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/* Copyright (C) 2003, 2004, 2006, 2007, 2008 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Jakub Jelinek <jakub@redhat.com>, 2003.
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 Libr \ary; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#ifndef _LOWLEVELLOCK_H
#define _LOWLEVELLOCK_H 1
#include <time.h>
#include <sys/param.h>
#include <bits/pthreadtypes.h>
#include <atomic.h>
#include <sysdep.h>
#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)
/* Initializer for compatibility lock. */
#define LLL_MUTEX_LOCK_INITIALIZER (0)
#define lll_futex_wait(futexp, val) \
lll_futex_timed_wait (futexp, val, NULL)
#define lll_futex_timed_wait(futexp, val, timespec) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
__ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
FUTEX_WAIT, (val), (timespec)); \
__ret; \
})
#define lll_futex_wake(futexp, nr) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
__ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \
FUTEX_WAKE, (nr), 0); \
__ret; \
})
/* Returns non-zero if error happened, zero if success. */
#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
FUTEX_CMP_REQUEUE, (nr_wake), (nr_move), (mutex), (val)); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
})
#define lll_robust_dead(futexv) \
do \
{ \
int *__futexp = &(futexv); \
atomic_or (__futexp, FUTEX_OWNER_DIED); \
lll_futex_wake (__futexp, 1); \
} \
while (0)
/* Returns non-zero if error happened, zero if success. */
#ifdef __sparc32_atomic_do_lock
/* Avoid FUTEX_WAKE_OP if supporting pre-v9 CPUs. */
# define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2) 1
#else
# define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
\
__ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \
FUTEX_WAKE_OP, \
(nr_wake), (nr_wake2), (futexp2), \
FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err); \
})
#endif
static inline int
__attribute__ ((always_inline))
__lll_trylock (int *futex)
{
return atomic_compare_and_exchange_val_24_acq (futex, 1, 0) != 0;
}
#define lll_mutex_trylock(futex) __lll_trylock (&(futex))
static inline int
__attribute__ ((always_inline))
__lll_cond_trylock (int *futex)
{
return atomic_compare_and_exchange_val_24_acq (futex, 2, 0) != 0;
}
#define lll_mutex_cond_trylock(futex) __lll_cond_trylock (&(futex))
static inline int
__attribute__ ((always_inline))
__lll_robust_trylock (int *futex, int id)
{
return atomic_compare_and_exchange_val_acq (futex, id, 0) != 0;
}
#define lll_robust_trylock(futex, id) \
__lll_robust_trylock (&(futex), id)
extern void __lll_lock_wait (int *futex) attribute_hidden;
extern int __lll_robust_lock_wait (int *futex) attribute_hidden;
static inline void
__attribute__ ((always_inline))
__lll_lock (int *futex)
{
int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);
if (__builtin_expect (val != 0, 0))
{
__lll_lock_wait (futex);
}
}
#define lll_mutex_lock(futex) __lll_lock (&(futex))
static inline int
__attribute__ ((always_inline))
__lll_robust_lock (int *futex, int id)
{
int result = 0;
if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
result = __lll_robust_lock_wait (futex);
return result;
}
#define lll_robust_lock(futex, id) \
__lll_robust_lock (&(futex), id)
static inline void
__attribute__ ((always_inline))
__lll_cond_lock (int *futex)
{
int val = atomic_compare_and_exchange_val_24_acq (futex, 2, 0);
if (__builtin_expect (val != 0, 0))
__lll_lock_wait (futex);
}
#define lll_mutex_cond_lock(futex) __lll_cond_lock (&(futex))
#define lll_robust_cond_lock(futex, id) \
__lll_robust_lock (&(futex), (id) | FUTEX_WAITERS)
extern int __lll_timedlock_wait (int *futex, const struct timespec *) attribute_hidden;
extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *) attribute_hidden;
static inline int
__attribute__ ((always_inline))
__lll_timedlock (int *futex, const struct timespec *abstime)
{
int val = atomic_compare_and_exchange_val_24_acq (futex, 1, 0);
int result = 0;
if (__builtin_expect (val != 0, 0))
result = __lll_timedlock_wait (futex, abstime);
return result;
}
#define lll_mutex_timedlock(futex, abstime) \
__lll_timedlock (&(futex), abstime)
static inline int
__attribute__ ((always_inline))
__lll_robust_timedlock (int *futex, const struct timespec *abstime,
int id)
{
int result = 0;
if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0)
result = __lll_robust_timedlock_wait (futex, abstime);
return result;
}
#define lll_robust_timedlock(futex, abstime, id) \
__lll_robust_timedlock (&(futex), abstime, id)
#define lll_mutex_unlock(lock) \
((void) ({ \
int *__futex = &(lock); \
int __val = atomic_exchange_24_rel (__futex, 0); \
if (__builtin_expect (__val > 1, 0)) \
lll_futex_wake (__futex, 1); \
}))
#define lll_robust_unlock(lock) \
((void) ({ \
int *__futex = &(lock); \
int __val = atomic_exchange_rel (__futex, 0); \
if (__builtin_expect (__val & FUTEX_WAITERS, 0)) \
lll_futex_wake (__futex, 1); \
}))
#define lll_mutex_islocked(futex) \
(futex != 0)
/* We have a separate internal lock implementation which is not tied
to binary compatibility. */
/* Type for lock object. */
typedef int lll_lock_t;
/* Initializers for lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
#define lll_trylock(lock) lll_mutex_trylock (lock)
#define lll_lock(lock) lll_mutex_lock (lock)
#define lll_unlock(lock) lll_mutex_unlock (lock)
#define lll_islocked(lock) lll_mutex_islocked (lock)
/* The kernel notifies a process with uses CLONE_CLEARTID via futex
wakeup when the clone terminates. The memory location contains the
thread ID while the clone is running and is reset to zero
afterwards. */
#define lll_wait_tid(tid) \
do \
{ \
__typeof (tid) __tid; \
while ((__tid = (tid)) != 0) \
lll_futex_wait (&(tid), __tid); \
} \
while (0)
extern int __lll_timedwait_tid (int *, const struct timespec *)
attribute_hidden;
#define lll_timedwait_tid(tid, abstime) \
({ \
int __res = 0; \
if ((tid) != 0) \
__res = __lll_timedwait_tid (&(tid), (abstime)); \
__res; \
})
#endif /* lowlevellock.h */
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