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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 | } |
299 |
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