map.h

基于组件方式开发操作系统的OSKIT源代码

/*	$NetBSD: map.h,v 1.14 1998/02/05 08:00:41 mrg Exp $	*/

/*-
 * Copyright (c) 1982, 1986, 1993
 *	The Regents of the University of California.  All rights reserved.
 * (c) UNIX System Laboratories, Inc.
 * All or some portions of this file are derived from material licensed
 * to the University of California by American Telephone and Telegraph
 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
 * the permission of UNIX System Laboratories, Inc.
 *
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 *
 *	@(#)map.h	8.3 (Berkeley) 1/26/94
 */

#ifndef _SYS_MAP_H_
#define _SYS_MAP_H_

/*
 * Resource allocation maps.
 *
 * Associated routines manage sub-allocation of an address space using
 * an array of segment descriptors.  The first element of this array
 * is a map structure, describing the arrays extent and the name
 * of the controlled object.  Each additional structure represents
 * a free segment of the address space.
 *
 * A call to rminit initializes a resource map.  Later on, rmfree may be used
 * to free some more address space for the map.  Subsequent calls to rmalloc
 * and rmfree allocate and free space in the resource map.  If the resource
 * map becomes too fragmented to be described in the available space,
 * then some of the resource is discarded.  This may lead to critical
 * shortages, but is better than not checking (as the previous versions
 * of these routines did) or giving up and calling panic().  The routines
 * could use linked lists and call a memory allocator when they run
 * out of space, but that would not solve the out of space problem when
 * called at interrupt time.
 *
 * N.B.: The address 0 in the resource address space is not available
 * as it is used internally by the resource map routines.
 */
struct map {
	struct	mapent *m_limit;	/* first slot beyond map */
	char	*m_name;		/* name of resource, for messages */
};

struct mapent {
	long	m_size;			/* size of this segment of the map */
	long	m_addr;			/* start of segment */
};

#ifdef _KERNEL

long	rmalloc __P((struct map *, long));
void	rmfree __P((struct map *, long, long));
void	rminit __P((struct map *, long, long, char *, int));
#endif /* _KERNEL */

#endif /* !_SYS_MAP_H_ */