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/* Low-level locking access to futex facilities. Linux/i386 version.
Copyright (C) 2014 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
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
#define FUTEX_CMP_REQUEUE 4
#define FUTEX_WAKE_OP 5
#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
#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1)
/* 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
#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)) \
: ({ unsigned int __fl = ((private) ^ FUTEX_PRIVATE_FLAG); \
asm ("andl %%gs:%P1, %0" : "+r" (__fl) \
: "i" (offsetof (struct pthread, header.private_futex))); \
__fl | (fl); }))
# endif
#endif
#ifndef __ASSEMBLER__
/* To avoid naming conflicts with lowlevellock.h, use a different prefix
here. */
#ifdef PIC
# define LLLF_EBX_LOAD "xchgl %2, %%ebx\n"
# define LLLF_EBX_REG "D"
#else
# define LLLF_EBX_LOAD
# define LLLF_EBX_REG "b"
#endif
#ifdef I386_USE_SYSENTER
# ifdef SHARED
# define LLLF_ENTER_KERNEL "call *%%gs:%P6\n\t"
# else
# define LLLF_ENTER_KERNEL "call *_dl_sysinfo\n\t"
# endif
#else
# define LLLF_ENTER_KERNEL "int $0x80\n\t"
#endif
#define lll_futex_wait(futex, val, private) \
lll_futex_timed_wait (futex, val, NULL, private)
#define lll_futex_timed_wait(futex, val, timeout, private) \
({ \
int __status; \
register __typeof (val) _val asm ("edx") = (val); \
__asm __volatile (LLLF_EBX_LOAD \
LLLF_ENTER_KERNEL \
LLLF_EBX_LOAD \
: "=a" (__status) \
: "0" (SYS_futex), LLLF_EBX_REG (futex), "S" (timeout), \
"c" (__lll_private_flag (FUTEX_WAIT, private)), \
"d" (_val), "i" (offsetof (tcbhead_t, sysinfo)) \
: "memory"); \
__status; \
})
#define lll_futex_wake(futex, nr, private) \
({ \
int __status; \
register __typeof (nr) _nr asm ("edx") = (nr); \
LIBC_PROBE (lll_futex_wake, 3, futex, nr, private); \
__asm __volatile (LLLF_EBX_LOAD \
LLLF_ENTER_KERNEL \
LLLF_EBX_LOAD \
: "=a" (__status) \
: "0" (SYS_futex), LLLF_EBX_REG (futex), \
"c" (__lll_private_flag (FUTEX_WAKE, private)), \
"d" (_nr), \
"i" (0) /* phony, to align next arg's number */, \
"i" (offsetof (tcbhead_t, sysinfo))); \
__status; \
})
#endif /* !__ASSEMBLER__ */
#endif /* lowlevellock-futex.h */
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