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/* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Paul Mackerras <paulus@au.ibm.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>
#ifndef __NR_futex
# define __NR_futex 221
#endif
#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); \
})
#ifdef UP
# define __lll_acq_instr ""
# define __lll_rel_instr ""
#else
# define __lll_acq_instr "isync"
# define __lll_rel_instr "sync"
#endif
/* Set *futex to 1 if it is 0, atomically. Returns the old value */
#define __lll_trylock(futex) \
({ int __val; \
__asm __volatile ("1: lwarx %0,0,%2\n" \
" cmpwi 0,%0,0\n" \
" bne 2f\n" \
" stwcx. %3,0,%2\n" \
" bne- 1b\n" \
"2: " __lll_acq_instr \
: "=&r" (__val), "=m" (*futex) \
: "r" (futex), "r" (1), "m" (*futex) \
: "cr0", "memory"); \
__val; \
})
#define lll_mutex_trylock(lock) __lll_trylock (&(lock))
/* Set *futex to 2 if it is 0, atomically. Returns the old value */
#define __lll_cond_trylock(futex) \
({ int __val; \
__asm __volatile ("1: lwarx %0,0,%2\n" \
" cmpwi 0,%0,0\n" \
" bne 2f\n" \
" stwcx. %3,0,%2\n" \
" bne- 1b\n" \
"2: " __lll_acq_instr \
: "=&r" (__val), "=m" (*futex) \
: "r" (futex), "r" (2), "m" (*futex) \
: "cr0", "memory"); \
__val; \
})
#define lll_mutex_cond_trylock(lock) __lll_cond_trylock (&(lock))
extern void __lll_lock_wait (int *futex) attribute_hidden;
#define lll_mutex_lock(lock) \
(void) ({ \
int *__futex = &(lock); \
if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 1, 0),\
0) != 0) \
__lll_lock_wait (__futex); \
})
#define lll_mutex_cond_lock(lock) \
(void) ({ \
int *__futex = &(lock); \
if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 2, 0),\
0) != 0) \
__lll_lock_wait (__futex); \
})
extern int __lll_timedlock_wait
(int *futex, const struct timespec *) attribute_hidden;
#define lll_mutex_timedlock(lock, abstime) \
({ \
int *__futex = &(lock); \
int __val = 0; \
if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, 1, 0),\
0) != 0) \
__val = __lll_timedlock_wait (__futex, abstime); \
__val; \
})
#define lll_mutex_unlock(lock) \
((void) ({ \
int *__futex = &(lock); \
int __val = atomic_exchange_rel (__futex, 0); \
if (__builtin_expect (__val > 1, 0)) \
lll_futex_wake (__futex, 1); \
}))
#define lll_mutex_unlock_force(lock) \
((void) ({ \
int *__futex = &(lock); \
*__futex = 0; \
__asm __volatile (__lll_rel_instr ::: "memory"); \
lll_futex_wake (__futex, 1); \
}))
#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 */
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