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1 /*
2  * kernel/lockdep_proc.c
3  *
4  * Runtime locking correctness validator
5  *
6  * Started by Ingo Molnar:
7  *
8  *  Copyright (C) 2006 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
9  *
10  * Code for /proc/lockdep and /proc/lockdep_stats:
11  *
12  */
13 #include <linux/module.h>
14 #include <linux/proc_fs.h>
15 #include <linux/seq_file.h>
16 #include <linux/kallsyms.h>
17 #include <linux/debug_locks.h>
18
19 #include "lockdep_internals.h"
20
21 static void *l_next(struct seq_file *m, void *v, loff_t *pos)
22 {
23         struct lock_class *class = v;
24
25         (*pos)++;
26
27         if (class->lock_entry.next != &all_lock_classes)
28                 class = list_entry(class->lock_entry.next, struct lock_class,
29                                   lock_entry);
30         else
31                 class = NULL;
32         m->private = class;
33
34         return class;
35 }
36
37 static void *l_start(struct seq_file *m, loff_t *pos)
38 {
39         struct lock_class *class = m->private;
40
41         if (&class->lock_entry == all_lock_classes.next)
42                 seq_printf(m, "all lock classes:\n");
43
44         return class;
45 }
46
47 static void l_stop(struct seq_file *m, void *v)
48 {
49 }
50
51 static unsigned long count_forward_deps(struct lock_class *class)
52 {
53         struct lock_list *entry;
54         unsigned long ret = 1;
55
56         /*
57          * Recurse this class's dependency list:
58          */
59         list_for_each_entry(entry, &class->locks_after, entry)
60                 ret += count_forward_deps(entry->class);
61
62         return ret;
63 }
64
65 static unsigned long count_backward_deps(struct lock_class *class)
66 {
67         struct lock_list *entry;
68         unsigned long ret = 1;
69
70         /*
71          * Recurse this class's dependency list:
72          */
73         list_for_each_entry(entry, &class->locks_before, entry)
74                 ret += count_backward_deps(entry->class);
75
76         return ret;
77 }
78
79 static void print_name(struct seq_file *m, struct lock_class *class)
80 {
81         char str[128];
82         const char *name = class->name;
83
84         if (!name) {
85                 name = __get_key_name(class->key, str);
86                 seq_printf(m, "%s", name);
87         } else{
88                 seq_printf(m, "%s", name);
89                 if (class->name_version > 1)
90                         seq_printf(m, "#%d", class->name_version);
91                 if (class->subclass)
92                         seq_printf(m, "/%d", class->subclass);
93         }
94 }
95
96 static int l_show(struct seq_file *m, void *v)
97 {
98         unsigned long nr_forward_deps, nr_backward_deps;
99         struct lock_class *class = m->private;
100         struct lock_list *entry;
101         char c1, c2, c3, c4;
102
103         seq_printf(m, "%p", class->key);
104 #ifdef CONFIG_DEBUG_LOCKDEP
105         seq_printf(m, " OPS:%8ld", class->ops);
106 #endif
107         nr_forward_deps = count_forward_deps(class);
108         seq_printf(m, " FD:%5ld", nr_forward_deps);
109
110         nr_backward_deps = count_backward_deps(class);
111         seq_printf(m, " BD:%5ld", nr_backward_deps);
112
113         get_usage_chars(class, &c1, &c2, &c3, &c4);
114         seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
115
116         seq_printf(m, ": ");
117         print_name(m, class);
118         seq_puts(m, "\n");
119
120         list_for_each_entry(entry, &class->locks_after, entry) {
121                 if (entry->distance == 1) {
122                         seq_printf(m, " -> [%p] ", entry->class);
123                         print_name(m, entry->class);
124                         seq_puts(m, "\n");
125                 }
126         }
127         seq_puts(m, "\n");
128
129         return 0;
130 }
131
132 static const struct seq_operations lockdep_ops = {
133         .start  = l_start,
134         .next   = l_next,
135         .stop   = l_stop,
136         .show   = l_show,
137 };
138
139 static int lockdep_open(struct inode *inode, struct file *file)
140 {
141         int res = seq_open(file, &lockdep_ops);
142         if (!res) {
143                 struct seq_file *m = file->private_data;
144
145                 if (!list_empty(&all_lock_classes))
146                         m->private = list_entry(all_lock_classes.next,
147                                         struct lock_class, lock_entry);
148                 else
149                         m->private = NULL;
150         }
151         return res;
152 }
153
154 static const struct file_operations proc_lockdep_operations = {
155         .open           = lockdep_open,
156         .read           = seq_read,
157         .llseek         = seq_lseek,
158         .release        = seq_release,
159 };
160
161 static void lockdep_stats_debug_show(struct seq_file *m)
162 {
163 #ifdef CONFIG_DEBUG_LOCKDEP
164         unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
165                      hi2 = debug_atomic_read(&hardirqs_off_events),
166                      hr1 = debug_atomic_read(&redundant_hardirqs_on),
167                      hr2 = debug_atomic_read(&redundant_hardirqs_off),
168                      si1 = debug_atomic_read(&softirqs_on_events),
169                      si2 = debug_atomic_read(&softirqs_off_events),
170                      sr1 = debug_atomic_read(&redundant_softirqs_on),
171                      sr2 = debug_atomic_read(&redundant_softirqs_off);
172
173         seq_printf(m, " chain lookup misses:           %11u\n",
174                 debug_atomic_read(&chain_lookup_misses));
175         seq_printf(m, " chain lookup hits:             %11u\n",
176                 debug_atomic_read(&chain_lookup_hits));
177         seq_printf(m, " cyclic checks:                 %11u\n",
178                 debug_atomic_read(&nr_cyclic_checks));
179         seq_printf(m, " cyclic-check recursions:       %11u\n",
180                 debug_atomic_read(&nr_cyclic_check_recursions));
181         seq_printf(m, " find-mask forwards checks:     %11u\n",
182                 debug_atomic_read(&nr_find_usage_forwards_checks));
183         seq_printf(m, " find-mask forwards recursions: %11u\n",
184                 debug_atomic_read(&nr_find_usage_forwards_recursions));
185         seq_printf(m, " find-mask backwards checks:    %11u\n",
186                 debug_atomic_read(&nr_find_usage_backwards_checks));
187         seq_printf(m, " find-mask backwards recursions:%11u\n",
188                 debug_atomic_read(&nr_find_usage_backwards_recursions));
189
190         seq_printf(m, " hardirq on events:             %11u\n", hi1);
191         seq_printf(m, " hardirq off events:            %11u\n", hi2);
192         seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
193         seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
194         seq_printf(m, " softirq on events:             %11u\n", si1);
195         seq_printf(m, " softirq off events:            %11u\n", si2);
196         seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
197         seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
198 #endif
199 }
200
201 static int lockdep_stats_show(struct seq_file *m, void *v)
202 {
203         struct lock_class *class;
204         unsigned long nr_unused = 0, nr_uncategorized = 0,
205                       nr_irq_safe = 0, nr_irq_unsafe = 0,
206                       nr_softirq_safe = 0, nr_softirq_unsafe = 0,
207                       nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
208                       nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
209                       nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
210                       nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
211                       sum_forward_deps = 0, factor = 0;
212
213         list_for_each_entry(class, &all_lock_classes, lock_entry) {
214
215                 if (class->usage_mask == 0)
216                         nr_unused++;
217                 if (class->usage_mask == LOCKF_USED)
218                         nr_uncategorized++;
219                 if (class->usage_mask & LOCKF_USED_IN_IRQ)
220                         nr_irq_safe++;
221                 if (class->usage_mask & LOCKF_ENABLED_IRQS)
222                         nr_irq_unsafe++;
223                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
224                         nr_softirq_safe++;
225                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
226                         nr_softirq_unsafe++;
227                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
228                         nr_hardirq_safe++;
229                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
230                         nr_hardirq_unsafe++;
231                 if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
232                         nr_irq_read_safe++;
233                 if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
234                         nr_irq_read_unsafe++;
235                 if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
236                         nr_softirq_read_safe++;
237                 if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
238                         nr_softirq_read_unsafe++;
239                 if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
240                         nr_hardirq_read_safe++;
241                 if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
242                         nr_hardirq_read_unsafe++;
243
244                 sum_forward_deps += count_forward_deps(class);
245         }
246 #ifdef CONFIG_DEBUG_LOCKDEP
247         DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
248 #endif
249         seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
250                         nr_lock_classes, MAX_LOCKDEP_KEYS);
251         seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
252                         nr_list_entries, MAX_LOCKDEP_ENTRIES);
253         seq_printf(m, " indirect dependencies:         %11lu\n",
254                         sum_forward_deps);
255
256         /*
257          * Total number of dependencies:
258          *
259          * All irq-safe locks may nest inside irq-unsafe locks,
260          * plus all the other known dependencies:
261          */
262         seq_printf(m, " all direct dependencies:       %11lu\n",
263                         nr_irq_unsafe * nr_irq_safe +
264                         nr_hardirq_unsafe * nr_hardirq_safe +
265                         nr_list_entries);
266
267         /*
268          * Estimated factor between direct and indirect
269          * dependencies:
270          */
271         if (nr_list_entries)
272                 factor = sum_forward_deps / nr_list_entries;
273
274         seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
275                         nr_lock_chains, MAX_LOCKDEP_CHAINS);
276
277 #ifdef CONFIG_TRACE_IRQFLAGS
278         seq_printf(m, " in-hardirq chains:             %11u\n",
279                         nr_hardirq_chains);
280         seq_printf(m, " in-softirq chains:             %11u\n",
281                         nr_softirq_chains);
282 #endif
283         seq_printf(m, " in-process chains:             %11u\n",
284                         nr_process_chains);
285         seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
286                         nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
287         seq_printf(m, " combined max dependencies:     %11u\n",
288                         (nr_hardirq_chains + 1) *
289                         (nr_softirq_chains + 1) *
290                         (nr_process_chains + 1)
291         );
292         seq_printf(m, " hardirq-safe locks:            %11lu\n",
293                         nr_hardirq_safe);
294         seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
295                         nr_hardirq_unsafe);
296         seq_printf(m, " softirq-safe locks:            %11lu\n",
297                         nr_softirq_safe);
298         seq_printf(m, " softirq-unsafe locks:          %11lu\n",
299                         nr_softirq_unsafe);
300         seq_printf(m, " irq-safe locks:                %11lu\n",
301                         nr_irq_safe);
302         seq_printf(m, " irq-unsafe locks:              %11lu\n",
303                         nr_irq_unsafe);
304
305         seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
306                         nr_hardirq_read_safe);
307         seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
308                         nr_hardirq_read_unsafe);
309         seq_printf(m, " softirq-read-safe locks:       %11lu\n",
310                         nr_softirq_read_safe);
311         seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
312                         nr_softirq_read_unsafe);
313         seq_printf(m, " irq-read-safe locks:           %11lu\n",
314                         nr_irq_read_safe);
315         seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
316                         nr_irq_read_unsafe);
317
318         seq_printf(m, " uncategorized locks:           %11lu\n",
319                         nr_uncategorized);
320         seq_printf(m, " unused locks:                  %11lu\n",
321                         nr_unused);
322         seq_printf(m, " max locking depth:             %11u\n",
323                         max_lockdep_depth);
324         seq_printf(m, " max recursion depth:           %11u\n",
325                         max_recursion_depth);
326         lockdep_stats_debug_show(m);
327         seq_printf(m, " debug_locks:                   %11u\n",
328                         debug_locks);
329
330         return 0;
331 }
332
333 static int lockdep_stats_open(struct inode *inode, struct file *file)
334 {
335         return single_open(file, lockdep_stats_show, NULL);
336 }
337
338 static const struct file_operations proc_lockdep_stats_operations = {
339         .open           = lockdep_stats_open,
340         .read           = seq_read,
341         .llseek         = seq_lseek,
342         .release        = seq_release,
343 };
344
345 static int __init lockdep_proc_init(void)
346 {
347         struct proc_dir_entry *entry;
348
349         entry = create_proc_entry("lockdep", S_IRUSR, NULL);
350         if (entry)
351                 entry->proc_fops = &proc_lockdep_operations;
352
353         entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
354         if (entry)
355                 entry->proc_fops = &proc_lockdep_stats_operations;
356
357         return 0;
358 }
359
360 __initcall(lockdep_proc_init);
361