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703 | jermar | 1 | /* |
2 | * Copyright (C) 2001-2006 Jakub Jermar |
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3 | * All rights reserved. |
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4 | * |
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5 | * Redistribution and use in source and binary forms, with or without |
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6 | * modification, are permitted provided that the following conditions |
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7 | * are met: |
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8 | * |
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9 | * - Redistributions of source code must retain the above copyright |
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10 | * notice, this list of conditions and the following disclaimer. |
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11 | * - Redistributions in binary form must reproduce the above copyright |
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12 | * notice, this list of conditions and the following disclaimer in the |
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13 | * documentation and/or other materials provided with the distribution. |
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14 | * - The name of the author may not be used to endorse or promote products |
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15 | * derived from this software without specific prior written permission. |
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16 | * |
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17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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27 | */ |
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28 | |||
29 | /* |
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30 | * This file contains address space manipulation functions. |
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31 | * Roughly speaking, this is a higher-level client of |
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32 | * Virtual Address Translation (VAT) subsystem. |
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33 | */ |
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34 | |||
35 | #include <mm/as.h> |
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756 | jermar | 36 | #include <arch/mm/as.h> |
703 | jermar | 37 | #include <mm/page.h> |
38 | #include <mm/frame.h> |
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814 | palkovsky | 39 | #include <mm/slab.h> |
703 | jermar | 40 | #include <mm/tlb.h> |
41 | #include <arch/mm/page.h> |
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42 | #include <genarch/mm/page_pt.h> |
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1108 | jermar | 43 | #include <genarch/mm/page_ht.h> |
727 | jermar | 44 | #include <mm/asid.h> |
703 | jermar | 45 | #include <arch/mm/asid.h> |
46 | #include <arch/types.h> |
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47 | #include <typedefs.h> |
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48 | #include <synch/spinlock.h> |
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49 | #include <config.h> |
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788 | jermar | 50 | #include <adt/list.h> |
1147 | jermar | 51 | #include <adt/btree.h> |
703 | jermar | 52 | #include <panic.h> |
53 | #include <arch/asm.h> |
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54 | #include <debug.h> |
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55 | #include <memstr.h> |
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1070 | jermar | 56 | #include <macros.h> |
703 | jermar | 57 | #include <arch.h> |
58 | #include <print.h> |
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59 | |||
756 | jermar | 60 | as_operations_t *as_operations = NULL; |
703 | jermar | 61 | |
823 | jermar | 62 | /** Address space lock. It protects inactive_as_with_asid_head. */ |
63 | SPINLOCK_INITIALIZE(as_lock); |
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64 | |||
65 | /** |
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66 | * This list contains address spaces that are not active on any |
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67 | * processor and that have valid ASID. |
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68 | */ |
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69 | LIST_INITIALIZE(inactive_as_with_asid_head); |
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70 | |||
757 | jermar | 71 | /** Kernel address space. */ |
72 | as_t *AS_KERNEL = NULL; |
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73 | |||
754 | jermar | 74 | static int get_area_flags(as_area_t *a); |
977 | jermar | 75 | static as_area_t *find_area_and_lock(as_t *as, __address va); |
1048 | jermar | 76 | static bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area); |
703 | jermar | 77 | |
756 | jermar | 78 | /** Initialize address space subsystem. */ |
79 | void as_init(void) |
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80 | { |
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81 | as_arch_init(); |
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789 | palkovsky | 82 | AS_KERNEL = as_create(FLAG_AS_KERNEL); |
756 | jermar | 83 | if (!AS_KERNEL) |
84 | panic("can't create kernel address space\n"); |
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85 | } |
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86 | |||
757 | jermar | 87 | /** Create address space. |
88 | * |
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89 | * @param flags Flags that influence way in wich the address space is created. |
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90 | */ |
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756 | jermar | 91 | as_t *as_create(int flags) |
703 | jermar | 92 | { |
93 | as_t *as; |
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94 | |||
822 | palkovsky | 95 | as = (as_t *) malloc(sizeof(as_t), 0); |
823 | jermar | 96 | link_initialize(&as->inactive_as_with_asid_link); |
822 | palkovsky | 97 | spinlock_initialize(&as->lock, "as_lock"); |
1147 | jermar | 98 | btree_create(&as->as_area_btree); |
822 | palkovsky | 99 | |
100 | if (flags & FLAG_AS_KERNEL) |
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101 | as->asid = ASID_KERNEL; |
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102 | else |
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103 | as->asid = ASID_INVALID; |
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104 | |||
823 | jermar | 105 | as->refcount = 0; |
822 | palkovsky | 106 | as->page_table = page_table_create(flags); |
703 | jermar | 107 | |
108 | return as; |
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109 | } |
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110 | |||
973 | palkovsky | 111 | /** Free Adress space */ |
112 | void as_free(as_t *as) |
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113 | { |
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114 | ASSERT(as->refcount == 0); |
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115 | |||
116 | /* TODO: free as_areas and other resources held by as */ |
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117 | /* TODO: free page table */ |
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118 | free(as); |
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119 | } |
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120 | |||
703 | jermar | 121 | /** Create address space area of common attributes. |
122 | * |
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123 | * The created address space area is added to the target address space. |
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124 | * |
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125 | * @param as Target address space. |
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1026 | jermar | 126 | * @param flags Flags of the area. |
1048 | jermar | 127 | * @param size Size of area. |
703 | jermar | 128 | * @param base Base address of area. |
129 | * |
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130 | * @return Address space area on success or NULL on failure. |
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131 | */ |
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1026 | jermar | 132 | as_area_t *as_area_create(as_t *as, int flags, size_t size, __address base) |
703 | jermar | 133 | { |
134 | ipl_t ipl; |
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135 | as_area_t *a; |
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136 | |||
137 | if (base % PAGE_SIZE) |
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1048 | jermar | 138 | return NULL; |
139 | |||
1233 | jermar | 140 | if (!size) |
141 | return NULL; |
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142 | |||
1048 | jermar | 143 | /* Writeable executable areas are not supported. */ |
144 | if ((flags & AS_AREA_EXEC) && (flags & AS_AREA_WRITE)) |
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145 | return NULL; |
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703 | jermar | 146 | |
147 | ipl = interrupts_disable(); |
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148 | spinlock_lock(&as->lock); |
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149 | |||
1048 | jermar | 150 | if (!check_area_conflicts(as, base, size, NULL)) { |
151 | spinlock_unlock(&as->lock); |
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152 | interrupts_restore(ipl); |
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153 | return NULL; |
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154 | } |
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703 | jermar | 155 | |
822 | palkovsky | 156 | a = (as_area_t *) malloc(sizeof(as_area_t), 0); |
703 | jermar | 157 | |
822 | palkovsky | 158 | spinlock_initialize(&a->lock, "as_area_lock"); |
159 | |||
1026 | jermar | 160 | a->flags = flags; |
1048 | jermar | 161 | a->pages = SIZE2FRAMES(size); |
822 | palkovsky | 162 | a->base = base; |
163 | |||
1147 | jermar | 164 | btree_insert(&as->as_area_btree, base, (void *) a, NULL); |
822 | palkovsky | 165 | |
703 | jermar | 166 | spinlock_unlock(&as->lock); |
167 | interrupts_restore(ipl); |
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704 | jermar | 168 | |
703 | jermar | 169 | return a; |
170 | } |
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171 | |||
754 | jermar | 172 | /** Initialize mapping for one page of address space. |
703 | jermar | 173 | * |
754 | jermar | 174 | * This functions maps 'page' to 'frame' according |
175 | * to attributes of the address space area to |
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176 | * wich 'page' belongs. |
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703 | jermar | 177 | * |
840 | jermar | 178 | * @param as Target address space. |
754 | jermar | 179 | * @param page Virtual page within the area. |
180 | * @param frame Physical frame to which page will be mapped. |
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703 | jermar | 181 | */ |
754 | jermar | 182 | void as_set_mapping(as_t *as, __address page, __address frame) |
703 | jermar | 183 | { |
977 | jermar | 184 | as_area_t *area; |
703 | jermar | 185 | ipl_t ipl; |
186 | |||
187 | ipl = interrupts_disable(); |
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1044 | jermar | 188 | page_table_lock(as, true); |
703 | jermar | 189 | |
977 | jermar | 190 | area = find_area_and_lock(as, page); |
754 | jermar | 191 | if (!area) { |
192 | panic("page not part of any as_area\n"); |
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193 | } |
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194 | |||
756 | jermar | 195 | page_mapping_insert(as, page, frame, get_area_flags(area)); |
754 | jermar | 196 | |
197 | spinlock_unlock(&area->lock); |
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1044 | jermar | 198 | page_table_unlock(as, true); |
703 | jermar | 199 | interrupts_restore(ipl); |
200 | } |
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201 | |||
202 | /** Handle page fault within the current address space. |
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203 | * |
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204 | * This is the high-level page fault handler. |
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205 | * Interrupts are assumed disabled. |
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206 | * |
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207 | * @param page Faulting page. |
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208 | * |
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704 | jermar | 209 | * @return 0 on page fault, 1 on success. |
703 | jermar | 210 | */ |
211 | int as_page_fault(__address page) |
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212 | { |
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1044 | jermar | 213 | pte_t *pte; |
977 | jermar | 214 | as_area_t *area; |
703 | jermar | 215 | __address frame; |
216 | |||
217 | ASSERT(AS); |
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1044 | jermar | 218 | |
703 | jermar | 219 | spinlock_lock(&AS->lock); |
977 | jermar | 220 | area = find_area_and_lock(AS, page); |
703 | jermar | 221 | if (!area) { |
222 | /* |
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223 | * No area contained mapping for 'page'. |
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224 | * Signal page fault to low-level handler. |
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225 | */ |
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226 | spinlock_unlock(&AS->lock); |
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227 | return 0; |
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228 | } |
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229 | |||
1179 | jermar | 230 | ASSERT(!(area->flags & AS_AREA_DEVICE)); |
231 | |||
1044 | jermar | 232 | page_table_lock(AS, false); |
233 | |||
703 | jermar | 234 | /* |
1044 | jermar | 235 | * To avoid race condition between two page faults |
236 | * on the same address, we need to make sure |
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237 | * the mapping has not been already inserted. |
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238 | */ |
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239 | if ((pte = page_mapping_find(AS, page))) { |
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240 | if (PTE_PRESENT(pte)) { |
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241 | page_table_unlock(AS, false); |
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242 | spinlock_unlock(&area->lock); |
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243 | spinlock_unlock(&AS->lock); |
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244 | return 1; |
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245 | } |
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246 | } |
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247 | |||
248 | /* |
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754 | jermar | 249 | * In general, there can be several reasons that |
250 | * can have caused this fault. |
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251 | * |
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252 | * - non-existent mapping: the area is a scratch |
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253 | * area (e.g. stack) and so far has not been |
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254 | * allocated a frame for the faulting page |
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255 | * |
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256 | * - non-present mapping: another possibility, |
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257 | * currently not implemented, would be frame |
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258 | * reuse; when this becomes a possibility, |
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259 | * do not forget to distinguish between |
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260 | * the different causes |
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703 | jermar | 261 | */ |
814 | palkovsky | 262 | frame = PFN2ADDR(frame_alloc(ONE_FRAME, 0)); |
754 | jermar | 263 | memsetb(PA2KA(frame), FRAME_SIZE, 0); |
703 | jermar | 264 | |
265 | /* |
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266 | * Map 'page' to 'frame'. |
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267 | * Note that TLB shootdown is not attempted as only new information is being |
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268 | * inserted into page tables. |
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269 | */ |
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756 | jermar | 270 | page_mapping_insert(AS, page, frame, get_area_flags(area)); |
1044 | jermar | 271 | page_table_unlock(AS, false); |
703 | jermar | 272 | |
273 | spinlock_unlock(&area->lock); |
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274 | spinlock_unlock(&AS->lock); |
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275 | return 1; |
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276 | } |
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277 | |||
823 | jermar | 278 | /** Switch address spaces. |
703 | jermar | 279 | * |
823 | jermar | 280 | * @param old Old address space or NULL. |
281 | * @param new New address space. |
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703 | jermar | 282 | */ |
823 | jermar | 283 | void as_switch(as_t *old, as_t *new) |
703 | jermar | 284 | { |
285 | ipl_t ipl; |
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823 | jermar | 286 | bool needs_asid = false; |
703 | jermar | 287 | |
288 | ipl = interrupts_disable(); |
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823 | jermar | 289 | spinlock_lock(&as_lock); |
703 | jermar | 290 | |
291 | /* |
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823 | jermar | 292 | * First, take care of the old address space. |
293 | */ |
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294 | if (old) { |
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295 | spinlock_lock(&old->lock); |
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296 | ASSERT(old->refcount); |
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297 | if((--old->refcount == 0) && (old != AS_KERNEL)) { |
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298 | /* |
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299 | * The old address space is no longer active on |
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300 | * any processor. It can be appended to the |
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301 | * list of inactive address spaces with assigned |
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302 | * ASID. |
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303 | */ |
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304 | ASSERT(old->asid != ASID_INVALID); |
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305 | list_append(&old->inactive_as_with_asid_link, &inactive_as_with_asid_head); |
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306 | } |
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307 | spinlock_unlock(&old->lock); |
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308 | } |
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309 | |||
310 | /* |
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311 | * Second, prepare the new address space. |
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312 | */ |
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313 | spinlock_lock(&new->lock); |
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314 | if ((new->refcount++ == 0) && (new != AS_KERNEL)) { |
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315 | if (new->asid != ASID_INVALID) |
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316 | list_remove(&new->inactive_as_with_asid_link); |
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317 | else |
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318 | needs_asid = true; /* defer call to asid_get() until new->lock is released */ |
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319 | } |
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320 | SET_PTL0_ADDRESS(new->page_table); |
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321 | spinlock_unlock(&new->lock); |
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322 | |||
323 | if (needs_asid) { |
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324 | /* |
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325 | * Allocation of new ASID was deferred |
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326 | * until now in order to avoid deadlock. |
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327 | */ |
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328 | asid_t asid; |
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329 | |||
330 | asid = asid_get(); |
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331 | spinlock_lock(&new->lock); |
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332 | new->asid = asid; |
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333 | spinlock_unlock(&new->lock); |
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334 | } |
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335 | spinlock_unlock(&as_lock); |
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336 | interrupts_restore(ipl); |
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337 | |||
338 | /* |
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703 | jermar | 339 | * Perform architecture-specific steps. |
727 | jermar | 340 | * (e.g. write ASID to hardware register etc.) |
703 | jermar | 341 | */ |
823 | jermar | 342 | as_install_arch(new); |
703 | jermar | 343 | |
823 | jermar | 344 | AS = new; |
703 | jermar | 345 | } |
754 | jermar | 346 | |
347 | /** Compute flags for virtual address translation subsytem. |
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348 | * |
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349 | * The address space area must be locked. |
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350 | * Interrupts must be disabled. |
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351 | * |
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352 | * @param a Address space area. |
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353 | * |
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354 | * @return Flags to be used in page_mapping_insert(). |
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355 | */ |
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356 | int get_area_flags(as_area_t *a) |
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357 | { |
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358 | int flags; |
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359 | |||
1178 | jermar | 360 | flags = PAGE_USER | PAGE_PRESENT; |
754 | jermar | 361 | |
1026 | jermar | 362 | if (a->flags & AS_AREA_READ) |
363 | flags |= PAGE_READ; |
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364 | |||
365 | if (a->flags & AS_AREA_WRITE) |
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366 | flags |= PAGE_WRITE; |
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367 | |||
368 | if (a->flags & AS_AREA_EXEC) |
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369 | flags |= PAGE_EXEC; |
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370 | |||
1178 | jermar | 371 | if (!(a->flags & AS_AREA_DEVICE)) |
372 | flags |= PAGE_CACHEABLE; |
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373 | |||
754 | jermar | 374 | return flags; |
375 | } |
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756 | jermar | 376 | |
377 | /** Create page table. |
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378 | * |
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379 | * Depending on architecture, create either address space |
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380 | * private or global page table. |
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381 | * |
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382 | * @param flags Flags saying whether the page table is for kernel address space. |
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383 | * |
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384 | * @return First entry of the page table. |
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385 | */ |
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386 | pte_t *page_table_create(int flags) |
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387 | { |
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388 | ASSERT(as_operations); |
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389 | ASSERT(as_operations->page_table_create); |
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390 | |||
391 | return as_operations->page_table_create(flags); |
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392 | } |
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977 | jermar | 393 | |
1044 | jermar | 394 | /** Lock page table. |
395 | * |
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396 | * This function should be called before any page_mapping_insert(), |
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397 | * page_mapping_remove() and page_mapping_find(). |
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398 | * |
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399 | * Locking order is such that address space areas must be locked |
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400 | * prior to this call. Address space can be locked prior to this |
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401 | * call in which case the lock argument is false. |
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402 | * |
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403 | * @param as Address space. |
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404 | * @param as_locked If false, do not attempt to lock as->lock. |
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405 | */ |
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406 | void page_table_lock(as_t *as, bool lock) |
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407 | { |
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408 | ASSERT(as_operations); |
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409 | ASSERT(as_operations->page_table_lock); |
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410 | |||
411 | as_operations->page_table_lock(as, lock); |
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412 | } |
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413 | |||
414 | /** Unlock page table. |
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415 | * |
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416 | * @param as Address space. |
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417 | * @param as_locked If false, do not attempt to unlock as->lock. |
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418 | */ |
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419 | void page_table_unlock(as_t *as, bool unlock) |
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420 | { |
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421 | ASSERT(as_operations); |
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422 | ASSERT(as_operations->page_table_unlock); |
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423 | |||
424 | as_operations->page_table_unlock(as, unlock); |
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425 | } |
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426 | |||
977 | jermar | 427 | /** Find address space area and change it. |
428 | * |
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429 | * @param as Address space. |
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430 | * @param address Virtual address belonging to the area to be changed. Must be page-aligned. |
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431 | * @param size New size of the virtual memory block starting at address. |
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432 | * @param flags Flags influencing the remap operation. Currently unused. |
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433 | * |
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434 | * @return address on success, (__address) -1 otherwise. |
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435 | */ |
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1227 | jermar | 436 | __address as_area_resize(as_t *as, __address address, size_t size, int flags) |
977 | jermar | 437 | { |
438 | as_area_t *area = NULL; |
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439 | ipl_t ipl; |
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440 | size_t pages; |
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441 | |||
442 | ipl = interrupts_disable(); |
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443 | spinlock_lock(&as->lock); |
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444 | |||
445 | /* |
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446 | * Locate the area. |
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447 | */ |
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448 | area = find_area_and_lock(as, address); |
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449 | if (!area) { |
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450 | spinlock_unlock(&as->lock); |
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1048 | jermar | 451 | interrupts_restore(ipl); |
977 | jermar | 452 | return (__address) -1; |
453 | } |
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454 | |||
1179 | jermar | 455 | if (area->flags & AS_AREA_DEVICE) { |
456 | /* |
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457 | * Remapping of address space areas associated |
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458 | * with memory mapped devices is not supported. |
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459 | */ |
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460 | spinlock_unlock(&area->lock); |
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461 | spinlock_unlock(&as->lock); |
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462 | interrupts_restore(ipl); |
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463 | return (__address) -1; |
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464 | } |
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465 | |||
977 | jermar | 466 | pages = SIZE2FRAMES((address - area->base) + size); |
1233 | jermar | 467 | if (!pages) { |
468 | /* |
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469 | * Zero size address space areas are not allowed. |
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470 | */ |
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471 | spinlock_unlock(&area->lock); |
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472 | spinlock_unlock(&as->lock); |
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473 | interrupts_restore(ipl); |
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474 | return (__address) -1; |
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475 | } |
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476 | |||
1048 | jermar | 477 | if (pages < area->pages) { |
977 | jermar | 478 | int i; |
479 | |||
480 | /* |
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481 | * Shrinking the area. |
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1147 | jermar | 482 | * No need to check for overlaps. |
977 | jermar | 483 | */ |
1048 | jermar | 484 | for (i = pages; i < area->pages; i++) { |
977 | jermar | 485 | pte_t *pte; |
486 | |||
487 | /* |
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488 | * Releasing physical memory. |
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489 | * This depends on the fact that the memory was allocated using frame_alloc(). |
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1044 | jermar | 490 | */ |
491 | page_table_lock(as, false); |
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977 | jermar | 492 | pte = page_mapping_find(as, area->base + i*PAGE_SIZE); |
980 | palkovsky | 493 | if (pte && PTE_VALID(pte)) { |
1044 | jermar | 494 | __address frame; |
495 | |||
977 | jermar | 496 | ASSERT(PTE_PRESENT(pte)); |
1044 | jermar | 497 | frame = PTE_GET_FRAME(pte); |
983 | palkovsky | 498 | page_mapping_remove(as, area->base + i*PAGE_SIZE); |
1044 | jermar | 499 | page_table_unlock(as, false); |
500 | |||
501 | frame_free(ADDR2PFN(frame)); |
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502 | } else { |
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503 | page_table_unlock(as, false); |
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977 | jermar | 504 | } |
505 | } |
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506 | /* |
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507 | * Invalidate TLB's. |
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508 | */ |
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1048 | jermar | 509 | tlb_shootdown_start(TLB_INVL_PAGES, AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages); |
510 | tlb_invalidate_pages(AS->asid, area->base + pages*PAGE_SIZE, area->pages - pages); |
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977 | jermar | 511 | tlb_shootdown_finalize(); |
1147 | jermar | 512 | } else { |
513 | /* |
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514 | * Growing the area. |
||
515 | * Check for overlaps with other address space areas. |
||
516 | */ |
||
517 | if (!check_area_conflicts(as, address, pages * PAGE_SIZE, area)) { |
||
518 | spinlock_unlock(&area->lock); |
||
519 | spinlock_unlock(&as->lock); |
||
520 | interrupts_restore(ipl); |
||
521 | return (__address) -1; |
||
522 | } |
||
983 | palkovsky | 523 | } |
524 | |||
1048 | jermar | 525 | area->pages = pages; |
977 | jermar | 526 | |
527 | spinlock_unlock(&area->lock); |
||
528 | spinlock_unlock(&as->lock); |
||
529 | interrupts_restore(ipl); |
||
530 | |||
531 | return address; |
||
532 | } |
||
533 | |||
534 | /** Find address space area and lock it. |
||
535 | * |
||
536 | * The address space must be locked and interrupts must be disabled. |
||
537 | * |
||
538 | * @param as Address space. |
||
539 | * @param va Virtual address. |
||
540 | * |
||
541 | * @return Locked address space area containing va on success or NULL on failure. |
||
542 | */ |
||
543 | as_area_t *find_area_and_lock(as_t *as, __address va) |
||
544 | { |
||
545 | as_area_t *a; |
||
1147 | jermar | 546 | btree_node_t *leaf, *lnode; |
547 | int i; |
||
977 | jermar | 548 | |
1147 | jermar | 549 | a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf); |
550 | if (a) { |
||
551 | /* va is the base address of an address space area */ |
||
977 | jermar | 552 | spinlock_lock(&a->lock); |
1147 | jermar | 553 | return a; |
554 | } |
||
555 | |||
556 | /* |
||
1150 | jermar | 557 | * Search the leaf node and the righmost record of its left neighbour |
1147 | jermar | 558 | * to find out whether this is a miss or va belongs to an address |
559 | * space area found there. |
||
560 | */ |
||
561 | |||
562 | /* First, search the leaf node itself. */ |
||
563 | for (i = 0; i < leaf->keys; i++) { |
||
564 | a = (as_area_t *) leaf->value[i]; |
||
565 | spinlock_lock(&a->lock); |
||
566 | if ((a->base <= va) && (va < a->base + a->pages * PAGE_SIZE)) { |
||
567 | return a; |
||
568 | } |
||
569 | spinlock_unlock(&a->lock); |
||
570 | } |
||
977 | jermar | 571 | |
1147 | jermar | 572 | /* |
1150 | jermar | 573 | * Second, locate the left neighbour and test its last record. |
1148 | jermar | 574 | * Because of its position in the B+tree, it must have base < va. |
1147 | jermar | 575 | */ |
1150 | jermar | 576 | if ((lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) { |
1147 | jermar | 577 | a = (as_area_t *) lnode->value[lnode->keys - 1]; |
578 | spinlock_lock(&a->lock); |
||
579 | if (va < a->base + a->pages * PAGE_SIZE) { |
||
1048 | jermar | 580 | return a; |
1147 | jermar | 581 | } |
977 | jermar | 582 | spinlock_unlock(&a->lock); |
583 | } |
||
584 | |||
585 | return NULL; |
||
586 | } |
||
1048 | jermar | 587 | |
588 | /** Check area conflicts with other areas. |
||
589 | * |
||
590 | * The address space must be locked and interrupts must be disabled. |
||
591 | * |
||
592 | * @param as Address space. |
||
593 | * @param va Starting virtual address of the area being tested. |
||
594 | * @param size Size of the area being tested. |
||
595 | * @param avoid_area Do not touch this area. |
||
596 | * |
||
597 | * @return True if there is no conflict, false otherwise. |
||
598 | */ |
||
599 | bool check_area_conflicts(as_t *as, __address va, size_t size, as_area_t *avoid_area) |
||
600 | { |
||
601 | as_area_t *a; |
||
1147 | jermar | 602 | btree_node_t *leaf, *node; |
603 | int i; |
||
1048 | jermar | 604 | |
1070 | jermar | 605 | /* |
606 | * We don't want any area to have conflicts with NULL page. |
||
607 | */ |
||
608 | if (overlaps(va, size, NULL, PAGE_SIZE)) |
||
609 | return false; |
||
610 | |||
1147 | jermar | 611 | /* |
612 | * The leaf node is found in O(log n), where n is proportional to |
||
613 | * the number of address space areas belonging to as. |
||
614 | * The check for conflicts is then attempted on the rightmost |
||
1150 | jermar | 615 | * record in the left neighbour, the leftmost record in the right |
616 | * neighbour and all records in the leaf node itself. |
||
1147 | jermar | 617 | */ |
1048 | jermar | 618 | |
1147 | jermar | 619 | if ((a = (as_area_t *) btree_search(&as->as_area_btree, va, &leaf))) { |
620 | if (a != avoid_area) |
||
621 | return false; |
||
622 | } |
||
623 | |||
624 | /* First, check the two border cases. */ |
||
1150 | jermar | 625 | if ((node = btree_leaf_node_left_neighbour(&as->as_area_btree, leaf))) { |
1147 | jermar | 626 | a = (as_area_t *) node->value[node->keys - 1]; |
627 | spinlock_lock(&a->lock); |
||
628 | if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) { |
||
629 | spinlock_unlock(&a->lock); |
||
630 | return false; |
||
631 | } |
||
632 | spinlock_unlock(&a->lock); |
||
633 | } |
||
1150 | jermar | 634 | if ((node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf))) { |
1147 | jermar | 635 | a = (as_area_t *) node->value[0]; |
636 | spinlock_lock(&a->lock); |
||
637 | if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) { |
||
638 | spinlock_unlock(&a->lock); |
||
639 | return false; |
||
640 | } |
||
641 | spinlock_unlock(&a->lock); |
||
642 | } |
||
643 | |||
644 | /* Second, check the leaf node. */ |
||
645 | for (i = 0; i < leaf->keys; i++) { |
||
646 | a = (as_area_t *) leaf->value[i]; |
||
647 | |||
1048 | jermar | 648 | if (a == avoid_area) |
649 | continue; |
||
1147 | jermar | 650 | |
1048 | jermar | 651 | spinlock_lock(&a->lock); |
1147 | jermar | 652 | if (overlaps(va, size, a->base, a->pages * PAGE_SIZE)) { |
653 | spinlock_unlock(&a->lock); |
||
654 | return false; |
||
655 | } |
||
1048 | jermar | 656 | spinlock_unlock(&a->lock); |
657 | } |
||
658 | |||
1070 | jermar | 659 | /* |
660 | * So far, the area does not conflict with other areas. |
||
661 | * Check if it doesn't conflict with kernel address space. |
||
662 | */ |
||
663 | if (!KERNEL_ADDRESS_SPACE_SHADOWED) { |
||
664 | return !overlaps(va, size, |
||
665 | KERNEL_ADDRESS_SPACE_START, KERNEL_ADDRESS_SPACE_END-KERNEL_ADDRESS_SPACE_START); |
||
666 | } |
||
667 | |||
1048 | jermar | 668 | return true; |
669 | } |