/* Copyright (C) 2005, 2006 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 #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) /* 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; \ }) #define lll_robust_mutex_dead(futexv) \ do \ { \ int *__futexp = &(futexv); \ atomic_or (__futexp, FUTEX_OWNER_DIED); \ lll_futex_wake (__futexp, 1); \ } \ while (0) /* 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)); \ __ret; \ }) /* Returns non-zero if error happened, zero if success. */ #define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2) \ ({ \ INTERNAL_SYSCALL_DECL (__err); \ long int __ret; \ __ret = INTERNAL_SYSCALL (futex, __err, 6, \ (futexp), FUTEX_WAKE_OP, (nr_wake), \ (nr_wake2), (futexp2), \ FUTEX_OP_CLEAR_WAKE_IF_GT_ONE); \ __ret; \ }) static inline int __attribute__((always_inline)) __lll_mutex_trylock (int *futex) { int flag = 1, old; asm volatile ( "\tswp %[old], %[flag], [%[futex]] @ try to take the lock\n" "\tcmp %[old], #1 @ check old lock value\n" "\tmovlo %[flag], #0 @ if we got it, return 0\n" "\tswphi %[flag], %[old], [%[futex]] @ if it was contested,\n" " @ restore the contested flag,\n" " @ and check whether that won." : [futex] "+&r" (futex), [flag] "+&r" (flag), [old] "=&r" (old) : : "memory" ); return flag; } #define lll_mutex_trylock(lock) __lll_mutex_trylock (&(lock)) static inline int __attribute__((always_inline)) __lll_mutex_cond_trylock (int *futex) { int flag = 2, old; asm volatile ( "\tswp %[old], %[flag], [%[futex]] @ try to take the lock\n" "\tcmp %[old], #1 @ check old lock value\n" "\tmovlo %[flag], #0 @ if we got it, return 0\n" "\tswphi %[flag], %[old], [%[futex]] @ if it was contested,\n" " @ restore the contested flag,\n" " @ and check whether that won." : [futex] "+&r" (futex), [flag] "+&r" (flag), [old] "=&r" (old) : : "memory" ); return flag; } #define lll_mutex_cond_trylock(lock) __lll_mutex_cond_trylock (&(lock)) static inline int __attribute__((always_inline)) __lll_robust_mutex_trylock(int *futex, int id) { return atomic_compare_and_exchange_val_acq (futex, id, 0) != 0; } #define lll_robust_mutex_trylock(lock, id) \ __lll_robust_mutex_trylock (&(lock), id) extern int __lll_robust_lock_wait (int *futex) attribute_hidden; static inline void __attribute__((always_inline)) __lll_mutex_lock (int *futex) { int val = atomic_exchange_acq (futex, 1); if (__builtin_expect (val != 0, 0)) { while (atomic_exchange_acq (futex, 2) != 0) lll_futex_wait (futex, 2); } } #define lll_mutex_lock(futex) __lll_mutex_lock (&(futex)) static inline int __attribute__ ((always_inline)) __lll_robust_mutex_lock (int *futex, int id) { int result = 0; if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0) result = __lll_robust_lock_wait (futex); return result; } #define lll_robust_mutex_lock(futex, id) \ __lll_robust_mutex_lock (&(futex), id) static inline void __attribute__ ((always_inline)) __lll_mutex_cond_lock (int *futex) { int val = atomic_exchange_acq (futex, 2); if (__builtin_expect (val != 0, 0)) { while (atomic_exchange_acq (futex, 2) != 0) lll_futex_wait (futex, 2); } } #define lll_mutex_cond_lock(futex) __lll_mutex_cond_lock (&(futex)) #define lll_robust_mutex_cond_lock(futex, id) \ __lll_robust_mutex_lock (&(futex), (id) | FUTEX_WAITERS) extern int __lll_timedlock_wait (int *futex, const struct timespec *) attribute_hidden; extern int __lll_robust_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; int val = atomic_exchange_acq (futex, 1); 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) static inline int __attribute__ ((always_inline)) __lll_robust_mutex_timedlock (int *futex, const struct timespec *abstime, int id) { int result = 0; if (atomic_compare_and_exchange_bool_acq (futex, id, 0) != 0) result = __lll_robust_timedlock_wait (futex, abstime); return result; } #define lll_robust_mutex_timedlock(futex, abstime, id) \ __lll_robust_mutex_timedlock (&(futex), abstime, id) static inline void __attribute__ ((always_inline)) __lll_mutex_unlock (int *futex) { int val = atomic_exchange_rel (futex, 0); if (__builtin_expect (val > 1, 0)) lll_futex_wake (futex, 1); } #define lll_mutex_unlock(futex) __lll_mutex_unlock(&(futex)) static inline void __attribute__ ((always_inline)) __lll_robust_mutex_unlock (int *futex, int mask) { int val = atomic_exchange_rel (futex, 0); if (__builtin_expect (val & mask, 0)) lll_futex_wake (futex, 1); } #define lll_robust_mutex_unlock(futex) \ __lll_robust_mutex_unlock(&(futex), FUTEX_WAITERS) static inline void __attribute__ ((always_inline)) __lll_mutex_unlock_force (int *futex) { (void) atomic_exchange_rel (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) /* 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 */