1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
/* $OpenBSD: lock.h,v 1.6 2008/06/26 05:42:10 ray Exp $ */
/* $NetBSD: lock.h,v 1.1.2.2 2000/05/03 14:40:55 sommerfeld Exp $ */
/*-
* Copyright (c) 2000 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Jason R. Thorpe.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
/*
* Machine-dependent spin lock operations.
*/
#ifndef _I386_LOCK_H_
#define _I386_LOCK_H_
typedef __volatile int __cpu_simple_lock_t;
#define __SIMPLELOCK_LOCKED 1
#define __SIMPLELOCK_UNLOCKED 0
/*
* compiler barrier: prevent reordering of instructions.
* XXX something similar will move to <sys/cdefs.h>
* or thereabouts.
* This prevents the compiler from reordering code around
* this "instruction", acting as a sequence point for code generation.
*/
#define __lockbarrier() __asm __volatile("": : :"memory")
#define SPINLOCK_SPIN_HOOK __asm __volatile("pause": : :"memory")
#ifdef LOCKDEBUG
extern void __cpu_simple_lock_init(__cpu_simple_lock_t *);
extern void __cpu_simple_lock(__cpu_simple_lock_t *);
extern int __cpu_simple_lock_try(__cpu_simple_lock_t *);
extern void __cpu_simple_unlock(__cpu_simple_lock_t *);
#else
#include <machine/atomic.h>
static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
__attribute__((__unused__));
static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
__attribute__((__unused__));
static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
__attribute__((__unused__));
static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
__attribute__((__unused__));
static __inline void
__cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
{
*lockp = __SIMPLELOCK_UNLOCKED;
__lockbarrier();
}
static __inline void
__cpu_simple_lock(__cpu_simple_lock_t *lockp)
{
while (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
== __SIMPLELOCK_LOCKED)
SPINLOCK_SPIN_HOOK;
__lockbarrier();
}
static __inline int
__cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
{
int r = (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
== __SIMPLELOCK_UNLOCKED);
__lockbarrier();
return (r);
}
static __inline void
__cpu_simple_unlock(__cpu_simple_lock_t *lockp)
{
__lockbarrier();
*lockp = __SIMPLELOCK_UNLOCKED;
}
#endif /* !LOCKDEBUG */
#ifdef _KERNEL
extern int rw_cas_486(volatile unsigned long *, unsigned long, unsigned long);
#define rw_cas rw_cas_486
#endif
#endif /* _I386_LOCK_H_ */
|
