1 /* Copyright (C) 2010-2014 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Maxim Kuvyrkov <maxim@codesourcery.com>, 2010.
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.
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.
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/>. */
19 /* Borrowed from ARM's version. */
21 #ifndef _LOWLEVELLOCK_H
22 #define _LOWLEVELLOCK_H 1
25 #include <sys/param.h>
26 #include <bits/pthreadtypes.h>
28 #include <kernel-features.h>
32 #define FUTEX_REQUEUE 3
33 #define FUTEX_CMP_REQUEUE 4
34 #define FUTEX_WAKE_OP 5
35 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
36 #define FUTEX_LOCK_PI 6
37 #define FUTEX_UNLOCK_PI 7
38 #define FUTEX_TRYLOCK_PI 8
39 #define FUTEX_WAIT_BITSET 9
40 #define FUTEX_WAKE_BITSET 10
41 #define FUTEX_WAIT_REQEUE_PI 11
42 #define FUTEX_CMP_REQEUE_PI 12
43 #define FUTEX_PRIVATE_FLAG 128
44 #define FUTEX_CLOCK_REALTIME 256
46 #define FUTEX_BITSET_MATCH_ANY 0xffffffff
48 /* Values for 'private' parameter of locking macros. Yes, the
49 definition seems to be backwards. But it is not. The bit will be
50 reversed before passing to the system call. */
52 #define LLL_SHARED FUTEX_PRIVATE_FLAG
55 #if !defined NOT_IN_libc || defined IS_IN_rtld
56 /* In libc.so or ld.so all futexes are private. */
57 # ifdef __ASSUME_PRIVATE_FUTEX
58 # define __lll_private_flag(fl, private) \
59 ((fl) | FUTEX_PRIVATE_FLAG)
61 # define __lll_private_flag(fl, private) \
62 ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
65 # ifdef __ASSUME_PRIVATE_FUTEX
66 # define __lll_private_flag(fl, private) \
67 (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
69 # define __lll_private_flag(fl, private) \
70 (__builtin_constant_p (private) \
72 ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
74 : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
75 & THREAD_GETMEM (THREAD_SELF, header.private_futex))))
80 #define lll_futex_wait(futexp, val, private) \
81 lll_futex_timed_wait(futexp, val, NULL, private)
83 #define lll_futex_timed_wait(futexp, val, timespec, private) \
85 INTERNAL_SYSCALL_DECL (__err); \
87 __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
88 __lll_private_flag (FUTEX_WAIT, private), \
93 #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
95 INTERNAL_SYSCALL_DECL (__err); \
97 int __op = FUTEX_WAIT_BITSET | clockbit; \
98 __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp), \
99 __lll_private_flag (__op, private), \
100 (val), (timespec), NULL /* Unused. */, \
101 FUTEX_BITSET_MATCH_ANY); \
105 #define lll_futex_wake(futexp, nr, private) \
107 INTERNAL_SYSCALL_DECL (__err); \
109 __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
110 __lll_private_flag (FUTEX_WAKE, private), \
115 #define lll_robust_dead(futexv, private) \
118 int *__futexp = &(futexv); \
119 atomic_or (__futexp, FUTEX_OWNER_DIED); \
120 lll_futex_wake (__futexp, 1, private); \
124 /* Returns non-zero if error happened, zero if success. */
125 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
127 INTERNAL_SYSCALL_DECL (__err); \
129 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
130 __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
131 (nr_wake), (nr_move), (mutex), (val)); \
132 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
135 /* Returns non-zero if error happened, zero if success. */
136 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
138 INTERNAL_SYSCALL_DECL (__err); \
140 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
141 __lll_private_flag (FUTEX_WAKE_OP, private), \
142 (nr_wake), (nr_wake2), (futexp2), \
143 FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
144 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
147 /* Priority Inheritance support. */
148 #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
149 lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
151 #define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \
154 INTERNAL_SYSCALL_DECL (__err); \
156 int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
158 __ret = INTERNAL_SYSCALL (futex, __err, 5, (futexp), \
159 __lll_private_flag (__op, private), \
160 (val), (timespec), mutex); \
164 #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
166 INTERNAL_SYSCALL_DECL (__err); \
168 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
169 __lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
170 (nr_wake), (nr_move), (mutex), (val)); \
171 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
174 #define lll_trylock(lock) \
175 atomic_compare_and_exchange_val_acq (&(lock), 1, 0)
177 #define lll_cond_trylock(lock) \
178 atomic_compare_and_exchange_val_acq (&(lock), 2, 0)
180 #define lll_robust_trylock(lock, id) \
181 atomic_compare_and_exchange_val_acq (&(lock), id, 0)
183 extern void __lll_lock_wait_private (int *futex) attribute_hidden;
184 extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
185 extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
187 #define __lll_lock(futex, private) \
189 int *__futex = (futex); \
190 if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, \
193 if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
194 __lll_lock_wait_private (__futex); \
196 __lll_lock_wait (__futex, private); \
199 #define lll_lock(futex, private) __lll_lock (&(futex), private)
202 #define __lll_robust_lock(futex, id, private) \
204 int *__futex = (futex); \
207 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
209 __val = __lll_robust_lock_wait (__futex, private); \
212 #define lll_robust_lock(futex, id, private) \
213 __lll_robust_lock (&(futex), id, private)
216 #define __lll_cond_lock(futex, private) \
218 int *__futex = (futex); \
219 if (__builtin_expect (atomic_exchange_acq (__futex, 2), 0)) \
220 __lll_lock_wait (__futex, private); \
222 #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
225 #define lll_robust_cond_lock(futex, id, private) \
226 __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
229 extern int __lll_timedlock_wait (int *futex, const struct timespec *,
230 int private) attribute_hidden;
231 extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *,
232 int private) attribute_hidden;
234 #define __lll_timedlock(futex, abstime, private) \
236 int *__futex = (futex); \
239 if (__builtin_expect (atomic_exchange_acq (__futex, 1), 0)) \
240 __val = __lll_timedlock_wait (__futex, abstime, private); \
243 #define lll_timedlock(futex, abstime, private) \
244 __lll_timedlock (&(futex), abstime, private)
247 #define __lll_robust_timedlock(futex, abstime, id, private) \
249 int *__futex = (futex); \
252 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
254 __val = __lll_robust_timedlock_wait (__futex, abstime, private); \
257 #define lll_robust_timedlock(futex, abstime, id, private) \
258 __lll_robust_timedlock (&(futex), abstime, id, private)
261 #define __lll_unlock(futex, private) \
263 ({ int *__futex = (futex); \
264 int __oldval = atomic_exchange_rel (__futex, 0); \
265 if (__builtin_expect (__oldval > 1, 0)) \
266 lll_futex_wake (__futex, 1, private); \
268 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
271 #define __lll_robust_unlock(futex, private) \
273 ({ int *__futex = (futex); \
274 int __oldval = atomic_exchange_rel (__futex, 0); \
275 if (__builtin_expect (__oldval & FUTEX_WAITERS, 0)) \
276 lll_futex_wake (__futex, 1, private); \
278 #define lll_robust_unlock(futex, private) \
279 __lll_robust_unlock(&(futex), private)
282 #define lll_islocked(futex) \
286 /* Our internal lock implementation is identical to the binary-compatible
287 mutex implementation. */
289 /* Initializers for lock. */
290 #define LLL_LOCK_INITIALIZER (0)
291 #define LLL_LOCK_INITIALIZER_LOCKED (1)
293 /* The states of a lock are:
295 1 - taken by one user
296 >1 - taken by more users */
298 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
299 wakeup when the clone terminates. The memory location contains the
300 thread ID while the clone is running and is reset to zero
302 #define lll_wait_tid(tid) \
304 __typeof (tid) __tid; \
305 while ((__tid = (tid)) != 0) \
306 lll_futex_wait (&(tid), __tid, LLL_SHARED); \
309 extern int __lll_timedwait_tid (int *, const struct timespec *)
312 #define lll_timedwait_tid(tid, abstime) \
316 __res = __lll_timedwait_tid (&(tid), (abstime)); \
320 #endif /* lowlevellock.h */