diff options
Diffstat (limited to 'arch/alpha/kernel/semaphore.c')
| -rw-r--r-- | arch/alpha/kernel/semaphore.c | 224 |
1 files changed, 0 insertions, 224 deletions
diff --git a/arch/alpha/kernel/semaphore.c b/arch/alpha/kernel/semaphore.c deleted file mode 100644 index 8d2982aa1b8d..000000000000 --- a/arch/alpha/kernel/semaphore.c +++ /dev/null @@ -1,224 +0,0 @@ -/* - * Alpha semaphore implementation. - * - * (C) Copyright 1996 Linus Torvalds - * (C) Copyright 1999, 2000 Richard Henderson - */ - -#include <linux/errno.h> -#include <linux/sched.h> -#include <linux/init.h> - -/* - * This is basically the PPC semaphore scheme ported to use - * the Alpha ll/sc sequences, so see the PPC code for - * credits. - */ - -/* - * Atomically update sem->count. - * This does the equivalent of the following: - * - * old_count = sem->count; - * tmp = MAX(old_count, 0) + incr; - * sem->count = tmp; - * return old_count; - */ -static inline int __sem_update_count(struct semaphore *sem, int incr) -{ - long old_count, tmp = 0; - - __asm__ __volatile__( - "1: ldl_l %0,%2\n" - " cmovgt %0,%0,%1\n" - " addl %1,%3,%1\n" - " stl_c %1,%2\n" - " beq %1,2f\n" - " mb\n" - ".subsection 2\n" - "2: br 1b\n" - ".previous" - : "=&r" (old_count), "=&r" (tmp), "=m" (sem->count) - : "Ir" (incr), "1" (tmp), "m" (sem->count)); - - return old_count; -} - -/* - * Perform the "down" function. Return zero for semaphore acquired, - * return negative for signalled out of the function. - * - * If called from down, the return is ignored and the wait loop is - * not interruptible. This means that a task waiting on a semaphore - * using "down()" cannot be killed until someone does an "up()" on - * the semaphore. - * - * If called from down_interruptible, the return value gets checked - * upon return. If the return value is negative then the task continues - * with the negative value in the return register (it can be tested by - * the caller). - * - * Either form may be used in conjunction with "up()". - */ - -void __sched -__down_failed(struct semaphore *sem) -{ - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait, tsk); - -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down failed(%p)\n", - tsk->comm, task_pid_nr(tsk), sem); -#endif - - tsk->state = TASK_UNINTERRUPTIBLE; - wmb(); - add_wait_queue_exclusive(&sem->wait, &wait); - - /* - * Try to get the semaphore. If the count is > 0, then we've - * got the semaphore; we decrement count and exit the loop. - * If the count is 0 or negative, we set it to -1, indicating - * that we are asleep, and then sleep. - */ - while (__sem_update_count(sem, -1) <= 0) { - schedule(); - set_task_state(tsk, TASK_UNINTERRUPTIBLE); - } - remove_wait_queue(&sem->wait, &wait); - tsk->state = TASK_RUNNING; - - /* - * If there are any more sleepers, wake one of them up so - * that it can either get the semaphore, or set count to -1 - * indicating that there are still processes sleeping. - */ - wake_up(&sem->wait); - -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down acquired(%p)\n", - tsk->comm, task_pid_nr(tsk), sem); -#endif -} - -int __sched -__down_failed_interruptible(struct semaphore *sem) -{ - struct task_struct *tsk = current; - DECLARE_WAITQUEUE(wait, tsk); - long ret = 0; - -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down failed(%p)\n", - tsk->comm, task_pid_nr(tsk), sem); -#endif - - tsk->state = TASK_INTERRUPTIBLE; - wmb(); - add_wait_queue_exclusive(&sem->wait, &wait); - - while (__sem_update_count(sem, -1) <= 0) { - if (signal_pending(current)) { - /* - * A signal is pending - give up trying. - * Set sem->count to 0 if it is negative, - * since we are no longer sleeping. - */ - __sem_update_count(sem, 0); - ret = -EINTR; - break; - } - schedule(); - set_task_state(tsk, TASK_INTERRUPTIBLE); - } - - remove_wait_queue(&sem->wait, &wait); - tsk->state = TASK_RUNNING; - wake_up(&sem->wait); - -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down %s(%p)\n", - current->comm, task_pid_nr(current), - (ret < 0 ? "interrupted" : "acquired"), sem); -#endif - return ret; -} - -void -__up_wakeup(struct semaphore *sem) -{ - /* - * Note that we incremented count in up() before we came here, - * but that was ineffective since the result was <= 0, and - * any negative value of count is equivalent to 0. - * This ends up setting count to 1, unless count is now > 0 - * (i.e. because some other cpu has called up() in the meantime), - * in which case we just increment count. - */ - __sem_update_count(sem, 1); - wake_up(&sem->wait); -} - -void __sched -down(struct semaphore *sem) -{ -#ifdef WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); -#endif -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down(%p) <count=%d> from %p\n", - current->comm, task_pid_nr(current), sem, - atomic_read(&sem->count), __builtin_return_address(0)); -#endif - __down(sem); -} - -int __sched -down_interruptible(struct semaphore *sem) -{ -#ifdef WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); -#endif -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down(%p) <count=%d> from %p\n", - current->comm, task_pid_nr(current), sem, - atomic_read(&sem->count), __builtin_return_address(0)); -#endif - return __down_interruptible(sem); -} - -int -down_trylock(struct semaphore *sem) -{ - int ret; - -#ifdef WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); -#endif - - ret = __down_trylock(sem); - -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): down_trylock %s from %p\n", - current->comm, task_pid_nr(current), - ret ? "failed" : "acquired", - __builtin_return_address(0)); -#endif - - return ret; -} - -void -up(struct semaphore *sem) -{ -#ifdef WAITQUEUE_DEBUG - CHECK_MAGIC(sem->__magic); -#endif -#ifdef CONFIG_DEBUG_SEMAPHORE - printk("%s(%d): up(%p) <count=%d> from %p\n", - current->comm, task_pid_nr(current), sem, - atomic_read(&sem->count), __builtin_return_address(0)); -#endif - __up(sem); -} |