1 // SPDX-License-Identifier: GPL-2.0
3 * cacheinfo support - processor cache information via sysfs
5 * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
6 * Author: Sudeep Holla <sudeep.holla@arm.com>
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
10 #include <linux/acpi.h>
11 #include <linux/bitops.h>
12 #include <linux/cacheinfo.h>
13 #include <linux/compiler.h>
14 #include <linux/cpu.h>
15 #include <linux/device.h>
16 #include <linux/init.h>
17 #include <linux/of_device.h>
18 #include <linux/sched.h>
19 #include <linux/slab.h>
20 #include <linux/smp.h>
21 #include <linux/sysfs.h>
23 /* pointer to per cpu cacheinfo */
24 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
25 #define ci_cacheinfo(cpu) (&per_cpu(ci_cpu_cacheinfo, cpu))
26 #define cache_leaves(cpu) (ci_cacheinfo(cpu)->num_leaves)
27 #define per_cpu_cacheinfo(cpu) (ci_cacheinfo(cpu)->info_list)
28 #define per_cpu_cacheinfo_idx(cpu, idx) \
29 (per_cpu_cacheinfo(cpu) + (idx))
31 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
33 return ci_cacheinfo(cpu);
36 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
37 struct cacheinfo *sib_leaf)
40 * For non DT/ACPI systems, assume unique level 1 caches,
41 * system-wide shared caches for all other levels. This will be used
42 * only if arch specific code has not populated shared_cpu_map
44 if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI)))
45 return !(this_leaf->level == 1);
47 if ((sib_leaf->attributes & CACHE_ID) &&
48 (this_leaf->attributes & CACHE_ID))
49 return sib_leaf->id == this_leaf->id;
51 return sib_leaf->fw_token == this_leaf->fw_token;
54 bool last_level_cache_is_valid(unsigned int cpu)
56 struct cacheinfo *llc;
58 if (!cache_leaves(cpu))
61 llc = per_cpu_cacheinfo_idx(cpu, cache_leaves(cpu) - 1);
63 return (llc->attributes & CACHE_ID) || !!llc->fw_token;
67 bool last_level_cache_is_shared(unsigned int cpu_x, unsigned int cpu_y)
69 struct cacheinfo *llc_x, *llc_y;
71 if (!last_level_cache_is_valid(cpu_x) ||
72 !last_level_cache_is_valid(cpu_y))
75 llc_x = per_cpu_cacheinfo_idx(cpu_x, cache_leaves(cpu_x) - 1);
76 llc_y = per_cpu_cacheinfo_idx(cpu_y, cache_leaves(cpu_y) - 1);
78 return cache_leaves_are_shared(llc_x, llc_y);
82 /* OF properties to query for a given cache type */
83 struct cache_type_info {
84 const char *size_prop;
85 const char *line_size_props[2];
86 const char *nr_sets_prop;
89 static const struct cache_type_info cache_type_info[] = {
91 .size_prop = "cache-size",
92 .line_size_props = { "cache-line-size",
93 "cache-block-size", },
94 .nr_sets_prop = "cache-sets",
96 .size_prop = "i-cache-size",
97 .line_size_props = { "i-cache-line-size",
98 "i-cache-block-size", },
99 .nr_sets_prop = "i-cache-sets",
101 .size_prop = "d-cache-size",
102 .line_size_props = { "d-cache-line-size",
103 "d-cache-block-size", },
104 .nr_sets_prop = "d-cache-sets",
108 static inline int get_cacheinfo_idx(enum cache_type type)
110 if (type == CACHE_TYPE_UNIFIED)
115 static void cache_size(struct cacheinfo *this_leaf, struct device_node *np)
117 const char *propname;
120 ct_idx = get_cacheinfo_idx(this_leaf->type);
121 propname = cache_type_info[ct_idx].size_prop;
123 of_property_read_u32(np, propname, &this_leaf->size);
126 /* not cache_line_size() because that's a macro in include/linux/cache.h */
127 static void cache_get_line_size(struct cacheinfo *this_leaf,
128 struct device_node *np)
132 ct_idx = get_cacheinfo_idx(this_leaf->type);
133 lim = ARRAY_SIZE(cache_type_info[ct_idx].line_size_props);
135 for (i = 0; i < lim; i++) {
138 const char *propname;
140 propname = cache_type_info[ct_idx].line_size_props[i];
141 ret = of_property_read_u32(np, propname, &line_size);
143 this_leaf->coherency_line_size = line_size;
149 static void cache_nr_sets(struct cacheinfo *this_leaf, struct device_node *np)
151 const char *propname;
154 ct_idx = get_cacheinfo_idx(this_leaf->type);
155 propname = cache_type_info[ct_idx].nr_sets_prop;
157 of_property_read_u32(np, propname, &this_leaf->number_of_sets);
160 static void cache_associativity(struct cacheinfo *this_leaf)
162 unsigned int line_size = this_leaf->coherency_line_size;
163 unsigned int nr_sets = this_leaf->number_of_sets;
164 unsigned int size = this_leaf->size;
167 * If the cache is fully associative, there is no need to
168 * check the other properties.
170 if (!(nr_sets == 1) && (nr_sets > 0 && size > 0 && line_size > 0))
171 this_leaf->ways_of_associativity = (size / nr_sets) / line_size;
174 static bool cache_node_is_unified(struct cacheinfo *this_leaf,
175 struct device_node *np)
177 return of_property_read_bool(np, "cache-unified");
180 static void cache_of_set_props(struct cacheinfo *this_leaf,
181 struct device_node *np)
184 * init_cache_level must setup the cache level correctly
185 * overriding the architecturally specified levels, so
186 * if type is NONE at this stage, it should be unified
188 if (this_leaf->type == CACHE_TYPE_NOCACHE &&
189 cache_node_is_unified(this_leaf, np))
190 this_leaf->type = CACHE_TYPE_UNIFIED;
191 cache_size(this_leaf, np);
192 cache_get_line_size(this_leaf, np);
193 cache_nr_sets(this_leaf, np);
194 cache_associativity(this_leaf);
197 static int cache_setup_of_node(unsigned int cpu)
199 struct device_node *np, *prev;
200 struct cacheinfo *this_leaf;
201 unsigned int index = 0;
203 np = of_cpu_device_node_get(cpu);
205 pr_err("Failed to find cpu%d device node\n", cpu);
211 while (index < cache_leaves(cpu)) {
212 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
213 if (this_leaf->level != 1) {
214 np = of_find_next_cache_node(np);
220 cache_of_set_props(this_leaf, np);
221 this_leaf->fw_token = np;
227 if (index != cache_leaves(cpu)) /* not all OF nodes populated */
233 static int of_count_cache_leaves(struct device_node *np)
235 unsigned int leaves = 0;
237 if (of_property_read_bool(np, "cache-size"))
239 if (of_property_read_bool(np, "i-cache-size"))
241 if (of_property_read_bool(np, "d-cache-size"))
245 /* The '[i-|d-|]cache-size' property is required, but
246 * if absent, fallback on the 'cache-unified' property.
248 if (of_property_read_bool(np, "cache-unified"))
257 int init_of_cache_level(unsigned int cpu)
259 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
260 struct device_node *np = of_cpu_device_node_get(cpu);
261 struct device_node *prev = NULL;
262 unsigned int levels = 0, leaves, level;
264 leaves = of_count_cache_leaves(np);
269 while ((np = of_find_next_cache_node(np))) {
272 if (!of_device_is_compatible(np, "cache"))
274 if (of_property_read_u32(np, "cache-level", &level))
279 leaves += of_count_cache_leaves(np);
284 this_cpu_ci->num_levels = levels;
285 this_cpu_ci->num_leaves = leaves;
295 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
296 int init_of_cache_level(unsigned int cpu) { return 0; }
299 int __weak cache_setup_acpi(unsigned int cpu)
304 unsigned int coherency_max_size;
306 static int cache_setup_properties(unsigned int cpu)
310 if (of_have_populated_dt())
311 ret = cache_setup_of_node(cpu);
312 else if (!acpi_disabled)
313 ret = cache_setup_acpi(cpu);
318 static int cache_shared_cpu_map_setup(unsigned int cpu)
320 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
321 struct cacheinfo *this_leaf, *sib_leaf;
322 unsigned int index, sib_index;
325 if (this_cpu_ci->cpu_map_populated)
329 * skip setting up cache properties if LLC is valid, just need
330 * to update the shared cpu_map if the cache attributes were
331 * populated early before all the cpus are brought online
333 if (!last_level_cache_is_valid(cpu)) {
334 ret = cache_setup_properties(cpu);
339 for (index = 0; index < cache_leaves(cpu); index++) {
342 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
344 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
345 for_each_online_cpu(i) {
346 struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
348 if (i == cpu || !sib_cpu_ci->info_list)
349 continue;/* skip if itself or no cacheinfo */
350 for (sib_index = 0; sib_index < cache_leaves(i); sib_index++) {
351 sib_leaf = per_cpu_cacheinfo_idx(i, sib_index);
352 if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
353 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
354 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
359 /* record the maximum cache line size */
360 if (this_leaf->coherency_line_size > coherency_max_size)
361 coherency_max_size = this_leaf->coherency_line_size;
367 static void cache_shared_cpu_map_remove(unsigned int cpu)
369 struct cacheinfo *this_leaf, *sib_leaf;
370 unsigned int sibling, index, sib_index;
372 for (index = 0; index < cache_leaves(cpu); index++) {
373 this_leaf = per_cpu_cacheinfo_idx(cpu, index);
374 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
375 struct cpu_cacheinfo *sib_cpu_ci =
376 get_cpu_cacheinfo(sibling);
378 if (sibling == cpu || !sib_cpu_ci->info_list)
379 continue;/* skip if itself or no cacheinfo */
381 for (sib_index = 0; sib_index < cache_leaves(sibling); sib_index++) {
382 sib_leaf = per_cpu_cacheinfo_idx(sibling, sib_index);
383 if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
384 cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
385 cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
393 static void free_cache_attributes(unsigned int cpu)
395 if (!per_cpu_cacheinfo(cpu))
398 cache_shared_cpu_map_remove(cpu);
401 int __weak init_cache_level(unsigned int cpu)
406 int __weak populate_cache_leaves(unsigned int cpu)
412 int allocate_cache_info(int cpu)
414 per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
415 sizeof(struct cacheinfo), GFP_ATOMIC);
416 if (!per_cpu_cacheinfo(cpu)) {
417 cache_leaves(cpu) = 0;
424 int fetch_cache_info(unsigned int cpu)
426 struct cpu_cacheinfo *this_cpu_ci;
427 unsigned int levels = 0, split_levels = 0;
431 ret = init_of_cache_level(cpu);
435 ret = acpi_get_cache_info(cpu, &levels, &split_levels);
439 this_cpu_ci = get_cpu_cacheinfo(cpu);
440 this_cpu_ci->num_levels = levels;
443 * - there cannot be any split caches (data/instruction)
444 * above a unified cache
445 * - data/instruction caches come by pair
447 this_cpu_ci->num_leaves = levels + split_levels;
449 if (!cache_leaves(cpu))
452 return allocate_cache_info(cpu);
455 int detect_cache_attributes(unsigned int cpu)
459 /* Since early initialization/allocation of the cacheinfo is allowed
460 * via fetch_cache_info() and this also gets called as CPU hotplug
461 * callbacks via cacheinfo_cpu_online, the init/alloc can be skipped
462 * as it will happen only once (the cacheinfo memory is never freed).
463 * Just populate the cacheinfo.
465 if (per_cpu_cacheinfo(cpu))
466 goto populate_leaves;
468 if (init_cache_level(cpu) || !cache_leaves(cpu))
471 ret = allocate_cache_info(cpu);
477 * If LLC is valid the cache leaves were already populated so just go to
478 * update the cpu map.
480 if (!last_level_cache_is_valid(cpu)) {
482 * populate_cache_leaves() may completely setup the cache leaves and
483 * shared_cpu_map or it may leave it partially setup.
485 ret = populate_cache_leaves(cpu);
491 * For systems using DT for cache hierarchy, fw_token
492 * and shared_cpu_map will be set up here only if they are
493 * not populated already
495 ret = cache_shared_cpu_map_setup(cpu);
497 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
504 free_cache_attributes(cpu);
508 /* pointer to cpuX/cache device */
509 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
510 #define per_cpu_cache_dev(cpu) (per_cpu(ci_cache_dev, cpu))
512 static cpumask_t cache_dev_map;
514 /* pointer to array of devices for cpuX/cache/indexY */
515 static DEFINE_PER_CPU(struct device **, ci_index_dev);
516 #define per_cpu_index_dev(cpu) (per_cpu(ci_index_dev, cpu))
517 #define per_cache_index_dev(cpu, idx) ((per_cpu_index_dev(cpu))[idx])
519 #define show_one(file_name, object) \
520 static ssize_t file_name##_show(struct device *dev, \
521 struct device_attribute *attr, char *buf) \
523 struct cacheinfo *this_leaf = dev_get_drvdata(dev); \
524 return sysfs_emit(buf, "%u\n", this_leaf->object); \
528 show_one(level, level);
529 show_one(coherency_line_size, coherency_line_size);
530 show_one(number_of_sets, number_of_sets);
531 show_one(physical_line_partition, physical_line_partition);
532 show_one(ways_of_associativity, ways_of_associativity);
534 static ssize_t size_show(struct device *dev,
535 struct device_attribute *attr, char *buf)
537 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
539 return sysfs_emit(buf, "%uK\n", this_leaf->size >> 10);
542 static ssize_t shared_cpu_map_show(struct device *dev,
543 struct device_attribute *attr, char *buf)
545 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
546 const struct cpumask *mask = &this_leaf->shared_cpu_map;
548 return sysfs_emit(buf, "%*pb\n", nr_cpu_ids, mask);
551 static ssize_t shared_cpu_list_show(struct device *dev,
552 struct device_attribute *attr, char *buf)
554 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
555 const struct cpumask *mask = &this_leaf->shared_cpu_map;
557 return sysfs_emit(buf, "%*pbl\n", nr_cpu_ids, mask);
560 static ssize_t type_show(struct device *dev,
561 struct device_attribute *attr, char *buf)
563 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
566 switch (this_leaf->type) {
567 case CACHE_TYPE_DATA:
570 case CACHE_TYPE_INST:
571 output = "Instruction";
573 case CACHE_TYPE_UNIFIED:
580 return sysfs_emit(buf, "%s\n", output);
583 static ssize_t allocation_policy_show(struct device *dev,
584 struct device_attribute *attr, char *buf)
586 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
587 unsigned int ci_attr = this_leaf->attributes;
590 if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
591 output = "ReadWriteAllocate";
592 else if (ci_attr & CACHE_READ_ALLOCATE)
593 output = "ReadAllocate";
594 else if (ci_attr & CACHE_WRITE_ALLOCATE)
595 output = "WriteAllocate";
599 return sysfs_emit(buf, "%s\n", output);
602 static ssize_t write_policy_show(struct device *dev,
603 struct device_attribute *attr, char *buf)
605 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
606 unsigned int ci_attr = this_leaf->attributes;
609 if (ci_attr & CACHE_WRITE_THROUGH)
610 n = sysfs_emit(buf, "WriteThrough\n");
611 else if (ci_attr & CACHE_WRITE_BACK)
612 n = sysfs_emit(buf, "WriteBack\n");
616 static DEVICE_ATTR_RO(id);
617 static DEVICE_ATTR_RO(level);
618 static DEVICE_ATTR_RO(type);
619 static DEVICE_ATTR_RO(coherency_line_size);
620 static DEVICE_ATTR_RO(ways_of_associativity);
621 static DEVICE_ATTR_RO(number_of_sets);
622 static DEVICE_ATTR_RO(size);
623 static DEVICE_ATTR_RO(allocation_policy);
624 static DEVICE_ATTR_RO(write_policy);
625 static DEVICE_ATTR_RO(shared_cpu_map);
626 static DEVICE_ATTR_RO(shared_cpu_list);
627 static DEVICE_ATTR_RO(physical_line_partition);
629 static struct attribute *cache_default_attrs[] = {
632 &dev_attr_level.attr,
633 &dev_attr_shared_cpu_map.attr,
634 &dev_attr_shared_cpu_list.attr,
635 &dev_attr_coherency_line_size.attr,
636 &dev_attr_ways_of_associativity.attr,
637 &dev_attr_number_of_sets.attr,
639 &dev_attr_allocation_policy.attr,
640 &dev_attr_write_policy.attr,
641 &dev_attr_physical_line_partition.attr,
646 cache_default_attrs_is_visible(struct kobject *kobj,
647 struct attribute *attr, int unused)
649 struct device *dev = kobj_to_dev(kobj);
650 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
651 const struct cpumask *mask = &this_leaf->shared_cpu_map;
652 umode_t mode = attr->mode;
654 if ((attr == &dev_attr_id.attr) && (this_leaf->attributes & CACHE_ID))
656 if ((attr == &dev_attr_type.attr) && this_leaf->type)
658 if ((attr == &dev_attr_level.attr) && this_leaf->level)
660 if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
662 if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
664 if ((attr == &dev_attr_coherency_line_size.attr) &&
665 this_leaf->coherency_line_size)
667 if ((attr == &dev_attr_ways_of_associativity.attr) &&
668 this_leaf->size) /* allow 0 = full associativity */
670 if ((attr == &dev_attr_number_of_sets.attr) &&
671 this_leaf->number_of_sets)
673 if ((attr == &dev_attr_size.attr) && this_leaf->size)
675 if ((attr == &dev_attr_write_policy.attr) &&
676 (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
678 if ((attr == &dev_attr_allocation_policy.attr) &&
679 (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
681 if ((attr == &dev_attr_physical_line_partition.attr) &&
682 this_leaf->physical_line_partition)
688 static const struct attribute_group cache_default_group = {
689 .attrs = cache_default_attrs,
690 .is_visible = cache_default_attrs_is_visible,
693 static const struct attribute_group *cache_default_groups[] = {
694 &cache_default_group,
698 static const struct attribute_group *cache_private_groups[] = {
699 &cache_default_group,
700 NULL, /* Place holder for private group */
704 const struct attribute_group *
705 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
710 static const struct attribute_group **
711 cache_get_attribute_groups(struct cacheinfo *this_leaf)
713 const struct attribute_group *priv_group =
714 cache_get_priv_group(this_leaf);
717 return cache_default_groups;
719 if (!cache_private_groups[1])
720 cache_private_groups[1] = priv_group;
722 return cache_private_groups;
725 /* Add/Remove cache interface for CPU device */
726 static void cpu_cache_sysfs_exit(unsigned int cpu)
729 struct device *ci_dev;
731 if (per_cpu_index_dev(cpu)) {
732 for (i = 0; i < cache_leaves(cpu); i++) {
733 ci_dev = per_cache_index_dev(cpu, i);
736 device_unregister(ci_dev);
738 kfree(per_cpu_index_dev(cpu));
739 per_cpu_index_dev(cpu) = NULL;
741 device_unregister(per_cpu_cache_dev(cpu));
742 per_cpu_cache_dev(cpu) = NULL;
745 static int cpu_cache_sysfs_init(unsigned int cpu)
747 struct device *dev = get_cpu_device(cpu);
749 if (per_cpu_cacheinfo(cpu) == NULL)
752 per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
753 if (IS_ERR(per_cpu_cache_dev(cpu)))
754 return PTR_ERR(per_cpu_cache_dev(cpu));
756 /* Allocate all required memory */
757 per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
758 sizeof(struct device *), GFP_KERNEL);
759 if (unlikely(per_cpu_index_dev(cpu) == NULL))
765 cpu_cache_sysfs_exit(cpu);
769 static int cache_add_dev(unsigned int cpu)
773 struct device *ci_dev, *parent;
774 struct cacheinfo *this_leaf;
775 const struct attribute_group **cache_groups;
777 rc = cpu_cache_sysfs_init(cpu);
778 if (unlikely(rc < 0))
781 parent = per_cpu_cache_dev(cpu);
782 for (i = 0; i < cache_leaves(cpu); i++) {
783 this_leaf = per_cpu_cacheinfo_idx(cpu, i);
784 if (this_leaf->disable_sysfs)
786 if (this_leaf->type == CACHE_TYPE_NOCACHE)
788 cache_groups = cache_get_attribute_groups(this_leaf);
789 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
791 if (IS_ERR(ci_dev)) {
792 rc = PTR_ERR(ci_dev);
795 per_cache_index_dev(cpu, i) = ci_dev;
797 cpumask_set_cpu(cpu, &cache_dev_map);
801 cpu_cache_sysfs_exit(cpu);
805 static int cacheinfo_cpu_online(unsigned int cpu)
807 int rc = detect_cache_attributes(cpu);
811 rc = cache_add_dev(cpu);
813 free_cache_attributes(cpu);
817 static int cacheinfo_cpu_pre_down(unsigned int cpu)
819 if (cpumask_test_and_clear_cpu(cpu, &cache_dev_map))
820 cpu_cache_sysfs_exit(cpu);
822 free_cache_attributes(cpu);
826 static int __init cacheinfo_sysfs_init(void)
828 return cpuhp_setup_state(CPUHP_AP_BASE_CACHEINFO_ONLINE,
829 "base/cacheinfo:online",
830 cacheinfo_cpu_online, cacheinfo_cpu_pre_down);
832 device_initcall(cacheinfo_sysfs_init);