1/* $OpenBSD: uvm_object.h,v 1.30 2022/09/04 06:49:11 jsg Exp $ */
2/* $NetBSD: uvm_object.h,v 1.11 2001/03/09 01:02:12 chs Exp $ */
3
4/*
5 * Copyright (c) 1997 Charles D. Cranor and Washington University.
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * from: Id: uvm_object.h,v 1.1.2.2 1998/01/04 22:44:51 chuck Exp
29 */
30
31#ifndef _UVM_UVM_OBJECT_H_
32#define _UVM_UVM_OBJECT_H_
33
34/*
35 * The UVM memory object interface. Notes:
36 *
37 * A UVM memory object represents a list of pages, which are managed by
38 * the object's pager operations (uvm_object::pgops). All pages belonging
39 * to an object are owned by it and thus protected by the object lock.
40 *
41 * The lock (uvm_object::vmobjlock) may be shared amongst the UVM objects.
42 * By default, the lock is allocated dynamically using rw_obj_init() cache.
43 * Lock sharing is normally used when there is an underlying object. For
44 * example, vnode representing a file may have an underlying node, which
45 * is the case for tmpfs and layered file systems. In such case, vnode's
46 * UVM object and the underlying UVM object shares the lock.
47 *
48 * The reference count is managed atomically for the anonymous UVM objects.
49 * For other objects, it is arbitrary (may use the lock or atomics).
50 */
51
52struct uvm_object {
53 struct rwlock *vmobjlock; /* lock on object */
54 const struct uvm_pagerops *pgops; /* pager ops */
55 RBT_HEAD(uvm_objtree, vm_page) memt; /* pages in object */
56 int uo_npages; /* # of pages in memt */
57 int uo_refs; /* reference count */
58};
59
60/*
61 * UVM_OBJ_KERN is a 'special' uo_refs value which indicates that the
62 * object is a kernel memory object rather than a normal one (kernel
63 * memory objects don't have reference counts -- they never die).
64 *
65 * this value is used to detected kernel object mappings at uvm_unmap()
66 * time. normally when an object is unmapped its pages eventually become
67 * deactivated and then paged out and/or freed. this is not useful
68 * for kernel objects... when a kernel object is unmapped we always want
69 * to free the resources associated with the mapping. UVM_OBJ_KERN
70 * allows us to decide which type of unmapping we want to do.
71 *
72 * in addition, we have kernel objects which may be used in an
73 * interrupt context. these objects get their mappings entered
74 * with pmap_kenter*() and removed with pmap_kremove(), which
75 * are safe to call in interrupt context, and must be used ONLY
76 * for wired kernel mappings in these objects and their associated
77 * maps.
78 */
79#define UVM_OBJ_KERN (-2)
80
81#define UVM_OBJ_IS_KERN_OBJECT(uobj) \
82 ((uobj)->uo_refs == UVM_OBJ_KERN)
83
84#ifdef _KERNEL
85
86extern const struct uvm_pagerops uvm_vnodeops;
87extern const struct uvm_pagerops uvm_deviceops;
88extern const struct uvm_pagerops pmap_pager;
89extern const struct uvm_pagerops bufcache_pager;
90
91/* For object trees */
92int uvm_pagecmp(const struct vm_page *, const struct vm_page *);
93RBT_PROTOTYPE(uvm_objtree, vm_page, objt, uvm_pagecmp)
94
95#define UVM_OBJ_IS_VNODE(uobj) \
96 ((uobj)->pgops == &uvm_vnodeops)
97
98#define UVM_OBJ_IS_DEVICE(uobj) \
99 ((uobj)->pgops == &uvm_deviceops)
100
101#define UVM_OBJ_IS_VTEXT(uobj) \
102 ((uobj)->pgops == &uvm_vnodeops && \
103 ((struct vnode *)uobj)->v_flag & VTEXT)
104
105#define UVM_OBJ_IS_AOBJ(uobj) \
106 ((uobj)->pgops == &aobj_pager)
107
108#define UVM_OBJ_IS_PMAP(uobj) \
109 ((uobj)->pgops == &pmap_pager)
110
111#define UVM_OBJ_IS_BUFCACHE(uobj) \
112 ((uobj)->pgops == &bufcache_pager)
113
114#define UVM_OBJ_IS_DUMMY(uobj) \
115 (UVM_OBJ_IS_PMAP(uobj) || UVM_OBJ_IS_BUFCACHE(uobj))
116
117void uvm_obj_init(struct uvm_object *, const struct uvm_pagerops *, int);
118void uvm_obj_destroy(struct uvm_object *);
119void uvm_obj_setlock(struct uvm_object *, struct rwlock *);
120int uvm_obj_wire(struct uvm_object *, voff_t, voff_t, struct pglist *);
121void uvm_obj_unwire(struct uvm_object *, voff_t, voff_t);
122void uvm_obj_free(struct uvm_object *);
123
124#endif /* _KERNEL */
125
126#endif /* _UVM_UVM_OBJECT_H_ */