memory.c revision 4294621f41a85497019fae64341aa5351a1921b7
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/init.h> 51 52#include <asm/pgalloc.h> 53#include <asm/uaccess.h> 54#include <asm/tlb.h> 55#include <asm/tlbflush.h> 56#include <asm/pgtable.h> 57 58#include <linux/swapops.h> 59#include <linux/elf.h> 60 61#ifndef CONFIG_NEED_MULTIPLE_NODES 62/* use the per-pgdat data instead for discontigmem - mbligh */ 63unsigned long max_mapnr; 64struct page *mem_map; 65 66EXPORT_SYMBOL(max_mapnr); 67EXPORT_SYMBOL(mem_map); 68#endif 69 70unsigned long num_physpages; 71/* 72 * A number of key systems in x86 including ioremap() rely on the assumption 73 * that high_memory defines the upper bound on direct map memory, then end 74 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and 75 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL 76 * and ZONE_HIGHMEM. 77 */ 78void * high_memory; 79unsigned long vmalloc_earlyreserve; 80 81EXPORT_SYMBOL(num_physpages); 82EXPORT_SYMBOL(high_memory); 83EXPORT_SYMBOL(vmalloc_earlyreserve); 84 85/* 86 * If a p?d_bad entry is found while walking page tables, report 87 * the error, before resetting entry to p?d_none. Usually (but 88 * very seldom) called out from the p?d_none_or_clear_bad macros. 89 */ 90 91void pgd_clear_bad(pgd_t *pgd) 92{ 93 pgd_ERROR(*pgd); 94 pgd_clear(pgd); 95} 96 97void pud_clear_bad(pud_t *pud) 98{ 99 pud_ERROR(*pud); 100 pud_clear(pud); 101} 102 103void pmd_clear_bad(pmd_t *pmd) 104{ 105 pmd_ERROR(*pmd); 106 pmd_clear(pmd); 107} 108 109/* 110 * Note: this doesn't free the actual pages themselves. That 111 * has been handled earlier when unmapping all the memory regions. 112 */ 113static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) 114{ 115 struct page *page = pmd_page(*pmd); 116 pmd_clear(pmd); 117 pte_free_tlb(tlb, page); 118 dec_page_state(nr_page_table_pages); 119 tlb->mm->nr_ptes--; 120} 121 122static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 123 unsigned long addr, unsigned long end, 124 unsigned long floor, unsigned long ceiling) 125{ 126 pmd_t *pmd; 127 unsigned long next; 128 unsigned long start; 129 130 start = addr; 131 pmd = pmd_offset(pud, addr); 132 do { 133 next = pmd_addr_end(addr, end); 134 if (pmd_none_or_clear_bad(pmd)) 135 continue; 136 free_pte_range(tlb, pmd); 137 } while (pmd++, addr = next, addr != end); 138 139 start &= PUD_MASK; 140 if (start < floor) 141 return; 142 if (ceiling) { 143 ceiling &= PUD_MASK; 144 if (!ceiling) 145 return; 146 } 147 if (end - 1 > ceiling - 1) 148 return; 149 150 pmd = pmd_offset(pud, start); 151 pud_clear(pud); 152 pmd_free_tlb(tlb, pmd); 153} 154 155static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 156 unsigned long addr, unsigned long end, 157 unsigned long floor, unsigned long ceiling) 158{ 159 pud_t *pud; 160 unsigned long next; 161 unsigned long start; 162 163 start = addr; 164 pud = pud_offset(pgd, addr); 165 do { 166 next = pud_addr_end(addr, end); 167 if (pud_none_or_clear_bad(pud)) 168 continue; 169 free_pmd_range(tlb, pud, addr, next, floor, ceiling); 170 } while (pud++, addr = next, addr != end); 171 172 start &= PGDIR_MASK; 173 if (start < floor) 174 return; 175 if (ceiling) { 176 ceiling &= PGDIR_MASK; 177 if (!ceiling) 178 return; 179 } 180 if (end - 1 > ceiling - 1) 181 return; 182 183 pud = pud_offset(pgd, start); 184 pgd_clear(pgd); 185 pud_free_tlb(tlb, pud); 186} 187 188/* 189 * This function frees user-level page tables of a process. 190 * 191 * Must be called with pagetable lock held. 192 */ 193void free_pgd_range(struct mmu_gather **tlb, 194 unsigned long addr, unsigned long end, 195 unsigned long floor, unsigned long ceiling) 196{ 197 pgd_t *pgd; 198 unsigned long next; 199 unsigned long start; 200 201 /* 202 * The next few lines have given us lots of grief... 203 * 204 * Why are we testing PMD* at this top level? Because often 205 * there will be no work to do at all, and we'd prefer not to 206 * go all the way down to the bottom just to discover that. 207 * 208 * Why all these "- 1"s? Because 0 represents both the bottom 209 * of the address space and the top of it (using -1 for the 210 * top wouldn't help much: the masks would do the wrong thing). 211 * The rule is that addr 0 and floor 0 refer to the bottom of 212 * the address space, but end 0 and ceiling 0 refer to the top 213 * Comparisons need to use "end - 1" and "ceiling - 1" (though 214 * that end 0 case should be mythical). 215 * 216 * Wherever addr is brought up or ceiling brought down, we must 217 * be careful to reject "the opposite 0" before it confuses the 218 * subsequent tests. But what about where end is brought down 219 * by PMD_SIZE below? no, end can't go down to 0 there. 220 * 221 * Whereas we round start (addr) and ceiling down, by different 222 * masks at different levels, in order to test whether a table 223 * now has no other vmas using it, so can be freed, we don't 224 * bother to round floor or end up - the tests don't need that. 225 */ 226 227 addr &= PMD_MASK; 228 if (addr < floor) { 229 addr += PMD_SIZE; 230 if (!addr) 231 return; 232 } 233 if (ceiling) { 234 ceiling &= PMD_MASK; 235 if (!ceiling) 236 return; 237 } 238 if (end - 1 > ceiling - 1) 239 end -= PMD_SIZE; 240 if (addr > end - 1) 241 return; 242 243 start = addr; 244 pgd = pgd_offset((*tlb)->mm, addr); 245 do { 246 next = pgd_addr_end(addr, end); 247 if (pgd_none_or_clear_bad(pgd)) 248 continue; 249 free_pud_range(*tlb, pgd, addr, next, floor, ceiling); 250 } while (pgd++, addr = next, addr != end); 251 252 if (!(*tlb)->fullmm) 253 flush_tlb_pgtables((*tlb)->mm, start, end); 254} 255 256void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, 257 unsigned long floor, unsigned long ceiling) 258{ 259 while (vma) { 260 struct vm_area_struct *next = vma->vm_next; 261 unsigned long addr = vma->vm_start; 262 263 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) { 264 hugetlb_free_pgd_range(tlb, addr, vma->vm_end, 265 floor, next? next->vm_start: ceiling); 266 } else { 267 /* 268 * Optimization: gather nearby vmas into one call down 269 */ 270 while (next && next->vm_start <= vma->vm_end + PMD_SIZE 271 && !is_hugepage_only_range(vma->vm_mm, next->vm_start, 272 HPAGE_SIZE)) { 273 vma = next; 274 next = vma->vm_next; 275 } 276 free_pgd_range(tlb, addr, vma->vm_end, 277 floor, next? next->vm_start: ceiling); 278 } 279 vma = next; 280 } 281} 282 283pte_t fastcall *pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, 284 unsigned long address) 285{ 286 if (!pmd_present(*pmd)) { 287 struct page *new; 288 289 spin_unlock(&mm->page_table_lock); 290 new = pte_alloc_one(mm, address); 291 spin_lock(&mm->page_table_lock); 292 if (!new) 293 return NULL; 294 /* 295 * Because we dropped the lock, we should re-check the 296 * entry, as somebody else could have populated it.. 297 */ 298 if (pmd_present(*pmd)) { 299 pte_free(new); 300 goto out; 301 } 302 mm->nr_ptes++; 303 inc_page_state(nr_page_table_pages); 304 pmd_populate(mm, pmd, new); 305 } 306out: 307 return pte_offset_map(pmd, address); 308} 309 310pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address) 311{ 312 if (!pmd_present(*pmd)) { 313 pte_t *new; 314 315 spin_unlock(&mm->page_table_lock); 316 new = pte_alloc_one_kernel(mm, address); 317 spin_lock(&mm->page_table_lock); 318 if (!new) 319 return NULL; 320 321 /* 322 * Because we dropped the lock, we should re-check the 323 * entry, as somebody else could have populated it.. 324 */ 325 if (pmd_present(*pmd)) { 326 pte_free_kernel(new); 327 goto out; 328 } 329 pmd_populate_kernel(mm, pmd, new); 330 } 331out: 332 return pte_offset_kernel(pmd, address); 333} 334 335/* 336 * copy one vm_area from one task to the other. Assumes the page tables 337 * already present in the new task to be cleared in the whole range 338 * covered by this vma. 339 * 340 * dst->page_table_lock is held on entry and exit, 341 * but may be dropped within p[mg]d_alloc() and pte_alloc_map(). 342 */ 343 344static inline void 345copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, 346 pte_t *dst_pte, pte_t *src_pte, unsigned long vm_flags, 347 unsigned long addr) 348{ 349 pte_t pte = *src_pte; 350 struct page *page; 351 unsigned long pfn; 352 353 /* pte contains position in swap or file, so copy. */ 354 if (unlikely(!pte_present(pte))) { 355 if (!pte_file(pte)) { 356 swap_duplicate(pte_to_swp_entry(pte)); 357 /* make sure dst_mm is on swapoff's mmlist. */ 358 if (unlikely(list_empty(&dst_mm->mmlist))) { 359 spin_lock(&mmlist_lock); 360 list_add(&dst_mm->mmlist, &src_mm->mmlist); 361 spin_unlock(&mmlist_lock); 362 } 363 } 364 set_pte_at(dst_mm, addr, dst_pte, pte); 365 return; 366 } 367 368 pfn = pte_pfn(pte); 369 /* the pte points outside of valid memory, the 370 * mapping is assumed to be good, meaningful 371 * and not mapped via rmap - duplicate the 372 * mapping as is. 373 */ 374 page = NULL; 375 if (pfn_valid(pfn)) 376 page = pfn_to_page(pfn); 377 378 if (!page || PageReserved(page)) { 379 set_pte_at(dst_mm, addr, dst_pte, pte); 380 return; 381 } 382 383 /* 384 * If it's a COW mapping, write protect it both 385 * in the parent and the child 386 */ 387 if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) { 388 ptep_set_wrprotect(src_mm, addr, src_pte); 389 pte = *src_pte; 390 } 391 392 /* 393 * If it's a shared mapping, mark it clean in 394 * the child 395 */ 396 if (vm_flags & VM_SHARED) 397 pte = pte_mkclean(pte); 398 pte = pte_mkold(pte); 399 get_page(page); 400 if (PageAnon(page)) 401 inc_mm_counter(dst_mm, anon_rss); 402 else 403 inc_mm_counter(dst_mm, file_rss); 404 set_pte_at(dst_mm, addr, dst_pte, pte); 405 page_dup_rmap(page); 406} 407 408static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 409 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 410 unsigned long addr, unsigned long end) 411{ 412 pte_t *src_pte, *dst_pte; 413 unsigned long vm_flags = vma->vm_flags; 414 int progress = 0; 415 416again: 417 dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr); 418 if (!dst_pte) 419 return -ENOMEM; 420 src_pte = pte_offset_map_nested(src_pmd, addr); 421 422 spin_lock(&src_mm->page_table_lock); 423 do { 424 /* 425 * We are holding two locks at this point - either of them 426 * could generate latencies in another task on another CPU. 427 */ 428 if (progress >= 32) { 429 progress = 0; 430 if (need_resched() || 431 need_lockbreak(&src_mm->page_table_lock) || 432 need_lockbreak(&dst_mm->page_table_lock)) 433 break; 434 } 435 if (pte_none(*src_pte)) { 436 progress++; 437 continue; 438 } 439 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vm_flags, addr); 440 progress += 8; 441 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 442 spin_unlock(&src_mm->page_table_lock); 443 444 pte_unmap_nested(src_pte - 1); 445 pte_unmap(dst_pte - 1); 446 cond_resched_lock(&dst_mm->page_table_lock); 447 if (addr != end) 448 goto again; 449 return 0; 450} 451 452static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 453 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 454 unsigned long addr, unsigned long end) 455{ 456 pmd_t *src_pmd, *dst_pmd; 457 unsigned long next; 458 459 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 460 if (!dst_pmd) 461 return -ENOMEM; 462 src_pmd = pmd_offset(src_pud, addr); 463 do { 464 next = pmd_addr_end(addr, end); 465 if (pmd_none_or_clear_bad(src_pmd)) 466 continue; 467 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 468 vma, addr, next)) 469 return -ENOMEM; 470 } while (dst_pmd++, src_pmd++, addr = next, addr != end); 471 return 0; 472} 473 474static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 475 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 476 unsigned long addr, unsigned long end) 477{ 478 pud_t *src_pud, *dst_pud; 479 unsigned long next; 480 481 dst_pud = pud_alloc(dst_mm, dst_pgd, addr); 482 if (!dst_pud) 483 return -ENOMEM; 484 src_pud = pud_offset(src_pgd, addr); 485 do { 486 next = pud_addr_end(addr, end); 487 if (pud_none_or_clear_bad(src_pud)) 488 continue; 489 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 490 vma, addr, next)) 491 return -ENOMEM; 492 } while (dst_pud++, src_pud++, addr = next, addr != end); 493 return 0; 494} 495 496int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 497 struct vm_area_struct *vma) 498{ 499 pgd_t *src_pgd, *dst_pgd; 500 unsigned long next; 501 unsigned long addr = vma->vm_start; 502 unsigned long end = vma->vm_end; 503 504 /* 505 * Don't copy ptes where a page fault will fill them correctly. 506 * Fork becomes much lighter when there are big shared or private 507 * readonly mappings. The tradeoff is that copy_page_range is more 508 * efficient than faulting. 509 */ 510 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) { 511 if (!vma->anon_vma) 512 return 0; 513 } 514 515 if (is_vm_hugetlb_page(vma)) 516 return copy_hugetlb_page_range(dst_mm, src_mm, vma); 517 518 dst_pgd = pgd_offset(dst_mm, addr); 519 src_pgd = pgd_offset(src_mm, addr); 520 do { 521 next = pgd_addr_end(addr, end); 522 if (pgd_none_or_clear_bad(src_pgd)) 523 continue; 524 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, 525 vma, addr, next)) 526 return -ENOMEM; 527 } while (dst_pgd++, src_pgd++, addr = next, addr != end); 528 return 0; 529} 530 531static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 532 unsigned long addr, unsigned long end, 533 struct zap_details *details) 534{ 535 pte_t *pte; 536 537 pte = pte_offset_map(pmd, addr); 538 do { 539 pte_t ptent = *pte; 540 if (pte_none(ptent)) 541 continue; 542 if (pte_present(ptent)) { 543 struct page *page = NULL; 544 unsigned long pfn = pte_pfn(ptent); 545 if (pfn_valid(pfn)) { 546 page = pfn_to_page(pfn); 547 if (PageReserved(page)) 548 page = NULL; 549 } 550 if (unlikely(details) && page) { 551 /* 552 * unmap_shared_mapping_pages() wants to 553 * invalidate cache without truncating: 554 * unmap shared but keep private pages. 555 */ 556 if (details->check_mapping && 557 details->check_mapping != page->mapping) 558 continue; 559 /* 560 * Each page->index must be checked when 561 * invalidating or truncating nonlinear. 562 */ 563 if (details->nonlinear_vma && 564 (page->index < details->first_index || 565 page->index > details->last_index)) 566 continue; 567 } 568 ptent = ptep_get_and_clear_full(tlb->mm, addr, pte, 569 tlb->fullmm); 570 tlb_remove_tlb_entry(tlb, pte, addr); 571 if (unlikely(!page)) 572 continue; 573 if (unlikely(details) && details->nonlinear_vma 574 && linear_page_index(details->nonlinear_vma, 575 addr) != page->index) 576 set_pte_at(tlb->mm, addr, pte, 577 pgoff_to_pte(page->index)); 578 if (PageAnon(page)) 579 dec_mm_counter(tlb->mm, anon_rss); 580 else { 581 if (pte_dirty(ptent)) 582 set_page_dirty(page); 583 if (pte_young(ptent)) 584 mark_page_accessed(page); 585 dec_mm_counter(tlb->mm, file_rss); 586 } 587 page_remove_rmap(page); 588 tlb_remove_page(tlb, page); 589 continue; 590 } 591 /* 592 * If details->check_mapping, we leave swap entries; 593 * if details->nonlinear_vma, we leave file entries. 594 */ 595 if (unlikely(details)) 596 continue; 597 if (!pte_file(ptent)) 598 free_swap_and_cache(pte_to_swp_entry(ptent)); 599 pte_clear_full(tlb->mm, addr, pte, tlb->fullmm); 600 } while (pte++, addr += PAGE_SIZE, addr != end); 601 pte_unmap(pte - 1); 602} 603 604static inline void zap_pmd_range(struct mmu_gather *tlb, pud_t *pud, 605 unsigned long addr, unsigned long end, 606 struct zap_details *details) 607{ 608 pmd_t *pmd; 609 unsigned long next; 610 611 pmd = pmd_offset(pud, addr); 612 do { 613 next = pmd_addr_end(addr, end); 614 if (pmd_none_or_clear_bad(pmd)) 615 continue; 616 zap_pte_range(tlb, pmd, addr, next, details); 617 } while (pmd++, addr = next, addr != end); 618} 619 620static inline void zap_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 621 unsigned long addr, unsigned long end, 622 struct zap_details *details) 623{ 624 pud_t *pud; 625 unsigned long next; 626 627 pud = pud_offset(pgd, addr); 628 do { 629 next = pud_addr_end(addr, end); 630 if (pud_none_or_clear_bad(pud)) 631 continue; 632 zap_pmd_range(tlb, pud, addr, next, details); 633 } while (pud++, addr = next, addr != end); 634} 635 636static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 637 unsigned long addr, unsigned long end, 638 struct zap_details *details) 639{ 640 pgd_t *pgd; 641 unsigned long next; 642 643 if (details && !details->check_mapping && !details->nonlinear_vma) 644 details = NULL; 645 646 BUG_ON(addr >= end); 647 tlb_start_vma(tlb, vma); 648 pgd = pgd_offset(vma->vm_mm, addr); 649 do { 650 next = pgd_addr_end(addr, end); 651 if (pgd_none_or_clear_bad(pgd)) 652 continue; 653 zap_pud_range(tlb, pgd, addr, next, details); 654 } while (pgd++, addr = next, addr != end); 655 tlb_end_vma(tlb, vma); 656} 657 658#ifdef CONFIG_PREEMPT 659# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) 660#else 661/* No preempt: go for improved straight-line efficiency */ 662# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) 663#endif 664 665/** 666 * unmap_vmas - unmap a range of memory covered by a list of vma's 667 * @tlbp: address of the caller's struct mmu_gather 668 * @mm: the controlling mm_struct 669 * @vma: the starting vma 670 * @start_addr: virtual address at which to start unmapping 671 * @end_addr: virtual address at which to end unmapping 672 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here 673 * @details: details of nonlinear truncation or shared cache invalidation 674 * 675 * Returns the end address of the unmapping (restart addr if interrupted). 676 * 677 * Unmap all pages in the vma list. Called under page_table_lock. 678 * 679 * We aim to not hold page_table_lock for too long (for scheduling latency 680 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to 681 * return the ending mmu_gather to the caller. 682 * 683 * Only addresses between `start' and `end' will be unmapped. 684 * 685 * The VMA list must be sorted in ascending virtual address order. 686 * 687 * unmap_vmas() assumes that the caller will flush the whole unmapped address 688 * range after unmap_vmas() returns. So the only responsibility here is to 689 * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 690 * drops the lock and schedules. 691 */ 692unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, 693 struct vm_area_struct *vma, unsigned long start_addr, 694 unsigned long end_addr, unsigned long *nr_accounted, 695 struct zap_details *details) 696{ 697 unsigned long zap_bytes = ZAP_BLOCK_SIZE; 698 unsigned long tlb_start = 0; /* For tlb_finish_mmu */ 699 int tlb_start_valid = 0; 700 unsigned long start = start_addr; 701 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; 702 int fullmm = (*tlbp)->fullmm; 703 704 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { 705 unsigned long end; 706 707 start = max(vma->vm_start, start_addr); 708 if (start >= vma->vm_end) 709 continue; 710 end = min(vma->vm_end, end_addr); 711 if (end <= vma->vm_start) 712 continue; 713 714 if (vma->vm_flags & VM_ACCOUNT) 715 *nr_accounted += (end - start) >> PAGE_SHIFT; 716 717 while (start != end) { 718 unsigned long block; 719 720 if (!tlb_start_valid) { 721 tlb_start = start; 722 tlb_start_valid = 1; 723 } 724 725 if (is_vm_hugetlb_page(vma)) { 726 block = end - start; 727 unmap_hugepage_range(vma, start, end); 728 } else { 729 block = min(zap_bytes, end - start); 730 unmap_page_range(*tlbp, vma, start, 731 start + block, details); 732 } 733 734 start += block; 735 zap_bytes -= block; 736 if ((long)zap_bytes > 0) 737 continue; 738 739 tlb_finish_mmu(*tlbp, tlb_start, start); 740 741 if (need_resched() || 742 need_lockbreak(&mm->page_table_lock) || 743 (i_mmap_lock && need_lockbreak(i_mmap_lock))) { 744 if (i_mmap_lock) { 745 /* must reset count of rss freed */ 746 *tlbp = tlb_gather_mmu(mm, fullmm); 747 goto out; 748 } 749 spin_unlock(&mm->page_table_lock); 750 cond_resched(); 751 spin_lock(&mm->page_table_lock); 752 } 753 754 *tlbp = tlb_gather_mmu(mm, fullmm); 755 tlb_start_valid = 0; 756 zap_bytes = ZAP_BLOCK_SIZE; 757 } 758 } 759out: 760 return start; /* which is now the end (or restart) address */ 761} 762 763/** 764 * zap_page_range - remove user pages in a given range 765 * @vma: vm_area_struct holding the applicable pages 766 * @address: starting address of pages to zap 767 * @size: number of bytes to zap 768 * @details: details of nonlinear truncation or shared cache invalidation 769 */ 770unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, 771 unsigned long size, struct zap_details *details) 772{ 773 struct mm_struct *mm = vma->vm_mm; 774 struct mmu_gather *tlb; 775 unsigned long end = address + size; 776 unsigned long nr_accounted = 0; 777 778 if (is_vm_hugetlb_page(vma)) { 779 zap_hugepage_range(vma, address, size); 780 return end; 781 } 782 783 lru_add_drain(); 784 spin_lock(&mm->page_table_lock); 785 tlb = tlb_gather_mmu(mm, 0); 786 end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details); 787 tlb_finish_mmu(tlb, address, end); 788 spin_unlock(&mm->page_table_lock); 789 return end; 790} 791 792/* 793 * Do a quick page-table lookup for a single page. 794 * mm->page_table_lock must be held. 795 */ 796static struct page *__follow_page(struct mm_struct *mm, unsigned long address, 797 int read, int write, int accessed) 798{ 799 pgd_t *pgd; 800 pud_t *pud; 801 pmd_t *pmd; 802 pte_t *ptep, pte; 803 unsigned long pfn; 804 struct page *page; 805 806 page = follow_huge_addr(mm, address, write); 807 if (! IS_ERR(page)) 808 return page; 809 810 pgd = pgd_offset(mm, address); 811 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 812 goto out; 813 814 pud = pud_offset(pgd, address); 815 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 816 goto out; 817 818 pmd = pmd_offset(pud, address); 819 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 820 goto out; 821 if (pmd_huge(*pmd)) 822 return follow_huge_pmd(mm, address, pmd, write); 823 824 ptep = pte_offset_map(pmd, address); 825 if (!ptep) 826 goto out; 827 828 pte = *ptep; 829 pte_unmap(ptep); 830 if (pte_present(pte)) { 831 if (write && !pte_write(pte)) 832 goto out; 833 if (read && !pte_read(pte)) 834 goto out; 835 pfn = pte_pfn(pte); 836 if (pfn_valid(pfn)) { 837 page = pfn_to_page(pfn); 838 if (accessed) { 839 if (write && !pte_dirty(pte) &&!PageDirty(page)) 840 set_page_dirty(page); 841 mark_page_accessed(page); 842 } 843 return page; 844 } 845 } 846 847out: 848 return NULL; 849} 850 851inline struct page * 852follow_page(struct mm_struct *mm, unsigned long address, int write) 853{ 854 return __follow_page(mm, address, 0, write, 1); 855} 856 857/* 858 * check_user_page_readable() can be called frm niterrupt context by oprofile, 859 * so we need to avoid taking any non-irq-safe locks 860 */ 861int check_user_page_readable(struct mm_struct *mm, unsigned long address) 862{ 863 return __follow_page(mm, address, 1, 0, 0) != NULL; 864} 865EXPORT_SYMBOL(check_user_page_readable); 866 867static inline int 868untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma, 869 unsigned long address) 870{ 871 pgd_t *pgd; 872 pud_t *pud; 873 pmd_t *pmd; 874 875 /* Check if the vma is for an anonymous mapping. */ 876 if (vma->vm_ops && vma->vm_ops->nopage) 877 return 0; 878 879 /* Check if page directory entry exists. */ 880 pgd = pgd_offset(mm, address); 881 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 882 return 1; 883 884 pud = pud_offset(pgd, address); 885 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 886 return 1; 887 888 /* Check if page middle directory entry exists. */ 889 pmd = pmd_offset(pud, address); 890 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 891 return 1; 892 893 /* There is a pte slot for 'address' in 'mm'. */ 894 return 0; 895} 896 897int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 898 unsigned long start, int len, int write, int force, 899 struct page **pages, struct vm_area_struct **vmas) 900{ 901 int i; 902 unsigned int flags; 903 904 /* 905 * Require read or write permissions. 906 * If 'force' is set, we only require the "MAY" flags. 907 */ 908 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 909 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 910 i = 0; 911 912 do { 913 struct vm_area_struct * vma; 914 915 vma = find_extend_vma(mm, start); 916 if (!vma && in_gate_area(tsk, start)) { 917 unsigned long pg = start & PAGE_MASK; 918 struct vm_area_struct *gate_vma = get_gate_vma(tsk); 919 pgd_t *pgd; 920 pud_t *pud; 921 pmd_t *pmd; 922 pte_t *pte; 923 if (write) /* user gate pages are read-only */ 924 return i ? : -EFAULT; 925 if (pg > TASK_SIZE) 926 pgd = pgd_offset_k(pg); 927 else 928 pgd = pgd_offset_gate(mm, pg); 929 BUG_ON(pgd_none(*pgd)); 930 pud = pud_offset(pgd, pg); 931 BUG_ON(pud_none(*pud)); 932 pmd = pmd_offset(pud, pg); 933 if (pmd_none(*pmd)) 934 return i ? : -EFAULT; 935 pte = pte_offset_map(pmd, pg); 936 if (pte_none(*pte)) { 937 pte_unmap(pte); 938 return i ? : -EFAULT; 939 } 940 if (pages) { 941 pages[i] = pte_page(*pte); 942 get_page(pages[i]); 943 } 944 pte_unmap(pte); 945 if (vmas) 946 vmas[i] = gate_vma; 947 i++; 948 start += PAGE_SIZE; 949 len--; 950 continue; 951 } 952 953 if (!vma || (vma->vm_flags & VM_IO) 954 || !(flags & vma->vm_flags)) 955 return i ? : -EFAULT; 956 957 if (is_vm_hugetlb_page(vma)) { 958 i = follow_hugetlb_page(mm, vma, pages, vmas, 959 &start, &len, i); 960 continue; 961 } 962 spin_lock(&mm->page_table_lock); 963 do { 964 int write_access = write; 965 struct page *page; 966 967 cond_resched_lock(&mm->page_table_lock); 968 while (!(page = follow_page(mm, start, write_access))) { 969 int ret; 970 971 /* 972 * Shortcut for anonymous pages. We don't want 973 * to force the creation of pages tables for 974 * insanely big anonymously mapped areas that 975 * nobody touched so far. This is important 976 * for doing a core dump for these mappings. 977 */ 978 if (!write && untouched_anonymous_page(mm,vma,start)) { 979 page = ZERO_PAGE(start); 980 break; 981 } 982 spin_unlock(&mm->page_table_lock); 983 ret = __handle_mm_fault(mm, vma, start, write_access); 984 985 /* 986 * The VM_FAULT_WRITE bit tells us that do_wp_page has 987 * broken COW when necessary, even if maybe_mkwrite 988 * decided not to set pte_write. We can thus safely do 989 * subsequent page lookups as if they were reads. 990 */ 991 if (ret & VM_FAULT_WRITE) 992 write_access = 0; 993 994 switch (ret & ~VM_FAULT_WRITE) { 995 case VM_FAULT_MINOR: 996 tsk->min_flt++; 997 break; 998 case VM_FAULT_MAJOR: 999 tsk->maj_flt++; 1000 break; 1001 case VM_FAULT_SIGBUS: 1002 return i ? i : -EFAULT; 1003 case VM_FAULT_OOM: 1004 return i ? i : -ENOMEM; 1005 default: 1006 BUG(); 1007 } 1008 spin_lock(&mm->page_table_lock); 1009 } 1010 if (pages) { 1011 pages[i] = page; 1012 flush_dcache_page(page); 1013 if (!PageReserved(page)) 1014 page_cache_get(page); 1015 } 1016 if (vmas) 1017 vmas[i] = vma; 1018 i++; 1019 start += PAGE_SIZE; 1020 len--; 1021 } while (len && start < vma->vm_end); 1022 spin_unlock(&mm->page_table_lock); 1023 } while (len); 1024 return i; 1025} 1026EXPORT_SYMBOL(get_user_pages); 1027 1028static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1029 unsigned long addr, unsigned long end, pgprot_t prot) 1030{ 1031 pte_t *pte; 1032 1033 pte = pte_alloc_map(mm, pmd, addr); 1034 if (!pte) 1035 return -ENOMEM; 1036 do { 1037 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(addr), prot)); 1038 BUG_ON(!pte_none(*pte)); 1039 set_pte_at(mm, addr, pte, zero_pte); 1040 } while (pte++, addr += PAGE_SIZE, addr != end); 1041 pte_unmap(pte - 1); 1042 return 0; 1043} 1044 1045static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, 1046 unsigned long addr, unsigned long end, pgprot_t prot) 1047{ 1048 pmd_t *pmd; 1049 unsigned long next; 1050 1051 pmd = pmd_alloc(mm, pud, addr); 1052 if (!pmd) 1053 return -ENOMEM; 1054 do { 1055 next = pmd_addr_end(addr, end); 1056 if (zeromap_pte_range(mm, pmd, addr, next, prot)) 1057 return -ENOMEM; 1058 } while (pmd++, addr = next, addr != end); 1059 return 0; 1060} 1061 1062static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1063 unsigned long addr, unsigned long end, pgprot_t prot) 1064{ 1065 pud_t *pud; 1066 unsigned long next; 1067 1068 pud = pud_alloc(mm, pgd, addr); 1069 if (!pud) 1070 return -ENOMEM; 1071 do { 1072 next = pud_addr_end(addr, end); 1073 if (zeromap_pmd_range(mm, pud, addr, next, prot)) 1074 return -ENOMEM; 1075 } while (pud++, addr = next, addr != end); 1076 return 0; 1077} 1078 1079int zeromap_page_range(struct vm_area_struct *vma, 1080 unsigned long addr, unsigned long size, pgprot_t prot) 1081{ 1082 pgd_t *pgd; 1083 unsigned long next; 1084 unsigned long end = addr + size; 1085 struct mm_struct *mm = vma->vm_mm; 1086 int err; 1087 1088 BUG_ON(addr >= end); 1089 pgd = pgd_offset(mm, addr); 1090 flush_cache_range(vma, addr, end); 1091 spin_lock(&mm->page_table_lock); 1092 do { 1093 next = pgd_addr_end(addr, end); 1094 err = zeromap_pud_range(mm, pgd, addr, next, prot); 1095 if (err) 1096 break; 1097 } while (pgd++, addr = next, addr != end); 1098 spin_unlock(&mm->page_table_lock); 1099 return err; 1100} 1101 1102/* 1103 * maps a range of physical memory into the requested pages. the old 1104 * mappings are removed. any references to nonexistent pages results 1105 * in null mappings (currently treated as "copy-on-access") 1106 */ 1107static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1108 unsigned long addr, unsigned long end, 1109 unsigned long pfn, pgprot_t prot) 1110{ 1111 pte_t *pte; 1112 1113 pte = pte_alloc_map(mm, pmd, addr); 1114 if (!pte) 1115 return -ENOMEM; 1116 do { 1117 BUG_ON(!pte_none(*pte)); 1118 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn))) 1119 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); 1120 pfn++; 1121 } while (pte++, addr += PAGE_SIZE, addr != end); 1122 pte_unmap(pte - 1); 1123 return 0; 1124} 1125 1126static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 1127 unsigned long addr, unsigned long end, 1128 unsigned long pfn, pgprot_t prot) 1129{ 1130 pmd_t *pmd; 1131 unsigned long next; 1132 1133 pfn -= addr >> PAGE_SHIFT; 1134 pmd = pmd_alloc(mm, pud, addr); 1135 if (!pmd) 1136 return -ENOMEM; 1137 do { 1138 next = pmd_addr_end(addr, end); 1139 if (remap_pte_range(mm, pmd, addr, next, 1140 pfn + (addr >> PAGE_SHIFT), prot)) 1141 return -ENOMEM; 1142 } while (pmd++, addr = next, addr != end); 1143 return 0; 1144} 1145 1146static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1147 unsigned long addr, unsigned long end, 1148 unsigned long pfn, pgprot_t prot) 1149{ 1150 pud_t *pud; 1151 unsigned long next; 1152 1153 pfn -= addr >> PAGE_SHIFT; 1154 pud = pud_alloc(mm, pgd, addr); 1155 if (!pud) 1156 return -ENOMEM; 1157 do { 1158 next = pud_addr_end(addr, end); 1159 if (remap_pmd_range(mm, pud, addr, next, 1160 pfn + (addr >> PAGE_SHIFT), prot)) 1161 return -ENOMEM; 1162 } while (pud++, addr = next, addr != end); 1163 return 0; 1164} 1165 1166/* Note: this is only safe if the mm semaphore is held when called. */ 1167int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 1168 unsigned long pfn, unsigned long size, pgprot_t prot) 1169{ 1170 pgd_t *pgd; 1171 unsigned long next; 1172 unsigned long end = addr + PAGE_ALIGN(size); 1173 struct mm_struct *mm = vma->vm_mm; 1174 int err; 1175 1176 /* 1177 * Physically remapped pages are special. Tell the 1178 * rest of the world about it: 1179 * VM_IO tells people not to look at these pages 1180 * (accesses can have side effects). 1181 * VM_RESERVED tells swapout not to try to touch 1182 * this region. 1183 */ 1184 vma->vm_flags |= VM_IO | VM_RESERVED; 1185 1186 BUG_ON(addr >= end); 1187 pfn -= addr >> PAGE_SHIFT; 1188 pgd = pgd_offset(mm, addr); 1189 flush_cache_range(vma, addr, end); 1190 spin_lock(&mm->page_table_lock); 1191 do { 1192 next = pgd_addr_end(addr, end); 1193 err = remap_pud_range(mm, pgd, addr, next, 1194 pfn + (addr >> PAGE_SHIFT), prot); 1195 if (err) 1196 break; 1197 } while (pgd++, addr = next, addr != end); 1198 spin_unlock(&mm->page_table_lock); 1199 return err; 1200} 1201EXPORT_SYMBOL(remap_pfn_range); 1202 1203/* 1204 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when 1205 * servicing faults for write access. In the normal case, do always want 1206 * pte_mkwrite. But get_user_pages can cause write faults for mappings 1207 * that do not have writing enabled, when used by access_process_vm. 1208 */ 1209static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 1210{ 1211 if (likely(vma->vm_flags & VM_WRITE)) 1212 pte = pte_mkwrite(pte); 1213 return pte; 1214} 1215 1216/* 1217 * This routine handles present pages, when users try to write 1218 * to a shared page. It is done by copying the page to a new address 1219 * and decrementing the shared-page counter for the old page. 1220 * 1221 * Note that this routine assumes that the protection checks have been 1222 * done by the caller (the low-level page fault routine in most cases). 1223 * Thus we can safely just mark it writable once we've done any necessary 1224 * COW. 1225 * 1226 * We also mark the page dirty at this point even though the page will 1227 * change only once the write actually happens. This avoids a few races, 1228 * and potentially makes it more efficient. 1229 * 1230 * We hold the mm semaphore and the page_table_lock on entry and exit 1231 * with the page_table_lock released. 1232 */ 1233static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, 1234 unsigned long address, pte_t *page_table, pmd_t *pmd, 1235 pte_t orig_pte) 1236{ 1237 struct page *old_page, *new_page; 1238 unsigned long pfn = pte_pfn(orig_pte); 1239 pte_t entry; 1240 int ret = VM_FAULT_MINOR; 1241 1242 if (unlikely(!pfn_valid(pfn))) { 1243 /* 1244 * Page table corrupted: show pte and kill process. 1245 */ 1246 pte_ERROR(orig_pte); 1247 ret = VM_FAULT_OOM; 1248 goto unlock; 1249 } 1250 old_page = pfn_to_page(pfn); 1251 1252 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { 1253 int reuse = can_share_swap_page(old_page); 1254 unlock_page(old_page); 1255 if (reuse) { 1256 flush_cache_page(vma, address, pfn); 1257 entry = pte_mkyoung(orig_pte); 1258 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1259 ptep_set_access_flags(vma, address, page_table, entry, 1); 1260 update_mmu_cache(vma, address, entry); 1261 lazy_mmu_prot_update(entry); 1262 ret |= VM_FAULT_WRITE; 1263 goto unlock; 1264 } 1265 } 1266 1267 /* 1268 * Ok, we need to copy. Oh, well.. 1269 */ 1270 if (!PageReserved(old_page)) 1271 page_cache_get(old_page); 1272 pte_unmap(page_table); 1273 spin_unlock(&mm->page_table_lock); 1274 1275 if (unlikely(anon_vma_prepare(vma))) 1276 goto oom; 1277 if (old_page == ZERO_PAGE(address)) { 1278 new_page = alloc_zeroed_user_highpage(vma, address); 1279 if (!new_page) 1280 goto oom; 1281 } else { 1282 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1283 if (!new_page) 1284 goto oom; 1285 copy_user_highpage(new_page, old_page, address); 1286 } 1287 1288 /* 1289 * Re-check the pte - we dropped the lock 1290 */ 1291 spin_lock(&mm->page_table_lock); 1292 page_table = pte_offset_map(pmd, address); 1293 if (likely(pte_same(*page_table, orig_pte))) { 1294 if (PageReserved(old_page)) 1295 inc_mm_counter(mm, anon_rss); 1296 else { 1297 page_remove_rmap(old_page); 1298 if (!PageAnon(old_page)) { 1299 inc_mm_counter(mm, anon_rss); 1300 dec_mm_counter(mm, file_rss); 1301 } 1302 } 1303 flush_cache_page(vma, address, pfn); 1304 entry = mk_pte(new_page, vma->vm_page_prot); 1305 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1306 ptep_establish(vma, address, page_table, entry); 1307 update_mmu_cache(vma, address, entry); 1308 lazy_mmu_prot_update(entry); 1309 1310 lru_cache_add_active(new_page); 1311 page_add_anon_rmap(new_page, vma, address); 1312 1313 /* Free the old page.. */ 1314 new_page = old_page; 1315 ret |= VM_FAULT_WRITE; 1316 } 1317 page_cache_release(new_page); 1318 page_cache_release(old_page); 1319unlock: 1320 pte_unmap(page_table); 1321 spin_unlock(&mm->page_table_lock); 1322 return ret; 1323oom: 1324 page_cache_release(old_page); 1325 return VM_FAULT_OOM; 1326} 1327 1328/* 1329 * Helper functions for unmap_mapping_range(). 1330 * 1331 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ 1332 * 1333 * We have to restart searching the prio_tree whenever we drop the lock, 1334 * since the iterator is only valid while the lock is held, and anyway 1335 * a later vma might be split and reinserted earlier while lock dropped. 1336 * 1337 * The list of nonlinear vmas could be handled more efficiently, using 1338 * a placeholder, but handle it in the same way until a need is shown. 1339 * It is important to search the prio_tree before nonlinear list: a vma 1340 * may become nonlinear and be shifted from prio_tree to nonlinear list 1341 * while the lock is dropped; but never shifted from list to prio_tree. 1342 * 1343 * In order to make forward progress despite restarting the search, 1344 * vm_truncate_count is used to mark a vma as now dealt with, so we can 1345 * quickly skip it next time around. Since the prio_tree search only 1346 * shows us those vmas affected by unmapping the range in question, we 1347 * can't efficiently keep all vmas in step with mapping->truncate_count: 1348 * so instead reset them all whenever it wraps back to 0 (then go to 1). 1349 * mapping->truncate_count and vma->vm_truncate_count are protected by 1350 * i_mmap_lock. 1351 * 1352 * In order to make forward progress despite repeatedly restarting some 1353 * large vma, note the restart_addr from unmap_vmas when it breaks out: 1354 * and restart from that address when we reach that vma again. It might 1355 * have been split or merged, shrunk or extended, but never shifted: so 1356 * restart_addr remains valid so long as it remains in the vma's range. 1357 * unmap_mapping_range forces truncate_count to leap over page-aligned 1358 * values so we can save vma's restart_addr in its truncate_count field. 1359 */ 1360#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) 1361 1362static void reset_vma_truncate_counts(struct address_space *mapping) 1363{ 1364 struct vm_area_struct *vma; 1365 struct prio_tree_iter iter; 1366 1367 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) 1368 vma->vm_truncate_count = 0; 1369 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) 1370 vma->vm_truncate_count = 0; 1371} 1372 1373static int unmap_mapping_range_vma(struct vm_area_struct *vma, 1374 unsigned long start_addr, unsigned long end_addr, 1375 struct zap_details *details) 1376{ 1377 unsigned long restart_addr; 1378 int need_break; 1379 1380again: 1381 restart_addr = vma->vm_truncate_count; 1382 if (is_restart_addr(restart_addr) && start_addr < restart_addr) { 1383 start_addr = restart_addr; 1384 if (start_addr >= end_addr) { 1385 /* Top of vma has been split off since last time */ 1386 vma->vm_truncate_count = details->truncate_count; 1387 return 0; 1388 } 1389 } 1390 1391 restart_addr = zap_page_range(vma, start_addr, 1392 end_addr - start_addr, details); 1393 1394 /* 1395 * We cannot rely on the break test in unmap_vmas: 1396 * on the one hand, we don't want to restart our loop 1397 * just because that broke out for the page_table_lock; 1398 * on the other hand, it does no test when vma is small. 1399 */ 1400 need_break = need_resched() || 1401 need_lockbreak(details->i_mmap_lock); 1402 1403 if (restart_addr >= end_addr) { 1404 /* We have now completed this vma: mark it so */ 1405 vma->vm_truncate_count = details->truncate_count; 1406 if (!need_break) 1407 return 0; 1408 } else { 1409 /* Note restart_addr in vma's truncate_count field */ 1410 vma->vm_truncate_count = restart_addr; 1411 if (!need_break) 1412 goto again; 1413 } 1414 1415 spin_unlock(details->i_mmap_lock); 1416 cond_resched(); 1417 spin_lock(details->i_mmap_lock); 1418 return -EINTR; 1419} 1420 1421static inline void unmap_mapping_range_tree(struct prio_tree_root *root, 1422 struct zap_details *details) 1423{ 1424 struct vm_area_struct *vma; 1425 struct prio_tree_iter iter; 1426 pgoff_t vba, vea, zba, zea; 1427 1428restart: 1429 vma_prio_tree_foreach(vma, &iter, root, 1430 details->first_index, details->last_index) { 1431 /* Skip quickly over those we have already dealt with */ 1432 if (vma->vm_truncate_count == details->truncate_count) 1433 continue; 1434 1435 vba = vma->vm_pgoff; 1436 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; 1437 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 1438 zba = details->first_index; 1439 if (zba < vba) 1440 zba = vba; 1441 zea = details->last_index; 1442 if (zea > vea) 1443 zea = vea; 1444 1445 if (unmap_mapping_range_vma(vma, 1446 ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 1447 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 1448 details) < 0) 1449 goto restart; 1450 } 1451} 1452 1453static inline void unmap_mapping_range_list(struct list_head *head, 1454 struct zap_details *details) 1455{ 1456 struct vm_area_struct *vma; 1457 1458 /* 1459 * In nonlinear VMAs there is no correspondence between virtual address 1460 * offset and file offset. So we must perform an exhaustive search 1461 * across *all* the pages in each nonlinear VMA, not just the pages 1462 * whose virtual address lies outside the file truncation point. 1463 */ 1464restart: 1465 list_for_each_entry(vma, head, shared.vm_set.list) { 1466 /* Skip quickly over those we have already dealt with */ 1467 if (vma->vm_truncate_count == details->truncate_count) 1468 continue; 1469 details->nonlinear_vma = vma; 1470 if (unmap_mapping_range_vma(vma, vma->vm_start, 1471 vma->vm_end, details) < 0) 1472 goto restart; 1473 } 1474} 1475 1476/** 1477 * unmap_mapping_range - unmap the portion of all mmaps 1478 * in the specified address_space corresponding to the specified 1479 * page range in the underlying file. 1480 * @mapping: the address space containing mmaps to be unmapped. 1481 * @holebegin: byte in first page to unmap, relative to the start of 1482 * the underlying file. This will be rounded down to a PAGE_SIZE 1483 * boundary. Note that this is different from vmtruncate(), which 1484 * must keep the partial page. In contrast, we must get rid of 1485 * partial pages. 1486 * @holelen: size of prospective hole in bytes. This will be rounded 1487 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 1488 * end of the file. 1489 * @even_cows: 1 when truncating a file, unmap even private COWed pages; 1490 * but 0 when invalidating pagecache, don't throw away private data. 1491 */ 1492void unmap_mapping_range(struct address_space *mapping, 1493 loff_t const holebegin, loff_t const holelen, int even_cows) 1494{ 1495 struct zap_details details; 1496 pgoff_t hba = holebegin >> PAGE_SHIFT; 1497 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1498 1499 /* Check for overflow. */ 1500 if (sizeof(holelen) > sizeof(hlen)) { 1501 long long holeend = 1502 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1503 if (holeend & ~(long long)ULONG_MAX) 1504 hlen = ULONG_MAX - hba + 1; 1505 } 1506 1507 details.check_mapping = even_cows? NULL: mapping; 1508 details.nonlinear_vma = NULL; 1509 details.first_index = hba; 1510 details.last_index = hba + hlen - 1; 1511 if (details.last_index < details.first_index) 1512 details.last_index = ULONG_MAX; 1513 details.i_mmap_lock = &mapping->i_mmap_lock; 1514 1515 spin_lock(&mapping->i_mmap_lock); 1516 1517 /* serialize i_size write against truncate_count write */ 1518 smp_wmb(); 1519 /* Protect against page faults, and endless unmapping loops */ 1520 mapping->truncate_count++; 1521 /* 1522 * For archs where spin_lock has inclusive semantics like ia64 1523 * this smp_mb() will prevent to read pagetable contents 1524 * before the truncate_count increment is visible to 1525 * other cpus. 1526 */ 1527 smp_mb(); 1528 if (unlikely(is_restart_addr(mapping->truncate_count))) { 1529 if (mapping->truncate_count == 0) 1530 reset_vma_truncate_counts(mapping); 1531 mapping->truncate_count++; 1532 } 1533 details.truncate_count = mapping->truncate_count; 1534 1535 if (unlikely(!prio_tree_empty(&mapping->i_mmap))) 1536 unmap_mapping_range_tree(&mapping->i_mmap, &details); 1537 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 1538 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 1539 spin_unlock(&mapping->i_mmap_lock); 1540} 1541EXPORT_SYMBOL(unmap_mapping_range); 1542 1543/* 1544 * Handle all mappings that got truncated by a "truncate()" 1545 * system call. 1546 * 1547 * NOTE! We have to be ready to update the memory sharing 1548 * between the file and the memory map for a potential last 1549 * incomplete page. Ugly, but necessary. 1550 */ 1551int vmtruncate(struct inode * inode, loff_t offset) 1552{ 1553 struct address_space *mapping = inode->i_mapping; 1554 unsigned long limit; 1555 1556 if (inode->i_size < offset) 1557 goto do_expand; 1558 /* 1559 * truncation of in-use swapfiles is disallowed - it would cause 1560 * subsequent swapout to scribble on the now-freed blocks. 1561 */ 1562 if (IS_SWAPFILE(inode)) 1563 goto out_busy; 1564 i_size_write(inode, offset); 1565 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 1566 truncate_inode_pages(mapping, offset); 1567 goto out_truncate; 1568 1569do_expand: 1570 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; 1571 if (limit != RLIM_INFINITY && offset > limit) 1572 goto out_sig; 1573 if (offset > inode->i_sb->s_maxbytes) 1574 goto out_big; 1575 i_size_write(inode, offset); 1576 1577out_truncate: 1578 if (inode->i_op && inode->i_op->truncate) 1579 inode->i_op->truncate(inode); 1580 return 0; 1581out_sig: 1582 send_sig(SIGXFSZ, current, 0); 1583out_big: 1584 return -EFBIG; 1585out_busy: 1586 return -ETXTBSY; 1587} 1588 1589EXPORT_SYMBOL(vmtruncate); 1590 1591/* 1592 * Primitive swap readahead code. We simply read an aligned block of 1593 * (1 << page_cluster) entries in the swap area. This method is chosen 1594 * because it doesn't cost us any seek time. We also make sure to queue 1595 * the 'original' request together with the readahead ones... 1596 * 1597 * This has been extended to use the NUMA policies from the mm triggering 1598 * the readahead. 1599 * 1600 * Caller must hold down_read on the vma->vm_mm if vma is not NULL. 1601 */ 1602void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) 1603{ 1604#ifdef CONFIG_NUMA 1605 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; 1606#endif 1607 int i, num; 1608 struct page *new_page; 1609 unsigned long offset; 1610 1611 /* 1612 * Get the number of handles we should do readahead io to. 1613 */ 1614 num = valid_swaphandles(entry, &offset); 1615 for (i = 0; i < num; offset++, i++) { 1616 /* Ok, do the async read-ahead now */ 1617 new_page = read_swap_cache_async(swp_entry(swp_type(entry), 1618 offset), vma, addr); 1619 if (!new_page) 1620 break; 1621 page_cache_release(new_page); 1622#ifdef CONFIG_NUMA 1623 /* 1624 * Find the next applicable VMA for the NUMA policy. 1625 */ 1626 addr += PAGE_SIZE; 1627 if (addr == 0) 1628 vma = NULL; 1629 if (vma) { 1630 if (addr >= vma->vm_end) { 1631 vma = next_vma; 1632 next_vma = vma ? vma->vm_next : NULL; 1633 } 1634 if (vma && addr < vma->vm_start) 1635 vma = NULL; 1636 } else { 1637 if (next_vma && addr >= next_vma->vm_start) { 1638 vma = next_vma; 1639 next_vma = vma->vm_next; 1640 } 1641 } 1642#endif 1643 } 1644 lru_add_drain(); /* Push any new pages onto the LRU now */ 1645} 1646 1647/* 1648 * We hold the mm semaphore and the page_table_lock on entry and 1649 * should release the pagetable lock on exit.. 1650 */ 1651static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, 1652 unsigned long address, pte_t *page_table, pmd_t *pmd, 1653 int write_access, pte_t orig_pte) 1654{ 1655 struct page *page; 1656 swp_entry_t entry; 1657 pte_t pte; 1658 int ret = VM_FAULT_MINOR; 1659 1660 pte_unmap(page_table); 1661 spin_unlock(&mm->page_table_lock); 1662 1663 entry = pte_to_swp_entry(orig_pte); 1664 page = lookup_swap_cache(entry); 1665 if (!page) { 1666 swapin_readahead(entry, address, vma); 1667 page = read_swap_cache_async(entry, vma, address); 1668 if (!page) { 1669 /* 1670 * Back out if somebody else faulted in this pte while 1671 * we released the page table lock. 1672 */ 1673 spin_lock(&mm->page_table_lock); 1674 page_table = pte_offset_map(pmd, address); 1675 if (likely(pte_same(*page_table, orig_pte))) 1676 ret = VM_FAULT_OOM; 1677 goto unlock; 1678 } 1679 1680 /* Had to read the page from swap area: Major fault */ 1681 ret = VM_FAULT_MAJOR; 1682 inc_page_state(pgmajfault); 1683 grab_swap_token(); 1684 } 1685 1686 mark_page_accessed(page); 1687 lock_page(page); 1688 1689 /* 1690 * Back out if somebody else faulted in this pte while we 1691 * released the page table lock. 1692 */ 1693 spin_lock(&mm->page_table_lock); 1694 page_table = pte_offset_map(pmd, address); 1695 if (unlikely(!pte_same(*page_table, orig_pte))) { 1696 ret = VM_FAULT_MINOR; 1697 goto out_nomap; 1698 } 1699 1700 if (unlikely(!PageUptodate(page))) { 1701 ret = VM_FAULT_SIGBUS; 1702 goto out_nomap; 1703 } 1704 1705 /* The page isn't present yet, go ahead with the fault. */ 1706 1707 inc_mm_counter(mm, anon_rss); 1708 pte = mk_pte(page, vma->vm_page_prot); 1709 if (write_access && can_share_swap_page(page)) { 1710 pte = maybe_mkwrite(pte_mkdirty(pte), vma); 1711 write_access = 0; 1712 } 1713 1714 flush_icache_page(vma, page); 1715 set_pte_at(mm, address, page_table, pte); 1716 page_add_anon_rmap(page, vma, address); 1717 1718 swap_free(entry); 1719 if (vm_swap_full()) 1720 remove_exclusive_swap_page(page); 1721 unlock_page(page); 1722 1723 if (write_access) { 1724 if (do_wp_page(mm, vma, address, 1725 page_table, pmd, pte) == VM_FAULT_OOM) 1726 ret = VM_FAULT_OOM; 1727 goto out; 1728 } 1729 1730 /* No need to invalidate - it was non-present before */ 1731 update_mmu_cache(vma, address, pte); 1732 lazy_mmu_prot_update(pte); 1733unlock: 1734 pte_unmap(page_table); 1735 spin_unlock(&mm->page_table_lock); 1736out: 1737 return ret; 1738out_nomap: 1739 pte_unmap(page_table); 1740 spin_unlock(&mm->page_table_lock); 1741 unlock_page(page); 1742 page_cache_release(page); 1743 return ret; 1744} 1745 1746/* 1747 * We are called with the MM semaphore and page_table_lock 1748 * spinlock held to protect against concurrent faults in 1749 * multithreaded programs. 1750 */ 1751static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 1752 unsigned long address, pte_t *page_table, pmd_t *pmd, 1753 int write_access) 1754{ 1755 pte_t entry; 1756 1757 /* Mapping of ZERO_PAGE - vm_page_prot is readonly */ 1758 entry = mk_pte(ZERO_PAGE(addr), vma->vm_page_prot); 1759 1760 if (write_access) { 1761 struct page *page; 1762 1763 /* Allocate our own private page. */ 1764 pte_unmap(page_table); 1765 spin_unlock(&mm->page_table_lock); 1766 1767 if (unlikely(anon_vma_prepare(vma))) 1768 goto oom; 1769 page = alloc_zeroed_user_highpage(vma, address); 1770 if (!page) 1771 goto oom; 1772 1773 spin_lock(&mm->page_table_lock); 1774 page_table = pte_offset_map(pmd, address); 1775 1776 if (!pte_none(*page_table)) { 1777 page_cache_release(page); 1778 goto unlock; 1779 } 1780 inc_mm_counter(mm, anon_rss); 1781 entry = mk_pte(page, vma->vm_page_prot); 1782 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1783 lru_cache_add_active(page); 1784 SetPageReferenced(page); 1785 page_add_anon_rmap(page, vma, address); 1786 } 1787 1788 set_pte_at(mm, address, page_table, entry); 1789 1790 /* No need to invalidate - it was non-present before */ 1791 update_mmu_cache(vma, address, entry); 1792 lazy_mmu_prot_update(entry); 1793unlock: 1794 pte_unmap(page_table); 1795 spin_unlock(&mm->page_table_lock); 1796 return VM_FAULT_MINOR; 1797oom: 1798 return VM_FAULT_OOM; 1799} 1800 1801/* 1802 * do_no_page() tries to create a new page mapping. It aggressively 1803 * tries to share with existing pages, but makes a separate copy if 1804 * the "write_access" parameter is true in order to avoid the next 1805 * page fault. 1806 * 1807 * As this is called only for pages that do not currently exist, we 1808 * do not need to flush old virtual caches or the TLB. 1809 * 1810 * This is called with the MM semaphore held and the page table 1811 * spinlock held. Exit with the spinlock released. 1812 */ 1813static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 1814 unsigned long address, pte_t *page_table, pmd_t *pmd, 1815 int write_access) 1816{ 1817 struct page *new_page; 1818 struct address_space *mapping = NULL; 1819 pte_t entry; 1820 unsigned int sequence = 0; 1821 int ret = VM_FAULT_MINOR; 1822 int anon = 0; 1823 1824 pte_unmap(page_table); 1825 spin_unlock(&mm->page_table_lock); 1826 1827 if (vma->vm_file) { 1828 mapping = vma->vm_file->f_mapping; 1829 sequence = mapping->truncate_count; 1830 smp_rmb(); /* serializes i_size against truncate_count */ 1831 } 1832retry: 1833 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); 1834 /* 1835 * No smp_rmb is needed here as long as there's a full 1836 * spin_lock/unlock sequence inside the ->nopage callback 1837 * (for the pagecache lookup) that acts as an implicit 1838 * smp_mb() and prevents the i_size read to happen 1839 * after the next truncate_count read. 1840 */ 1841 1842 /* no page was available -- either SIGBUS or OOM */ 1843 if (new_page == NOPAGE_SIGBUS) 1844 return VM_FAULT_SIGBUS; 1845 if (new_page == NOPAGE_OOM) 1846 return VM_FAULT_OOM; 1847 1848 /* 1849 * Should we do an early C-O-W break? 1850 */ 1851 if (write_access && !(vma->vm_flags & VM_SHARED)) { 1852 struct page *page; 1853 1854 if (unlikely(anon_vma_prepare(vma))) 1855 goto oom; 1856 page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1857 if (!page) 1858 goto oom; 1859 copy_user_highpage(page, new_page, address); 1860 page_cache_release(new_page); 1861 new_page = page; 1862 anon = 1; 1863 } 1864 1865 spin_lock(&mm->page_table_lock); 1866 /* 1867 * For a file-backed vma, someone could have truncated or otherwise 1868 * invalidated this page. If unmap_mapping_range got called, 1869 * retry getting the page. 1870 */ 1871 if (mapping && unlikely(sequence != mapping->truncate_count)) { 1872 spin_unlock(&mm->page_table_lock); 1873 page_cache_release(new_page); 1874 cond_resched(); 1875 sequence = mapping->truncate_count; 1876 smp_rmb(); 1877 goto retry; 1878 } 1879 page_table = pte_offset_map(pmd, address); 1880 1881 /* 1882 * This silly early PAGE_DIRTY setting removes a race 1883 * due to the bad i386 page protection. But it's valid 1884 * for other architectures too. 1885 * 1886 * Note that if write_access is true, we either now have 1887 * an exclusive copy of the page, or this is a shared mapping, 1888 * so we can make it writable and dirty to avoid having to 1889 * handle that later. 1890 */ 1891 /* Only go through if we didn't race with anybody else... */ 1892 if (pte_none(*page_table)) { 1893 flush_icache_page(vma, new_page); 1894 entry = mk_pte(new_page, vma->vm_page_prot); 1895 if (write_access) 1896 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1897 set_pte_at(mm, address, page_table, entry); 1898 if (anon) { 1899 inc_mm_counter(mm, anon_rss); 1900 lru_cache_add_active(new_page); 1901 page_add_anon_rmap(new_page, vma, address); 1902 } else if (!PageReserved(new_page)) { 1903 inc_mm_counter(mm, file_rss); 1904 page_add_file_rmap(new_page); 1905 } 1906 } else { 1907 /* One of our sibling threads was faster, back out. */ 1908 page_cache_release(new_page); 1909 goto unlock; 1910 } 1911 1912 /* no need to invalidate: a not-present page shouldn't be cached */ 1913 update_mmu_cache(vma, address, entry); 1914 lazy_mmu_prot_update(entry); 1915unlock: 1916 pte_unmap(page_table); 1917 spin_unlock(&mm->page_table_lock); 1918 return ret; 1919oom: 1920 page_cache_release(new_page); 1921 return VM_FAULT_OOM; 1922} 1923 1924/* 1925 * Fault of a previously existing named mapping. Repopulate the pte 1926 * from the encoded file_pte if possible. This enables swappable 1927 * nonlinear vmas. 1928 */ 1929static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma, 1930 unsigned long address, pte_t *page_table, pmd_t *pmd, 1931 int write_access, pte_t orig_pte) 1932{ 1933 pgoff_t pgoff; 1934 int err; 1935 1936 pte_unmap(page_table); 1937 spin_unlock(&mm->page_table_lock); 1938 1939 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { 1940 /* 1941 * Page table corrupted: show pte and kill process. 1942 */ 1943 pte_ERROR(orig_pte); 1944 return VM_FAULT_OOM; 1945 } 1946 /* We can then assume vm->vm_ops && vma->vm_ops->populate */ 1947 1948 pgoff = pte_to_pgoff(orig_pte); 1949 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, 1950 vma->vm_page_prot, pgoff, 0); 1951 if (err == -ENOMEM) 1952 return VM_FAULT_OOM; 1953 if (err) 1954 return VM_FAULT_SIGBUS; 1955 return VM_FAULT_MAJOR; 1956} 1957 1958/* 1959 * These routines also need to handle stuff like marking pages dirty 1960 * and/or accessed for architectures that don't do it in hardware (most 1961 * RISC architectures). The early dirtying is also good on the i386. 1962 * 1963 * There is also a hook called "update_mmu_cache()" that architectures 1964 * with external mmu caches can use to update those (ie the Sparc or 1965 * PowerPC hashed page tables that act as extended TLBs). 1966 * 1967 * Note the "page_table_lock". It is to protect against kswapd removing 1968 * pages from under us. Note that kswapd only ever _removes_ pages, never 1969 * adds them. As such, once we have noticed that the page is not present, 1970 * we can drop the lock early. 1971 * 1972 * The adding of pages is protected by the MM semaphore (which we hold), 1973 * so we don't need to worry about a page being suddenly been added into 1974 * our VM. 1975 * 1976 * We enter with the pagetable spinlock held, we are supposed to 1977 * release it when done. 1978 */ 1979static inline int handle_pte_fault(struct mm_struct *mm, 1980 struct vm_area_struct *vma, unsigned long address, 1981 pte_t *pte, pmd_t *pmd, int write_access) 1982{ 1983 pte_t entry; 1984 1985 entry = *pte; 1986 if (!pte_present(entry)) { 1987 if (pte_none(entry)) { 1988 if (!vma->vm_ops || !vma->vm_ops->nopage) 1989 return do_anonymous_page(mm, vma, address, 1990 pte, pmd, write_access); 1991 return do_no_page(mm, vma, address, 1992 pte, pmd, write_access); 1993 } 1994 if (pte_file(entry)) 1995 return do_file_page(mm, vma, address, 1996 pte, pmd, write_access, entry); 1997 return do_swap_page(mm, vma, address, 1998 pte, pmd, write_access, entry); 1999 } 2000 2001 if (write_access) { 2002 if (!pte_write(entry)) 2003 return do_wp_page(mm, vma, address, pte, pmd, entry); 2004 entry = pte_mkdirty(entry); 2005 } 2006 entry = pte_mkyoung(entry); 2007 ptep_set_access_flags(vma, address, pte, entry, write_access); 2008 update_mmu_cache(vma, address, entry); 2009 lazy_mmu_prot_update(entry); 2010 pte_unmap(pte); 2011 spin_unlock(&mm->page_table_lock); 2012 return VM_FAULT_MINOR; 2013} 2014 2015/* 2016 * By the time we get here, we already hold the mm semaphore 2017 */ 2018int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, 2019 unsigned long address, int write_access) 2020{ 2021 pgd_t *pgd; 2022 pud_t *pud; 2023 pmd_t *pmd; 2024 pte_t *pte; 2025 2026 __set_current_state(TASK_RUNNING); 2027 2028 inc_page_state(pgfault); 2029 2030 if (unlikely(is_vm_hugetlb_page(vma))) 2031 return hugetlb_fault(mm, vma, address, write_access); 2032 2033 /* 2034 * We need the page table lock to synchronize with kswapd 2035 * and the SMP-safe atomic PTE updates. 2036 */ 2037 pgd = pgd_offset(mm, address); 2038 spin_lock(&mm->page_table_lock); 2039 2040 pud = pud_alloc(mm, pgd, address); 2041 if (!pud) 2042 goto oom; 2043 2044 pmd = pmd_alloc(mm, pud, address); 2045 if (!pmd) 2046 goto oom; 2047 2048 pte = pte_alloc_map(mm, pmd, address); 2049 if (!pte) 2050 goto oom; 2051 2052 return handle_pte_fault(mm, vma, address, pte, pmd, write_access); 2053 2054 oom: 2055 spin_unlock(&mm->page_table_lock); 2056 return VM_FAULT_OOM; 2057} 2058 2059#ifndef __PAGETABLE_PUD_FOLDED 2060/* 2061 * Allocate page upper directory. 2062 * 2063 * We've already handled the fast-path in-line, and we own the 2064 * page table lock. 2065 */ 2066pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 2067{ 2068 pud_t *new; 2069 2070 spin_unlock(&mm->page_table_lock); 2071 new = pud_alloc_one(mm, address); 2072 spin_lock(&mm->page_table_lock); 2073 if (!new) 2074 return NULL; 2075 2076 /* 2077 * Because we dropped the lock, we should re-check the 2078 * entry, as somebody else could have populated it.. 2079 */ 2080 if (pgd_present(*pgd)) { 2081 pud_free(new); 2082 goto out; 2083 } 2084 pgd_populate(mm, pgd, new); 2085 out: 2086 return pud_offset(pgd, address); 2087} 2088#endif /* __PAGETABLE_PUD_FOLDED */ 2089 2090#ifndef __PAGETABLE_PMD_FOLDED 2091/* 2092 * Allocate page middle directory. 2093 * 2094 * We've already handled the fast-path in-line, and we own the 2095 * page table lock. 2096 */ 2097pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 2098{ 2099 pmd_t *new; 2100 2101 spin_unlock(&mm->page_table_lock); 2102 new = pmd_alloc_one(mm, address); 2103 spin_lock(&mm->page_table_lock); 2104 if (!new) 2105 return NULL; 2106 2107 /* 2108 * Because we dropped the lock, we should re-check the 2109 * entry, as somebody else could have populated it.. 2110 */ 2111#ifndef __ARCH_HAS_4LEVEL_HACK 2112 if (pud_present(*pud)) { 2113 pmd_free(new); 2114 goto out; 2115 } 2116 pud_populate(mm, pud, new); 2117#else 2118 if (pgd_present(*pud)) { 2119 pmd_free(new); 2120 goto out; 2121 } 2122 pgd_populate(mm, pud, new); 2123#endif /* __ARCH_HAS_4LEVEL_HACK */ 2124 2125 out: 2126 return pmd_offset(pud, address); 2127} 2128#endif /* __PAGETABLE_PMD_FOLDED */ 2129 2130int make_pages_present(unsigned long addr, unsigned long end) 2131{ 2132 int ret, len, write; 2133 struct vm_area_struct * vma; 2134 2135 vma = find_vma(current->mm, addr); 2136 if (!vma) 2137 return -1; 2138 write = (vma->vm_flags & VM_WRITE) != 0; 2139 if (addr >= end) 2140 BUG(); 2141 if (end > vma->vm_end) 2142 BUG(); 2143 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; 2144 ret = get_user_pages(current, current->mm, addr, 2145 len, write, 0, NULL, NULL); 2146 if (ret < 0) 2147 return ret; 2148 return ret == len ? 0 : -1; 2149} 2150 2151/* 2152 * Map a vmalloc()-space virtual address to the physical page. 2153 */ 2154struct page * vmalloc_to_page(void * vmalloc_addr) 2155{ 2156 unsigned long addr = (unsigned long) vmalloc_addr; 2157 struct page *page = NULL; 2158 pgd_t *pgd = pgd_offset_k(addr); 2159 pud_t *pud; 2160 pmd_t *pmd; 2161 pte_t *ptep, pte; 2162 2163 if (!pgd_none(*pgd)) { 2164 pud = pud_offset(pgd, addr); 2165 if (!pud_none(*pud)) { 2166 pmd = pmd_offset(pud, addr); 2167 if (!pmd_none(*pmd)) { 2168 ptep = pte_offset_map(pmd, addr); 2169 pte = *ptep; 2170 if (pte_present(pte)) 2171 page = pte_page(pte); 2172 pte_unmap(ptep); 2173 } 2174 } 2175 } 2176 return page; 2177} 2178 2179EXPORT_SYMBOL(vmalloc_to_page); 2180 2181/* 2182 * Map a vmalloc()-space virtual address to the physical page frame number. 2183 */ 2184unsigned long vmalloc_to_pfn(void * vmalloc_addr) 2185{ 2186 return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 2187} 2188 2189EXPORT_SYMBOL(vmalloc_to_pfn); 2190 2191/* 2192 * update_mem_hiwater 2193 * - update per process rss and vm high water data 2194 */ 2195void update_mem_hiwater(struct task_struct *tsk) 2196{ 2197 if (tsk->mm) { 2198 unsigned long rss = get_mm_rss(tsk->mm); 2199 2200 if (tsk->mm->hiwater_rss < rss) 2201 tsk->mm->hiwater_rss = rss; 2202 if (tsk->mm->hiwater_vm < tsk->mm->total_vm) 2203 tsk->mm->hiwater_vm = tsk->mm->total_vm; 2204 } 2205} 2206 2207#if !defined(__HAVE_ARCH_GATE_AREA) 2208 2209#if defined(AT_SYSINFO_EHDR) 2210static struct vm_area_struct gate_vma; 2211 2212static int __init gate_vma_init(void) 2213{ 2214 gate_vma.vm_mm = NULL; 2215 gate_vma.vm_start = FIXADDR_USER_START; 2216 gate_vma.vm_end = FIXADDR_USER_END; 2217 gate_vma.vm_page_prot = PAGE_READONLY; 2218 gate_vma.vm_flags = 0; 2219 return 0; 2220} 2221__initcall(gate_vma_init); 2222#endif 2223 2224struct vm_area_struct *get_gate_vma(struct task_struct *tsk) 2225{ 2226#ifdef AT_SYSINFO_EHDR 2227 return &gate_vma; 2228#else 2229 return NULL; 2230#endif 2231} 2232 2233int in_gate_area_no_task(unsigned long addr) 2234{ 2235#ifdef AT_SYSINFO_EHDR 2236 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 2237 return 1; 2238#endif 2239 return 0; 2240} 2241 2242#endif /* __HAVE_ARCH_GATE_AREA */ 2243