summaryrefslogtreecommitdiff
path: root/sysdeps/unix/sysv/linux/lowlevellock-futex.h
blob: 59f6627bdb916bd7e92c6b0f488feb71516472a8 (plain)
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
/* Low-level locking access to futex facilities.  Linux version.
   Copyright (C) 2005-2015 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   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_FUTEX_H
#define _LOWLEVELLOCK_FUTEX_H	1

#ifndef __ASSEMBLER__
#include <sysdep.h>
#include <tls.h>
#include <kernel-features.h>
#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_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

#ifndef __ASSEMBLER__

#if IS_IN (libc) || 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_syscall(nargs, futexp, op, ...)                       \
  ({                                                                    \
    INTERNAL_SYSCALL_DECL (__err);                                      \
    long int __ret = INTERNAL_SYSCALL (futex, __err, nargs, futexp, op, \
				       __VA_ARGS__);                    \
    (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err))         \
     ? -INTERNAL_SYSCALL_ERRNO (__ret, __err) : 0);                     \
  })

#define lll_futex_wait(futexp, val, private) \
  lll_futex_timed_wait (futexp, val, NULL, private)

#define lll_futex_timed_wait(futexp, val, timeout, private)     \
  lll_futex_syscall (4, futexp,                                 \
		     __lll_private_flag (FUTEX_WAIT, private),  \
		     val, timeout)

#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \
  lll_futex_syscall (6, futexp,                                         \
		     __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \
					 private),                      \
		     val, timeout, NULL /* Unused.  */,                 \
		     FUTEX_BITSET_MATCH_ANY)

#define lll_futex_wake(futexp, nr, private)                             \
  lll_futex_syscall (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) \
  lll_futex_syscall (6, futexp,                                         \
		     __lll_private_flag (FUTEX_CMP_REQUEUE, private),   \
		     nr_wake, nr_move, mutex, val)

/* Returns non-zero if error happened, zero if success.  */
#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \
  lll_futex_syscall (6, futexp,                                         \
		     __lll_private_flag (FUTEX_WAKE_OP, private),       \
		     nr_wake, nr_wake2, futexp2,                        \
		     FUTEX_OP_CLEAR_WAKE_IF_GT_ONE)

/* 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, timeout, clockbit, \
					mutex, private)                 \
  lll_futex_syscall (5, futexp,                                         \
		     __lll_private_flag (FUTEX_WAIT_REQUEUE_PI          \
					 | (clockbit), private),        \
		     val, timeout, mutex)


#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex,       \
				 val, private)                          \
  lll_futex_syscall (6, futexp,                                         \
		     __lll_private_flag (FUTEX_CMP_REQUEUE_PI,          \
					 private),                      \
		     nr_wake, nr_move, mutex, val)

#endif  /* !__ASSEMBLER__  */

#endif  /* lowlevellock-futex.h */