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| 1 | 13 | up20180614 | /* $NetBSD: uvm_fault_i.h,v 1.28 2012/02/19 00:05:56 rmind Exp $ */
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| 2 | |||
| 3 | /*
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| 4 | * Copyright (c) 1997 Charles D. Cranor and Washington University.
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| 5 | * All rights reserved.
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| 6 | *
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| 7 | * Redistribution and use in source and binary forms, with or without
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| 8 | * modification, are permitted provided that the following conditions
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| 9 | * are met:
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| 10 | * 1. Redistributions of source code must retain the above copyright
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| 11 | * notice, this list of conditions and the following disclaimer.
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| 12 | * 2. Redistributions in binary form must reproduce the above copyright
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| 13 | * notice, this list of conditions and the following disclaimer in the
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| 14 | * documentation and/or other materials provided with the distribution.
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| 15 | *
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| 16 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 17 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 18 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 19 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 20 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 21 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 22 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 23 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 24 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 25 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 26 | *
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| 27 | * from: Id: uvm_fault_i.h,v 1.1.6.1 1997/12/08 16:07:12 chuck Exp
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| 28 | */
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| 29 | |||
| 30 | #ifndef _UVM_UVM_FAULT_I_H_
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| 31 | #define _UVM_UVM_FAULT_I_H_
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| 32 | |||
| 33 | /*
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| 34 | * uvm_fault_i.h: fault inline functions
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| 35 | */
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| 36 | |||
| 37 | /*
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| 38 | * uvmfault_unlockmaps: unlock the maps
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| 39 | */
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| 40 | |||
| 41 | static inline void |
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| 42 | uvmfault_unlockmaps(struct uvm_faultinfo *ufi, bool write_locked) |
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| 43 | {
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| 44 | /*
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| 45 | * ufi can be NULL when this isn't really a fault,
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| 46 | * but merely paging in anon data.
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| 47 | */
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| 48 | |||
| 49 | if (ufi == NULL) { |
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| 50 | return;
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| 51 | } |
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| 52 | |||
| 53 | if (write_locked) {
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| 54 | vm_map_unlock(ufi->map); |
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| 55 | } else {
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| 56 | vm_map_unlock_read(ufi->map); |
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| 57 | } |
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| 58 | } |
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| 59 | |||
| 60 | /*
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| 61 | * uvmfault_unlockall: unlock everything passed in.
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| 62 | *
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| 63 | * => maps must be read-locked (not write-locked).
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| 64 | */
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| 65 | |||
| 66 | static inline void |
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| 67 | uvmfault_unlockall(struct uvm_faultinfo *ufi, struct vm_amap *amap, |
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| 68 | struct uvm_object *uobj)
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| 69 | {
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| 70 | |||
| 71 | if (uobj)
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| 72 | mutex_exit(uobj->vmobjlock); |
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| 73 | if (amap)
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| 74 | amap_unlock(amap); |
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| 75 | uvmfault_unlockmaps(ufi, false);
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| 76 | } |
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| 77 | |||
| 78 | /*
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| 79 | * uvmfault_lookup: lookup a virtual address in a map
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| 80 | *
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| 81 | * => caller must provide a uvm_faultinfo structure with the IN
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| 82 | * params properly filled in
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| 83 | * => we will lookup the map entry (handling submaps) as we go
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| 84 | * => if the lookup is a success we will return with the maps locked
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| 85 | * => if "write_lock" is true, we write_lock the map, otherwise we only
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| 86 | * get a read lock.
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| 87 | * => note that submaps can only appear in the kernel and they are
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| 88 | * required to use the same virtual addresses as the map they
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| 89 | * are referenced by (thus address translation between the main
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| 90 | * map and the submap is unnecessary).
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| 91 | */
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| 92 | |||
| 93 | static inline bool |
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| 94 | uvmfault_lookup(struct uvm_faultinfo *ufi, bool write_lock) |
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| 95 | {
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| 96 | struct vm_map *tmpmap;
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| 97 | |||
| 98 | /*
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| 99 | * init ufi values for lookup.
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| 100 | */
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| 101 | |||
| 102 | ufi->map = ufi->orig_map; |
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| 103 | ufi->size = ufi->orig_size; |
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| 104 | |||
| 105 | /*
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| 106 | * keep going down levels until we are done. note that there can
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| 107 | * only be two levels so we won't loop very long.
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| 108 | */
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| 109 | |||
| 110 | for (;;) {
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| 111 | /*
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| 112 | * lock map
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| 113 | */
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| 114 | if (write_lock) {
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| 115 | vm_map_lock(ufi->map); |
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| 116 | } else {
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| 117 | vm_map_lock_read(ufi->map); |
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| 118 | } |
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| 119 | |||
| 120 | /*
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| 121 | * lookup
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| 122 | */
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| 123 | if (!uvm_map_lookup_entry(ufi->map, ufi->orig_rvaddr,
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| 124 | &ufi->entry)) {
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| 125 | uvmfault_unlockmaps(ufi, write_lock); |
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| 126 | return(false); |
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| 127 | } |
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| 128 | |||
| 129 | /*
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| 130 | * reduce size if necessary
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| 131 | */
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| 132 | if (ufi->entry->end - ufi->orig_rvaddr < ufi->size)
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| 133 | ufi->size = ufi->entry->end - ufi->orig_rvaddr; |
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| 134 | |||
| 135 | /*
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| 136 | * submap? replace map with the submap and lookup again.
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| 137 | * note: VAs in submaps must match VAs in main map.
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| 138 | */
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| 139 | if (UVM_ET_ISSUBMAP(ufi->entry)) {
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| 140 | tmpmap = ufi->entry->object.sub_map; |
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| 141 | if (write_lock) {
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| 142 | vm_map_unlock(ufi->map); |
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| 143 | } else {
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| 144 | vm_map_unlock_read(ufi->map); |
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| 145 | } |
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| 146 | ufi->map = tmpmap; |
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| 147 | continue;
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| 148 | } |
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| 149 | |||
| 150 | /*
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| 151 | * got it!
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| 152 | */
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| 153 | |||
| 154 | ufi->mapv = ufi->map->timestamp; |
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| 155 | return(true); |
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| 156 | |||
| 157 | } /* while loop */
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| 158 | |||
| 159 | /*NOTREACHED*/
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| 160 | } |
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| 161 | |||
| 162 | /*
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| 163 | * uvmfault_relock: attempt to relock the same version of the map
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| 164 | *
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| 165 | * => fault data structures should be unlocked before calling.
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| 166 | * => if a success (true) maps will be locked after call.
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| 167 | */
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| 168 | |||
| 169 | static inline bool |
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| 170 | uvmfault_relock(struct uvm_faultinfo *ufi)
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| 171 | {
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| 172 | /*
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| 173 | * ufi can be NULL when this isn't really a fault,
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| 174 | * but merely paging in anon data.
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| 175 | */
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| 176 | |||
| 177 | if (ufi == NULL) { |
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| 178 | return true; |
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| 179 | } |
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| 180 | |||
| 181 | uvmexp.fltrelck++; |
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| 182 | |||
| 183 | /*
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| 184 | * relock map. fail if version mismatch (in which case nothing
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| 185 | * gets locked).
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| 186 | */
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| 187 | |||
| 188 | vm_map_lock_read(ufi->map); |
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| 189 | if (ufi->mapv != ufi->map->timestamp) {
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| 190 | vm_map_unlock_read(ufi->map); |
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| 191 | return(false); |
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| 192 | } |
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| 193 | |||
| 194 | uvmexp.fltrelckok++; |
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| 195 | return(true); |
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| 196 | } |
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| 197 | |||
| 198 | #endif /* _UVM_UVM_FAULT_I_H_ */ |