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 |
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 |
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 |
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 |
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 | |