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[glibc.git] / ports / sysdeps / unix / sysv / linux / aarch64 / nptl / lowlevellock.h
blob52f8a7a27dcd3159a3614f575b0793a6f0820b9a
1 /* Copyright (C) 2005-2013 Free Software Foundation, Inc.
2
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, (futexp), \
85 __lll_private_flag (FUTEX_WAIT, private), \
86 (val), (timespec)); \
87 __ret; \
88 })
89
90 #define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
91 ({ \
92 INTERNAL_SYSCALL_DECL (__err); \
93 long int __ret; \
94 int __op = FUTEX_WAIT_BITSET | clockbit; \
95 __ret = INTERNAL_SYSCALL (futex, __err, 6, (long) (futexp), \
96 __lll_private_flag (__op, private), \
97 (val), (timespec), NULL /* Unused. */, \
98 FUTEX_BITSET_MATCH_ANY); \
99 __ret; \
100 })
101
102 #define lll_futex_wake(futexp, nr, private) \
103 ({ \
104 INTERNAL_SYSCALL_DECL (__err); \
105 long int __ret; \
106 __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
107 __lll_private_flag (FUTEX_WAKE, private), \
108 (nr), 0); \
109 __ret; \
110 })
111
112 #define lll_robust_dead(futexv, private) \
113 do \
114 { \
115 int *__futexp = &(futexv); \
116 atomic_or (__futexp, FUTEX_OWNER_DIED); \
117 lll_futex_wake (__futexp, 1, private); \
118 } \
119 while (0)
120
121 /* Returns non-zero if error happened, zero if success. */
122 #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
123 ({ \
124 INTERNAL_SYSCALL_DECL (__err); \
125 long int __ret; \
126 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
127 __lll_private_flag (FUTEX_CMP_REQUEUE, private),\
128 (nr_wake), (nr_move), (mutex), (val)); \
129 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
130 })
131
132
133 /* Returns non-zero if error happened, zero if success. */
134 #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
135 ({ \
136 INTERNAL_SYSCALL_DECL (__err); \
137 long int __ret; \
138 __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
139 __lll_private_flag (FUTEX_WAKE_OP, private), \
140 (nr_wake), (nr_wake2), (futexp2), \
141 FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
142 INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
143 })
144
145
146 #define lll_trylock(lock) \
147 atomic_compare_and_exchange_val_acq(&(lock), 1, 0)
148
149 #define lll_cond_trylock(lock) \
150 atomic_compare_and_exchange_val_acq(&(lock), 2, 0)
151
152 #define __lll_robust_trylock(futex, id) \
153 (atomic_compare_and_exchange_val_acq (futex, id, 0) != 0)
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_val_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 #define __lll_cond_lock(futex, private) \
191 ((void) ({ \
192 int *__futex = (futex); \
193 if (__builtin_expect (atomic_exchange_acq (__futex, 2), 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 #define __lll_timedlock(futex, abstime, private) \
209 ({ \
210 int *__futex = (futex); \
211 int __val = 0; \
212 \
213 if (__builtin_expect (atomic_exchange_acq (__futex, 1), 0)) \
214 __val = __lll_timedlock_wait (__futex, abstime, private); \
215 __val; \
216 })
217 #define lll_timedlock(futex, abstime, private) \
218 __lll_timedlock (&(futex), abstime, private)
219
220
221 #define __lll_robust_timedlock(futex, abstime, id, private) \
222 ({ \
223 int *__futex = (futex); \
224 int __val = 0; \
225 \
226 if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
227 0), 0)) \
228 __val = __lll_robust_timedlock_wait (__futex, abstime, private); \
229 __val; \
230 })
231 #define lll_robust_timedlock(futex, abstime, id, private) \
232 __lll_robust_timedlock (&(futex), abstime, id, private)
233
234
235 #define __lll_unlock(futex, private) \
236 (void) \
237 ({ int *__futex = (futex); \
238 int __oldval = atomic_exchange_rel (__futex, 0); \
239 if (__builtin_expect (__oldval > 1, 0)) \
240 lll_futex_wake (__futex, 1, private); \
241 })
242
243 #define lll_unlock(futex, private) __lll_unlock(&(futex), private)
244
245
246 #define __lll_robust_unlock(futex, private) \
247 (void) \
248 ({ int *__futex = (futex); \
249 int __oldval = atomic_exchange_rel (__futex, 0); \
250 if (__builtin_expect (__oldval & FUTEX_WAITERS, 0)) \
251 lll_futex_wake (__futex, 1, private); \
252 })
253 #define lll_robust_unlock(futex, private) \
254 __lll_robust_unlock(&(futex), private)
255
256
257 #define lll_islocked(futex) \
258 (futex != 0)
259
260
261 /* Our internal lock implementation is identical to the binary-compatible
262 mutex implementation. */
263
264 /* Initializers for lock. */
265 #define LLL_LOCK_INITIALIZER (0)
266 #define LLL_LOCK_INITIALIZER_LOCKED (1)
267
268 /* The states of a lock are:
269 0 - untaken
270 1 - taken by one user
271 >1 - taken by more users */
272
273 /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
274 wakeup when the clone terminates. The memory location contains the
275 thread ID while the clone is running and is reset to zero
276 afterwards. */
277 #define lll_wait_tid(tid) \
278 do { \
279 __typeof (tid) __tid; \
280 while ((__tid = (tid)) != 0) \
281 lll_futex_wait (&(tid), __tid, LLL_SHARED);\
282 } while (0)
283
284 extern int __lll_timedwait_tid (int *, const struct timespec *)
285 attribute_hidden;
286
287 #define lll_timedwait_tid(tid, abstime) \
288 ({ \
289 int __res = 0; \
290 if ((tid) != 0) \
291 __res = __lll_timedwait_tid (&(tid), (abstime)); \
292 __res; \
293 })
294
295 #endif /* lowlevellock.h */
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