1/*	$NetBSD: lock.h,v 1.3 2008/04/28 20:23:25 martin Exp $	*/
2
3/*-
4 * Copyright (c) 2000 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * Machine-dependent spin lock operations.
34 */
35
36#ifndef _IA64_LOCK_H_
37#define	_IA64_LOCK_H_
38
39static __inline int
40__SIMPLELOCK_LOCKED_P(__cpu_simple_lock_t *__ptr)
41{
42	return *__ptr == __SIMPLELOCK_LOCKED;
43}
44
45static __inline int
46__SIMPLELOCK_UNLOCKED_P(__cpu_simple_lock_t *__ptr)
47{
48	return *__ptr == __SIMPLELOCK_UNLOCKED;
49}
50
51static __inline void
52__cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
53{
54
55	*__ptr = __SIMPLELOCK_LOCKED;
56}
57
58static __inline void
59__cpu_simple_lock_clear(__cpu_simple_lock_t *__ptr)
60{
61
62	*__ptr = __SIMPLELOCK_UNLOCKED;
63}
64
65#ifdef _KERNEL
66
67#define	SPINLOCK_SPIN_HOOK	/* nothing */
68#define	SPINLOCK_BACKOFF_HOOK	/* XXX(kochi): hint@pause */
69
70#endif
71
72static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
73	__unused;
74static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
75	__unused;
76static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
77	__unused;
78static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
79	__unused;
80
81static __inline void
82__cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
83{
84
85	*lockp = __SIMPLELOCK_UNLOCKED;
86	__insn_barrier();
87}
88
89static __inline int
90__cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
91{
92	uint8_t val;
93
94	val = __SIMPLELOCK_LOCKED;
95	__asm volatile ("xchg1 %0=[%1],%2" :
96	    "=r" (val)
97	    :"r" (lockp), "r" (val)
98	    :"memory");
99	return val == __SIMPLELOCK_UNLOCKED;
100}
101
102static __inline void
103__cpu_simple_lock(__cpu_simple_lock_t *lockp)
104{
105
106	while (!__cpu_simple_lock_try(lockp))
107		/* nothing */;
108	__insn_barrier();
109}
110
111static __inline void
112__cpu_simple_unlock(__cpu_simple_lock_t *lockp)
113{
114
115	__insn_barrier();
116	*lockp = __SIMPLELOCK_UNLOCKED;
117}
118
119#endif /* _IA64_LOCK_H_ */
120