1/*	$NetBSD: uvm_object.h,v 1.39 2020/08/14 09:06:15 chs Exp $	*/
  2
  3/*
  4 * Copyright (c) 1997 Charles D. Cranor and Washington University.
  5 * All rights reserved.
  6 *
  7 * Redistribution and use in source and binary forms, with or without
  8 * modification, are permitted provided that the following conditions
  9 * are met:
 10 * 1. Redistributions of source code must retain the above copyright
 11 *    notice, this list of conditions and the following disclaimer.
 12 * 2. Redistributions in binary form must reproduce the above copyright
 13 *    notice, this list of conditions and the following disclaimer in the
 14 *    documentation and/or other materials provided with the distribution.
 15 *
 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 26 *
 27 * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
 28 */
 29
 30#ifndef _UVM_UVM_OBJECT_H_
 31#define _UVM_UVM_OBJECT_H_
 32
 33#include <sys/queue.h>
 34#include <sys/radixtree.h>
 35#include <uvm/uvm_pglist.h>
 36
 37/*
 38 * The UVM memory object interface.  Notes:
 39 *
 40 * A UVM memory object represents a list of pages, which are managed by
 41 * the object's pager operations (uvm_object::pgops).  All pages belonging
 42 * to an object are owned by it and thus protected by the object lock.
 43 *
 44 * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
 45 * By default, the lock is allocated dynamically using mutex_obj(9) cache.
 46 * Lock sharing is normally used when there is an underlying object.  For
 47 * example, vnode representing a file may have an underlying node, which
 48 * is the case for tmpfs and layered file systems.  In such case, vnode's
 49 * UVM object and the underlying UVM object shares the lock (note that the
 50 * vnode_t::v_interlock points to uvm_object::vmobjlock).
 51 *
 52 * The reference count is managed atomically for the anonymous UVM objects.
 53 * For other objects, it is arbitrary (may use the lock or atomics).
 54 */
 55
 56struct krwlock;
 57struct uvm_object {
 58	struct krwlock *	vmobjlock;	/* lock on object */
 59	const struct uvm_pagerops *pgops;	/* pager ops */
 60	int			uo_npages;	/* # of pages in uo_pages */
 61	unsigned		uo_refs;	/* reference count */
 62	struct radix_tree	uo_pages;	/* tree of pages */
 63	LIST_HEAD(,ubc_map)	uo_ubc;		/* ubc mappings */
 64};
 65
 66/*
 67 * tags for uo_pages
 68 */
 69
 70#define	UVM_PAGE_DIRTY_TAG	1	/* might be dirty (!PG_CLEAN) */
 71#define	UVM_PAGE_WRITEBACK_TAG	2	/* being written back */
 72
 73/*
 74 * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
 75 * object is a kernel memory object rather than a normal one (kernel
 76 * memory objects don't have reference counts -- they never die).
 77 *
 78 * this value is used to detected kernel object mappings at uvm_unmap()
 79 * time.   normally when an object is unmapped its pages eventaully become
 80 * deactivated and then paged out and/or freed.    this is not useful
 81 * for kernel objects... when a kernel object is unmapped we always want
 82 * to free the resources associated with the mapping.   UVM_OBJ_KERN
 83 * allows us to decide which type of unmapping we want to do.
 84 */
 85#define UVM_OBJ_KERN		(-2)
 86
 87#define	UVM_OBJ_IS_KERN_OBJECT(uobj)					\
 88	((uobj)->uo_refs == UVM_OBJ_KERN)
 89
 90#ifdef _KERNEL
 91
 92extern const struct uvm_pagerops uvm_vnodeops;
 93extern const struct uvm_pagerops uvm_deviceops;
 94extern const struct uvm_pagerops ubc_pager;
 95extern const struct uvm_pagerops aobj_pager;
 96
 97#define	UVM_OBJ_IS_VNODE(uobj)						\
 98	((uobj)->pgops == &uvm_vnodeops)
 99
100#define	UVM_OBJ_IS_DEVICE(uobj)						\
101	((uobj)->pgops == &uvm_deviceops)
102
103#define	UVM_OBJ_IS_VTEXT(uobj)						\
104	(UVM_OBJ_IS_VNODE(uobj) && uvn_text_p(uobj))
105
106#define	UVM_OBJ_IS_CLEAN(uobj)						\
107	(UVM_OBJ_IS_VNODE(uobj) && uvm_obj_clean_p(uobj))
108
109/*
110 * UVM_OBJ_NEEDS_WRITEFAULT: true if the uobj needs to detect modification.
111 * (ie. wants to avoid writable user mappings.)
112 *
113 * XXX bad name
114 */
115
116#define	UVM_OBJ_NEEDS_WRITEFAULT(uobj)					\
117	(UVM_OBJ_IS_VNODE(uobj) && uvm_obj_clean_p(uobj))
118
119#define	UVM_OBJ_IS_AOBJ(uobj)						\
120	((uobj)->pgops == &aobj_pager)
121
122#endif /* _KERNEL */
123
124#endif /* _UVM_UVM_OBJECT_H_ */