diff options
Diffstat (limited to 'lib/libthr/thread/thr_spinlock.c')
| -rw-r--r-- | lib/libthr/thread/thr_spinlock.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/lib/libthr/thread/thr_spinlock.c b/lib/libthr/thread/thr_spinlock.c new file mode 100644 index 0000000..60e9522 --- /dev/null +++ b/lib/libthr/thread/thr_spinlock.c @@ -0,0 +1,179 @@ +/* + * Copyright (c) 2004 Michael Telahun Makonnen <mtm@FreeBSD.Org> + * Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by John Birrell. + * 4. Neither the name of the author nor the names of any co-contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * $FreeBSD$ + * + */ + +#include <sys/types.h> +#include <machine/atomic.h> + +#include <stdlib.h> +#include <stdio.h> +#include <string.h> +#include <sched.h> +#include <pthread.h> +#include <unistd.h> + +#include <libc_private.h> + +#include "thr_private.h" + +#define THR_SPIN_MAGIC 0xdadadada +#define THR_SPIN_UNOWNED (void *)0 +#define MAGIC_TEST_RETURN_ON_FAIL(l) \ + do { \ + if ((l) == NULL || (l)->s_magic != THR_SPIN_MAGIC) \ + return (EINVAL); \ + } while(0) + +__weak_reference(_pthread_spin_destroy, pthread_spin_destroy); +__weak_reference(_pthread_spin_init, pthread_spin_init); +__weak_reference(_pthread_spin_lock, pthread_spin_lock); +__weak_reference(_pthread_spin_trylock, pthread_spin_trylock); +__weak_reference(_pthread_spin_unlock, pthread_spin_unlock); + +int +_pthread_spin_destroy(pthread_spinlock_t *lock) +{ + MAGIC_TEST_RETURN_ON_FAIL((*lock)); + if ((*lock)->s_owner == THR_SPIN_UNOWNED) { + (*lock)->s_magic = 0; + free((*lock)); + *lock = NULL; + return (0); + } + return (EBUSY); +} + +int +_pthread_spin_init(pthread_spinlock_t *lock, int pshared) +{ + struct pthread_spinlock *s; + + if (*lock != NULL) { + if ((*lock)->s_magic == THR_SPIN_MAGIC) + return (EBUSY); + } + s = (struct pthread_spinlock *)malloc(sizeof(struct pthread_spinlock)); + if (s == NULL) + return (ENOMEM); + s->s_magic = THR_SPIN_MAGIC; + s->s_owner = THR_SPIN_UNOWNED; + *lock = s; + return (0); +} + +/* + * If the caller sets nonblocking to 1, this function will return + * immediately without acquiring the lock it is owned by another thread. + * If set to 0, it will keep spinning until it acquires the lock. + */ +int +_pthread_spin_lock(pthread_spinlock_t *lock) +{ + MAGIC_TEST_RETURN_ON_FAIL(*lock); + if ((*lock)->s_owner == curthread) + return (EDEADLK); + while (atomic_cmpset_acq_ptr(&(*lock)->s_owner, THR_SPIN_UNOWNED, + (void *)curthread) != 1) + ; /* SPIN */ + return (0); +} + +int +_pthread_spin_trylock(pthread_spinlock_t *lock) +{ + MAGIC_TEST_RETURN_ON_FAIL(*lock); + if (atomic_cmpset_acq_ptr(&(*lock)->s_owner, THR_SPIN_UNOWNED, + (void *)curthread) == 1) + return (0); + return (EBUSY); +} + +int +_pthread_spin_unlock(pthread_spinlock_t *lock) +{ + MAGIC_TEST_RETURN_ON_FAIL(*lock); + if (atomic_cmpset_rel_ptr(&(*lock)->s_owner, (void *)curthread, + THR_SPIN_UNOWNED) == 1) + return (0); + return (EPERM); +} + +void +_spinunlock(spinlock_t *lck) +{ + if (umtx_unlock((struct umtx *)lck, curthread->thr_id)) + abort(); +} + +/* + * Lock a location for the running thread. Yield to allow other + * threads to run if this thread is blocked because the lock is + * not available. Note that this function does not sleep. It + * assumes that the lock will be available very soon. + */ +void +_spinlock(spinlock_t *lck) +{ + if (umtx_lock((struct umtx *)lck, curthread->thr_id)) + abort(); +} + +int +_spintrylock(spinlock_t *lck) +{ + int error; + + error = umtx_lock((struct umtx *)lck, curthread->thr_id); + if (error != 0 && error != EBUSY) + abort(); + return (error); +} + +/* + * Lock a location for the running thread. Yield to allow other + * threads to run if this thread is blocked because the lock is + * not available. Note that this function does not sleep. It + * assumes that the lock will be available very soon. + * + * This function checks if the running thread has already locked the + * location, warns if this occurs and creates a thread dump before + * returning. + */ +void +_spinlock_debug(spinlock_t *lck, char *fname, int lineno) +{ + if (umtx_lock((struct umtx *)lck, curthread->thr_id)) + abort(); +} |
