memory.c revision a68d2ebc1581a3aec57bd032651e013fa609f530
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_is_full_mm(*tlb)) 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 inc_mm_counter(dst_mm, rss); 401 if (PageAnon(page)) 402 inc_mm_counter(dst_mm, anon_rss); 403 set_pte_at(dst_mm, addr, dst_pte, pte); 404 page_dup_rmap(page); 405} 406 407static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 408 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, 409 unsigned long addr, unsigned long end) 410{ 411 pte_t *src_pte, *dst_pte; 412 unsigned long vm_flags = vma->vm_flags; 413 int progress; 414 415again: 416 dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr); 417 if (!dst_pte) 418 return -ENOMEM; 419 src_pte = pte_offset_map_nested(src_pmd, addr); 420 421 progress = 0; 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 && (need_resched() || 429 need_lockbreak(&src_mm->page_table_lock) || 430 need_lockbreak(&dst_mm->page_table_lock))) 431 break; 432 if (pte_none(*src_pte)) { 433 progress++; 434 continue; 435 } 436 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vm_flags, addr); 437 progress += 8; 438 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); 439 spin_unlock(&src_mm->page_table_lock); 440 441 pte_unmap_nested(src_pte - 1); 442 pte_unmap(dst_pte - 1); 443 cond_resched_lock(&dst_mm->page_table_lock); 444 if (addr != end) 445 goto again; 446 return 0; 447} 448 449static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 450 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, 451 unsigned long addr, unsigned long end) 452{ 453 pmd_t *src_pmd, *dst_pmd; 454 unsigned long next; 455 456 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); 457 if (!dst_pmd) 458 return -ENOMEM; 459 src_pmd = pmd_offset(src_pud, addr); 460 do { 461 next = pmd_addr_end(addr, end); 462 if (pmd_none_or_clear_bad(src_pmd)) 463 continue; 464 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, 465 vma, addr, next)) 466 return -ENOMEM; 467 } while (dst_pmd++, src_pmd++, addr = next, addr != end); 468 return 0; 469} 470 471static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 472 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, 473 unsigned long addr, unsigned long end) 474{ 475 pud_t *src_pud, *dst_pud; 476 unsigned long next; 477 478 dst_pud = pud_alloc(dst_mm, dst_pgd, addr); 479 if (!dst_pud) 480 return -ENOMEM; 481 src_pud = pud_offset(src_pgd, addr); 482 do { 483 next = pud_addr_end(addr, end); 484 if (pud_none_or_clear_bad(src_pud)) 485 continue; 486 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, 487 vma, addr, next)) 488 return -ENOMEM; 489 } while (dst_pud++, src_pud++, addr = next, addr != end); 490 return 0; 491} 492 493int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, 494 struct vm_area_struct *vma) 495{ 496 pgd_t *src_pgd, *dst_pgd; 497 unsigned long next; 498 unsigned long addr = vma->vm_start; 499 unsigned long end = vma->vm_end; 500 501 if (is_vm_hugetlb_page(vma)) 502 return copy_hugetlb_page_range(dst_mm, src_mm, vma); 503 504 dst_pgd = pgd_offset(dst_mm, addr); 505 src_pgd = pgd_offset(src_mm, addr); 506 do { 507 next = pgd_addr_end(addr, end); 508 if (pgd_none_or_clear_bad(src_pgd)) 509 continue; 510 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, 511 vma, addr, next)) 512 return -ENOMEM; 513 } while (dst_pgd++, src_pgd++, addr = next, addr != end); 514 return 0; 515} 516 517static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, 518 unsigned long addr, unsigned long end, 519 struct zap_details *details) 520{ 521 pte_t *pte; 522 523 pte = pte_offset_map(pmd, addr); 524 do { 525 pte_t ptent = *pte; 526 if (pte_none(ptent)) 527 continue; 528 if (pte_present(ptent)) { 529 struct page *page = NULL; 530 unsigned long pfn = pte_pfn(ptent); 531 if (pfn_valid(pfn)) { 532 page = pfn_to_page(pfn); 533 if (PageReserved(page)) 534 page = NULL; 535 } 536 if (unlikely(details) && page) { 537 /* 538 * unmap_shared_mapping_pages() wants to 539 * invalidate cache without truncating: 540 * unmap shared but keep private pages. 541 */ 542 if (details->check_mapping && 543 details->check_mapping != page->mapping) 544 continue; 545 /* 546 * Each page->index must be checked when 547 * invalidating or truncating nonlinear. 548 */ 549 if (details->nonlinear_vma && 550 (page->index < details->first_index || 551 page->index > details->last_index)) 552 continue; 553 } 554 ptent = ptep_get_and_clear(tlb->mm, addr, pte); 555 tlb_remove_tlb_entry(tlb, pte, addr); 556 if (unlikely(!page)) 557 continue; 558 if (unlikely(details) && details->nonlinear_vma 559 && linear_page_index(details->nonlinear_vma, 560 addr) != page->index) 561 set_pte_at(tlb->mm, addr, pte, 562 pgoff_to_pte(page->index)); 563 if (pte_dirty(ptent)) 564 set_page_dirty(page); 565 if (PageAnon(page)) 566 dec_mm_counter(tlb->mm, anon_rss); 567 else if (pte_young(ptent)) 568 mark_page_accessed(page); 569 tlb->freed++; 570 page_remove_rmap(page); 571 tlb_remove_page(tlb, page); 572 continue; 573 } 574 /* 575 * If details->check_mapping, we leave swap entries; 576 * if details->nonlinear_vma, we leave file entries. 577 */ 578 if (unlikely(details)) 579 continue; 580 if (!pte_file(ptent)) 581 free_swap_and_cache(pte_to_swp_entry(ptent)); 582 pte_clear(tlb->mm, addr, pte); 583 } while (pte++, addr += PAGE_SIZE, addr != end); 584 pte_unmap(pte - 1); 585} 586 587static inline void zap_pmd_range(struct mmu_gather *tlb, pud_t *pud, 588 unsigned long addr, unsigned long end, 589 struct zap_details *details) 590{ 591 pmd_t *pmd; 592 unsigned long next; 593 594 pmd = pmd_offset(pud, addr); 595 do { 596 next = pmd_addr_end(addr, end); 597 if (pmd_none_or_clear_bad(pmd)) 598 continue; 599 zap_pte_range(tlb, pmd, addr, next, details); 600 } while (pmd++, addr = next, addr != end); 601} 602 603static inline void zap_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 604 unsigned long addr, unsigned long end, 605 struct zap_details *details) 606{ 607 pud_t *pud; 608 unsigned long next; 609 610 pud = pud_offset(pgd, addr); 611 do { 612 next = pud_addr_end(addr, end); 613 if (pud_none_or_clear_bad(pud)) 614 continue; 615 zap_pmd_range(tlb, pud, addr, next, details); 616 } while (pud++, addr = next, addr != end); 617} 618 619static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma, 620 unsigned long addr, unsigned long end, 621 struct zap_details *details) 622{ 623 pgd_t *pgd; 624 unsigned long next; 625 626 if (details && !details->check_mapping && !details->nonlinear_vma) 627 details = NULL; 628 629 BUG_ON(addr >= end); 630 tlb_start_vma(tlb, vma); 631 pgd = pgd_offset(vma->vm_mm, addr); 632 do { 633 next = pgd_addr_end(addr, end); 634 if (pgd_none_or_clear_bad(pgd)) 635 continue; 636 zap_pud_range(tlb, pgd, addr, next, details); 637 } while (pgd++, addr = next, addr != end); 638 tlb_end_vma(tlb, vma); 639} 640 641#ifdef CONFIG_PREEMPT 642# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) 643#else 644/* No preempt: go for improved straight-line efficiency */ 645# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) 646#endif 647 648/** 649 * unmap_vmas - unmap a range of memory covered by a list of vma's 650 * @tlbp: address of the caller's struct mmu_gather 651 * @mm: the controlling mm_struct 652 * @vma: the starting vma 653 * @start_addr: virtual address at which to start unmapping 654 * @end_addr: virtual address at which to end unmapping 655 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here 656 * @details: details of nonlinear truncation or shared cache invalidation 657 * 658 * Returns the end address of the unmapping (restart addr if interrupted). 659 * 660 * Unmap all pages in the vma list. Called under page_table_lock. 661 * 662 * We aim to not hold page_table_lock for too long (for scheduling latency 663 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to 664 * return the ending mmu_gather to the caller. 665 * 666 * Only addresses between `start' and `end' will be unmapped. 667 * 668 * The VMA list must be sorted in ascending virtual address order. 669 * 670 * unmap_vmas() assumes that the caller will flush the whole unmapped address 671 * range after unmap_vmas() returns. So the only responsibility here is to 672 * ensure that any thus-far unmapped pages are flushed before unmap_vmas() 673 * drops the lock and schedules. 674 */ 675unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, 676 struct vm_area_struct *vma, unsigned long start_addr, 677 unsigned long end_addr, unsigned long *nr_accounted, 678 struct zap_details *details) 679{ 680 unsigned long zap_bytes = ZAP_BLOCK_SIZE; 681 unsigned long tlb_start = 0; /* For tlb_finish_mmu */ 682 int tlb_start_valid = 0; 683 unsigned long start = start_addr; 684 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; 685 int fullmm = tlb_is_full_mm(*tlbp); 686 687 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { 688 unsigned long end; 689 690 start = max(vma->vm_start, start_addr); 691 if (start >= vma->vm_end) 692 continue; 693 end = min(vma->vm_end, end_addr); 694 if (end <= vma->vm_start) 695 continue; 696 697 if (vma->vm_flags & VM_ACCOUNT) 698 *nr_accounted += (end - start) >> PAGE_SHIFT; 699 700 while (start != end) { 701 unsigned long block; 702 703 if (!tlb_start_valid) { 704 tlb_start = start; 705 tlb_start_valid = 1; 706 } 707 708 if (is_vm_hugetlb_page(vma)) { 709 block = end - start; 710 unmap_hugepage_range(vma, start, end); 711 } else { 712 block = min(zap_bytes, end - start); 713 unmap_page_range(*tlbp, vma, start, 714 start + block, details); 715 } 716 717 start += block; 718 zap_bytes -= block; 719 if ((long)zap_bytes > 0) 720 continue; 721 722 tlb_finish_mmu(*tlbp, tlb_start, start); 723 724 if (need_resched() || 725 need_lockbreak(&mm->page_table_lock) || 726 (i_mmap_lock && need_lockbreak(i_mmap_lock))) { 727 if (i_mmap_lock) { 728 /* must reset count of rss freed */ 729 *tlbp = tlb_gather_mmu(mm, fullmm); 730 goto out; 731 } 732 spin_unlock(&mm->page_table_lock); 733 cond_resched(); 734 spin_lock(&mm->page_table_lock); 735 } 736 737 *tlbp = tlb_gather_mmu(mm, fullmm); 738 tlb_start_valid = 0; 739 zap_bytes = ZAP_BLOCK_SIZE; 740 } 741 } 742out: 743 return start; /* which is now the end (or restart) address */ 744} 745 746/** 747 * zap_page_range - remove user pages in a given range 748 * @vma: vm_area_struct holding the applicable pages 749 * @address: starting address of pages to zap 750 * @size: number of bytes to zap 751 * @details: details of nonlinear truncation or shared cache invalidation 752 */ 753unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, 754 unsigned long size, struct zap_details *details) 755{ 756 struct mm_struct *mm = vma->vm_mm; 757 struct mmu_gather *tlb; 758 unsigned long end = address + size; 759 unsigned long nr_accounted = 0; 760 761 if (is_vm_hugetlb_page(vma)) { 762 zap_hugepage_range(vma, address, size); 763 return end; 764 } 765 766 lru_add_drain(); 767 spin_lock(&mm->page_table_lock); 768 tlb = tlb_gather_mmu(mm, 0); 769 end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details); 770 tlb_finish_mmu(tlb, address, end); 771 spin_unlock(&mm->page_table_lock); 772 return end; 773} 774 775/* 776 * Do a quick page-table lookup for a single page. 777 * mm->page_table_lock must be held. 778 */ 779static struct page *__follow_page(struct mm_struct *mm, unsigned long address, 780 int read, int write, int accessed) 781{ 782 pgd_t *pgd; 783 pud_t *pud; 784 pmd_t *pmd; 785 pte_t *ptep, pte; 786 unsigned long pfn; 787 struct page *page; 788 789 page = follow_huge_addr(mm, address, write); 790 if (! IS_ERR(page)) 791 return page; 792 793 pgd = pgd_offset(mm, address); 794 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 795 goto out; 796 797 pud = pud_offset(pgd, address); 798 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 799 goto out; 800 801 pmd = pmd_offset(pud, address); 802 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 803 goto out; 804 if (pmd_huge(*pmd)) 805 return follow_huge_pmd(mm, address, pmd, write); 806 807 ptep = pte_offset_map(pmd, address); 808 if (!ptep) 809 goto out; 810 811 pte = *ptep; 812 pte_unmap(ptep); 813 if (pte_present(pte)) { 814 if (write && !pte_write(pte)) 815 goto out; 816 if (read && !pte_read(pte)) 817 goto out; 818 pfn = pte_pfn(pte); 819 if (pfn_valid(pfn)) { 820 page = pfn_to_page(pfn); 821 if (accessed) { 822 if (write && !pte_dirty(pte) &&!PageDirty(page)) 823 set_page_dirty(page); 824 mark_page_accessed(page); 825 } 826 return page; 827 } 828 } 829 830out: 831 return NULL; 832} 833 834inline struct page * 835follow_page(struct mm_struct *mm, unsigned long address, int write) 836{ 837 return __follow_page(mm, address, 0, write, 1); 838} 839 840/* 841 * check_user_page_readable() can be called frm niterrupt context by oprofile, 842 * so we need to avoid taking any non-irq-safe locks 843 */ 844int check_user_page_readable(struct mm_struct *mm, unsigned long address) 845{ 846 return __follow_page(mm, address, 1, 0, 0) != NULL; 847} 848EXPORT_SYMBOL(check_user_page_readable); 849 850static inline int 851untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma, 852 unsigned long address) 853{ 854 pgd_t *pgd; 855 pud_t *pud; 856 pmd_t *pmd; 857 858 /* Check if the vma is for an anonymous mapping. */ 859 if (vma->vm_ops && vma->vm_ops->nopage) 860 return 0; 861 862 /* Check if page directory entry exists. */ 863 pgd = pgd_offset(mm, address); 864 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 865 return 1; 866 867 pud = pud_offset(pgd, address); 868 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 869 return 1; 870 871 /* Check if page middle directory entry exists. */ 872 pmd = pmd_offset(pud, address); 873 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 874 return 1; 875 876 /* There is a pte slot for 'address' in 'mm'. */ 877 return 0; 878} 879 880int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 881 unsigned long start, int len, int write, int force, 882 struct page **pages, struct vm_area_struct **vmas) 883{ 884 int i; 885 unsigned int flags; 886 887 /* 888 * Require read or write permissions. 889 * If 'force' is set, we only require the "MAY" flags. 890 */ 891 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 892 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 893 i = 0; 894 895 do { 896 struct vm_area_struct * vma; 897 898 vma = find_extend_vma(mm, start); 899 if (!vma && in_gate_area(tsk, start)) { 900 unsigned long pg = start & PAGE_MASK; 901 struct vm_area_struct *gate_vma = get_gate_vma(tsk); 902 pgd_t *pgd; 903 pud_t *pud; 904 pmd_t *pmd; 905 pte_t *pte; 906 if (write) /* user gate pages are read-only */ 907 return i ? : -EFAULT; 908 if (pg > TASK_SIZE) 909 pgd = pgd_offset_k(pg); 910 else 911 pgd = pgd_offset_gate(mm, pg); 912 BUG_ON(pgd_none(*pgd)); 913 pud = pud_offset(pgd, pg); 914 BUG_ON(pud_none(*pud)); 915 pmd = pmd_offset(pud, pg); 916 if (pmd_none(*pmd)) 917 return i ? : -EFAULT; 918 pte = pte_offset_map(pmd, pg); 919 if (pte_none(*pte)) { 920 pte_unmap(pte); 921 return i ? : -EFAULT; 922 } 923 if (pages) { 924 pages[i] = pte_page(*pte); 925 get_page(pages[i]); 926 } 927 pte_unmap(pte); 928 if (vmas) 929 vmas[i] = gate_vma; 930 i++; 931 start += PAGE_SIZE; 932 len--; 933 continue; 934 } 935 936 if (!vma || (vma->vm_flags & VM_IO) 937 || !(flags & vma->vm_flags)) 938 return i ? : -EFAULT; 939 940 if (is_vm_hugetlb_page(vma)) { 941 i = follow_hugetlb_page(mm, vma, pages, vmas, 942 &start, &len, i); 943 continue; 944 } 945 spin_lock(&mm->page_table_lock); 946 do { 947 int write_access = write; 948 struct page *page; 949 950 cond_resched_lock(&mm->page_table_lock); 951 while (!(page = follow_page(mm, start, write_access))) { 952 int ret; 953 954 /* 955 * Shortcut for anonymous pages. We don't want 956 * to force the creation of pages tables for 957 * insanely big anonymously mapped areas that 958 * nobody touched so far. This is important 959 * for doing a core dump for these mappings. 960 */ 961 if (!write && untouched_anonymous_page(mm,vma,start)) { 962 page = ZERO_PAGE(start); 963 break; 964 } 965 spin_unlock(&mm->page_table_lock); 966 ret = __handle_mm_fault(mm, vma, start, write_access); 967 968 /* 969 * The VM_FAULT_WRITE bit tells us that do_wp_page has 970 * broken COW when necessary, even if maybe_mkwrite 971 * decided not to set pte_write. We can thus safely do 972 * subsequent page lookups as if they were reads. 973 */ 974 if (ret & VM_FAULT_WRITE) 975 write_access = 0; 976 977 switch (ret & ~VM_FAULT_WRITE) { 978 case VM_FAULT_MINOR: 979 tsk->min_flt++; 980 break; 981 case VM_FAULT_MAJOR: 982 tsk->maj_flt++; 983 break; 984 case VM_FAULT_SIGBUS: 985 return i ? i : -EFAULT; 986 case VM_FAULT_OOM: 987 return i ? i : -ENOMEM; 988 default: 989 BUG(); 990 } 991 spin_lock(&mm->page_table_lock); 992 } 993 if (pages) { 994 pages[i] = page; 995 flush_dcache_page(page); 996 if (!PageReserved(page)) 997 page_cache_get(page); 998 } 999 if (vmas) 1000 vmas[i] = vma; 1001 i++; 1002 start += PAGE_SIZE; 1003 len--; 1004 } while (len && start < vma->vm_end); 1005 spin_unlock(&mm->page_table_lock); 1006 } while (len); 1007 return i; 1008} 1009EXPORT_SYMBOL(get_user_pages); 1010 1011static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1012 unsigned long addr, unsigned long end, pgprot_t prot) 1013{ 1014 pte_t *pte; 1015 1016 pte = pte_alloc_map(mm, pmd, addr); 1017 if (!pte) 1018 return -ENOMEM; 1019 do { 1020 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(addr), prot)); 1021 BUG_ON(!pte_none(*pte)); 1022 set_pte_at(mm, addr, pte, zero_pte); 1023 } while (pte++, addr += PAGE_SIZE, addr != end); 1024 pte_unmap(pte - 1); 1025 return 0; 1026} 1027 1028static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, 1029 unsigned long addr, unsigned long end, pgprot_t prot) 1030{ 1031 pmd_t *pmd; 1032 unsigned long next; 1033 1034 pmd = pmd_alloc(mm, pud, addr); 1035 if (!pmd) 1036 return -ENOMEM; 1037 do { 1038 next = pmd_addr_end(addr, end); 1039 if (zeromap_pte_range(mm, pmd, addr, next, prot)) 1040 return -ENOMEM; 1041 } while (pmd++, addr = next, addr != end); 1042 return 0; 1043} 1044 1045static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1046 unsigned long addr, unsigned long end, pgprot_t prot) 1047{ 1048 pud_t *pud; 1049 unsigned long next; 1050 1051 pud = pud_alloc(mm, pgd, addr); 1052 if (!pud) 1053 return -ENOMEM; 1054 do { 1055 next = pud_addr_end(addr, end); 1056 if (zeromap_pmd_range(mm, pud, addr, next, prot)) 1057 return -ENOMEM; 1058 } while (pud++, addr = next, addr != end); 1059 return 0; 1060} 1061 1062int zeromap_page_range(struct vm_area_struct *vma, 1063 unsigned long addr, unsigned long size, pgprot_t prot) 1064{ 1065 pgd_t *pgd; 1066 unsigned long next; 1067 unsigned long end = addr + size; 1068 struct mm_struct *mm = vma->vm_mm; 1069 int err; 1070 1071 BUG_ON(addr >= end); 1072 pgd = pgd_offset(mm, addr); 1073 flush_cache_range(vma, addr, end); 1074 spin_lock(&mm->page_table_lock); 1075 do { 1076 next = pgd_addr_end(addr, end); 1077 err = zeromap_pud_range(mm, pgd, addr, next, prot); 1078 if (err) 1079 break; 1080 } while (pgd++, addr = next, addr != end); 1081 spin_unlock(&mm->page_table_lock); 1082 return err; 1083} 1084 1085/* 1086 * maps a range of physical memory into the requested pages. the old 1087 * mappings are removed. any references to nonexistent pages results 1088 * in null mappings (currently treated as "copy-on-access") 1089 */ 1090static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1091 unsigned long addr, unsigned long end, 1092 unsigned long pfn, pgprot_t prot) 1093{ 1094 pte_t *pte; 1095 1096 pte = pte_alloc_map(mm, pmd, addr); 1097 if (!pte) 1098 return -ENOMEM; 1099 do { 1100 BUG_ON(!pte_none(*pte)); 1101 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn))) 1102 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); 1103 pfn++; 1104 } while (pte++, addr += PAGE_SIZE, addr != end); 1105 pte_unmap(pte - 1); 1106 return 0; 1107} 1108 1109static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 1110 unsigned long addr, unsigned long end, 1111 unsigned long pfn, pgprot_t prot) 1112{ 1113 pmd_t *pmd; 1114 unsigned long next; 1115 1116 pfn -= addr >> PAGE_SHIFT; 1117 pmd = pmd_alloc(mm, pud, addr); 1118 if (!pmd) 1119 return -ENOMEM; 1120 do { 1121 next = pmd_addr_end(addr, end); 1122 if (remap_pte_range(mm, pmd, addr, next, 1123 pfn + (addr >> PAGE_SHIFT), prot)) 1124 return -ENOMEM; 1125 } while (pmd++, addr = next, addr != end); 1126 return 0; 1127} 1128 1129static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1130 unsigned long addr, unsigned long end, 1131 unsigned long pfn, pgprot_t prot) 1132{ 1133 pud_t *pud; 1134 unsigned long next; 1135 1136 pfn -= addr >> PAGE_SHIFT; 1137 pud = pud_alloc(mm, pgd, addr); 1138 if (!pud) 1139 return -ENOMEM; 1140 do { 1141 next = pud_addr_end(addr, end); 1142 if (remap_pmd_range(mm, pud, addr, next, 1143 pfn + (addr >> PAGE_SHIFT), prot)) 1144 return -ENOMEM; 1145 } while (pud++, addr = next, addr != end); 1146 return 0; 1147} 1148 1149/* Note: this is only safe if the mm semaphore is held when called. */ 1150int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 1151 unsigned long pfn, unsigned long size, pgprot_t prot) 1152{ 1153 pgd_t *pgd; 1154 unsigned long next; 1155 unsigned long end = addr + PAGE_ALIGN(size); 1156 struct mm_struct *mm = vma->vm_mm; 1157 int err; 1158 1159 /* 1160 * Physically remapped pages are special. Tell the 1161 * rest of the world about it: 1162 * VM_IO tells people not to look at these pages 1163 * (accesses can have side effects). 1164 * VM_RESERVED tells swapout not to try to touch 1165 * this region. 1166 */ 1167 vma->vm_flags |= VM_IO | VM_RESERVED; 1168 1169 BUG_ON(addr >= end); 1170 pfn -= addr >> PAGE_SHIFT; 1171 pgd = pgd_offset(mm, addr); 1172 flush_cache_range(vma, addr, end); 1173 spin_lock(&mm->page_table_lock); 1174 do { 1175 next = pgd_addr_end(addr, end); 1176 err = remap_pud_range(mm, pgd, addr, next, 1177 pfn + (addr >> PAGE_SHIFT), prot); 1178 if (err) 1179 break; 1180 } while (pgd++, addr = next, addr != end); 1181 spin_unlock(&mm->page_table_lock); 1182 return err; 1183} 1184EXPORT_SYMBOL(remap_pfn_range); 1185 1186/* 1187 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when 1188 * servicing faults for write access. In the normal case, do always want 1189 * pte_mkwrite. But get_user_pages can cause write faults for mappings 1190 * that do not have writing enabled, when used by access_process_vm. 1191 */ 1192static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 1193{ 1194 if (likely(vma->vm_flags & VM_WRITE)) 1195 pte = pte_mkwrite(pte); 1196 return pte; 1197} 1198 1199/* 1200 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock 1201 */ 1202static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address, 1203 pte_t *page_table) 1204{ 1205 pte_t entry; 1206 1207 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)), 1208 vma); 1209 ptep_establish(vma, address, page_table, entry); 1210 update_mmu_cache(vma, address, entry); 1211 lazy_mmu_prot_update(entry); 1212} 1213 1214/* 1215 * This routine handles present pages, when users try to write 1216 * to a shared page. It is done by copying the page to a new address 1217 * and decrementing the shared-page counter for the old page. 1218 * 1219 * Goto-purists beware: the only reason for goto's here is that it results 1220 * in better assembly code.. The "default" path will see no jumps at all. 1221 * 1222 * Note that this routine assumes that the protection checks have been 1223 * done by the caller (the low-level page fault routine in most cases). 1224 * Thus we can safely just mark it writable once we've done any necessary 1225 * COW. 1226 * 1227 * We also mark the page dirty at this point even though the page will 1228 * change only once the write actually happens. This avoids a few races, 1229 * and potentially makes it more efficient. 1230 * 1231 * We hold the mm semaphore and the page_table_lock on entry and exit 1232 * with the page_table_lock released. 1233 */ 1234static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma, 1235 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte) 1236{ 1237 struct page *old_page, *new_page; 1238 unsigned long pfn = pte_pfn(pte); 1239 pte_t entry; 1240 int ret; 1241 1242 if (unlikely(!pfn_valid(pfn))) { 1243 /* 1244 * This should really halt the system so it can be debugged or 1245 * at least the kernel stops what it's doing before it corrupts 1246 * data, but for the moment just pretend this is OOM. 1247 */ 1248 pte_unmap(page_table); 1249 printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n", 1250 address); 1251 spin_unlock(&mm->page_table_lock); 1252 return VM_FAULT_OOM; 1253 } 1254 old_page = pfn_to_page(pfn); 1255 1256 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { 1257 int reuse = can_share_swap_page(old_page); 1258 unlock_page(old_page); 1259 if (reuse) { 1260 flush_cache_page(vma, address, pfn); 1261 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)), 1262 vma); 1263 ptep_set_access_flags(vma, address, page_table, entry, 1); 1264 update_mmu_cache(vma, address, entry); 1265 lazy_mmu_prot_update(entry); 1266 pte_unmap(page_table); 1267 spin_unlock(&mm->page_table_lock); 1268 return VM_FAULT_MINOR|VM_FAULT_WRITE; 1269 } 1270 } 1271 pte_unmap(page_table); 1272 1273 /* 1274 * Ok, we need to copy. Oh, well.. 1275 */ 1276 if (!PageReserved(old_page)) 1277 page_cache_get(old_page); 1278 spin_unlock(&mm->page_table_lock); 1279 1280 if (unlikely(anon_vma_prepare(vma))) 1281 goto no_new_page; 1282 if (old_page == ZERO_PAGE(address)) { 1283 new_page = alloc_zeroed_user_highpage(vma, address); 1284 if (!new_page) 1285 goto no_new_page; 1286 } else { 1287 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1288 if (!new_page) 1289 goto no_new_page; 1290 copy_user_highpage(new_page, old_page, address); 1291 } 1292 /* 1293 * Re-check the pte - we dropped the lock 1294 */ 1295 ret = VM_FAULT_MINOR; 1296 spin_lock(&mm->page_table_lock); 1297 page_table = pte_offset_map(pmd, address); 1298 if (likely(pte_same(*page_table, pte))) { 1299 if (PageAnon(old_page)) 1300 dec_mm_counter(mm, anon_rss); 1301 if (PageReserved(old_page)) 1302 inc_mm_counter(mm, rss); 1303 else 1304 page_remove_rmap(old_page); 1305 flush_cache_page(vma, address, pfn); 1306 break_cow(vma, new_page, address, page_table); 1307 lru_cache_add_active(new_page); 1308 page_add_anon_rmap(new_page, vma, address); 1309 1310 /* Free the old page.. */ 1311 new_page = old_page; 1312 ret |= VM_FAULT_WRITE; 1313 } 1314 pte_unmap(page_table); 1315 page_cache_release(new_page); 1316 page_cache_release(old_page); 1317 spin_unlock(&mm->page_table_lock); 1318 return ret; 1319 1320no_new_page: 1321 page_cache_release(old_page); 1322 return VM_FAULT_OOM; 1323} 1324 1325/* 1326 * Helper functions for unmap_mapping_range(). 1327 * 1328 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ 1329 * 1330 * We have to restart searching the prio_tree whenever we drop the lock, 1331 * since the iterator is only valid while the lock is held, and anyway 1332 * a later vma might be split and reinserted earlier while lock dropped. 1333 * 1334 * The list of nonlinear vmas could be handled more efficiently, using 1335 * a placeholder, but handle it in the same way until a need is shown. 1336 * It is important to search the prio_tree before nonlinear list: a vma 1337 * may become nonlinear and be shifted from prio_tree to nonlinear list 1338 * while the lock is dropped; but never shifted from list to prio_tree. 1339 * 1340 * In order to make forward progress despite restarting the search, 1341 * vm_truncate_count is used to mark a vma as now dealt with, so we can 1342 * quickly skip it next time around. Since the prio_tree search only 1343 * shows us those vmas affected by unmapping the range in question, we 1344 * can't efficiently keep all vmas in step with mapping->truncate_count: 1345 * so instead reset them all whenever it wraps back to 0 (then go to 1). 1346 * mapping->truncate_count and vma->vm_truncate_count are protected by 1347 * i_mmap_lock. 1348 * 1349 * In order to make forward progress despite repeatedly restarting some 1350 * large vma, note the restart_addr from unmap_vmas when it breaks out: 1351 * and restart from that address when we reach that vma again. It might 1352 * have been split or merged, shrunk or extended, but never shifted: so 1353 * restart_addr remains valid so long as it remains in the vma's range. 1354 * unmap_mapping_range forces truncate_count to leap over page-aligned 1355 * values so we can save vma's restart_addr in its truncate_count field. 1356 */ 1357#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) 1358 1359static void reset_vma_truncate_counts(struct address_space *mapping) 1360{ 1361 struct vm_area_struct *vma; 1362 struct prio_tree_iter iter; 1363 1364 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) 1365 vma->vm_truncate_count = 0; 1366 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) 1367 vma->vm_truncate_count = 0; 1368} 1369 1370static int unmap_mapping_range_vma(struct vm_area_struct *vma, 1371 unsigned long start_addr, unsigned long end_addr, 1372 struct zap_details *details) 1373{ 1374 unsigned long restart_addr; 1375 int need_break; 1376 1377again: 1378 restart_addr = vma->vm_truncate_count; 1379 if (is_restart_addr(restart_addr) && start_addr < restart_addr) { 1380 start_addr = restart_addr; 1381 if (start_addr >= end_addr) { 1382 /* Top of vma has been split off since last time */ 1383 vma->vm_truncate_count = details->truncate_count; 1384 return 0; 1385 } 1386 } 1387 1388 restart_addr = zap_page_range(vma, start_addr, 1389 end_addr - start_addr, details); 1390 1391 /* 1392 * We cannot rely on the break test in unmap_vmas: 1393 * on the one hand, we don't want to restart our loop 1394 * just because that broke out for the page_table_lock; 1395 * on the other hand, it does no test when vma is small. 1396 */ 1397 need_break = need_resched() || 1398 need_lockbreak(details->i_mmap_lock); 1399 1400 if (restart_addr >= end_addr) { 1401 /* We have now completed this vma: mark it so */ 1402 vma->vm_truncate_count = details->truncate_count; 1403 if (!need_break) 1404 return 0; 1405 } else { 1406 /* Note restart_addr in vma's truncate_count field */ 1407 vma->vm_truncate_count = restart_addr; 1408 if (!need_break) 1409 goto again; 1410 } 1411 1412 spin_unlock(details->i_mmap_lock); 1413 cond_resched(); 1414 spin_lock(details->i_mmap_lock); 1415 return -EINTR; 1416} 1417 1418static inline void unmap_mapping_range_tree(struct prio_tree_root *root, 1419 struct zap_details *details) 1420{ 1421 struct vm_area_struct *vma; 1422 struct prio_tree_iter iter; 1423 pgoff_t vba, vea, zba, zea; 1424 1425restart: 1426 vma_prio_tree_foreach(vma, &iter, root, 1427 details->first_index, details->last_index) { 1428 /* Skip quickly over those we have already dealt with */ 1429 if (vma->vm_truncate_count == details->truncate_count) 1430 continue; 1431 1432 vba = vma->vm_pgoff; 1433 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; 1434 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 1435 zba = details->first_index; 1436 if (zba < vba) 1437 zba = vba; 1438 zea = details->last_index; 1439 if (zea > vea) 1440 zea = vea; 1441 1442 if (unmap_mapping_range_vma(vma, 1443 ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 1444 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 1445 details) < 0) 1446 goto restart; 1447 } 1448} 1449 1450static inline void unmap_mapping_range_list(struct list_head *head, 1451 struct zap_details *details) 1452{ 1453 struct vm_area_struct *vma; 1454 1455 /* 1456 * In nonlinear VMAs there is no correspondence between virtual address 1457 * offset and file offset. So we must perform an exhaustive search 1458 * across *all* the pages in each nonlinear VMA, not just the pages 1459 * whose virtual address lies outside the file truncation point. 1460 */ 1461restart: 1462 list_for_each_entry(vma, head, shared.vm_set.list) { 1463 /* Skip quickly over those we have already dealt with */ 1464 if (vma->vm_truncate_count == details->truncate_count) 1465 continue; 1466 details->nonlinear_vma = vma; 1467 if (unmap_mapping_range_vma(vma, vma->vm_start, 1468 vma->vm_end, details) < 0) 1469 goto restart; 1470 } 1471} 1472 1473/** 1474 * unmap_mapping_range - unmap the portion of all mmaps 1475 * in the specified address_space corresponding to the specified 1476 * page range in the underlying file. 1477 * @mapping: the address space containing mmaps to be unmapped. 1478 * @holebegin: byte in first page to unmap, relative to the start of 1479 * the underlying file. This will be rounded down to a PAGE_SIZE 1480 * boundary. Note that this is different from vmtruncate(), which 1481 * must keep the partial page. In contrast, we must get rid of 1482 * partial pages. 1483 * @holelen: size of prospective hole in bytes. This will be rounded 1484 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 1485 * end of the file. 1486 * @even_cows: 1 when truncating a file, unmap even private COWed pages; 1487 * but 0 when invalidating pagecache, don't throw away private data. 1488 */ 1489void unmap_mapping_range(struct address_space *mapping, 1490 loff_t const holebegin, loff_t const holelen, int even_cows) 1491{ 1492 struct zap_details details; 1493 pgoff_t hba = holebegin >> PAGE_SHIFT; 1494 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1495 1496 /* Check for overflow. */ 1497 if (sizeof(holelen) > sizeof(hlen)) { 1498 long long holeend = 1499 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1500 if (holeend & ~(long long)ULONG_MAX) 1501 hlen = ULONG_MAX - hba + 1; 1502 } 1503 1504 details.check_mapping = even_cows? NULL: mapping; 1505 details.nonlinear_vma = NULL; 1506 details.first_index = hba; 1507 details.last_index = hba + hlen - 1; 1508 if (details.last_index < details.first_index) 1509 details.last_index = ULONG_MAX; 1510 details.i_mmap_lock = &mapping->i_mmap_lock; 1511 1512 spin_lock(&mapping->i_mmap_lock); 1513 1514 /* serialize i_size write against truncate_count write */ 1515 smp_wmb(); 1516 /* Protect against page faults, and endless unmapping loops */ 1517 mapping->truncate_count++; 1518 /* 1519 * For archs where spin_lock has inclusive semantics like ia64 1520 * this smp_mb() will prevent to read pagetable contents 1521 * before the truncate_count increment is visible to 1522 * other cpus. 1523 */ 1524 smp_mb(); 1525 if (unlikely(is_restart_addr(mapping->truncate_count))) { 1526 if (mapping->truncate_count == 0) 1527 reset_vma_truncate_counts(mapping); 1528 mapping->truncate_count++; 1529 } 1530 details.truncate_count = mapping->truncate_count; 1531 1532 if (unlikely(!prio_tree_empty(&mapping->i_mmap))) 1533 unmap_mapping_range_tree(&mapping->i_mmap, &details); 1534 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 1535 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 1536 spin_unlock(&mapping->i_mmap_lock); 1537} 1538EXPORT_SYMBOL(unmap_mapping_range); 1539 1540/* 1541 * Handle all mappings that got truncated by a "truncate()" 1542 * system call. 1543 * 1544 * NOTE! We have to be ready to update the memory sharing 1545 * between the file and the memory map for a potential last 1546 * incomplete page. Ugly, but necessary. 1547 */ 1548int vmtruncate(struct inode * inode, loff_t offset) 1549{ 1550 struct address_space *mapping = inode->i_mapping; 1551 unsigned long limit; 1552 1553 if (inode->i_size < offset) 1554 goto do_expand; 1555 /* 1556 * truncation of in-use swapfiles is disallowed - it would cause 1557 * subsequent swapout to scribble on the now-freed blocks. 1558 */ 1559 if (IS_SWAPFILE(inode)) 1560 goto out_busy; 1561 i_size_write(inode, offset); 1562 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 1563 truncate_inode_pages(mapping, offset); 1564 goto out_truncate; 1565 1566do_expand: 1567 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; 1568 if (limit != RLIM_INFINITY && offset > limit) 1569 goto out_sig; 1570 if (offset > inode->i_sb->s_maxbytes) 1571 goto out_big; 1572 i_size_write(inode, offset); 1573 1574out_truncate: 1575 if (inode->i_op && inode->i_op->truncate) 1576 inode->i_op->truncate(inode); 1577 return 0; 1578out_sig: 1579 send_sig(SIGXFSZ, current, 0); 1580out_big: 1581 return -EFBIG; 1582out_busy: 1583 return -ETXTBSY; 1584} 1585 1586EXPORT_SYMBOL(vmtruncate); 1587 1588/* 1589 * Primitive swap readahead code. We simply read an aligned block of 1590 * (1 << page_cluster) entries in the swap area. This method is chosen 1591 * because it doesn't cost us any seek time. We also make sure to queue 1592 * the 'original' request together with the readahead ones... 1593 * 1594 * This has been extended to use the NUMA policies from the mm triggering 1595 * the readahead. 1596 * 1597 * Caller must hold down_read on the vma->vm_mm if vma is not NULL. 1598 */ 1599void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) 1600{ 1601#ifdef CONFIG_NUMA 1602 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; 1603#endif 1604 int i, num; 1605 struct page *new_page; 1606 unsigned long offset; 1607 1608 /* 1609 * Get the number of handles we should do readahead io to. 1610 */ 1611 num = valid_swaphandles(entry, &offset); 1612 for (i = 0; i < num; offset++, i++) { 1613 /* Ok, do the async read-ahead now */ 1614 new_page = read_swap_cache_async(swp_entry(swp_type(entry), 1615 offset), vma, addr); 1616 if (!new_page) 1617 break; 1618 page_cache_release(new_page); 1619#ifdef CONFIG_NUMA 1620 /* 1621 * Find the next applicable VMA for the NUMA policy. 1622 */ 1623 addr += PAGE_SIZE; 1624 if (addr == 0) 1625 vma = NULL; 1626 if (vma) { 1627 if (addr >= vma->vm_end) { 1628 vma = next_vma; 1629 next_vma = vma ? vma->vm_next : NULL; 1630 } 1631 if (vma && addr < vma->vm_start) 1632 vma = NULL; 1633 } else { 1634 if (next_vma && addr >= next_vma->vm_start) { 1635 vma = next_vma; 1636 next_vma = vma->vm_next; 1637 } 1638 } 1639#endif 1640 } 1641 lru_add_drain(); /* Push any new pages onto the LRU now */ 1642} 1643 1644/* 1645 * We hold the mm semaphore and the page_table_lock on entry and 1646 * should release the pagetable lock on exit.. 1647 */ 1648static int do_swap_page(struct mm_struct * mm, 1649 struct vm_area_struct * vma, unsigned long address, 1650 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access) 1651{ 1652 struct page *page; 1653 swp_entry_t entry = pte_to_swp_entry(orig_pte); 1654 pte_t pte; 1655 int ret = VM_FAULT_MINOR; 1656 1657 pte_unmap(page_table); 1658 spin_unlock(&mm->page_table_lock); 1659 page = lookup_swap_cache(entry); 1660 if (!page) { 1661 swapin_readahead(entry, address, vma); 1662 page = read_swap_cache_async(entry, vma, address); 1663 if (!page) { 1664 /* 1665 * Back out if somebody else faulted in this pte while 1666 * we released the page table lock. 1667 */ 1668 spin_lock(&mm->page_table_lock); 1669 page_table = pte_offset_map(pmd, address); 1670 if (likely(pte_same(*page_table, orig_pte))) 1671 ret = VM_FAULT_OOM; 1672 else 1673 ret = VM_FAULT_MINOR; 1674 pte_unmap(page_table); 1675 spin_unlock(&mm->page_table_lock); 1676 goto out; 1677 } 1678 1679 /* Had to read the page from swap area: Major fault */ 1680 ret = VM_FAULT_MAJOR; 1681 inc_page_state(pgmajfault); 1682 grab_swap_token(); 1683 } 1684 1685 mark_page_accessed(page); 1686 lock_page(page); 1687 1688 /* 1689 * Back out if somebody else faulted in this pte while we 1690 * released the page table lock. 1691 */ 1692 spin_lock(&mm->page_table_lock); 1693 page_table = pte_offset_map(pmd, address); 1694 if (unlikely(!pte_same(*page_table, orig_pte))) { 1695 ret = VM_FAULT_MINOR; 1696 goto out_nomap; 1697 } 1698 1699 if (unlikely(!PageUptodate(page))) { 1700 ret = VM_FAULT_SIGBUS; 1701 goto out_nomap; 1702 } 1703 1704 /* The page isn't present yet, go ahead with the fault. */ 1705 1706 inc_mm_counter(mm, rss); 1707 pte = mk_pte(page, vma->vm_page_prot); 1708 if (write_access && can_share_swap_page(page)) { 1709 pte = maybe_mkwrite(pte_mkdirty(pte), vma); 1710 write_access = 0; 1711 } 1712 1713 flush_icache_page(vma, page); 1714 set_pte_at(mm, address, page_table, pte); 1715 page_add_anon_rmap(page, vma, address); 1716 1717 swap_free(entry); 1718 if (vm_swap_full()) 1719 remove_exclusive_swap_page(page); 1720 unlock_page(page); 1721 1722 if (write_access) { 1723 if (do_wp_page(mm, vma, address, 1724 page_table, pmd, pte) == VM_FAULT_OOM) 1725 ret = VM_FAULT_OOM; 1726 goto out; 1727 } 1728 1729 /* No need to invalidate - it was non-present before */ 1730 update_mmu_cache(vma, address, pte); 1731 lazy_mmu_prot_update(pte); 1732 pte_unmap(page_table); 1733 spin_unlock(&mm->page_table_lock); 1734out: 1735 return ret; 1736out_nomap: 1737 pte_unmap(page_table); 1738 spin_unlock(&mm->page_table_lock); 1739 unlock_page(page); 1740 page_cache_release(page); 1741 goto out; 1742} 1743 1744/* 1745 * We are called with the MM semaphore and page_table_lock 1746 * spinlock held to protect against concurrent faults in 1747 * multithreaded programs. 1748 */ 1749static int 1750do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 1751 pte_t *page_table, pmd_t *pmd, int write_access, 1752 unsigned long addr) 1753{ 1754 pte_t entry; 1755 struct page * page = ZERO_PAGE(addr); 1756 1757 /* Read-only mapping of ZERO_PAGE. */ 1758 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot)); 1759 1760 /* ..except if it's a write access */ 1761 if (write_access) { 1762 /* Allocate our own private page. */ 1763 pte_unmap(page_table); 1764 spin_unlock(&mm->page_table_lock); 1765 1766 if (unlikely(anon_vma_prepare(vma))) 1767 goto no_mem; 1768 page = alloc_zeroed_user_highpage(vma, addr); 1769 if (!page) 1770 goto no_mem; 1771 1772 spin_lock(&mm->page_table_lock); 1773 page_table = pte_offset_map(pmd, addr); 1774 1775 if (!pte_none(*page_table)) { 1776 pte_unmap(page_table); 1777 page_cache_release(page); 1778 spin_unlock(&mm->page_table_lock); 1779 goto out; 1780 } 1781 inc_mm_counter(mm, rss); 1782 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page, 1783 vma->vm_page_prot)), 1784 vma); 1785 lru_cache_add_active(page); 1786 SetPageReferenced(page); 1787 page_add_anon_rmap(page, vma, addr); 1788 } 1789 1790 set_pte_at(mm, addr, page_table, entry); 1791 pte_unmap(page_table); 1792 1793 /* No need to invalidate - it was non-present before */ 1794 update_mmu_cache(vma, addr, entry); 1795 lazy_mmu_prot_update(entry); 1796 spin_unlock(&mm->page_table_lock); 1797out: 1798 return VM_FAULT_MINOR; 1799no_mem: 1800 return VM_FAULT_OOM; 1801} 1802 1803/* 1804 * do_no_page() tries to create a new page mapping. It aggressively 1805 * tries to share with existing pages, but makes a separate copy if 1806 * the "write_access" parameter is true in order to avoid the next 1807 * page fault. 1808 * 1809 * As this is called only for pages that do not currently exist, we 1810 * do not need to flush old virtual caches or the TLB. 1811 * 1812 * This is called with the MM semaphore held and the page table 1813 * spinlock held. Exit with the spinlock released. 1814 */ 1815static int 1816do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 1817 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd) 1818{ 1819 struct page * new_page; 1820 struct address_space *mapping = NULL; 1821 pte_t entry; 1822 unsigned int sequence = 0; 1823 int ret = VM_FAULT_MINOR; 1824 int anon = 0; 1825 1826 if (!vma->vm_ops || !vma->vm_ops->nopage) 1827 return do_anonymous_page(mm, vma, page_table, 1828 pmd, write_access, address); 1829 pte_unmap(page_table); 1830 spin_unlock(&mm->page_table_lock); 1831 1832 if (vma->vm_file) { 1833 mapping = vma->vm_file->f_mapping; 1834 sequence = mapping->truncate_count; 1835 smp_rmb(); /* serializes i_size against truncate_count */ 1836 } 1837retry: 1838 cond_resched(); 1839 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); 1840 /* 1841 * No smp_rmb is needed here as long as there's a full 1842 * spin_lock/unlock sequence inside the ->nopage callback 1843 * (for the pagecache lookup) that acts as an implicit 1844 * smp_mb() and prevents the i_size read to happen 1845 * after the next truncate_count read. 1846 */ 1847 1848 /* no page was available -- either SIGBUS or OOM */ 1849 if (new_page == NOPAGE_SIGBUS) 1850 return VM_FAULT_SIGBUS; 1851 if (new_page == NOPAGE_OOM) 1852 return VM_FAULT_OOM; 1853 1854 /* 1855 * Should we do an early C-O-W break? 1856 */ 1857 if (write_access && !(vma->vm_flags & VM_SHARED)) { 1858 struct page *page; 1859 1860 if (unlikely(anon_vma_prepare(vma))) 1861 goto oom; 1862 page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1863 if (!page) 1864 goto oom; 1865 copy_user_highpage(page, new_page, address); 1866 page_cache_release(new_page); 1867 new_page = page; 1868 anon = 1; 1869 } 1870 1871 spin_lock(&mm->page_table_lock); 1872 /* 1873 * For a file-backed vma, someone could have truncated or otherwise 1874 * invalidated this page. If unmap_mapping_range got called, 1875 * retry getting the page. 1876 */ 1877 if (mapping && unlikely(sequence != mapping->truncate_count)) { 1878 sequence = mapping->truncate_count; 1879 spin_unlock(&mm->page_table_lock); 1880 page_cache_release(new_page); 1881 goto retry; 1882 } 1883 page_table = pte_offset_map(pmd, address); 1884 1885 /* 1886 * This silly early PAGE_DIRTY setting removes a race 1887 * due to the bad i386 page protection. But it's valid 1888 * for other architectures too. 1889 * 1890 * Note that if write_access is true, we either now have 1891 * an exclusive copy of the page, or this is a shared mapping, 1892 * so we can make it writable and dirty to avoid having to 1893 * handle that later. 1894 */ 1895 /* Only go through if we didn't race with anybody else... */ 1896 if (pte_none(*page_table)) { 1897 if (!PageReserved(new_page)) 1898 inc_mm_counter(mm, rss); 1899 1900 flush_icache_page(vma, new_page); 1901 entry = mk_pte(new_page, vma->vm_page_prot); 1902 if (write_access) 1903 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1904 set_pte_at(mm, address, page_table, entry); 1905 if (anon) { 1906 lru_cache_add_active(new_page); 1907 page_add_anon_rmap(new_page, vma, address); 1908 } else 1909 page_add_file_rmap(new_page); 1910 pte_unmap(page_table); 1911 } else { 1912 /* One of our sibling threads was faster, back out. */ 1913 pte_unmap(page_table); 1914 page_cache_release(new_page); 1915 spin_unlock(&mm->page_table_lock); 1916 goto out; 1917 } 1918 1919 /* no need to invalidate: a not-present page shouldn't be cached */ 1920 update_mmu_cache(vma, address, entry); 1921 lazy_mmu_prot_update(entry); 1922 spin_unlock(&mm->page_table_lock); 1923out: 1924 return ret; 1925oom: 1926 page_cache_release(new_page); 1927 ret = VM_FAULT_OOM; 1928 goto out; 1929} 1930 1931/* 1932 * Fault of a previously existing named mapping. Repopulate the pte 1933 * from the encoded file_pte if possible. This enables swappable 1934 * nonlinear vmas. 1935 */ 1936static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma, 1937 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd) 1938{ 1939 unsigned long pgoff; 1940 int err; 1941 1942 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage); 1943 /* 1944 * Fall back to the linear mapping if the fs does not support 1945 * ->populate: 1946 */ 1947 if (!vma->vm_ops || !vma->vm_ops->populate || 1948 (write_access && !(vma->vm_flags & VM_SHARED))) { 1949 pte_clear(mm, address, pte); 1950 return do_no_page(mm, vma, address, write_access, pte, pmd); 1951 } 1952 1953 pgoff = pte_to_pgoff(*pte); 1954 1955 pte_unmap(pte); 1956 spin_unlock(&mm->page_table_lock); 1957 1958 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0); 1959 if (err == -ENOMEM) 1960 return VM_FAULT_OOM; 1961 if (err) 1962 return VM_FAULT_SIGBUS; 1963 return VM_FAULT_MAJOR; 1964} 1965 1966/* 1967 * These routines also need to handle stuff like marking pages dirty 1968 * and/or accessed for architectures that don't do it in hardware (most 1969 * RISC architectures). The early dirtying is also good on the i386. 1970 * 1971 * There is also a hook called "update_mmu_cache()" that architectures 1972 * with external mmu caches can use to update those (ie the Sparc or 1973 * PowerPC hashed page tables that act as extended TLBs). 1974 * 1975 * Note the "page_table_lock". It is to protect against kswapd removing 1976 * pages from under us. Note that kswapd only ever _removes_ pages, never 1977 * adds them. As such, once we have noticed that the page is not present, 1978 * we can drop the lock early. 1979 * 1980 * The adding of pages is protected by the MM semaphore (which we hold), 1981 * so we don't need to worry about a page being suddenly been added into 1982 * our VM. 1983 * 1984 * We enter with the pagetable spinlock held, we are supposed to 1985 * release it when done. 1986 */ 1987static inline int handle_pte_fault(struct mm_struct *mm, 1988 struct vm_area_struct * vma, unsigned long address, 1989 int write_access, pte_t *pte, pmd_t *pmd) 1990{ 1991 pte_t entry; 1992 1993 entry = *pte; 1994 if (!pte_present(entry)) { 1995 /* 1996 * If it truly wasn't present, we know that kswapd 1997 * and the PTE updates will not touch it later. So 1998 * drop the lock. 1999 */ 2000 if (pte_none(entry)) 2001 return do_no_page(mm, vma, address, write_access, pte, pmd); 2002 if (pte_file(entry)) 2003 return do_file_page(mm, vma, address, write_access, pte, pmd); 2004 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access); 2005 } 2006 2007 if (write_access) { 2008 if (!pte_write(entry)) 2009 return do_wp_page(mm, vma, address, pte, pmd, entry); 2010 entry = pte_mkdirty(entry); 2011 } 2012 entry = pte_mkyoung(entry); 2013 ptep_set_access_flags(vma, address, pte, entry, write_access); 2014 update_mmu_cache(vma, address, entry); 2015 lazy_mmu_prot_update(entry); 2016 pte_unmap(pte); 2017 spin_unlock(&mm->page_table_lock); 2018 return VM_FAULT_MINOR; 2019} 2020 2021/* 2022 * By the time we get here, we already hold the mm semaphore 2023 */ 2024int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma, 2025 unsigned long address, int write_access) 2026{ 2027 pgd_t *pgd; 2028 pud_t *pud; 2029 pmd_t *pmd; 2030 pte_t *pte; 2031 2032 __set_current_state(TASK_RUNNING); 2033 2034 inc_page_state(pgfault); 2035 2036 if (is_vm_hugetlb_page(vma)) 2037 return VM_FAULT_SIGBUS; /* mapping truncation does this. */ 2038 2039 /* 2040 * We need the page table lock to synchronize with kswapd 2041 * and the SMP-safe atomic PTE updates. 2042 */ 2043 pgd = pgd_offset(mm, address); 2044 spin_lock(&mm->page_table_lock); 2045 2046 pud = pud_alloc(mm, pgd, address); 2047 if (!pud) 2048 goto oom; 2049 2050 pmd = pmd_alloc(mm, pud, address); 2051 if (!pmd) 2052 goto oom; 2053 2054 pte = pte_alloc_map(mm, pmd, address); 2055 if (!pte) 2056 goto oom; 2057 2058 return handle_pte_fault(mm, vma, address, write_access, pte, pmd); 2059 2060 oom: 2061 spin_unlock(&mm->page_table_lock); 2062 return VM_FAULT_OOM; 2063} 2064 2065#ifndef __PAGETABLE_PUD_FOLDED 2066/* 2067 * Allocate page upper directory. 2068 * 2069 * We've already handled the fast-path in-line, and we own the 2070 * page table lock. 2071 */ 2072pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 2073{ 2074 pud_t *new; 2075 2076 spin_unlock(&mm->page_table_lock); 2077 new = pud_alloc_one(mm, address); 2078 spin_lock(&mm->page_table_lock); 2079 if (!new) 2080 return NULL; 2081 2082 /* 2083 * Because we dropped the lock, we should re-check the 2084 * entry, as somebody else could have populated it.. 2085 */ 2086 if (pgd_present(*pgd)) { 2087 pud_free(new); 2088 goto out; 2089 } 2090 pgd_populate(mm, pgd, new); 2091 out: 2092 return pud_offset(pgd, address); 2093} 2094#endif /* __PAGETABLE_PUD_FOLDED */ 2095 2096#ifndef __PAGETABLE_PMD_FOLDED 2097/* 2098 * Allocate page middle directory. 2099 * 2100 * We've already handled the fast-path in-line, and we own the 2101 * page table lock. 2102 */ 2103pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 2104{ 2105 pmd_t *new; 2106 2107 spin_unlock(&mm->page_table_lock); 2108 new = pmd_alloc_one(mm, address); 2109 spin_lock(&mm->page_table_lock); 2110 if (!new) 2111 return NULL; 2112 2113 /* 2114 * Because we dropped the lock, we should re-check the 2115 * entry, as somebody else could have populated it.. 2116 */ 2117#ifndef __ARCH_HAS_4LEVEL_HACK 2118 if (pud_present(*pud)) { 2119 pmd_free(new); 2120 goto out; 2121 } 2122 pud_populate(mm, pud, new); 2123#else 2124 if (pgd_present(*pud)) { 2125 pmd_free(new); 2126 goto out; 2127 } 2128 pgd_populate(mm, pud, new); 2129#endif /* __ARCH_HAS_4LEVEL_HACK */ 2130 2131 out: 2132 return pmd_offset(pud, address); 2133} 2134#endif /* __PAGETABLE_PMD_FOLDED */ 2135 2136int make_pages_present(unsigned long addr, unsigned long end) 2137{ 2138 int ret, len, write; 2139 struct vm_area_struct * vma; 2140 2141 vma = find_vma(current->mm, addr); 2142 if (!vma) 2143 return -1; 2144 write = (vma->vm_flags & VM_WRITE) != 0; 2145 if (addr >= end) 2146 BUG(); 2147 if (end > vma->vm_end) 2148 BUG(); 2149 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; 2150 ret = get_user_pages(current, current->mm, addr, 2151 len, write, 0, NULL, NULL); 2152 if (ret < 0) 2153 return ret; 2154 return ret == len ? 0 : -1; 2155} 2156 2157/* 2158 * Map a vmalloc()-space virtual address to the physical page. 2159 */ 2160struct page * vmalloc_to_page(void * vmalloc_addr) 2161{ 2162 unsigned long addr = (unsigned long) vmalloc_addr; 2163 struct page *page = NULL; 2164 pgd_t *pgd = pgd_offset_k(addr); 2165 pud_t *pud; 2166 pmd_t *pmd; 2167 pte_t *ptep, pte; 2168 2169 if (!pgd_none(*pgd)) { 2170 pud = pud_offset(pgd, addr); 2171 if (!pud_none(*pud)) { 2172 pmd = pmd_offset(pud, addr); 2173 if (!pmd_none(*pmd)) { 2174 ptep = pte_offset_map(pmd, addr); 2175 pte = *ptep; 2176 if (pte_present(pte)) 2177 page = pte_page(pte); 2178 pte_unmap(ptep); 2179 } 2180 } 2181 } 2182 return page; 2183} 2184 2185EXPORT_SYMBOL(vmalloc_to_page); 2186 2187/* 2188 * Map a vmalloc()-space virtual address to the physical page frame number. 2189 */ 2190unsigned long vmalloc_to_pfn(void * vmalloc_addr) 2191{ 2192 return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 2193} 2194 2195EXPORT_SYMBOL(vmalloc_to_pfn); 2196 2197/* 2198 * update_mem_hiwater 2199 * - update per process rss and vm high water data 2200 */ 2201void update_mem_hiwater(struct task_struct *tsk) 2202{ 2203 if (tsk->mm) { 2204 unsigned long rss = get_mm_counter(tsk->mm, rss); 2205 2206 if (tsk->mm->hiwater_rss < rss) 2207 tsk->mm->hiwater_rss = rss; 2208 if (tsk->mm->hiwater_vm < tsk->mm->total_vm) 2209 tsk->mm->hiwater_vm = tsk->mm->total_vm; 2210 } 2211} 2212 2213#if !defined(__HAVE_ARCH_GATE_AREA) 2214 2215#if defined(AT_SYSINFO_EHDR) 2216struct vm_area_struct gate_vma; 2217 2218static int __init gate_vma_init(void) 2219{ 2220 gate_vma.vm_mm = NULL; 2221 gate_vma.vm_start = FIXADDR_USER_START; 2222 gate_vma.vm_end = FIXADDR_USER_END; 2223 gate_vma.vm_page_prot = PAGE_READONLY; 2224 gate_vma.vm_flags = 0; 2225 return 0; 2226} 2227__initcall(gate_vma_init); 2228#endif 2229 2230struct vm_area_struct *get_gate_vma(struct task_struct *tsk) 2231{ 2232#ifdef AT_SYSINFO_EHDR 2233 return &gate_vma; 2234#else 2235 return NULL; 2236#endif 2237} 2238 2239int in_gate_area_no_task(unsigned long addr) 2240{ 2241#ifdef AT_SYSINFO_EHDR 2242 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 2243 return 1; 2244#endif 2245 return 0; 2246} 2247 2248#endif /* __HAVE_ARCH_GATE_AREA */ 2249