/* Copyright (C) 2003 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 #include #include #include #define __NR_futex 394 #define FUTEX_WAIT 0 #define FUTEX_WAKE 1 #define FUTEX_REQUEUE 3 /* 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; \ }) #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ __ret = INTERNAL_SYSCALL (futex, __err, 5, \ (futexp), FUTEX_REQUEUE, (nr_wake), (nr_move), \ (mutex)); \ INTERNAL_SYSCALL_ERROR_P (__ret, __err)? -__ret : __ret; \ }) /* Set *futex to 1 if it is 0, atomically. Returns the old value */ #define __lll_trylock(futex) \ ({ int __oldval, __temp; \ __asm __volatile ( \ "1: ldl_l %[__oldval], %[__mem]\n" \ " lda %[__temp], 1\n" \ " bne %[__oldval], 2f\n" \ " stl_c %[__temp], %[__mem]\n" \ " beq %[__temp], 1b\n" \ __MB \ "2:" \ : [__oldval] "=&r" (__oldval), \ [__temp] "=&r" (__temp) \ : [__mem] "m" (*(futex)) \ : "memory"); \ __oldval; \ }) #define lll_mutex_trylock(lock) __lll_trylock (&(lock)) extern void __lll_lock_wait (int *futex, int val) attribute_hidden; #define lll_mutex_lock(lock) \ (void) ({ \ int *__futex = &(lock); \ int __val = atomic_exchange_and_add (__futex, 1); \ atomic_full_barrier(); \ if (__builtin_expect (__val != 0, 0)) \ __lll_lock_wait (__futex, __val); \ }) #define lll_mutex_cond_lock(lock) \ (void) ({ \ int *__futex = &(lock); \ int __val = atomic_exchange_and_add (__futex, 2); \ atomic_full_barrier(); \ if (__builtin_expect (__val != 0, 0)) \ /* Note, the val + 1 is kind of ugly here. __lll_lock_wait will \ add 1 again. But we added 2 to the futex value so this is the \ right value which will be passed to the kernel. */ \ __lll_lock_wait (__futex, __val + 1); \ }) extern int __lll_timedlock_wait (int *futex, int val, const struct timespec *) attribute_hidden; #define lll_mutex_timedlock(lock, abstime) \ ({ int *__futex = &(lock); \ int __val = atomic_exchange_and_add (__futex, 1); \ atomic_full_barrier(); \ if (__builtin_expect (__val != 0, 0)) \ __val = __lll_timedlock_wait (__futex, __val, (abstime)); \ __val; \ }) #define lll_mutex_unlock(lock) \ ((void) ({ \ int *__futex = &(lock), __val; \ atomic_write_barrier(); \ __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); \ atomic_write_barrier(); \ *__futex = 0; \ atomic_full_barrier(); \ 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 */