1/* $NetBSD: lock.h,v 1.94 2024/05/12 10:45:13 rillig Exp $ */
2
3/*-
4 * Copyright (c) 1999, 2000, 2006, 2007 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 of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center, by Ross Harvey, and by Andrew Doran.
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 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33#ifndef _SYS_LOCK_H_
34#define _SYS_LOCK_H_
35
36#include <sys/stdint.h>
37#include <sys/mutex.h>
38
39#include <machine/lock.h>
40
41#ifdef _KERNEL
42
43#ifdef _KERNEL_OPT
44#include "opt_lockdebug.h"
45#endif
46
47/*
48 * From <machine/lock.h>.
49 */
50#ifndef SPINLOCK_SPIN_HOOK
51#define SPINLOCK_SPIN_HOOK
52#endif
53#ifndef SPINLOCK_BACKOFF_HOOK
54#include <sys/systm.h>
55#define SPINLOCK_BACKOFF_HOOK nullop(NULL)
56#endif
57#ifndef SPINLOCK_BACKOFF_MIN
58#define SPINLOCK_BACKOFF_MIN 4
59#endif
60#ifndef SPINLOCK_BACKOFF_MAX
61#define SPINLOCK_BACKOFF_MAX 128
62#endif
63
64#define SPINLOCK_BACKOFF(count) \
65do { \
66 int __i; \
67 for (__i = (count); __i != 0; __i--) { \
68 SPINLOCK_BACKOFF_HOOK; \
69 } \
70 if ((count) < SPINLOCK_BACKOFF_MAX) \
71 (count) += (count); \
72} while (0)
73
74#ifdef LOCKDEBUG
75#define SPINLOCK_SPINOUT(spins) ((spins)++ > 0x0fffffff)
76#else
77#define SPINLOCK_SPINOUT(spins) ((void)(spins), 0)
78#endif
79
80extern __cpu_simple_lock_t kernel_lock[];
81
82#endif /* _KERNEL */
83
84#endif /* _SYS_LOCK_H_ */