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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-m68knommu/semaphore.h | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-m68knommu/semaphore.h')
-rw-r--r-- | include/asm-m68knommu/semaphore.h | 157 |
1 files changed, 157 insertions, 0 deletions
diff --git a/include/asm-m68knommu/semaphore.h b/include/asm-m68knommu/semaphore.h new file mode 100644 index 0000000..febe85a --- /dev/null +++ b/include/asm-m68knommu/semaphore.h @@ -0,0 +1,157 @@ +#ifndef _M68K_SEMAPHORE_H +#define _M68K_SEMAPHORE_H + +#define RW_LOCK_BIAS 0x01000000 + +#ifndef __ASSEMBLY__ + +#include <linux/linkage.h> +#include <linux/wait.h> +#include <linux/spinlock.h> +#include <linux/rwsem.h> + +#include <asm/system.h> +#include <asm/atomic.h> + +/* + * Interrupt-safe semaphores.. + * + * (C) Copyright 1996 Linus Torvalds + * + * m68k version by Andreas Schwab + */ + + +struct semaphore { + atomic_t count; + atomic_t waking; + wait_queue_head_t wait; +}; + +#define __SEMAPHORE_INITIALIZER(name, n) \ +{ \ + .count = ATOMIC_INIT(n), \ + .waking = ATOMIC_INIT(0), \ + .wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ +} + +#define __MUTEX_INITIALIZER(name) \ + __SEMAPHORE_INITIALIZER(name,1) + +#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) + +extern inline void sema_init (struct semaphore *sem, int val) +{ + *sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val); +} + +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); +} + +asmlinkage void __down_failed(void /* special register calling convention */); +asmlinkage int __down_failed_interruptible(void /* params in registers */); +asmlinkage int __down_failed_trylock(void /* params in registers */); +asmlinkage void __up_wakeup(void /* special register calling convention */); + +asmlinkage void __down(struct semaphore * sem); +asmlinkage int __down_interruptible(struct semaphore * sem); +asmlinkage int __down_trylock(struct semaphore * sem); +asmlinkage void __up(struct semaphore * sem); + +extern spinlock_t semaphore_wake_lock; + +/* + * 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/m68k/lib/semaphore.S + */ +extern inline void down(struct semaphore * sem) +{ + might_sleep(); + __asm__ __volatile__( + "| atomic down operation\n\t" + "movel %0, %%a1\n\t" + "lea %%pc@(1f), %%a0\n\t" + "subql #1, %%a1@\n\t" + "jmi __down_failed\n" + "1:" + : /* no outputs */ + : "g" (sem) + : "cc", "%a0", "%a1", "memory"); +} + +extern inline int down_interruptible(struct semaphore * sem) +{ + int ret; + + might_sleep(); + __asm__ __volatile__( + "| atomic down operation\n\t" + "movel %1, %%a1\n\t" + "lea %%pc@(1f), %%a0\n\t" + "subql #1, %%a1@\n\t" + "jmi __down_failed_interruptible\n\t" + "clrl %%d0\n" + "1: movel %%d0, %0\n" + : "=d" (ret) + : "g" (sem) + : "cc", "%d0", "%a0", "%a1", "memory"); + return(ret); +} + +extern inline int down_trylock(struct semaphore * sem) +{ + register struct semaphore *sem1 __asm__ ("%a1") = sem; + register int result __asm__ ("%d0"); + + __asm__ __volatile__( + "| atomic down trylock operation\n\t" + "subql #1,%1@\n\t" + "jmi 2f\n\t" + "clrl %0\n" + "1:\n" + ".section .text.lock,\"ax\"\n" + ".even\n" + "2:\tpea 1b\n\t" + "jbra __down_failed_trylock\n" + ".previous" + : "=d" (result) + : "a" (sem1) + : "memory"); + return result; +} + +/* + * Note! This is subtle. We jump to wake people up only if + * the semaphore was negative (== somebody was waiting on it). + * The default case (no contention) will result in NO + * jumps for both down() and up(). + */ +extern inline void up(struct semaphore * sem) +{ + __asm__ __volatile__( + "| atomic up operation\n\t" + "movel %0, %%a1\n\t" + "lea %%pc@(1f), %%a0\n\t" + "addql #1, %%a1@\n\t" + "jle __up_wakeup\n" + "1:" + : /* no outputs */ + : "g" (sem) + : "cc", "%a0", "%a1", "memory"); +} + +#endif /* __ASSEMBLY__ */ + +#endif |