, "%uK\n", size_kb);
528 static struct kobj_attribute cache_size_attr =
529 __ATTR(size, 0444, size_show, NULL);
532 static ssize_t line_size_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
534 unsigned int line_size;
537 cache = index_kobj_to_cache(k);
539 if (cache_get_line_size(cache, &line_size))
542 return sprintf(buf, "%u\n", line_size);
545 static struct kobj_attribute cache_line_size_attr =
546 __ATTR(coherency_line_size, 0444, line_size_show, NULL);
548 static ssize_t nr_sets_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
550 unsigned int nr_sets;
553 cache = index_kobj_to_cache(k);
555 if (cache_nr_sets(cache, &nr_sets))
558 return sprintf(buf, "%u\n", nr_sets);
561 static struct kobj_attribute cache_nr_sets_attr =
562 __ATTR(number_of_sets, 0444, nr_sets_show, NULL);
564 static ssize_t associativity_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
566 unsigned int associativity;
569 cache = index_kobj_to_cache(k);
571 if (cache_associativity(cache, &associativity))
574 return sprintf(buf, "%u\n", associativity);
577 static struct kobj_attribute cache_assoc_attr =
578 __ATTR(ways_of_associativity, 0444, associativity_show, NULL);
580 static ssize_t type_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
584 cache = index_kobj_to_cache(k);
586 return sprintf(buf, "%s\n", cache_type_string(cache));
589 static struct kobj_attribute cache_type_attr =
590 __ATTR(type, 0444, type_show, NULL);
592 static ssize_t level_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
594 struct cache_index_dir *index;
597 index = kobj_to_cache_index_dir(k);
598 cache = index->cache;
600 return sprintf(buf, "%d\n", cache->level);
603 static struct kobj_attribute cache_level_attr =
604 __ATTR(level, 0444, level_show, NULL);
606 static ssize_t shared_cpu_map_show(struct kobject *k, struct kobj_attribute *attr, char *buf)
608 struct cache_index_dir *index;
613 index = kobj_to_cache_index_dir(k);
614 cache = index->cache;
618 n = cpumask_scnprintf(buf, len, &cache->shared_cpu_map);
625 static struct kobj_attribute cache_shared_cpu_map_attr =
626 __ATTR(shared_cpu_map, 0444, shared_cpu_map_show, NULL);
628 /* Attributes which should always be created -- the kobject/sysfs core
629 * does this automatically via kobj_type->default_attrs. This is the
630 * minimum data required to uniquely identify a cache.
632 static struct attribute *cache_index_default_attrs[] = {
633 &cache_type_attr.attr,
634 &cache_level_attr.attr,
635 &cache_shared_cpu_map_attr.attr,
639 /* Attributes which should be created if the cache device node has the
640 * right properties -- see cacheinfo_create_index_opt_attrs
642 static struct kobj_attribute *cache_index_opt_attrs[] = {
644 &cache_line_size_attr,
649 static const struct sysfs_ops cache_index_ops = {
650 .show = cache_index_show,
653 static struct kobj_type cache_index_type = {
654 .release = cache_index_release,
655 .sysfs_ops = &cache_index_ops,
656 .default_attrs = cache_index_default_attrs,
659 static void cacheinfo_create_index_opt_attrs(struct cache_index_dir *dir)
661 const char *cache_name;
662 const char *cache_type;
667 buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
672 cache_name = cache->ofnode->full_name;
673 cache_type = cache_type_string(cache);
675 /* We don't want to create an attribute that can't provide a
676 * meaningful value. Check the return value of each optional
677 * attribute's ->show method before registering the
680 for (i = 0; i < ARRAY_SIZE(cache_index_opt_attrs); i++) {
681 struct kobj_attribute *attr;
684 attr = cache_index_opt_attrs[i];
686 rc = attr->show(&dir->kobj, attr, buf);
688 pr_debug("not creating %s attribute for "
689 "%s(%s) (rc = %zd)\n",
690 attr->attr.name, cache_name,
694 if (sysfs_create_file(&dir->kobj, &attr->attr))
695 pr_debug("could not create %s attribute for %s(%s)\n",
696 attr->attr.name, cache_name, cache_type);
702 static void cacheinfo_create_index_dir(struct cache *cache, int index,
703 struct cache_dir *cache_dir)
705 struct cache_index_dir *index_dir;
708 index_dir = kzalloc(sizeof(*index_dir), GFP_KERNEL);
712 index_dir->cache = cache;
714 rc = kobject_init_and_add(&index_dir->kobj, &cache_index_type,
715 cache_dir->kobj, "index%d", index);
719 index_dir->next = cache_dir->index;
720 cache_dir->index = index_dir;
722 cacheinfo_create_index_opt_attrs(index_dir);
729 static void cacheinfo_sysfs_populate(unsigned int cpu_id,
730 struct cache *cache_list)
732 struct cache_dir *cache_dir;
736 cache_dir = cacheinfo_create_cache_dir(cpu_id);
742 cacheinfo_create_index_dir(cache, index, cache_dir);
744 cache = cache->next_local;
748 void cacheinfo_cpu_online(unsigned int cpu_id)
752 cache = cache_chain_instantiate(cpu_id);
756 cacheinfo_sysfs_populate(cpu_id, cache);
759 /* functions needed to remove cache entry for cpu offline or suspend/resume */
761 #if (defined(CONFIG_PPC_PSERIES) && defined(CONFIG_SUSPEND)) || \
762 defined(CONFIG_HOTPLUG_CPU)
764 static struct cache *cache_lookup_by_cpu(unsigned int cpu_id)
766 struct device_node *cpu_node;
769 cpu_node = of_get_cpu_node(cpu_id, NULL);
770 WARN_ONCE(!cpu_node, "no OF node found for CPU %i\n", cpu_id);
774 cache = cache_lookup_by_node(cpu_node);
775 of_node_put(cpu_node);
780 static void remove_index_dirs(struct cache_dir *cache_dir)
782 struct cache_index_dir *index;
784 index = cache_dir->index;
787 struct cache_index_dir *next;
790 kobject_put(&index->kobj);
795 static void remove_cache_dir(struct cache_dir *cache_dir)
797 remove_index_dirs(cache_dir);
799 /* Remove cache dir from sysfs */
800 kobject_del(cache_dir->kobj);
802 kobject_put(cache_dir->kobj);
807 static void cache_cpu_clear(struct cache *cache, int cpu)
810 struct cache *next = cache->next_local;
812 WARN_ONCE(!cpumask_test_cpu(cpu, &cache->shared_cpu_map),
813 "CPU %i not accounted in %s(%s)\n",
814 cpu, cache->ofnode->full_name,
815 cache_type_string(cache));
817 cpumask_clear_cpu(cpu, &cache->shared_cpu_map);
819 /* Release the cache object if all the cpus using it
821 if (cpumask_empty(&cache->shared_cpu_map))
822 release_cache(cache);
828 void cacheinfo_cpu_offline(unsigned int cpu_id)
830 struct cache_dir *cache_dir;
833 /* Prevent userspace from seeing inconsistent state - remove
834 * the sysfs hierarchy first */
835 cache_dir = per_cpu(cache_dir_pcpu, cpu_id);
837 /* careful, sysfs population may have failed */
839 remove_cache_dir(cache_dir);
841 per_cpu(cache_dir_pcpu, cpu_id) = NULL;
843 /* clear the CPU's bit in its cache chain, possibly freeing
845 cache = cache_lookup_by_cpu(cpu_id);
847 cache_cpu_clear(cache, cpu_id);
849 #endif /* (CONFIG_PPC_PSERIES && CONFIG_SUSPEND) || CONFIG_HOTPLUG_CPU */