projects/linux·blob eac61655 · refs

226 lines · 5.5 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
106/*
107 * We are now relying on the NMI watchdog to detect lockup instead of doing
108 * the detection here with an unfair lock which can cause problem of its own.
109 */
110void do_raw_spin_lock(raw_spinlock_t *lock)
111{
112 debug_spin_lock_before(lock);
113 arch_spin_lock(&lock->raw_lock);
114 debug_spin_lock_after(lock);
115}
116
117int do_raw_spin_trylock(raw_spinlock_t *lock)
118{
119 int ret = arch_spin_trylock(&lock->raw_lock);
120
121 if (ret)
122 debug_spin_lock_after(lock);
123#ifndef CONFIG_SMP
124 /*
125 * Must not happen on UP:
126 */
127 SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
128#endif
129 return ret;
130}
131
132void do_raw_spin_unlock(raw_spinlock_t *lock)
133{
134 debug_spin_unlock(lock);
135 arch_spin_unlock(&lock->raw_lock);
136}
137
138static void rwlock_bug(rwlock_t *lock, const char *msg)
139{
140 if (!debug_locks_off())
141 return;
142
143 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
144 msg, raw_smp_processor_id(), current->comm,
145 task_pid_nr(current), lock);
146 dump_stack();
147}
148
149#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
150
151void do_raw_read_lock(rwlock_t *lock)
152{
153 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
154 arch_read_lock(&lock->raw_lock);
155}
156
157int do_raw_read_trylock(rwlock_t *lock)
158{
159 int ret = arch_read_trylock(&lock->raw_lock);
160
161#ifndef CONFIG_SMP
162 /*
163 * Must not happen on UP:
164 */
165 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
166#endif
167 return ret;
168}
169
170void do_raw_read_unlock(rwlock_t *lock)
171{
172 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
173 arch_read_unlock(&lock->raw_lock);
174}
175
176static inline void debug_write_lock_before(rwlock_t *lock)
177{
178 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
179 RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
180 RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
181 lock, "cpu recursion");
182}
183
184static inline void debug_write_lock_after(rwlock_t *lock)
185{
186 lock->owner_cpu = raw_smp_processor_id();
187 lock->owner = current;
188}
189
190static inline void debug_write_unlock(rwlock_t *lock)
191{
192 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
193 RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
194 RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
195 lock, "wrong CPU");
196 lock->owner = SPINLOCK_OWNER_INIT;
197 lock->owner_cpu = -1;
198}
199
200void do_raw_write_lock(rwlock_t *lock)
201{
202 debug_write_lock_before(lock);
203 arch_write_lock(&lock->raw_lock);
204 debug_write_lock_after(lock);
205}
206
207int do_raw_write_trylock(rwlock_t *lock)
208{
209 int ret = arch_write_trylock(&lock->raw_lock);
210
211 if (ret)
212 debug_write_lock_after(lock);
213#ifndef CONFIG_SMP
214 /*
215 * Must not happen on UP:
216 */
217 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
218#endif
219 return ret;
220}
221
222void do_raw_write_unlock(rwlock_t *lock)
223{
224 debug_write_unlock(lock);
225 arch_write_unlock(&lock->raw_lock);
226}