1 /*
2 * cacheinfo support - processor cache information via sysfs
3 *
4 * Based on arch/x86/kernel/cpu/intel_cacheinfo.c
5 * Author: Sudeep Holla <sudeep.holla@arm.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
12 * kind, whether express or implied; without even the implied warranty
13 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19 #include <linux/acpi.h>
20 #include <linux/bitops.h>
21 #include <linux/cacheinfo.h>
22 #include <linux/compiler.h>
23 #include <linux/cpu.h>
24 #include <linux/device.h>
25 #include <linux/init.h>
26 #include <linux/of.h>
27 #include <linux/sched.h>
28 #include <linux/slab.h>
29 #include <linux/smp.h>
30 #include <linux/sysfs.h>
31
32 /* pointer to per cpu cacheinfo */
33 static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
34 #define ci_cacheinfo(cpu) (&per_cpu(ci_cpu_cacheinfo, cpu))
35 #define cache_leaves(cpu) (ci_cacheinfo(cpu)->num_leaves)
36 #define per_cpu_cacheinfo(cpu) (ci_cacheinfo(cpu)->info_list)
37
get_cpu_cacheinfo(unsigned int cpu)38 struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu)
39 {
40 return ci_cacheinfo(cpu);
41 }
42
43 #ifdef CONFIG_OF
cache_setup_of_node(unsigned int cpu)44 static int cache_setup_of_node(unsigned int cpu)
45 {
46 struct device_node *np;
47 struct cacheinfo *this_leaf;
48 struct device *cpu_dev = get_cpu_device(cpu);
49 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
50 unsigned int index = 0;
51
52 /* skip if of_node is already populated */
53 if (this_cpu_ci->info_list->of_node)
54 return 0;
55
56 if (!cpu_dev) {
57 pr_err("No cpu device for CPU %d\n", cpu);
58 return -ENODEV;
59 }
60 np = cpu_dev->of_node;
61 if (!np) {
62 pr_err("Failed to find cpu%d device node\n", cpu);
63 return -ENOENT;
64 }
65
66 while (index < cache_leaves(cpu)) {
67 this_leaf = this_cpu_ci->info_list + index;
68 if (this_leaf->level != 1)
69 np = of_find_next_cache_node(np);
70 else
71 np = of_node_get(np);/* cpu node itself */
72 if (!np)
73 break;
74 this_leaf->of_node = np;
75 index++;
76 }
77
78 if (index != cache_leaves(cpu)) /* not all OF nodes populated */
79 return -ENOENT;
80
81 return 0;
82 }
83
cache_leaves_are_shared(struct cacheinfo * this_leaf,struct cacheinfo * sib_leaf)84 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
85 struct cacheinfo *sib_leaf)
86 {
87 return sib_leaf->of_node == this_leaf->of_node;
88 }
89 #else
cache_setup_of_node(unsigned int cpu)90 static inline int cache_setup_of_node(unsigned int cpu) { return 0; }
cache_leaves_are_shared(struct cacheinfo * this_leaf,struct cacheinfo * sib_leaf)91 static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
92 struct cacheinfo *sib_leaf)
93 {
94 /*
95 * For non-DT systems, assume unique level 1 cache, system-wide
96 * shared caches for all other levels. This will be used only if
97 * arch specific code has not populated shared_cpu_map
98 */
99 return !(this_leaf->level == 1);
100 }
101 #endif
102
cache_shared_cpu_map_setup(unsigned int cpu)103 static int cache_shared_cpu_map_setup(unsigned int cpu)
104 {
105 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
106 struct cacheinfo *this_leaf, *sib_leaf;
107 unsigned int index;
108 int ret = 0;
109
110 if (this_cpu_ci->cpu_map_populated)
111 return 0;
112
113 if (of_have_populated_dt())
114 ret = cache_setup_of_node(cpu);
115 else if (!acpi_disabled)
116 /* No cache property/hierarchy support yet in ACPI */
117 ret = -ENOTSUPP;
118 if (ret)
119 return ret;
120
121 for (index = 0; index < cache_leaves(cpu); index++) {
122 unsigned int i;
123
124 this_leaf = this_cpu_ci->info_list + index;
125 /* skip if shared_cpu_map is already populated */
126 if (!cpumask_empty(&this_leaf->shared_cpu_map))
127 continue;
128
129 cpumask_set_cpu(cpu, &this_leaf->shared_cpu_map);
130 for_each_online_cpu(i) {
131 struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);
132
133 if (i == cpu || !sib_cpu_ci->info_list)
134 continue;/* skip if itself or no cacheinfo */
135 sib_leaf = sib_cpu_ci->info_list + index;
136 if (cache_leaves_are_shared(this_leaf, sib_leaf)) {
137 cpumask_set_cpu(cpu, &sib_leaf->shared_cpu_map);
138 cpumask_set_cpu(i, &this_leaf->shared_cpu_map);
139 }
140 }
141 }
142
143 return 0;
144 }
145
cache_shared_cpu_map_remove(unsigned int cpu)146 static void cache_shared_cpu_map_remove(unsigned int cpu)
147 {
148 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
149 struct cacheinfo *this_leaf, *sib_leaf;
150 unsigned int sibling, index;
151
152 for (index = 0; index < cache_leaves(cpu); index++) {
153 this_leaf = this_cpu_ci->info_list + index;
154 for_each_cpu(sibling, &this_leaf->shared_cpu_map) {
155 struct cpu_cacheinfo *sib_cpu_ci;
156
157 if (sibling == cpu) /* skip itself */
158 continue;
159
160 sib_cpu_ci = get_cpu_cacheinfo(sibling);
161 if (!sib_cpu_ci->info_list)
162 continue;
163
164 sib_leaf = sib_cpu_ci->info_list + index;
165 cpumask_clear_cpu(cpu, &sib_leaf->shared_cpu_map);
166 cpumask_clear_cpu(sibling, &this_leaf->shared_cpu_map);
167 }
168 of_node_put(this_leaf->of_node);
169 }
170 }
171
free_cache_attributes(unsigned int cpu)172 static void free_cache_attributes(unsigned int cpu)
173 {
174 if (!per_cpu_cacheinfo(cpu))
175 return;
176
177 cache_shared_cpu_map_remove(cpu);
178
179 kfree(per_cpu_cacheinfo(cpu));
180 per_cpu_cacheinfo(cpu) = NULL;
181 }
182
init_cache_level(unsigned int cpu)183 int __weak init_cache_level(unsigned int cpu)
184 {
185 return -ENOENT;
186 }
187
populate_cache_leaves(unsigned int cpu)188 int __weak populate_cache_leaves(unsigned int cpu)
189 {
190 return -ENOENT;
191 }
192
detect_cache_attributes(unsigned int cpu)193 static int detect_cache_attributes(unsigned int cpu)
194 {
195 int ret;
196
197 if (init_cache_level(cpu) || !cache_leaves(cpu))
198 return -ENOENT;
199
200 per_cpu_cacheinfo(cpu) = kcalloc(cache_leaves(cpu),
201 sizeof(struct cacheinfo), GFP_KERNEL);
202 if (per_cpu_cacheinfo(cpu) == NULL)
203 return -ENOMEM;
204
205 ret = populate_cache_leaves(cpu);
206 if (ret)
207 goto free_ci;
208 /*
209 * For systems using DT for cache hierarchy, of_node and shared_cpu_map
210 * will be set up here only if they are not populated already
211 */
212 ret = cache_shared_cpu_map_setup(cpu);
213 if (ret) {
214 pr_warn("Unable to detect cache hierarchy for CPU %d\n", cpu);
215 goto free_ci;
216 }
217 return 0;
218
219 free_ci:
220 free_cache_attributes(cpu);
221 return ret;
222 }
223
224 /* pointer to cpuX/cache device */
225 static DEFINE_PER_CPU(struct device *, ci_cache_dev);
226 #define per_cpu_cache_dev(cpu) (per_cpu(ci_cache_dev, cpu))
227
228 static cpumask_t cache_dev_map;
229
230 /* pointer to array of devices for cpuX/cache/indexY */
231 static DEFINE_PER_CPU(struct device **, ci_index_dev);
232 #define per_cpu_index_dev(cpu) (per_cpu(ci_index_dev, cpu))
233 #define per_cache_index_dev(cpu, idx) ((per_cpu_index_dev(cpu))[idx])
234
235 #define show_one(file_name, object) \
236 static ssize_t file_name##_show(struct device *dev, \
237 struct device_attribute *attr, char *buf) \
238 { \
239 struct cacheinfo *this_leaf = dev_get_drvdata(dev); \
240 return sprintf(buf, "%u\n", this_leaf->object); \
241 }
242
243 show_one(level, level);
244 show_one(coherency_line_size, coherency_line_size);
245 show_one(number_of_sets, number_of_sets);
246 show_one(physical_line_partition, physical_line_partition);
247 show_one(ways_of_associativity, ways_of_associativity);
248
size_show(struct device * dev,struct device_attribute * attr,char * buf)249 static ssize_t size_show(struct device *dev,
250 struct device_attribute *attr, char *buf)
251 {
252 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
253
254 return sprintf(buf, "%uK\n", this_leaf->size >> 10);
255 }
256
shared_cpumap_show_func(struct device * dev,bool list,char * buf)257 static ssize_t shared_cpumap_show_func(struct device *dev, bool list, char *buf)
258 {
259 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
260 const struct cpumask *mask = &this_leaf->shared_cpu_map;
261
262 return cpumap_print_to_pagebuf(list, buf, mask);
263 }
264
shared_cpu_map_show(struct device * dev,struct device_attribute * attr,char * buf)265 static ssize_t shared_cpu_map_show(struct device *dev,
266 struct device_attribute *attr, char *buf)
267 {
268 return shared_cpumap_show_func(dev, false, buf);
269 }
270
shared_cpu_list_show(struct device * dev,struct device_attribute * attr,char * buf)271 static ssize_t shared_cpu_list_show(struct device *dev,
272 struct device_attribute *attr, char *buf)
273 {
274 return shared_cpumap_show_func(dev, true, buf);
275 }
276
type_show(struct device * dev,struct device_attribute * attr,char * buf)277 static ssize_t type_show(struct device *dev,
278 struct device_attribute *attr, char *buf)
279 {
280 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
281
282 switch (this_leaf->type) {
283 case CACHE_TYPE_DATA:
284 return sprintf(buf, "Data\n");
285 case CACHE_TYPE_INST:
286 return sprintf(buf, "Instruction\n");
287 case CACHE_TYPE_UNIFIED:
288 return sprintf(buf, "Unified\n");
289 default:
290 return -EINVAL;
291 }
292 }
293
allocation_policy_show(struct device * dev,struct device_attribute * attr,char * buf)294 static ssize_t allocation_policy_show(struct device *dev,
295 struct device_attribute *attr, char *buf)
296 {
297 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
298 unsigned int ci_attr = this_leaf->attributes;
299 int n = 0;
300
301 if ((ci_attr & CACHE_READ_ALLOCATE) && (ci_attr & CACHE_WRITE_ALLOCATE))
302 n = sprintf(buf, "ReadWriteAllocate\n");
303 else if (ci_attr & CACHE_READ_ALLOCATE)
304 n = sprintf(buf, "ReadAllocate\n");
305 else if (ci_attr & CACHE_WRITE_ALLOCATE)
306 n = sprintf(buf, "WriteAllocate\n");
307 return n;
308 }
309
write_policy_show(struct device * dev,struct device_attribute * attr,char * buf)310 static ssize_t write_policy_show(struct device *dev,
311 struct device_attribute *attr, char *buf)
312 {
313 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
314 unsigned int ci_attr = this_leaf->attributes;
315 int n = 0;
316
317 if (ci_attr & CACHE_WRITE_THROUGH)
318 n = sprintf(buf, "WriteThrough\n");
319 else if (ci_attr & CACHE_WRITE_BACK)
320 n = sprintf(buf, "WriteBack\n");
321 return n;
322 }
323
324 static DEVICE_ATTR_RO(level);
325 static DEVICE_ATTR_RO(type);
326 static DEVICE_ATTR_RO(coherency_line_size);
327 static DEVICE_ATTR_RO(ways_of_associativity);
328 static DEVICE_ATTR_RO(number_of_sets);
329 static DEVICE_ATTR_RO(size);
330 static DEVICE_ATTR_RO(allocation_policy);
331 static DEVICE_ATTR_RO(write_policy);
332 static DEVICE_ATTR_RO(shared_cpu_map);
333 static DEVICE_ATTR_RO(shared_cpu_list);
334 static DEVICE_ATTR_RO(physical_line_partition);
335
336 static struct attribute *cache_default_attrs[] = {
337 &dev_attr_type.attr,
338 &dev_attr_level.attr,
339 &dev_attr_shared_cpu_map.attr,
340 &dev_attr_shared_cpu_list.attr,
341 &dev_attr_coherency_line_size.attr,
342 &dev_attr_ways_of_associativity.attr,
343 &dev_attr_number_of_sets.attr,
344 &dev_attr_size.attr,
345 &dev_attr_allocation_policy.attr,
346 &dev_attr_write_policy.attr,
347 &dev_attr_physical_line_partition.attr,
348 NULL
349 };
350
351 static umode_t
cache_default_attrs_is_visible(struct kobject * kobj,struct attribute * attr,int unused)352 cache_default_attrs_is_visible(struct kobject *kobj,
353 struct attribute *attr, int unused)
354 {
355 struct device *dev = kobj_to_dev(kobj);
356 struct cacheinfo *this_leaf = dev_get_drvdata(dev);
357 const struct cpumask *mask = &this_leaf->shared_cpu_map;
358 umode_t mode = attr->mode;
359
360 if ((attr == &dev_attr_type.attr) && this_leaf->type)
361 return mode;
362 if ((attr == &dev_attr_level.attr) && this_leaf->level)
363 return mode;
364 if ((attr == &dev_attr_shared_cpu_map.attr) && !cpumask_empty(mask))
365 return mode;
366 if ((attr == &dev_attr_shared_cpu_list.attr) && !cpumask_empty(mask))
367 return mode;
368 if ((attr == &dev_attr_coherency_line_size.attr) &&
369 this_leaf->coherency_line_size)
370 return mode;
371 if ((attr == &dev_attr_ways_of_associativity.attr) &&
372 this_leaf->size) /* allow 0 = full associativity */
373 return mode;
374 if ((attr == &dev_attr_number_of_sets.attr) &&
375 this_leaf->number_of_sets)
376 return mode;
377 if ((attr == &dev_attr_size.attr) && this_leaf->size)
378 return mode;
379 if ((attr == &dev_attr_write_policy.attr) &&
380 (this_leaf->attributes & CACHE_WRITE_POLICY_MASK))
381 return mode;
382 if ((attr == &dev_attr_allocation_policy.attr) &&
383 (this_leaf->attributes & CACHE_ALLOCATE_POLICY_MASK))
384 return mode;
385 if ((attr == &dev_attr_physical_line_partition.attr) &&
386 this_leaf->physical_line_partition)
387 return mode;
388
389 return 0;
390 }
391
392 static const struct attribute_group cache_default_group = {
393 .attrs = cache_default_attrs,
394 .is_visible = cache_default_attrs_is_visible,
395 };
396
397 static const struct attribute_group *cache_default_groups[] = {
398 &cache_default_group,
399 NULL,
400 };
401
402 static const struct attribute_group *cache_private_groups[] = {
403 &cache_default_group,
404 NULL, /* Place holder for private group */
405 NULL,
406 };
407
408 const struct attribute_group *
cache_get_priv_group(struct cacheinfo * this_leaf)409 __weak cache_get_priv_group(struct cacheinfo *this_leaf)
410 {
411 return NULL;
412 }
413
414 static const struct attribute_group **
cache_get_attribute_groups(struct cacheinfo * this_leaf)415 cache_get_attribute_groups(struct cacheinfo *this_leaf)
416 {
417 const struct attribute_group *priv_group =
418 cache_get_priv_group(this_leaf);
419
420 if (!priv_group)
421 return cache_default_groups;
422
423 if (!cache_private_groups[1])
424 cache_private_groups[1] = priv_group;
425
426 return cache_private_groups;
427 }
428
429 /* Add/Remove cache interface for CPU device */
cpu_cache_sysfs_exit(unsigned int cpu)430 static void cpu_cache_sysfs_exit(unsigned int cpu)
431 {
432 int i;
433 struct device *ci_dev;
434
435 if (per_cpu_index_dev(cpu)) {
436 for (i = 0; i < cache_leaves(cpu); i++) {
437 ci_dev = per_cache_index_dev(cpu, i);
438 if (!ci_dev)
439 continue;
440 device_unregister(ci_dev);
441 }
442 kfree(per_cpu_index_dev(cpu));
443 per_cpu_index_dev(cpu) = NULL;
444 }
445 device_unregister(per_cpu_cache_dev(cpu));
446 per_cpu_cache_dev(cpu) = NULL;
447 }
448
cpu_cache_sysfs_init(unsigned int cpu)449 static int cpu_cache_sysfs_init(unsigned int cpu)
450 {
451 struct device *dev = get_cpu_device(cpu);
452
453 if (per_cpu_cacheinfo(cpu) == NULL)
454 return -ENOENT;
455
456 per_cpu_cache_dev(cpu) = cpu_device_create(dev, NULL, NULL, "cache");
457 if (IS_ERR(per_cpu_cache_dev(cpu)))
458 return PTR_ERR(per_cpu_cache_dev(cpu));
459
460 /* Allocate all required memory */
461 per_cpu_index_dev(cpu) = kcalloc(cache_leaves(cpu),
462 sizeof(struct device *), GFP_KERNEL);
463 if (unlikely(per_cpu_index_dev(cpu) == NULL))
464 goto err_out;
465
466 return 0;
467
468 err_out:
469 cpu_cache_sysfs_exit(cpu);
470 return -ENOMEM;
471 }
472
cache_add_dev(unsigned int cpu)473 static int cache_add_dev(unsigned int cpu)
474 {
475 unsigned int i;
476 int rc;
477 struct device *ci_dev, *parent;
478 struct cacheinfo *this_leaf;
479 struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
480 const struct attribute_group **cache_groups;
481
482 rc = cpu_cache_sysfs_init(cpu);
483 if (unlikely(rc < 0))
484 return rc;
485
486 parent = per_cpu_cache_dev(cpu);
487 for (i = 0; i < cache_leaves(cpu); i++) {
488 this_leaf = this_cpu_ci->info_list + i;
489 if (this_leaf->disable_sysfs)
490 continue;
491 cache_groups = cache_get_attribute_groups(this_leaf);
492 ci_dev = cpu_device_create(parent, this_leaf, cache_groups,
493 "index%1u", i);
494 if (IS_ERR(ci_dev)) {
495 rc = PTR_ERR(ci_dev);
496 goto err;
497 }
498 per_cache_index_dev(cpu, i) = ci_dev;
499 }
500 cpumask_set_cpu(cpu, &cache_dev_map);
501
502 return 0;
503 err:
504 cpu_cache_sysfs_exit(cpu);
505 return rc;
506 }
507
cache_remove_dev(unsigned int cpu)508 static void cache_remove_dev(unsigned int cpu)
509 {
510 if (!cpumask_test_cpu(cpu, &cache_dev_map))
511 return;
512 cpumask_clear_cpu(cpu, &cache_dev_map);
513
514 cpu_cache_sysfs_exit(cpu);
515 }
516
cacheinfo_cpu_callback(struct notifier_block * nfb,unsigned long action,void * hcpu)517 static int cacheinfo_cpu_callback(struct notifier_block *nfb,
518 unsigned long action, void *hcpu)
519 {
520 unsigned int cpu = (unsigned long)hcpu;
521 int rc = 0;
522
523 switch (action & ~CPU_TASKS_FROZEN) {
524 case CPU_ONLINE:
525 rc = detect_cache_attributes(cpu);
526 if (!rc)
527 rc = cache_add_dev(cpu);
528 break;
529 case CPU_DEAD:
530 cache_remove_dev(cpu);
531 free_cache_attributes(cpu);
532 break;
533 }
534 return notifier_from_errno(rc);
535 }
536
cacheinfo_sysfs_init(void)537 static int __init cacheinfo_sysfs_init(void)
538 {
539 int cpu, rc = 0;
540
541 cpu_notifier_register_begin();
542
543 for_each_online_cpu(cpu) {
544 rc = detect_cache_attributes(cpu);
545 if (rc)
546 goto out;
547 rc = cache_add_dev(cpu);
548 if (rc) {
549 free_cache_attributes(cpu);
550 pr_err("error populating cacheinfo..cpu%d\n", cpu);
551 goto out;
552 }
553 }
554 __hotcpu_notifier(cacheinfo_cpu_callback, 0);
555
556 out:
557 cpu_notifier_register_done();
558 return rc;
559 }
560
561 device_initcall(cacheinfo_sysfs_init);
562