tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Extract CPU cache information and expose them via sysfs.
3 *
4 * Copyright IBM Corp. 2012
5 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
6 */
7
8#include <linux/notifier.h>
9#include <linux/seq_file.h>
10#include <linux/init.h>
11#include <linux/list.h>
12#include <linux/slab.h>
13#include <linux/cpu.h>
14#include <asm/facility.h>
15
16struct cache {
17 unsigned long size;
18 unsigned int line_size;
19 unsigned int associativity;
20 unsigned int nr_sets;
21 unsigned int level : 3;
22 unsigned int type : 2;
23 unsigned int private : 1;
24 struct list_head list;
25};
26
27struct cache_dir {
28 struct kobject *kobj;
29 struct cache_index_dir *index;
30};
31
32struct cache_index_dir {
33 struct kobject kobj;
34 int cpu;
35 struct cache *cache;
36 struct cache_index_dir *next;
37};
38
39enum {
40 CACHE_SCOPE_NOTEXISTS,
41 CACHE_SCOPE_PRIVATE,
42 CACHE_SCOPE_SHARED,
43 CACHE_SCOPE_RESERVED,
44};
45
46enum {
47 CACHE_TYPE_SEPARATE,
48 CACHE_TYPE_DATA,
49 CACHE_TYPE_INSTRUCTION,
50 CACHE_TYPE_UNIFIED,
51};
52
53enum {
54 EXTRACT_TOPOLOGY,
55 EXTRACT_LINE_SIZE,
56 EXTRACT_SIZE,
57 EXTRACT_ASSOCIATIVITY,
58};
59
60enum {
61 CACHE_TI_UNIFIED = 0,
62 CACHE_TI_DATA = 0,
63 CACHE_TI_INSTRUCTION,
64};
65
66struct cache_info {
67 unsigned char : 4;
68 unsigned char scope : 2;
69 unsigned char type : 2;
70};
71
72#define CACHE_MAX_LEVEL 8
73
74union cache_topology {
75 struct cache_info ci[CACHE_MAX_LEVEL];
76 unsigned long long raw;
77};
78
79static const char * const cache_type_string[] = {
80 "Data",
81 "Instruction",
82 "Unified",
83};
84
85static struct cache_dir *cache_dir_cpu[NR_CPUS];
86static LIST_HEAD(cache_list);
87
88void show_cacheinfo(struct seq_file *m)
89{
90 struct cache *cache;
91 int index = 0;
92
93 list_for_each_entry(cache, &cache_list, list) {
94 seq_printf(m, "cache%-11d: ", index);
95 seq_printf(m, "level=%d ", cache->level);
96 seq_printf(m, "type=%s ", cache_type_string[cache->type]);
97 seq_printf(m, "scope=%s ", cache->private ? "Private" : "Shared");
98 seq_printf(m, "size=%luK ", cache->size >> 10);
99 seq_printf(m, "line_size=%u ", cache->line_size);
100 seq_printf(m, "associativity=%d", cache->associativity);
101 seq_puts(m, "\n");
102 index++;
103 }
104}
105
106static inline unsigned long ecag(int ai, int li, int ti)
107{
108 unsigned long cmd, val;
109
110 cmd = ai << 4 | li << 1 | ti;
111 asm volatile(".insn rsy,0xeb000000004c,%0,0,0(%1)" /* ecag */
112 : "=d" (val) : "a" (cmd));
113 return val;
114}
115
116static int __init cache_add(int level, int private, int type)
117{
118 struct cache *cache;
119 int ti;
120
121 cache = kzalloc(sizeof(*cache), GFP_KERNEL);
122 if (!cache)
123 return -ENOMEM;
124 if (type == CACHE_TYPE_INSTRUCTION)
125 ti = CACHE_TI_INSTRUCTION;
126 else
127 ti = CACHE_TI_UNIFIED;
128 cache->size = ecag(EXTRACT_SIZE, level, ti);
129 cache->line_size = ecag(EXTRACT_LINE_SIZE, level, ti);
130 cache->associativity = ecag(EXTRACT_ASSOCIATIVITY, level, ti);
131 cache->nr_sets = cache->size / cache->associativity;
132 cache->nr_sets /= cache->line_size;
133 cache->private = private;
134 cache->level = level + 1;
135 cache->type = type - 1;
136 list_add_tail(&cache->list, &cache_list);
137 return 0;
138}
139
140static void __init cache_build_info(void)
141{
142 struct cache *cache, *next;
143 union cache_topology ct;
144 int level, private, rc;
145
146 ct.raw = ecag(EXTRACT_TOPOLOGY, 0, 0);
147 for (level = 0; level < CACHE_MAX_LEVEL; level++) {
148 switch (ct.ci[level].scope) {
149 case CACHE_SCOPE_NOTEXISTS:
150 case CACHE_SCOPE_RESERVED:
151 return;
152 case CACHE_SCOPE_SHARED:
153 private = 0;
154 break;
155 case CACHE_SCOPE_PRIVATE:
156 private = 1;
157 break;
158 }
159 if (ct.ci[level].type == CACHE_TYPE_SEPARATE) {
160 rc = cache_add(level, private, CACHE_TYPE_DATA);
161 rc |= cache_add(level, private, CACHE_TYPE_INSTRUCTION);
162 } else {
163 rc = cache_add(level, private, ct.ci[level].type);
164 }
165 if (rc)
166 goto error;
167 }
168 return;
169error:
170 list_for_each_entry_safe(cache, next, &cache_list, list) {
171 list_del(&cache->list);
172 kfree(cache);
173 }
174}
175
176static struct cache_dir *__cpuinit cache_create_cache_dir(int cpu)
177{
178 struct cache_dir *cache_dir;
179 struct kobject *kobj = NULL;
180 struct device *dev;
181
182 dev = get_cpu_device(cpu);
183 if (!dev)
184 goto out;
185 kobj = kobject_create_and_add("cache", &dev->kobj);
186 if (!kobj)
187 goto out;
188 cache_dir = kzalloc(sizeof(*cache_dir), GFP_KERNEL);
189 if (!cache_dir)
190 goto out;
191 cache_dir->kobj = kobj;
192 cache_dir_cpu[cpu] = cache_dir;
193 return cache_dir;
194out:
195 kobject_put(kobj);
196 return NULL;
197}
198
199static struct cache_index_dir *kobj_to_cache_index_dir(struct kobject *kobj)
200{
201 return container_of(kobj, struct cache_index_dir, kobj);
202}
203
204static void cache_index_release(struct kobject *kobj)
205{
206 struct cache_index_dir *index;
207
208 index = kobj_to_cache_index_dir(kobj);
209 kfree(index);
210}
211
212static ssize_t cache_index_show(struct kobject *kobj,
213 struct attribute *attr, char *buf)
214{
215 struct kobj_attribute *kobj_attr;
216
217 kobj_attr = container_of(attr, struct kobj_attribute, attr);
218 return kobj_attr->show(kobj, kobj_attr, buf);
219}
220
221#define DEFINE_CACHE_ATTR(_name, _format, _value) \
222static ssize_t cache_##_name##_show(struct kobject *kobj, \
223 struct kobj_attribute *attr, \
224 char *buf) \
225{ \
226 struct cache_index_dir *index; \
227 \
228 index = kobj_to_cache_index_dir(kobj); \
229 return sprintf(buf, _format, _value); \
230} \
231static struct kobj_attribute cache_##_name##_attr = \
232 __ATTR(_name, 0444, cache_##_name##_show, NULL);
233
234DEFINE_CACHE_ATTR(size, "%luK\n", index->cache->size >> 10);
235DEFINE_CACHE_ATTR(coherency_line_size, "%u\n", index->cache->line_size);
236DEFINE_CACHE_ATTR(number_of_sets, "%u\n", index->cache->nr_sets);
237DEFINE_CACHE_ATTR(ways_of_associativity, "%u\n", index->cache->associativity);
238DEFINE_CACHE_ATTR(type, "%s\n", cache_type_string[index->cache->type]);
239DEFINE_CACHE_ATTR(level, "%d\n", index->cache->level);
240
241static ssize_t shared_cpu_map_func(struct kobject *kobj, int type, char *buf)
242{
243 struct cache_index_dir *index;
244 int len;
245
246 index = kobj_to_cache_index_dir(kobj);
247 len = type ?
248 cpulist_scnprintf(buf, PAGE_SIZE - 2, cpumask_of(index->cpu)) :
249 cpumask_scnprintf(buf, PAGE_SIZE - 2, cpumask_of(index->cpu));
250 len += sprintf(&buf[len], "\n");
251 return len;
252}
253
254static ssize_t shared_cpu_map_show(struct kobject *kobj,
255 struct kobj_attribute *attr, char *buf)
256{
257 return shared_cpu_map_func(kobj, 0, buf);
258}
259static struct kobj_attribute cache_shared_cpu_map_attr =
260 __ATTR(shared_cpu_map, 0444, shared_cpu_map_show, NULL);
261
262static ssize_t shared_cpu_list_show(struct kobject *kobj,
263 struct kobj_attribute *attr, char *buf)
264{
265 return shared_cpu_map_func(kobj, 1, buf);
266}
267static struct kobj_attribute cache_shared_cpu_list_attr =
268 __ATTR(shared_cpu_list, 0444, shared_cpu_list_show, NULL);
269
270static struct attribute *cache_index_default_attrs[] = {
271 &cache_type_attr.attr,
272 &cache_size_attr.attr,
273 &cache_number_of_sets_attr.attr,
274 &cache_ways_of_associativity_attr.attr,
275 &cache_level_attr.attr,
276 &cache_coherency_line_size_attr.attr,
277 &cache_shared_cpu_map_attr.attr,
278 &cache_shared_cpu_list_attr.attr,
279 NULL,
280};
281
282static const struct sysfs_ops cache_index_ops = {
283 .show = cache_index_show,
284};
285
286static struct kobj_type cache_index_type = {
287 .sysfs_ops = &cache_index_ops,
288 .release = cache_index_release,
289 .default_attrs = cache_index_default_attrs,
290};
291
292static int __cpuinit cache_create_index_dir(struct cache_dir *cache_dir,
293 struct cache *cache, int index,
294 int cpu)
295{
296 struct cache_index_dir *index_dir;
297 int rc;
298
299 index_dir = kzalloc(sizeof(*index_dir), GFP_KERNEL);
300 if (!index_dir)
301 return -ENOMEM;
302 index_dir->cache = cache;
303 index_dir->cpu = cpu;
304 rc = kobject_init_and_add(&index_dir->kobj, &cache_index_type,
305 cache_dir->kobj, "index%d", index);
306 if (rc)
307 goto out;
308 index_dir->next = cache_dir->index;
309 cache_dir->index = index_dir;
310 return 0;
311out:
312 kfree(index_dir);
313 return rc;
314}
315
316static int __cpuinit cache_add_cpu(int cpu)
317{
318 struct cache_dir *cache_dir;
319 struct cache *cache;
320 int rc, index = 0;
321
322 if (list_empty(&cache_list))
323 return 0;
324 cache_dir = cache_create_cache_dir(cpu);
325 if (!cache_dir)
326 return -ENOMEM;
327 list_for_each_entry(cache, &cache_list, list) {
328 if (!cache->private)
329 break;
330 rc = cache_create_index_dir(cache_dir, cache, index, cpu);
331 if (rc)
332 return rc;
333 index++;
334 }
335 return 0;
336}
337
338static void __cpuinit cache_remove_cpu(int cpu)
339{
340 struct cache_index_dir *index, *next;
341 struct cache_dir *cache_dir;
342
343 cache_dir = cache_dir_cpu[cpu];
344 if (!cache_dir)
345 return;
346 index = cache_dir->index;
347 while (index) {
348 next = index->next;
349 kobject_put(&index->kobj);
350 index = next;
351 }
352 kobject_put(cache_dir->kobj);
353 kfree(cache_dir);
354 cache_dir_cpu[cpu] = NULL;
355}
356
357static int __cpuinit cache_hotplug(struct notifier_block *nfb,
358 unsigned long action, void *hcpu)
359{
360 int cpu = (long)hcpu;
361 int rc = 0;
362
363 switch (action & ~CPU_TASKS_FROZEN) {
364 case CPU_ONLINE:
365 rc = cache_add_cpu(cpu);
366 if (rc)
367 cache_remove_cpu(cpu);
368 break;
369 case CPU_DEAD:
370 cache_remove_cpu(cpu);
371 break;
372 }
373 return rc ? NOTIFY_BAD : NOTIFY_OK;
374}
375
376static int __init cache_init(void)
377{
378 int cpu;
379
380 if (!test_facility(34))
381 return 0;
382 cache_build_info();
383 for_each_online_cpu(cpu)
384 cache_add_cpu(cpu);
385 hotcpu_notifier(cache_hotplug, 0);
386 return 0;
387}
388device_initcall(cache_init);