178 lines
4.3 KiB
C
178 lines
4.3 KiB
C
/*
|
|
* include/asm-s390/spinlock.h
|
|
*
|
|
* S390 version
|
|
* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
|
|
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
|
|
*
|
|
* Derived from "include/asm-i386/spinlock.h"
|
|
*/
|
|
|
|
#ifndef __ASM_SPINLOCK_H
|
|
#define __ASM_SPINLOCK_H
|
|
|
|
#include <linux/smp.h>
|
|
|
|
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
|
|
|
|
static inline int
|
|
_raw_compare_and_swap(volatile unsigned int *lock,
|
|
unsigned int old, unsigned int new)
|
|
{
|
|
asm volatile(
|
|
" cs %0,%3,%1"
|
|
: "=d" (old), "=Q" (*lock)
|
|
: "0" (old), "d" (new), "Q" (*lock)
|
|
: "cc", "memory" );
|
|
return old;
|
|
}
|
|
|
|
#else /* __GNUC__ */
|
|
|
|
static inline int
|
|
_raw_compare_and_swap(volatile unsigned int *lock,
|
|
unsigned int old, unsigned int new)
|
|
{
|
|
asm volatile(
|
|
" cs %0,%3,0(%4)"
|
|
: "=d" (old), "=m" (*lock)
|
|
: "0" (old), "d" (new), "a" (lock), "m" (*lock)
|
|
: "cc", "memory" );
|
|
return old;
|
|
}
|
|
|
|
#endif /* __GNUC__ */
|
|
|
|
/*
|
|
* Simple spin lock operations. There are two variants, one clears IRQ's
|
|
* on the local processor, one does not.
|
|
*
|
|
* We make no fairness assumptions. They have a cost.
|
|
*
|
|
* (the type definitions are in asm/spinlock_types.h)
|
|
*/
|
|
|
|
#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)
|
|
#define __raw_spin_unlock_wait(lock) \
|
|
do { while (__raw_spin_is_locked(lock)) \
|
|
_raw_spin_relax(lock); } while (0)
|
|
|
|
extern void _raw_spin_lock_wait(raw_spinlock_t *);
|
|
extern void _raw_spin_lock_wait_flags(raw_spinlock_t *, unsigned long flags);
|
|
extern int _raw_spin_trylock_retry(raw_spinlock_t *);
|
|
extern void _raw_spin_relax(raw_spinlock_t *lock);
|
|
|
|
static inline void __raw_spin_lock(raw_spinlock_t *lp)
|
|
{
|
|
int old;
|
|
|
|
old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
|
|
if (likely(old == 0))
|
|
return;
|
|
_raw_spin_lock_wait(lp);
|
|
}
|
|
|
|
static inline void __raw_spin_lock_flags(raw_spinlock_t *lp,
|
|
unsigned long flags)
|
|
{
|
|
int old;
|
|
|
|
old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
|
|
if (likely(old == 0))
|
|
return;
|
|
_raw_spin_lock_wait_flags(lp, flags);
|
|
}
|
|
|
|
static inline int __raw_spin_trylock(raw_spinlock_t *lp)
|
|
{
|
|
int old;
|
|
|
|
old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
|
|
if (likely(old == 0))
|
|
return 1;
|
|
return _raw_spin_trylock_retry(lp);
|
|
}
|
|
|
|
static inline void __raw_spin_unlock(raw_spinlock_t *lp)
|
|
{
|
|
_raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);
|
|
}
|
|
|
|
/*
|
|
* Read-write spinlocks, allowing multiple readers
|
|
* but only one writer.
|
|
*
|
|
* NOTE! it is quite common to have readers in interrupts
|
|
* but no interrupt writers. For those circumstances we
|
|
* can "mix" irq-safe locks - any writer needs to get a
|
|
* irq-safe write-lock, but readers can get non-irqsafe
|
|
* read-locks.
|
|
*/
|
|
|
|
/**
|
|
* read_can_lock - would read_trylock() succeed?
|
|
* @lock: the rwlock in question.
|
|
*/
|
|
#define __raw_read_can_lock(x) ((int)(x)->lock >= 0)
|
|
|
|
/**
|
|
* write_can_lock - would write_trylock() succeed?
|
|
* @lock: the rwlock in question.
|
|
*/
|
|
#define __raw_write_can_lock(x) ((x)->lock == 0)
|
|
|
|
extern void _raw_read_lock_wait(raw_rwlock_t *lp);
|
|
extern int _raw_read_trylock_retry(raw_rwlock_t *lp);
|
|
extern void _raw_write_lock_wait(raw_rwlock_t *lp);
|
|
extern int _raw_write_trylock_retry(raw_rwlock_t *lp);
|
|
|
|
static inline void __raw_read_lock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned int old;
|
|
old = rw->lock & 0x7fffffffU;
|
|
if (_raw_compare_and_swap(&rw->lock, old, old + 1) != old)
|
|
_raw_read_lock_wait(rw);
|
|
}
|
|
|
|
static inline void __raw_read_unlock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned int old, cmp;
|
|
|
|
old = rw->lock;
|
|
do {
|
|
cmp = old;
|
|
old = _raw_compare_and_swap(&rw->lock, old, old - 1);
|
|
} while (cmp != old);
|
|
}
|
|
|
|
static inline void __raw_write_lock(raw_rwlock_t *rw)
|
|
{
|
|
if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
|
|
_raw_write_lock_wait(rw);
|
|
}
|
|
|
|
static inline void __raw_write_unlock(raw_rwlock_t *rw)
|
|
{
|
|
_raw_compare_and_swap(&rw->lock, 0x80000000, 0);
|
|
}
|
|
|
|
static inline int __raw_read_trylock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned int old;
|
|
old = rw->lock & 0x7fffffffU;
|
|
if (likely(_raw_compare_and_swap(&rw->lock, old, old + 1) == old))
|
|
return 1;
|
|
return _raw_read_trylock_retry(rw);
|
|
}
|
|
|
|
static inline int __raw_write_trylock(raw_rwlock_t *rw)
|
|
{
|
|
if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
|
|
return 1;
|
|
return _raw_write_trylock_retry(rw);
|
|
}
|
|
|
|
#define _raw_read_relax(lock) cpu_relax()
|
|
#define _raw_write_relax(lock) cpu_relax()
|
|
|
|
#endif /* __ASM_SPINLOCK_H */
|