projects/linux·blob v3.5-rc6 · refs

298 lines · 6.8 KiB

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/export.h>
15
16void __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
32EXPORT_SYMBOL(__raw_spin_lock_init);
33
34void __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
50EXPORT_SYMBOL(__rwlock_init);
51
52static 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: %ps, .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
70static 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
80static inline void
81debug_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
89static 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
95static 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
106static 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 suspected");
122#ifdef CONFIG_SMP
123 trigger_all_cpu_backtrace();
124#endif
125 }
126 }
127}
128
129void 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
137int 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
152void do_raw_spin_unlock(raw_spinlock_t *lock)
153{
154 debug_spin_unlock(lock);
155 arch_spin_unlock(&lock->raw_lock);
156}
157
158static 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? */
172static 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
197void 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
203int 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
216void 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
222static 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
230static inline void debug_write_lock_after(rwlock_t *lock)
231{
232 lock->owner_cpu = raw_smp_processor_id();
233 lock->owner = current;
234}
235
236static 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 */
247static 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
272void 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
279int 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
294void do_raw_write_unlock(rwlock_t *lock)
295{
296 debug_write_unlock(lock);
297 arch_write_unlock(&lock->raw_lock);
298}