154 строки
3.5 KiB
C
154 строки
3.5 KiB
C
#ifndef _M68K_SEMAPHORE_H
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#define _M68K_SEMAPHORE_H
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#define RW_LOCK_BIAS 0x01000000
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#ifndef __ASSEMBLY__
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#include <linux/linkage.h>
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#include <linux/wait.h>
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#include <linux/spinlock.h>
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#include <linux/rwsem.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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/*
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* Interrupt-safe semaphores..
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*
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* (C) Copyright 1996 Linus Torvalds
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*
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* m68k version by Andreas Schwab
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*/
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struct semaphore {
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atomic_t count;
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atomic_t waking;
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wait_queue_head_t wait;
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};
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#define __SEMAPHORE_INITIALIZER(name, n) \
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{ \
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.count = ATOMIC_INIT(n), \
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.waking = ATOMIC_INIT(0), \
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.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
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}
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#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
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struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
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#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
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static inline void sema_init (struct semaphore *sem, int val)
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{
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*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
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}
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static inline void init_MUTEX (struct semaphore *sem)
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{
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sema_init(sem, 1);
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}
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static inline void init_MUTEX_LOCKED (struct semaphore *sem)
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{
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sema_init(sem, 0);
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}
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asmlinkage void __down_failed(void /* special register calling convention */);
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asmlinkage int __down_failed_interruptible(void /* params in registers */);
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asmlinkage int __down_failed_trylock(void /* params in registers */);
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asmlinkage void __up_wakeup(void /* special register calling convention */);
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asmlinkage void __down(struct semaphore * sem);
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asmlinkage int __down_interruptible(struct semaphore * sem);
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asmlinkage int __down_trylock(struct semaphore * sem);
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asmlinkage void __up(struct semaphore * sem);
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extern spinlock_t semaphore_wake_lock;
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/*
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* This is ugly, but we want the default case to fall through.
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* "down_failed" is a special asm handler that calls the C
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* routine that actually waits. See arch/m68k/lib/semaphore.S
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*/
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static inline void down(struct semaphore * sem)
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{
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might_sleep();
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__asm__ __volatile__(
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"| atomic down operation\n\t"
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"movel %0, %%a1\n\t"
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"lea %%pc@(1f), %%a0\n\t"
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"subql #1, %%a1@\n\t"
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"jmi __down_failed\n"
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"1:"
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: /* no outputs */
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: "g" (sem)
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: "cc", "%a0", "%a1", "memory");
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}
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static inline int down_interruptible(struct semaphore * sem)
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{
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int ret;
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might_sleep();
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__asm__ __volatile__(
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"| atomic down operation\n\t"
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"movel %1, %%a1\n\t"
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"lea %%pc@(1f), %%a0\n\t"
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"subql #1, %%a1@\n\t"
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"jmi __down_failed_interruptible\n\t"
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"clrl %%d0\n"
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"1: movel %%d0, %0\n"
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: "=d" (ret)
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: "g" (sem)
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: "cc", "%d0", "%a0", "%a1", "memory");
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return(ret);
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}
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static inline int down_trylock(struct semaphore * sem)
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{
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register struct semaphore *sem1 __asm__ ("%a1") = sem;
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register int result __asm__ ("%d0");
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__asm__ __volatile__(
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"| atomic down trylock operation\n\t"
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"subql #1,%1@\n\t"
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"jmi 2f\n\t"
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"clrl %0\n"
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"1:\n"
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".section .text.lock,\"ax\"\n"
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".even\n"
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"2:\tpea 1b\n\t"
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"jbra __down_failed_trylock\n"
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".previous"
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: "=d" (result)
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: "a" (sem1)
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: "memory");
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return result;
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}
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/*
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* Note! This is subtle. We jump to wake people up only if
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* the semaphore was negative (== somebody was waiting on it).
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* The default case (no contention) will result in NO
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* jumps for both down() and up().
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*/
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static inline void up(struct semaphore * sem)
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{
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__asm__ __volatile__(
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"| atomic up operation\n\t"
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"movel %0, %%a1\n\t"
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"lea %%pc@(1f), %%a0\n\t"
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"addql #1, %%a1@\n\t"
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"jle __up_wakeup\n"
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"1:"
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: /* no outputs */
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: "g" (sem)
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: "cc", "%a0", "%a1", "memory");
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}
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#endif /* __ASSEMBLY__ */
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#endif
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