1/* $NetBSD: uvm_fault_i.h,v 1.33 2020/02/23 15:46:43 ad 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_fault_i.h,v 1.1.6.1 1997/12/08 16:07:12 chuck Exp
28 */
29
30#ifndef _UVM_UVM_FAULT_I_H_
31#define _UVM_UVM_FAULT_I_H_
32
33/*
34 * uvm_fault_i.h: fault inline functions
35 */
36void uvmfault_update_stats(struct uvm_faultinfo *);
37
38
39/*
40 * uvmfault_unlockmaps: unlock the maps
41 */
42
43static __inline void
44uvmfault_unlockmaps(struct uvm_faultinfo *ufi, bool write_locked)
45{
46 /*
47 * ufi can be NULL when this isn't really a fault,
48 * but merely paging in anon data.
49 */
50
51 if (ufi == NULL) {
52 return;
53 }
54
55#ifndef __HAVE_NO_PMAP_STATS
56 uvmfault_update_stats(ufi);
57#endif
58 if (write_locked) {
59 vm_map_unlock(ufi->map);
60 } else {
61 vm_map_unlock_read(ufi->map);
62 }
63}
64
65/*
66 * uvmfault_unlockall: unlock everything passed in.
67 *
68 * => maps must be read-locked (not write-locked).
69 */
70
71static __inline void
72uvmfault_unlockall(struct uvm_faultinfo *ufi, struct vm_amap *amap,
73 struct uvm_object *uobj)
74{
75
76 if (uobj)
77 rw_exit(uobj->vmobjlock);
78 if (amap)
79 amap_unlock(amap);
80 uvmfault_unlockmaps(ufi, false);
81}
82
83/*
84 * uvmfault_lookup: lookup a virtual address in a map
85 *
86 * => caller must provide a uvm_faultinfo structure with the IN
87 * params properly filled in
88 * => we will lookup the map entry (handling submaps) as we go
89 * => if the lookup is a success we will return with the maps locked
90 * => if "write_lock" is true, we write_lock the map, otherwise we only
91 * get a read lock.
92 * => note that submaps can only appear in the kernel and they are
93 * required to use the same virtual addresses as the map they
94 * are referenced by (thus address translation between the main
95 * map and the submap is unnecessary).
96 */
97
98static __inline bool
99uvmfault_lookup(struct uvm_faultinfo *ufi, bool write_lock)
100{
101 struct vm_map *tmpmap;
102
103 /*
104 * init ufi values for lookup.
105 */
106
107 ufi->map = ufi->orig_map;
108 ufi->size = ufi->orig_size;
109
110 /*
111 * keep going down levels until we are done. note that there can
112 * only be two levels so we won't loop very long.
113 */
114
115 for (;;) {
116 /*
117 * lock map
118 */
119 if (write_lock) {
120 vm_map_lock(ufi->map);
121 } else {
122 vm_map_lock_read(ufi->map);
123 }
124
125 /*
126 * lookup
127 */
128 if (!uvm_map_lookup_entry(ufi->map, ufi->orig_rvaddr,
129 &ufi->entry)) {
130 uvmfault_unlockmaps(ufi, write_lock);
131 return(false);
132 }
133
134 /*
135 * reduce size if necessary
136 */
137 if (ufi->entry->end - ufi->orig_rvaddr < ufi->size)
138 ufi->size = ufi->entry->end - ufi->orig_rvaddr;
139
140 /*
141 * submap? replace map with the submap and lookup again.
142 * note: VAs in submaps must match VAs in main map.
143 */
144 if (UVM_ET_ISSUBMAP(ufi->entry)) {
145 tmpmap = ufi->entry->object.sub_map;
146 if (write_lock) {
147 vm_map_unlock(ufi->map);
148 } else {
149 vm_map_unlock_read(ufi->map);
150 }
151 ufi->map = tmpmap;
152 continue;
153 }
154
155 /*
156 * got it!
157 */
158
159 ufi->mapv = ufi->map->timestamp;
160 return(true);
161
162 } /* while loop */
163
164 /*NOTREACHED*/
165}
166
167/*
168 * uvmfault_relock: attempt to relock the same version of the map
169 *
170 * => fault data structures should be unlocked before calling.
171 * => if a success (true) maps will be locked after call.
172 */
173
174static __inline bool
175uvmfault_relock(struct uvm_faultinfo *ufi)
176{
177 /*
178 * ufi can be NULL when this isn't really a fault,
179 * but merely paging in anon data.
180 */
181
182 if (ufi == NULL) {
183 return true;
184 }
185
186 cpu_count(CPU_COUNT_FLTRELCK, 1);
187
188 /*
189 * relock map. fail if version mismatch (in which case nothing
190 * gets locked).
191 */
192
193 vm_map_lock_read(ufi->map);
194 if (ufi->mapv != ufi->map->timestamp) {
195 vm_map_unlock_read(ufi->map);
196 return(false);
197 }
198
199 cpu_count(CPU_COUNT_FLTRELCKOK, 1);
200 return(true);
201}
202
203#endif /* _UVM_UVM_FAULT_I_H_ */