drm/amdgpu: Add support for RAS XGMI err query
[linux-2.6-microblaze.git] / kernel / locking / lockdep_proc.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * kernel/lockdep_proc.c
4  *
5  * Runtime locking correctness validator
6  *
7  * Started by Ingo Molnar:
8  *
9  *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
10  *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra
11  *
12  * Code for /proc/lockdep and /proc/lockdep_stats:
13  *
14  */
15 #include <linux/export.h>
16 #include <linux/proc_fs.h>
17 #include <linux/seq_file.h>
18 #include <linux/kallsyms.h>
19 #include <linux/debug_locks.h>
20 #include <linux/vmalloc.h>
21 #include <linux/sort.h>
22 #include <linux/uaccess.h>
23 #include <asm/div64.h>
24
25 #include "lockdep_internals.h"
26
27 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
28 {
29         return seq_list_next(v, &all_lock_classes, pos);
30 }
31
32 static void *l_start(struct seq_file *m, loff_t *pos)
33 {
34         return seq_list_start_head(&all_lock_classes, *pos);
35 }
36
37 static void l_stop(struct seq_file *m, void *v)
38 {
39 }
40
41 static void print_name(struct seq_file *m, struct lock_class *class)
42 {
43         char str[KSYM_NAME_LEN];
44         const char *name = class->name;
45
46         if (!name) {
47                 name = __get_key_name(class->key, str);
48                 seq_printf(m, "%s", name);
49         } else{
50                 seq_printf(m, "%s", name);
51                 if (class->name_version > 1)
52                         seq_printf(m, "#%d", class->name_version);
53                 if (class->subclass)
54                         seq_printf(m, "/%d", class->subclass);
55         }
56 }
57
58 static int l_show(struct seq_file *m, void *v)
59 {
60         struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
61         struct lock_list *entry;
62         char usage[LOCK_USAGE_CHARS];
63
64         if (v == &all_lock_classes) {
65                 seq_printf(m, "all lock classes:\n");
66                 return 0;
67         }
68
69         seq_printf(m, "%p", class->key);
70 #ifdef CONFIG_DEBUG_LOCKDEP
71         seq_printf(m, " OPS:%8ld", debug_class_ops_read(class));
72 #endif
73         if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
74                 seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
75                 seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
76
77                 get_usage_chars(class, usage);
78                 seq_printf(m, " %s", usage);
79         }
80
81         seq_printf(m, ": ");
82         print_name(m, class);
83         seq_puts(m, "\n");
84
85         if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
86                 list_for_each_entry(entry, &class->locks_after, entry) {
87                         if (entry->distance == 1) {
88                                 seq_printf(m, " -> [%p] ", entry->class->key);
89                                 print_name(m, entry->class);
90                                 seq_puts(m, "\n");
91                         }
92                 }
93                 seq_puts(m, "\n");
94         }
95
96         return 0;
97 }
98
99 static const struct seq_operations lockdep_ops = {
100         .start  = l_start,
101         .next   = l_next,
102         .stop   = l_stop,
103         .show   = l_show,
104 };
105
106 #ifdef CONFIG_PROVE_LOCKING
107 static void *lc_start(struct seq_file *m, loff_t *pos)
108 {
109         if (*pos < 0)
110                 return NULL;
111
112         if (*pos == 0)
113                 return SEQ_START_TOKEN;
114
115         return lock_chains + (*pos - 1);
116 }
117
118 static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
119 {
120         *pos = lockdep_next_lockchain(*pos - 1) + 1;
121         return lc_start(m, pos);
122 }
123
124 static void lc_stop(struct seq_file *m, void *v)
125 {
126 }
127
128 static int lc_show(struct seq_file *m, void *v)
129 {
130         struct lock_chain *chain = v;
131         struct lock_class *class;
132         int i;
133         static const char * const irq_strs[] = {
134                 [0]                          = "0",
135                 [LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq",
136                 [LOCK_CHAIN_SOFTIRQ_CONTEXT] = "softirq",
137                 [LOCK_CHAIN_SOFTIRQ_CONTEXT|
138                  LOCK_CHAIN_HARDIRQ_CONTEXT] = "hardirq|softirq",
139         };
140
141         if (v == SEQ_START_TOKEN) {
142                 if (!nr_free_chain_hlocks)
143                         seq_printf(m, "(buggered) ");
144                 seq_printf(m, "all lock chains:\n");
145                 return 0;
146         }
147
148         seq_printf(m, "irq_context: %s\n", irq_strs[chain->irq_context]);
149
150         for (i = 0; i < chain->depth; i++) {
151                 class = lock_chain_get_class(chain, i);
152                 if (!class->key)
153                         continue;
154
155                 seq_printf(m, "[%p] ", class->key);
156                 print_name(m, class);
157                 seq_puts(m, "\n");
158         }
159         seq_puts(m, "\n");
160
161         return 0;
162 }
163
164 static const struct seq_operations lockdep_chains_ops = {
165         .start  = lc_start,
166         .next   = lc_next,
167         .stop   = lc_stop,
168         .show   = lc_show,
169 };
170 #endif /* CONFIG_PROVE_LOCKING */
171
172 static void lockdep_stats_debug_show(struct seq_file *m)
173 {
174 #ifdef CONFIG_DEBUG_LOCKDEP
175         unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
176                            hi2 = debug_atomic_read(hardirqs_off_events),
177                            hr1 = debug_atomic_read(redundant_hardirqs_on),
178                            hr2 = debug_atomic_read(redundant_hardirqs_off),
179                            si1 = debug_atomic_read(softirqs_on_events),
180                            si2 = debug_atomic_read(softirqs_off_events),
181                            sr1 = debug_atomic_read(redundant_softirqs_on),
182                            sr2 = debug_atomic_read(redundant_softirqs_off);
183
184         seq_printf(m, " chain lookup misses:           %11llu\n",
185                 debug_atomic_read(chain_lookup_misses));
186         seq_printf(m, " chain lookup hits:             %11llu\n",
187                 debug_atomic_read(chain_lookup_hits));
188         seq_printf(m, " cyclic checks:                 %11llu\n",
189                 debug_atomic_read(nr_cyclic_checks));
190         seq_printf(m, " redundant checks:              %11llu\n",
191                 debug_atomic_read(nr_redundant_checks));
192         seq_printf(m, " redundant links:               %11llu\n",
193                 debug_atomic_read(nr_redundant));
194         seq_printf(m, " find-mask forwards checks:     %11llu\n",
195                 debug_atomic_read(nr_find_usage_forwards_checks));
196         seq_printf(m, " find-mask backwards checks:    %11llu\n",
197                 debug_atomic_read(nr_find_usage_backwards_checks));
198
199         seq_printf(m, " hardirq on events:             %11llu\n", hi1);
200         seq_printf(m, " hardirq off events:            %11llu\n", hi2);
201         seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
202         seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
203         seq_printf(m, " softirq on events:             %11llu\n", si1);
204         seq_printf(m, " softirq off events:            %11llu\n", si2);
205         seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
206         seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
207 #endif
208 }
209
210 static int lockdep_stats_show(struct seq_file *m, void *v)
211 {
212         unsigned long nr_unused = 0, nr_uncategorized = 0,
213                       nr_irq_safe = 0, nr_irq_unsafe = 0,
214                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
215                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
216                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
217                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
218                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
219                       sum_forward_deps = 0;
220
221 #ifdef CONFIG_PROVE_LOCKING
222         struct lock_class *class;
223
224         list_for_each_entry(class, &all_lock_classes, lock_entry) {
225
226                 if (class->usage_mask == 0)
227                         nr_unused++;
228                 if (class->usage_mask == LOCKF_USED)
229                         nr_uncategorized++;
230                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
231                         nr_irq_safe++;
232                 if (class->usage_mask & LOCKF_ENABLED_IRQ)
233                         nr_irq_unsafe++;
234                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
235                         nr_softirq_safe++;
236                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
237                         nr_softirq_unsafe++;
238                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
239                         nr_hardirq_safe++;
240                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
241                         nr_hardirq_unsafe++;
242                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
243                         nr_irq_read_safe++;
244                 if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
245                         nr_irq_read_unsafe++;
246                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
247                         nr_softirq_read_safe++;
248                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
249                         nr_softirq_read_unsafe++;
250                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
251                         nr_hardirq_read_safe++;
252                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
253                         nr_hardirq_read_unsafe++;
254
255                 sum_forward_deps += lockdep_count_forward_deps(class);
256         }
257 #ifdef CONFIG_DEBUG_LOCKDEP
258         DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
259 #endif
260
261 #endif
262         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
263                         nr_lock_classes, MAX_LOCKDEP_KEYS);
264         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
265                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
266         seq_printf(m, " indirect dependencies:         %11lu\n",
267                         sum_forward_deps);
268
269         /*
270          * Total number of dependencies:
271          *
272          * All irq-safe locks may nest inside irq-unsafe locks,
273          * plus all the other known dependencies:
274          */
275         seq_printf(m, " all direct dependencies:       %11lu\n",
276                         nr_irq_unsafe * nr_irq_safe +
277                         nr_hardirq_unsafe * nr_hardirq_safe +
278                         nr_list_entries);
279
280 #ifdef CONFIG_PROVE_LOCKING
281         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
282                         lock_chain_count(), MAX_LOCKDEP_CHAINS);
283         seq_printf(m, " dependency chain hlocks used:  %11lu [max: %lu]\n",
284                         MAX_LOCKDEP_CHAIN_HLOCKS -
285                         (nr_free_chain_hlocks + nr_lost_chain_hlocks),
286                         MAX_LOCKDEP_CHAIN_HLOCKS);
287         seq_printf(m, " dependency chain hlocks lost:  %11u\n",
288                         nr_lost_chain_hlocks);
289 #endif
290
291 #ifdef CONFIG_TRACE_IRQFLAGS
292         seq_printf(m, " in-hardirq chains:             %11u\n",
293                         nr_hardirq_chains);
294         seq_printf(m, " in-softirq chains:             %11u\n",
295                         nr_softirq_chains);
296 #endif
297         seq_printf(m, " in-process chains:             %11u\n",
298                         nr_process_chains);
299         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
300                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
301 #if defined(CONFIG_TRACE_IRQFLAGS) && defined(CONFIG_PROVE_LOCKING)
302         seq_printf(m, " number of stack traces:        %11llu\n",
303                    lockdep_stack_trace_count());
304         seq_printf(m, " number of stack hash chains:   %11llu\n",
305                    lockdep_stack_hash_count());
306 #endif
307         seq_printf(m, " combined max dependencies:     %11u\n",
308                         (nr_hardirq_chains + 1) *
309                         (nr_softirq_chains + 1) *
310                         (nr_process_chains + 1)
311         );
312         seq_printf(m, " hardirq-safe locks:            %11lu\n",
313                         nr_hardirq_safe);
314         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
315                         nr_hardirq_unsafe);
316         seq_printf(m, " softirq-safe locks:            %11lu\n",
317                         nr_softirq_safe);
318         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
319                         nr_softirq_unsafe);
320         seq_printf(m, " irq-safe locks:                %11lu\n",
321                         nr_irq_safe);
322         seq_printf(m, " irq-unsafe locks:              %11lu\n",
323                         nr_irq_unsafe);
324
325         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
326                         nr_hardirq_read_safe);
327         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
328                         nr_hardirq_read_unsafe);
329         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
330                         nr_softirq_read_safe);
331         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
332                         nr_softirq_read_unsafe);
333         seq_printf(m, " irq-read-safe locks:           %11lu\n",
334                         nr_irq_read_safe);
335         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
336                         nr_irq_read_unsafe);
337
338         seq_printf(m, " uncategorized locks:           %11lu\n",
339                         nr_uncategorized);
340         seq_printf(m, " unused locks:                  %11lu\n",
341                         nr_unused);
342         seq_printf(m, " max locking depth:             %11u\n",
343                         max_lockdep_depth);
344 #ifdef CONFIG_PROVE_LOCKING
345         seq_printf(m, " max bfs queue depth:           %11u\n",
346                         max_bfs_queue_depth);
347 #endif
348         lockdep_stats_debug_show(m);
349         seq_printf(m, " debug_locks:                   %11u\n",
350                         debug_locks);
351
352         /*
353          * Zapped classes and lockdep data buffers reuse statistics.
354          */
355         seq_puts(m, "\n");
356         seq_printf(m, " zapped classes:                %11lu\n",
357                         nr_zapped_classes);
358 #ifdef CONFIG_PROVE_LOCKING
359         seq_printf(m, " zapped lock chains:            %11lu\n",
360                         nr_zapped_lock_chains);
361         seq_printf(m, " large chain blocks:            %11u\n",
362                         nr_large_chain_blocks);
363 #endif
364         return 0;
365 }
366
367 #ifdef CONFIG_LOCK_STAT
368
369 struct lock_stat_data {
370         struct lock_class *class;
371         struct lock_class_stats stats;
372 };
373
374 struct lock_stat_seq {
375         struct lock_stat_data *iter_end;
376         struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
377 };
378
379 /*
380  * sort on absolute number of contentions
381  */
382 static int lock_stat_cmp(const void *l, const void *r)
383 {
384         const struct lock_stat_data *dl = l, *dr = r;
385         unsigned long nl, nr;
386
387         nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
388         nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
389
390         return nr - nl;
391 }
392
393 static void seq_line(struct seq_file *m, char c, int offset, int length)
394 {
395         int i;
396
397         for (i = 0; i < offset; i++)
398                 seq_puts(m, " ");
399         for (i = 0; i < length; i++)
400                 seq_printf(m, "%c", c);
401         seq_puts(m, "\n");
402 }
403
404 static void snprint_time(char *buf, size_t bufsiz, s64 nr)
405 {
406         s64 div;
407         s32 rem;
408
409         nr += 5; /* for display rounding */
410         div = div_s64_rem(nr, 1000, &rem);
411         snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
412 }
413
414 static void seq_time(struct seq_file *m, s64 time)
415 {
416         char num[15];
417
418         snprint_time(num, sizeof(num), time);
419         seq_printf(m, " %14s", num);
420 }
421
422 static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
423 {
424         seq_printf(m, "%14lu", lt->nr);
425         seq_time(m, lt->min);
426         seq_time(m, lt->max);
427         seq_time(m, lt->total);
428         seq_time(m, lt->nr ? div64_u64(lt->total, lt->nr) : 0);
429 }
430
431 static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
432 {
433         const struct lockdep_subclass_key *ckey;
434         struct lock_class_stats *stats;
435         struct lock_class *class;
436         const char *cname;
437         int i, namelen;
438         char name[39];
439
440         class = data->class;
441         stats = &data->stats;
442
443         namelen = 38;
444         if (class->name_version > 1)
445                 namelen -= 2; /* XXX truncates versions > 9 */
446         if (class->subclass)
447                 namelen -= 2;
448
449         rcu_read_lock_sched();
450         cname = rcu_dereference_sched(class->name);
451         ckey  = rcu_dereference_sched(class->key);
452
453         if (!cname && !ckey) {
454                 rcu_read_unlock_sched();
455                 return;
456
457         } else if (!cname) {
458                 char str[KSYM_NAME_LEN];
459                 const char *key_name;
460
461                 key_name = __get_key_name(ckey, str);
462                 snprintf(name, namelen, "%s", key_name);
463         } else {
464                 snprintf(name, namelen, "%s", cname);
465         }
466         rcu_read_unlock_sched();
467
468         namelen = strlen(name);
469         if (class->name_version > 1) {
470                 snprintf(name+namelen, 3, "#%d", class->name_version);
471                 namelen += 2;
472         }
473         if (class->subclass) {
474                 snprintf(name+namelen, 3, "/%d", class->subclass);
475                 namelen += 2;
476         }
477
478         if (stats->write_holdtime.nr) {
479                 if (stats->read_holdtime.nr)
480                         seq_printf(m, "%38s-W:", name);
481                 else
482                         seq_printf(m, "%40s:", name);
483
484                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
485                 seq_lock_time(m, &stats->write_waittime);
486                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
487                 seq_lock_time(m, &stats->write_holdtime);
488                 seq_puts(m, "\n");
489         }
490
491         if (stats->read_holdtime.nr) {
492                 seq_printf(m, "%38s-R:", name);
493                 seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
494                 seq_lock_time(m, &stats->read_waittime);
495                 seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
496                 seq_lock_time(m, &stats->read_holdtime);
497                 seq_puts(m, "\n");
498         }
499
500         if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
501                 return;
502
503         if (stats->read_holdtime.nr)
504                 namelen += 2;
505
506         for (i = 0; i < LOCKSTAT_POINTS; i++) {
507                 char ip[32];
508
509                 if (class->contention_point[i] == 0)
510                         break;
511
512                 if (!i)
513                         seq_line(m, '-', 40-namelen, namelen);
514
515                 snprintf(ip, sizeof(ip), "[<%p>]",
516                                 (void *)class->contention_point[i]);
517                 seq_printf(m, "%40s %14lu %29s %pS\n",
518                            name, stats->contention_point[i],
519                            ip, (void *)class->contention_point[i]);
520         }
521         for (i = 0; i < LOCKSTAT_POINTS; i++) {
522                 char ip[32];
523
524                 if (class->contending_point[i] == 0)
525                         break;
526
527                 if (!i)
528                         seq_line(m, '-', 40-namelen, namelen);
529
530                 snprintf(ip, sizeof(ip), "[<%p>]",
531                                 (void *)class->contending_point[i]);
532                 seq_printf(m, "%40s %14lu %29s %pS\n",
533                            name, stats->contending_point[i],
534                            ip, (void *)class->contending_point[i]);
535         }
536         if (i) {
537                 seq_puts(m, "\n");
538                 seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
539                 seq_puts(m, "\n");
540         }
541 }
542
543 static void seq_header(struct seq_file *m)
544 {
545         seq_puts(m, "lock_stat version 0.4\n");
546
547         if (unlikely(!debug_locks))
548                 seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
549
550         seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
551         seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
552                         "%14s %14s\n",
553                         "class name",
554                         "con-bounces",
555                         "contentions",
556                         "waittime-min",
557                         "waittime-max",
558                         "waittime-total",
559                         "waittime-avg",
560                         "acq-bounces",
561                         "acquisitions",
562                         "holdtime-min",
563                         "holdtime-max",
564                         "holdtime-total",
565                         "holdtime-avg");
566         seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
567         seq_printf(m, "\n");
568 }
569
570 static void *ls_start(struct seq_file *m, loff_t *pos)
571 {
572         struct lock_stat_seq *data = m->private;
573         struct lock_stat_data *iter;
574
575         if (*pos == 0)
576                 return SEQ_START_TOKEN;
577
578         iter = data->stats + (*pos - 1);
579         if (iter >= data->iter_end)
580                 iter = NULL;
581
582         return iter;
583 }
584
585 static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
586 {
587         (*pos)++;
588         return ls_start(m, pos);
589 }
590
591 static void ls_stop(struct seq_file *m, void *v)
592 {
593 }
594
595 static int ls_show(struct seq_file *m, void *v)
596 {
597         if (v == SEQ_START_TOKEN)
598                 seq_header(m);
599         else
600                 seq_stats(m, v);
601
602         return 0;
603 }
604
605 static const struct seq_operations lockstat_ops = {
606         .start  = ls_start,
607         .next   = ls_next,
608         .stop   = ls_stop,
609         .show   = ls_show,
610 };
611
612 static int lock_stat_open(struct inode *inode, struct file *file)
613 {
614         int res;
615         struct lock_class *class;
616         struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
617
618         if (!data)
619                 return -ENOMEM;
620
621         res = seq_open(file, &lockstat_ops);
622         if (!res) {
623                 struct lock_stat_data *iter = data->stats;
624                 struct seq_file *m = file->private_data;
625
626                 list_for_each_entry(class, &all_lock_classes, lock_entry) {
627                         iter->class = class;
628                         iter->stats = lock_stats(class);
629                         iter++;
630                 }
631                 data->iter_end = iter;
632
633                 sort(data->stats, data->iter_end - data->stats,
634                                 sizeof(struct lock_stat_data),
635                                 lock_stat_cmp, NULL);
636
637                 m->private = data;
638         } else
639                 vfree(data);
640
641         return res;
642 }
643
644 static ssize_t lock_stat_write(struct file *file, const char __user *buf,
645                                size_t count, loff_t *ppos)
646 {
647         struct lock_class *class;
648         char c;
649
650         if (count) {
651                 if (get_user(c, buf))
652                         return -EFAULT;
653
654                 if (c != '0')
655                         return count;
656
657                 list_for_each_entry(class, &all_lock_classes, lock_entry)
658                         clear_lock_stats(class);
659         }
660         return count;
661 }
662
663 static int lock_stat_release(struct inode *inode, struct file *file)
664 {
665         struct seq_file *seq = file->private_data;
666
667         vfree(seq->private);
668         return seq_release(inode, file);
669 }
670
671 static const struct proc_ops lock_stat_proc_ops = {
672         .proc_open      = lock_stat_open,
673         .proc_write     = lock_stat_write,
674         .proc_read      = seq_read,
675         .proc_lseek     = seq_lseek,
676         .proc_release   = lock_stat_release,
677 };
678 #endif /* CONFIG_LOCK_STAT */
679
680 static int __init lockdep_proc_init(void)
681 {
682         proc_create_seq("lockdep", S_IRUSR, NULL, &lockdep_ops);
683 #ifdef CONFIG_PROVE_LOCKING
684         proc_create_seq("lockdep_chains", S_IRUSR, NULL, &lockdep_chains_ops);
685 #endif
686         proc_create_single("lockdep_stats", S_IRUSR, NULL, lockdep_stats_show);
687 #ifdef CONFIG_LOCK_STAT
688         proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL, &lock_stat_proc_ops);
689 #endif
690
691         return 0;
692 }
693
694 __initcall(lockdep_proc_init);
695