[linux.git] / include / asm-s390 / rwsem.h

#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 ([email protected])
 *
 *  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, 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 */
Commit	Line	Data
1da177e4 LT	1	#ifndef _S390_RWSEM_H
	2	#define _S390_RWSEM_H
	3
	4	/*
	5	* include/asm-s390/rwsem.h
	6	*
	7	* S390 version
	8	* Copyright (C) 2002 IBM Deutschland Entwicklung GmbH, IBM Corporation
	9	* Author(s): Martin Schwidefsky ([email protected])
	10	*
	11	* Based on asm-alpha/semaphore.h and asm-i386/rwsem.h
	12	*/
	13
	14	/*
	15	*
	16	* The MSW of the count is the negated number of active writers and waiting
	17	* lockers, and the LSW is the total number of active locks
	18	*
	19	* The lock count is initialized to 0 (no active and no waiting lockers).
	20	*
	21	* When a writer subtracts WRITE_BIAS, it'll get 0xffff0001 for the case of an
	22	* uncontended lock. This can be determined because XADD returns the old value.
	23	* Readers increment by 1 and see a positive value when uncontended, negative
	24	* if there are writers (and maybe) readers waiting (in which case it goes to
	25	* sleep).
	26	*
	27	* The value of WAITING_BIAS supports up to 32766 waiting processes. This can
	28	* be extended to 65534 by manually checking the whole MSW rather than relying
	29	* on the S flag.
	30	*
	31	* The value of ACTIVE_BIAS supports up to 65535 active processes.
	32	*
	33	* This should be totally fair - if anything is waiting, a process that wants a
	34	* lock will go to the back of the queue. When the currently active lock is
	35	* released, if there's a writer at the front of the queue, then that and only
	36	* that will be woken up; if there's a bunch of consequtive readers at the
	37	* front, then they'll all be woken up, but no other readers will be.
	38	*/
	39
	40	#ifndef _LINUX_RWSEM_H
	41	#error "please don't include asm/rwsem.h directly, use linux/rwsem.h instead"
	42	#endif
	43
	44	#ifdef __KERNEL__
	45
	46	#include <linux/list.h>
	47	#include <linux/spinlock.h>
	48
	49	struct rwsem_waiter;
	50
	51	extern struct rw_semaphore rwsem_down_read_failed(struct rw_semaphore );
	52	extern struct rw_semaphore rwsem_down_write_failed(struct rw_semaphore );
	53	extern struct rw_semaphore rwsem_wake(struct rw_semaphore );
	54	extern struct rw_semaphore rwsem_downgrade_wake(struct rw_semaphore );
	55	extern struct rw_semaphore rwsem_downgrade_write(struct rw_semaphore );
	56
	57	/*
	58	* the semaphore definition
	59	*/
	60	struct rw_semaphore {
	61	signed long count;
	62	spinlock_t wait_lock;
	63	struct list_head wait_list;
4ea2176d IM	64	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	65	struct lockdep_map dep_map;
	66	#endif
1da177e4 LT	67	};
	68
	69	#ifndef __s390x__
	70	#define RWSEM_UNLOCKED_VALUE 0x00000000
	71	#define RWSEM_ACTIVE_BIAS 0x00000001
	72	#define RWSEM_ACTIVE_MASK 0x0000ffff
	73	#define RWSEM_WAITING_BIAS (-0x00010000)
	74	#else /* __s390x__ */
	75	#define RWSEM_UNLOCKED_VALUE 0x0000000000000000L
	76	#define RWSEM_ACTIVE_BIAS 0x0000000000000001L
	77	#define RWSEM_ACTIVE_MASK 0x00000000ffffffffL
	78	#define RWSEM_WAITING_BIAS (-0x0000000100000000L)
	79	#endif /* __s390x__ */
	80	#define RWSEM_ACTIVE_READ_BIAS RWSEM_ACTIVE_BIAS
	81	#define RWSEM_ACTIVE_WRITE_BIAS (RWSEM_WAITING_BIAS + RWSEM_ACTIVE_BIAS)
	82
	83	/*
	84	* initialisation
	85	*/
4ea2176d IM	86
	87	#ifdef CONFIG_DEBUG_LOCK_ALLOC
	88	# define __RWSEM_DEP_MAP_INIT(lockname) , .dep_map = { .name = #lockname }
	89	#else
	90	# define __RWSEM_DEP_MAP_INIT(lockname)
	91	#endif
	92
1da177e4	93	#define __RWSEM_INITIALIZER(name) \
4ea2176d IM	94	{ RWSEM_UNLOCKED_VALUE, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) \
4ea2176d IM	95	__RWSEM_DEP_MAP_INIT(name) }
1da177e4 LT	96
	97	#define DECLARE_RWSEM(name) \
	98	struct rw_semaphore name = __RWSEM_INITIALIZER(name)
	99
	100	static inline void init_rwsem(struct rw_semaphore *sem)
	101	{
	102	sem->count = RWSEM_UNLOCKED_VALUE;
	103	spin_lock_init(&sem->wait_lock);
	104	INIT_LIST_HEAD(&sem->wait_list);
	105	}
	106
4ea2176d IM	107	extern void __init_rwsem(struct rw_semaphore sem, const char name,
	108	struct lock_class_key *key);
	109
	110	#define init_rwsem(sem) \
	111	do { \
	112	static struct lock_class_key __key; \
	113	\
	114	__init_rwsem((sem), #sem, &__key); \
	115	} while (0)
	116
	117
1da177e4 LT	118	/*
	119	* lock for reading
	120	*/
	121	static inline void __down_read(struct rw_semaphore *sem)
	122	{
	123	signed long old, new;
	124
94c12cc7	125	asm volatile(
1da177e4	126	#ifndef __s390x__
94c12cc7 MS	127	" l %0,0(%3)\n"
	128	"0: lr %1,%0\n"
	129	" ahi %1,%5\n"
	130	" cs %0,%1,0(%3)\n"
	131	" jl 0b"
1da177e4	132	#else /* __s390x__ */
94c12cc7 MS	133	" lg %0,0(%3)\n"
	134	"0: lgr %1,%0\n"
	135	" aghi %1,%5\n"
	136	" csg %0,%1,0(%3)\n"
	137	" jl 0b"
1da177e4	138	#endif /* __s390x__ */
94c12cc7	139	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	140	: "a" (&sem->count), "m" (sem->count),
94c12cc7	141	"i" (RWSEM_ACTIVE_READ_BIAS) : "cc", "memory");
1da177e4 LT	142	if (old < 0)
	143	rwsem_down_read_failed(sem);
	144	}
	145
	146	/*
	147	* trylock for reading -- returns 1 if successful, 0 if contention
	148	*/
	149	static inline int __down_read_trylock(struct rw_semaphore *sem)
	150	{
	151	signed long old, new;
	152
94c12cc7	153	asm volatile(
1da177e4	154	#ifndef __s390x__
94c12cc7 MS	155	" l %0,0(%3)\n"
	156	"0: ltr %1,%0\n"
	157	" jm 1f\n"
	158	" ahi %1,%5\n"
	159	" cs %0,%1,0(%3)\n"
	160	" jl 0b\n"
1da177e4 LT	161	"1:"
1da177e4 LT	162	#else /* __s390x__ */
94c12cc7 MS	163	" lg %0,0(%3)\n"
	164	"0: ltgr %1,%0\n"
	165	" jm 1f\n"
	166	" aghi %1,%5\n"
	167	" csg %0,%1,0(%3)\n"
	168	" jl 0b\n"
1da177e4 LT	169	"1:"
1da177e4 LT	170	#endif /* __s390x__ */
94c12cc7	171	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	172	: "a" (&sem->count), "m" (sem->count),
94c12cc7	173	"i" (RWSEM_ACTIVE_READ_BIAS) : "cc", "memory");
1da177e4 LT	174	return old >= 0 ? 1 : 0;
	175	}
	176
	177	/*
	178	* lock for writing
	179	*/
4ea2176d	180	static inline void __down_write_nested(struct rw_semaphore *sem, int subclass)
1da177e4 LT	181	{
	182	signed long old, new, tmp;
	183
	184	tmp = RWSEM_ACTIVE_WRITE_BIAS;
94c12cc7	185	asm volatile(
1da177e4	186	#ifndef __s390x__
94c12cc7 MS	187	" l %0,0(%3)\n"
	188	"0: lr %1,%0\n"
	189	" a %1,%5\n"
	190	" cs %0,%1,0(%3)\n"
	191	" jl 0b"
1da177e4	192	#else /* __s390x__ */
94c12cc7 MS	193	" lg %0,0(%3)\n"
	194	"0: lgr %1,%0\n"
	195	" ag %1,%5\n"
	196	" csg %0,%1,0(%3)\n"
	197	" jl 0b"
1da177e4	198	#endif /* __s390x__ */
94c12cc7	199	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	200	: "a" (&sem->count), "m" (sem->count), "m" (tmp)
94c12cc7	201	: "cc", "memory");
1da177e4 LT	202	if (old != 0)
	203	rwsem_down_write_failed(sem);
	204	}
	205
4ea2176d IM	206	static inline void __down_write(struct rw_semaphore *sem)
	207	{
	208	__down_write_nested(sem, 0);
	209	}
	210
1da177e4 LT	211	/*
	212	* trylock for writing -- returns 1 if successful, 0 if contention
	213	*/
	214	static inline int __down_write_trylock(struct rw_semaphore *sem)
	215	{
	216	signed long old;
	217
94c12cc7	218	asm volatile(
1da177e4	219	#ifndef __s390x__
94c12cc7 MS	220	" l %0,0(%2)\n"
	221	"0: ltr %0,%0\n"
	222	" jnz 1f\n"
	223	" cs %0,%4,0(%2)\n"
	224	" jl 0b\n"
1da177e4	225	#else /* __s390x__ */
94c12cc7 MS	226	" lg %0,0(%2)\n"
	227	"0: ltgr %0,%0\n"
	228	" jnz 1f\n"
	229	" csg %0,%4,0(%2)\n"
	230	" jl 0b\n"
1da177e4 LT	231	#endif /* __s390x__ */
1da177e4 LT	232	"1:"
94c12cc7	233	: "=&d" (old), "=m" (sem->count)
1da177e4	234	: "a" (&sem->count), "m" (sem->count),
94c12cc7	235	"d" (RWSEM_ACTIVE_WRITE_BIAS) : "cc", "memory");
1da177e4 LT	236	return (old == RWSEM_UNLOCKED_VALUE) ? 1 : 0;
	237	}
	238
	239	/*
	240	* unlock after reading
	241	*/
	242	static inline void __up_read(struct rw_semaphore *sem)
	243	{
	244	signed long old, new;
	245
94c12cc7	246	asm volatile(
1da177e4	247	#ifndef __s390x__
94c12cc7 MS	248	" l %0,0(%3)\n"
	249	"0: lr %1,%0\n"
	250	" ahi %1,%5\n"
	251	" cs %0,%1,0(%3)\n"
	252	" jl 0b"
1da177e4	253	#else /* __s390x__ */
94c12cc7 MS	254	" lg %0,0(%3)\n"
	255	"0: lgr %1,%0\n"
	256	" aghi %1,%5\n"
	257	" csg %0,%1,0(%3)\n"
	258	" jl 0b"
1da177e4	259	#endif /* __s390x__ */
94c12cc7	260	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4 LT	261	: "a" (&sem->count), "m" (sem->count),
1da177e4 LT	262	"i" (-RWSEM_ACTIVE_READ_BIAS)
94c12cc7	263	: "cc", "memory");
1da177e4 LT	264	if (new < 0)
	265	if ((new & RWSEM_ACTIVE_MASK) == 0)
	266	rwsem_wake(sem);
	267	}
	268
	269	/*
	270	* unlock after writing
	271	*/
	272	static inline void __up_write(struct rw_semaphore *sem)
	273	{
	274	signed long old, new, tmp;
	275
	276	tmp = -RWSEM_ACTIVE_WRITE_BIAS;
94c12cc7	277	asm volatile(
1da177e4	278	#ifndef __s390x__
94c12cc7 MS	279	" l %0,0(%3)\n"
	280	"0: lr %1,%0\n"
	281	" a %1,%5\n"
	282	" cs %0,%1,0(%3)\n"
	283	" jl 0b"
1da177e4	284	#else /* __s390x__ */
94c12cc7 MS	285	" lg %0,0(%3)\n"
	286	"0: lgr %1,%0\n"
	287	" ag %1,%5\n"
	288	" csg %0,%1,0(%3)\n"
	289	" jl 0b"
1da177e4	290	#endif /* __s390x__ */
94c12cc7	291	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	292	: "a" (&sem->count), "m" (sem->count), "m" (tmp)
94c12cc7	293	: "cc", "memory");
1da177e4 LT	294	if (new < 0)
	295	if ((new & RWSEM_ACTIVE_MASK) == 0)
	296	rwsem_wake(sem);
	297	}
	298
	299	/*
	300	* downgrade write lock to read lock
	301	*/
	302	static inline void __downgrade_write(struct rw_semaphore *sem)
	303	{
	304	signed long old, new, tmp;
	305
	306	tmp = -RWSEM_WAITING_BIAS;
94c12cc7	307	asm volatile(
1da177e4	308	#ifndef __s390x__
94c12cc7 MS	309	" l %0,0(%3)\n"
	310	"0: lr %1,%0\n"
	311	" a %1,%5\n"
	312	" cs %0,%1,0(%3)\n"
	313	" jl 0b"
1da177e4	314	#else /* __s390x__ */
94c12cc7 MS	315	" lg %0,0(%3)\n"
	316	"0: lgr %1,%0\n"
	317	" ag %1,%5\n"
	318	" csg %0,%1,0(%3)\n"
	319	" jl 0b"
1da177e4	320	#endif /* __s390x__ */
94c12cc7	321	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	322	: "a" (&sem->count), "m" (sem->count), "m" (tmp)
94c12cc7	323	: "cc", "memory");
1da177e4 LT	324	if (new > 1)
	325	rwsem_downgrade_wake(sem);
	326	}
	327
	328	/*
	329	* implement atomic add functionality
	330	*/
	331	static inline void rwsem_atomic_add(long delta, struct rw_semaphore *sem)
	332	{
	333	signed long old, new;
	334
94c12cc7	335	asm volatile(
1da177e4	336	#ifndef __s390x__
94c12cc7 MS	337	" l %0,0(%3)\n"
	338	"0: lr %1,%0\n"
	339	" ar %1,%5\n"
	340	" cs %0,%1,0(%3)\n"
	341	" jl 0b"
1da177e4	342	#else /* __s390x__ */
94c12cc7 MS	343	" lg %0,0(%3)\n"
	344	"0: lgr %1,%0\n"
	345	" agr %1,%5\n"
	346	" csg %0,%1,0(%3)\n"
	347	" jl 0b"
1da177e4	348	#endif /* __s390x__ */
94c12cc7	349	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	350	: "a" (&sem->count), "m" (sem->count), "d" (delta)
94c12cc7	351	: "cc", "memory");
1da177e4 LT	352	}
	353
	354	/*
	355	* implement exchange and add functionality
	356	*/
	357	static inline long rwsem_atomic_update(long delta, struct rw_semaphore *sem)
	358	{
	359	signed long old, new;
	360
94c12cc7	361	asm volatile(
1da177e4	362	#ifndef __s390x__
94c12cc7 MS	363	" l %0,0(%3)\n"
	364	"0: lr %1,%0\n"
	365	" ar %1,%5\n"
	366	" cs %0,%1,0(%3)\n"
	367	" jl 0b"
1da177e4	368	#else /* __s390x__ */
94c12cc7 MS	369	" lg %0,0(%3)\n"
	370	"0: lgr %1,%0\n"
	371	" agr %1,%5\n"
	372	" csg %0,%1,0(%3)\n"
	373	" jl 0b"
1da177e4	374	#endif /* __s390x__ */
94c12cc7	375	: "=&d" (old), "=&d" (new), "=m" (sem->count)
1da177e4	376	: "a" (&sem->count), "m" (sem->count), "d" (delta)
94c12cc7	377	: "cc", "memory");
1da177e4 LT	378	return new;
	379	}
	380
eb92f4ef RVR	381	static inline int rwsem_is_locked(struct rw_semaphore *sem)
	382	{
	383	return (sem->count != 0);
	384	}
	385
1da177e4 LT	386	#endif /* __KERNEL__ */
1da177e4 LT	387	#endif /* _S390_RWSEM_H */