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
|
/* Copyright (C) 2002-2017 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, see
<http://www.gnu.org/licenses/>. */
#ifndef _LOWLEVELLOCK_H
#define _LOWLEVELLOCK_H 1
#include <stap-probe.h>
#ifndef __ASSEMBLER__
# include <time.h>
# include <sys/param.h>
# include <bits/pthreadtypes.h>
# include <kernel-features.h>
# include <tcb-offsets.h>
# ifndef LOCK_INSTR
# ifdef UP
# define LOCK_INSTR /* nothing */
# else
# define LOCK_INSTR "lock;"
# endif
# endif
#else
# ifndef LOCK
# ifdef UP
# define LOCK
# else
# define LOCK lock
# endif
# endif
#endif
#include <lowlevellock-futex.h>
/* XXX Remove when no assembler code uses futexes anymore. */
#define SYS_futex __NR_futex
#ifndef __ASSEMBLER__
/* Initializer for compatibility lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
#define LLL_LOCK_INITIALIZER_WAITERS (2)
/* NB: in the lll_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. */
#if !IS_IN (libc) || defined UP
# define __lll_trylock_asm LOCK_INSTR "cmpxchgl %2, %1"
#else
# define __lll_trylock_asm "cmpl $0, %%gs:%P5\n\t" \
"je 0f\n\t" \
"lock\n" \
"0:\tcmpxchgl %2, %1"
#endif
#define lll_trylock(futex) \
({ int ret; \
__asm __volatile (__lll_trylock_asm \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_LOCK_INITIALIZER_LOCKED), "m" (futex), \
"0" (LLL_LOCK_INITIALIZER), \
"i" (MULTIPLE_THREADS_OFFSET) \
: "memory"); \
ret; })
#define lll_cond_trylock(futex) \
({ int ret; \
__asm __volatile (LOCK_INSTR "cmpxchgl %2, %1" \
: "=a" (ret), "=m" (futex) \
: "r" (LLL_LOCK_INITIALIZER_WAITERS), \
"m" (futex), "0" (LLL_LOCK_INITIALIZER) \
: "memory"); \
ret; })
#if !IS_IN (libc) || defined UP
# define __lll_lock_asm_start LOCK_INSTR "cmpxchgl %1, %2\n\t"
#else
# define __lll_lock_asm_start "cmpl $0, %%gs:%P6\n\t" \
"je 0f\n\t" \
"lock\n" \
"0:\tcmpxchgl %1, %2\n\t"
#endif
#define lll_lock(futex, private) \
(void) \
({ int ignore1, ignore2; \
if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
__asm __volatile (__lll_lock_asm_start \
"jz 18f\n\t" \
"1:\tleal %2, %%ecx\n" \
"2:\tcall __lll_lock_wait_private\n" \
"18:" \
: "=a" (ignore1), "=c" (ignore2), "=m" (futex) \
: "0" (0), "1" (1), "m" (futex), \
"i" (MULTIPLE_THREADS_OFFSET) \
: "memory"); \
else \
{ \
int ignore3; \
__asm __volatile (__lll_lock_asm_start \
"jz 18f\n\t" \
"1:\tleal %2, %%edx\n" \
"0:\tmovl %8, %%ecx\n" \
"2:\tcall __lll_lock_wait\n" \
"18:" \
: "=a" (ignore1), "=c" (ignore2), \
"=m" (futex), "=&d" (ignore3) \
: "1" (1), "m" (futex), \
"i" (MULTIPLE_THREADS_OFFSET), "0" (0), \
"g" ((int) (private)) \
: "memory"); \
} \
})
/* Special version of lll_lock which causes the unlock function to
always wakeup waiters. */
#define lll_cond_lock(futex, private) \
(void) \
({ int ignore1, ignore2, ignore3; \
__asm __volatile (LOCK_INSTR "cmpxchgl %1, %2\n\t" \
"jz 18f\n\t" \
"1:\tleal %2, %%edx\n" \
"0:\tmovl %7, %%ecx\n" \
"2:\tcall __lll_lock_wait\n" \
"18:" \
: "=a" (ignore1), "=c" (ignore2), "=m" (futex), \
"=&d" (ignore3) \
: "0" (0), "1" (2), "m" (futex), "g" ((int) (private))\
: "memory"); \
})
#define lll_timedlock(futex, timeout, private) \
({ int result, ignore1, ignore2, ignore3; \
__asm __volatile (LOCK_INSTR "cmpxchgl %1, %3\n\t" \
"jz 18f\n\t" \
"1:\tleal %3, %%ecx\n" \
"0:\tmovl %8, %%edx\n" \
"2:\tcall __lll_timedlock_wait\n" \
"18:" \
: "=a" (result), "=c" (ignore1), "=&d" (ignore2), \
"=m" (futex), "=S" (ignore3) \
: "0" (0), "1" (1), "m" (futex), "m" (timeout), \
"4" ((int) (private)) \
: "memory"); \
result; })
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)
#if !IS_IN (libc) || defined UP
# define __lll_unlock_asm LOCK_INSTR "subl $1, %0\n\t"
#else
# define __lll_unlock_asm "cmpl $0, %%gs:%P3\n\t" \
"je 0f\n\t" \
"lock\n" \
"0:\tsubl $1,%0\n\t"
#endif
#define lll_unlock(futex, private) \
(void) \
({ int ignore; \
if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \
__asm __volatile (__lll_unlock_asm \
"je 18f\n\t" \
"1:\tleal %0, %%eax\n" \
"2:\tcall __lll_unlock_wake_private\n" \
"18:" \
: "=m" (futex), "=&a" (ignore) \
: "m" (futex), "i" (MULTIPLE_THREADS_OFFSET) \
: "memory"); \
else \
{ \
int ignore2; \
__asm __volatile (__lll_unlock_asm \
"je 18f\n\t" \
"1:\tleal %0, %%eax\n" \
"0:\tmovl %5, %%ecx\n" \
"2:\tcall __lll_unlock_wake\n" \
"18:" \
: "=m" (futex), "=&a" (ignore), "=&c" (ignore2) \
: "i" (MULTIPLE_THREADS_OFFSET), "m" (futex), \
"g" ((int) (private)) \
: "memory"); \
} \
})
#define lll_islocked(futex) \
(futex != LLL_LOCK_INITIALIZER)
/* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex
wake-up when the clone terminates. The memory location contains the
thread ID while the clone is running and is reset to zero by the kernel
afterwards. The kernel up to version 3.16.3 does not use the private futex
operations for futex wake-up when the clone terminates. */
#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 *tid, const struct timespec *abstime)
__attribute__ ((regparm (2))) attribute_hidden;
/* As lll_wait_tid, but with a timeout. If the timeout occurs then return
ETIMEDOUT. If ABSTIME is invalid, return EINVAL.
XXX Note that this differs from the generic version in that we do the
error checking here and not in __lll_timedwait_tid. */
#define lll_timedwait_tid(tid, abstime) \
({ \
int __result = 0; \
if ((tid) != 0) \
__result = __lll_timedwait_tid (&(tid), (abstime)); \
__result; })
extern int __lll_lock_elision (int *futex, short *adapt_count, int private)
attribute_hidden;
extern int __lll_unlock_elision(int *lock, int private)
attribute_hidden;
extern int __lll_trylock_elision(int *lock, 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, adapt_count, private) \
__lll_unlock_elision (&(futex), private)
#define lll_trylock_elision(futex, adapt_count) \
__lll_trylock_elision(&(futex), &(adapt_count))
#endif /* !__ASSEMBLER__ */
#endif /* lowlevellock.h */
|
