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[glibc.git] / sysdeps / unix / sysv / linux / mips / nptl / lowlevellock.h
blob88b601eadd06118f8ebcd636d6997e4ef19cade7
1 /* Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008,
2 2009 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library. If not, see
17 <http://www.gnu.org/licenses/>. */
18
19 #ifndef _LOWLEVELLOCK_H
20 #define _LOWLEVELLOCK_H 1
21
22 #include <time.h>
23 #include <sys/param.h>
24 #include <bits/pthreadtypes.h>
25 #include <atomic.h>
26 #include <sysdep.h>
27 #include <kernel-features.h>
28
29 #define FUTEX_WAIT 0
30 #define FUTEX_WAKE 1
31 #define FUTEX_REQUEUE 3
32 #define FUTEX_CMP_REQUEUE 4
33 #define FUTEX_WAKE_OP 5
34 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
35 #define FUTEX_LOCK_PI 6
36 #define FUTEX_UNLOCK_PI 7
37 #define FUTEX_TRYLOCK_PI 8
38 #define FUTEX_WAIT_BITSET 9
39 #define FUTEX_WAKE_BITSET 10
40 #define FUTEX_PRIVATE_FLAG 128
41 #define FUTEX_CLOCK_REALTIME 256
42
43 #define FUTEX_BITSET_MATCH_ANY 0xffffffff
44
45 /* Values for 'private' parameter of locking macros. Yes, the
46 definition seems to be backwards. But it is not. The bit will be
47 reversed before passing to the system call. */
48 #define LLL_PRIVATE 0
49 #define LLL_SHARED FUTEX_PRIVATE_FLAG
50
51
52 #if !defined NOT_IN_libc || defined IS_IN_rtld
53 /* In libc.so or ld.so all futexes are private. */
54 # ifdef __ASSUME_PRIVATE_FUTEX
55 # define __lll_private_flag(fl, private) \
56 ((fl) | FUTEX_PRIVATE_FLAG)
57 # else
58 # define __lll_private_flag(fl, private) \
59 ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
60 # endif
61 #else
62 # ifdef __ASSUME_PRIVATE_FUTEX
63 # define __lll_private_flag(fl, private) \
64 (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
65 # else
66 # define __lll_private_flag(fl, private) \
67 (__builtin_constant_p (private) \
68 ? ((private) == 0 \
69 ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
70 : (fl)) \
71 : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
72 & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
73 # endif
74 #endif
75
76
77 #define lll_futex_wait(futexp, val, private) \
78 lll_futex_timed_wait(futexp, val, NULL, private)
79
80 #define lll_futex_timed_wait(futexp, val, timespec, private) \
81 ({ \
82 INTERNAL_SYSCALL_DECL (__err); \
83 long int __ret; \
84 __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \
85 __lll_private_flag (FUTEX_WAIT, private), \
86 (val), (timespec)); \
87 INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
88 })
89
90 #define lll_futex_wake(futexp, nr, private) \
91 ({ \
92 INTERNAL_SYSCALL_DECL (__err); \
93 long int __ret; \
94 __ret = INTERNAL_SYSCALL (futex, __err, 4, (long) (futexp), \
95 __lll_private_flag (FUTEX_WAKE, private), \
96 (nr), 0); \
97 INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
98 })
99
100 #define lll_robust_dead(futexv, private) \
101 do \
102 { \
103 int *__futexp = &(futexv); \
104 atomic_or (__futexp, FUTEX_OWNER_DIED); \
105 lll_futex_wake (__futexp, 1, private); \
106 } \
107 while (0)
108
109 /* Returns non-zero if error happened, zero if success. */
110 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
111 ({ \
112 INTERNAL_SYSCALL_DECL (__err); \
113 long int __ret; \
114 __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp), \
115 __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
116 (nr_wake), (nr_move), (mutex), (val)); \
117 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
118 })
119
120 /* Returns non-zero if error happened, zero if success. */
121 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
122 ({ \
123 INTERNAL_SYSCALL_DECL (__err); \
124 long int __ret; \
125 \
126 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
127 __lll_private_flag (FUTEX_WAKE_OP, private), \
128 (nr_wake), (nr_wake2), (futexp2), \
129 FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
130 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
131 })
132
133 static inline int __attribute__((always_inline))
134 __lll_trylock(int *futex)
135 {
136 return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0;
137 }
138 #define lll_trylock(lock) __lll_trylock (&(lock))
139
140
141 static inline int __attribute__((always_inline))
142 __lll_cond_trylock(int *futex)
143 {
144 return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0;
145 }
146 #define lll_cond_trylock(lock) __lll_cond_trylock (&(lock))
147
148
149 static inline int __attribute__((always_inline))
150 __lll_robust_trylock(int *futex, int id)
151 {
152 return atomic_compare_and_exchange_val_acq (futex, id, 0) != 0;
153 }
154 #define lll_robust_trylock(lock, id) \
155 __lll_robust_trylock (&(lock), id)
156
157 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
158 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
159 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
160
161 #define __lll_lock(futex, private) \
162 ((void) ({ \
163 int *__futex = (futex); \
164 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, \
165 1, 0), 0)) \
166 { \
167 if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
168 __lll_lock_wait_private (__futex); \
169 else \
170 __lll_lock_wait (__futex, private); \
171 } \
172 }))
173 #define lll_lock(futex, private) __lll_lock (&(futex), private)
174
175
176 #define __lll_robust_lock(futex, id, private) \
177 ({ \
178 int *__futex = (futex); \
179 int __val = 0; \
180 \
181 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
182 0), 0)) \
183 __val = __lll_robust_lock_wait (__futex, private); \
184 __val; \
185 })
186 #define lll_robust_lock(futex, id, private) \
187 __lll_robust_lock (&(futex), id, private)
188
189
190 static inline void __attribute__ ((always_inline))
191 __lll_cond_lock (int *futex, int private)
192 {
193 if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
194 __lll_lock_wait (futex, private);
195 }
196 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
197
198
199 #define lll_robust_cond_lock(futex, id, private) \
200 __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
201
202
203 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
204 int private) attribute_hidden;
205 extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
206 int private) attribute_hidden;
207
208 static inline int __attribute__ ((always_inline))
209 __lll_timedlock (int *futex, const struct timespec *abstime, int private)
210 {
211 int result = 0;
212 if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
213 result = __lll_timedlock_wait (futex, abstime, private);
214 return result;
215 }
216 #define lll_timedlock(futex, abstime, private) \
217 __lll_timedlock (&(futex), abstime, private)
218
219
220 static inline int __attribute__ ((always_inline))
221 __lll_robust_timedlock (int *futex, const struct timespec *abstime,
222 int id, int private)
223 {
224 int result = 0;
225 if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
226 result = __lll_robust_timedlock_wait (futex, abstime, private);
227 return result;
228 }
229 #define lll_robust_timedlock(futex, abstime, id, private) \
230 __lll_robust_timedlock (&(futex), abstime, id, private)
231
232
233 #define __lll_unlock(futex, private) \
234 ((void) ({ \
235 int *__futex = (futex); \
236 int __val = atomic_exchange_rel (__futex, 0); \
237 \
238 if (__builtin_expect (__val > 1, 0)) \
239 lll_futex_wake (__futex, 1, private); \
240 }))
241 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
242
243
244 #define __lll_robust_unlock(futex, private) \
245 ((void) ({ \
246 int *__futex = (futex); \
247 int __val = atomic_exchange_rel (__futex, 0); \
248 \
249 if (__builtin_expect (__val & FUTEX_WAITERS, 0)) \
250 lll_futex_wake (__futex, 1, private); \
251 }))
252 #define lll_robust_unlock(futex, private) \
253 __lll_robust_unlock(&(futex), private)
254
255
256 #define lll_islocked(futex) \
257 (futex != 0)
258
259
260 /* Our internal lock implementation is identical to the binary-compatible
261 mutex implementation. */
262
263 /* Initializers for lock. */
264 #define LLL_LOCK_INITIALIZER (0)
265 #define LLL_LOCK_INITIALIZER_LOCKED (1)
266
267 /* The states of a lock are:
268 0 - untaken
269 1 - taken by one user
270 >1 - taken by more users */
271
272 /* The kernel notifies a process which uses CLONE_CLEARTID via futex
273 wakeup when the clone terminates. The memory location contains the
274 thread ID while the clone is running and is reset to zero
275 afterwards. */
276 #define lll_wait_tid(tid) \
277 do { \
278 __typeof (tid) __tid; \
279 while ((__tid = (tid)) != 0) \
280 lll_futex_wait (&(tid), __tid, LLL_SHARED); \
281 } while (0)
282
283 extern int __lll_timedwait_tid (int *, const struct timespec *)
284 attribute_hidden;
285
286 #define lll_timedwait_tid(tid, abstime) \
287 ({ \
288 int __res = 0; \
289 if ((tid) != 0) \
290 __res = __lll_timedwait_tid (&(tid), (abstime)); \
291 __res; \
292 })
293
294 #endif /* lowlevellock.h */
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