1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
|
/* Copyright (C) 2003, 2004, 2006-2008, 2009 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _LOWLEVELLOCK_H
#define _LOWLEVELLOCK_H 1
#include <time.h>
#include <sys/param.h>
#include <bits/pthreadtypes.h>
#include <atomic.h>
#include <kernel-features.h>
#ifndef __NR_futex
# define __NR_futex 221
#endif
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
#define FUTEX_REQUEUE 3
#define FUTEX_CMP_REQUEUE 4
#define FUTEX_WAKE_OP 5
#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
#define FUTEX_LOCK_PI 6
#define FUTEX_UNLOCK_PI 7
#define FUTEX_TRYLOCK_PI 8
#define FUTEX_WAIT_BITSET 9
#define FUTEX_WAKE_BITSET 10
#define FUTEX_PRIVATE_FLAG 128
#define FUTEX_CLOCK_REALTIME 256
#define FUTEX_BITSET_MATCH_ANY 0xffffffff
/* Values for 'private' parameter of locking macros. Yes, the
definition seems to be backwards. But it is not. The bit will be
reversed before passing to the system call. */
#define LLL_PRIVATE 0
#define LLL_SHARED FUTEX_PRIVATE_FLAG
#if !defined NOT_IN_libc || defined IS_IN_rtld
/* In libc.so or ld.so all futexes are private. */
# ifdef __ASSUME_PRIVATE_FUTEX
# define __lll_private_flag(fl, private) \
((fl) | FUTEX_PRIVATE_FLAG)
# else
# define __lll_private_flag(fl, private) \
((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex))
# endif
#else
# ifdef __ASSUME_PRIVATE_FUTEX
# define __lll_private_flag(fl, private) \
(((fl) | FUTEX_PRIVATE_FLAG) ^ (private))
# else
# define __lll_private_flag(fl, private) \
(__builtin_constant_p (private) \
? ((private) == 0 \
? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \
: (fl)) \
: ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \
& THREAD_GETMEM (THREAD_SELF, header.private_futex))))
# endif
#endif
#define lll_futex_wait(futexp, val, private) \
lll_futex_timed_wait (futexp, val, NULL, private)
#define lll_futex_timed_wait(futexp, val, timespec, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
__lll_private_flag (FUTEX_WAIT, private), \
(val), (timespec)); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
})
#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
int __op = FUTEX_WAIT_BITSET | clockbit; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
__lll_private_flag (__op, private), \
(val), (timespec), NULL /* Unused. */, \
FUTEX_BITSET_MATCH_ANY); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
})
#define lll_futex_wake(futexp, nr, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
__lll_private_flag (FUTEX_WAKE, private), \
(nr), 0); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err) ? -__ret : __ret; \
})
#define lll_robust_dead(futexv, private) \
do \
{ \
INTERNAL_SYSCALL_DECL (__err); \
int *__futexp = &(futexv); \
\
atomic_or (__futexp, FUTEX_OWNER_DIED); \
INTERNAL_SYSCALL (futex, __err, 4, __futexp, \
__lll_private_flag (FUTEX_WAKE, private), 1, 0); \
} \
while (0)
/* Returns non-zero if error happened, zero if success. */
#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
__lll_private_flag (FUTEX_CMP_REQUEUE, private),\
(nr_wake), (nr_move), (mutex), (val)); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
})
/* Returns non-zero if error happened, zero if success. */
#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
__lll_private_flag (FUTEX_WAKE_OP, private), \
(nr_wake), (nr_wake2), (futexp2), \
FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
})
#ifdef UP
# define __lll_acq_instr ""
# define __lll_rel_instr ""
#else
# define __lll_acq_instr "isync"
# ifdef _ARCH_PWR4
/*
* Newer powerpc64 processors support the new "light weight" sync (lwsync)
* So if the build is using -mcpu=[power4,power5,power5+,970] we can
* safely use lwsync.
*/
# define __lll_rel_instr "lwsync"
# else
/*
* Older powerpc32 processors don't support the new "light weight"
* sync (lwsync). So the only safe option is to use normal sync
* for all powerpc32 applications.
*/
# define __lll_rel_instr "sync"
# endif
#endif
/* Set *futex to ID if it is 0, atomically. Returns the old value */
#define __lll_robust_trylock(futex, id) \
({ int __val; \
__asm __volatile ("1: lwarx %0,0,%2" MUTEX_HINT_ACQ "\n" \
" cmpwi 0,%0,0\n" \
" bne 2f\n" \
" stwcx. %3,0,%2\n" \
" bne- 1b\n" \
"2: " __lll_acq_instr \
: "=&r" (__val), "=m" (*futex) \
: "r" (futex), "r" (id), "m" (*futex) \
: "cr0", "memory"); \
__val; \
})
#define lll_robust_trylock(lock, id) __lll_robust_trylock (&(lock), id)
/* Set *futex to 1 if it is 0, atomically. Returns the old value */
#define __lll_trylock(futex) __lll_robust_trylock (futex, 1)
#define lll_trylock(lock) __lll_trylock (&(lock))
/* Set *futex to 2 if it is 0, atomically. Returns the old value */
#define __lll_cond_trylock(futex) __lll_robust_trylock (futex, 2)
#define lll_cond_trylock(lock) __lll_cond_trylock (&(lock))
extern void __lll_lock_wait_private (int *futex) attribute_hidden;
extern void __lll_lock_wait (int *futex, int private) attribute_hidden;
extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden;
#define lll_lock(lock, private) \
(void) ({ \
int *__futex = &(lock); \
if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 1, 0),\
0) != 0) \
{ \
if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
__lll_lock_wait_private (__futex); \
else \
__lll_lock_wait (__futex, private); \
} \
})
#define lll_robust_lock(lock, id, private) \
({ \
int *__futex = &(lock); \
int __val = 0; \
if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
0), 0)) \
__val = __lll_robust_lock_wait (__futex, private); \
__val; \
})
#define lll_cond_lock(lock, private) \
(void) ({ \
int *__futex = &(lock); \
if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 2, 0),\
0) != 0) \
__lll_lock_wait (__futex, private); \
})
#define lll_robust_cond_lock(lock, id, private) \
({ \
int *__futex = &(lock); \
int __val = 0; \
int __id = id | FUTEX_WAITERS; \
if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, __id,\
0), 0)) \
__val = __lll_robust_lock_wait (__futex, private); \
__val; \
})
extern int __lll_timedlock_wait
(int *futex, const struct timespec *, int private) attribute_hidden;
extern int __lll_robust_timedlock_wait
(int *futex, const struct timespec *, int private) attribute_hidden;
#define lll_timedlock(lock, abstime, private) \
({ \
int *__futex = &(lock); \
int __val = 0; \
if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 1, 0),\
0) != 0) \
__val = __lll_timedlock_wait (__futex, abstime, private); \
__val; \
})
#define lll_robust_timedlock(lock, abstime, id, private) \
({ \
int *__futex = &(lock); \
int __val = 0; \
if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \
0), 0)) \
__val = __lll_robust_timedlock_wait (__futex, abstime, private); \
__val; \
})
#define lll_unlock(lock, private) \
((void) ({ \
int *__futex = &(lock); \
int __val = atomic_exchange_rel (__futex, 0); \
if (__builtin_expect (__val > 1, 0)) \
lll_futex_wake (__futex, 1, private); \
}))
#define lll_robust_unlock(lock, private) \
((void) ({ \
int *__futex = &(lock); \
int __val = atomic_exchange_rel (__futex, 0); \
if (__builtin_expect (__val & FUTEX_WAITERS, 0)) \
lll_futex_wake (__futex, 1, private); \
}))
#define lll_islocked(futex) \
(futex != 0)
/* Initializers for lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
/* The states of a lock are:
0 - untaken
1 - taken by one user
>1 - taken by more users */
/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
wakeup when the clone terminates. The memory location contains the
thread ID while the clone is running and is reset to zero
afterwards. */
#define lll_wait_tid(tid) \
do { \
__typeof (tid) __tid; \
while ((__tid = (tid)) != 0) \
lll_futex_wait (&(tid), __tid, LLL_SHARED); \
} while (0)
extern int __lll_timedwait_tid (int *, const struct timespec *)
attribute_hidden;
#define lll_timedwait_tid(tid, abstime) \
({ \
int __res = 0; \
if ((tid) != 0) \
__res = __lll_timedwait_tid (&(tid), (abstime)); \
__res; \
})
#endif /* lowlevellock.h */
|
GitWeb