diff options
author | Ralf Baechle <ralf@linux-mips.org> | 2001-01-10 05:27:25 +0000 |
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committer | Ralf Baechle <ralf@linux-mips.org> | 2001-01-10 05:27:25 +0000 |
commit | c9c06167e7933d93a6e396174c68abf242294abb (patch) | |
tree | d9a8bb30663e9a3405a1ef37ffb62bc14b9f019f /include/asm-parisc/semaphore.h | |
parent | f79e8cc3c34e4192a3e5ef4cc9c6542fdef703c0 (diff) |
Merge with Linux 2.4.0-test12.
Diffstat (limited to 'include/asm-parisc/semaphore.h')
-rw-r--r-- | include/asm-parisc/semaphore.h | 301 |
1 files changed, 301 insertions, 0 deletions
diff --git a/include/asm-parisc/semaphore.h b/include/asm-parisc/semaphore.h new file mode 100644 index 000000000..12deca83c --- /dev/null +++ b/include/asm-parisc/semaphore.h @@ -0,0 +1,301 @@ +#ifndef _ASM_PARISC_SEMAPHORE_H +#define _ASM_PARISC_SEMAPHORE_H + +#include <linux/linkage.h> + +/* + * SMP- and interrupt-safe semaphores. + * + * (C) Copyright 1996 Linus Torvalds + * + * SuperH verison by Niibe Yutaka + * + */ + +/* if you're going to use out-of-line slowpaths, use .section .lock.text, + * not .text.lock or the -ffunction-sections monster will eat you alive + */ + +#include <linux/spinlock.h> + +#include <asm/system.h> +#include <asm/atomic.h> + +struct semaphore { + atomic_t count; + int waking; + wait_queue_head_t wait; +#if WAITQUEUE_DEBUG + long __magic; +#endif +}; + +#if WAITQUEUE_DEBUG +# define __SEM_DEBUG_INIT(name) \ + , (long)&(name).__magic +#else +# define __SEM_DEBUG_INIT(name) +#endif + +#define __SEMAPHORE_INITIALIZER(name,count) \ +{ ATOMIC_INIT(count), 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ + __SEM_DEBUG_INIT(name) } + +#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); + * + * i'd rather use the more flexible initialization above, but sadly + * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well. + */ + atomic_set(&sem->count, val); + sem->waking = 0; + init_waitqueue_head(&sem->wait); +#if WAITQUEUE_DEBUG + sem->__magic = (long)&sem->__magic; +#endif +} + +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; + +extern __inline__ void down(struct semaphore * sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + if (atomic_dec_return(&sem->count) < 0) + __down(sem); +} + +extern __inline__ int down_interruptible(struct semaphore * sem) +{ + int ret = 0; +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + if (atomic_dec_return(&sem->count) < 0) + ret = __down_interruptible(sem); + return ret; +} + +extern __inline__ int down_trylock(struct semaphore * sem) +{ + int ret = 0; +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + + if (atomic_dec_return(&sem->count) < 0) + ret = __down_trylock(sem); + return ret; +} + +/* + * Note! This is subtle. We jump to wake people up only if + * the semaphore was negative (== somebody was waiting on it). + */ +extern __inline__ void up(struct semaphore * sem) +{ +#if WAITQUEUE_DEBUG + CHECK_MAGIC(sem->__magic); +#endif + if (atomic_inc_return(&sem->count) <= 0) + __up(sem); +} + +/* rw mutexes (should that be mutices? =) -- throw rw + * spinlocks and semaphores together, and this is what we + * end up with... + * + * The lock is initialized to BIAS. This way, a writer + * subtracts BIAS ands gets 0 for the case of an uncontended + * lock. Readers decrement by 1 and see a positive value + * when uncontended, negative if there are writers waiting + * (in which case it goes to sleep). + * + * The value 0x01000000 supports up to 128 processors and + * lots of processes. BIAS must be chosen such that subl'ing + * BIAS once per CPU will result in the long remaining + * negative. + * + * In terms of fairness, this should result in the lock + * flopping back and forth between readers and writers + * under heavy use. + * + * -ben + */ +struct rw_semaphore { + atomic_t count; + volatile unsigned char write_bias_granted; + volatile unsigned char read_bias_granted; + volatile unsigned char pad1; + volatile unsigned char pad2; + wait_queue_head_t wait; + wait_queue_head_t write_bias_wait; +#if WAITQUEUE_DEBUG + long __magic; + atomic_t readers; + atomic_t writers; +#endif +}; + +#if WAITQUEUE_DEBUG +#define __RWSEM_DEBUG_INIT , ATOMIC_INIT(0), ATOMIC_INIT(0) +#else +#define __RWSEM_DEBUG_INIT /* */ +#endif + +#define RW_LOCK_BIAS 0x01000000 + +#define __RWSEM_INITIALIZER(name,count) \ +{ ATOMIC_INIT(count), 0, 0, 0, 0, __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \ + __WAIT_QUEUE_HEAD_INITIALIZER((name).write_bias_wait) \ + __SEM_DEBUG_INIT(name) __RWSEM_DEBUG_INIT } + +#define __DECLARE_RWSEM_GENERIC(name,count) \ + struct rw_semaphore name = __RWSEM_INITIALIZER(name,count) + +#define DECLARE_RWSEM(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS) +#define DECLARE_RWSEM_READ_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,RW_LOCK_BIAS-1) +#define DECLARE_RWSEM_WRITE_LOCKED(name) __DECLARE_RWSEM_GENERIC(name,0) + +extern inline void init_rwsem(struct rw_semaphore *sem) +{ + atomic_set(&sem->count, RW_LOCK_BIAS); + sem->read_bias_granted = 0; + sem->write_bias_granted = 0; + init_waitqueue_head(&sem->wait); + init_waitqueue_head(&sem->write_bias_wait); +#if WAITQUEUE_DEBUG + sem->__magic = (long)&sem->__magic; + atomic_set(&sem->readers, 0); + atomic_set(&sem->writers, 0); +#endif +} + +#ifdef FIXME_WILLY_FIXME_FOR_REAL_THIS_TIME +extern struct rw_semaphore *__build_read_lock(struct rw_semaphore *sem, const char *what); +extern struct rw_semaphore *__build_write_lock(struct rw_semaphore *sem, const char *what); +#endif + +/* we use FASTCALL convention for the helpers */ +extern struct rw_semaphore *FASTCALL(__down_read_failed(struct rw_semaphore *sem)); +extern struct rw_semaphore *FASTCALL(__down_write_failed(struct rw_semaphore *sem)); +extern struct rw_semaphore *FASTCALL(__rwsem_wake(struct rw_semaphore *sem)); + +extern inline void down_read(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + if (sem->__magic != (long)&sem->__magic) + BUG(); +#endif +#ifdef FIXME_WILLY_FIXME_FOR_REAL_THIS_TIME + __build_read_lock(sem, "__down_read_failed"); +#endif +#if WAITQUEUE_DEBUG + if (sem->write_bias_granted) + BUG(); + if (atomic_read(&sem->writers)) + BUG(); + atomic_inc(&sem->readers); +#endif +} + +extern inline void down_write(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + if (sem->__magic != (long)&sem->__magic) + BUG(); +#endif +#ifdef FIXME_WILLY_FIXME_FOR_REAL_THIS_TIME + __build_write_lock(sem, "__down_write_failed"); +#endif +#if WAITQUEUE_DEBUG + if (atomic_read(&sem->writers)) + BUG(); + if (atomic_read(&sem->readers)) + BUG(); + if (sem->read_bias_granted) + BUG(); + if (sem->write_bias_granted) + BUG(); + atomic_inc(&sem->writers); +#endif +} + +/* When a reader does a release, the only significant + * case is when there was a writer waiting, and we've + * bumped the count to 0: we must wake the writer up. + */ +extern inline void __up_read(struct rw_semaphore *sem) +{ +} + +/* releasing the writer is easy -- just release it and + * wake up any sleepers. + */ +extern inline void __up_write(struct rw_semaphore *sem) +{ +} + +extern inline void up_read(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + if (sem->write_bias_granted) + BUG(); + if (atomic_read(&sem->writers)) + BUG(); + atomic_dec(&sem->readers); +#endif + __up_read(sem); +} + +extern inline void up_write(struct rw_semaphore *sem) +{ +#if WAITQUEUE_DEBUG + if (sem->read_bias_granted) + BUG(); + if (sem->write_bias_granted) + BUG(); + if (atomic_read(&sem->readers)) + BUG(); + if (atomic_read(&sem->writers) != 1) + BUG(); + atomic_dec(&sem->writers); +#endif + __up_write(sem); +} + +#endif /* _ASM_PARISC_SEMAPHORE_H */ |