diff options
Diffstat (limited to 'linuxthreads/spinlock.h')
| -rw-r--r-- | linuxthreads/spinlock.h | 218 |
1 files changed, 0 insertions, 218 deletions
diff --git a/linuxthreads/spinlock.h b/linuxthreads/spinlock.h deleted file mode 100644 index ff96fc3360..0000000000 --- a/linuxthreads/spinlock.h +++ /dev/null @@ -1,218 +0,0 @@ -/* Linuxthreads - a simple clone()-based implementation of Posix */ -/* threads for Linux. */ -/* Copyright (C) 1998 Xavier Leroy (Xavier.Leroy@inria.fr) */ -/* */ -/* This program is free software; you can redistribute it and/or */ -/* modify it under the terms of the GNU Library General Public License */ -/* as published by the Free Software Foundation; either version 2 */ -/* of the License, or (at your option) any later version. */ -/* */ -/* This program 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 Library General Public License for more details. */ - -#include <bits/initspin.h> - - -/* There are 2 compare and swap synchronization primitives with - different semantics: - - 1. compare_and_swap, which has acquire semantics (i.e. it - completes befor subsequent writes.) - 2. compare_and_swap_with_release_semantics, which has release - semantics (it completes after previous writes.) - - For those platforms on which they are the same. HAS_COMPARE_AND_SWAP - should be defined. For those platforms on which they are different, - HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS has to be defined. */ - -#ifndef HAS_COMPARE_AND_SWAP -#ifdef HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS -#define HAS_COMPARE_AND_SWAP -#endif -#endif - -#if defined(TEST_FOR_COMPARE_AND_SWAP) - -extern int __pthread_has_cas; -extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval, - int * spinlock); - -static inline int compare_and_swap(long * ptr, long oldval, long newval, - int * spinlock) -{ - if (__builtin_expect (__pthread_has_cas, 1)) - return __compare_and_swap(ptr, oldval, newval); - else - return __pthread_compare_and_swap(ptr, oldval, newval, spinlock); -} - -#elif defined(HAS_COMPARE_AND_SWAP) - -#ifdef IMPLEMENT_TAS_WITH_CAS -#define testandset(p) !__compare_and_swap((long int *) p, 0, 1) -#endif - -#ifdef HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS - -static inline int -compare_and_swap_with_release_semantics (long * ptr, long oldval, - long newval, int * spinlock) -{ - return __compare_and_swap_with_release_semantics (ptr, oldval, - newval); -} - -#endif - -static inline int compare_and_swap(long * ptr, long oldval, long newval, - int * spinlock) -{ - return __compare_and_swap(ptr, oldval, newval); -} - -#else - -extern int __pthread_compare_and_swap(long * ptr, long oldval, long newval, - int * spinlock); - -static inline int compare_and_swap(long * ptr, long oldval, long newval, - int * spinlock) -{ - return __pthread_compare_and_swap(ptr, oldval, newval, spinlock); -} - -#endif - -#ifndef HAS_COMPARE_AND_SWAP_WITH_RELEASE_SEMANTICS -#define compare_and_swap_with_release_semantics compare_and_swap -#define __compare_and_swap_with_release_semantics __compare_and_swap -#endif - -/* Internal locks */ - -extern void internal_function __pthread_lock(struct _pthread_fastlock * lock, - pthread_descr self); -extern int __pthread_unlock(struct _pthread_fastlock *lock); - -static inline void __pthread_init_lock(struct _pthread_fastlock * lock) -{ - lock->__status = 0; - lock->__spinlock = __LT_SPINLOCK_INIT; -} - -static inline int __pthread_trylock (struct _pthread_fastlock * lock) -{ -#if defined TEST_FOR_COMPARE_AND_SWAP - if (!__pthread_has_cas) -#endif -#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP - { - return (testandset(&lock->__spinlock) ? EBUSY : 0); - } -#endif - -#if defined HAS_COMPARE_AND_SWAP - do { - if (lock->__status != 0) return EBUSY; - } while(! __compare_and_swap(&lock->__status, 0, 1)); - return 0; -#endif -} - -/* Variation of internal lock used for pthread_mutex_t, supporting - timed-out waits. Warning: do not mix these operations with the above ones - over the same lock object! */ - -extern void __pthread_alt_lock(struct _pthread_fastlock * lock, - pthread_descr self); - -extern int __pthread_alt_timedlock(struct _pthread_fastlock * lock, - pthread_descr self, const struct timespec *abstime); - -extern void __pthread_alt_unlock(struct _pthread_fastlock *lock); - -static inline void __pthread_alt_init_lock(struct _pthread_fastlock * lock) -{ - lock->__status = 0; - lock->__spinlock = __LT_SPINLOCK_INIT; -} - -static inline int __pthread_alt_trylock (struct _pthread_fastlock * lock) -{ -#if defined TEST_FOR_COMPARE_AND_SWAP - if (!__pthread_has_cas) -#endif -#if !defined HAS_COMPARE_AND_SWAP || defined TEST_FOR_COMPARE_AND_SWAP - { - int res = EBUSY; - - if (testandset(&lock->__spinlock) == 0) - { - if (lock->__status == 0) - { - lock->__status = 1; - WRITE_MEMORY_BARRIER(); - res = 0; - } - lock->__spinlock = __LT_SPINLOCK_INIT; - } - return res; - } -#endif - -#if defined HAS_COMPARE_AND_SWAP - do { - if (lock->__status != 0) return EBUSY; - } while(! compare_and_swap(&lock->__status, 0, 1, &lock->__spinlock)); - return 0; -#endif -} - -/* Operations on pthread_atomic, which is defined in internals.h */ - -static inline long atomic_increment(struct pthread_atomic *pa) -{ - long oldval; - - do { - oldval = pa->p_count; - } while (!compare_and_swap(&pa->p_count, oldval, oldval + 1, &pa->p_spinlock)); - - return oldval; -} - - -static inline long atomic_decrement(struct pthread_atomic *pa) -{ - long oldval; - - do { - oldval = pa->p_count; - } while (!compare_and_swap(&pa->p_count, oldval, oldval - 1, &pa->p_spinlock)); - - return oldval; -} - - -static inline __attribute__((always_inline)) void -__pthread_set_own_extricate_if (pthread_descr self, pthread_extricate_if *peif) -{ - /* Only store a non-null peif if the thread has cancellation enabled. - Otherwise pthread_cancel will unconditionally call the extricate handler, - and restart the thread giving rise to forbidden spurious wakeups. */ - if (peif == NULL - || THREAD_GETMEM(self, p_cancelstate) == PTHREAD_CANCEL_ENABLE) - { - /* If we are removing the extricate interface, we need to synchronize - against pthread_cancel so that it does not continue with a pointer - to a deallocated pthread_extricate_if struct! The thread lock - is (ab)used for this synchronization purpose. */ - if (peif == NULL) - __pthread_lock (THREAD_GETMEM(self, p_lock), self); - THREAD_SETMEM(self, p_extricate, peif); - if (peif == NULL) - __pthread_unlock (THREAD_GETMEM(self, p_lock)); - } -} |