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) 2002, 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _LOWLEVELLOCK_H
#define _LOWLEVELLOCK_H 1
#include <time.h>
#include <sys/param.h>
#include <bits/pthreadtypes.h>
#include <atomic.h>
#include <sysdep.h>
/* We have a separate internal lock implementation which is not tied
to binary compatibility. */
/* Type for lock object. */
typedef int lll_lock_t;
/* Initializers for lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
#include <tls.h>
#ifndef LOCK_INSTR
# define LOCK_INSTR "lock;"
#endif
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
/* Initializer for compatibility lock. */
#define LLL_MUTEX_LOCK_INITIALIZER (0)
#define LLL_MUTEX_LOCK_INITIALIZER_LOCKED (1)
#define LLL_MUTEX_LOCK_INITIALIZER_WAITERS (2)
#ifdef PIC
# define LLL_EBX_LOAD "xchgl %2, %%ebx\n"
# define LLL_EBX_REG "D"
#else
# define LLL_EBX_LOAD
# define LLL_EBX_REG "b"
#endif
#define LLL_ENTER_KERNEL "int $0x80\n\t"
/* Delay in spinlock loop. */
#define BUSY_WAIT_NOP __asm__ ("rep; nop")
#define lll_futex_wait(futex, val) \
lll_futex_timed_wait (futex, val, NULL)
#define lll_futex_timed_wait(futex, val, timeout) \
({ \
int __ret; \
register __typeof (val) _val __asm__ ("edx") = (val); \
__asm__ __volatile (LLL_EBX_LOAD \
LLL_ENTER_KERNEL \
LLL_EBX_LOAD \
: "=a" (__ret) \
: "0" (SYS_futex), LLL_EBX_REG (futex), "S" (timeout), \
"c" (FUTEX_WAIT), "d" (_val), \
"i" (offsetof (tcbhead_t, sysinfo))); \
__ret; })
#define lll_futex_wake(futex, nr) \
({ \
int __ret; \
register __typeof (nr) _nr __asm__ ("edx") = (nr); \
__asm__ __volatile (LLL_EBX_LOAD \
LLL_ENTER_KERNEL \
LLL_EBX_LOAD \
: "=a" (__ret) \
: "0" (SYS_futex), LLL_EBX_REG (futex), \
"c" (FUTEX_WAKE), "d" (_nr), \
"i" (0) /* phony, to align next arg's number */, \
"i" (offsetof (tcbhead_t, sysinfo))); \
__ret; })
/* Does not preserve %eax and %ecx. */
extern int __lll_mutex_lock_wait (int val, int *__futex)
__attribute ((regparm (2))) attribute_hidden;
/* Does not preserve %eax, %ecx, and %edx. */
extern int __lll_mutex_timedlock_wait (int val, int *__futex,
const struct timespec *abstime)
__attribute ((regparm (3))) attribute_hidden;
/* Preserves all registers but %eax. */
extern int __lll_mutex_unlock_wake (int *__futex)
__attribute ((regparm (1))) attribute_hidden;
/* NB: in the lll_mutex_trylock macro we simply return the value in %eax
after the cmpxchg instruction. In case the operation succeded this
value is zero. In case the operation failed, the cmpxchg instruction
has loaded the current value of the memory work which is guaranteed
to be nonzero. */
#define lll_mutex_trylock(futex) \
({ int ret; \
__asm__ __volatile (LOCK_INSTR "cmpxchgl %2, %1" \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_MUTEX_LOCK_INITIALIZER_LOCKED), "m" (futex),\
"0" (LLL_MUTEX_LOCK_INITIALIZER) \
: "memory"); \
ret; })
#define lll_mutex_cond_trylock(futex) \
({ int ret; \
__asm__ __volatile (LOCK_INSTR "cmpxchgl %2, %1" \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_MUTEX_LOCK_INITIALIZER_WAITERS), \
"m" (futex), "0" (LLL_MUTEX_LOCK_INITIALIZER) \
: "memory"); \
ret; })
#define lll_mutex_lock(futex) \
(void) ({ int ignore1, ignore2; \
__asm__ __volatile (LOCK_INSTR "cmpxchgl %1, %2\n\t" \
"jnz _L_mutex_lock_%=\n\t" \
".subsection 1\n\t" \
".type _L_mutex_lock_%=,@function\n" \
"_L_mutex_lock_%=:\n\t" \
"leal %2, %%ecx\n\t" \
"call __lll_mutex_lock_wait\n\t" \
"jmp 1f\n\t" \
".size _L_mutex_lock_%=,.-_L_mutex_lock_%=\n" \
".previous\n" \
"1:" \
: "=a" (ignore1), "=c" (ignore2), "=m" (futex) \
: "0" (0), "1" (1), "m" (futex) \
: "memory"); })
/* Special version of lll_mutex_lock which causes the unlock function to
always wakeup waiters. */
#define lll_mutex_cond_lock(futex) \
(void) ({ int ignore1, ignore2; \
__asm__ __volatile (LOCK_INSTR "cmpxchgl %1, %2\n\t" \
"jnz _L_mutex_cond_lock_%=\n\t" \
".subsection 1\n\t" \
".type _L_mutex_cond_lock_%=,@function\n" \
"_L_mutex_cond_lock_%=:\n\t" \
"leal %2, %%ecx\n\t" \
"call __lll_mutex_lock_wait\n\t" \
"jmp 1f\n\t" \
".size _L_mutex_cond_lock_%=,.-_L_mutex_cond_lock_%=\n" \
".previous\n" \
"1:" \
: "=a" (ignore1), "=c" (ignore2), "=m" (futex) \
: "0" (0), "1" (2), "m" (futex) \
: "memory"); })
#define lll_mutex_timedlock(futex, timeout) \
({ int result, ignore1, ignore2; \
__asm__ __volatile (LOCK_INSTR "cmpxchgl %1, %3\n\t" \
"jnz _L_mutex_timedlock_%=\n\t" \
".subsection 1\n\t" \
".type _L_mutex_timedlock_%=,@function\n" \
"_L_mutex_timedlock_%=:\n\t" \
"leal %3, %%ecx\n\t" \
"movl %7, %%edx\n\t" \
"call __lll_mutex_timedlock_wait\n\t" \
"jmp 1f\n\t" \
".size _L_mutex_timedlock_%=,.-_L_mutex_timedlock_%=\n"\
".previous\n" \
"1:" \
: "=a" (result), "=c" (ignore1), "=&d" (ignore2), \
"=m" (futex) \
: "0" (0), "1" (1), "m" (futex), "m" (timeout) \
: "memory"); \
result; })
#define lll_mutex_unlock(futex) \
(void) ({ int ignore; \
__asm__ __volatile (LOCK_INSTR "subl $1,%0\n\t" \
"jne _L_mutex_unlock_%=\n\t" \
".subsection 1\n\t" \
".type _L_mutex_unlock_%=,@function\n" \
"_L_mutex_unlock_%=:\n\t" \
"leal %0, %%eax\n\t" \
"call __lll_mutex_unlock_wake\n\t" \
"jmp 1f\n\t" \
".size _L_mutex_unlock_%=,.-_L_mutex_unlock_%=\n" \
".previous\n" \
"1:" \
: "=m" (futex), "=&a" (ignore) \
: "m" (futex) \
: "memory"); })
#define lll_mutex_islocked(futex) \
(futex != 0)
extern int __lll_lock_wait (int val, int *__futex)
__attribute ((regparm (2))) attribute_hidden;
extern int __lll_unlock_wake (int *__futex)
__attribute ((regparm (1))) attribute_hidden;
extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
/* The states of a lock are:
0 - untaken
1 - taken by one user
2 - taken by more users */
#if defined NOT_IN_libc
# define lll_trylock(futex) lll_mutex_trylock (futex)
# define lll_lock(futex) lll_mutex_lock (futex)
# define lll_unlock(futex) lll_mutex_unlock (futex)
#else
/* Special versions of the macros for use in libc itself. They avoid
the lock prefix when the thread library is not used. */
# define lll_trylock(futex) \
({ unsigned char ret; \
__asm__ __volatile ("cmpl $0, %%gs:%P5\n\t" \
"je,pt 0f\n\t" \
"lock\n" \
"0:\tcmpxchgl %2, %1; setne %0" \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_MUTEX_LOCK_INITIALIZER_LOCKED), "m" (futex),\
"0" (LLL_MUTEX_LOCK_INITIALIZER), \
"i" (offsetof (tcbhead_t, multiple_threads)) \
: "memory"); \
ret; })
# define lll_lock(futex) \
(void) ({ int ignore1, ignore2; \
__asm__ __volatile ("cmpl $0, %%gs:%P6\n\t" \
"je,pt 0f\n\t" \
"lock\n" \
"0:\tcmpxchgl %1, %2\n\t" \
"jnz _L_mutex_lock_%=\n\t" \
".subsection 1\n\t" \
".type _L_mutex_lock_%=,@function\n" \
"_L_mutex_lock_%=:\n\t" \
"leal %2, %%ecx\n\t" \
"call __lll_mutex_lock_wait\n\t" \
"jmp 1f\n\t" \
".size _L_mutex_lock_%=,.-_L_mutex_lock_%=\n" \
".previous\n" \
"1:" \
: "=a" (ignore1), "=c" (ignore2), "=m" (futex) \
: "0" (0), "1" (1), "m" (futex), \
"i" (offsetof (tcbhead_t, multiple_threads)) \
: "memory"); })
# define lll_unlock(futex) \
(void) ({ int ignore; \
__asm__ __volatile ("cmpl $0, %%gs:%P3\n\t" \
"je,pt 0f\n\t" \
"lock\n" \
"0:\tsubl $1,%0\n\t" \
"jne _L_mutex_unlock_%=\n\t" \
".subsection 1\n\t" \
".type _L_mutex_unlock_%=,@function\n" \
"_L_mutex_unlock_%=:\n\t" \
"leal %0, %%eax\n\t" \
"call __lll_mutex_unlock_wake\n\t" \
"jmp 1f\n\t" \
".size _L_mutex_unlock_%=,.-_L_mutex_unlock_%=\n" \
".previous\n" \
"1:" \
: "=m" (futex), "=&a" (ignore) \
: "m" (futex), \
"i" (offsetof (tcbhead_t, multiple_threads)) \
: "memory"); })
#endif
#define lll_islocked(futex) \
(futex != LLL_LOCK_INITIALIZER)
/* The kernel notifies a process with uses CLONE_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.
The macro parameter must not have any side effect. */
#define lll_wait_tid(tid) \
({ \
int __ret; \
register __typeof (tid) _tid __asm__ ("edx") = (tid); \
if (_tid != 0) \
__asm__ __volatile (LLL_EBX_LOAD \
"1:\tmovl %1, %%eax\n\t" \
LLL_ENTER_KERNEL \
"cmpl $0, (%%ebx)\n\t" \
"jne,pn 1b\n\t" \
LLL_EBX_LOAD \
: "=&a" (__ret) \
: "i" (SYS_futex), LLL_EBX_REG (&tid), "S" (0), \
"c" (FUTEX_WAIT), "d" (_tid), \
"i" (offsetof (tcbhead_t, sysinfo))); \
__ret; })
extern int __lll_timedwait_tid (int *tid, const struct timespec *abstime)
__attribute__ ((regparm (2))) attribute_hidden;
#define lll_timedwait_tid(tid, abstime) \
({ \
int __result = 0; \
if (tid != 0) \
{ \
if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) \
__result = EINVAL; \
else \
__result = __lll_timedwait_tid (&tid, abstime); \
} \
__result; })
/* Conditional variable handling. */
extern void __lll_cond_wait (pthread_cond_t *cond)
__attribute ((regparm (1))) attribute_hidden;
extern int __lll_cond_timedwait (pthread_cond_t *cond,
const struct timespec *abstime)
__attribute ((regparm (2))) attribute_hidden;
extern void __lll_cond_wake (pthread_cond_t *cond)
__attribute ((regparm (1))) attribute_hidden;
extern void __lll_cond_broadcast (pthread_cond_t *cond)
__attribute ((regparm (1))) attribute_hidden;
#define lll_cond_wait(cond) \
__lll_cond_wait (cond)
#define lll_cond_timedwait(cond, abstime) \
__lll_cond_timedwait (cond, abstime)
#define lll_cond_wake(cond) \
__lll_cond_wake (cond)
#define lll_cond_broadcast(cond) \
__lll_cond_broadcast (cond)
#endif /* lowlevellock.h */
|
