memory.c revision d41dee369bff3b9dcb6328d4d822926c28cc2594
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 * 780__follow_page(struct mm_struct *mm, unsigned long address, int read, int write) 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 (write && !pte_dirty(pte) && !PageDirty(page)) 822 set_page_dirty(page); 823 mark_page_accessed(page); 824 return page; 825 } 826 } 827 828out: 829 return NULL; 830} 831 832struct page * 833follow_page(struct mm_struct *mm, unsigned long address, int write) 834{ 835 return __follow_page(mm, address, /*read*/0, write); 836} 837 838int 839check_user_page_readable(struct mm_struct *mm, unsigned long address) 840{ 841 return __follow_page(mm, address, /*read*/1, /*write*/0) != NULL; 842} 843EXPORT_SYMBOL(check_user_page_readable); 844 845static inline int 846untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma, 847 unsigned long address) 848{ 849 pgd_t *pgd; 850 pud_t *pud; 851 pmd_t *pmd; 852 853 /* Check if the vma is for an anonymous mapping. */ 854 if (vma->vm_ops && vma->vm_ops->nopage) 855 return 0; 856 857 /* Check if page directory entry exists. */ 858 pgd = pgd_offset(mm, address); 859 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) 860 return 1; 861 862 pud = pud_offset(pgd, address); 863 if (pud_none(*pud) || unlikely(pud_bad(*pud))) 864 return 1; 865 866 /* Check if page middle directory entry exists. */ 867 pmd = pmd_offset(pud, address); 868 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) 869 return 1; 870 871 /* There is a pte slot for 'address' in 'mm'. */ 872 return 0; 873} 874 875int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 876 unsigned long start, int len, int write, int force, 877 struct page **pages, struct vm_area_struct **vmas) 878{ 879 int i; 880 unsigned int flags; 881 882 /* 883 * Require read or write permissions. 884 * If 'force' is set, we only require the "MAY" flags. 885 */ 886 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); 887 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); 888 i = 0; 889 890 do { 891 struct vm_area_struct * vma; 892 893 vma = find_extend_vma(mm, start); 894 if (!vma && in_gate_area(tsk, start)) { 895 unsigned long pg = start & PAGE_MASK; 896 struct vm_area_struct *gate_vma = get_gate_vma(tsk); 897 pgd_t *pgd; 898 pud_t *pud; 899 pmd_t *pmd; 900 pte_t *pte; 901 if (write) /* user gate pages are read-only */ 902 return i ? : -EFAULT; 903 if (pg > TASK_SIZE) 904 pgd = pgd_offset_k(pg); 905 else 906 pgd = pgd_offset_gate(mm, pg); 907 BUG_ON(pgd_none(*pgd)); 908 pud = pud_offset(pgd, pg); 909 BUG_ON(pud_none(*pud)); 910 pmd = pmd_offset(pud, pg); 911 BUG_ON(pmd_none(*pmd)); 912 pte = pte_offset_map(pmd, pg); 913 BUG_ON(pte_none(*pte)); 914 if (pages) { 915 pages[i] = pte_page(*pte); 916 get_page(pages[i]); 917 } 918 pte_unmap(pte); 919 if (vmas) 920 vmas[i] = gate_vma; 921 i++; 922 start += PAGE_SIZE; 923 len--; 924 continue; 925 } 926 927 if (!vma || (vma->vm_flags & VM_IO) 928 || !(flags & vma->vm_flags)) 929 return i ? : -EFAULT; 930 931 if (is_vm_hugetlb_page(vma)) { 932 i = follow_hugetlb_page(mm, vma, pages, vmas, 933 &start, &len, i); 934 continue; 935 } 936 spin_lock(&mm->page_table_lock); 937 do { 938 struct page *page; 939 int lookup_write = write; 940 941 cond_resched_lock(&mm->page_table_lock); 942 while (!(page = follow_page(mm, start, lookup_write))) { 943 /* 944 * Shortcut for anonymous pages. We don't want 945 * to force the creation of pages tables for 946 * insanely big anonymously mapped areas that 947 * nobody touched so far. This is important 948 * for doing a core dump for these mappings. 949 */ 950 if (!lookup_write && 951 untouched_anonymous_page(mm,vma,start)) { 952 page = ZERO_PAGE(start); 953 break; 954 } 955 spin_unlock(&mm->page_table_lock); 956 switch (handle_mm_fault(mm,vma,start,write)) { 957 case VM_FAULT_MINOR: 958 tsk->min_flt++; 959 break; 960 case VM_FAULT_MAJOR: 961 tsk->maj_flt++; 962 break; 963 case VM_FAULT_SIGBUS: 964 return i ? i : -EFAULT; 965 case VM_FAULT_OOM: 966 return i ? i : -ENOMEM; 967 default: 968 BUG(); 969 } 970 /* 971 * Now that we have performed a write fault 972 * and surely no longer have a shared page we 973 * shouldn't write, we shouldn't ignore an 974 * unwritable page in the page table if 975 * we are forcing write access. 976 */ 977 lookup_write = write && !force; 978 spin_lock(&mm->page_table_lock); 979 } 980 if (pages) { 981 pages[i] = page; 982 flush_dcache_page(page); 983 if (!PageReserved(page)) 984 page_cache_get(page); 985 } 986 if (vmas) 987 vmas[i] = vma; 988 i++; 989 start += PAGE_SIZE; 990 len--; 991 } while (len && start < vma->vm_end); 992 spin_unlock(&mm->page_table_lock); 993 } while (len); 994 return i; 995} 996EXPORT_SYMBOL(get_user_pages); 997 998static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, 999 unsigned long addr, unsigned long end, pgprot_t prot) 1000{ 1001 pte_t *pte; 1002 1003 pte = pte_alloc_map(mm, pmd, addr); 1004 if (!pte) 1005 return -ENOMEM; 1006 do { 1007 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(addr), prot)); 1008 BUG_ON(!pte_none(*pte)); 1009 set_pte_at(mm, addr, pte, zero_pte); 1010 } while (pte++, addr += PAGE_SIZE, addr != end); 1011 pte_unmap(pte - 1); 1012 return 0; 1013} 1014 1015static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, 1016 unsigned long addr, unsigned long end, pgprot_t prot) 1017{ 1018 pmd_t *pmd; 1019 unsigned long next; 1020 1021 pmd = pmd_alloc(mm, pud, addr); 1022 if (!pmd) 1023 return -ENOMEM; 1024 do { 1025 next = pmd_addr_end(addr, end); 1026 if (zeromap_pte_range(mm, pmd, addr, next, prot)) 1027 return -ENOMEM; 1028 } while (pmd++, addr = next, addr != end); 1029 return 0; 1030} 1031 1032static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1033 unsigned long addr, unsigned long end, pgprot_t prot) 1034{ 1035 pud_t *pud; 1036 unsigned long next; 1037 1038 pud = pud_alloc(mm, pgd, addr); 1039 if (!pud) 1040 return -ENOMEM; 1041 do { 1042 next = pud_addr_end(addr, end); 1043 if (zeromap_pmd_range(mm, pud, addr, next, prot)) 1044 return -ENOMEM; 1045 } while (pud++, addr = next, addr != end); 1046 return 0; 1047} 1048 1049int zeromap_page_range(struct vm_area_struct *vma, 1050 unsigned long addr, unsigned long size, pgprot_t prot) 1051{ 1052 pgd_t *pgd; 1053 unsigned long next; 1054 unsigned long end = addr + size; 1055 struct mm_struct *mm = vma->vm_mm; 1056 int err; 1057 1058 BUG_ON(addr >= end); 1059 pgd = pgd_offset(mm, addr); 1060 flush_cache_range(vma, addr, end); 1061 spin_lock(&mm->page_table_lock); 1062 do { 1063 next = pgd_addr_end(addr, end); 1064 err = zeromap_pud_range(mm, pgd, addr, next, prot); 1065 if (err) 1066 break; 1067 } while (pgd++, addr = next, addr != end); 1068 spin_unlock(&mm->page_table_lock); 1069 return err; 1070} 1071 1072/* 1073 * maps a range of physical memory into the requested pages. the old 1074 * mappings are removed. any references to nonexistent pages results 1075 * in null mappings (currently treated as "copy-on-access") 1076 */ 1077static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, 1078 unsigned long addr, unsigned long end, 1079 unsigned long pfn, pgprot_t prot) 1080{ 1081 pte_t *pte; 1082 1083 pte = pte_alloc_map(mm, pmd, addr); 1084 if (!pte) 1085 return -ENOMEM; 1086 do { 1087 BUG_ON(!pte_none(*pte)); 1088 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn))) 1089 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); 1090 pfn++; 1091 } while (pte++, addr += PAGE_SIZE, addr != end); 1092 pte_unmap(pte - 1); 1093 return 0; 1094} 1095 1096static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, 1097 unsigned long addr, unsigned long end, 1098 unsigned long pfn, pgprot_t prot) 1099{ 1100 pmd_t *pmd; 1101 unsigned long next; 1102 1103 pfn -= addr >> PAGE_SHIFT; 1104 pmd = pmd_alloc(mm, pud, addr); 1105 if (!pmd) 1106 return -ENOMEM; 1107 do { 1108 next = pmd_addr_end(addr, end); 1109 if (remap_pte_range(mm, pmd, addr, next, 1110 pfn + (addr >> PAGE_SHIFT), prot)) 1111 return -ENOMEM; 1112 } while (pmd++, addr = next, addr != end); 1113 return 0; 1114} 1115 1116static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, 1117 unsigned long addr, unsigned long end, 1118 unsigned long pfn, pgprot_t prot) 1119{ 1120 pud_t *pud; 1121 unsigned long next; 1122 1123 pfn -= addr >> PAGE_SHIFT; 1124 pud = pud_alloc(mm, pgd, addr); 1125 if (!pud) 1126 return -ENOMEM; 1127 do { 1128 next = pud_addr_end(addr, end); 1129 if (remap_pmd_range(mm, pud, addr, next, 1130 pfn + (addr >> PAGE_SHIFT), prot)) 1131 return -ENOMEM; 1132 } while (pud++, addr = next, addr != end); 1133 return 0; 1134} 1135 1136/* Note: this is only safe if the mm semaphore is held when called. */ 1137int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 1138 unsigned long pfn, unsigned long size, pgprot_t prot) 1139{ 1140 pgd_t *pgd; 1141 unsigned long next; 1142 unsigned long end = addr + size; 1143 struct mm_struct *mm = vma->vm_mm; 1144 int err; 1145 1146 /* 1147 * Physically remapped pages are special. Tell the 1148 * rest of the world about it: 1149 * VM_IO tells people not to look at these pages 1150 * (accesses can have side effects). 1151 * VM_RESERVED tells swapout not to try to touch 1152 * this region. 1153 */ 1154 vma->vm_flags |= VM_IO | VM_RESERVED; 1155 1156 BUG_ON(addr >= end); 1157 pfn -= addr >> PAGE_SHIFT; 1158 pgd = pgd_offset(mm, addr); 1159 flush_cache_range(vma, addr, end); 1160 spin_lock(&mm->page_table_lock); 1161 do { 1162 next = pgd_addr_end(addr, end); 1163 err = remap_pud_range(mm, pgd, addr, next, 1164 pfn + (addr >> PAGE_SHIFT), prot); 1165 if (err) 1166 break; 1167 } while (pgd++, addr = next, addr != end); 1168 spin_unlock(&mm->page_table_lock); 1169 return err; 1170} 1171EXPORT_SYMBOL(remap_pfn_range); 1172 1173/* 1174 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when 1175 * servicing faults for write access. In the normal case, do always want 1176 * pte_mkwrite. But get_user_pages can cause write faults for mappings 1177 * that do not have writing enabled, when used by access_process_vm. 1178 */ 1179static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) 1180{ 1181 if (likely(vma->vm_flags & VM_WRITE)) 1182 pte = pte_mkwrite(pte); 1183 return pte; 1184} 1185 1186/* 1187 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock 1188 */ 1189static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address, 1190 pte_t *page_table) 1191{ 1192 pte_t entry; 1193 1194 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)), 1195 vma); 1196 ptep_establish(vma, address, page_table, entry); 1197 update_mmu_cache(vma, address, entry); 1198 lazy_mmu_prot_update(entry); 1199} 1200 1201/* 1202 * This routine handles present pages, when users try to write 1203 * to a shared page. It is done by copying the page to a new address 1204 * and decrementing the shared-page counter for the old page. 1205 * 1206 * Goto-purists beware: the only reason for goto's here is that it results 1207 * in better assembly code.. The "default" path will see no jumps at all. 1208 * 1209 * Note that this routine assumes that the protection checks have been 1210 * done by the caller (the low-level page fault routine in most cases). 1211 * Thus we can safely just mark it writable once we've done any necessary 1212 * COW. 1213 * 1214 * We also mark the page dirty at this point even though the page will 1215 * change only once the write actually happens. This avoids a few races, 1216 * and potentially makes it more efficient. 1217 * 1218 * We hold the mm semaphore and the page_table_lock on entry and exit 1219 * with the page_table_lock released. 1220 */ 1221static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma, 1222 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte) 1223{ 1224 struct page *old_page, *new_page; 1225 unsigned long pfn = pte_pfn(pte); 1226 pte_t entry; 1227 1228 if (unlikely(!pfn_valid(pfn))) { 1229 /* 1230 * This should really halt the system so it can be debugged or 1231 * at least the kernel stops what it's doing before it corrupts 1232 * data, but for the moment just pretend this is OOM. 1233 */ 1234 pte_unmap(page_table); 1235 printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n", 1236 address); 1237 spin_unlock(&mm->page_table_lock); 1238 return VM_FAULT_OOM; 1239 } 1240 old_page = pfn_to_page(pfn); 1241 1242 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { 1243 int reuse = can_share_swap_page(old_page); 1244 unlock_page(old_page); 1245 if (reuse) { 1246 flush_cache_page(vma, address, pfn); 1247 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)), 1248 vma); 1249 ptep_set_access_flags(vma, address, page_table, entry, 1); 1250 update_mmu_cache(vma, address, entry); 1251 lazy_mmu_prot_update(entry); 1252 pte_unmap(page_table); 1253 spin_unlock(&mm->page_table_lock); 1254 return VM_FAULT_MINOR; 1255 } 1256 } 1257 pte_unmap(page_table); 1258 1259 /* 1260 * Ok, we need to copy. Oh, well.. 1261 */ 1262 if (!PageReserved(old_page)) 1263 page_cache_get(old_page); 1264 spin_unlock(&mm->page_table_lock); 1265 1266 if (unlikely(anon_vma_prepare(vma))) 1267 goto no_new_page; 1268 if (old_page == ZERO_PAGE(address)) { 1269 new_page = alloc_zeroed_user_highpage(vma, address); 1270 if (!new_page) 1271 goto no_new_page; 1272 } else { 1273 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1274 if (!new_page) 1275 goto no_new_page; 1276 copy_user_highpage(new_page, old_page, address); 1277 } 1278 /* 1279 * Re-check the pte - we dropped the lock 1280 */ 1281 spin_lock(&mm->page_table_lock); 1282 page_table = pte_offset_map(pmd, address); 1283 if (likely(pte_same(*page_table, pte))) { 1284 if (PageAnon(old_page)) 1285 dec_mm_counter(mm, anon_rss); 1286 if (PageReserved(old_page)) 1287 inc_mm_counter(mm, rss); 1288 else 1289 page_remove_rmap(old_page); 1290 flush_cache_page(vma, address, pfn); 1291 break_cow(vma, new_page, address, page_table); 1292 lru_cache_add_active(new_page); 1293 page_add_anon_rmap(new_page, vma, address); 1294 1295 /* Free the old page.. */ 1296 new_page = old_page; 1297 } 1298 pte_unmap(page_table); 1299 page_cache_release(new_page); 1300 page_cache_release(old_page); 1301 spin_unlock(&mm->page_table_lock); 1302 return VM_FAULT_MINOR; 1303 1304no_new_page: 1305 page_cache_release(old_page); 1306 return VM_FAULT_OOM; 1307} 1308 1309/* 1310 * Helper functions for unmap_mapping_range(). 1311 * 1312 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ 1313 * 1314 * We have to restart searching the prio_tree whenever we drop the lock, 1315 * since the iterator is only valid while the lock is held, and anyway 1316 * a later vma might be split and reinserted earlier while lock dropped. 1317 * 1318 * The list of nonlinear vmas could be handled more efficiently, using 1319 * a placeholder, but handle it in the same way until a need is shown. 1320 * It is important to search the prio_tree before nonlinear list: a vma 1321 * may become nonlinear and be shifted from prio_tree to nonlinear list 1322 * while the lock is dropped; but never shifted from list to prio_tree. 1323 * 1324 * In order to make forward progress despite restarting the search, 1325 * vm_truncate_count is used to mark a vma as now dealt with, so we can 1326 * quickly skip it next time around. Since the prio_tree search only 1327 * shows us those vmas affected by unmapping the range in question, we 1328 * can't efficiently keep all vmas in step with mapping->truncate_count: 1329 * so instead reset them all whenever it wraps back to 0 (then go to 1). 1330 * mapping->truncate_count and vma->vm_truncate_count are protected by 1331 * i_mmap_lock. 1332 * 1333 * In order to make forward progress despite repeatedly restarting some 1334 * large vma, note the restart_addr from unmap_vmas when it breaks out: 1335 * and restart from that address when we reach that vma again. It might 1336 * have been split or merged, shrunk or extended, but never shifted: so 1337 * restart_addr remains valid so long as it remains in the vma's range. 1338 * unmap_mapping_range forces truncate_count to leap over page-aligned 1339 * values so we can save vma's restart_addr in its truncate_count field. 1340 */ 1341#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) 1342 1343static void reset_vma_truncate_counts(struct address_space *mapping) 1344{ 1345 struct vm_area_struct *vma; 1346 struct prio_tree_iter iter; 1347 1348 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) 1349 vma->vm_truncate_count = 0; 1350 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) 1351 vma->vm_truncate_count = 0; 1352} 1353 1354static int unmap_mapping_range_vma(struct vm_area_struct *vma, 1355 unsigned long start_addr, unsigned long end_addr, 1356 struct zap_details *details) 1357{ 1358 unsigned long restart_addr; 1359 int need_break; 1360 1361again: 1362 restart_addr = vma->vm_truncate_count; 1363 if (is_restart_addr(restart_addr) && start_addr < restart_addr) { 1364 start_addr = restart_addr; 1365 if (start_addr >= end_addr) { 1366 /* Top of vma has been split off since last time */ 1367 vma->vm_truncate_count = details->truncate_count; 1368 return 0; 1369 } 1370 } 1371 1372 restart_addr = zap_page_range(vma, start_addr, 1373 end_addr - start_addr, details); 1374 1375 /* 1376 * We cannot rely on the break test in unmap_vmas: 1377 * on the one hand, we don't want to restart our loop 1378 * just because that broke out for the page_table_lock; 1379 * on the other hand, it does no test when vma is small. 1380 */ 1381 need_break = need_resched() || 1382 need_lockbreak(details->i_mmap_lock); 1383 1384 if (restart_addr >= end_addr) { 1385 /* We have now completed this vma: mark it so */ 1386 vma->vm_truncate_count = details->truncate_count; 1387 if (!need_break) 1388 return 0; 1389 } else { 1390 /* Note restart_addr in vma's truncate_count field */ 1391 vma->vm_truncate_count = restart_addr; 1392 if (!need_break) 1393 goto again; 1394 } 1395 1396 spin_unlock(details->i_mmap_lock); 1397 cond_resched(); 1398 spin_lock(details->i_mmap_lock); 1399 return -EINTR; 1400} 1401 1402static inline void unmap_mapping_range_tree(struct prio_tree_root *root, 1403 struct zap_details *details) 1404{ 1405 struct vm_area_struct *vma; 1406 struct prio_tree_iter iter; 1407 pgoff_t vba, vea, zba, zea; 1408 1409restart: 1410 vma_prio_tree_foreach(vma, &iter, root, 1411 details->first_index, details->last_index) { 1412 /* Skip quickly over those we have already dealt with */ 1413 if (vma->vm_truncate_count == details->truncate_count) 1414 continue; 1415 1416 vba = vma->vm_pgoff; 1417 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; 1418 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ 1419 zba = details->first_index; 1420 if (zba < vba) 1421 zba = vba; 1422 zea = details->last_index; 1423 if (zea > vea) 1424 zea = vea; 1425 1426 if (unmap_mapping_range_vma(vma, 1427 ((zba - vba) << PAGE_SHIFT) + vma->vm_start, 1428 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, 1429 details) < 0) 1430 goto restart; 1431 } 1432} 1433 1434static inline void unmap_mapping_range_list(struct list_head *head, 1435 struct zap_details *details) 1436{ 1437 struct vm_area_struct *vma; 1438 1439 /* 1440 * In nonlinear VMAs there is no correspondence between virtual address 1441 * offset and file offset. So we must perform an exhaustive search 1442 * across *all* the pages in each nonlinear VMA, not just the pages 1443 * whose virtual address lies outside the file truncation point. 1444 */ 1445restart: 1446 list_for_each_entry(vma, head, shared.vm_set.list) { 1447 /* Skip quickly over those we have already dealt with */ 1448 if (vma->vm_truncate_count == details->truncate_count) 1449 continue; 1450 details->nonlinear_vma = vma; 1451 if (unmap_mapping_range_vma(vma, vma->vm_start, 1452 vma->vm_end, details) < 0) 1453 goto restart; 1454 } 1455} 1456 1457/** 1458 * unmap_mapping_range - unmap the portion of all mmaps 1459 * in the specified address_space corresponding to the specified 1460 * page range in the underlying file. 1461 * @address_space: the address space containing mmaps to be unmapped. 1462 * @holebegin: byte in first page to unmap, relative to the start of 1463 * the underlying file. This will be rounded down to a PAGE_SIZE 1464 * boundary. Note that this is different from vmtruncate(), which 1465 * must keep the partial page. In contrast, we must get rid of 1466 * partial pages. 1467 * @holelen: size of prospective hole in bytes. This will be rounded 1468 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the 1469 * end of the file. 1470 * @even_cows: 1 when truncating a file, unmap even private COWed pages; 1471 * but 0 when invalidating pagecache, don't throw away private data. 1472 */ 1473void unmap_mapping_range(struct address_space *mapping, 1474 loff_t const holebegin, loff_t const holelen, int even_cows) 1475{ 1476 struct zap_details details; 1477 pgoff_t hba = holebegin >> PAGE_SHIFT; 1478 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1479 1480 /* Check for overflow. */ 1481 if (sizeof(holelen) > sizeof(hlen)) { 1482 long long holeend = 1483 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; 1484 if (holeend & ~(long long)ULONG_MAX) 1485 hlen = ULONG_MAX - hba + 1; 1486 } 1487 1488 details.check_mapping = even_cows? NULL: mapping; 1489 details.nonlinear_vma = NULL; 1490 details.first_index = hba; 1491 details.last_index = hba + hlen - 1; 1492 if (details.last_index < details.first_index) 1493 details.last_index = ULONG_MAX; 1494 details.i_mmap_lock = &mapping->i_mmap_lock; 1495 1496 spin_lock(&mapping->i_mmap_lock); 1497 1498 /* serialize i_size write against truncate_count write */ 1499 smp_wmb(); 1500 /* Protect against page faults, and endless unmapping loops */ 1501 mapping->truncate_count++; 1502 /* 1503 * For archs where spin_lock has inclusive semantics like ia64 1504 * this smp_mb() will prevent to read pagetable contents 1505 * before the truncate_count increment is visible to 1506 * other cpus. 1507 */ 1508 smp_mb(); 1509 if (unlikely(is_restart_addr(mapping->truncate_count))) { 1510 if (mapping->truncate_count == 0) 1511 reset_vma_truncate_counts(mapping); 1512 mapping->truncate_count++; 1513 } 1514 details.truncate_count = mapping->truncate_count; 1515 1516 if (unlikely(!prio_tree_empty(&mapping->i_mmap))) 1517 unmap_mapping_range_tree(&mapping->i_mmap, &details); 1518 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) 1519 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); 1520 spin_unlock(&mapping->i_mmap_lock); 1521} 1522EXPORT_SYMBOL(unmap_mapping_range); 1523 1524/* 1525 * Handle all mappings that got truncated by a "truncate()" 1526 * system call. 1527 * 1528 * NOTE! We have to be ready to update the memory sharing 1529 * between the file and the memory map for a potential last 1530 * incomplete page. Ugly, but necessary. 1531 */ 1532int vmtruncate(struct inode * inode, loff_t offset) 1533{ 1534 struct address_space *mapping = inode->i_mapping; 1535 unsigned long limit; 1536 1537 if (inode->i_size < offset) 1538 goto do_expand; 1539 /* 1540 * truncation of in-use swapfiles is disallowed - it would cause 1541 * subsequent swapout to scribble on the now-freed blocks. 1542 */ 1543 if (IS_SWAPFILE(inode)) 1544 goto out_busy; 1545 i_size_write(inode, offset); 1546 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); 1547 truncate_inode_pages(mapping, offset); 1548 goto out_truncate; 1549 1550do_expand: 1551 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; 1552 if (limit != RLIM_INFINITY && offset > limit) 1553 goto out_sig; 1554 if (offset > inode->i_sb->s_maxbytes) 1555 goto out_big; 1556 i_size_write(inode, offset); 1557 1558out_truncate: 1559 if (inode->i_op && inode->i_op->truncate) 1560 inode->i_op->truncate(inode); 1561 return 0; 1562out_sig: 1563 send_sig(SIGXFSZ, current, 0); 1564out_big: 1565 return -EFBIG; 1566out_busy: 1567 return -ETXTBSY; 1568} 1569 1570EXPORT_SYMBOL(vmtruncate); 1571 1572/* 1573 * Primitive swap readahead code. We simply read an aligned block of 1574 * (1 << page_cluster) entries in the swap area. This method is chosen 1575 * because it doesn't cost us any seek time. We also make sure to queue 1576 * the 'original' request together with the readahead ones... 1577 * 1578 * This has been extended to use the NUMA policies from the mm triggering 1579 * the readahead. 1580 * 1581 * Caller must hold down_read on the vma->vm_mm if vma is not NULL. 1582 */ 1583void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) 1584{ 1585#ifdef CONFIG_NUMA 1586 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; 1587#endif 1588 int i, num; 1589 struct page *new_page; 1590 unsigned long offset; 1591 1592 /* 1593 * Get the number of handles we should do readahead io to. 1594 */ 1595 num = valid_swaphandles(entry, &offset); 1596 for (i = 0; i < num; offset++, i++) { 1597 /* Ok, do the async read-ahead now */ 1598 new_page = read_swap_cache_async(swp_entry(swp_type(entry), 1599 offset), vma, addr); 1600 if (!new_page) 1601 break; 1602 page_cache_release(new_page); 1603#ifdef CONFIG_NUMA 1604 /* 1605 * Find the next applicable VMA for the NUMA policy. 1606 */ 1607 addr += PAGE_SIZE; 1608 if (addr == 0) 1609 vma = NULL; 1610 if (vma) { 1611 if (addr >= vma->vm_end) { 1612 vma = next_vma; 1613 next_vma = vma ? vma->vm_next : NULL; 1614 } 1615 if (vma && addr < vma->vm_start) 1616 vma = NULL; 1617 } else { 1618 if (next_vma && addr >= next_vma->vm_start) { 1619 vma = next_vma; 1620 next_vma = vma->vm_next; 1621 } 1622 } 1623#endif 1624 } 1625 lru_add_drain(); /* Push any new pages onto the LRU now */ 1626} 1627 1628/* 1629 * We hold the mm semaphore and the page_table_lock on entry and 1630 * should release the pagetable lock on exit.. 1631 */ 1632static int do_swap_page(struct mm_struct * mm, 1633 struct vm_area_struct * vma, unsigned long address, 1634 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access) 1635{ 1636 struct page *page; 1637 swp_entry_t entry = pte_to_swp_entry(orig_pte); 1638 pte_t pte; 1639 int ret = VM_FAULT_MINOR; 1640 1641 pte_unmap(page_table); 1642 spin_unlock(&mm->page_table_lock); 1643 page = lookup_swap_cache(entry); 1644 if (!page) { 1645 swapin_readahead(entry, address, vma); 1646 page = read_swap_cache_async(entry, vma, address); 1647 if (!page) { 1648 /* 1649 * Back out if somebody else faulted in this pte while 1650 * we released the page table lock. 1651 */ 1652 spin_lock(&mm->page_table_lock); 1653 page_table = pte_offset_map(pmd, address); 1654 if (likely(pte_same(*page_table, orig_pte))) 1655 ret = VM_FAULT_OOM; 1656 else 1657 ret = VM_FAULT_MINOR; 1658 pte_unmap(page_table); 1659 spin_unlock(&mm->page_table_lock); 1660 goto out; 1661 } 1662 1663 /* Had to read the page from swap area: Major fault */ 1664 ret = VM_FAULT_MAJOR; 1665 inc_page_state(pgmajfault); 1666 grab_swap_token(); 1667 } 1668 1669 mark_page_accessed(page); 1670 lock_page(page); 1671 1672 /* 1673 * Back out if somebody else faulted in this pte while we 1674 * released the page table lock. 1675 */ 1676 spin_lock(&mm->page_table_lock); 1677 page_table = pte_offset_map(pmd, address); 1678 if (unlikely(!pte_same(*page_table, orig_pte))) { 1679 ret = VM_FAULT_MINOR; 1680 goto out_nomap; 1681 } 1682 1683 if (unlikely(!PageUptodate(page))) { 1684 ret = VM_FAULT_SIGBUS; 1685 goto out_nomap; 1686 } 1687 1688 /* The page isn't present yet, go ahead with the fault. */ 1689 1690 inc_mm_counter(mm, rss); 1691 pte = mk_pte(page, vma->vm_page_prot); 1692 if (write_access && can_share_swap_page(page)) { 1693 pte = maybe_mkwrite(pte_mkdirty(pte), vma); 1694 write_access = 0; 1695 } 1696 1697 flush_icache_page(vma, page); 1698 set_pte_at(mm, address, page_table, pte); 1699 page_add_anon_rmap(page, vma, address); 1700 1701 swap_free(entry); 1702 if (vm_swap_full()) 1703 remove_exclusive_swap_page(page); 1704 unlock_page(page); 1705 1706 if (write_access) { 1707 if (do_wp_page(mm, vma, address, 1708 page_table, pmd, pte) == VM_FAULT_OOM) 1709 ret = VM_FAULT_OOM; 1710 goto out; 1711 } 1712 1713 /* No need to invalidate - it was non-present before */ 1714 update_mmu_cache(vma, address, pte); 1715 lazy_mmu_prot_update(pte); 1716 pte_unmap(page_table); 1717 spin_unlock(&mm->page_table_lock); 1718out: 1719 return ret; 1720out_nomap: 1721 pte_unmap(page_table); 1722 spin_unlock(&mm->page_table_lock); 1723 unlock_page(page); 1724 page_cache_release(page); 1725 goto out; 1726} 1727 1728/* 1729 * We are called with the MM semaphore and page_table_lock 1730 * spinlock held to protect against concurrent faults in 1731 * multithreaded programs. 1732 */ 1733static int 1734do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, 1735 pte_t *page_table, pmd_t *pmd, int write_access, 1736 unsigned long addr) 1737{ 1738 pte_t entry; 1739 struct page * page = ZERO_PAGE(addr); 1740 1741 /* Read-only mapping of ZERO_PAGE. */ 1742 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot)); 1743 1744 /* ..except if it's a write access */ 1745 if (write_access) { 1746 /* Allocate our own private page. */ 1747 pte_unmap(page_table); 1748 spin_unlock(&mm->page_table_lock); 1749 1750 if (unlikely(anon_vma_prepare(vma))) 1751 goto no_mem; 1752 page = alloc_zeroed_user_highpage(vma, addr); 1753 if (!page) 1754 goto no_mem; 1755 1756 spin_lock(&mm->page_table_lock); 1757 page_table = pte_offset_map(pmd, addr); 1758 1759 if (!pte_none(*page_table)) { 1760 pte_unmap(page_table); 1761 page_cache_release(page); 1762 spin_unlock(&mm->page_table_lock); 1763 goto out; 1764 } 1765 inc_mm_counter(mm, rss); 1766 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page, 1767 vma->vm_page_prot)), 1768 vma); 1769 lru_cache_add_active(page); 1770 SetPageReferenced(page); 1771 page_add_anon_rmap(page, vma, addr); 1772 } 1773 1774 set_pte_at(mm, addr, page_table, entry); 1775 pte_unmap(page_table); 1776 1777 /* No need to invalidate - it was non-present before */ 1778 update_mmu_cache(vma, addr, entry); 1779 lazy_mmu_prot_update(entry); 1780 spin_unlock(&mm->page_table_lock); 1781out: 1782 return VM_FAULT_MINOR; 1783no_mem: 1784 return VM_FAULT_OOM; 1785} 1786 1787/* 1788 * do_no_page() tries to create a new page mapping. It aggressively 1789 * tries to share with existing pages, but makes a separate copy if 1790 * the "write_access" parameter is true in order to avoid the next 1791 * page fault. 1792 * 1793 * As this is called only for pages that do not currently exist, we 1794 * do not need to flush old virtual caches or the TLB. 1795 * 1796 * This is called with the MM semaphore held and the page table 1797 * spinlock held. Exit with the spinlock released. 1798 */ 1799static int 1800do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, 1801 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd) 1802{ 1803 struct page * new_page; 1804 struct address_space *mapping = NULL; 1805 pte_t entry; 1806 unsigned int sequence = 0; 1807 int ret = VM_FAULT_MINOR; 1808 int anon = 0; 1809 1810 if (!vma->vm_ops || !vma->vm_ops->nopage) 1811 return do_anonymous_page(mm, vma, page_table, 1812 pmd, write_access, address); 1813 pte_unmap(page_table); 1814 spin_unlock(&mm->page_table_lock); 1815 1816 if (vma->vm_file) { 1817 mapping = vma->vm_file->f_mapping; 1818 sequence = mapping->truncate_count; 1819 smp_rmb(); /* serializes i_size against truncate_count */ 1820 } 1821retry: 1822 cond_resched(); 1823 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); 1824 /* 1825 * No smp_rmb is needed here as long as there's a full 1826 * spin_lock/unlock sequence inside the ->nopage callback 1827 * (for the pagecache lookup) that acts as an implicit 1828 * smp_mb() and prevents the i_size read to happen 1829 * after the next truncate_count read. 1830 */ 1831 1832 /* no page was available -- either SIGBUS or OOM */ 1833 if (new_page == NOPAGE_SIGBUS) 1834 return VM_FAULT_SIGBUS; 1835 if (new_page == NOPAGE_OOM) 1836 return VM_FAULT_OOM; 1837 1838 /* 1839 * Should we do an early C-O-W break? 1840 */ 1841 if (write_access && !(vma->vm_flags & VM_SHARED)) { 1842 struct page *page; 1843 1844 if (unlikely(anon_vma_prepare(vma))) 1845 goto oom; 1846 page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1847 if (!page) 1848 goto oom; 1849 copy_user_highpage(page, new_page, address); 1850 page_cache_release(new_page); 1851 new_page = page; 1852 anon = 1; 1853 } 1854 1855 spin_lock(&mm->page_table_lock); 1856 /* 1857 * For a file-backed vma, someone could have truncated or otherwise 1858 * invalidated this page. If unmap_mapping_range got called, 1859 * retry getting the page. 1860 */ 1861 if (mapping && unlikely(sequence != mapping->truncate_count)) { 1862 sequence = mapping->truncate_count; 1863 spin_unlock(&mm->page_table_lock); 1864 page_cache_release(new_page); 1865 goto retry; 1866 } 1867 page_table = pte_offset_map(pmd, address); 1868 1869 /* 1870 * This silly early PAGE_DIRTY setting removes a race 1871 * due to the bad i386 page protection. But it's valid 1872 * for other architectures too. 1873 * 1874 * Note that if write_access is true, we either now have 1875 * an exclusive copy of the page, or this is a shared mapping, 1876 * so we can make it writable and dirty to avoid having to 1877 * handle that later. 1878 */ 1879 /* Only go through if we didn't race with anybody else... */ 1880 if (pte_none(*page_table)) { 1881 if (!PageReserved(new_page)) 1882 inc_mm_counter(mm, rss); 1883 1884 flush_icache_page(vma, new_page); 1885 entry = mk_pte(new_page, vma->vm_page_prot); 1886 if (write_access) 1887 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1888 set_pte_at(mm, address, page_table, entry); 1889 if (anon) { 1890 lru_cache_add_active(new_page); 1891 page_add_anon_rmap(new_page, vma, address); 1892 } else 1893 page_add_file_rmap(new_page); 1894 pte_unmap(page_table); 1895 } else { 1896 /* One of our sibling threads was faster, back out. */ 1897 pte_unmap(page_table); 1898 page_cache_release(new_page); 1899 spin_unlock(&mm->page_table_lock); 1900 goto out; 1901 } 1902 1903 /* no need to invalidate: a not-present page shouldn't be cached */ 1904 update_mmu_cache(vma, address, entry); 1905 lazy_mmu_prot_update(entry); 1906 spin_unlock(&mm->page_table_lock); 1907out: 1908 return ret; 1909oom: 1910 page_cache_release(new_page); 1911 ret = VM_FAULT_OOM; 1912 goto out; 1913} 1914 1915/* 1916 * Fault of a previously existing named mapping. Repopulate the pte 1917 * from the encoded file_pte if possible. This enables swappable 1918 * nonlinear vmas. 1919 */ 1920static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma, 1921 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd) 1922{ 1923 unsigned long pgoff; 1924 int err; 1925 1926 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage); 1927 /* 1928 * Fall back to the linear mapping if the fs does not support 1929 * ->populate: 1930 */ 1931 if (!vma->vm_ops || !vma->vm_ops->populate || 1932 (write_access && !(vma->vm_flags & VM_SHARED))) { 1933 pte_clear(mm, address, pte); 1934 return do_no_page(mm, vma, address, write_access, pte, pmd); 1935 } 1936 1937 pgoff = pte_to_pgoff(*pte); 1938 1939 pte_unmap(pte); 1940 spin_unlock(&mm->page_table_lock); 1941 1942 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0); 1943 if (err == -ENOMEM) 1944 return VM_FAULT_OOM; 1945 if (err) 1946 return VM_FAULT_SIGBUS; 1947 return VM_FAULT_MAJOR; 1948} 1949 1950/* 1951 * These routines also need to handle stuff like marking pages dirty 1952 * and/or accessed for architectures that don't do it in hardware (most 1953 * RISC architectures). The early dirtying is also good on the i386. 1954 * 1955 * There is also a hook called "update_mmu_cache()" that architectures 1956 * with external mmu caches can use to update those (ie the Sparc or 1957 * PowerPC hashed page tables that act as extended TLBs). 1958 * 1959 * Note the "page_table_lock". It is to protect against kswapd removing 1960 * pages from under us. Note that kswapd only ever _removes_ pages, never 1961 * adds them. As such, once we have noticed that the page is not present, 1962 * we can drop the lock early. 1963 * 1964 * The adding of pages is protected by the MM semaphore (which we hold), 1965 * so we don't need to worry about a page being suddenly been added into 1966 * our VM. 1967 * 1968 * We enter with the pagetable spinlock held, we are supposed to 1969 * release it when done. 1970 */ 1971static inline int handle_pte_fault(struct mm_struct *mm, 1972 struct vm_area_struct * vma, unsigned long address, 1973 int write_access, pte_t *pte, pmd_t *pmd) 1974{ 1975 pte_t entry; 1976 1977 entry = *pte; 1978 if (!pte_present(entry)) { 1979 /* 1980 * If it truly wasn't present, we know that kswapd 1981 * and the PTE updates will not touch it later. So 1982 * drop the lock. 1983 */ 1984 if (pte_none(entry)) 1985 return do_no_page(mm, vma, address, write_access, pte, pmd); 1986 if (pte_file(entry)) 1987 return do_file_page(mm, vma, address, write_access, pte, pmd); 1988 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access); 1989 } 1990 1991 if (write_access) { 1992 if (!pte_write(entry)) 1993 return do_wp_page(mm, vma, address, pte, pmd, entry); 1994 1995 entry = pte_mkdirty(entry); 1996 } 1997 entry = pte_mkyoung(entry); 1998 ptep_set_access_flags(vma, address, pte, entry, write_access); 1999 update_mmu_cache(vma, address, entry); 2000 lazy_mmu_prot_update(entry); 2001 pte_unmap(pte); 2002 spin_unlock(&mm->page_table_lock); 2003 return VM_FAULT_MINOR; 2004} 2005 2006/* 2007 * By the time we get here, we already hold the mm semaphore 2008 */ 2009int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma, 2010 unsigned long address, int write_access) 2011{ 2012 pgd_t *pgd; 2013 pud_t *pud; 2014 pmd_t *pmd; 2015 pte_t *pte; 2016 2017 __set_current_state(TASK_RUNNING); 2018 2019 inc_page_state(pgfault); 2020 2021 if (is_vm_hugetlb_page(vma)) 2022 return VM_FAULT_SIGBUS; /* mapping truncation does this. */ 2023 2024 /* 2025 * We need the page table lock to synchronize with kswapd 2026 * and the SMP-safe atomic PTE updates. 2027 */ 2028 pgd = pgd_offset(mm, address); 2029 spin_lock(&mm->page_table_lock); 2030 2031 pud = pud_alloc(mm, pgd, address); 2032 if (!pud) 2033 goto oom; 2034 2035 pmd = pmd_alloc(mm, pud, address); 2036 if (!pmd) 2037 goto oom; 2038 2039 pte = pte_alloc_map(mm, pmd, address); 2040 if (!pte) 2041 goto oom; 2042 2043 return handle_pte_fault(mm, vma, address, write_access, pte, pmd); 2044 2045 oom: 2046 spin_unlock(&mm->page_table_lock); 2047 return VM_FAULT_OOM; 2048} 2049 2050#ifndef __PAGETABLE_PUD_FOLDED 2051/* 2052 * Allocate page upper directory. 2053 * 2054 * We've already handled the fast-path in-line, and we own the 2055 * page table lock. 2056 */ 2057pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) 2058{ 2059 pud_t *new; 2060 2061 spin_unlock(&mm->page_table_lock); 2062 new = pud_alloc_one(mm, address); 2063 spin_lock(&mm->page_table_lock); 2064 if (!new) 2065 return NULL; 2066 2067 /* 2068 * Because we dropped the lock, we should re-check the 2069 * entry, as somebody else could have populated it.. 2070 */ 2071 if (pgd_present(*pgd)) { 2072 pud_free(new); 2073 goto out; 2074 } 2075 pgd_populate(mm, pgd, new); 2076 out: 2077 return pud_offset(pgd, address); 2078} 2079#endif /* __PAGETABLE_PUD_FOLDED */ 2080 2081#ifndef __PAGETABLE_PMD_FOLDED 2082/* 2083 * Allocate page middle directory. 2084 * 2085 * We've already handled the fast-path in-line, and we own the 2086 * page table lock. 2087 */ 2088pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) 2089{ 2090 pmd_t *new; 2091 2092 spin_unlock(&mm->page_table_lock); 2093 new = pmd_alloc_one(mm, address); 2094 spin_lock(&mm->page_table_lock); 2095 if (!new) 2096 return NULL; 2097 2098 /* 2099 * Because we dropped the lock, we should re-check the 2100 * entry, as somebody else could have populated it.. 2101 */ 2102#ifndef __ARCH_HAS_4LEVEL_HACK 2103 if (pud_present(*pud)) { 2104 pmd_free(new); 2105 goto out; 2106 } 2107 pud_populate(mm, pud, new); 2108#else 2109 if (pgd_present(*pud)) { 2110 pmd_free(new); 2111 goto out; 2112 } 2113 pgd_populate(mm, pud, new); 2114#endif /* __ARCH_HAS_4LEVEL_HACK */ 2115 2116 out: 2117 return pmd_offset(pud, address); 2118} 2119#endif /* __PAGETABLE_PMD_FOLDED */ 2120 2121int make_pages_present(unsigned long addr, unsigned long end) 2122{ 2123 int ret, len, write; 2124 struct vm_area_struct * vma; 2125 2126 vma = find_vma(current->mm, addr); 2127 if (!vma) 2128 return -1; 2129 write = (vma->vm_flags & VM_WRITE) != 0; 2130 if (addr >= end) 2131 BUG(); 2132 if (end > vma->vm_end) 2133 BUG(); 2134 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; 2135 ret = get_user_pages(current, current->mm, addr, 2136 len, write, 0, NULL, NULL); 2137 if (ret < 0) 2138 return ret; 2139 return ret == len ? 0 : -1; 2140} 2141 2142/* 2143 * Map a vmalloc()-space virtual address to the physical page. 2144 */ 2145struct page * vmalloc_to_page(void * vmalloc_addr) 2146{ 2147 unsigned long addr = (unsigned long) vmalloc_addr; 2148 struct page *page = NULL; 2149 pgd_t *pgd = pgd_offset_k(addr); 2150 pud_t *pud; 2151 pmd_t *pmd; 2152 pte_t *ptep, pte; 2153 2154 if (!pgd_none(*pgd)) { 2155 pud = pud_offset(pgd, addr); 2156 if (!pud_none(*pud)) { 2157 pmd = pmd_offset(pud, addr); 2158 if (!pmd_none(*pmd)) { 2159 ptep = pte_offset_map(pmd, addr); 2160 pte = *ptep; 2161 if (pte_present(pte)) 2162 page = pte_page(pte); 2163 pte_unmap(ptep); 2164 } 2165 } 2166 } 2167 return page; 2168} 2169 2170EXPORT_SYMBOL(vmalloc_to_page); 2171 2172/* 2173 * Map a vmalloc()-space virtual address to the physical page frame number. 2174 */ 2175unsigned long vmalloc_to_pfn(void * vmalloc_addr) 2176{ 2177 return page_to_pfn(vmalloc_to_page(vmalloc_addr)); 2178} 2179 2180EXPORT_SYMBOL(vmalloc_to_pfn); 2181 2182/* 2183 * update_mem_hiwater 2184 * - update per process rss and vm high water data 2185 */ 2186void update_mem_hiwater(struct task_struct *tsk) 2187{ 2188 if (tsk->mm) { 2189 unsigned long rss = get_mm_counter(tsk->mm, rss); 2190 2191 if (tsk->mm->hiwater_rss < rss) 2192 tsk->mm->hiwater_rss = rss; 2193 if (tsk->mm->hiwater_vm < tsk->mm->total_vm) 2194 tsk->mm->hiwater_vm = tsk->mm->total_vm; 2195 } 2196} 2197 2198#if !defined(__HAVE_ARCH_GATE_AREA) 2199 2200#if defined(AT_SYSINFO_EHDR) 2201struct vm_area_struct gate_vma; 2202 2203static int __init gate_vma_init(void) 2204{ 2205 gate_vma.vm_mm = NULL; 2206 gate_vma.vm_start = FIXADDR_USER_START; 2207 gate_vma.vm_end = FIXADDR_USER_END; 2208 gate_vma.vm_page_prot = PAGE_READONLY; 2209 gate_vma.vm_flags = 0; 2210 return 0; 2211} 2212__initcall(gate_vma_init); 2213#endif 2214 2215struct vm_area_struct *get_gate_vma(struct task_struct *tsk) 2216{ 2217#ifdef AT_SYSINFO_EHDR 2218 return &gate_vma; 2219#else 2220 return NULL; 2221#endif 2222} 2223 2224int in_gate_area_no_task(unsigned long addr) 2225{ 2226#ifdef AT_SYSINFO_EHDR 2227 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) 2228 return 1; 2229#endif 2230 return 0; 2231} 2232 2233#endif /* __HAVE_ARCH_GATE_AREA */ 2234