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fb1c8f93 IM |
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 | ||
fb1c8f93 IM |
9 | #include <linux/spinlock.h> |
10 | #include <linux/interrupt.h> | |
9a11b49a | 11 | #include <linux/debug_locks.h> |
fb1c8f93 | 12 | #include <linux/delay.h> |
9a11b49a | 13 | #include <linux/module.h> |
fb1c8f93 | 14 | |
8a25d5de IM |
15 | void __spin_lock_init(spinlock_t *lock, const char *name, |
16 | struct lock_class_key *key) | |
17 | { | |
18 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
19 | /* | |
20 | * Make sure we are not reinitializing a held lock: | |
21 | */ | |
22 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); | |
23 | lockdep_init_map(&lock->dep_map, name, key); | |
24 | #endif | |
25 | lock->raw_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED; | |
26 | lock->magic = SPINLOCK_MAGIC; | |
27 | lock->owner = SPINLOCK_OWNER_INIT; | |
28 | lock->owner_cpu = -1; | |
29 | } | |
30 | ||
31 | EXPORT_SYMBOL(__spin_lock_init); | |
32 | ||
33 | void __rwlock_init(rwlock_t *lock, const char *name, | |
34 | struct lock_class_key *key) | |
35 | { | |
36 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
37 | /* | |
38 | * Make sure we are not reinitializing a held lock: | |
39 | */ | |
40 | debug_check_no_locks_freed((void *)lock, sizeof(*lock)); | |
41 | lockdep_init_map(&lock->dep_map, name, key); | |
42 | #endif | |
43 | lock->raw_lock = (raw_rwlock_t) __RAW_RW_LOCK_UNLOCKED; | |
44 | lock->magic = RWLOCK_MAGIC; | |
45 | lock->owner = SPINLOCK_OWNER_INIT; | |
46 | lock->owner_cpu = -1; | |
47 | } | |
48 | ||
49 | EXPORT_SYMBOL(__rwlock_init); | |
50 | ||
fb1c8f93 IM |
51 | static void spin_bug(spinlock_t *lock, const char *msg) |
52 | { | |
fb1c8f93 IM |
53 | struct task_struct *owner = NULL; |
54 | ||
9a11b49a IM |
55 | if (!debug_locks_off()) |
56 | return; | |
57 | ||
58 | if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT) | |
59 | owner = lock->owner; | |
60 | printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n", | |
61 | msg, raw_smp_processor_id(), | |
62 | current->comm, current->pid); | |
63 | printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, " | |
64 | ".owner_cpu: %d\n", | |
65 | lock, lock->magic, | |
66 | owner ? owner->comm : "<none>", | |
67 | owner ? owner->pid : -1, | |
68 | lock->owner_cpu); | |
69 | dump_stack(); | |
fb1c8f93 IM |
70 | } |
71 | ||
72 | #define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg) | |
73 | ||
9a11b49a IM |
74 | static inline void |
75 | debug_spin_lock_before(spinlock_t *lock) | |
fb1c8f93 IM |
76 | { |
77 | SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); | |
78 | SPIN_BUG_ON(lock->owner == current, lock, "recursion"); | |
79 | SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), | |
80 | lock, "cpu recursion"); | |
81 | } | |
82 | ||
83 | static inline void debug_spin_lock_after(spinlock_t *lock) | |
84 | { | |
85 | lock->owner_cpu = raw_smp_processor_id(); | |
86 | lock->owner = current; | |
87 | } | |
88 | ||
89 | static inline void debug_spin_unlock(spinlock_t *lock) | |
90 | { | |
91 | SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic"); | |
92 | SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked"); | |
93 | SPIN_BUG_ON(lock->owner != current, lock, "wrong owner"); | |
94 | SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), | |
95 | lock, "wrong CPU"); | |
96 | lock->owner = SPINLOCK_OWNER_INIT; | |
97 | lock->owner_cpu = -1; | |
98 | } | |
99 | ||
100 | static void __spin_lock_debug(spinlock_t *lock) | |
101 | { | |
102 | int print_once = 1; | |
103 | u64 i; | |
104 | ||
105 | for (;;) { | |
106 | for (i = 0; i < loops_per_jiffy * HZ; i++) { | |
fb1c8f93 IM |
107 | if (__raw_spin_trylock(&lock->raw_lock)) |
108 | return; | |
e0a60296 | 109 | __delay(1); |
fb1c8f93 IM |
110 | } |
111 | /* lockup suspected: */ | |
112 | if (print_once) { | |
113 | print_once = 0; | |
51989b9f DJ |
114 | printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, " |
115 | "%s/%d, %p\n", | |
bb44f116 IM |
116 | raw_smp_processor_id(), current->comm, |
117 | current->pid, lock); | |
fb1c8f93 IM |
118 | dump_stack(); |
119 | } | |
120 | } | |
121 | } | |
122 | ||
123 | void _raw_spin_lock(spinlock_t *lock) | |
124 | { | |
125 | debug_spin_lock_before(lock); | |
126 | if (unlikely(!__raw_spin_trylock(&lock->raw_lock))) | |
127 | __spin_lock_debug(lock); | |
128 | debug_spin_lock_after(lock); | |
129 | } | |
130 | ||
131 | int _raw_spin_trylock(spinlock_t *lock) | |
132 | { | |
133 | int ret = __raw_spin_trylock(&lock->raw_lock); | |
134 | ||
135 | if (ret) | |
136 | debug_spin_lock_after(lock); | |
137 | #ifndef CONFIG_SMP | |
138 | /* | |
139 | * Must not happen on UP: | |
140 | */ | |
141 | SPIN_BUG_ON(!ret, lock, "trylock failure on UP"); | |
142 | #endif | |
143 | return ret; | |
144 | } | |
145 | ||
146 | void _raw_spin_unlock(spinlock_t *lock) | |
147 | { | |
148 | debug_spin_unlock(lock); | |
149 | __raw_spin_unlock(&lock->raw_lock); | |
150 | } | |
151 | ||
152 | static void rwlock_bug(rwlock_t *lock, const char *msg) | |
153 | { | |
9a11b49a IM |
154 | if (!debug_locks_off()) |
155 | return; | |
156 | ||
157 | printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n", | |
158 | msg, raw_smp_processor_id(), current->comm, | |
159 | current->pid, lock); | |
160 | dump_stack(); | |
fb1c8f93 IM |
161 | } |
162 | ||
163 | #define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg) | |
164 | ||
72f0b4e2 | 165 | #if 0 /* __write_lock_debug() can lock up - maybe this can too? */ |
fb1c8f93 IM |
166 | static void __read_lock_debug(rwlock_t *lock) |
167 | { | |
168 | int print_once = 1; | |
169 | u64 i; | |
170 | ||
171 | for (;;) { | |
172 | for (i = 0; i < loops_per_jiffy * HZ; i++) { | |
fb1c8f93 IM |
173 | if (__raw_read_trylock(&lock->raw_lock)) |
174 | return; | |
e0a60296 | 175 | __delay(1); |
fb1c8f93 IM |
176 | } |
177 | /* lockup suspected: */ | |
178 | if (print_once) { | |
179 | print_once = 0; | |
51989b9f DJ |
180 | printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, " |
181 | "%s/%d, %p\n", | |
bb44f116 IM |
182 | raw_smp_processor_id(), current->comm, |
183 | current->pid, lock); | |
fb1c8f93 IM |
184 | dump_stack(); |
185 | } | |
186 | } | |
187 | } | |
72f0b4e2 | 188 | #endif |
fb1c8f93 IM |
189 | |
190 | void _raw_read_lock(rwlock_t *lock) | |
191 | { | |
192 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
72f0b4e2 | 193 | __raw_read_lock(&lock->raw_lock); |
fb1c8f93 IM |
194 | } |
195 | ||
196 | int _raw_read_trylock(rwlock_t *lock) | |
197 | { | |
198 | int ret = __raw_read_trylock(&lock->raw_lock); | |
199 | ||
200 | #ifndef CONFIG_SMP | |
201 | /* | |
202 | * Must not happen on UP: | |
203 | */ | |
204 | RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); | |
205 | #endif | |
206 | return ret; | |
207 | } | |
208 | ||
209 | void _raw_read_unlock(rwlock_t *lock) | |
210 | { | |
211 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
212 | __raw_read_unlock(&lock->raw_lock); | |
213 | } | |
214 | ||
215 | static inline void debug_write_lock_before(rwlock_t *lock) | |
216 | { | |
217 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
218 | RWLOCK_BUG_ON(lock->owner == current, lock, "recursion"); | |
219 | RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(), | |
220 | lock, "cpu recursion"); | |
221 | } | |
222 | ||
223 | static inline void debug_write_lock_after(rwlock_t *lock) | |
224 | { | |
225 | lock->owner_cpu = raw_smp_processor_id(); | |
226 | lock->owner = current; | |
227 | } | |
228 | ||
229 | static inline void debug_write_unlock(rwlock_t *lock) | |
230 | { | |
231 | RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic"); | |
232 | RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner"); | |
233 | RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(), | |
234 | lock, "wrong CPU"); | |
235 | lock->owner = SPINLOCK_OWNER_INIT; | |
236 | lock->owner_cpu = -1; | |
237 | } | |
238 | ||
72f0b4e2 | 239 | #if 0 /* This can cause lockups */ |
fb1c8f93 IM |
240 | static void __write_lock_debug(rwlock_t *lock) |
241 | { | |
242 | int print_once = 1; | |
243 | u64 i; | |
244 | ||
245 | for (;;) { | |
246 | for (i = 0; i < loops_per_jiffy * HZ; i++) { | |
fb1c8f93 IM |
247 | if (__raw_write_trylock(&lock->raw_lock)) |
248 | return; | |
e0a60296 | 249 | __delay(1); |
fb1c8f93 IM |
250 | } |
251 | /* lockup suspected: */ | |
252 | if (print_once) { | |
253 | print_once = 0; | |
51989b9f DJ |
254 | printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, " |
255 | "%s/%d, %p\n", | |
bb44f116 IM |
256 | raw_smp_processor_id(), current->comm, |
257 | current->pid, lock); | |
fb1c8f93 IM |
258 | dump_stack(); |
259 | } | |
260 | } | |
261 | } | |
72f0b4e2 | 262 | #endif |
fb1c8f93 IM |
263 | |
264 | void _raw_write_lock(rwlock_t *lock) | |
265 | { | |
266 | debug_write_lock_before(lock); | |
72f0b4e2 | 267 | __raw_write_lock(&lock->raw_lock); |
fb1c8f93 IM |
268 | debug_write_lock_after(lock); |
269 | } | |
270 | ||
271 | int _raw_write_trylock(rwlock_t *lock) | |
272 | { | |
273 | int ret = __raw_write_trylock(&lock->raw_lock); | |
274 | ||
275 | if (ret) | |
276 | debug_write_lock_after(lock); | |
277 | #ifndef CONFIG_SMP | |
278 | /* | |
279 | * Must not happen on UP: | |
280 | */ | |
281 | RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP"); | |
282 | #endif | |
283 | return ret; | |
284 | } | |
285 | ||
286 | void _raw_write_unlock(rwlock_t *lock) | |
287 | { | |
288 | debug_write_unlock(lock); | |
289 | __raw_write_unlock(&lock->raw_lock); | |
290 | } |