memory.c revision 46017e954826ac59e91df76341a3f76b45467847
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 */ 65unsigned long max_mapnr; 66struct page *mem_map; 67 68EXPORT_SYMBOL(max_mapnr); 69EXPORT_SYMBOL(mem_map); 70#endif 71 72unsigned 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 */ 80void * high_memory; 81 82EXPORT_SYMBOL(num_physpages); 83EXPORT_SYMBOL(high_memory); 84 85int randomize_va_space __read_mostly = 1; 86 87static int __init disable_randmaps(char *s) 88{ 89 randomize_va_space = 0; 90 return 1; 91} 92__setup("norandmaps", disable_randmaps); 93 94 95/* 96 * If a p?d_bad entry is found while walking page tables, report 97 * the error, before resetting entry to p?d_none. Usually (but 98 * very seldom) called out from the p?d_none_or_clear_bad macros. 99 */ 100 101void pgd_clear_bad(pgd_t *pgd) 102{ 103 pgd_ERROR(*pgd); 104 pgd_clear(pgd); 105} 106 107void pud_clear_bad(pud_t *pud) 108{ 109 pud_ERROR(*pud); 110 pud_clear(pud); 111} 112 113void pmd_clear_bad(pmd_t *pmd) 114{ 115 pmd_ERROR(*pmd); 116 pmd_clear(pmd); 117} 118 119/* 120 * Note: this doesn't free the actual pages themselves. That 121 * has been handled earlier when unmapping all the memory regions. 122 */ 123static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) 124{ 125 struct page *page = pmd_page(*pmd); 126 pmd_clear(pmd); 127 pte_lock_deinit(page); 128 pte_free_tlb(tlb, page); 129 dec_zone_page_state(page, NR_PAGETABLE); 130 tlb->mm->nr_ptes--; 131} 132 133static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 134 unsigned long addr, unsigned long end, 135 unsigned long floor, unsigned long ceiling) 136{ 137 pmd_t *pmd; 138 unsigned long next; 139 unsigned long start; 140 141 start = addr; 142 pmd = pmd_offset(pud, addr); 143 do { 144 next = pmd_addr_end(addr, end); 145 if (pmd_none_or_clear_bad(pmd)) 146 continue; 147 free_pte_range(tlb, pmd); 148 } while (pmd++, addr = next, addr != end); 149 150 start &= PUD_MASK; 151 if (start < floor) 152 return; 153 if (ceiling) { 154 ceiling &= PUD_MASK; 155 if (!ceiling) 156 return; 157 } 158 if (end - 1 > ceiling - 1) 159 return; 160 161 pmd = pmd_offset(pud, start); 162 pud_clear(pud); 163 pmd_free_tlb(tlb, pmd); 164} 165 166static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 167 unsigned long addr, unsigned long end, 168 unsigned long floor, unsigned long ceiling) 169{ 170 pud_t *pud; 171 unsigned long next; 172 unsigned long start; 173 174 start = addr; 175 pud = pud_offset(pgd, addr); 176 do { 177 next = pud_addr_end(addr, end); 178 if (pud_none_or_clear_bad(pud)) 179 continue; 180 free_pmd_range(tlb, pud, addr, next, floor, ceiling); 181 } while (pud++, addr = next, addr != end); 182 183 start &= PGDIR_MASK; 184 if (start < floor) 185 return; 186 if (ceiling) { 187 ceiling &= PGDIR_MASK; 188 if (!ceiling) 189 return; 190 } 191 if (end - 1 > ceiling - 1) 192 return; 193 194 pud = pud_offset(pgd, start); 195 pgd_clear(pgd); 196 pud_free_tlb(tlb, pud); 197} 198 199/* 200 * This function frees user-level page tables of a process. 201 * 202 * Must be called with pagetable lock held. 203 */ 204void free_pgd_range(struct mmu_gather **tlb, 205 unsigned long addr, unsigned long end, 206 unsigned long floor, unsigned long ceiling) 207{ 208 pgd_t *pgd; 209 unsigned long next; 210 unsigned long start; 211 212 /* 213 * The next few lines have given us lots of grief... 214 * 215 * Why are we testing PMD* at this top level? Because often 216 * there will be no work to do at all, and we'd prefer not to 217 * go all the way down to the bottom just to discover that. 218 * 219 * Why all these "- 1"s? Because 0 represents both the bottom 220 * of the address space and the top of it (using -1 for the 221 * top wouldn't help much: the masks would do the wrong thing). 222 * The rule is that addr 0 and floor 0 refer to the bottom of 223 * the address space, but end 0 and ceiling 0 refer to the top 224 * Comparisons need to use "end - 1" and "ceiling - 1" (though 225 * that end 0 case should be mythical). 226 * 227 * Wherever addr is brought up or ceiling brought down, we must 228 * be careful to reject "the opposite 0" before it confuses the 229 * subsequent tests. But what about where end is brought down 230 * by PMD_SIZE below? no, end can't go down to 0 there. 231 * 232 * Whereas we round start (addr) and ceiling down, by different 233 * masks at different levels, in order to test whether a table 234 * now has no other vmas using it, so can be freed, we don't 235 * bother to round floor or end up - the tests don't need that. 236 */ 237 238 addr &= PMD_MASK; 239 if (addr < floor) { 240 addr += PMD_SIZE; 241 if (!addr) 242 return; 243 } 244 if (ceiling) { 245 ceiling &= PMD_MASK; 246 if (!ceiling) 247 return; 248 } 249 if (end - 1 > ceiling - 1) 250 end -= PMD_SIZE; 251 if (addr > end - 1) 252 return; 253 254 start = addr; 255 pgd = pgd_offset((*tlb)->mm, addr); 256 do { 257 next = pgd_addr_end(addr, end); 258 if (pgd_none_or_clear_bad(pgd)) 259 continue; 260 free_pud_range(*tlb, pgd, addr, next, floor, ceiling); 261 } while (pgd++, addr = next, addr != end); 262} 263 264void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, 265 unsigned long floor, unsigned long ceiling) 266{ 267 while (vma) { 268 struct vm_area_struct *next = vma->vm_next; 269 unsigned long addr = vma->vm_start; 270 271 /* 272 * Hide vma from rmap and vmtruncate before freeing pgtables 273 */ 274 anon_vma_unlink(vma); 275 unlink_file_vma(vma); 276 277 if (is_vm_hugetlb_page(vma)) { 278 hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 279 floor, next? next->vm_start: ceiling); 280 } else { 281 /* 282 * Optimization: gather nearby vmas into one call down 283 */ 284 while (next && next->vm_start <= vma->vm_end + PMD_SIZE 285 && !is_vm_hugetlb_page(next)) { 286 vma = next; 287 next = vma->vm_next; 288 anon_vma_unlink(vma); 289 unlink_file_vma(vma); 290 } 291 free_pgd_range(tlb, addr, vma->vm_end, 292 floor, next? next->vm_start: ceiling); 293 } 294 vma = next; 295 } 296} 297 298int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) 299{ 300 struct page *new = pte_alloc_one(mm, address); 301 if (!new) 302 return -ENOMEM; 303 304 pte_lock_init(new); 305 spin_lock(&mm->page_table_lock); 306 if (pmd_present(*pmd)) { /* Another has populated it */ 307 pte_lock_deinit(new); 308 pte_free(new); 309 } else { 310 mm->nr_ptes++; 311 inc_zone_page_state(new, NR_PAGETABLE); 312 pmd_populate(mm, pmd, new); 313 } 314 spin_unlock(&mm->page_table_lock); 315 return 0; 316} 317 318int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) 319{ 320 pte_t *new = pte_alloc_one_kernel(&init_mm, address); 321 if (!new) 322 return -ENOMEM; 323 324 spin_lock(&init_mm.page_table_lock); 325 if (pmd_present(*pmd)) /* Another has populated it */ 326 pte_free_kernel(new); 327 else 328 pmd_populate_kernel(&init_mm, pmd, new); 329 spin_unlock(&init_mm.page_table_lock); 330 return 0; 331} 332 333static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) 334{ 335 if (file_rss) 336 add_mm_counter(mm, file_rss, file_rss); 337 if (anon_rss) 338 add_mm_counter(mm, anon_rss, anon_rss); 339} 340 341/* 342 * This function is called to print an error when a bad pte 343 * is found. For example, we might have a PFN-mapped pte in 344 * a region that doesn't allow it. 345 * 346 * The calling function must still handle the error. 347 */ 348void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) 349{ 350 printk(KERN_ERR "Bad pte = %08llx, process = %s, " 351 "vm_flags = %lx, vaddr = %lx\n", 352 (long long)pte_val(pte), 353 (vma->vm_mm == current->mm ? current->comm : "???"), 354 vma->vm_flags, vaddr); 355 dump_stack(); 356} 357 358static inline int is_cow_mapping(unsigned int flags) 359{ 360 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; 361} 362 363/* 364 * This function gets the "struct page" associated with a pte. 365 * 366 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping 367 * will have each page table entry just pointing to a raw page frame 368 * number, and as far as the VM layer is concerned, those do not have 369 * pages associated with them - even if the PFN might point to memory 370 * that otherwise is perfectly fine and has a "struct page". 371 * 372 * The way we recognize those mappings is through the rules set up 373 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set, 374 * and the vm_pgoff will point to the first PFN mapped: thus every 375 * page that is a raw mapping will always honor the rule 376 * 377 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) 378 * 379 * and if that isn't true, the page has been COW'ed (in which case it 380 * _does_ have a "struct page" associated with it even if it is in a 381 * VM_PFNMAP range). 382 */ 383struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte) 384{ 385 unsigned long pfn = pte_pfn(pte); 386 387 if (unlikely(vma->vm_flags & VM_PFNMAP)) { 388 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT; 389 if (pfn == vma->vm_pgoff + off) 390 return NULL; 391 if (!is_cow_mapping(vma->vm_flags)) 392 return NULL; 393 } 394 395#ifdef CONFIG_DEBUG_VM 396 /* 397 * Add some anal sanity checks for now. Eventually, 398 * we should just do "return pfn_to_page(pfn)", but 399 * in the meantime we check that we get a valid pfn, 400 * and that the resulting page looks ok. 401 */ 402 if (unlikely(!pfn_valid(pfn))) { 403 print_bad_pte(vma, pte, addr); 404 return NULL; 405 } 406#endif 407 408 /* 409 * NOTE! We still have PageReserved() pages in the page 410 * tables. 411 * 412 * The PAGE_ZERO() pages and various VDSO mappings can 413 * cause them to exist. 414 */ 415 return pfn_to_page(pfn); 416} 417 418/* 419 * copy one vm_area from one task to the other. Assumes the page tables 420 * already present in the new task to be cleared in the whole range 421 * covered by this vma. 422 */ 423 424static inline void 425copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 426 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, 427 unsigned long addr, int *rss) 428{ 429 unsigned long vm_flags = vma->vm_flags; 430 pte_t pte = *src_pte; 431 struct page *page; 432 433 /* pte contains position in swap or file, so copy. */ 434 if (unlikely(!pte_present(pte))) { 435 if (!pte_file(pte)) { 436 swp_entry_t entry = pte_to_swp_entry(pte); 437 438 swap_duplicate(entry); 439 /* make sure dst_mm is on swapoff's mmlist. */ 440 if (unlikely(list_empty(&dst_mm->mmlist))) { 441 spin_lock(&mmlist_lock); 442 if (list_empty(&dst_mm->mmlist)) 443 list_add(&dst_mm->mmlist, 444 &src_mm->mmlist); 445 spin_unlock(&mmlist_lock); 446 } 447 if (is_write_migration_entry(entry) && 448 is_cow_mapping(vm_flags)) { 449 /* 450 * COW mappings require pages in both parent 451 * and child to be set to read. 452 */ 453 make_migration_entry_read(&entry); 454 pte = swp_entry_to_pte(entry); 455 set_pte_at(src_mm, addr, src_pte, pte); 456 } 457 } 458 goto out_set_pte; 459 } 460 461 /* 462 * If it's a COW mapping, write protect it both 463 * in the parent and the child 464 */ 465 if (is_cow_mapping(vm_flags)) { 466 ptep_set_wrprotect(src_mm, addr, src_pte); 467 pte = pte_wrprotect(pte); 468 } 469 470 /* 471 * If it's a shared mapping, mark it clean in 472 * the child 473 */ 474 if (vm_flags & VM_SHARED) 475 pte = pte_mkclean(pte); 476 pte = pte_mkold(pte); 477 478 page = vm_normal_page(vma, addr, pte); 479 if (page) { 480 get_page(page); 481 page_dup_rmap(page, vma, addr); 482 rss[!!PageAnon(page)]++; 483 } 484 485out_set_pte: 486 set_pte_at(dst_mm, addr, dst_pte, pte); 487} 488 489static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 490 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 491 unsigned long addr, unsigned long end) 492{ 493 pte_t *src_pte, *dst_pte; 494 spinlock_t *src_ptl, *dst_ptl; 495 int progress = 0; 496 int rss[2]; 497 498again: 499 rss[1] = rss[0] = 0; 500 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); 501 if (!dst_pte) 502 return -ENOMEM; 503 src_pte = pte_offset_map_nested(src_pmd, addr); 504 src_ptl = pte_lockptr(src_mm, src_pmd); 505 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); 506 arch_enter_lazy_mmu_mode(); 507 508 do { 509 /* 510 * We are holding two locks at this point - either of them 511 * could generate latencies in another task on another CPU. 512 */ 513 if (progress >= 32) { 514 progress = 0; 515 if (need_resched() || 516 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) 517 break; 518 } 519 if (pte_none(*src_pte)) { 520 progress++; 521 continue; 522 } 523 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); 524 progress += 8; 525 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 526 527 arch_leave_lazy_mmu_mode(); 528 spin_unlock(src_ptl); 529 pte_unmap_nested(src_pte - 1); 530 add_mm_rss(dst_mm, rss[0], rss[1]); 531 pte_unmap_unlock(dst_pte - 1, dst_ptl); 532 cond_resched(); 533 if (addr != end) 534 goto again; 535 return 0; 536} 537 538static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 539 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 540 unsigned long addr, unsigned long end) 541{ 542 pmd_t *src_pmd, *dst_pmd; 543 unsigned long next; 544 545 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 546 if (!dst_pmd) 547 return -ENOMEM; 548 src_pmd = pmd_offset(src_pud, addr); 549 do { 550 next = pmd_addr_end(addr, end); 551 if (pmd_none_or_clear_bad(src_pmd)) 552 continue; 553 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 554 vma, addr, next)) 555 return -ENOMEM; 556 } while (dst_pmd++, src_pmd++, addr = next, addr != end); 557 return 0; 558} 559 560static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 561 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 562 unsigned long addr, unsigned long end) 563{ 564 pud_t *src_pud, *dst_pud; 565 unsigned long next; 566 567 dst_pud = pud_alloc(dst_mm, dst_pgd, addr); 568 if (!dst_pud) 569 return -ENOMEM; 570 src_pud = pud_offset(src_pgd, addr); 571 do { 572 next = pud_addr_end(addr, end); 573 if (pud_none_or_clear_bad(src_pud)) 574 continue; 575 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 576 vma, addr, next)) 577 return -ENOMEM; 578 } while (dst_pud++, src_pud++, addr = next, addr != end); 579 return 0; 580} 581 582int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 583 struct vm_area_struct *vma) 584{ 585 pgd_t *src_pgd, *dst_pgd; 586 unsigned long next; 587 unsigned long addr = vma->vm_start; 588 unsigned long end = vma->vm_end; 589 590 /* 591 * Don't copy ptes where a page fault will fill them correctly. 592 * Fork becomes much lighter when there are big shared or private 593 * readonly mappings. The tradeoff is that copy_page_range is more 594 * efficient than faulting. 595 */ 596 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { 597 if (!vma->anon_vma) 598 return 0; 599 } 600 601 if (is_vm_hugetlb_page(vma)) 602 return copy_hugetlb_page_range(dst_mm, src_mm, vma); 603 604 dst_pgd = pgd_offset(dst_mm, addr); 605 src_pgd = pgd_offset(src_mm, addr); 606 do { 607 next = pgd_addr_end(addr, end); 608 if (pgd_none_or_clear_bad(src_pgd)) 609 continue; 610 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, 611 vma, addr, next)) 612 return -ENOMEM; 613 } while (dst_pgd++, src_pgd++, addr = next, addr != end); 614 return 0; 615} 616 617static unsigned long zap_pte_range(struct mmu_gather *tlb, 618 struct vm_area_struct *vma, pmd_t *pmd, 619 unsigned long addr, unsigned long end, 620 long *zap_work, struct zap_details *details) 621{ 622 struct mm_struct *mm = tlb->mm; 623 pte_t *pte; 624 spinlock_t *ptl; 625 int file_rss = 0; 626 int anon_rss = 0; 627 628 pte = pte_offset_map_lock(mm, pmd, addr, &ptl); 629 arch_enter_lazy_mmu_mode(); 630 do { 631 pte_t ptent = *pte; 632 if (pte_none(ptent)) { 633 (*zap_work)--; 634 continue; 635 } 636 637 (*zap_work) -= PAGE_SIZE; 638 639 if (pte_present(ptent)) { 640 struct page *page; 641 642 page = vm_normal_page(vma, addr, ptent); 643 if (unlikely(details) && page) { 644 /* 645 * unmap_shared_mapping_pages() wants to 646 * invalidate cache without truncating: 647 * unmap shared but keep private pages. 648 */ 649 if (details->check_mapping && 650 details->check_mapping != page->mapping) 651 continue; 652 /* 653 * Each page->index must be checked when 654 * invalidating or truncating nonlinear. 655 */ 656 if (details->nonlinear_vma && 657 (page->index < details->first_index || 658 page->index > details->last_index)) 659 continue; 660 } 661 ptent = ptep_get_and_clear_full(mm, addr, pte, 662 tlb->fullmm); 663 tlb_remove_tlb_entry(tlb, pte, addr); 664 if (unlikely(!page)) 665 continue; 666 if (unlikely(details) && details->nonlinear_vma 667 && linear_page_index(details->nonlinear_vma, 668 addr) != page->index) 669 set_pte_at(mm, addr, pte, 670 pgoff_to_pte(page->index)); 671 if (PageAnon(page)) 672 anon_rss--; 673 else { 674 if (pte_dirty(ptent)) 675 set_page_dirty(page); 676 if (pte_young(ptent)) 677 SetPageReferenced(page); 678 file_rss--; 679 } 680 page_remove_rmap(page, vma); 681 tlb_remove_page(tlb, page); 682 continue; 683 } 684 /* 685 * If details->check_mapping, we leave swap entries; 686 * if details->nonlinear_vma, we leave file entries. 687 */ 688 if (unlikely(details)) 689 continue; 690 if (!pte_file(ptent)) 691 free_swap_and_cache(pte_to_swp_entry(ptent)); 692 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); 693 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); 694 695 add_mm_rss(mm, file_rss, anon_rss); 696 arch_leave_lazy_mmu_mode(); 697 pte_unmap_unlock(pte - 1, ptl); 698 699 return addr; 700} 701 702static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, 703 struct vm_area_struct *vma, pud_t *pud, 704 unsigned long addr, unsigned long end, 705 long *zap_work, struct zap_details *details) 706{ 707 pmd_t *pmd; 708 unsigned long next; 709 710 pmd = pmd_offset(pud, addr); 711 do { 712 next = pmd_addr_end(addr, end); 713 if (pmd_none_or_clear_bad(pmd)) { 714 (*zap_work)--; 715 continue; 716 } 717 next = zap_pte_range(tlb, vma, pmd, addr, next, 718 zap_work, details); 719 } while (pmd++, addr = next, (addr != end && *zap_work > 0)); 720 721 return addr; 722} 723 724static inline unsigned long zap_pud_range(struct mmu_gather *tlb, 725 struct vm_area_struct *vma, pgd_t *pgd, 726 unsigned long addr, unsigned long end, 727 long *zap_work, struct zap_details *details) 728{ 729 pud_t *pud; 730 unsigned long next; 731 732 pud = pud_offset(pgd, addr); 733 do { 734 next = pud_addr_end(addr, end); 735 if (pud_none_or_clear_bad(pud)) { 736 (*zap_work)--; 737 continue; 738 } 739 next = zap_pmd_range(tlb, vma, pud, addr, next, 740 zap_work, details); 741 } while (pud++, addr = next, (addr != end && *zap_work > 0)); 742 743 return addr; 744} 745 746static unsigned long unmap_page_range(struct mmu_gather *tlb, 747 struct vm_area_struct *vma, 748 unsigned long addr, unsigned long end, 749 long *zap_work, struct zap_details *details) 750{ 751 pgd_t *pgd; 752 unsigned long next; 753 754 if (details && !details->check_mapping && !details->nonlinear_vma) 755 details = NULL; 756 757 BUG_ON(addr >= end); 758 tlb_start_vma(tlb, vma); 759 pgd = pgd_offset(vma->vm_mm, addr); 760 do { 761 next = pgd_addr_end(addr, end); 762 if (pgd_none_or_clear_bad(pgd)) { 763 (*zap_work)--; 764 continue; 765 } 766 next = zap_pud_range(tlb, vma, pgd, addr, next, 767 zap_work, details); 768 } while (pgd++, addr = next, (addr != end && *zap_work > 0)); 769 tlb_end_vma(tlb, vma); 770 771 return addr; 772} 773 774#ifdef CONFIG_PREEMPT 775# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) 776#else 777/* No preempt: go for improved straight-line efficiency */ 778# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) 779#endif 780 781/** 782 * unmap_vmas - unmap a range of memory covered by a list of vma's 783 * @tlbp: address of the caller's struct mmu_gather 784 * @vma: the starting vma 785 * @start_addr: virtual address at which to start unmapping 786 * @end_addr: virtual address at which to end unmapping 787 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here 788 * @details: details of nonlinear truncation or shared cache invalidation 789 * 790 * Returns the end address of the unmapping (restart addr if interrupted). 791 * 792 * Unmap all pages in the vma list. 793 * 794 * We aim to not hold locks for too long (for scheduling latency reasons). 795 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to 796 * return the ending mmu_gather to the caller. 797 * 798 * Only addresses between `start' and `end' will be unmapped. 799 * 800 * The VMA list must be sorted in ascending virtual address order. 801 * 802 * unmap_vmas() assumes that the caller will flush the whole unmapped address 803 * range after unmap_vmas() returns. So the only responsibility here is to 804 * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 805 * drops the lock and schedules. 806 */ 807unsigned long unmap_vmas(struct mmu_gather **tlbp, 808 struct vm_area_struct *vma, unsigned long start_addr, 809 unsigned long end_addr, unsigned long *nr_accounted, 810 struct zap_details *details) 811{ 812 long zap_work = ZAP_BLOCK_SIZE; 813 unsigned long tlb_start = 0; /* For tlb_finish_mmu */ 814 int tlb_start_valid = 0; 815 unsigned long start = start_addr; 816 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; 817 int fullmm = (*tlbp)->fullmm; 818 819 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { 820 unsigned long end; 821 822 start = max(vma->vm_start, start_addr); 823 if (start >= vma->vm_end) 824 continue; 825 end = min(vma->vm_end, end_addr); 826 if (end <= vma->vm_start) 827 continue; 828 829 if (vma->vm_flags & VM_ACCOUNT) 830 *nr_accounted += (end - start) >> PAGE_SHIFT; 831 832 while (start != end) { 833 if (!tlb_start_valid) { 834 tlb_start = start; 835 tlb_start_valid = 1; 836 } 837 838 if (unlikely(is_vm_hugetlb_page(vma))) { 839 unmap_hugepage_range(vma, start, end); 840 zap_work -= (end - start) / 841 (HPAGE_SIZE / PAGE_SIZE); 842 start = end; 843 } else 844 start = unmap_page_range(*tlbp, vma, 845 start, end, &zap_work, details); 846 847 if (zap_work > 0) { 848 BUG_ON(start != end); 849 break; 850 } 851 852 tlb_finish_mmu(*tlbp, tlb_start, start); 853 854 if (need_resched() || 855 (i_mmap_lock && spin_needbreak(i_mmap_lock))) { 856 if (i_mmap_lock) { 857 *tlbp = NULL; 858 goto out; 859 } 860 cond_resched(); 861 } 862 863 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); 864 tlb_start_valid = 0; 865 zap_work = ZAP_BLOCK_SIZE; 866 } 867 } 868out: 869 return start; /* which is now the end (or restart) address */ 870} 871 872/** 873 * zap_page_range - remove user pages in a given range 874 * @vma: vm_area_struct holding the applicable pages 875 * @address: starting address of pages to zap 876 * @size: number of bytes to zap 877 * @details: details of nonlinear truncation or shared cache invalidation 878 */ 879unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, 880 unsigned long size, struct zap_details *details) 881{ 882 struct mm_struct *mm = vma->vm_mm; 883 struct mmu_gather *tlb; 884 unsigned long end = address + size; 885 unsigned long nr_accounted = 0; 886 887 lru_add_drain(); 888 tlb = tlb_gather_mmu(mm, 0); 889 update_hiwater_rss(mm); 890 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); 891 if (tlb) 892 tlb_finish_mmu(tlb, address, end); 893 return end; 894} 895 896/* 897 * Do a quick page-table lookup for a single page. 898 */ 899struct page *follow_page(struct vm_area_struct *vma, unsigned long address, 900 unsigned int flags) 901{ 902 pgd_t *pgd; 903 pud_t *pud; 904 pmd_t *pmd; 905 pte_t *ptep, pte; 906 spinlock_t *ptl; 907 struct page *page; 908 struct mm_struct *mm = vma->vm_mm; 909 910 page = follow_huge_addr(mm, address, flags & FOLL_WRITE); 911 if (!IS_ERR(page)) { 912 BUG_ON(flags & FOLL_GET); 913 goto out; 914 } 915 916 page = NULL; 917 pgd = pgd_offset(mm, address); 918 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 919 goto no_page_table; 920 921 pud = pud_offset(pgd, address); 922 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 923 goto no_page_table; 924 925 pmd = pmd_offset(pud, address); 926 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 927 goto no_page_table; 928 929 if (pmd_huge(*pmd)) { 930 BUG_ON(flags & FOLL_GET); 931 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); 932 goto out; 933 } 934 935 ptep = pte_offset_map_lock(mm, pmd, address, &ptl); 936 if (!ptep) 937 goto out; 938 939 pte = *ptep; 940 if (!pte_present(pte)) 941 goto unlock; 942 if ((flags & FOLL_WRITE) && !pte_write(pte)) 943 goto unlock; 944 page = vm_normal_page(vma, address, pte); 945 if (unlikely(!page)) 946 goto unlock; 947 948 if (flags & FOLL_GET) 949 get_page(page); 950 if (flags & FOLL_TOUCH) { 951 if ((flags & FOLL_WRITE) && 952 !pte_dirty(pte) && !PageDirty(page)) 953 set_page_dirty(page); 954 mark_page_accessed(page); 955 } 956unlock: 957 pte_unmap_unlock(ptep, ptl); 958out: 959 return page; 960 961no_page_table: 962 /* 963 * When core dumping an enormous anonymous area that nobody 964 * has touched so far, we don't want to allocate page tables. 965 */ 966 if (flags & FOLL_ANON) { 967 page = ZERO_PAGE(0); 968 if (flags & FOLL_GET) 969 get_page(page); 970 BUG_ON(flags & FOLL_WRITE); 971 } 972 return page; 973} 974 975int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 976 unsigned long start, int len, int write, int force, 977 struct page **pages, struct vm_area_struct **vmas) 978{ 979 int i; 980 unsigned int vm_flags; 981 982 /* 983 * Require read or write permissions. 984 * If 'force' is set, we only require the "MAY" flags. 985 */ 986 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 987 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 988 i = 0; 989 990 do { 991 struct vm_area_struct *vma; 992 unsigned int foll_flags; 993 994 vma = find_extend_vma(mm, start); 995 if (!vma && in_gate_area(tsk, start)) { 996 unsigned long pg = start & PAGE_MASK; 997 struct vm_area_struct *gate_vma = get_gate_vma(tsk); 998 pgd_t *pgd; 999 pud_t *pud; 1000 pmd_t *pmd; 1001 pte_t *pte; 1002 if (write) /* user gate pages are read-only */ 1003 return i ? : -EFAULT; 1004 if (pg > TASK_SIZE) 1005 pgd = pgd_offset_k(pg); 1006 else 1007 pgd = pgd_offset_gate(mm, pg); 1008 BUG_ON(pgd_none(*pgd)); 1009 pud = pud_offset(pgd, pg); 1010 BUG_ON(pud_none(*pud)); 1011 pmd = pmd_offset(pud, pg); 1012 if (pmd_none(*pmd)) 1013 return i ? : -EFAULT; 1014 pte = pte_offset_map(pmd, pg); 1015 if (pte_none(*pte)) { 1016 pte_unmap(pte); 1017 return i ? : -EFAULT; 1018 } 1019 if (pages) { 1020 struct page *page = vm_normal_page(gate_vma, start, *pte); 1021 pages[i] = page; 1022 if (page) 1023 get_page(page); 1024 } 1025 pte_unmap(pte); 1026 if (vmas) 1027 vmas[i] = gate_vma; 1028 i++; 1029 start += PAGE_SIZE; 1030 len--; 1031 continue; 1032 } 1033 1034 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) 1035 || !(vm_flags & vma->vm_flags)) 1036 return i ? : -EFAULT; 1037 1038 if (is_vm_hugetlb_page(vma)) { 1039 i = follow_hugetlb_page(mm, vma, pages, vmas, 1040 &start, &len, i, write); 1041 continue; 1042 } 1043 1044 foll_flags = FOLL_TOUCH; 1045 if (pages) 1046 foll_flags |= FOLL_GET; 1047 if (!write && !(vma->vm_flags & VM_LOCKED) && 1048 (!vma->vm_ops || (!vma->vm_ops->nopage && 1049 !vma->vm_ops->fault))) 1050 foll_flags |= FOLL_ANON; 1051 1052 do { 1053 struct page *page; 1054 1055 /* 1056 * If tsk is ooming, cut off its access to large memory 1057 * allocations. It has a pending SIGKILL, but it can't 1058 * be processed until returning to user space. 1059 */ 1060 if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE))) 1061 return -ENOMEM; 1062 1063 if (write) 1064 foll_flags |= FOLL_WRITE; 1065 1066 cond_resched(); 1067 while (!(page = follow_page(vma, start, foll_flags))) { 1068 int ret; 1069 ret = handle_mm_fault(mm, vma, start, 1070 foll_flags & FOLL_WRITE); 1071 if (ret & VM_FAULT_ERROR) { 1072 if (ret & VM_FAULT_OOM) 1073 return i ? i : -ENOMEM; 1074 else if (ret & VM_FAULT_SIGBUS) 1075 return i ? i : -EFAULT; 1076 BUG(); 1077 } 1078 if (ret & VM_FAULT_MAJOR) 1079 tsk->maj_flt++; 1080 else 1081 tsk->min_flt++; 1082 1083 /* 1084 * The VM_FAULT_WRITE bit tells us that 1085 * do_wp_page has broken COW when necessary, 1086 * even if maybe_mkwrite decided not to set 1087 * pte_write. We can thus safely do subsequent 1088 * page lookups as if they were reads. 1089 */ 1090 if (ret & VM_FAULT_WRITE) 1091 foll_flags &= ~FOLL_WRITE; 1092 1093 cond_resched(); 1094 } 1095 if (pages) { 1096 pages[i] = page; 1097 1098 flush_anon_page(vma, page, start); 1099 flush_dcache_page(page); 1100 } 1101 if (vmas) 1102 vmas[i] = vma; 1103 i++; 1104 start += PAGE_SIZE; 1105 len--; 1106 } while (len && start < vma->vm_end); 1107 } while (len); 1108 return i; 1109} 1110EXPORT_SYMBOL(get_user_pages); 1111 1112pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl) 1113{ 1114 pgd_t * pgd = pgd_offset(mm, addr); 1115 pud_t * pud = pud_alloc(mm, pgd, addr); 1116 if (pud) { 1117 pmd_t * pmd = pmd_alloc(mm, pud, addr); 1118 if (pmd) 1119 return pte_alloc_map_lock(mm, pmd, addr, ptl); 1120 } 1121 return NULL; 1122} 1123 1124/* 1125 * This is the old fallback for page remapping. 1126 * 1127 * For historical reasons, it only allows reserved pages. Only 1128 * old drivers should use this, and they needed to mark their 1129 * pages reserved for the old functions anyway. 1130 */ 1131static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot) 1132{ 1133 int retval; 1134 pte_t *pte; 1135 spinlock_t *ptl; 1136 1137 retval = -EINVAL; 1138 if (PageAnon(page)) 1139 goto out; 1140 retval = -ENOMEM; 1141 flush_dcache_page(page); 1142 pte = get_locked_pte(mm, addr, &ptl); 1143 if (!pte) 1144 goto out; 1145 retval = -EBUSY; 1146 if (!pte_none(*pte)) 1147 goto out_unlock; 1148 1149 /* Ok, finally just insert the thing.. */ 1150 get_page(page); 1151 inc_mm_counter(mm, file_rss); 1152 page_add_file_rmap(page); 1153 set_pte_at(mm, addr, pte, mk_pte(page, prot)); 1154 1155 retval = 0; 1156out_unlock: 1157 pte_unmap_unlock(pte, ptl); 1158out: 1159 return retval; 1160} 1161 1162/** 1163 * vm_insert_page - insert single page into user vma 1164 * @vma: user vma to map to 1165 * @addr: target user address of this page 1166 * @page: source kernel page 1167 * 1168 * This allows drivers to insert individual pages they've allocated 1169 * into a user vma. 1170 * 1171 * The page has to be a nice clean _individual_ kernel allocation. 1172 * If you allocate a compound page, you need to have marked it as 1173 * such (__GFP_COMP), or manually just split the page up yourself 1174 * (see split_page()). 1175 * 1176 * NOTE! Traditionally this was done with "remap_pfn_range()" which 1177 * took an arbitrary page protection parameter. This doesn't allow 1178 * that. Your vma protection will have to be set up correctly, which 1179 * means that if you want a shared writable mapping, you'd better 1180 * ask for a shared writable mapping! 1181 * 1182 * The page does not need to be reserved. 1183 */ 1184int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) 1185{ 1186 if (addr < vma->vm_start || addr >= vma->vm_end) 1187 return -EFAULT; 1188 if (!page_count(page)) 1189 return -EINVAL; 1190 vma->vm_flags |= VM_INSERTPAGE; 1191 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot); 1192} 1193EXPORT_SYMBOL(vm_insert_page); 1194 1195/** 1196 * vm_insert_pfn - insert single pfn into user vma 1197 * @vma: user vma to map to 1198 * @addr: target user address of this page 1199 * @pfn: source kernel pfn 1200 * 1201 * Similar to vm_inert_page, this allows drivers to insert individual pages 1202 * they've allocated into a user vma. Same comments apply. 1203 * 1204 * This function should only be called from a vm_ops->fault handler, and 1205 * in that case the handler should return NULL. 1206 */ 1207int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, 1208 unsigned long pfn) 1209{ 1210 struct mm_struct *mm = vma->vm_mm; 1211 int retval; 1212 pte_t *pte, entry; 1213 spinlock_t *ptl; 1214 1215 BUG_ON(!(vma->vm_flags & VM_PFNMAP)); 1216 BUG_ON(is_cow_mapping(vma->vm_flags)); 1217 1218 retval = -ENOMEM; 1219 pte = get_locked_pte(mm, addr, &ptl); 1220 if (!pte) 1221 goto out; 1222 retval = -EBUSY; 1223 if (!pte_none(*pte)) 1224 goto out_unlock; 1225 1226 /* Ok, finally just insert the thing.. */ 1227 entry = pfn_pte(pfn, vma->vm_page_prot); 1228 set_pte_at(mm, addr, pte, entry); 1229 update_mmu_cache(vma, addr, entry); 1230 1231 retval = 0; 1232out_unlock: 1233 pte_unmap_unlock(pte, ptl); 1234 1235out: 1236 return retval; 1237} 1238EXPORT_SYMBOL(vm_insert_pfn); 1239 1240/* 1241 * maps a range of physical memory into the requested pages. the old 1242 * mappings are removed. any references to nonexistent pages results 1243 * in null mappings (currently treated as "copy-on-access") 1244 */ 1245static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1246 unsigned long addr, unsigned long end, 1247 unsigned long pfn, pgprot_t prot) 1248{ 1249 pte_t *pte; 1250 spinlock_t *ptl; 1251 1252 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); 1253 if (!pte) 1254 return -ENOMEM; 1255 arch_enter_lazy_mmu_mode(); 1256 do { 1257 BUG_ON(!pte_none(*pte)); 1258 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); 1259 pfn++; 1260 } while (pte++, addr += PAGE_SIZE, addr != end); 1261 arch_leave_lazy_mmu_mode(); 1262 pte_unmap_unlock(pte - 1, ptl); 1263 return 0; 1264} 1265 1266static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 1267 unsigned long addr, unsigned long end, 1268 unsigned long pfn, pgprot_t prot) 1269{ 1270 pmd_t *pmd; 1271 unsigned long next; 1272 1273 pfn -= addr >> PAGE_SHIFT; 1274 pmd = pmd_alloc(mm, pud, addr); 1275 if (!pmd) 1276 return -ENOMEM; 1277 do { 1278 next = pmd_addr_end(addr, end); 1279 if (remap_pte_range(mm, pmd, addr, next, 1280 pfn + (addr >> PAGE_SHIFT), prot)) 1281 return -ENOMEM; 1282 } while (pmd++, addr = next, addr != end); 1283 return 0; 1284} 1285 1286static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1287 unsigned long addr, unsigned long end, 1288 unsigned long pfn, pgprot_t prot) 1289{ 1290 pud_t *pud; 1291 unsigned long next; 1292 1293 pfn -= addr >> PAGE_SHIFT; 1294 pud = pud_alloc(mm, pgd, addr); 1295 if (!pud) 1296 return -ENOMEM; 1297 do { 1298 next = pud_addr_end(addr, end); 1299 if (remap_pmd_range(mm, pud, addr, next, 1300 pfn + (addr >> PAGE_SHIFT), prot)) 1301 return -ENOMEM; 1302 } while (pud++, addr = next, addr != end); 1303 return 0; 1304} 1305 1306/** 1307 * remap_pfn_range - remap kernel memory to userspace 1308 * @vma: user vma to map to 1309 * @addr: target user address to start at 1310 * @pfn: physical address of kernel memory 1311 * @size: size of map area 1312 * @prot: page protection flags for this mapping 1313 * 1314 * Note: this is only safe if the mm semaphore is held when called. 1315 */ 1316int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 1317 unsigned long pfn, unsigned long size, pgprot_t prot) 1318{ 1319 pgd_t *pgd; 1320 unsigned long next; 1321 unsigned long end = addr + PAGE_ALIGN(size); 1322 struct mm_struct *mm = vma->vm_mm; 1323 int err; 1324 1325 /* 1326 * Physically remapped pages are special. Tell the 1327 * rest of the world about it: 1328 * VM_IO tells people not to look at these pages 1329 * (accesses can have side effects). 1330 * VM_RESERVED is specified all over the place, because 1331 * in 2.4 it kept swapout's vma scan off this vma; but 1332 * in 2.6 the LRU scan won't even find its pages, so this 1333 * flag means no more than count its pages in reserved_vm, 1334 * and omit it from core dump, even when VM_IO turned off. 1335 * VM_PFNMAP tells the core MM that the base pages are just 1336 * raw PFN mappings, and do not have a "struct page" associated 1337 * with them. 1338 * 1339 * There's a horrible special case to handle copy-on-write 1340 * behaviour that some programs depend on. We mark the "original" 1341 * un-COW'ed pages by matching them up with "vma->vm_pgoff". 1342 */ 1343 if (is_cow_mapping(vma->vm_flags)) { 1344 if (addr != vma->vm_start || end != vma->vm_end) 1345 return -EINVAL; 1346 vma->vm_pgoff = pfn; 1347 } 1348 1349 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; 1350 1351 BUG_ON(addr >= end); 1352 pfn -= addr >> PAGE_SHIFT; 1353 pgd = pgd_offset(mm, addr); 1354 flush_cache_range(vma, addr, end); 1355 do { 1356 next = pgd_addr_end(addr, end); 1357 err = remap_pud_range(mm, pgd, addr, next, 1358 pfn + (addr >> PAGE_SHIFT), prot); 1359 if (err) 1360 break; 1361 } while (pgd++, addr = next, addr != end); 1362 return err; 1363} 1364EXPORT_SYMBOL(remap_pfn_range); 1365 1366static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, 1367 unsigned long addr, unsigned long end, 1368 pte_fn_t fn, void *data) 1369{ 1370 pte_t *pte; 1371 int err; 1372 struct page *pmd_page; 1373 spinlock_t *uninitialized_var(ptl); 1374 1375 pte = (mm == &init_mm) ? 1376 pte_alloc_kernel(pmd, addr) : 1377 pte_alloc_map_lock(mm, pmd, addr, &ptl); 1378 if (!pte) 1379 return -ENOMEM; 1380 1381 BUG_ON(pmd_huge(*pmd)); 1382 1383 pmd_page = pmd_page(*pmd); 1384 1385 do { 1386 err = fn(pte, pmd_page, addr, data); 1387 if (err) 1388 break; 1389 } while (pte++, addr += PAGE_SIZE, addr != end); 1390 1391 if (mm != &init_mm) 1392 pte_unmap_unlock(pte-1, ptl); 1393 return err; 1394} 1395 1396static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, 1397 unsigned long addr, unsigned long end, 1398 pte_fn_t fn, void *data) 1399{ 1400 pmd_t *pmd; 1401 unsigned long next; 1402 int err; 1403 1404 pmd = pmd_alloc(mm, pud, addr); 1405 if (!pmd) 1406 return -ENOMEM; 1407 do { 1408 next = pmd_addr_end(addr, end); 1409 err = apply_to_pte_range(mm, pmd, addr, next, fn, data); 1410 if (err) 1411 break; 1412 } while (pmd++, addr = next, addr != end); 1413 return err; 1414} 1415 1416static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, 1417 unsigned long addr, unsigned long end, 1418 pte_fn_t fn, void *data) 1419{ 1420 pud_t *pud; 1421 unsigned long next; 1422 int err; 1423 1424 pud = pud_alloc(mm, pgd, addr); 1425 if (!pud) 1426 return -ENOMEM; 1427 do { 1428 next = pud_addr_end(addr, end); 1429 err = apply_to_pmd_range(mm, pud, addr, next, fn, data); 1430 if (err) 1431 break; 1432 } while (pud++, addr = next, addr != end); 1433 return err; 1434} 1435 1436/* 1437 * Scan a region of virtual memory, filling in page tables as necessary 1438 * and calling a provided function on each leaf page table. 1439 */ 1440int apply_to_page_range(struct mm_struct *mm, unsigned long addr, 1441 unsigned long size, pte_fn_t fn, void *data) 1442{ 1443 pgd_t *pgd; 1444 unsigned long next; 1445 unsigned long end = addr + size; 1446 int err; 1447 1448 BUG_ON(addr >= end); 1449 pgd = pgd_offset(mm, addr); 1450 do { 1451 next = pgd_addr_end(addr, end); 1452 err = apply_to_pud_range(mm, pgd, addr, next, fn, data); 1453 if (err) 1454 break; 1455 } while (pgd++, addr = next, addr != end); 1456 return err; 1457} 1458EXPORT_SYMBOL_GPL(apply_to_page_range); 1459 1460/* 1461 * handle_pte_fault chooses page fault handler according to an entry 1462 * which was read non-atomically. Before making any commitment, on 1463 * those architectures or configurations (e.g. i386 with PAE) which 1464 * might give a mix of unmatched parts, do_swap_page and do_file_page 1465 * must check under lock before unmapping the pte and proceeding 1466 * (but do_wp_page is only called after already making such a check; 1467 * and do_anonymous_page and do_no_page can safely check later on). 1468 */ 1469static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, 1470 pte_t *page_table, pte_t orig_pte) 1471{ 1472 int same = 1; 1473#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) 1474 if (sizeof(pte_t) > sizeof(unsigned long)) { 1475 spinlock_t *ptl = pte_lockptr(mm, pmd); 1476 spin_lock(ptl); 1477 same = pte_same(*page_table, orig_pte); 1478 spin_unlock(ptl); 1479 } 1480#endif 1481 pte_unmap(page_table); 1482 return same; 1483} 1484 1485/* 1486 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when 1487 * servicing faults for write access. In the normal case, do always want 1488 * pte_mkwrite. But get_user_pages can cause write faults for mappings 1489 * that do not have writing enabled, when used by access_process_vm. 1490 */ 1491static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 1492{ 1493 if (likely(vma->vm_flags & VM_WRITE)) 1494 pte = pte_mkwrite(pte); 1495 return pte; 1496} 1497 1498static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) 1499{ 1500 /* 1501 * If the source page was a PFN mapping, we don't have 1502 * a "struct page" for it. We do a best-effort copy by 1503 * just copying from the original user address. If that 1504 * fails, we just zero-fill it. Live with it. 1505 */ 1506 if (unlikely(!src)) { 1507 void *kaddr = kmap_atomic(dst, KM_USER0); 1508 void __user *uaddr = (void __user *)(va & PAGE_MASK); 1509 1510 /* 1511 * This really shouldn't fail, because the page is there 1512 * in the page tables. But it might just be unreadable, 1513 * in which case we just give up and fill the result with 1514 * zeroes. 1515 */ 1516 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) 1517 memset(kaddr, 0, PAGE_SIZE); 1518 kunmap_atomic(kaddr, KM_USER0); 1519 flush_dcache_page(dst); 1520 return; 1521 1522 } 1523 copy_user_highpage(dst, src, va, vma); 1524} 1525 1526/* 1527 * This routine handles present pages, when users try to write 1528 * to a shared page. It is done by copying the page to a new address 1529 * and decrementing the shared-page counter for the old page. 1530 * 1531 * Note that this routine assumes that the protection checks have been 1532 * done by the caller (the low-level page fault routine in most cases). 1533 * Thus we can safely just mark it writable once we've done any necessary 1534 * COW. 1535 * 1536 * We also mark the page dirty at this point even though the page will 1537 * change only once the write actually happens. This avoids a few races, 1538 * and potentially makes it more efficient. 1539 * 1540 * We enter with non-exclusive mmap_sem (to exclude vma changes, 1541 * but allow concurrent faults), with pte both mapped and locked. 1542 * We return with mmap_sem still held, but pte unmapped and unlocked. 1543 */ 1544static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 1545 unsigned long address, pte_t *page_table, pmd_t *pmd, 1546 spinlock_t *ptl, pte_t orig_pte) 1547{ 1548 struct page *old_page, *new_page; 1549 pte_t entry; 1550 int reuse = 0, ret = 0; 1551 int page_mkwrite = 0; 1552 struct page *dirty_page = NULL; 1553 1554 old_page = vm_normal_page(vma, address, orig_pte); 1555 if (!old_page) 1556 goto gotten; 1557 1558 /* 1559 * Take out anonymous pages first, anonymous shared vmas are 1560 * not dirty accountable. 1561 */ 1562 if (PageAnon(old_page)) { 1563 if (!TestSetPageLocked(old_page)) { 1564 reuse = can_share_swap_page(old_page); 1565 unlock_page(old_page); 1566 } 1567 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == 1568 (VM_WRITE|VM_SHARED))) { 1569 /* 1570 * Only catch write-faults on shared writable pages, 1571 * read-only shared pages can get COWed by 1572 * get_user_pages(.write=1, .force=1). 1573 */ 1574 if (vma->vm_ops && vma->vm_ops->page_mkwrite) { 1575 /* 1576 * Notify the address space that the page is about to 1577 * become writable so that it can prohibit this or wait 1578 * for the page to get into an appropriate state. 1579 * 1580 * We do this without the lock held, so that it can 1581 * sleep if it needs to. 1582 */ 1583 page_cache_get(old_page); 1584 pte_unmap_unlock(page_table, ptl); 1585 1586 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0) 1587 goto unwritable_page; 1588 1589 /* 1590 * Since we dropped the lock we need to revalidate 1591 * the PTE as someone else may have changed it. If 1592 * they did, we just return, as we can count on the 1593 * MMU to tell us if they didn't also make it writable. 1594 */ 1595 page_table = pte_offset_map_lock(mm, pmd, address, 1596 &ptl); 1597 page_cache_release(old_page); 1598 if (!pte_same(*page_table, orig_pte)) 1599 goto unlock; 1600 1601 page_mkwrite = 1; 1602 } 1603 dirty_page = old_page; 1604 get_page(dirty_page); 1605 reuse = 1; 1606 } 1607 1608 if (reuse) { 1609 flush_cache_page(vma, address, pte_pfn(orig_pte)); 1610 entry = pte_mkyoung(orig_pte); 1611 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1612 if (ptep_set_access_flags(vma, address, page_table, entry,1)) 1613 update_mmu_cache(vma, address, entry); 1614 ret |= VM_FAULT_WRITE; 1615 goto unlock; 1616 } 1617 1618 /* 1619 * Ok, we need to copy. Oh, well.. 1620 */ 1621 page_cache_get(old_page); 1622gotten: 1623 pte_unmap_unlock(page_table, ptl); 1624 1625 if (unlikely(anon_vma_prepare(vma))) 1626 goto oom; 1627 VM_BUG_ON(old_page == ZERO_PAGE(0)); 1628 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); 1629 if (!new_page) 1630 goto oom; 1631 cow_user_page(new_page, old_page, address, vma); 1632 1633 /* 1634 * Re-check the pte - we dropped the lock 1635 */ 1636 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 1637 if (likely(pte_same(*page_table, orig_pte))) { 1638 if (old_page) { 1639 page_remove_rmap(old_page, vma); 1640 if (!PageAnon(old_page)) { 1641 dec_mm_counter(mm, file_rss); 1642 inc_mm_counter(mm, anon_rss); 1643 } 1644 } else 1645 inc_mm_counter(mm, anon_rss); 1646 flush_cache_page(vma, address, pte_pfn(orig_pte)); 1647 entry = mk_pte(new_page, vma->vm_page_prot); 1648 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1649 /* 1650 * Clear the pte entry and flush it first, before updating the 1651 * pte with the new entry. This will avoid a race condition 1652 * seen in the presence of one thread doing SMC and another 1653 * thread doing COW. 1654 */ 1655 ptep_clear_flush(vma, address, page_table); 1656 set_pte_at(mm, address, page_table, entry); 1657 update_mmu_cache(vma, address, entry); 1658 lru_cache_add_active(new_page); 1659 page_add_new_anon_rmap(new_page, vma, address); 1660 1661 /* Free the old page.. */ 1662 new_page = old_page; 1663 ret |= VM_FAULT_WRITE; 1664 } 1665 if (new_page) 1666 page_cache_release(new_page); 1667 if (old_page) 1668 page_cache_release(old_page); 1669unlock: 1670 pte_unmap_unlock(page_table, ptl); 1671 if (dirty_page) { 1672 if (vma->vm_file) 1673 file_update_time(vma->vm_file); 1674 1675 /* 1676 * Yes, Virginia, this is actually required to prevent a race 1677 * with clear_page_dirty_for_io() from clearing the page dirty 1678 * bit after it clear all dirty ptes, but before a racing 1679 * do_wp_page installs a dirty pte. 1680 * 1681 * do_no_page is protected similarly. 1682 */ 1683 wait_on_page_locked(dirty_page); 1684 set_page_dirty_balance(dirty_page, page_mkwrite); 1685 put_page(dirty_page); 1686 } 1687 return ret; 1688oom: 1689 if (old_page) 1690 page_cache_release(old_page); 1691 return VM_FAULT_OOM; 1692 1693unwritable_page: 1694 page_cache_release(old_page); 1695 return VM_FAULT_SIGBUS; 1696} 1697 1698/* 1699 * Helper functions for unmap_mapping_range(). 1700 * 1701 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ 1702 * 1703 * We have to restart searching the prio_tree whenever we drop the lock, 1704 * since the iterator is only valid while the lock is held, and anyway 1705 * a later vma might be split and reinserted earlier while lock dropped. 1706 * 1707 * The list of nonlinear vmas could be handled more efficiently, using 1708 * a placeholder, but handle it in the same way until a need is shown. 1709 * It is important to search the prio_tree before nonlinear list: a vma 1710 * may become nonlinear and be shifted from prio_tree to nonlinear list 1711 * while the lock is dropped; but never shifted from list to prio_tree. 1712 * 1713 * In order to make forward progress despite restarting the search, 1714 * vm_truncate_count is used to mark a vma as now dealt with, so we can 1715 * quickly skip it next time around. Since the prio_tree search only 1716 * shows us those vmas affected by unmapping the range in question, we 1717 * can't efficiently keep all vmas in step with mapping->truncate_count: 1718 * so instead reset them all whenever it wraps back to 0 (then go to 1). 1719 * mapping->truncate_count and vma->vm_truncate_count are protected by 1720 * i_mmap_lock. 1721 * 1722 * In order to make forward progress despite repeatedly restarting some 1723 * large vma, note the restart_addr from unmap_vmas when it breaks out: 1724 * and restart from that address when we reach that vma again. It might 1725 * have been split or merged, shrunk or extended, but never shifted: so 1726 * restart_addr remains valid so long as it remains in the vma's range. 1727 * unmap_mapping_range forces truncate_count to leap over page-aligned 1728 * values so we can save vma's restart_addr in its truncate_count field. 1729 */ 1730#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) 1731 1732static void reset_vma_truncate_counts(struct address_space *mapping) 1733{ 1734 struct vm_area_struct *vma; 1735 struct prio_tree_iter iter; 1736 1737 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) 1738 vma->vm_truncate_count = 0; 1739 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) 1740 vma->vm_truncate_count = 0; 1741} 1742 1743static int unmap_mapping_range_vma(struct vm_area_struct *vma, 1744 unsigned long start_addr, unsigned long end_addr, 1745 struct zap_details *details) 1746{ 1747 unsigned long restart_addr; 1748 int need_break; 1749 1750 /* 1751 * files that support invalidating or truncating portions of the 1752 * file from under mmaped areas must have their ->fault function 1753 * return a locked page (and set VM_FAULT_LOCKED in the return). 1754 * This provides synchronisation against concurrent unmapping here. 1755 */ 1756 1757again: 1758 restart_addr = vma->vm_truncate_count; 1759 if (is_restart_addr(restart_addr) && start_addr < restart_addr) { 1760 start_addr = restart_addr; 1761 if (start_addr >= end_addr) { 1762 /* Top of vma has been split off since last time */ 1763 vma->vm_truncate_count = details->truncate_count; 1764 return 0; 1765 } 1766 } 1767 1768 restart_addr = zap_page_range(vma, start_addr, 1769 end_addr - start_addr, details); 1770 need_break = need_resched() || spin_needbreak(details->i_mmap_lock); 1771 1772 if (restart_addr >= end_addr) { 1773 /* We have now completed this vma: mark it so */ 1774 vma->vm_truncate_count = details->truncate_count; 1775 if (!need_break) 1776 return 0; 1777 } else { 1778 /* Note restart_addr in vma's truncate_count field */ 1779 vma->vm_truncate_count = restart_addr; 1780 if (!need_break) 1781 goto again; 1782 } 1783 1784 spin_unlock(details->i_mmap_lock); 1785 cond_resched(); 1786 spin_lock(details->i_mmap_lock); 1787 return -EINTR; 1788} 1789 1790static inline void unmap_mapping_range_tree(struct prio_tree_root *root, 1791 struct zap_details *details) 1792{ 1793 struct vm_area_struct *vma; 1794 struct prio_tree_iter iter; 1795 pgoff_t vba, vea, zba, zea; 1796 1797restart: 1798 vma_prio_tree_foreach(vma, &iter, root, 1799 details->first_index, details->last_index) { 1800 /* Skip quickly over those we have already dealt with */ 1801 if (vma->vm_truncate_count == details->truncate_count) 1802 continue; 1803 1804 vba = vma->vm_pgoff; 1805 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; 1806 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 1807 zba = details->first_index; 1808 if (zba < vba) 1809 zba = vba; 1810 zea = details->last_index; 1811 if (zea > vea) 1812 zea = vea; 1813 1814 if (unmap_mapping_range_vma(vma, 1815 ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 1816 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 1817 details) < 0) 1818 goto restart; 1819 } 1820} 1821 1822static inline void unmap_mapping_range_list(struct list_head *head, 1823 struct zap_details *details) 1824{ 1825 struct vm_area_struct *vma; 1826 1827 /* 1828 * In nonlinear VMAs there is no correspondence between virtual address 1829 * offset and file offset. So we must perform an exhaustive search 1830 * across *all* the pages in each nonlinear VMA, not just the pages 1831 * whose virtual address lies outside the file truncation point. 1832 */ 1833restart: 1834 list_for_each_entry(vma, head, shared.vm_set.list) { 1835 /* Skip quickly over those we have already dealt with */ 1836 if (vma->vm_truncate_count == details->truncate_count) 1837 continue; 1838 details->nonlinear_vma = vma; 1839 if (unmap_mapping_range_vma(vma, vma->vm_start, 1840 vma->vm_end, details) < 0) 1841 goto restart; 1842 } 1843} 1844 1845/** 1846 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file. 1847 * @mapping: the address space containing mmaps to be unmapped. 1848 * @holebegin: byte in first page to unmap, relative to the start of 1849 * the underlying file. This will be rounded down to a PAGE_SIZE 1850 * boundary. Note that this is different from vmtruncate(), which 1851 * must keep the partial page. In contrast, we must get rid of 1852 * partial pages. 1853 * @holelen: size of prospective hole in bytes. This will be rounded 1854 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 1855 * end of the file. 1856 * @even_cows: 1 when truncating a file, unmap even private COWed pages; 1857 * but 0 when invalidating pagecache, don't throw away private data. 1858 */ 1859void unmap_mapping_range(struct address_space *mapping, 1860 loff_t const holebegin, loff_t const holelen, int even_cows) 1861{ 1862 struct zap_details details; 1863 pgoff_t hba = holebegin >> PAGE_SHIFT; 1864 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1865 1866 /* Check for overflow. */ 1867 if (sizeof(holelen) > sizeof(hlen)) { 1868 long long holeend = 1869 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1870 if (holeend & ~(long long)ULONG_MAX) 1871 hlen = ULONG_MAX - hba + 1; 1872 } 1873 1874 details.check_mapping = even_cows? NULL: mapping; 1875 details.nonlinear_vma = NULL; 1876 details.first_index = hba; 1877 details.last_index = hba + hlen - 1; 1878 if (details.last_index < details.first_index) 1879 details.last_index = ULONG_MAX; 1880 details.i_mmap_lock = &mapping->i_mmap_lock; 1881 1882 spin_lock(&mapping->i_mmap_lock); 1883 1884 /* Protect against endless unmapping loops */ 1885 mapping->truncate_count++; 1886 if (unlikely(is_restart_addr(mapping->truncate_count))) { 1887 if (mapping->truncate_count == 0) 1888 reset_vma_truncate_counts(mapping); 1889 mapping->truncate_count++; 1890 } 1891 details.truncate_count = mapping->truncate_count; 1892 1893 if (unlikely(!prio_tree_empty(&mapping->i_mmap))) 1894 unmap_mapping_range_tree(&mapping->i_mmap, &details); 1895 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 1896 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 1897 spin_unlock(&mapping->i_mmap_lock); 1898} 1899EXPORT_SYMBOL(unmap_mapping_range); 1900 1901/** 1902 * vmtruncate - unmap mappings "freed" by truncate() syscall 1903 * @inode: inode of the file used 1904 * @offset: file offset to start truncating 1905 * 1906 * NOTE! We have to be ready to update the memory sharing 1907 * between the file and the memory map for a potential last 1908 * incomplete page. Ugly, but necessary. 1909 */ 1910int vmtruncate(struct inode * inode, loff_t offset) 1911{ 1912 struct address_space *mapping = inode->i_mapping; 1913 unsigned long limit; 1914 1915 if (inode->i_size < offset) 1916 goto do_expand; 1917 /* 1918 * truncation of in-use swapfiles is disallowed - it would cause 1919 * subsequent swapout to scribble on the now-freed blocks. 1920 */ 1921 if (IS_SWAPFILE(inode)) 1922 goto out_busy; 1923 i_size_write(inode, offset); 1924 1925 /* 1926 * unmap_mapping_range is called twice, first simply for efficiency 1927 * so that truncate_inode_pages does fewer single-page unmaps. However 1928 * after this first call, and before truncate_inode_pages finishes, 1929 * it is possible for private pages to be COWed, which remain after 1930 * truncate_inode_pages finishes, hence the second unmap_mapping_range 1931 * call must be made for correctness. 1932 */ 1933 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 1934 truncate_inode_pages(mapping, offset); 1935 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 1936 goto out_truncate; 1937 1938do_expand: 1939 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; 1940 if (limit != RLIM_INFINITY && offset > limit) 1941 goto out_sig; 1942 if (offset > inode->i_sb->s_maxbytes) 1943 goto out_big; 1944 i_size_write(inode, offset); 1945 1946out_truncate: 1947 if (inode->i_op && inode->i_op->truncate) 1948 inode->i_op->truncate(inode); 1949 return 0; 1950out_sig: 1951 send_sig(SIGXFSZ, current, 0); 1952out_big: 1953 return -EFBIG; 1954out_busy: 1955 return -ETXTBSY; 1956} 1957EXPORT_SYMBOL(vmtruncate); 1958 1959int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) 1960{ 1961 struct address_space *mapping = inode->i_mapping; 1962 1963 /* 1964 * If the underlying filesystem is not going to provide 1965 * a way to truncate a range of blocks (punch a hole) - 1966 * we should return failure right now. 1967 */ 1968 if (!inode->i_op || !inode->i_op->truncate_range) 1969 return -ENOSYS; 1970 1971 mutex_lock(&inode->i_mutex); 1972 down_write(&inode->i_alloc_sem); 1973 unmap_mapping_range(mapping, offset, (end - offset), 1); 1974 truncate_inode_pages_range(mapping, offset, end); 1975 unmap_mapping_range(mapping, offset, (end - offset), 1); 1976 inode->i_op->truncate_range(inode, offset, end); 1977 up_write(&inode->i_alloc_sem); 1978 mutex_unlock(&inode->i_mutex); 1979 1980 return 0; 1981} 1982 1983/* 1984 * We enter with non-exclusive mmap_sem (to exclude vma changes, 1985 * but allow concurrent faults), and pte mapped but not yet locked. 1986 * We return with mmap_sem still held, but pte unmapped and unlocked. 1987 */ 1988static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 1989 unsigned long address, pte_t *page_table, pmd_t *pmd, 1990 int write_access, pte_t orig_pte) 1991{ 1992 spinlock_t *ptl; 1993 struct page *page; 1994 swp_entry_t entry; 1995 pte_t pte; 1996 int ret = 0; 1997 1998 if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 1999 goto out; 2000 2001 entry = pte_to_swp_entry(orig_pte); 2002 if (is_migration_entry(entry)) { 2003 migration_entry_wait(mm, pmd, address); 2004 goto out; 2005 } 2006 delayacct_set_flag(DELAYACCT_PF_SWAPIN); 2007 page = lookup_swap_cache(entry); 2008 if (!page) { 2009 grab_swap_token(); /* Contend for token _before_ read-in */ 2010 page = swapin_readahead(entry, vma, address); 2011 if (!page) { 2012 /* 2013 * Back out if somebody else faulted in this pte 2014 * while we released the pte lock. 2015 */ 2016 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2017 if (likely(pte_same(*page_table, orig_pte))) 2018 ret = VM_FAULT_OOM; 2019 delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 2020 goto unlock; 2021 } 2022 2023 /* Had to read the page from swap area: Major fault */ 2024 ret = VM_FAULT_MAJOR; 2025 count_vm_event(PGMAJFAULT); 2026 } 2027 2028 mark_page_accessed(page); 2029 lock_page(page); 2030 delayacct_clear_flag(DELAYACCT_PF_SWAPIN); 2031 2032 /* 2033 * Back out if somebody else already faulted in this pte. 2034 */ 2035 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2036 if (unlikely(!pte_same(*page_table, orig_pte))) 2037 goto out_nomap; 2038 2039 if (unlikely(!PageUptodate(page))) { 2040 ret = VM_FAULT_SIGBUS; 2041 goto out_nomap; 2042 } 2043 2044 /* The page isn't present yet, go ahead with the fault. */ 2045 2046 inc_mm_counter(mm, anon_rss); 2047 pte = mk_pte(page, vma->vm_page_prot); 2048 if (write_access && can_share_swap_page(page)) { 2049 pte = maybe_mkwrite(pte_mkdirty(pte), vma); 2050 write_access = 0; 2051 } 2052 2053 flush_icache_page(vma, page); 2054 set_pte_at(mm, address, page_table, pte); 2055 page_add_anon_rmap(page, vma, address); 2056 2057 swap_free(entry); 2058 if (vm_swap_full()) 2059 remove_exclusive_swap_page(page); 2060 unlock_page(page); 2061 2062 if (write_access) { 2063 /* XXX: We could OR the do_wp_page code with this one? */ 2064 if (do_wp_page(mm, vma, address, 2065 page_table, pmd, ptl, pte) & VM_FAULT_OOM) 2066 ret = VM_FAULT_OOM; 2067 goto out; 2068 } 2069 2070 /* No need to invalidate - it was non-present before */ 2071 update_mmu_cache(vma, address, pte); 2072unlock: 2073 pte_unmap_unlock(page_table, ptl); 2074out: 2075 return ret; 2076out_nomap: 2077 pte_unmap_unlock(page_table, ptl); 2078 unlock_page(page); 2079 page_cache_release(page); 2080 return ret; 2081} 2082 2083/* 2084 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2085 * but allow concurrent faults), and pte mapped but not yet locked. 2086 * We return with mmap_sem still held, but pte unmapped and unlocked. 2087 */ 2088static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 2089 unsigned long address, pte_t *page_table, pmd_t *pmd, 2090 int write_access) 2091{ 2092 struct page *page; 2093 spinlock_t *ptl; 2094 pte_t entry; 2095 2096 /* Allocate our own private page. */ 2097 pte_unmap(page_table); 2098 2099 if (unlikely(anon_vma_prepare(vma))) 2100 goto oom; 2101 page = alloc_zeroed_user_highpage_movable(vma, address); 2102 if (!page) 2103 goto oom; 2104 2105 entry = mk_pte(page, vma->vm_page_prot); 2106 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2107 2108 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2109 if (!pte_none(*page_table)) 2110 goto release; 2111 inc_mm_counter(mm, anon_rss); 2112 lru_cache_add_active(page); 2113 page_add_new_anon_rmap(page, vma, address); 2114 set_pte_at(mm, address, page_table, entry); 2115 2116 /* No need to invalidate - it was non-present before */ 2117 update_mmu_cache(vma, address, entry); 2118unlock: 2119 pte_unmap_unlock(page_table, ptl); 2120 return 0; 2121release: 2122 page_cache_release(page); 2123 goto unlock; 2124oom: 2125 return VM_FAULT_OOM; 2126} 2127 2128/* 2129 * __do_fault() tries to create a new page mapping. It aggressively 2130 * tries to share with existing pages, but makes a separate copy if 2131 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid 2132 * the next page fault. 2133 * 2134 * As this is called only for pages that do not currently exist, we 2135 * do not need to flush old virtual caches or the TLB. 2136 * 2137 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2138 * but allow concurrent faults), and pte neither mapped nor locked. 2139 * We return with mmap_sem still held, but pte unmapped and unlocked. 2140 */ 2141static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2142 unsigned long address, pmd_t *pmd, 2143 pgoff_t pgoff, unsigned int flags, pte_t orig_pte) 2144{ 2145 pte_t *page_table; 2146 spinlock_t *ptl; 2147 struct page *page; 2148 pte_t entry; 2149 int anon = 0; 2150 struct page *dirty_page = NULL; 2151 struct vm_fault vmf; 2152 int ret; 2153 int page_mkwrite = 0; 2154 2155 vmf.virtual_address = (void __user *)(address & PAGE_MASK); 2156 vmf.pgoff = pgoff; 2157 vmf.flags = flags; 2158 vmf.page = NULL; 2159 2160 BUG_ON(vma->vm_flags & VM_PFNMAP); 2161 2162 if (likely(vma->vm_ops->fault)) { 2163 ret = vma->vm_ops->fault(vma, &vmf); 2164 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) 2165 return ret; 2166 } else { 2167 /* Legacy ->nopage path */ 2168 ret = 0; 2169 vmf.page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); 2170 /* no page was available -- either SIGBUS or OOM */ 2171 if (unlikely(vmf.page == NOPAGE_SIGBUS)) 2172 return VM_FAULT_SIGBUS; 2173 else if (unlikely(vmf.page == NOPAGE_OOM)) 2174 return VM_FAULT_OOM; 2175 } 2176 2177 /* 2178 * For consistency in subsequent calls, make the faulted page always 2179 * locked. 2180 */ 2181 if (unlikely(!(ret & VM_FAULT_LOCKED))) 2182 lock_page(vmf.page); 2183 else 2184 VM_BUG_ON(!PageLocked(vmf.page)); 2185 2186 /* 2187 * Should we do an early C-O-W break? 2188 */ 2189 page = vmf.page; 2190 if (flags & FAULT_FLAG_WRITE) { 2191 if (!(vma->vm_flags & VM_SHARED)) { 2192 anon = 1; 2193 if (unlikely(anon_vma_prepare(vma))) { 2194 ret = VM_FAULT_OOM; 2195 goto out; 2196 } 2197 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, 2198 vma, address); 2199 if (!page) { 2200 ret = VM_FAULT_OOM; 2201 goto out; 2202 } 2203 copy_user_highpage(page, vmf.page, address, vma); 2204 } else { 2205 /* 2206 * If the page will be shareable, see if the backing 2207 * address space wants to know that the page is about 2208 * to become writable 2209 */ 2210 if (vma->vm_ops->page_mkwrite) { 2211 unlock_page(page); 2212 if (vma->vm_ops->page_mkwrite(vma, page) < 0) { 2213 ret = VM_FAULT_SIGBUS; 2214 anon = 1; /* no anon but release vmf.page */ 2215 goto out_unlocked; 2216 } 2217 lock_page(page); 2218 /* 2219 * XXX: this is not quite right (racy vs 2220 * invalidate) to unlock and relock the page 2221 * like this, however a better fix requires 2222 * reworking page_mkwrite locking API, which 2223 * is better done later. 2224 */ 2225 if (!page->mapping) { 2226 ret = 0; 2227 anon = 1; /* no anon but release vmf.page */ 2228 goto out; 2229 } 2230 page_mkwrite = 1; 2231 } 2232 } 2233 2234 } 2235 2236 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2237 2238 /* 2239 * This silly early PAGE_DIRTY setting removes a race 2240 * due to the bad i386 page protection. But it's valid 2241 * for other architectures too. 2242 * 2243 * Note that if write_access is true, we either now have 2244 * an exclusive copy of the page, or this is a shared mapping, 2245 * so we can make it writable and dirty to avoid having to 2246 * handle that later. 2247 */ 2248 /* Only go through if we didn't race with anybody else... */ 2249 if (likely(pte_same(*page_table, orig_pte))) { 2250 flush_icache_page(vma, page); 2251 entry = mk_pte(page, vma->vm_page_prot); 2252 if (flags & FAULT_FLAG_WRITE) 2253 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2254 set_pte_at(mm, address, page_table, entry); 2255 if (anon) { 2256 inc_mm_counter(mm, anon_rss); 2257 lru_cache_add_active(page); 2258 page_add_new_anon_rmap(page, vma, address); 2259 } else { 2260 inc_mm_counter(mm, file_rss); 2261 page_add_file_rmap(page); 2262 if (flags & FAULT_FLAG_WRITE) { 2263 dirty_page = page; 2264 get_page(dirty_page); 2265 } 2266 } 2267 2268 /* no need to invalidate: a not-present page won't be cached */ 2269 update_mmu_cache(vma, address, entry); 2270 } else { 2271 if (anon) 2272 page_cache_release(page); 2273 else 2274 anon = 1; /* no anon but release faulted_page */ 2275 } 2276 2277 pte_unmap_unlock(page_table, ptl); 2278 2279out: 2280 unlock_page(vmf.page); 2281out_unlocked: 2282 if (anon) 2283 page_cache_release(vmf.page); 2284 else if (dirty_page) { 2285 if (vma->vm_file) 2286 file_update_time(vma->vm_file); 2287 2288 set_page_dirty_balance(dirty_page, page_mkwrite); 2289 put_page(dirty_page); 2290 } 2291 2292 return ret; 2293} 2294 2295static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2296 unsigned long address, pte_t *page_table, pmd_t *pmd, 2297 int write_access, pte_t orig_pte) 2298{ 2299 pgoff_t pgoff = (((address & PAGE_MASK) 2300 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; 2301 unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0); 2302 2303 pte_unmap(page_table); 2304 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); 2305} 2306 2307 2308/* 2309 * do_no_pfn() tries to create a new page mapping for a page without 2310 * a struct_page backing it 2311 * 2312 * As this is called only for pages that do not currently exist, we 2313 * do not need to flush old virtual caches or the TLB. 2314 * 2315 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2316 * but allow concurrent faults), and pte mapped but not yet locked. 2317 * We return with mmap_sem still held, but pte unmapped and unlocked. 2318 * 2319 * It is expected that the ->nopfn handler always returns the same pfn 2320 * for a given virtual mapping. 2321 * 2322 * Mark this `noinline' to prevent it from bloating the main pagefault code. 2323 */ 2324static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, 2325 unsigned long address, pte_t *page_table, pmd_t *pmd, 2326 int write_access) 2327{ 2328 spinlock_t *ptl; 2329 pte_t entry; 2330 unsigned long pfn; 2331 2332 pte_unmap(page_table); 2333 BUG_ON(!(vma->vm_flags & VM_PFNMAP)); 2334 BUG_ON(is_cow_mapping(vma->vm_flags)); 2335 2336 pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK); 2337 if (unlikely(pfn == NOPFN_OOM)) 2338 return VM_FAULT_OOM; 2339 else if (unlikely(pfn == NOPFN_SIGBUS)) 2340 return VM_FAULT_SIGBUS; 2341 else if (unlikely(pfn == NOPFN_REFAULT)) 2342 return 0; 2343 2344 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 2345 2346 /* Only go through if we didn't race with anybody else... */ 2347 if (pte_none(*page_table)) { 2348 entry = pfn_pte(pfn, vma->vm_page_prot); 2349 if (write_access) 2350 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 2351 set_pte_at(mm, address, page_table, entry); 2352 } 2353 pte_unmap_unlock(page_table, ptl); 2354 return 0; 2355} 2356 2357/* 2358 * Fault of a previously existing named mapping. Repopulate the pte 2359 * from the encoded file_pte if possible. This enables swappable 2360 * nonlinear vmas. 2361 * 2362 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2363 * but allow concurrent faults), and pte mapped but not yet locked. 2364 * We return with mmap_sem still held, but pte unmapped and unlocked. 2365 */ 2366static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2367 unsigned long address, pte_t *page_table, pmd_t *pmd, 2368 int write_access, pte_t orig_pte) 2369{ 2370 unsigned int flags = FAULT_FLAG_NONLINEAR | 2371 (write_access ? FAULT_FLAG_WRITE : 0); 2372 pgoff_t pgoff; 2373 2374 if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) 2375 return 0; 2376 2377 if (unlikely(!(vma->vm_flags & VM_NONLINEAR) || 2378 !(vma->vm_flags & VM_CAN_NONLINEAR))) { 2379 /* 2380 * Page table corrupted: show pte and kill process. 2381 */ 2382 print_bad_pte(vma, orig_pte, address); 2383 return VM_FAULT_OOM; 2384 } 2385 2386 pgoff = pte_to_pgoff(orig_pte); 2387 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); 2388} 2389 2390/* 2391 * These routines also need to handle stuff like marking pages dirty 2392 * and/or accessed for architectures that don't do it in hardware (most 2393 * RISC architectures). The early dirtying is also good on the i386. 2394 * 2395 * There is also a hook called "update_mmu_cache()" that architectures 2396 * with external mmu caches can use to update those (ie the Sparc or 2397 * PowerPC hashed page tables that act as extended TLBs). 2398 * 2399 * We enter with non-exclusive mmap_sem (to exclude vma changes, 2400 * but allow concurrent faults), and pte mapped but not yet locked. 2401 * We return with mmap_sem still held, but pte unmapped and unlocked. 2402 */ 2403static inline int handle_pte_fault(struct mm_struct *mm, 2404 struct vm_area_struct *vma, unsigned long address, 2405 pte_t *pte, pmd_t *pmd, int write_access) 2406{ 2407 pte_t entry; 2408 spinlock_t *ptl; 2409 2410 entry = *pte; 2411 if (!pte_present(entry)) { 2412 if (pte_none(entry)) { 2413 if (vma->vm_ops) { 2414 if (vma->vm_ops->fault || vma->vm_ops->nopage) 2415 return do_linear_fault(mm, vma, address, 2416 pte, pmd, write_access, entry); 2417 if (unlikely(vma->vm_ops->nopfn)) 2418 return do_no_pfn(mm, vma, address, pte, 2419 pmd, write_access); 2420 } 2421 return do_anonymous_page(mm, vma, address, 2422 pte, pmd, write_access); 2423 } 2424 if (pte_file(entry)) 2425 return do_nonlinear_fault(mm, vma, address, 2426 pte, pmd, write_access, entry); 2427 return do_swap_page(mm, vma, address, 2428 pte, pmd, write_access, entry); 2429 } 2430 2431 ptl = pte_lockptr(mm, pmd); 2432 spin_lock(ptl); 2433 if (unlikely(!pte_same(*pte, entry))) 2434 goto unlock; 2435 if (write_access) { 2436 if (!pte_write(entry)) 2437 return do_wp_page(mm, vma, address, 2438 pte, pmd, ptl, entry); 2439 entry = pte_mkdirty(entry); 2440 } 2441 entry = pte_mkyoung(entry); 2442 if (ptep_set_access_flags(vma, address, pte, entry, write_access)) { 2443 update_mmu_cache(vma, address, entry); 2444 } else { 2445 /* 2446 * This is needed only for protection faults but the arch code 2447 * is not yet telling us if this is a protection fault or not. 2448 * This still avoids useless tlb flushes for .text page faults 2449 * with threads. 2450 */ 2451 if (write_access) 2452 flush_tlb_page(vma, address); 2453 } 2454unlock: 2455 pte_unmap_unlock(pte, ptl); 2456 return 0; 2457} 2458 2459/* 2460 * By the time we get here, we already hold the mm semaphore 2461 */ 2462int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2463 unsigned long address, int write_access) 2464{ 2465 pgd_t *pgd; 2466 pud_t *pud; 2467 pmd_t *pmd; 2468 pte_t *pte; 2469 2470 __set_current_state(TASK_RUNNING); 2471 2472 count_vm_event(PGFAULT); 2473 2474 if (unlikely(is_vm_hugetlb_page(vma))) 2475 return hugetlb_fault(mm, vma, address, write_access); 2476 2477 pgd = pgd_offset(mm, address); 2478 pud = pud_alloc(mm, pgd, address); 2479 if (!pud) 2480 return VM_FAULT_OOM; 2481 pmd = pmd_alloc(mm, pud, address); 2482 if (!pmd) 2483 return VM_FAULT_OOM; 2484 pte = pte_alloc_map(mm, pmd, address); 2485 if (!pte) 2486 return VM_FAULT_OOM; 2487 2488 return handle_pte_fault(mm, vma, address, pte, pmd, write_access); 2489} 2490 2491#ifndef __PAGETABLE_PUD_FOLDED 2492/* 2493 * Allocate page upper directory. 2494 * We've already handled the fast-path in-line. 2495 */ 2496int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 2497{ 2498 pud_t *new = pud_alloc_one(mm, address); 2499 if (!new) 2500 return -ENOMEM; 2501 2502 spin_lock(&mm->page_table_lock); 2503 if (pgd_present(*pgd)) /* Another has populated it */ 2504 pud_free(new); 2505 else 2506 pgd_populate(mm, pgd, new); 2507 spin_unlock(&mm->page_table_lock); 2508 return 0; 2509} 2510#endif /* __PAGETABLE_PUD_FOLDED */ 2511 2512#ifndef __PAGETABLE_PMD_FOLDED 2513/* 2514 * Allocate page middle directory. 2515 * We've already handled the fast-path in-line. 2516 */ 2517int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 2518{ 2519 pmd_t *new = pmd_alloc_one(mm, address); 2520 if (!new) 2521 return -ENOMEM; 2522 2523 spin_lock(&mm->page_table_lock); 2524#ifndef __ARCH_HAS_4LEVEL_HACK 2525 if (pud_present(*pud)) /* Another has populated it */ 2526 pmd_free(new); 2527 else 2528 pud_populate(mm, pud, new); 2529#else 2530 if (pgd_present(*pud)) /* Another has populated it */ 2531 pmd_free(new); 2532 else 2533 pgd_populate(mm, pud, new); 2534#endif /* __ARCH_HAS_4LEVEL_HACK */ 2535 spin_unlock(&mm->page_table_lock); 2536 return 0; 2537} 2538#endif /* __PAGETABLE_PMD_FOLDED */ 2539 2540int make_pages_present(unsigned long addr, unsigned long end) 2541{ 2542 int ret, len, write; 2543 struct vm_area_struct * vma; 2544 2545 vma = find_vma(current->mm, addr); 2546 if (!vma) 2547 return -1; 2548 write = (vma->vm_flags & VM_WRITE) != 0; 2549 BUG_ON(addr >= end); 2550 BUG_ON(end > vma->vm_end); 2551 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; 2552 ret = get_user_pages(current, current->mm, addr, 2553 len, write, 0, NULL, NULL); 2554 if (ret < 0) 2555 return ret; 2556 return ret == len ? 0 : -1; 2557} 2558 2559#if !defined(__HAVE_ARCH_GATE_AREA) 2560 2561#if defined(AT_SYSINFO_EHDR) 2562static struct vm_area_struct gate_vma; 2563 2564static int __init gate_vma_init(void) 2565{ 2566 gate_vma.vm_mm = NULL; 2567 gate_vma.vm_start = FIXADDR_USER_START; 2568 gate_vma.vm_end = FIXADDR_USER_END; 2569 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; 2570 gate_vma.vm_page_prot = __P101; 2571 /* 2572 * Make sure the vDSO gets into every core dump. 2573 * Dumping its contents makes post-mortem fully interpretable later 2574 * without matching up the same kernel and hardware config to see 2575 * what PC values meant. 2576 */ 2577 gate_vma.vm_flags |= VM_ALWAYSDUMP; 2578 return 0; 2579} 2580__initcall(gate_vma_init); 2581#endif 2582 2583struct vm_area_struct *get_gate_vma(struct task_struct *tsk) 2584{ 2585#ifdef AT_SYSINFO_EHDR 2586 return &gate_vma; 2587#else 2588 return NULL; 2589#endif 2590} 2591 2592int in_gate_area_no_task(unsigned long addr) 2593{ 2594#ifdef AT_SYSINFO_EHDR 2595 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 2596 return 1; 2597#endif 2598 return 0; 2599} 2600 2601#endif /* __HAVE_ARCH_GATE_AREA */ 2602 2603/* 2604 * Access another process' address space. 2605 * Source/target buffer must be kernel space, 2606 * Do not walk the page table directly, use get_user_pages 2607 */ 2608int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) 2609{ 2610 struct mm_struct *mm; 2611 struct vm_area_struct *vma; 2612 struct page *page; 2613 void *old_buf = buf; 2614 2615 mm = get_task_mm(tsk); 2616 if (!mm) 2617 return 0; 2618 2619 down_read(&mm->mmap_sem); 2620 /* ignore errors, just check how much was successfully transferred */ 2621 while (len) { 2622 int bytes, ret, offset; 2623 void *maddr; 2624 2625 ret = get_user_pages(tsk, mm, addr, 1, 2626 write, 1, &page, &vma); 2627 if (ret <= 0) 2628 break; 2629 2630 bytes = len; 2631 offset = addr & (PAGE_SIZE-1); 2632 if (bytes > PAGE_SIZE-offset) 2633 bytes = PAGE_SIZE-offset; 2634 2635 maddr = kmap(page); 2636 if (write) { 2637 copy_to_user_page(vma, page, addr, 2638 maddr + offset, buf, bytes); 2639 set_page_dirty_lock(page); 2640 } else { 2641 copy_from_user_page(vma, page, addr, 2642 buf, maddr + offset, bytes); 2643 } 2644 kunmap(page); 2645 page_cache_release(page); 2646 len -= bytes; 2647 buf += bytes; 2648 addr += bytes; 2649 } 2650 up_read(&mm->mmap_sem); 2651 mmput(mm); 2652 2653 return buf - old_buf; 2654} 2655 2656/* 2657 * Print the name of a VMA. 2658 */ 2659void print_vma_addr(char *prefix, unsigned long ip) 2660{ 2661 struct mm_struct *mm = current->mm; 2662 struct vm_area_struct *vma; 2663 2664 down_read(&mm->mmap_sem); 2665 vma = find_vma(mm, ip); 2666 if (vma && vma->vm_file) { 2667 struct file *f = vma->vm_file; 2668 char *buf = (char *)__get_free_page(GFP_KERNEL); 2669 if (buf) { 2670 char *p, *s; 2671 2672 p = d_path(f->f_dentry, f->f_vfsmnt, buf, PAGE_SIZE); 2673 if (IS_ERR(p)) 2674 p = "?"; 2675 s = strrchr(p, '/'); 2676 if (s) 2677 p = s+1; 2678 printk("%s%s[%lx+%lx]", prefix, p, 2679 vma->vm_start, 2680 vma->vm_end - vma->vm_start); 2681 free_page((unsigned long)buf); 2682 } 2683 } 2684 up_read(¤t->mm->mmap_sem); 2685} 2686