1 /* 2 * linux/mm/memory.c 3 * 4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds 5 */ 6 7 /* 8 * demand-loading started 01.12.91 - seems it is high on the list of 9 * things wanted, and it should be easy to implement. - Linus 10 */ 11 12 /* 13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared 14 * pages started 02.12.91, seems to work. - Linus. 15 * 16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it 17 * would have taken more than the 6M I have free, but it worked well as 18 * far as I could see. 19 * 20 * Also corrected some "invalidate()"s - I wasn't doing enough of them. 21 */ 22 23 /* 24 * Real VM (paging to/from disk) started 18.12.91. Much more work and 25 * thought has to go into this. Oh, well.. 26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. 27 * Found it. Everything seems to work now. 28 * 20.12.91 - Ok, making the swap-device changeable like the root. 29 */ 30 31 /* 32 * 05.04.94 - Multi-page memory management added for v1.1. 33 * Idea by Alex Bligh (alex@cconcepts.co.uk) 34 * 35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG 36 * (Gerhard.Wichert@pdb.siemens.de) 37 * 38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) 39 */ 40 41 #include <linux/kernel_stat.h> 42 #include <linux/mm.h> 43 #include <linux/hugetlb.h> 44 #include <linux/mman.h> 45 #include <linux/swap.h> 46 #include <linux/highmem.h> 47 #include <linux/pagemap.h> 48 #include <linux/rmap.h> 49 #include <linux/module.h> 50 #include <linux/delayacct.h> 51 #include <linux/init.h> 52 #include <linux/writeback.h> 53 54 #include <asm/pgalloc.h> 55 #include <asm/uaccess.h> 56 #include <asm/tlb.h> 57 #include <asm/tlbflush.h> 58 #include <asm/pgtable.h> 59 60 #include <linux/swapops.h> 61 #include <linux/elf.h> 62 63 #ifndef CONFIG_NEED_MULTIPLE_NODES 64 /* use the per-pgdat data instead for discontigmem - mbligh */ 65 unsigned long max_mapnr; 66 struct page *mem_map; 67 68 EXPORT_SYMBOL(max_mapnr); 69 EXPORT_SYMBOL(mem_map); 70 #endif 71 72 unsigned long num_physpages; 73 /* 74 * A number of key systems in x86 including ioremap() rely on the assumption 75 * that high_memory defines the upper bound on direct map memory, then end 76 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 77 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 78 * and ZONE_HIGHMEM. 79 */ 80 void * high_memory; 81 unsigned long vmalloc_earlyreserve; 82 83 EXPORT_SYMBOL(num_physpages); 84 EXPORT_SYMBOL(high_memory); 85 EXPORT_SYMBOL(vmalloc_earlyreserve); 86 87 int randomize_va_space __read_mostly = 1; 88 89 static int __init disable_randmaps(char *s) 90 { 91 randomize_va_space = 0; 92 return 1; 93 } 94 __setup("norandmaps", disable_randmaps); 95 96 97 /* 98 * If a p?d_bad entry is found while walking page tables, report 99 * the error, before resetting entry to p?d_none. Usually (but 100 * very seldom) called out from the p?d_none_or_clear_bad macros. 101 */ 102 103 void pgd_clear_bad(pgd_t *pgd) 104 { 105 pgd_ERROR(*pgd); 106 pgd_clear(pgd); 107 } 108 109 void pud_clear_bad(pud_t *pud) 110 { 111 pud_ERROR(*pud); 112 pud_clear(pud); 113 } 114 115 void pmd_clear_bad(pmd_t *pmd) 116 { 117 pmd_ERROR(*pmd); 118 pmd_clear(pmd); 119 } 120 121 /* 122 * Note: this doesn't free the actual pages themselves. That 123 * has been handled earlier when unmapping all the memory regions. 124 */ 125 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) 126 { 127 struct page *page = pmd_page(*pmd); 128 pmd_clear(pmd); 129 pte_lock_deinit(page); 130 pte_free_tlb(tlb, page); 131 dec_zone_page_state(page, NR_PAGETABLE); 132 tlb->mm->nr_ptes--; 133 } 134 135 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 136 unsigned long addr, unsigned long end, 137 unsigned long floor, unsigned long ceiling) 138 { 139 pmd_t *pmd; 140 unsigned long next; 141 unsigned long start; 142 143 start = addr; 144 pmd = pmd_offset(pud, addr); 145 do { 146 next = pmd_addr_end(addr, end); 147 if (pmd_none_or_clear_bad(pmd)) 148 continue; 149 free_pte_range(tlb, pmd); 150 } while (pmd++, addr = next, addr != end); 151 152 start &= PUD_MASK; 153 if (start < floor) 154 return; 155 if (ceiling) { 156 ceiling &= PUD_MASK; 157 if (!ceiling) 158 return; 159 } 160 if (end - 1 > ceiling - 1) 161 return; 162 163 pmd = pmd_offset(pud, start); 164 pud_clear(pud); 165 pmd_free_tlb(tlb, pmd); 166 } 167 168 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 169 unsigned long addr, unsigned long end, 170 unsigned long floor, unsigned long ceiling) 171 { 172 pud_t *pud; 173 unsigned long next; 174 unsigned long start; 175 176 start = addr; 177 pud = pud_offset(pgd, addr); 178 do { 179 next = pud_addr_end(addr, end); 180 if (pud_none_or_clear_bad(pud)) 181 continue; 182 free_pmd_range(tlb, pud, addr, next, floor, ceiling); 183 } while (pud++, addr = next, addr != end); 184 185 start &= PGDIR_MASK; 186 if (start < floor) 187 return; 188 if (ceiling) { 189 ceiling &= PGDIR_MASK; 190 if (!ceiling) 191 return; 192 } 193 if (end - 1 > ceiling - 1) 194 return; 195 196 pud = pud_offset(pgd, start); 197 pgd_clear(pgd); 198 pud_free_tlb(tlb, pud); 199 } 200 201 /* 202 * This function frees user-level page tables of a process. 203 * 204 * Must be called with pagetable lock held. 205 */ 206 void free_pgd_range(struct mmu_gather **tlb, 207 unsigned long addr, unsigned long end, 208 unsigned long floor, unsigned long ceiling) 209 { 210 pgd_t *pgd; 211 unsigned long next; 212 unsigned long start; 213 214 /* 215 * The next few lines have given us lots of grief... 216 * 217 * Why are we testing PMD* at this top level? Because often 218 * there will be no work to do at all, and we'd prefer not to 219 * go all the way down to the bottom just to discover that. 220 * 221 * Why all these "- 1"s? Because 0 represents both the bottom 222 * of the address space and the top of it (using -1 for the 223 * top wouldn't help much: the masks would do the wrong thing). 224 * The rule is that addr 0 and floor 0 refer to the bottom of 225 * the address space, but end 0 and ceiling 0 refer to the top 226 * Comparisons need to use "end - 1" and "ceiling - 1" (though 227 * that end 0 case should be mythical). 228 * 229 * Wherever addr is brought up or ceiling brought down, we must 230 * be careful to reject "the opposite 0" before it confuses the 231 * subsequent tests. But what about where end is brought down 232 * by PMD_SIZE below? no, end can't go down to 0 there. 233 * 234 * Whereas we round start (addr) and ceiling down, by different 235 * masks at different levels, in order to test whether a table 236 * now has no other vmas using it, so can be freed, we don't 237 * bother to round floor or end up - the tests don't need that. 238 */ 239 240 addr &= PMD_MASK; 241 if (addr < floor) { 242 addr += PMD_SIZE; 243 if (!addr) 244 return; 245 } 246 if (ceiling) { 247 ceiling &= PMD_MASK; 248 if (!ceiling) 249 return; 250 } 251 if (end - 1 > ceiling - 1) 252 end -= PMD_SIZE; 253 if (addr > end - 1) 254 return; 255 256 start = addr; 257 pgd = pgd_offset((*tlb)->mm, addr); 258 do { 259 next = pgd_addr_end(addr, end); 260 if (pgd_none_or_clear_bad(pgd)) 261 continue; 262 free_pud_range(*tlb, pgd, addr, next, floor, ceiling); 263 } while (pgd++, addr = next, addr != end); 264 265 if (!(*tlb)->fullmm) 266 flush_tlb_pgtables((*tlb)->mm, start, end); 267 } 268 269 void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, 270 unsigned long floor, unsigned long ceiling) 271 { 272 while (vma) { 273 struct vm_area_struct *next = vma->vm_next; 274 unsigned long addr = vma->vm_start; 275 276 /* 277 * Hide vma from rmap and vmtruncate before freeing pgtables 278 */ 279 anon_vma_unlink(vma); 280 unlink_file_vma(vma); 281 282 if (is_vm_hugetlb_page(vma)) { 283 hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 284 floor, next? next->vm_start: ceiling); 285 } else { 286 /* 287 * Optimization: gather nearby vmas into one call down 288 */ 289 while (next && next->vm_start <= vma->vm_end + PMD_SIZE 290 && !is_vm_hugetlb_page(next)) { 291 vma = next; 292 next = vma->vm_next; 293 anon_vma_unlink(vma); 294 unlink_file_vma(vma); 295 } 296 free_pgd_range(tlb, addr, vma->vm_end, 297 floor, next? next->vm_start: ceiling); 298 } 299 vma = next; 300 } 301 } 302 303 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) 304 { 305 struct page *new = pte_alloc_one(mm, address); 306 if (!new) 307 return -ENOMEM; 308 309 pte_lock_init(new); 310 spin_lock(&mm->page_table_lock); 311 if (pmd_present(*pmd)) { /* Another has populated it */ 312 pte_lock_deinit(new); 313 pte_free(new); 314 } else { 315 mm->nr_ptes++; 316 inc_zone_page_state(new, NR_PAGETABLE); 317 pmd_populate(mm, pmd, new); 318 } 319 spin_unlock(&mm->page_table_lock); 320 return 0; 321 } 322 323 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) 324 { 325 pte_t *new = pte_alloc_one_kernel(&init_mm, address); 326 if (!new) 327 return -ENOMEM; 328 329 spin_lock(&init_mm.page_table_lock); 330 if (pmd_present(*pmd)) /* Another has populated it */ 331 pte_free_kernel(new); 332 else 333 pmd_populate_kernel(&init_mm, pmd, new); 334 spin_unlock(&init_mm.page_table_lock); 335 return 0; 336 } 337 338 static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) 339 { 340 if (file_rss) 341 add_mm_counter(mm, file_rss, file_rss); 342 if (anon_rss) 343 add_mm_counter(mm, anon_rss, anon_rss); 344 } 345 346 /* 347 * This function is called to print an error when a bad pte 348 * is found. For example, we might have a PFN-mapped pte in 349 * a region that doesn't allow it. 350 * 351 * The calling function must still handle the error. 352 */ 353 void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) 354 { 355 printk(KERN_ERR "Bad pte = %08llx, process = %s, " 356 "vm_flags = %lx, vaddr = %lx\n", 357 (long long)pte_val(pte), 358 (vma->vm_mm == current->mm ? current->comm : "???"), 359 vma->vm_flags, vaddr); 360 dump_stack(); 361 } 362 363 static inline int is_cow_mapping(unsigned int flags) 364 { 365 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 366 } 367 368 /* 369 * This function gets the "struct page" associated with a pte. 370 * 371 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping 372 * will have each page table entry just pointing to a raw page frame 373 * number, and as far as the VM layer is concerned, those do not have 374 * pages associated with them - even if the PFN might point to memory 375 * that otherwise is perfectly fine and has a "struct page". 376 * 377 * The way we recognize those mappings is through the rules set up 378 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set, 379 * and the vm_pgoff will point to the first PFN mapped: thus every 380 * page that is a raw mapping will always honor the rule 381 * 382 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 383 * 384 * and if that isn't true, the page has been COW'ed (in which case it 385 * _does_ have a "struct page" associated with it even if it is in a 386 * VM_PFNMAP range). 387 */ 388 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte) 389 { 390 unsigned long pfn = pte_pfn(pte); 391 392 if (unlikely(vma->vm_flags & VM_PFNMAP)) { 393 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT; 394 if (pfn == vma->vm_pgoff + off) 395 return NULL; 396 if (!is_cow_mapping(vma->vm_flags)) 397 return NULL; 398 } 399 400 /* 401 * Add some anal sanity checks for now. Eventually, 402 * we should just do "return pfn_to_page(pfn)", but 403 * in the meantime we check that we get a valid pfn, 404 * and that the resulting page looks ok. 405 */ 406 if (unlikely(!pfn_valid(pfn))) { 407 print_bad_pte(vma, pte, addr); 408 return NULL; 409 } 410 411 /* 412 * NOTE! We still have PageReserved() pages in the page 413 * tables. 414 * 415 * The PAGE_ZERO() pages and various VDSO mappings can 416 * cause them to exist. 417 */ 418 return pfn_to_page(pfn); 419 } 420 421 /* 422 * copy one vm_area from one task to the other. Assumes the page tables 423 * already present in the new task to be cleared in the whole range 424 * covered by this vma. 425 */ 426 427 static inline void 428 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 429 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, 430 unsigned long addr, int *rss) 431 { 432 unsigned long vm_flags = vma->vm_flags; 433 pte_t pte = *src_pte; 434 struct page *page; 435 436 /* pte contains position in swap or file, so copy. */ 437 if (unlikely(!pte_present(pte))) { 438 if (!pte_file(pte)) { 439 swp_entry_t entry = pte_to_swp_entry(pte); 440 441 swap_duplicate(entry); 442 /* make sure dst_mm is on swapoff's mmlist. */ 443 if (unlikely(list_empty(&dst_mm->mmlist))) { 444 spin_lock(&mmlist_lock); 445 if (list_empty(&dst_mm->mmlist)) 446 list_add(&dst_mm->mmlist, 447 &src_mm->mmlist); 448 spin_unlock(&mmlist_lock); 449 } 450 if (is_write_migration_entry(entry) && 451 is_cow_mapping(vm_flags)) { 452 /* 453 * COW mappings require pages in both parent 454 * and child to be set to read. 455 */ 456 make_migration_entry_read(&entry); 457 pte = swp_entry_to_pte(entry); 458 set_pte_at(src_mm, addr, src_pte, pte); 459 } 460 } 461 goto out_set_pte; 462 } 463 464 /* 465 * If it's a COW mapping, write protect it both 466 * in the parent and the child 467 */ 468 if (is_cow_mapping(vm_flags)) { 469 ptep_set_wrprotect(src_mm, addr, src_pte); 470 pte = pte_wrprotect(pte); 471 } 472 473 /* 474 * If it's a shared mapping, mark it clean in 475 * the child 476 */ 477 if (vm_flags & VM_SHARED) 478 pte = pte_mkclean(pte); 479 pte = pte_mkold(pte); 480 481 page = vm_normal_page(vma, addr, pte); 482 if (page) { 483 get_page(page); 484 page_dup_rmap(page); 485 rss[!!PageAnon(page)]++; 486 } 487 488 out_set_pte: 489 set_pte_at(dst_mm, addr, dst_pte, pte); 490 } 491 492 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 493 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 494 unsigned long addr, unsigned long end) 495 { 496 pte_t *src_pte, *dst_pte; 497 spinlock_t *src_ptl, *dst_ptl; 498 int progress = 0; 499 int rss[2]; 500 501 again: 502 rss[1] = rss[0] = 0; 503 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 504 if (!dst_pte) 505 return -ENOMEM; 506 src_pte = pte_offset_map_nested(src_pmd, addr); 507 src_ptl = pte_lockptr(src_mm, src_pmd); 508 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 509 arch_enter_lazy_mmu_mode(); 510 511 do { 512 /* 513 * We are holding two locks at this point - either of them 514 * could generate latencies in another task on another CPU. 515 */ 516 if (progress >= 32) { 517 progress = 0; 518 if (need_resched() || 519 need_lockbreak(src_ptl) || 520 need_lockbreak(dst_ptl)) 521 break; 522 } 523 if (pte_none(*src_pte)) { 524 progress++; 525 continue; 526 } 527 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); 528 progress += 8; 529 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 530 531 arch_leave_lazy_mmu_mode(); 532 spin_unlock(src_ptl); 533 pte_unmap_nested(src_pte - 1); 534 add_mm_rss(dst_mm, rss[0], rss[1]); 535 pte_unmap_unlock(dst_pte - 1, dst_ptl); 536 cond_resched(); 537 if (addr != end) 538 goto again; 539 return 0; 540 } 541 542 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 543 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 544 unsigned long addr, unsigned long end) 545 { 546 pmd_t *src_pmd, *dst_pmd; 547 unsigned long next; 548 549 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 550 if (!dst_pmd) 551 return -ENOMEM; 552 src_pmd = pmd_offset(src_pud, addr); 553 do { 554 next = pmd_addr_end(addr, end); 555 if (pmd_none_or_clear_bad(src_pmd)) 556 continue; 557 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 558 vma, addr, next)) 559 return -ENOMEM; 560 } while (dst_pmd++, src_pmd++, addr = next, addr != end); 561 return 0; 562 } 563 564 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 565 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 566 unsigned long addr, unsigned long end) 567 { 568 pud_t *src_pud, *dst_pud; 569 unsigned long next; 570 571 dst_pud = pud_alloc(dst_mm, dst_pgd, addr); 572 if (!dst_pud) 573 return -ENOMEM; 574 src_pud = pud_offset(src_pgd, addr); 575 do { 576 next = pud_addr_end(addr, end); 577 if (pud_none_or_clear_bad(src_pud)) 578 continue; 579 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 580 vma, addr, next)) 581 return -ENOMEM; 582 } while (dst_pud++, src_pud++, addr = next, addr != end); 583 return 0; 584 } 585 586 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 587 struct vm_area_struct *vma) 588 { 589 pgd_t *src_pgd, *dst_pgd; 590 unsigned long next; 591 unsigned long addr = vma->vm_start; 592 unsigned long end = vma->vm_end; 593 594 /* 595 * Don't copy ptes where a page fault will fill them correctly. 596 * Fork becomes much lighter when there are big shared or private 597 * readonly mappings. The tradeoff is that copy_page_range is more 598 * efficient than faulting. 599 */ 600 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { 601 if (!vma->anon_vma) 602 return 0; 603 } 604 605 if (is_vm_hugetlb_page(vma)) 606 return copy_hugetlb_page_range(dst_mm, src_mm, vma); 607 608 dst_pgd = pgd_offset(dst_mm, addr); 609 src_pgd = pgd_offset(src_mm, addr); 610 do { 611 next = pgd_addr_end(addr, end); 612 if (pgd_none_or_clear_bad(src_pgd)) 613 continue; 614 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, 615 vma, addr, next)) 616 return -ENOMEM; 617 } while (dst_pgd++, src_pgd++, addr = next, addr != end); 618 return 0; 619 } 620 621 static unsigned long zap_pte_range(struct mmu_gather *tlb, 622 struct vm_area_struct *vma, pmd_t *pmd, 623 unsigned long addr, unsigned long end, 624 long *zap_work, struct zap_details *details) 625 { 626 struct mm_struct *mm = tlb->mm; 627 pte_t *pte; 628 spinlock_t *ptl; 629 int file_rss = 0; 630 int anon_rss = 0; 631 632 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 633 arch_enter_lazy_mmu_mode(); 634 do { 635 pte_t ptent = *pte; 636 if (pte_none(ptent)) { 637 (*zap_work)--; 638 continue; 639 } 640 641 (*zap_work) -= PAGE_SIZE; 642 643 if (pte_present(ptent)) { 644 struct page *page; 645 646 page = vm_normal_page(vma, addr, ptent); 647 if (unlikely(details) && page) { 648 /* 649 * unmap_shared_mapping_pages() wants to 650 * invalidate cache without truncating: 651 * unmap shared but keep private pages. 652 */ 653 if (details->check_mapping && 654 details->check_mapping != page->mapping) 655 continue; 656 /* 657 * Each page->index must be checked when 658 * invalidating or truncating nonlinear. 659 */ 660 if (details->nonlinear_vma && 661 (page->index < details->first_index || 662 page->index > details->last_index)) 663 continue; 664 } 665 ptent = ptep_get_and_clear_full(mm, addr, pte, 666 tlb->fullmm); 667 tlb_remove_tlb_entry(tlb, pte, addr); 668 if (unlikely(!page)) 669 continue; 670 if (unlikely(details) && details->nonlinear_vma 671 && linear_page_index(details->nonlinear_vma, 672 addr) != page->index) 673 set_pte_at(mm, addr, pte, 674 pgoff_to_pte(page->index)); 675 if (PageAnon(page)) 676 anon_rss--; 677 else { 678 if (pte_dirty(ptent)) 679 set_page_dirty(page); 680 if (pte_young(ptent)) 681 SetPageReferenced(page); 682 file_rss--; 683 } 684 page_remove_rmap(page, vma); 685 tlb_remove_page(tlb, page); 686 continue; 687 } 688 /* 689 * If details->check_mapping, we leave swap entries; 690 * if details->nonlinear_vma, we leave file entries. 691 */ 692 if (unlikely(details)) 693 continue; 694 if (!pte_file(ptent)) 695 free_swap_and_cache(pte_to_swp_entry(ptent)); 696 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 697 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); 698 699 add_mm_rss(mm, file_rss, anon_rss); 700 arch_leave_lazy_mmu_mode(); 701 pte_unmap_unlock(pte - 1, ptl); 702 703 return addr; 704 } 705 706 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 707 struct vm_area_struct *vma, pud_t *pud, 708 unsigned long addr, unsigned long end, 709 long *zap_work, struct zap_details *details) 710 { 711 pmd_t *pmd; 712 unsigned long next; 713 714 pmd = pmd_offset(pud, addr); 715 do { 716 next = pmd_addr_end(addr, end); 717 if (pmd_none_or_clear_bad(pmd)) { 718 (*zap_work)--; 719 continue; 720 } 721 next = zap_pte_range(tlb, vma, pmd, addr, next, 722 zap_work, details); 723 } while (pmd++, addr = next, (addr != end && *zap_work > 0)); 724 725 return addr; 726 } 727 728 static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 729 struct vm_area_struct *vma, pgd_t *pgd, 730 unsigned long addr, unsigned long end, 731 long *zap_work, struct zap_details *details) 732 { 733 pud_t *pud; 734 unsigned long next; 735 736 pud = pud_offset(pgd, addr); 737 do { 738 next = pud_addr_end(addr, end); 739 if (pud_none_or_clear_bad(pud)) { 740 (*zap_work)--; 741 continue; 742 } 743 next = zap_pmd_range(tlb, vma, pud, addr, next, 744 zap_work, details); 745 } while (pud++, addr = next, (addr != end && *zap_work > 0)); 746 747 return addr; 748 } 749 750 static unsigned long unmap_page_range(struct mmu_gather *tlb, 751 struct vm_area_struct *vma, 752 unsigned long addr, unsigned long end, 753 long *zap_work, struct zap_details *details) 754 { 755 pgd_t *pgd; 756 unsigned long next; 757 758 if (details && !details->check_mapping && !details->nonlinear_vma) 759 details = NULL; 760 761 BUG_ON(addr >= end); 762 tlb_start_vma(tlb, vma); 763 pgd = pgd_offset(vma->vm_mm, addr); 764 do { 765 next = pgd_addr_end(addr, end); 766 if (pgd_none_or_clear_bad(pgd)) { 767 (*zap_work)--; 768 continue; 769 } 770 next = zap_pud_range(tlb, vma, pgd, addr, next, 771 zap_work, details); 772 } while (pgd++, addr = next, (addr != end && *zap_work > 0)); 773 tlb_end_vma(tlb, vma); 774 775 return addr; 776 } 777 778 #ifdef CONFIG_PREEMPT 779 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) 780 #else 781 /* No preempt: go for improved straight-line efficiency */ 782 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) 783 #endif 784 785 /** 786 * unmap_vmas - unmap a range of memory covered by a list of vma's 787 * @tlbp: address of the caller's struct mmu_gather 788 * @vma: the starting vma 789 * @start_addr: virtual address at which to start unmapping 790 * @end_addr: virtual address at which to end unmapping 791 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here 792 * @details: details of nonlinear truncation or shared cache invalidation 793 * 794 * Returns the end address of the unmapping (restart addr if interrupted). 795 * 796 * Unmap all pages in the vma list. 797 * 798 * We aim to not hold locks for too long (for scheduling latency reasons). 799 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to 800 * return the ending mmu_gather to the caller. 801 * 802 * Only addresses between `start' and `end' will be unmapped. 803 * 804 * The VMA list must be sorted in ascending virtual address order. 805 * 806 * unmap_vmas() assumes that the caller will flush the whole unmapped address 807 * range after unmap_vmas() returns. So the only responsibility here is to 808 * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 809 * drops the lock and schedules. 810 */ 811 unsigned long unmap_vmas(struct mmu_gather **tlbp, 812 struct vm_area_struct *vma, unsigned long start_addr, 813 unsigned long end_addr, unsigned long *nr_accounted, 814 struct zap_details *details) 815 { 816 long zap_work = ZAP_BLOCK_SIZE; 817 unsigned long tlb_start = 0; /* For tlb_finish_mmu */ 818 int tlb_start_valid = 0; 819 unsigned long start = start_addr; 820 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; 821 int fullmm = (*tlbp)->fullmm; 822 823 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { 824 unsigned long end; 825 826 start = max(vma->vm_start, start_addr); 827 if (start >= vma->vm_end) 828 continue; 829 end = min(vma->vm_end, end_addr); 830 if (end <= vma->vm_start) 831 continue; 832 833 if (vma->vm_flags & VM_ACCOUNT) 834 *nr_accounted += (end - start) >> PAGE_SHIFT; 835 836 while (start != end) { 837 if (!tlb_start_valid) { 838 tlb_start = start; 839 tlb_start_valid = 1; 840 } 841 842 if (unlikely(is_vm_hugetlb_page(vma))) { 843 unmap_hugepage_range(vma, start, end); 844 zap_work -= (end - start) / 845 (HPAGE_SIZE / PAGE_SIZE); 846 start = end; 847 } else 848 start = unmap_page_range(*tlbp, vma, 849 start, end, &zap_work, details); 850 851 if (zap_work > 0) { 852 BUG_ON(start != end); 853 break; 854 } 855 856 tlb_finish_mmu(*tlbp, tlb_start, start); 857 858 if (need_resched() || 859 (i_mmap_lock && need_lockbreak(i_mmap_lock))) { 860 if (i_mmap_lock) { 861 *tlbp = NULL; 862 goto out; 863 } 864 cond_resched(); 865 } 866 867 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); 868 tlb_start_valid = 0; 869 zap_work = ZAP_BLOCK_SIZE; 870 } 871 } 872 out: 873 return start; /* which is now the end (or restart) address */ 874 } 875 876 /** 877 * zap_page_range - remove user pages in a given range 878 * @vma: vm_area_struct holding the applicable pages 879 * @address: starting address of pages to zap 880 * @size: number of bytes to zap 881 * @details: details of nonlinear truncation or shared cache invalidation 882 */ 883 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, 884 unsigned long size, struct zap_details *details) 885 { 886 struct mm_struct *mm = vma->vm_mm; 887 struct mmu_gather *tlb; 888 unsigned long end = address + size; 889 unsigned long nr_accounted = 0; 890 891 lru_add_drain(); 892 tlb = tlb_gather_mmu(mm, 0); 893 update_hiwater_rss(mm); 894 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); 895 if (tlb) 896 tlb_finish_mmu(tlb, address, end); 897 return end; 898 } 899 900 /* 901 * Do a quick page-table lookup for a single page. 902 */ 903 struct page *follow_page(struct vm_area_struct *vma, unsigned long address, 904 unsigned int flags) 905 { 906 pgd_t *pgd; 907 pud_t *pud; 908 pmd_t *pmd; 909 pte_t *ptep, pte; 910 spinlock_t *ptl; 911 struct page *page; 912 struct mm_struct *mm = vma->vm_mm; 913 914 page = follow_huge_addr(mm, address, flags & FOLL_WRITE); 915 if (!IS_ERR(page)) { 916 BUG_ON(flags & FOLL_GET); 917 goto out; 918 } 919 920 page = NULL; 921 pgd = pgd_offset(mm, address); 922 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 923 goto no_page_table; 924 925 pud = pud_offset(pgd, address); 926 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 927 goto no_page_table; 928 929 pmd = pmd_offset(pud, address); 930 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 931 goto no_page_table; 932 933 if (pmd_huge(*pmd)) { 934 BUG_ON(flags & FOLL_GET); 935 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); 936 goto out; 937 } 938 939 ptep = pte_offset_map_lock(mm, pmd, address, &ptl); 940 if (!ptep) 941 goto out; 942 943 pte = *ptep; 944 if (!pte_present(pte)) 945 goto unlock; 946 if ((flags & FOLL_WRITE) && !pte_write(pte)) 947 goto unlock; 948 page = vm_normal_page(vma, address, pte); 949 if (unlikely(!page)) 950 goto unlock; 951 952 if (flags & FOLL_GET) 953 get_page(page); 954 if (flags & FOLL_TOUCH) { 955 if ((flags & FOLL_WRITE) && 956 !pte_dirty(pte) && !PageDirty(page)) 957 set_page_dirty(page); 958 mark_page_accessed(page); 959 } 960 unlock: 961 pte_unmap_unlock(ptep, ptl); 962 out: 963 return page; 964 965 no_page_table: 966 /* 967 * When core dumping an enormous anonymous area that nobody 968 * has touched so far, we don't want to allocate page tables. 969 */ 970 if (flags & FOLL_ANON) { 971 page = ZERO_PAGE(address); 972 if (flags & FOLL_GET) 973 get_page(page); 974 BUG_ON(flags & FOLL_WRITE); 975 } 976 return page; 977 } 978 979 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 980 unsigned long start, int len, int write, int force, 981 struct page **pages, struct vm_area_struct **vmas) 982 { 983 int i; 984 unsigned int vm_flags; 985 986 /* 987 * Require read or write permissions. 988 * If 'force' is set, we only require the "MAY" flags. 989 */ 990 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 991 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 992 i = 0; 993 994 do { 995 struct vm_area_struct *vma; 996 unsigned int foll_flags; 997 998 vma = find_extend_vma(mm, start); 999 if (!vma && in_gate_area(tsk, start)) { 1000 unsigned long pg = start & PAGE_MASK; 1001 struct vm_area_struct *gate_vma = get_gate_vma(tsk); 1002 pgd_t *pgd; 1003 pud_t *pud; 1004 pmd_t *pmd; 1005 pte_t *pte; 1006 if (write) /* user gate pages are read-only */ 1007 return i ? : -EFAULT; 1008 if (pg > TASK_SIZE) 1009 pgd = pgd_offset_k(pg); 1010 else 1011 pgd = pgd_offset_gate(mm, pg); 1012 BUG_ON(pgd_none(*pgd)); 1013 pud = pud_offset(pgd, pg); 1014 BUG_ON(pud_none(*pud)); 1015 pmd = pmd_offset(pud, pg); 1016 if (pmd_none(*pmd)) 1017 return i ? : -EFAULT; 1018 pte = pte_offset_map(pmd, pg); 1019 if (pte_none(*pte)) { 1020 pte_unmap(pte); 1021 return i ? : -EFAULT; 1022 } 1023 if (pages) { 1024 struct page *page = vm_normal_page(gate_vma, start, *pte); 1025 pages[i] = page; 1026 if (page) 1027 get_page(page); 1028 } 1029 pte_unmap(pte); 1030 if (vmas) 1031 vmas[i] = gate_vma; 1032 i++; 1033 start += PAGE_SIZE; 1034 len--; 1035 continue; 1036 } 1037 1038 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) 1039 || !(vm_flags & vma->vm_flags)) 1040 return i ? : -EFAULT; 1041 1042 if (is_vm_hugetlb_page(vma)) { 1043 i = follow_hugetlb_page(mm, vma, pages, vmas, 1044 &start, &len, i); 1045 continue; 1046 } 1047 1048 foll_flags = FOLL_TOUCH; 1049 if (pages) 1050 foll_flags |= FOLL_GET; 1051 if (!write && !(vma->vm_flags & VM_LOCKED) && 1052 (!vma->vm_ops || !vma->vm_ops->nopage)) 1053 foll_flags |= FOLL_ANON; 1054 1055 do { 1056 struct page *page; 1057 1058 if (write) 1059 foll_flags |= FOLL_WRITE; 1060 1061 cond_resched(); 1062 while (!(page = follow_page(vma, start, foll_flags))) { 1063 int ret; 1064 ret = __handle_mm_fault(mm, vma, start, 1065 foll_flags & FOLL_WRITE); 1066 /* 1067 * The VM_FAULT_WRITE bit tells us that do_wp_page has 1068 * broken COW when necessary, even if maybe_mkwrite 1069 * decided not to set pte_write. We can thus safely do 1070 * subsequent page lookups as if they were reads. 1071 */ 1072 if (ret & VM_FAULT_WRITE) 1073 foll_flags &= ~FOLL_WRITE; 1074 1075 switch (ret & ~VM_FAULT_WRITE) { 1076 case VM_FAULT_MINOR: 1077 tsk->min_flt++; 1078 break; 1079 case VM_FAULT_MAJOR: 1080 tsk->maj_flt++; 1081 break; 1082 case VM_FAULT_SIGBUS: 1083 return i ? i : -EFAULT; 1084 case VM_FAULT_OOM: 1085 return i ? i : -ENOMEM; 1086 default: 1087 BUG(); 1088 } 1089 cond_resched(); 1090 } 1091 if (pages) { 1092 pages[i] = page; 1093 1094 flush_anon_page(vma, page, start); 1095 flush_dcache_page(page); 1096 } 1097 if (vmas) 1098 vmas[i] = vma; 1099 i++; 1100 start += PAGE_SIZE; 1101 len--; 1102 } while (len && start < vma->vm_end); 1103 } while (len); 1104 return i; 1105 } 1106 EXPORT_SYMBOL(get_user_pages); 1107 1108 static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1109 unsigned long addr, unsigned long end, pgprot_t prot) 1110 { 1111 pte_t *pte; 1112 spinlock_t *ptl; 1113 int err = 0; 1114 1115 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 1116 if (!pte) 1117 return -EAGAIN; 1118 arch_enter_lazy_mmu_mode(); 1119 do { 1120 struct page *page = ZERO_PAGE(addr); 1121 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot)); 1122 1123 if (unlikely(!pte_none(*pte))) { 1124 err = -EEXIST; 1125 pte++; 1126 break; 1127 } 1128 page_cache_get(page); 1129 page_add_file_rmap(page); 1130 inc_mm_counter(mm, file_rss); 1131 set_pte_at(mm, addr, pte, zero_pte); 1132 } while (pte++, addr += PAGE_SIZE, addr != end); 1133 arch_leave_lazy_mmu_mode(); 1134 pte_unmap_unlock(pte - 1, ptl); 1135 return err; 1136 } 1137 1138 static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, 1139 unsigned long addr, unsigned long end, pgprot_t prot) 1140 { 1141 pmd_t *pmd; 1142 unsigned long next; 1143 int err; 1144 1145 pmd = pmd_alloc(mm, pud, addr); 1146 if (!pmd) 1147 return -EAGAIN; 1148 do { 1149 next = pmd_addr_end(addr, end); 1150 err = zeromap_pte_range(mm, pmd, addr, next, prot); 1151 if (err) 1152 break; 1153 } while (pmd++, addr = next, addr != end); 1154 return err; 1155 } 1156 1157 static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1158 unsigned long addr, unsigned long end, pgprot_t prot) 1159 { 1160 pud_t *pud; 1161 unsigned long next; 1162 int err; 1163 1164 pud = pud_alloc(mm, pgd, addr); 1165 if (!pud) 1166 return -EAGAIN; 1167 do { 1168 next = pud_addr_end(addr, end); 1169 err = zeromap_pmd_range(mm, pud, addr, next, prot); 1170 if (err) 1171 break; 1172 } while (pud++, addr = next, addr != end); 1173 return err; 1174 } 1175 1176 int zeromap_page_range(struct vm_area_struct *vma, 1177 unsigned long addr, unsigned long size, pgprot_t prot) 1178 { 1179 pgd_t *pgd; 1180 unsigned long next; 1181 unsigned long end = addr + size; 1182 struct mm_struct *mm = vma->vm_mm; 1183 int err; 1184 1185 BUG_ON(addr >= end); 1186 pgd = pgd_offset(mm, addr); 1187 flush_cache_range(vma, addr, end); 1188 do { 1189 next = pgd_addr_end(addr, end); 1190 err = zeromap_pud_range(mm, pgd, addr, next, prot); 1191 if (err) 1192 break; 1193 } while (pgd++, addr = next, addr != end); 1194 return err; 1195 } 1196 1197 pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl) 1198 { 1199 pgd_t * pgd = pgd_offset(mm, addr); 1200 pud_t * pud = pud_alloc(mm, pgd, addr); 1201 if (pud) { 1202 pmd_t * pmd = pmd_alloc(mm, pud, addr); 1203 if (pmd) 1204 return pte_alloc_map_lock(mm, pmd, addr, ptl); 1205 } 1206 return NULL; 1207 } 1208 1209 /* 1210 * This is the old fallback for page remapping. 1211 * 1212 * For historical reasons, it only allows reserved pages. Only 1213 * old drivers should use this, and they needed to mark their 1214 * pages reserved for the old functions anyway. 1215 */ 1216 static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot) 1217 { 1218 int retval; 1219 pte_t *pte; 1220 spinlock_t *ptl; 1221 1222 retval = -EINVAL; 1223 if (PageAnon(page)) 1224 goto out; 1225 retval = -ENOMEM; 1226 flush_dcache_page(page); 1227 pte = get_locked_pte(mm, addr, &ptl); 1228 if (!pte) 1229 goto out; 1230 retval = -EBUSY; 1231 if (!pte_none(*pte)) 1232 goto out_unlock; 1233 1234 /* Ok, finally just insert the thing.. */ 1235 get_page(page); 1236 inc_mm_counter(mm, file_rss); 1237 page_add_file_rmap(page); 1238 set_pte_at(mm, addr, pte, mk_pte(page, prot)); 1239 1240 retval = 0; 1241 out_unlock: 1242 pte_unmap_unlock(pte, ptl); 1243 out: 1244 return retval; 1245 } 1246 1247 /** 1248 * vm_insert_page - insert single page into user vma 1249 * @vma: user vma to map to 1250 * @addr: target user address of this page 1251 * @page: source kernel page 1252 * 1253 * This allows drivers to insert individual pages they've allocated 1254 * into a user vma. 1255 * 1256 * The page has to be a nice clean _individual_ kernel allocation. 1257 * If you allocate a compound page, you need to have marked it as 1258 * such (__GFP_COMP), or manually just split the page up yourself 1259 * (see split_page()). 1260 * 1261 * NOTE! Traditionally this was done with "remap_pfn_range()" which 1262 * took an arbitrary page protection parameter. This doesn't allow 1263 * that. Your vma protection will have to be set up correctly, which 1264 * means that if you want a shared writable mapping, you'd better 1265 * ask for a shared writable mapping! 1266 * 1267 * The page does not need to be reserved. 1268 */ 1269 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) 1270 { 1271 if (addr < vma->vm_start || addr >= vma->vm_end) 1272 return -EFAULT; 1273 if (!page_count(page)) 1274 return -EINVAL; 1275 vma->vm_flags |= VM_INSERTPAGE; 1276 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot); 1277 } 1278 EXPORT_SYMBOL(vm_insert_page); 1279 1280 /** 1281 * vm_insert_pfn - insert single pfn into user vma 1282 * @vma: user vma to map to 1283 * @addr: target user address of this page 1284 * @pfn: source kernel pfn 1285 * 1286 * Similar to vm_inert_page, this allows drivers to insert individual pages 1287 * they've allocated into a user vma. Same comments apply. 1288 * 1289 * This function should only be called from a vm_ops->fault handler, and 1290 * in that case the handler should return NULL. 1291 */ 1292 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 1293 unsigned long pfn) 1294 { 1295 struct mm_struct *mm = vma->vm_mm; 1296 int retval; 1297 pte_t *pte, entry; 1298 spinlock_t *ptl; 1299 1300 BUG_ON(!(vma->vm_flags & VM_PFNMAP)); 1301 BUG_ON(is_cow_mapping(vma->vm_flags)); 1302 1303 retval = -ENOMEM; 1304 pte = get_locked_pte(mm, addr, &ptl); 1305 if (!pte) 1306 goto out; 1307 retval = -EBUSY; 1308 if (!pte_none(*pte)) 1309 goto out_unlock; 1310 1311 /* Ok, finally just insert the thing.. */ 1312 entry = pfn_pte(pfn, vma->vm_page_prot); 1313 set_pte_at(mm, addr, pte, entry); 1314 update_mmu_cache(vma, addr, entry); 1315 1316 retval = 0; 1317 out_unlock: 1318 pte_unmap_unlock(pte, ptl); 1319 1320 out: 1321 return retval; 1322 } 1323 EXPORT_SYMBOL(vm_insert_pfn); 1324 1325 /* 1326 * maps a range of physical memory into the requested pages. the old 1327 * mappings are removed. any references to nonexistent pages results 1328 * in null mappings (currently treated as "copy-on-access") 1329 */ 1330 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1331 unsigned long addr, unsigned long end, 1332 unsigned long pfn, pgprot_t prot) 1333 { 1334 pte_t *pte; 1335 spinlock_t *ptl; 1336 1337 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 1338 if (!pte) 1339 return -ENOMEM; 1340 arch_enter_lazy_mmu_mode(); 1341 do { 1342 BUG_ON(!pte_none(*pte)); 1343 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); 1344 pfn++; 1345 } while (pte++, addr += PAGE_SIZE, addr != end); 1346 arch_leave_lazy_mmu_mode(); 1347 pte_unmap_unlock(pte - 1, ptl); 1348 return 0; 1349 } 1350 1351 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 1352 unsigned long addr, unsigned long end, 1353 unsigned long pfn, pgprot_t prot) 1354 { 1355 pmd_t *pmd; 1356 unsigned long next; 1357 1358 pfn -= addr >> PAGE_SHIFT; 1359 pmd = pmd_alloc(mm, pud, addr); 1360 if (!pmd) 1361 return -ENOMEM; 1362 do { 1363 next = pmd_addr_end(addr, end); 1364 if (remap_pte_range(mm, pmd, addr, next, 1365 pfn + (addr >> PAGE_SHIFT), prot)) 1366 return -ENOMEM; 1367 } while (pmd++, addr = next, addr != end); 1368 return 0; 1369 } 1370 1371 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1372 unsigned long addr, unsigned long end, 1373 unsigned long pfn, pgprot_t prot) 1374 { 1375 pud_t *pud; 1376 unsigned long next; 1377 1378 pfn -= addr >> PAGE_SHIFT; 1379 pud = pud_alloc(mm, pgd, addr); 1380 if (!pud) 1381 return -ENOMEM; 1382 do { 1383 next = pud_addr_end(addr, end); 1384 if (remap_pmd_range(mm, pud, addr, next, 1385 pfn + (addr >> PAGE_SHIFT), prot)) 1386 return -ENOMEM; 1387 } while (pud++, addr = next, addr != end); 1388 return 0; 1389 } 1390 1391 /** 1392 * remap_pfn_range - remap kernel memory to userspace 1393 * @vma: user vma to map to 1394 * @addr: target user address to start at 1395 * @pfn: physical address of kernel memory 1396 * @size: size of map area 1397 * @prot: page protection flags for this mapping 1398 * 1399 * Note: this is only safe if the mm semaphore is held when called. 1400 */ 1401 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 1402 unsigned long pfn, unsigned long size, pgprot_t prot) 1403 { 1404 pgd_t *pgd; 1405 unsigned long next; 1406 unsigned long end = addr + PAGE_ALIGN(size); 1407 struct mm_struct *mm = vma->vm_mm; 1408 int err; 1409 1410 /* 1411 * Physically remapped pages are special. Tell the 1412 * rest of the world about it: 1413 * VM_IO tells people not to look at these pages 1414 * (accesses can have side effects). 1415 * VM_RESERVED is specified all over the place, because 1416 * in 2.4 it kept swapout's vma scan off this vma; but 1417 * in 2.6 the LRU scan won't even find its pages, so this 1418 * flag means no more than count its pages in reserved_vm, 1419 * and omit it from core dump, even when VM_IO turned off. 1420 * VM_PFNMAP tells the core MM that the base pages are just 1421 * raw PFN mappings, and do not have a "struct page" associated 1422 * with them. 1423 * 1424 * There's a horrible special case to handle copy-on-write 1425 * behaviour that some programs depend on. We mark the "original" 1426 * un-COW'ed pages by matching them up with "vma->vm_pgoff". 1427 */ 1428 if (is_cow_mapping(vma->vm_flags)) { 1429 if (addr != vma->vm_start || end != vma->vm_end) 1430 return -EINVAL; 1431 vma->vm_pgoff = pfn; 1432 } 1433 1434 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; 1435 1436 BUG_ON(addr >= end); 1437 pfn -= addr >> PAGE_SHIFT; 1438 pgd = pgd_offset(mm, addr); 1439 flush_cache_range(vma, addr, end); 1440 do { 1441 next = pgd_addr_end(addr, end); 1442 err = remap_pud_range(mm, pgd, addr, next, 1443 pfn + (addr >> PAGE_SHIFT), prot); 1444 if (err) 1445 break; 1446 } while (pgd++, addr = next, addr != end); 1447 return err; 1448 } 1449 EXPORT_SYMBOL(remap_pfn_range); 1450 1451 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 1452 unsigned long addr, unsigned long end, 1453 pte_fn_t fn, void *data) 1454 { 1455 pte_t *pte; 1456 int err; 1457 struct page *pmd_page; 1458 spinlock_t *uninitialized_var(ptl); 1459 1460 pte = (mm == &init_mm) ? 1461 pte_alloc_kernel(pmd, addr) : 1462 pte_alloc_map_lock(mm, pmd, addr, &ptl); 1463 if (!pte) 1464 return -ENOMEM; 1465 1466 BUG_ON(pmd_huge(*pmd)); 1467 1468 pmd_page = pmd_page(*pmd); 1469 1470 do { 1471 err = fn(pte, pmd_page, addr, data); 1472 if (err) 1473 break; 1474 } while (pte++, addr += PAGE_SIZE, addr != end); 1475 1476 if (mm != &init_mm) 1477 pte_unmap_unlock(pte-1, ptl); 1478 return err; 1479 } 1480 1481 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 1482 unsigned long addr, unsigned long end, 1483 pte_fn_t fn, void *data) 1484 { 1485 pmd_t *pmd; 1486 unsigned long next; 1487 int err; 1488 1489 pmd = pmd_alloc(mm, pud, addr); 1490 if (!pmd) 1491 return -ENOMEM; 1492 do { 1493 next = pmd_addr_end(addr, end); 1494 err = apply_to_pte_range(mm, pmd, addr, next, fn, data); 1495 if (err) 1496 break; 1497 } while (pmd++, addr = next, addr != end); 1498 return err; 1499 } 1500 1501 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, 1502 unsigned long addr, unsigned long end, 1503 pte_fn_t fn, void *data) 1504 { 1505 pud_t *pud; 1506 unsigned long next; 1507 int err; 1508 1509 pud = pud_alloc(mm, pgd, addr); 1510 if (!pud) 1511 return -ENOMEM; 1512 do { 1513 next = pud_addr_end(addr, end); 1514 err = apply_to_pmd_range(mm, pud, addr, next, fn, data); 1515 if (err) 1516 break; 1517 } while (pud++, addr = next, addr != end); 1518 return err; 1519 } 1520 1521 /* 1522 * Scan a region of virtual memory, filling in page tables as necessary 1523 * and calling a provided function on each leaf page table. 1524 */ 1525 int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 1526 unsigned long size, pte_fn_t fn, void *data) 1527 { 1528 pgd_t *pgd; 1529 unsigned long next; 1530 unsigned long end = addr + size; 1531 int err; 1532 1533 BUG_ON(addr >= end); 1534 pgd = pgd_offset(mm, addr); 1535 do { 1536 next = pgd_addr_end(addr, end); 1537 err = apply_to_pud_range(mm, pgd, addr, next, fn, data); 1538 if (err) 1539 break; 1540 } while (pgd++, addr = next, addr != end); 1541 return err; 1542 } 1543 EXPORT_SYMBOL_GPL(apply_to_page_range); 1544 1545 /* 1546 * handle_pte_fault chooses page fault handler according to an entry 1547 * which was read non-atomically. Before making any commitment, on 1548 * those architectures or configurations (e.g. i386 with PAE) which 1549 * might give a mix of unmatched parts, do_swap_page and do_file_page 1550 * must check under lock before unmapping the pte and proceeding 1551 * (but do_wp_page is only called after already making such a check; 1552 * and do_anonymous_page and do_no_page can safely check later on). 1553 */ 1554 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, 1555 pte_t *page_table, pte_t orig_pte) 1556 { 1557 int same = 1; 1558 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) 1559 if (sizeof(pte_t) > sizeof(unsigned long)) { 1560 spinlock_t *ptl = pte_lockptr(mm, pmd); 1561 spin_lock(ptl); 1562 same = pte_same(*page_table, orig_pte); 1563 spin_unlock(ptl); 1564 } 1565 #endif 1566 pte_unmap(page_table); 1567 return same; 1568 } 1569 1570 /* 1571 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when 1572 * servicing faults for write access. In the normal case, do always want 1573 * pte_mkwrite. But get_user_pages can cause write faults for mappings 1574 * that do not have writing enabled, when used by access_process_vm. 1575 */ 1576 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 1577 { 1578 if (likely(vma->vm_flags & VM_WRITE)) 1579 pte = pte_mkwrite(pte); 1580 return pte; 1581 } 1582 1583 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) 1584 { 1585 /* 1586 * If the source page was a PFN mapping, we don't have 1587 * a "struct page" for it. We do a best-effort copy by 1588 * just copying from the original user address. If that 1589 * fails, we just zero-fill it. Live with it. 1590 */ 1591 if (unlikely(!src)) { 1592 void *kaddr = kmap_atomic(dst, KM_USER0); 1593 void __user *uaddr = (void __user *)(va & PAGE_MASK); 1594 1595 /* 1596 * This really shouldn't fail, because the page is there 1597 * in the page tables. But it might just be unreadable, 1598 * in which case we just give up and fill the result with 1599 * zeroes. 1600 */ 1601 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) 1602 memset(kaddr, 0, PAGE_SIZE); 1603 kunmap_atomic(kaddr, KM_USER0); 1604 flush_dcache_page(dst); 1605 return; 1606 1607 } 1608 copy_user_highpage(dst, src, va, vma); 1609 } 1610 1611 /* 1612 * This routine handles present pages, when users try to write 1613 * to a shared page. It is done by copying the page to a new address 1614 * and decrementing the shared-page counter for the old page. 1615 * 1616 * Note that this routine assumes that the protection checks have been 1617 * done by the caller (the low-level page fault routine in most cases). 1618 * Thus we can safely just mark it writable once we've done any necessary 1619 * COW. 1620 * 1621 * We also mark the page dirty at this point even though the page will 1622 * change only once the write actually happens. This avoids a few races, 1623 * and potentially makes it more efficient. 1624 * 1625 * We enter with non-exclusive mmap_sem (to exclude vma changes, 1626 * but allow concurrent faults), with pte both mapped and locked. 1627 * We return with mmap_sem still held, but pte unmapped and unlocked. 1628 */ 1629 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 1630 unsigned long address, pte_t *page_table, pmd_t *pmd, 1631 spinlock_t *ptl, pte_t orig_pte) 1632 { 1633 struct page *old_page, *new_page; 1634 pte_t entry; 1635 int reuse = 0, ret = VM_FAULT_MINOR; 1636 struct page *dirty_page = NULL; 1637 1638 old_page = vm_normal_page(vma, address, orig_pte); 1639 if (!old_page) 1640 goto gotten; 1641 1642 /* 1643 * Take out anonymous pages first, anonymous shared vmas are 1644 * not dirty accountable. 1645 */ 1646 if (PageAnon(old_page)) { 1647 if (!TestSetPageLocked(old_page)) { 1648 reuse = can_share_swap_page(old_page); 1649 unlock_page(old_page); 1650 } 1651 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 1652 (VM_WRITE|VM_SHARED))) { 1653 /* 1654 * Only catch write-faults on shared writable pages, 1655 * read-only shared pages can get COWed by 1656 * get_user_pages(.write=1, .force=1). 1657 */ 1658 if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 1659 /* 1660 * Notify the address space that the page is about to 1661 * become writable so that it can prohibit this or wait 1662 * for the page to get into an appropriate state. 1663 * 1664 * We do this without the lock held, so that it can 1665 * sleep if it needs to. 1666 */ 1667 page_cache_get(old_page); 1668 pte_unmap_unlock(page_table, ptl); 1669 1670 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0) 1671 goto unwritable_page; 1672 1673 /* 1674 * Since we dropped the lock we need to revalidate 1675 * the PTE as someone else may have changed it. If 1676 * they did, we just return, as we can count on the 1677 * MMU to tell us if they didn't also make it writable. 1678 */ 1679 page_table = pte_offset_map_lock(mm, pmd, address, 1680 &ptl); 1681 page_cache_release(old_page); 1682 if (!pte_same(*page_table, orig_pte)) 1683 goto unlock; 1684 } 1685 dirty_page = old_page; 1686 get_page(dirty_page); 1687 reuse = 1; 1688 } 1689 1690 if (reuse) { 1691 flush_cache_page(vma, address, pte_pfn(orig_pte)); 1692 entry = pte_mkyoung(orig_pte); 1693 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1694 ptep_set_access_flags(vma, address, page_table, entry, 1); 1695 update_mmu_cache(vma, address, entry); 1696 lazy_mmu_prot_update(entry); 1697 ret |= VM_FAULT_WRITE; 1698 goto unlock; 1699 } 1700 1701 /* 1702 * Ok, we need to copy. Oh, well.. 1703 */ 1704 page_cache_get(old_page); 1705 gotten: 1706 pte_unmap_unlock(page_table, ptl); 1707 1708 if (unlikely(anon_vma_prepare(vma))) 1709 goto oom; 1710 if (old_page == ZERO_PAGE(address)) { 1711 new_page = alloc_zeroed_user_highpage(vma, address); 1712 if (!new_page) 1713 goto oom; 1714 } else { 1715 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1716 if (!new_page) 1717 goto oom; 1718 cow_user_page(new_page, old_page, address, vma); 1719 } 1720 1721 /* 1722 * Re-check the pte - we dropped the lock 1723 */ 1724 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 1725 if (likely(pte_same(*page_table, orig_pte))) { 1726 if (old_page) { 1727 page_remove_rmap(old_page, vma); 1728 if (!PageAnon(old_page)) { 1729 dec_mm_counter(mm, file_rss); 1730 inc_mm_counter(mm, anon_rss); 1731 } 1732 } else 1733 inc_mm_counter(mm, anon_rss); 1734 flush_cache_page(vma, address, pte_pfn(orig_pte)); 1735 entry = mk_pte(new_page, vma->vm_page_prot); 1736 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1737 lazy_mmu_prot_update(entry); 1738 /* 1739 * Clear the pte entry and flush it first, before updating the 1740 * pte with the new entry. This will avoid a race condition 1741 * seen in the presence of one thread doing SMC and another 1742 * thread doing COW. 1743 */ 1744 ptep_clear_flush(vma, address, page_table); 1745 set_pte_at(mm, address, page_table, entry); 1746 update_mmu_cache(vma, address, entry); 1747 lru_cache_add_active(new_page); 1748 page_add_new_anon_rmap(new_page, vma, address); 1749 1750 /* Free the old page.. */ 1751 new_page = old_page; 1752 ret |= VM_FAULT_WRITE; 1753 } 1754 if (new_page) 1755 page_cache_release(new_page); 1756 if (old_page) 1757 page_cache_release(old_page); 1758 unlock: 1759 pte_unmap_unlock(page_table, ptl); 1760 if (dirty_page) { 1761 set_page_dirty_balance(dirty_page); 1762 put_page(dirty_page); 1763 } 1764 return ret; 1765 oom: 1766 if (old_page) 1767 page_cache_release(old_page); 1768 return VM_FAULT_OOM; 1769 1770 unwritable_page: 1771 page_cache_release(old_page); 1772 return VM_FAULT_SIGBUS; 1773 } 1774 1775 /* 1776 * Helper functions for unmap_mapping_range(). 1777 * 1778 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ 1779 * 1780 * We have to restart searching the prio_tree whenever we drop the lock, 1781 * since the iterator is only valid while the lock is held, and anyway 1782 * a later vma might be split and reinserted earlier while lock dropped. 1783 * 1784 * The list of nonlinear vmas could be handled more efficiently, using 1785 * a placeholder, but handle it in the same way until a need is shown. 1786 * It is important to search the prio_tree before nonlinear list: a vma 1787 * may become nonlinear and be shifted from prio_tree to nonlinear list 1788 * while the lock is dropped; but never shifted from list to prio_tree. 1789 * 1790 * In order to make forward progress despite restarting the search, 1791 * vm_truncate_count is used to mark a vma as now dealt with, so we can 1792 * quickly skip it next time around. Since the prio_tree search only 1793 * shows us those vmas affected by unmapping the range in question, we 1794 * can't efficiently keep all vmas in step with mapping->truncate_count: 1795 * so instead reset them all whenever it wraps back to 0 (then go to 1). 1796 * mapping->truncate_count and vma->vm_truncate_count are protected by 1797 * i_mmap_lock. 1798 * 1799 * In order to make forward progress despite repeatedly restarting some 1800 * large vma, note the restart_addr from unmap_vmas when it breaks out: 1801 * and restart from that address when we reach that vma again. It might 1802 * have been split or merged, shrunk or extended, but never shifted: so 1803 * restart_addr remains valid so long as it remains in the vma's range. 1804 * unmap_mapping_range forces truncate_count to leap over page-aligned 1805 * values so we can save vma's restart_addr in its truncate_count field. 1806 */ 1807 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) 1808 1809 static void reset_vma_truncate_counts(struct address_space *mapping) 1810 { 1811 struct vm_area_struct *vma; 1812 struct prio_tree_iter iter; 1813 1814 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) 1815 vma->vm_truncate_count = 0; 1816 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) 1817 vma->vm_truncate_count = 0; 1818 } 1819 1820 static int unmap_mapping_range_vma(struct vm_area_struct *vma, 1821 unsigned long start_addr, unsigned long end_addr, 1822 struct zap_details *details) 1823 { 1824 unsigned long restart_addr; 1825 int need_break; 1826 1827 again: 1828 restart_addr = vma->vm_truncate_count; 1829 if (is_restart_addr(restart_addr) && start_addr < restart_addr) { 1830 start_addr = restart_addr; 1831 if (start_addr >= end_addr) { 1832 /* Top of vma has been split off since last time */ 1833 vma->vm_truncate_count = details->truncate_count; 1834 return 0; 1835 } 1836 } 1837 1838 restart_addr = zap_page_range(vma, start_addr, 1839 end_addr - start_addr, details); 1840 need_break = need_resched() || 1841 need_lockbreak(details->i_mmap_lock); 1842 1843 if (restart_addr >= end_addr) { 1844 /* We have now completed this vma: mark it so */ 1845 vma->vm_truncate_count = details->truncate_count; 1846 if (!need_break) 1847 return 0; 1848 } else { 1849 /* Note restart_addr in vma's truncate_count field */ 1850 vma->vm_truncate_count = restart_addr; 1851 if (!need_break) 1852 goto again; 1853 } 1854 1855 spin_unlock(details->i_mmap_lock); 1856 cond_resched(); 1857 spin_lock(details->i_mmap_lock); 1858 return -EINTR; 1859 } 1860 1861 static inline void unmap_mapping_range_tree(struct prio_tree_root *root, 1862 struct zap_details *details) 1863 { 1864 struct vm_area_struct *vma; 1865 struct prio_tree_iter iter; 1866 pgoff_t vba, vea, zba, zea; 1867 1868 restart: 1869 vma_prio_tree_foreach(vma, &iter, root, 1870 details->first_index, details->last_index) { 1871 /* Skip quickly over those we have already dealt with */ 1872 if (vma->vm_truncate_count == details->truncate_count) 1873 continue; 1874 1875 vba = vma->vm_pgoff; 1876 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; 1877 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 1878 zba = details->first_index; 1879 if (zba < vba) 1880 zba = vba; 1881 zea = details->last_index; 1882 if (zea > vea) 1883 zea = vea; 1884 1885 if (unmap_mapping_range_vma(vma, 1886 ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 1887 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 1888 details) < 0) 1889 goto restart; 1890 } 1891 } 1892 1893 static inline void unmap_mapping_range_list(struct list_head *head, 1894 struct zap_details *details) 1895 { 1896 struct vm_area_struct *vma; 1897 1898 /* 1899 * In nonlinear VMAs there is no correspondence between virtual address 1900 * offset and file offset. So we must perform an exhaustive search 1901 * across *all* the pages in each nonlinear VMA, not just the pages 1902 * whose virtual address lies outside the file truncation point. 1903 */ 1904 restart: 1905 list_for_each_entry(vma, head, shared.vm_set.list) { 1906 /* Skip quickly over those we have already dealt with */ 1907 if (vma->vm_truncate_count == details->truncate_count) 1908 continue; 1909 details->nonlinear_vma = vma; 1910 if (unmap_mapping_range_vma(vma, vma->vm_start, 1911 vma->vm_end, details) < 0) 1912 goto restart; 1913 } 1914 } 1915 1916 /** 1917 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file. 1918 * @mapping: the address space containing mmaps to be unmapped. 1919 * @holebegin: byte in first page to unmap, relative to the start of 1920 * the underlying file. This will be rounded down to a PAGE_SIZE 1921 * boundary. Note that this is different from vmtruncate(), which 1922 * must keep the partial page. In contrast, we must get rid of 1923 * partial pages. 1924 * @holelen: size of prospective hole in bytes. This will be rounded 1925 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 1926 * end of the file. 1927 * @even_cows: 1 when truncating a file, unmap even private COWed pages; 1928 * but 0 when invalidating pagecache, don't throw away private data. 1929 */ 1930 void unmap_mapping_range(struct address_space *mapping, 1931 loff_t const holebegin, loff_t const holelen, int even_cows) 1932 { 1933 struct zap_details details; 1934 pgoff_t hba = holebegin >> PAGE_SHIFT; 1935 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1936 1937 /* Check for overflow. */ 1938 if (sizeof(holelen) > sizeof(hlen)) { 1939 long long holeend = 1940 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1941 if (holeend & ~(long long)ULONG_MAX) 1942 hlen = ULONG_MAX - hba + 1; 1943 } 1944 1945 details.check_mapping = even_cows? NULL: mapping; 1946 details.nonlinear_vma = NULL; 1947 details.first_index = hba; 1948 details.last_index = hba + hlen - 1; 1949 if (details.last_index < details.first_index) 1950 details.last_index = ULONG_MAX; 1951 details.i_mmap_lock = &mapping->i_mmap_lock; 1952 1953 spin_lock(&mapping->i_mmap_lock); 1954 1955 /* serialize i_size write against truncate_count write */ 1956 smp_wmb(); 1957 /* Protect against page faults, and endless unmapping loops */ 1958 mapping->truncate_count++; 1959 /* 1960 * For archs where spin_lock has inclusive semantics like ia64 1961 * this smp_mb() will prevent to read pagetable contents 1962 * before the truncate_count increment is visible to 1963 * other cpus. 1964 */ 1965 smp_mb(); 1966 if (unlikely(is_restart_addr(mapping->truncate_count))) { 1967 if (mapping->truncate_count == 0) 1968 reset_vma_truncate_counts(mapping); 1969 mapping->truncate_count++; 1970 } 1971 details.truncate_count = mapping->truncate_count; 1972 1973 if (unlikely(!prio_tree_empty(&mapping->i_mmap))) 1974 unmap_mapping_range_tree(&mapping->i_mmap, &details); 1975 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 1976 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 1977 spin_unlock(&mapping->i_mmap_lock); 1978 } 1979 EXPORT_SYMBOL(unmap_mapping_range); 1980 1981 /** 1982 * vmtruncate - unmap mappings "freed" by truncate() syscall 1983 * @inode: inode of the file used 1984 * @offset: file offset to start truncating 1985 * 1986 * NOTE! We have to be ready to update the memory sharing 1987 * between the file and the memory map for a potential last 1988 * incomplete page. Ugly, but necessary. 1989 */ 1990 int vmtruncate(struct inode * inode, loff_t offset) 1991 { 1992 struct address_space *mapping = inode->i_mapping; 1993 unsigned long limit; 1994 1995 if (inode->i_size < offset) 1996 goto do_expand; 1997 /* 1998 * truncation of in-use swapfiles is disallowed - it would cause 1999 * subsequent swapout to scribble on the now-freed blocks. 2000 */ 2001 if (IS_SWAPFILE(inode)) 2002 goto out_busy; 2003 i_size_write(inode, offset); 2004 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 2005 truncate_inode_pages(mapping, offset); 2006 goto out_truncate; 2007 2008 do_expand: 2009 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; 2010 if (limit != RLIM_INFINITY && offset > limit) 2011 goto out_sig; 2012 if (offset > inode->i_sb->s_maxbytes) 2013 goto out_big; 2014 i_size_write(inode, offset); 2015 2016 out_truncate: 2017 if (inode->i_op && inode->i_op->truncate) 2018 inode->i_op->truncate(inode); 2019 return 0; 2020 out_sig: 2021 send_sig(SIGXFSZ, current, 0); 2022 out_big: 2023 return -EFBIG; 2024 out_busy: 2025 return -ETXTBSY; 2026 } 2027 EXPORT_SYMBOL(vmtruncate); 2028 2029 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) 2030 { 2031 struct address_space *mapping = inode->i_mapping; 2032 2033 /* 2034 * If the underlying filesystem is not going to provide 2035 * a way to truncate a range of blocks (punch a hole) - 2036 * we should return failure right now. 2037 */ 2038 if (!inode->i_op || !inode->i_op->truncate_range) 2039 return -ENOSYS; 2040 2041 mutex_lock(&inode->i_mutex); 2042 down_write(&inode->i_alloc_sem); 2043 unmap_mapping_range(mapping, offset, (end - offset), 1); 2044 truncate_inode_pages_range(mapping, offset, end); 2045 inode->i_op->truncate_range(inode, offset, end); 2046 up_write(&inode->i_alloc_sem); 2047 mutex_unlock(&inode->i_mutex); 2048 2049 return 0; 2050 } 2051 2052 /** 2053 * swapin_readahead - swap in pages in hope we need them soon 2054 * @entry: swap entry of this memory 2055 * @addr: address to start 2056 * @vma: user vma this addresses belong to 2057 * 2058 * Primitive swap readahead code. We simply read an aligned block of 2059 * (1 << page_cluster) entries in the swap area. This method is chosen 2060 * because it doesn't cost us any seek time. We also make sure to queue 2061 * the 'original' request together with the readahead ones... 2062 * 2063 * This has been extended to use the NUMA policies from the mm triggering 2064 * the readahead. 2065 * 2066 * Caller must hold down_read on the vma->vm_mm if vma is not NULL. 2067 */ 2068 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) 2069 { 2070 #ifdef CONFIG_NUMA 2071 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; 2072 #endif 2073 int i, num; 2074 struct page *new_page; 2075 unsigned long offset; 2076 2077 /* 2078 * Get the number of handles we should do readahead io to. 2079 */ 2080 num = valid_swaphandles(entry, &offset); 2081 for (i = 0; i < num; offset++, i++) { 2082 /* Ok, do the async read-ahead now */ 2083 new_page = read_swap_cache_async(swp_entry(swp_type(entry), 2084 offset), vma, addr); 2085 if (!new_page) 2086 break; 2087 page_cache_release(new_page); 2088 #ifdef CONFIG_NUMA 2089 /* 2090 * Find the next applicable VMA for the NUMA policy. 2091 */ 2092 addr += PAGE_SIZE; 2093 if (addr == 0) 2094 vma = NULL; 2095 if (vma) { 2096 if (addr >= vma->vm_end) { 2097 vma = next_vma; 2098 next_vma = vma ? vma->vm_next : NULL; 2099 } 2100 if (vma && addr < vma->vm_start) 2101 vma = NULL; 2102 } else { 2103 if (next_vma && addr >= next_vma->vm_start) { 2104 vma = next_vma; 2105 next_vma = vma->vm_next; 2106 } 2107 } 2108 #endif 2109 } 2110 lru_add_drain(); /* Push any new pages onto the LRU now */ 2111 } 2112 2113 /* 2114 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2115 * but allow concurrent faults), and pte mapped but not yet locked. 2116 * We return with mmap_sem still held, but pte unmapped and unlocked. 2117 */ 2118 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 2119 unsigned long address, pte_t *page_table, pmd_t *pmd, 2120 int write_access, pte_t orig_pte) 2121 { 2122 spinlock_t *ptl; 2123 struct page *page; 2124 swp_entry_t entry; 2125 pte_t pte; 2126 int ret = VM_FAULT_MINOR; 2127 2128 if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 2129 goto out; 2130 2131 entry = pte_to_swp_entry(orig_pte); 2132 if (is_migration_entry(entry)) { 2133 migration_entry_wait(mm, pmd, address); 2134 goto out; 2135 } 2136 delayacct_set_flag(DELAYACCT_PF_SWAPIN); 2137 page = lookup_swap_cache(entry); 2138 if (!page) { 2139 grab_swap_token(); /* Contend for token _before_ read-in */ 2140 swapin_readahead(entry, address, vma); 2141 page = read_swap_cache_async(entry, vma, address); 2142 if (!page) { 2143 /* 2144 * Back out if somebody else faulted in this pte 2145 * while we released the pte lock. 2146 */ 2147 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2148 if (likely(pte_same(*page_table, orig_pte))) 2149 ret = VM_FAULT_OOM; 2150 delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 2151 goto unlock; 2152 } 2153 2154 /* Had to read the page from swap area: Major fault */ 2155 ret = VM_FAULT_MAJOR; 2156 count_vm_event(PGMAJFAULT); 2157 } 2158 2159 delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 2160 mark_page_accessed(page); 2161 lock_page(page); 2162 2163 /* 2164 * Back out if somebody else already faulted in this pte. 2165 */ 2166 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2167 if (unlikely(!pte_same(*page_table, orig_pte))) 2168 goto out_nomap; 2169 2170 if (unlikely(!PageUptodate(page))) { 2171 ret = VM_FAULT_SIGBUS; 2172 goto out_nomap; 2173 } 2174 2175 /* The page isn't present yet, go ahead with the fault. */ 2176 2177 inc_mm_counter(mm, anon_rss); 2178 pte = mk_pte(page, vma->vm_page_prot); 2179 if (write_access && can_share_swap_page(page)) { 2180 pte = maybe_mkwrite(pte_mkdirty(pte), vma); 2181 write_access = 0; 2182 } 2183 2184 flush_icache_page(vma, page); 2185 set_pte_at(mm, address, page_table, pte); 2186 page_add_anon_rmap(page, vma, address); 2187 2188 swap_free(entry); 2189 if (vm_swap_full()) 2190 remove_exclusive_swap_page(page); 2191 unlock_page(page); 2192 2193 if (write_access) { 2194 if (do_wp_page(mm, vma, address, 2195 page_table, pmd, ptl, pte) == VM_FAULT_OOM) 2196 ret = VM_FAULT_OOM; 2197 goto out; 2198 } 2199 2200 /* No need to invalidate - it was non-present before */ 2201 update_mmu_cache(vma, address, pte); 2202 lazy_mmu_prot_update(pte); 2203 unlock: 2204 pte_unmap_unlock(page_table, ptl); 2205 out: 2206 return ret; 2207 out_nomap: 2208 pte_unmap_unlock(page_table, ptl); 2209 unlock_page(page); 2210 page_cache_release(page); 2211 return ret; 2212 } 2213 2214 /* 2215 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2216 * but allow concurrent faults), and pte mapped but not yet locked. 2217 * We return with mmap_sem still held, but pte unmapped and unlocked. 2218 */ 2219 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 2220 unsigned long address, pte_t *page_table, pmd_t *pmd, 2221 int write_access) 2222 { 2223 struct page *page; 2224 spinlock_t *ptl; 2225 pte_t entry; 2226 2227 if (write_access) { 2228 /* Allocate our own private page. */ 2229 pte_unmap(page_table); 2230 2231 if (unlikely(anon_vma_prepare(vma))) 2232 goto oom; 2233 page = alloc_zeroed_user_highpage(vma, address); 2234 if (!page) 2235 goto oom; 2236 2237 entry = mk_pte(page, vma->vm_page_prot); 2238 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2239 2240 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2241 if (!pte_none(*page_table)) 2242 goto release; 2243 inc_mm_counter(mm, anon_rss); 2244 lru_cache_add_active(page); 2245 page_add_new_anon_rmap(page, vma, address); 2246 } else { 2247 /* Map the ZERO_PAGE - vm_page_prot is readonly */ 2248 page = ZERO_PAGE(address); 2249 page_cache_get(page); 2250 entry = mk_pte(page, vma->vm_page_prot); 2251 2252 ptl = pte_lockptr(mm, pmd); 2253 spin_lock(ptl); 2254 if (!pte_none(*page_table)) 2255 goto release; 2256 inc_mm_counter(mm, file_rss); 2257 page_add_file_rmap(page); 2258 } 2259 2260 set_pte_at(mm, address, page_table, entry); 2261 2262 /* No need to invalidate - it was non-present before */ 2263 update_mmu_cache(vma, address, entry); 2264 lazy_mmu_prot_update(entry); 2265 unlock: 2266 pte_unmap_unlock(page_table, ptl); 2267 return VM_FAULT_MINOR; 2268 release: 2269 page_cache_release(page); 2270 goto unlock; 2271 oom: 2272 return VM_FAULT_OOM; 2273 } 2274 2275 /* 2276 * do_no_page() tries to create a new page mapping. It aggressively 2277 * tries to share with existing pages, but makes a separate copy if 2278 * the "write_access" parameter is true in order to avoid the next 2279 * page fault. 2280 * 2281 * As this is called only for pages that do not currently exist, we 2282 * do not need to flush old virtual caches or the TLB. 2283 * 2284 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2285 * but allow concurrent faults), and pte mapped but not yet locked. 2286 * We return with mmap_sem still held, but pte unmapped and unlocked. 2287 */ 2288 static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 2289 unsigned long address, pte_t *page_table, pmd_t *pmd, 2290 int write_access) 2291 { 2292 spinlock_t *ptl; 2293 struct page *new_page; 2294 struct address_space *mapping = NULL; 2295 pte_t entry; 2296 unsigned int sequence = 0; 2297 int ret = VM_FAULT_MINOR; 2298 int anon = 0; 2299 struct page *dirty_page = NULL; 2300 2301 pte_unmap(page_table); 2302 BUG_ON(vma->vm_flags & VM_PFNMAP); 2303 2304 if (vma->vm_file) { 2305 mapping = vma->vm_file->f_mapping; 2306 sequence = mapping->truncate_count; 2307 smp_rmb(); /* serializes i_size against truncate_count */ 2308 } 2309 retry: 2310 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); 2311 /* 2312 * No smp_rmb is needed here as long as there's a full 2313 * spin_lock/unlock sequence inside the ->nopage callback 2314 * (for the pagecache lookup) that acts as an implicit 2315 * smp_mb() and prevents the i_size read to happen 2316 * after the next truncate_count read. 2317 */ 2318 2319 /* no page was available -- either SIGBUS, OOM or REFAULT */ 2320 if (unlikely(new_page == NOPAGE_SIGBUS)) 2321 return VM_FAULT_SIGBUS; 2322 else if (unlikely(new_page == NOPAGE_OOM)) 2323 return VM_FAULT_OOM; 2324 else if (unlikely(new_page == NOPAGE_REFAULT)) 2325 return VM_FAULT_MINOR; 2326 2327 /* 2328 * Should we do an early C-O-W break? 2329 */ 2330 if (write_access) { 2331 if (!(vma->vm_flags & VM_SHARED)) { 2332 struct page *page; 2333 2334 if (unlikely(anon_vma_prepare(vma))) 2335 goto oom; 2336 page = alloc_page_vma(GFP_HIGHUSER, vma, address); 2337 if (!page) 2338 goto oom; 2339 copy_user_highpage(page, new_page, address, vma); 2340 page_cache_release(new_page); 2341 new_page = page; 2342 anon = 1; 2343 2344 } else { 2345 /* if the page will be shareable, see if the backing 2346 * address space wants to know that the page is about 2347 * to become writable */ 2348 if (vma->vm_ops->page_mkwrite && 2349 vma->vm_ops->page_mkwrite(vma, new_page) < 0 2350 ) { 2351 page_cache_release(new_page); 2352 return VM_FAULT_SIGBUS; 2353 } 2354 } 2355 } 2356 2357 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2358 /* 2359 * For a file-backed vma, someone could have truncated or otherwise 2360 * invalidated this page. If unmap_mapping_range got called, 2361 * retry getting the page. 2362 */ 2363 if (mapping && unlikely(sequence != mapping->truncate_count)) { 2364 pte_unmap_unlock(page_table, ptl); 2365 page_cache_release(new_page); 2366 cond_resched(); 2367 sequence = mapping->truncate_count; 2368 smp_rmb(); 2369 goto retry; 2370 } 2371 2372 /* 2373 * This silly early PAGE_DIRTY setting removes a race 2374 * due to the bad i386 page protection. But it's valid 2375 * for other architectures too. 2376 * 2377 * Note that if write_access is true, we either now have 2378 * an exclusive copy of the page, or this is a shared mapping, 2379 * so we can make it writable and dirty to avoid having to 2380 * handle that later. 2381 */ 2382 /* Only go through if we didn't race with anybody else... */ 2383 if (pte_none(*page_table)) { 2384 flush_icache_page(vma, new_page); 2385 entry = mk_pte(new_page, vma->vm_page_prot); 2386 if (write_access) 2387 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2388 set_pte_at(mm, address, page_table, entry); 2389 if (anon) { 2390 inc_mm_counter(mm, anon_rss); 2391 lru_cache_add_active(new_page); 2392 page_add_new_anon_rmap(new_page, vma, address); 2393 } else { 2394 inc_mm_counter(mm, file_rss); 2395 page_add_file_rmap(new_page); 2396 if (write_access) { 2397 dirty_page = new_page; 2398 get_page(dirty_page); 2399 } 2400 } 2401 } else { 2402 /* One of our sibling threads was faster, back out. */ 2403 page_cache_release(new_page); 2404 goto unlock; 2405 } 2406 2407 /* no need to invalidate: a not-present page shouldn't be cached */ 2408 update_mmu_cache(vma, address, entry); 2409 lazy_mmu_prot_update(entry); 2410 unlock: 2411 pte_unmap_unlock(page_table, ptl); 2412 if (dirty_page) { 2413 set_page_dirty_balance(dirty_page); 2414 put_page(dirty_page); 2415 } 2416 return ret; 2417 oom: 2418 page_cache_release(new_page); 2419 return VM_FAULT_OOM; 2420 } 2421 2422 /* 2423 * do_no_pfn() tries to create a new page mapping for a page without 2424 * a struct_page backing it 2425 * 2426 * As this is called only for pages that do not currently exist, we 2427 * do not need to flush old virtual caches or the TLB. 2428 * 2429 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2430 * but allow concurrent faults), and pte mapped but not yet locked. 2431 * We return with mmap_sem still held, but pte unmapped and unlocked. 2432 * 2433 * It is expected that the ->nopfn handler always returns the same pfn 2434 * for a given virtual mapping. 2435 * 2436 * Mark this `noinline' to prevent it from bloating the main pagefault code. 2437 */ 2438 static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, 2439 unsigned long address, pte_t *page_table, pmd_t *pmd, 2440 int write_access) 2441 { 2442 spinlock_t *ptl; 2443 pte_t entry; 2444 unsigned long pfn; 2445 int ret = VM_FAULT_MINOR; 2446 2447 pte_unmap(page_table); 2448 BUG_ON(!(vma->vm_flags & VM_PFNMAP)); 2449 BUG_ON(is_cow_mapping(vma->vm_flags)); 2450 2451 pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK); 2452 if (unlikely(pfn == NOPFN_OOM)) 2453 return VM_FAULT_OOM; 2454 else if (unlikely(pfn == NOPFN_SIGBUS)) 2455 return VM_FAULT_SIGBUS; 2456 else if (unlikely(pfn == NOPFN_REFAULT)) 2457 return VM_FAULT_MINOR; 2458 2459 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2460 2461 /* Only go through if we didn't race with anybody else... */ 2462 if (pte_none(*page_table)) { 2463 entry = pfn_pte(pfn, vma->vm_page_prot); 2464 if (write_access) 2465 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2466 set_pte_at(mm, address, page_table, entry); 2467 } 2468 pte_unmap_unlock(page_table, ptl); 2469 return ret; 2470 } 2471 2472 /* 2473 * Fault of a previously existing named mapping. Repopulate the pte 2474 * from the encoded file_pte if possible. This enables swappable 2475 * nonlinear vmas. 2476 * 2477 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2478 * but allow concurrent faults), and pte mapped but not yet locked. 2479 * We return with mmap_sem still held, but pte unmapped and unlocked. 2480 */ 2481 static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma, 2482 unsigned long address, pte_t *page_table, pmd_t *pmd, 2483 int write_access, pte_t orig_pte) 2484 { 2485 pgoff_t pgoff; 2486 int err; 2487 2488 if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 2489 return VM_FAULT_MINOR; 2490 2491 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { 2492 /* 2493 * Page table corrupted: show pte and kill process. 2494 */ 2495 print_bad_pte(vma, orig_pte, address); 2496 return VM_FAULT_OOM; 2497 } 2498 /* We can then assume vm->vm_ops && vma->vm_ops->populate */ 2499 2500 pgoff = pte_to_pgoff(orig_pte); 2501 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, 2502 vma->vm_page_prot, pgoff, 0); 2503 if (err == -ENOMEM) 2504 return VM_FAULT_OOM; 2505 if (err) 2506 return VM_FAULT_SIGBUS; 2507 return VM_FAULT_MAJOR; 2508 } 2509 2510 /* 2511 * These routines also need to handle stuff like marking pages dirty 2512 * and/or accessed for architectures that don't do it in hardware (most 2513 * RISC architectures). The early dirtying is also good on the i386. 2514 * 2515 * There is also a hook called "update_mmu_cache()" that architectures 2516 * with external mmu caches can use to update those (ie the Sparc or 2517 * PowerPC hashed page tables that act as extended TLBs). 2518 * 2519 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2520 * but allow concurrent faults), and pte mapped but not yet locked. 2521 * We return with mmap_sem still held, but pte unmapped and unlocked. 2522 */ 2523 static inline int handle_pte_fault(struct mm_struct *mm, 2524 struct vm_area_struct *vma, unsigned long address, 2525 pte_t *pte, pmd_t *pmd, int write_access) 2526 { 2527 pte_t entry; 2528 pte_t old_entry; 2529 spinlock_t *ptl; 2530 2531 old_entry = entry = *pte; 2532 if (!pte_present(entry)) { 2533 if (pte_none(entry)) { 2534 if (vma->vm_ops) { 2535 if (vma->vm_ops->nopage) 2536 return do_no_page(mm, vma, address, 2537 pte, pmd, 2538 write_access); 2539 if (unlikely(vma->vm_ops->nopfn)) 2540 return do_no_pfn(mm, vma, address, pte, 2541 pmd, write_access); 2542 } 2543 return do_anonymous_page(mm, vma, address, 2544 pte, pmd, write_access); 2545 } 2546 if (pte_file(entry)) 2547 return do_file_page(mm, vma, address, 2548 pte, pmd, write_access, entry); 2549 return do_swap_page(mm, vma, address, 2550 pte, pmd, write_access, entry); 2551 } 2552 2553 ptl = pte_lockptr(mm, pmd); 2554 spin_lock(ptl); 2555 if (unlikely(!pte_same(*pte, entry))) 2556 goto unlock; 2557 if (write_access) { 2558 if (!pte_write(entry)) 2559 return do_wp_page(mm, vma, address, 2560 pte, pmd, ptl, entry); 2561 entry = pte_mkdirty(entry); 2562 } 2563 entry = pte_mkyoung(entry); 2564 if (!pte_same(old_entry, entry)) { 2565 ptep_set_access_flags(vma, address, pte, entry, write_access); 2566 update_mmu_cache(vma, address, entry); 2567 lazy_mmu_prot_update(entry); 2568 } else { 2569 /* 2570 * This is needed only for protection faults but the arch code 2571 * is not yet telling us if this is a protection fault or not. 2572 * This still avoids useless tlb flushes for .text page faults 2573 * with threads. 2574 */ 2575 if (write_access) 2576 flush_tlb_page(vma, address); 2577 } 2578 unlock: 2579 pte_unmap_unlock(pte, ptl); 2580 return VM_FAULT_MINOR; 2581 } 2582 2583 /* 2584 * By the time we get here, we already hold the mm semaphore 2585 */ 2586 int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2587 unsigned long address, int write_access) 2588 { 2589 pgd_t *pgd; 2590 pud_t *pud; 2591 pmd_t *pmd; 2592 pte_t *pte; 2593 2594 __set_current_state(TASK_RUNNING); 2595 2596 count_vm_event(PGFAULT); 2597 2598 if (unlikely(is_vm_hugetlb_page(vma))) 2599 return hugetlb_fault(mm, vma, address, write_access); 2600 2601 pgd = pgd_offset(mm, address); 2602 pud = pud_alloc(mm, pgd, address); 2603 if (!pud) 2604 return VM_FAULT_OOM; 2605 pmd = pmd_alloc(mm, pud, address); 2606 if (!pmd) 2607 return VM_FAULT_OOM; 2608 pte = pte_alloc_map(mm, pmd, address); 2609 if (!pte) 2610 return VM_FAULT_OOM; 2611 2612 return handle_pte_fault(mm, vma, address, pte, pmd, write_access); 2613 } 2614 2615 EXPORT_SYMBOL_GPL(__handle_mm_fault); 2616 2617 #ifndef __PAGETABLE_PUD_FOLDED 2618 /* 2619 * Allocate page upper directory. 2620 * We've already handled the fast-path in-line. 2621 */ 2622 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 2623 { 2624 pud_t *new = pud_alloc_one(mm, address); 2625 if (!new) 2626 return -ENOMEM; 2627 2628 spin_lock(&mm->page_table_lock); 2629 if (pgd_present(*pgd)) /* Another has populated it */ 2630 pud_free(new); 2631 else 2632 pgd_populate(mm, pgd, new); 2633 spin_unlock(&mm->page_table_lock); 2634 return 0; 2635 } 2636 #endif /* __PAGETABLE_PUD_FOLDED */ 2637 2638 #ifndef __PAGETABLE_PMD_FOLDED 2639 /* 2640 * Allocate page middle directory. 2641 * We've already handled the fast-path in-line. 2642 */ 2643 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 2644 { 2645 pmd_t *new = pmd_alloc_one(mm, address); 2646 if (!new) 2647 return -ENOMEM; 2648 2649 spin_lock(&mm->page_table_lock); 2650 #ifndef __ARCH_HAS_4LEVEL_HACK 2651 if (pud_present(*pud)) /* Another has populated it */ 2652 pmd_free(new); 2653 else 2654 pud_populate(mm, pud, new); 2655 #else 2656 if (pgd_present(*pud)) /* Another has populated it */ 2657 pmd_free(new); 2658 else 2659 pgd_populate(mm, pud, new); 2660 #endif /* __ARCH_HAS_4LEVEL_HACK */ 2661 spin_unlock(&mm->page_table_lock); 2662 return 0; 2663 } 2664 #endif /* __PAGETABLE_PMD_FOLDED */ 2665 2666 int make_pages_present(unsigned long addr, unsigned long end) 2667 { 2668 int ret, len, write; 2669 struct vm_area_struct * vma; 2670 2671 vma = find_vma(current->mm, addr); 2672 if (!vma) 2673 return -1; 2674 write = (vma->vm_flags & VM_WRITE) != 0; 2675 BUG_ON(addr >= end); 2676 BUG_ON(end > vma->vm_end); 2677 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; 2678 ret = get_user_pages(current, current->mm, addr, 2679 len, write, 0, NULL, NULL); 2680 if (ret < 0) 2681 return ret; 2682 return ret == len ? 0 : -1; 2683 } 2684 2685 /* 2686 * Map a vmalloc()-space virtual address to the physical page. 2687 */ 2688 struct page * vmalloc_to_page(void * vmalloc_addr) 2689 { 2690 unsigned long addr = (unsigned long) vmalloc_addr; 2691 struct page *page = NULL; 2692 pgd_t *pgd = pgd_offset_k(addr); 2693 pud_t *pud; 2694 pmd_t *pmd; 2695 pte_t *ptep, pte; 2696 2697 if (!pgd_none(*pgd)) { 2698 pud = pud_offset(pgd, addr); 2699 if (!pud_none(*pud)) { 2700 pmd = pmd_offset(pud, addr); 2701 if (!pmd_none(*pmd)) { 2702 ptep = pte_offset_map(pmd, addr); 2703 pte = *ptep; 2704 if (pte_present(pte)) 2705 page = pte_page(pte); 2706 pte_unmap(ptep); 2707 } 2708 } 2709 } 2710 return page; 2711 } 2712 2713 EXPORT_SYMBOL(vmalloc_to_page); 2714 2715 /* 2716 * Map a vmalloc()-space virtual address to the physical page frame number. 2717 */ 2718 unsigned long vmalloc_to_pfn(void * vmalloc_addr) 2719 { 2720 return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 2721 } 2722 2723 EXPORT_SYMBOL(vmalloc_to_pfn); 2724 2725 #if !defined(__HAVE_ARCH_GATE_AREA) 2726 2727 #if defined(AT_SYSINFO_EHDR) 2728 static struct vm_area_struct gate_vma; 2729 2730 static int __init gate_vma_init(void) 2731 { 2732 gate_vma.vm_mm = NULL; 2733 gate_vma.vm_start = FIXADDR_USER_START; 2734 gate_vma.vm_end = FIXADDR_USER_END; 2735 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 2736 gate_vma.vm_page_prot = __P101; 2737 /* 2738 * Make sure the vDSO gets into every core dump. 2739 * Dumping its contents makes post-mortem fully interpretable later 2740 * without matching up the same kernel and hardware config to see 2741 * what PC values meant. 2742 */ 2743 gate_vma.vm_flags |= VM_ALWAYSDUMP; 2744 return 0; 2745 } 2746 __initcall(gate_vma_init); 2747 #endif 2748 2749 struct vm_area_struct *get_gate_vma(struct task_struct *tsk) 2750 { 2751 #ifdef AT_SYSINFO_EHDR 2752 return &gate_vma; 2753 #else 2754 return NULL; 2755 #endif 2756 } 2757 2758 int in_gate_area_no_task(unsigned long addr) 2759 { 2760 #ifdef AT_SYSINFO_EHDR 2761 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 2762 return 1; 2763 #endif 2764 return 0; 2765 } 2766 2767 #endif /* __HAVE_ARCH_GATE_AREA */ 2768 2769 /* 2770 * Access another process' address space. 2771 * Source/target buffer must be kernel space, 2772 * Do not walk the page table directly, use get_user_pages 2773 */ 2774 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) 2775 { 2776 struct mm_struct *mm; 2777 struct vm_area_struct *vma; 2778 struct page *page; 2779 void *old_buf = buf; 2780 2781 mm = get_task_mm(tsk); 2782 if (!mm) 2783 return 0; 2784 2785 down_read(&mm->mmap_sem); 2786 /* ignore errors, just check how much was sucessfully transfered */ 2787 while (len) { 2788 int bytes, ret, offset; 2789 void *maddr; 2790 2791 ret = get_user_pages(tsk, mm, addr, 1, 2792 write, 1, &page, &vma); 2793 if (ret <= 0) 2794 break; 2795 2796 bytes = len; 2797 offset = addr & (PAGE_SIZE-1); 2798 if (bytes > PAGE_SIZE-offset) 2799 bytes = PAGE_SIZE-offset; 2800 2801 maddr = kmap(page); 2802 if (write) { 2803 copy_to_user_page(vma, page, addr, 2804 maddr + offset, buf, bytes); 2805 set_page_dirty_lock(page); 2806 } else { 2807 copy_from_user_page(vma, page, addr, 2808 buf, maddr + offset, bytes); 2809 } 2810 kunmap(page); 2811 page_cache_release(page); 2812 len -= bytes; 2813 buf += bytes; 2814 addr += bytes; 2815 } 2816 up_read(&mm->mmap_sem); 2817 mmput(mm); 2818 2819 return buf - old_buf; 2820 } 2821