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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#include <linux/pid.h>
16
17void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,
18 struct lock_class_key *key, short inner)
19{
20#ifdef CONFIG_DEBUG_LOCK_ALLOC
21 /*
22 * Make sure we are not reinitializing a held lock:
23 */
24 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
25 lockdep_init_map_wait(&lock->dep_map, name, key, 0, inner);
26#endif
27 lock->raw_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;
28 lock->magic = SPINLOCK_MAGIC;
29 lock->owner = SPINLOCK_OWNER_INIT;
30 lock->owner_cpu = -1;
31}
32
33EXPORT_SYMBOL(__raw_spin_lock_init);
34
35#ifndef CONFIG_PREEMPT_RT
36void __rwlock_init(rwlock_t *lock, const char *name,
37 struct lock_class_key *key)
38{
39#ifdef CONFIG_DEBUG_LOCK_ALLOC
40 /*
41 * Make sure we are not reinitializing a held lock:
42 */
43 debug_check_no_locks_freed((void *)lock, sizeof(*lock));
44 lockdep_init_map_wait(&lock->dep_map, name, key, 0, LD_WAIT_CONFIG);
45#endif
46 lock->raw_lock = (arch_rwlock_t) __ARCH_RW_LOCK_UNLOCKED;
47 lock->magic = RWLOCK_MAGIC;
48 lock->owner = SPINLOCK_OWNER_INIT;
49 lock->owner_cpu = -1;
50}
51
52EXPORT_SYMBOL(__rwlock_init);
53#endif
54
55static void spin_dump(raw_spinlock_t *lock, const char *msg)
56{
57 struct task_struct *owner = READ_ONCE(lock->owner);
58
59 if (owner == SPINLOCK_OWNER_INIT)
60 owner = NULL;
61 printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
62 msg, raw_smp_processor_id(),
63 current->comm, task_pid_nr(current));
64 printk(KERN_EMERG " lock: %pS, .magic: %08x, .owner: %s/%d, "
65 ".owner_cpu: %d\n",
66 lock, READ_ONCE(lock->magic),
67 owner ? owner->comm : "<none>",
68 owner ? task_pid_nr(owner) : -1,
69 READ_ONCE(lock->owner_cpu));
70 dump_stack();
71}
72
73static void spin_bug(raw_spinlock_t *lock, const char *msg)
74{
75 if (!debug_locks_off())
76 return;
77
78 spin_dump(lock, msg);
79}
80
81#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
82
83static inline void
84debug_spin_lock_before(raw_spinlock_t *lock)
85{
86 SPIN_BUG_ON(READ_ONCE(lock->magic) != SPINLOCK_MAGIC, lock, "bad magic");
87 SPIN_BUG_ON(READ_ONCE(lock->owner) == current, lock, "recursion");
88 SPIN_BUG_ON(READ_ONCE(lock->owner_cpu) == raw_smp_processor_id(),
89 lock, "cpu recursion");
90}
91
92static inline void debug_spin_lock_after(raw_spinlock_t *lock)
93{
94 WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
95 WRITE_ONCE(lock->owner, current);
96}
97
98static inline void debug_spin_unlock(raw_spinlock_t *lock)
99{
100 SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
101 SPIN_BUG_ON(!raw_spin_is_locked(lock), lock, "already unlocked");
102 SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
103 SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
104 lock, "wrong CPU");
105 WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
106 WRITE_ONCE(lock->owner_cpu, -1);
107}
108
109/*
110 * We are now relying on the NMI watchdog to detect lockup instead of doing
111 * the detection here with an unfair lock which can cause problem of its own.
112 */
113void do_raw_spin_lock(raw_spinlock_t *lock)
114{
115 debug_spin_lock_before(lock);
116 arch_spin_lock(&lock->raw_lock);
117 mmiowb_spin_lock();
118 debug_spin_lock_after(lock);
119}
120
121int do_raw_spin_trylock(raw_spinlock_t *lock)
122{
123 int ret = arch_spin_trylock(&lock->raw_lock);
124
125 if (ret) {
126 mmiowb_spin_lock();
127 debug_spin_lock_after(lock);
128 }
129#ifndef CONFIG_SMP
130 /*
131 * Must not happen on UP:
132 */
133 SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
134#endif
135 return ret;
136}
137
138void do_raw_spin_unlock(raw_spinlock_t *lock)
139{
140 mmiowb_spin_unlock();
141 debug_spin_unlock(lock);
142 arch_spin_unlock(&lock->raw_lock);
143}
144
145#ifndef CONFIG_PREEMPT_RT
146static void rwlock_bug(rwlock_t *lock, const char *msg)
147{
148 if (!debug_locks_off())
149 return;
150
151 printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
152 msg, raw_smp_processor_id(), current->comm,
153 task_pid_nr(current), lock);
154 dump_stack();
155}
156
157#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
158
159void do_raw_read_lock(rwlock_t *lock)
160{
161 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
162 arch_read_lock(&lock->raw_lock);
163}
164
165int do_raw_read_trylock(rwlock_t *lock)
166{
167 int ret = arch_read_trylock(&lock->raw_lock);
168
169#ifndef CONFIG_SMP
170 /*
171 * Must not happen on UP:
172 */
173 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
174#endif
175 return ret;
176}
177
178void do_raw_read_unlock(rwlock_t *lock)
179{
180 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
181 arch_read_unlock(&lock->raw_lock);
182}
183
184static inline void debug_write_lock_before(rwlock_t *lock)
185{
186 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
187 RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
188 RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
189 lock, "cpu recursion");
190}
191
192static inline void debug_write_lock_after(rwlock_t *lock)
193{
194 WRITE_ONCE(lock->owner_cpu, raw_smp_processor_id());
195 WRITE_ONCE(lock->owner, current);
196}
197
198static inline void debug_write_unlock(rwlock_t *lock)
199{
200 RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
201 RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
202 RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
203 lock, "wrong CPU");
204 WRITE_ONCE(lock->owner, SPINLOCK_OWNER_INIT);
205 WRITE_ONCE(lock->owner_cpu, -1);
206}
207
208void do_raw_write_lock(rwlock_t *lock)
209{
210 debug_write_lock_before(lock);
211 arch_write_lock(&lock->raw_lock);
212 debug_write_lock_after(lock);
213}
214
215int do_raw_write_trylock(rwlock_t *lock)
216{
217 int ret = arch_write_trylock(&lock->raw_lock);
218
219 if (ret)
220 debug_write_lock_after(lock);
221#ifndef CONFIG_SMP
222 /*
223 * Must not happen on UP:
224 */
225 RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
226#endif
227 return ret;
228}
229
230void do_raw_write_unlock(rwlock_t *lock)
231{
232 debug_write_unlock(lock);
233 arch_write_unlock(&lock->raw_lock);
234}
235
236#endif /* !CONFIG_PREEMPT_RT */
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}