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