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