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)
313 * The next few lines have given us lots of grief...
315 * Why are we testing PMD* at this top level? Because often
316 * there will be no work to do at all, and we'd prefer not to
317 * go all the way down to the bottom just to discover that.
319 * Why all these "- 1"s? Because 0 represents both the bottom
320 * of the address space and the top of it (using -1 for the
321 * top wouldn't help much: the masks would do the wrong thing).
322 * The rule is that addr 0 and floor 0 refer to the bottom of
323 * the address space, but end 0 and ceiling 0 refer to the top
324 * Comparisons need to use "end - 1" and "ceiling - 1" (though
325 * that end 0 case should be mythical).
327 * Wherever addr is brought up or ceiling brought down, we must
328 * be careful to reject "the opposite 0" before it confuses the
329 * subsequent tests. But what about where end is brought down
330 * by PMD_SIZE below? no, end can't go down to 0 there.
332 * Whereas we round start (addr) and ceiling down, by different
333 * masks at different levels, in order to test whether a table
334 * now has no other vmas using it, so can be freed, we don't
335 * bother to round floor or end up - the tests don't need that.
349 if (end - 1 > ceiling - 1)
355 pgd = pgd_offset(tlb->mm, addr);
357 next = pgd_addr_end(addr, end);
358 if (pgd_none_or_clear_bad(pgd))
360 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
361 } while (pgd++, addr = next, addr != end);
364 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
365 unsigned long floor, unsigned long ceiling)
368 struct vm_area_struct *next = vma->vm_next;
369 unsigned long addr = vma->vm_start;
372 * Hide vma from rmap and truncate_pagecache before freeing
375 unlink_anon_vmas(vma);
376 unlink_file_vma(vma);
378 if (is_vm_hugetlb_page(vma)) {
379 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
380 floor, next? next->vm_start: ceiling);
383 * Optimization: gather nearby vmas into one call down
385 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
386 && !is_vm_hugetlb_page(next)) {
389 unlink_anon_vmas(vma);
390 unlink_file_vma(vma);
392 free_pgd_range(tlb, addr, vma->vm_end,
393 floor, next? next->vm_start: ceiling);
399 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
401 pgtable_t new = pte_alloc_one(mm, address);
406 * Ensure all pte setup (eg. pte page lock and page clearing) are
407 * visible before the pte is made visible to other CPUs by being
408 * put into page tables.
410 * The other side of the story is the pointer chasing in the page
411 * table walking code (when walking the page table without locking;
412 * ie. most of the time). Fortunately, these data accesses consist
413 * of a chain of data-dependent loads, meaning most CPUs (alpha
414 * being the notable exception) will already guarantee loads are
415 * seen in-order. See the alpha page table accessors for the
416 * smp_read_barrier_depends() barriers in page table walking code.
418 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
420 spin_lock(&mm->page_table_lock);
421 if (!pmd_present(*pmd)) { /* Has another populated it ? */
423 pmd_populate(mm, pmd, new);
426 spin_unlock(&mm->page_table_lock);
432 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
434 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
438 smp_wmb(); /* See comment in __pte_alloc */
440 spin_lock(&init_mm.page_table_lock);
441 if (!pmd_present(*pmd)) { /* Has another populated it ? */
442 pmd_populate_kernel(&init_mm, pmd, new);
445 spin_unlock(&init_mm.page_table_lock);
447 pte_free_kernel(&init_mm, new);
451 static inline void init_rss_vec(int *rss)
453 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
456 static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
460 if (current->mm == mm)
461 sync_mm_rss(current, mm);
462 for (i = 0; i < NR_MM_COUNTERS; i++)
464 add_mm_counter(mm, i, rss[i]);
468 * This function is called to print an error when a bad pte
469 * is found. For example, we might have a PFN-mapped pte in
470 * a region that doesn't allow it.
472 * The calling function must still handle the error.
474 static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
475 pte_t pte, struct page *page)
477 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
478 pud_t *pud = pud_offset(pgd, addr);
479 pmd_t *pmd = pmd_offset(pud, addr);
480 struct address_space *mapping;
482 static unsigned long resume;
483 static unsigned long nr_shown;
484 static unsigned long nr_unshown;
487 * Allow a burst of 60 reports, then keep quiet for that minute;
488 * or allow a steady drip of one report per second.
490 if (nr_shown == 60) {
491 if (time_before(jiffies, resume)) {
497 "BUG: Bad page map: %lu messages suppressed\n",
504 resume = jiffies + 60 * HZ;
506 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
507 index = linear_page_index(vma, addr);
510 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
512 (long long)pte_val(pte), (long long)pmd_val(*pmd));
516 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
517 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
519 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
522 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
523 (unsigned long)vma->vm_ops->fault);
524 if (vma->vm_file && vma->vm_file->f_op)
525 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
526 (unsigned long)vma->vm_file->f_op->mmap);
528 add_taint(TAINT_BAD_PAGE);
531 static inline int is_cow_mapping(unsigned int flags)
533 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
537 static inline int is_zero_pfn(unsigned long pfn)
539 return pfn == zero_pfn;
544 static inline unsigned long my_zero_pfn(unsigned long addr)
551 * vm_normal_page -- This function gets the "struct page" associated with a pte.
553 * "Special" mappings do not wish to be associated with a "struct page" (either
554 * it doesn't exist, or it exists but they don't want to touch it). In this
555 * case, NULL is returned here. "Normal" mappings do have a struct page.
557 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
558 * pte bit, in which case this function is trivial. Secondly, an architecture
559 * may not have a spare pte bit, which requires a more complicated scheme,
562 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
563 * special mapping (even if there are underlying and valid "struct pages").
564 * COWed pages of a VM_PFNMAP are always normal.
566 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
567 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
568 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
569 * mapping will always honor the rule
571 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
573 * And for normal mappings this is false.
575 * This restricts such mappings to be a linear translation from virtual address
576 * to pfn. To get around this restriction, we allow arbitrary mappings so long
577 * as the vma is not a COW mapping; in that case, we know that all ptes are
578 * special (because none can have been COWed).
581 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
583 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
584 * page" backing, however the difference is that _all_ pages with a struct
585 * page (that is, those where pfn_valid is true) are refcounted and considered
586 * normal pages by the VM. The disadvantage is that pages are refcounted
587 * (which can be slower and simply not an option for some PFNMAP users). The
588 * advantage is that we don't have to follow the strict linearity rule of
589 * PFNMAP mappings in order to support COWable mappings.
592 #ifdef __HAVE_ARCH_PTE_SPECIAL
593 # define HAVE_PTE_SPECIAL 1
595 # define HAVE_PTE_SPECIAL 0
597 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
600 unsigned long pfn = pte_pfn(pte);
602 if (HAVE_PTE_SPECIAL) {
603 if (likely(!pte_special(pte)))
605 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
607 if (!is_zero_pfn(pfn))
608 print_bad_pte(vma, addr, pte, NULL);
612 /* !HAVE_PTE_SPECIAL case follows: */
614 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
615 if (vma->vm_flags & VM_MIXEDMAP) {
621 off = (addr - vma->vm_start) >> PAGE_SHIFT;
622 if (pfn == vma->vm_pgoff + off)
624 if (!is_cow_mapping(vma->vm_flags))
629 if (is_zero_pfn(pfn))
632 if (unlikely(pfn > highest_memmap_pfn)) {
633 print_bad_pte(vma, addr, pte, NULL);
638 * NOTE! We still have PageReserved() pages in the page tables.
639 * eg. VDSO mappings can cause them to exist.
642 return pfn_to_page(pfn);
646 * copy one vm_area from one task to the other. Assumes the page tables
647 * already present in the new task to be cleared in the whole range
648 * covered by this vma.
651 static inline unsigned long
652 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
653 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
654 unsigned long addr, int *rss)
656 unsigned long vm_flags = vma->vm_flags;
657 pte_t pte = *src_pte;
660 /* pte contains position in swap or file, so copy. */
661 if (unlikely(!pte_present(pte))) {
662 if (!pte_file(pte)) {
663 swp_entry_t entry = pte_to_swp_entry(pte);
665 if (swap_duplicate(entry) < 0)
668 /* make sure dst_mm is on swapoff's mmlist. */
669 if (unlikely(list_empty(&dst_mm->mmlist))) {
670 spin_lock(&mmlist_lock);
671 if (list_empty(&dst_mm->mmlist))
672 list_add(&dst_mm->mmlist,
674 spin_unlock(&mmlist_lock);
676 if (likely(!non_swap_entry(entry)))
678 else if (is_write_migration_entry(entry) &&
679 is_cow_mapping(vm_flags)) {
681 * COW mappings require pages in both parent
682 * and child to be set to read.
684 make_migration_entry_read(&entry);
685 pte = swp_entry_to_pte(entry);
686 set_pte_at(src_mm, addr, src_pte, pte);
693 * If it's a COW mapping, write protect it both
694 * in the parent and the child
696 if (is_cow_mapping(vm_flags)) {
697 ptep_set_wrprotect(src_mm, addr, src_pte);
698 pte = pte_wrprotect(pte);
702 * If it's a shared mapping, mark it clean in
705 if (vm_flags & VM_SHARED)
706 pte = pte_mkclean(pte);
707 pte = pte_mkold(pte);
709 page = vm_normal_page(vma, addr, pte);
720 set_pte_at(dst_mm, addr, dst_pte, pte);
724 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
725 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
726 unsigned long addr, unsigned long end)
728 pte_t *orig_src_pte, *orig_dst_pte;
729 pte_t *src_pte, *dst_pte;
730 spinlock_t *src_ptl, *dst_ptl;
732 int rss[NR_MM_COUNTERS];
733 swp_entry_t entry = (swp_entry_t){0};
738 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
741 src_pte = pte_offset_map_nested(src_pmd, addr);
742 src_ptl = pte_lockptr(src_mm, src_pmd);
743 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
744 orig_src_pte = src_pte;
745 orig_dst_pte = dst_pte;
746 arch_enter_lazy_mmu_mode();
750 * We are holding two locks at this point - either of them
751 * could generate latencies in another task on another CPU.
753 if (progress >= 32) {
755 if (need_resched() ||
756 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
759 if (pte_none(*src_pte)) {
763 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
768 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
770 arch_leave_lazy_mmu_mode();
771 spin_unlock(src_ptl);
772 pte_unmap_nested(orig_src_pte);
773 add_mm_rss_vec(dst_mm, rss);
774 pte_unmap_unlock(orig_dst_pte, dst_ptl);
778 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
787 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
788 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
789 unsigned long addr, unsigned long end)
791 pmd_t *src_pmd, *dst_pmd;
794 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
797 src_pmd = pmd_offset(src_pud, addr);
799 next = pmd_addr_end(addr, end);
800 if (pmd_none_or_clear_bad(src_pmd))
802 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
805 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
809 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
810 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
811 unsigned long addr, unsigned long end)
813 pud_t *src_pud, *dst_pud;
816 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
819 src_pud = pud_offset(src_pgd, addr);
821 next = pud_addr_end(addr, end);
822 if (pud_none_or_clear_bad(src_pud))
824 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
827 } while (dst_pud++, src_pud++, addr = next, addr != end);
831 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
832 struct vm_area_struct *vma)
834 pgd_t *src_pgd, *dst_pgd;
836 unsigned long addr = vma->vm_start;
837 unsigned long end = vma->vm_end;
841 * Don't copy ptes where a page fault will fill them correctly.
842 * Fork becomes much lighter when there are big shared or private
843 * readonly mappings. The tradeoff is that copy_page_range is more
844 * efficient than faulting.
846 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
851 if (is_vm_hugetlb_page(vma))
852 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
854 if (unlikely(is_pfn_mapping(vma))) {
856 * We do not free on error cases below as remove_vma
857 * gets called on error from higher level routine
859 ret = track_pfn_vma_copy(vma);
865 * We need to invalidate the secondary MMU mappings only when
866 * there could be a permission downgrade on the ptes of the
867 * parent mm. And a permission downgrade will only happen if
868 * is_cow_mapping() returns true.
870 if (is_cow_mapping(vma->vm_flags))
871 mmu_notifier_invalidate_range_start(src_mm, addr, end);
874 dst_pgd = pgd_offset(dst_mm, addr);
875 src_pgd = pgd_offset(src_mm, addr);
877 next = pgd_addr_end(addr, end);
878 if (pgd_none_or_clear_bad(src_pgd))
880 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
885 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
887 if (is_cow_mapping(vma->vm_flags))
888 mmu_notifier_invalidate_range_end(src_mm,
893 static unsigned long zap_pte_range(struct mmu_gather *tlb,
894 struct vm_area_struct *vma, pmd_t *pmd,
895 unsigned long addr, unsigned long end,
896 long *zap_work, struct zap_details *details)
898 struct mm_struct *mm = tlb->mm;
901 int rss[NR_MM_COUNTERS];
905 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
906 arch_enter_lazy_mmu_mode();
909 if (pte_none(ptent)) {
914 (*zap_work) -= PAGE_SIZE;
916 if (pte_present(ptent)) {
919 page = vm_normal_page(vma, addr, ptent);
920 if (unlikely(details) && page) {
922 * unmap_shared_mapping_pages() wants to
923 * invalidate cache without truncating:
924 * unmap shared but keep private pages.
926 if (details->check_mapping &&
927 details->check_mapping != page->mapping)
930 * Each page->index must be checked when
931 * invalidating or truncating nonlinear.
933 if (details->nonlinear_vma &&
934 (page->index < details->first_index ||
935 page->index > details->last_index))
938 ptent = ptep_get_and_clear_full(mm, addr, pte,
940 tlb_remove_tlb_entry(tlb, pte, addr);
943 if (unlikely(details) && details->nonlinear_vma
944 && linear_page_index(details->nonlinear_vma,
945 addr) != page->index)
946 set_pte_at(mm, addr, pte,
947 pgoff_to_pte(page->index));
951 if (pte_dirty(ptent))
952 set_page_dirty(page);
953 if (pte_young(ptent) &&
954 likely(!VM_SequentialReadHint(vma)))
955 mark_page_accessed(page);
958 page_remove_rmap(page);
959 if (unlikely(page_mapcount(page) < 0))
960 print_bad_pte(vma, addr, ptent, page);
961 tlb_remove_page(tlb, page);
965 * If details->check_mapping, we leave swap entries;
966 * if details->nonlinear_vma, we leave file entries.
968 if (unlikely(details))
970 if (pte_file(ptent)) {
971 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
972 print_bad_pte(vma, addr, ptent, NULL);
974 swp_entry_t entry = pte_to_swp_entry(ptent);
976 if (!non_swap_entry(entry))
978 if (unlikely(!free_swap_and_cache(entry)))
979 print_bad_pte(vma, addr, ptent, NULL);
981 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
982 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
984 add_mm_rss_vec(mm, rss);
985 arch_leave_lazy_mmu_mode();
986 pte_unmap_unlock(pte - 1, ptl);
991 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
992 struct vm_area_struct *vma, pud_t *pud,
993 unsigned long addr, unsigned long end,
994 long *zap_work, struct zap_details *details)
999 pmd = pmd_offset(pud, addr);
1001 next = pmd_addr_end(addr, end);
1002 if (pmd_none_or_clear_bad(pmd)) {
1006 next = zap_pte_range(tlb, vma, pmd, addr, next,
1008 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
1013 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1014 struct vm_area_struct *vma, pgd_t *pgd,
1015 unsigned long addr, unsigned long end,
1016 long *zap_work, struct zap_details *details)
1021 pud = pud_offset(pgd, addr);
1023 next = pud_addr_end(addr, end);
1024 if (pud_none_or_clear_bad(pud)) {
1028 next = zap_pmd_range(tlb, vma, pud, addr, next,
1030 } while (pud++, addr = next, (addr != end && *zap_work > 0));
1035 static unsigned long unmap_page_range(struct mmu_gather *tlb,
1036 struct vm_area_struct *vma,
1037 unsigned long addr, unsigned long end,
1038 long *zap_work, struct zap_details *details)
1043 if (details && !details->check_mapping && !details->nonlinear_vma)
1046 BUG_ON(addr >= end);
1047 mem_cgroup_uncharge_start();
1048 tlb_start_vma(tlb, vma);
1049 pgd = pgd_offset(vma->vm_mm, addr);
1051 next = pgd_addr_end(addr, end);
1052 if (pgd_none_or_clear_bad(pgd)) {
1056 next = zap_pud_range(tlb, vma, pgd, addr, next,
1058 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
1059 tlb_end_vma(tlb, vma);
1060 mem_cgroup_uncharge_end();
1065 #ifdef CONFIG_PREEMPT
1066 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
1068 /* No preempt: go for improved straight-line efficiency */
1069 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
1073 * unmap_vmas - unmap a range of memory covered by a list of vma's
1074 * @tlbp: address of the caller's struct mmu_gather
1075 * @vma: the starting vma
1076 * @start_addr: virtual address at which to start unmapping
1077 * @end_addr: virtual address at which to end unmapping
1078 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
1079 * @details: details of nonlinear truncation or shared cache invalidation
1081 * Returns the end address of the unmapping (restart addr if interrupted).
1083 * Unmap all pages in the vma list.
1085 * We aim to not hold locks for too long (for scheduling latency reasons).
1086 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
1087 * return the ending mmu_gather to the caller.
1089 * Only addresses between `start' and `end' will be unmapped.
1091 * The VMA list must be sorted in ascending virtual address order.
1093 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1094 * range after unmap_vmas() returns. So the only responsibility here is to
1095 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1096 * drops the lock and schedules.
1098 unsigned long unmap_vmas(struct mmu_gather **tlbp,
1099 struct vm_area_struct *vma, unsigned long start_addr,
1100 unsigned long end_addr, unsigned long *nr_accounted,
1101 struct zap_details *details)
1103 long zap_work = ZAP_BLOCK_SIZE;
1104 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
1105 int tlb_start_valid = 0;
1106 unsigned long start = start_addr;
1107 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
1108 int fullmm = (*tlbp)->fullmm;
1109 struct mm_struct *mm = vma->vm_mm;
1111 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1112 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
1115 start = max(vma->vm_start, start_addr);
1116 if (start >= vma->vm_end)
1118 end = min(vma->vm_end, end_addr);
1119 if (end <= vma->vm_start)
1122 if (vma->vm_flags & VM_ACCOUNT)
1123 *nr_accounted += (end - start) >> PAGE_SHIFT;
1125 if (unlikely(is_pfn_mapping(vma)))
1126 untrack_pfn_vma(vma, 0, 0);
1128 while (start != end) {
1129 if (!tlb_start_valid) {
1131 tlb_start_valid = 1;
1134 if (unlikely(is_vm_hugetlb_page(vma))) {
1136 * It is undesirable to test vma->vm_file as it
1137 * should be non-null for valid hugetlb area.
1138 * However, vm_file will be NULL in the error
1139 * cleanup path of do_mmap_pgoff. When
1140 * hugetlbfs ->mmap method fails,
1141 * do_mmap_pgoff() nullifies vma->vm_file
1142 * before calling this function to clean up.
1143 * Since no pte has actually been setup, it is
1144 * safe to do nothing in this case.
1147 unmap_hugepage_range(vma, start, end, NULL);
1148 zap_work -= (end - start) /
1149 pages_per_huge_page(hstate_vma(vma));
1154 start = unmap_page_range(*tlbp, vma,
1155 start, end, &zap_work, details);
1158 BUG_ON(start != end);
1162 tlb_finish_mmu(*tlbp, tlb_start, start);
1164 if (need_resched() ||
1165 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
1173 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
1174 tlb_start_valid = 0;
1175 zap_work = ZAP_BLOCK_SIZE;
1179 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1180 return start; /* which is now the end (or restart) address */
1184 * zap_page_range - remove user pages in a given range
1185 * @vma: vm_area_struct holding the applicable pages
1186 * @address: starting address of pages to zap
1187 * @size: number of bytes to zap
1188 * @details: details of nonlinear truncation or shared cache invalidation
1190 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
1191 unsigned long size, struct zap_details *details)
1193 struct mm_struct *mm = vma->vm_mm;
1194 struct mmu_gather *tlb;
1195 unsigned long end = address + size;
1196 unsigned long nr_accounted = 0;
1199 tlb = tlb_gather_mmu(mm, 0);
1200 update_hiwater_rss(mm);
1201 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
1203 tlb_finish_mmu(tlb, address, end);
1208 * zap_vma_ptes - remove ptes mapping the vma
1209 * @vma: vm_area_struct holding ptes to be zapped
1210 * @address: starting address of pages to zap
1211 * @size: number of bytes to zap
1213 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1215 * The entire address range must be fully contained within the vma.
1217 * Returns 0 if successful.
1219 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1222 if (address < vma->vm_start || address + size > vma->vm_end ||
1223 !(vma->vm_flags & VM_PFNMAP))
1225 zap_page_range(vma, address, size, NULL);
1228 EXPORT_SYMBOL_GPL(zap_vma_ptes);
1231 * Do a quick page-table lookup for a single page.
1233 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1242 struct mm_struct *mm = vma->vm_mm;
1244 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1245 if (!IS_ERR(page)) {
1246 BUG_ON(flags & FOLL_GET);
1251 pgd = pgd_offset(mm, address);
1252 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1255 pud = pud_offset(pgd, address);
1258 if (pud_huge(*pud)) {
1259 BUG_ON(flags & FOLL_GET);
1260 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1263 if (unlikely(pud_bad(*pud)))
1266 pmd = pmd_offset(pud, address);
1269 if (pmd_huge(*pmd)) {
1270 BUG_ON(flags & FOLL_GET);
1271 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1274 if (unlikely(pmd_bad(*pmd)))
1277 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1280 if (!pte_present(pte))
1282 if ((flags & FOLL_WRITE) && !pte_write(pte))
1285 page = vm_normal_page(vma, address, pte);
1286 if (unlikely(!page)) {
1287 if ((flags & FOLL_DUMP) ||
1288 !is_zero_pfn(pte_pfn(pte)))
1290 page = pte_page(pte);
1293 if (flags & FOLL_GET)
1295 if (flags & FOLL_TOUCH) {
1296 if ((flags & FOLL_WRITE) &&
1297 !pte_dirty(pte) && !PageDirty(page))
1298 set_page_dirty(page);
1300 * pte_mkyoung() would be more correct here, but atomic care
1301 * is needed to avoid losing the dirty bit: it is easier to use
1302 * mark_page_accessed().
1304 mark_page_accessed(page);
1307 pte_unmap_unlock(ptep, ptl);
1312 pte_unmap_unlock(ptep, ptl);
1313 return ERR_PTR(-EFAULT);
1316 pte_unmap_unlock(ptep, ptl);
1322 * When core dumping an enormous anonymous area that nobody
1323 * has touched so far, we don't want to allocate unnecessary pages or
1324 * page tables. Return error instead of NULL to skip handle_mm_fault,
1325 * then get_dump_page() will return NULL to leave a hole in the dump.
1326 * But we can only make this optimization where a hole would surely
1327 * be zero-filled if handle_mm_fault() actually did handle it.
1329 if ((flags & FOLL_DUMP) &&
1330 (!vma->vm_ops || !vma->vm_ops->fault))
1331 return ERR_PTR(-EFAULT);
1335 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1336 unsigned long start, int nr_pages, unsigned int gup_flags,
1337 struct page **pages, struct vm_area_struct **vmas)
1340 unsigned long vm_flags;
1345 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1348 * Require read or write permissions.
1349 * If FOLL_FORCE is set, we only require the "MAY" flags.
1351 vm_flags = (gup_flags & FOLL_WRITE) ?
1352 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1353 vm_flags &= (gup_flags & FOLL_FORCE) ?
1354 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1358 struct vm_area_struct *vma;
1360 vma = find_extend_vma(mm, start);
1361 if (!vma && in_gate_area(tsk, start)) {
1362 unsigned long pg = start & PAGE_MASK;
1363 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1369 /* user gate pages are read-only */
1370 if (gup_flags & FOLL_WRITE)
1371 return i ? : -EFAULT;
1373 pgd = pgd_offset_k(pg);
1375 pgd = pgd_offset_gate(mm, pg);
1376 BUG_ON(pgd_none(*pgd));
1377 pud = pud_offset(pgd, pg);
1378 BUG_ON(pud_none(*pud));
1379 pmd = pmd_offset(pud, pg);
1381 return i ? : -EFAULT;
1382 pte = pte_offset_map(pmd, pg);
1383 if (pte_none(*pte)) {
1385 return i ? : -EFAULT;
1388 struct page *page = vm_normal_page(gate_vma, start, *pte);
1403 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1404 !(vm_flags & vma->vm_flags))
1405 return i ? : -EFAULT;
1407 if (is_vm_hugetlb_page(vma)) {
1408 i = follow_hugetlb_page(mm, vma, pages, vmas,
1409 &start, &nr_pages, i, gup_flags);
1415 unsigned int foll_flags = gup_flags;
1418 * If we have a pending SIGKILL, don't keep faulting
1419 * pages and potentially allocating memory.
1421 if (unlikely(fatal_signal_pending(current)))
1422 return i ? i : -ERESTARTSYS;
1425 while (!(page = follow_page(vma, start, foll_flags))) {
1428 ret = handle_mm_fault(mm, vma, start,
1429 (foll_flags & FOLL_WRITE) ?
1430 FAULT_FLAG_WRITE : 0);
1432 if (ret & VM_FAULT_ERROR) {
1433 if (ret & VM_FAULT_OOM)
1434 return i ? i : -ENOMEM;
1436 (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
1437 return i ? i : -EFAULT;
1440 if (ret & VM_FAULT_MAJOR)
1446 * The VM_FAULT_WRITE bit tells us that
1447 * do_wp_page has broken COW when necessary,
1448 * even if maybe_mkwrite decided not to set
1449 * pte_write. We can thus safely do subsequent
1450 * page lookups as if they were reads. But only
1451 * do so when looping for pte_write is futile:
1452 * in some cases userspace may also be wanting
1453 * to write to the gotten user page, which a
1454 * read fault here might prevent (a readonly
1455 * page might get reCOWed by userspace write).
1457 if ((ret & VM_FAULT_WRITE) &&
1458 !(vma->vm_flags & VM_WRITE))
1459 foll_flags &= ~FOLL_WRITE;
1464 return i ? i : PTR_ERR(page);
1468 flush_anon_page(vma, page, start);
1469 flush_dcache_page(page);
1476 } while (nr_pages && start < vma->vm_end);
1482 * get_user_pages() - pin user pages in memory
1483 * @tsk: task_struct of target task
1484 * @mm: mm_struct of target mm
1485 * @start: starting user address
1486 * @nr_pages: number of pages from start to pin
1487 * @write: whether pages will be written to by the caller
1488 * @force: whether to force write access even if user mapping is
1489 * readonly. This will result in the page being COWed even
1490 * in MAP_SHARED mappings. You do not want this.
1491 * @pages: array that receives pointers to the pages pinned.
1492 * Should be at least nr_pages long. Or NULL, if caller
1493 * only intends to ensure the pages are faulted in.
1494 * @vmas: array of pointers to vmas corresponding to each page.
1495 * Or NULL if the caller does not require them.
1497 * Returns number of pages pinned. This may be fewer than the number
1498 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1499 * were pinned, returns -errno. Each page returned must be released
1500 * with a put_page() call when it is finished with. vmas will only
1501 * remain valid while mmap_sem is held.
1503 * Must be called with mmap_sem held for read or write.
1505 * get_user_pages walks a process's page tables and takes a reference to
1506 * each struct page that each user address corresponds to at a given
1507 * instant. That is, it takes the page that would be accessed if a user
1508 * thread accesses the given user virtual address at that instant.
1510 * This does not guarantee that the page exists in the user mappings when
1511 * get_user_pages returns, and there may even be a completely different
1512 * page there in some cases (eg. if mmapped pagecache has been invalidated
1513 * and subsequently re faulted). However it does guarantee that the page
1514 * won't be freed completely. And mostly callers simply care that the page
1515 * contains data that was valid *at some point in time*. Typically, an IO
1516 * or similar operation cannot guarantee anything stronger anyway because
1517 * locks can't be held over the syscall boundary.
1519 * If write=0, the page must not be written to. If the page is written to,
1520 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1521 * after the page is finished with, and before put_page is called.
1523 * get_user_pages is typically used for fewer-copy IO operations, to get a
1524 * handle on the memory by some means other than accesses via the user virtual
1525 * addresses. The pages may be submitted for DMA to devices or accessed via
1526 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1527 * use the correct cache flushing APIs.
1529 * See also get_user_pages_fast, for performance critical applications.
1531 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1532 unsigned long start, int nr_pages, int write, int force,
1533 struct page **pages, struct vm_area_struct **vmas)
1535 int flags = FOLL_TOUCH;
1540 flags |= FOLL_WRITE;
1542 flags |= FOLL_FORCE;
1544 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
1546 EXPORT_SYMBOL(get_user_pages);
1549 * get_dump_page() - pin user page in memory while writing it to core dump
1550 * @addr: user address
1552 * Returns struct page pointer of user page pinned for dump,
1553 * to be freed afterwards by page_cache_release() or put_page().
1555 * Returns NULL on any kind of failure - a hole must then be inserted into
1556 * the corefile, to preserve alignment with its headers; and also returns
1557 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
1558 * allowing a hole to be left in the corefile to save diskspace.
1560 * Called without mmap_sem, but after all other threads have been killed.
1562 #ifdef CONFIG_ELF_CORE
1563 struct page *get_dump_page(unsigned long addr)
1565 struct vm_area_struct *vma;
1568 if (__get_user_pages(current, current->mm, addr, 1,
1569 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
1571 flush_cache_page(vma, addr, page_to_pfn(page));
1574 #endif /* CONFIG_ELF_CORE */
1576 pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1579 pgd_t * pgd = pgd_offset(mm, addr);
1580 pud_t * pud = pud_alloc(mm, pgd, addr);
1582 pmd_t * pmd = pmd_alloc(mm, pud, addr);
1584 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1590 * This is the old fallback for page remapping.
1592 * For historical reasons, it only allows reserved pages. Only
1593 * old drivers should use this, and they needed to mark their
1594 * pages reserved for the old functions anyway.
1596 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1597 struct page *page, pgprot_t prot)
1599 struct mm_struct *mm = vma->vm_mm;
1608 flush_dcache_page(page);
1609 pte = get_locked_pte(mm, addr, &ptl);
1613 if (!pte_none(*pte))
1616 /* Ok, finally just insert the thing.. */
1618 inc_mm_counter_fast(mm, MM_FILEPAGES);
1619 page_add_file_rmap(page);
1620 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1623 pte_unmap_unlock(pte, ptl);
1626 pte_unmap_unlock(pte, ptl);
1632 * vm_insert_page - insert single page into user vma
1633 * @vma: user vma to map to
1634 * @addr: target user address of this page
1635 * @page: source kernel page
1637 * This allows drivers to insert individual pages they've allocated
1640 * The page has to be a nice clean _individual_ kernel allocation.
1641 * If you allocate a compound page, you need to have marked it as
1642 * such (__GFP_COMP), or manually just split the page up yourself
1643 * (see split_page()).
1645 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1646 * took an arbitrary page protection parameter. This doesn't allow
1647 * that. Your vma protection will have to be set up correctly, which
1648 * means that if you want a shared writable mapping, you'd better
1649 * ask for a shared writable mapping!
1651 * The page does not need to be reserved.
1653 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1656 if (addr < vma->vm_start || addr >= vma->vm_end)
1658 if (!page_count(page))
1660 vma->vm_flags |= VM_INSERTPAGE;
1661 return insert_page(vma, addr, page, vma->vm_page_prot);
1663 EXPORT_SYMBOL(vm_insert_page);
1665 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1666 unsigned long pfn, pgprot_t prot)
1668 struct mm_struct *mm = vma->vm_mm;
1674 pte = get_locked_pte(mm, addr, &ptl);
1678 if (!pte_none(*pte))
1681 /* Ok, finally just insert the thing.. */
1682 entry = pte_mkspecial(pfn_pte(pfn, prot));
1683 set_pte_at(mm, addr, pte, entry);
1684 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
1688 pte_unmap_unlock(pte, ptl);
1694 * vm_insert_pfn - insert single pfn into user vma
1695 * @vma: user vma to map to
1696 * @addr: target user address of this page
1697 * @pfn: source kernel pfn
1699 * Similar to vm_inert_page, this allows drivers to insert individual pages
1700 * they've allocated into a user vma. Same comments apply.
1702 * This function should only be called from a vm_ops->fault handler, and
1703 * in that case the handler should return NULL.
1705 * vma cannot be a COW mapping.
1707 * As this is called only for pages that do not currently exist, we
1708 * do not need to flush old virtual caches or the TLB.
1710 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1714 pgprot_t pgprot = vma->vm_page_prot;
1716 * Technically, architectures with pte_special can avoid all these
1717 * restrictions (same for remap_pfn_range). However we would like
1718 * consistency in testing and feature parity among all, so we should
1719 * try to keep these invariants in place for everybody.
1721 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1722 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1723 (VM_PFNMAP|VM_MIXEDMAP));
1724 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1725 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
1727 if (addr < vma->vm_start || addr >= vma->vm_end)
1729 if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
1732 ret = insert_pfn(vma, addr, pfn, pgprot);
1735 untrack_pfn_vma(vma, pfn, PAGE_SIZE);
1739 EXPORT_SYMBOL(vm_insert_pfn);
1741 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1744 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1746 if (addr < vma->vm_start || addr >= vma->vm_end)
1750 * If we don't have pte special, then we have to use the pfn_valid()
1751 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1752 * refcount the page if pfn_valid is true (hence insert_page rather
1753 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1754 * without pte special, it would there be refcounted as a normal page.
1756 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1759 page = pfn_to_page(pfn);
1760 return insert_page(vma, addr, page, vma->vm_page_prot);
1762 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1764 EXPORT_SYMBOL(vm_insert_mixed);
1767 * maps a range of physical memory into the requested pages. the old
1768 * mappings are removed. any references to nonexistent pages results
1769 * in null mappings (currently treated as "copy-on-access")
1771 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1772 unsigned long addr, unsigned long end,
1773 unsigned long pfn, pgprot_t prot)
1778 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
1781 arch_enter_lazy_mmu_mode();
1783 BUG_ON(!pte_none(*pte));
1784 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
1786 } while (pte++, addr += PAGE_SIZE, addr != end);
1787 arch_leave_lazy_mmu_mode();
1788 pte_unmap_unlock(pte - 1, ptl);
1792 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1793 unsigned long addr, unsigned long end,
1794 unsigned long pfn, pgprot_t prot)
1799 pfn -= addr >> PAGE_SHIFT;
1800 pmd = pmd_alloc(mm, pud, addr);
1804 next = pmd_addr_end(addr, end);
1805 if (remap_pte_range(mm, pmd, addr, next,
1806 pfn + (addr >> PAGE_SHIFT), prot))
1808 } while (pmd++, addr = next, addr != end);
1812 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1813 unsigned long addr, unsigned long end,
1814 unsigned long pfn, pgprot_t prot)
1819 pfn -= addr >> PAGE_SHIFT;
1820 pud = pud_alloc(mm, pgd, addr);
1824 next = pud_addr_end(addr, end);
1825 if (remap_pmd_range(mm, pud, addr, next,
1826 pfn + (addr >> PAGE_SHIFT), prot))
1828 } while (pud++, addr = next, addr != end);
1833 * remap_pfn_range - remap kernel memory to userspace
1834 * @vma: user vma to map to
1835 * @addr: target user address to start at
1836 * @pfn: physical address of kernel memory
1837 * @size: size of map area
1838 * @prot: page protection flags for this mapping
1840 * Note: this is only safe if the mm semaphore is held when called.
1842 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1843 unsigned long pfn, unsigned long size, pgprot_t prot)
1847 unsigned long end = addr + PAGE_ALIGN(size);
1848 struct mm_struct *mm = vma->vm_mm;
1852 * Physically remapped pages are special. Tell the
1853 * rest of the world about it:
1854 * VM_IO tells people not to look at these pages
1855 * (accesses can have side effects).
1856 * VM_RESERVED is specified all over the place, because
1857 * in 2.4 it kept swapout's vma scan off this vma; but
1858 * in 2.6 the LRU scan won't even find its pages, so this
1859 * flag means no more than count its pages in reserved_vm,
1860 * and omit it from core dump, even when VM_IO turned off.
1861 * VM_PFNMAP tells the core MM that the base pages are just
1862 * raw PFN mappings, and do not have a "struct page" associated
1865 * There's a horrible special case to handle copy-on-write
1866 * behaviour that some programs depend on. We mark the "original"
1867 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1869 if (addr == vma->vm_start && end == vma->vm_end) {
1870 vma->vm_pgoff = pfn;
1871 vma->vm_flags |= VM_PFN_AT_MMAP;
1872 } else if (is_cow_mapping(vma->vm_flags))
1875 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
1877 err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
1880 * To indicate that track_pfn related cleanup is not
1881 * needed from higher level routine calling unmap_vmas
1883 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
1884 vma->vm_flags &= ~VM_PFN_AT_MMAP;
1888 BUG_ON(addr >= end);
1889 pfn -= addr >> PAGE_SHIFT;
1890 pgd = pgd_offset(mm, addr);
1891 flush_cache_range(vma, addr, end);
1893 next = pgd_addr_end(addr, end);
1894 err = remap_pud_range(mm, pgd, addr, next,
1895 pfn + (addr >> PAGE_SHIFT), prot);
1898 } while (pgd++, addr = next, addr != end);
1901 untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
1905 EXPORT_SYMBOL(remap_pfn_range);
1907 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1908 unsigned long addr, unsigned long end,
1909 pte_fn_t fn, void *data)
1914 spinlock_t *uninitialized_var(ptl);
1916 pte = (mm == &init_mm) ?
1917 pte_alloc_kernel(pmd, addr) :
1918 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1922 BUG_ON(pmd_huge(*pmd));
1924 arch_enter_lazy_mmu_mode();
1926 token = pmd_pgtable(*pmd);
1929 err = fn(pte++, token, addr, data);
1932 } while (addr += PAGE_SIZE, addr != end);
1934 arch_leave_lazy_mmu_mode();
1937 pte_unmap_unlock(pte-1, ptl);
1941 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1942 unsigned long addr, unsigned long end,
1943 pte_fn_t fn, void *data)
1949 BUG_ON(pud_huge(*pud));
1951 pmd = pmd_alloc(mm, pud, addr);
1955 next = pmd_addr_end(addr, end);
1956 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1959 } while (pmd++, addr = next, addr != end);
1963 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1964 unsigned long addr, unsigned long end,
1965 pte_fn_t fn, void *data)
1971 pud = pud_alloc(mm, pgd, addr);
1975 next = pud_addr_end(addr, end);
1976 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1979 } while (pud++, addr = next, addr != end);
1984 * Scan a region of virtual memory, filling in page tables as necessary
1985 * and calling a provided function on each leaf page table.
1987 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1988 unsigned long size, pte_fn_t fn, void *data)
1992 unsigned long start = addr, end = addr + size;
1995 BUG_ON(addr >= end);
1996 mmu_notifier_invalidate_range_start(mm, start, end);
1997 pgd = pgd_offset(mm, addr);
1999 next = pgd_addr_end(addr, end);
2000 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2003 } while (pgd++, addr = next, addr != end);
2004 mmu_notifier_invalidate_range_end(mm, start, end);
2007 EXPORT_SYMBOL_GPL(apply_to_page_range);
2010 * handle_pte_fault chooses page fault handler according to an entry
2011 * which was read non-atomically. Before making any commitment, on
2012 * those architectures or configurations (e.g. i386 with PAE) which
2013 * might give a mix of unmatched parts, do_swap_page and do_file_page
2014 * must check under lock before unmapping the pte and proceeding
2015 * (but do_wp_page is only called after already making such a check;
2016 * and do_anonymous_page and do_no_page can safely check later on).
2018 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2019 pte_t *page_table, pte_t orig_pte)
2022 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2023 if (sizeof(pte_t) > sizeof(unsigned long)) {
2024 spinlock_t *ptl = pte_lockptr(mm, pmd);
2026 same = pte_same(*page_table, orig_pte);
2030 pte_unmap(page_table);
2035 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
2036 * servicing faults for write access. In the normal case, do always want
2037 * pte_mkwrite. But get_user_pages can cause write faults for mappings
2038 * that do not have writing enabled, when used by access_process_vm.
2040 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
2042 if (likely(vma->vm_flags & VM_WRITE))
2043 pte = pte_mkwrite(pte);
2047 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2050 * If the source page was a PFN mapping, we don't have
2051 * a "struct page" for it. We do a best-effort copy by
2052 * just copying from the original user address. If that
2053 * fails, we just zero-fill it. Live with it.
2055 if (unlikely(!src)) {
2056 void *kaddr = kmap_atomic(dst, KM_USER0);
2057 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2060 * This really shouldn't fail, because the page is there
2061 * in the page tables. But it might just be unreadable,
2062 * in which case we just give up and fill the result with
2065 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2066 memset(kaddr, 0, PAGE_SIZE);
2067 kunmap_atomic(kaddr, KM_USER0);
2068 flush_dcache_page(dst);
2070 copy_user_highpage(dst, src, va, vma);
2074 * This routine handles present pages, when users try to write
2075 * to a shared page. It is done by copying the page to a new address
2076 * and decrementing the shared-page counter for the old page.
2078 * Note that this routine assumes that the protection checks have been
2079 * done by the caller (the low-level page fault routine in most cases).
2080 * Thus we can safely just mark it writable once we've done any necessary
2083 * We also mark the page dirty at this point even though the page will
2084 * change only once the write actually happens. This avoids a few races,
2085 * and potentially makes it more efficient.
2087 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2088 * but allow concurrent faults), with pte both mapped and locked.
2089 * We return with mmap_sem still held, but pte unmapped and unlocked.
2091 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2092 unsigned long address, pte_t *page_table, pmd_t *pmd,
2093 spinlock_t *ptl, pte_t orig_pte)
2095 struct page *old_page, *new_page;
2097 int reuse = 0, ret = 0;
2098 int page_mkwrite = 0;
2099 struct page *dirty_page = NULL;
2101 old_page = vm_normal_page(vma, address, orig_pte);
2104 * VM_MIXEDMAP !pfn_valid() case
2106 * We should not cow pages in a shared writeable mapping.
2107 * Just mark the pages writable as we can't do any dirty
2108 * accounting on raw pfn maps.
2110 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2111 (VM_WRITE|VM_SHARED))
2117 * Take out anonymous pages first, anonymous shared vmas are
2118 * not dirty accountable.
2120 if (PageAnon(old_page) && !PageKsm(old_page)) {
2121 if (!trylock_page(old_page)) {
2122 page_cache_get(old_page);
2123 pte_unmap_unlock(page_table, ptl);
2124 lock_page(old_page);
2125 page_table = pte_offset_map_lock(mm, pmd, address,
2127 if (!pte_same(*page_table, orig_pte)) {
2128 unlock_page(old_page);
2129 page_cache_release(old_page);
2132 page_cache_release(old_page);
2134 reuse = reuse_swap_page(old_page);
2137 * The page is all ours. Move it to our anon_vma so
2138 * the rmap code will not search our parent or siblings.
2139 * Protected against the rmap code by the page lock.
2141 page_move_anon_rmap(old_page, vma, address);
2142 unlock_page(old_page);
2143 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2144 (VM_WRITE|VM_SHARED))) {
2146 * Only catch write-faults on shared writable pages,
2147 * read-only shared pages can get COWed by
2148 * get_user_pages(.write=1, .force=1).
2150 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2151 struct vm_fault vmf;
2154 vmf.virtual_address = (void __user *)(address &
2156 vmf.pgoff = old_page->index;
2157 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2158 vmf.page = old_page;
2161 * Notify the address space that the page is about to
2162 * become writable so that it can prohibit this or wait
2163 * for the page to get into an appropriate state.
2165 * We do this without the lock held, so that it can
2166 * sleep if it needs to.
2168 page_cache_get(old_page);
2169 pte_unmap_unlock(page_table, ptl);
2171 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2173 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2175 goto unwritable_page;
2177 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2178 lock_page(old_page);
2179 if (!old_page->mapping) {
2180 ret = 0; /* retry the fault */
2181 unlock_page(old_page);
2182 goto unwritable_page;
2185 VM_BUG_ON(!PageLocked(old_page));
2188 * Since we dropped the lock we need to revalidate
2189 * the PTE as someone else may have changed it. If
2190 * they did, we just return, as we can count on the
2191 * MMU to tell us if they didn't also make it writable.
2193 page_table = pte_offset_map_lock(mm, pmd, address,
2195 if (!pte_same(*page_table, orig_pte)) {
2196 unlock_page(old_page);
2197 page_cache_release(old_page);
2203 dirty_page = old_page;
2204 get_page(dirty_page);
2210 flush_cache_page(vma, address, pte_pfn(orig_pte));
2211 entry = pte_mkyoung(orig_pte);
2212 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2213 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2214 update_mmu_cache(vma, address, page_table);
2215 ret |= VM_FAULT_WRITE;
2220 * Ok, we need to copy. Oh, well..
2222 page_cache_get(old_page);
2224 pte_unmap_unlock(page_table, ptl);
2226 if (unlikely(anon_vma_prepare(vma)))
2229 if (is_zero_pfn(pte_pfn(orig_pte))) {
2230 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2234 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2237 cow_user_page(new_page, old_page, address, vma);
2239 __SetPageUptodate(new_page);
2242 * Don't let another task, with possibly unlocked vma,
2243 * keep the mlocked page.
2245 if ((vma->vm_flags & VM_LOCKED) && old_page) {
2246 lock_page(old_page); /* for LRU manipulation */
2247 clear_page_mlock(old_page);
2248 unlock_page(old_page);
2251 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2255 * Re-check the pte - we dropped the lock
2257 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2258 if (likely(pte_same(*page_table, orig_pte))) {
2260 if (!PageAnon(old_page)) {
2261 dec_mm_counter_fast(mm, MM_FILEPAGES);
2262 inc_mm_counter_fast(mm, MM_ANONPAGES);
2265 inc_mm_counter_fast(mm, MM_ANONPAGES);
2266 flush_cache_page(vma, address, pte_pfn(orig_pte));
2267 entry = mk_pte(new_page, vma->vm_page_prot);
2268 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2270 * Clear the pte entry and flush it first, before updating the
2271 * pte with the new entry. This will avoid a race condition
2272 * seen in the presence of one thread doing SMC and another
2275 ptep_clear_flush(vma, address, page_table);
2276 page_add_new_anon_rmap(new_page, vma, address);
2278 * We call the notify macro here because, when using secondary
2279 * mmu page tables (such as kvm shadow page tables), we want the
2280 * new page to be mapped directly into the secondary page table.
2282 set_pte_at_notify(mm, address, page_table, entry);
2283 update_mmu_cache(vma, address, page_table);
2286 * Only after switching the pte to the new page may
2287 * we remove the mapcount here. Otherwise another
2288 * process may come and find the rmap count decremented
2289 * before the pte is switched to the new page, and
2290 * "reuse" the old page writing into it while our pte
2291 * here still points into it and can be read by other
2294 * The critical issue is to order this
2295 * page_remove_rmap with the ptp_clear_flush above.
2296 * Those stores are ordered by (if nothing else,)
2297 * the barrier present in the atomic_add_negative
2298 * in page_remove_rmap.
2300 * Then the TLB flush in ptep_clear_flush ensures that
2301 * no process can access the old page before the
2302 * decremented mapcount is visible. And the old page
2303 * cannot be reused until after the decremented
2304 * mapcount is visible. So transitively, TLBs to
2305 * old page will be flushed before it can be reused.
2307 page_remove_rmap(old_page);
2310 /* Free the old page.. */
2311 new_page = old_page;
2312 ret |= VM_FAULT_WRITE;
2314 mem_cgroup_uncharge_page(new_page);
2317 page_cache_release(new_page);
2319 page_cache_release(old_page);
2321 pte_unmap_unlock(page_table, ptl);
2324 * Yes, Virginia, this is actually required to prevent a race
2325 * with clear_page_dirty_for_io() from clearing the page dirty
2326 * bit after it clear all dirty ptes, but before a racing
2327 * do_wp_page installs a dirty pte.
2329 * do_no_page is protected similarly.
2331 if (!page_mkwrite) {
2332 wait_on_page_locked(dirty_page);
2333 set_page_dirty_balance(dirty_page, page_mkwrite);
2335 put_page(dirty_page);
2337 struct address_space *mapping = dirty_page->mapping;
2339 set_page_dirty(dirty_page);
2340 unlock_page(dirty_page);
2341 page_cache_release(dirty_page);
2344 * Some device drivers do not set page.mapping
2345 * but still dirty their pages
2347 balance_dirty_pages_ratelimited(mapping);
2351 /* file_update_time outside page_lock */
2353 file_update_time(vma->vm_file);
2357 page_cache_release(new_page);
2361 unlock_page(old_page);
2362 page_cache_release(old_page);
2364 page_cache_release(old_page);
2366 return VM_FAULT_OOM;
2369 page_cache_release(old_page);
2374 * Helper functions for unmap_mapping_range().
2376 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2378 * We have to restart searching the prio_tree whenever we drop the lock,
2379 * since the iterator is only valid while the lock is held, and anyway
2380 * a later vma might be split and reinserted earlier while lock dropped.
2382 * The list of nonlinear vmas could be handled more efficiently, using
2383 * a placeholder, but handle it in the same way until a need is shown.
2384 * It is important to search the prio_tree before nonlinear list: a vma
2385 * may become nonlinear and be shifted from prio_tree to nonlinear list
2386 * while the lock is dropped; but never shifted from list to prio_tree.
2388 * In order to make forward progress despite restarting the search,
2389 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2390 * quickly skip it next time around. Since the prio_tree search only
2391 * shows us those vmas affected by unmapping the range in question, we
2392 * can't efficiently keep all vmas in step with mapping->truncate_count:
2393 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2394 * mapping->truncate_count and vma->vm_truncate_count are protected by
2397 * In order to make forward progress despite repeatedly restarting some
2398 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2399 * and restart from that address when we reach that vma again. It might
2400 * have been split or merged, shrunk or extended, but never shifted: so
2401 * restart_addr remains valid so long as it remains in the vma's range.
2402 * unmap_mapping_range forces truncate_count to leap over page-aligned
2403 * values so we can save vma's restart_addr in its truncate_count field.
2405 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2407 static void reset_vma_truncate_counts(struct address_space *mapping)
2409 struct vm_area_struct *vma;
2410 struct prio_tree_iter iter;
2412 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2413 vma->vm_truncate_count = 0;
2414 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2415 vma->vm_truncate_count = 0;
2418 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2419 unsigned long start_addr, unsigned long end_addr,
2420 struct zap_details *details)
2422 unsigned long restart_addr;
2426 * files that support invalidating or truncating portions of the
2427 * file from under mmaped areas must have their ->fault function
2428 * return a locked page (and set VM_FAULT_LOCKED in the return).
2429 * This provides synchronisation against concurrent unmapping here.
2433 restart_addr = vma->vm_truncate_count;
2434 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2435 start_addr = restart_addr;
2436 if (start_addr >= end_addr) {
2437 /* Top of vma has been split off since last time */
2438 vma->vm_truncate_count = details->truncate_count;
2443 restart_addr = zap_page_range(vma, start_addr,
2444 end_addr - start_addr, details);
2445 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
2447 if (restart_addr >= end_addr) {
2448 /* We have now completed this vma: mark it so */
2449 vma->vm_truncate_count = details->truncate_count;
2453 /* Note restart_addr in vma's truncate_count field */
2454 vma->vm_truncate_count = restart_addr;
2459 spin_unlock(details->i_mmap_lock);
2461 spin_lock(details->i_mmap_lock);
2465 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2466 struct zap_details *details)
2468 struct vm_area_struct *vma;
2469 struct prio_tree_iter iter;
2470 pgoff_t vba, vea, zba, zea;
2473 vma_prio_tree_foreach(vma, &iter, root,
2474 details->first_index, details->last_index) {
2475 /* Skip quickly over those we have already dealt with */
2476 if (vma->vm_truncate_count == details->truncate_count)
2479 vba = vma->vm_pgoff;
2480 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2481 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2482 zba = details->first_index;
2485 zea = details->last_index;
2489 if (unmap_mapping_range_vma(vma,
2490 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2491 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2497 static inline void unmap_mapping_range_list(struct list_head *head,
2498 struct zap_details *details)
2500 struct vm_area_struct *vma;
2503 * In nonlinear VMAs there is no correspondence between virtual address
2504 * offset and file offset. So we must perform an exhaustive search
2505 * across *all* the pages in each nonlinear VMA, not just the pages
2506 * whose virtual address lies outside the file truncation point.
2509 list_for_each_entry(vma, head, shared.vm_set.list) {
2510 /* Skip quickly over those we have already dealt with */
2511 if (vma->vm_truncate_count == details->truncate_count)
2513 details->nonlinear_vma = vma;
2514 if (unmap_mapping_range_vma(vma, vma->vm_start,
2515 vma->vm_end, details) < 0)
2521 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2522 * @mapping: the address space containing mmaps to be unmapped.
2523 * @holebegin: byte in first page to unmap, relative to the start of
2524 * the underlying file. This will be rounded down to a PAGE_SIZE
2525 * boundary. Note that this is different from truncate_pagecache(), which
2526 * must keep the partial page. In contrast, we must get rid of
2528 * @holelen: size of prospective hole in bytes. This will be rounded
2529 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2531 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2532 * but 0 when invalidating pagecache, don't throw away private data.
2534 void unmap_mapping_range(struct address_space *mapping,
2535 loff_t const holebegin, loff_t const holelen, int even_cows)
2537 struct zap_details details;
2538 pgoff_t hba = holebegin >> PAGE_SHIFT;
2539 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2541 /* Check for overflow. */
2542 if (sizeof(holelen) > sizeof(hlen)) {
2544 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2545 if (holeend & ~(long long)ULONG_MAX)
2546 hlen = ULONG_MAX - hba + 1;
2549 details.check_mapping = even_cows? NULL: mapping;
2550 details.nonlinear_vma = NULL;
2551 details.first_index = hba;
2552 details.last_index = hba + hlen - 1;
2553 if (details.last_index < details.first_index)
2554 details.last_index = ULONG_MAX;
2555 details.i_mmap_lock = &mapping->i_mmap_lock;
2557 spin_lock(&mapping->i_mmap_lock);
2559 /* Protect against endless unmapping loops */
2560 mapping->truncate_count++;
2561 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2562 if (mapping->truncate_count == 0)
2563 reset_vma_truncate_counts(mapping);
2564 mapping->truncate_count++;
2566 details.truncate_count = mapping->truncate_count;
2568 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2569 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2570 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2571 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2572 spin_unlock(&mapping->i_mmap_lock);
2574 EXPORT_SYMBOL(unmap_mapping_range);
2576 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2578 struct address_space *mapping = inode->i_mapping;
2581 * If the underlying filesystem is not going to provide
2582 * a way to truncate a range of blocks (punch a hole) -
2583 * we should return failure right now.
2585 if (!inode->i_op->truncate_range)
2588 mutex_lock(&inode->i_mutex);
2589 down_write(&inode->i_alloc_sem);
2590 unmap_mapping_range(mapping, offset, (end - offset), 1);
2591 truncate_inode_pages_range(mapping, offset, end);
2592 unmap_mapping_range(mapping, offset, (end - offset), 1);
2593 inode->i_op->truncate_range(inode, offset, end);
2594 up_write(&inode->i_alloc_sem);
2595 mutex_unlock(&inode->i_mutex);
2601 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2602 * but allow concurrent faults), and pte mapped but not yet locked.
2603 * We return with mmap_sem still held, but pte unmapped and unlocked.
2605 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2606 unsigned long address, pte_t *page_table, pmd_t *pmd,
2607 unsigned int flags, pte_t orig_pte)
2613 struct mem_cgroup *ptr = NULL;
2616 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2619 entry = pte_to_swp_entry(orig_pte);
2620 if (unlikely(non_swap_entry(entry))) {
2621 if (is_migration_entry(entry)) {
2622 migration_entry_wait(mm, pmd, address);
2623 } else if (is_hwpoison_entry(entry)) {
2624 ret = VM_FAULT_HWPOISON;
2626 print_bad_pte(vma, address, orig_pte, NULL);
2627 ret = VM_FAULT_SIGBUS;
2631 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2632 page = lookup_swap_cache(entry);
2634 grab_swap_token(mm); /* Contend for token _before_ read-in */
2635 page = swapin_readahead(entry,
2636 GFP_HIGHUSER_MOVABLE, vma, address);
2639 * Back out if somebody else faulted in this pte
2640 * while we released the pte lock.
2642 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2643 if (likely(pte_same(*page_table, orig_pte)))
2645 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2649 /* Had to read the page from swap area: Major fault */
2650 ret = VM_FAULT_MAJOR;
2651 count_vm_event(PGMAJFAULT);
2652 } else if (PageHWPoison(page)) {
2654 * hwpoisoned dirty swapcache pages are kept for killing
2655 * owner processes (which may be unknown at hwpoison time)
2657 ret = VM_FAULT_HWPOISON;
2658 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2663 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2665 page = ksm_might_need_to_copy(page, vma, address);
2671 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
2677 * Back out if somebody else already faulted in this pte.
2679 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2680 if (unlikely(!pte_same(*page_table, orig_pte)))
2683 if (unlikely(!PageUptodate(page))) {
2684 ret = VM_FAULT_SIGBUS;
2689 * The page isn't present yet, go ahead with the fault.
2691 * Be careful about the sequence of operations here.
2692 * To get its accounting right, reuse_swap_page() must be called
2693 * while the page is counted on swap but not yet in mapcount i.e.
2694 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2695 * must be called after the swap_free(), or it will never succeed.
2696 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2697 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2698 * in page->private. In this case, a record in swap_cgroup is silently
2699 * discarded at swap_free().
2702 inc_mm_counter_fast(mm, MM_ANONPAGES);
2703 dec_mm_counter_fast(mm, MM_SWAPENTS);
2704 pte = mk_pte(page, vma->vm_page_prot);
2705 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
2706 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2707 flags &= ~FAULT_FLAG_WRITE;
2709 flush_icache_page(vma, page);
2710 set_pte_at(mm, address, page_table, pte);
2711 page_add_anon_rmap(page, vma, address);
2712 /* It's better to call commit-charge after rmap is established */
2713 mem_cgroup_commit_charge_swapin(page, ptr);
2716 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
2717 try_to_free_swap(page);
2720 if (flags & FAULT_FLAG_WRITE) {
2721 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2722 if (ret & VM_FAULT_ERROR)
2723 ret &= VM_FAULT_ERROR;
2727 /* No need to invalidate - it was non-present before */
2728 update_mmu_cache(vma, address, page_table);
2730 pte_unmap_unlock(page_table, ptl);
2734 mem_cgroup_cancel_charge_swapin(ptr);
2735 pte_unmap_unlock(page_table, ptl);
2739 page_cache_release(page);
2744 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2745 * but allow concurrent faults), and pte mapped but not yet locked.
2746 * We return with mmap_sem still held, but pte unmapped and unlocked.
2748 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2749 unsigned long address, pte_t *page_table, pmd_t *pmd,
2756 if (!(flags & FAULT_FLAG_WRITE)) {
2757 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2758 vma->vm_page_prot));
2759 ptl = pte_lockptr(mm, pmd);
2761 if (!pte_none(*page_table))
2766 /* Allocate our own private page. */
2767 pte_unmap(page_table);
2769 if (unlikely(anon_vma_prepare(vma)))
2771 page = alloc_zeroed_user_highpage_movable(vma, address);
2774 __SetPageUptodate(page);
2776 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
2779 entry = mk_pte(page, vma->vm_page_prot);
2780 if (vma->vm_flags & VM_WRITE)
2781 entry = pte_mkwrite(pte_mkdirty(entry));
2783 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2784 if (!pte_none(*page_table))
2787 inc_mm_counter_fast(mm, MM_ANONPAGES);
2788 page_add_new_anon_rmap(page, vma, address);
2790 set_pte_at(mm, address, page_table, entry);
2792 /* No need to invalidate - it was non-present before */
2793 update_mmu_cache(vma, address, page_table);
2795 pte_unmap_unlock(page_table, ptl);
2798 mem_cgroup_uncharge_page(page);
2799 page_cache_release(page);
2802 page_cache_release(page);
2804 return VM_FAULT_OOM;
2808 * __do_fault() tries to create a new page mapping. It aggressively
2809 * tries to share with existing pages, but makes a separate copy if
2810 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2811 * the next page fault.
2813 * As this is called only for pages that do not currently exist, we
2814 * do not need to flush old virtual caches or the TLB.
2816 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2817 * but allow concurrent faults), and pte neither mapped nor locked.
2818 * We return with mmap_sem still held, but pte unmapped and unlocked.
2820 static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2821 unsigned long address, pmd_t *pmd,
2822 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
2830 struct page *dirty_page = NULL;
2831 struct vm_fault vmf;
2833 int page_mkwrite = 0;
2835 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2840 ret = vma->vm_ops->fault(vma, &vmf);
2841 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2844 if (unlikely(PageHWPoison(vmf.page))) {
2845 if (ret & VM_FAULT_LOCKED)
2846 unlock_page(vmf.page);
2847 return VM_FAULT_HWPOISON;
2851 * For consistency in subsequent calls, make the faulted page always
2854 if (unlikely(!(ret & VM_FAULT_LOCKED)))
2855 lock_page(vmf.page);
2857 VM_BUG_ON(!PageLocked(vmf.page));
2860 * Should we do an early C-O-W break?
2863 if (flags & FAULT_FLAG_WRITE) {
2864 if (!(vma->vm_flags & VM_SHARED)) {
2866 if (unlikely(anon_vma_prepare(vma))) {
2870 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2876 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
2878 page_cache_release(page);
2883 * Don't let another task, with possibly unlocked vma,
2884 * keep the mlocked page.
2886 if (vma->vm_flags & VM_LOCKED)
2887 clear_page_mlock(vmf.page);
2888 copy_user_highpage(page, vmf.page, address, vma);
2889 __SetPageUptodate(page);
2892 * If the page will be shareable, see if the backing
2893 * address space wants to know that the page is about
2894 * to become writable
2896 if (vma->vm_ops->page_mkwrite) {
2900 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2901 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2903 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2905 goto unwritable_page;
2907 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2909 if (!page->mapping) {
2910 ret = 0; /* retry the fault */
2912 goto unwritable_page;
2915 VM_BUG_ON(!PageLocked(page));
2922 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2925 * This silly early PAGE_DIRTY setting removes a race
2926 * due to the bad i386 page protection. But it's valid
2927 * for other architectures too.
2929 * Note that if FAULT_FLAG_WRITE is set, we either now have
2930 * an exclusive copy of the page, or this is a shared mapping,
2931 * so we can make it writable and dirty to avoid having to
2932 * handle that later.
2934 /* Only go through if we didn't race with anybody else... */
2935 if (likely(pte_same(*page_table, orig_pte))) {
2936 flush_icache_page(vma, page);
2937 entry = mk_pte(page, vma->vm_page_prot);
2938 if (flags & FAULT_FLAG_WRITE)
2939 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2941 inc_mm_counter_fast(mm, MM_ANONPAGES);
2942 page_add_new_anon_rmap(page, vma, address);
2944 inc_mm_counter_fast(mm, MM_FILEPAGES);
2945 page_add_file_rmap(page);
2946 if (flags & FAULT_FLAG_WRITE) {
2948 get_page(dirty_page);
2951 set_pte_at(mm, address, page_table, entry);
2953 /* no need to invalidate: a not-present page won't be cached */
2954 update_mmu_cache(vma, address, page_table);
2957 mem_cgroup_uncharge_page(page);
2959 page_cache_release(page);
2961 anon = 1; /* no anon but release faulted_page */
2964 pte_unmap_unlock(page_table, ptl);
2968 struct address_space *mapping = page->mapping;
2970 if (set_page_dirty(dirty_page))
2972 unlock_page(dirty_page);
2973 put_page(dirty_page);
2974 if (page_mkwrite && mapping) {
2976 * Some device drivers do not set page.mapping but still
2979 balance_dirty_pages_ratelimited(mapping);
2982 /* file_update_time outside page_lock */
2984 file_update_time(vma->vm_file);
2986 unlock_page(vmf.page);
2988 page_cache_release(vmf.page);
2994 page_cache_release(page);
2998 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2999 unsigned long address, pte_t *page_table, pmd_t *pmd,
3000 unsigned int flags, pte_t orig_pte)
3002 pgoff_t pgoff = (((address & PAGE_MASK)
3003 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3005 pte_unmap(page_table);
3006 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3010 * Fault of a previously existing named mapping. Repopulate the pte
3011 * from the encoded file_pte if possible. This enables swappable
3014 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3015 * but allow concurrent faults), and pte mapped but not yet locked.
3016 * We return with mmap_sem still held, but pte unmapped and unlocked.
3018 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3019 unsigned long address, pte_t *page_table, pmd_t *pmd,
3020 unsigned int flags, pte_t orig_pte)
3024 flags |= FAULT_FLAG_NONLINEAR;
3026 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3029 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3031 * Page table corrupted: show pte and kill process.
3033 print_bad_pte(vma, address, orig_pte, NULL);
3034 return VM_FAULT_SIGBUS;
3037 pgoff = pte_to_pgoff(orig_pte);
3038 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3042 * These routines also need to handle stuff like marking pages dirty
3043 * and/or accessed for architectures that don't do it in hardware (most
3044 * RISC architectures). The early dirtying is also good on the i386.
3046 * There is also a hook called "update_mmu_cache()" that architectures
3047 * with external mmu caches can use to update those (ie the Sparc or
3048 * PowerPC hashed page tables that act as extended TLBs).
3050 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3051 * but allow concurrent faults), and pte mapped but not yet locked.
3052 * We return with mmap_sem still held, but pte unmapped and unlocked.
3054 static inline int handle_pte_fault(struct mm_struct *mm,
3055 struct vm_area_struct *vma, unsigned long address,
3056 pte_t *pte, pmd_t *pmd, unsigned int flags)
3062 if (!pte_present(entry)) {
3063 if (pte_none(entry)) {
3065 if (likely(vma->vm_ops->fault))
3066 return do_linear_fault(mm, vma, address,
3067 pte, pmd, flags, entry);
3069 return do_anonymous_page(mm, vma, address,
3072 if (pte_file(entry))
3073 return do_nonlinear_fault(mm, vma, address,
3074 pte, pmd, flags, entry);
3075 return do_swap_page(mm, vma, address,
3076 pte, pmd, flags, entry);
3079 ptl = pte_lockptr(mm, pmd);
3081 if (unlikely(!pte_same(*pte, entry)))
3083 if (flags & FAULT_FLAG_WRITE) {
3084 if (!pte_write(entry))
3085 return do_wp_page(mm, vma, address,
3086 pte, pmd, ptl, entry);
3087 entry = pte_mkdirty(entry);
3089 entry = pte_mkyoung(entry);
3090 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3091 update_mmu_cache(vma, address, pte);
3094 * This is needed only for protection faults but the arch code
3095 * is not yet telling us if this is a protection fault or not.
3096 * This still avoids useless tlb flushes for .text page faults
3099 if (flags & FAULT_FLAG_WRITE)
3100 flush_tlb_page(vma, address);
3103 pte_unmap_unlock(pte, ptl);
3108 * By the time we get here, we already hold the mm semaphore
3110 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3111 unsigned long address, unsigned int flags)
3118 __set_current_state(TASK_RUNNING);
3120 count_vm_event(PGFAULT);
3122 /* do counter updates before entering really critical section. */
3123 check_sync_rss_stat(current);
3125 if (unlikely(is_vm_hugetlb_page(vma)))
3126 return hugetlb_fault(mm, vma, address, flags);
3128 pgd = pgd_offset(mm, address);
3129 pud = pud_alloc(mm, pgd, address);
3131 return VM_FAULT_OOM;
3132 pmd = pmd_alloc(mm, pud, address);
3134 return VM_FAULT_OOM;
3135 pte = pte_alloc_map(mm, pmd, address);
3137 return VM_FAULT_OOM;
3139 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3142 #ifndef __PAGETABLE_PUD_FOLDED
3144 * Allocate page upper directory.
3145 * We've already handled the fast-path in-line.
3147 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3149 pud_t *new = pud_alloc_one(mm, address);
3153 smp_wmb(); /* See comment in __pte_alloc */
3155 spin_lock(&mm->page_table_lock);
3156 if (pgd_present(*pgd)) /* Another has populated it */
3159 pgd_populate(mm, pgd, new);
3160 spin_unlock(&mm->page_table_lock);
3163 #endif /* __PAGETABLE_PUD_FOLDED */
3165 #ifndef __PAGETABLE_PMD_FOLDED
3167 * Allocate page middle directory.
3168 * We've already handled the fast-path in-line.
3170 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3172 pmd_t *new = pmd_alloc_one(mm, address);
3176 smp_wmb(); /* See comment in __pte_alloc */
3178 spin_lock(&mm->page_table_lock);
3179 #ifndef __ARCH_HAS_4LEVEL_HACK
3180 if (pud_present(*pud)) /* Another has populated it */
3183 pud_populate(mm, pud, new);
3185 if (pgd_present(*pud)) /* Another has populated it */
3188 pgd_populate(mm, pud, new);
3189 #endif /* __ARCH_HAS_4LEVEL_HACK */
3190 spin_unlock(&mm->page_table_lock);
3193 #endif /* __PAGETABLE_PMD_FOLDED */
3195 int make_pages_present(unsigned long addr, unsigned long end)
3197 int ret, len, write;
3198 struct vm_area_struct * vma;
3200 vma = find_vma(current->mm, addr);
3203 write = (vma->vm_flags & VM_WRITE) != 0;
3204 BUG_ON(addr >= end);
3205 BUG_ON(end > vma->vm_end);
3206 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
3207 ret = get_user_pages(current, current->mm, addr,
3208 len, write, 0, NULL, NULL);
3211 return ret == len ? 0 : -EFAULT;
3214 #if !defined(__HAVE_ARCH_GATE_AREA)
3216 #if defined(AT_SYSINFO_EHDR)
3217 static struct vm_area_struct gate_vma;
3219 static int __init gate_vma_init(void)
3221 gate_vma.vm_mm = NULL;
3222 gate_vma.vm_start = FIXADDR_USER_START;
3223 gate_vma.vm_end = FIXADDR_USER_END;
3224 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3225 gate_vma.vm_page_prot = __P101;
3227 * Make sure the vDSO gets into every core dump.
3228 * Dumping its contents makes post-mortem fully interpretable later
3229 * without matching up the same kernel and hardware config to see
3230 * what PC values meant.
3232 gate_vma.vm_flags |= VM_ALWAYSDUMP;
3235 __initcall(gate_vma_init);
3238 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
3240 #ifdef AT_SYSINFO_EHDR
3247 int in_gate_area_no_task(unsigned long addr)
3249 #ifdef AT_SYSINFO_EHDR
3250 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3256 #endif /* __HAVE_ARCH_GATE_AREA */
3258 static int follow_pte(struct mm_struct *mm, unsigned long address,
3259 pte_t **ptepp, spinlock_t **ptlp)
3266 pgd = pgd_offset(mm, address);
3267 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3270 pud = pud_offset(pgd, address);
3271 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3274 pmd = pmd_offset(pud, address);
3275 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3278 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3282 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3285 if (!pte_present(*ptep))
3290 pte_unmap_unlock(ptep, *ptlp);
3296 * follow_pfn - look up PFN at a user virtual address
3297 * @vma: memory mapping
3298 * @address: user virtual address
3299 * @pfn: location to store found PFN
3301 * Only IO mappings and raw PFN mappings are allowed.
3303 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3305 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3312 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3315 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3318 *pfn = pte_pfn(*ptep);
3319 pte_unmap_unlock(ptep, ptl);
3322 EXPORT_SYMBOL(follow_pfn);
3324 #ifdef CONFIG_HAVE_IOREMAP_PROT
3325 int follow_phys(struct vm_area_struct *vma,
3326 unsigned long address, unsigned int flags,
3327 unsigned long *prot, resource_size_t *phys)
3333 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3336 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
3340 if ((flags & FOLL_WRITE) && !pte_write(pte))
3343 *prot = pgprot_val(pte_pgprot(pte));
3344 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
3348 pte_unmap_unlock(ptep, ptl);
3353 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3354 void *buf, int len, int write)
3356 resource_size_t phys_addr;
3357 unsigned long prot = 0;
3358 void __iomem *maddr;
3359 int offset = addr & (PAGE_SIZE-1);
3361 if (follow_phys(vma, addr, write, &prot, &phys_addr))
3364 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3366 memcpy_toio(maddr + offset, buf, len);
3368 memcpy_fromio(buf, maddr + offset, len);
3376 * Access another process' address space.
3377 * Source/target buffer must be kernel space,
3378 * Do not walk the page table directly, use get_user_pages
3380 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
3382 struct mm_struct *mm;
3383 struct vm_area_struct *vma;
3384 void *old_buf = buf;
3386 mm = get_task_mm(tsk);
3390 down_read(&mm->mmap_sem);
3391 /* ignore errors, just check how much was successfully transferred */
3393 int bytes, ret, offset;
3395 struct page *page = NULL;
3397 ret = get_user_pages(tsk, mm, addr, 1,
3398 write, 1, &page, &vma);
3401 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3402 * we can access using slightly different code.
3404 #ifdef CONFIG_HAVE_IOREMAP_PROT
3405 vma = find_vma(mm, addr);
3408 if (vma->vm_ops && vma->vm_ops->access)
3409 ret = vma->vm_ops->access(vma, addr, buf,
3417 offset = addr & (PAGE_SIZE-1);
3418 if (bytes > PAGE_SIZE-offset)
3419 bytes = PAGE_SIZE-offset;
3423 copy_to_user_page(vma, page, addr,
3424 maddr + offset, buf, bytes);
3425 set_page_dirty_lock(page);
3427 copy_from_user_page(vma, page, addr,
3428 buf, maddr + offset, bytes);
3431 page_cache_release(page);
3437 up_read(&mm->mmap_sem);
3440 return buf - old_buf;
3444 * Print the name of a VMA.
3446 void print_vma_addr(char *prefix, unsigned long ip)
3448 struct mm_struct *mm = current->mm;
3449 struct vm_area_struct *vma;
3452 * Do not print if we are in atomic
3453 * contexts (in exception stacks, etc.):
3455 if (preempt_count())
3458 down_read(&mm->mmap_sem);
3459 vma = find_vma(mm, ip);
3460 if (vma && vma->vm_file) {
3461 struct file *f = vma->vm_file;
3462 char *buf = (char *)__get_free_page(GFP_KERNEL);
3466 p = d_path(&f->f_path, buf, PAGE_SIZE);
3469 s = strrchr(p, '/');
3472 printk("%s%s[%lx+%lx]", prefix, p,
3474 vma->vm_end - vma->vm_start);
3475 free_page((unsigned long)buf);
3478 up_read(¤t->mm->mmap_sem);
3481 #ifdef CONFIG_PROVE_LOCKING
3482 void might_fault(void)
3485 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3486 * holding the mmap_sem, this is safe because kernel memory doesn't
3487 * get paged out, therefore we'll never actually fault, and the
3488 * below annotations will generate false positives.
3490 if (segment_eq(get_fs(), KERNEL_DS))
3495 * it would be nicer only to annotate paths which are not under
3496 * pagefault_disable, however that requires a larger audit and
3497 * providing helpers like get_user_atomic.
3499 if (!in_atomic() && current->mm)
3500 might_lock_read(¤t->mm->mmap_sem);
3502 EXPORT_SYMBOL(might_fault);