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Diffstat (limited to 'arch/s390/include/asm/spinlock.h')
| -rw-r--r-- | arch/s390/include/asm/spinlock.h | 178 |
1 files changed, 178 insertions, 0 deletions
diff --git a/arch/s390/include/asm/spinlock.h b/arch/s390/include/asm/spinlock.h new file mode 100644 index 00000000000..df84ae96915 --- /dev/null +++ b/arch/s390/include/asm/spinlock.h @@ -0,0 +1,178 @@ +/* + * 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 */ |