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
39 static __inline int
__SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t * __ptr)40 __SIMPLELOCK_LOCKED_P(const __cpu_simple_lock_t *__ptr)
41 {
42 return *__ptr == __SIMPLELOCK_LOCKED;
43 }
44
45 static __inline int
__SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t * __ptr)46 __SIMPLELOCK_UNLOCKED_P(const __cpu_simple_lock_t *__ptr)
47 {
48 return *__ptr == __SIMPLELOCK_UNLOCKED;
49 }
50
51 static __inline void
__cpu_simple_lock_set(__cpu_simple_lock_t * __ptr)52 __cpu_simple_lock_set(__cpu_simple_lock_t *__ptr)
53 {
54
55 *__ptr = __SIMPLELOCK_LOCKED;
56 }
57
58 static __inline void
__cpu_simple_lock_clear(__cpu_simple_lock_t * __ptr)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
72 static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
73 __unused;
74 static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
75 __unused;
76 static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
77 __unused;
78 static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
79 __unused;
80
81 static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t * lockp)82 __cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
83 {
84
85 *lockp = __SIMPLELOCK_UNLOCKED;
86 }
87
88 static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t * lockp)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
101 static __inline void
__cpu_simple_lock(__cpu_simple_lock_t * lockp)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
110 static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t * lockp)111 __cpu_simple_unlock(__cpu_simple_lock_t *lockp)
112 {
113
114 __insn_barrier();
115 *lockp = __SIMPLELOCK_UNLOCKED;
116 }
117
118 static __inline void
ia64_pause(void)119 ia64_pause(void)
120 {
121 __asm __volatile("hint @pause" ::: "memory");
122 }
123
124 #endif /* _IA64_LOCK_H_ */
125