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3df6f22e | 1 | /* Low-level locking access to futex facilities. Linux version. |
688903eb | 2 | Copyright (C) 2005-2018 Free Software Foundation, Inc. |
3df6f22e RM |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library. If not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #ifndef _LOWLEVELLOCK_FUTEX_H | |
20 | #define _LOWLEVELLOCK_FUTEX_H 1 | |
21 | ||
76f71081 | 22 | #ifndef __ASSEMBLER__ |
3df6f22e RM |
23 | #include <sysdep.h> |
24 | #include <tls.h> | |
25 | #include <kernel-features.h> | |
76f71081 | 26 | #endif |
3df6f22e RM |
27 | |
28 | #define FUTEX_WAIT 0 | |
29 | #define FUTEX_WAKE 1 | |
30 | #define FUTEX_REQUEUE 3 | |
31 | #define FUTEX_CMP_REQUEUE 4 | |
32 | #define FUTEX_WAKE_OP 5 | |
33 | #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1) | |
34 | #define FUTEX_LOCK_PI 6 | |
35 | #define FUTEX_UNLOCK_PI 7 | |
36 | #define FUTEX_TRYLOCK_PI 8 | |
37 | #define FUTEX_WAIT_BITSET 9 | |
38 | #define FUTEX_WAKE_BITSET 10 | |
39 | #define FUTEX_WAIT_REQUEUE_PI 11 | |
40 | #define FUTEX_CMP_REQUEUE_PI 12 | |
41 | #define FUTEX_PRIVATE_FLAG 128 | |
42 | #define FUTEX_CLOCK_REALTIME 256 | |
43 | ||
44 | #define FUTEX_BITSET_MATCH_ANY 0xffffffff | |
45 | ||
46 | /* Values for 'private' parameter of locking macros. Yes, the | |
47 | definition seems to be backwards. But it is not. The bit will be | |
48 | reversed before passing to the system call. */ | |
49 | #define LLL_PRIVATE 0 | |
50 | #define LLL_SHARED FUTEX_PRIVATE_FLAG | |
51 | ||
76f71081 | 52 | #ifndef __ASSEMBLER__ |
3df6f22e | 53 | |
4f41c682 | 54 | #if IS_IN (libc) || IS_IN (rtld) |
3df6f22e RM |
55 | /* In libc.so or ld.so all futexes are private. */ |
56 | # ifdef __ASSUME_PRIVATE_FUTEX | |
389fdf78 TR |
57 | # define __lll_private_flag(fl, private) \ |
58 | ({ \ | |
59 | /* Prevent warnings in callers of this macro. */ \ | |
60 | int __lll_private_flag_priv __attribute__ ((unused)); \ | |
61 | __lll_private_flag_priv = (private); \ | |
62 | ((fl) | FUTEX_PRIVATE_FLAG); \ | |
63 | }) | |
3df6f22e RM |
64 | # else |
65 | # define __lll_private_flag(fl, private) \ | |
66 | ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) | |
67 | # endif | |
68 | #else | |
69 | # ifdef __ASSUME_PRIVATE_FUTEX | |
70 | # define __lll_private_flag(fl, private) \ | |
71 | (((fl) | FUTEX_PRIVATE_FLAG) ^ (private)) | |
72 | # else | |
73 | # define __lll_private_flag(fl, private) \ | |
74 | (__builtin_constant_p (private) \ | |
75 | ? ((private) == 0 \ | |
76 | ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \ | |
77 | : (fl)) \ | |
78 | : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \ | |
79 | & THREAD_GETMEM (THREAD_SELF, header.private_futex)))) | |
80 | # endif | |
81 | #endif | |
82 | ||
83 | #define lll_futex_syscall(nargs, futexp, op, ...) \ | |
84 | ({ \ | |
85 | INTERNAL_SYSCALL_DECL (__err); \ | |
86 | long int __ret = INTERNAL_SYSCALL (futex, __err, nargs, futexp, op, \ | |
87 | __VA_ARGS__); \ | |
88 | (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err)) \ | |
89 | ? -INTERNAL_SYSCALL_ERRNO (__ret, __err) : 0); \ | |
90 | }) | |
91 | ||
92 | #define lll_futex_wait(futexp, val, private) \ | |
93 | lll_futex_timed_wait (futexp, val, NULL, private) | |
94 | ||
95 | #define lll_futex_timed_wait(futexp, val, timeout, private) \ | |
96 | lll_futex_syscall (4, futexp, \ | |
97 | __lll_private_flag (FUTEX_WAIT, private), \ | |
98 | val, timeout) | |
99 | ||
100 | #define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \ | |
101 | lll_futex_syscall (6, futexp, \ | |
102 | __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \ | |
103 | private), \ | |
104 | val, timeout, NULL /* Unused. */, \ | |
105 | FUTEX_BITSET_MATCH_ANY) | |
106 | ||
107 | #define lll_futex_wake(futexp, nr, private) \ | |
108 | lll_futex_syscall (4, futexp, \ | |
109 | __lll_private_flag (FUTEX_WAKE, private), nr, 0) | |
110 | ||
111 | /* Returns non-zero if error happened, zero if success. */ | |
112 | #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \ | |
113 | lll_futex_syscall (6, futexp, \ | |
114 | __lll_private_flag (FUTEX_CMP_REQUEUE, private), \ | |
115 | nr_wake, nr_move, mutex, val) | |
116 | ||
117 | /* Returns non-zero if error happened, zero if success. */ | |
118 | #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \ | |
119 | lll_futex_syscall (6, futexp, \ | |
120 | __lll_private_flag (FUTEX_WAKE_OP, private), \ | |
121 | nr_wake, nr_wake2, futexp2, \ | |
122 | FUTEX_OP_CLEAR_WAKE_IF_GT_ONE) | |
123 | ||
124 | /* Priority Inheritance support. */ | |
125 | #define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \ | |
126 | lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private) | |
127 | ||
128 | #define lll_futex_timed_wait_requeue_pi(futexp, val, timeout, clockbit, \ | |
129 | mutex, private) \ | |
130 | lll_futex_syscall (5, futexp, \ | |
131 | __lll_private_flag (FUTEX_WAIT_REQUEUE_PI \ | |
132 | | (clockbit), private), \ | |
133 | val, timeout, mutex) | |
134 | ||
135 | ||
136 | #define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex, \ | |
137 | val, private) \ | |
138 | lll_futex_syscall (6, futexp, \ | |
139 | __lll_private_flag (FUTEX_CMP_REQUEUE_PI, \ | |
140 | private), \ | |
141 | nr_wake, nr_move, mutex, val) | |
142 | ||
76f71081 | 143 | #endif /* !__ASSEMBLER__ */ |
3df6f22e RM |
144 | |
145 | #endif /* lowlevellock-futex.h */ |