/* Copyright (C) 2003, 2004 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 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 __NR_futex 394
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
#define FUTEX_REQUEUE 3
#define FUTEX_CMP_REQUEUE 4
/* Initializer for compatibility lock. */
#define LLL_MUTEX_LOCK_INITIALIZER (0)
#define lll_futex_wait(futexp, val) \
({ \
INTERNAL_SYSCALL_DECL (__err); \
long int __ret; \
__ret = INTERNAL_SYSCALL (futex, __err, 4, \
(futexp), FUTEX_WAIT, (val), 0); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret; \
})
#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)); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __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); \
INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __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); \
})
static inline int __attribute__((always_inline))
__lll_mutex_trylock(int *futex)
{
return atomic_compare_and_exchange_val_acq (futex, 1, 0) != 0;
}
#define lll_mutex_trylock(lock) __lll_mutex_trylock (&(lock))
static inline int __attribute__((always_inline))
__lll_mutex_cond_trylock(int *futex)
{
return atomic_compare_and_exchange_val_acq (futex, 2, 0) != 0;
}
#define lll_mutex_cond_trylock(lock) __lll_mutex_cond_trylock (&(lock))
extern void __lll_lock_wait (int *futex) attribute_hidden;
static inline void __attribute__((always_inline))
__lll_mutex_lock(int *futex)
{
if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
__lll_lock_wait (futex);
}
#define lll_mutex_lock(futex) __lll_mutex_lock (&(futex))
static inline void __attribute__ ((always_inline))
__lll_mutex_cond_lock (int *futex)
{
if (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0)
__lll_lock_wait (futex);
}
#define lll_mutex_cond_lock(futex) __lll_mutex_cond_lock (&(futex))
extern int __lll_timedlock_wait (int *futex, const struct timespec *)
attribute_hidden;
static inline int __attribute__ ((always_inline))
__lll_mutex_timedlock (int *futex, const struct timespec *abstime)
{
int result = 0;
if (atomic_compare_and_exchange_bool_acq (futex, 1, 0) != 0)
result = __lll_timedlock_wait (futex, abstime);
return result;
}
#define lll_mutex_timedlock(futex, abstime) \
__lll_mutex_timedlock (&(futex), abstime)
static inline void __attribute__ ((always_inline))
__lll_mutex_unlock (int *futex)
{
int val = atomic_exchange_rel (futex, 0);
if (__builtin_expect (val > 1, 0))
lll_futex_wake (futex, 1);
}
#define lll_mutex_unlock(futex) __lll_mutex_unlock(&(futex))
static inline void __attribute__ ((always_inline))
__lll_mutex_unlock_force (int *futex)
{
(void) atomic_exchange_rel (futex, 0);
lll_futex_wake (futex, 1);
}
#define lll_mutex_unlock_force(futex) __lll_mutex_unlock_force(&(futex))
#define lll_mutex_islocked(futex) \
(futex != 0)
/* Our internal lock implementation is identical to the binary-compatible
mutex implementation. */
/* 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;
/* The states of a lock are:
0 - untaken
1 - taken by one user
>1 - taken by more users */
#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 which 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; \
})
/* Conditional variable handling. */
extern void __lll_cond_wait (pthread_cond_t *cond)
attribute_hidden;
extern int __lll_cond_timedwait (pthread_cond_t *cond,
const struct timespec *abstime)
attribute_hidden;
extern void __lll_cond_wake (pthread_cond_t *cond)
attribute_hidden;
extern void __lll_cond_broadcast (pthread_cond_t *cond)
attribute_hidden;
#define lll_cond_wait(cond) \
__lll_cond_wait (cond)
#define lll_cond_timedwait(cond, abstime) \
__lll_cond_timedwait (cond, abstime)
#define lll_cond_wake(cond) \
__lll_cond_wake (cond)
#define lll_cond_broadcast(cond) \
__lll_cond_broadcast (cond)
#endif /* lowlevellock.h */