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
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
|
/* Copyright (C) 2003-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.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>
#define SYS_futex 238
#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_WAIT_REQUEUE_PI 11
#define FUTEX_CMP_REQUEUE_PI 12
#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(futex, val, private) \
lll_futex_timed_wait (futex, val, NULL, private)
#define lll_futex_timed_wait(futexp, val, timespec, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
\
INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
__lll_private_flag (FUTEX_WAIT, private), \
(val), (timespec)); \
})
#define lll_futex_timed_wait_bitset(futexp, val, timespec, clockbit, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
int __op = FUTEX_WAIT_BITSET | clockbit; \
\
INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
__lll_private_flag (__op, private), \
(val), (timespec), NULL /* Unused. */, \
FUTEX_BITSET_MATCH_ANY); \
})
#define lll_futex_wake(futexp, nr, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
\
INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
__lll_private_flag (FUTEX_WAKE, private), \
(nr), 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); \
})
/* Priority Inheritance support. */
#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \
lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)
#define lll_futex_timed_wait_requeue_pi(futexp, val, timespec, clockbit, \
mutex, private) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
int __op = FUTEX_WAIT_REQUEUE_PI | clockbit; \
\
INTERNAL_SYSCALL (futex, __err, 5, (futexp), \
__lll_private_flag (__op, private), \
(val), (timespec), mutex); \
})
#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, val, priv) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
__lll_private_flag (FUTEX_CMP_REQUEUE_PI, priv),\
(nr_wake), (nr_move), (mutex), (val)); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
})
#define lll_compare_and_swap(futex, oldval, newval, operation) \
do { \
__typeof (futex) __futex = (futex); \
__asm __volatile (" l %1,%0\n" \
"0: " operation "\n" \
" cs %1,%2,%0\n" \
" jl 0b\n" \
"1:" \
: "=Q" (*__futex), "=&d" (oldval), "=&d" (newval) \
: "m" (*__futex) : "cc", "memory" ); \
} while (0)
static inline int
__attribute__ ((always_inline))
__lll_trylock (int *futex)
{
unsigned int old;
__asm __volatile ("cs %0,%3,%1"
: "=d" (old), "=Q" (*futex)
: "0" (0), "d" (1), "m" (*futex) : "cc", "memory" );
return old != 0;
}
#define lll_trylock(futex) __lll_trylock (&(futex))
static inline int
__attribute__ ((always_inline))
__lll_cond_trylock (int *futex)
{
unsigned int old;
__asm __volatile ("cs %0,%3,%1"
: "=d" (old), "=Q" (*futex)
: "0" (0), "d" (2), "m" (*futex) : "cc", "memory" );
return old != 0;
}
#define lll_cond_trylock(futex) __lll_cond_trylock (&(futex))
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;
static inline void
__attribute__ ((always_inline))
__lll_lock (int *futex, int private)
{
if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0)))
{
if (__builtin_constant_p (private) && private == LLL_PRIVATE)
__lll_lock_wait_private (futex);
else
__lll_lock_wait (futex, private);
}
}
#define lll_lock(futex, private) __lll_lock (&(futex), private)
static inline int
__attribute__ ((always_inline))
__lll_robust_lock (int *futex, int id, int private)
{
int result = 0;
if (__builtin_expect (atomic_compare_and_exchange_bool_acq (futex, id, 0),
0))
result = __lll_robust_lock_wait (futex, private);
return result;
}
#define lll_robust_lock(futex, id, private) \
__lll_robust_lock (&(futex), id, private)
static inline void
__attribute__ ((always_inline))
__lll_cond_lock (int *futex, int private)
{
if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 2, 0)))
__lll_lock_wait (futex, private);
}
#define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private)
#define lll_robust_cond_lock(futex, id, private) \
__lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private)
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;
static inline int
__attribute__ ((always_inline))
__lll_timedlock (int *futex, const struct timespec *abstime, int private)
{
int result = 0;
if (__glibc_unlikely (atomic_compare_and_exchange_bool_acq (futex, 1, 0)))
result = __lll_timedlock_wait (futex, abstime, private);
return result;
}
#define lll_timedlock(futex, abstime, private) \
__lll_timedlock (&(futex), abstime, private)
#ifdef ENABLE_LOCK_ELISION
extern int __lll_timedlock_elision
(int *futex, short *adapt_count, const struct timespec *timeout, int private)
attribute_hidden;
# define lll_timedlock_elision(futex, adapt_count, timeout, private) \
__lll_timedlock_elision(&(futex), &(adapt_count), timeout, private)
#endif
static inline int
__attribute__ ((always_inline))
__lll_robust_timedlock (int *futex, const struct timespec *abstime,
int id, int private)
{
int result = 0;
if (__builtin_expect (atomic_compare_and_exchange_bool_acq (futex, id, 0),
0))
result = __lll_robust_timedlock_wait (futex, abstime, private);
return result;
}
#define lll_robust_timedlock(futex, abstime, id, private) \
__lll_robust_timedlock (&(futex), abstime, id, private)
#define __lll_unlock(futex, private) \
(void) \
({ int __oldval; \
int __newval = 0; \
int *__futexp = (futex); \
\
lll_compare_and_swap (__futexp, __oldval, __newval, "slr %2,%2"); \
if (__glibc_unlikely (__oldval > 1)) \
lll_futex_wake (__futexp, 1, private); \
})
#define lll_unlock(futex, private) __lll_unlock(&(futex), private)
#define __lll_robust_unlock(futex, private) \
(void) \
({ int __oldval; \
int __newval = 0; \
int *__futexp = (futex); \
\
lll_compare_and_swap (__futexp, __oldval, __newval, "slr %2,%2"); \
if (__glibc_unlikely (__oldval & FUTEX_WAITERS)) \
lll_futex_wake (__futexp, 1, private); \
})
#define lll_robust_unlock(futex, private) \
__lll_robust_unlock(&(futex), private)
#define lll_islocked(futex) \
(futex != 0)
/* Initializers for lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
/* 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(ptid) \
do \
{ \
int __tid; \
\
while ((__tid = *ptid) != 0) \
lll_futex_wait (ptid, __tid, LLL_SHARED); \
} \
while (0)
#define lll_wait_tid(tid) __lll_wait_tid(&(tid))
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; \
})
#ifdef ENABLE_LOCK_ELISION
extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
attribute_hidden;
extern int __lll_unlock_elision(int *futex, int private)
attribute_hidden;
extern int __lll_trylock_elision(int *futex, short *adapt_count)
attribute_hidden;
# define lll_lock_elision(futex, adapt_count, private) \
__lll_lock_elision (&(futex), &(adapt_count), private)
# define lll_unlock_elision(futex, private) \
__lll_unlock_elision (&(futex), private)
# define lll_trylock_elision(futex, adapt_count) \
__lll_trylock_elision(&(futex), &(adapt_count))
#endif
#endif /* lowlevellock.h */
|
