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/delayacct.h>
51 #include <linux/init.h>
52 #include <linux/writeback.h>
54 #include <asm/pgalloc.h>
55 #include <asm/uaccess.h>
57 #include <asm/tlbflush.h>
58 #include <asm/pgtable.h>
60 #include <linux/swapops.h>
61 #include <linux/elf.h>
63 #ifndef CONFIG_NEED_MULTIPLE_NODES
64 /* use the per-pgdat data instead for discontigmem - mbligh */
65 unsigned long max_mapnr;
68 EXPORT_SYMBOL(max_mapnr);
69 EXPORT_SYMBOL(mem_map);
72 unsigned long num_physpages;
74 * A number of key systems in x86 including ioremap() rely on the assumption
75 * that high_memory defines the upper bound on direct map memory, then end
76 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
77 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
81 unsigned long vmalloc_earlyreserve;
83 EXPORT_SYMBOL(num_physpages);
84 EXPORT_SYMBOL(high_memory);
85 EXPORT_SYMBOL(vmalloc_earlyreserve);
87 int randomize_va_space __read_mostly = 1;
89 static int __init disable_randmaps(char *s)
91 randomize_va_space = 0;
94 __setup("norandmaps", disable_randmaps);
98 * If a p?d_bad entry is found while walking page tables, report
99 * the error, before resetting entry to p?d_none. Usually (but
100 * very seldom) called out from the p?d_none_or_clear_bad macros.
103 void pgd_clear_bad(pgd_t *pgd)
109 void pud_clear_bad(pud_t *pud)
115 void pmd_clear_bad(pmd_t *pmd)
122 * Note: this doesn't free the actual pages themselves. That
123 * has been handled earlier when unmapping all the memory regions.
125 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
127 struct page *page = pmd_page(*pmd);
129 pte_lock_deinit(page);
130 pte_free_tlb(tlb, page);
131 dec_zone_page_state(page, NR_PAGETABLE);
135 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
136 unsigned long addr, unsigned long end,
137 unsigned long floor, unsigned long ceiling)
144 pmd = pmd_offset(pud, addr);
146 next = pmd_addr_end(addr, end);
147 if (pmd_none_or_clear_bad(pmd))
149 free_pte_range(tlb, pmd);
150 } while (pmd++, addr = next, addr != end);
160 if (end - 1 > ceiling - 1)
163 pmd = pmd_offset(pud, start);
165 pmd_free_tlb(tlb, pmd);
168 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
169 unsigned long addr, unsigned long end,
170 unsigned long floor, unsigned long ceiling)
177 pud = pud_offset(pgd, addr);
179 next = pud_addr_end(addr, end);
180 if (pud_none_or_clear_bad(pud))
182 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
183 } while (pud++, addr = next, addr != end);
189 ceiling &= PGDIR_MASK;
193 if (end - 1 > ceiling - 1)
196 pud = pud_offset(pgd, start);
198 pud_free_tlb(tlb, pud);
202 * This function frees user-level page tables of a process.
204 * Must be called with pagetable lock held.
206 void free_pgd_range(struct mmu_gather **tlb,
207 unsigned long addr, unsigned long end,
208 unsigned long floor, unsigned long ceiling)
215 * The next few lines have given us lots of grief...
217 * Why are we testing PMD* at this top level? Because often
218 * there will be no work to do at all, and we'd prefer not to
219 * go all the way down to the bottom just to discover that.
221 * Why all these "- 1"s? Because 0 represents both the bottom
222 * of the address space and the top of it (using -1 for the
223 * top wouldn't help much: the masks would do the wrong thing).
224 * The rule is that addr 0 and floor 0 refer to the bottom of
225 * the address space, but end 0 and ceiling 0 refer to the top
226 * Comparisons need to use "end - 1" and "ceiling - 1" (though
227 * that end 0 case should be mythical).
229 * Wherever addr is brought up or ceiling brought down, we must
230 * be careful to reject "the opposite 0" before it confuses the
231 * subsequent tests. But what about where end is brought down
232 * by PMD_SIZE below? no, end can't go down to 0 there.
234 * Whereas we round start (addr) and ceiling down, by different
235 * masks at different levels, in order to test whether a table
236 * now has no other vmas using it, so can be freed, we don't
237 * bother to round floor or end up - the tests don't need that.
251 if (end - 1 > ceiling - 1)
257 pgd = pgd_offset((*tlb)->mm, addr);
259 next = pgd_addr_end(addr, end);
260 if (pgd_none_or_clear_bad(pgd))
262 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
263 } while (pgd++, addr = next, addr != end);
266 flush_tlb_pgtables((*tlb)->mm, start, end);
269 void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
270 unsigned long floor, unsigned long ceiling)
273 struct vm_area_struct *next = vma->vm_next;
274 unsigned long addr = vma->vm_start;
277 * Hide vma from rmap and vmtruncate before freeing pgtables
279 anon_vma_unlink(vma);
280 unlink_file_vma(vma);
282 if (is_vm_hugetlb_page(vma)) {
283 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
284 floor, next? next->vm_start: ceiling);
287 * Optimization: gather nearby vmas into one call down
289 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
290 && !is_vm_hugetlb_page(next)) {
293 anon_vma_unlink(vma);
294 unlink_file_vma(vma);
296 free_pgd_range(tlb, addr, vma->vm_end,
297 floor, next? next->vm_start: ceiling);
303 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
305 struct page *new = pte_alloc_one(mm, address);
310 spin_lock(&mm->page_table_lock);
311 if (pmd_present(*pmd)) { /* Another has populated it */
312 pte_lock_deinit(new);
316 inc_zone_page_state(new, NR_PAGETABLE);
317 pmd_populate(mm, pmd, new);
319 spin_unlock(&mm->page_table_lock);
323 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
325 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
329 spin_lock(&init_mm.page_table_lock);
330 if (pmd_present(*pmd)) /* Another has populated it */
331 pte_free_kernel(new);
333 pmd_populate_kernel(&init_mm, pmd, new);
334 spin_unlock(&init_mm.page_table_lock);
338 static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
341 add_mm_counter(mm, file_rss, file_rss);
343 add_mm_counter(mm, anon_rss, anon_rss);
347 * This function is called to print an error when a bad pte
348 * is found. For example, we might have a PFN-mapped pte in
349 * a region that doesn't allow it.
351 * The calling function must still handle the error.
353 void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
355 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
356 "vm_flags = %lx, vaddr = %lx\n",
357 (long long)pte_val(pte),
358 (vma->vm_mm == current->mm ? current->comm : "???"),
359 vma->vm_flags, vaddr);
363 static inline int is_cow_mapping(unsigned int flags)
365 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
369 * This function gets the "struct page" associated with a pte.
371 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
372 * will have each page table entry just pointing to a raw page frame
373 * number, and as far as the VM layer is concerned, those do not have
374 * pages associated with them - even if the PFN might point to memory
375 * that otherwise is perfectly fine and has a "struct page".
377 * The way we recognize those mappings is through the rules set up
378 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
379 * and the vm_pgoff will point to the first PFN mapped: thus every
380 * page that is a raw mapping will always honor the rule
382 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
384 * and if that isn't true, the page has been COW'ed (in which case it
385 * _does_ have a "struct page" associated with it even if it is in a
388 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
390 unsigned long pfn = pte_pfn(pte);
392 if (unlikely(vma->vm_flags & VM_PFNMAP)) {
393 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
394 if (pfn == vma->vm_pgoff + off)
396 if (!is_cow_mapping(vma->vm_flags))
401 * Add some anal sanity checks for now. Eventually,
402 * we should just do "return pfn_to_page(pfn)", but
403 * in the meantime we check that we get a valid pfn,
404 * and that the resulting page looks ok.
406 if (unlikely(!pfn_valid(pfn))) {
407 print_bad_pte(vma, pte, addr);
412 * NOTE! We still have PageReserved() pages in the page
415 * The PAGE_ZERO() pages and various VDSO mappings can
416 * cause them to exist.
418 return pfn_to_page(pfn);
422 * copy one vm_area from one task to the other. Assumes the page tables
423 * already present in the new task to be cleared in the whole range
424 * covered by this vma.
428 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
429 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
430 unsigned long addr, int *rss)
432 unsigned long vm_flags = vma->vm_flags;
433 pte_t pte = *src_pte;
436 /* pte contains position in swap or file, so copy. */
437 if (unlikely(!pte_present(pte))) {
438 if (!pte_file(pte)) {
439 swp_entry_t entry = pte_to_swp_entry(pte);
441 swap_duplicate(entry);
442 /* make sure dst_mm is on swapoff's mmlist. */
443 if (unlikely(list_empty(&dst_mm->mmlist))) {
444 spin_lock(&mmlist_lock);
445 if (list_empty(&dst_mm->mmlist))
446 list_add(&dst_mm->mmlist,
448 spin_unlock(&mmlist_lock);
450 if (is_write_migration_entry(entry) &&
451 is_cow_mapping(vm_flags)) {
453 * COW mappings require pages in both parent
454 * and child to be set to read.
456 make_migration_entry_read(&entry);
457 pte = swp_entry_to_pte(entry);
458 set_pte_at(src_mm, addr, src_pte, pte);
465 * If it's a COW mapping, write protect it both
466 * in the parent and the child
468 if (is_cow_mapping(vm_flags)) {
469 ptep_set_wrprotect(src_mm, addr, src_pte);
470 pte = pte_wrprotect(pte);
474 * If it's a shared mapping, mark it clean in
477 if (vm_flags & VM_SHARED)
478 pte = pte_mkclean(pte);
479 pte = pte_mkold(pte);
481 page = vm_normal_page(vma, addr, pte);
484 page_dup_rmap(page, vma, addr);
485 rss[!!PageAnon(page)]++;
489 set_pte_at(dst_mm, addr, dst_pte, pte);
492 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
493 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
494 unsigned long addr, unsigned long end)
496 pte_t *src_pte, *dst_pte;
497 spinlock_t *src_ptl, *dst_ptl;
503 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
506 src_pte = pte_offset_map_nested(src_pmd, addr);
507 src_ptl = pte_lockptr(src_mm, src_pmd);
508 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
509 arch_enter_lazy_mmu_mode();
513 * We are holding two locks at this point - either of them
514 * could generate latencies in another task on another CPU.
516 if (progress >= 32) {
518 if (need_resched() ||
519 need_lockbreak(src_ptl) ||
520 need_lockbreak(dst_ptl))
523 if (pte_none(*src_pte)) {
527 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
529 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
531 arch_leave_lazy_mmu_mode();
532 spin_unlock(src_ptl);
533 pte_unmap_nested(src_pte - 1);
534 add_mm_rss(dst_mm, rss[0], rss[1]);
535 pte_unmap_unlock(dst_pte - 1, dst_ptl);
542 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
543 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
544 unsigned long addr, unsigned long end)
546 pmd_t *src_pmd, *dst_pmd;
549 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
552 src_pmd = pmd_offset(src_pud, addr);
554 next = pmd_addr_end(addr, end);
555 if (pmd_none_or_clear_bad(src_pmd))
557 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
560 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
564 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
565 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
566 unsigned long addr, unsigned long end)
568 pud_t *src_pud, *dst_pud;
571 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
574 src_pud = pud_offset(src_pgd, addr);
576 next = pud_addr_end(addr, end);
577 if (pud_none_or_clear_bad(src_pud))
579 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
582 } while (dst_pud++, src_pud++, addr = next, addr != end);
586 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
587 struct vm_area_struct *vma)
589 pgd_t *src_pgd, *dst_pgd;
591 unsigned long addr = vma->vm_start;
592 unsigned long end = vma->vm_end;
595 * Don't copy ptes where a page fault will fill them correctly.
596 * Fork becomes much lighter when there are big shared or private
597 * readonly mappings. The tradeoff is that copy_page_range is more
598 * efficient than faulting.
600 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
605 if (is_vm_hugetlb_page(vma))
606 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
608 dst_pgd = pgd_offset(dst_mm, addr);
609 src_pgd = pgd_offset(src_mm, addr);
611 next = pgd_addr_end(addr, end);
612 if (pgd_none_or_clear_bad(src_pgd))
614 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
617 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
621 static unsigned long zap_pte_range(struct mmu_gather *tlb,
622 struct vm_area_struct *vma, pmd_t *pmd,
623 unsigned long addr, unsigned long end,
624 long *zap_work, struct zap_details *details)
626 struct mm_struct *mm = tlb->mm;
632 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
633 arch_enter_lazy_mmu_mode();
636 if (pte_none(ptent)) {
641 (*zap_work) -= PAGE_SIZE;
643 if (pte_present(ptent)) {
646 page = vm_normal_page(vma, addr, ptent);
647 if (unlikely(details) && page) {
649 * unmap_shared_mapping_pages() wants to
650 * invalidate cache without truncating:
651 * unmap shared but keep private pages.
653 if (details->check_mapping &&
654 details->check_mapping != page->mapping)
657 * Each page->index must be checked when
658 * invalidating or truncating nonlinear.
660 if (details->nonlinear_vma &&
661 (page->index < details->first_index ||
662 page->index > details->last_index))
665 ptent = ptep_get_and_clear_full(mm, addr, pte,
667 tlb_remove_tlb_entry(tlb, pte, addr);
670 if (unlikely(details) && details->nonlinear_vma
671 && linear_page_index(details->nonlinear_vma,
672 addr) != page->index)
673 set_pte_at(mm, addr, pte,
674 pgoff_to_pte(page->index));
678 if (pte_dirty(ptent))
679 set_page_dirty(page);
680 if (pte_young(ptent))
681 SetPageReferenced(page);
684 page_remove_rmap(page, vma);
685 tlb_remove_page(tlb, page);
689 * If details->check_mapping, we leave swap entries;
690 * if details->nonlinear_vma, we leave file entries.
692 if (unlikely(details))
694 if (!pte_file(ptent))
695 free_swap_and_cache(pte_to_swp_entry(ptent));
696 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
697 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
699 add_mm_rss(mm, file_rss, anon_rss);
700 arch_leave_lazy_mmu_mode();
701 pte_unmap_unlock(pte - 1, ptl);
706 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
707 struct vm_area_struct *vma, pud_t *pud,
708 unsigned long addr, unsigned long end,
709 long *zap_work, struct zap_details *details)
714 pmd = pmd_offset(pud, addr);
716 next = pmd_addr_end(addr, end);
717 if (pmd_none_or_clear_bad(pmd)) {
721 next = zap_pte_range(tlb, vma, pmd, addr, next,
723 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
728 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
729 struct vm_area_struct *vma, pgd_t *pgd,
730 unsigned long addr, unsigned long end,
731 long *zap_work, struct zap_details *details)
736 pud = pud_offset(pgd, addr);
738 next = pud_addr_end(addr, end);
739 if (pud_none_or_clear_bad(pud)) {
743 next = zap_pmd_range(tlb, vma, pud, addr, next,
745 } while (pud++, addr = next, (addr != end && *zap_work > 0));
750 static unsigned long unmap_page_range(struct mmu_gather *tlb,
751 struct vm_area_struct *vma,
752 unsigned long addr, unsigned long end,
753 long *zap_work, struct zap_details *details)
758 if (details && !details->check_mapping && !details->nonlinear_vma)
762 tlb_start_vma(tlb, vma);
763 pgd = pgd_offset(vma->vm_mm, addr);
765 next = pgd_addr_end(addr, end);
766 if (pgd_none_or_clear_bad(pgd)) {
770 next = zap_pud_range(tlb, vma, pgd, addr, next,
772 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
773 tlb_end_vma(tlb, vma);
778 #ifdef CONFIG_PREEMPT
779 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
781 /* No preempt: go for improved straight-line efficiency */
782 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
786 * unmap_vmas - unmap a range of memory covered by a list of vma's
787 * @tlbp: address of the caller's struct mmu_gather
788 * @vma: the starting vma
789 * @start_addr: virtual address at which to start unmapping
790 * @end_addr: virtual address at which to end unmapping
791 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
792 * @details: details of nonlinear truncation or shared cache invalidation
794 * Returns the end address of the unmapping (restart addr if interrupted).
796 * Unmap all pages in the vma list.
798 * We aim to not hold locks for too long (for scheduling latency reasons).
799 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
800 * return the ending mmu_gather to the caller.
802 * Only addresses between `start' and `end' will be unmapped.
804 * The VMA list must be sorted in ascending virtual address order.
806 * unmap_vmas() assumes that the caller will flush the whole unmapped address
807 * range after unmap_vmas() returns. So the only responsibility here is to
808 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
809 * drops the lock and schedules.
811 unsigned long unmap_vmas(struct mmu_gather **tlbp,
812 struct vm_area_struct *vma, unsigned long start_addr,
813 unsigned long end_addr, unsigned long *nr_accounted,
814 struct zap_details *details)
816 long zap_work = ZAP_BLOCK_SIZE;
817 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
818 int tlb_start_valid = 0;
819 unsigned long start = start_addr;
820 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
821 int fullmm = (*tlbp)->fullmm;
823 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
826 start = max(vma->vm_start, start_addr);
827 if (start >= vma->vm_end)
829 end = min(vma->vm_end, end_addr);
830 if (end <= vma->vm_start)
833 if (vma->vm_flags & VM_ACCOUNT)
834 *nr_accounted += (end - start) >> PAGE_SHIFT;
836 while (start != end) {
837 if (!tlb_start_valid) {
842 if (unlikely(is_vm_hugetlb_page(vma))) {
843 unmap_hugepage_range(vma, start, end);
844 zap_work -= (end - start) /
845 (HPAGE_SIZE / PAGE_SIZE);
848 start = unmap_page_range(*tlbp, vma,
849 start, end, &zap_work, details);
852 BUG_ON(start != end);
856 tlb_finish_mmu(*tlbp, tlb_start, start);
858 if (need_resched() ||
859 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
867 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
869 zap_work = ZAP_BLOCK_SIZE;
873 return start; /* which is now the end (or restart) address */
877 * zap_page_range - remove user pages in a given range
878 * @vma: vm_area_struct holding the applicable pages
879 * @address: starting address of pages to zap
880 * @size: number of bytes to zap
881 * @details: details of nonlinear truncation or shared cache invalidation
883 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
884 unsigned long size, struct zap_details *details)
886 struct mm_struct *mm = vma->vm_mm;
887 struct mmu_gather *tlb;
888 unsigned long end = address + size;
889 unsigned long nr_accounted = 0;
892 tlb = tlb_gather_mmu(mm, 0);
893 update_hiwater_rss(mm);
894 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
896 tlb_finish_mmu(tlb, address, end);
901 * Do a quick page-table lookup for a single page.
903 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
912 struct mm_struct *mm = vma->vm_mm;
914 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
916 BUG_ON(flags & FOLL_GET);
921 pgd = pgd_offset(mm, address);
922 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
925 pud = pud_offset(pgd, address);
926 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
929 pmd = pmd_offset(pud, address);
930 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
933 if (pmd_huge(*pmd)) {
934 BUG_ON(flags & FOLL_GET);
935 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
939 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
944 if (!pte_present(pte))
946 if ((flags & FOLL_WRITE) && !pte_write(pte))
948 page = vm_normal_page(vma, address, pte);
952 if (flags & FOLL_GET)
954 if (flags & FOLL_TOUCH) {
955 if ((flags & FOLL_WRITE) &&
956 !pte_dirty(pte) && !PageDirty(page))
957 set_page_dirty(page);
958 mark_page_accessed(page);
961 pte_unmap_unlock(ptep, ptl);
967 * When core dumping an enormous anonymous area that nobody
968 * has touched so far, we don't want to allocate page tables.
970 if (flags & FOLL_ANON) {
971 page = ZERO_PAGE(address);
972 if (flags & FOLL_GET)
974 BUG_ON(flags & FOLL_WRITE);
979 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
980 unsigned long start, int len, int write, int force,
981 struct page **pages, struct vm_area_struct **vmas)
984 unsigned int vm_flags;
989 * Require read or write permissions.
990 * If 'force' is set, we only require the "MAY" flags.
992 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
993 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
997 struct vm_area_struct *vma;
998 unsigned int foll_flags;
1000 vma = find_extend_vma(mm, start);
1001 if (!vma && in_gate_area(tsk, start)) {
1002 unsigned long pg = start & PAGE_MASK;
1003 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1008 if (write) /* user gate pages are read-only */
1009 return i ? : -EFAULT;
1011 pgd = pgd_offset_k(pg);
1013 pgd = pgd_offset_gate(mm, pg);
1014 BUG_ON(pgd_none(*pgd));
1015 pud = pud_offset(pgd, pg);
1016 BUG_ON(pud_none(*pud));
1017 pmd = pmd_offset(pud, pg);
1019 return i ? : -EFAULT;
1020 pte = pte_offset_map(pmd, pg);
1021 if (pte_none(*pte)) {
1023 return i ? : -EFAULT;
1026 struct page *page = vm_normal_page(gate_vma, start, *pte);
1040 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
1041 || !(vm_flags & vma->vm_flags))
1042 return i ? : -EFAULT;
1044 if (is_vm_hugetlb_page(vma)) {
1045 i = follow_hugetlb_page(mm, vma, pages, vmas,
1050 foll_flags = FOLL_TOUCH;
1052 foll_flags |= FOLL_GET;
1053 if (!write && !(vma->vm_flags & VM_LOCKED) &&
1054 (!vma->vm_ops || !vma->vm_ops->nopage))
1055 foll_flags |= FOLL_ANON;
1061 foll_flags |= FOLL_WRITE;
1064 while (!(page = follow_page(vma, start, foll_flags))) {
1066 ret = __handle_mm_fault(mm, vma, start,
1067 foll_flags & FOLL_WRITE);
1069 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1070 * broken COW when necessary, even if maybe_mkwrite
1071 * decided not to set pte_write. We can thus safely do
1072 * subsequent page lookups as if they were reads.
1074 if (ret & VM_FAULT_WRITE)
1075 foll_flags &= ~FOLL_WRITE;
1077 switch (ret & ~VM_FAULT_WRITE) {
1078 case VM_FAULT_MINOR:
1081 case VM_FAULT_MAJOR:
1084 case VM_FAULT_SIGBUS:
1085 return i ? i : -EFAULT;
1087 return i ? i : -ENOMEM;
1096 flush_anon_page(vma, page, start);
1097 flush_dcache_page(page);
1104 } while (len && start < vma->vm_end);
1108 EXPORT_SYMBOL(get_user_pages);
1110 static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1111 unsigned long addr, unsigned long end, pgprot_t prot)
1117 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1120 arch_enter_lazy_mmu_mode();
1122 struct page *page = ZERO_PAGE(addr);
1123 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1125 if (unlikely(!pte_none(*pte))) {
1130 page_cache_get(page);
1131 page_add_file_rmap(page);
1132 inc_mm_counter(mm, file_rss);
1133 set_pte_at(mm, addr, pte, zero_pte);
1134 } while (pte++, addr += PAGE_SIZE, addr != end);
1135 arch_leave_lazy_mmu_mode();
1136 pte_unmap_unlock(pte - 1, ptl);
1140 static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1141 unsigned long addr, unsigned long end, pgprot_t prot)
1147 pmd = pmd_alloc(mm, pud, addr);
1151 next = pmd_addr_end(addr, end);
1152 err = zeromap_pte_range(mm, pmd, addr, next, prot);
1155 } while (pmd++, addr = next, addr != end);
1159 static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1160 unsigned long addr, unsigned long end, pgprot_t prot)
1166 pud = pud_alloc(mm, pgd, addr);
1170 next = pud_addr_end(addr, end);
1171 err = zeromap_pmd_range(mm, pud, addr, next, prot);
1174 } while (pud++, addr = next, addr != end);
1178 int zeromap_page_range(struct vm_area_struct *vma,
1179 unsigned long addr, unsigned long size, pgprot_t prot)
1183 unsigned long end = addr + size;
1184 struct mm_struct *mm = vma->vm_mm;
1187 BUG_ON(addr >= end);
1188 pgd = pgd_offset(mm, addr);
1189 flush_cache_range(vma, addr, end);
1191 next = pgd_addr_end(addr, end);
1192 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1195 } while (pgd++, addr = next, addr != end);
1199 pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
1201 pgd_t * pgd = pgd_offset(mm, addr);
1202 pud_t * pud = pud_alloc(mm, pgd, addr);
1204 pmd_t * pmd = pmd_alloc(mm, pud, addr);
1206 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1212 * This is the old fallback for page remapping.
1214 * For historical reasons, it only allows reserved pages. Only
1215 * old drivers should use this, and they needed to mark their
1216 * pages reserved for the old functions anyway.
1218 static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
1228 flush_dcache_page(page);
1229 pte = get_locked_pte(mm, addr, &ptl);
1233 if (!pte_none(*pte))
1236 /* Ok, finally just insert the thing.. */
1238 inc_mm_counter(mm, file_rss);
1239 page_add_file_rmap(page);
1240 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1244 pte_unmap_unlock(pte, ptl);
1250 * vm_insert_page - insert single page into user vma
1251 * @vma: user vma to map to
1252 * @addr: target user address of this page
1253 * @page: source kernel page
1255 * This allows drivers to insert individual pages they've allocated
1258 * The page has to be a nice clean _individual_ kernel allocation.
1259 * If you allocate a compound page, you need to have marked it as
1260 * such (__GFP_COMP), or manually just split the page up yourself
1261 * (see split_page()).
1263 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1264 * took an arbitrary page protection parameter. This doesn't allow
1265 * that. Your vma protection will have to be set up correctly, which
1266 * means that if you want a shared writable mapping, you'd better
1267 * ask for a shared writable mapping!
1269 * The page does not need to be reserved.
1271 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1273 if (addr < vma->vm_start || addr >= vma->vm_end)
1275 if (!page_count(page))
1277 vma->vm_flags |= VM_INSERTPAGE;
1278 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1280 EXPORT_SYMBOL(vm_insert_page);
1283 * vm_insert_pfn - insert single pfn into user vma
1284 * @vma: user vma to map to
1285 * @addr: target user address of this page
1286 * @pfn: source kernel pfn
1288 * Similar to vm_inert_page, this allows drivers to insert individual pages
1289 * they've allocated into a user vma. Same comments apply.
1291 * This function should only be called from a vm_ops->fault handler, and
1292 * in that case the handler should return NULL.
1294 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1297 struct mm_struct *mm = vma->vm_mm;
1302 BUG_ON(!(vma->vm_flags & VM_PFNMAP));
1303 BUG_ON(is_cow_mapping(vma->vm_flags));
1306 pte = get_locked_pte(mm, addr, &ptl);
1310 if (!pte_none(*pte))
1313 /* Ok, finally just insert the thing.. */
1314 entry = pfn_pte(pfn, vma->vm_page_prot);
1315 set_pte_at(mm, addr, pte, entry);
1316 update_mmu_cache(vma, addr, entry);
1320 pte_unmap_unlock(pte, ptl);
1325 EXPORT_SYMBOL(vm_insert_pfn);
1328 * maps a range of physical memory into the requested pages. the old
1329 * mappings are removed. any references to nonexistent pages results
1330 * in null mappings (currently treated as "copy-on-access")
1332 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1333 unsigned long addr, unsigned long end,
1334 unsigned long pfn, pgprot_t prot)
1339 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1342 arch_enter_lazy_mmu_mode();
1344 BUG_ON(!pte_none(*pte));
1345 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
1347 } while (pte++, addr += PAGE_SIZE, addr != end);
1348 arch_leave_lazy_mmu_mode();
1349 pte_unmap_unlock(pte - 1, ptl);
1353 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1354 unsigned long addr, unsigned long end,
1355 unsigned long pfn, pgprot_t prot)
1360 pfn -= addr >> PAGE_SHIFT;
1361 pmd = pmd_alloc(mm, pud, addr);
1365 next = pmd_addr_end(addr, end);
1366 if (remap_pte_range(mm, pmd, addr, next,
1367 pfn + (addr >> PAGE_SHIFT), prot))
1369 } while (pmd++, addr = next, addr != end);
1373 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1374 unsigned long addr, unsigned long end,
1375 unsigned long pfn, pgprot_t prot)
1380 pfn -= addr >> PAGE_SHIFT;
1381 pud = pud_alloc(mm, pgd, addr);
1385 next = pud_addr_end(addr, end);
1386 if (remap_pmd_range(mm, pud, addr, next,
1387 pfn + (addr >> PAGE_SHIFT), prot))
1389 } while (pud++, addr = next, addr != end);
1394 * remap_pfn_range - remap kernel memory to userspace
1395 * @vma: user vma to map to
1396 * @addr: target user address to start at
1397 * @pfn: physical address of kernel memory
1398 * @size: size of map area
1399 * @prot: page protection flags for this mapping
1401 * Note: this is only safe if the mm semaphore is held when called.
1403 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1404 unsigned long pfn, unsigned long size, pgprot_t prot)
1408 unsigned long end = addr + PAGE_ALIGN(size);
1409 struct mm_struct *mm = vma->vm_mm;
1413 * Physically remapped pages are special. Tell the
1414 * rest of the world about it:
1415 * VM_IO tells people not to look at these pages
1416 * (accesses can have side effects).
1417 * VM_RESERVED is specified all over the place, because
1418 * in 2.4 it kept swapout's vma scan off this vma; but
1419 * in 2.6 the LRU scan won't even find its pages, so this
1420 * flag means no more than count its pages in reserved_vm,
1421 * and omit it from core dump, even when VM_IO turned off.
1422 * VM_PFNMAP tells the core MM that the base pages are just
1423 * raw PFN mappings, and do not have a "struct page" associated
1426 * There's a horrible special case to handle copy-on-write
1427 * behaviour that some programs depend on. We mark the "original"
1428 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1430 if (is_cow_mapping(vma->vm_flags)) {
1431 if (addr != vma->vm_start || end != vma->vm_end)
1433 vma->vm_pgoff = pfn;
1436 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
1438 BUG_ON(addr >= end);
1439 pfn -= addr >> PAGE_SHIFT;
1440 pgd = pgd_offset(mm, addr);
1441 flush_cache_range(vma, addr, end);
1443 next = pgd_addr_end(addr, end);
1444 err = remap_pud_range(mm, pgd, addr, next,
1445 pfn + (addr >> PAGE_SHIFT), prot);
1448 } while (pgd++, addr = next, addr != end);
1451 EXPORT_SYMBOL(remap_pfn_range);
1453 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1454 unsigned long addr, unsigned long end,
1455 pte_fn_t fn, void *data)
1459 struct page *pmd_page;
1460 spinlock_t *uninitialized_var(ptl);
1462 pte = (mm == &init_mm) ?
1463 pte_alloc_kernel(pmd, addr) :
1464 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1468 BUG_ON(pmd_huge(*pmd));
1470 pmd_page = pmd_page(*pmd);
1473 err = fn(pte, pmd_page, addr, data);
1476 } while (pte++, addr += PAGE_SIZE, addr != end);
1479 pte_unmap_unlock(pte-1, ptl);
1483 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1484 unsigned long addr, unsigned long end,
1485 pte_fn_t fn, void *data)
1491 pmd = pmd_alloc(mm, pud, addr);
1495 next = pmd_addr_end(addr, end);
1496 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1499 } while (pmd++, addr = next, addr != end);
1503 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1504 unsigned long addr, unsigned long end,
1505 pte_fn_t fn, void *data)
1511 pud = pud_alloc(mm, pgd, addr);
1515 next = pud_addr_end(addr, end);
1516 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1519 } while (pud++, addr = next, addr != end);
1524 * Scan a region of virtual memory, filling in page tables as necessary
1525 * and calling a provided function on each leaf page table.
1527 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1528 unsigned long size, pte_fn_t fn, void *data)
1532 unsigned long end = addr + size;
1535 BUG_ON(addr >= end);
1536 pgd = pgd_offset(mm, addr);
1538 next = pgd_addr_end(addr, end);
1539 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
1542 } while (pgd++, addr = next, addr != end);
1545 EXPORT_SYMBOL_GPL(apply_to_page_range);
1548 * handle_pte_fault chooses page fault handler according to an entry
1549 * which was read non-atomically. Before making any commitment, on
1550 * those architectures or configurations (e.g. i386 with PAE) which
1551 * might give a mix of unmatched parts, do_swap_page and do_file_page
1552 * must check under lock before unmapping the pte and proceeding
1553 * (but do_wp_page is only called after already making such a check;
1554 * and do_anonymous_page and do_no_page can safely check later on).
1556 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
1557 pte_t *page_table, pte_t orig_pte)
1560 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1561 if (sizeof(pte_t) > sizeof(unsigned long)) {
1562 spinlock_t *ptl = pte_lockptr(mm, pmd);
1564 same = pte_same(*page_table, orig_pte);
1568 pte_unmap(page_table);
1573 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1574 * servicing faults for write access. In the normal case, do always want
1575 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1576 * that do not have writing enabled, when used by access_process_vm.
1578 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1580 if (likely(vma->vm_flags & VM_WRITE))
1581 pte = pte_mkwrite(pte);
1585 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
1588 * If the source page was a PFN mapping, we don't have
1589 * a "struct page" for it. We do a best-effort copy by
1590 * just copying from the original user address. If that
1591 * fails, we just zero-fill it. Live with it.
1593 if (unlikely(!src)) {
1594 void *kaddr = kmap_atomic(dst, KM_USER0);
1595 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1598 * This really shouldn't fail, because the page is there
1599 * in the page tables. But it might just be unreadable,
1600 * in which case we just give up and fill the result with
1603 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
1604 memset(kaddr, 0, PAGE_SIZE);
1605 kunmap_atomic(kaddr, KM_USER0);
1606 flush_dcache_page(dst);
1610 copy_user_highpage(dst, src, va, vma);
1614 * This routine handles present pages, when users try to write
1615 * to a shared page. It is done by copying the page to a new address
1616 * and decrementing the shared-page counter for the old page.
1618 * Note that this routine assumes that the protection checks have been
1619 * done by the caller (the low-level page fault routine in most cases).
1620 * Thus we can safely just mark it writable once we've done any necessary
1623 * We also mark the page dirty at this point even though the page will
1624 * change only once the write actually happens. This avoids a few races,
1625 * and potentially makes it more efficient.
1627 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1628 * but allow concurrent faults), with pte both mapped and locked.
1629 * We return with mmap_sem still held, but pte unmapped and unlocked.
1631 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1632 unsigned long address, pte_t *page_table, pmd_t *pmd,
1633 spinlock_t *ptl, pte_t orig_pte)
1635 struct page *old_page, *new_page;
1637 int reuse = 0, ret = VM_FAULT_MINOR;
1638 struct page *dirty_page = NULL;
1640 old_page = vm_normal_page(vma, address, orig_pte);
1645 * Take out anonymous pages first, anonymous shared vmas are
1646 * not dirty accountable.
1648 if (PageAnon(old_page)) {
1649 if (!TestSetPageLocked(old_page)) {
1650 reuse = can_share_swap_page(old_page);
1651 unlock_page(old_page);
1653 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
1654 (VM_WRITE|VM_SHARED))) {
1656 * Only catch write-faults on shared writable pages,
1657 * read-only shared pages can get COWed by
1658 * get_user_pages(.write=1, .force=1).
1660 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
1662 * Notify the address space that the page is about to
1663 * become writable so that it can prohibit this or wait
1664 * for the page to get into an appropriate state.
1666 * We do this without the lock held, so that it can
1667 * sleep if it needs to.
1669 page_cache_get(old_page);
1670 pte_unmap_unlock(page_table, ptl);
1672 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
1673 goto unwritable_page;
1676 * Since we dropped the lock we need to revalidate
1677 * the PTE as someone else may have changed it. If
1678 * they did, we just return, as we can count on the
1679 * MMU to tell us if they didn't also make it writable.
1681 page_table = pte_offset_map_lock(mm, pmd, address,
1683 page_cache_release(old_page);
1684 if (!pte_same(*page_table, orig_pte))
1687 dirty_page = old_page;
1688 get_page(dirty_page);
1693 flush_cache_page(vma, address, pte_pfn(orig_pte));
1694 entry = pte_mkyoung(orig_pte);
1695 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1696 if (ptep_set_access_flags(vma, address, page_table, entry,1)) {
1697 update_mmu_cache(vma, address, entry);
1698 lazy_mmu_prot_update(entry);
1700 ret |= VM_FAULT_WRITE;
1705 * Ok, we need to copy. Oh, well..
1707 page_cache_get(old_page);
1709 pte_unmap_unlock(page_table, ptl);
1711 if (unlikely(anon_vma_prepare(vma)))
1713 if (old_page == ZERO_PAGE(address)) {
1714 new_page = alloc_zeroed_user_highpage(vma, address);
1718 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1721 cow_user_page(new_page, old_page, address, vma);
1725 * Re-check the pte - we dropped the lock
1727 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1728 if (likely(pte_same(*page_table, orig_pte))) {
1730 page_remove_rmap(old_page, vma);
1731 if (!PageAnon(old_page)) {
1732 dec_mm_counter(mm, file_rss);
1733 inc_mm_counter(mm, anon_rss);
1736 inc_mm_counter(mm, anon_rss);
1737 flush_cache_page(vma, address, pte_pfn(orig_pte));
1738 entry = mk_pte(new_page, vma->vm_page_prot);
1739 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1740 lazy_mmu_prot_update(entry);
1742 * Clear the pte entry and flush it first, before updating the
1743 * pte with the new entry. This will avoid a race condition
1744 * seen in the presence of one thread doing SMC and another
1747 ptep_clear_flush(vma, address, page_table);
1748 set_pte_at(mm, address, page_table, entry);
1749 update_mmu_cache(vma, address, entry);
1750 lru_cache_add_active(new_page);
1751 page_add_new_anon_rmap(new_page, vma, address);
1753 /* Free the old page.. */
1754 new_page = old_page;
1755 ret |= VM_FAULT_WRITE;
1758 page_cache_release(new_page);
1760 page_cache_release(old_page);
1762 pte_unmap_unlock(page_table, ptl);
1764 set_page_dirty_balance(dirty_page);
1765 put_page(dirty_page);
1770 page_cache_release(old_page);
1771 return VM_FAULT_OOM;
1774 page_cache_release(old_page);
1775 return VM_FAULT_SIGBUS;
1779 * Helper functions for unmap_mapping_range().
1781 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1783 * We have to restart searching the prio_tree whenever we drop the lock,
1784 * since the iterator is only valid while the lock is held, and anyway
1785 * a later vma might be split and reinserted earlier while lock dropped.
1787 * The list of nonlinear vmas could be handled more efficiently, using
1788 * a placeholder, but handle it in the same way until a need is shown.
1789 * It is important to search the prio_tree before nonlinear list: a vma
1790 * may become nonlinear and be shifted from prio_tree to nonlinear list
1791 * while the lock is dropped; but never shifted from list to prio_tree.
1793 * In order to make forward progress despite restarting the search,
1794 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1795 * quickly skip it next time around. Since the prio_tree search only
1796 * shows us those vmas affected by unmapping the range in question, we
1797 * can't efficiently keep all vmas in step with mapping->truncate_count:
1798 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1799 * mapping->truncate_count and vma->vm_truncate_count are protected by
1802 * In order to make forward progress despite repeatedly restarting some
1803 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1804 * and restart from that address when we reach that vma again. It might
1805 * have been split or merged, shrunk or extended, but never shifted: so
1806 * restart_addr remains valid so long as it remains in the vma's range.
1807 * unmap_mapping_range forces truncate_count to leap over page-aligned
1808 * values so we can save vma's restart_addr in its truncate_count field.
1810 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1812 static void reset_vma_truncate_counts(struct address_space *mapping)
1814 struct vm_area_struct *vma;
1815 struct prio_tree_iter iter;
1817 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1818 vma->vm_truncate_count = 0;
1819 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1820 vma->vm_truncate_count = 0;
1823 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1824 unsigned long start_addr, unsigned long end_addr,
1825 struct zap_details *details)
1827 unsigned long restart_addr;
1831 restart_addr = vma->vm_truncate_count;
1832 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1833 start_addr = restart_addr;
1834 if (start_addr >= end_addr) {
1835 /* Top of vma has been split off since last time */
1836 vma->vm_truncate_count = details->truncate_count;
1841 restart_addr = zap_page_range(vma, start_addr,
1842 end_addr - start_addr, details);
1843 need_break = need_resched() ||
1844 need_lockbreak(details->i_mmap_lock);
1846 if (restart_addr >= end_addr) {
1847 /* We have now completed this vma: mark it so */
1848 vma->vm_truncate_count = details->truncate_count;
1852 /* Note restart_addr in vma's truncate_count field */
1853 vma->vm_truncate_count = restart_addr;
1858 spin_unlock(details->i_mmap_lock);
1860 spin_lock(details->i_mmap_lock);
1864 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1865 struct zap_details *details)
1867 struct vm_area_struct *vma;
1868 struct prio_tree_iter iter;
1869 pgoff_t vba, vea, zba, zea;
1872 vma_prio_tree_foreach(vma, &iter, root,
1873 details->first_index, details->last_index) {
1874 /* Skip quickly over those we have already dealt with */
1875 if (vma->vm_truncate_count == details->truncate_count)
1878 vba = vma->vm_pgoff;
1879 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1880 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1881 zba = details->first_index;
1884 zea = details->last_index;
1888 if (unmap_mapping_range_vma(vma,
1889 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1890 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1896 static inline void unmap_mapping_range_list(struct list_head *head,
1897 struct zap_details *details)
1899 struct vm_area_struct *vma;
1902 * In nonlinear VMAs there is no correspondence between virtual address
1903 * offset and file offset. So we must perform an exhaustive search
1904 * across *all* the pages in each nonlinear VMA, not just the pages
1905 * whose virtual address lies outside the file truncation point.
1908 list_for_each_entry(vma, head, shared.vm_set.list) {
1909 /* Skip quickly over those we have already dealt with */
1910 if (vma->vm_truncate_count == details->truncate_count)
1912 details->nonlinear_vma = vma;
1913 if (unmap_mapping_range_vma(vma, vma->vm_start,
1914 vma->vm_end, details) < 0)
1920 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
1921 * @mapping: the address space containing mmaps to be unmapped.
1922 * @holebegin: byte in first page to unmap, relative to the start of
1923 * the underlying file. This will be rounded down to a PAGE_SIZE
1924 * boundary. Note that this is different from vmtruncate(), which
1925 * must keep the partial page. In contrast, we must get rid of
1927 * @holelen: size of prospective hole in bytes. This will be rounded
1928 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1930 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1931 * but 0 when invalidating pagecache, don't throw away private data.
1933 void unmap_mapping_range(struct address_space *mapping,
1934 loff_t const holebegin, loff_t const holelen, int even_cows)
1936 struct zap_details details;
1937 pgoff_t hba = holebegin >> PAGE_SHIFT;
1938 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1940 /* Check for overflow. */
1941 if (sizeof(holelen) > sizeof(hlen)) {
1943 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1944 if (holeend & ~(long long)ULONG_MAX)
1945 hlen = ULONG_MAX - hba + 1;
1948 details.check_mapping = even_cows? NULL: mapping;
1949 details.nonlinear_vma = NULL;
1950 details.first_index = hba;
1951 details.last_index = hba + hlen - 1;
1952 if (details.last_index < details.first_index)
1953 details.last_index = ULONG_MAX;
1954 details.i_mmap_lock = &mapping->i_mmap_lock;
1956 spin_lock(&mapping->i_mmap_lock);
1958 /* serialize i_size write against truncate_count write */
1960 /* Protect against page faults, and endless unmapping loops */
1961 mapping->truncate_count++;
1963 * For archs where spin_lock has inclusive semantics like ia64
1964 * this smp_mb() will prevent to read pagetable contents
1965 * before the truncate_count increment is visible to
1969 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1970 if (mapping->truncate_count == 0)
1971 reset_vma_truncate_counts(mapping);
1972 mapping->truncate_count++;
1974 details.truncate_count = mapping->truncate_count;
1976 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1977 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1978 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1979 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1980 spin_unlock(&mapping->i_mmap_lock);
1982 EXPORT_SYMBOL(unmap_mapping_range);
1985 * vmtruncate - unmap mappings "freed" by truncate() syscall
1986 * @inode: inode of the file used
1987 * @offset: file offset to start truncating
1989 * NOTE! We have to be ready to update the memory sharing
1990 * between the file and the memory map for a potential last
1991 * incomplete page. Ugly, but necessary.
1993 int vmtruncate(struct inode * inode, loff_t offset)
1995 struct address_space *mapping = inode->i_mapping;
1996 unsigned long limit;
1998 if (inode->i_size < offset)
2001 * truncation of in-use swapfiles is disallowed - it would cause
2002 * subsequent swapout to scribble on the now-freed blocks.
2004 if (IS_SWAPFILE(inode))
2006 i_size_write(inode, offset);
2007 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2008 truncate_inode_pages(mapping, offset);
2012 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
2013 if (limit != RLIM_INFINITY && offset > limit)
2015 if (offset > inode->i_sb->s_maxbytes)
2017 i_size_write(inode, offset);
2020 if (inode->i_op && inode->i_op->truncate)
2021 inode->i_op->truncate(inode);
2024 send_sig(SIGXFSZ, current, 0);
2030 EXPORT_SYMBOL(vmtruncate);
2032 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2034 struct address_space *mapping = inode->i_mapping;
2037 * If the underlying filesystem is not going to provide
2038 * a way to truncate a range of blocks (punch a hole) -
2039 * we should return failure right now.
2041 if (!inode->i_op || !inode->i_op->truncate_range)
2044 mutex_lock(&inode->i_mutex);
2045 down_write(&inode->i_alloc_sem);
2046 unmap_mapping_range(mapping, offset, (end - offset), 1);
2047 truncate_inode_pages_range(mapping, offset, end);
2048 inode->i_op->truncate_range(inode, offset, end);
2049 up_write(&inode->i_alloc_sem);
2050 mutex_unlock(&inode->i_mutex);
2056 * swapin_readahead - swap in pages in hope we need them soon
2057 * @entry: swap entry of this memory
2058 * @addr: address to start
2059 * @vma: user vma this addresses belong to
2061 * Primitive swap readahead code. We simply read an aligned block of
2062 * (1 << page_cluster) entries in the swap area. This method is chosen
2063 * because it doesn't cost us any seek time. We also make sure to queue
2064 * the 'original' request together with the readahead ones...
2066 * This has been extended to use the NUMA policies from the mm triggering
2069 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
2071 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
2074 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
2077 struct page *new_page;
2078 unsigned long offset;
2081 * Get the number of handles we should do readahead io to.
2083 num = valid_swaphandles(entry, &offset);
2084 for (i = 0; i < num; offset++, i++) {
2085 /* Ok, do the async read-ahead now */
2086 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
2087 offset), vma, addr);
2090 page_cache_release(new_page);
2093 * Find the next applicable VMA for the NUMA policy.
2099 if (addr >= vma->vm_end) {
2101 next_vma = vma ? vma->vm_next : NULL;
2103 if (vma && addr < vma->vm_start)
2106 if (next_vma && addr >= next_vma->vm_start) {
2108 next_vma = vma->vm_next;
2113 lru_add_drain(); /* Push any new pages onto the LRU now */
2117 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2118 * but allow concurrent faults), and pte mapped but not yet locked.
2119 * We return with mmap_sem still held, but pte unmapped and unlocked.
2121 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2122 unsigned long address, pte_t *page_table, pmd_t *pmd,
2123 int write_access, pte_t orig_pte)
2129 int ret = VM_FAULT_MINOR;
2131 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2134 entry = pte_to_swp_entry(orig_pte);
2135 if (is_migration_entry(entry)) {
2136 migration_entry_wait(mm, pmd, address);
2139 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2140 page = lookup_swap_cache(entry);
2142 grab_swap_token(); /* Contend for token _before_ read-in */
2143 swapin_readahead(entry, address, vma);
2144 page = read_swap_cache_async(entry, vma, address);
2147 * Back out if somebody else faulted in this pte
2148 * while we released the pte lock.
2150 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2151 if (likely(pte_same(*page_table, orig_pte)))
2153 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2157 /* Had to read the page from swap area: Major fault */
2158 ret = VM_FAULT_MAJOR;
2159 count_vm_event(PGMAJFAULT);
2162 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2163 mark_page_accessed(page);
2167 * Back out if somebody else already faulted in this pte.
2169 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2170 if (unlikely(!pte_same(*page_table, orig_pte)))
2173 if (unlikely(!PageUptodate(page))) {
2174 ret = VM_FAULT_SIGBUS;
2178 /* The page isn't present yet, go ahead with the fault. */
2180 inc_mm_counter(mm, anon_rss);
2181 pte = mk_pte(page, vma->vm_page_prot);
2182 if (write_access && can_share_swap_page(page)) {
2183 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2187 flush_icache_page(vma, page);
2188 set_pte_at(mm, address, page_table, pte);
2189 page_add_anon_rmap(page, vma, address);
2193 remove_exclusive_swap_page(page);
2197 if (do_wp_page(mm, vma, address,
2198 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
2203 /* No need to invalidate - it was non-present before */
2204 update_mmu_cache(vma, address, pte);
2205 lazy_mmu_prot_update(pte);
2207 pte_unmap_unlock(page_table, ptl);
2211 pte_unmap_unlock(page_table, ptl);
2213 page_cache_release(page);
2218 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2219 * but allow concurrent faults), and pte mapped but not yet locked.
2220 * We return with mmap_sem still held, but pte unmapped and unlocked.
2222 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2223 unsigned long address, pte_t *page_table, pmd_t *pmd,
2231 /* Allocate our own private page. */
2232 pte_unmap(page_table);
2234 if (unlikely(anon_vma_prepare(vma)))
2236 page = alloc_zeroed_user_highpage(vma, address);
2240 entry = mk_pte(page, vma->vm_page_prot);
2241 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2243 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2244 if (!pte_none(*page_table))
2246 inc_mm_counter(mm, anon_rss);
2247 lru_cache_add_active(page);
2248 page_add_new_anon_rmap(page, vma, address);
2250 /* Map the ZERO_PAGE - vm_page_prot is readonly */
2251 page = ZERO_PAGE(address);
2252 page_cache_get(page);
2253 entry = mk_pte(page, vma->vm_page_prot);
2255 ptl = pte_lockptr(mm, pmd);
2257 if (!pte_none(*page_table))
2259 inc_mm_counter(mm, file_rss);
2260 page_add_file_rmap(page);
2263 set_pte_at(mm, address, page_table, entry);
2265 /* No need to invalidate - it was non-present before */
2266 update_mmu_cache(vma, address, entry);
2267 lazy_mmu_prot_update(entry);
2269 pte_unmap_unlock(page_table, ptl);
2270 return VM_FAULT_MINOR;
2272 page_cache_release(page);
2275 return VM_FAULT_OOM;
2279 * do_no_page() tries to create a new page mapping. It aggressively
2280 * tries to share with existing pages, but makes a separate copy if
2281 * the "write_access" parameter is true in order to avoid the next
2284 * As this is called only for pages that do not currently exist, we
2285 * do not need to flush old virtual caches or the TLB.
2287 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2288 * but allow concurrent faults), and pte mapped but not yet locked.
2289 * We return with mmap_sem still held, but pte unmapped and unlocked.
2291 static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2292 unsigned long address, pte_t *page_table, pmd_t *pmd,
2296 struct page *new_page;
2297 struct address_space *mapping = NULL;
2299 unsigned int sequence = 0;
2300 int ret = VM_FAULT_MINOR;
2302 struct page *dirty_page = NULL;
2304 pte_unmap(page_table);
2305 BUG_ON(vma->vm_flags & VM_PFNMAP);
2308 mapping = vma->vm_file->f_mapping;
2309 sequence = mapping->truncate_count;
2310 smp_rmb(); /* serializes i_size against truncate_count */
2313 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2315 * No smp_rmb is needed here as long as there's a full
2316 * spin_lock/unlock sequence inside the ->nopage callback
2317 * (for the pagecache lookup) that acts as an implicit
2318 * smp_mb() and prevents the i_size read to happen
2319 * after the next truncate_count read.
2322 /* no page was available -- either SIGBUS, OOM or REFAULT */
2323 if (unlikely(new_page == NOPAGE_SIGBUS))
2324 return VM_FAULT_SIGBUS;
2325 else if (unlikely(new_page == NOPAGE_OOM))
2326 return VM_FAULT_OOM;
2327 else if (unlikely(new_page == NOPAGE_REFAULT))
2328 return VM_FAULT_MINOR;
2331 * Should we do an early C-O-W break?
2334 if (!(vma->vm_flags & VM_SHARED)) {
2337 if (unlikely(anon_vma_prepare(vma)))
2339 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
2342 copy_user_highpage(page, new_page, address, vma);
2343 page_cache_release(new_page);
2348 /* if the page will be shareable, see if the backing
2349 * address space wants to know that the page is about
2350 * to become writable */
2351 if (vma->vm_ops->page_mkwrite &&
2352 vma->vm_ops->page_mkwrite(vma, new_page) < 0
2354 page_cache_release(new_page);
2355 return VM_FAULT_SIGBUS;
2360 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2362 * For a file-backed vma, someone could have truncated or otherwise
2363 * invalidated this page. If unmap_mapping_range got called,
2364 * retry getting the page.
2366 if (mapping && unlikely(sequence != mapping->truncate_count)) {
2367 pte_unmap_unlock(page_table, ptl);
2368 page_cache_release(new_page);
2370 sequence = mapping->truncate_count;
2376 * This silly early PAGE_DIRTY setting removes a race
2377 * due to the bad i386 page protection. But it's valid
2378 * for other architectures too.
2380 * Note that if write_access is true, we either now have
2381 * an exclusive copy of the page, or this is a shared mapping,
2382 * so we can make it writable and dirty to avoid having to
2383 * handle that later.
2385 /* Only go through if we didn't race with anybody else... */
2386 if (pte_none(*page_table)) {
2387 flush_icache_page(vma, new_page);
2388 entry = mk_pte(new_page, vma->vm_page_prot);
2390 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2391 set_pte_at(mm, address, page_table, entry);
2393 inc_mm_counter(mm, anon_rss);
2394 lru_cache_add_active(new_page);
2395 page_add_new_anon_rmap(new_page, vma, address);
2397 inc_mm_counter(mm, file_rss);
2398 page_add_file_rmap(new_page);
2400 dirty_page = new_page;
2401 get_page(dirty_page);
2405 /* One of our sibling threads was faster, back out. */
2406 page_cache_release(new_page);
2410 /* no need to invalidate: a not-present page shouldn't be cached */
2411 update_mmu_cache(vma, address, entry);
2412 lazy_mmu_prot_update(entry);
2414 pte_unmap_unlock(page_table, ptl);
2416 set_page_dirty_balance(dirty_page);
2417 put_page(dirty_page);
2421 page_cache_release(new_page);
2422 return VM_FAULT_OOM;
2426 * do_no_pfn() tries to create a new page mapping for a page without
2427 * a struct_page backing it
2429 * As this is called only for pages that do not currently exist, we
2430 * do not need to flush old virtual caches or the TLB.
2432 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2433 * but allow concurrent faults), and pte mapped but not yet locked.
2434 * We return with mmap_sem still held, but pte unmapped and unlocked.
2436 * It is expected that the ->nopfn handler always returns the same pfn
2437 * for a given virtual mapping.
2439 * Mark this `noinline' to prevent it from bloating the main pagefault code.
2441 static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma,
2442 unsigned long address, pte_t *page_table, pmd_t *pmd,
2448 int ret = VM_FAULT_MINOR;
2450 pte_unmap(page_table);
2451 BUG_ON(!(vma->vm_flags & VM_PFNMAP));
2452 BUG_ON(is_cow_mapping(vma->vm_flags));
2454 pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK);
2455 if (unlikely(pfn == NOPFN_OOM))
2456 return VM_FAULT_OOM;
2457 else if (unlikely(pfn == NOPFN_SIGBUS))
2458 return VM_FAULT_SIGBUS;
2459 else if (unlikely(pfn == NOPFN_REFAULT))
2460 return VM_FAULT_MINOR;
2462 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2464 /* Only go through if we didn't race with anybody else... */
2465 if (pte_none(*page_table)) {
2466 entry = pfn_pte(pfn, vma->vm_page_prot);
2468 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2469 set_pte_at(mm, address, page_table, entry);
2471 pte_unmap_unlock(page_table, ptl);
2476 * Fault of a previously existing named mapping. Repopulate the pte
2477 * from the encoded file_pte if possible. This enables swappable
2480 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2481 * but allow concurrent faults), and pte mapped but not yet locked.
2482 * We return with mmap_sem still held, but pte unmapped and unlocked.
2484 static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
2485 unsigned long address, pte_t *page_table, pmd_t *pmd,
2486 int write_access, pte_t orig_pte)
2491 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2492 return VM_FAULT_MINOR;
2494 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
2496 * Page table corrupted: show pte and kill process.
2498 print_bad_pte(vma, orig_pte, address);
2499 return VM_FAULT_OOM;
2501 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2503 pgoff = pte_to_pgoff(orig_pte);
2504 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
2505 vma->vm_page_prot, pgoff, 0);
2507 return VM_FAULT_OOM;
2509 return VM_FAULT_SIGBUS;
2510 return VM_FAULT_MAJOR;
2514 * These routines also need to handle stuff like marking pages dirty
2515 * and/or accessed for architectures that don't do it in hardware (most
2516 * RISC architectures). The early dirtying is also good on the i386.
2518 * There is also a hook called "update_mmu_cache()" that architectures
2519 * with external mmu caches can use to update those (ie the Sparc or
2520 * PowerPC hashed page tables that act as extended TLBs).
2522 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2523 * but allow concurrent faults), and pte mapped but not yet locked.
2524 * We return with mmap_sem still held, but pte unmapped and unlocked.
2526 static inline int handle_pte_fault(struct mm_struct *mm,
2527 struct vm_area_struct *vma, unsigned long address,
2528 pte_t *pte, pmd_t *pmd, int write_access)
2534 if (!pte_present(entry)) {
2535 if (pte_none(entry)) {
2537 if (vma->vm_ops->nopage)
2538 return do_no_page(mm, vma, address,
2541 if (unlikely(vma->vm_ops->nopfn))
2542 return do_no_pfn(mm, vma, address, pte,
2545 return do_anonymous_page(mm, vma, address,
2546 pte, pmd, write_access);
2548 if (pte_file(entry))
2549 return do_file_page(mm, vma, address,
2550 pte, pmd, write_access, entry);
2551 return do_swap_page(mm, vma, address,
2552 pte, pmd, write_access, entry);
2555 ptl = pte_lockptr(mm, pmd);
2557 if (unlikely(!pte_same(*pte, entry)))
2560 if (!pte_write(entry))
2561 return do_wp_page(mm, vma, address,
2562 pte, pmd, ptl, entry);
2563 entry = pte_mkdirty(entry);
2565 entry = pte_mkyoung(entry);
2566 if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
2567 update_mmu_cache(vma, address, entry);
2568 lazy_mmu_prot_update(entry);
2571 * This is needed only for protection faults but the arch code
2572 * is not yet telling us if this is a protection fault or not.
2573 * This still avoids useless tlb flushes for .text page faults
2577 flush_tlb_page(vma, address);
2580 pte_unmap_unlock(pte, ptl);
2581 return VM_FAULT_MINOR;
2585 * By the time we get here, we already hold the mm semaphore
2587 int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2588 unsigned long address, int write_access)
2595 __set_current_state(TASK_RUNNING);
2597 count_vm_event(PGFAULT);
2599 if (unlikely(is_vm_hugetlb_page(vma)))
2600 return hugetlb_fault(mm, vma, address, write_access);
2602 pgd = pgd_offset(mm, address);
2603 pud = pud_alloc(mm, pgd, address);
2605 return VM_FAULT_OOM;
2606 pmd = pmd_alloc(mm, pud, address);
2608 return VM_FAULT_OOM;
2609 pte = pte_alloc_map(mm, pmd, address);
2611 return VM_FAULT_OOM;
2613 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
2616 EXPORT_SYMBOL_GPL(__handle_mm_fault);
2618 #ifndef __PAGETABLE_PUD_FOLDED
2620 * Allocate page upper directory.
2621 * We've already handled the fast-path in-line.
2623 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2625 pud_t *new = pud_alloc_one(mm, address);
2629 spin_lock(&mm->page_table_lock);
2630 if (pgd_present(*pgd)) /* Another has populated it */
2633 pgd_populate(mm, pgd, new);
2634 spin_unlock(&mm->page_table_lock);
2637 #endif /* __PAGETABLE_PUD_FOLDED */
2639 #ifndef __PAGETABLE_PMD_FOLDED
2641 * Allocate page middle directory.
2642 * We've already handled the fast-path in-line.
2644 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2646 pmd_t *new = pmd_alloc_one(mm, address);
2650 spin_lock(&mm->page_table_lock);
2651 #ifndef __ARCH_HAS_4LEVEL_HACK
2652 if (pud_present(*pud)) /* Another has populated it */
2655 pud_populate(mm, pud, new);
2657 if (pgd_present(*pud)) /* Another has populated it */
2660 pgd_populate(mm, pud, new);
2661 #endif /* __ARCH_HAS_4LEVEL_HACK */
2662 spin_unlock(&mm->page_table_lock);
2665 #endif /* __PAGETABLE_PMD_FOLDED */
2667 int make_pages_present(unsigned long addr, unsigned long end)
2669 int ret, len, write;
2670 struct vm_area_struct * vma;
2672 vma = find_vma(current->mm, addr);
2675 write = (vma->vm_flags & VM_WRITE) != 0;
2676 BUG_ON(addr >= end);
2677 BUG_ON(end > vma->vm_end);
2678 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2679 ret = get_user_pages(current, current->mm, addr,
2680 len, write, 0, NULL, NULL);
2683 return ret == len ? 0 : -1;
2687 * Map a vmalloc()-space virtual address to the physical page.
2689 struct page * vmalloc_to_page(void * vmalloc_addr)
2691 unsigned long addr = (unsigned long) vmalloc_addr;
2692 struct page *page = NULL;
2693 pgd_t *pgd = pgd_offset_k(addr);
2698 if (!pgd_none(*pgd)) {
2699 pud = pud_offset(pgd, addr);
2700 if (!pud_none(*pud)) {
2701 pmd = pmd_offset(pud, addr);
2702 if (!pmd_none(*pmd)) {
2703 ptep = pte_offset_map(pmd, addr);
2705 if (pte_present(pte))
2706 page = pte_page(pte);
2714 EXPORT_SYMBOL(vmalloc_to_page);
2717 * Map a vmalloc()-space virtual address to the physical page frame number.
2719 unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2721 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2724 EXPORT_SYMBOL(vmalloc_to_pfn);
2726 #if !defined(__HAVE_ARCH_GATE_AREA)
2728 #if defined(AT_SYSINFO_EHDR)
2729 static struct vm_area_struct gate_vma;
2731 static int __init gate_vma_init(void)
2733 gate_vma.vm_mm = NULL;
2734 gate_vma.vm_start = FIXADDR_USER_START;
2735 gate_vma.vm_end = FIXADDR_USER_END;
2736 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
2737 gate_vma.vm_page_prot = __P101;
2739 * Make sure the vDSO gets into every core dump.
2740 * Dumping its contents makes post-mortem fully interpretable later
2741 * without matching up the same kernel and hardware config to see
2742 * what PC values meant.
2744 gate_vma.vm_flags |= VM_ALWAYSDUMP;
2747 __initcall(gate_vma_init);
2750 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2752 #ifdef AT_SYSINFO_EHDR
2759 int in_gate_area_no_task(unsigned long addr)
2761 #ifdef AT_SYSINFO_EHDR
2762 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2768 #endif /* __HAVE_ARCH_GATE_AREA */
2771 * Access another process' address space.
2772 * Source/target buffer must be kernel space,
2773 * Do not walk the page table directly, use get_user_pages
2775 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2777 struct mm_struct *mm;
2778 struct vm_area_struct *vma;
2780 void *old_buf = buf;
2782 mm = get_task_mm(tsk);
2786 down_read(&mm->mmap_sem);
2787 /* ignore errors, just check how much was sucessfully transfered */
2789 int bytes, ret, offset;
2792 ret = get_user_pages(tsk, mm, addr, 1,
2793 write, 1, &page, &vma);
2798 offset = addr & (PAGE_SIZE-1);
2799 if (bytes > PAGE_SIZE-offset)
2800 bytes = PAGE_SIZE-offset;
2804 copy_to_user_page(vma, page, addr,
2805 maddr + offset, buf, bytes);
2806 set_page_dirty_lock(page);
2808 copy_from_user_page(vma, page, addr,
2809 buf, maddr + offset, bytes);
2812 page_cache_release(page);
2817 up_read(&mm->mmap_sem);
2820 return buf - old_buf;