lock.h revision 1.10 
1/*	$NetBSD: lock.h,v 1.10 2023/10/06 11:45:37 skrll 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(const __cpu_simple_lock_t *__ptr)
41{
42	return *__ptr == __SIMPLELOCK_LOCKED;
43}
44
45static __inline int
46__SIMPLELOCK_UNLOCKED_P(const __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 ia64_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}
87
88static __inline int
89__cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
90{
91	uint8_t val;
92
93	val = __SIMPLELOCK_LOCKED;
94	__asm volatile ("xchg1 %0=[%1],%2" :
95	    "=r" (val)
96	    :"r" (lockp), "r" (val)
97	    :"memory");
98	return val == __SIMPLELOCK_UNLOCKED;
99}
100
101static __inline void
102__cpu_simple_lock(__cpu_simple_lock_t *lockp)
103{
104
105	while (!__cpu_simple_lock_try(lockp))
106		/* nothing */;
107	__insn_barrier();
108}
109
110static __inline void
111__cpu_simple_unlock(__cpu_simple_lock_t *lockp)
112{
113
114	__insn_barrier();
115	*lockp = __SIMPLELOCK_UNLOCKED;
116}
117
118static __inline void
119ia64_pause(void)
120{
121	__asm __volatile("hint @pause" ::: "memory");
122}
123
124#endif /* _IA64_LOCK_H_ */
125