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/export.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>
60 #include <linux/migrate.h>
61 #include <linux/string.h>
64 #include <asm/pgalloc.h>
65 #include <asm/uaccess.h>
67 #include <asm/tlbflush.h>
68 #include <asm/pgtable.h>
72 #ifdef LAST_NID_NOT_IN_PAGE_FLAGS
73 #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_nid.
76 #ifndef CONFIG_NEED_MULTIPLE_NODES
77 /* use the per-pgdat data instead for discontigmem - mbligh */
78 unsigned long max_mapnr;
81 EXPORT_SYMBOL(max_mapnr);
82 EXPORT_SYMBOL(mem_map);
85 unsigned long num_physpages;
87 * A number of key systems in x86 including ioremap() rely on the assumption
88 * that high_memory defines the upper bound on direct map memory, then end
89 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
90 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
95 EXPORT_SYMBOL(num_physpages);
96 EXPORT_SYMBOL(high_memory);
99 * Randomize the address space (stacks, mmaps, brk, etc.).
101 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
102 * as ancient (libc5 based) binaries can segfault. )
104 int randomize_va_space __read_mostly =
105 #ifdef CONFIG_COMPAT_BRK
111 static int __init disable_randmaps(char *s)
113 randomize_va_space = 0;
116 __setup("norandmaps", disable_randmaps);
118 unsigned long zero_pfn __read_mostly;
119 unsigned long highest_memmap_pfn __read_mostly;
122 * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
124 static int __init init_zero_pfn(void)
126 zero_pfn = page_to_pfn(ZERO_PAGE(0));
129 core_initcall(init_zero_pfn);
132 #if defined(SPLIT_RSS_COUNTING)
134 void sync_mm_rss(struct mm_struct *mm)
138 for (i = 0; i < NR_MM_COUNTERS; i++) {
139 if (current->rss_stat.count[i]) {
140 add_mm_counter(mm, i, current->rss_stat.count[i]);
141 current->rss_stat.count[i] = 0;
144 current->rss_stat.events = 0;
147 static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
149 struct task_struct *task = current;
151 if (likely(task->mm == mm))
152 task->rss_stat.count[member] += val;
154 add_mm_counter(mm, member, val);
156 #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
157 #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
159 /* sync counter once per 64 page faults */
160 #define TASK_RSS_EVENTS_THRESH (64)
161 static void check_sync_rss_stat(struct task_struct *task)
163 if (unlikely(task != current))
165 if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
166 sync_mm_rss(task->mm);
168 #else /* SPLIT_RSS_COUNTING */
170 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
171 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
173 static void check_sync_rss_stat(struct task_struct *task)
177 #endif /* SPLIT_RSS_COUNTING */
179 #ifdef HAVE_GENERIC_MMU_GATHER
181 static int tlb_next_batch(struct mmu_gather *tlb)
183 struct mmu_gather_batch *batch;
187 tlb->active = batch->next;
191 if (tlb->batch_count == MAX_GATHER_BATCH_COUNT)
194 batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
201 batch->max = MAX_GATHER_BATCH;
203 tlb->active->next = batch;
210 * Called to initialize an (on-stack) mmu_gather structure for page-table
211 * tear-down from @mm. The @fullmm argument is used when @mm is without
212 * users and we're going to destroy the full address space (exit/execve).
214 void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm)
218 tlb->fullmm = fullmm;
222 tlb->fast_mode = (num_possible_cpus() == 1);
223 tlb->local.next = NULL;
225 tlb->local.max = ARRAY_SIZE(tlb->__pages);
226 tlb->active = &tlb->local;
227 tlb->batch_count = 0;
229 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
234 void tlb_flush_mmu(struct mmu_gather *tlb)
236 struct mmu_gather_batch *batch;
238 if (!tlb->need_flush)
242 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
243 tlb_table_flush(tlb);
246 if (tlb_fast_mode(tlb))
249 for (batch = &tlb->local; batch; batch = batch->next) {
250 free_pages_and_swap_cache(batch->pages, batch->nr);
253 tlb->active = &tlb->local;
257 * Called at the end of the shootdown operation to free up any resources
258 * that were required.
260 void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
262 struct mmu_gather_batch *batch, *next;
268 /* keep the page table cache within bounds */
271 for (batch = tlb->local.next; batch; batch = next) {
273 free_pages((unsigned long)batch, 0);
275 tlb->local.next = NULL;
279 * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
280 * handling the additional races in SMP caused by other CPUs caching valid
281 * mappings in their TLBs. Returns the number of free page slots left.
282 * When out of page slots we must call tlb_flush_mmu().
284 int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
286 struct mmu_gather_batch *batch;
288 VM_BUG_ON(!tlb->need_flush);
290 if (tlb_fast_mode(tlb)) {
291 free_page_and_swap_cache(page);
292 return 1; /* avoid calling tlb_flush_mmu() */
296 batch->pages[batch->nr++] = page;
297 if (batch->nr == batch->max) {
298 if (!tlb_next_batch(tlb))
302 VM_BUG_ON(batch->nr > batch->max);
304 return batch->max - batch->nr;
307 #endif /* HAVE_GENERIC_MMU_GATHER */
309 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
312 * See the comment near struct mmu_table_batch.
315 static void tlb_remove_table_smp_sync(void *arg)
317 /* Simply deliver the interrupt */
320 static void tlb_remove_table_one(void *table)
323 * This isn't an RCU grace period and hence the page-tables cannot be
324 * assumed to be actually RCU-freed.
326 * It is however sufficient for software page-table walkers that rely on
327 * IRQ disabling. See the comment near struct mmu_table_batch.
329 smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
330 __tlb_remove_table(table);
333 static void tlb_remove_table_rcu(struct rcu_head *head)
335 struct mmu_table_batch *batch;
338 batch = container_of(head, struct mmu_table_batch, rcu);
340 for (i = 0; i < batch->nr; i++)
341 __tlb_remove_table(batch->tables[i]);
343 free_page((unsigned long)batch);
346 void tlb_table_flush(struct mmu_gather *tlb)
348 struct mmu_table_batch **batch = &tlb->batch;
351 call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
356 void tlb_remove_table(struct mmu_gather *tlb, void *table)
358 struct mmu_table_batch **batch = &tlb->batch;
363 * When there's less then two users of this mm there cannot be a
364 * concurrent page-table walk.
366 if (atomic_read(&tlb->mm->mm_users) < 2) {
367 __tlb_remove_table(table);
371 if (*batch == NULL) {
372 *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
373 if (*batch == NULL) {
374 tlb_remove_table_one(table);
379 (*batch)->tables[(*batch)->nr++] = table;
380 if ((*batch)->nr == MAX_TABLE_BATCH)
381 tlb_table_flush(tlb);
384 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
387 * If a p?d_bad entry is found while walking page tables, report
388 * the error, before resetting entry to p?d_none. Usually (but
389 * very seldom) called out from the p?d_none_or_clear_bad macros.
392 void pgd_clear_bad(pgd_t *pgd)
398 void pud_clear_bad(pud_t *pud)
404 void pmd_clear_bad(pmd_t *pmd)
411 * Note: this doesn't free the actual pages themselves. That
412 * has been handled earlier when unmapping all the memory regions.
414 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
417 pgtable_t token = pmd_pgtable(*pmd);
419 pte_free_tlb(tlb, token, addr);
423 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
424 unsigned long addr, unsigned long end,
425 unsigned long floor, unsigned long ceiling)
432 pmd = pmd_offset(pud, addr);
434 next = pmd_addr_end(addr, end);
435 if (pmd_none_or_clear_bad(pmd))
437 free_pte_range(tlb, pmd, addr);
438 } while (pmd++, addr = next, addr != end);
448 if (end - 1 > ceiling - 1)
451 pmd = pmd_offset(pud, start);
453 pmd_free_tlb(tlb, pmd, start);
456 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
457 unsigned long addr, unsigned long end,
458 unsigned long floor, unsigned long ceiling)
465 pud = pud_offset(pgd, addr);
467 next = pud_addr_end(addr, end);
468 if (pud_none_or_clear_bad(pud))
470 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
471 } while (pud++, addr = next, addr != end);
477 ceiling &= PGDIR_MASK;
481 if (end - 1 > ceiling - 1)
484 pud = pud_offset(pgd, start);
486 pud_free_tlb(tlb, pud, start);
490 * This function frees user-level page tables of a process.
492 * Must be called with pagetable lock held.
494 void free_pgd_range(struct mmu_gather *tlb,
495 unsigned long addr, unsigned long end,
496 unsigned long floor, unsigned long ceiling)
502 * The next few lines have given us lots of grief...
504 * Why are we testing PMD* at this top level? Because often
505 * there will be no work to do at all, and we'd prefer not to
506 * go all the way down to the bottom just to discover that.
508 * Why all these "- 1"s? Because 0 represents both the bottom
509 * of the address space and the top of it (using -1 for the
510 * top wouldn't help much: the masks would do the wrong thing).
511 * The rule is that addr 0 and floor 0 refer to the bottom of
512 * the address space, but end 0 and ceiling 0 refer to the top
513 * Comparisons need to use "end - 1" and "ceiling - 1" (though
514 * that end 0 case should be mythical).
516 * Wherever addr is brought up or ceiling brought down, we must
517 * be careful to reject "the opposite 0" before it confuses the
518 * subsequent tests. But what about where end is brought down
519 * by PMD_SIZE below? no, end can't go down to 0 there.
521 * Whereas we round start (addr) and ceiling down, by different
522 * masks at different levels, in order to test whether a table
523 * now has no other vmas using it, so can be freed, we don't
524 * bother to round floor or end up - the tests don't need that.
538 if (end - 1 > ceiling - 1)
543 pgd = pgd_offset(tlb->mm, addr);
545 next = pgd_addr_end(addr, end);
546 if (pgd_none_or_clear_bad(pgd))
548 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
549 } while (pgd++, addr = next, addr != end);
552 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
553 unsigned long floor, unsigned long ceiling)
556 struct vm_area_struct *next = vma->vm_next;
557 unsigned long addr = vma->vm_start;
560 * Hide vma from rmap and truncate_pagecache before freeing
563 unlink_anon_vmas(vma);
564 unlink_file_vma(vma);
566 if (is_vm_hugetlb_page(vma)) {
567 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
568 floor, next? next->vm_start: ceiling);
571 * Optimization: gather nearby vmas into one call down
573 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
574 && !is_vm_hugetlb_page(next)) {
577 unlink_anon_vmas(vma);
578 unlink_file_vma(vma);
580 free_pgd_range(tlb, addr, vma->vm_end,
581 floor, next? next->vm_start: ceiling);
587 int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
588 pmd_t *pmd, unsigned long address)
590 pgtable_t new = pte_alloc_one(mm, address);
591 int wait_split_huge_page;
596 * Ensure all pte setup (eg. pte page lock and page clearing) are
597 * visible before the pte is made visible to other CPUs by being
598 * put into page tables.
600 * The other side of the story is the pointer chasing in the page
601 * table walking code (when walking the page table without locking;
602 * ie. most of the time). Fortunately, these data accesses consist
603 * of a chain of data-dependent loads, meaning most CPUs (alpha
604 * being the notable exception) will already guarantee loads are
605 * seen in-order. See the alpha page table accessors for the
606 * smp_read_barrier_depends() barriers in page table walking code.
608 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
610 spin_lock(&mm->page_table_lock);
611 wait_split_huge_page = 0;
612 if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
614 pmd_populate(mm, pmd, new);
616 } else if (unlikely(pmd_trans_splitting(*pmd)))
617 wait_split_huge_page = 1;
618 spin_unlock(&mm->page_table_lock);
621 if (wait_split_huge_page)
622 wait_split_huge_page(vma->anon_vma, pmd);
626 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
628 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
632 smp_wmb(); /* See comment in __pte_alloc */
634 spin_lock(&init_mm.page_table_lock);
635 if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
636 pmd_populate_kernel(&init_mm, pmd, new);
639 VM_BUG_ON(pmd_trans_splitting(*pmd));
640 spin_unlock(&init_mm.page_table_lock);
642 pte_free_kernel(&init_mm, new);
646 static inline void init_rss_vec(int *rss)
648 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
651 static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
655 if (current->mm == mm)
657 for (i = 0; i < NR_MM_COUNTERS; i++)
659 add_mm_counter(mm, i, rss[i]);
663 * This function is called to print an error when a bad pte
664 * is found. For example, we might have a PFN-mapped pte in
665 * a region that doesn't allow it.
667 * The calling function must still handle the error.
669 static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
670 pte_t pte, struct page *page)
672 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
673 pud_t *pud = pud_offset(pgd, addr);
674 pmd_t *pmd = pmd_offset(pud, addr);
675 struct address_space *mapping;
677 static unsigned long resume;
678 static unsigned long nr_shown;
679 static unsigned long nr_unshown;
682 * Allow a burst of 60 reports, then keep quiet for that minute;
683 * or allow a steady drip of one report per second.
685 if (nr_shown == 60) {
686 if (time_before(jiffies, resume)) {
692 "BUG: Bad page map: %lu messages suppressed\n",
699 resume = jiffies + 60 * HZ;
701 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
702 index = linear_page_index(vma, addr);
705 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
707 (long long)pte_val(pte), (long long)pmd_val(*pmd));
711 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
712 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
714 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
717 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
718 (unsigned long)vma->vm_ops->fault);
719 if (vma->vm_file && vma->vm_file->f_op)
720 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
721 (unsigned long)vma->vm_file->f_op->mmap);
723 add_taint(TAINT_BAD_PAGE);
726 static inline bool is_cow_mapping(vm_flags_t flags)
728 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
732 * vm_normal_page -- This function gets the "struct page" associated with a pte.
734 * "Special" mappings do not wish to be associated with a "struct page" (either
735 * it doesn't exist, or it exists but they don't want to touch it). In this
736 * case, NULL is returned here. "Normal" mappings do have a struct page.
738 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
739 * pte bit, in which case this function is trivial. Secondly, an architecture
740 * may not have a spare pte bit, which requires a more complicated scheme,
743 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
744 * special mapping (even if there are underlying and valid "struct pages").
745 * COWed pages of a VM_PFNMAP are always normal.
747 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
748 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
749 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
750 * mapping will always honor the rule
752 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
754 * And for normal mappings this is false.
756 * This restricts such mappings to be a linear translation from virtual address
757 * to pfn. To get around this restriction, we allow arbitrary mappings so long
758 * as the vma is not a COW mapping; in that case, we know that all ptes are
759 * special (because none can have been COWed).
762 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
764 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
765 * page" backing, however the difference is that _all_ pages with a struct
766 * page (that is, those where pfn_valid is true) are refcounted and considered
767 * normal pages by the VM. The disadvantage is that pages are refcounted
768 * (which can be slower and simply not an option for some PFNMAP users). The
769 * advantage is that we don't have to follow the strict linearity rule of
770 * PFNMAP mappings in order to support COWable mappings.
773 #ifdef __HAVE_ARCH_PTE_SPECIAL
774 # define HAVE_PTE_SPECIAL 1
776 # define HAVE_PTE_SPECIAL 0
778 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
781 unsigned long pfn = pte_pfn(pte);
783 if (HAVE_PTE_SPECIAL) {
784 if (likely(!pte_special(pte)))
786 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
788 if (!is_zero_pfn(pfn))
789 print_bad_pte(vma, addr, pte, NULL);
793 /* !HAVE_PTE_SPECIAL case follows: */
795 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
796 if (vma->vm_flags & VM_MIXEDMAP) {
802 off = (addr - vma->vm_start) >> PAGE_SHIFT;
803 if (pfn == vma->vm_pgoff + off)
805 if (!is_cow_mapping(vma->vm_flags))
810 if (is_zero_pfn(pfn))
813 if (unlikely(pfn > highest_memmap_pfn)) {
814 print_bad_pte(vma, addr, pte, NULL);
819 * NOTE! We still have PageReserved() pages in the page tables.
820 * eg. VDSO mappings can cause them to exist.
823 return pfn_to_page(pfn);
827 * copy one vm_area from one task to the other. Assumes the page tables
828 * already present in the new task to be cleared in the whole range
829 * covered by this vma.
832 static inline unsigned long
833 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
834 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
835 unsigned long addr, int *rss)
837 unsigned long vm_flags = vma->vm_flags;
838 pte_t pte = *src_pte;
841 /* pte contains position in swap or file, so copy. */
842 if (unlikely(!pte_present(pte))) {
843 if (!pte_file(pte)) {
844 swp_entry_t entry = pte_to_swp_entry(pte);
846 if (swap_duplicate(entry) < 0)
849 /* make sure dst_mm is on swapoff's mmlist. */
850 if (unlikely(list_empty(&dst_mm->mmlist))) {
851 spin_lock(&mmlist_lock);
852 if (list_empty(&dst_mm->mmlist))
853 list_add(&dst_mm->mmlist,
855 spin_unlock(&mmlist_lock);
857 if (likely(!non_swap_entry(entry)))
859 else if (is_migration_entry(entry)) {
860 page = migration_entry_to_page(entry);
867 if (is_write_migration_entry(entry) &&
868 is_cow_mapping(vm_flags)) {
870 * COW mappings require pages in both
871 * parent and child to be set to read.
873 make_migration_entry_read(&entry);
874 pte = swp_entry_to_pte(entry);
875 set_pte_at(src_mm, addr, src_pte, pte);
883 * If it's a COW mapping, write protect it both
884 * in the parent and the child
886 if (is_cow_mapping(vm_flags)) {
887 ptep_set_wrprotect(src_mm, addr, src_pte);
888 pte = pte_wrprotect(pte);
892 * If it's a shared mapping, mark it clean in
895 if (vm_flags & VM_SHARED)
896 pte = pte_mkclean(pte);
897 pte = pte_mkold(pte);
899 page = vm_normal_page(vma, addr, pte);
910 set_pte_at(dst_mm, addr, dst_pte, pte);
914 int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
915 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
916 unsigned long addr, unsigned long end)
918 pte_t *orig_src_pte, *orig_dst_pte;
919 pte_t *src_pte, *dst_pte;
920 spinlock_t *src_ptl, *dst_ptl;
922 int rss[NR_MM_COUNTERS];
923 swp_entry_t entry = (swp_entry_t){0};
928 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
931 src_pte = pte_offset_map(src_pmd, addr);
932 src_ptl = pte_lockptr(src_mm, src_pmd);
933 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
934 orig_src_pte = src_pte;
935 orig_dst_pte = dst_pte;
936 arch_enter_lazy_mmu_mode();
940 * We are holding two locks at this point - either of them
941 * could generate latencies in another task on another CPU.
943 if (progress >= 32) {
945 if (need_resched() ||
946 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
949 if (pte_none(*src_pte)) {
953 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
958 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
960 arch_leave_lazy_mmu_mode();
961 spin_unlock(src_ptl);
962 pte_unmap(orig_src_pte);
963 add_mm_rss_vec(dst_mm, rss);
964 pte_unmap_unlock(orig_dst_pte, dst_ptl);
968 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
977 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
978 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
979 unsigned long addr, unsigned long end)
981 pmd_t *src_pmd, *dst_pmd;
984 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
987 src_pmd = pmd_offset(src_pud, addr);
989 next = pmd_addr_end(addr, end);
990 if (pmd_trans_huge(*src_pmd)) {
992 VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
993 err = copy_huge_pmd(dst_mm, src_mm,
994 dst_pmd, src_pmd, addr, vma);
1001 if (pmd_none_or_clear_bad(src_pmd))
1003 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
1006 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
1010 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1011 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
1012 unsigned long addr, unsigned long end)
1014 pud_t *src_pud, *dst_pud;
1017 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
1020 src_pud = pud_offset(src_pgd, addr);
1022 next = pud_addr_end(addr, end);
1023 if (pud_none_or_clear_bad(src_pud))
1025 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
1028 } while (dst_pud++, src_pud++, addr = next, addr != end);
1032 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1033 struct vm_area_struct *vma)
1035 pgd_t *src_pgd, *dst_pgd;
1037 unsigned long addr = vma->vm_start;
1038 unsigned long end = vma->vm_end;
1039 unsigned long mmun_start; /* For mmu_notifiers */
1040 unsigned long mmun_end; /* For mmu_notifiers */
1045 * Don't copy ptes where a page fault will fill them correctly.
1046 * Fork becomes much lighter when there are big shared or private
1047 * readonly mappings. The tradeoff is that copy_page_range is more
1048 * efficient than faulting.
1050 if (!(vma->vm_flags & (VM_HUGETLB | VM_NONLINEAR |
1051 VM_PFNMAP | VM_MIXEDMAP))) {
1056 if (is_vm_hugetlb_page(vma))
1057 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
1059 if (unlikely(vma->vm_flags & VM_PFNMAP)) {
1061 * We do not free on error cases below as remove_vma
1062 * gets called on error from higher level routine
1064 ret = track_pfn_copy(vma);
1070 * We need to invalidate the secondary MMU mappings only when
1071 * there could be a permission downgrade on the ptes of the
1072 * parent mm. And a permission downgrade will only happen if
1073 * is_cow_mapping() returns true.
1075 is_cow = is_cow_mapping(vma->vm_flags);
1079 mmu_notifier_invalidate_range_start(src_mm, mmun_start,
1083 dst_pgd = pgd_offset(dst_mm, addr);
1084 src_pgd = pgd_offset(src_mm, addr);
1086 next = pgd_addr_end(addr, end);
1087 if (pgd_none_or_clear_bad(src_pgd))
1089 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
1090 vma, addr, next))) {
1094 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
1097 mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end);
1101 static unsigned long zap_pte_range(struct mmu_gather *tlb,
1102 struct vm_area_struct *vma, pmd_t *pmd,
1103 unsigned long addr, unsigned long end,
1104 struct zap_details *details)
1106 struct mm_struct *mm = tlb->mm;
1107 int force_flush = 0;
1108 int rss[NR_MM_COUNTERS];
1115 start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
1117 arch_enter_lazy_mmu_mode();
1120 if (pte_none(ptent)) {
1124 if (pte_present(ptent)) {
1127 page = vm_normal_page(vma, addr, ptent);
1128 if (unlikely(details) && page) {
1130 * unmap_shared_mapping_pages() wants to
1131 * invalidate cache without truncating:
1132 * unmap shared but keep private pages.
1134 if (details->check_mapping &&
1135 details->check_mapping != page->mapping)
1138 * Each page->index must be checked when
1139 * invalidating or truncating nonlinear.
1141 if (details->nonlinear_vma &&
1142 (page->index < details->first_index ||
1143 page->index > details->last_index))
1146 ptent = ptep_get_and_clear_full(mm, addr, pte,
1148 tlb_remove_tlb_entry(tlb, pte, addr);
1149 if (unlikely(!page))
1151 if (unlikely(details) && details->nonlinear_vma
1152 && linear_page_index(details->nonlinear_vma,
1153 addr) != page->index)
1154 set_pte_at(mm, addr, pte,
1155 pgoff_to_pte(page->index));
1157 rss[MM_ANONPAGES]--;
1159 if (pte_dirty(ptent))
1160 set_page_dirty(page);
1161 if (pte_young(ptent) &&
1162 likely(!VM_SequentialReadHint(vma)))
1163 mark_page_accessed(page);
1164 rss[MM_FILEPAGES]--;
1166 page_remove_rmap(page);
1167 if (unlikely(page_mapcount(page) < 0))
1168 print_bad_pte(vma, addr, ptent, page);
1169 force_flush = !__tlb_remove_page(tlb, page);
1175 * If details->check_mapping, we leave swap entries;
1176 * if details->nonlinear_vma, we leave file entries.
1178 if (unlikely(details))
1180 if (pte_file(ptent)) {
1181 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
1182 print_bad_pte(vma, addr, ptent, NULL);
1184 swp_entry_t entry = pte_to_swp_entry(ptent);
1186 if (!non_swap_entry(entry))
1188 else if (is_migration_entry(entry)) {
1191 page = migration_entry_to_page(entry);
1194 rss[MM_ANONPAGES]--;
1196 rss[MM_FILEPAGES]--;
1198 if (unlikely(!free_swap_and_cache(entry)))
1199 print_bad_pte(vma, addr, ptent, NULL);
1201 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
1202 } while (pte++, addr += PAGE_SIZE, addr != end);
1204 add_mm_rss_vec(mm, rss);
1205 arch_leave_lazy_mmu_mode();
1206 pte_unmap_unlock(start_pte, ptl);
1209 * mmu_gather ran out of room to batch pages, we break out of
1210 * the PTE lock to avoid doing the potential expensive TLB invalidate
1211 * and page-free while holding it.
1216 #ifdef HAVE_GENERIC_MMU_GATHER
1228 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
1229 struct vm_area_struct *vma, pud_t *pud,
1230 unsigned long addr, unsigned long end,
1231 struct zap_details *details)
1236 pmd = pmd_offset(pud, addr);
1238 next = pmd_addr_end(addr, end);
1239 if (pmd_trans_huge(*pmd)) {
1240 if (next - addr != HPAGE_PMD_SIZE) {
1241 #ifdef CONFIG_DEBUG_VM
1242 if (!rwsem_is_locked(&tlb->mm->mmap_sem)) {
1243 pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n",
1244 __func__, addr, end,
1250 split_huge_page_pmd(vma, addr, pmd);
1251 } else if (zap_huge_pmd(tlb, vma, pmd, addr))
1256 * Here there can be other concurrent MADV_DONTNEED or
1257 * trans huge page faults running, and if the pmd is
1258 * none or trans huge it can change under us. This is
1259 * because MADV_DONTNEED holds the mmap_sem in read
1262 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
1264 next = zap_pte_range(tlb, vma, pmd, addr, next, details);
1267 } while (pmd++, addr = next, addr != end);
1272 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1273 struct vm_area_struct *vma, pgd_t *pgd,
1274 unsigned long addr, unsigned long end,
1275 struct zap_details *details)
1280 pud = pud_offset(pgd, addr);
1282 next = pud_addr_end(addr, end);
1283 if (pud_none_or_clear_bad(pud))
1285 next = zap_pmd_range(tlb, vma, pud, addr, next, details);
1286 } while (pud++, addr = next, addr != end);
1291 static void unmap_page_range(struct mmu_gather *tlb,
1292 struct vm_area_struct *vma,
1293 unsigned long addr, unsigned long end,
1294 struct zap_details *details)
1299 if (details && !details->check_mapping && !details->nonlinear_vma)
1302 BUG_ON(addr >= end);
1303 mem_cgroup_uncharge_start();
1304 tlb_start_vma(tlb, vma);
1305 pgd = pgd_offset(vma->vm_mm, addr);
1307 next = pgd_addr_end(addr, end);
1308 if (pgd_none_or_clear_bad(pgd))
1310 next = zap_pud_range(tlb, vma, pgd, addr, next, details);
1311 } while (pgd++, addr = next, addr != end);
1312 tlb_end_vma(tlb, vma);
1313 mem_cgroup_uncharge_end();
1317 static void unmap_single_vma(struct mmu_gather *tlb,
1318 struct vm_area_struct *vma, unsigned long start_addr,
1319 unsigned long end_addr,
1320 struct zap_details *details)
1322 unsigned long start = max(vma->vm_start, start_addr);
1325 if (start >= vma->vm_end)
1327 end = min(vma->vm_end, end_addr);
1328 if (end <= vma->vm_start)
1332 uprobe_munmap(vma, start, end);
1334 if (unlikely(vma->vm_flags & VM_PFNMAP))
1335 untrack_pfn(vma, 0, 0);
1338 if (unlikely(is_vm_hugetlb_page(vma))) {
1340 * It is undesirable to test vma->vm_file as it
1341 * should be non-null for valid hugetlb area.
1342 * However, vm_file will be NULL in the error
1343 * cleanup path of do_mmap_pgoff. When
1344 * hugetlbfs ->mmap method fails,
1345 * do_mmap_pgoff() nullifies vma->vm_file
1346 * before calling this function to clean up.
1347 * Since no pte has actually been setup, it is
1348 * safe to do nothing in this case.
1351 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
1352 __unmap_hugepage_range_final(tlb, vma, start, end, NULL);
1353 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
1356 unmap_page_range(tlb, vma, start, end, details);
1361 * unmap_vmas - unmap a range of memory covered by a list of vma's
1362 * @tlb: address of the caller's struct mmu_gather
1363 * @vma: the starting vma
1364 * @start_addr: virtual address at which to start unmapping
1365 * @end_addr: virtual address at which to end unmapping
1367 * Unmap all pages in the vma list.
1369 * Only addresses between `start' and `end' will be unmapped.
1371 * The VMA list must be sorted in ascending virtual address order.
1373 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1374 * range after unmap_vmas() returns. So the only responsibility here is to
1375 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1376 * drops the lock and schedules.
1378 void unmap_vmas(struct mmu_gather *tlb,
1379 struct vm_area_struct *vma, unsigned long start_addr,
1380 unsigned long end_addr)
1382 struct mm_struct *mm = vma->vm_mm;
1384 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1385 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
1386 unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
1387 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1391 * zap_page_range - remove user pages in a given range
1392 * @vma: vm_area_struct holding the applicable pages
1393 * @start: starting address of pages to zap
1394 * @size: number of bytes to zap
1395 * @details: details of nonlinear truncation or shared cache invalidation
1397 * Caller must protect the VMA list
1399 void zap_page_range(struct vm_area_struct *vma, unsigned long start,
1400 unsigned long size, struct zap_details *details)
1402 struct mm_struct *mm = vma->vm_mm;
1403 struct mmu_gather tlb;
1404 unsigned long end = start + size;
1407 tlb_gather_mmu(&tlb, mm, 0);
1408 update_hiwater_rss(mm);
1409 mmu_notifier_invalidate_range_start(mm, start, end);
1410 for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
1411 unmap_single_vma(&tlb, vma, start, end, details);
1412 mmu_notifier_invalidate_range_end(mm, start, end);
1413 tlb_finish_mmu(&tlb, start, end);
1417 * zap_page_range_single - remove user pages in a given range
1418 * @vma: vm_area_struct holding the applicable pages
1419 * @address: starting address of pages to zap
1420 * @size: number of bytes to zap
1421 * @details: details of nonlinear truncation or shared cache invalidation
1423 * The range must fit into one VMA.
1425 static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
1426 unsigned long size, struct zap_details *details)
1428 struct mm_struct *mm = vma->vm_mm;
1429 struct mmu_gather tlb;
1430 unsigned long end = address + size;
1433 tlb_gather_mmu(&tlb, mm, 0);
1434 update_hiwater_rss(mm);
1435 mmu_notifier_invalidate_range_start(mm, address, end);
1436 unmap_single_vma(&tlb, vma, address, end, details);
1437 mmu_notifier_invalidate_range_end(mm, address, end);
1438 tlb_finish_mmu(&tlb, address, end);
1442 * zap_vma_ptes - remove ptes mapping the vma
1443 * @vma: vm_area_struct holding ptes to be zapped
1444 * @address: starting address of pages to zap
1445 * @size: number of bytes to zap
1447 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1449 * The entire address range must be fully contained within the vma.
1451 * Returns 0 if successful.
1453 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1456 if (address < vma->vm_start || address + size > vma->vm_end ||
1457 !(vma->vm_flags & VM_PFNMAP))
1459 zap_page_range_single(vma, address, size, NULL);
1462 EXPORT_SYMBOL_GPL(zap_vma_ptes);
1465 * follow_page - look up a page descriptor from a user-virtual address
1466 * @vma: vm_area_struct mapping @address
1467 * @address: virtual address to look up
1468 * @flags: flags modifying lookup behaviour
1470 * @flags can have FOLL_ flags set, defined in <linux/mm.h>
1472 * Returns the mapped (struct page *), %NULL if no mapping exists, or
1473 * an error pointer if there is a mapping to something not represented
1474 * by a page descriptor (see also vm_normal_page()).
1476 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1485 struct mm_struct *mm = vma->vm_mm;
1487 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1488 if (!IS_ERR(page)) {
1489 BUG_ON(flags & FOLL_GET);
1494 pgd = pgd_offset(mm, address);
1495 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1498 pud = pud_offset(pgd, address);
1501 if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
1502 BUG_ON(flags & FOLL_GET);
1503 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1506 if (unlikely(pud_bad(*pud)))
1509 pmd = pmd_offset(pud, address);
1512 if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) {
1513 BUG_ON(flags & FOLL_GET);
1514 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1517 if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
1519 if (pmd_trans_huge(*pmd)) {
1520 if (flags & FOLL_SPLIT) {
1521 split_huge_page_pmd(vma, address, pmd);
1522 goto split_fallthrough;
1524 spin_lock(&mm->page_table_lock);
1525 if (likely(pmd_trans_huge(*pmd))) {
1526 if (unlikely(pmd_trans_splitting(*pmd))) {
1527 spin_unlock(&mm->page_table_lock);
1528 wait_split_huge_page(vma->anon_vma, pmd);
1530 page = follow_trans_huge_pmd(vma, address,
1532 spin_unlock(&mm->page_table_lock);
1536 spin_unlock(&mm->page_table_lock);
1540 if (unlikely(pmd_bad(*pmd)))
1543 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1546 if (!pte_present(pte))
1548 if ((flags & FOLL_NUMA) && pte_numa(pte))
1550 if ((flags & FOLL_WRITE) && !pte_write(pte))
1553 page = vm_normal_page(vma, address, pte);
1554 if (unlikely(!page)) {
1555 if ((flags & FOLL_DUMP) ||
1556 !is_zero_pfn(pte_pfn(pte)))
1558 page = pte_page(pte);
1561 if (flags & FOLL_GET)
1562 get_page_foll(page);
1563 if (flags & FOLL_TOUCH) {
1564 if ((flags & FOLL_WRITE) &&
1565 !pte_dirty(pte) && !PageDirty(page))
1566 set_page_dirty(page);
1568 * pte_mkyoung() would be more correct here, but atomic care
1569 * is needed to avoid losing the dirty bit: it is easier to use
1570 * mark_page_accessed().
1572 mark_page_accessed(page);
1574 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1576 * The preliminary mapping check is mainly to avoid the
1577 * pointless overhead of lock_page on the ZERO_PAGE
1578 * which might bounce very badly if there is contention.
1580 * If the page is already locked, we don't need to
1581 * handle it now - vmscan will handle it later if and
1582 * when it attempts to reclaim the page.
1584 if (page->mapping && trylock_page(page)) {
1585 lru_add_drain(); /* push cached pages to LRU */
1587 * Because we lock page here, and migration is
1588 * blocked by the pte's page reference, and we
1589 * know the page is still mapped, we don't even
1590 * need to check for file-cache page truncation.
1592 mlock_vma_page(page);
1597 pte_unmap_unlock(ptep, ptl);
1602 pte_unmap_unlock(ptep, ptl);
1603 return ERR_PTR(-EFAULT);
1606 pte_unmap_unlock(ptep, ptl);
1612 * When core dumping an enormous anonymous area that nobody
1613 * has touched so far, we don't want to allocate unnecessary pages or
1614 * page tables. Return error instead of NULL to skip handle_mm_fault,
1615 * then get_dump_page() will return NULL to leave a hole in the dump.
1616 * But we can only make this optimization where a hole would surely
1617 * be zero-filled if handle_mm_fault() actually did handle it.
1619 if ((flags & FOLL_DUMP) &&
1620 (!vma->vm_ops || !vma->vm_ops->fault))
1621 return ERR_PTR(-EFAULT);
1625 static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
1627 return stack_guard_page_start(vma, addr) ||
1628 stack_guard_page_end(vma, addr+PAGE_SIZE);
1632 * __get_user_pages() - pin user pages in memory
1633 * @tsk: task_struct of target task
1634 * @mm: mm_struct of target mm
1635 * @start: starting user address
1636 * @nr_pages: number of pages from start to pin
1637 * @gup_flags: flags modifying pin behaviour
1638 * @pages: array that receives pointers to the pages pinned.
1639 * Should be at least nr_pages long. Or NULL, if caller
1640 * only intends to ensure the pages are faulted in.
1641 * @vmas: array of pointers to vmas corresponding to each page.
1642 * Or NULL if the caller does not require them.
1643 * @nonblocking: whether waiting for disk IO or mmap_sem contention
1645 * Returns number of pages pinned. This may be fewer than the number
1646 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1647 * were pinned, returns -errno. Each page returned must be released
1648 * with a put_page() call when it is finished with. vmas will only
1649 * remain valid while mmap_sem is held.
1651 * Must be called with mmap_sem held for read or write.
1653 * __get_user_pages walks a process's page tables and takes a reference to
1654 * each struct page that each user address corresponds to at a given
1655 * instant. That is, it takes the page that would be accessed if a user
1656 * thread accesses the given user virtual address at that instant.
1658 * This does not guarantee that the page exists in the user mappings when
1659 * __get_user_pages returns, and there may even be a completely different
1660 * page there in some cases (eg. if mmapped pagecache has been invalidated
1661 * and subsequently re faulted). However it does guarantee that the page
1662 * won't be freed completely. And mostly callers simply care that the page
1663 * contains data that was valid *at some point in time*. Typically, an IO
1664 * or similar operation cannot guarantee anything stronger anyway because
1665 * locks can't be held over the syscall boundary.
1667 * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
1668 * the page is written to, set_page_dirty (or set_page_dirty_lock, as
1669 * appropriate) must be called after the page is finished with, and
1670 * before put_page is called.
1672 * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
1673 * or mmap_sem contention, and if waiting is needed to pin all pages,
1674 * *@nonblocking will be set to 0.
1676 * In most cases, get_user_pages or get_user_pages_fast should be used
1677 * instead of __get_user_pages. __get_user_pages should be used only if
1678 * you need some special @gup_flags.
1680 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1681 unsigned long start, int nr_pages, unsigned int gup_flags,
1682 struct page **pages, struct vm_area_struct **vmas,
1686 unsigned long vm_flags;
1691 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1694 * Require read or write permissions.
1695 * If FOLL_FORCE is set, we only require the "MAY" flags.
1697 vm_flags = (gup_flags & FOLL_WRITE) ?
1698 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1699 vm_flags &= (gup_flags & FOLL_FORCE) ?
1700 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1703 * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
1704 * would be called on PROT_NONE ranges. We must never invoke
1705 * handle_mm_fault on PROT_NONE ranges or the NUMA hinting
1706 * page faults would unprotect the PROT_NONE ranges if
1707 * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd
1708 * bitflag. So to avoid that, don't set FOLL_NUMA if
1709 * FOLL_FORCE is set.
1711 if (!(gup_flags & FOLL_FORCE))
1712 gup_flags |= FOLL_NUMA;
1717 struct vm_area_struct *vma;
1719 vma = find_extend_vma(mm, start);
1720 if (!vma && in_gate_area(mm, start)) {
1721 unsigned long pg = start & PAGE_MASK;
1727 /* user gate pages are read-only */
1728 if (gup_flags & FOLL_WRITE)
1729 return i ? : -EFAULT;
1731 pgd = pgd_offset_k(pg);
1733 pgd = pgd_offset_gate(mm, pg);
1734 BUG_ON(pgd_none(*pgd));
1735 pud = pud_offset(pgd, pg);
1736 BUG_ON(pud_none(*pud));
1737 pmd = pmd_offset(pud, pg);
1739 return i ? : -EFAULT;
1740 VM_BUG_ON(pmd_trans_huge(*pmd));
1741 pte = pte_offset_map(pmd, pg);
1742 if (pte_none(*pte)) {
1744 return i ? : -EFAULT;
1746 vma = get_gate_vma(mm);
1750 page = vm_normal_page(vma, start, *pte);
1752 if (!(gup_flags & FOLL_DUMP) &&
1753 is_zero_pfn(pte_pfn(*pte)))
1754 page = pte_page(*pte);
1757 return i ? : -EFAULT;
1768 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1769 !(vm_flags & vma->vm_flags))
1770 return i ? : -EFAULT;
1772 if (is_vm_hugetlb_page(vma)) {
1773 i = follow_hugetlb_page(mm, vma, pages, vmas,
1774 &start, &nr_pages, i, gup_flags);
1780 unsigned int foll_flags = gup_flags;
1783 * If we have a pending SIGKILL, don't keep faulting
1784 * pages and potentially allocating memory.
1786 if (unlikely(fatal_signal_pending(current)))
1787 return i ? i : -ERESTARTSYS;
1790 while (!(page = follow_page(vma, start, foll_flags))) {
1792 unsigned int fault_flags = 0;
1794 /* For mlock, just skip the stack guard page. */
1795 if (foll_flags & FOLL_MLOCK) {
1796 if (stack_guard_page(vma, start))
1799 if (foll_flags & FOLL_WRITE)
1800 fault_flags |= FAULT_FLAG_WRITE;
1802 fault_flags |= FAULT_FLAG_ALLOW_RETRY;
1803 if (foll_flags & FOLL_NOWAIT)
1804 fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT);
1806 ret = handle_mm_fault(mm, vma, start,
1809 if (ret & VM_FAULT_ERROR) {
1810 if (ret & VM_FAULT_OOM)
1811 return i ? i : -ENOMEM;
1812 if (ret & (VM_FAULT_HWPOISON |
1813 VM_FAULT_HWPOISON_LARGE)) {
1816 else if (gup_flags & FOLL_HWPOISON)
1821 if (ret & VM_FAULT_SIGBUS)
1822 return i ? i : -EFAULT;
1827 if (ret & VM_FAULT_MAJOR)
1833 if (ret & VM_FAULT_RETRY) {
1840 * The VM_FAULT_WRITE bit tells us that
1841 * do_wp_page has broken COW when necessary,
1842 * even if maybe_mkwrite decided not to set
1843 * pte_write. We can thus safely do subsequent
1844 * page lookups as if they were reads. But only
1845 * do so when looping for pte_write is futile:
1846 * in some cases userspace may also be wanting
1847 * to write to the gotten user page, which a
1848 * read fault here might prevent (a readonly
1849 * page might get reCOWed by userspace write).
1851 if ((ret & VM_FAULT_WRITE) &&
1852 !(vma->vm_flags & VM_WRITE))
1853 foll_flags &= ~FOLL_WRITE;
1858 return i ? i : PTR_ERR(page);
1862 flush_anon_page(vma, page, start);
1863 flush_dcache_page(page);
1871 } while (nr_pages && start < vma->vm_end);
1875 EXPORT_SYMBOL(__get_user_pages);
1878 * fixup_user_fault() - manually resolve a user page fault
1879 * @tsk: the task_struct to use for page fault accounting, or
1880 * NULL if faults are not to be recorded.
1881 * @mm: mm_struct of target mm
1882 * @address: user address
1883 * @fault_flags:flags to pass down to handle_mm_fault()
1885 * This is meant to be called in the specific scenario where for locking reasons
1886 * we try to access user memory in atomic context (within a pagefault_disable()
1887 * section), this returns -EFAULT, and we want to resolve the user fault before
1890 * Typically this is meant to be used by the futex code.
1892 * The main difference with get_user_pages() is that this function will
1893 * unconditionally call handle_mm_fault() which will in turn perform all the
1894 * necessary SW fixup of the dirty and young bits in the PTE, while
1895 * handle_mm_fault() only guarantees to update these in the struct page.
1897 * This is important for some architectures where those bits also gate the
1898 * access permission to the page because they are maintained in software. On
1899 * such architectures, gup() will not be enough to make a subsequent access
1902 * This should be called with the mm_sem held for read.
1904 int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1905 unsigned long address, unsigned int fault_flags)
1907 struct vm_area_struct *vma;
1910 vma = find_extend_vma(mm, address);
1911 if (!vma || address < vma->vm_start)
1914 ret = handle_mm_fault(mm, vma, address, fault_flags);
1915 if (ret & VM_FAULT_ERROR) {
1916 if (ret & VM_FAULT_OOM)
1918 if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
1920 if (ret & VM_FAULT_SIGBUS)
1925 if (ret & VM_FAULT_MAJOR)
1934 * get_user_pages() - pin user pages in memory
1935 * @tsk: the task_struct to use for page fault accounting, or
1936 * NULL if faults are not to be recorded.
1937 * @mm: mm_struct of target mm
1938 * @start: starting user address
1939 * @nr_pages: number of pages from start to pin
1940 * @write: whether pages will be written to by the caller
1941 * @force: whether to force write access even if user mapping is
1942 * readonly. This will result in the page being COWed even
1943 * in MAP_SHARED mappings. You do not want this.
1944 * @pages: array that receives pointers to the pages pinned.
1945 * Should be at least nr_pages long. Or NULL, if caller
1946 * only intends to ensure the pages are faulted in.
1947 * @vmas: array of pointers to vmas corresponding to each page.
1948 * Or NULL if the caller does not require them.
1950 * Returns number of pages pinned. This may be fewer than the number
1951 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1952 * were pinned, returns -errno. Each page returned must be released
1953 * with a put_page() call when it is finished with. vmas will only
1954 * remain valid while mmap_sem is held.
1956 * Must be called with mmap_sem held for read or write.
1958 * get_user_pages walks a process's page tables and takes a reference to
1959 * each struct page that each user address corresponds to at a given
1960 * instant. That is, it takes the page that would be accessed if a user
1961 * thread accesses the given user virtual address at that instant.
1963 * This does not guarantee that the page exists in the user mappings when
1964 * get_user_pages returns, and there may even be a completely different
1965 * page there in some cases (eg. if mmapped pagecache has been invalidated
1966 * and subsequently re faulted). However it does guarantee that the page
1967 * won't be freed completely. And mostly callers simply care that the page
1968 * contains data that was valid *at some point in time*. Typically, an IO
1969 * or similar operation cannot guarantee anything stronger anyway because
1970 * locks can't be held over the syscall boundary.
1972 * If write=0, the page must not be written to. If the page is written to,
1973 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1974 * after the page is finished with, and before put_page is called.
1976 * get_user_pages is typically used for fewer-copy IO operations, to get a
1977 * handle on the memory by some means other than accesses via the user virtual
1978 * addresses. The pages may be submitted for DMA to devices or accessed via
1979 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1980 * use the correct cache flushing APIs.
1982 * See also get_user_pages_fast, for performance critical applications.
1984 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1985 unsigned long start, int nr_pages, int write, int force,
1986 struct page **pages, struct vm_area_struct **vmas)
1988 int flags = FOLL_TOUCH;
1993 flags |= FOLL_WRITE;
1995 flags |= FOLL_FORCE;
1997 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
2000 EXPORT_SYMBOL(get_user_pages);
2003 * get_dump_page() - pin user page in memory while writing it to core dump
2004 * @addr: user address
2006 * Returns struct page pointer of user page pinned for dump,
2007 * to be freed afterwards by page_cache_release() or put_page().
2009 * Returns NULL on any kind of failure - a hole must then be inserted into
2010 * the corefile, to preserve alignment with its headers; and also returns
2011 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
2012 * allowing a hole to be left in the corefile to save diskspace.
2014 * Called without mmap_sem, but after all other threads have been killed.
2016 #ifdef CONFIG_ELF_CORE
2017 struct page *get_dump_page(unsigned long addr)
2019 struct vm_area_struct *vma;
2022 if (__get_user_pages(current, current->mm, addr, 1,
2023 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
2026 flush_cache_page(vma, addr, page_to_pfn(page));
2029 #endif /* CONFIG_ELF_CORE */
2031 pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
2034 pgd_t * pgd = pgd_offset(mm, addr);
2035 pud_t * pud = pud_alloc(mm, pgd, addr);
2037 pmd_t * pmd = pmd_alloc(mm, pud, addr);
2039 VM_BUG_ON(pmd_trans_huge(*pmd));
2040 return pte_alloc_map_lock(mm, pmd, addr, ptl);
2047 * This is the old fallback for page remapping.
2049 * For historical reasons, it only allows reserved pages. Only
2050 * old drivers should use this, and they needed to mark their
2051 * pages reserved for the old functions anyway.
2053 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
2054 struct page *page, pgprot_t prot)
2056 struct mm_struct *mm = vma->vm_mm;
2065 flush_dcache_page(page);
2066 pte = get_locked_pte(mm, addr, &ptl);
2070 if (!pte_none(*pte))
2073 /* Ok, finally just insert the thing.. */
2075 inc_mm_counter_fast(mm, MM_FILEPAGES);
2076 page_add_file_rmap(page);
2077 set_pte_at(mm, addr, pte, mk_pte(page, prot));
2080 pte_unmap_unlock(pte, ptl);
2083 pte_unmap_unlock(pte, ptl);
2089 * vm_insert_page - insert single page into user vma
2090 * @vma: user vma to map to
2091 * @addr: target user address of this page
2092 * @page: source kernel page
2094 * This allows drivers to insert individual pages they've allocated
2097 * The page has to be a nice clean _individual_ kernel allocation.
2098 * If you allocate a compound page, you need to have marked it as
2099 * such (__GFP_COMP), or manually just split the page up yourself
2100 * (see split_page()).
2102 * NOTE! Traditionally this was done with "remap_pfn_range()" which
2103 * took an arbitrary page protection parameter. This doesn't allow
2104 * that. Your vma protection will have to be set up correctly, which
2105 * means that if you want a shared writable mapping, you'd better
2106 * ask for a shared writable mapping!
2108 * The page does not need to be reserved.
2110 * Usually this function is called from f_op->mmap() handler
2111 * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
2112 * Caller must set VM_MIXEDMAP on vma if it wants to call this
2113 * function from other places, for example from page-fault handler.
2115 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
2118 if (addr < vma->vm_start || addr >= vma->vm_end)
2120 if (!page_count(page))
2122 if (!(vma->vm_flags & VM_MIXEDMAP)) {
2123 BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem));
2124 BUG_ON(vma->vm_flags & VM_PFNMAP);
2125 vma->vm_flags |= VM_MIXEDMAP;
2127 return insert_page(vma, addr, page, vma->vm_page_prot);
2129 EXPORT_SYMBOL(vm_insert_page);
2131 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2132 unsigned long pfn, pgprot_t prot)
2134 struct mm_struct *mm = vma->vm_mm;
2140 pte = get_locked_pte(mm, addr, &ptl);
2144 if (!pte_none(*pte))
2147 /* Ok, finally just insert the thing.. */
2148 entry = pte_mkspecial(pfn_pte(pfn, prot));
2149 set_pte_at(mm, addr, pte, entry);
2150 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
2154 pte_unmap_unlock(pte, ptl);
2160 * vm_insert_pfn - insert single pfn into user vma
2161 * @vma: user vma to map to
2162 * @addr: target user address of this page
2163 * @pfn: source kernel pfn
2165 * Similar to vm_insert_page, this allows drivers to insert individual pages
2166 * they've allocated into a user vma. Same comments apply.
2168 * This function should only be called from a vm_ops->fault handler, and
2169 * in that case the handler should return NULL.
2171 * vma cannot be a COW mapping.
2173 * As this is called only for pages that do not currently exist, we
2174 * do not need to flush old virtual caches or the TLB.
2176 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2180 pgprot_t pgprot = vma->vm_page_prot;
2182 * Technically, architectures with pte_special can avoid all these
2183 * restrictions (same for remap_pfn_range). However we would like
2184 * consistency in testing and feature parity among all, so we should
2185 * try to keep these invariants in place for everybody.
2187 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
2188 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
2189 (VM_PFNMAP|VM_MIXEDMAP));
2190 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
2191 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
2193 if (addr < vma->vm_start || addr >= vma->vm_end)
2195 if (track_pfn_insert(vma, &pgprot, pfn))
2198 ret = insert_pfn(vma, addr, pfn, pgprot);
2202 EXPORT_SYMBOL(vm_insert_pfn);
2204 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2207 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
2209 if (addr < vma->vm_start || addr >= vma->vm_end)
2213 * If we don't have pte special, then we have to use the pfn_valid()
2214 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
2215 * refcount the page if pfn_valid is true (hence insert_page rather
2216 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
2217 * without pte special, it would there be refcounted as a normal page.
2219 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
2222 page = pfn_to_page(pfn);
2223 return insert_page(vma, addr, page, vma->vm_page_prot);
2225 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
2227 EXPORT_SYMBOL(vm_insert_mixed);
2230 * maps a range of physical memory into the requested pages. the old
2231 * mappings are removed. any references to nonexistent pages results
2232 * in null mappings (currently treated as "copy-on-access")
2234 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
2235 unsigned long addr, unsigned long end,
2236 unsigned long pfn, pgprot_t prot)
2241 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
2244 arch_enter_lazy_mmu_mode();
2246 BUG_ON(!pte_none(*pte));
2247 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
2249 } while (pte++, addr += PAGE_SIZE, addr != end);
2250 arch_leave_lazy_mmu_mode();
2251 pte_unmap_unlock(pte - 1, ptl);
2255 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
2256 unsigned long addr, unsigned long end,
2257 unsigned long pfn, pgprot_t prot)
2262 pfn -= addr >> PAGE_SHIFT;
2263 pmd = pmd_alloc(mm, pud, addr);
2266 VM_BUG_ON(pmd_trans_huge(*pmd));
2268 next = pmd_addr_end(addr, end);
2269 if (remap_pte_range(mm, pmd, addr, next,
2270 pfn + (addr >> PAGE_SHIFT), prot))
2272 } while (pmd++, addr = next, addr != end);
2276 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
2277 unsigned long addr, unsigned long end,
2278 unsigned long pfn, pgprot_t prot)
2283 pfn -= addr >> PAGE_SHIFT;
2284 pud = pud_alloc(mm, pgd, addr);
2288 next = pud_addr_end(addr, end);
2289 if (remap_pmd_range(mm, pud, addr, next,
2290 pfn + (addr >> PAGE_SHIFT), prot))
2292 } while (pud++, addr = next, addr != end);
2297 * remap_pfn_range - remap kernel memory to userspace
2298 * @vma: user vma to map to
2299 * @addr: target user address to start at
2300 * @pfn: physical address of kernel memory
2301 * @size: size of map area
2302 * @prot: page protection flags for this mapping
2304 * Note: this is only safe if the mm semaphore is held when called.
2306 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
2307 unsigned long pfn, unsigned long size, pgprot_t prot)
2311 unsigned long end = addr + PAGE_ALIGN(size);
2312 struct mm_struct *mm = vma->vm_mm;
2316 * Physically remapped pages are special. Tell the
2317 * rest of the world about it:
2318 * VM_IO tells people not to look at these pages
2319 * (accesses can have side effects).
2320 * VM_PFNMAP tells the core MM that the base pages are just
2321 * raw PFN mappings, and do not have a "struct page" associated
2324 * Disable vma merging and expanding with mremap().
2326 * Omit vma from core dump, even when VM_IO turned off.
2328 * There's a horrible special case to handle copy-on-write
2329 * behaviour that some programs depend on. We mark the "original"
2330 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
2331 * See vm_normal_page() for details.
2333 if (is_cow_mapping(vma->vm_flags)) {
2334 if (addr != vma->vm_start || end != vma->vm_end)
2336 vma->vm_pgoff = pfn;
2339 err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
2343 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
2345 BUG_ON(addr >= end);
2346 pfn -= addr >> PAGE_SHIFT;
2347 pgd = pgd_offset(mm, addr);
2348 flush_cache_range(vma, addr, end);
2350 next = pgd_addr_end(addr, end);
2351 err = remap_pud_range(mm, pgd, addr, next,
2352 pfn + (addr >> PAGE_SHIFT), prot);
2355 } while (pgd++, addr = next, addr != end);
2358 untrack_pfn(vma, pfn, PAGE_ALIGN(size));
2362 EXPORT_SYMBOL(remap_pfn_range);
2364 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
2365 unsigned long addr, unsigned long end,
2366 pte_fn_t fn, void *data)
2371 spinlock_t *uninitialized_var(ptl);
2373 pte = (mm == &init_mm) ?
2374 pte_alloc_kernel(pmd, addr) :
2375 pte_alloc_map_lock(mm, pmd, addr, &ptl);
2379 BUG_ON(pmd_huge(*pmd));
2381 arch_enter_lazy_mmu_mode();
2383 token = pmd_pgtable(*pmd);
2386 err = fn(pte++, token, addr, data);
2389 } while (addr += PAGE_SIZE, addr != end);
2391 arch_leave_lazy_mmu_mode();
2394 pte_unmap_unlock(pte-1, ptl);
2398 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
2399 unsigned long addr, unsigned long end,
2400 pte_fn_t fn, void *data)
2406 BUG_ON(pud_huge(*pud));
2408 pmd = pmd_alloc(mm, pud, addr);
2412 next = pmd_addr_end(addr, end);
2413 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
2416 } while (pmd++, addr = next, addr != end);
2420 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
2421 unsigned long addr, unsigned long end,
2422 pte_fn_t fn, void *data)
2428 pud = pud_alloc(mm, pgd, addr);
2432 next = pud_addr_end(addr, end);
2433 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
2436 } while (pud++, addr = next, addr != end);
2441 * Scan a region of virtual memory, filling in page tables as necessary
2442 * and calling a provided function on each leaf page table.
2444 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2445 unsigned long size, pte_fn_t fn, void *data)
2449 unsigned long end = addr + size;
2452 BUG_ON(addr >= end);
2453 pgd = pgd_offset(mm, addr);
2455 next = pgd_addr_end(addr, end);
2456 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2459 } while (pgd++, addr = next, addr != end);
2463 EXPORT_SYMBOL_GPL(apply_to_page_range);
2466 * handle_pte_fault chooses page fault handler according to an entry
2467 * which was read non-atomically. Before making any commitment, on
2468 * those architectures or configurations (e.g. i386 with PAE) which
2469 * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
2470 * must check under lock before unmapping the pte and proceeding
2471 * (but do_wp_page is only called after already making such a check;
2472 * and do_anonymous_page can safely check later on).
2474 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2475 pte_t *page_table, pte_t orig_pte)
2478 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2479 if (sizeof(pte_t) > sizeof(unsigned long)) {
2480 spinlock_t *ptl = pte_lockptr(mm, pmd);
2482 same = pte_same(*page_table, orig_pte);
2486 pte_unmap(page_table);
2490 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2493 * If the source page was a PFN mapping, we don't have
2494 * a "struct page" for it. We do a best-effort copy by
2495 * just copying from the original user address. If that
2496 * fails, we just zero-fill it. Live with it.
2498 if (unlikely(!src)) {
2499 void *kaddr = kmap_atomic(dst);
2500 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2503 * This really shouldn't fail, because the page is there
2504 * in the page tables. But it might just be unreadable,
2505 * in which case we just give up and fill the result with
2508 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2510 kunmap_atomic(kaddr);
2511 flush_dcache_page(dst);
2513 copy_user_highpage(dst, src, va, vma);
2517 * This routine handles present pages, when users try to write
2518 * to a shared page. It is done by copying the page to a new address
2519 * and decrementing the shared-page counter for the old page.
2521 * Note that this routine assumes that the protection checks have been
2522 * done by the caller (the low-level page fault routine in most cases).
2523 * Thus we can safely just mark it writable once we've done any necessary
2526 * We also mark the page dirty at this point even though the page will
2527 * change only once the write actually happens. This avoids a few races,
2528 * and potentially makes it more efficient.
2530 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2531 * but allow concurrent faults), with pte both mapped and locked.
2532 * We return with mmap_sem still held, but pte unmapped and unlocked.
2534 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2535 unsigned long address, pte_t *page_table, pmd_t *pmd,
2536 spinlock_t *ptl, pte_t orig_pte)
2539 struct page *old_page, *new_page = NULL;
2542 int page_mkwrite = 0;
2543 struct page *dirty_page = NULL;
2544 unsigned long mmun_start = 0; /* For mmu_notifiers */
2545 unsigned long mmun_end = 0; /* For mmu_notifiers */
2547 old_page = vm_normal_page(vma, address, orig_pte);
2550 * VM_MIXEDMAP !pfn_valid() case
2552 * We should not cow pages in a shared writeable mapping.
2553 * Just mark the pages writable as we can't do any dirty
2554 * accounting on raw pfn maps.
2556 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2557 (VM_WRITE|VM_SHARED))
2563 * Take out anonymous pages first, anonymous shared vmas are
2564 * not dirty accountable.
2566 if (PageAnon(old_page) && !PageKsm(old_page)) {
2567 if (!trylock_page(old_page)) {
2568 page_cache_get(old_page);
2569 pte_unmap_unlock(page_table, ptl);
2570 lock_page(old_page);
2571 page_table = pte_offset_map_lock(mm, pmd, address,
2573 if (!pte_same(*page_table, orig_pte)) {
2574 unlock_page(old_page);
2577 page_cache_release(old_page);
2579 if (reuse_swap_page(old_page)) {
2581 * The page is all ours. Move it to our anon_vma so
2582 * the rmap code will not search our parent or siblings.
2583 * Protected against the rmap code by the page lock.
2585 page_move_anon_rmap(old_page, vma, address);
2586 unlock_page(old_page);
2589 unlock_page(old_page);
2590 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2591 (VM_WRITE|VM_SHARED))) {
2593 * Only catch write-faults on shared writable pages,
2594 * read-only shared pages can get COWed by
2595 * get_user_pages(.write=1, .force=1).
2597 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2598 struct vm_fault vmf;
2601 vmf.virtual_address = (void __user *)(address &
2603 vmf.pgoff = old_page->index;
2604 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2605 vmf.page = old_page;
2608 * Notify the address space that the page is about to
2609 * become writable so that it can prohibit this or wait
2610 * for the page to get into an appropriate state.
2612 * We do this without the lock held, so that it can
2613 * sleep if it needs to.
2615 page_cache_get(old_page);
2616 pte_unmap_unlock(page_table, ptl);
2618 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2620 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2622 goto unwritable_page;
2624 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2625 lock_page(old_page);
2626 if (!old_page->mapping) {
2627 ret = 0; /* retry the fault */
2628 unlock_page(old_page);
2629 goto unwritable_page;
2632 VM_BUG_ON(!PageLocked(old_page));
2635 * Since we dropped the lock we need to revalidate
2636 * the PTE as someone else may have changed it. If
2637 * they did, we just return, as we can count on the
2638 * MMU to tell us if they didn't also make it writable.
2640 page_table = pte_offset_map_lock(mm, pmd, address,
2642 if (!pte_same(*page_table, orig_pte)) {
2643 unlock_page(old_page);
2649 dirty_page = old_page;
2650 get_page(dirty_page);
2653 flush_cache_page(vma, address, pte_pfn(orig_pte));
2654 entry = pte_mkyoung(orig_pte);
2655 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2656 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2657 update_mmu_cache(vma, address, page_table);
2658 pte_unmap_unlock(page_table, ptl);
2659 ret |= VM_FAULT_WRITE;
2665 * Yes, Virginia, this is actually required to prevent a race
2666 * with clear_page_dirty_for_io() from clearing the page dirty
2667 * bit after it clear all dirty ptes, but before a racing
2668 * do_wp_page installs a dirty pte.
2670 * __do_fault is protected similarly.
2672 if (!page_mkwrite) {
2673 wait_on_page_locked(dirty_page);
2674 set_page_dirty_balance(dirty_page, page_mkwrite);
2675 /* file_update_time outside page_lock */
2677 file_update_time(vma->vm_file);
2679 put_page(dirty_page);
2681 struct address_space *mapping = dirty_page->mapping;
2683 set_page_dirty(dirty_page);
2684 unlock_page(dirty_page);
2685 page_cache_release(dirty_page);
2688 * Some device drivers do not set page.mapping
2689 * but still dirty their pages
2691 balance_dirty_pages_ratelimited(mapping);
2699 * Ok, we need to copy. Oh, well..
2701 page_cache_get(old_page);
2703 pte_unmap_unlock(page_table, ptl);
2705 if (unlikely(anon_vma_prepare(vma)))
2708 if (is_zero_pfn(pte_pfn(orig_pte))) {
2709 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2713 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2716 cow_user_page(new_page, old_page, address, vma);
2718 __SetPageUptodate(new_page);
2720 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2723 mmun_start = address & PAGE_MASK;
2724 mmun_end = mmun_start + PAGE_SIZE;
2725 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2728 * Re-check the pte - we dropped the lock
2730 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2731 if (likely(pte_same(*page_table, orig_pte))) {
2733 if (!PageAnon(old_page)) {
2734 dec_mm_counter_fast(mm, MM_FILEPAGES);
2735 inc_mm_counter_fast(mm, MM_ANONPAGES);
2738 inc_mm_counter_fast(mm, MM_ANONPAGES);
2739 flush_cache_page(vma, address, pte_pfn(orig_pte));
2740 entry = mk_pte(new_page, vma->vm_page_prot);
2741 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2743 * Clear the pte entry and flush it first, before updating the
2744 * pte with the new entry. This will avoid a race condition
2745 * seen in the presence of one thread doing SMC and another
2748 ptep_clear_flush(vma, address, page_table);
2749 page_add_new_anon_rmap(new_page, vma, address);
2751 * We call the notify macro here because, when using secondary
2752 * mmu page tables (such as kvm shadow page tables), we want the
2753 * new page to be mapped directly into the secondary page table.
2755 set_pte_at_notify(mm, address, page_table, entry);
2756 update_mmu_cache(vma, address, page_table);
2759 * Only after switching the pte to the new page may
2760 * we remove the mapcount here. Otherwise another
2761 * process may come and find the rmap count decremented
2762 * before the pte is switched to the new page, and
2763 * "reuse" the old page writing into it while our pte
2764 * here still points into it and can be read by other
2767 * The critical issue is to order this
2768 * page_remove_rmap with the ptp_clear_flush above.
2769 * Those stores are ordered by (if nothing else,)
2770 * the barrier present in the atomic_add_negative
2771 * in page_remove_rmap.
2773 * Then the TLB flush in ptep_clear_flush ensures that
2774 * no process can access the old page before the
2775 * decremented mapcount is visible. And the old page
2776 * cannot be reused until after the decremented
2777 * mapcount is visible. So transitively, TLBs to
2778 * old page will be flushed before it can be reused.
2780 page_remove_rmap(old_page);
2783 /* Free the old page.. */
2784 new_page = old_page;
2785 ret |= VM_FAULT_WRITE;
2787 mem_cgroup_uncharge_page(new_page);
2790 page_cache_release(new_page);
2792 pte_unmap_unlock(page_table, ptl);
2793 if (mmun_end > mmun_start)
2794 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2797 * Don't let another task, with possibly unlocked vma,
2798 * keep the mlocked page.
2800 if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) {
2801 lock_page(old_page); /* LRU manipulation */
2802 munlock_vma_page(old_page);
2803 unlock_page(old_page);
2805 page_cache_release(old_page);
2809 page_cache_release(new_page);
2812 page_cache_release(old_page);
2813 return VM_FAULT_OOM;
2816 page_cache_release(old_page);
2820 static void unmap_mapping_range_vma(struct vm_area_struct *vma,
2821 unsigned long start_addr, unsigned long end_addr,
2822 struct zap_details *details)
2824 zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
2827 static inline void unmap_mapping_range_tree(struct rb_root *root,
2828 struct zap_details *details)
2830 struct vm_area_struct *vma;
2831 pgoff_t vba, vea, zba, zea;
2833 vma_interval_tree_foreach(vma, root,
2834 details->first_index, details->last_index) {
2836 vba = vma->vm_pgoff;
2837 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2838 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2839 zba = details->first_index;
2842 zea = details->last_index;
2846 unmap_mapping_range_vma(vma,
2847 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2848 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2853 static inline void unmap_mapping_range_list(struct list_head *head,
2854 struct zap_details *details)
2856 struct vm_area_struct *vma;
2859 * In nonlinear VMAs there is no correspondence between virtual address
2860 * offset and file offset. So we must perform an exhaustive search
2861 * across *all* the pages in each nonlinear VMA, not just the pages
2862 * whose virtual address lies outside the file truncation point.
2864 list_for_each_entry(vma, head, shared.nonlinear) {
2865 details->nonlinear_vma = vma;
2866 unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
2871 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2872 * @mapping: the address space containing mmaps to be unmapped.
2873 * @holebegin: byte in first page to unmap, relative to the start of
2874 * the underlying file. This will be rounded down to a PAGE_SIZE
2875 * boundary. Note that this is different from truncate_pagecache(), which
2876 * must keep the partial page. In contrast, we must get rid of
2878 * @holelen: size of prospective hole in bytes. This will be rounded
2879 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2881 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2882 * but 0 when invalidating pagecache, don't throw away private data.
2884 void unmap_mapping_range(struct address_space *mapping,
2885 loff_t const holebegin, loff_t const holelen, int even_cows)
2887 struct zap_details details;
2888 pgoff_t hba = holebegin >> PAGE_SHIFT;
2889 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2891 /* Check for overflow. */
2892 if (sizeof(holelen) > sizeof(hlen)) {
2894 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2895 if (holeend & ~(long long)ULONG_MAX)
2896 hlen = ULONG_MAX - hba + 1;
2899 details.check_mapping = even_cows? NULL: mapping;
2900 details.nonlinear_vma = NULL;
2901 details.first_index = hba;
2902 details.last_index = hba + hlen - 1;
2903 if (details.last_index < details.first_index)
2904 details.last_index = ULONG_MAX;
2907 mutex_lock(&mapping->i_mmap_mutex);
2908 if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
2909 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2910 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2911 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2912 mutex_unlock(&mapping->i_mmap_mutex);
2914 EXPORT_SYMBOL(unmap_mapping_range);
2917 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2918 * but allow concurrent faults), and pte mapped but not yet locked.
2919 * We return with mmap_sem still held, but pte unmapped and unlocked.
2921 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2922 unsigned long address, pte_t *page_table, pmd_t *pmd,
2923 unsigned int flags, pte_t orig_pte)
2926 struct page *page, *swapcache = NULL;
2930 struct mem_cgroup *ptr;
2934 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2937 entry = pte_to_swp_entry(orig_pte);
2938 if (unlikely(non_swap_entry(entry))) {
2939 if (is_migration_entry(entry)) {
2940 migration_entry_wait(mm, pmd, address);
2941 } else if (is_hwpoison_entry(entry)) {
2942 ret = VM_FAULT_HWPOISON;
2944 print_bad_pte(vma, address, orig_pte, NULL);
2945 ret = VM_FAULT_SIGBUS;
2949 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2950 page = lookup_swap_cache(entry);
2952 page = swapin_readahead(entry,
2953 GFP_HIGHUSER_MOVABLE, vma, address);
2956 * Back out if somebody else faulted in this pte
2957 * while we released the pte lock.
2959 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2960 if (likely(pte_same(*page_table, orig_pte)))
2962 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2966 /* Had to read the page from swap area: Major fault */
2967 ret = VM_FAULT_MAJOR;
2968 count_vm_event(PGMAJFAULT);
2969 mem_cgroup_count_vm_event(mm, PGMAJFAULT);
2970 } else if (PageHWPoison(page)) {
2972 * hwpoisoned dirty swapcache pages are kept for killing
2973 * owner processes (which may be unknown at hwpoison time)
2975 ret = VM_FAULT_HWPOISON;
2976 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2980 locked = lock_page_or_retry(page, mm, flags);
2982 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2984 ret |= VM_FAULT_RETRY;
2989 * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
2990 * release the swapcache from under us. The page pin, and pte_same
2991 * test below, are not enough to exclude that. Even if it is still
2992 * swapcache, we need to check that the page's swap has not changed.
2994 if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
2997 if (ksm_might_need_to_copy(page, vma, address)) {
2999 page = ksm_does_need_to_copy(page, vma, address);
3001 if (unlikely(!page)) {
3009 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
3015 * Back out if somebody else already faulted in this pte.
3017 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3018 if (unlikely(!pte_same(*page_table, orig_pte)))
3021 if (unlikely(!PageUptodate(page))) {
3022 ret = VM_FAULT_SIGBUS;
3027 * The page isn't present yet, go ahead with the fault.
3029 * Be careful about the sequence of operations here.
3030 * To get its accounting right, reuse_swap_page() must be called
3031 * while the page is counted on swap but not yet in mapcount i.e.
3032 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
3033 * must be called after the swap_free(), or it will never succeed.
3034 * Because delete_from_swap_page() may be called by reuse_swap_page(),
3035 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
3036 * in page->private. In this case, a record in swap_cgroup is silently
3037 * discarded at swap_free().
3040 inc_mm_counter_fast(mm, MM_ANONPAGES);
3041 dec_mm_counter_fast(mm, MM_SWAPENTS);
3042 pte = mk_pte(page, vma->vm_page_prot);
3043 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
3044 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
3045 flags &= ~FAULT_FLAG_WRITE;
3046 ret |= VM_FAULT_WRITE;
3049 flush_icache_page(vma, page);
3050 set_pte_at(mm, address, page_table, pte);
3051 if (swapcache) /* ksm created a completely new copy */
3052 page_add_new_anon_rmap(page, vma, address);
3054 do_page_add_anon_rmap(page, vma, address, exclusive);
3055 /* It's better to call commit-charge after rmap is established */
3056 mem_cgroup_commit_charge_swapin(page, ptr);
3059 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
3060 try_to_free_swap(page);
3064 * Hold the lock to avoid the swap entry to be reused
3065 * until we take the PT lock for the pte_same() check
3066 * (to avoid false positives from pte_same). For
3067 * further safety release the lock after the swap_free
3068 * so that the swap count won't change under a
3069 * parallel locked swapcache.
3071 unlock_page(swapcache);
3072 page_cache_release(swapcache);
3075 if (flags & FAULT_FLAG_WRITE) {
3076 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
3077 if (ret & VM_FAULT_ERROR)
3078 ret &= VM_FAULT_ERROR;
3082 /* No need to invalidate - it was non-present before */
3083 update_mmu_cache(vma, address, page_table);
3085 pte_unmap_unlock(page_table, ptl);
3089 mem_cgroup_cancel_charge_swapin(ptr);
3090 pte_unmap_unlock(page_table, ptl);
3094 page_cache_release(page);
3096 unlock_page(swapcache);
3097 page_cache_release(swapcache);
3103 * This is like a special single-page "expand_{down|up}wards()",
3104 * except we must first make sure that 'address{-|+}PAGE_SIZE'
3105 * doesn't hit another vma.
3107 static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
3109 address &= PAGE_MASK;
3110 if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
3111 struct vm_area_struct *prev = vma->vm_prev;
3114 * Is there a mapping abutting this one below?
3116 * That's only ok if it's the same stack mapping
3117 * that has gotten split..
3119 if (prev && prev->vm_end == address)
3120 return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
3122 expand_downwards(vma, address - PAGE_SIZE);
3124 if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
3125 struct vm_area_struct *next = vma->vm_next;
3127 /* As VM_GROWSDOWN but s/below/above/ */
3128 if (next && next->vm_start == address + PAGE_SIZE)
3129 return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
3131 expand_upwards(vma, address + PAGE_SIZE);
3137 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3138 * but allow concurrent faults), and pte mapped but not yet locked.
3139 * We return with mmap_sem still held, but pte unmapped and unlocked.
3141 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
3142 unsigned long address, pte_t *page_table, pmd_t *pmd,
3149 pte_unmap(page_table);
3151 /* Check if we need to add a guard page to the stack */
3152 if (check_stack_guard_page(vma, address) < 0)
3153 return VM_FAULT_SIGBUS;
3155 /* Use the zero-page for reads */
3156 if (!(flags & FAULT_FLAG_WRITE)) {
3157 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
3158 vma->vm_page_prot));
3159 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3160 if (!pte_none(*page_table))
3165 /* Allocate our own private page. */
3166 if (unlikely(anon_vma_prepare(vma)))
3168 page = alloc_zeroed_user_highpage_movable(vma, address);
3171 __SetPageUptodate(page);
3173 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
3176 entry = mk_pte(page, vma->vm_page_prot);
3177 if (vma->vm_flags & VM_WRITE)
3178 entry = pte_mkwrite(pte_mkdirty(entry));
3180 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3181 if (!pte_none(*page_table))
3184 inc_mm_counter_fast(mm, MM_ANONPAGES);
3185 page_add_new_anon_rmap(page, vma, address);
3187 set_pte_at(mm, address, page_table, entry);
3189 /* No need to invalidate - it was non-present before */
3190 update_mmu_cache(vma, address, page_table);
3192 pte_unmap_unlock(page_table, ptl);
3195 mem_cgroup_uncharge_page(page);
3196 page_cache_release(page);
3199 page_cache_release(page);
3201 return VM_FAULT_OOM;
3205 * __do_fault() tries to create a new page mapping. It aggressively
3206 * tries to share with existing pages, but makes a separate copy if
3207 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
3208 * the next page fault.
3210 * As this is called only for pages that do not currently exist, we
3211 * do not need to flush old virtual caches or the TLB.
3213 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3214 * but allow concurrent faults), and pte neither mapped nor locked.
3215 * We return with mmap_sem still held, but pte unmapped and unlocked.
3217 static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3218 unsigned long address, pmd_t *pmd,
3219 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
3224 struct page *cow_page;
3227 struct page *dirty_page = NULL;
3228 struct vm_fault vmf;
3230 int page_mkwrite = 0;
3233 * If we do COW later, allocate page befor taking lock_page()
3234 * on the file cache page. This will reduce lock holding time.
3236 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3238 if (unlikely(anon_vma_prepare(vma)))
3239 return VM_FAULT_OOM;
3241 cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
3243 return VM_FAULT_OOM;
3245 if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) {
3246 page_cache_release(cow_page);
3247 return VM_FAULT_OOM;
3252 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
3257 ret = vma->vm_ops->fault(vma, &vmf);
3258 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
3262 if (unlikely(PageHWPoison(vmf.page))) {
3263 if (ret & VM_FAULT_LOCKED)
3264 unlock_page(vmf.page);
3265 ret = VM_FAULT_HWPOISON;
3270 * For consistency in subsequent calls, make the faulted page always
3273 if (unlikely(!(ret & VM_FAULT_LOCKED)))
3274 lock_page(vmf.page);
3276 VM_BUG_ON(!PageLocked(vmf.page));
3279 * Should we do an early C-O-W break?
3282 if (flags & FAULT_FLAG_WRITE) {
3283 if (!(vma->vm_flags & VM_SHARED)) {
3286 copy_user_highpage(page, vmf.page, address, vma);
3287 __SetPageUptodate(page);
3290 * If the page will be shareable, see if the backing
3291 * address space wants to know that the page is about
3292 * to become writable
3294 if (vma->vm_ops->page_mkwrite) {
3298 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
3299 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
3301 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
3303 goto unwritable_page;
3305 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
3307 if (!page->mapping) {
3308 ret = 0; /* retry the fault */
3310 goto unwritable_page;
3313 VM_BUG_ON(!PageLocked(page));
3320 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3323 * This silly early PAGE_DIRTY setting removes a race
3324 * due to the bad i386 page protection. But it's valid
3325 * for other architectures too.
3327 * Note that if FAULT_FLAG_WRITE is set, we either now have
3328 * an exclusive copy of the page, or this is a shared mapping,
3329 * so we can make it writable and dirty to avoid having to
3330 * handle that later.
3332 /* Only go through if we didn't race with anybody else... */
3333 if (likely(pte_same(*page_table, orig_pte))) {
3334 flush_icache_page(vma, page);
3335 entry = mk_pte(page, vma->vm_page_prot);
3336 if (flags & FAULT_FLAG_WRITE)
3337 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
3339 inc_mm_counter_fast(mm, MM_ANONPAGES);
3340 page_add_new_anon_rmap(page, vma, address);
3342 inc_mm_counter_fast(mm, MM_FILEPAGES);
3343 page_add_file_rmap(page);
3344 if (flags & FAULT_FLAG_WRITE) {
3346 get_page(dirty_page);
3349 set_pte_at(mm, address, page_table, entry);
3351 /* no need to invalidate: a not-present page won't be cached */
3352 update_mmu_cache(vma, address, page_table);
3355 mem_cgroup_uncharge_page(cow_page);
3357 page_cache_release(page);
3359 anon = 1; /* no anon but release faulted_page */
3362 pte_unmap_unlock(page_table, ptl);
3365 struct address_space *mapping = page->mapping;
3368 if (set_page_dirty(dirty_page))
3370 unlock_page(dirty_page);
3371 put_page(dirty_page);
3372 if ((dirtied || page_mkwrite) && mapping) {
3374 * Some device drivers do not set page.mapping but still
3377 balance_dirty_pages_ratelimited(mapping);
3380 /* file_update_time outside page_lock */
3381 if (vma->vm_file && !page_mkwrite)
3382 file_update_time(vma->vm_file);
3384 unlock_page(vmf.page);
3386 page_cache_release(vmf.page);
3392 page_cache_release(page);
3395 /* fs's fault handler get error */
3397 mem_cgroup_uncharge_page(cow_page);
3398 page_cache_release(cow_page);
3403 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3404 unsigned long address, pte_t *page_table, pmd_t *pmd,
3405 unsigned int flags, pte_t orig_pte)
3407 pgoff_t pgoff = (((address & PAGE_MASK)
3408 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3410 pte_unmap(page_table);
3411 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3415 * Fault of a previously existing named mapping. Repopulate the pte
3416 * from the encoded file_pte if possible. This enables swappable
3419 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3420 * but allow concurrent faults), and pte mapped but not yet locked.
3421 * We return with mmap_sem still held, but pte unmapped and unlocked.
3423 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3424 unsigned long address, pte_t *page_table, pmd_t *pmd,
3425 unsigned int flags, pte_t orig_pte)
3429 flags |= FAULT_FLAG_NONLINEAR;
3431 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3434 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3436 * Page table corrupted: show pte and kill process.
3438 print_bad_pte(vma, address, orig_pte, NULL);
3439 return VM_FAULT_SIGBUS;
3442 pgoff = pte_to_pgoff(orig_pte);
3443 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3446 int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
3447 unsigned long addr, int current_nid)
3451 count_vm_numa_event(NUMA_HINT_FAULTS);
3452 if (current_nid == numa_node_id())
3453 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
3455 return mpol_misplaced(page, vma, addr);
3458 int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3459 unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
3461 struct page *page = NULL;
3463 int current_nid = -1;
3465 bool migrated = false;
3468 * The "pte" at this point cannot be used safely without
3469 * validation through pte_unmap_same(). It's of NUMA type but
3470 * the pfn may be screwed if the read is non atomic.
3472 * ptep_modify_prot_start is not called as this is clearing
3473 * the _PAGE_NUMA bit and it is not really expected that there
3474 * would be concurrent hardware modifications to the PTE.
3476 ptl = pte_lockptr(mm, pmd);
3478 if (unlikely(!pte_same(*ptep, pte))) {
3479 pte_unmap_unlock(ptep, ptl);
3483 pte = pte_mknonnuma(pte);
3484 set_pte_at(mm, addr, ptep, pte);
3485 update_mmu_cache(vma, addr, ptep);
3487 page = vm_normal_page(vma, addr, pte);
3489 pte_unmap_unlock(ptep, ptl);
3493 current_nid = page_to_nid(page);
3494 target_nid = numa_migrate_prep(page, vma, addr, current_nid);
3495 pte_unmap_unlock(ptep, ptl);
3496 if (target_nid == -1) {
3498 * Account for the fault against the current node if it not
3499 * being replaced regardless of where the page is located.
3501 current_nid = numa_node_id();
3506 /* Migrate to the requested node */
3507 migrated = migrate_misplaced_page(page, target_nid);
3509 current_nid = target_nid;
3512 if (current_nid != -1)
3513 task_numa_fault(current_nid, 1, migrated);
3517 /* NUMA hinting page fault entry point for regular pmds */
3518 #ifdef CONFIG_NUMA_BALANCING
3519 static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3520 unsigned long addr, pmd_t *pmdp)
3523 pte_t *pte, *orig_pte;
3524 unsigned long _addr = addr & PMD_MASK;
3525 unsigned long offset;
3528 int local_nid = numa_node_id();
3530 spin_lock(&mm->page_table_lock);
3532 if (pmd_numa(pmd)) {
3533 set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd));
3536 spin_unlock(&mm->page_table_lock);
3541 /* we're in a page fault so some vma must be in the range */
3543 BUG_ON(vma->vm_start >= _addr + PMD_SIZE);
3544 offset = max(_addr, vma->vm_start) & ~PMD_MASK;
3545 VM_BUG_ON(offset >= PMD_SIZE);
3546 orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl);
3547 pte += offset >> PAGE_SHIFT;
3548 for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) {
3549 pte_t pteval = *pte;
3551 int curr_nid = local_nid;
3554 if (!pte_present(pteval))
3556 if (!pte_numa(pteval))
3558 if (addr >= vma->vm_end) {
3559 vma = find_vma(mm, addr);
3560 /* there's a pte present so there must be a vma */
3562 BUG_ON(addr < vma->vm_start);
3564 if (pte_numa(pteval)) {
3565 pteval = pte_mknonnuma(pteval);
3566 set_pte_at(mm, addr, pte, pteval);
3568 page = vm_normal_page(vma, addr, pteval);
3569 if (unlikely(!page))
3571 /* only check non-shared pages */
3572 if (unlikely(page_mapcount(page) != 1))
3576 * Note that the NUMA fault is later accounted to either
3577 * the node that is currently running or where the page is
3580 curr_nid = local_nid;
3581 target_nid = numa_migrate_prep(page, vma, addr,
3583 if (target_nid == -1) {
3588 /* Migrate to the requested node */
3589 pte_unmap_unlock(pte, ptl);
3590 migrated = migrate_misplaced_page(page, target_nid);
3592 curr_nid = target_nid;
3593 task_numa_fault(curr_nid, 1, migrated);
3595 pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
3597 pte_unmap_unlock(orig_pte, ptl);
3602 static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3603 unsigned long addr, pmd_t *pmdp)
3608 #endif /* CONFIG_NUMA_BALANCING */
3611 * These routines also need to handle stuff like marking pages dirty
3612 * and/or accessed for architectures that don't do it in hardware (most
3613 * RISC architectures). The early dirtying is also good on the i386.
3615 * There is also a hook called "update_mmu_cache()" that architectures
3616 * with external mmu caches can use to update those (ie the Sparc or
3617 * PowerPC hashed page tables that act as extended TLBs).
3619 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3620 * but allow concurrent faults), and pte mapped but not yet locked.
3621 * We return with mmap_sem still held, but pte unmapped and unlocked.
3623 int handle_pte_fault(struct mm_struct *mm,
3624 struct vm_area_struct *vma, unsigned long address,
3625 pte_t *pte, pmd_t *pmd, unsigned int flags)
3631 if (!pte_present(entry)) {
3632 if (pte_none(entry)) {
3634 if (likely(vma->vm_ops->fault))
3635 return do_linear_fault(mm, vma, address,
3636 pte, pmd, flags, entry);
3638 return do_anonymous_page(mm, vma, address,
3641 if (pte_file(entry))
3642 return do_nonlinear_fault(mm, vma, address,
3643 pte, pmd, flags, entry);
3644 return do_swap_page(mm, vma, address,
3645 pte, pmd, flags, entry);
3648 if (pte_numa(entry))
3649 return do_numa_page(mm, vma, address, entry, pte, pmd);
3651 ptl = pte_lockptr(mm, pmd);
3653 if (unlikely(!pte_same(*pte, entry)))
3655 if (flags & FAULT_FLAG_WRITE) {
3656 if (!pte_write(entry))
3657 return do_wp_page(mm, vma, address,
3658 pte, pmd, ptl, entry);
3659 entry = pte_mkdirty(entry);
3661 entry = pte_mkyoung(entry);
3662 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3663 update_mmu_cache(vma, address, pte);
3666 * This is needed only for protection faults but the arch code
3667 * is not yet telling us if this is a protection fault or not.
3668 * This still avoids useless tlb flushes for .text page faults
3671 if (flags & FAULT_FLAG_WRITE)
3672 flush_tlb_fix_spurious_fault(vma, address);
3675 pte_unmap_unlock(pte, ptl);
3680 * By the time we get here, we already hold the mm semaphore
3682 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3683 unsigned long address, unsigned int flags)
3690 __set_current_state(TASK_RUNNING);
3692 count_vm_event(PGFAULT);
3693 mem_cgroup_count_vm_event(mm, PGFAULT);
3695 /* do counter updates before entering really critical section. */
3696 check_sync_rss_stat(current);
3698 if (unlikely(is_vm_hugetlb_page(vma)))
3699 return hugetlb_fault(mm, vma, address, flags);
3702 pgd = pgd_offset(mm, address);
3703 pud = pud_alloc(mm, pgd, address);
3705 return VM_FAULT_OOM;
3706 pmd = pmd_alloc(mm, pud, address);
3708 return VM_FAULT_OOM;
3709 if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
3711 return do_huge_pmd_anonymous_page(mm, vma, address,
3714 pmd_t orig_pmd = *pmd;
3718 if (pmd_trans_huge(orig_pmd)) {
3719 unsigned int dirty = flags & FAULT_FLAG_WRITE;
3722 * If the pmd is splitting, return and retry the
3723 * the fault. Alternative: wait until the split
3724 * is done, and goto retry.
3726 if (pmd_trans_splitting(orig_pmd))
3729 if (pmd_numa(orig_pmd))
3730 return do_huge_pmd_numa_page(mm, vma, address,
3733 if (dirty && !pmd_write(orig_pmd)) {
3734 ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
3737 * If COW results in an oom, the huge pmd will
3738 * have been split, so retry the fault on the
3739 * pte for a smaller charge.
3741 if (unlikely(ret & VM_FAULT_OOM))
3745 huge_pmd_set_accessed(mm, vma, address, pmd,
3754 return do_pmd_numa_page(mm, vma, address, pmd);
3757 * Use __pte_alloc instead of pte_alloc_map, because we can't
3758 * run pte_offset_map on the pmd, if an huge pmd could
3759 * materialize from under us from a different thread.
3761 if (unlikely(pmd_none(*pmd)) &&
3762 unlikely(__pte_alloc(mm, vma, pmd, address)))
3763 return VM_FAULT_OOM;
3764 /* if an huge pmd materialized from under us just retry later */
3765 if (unlikely(pmd_trans_huge(*pmd)))
3768 * A regular pmd is established and it can't morph into a huge pmd
3769 * from under us anymore at this point because we hold the mmap_sem
3770 * read mode and khugepaged takes it in write mode. So now it's
3771 * safe to run pte_offset_map().
3773 pte = pte_offset_map(pmd, address);
3775 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3778 #ifndef __PAGETABLE_PUD_FOLDED
3780 * Allocate page upper directory.
3781 * We've already handled the fast-path in-line.
3783 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3785 pud_t *new = pud_alloc_one(mm, address);
3789 smp_wmb(); /* See comment in __pte_alloc */
3791 spin_lock(&mm->page_table_lock);
3792 if (pgd_present(*pgd)) /* Another has populated it */
3795 pgd_populate(mm, pgd, new);
3796 spin_unlock(&mm->page_table_lock);
3799 #endif /* __PAGETABLE_PUD_FOLDED */
3801 #ifndef __PAGETABLE_PMD_FOLDED
3803 * Allocate page middle directory.
3804 * We've already handled the fast-path in-line.
3806 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3808 pmd_t *new = pmd_alloc_one(mm, address);
3812 smp_wmb(); /* See comment in __pte_alloc */
3814 spin_lock(&mm->page_table_lock);
3815 #ifndef __ARCH_HAS_4LEVEL_HACK
3816 if (pud_present(*pud)) /* Another has populated it */
3819 pud_populate(mm, pud, new);
3821 if (pgd_present(*pud)) /* Another has populated it */
3824 pgd_populate(mm, pud, new);
3825 #endif /* __ARCH_HAS_4LEVEL_HACK */
3826 spin_unlock(&mm->page_table_lock);
3829 #endif /* __PAGETABLE_PMD_FOLDED */
3831 #if !defined(__HAVE_ARCH_GATE_AREA)
3833 #if defined(AT_SYSINFO_EHDR)
3834 static struct vm_area_struct gate_vma;
3836 static int __init gate_vma_init(void)
3838 gate_vma.vm_mm = NULL;
3839 gate_vma.vm_start = FIXADDR_USER_START;
3840 gate_vma.vm_end = FIXADDR_USER_END;
3841 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3842 gate_vma.vm_page_prot = __P101;
3846 __initcall(gate_vma_init);
3849 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
3851 #ifdef AT_SYSINFO_EHDR
3858 int in_gate_area_no_mm(unsigned long addr)
3860 #ifdef AT_SYSINFO_EHDR
3861 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3867 #endif /* __HAVE_ARCH_GATE_AREA */
3869 static int __follow_pte(struct mm_struct *mm, unsigned long address,
3870 pte_t **ptepp, spinlock_t **ptlp)
3877 pgd = pgd_offset(mm, address);
3878 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3881 pud = pud_offset(pgd, address);
3882 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3885 pmd = pmd_offset(pud, address);
3886 VM_BUG_ON(pmd_trans_huge(*pmd));
3887 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3890 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3894 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3897 if (!pte_present(*ptep))
3902 pte_unmap_unlock(ptep, *ptlp);
3907 static inline int follow_pte(struct mm_struct *mm, unsigned long address,
3908 pte_t **ptepp, spinlock_t **ptlp)
3912 /* (void) is needed to make gcc happy */
3913 (void) __cond_lock(*ptlp,
3914 !(res = __follow_pte(mm, address, ptepp, ptlp)));
3919 * follow_pfn - look up PFN at a user virtual address
3920 * @vma: memory mapping
3921 * @address: user virtual address
3922 * @pfn: location to store found PFN
3924 * Only IO mappings and raw PFN mappings are allowed.
3926 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3928 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3935 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3938 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3941 *pfn = pte_pfn(*ptep);
3942 pte_unmap_unlock(ptep, ptl);
3945 EXPORT_SYMBOL(follow_pfn);
3947 #ifdef CONFIG_HAVE_IOREMAP_PROT
3948 int follow_phys(struct vm_area_struct *vma,
3949 unsigned long address, unsigned int flags,
3950 unsigned long *prot, resource_size_t *phys)
3956 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3959 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
3963 if ((flags & FOLL_WRITE) && !pte_write(pte))
3966 *prot = pgprot_val(pte_pgprot(pte));
3967 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
3971 pte_unmap_unlock(ptep, ptl);
3976 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3977 void *buf, int len, int write)
3979 resource_size_t phys_addr;
3980 unsigned long prot = 0;
3981 void __iomem *maddr;
3982 int offset = addr & (PAGE_SIZE-1);
3984 if (follow_phys(vma, addr, write, &prot, &phys_addr))
3987 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3989 memcpy_toio(maddr + offset, buf, len);
3991 memcpy_fromio(buf, maddr + offset, len);
3999 * Access another process' address space as given in mm. If non-NULL, use the
4000 * given task for page fault accounting.
4002 static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
4003 unsigned long addr, void *buf, int len, int write)
4005 struct vm_area_struct *vma;
4006 void *old_buf = buf;
4008 down_read(&mm->mmap_sem);
4009 /* ignore errors, just check how much was successfully transferred */
4011 int bytes, ret, offset;
4013 struct page *page = NULL;
4015 ret = get_user_pages(tsk, mm, addr, 1,
4016 write, 1, &page, &vma);
4019 * Check if this is a VM_IO | VM_PFNMAP VMA, which
4020 * we can access using slightly different code.
4022 #ifdef CONFIG_HAVE_IOREMAP_PROT
4023 vma = find_vma(mm, addr);
4024 if (!vma || vma->vm_start > addr)
4026 if (vma->vm_ops && vma->vm_ops->access)
4027 ret = vma->vm_ops->access(vma, addr, buf,
4035 offset = addr & (PAGE_SIZE-1);
4036 if (bytes > PAGE_SIZE-offset)
4037 bytes = PAGE_SIZE-offset;
4041 copy_to_user_page(vma, page, addr,
4042 maddr + offset, buf, bytes);
4043 set_page_dirty_lock(page);
4045 copy_from_user_page(vma, page, addr,
4046 buf, maddr + offset, bytes);
4049 page_cache_release(page);
4055 up_read(&mm->mmap_sem);
4057 return buf - old_buf;
4061 * access_remote_vm - access another process' address space
4062 * @mm: the mm_struct of the target address space
4063 * @addr: start address to access
4064 * @buf: source or destination buffer
4065 * @len: number of bytes to transfer
4066 * @write: whether the access is a write
4068 * The caller must hold a reference on @mm.
4070 int access_remote_vm(struct mm_struct *mm, unsigned long addr,
4071 void *buf, int len, int write)
4073 return __access_remote_vm(NULL, mm, addr, buf, len, write);
4077 * Access another process' address space.
4078 * Source/target buffer must be kernel space,
4079 * Do not walk the page table directly, use get_user_pages
4081 int access_process_vm(struct task_struct *tsk, unsigned long addr,
4082 void *buf, int len, int write)
4084 struct mm_struct *mm;
4087 mm = get_task_mm(tsk);
4091 ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
4098 * Print the name of a VMA.
4100 void print_vma_addr(char *prefix, unsigned long ip)
4102 struct mm_struct *mm = current->mm;
4103 struct vm_area_struct *vma;
4106 * Do not print if we are in atomic
4107 * contexts (in exception stacks, etc.):
4109 if (preempt_count())
4112 down_read(&mm->mmap_sem);
4113 vma = find_vma(mm, ip);
4114 if (vma && vma->vm_file) {
4115 struct file *f = vma->vm_file;
4116 char *buf = (char *)__get_free_page(GFP_KERNEL);
4120 p = d_path(&f->f_path, buf, PAGE_SIZE);
4123 printk("%s%s[%lx+%lx]", prefix, kbasename(p),
4125 vma->vm_end - vma->vm_start);
4126 free_page((unsigned long)buf);
4129 up_read(&mm->mmap_sem);
4132 #ifdef CONFIG_PROVE_LOCKING
4133 void might_fault(void)
4136 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4137 * holding the mmap_sem, this is safe because kernel memory doesn't
4138 * get paged out, therefore we'll never actually fault, and the
4139 * below annotations will generate false positives.
4141 if (segment_eq(get_fs(), KERNEL_DS))
4146 * it would be nicer only to annotate paths which are not under
4147 * pagefault_disable, however that requires a larger audit and
4148 * providing helpers like get_user_atomic.
4150 if (!in_atomic() && current->mm)
4151 might_lock_read(¤t->mm->mmap_sem);
4153 EXPORT_SYMBOL(might_fault);
4156 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4157 static void clear_gigantic_page(struct page *page,
4159 unsigned int pages_per_huge_page)
4162 struct page *p = page;
4165 for (i = 0; i < pages_per_huge_page;
4166 i++, p = mem_map_next(p, page, i)) {
4168 clear_user_highpage(p, addr + i * PAGE_SIZE);
4171 void clear_huge_page(struct page *page,
4172 unsigned long addr, unsigned int pages_per_huge_page)
4176 if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4177 clear_gigantic_page(page, addr, pages_per_huge_page);
4182 for (i = 0; i < pages_per_huge_page; i++) {
4184 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
4188 static void copy_user_gigantic_page(struct page *dst, struct page *src,
4190 struct vm_area_struct *vma,
4191 unsigned int pages_per_huge_page)
4194 struct page *dst_base = dst;
4195 struct page *src_base = src;
4197 for (i = 0; i < pages_per_huge_page; ) {
4199 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
4202 dst = mem_map_next(dst, dst_base, i);
4203 src = mem_map_next(src, src_base, i);
4207 void copy_user_huge_page(struct page *dst, struct page *src,
4208 unsigned long addr, struct vm_area_struct *vma,
4209 unsigned int pages_per_huge_page)
4213 if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4214 copy_user_gigantic_page(dst, src, addr, vma,
4215 pages_per_huge_page);
4220 for (i = 0; i < pages_per_huge_page; i++) {
4222 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
4225 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */