diff options
Diffstat (limited to 'target/linux/ubicom32/files/arch/ubicom32/kernel/semaphore.c')
| -rw-r--r-- | target/linux/ubicom32/files/arch/ubicom32/kernel/semaphore.c | 159 |
1 files changed, 0 insertions, 159 deletions
diff --git a/target/linux/ubicom32/files/arch/ubicom32/kernel/semaphore.c b/target/linux/ubicom32/files/arch/ubicom32/kernel/semaphore.c deleted file mode 100644 index d996ac2b30..0000000000 --- a/target/linux/ubicom32/files/arch/ubicom32/kernel/semaphore.c +++ /dev/null @@ -1,159 +0,0 @@ -/* - * arch/ubicom32/kernel/semaphore.c - * Ubicom32 architecture semaphore implementation. - * - * (C) Copyright 2009, Ubicom, Inc. - * - * This file is part of the Ubicom32 Linux Kernel Port. - * - * The Ubicom32 Linux Kernel Port is free software: you can redistribute - * it and/or modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation, either version 2 of the - * License, or (at your option) any later version. - * - * The Ubicom32 Linux Kernel Port 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 General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * along with the Ubicom32 Linux Kernel Port. If not, - * see <http://www.gnu.org/licenses/>. - * - * Ubicom32 implementation derived from (with many thanks): - * arch/m68knommu - * arch/blackfin - * arch/parisc - */ -/* - * Generic semaphore code. Buyer beware. Do your own - * specific changes in <asm/semaphore-helper.h> - */ - -#include <linux/sched.h> -#include <linux/err.h> -#include <linux/init.h> -#include <asm/semaphore-helper.h> - -#ifndef CONFIG_RMW_INSNS -spinlock_t semaphore_wake_lock; -#endif - -/* - * Semaphores are implemented using a two-way counter: - * The "count" variable is decremented for each process - * that tries to sleep, while the "waking" variable is - * incremented when the "up()" code goes to wake up waiting - * processes. - * - * Notably, the inline "up()" and "down()" functions can - * efficiently test if they need to do any extra work (up - * needs to do something only if count was negative before - * the increment operation. - * - * waking_non_zero() (from asm/semaphore.h) must execute - * atomically. - * - * When __up() is called, the count was negative before - * incrementing it, and we need to wake up somebody. - * - * This routine adds one to the count of processes that need to - * wake up and exit. ALL waiting processes actually wake up but - * only the one that gets to the "waking" field first will gate - * through and acquire the semaphore. The others will go back - * to sleep. - * - * Note that these functions are only called when there is - * contention on the lock, and as such all this is the - * "non-critical" part of the whole semaphore business. The - * critical part is the inline stuff in <asm/semaphore.h> - * where we want to avoid any extra jumps and calls. - */ -void __up(struct semaphore *sem) -{ - wake_one_more(sem); - wake_up(&sem->wait); -} - -/* - * 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()". - * - */ - - -#define DOWN_HEAD(task_state) \ - \ - \ - current->state = (task_state); \ - add_wait_queue(&sem->wait, &wait); \ - \ - /* \ - * Ok, we're set up. sem->count is known to be less than zero \ - * so we must wait. \ - * \ - * We can let go the lock for purposes of waiting. \ - * We re-acquire it after awaking so as to protect \ - * all semaphore operations. \ - * \ - * If "up()" is called before we call waking_non_zero() then \ - * we will catch it right away. If it is called later then \ - * we will have to go through a wakeup cycle to catch it. \ - * \ - * Multiple waiters contend for the semaphore lock to see \ - * who gets to gate through and who has to wait some more. \ - */ \ - for (;;) { - -#define DOWN_TAIL(task_state) \ - current->state = (task_state); \ - } \ - current->state = TASK_RUNNING; \ - remove_wait_queue(&sem->wait, &wait); - -void __sched __down(struct semaphore *sem) -{ - DECLARE_WAITQUEUE(wait, current); - - DOWN_HEAD(TASK_UNINTERRUPTIBLE) - if (waking_non_zero(sem)) - break; - schedule(); - DOWN_TAIL(TASK_UNINTERRUPTIBLE) -} - -int __sched __down_interruptible(struct semaphore *sem) -{ - DECLARE_WAITQUEUE(wait, current); - int ret = 0; - - DOWN_HEAD(TASK_INTERRUPTIBLE) - - ret = waking_non_zero_interruptible(sem, current); - if (ret) { - if (ret == 1) - /* ret != 0 only if we get interrupted -arca */ - ret = 0; - break; - } - schedule(); - DOWN_TAIL(TASK_INTERRUPTIBLE) - return ret; -} - -int __down_trylock(struct semaphore *sem) -{ - return waking_non_zero_trylock(sem); -} |