uvm_map.h

来自「基于组件方式开发操作系统的OSKIT源代码」· C头文件 代码 · 共 518 行 · 第 1/2 页

/*	$NetBSD: uvm_map.h,v 1.22 2000/09/13 15:00:25 thorpej Exp $	*/

/* 
 * Copyright (c) 1997 Charles D. Cranor and Washington University.
 * Copyright (c) 1991, 1993, The Regents of the University of California.  
 *
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * The Mach Operating System project at Carnegie-Mellon University.
 *
 * 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 Charles D. Cranor,
 *      Washington University, 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.
 *
 *	@(#)vm_map.h    8.3 (Berkeley) 3/15/94
 * from: Id: uvm_map.h,v 1.1.2.3 1998/02/07 01:16:55 chs Exp
 *
 *
 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
 * All rights reserved.
 * 
 * Permission to use, copy, modify and distribute this software and
 * its documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 *
 *  Software Distribution Coordinator  or  [e-mail]
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 *
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 */

#ifndef _UVM_UVM_MAP_H_
#define _UVM_UVM_MAP_H_

/*
 * uvm_map.h
 */

#ifdef _KERNEL

/*
 * macros
 */

/*
 * UVM_MAP_CLIP_START: ensure that the entry begins at or after
 * the starting address, if it doesn't we split the entry.
 * 
 * => map must be locked by caller
 */

#define UVM_MAP_CLIP_START(MAP,ENTRY,VA) { \
	if ((VA) > (ENTRY)->start) uvm_map_clip_start(MAP,ENTRY,VA); }

/*
 * UVM_MAP_CLIP_END: ensure that the entry ends at or before
 *      the ending address, if it does't we split the entry.
 *
 * => map must be locked by caller
 */

#define UVM_MAP_CLIP_END(MAP,ENTRY,VA) { \
	if ((VA) < (ENTRY)->end) uvm_map_clip_end(MAP,ENTRY,VA); }

/*
 * extract flags
 */
#define UVM_EXTRACT_REMOVE	0x1	/* remove mapping from old map */
#define UVM_EXTRACT_CONTIG	0x2	/* try to keep it contig */
#define UVM_EXTRACT_QREF	0x4	/* use quick refs */
#define UVM_EXTRACT_FIXPROT	0x8	/* set prot to maxprot as we go */

#endif /* _KERNEL */

#include <uvm/uvm_anon.h>

/*
 * types defined:
 *
 *	vm_map_t		the high-level address map data structure.
 *	vm_map_entry_t		an entry in an address map.
 *	vm_map_version_t	a timestamp of a map, for use with vm_map_lookup
 */

/*
 * Objects which live in maps may be either VM objects, or another map
 * (called a "sharing map") which denotes read-write sharing with other maps.
 *
 * XXXCDC: private pager data goes here now
 */

union vm_map_object {
	struct uvm_object	*uvm_obj;	/* UVM OBJECT */
	struct vm_map		*sub_map;	/* belongs to another map */
};

/*
 * Address map entries consist of start and end addresses,
 * a VM object (or sharing map) and offset into that object,
 * and user-exported inheritance and protection information.
 * Also included is control information for virtual copy operations.
 */
struct vm_map_entry {
	struct vm_map_entry	*prev;		/* previous entry */
	struct vm_map_entry	*next;		/* next entry */
	vaddr_t			start;		/* start address */
	vaddr_t			end;		/* end address */
	union vm_map_object	object;		/* object I point to */
	voff_t			offset;		/* offset into object */
	int			etype;		/* entry type */
	vm_prot_t		protection;	/* protection code */
	vm_prot_t		max_protection;	/* maximum protection */
	vm_inherit_t		inheritance;	/* inheritance */
	int			wired_count;	/* can be paged if == 0 */
	struct vm_aref		aref;		/* anonymous overlay */
	int			advice;		/* madvise advice */
#define uvm_map_entry_stop_copy flags
	u_int8_t		flags;		/* flags */

#define UVM_MAP_STATIC		0x01		/* static map entry */

};

#define	VM_MAPENT_ISWIRED(entry)	((entry)->wired_count != 0)

/*
 *	Maps are doubly-linked lists of map entries, kept sorted
 *	by address.  A single hint is provided to start
 *	searches again from the last successful search,
 *	insertion, or removal.
 *
 *	LOCKING PROTOCOL NOTES:
 *	-----------------------
 *
 *	VM map locking is a little complicated.  There are both shared
 *	and exclusive locks on maps.  However, it is sometimes required
 *	to downgrade an exclusive lock to a shared lock, and upgrade to
 *	an exclusive lock again (to perform error recovery).  However,
 *	another thread *must not* queue itself to receive an exclusive
 *	lock while before we upgrade back to exclusive, otherwise the
 *	error recovery becomes extremely difficult, if not impossible.
 *
 *	In order to prevent this scenario, we introduce the notion of
 *	a `busy' map.  A `busy' map is read-locked, but other threads
 *	attempting to write-lock wait for this flag to clear before
 *	entering the lock manager.  A map may only be marked busy
 *	when the map is write-locked (and then the map must be downgraded
 *	to read-locked), and may only be marked unbusy by the thread
 *	which marked it busy (holding *either* a read-lock or a
 *	write-lock, the latter being gained by an upgrade).
 *
 *	Access to the map `flags' member is controlled by the `flags_lock'
 *	simple lock.  Note that some flags are static (set once at map
 *	creation time, and never changed), and thus require no locking
 *	to check those flags.  All flags which are r/w must be set or
 *	cleared while the `flags_lock' is asserted.  Additional locking
 *	requirements are:
 *
 *		VM_MAP_PAGEABLE		r/o static flag; no locking required
 *
 *		VM_MAP_INTRSAFE		r/o static flag; no locking required
 *
 *		VM_MAP_WIREFUTURE	r/w; may only be set or cleared when
 *					map is write-locked.  may be tested
 *					without asserting `flags_lock'.
 *
 *		VM_MAP_BUSY		r/w; may only be set when map is
 *					write-locked, may only be cleared by
 *					thread which set it, map read-locked
 *					or write-locked.  must be tested
 *					while `flags_lock' is asserted.
 *
 *		VM_MAP_WANTLOCK		r/w; may only be set when the map
 *					is busy, and thread is attempting
 *					to write-lock.  must be tested
 *					while `flags_lock' is asserted.
 */
struct vm_map {
	struct pmap *		pmap;		/* Physical map */
	lock_data_t		lock;		/* Lock for map data */
	struct vm_map_entry	header;		/* List of entries */
	int			nentries;	/* Number of entries */
	vsize_t			size;		/* virtual size */
	int			ref_count;	/* Reference count */
	simple_lock_data_t	ref_lock;	/* Lock for ref_count field */
	vm_map_entry_t		hint;		/* hint for quick lookups */
	simple_lock_data_t	hint_lock;	/* lock for hint storage */
	vm_map_entry_t		first_free;	/* First free space hint */
	int			flags;		/* flags */
	simple_lock_data_t	flags_lock;	/* Lock for flags field */
	unsigned int		timestamp;	/* Version number */
#define	min_offset		header.start
#define max_offset		header.end
};

/* vm_map flags */
#define	VM_MAP_PAGEABLE		0x01		/* ro: entries are pageable */
#define	VM_MAP_INTRSAFE		0x02		/* ro: interrupt safe map */
#define	VM_MAP_WIREFUTURE	0x04		/* rw: wire future mappings */
#define	VM_MAP_BUSY		0x08		/* rw: map is busy */
#define	VM_MAP_WANTLOCK		0x10		/* rw: want to write-lock */

/* XXX: number of kernel maps and entries to statically allocate */

#if !defined(MAX_KMAPENT)
#if (50 + (2 * NPROC) > 1000)
#define MAX_KMAPENT (50 + (2 * NPROC))
#else
#define	MAX_KMAPENT	1000  /* XXXCDC: no crash */
#endif
#endif	/* !defined MAX_KMAPENT */

#ifdef _KERNEL
#define	vm_map_modflags(map, set, clear)				\
do {									\
	simple_lock(&(map)->flags_lock);				\
	(map)->flags = ((map)->flags | (set)) & ~(clear);		\
	simple_unlock(&(map)->flags_lock);				\
} while (0)
#endif /* _KERNEL */

/*