Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux-2.6-microblaze.git] / kernel / locking / spinlock_debug.c
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
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: %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
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 /*
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  */
110 void 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
117 int 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
132 void do_raw_spin_unlock(raw_spinlock_t *lock)
133 {
134         debug_spin_unlock(lock);
135         arch_spin_unlock(&lock->raw_lock);
136 }
137
138 static 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
151 void 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
157 int 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
170 void 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
176 static 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
184 static inline void debug_write_lock_after(rwlock_t *lock)
185 {
186         lock->owner_cpu = raw_smp_processor_id();
187         lock->owner = current;
188 }
189
190 static 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
200 void 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
207 int 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
222 void do_raw_write_unlock(rwlock_t *lock)
223 {
224         debug_write_unlock(lock);
225         arch_write_unlock(&lock->raw_lock);
226 }