kern

annotate src/vm.c @ 57:437360696883

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I think we're done for now. two processes seem to be scheduled and switched just fine, fork seems to work (NO CoW YET!)
author John Tsiombikas <nuclear@member.fsf.org>
date Tue, 16 Aug 2011 03:26:53 +0300
parents 88a6c4e192f9
children c2692696f9ab
rev   line source
nuclear@17 1 #include <stdio.h>
nuclear@17 2 #include <string.h>
nuclear@17 3 #include <inttypes.h>
nuclear@52 4 #include <assert.h>
nuclear@52 5 #include "config.h"
nuclear@17 6 #include "vm.h"
nuclear@17 7 #include "intr.h"
nuclear@17 8 #include "mem.h"
nuclear@17 9 #include "panic.h"
nuclear@52 10 #include "proc.h"
nuclear@17 11
nuclear@17 12 #define IDMAP_START 0xa0000
nuclear@17 13
nuclear@24 14 #define PGDIR_ADDR 0xfffff000
nuclear@24 15 #define PGTBL_BASE (0xffffffff - 4096 * 1024 + 1)
nuclear@24 16 #define PGTBL(x) ((uint32_t*)(PGTBL_BASE + PGSIZE * (x)))
nuclear@24 17
nuclear@17 18 #define ATTR_PGDIR_MASK 0x3f
nuclear@17 19 #define ATTR_PGTBL_MASK 0x1ff
nuclear@17 20 #define ADDR_PGENT_MASK 0xfffff000
nuclear@17 21
nuclear@17 22 #define PAGEFAULT 14
nuclear@17 23
nuclear@22 24
nuclear@22 25 struct page_range {
nuclear@22 26 int start, end;
nuclear@22 27 struct page_range *next;
nuclear@22 28 };
nuclear@22 29
nuclear@22 30 /* defined in vm-asm.S */
nuclear@22 31 void enable_paging(void);
nuclear@23 32 void disable_paging(void);
nuclear@23 33 int get_paging_status(void);
nuclear@22 34 void set_pgdir_addr(uint32_t addr);
nuclear@23 35 void flush_tlb(void);
nuclear@23 36 void flush_tlb_addr(uint32_t addr);
nuclear@23 37 #define flush_tlb_page(p) flush_tlb_addr(PAGE_TO_ADDR(p))
nuclear@22 38 uint32_t get_fault_addr(void);
nuclear@22 39
nuclear@23 40 static void coalesce(struct page_range *low, struct page_range *mid, struct page_range *high);
nuclear@52 41 static void pgfault(int inum);
nuclear@22 42 static struct page_range *alloc_node(void);
nuclear@22 43 static void free_node(struct page_range *node);
nuclear@22 44
nuclear@22 45 /* page directory */
nuclear@22 46 static uint32_t *pgdir;
nuclear@22 47
nuclear@22 48 /* 2 lists of free ranges, for kernel memory and user memory */
nuclear@22 49 static struct page_range *pglist[2];
nuclear@22 50 /* list of free page_range structures to be used in the lists */
nuclear@22 51 static struct page_range *node_pool;
nuclear@23 52 /* the first page range for the whole kernel address space, to get things started */
nuclear@23 53 static struct page_range first_node;
nuclear@22 54
nuclear@22 55
nuclear@26 56 void init_vm(void)
nuclear@17 57 {
nuclear@19 58 uint32_t idmap_end;
nuclear@47 59 int i, kmem_start_pg, pgtbl_base_pg;
nuclear@19 60
nuclear@23 61 /* setup the page tables */
nuclear@18 62 pgdir = (uint32_t*)alloc_phys_page();
nuclear@23 63 memset(pgdir, 0, PGSIZE);
nuclear@24 64 set_pgdir_addr((uint32_t)pgdir);
nuclear@17 65
nuclear@17 66 /* map the video memory and kernel code 1-1 */
nuclear@19 67 get_kernel_mem_range(0, &idmap_end);
nuclear@19 68 map_mem_range(IDMAP_START, idmap_end - IDMAP_START, IDMAP_START, 0);
nuclear@17 69
nuclear@24 70 /* make the last page directory entry point to the page directory */
nuclear@24 71 pgdir[1023] = ((uint32_t)pgdir & ADDR_PGENT_MASK) | PG_PRESENT;
nuclear@24 72 pgdir = (uint32_t*)PGDIR_ADDR;
nuclear@24 73
nuclear@23 74 /* set the page fault handler */
nuclear@17 75 interrupt(PAGEFAULT, pgfault);
nuclear@17 76
nuclear@23 77 /* we can enable paging now */
nuclear@17 78 enable_paging();
nuclear@23 79
nuclear@23 80 /* initialize the virtual page allocator */
nuclear@23 81 node_pool = 0;
nuclear@23 82
nuclear@47 83 kmem_start_pg = ADDR_TO_PAGE(KMEM_START);
nuclear@47 84 pgtbl_base_pg = ADDR_TO_PAGE(PGTBL_BASE);
nuclear@47 85
nuclear@47 86 first_node.start = kmem_start_pg;
nuclear@47 87 first_node.end = pgtbl_base_pg;
nuclear@23 88 first_node.next = 0;
nuclear@23 89 pglist[MEM_KERNEL] = &first_node;
nuclear@23 90
nuclear@23 91 pglist[MEM_USER] = alloc_node();
nuclear@26 92 pglist[MEM_USER]->start = ADDR_TO_PAGE(idmap_end);
nuclear@47 93 pglist[MEM_USER]->end = kmem_start_pg;
nuclear@23 94 pglist[MEM_USER]->next = 0;
nuclear@47 95
nuclear@47 96 /* temporaroly map something into every 1024th page of the kernel address
nuclear@47 97 * space to force pre-allocation of all the kernel page-tables
nuclear@47 98 */
nuclear@47 99 for(i=kmem_start_pg; i<pgtbl_base_pg; i+=1024) {
nuclear@47 100 /* if there's already something mapped here, leave it alone */
nuclear@47 101 if(virt_to_phys_page(i) == -1) {
nuclear@47 102 map_page(i, 0, 0);
nuclear@47 103 unmap_page(i);
nuclear@47 104 }
nuclear@47 105 }
nuclear@17 106 }
nuclear@17 107
nuclear@23 108 /* if ppage == -1 we allocate a physical page by calling alloc_phys_page */
nuclear@23 109 int map_page(int vpage, int ppage, unsigned int attr)
nuclear@17 110 {
nuclear@17 111 uint32_t *pgtbl;
nuclear@25 112 int diridx, pgidx, pgon, intr_state;
nuclear@25 113
nuclear@25 114 intr_state = get_intr_state();
nuclear@25 115 disable_intr();
nuclear@23 116
nuclear@23 117 pgon = get_paging_status();
nuclear@23 118
nuclear@23 119 if(ppage < 0) {
nuclear@23 120 uint32_t addr = alloc_phys_page();
nuclear@23 121 if(!addr) {
nuclear@25 122 set_intr_state(intr_state);
nuclear@23 123 return -1;
nuclear@23 124 }
nuclear@23 125 ppage = ADDR_TO_PAGE(addr);
nuclear@23 126 }
nuclear@23 127
nuclear@23 128 diridx = PAGE_TO_PGTBL(vpage);
nuclear@23 129 pgidx = PAGE_TO_PGTBL_PG(vpage);
nuclear@17 130
nuclear@17 131 if(!(pgdir[diridx] & PG_PRESENT)) {
nuclear@55 132 /* no page table present, we must allocate one */
nuclear@17 133 uint32_t addr = alloc_phys_page();
nuclear@55 134
nuclear@55 135 /* make sure all page directory entries in the below the kernel vm
nuclear@55 136 * split have the user and writable bits set, otherwise further user
nuclear@55 137 * mappings on the same 4mb block will be unusable in user space.
nuclear@55 138 */
nuclear@55 139 unsigned int pgdir_attr = attr;
nuclear@55 140 if(vpage < ADDR_TO_PAGE(KMEM_START)) {
nuclear@55 141 pgdir_attr |= PG_USER | PG_WRITABLE;
nuclear@55 142 }
nuclear@55 143
nuclear@55 144 pgdir[diridx] = addr | (pgdir_attr & ATTR_PGDIR_MASK) | PG_PRESENT;
nuclear@24 145
nuclear@24 146 pgtbl = pgon ? PGTBL(diridx) : (uint32_t*)addr;
nuclear@18 147 memset(pgtbl, 0, PGSIZE);
nuclear@17 148 } else {
nuclear@24 149 if(pgon) {
nuclear@24 150 pgtbl = PGTBL(diridx);
nuclear@24 151 } else {
nuclear@24 152 pgtbl = (uint32_t*)(pgdir[diridx] & ADDR_PGENT_MASK);
nuclear@24 153 }
nuclear@17 154 }
nuclear@17 155
nuclear@17 156 pgtbl[pgidx] = PAGE_TO_ADDR(ppage) | (attr & ATTR_PGTBL_MASK) | PG_PRESENT;
nuclear@23 157 flush_tlb_page(vpage);
nuclear@23 158
nuclear@25 159 set_intr_state(intr_state);
nuclear@23 160 return 0;
nuclear@17 161 }
nuclear@17 162
nuclear@43 163 int unmap_page(int vpage)
nuclear@17 164 {
nuclear@17 165 uint32_t *pgtbl;
nuclear@43 166 int res = 0;
nuclear@17 167 int diridx = PAGE_TO_PGTBL(vpage);
nuclear@17 168 int pgidx = PAGE_TO_PGTBL_PG(vpage);
nuclear@17 169
nuclear@25 170 int intr_state = get_intr_state();
nuclear@25 171 disable_intr();
nuclear@25 172
nuclear@17 173 if(!(pgdir[diridx] & PG_PRESENT)) {
nuclear@17 174 goto err;
nuclear@17 175 }
nuclear@26 176 pgtbl = PGTBL(diridx);
nuclear@17 177
nuclear@17 178 if(!(pgtbl[pgidx] & PG_PRESENT)) {
nuclear@17 179 goto err;
nuclear@17 180 }
nuclear@17 181 pgtbl[pgidx] = 0;
nuclear@23 182 flush_tlb_page(vpage);
nuclear@17 183
nuclear@25 184 if(0) {
nuclear@17 185 err:
nuclear@25 186 printf("unmap_page(%d): page already not mapped\n", vpage);
nuclear@43 187 res = -1;
nuclear@25 188 }
nuclear@25 189 set_intr_state(intr_state);
nuclear@43 190 return res;
nuclear@17 191 }
nuclear@17 192
nuclear@22 193 /* if ppg_start is -1, we allocate physical pages to map with alloc_phys_page() */
nuclear@23 194 int map_page_range(int vpg_start, int pgcount, int ppg_start, unsigned int attr)
nuclear@17 195 {
nuclear@23 196 int i, phys_pg;
nuclear@17 197
nuclear@17 198 for(i=0; i<pgcount; i++) {
nuclear@26 199 phys_pg = ppg_start < 0 ? -1 : ppg_start + i;
nuclear@23 200 map_page(vpg_start + i, phys_pg, attr);
nuclear@17 201 }
nuclear@23 202 return 0;
nuclear@17 203 }
nuclear@17 204
nuclear@43 205 int unmap_page_range(int vpg_start, int pgcount)
nuclear@43 206 {
nuclear@43 207 int i, res = 0;
nuclear@43 208
nuclear@43 209 for(i=0; i<pgcount; i++) {
nuclear@43 210 if(unmap_page(vpg_start + i) == -1) {
nuclear@43 211 res = -1;
nuclear@43 212 }
nuclear@43 213 }
nuclear@43 214 return res;
nuclear@43 215 }
nuclear@43 216
nuclear@23 217 /* if paddr is 0, we allocate physical pages with alloc_phys_page() */
nuclear@23 218 int map_mem_range(uint32_t vaddr, size_t sz, uint32_t paddr, unsigned int attr)
nuclear@17 219 {
nuclear@17 220 int vpg_start, ppg_start, num_pages;
nuclear@17 221
nuclear@23 222 if(!sz) return -1;
nuclear@17 223
nuclear@17 224 if(ADDR_TO_PGOFFS(paddr)) {
nuclear@17 225 panic("map_mem_range called with unaligned physical address: %x\n", paddr);
nuclear@17 226 }
nuclear@17 227
nuclear@17 228 vpg_start = ADDR_TO_PAGE(vaddr);
nuclear@23 229 ppg_start = paddr > 0 ? ADDR_TO_PAGE(paddr) : -1;
nuclear@17 230 num_pages = ADDR_TO_PAGE(sz) + 1;
nuclear@17 231
nuclear@23 232 return map_page_range(vpg_start, num_pages, ppg_start, attr);
nuclear@17 233 }
nuclear@17 234
nuclear@18 235 uint32_t virt_to_phys(uint32_t vaddr)
nuclear@18 236 {
nuclear@43 237 int pg;
nuclear@43 238 uint32_t pgaddr;
nuclear@43 239
nuclear@43 240 if((pg = virt_to_phys_page(ADDR_TO_PAGE(vaddr))) == -1) {
nuclear@43 241 return 0;
nuclear@43 242 }
nuclear@43 243 pgaddr = PAGE_TO_ADDR(pg);
nuclear@43 244
nuclear@43 245 return pgaddr | ADDR_TO_PGOFFS(vaddr);
nuclear@43 246 }
nuclear@43 247
nuclear@43 248 int virt_to_phys_page(int vpg)
nuclear@43 249 {
nuclear@18 250 uint32_t pgaddr, *pgtbl;
nuclear@43 251 int diridx, pgidx;
nuclear@43 252
nuclear@43 253 if(vpg < 0 || vpg >= PAGE_COUNT) {
nuclear@43 254 return -1;
nuclear@43 255 }
nuclear@43 256
nuclear@43 257 diridx = PAGE_TO_PGTBL(vpg);
nuclear@43 258 pgidx = PAGE_TO_PGTBL_PG(vpg);
nuclear@18 259
nuclear@18 260 if(!(pgdir[diridx] & PG_PRESENT)) {
nuclear@43 261 return -1;
nuclear@18 262 }
nuclear@26 263 pgtbl = PGTBL(diridx);
nuclear@18 264
nuclear@18 265 if(!(pgtbl[pgidx] & PG_PRESENT)) {
nuclear@43 266 return -1;
nuclear@18 267 }
nuclear@18 268 pgaddr = pgtbl[pgidx] & PGENT_ADDR_MASK;
nuclear@43 269 return ADDR_TO_PAGE(pgaddr);
nuclear@18 270 }
nuclear@18 271
nuclear@22 272 /* allocate a contiguous block of virtual memory pages along with
nuclear@22 273 * backing physical memory for them, and update the page table.
nuclear@22 274 */
nuclear@22 275 int pgalloc(int num, int area)
nuclear@22 276 {
nuclear@25 277 int intr_state, ret = -1;
nuclear@22 278 struct page_range *node, *prev, dummy;
nuclear@22 279
nuclear@25 280 intr_state = get_intr_state();
nuclear@25 281 disable_intr();
nuclear@25 282
nuclear@22 283 dummy.next = pglist[area];
nuclear@22 284 node = pglist[area];
nuclear@22 285 prev = &dummy;
nuclear@22 286
nuclear@22 287 while(node) {
nuclear@22 288 if(node->end - node->start >= num) {
nuclear@22 289 ret = node->start;
nuclear@22 290 node->start += num;
nuclear@22 291
nuclear@22 292 if(node->start == node->end) {
nuclear@22 293 prev->next = node->next;
nuclear@22 294 node->next = 0;
nuclear@22 295
nuclear@22 296 if(node == pglist[area]) {
nuclear@22 297 pglist[area] = 0;
nuclear@22 298 }
nuclear@22 299 free_node(node);
nuclear@22 300 }
nuclear@22 301 break;
nuclear@22 302 }
nuclear@22 303
nuclear@22 304 prev = node;
nuclear@22 305 node = node->next;
nuclear@22 306 }
nuclear@22 307
nuclear@22 308 if(ret >= 0) {
nuclear@55 309 /*unsigned int attr = (area == MEM_USER) ? (PG_USER | PG_WRITABLE) : PG_GLOBAL;*/
nuclear@55 310 unsigned int attr = (area == MEM_USER) ? (PG_USER | PG_WRITABLE) : 0;
nuclear@55 311
nuclear@23 312 /* allocate physical storage and map */
nuclear@45 313 if(map_page_range(ret, num, -1, attr) == -1) {
nuclear@45 314 ret = -1;
nuclear@45 315 }
nuclear@45 316 }
nuclear@45 317
nuclear@45 318 set_intr_state(intr_state);
nuclear@45 319 return ret;
nuclear@45 320 }
nuclear@45 321
nuclear@45 322 int pgalloc_vrange(int start, int num)
nuclear@45 323 {
nuclear@45 324 struct page_range *node, *prev, dummy;
nuclear@45 325 int area, intr_state, ret = -1;
nuclear@45 326
nuclear@45 327 area = (start >= ADDR_TO_PAGE(KMEM_START)) ? MEM_KERNEL : MEM_USER;
nuclear@47 328 if(area == MEM_USER && start + num > ADDR_TO_PAGE(KMEM_START)) {
nuclear@45 329 printf("pgalloc_vrange: invalid range request crossing user/kernel split\n");
nuclear@45 330 return -1;
nuclear@45 331 }
nuclear@45 332
nuclear@45 333 intr_state = get_intr_state();
nuclear@45 334 disable_intr();
nuclear@45 335
nuclear@45 336 dummy.next = pglist[area];
nuclear@45 337 node = pglist[area];
nuclear@45 338 prev = &dummy;
nuclear@45 339
nuclear@45 340 /* check to see if the requested VM range is available */
nuclear@45 341 node = pglist[area];
nuclear@45 342 while(node) {
nuclear@45 343 if(start >= node->start && start + num <= node->end) {
nuclear@49 344 ret = start; /* can do .. */
nuclear@49 345
nuclear@49 346 if(start == node->start) {
nuclear@49 347 /* adjacent to the start of the range */
nuclear@49 348 node->start += num;
nuclear@49 349 } else if(start + num == node->end) {
nuclear@49 350 /* adjacent to the end of the range */
nuclear@49 351 node->end = start;
nuclear@49 352 } else {
nuclear@49 353 /* somewhere in the middle, which means we need
nuclear@49 354 * to allocate a new page_range
nuclear@49 355 */
nuclear@49 356 struct page_range *newnode;
nuclear@49 357
nuclear@49 358 if(!(newnode = alloc_node())) {
nuclear@49 359 panic("pgalloc_vrange failed to allocate new page_range while splitting a range in half... bummer\n");
nuclear@49 360 }
nuclear@49 361 newnode->start = start + num;
nuclear@49 362 newnode->end = node->end;
nuclear@49 363 newnode->next = node->next;
nuclear@49 364
nuclear@49 365 node->end = start;
nuclear@49 366 node->next = newnode;
nuclear@49 367 /* no need to check for null nodes at this point, there's
nuclear@49 368 * certainly stuff at the begining and the end, otherwise we
nuclear@49 369 * wouldn't be here. so break out of it.
nuclear@49 370 */
nuclear@49 371 break;
nuclear@49 372 }
nuclear@45 373
nuclear@45 374 if(node->start == node->end) {
nuclear@45 375 prev->next = node->next;
nuclear@45 376 node->next = 0;
nuclear@45 377
nuclear@45 378 if(node == pglist[area]) {
nuclear@45 379 pglist[area] = 0;
nuclear@45 380 }
nuclear@45 381 free_node(node);
nuclear@45 382 }
nuclear@45 383 break;
nuclear@45 384 }
nuclear@45 385
nuclear@45 386 prev = node;
nuclear@45 387 node = node->next;
nuclear@45 388 }
nuclear@45 389
nuclear@45 390 if(ret >= 0) {
nuclear@55 391 /*unsigned int attr = (area == MEM_USER) ? (PG_USER | PG_WRITABLE) : PG_GLOBAL;*/
nuclear@55 392 unsigned int attr = (area == MEM_USER) ? (PG_USER | PG_WRITABLE) : 0;
nuclear@55 393
nuclear@45 394 /* allocate physical storage and map */
nuclear@45 395 if(map_page_range(ret, num, -1, attr) == -1) {
nuclear@23 396 ret = -1;
nuclear@23 397 }
nuclear@22 398 }
nuclear@22 399
nuclear@25 400 set_intr_state(intr_state);
nuclear@22 401 return ret;
nuclear@22 402 }
nuclear@22 403
nuclear@22 404 void pgfree(int start, int num)
nuclear@22 405 {
nuclear@33 406 int i, area, intr_state;
nuclear@23 407 struct page_range *node, *new, *prev, *next;
nuclear@23 408
nuclear@25 409 intr_state = get_intr_state();
nuclear@25 410 disable_intr();
nuclear@25 411
nuclear@26 412 for(i=0; i<num; i++) {
nuclear@43 413 int phys_pg = virt_to_phys_page(start + i);
nuclear@43 414 if(phys_pg != -1) {
nuclear@43 415 free_phys_page(phys_pg);
nuclear@26 416 }
nuclear@26 417 }
nuclear@26 418
nuclear@23 419 if(!(new = alloc_node())) {
nuclear@23 420 panic("pgfree: can't allocate new page_range node to add the freed pages\n");
nuclear@23 421 }
nuclear@23 422 new->start = start;
nuclear@33 423 new->end = start + num;
nuclear@23 424
nuclear@23 425 area = PAGE_TO_ADDR(start) >= KMEM_START ? MEM_KERNEL : MEM_USER;
nuclear@23 426
nuclear@23 427 if(!pglist[area] || pglist[area]->start > start) {
nuclear@23 428 next = new->next = pglist[area];
nuclear@23 429 pglist[area] = new;
nuclear@23 430 prev = 0;
nuclear@23 431
nuclear@23 432 } else {
nuclear@23 433
nuclear@23 434 prev = 0;
nuclear@23 435 node = pglist[area];
nuclear@23 436 next = node ? node->next : 0;
nuclear@23 437
nuclear@23 438 while(node) {
nuclear@23 439 if(!next || next->start > start) {
nuclear@23 440 /* place here, after node */
nuclear@23 441 new->next = next;
nuclear@23 442 node->next = new;
nuclear@23 443 prev = node; /* needed by coalesce after the loop */
nuclear@23 444 break;
nuclear@23 445 }
nuclear@23 446
nuclear@23 447 prev = node;
nuclear@23 448 node = next;
nuclear@23 449 next = node ? node->next : 0;
nuclear@23 450 }
nuclear@23 451 }
nuclear@23 452
nuclear@23 453 coalesce(prev, new, next);
nuclear@25 454 set_intr_state(intr_state);
nuclear@23 455 }
nuclear@23 456
nuclear@23 457 static void coalesce(struct page_range *low, struct page_range *mid, struct page_range *high)
nuclear@23 458 {
nuclear@23 459 if(high) {
nuclear@23 460 if(mid->end == high->start) {
nuclear@23 461 mid->end = high->end;
nuclear@23 462 mid->next = high->next;
nuclear@23 463 free_node(high);
nuclear@23 464 }
nuclear@23 465 }
nuclear@23 466
nuclear@23 467 if(low) {
nuclear@23 468 if(low->end == mid->start) {
nuclear@23 469 low->end += mid->end;
nuclear@23 470 low->next = mid->next;
nuclear@23 471 free_node(mid);
nuclear@23 472 }
nuclear@23 473 }
nuclear@22 474 }
nuclear@22 475
nuclear@52 476 static void pgfault(int inum)
nuclear@17 477 {
nuclear@52 478 struct intr_frame *frm = get_intr_frame();
nuclear@52 479 uint32_t fault_addr = get_fault_addr();
nuclear@52 480
nuclear@52 481 /* the fault occured in user space */
nuclear@55 482 if(frm->err & PG_USER) {
nuclear@52 483 int fault_page = ADDR_TO_PAGE(fault_addr);
nuclear@52 484 struct process *proc = get_current_proc();
nuclear@55 485 printf("DBG: page fault in user space\n");
nuclear@52 486 assert(proc);
nuclear@52 487
nuclear@52 488 if(frm->err & PG_PRESENT) {
nuclear@52 489 /* it's not due to a missing page, just panic */
nuclear@52 490 goto unhandled;
nuclear@52 491 }
nuclear@52 492
nuclear@52 493 /* detect if it's an automatic stack growth deal */
nuclear@55 494 if(fault_page < proc->user_stack_pg && proc->user_stack_pg - fault_page < USTACK_MAXGROW) {
nuclear@55 495 int num_pages = proc->user_stack_pg - fault_page;
nuclear@52 496 printf("growing user (%d) stack by %d pages\n", proc->id, num_pages);
nuclear@52 497
nuclear@52 498 if(pgalloc_vrange(fault_page, num_pages) != fault_page) {
nuclear@52 499 printf("failed to allocate VM for stack growth\n");
nuclear@52 500 /* TODO: in the future we'd SIGSEGV the process here, for now just panic */
nuclear@52 501 goto unhandled;
nuclear@52 502 }
nuclear@55 503 proc->user_stack_pg = fault_page;
nuclear@52 504 return;
nuclear@52 505 }
nuclear@52 506 }
nuclear@52 507
nuclear@52 508 unhandled:
nuclear@17 509 printf("~~~~ PAGE FAULT ~~~~\n");
nuclear@52 510 printf("fault address: %x\n", fault_addr);
nuclear@17 511
nuclear@51 512 if(frm->err & PG_PRESENT) {
nuclear@51 513 if(frm->err & 8) {
nuclear@17 514 printf("reserved bit set in some paging structure\n");
nuclear@17 515 } else {
nuclear@55 516 printf("%s protection violation ", (frm->err & PG_WRITABLE) ? "WRITE" : "READ");
nuclear@55 517 printf("in %s mode\n", (frm->err & PG_USER) ? "user" : "kernel");
nuclear@17 518 }
nuclear@17 519 } else {
nuclear@17 520 printf("page not present\n");
nuclear@17 521 }
nuclear@19 522
nuclear@19 523 panic("unhandled page fault\n");
nuclear@17 524 }
nuclear@22 525
nuclear@22 526 /* --- page range list node management --- */
nuclear@23 527 #define NODES_IN_PAGE (PGSIZE / sizeof(struct page_range))
nuclear@23 528
nuclear@22 529 static struct page_range *alloc_node(void)
nuclear@22 530 {
nuclear@22 531 struct page_range *node;
nuclear@23 532 int pg, i;
nuclear@22 533
nuclear@22 534 if(node_pool) {
nuclear@22 535 node = node_pool;
nuclear@22 536 node_pool = node_pool->next;
nuclear@47 537 /*printf("alloc_node -> %x\n", (unsigned int)node);*/
nuclear@22 538 return node;
nuclear@22 539 }
nuclear@22 540
nuclear@23 541 /* no node structures in the pool, we need to allocate a new page,
nuclear@23 542 * split it up into node structures, add them in the pool, and
nuclear@23 543 * allocate one of them.
nuclear@22 544 */
nuclear@23 545 if(!(pg = pgalloc(1, MEM_KERNEL))) {
nuclear@22 546 panic("ran out of physical memory while allocating VM range structures\n");
nuclear@22 547 }
nuclear@23 548 node_pool = (struct page_range*)PAGE_TO_ADDR(pg);
nuclear@22 549
nuclear@23 550 /* link them up, skip the first as we'll just allocate it anyway */
nuclear@23 551 for(i=2; i<NODES_IN_PAGE; i++) {
nuclear@23 552 node_pool[i - 1].next = node_pool + i;
nuclear@23 553 }
nuclear@23 554 node_pool[NODES_IN_PAGE - 1].next = 0;
nuclear@23 555
nuclear@23 556 /* grab the first and return it */
nuclear@23 557 node = node_pool++;
nuclear@47 558 /*printf("alloc_node -> %x\n", (unsigned int)node);*/
nuclear@23 559 return node;
nuclear@22 560 }
nuclear@22 561
nuclear@22 562 static void free_node(struct page_range *node)
nuclear@22 563 {
nuclear@22 564 node->next = node_pool;
nuclear@22 565 node_pool = node;
nuclear@47 566 /*printf("free_node\n");*/
nuclear@22 567 }
nuclear@23 568
nuclear@47 569 /* clone_vm makes a copy of the current page tables, thus duplicating the
nuclear@47 570 * virtual address space.
nuclear@47 571 *
nuclear@47 572 * For the kernel part of the address space (last 256 page directory entries)
nuclear@47 573 * we don't want to diplicate the page tables, just point all page directory
nuclear@47 574 * entries to the same set of page tables.
nuclear@43 575 *
nuclear@57 576 * If "cow" is non-zero it also marks the shared user-space pages as
nuclear@57 577 * read-only, to implement copy-on-write.
nuclear@57 578 *
nuclear@43 579 * Returns the physical address of the new page directory.
nuclear@43 580 */
nuclear@57 581 uint32_t clone_vm(int cow)
nuclear@43 582 {
nuclear@57 583 int i, j, dirpg, tblpg, kstart_dirent;
nuclear@43 584 uint32_t paddr;
nuclear@43 585 uint32_t *ndir, *ntbl;
nuclear@43 586
nuclear@47 587 /* allocate the new page directory */
nuclear@43 588 if((dirpg = pgalloc(1, MEM_KERNEL)) == -1) {
nuclear@43 589 panic("clone_vmem: failed to allocate page directory page\n");
nuclear@43 590 }
nuclear@43 591 ndir = (uint32_t*)PAGE_TO_ADDR(dirpg);
nuclear@43 592
nuclear@47 593 /* allocate a virtual page for temporarily mapping all new
nuclear@47 594 * page tables while we populate them.
nuclear@47 595 */
nuclear@43 596 if((tblpg = pgalloc(1, MEM_KERNEL)) == -1) {
nuclear@43 597 panic("clone_vmem: failed to allocate page table page\n");
nuclear@43 598 }
nuclear@43 599 ntbl = (uint32_t*)PAGE_TO_ADDR(tblpg);
nuclear@43 600
nuclear@43 601 /* we will allocate physical pages and map them to this virtual page
nuclear@57 602 * as needed in the loop below. we don't need the physical page allocated
nuclear@57 603 * by pgalloc.
nuclear@43 604 */
nuclear@49 605 free_phys_page(virt_to_phys((uint32_t)ntbl));
nuclear@43 606
nuclear@48 607 kstart_dirent = ADDR_TO_PAGE(KMEM_START) / 1024;
nuclear@47 608
nuclear@47 609 /* user space */
nuclear@48 610 for(i=0; i<kstart_dirent; i++) {
nuclear@43 611 if(pgdir[i] & PG_PRESENT) {
nuclear@57 612 /* first go through all the entries of the existing
nuclear@57 613 * page table and unset the writable bits.
nuclear@57 614 */
nuclear@57 615 for(j=0; j<1024; j++) {
nuclear@57 616 PGTBL(i)[j] &= ~(uint32_t)PG_WRITABLE;
nuclear@57 617 }
nuclear@57 618
nuclear@57 619 /* allocate a page table for the clone */
nuclear@43 620 paddr = alloc_phys_page();
nuclear@43 621
nuclear@43 622 /* copy the page table */
nuclear@57 623 map_page(tblpg, ADDR_TO_PAGE(paddr), 0);
nuclear@43 624 memcpy(ntbl, PGTBL(i), PGSIZE);
nuclear@43 625
nuclear@43 626 /* set the new page directory entry */
nuclear@43 627 ndir[i] = paddr | (pgdir[i] & PGOFFS_MASK);
nuclear@43 628 } else {
nuclear@43 629 ndir[i] = 0;
nuclear@43 630 }
nuclear@43 631 }
nuclear@43 632
nuclear@55 633 /* for the kernel space we'll just use the same page tables */
nuclear@48 634 for(i=kstart_dirent; i<1024; i++) {
nuclear@49 635 ndir[i] = pgdir[i];
nuclear@47 636 }
nuclear@47 637
nuclear@57 638 /* we just changed all the page protection bits, so we need to flush the TLB */
nuclear@57 639 flush_tlb();
nuclear@57 640
nuclear@49 641 paddr = virt_to_phys((uint32_t)ndir);
nuclear@43 642
nuclear@57 643 /* unmap before freeing the virtual pages, to avoid deallocating the physical pages */
nuclear@43 644 unmap_page(dirpg);
nuclear@43 645 unmap_page(tblpg);
nuclear@43 646
nuclear@43 647 pgfree(dirpg, 1);
nuclear@43 648 pgfree(tblpg, 1);
nuclear@43 649
nuclear@43 650 return paddr;
nuclear@43 651 }
nuclear@57 652
nuclear@57 653 int get_page_bit(int pgnum, uint32_t bit, int wholepath)
nuclear@57 654 {
nuclear@57 655 int tidx = PAGE_TO_PGTBL(pgnum);
nuclear@57 656 int tent = PAGE_TO_PGTBL_PG(pgnum);
nuclear@57 657 uint32_t *pgtbl = PGTBL(tidx);
nuclear@57 658
nuclear@57 659 if(wholepath) {
nuclear@57 660 if((pgdir[tidx] & bit) == 0) {
nuclear@57 661 return 0;
nuclear@57 662 }
nuclear@57 663 }
nuclear@57 664
nuclear@57 665 return pgtbl[tent] & bit;
nuclear@57 666 }
nuclear@57 667
nuclear@57 668 void set_page_bit(int pgnum, uint32_t bit, int wholepath)
nuclear@57 669 {
nuclear@57 670 int tidx = PAGE_TO_PGTBL(pgnum);
nuclear@57 671 int tent = PAGE_TO_PGTBL_PG(pgnum);
nuclear@57 672 uint32_t *pgtbl = PGTBL(tidx);
nuclear@57 673
nuclear@57 674 if(wholepath) {
nuclear@57 675 pgdir[tidx] |= bit;
nuclear@57 676 }
nuclear@57 677 pgtbl[tent] |= bit;
nuclear@57 678
nuclear@57 679 flush_tlb_page(pgnum);
nuclear@57 680 }
nuclear@57 681
nuclear@57 682 void clear_page_bit(int pgnum, uint32_t bit, int wholepath)
nuclear@57 683 {
nuclear@57 684 int tidx = PAGE_TO_PGTBL(pgnum);
nuclear@57 685 int tent = PAGE_TO_PGTBL_PG(pgnum);
nuclear@57 686 uint32_t *pgtbl = PGTBL(tidx);
nuclear@57 687
nuclear@57 688 if(wholepath) {
nuclear@57 689 pgdir[tidx] &= ~bit;
nuclear@57 690 }
nuclear@57 691
nuclear@57 692 pgtbl[tent] &= ~bit;
nuclear@57 693
nuclear@57 694 flush_tlb_page(pgnum);
nuclear@57 695 }
nuclear@43 696
nuclear@43 697
nuclear@23 698 void dbg_print_vm(int area)
nuclear@23 699 {
nuclear@25 700 struct page_range *node;
nuclear@25 701 int last, intr_state;
nuclear@25 702
nuclear@25 703 intr_state = get_intr_state();
nuclear@25 704 disable_intr();
nuclear@25 705
nuclear@25 706 node = pglist[area];
nuclear@25 707 last = area == MEM_USER ? 0 : ADDR_TO_PAGE(KMEM_START);
nuclear@23 708
nuclear@23 709 printf("%s vm space\n", area == MEM_USER ? "user" : "kernel");
nuclear@23 710
nuclear@23 711 while(node) {
nuclear@23 712 if(node->start > last) {
nuclear@23 713 printf(" vm-used: %x -> %x\n", PAGE_TO_ADDR(last), PAGE_TO_ADDR(node->start));
nuclear@23 714 }
nuclear@23 715
nuclear@23 716 printf(" vm-free: %x -> ", PAGE_TO_ADDR(node->start));
nuclear@23 717 if(node->end >= PAGE_COUNT) {
nuclear@23 718 printf("END\n");
nuclear@23 719 } else {
nuclear@23 720 printf("%x\n", PAGE_TO_ADDR(node->end));
nuclear@23 721 }
nuclear@23 722
nuclear@23 723 last = node->end;
nuclear@23 724 node = node->next;
nuclear@23 725 }
nuclear@25 726
nuclear@25 727 set_intr_state(intr_state);
nuclear@23 728 }