1 /* $NetBSD: uvm_fault_i.h,v 1.28 2012/02/19 00:05:56 rmind 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 */
36
37 /*
38 * uvmfault_unlockmaps: unlock the maps
39 */
40
41 static inline void
uvmfault_unlockmaps(struct uvm_faultinfo * ufi,bool write_locked)42 uvmfault_unlockmaps(struct uvm_faultinfo *ufi, bool write_locked)
43 {
44 /*
45 * ufi can be NULL when this isn't really a fault,
46 * but merely paging in anon data.
47 */
48
49 if (ufi == NULL) {
50 return;
51 }
52
53 if (write_locked) {
54 vm_map_unlock(ufi->map);
55 } else {
56 vm_map_unlock_read(ufi->map);
57 }
58 }
59
60 /*
61 * uvmfault_unlockall: unlock everything passed in.
62 *
63 * => maps must be read-locked (not write-locked).
64 */
65
66 static inline void
uvmfault_unlockall(struct uvm_faultinfo * ufi,struct vm_amap * amap,struct uvm_object * uobj)67 uvmfault_unlockall(struct uvm_faultinfo *ufi, struct vm_amap *amap,
68 struct uvm_object *uobj)
69 {
70
71 if (uobj)
72 mutex_exit(uobj->vmobjlock);
73 if (amap)
74 amap_unlock(amap);
75 uvmfault_unlockmaps(ufi, false);
76 }
77
78 /*
79 * uvmfault_lookup: lookup a virtual address in a map
80 *
81 * => caller must provide a uvm_faultinfo structure with the IN
82 * params properly filled in
83 * => we will lookup the map entry (handling submaps) as we go
84 * => if the lookup is a success we will return with the maps locked
85 * => if "write_lock" is true, we write_lock the map, otherwise we only
86 * get a read lock.
87 * => note that submaps can only appear in the kernel and they are
88 * required to use the same virtual addresses as the map they
89 * are referenced by (thus address translation between the main
90 * map and the submap is unnecessary).
91 */
92
93 static inline bool
uvmfault_lookup(struct uvm_faultinfo * ufi,bool write_lock)94 uvmfault_lookup(struct uvm_faultinfo *ufi, bool write_lock)
95 {
96 struct vm_map *tmpmap;
97
98 /*
99 * init ufi values for lookup.
100 */
101
102 ufi->map = ufi->orig_map;
103 ufi->size = ufi->orig_size;
104
105 /*
106 * keep going down levels until we are done. note that there can
107 * only be two levels so we won't loop very long.
108 */
109
110 for (;;) {
111 /*
112 * lock map
113 */
114 if (write_lock) {
115 vm_map_lock(ufi->map);
116 } else {
117 vm_map_lock_read(ufi->map);
118 }
119
120 /*
121 * lookup
122 */
123 if (!uvm_map_lookup_entry(ufi->map, ufi->orig_rvaddr,
124 &ufi->entry)) {
125 uvmfault_unlockmaps(ufi, write_lock);
126 return(false);
127 }
128
129 /*
130 * reduce size if necessary
131 */
132 if (ufi->entry->end - ufi->orig_rvaddr < ufi->size)
133 ufi->size = ufi->entry->end - ufi->orig_rvaddr;
134
135 /*
136 * submap? replace map with the submap and lookup again.
137 * note: VAs in submaps must match VAs in main map.
138 */
139 if (UVM_ET_ISSUBMAP(ufi->entry)) {
140 tmpmap = ufi->entry->object.sub_map;
141 if (write_lock) {
142 vm_map_unlock(ufi->map);
143 } else {
144 vm_map_unlock_read(ufi->map);
145 }
146 ufi->map = tmpmap;
147 continue;
148 }
149
150 /*
151 * got it!
152 */
153
154 ufi->mapv = ufi->map->timestamp;
155 return(true);
156
157 } /* while loop */
158
159 /*NOTREACHED*/
160 }
161
162 /*
163 * uvmfault_relock: attempt to relock the same version of the map
164 *
165 * => fault data structures should be unlocked before calling.
166 * => if a success (true) maps will be locked after call.
167 */
168
169 static inline bool
uvmfault_relock(struct uvm_faultinfo * ufi)170 uvmfault_relock(struct uvm_faultinfo *ufi)
171 {
172 /*
173 * ufi can be NULL when this isn't really a fault,
174 * but merely paging in anon data.
175 */
176
177 if (ufi == NULL) {
178 return true;
179 }
180
181 uvmexp.fltrelck++;
182
183 /*
184 * relock map. fail if version mismatch (in which case nothing
185 * gets locked).
186 */
187
188 vm_map_lock_read(ufi->map);
189 if (ufi->mapv != ufi->map->timestamp) {
190 vm_map_unlock_read(ufi->map);
191 return(false);
192 }
193
194 uvmexp.fltrelckok++;
195 return(true);
196 }
197
198 #endif /* _UVM_UVM_FAULT_I_H_ */
199