1/*
2 * kernel/lockdep_proc.c
3 *
4 * Runtime locking correctness validator
5 *
6 * Started by Ingo Molnar:
7 *
8 *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9 *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
10 *
11 * Code for /proc/lockdep and /proc/lockdep_stats:
12 *
13 */
14#include <linux/export.h>
15#include <linux/proc_fs.h>
16#include <linux/seq_file.h>
17#include <linux/kallsyms.h>
18#include <linux/debug_locks.h>
19#include <linux/vmalloc.h>
20#include <linux/sort.h>
21#include <asm/uaccess.h>
22#include <asm/div64.h>
23
24#include "lockdep_internals.h"
25
26static void *l_next(struct seq_file *m, void *v, loff_t *pos)
27{
28	return seq_list_next(v, &all_lock_classes, pos);
29}
30
31static void *l_start(struct seq_file *m, loff_t *pos)
32{
33	return seq_list_start_head(&all_lock_classes, *pos);
34}
35
36static void l_stop(struct seq_file *m, void *v)
37{
38}
39
40static void print_name(struct seq_file *m, struct lock_class *class)
41{
42	char str[KSYM_NAME_LEN];
43	const char *name = class->name;
44
45	if (!name) {
46		name = __get_key_name(class->key, str);
47		seq_printf(m, "%s", name);
48	} else{
49		seq_printf(m, "%s", name);
50		if (class->name_version > 1)
51			seq_printf(m, "#%d", class->name_version);
52		if (class->subclass)
53			seq_printf(m, "/%d", class->subclass);
54	}
55}
56
57static int l_show(struct seq_file *m, void *v)
58{
59	struct lock_class *class = list_entry(v, struct lock_class, lock_entry);
60	struct lock_list *entry;
61	char usage[LOCK_USAGE_CHARS];
62
63	if (v == &all_lock_classes) {
64		seq_printf(m, "all lock classes:\n");
65		return 0;
66	}
67
68	seq_printf(m, "%p", class->key);
69#ifdef CONFIG_DEBUG_LOCKDEP
70	seq_printf(m, " OPS:%8ld", class->ops);
71#endif
72#ifdef CONFIG_PROVE_LOCKING
73	seq_printf(m, " FD:%5ld", lockdep_count_forward_deps(class));
74	seq_printf(m, " BD:%5ld", lockdep_count_backward_deps(class));
75#endif
76
77	get_usage_chars(class, usage);
78	seq_printf(m, " %s", usage);
79
80	seq_printf(m, ": ");
81	print_name(m, class);
82	seq_puts(m, "\n");
83
84	list_for_each_entry(entry, &class->locks_after, entry) {
85		if (entry->distance == 1) {
86			seq_printf(m, " -> [%p] ", entry->class->key);
87			print_name(m, entry->class);
88			seq_puts(m, "\n");
89		}
90	}
91	seq_puts(m, "\n");
92
93	return 0;
94}
95
96static const struct seq_operations lockdep_ops = {
97	.start	= l_start,
98	.next	= l_next,
99	.stop	= l_stop,
100	.show	= l_show,
101};
102
103static int lockdep_open(struct inode *inode, struct file *file)
104{
105	return seq_open(file, &lockdep_ops);
106}
107
108static const struct file_operations proc_lockdep_operations = {
109	.open		= lockdep_open,
110	.read		= seq_read,
111	.llseek		= seq_lseek,
112	.release	= seq_release,
113};
114
115#ifdef CONFIG_PROVE_LOCKING
116static void *lc_start(struct seq_file *m, loff_t *pos)
117{
118	if (*pos == 0)
119		return SEQ_START_TOKEN;
120
121	if (*pos - 1 < nr_lock_chains)
122		return lock_chains + (*pos - 1);
123
124	return NULL;
125}
126
127static void *lc_next(struct seq_file *m, void *v, loff_t *pos)
128{
129	(*pos)++;
130	return lc_start(m, pos);
131}
132
133static void lc_stop(struct seq_file *m, void *v)
134{
135}
136
137static int lc_show(struct seq_file *m, void *v)
138{
139	struct lock_chain *chain = v;
140	struct lock_class *class;
141	int i;
142
143	if (v == SEQ_START_TOKEN) {
144		seq_printf(m, "all lock chains:\n");
145		return 0;
146	}
147
148	seq_printf(m, "irq_context: %d\n", 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
164static 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
171static int lockdep_chains_open(struct inode *inode, struct file *file)
172{
173	return seq_open(file, &lockdep_chains_ops);
174}
175
176static const struct file_operations proc_lockdep_chains_operations = {
177	.open		= lockdep_chains_open,
178	.read		= seq_read,
179	.llseek		= seq_lseek,
180	.release	= seq_release,
181};
182#endif /* CONFIG_PROVE_LOCKING */
183
184static void lockdep_stats_debug_show(struct seq_file *m)
185{
186#ifdef CONFIG_DEBUG_LOCKDEP
187	unsigned long long hi1 = debug_atomic_read(hardirqs_on_events),
188			   hi2 = debug_atomic_read(hardirqs_off_events),
189			   hr1 = debug_atomic_read(redundant_hardirqs_on),
190			   hr2 = debug_atomic_read(redundant_hardirqs_off),
191			   si1 = debug_atomic_read(softirqs_on_events),
192			   si2 = debug_atomic_read(softirqs_off_events),
193			   sr1 = debug_atomic_read(redundant_softirqs_on),
194			   sr2 = debug_atomic_read(redundant_softirqs_off);
195
196	seq_printf(m, " chain lookup misses:           %11llu\n",
197		debug_atomic_read(chain_lookup_misses));
198	seq_printf(m, " chain lookup hits:             %11llu\n",
199		debug_atomic_read(chain_lookup_hits));
200	seq_printf(m, " cyclic checks:                 %11llu\n",
201		debug_atomic_read(nr_cyclic_checks));
202	seq_printf(m, " find-mask forwards checks:     %11llu\n",
203		debug_atomic_read(nr_find_usage_forwards_checks));
204	seq_printf(m, " find-mask backwards checks:    %11llu\n",
205		debug_atomic_read(nr_find_usage_backwards_checks));
206
207	seq_printf(m, " hardirq on events:             %11llu\n", hi1);
208	seq_printf(m, " hardirq off events:            %11llu\n", hi2);
209	seq_printf(m, " redundant hardirq ons:         %11llu\n", hr1);
210	seq_printf(m, " redundant hardirq offs:        %11llu\n", hr2);
211	seq_printf(m, " softirq on events:             %11llu\n", si1);
212	seq_printf(m, " softirq off events:            %11llu\n", si2);
213	seq_printf(m, " redundant softirq ons:         %11llu\n", sr1);
214	seq_printf(m, " redundant softirq offs:        %11llu\n", sr2);
215#endif
216}
217
218static int lockdep_stats_show(struct seq_file *m, void *v)
219{
220	struct lock_class *class;
221	unsigned long nr_unused = 0, nr_uncategorized = 0,
222		      nr_irq_safe = 0, nr_irq_unsafe = 0,
223		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
224		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
225		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
226		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
227		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
228		      sum_forward_deps = 0;
229
230	list_for_each_entry(class, &all_lock_classes, lock_entry) {
231
232		if (class->usage_mask == 0)
233			nr_unused++;
234		if (class->usage_mask == LOCKF_USED)
235			nr_uncategorized++;
236		if (class->usage_mask & LOCKF_USED_IN_IRQ)
237			nr_irq_safe++;
238		if (class->usage_mask & LOCKF_ENABLED_IRQ)
239			nr_irq_unsafe++;
240		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
241			nr_softirq_safe++;
242		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ)
243			nr_softirq_unsafe++;
244		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
245			nr_hardirq_safe++;
246		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ)
247			nr_hardirq_unsafe++;
248		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
249			nr_irq_read_safe++;
250		if (class->usage_mask & LOCKF_ENABLED_IRQ_READ)
251			nr_irq_read_unsafe++;
252		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
253			nr_softirq_read_safe++;
254		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQ_READ)
255			nr_softirq_read_unsafe++;
256		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
257			nr_hardirq_read_safe++;
258		if (class->usage_mask & LOCKF_ENABLED_HARDIRQ_READ)
259			nr_hardirq_read_unsafe++;
260
261#ifdef CONFIG_PROVE_LOCKING
262		sum_forward_deps += lockdep_count_forward_deps(class);
263#endif
264	}
265#ifdef CONFIG_DEBUG_LOCKDEP
266	DEBUG_LOCKS_WARN_ON(debug_atomic_read(nr_unused_locks) != nr_unused);
267#endif
268	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
269			nr_lock_classes, MAX_LOCKDEP_KEYS);
270	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
271			nr_list_entries, MAX_LOCKDEP_ENTRIES);
272	seq_printf(m, " indirect dependencies:         %11lu\n",
273			sum_forward_deps);
274
275	/*
276	 * Total number of dependencies:
277	 *
278	 * All irq-safe locks may nest inside irq-unsafe locks,
279	 * plus all the other known dependencies:
280	 */
281	seq_printf(m, " all direct dependencies:       %11lu\n",
282			nr_irq_unsafe * nr_irq_safe +
283			nr_hardirq_unsafe * nr_hardirq_safe +
284			nr_list_entries);
285
286#ifdef CONFIG_PROVE_LOCKING
287	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
288			nr_lock_chains, MAX_LOCKDEP_CHAINS);
289	seq_printf(m, " dependency chain hlocks:       %11d [max: %lu]\n",
290			nr_chain_hlocks, MAX_LOCKDEP_CHAIN_HLOCKS);
291#endif
292
293#ifdef CONFIG_TRACE_IRQFLAGS
294	seq_printf(m, " in-hardirq chains:             %11u\n",
295			nr_hardirq_chains);
296	seq_printf(m, " in-softirq chains:             %11u\n",
297			nr_softirq_chains);
298#endif
299	seq_printf(m, " in-process chains:             %11u\n",
300			nr_process_chains);
301	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
302			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
303	seq_printf(m, " combined max dependencies:     %11u\n",
304			(nr_hardirq_chains + 1) *
305			(nr_softirq_chains + 1) *
306			(nr_process_chains + 1)
307	);
308	seq_printf(m, " hardirq-safe locks:            %11lu\n",
309			nr_hardirq_safe);
310	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
311			nr_hardirq_unsafe);
312	seq_printf(m, " softirq-safe locks:            %11lu\n",
313			nr_softirq_safe);
314	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
315			nr_softirq_unsafe);
316	seq_printf(m, " irq-safe locks:                %11lu\n",
317			nr_irq_safe);
318	seq_printf(m, " irq-unsafe locks:              %11lu\n",
319			nr_irq_unsafe);
320
321	seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
322			nr_hardirq_read_safe);
323	seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
324			nr_hardirq_read_unsafe);
325	seq_printf(m, " softirq-read-safe locks:       %11lu\n",
326			nr_softirq_read_safe);
327	seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
328			nr_softirq_read_unsafe);
329	seq_printf(m, " irq-read-safe locks:           %11lu\n",
330			nr_irq_read_safe);
331	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
332			nr_irq_read_unsafe);
333
334	seq_printf(m, " uncategorized locks:           %11lu\n",
335			nr_uncategorized);
336	seq_printf(m, " unused locks:                  %11lu\n",
337			nr_unused);
338	seq_printf(m, " max locking depth:             %11u\n",
339			max_lockdep_depth);
340#ifdef CONFIG_PROVE_LOCKING
341	seq_printf(m, " max bfs queue depth:           %11u\n",
342			max_bfs_queue_depth);
343#endif
344	lockdep_stats_debug_show(m);
345	seq_printf(m, " debug_locks:                   %11u\n",
346			debug_locks);
347
348	return 0;
349}
350
351static int lockdep_stats_open(struct inode *inode, struct file *file)
352{
353	return single_open(file, lockdep_stats_show, NULL);
354}
355
356static const struct file_operations proc_lockdep_stats_operations = {
357	.open		= lockdep_stats_open,
358	.read		= seq_read,
359	.llseek		= seq_lseek,
360	.release	= single_release,
361};
362
363#ifdef CONFIG_LOCK_STAT
364
365struct lock_stat_data {
366	struct lock_class *class;
367	struct lock_class_stats stats;
368};
369
370struct lock_stat_seq {
371	struct lock_stat_data *iter_end;
372	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
373};
374
375/*
376 * sort on absolute number of contentions
377 */
378static int lock_stat_cmp(const void *l, const void *r)
379{
380	const struct lock_stat_data *dl = l, *dr = r;
381	unsigned long nl, nr;
382
383	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
384	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
385
386	return nr - nl;
387}
388
389static void seq_line(struct seq_file *m, char c, int offset, int length)
390{
391	int i;
392
393	for (i = 0; i < offset; i++)
394		seq_puts(m, " ");
395	for (i = 0; i < length; i++)
396		seq_printf(m, "%c", c);
397	seq_puts(m, "\n");
398}
399
400static void snprint_time(char *buf, size_t bufsiz, s64 nr)
401{
402	s64 div;
403	s32 rem;
404
405	nr += 5; /* for display rounding */
406	div = div_s64_rem(nr, 1000, &rem);
407	snprintf(buf, bufsiz, "%lld.%02d", (long long)div, (int)rem/10);
408}
409
410static void seq_time(struct seq_file *m, s64 time)
411{
412	char num[15];
413
414	snprint_time(num, sizeof(num), time);
415	seq_printf(m, " %14s", num);
416}
417
418static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
419{
420	seq_printf(m, "%14lu", lt->nr);
421	seq_time(m, lt->min);
422	seq_time(m, lt->max);
423	seq_time(m, lt->total);
424	seq_time(m, lt->nr ? div_s64(lt->total, lt->nr) : 0);
425}
426
427static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
428{
429	char name[39];
430	struct lock_class *class;
431	struct lock_class_stats *stats;
432	int i, namelen;
433
434	class = data->class;
435	stats = &data->stats;
436
437	namelen = 38;
438	if (class->name_version > 1)
439		namelen -= 2; /* XXX truncates versions > 9 */
440	if (class->subclass)
441		namelen -= 2;
442
443	if (!class->name) {
444		char str[KSYM_NAME_LEN];
445		const char *key_name;
446
447		key_name = __get_key_name(class->key, str);
448		snprintf(name, namelen, "%s", key_name);
449	} else {
450		snprintf(name, namelen, "%s", class->name);
451	}
452	namelen = strlen(name);
453	if (class->name_version > 1) {
454		snprintf(name+namelen, 3, "#%d", class->name_version);
455		namelen += 2;
456	}
457	if (class->subclass) {
458		snprintf(name+namelen, 3, "/%d", class->subclass);
459		namelen += 2;
460	}
461
462	if (stats->write_holdtime.nr) {
463		if (stats->read_holdtime.nr)
464			seq_printf(m, "%38s-W:", name);
465		else
466			seq_printf(m, "%40s:", name);
467
468		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
469		seq_lock_time(m, &stats->write_waittime);
470		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
471		seq_lock_time(m, &stats->write_holdtime);
472		seq_puts(m, "\n");
473	}
474
475	if (stats->read_holdtime.nr) {
476		seq_printf(m, "%38s-R:", name);
477		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
478		seq_lock_time(m, &stats->read_waittime);
479		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
480		seq_lock_time(m, &stats->read_holdtime);
481		seq_puts(m, "\n");
482	}
483
484	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
485		return;
486
487	if (stats->read_holdtime.nr)
488		namelen += 2;
489
490	for (i = 0; i < LOCKSTAT_POINTS; i++) {
491		char ip[32];
492
493		if (class->contention_point[i] == 0)
494			break;
495
496		if (!i)
497			seq_line(m, '-', 40-namelen, namelen);
498
499		snprintf(ip, sizeof(ip), "[<%p>]",
500				(void *)class->contention_point[i]);
501		seq_printf(m, "%40s %14lu %29s %pS\n",
502			   name, stats->contention_point[i],
503			   ip, (void *)class->contention_point[i]);
504	}
505	for (i = 0; i < LOCKSTAT_POINTS; i++) {
506		char ip[32];
507
508		if (class->contending_point[i] == 0)
509			break;
510
511		if (!i)
512			seq_line(m, '-', 40-namelen, namelen);
513
514		snprintf(ip, sizeof(ip), "[<%p>]",
515				(void *)class->contending_point[i]);
516		seq_printf(m, "%40s %14lu %29s %pS\n",
517			   name, stats->contending_point[i],
518			   ip, (void *)class->contending_point[i]);
519	}
520	if (i) {
521		seq_puts(m, "\n");
522		seq_line(m, '.', 0, 40 + 1 + 12 * (14 + 1));
523		seq_puts(m, "\n");
524	}
525}
526
527static void seq_header(struct seq_file *m)
528{
529	seq_puts(m, "lock_stat version 0.4\n");
530
531	if (unlikely(!debug_locks))
532		seq_printf(m, "*WARNING* lock debugging disabled!! - possibly due to a lockdep warning\n");
533
534	seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
535	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s %14s %14s "
536			"%14s %14s\n",
537			"class name",
538			"con-bounces",
539			"contentions",
540			"waittime-min",
541			"waittime-max",
542			"waittime-total",
543			"waittime-avg",
544			"acq-bounces",
545			"acquisitions",
546			"holdtime-min",
547			"holdtime-max",
548			"holdtime-total",
549			"holdtime-avg");
550	seq_line(m, '-', 0, 40 + 1 + 12 * (14 + 1));
551	seq_printf(m, "\n");
552}
553
554static void *ls_start(struct seq_file *m, loff_t *pos)
555{
556	struct lock_stat_seq *data = m->private;
557	struct lock_stat_data *iter;
558
559	if (*pos == 0)
560		return SEQ_START_TOKEN;
561
562	iter = data->stats + (*pos - 1);
563	if (iter >= data->iter_end)
564		iter = NULL;
565
566	return iter;
567}
568
569static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
570{
571	(*pos)++;
572	return ls_start(m, pos);
573}
574
575static void ls_stop(struct seq_file *m, void *v)
576{
577}
578
579static int ls_show(struct seq_file *m, void *v)
580{
581	if (v == SEQ_START_TOKEN)
582		seq_header(m);
583	else
584		seq_stats(m, v);
585
586	return 0;
587}
588
589static const struct seq_operations lockstat_ops = {
590	.start	= ls_start,
591	.next	= ls_next,
592	.stop	= ls_stop,
593	.show	= ls_show,
594};
595
596static int lock_stat_open(struct inode *inode, struct file *file)
597{
598	int res;
599	struct lock_class *class;
600	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
601
602	if (!data)
603		return -ENOMEM;
604
605	res = seq_open(file, &lockstat_ops);
606	if (!res) {
607		struct lock_stat_data *iter = data->stats;
608		struct seq_file *m = file->private_data;
609
610		list_for_each_entry(class, &all_lock_classes, lock_entry) {
611			iter->class = class;
612			iter->stats = lock_stats(class);
613			iter++;
614		}
615		data->iter_end = iter;
616
617		sort(data->stats, data->iter_end - data->stats,
618				sizeof(struct lock_stat_data),
619				lock_stat_cmp, NULL);
620
621		m->private = data;
622	} else
623		vfree(data);
624
625	return res;
626}
627
628static ssize_t lock_stat_write(struct file *file, const char __user *buf,
629			       size_t count, loff_t *ppos)
630{
631	struct lock_class *class;
632	char c;
633
634	if (count) {
635		if (get_user(c, buf))
636			return -EFAULT;
637
638		if (c != '0')
639			return count;
640
641		list_for_each_entry(class, &all_lock_classes, lock_entry)
642			clear_lock_stats(class);
643	}
644	return count;
645}
646
647static int lock_stat_release(struct inode *inode, struct file *file)
648{
649	struct seq_file *seq = file->private_data;
650
651	vfree(seq->private);
652	return seq_release(inode, file);
653}
654
655static const struct file_operations proc_lock_stat_operations = {
656	.open		= lock_stat_open,
657	.write		= lock_stat_write,
658	.read		= seq_read,
659	.llseek		= seq_lseek,
660	.release	= lock_stat_release,
661};
662#endif /* CONFIG_LOCK_STAT */
663
664static int __init lockdep_proc_init(void)
665{
666	proc_create("lockdep", S_IRUSR, NULL, &proc_lockdep_operations);
667#ifdef CONFIG_PROVE_LOCKING
668	proc_create("lockdep_chains", S_IRUSR, NULL,
669		    &proc_lockdep_chains_operations);
670#endif
671	proc_create("lockdep_stats", S_IRUSR, NULL,
672		    &proc_lockdep_stats_operations);
673
674#ifdef CONFIG_LOCK_STAT
675	proc_create("lock_stat", S_IRUSR | S_IWUSR, NULL,
676		    &proc_lock_stat_operations);
677#endif
678
679	return 0;
680}
681
682__initcall(lockdep_proc_init);
683
684