Annotation of sys/arch/i386/include/lock.h, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: lock.h,v 1.5 2007/05/29 18:18:20 tom Exp $ */
2: /* $NetBSD: lock.h,v 1.1.2.2 2000/05/03 14:40:55 sommerfeld Exp $ */
3:
4: /*-
5: * Copyright (c) 2000 The NetBSD Foundation, Inc.
6: * All rights reserved.
7: *
8: * This code is derived from software contributed to The NetBSD Foundation
9: * by Jason R. Thorpe.
10: *
11: * Redistribution and use in source and binary forms, with or without
12: * modification, are permitted provided that the following conditions
13: * are met:
14: * 1. Redistributions of source code must retain the above copyright
15: * notice, this list of conditions and the following disclaimer.
16: * 2. Redistributions in binary form must reproduce the above copyright
17: * notice, this list of conditions and the following disclaimer in the
18: * documentation and/or other materials provided with the distribution.
19: * 3. All advertising materials mentioning features or use of this software
20: * must display the following acknowledgement:
21: * This product includes software developed by the NetBSD
22: * Foundation, Inc. and its contributors.
23: * 4. Neither the name of The NetBSD Foundation nor the names of its
24: * contributors may be used to endorse or promote products derived
25: * from this software without specific prior written permission.
26: *
27: * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37: * POSSIBILITY OF SUCH DAMAGE.
38: */
39:
40: /*
41: * Machine-dependent spin lock operations.
42: */
43:
44: #ifndef _I386_LOCK_H_
45: #define _I386_LOCK_H_
46:
47: typedef __volatile int __cpu_simple_lock_t;
48:
49: #define __SIMPLELOCK_LOCKED 1
50: #define __SIMPLELOCK_UNLOCKED 0
51:
52: /*
53: * compiler barrier: prevent reordering of instructions.
54: * XXX something similar will move to <sys/cdefs.h>
55: * or thereabouts.
56: * This prevents the compiler from reordering code around
57: * this "instruction", acting as a sequence point for code generation.
58: */
59:
60: #define __lockbarrier() __asm __volatile("": : :"memory")
61:
62: #define SPINLOCK_SPIN_HOOK __asm __volatile("pause": : :"memory")
63:
64: #ifdef LOCKDEBUG
65:
66: extern void __cpu_simple_lock_init(__cpu_simple_lock_t *);
67: extern void __cpu_simple_lock(__cpu_simple_lock_t *);
68: extern int __cpu_simple_lock_try(__cpu_simple_lock_t *);
69: extern void __cpu_simple_unlock(__cpu_simple_lock_t *);
70:
71: #else
72:
73: #include <machine/atomic.h>
74:
75: static __inline void __cpu_simple_lock_init(__cpu_simple_lock_t *)
76: __attribute__((__unused__));
77: static __inline void __cpu_simple_lock(__cpu_simple_lock_t *)
78: __attribute__((__unused__));
79: static __inline int __cpu_simple_lock_try(__cpu_simple_lock_t *)
80: __attribute__((__unused__));
81: static __inline void __cpu_simple_unlock(__cpu_simple_lock_t *)
82: __attribute__((__unused__));
83:
84: static __inline void
85: __cpu_simple_lock_init(__cpu_simple_lock_t *lockp)
86: {
87: *lockp = __SIMPLELOCK_UNLOCKED;
88: __lockbarrier();
89: }
90:
91: static __inline void
92: __cpu_simple_lock(__cpu_simple_lock_t *lockp)
93: {
94: while (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
95: == __SIMPLELOCK_LOCKED)
96: SPINLOCK_SPIN_HOOK;
97: __lockbarrier();
98: }
99:
100: static __inline int
101: __cpu_simple_lock_try(__cpu_simple_lock_t *lockp)
102: {
103: int r = (i386_atomic_testset_i(lockp, __SIMPLELOCK_LOCKED)
104: == __SIMPLELOCK_UNLOCKED);
105:
106: __lockbarrier();
107:
108: return (r);
109: }
110:
111: static __inline void
112: __cpu_simple_unlock(__cpu_simple_lock_t *lockp)
113: {
114: __lockbarrier();
115: *lockp = __SIMPLELOCK_UNLOCKED;
116: }
117:
118: #endif /* !LOCKDEBUG */
119:
120: #ifdef _KERNEL
121: extern int rw_cas_486(volatile unsigned long *, unsigned long, unsigned long);
122: #define rw_cas rw_cas_486
123: #endif
124:
125: #endif /* _I386_LOCK_H_ */
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