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 | |
17 | void __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(from: (void *)lock, len: sizeof(*lock)); |
25 | lockdep_init_map_wait(lock: &lock->dep_map, name, key, subclass: 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 | |
33 | EXPORT_SYMBOL(__raw_spin_lock_init); |
34 | |
35 | #ifndef CONFIG_PREEMPT_RT |
36 | void __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(from: (void *)lock, len: sizeof(*lock)); |
44 | lockdep_init_map_wait(lock: &lock->dep_map, name, key, subclass: 0, inner: 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 | |
52 | EXPORT_SYMBOL(__rwlock_init); |
53 | #endif |
54 | |
55 | static 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 | |
73 | static 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 | |
83 | static inline void |
84 | debug_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 | |
92 | static 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 | |
98 | static 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 | */ |
113 | void 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 | |
121 | int 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 | |
138 | void 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 |
146 | static 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 | |
159 | void 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 | |
165 | int 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 | |
178 | void 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 | |
184 | static 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 | |
192 | static 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 | |
198 | static 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 | |
208 | void 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 | |
215 | int 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 | |
230 | void 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 */ |
237 | |