/* Copyright (C) 2003, 2004 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Jakub Jelinek , 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 #include #include #include #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); \ __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)); \ __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); \ }) #ifdef __sparc32_atomic_do_lock #error SPARC < v9 does not support compare and swap which is essential for futex based locking #endif 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(futex) __lll_mutex_trylock (&(futex)) 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(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) { int val = atomic_compare_and_exchange_val_acq (futex, 1, 0); if (__builtin_expect (val != 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) { int val = atomic_compare_and_exchange_val_acq (futex, 2, 0); if (__builtin_expect (val != 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 val = atomic_compare_and_exchange_val_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_mutex_timedlock (&(futex), abstime) #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); \ (void) atomic_exchange_rel (__futex, 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. We can use the lll_mutex_*. */ /* Type for lock object. */ typedef int lll_lock_t; extern int lll_unlock_wake_cb (int *__futex) attribute_hidden; /* 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) /* 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; \ }) /* 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 */