/* Copyright (C) 2005, 2006, 2007, 2008, 2009 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 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 #include #include #include #include #include #define FUTEX_WAIT 0 #define FUTEX_WAKE 1 #define FUTEX_REQUEUE 3 #define FUTEX_CMP_REQUEUE 4 #define FUTEX_WAKE_OP 5 #define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE ((4 << 24) | 1) #define FUTEX_LOCK_PI 6 #define FUTEX_UNLOCK_PI 7 #define FUTEX_TRYLOCK_PI 8 #define FUTEX_WAIT_BITSET 9 #define FUTEX_WAKE_BITSET 10 #define FUTEX_PRIVATE_FLAG 128 #define FUTEX_CLOCK_REALTIME 256 #define FUTEX_BITSET_MATCH_ANY 0xffffffff /* Values for 'private' parameter of locking macros. Yes, the definition seems to be backwards. But it is not. The bit will be reversed before passing to the system call. */ #define LLL_PRIVATE 0 #define LLL_SHARED FUTEX_PRIVATE_FLAG #if !defined NOT_IN_libc || defined IS_IN_rtld /* In libc.so or ld.so all futexes are private. */ # ifdef __ASSUME_PRIVATE_FUTEX # define __lll_private_flag(fl, private) \ ((fl) | FUTEX_PRIVATE_FLAG) # else # define __lll_private_flag(fl, private) \ ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) # endif #else # ifdef __ASSUME_PRIVATE_FUTEX # define __lll_private_flag(fl, private) \ (((fl) | FUTEX_PRIVATE_FLAG) ^ (private)) # else # define __lll_private_flag(fl, private) \ (__builtin_constant_p (private) \ ? ((private) == 0 \ ? ((fl) | THREAD_GETMEM (THREAD_SELF, header.private_futex)) \ : (fl)) \ : ((fl) | (((private) ^ FUTEX_PRIVATE_FLAG) \ & THREAD_GETMEM (THREAD_SELF, header.private_futex)))) # endif #endif #define lll_futex_wait(futexp, val, private) \ lll_futex_timed_wait(futexp, val, NULL, private) #define lll_futex_timed_wait(futexp, val, timespec, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \ __lll_private_flag (FUTEX_WAIT, private), \ (val), (timespec)); \ __ret; \ }) #define lll_futex_wake(futexp, nr, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ __ret = INTERNAL_SYSCALL (futex, __err, 4, (futexp), \ __lll_private_flag (FUTEX_WAKE, private), \ (nr), 0); \ __ret; \ }) #define lll_robust_dead(futexv, private) \ do \ { \ int *__futexp = &(futexv); \ atomic_or (__futexp, FUTEX_OWNER_DIED); \ lll_futex_wake (__futexp, 1, private); \ } \ while (0) /* Returns non-zero if error happened, zero if success. */ #define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ __lll_private_flag (FUTEX_CMP_REQUEUE, private),\ (nr_wake), (nr_move), (mutex), (val)); \ __ret; \ }) /* Returns non-zero if error happened, zero if success. */ #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ __ret = INTERNAL_SYSCALL (futex, __err, 6, (futexp), \ __lll_private_flag (FUTEX_WAKE_OP, private), \ (nr_wake), (nr_wake2), (futexp2), \ FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \ __ret; \ }) #define lll_trylock(lock) \ atomic_compare_and_exchange_val_acq(&(lock), 1, 0) #define lll_cond_trylock(lock) \ atomic_compare_and_exchange_val_acq(&(lock), 2, 0) #define __lll_robust_trylock(futex, id) \ (atomic_compare_and_exchange_val_acq (futex, id, 0) != 0) #define lll_robust_trylock(lock, id) \ __lll_robust_trylock (&(lock), id) extern void __lll_lock_wait_private (int *futex) attribute_hidden; extern void __lll_lock_wait (int *futex, int private) attribute_hidden; extern int __lll_robust_lock_wait (int *futex, int private) attribute_hidden; #define __lll_lock(futex, private) \ ((void) ({ \ int *__futex = (futex); \ if (__builtin_expect (atomic_compare_and_exchange_val_acq (__futex, \ 1, 0), 0)) \ { \ if (__builtin_constant_p (private) && (private) == LLL_PRIVATE) \ __lll_lock_wait_private (__futex); \ else \ __lll_lock_wait (__futex, private); \ } \ })) #define lll_lock(futex, private) __lll_lock (&(futex), private) #define __lll_robust_lock(futex, id, private) \ ({ \ int *__futex = (futex); \ int __val = 0; \ \ if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \ 0), 0)) \ __val = __lll_robust_lock_wait (__futex, private); \ __val; \ }) #define lll_robust_lock(futex, id, private) \ __lll_robust_lock (&(futex), id, private) #define __lll_cond_lock(futex, private) \ ((void) ({ \ int *__futex = (futex); \ if (__builtin_expect (atomic_exchange_acq (__futex, 2), 0)) \ __lll_lock_wait (__futex, private); \ })) #define lll_cond_lock(futex, private) __lll_cond_lock (&(futex), private) #define lll_robust_cond_lock(futex, id, private) \ __lll_robust_lock (&(futex), (id) | FUTEX_WAITERS, private) extern int __lll_timedlock_wait (int *futex, const struct timespec *, int private) attribute_hidden; extern int __lll_robust_timedlock_wait (int *futex, const struct timespec *, int private) attribute_hidden; #define __lll_timedlock(futex, abstime, private) \ ({ \ int *__futex = (futex); \ int __val = 0; \ \ if (__builtin_expect (atomic_exchange_acq (__futex, 1), 0)) \ __val = __lll_timedlock_wait (__futex, abstime, private); \ __val; \ }) #define lll_timedlock(futex, abstime, private) \ __lll_timedlock (&(futex), abstime, private) #define __lll_robust_timedlock(futex, abstime, id, private) \ ({ \ int *__futex = (futex); \ int __val = 0; \ \ if (__builtin_expect (atomic_compare_and_exchange_bool_acq (__futex, id, \ 0), 0)) \ __val = __lll_robust_timedlock_wait (__futex, abstime, private); \ __val; \ }) #define lll_robust_timedlock(futex, abstime, id, private) \ __lll_robust_timedlock (&(futex), abstime, id, private) #define __lll_unlock(futex, private) \ (void) \ ({ int *__futex = (futex); \ int __oldval = atomic_exchange_rel (__futex, 0); \ if (__builtin_expect (__oldval > 1, 0)) \ lll_futex_wake (__futex, 1, private); \ }) #define lll_unlock(futex, private) __lll_unlock(&(futex), private) #define __lll_robust_unlock(futex, private) \ (void) \ ({ int *__futex = (futex); \ int __oldval = atomic_exchange_rel (__futex, 0); \ if (__builtin_expect (__oldval & FUTEX_WAITERS, 0)) \ lll_futex_wake (__futex, 1, private); \ }) #define lll_robust_unlock(futex, private) \ __lll_robust_unlock(&(futex), private) #define lll_islocked(futex) \ (futex != 0) /* Our internal lock implementation is identical to the binary-compatible mutex implementation. */ /* Initializers for lock. */ #define LLL_LOCK_INITIALIZER (0) #define LLL_LOCK_INITIALIZER_LOCKED (1) /* The states of a lock are: 0 - untaken 1 - taken by one user >1 - taken by more users */ /* 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, LLL_SHARED);\ } 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; \ }) #endif /* lowlevellock.h */