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1 | /* | |
2 | * Copyright 2005, Red Hat, Inc., Ingo Molnar | |
3 | * Released under the General Public License (GPL). | |
4 | * | |
5 | * This file contains the spinlock/rwlock implementations for | |
6 | * DEBUG_SPINLOCK. | |
7 | */ | |
8 | ||
9 | #include <linux/spinlock.h> | |
10 | #include <linux/nmi.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/debug_locks.h> | |
13 | #include <linux/delay.h> | |
14 | #include <linux/module.h> | |
15 | ||
16 | void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name, | |
17 | struct lock_class_key *key) | |
18 | { | |
19 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
20 | /* | |
21 | * Make sure we are not reinitializing a held lock: | |
22 | */ | |
23 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); | |
24 | lockdep_init_map(&lock->dep_map, name, key, 0); | |
25 | #endif | |
26 | lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED; | |
27 | lock->magic = SPINLOCK_MAGIC; | |
28 | lock->owner = SPINLOCK_OWNER_INIT; | |
29 | lock->owner_cpu = -1; | |
30 | } | |
31 | ||
32 | EXPORT_SYMBOL(__raw_spin_lock_init); | |
33 | ||
34 | void __rwlock_init(rwlock_t *lock, const char *name, | |
35 | struct lock_class_key *key) | |
36 | { | |
37 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
38 | /* | |
39 | * Make sure we are not reinitializing a held lock: | |
40 | */ | |
41 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); | |
42 | lockdep_init_map(&lock->dep_map, name, key, 0); | |
43 | #endif | |
44 | lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED; | |
45 | lock->magic = RWLOCK_MAGIC; | |
46 | lock->owner = SPINLOCK_OWNER_INIT; | |
47 | lock->owner_cpu = -1; | |
48 | } | |
49 | ||
50 | EXPORT_SYMBOL(__rwlock_init); | |
51 | ||
52 | static void spin_dump(raw_spinlock_t *lock, const char *msg) | |
53 | { | |
54 | struct task_struct *owner = NULL; | |
55 | ||
56 | if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT) | |
57 | owner = lock->owner; | |
58 | printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n", | |
59 | msg, raw_smp_processor_id(), | |
60 | current->comm, task_pid_nr(current)); | |
61 | printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, " | |
62 | ".owner_cpu: %d\n", | |
63 | lock, lock->magic, | |
64 | owner ? owner->comm : "<none>", | |
65 | owner ? task_pid_nr(owner) : -1, | |
66 | lock->owner_cpu); | |
67 | dump_stack(); | |
68 | } | |
69 | ||
70 | static void spin_bug(raw_spinlock_t *lock, const char *msg) | |
71 | { | |
72 | if (!debug_locks_off()) | |
73 | return; | |
74 | ||
75 | spin_dump(lock, msg); | |
76 | } | |
77 | ||
78 | #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg) | |
79 | ||
80 | static inline void | |
81 | debug_spin_lock_before(raw_spinlock_t *lock) | |
82 | { | |
83 | SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); | |
84 | SPIN_BUG_ON(lock->owner == current, lock, "recursion"); | |
85 | SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), | |
86 | lock, "cpu recursion"); | |
87 | } | |
88 | ||
89 | static inline void debug_spin_lock_after(raw_spinlock_t *lock) | |
90 | { | |
91 | lock->owner_cpu = raw_smp_processor_id(); | |
92 | lock->owner = current; | |
93 | } | |
94 | ||
95 | static inline void debug_spin_unlock(raw_spinlock_t *lock) | |
96 | { | |
97 | SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); | |
98 | SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked"); | |
99 | SPIN_BUG_ON(lock->owner != current, lock, "wrong owner"); | |
100 | SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), | |
101 | lock, "wrong CPU"); | |
102 | lock->owner = SPINLOCK_OWNER_INIT; | |
103 | lock->owner_cpu = -1; | |
104 | } | |
105 | ||
106 | static void __spin_lock_debug(raw_spinlock_t *lock) | |
107 | { | |
108 | u64 i; | |
109 | u64 loops = loops_per_jiffy * HZ; | |
110 | int print_once = 1; | |
111 | ||
112 | for (;;) { | |
113 | for (i = 0; i < loops; i++) { | |
114 | if (arch_spin_trylock(&lock->raw_lock)) | |
115 | return; | |
116 | __delay(1); | |
117 | } | |
118 | /* lockup suspected: */ | |
119 | if (print_once) { | |
120 | print_once = 0; | |
121 | spin_dump(lock, "lockup"); | |
122 | #ifdef CONFIG_SMP | |
123 | trigger_all_cpu_backtrace(); | |
124 | #endif | |
125 | } | |
126 | } | |
127 | } | |
128 | ||
129 | void do_raw_spin_lock(raw_spinlock_t *lock) | |
130 | { | |
131 | debug_spin_lock_before(lock); | |
132 | if (unlikely(!arch_spin_trylock(&lock->raw_lock))) | |
133 | __spin_lock_debug(lock); | |
134 | debug_spin_lock_after(lock); | |
135 | } | |
136 | ||
137 | int do_raw_spin_trylock(raw_spinlock_t *lock) | |
138 | { | |
139 | int ret = arch_spin_trylock(&lock->raw_lock); | |
140 | ||
141 | if (ret) | |
142 | debug_spin_lock_after(lock); | |
143 | #ifndef CONFIG_SMP | |
144 | /* | |
145 | * Must not happen on UP: | |
146 | */ | |
147 | SPIN_BUG_ON(!ret, lock, "trylock failure on UP"); | |
148 | #endif | |
149 | return ret; | |
150 | } | |
151 | ||
152 | void do_raw_spin_unlock(raw_spinlock_t *lock) | |
153 | { | |
154 | debug_spin_unlock(lock); | |
155 | arch_spin_unlock(&lock->raw_lock); | |
156 | } | |
157 | ||
158 | static void rwlock_bug(rwlock_t *lock, const char *msg) | |
159 | { | |
160 | if (!debug_locks_off()) | |
161 | return; | |
162 | ||
163 | printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n", | |
164 | msg, raw_smp_processor_id(), current->comm, | |
165 | task_pid_nr(current), lock); | |
166 | dump_stack(); | |
167 | } | |
168 | ||
169 | #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg) | |
170 | ||
171 | #if 0 /* __write_lock_debug() can lock up - maybe this can too? */ | |
172 | static void __read_lock_debug(rwlock_t *lock) | |
173 | { | |
174 | u64 i; | |
175 | u64 loops = loops_per_jiffy * HZ; | |
176 | int print_once = 1; | |
177 | ||
178 | for (;;) { | |
179 | for (i = 0; i < loops; i++) { | |
180 | if (arch_read_trylock(&lock->raw_lock)) | |
181 | return; | |
182 | __delay(1); | |
183 | } | |
184 | /* lockup suspected: */ | |
185 | if (print_once) { | |
186 | print_once = 0; | |
187 | printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, " | |
188 | "%s/%d, %p\n", | |
189 | raw_smp_processor_id(), current->comm, | |
190 | current->pid, lock); | |
191 | dump_stack(); | |
192 | } | |
193 | } | |
194 | } | |
195 | #endif | |
196 | ||
197 | void do_raw_read_lock(rwlock_t *lock) | |
198 | { | |
199 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
200 | arch_read_lock(&lock->raw_lock); | |
201 | } | |
202 | ||
203 | int do_raw_read_trylock(rwlock_t *lock) | |
204 | { | |
205 | int ret = arch_read_trylock(&lock->raw_lock); | |
206 | ||
207 | #ifndef CONFIG_SMP | |
208 | /* | |
209 | * Must not happen on UP: | |
210 | */ | |
211 | RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); | |
212 | #endif | |
213 | return ret; | |
214 | } | |
215 | ||
216 | void do_raw_read_unlock(rwlock_t *lock) | |
217 | { | |
218 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
219 | arch_read_unlock(&lock->raw_lock); | |
220 | } | |
221 | ||
222 | static inline void debug_write_lock_before(rwlock_t *lock) | |
223 | { | |
224 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
225 | RWLOCK_BUG_ON(lock->owner == current, lock, "recursion"); | |
226 | RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), | |
227 | lock, "cpu recursion"); | |
228 | } | |
229 | ||
230 | static inline void debug_write_lock_after(rwlock_t *lock) | |
231 | { | |
232 | lock->owner_cpu = raw_smp_processor_id(); | |
233 | lock->owner = current; | |
234 | } | |
235 | ||
236 | static inline void debug_write_unlock(rwlock_t *lock) | |
237 | { | |
238 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
239 | RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner"); | |
240 | RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), | |
241 | lock, "wrong CPU"); | |
242 | lock->owner = SPINLOCK_OWNER_INIT; | |
243 | lock->owner_cpu = -1; | |
244 | } | |
245 | ||
246 | #if 0 /* This can cause lockups */ | |
247 | static void __write_lock_debug(rwlock_t *lock) | |
248 | { | |
249 | u64 i; | |
250 | u64 loops = loops_per_jiffy * HZ; | |
251 | int print_once = 1; | |
252 | ||
253 | for (;;) { | |
254 | for (i = 0; i < loops; i++) { | |
255 | if (arch_write_trylock(&lock->raw_lock)) | |
256 | return; | |
257 | __delay(1); | |
258 | } | |
259 | /* lockup suspected: */ | |
260 | if (print_once) { | |
261 | print_once = 0; | |
262 | printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, " | |
263 | "%s/%d, %p\n", | |
264 | raw_smp_processor_id(), current->comm, | |
265 | current->pid, lock); | |
266 | dump_stack(); | |
267 | } | |
268 | } | |
269 | } | |
270 | #endif | |
271 | ||
272 | void do_raw_write_lock(rwlock_t *lock) | |
273 | { | |
274 | debug_write_lock_before(lock); | |
275 | arch_write_lock(&lock->raw_lock); | |
276 | debug_write_lock_after(lock); | |
277 | } | |
278 | ||
279 | int do_raw_write_trylock(rwlock_t *lock) | |
280 | { | |
281 | int ret = arch_write_trylock(&lock->raw_lock); | |
282 | ||
283 | if (ret) | |
284 | debug_write_lock_after(lock); | |
285 | #ifndef CONFIG_SMP | |
286 | /* | |
287 | * Must not happen on UP: | |
288 | */ | |
289 | RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); | |
290 | #endif | |
291 | return ret; | |
292 | } | |
293 | ||
294 | void do_raw_write_unlock(rwlock_t *lock) | |
295 | { | |
296 | debug_write_unlock(lock); | |
297 | arch_write_unlock(&lock->raw_lock); | |
298 | } |