Changes in kernel/generic/src/mm/as.c [ac9e79d:6785b88b] in mainline
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kernel/generic/src/mm/as.c (modified) (19 diffs)
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kernel/generic/src/mm/as.c
rac9e79d r6785b88b 1 1 /* 2 2 * Copyright (c) 2010 Jakub Jermar 3 * Copyright (c) 2018 Jiri Svoboda 3 4 * All rights reserved. 4 5 * … … 111 112 as_t *AS_KERNEL = NULL; 112 113 114 static void *as_areas_getkey(odlink_t *); 115 static int as_areas_cmp(void *, void *); 116 113 117 NO_TRACE static errno_t as_constructor(void *obj, unsigned int flags) 114 118 { … … 137 141 if (!AS_KERNEL) 138 142 panic("Cannot create kernel address space."); 143 144 /* 145 * Make sure the kernel address space 146 * reference count never drops to zero. 147 */ 148 as_hold(AS_KERNEL); 139 149 } 140 150 … … 150 160 (void) as_create_arch(as, 0); 151 161 152 btree_create(&as->as_area_btree);162 odict_initialize(&as->as_areas, as_areas_getkey, as_areas_cmp); 153 163 154 164 if (flags & FLAG_AS_KERNEL) … … 224 234 /* 225 235 * Destroy address space areas of the address space. 226 * The B+tree must be walked carefully because it is 227 * also being destroyed. 228 */ 229 bool cond = true; 230 while (cond) { 231 assert(!list_empty(&as->as_area_btree.leaf_list)); 232 233 btree_node_t *node = 234 list_get_instance(list_first(&as->as_area_btree.leaf_list), 235 btree_node_t, leaf_link); 236 237 if ((cond = node->keys)) 238 as_area_destroy(as, node->key[0]); 239 } 240 241 btree_destroy(&as->as_area_btree); 236 * Need to start from the beginning each time since we are destroying 237 * the areas. 238 */ 239 as_area_t *area = as_area_first(as); 240 while (area != NULL) { 241 /* 242 * XXX We already have as_area_t, but as_area_destroy will 243 * have to search for it. This could be made faster. 244 */ 245 as_area_destroy(as, area->base); 246 area = as_area_first(as); 247 } 248 249 odict_finalize(&as->as_areas); 242 250 243 251 #ifdef AS_PAGE_TABLE … … 277 285 } 278 286 287 /** Return first address space area. 288 * 289 * @param as Address space 290 * @return First area in @a as (i.e. area with the lowest base address) 291 * or @c NULL if there is none 292 */ 293 as_area_t *as_area_first(as_t *as) 294 { 295 odlink_t *odlink = odict_first(&as->as_areas); 296 if (odlink == NULL) 297 return NULL; 298 299 return odict_get_instance(odlink, as_area_t, las_areas); 300 } 301 302 /** Return next address space area. 303 * 304 * @param cur Current area 305 * @return Next area in the same address space or @c NULL if @a cur is the 306 * last area. 307 */ 308 as_area_t *as_area_next(as_area_t *cur) 309 { 310 odlink_t *odlink = odict_next(&cur->las_areas, &cur->as->as_areas); 311 if (odlink == NULL) 312 return NULL; 313 314 return odict_get_instance(odlink, as_area_t, las_areas); 315 } 316 317 /** Determine if area with specified parameters would conflict with 318 * a specific existing address space area. 319 * 320 * @param addr Starting virtual address of the area being tested. 321 * @param count Number of pages in the area being tested. 322 * @param guarded True if the area being tested is protected by guard pages. 323 * @param area Area against which we are testing. 324 * 325 * @return True if the two areas conflict, false otherwise. 326 */ 327 NO_TRACE static bool area_is_conflicting(uintptr_t addr, 328 size_t count, bool guarded, as_area_t *area) 329 { 330 assert((addr % PAGE_SIZE) == 0); 331 332 size_t gsize = P2SZ(count); 333 size_t agsize = P2SZ(area->pages); 334 335 /* 336 * A guarded area has one guard page before, one page after. 337 * What we do here is: if either area is guarded, we add 338 * PAGE_SIZE to the size of both areas. That guarantees 339 * they will be spaced at least one page apart. 340 */ 341 if (guarded || (area->flags & AS_AREA_GUARD) != 0) { 342 /* Add guard page size unless area is at the end of VA domain */ 343 if (!overflows(addr, P2SZ(count))) 344 gsize += PAGE_SIZE; 345 346 /* Add guard page size unless area is at the end of VA domain */ 347 if (!overflows(area->base, P2SZ(area->pages))) 348 agsize += PAGE_SIZE; 349 } 350 351 return overlaps(addr, gsize, area->base, agsize); 352 353 } 354 279 355 /** Check area conflicts with other areas. 280 356 * … … 283 359 * @param count Number of pages in the area being tested. 284 360 * @param guarded True if the area being tested is protected by guard pages. 285 * @param avoid Do not touch this area. 361 * @param avoid Do not touch this area. I.e. this area is not considered 362 * as presenting a conflict. 286 363 * 287 364 * @return True if there is no conflict, false otherwise. … … 308 385 309 386 /* 310 * The leaf node is found in O(log n), where n is proportional to 311 * the number of address space areas belonging to as. 312 * The check for conflicts is then attempted on the rightmost 313 * record in the left neighbour, the leftmost record in the right 314 * neighbour and all records in the leaf node itself. 315 */ 316 btree_node_t *leaf; 317 as_area_t *area = 318 (as_area_t *) btree_search(&as->as_area_btree, addr, &leaf); 319 if (area) { 320 if (area != avoid) 321 return false; 322 } 323 324 /* First, check the two border cases. */ 325 btree_node_t *node = 326 btree_leaf_node_left_neighbour(&as->as_area_btree, leaf); 327 if (node) { 328 area = (as_area_t *) node->value[node->keys - 1]; 387 * To determine if we overlap with another area, we just need 388 * to look at overlap with the last area with base address <= 389 * to ours and on the first area with base address > than ours. 390 * 391 * First find last area with <= base address. 392 */ 393 odlink_t *odlink = odict_find_leq(&as->as_areas, &addr, NULL); 394 if (odlink != NULL) { 395 as_area_t *area = odict_get_instance(odlink, as_area_t, 396 las_areas); 329 397 330 398 if (area != avoid) { 331 399 mutex_lock(&area->lock); 332 333 /* 334 * If at least one of the two areas are protected 335 * by the AS_AREA_GUARD flag then we must be sure 336 * that they are separated by at least one unmapped 337 * page. 338 */ 339 int const gp = (guarded || 340 (area->flags & AS_AREA_GUARD)) ? 1 : 0; 341 342 /* 343 * The area comes from the left neighbour node, which 344 * means that there already are some areas in the leaf 345 * node, which in turn means that adding gp is safe and 346 * will not cause an integer overflow. 347 */ 348 if (overlaps(addr, P2SZ(count), area->base, 349 P2SZ(area->pages + gp))) { 400 if (area_is_conflicting(addr, count, guarded, area)) { 350 401 mutex_unlock(&area->lock); 351 402 return false; … … 354 405 mutex_unlock(&area->lock); 355 406 } 356 } 357 358 node = btree_leaf_node_right_neighbour(&as->as_area_btree, leaf); 359 if (node) { 360 area = (as_area_t *) node->value[0]; 407 408 /* Next area */ 409 odlink = odict_next(odlink, &as->as_areas); 410 } 411 412 /* 413 * Next area, if any, is the first with base > than our base address. 414 * If there was no area with <= base, we need to look at the first area. 415 */ 416 if (odlink == NULL) 417 odlink = odict_first(&as->as_areas); 418 419 if (odlink != NULL) { 420 as_area_t *area = odict_get_instance(odlink, as_area_t, 421 las_areas); 361 422 362 423 if (area != avoid) { 363 int gp;364 365 424 mutex_lock(&area->lock); 366 367 gp = (guarded || (area->flags & AS_AREA_GUARD)) ? 1 : 0; 368 if (gp && overflows(addr, P2SZ(count))) { 369 /* 370 * Guard page not needed if the supposed area 371 * is adjacent to the end of the address space. 372 * We already know that the following test is 373 * going to fail... 374 */ 375 gp--; 376 } 377 378 if (overlaps(addr, P2SZ(count + gp), area->base, 379 P2SZ(area->pages))) { 425 if (area_is_conflicting(addr, count, guarded, area)) { 380 426 mutex_unlock(&area->lock); 381 427 return false; … … 384 430 mutex_unlock(&area->lock); 385 431 } 386 }387 388 /* Second, check the leaf node. */389 btree_key_t i;390 for (i = 0; i < leaf->keys; i++) {391 area = (as_area_t *) leaf->value[i];392 int agp;393 int gp;394 395 if (area == avoid)396 continue;397 398 mutex_lock(&area->lock);399 400 gp = (guarded || (area->flags & AS_AREA_GUARD)) ? 1 : 0;401 agp = gp;402 403 /*404 * Sanitize the two possible unsigned integer overflows.405 */406 if (gp && overflows(addr, P2SZ(count)))407 gp--;408 if (agp && overflows(area->base, P2SZ(area->pages)))409 agp--;410 411 if (overlaps(addr, P2SZ(count + gp), area->base,412 P2SZ(area->pages + agp))) {413 mutex_unlock(&area->lock);414 return false;415 }416 417 mutex_unlock(&area->lock);418 432 } 419 433 … … 482 496 483 497 /* Eventually check the addresses behind each area */ 484 list_foreach(as->as_area_btree.leaf_list, leaf_link, btree_node_t, node) { 485 486 for (btree_key_t i = 0; i < node->keys; i++) { 487 as_area_t *area = (as_area_t *) node->value[i]; 488 489 mutex_lock(&area->lock); 490 491 addr = 492 ALIGN_UP(area->base + P2SZ(area->pages), PAGE_SIZE); 493 494 if (guarded || area->flags & AS_AREA_GUARD) { 495 /* 496 * We must leave an unmapped page 497 * between the two areas. 498 */ 499 addr += P2SZ(1); 500 } 501 502 bool avail = 503 ((addr >= bound) && (addr >= area->base) && 504 (check_area_conflicts(as, addr, pages, guarded, area))); 505 506 mutex_unlock(&area->lock); 507 508 if (avail) 509 return addr; 510 } 498 as_area_t *area = as_area_first(as); 499 while (area != NULL) { 500 mutex_lock(&area->lock); 501 502 addr = area->base + P2SZ(area->pages); 503 504 if (guarded || area->flags & AS_AREA_GUARD) { 505 /* 506 * We must leave an unmapped page 507 * between the two areas. 508 */ 509 addr += P2SZ(1); 510 } 511 512 bool avail = 513 ((addr >= bound) && (addr >= area->base) && 514 (check_area_conflicts(as, addr, pages, guarded, area))); 515 516 mutex_unlock(&area->lock); 517 518 if (avail) 519 return addr; 520 521 area = as_area_next(area); 511 522 } 512 523 … … 623 634 624 635 area->as = as; 636 odlink_initialize(&area->las_areas); 625 637 area->flags = flags; 626 638 area->attributes = attrs; … … 680 692 681 693 btree_create(&area->used_space); 682 btree_insert(&as->as_area_btree, *base, (void *) area, 683 NULL); 694 odict_insert(&area->las_areas, &as->as_areas, NULL); 684 695 685 696 mutex_unlock(&as->lock); … … 701 712 assert(mutex_locked(&as->lock)); 702 713 703 btree_node_t *leaf; 704 as_area_t *area = (as_area_t *) btree_search(&as->as_area_btree, va, 705 &leaf); 706 if (area) { 707 /* va is the base address of an address space area */ 708 mutex_lock(&area->lock); 714 odlink_t *odlink = odict_find_leq(&as->as_areas, &va, NULL); 715 if (odlink == NULL) 716 return NULL; 717 718 as_area_t *area = odict_get_instance(odlink, as_area_t, las_areas); 719 mutex_lock(&area->lock); 720 721 assert(area->base <= va); 722 723 if (va <= area->base + (P2SZ(area->pages) - 1)) 709 724 return area; 710 } 711 712 /* 713 * Search the leaf node and the rightmost record of its left neighbour 714 * to find out whether this is a miss or va belongs to an address 715 * space area found there. 716 */ 717 718 /* First, search the leaf node itself. */ 719 btree_key_t i; 720 721 for (i = 0; i < leaf->keys; i++) { 722 area = (as_area_t *) leaf->value[i]; 723 724 mutex_lock(&area->lock); 725 726 if ((area->base <= va) && 727 (va <= area->base + (P2SZ(area->pages) - 1))) 728 return area; 729 730 mutex_unlock(&area->lock); 731 } 732 733 /* 734 * Second, locate the left neighbour and test its last record. 735 * Because of its position in the B+tree, it must have base < va. 736 */ 737 btree_node_t *lnode = btree_leaf_node_left_neighbour(&as->as_area_btree, 738 leaf); 739 if (lnode) { 740 area = (as_area_t *) lnode->value[lnode->keys - 1]; 741 742 mutex_lock(&area->lock); 743 744 if (va <= area->base + (P2SZ(area->pages) - 1)) 745 return area; 746 747 mutex_unlock(&area->lock); 748 } 749 725 726 mutex_unlock(&area->lock); 750 727 return NULL; 751 728 } … … 985 962 area->backend->destroy(area); 986 963 987 uintptr_t base = area->base;988 989 964 page_table_lock(as, false); 990 965 … … 1053 1028 * Remove the empty area from address space. 1054 1029 */ 1055 btree_remove(&as->as_area_btree, base, NULL);1030 odict_remove(&area->las_areas); 1056 1031 1057 1032 free(area); … … 1608 1583 1609 1584 return area_flags_to_page_flags(area->flags); 1585 } 1586 1587 /** Get key function for the @c as_t.as_areas ordered dictionary. 1588 * 1589 * @param odlink Link 1590 * @return Pointer to task ID cast as 'void *' 1591 */ 1592 static void *as_areas_getkey(odlink_t *odlink) 1593 { 1594 as_area_t *area = odict_get_instance(odlink, as_area_t, las_areas); 1595 return (void *) &area->base; 1596 } 1597 1598 /** Key comparison function for the @c as_t.as_areas ordered dictionary. 1599 * 1600 * @param a Pointer to area A base 1601 * @param b Pointer to area B base 1602 * @return -1, 0, 1 iff base of A is lower than, equal to, higher than B 1603 */ 1604 static int as_areas_cmp(void *a, void *b) 1605 { 1606 uintptr_t base_a = *(uintptr_t *)a; 1607 uintptr_t base_b = *(uintptr_t *)b; 1608 1609 if (base_a < base_b) 1610 return -1; 1611 else if (base_a == base_b) 1612 return 0; 1613 else 1614 return +1; 1610 1615 } 1611 1616 … … 2242 2247 mutex_lock(&as->lock); 2243 2248 2244 /* First pass, count number of areas. */ 2245 2246 size_t area_cnt = 0; 2247 2248 list_foreach(as->as_area_btree.leaf_list, leaf_link, btree_node_t, 2249 node) { 2250 area_cnt += node->keys; 2251 } 2249 /* Count number of areas. */ 2250 size_t area_cnt = odict_count(&as->as_areas); 2252 2251 2253 2252 size_t isize = area_cnt * sizeof(as_area_info_t); 2254 2253 as_area_info_t *info = nfmalloc(isize); 2255 2254 2256 /* Second pass, recorddata. */2255 /* Record area data. */ 2257 2256 2258 2257 size_t area_idx = 0; 2259 2258 2260 list_foreach(as->as_area_btree.leaf_list, leaf_link, btree_node_t, 2261 node) { 2262 btree_key_t i; 2263 2264 for (i = 0; i < node->keys; i++) { 2265 as_area_t *area = node->value[i]; 2266 2267 assert(area_idx < area_cnt); 2268 mutex_lock(&area->lock); 2269 2270 info[area_idx].start_addr = area->base; 2271 info[area_idx].size = P2SZ(area->pages); 2272 info[area_idx].flags = area->flags; 2273 ++area_idx; 2274 2275 mutex_unlock(&area->lock); 2276 } 2259 as_area_t *area = as_area_first(as); 2260 while (area != NULL) { 2261 assert(area_idx < area_cnt); 2262 mutex_lock(&area->lock); 2263 2264 info[area_idx].start_addr = area->base; 2265 info[area_idx].size = P2SZ(area->pages); 2266 info[area_idx].flags = area->flags; 2267 ++area_idx; 2268 2269 mutex_unlock(&area->lock); 2270 area = as_area_next(area); 2277 2271 } 2278 2272 … … 2293 2287 2294 2288 /* Print out info about address space areas */ 2295 list_foreach(as->as_area_btree.leaf_list, leaf_link, btree_node_t, 2296 node) { 2297 btree_key_t i; 2298 2299 for (i = 0; i < node->keys; i++) { 2300 as_area_t *area = node->value[i]; 2301 2302 mutex_lock(&area->lock); 2303 printf("as_area: %p, base=%p, pages=%zu" 2304 " (%p - %p)\n", area, (void *) area->base, 2305 area->pages, (void *) area->base, 2306 (void *) (area->base + P2SZ(area->pages))); 2307 mutex_unlock(&area->lock); 2308 } 2289 as_area_t *area = as_area_first(as); 2290 while (area != NULL) { 2291 mutex_lock(&area->lock); 2292 printf("as_area: %p, base=%p, pages=%zu" 2293 " (%p - %p)\n", area, (void *) area->base, 2294 area->pages, (void *) area->base, 2295 (void *) (area->base + P2SZ(area->pages))); 2296 mutex_unlock(&area->lock); 2297 2298 area = as_area_next(area); 2309 2299 } 2310 2300
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