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#ifndef _I386_SEMAPHORE_H
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#define _I386_SEMAPHORE_H
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#include <linux/linkage.h>
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#ifdef __KERNEL__
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/*
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 * SMP- and interrupt-safe semaphores..
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 *
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 * (C) Copyright 1996 Linus Torvalds
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 *
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 * Modified 1996-12-23 by Dave Grothe <dave@gcom.com> to fix bugs in
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 *                     the original code and to make semaphore waits
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 *                     interruptible so that processes waiting on
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 *                     semaphores can be killed.
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 * Modified 1999-02-14 by Andrea Arcangeli, split the sched.c helper
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 *                     functions in asm/sempahore-helper.h while fixing a
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 *                     potential and subtle race discovered by Ulrich Schmid
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 *                     in down_interruptible(). Since I started to play here I
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 *                     also implemented the `trylock' semaphore operation.
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 *          1999-07-02 Artur Skawina <skawina@geocities.com>
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 *                     Optimized "0(ecx)" -> "(ecx)" (the assembler does not
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 *                     do this). Changed calling sequences from push/jmp to
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 *                     traditional call/ret.
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 * Modified 2001-01-01 Andreas Franck <afranck@gmx.de>
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 *                     Some hacks to ensure compatibility with recent
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 *                     GCC snapshots, to avoid stack corruption when compiling
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 *                     with -fomit-frame-pointer. It's not sure if this will
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 *                     be fixed in GCC, as our previous implementation was a
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 *                     bit dubious.
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 *
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 * If you would like to see an analysis of this implementation, please
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 * ftp to gcom.com and download the file
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 * /pub/linux/src/semaphore/semaphore-2.0.24.tar.gz.
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 *
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 */
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <linux/wait.h>
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#include <linux/rwsem.h>
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struct semaphore {
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        atomic_t count;
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        int sleepers;
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        wait_queue_head_t wait;
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#ifdef WAITQUEUE_DEBUG
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        long __magic;
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#endif
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};
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#ifdef WAITQUEUE_DEBUG
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# define __SEM_DEBUG_INIT(name) \
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                , (int)&(name).__magic
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#else
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# define __SEM_DEBUG_INIT(name)
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#endif
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#define __SEMAPHORE_INITIALIZER(name,count) \
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{ ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \
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        __SEM_DEBUG_INIT(name) }
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#define __MUTEX_INITIALIZER(name) \
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        __SEMAPHORE_INITIALIZER(name,1)
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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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#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
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static inline void sema_init (struct semaphore *sem, int val)
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{
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/*
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 *      *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
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 *
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 * i'd rather use the more flexible initialization above, but sadly
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 * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
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 */
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        atomic_set(&sem->count, val);
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        sem->sleepers = 0;
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        init_waitqueue_head(&sem->wait);
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#ifdef WAITQUEUE_DEBUG
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        sem->__magic = (int)&sem->__magic;
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#endif
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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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/*
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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/i386/kernel/semaphore.c
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 */
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static inline void down(struct semaphore * sem)
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{
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#ifdef WAITQUEUE_DEBUG
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        CHECK_MAGIC(sem->__magic);
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#endif
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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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                LOCK "decl %0\n\t"     /* --sem->count */
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                "js 2f\n"
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                "1:\n"
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                LOCK_SECTION_START("")
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                "2:\tcall __down_failed\n\t"
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                "jmp 1b\n"
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                LOCK_SECTION_END
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                :"=m" (sem->count)
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                :"c" (sem)
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                :"memory");
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}
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/*
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 * Interruptible try to acquire a semaphore.  If we obtained
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 * it, return zero.  If we were interrupted, returns -EINTR
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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 result;
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#ifdef WAITQUEUE_DEBUG
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        CHECK_MAGIC(sem->__magic);
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#endif
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        might_sleep();
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        __asm__ __volatile__(
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                "# atomic interruptible down operation\n\t"
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                LOCK "decl %1\n\t"     /* --sem->count */
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                "js 2f\n\t"
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                "xorl %0,%0\n"
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                "1:\n"
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                LOCK_SECTION_START("")
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                "2:\tcall __down_failed_interruptible\n\t"
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                "jmp 1b\n"
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                LOCK_SECTION_END
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                :"=a" (result), "=m" (sem->count)
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                :"c" (sem)
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                :"memory");
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        return result;
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}
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/*
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 * Non-blockingly attempt to down() a semaphore.
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 * Returns zero if we acquired it
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 */
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static inline int down_trylock(struct semaphore * sem)
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{
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        int result;
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#ifdef WAITQUEUE_DEBUG
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        CHECK_MAGIC(sem->__magic);
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#endif
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        __asm__ __volatile__(
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                "# atomic interruptible down operation\n\t"
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                LOCK "decl %1\n\t"     /* --sem->count */
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                "js 2f\n\t"
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                "xorl %0,%0\n"
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                "1:\n"
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                LOCK_SECTION_START("")
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                "2:\tcall __down_failed_trylock\n\t"
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                "jmp 1b\n"
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                LOCK_SECTION_END
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                :"=a" (result), "=m" (sem->count)
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                :"c" (sem)
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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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#ifdef WAITQUEUE_DEBUG
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        CHECK_MAGIC(sem->__magic);
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#endif
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        __asm__ __volatile__(
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                "# atomic up operation\n\t"
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                LOCK "incl %0\n\t"     /* ++sem->count */
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                "jle 2f\n"
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                "1:\n"
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                LOCK_SECTION_START("")
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                "2:\tcall __up_wakeup\n\t"
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                "jmp 1b\n"
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                LOCK_SECTION_END
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                ".subsection 0\n"
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                :"=m" (sem->count)
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                :"c" (sem)
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                :"memory");
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}
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#endif
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#endif