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