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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/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
111 for (i = 0; i < loops; i++) {
112 if (arch_spin_trylock(&lock->raw_lock))
113 return;
114 __delay(1);
115 }
116 /* lockup suspected: */
117 spin_dump(lock, "lockup suspected");
118#ifdef CONFIG_SMP
119 trigger_all_cpu_backtrace();
120#endif
121
122 /*
123 * The trylock above was causing a livelock. Give the lower level arch
124 * specific lock code a chance to acquire the lock. We have already
125 * printed a warning/backtrace at this point. The non-debug arch
126 * specific code might actually succeed in acquiring the lock. If it is
127 * not successful, the end-result is the same - there is no forward
128 * progress.
129 */
130 arch_spin_lock(&lock->raw_lock);
131}
132
133void do_raw_spin_lock(raw_spinlock_t *lock)
134{
135 debug_spin_lock_before(lock);
136 if (unlikely(!arch_spin_trylock(&lock->raw_lock)))
137 __spin_lock_debug(lock);
138 debug_spin_lock_after(lock);
139}
140
141int do_raw_spin_trylock(raw_spinlock_t *lock)
142{
143 int ret = arch_spin_trylock(&lock->raw_lock);
144
145 if (ret)
146 debug_spin_lock_after(lock);
147#ifndef CONFIG_SMP
148 /*
149 * Must not happen on UP:
150 */
151 SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
152#endif
153 return ret;
154}
155
156void do_raw_spin_unlock(raw_spinlock_t *lock)
157{
158 debug_spin_unlock(lock);
159 arch_spin_unlock(&lock->raw_lock);
160}
161
162static void rwlock_bug(rwlock_t *lock, const char *msg)
163{
164 if (!debug_locks_off())
165 return;
166
167 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
168 msg, raw_smp_processor_id(), current->comm,
169 task_pid_nr(current), lock);
170 dump_stack();
171}
172
173#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
174
175#if 0 /* __write_lock_debug() can lock up - maybe this can too? */
176static void __read_lock_debug(rwlock_t *lock)
177{
178 u64 i;
179 u64 loops = loops_per_jiffy * HZ;
180 int print_once = 1;
181
182 for (;;) {
183 for (i = 0; i < loops; i++) {
184 if (arch_read_trylock(&lock->raw_lock))
185 return;
186 __delay(1);
187 }
188 /* lockup suspected: */
189 if (print_once) {
190 print_once = 0;
191 printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
192 "%s/%d, %p\n",
193 raw_smp_processor_id(), current->comm,
194 current->pid, lock);
195 dump_stack();
196 }
197 }
198}
199#endif
200
201void do_raw_read_lock(rwlock_t *lock)
202{
203 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
204 arch_read_lock(&lock->raw_lock);
205}
206
207int do_raw_read_trylock(rwlock_t *lock)
208{
209 int ret = arch_read_trylock(&lock->raw_lock);
210
211#ifndef CONFIG_SMP
212 /*
213 * Must not happen on UP:
214 */
215 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
216#endif
217 return ret;
218}
219
220void do_raw_read_unlock(rwlock_t *lock)
221{
222 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
223 arch_read_unlock(&lock->raw_lock);
224}
225
226static inline void debug_write_lock_before(rwlock_t *lock)
227{
228 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
229 RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
230 RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
231 lock, "cpu recursion");
232}
233
234static inline void debug_write_lock_after(rwlock_t *lock)
235{
236 lock->owner_cpu = raw_smp_processor_id();
237 lock->owner = current;
238}
239
240static inline void debug_write_unlock(rwlock_t *lock)
241{
242 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
243 RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
244 RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
245 lock, "wrong CPU");
246 lock->owner = SPINLOCK_OWNER_INIT;
247 lock->owner_cpu = -1;
248}
249
250#if 0 /* This can cause lockups */
251static void __write_lock_debug(rwlock_t *lock)
252{
253 u64 i;
254 u64 loops = loops_per_jiffy * HZ;
255 int print_once = 1;
256
257 for (;;) {
258 for (i = 0; i < loops; i++) {
259 if (arch_write_trylock(&lock->raw_lock))
260 return;
261 __delay(1);
262 }
263 /* lockup suspected: */
264 if (print_once) {
265 print_once = 0;
266 printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
267 "%s/%d, %p\n",
268 raw_smp_processor_id(), current->comm,
269 current->pid, lock);
270 dump_stack();
271 }
272 }
273}
274#endif
275
276void do_raw_write_lock(rwlock_t *lock)
277{
278 debug_write_lock_before(lock);
279 arch_write_lock(&lock->raw_lock);
280 debug_write_lock_after(lock);
281}
282
283int do_raw_write_trylock(rwlock_t *lock)
284{
285 int ret = arch_write_trylock(&lock->raw_lock);
286
287 if (ret)
288 debug_write_lock_after(lock);
289#ifndef CONFIG_SMP
290 /*
291 * Must not happen on UP:
292 */
293 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
294#endif
295 return ret;
296}
297
298void do_raw_write_unlock(rwlock_t *lock)
299{
300 debug_write_unlock(lock);
301 arch_write_unlock(&lock->raw_lock);
302}
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 mmiowb_spin_lock();
115 debug_spin_lock_after(lock);
116}
117
118int do_raw_spin_trylock(raw_spinlock_t *lock)
119{
120 int ret = arch_spin_trylock(&lock->raw_lock);
121
122 if (ret) {
123 mmiowb_spin_lock();
124 debug_spin_lock_after(lock);
125 }
126#ifndef CONFIG_SMP
127 /*
128 * Must not happen on UP:
129 */
130 SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
131#endif
132 return ret;
133}
134
135void do_raw_spin_unlock(raw_spinlock_t *lock)
136{
137 mmiowb_spin_unlock();
138 debug_spin_unlock(lock);
139 arch_spin_unlock(&lock->raw_lock);
140}
141
142static void rwlock_bug(rwlock_t *lock, const char *msg)
143{
144 if (!debug_locks_off())
145 return;
146
147 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
148 msg, raw_smp_processor_id(), current->comm,
149 task_pid_nr(current), lock);
150 dump_stack();
151}
152
153#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
154
155void do_raw_read_lock(rwlock_t *lock)
156{
157 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
158 arch_read_lock(&lock->raw_lock);
159}
160
161int do_raw_read_trylock(rwlock_t *lock)
162{
163 int ret = arch_read_trylock(&lock->raw_lock);
164
165#ifndef CONFIG_SMP
166 /*
167 * Must not happen on UP:
168 */
169 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
170#endif
171 return ret;
172}
173
174void do_raw_read_unlock(rwlock_t *lock)
175{
176 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
177 arch_read_unlock(&lock->raw_lock);
178}
179
180static inline void debug_write_lock_before(rwlock_t *lock)
181{
182 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
183 RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
184 RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
185 lock, "cpu recursion");
186}
187
188static inline void debug_write_lock_after(rwlock_t *lock)
189{
190 lock->owner_cpu = raw_smp_processor_id();
191 lock->owner = current;
192}
193
194static inline void debug_write_unlock(rwlock_t *lock)
195{
196 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
197 RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
198 RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
199 lock, "wrong CPU");
200 lock->owner = SPINLOCK_OWNER_INIT;
201 lock->owner_cpu = -1;
202}
203
204void do_raw_write_lock(rwlock_t *lock)
205{
206 debug_write_lock_before(lock);
207 arch_write_lock(&lock->raw_lock);
208 debug_write_lock_after(lock);
209}
210
211int do_raw_write_trylock(rwlock_t *lock)
212{
213 int ret = arch_write_trylock(&lock->raw_lock);
214
215 if (ret)
216 debug_write_lock_after(lock);
217#ifndef CONFIG_SMP
218 /*
219 * Must not happen on UP:
220 */
221 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
222#endif
223 return ret;
224}
225
226void do_raw_write_unlock(rwlock_t *lock)
227{
228 debug_write_unlock(lock);
229 arch_write_unlock(&lock->raw_lock);
230}