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Diffstat (limited to 'include/asm-s390/rwsem.h')
| -rw-r--r-- | include/asm-s390/rwsem.h | 387 |
1 files changed, 0 insertions, 387 deletions
diff --git a/include/asm-s390/rwsem.h b/include/asm-s390/rwsem.h deleted file mode 100644 index 9d2a1797..0000000 --- a/include/asm-s390/rwsem.h +++ /dev/null @@ -1,387 +0,0 @@ -#ifndef _S390_RWSEM_H -#define _S390_RWSEM_H - -/* - * include/asm-s390/rwsem.h - * - * S390 version - * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH, IBM Corporation - * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com) - * - * Based on asm-alpha/semaphore.h and asm-i386/rwsem.h - */ - -/* - * - * The MSW of the count is the negated number of active writers and waiting - * lockers, and the LSW is the total number of active locks - * - * The lock count is initialized to 0 (no active and no waiting lockers). - * - * When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an - * uncontended lock. This can be determined because XADD returns the old value. - * Readers increment by 1 and see a positive value when uncontended, negative - * if there are writers (and maybe) readers waiting (in which case it goes to - * sleep). - * - * The value of WAITING_BIAS supports up to 32766 waiting processes. This can - * be extended to 65534 by manually checking the whole MSW rather than relying - * on the S flag. - * - * The value of ACTIVE_BIAS supports up to 65535 active processes. - * - * This should be totally fair - if anything is waiting, a process that wants a - * lock will go to the back of the queue. When the currently active lock is - * released, if there's a writer at the front of the queue, then that and only - * that will be woken up; if there's a bunch of consequtive readers at the - * front, then they'll all be woken up, but no other readers will be. - */ - -#ifndef _LINUX_RWSEM_H -#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead" -#endif - -#ifdef __KERNEL__ - -#include <linux/list.h> -#include <linux/spinlock.h> - -struct rwsem_waiter; - -extern struct rw_semaphore *rwsem_down_read_failed(struct rw_semaphore *); -extern struct rw_semaphore *rwsem_down_write_failed(struct rw_semaphore *); -extern struct rw_semaphore *rwsem_wake(struct rw_semaphore *); -extern struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *); -extern struct rw_semaphore *rwsem_downgrade_write(struct rw_semaphore *); - -/* - * the semaphore definition - */ -struct rw_semaphore { - signed long count; - spinlock_t wait_lock; - struct list_head wait_list; -#ifdef CONFIG_DEBUG_LOCK_ALLOC - struct lockdep_map dep_map; -#endif -}; - -#ifndef __s390x__ -#define RWSEM_UNLOCKED_VALUE 0x00000000 -#define RWSEM_ACTIVE_BIAS 0x00000001 -#define RWSEM_ACTIVE_MASK 0x0000ffff -#define RWSEM_WAITING_BIAS (-0x00010000) -#else /* __s390x__ */ -#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L -#define RWSEM_ACTIVE_BIAS 0x0000000000000001L -#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL -#define RWSEM_WAITING_BIAS (-0x0000000100000000L) -#endif /* __s390x__ */ -#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS -#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS) - -/* - * initialisation - */ - -#ifdef CONFIG_DEBUG_LOCK_ALLOC -# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname } -#else -# define __RWSEM_DEP_MAP_INIT(lockname) -#endif - -#define __RWSEM_INITIALIZER(name) \ - { RWSEM_UNLOCKED_VALUE, __SPIN_LOCK_UNLOCKED((name).wait.lock), \ - LIST_HEAD_INIT((name).wait_list) __RWSEM_DEP_MAP_INIT(name) } - -#define DECLARE_RWSEM(name) \ - struct rw_semaphore name = __RWSEM_INITIALIZER(name) - -static inline void init_rwsem(struct rw_semaphore *sem) -{ - sem->count = RWSEM_UNLOCKED_VALUE; - spin_lock_init(&sem->wait_lock); - INIT_LIST_HEAD(&sem->wait_list); -} - -extern void __init_rwsem(struct rw_semaphore *sem, const char *name, - struct lock_class_key *key); - -#define init_rwsem(sem) \ -do { \ - static struct lock_class_key __key; \ - \ - __init_rwsem((sem), #sem, &__key); \ -} while (0) - - -/* - * lock for reading - */ -static inline void __down_read(struct rw_semaphore *sem) -{ - signed long old, new; - - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " ahi %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " aghi %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), - "i" (RWSEM_ACTIVE_READ_BIAS) : "cc", "memory"); - if (old < 0) - rwsem_down_read_failed(sem); -} - -/* - * trylock for reading -- returns 1 if successful, 0 if contention - */ -static inline int __down_read_trylock(struct rw_semaphore *sem) -{ - signed long old, new; - - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: ltr %1,%0\n" - " jm 1f\n" - " ahi %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b\n" - "1:" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: ltgr %1,%0\n" - " jm 1f\n" - " aghi %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b\n" - "1:" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), - "i" (RWSEM_ACTIVE_READ_BIAS) : "cc", "memory"); - return old >= 0 ? 1 : 0; -} - -/* - * lock for writing - */ -static inline void __down_write_nested(struct rw_semaphore *sem, int subclass) -{ - signed long old, new, tmp; - - tmp = RWSEM_ACTIVE_WRITE_BIAS; - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " a %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " ag %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), "m" (tmp) - : "cc", "memory"); - if (old != 0) - rwsem_down_write_failed(sem); -} - -static inline void __down_write(struct rw_semaphore *sem) -{ - __down_write_nested(sem, 0); -} - -/* - * trylock for writing -- returns 1 if successful, 0 if contention - */ -static inline int __down_write_trylock(struct rw_semaphore *sem) -{ - signed long old; - - asm volatile( -#ifndef __s390x__ - " l %0,0(%2)\n" - "0: ltr %0,%0\n" - " jnz 1f\n" - " cs %0,%4,0(%2)\n" - " jl 0b\n" -#else /* __s390x__ */ - " lg %0,0(%2)\n" - "0: ltgr %0,%0\n" - " jnz 1f\n" - " csg %0,%4,0(%2)\n" - " jl 0b\n" -#endif /* __s390x__ */ - "1:" - : "=&d" (old), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), - "d" (RWSEM_ACTIVE_WRITE_BIAS) : "cc", "memory"); - return (old == RWSEM_UNLOCKED_VALUE) ? 1 : 0; -} - -/* - * unlock after reading - */ -static inline void __up_read(struct rw_semaphore *sem) -{ - signed long old, new; - - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " ahi %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " aghi %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), - "i" (-RWSEM_ACTIVE_READ_BIAS) - : "cc", "memory"); - if (new < 0) - if ((new & RWSEM_ACTIVE_MASK) == 0) - rwsem_wake(sem); -} - -/* - * unlock after writing - */ -static inline void __up_write(struct rw_semaphore *sem) -{ - signed long old, new, tmp; - - tmp = -RWSEM_ACTIVE_WRITE_BIAS; - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " a %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " ag %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), "m" (tmp) - : "cc", "memory"); - if (new < 0) - if ((new & RWSEM_ACTIVE_MASK) == 0) - rwsem_wake(sem); -} - -/* - * downgrade write lock to read lock - */ -static inline void __downgrade_write(struct rw_semaphore *sem) -{ - signed long old, new, tmp; - - tmp = -RWSEM_WAITING_BIAS; - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " a %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " ag %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), "m" (tmp) - : "cc", "memory"); - if (new > 1) - rwsem_downgrade_wake(sem); -} - -/* - * implement atomic add functionality - */ -static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem) -{ - signed long old, new; - - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " ar %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " agr %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), "d" (delta) - : "cc", "memory"); -} - -/* - * implement exchange and add functionality - */ -static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem) -{ - signed long old, new; - - asm volatile( -#ifndef __s390x__ - " l %0,0(%3)\n" - "0: lr %1,%0\n" - " ar %1,%5\n" - " cs %0,%1,0(%3)\n" - " jl 0b" -#else /* __s390x__ */ - " lg %0,0(%3)\n" - "0: lgr %1,%0\n" - " agr %1,%5\n" - " csg %0,%1,0(%3)\n" - " jl 0b" -#endif /* __s390x__ */ - : "=&d" (old), "=&d" (new), "=m" (sem->count) - : "a" (&sem->count), "m" (sem->count), "d" (delta) - : "cc", "memory"); - return new; -} - -static inline int rwsem_is_locked(struct rw_semaphore *sem) -{ - return (sem->count != 0); -} - -#endif /* __KERNEL__ */ -#endif /* _S390_RWSEM_H */ |
