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>
59 #include <linux/gfp.h>
62 #include <asm/pgalloc.h>
63 #include <asm/uaccess.h>
65 #include <asm/tlbflush.h>
66 #include <asm/pgtable.h>
70 #ifndef CONFIG_NEED_MULTIPLE_NODES
71 /* use the per-pgdat data instead for discontigmem - mbligh */
72 unsigned long max_mapnr;
75 EXPORT_SYMBOL(max_mapnr);
76 EXPORT_SYMBOL(mem_map);
79 unsigned long num_physpages;
81 * A number of key systems in x86 including ioremap() rely on the assumption
82 * that high_memory defines the upper bound on direct map memory, then end
83 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
84 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
89 EXPORT_SYMBOL(num_physpages);
90 EXPORT_SYMBOL(high_memory);
93 * Randomize the address space (stacks, mmaps, brk, etc.).
95 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
96 * as ancient (libc5 based) binaries can segfault. )
98 int randomize_va_space __read_mostly =
99 #ifdef CONFIG_COMPAT_BRK
105 static int __init disable_randmaps(char *s)
107 randomize_va_space = 0;
110 __setup("norandmaps", disable_randmaps);
112 unsigned long zero_pfn __read_mostly;
113 unsigned long highest_memmap_pfn __read_mostly;
116 * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
118 static int __init init_zero_pfn(void)
120 zero_pfn = page_to_pfn(ZERO_PAGE(0));
123 core_initcall(init_zero_pfn);
126 #if defined(SPLIT_RSS_COUNTING)
128 static void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm)
132 for (i = 0; i < NR_MM_COUNTERS; i++) {
133 if (task->rss_stat.count[i]) {
134 add_mm_counter(mm, i, task->rss_stat.count[i]);
135 task->rss_stat.count[i] = 0;
138 task->rss_stat.events = 0;
141 static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
143 struct task_struct *task = current;
145 if (likely(task->mm == mm))
146 task->rss_stat.count[member] += val;
148 add_mm_counter(mm, member, val);
150 #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
151 #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
153 /* sync counter once per 64 page faults */
154 #define TASK_RSS_EVENTS_THRESH (64)
155 static void check_sync_rss_stat(struct task_struct *task)
157 if (unlikely(task != current))
159 if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
160 __sync_task_rss_stat(task, task->mm);
163 unsigned long get_mm_counter(struct mm_struct *mm, int member)
168 * Don't use task->mm here...for avoiding to use task_get_mm()..
169 * The caller must guarantee task->mm is not invalid.
171 val = atomic_long_read(&mm->rss_stat.count[member]);
173 * counter is updated in asynchronous manner and may go to minus.
174 * But it's never be expected number for users.
178 return (unsigned long)val;
181 void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
183 __sync_task_rss_stat(task, mm);
187 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
188 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
190 static void check_sync_rss_stat(struct task_struct *task)
197 * If a p?d_bad entry is found while walking page tables, report
198 * the error, before resetting entry to p?d_none. Usually (but
199 * very seldom) called out from the p?d_none_or_clear_bad macros.
202 void pgd_clear_bad(pgd_t *pgd)
208 void pud_clear_bad(pud_t *pud)
214 void pmd_clear_bad(pmd_t *pmd)
221 * Note: this doesn't free the actual pages themselves. That
222 * has been handled earlier when unmapping all the memory regions.
224 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
227 pgtable_t token = pmd_pgtable(*pmd);
229 pte_free_tlb(tlb, token, addr);
233 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
234 unsigned long addr, unsigned long end,
235 unsigned long floor, unsigned long ceiling)
242 pmd = pmd_offset(pud, addr);
244 next = pmd_addr_end(addr, end);
245 if (pmd_none_or_clear_bad(pmd))
247 free_pte_range(tlb, pmd, addr);
248 } while (pmd++, addr = next, addr != end);
258 if (end - 1 > ceiling - 1)
261 pmd = pmd_offset(pud, start);
263 pmd_free_tlb(tlb, pmd, start);
266 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
267 unsigned long addr, unsigned long end,
268 unsigned long floor, unsigned long ceiling)
275 pud = pud_offset(pgd, addr);
277 next = pud_addr_end(addr, end);
278 if (pud_none_or_clear_bad(pud))
280 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
281 } while (pud++, addr = next, addr != end);
287 ceiling &= PGDIR_MASK;
291 if (end - 1 > ceiling - 1)
294 pud = pud_offset(pgd, start);
296 pud_free_tlb(tlb, pud, start);
300 * This function frees user-level page tables of a process.
302 * Must be called with pagetable lock held.
304 void free_pgd_range(struct mmu_gather *tlb,
305 unsigned long addr, unsigned long end,
306 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)
353 pgd = pgd_offset(tlb->mm, addr);
355 next = pgd_addr_end(addr, end);
356 if (pgd_none_or_clear_bad(pgd))
358 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
359 } while (pgd++, addr = next, addr != end);
362 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
363 unsigned long floor, unsigned long ceiling)
366 struct vm_area_struct *next = vma->vm_next;
367 unsigned long addr = vma->vm_start;
370 * Hide vma from rmap and truncate_pagecache before freeing
373 unlink_anon_vmas(vma);
374 unlink_file_vma(vma);
376 if (is_vm_hugetlb_page(vma)) {
377 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
378 floor, next? next->vm_start: ceiling);
381 * Optimization: gather nearby vmas into one call down
383 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
384 && !is_vm_hugetlb_page(next)) {
387 unlink_anon_vmas(vma);
388 unlink_file_vma(vma);
390 free_pgd_range(tlb, addr, vma->vm_end,
391 floor, next? next->vm_start: ceiling);
397 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
399 pgtable_t new = pte_alloc_one(mm, address);
404 * Ensure all pte setup (eg. pte page lock and page clearing) are
405 * visible before the pte is made visible to other CPUs by being
406 * put into page tables.
408 * The other side of the story is the pointer chasing in the page
409 * table walking code (when walking the page table without locking;
410 * ie. most of the time). Fortunately, these data accesses consist
411 * of a chain of data-dependent loads, meaning most CPUs (alpha
412 * being the notable exception) will already guarantee loads are
413 * seen in-order. See the alpha page table accessors for the
414 * smp_read_barrier_depends() barriers in page table walking code.
416 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
418 spin_lock(&mm->page_table_lock);
419 if (!pmd_present(*pmd)) { /* Has another populated it ? */
421 pmd_populate(mm, pmd, new);
424 spin_unlock(&mm->page_table_lock);
430 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
432 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
436 smp_wmb(); /* See comment in __pte_alloc */
438 spin_lock(&init_mm.page_table_lock);
439 if (!pmd_present(*pmd)) { /* Has another populated it ? */
440 pmd_populate_kernel(&init_mm, pmd, new);
443 spin_unlock(&init_mm.page_table_lock);
445 pte_free_kernel(&init_mm, new);
449 static inline void init_rss_vec(int *rss)
451 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
454 static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
458 if (current->mm == mm)
459 sync_mm_rss(current, mm);
460 for (i = 0; i < NR_MM_COUNTERS; i++)
462 add_mm_counter(mm, i, rss[i]);
466 * This function is called to print an error when a bad pte
467 * is found. For example, we might have a PFN-mapped pte in
468 * a region that doesn't allow it.
470 * The calling function must still handle the error.
472 static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
473 pte_t pte, struct page *page)
475 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
476 pud_t *pud = pud_offset(pgd, addr);
477 pmd_t *pmd = pmd_offset(pud, addr);
478 struct address_space *mapping;
480 static unsigned long resume;
481 static unsigned long nr_shown;
482 static unsigned long nr_unshown;
485 * Allow a burst of 60 reports, then keep quiet for that minute;
486 * or allow a steady drip of one report per second.
488 if (nr_shown == 60) {
489 if (time_before(jiffies, resume)) {
495 "BUG: Bad page map: %lu messages suppressed\n",
502 resume = jiffies + 60 * HZ;
504 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
505 index = linear_page_index(vma, addr);
508 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
510 (long long)pte_val(pte), (long long)pmd_val(*pmd));
514 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
515 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
517 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
520 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
521 (unsigned long)vma->vm_ops->fault);
522 if (vma->vm_file && vma->vm_file->f_op)
523 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
524 (unsigned long)vma->vm_file->f_op->mmap);
526 add_taint(TAINT_BAD_PAGE);
529 static inline int is_cow_mapping(unsigned int flags)
531 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
535 static inline int is_zero_pfn(unsigned long pfn)
537 return pfn == zero_pfn;
542 static inline unsigned long my_zero_pfn(unsigned long addr)
549 * vm_normal_page -- This function gets the "struct page" associated with a pte.
551 * "Special" mappings do not wish to be associated with a "struct page" (either
552 * it doesn't exist, or it exists but they don't want to touch it). In this
553 * case, NULL is returned here. "Normal" mappings do have a struct page.
555 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
556 * pte bit, in which case this function is trivial. Secondly, an architecture
557 * may not have a spare pte bit, which requires a more complicated scheme,
560 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
561 * special mapping (even if there are underlying and valid "struct pages").
562 * COWed pages of a VM_PFNMAP are always normal.
564 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
565 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
566 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
567 * mapping will always honor the rule
569 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
571 * And for normal mappings this is false.
573 * This restricts such mappings to be a linear translation from virtual address
574 * to pfn. To get around this restriction, we allow arbitrary mappings so long
575 * as the vma is not a COW mapping; in that case, we know that all ptes are
576 * special (because none can have been COWed).
579 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
581 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
582 * page" backing, however the difference is that _all_ pages with a struct
583 * page (that is, those where pfn_valid is true) are refcounted and considered
584 * normal pages by the VM. The disadvantage is that pages are refcounted
585 * (which can be slower and simply not an option for some PFNMAP users). The
586 * advantage is that we don't have to follow the strict linearity rule of
587 * PFNMAP mappings in order to support COWable mappings.
590 #ifdef __HAVE_ARCH_PTE_SPECIAL
591 # define HAVE_PTE_SPECIAL 1
593 # define HAVE_PTE_SPECIAL 0
595 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
598 unsigned long pfn = pte_pfn(pte);
600 if (HAVE_PTE_SPECIAL) {
601 if (likely(!pte_special(pte)))
603 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
605 if (!is_zero_pfn(pfn))
606 print_bad_pte(vma, addr, pte, NULL);
610 /* !HAVE_PTE_SPECIAL case follows: */
612 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
613 if (vma->vm_flags & VM_MIXEDMAP) {
619 off = (addr - vma->vm_start) >> PAGE_SHIFT;
620 if (pfn == vma->vm_pgoff + off)
622 if (!is_cow_mapping(vma->vm_flags))
627 if (is_zero_pfn(pfn))
630 if (unlikely(pfn > highest_memmap_pfn)) {
631 print_bad_pte(vma, addr, pte, NULL);
636 * NOTE! We still have PageReserved() pages in the page tables.
637 * eg. VDSO mappings can cause them to exist.
640 return pfn_to_page(pfn);
644 * copy one vm_area from one task to the other. Assumes the page tables
645 * already present in the new task to be cleared in the whole range
646 * covered by this vma.
649 static inline unsigned long
650 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
651 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
652 unsigned long addr, int *rss)
654 unsigned long vm_flags = vma->vm_flags;
655 pte_t pte = *src_pte;
658 /* pte contains position in swap or file, so copy. */
659 if (unlikely(!pte_present(pte))) {
660 if (!pte_file(pte)) {
661 swp_entry_t entry = pte_to_swp_entry(pte);
663 if (swap_duplicate(entry) < 0)
666 /* make sure dst_mm is on swapoff's mmlist. */
667 if (unlikely(list_empty(&dst_mm->mmlist))) {
668 spin_lock(&mmlist_lock);
669 if (list_empty(&dst_mm->mmlist))
670 list_add(&dst_mm->mmlist,
672 spin_unlock(&mmlist_lock);
674 if (likely(!non_swap_entry(entry)))
676 else if (is_write_migration_entry(entry) &&
677 is_cow_mapping(vm_flags)) {
679 * COW mappings require pages in both parent
680 * and child to be set to read.
682 make_migration_entry_read(&entry);
683 pte = swp_entry_to_pte(entry);
684 set_pte_at(src_mm, addr, src_pte, pte);
691 * If it's a COW mapping, write protect it both
692 * in the parent and the child
694 if (is_cow_mapping(vm_flags)) {
695 ptep_set_wrprotect(src_mm, addr, src_pte);
696 pte = pte_wrprotect(pte);
700 * If it's a shared mapping, mark it clean in
703 if (vm_flags & VM_SHARED)
704 pte = pte_mkclean(pte);
705 pte = pte_mkold(pte);
707 page = vm_normal_page(vma, addr, pte);
718 set_pte_at(dst_mm, addr, dst_pte, pte);
722 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
723 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
724 unsigned long addr, unsigned long end)
726 pte_t *orig_src_pte, *orig_dst_pte;
727 pte_t *src_pte, *dst_pte;
728 spinlock_t *src_ptl, *dst_ptl;
730 int rss[NR_MM_COUNTERS];
731 swp_entry_t entry = (swp_entry_t){0};
736 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
739 src_pte = pte_offset_map_nested(src_pmd, addr);
740 src_ptl = pte_lockptr(src_mm, src_pmd);
741 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
742 orig_src_pte = src_pte;
743 orig_dst_pte = dst_pte;
744 arch_enter_lazy_mmu_mode();
748 * We are holding two locks at this point - either of them
749 * could generate latencies in another task on another CPU.
751 if (progress >= 32) {
753 if (need_resched() ||
754 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
757 if (pte_none(*src_pte)) {
761 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
766 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
768 arch_leave_lazy_mmu_mode();
769 spin_unlock(src_ptl);
770 pte_unmap_nested(orig_src_pte);
771 add_mm_rss_vec(dst_mm, rss);
772 pte_unmap_unlock(orig_dst_pte, dst_ptl);
776 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
785 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
786 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
787 unsigned long addr, unsigned long end)
789 pmd_t *src_pmd, *dst_pmd;
792 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
795 src_pmd = pmd_offset(src_pud, addr);
797 next = pmd_addr_end(addr, end);
798 if (pmd_none_or_clear_bad(src_pmd))
800 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
803 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
807 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
808 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
809 unsigned long addr, unsigned long end)
811 pud_t *src_pud, *dst_pud;
814 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
817 src_pud = pud_offset(src_pgd, addr);
819 next = pud_addr_end(addr, end);
820 if (pud_none_or_clear_bad(src_pud))
822 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
825 } while (dst_pud++, src_pud++, addr = next, addr != end);
829 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
830 struct vm_area_struct *vma)
832 pgd_t *src_pgd, *dst_pgd;
834 unsigned long addr = vma->vm_start;
835 unsigned long end = vma->vm_end;
839 * Don't copy ptes where a page fault will fill them correctly.
840 * Fork becomes much lighter when there are big shared or private
841 * readonly mappings. The tradeoff is that copy_page_range is more
842 * efficient than faulting.
844 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
849 if (is_vm_hugetlb_page(vma))
850 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
852 if (unlikely(is_pfn_mapping(vma))) {
854 * We do not free on error cases below as remove_vma
855 * gets called on error from higher level routine
857 ret = track_pfn_vma_copy(vma);
863 * We need to invalidate the secondary MMU mappings only when
864 * there could be a permission downgrade on the ptes of the
865 * parent mm. And a permission downgrade will only happen if
866 * is_cow_mapping() returns true.
868 if (is_cow_mapping(vma->vm_flags))
869 mmu_notifier_invalidate_range_start(src_mm, addr, end);
872 dst_pgd = pgd_offset(dst_mm, addr);
873 src_pgd = pgd_offset(src_mm, addr);
875 next = pgd_addr_end(addr, end);
876 if (pgd_none_or_clear_bad(src_pgd))
878 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
883 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
885 if (is_cow_mapping(vma->vm_flags))
886 mmu_notifier_invalidate_range_end(src_mm,
891 static unsigned long zap_pte_range(struct mmu_gather *tlb,
892 struct vm_area_struct *vma, pmd_t *pmd,
893 unsigned long addr, unsigned long end,
894 long *zap_work, struct zap_details *details)
896 struct mm_struct *mm = tlb->mm;
899 int rss[NR_MM_COUNTERS];
903 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
904 arch_enter_lazy_mmu_mode();
907 if (pte_none(ptent)) {
912 (*zap_work) -= PAGE_SIZE;
914 if (pte_present(ptent)) {
917 page = vm_normal_page(vma, addr, ptent);
918 if (unlikely(details) && page) {
920 * unmap_shared_mapping_pages() wants to
921 * invalidate cache without truncating:
922 * unmap shared but keep private pages.
924 if (details->check_mapping &&
925 details->check_mapping != page->mapping)
928 * Each page->index must be checked when
929 * invalidating or truncating nonlinear.
931 if (details->nonlinear_vma &&
932 (page->index < details->first_index ||
933 page->index > details->last_index))
936 ptent = ptep_get_and_clear_full(mm, addr, pte,
938 tlb_remove_tlb_entry(tlb, pte, addr);
941 if (unlikely(details) && details->nonlinear_vma
942 && linear_page_index(details->nonlinear_vma,
943 addr) != page->index)
944 set_pte_at(mm, addr, pte,
945 pgoff_to_pte(page->index));
949 if (pte_dirty(ptent))
950 set_page_dirty(page);
951 if (pte_young(ptent) &&
952 likely(!VM_SequentialReadHint(vma)))
953 mark_page_accessed(page);
956 page_remove_rmap(page);
957 if (unlikely(page_mapcount(page) < 0))
958 print_bad_pte(vma, addr, ptent, page);
959 tlb_remove_page(tlb, page);
963 * If details->check_mapping, we leave swap entries;
964 * if details->nonlinear_vma, we leave file entries.
966 if (unlikely(details))
968 if (pte_file(ptent)) {
969 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
970 print_bad_pte(vma, addr, ptent, NULL);
972 swp_entry_t entry = pte_to_swp_entry(ptent);
974 if (!non_swap_entry(entry))
976 if (unlikely(!free_swap_and_cache(entry)))
977 print_bad_pte(vma, addr, ptent, NULL);
979 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
980 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
982 add_mm_rss_vec(mm, rss);
983 arch_leave_lazy_mmu_mode();
984 pte_unmap_unlock(pte - 1, ptl);
989 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
990 struct vm_area_struct *vma, pud_t *pud,
991 unsigned long addr, unsigned long end,
992 long *zap_work, struct zap_details *details)
997 pmd = pmd_offset(pud, addr);
999 next = pmd_addr_end(addr, end);
1000 if (pmd_none_or_clear_bad(pmd)) {
1004 next = zap_pte_range(tlb, vma, pmd, addr, next,
1006 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
1011 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1012 struct vm_area_struct *vma, pgd_t *pgd,
1013 unsigned long addr, unsigned long end,
1014 long *zap_work, struct zap_details *details)
1019 pud = pud_offset(pgd, addr);
1021 next = pud_addr_end(addr, end);
1022 if (pud_none_or_clear_bad(pud)) {
1026 next = zap_pmd_range(tlb, vma, pud, addr, next,
1028 } while (pud++, addr = next, (addr != end && *zap_work > 0));
1033 static unsigned long unmap_page_range(struct mmu_gather *tlb,
1034 struct vm_area_struct *vma,
1035 unsigned long addr, unsigned long end,
1036 long *zap_work, struct zap_details *details)
1041 if (details && !details->check_mapping && !details->nonlinear_vma)
1044 BUG_ON(addr >= end);
1045 mem_cgroup_uncharge_start();
1046 tlb_start_vma(tlb, vma);
1047 pgd = pgd_offset(vma->vm_mm, addr);
1049 next = pgd_addr_end(addr, end);
1050 if (pgd_none_or_clear_bad(pgd)) {
1054 next = zap_pud_range(tlb, vma, pgd, addr, next,
1056 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
1057 tlb_end_vma(tlb, vma);
1058 mem_cgroup_uncharge_end();
1063 #ifdef CONFIG_PREEMPT
1064 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
1066 /* No preempt: go for improved straight-line efficiency */
1067 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
1071 * unmap_vmas - unmap a range of memory covered by a list of vma's
1072 * @tlbp: address of the caller's struct mmu_gather
1073 * @vma: the starting vma
1074 * @start_addr: virtual address at which to start unmapping
1075 * @end_addr: virtual address at which to end unmapping
1076 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
1077 * @details: details of nonlinear truncation or shared cache invalidation
1079 * Returns the end address of the unmapping (restart addr if interrupted).
1081 * Unmap all pages in the vma list.
1083 * We aim to not hold locks for too long (for scheduling latency reasons).
1084 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
1085 * return the ending mmu_gather to the caller.
1087 * Only addresses between `start' and `end' will be unmapped.
1089 * The VMA list must be sorted in ascending virtual address order.
1091 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1092 * range after unmap_vmas() returns. So the only responsibility here is to
1093 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1094 * drops the lock and schedules.
1096 unsigned long unmap_vmas(struct mmu_gather **tlbp,
1097 struct vm_area_struct *vma, unsigned long start_addr,
1098 unsigned long end_addr, unsigned long *nr_accounted,
1099 struct zap_details *details)
1101 long zap_work = ZAP_BLOCK_SIZE;
1102 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
1103 int tlb_start_valid = 0;
1104 unsigned long start = start_addr;
1105 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
1106 int fullmm = (*tlbp)->fullmm;
1107 struct mm_struct *mm = vma->vm_mm;
1109 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1110 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
1113 start = max(vma->vm_start, start_addr);
1114 if (start >= vma->vm_end)
1116 end = min(vma->vm_end, end_addr);
1117 if (end <= vma->vm_start)
1120 if (vma->vm_flags & VM_ACCOUNT)
1121 *nr_accounted += (end - start) >> PAGE_SHIFT;
1123 if (unlikely(is_pfn_mapping(vma)))
1124 untrack_pfn_vma(vma, 0, 0);
1126 while (start != end) {
1127 if (!tlb_start_valid) {
1129 tlb_start_valid = 1;
1132 if (unlikely(is_vm_hugetlb_page(vma))) {
1134 * It is undesirable to test vma->vm_file as it
1135 * should be non-null for valid hugetlb area.
1136 * However, vm_file will be NULL in the error
1137 * cleanup path of do_mmap_pgoff. When
1138 * hugetlbfs ->mmap method fails,
1139 * do_mmap_pgoff() nullifies vma->vm_file
1140 * before calling this function to clean up.
1141 * Since no pte has actually been setup, it is
1142 * safe to do nothing in this case.
1145 unmap_hugepage_range(vma, start, end, NULL);
1146 zap_work -= (end - start) /
1147 pages_per_huge_page(hstate_vma(vma));
1152 start = unmap_page_range(*tlbp, vma,
1153 start, end, &zap_work, details);
1156 BUG_ON(start != end);
1160 tlb_finish_mmu(*tlbp, tlb_start, start);
1162 if (need_resched() ||
1163 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
1171 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
1172 tlb_start_valid = 0;
1173 zap_work = ZAP_BLOCK_SIZE;
1177 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1178 return start; /* which is now the end (or restart) address */
1182 * zap_page_range - remove user pages in a given range
1183 * @vma: vm_area_struct holding the applicable pages
1184 * @address: starting address of pages to zap
1185 * @size: number of bytes to zap
1186 * @details: details of nonlinear truncation or shared cache invalidation
1188 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
1189 unsigned long size, struct zap_details *details)
1191 struct mm_struct *mm = vma->vm_mm;
1192 struct mmu_gather *tlb;
1193 unsigned long end = address + size;
1194 unsigned long nr_accounted = 0;
1197 tlb = tlb_gather_mmu(mm, 0);
1198 update_hiwater_rss(mm);
1199 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
1201 tlb_finish_mmu(tlb, address, end);
1206 * zap_vma_ptes - remove ptes mapping the vma
1207 * @vma: vm_area_struct holding ptes to be zapped
1208 * @address: starting address of pages to zap
1209 * @size: number of bytes to zap
1211 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1213 * The entire address range must be fully contained within the vma.
1215 * Returns 0 if successful.
1217 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1220 if (address < vma->vm_start || address + size > vma->vm_end ||
1221 !(vma->vm_flags & VM_PFNMAP))
1223 zap_page_range(vma, address, size, NULL);
1226 EXPORT_SYMBOL_GPL(zap_vma_ptes);
1229 * follow_page - look up a page descriptor from a user-virtual address
1230 * @vma: vm_area_struct mapping @address
1231 * @address: virtual address to look up
1232 * @flags: flags modifying lookup behaviour
1234 * @flags can have FOLL_ flags set, defined in <linux/mm.h>
1236 * Returns the mapped (struct page *), %NULL if no mapping exists, or
1237 * an error pointer if there is a mapping to something not represented
1238 * by a page descriptor (see also vm_normal_page()).
1240 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1249 struct mm_struct *mm = vma->vm_mm;
1251 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1252 if (!IS_ERR(page)) {
1253 BUG_ON(flags & FOLL_GET);
1258 pgd = pgd_offset(mm, address);
1259 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1262 pud = pud_offset(pgd, address);
1265 if (pud_huge(*pud)) {
1266 BUG_ON(flags & FOLL_GET);
1267 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1270 if (unlikely(pud_bad(*pud)))
1273 pmd = pmd_offset(pud, address);
1276 if (pmd_huge(*pmd)) {
1277 BUG_ON(flags & FOLL_GET);
1278 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1281 if (unlikely(pmd_bad(*pmd)))
1284 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1287 if (!pte_present(pte))
1289 if ((flags & FOLL_WRITE) && !pte_write(pte))
1292 page = vm_normal_page(vma, address, pte);
1293 if (unlikely(!page)) {
1294 if ((flags & FOLL_DUMP) ||
1295 !is_zero_pfn(pte_pfn(pte)))
1297 page = pte_page(pte);
1300 if (flags & FOLL_GET)
1302 if (flags & FOLL_TOUCH) {
1303 if ((flags & FOLL_WRITE) &&
1304 !pte_dirty(pte) && !PageDirty(page))
1305 set_page_dirty(page);
1307 * pte_mkyoung() would be more correct here, but atomic care
1308 * is needed to avoid losing the dirty bit: it is easier to use
1309 * mark_page_accessed().
1311 mark_page_accessed(page);
1314 pte_unmap_unlock(ptep, ptl);
1319 pte_unmap_unlock(ptep, ptl);
1320 return ERR_PTR(-EFAULT);
1323 pte_unmap_unlock(ptep, ptl);
1329 * When core dumping an enormous anonymous area that nobody
1330 * has touched so far, we don't want to allocate unnecessary pages or
1331 * page tables. Return error instead of NULL to skip handle_mm_fault,
1332 * then get_dump_page() will return NULL to leave a hole in the dump.
1333 * But we can only make this optimization where a hole would surely
1334 * be zero-filled if handle_mm_fault() actually did handle it.
1336 if ((flags & FOLL_DUMP) &&
1337 (!vma->vm_ops || !vma->vm_ops->fault))
1338 return ERR_PTR(-EFAULT);
1342 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1343 unsigned long start, int nr_pages, unsigned int gup_flags,
1344 struct page **pages, struct vm_area_struct **vmas)
1347 unsigned long vm_flags;
1352 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1355 * Require read or write permissions.
1356 * If FOLL_FORCE is set, we only require the "MAY" flags.
1358 vm_flags = (gup_flags & FOLL_WRITE) ?
1359 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1360 vm_flags &= (gup_flags & FOLL_FORCE) ?
1361 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1365 struct vm_area_struct *vma;
1367 vma = find_extend_vma(mm, start);
1368 if (!vma && in_gate_area(tsk, start)) {
1369 unsigned long pg = start & PAGE_MASK;
1370 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1376 /* user gate pages are read-only */
1377 if (gup_flags & FOLL_WRITE)
1378 return i ? : -EFAULT;
1380 pgd = pgd_offset_k(pg);
1382 pgd = pgd_offset_gate(mm, pg);
1383 BUG_ON(pgd_none(*pgd));
1384 pud = pud_offset(pgd, pg);
1385 BUG_ON(pud_none(*pud));
1386 pmd = pmd_offset(pud, pg);
1388 return i ? : -EFAULT;
1389 pte = pte_offset_map(pmd, pg);
1390 if (pte_none(*pte)) {
1392 return i ? : -EFAULT;
1397 page = vm_normal_page(gate_vma, start, *pte);
1399 if (!(gup_flags & FOLL_DUMP) &&
1400 is_zero_pfn(pte_pfn(*pte)))
1401 page = pte_page(*pte);
1404 return i ? : -EFAULT;
1420 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1421 !(vm_flags & vma->vm_flags))
1422 return i ? : -EFAULT;
1424 if (is_vm_hugetlb_page(vma)) {
1425 i = follow_hugetlb_page(mm, vma, pages, vmas,
1426 &start, &nr_pages, i, gup_flags);
1432 unsigned int foll_flags = gup_flags;
1435 * If we have a pending SIGKILL, don't keep faulting
1436 * pages and potentially allocating memory.
1438 if (unlikely(fatal_signal_pending(current)))
1439 return i ? i : -ERESTARTSYS;
1442 while (!(page = follow_page(vma, start, foll_flags))) {
1445 ret = handle_mm_fault(mm, vma, start,
1446 (foll_flags & FOLL_WRITE) ?
1447 FAULT_FLAG_WRITE : 0);
1449 if (ret & VM_FAULT_ERROR) {
1450 if (ret & VM_FAULT_OOM)
1451 return i ? i : -ENOMEM;
1453 (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
1454 return i ? i : -EFAULT;
1457 if (ret & VM_FAULT_MAJOR)
1463 * The VM_FAULT_WRITE bit tells us that
1464 * do_wp_page has broken COW when necessary,
1465 * even if maybe_mkwrite decided not to set
1466 * pte_write. We can thus safely do subsequent
1467 * page lookups as if they were reads. But only
1468 * do so when looping for pte_write is futile:
1469 * in some cases userspace may also be wanting
1470 * to write to the gotten user page, which a
1471 * read fault here might prevent (a readonly
1472 * page might get reCOWed by userspace write).
1474 if ((ret & VM_FAULT_WRITE) &&
1475 !(vma->vm_flags & VM_WRITE))
1476 foll_flags &= ~FOLL_WRITE;
1481 return i ? i : PTR_ERR(page);
1485 flush_anon_page(vma, page, start);
1486 flush_dcache_page(page);
1493 } while (nr_pages && start < vma->vm_end);
1499 * get_user_pages() - pin user pages in memory
1500 * @tsk: task_struct of target task
1501 * @mm: mm_struct of target mm
1502 * @start: starting user address
1503 * @nr_pages: number of pages from start to pin
1504 * @write: whether pages will be written to by the caller
1505 * @force: whether to force write access even if user mapping is
1506 * readonly. This will result in the page being COWed even
1507 * in MAP_SHARED mappings. You do not want this.
1508 * @pages: array that receives pointers to the pages pinned.
1509 * Should be at least nr_pages long. Or NULL, if caller
1510 * only intends to ensure the pages are faulted in.
1511 * @vmas: array of pointers to vmas corresponding to each page.
1512 * Or NULL if the caller does not require them.
1514 * Returns number of pages pinned. This may be fewer than the number
1515 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1516 * were pinned, returns -errno. Each page returned must be released
1517 * with a put_page() call when it is finished with. vmas will only
1518 * remain valid while mmap_sem is held.
1520 * Must be called with mmap_sem held for read or write.
1522 * get_user_pages walks a process's page tables and takes a reference to
1523 * each struct page that each user address corresponds to at a given
1524 * instant. That is, it takes the page that would be accessed if a user
1525 * thread accesses the given user virtual address at that instant.
1527 * This does not guarantee that the page exists in the user mappings when
1528 * get_user_pages returns, and there may even be a completely different
1529 * page there in some cases (eg. if mmapped pagecache has been invalidated
1530 * and subsequently re faulted). However it does guarantee that the page
1531 * won't be freed completely. And mostly callers simply care that the page
1532 * contains data that was valid *at some point in time*. Typically, an IO
1533 * or similar operation cannot guarantee anything stronger anyway because
1534 * locks can't be held over the syscall boundary.
1536 * If write=0, the page must not be written to. If the page is written to,
1537 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1538 * after the page is finished with, and before put_page is called.
1540 * get_user_pages is typically used for fewer-copy IO operations, to get a
1541 * handle on the memory by some means other than accesses via the user virtual
1542 * addresses. The pages may be submitted for DMA to devices or accessed via
1543 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1544 * use the correct cache flushing APIs.
1546 * See also get_user_pages_fast, for performance critical applications.
1548 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1549 unsigned long start, int nr_pages, int write, int force,
1550 struct page **pages, struct vm_area_struct **vmas)
1552 int flags = FOLL_TOUCH;
1557 flags |= FOLL_WRITE;
1559 flags |= FOLL_FORCE;
1561 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
1563 EXPORT_SYMBOL(get_user_pages);
1566 * get_dump_page() - pin user page in memory while writing it to core dump
1567 * @addr: user address
1569 * Returns struct page pointer of user page pinned for dump,
1570 * to be freed afterwards by page_cache_release() or put_page().
1572 * Returns NULL on any kind of failure - a hole must then be inserted into
1573 * the corefile, to preserve alignment with its headers; and also returns
1574 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
1575 * allowing a hole to be left in the corefile to save diskspace.
1577 * Called without mmap_sem, but after all other threads have been killed.
1579 #ifdef CONFIG_ELF_CORE
1580 struct page *get_dump_page(unsigned long addr)
1582 struct vm_area_struct *vma;
1585 if (__get_user_pages(current, current->mm, addr, 1,
1586 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
1588 flush_cache_page(vma, addr, page_to_pfn(page));
1591 #endif /* CONFIG_ELF_CORE */
1593 pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1596 pgd_t * pgd = pgd_offset(mm, addr);
1597 pud_t * pud = pud_alloc(mm, pgd, addr);
1599 pmd_t * pmd = pmd_alloc(mm, pud, addr);
1601 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1607 * This is the old fallback for page remapping.
1609 * For historical reasons, it only allows reserved pages. Only
1610 * old drivers should use this, and they needed to mark their
1611 * pages reserved for the old functions anyway.
1613 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1614 struct page *page, pgprot_t prot)
1616 struct mm_struct *mm = vma->vm_mm;
1625 flush_dcache_page(page);
1626 pte = get_locked_pte(mm, addr, &ptl);
1630 if (!pte_none(*pte))
1633 /* Ok, finally just insert the thing.. */
1635 inc_mm_counter_fast(mm, MM_FILEPAGES);
1636 page_add_file_rmap(page);
1637 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1640 pte_unmap_unlock(pte, ptl);
1643 pte_unmap_unlock(pte, ptl);
1649 * vm_insert_page - insert single page into user vma
1650 * @vma: user vma to map to
1651 * @addr: target user address of this page
1652 * @page: source kernel page
1654 * This allows drivers to insert individual pages they've allocated
1657 * The page has to be a nice clean _individual_ kernel allocation.
1658 * If you allocate a compound page, you need to have marked it as
1659 * such (__GFP_COMP), or manually just split the page up yourself
1660 * (see split_page()).
1662 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1663 * took an arbitrary page protection parameter. This doesn't allow
1664 * that. Your vma protection will have to be set up correctly, which
1665 * means that if you want a shared writable mapping, you'd better
1666 * ask for a shared writable mapping!
1668 * The page does not need to be reserved.
1670 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1673 if (addr < vma->vm_start || addr >= vma->vm_end)
1675 if (!page_count(page))
1677 vma->vm_flags |= VM_INSERTPAGE;
1678 return insert_page(vma, addr, page, vma->vm_page_prot);
1680 EXPORT_SYMBOL(vm_insert_page);
1682 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1683 unsigned long pfn, pgprot_t prot)
1685 struct mm_struct *mm = vma->vm_mm;
1691 pte = get_locked_pte(mm, addr, &ptl);
1695 if (!pte_none(*pte))
1698 /* Ok, finally just insert the thing.. */
1699 entry = pte_mkspecial(pfn_pte(pfn, prot));
1700 set_pte_at(mm, addr, pte, entry);
1701 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
1705 pte_unmap_unlock(pte, ptl);
1711 * vm_insert_pfn - insert single pfn into user vma
1712 * @vma: user vma to map to
1713 * @addr: target user address of this page
1714 * @pfn: source kernel pfn
1716 * Similar to vm_inert_page, this allows drivers to insert individual pages
1717 * they've allocated into a user vma. Same comments apply.
1719 * This function should only be called from a vm_ops->fault handler, and
1720 * in that case the handler should return NULL.
1722 * vma cannot be a COW mapping.
1724 * As this is called only for pages that do not currently exist, we
1725 * do not need to flush old virtual caches or the TLB.
1727 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1731 pgprot_t pgprot = vma->vm_page_prot;
1733 * Technically, architectures with pte_special can avoid all these
1734 * restrictions (same for remap_pfn_range). However we would like
1735 * consistency in testing and feature parity among all, so we should
1736 * try to keep these invariants in place for everybody.
1738 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1739 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1740 (VM_PFNMAP|VM_MIXEDMAP));
1741 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1742 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
1744 if (addr < vma->vm_start || addr >= vma->vm_end)
1746 if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
1749 ret = insert_pfn(vma, addr, pfn, pgprot);
1752 untrack_pfn_vma(vma, pfn, PAGE_SIZE);
1756 EXPORT_SYMBOL(vm_insert_pfn);
1758 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1761 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1763 if (addr < vma->vm_start || addr >= vma->vm_end)
1767 * If we don't have pte special, then we have to use the pfn_valid()
1768 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1769 * refcount the page if pfn_valid is true (hence insert_page rather
1770 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1771 * without pte special, it would there be refcounted as a normal page.
1773 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1776 page = pfn_to_page(pfn);
1777 return insert_page(vma, addr, page, vma->vm_page_prot);
1779 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1781 EXPORT_SYMBOL(vm_insert_mixed);
1784 * maps a range of physical memory into the requested pages. the old
1785 * mappings are removed. any references to nonexistent pages results
1786 * in null mappings (currently treated as "copy-on-access")
1788 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1789 unsigned long addr, unsigned long end,
1790 unsigned long pfn, pgprot_t prot)
1795 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1798 arch_enter_lazy_mmu_mode();
1800 BUG_ON(!pte_none(*pte));
1801 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
1803 } while (pte++, addr += PAGE_SIZE, addr != end);
1804 arch_leave_lazy_mmu_mode();
1805 pte_unmap_unlock(pte - 1, ptl);
1809 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1810 unsigned long addr, unsigned long end,
1811 unsigned long pfn, pgprot_t prot)
1816 pfn -= addr >> PAGE_SHIFT;
1817 pmd = pmd_alloc(mm, pud, addr);
1821 next = pmd_addr_end(addr, end);
1822 if (remap_pte_range(mm, pmd, addr, next,
1823 pfn + (addr >> PAGE_SHIFT), prot))
1825 } while (pmd++, addr = next, addr != end);
1829 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1830 unsigned long addr, unsigned long end,
1831 unsigned long pfn, pgprot_t prot)
1836 pfn -= addr >> PAGE_SHIFT;
1837 pud = pud_alloc(mm, pgd, addr);
1841 next = pud_addr_end(addr, end);
1842 if (remap_pmd_range(mm, pud, addr, next,
1843 pfn + (addr >> PAGE_SHIFT), prot))
1845 } while (pud++, addr = next, addr != end);
1850 * remap_pfn_range - remap kernel memory to userspace
1851 * @vma: user vma to map to
1852 * @addr: target user address to start at
1853 * @pfn: physical address of kernel memory
1854 * @size: size of map area
1855 * @prot: page protection flags for this mapping
1857 * Note: this is only safe if the mm semaphore is held when called.
1859 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1860 unsigned long pfn, unsigned long size, pgprot_t prot)
1864 unsigned long end = addr + PAGE_ALIGN(size);
1865 struct mm_struct *mm = vma->vm_mm;
1869 * Physically remapped pages are special. Tell the
1870 * rest of the world about it:
1871 * VM_IO tells people not to look at these pages
1872 * (accesses can have side effects).
1873 * VM_RESERVED is specified all over the place, because
1874 * in 2.4 it kept swapout's vma scan off this vma; but
1875 * in 2.6 the LRU scan won't even find its pages, so this
1876 * flag means no more than count its pages in reserved_vm,
1877 * and omit it from core dump, even when VM_IO turned off.
1878 * VM_PFNMAP tells the core MM that the base pages are just
1879 * raw PFN mappings, and do not have a "struct page" associated
1882 * There's a horrible special case to handle copy-on-write
1883 * behaviour that some programs depend on. We mark the "original"
1884 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1886 if (addr == vma->vm_start && end == vma->vm_end) {
1887 vma->vm_pgoff = pfn;
1888 vma->vm_flags |= VM_PFN_AT_MMAP;
1889 } else if (is_cow_mapping(vma->vm_flags))
1892 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
1894 err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
1897 * To indicate that track_pfn related cleanup is not
1898 * needed from higher level routine calling unmap_vmas
1900 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
1901 vma->vm_flags &= ~VM_PFN_AT_MMAP;
1905 BUG_ON(addr >= end);
1906 pfn -= addr >> PAGE_SHIFT;
1907 pgd = pgd_offset(mm, addr);
1908 flush_cache_range(vma, addr, end);
1910 next = pgd_addr_end(addr, end);
1911 err = remap_pud_range(mm, pgd, addr, next,
1912 pfn + (addr >> PAGE_SHIFT), prot);
1915 } while (pgd++, addr = next, addr != end);
1918 untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
1922 EXPORT_SYMBOL(remap_pfn_range);
1924 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1925 unsigned long addr, unsigned long end,
1926 pte_fn_t fn, void *data)
1931 spinlock_t *uninitialized_var(ptl);
1933 pte = (mm == &init_mm) ?
1934 pte_alloc_kernel(pmd, addr) :
1935 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1939 BUG_ON(pmd_huge(*pmd));
1941 arch_enter_lazy_mmu_mode();
1943 token = pmd_pgtable(*pmd);
1946 err = fn(pte++, token, addr, data);
1949 } while (addr += PAGE_SIZE, addr != end);
1951 arch_leave_lazy_mmu_mode();
1954 pte_unmap_unlock(pte-1, ptl);
1958 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1959 unsigned long addr, unsigned long end,
1960 pte_fn_t fn, void *data)
1966 BUG_ON(pud_huge(*pud));
1968 pmd = pmd_alloc(mm, pud, addr);
1972 next = pmd_addr_end(addr, end);
1973 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1976 } while (pmd++, addr = next, addr != end);
1980 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1981 unsigned long addr, unsigned long end,
1982 pte_fn_t fn, void *data)
1988 pud = pud_alloc(mm, pgd, addr);
1992 next = pud_addr_end(addr, end);
1993 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1996 } while (pud++, addr = next, addr != end);
2001 * Scan a region of virtual memory, filling in page tables as necessary
2002 * and calling a provided function on each leaf page table.
2004 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2005 unsigned long size, pte_fn_t fn, void *data)
2009 unsigned long end = addr + size;
2012 BUG_ON(addr >= end);
2013 pgd = pgd_offset(mm, addr);
2015 next = pgd_addr_end(addr, end);
2016 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2019 } while (pgd++, addr = next, addr != end);
2023 EXPORT_SYMBOL_GPL(apply_to_page_range);
2026 * handle_pte_fault chooses page fault handler according to an entry
2027 * which was read non-atomically. Before making any commitment, on
2028 * those architectures or configurations (e.g. i386 with PAE) which
2029 * might give a mix of unmatched parts, do_swap_page and do_file_page
2030 * must check under lock before unmapping the pte and proceeding
2031 * (but do_wp_page is only called after already making such a check;
2032 * and do_anonymous_page and do_no_page can safely check later on).
2034 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2035 pte_t *page_table, pte_t orig_pte)
2038 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2039 if (sizeof(pte_t) > sizeof(unsigned long)) {
2040 spinlock_t *ptl = pte_lockptr(mm, pmd);
2042 same = pte_same(*page_table, orig_pte);
2046 pte_unmap(page_table);
2051 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
2052 * servicing faults for write access. In the normal case, do always want
2053 * pte_mkwrite. But get_user_pages can cause write faults for mappings
2054 * that do not have writing enabled, when used by access_process_vm.
2056 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
2058 if (likely(vma->vm_flags & VM_WRITE))
2059 pte = pte_mkwrite(pte);
2063 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2066 * If the source page was a PFN mapping, we don't have
2067 * a "struct page" for it. We do a best-effort copy by
2068 * just copying from the original user address. If that
2069 * fails, we just zero-fill it. Live with it.
2071 if (unlikely(!src)) {
2072 void *kaddr = kmap_atomic(dst, KM_USER0);
2073 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2076 * This really shouldn't fail, because the page is there
2077 * in the page tables. But it might just be unreadable,
2078 * in which case we just give up and fill the result with
2081 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2082 memset(kaddr, 0, PAGE_SIZE);
2083 kunmap_atomic(kaddr, KM_USER0);
2084 flush_dcache_page(dst);
2086 copy_user_highpage(dst, src, va, vma);
2090 * This routine handles present pages, when users try to write
2091 * to a shared page. It is done by copying the page to a new address
2092 * and decrementing the shared-page counter for the old page.
2094 * Note that this routine assumes that the protection checks have been
2095 * done by the caller (the low-level page fault routine in most cases).
2096 * Thus we can safely just mark it writable once we've done any necessary
2099 * We also mark the page dirty at this point even though the page will
2100 * change only once the write actually happens. This avoids a few races,
2101 * and potentially makes it more efficient.
2103 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2104 * but allow concurrent faults), with pte both mapped and locked.
2105 * We return with mmap_sem still held, but pte unmapped and unlocked.
2107 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2108 unsigned long address, pte_t *page_table, pmd_t *pmd,
2109 spinlock_t *ptl, pte_t orig_pte)
2111 struct page *old_page, *new_page;
2113 int reuse = 0, ret = 0;
2114 int page_mkwrite = 0;
2115 struct page *dirty_page = NULL;
2117 old_page = vm_normal_page(vma, address, orig_pte);
2120 * VM_MIXEDMAP !pfn_valid() case
2122 * We should not cow pages in a shared writeable mapping.
2123 * Just mark the pages writable as we can't do any dirty
2124 * accounting on raw pfn maps.
2126 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2127 (VM_WRITE|VM_SHARED))
2133 * Take out anonymous pages first, anonymous shared vmas are
2134 * not dirty accountable.
2136 if (PageAnon(old_page) && !PageKsm(old_page)) {
2137 if (!trylock_page(old_page)) {
2138 page_cache_get(old_page);
2139 pte_unmap_unlock(page_table, ptl);
2140 lock_page(old_page);
2141 page_table = pte_offset_map_lock(mm, pmd, address,
2143 if (!pte_same(*page_table, orig_pte)) {
2144 unlock_page(old_page);
2145 page_cache_release(old_page);
2148 page_cache_release(old_page);
2150 reuse = reuse_swap_page(old_page);
2153 * The page is all ours. Move it to our anon_vma so
2154 * the rmap code will not search our parent or siblings.
2155 * Protected against the rmap code by the page lock.
2157 page_move_anon_rmap(old_page, vma, address);
2158 unlock_page(old_page);
2159 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2160 (VM_WRITE|VM_SHARED))) {
2162 * Only catch write-faults on shared writable pages,
2163 * read-only shared pages can get COWed by
2164 * get_user_pages(.write=1, .force=1).
2166 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2167 struct vm_fault vmf;
2170 vmf.virtual_address = (void __user *)(address &
2172 vmf.pgoff = old_page->index;
2173 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2174 vmf.page = old_page;
2177 * Notify the address space that the page is about to
2178 * become writable so that it can prohibit this or wait
2179 * for the page to get into an appropriate state.
2181 * We do this without the lock held, so that it can
2182 * sleep if it needs to.
2184 page_cache_get(old_page);
2185 pte_unmap_unlock(page_table, ptl);
2187 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2189 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2191 goto unwritable_page;
2193 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2194 lock_page(old_page);
2195 if (!old_page->mapping) {
2196 ret = 0; /* retry the fault */
2197 unlock_page(old_page);
2198 goto unwritable_page;
2201 VM_BUG_ON(!PageLocked(old_page));
2204 * Since we dropped the lock we need to revalidate
2205 * the PTE as someone else may have changed it. If
2206 * they did, we just return, as we can count on the
2207 * MMU to tell us if they didn't also make it writable.
2209 page_table = pte_offset_map_lock(mm, pmd, address,
2211 if (!pte_same(*page_table, orig_pte)) {
2212 unlock_page(old_page);
2213 page_cache_release(old_page);
2219 dirty_page = old_page;
2220 get_page(dirty_page);
2226 flush_cache_page(vma, address, pte_pfn(orig_pte));
2227 entry = pte_mkyoung(orig_pte);
2228 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2229 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2230 update_mmu_cache(vma, address, page_table);
2231 ret |= VM_FAULT_WRITE;
2236 * Ok, we need to copy. Oh, well..
2238 page_cache_get(old_page);
2240 pte_unmap_unlock(page_table, ptl);
2242 if (unlikely(anon_vma_prepare(vma)))
2245 if (is_zero_pfn(pte_pfn(orig_pte))) {
2246 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2250 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2253 cow_user_page(new_page, old_page, address, vma);
2255 __SetPageUptodate(new_page);
2258 * Don't let another task, with possibly unlocked vma,
2259 * keep the mlocked page.
2261 if ((vma->vm_flags & VM_LOCKED) && old_page) {
2262 lock_page(old_page); /* for LRU manipulation */
2263 clear_page_mlock(old_page);
2264 unlock_page(old_page);
2267 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2271 * Re-check the pte - we dropped the lock
2273 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2274 if (likely(pte_same(*page_table, orig_pte))) {
2276 if (!PageAnon(old_page)) {
2277 dec_mm_counter_fast(mm, MM_FILEPAGES);
2278 inc_mm_counter_fast(mm, MM_ANONPAGES);
2281 inc_mm_counter_fast(mm, MM_ANONPAGES);
2282 flush_cache_page(vma, address, pte_pfn(orig_pte));
2283 entry = mk_pte(new_page, vma->vm_page_prot);
2284 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2286 * Clear the pte entry and flush it first, before updating the
2287 * pte with the new entry. This will avoid a race condition
2288 * seen in the presence of one thread doing SMC and another
2291 ptep_clear_flush(vma, address, page_table);
2292 page_add_new_anon_rmap(new_page, vma, address);
2294 * We call the notify macro here because, when using secondary
2295 * mmu page tables (such as kvm shadow page tables), we want the
2296 * new page to be mapped directly into the secondary page table.
2298 set_pte_at_notify(mm, address, page_table, entry);
2299 update_mmu_cache(vma, address, page_table);
2302 * Only after switching the pte to the new page may
2303 * we remove the mapcount here. Otherwise another
2304 * process may come and find the rmap count decremented
2305 * before the pte is switched to the new page, and
2306 * "reuse" the old page writing into it while our pte
2307 * here still points into it and can be read by other
2310 * The critical issue is to order this
2311 * page_remove_rmap with the ptp_clear_flush above.
2312 * Those stores are ordered by (if nothing else,)
2313 * the barrier present in the atomic_add_negative
2314 * in page_remove_rmap.
2316 * Then the TLB flush in ptep_clear_flush ensures that
2317 * no process can access the old page before the
2318 * decremented mapcount is visible. And the old page
2319 * cannot be reused until after the decremented
2320 * mapcount is visible. So transitively, TLBs to
2321 * old page will be flushed before it can be reused.
2323 page_remove_rmap(old_page);
2326 /* Free the old page.. */
2327 new_page = old_page;
2328 ret |= VM_FAULT_WRITE;
2330 mem_cgroup_uncharge_page(new_page);
2333 page_cache_release(new_page);
2335 page_cache_release(old_page);
2337 pte_unmap_unlock(page_table, ptl);
2340 * Yes, Virginia, this is actually required to prevent a race
2341 * with clear_page_dirty_for_io() from clearing the page dirty
2342 * bit after it clear all dirty ptes, but before a racing
2343 * do_wp_page installs a dirty pte.
2345 * do_no_page is protected similarly.
2347 if (!page_mkwrite) {
2348 wait_on_page_locked(dirty_page);
2349 set_page_dirty_balance(dirty_page, page_mkwrite);
2351 put_page(dirty_page);
2353 struct address_space *mapping = dirty_page->mapping;
2355 set_page_dirty(dirty_page);
2356 unlock_page(dirty_page);
2357 page_cache_release(dirty_page);
2360 * Some device drivers do not set page.mapping
2361 * but still dirty their pages
2363 balance_dirty_pages_ratelimited(mapping);
2367 /* file_update_time outside page_lock */
2369 file_update_time(vma->vm_file);
2373 page_cache_release(new_page);
2377 unlock_page(old_page);
2378 page_cache_release(old_page);
2380 page_cache_release(old_page);
2382 return VM_FAULT_OOM;
2385 page_cache_release(old_page);
2390 * Helper functions for unmap_mapping_range().
2392 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2394 * We have to restart searching the prio_tree whenever we drop the lock,
2395 * since the iterator is only valid while the lock is held, and anyway
2396 * a later vma might be split and reinserted earlier while lock dropped.
2398 * The list of nonlinear vmas could be handled more efficiently, using
2399 * a placeholder, but handle it in the same way until a need is shown.
2400 * It is important to search the prio_tree before nonlinear list: a vma
2401 * may become nonlinear and be shifted from prio_tree to nonlinear list
2402 * while the lock is dropped; but never shifted from list to prio_tree.
2404 * In order to make forward progress despite restarting the search,
2405 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2406 * quickly skip it next time around. Since the prio_tree search only
2407 * shows us those vmas affected by unmapping the range in question, we
2408 * can't efficiently keep all vmas in step with mapping->truncate_count:
2409 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2410 * mapping->truncate_count and vma->vm_truncate_count are protected by
2413 * In order to make forward progress despite repeatedly restarting some
2414 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2415 * and restart from that address when we reach that vma again. It might
2416 * have been split or merged, shrunk or extended, but never shifted: so
2417 * restart_addr remains valid so long as it remains in the vma's range.
2418 * unmap_mapping_range forces truncate_count to leap over page-aligned
2419 * values so we can save vma's restart_addr in its truncate_count field.
2421 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2423 static void reset_vma_truncate_counts(struct address_space *mapping)
2425 struct vm_area_struct *vma;
2426 struct prio_tree_iter iter;
2428 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2429 vma->vm_truncate_count = 0;
2430 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2431 vma->vm_truncate_count = 0;
2434 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2435 unsigned long start_addr, unsigned long end_addr,
2436 struct zap_details *details)
2438 unsigned long restart_addr;
2442 * files that support invalidating or truncating portions of the
2443 * file from under mmaped areas must have their ->fault function
2444 * return a locked page (and set VM_FAULT_LOCKED in the return).
2445 * This provides synchronisation against concurrent unmapping here.
2449 restart_addr = vma->vm_truncate_count;
2450 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2451 start_addr = restart_addr;
2452 if (start_addr >= end_addr) {
2453 /* Top of vma has been split off since last time */
2454 vma->vm_truncate_count = details->truncate_count;
2459 restart_addr = zap_page_range(vma, start_addr,
2460 end_addr - start_addr, details);
2461 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
2463 if (restart_addr >= end_addr) {
2464 /* We have now completed this vma: mark it so */
2465 vma->vm_truncate_count = details->truncate_count;
2469 /* Note restart_addr in vma's truncate_count field */
2470 vma->vm_truncate_count = restart_addr;
2475 spin_unlock(details->i_mmap_lock);
2477 spin_lock(details->i_mmap_lock);
2481 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2482 struct zap_details *details)
2484 struct vm_area_struct *vma;
2485 struct prio_tree_iter iter;
2486 pgoff_t vba, vea, zba, zea;
2489 vma_prio_tree_foreach(vma, &iter, root,
2490 details->first_index, details->last_index) {
2491 /* Skip quickly over those we have already dealt with */
2492 if (vma->vm_truncate_count == details->truncate_count)
2495 vba = vma->vm_pgoff;
2496 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2497 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2498 zba = details->first_index;
2501 zea = details->last_index;
2505 if (unmap_mapping_range_vma(vma,
2506 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2507 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2513 static inline void unmap_mapping_range_list(struct list_head *head,
2514 struct zap_details *details)
2516 struct vm_area_struct *vma;
2519 * In nonlinear VMAs there is no correspondence between virtual address
2520 * offset and file offset. So we must perform an exhaustive search
2521 * across *all* the pages in each nonlinear VMA, not just the pages
2522 * whose virtual address lies outside the file truncation point.
2525 list_for_each_entry(vma, head, shared.vm_set.list) {
2526 /* Skip quickly over those we have already dealt with */
2527 if (vma->vm_truncate_count == details->truncate_count)
2529 details->nonlinear_vma = vma;
2530 if (unmap_mapping_range_vma(vma, vma->vm_start,
2531 vma->vm_end, details) < 0)
2537 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2538 * @mapping: the address space containing mmaps to be unmapped.
2539 * @holebegin: byte in first page to unmap, relative to the start of
2540 * the underlying file. This will be rounded down to a PAGE_SIZE
2541 * boundary. Note that this is different from truncate_pagecache(), which
2542 * must keep the partial page. In contrast, we must get rid of
2544 * @holelen: size of prospective hole in bytes. This will be rounded
2545 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2547 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2548 * but 0 when invalidating pagecache, don't throw away private data.
2550 void unmap_mapping_range(struct address_space *mapping,
2551 loff_t const holebegin, loff_t const holelen, int even_cows)
2553 struct zap_details details;
2554 pgoff_t hba = holebegin >> PAGE_SHIFT;
2555 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2557 /* Check for overflow. */
2558 if (sizeof(holelen) > sizeof(hlen)) {
2560 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2561 if (holeend & ~(long long)ULONG_MAX)
2562 hlen = ULONG_MAX - hba + 1;
2565 details.check_mapping = even_cows? NULL: mapping;
2566 details.nonlinear_vma = NULL;
2567 details.first_index = hba;
2568 details.last_index = hba + hlen - 1;
2569 if (details.last_index < details.first_index)
2570 details.last_index = ULONG_MAX;
2571 details.i_mmap_lock = &mapping->i_mmap_lock;
2573 spin_lock(&mapping->i_mmap_lock);
2575 /* Protect against endless unmapping loops */
2576 mapping->truncate_count++;
2577 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2578 if (mapping->truncate_count == 0)
2579 reset_vma_truncate_counts(mapping);
2580 mapping->truncate_count++;
2582 details.truncate_count = mapping->truncate_count;
2584 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2585 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2586 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2587 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2588 spin_unlock(&mapping->i_mmap_lock);
2590 EXPORT_SYMBOL(unmap_mapping_range);
2592 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2594 struct address_space *mapping = inode->i_mapping;
2597 * If the underlying filesystem is not going to provide
2598 * a way to truncate a range of blocks (punch a hole) -
2599 * we should return failure right now.
2601 if (!inode->i_op->truncate_range)
2604 mutex_lock(&inode->i_mutex);
2605 down_write(&inode->i_alloc_sem);
2606 unmap_mapping_range(mapping, offset, (end - offset), 1);
2607 truncate_inode_pages_range(mapping, offset, end);
2608 unmap_mapping_range(mapping, offset, (end - offset), 1);
2609 inode->i_op->truncate_range(inode, offset, end);
2610 up_write(&inode->i_alloc_sem);
2611 mutex_unlock(&inode->i_mutex);
2617 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2618 * but allow concurrent faults), and pte mapped but not yet locked.
2619 * We return with mmap_sem still held, but pte unmapped and unlocked.
2621 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2622 unsigned long address, pte_t *page_table, pmd_t *pmd,
2623 unsigned int flags, pte_t orig_pte)
2626 struct page *page, *swapcache = NULL;
2629 struct mem_cgroup *ptr = NULL;
2633 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2636 entry = pte_to_swp_entry(orig_pte);
2637 if (unlikely(non_swap_entry(entry))) {
2638 if (is_migration_entry(entry)) {
2639 migration_entry_wait(mm, pmd, address);
2640 } else if (is_hwpoison_entry(entry)) {
2641 ret = VM_FAULT_HWPOISON;
2643 print_bad_pte(vma, address, orig_pte, NULL);
2644 ret = VM_FAULT_SIGBUS;
2648 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2649 page = lookup_swap_cache(entry);
2651 grab_swap_token(mm); /* Contend for token _before_ read-in */
2652 page = swapin_readahead(entry,
2653 GFP_HIGHUSER_MOVABLE, vma, address);
2656 * Back out if somebody else faulted in this pte
2657 * while we released the pte lock.
2659 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2660 if (likely(pte_same(*page_table, orig_pte)))
2662 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2666 /* Had to read the page from swap area: Major fault */
2667 ret = VM_FAULT_MAJOR;
2668 count_vm_event(PGMAJFAULT);
2669 } else if (PageHWPoison(page)) {
2671 * hwpoisoned dirty swapcache pages are kept for killing
2672 * owner processes (which may be unknown at hwpoison time)
2674 ret = VM_FAULT_HWPOISON;
2675 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2680 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2683 * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
2684 * release the swapcache from under us. The page pin, and pte_same
2685 * test below, are not enough to exclude that. Even if it is still
2686 * swapcache, we need to check that the page's swap has not changed.
2688 if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
2691 if (ksm_might_need_to_copy(page, vma, address)) {
2693 page = ksm_does_need_to_copy(page, vma, address);
2695 if (unlikely(!page)) {
2703 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
2709 * Back out if somebody else already faulted in this pte.
2711 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2712 if (unlikely(!pte_same(*page_table, orig_pte)))
2715 if (unlikely(!PageUptodate(page))) {
2716 ret = VM_FAULT_SIGBUS;
2721 * The page isn't present yet, go ahead with the fault.
2723 * Be careful about the sequence of operations here.
2724 * To get its accounting right, reuse_swap_page() must be called
2725 * while the page is counted on swap but not yet in mapcount i.e.
2726 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2727 * must be called after the swap_free(), or it will never succeed.
2728 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2729 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2730 * in page->private. In this case, a record in swap_cgroup is silently
2731 * discarded at swap_free().
2734 inc_mm_counter_fast(mm, MM_ANONPAGES);
2735 dec_mm_counter_fast(mm, MM_SWAPENTS);
2736 pte = mk_pte(page, vma->vm_page_prot);
2737 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
2738 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2739 flags &= ~FAULT_FLAG_WRITE;
2740 ret |= VM_FAULT_WRITE;
2743 flush_icache_page(vma, page);
2744 set_pte_at(mm, address, page_table, pte);
2745 do_page_add_anon_rmap(page, vma, address, exclusive);
2746 /* It's better to call commit-charge after rmap is established */
2747 mem_cgroup_commit_charge_swapin(page, ptr);
2750 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
2751 try_to_free_swap(page);
2755 * Hold the lock to avoid the swap entry to be reused
2756 * until we take the PT lock for the pte_same() check
2757 * (to avoid false positives from pte_same). For
2758 * further safety release the lock after the swap_free
2759 * so that the swap count won't change under a
2760 * parallel locked swapcache.
2762 unlock_page(swapcache);
2763 page_cache_release(swapcache);
2766 if (flags & FAULT_FLAG_WRITE) {
2767 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2768 if (ret & VM_FAULT_ERROR)
2769 ret &= VM_FAULT_ERROR;
2773 /* No need to invalidate - it was non-present before */
2774 update_mmu_cache(vma, address, page_table);
2776 pte_unmap_unlock(page_table, ptl);
2780 mem_cgroup_cancel_charge_swapin(ptr);
2781 pte_unmap_unlock(page_table, ptl);
2785 page_cache_release(page);
2787 unlock_page(swapcache);
2788 page_cache_release(swapcache);
2794 * This is like a special single-page "expand_{down|up}wards()",
2795 * except we must first make sure that 'address{-|+}PAGE_SIZE'
2796 * doesn't hit another vma.
2798 static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
2800 address &= PAGE_MASK;
2801 if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
2802 struct vm_area_struct *prev = vma->vm_prev;
2805 * Is there a mapping abutting this one below?
2807 * That's only ok if it's the same stack mapping
2808 * that has gotten split..
2810 if (prev && prev->vm_end == address)
2811 return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
2813 expand_stack(vma, address - PAGE_SIZE);
2815 if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
2816 struct vm_area_struct *next = vma->vm_next;
2818 /* As VM_GROWSDOWN but s/below/above/ */
2819 if (next && next->vm_start == address + PAGE_SIZE)
2820 return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
2822 expand_upwards(vma, address + PAGE_SIZE);
2828 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2829 * but allow concurrent faults), and pte mapped but not yet locked.
2830 * We return with mmap_sem still held, but pte unmapped and unlocked.
2832 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2833 unsigned long address, pte_t *page_table, pmd_t *pmd,
2840 pte_unmap(page_table);
2842 /* Check if we need to add a guard page to the stack */
2843 if (check_stack_guard_page(vma, address) < 0)
2844 return VM_FAULT_SIGBUS;
2846 /* Use the zero-page for reads */
2847 if (!(flags & FAULT_FLAG_WRITE)) {
2848 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2849 vma->vm_page_prot));
2850 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2851 if (!pte_none(*page_table))
2856 /* Allocate our own private page. */
2857 if (unlikely(anon_vma_prepare(vma)))
2859 page = alloc_zeroed_user_highpage_movable(vma, address);
2862 __SetPageUptodate(page);
2864 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
2867 entry = mk_pte(page, vma->vm_page_prot);
2868 if (vma->vm_flags & VM_WRITE)
2869 entry = pte_mkwrite(pte_mkdirty(entry));
2871 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2872 if (!pte_none(*page_table))
2875 inc_mm_counter_fast(mm, MM_ANONPAGES);
2876 page_add_new_anon_rmap(page, vma, address);
2878 set_pte_at(mm, address, page_table, entry);
2880 /* No need to invalidate - it was non-present before */
2881 update_mmu_cache(vma, address, page_table);
2883 pte_unmap_unlock(page_table, ptl);
2886 mem_cgroup_uncharge_page(page);
2887 page_cache_release(page);
2890 page_cache_release(page);
2892 return VM_FAULT_OOM;
2896 * __do_fault() tries to create a new page mapping. It aggressively
2897 * tries to share with existing pages, but makes a separate copy if
2898 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2899 * the next page fault.
2901 * As this is called only for pages that do not currently exist, we
2902 * do not need to flush old virtual caches or the TLB.
2904 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2905 * but allow concurrent faults), and pte neither mapped nor locked.
2906 * We return with mmap_sem still held, but pte unmapped and unlocked.
2908 static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2909 unsigned long address, pmd_t *pmd,
2910 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2918 struct page *dirty_page = NULL;
2919 struct vm_fault vmf;
2921 int page_mkwrite = 0;
2923 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2928 ret = vma->vm_ops->fault(vma, &vmf);
2929 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2932 if (unlikely(PageHWPoison(vmf.page))) {
2933 if (ret & VM_FAULT_LOCKED)
2934 unlock_page(vmf.page);
2935 return VM_FAULT_HWPOISON;
2939 * For consistency in subsequent calls, make the faulted page always
2942 if (unlikely(!(ret & VM_FAULT_LOCKED)))
2943 lock_page(vmf.page);
2945 VM_BUG_ON(!PageLocked(vmf.page));
2948 * Should we do an early C-O-W break?
2951 if (flags & FAULT_FLAG_WRITE) {
2952 if (!(vma->vm_flags & VM_SHARED)) {
2954 if (unlikely(anon_vma_prepare(vma))) {
2958 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2964 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
2966 page_cache_release(page);
2971 * Don't let another task, with possibly unlocked vma,
2972 * keep the mlocked page.
2974 if (vma->vm_flags & VM_LOCKED)
2975 clear_page_mlock(vmf.page);
2976 copy_user_highpage(page, vmf.page, address, vma);
2977 __SetPageUptodate(page);
2980 * If the page will be shareable, see if the backing
2981 * address space wants to know that the page is about
2982 * to become writable
2984 if (vma->vm_ops->page_mkwrite) {
2988 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2989 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2991 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2993 goto unwritable_page;
2995 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2997 if (!page->mapping) {
2998 ret = 0; /* retry the fault */
3000 goto unwritable_page;
3003 VM_BUG_ON(!PageLocked(page));
3010 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3013 * This silly early PAGE_DIRTY setting removes a race
3014 * due to the bad i386 page protection. But it's valid
3015 * for other architectures too.
3017 * Note that if FAULT_FLAG_WRITE is set, we either now have
3018 * an exclusive copy of the page, or this is a shared mapping,
3019 * so we can make it writable and dirty to avoid having to
3020 * handle that later.
3022 /* Only go through if we didn't race with anybody else... */
3023 if (likely(pte_same(*page_table, orig_pte))) {
3024 flush_icache_page(vma, page);
3025 entry = mk_pte(page, vma->vm_page_prot);
3026 if (flags & FAULT_FLAG_WRITE)
3027 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
3029 inc_mm_counter_fast(mm, MM_ANONPAGES);
3030 page_add_new_anon_rmap(page, vma, address);
3032 inc_mm_counter_fast(mm, MM_FILEPAGES);
3033 page_add_file_rmap(page);
3034 if (flags & FAULT_FLAG_WRITE) {
3036 get_page(dirty_page);
3039 set_pte_at(mm, address, page_table, entry);
3041 /* no need to invalidate: a not-present page won't be cached */
3042 update_mmu_cache(vma, address, page_table);
3045 mem_cgroup_uncharge_page(page);
3047 page_cache_release(page);
3049 anon = 1; /* no anon but release faulted_page */
3052 pte_unmap_unlock(page_table, ptl);
3056 struct address_space *mapping = page->mapping;
3058 if (set_page_dirty(dirty_page))
3060 unlock_page(dirty_page);
3061 put_page(dirty_page);
3062 if (page_mkwrite && mapping) {
3064 * Some device drivers do not set page.mapping but still
3067 balance_dirty_pages_ratelimited(mapping);
3070 /* file_update_time outside page_lock */
3072 file_update_time(vma->vm_file);
3074 unlock_page(vmf.page);
3076 page_cache_release(vmf.page);
3082 page_cache_release(page);
3086 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3087 unsigned long address, pte_t *page_table, pmd_t *pmd,
3088 unsigned int flags, pte_t orig_pte)
3090 pgoff_t pgoff = (((address & PAGE_MASK)
3091 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3093 pte_unmap(page_table);
3094 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3098 * Fault of a previously existing named mapping. Repopulate the pte
3099 * from the encoded file_pte if possible. This enables swappable
3102 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3103 * but allow concurrent faults), and pte mapped but not yet locked.
3104 * We return with mmap_sem still held, but pte unmapped and unlocked.
3106 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3107 unsigned long address, pte_t *page_table, pmd_t *pmd,
3108 unsigned int flags, pte_t orig_pte)
3112 flags |= FAULT_FLAG_NONLINEAR;
3114 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3117 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3119 * Page table corrupted: show pte and kill process.
3121 print_bad_pte(vma, address, orig_pte, NULL);
3122 return VM_FAULT_SIGBUS;
3125 pgoff = pte_to_pgoff(orig_pte);
3126 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3130 * These routines also need to handle stuff like marking pages dirty
3131 * and/or accessed for architectures that don't do it in hardware (most
3132 * RISC architectures). The early dirtying is also good on the i386.
3134 * There is also a hook called "update_mmu_cache()" that architectures
3135 * with external mmu caches can use to update those (ie the Sparc or
3136 * PowerPC hashed page tables that act as extended TLBs).
3138 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3139 * but allow concurrent faults), and pte mapped but not yet locked.
3140 * We return with mmap_sem still held, but pte unmapped and unlocked.
3142 static inline int handle_pte_fault(struct mm_struct *mm,
3143 struct vm_area_struct *vma, unsigned long address,
3144 pte_t *pte, pmd_t *pmd, unsigned int flags)
3150 if (!pte_present(entry)) {
3151 if (pte_none(entry)) {
3153 if (likely(vma->vm_ops->fault))
3154 return do_linear_fault(mm, vma, address,
3155 pte, pmd, flags, entry);
3157 return do_anonymous_page(mm, vma, address,
3160 if (pte_file(entry))
3161 return do_nonlinear_fault(mm, vma, address,
3162 pte, pmd, flags, entry);
3163 return do_swap_page(mm, vma, address,
3164 pte, pmd, flags, entry);
3167 ptl = pte_lockptr(mm, pmd);
3169 if (unlikely(!pte_same(*pte, entry)))
3171 if (flags & FAULT_FLAG_WRITE) {
3172 if (!pte_write(entry))
3173 return do_wp_page(mm, vma, address,
3174 pte, pmd, ptl, entry);
3175 entry = pte_mkdirty(entry);
3177 entry = pte_mkyoung(entry);
3178 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3179 update_mmu_cache(vma, address, pte);
3182 * This is needed only for protection faults but the arch code
3183 * is not yet telling us if this is a protection fault or not.
3184 * This still avoids useless tlb flushes for .text page faults
3187 if (flags & FAULT_FLAG_WRITE)
3188 flush_tlb_fix_spurious_fault(vma, address);
3191 pte_unmap_unlock(pte, ptl);
3196 * By the time we get here, we already hold the mm semaphore
3198 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3199 unsigned long address, unsigned int flags)
3206 __set_current_state(TASK_RUNNING);
3208 count_vm_event(PGFAULT);
3210 /* do counter updates before entering really critical section. */
3211 check_sync_rss_stat(current);
3213 if (unlikely(is_vm_hugetlb_page(vma)))
3214 return hugetlb_fault(mm, vma, address, flags);
3216 pgd = pgd_offset(mm, address);
3217 pud = pud_alloc(mm, pgd, address);
3219 return VM_FAULT_OOM;
3220 pmd = pmd_alloc(mm, pud, address);
3222 return VM_FAULT_OOM;
3223 pte = pte_alloc_map(mm, pmd, address);
3225 return VM_FAULT_OOM;
3227 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3230 #ifndef __PAGETABLE_PUD_FOLDED
3232 * Allocate page upper directory.
3233 * We've already handled the fast-path in-line.
3235 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3237 pud_t *new = pud_alloc_one(mm, address);
3241 smp_wmb(); /* See comment in __pte_alloc */
3243 spin_lock(&mm->page_table_lock);
3244 if (pgd_present(*pgd)) /* Another has populated it */
3247 pgd_populate(mm, pgd, new);
3248 spin_unlock(&mm->page_table_lock);
3251 #endif /* __PAGETABLE_PUD_FOLDED */
3253 #ifndef __PAGETABLE_PMD_FOLDED
3255 * Allocate page middle directory.
3256 * We've already handled the fast-path in-line.
3258 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3260 pmd_t *new = pmd_alloc_one(mm, address);
3264 smp_wmb(); /* See comment in __pte_alloc */
3266 spin_lock(&mm->page_table_lock);
3267 #ifndef __ARCH_HAS_4LEVEL_HACK
3268 if (pud_present(*pud)) /* Another has populated it */
3271 pud_populate(mm, pud, new);
3273 if (pgd_present(*pud)) /* Another has populated it */
3276 pgd_populate(mm, pud, new);
3277 #endif /* __ARCH_HAS_4LEVEL_HACK */
3278 spin_unlock(&mm->page_table_lock);
3281 #endif /* __PAGETABLE_PMD_FOLDED */
3283 int make_pages_present(unsigned long addr, unsigned long end)
3285 int ret, len, write;
3286 struct vm_area_struct * vma;
3288 vma = find_vma(current->mm, addr);
3291 write = (vma->vm_flags & VM_WRITE) != 0;
3292 BUG_ON(addr >= end);
3293 BUG_ON(end > vma->vm_end);
3294 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
3295 ret = get_user_pages(current, current->mm, addr,
3296 len, write, 0, NULL, NULL);
3299 return ret == len ? 0 : -EFAULT;
3302 #if !defined(__HAVE_ARCH_GATE_AREA)
3304 #if defined(AT_SYSINFO_EHDR)
3305 static struct vm_area_struct gate_vma;
3307 static int __init gate_vma_init(void)
3309 gate_vma.vm_mm = NULL;
3310 gate_vma.vm_start = FIXADDR_USER_START;
3311 gate_vma.vm_end = FIXADDR_USER_END;
3312 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3313 gate_vma.vm_page_prot = __P101;
3315 * Make sure the vDSO gets into every core dump.
3316 * Dumping its contents makes post-mortem fully interpretable later
3317 * without matching up the same kernel and hardware config to see
3318 * what PC values meant.
3320 gate_vma.vm_flags |= VM_ALWAYSDUMP;
3323 __initcall(gate_vma_init);
3326 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
3328 #ifdef AT_SYSINFO_EHDR
3335 int in_gate_area_no_task(unsigned long addr)
3337 #ifdef AT_SYSINFO_EHDR
3338 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3344 #endif /* __HAVE_ARCH_GATE_AREA */
3346 static int follow_pte(struct mm_struct *mm, unsigned long address,
3347 pte_t **ptepp, spinlock_t **ptlp)
3354 pgd = pgd_offset(mm, address);
3355 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3358 pud = pud_offset(pgd, address);
3359 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3362 pmd = pmd_offset(pud, address);
3363 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3366 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3370 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3373 if (!pte_present(*ptep))
3378 pte_unmap_unlock(ptep, *ptlp);
3384 * follow_pfn - look up PFN at a user virtual address
3385 * @vma: memory mapping
3386 * @address: user virtual address
3387 * @pfn: location to store found PFN
3389 * Only IO mappings and raw PFN mappings are allowed.
3391 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3393 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3400 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3403 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3406 *pfn = pte_pfn(*ptep);
3407 pte_unmap_unlock(ptep, ptl);
3410 EXPORT_SYMBOL(follow_pfn);
3412 #ifdef CONFIG_HAVE_IOREMAP_PROT
3413 int follow_phys(struct vm_area_struct *vma,
3414 unsigned long address, unsigned int flags,
3415 unsigned long *prot, resource_size_t *phys)
3421 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3424 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
3428 if ((flags & FOLL_WRITE) && !pte_write(pte))
3431 *prot = pgprot_val(pte_pgprot(pte));
3432 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
3436 pte_unmap_unlock(ptep, ptl);
3441 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3442 void *buf, int len, int write)
3444 resource_size_t phys_addr;
3445 unsigned long prot = 0;
3446 void __iomem *maddr;
3447 int offset = addr & (PAGE_SIZE-1);
3449 if (follow_phys(vma, addr, write, &prot, &phys_addr))
3452 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3454 memcpy_toio(maddr + offset, buf, len);
3456 memcpy_fromio(buf, maddr + offset, len);
3464 * Access another process' address space.
3465 * Source/target buffer must be kernel space,
3466 * Do not walk the page table directly, use get_user_pages
3468 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
3470 struct mm_struct *mm;
3471 struct vm_area_struct *vma;
3472 void *old_buf = buf;
3474 mm = get_task_mm(tsk);
3478 down_read(&mm->mmap_sem);
3479 /* ignore errors, just check how much was successfully transferred */
3481 int bytes, ret, offset;
3483 struct page *page = NULL;
3485 ret = get_user_pages(tsk, mm, addr, 1,
3486 write, 1, &page, &vma);
3489 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3490 * we can access using slightly different code.
3492 #ifdef CONFIG_HAVE_IOREMAP_PROT
3493 vma = find_vma(mm, addr);
3496 if (vma->vm_ops && vma->vm_ops->access)
3497 ret = vma->vm_ops->access(vma, addr, buf,
3505 offset = addr & (PAGE_SIZE-1);
3506 if (bytes > PAGE_SIZE-offset)
3507 bytes = PAGE_SIZE-offset;
3511 copy_to_user_page(vma, page, addr,
3512 maddr + offset, buf, bytes);
3513 set_page_dirty_lock(page);
3515 copy_from_user_page(vma, page, addr,
3516 buf, maddr + offset, bytes);
3519 page_cache_release(page);
3525 up_read(&mm->mmap_sem);
3528 return buf - old_buf;
3532 * Print the name of a VMA.
3534 void print_vma_addr(char *prefix, unsigned long ip)
3536 struct mm_struct *mm = current->mm;
3537 struct vm_area_struct *vma;
3540 * Do not print if we are in atomic
3541 * contexts (in exception stacks, etc.):
3543 if (preempt_count())
3546 down_read(&mm->mmap_sem);
3547 vma = find_vma(mm, ip);
3548 if (vma && vma->vm_file) {
3549 struct file *f = vma->vm_file;
3550 char *buf = (char *)__get_free_page(GFP_KERNEL);
3554 p = d_path(&f->f_path, buf, PAGE_SIZE);
3557 s = strrchr(p, '/');
3560 printk("%s%s[%lx+%lx]", prefix, p,
3562 vma->vm_end - vma->vm_start);
3563 free_page((unsigned long)buf);
3566 up_read(¤t->mm->mmap_sem);
3569 #ifdef CONFIG_PROVE_LOCKING
3570 void might_fault(void)
3573 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3574 * holding the mmap_sem, this is safe because kernel memory doesn't
3575 * get paged out, therefore we'll never actually fault, and the
3576 * below annotations will generate false positives.
3578 if (segment_eq(get_fs(), KERNEL_DS))
3583 * it would be nicer only to annotate paths which are not under
3584 * pagefault_disable, however that requires a larger audit and
3585 * providing helpers like get_user_atomic.
3587 if (!in_atomic() && current->mm)
3588 might_lock_read(¤t->mm->mmap_sem);
3590 EXPORT_SYMBOL(might_fault);