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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 __spin_lock_init(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 = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; |
27 | lock->magic = SPINLOCK_MAGIC; |
28 | lock->owner = SPINLOCK_OWNER_INIT; |
29 | lock->owner_cpu = -1; |
30 | } |
31 | |
32 | EXPORT_SYMBOL(__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 = (raw_rwlock_t) __RAW_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_bug(spinlock_t *lock, const char *msg) |
53 | { |
54 | struct task_struct *owner = NULL; |
55 | |
56 | if (!debug_locks_off()) |
57 | return; |
58 | |
59 | if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT) |
60 | owner = lock->owner; |
61 | printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n", |
62 | msg, raw_smp_processor_id(), |
63 | current->comm, task_pid_nr(current)); |
64 | printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, " |
65 | ".owner_cpu: %d\n", |
66 | lock, lock->magic, |
67 | owner ? owner->comm : "<none>", |
68 | owner ? task_pid_nr(owner) : -1, |
69 | lock->owner_cpu); |
70 | dump_stack(); |
71 | } |
72 | |
73 | #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg) |
74 | |
75 | static inline void |
76 | debug_spin_lock_before(spinlock_t *lock) |
77 | { |
78 | SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); |
79 | SPIN_BUG_ON(lock->owner == current, lock, "recursion"); |
80 | SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), |
81 | lock, "cpu recursion"); |
82 | } |
83 | |
84 | static inline void debug_spin_lock_after(spinlock_t *lock) |
85 | { |
86 | lock->owner_cpu = raw_smp_processor_id(); |
87 | lock->owner = current; |
88 | } |
89 | |
90 | static inline void debug_spin_unlock(spinlock_t *lock) |
91 | { |
92 | SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); |
93 | SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked"); |
94 | SPIN_BUG_ON(lock->owner != current, lock, "wrong owner"); |
95 | SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), |
96 | lock, "wrong CPU"); |
97 | lock->owner = SPINLOCK_OWNER_INIT; |
98 | lock->owner_cpu = -1; |
99 | } |
100 | |
101 | static void __spin_lock_debug(spinlock_t *lock) |
102 | { |
103 | u64 i; |
104 | u64 loops = loops_per_jiffy * HZ; |
105 | int print_once = 1; |
106 | |
107 | for (;;) { |
108 | for (i = 0; i < loops; i++) { |
109 | if (__raw_spin_trylock(&lock->raw_lock)) |
110 | return; |
111 | __delay(1); |
112 | } |
113 | /* lockup suspected: */ |
114 | if (print_once) { |
115 | print_once = 0; |
116 | printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, " |
117 | "%s/%d, %p\n", |
118 | raw_smp_processor_id(), current->comm, |
119 | task_pid_nr(current), lock); |
120 | dump_stack(); |
121 | #ifdef CONFIG_SMP |
122 | trigger_all_cpu_backtrace(); |
123 | #endif |
124 | } |
125 | } |
126 | } |
127 | |
128 | void _raw_spin_lock(spinlock_t *lock) |
129 | { |
130 | debug_spin_lock_before(lock); |
131 | if (unlikely(!__raw_spin_trylock(&lock->raw_lock))) |
132 | __spin_lock_debug(lock); |
133 | debug_spin_lock_after(lock); |
134 | } |
135 | |
136 | int _raw_spin_trylock(spinlock_t *lock) |
137 | { |
138 | int ret = __raw_spin_trylock(&lock->raw_lock); |
139 | |
140 | if (ret) |
141 | debug_spin_lock_after(lock); |
142 | #ifndef CONFIG_SMP |
143 | /* |
144 | * Must not happen on UP: |
145 | */ |
146 | SPIN_BUG_ON(!ret, lock, "trylock failure on UP"); |
147 | #endif |
148 | return ret; |
149 | } |
150 | |
151 | void _raw_spin_unlock(spinlock_t *lock) |
152 | { |
153 | debug_spin_unlock(lock); |
154 | __raw_spin_unlock(&lock->raw_lock); |
155 | } |
156 | |
157 | static void rwlock_bug(rwlock_t *lock, const char *msg) |
158 | { |
159 | if (!debug_locks_off()) |
160 | return; |
161 | |
162 | printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n", |
163 | msg, raw_smp_processor_id(), current->comm, |
164 | task_pid_nr(current), lock); |
165 | dump_stack(); |
166 | } |
167 | |
168 | #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg) |
169 | |
170 | #if 0 /* __write_lock_debug() can lock up - maybe this can too? */ |
171 | static void __read_lock_debug(rwlock_t *lock) |
172 | { |
173 | u64 i; |
174 | u64 loops = loops_per_jiffy * HZ; |
175 | int print_once = 1; |
176 | |
177 | for (;;) { |
178 | for (i = 0; i < loops; i++) { |
179 | if (__raw_read_trylock(&lock->raw_lock)) |
180 | return; |
181 | __delay(1); |
182 | } |
183 | /* lockup suspected: */ |
184 | if (print_once) { |
185 | print_once = 0; |
186 | printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, " |
187 | "%s/%d, %p\n", |
188 | raw_smp_processor_id(), current->comm, |
189 | current->pid, lock); |
190 | dump_stack(); |
191 | } |
192 | } |
193 | } |
194 | #endif |
195 | |
196 | void _raw_read_lock(rwlock_t *lock) |
197 | { |
198 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); |
199 | __raw_read_lock(&lock->raw_lock); |
200 | } |
201 | |
202 | int _raw_read_trylock(rwlock_t *lock) |
203 | { |
204 | int ret = __raw_read_trylock(&lock->raw_lock); |
205 | |
206 | #ifndef CONFIG_SMP |
207 | /* |
208 | * Must not happen on UP: |
209 | */ |
210 | RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); |
211 | #endif |
212 | return ret; |
213 | } |
214 | |
215 | void _raw_read_unlock(rwlock_t *lock) |
216 | { |
217 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); |
218 | __raw_read_unlock(&lock->raw_lock); |
219 | } |
220 | |
221 | static inline void debug_write_lock_before(rwlock_t *lock) |
222 | { |
223 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); |
224 | RWLOCK_BUG_ON(lock->owner == current, lock, "recursion"); |
225 | RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), |
226 | lock, "cpu recursion"); |
227 | } |
228 | |
229 | static inline void debug_write_lock_after(rwlock_t *lock) |
230 | { |
231 | lock->owner_cpu = raw_smp_processor_id(); |
232 | lock->owner = current; |
233 | } |
234 | |
235 | static inline void debug_write_unlock(rwlock_t *lock) |
236 | { |
237 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); |
238 | RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner"); |
239 | RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), |
240 | lock, "wrong CPU"); |
241 | lock->owner = SPINLOCK_OWNER_INIT; |
242 | lock->owner_cpu = -1; |
243 | } |
244 | |
245 | #if 0 /* This can cause lockups */ |
246 | static void __write_lock_debug(rwlock_t *lock) |
247 | { |
248 | u64 i; |
249 | u64 loops = loops_per_jiffy * HZ; |
250 | int print_once = 1; |
251 | |
252 | for (;;) { |
253 | for (i = 0; i < loops; i++) { |
254 | if (__raw_write_trylock(&lock->raw_lock)) |
255 | return; |
256 | __delay(1); |
257 | } |
258 | /* lockup suspected: */ |
259 | if (print_once) { |
260 | print_once = 0; |
261 | printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, " |
262 | "%s/%d, %p\n", |
263 | raw_smp_processor_id(), current->comm, |
264 | current->pid, lock); |
265 | dump_stack(); |
266 | } |
267 | } |
268 | } |
269 | #endif |
270 | |
271 | void _raw_write_lock(rwlock_t *lock) |
272 | { |
273 | debug_write_lock_before(lock); |
274 | __raw_write_lock(&lock->raw_lock); |
275 | debug_write_lock_after(lock); |
276 | } |
277 | |
278 | int _raw_write_trylock(rwlock_t *lock) |
279 | { |
280 | int ret = __raw_write_trylock(&lock->raw_lock); |
281 | |
282 | if (ret) |
283 | debug_write_lock_after(lock); |
284 | #ifndef CONFIG_SMP |
285 | /* |
286 | * Must not happen on UP: |
287 | */ |
288 | RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); |
289 | #endif |
290 | return ret; |
291 | } |
292 | |
293 | void _raw_write_unlock(rwlock_t *lock) |
294 | { |
295 | debug_write_unlock(lock); |
296 | __raw_write_unlock(&lock->raw_lock); |
297 | } |
298 |
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