From 64ac24e738823161693bf791f87adc802cf529ff Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 7 Mar 2008 21:55:58 -0500 Subject: 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 Acked-by: Ingo Molnar --- include/asm-h8300/semaphore-helper.h | 85 ---------------- include/asm-h8300/semaphore.h | 191 +---------------------------------- 2 files changed, 1 insertion(+), 275 deletions(-) delete mode 100644 include/asm-h8300/semaphore-helper.h (limited to 'include/asm-h8300') diff --git a/include/asm-h8300/semaphore-helper.h b/include/asm-h8300/semaphore-helper.h deleted file mode 100644 index 4fea36be5fd..00000000000 --- a/include/asm-h8300/semaphore-helper.h +++ /dev/null @@ -1,85 +0,0 @@ -#ifndef _H8300_SEMAPHORE_HELPER_H -#define _H8300_SEMAPHORE_HELPER_H - -/* - * SMP- and interrupt-safe semaphores helper functions. - * - * (C) Copyright 1996 Linus Torvalds - * - * based on - * m68k version by Andreas Schwab - */ - -#include - -/* - * These two _must_ execute atomically wrt each other. - */ -static inline void wake_one_more(struct semaphore * sem) -{ - atomic_inc((atomic_t *)&sem->sleepers); -} - -static inline int waking_non_zero(struct semaphore *sem) -{ - int ret; - unsigned long flags; - - spin_lock_irqsave(&semaphore_wake_lock, flags); - ret = 0; - if (sem->sleepers > 0) { - sem->sleepers--; - ret = 1; - } - spin_unlock_irqrestore(&semaphore_wake_lock, flags); - return ret; -} - -/* - * waking_non_zero_interruptible: - * 1 got the lock - * 0 go to sleep - * -EINTR interrupted - */ -static inline int waking_non_zero_interruptible(struct semaphore *sem, - struct task_struct *tsk) -{ - int ret; - unsigned long flags; - - spin_lock_irqsave(&semaphore_wake_lock, flags); - ret = 0; - if (sem->sleepers > 0) { - sem->sleepers--; - ret = 1; - } else if (signal_pending(tsk)) { - atomic_inc(&sem->count); - ret = -EINTR; - } - spin_unlock_irqrestore(&semaphore_wake_lock, flags); - return ret; -} - -/* - * waking_non_zero_trylock: - * 1 failed to lock - * 0 got the lock - */ -static inline int waking_non_zero_trylock(struct semaphore *sem) -{ - int ret; - unsigned long flags; - - spin_lock_irqsave(&semaphore_wake_lock, flags); - ret = 1; - if (sem->sleepers <= 0) - atomic_inc(&sem->count); - else { - sem->sleepers--; - ret = 0; - } - spin_unlock_irqrestore(&semaphore_wake_lock, flags); - return ret; -} - -#endif diff --git a/include/asm-h8300/semaphore.h b/include/asm-h8300/semaphore.h index f3ffff83ff0..d9b2034ed1d 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 -#include -#include -#include - -#include -#include - -/* - * 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 -- cgit v1.2.3