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/* Copyright (C) 2003, 2004 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Martin Schwidefsky <schwidefsky@de.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 Library; 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>
#define SYS_futex 238
#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(futex, val) \
({ \
register unsigned long int __r2 asm ("2") = (unsigned long int) (futex); \
register unsigned long int __r3 asm ("3") = FUTEX_WAIT; \
register unsigned long int __r4 asm ("4") = (unsigned long int) (val); \
register unsigned long int __r5 asm ("5") = 0ul; \
register unsigned long __result asm ("2"); \
\
__asm __volatile ("svc %b1" \
: "=d" (__result) \
: "i" (SYS_futex), "0" (__r2), "d" (__r3), \
"d" (__r4), "d" (__r5) \
: "cc", "memory" ); \
__result; \
})
#define lll_futex_timed_wait(futex, val, timespec) \
({ \
register unsigned long int __r2 asm ("2") = (unsigned long int) (futex); \
register unsigned long int __r3 asm ("3") = FUTEX_WAIT; \
register unsigned long int __r4 asm ("4") = (unsigned long int) (val); \
register unsigned long int __r5 asm ("5") = (unsigned long int)(timespec);\
register unsigned long int __result asm ("2"); \
\
__asm __volatile ("svc %b1" \
: "=d" (__result) \
: "i" (SYS_futex), "0" (__r2), "d" (__r3), \
"d" (__r4), "d" (__r5) \
: "cc", "memory" ); \
__result; \
})
#define lll_futex_wake(futex, nr) \
({ \
register unsigned long int __r2 asm ("2") = (unsigned long int) (futex); \
register unsigned long int __r3 asm ("3") = FUTEX_WAKE; \
register unsigned long int __r4 asm ("4") = (unsigned long int) (nr); \
register unsigned long int __result asm ("2"); \
\
__asm __volatile ("svc %b1" \
: "=d" (__result) \
: "i" (SYS_futex), "0" (__r2), "d" (__r3), "d" (__r4) \
: "cc", "memory" ); \
__result; \
})
/* Returns non-zero if error happened, zero if success. */
#define lll_futex_requeue(futex, nr_wake, nr_move, mutex, val) \
({ \
register unsigned long int __r2 asm ("2") = (unsigned long int) (futex); \
register unsigned long int __r3 asm ("3") = FUTEX_CMP_REQUEUE; \
register unsigned long int __r4 asm ("4") = (long int) (nr_wake); \
register unsigned long int __r5 asm ("5") = (long int) (nr_move); \
register unsigned long int __r6 asm ("6") = (unsigned long int) (mutex); \
register unsigned long int __r7 asm ("7") = (int) (mutex); \
register unsigned long __result asm ("2"); \
\
__asm __volatile ("svc %b1" \
: "=d" (__result) \
: "i" (SYS_futex), "0" (__r2), "d" (__r3), \
"d" (__r4), "d" (__r5), "d" (__r6), "d" (__r7) \
: "cc", "memory" ); \
__result > -4096UL; \
})
#define lll_compare_and_swap(futex, oldval, newval, operation) \
do { \
__typeof (futex) __futex = (futex); \
__asm __volatile (" l %1,%0\n" \
"0: " operation "\n" \
" cs %1,%2,%0\n" \
" jl 0b\n" \
"1:" \
: "=Q" (*__futex), "=&d" (oldval), "=&d" (newval) \
: "m" (*__futex) : "cc" ); \
} while (0)
static inline int
__attribute__ ((always_inline))
__lll_mutex_trylock (int *futex)
{
unsigned int old;
__asm __volatile ("cs %0,%3,%1"
: "=d" (old), "=Q" (*futex)
: "0" (0), "d" (1), "m" (*futex) : "cc" );
return old != 0;
}
#define lll_mutex_trylock(futex) __lll_mutex_trylock (&(futex))
static inline int
__attribute__ ((always_inline))
__lll_mutex_cond_trylock (int *futex)
{
unsigned int old;
__asm __volatile ("cs %0,%3,%1"
: "=d" (old), "=Q" (*futex)
: "0" (0), "d" (2), "m" (*futex) : "cc" );
return old != 0;
}
#define lll_mutex_cond_trylock(futex) __lll_mutex_cond_trylock (&(futex))
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 oldval;
int newval = 0;
lll_compare_and_swap (futex, oldval, newval, "slr %2,%2");
if (oldval > 1)
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)
{
*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)
/* We have a separate internal lock implementation which is not tied
to binary compatibility. We can use the lll_mutex_*. */
/* Type for lock object. */
typedef int lll_lock_t;
/* Initializers for lock. */
#define LLL_LOCK_INITIALIZER (0)
#define LLL_LOCK_INITIALIZER_LOCKED (1)
#define lll_trylock(futex) lll_mutex_trylock (futex)
#define lll_lock(futex) lll_mutex_lock (futex)
#define lll_unlock(futex) lll_mutex_unlock (futex)
#define lll_islocked(futex) lll_mutex_islocked (futex)
extern int lll_unlock_wake_cb (int *__futex) attribute_hidden;
/* The states of a lock are:
1 - untaken
0 - taken by one user
<0 - taken by more users */
/* 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. */
static inline void
__attribute__ ((always_inline))
__lll_wait_tid (int *ptid)
{
int tid;
while ((tid = *ptid) != 0)
lll_futex_wait (ptid, tid);
}
#define lll_wait_tid(tid) __lll_wait_tid(&(tid))
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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