diff options
author | Matthew Wilcox <matthew@wil.cx> | 2008-03-08 05:55:58 +0300 |
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committer | Matthew Wilcox <willy@linux.intel.com> | 2008-04-17 18:42:34 +0400 |
commit | 64ac24e738823161693bf791f87adc802cf529ff (patch) | |
tree | 19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-h8300/semaphore.h | |
parent | e48b3deee475134585eed03e7afebe4bf9e0dba9 (diff) | |
download | linux-64ac24e738823161693bf791f87adc802cf529ff.tar.xz |
Generic semaphore implementation
Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility. Thanks to Peter Zijlstra for fixing the lockdep
warning. Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-h8300/semaphore.h')
-rw-r--r-- | include/asm-h8300/semaphore.h | 191 |
1 files changed, 1 insertions, 190 deletions
diff --git a/include/asm-h8300/semaphore.h b/include/asm-h8300/semaphore.h index f3ffff83ff09..d9b2034ed1d2 100644 --- a/include/asm-h8300/semaphore.h +++ b/include/asm-h8300/semaphore.h @@ -1,190 +1 @@ -#ifndef _H8300_SEMAPHORE_H -#define _H8300_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 - * - * H8/300 version by Yoshinori Sato - */ - - -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) - -static 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 - */ -static inline void down(struct semaphore * sem) -{ - register atomic_t *count asm("er0"); - - might_sleep(); - - count = &(sem->count); - __asm__ __volatile__( - "stc ccr,r3l\n\t" - "orc #0x80,ccr\n\t" - "mov.l %2, er1\n\t" - "dec.l #1,er1\n\t" - "mov.l er1,%0\n\t" - "bpl 1f\n\t" - "ldc r3l,ccr\n\t" - "mov.l %1,er0\n\t" - "jsr @___down\n\t" - "bra 2f\n" - "1:\n\t" - "ldc r3l,ccr\n" - "2:" - : "=m"(*count) - : "g"(sem),"m"(*count) - : "cc", "er1", "er2", "er3"); -} - -static inline int down_interruptible(struct semaphore * sem) -{ - register atomic_t *count asm("er0"); - - might_sleep(); - - count = &(sem->count); - __asm__ __volatile__( - "stc ccr,r1l\n\t" - "orc #0x80,ccr\n\t" - "mov.l %3, er2\n\t" - "dec.l #1,er2\n\t" - "mov.l er2,%1\n\t" - "bpl 1f\n\t" - "ldc r1l,ccr\n\t" - "mov.l %2,er0\n\t" - "jsr @___down_interruptible\n\t" - "bra 2f\n" - "1:\n\t" - "ldc r1l,ccr\n\t" - "sub.l %0,%0\n\t" - "2:\n\t" - : "=r" (count),"=m" (*count) - : "g"(sem),"m"(*count) - : "cc", "er1", "er2", "er3"); - return (int)count; -} - -static inline int down_trylock(struct semaphore * sem) -{ - register atomic_t *count asm("er0"); - - count = &(sem->count); - __asm__ __volatile__( - "stc ccr,r3l\n\t" - "orc #0x80,ccr\n\t" - "mov.l %3,er2\n\t" - "dec.l #1,er2\n\t" - "mov.l er2,%0\n\t" - "bpl 1f\n\t" - "ldc r3l,ccr\n\t" - "jmp @3f\n\t" - LOCK_SECTION_START(".align 2\n\t") - "3:\n\t" - "mov.l %2,er0\n\t" - "jsr @___down_trylock\n\t" - "jmp @2f\n\t" - LOCK_SECTION_END - "1:\n\t" - "ldc r3l,ccr\n\t" - "sub.l %1,%1\n" - "2:" - : "=m" (*count),"=r"(count) - : "g"(sem),"m"(*count) - : "cc", "er1","er2", "er3"); - return (int)count; -} - -/* - * 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(). - */ -static inline void up(struct semaphore * sem) -{ - register atomic_t *count asm("er0"); - - count = &(sem->count); - __asm__ __volatile__( - "stc ccr,r3l\n\t" - "orc #0x80,ccr\n\t" - "mov.l %2,er1\n\t" - "inc.l #1,er1\n\t" - "mov.l er1,%0\n\t" - "ldc r3l,ccr\n\t" - "sub.l er2,er2\n\t" - "cmp.l er2,er1\n\t" - "bgt 1f\n\t" - "mov.l %1,er0\n\t" - "jsr @___up\n" - "1:" - : "=m"(*count) - : "g"(sem),"m"(*count) - : "cc", "er1", "er2", "er3"); -} - -#endif /* __ASSEMBLY__ */ - -#endif +#include <linux/semaphore.h> |