4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
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
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
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.
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
41 #include <linux/kernel_stat.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>
52 #include <asm/pgalloc.h>
53 #include <asm/uaccess.h>
55 #include <asm/tlbflush.h>
56 #include <asm/pgtable.h>
58 #include <linux/swapops.h>
59 #include <linux/elf.h>
61 #ifndef CONFIG_NEED_MULTIPLE_NODES
62 /* use the per-pgdat data instead for discontigmem - mbligh */
63 unsigned long max_mapnr;
66 EXPORT_SYMBOL(max_mapnr);
67 EXPORT_SYMBOL(mem_map);
70 unsigned long num_physpages;
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
79 unsigned long vmalloc_earlyreserve;
81 EXPORT_SYMBOL(num_physpages);
82 EXPORT_SYMBOL(high_memory);
83 EXPORT_SYMBOL(vmalloc_earlyreserve);
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.
91 void pgd_clear_bad(pgd_t *pgd)
97 void pud_clear_bad(pud_t *pud)
103 void pmd_clear_bad(pmd_t *pmd)
110 * Note: this doesn't free the actual pages themselves. That
111 * has been handled earlier when unmapping all the memory regions.
113 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
115 struct page *page = pmd_page(*pmd);
117 pte_free_tlb(tlb, page);
118 dec_page_state(nr_page_table_pages);
122 static 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)
131 pmd = pmd_offset(pud, addr);
133 next = pmd_addr_end(addr, end);
134 if (pmd_none_or_clear_bad(pmd))
136 free_pte_range(tlb, pmd);
137 } while (pmd++, addr = next, addr != end);
147 if (end - 1 > ceiling - 1)
150 pmd = pmd_offset(pud, start);
152 pmd_free_tlb(tlb, pmd);
155 static 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)
164 pud = pud_offset(pgd, addr);
166 next = pud_addr_end(addr, end);
167 if (pud_none_or_clear_bad(pud))
169 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
170 } while (pud++, addr = next, addr != end);
176 ceiling &= PGDIR_MASK;
180 if (end - 1 > ceiling - 1)
183 pud = pud_offset(pgd, start);
185 pud_free_tlb(tlb, pud);
189 * This function frees user-level page tables of a process.
191 * Must be called with pagetable lock held.
193 void free_pgd_range(struct mmu_gather **tlb,
194 unsigned long addr, unsigned long end,
195 unsigned long floor, unsigned long ceiling)
202 * The next few lines have given us lots of grief...
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.
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).
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.
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.
238 if (end - 1 > ceiling - 1)
244 pgd = pgd_offset((*tlb)->mm, addr);
246 next = pgd_addr_end(addr, end);
247 if (pgd_none_or_clear_bad(pgd))
249 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
250 } while (pgd++, addr = next, addr != end);
253 flush_tlb_pgtables((*tlb)->mm, start, end);
256 void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
257 unsigned long floor, unsigned long ceiling)
260 struct vm_area_struct *next = vma->vm_next;
261 unsigned long addr = vma->vm_start;
264 * Hide vma from rmap and vmtruncate before freeing pgtables
266 anon_vma_unlink(vma);
267 unlink_file_vma(vma);
269 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
270 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
271 floor, next? next->vm_start: ceiling);
274 * Optimization: gather nearby vmas into one call down
276 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
277 && !is_hugepage_only_range(vma->vm_mm, next->vm_start,
281 anon_vma_unlink(vma);
282 unlink_file_vma(vma);
284 free_pgd_range(tlb, addr, vma->vm_end,
285 floor, next? next->vm_start: ceiling);
291 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
293 struct page *new = pte_alloc_one(mm, address);
297 spin_lock(&mm->page_table_lock);
298 if (pmd_present(*pmd)) /* Another has populated it */
302 inc_page_state(nr_page_table_pages);
303 pmd_populate(mm, pmd, new);
305 spin_unlock(&mm->page_table_lock);
309 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
311 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
315 spin_lock(&init_mm.page_table_lock);
316 if (pmd_present(*pmd)) /* Another has populated it */
317 pte_free_kernel(new);
319 pmd_populate_kernel(&init_mm, pmd, new);
320 spin_unlock(&init_mm.page_table_lock);
324 static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
327 add_mm_counter(mm, file_rss, file_rss);
329 add_mm_counter(mm, anon_rss, anon_rss);
333 * This function is called to print an error when a pte in a
334 * !VM_RESERVED region is found pointing to an invalid pfn (which
337 * The calling function must still handle the error.
339 void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
341 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
342 "vm_flags = %lx, vaddr = %lx\n",
343 (long long)pte_val(pte),
344 (vma->vm_mm == current->mm ? current->comm : "???"),
345 vma->vm_flags, vaddr);
350 * copy one vm_area from one task to the other. Assumes the page tables
351 * already present in the new task to be cleared in the whole range
352 * covered by this vma.
356 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
357 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
358 unsigned long addr, int *rss)
360 unsigned long vm_flags = vma->vm_flags;
361 pte_t pte = *src_pte;
365 /* pte contains position in swap or file, so copy. */
366 if (unlikely(!pte_present(pte))) {
367 if (!pte_file(pte)) {
368 swap_duplicate(pte_to_swp_entry(pte));
369 /* make sure dst_mm is on swapoff's mmlist. */
370 if (unlikely(list_empty(&dst_mm->mmlist))) {
371 spin_lock(&mmlist_lock);
372 list_add(&dst_mm->mmlist, &src_mm->mmlist);
373 spin_unlock(&mmlist_lock);
379 /* If the region is VM_RESERVED, the mapping is not
380 * mapped via rmap - duplicate the pte as is.
382 if (vm_flags & VM_RESERVED)
386 /* If the pte points outside of valid memory but
387 * the region is not VM_RESERVED, we have a problem.
389 if (unlikely(!pfn_valid(pfn))) {
390 print_bad_pte(vma, pte, addr);
391 goto out_set_pte; /* try to do something sane */
394 page = pfn_to_page(pfn);
397 * If it's a COW mapping, write protect it both
398 * in the parent and the child
400 if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) {
401 ptep_set_wrprotect(src_mm, addr, src_pte);
406 * If it's a shared mapping, mark it clean in
409 if (vm_flags & VM_SHARED)
410 pte = pte_mkclean(pte);
411 pte = pte_mkold(pte);
414 rss[!!PageAnon(page)]++;
417 set_pte_at(dst_mm, addr, dst_pte, pte);
420 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
421 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
422 unsigned long addr, unsigned long end)
424 pte_t *src_pte, *dst_pte;
425 spinlock_t *src_ptl, *dst_ptl;
431 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
434 src_pte = pte_offset_map_nested(src_pmd, addr);
435 src_ptl = &src_mm->page_table_lock;
440 * We are holding two locks at this point - either of them
441 * could generate latencies in another task on another CPU.
443 if (progress >= 32) {
445 if (need_resched() ||
446 need_lockbreak(src_ptl) ||
447 need_lockbreak(dst_ptl))
450 if (pte_none(*src_pte)) {
454 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
456 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
458 spin_unlock(src_ptl);
459 pte_unmap_nested(src_pte - 1);
460 add_mm_rss(dst_mm, rss[0], rss[1]);
461 pte_unmap_unlock(dst_pte - 1, dst_ptl);
468 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
469 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
470 unsigned long addr, unsigned long end)
472 pmd_t *src_pmd, *dst_pmd;
475 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
478 src_pmd = pmd_offset(src_pud, addr);
480 next = pmd_addr_end(addr, end);
481 if (pmd_none_or_clear_bad(src_pmd))
483 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
486 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
490 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
491 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
492 unsigned long addr, unsigned long end)
494 pud_t *src_pud, *dst_pud;
497 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
500 src_pud = pud_offset(src_pgd, addr);
502 next = pud_addr_end(addr, end);
503 if (pud_none_or_clear_bad(src_pud))
505 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
508 } while (dst_pud++, src_pud++, addr = next, addr != end);
512 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
513 struct vm_area_struct *vma)
515 pgd_t *src_pgd, *dst_pgd;
517 unsigned long addr = vma->vm_start;
518 unsigned long end = vma->vm_end;
521 * Don't copy ptes where a page fault will fill them correctly.
522 * Fork becomes much lighter when there are big shared or private
523 * readonly mappings. The tradeoff is that copy_page_range is more
524 * efficient than faulting.
526 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) {
531 if (is_vm_hugetlb_page(vma))
532 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
534 dst_pgd = pgd_offset(dst_mm, addr);
535 src_pgd = pgd_offset(src_mm, addr);
537 next = pgd_addr_end(addr, end);
538 if (pgd_none_or_clear_bad(src_pgd))
540 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
543 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
547 static void zap_pte_range(struct mmu_gather *tlb,
548 struct vm_area_struct *vma, pmd_t *pmd,
549 unsigned long addr, unsigned long end,
550 struct zap_details *details)
552 struct mm_struct *mm = tlb->mm;
558 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
563 if (pte_present(ptent)) {
564 struct page *page = NULL;
565 if (!(vma->vm_flags & VM_RESERVED)) {
566 unsigned long pfn = pte_pfn(ptent);
567 if (unlikely(!pfn_valid(pfn)))
568 print_bad_pte(vma, ptent, addr);
570 page = pfn_to_page(pfn);
572 if (unlikely(details) && page) {
574 * unmap_shared_mapping_pages() wants to
575 * invalidate cache without truncating:
576 * unmap shared but keep private pages.
578 if (details->check_mapping &&
579 details->check_mapping != page->mapping)
582 * Each page->index must be checked when
583 * invalidating or truncating nonlinear.
585 if (details->nonlinear_vma &&
586 (page->index < details->first_index ||
587 page->index > details->last_index))
590 ptent = ptep_get_and_clear_full(mm, addr, pte,
592 tlb_remove_tlb_entry(tlb, pte, addr);
595 if (unlikely(details) && details->nonlinear_vma
596 && linear_page_index(details->nonlinear_vma,
597 addr) != page->index)
598 set_pte_at(mm, addr, pte,
599 pgoff_to_pte(page->index));
603 if (pte_dirty(ptent))
604 set_page_dirty(page);
605 if (pte_young(ptent))
606 mark_page_accessed(page);
609 page_remove_rmap(page);
610 tlb_remove_page(tlb, page);
614 * If details->check_mapping, we leave swap entries;
615 * if details->nonlinear_vma, we leave file entries.
617 if (unlikely(details))
619 if (!pte_file(ptent))
620 free_swap_and_cache(pte_to_swp_entry(ptent));
621 pte_clear_full(mm, addr, pte, tlb->fullmm);
622 } while (pte++, addr += PAGE_SIZE, addr != end);
624 add_mm_rss(mm, file_rss, anon_rss);
625 pte_unmap_unlock(pte - 1, ptl);
628 static inline void zap_pmd_range(struct mmu_gather *tlb,
629 struct vm_area_struct *vma, pud_t *pud,
630 unsigned long addr, unsigned long end,
631 struct zap_details *details)
636 pmd = pmd_offset(pud, addr);
638 next = pmd_addr_end(addr, end);
639 if (pmd_none_or_clear_bad(pmd))
641 zap_pte_range(tlb, vma, pmd, addr, next, details);
642 } while (pmd++, addr = next, addr != end);
645 static inline void zap_pud_range(struct mmu_gather *tlb,
646 struct vm_area_struct *vma, pgd_t *pgd,
647 unsigned long addr, unsigned long end,
648 struct zap_details *details)
653 pud = pud_offset(pgd, addr);
655 next = pud_addr_end(addr, end);
656 if (pud_none_or_clear_bad(pud))
658 zap_pmd_range(tlb, vma, pud, addr, next, details);
659 } while (pud++, addr = next, addr != end);
662 static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
663 unsigned long addr, unsigned long end,
664 struct zap_details *details)
669 if (details && !details->check_mapping && !details->nonlinear_vma)
673 tlb_start_vma(tlb, vma);
674 pgd = pgd_offset(vma->vm_mm, addr);
676 next = pgd_addr_end(addr, end);
677 if (pgd_none_or_clear_bad(pgd))
679 zap_pud_range(tlb, vma, pgd, addr, next, details);
680 } while (pgd++, addr = next, addr != end);
681 tlb_end_vma(tlb, vma);
684 #ifdef CONFIG_PREEMPT
685 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
687 /* No preempt: go for improved straight-line efficiency */
688 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
692 * unmap_vmas - unmap a range of memory covered by a list of vma's
693 * @tlbp: address of the caller's struct mmu_gather
694 * @vma: the starting vma
695 * @start_addr: virtual address at which to start unmapping
696 * @end_addr: virtual address at which to end unmapping
697 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
698 * @details: details of nonlinear truncation or shared cache invalidation
700 * Returns the end address of the unmapping (restart addr if interrupted).
702 * Unmap all pages in the vma list.
704 * We aim to not hold locks for too long (for scheduling latency reasons).
705 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
706 * return the ending mmu_gather to the caller.
708 * Only addresses between `start' and `end' will be unmapped.
710 * The VMA list must be sorted in ascending virtual address order.
712 * unmap_vmas() assumes that the caller will flush the whole unmapped address
713 * range after unmap_vmas() returns. So the only responsibility here is to
714 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
715 * drops the lock and schedules.
717 unsigned long unmap_vmas(struct mmu_gather **tlbp,
718 struct vm_area_struct *vma, unsigned long start_addr,
719 unsigned long end_addr, unsigned long *nr_accounted,
720 struct zap_details *details)
722 unsigned long zap_bytes = ZAP_BLOCK_SIZE;
723 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
724 int tlb_start_valid = 0;
725 unsigned long start = start_addr;
726 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
727 int fullmm = (*tlbp)->fullmm;
729 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
732 start = max(vma->vm_start, start_addr);
733 if (start >= vma->vm_end)
735 end = min(vma->vm_end, end_addr);
736 if (end <= vma->vm_start)
739 if (vma->vm_flags & VM_ACCOUNT)
740 *nr_accounted += (end - start) >> PAGE_SHIFT;
742 while (start != end) {
745 if (!tlb_start_valid) {
750 if (is_vm_hugetlb_page(vma)) {
752 unmap_hugepage_range(vma, start, end);
754 block = min(zap_bytes, end - start);
755 unmap_page_range(*tlbp, vma, start,
756 start + block, details);
761 if ((long)zap_bytes > 0)
764 tlb_finish_mmu(*tlbp, tlb_start, start);
766 if (need_resched() ||
767 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
775 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
777 zap_bytes = ZAP_BLOCK_SIZE;
781 return start; /* which is now the end (or restart) address */
785 * zap_page_range - remove user pages in a given range
786 * @vma: vm_area_struct holding the applicable pages
787 * @address: starting address of pages to zap
788 * @size: number of bytes to zap
789 * @details: details of nonlinear truncation or shared cache invalidation
791 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
792 unsigned long size, struct zap_details *details)
794 struct mm_struct *mm = vma->vm_mm;
795 struct mmu_gather *tlb;
796 unsigned long end = address + size;
797 unsigned long nr_accounted = 0;
800 tlb = tlb_gather_mmu(mm, 0);
801 update_hiwater_rss(mm);
802 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
804 tlb_finish_mmu(tlb, address, end);
809 * Do a quick page-table lookup for a single page.
811 struct page *follow_page(struct mm_struct *mm, unsigned long address,
822 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
824 BUG_ON(flags & FOLL_GET);
829 pgd = pgd_offset(mm, address);
830 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
833 pud = pud_offset(pgd, address);
834 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
837 pmd = pmd_offset(pud, address);
838 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
841 if (pmd_huge(*pmd)) {
842 BUG_ON(flags & FOLL_GET);
843 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
847 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
852 if (!pte_present(pte))
854 if ((flags & FOLL_WRITE) && !pte_write(pte))
860 page = pfn_to_page(pfn);
861 if (flags & FOLL_GET)
863 if (flags & FOLL_TOUCH) {
864 if ((flags & FOLL_WRITE) &&
865 !pte_dirty(pte) && !PageDirty(page))
866 set_page_dirty(page);
867 mark_page_accessed(page);
870 pte_unmap_unlock(ptep, ptl);
876 * When core dumping an enormous anonymous area that nobody
877 * has touched so far, we don't want to allocate page tables.
879 if (flags & FOLL_ANON) {
880 page = ZERO_PAGE(address);
881 if (flags & FOLL_GET)
883 BUG_ON(flags & FOLL_WRITE);
888 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
889 unsigned long start, int len, int write, int force,
890 struct page **pages, struct vm_area_struct **vmas)
893 unsigned int vm_flags;
896 * Require read or write permissions.
897 * If 'force' is set, we only require the "MAY" flags.
899 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
900 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
904 struct vm_area_struct *vma;
905 unsigned int foll_flags;
907 vma = find_extend_vma(mm, start);
908 if (!vma && in_gate_area(tsk, start)) {
909 unsigned long pg = start & PAGE_MASK;
910 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
915 if (write) /* user gate pages are read-only */
916 return i ? : -EFAULT;
918 pgd = pgd_offset_k(pg);
920 pgd = pgd_offset_gate(mm, pg);
921 BUG_ON(pgd_none(*pgd));
922 pud = pud_offset(pgd, pg);
923 BUG_ON(pud_none(*pud));
924 pmd = pmd_offset(pud, pg);
926 return i ? : -EFAULT;
927 pte = pte_offset_map(pmd, pg);
928 if (pte_none(*pte)) {
930 return i ? : -EFAULT;
933 pages[i] = pte_page(*pte);
945 if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
946 || !(vm_flags & vma->vm_flags))
947 return i ? : -EFAULT;
949 if (is_vm_hugetlb_page(vma)) {
950 i = follow_hugetlb_page(mm, vma, pages, vmas,
955 foll_flags = FOLL_TOUCH;
957 foll_flags |= FOLL_GET;
958 if (!write && !(vma->vm_flags & VM_LOCKED) &&
959 (!vma->vm_ops || !vma->vm_ops->nopage))
960 foll_flags |= FOLL_ANON;
966 foll_flags |= FOLL_WRITE;
969 while (!(page = follow_page(mm, start, foll_flags))) {
971 ret = __handle_mm_fault(mm, vma, start,
972 foll_flags & FOLL_WRITE);
974 * The VM_FAULT_WRITE bit tells us that do_wp_page has
975 * broken COW when necessary, even if maybe_mkwrite
976 * decided not to set pte_write. We can thus safely do
977 * subsequent page lookups as if they were reads.
979 if (ret & VM_FAULT_WRITE)
980 foll_flags &= ~FOLL_WRITE;
982 switch (ret & ~VM_FAULT_WRITE) {
989 case VM_FAULT_SIGBUS:
990 return i ? i : -EFAULT;
992 return i ? i : -ENOMEM;
999 flush_dcache_page(page);
1006 } while (len && start < vma->vm_end);
1010 EXPORT_SYMBOL(get_user_pages);
1012 static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1013 unsigned long addr, unsigned long end, pgprot_t prot)
1018 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1022 struct page *page = ZERO_PAGE(addr);
1023 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1024 page_cache_get(page);
1025 page_add_file_rmap(page);
1026 inc_mm_counter(mm, file_rss);
1027 BUG_ON(!pte_none(*pte));
1028 set_pte_at(mm, addr, pte, zero_pte);
1029 } while (pte++, addr += PAGE_SIZE, addr != end);
1030 pte_unmap_unlock(pte - 1, ptl);
1034 static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1035 unsigned long addr, unsigned long end, pgprot_t prot)
1040 pmd = pmd_alloc(mm, pud, addr);
1044 next = pmd_addr_end(addr, end);
1045 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1047 } while (pmd++, addr = next, addr != end);
1051 static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1052 unsigned long addr, unsigned long end, pgprot_t prot)
1057 pud = pud_alloc(mm, pgd, addr);
1061 next = pud_addr_end(addr, end);
1062 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1064 } while (pud++, addr = next, addr != end);
1068 int zeromap_page_range(struct vm_area_struct *vma,
1069 unsigned long addr, unsigned long size, pgprot_t prot)
1073 unsigned long end = addr + size;
1074 struct mm_struct *mm = vma->vm_mm;
1077 BUG_ON(addr >= end);
1078 pgd = pgd_offset(mm, addr);
1079 flush_cache_range(vma, addr, end);
1081 next = pgd_addr_end(addr, end);
1082 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1085 } while (pgd++, addr = next, addr != end);
1090 * maps a range of physical memory into the requested pages. the old
1091 * mappings are removed. any references to nonexistent pages results
1092 * in null mappings (currently treated as "copy-on-access")
1094 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1095 unsigned long addr, unsigned long end,
1096 unsigned long pfn, pgprot_t prot)
1101 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1105 BUG_ON(!pte_none(*pte));
1106 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
1108 } while (pte++, addr += PAGE_SIZE, addr != end);
1109 pte_unmap_unlock(pte - 1, ptl);
1113 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1114 unsigned long addr, unsigned long end,
1115 unsigned long pfn, pgprot_t prot)
1120 pfn -= addr >> PAGE_SHIFT;
1121 pmd = pmd_alloc(mm, pud, addr);
1125 next = pmd_addr_end(addr, end);
1126 if (remap_pte_range(mm, pmd, addr, next,
1127 pfn + (addr >> PAGE_SHIFT), prot))
1129 } while (pmd++, addr = next, addr != end);
1133 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1134 unsigned long addr, unsigned long end,
1135 unsigned long pfn, pgprot_t prot)
1140 pfn -= addr >> PAGE_SHIFT;
1141 pud = pud_alloc(mm, pgd, addr);
1145 next = pud_addr_end(addr, end);
1146 if (remap_pmd_range(mm, pud, addr, next,
1147 pfn + (addr >> PAGE_SHIFT), prot))
1149 } while (pud++, addr = next, addr != end);
1153 /* Note: this is only safe if the mm semaphore is held when called. */
1154 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1155 unsigned long pfn, unsigned long size, pgprot_t prot)
1159 unsigned long end = addr + PAGE_ALIGN(size);
1160 struct mm_struct *mm = vma->vm_mm;
1164 * Physically remapped pages are special. Tell the
1165 * rest of the world about it:
1166 * VM_IO tells people not to look at these pages
1167 * (accesses can have side effects).
1168 * VM_RESERVED tells the core MM not to "manage" these pages
1169 * (e.g. refcount, mapcount, try to swap them out).
1171 vma->vm_flags |= VM_IO | VM_RESERVED;
1173 BUG_ON(addr >= end);
1174 pfn -= addr >> PAGE_SHIFT;
1175 pgd = pgd_offset(mm, addr);
1176 flush_cache_range(vma, addr, end);
1178 next = pgd_addr_end(addr, end);
1179 err = remap_pud_range(mm, pgd, addr, next,
1180 pfn + (addr >> PAGE_SHIFT), prot);
1183 } while (pgd++, addr = next, addr != end);
1186 EXPORT_SYMBOL(remap_pfn_range);
1189 * handle_pte_fault chooses page fault handler according to an entry
1190 * which was read non-atomically. Before making any commitment, on
1191 * those architectures or configurations (e.g. i386 with PAE) which
1192 * might give a mix of unmatched parts, do_swap_page and do_file_page
1193 * must check under lock before unmapping the pte and proceeding
1194 * (but do_wp_page is only called after already making such a check;
1195 * and do_anonymous_page and do_no_page can safely check later on).
1197 static inline int pte_unmap_same(struct mm_struct *mm,
1198 pte_t *page_table, pte_t orig_pte)
1201 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1202 if (sizeof(pte_t) > sizeof(unsigned long)) {
1203 spin_lock(&mm->page_table_lock);
1204 same = pte_same(*page_table, orig_pte);
1205 spin_unlock(&mm->page_table_lock);
1208 pte_unmap(page_table);
1213 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1214 * servicing faults for write access. In the normal case, do always want
1215 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1216 * that do not have writing enabled, when used by access_process_vm.
1218 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1220 if (likely(vma->vm_flags & VM_WRITE))
1221 pte = pte_mkwrite(pte);
1226 * This routine handles present pages, when users try to write
1227 * to a shared page. It is done by copying the page to a new address
1228 * and decrementing the shared-page counter for the old page.
1230 * Note that this routine assumes that the protection checks have been
1231 * done by the caller (the low-level page fault routine in most cases).
1232 * Thus we can safely just mark it writable once we've done any necessary
1235 * We also mark the page dirty at this point even though the page will
1236 * change only once the write actually happens. This avoids a few races,
1237 * and potentially makes it more efficient.
1239 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1240 * but allow concurrent faults), with pte both mapped and locked.
1241 * We return with mmap_sem still held, but pte unmapped and unlocked.
1243 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1244 unsigned long address, pte_t *page_table, pmd_t *pmd,
1245 spinlock_t *ptl, pte_t orig_pte)
1247 struct page *old_page, *new_page;
1248 unsigned long pfn = pte_pfn(orig_pte);
1250 int ret = VM_FAULT_MINOR;
1252 BUG_ON(vma->vm_flags & VM_RESERVED);
1254 if (unlikely(!pfn_valid(pfn))) {
1256 * Page table corrupted: show pte and kill process.
1258 print_bad_pte(vma, orig_pte, address);
1262 old_page = pfn_to_page(pfn);
1264 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
1265 int reuse = can_share_swap_page(old_page);
1266 unlock_page(old_page);
1268 flush_cache_page(vma, address, pfn);
1269 entry = pte_mkyoung(orig_pte);
1270 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1271 ptep_set_access_flags(vma, address, page_table, entry, 1);
1272 update_mmu_cache(vma, address, entry);
1273 lazy_mmu_prot_update(entry);
1274 ret |= VM_FAULT_WRITE;
1280 * Ok, we need to copy. Oh, well..
1282 page_cache_get(old_page);
1283 pte_unmap_unlock(page_table, ptl);
1285 if (unlikely(anon_vma_prepare(vma)))
1287 if (old_page == ZERO_PAGE(address)) {
1288 new_page = alloc_zeroed_user_highpage(vma, address);
1292 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1295 copy_user_highpage(new_page, old_page, address);
1299 * Re-check the pte - we dropped the lock
1301 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1302 if (likely(pte_same(*page_table, orig_pte))) {
1303 page_remove_rmap(old_page);
1304 if (!PageAnon(old_page)) {
1305 inc_mm_counter(mm, anon_rss);
1306 dec_mm_counter(mm, file_rss);
1308 flush_cache_page(vma, address, pfn);
1309 entry = mk_pte(new_page, vma->vm_page_prot);
1310 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1311 ptep_establish(vma, address, page_table, entry);
1312 update_mmu_cache(vma, address, entry);
1313 lazy_mmu_prot_update(entry);
1314 lru_cache_add_active(new_page);
1315 page_add_anon_rmap(new_page, vma, address);
1317 /* Free the old page.. */
1318 new_page = old_page;
1319 ret |= VM_FAULT_WRITE;
1321 page_cache_release(new_page);
1322 page_cache_release(old_page);
1324 pte_unmap_unlock(page_table, ptl);
1327 page_cache_release(old_page);
1328 return VM_FAULT_OOM;
1332 * Helper functions for unmap_mapping_range().
1334 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1336 * We have to restart searching the prio_tree whenever we drop the lock,
1337 * since the iterator is only valid while the lock is held, and anyway
1338 * a later vma might be split and reinserted earlier while lock dropped.
1340 * The list of nonlinear vmas could be handled more efficiently, using
1341 * a placeholder, but handle it in the same way until a need is shown.
1342 * It is important to search the prio_tree before nonlinear list: a vma
1343 * may become nonlinear and be shifted from prio_tree to nonlinear list
1344 * while the lock is dropped; but never shifted from list to prio_tree.
1346 * In order to make forward progress despite restarting the search,
1347 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1348 * quickly skip it next time around. Since the prio_tree search only
1349 * shows us those vmas affected by unmapping the range in question, we
1350 * can't efficiently keep all vmas in step with mapping->truncate_count:
1351 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1352 * mapping->truncate_count and vma->vm_truncate_count are protected by
1355 * In order to make forward progress despite repeatedly restarting some
1356 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1357 * and restart from that address when we reach that vma again. It might
1358 * have been split or merged, shrunk or extended, but never shifted: so
1359 * restart_addr remains valid so long as it remains in the vma's range.
1360 * unmap_mapping_range forces truncate_count to leap over page-aligned
1361 * values so we can save vma's restart_addr in its truncate_count field.
1363 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1365 static void reset_vma_truncate_counts(struct address_space *mapping)
1367 struct vm_area_struct *vma;
1368 struct prio_tree_iter iter;
1370 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1371 vma->vm_truncate_count = 0;
1372 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1373 vma->vm_truncate_count = 0;
1376 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1377 unsigned long start_addr, unsigned long end_addr,
1378 struct zap_details *details)
1380 unsigned long restart_addr;
1384 restart_addr = vma->vm_truncate_count;
1385 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1386 start_addr = restart_addr;
1387 if (start_addr >= end_addr) {
1388 /* Top of vma has been split off since last time */
1389 vma->vm_truncate_count = details->truncate_count;
1394 restart_addr = zap_page_range(vma, start_addr,
1395 end_addr - start_addr, details);
1396 need_break = need_resched() ||
1397 need_lockbreak(details->i_mmap_lock);
1399 if (restart_addr >= end_addr) {
1400 /* We have now completed this vma: mark it so */
1401 vma->vm_truncate_count = details->truncate_count;
1405 /* Note restart_addr in vma's truncate_count field */
1406 vma->vm_truncate_count = restart_addr;
1411 spin_unlock(details->i_mmap_lock);
1413 spin_lock(details->i_mmap_lock);
1417 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1418 struct zap_details *details)
1420 struct vm_area_struct *vma;
1421 struct prio_tree_iter iter;
1422 pgoff_t vba, vea, zba, zea;
1425 vma_prio_tree_foreach(vma, &iter, root,
1426 details->first_index, details->last_index) {
1427 /* Skip quickly over those we have already dealt with */
1428 if (vma->vm_truncate_count == details->truncate_count)
1431 vba = vma->vm_pgoff;
1432 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1433 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1434 zba = details->first_index;
1437 zea = details->last_index;
1441 if (unmap_mapping_range_vma(vma,
1442 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1443 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1449 static inline void unmap_mapping_range_list(struct list_head *head,
1450 struct zap_details *details)
1452 struct vm_area_struct *vma;
1455 * In nonlinear VMAs there is no correspondence between virtual address
1456 * offset and file offset. So we must perform an exhaustive search
1457 * across *all* the pages in each nonlinear VMA, not just the pages
1458 * whose virtual address lies outside the file truncation point.
1461 list_for_each_entry(vma, head, shared.vm_set.list) {
1462 /* Skip quickly over those we have already dealt with */
1463 if (vma->vm_truncate_count == details->truncate_count)
1465 details->nonlinear_vma = vma;
1466 if (unmap_mapping_range_vma(vma, vma->vm_start,
1467 vma->vm_end, details) < 0)
1473 * unmap_mapping_range - unmap the portion of all mmaps
1474 * in the specified address_space corresponding to the specified
1475 * page range in the underlying file.
1476 * @mapping: the address space containing mmaps to be unmapped.
1477 * @holebegin: byte in first page to unmap, relative to the start of
1478 * the underlying file. This will be rounded down to a PAGE_SIZE
1479 * boundary. Note that this is different from vmtruncate(), which
1480 * must keep the partial page. In contrast, we must get rid of
1482 * @holelen: size of prospective hole in bytes. This will be rounded
1483 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1485 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1486 * but 0 when invalidating pagecache, don't throw away private data.
1488 void unmap_mapping_range(struct address_space *mapping,
1489 loff_t const holebegin, loff_t const holelen, int even_cows)
1491 struct zap_details details;
1492 pgoff_t hba = holebegin >> PAGE_SHIFT;
1493 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1495 /* Check for overflow. */
1496 if (sizeof(holelen) > sizeof(hlen)) {
1498 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1499 if (holeend & ~(long long)ULONG_MAX)
1500 hlen = ULONG_MAX - hba + 1;
1503 details.check_mapping = even_cows? NULL: mapping;
1504 details.nonlinear_vma = NULL;
1505 details.first_index = hba;
1506 details.last_index = hba + hlen - 1;
1507 if (details.last_index < details.first_index)
1508 details.last_index = ULONG_MAX;
1509 details.i_mmap_lock = &mapping->i_mmap_lock;
1511 spin_lock(&mapping->i_mmap_lock);
1513 /* serialize i_size write against truncate_count write */
1515 /* Protect against page faults, and endless unmapping loops */
1516 mapping->truncate_count++;
1518 * For archs where spin_lock has inclusive semantics like ia64
1519 * this smp_mb() will prevent to read pagetable contents
1520 * before the truncate_count increment is visible to
1524 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1525 if (mapping->truncate_count == 0)
1526 reset_vma_truncate_counts(mapping);
1527 mapping->truncate_count++;
1529 details.truncate_count = mapping->truncate_count;
1531 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1532 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1533 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1534 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1535 spin_unlock(&mapping->i_mmap_lock);
1537 EXPORT_SYMBOL(unmap_mapping_range);
1540 * Handle all mappings that got truncated by a "truncate()"
1543 * NOTE! We have to be ready to update the memory sharing
1544 * between the file and the memory map for a potential last
1545 * incomplete page. Ugly, but necessary.
1547 int vmtruncate(struct inode * inode, loff_t offset)
1549 struct address_space *mapping = inode->i_mapping;
1550 unsigned long limit;
1552 if (inode->i_size < offset)
1555 * truncation of in-use swapfiles is disallowed - it would cause
1556 * subsequent swapout to scribble on the now-freed blocks.
1558 if (IS_SWAPFILE(inode))
1560 i_size_write(inode, offset);
1561 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1562 truncate_inode_pages(mapping, offset);
1566 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1567 if (limit != RLIM_INFINITY && offset > limit)
1569 if (offset > inode->i_sb->s_maxbytes)
1571 i_size_write(inode, offset);
1574 if (inode->i_op && inode->i_op->truncate)
1575 inode->i_op->truncate(inode);
1578 send_sig(SIGXFSZ, current, 0);
1585 EXPORT_SYMBOL(vmtruncate);
1588 * Primitive swap readahead code. We simply read an aligned block of
1589 * (1 << page_cluster) entries in the swap area. This method is chosen
1590 * because it doesn't cost us any seek time. We also make sure to queue
1591 * the 'original' request together with the readahead ones...
1593 * This has been extended to use the NUMA policies from the mm triggering
1596 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1598 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1601 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1604 struct page *new_page;
1605 unsigned long offset;
1608 * Get the number of handles we should do readahead io to.
1610 num = valid_swaphandles(entry, &offset);
1611 for (i = 0; i < num; offset++, i++) {
1612 /* Ok, do the async read-ahead now */
1613 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1614 offset), vma, addr);
1617 page_cache_release(new_page);
1620 * Find the next applicable VMA for the NUMA policy.
1626 if (addr >= vma->vm_end) {
1628 next_vma = vma ? vma->vm_next : NULL;
1630 if (vma && addr < vma->vm_start)
1633 if (next_vma && addr >= next_vma->vm_start) {
1635 next_vma = vma->vm_next;
1640 lru_add_drain(); /* Push any new pages onto the LRU now */
1644 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1645 * but allow concurrent faults), and pte mapped but not yet locked.
1646 * We return with mmap_sem still held, but pte unmapped and unlocked.
1648 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1649 unsigned long address, pte_t *page_table, pmd_t *pmd,
1650 int write_access, pte_t orig_pte)
1656 int ret = VM_FAULT_MINOR;
1658 if (!pte_unmap_same(mm, page_table, orig_pte))
1661 entry = pte_to_swp_entry(orig_pte);
1662 page = lookup_swap_cache(entry);
1664 swapin_readahead(entry, address, vma);
1665 page = read_swap_cache_async(entry, vma, address);
1668 * Back out if somebody else faulted in this pte
1669 * while we released the pte lock.
1671 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1672 if (likely(pte_same(*page_table, orig_pte)))
1677 /* Had to read the page from swap area: Major fault */
1678 ret = VM_FAULT_MAJOR;
1679 inc_page_state(pgmajfault);
1683 mark_page_accessed(page);
1687 * Back out if somebody else already faulted in this pte.
1689 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1690 if (unlikely(!pte_same(*page_table, orig_pte)))
1693 if (unlikely(!PageUptodate(page))) {
1694 ret = VM_FAULT_SIGBUS;
1698 /* The page isn't present yet, go ahead with the fault. */
1700 inc_mm_counter(mm, anon_rss);
1701 pte = mk_pte(page, vma->vm_page_prot);
1702 if (write_access && can_share_swap_page(page)) {
1703 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1707 flush_icache_page(vma, page);
1708 set_pte_at(mm, address, page_table, pte);
1709 page_add_anon_rmap(page, vma, address);
1713 remove_exclusive_swap_page(page);
1717 if (do_wp_page(mm, vma, address,
1718 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
1723 /* No need to invalidate - it was non-present before */
1724 update_mmu_cache(vma, address, pte);
1725 lazy_mmu_prot_update(pte);
1727 pte_unmap_unlock(page_table, ptl);
1731 pte_unmap_unlock(page_table, ptl);
1733 page_cache_release(page);
1738 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1739 * but allow concurrent faults), and pte mapped but not yet locked.
1740 * We return with mmap_sem still held, but pte unmapped and unlocked.
1742 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1743 unsigned long address, pte_t *page_table, pmd_t *pmd,
1751 /* Allocate our own private page. */
1752 pte_unmap(page_table);
1754 if (unlikely(anon_vma_prepare(vma)))
1756 page = alloc_zeroed_user_highpage(vma, address);
1760 entry = mk_pte(page, vma->vm_page_prot);
1761 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1763 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1764 if (!pte_none(*page_table))
1766 inc_mm_counter(mm, anon_rss);
1767 lru_cache_add_active(page);
1768 SetPageReferenced(page);
1769 page_add_anon_rmap(page, vma, address);
1771 /* Map the ZERO_PAGE - vm_page_prot is readonly */
1772 page = ZERO_PAGE(address);
1773 page_cache_get(page);
1774 entry = mk_pte(page, vma->vm_page_prot);
1776 ptl = &mm->page_table_lock;
1778 if (!pte_none(*page_table))
1780 inc_mm_counter(mm, file_rss);
1781 page_add_file_rmap(page);
1784 set_pte_at(mm, address, page_table, entry);
1786 /* No need to invalidate - it was non-present before */
1787 update_mmu_cache(vma, address, entry);
1788 lazy_mmu_prot_update(entry);
1790 pte_unmap_unlock(page_table, ptl);
1791 return VM_FAULT_MINOR;
1793 page_cache_release(page);
1796 return VM_FAULT_OOM;
1800 * do_no_page() tries to create a new page mapping. It aggressively
1801 * tries to share with existing pages, but makes a separate copy if
1802 * the "write_access" parameter is true in order to avoid the next
1805 * As this is called only for pages that do not currently exist, we
1806 * do not need to flush old virtual caches or the TLB.
1808 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1809 * but allow concurrent faults), and pte mapped but not yet locked.
1810 * We return with mmap_sem still held, but pte unmapped and unlocked.
1812 static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1813 unsigned long address, pte_t *page_table, pmd_t *pmd,
1817 struct page *new_page;
1818 struct address_space *mapping = NULL;
1820 unsigned int sequence = 0;
1821 int ret = VM_FAULT_MINOR;
1824 pte_unmap(page_table);
1827 mapping = vma->vm_file->f_mapping;
1828 sequence = mapping->truncate_count;
1829 smp_rmb(); /* serializes i_size against truncate_count */
1832 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1834 * No smp_rmb is needed here as long as there's a full
1835 * spin_lock/unlock sequence inside the ->nopage callback
1836 * (for the pagecache lookup) that acts as an implicit
1837 * smp_mb() and prevents the i_size read to happen
1838 * after the next truncate_count read.
1841 /* no page was available -- either SIGBUS or OOM */
1842 if (new_page == NOPAGE_SIGBUS)
1843 return VM_FAULT_SIGBUS;
1844 if (new_page == NOPAGE_OOM)
1845 return VM_FAULT_OOM;
1848 * Should we do an early C-O-W break?
1850 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1853 if (unlikely(anon_vma_prepare(vma)))
1855 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1858 copy_user_highpage(page, new_page, address);
1859 page_cache_release(new_page);
1864 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1866 * For a file-backed vma, someone could have truncated or otherwise
1867 * invalidated this page. If unmap_mapping_range got called,
1868 * retry getting the page.
1870 if (mapping && unlikely(sequence != mapping->truncate_count)) {
1871 pte_unmap_unlock(page_table, ptl);
1872 page_cache_release(new_page);
1874 sequence = mapping->truncate_count;
1880 * This silly early PAGE_DIRTY setting removes a race
1881 * due to the bad i386 page protection. But it's valid
1882 * for other architectures too.
1884 * Note that if write_access is true, we either now have
1885 * an exclusive copy of the page, or this is a shared mapping,
1886 * so we can make it writable and dirty to avoid having to
1887 * handle that later.
1889 /* Only go through if we didn't race with anybody else... */
1890 if (pte_none(*page_table)) {
1891 flush_icache_page(vma, new_page);
1892 entry = mk_pte(new_page, vma->vm_page_prot);
1894 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1895 set_pte_at(mm, address, page_table, entry);
1897 inc_mm_counter(mm, anon_rss);
1898 lru_cache_add_active(new_page);
1899 page_add_anon_rmap(new_page, vma, address);
1900 } else if (!(vma->vm_flags & VM_RESERVED)) {
1901 inc_mm_counter(mm, file_rss);
1902 page_add_file_rmap(new_page);
1905 /* One of our sibling threads was faster, back out. */
1906 page_cache_release(new_page);
1910 /* no need to invalidate: a not-present page shouldn't be cached */
1911 update_mmu_cache(vma, address, entry);
1912 lazy_mmu_prot_update(entry);
1914 pte_unmap_unlock(page_table, ptl);
1917 page_cache_release(new_page);
1918 return VM_FAULT_OOM;
1922 * Fault of a previously existing named mapping. Repopulate the pte
1923 * from the encoded file_pte if possible. This enables swappable
1926 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1927 * but allow concurrent faults), and pte mapped but not yet locked.
1928 * We return with mmap_sem still held, but pte unmapped and unlocked.
1930 static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
1931 unsigned long address, pte_t *page_table, pmd_t *pmd,
1932 int write_access, pte_t orig_pte)
1937 if (!pte_unmap_same(mm, page_table, orig_pte))
1938 return VM_FAULT_MINOR;
1940 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
1942 * Page table corrupted: show pte and kill process.
1944 print_bad_pte(vma, orig_pte, address);
1945 return VM_FAULT_OOM;
1947 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
1949 pgoff = pte_to_pgoff(orig_pte);
1950 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
1951 vma->vm_page_prot, pgoff, 0);
1953 return VM_FAULT_OOM;
1955 return VM_FAULT_SIGBUS;
1956 return VM_FAULT_MAJOR;
1960 * These routines also need to handle stuff like marking pages dirty
1961 * and/or accessed for architectures that don't do it in hardware (most
1962 * RISC architectures). The early dirtying is also good on the i386.
1964 * There is also a hook called "update_mmu_cache()" that architectures
1965 * with external mmu caches can use to update those (ie the Sparc or
1966 * PowerPC hashed page tables that act as extended TLBs).
1968 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1969 * but allow concurrent faults), and pte mapped but not yet locked.
1970 * We return with mmap_sem still held, but pte unmapped and unlocked.
1972 static inline int handle_pte_fault(struct mm_struct *mm,
1973 struct vm_area_struct *vma, unsigned long address,
1974 pte_t *pte, pmd_t *pmd, int write_access)
1980 if (!pte_present(entry)) {
1981 if (pte_none(entry)) {
1982 if (!vma->vm_ops || !vma->vm_ops->nopage)
1983 return do_anonymous_page(mm, vma, address,
1984 pte, pmd, write_access);
1985 return do_no_page(mm, vma, address,
1986 pte, pmd, write_access);
1988 if (pte_file(entry))
1989 return do_file_page(mm, vma, address,
1990 pte, pmd, write_access, entry);
1991 return do_swap_page(mm, vma, address,
1992 pte, pmd, write_access, entry);
1995 ptl = &mm->page_table_lock;
1997 if (unlikely(!pte_same(*pte, entry)))
2000 if (!pte_write(entry))
2001 return do_wp_page(mm, vma, address,
2002 pte, pmd, ptl, entry);
2003 entry = pte_mkdirty(entry);
2005 entry = pte_mkyoung(entry);
2006 ptep_set_access_flags(vma, address, pte, entry, write_access);
2007 update_mmu_cache(vma, address, entry);
2008 lazy_mmu_prot_update(entry);
2010 pte_unmap_unlock(pte, ptl);
2011 return VM_FAULT_MINOR;
2015 * By the time we get here, we already hold the mm semaphore
2017 int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2018 unsigned long address, int write_access)
2025 __set_current_state(TASK_RUNNING);
2027 inc_page_state(pgfault);
2029 if (unlikely(is_vm_hugetlb_page(vma)))
2030 return hugetlb_fault(mm, vma, address, write_access);
2032 pgd = pgd_offset(mm, address);
2033 pud = pud_alloc(mm, pgd, address);
2035 return VM_FAULT_OOM;
2036 pmd = pmd_alloc(mm, pud, address);
2038 return VM_FAULT_OOM;
2039 pte = pte_alloc_map(mm, pmd, address);
2041 return VM_FAULT_OOM;
2043 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
2046 #ifndef __PAGETABLE_PUD_FOLDED
2048 * Allocate page upper directory.
2049 * We've already handled the fast-path in-line.
2051 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2053 pud_t *new = pud_alloc_one(mm, address);
2057 spin_lock(&mm->page_table_lock);
2058 if (pgd_present(*pgd)) /* Another has populated it */
2061 pgd_populate(mm, pgd, new);
2062 spin_unlock(&mm->page_table_lock);
2065 #endif /* __PAGETABLE_PUD_FOLDED */
2067 #ifndef __PAGETABLE_PMD_FOLDED
2069 * Allocate page middle directory.
2070 * We've already handled the fast-path in-line.
2072 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2074 pmd_t *new = pmd_alloc_one(mm, address);
2078 spin_lock(&mm->page_table_lock);
2079 #ifndef __ARCH_HAS_4LEVEL_HACK
2080 if (pud_present(*pud)) /* Another has populated it */
2083 pud_populate(mm, pud, new);
2085 if (pgd_present(*pud)) /* Another has populated it */
2088 pgd_populate(mm, pud, new);
2089 #endif /* __ARCH_HAS_4LEVEL_HACK */
2090 spin_unlock(&mm->page_table_lock);
2093 #endif /* __PAGETABLE_PMD_FOLDED */
2095 int make_pages_present(unsigned long addr, unsigned long end)
2097 int ret, len, write;
2098 struct vm_area_struct * vma;
2100 vma = find_vma(current->mm, addr);
2103 write = (vma->vm_flags & VM_WRITE) != 0;
2106 if (end > vma->vm_end)
2108 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2109 ret = get_user_pages(current, current->mm, addr,
2110 len, write, 0, NULL, NULL);
2113 return ret == len ? 0 : -1;
2117 * Map a vmalloc()-space virtual address to the physical page.
2119 struct page * vmalloc_to_page(void * vmalloc_addr)
2121 unsigned long addr = (unsigned long) vmalloc_addr;
2122 struct page *page = NULL;
2123 pgd_t *pgd = pgd_offset_k(addr);
2128 if (!pgd_none(*pgd)) {
2129 pud = pud_offset(pgd, addr);
2130 if (!pud_none(*pud)) {
2131 pmd = pmd_offset(pud, addr);
2132 if (!pmd_none(*pmd)) {
2133 ptep = pte_offset_map(pmd, addr);
2135 if (pte_present(pte))
2136 page = pte_page(pte);
2144 EXPORT_SYMBOL(vmalloc_to_page);
2147 * Map a vmalloc()-space virtual address to the physical page frame number.
2149 unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2151 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2154 EXPORT_SYMBOL(vmalloc_to_pfn);
2156 #if !defined(__HAVE_ARCH_GATE_AREA)
2158 #if defined(AT_SYSINFO_EHDR)
2159 static struct vm_area_struct gate_vma;
2161 static int __init gate_vma_init(void)
2163 gate_vma.vm_mm = NULL;
2164 gate_vma.vm_start = FIXADDR_USER_START;
2165 gate_vma.vm_end = FIXADDR_USER_END;
2166 gate_vma.vm_page_prot = PAGE_READONLY;
2167 gate_vma.vm_flags = VM_RESERVED;
2170 __initcall(gate_vma_init);
2173 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2175 #ifdef AT_SYSINFO_EHDR
2182 int in_gate_area_no_task(unsigned long addr)
2184 #ifdef AT_SYSINFO_EHDR
2185 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2191 #endif /* __HAVE_ARCH_GATE_AREA */