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glibc/sysdeps/unix/sysv/linux/lowlevellock-futex.h
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/* Low-level locking access to futex facilities. Linux version. | |
Copyright (C) 2005-2016 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) \ | |
({ \ | |
/* Prevent warnings in callers of this macro. */ \ | |
int __lll_private_flag_priv __attribute__ ((unused)); \ | |
__lll_private_flag_priv = (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 */ |