diff options
Diffstat (limited to 'c/src/lib/libbsp/unix/posix/shmsupp/lock.c')
-rw-r--r-- | c/src/lib/libbsp/unix/posix/shmsupp/lock.c | 72 |
1 files changed, 72 insertions, 0 deletions
diff --git a/c/src/lib/libbsp/unix/posix/shmsupp/lock.c b/c/src/lib/libbsp/unix/posix/shmsupp/lock.c new file mode 100644 index 0000000000..3de04e6082 --- /dev/null +++ b/c/src/lib/libbsp/unix/posix/shmsupp/lock.c @@ -0,0 +1,72 @@ +/* Shared Memory Lock Routines + * + * This shared memory locked queue support routine need to be + * able to lock the specified locked queue. Interrupts are + * disabled while the queue is locked to prevent preemption + * and deadlock when two tasks poll for the same lock. + * previous level. + * + * COPYRIGHT (c) 1989-1997. + * On-Line Applications Research Corporation (OAR). + * Copyright assigned to U.S. Government, 1994. + * + * The license and distribution terms for this file may in + * the file LICENSE in this distribution or at + * http://www.OARcorp.com/rtems/license.html. + * + * $Id$ + */ + +#include <bsp.h> +#include <shm.h> + +/* + * Shm_Initialize_lock + * + * Initialize the lock for the specified locked queue. + */ + +void Shm_Initialize_lock( + Shm_Locked_queue_Control *lq_cb +) +{ + lq_cb->lock = lq_cb - Shm_Locked_queues; +} + +/* Shm_Lock( &lq_cb ) + * + * This shared memory locked queue support routine locks the + * specified locked queue. It disables interrupts to prevent + * a deadlock condition. + */ + +void Shm_Lock( + Shm_Locked_queue_Control *lq_cb +) +{ + rtems_unsigned32 isr_level; + + rtems_interrupt_disable( isr_level ); + + Shm_isrstat = isr_level; + + _CPU_SHM_Lock( lq_cb->lock ); +} + +/* + * Shm_Unlock + * + * Unlock the lock for the specified locked queue. + */ + +void Shm_Unlock( + Shm_Locked_queue_Control *lq_cb +) +{ + rtems_unsigned32 isr_level; + + _CPU_SHM_Unlock( lq_cb->lock ); + + isr_level = Shm_isrstat; + rtems_interrupt_enable( isr_level ); +} |