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/ksm.h>
49 #include <linux/rmap.h>
50 #include <linux/module.h>
51 #include <linux/delayacct.h>
52 #include <linux/init.h>
53 #include <linux/writeback.h>
54 #include <linux/memcontrol.h>
55 #include <linux/mmu_notifier.h>
56 #include <linux/kallsyms.h>
57 #include <linux/swapops.h>
58 #include <linux/elf.h>
61 #include <asm/pgalloc.h>
62 #include <asm/uaccess.h>
64 #include <asm/tlbflush.h>
65 #include <asm/pgtable.h>
69 #ifndef CONFIG_NEED_MULTIPLE_NODES
70 /* use the per-pgdat data instead for discontigmem - mbligh */
71 unsigned long max_mapnr;
74 EXPORT_SYMBOL(max_mapnr);
75 EXPORT_SYMBOL(mem_map);
78 unsigned long num_physpages;
80 * A number of key systems in x86 including ioremap() rely on the assumption
81 * that high_memory defines the upper bound on direct map memory, then end
82 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
83 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
88 EXPORT_SYMBOL(num_physpages);
89 EXPORT_SYMBOL(high_memory);
92 * Randomize the address space (stacks, mmaps, brk, etc.).
94 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
95 * as ancient (libc5 based) binaries can segfault. )
97 int randomize_va_space __read_mostly =
98 #ifdef CONFIG_COMPAT_BRK
104 static int __init disable_randmaps(char *s)
106 randomize_va_space = 0;
109 __setup("norandmaps", disable_randmaps);
111 unsigned long zero_pfn __read_mostly;
112 unsigned long highest_memmap_pfn __read_mostly;
115 * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
117 static int __init init_zero_pfn(void)
119 zero_pfn = page_to_pfn(ZERO_PAGE(0));
122 core_initcall(init_zero_pfn);
125 #if defined(SPLIT_RSS_COUNTING)
127 void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm)
131 for (i = 0; i < NR_MM_COUNTERS; i++) {
132 if (task->rss_stat.count[i]) {
133 add_mm_counter(mm, i, task->rss_stat.count[i]);
134 task->rss_stat.count[i] = 0;
137 task->rss_stat.events = 0;
140 static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
142 struct task_struct *task = current;
144 if (likely(task->mm == mm))
145 task->rss_stat.count[member] += val;
147 add_mm_counter(mm, member, val);
149 #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
150 #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
152 /* sync counter once per 64 page faults */
153 #define TASK_RSS_EVENTS_THRESH (64)
154 static void check_sync_rss_stat(struct task_struct *task)
156 if (unlikely(task != current))
158 if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
159 __sync_task_rss_stat(task, task->mm);
162 unsigned long get_mm_counter(struct mm_struct *mm, int member)
167 * Don't use task->mm here...for avoiding to use task_get_mm()..
168 * The caller must guarantee task->mm is not invalid.
170 val = atomic_long_read(&mm->rss_stat.count[member]);
172 * counter is updated in asynchronous manner and may go to minus.
173 * But it's never be expected number for users.
177 return (unsigned long)val;
180 void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
182 __sync_task_rss_stat(task, mm);
186 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
187 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
189 static void check_sync_rss_stat(struct task_struct *task)
196 * If a p?d_bad entry is found while walking page tables, report
197 * the error, before resetting entry to p?d_none. Usually (but
198 * very seldom) called out from the p?d_none_or_clear_bad macros.
201 void pgd_clear_bad(pgd_t *pgd)
207 void pud_clear_bad(pud_t *pud)
213 void pmd_clear_bad(pmd_t *pmd)
220 * Note: this doesn't free the actual pages themselves. That
221 * has been handled earlier when unmapping all the memory regions.
223 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
226 pgtable_t token = pmd_pgtable(*pmd);
228 pte_free_tlb(tlb, token, addr);
232 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
233 unsigned long addr, unsigned long end,
234 unsigned long floor, unsigned long ceiling)
241 pmd = pmd_offset(pud, addr);
243 next = pmd_addr_end(addr, end);
244 if (pmd_none_or_clear_bad(pmd))
246 free_pte_range(tlb, pmd, addr);
247 } while (pmd++, addr = next, addr != end);
257 if (end - 1 > ceiling - 1)
260 pmd = pmd_offset(pud, start);
262 pmd_free_tlb(tlb, pmd, start);
265 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
266 unsigned long addr, unsigned long end,
267 unsigned long floor, unsigned long ceiling)
274 pud = pud_offset(pgd, addr);
276 next = pud_addr_end(addr, end);
277 if (pud_none_or_clear_bad(pud))
279 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
280 } while (pud++, addr = next, addr != end);
286 ceiling &= PGDIR_MASK;
290 if (end - 1 > ceiling - 1)
293 pud = pud_offset(pgd, start);
295 pud_free_tlb(tlb, pud, start);
299 * This function frees user-level page tables of a process.
301 * Must be called with pagetable lock held.
303 void free_pgd_range(struct mmu_gather *tlb,
304 unsigned long addr, unsigned long end,
305 unsigned long floor, unsigned long ceiling)
312 * The next few lines have given us lots of grief...
314 * Why are we testing PMD* at this top level? Because often
315 * there will be no work to do at all, and we'd prefer not to
316 * go all the way down to the bottom just to discover that.
318 * Why all these "- 1"s? Because 0 represents both the bottom
319 * of the address space and the top of it (using -1 for the
320 * top wouldn't help much: the masks would do the wrong thing).
321 * The rule is that addr 0 and floor 0 refer to the bottom of
322 * the address space, but end 0 and ceiling 0 refer to the top
323 * Comparisons need to use "end - 1" and "ceiling - 1" (though
324 * that end 0 case should be mythical).
326 * Wherever addr is brought up or ceiling brought down, we must
327 * be careful to reject "the opposite 0" before it confuses the
328 * subsequent tests. But what about where end is brought down
329 * by PMD_SIZE below? no, end can't go down to 0 there.
331 * Whereas we round start (addr) and ceiling down, by different
332 * masks at different levels, in order to test whether a table
333 * now has no other vmas using it, so can be freed, we don't
334 * bother to round floor or end up - the tests don't need that.
348 if (end - 1 > ceiling - 1)
354 pgd = pgd_offset(tlb->mm, addr);
356 next = pgd_addr_end(addr, end);
357 if (pgd_none_or_clear_bad(pgd))
359 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
360 } while (pgd++, addr = next, addr != end);
363 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
364 unsigned long floor, unsigned long ceiling)
367 struct vm_area_struct *next = vma->vm_next;
368 unsigned long addr = vma->vm_start;
371 * Hide vma from rmap and truncate_pagecache before freeing
374 unlink_anon_vmas(vma);
375 unlink_file_vma(vma);
377 if (is_vm_hugetlb_page(vma)) {
378 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
379 floor, next? next->vm_start: ceiling);
382 * Optimization: gather nearby vmas into one call down
384 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
385 && !is_vm_hugetlb_page(next)) {
388 unlink_anon_vmas(vma);
389 unlink_file_vma(vma);
391 free_pgd_range(tlb, addr, vma->vm_end,
392 floor, next? next->vm_start: ceiling);
398 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
400 pgtable_t new = pte_alloc_one(mm, address);
405 * Ensure all pte setup (eg. pte page lock and page clearing) are
406 * visible before the pte is made visible to other CPUs by being
407 * put into page tables.
409 * The other side of the story is the pointer chasing in the page
410 * table walking code (when walking the page table without locking;
411 * ie. most of the time). Fortunately, these data accesses consist
412 * of a chain of data-dependent loads, meaning most CPUs (alpha
413 * being the notable exception) will already guarantee loads are
414 * seen in-order. See the alpha page table accessors for the
415 * smp_read_barrier_depends() barriers in page table walking code.
417 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
419 spin_lock(&mm->page_table_lock);
420 if (!pmd_present(*pmd)) { /* Has another populated it ? */
422 pmd_populate(mm, pmd, new);
425 spin_unlock(&mm->page_table_lock);
431 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
433 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
437 smp_wmb(); /* See comment in __pte_alloc */
439 spin_lock(&init_mm.page_table_lock);
440 if (!pmd_present(*pmd)) { /* Has another populated it ? */
441 pmd_populate_kernel(&init_mm, pmd, new);
444 spin_unlock(&init_mm.page_table_lock);
446 pte_free_kernel(&init_mm, new);
450 static inline void init_rss_vec(int *rss)
452 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
455 static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
459 if (current->mm == mm)
460 sync_mm_rss(current, mm);
461 for (i = 0; i < NR_MM_COUNTERS; i++)
463 add_mm_counter(mm, i, rss[i]);
467 * This function is called to print an error when a bad pte
468 * is found. For example, we might have a PFN-mapped pte in
469 * a region that doesn't allow it.
471 * The calling function must still handle the error.
473 static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
474 pte_t pte, struct page *page)
476 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
477 pud_t *pud = pud_offset(pgd, addr);
478 pmd_t *pmd = pmd_offset(pud, addr);
479 struct address_space *mapping;
481 static unsigned long resume;
482 static unsigned long nr_shown;
483 static unsigned long nr_unshown;
486 * Allow a burst of 60 reports, then keep quiet for that minute;
487 * or allow a steady drip of one report per second.
489 if (nr_shown == 60) {
490 if (time_before(jiffies, resume)) {
496 "BUG: Bad page map: %lu messages suppressed\n",
503 resume = jiffies + 60 * HZ;
505 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
506 index = linear_page_index(vma, addr);
509 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
511 (long long)pte_val(pte), (long long)pmd_val(*pmd));
514 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
515 page, (void *)page->flags, page_count(page),
516 page_mapcount(page), page->mapping, page->index);
519 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
520 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
522 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
525 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
526 (unsigned long)vma->vm_ops->fault);
527 if (vma->vm_file && vma->vm_file->f_op)
528 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
529 (unsigned long)vma->vm_file->f_op->mmap);
531 add_taint(TAINT_BAD_PAGE);
534 static inline int is_cow_mapping(unsigned int flags)
536 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
540 static inline int is_zero_pfn(unsigned long pfn)
542 return pfn == zero_pfn;
547 static inline unsigned long my_zero_pfn(unsigned long addr)
554 * vm_normal_page -- This function gets the "struct page" associated with a pte.
556 * "Special" mappings do not wish to be associated with a "struct page" (either
557 * it doesn't exist, or it exists but they don't want to touch it). In this
558 * case, NULL is returned here. "Normal" mappings do have a struct page.
560 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
561 * pte bit, in which case this function is trivial. Secondly, an architecture
562 * may not have a spare pte bit, which requires a more complicated scheme,
565 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
566 * special mapping (even if there are underlying and valid "struct pages").
567 * COWed pages of a VM_PFNMAP are always normal.
569 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
570 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
571 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
572 * mapping will always honor the rule
574 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
576 * And for normal mappings this is false.
578 * This restricts such mappings to be a linear translation from virtual address
579 * to pfn. To get around this restriction, we allow arbitrary mappings so long
580 * as the vma is not a COW mapping; in that case, we know that all ptes are
581 * special (because none can have been COWed).
584 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
586 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
587 * page" backing, however the difference is that _all_ pages with a struct
588 * page (that is, those where pfn_valid is true) are refcounted and considered
589 * normal pages by the VM. The disadvantage is that pages are refcounted
590 * (which can be slower and simply not an option for some PFNMAP users). The
591 * advantage is that we don't have to follow the strict linearity rule of
592 * PFNMAP mappings in order to support COWable mappings.
595 #ifdef __HAVE_ARCH_PTE_SPECIAL
596 # define HAVE_PTE_SPECIAL 1
598 # define HAVE_PTE_SPECIAL 0
600 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
603 unsigned long pfn = pte_pfn(pte);
605 if (HAVE_PTE_SPECIAL) {
606 if (likely(!pte_special(pte)))
608 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
610 if (!is_zero_pfn(pfn))
611 print_bad_pte(vma, addr, pte, NULL);
615 /* !HAVE_PTE_SPECIAL case follows: */
617 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
618 if (vma->vm_flags & VM_MIXEDMAP) {
624 off = (addr - vma->vm_start) >> PAGE_SHIFT;
625 if (pfn == vma->vm_pgoff + off)
627 if (!is_cow_mapping(vma->vm_flags))
632 if (is_zero_pfn(pfn))
635 if (unlikely(pfn > highest_memmap_pfn)) {
636 print_bad_pte(vma, addr, pte, NULL);
641 * NOTE! We still have PageReserved() pages in the page tables.
642 * eg. VDSO mappings can cause them to exist.
645 return pfn_to_page(pfn);
649 * copy one vm_area from one task to the other. Assumes the page tables
650 * already present in the new task to be cleared in the whole range
651 * covered by this vma.
654 static inline unsigned long
655 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
656 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
657 unsigned long addr, int *rss)
659 unsigned long vm_flags = vma->vm_flags;
660 pte_t pte = *src_pte;
663 /* pte contains position in swap or file, so copy. */
664 if (unlikely(!pte_present(pte))) {
665 if (!pte_file(pte)) {
666 swp_entry_t entry = pte_to_swp_entry(pte);
668 if (swap_duplicate(entry) < 0)
671 /* make sure dst_mm is on swapoff's mmlist. */
672 if (unlikely(list_empty(&dst_mm->mmlist))) {
673 spin_lock(&mmlist_lock);
674 if (list_empty(&dst_mm->mmlist))
675 list_add(&dst_mm->mmlist,
677 spin_unlock(&mmlist_lock);
679 if (likely(!non_swap_entry(entry)))
681 else if (is_write_migration_entry(entry) &&
682 is_cow_mapping(vm_flags)) {
684 * COW mappings require pages in both parent
685 * and child to be set to read.
687 make_migration_entry_read(&entry);
688 pte = swp_entry_to_pte(entry);
689 set_pte_at(src_mm, addr, src_pte, pte);
696 * If it's a COW mapping, write protect it both
697 * in the parent and the child
699 if (is_cow_mapping(vm_flags)) {
700 ptep_set_wrprotect(src_mm, addr, src_pte);
701 pte = pte_wrprotect(pte);
705 * If it's a shared mapping, mark it clean in
708 if (vm_flags & VM_SHARED)
709 pte = pte_mkclean(pte);
710 pte = pte_mkold(pte);
712 page = vm_normal_page(vma, addr, pte);
723 set_pte_at(dst_mm, addr, dst_pte, pte);
727 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
728 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
729 unsigned long addr, unsigned long end)
731 pte_t *orig_src_pte, *orig_dst_pte;
732 pte_t *src_pte, *dst_pte;
733 spinlock_t *src_ptl, *dst_ptl;
735 int rss[NR_MM_COUNTERS];
736 swp_entry_t entry = (swp_entry_t){0};
741 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
744 src_pte = pte_offset_map_nested(src_pmd, addr);
745 src_ptl = pte_lockptr(src_mm, src_pmd);
746 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
747 orig_src_pte = src_pte;
748 orig_dst_pte = dst_pte;
749 arch_enter_lazy_mmu_mode();
753 * We are holding two locks at this point - either of them
754 * could generate latencies in another task on another CPU.
756 if (progress >= 32) {
758 if (need_resched() ||
759 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
762 if (pte_none(*src_pte)) {
766 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
771 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
773 arch_leave_lazy_mmu_mode();
774 spin_unlock(src_ptl);
775 pte_unmap_nested(orig_src_pte);
776 add_mm_rss_vec(dst_mm, rss);
777 pte_unmap_unlock(orig_dst_pte, dst_ptl);
781 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
790 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
791 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
792 unsigned long addr, unsigned long end)
794 pmd_t *src_pmd, *dst_pmd;
797 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
800 src_pmd = pmd_offset(src_pud, addr);
802 next = pmd_addr_end(addr, end);
803 if (pmd_none_or_clear_bad(src_pmd))
805 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
808 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
812 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
813 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
814 unsigned long addr, unsigned long end)
816 pud_t *src_pud, *dst_pud;
819 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
822 src_pud = pud_offset(src_pgd, addr);
824 next = pud_addr_end(addr, end);
825 if (pud_none_or_clear_bad(src_pud))
827 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
830 } while (dst_pud++, src_pud++, addr = next, addr != end);
834 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
835 struct vm_area_struct *vma)
837 pgd_t *src_pgd, *dst_pgd;
839 unsigned long addr = vma->vm_start;
840 unsigned long end = vma->vm_end;
844 * Don't copy ptes where a page fault will fill them correctly.
845 * Fork becomes much lighter when there are big shared or private
846 * readonly mappings. The tradeoff is that copy_page_range is more
847 * efficient than faulting.
849 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
854 if (is_vm_hugetlb_page(vma))
855 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
857 if (unlikely(is_pfn_mapping(vma))) {
859 * We do not free on error cases below as remove_vma
860 * gets called on error from higher level routine
862 ret = track_pfn_vma_copy(vma);
868 * We need to invalidate the secondary MMU mappings only when
869 * there could be a permission downgrade on the ptes of the
870 * parent mm. And a permission downgrade will only happen if
871 * is_cow_mapping() returns true.
873 if (is_cow_mapping(vma->vm_flags))
874 mmu_notifier_invalidate_range_start(src_mm, addr, end);
877 dst_pgd = pgd_offset(dst_mm, addr);
878 src_pgd = pgd_offset(src_mm, addr);
880 next = pgd_addr_end(addr, end);
881 if (pgd_none_or_clear_bad(src_pgd))
883 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
888 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
890 if (is_cow_mapping(vma->vm_flags))
891 mmu_notifier_invalidate_range_end(src_mm,
896 static unsigned long zap_pte_range(struct mmu_gather *tlb,
897 struct vm_area_struct *vma, pmd_t *pmd,
898 unsigned long addr, unsigned long end,
899 long *zap_work, struct zap_details *details)
901 struct mm_struct *mm = tlb->mm;
904 int rss[NR_MM_COUNTERS];
908 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
909 arch_enter_lazy_mmu_mode();
912 if (pte_none(ptent)) {
917 (*zap_work) -= PAGE_SIZE;
919 if (pte_present(ptent)) {
922 page = vm_normal_page(vma, addr, ptent);
923 if (unlikely(details) && page) {
925 * unmap_shared_mapping_pages() wants to
926 * invalidate cache without truncating:
927 * unmap shared but keep private pages.
929 if (details->check_mapping &&
930 details->check_mapping != page->mapping)
933 * Each page->index must be checked when
934 * invalidating or truncating nonlinear.
936 if (details->nonlinear_vma &&
937 (page->index < details->first_index ||
938 page->index > details->last_index))
941 ptent = ptep_get_and_clear_full(mm, addr, pte,
943 tlb_remove_tlb_entry(tlb, pte, addr);
946 if (unlikely(details) && details->nonlinear_vma
947 && linear_page_index(details->nonlinear_vma,
948 addr) != page->index)
949 set_pte_at(mm, addr, pte,
950 pgoff_to_pte(page->index));
954 if (pte_dirty(ptent))
955 set_page_dirty(page);
956 if (pte_young(ptent) &&
957 likely(!VM_SequentialReadHint(vma)))
958 mark_page_accessed(page);
961 page_remove_rmap(page);
962 if (unlikely(page_mapcount(page) < 0))
963 print_bad_pte(vma, addr, ptent, page);
964 tlb_remove_page(tlb, page);
968 * If details->check_mapping, we leave swap entries;
969 * if details->nonlinear_vma, we leave file entries.
971 if (unlikely(details))
973 if (pte_file(ptent)) {
974 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
975 print_bad_pte(vma, addr, ptent, NULL);
977 swp_entry_t entry = pte_to_swp_entry(ptent);
979 if (!non_swap_entry(entry))
981 if (unlikely(!free_swap_and_cache(entry)))
982 print_bad_pte(vma, addr, ptent, NULL);
984 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
985 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
987 add_mm_rss_vec(mm, rss);
988 arch_leave_lazy_mmu_mode();
989 pte_unmap_unlock(pte - 1, ptl);
994 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
995 struct vm_area_struct *vma, pud_t *pud,
996 unsigned long addr, unsigned long end,
997 long *zap_work, struct zap_details *details)
1002 pmd = pmd_offset(pud, addr);
1004 next = pmd_addr_end(addr, end);
1005 if (pmd_none_or_clear_bad(pmd)) {
1009 next = zap_pte_range(tlb, vma, pmd, addr, next,
1011 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
1016 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1017 struct vm_area_struct *vma, pgd_t *pgd,
1018 unsigned long addr, unsigned long end,
1019 long *zap_work, struct zap_details *details)
1024 pud = pud_offset(pgd, addr);
1026 next = pud_addr_end(addr, end);
1027 if (pud_none_or_clear_bad(pud)) {
1031 next = zap_pmd_range(tlb, vma, pud, addr, next,
1033 } while (pud++, addr = next, (addr != end && *zap_work > 0));
1038 static unsigned long unmap_page_range(struct mmu_gather *tlb,
1039 struct vm_area_struct *vma,
1040 unsigned long addr, unsigned long end,
1041 long *zap_work, struct zap_details *details)
1046 if (details && !details->check_mapping && !details->nonlinear_vma)
1049 BUG_ON(addr >= end);
1050 mem_cgroup_uncharge_start();
1051 tlb_start_vma(tlb, vma);
1052 pgd = pgd_offset(vma->vm_mm, addr);
1054 next = pgd_addr_end(addr, end);
1055 if (pgd_none_or_clear_bad(pgd)) {
1059 next = zap_pud_range(tlb, vma, pgd, addr, next,
1061 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
1062 tlb_end_vma(tlb, vma);
1063 mem_cgroup_uncharge_end();
1068 #ifdef CONFIG_PREEMPT
1069 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
1071 /* No preempt: go for improved straight-line efficiency */
1072 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
1076 * unmap_vmas - unmap a range of memory covered by a list of vma's
1077 * @tlbp: address of the caller's struct mmu_gather
1078 * @vma: the starting vma
1079 * @start_addr: virtual address at which to start unmapping
1080 * @end_addr: virtual address at which to end unmapping
1081 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
1082 * @details: details of nonlinear truncation or shared cache invalidation
1084 * Returns the end address of the unmapping (restart addr if interrupted).
1086 * Unmap all pages in the vma list.
1088 * We aim to not hold locks for too long (for scheduling latency reasons).
1089 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
1090 * return the ending mmu_gather to the caller.
1092 * Only addresses between `start' and `end' will be unmapped.
1094 * The VMA list must be sorted in ascending virtual address order.
1096 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1097 * range after unmap_vmas() returns. So the only responsibility here is to
1098 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1099 * drops the lock and schedules.
1101 unsigned long unmap_vmas(struct mmu_gather **tlbp,
1102 struct vm_area_struct *vma, unsigned long start_addr,
1103 unsigned long end_addr, unsigned long *nr_accounted,
1104 struct zap_details *details)
1106 long zap_work = ZAP_BLOCK_SIZE;
1107 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
1108 int tlb_start_valid = 0;
1109 unsigned long start = start_addr;
1110 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
1111 int fullmm = (*tlbp)->fullmm;
1112 struct mm_struct *mm = vma->vm_mm;
1114 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1115 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
1118 start = max(vma->vm_start, start_addr);
1119 if (start >= vma->vm_end)
1121 end = min(vma->vm_end, end_addr);
1122 if (end <= vma->vm_start)
1125 if (vma->vm_flags & VM_ACCOUNT)
1126 *nr_accounted += (end - start) >> PAGE_SHIFT;
1128 if (unlikely(is_pfn_mapping(vma)))
1129 untrack_pfn_vma(vma, 0, 0);
1131 while (start != end) {
1132 if (!tlb_start_valid) {
1134 tlb_start_valid = 1;
1137 if (unlikely(is_vm_hugetlb_page(vma))) {
1139 * It is undesirable to test vma->vm_file as it
1140 * should be non-null for valid hugetlb area.
1141 * However, vm_file will be NULL in the error
1142 * cleanup path of do_mmap_pgoff. When
1143 * hugetlbfs ->mmap method fails,
1144 * do_mmap_pgoff() nullifies vma->vm_file
1145 * before calling this function to clean up.
1146 * Since no pte has actually been setup, it is
1147 * safe to do nothing in this case.
1150 unmap_hugepage_range(vma, start, end, NULL);
1151 zap_work -= (end - start) /
1152 pages_per_huge_page(hstate_vma(vma));
1157 start = unmap_page_range(*tlbp, vma,
1158 start, end, &zap_work, details);
1161 BUG_ON(start != end);
1165 tlb_finish_mmu(*tlbp, tlb_start, start);
1167 if (need_resched() ||
1168 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
1176 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
1177 tlb_start_valid = 0;
1178 zap_work = ZAP_BLOCK_SIZE;
1182 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1183 return start; /* which is now the end (or restart) address */
1187 * zap_page_range - remove user pages in a given range
1188 * @vma: vm_area_struct holding the applicable pages
1189 * @address: starting address of pages to zap
1190 * @size: number of bytes to zap
1191 * @details: details of nonlinear truncation or shared cache invalidation
1193 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
1194 unsigned long size, struct zap_details *details)
1196 struct mm_struct *mm = vma->vm_mm;
1197 struct mmu_gather *tlb;
1198 unsigned long end = address + size;
1199 unsigned long nr_accounted = 0;
1202 tlb = tlb_gather_mmu(mm, 0);
1203 update_hiwater_rss(mm);
1204 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
1206 tlb_finish_mmu(tlb, address, end);
1211 * zap_vma_ptes - remove ptes mapping the vma
1212 * @vma: vm_area_struct holding ptes to be zapped
1213 * @address: starting address of pages to zap
1214 * @size: number of bytes to zap
1216 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1218 * The entire address range must be fully contained within the vma.
1220 * Returns 0 if successful.
1222 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1225 if (address < vma->vm_start || address + size > vma->vm_end ||
1226 !(vma->vm_flags & VM_PFNMAP))
1228 zap_page_range(vma, address, size, NULL);
1231 EXPORT_SYMBOL_GPL(zap_vma_ptes);
1234 * Do a quick page-table lookup for a single page.
1236 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1245 struct mm_struct *mm = vma->vm_mm;
1247 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1248 if (!IS_ERR(page)) {
1249 BUG_ON(flags & FOLL_GET);
1254 pgd = pgd_offset(mm, address);
1255 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1258 pud = pud_offset(pgd, address);
1261 if (pud_huge(*pud)) {
1262 BUG_ON(flags & FOLL_GET);
1263 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1266 if (unlikely(pud_bad(*pud)))
1269 pmd = pmd_offset(pud, address);
1272 if (pmd_huge(*pmd)) {
1273 BUG_ON(flags & FOLL_GET);
1274 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1277 if (unlikely(pmd_bad(*pmd)))
1280 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1283 if (!pte_present(pte))
1285 if ((flags & FOLL_WRITE) && !pte_write(pte))
1288 page = vm_normal_page(vma, address, pte);
1289 if (unlikely(!page)) {
1290 if ((flags & FOLL_DUMP) ||
1291 !is_zero_pfn(pte_pfn(pte)))
1293 page = pte_page(pte);
1296 if (flags & FOLL_GET)
1298 if (flags & FOLL_TOUCH) {
1299 if ((flags & FOLL_WRITE) &&
1300 !pte_dirty(pte) && !PageDirty(page))
1301 set_page_dirty(page);
1303 * pte_mkyoung() would be more correct here, but atomic care
1304 * is needed to avoid losing the dirty bit: it is easier to use
1305 * mark_page_accessed().
1307 mark_page_accessed(page);
1310 pte_unmap_unlock(ptep, ptl);
1315 pte_unmap_unlock(ptep, ptl);
1316 return ERR_PTR(-EFAULT);
1319 pte_unmap_unlock(ptep, ptl);
1325 * When core dumping an enormous anonymous area that nobody
1326 * has touched so far, we don't want to allocate unnecessary pages or
1327 * page tables. Return error instead of NULL to skip handle_mm_fault,
1328 * then get_dump_page() will return NULL to leave a hole in the dump.
1329 * But we can only make this optimization where a hole would surely
1330 * be zero-filled if handle_mm_fault() actually did handle it.
1332 if ((flags & FOLL_DUMP) &&
1333 (!vma->vm_ops || !vma->vm_ops->fault))
1334 return ERR_PTR(-EFAULT);
1338 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1339 unsigned long start, int nr_pages, unsigned int gup_flags,
1340 struct page **pages, struct vm_area_struct **vmas)
1343 unsigned long vm_flags;
1348 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1351 * Require read or write permissions.
1352 * If FOLL_FORCE is set, we only require the "MAY" flags.
1354 vm_flags = (gup_flags & FOLL_WRITE) ?
1355 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1356 vm_flags &= (gup_flags & FOLL_FORCE) ?
1357 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1361 struct vm_area_struct *vma;
1363 vma = find_extend_vma(mm, start);
1364 if (!vma && in_gate_area(tsk, start)) {
1365 unsigned long pg = start & PAGE_MASK;
1366 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1372 /* user gate pages are read-only */
1373 if (gup_flags & FOLL_WRITE)
1374 return i ? : -EFAULT;
1376 pgd = pgd_offset_k(pg);
1378 pgd = pgd_offset_gate(mm, pg);
1379 BUG_ON(pgd_none(*pgd));
1380 pud = pud_offset(pgd, pg);
1381 BUG_ON(pud_none(*pud));
1382 pmd = pmd_offset(pud, pg);
1384 return i ? : -EFAULT;
1385 pte = pte_offset_map(pmd, pg);
1386 if (pte_none(*pte)) {
1388 return i ? : -EFAULT;
1391 struct page *page = vm_normal_page(gate_vma, start, *pte);
1406 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1407 !(vm_flags & vma->vm_flags))
1408 return i ? : -EFAULT;
1410 if (is_vm_hugetlb_page(vma)) {
1411 i = follow_hugetlb_page(mm, vma, pages, vmas,
1412 &start, &nr_pages, i, gup_flags);
1418 unsigned int foll_flags = gup_flags;
1421 * If we have a pending SIGKILL, don't keep faulting
1422 * pages and potentially allocating memory.
1424 if (unlikely(fatal_signal_pending(current)))
1425 return i ? i : -ERESTARTSYS;
1428 while (!(page = follow_page(vma, start, foll_flags))) {
1431 ret = handle_mm_fault(mm, vma, start,
1432 (foll_flags & FOLL_WRITE) ?
1433 FAULT_FLAG_WRITE : 0);
1435 if (ret & VM_FAULT_ERROR) {
1436 if (ret & VM_FAULT_OOM)
1437 return i ? i : -ENOMEM;
1439 (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
1440 return i ? i : -EFAULT;
1443 if (ret & VM_FAULT_MAJOR)
1449 * The VM_FAULT_WRITE bit tells us that
1450 * do_wp_page has broken COW when necessary,
1451 * even if maybe_mkwrite decided not to set
1452 * pte_write. We can thus safely do subsequent
1453 * page lookups as if they were reads. But only
1454 * do so when looping for pte_write is futile:
1455 * in some cases userspace may also be wanting
1456 * to write to the gotten user page, which a
1457 * read fault here might prevent (a readonly
1458 * page might get reCOWed by userspace write).
1460 if ((ret & VM_FAULT_WRITE) &&
1461 !(vma->vm_flags & VM_WRITE))
1462 foll_flags &= ~FOLL_WRITE;
1467 return i ? i : PTR_ERR(page);
1471 flush_anon_page(vma, page, start);
1472 flush_dcache_page(page);
1479 } while (nr_pages && start < vma->vm_end);
1485 * get_user_pages() - pin user pages in memory
1486 * @tsk: task_struct of target task
1487 * @mm: mm_struct of target mm
1488 * @start: starting user address
1489 * @nr_pages: number of pages from start to pin
1490 * @write: whether pages will be written to by the caller
1491 * @force: whether to force write access even if user mapping is
1492 * readonly. This will result in the page being COWed even
1493 * in MAP_SHARED mappings. You do not want this.
1494 * @pages: array that receives pointers to the pages pinned.
1495 * Should be at least nr_pages long. Or NULL, if caller
1496 * only intends to ensure the pages are faulted in.
1497 * @vmas: array of pointers to vmas corresponding to each page.
1498 * Or NULL if the caller does not require them.
1500 * Returns number of pages pinned. This may be fewer than the number
1501 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1502 * were pinned, returns -errno. Each page returned must be released
1503 * with a put_page() call when it is finished with. vmas will only
1504 * remain valid while mmap_sem is held.
1506 * Must be called with mmap_sem held for read or write.
1508 * get_user_pages walks a process's page tables and takes a reference to
1509 * each struct page that each user address corresponds to at a given
1510 * instant. That is, it takes the page that would be accessed if a user
1511 * thread accesses the given user virtual address at that instant.
1513 * This does not guarantee that the page exists in the user mappings when
1514 * get_user_pages returns, and there may even be a completely different
1515 * page there in some cases (eg. if mmapped pagecache has been invalidated
1516 * and subsequently re faulted). However it does guarantee that the page
1517 * won't be freed completely. And mostly callers simply care that the page
1518 * contains data that was valid *at some point in time*. Typically, an IO
1519 * or similar operation cannot guarantee anything stronger anyway because
1520 * locks can't be held over the syscall boundary.
1522 * If write=0, the page must not be written to. If the page is written to,
1523 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1524 * after the page is finished with, and before put_page is called.
1526 * get_user_pages is typically used for fewer-copy IO operations, to get a
1527 * handle on the memory by some means other than accesses via the user virtual
1528 * addresses. The pages may be submitted for DMA to devices or accessed via
1529 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1530 * use the correct cache flushing APIs.
1532 * See also get_user_pages_fast, for performance critical applications.
1534 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1535 unsigned long start, int nr_pages, int write, int force,
1536 struct page **pages, struct vm_area_struct **vmas)
1538 int flags = FOLL_TOUCH;
1543 flags |= FOLL_WRITE;
1545 flags |= FOLL_FORCE;
1547 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
1549 EXPORT_SYMBOL(get_user_pages);
1552 * get_dump_page() - pin user page in memory while writing it to core dump
1553 * @addr: user address
1555 * Returns struct page pointer of user page pinned for dump,
1556 * to be freed afterwards by page_cache_release() or put_page().
1558 * Returns NULL on any kind of failure - a hole must then be inserted into
1559 * the corefile, to preserve alignment with its headers; and also returns
1560 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
1561 * allowing a hole to be left in the corefile to save diskspace.
1563 * Called without mmap_sem, but after all other threads have been killed.
1565 #ifdef CONFIG_ELF_CORE
1566 struct page *get_dump_page(unsigned long addr)
1568 struct vm_area_struct *vma;
1571 if (__get_user_pages(current, current->mm, addr, 1,
1572 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
1574 flush_cache_page(vma, addr, page_to_pfn(page));
1577 #endif /* CONFIG_ELF_CORE */
1579 pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1582 pgd_t * pgd = pgd_offset(mm, addr);
1583 pud_t * pud = pud_alloc(mm, pgd, addr);
1585 pmd_t * pmd = pmd_alloc(mm, pud, addr);
1587 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1593 * This is the old fallback for page remapping.
1595 * For historical reasons, it only allows reserved pages. Only
1596 * old drivers should use this, and they needed to mark their
1597 * pages reserved for the old functions anyway.
1599 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1600 struct page *page, pgprot_t prot)
1602 struct mm_struct *mm = vma->vm_mm;
1611 flush_dcache_page(page);
1612 pte = get_locked_pte(mm, addr, &ptl);
1616 if (!pte_none(*pte))
1619 /* Ok, finally just insert the thing.. */
1621 inc_mm_counter_fast(mm, MM_FILEPAGES);
1622 page_add_file_rmap(page);
1623 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1626 pte_unmap_unlock(pte, ptl);
1629 pte_unmap_unlock(pte, ptl);
1635 * vm_insert_page - insert single page into user vma
1636 * @vma: user vma to map to
1637 * @addr: target user address of this page
1638 * @page: source kernel page
1640 * This allows drivers to insert individual pages they've allocated
1643 * The page has to be a nice clean _individual_ kernel allocation.
1644 * If you allocate a compound page, you need to have marked it as
1645 * such (__GFP_COMP), or manually just split the page up yourself
1646 * (see split_page()).
1648 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1649 * took an arbitrary page protection parameter. This doesn't allow
1650 * that. Your vma protection will have to be set up correctly, which
1651 * means that if you want a shared writable mapping, you'd better
1652 * ask for a shared writable mapping!
1654 * The page does not need to be reserved.
1656 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1659 if (addr < vma->vm_start || addr >= vma->vm_end)
1661 if (!page_count(page))
1663 vma->vm_flags |= VM_INSERTPAGE;
1664 return insert_page(vma, addr, page, vma->vm_page_prot);
1666 EXPORT_SYMBOL(vm_insert_page);
1668 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1669 unsigned long pfn, pgprot_t prot)
1671 struct mm_struct *mm = vma->vm_mm;
1677 pte = get_locked_pte(mm, addr, &ptl);
1681 if (!pte_none(*pte))
1684 /* Ok, finally just insert the thing.. */
1685 entry = pte_mkspecial(pfn_pte(pfn, prot));
1686 set_pte_at(mm, addr, pte, entry);
1687 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
1691 pte_unmap_unlock(pte, ptl);
1697 * vm_insert_pfn - insert single pfn into user vma
1698 * @vma: user vma to map to
1699 * @addr: target user address of this page
1700 * @pfn: source kernel pfn
1702 * Similar to vm_inert_page, this allows drivers to insert individual pages
1703 * they've allocated into a user vma. Same comments apply.
1705 * This function should only be called from a vm_ops->fault handler, and
1706 * in that case the handler should return NULL.
1708 * vma cannot be a COW mapping.
1710 * As this is called only for pages that do not currently exist, we
1711 * do not need to flush old virtual caches or the TLB.
1713 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1717 pgprot_t pgprot = vma->vm_page_prot;
1719 * Technically, architectures with pte_special can avoid all these
1720 * restrictions (same for remap_pfn_range). However we would like
1721 * consistency in testing and feature parity among all, so we should
1722 * try to keep these invariants in place for everybody.
1724 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1725 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1726 (VM_PFNMAP|VM_MIXEDMAP));
1727 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1728 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
1730 if (addr < vma->vm_start || addr >= vma->vm_end)
1732 if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
1735 ret = insert_pfn(vma, addr, pfn, pgprot);
1738 untrack_pfn_vma(vma, pfn, PAGE_SIZE);
1742 EXPORT_SYMBOL(vm_insert_pfn);
1744 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1747 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1749 if (addr < vma->vm_start || addr >= vma->vm_end)
1753 * If we don't have pte special, then we have to use the pfn_valid()
1754 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1755 * refcount the page if pfn_valid is true (hence insert_page rather
1756 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1757 * without pte special, it would there be refcounted as a normal page.
1759 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1762 page = pfn_to_page(pfn);
1763 return insert_page(vma, addr, page, vma->vm_page_prot);
1765 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1767 EXPORT_SYMBOL(vm_insert_mixed);
1770 * maps a range of physical memory into the requested pages. the old
1771 * mappings are removed. any references to nonexistent pages results
1772 * in null mappings (currently treated as "copy-on-access")
1774 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1775 unsigned long addr, unsigned long end,
1776 unsigned long pfn, pgprot_t prot)
1781 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1784 arch_enter_lazy_mmu_mode();
1786 BUG_ON(!pte_none(*pte));
1787 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
1789 } while (pte++, addr += PAGE_SIZE, addr != end);
1790 arch_leave_lazy_mmu_mode();
1791 pte_unmap_unlock(pte - 1, ptl);
1795 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1796 unsigned long addr, unsigned long end,
1797 unsigned long pfn, pgprot_t prot)
1802 pfn -= addr >> PAGE_SHIFT;
1803 pmd = pmd_alloc(mm, pud, addr);
1807 next = pmd_addr_end(addr, end);
1808 if (remap_pte_range(mm, pmd, addr, next,
1809 pfn + (addr >> PAGE_SHIFT), prot))
1811 } while (pmd++, addr = next, addr != end);
1815 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1816 unsigned long addr, unsigned long end,
1817 unsigned long pfn, pgprot_t prot)
1822 pfn -= addr >> PAGE_SHIFT;
1823 pud = pud_alloc(mm, pgd, addr);
1827 next = pud_addr_end(addr, end);
1828 if (remap_pmd_range(mm, pud, addr, next,
1829 pfn + (addr >> PAGE_SHIFT), prot))
1831 } while (pud++, addr = next, addr != end);
1836 * remap_pfn_range - remap kernel memory to userspace
1837 * @vma: user vma to map to
1838 * @addr: target user address to start at
1839 * @pfn: physical address of kernel memory
1840 * @size: size of map area
1841 * @prot: page protection flags for this mapping
1843 * Note: this is only safe if the mm semaphore is held when called.
1845 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1846 unsigned long pfn, unsigned long size, pgprot_t prot)
1850 unsigned long end = addr + PAGE_ALIGN(size);
1851 struct mm_struct *mm = vma->vm_mm;
1855 * Physically remapped pages are special. Tell the
1856 * rest of the world about it:
1857 * VM_IO tells people not to look at these pages
1858 * (accesses can have side effects).
1859 * VM_RESERVED is specified all over the place, because
1860 * in 2.4 it kept swapout's vma scan off this vma; but
1861 * in 2.6 the LRU scan won't even find its pages, so this
1862 * flag means no more than count its pages in reserved_vm,
1863 * and omit it from core dump, even when VM_IO turned off.
1864 * VM_PFNMAP tells the core MM that the base pages are just
1865 * raw PFN mappings, and do not have a "struct page" associated
1868 * There's a horrible special case to handle copy-on-write
1869 * behaviour that some programs depend on. We mark the "original"
1870 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1872 if (addr == vma->vm_start && end == vma->vm_end) {
1873 vma->vm_pgoff = pfn;
1874 vma->vm_flags |= VM_PFN_AT_MMAP;
1875 } else if (is_cow_mapping(vma->vm_flags))
1878 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
1880 err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
1883 * To indicate that track_pfn related cleanup is not
1884 * needed from higher level routine calling unmap_vmas
1886 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
1887 vma->vm_flags &= ~VM_PFN_AT_MMAP;
1891 BUG_ON(addr >= end);
1892 pfn -= addr >> PAGE_SHIFT;
1893 pgd = pgd_offset(mm, addr);
1894 flush_cache_range(vma, addr, end);
1896 next = pgd_addr_end(addr, end);
1897 err = remap_pud_range(mm, pgd, addr, next,
1898 pfn + (addr >> PAGE_SHIFT), prot);
1901 } while (pgd++, addr = next, addr != end);
1904 untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
1908 EXPORT_SYMBOL(remap_pfn_range);
1910 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1911 unsigned long addr, unsigned long end,
1912 pte_fn_t fn, void *data)
1917 spinlock_t *uninitialized_var(ptl);
1919 pte = (mm == &init_mm) ?
1920 pte_alloc_kernel(pmd, addr) :
1921 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1925 BUG_ON(pmd_huge(*pmd));
1927 arch_enter_lazy_mmu_mode();
1929 token = pmd_pgtable(*pmd);
1932 err = fn(pte++, token, addr, data);
1935 } while (addr += PAGE_SIZE, addr != end);
1937 arch_leave_lazy_mmu_mode();
1940 pte_unmap_unlock(pte-1, ptl);
1944 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1945 unsigned long addr, unsigned long end,
1946 pte_fn_t fn, void *data)
1952 BUG_ON(pud_huge(*pud));
1954 pmd = pmd_alloc(mm, pud, addr);
1958 next = pmd_addr_end(addr, end);
1959 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1962 } while (pmd++, addr = next, addr != end);
1966 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1967 unsigned long addr, unsigned long end,
1968 pte_fn_t fn, void *data)
1974 pud = pud_alloc(mm, pgd, addr);
1978 next = pud_addr_end(addr, end);
1979 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1982 } while (pud++, addr = next, addr != end);
1987 * Scan a region of virtual memory, filling in page tables as necessary
1988 * and calling a provided function on each leaf page table.
1990 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1991 unsigned long size, pte_fn_t fn, void *data)
1995 unsigned long start = addr, end = addr + size;
1998 BUG_ON(addr >= end);
1999 mmu_notifier_invalidate_range_start(mm, start, end);
2000 pgd = pgd_offset(mm, addr);
2002 next = pgd_addr_end(addr, end);
2003 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2006 } while (pgd++, addr = next, addr != end);
2007 mmu_notifier_invalidate_range_end(mm, start, end);
2010 EXPORT_SYMBOL_GPL(apply_to_page_range);
2013 * handle_pte_fault chooses page fault handler according to an entry
2014 * which was read non-atomically. Before making any commitment, on
2015 * those architectures or configurations (e.g. i386 with PAE) which
2016 * might give a mix of unmatched parts, do_swap_page and do_file_page
2017 * must check under lock before unmapping the pte and proceeding
2018 * (but do_wp_page is only called after already making such a check;
2019 * and do_anonymous_page and do_no_page can safely check later on).
2021 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2022 pte_t *page_table, pte_t orig_pte)
2025 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2026 if (sizeof(pte_t) > sizeof(unsigned long)) {
2027 spinlock_t *ptl = pte_lockptr(mm, pmd);
2029 same = pte_same(*page_table, orig_pte);
2033 pte_unmap(page_table);
2038 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
2039 * servicing faults for write access. In the normal case, do always want
2040 * pte_mkwrite. But get_user_pages can cause write faults for mappings
2041 * that do not have writing enabled, when used by access_process_vm.
2043 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
2045 if (likely(vma->vm_flags & VM_WRITE))
2046 pte = pte_mkwrite(pte);
2050 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2053 * If the source page was a PFN mapping, we don't have
2054 * a "struct page" for it. We do a best-effort copy by
2055 * just copying from the original user address. If that
2056 * fails, we just zero-fill it. Live with it.
2058 if (unlikely(!src)) {
2059 void *kaddr = kmap_atomic(dst, KM_USER0);
2060 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2063 * This really shouldn't fail, because the page is there
2064 * in the page tables. But it might just be unreadable,
2065 * in which case we just give up and fill the result with
2068 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2069 memset(kaddr, 0, PAGE_SIZE);
2070 kunmap_atomic(kaddr, KM_USER0);
2071 flush_dcache_page(dst);
2073 copy_user_highpage(dst, src, va, vma);
2077 * This routine handles present pages, when users try to write
2078 * to a shared page. It is done by copying the page to a new address
2079 * and decrementing the shared-page counter for the old page.
2081 * Note that this routine assumes that the protection checks have been
2082 * done by the caller (the low-level page fault routine in most cases).
2083 * Thus we can safely just mark it writable once we've done any necessary
2086 * We also mark the page dirty at this point even though the page will
2087 * change only once the write actually happens. This avoids a few races,
2088 * and potentially makes it more efficient.
2090 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2091 * but allow concurrent faults), with pte both mapped and locked.
2092 * We return with mmap_sem still held, but pte unmapped and unlocked.
2094 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2095 unsigned long address, pte_t *page_table, pmd_t *pmd,
2096 spinlock_t *ptl, pte_t orig_pte)
2098 struct page *old_page, *new_page;
2100 int reuse = 0, ret = 0;
2101 int page_mkwrite = 0;
2102 struct page *dirty_page = NULL;
2104 old_page = vm_normal_page(vma, address, orig_pte);
2107 * VM_MIXEDMAP !pfn_valid() case
2109 * We should not cow pages in a shared writeable mapping.
2110 * Just mark the pages writable as we can't do any dirty
2111 * accounting on raw pfn maps.
2113 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2114 (VM_WRITE|VM_SHARED))
2120 * Take out anonymous pages first, anonymous shared vmas are
2121 * not dirty accountable.
2123 if (PageAnon(old_page) && !PageKsm(old_page)) {
2124 if (!trylock_page(old_page)) {
2125 page_cache_get(old_page);
2126 pte_unmap_unlock(page_table, ptl);
2127 lock_page(old_page);
2128 page_table = pte_offset_map_lock(mm, pmd, address,
2130 if (!pte_same(*page_table, orig_pte)) {
2131 unlock_page(old_page);
2132 page_cache_release(old_page);
2135 page_cache_release(old_page);
2137 reuse = reuse_swap_page(old_page);
2140 * The page is all ours. Move it to our anon_vma so
2141 * the rmap code will not search our parent or siblings.
2142 * Protected against the rmap code by the page lock.
2144 page_move_anon_rmap(old_page, vma, address);
2145 unlock_page(old_page);
2146 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2147 (VM_WRITE|VM_SHARED))) {
2149 * Only catch write-faults on shared writable pages,
2150 * read-only shared pages can get COWed by
2151 * get_user_pages(.write=1, .force=1).
2153 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2154 struct vm_fault vmf;
2157 vmf.virtual_address = (void __user *)(address &
2159 vmf.pgoff = old_page->index;
2160 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2161 vmf.page = old_page;
2164 * Notify the address space that the page is about to
2165 * become writable so that it can prohibit this or wait
2166 * for the page to get into an appropriate state.
2168 * We do this without the lock held, so that it can
2169 * sleep if it needs to.
2171 page_cache_get(old_page);
2172 pte_unmap_unlock(page_table, ptl);
2174 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2176 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2178 goto unwritable_page;
2180 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2181 lock_page(old_page);
2182 if (!old_page->mapping) {
2183 ret = 0; /* retry the fault */
2184 unlock_page(old_page);
2185 goto unwritable_page;
2188 VM_BUG_ON(!PageLocked(old_page));
2191 * Since we dropped the lock we need to revalidate
2192 * the PTE as someone else may have changed it. If
2193 * they did, we just return, as we can count on the
2194 * MMU to tell us if they didn't also make it writable.
2196 page_table = pte_offset_map_lock(mm, pmd, address,
2198 if (!pte_same(*page_table, orig_pte)) {
2199 unlock_page(old_page);
2200 page_cache_release(old_page);
2206 dirty_page = old_page;
2207 get_page(dirty_page);
2213 flush_cache_page(vma, address, pte_pfn(orig_pte));
2214 entry = pte_mkyoung(orig_pte);
2215 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2216 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2217 update_mmu_cache(vma, address, page_table);
2218 ret |= VM_FAULT_WRITE;
2223 * Ok, we need to copy. Oh, well..
2225 page_cache_get(old_page);
2227 pte_unmap_unlock(page_table, ptl);
2229 if (unlikely(anon_vma_prepare(vma)))
2232 if (is_zero_pfn(pte_pfn(orig_pte))) {
2233 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2237 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2240 cow_user_page(new_page, old_page, address, vma);
2242 __SetPageUptodate(new_page);
2245 * Don't let another task, with possibly unlocked vma,
2246 * keep the mlocked page.
2248 if ((vma->vm_flags & VM_LOCKED) && old_page) {
2249 lock_page(old_page); /* for LRU manipulation */
2250 clear_page_mlock(old_page);
2251 unlock_page(old_page);
2254 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2258 * Re-check the pte - we dropped the lock
2260 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2261 if (likely(pte_same(*page_table, orig_pte))) {
2263 if (!PageAnon(old_page)) {
2264 dec_mm_counter_fast(mm, MM_FILEPAGES);
2265 inc_mm_counter_fast(mm, MM_ANONPAGES);
2268 inc_mm_counter_fast(mm, MM_ANONPAGES);
2269 flush_cache_page(vma, address, pte_pfn(orig_pte));
2270 entry = mk_pte(new_page, vma->vm_page_prot);
2271 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2273 * Clear the pte entry and flush it first, before updating the
2274 * pte with the new entry. This will avoid a race condition
2275 * seen in the presence of one thread doing SMC and another
2278 ptep_clear_flush(vma, address, page_table);
2279 page_add_new_anon_rmap(new_page, vma, address);
2281 * We call the notify macro here because, when using secondary
2282 * mmu page tables (such as kvm shadow page tables), we want the
2283 * new page to be mapped directly into the secondary page table.
2285 set_pte_at_notify(mm, address, page_table, entry);
2286 update_mmu_cache(vma, address, page_table);
2289 * Only after switching the pte to the new page may
2290 * we remove the mapcount here. Otherwise another
2291 * process may come and find the rmap count decremented
2292 * before the pte is switched to the new page, and
2293 * "reuse" the old page writing into it while our pte
2294 * here still points into it and can be read by other
2297 * The critical issue is to order this
2298 * page_remove_rmap with the ptp_clear_flush above.
2299 * Those stores are ordered by (if nothing else,)
2300 * the barrier present in the atomic_add_negative
2301 * in page_remove_rmap.
2303 * Then the TLB flush in ptep_clear_flush ensures that
2304 * no process can access the old page before the
2305 * decremented mapcount is visible. And the old page
2306 * cannot be reused until after the decremented
2307 * mapcount is visible. So transitively, TLBs to
2308 * old page will be flushed before it can be reused.
2310 page_remove_rmap(old_page);
2313 /* Free the old page.. */
2314 new_page = old_page;
2315 ret |= VM_FAULT_WRITE;
2317 mem_cgroup_uncharge_page(new_page);
2320 page_cache_release(new_page);
2322 page_cache_release(old_page);
2324 pte_unmap_unlock(page_table, ptl);
2327 * Yes, Virginia, this is actually required to prevent a race
2328 * with clear_page_dirty_for_io() from clearing the page dirty
2329 * bit after it clear all dirty ptes, but before a racing
2330 * do_wp_page installs a dirty pte.
2332 * do_no_page is protected similarly.
2334 if (!page_mkwrite) {
2335 wait_on_page_locked(dirty_page);
2336 set_page_dirty_balance(dirty_page, page_mkwrite);
2338 put_page(dirty_page);
2340 struct address_space *mapping = dirty_page->mapping;
2342 set_page_dirty(dirty_page);
2343 unlock_page(dirty_page);
2344 page_cache_release(dirty_page);
2347 * Some device drivers do not set page.mapping
2348 * but still dirty their pages
2350 balance_dirty_pages_ratelimited(mapping);
2354 /* file_update_time outside page_lock */
2356 file_update_time(vma->vm_file);
2360 page_cache_release(new_page);
2364 unlock_page(old_page);
2365 page_cache_release(old_page);
2367 page_cache_release(old_page);
2369 return VM_FAULT_OOM;
2372 page_cache_release(old_page);
2377 * Helper functions for unmap_mapping_range().
2379 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2381 * We have to restart searching the prio_tree whenever we drop the lock,
2382 * since the iterator is only valid while the lock is held, and anyway
2383 * a later vma might be split and reinserted earlier while lock dropped.
2385 * The list of nonlinear vmas could be handled more efficiently, using
2386 * a placeholder, but handle it in the same way until a need is shown.
2387 * It is important to search the prio_tree before nonlinear list: a vma
2388 * may become nonlinear and be shifted from prio_tree to nonlinear list
2389 * while the lock is dropped; but never shifted from list to prio_tree.
2391 * In order to make forward progress despite restarting the search,
2392 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2393 * quickly skip it next time around. Since the prio_tree search only
2394 * shows us those vmas affected by unmapping the range in question, we
2395 * can't efficiently keep all vmas in step with mapping->truncate_count:
2396 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2397 * mapping->truncate_count and vma->vm_truncate_count are protected by
2400 * In order to make forward progress despite repeatedly restarting some
2401 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2402 * and restart from that address when we reach that vma again. It might
2403 * have been split or merged, shrunk or extended, but never shifted: so
2404 * restart_addr remains valid so long as it remains in the vma's range.
2405 * unmap_mapping_range forces truncate_count to leap over page-aligned
2406 * values so we can save vma's restart_addr in its truncate_count field.
2408 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2410 static void reset_vma_truncate_counts(struct address_space *mapping)
2412 struct vm_area_struct *vma;
2413 struct prio_tree_iter iter;
2415 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2416 vma->vm_truncate_count = 0;
2417 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2418 vma->vm_truncate_count = 0;
2421 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2422 unsigned long start_addr, unsigned long end_addr,
2423 struct zap_details *details)
2425 unsigned long restart_addr;
2429 * files that support invalidating or truncating portions of the
2430 * file from under mmaped areas must have their ->fault function
2431 * return a locked page (and set VM_FAULT_LOCKED in the return).
2432 * This provides synchronisation against concurrent unmapping here.
2436 restart_addr = vma->vm_truncate_count;
2437 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2438 start_addr = restart_addr;
2439 if (start_addr >= end_addr) {
2440 /* Top of vma has been split off since last time */
2441 vma->vm_truncate_count = details->truncate_count;
2446 restart_addr = zap_page_range(vma, start_addr,
2447 end_addr - start_addr, details);
2448 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
2450 if (restart_addr >= end_addr) {
2451 /* We have now completed this vma: mark it so */
2452 vma->vm_truncate_count = details->truncate_count;
2456 /* Note restart_addr in vma's truncate_count field */
2457 vma->vm_truncate_count = restart_addr;
2462 spin_unlock(details->i_mmap_lock);
2464 spin_lock(details->i_mmap_lock);
2468 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2469 struct zap_details *details)
2471 struct vm_area_struct *vma;
2472 struct prio_tree_iter iter;
2473 pgoff_t vba, vea, zba, zea;
2476 vma_prio_tree_foreach(vma, &iter, root,
2477 details->first_index, details->last_index) {
2478 /* Skip quickly over those we have already dealt with */
2479 if (vma->vm_truncate_count == details->truncate_count)
2482 vba = vma->vm_pgoff;
2483 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2484 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2485 zba = details->first_index;
2488 zea = details->last_index;
2492 if (unmap_mapping_range_vma(vma,
2493 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2494 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2500 static inline void unmap_mapping_range_list(struct list_head *head,
2501 struct zap_details *details)
2503 struct vm_area_struct *vma;
2506 * In nonlinear VMAs there is no correspondence between virtual address
2507 * offset and file offset. So we must perform an exhaustive search
2508 * across *all* the pages in each nonlinear VMA, not just the pages
2509 * whose virtual address lies outside the file truncation point.
2512 list_for_each_entry(vma, head, shared.vm_set.list) {
2513 /* Skip quickly over those we have already dealt with */
2514 if (vma->vm_truncate_count == details->truncate_count)
2516 details->nonlinear_vma = vma;
2517 if (unmap_mapping_range_vma(vma, vma->vm_start,
2518 vma->vm_end, details) < 0)
2524 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2525 * @mapping: the address space containing mmaps to be unmapped.
2526 * @holebegin: byte in first page to unmap, relative to the start of
2527 * the underlying file. This will be rounded down to a PAGE_SIZE
2528 * boundary. Note that this is different from truncate_pagecache(), which
2529 * must keep the partial page. In contrast, we must get rid of
2531 * @holelen: size of prospective hole in bytes. This will be rounded
2532 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2534 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2535 * but 0 when invalidating pagecache, don't throw away private data.
2537 void unmap_mapping_range(struct address_space *mapping,
2538 loff_t const holebegin, loff_t const holelen, int even_cows)
2540 struct zap_details details;
2541 pgoff_t hba = holebegin >> PAGE_SHIFT;
2542 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2544 /* Check for overflow. */
2545 if (sizeof(holelen) > sizeof(hlen)) {
2547 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2548 if (holeend & ~(long long)ULONG_MAX)
2549 hlen = ULONG_MAX - hba + 1;
2552 details.check_mapping = even_cows? NULL: mapping;
2553 details.nonlinear_vma = NULL;
2554 details.first_index = hba;
2555 details.last_index = hba + hlen - 1;
2556 if (details.last_index < details.first_index)
2557 details.last_index = ULONG_MAX;
2558 details.i_mmap_lock = &mapping->i_mmap_lock;
2560 spin_lock(&mapping->i_mmap_lock);
2562 /* Protect against endless unmapping loops */
2563 mapping->truncate_count++;
2564 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2565 if (mapping->truncate_count == 0)
2566 reset_vma_truncate_counts(mapping);
2567 mapping->truncate_count++;
2569 details.truncate_count = mapping->truncate_count;
2571 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2572 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2573 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2574 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2575 spin_unlock(&mapping->i_mmap_lock);
2577 EXPORT_SYMBOL(unmap_mapping_range);
2579 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2581 struct address_space *mapping = inode->i_mapping;
2584 * If the underlying filesystem is not going to provide
2585 * a way to truncate a range of blocks (punch a hole) -
2586 * we should return failure right now.
2588 if (!inode->i_op->truncate_range)
2591 mutex_lock(&inode->i_mutex);
2592 down_write(&inode->i_alloc_sem);
2593 unmap_mapping_range(mapping, offset, (end - offset), 1);
2594 truncate_inode_pages_range(mapping, offset, end);
2595 unmap_mapping_range(mapping, offset, (end - offset), 1);
2596 inode->i_op->truncate_range(inode, offset, end);
2597 up_write(&inode->i_alloc_sem);
2598 mutex_unlock(&inode->i_mutex);
2604 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2605 * but allow concurrent faults), and pte mapped but not yet locked.
2606 * We return with mmap_sem still held, but pte unmapped and unlocked.
2608 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2609 unsigned long address, pte_t *page_table, pmd_t *pmd,
2610 unsigned int flags, pte_t orig_pte)
2616 struct mem_cgroup *ptr = NULL;
2619 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2622 entry = pte_to_swp_entry(orig_pte);
2623 if (unlikely(non_swap_entry(entry))) {
2624 if (is_migration_entry(entry)) {
2625 migration_entry_wait(mm, pmd, address);
2626 } else if (is_hwpoison_entry(entry)) {
2627 ret = VM_FAULT_HWPOISON;
2629 print_bad_pte(vma, address, orig_pte, NULL);
2630 ret = VM_FAULT_SIGBUS;
2634 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2635 page = lookup_swap_cache(entry);
2637 grab_swap_token(mm); /* Contend for token _before_ read-in */
2638 page = swapin_readahead(entry,
2639 GFP_HIGHUSER_MOVABLE, vma, address);
2642 * Back out if somebody else faulted in this pte
2643 * while we released the pte lock.
2645 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2646 if (likely(pte_same(*page_table, orig_pte)))
2648 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2652 /* Had to read the page from swap area: Major fault */
2653 ret = VM_FAULT_MAJOR;
2654 count_vm_event(PGMAJFAULT);
2655 } else if (PageHWPoison(page)) {
2657 * hwpoisoned dirty swapcache pages are kept for killing
2658 * owner processes (which may be unknown at hwpoison time)
2660 ret = VM_FAULT_HWPOISON;
2661 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2666 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2668 page = ksm_might_need_to_copy(page, vma, address);
2674 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
2680 * Back out if somebody else already faulted in this pte.
2682 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2683 if (unlikely(!pte_same(*page_table, orig_pte)))
2686 if (unlikely(!PageUptodate(page))) {
2687 ret = VM_FAULT_SIGBUS;
2692 * The page isn't present yet, go ahead with the fault.
2694 * Be careful about the sequence of operations here.
2695 * To get its accounting right, reuse_swap_page() must be called
2696 * while the page is counted on swap but not yet in mapcount i.e.
2697 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2698 * must be called after the swap_free(), or it will never succeed.
2699 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2700 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2701 * in page->private. In this case, a record in swap_cgroup is silently
2702 * discarded at swap_free().
2705 inc_mm_counter_fast(mm, MM_ANONPAGES);
2706 dec_mm_counter_fast(mm, MM_SWAPENTS);
2707 pte = mk_pte(page, vma->vm_page_prot);
2708 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
2709 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2710 flags &= ~FAULT_FLAG_WRITE;
2712 flush_icache_page(vma, page);
2713 set_pte_at(mm, address, page_table, pte);
2714 page_add_anon_rmap(page, vma, address);
2715 /* It's better to call commit-charge after rmap is established */
2716 mem_cgroup_commit_charge_swapin(page, ptr);
2719 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
2720 try_to_free_swap(page);
2723 if (flags & FAULT_FLAG_WRITE) {
2724 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2725 if (ret & VM_FAULT_ERROR)
2726 ret &= VM_FAULT_ERROR;
2730 /* No need to invalidate - it was non-present before */
2731 update_mmu_cache(vma, address, page_table);
2733 pte_unmap_unlock(page_table, ptl);
2737 mem_cgroup_cancel_charge_swapin(ptr);
2738 pte_unmap_unlock(page_table, ptl);
2742 page_cache_release(page);
2747 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2748 * but allow concurrent faults), and pte mapped but not yet locked.
2749 * We return with mmap_sem still held, but pte unmapped and unlocked.
2751 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2752 unsigned long address, pte_t *page_table, pmd_t *pmd,
2759 if (!(flags & FAULT_FLAG_WRITE)) {
2760 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2761 vma->vm_page_prot));
2762 ptl = pte_lockptr(mm, pmd);
2764 if (!pte_none(*page_table))
2769 /* Allocate our own private page. */
2770 pte_unmap(page_table);
2772 if (unlikely(anon_vma_prepare(vma)))
2774 page = alloc_zeroed_user_highpage_movable(vma, address);
2777 __SetPageUptodate(page);
2779 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
2782 entry = mk_pte(page, vma->vm_page_prot);
2783 if (vma->vm_flags & VM_WRITE)
2784 entry = pte_mkwrite(pte_mkdirty(entry));
2786 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2787 if (!pte_none(*page_table))
2790 inc_mm_counter_fast(mm, MM_ANONPAGES);
2791 page_add_new_anon_rmap(page, vma, address);
2793 set_pte_at(mm, address, page_table, entry);
2795 /* No need to invalidate - it was non-present before */
2796 update_mmu_cache(vma, address, page_table);
2798 pte_unmap_unlock(page_table, ptl);
2801 mem_cgroup_uncharge_page(page);
2802 page_cache_release(page);
2805 page_cache_release(page);
2807 return VM_FAULT_OOM;
2811 * __do_fault() tries to create a new page mapping. It aggressively
2812 * tries to share with existing pages, but makes a separate copy if
2813 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2814 * the next page fault.
2816 * As this is called only for pages that do not currently exist, we
2817 * do not need to flush old virtual caches or the TLB.
2819 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2820 * but allow concurrent faults), and pte neither mapped nor locked.
2821 * We return with mmap_sem still held, but pte unmapped and unlocked.
2823 static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2824 unsigned long address, pmd_t *pmd,
2825 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2833 struct page *dirty_page = NULL;
2834 struct vm_fault vmf;
2836 int page_mkwrite = 0;
2838 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2843 ret = vma->vm_ops->fault(vma, &vmf);
2844 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2847 if (unlikely(PageHWPoison(vmf.page))) {
2848 if (ret & VM_FAULT_LOCKED)
2849 unlock_page(vmf.page);
2850 return VM_FAULT_HWPOISON;
2854 * For consistency in subsequent calls, make the faulted page always
2857 if (unlikely(!(ret & VM_FAULT_LOCKED)))
2858 lock_page(vmf.page);
2860 VM_BUG_ON(!PageLocked(vmf.page));
2863 * Should we do an early C-O-W break?
2866 if (flags & FAULT_FLAG_WRITE) {
2867 if (!(vma->vm_flags & VM_SHARED)) {
2869 if (unlikely(anon_vma_prepare(vma))) {
2873 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2879 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
2881 page_cache_release(page);
2886 * Don't let another task, with possibly unlocked vma,
2887 * keep the mlocked page.
2889 if (vma->vm_flags & VM_LOCKED)
2890 clear_page_mlock(vmf.page);
2891 copy_user_highpage(page, vmf.page, address, vma);
2892 __SetPageUptodate(page);
2895 * If the page will be shareable, see if the backing
2896 * address space wants to know that the page is about
2897 * to become writable
2899 if (vma->vm_ops->page_mkwrite) {
2903 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2904 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2906 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2908 goto unwritable_page;
2910 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2912 if (!page->mapping) {
2913 ret = 0; /* retry the fault */
2915 goto unwritable_page;
2918 VM_BUG_ON(!PageLocked(page));
2925 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2928 * This silly early PAGE_DIRTY setting removes a race
2929 * due to the bad i386 page protection. But it's valid
2930 * for other architectures too.
2932 * Note that if FAULT_FLAG_WRITE is set, we either now have
2933 * an exclusive copy of the page, or this is a shared mapping,
2934 * so we can make it writable and dirty to avoid having to
2935 * handle that later.
2937 /* Only go through if we didn't race with anybody else... */
2938 if (likely(pte_same(*page_table, orig_pte))) {
2939 flush_icache_page(vma, page);
2940 entry = mk_pte(page, vma->vm_page_prot);
2941 if (flags & FAULT_FLAG_WRITE)
2942 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2944 inc_mm_counter_fast(mm, MM_ANONPAGES);
2945 page_add_new_anon_rmap(page, vma, address);
2947 inc_mm_counter_fast(mm, MM_FILEPAGES);
2948 page_add_file_rmap(page);
2949 if (flags & FAULT_FLAG_WRITE) {
2951 get_page(dirty_page);
2954 set_pte_at(mm, address, page_table, entry);
2956 /* no need to invalidate: a not-present page won't be cached */
2957 update_mmu_cache(vma, address, page_table);
2960 mem_cgroup_uncharge_page(page);
2962 page_cache_release(page);
2964 anon = 1; /* no anon but release faulted_page */
2967 pte_unmap_unlock(page_table, ptl);
2971 struct address_space *mapping = page->mapping;
2973 if (set_page_dirty(dirty_page))
2975 unlock_page(dirty_page);
2976 put_page(dirty_page);
2977 if (page_mkwrite && mapping) {
2979 * Some device drivers do not set page.mapping but still
2982 balance_dirty_pages_ratelimited(mapping);
2985 /* file_update_time outside page_lock */
2987 file_update_time(vma->vm_file);
2989 unlock_page(vmf.page);
2991 page_cache_release(vmf.page);
2997 page_cache_release(page);
3001 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3002 unsigned long address, pte_t *page_table, pmd_t *pmd,
3003 unsigned int flags, pte_t orig_pte)
3005 pgoff_t pgoff = (((address & PAGE_MASK)
3006 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3008 pte_unmap(page_table);
3009 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3013 * Fault of a previously existing named mapping. Repopulate the pte
3014 * from the encoded file_pte if possible. This enables swappable
3017 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3018 * but allow concurrent faults), and pte mapped but not yet locked.
3019 * We return with mmap_sem still held, but pte unmapped and unlocked.
3021 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3022 unsigned long address, pte_t *page_table, pmd_t *pmd,
3023 unsigned int flags, pte_t orig_pte)
3027 flags |= FAULT_FLAG_NONLINEAR;
3029 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3032 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3034 * Page table corrupted: show pte and kill process.
3036 print_bad_pte(vma, address, orig_pte, NULL);
3037 return VM_FAULT_SIGBUS;
3040 pgoff = pte_to_pgoff(orig_pte);
3041 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3045 * These routines also need to handle stuff like marking pages dirty
3046 * and/or accessed for architectures that don't do it in hardware (most
3047 * RISC architectures). The early dirtying is also good on the i386.
3049 * There is also a hook called "update_mmu_cache()" that architectures
3050 * with external mmu caches can use to update those (ie the Sparc or
3051 * PowerPC hashed page tables that act as extended TLBs).
3053 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3054 * but allow concurrent faults), and pte mapped but not yet locked.
3055 * We return with mmap_sem still held, but pte unmapped and unlocked.
3057 static inline int handle_pte_fault(struct mm_struct *mm,
3058 struct vm_area_struct *vma, unsigned long address,
3059 pte_t *pte, pmd_t *pmd, unsigned int flags)
3065 if (!pte_present(entry)) {
3066 if (pte_none(entry)) {
3068 if (likely(vma->vm_ops->fault))
3069 return do_linear_fault(mm, vma, address,
3070 pte, pmd, flags, entry);
3072 return do_anonymous_page(mm, vma, address,
3075 if (pte_file(entry))
3076 return do_nonlinear_fault(mm, vma, address,
3077 pte, pmd, flags, entry);
3078 return do_swap_page(mm, vma, address,
3079 pte, pmd, flags, entry);
3082 ptl = pte_lockptr(mm, pmd);
3084 if (unlikely(!pte_same(*pte, entry)))
3086 if (flags & FAULT_FLAG_WRITE) {
3087 if (!pte_write(entry))
3088 return do_wp_page(mm, vma, address,
3089 pte, pmd, ptl, entry);
3090 entry = pte_mkdirty(entry);
3092 entry = pte_mkyoung(entry);
3093 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3094 update_mmu_cache(vma, address, pte);
3097 * This is needed only for protection faults but the arch code
3098 * is not yet telling us if this is a protection fault or not.
3099 * This still avoids useless tlb flushes for .text page faults
3102 if (flags & FAULT_FLAG_WRITE)
3103 flush_tlb_page(vma, address);
3106 pte_unmap_unlock(pte, ptl);
3111 * By the time we get here, we already hold the mm semaphore
3113 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3114 unsigned long address, unsigned int flags)
3121 __set_current_state(TASK_RUNNING);
3123 count_vm_event(PGFAULT);
3125 /* do counter updates before entering really critical section. */
3126 check_sync_rss_stat(current);
3128 if (unlikely(is_vm_hugetlb_page(vma)))
3129 return hugetlb_fault(mm, vma, address, flags);
3131 pgd = pgd_offset(mm, address);
3132 pud = pud_alloc(mm, pgd, address);
3134 return VM_FAULT_OOM;
3135 pmd = pmd_alloc(mm, pud, address);
3137 return VM_FAULT_OOM;
3138 pte = pte_alloc_map(mm, pmd, address);
3140 return VM_FAULT_OOM;
3142 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3145 #ifndef __PAGETABLE_PUD_FOLDED
3147 * Allocate page upper directory.
3148 * We've already handled the fast-path in-line.
3150 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3152 pud_t *new = pud_alloc_one(mm, address);
3156 smp_wmb(); /* See comment in __pte_alloc */
3158 spin_lock(&mm->page_table_lock);
3159 if (pgd_present(*pgd)) /* Another has populated it */
3162 pgd_populate(mm, pgd, new);
3163 spin_unlock(&mm->page_table_lock);
3166 #endif /* __PAGETABLE_PUD_FOLDED */
3168 #ifndef __PAGETABLE_PMD_FOLDED
3170 * Allocate page middle directory.
3171 * We've already handled the fast-path in-line.
3173 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3175 pmd_t *new = pmd_alloc_one(mm, address);
3179 smp_wmb(); /* See comment in __pte_alloc */
3181 spin_lock(&mm->page_table_lock);
3182 #ifndef __ARCH_HAS_4LEVEL_HACK
3183 if (pud_present(*pud)) /* Another has populated it */
3186 pud_populate(mm, pud, new);
3188 if (pgd_present(*pud)) /* Another has populated it */
3191 pgd_populate(mm, pud, new);
3192 #endif /* __ARCH_HAS_4LEVEL_HACK */
3193 spin_unlock(&mm->page_table_lock);
3196 #endif /* __PAGETABLE_PMD_FOLDED */
3198 int make_pages_present(unsigned long addr, unsigned long end)
3200 int ret, len, write;
3201 struct vm_area_struct * vma;
3203 vma = find_vma(current->mm, addr);
3206 write = (vma->vm_flags & VM_WRITE) != 0;
3207 BUG_ON(addr >= end);
3208 BUG_ON(end > vma->vm_end);
3209 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
3210 ret = get_user_pages(current, current->mm, addr,
3211 len, write, 0, NULL, NULL);
3214 return ret == len ? 0 : -EFAULT;
3217 #if !defined(__HAVE_ARCH_GATE_AREA)
3219 #if defined(AT_SYSINFO_EHDR)
3220 static struct vm_area_struct gate_vma;
3222 static int __init gate_vma_init(void)
3224 gate_vma.vm_mm = NULL;
3225 gate_vma.vm_start = FIXADDR_USER_START;
3226 gate_vma.vm_end = FIXADDR_USER_END;
3227 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3228 gate_vma.vm_page_prot = __P101;
3230 * Make sure the vDSO gets into every core dump.
3231 * Dumping its contents makes post-mortem fully interpretable later
3232 * without matching up the same kernel and hardware config to see
3233 * what PC values meant.
3235 gate_vma.vm_flags |= VM_ALWAYSDUMP;
3238 __initcall(gate_vma_init);
3241 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
3243 #ifdef AT_SYSINFO_EHDR
3250 int in_gate_area_no_task(unsigned long addr)
3252 #ifdef AT_SYSINFO_EHDR
3253 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3259 #endif /* __HAVE_ARCH_GATE_AREA */
3261 static int follow_pte(struct mm_struct *mm, unsigned long address,
3262 pte_t **ptepp, spinlock_t **ptlp)
3269 pgd = pgd_offset(mm, address);
3270 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3273 pud = pud_offset(pgd, address);
3274 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3277 pmd = pmd_offset(pud, address);
3278 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3281 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3285 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3288 if (!pte_present(*ptep))
3293 pte_unmap_unlock(ptep, *ptlp);
3299 * follow_pfn - look up PFN at a user virtual address
3300 * @vma: memory mapping
3301 * @address: user virtual address
3302 * @pfn: location to store found PFN
3304 * Only IO mappings and raw PFN mappings are allowed.
3306 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3308 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3315 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3318 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3321 *pfn = pte_pfn(*ptep);
3322 pte_unmap_unlock(ptep, ptl);
3325 EXPORT_SYMBOL(follow_pfn);
3327 #ifdef CONFIG_HAVE_IOREMAP_PROT
3328 int follow_phys(struct vm_area_struct *vma,
3329 unsigned long address, unsigned int flags,
3330 unsigned long *prot, resource_size_t *phys)
3336 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3339 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
3343 if ((flags & FOLL_WRITE) && !pte_write(pte))
3346 *prot = pgprot_val(pte_pgprot(pte));
3347 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
3351 pte_unmap_unlock(ptep, ptl);
3356 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3357 void *buf, int len, int write)
3359 resource_size_t phys_addr;
3360 unsigned long prot = 0;
3361 void __iomem *maddr;
3362 int offset = addr & (PAGE_SIZE-1);
3364 if (follow_phys(vma, addr, write, &prot, &phys_addr))
3367 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3369 memcpy_toio(maddr + offset, buf, len);
3371 memcpy_fromio(buf, maddr + offset, len);
3379 * Access another process' address space.
3380 * Source/target buffer must be kernel space,
3381 * Do not walk the page table directly, use get_user_pages
3383 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
3385 struct mm_struct *mm;
3386 struct vm_area_struct *vma;
3387 void *old_buf = buf;
3389 mm = get_task_mm(tsk);
3393 down_read(&mm->mmap_sem);
3394 /* ignore errors, just check how much was successfully transferred */
3396 int bytes, ret, offset;
3398 struct page *page = NULL;
3400 ret = get_user_pages(tsk, mm, addr, 1,
3401 write, 1, &page, &vma);
3404 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3405 * we can access using slightly different code.
3407 #ifdef CONFIG_HAVE_IOREMAP_PROT
3408 vma = find_vma(mm, addr);
3411 if (vma->vm_ops && vma->vm_ops->access)
3412 ret = vma->vm_ops->access(vma, addr, buf,
3420 offset = addr & (PAGE_SIZE-1);
3421 if (bytes > PAGE_SIZE-offset)
3422 bytes = PAGE_SIZE-offset;
3426 copy_to_user_page(vma, page, addr,
3427 maddr + offset, buf, bytes);
3428 set_page_dirty_lock(page);
3430 copy_from_user_page(vma, page, addr,
3431 buf, maddr + offset, bytes);
3434 page_cache_release(page);
3440 up_read(&mm->mmap_sem);
3443 return buf - old_buf;
3447 * Print the name of a VMA.
3449 void print_vma_addr(char *prefix, unsigned long ip)
3451 struct mm_struct *mm = current->mm;
3452 struct vm_area_struct *vma;
3455 * Do not print if we are in atomic
3456 * contexts (in exception stacks, etc.):
3458 if (preempt_count())
3461 down_read(&mm->mmap_sem);
3462 vma = find_vma(mm, ip);
3463 if (vma && vma->vm_file) {
3464 struct file *f = vma->vm_file;
3465 char *buf = (char *)__get_free_page(GFP_KERNEL);
3469 p = d_path(&f->f_path, buf, PAGE_SIZE);
3472 s = strrchr(p, '/');
3475 printk("%s%s[%lx+%lx]", prefix, p,
3477 vma->vm_end - vma->vm_start);
3478 free_page((unsigned long)buf);
3481 up_read(¤t->mm->mmap_sem);
3484 #ifdef CONFIG_PROVE_LOCKING
3485 void might_fault(void)
3488 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3489 * holding the mmap_sem, this is safe because kernel memory doesn't
3490 * get paged out, therefore we'll never actually fault, and the
3491 * below annotations will generate false positives.
3493 if (segment_eq(get_fs(), KERNEL_DS))
3498 * it would be nicer only to annotate paths which are not under
3499 * pagefault_disable, however that requires a larger audit and
3500 * providing helpers like get_user_atomic.
3502 if (!in_atomic() && current->mm)
3503 might_lock_read(¤t->mm->mmap_sem);
3505 EXPORT_SYMBOL(might_fault);