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57 | 57 | ||
58 | #define KAS_START_INDEX PTL0_INDEX(KERNEL_ADDRESS_SPACE_START) |
58 | #define KAS_START_INDEX PTL0_INDEX(KERNEL_ADDRESS_SPACE_START) |
59 | #define KAS_END_INDEX PTL0_INDEX(KERNEL_ADDRESS_SPACE_END) |
59 | #define KAS_END_INDEX PTL0_INDEX(KERNEL_ADDRESS_SPACE_END) |
60 | #define KAS_INDICES (1+(KAS_END_INDEX-KAS_START_INDEX)) |
60 | #define KAS_INDICES (1+(KAS_END_INDEX-KAS_START_INDEX)) |
61 | 61 | ||
62 | /* |
- | |
63 | * Here we assume that PFN (Physical Frame Number) space |
- | |
64 | * is smaller than the width of index_t. UNALLOCATED_PFN |
- | |
65 | * can be then used to mark mappings wich were not |
- | |
66 | * yet allocated a physical frame. |
- | |
67 | */ |
- | |
68 | #define UNALLOCATED_PFN ((index_t) -1) |
62 | static int get_area_flags(as_area_t *a); |
69 | 63 | ||
70 | /** Create address space. */ |
64 | /** Create address space. */ |
71 | /* |
65 | /* |
72 | * FIXME: this interface must be meaningful for all possible VAT |
66 | * FIXME: this interface must be meaningful for all possible VAT |
73 | * (Virtual Address Translation) mechanisms. |
67 | * (Virtual Address Translation) mechanisms. |
Line 131... | Line 125... | ||
131 | /* |
125 | /* |
132 | * TODO: test as_area which is to be created doesn't overlap with an existing one. |
126 | * TODO: test as_area which is to be created doesn't overlap with an existing one. |
133 | */ |
127 | */ |
134 | 128 | ||
135 | a = (as_area_t *) malloc(sizeof(as_area_t)); |
129 | a = (as_area_t *) malloc(sizeof(as_area_t)); |
136 | if (a) { |
130 | if (a) { |
137 | int i; |
- | |
138 | - | ||
139 | a->mapping = (index_t *) malloc(size * sizeof(index_t)); |
- | |
140 | if (!a->mapping) { |
- | |
141 | free(a); |
- | |
142 | spinlock_unlock(&as->lock); |
- | |
143 | interrupts_restore(ipl); |
- | |
144 | return NULL; |
- | |
145 | } |
- | |
146 | - | ||
147 | for (i=0; i<size; i++) { |
- | |
148 | /* |
- | |
149 | * Frames will be allocated on-demand by |
- | |
150 | * as_page_fault() or preloaded by |
- | |
151 | * as_area_set_mapping(). |
- | |
152 | */ |
- | |
153 | a->mapping[i] = UNALLOCATED_PFN; |
- | |
154 | } |
- | |
155 | - | ||
156 | spinlock_initialize(&a->lock, "as_area_lock"); |
131 | spinlock_initialize(&a->lock, "as_area_lock"); |
157 | 132 | ||
158 | link_initialize(&a->link); |
133 | link_initialize(&a->link); |
159 | a->type = type; |
134 | a->type = type; |
160 | a->size = size; |
135 | a->size = size; |
161 | a->base = base; |
136 | a->base = base; |
162 | 137 | ||
163 | list_append(&a->link, &as->as_area_head); |
138 | list_append(&a->link, &as->as_area_head); |
164 | - | ||
165 | } |
139 | } |
166 | 140 | ||
167 | spinlock_unlock(&as->lock); |
141 | spinlock_unlock(&as->lock); |
168 | interrupts_restore(ipl); |
142 | interrupts_restore(ipl); |
169 | 143 | ||
170 | return a; |
144 | return a; |
171 | } |
145 | } |
172 | 146 | ||
173 | /** Load mapping for address space area. |
147 | /** Initialize mapping for one page of address space. |
174 | * |
148 | * |
- | 149 | * This functions maps 'page' to 'frame' according |
|
- | 150 | * to attributes of the address space area to |
|
175 | * Initialize a->mapping. |
151 | * wich 'page' belongs. |
176 | * |
152 | * |
177 | * @param a Target address space area. |
153 | * @param a Target address space. |
178 | * @param vpn Page number relative to area start. |
154 | * @param page Virtual page within the area. |
179 | * @param pfn Frame number to map. |
155 | * @param frame Physical frame to which page will be mapped. |
180 | */ |
156 | */ |
181 | void as_area_set_mapping(as_area_t *a, index_t vpn, index_t pfn) |
157 | void as_set_mapping(as_t *as, __address page, __address frame) |
182 | { |
158 | { |
183 | ASSERT(vpn < a->size); |
159 | as_area_t *a, *area = NULL; |
184 | ASSERT(a->mapping[vpn] == UNALLOCATED_PFN); |
- | |
185 | ASSERT(pfn != UNALLOCATED_PFN); |
160 | link_t *cur; |
186 | - | ||
187 | ipl_t ipl; |
161 | ipl_t ipl; |
188 | 162 | ||
189 | ipl = interrupts_disable(); |
163 | ipl = interrupts_disable(); |
190 | spinlock_lock(&a->lock); |
164 | spinlock_lock(&as->lock); |
- | 165 | ||
- | 166 | /* |
|
- | 167 | * First, try locate an area. |
|
- | 168 | */ |
|
- | 169 | for (cur = as->as_area_head.next; cur != &as->as_area_head; cur = cur->next) { |
|
- | 170 | a = list_get_instance(cur, as_area_t, link); |
|
- | 171 | spinlock_lock(&a->lock); |
|
- | 172 | ||
- | 173 | if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) { |
|
- | 174 | area = a; |
|
- | 175 | break; |
|
- | 176 | } |
|
- | 177 | ||
- | 178 | spinlock_unlock(&a->lock); |
|
- | 179 | } |
|
- | 180 | ||
- | 181 | if (!area) { |
|
- | 182 | panic("page not part of any as_area\n"); |
|
- | 183 | } |
|
- | 184 | ||
- | 185 | /* |
|
- | 186 | * Note: area->lock is held. |
|
- | 187 | */ |
|
191 | 188 | ||
192 | a->mapping[vpn] = pfn; |
189 | page_mapping_insert(page, as->asid, frame, get_area_flags(area), (__address) as->ptl0); |
193 | 190 | ||
- | 191 | spinlock_unlock(&area->lock); |
|
194 | spinlock_unlock(&a->lock); |
192 | spinlock_unlock(&as->lock); |
195 | interrupts_restore(ipl); |
193 | interrupts_restore(ipl); |
196 | } |
194 | } |
197 | 195 | ||
198 | /** Handle page fault within the current address space. |
196 | /** Handle page fault within the current address space. |
199 | * |
197 | * |
Line 204... | Line 202... | ||
204 | * |
202 | * |
205 | * @return 0 on page fault, 1 on success. |
203 | * @return 0 on page fault, 1 on success. |
206 | */ |
204 | */ |
207 | int as_page_fault(__address page) |
205 | int as_page_fault(__address page) |
208 | { |
206 | { |
209 | int flags; |
- | |
210 | link_t *cur; |
207 | link_t *cur; |
211 | as_area_t *a, *area = NULL; |
208 | as_area_t *a, *area = NULL; |
212 | index_t vpn; |
- | |
213 | __address frame; |
209 | __address frame; |
214 | 210 | ||
215 | ASSERT(AS); |
211 | ASSERT(AS); |
216 | spinlock_lock(&AS->lock); |
212 | spinlock_lock(&AS->lock); |
217 | 213 | ||
Line 226... | Line 222... | ||
226 | 222 | ||
227 | /* |
223 | /* |
228 | * We found the area containing 'page'. |
224 | * We found the area containing 'page'. |
229 | * TODO: access checking |
225 | * TODO: access checking |
230 | */ |
226 | */ |
231 | - | ||
232 | vpn = (page - a->base) / PAGE_SIZE; |
- | |
233 | area = a; |
227 | area = a; |
234 | break; |
228 | break; |
235 | } |
229 | } |
236 | 230 | ||
237 | spinlock_unlock(&a->lock); |
231 | spinlock_unlock(&a->lock); |
Line 249... | Line 243... | ||
249 | /* |
243 | /* |
250 | * Note: area->lock is held. |
244 | * Note: area->lock is held. |
251 | */ |
245 | */ |
252 | 246 | ||
253 | /* |
247 | /* |
- | 248 | * In general, there can be several reasons that |
|
- | 249 | * can have caused this fault. |
|
- | 250 | * |
|
- | 251 | * - non-existent mapping: the area is a scratch |
|
254 | * Decide if a frame needs to be allocated. |
252 | * area (e.g. stack) and so far has not been |
255 | * If so, allocate it and adjust area->mapping map. |
253 | * allocated a frame for the faulting page |
- | 254 | * |
|
- | 255 | * - non-present mapping: another possibility, |
|
- | 256 | * currently not implemented, would be frame |
|
- | 257 | * reuse; when this becomes a possibility, |
|
- | 258 | * do not forget to distinguish between |
|
- | 259 | * the different causes |
|
256 | */ |
260 | */ |
257 | if (area->mapping[vpn] == UNALLOCATED_PFN) { |
- | |
258 | frame = frame_alloc(0, ONE_FRAME, NULL); |
261 | frame = frame_alloc(0, ONE_FRAME, NULL); |
259 | memsetb(PA2KA(frame), FRAME_SIZE, 0); |
262 | memsetb(PA2KA(frame), FRAME_SIZE, 0); |
260 | area->mapping[vpn] = frame / FRAME_SIZE; |
- | |
261 | ASSERT(area->mapping[vpn] != UNALLOCATED_PFN); |
- | |
262 | } else |
- | |
263 | frame = area->mapping[vpn] * FRAME_SIZE; |
- | |
264 | 263 | ||
265 | switch (area->type) { |
- | |
266 | case AS_AREA_TEXT: |
- | |
267 | flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE; |
- | |
268 | break; |
- | |
269 | case AS_AREA_DATA: |
- | |
270 | case AS_AREA_STACK: |
- | |
271 | flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE; |
- | |
272 | break; |
- | |
273 | default: |
- | |
274 | panic("unexpected as_area_type_t %d", area->type); |
- | |
275 | } |
- | |
276 | - | ||
277 | /* |
264 | /* |
278 | * Map 'page' to 'frame'. |
265 | * Map 'page' to 'frame'. |
279 | * Note that TLB shootdown is not attempted as only new information is being |
266 | * Note that TLB shootdown is not attempted as only new information is being |
280 | * inserted into page tables. |
267 | * inserted into page tables. |
281 | */ |
268 | */ |
282 | page_mapping_insert(page, AS->asid, frame, flags, (__address) AS->ptl0); |
269 | page_mapping_insert(page, AS->asid, frame, get_area_flags(area), (__address) AS->ptl0); |
283 | 270 | ||
284 | spinlock_unlock(&area->lock); |
271 | spinlock_unlock(&area->lock); |
285 | spinlock_unlock(&AS->lock); |
272 | spinlock_unlock(&AS->lock); |
286 | 273 | ||
287 | return 1; |
274 | return 1; |
Line 310... | Line 297... | ||
310 | */ |
297 | */ |
311 | as_install_arch(as); |
298 | as_install_arch(as); |
312 | 299 | ||
313 | AS = as; |
300 | AS = as; |
314 | } |
301 | } |
- | 302 | ||
- | 303 | /** Compute flags for virtual address translation subsytem. |
|
- | 304 | * |
|
- | 305 | * The address space area must be locked. |
|
- | 306 | * Interrupts must be disabled. |
|
- | 307 | * |
|
- | 308 | * @param a Address space area. |
|
- | 309 | * |
|
- | 310 | * @return Flags to be used in page_mapping_insert(). |
|
- | 311 | */ |
|
- | 312 | int get_area_flags(as_area_t *a) |
|
- | 313 | { |
|
- | 314 | int flags; |
|
- | 315 | ||
- | 316 | switch (a->type) { |
|
- | 317 | case AS_AREA_TEXT: |
|
- | 318 | flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE; |
|
- | 319 | break; |
|
- | 320 | case AS_AREA_DATA: |
|
- | 321 | case AS_AREA_STACK: |
|
- | 322 | flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE; |
|
- | 323 | break; |
|
- | 324 | default: |
|
- | 325 | panic("unexpected as_area_type_t %d", a->type); |
|
- | 326 | } |
|
- | 327 | ||
- | 328 | return flags; |
|
- | 329 | } |