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[glibc.git] / ports / sysdeps / unix / sysv / linux / arm / nptl / lowlevellock.h
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1 /* Copyright (C) 2005-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library. If not, see
16 <http://www.gnu.org/licenses/>. */
17
18 #ifndef _LOWLEVELLOCK_H
19 #define _LOWLEVELLOCK_H 1
20
21 #include <time.h>
22 #include <sys/param.h>
23 #include <bits/pthreadtypes.h>
24 #include <atomic.h>
25 #include <sysdep.h>
26 #include <kernel-features.h>
27
28 #define FUTEX_WAIT 0
29 #define FUTEX_WAKE 1
30 #define FUTEX_REQUEUE 3
31 #define FUTEX_CMP_REQUEUE 4
32 #define FUTEX_WAKE_OP 5
33 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
34 #define FUTEX_LOCK_PI 6
35 #define FUTEX_UNLOCK_PI 7
36 #define FUTEX_TRYLOCK_PI 8
37 #define FUTEX_WAIT_BITSET 9
38 #define FUTEX_WAKE_BITSET 10
39 #define FUTEX_WAIT_REQUEUE_PI 11
40 #define FUTEX_CMP_REQUEUE_PI 12
41 #define FUTEX_PRIVATE_FLAG 128
42 #define FUTEX_CLOCK_REALTIME 256
43
44 #define FUTEX_BITSET_MATCH_ANY 0xffffffff
45
46 /* Values for 'private' parameter of locking macros. Yes, the
47 definition seems to be backwards. But it is not. The bit will be
48 reversed before passing to the system call. */
49 #define LLL_PRIVATE 0
50 #define LLL_SHARED FUTEX_PRIVATE_FLAG
51
52
53 #if !defined NOT_IN_libc || defined IS_IN_rtld
54 /* In libc.so or ld.so all futexes are private. */
55 # ifdef __ASSUME_PRIVATE_FUTEX
56 # define __lll_private_flag(fl, private) \
57 ((fl) | FUTEX_PRIVATE_FLAG)
58 # else
59 # define __lll_private_flag(fl, private) \
60 ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
61 # endif
62 #else
63 # ifdef __ASSUME_PRIVATE_FUTEX
64 # define __lll_private_flag(fl, private) \
65 (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
66 # else
67 # define __lll_private_flag(fl, private) \
68 (__builtin_constant_p (private) \
69 ? ((private) == 0 \
70 ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
71 : (fl)) \
72 : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
73 & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
74 # endif
75 #endif
76
77
78 #define lll_futex_wait(futexp, val, private) \
79 lll_futex_timed_wait(futexp, val, NULL, private)
80
81 #define lll_futex_timed_wait(futexp, val, timespec, private) \
82 ({ \
83 INTERNAL_SYSCALL_DECL (__err); \
84 long int __ret; \
85 __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
86 __lll_private_flag (FUTEX_WAIT, private), \
87 (val), (timespec)); \
88 __ret; \
89 })
90
91 #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
92 ({ \
93 INTERNAL_SYSCALL_DECL (__err); \
94 long int __ret; \
95 int __op = FUTEX_WAIT_BITSET | clockbit; \
96 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
97 __lll_private_flag (__op, private), \
98 (val), (timespec), NULL /* Unused. */, \
99 FUTEX_BITSET_MATCH_ANY); \
100 __ret; \
101 })
102
103 #define lll_futex_wake(futexp, nr, private) \
104 ({ \
105 INTERNAL_SYSCALL_DECL (__err); \
106 long int __ret; \
107 __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
108 __lll_private_flag (FUTEX_WAKE, private), \
109 (nr), 0); \
110 __ret; \
111 })
112
113 #define lll_robust_dead(futexv, private) \
114 do \
115 { \
116 int *__futexp = &(futexv); \
117 atomic_or (__futexp, FUTEX_OWNER_DIED); \
118 lll_futex_wake (__futexp, 1, private); \
119 } \
120 while (0)
121
122 /* Returns non-zero if error happened, zero if success. */
123 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
124 ({ \
125 INTERNAL_SYSCALL_DECL (__err); \
126 long int __ret; \
127 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
128 __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
129 (nr_wake), (nr_move), (mutex), (val)); \
130 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
131 })
132
133
134 /* Returns non-zero if error happened, zero if success. */
135 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
136 ({ \
137 INTERNAL_SYSCALL_DECL (__err); \
138 long int __ret; \
139 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
140 __lll_private_flag (FUTEX_WAKE_OP, private), \
141 (nr_wake), (nr_wake2), (futexp2), \
142 FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
143 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
144 })
145
146 /* Priority Inheritance support. */
147 #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
148 lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
149
150 #define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \
151 mutex, private) \
152 ({ \
153 INTERNAL_SYSCALL_DECL (__err); \
154 int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
155 \
156 INTERNAL_SYSCALL (futex, __err, 5, (futexp), \
157 __lll_private_flag (__op, private), \
158 (val), (timespec), mutex); \
159 })
160
161 #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
162 ({ \
163 INTERNAL_SYSCALL_DECL (__err); \
164 long int __ret; \
165 \
166 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
167 __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
168 (nr_wake), (nr_move), (mutex), (val)); \
169 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
170 })
171
172
173 #define lll_trylock(lock) \
174 atomic_compare_and_exchange_val_acq(&(lock), 1, 0)
175
176 #define lll_cond_trylock(lock) \
177 atomic_compare_and_exchange_val_acq(&(lock), 2, 0)
178
179 #define __lll_robust_trylock(futex, id) \
180 (atomic_compare_and_exchange_val_acq (futex, id, 0) != 0)
181 #define lll_robust_trylock(lock, id) \
182 __lll_robust_trylock (&(lock), id)
183
184 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
185 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
186 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
187
188 #define __lll_lock(futex, private) \
189 ((void) ({ \
190 int *__futex = (futex); \
191 if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, \
192 1, 0), 0)) \
193 { \
194 if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
195 __lll_lock_wait_private (__futex); \
196 else \
197 __lll_lock_wait (__futex, private); \
198 } \
199 }))
200 #define lll_lock(futex, private) __lll_lock (&(futex), private)
201
202
203 #define __lll_robust_lock(futex, id, private) \
204 ({ \
205 int *__futex = (futex); \
206 int __val = 0; \
207 \
208 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
209 0), 0)) \
210 __val = __lll_robust_lock_wait (__futex, private); \
211 __val; \
212 })
213 #define lll_robust_lock(futex, id, private) \
214 __lll_robust_lock (&(futex), id, private)
215
216
217 #define __lll_cond_lock(futex, private) \
218 ((void) ({ \
219 int *__futex = (futex); \
220 if (__builtin_expect (atomic_exchange_acq (__futex, 2), 0)) \
221 __lll_lock_wait (__futex, private); \
222 }))
223 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
224
225
226 #define lll_robust_cond_lock(futex, id, private) \
227 __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
228
229
230 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
231 int private) attribute_hidden;
232 extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
233 int private) attribute_hidden;
234
235 #define __lll_timedlock(futex, abstime, private) \
236 ({ \
237 int *__futex = (futex); \
238 int __val = 0; \
239 \
240 if (__builtin_expect (atomic_exchange_acq (__futex, 1), 0)) \
241 __val = __lll_timedlock_wait (__futex, abstime, private); \
242 __val; \
243 })
244 #define lll_timedlock(futex, abstime, private) \
245 __lll_timedlock (&(futex), abstime, private)
246
247
248 #define __lll_robust_timedlock(futex, abstime, id, private) \
249 ({ \
250 int *__futex = (futex); \
251 int __val = 0; \
252 \
253 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
254 0), 0)) \
255 __val = __lll_robust_timedlock_wait (__futex, abstime, private); \
256 __val; \
257 })
258 #define lll_robust_timedlock(futex, abstime, id, private) \
259 __lll_robust_timedlock (&(futex), abstime, id, private)
260
261
262 #define __lll_unlock(futex, private) \
263 (void) \
264 ({ int *__futex = (futex); \
265 int __oldval = atomic_exchange_rel (__futex, 0); \
266 if (__builtin_expect (__oldval > 1, 0)) \
267 lll_futex_wake (__futex, 1, private); \
268 })
269 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
270
271
272 #define __lll_robust_unlock(futex, private) \
273 (void) \
274 ({ int *__futex = (futex); \
275 int __oldval = atomic_exchange_rel (__futex, 0); \
276 if (__builtin_expect (__oldval & FUTEX_WAITERS, 0)) \
277 lll_futex_wake (__futex, 1, private); \
278 })
279 #define lll_robust_unlock(futex, private) \
280 __lll_robust_unlock(&(futex), private)
281
282
283 #define lll_islocked(futex) \
284 (futex != 0)
285
286
287 /* Our internal lock implementation is identical to the binary-compatible
288 mutex implementation. */
289
290 /* Initializers for lock. */
291 #define LLL_LOCK_INITIALIZER (0)
292 #define LLL_LOCK_INITIALIZER_LOCKED (1)
293
294 /* The states of a lock are:
295 0 - untaken
296 1 - taken by one user
297 >1 - taken by more users */
298
299 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
300 wakeup when the clone terminates. The memory location contains the
301 thread ID while the clone is running and is reset to zero
302 afterwards. */
303 #define lll_wait_tid(tid) \
304 do { \
305 __typeof (tid) __tid; \
306 while ((__tid = (tid)) != 0) \
307 lll_futex_wait (&(tid), __tid, LLL_SHARED);\
308 } while (0)
309
310 extern int __lll_timedwait_tid (int *, const struct timespec *)
311 attribute_hidden;
312
313 #define lll_timedwait_tid(tid, abstime) \
314 ({ \
315 int __res = 0; \
316 if ((tid) != 0) \
317 __res = __lll_timedwait_tid (&(tid), (abstime)); \
318 __res; \
319 })
320
321 #endif /* lowlevellock.h */
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