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_mask - 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
1469 * @page_mask: on output, *page_mask is set according to the size of the page
1471 * @flags can have FOLL_ flags set, defined in <linux/mm.h>
1473 * Returns the mapped (struct page *), %NULL if no mapping exists, or
1474 * an error pointer if there is a mapping to something not represented
1475 * by a page descriptor (see also vm_normal_page()).
1477 struct page *follow_page_mask(struct vm_area_struct *vma,
1478 unsigned long address, unsigned int flags,
1479 unsigned int *page_mask)
1487 struct mm_struct *mm = vma->vm_mm;
1491 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1492 if (!IS_ERR(page)) {
1493 BUG_ON(flags & FOLL_GET);
1498 pgd = pgd_offset(mm, address);
1499 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1502 pud = pud_offset(pgd, address);
1505 if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
1506 BUG_ON(flags & FOLL_GET);
1507 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1510 if (unlikely(pud_bad(*pud)))
1513 pmd = pmd_offset(pud, address);
1516 if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) {
1517 BUG_ON(flags & FOLL_GET);
1518 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1521 if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
1523 if (pmd_trans_huge(*pmd)) {
1524 if (flags & FOLL_SPLIT) {
1525 split_huge_page_pmd(vma, address, pmd);
1526 goto split_fallthrough;
1528 spin_lock(&mm->page_table_lock);
1529 if (likely(pmd_trans_huge(*pmd))) {
1530 if (unlikely(pmd_trans_splitting(*pmd))) {
1531 spin_unlock(&mm->page_table_lock);
1532 wait_split_huge_page(vma->anon_vma, pmd);
1534 page = follow_trans_huge_pmd(vma, address,
1536 spin_unlock(&mm->page_table_lock);
1537 *page_mask = HPAGE_PMD_NR - 1;
1541 spin_unlock(&mm->page_table_lock);
1545 if (unlikely(pmd_bad(*pmd)))
1548 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1551 if (!pte_present(pte))
1553 if ((flags & FOLL_NUMA) && pte_numa(pte))
1555 if ((flags & FOLL_WRITE) && !pte_write(pte))
1558 page = vm_normal_page(vma, address, pte);
1559 if (unlikely(!page)) {
1560 if ((flags & FOLL_DUMP) ||
1561 !is_zero_pfn(pte_pfn(pte)))
1563 page = pte_page(pte);
1566 if (flags & FOLL_GET)
1567 get_page_foll(page);
1568 if (flags & FOLL_TOUCH) {
1569 if ((flags & FOLL_WRITE) &&
1570 !pte_dirty(pte) && !PageDirty(page))
1571 set_page_dirty(page);
1573 * pte_mkyoung() would be more correct here, but atomic care
1574 * is needed to avoid losing the dirty bit: it is easier to use
1575 * mark_page_accessed().
1577 mark_page_accessed(page);
1579 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1581 * The preliminary mapping check is mainly to avoid the
1582 * pointless overhead of lock_page on the ZERO_PAGE
1583 * which might bounce very badly if there is contention.
1585 * If the page is already locked, we don't need to
1586 * handle it now - vmscan will handle it later if and
1587 * when it attempts to reclaim the page.
1589 if (page->mapping && trylock_page(page)) {
1590 lru_add_drain(); /* push cached pages to LRU */
1592 * Because we lock page here, and migration is
1593 * blocked by the pte's page reference, and we
1594 * know the page is still mapped, we don't even
1595 * need to check for file-cache page truncation.
1597 mlock_vma_page(page);
1602 pte_unmap_unlock(ptep, ptl);
1607 pte_unmap_unlock(ptep, ptl);
1608 return ERR_PTR(-EFAULT);
1611 pte_unmap_unlock(ptep, ptl);
1617 * When core dumping an enormous anonymous area that nobody
1618 * has touched so far, we don't want to allocate unnecessary pages or
1619 * page tables. Return error instead of NULL to skip handle_mm_fault,
1620 * then get_dump_page() will return NULL to leave a hole in the dump.
1621 * But we can only make this optimization where a hole would surely
1622 * be zero-filled if handle_mm_fault() actually did handle it.
1624 if ((flags & FOLL_DUMP) &&
1625 (!vma->vm_ops || !vma->vm_ops->fault))
1626 return ERR_PTR(-EFAULT);
1630 static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
1632 return stack_guard_page_start(vma, addr) ||
1633 stack_guard_page_end(vma, addr+PAGE_SIZE);
1637 * __get_user_pages() - pin user pages in memory
1638 * @tsk: task_struct of target task
1639 * @mm: mm_struct of target mm
1640 * @start: starting user address
1641 * @nr_pages: number of pages from start to pin
1642 * @gup_flags: flags modifying pin behaviour
1643 * @pages: array that receives pointers to the pages pinned.
1644 * Should be at least nr_pages long. Or NULL, if caller
1645 * only intends to ensure the pages are faulted in.
1646 * @vmas: array of pointers to vmas corresponding to each page.
1647 * Or NULL if the caller does not require them.
1648 * @nonblocking: whether waiting for disk IO or mmap_sem contention
1650 * Returns number of pages pinned. This may be fewer than the number
1651 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1652 * were pinned, returns -errno. Each page returned must be released
1653 * with a put_page() call when it is finished with. vmas will only
1654 * remain valid while mmap_sem is held.
1656 * Must be called with mmap_sem held for read or write.
1658 * __get_user_pages walks a process's page tables and takes a reference to
1659 * each struct page that each user address corresponds to at a given
1660 * instant. That is, it takes the page that would be accessed if a user
1661 * thread accesses the given user virtual address at that instant.
1663 * This does not guarantee that the page exists in the user mappings when
1664 * __get_user_pages returns, and there may even be a completely different
1665 * page there in some cases (eg. if mmapped pagecache has been invalidated
1666 * and subsequently re faulted). However it does guarantee that the page
1667 * won't be freed completely. And mostly callers simply care that the page
1668 * contains data that was valid *at some point in time*. Typically, an IO
1669 * or similar operation cannot guarantee anything stronger anyway because
1670 * locks can't be held over the syscall boundary.
1672 * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
1673 * the page is written to, set_page_dirty (or set_page_dirty_lock, as
1674 * appropriate) must be called after the page is finished with, and
1675 * before put_page is called.
1677 * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
1678 * or mmap_sem contention, and if waiting is needed to pin all pages,
1679 * *@nonblocking will be set to 0.
1681 * In most cases, get_user_pages or get_user_pages_fast should be used
1682 * instead of __get_user_pages. __get_user_pages should be used only if
1683 * you need some special @gup_flags.
1685 long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1686 unsigned long start, unsigned long nr_pages,
1687 unsigned int gup_flags, struct page **pages,
1688 struct vm_area_struct **vmas, int *nonblocking)
1691 unsigned long vm_flags;
1692 unsigned int page_mask;
1697 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1700 * Require read or write permissions.
1701 * If FOLL_FORCE is set, we only require the "MAY" flags.
1703 vm_flags = (gup_flags & FOLL_WRITE) ?
1704 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1705 vm_flags &= (gup_flags & FOLL_FORCE) ?
1706 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1709 * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
1710 * would be called on PROT_NONE ranges. We must never invoke
1711 * handle_mm_fault on PROT_NONE ranges or the NUMA hinting
1712 * page faults would unprotect the PROT_NONE ranges if
1713 * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd
1714 * bitflag. So to avoid that, don't set FOLL_NUMA if
1715 * FOLL_FORCE is set.
1717 if (!(gup_flags & FOLL_FORCE))
1718 gup_flags |= FOLL_NUMA;
1723 struct vm_area_struct *vma;
1725 vma = find_extend_vma(mm, start);
1726 if (!vma && in_gate_area(mm, start)) {
1727 unsigned long pg = start & PAGE_MASK;
1733 /* user gate pages are read-only */
1734 if (gup_flags & FOLL_WRITE)
1735 return i ? : -EFAULT;
1737 pgd = pgd_offset_k(pg);
1739 pgd = pgd_offset_gate(mm, pg);
1740 BUG_ON(pgd_none(*pgd));
1741 pud = pud_offset(pgd, pg);
1742 BUG_ON(pud_none(*pud));
1743 pmd = pmd_offset(pud, pg);
1745 return i ? : -EFAULT;
1746 VM_BUG_ON(pmd_trans_huge(*pmd));
1747 pte = pte_offset_map(pmd, pg);
1748 if (pte_none(*pte)) {
1750 return i ? : -EFAULT;
1752 vma = get_gate_vma(mm);
1756 page = vm_normal_page(vma, start, *pte);
1758 if (!(gup_flags & FOLL_DUMP) &&
1759 is_zero_pfn(pte_pfn(*pte)))
1760 page = pte_page(*pte);
1763 return i ? : -EFAULT;
1775 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1776 !(vm_flags & vma->vm_flags))
1777 return i ? : -EFAULT;
1779 if (is_vm_hugetlb_page(vma)) {
1780 i = follow_hugetlb_page(mm, vma, pages, vmas,
1781 &start, &nr_pages, i, gup_flags);
1787 unsigned int foll_flags = gup_flags;
1788 unsigned int page_increm;
1791 * If we have a pending SIGKILL, don't keep faulting
1792 * pages and potentially allocating memory.
1794 if (unlikely(fatal_signal_pending(current)))
1795 return i ? i : -ERESTARTSYS;
1798 while (!(page = follow_page_mask(vma, start,
1799 foll_flags, &page_mask))) {
1801 unsigned int fault_flags = 0;
1803 /* For mlock, just skip the stack guard page. */
1804 if (foll_flags & FOLL_MLOCK) {
1805 if (stack_guard_page(vma, start))
1808 if (foll_flags & FOLL_WRITE)
1809 fault_flags |= FAULT_FLAG_WRITE;
1811 fault_flags |= FAULT_FLAG_ALLOW_RETRY;
1812 if (foll_flags & FOLL_NOWAIT)
1813 fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT);
1815 ret = handle_mm_fault(mm, vma, start,
1818 if (ret & VM_FAULT_ERROR) {
1819 if (ret & VM_FAULT_OOM)
1820 return i ? i : -ENOMEM;
1821 if (ret & (VM_FAULT_HWPOISON |
1822 VM_FAULT_HWPOISON_LARGE)) {
1825 else if (gup_flags & FOLL_HWPOISON)
1830 if (ret & VM_FAULT_SIGBUS)
1831 return i ? i : -EFAULT;
1836 if (ret & VM_FAULT_MAJOR)
1842 if (ret & VM_FAULT_RETRY) {
1849 * The VM_FAULT_WRITE bit tells us that
1850 * do_wp_page has broken COW when necessary,
1851 * even if maybe_mkwrite decided not to set
1852 * pte_write. We can thus safely do subsequent
1853 * page lookups as if they were reads. But only
1854 * do so when looping for pte_write is futile:
1855 * in some cases userspace may also be wanting
1856 * to write to the gotten user page, which a
1857 * read fault here might prevent (a readonly
1858 * page might get reCOWed by userspace write).
1860 if ((ret & VM_FAULT_WRITE) &&
1861 !(vma->vm_flags & VM_WRITE))
1862 foll_flags &= ~FOLL_WRITE;
1867 return i ? i : PTR_ERR(page);
1871 flush_anon_page(vma, page, start);
1872 flush_dcache_page(page);
1880 page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
1881 if (page_increm > nr_pages)
1882 page_increm = nr_pages;
1884 start += page_increm * PAGE_SIZE;
1885 nr_pages -= page_increm;
1886 } while (nr_pages && start < vma->vm_end);
1890 EXPORT_SYMBOL(__get_user_pages);
1893 * fixup_user_fault() - manually resolve a user page fault
1894 * @tsk: the task_struct to use for page fault accounting, or
1895 * NULL if faults are not to be recorded.
1896 * @mm: mm_struct of target mm
1897 * @address: user address
1898 * @fault_flags:flags to pass down to handle_mm_fault()
1900 * This is meant to be called in the specific scenario where for locking reasons
1901 * we try to access user memory in atomic context (within a pagefault_disable()
1902 * section), this returns -EFAULT, and we want to resolve the user fault before
1905 * Typically this is meant to be used by the futex code.
1907 * The main difference with get_user_pages() is that this function will
1908 * unconditionally call handle_mm_fault() which will in turn perform all the
1909 * necessary SW fixup of the dirty and young bits in the PTE, while
1910 * handle_mm_fault() only guarantees to update these in the struct page.
1912 * This is important for some architectures where those bits also gate the
1913 * access permission to the page because they are maintained in software. On
1914 * such architectures, gup() will not be enough to make a subsequent access
1917 * This should be called with the mm_sem held for read.
1919 int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1920 unsigned long address, unsigned int fault_flags)
1922 struct vm_area_struct *vma;
1925 vma = find_extend_vma(mm, address);
1926 if (!vma || address < vma->vm_start)
1929 ret = handle_mm_fault(mm, vma, address, fault_flags);
1930 if (ret & VM_FAULT_ERROR) {
1931 if (ret & VM_FAULT_OOM)
1933 if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
1935 if (ret & VM_FAULT_SIGBUS)
1940 if (ret & VM_FAULT_MAJOR)
1949 * get_user_pages() - pin user pages in memory
1950 * @tsk: the task_struct to use for page fault accounting, or
1951 * NULL if faults are not to be recorded.
1952 * @mm: mm_struct of target mm
1953 * @start: starting user address
1954 * @nr_pages: number of pages from start to pin
1955 * @write: whether pages will be written to by the caller
1956 * @force: whether to force write access even if user mapping is
1957 * readonly. This will result in the page being COWed even
1958 * in MAP_SHARED mappings. You do not want this.
1959 * @pages: array that receives pointers to the pages pinned.
1960 * Should be at least nr_pages long. Or NULL, if caller
1961 * only intends to ensure the pages are faulted in.
1962 * @vmas: array of pointers to vmas corresponding to each page.
1963 * Or NULL if the caller does not require them.
1965 * Returns number of pages pinned. This may be fewer than the number
1966 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1967 * were pinned, returns -errno. Each page returned must be released
1968 * with a put_page() call when it is finished with. vmas will only
1969 * remain valid while mmap_sem is held.
1971 * Must be called with mmap_sem held for read or write.
1973 * get_user_pages walks a process's page tables and takes a reference to
1974 * each struct page that each user address corresponds to at a given
1975 * instant. That is, it takes the page that would be accessed if a user
1976 * thread accesses the given user virtual address at that instant.
1978 * This does not guarantee that the page exists in the user mappings when
1979 * get_user_pages returns, and there may even be a completely different
1980 * page there in some cases (eg. if mmapped pagecache has been invalidated
1981 * and subsequently re faulted). However it does guarantee that the page
1982 * won't be freed completely. And mostly callers simply care that the page
1983 * contains data that was valid *at some point in time*. Typically, an IO
1984 * or similar operation cannot guarantee anything stronger anyway because
1985 * locks can't be held over the syscall boundary.
1987 * If write=0, the page must not be written to. If the page is written to,
1988 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1989 * after the page is finished with, and before put_page is called.
1991 * get_user_pages is typically used for fewer-copy IO operations, to get a
1992 * handle on the memory by some means other than accesses via the user virtual
1993 * addresses. The pages may be submitted for DMA to devices or accessed via
1994 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1995 * use the correct cache flushing APIs.
1997 * See also get_user_pages_fast, for performance critical applications.
1999 long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
2000 unsigned long start, unsigned long nr_pages, int write,
2001 int force, struct page **pages, struct vm_area_struct **vmas)
2003 int flags = FOLL_TOUCH;
2008 flags |= FOLL_WRITE;
2010 flags |= FOLL_FORCE;
2012 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
2015 EXPORT_SYMBOL(get_user_pages);
2018 * get_dump_page() - pin user page in memory while writing it to core dump
2019 * @addr: user address
2021 * Returns struct page pointer of user page pinned for dump,
2022 * to be freed afterwards by page_cache_release() or put_page().
2024 * Returns NULL on any kind of failure - a hole must then be inserted into
2025 * the corefile, to preserve alignment with its headers; and also returns
2026 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
2027 * allowing a hole to be left in the corefile to save diskspace.
2029 * Called without mmap_sem, but after all other threads have been killed.
2031 #ifdef CONFIG_ELF_CORE
2032 struct page *get_dump_page(unsigned long addr)
2034 struct vm_area_struct *vma;
2037 if (__get_user_pages(current, current->mm, addr, 1,
2038 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
2041 flush_cache_page(vma, addr, page_to_pfn(page));
2044 #endif /* CONFIG_ELF_CORE */
2046 pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
2049 pgd_t * pgd = pgd_offset(mm, addr);
2050 pud_t * pud = pud_alloc(mm, pgd, addr);
2052 pmd_t * pmd = pmd_alloc(mm, pud, addr);
2054 VM_BUG_ON(pmd_trans_huge(*pmd));
2055 return pte_alloc_map_lock(mm, pmd, addr, ptl);
2062 * This is the old fallback for page remapping.
2064 * For historical reasons, it only allows reserved pages. Only
2065 * old drivers should use this, and they needed to mark their
2066 * pages reserved for the old functions anyway.
2068 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
2069 struct page *page, pgprot_t prot)
2071 struct mm_struct *mm = vma->vm_mm;
2080 flush_dcache_page(page);
2081 pte = get_locked_pte(mm, addr, &ptl);
2085 if (!pte_none(*pte))
2088 /* Ok, finally just insert the thing.. */
2090 inc_mm_counter_fast(mm, MM_FILEPAGES);
2091 page_add_file_rmap(page);
2092 set_pte_at(mm, addr, pte, mk_pte(page, prot));
2095 pte_unmap_unlock(pte, ptl);
2098 pte_unmap_unlock(pte, ptl);
2104 * vm_insert_page - insert single page into user vma
2105 * @vma: user vma to map to
2106 * @addr: target user address of this page
2107 * @page: source kernel page
2109 * This allows drivers to insert individual pages they've allocated
2112 * The page has to be a nice clean _individual_ kernel allocation.
2113 * If you allocate a compound page, you need to have marked it as
2114 * such (__GFP_COMP), or manually just split the page up yourself
2115 * (see split_page()).
2117 * NOTE! Traditionally this was done with "remap_pfn_range()" which
2118 * took an arbitrary page protection parameter. This doesn't allow
2119 * that. Your vma protection will have to be set up correctly, which
2120 * means that if you want a shared writable mapping, you'd better
2121 * ask for a shared writable mapping!
2123 * The page does not need to be reserved.
2125 * Usually this function is called from f_op->mmap() handler
2126 * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
2127 * Caller must set VM_MIXEDMAP on vma if it wants to call this
2128 * function from other places, for example from page-fault handler.
2130 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
2133 if (addr < vma->vm_start || addr >= vma->vm_end)
2135 if (!page_count(page))
2137 if (!(vma->vm_flags & VM_MIXEDMAP)) {
2138 BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem));
2139 BUG_ON(vma->vm_flags & VM_PFNMAP);
2140 vma->vm_flags |= VM_MIXEDMAP;
2142 return insert_page(vma, addr, page, vma->vm_page_prot);
2144 EXPORT_SYMBOL(vm_insert_page);
2146 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2147 unsigned long pfn, pgprot_t prot)
2149 struct mm_struct *mm = vma->vm_mm;
2155 pte = get_locked_pte(mm, addr, &ptl);
2159 if (!pte_none(*pte))
2162 /* Ok, finally just insert the thing.. */
2163 entry = pte_mkspecial(pfn_pte(pfn, prot));
2164 set_pte_at(mm, addr, pte, entry);
2165 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
2169 pte_unmap_unlock(pte, ptl);
2175 * vm_insert_pfn - insert single pfn into user vma
2176 * @vma: user vma to map to
2177 * @addr: target user address of this page
2178 * @pfn: source kernel pfn
2180 * Similar to vm_insert_page, this allows drivers to insert individual pages
2181 * they've allocated into a user vma. Same comments apply.
2183 * This function should only be called from a vm_ops->fault handler, and
2184 * in that case the handler should return NULL.
2186 * vma cannot be a COW mapping.
2188 * As this is called only for pages that do not currently exist, we
2189 * do not need to flush old virtual caches or the TLB.
2191 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2195 pgprot_t pgprot = vma->vm_page_prot;
2197 * Technically, architectures with pte_special can avoid all these
2198 * restrictions (same for remap_pfn_range). However we would like
2199 * consistency in testing and feature parity among all, so we should
2200 * try to keep these invariants in place for everybody.
2202 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
2203 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
2204 (VM_PFNMAP|VM_MIXEDMAP));
2205 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
2206 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
2208 if (addr < vma->vm_start || addr >= vma->vm_end)
2210 if (track_pfn_insert(vma, &pgprot, pfn))
2213 ret = insert_pfn(vma, addr, pfn, pgprot);
2217 EXPORT_SYMBOL(vm_insert_pfn);
2219 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2222 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
2224 if (addr < vma->vm_start || addr >= vma->vm_end)
2228 * If we don't have pte special, then we have to use the pfn_valid()
2229 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
2230 * refcount the page if pfn_valid is true (hence insert_page rather
2231 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
2232 * without pte special, it would there be refcounted as a normal page.
2234 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
2237 page = pfn_to_page(pfn);
2238 return insert_page(vma, addr, page, vma->vm_page_prot);
2240 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
2242 EXPORT_SYMBOL(vm_insert_mixed);
2245 * maps a range of physical memory into the requested pages. the old
2246 * mappings are removed. any references to nonexistent pages results
2247 * in null mappings (currently treated as "copy-on-access")
2249 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
2250 unsigned long addr, unsigned long end,
2251 unsigned long pfn, pgprot_t prot)
2256 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
2259 arch_enter_lazy_mmu_mode();
2261 BUG_ON(!pte_none(*pte));
2262 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
2264 } while (pte++, addr += PAGE_SIZE, addr != end);
2265 arch_leave_lazy_mmu_mode();
2266 pte_unmap_unlock(pte - 1, ptl);
2270 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
2271 unsigned long addr, unsigned long end,
2272 unsigned long pfn, pgprot_t prot)
2277 pfn -= addr >> PAGE_SHIFT;
2278 pmd = pmd_alloc(mm, pud, addr);
2281 VM_BUG_ON(pmd_trans_huge(*pmd));
2283 next = pmd_addr_end(addr, end);
2284 if (remap_pte_range(mm, pmd, addr, next,
2285 pfn + (addr >> PAGE_SHIFT), prot))
2287 } while (pmd++, addr = next, addr != end);
2291 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
2292 unsigned long addr, unsigned long end,
2293 unsigned long pfn, pgprot_t prot)
2298 pfn -= addr >> PAGE_SHIFT;
2299 pud = pud_alloc(mm, pgd, addr);
2303 next = pud_addr_end(addr, end);
2304 if (remap_pmd_range(mm, pud, addr, next,
2305 pfn + (addr >> PAGE_SHIFT), prot))
2307 } while (pud++, addr = next, addr != end);
2312 * remap_pfn_range - remap kernel memory to userspace
2313 * @vma: user vma to map to
2314 * @addr: target user address to start at
2315 * @pfn: physical address of kernel memory
2316 * @size: size of map area
2317 * @prot: page protection flags for this mapping
2319 * Note: this is only safe if the mm semaphore is held when called.
2321 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
2322 unsigned long pfn, unsigned long size, pgprot_t prot)
2326 unsigned long end = addr + PAGE_ALIGN(size);
2327 struct mm_struct *mm = vma->vm_mm;
2331 * Physically remapped pages are special. Tell the
2332 * rest of the world about it:
2333 * VM_IO tells people not to look at these pages
2334 * (accesses can have side effects).
2335 * VM_PFNMAP tells the core MM that the base pages are just
2336 * raw PFN mappings, and do not have a "struct page" associated
2339 * Disable vma merging and expanding with mremap().
2341 * Omit vma from core dump, even when VM_IO turned off.
2343 * There's a horrible special case to handle copy-on-write
2344 * behaviour that some programs depend on. We mark the "original"
2345 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
2346 * See vm_normal_page() for details.
2348 if (is_cow_mapping(vma->vm_flags)) {
2349 if (addr != vma->vm_start || end != vma->vm_end)
2351 vma->vm_pgoff = pfn;
2354 err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
2358 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
2360 BUG_ON(addr >= end);
2361 pfn -= addr >> PAGE_SHIFT;
2362 pgd = pgd_offset(mm, addr);
2363 flush_cache_range(vma, addr, end);
2365 next = pgd_addr_end(addr, end);
2366 err = remap_pud_range(mm, pgd, addr, next,
2367 pfn + (addr >> PAGE_SHIFT), prot);
2370 } while (pgd++, addr = next, addr != end);
2373 untrack_pfn(vma, pfn, PAGE_ALIGN(size));
2377 EXPORT_SYMBOL(remap_pfn_range);
2379 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
2380 unsigned long addr, unsigned long end,
2381 pte_fn_t fn, void *data)
2386 spinlock_t *uninitialized_var(ptl);
2388 pte = (mm == &init_mm) ?
2389 pte_alloc_kernel(pmd, addr) :
2390 pte_alloc_map_lock(mm, pmd, addr, &ptl);
2394 BUG_ON(pmd_huge(*pmd));
2396 arch_enter_lazy_mmu_mode();
2398 token = pmd_pgtable(*pmd);
2401 err = fn(pte++, token, addr, data);
2404 } while (addr += PAGE_SIZE, addr != end);
2406 arch_leave_lazy_mmu_mode();
2409 pte_unmap_unlock(pte-1, ptl);
2413 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
2414 unsigned long addr, unsigned long end,
2415 pte_fn_t fn, void *data)
2421 BUG_ON(pud_huge(*pud));
2423 pmd = pmd_alloc(mm, pud, addr);
2427 next = pmd_addr_end(addr, end);
2428 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
2431 } while (pmd++, addr = next, addr != end);
2435 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
2436 unsigned long addr, unsigned long end,
2437 pte_fn_t fn, void *data)
2443 pud = pud_alloc(mm, pgd, addr);
2447 next = pud_addr_end(addr, end);
2448 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
2451 } while (pud++, addr = next, addr != end);
2456 * Scan a region of virtual memory, filling in page tables as necessary
2457 * and calling a provided function on each leaf page table.
2459 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2460 unsigned long size, pte_fn_t fn, void *data)
2464 unsigned long end = addr + size;
2467 BUG_ON(addr >= end);
2468 pgd = pgd_offset(mm, addr);
2470 next = pgd_addr_end(addr, end);
2471 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2474 } while (pgd++, addr = next, addr != end);
2478 EXPORT_SYMBOL_GPL(apply_to_page_range);
2481 * handle_pte_fault chooses page fault handler according to an entry
2482 * which was read non-atomically. Before making any commitment, on
2483 * those architectures or configurations (e.g. i386 with PAE) which
2484 * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
2485 * must check under lock before unmapping the pte and proceeding
2486 * (but do_wp_page is only called after already making such a check;
2487 * and do_anonymous_page can safely check later on).
2489 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2490 pte_t *page_table, pte_t orig_pte)
2493 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2494 if (sizeof(pte_t) > sizeof(unsigned long)) {
2495 spinlock_t *ptl = pte_lockptr(mm, pmd);
2497 same = pte_same(*page_table, orig_pte);
2501 pte_unmap(page_table);
2505 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2508 * If the source page was a PFN mapping, we don't have
2509 * a "struct page" for it. We do a best-effort copy by
2510 * just copying from the original user address. If that
2511 * fails, we just zero-fill it. Live with it.
2513 if (unlikely(!src)) {
2514 void *kaddr = kmap_atomic(dst);
2515 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2518 * This really shouldn't fail, because the page is there
2519 * in the page tables. But it might just be unreadable,
2520 * in which case we just give up and fill the result with
2523 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2525 kunmap_atomic(kaddr);
2526 flush_dcache_page(dst);
2528 copy_user_highpage(dst, src, va, vma);
2532 * This routine handles present pages, when users try to write
2533 * to a shared page. It is done by copying the page to a new address
2534 * and decrementing the shared-page counter for the old page.
2536 * Note that this routine assumes that the protection checks have been
2537 * done by the caller (the low-level page fault routine in most cases).
2538 * Thus we can safely just mark it writable once we've done any necessary
2541 * We also mark the page dirty at this point even though the page will
2542 * change only once the write actually happens. This avoids a few races,
2543 * and potentially makes it more efficient.
2545 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2546 * but allow concurrent faults), with pte both mapped and locked.
2547 * We return with mmap_sem still held, but pte unmapped and unlocked.
2549 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2550 unsigned long address, pte_t *page_table, pmd_t *pmd,
2551 spinlock_t *ptl, pte_t orig_pte)
2554 struct page *old_page, *new_page = NULL;
2557 int page_mkwrite = 0;
2558 struct page *dirty_page = NULL;
2559 unsigned long mmun_start = 0; /* For mmu_notifiers */
2560 unsigned long mmun_end = 0; /* For mmu_notifiers */
2562 old_page = vm_normal_page(vma, address, orig_pte);
2565 * VM_MIXEDMAP !pfn_valid() case
2567 * We should not cow pages in a shared writeable mapping.
2568 * Just mark the pages writable as we can't do any dirty
2569 * accounting on raw pfn maps.
2571 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2572 (VM_WRITE|VM_SHARED))
2578 * Take out anonymous pages first, anonymous shared vmas are
2579 * not dirty accountable.
2581 if (PageAnon(old_page) && !PageKsm(old_page)) {
2582 if (!trylock_page(old_page)) {
2583 page_cache_get(old_page);
2584 pte_unmap_unlock(page_table, ptl);
2585 lock_page(old_page);
2586 page_table = pte_offset_map_lock(mm, pmd, address,
2588 if (!pte_same(*page_table, orig_pte)) {
2589 unlock_page(old_page);
2592 page_cache_release(old_page);
2594 if (reuse_swap_page(old_page)) {
2596 * The page is all ours. Move it to our anon_vma so
2597 * the rmap code will not search our parent or siblings.
2598 * Protected against the rmap code by the page lock.
2600 page_move_anon_rmap(old_page, vma, address);
2601 unlock_page(old_page);
2604 unlock_page(old_page);
2605 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2606 (VM_WRITE|VM_SHARED))) {
2608 * Only catch write-faults on shared writable pages,
2609 * read-only shared pages can get COWed by
2610 * get_user_pages(.write=1, .force=1).
2612 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2613 struct vm_fault vmf;
2616 vmf.virtual_address = (void __user *)(address &
2618 vmf.pgoff = old_page->index;
2619 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2620 vmf.page = old_page;
2623 * Notify the address space that the page is about to
2624 * become writable so that it can prohibit this or wait
2625 * for the page to get into an appropriate state.
2627 * We do this without the lock held, so that it can
2628 * sleep if it needs to.
2630 page_cache_get(old_page);
2631 pte_unmap_unlock(page_table, ptl);
2633 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2635 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2637 goto unwritable_page;
2639 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2640 lock_page(old_page);
2641 if (!old_page->mapping) {
2642 ret = 0; /* retry the fault */
2643 unlock_page(old_page);
2644 goto unwritable_page;
2647 VM_BUG_ON(!PageLocked(old_page));
2650 * Since we dropped the lock we need to revalidate
2651 * the PTE as someone else may have changed it. If
2652 * they did, we just return, as we can count on the
2653 * MMU to tell us if they didn't also make it writable.
2655 page_table = pte_offset_map_lock(mm, pmd, address,
2657 if (!pte_same(*page_table, orig_pte)) {
2658 unlock_page(old_page);
2664 dirty_page = old_page;
2665 get_page(dirty_page);
2668 flush_cache_page(vma, address, pte_pfn(orig_pte));
2669 entry = pte_mkyoung(orig_pte);
2670 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2671 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2672 update_mmu_cache(vma, address, page_table);
2673 pte_unmap_unlock(page_table, ptl);
2674 ret |= VM_FAULT_WRITE;
2680 * Yes, Virginia, this is actually required to prevent a race
2681 * with clear_page_dirty_for_io() from clearing the page dirty
2682 * bit after it clear all dirty ptes, but before a racing
2683 * do_wp_page installs a dirty pte.
2685 * __do_fault is protected similarly.
2687 if (!page_mkwrite) {
2688 wait_on_page_locked(dirty_page);
2689 set_page_dirty_balance(dirty_page, page_mkwrite);
2690 /* file_update_time outside page_lock */
2692 file_update_time(vma->vm_file);
2694 put_page(dirty_page);
2696 struct address_space *mapping = dirty_page->mapping;
2698 set_page_dirty(dirty_page);
2699 unlock_page(dirty_page);
2700 page_cache_release(dirty_page);
2703 * Some device drivers do not set page.mapping
2704 * but still dirty their pages
2706 balance_dirty_pages_ratelimited(mapping);
2714 * Ok, we need to copy. Oh, well..
2716 page_cache_get(old_page);
2718 pte_unmap_unlock(page_table, ptl);
2720 if (unlikely(anon_vma_prepare(vma)))
2723 if (is_zero_pfn(pte_pfn(orig_pte))) {
2724 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2728 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2731 cow_user_page(new_page, old_page, address, vma);
2733 __SetPageUptodate(new_page);
2735 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2738 mmun_start = address & PAGE_MASK;
2739 mmun_end = mmun_start + PAGE_SIZE;
2740 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2743 * Re-check the pte - we dropped the lock
2745 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2746 if (likely(pte_same(*page_table, orig_pte))) {
2748 if (!PageAnon(old_page)) {
2749 dec_mm_counter_fast(mm, MM_FILEPAGES);
2750 inc_mm_counter_fast(mm, MM_ANONPAGES);
2753 inc_mm_counter_fast(mm, MM_ANONPAGES);
2754 flush_cache_page(vma, address, pte_pfn(orig_pte));
2755 entry = mk_pte(new_page, vma->vm_page_prot);
2756 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2758 * Clear the pte entry and flush it first, before updating the
2759 * pte with the new entry. This will avoid a race condition
2760 * seen in the presence of one thread doing SMC and another
2763 ptep_clear_flush(vma, address, page_table);
2764 page_add_new_anon_rmap(new_page, vma, address);
2766 * We call the notify macro here because, when using secondary
2767 * mmu page tables (such as kvm shadow page tables), we want the
2768 * new page to be mapped directly into the secondary page table.
2770 set_pte_at_notify(mm, address, page_table, entry);
2771 update_mmu_cache(vma, address, page_table);
2774 * Only after switching the pte to the new page may
2775 * we remove the mapcount here. Otherwise another
2776 * process may come and find the rmap count decremented
2777 * before the pte is switched to the new page, and
2778 * "reuse" the old page writing into it while our pte
2779 * here still points into it and can be read by other
2782 * The critical issue is to order this
2783 * page_remove_rmap with the ptp_clear_flush above.
2784 * Those stores are ordered by (if nothing else,)
2785 * the barrier present in the atomic_add_negative
2786 * in page_remove_rmap.
2788 * Then the TLB flush in ptep_clear_flush ensures that
2789 * no process can access the old page before the
2790 * decremented mapcount is visible. And the old page
2791 * cannot be reused until after the decremented
2792 * mapcount is visible. So transitively, TLBs to
2793 * old page will be flushed before it can be reused.
2795 page_remove_rmap(old_page);
2798 /* Free the old page.. */
2799 new_page = old_page;
2800 ret |= VM_FAULT_WRITE;
2802 mem_cgroup_uncharge_page(new_page);
2805 page_cache_release(new_page);
2807 pte_unmap_unlock(page_table, ptl);
2808 if (mmun_end > mmun_start)
2809 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2812 * Don't let another task, with possibly unlocked vma,
2813 * keep the mlocked page.
2815 if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) {
2816 lock_page(old_page); /* LRU manipulation */
2817 munlock_vma_page(old_page);
2818 unlock_page(old_page);
2820 page_cache_release(old_page);
2824 page_cache_release(new_page);
2827 page_cache_release(old_page);
2828 return VM_FAULT_OOM;
2831 page_cache_release(old_page);
2835 static void unmap_mapping_range_vma(struct vm_area_struct *vma,
2836 unsigned long start_addr, unsigned long end_addr,
2837 struct zap_details *details)
2839 zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
2842 static inline void unmap_mapping_range_tree(struct rb_root *root,
2843 struct zap_details *details)
2845 struct vm_area_struct *vma;
2846 pgoff_t vba, vea, zba, zea;
2848 vma_interval_tree_foreach(vma, root,
2849 details->first_index, details->last_index) {
2851 vba = vma->vm_pgoff;
2852 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2853 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2854 zba = details->first_index;
2857 zea = details->last_index;
2861 unmap_mapping_range_vma(vma,
2862 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2863 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2868 static inline void unmap_mapping_range_list(struct list_head *head,
2869 struct zap_details *details)
2871 struct vm_area_struct *vma;
2874 * In nonlinear VMAs there is no correspondence between virtual address
2875 * offset and file offset. So we must perform an exhaustive search
2876 * across *all* the pages in each nonlinear VMA, not just the pages
2877 * whose virtual address lies outside the file truncation point.
2879 list_for_each_entry(vma, head, shared.nonlinear) {
2880 details->nonlinear_vma = vma;
2881 unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
2886 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2887 * @mapping: the address space containing mmaps to be unmapped.
2888 * @holebegin: byte in first page to unmap, relative to the start of
2889 * the underlying file. This will be rounded down to a PAGE_SIZE
2890 * boundary. Note that this is different from truncate_pagecache(), which
2891 * must keep the partial page. In contrast, we must get rid of
2893 * @holelen: size of prospective hole in bytes. This will be rounded
2894 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2896 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2897 * but 0 when invalidating pagecache, don't throw away private data.
2899 void unmap_mapping_range(struct address_space *mapping,
2900 loff_t const holebegin, loff_t const holelen, int even_cows)
2902 struct zap_details details;
2903 pgoff_t hba = holebegin >> PAGE_SHIFT;
2904 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2906 /* Check for overflow. */
2907 if (sizeof(holelen) > sizeof(hlen)) {
2909 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2910 if (holeend & ~(long long)ULONG_MAX)
2911 hlen = ULONG_MAX - hba + 1;
2914 details.check_mapping = even_cows? NULL: mapping;
2915 details.nonlinear_vma = NULL;
2916 details.first_index = hba;
2917 details.last_index = hba + hlen - 1;
2918 if (details.last_index < details.first_index)
2919 details.last_index = ULONG_MAX;
2922 mutex_lock(&mapping->i_mmap_mutex);
2923 if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
2924 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2925 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2926 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2927 mutex_unlock(&mapping->i_mmap_mutex);
2929 EXPORT_SYMBOL(unmap_mapping_range);
2932 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2933 * but allow concurrent faults), and pte mapped but not yet locked.
2934 * We return with mmap_sem still held, but pte unmapped and unlocked.
2936 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2937 unsigned long address, pte_t *page_table, pmd_t *pmd,
2938 unsigned int flags, pte_t orig_pte)
2941 struct page *page, *swapcache = NULL;
2945 struct mem_cgroup *ptr;
2949 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
2952 entry = pte_to_swp_entry(orig_pte);
2953 if (unlikely(non_swap_entry(entry))) {
2954 if (is_migration_entry(entry)) {
2955 migration_entry_wait(mm, pmd, address);
2956 } else if (is_hwpoison_entry(entry)) {
2957 ret = VM_FAULT_HWPOISON;
2959 print_bad_pte(vma, address, orig_pte, NULL);
2960 ret = VM_FAULT_SIGBUS;
2964 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2965 page = lookup_swap_cache(entry);
2967 page = swapin_readahead(entry,
2968 GFP_HIGHUSER_MOVABLE, vma, address);
2971 * Back out if somebody else faulted in this pte
2972 * while we released the pte lock.
2974 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2975 if (likely(pte_same(*page_table, orig_pte)))
2977 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2981 /* Had to read the page from swap area: Major fault */
2982 ret = VM_FAULT_MAJOR;
2983 count_vm_event(PGMAJFAULT);
2984 mem_cgroup_count_vm_event(mm, PGMAJFAULT);
2985 } else if (PageHWPoison(page)) {
2987 * hwpoisoned dirty swapcache pages are kept for killing
2988 * owner processes (which may be unknown at hwpoison time)
2990 ret = VM_FAULT_HWPOISON;
2991 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2995 locked = lock_page_or_retry(page, mm, flags);
2997 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2999 ret |= VM_FAULT_RETRY;
3004 * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
3005 * release the swapcache from under us. The page pin, and pte_same
3006 * test below, are not enough to exclude that. Even if it is still
3007 * swapcache, we need to check that the page's swap has not changed.
3009 if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
3013 page = ksm_might_need_to_copy(page, vma, address);
3014 if (unlikely(!page)) {
3020 if (page == swapcache)
3023 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
3029 * Back out if somebody else already faulted in this pte.
3031 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3032 if (unlikely(!pte_same(*page_table, orig_pte)))
3035 if (unlikely(!PageUptodate(page))) {
3036 ret = VM_FAULT_SIGBUS;
3041 * The page isn't present yet, go ahead with the fault.
3043 * Be careful about the sequence of operations here.
3044 * To get its accounting right, reuse_swap_page() must be called
3045 * while the page is counted on swap but not yet in mapcount i.e.
3046 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
3047 * must be called after the swap_free(), or it will never succeed.
3048 * Because delete_from_swap_page() may be called by reuse_swap_page(),
3049 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
3050 * in page->private. In this case, a record in swap_cgroup is silently
3051 * discarded at swap_free().
3054 inc_mm_counter_fast(mm, MM_ANONPAGES);
3055 dec_mm_counter_fast(mm, MM_SWAPENTS);
3056 pte = mk_pte(page, vma->vm_page_prot);
3057 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
3058 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
3059 flags &= ~FAULT_FLAG_WRITE;
3060 ret |= VM_FAULT_WRITE;
3063 flush_icache_page(vma, page);
3064 set_pte_at(mm, address, page_table, pte);
3065 if (swapcache) /* ksm created a completely new copy */
3066 page_add_new_anon_rmap(page, vma, address);
3068 do_page_add_anon_rmap(page, vma, address, exclusive);
3069 /* It's better to call commit-charge after rmap is established */
3070 mem_cgroup_commit_charge_swapin(page, ptr);
3073 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
3074 try_to_free_swap(page);
3078 * Hold the lock to avoid the swap entry to be reused
3079 * until we take the PT lock for the pte_same() check
3080 * (to avoid false positives from pte_same). For
3081 * further safety release the lock after the swap_free
3082 * so that the swap count won't change under a
3083 * parallel locked swapcache.
3085 unlock_page(swapcache);
3086 page_cache_release(swapcache);
3089 if (flags & FAULT_FLAG_WRITE) {
3090 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
3091 if (ret & VM_FAULT_ERROR)
3092 ret &= VM_FAULT_ERROR;
3096 /* No need to invalidate - it was non-present before */
3097 update_mmu_cache(vma, address, page_table);
3099 pte_unmap_unlock(page_table, ptl);
3103 mem_cgroup_cancel_charge_swapin(ptr);
3104 pte_unmap_unlock(page_table, ptl);
3108 page_cache_release(page);
3110 unlock_page(swapcache);
3111 page_cache_release(swapcache);
3117 * This is like a special single-page "expand_{down|up}wards()",
3118 * except we must first make sure that 'address{-|+}PAGE_SIZE'
3119 * doesn't hit another vma.
3121 static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
3123 address &= PAGE_MASK;
3124 if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
3125 struct vm_area_struct *prev = vma->vm_prev;
3128 * Is there a mapping abutting this one below?
3130 * That's only ok if it's the same stack mapping
3131 * that has gotten split..
3133 if (prev && prev->vm_end == address)
3134 return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
3136 expand_downwards(vma, address - PAGE_SIZE);
3138 if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
3139 struct vm_area_struct *next = vma->vm_next;
3141 /* As VM_GROWSDOWN but s/below/above/ */
3142 if (next && next->vm_start == address + PAGE_SIZE)
3143 return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
3145 expand_upwards(vma, address + PAGE_SIZE);
3151 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3152 * but allow concurrent faults), and pte mapped but not yet locked.
3153 * We return with mmap_sem still held, but pte unmapped and unlocked.
3155 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
3156 unsigned long address, pte_t *page_table, pmd_t *pmd,
3163 pte_unmap(page_table);
3165 /* Check if we need to add a guard page to the stack */
3166 if (check_stack_guard_page(vma, address) < 0)
3167 return VM_FAULT_SIGBUS;
3169 /* Use the zero-page for reads */
3170 if (!(flags & FAULT_FLAG_WRITE)) {
3171 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
3172 vma->vm_page_prot));
3173 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3174 if (!pte_none(*page_table))
3179 /* Allocate our own private page. */
3180 if (unlikely(anon_vma_prepare(vma)))
3182 page = alloc_zeroed_user_highpage_movable(vma, address);
3185 __SetPageUptodate(page);
3187 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
3190 entry = mk_pte(page, vma->vm_page_prot);
3191 if (vma->vm_flags & VM_WRITE)
3192 entry = pte_mkwrite(pte_mkdirty(entry));
3194 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3195 if (!pte_none(*page_table))
3198 inc_mm_counter_fast(mm, MM_ANONPAGES);
3199 page_add_new_anon_rmap(page, vma, address);
3201 set_pte_at(mm, address, page_table, entry);
3203 /* No need to invalidate - it was non-present before */
3204 update_mmu_cache(vma, address, page_table);
3206 pte_unmap_unlock(page_table, ptl);
3209 mem_cgroup_uncharge_page(page);
3210 page_cache_release(page);
3213 page_cache_release(page);
3215 return VM_FAULT_OOM;
3219 * __do_fault() tries to create a new page mapping. It aggressively
3220 * tries to share with existing pages, but makes a separate copy if
3221 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
3222 * the next page fault.
3224 * As this is called only for pages that do not currently exist, we
3225 * do not need to flush old virtual caches or the TLB.
3227 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3228 * but allow concurrent faults), and pte neither mapped nor locked.
3229 * We return with mmap_sem still held, but pte unmapped and unlocked.
3231 static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3232 unsigned long address, pmd_t *pmd,
3233 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
3238 struct page *cow_page;
3241 struct page *dirty_page = NULL;
3242 struct vm_fault vmf;
3244 int page_mkwrite = 0;
3247 * If we do COW later, allocate page befor taking lock_page()
3248 * on the file cache page. This will reduce lock holding time.
3250 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3252 if (unlikely(anon_vma_prepare(vma)))
3253 return VM_FAULT_OOM;
3255 cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
3257 return VM_FAULT_OOM;
3259 if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) {
3260 page_cache_release(cow_page);
3261 return VM_FAULT_OOM;
3266 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
3271 ret = vma->vm_ops->fault(vma, &vmf);
3272 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
3276 if (unlikely(PageHWPoison(vmf.page))) {
3277 if (ret & VM_FAULT_LOCKED)
3278 unlock_page(vmf.page);
3279 ret = VM_FAULT_HWPOISON;
3284 * For consistency in subsequent calls, make the faulted page always
3287 if (unlikely(!(ret & VM_FAULT_LOCKED)))
3288 lock_page(vmf.page);
3290 VM_BUG_ON(!PageLocked(vmf.page));
3293 * Should we do an early C-O-W break?
3296 if (flags & FAULT_FLAG_WRITE) {
3297 if (!(vma->vm_flags & VM_SHARED)) {
3300 copy_user_highpage(page, vmf.page, address, vma);
3301 __SetPageUptodate(page);
3304 * If the page will be shareable, see if the backing
3305 * address space wants to know that the page is about
3306 * to become writable
3308 if (vma->vm_ops->page_mkwrite) {
3312 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
3313 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
3315 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
3317 goto unwritable_page;
3319 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
3321 if (!page->mapping) {
3322 ret = 0; /* retry the fault */
3324 goto unwritable_page;
3327 VM_BUG_ON(!PageLocked(page));
3334 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3337 * This silly early PAGE_DIRTY setting removes a race
3338 * due to the bad i386 page protection. But it's valid
3339 * for other architectures too.
3341 * Note that if FAULT_FLAG_WRITE is set, we either now have
3342 * an exclusive copy of the page, or this is a shared mapping,
3343 * so we can make it writable and dirty to avoid having to
3344 * handle that later.
3346 /* Only go through if we didn't race with anybody else... */
3347 if (likely(pte_same(*page_table, orig_pte))) {
3348 flush_icache_page(vma, page);
3349 entry = mk_pte(page, vma->vm_page_prot);
3350 if (flags & FAULT_FLAG_WRITE)
3351 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
3353 inc_mm_counter_fast(mm, MM_ANONPAGES);
3354 page_add_new_anon_rmap(page, vma, address);
3356 inc_mm_counter_fast(mm, MM_FILEPAGES);
3357 page_add_file_rmap(page);
3358 if (flags & FAULT_FLAG_WRITE) {
3360 get_page(dirty_page);
3363 set_pte_at(mm, address, page_table, entry);
3365 /* no need to invalidate: a not-present page won't be cached */
3366 update_mmu_cache(vma, address, page_table);
3369 mem_cgroup_uncharge_page(cow_page);
3371 page_cache_release(page);
3373 anon = 1; /* no anon but release faulted_page */
3376 pte_unmap_unlock(page_table, ptl);
3379 struct address_space *mapping = page->mapping;
3382 if (set_page_dirty(dirty_page))
3384 unlock_page(dirty_page);
3385 put_page(dirty_page);
3386 if ((dirtied || page_mkwrite) && mapping) {
3388 * Some device drivers do not set page.mapping but still
3391 balance_dirty_pages_ratelimited(mapping);
3394 /* file_update_time outside page_lock */
3395 if (vma->vm_file && !page_mkwrite)
3396 file_update_time(vma->vm_file);
3398 unlock_page(vmf.page);
3400 page_cache_release(vmf.page);
3406 page_cache_release(page);
3409 /* fs's fault handler get error */
3411 mem_cgroup_uncharge_page(cow_page);
3412 page_cache_release(cow_page);
3417 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3418 unsigned long address, pte_t *page_table, pmd_t *pmd,
3419 unsigned int flags, pte_t orig_pte)
3421 pgoff_t pgoff = (((address & PAGE_MASK)
3422 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3424 pte_unmap(page_table);
3425 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3429 * Fault of a previously existing named mapping. Repopulate the pte
3430 * from the encoded file_pte if possible. This enables swappable
3433 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3434 * but allow concurrent faults), and pte mapped but not yet locked.
3435 * We return with mmap_sem still held, but pte unmapped and unlocked.
3437 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3438 unsigned long address, pte_t *page_table, pmd_t *pmd,
3439 unsigned int flags, pte_t orig_pte)
3443 flags |= FAULT_FLAG_NONLINEAR;
3445 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3448 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3450 * Page table corrupted: show pte and kill process.
3452 print_bad_pte(vma, address, orig_pte, NULL);
3453 return VM_FAULT_SIGBUS;
3456 pgoff = pte_to_pgoff(orig_pte);
3457 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3460 int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
3461 unsigned long addr, int current_nid)
3465 count_vm_numa_event(NUMA_HINT_FAULTS);
3466 if (current_nid == numa_node_id())
3467 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
3469 return mpol_misplaced(page, vma, addr);
3472 int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3473 unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
3475 struct page *page = NULL;
3477 int current_nid = -1;
3479 bool migrated = false;
3482 * The "pte" at this point cannot be used safely without
3483 * validation through pte_unmap_same(). It's of NUMA type but
3484 * the pfn may be screwed if the read is non atomic.
3486 * ptep_modify_prot_start is not called as this is clearing
3487 * the _PAGE_NUMA bit and it is not really expected that there
3488 * would be concurrent hardware modifications to the PTE.
3490 ptl = pte_lockptr(mm, pmd);
3492 if (unlikely(!pte_same(*ptep, pte))) {
3493 pte_unmap_unlock(ptep, ptl);
3497 pte = pte_mknonnuma(pte);
3498 set_pte_at(mm, addr, ptep, pte);
3499 update_mmu_cache(vma, addr, ptep);
3501 page = vm_normal_page(vma, addr, pte);
3503 pte_unmap_unlock(ptep, ptl);
3507 current_nid = page_to_nid(page);
3508 target_nid = numa_migrate_prep(page, vma, addr, current_nid);
3509 pte_unmap_unlock(ptep, ptl);
3510 if (target_nid == -1) {
3512 * Account for the fault against the current node if it not
3513 * being replaced regardless of where the page is located.
3515 current_nid = numa_node_id();
3520 /* Migrate to the requested node */
3521 migrated = migrate_misplaced_page(page, target_nid);
3523 current_nid = target_nid;
3526 if (current_nid != -1)
3527 task_numa_fault(current_nid, 1, migrated);
3531 /* NUMA hinting page fault entry point for regular pmds */
3532 #ifdef CONFIG_NUMA_BALANCING
3533 static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3534 unsigned long addr, pmd_t *pmdp)
3537 pte_t *pte, *orig_pte;
3538 unsigned long _addr = addr & PMD_MASK;
3539 unsigned long offset;
3542 int local_nid = numa_node_id();
3544 spin_lock(&mm->page_table_lock);
3546 if (pmd_numa(pmd)) {
3547 set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd));
3550 spin_unlock(&mm->page_table_lock);
3555 /* we're in a page fault so some vma must be in the range */
3557 BUG_ON(vma->vm_start >= _addr + PMD_SIZE);
3558 offset = max(_addr, vma->vm_start) & ~PMD_MASK;
3559 VM_BUG_ON(offset >= PMD_SIZE);
3560 orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl);
3561 pte += offset >> PAGE_SHIFT;
3562 for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) {
3563 pte_t pteval = *pte;
3565 int curr_nid = local_nid;
3568 if (!pte_present(pteval))
3570 if (!pte_numa(pteval))
3572 if (addr >= vma->vm_end) {
3573 vma = find_vma(mm, addr);
3574 /* there's a pte present so there must be a vma */
3576 BUG_ON(addr < vma->vm_start);
3578 if (pte_numa(pteval)) {
3579 pteval = pte_mknonnuma(pteval);
3580 set_pte_at(mm, addr, pte, pteval);
3582 page = vm_normal_page(vma, addr, pteval);
3583 if (unlikely(!page))
3585 /* only check non-shared pages */
3586 if (unlikely(page_mapcount(page) != 1))
3590 * Note that the NUMA fault is later accounted to either
3591 * the node that is currently running or where the page is
3594 curr_nid = local_nid;
3595 target_nid = numa_migrate_prep(page, vma, addr,
3597 if (target_nid == -1) {
3602 /* Migrate to the requested node */
3603 pte_unmap_unlock(pte, ptl);
3604 migrated = migrate_misplaced_page(page, target_nid);
3606 curr_nid = target_nid;
3607 task_numa_fault(curr_nid, 1, migrated);
3609 pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
3611 pte_unmap_unlock(orig_pte, ptl);
3616 static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3617 unsigned long addr, pmd_t *pmdp)
3622 #endif /* CONFIG_NUMA_BALANCING */
3625 * These routines also need to handle stuff like marking pages dirty
3626 * and/or accessed for architectures that don't do it in hardware (most
3627 * RISC architectures). The early dirtying is also good on the i386.
3629 * There is also a hook called "update_mmu_cache()" that architectures
3630 * with external mmu caches can use to update those (ie the Sparc or
3631 * PowerPC hashed page tables that act as extended TLBs).
3633 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3634 * but allow concurrent faults), and pte mapped but not yet locked.
3635 * We return with mmap_sem still held, but pte unmapped and unlocked.
3637 int handle_pte_fault(struct mm_struct *mm,
3638 struct vm_area_struct *vma, unsigned long address,
3639 pte_t *pte, pmd_t *pmd, unsigned int flags)
3645 if (!pte_present(entry)) {
3646 if (pte_none(entry)) {
3648 if (likely(vma->vm_ops->fault))
3649 return do_linear_fault(mm, vma, address,
3650 pte, pmd, flags, entry);
3652 return do_anonymous_page(mm, vma, address,
3655 if (pte_file(entry))
3656 return do_nonlinear_fault(mm, vma, address,
3657 pte, pmd, flags, entry);
3658 return do_swap_page(mm, vma, address,
3659 pte, pmd, flags, entry);
3662 if (pte_numa(entry))
3663 return do_numa_page(mm, vma, address, entry, pte, pmd);
3665 ptl = pte_lockptr(mm, pmd);
3667 if (unlikely(!pte_same(*pte, entry)))
3669 if (flags & FAULT_FLAG_WRITE) {
3670 if (!pte_write(entry))
3671 return do_wp_page(mm, vma, address,
3672 pte, pmd, ptl, entry);
3673 entry = pte_mkdirty(entry);
3675 entry = pte_mkyoung(entry);
3676 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3677 update_mmu_cache(vma, address, pte);
3680 * This is needed only for protection faults but the arch code
3681 * is not yet telling us if this is a protection fault or not.
3682 * This still avoids useless tlb flushes for .text page faults
3685 if (flags & FAULT_FLAG_WRITE)
3686 flush_tlb_fix_spurious_fault(vma, address);
3689 pte_unmap_unlock(pte, ptl);
3694 * By the time we get here, we already hold the mm semaphore
3696 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3697 unsigned long address, unsigned int flags)
3704 __set_current_state(TASK_RUNNING);
3706 count_vm_event(PGFAULT);
3707 mem_cgroup_count_vm_event(mm, PGFAULT);
3709 /* do counter updates before entering really critical section. */
3710 check_sync_rss_stat(current);
3712 if (unlikely(is_vm_hugetlb_page(vma)))
3713 return hugetlb_fault(mm, vma, address, flags);
3716 pgd = pgd_offset(mm, address);
3717 pud = pud_alloc(mm, pgd, address);
3719 return VM_FAULT_OOM;
3720 pmd = pmd_alloc(mm, pud, address);
3722 return VM_FAULT_OOM;
3723 if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
3725 return do_huge_pmd_anonymous_page(mm, vma, address,
3728 pmd_t orig_pmd = *pmd;
3732 if (pmd_trans_huge(orig_pmd)) {
3733 unsigned int dirty = flags & FAULT_FLAG_WRITE;
3736 * If the pmd is splitting, return and retry the
3737 * the fault. Alternative: wait until the split
3738 * is done, and goto retry.
3740 if (pmd_trans_splitting(orig_pmd))
3743 if (pmd_numa(orig_pmd))
3744 return do_huge_pmd_numa_page(mm, vma, address,
3747 if (dirty && !pmd_write(orig_pmd)) {
3748 ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
3751 * If COW results in an oom, the huge pmd will
3752 * have been split, so retry the fault on the
3753 * pte for a smaller charge.
3755 if (unlikely(ret & VM_FAULT_OOM))
3759 huge_pmd_set_accessed(mm, vma, address, pmd,
3768 return do_pmd_numa_page(mm, vma, address, pmd);
3771 * Use __pte_alloc instead of pte_alloc_map, because we can't
3772 * run pte_offset_map on the pmd, if an huge pmd could
3773 * materialize from under us from a different thread.
3775 if (unlikely(pmd_none(*pmd)) &&
3776 unlikely(__pte_alloc(mm, vma, pmd, address)))
3777 return VM_FAULT_OOM;
3778 /* if an huge pmd materialized from under us just retry later */
3779 if (unlikely(pmd_trans_huge(*pmd)))
3782 * A regular pmd is established and it can't morph into a huge pmd
3783 * from under us anymore at this point because we hold the mmap_sem
3784 * read mode and khugepaged takes it in write mode. So now it's
3785 * safe to run pte_offset_map().
3787 pte = pte_offset_map(pmd, address);
3789 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3792 #ifndef __PAGETABLE_PUD_FOLDED
3794 * Allocate page upper directory.
3795 * We've already handled the fast-path in-line.
3797 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3799 pud_t *new = pud_alloc_one(mm, address);
3803 smp_wmb(); /* See comment in __pte_alloc */
3805 spin_lock(&mm->page_table_lock);
3806 if (pgd_present(*pgd)) /* Another has populated it */
3809 pgd_populate(mm, pgd, new);
3810 spin_unlock(&mm->page_table_lock);
3813 #endif /* __PAGETABLE_PUD_FOLDED */
3815 #ifndef __PAGETABLE_PMD_FOLDED
3817 * Allocate page middle directory.
3818 * We've already handled the fast-path in-line.
3820 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3822 pmd_t *new = pmd_alloc_one(mm, address);
3826 smp_wmb(); /* See comment in __pte_alloc */
3828 spin_lock(&mm->page_table_lock);
3829 #ifndef __ARCH_HAS_4LEVEL_HACK
3830 if (pud_present(*pud)) /* Another has populated it */
3833 pud_populate(mm, pud, new);
3835 if (pgd_present(*pud)) /* Another has populated it */
3838 pgd_populate(mm, pud, new);
3839 #endif /* __ARCH_HAS_4LEVEL_HACK */
3840 spin_unlock(&mm->page_table_lock);
3843 #endif /* __PAGETABLE_PMD_FOLDED */
3845 #if !defined(__HAVE_ARCH_GATE_AREA)
3847 #if defined(AT_SYSINFO_EHDR)
3848 static struct vm_area_struct gate_vma;
3850 static int __init gate_vma_init(void)
3852 gate_vma.vm_mm = NULL;
3853 gate_vma.vm_start = FIXADDR_USER_START;
3854 gate_vma.vm_end = FIXADDR_USER_END;
3855 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3856 gate_vma.vm_page_prot = __P101;
3860 __initcall(gate_vma_init);
3863 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
3865 #ifdef AT_SYSINFO_EHDR
3872 int in_gate_area_no_mm(unsigned long addr)
3874 #ifdef AT_SYSINFO_EHDR
3875 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3881 #endif /* __HAVE_ARCH_GATE_AREA */
3883 static int __follow_pte(struct mm_struct *mm, unsigned long address,
3884 pte_t **ptepp, spinlock_t **ptlp)
3891 pgd = pgd_offset(mm, address);
3892 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3895 pud = pud_offset(pgd, address);
3896 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3899 pmd = pmd_offset(pud, address);
3900 VM_BUG_ON(pmd_trans_huge(*pmd));
3901 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3904 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3908 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3911 if (!pte_present(*ptep))
3916 pte_unmap_unlock(ptep, *ptlp);
3921 static inline int follow_pte(struct mm_struct *mm, unsigned long address,
3922 pte_t **ptepp, spinlock_t **ptlp)
3926 /* (void) is needed to make gcc happy */
3927 (void) __cond_lock(*ptlp,
3928 !(res = __follow_pte(mm, address, ptepp, ptlp)));
3933 * follow_pfn - look up PFN at a user virtual address
3934 * @vma: memory mapping
3935 * @address: user virtual address
3936 * @pfn: location to store found PFN
3938 * Only IO mappings and raw PFN mappings are allowed.
3940 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3942 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3949 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3952 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3955 *pfn = pte_pfn(*ptep);
3956 pte_unmap_unlock(ptep, ptl);
3959 EXPORT_SYMBOL(follow_pfn);
3961 #ifdef CONFIG_HAVE_IOREMAP_PROT
3962 int follow_phys(struct vm_area_struct *vma,
3963 unsigned long address, unsigned int flags,
3964 unsigned long *prot, resource_size_t *phys)
3970 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3973 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
3977 if ((flags & FOLL_WRITE) && !pte_write(pte))
3980 *prot = pgprot_val(pte_pgprot(pte));
3981 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
3985 pte_unmap_unlock(ptep, ptl);
3990 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3991 void *buf, int len, int write)
3993 resource_size_t phys_addr;
3994 unsigned long prot = 0;
3995 void __iomem *maddr;
3996 int offset = addr & (PAGE_SIZE-1);
3998 if (follow_phys(vma, addr, write, &prot, &phys_addr))
4001 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
4003 memcpy_toio(maddr + offset, buf, len);
4005 memcpy_fromio(buf, maddr + offset, len);
4013 * Access another process' address space as given in mm. If non-NULL, use the
4014 * given task for page fault accounting.
4016 static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
4017 unsigned long addr, void *buf, int len, int write)
4019 struct vm_area_struct *vma;
4020 void *old_buf = buf;
4022 down_read(&mm->mmap_sem);
4023 /* ignore errors, just check how much was successfully transferred */
4025 int bytes, ret, offset;
4027 struct page *page = NULL;
4029 ret = get_user_pages(tsk, mm, addr, 1,
4030 write, 1, &page, &vma);
4033 * Check if this is a VM_IO | VM_PFNMAP VMA, which
4034 * we can access using slightly different code.
4036 #ifdef CONFIG_HAVE_IOREMAP_PROT
4037 vma = find_vma(mm, addr);
4038 if (!vma || vma->vm_start > addr)
4040 if (vma->vm_ops && vma->vm_ops->access)
4041 ret = vma->vm_ops->access(vma, addr, buf,
4049 offset = addr & (PAGE_SIZE-1);
4050 if (bytes > PAGE_SIZE-offset)
4051 bytes = PAGE_SIZE-offset;
4055 copy_to_user_page(vma, page, addr,
4056 maddr + offset, buf, bytes);
4057 set_page_dirty_lock(page);
4059 copy_from_user_page(vma, page, addr,
4060 buf, maddr + offset, bytes);
4063 page_cache_release(page);
4069 up_read(&mm->mmap_sem);
4071 return buf - old_buf;
4075 * access_remote_vm - access another process' address space
4076 * @mm: the mm_struct of the target address space
4077 * @addr: start address to access
4078 * @buf: source or destination buffer
4079 * @len: number of bytes to transfer
4080 * @write: whether the access is a write
4082 * The caller must hold a reference on @mm.
4084 int access_remote_vm(struct mm_struct *mm, unsigned long addr,
4085 void *buf, int len, int write)
4087 return __access_remote_vm(NULL, mm, addr, buf, len, write);
4091 * Access another process' address space.
4092 * Source/target buffer must be kernel space,
4093 * Do not walk the page table directly, use get_user_pages
4095 int access_process_vm(struct task_struct *tsk, unsigned long addr,
4096 void *buf, int len, int write)
4098 struct mm_struct *mm;
4101 mm = get_task_mm(tsk);
4105 ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
4112 * Print the name of a VMA.
4114 void print_vma_addr(char *prefix, unsigned long ip)
4116 struct mm_struct *mm = current->mm;
4117 struct vm_area_struct *vma;
4120 * Do not print if we are in atomic
4121 * contexts (in exception stacks, etc.):
4123 if (preempt_count())
4126 down_read(&mm->mmap_sem);
4127 vma = find_vma(mm, ip);
4128 if (vma && vma->vm_file) {
4129 struct file *f = vma->vm_file;
4130 char *buf = (char *)__get_free_page(GFP_KERNEL);
4134 p = d_path(&f->f_path, buf, PAGE_SIZE);
4137 printk("%s%s[%lx+%lx]", prefix, kbasename(p),
4139 vma->vm_end - vma->vm_start);
4140 free_page((unsigned long)buf);
4143 up_read(&mm->mmap_sem);
4146 #ifdef CONFIG_PROVE_LOCKING
4147 void might_fault(void)
4150 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4151 * holding the mmap_sem, this is safe because kernel memory doesn't
4152 * get paged out, therefore we'll never actually fault, and the
4153 * below annotations will generate false positives.
4155 if (segment_eq(get_fs(), KERNEL_DS))
4160 * it would be nicer only to annotate paths which are not under
4161 * pagefault_disable, however that requires a larger audit and
4162 * providing helpers like get_user_atomic.
4164 if (!in_atomic() && current->mm)
4165 might_lock_read(¤t->mm->mmap_sem);
4167 EXPORT_SYMBOL(might_fault);
4170 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4171 static void clear_gigantic_page(struct page *page,
4173 unsigned int pages_per_huge_page)
4176 struct page *p = page;
4179 for (i = 0; i < pages_per_huge_page;
4180 i++, p = mem_map_next(p, page, i)) {
4182 clear_user_highpage(p, addr + i * PAGE_SIZE);
4185 void clear_huge_page(struct page *page,
4186 unsigned long addr, unsigned int pages_per_huge_page)
4190 if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4191 clear_gigantic_page(page, addr, pages_per_huge_page);
4196 for (i = 0; i < pages_per_huge_page; i++) {
4198 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
4202 static void copy_user_gigantic_page(struct page *dst, struct page *src,
4204 struct vm_area_struct *vma,
4205 unsigned int pages_per_huge_page)
4208 struct page *dst_base = dst;
4209 struct page *src_base = src;
4211 for (i = 0; i < pages_per_huge_page; ) {
4213 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
4216 dst = mem_map_next(dst, dst_base, i);
4217 src = mem_map_next(src, src_base, i);
4221 void copy_user_huge_page(struct page *dst, struct page *src,
4222 unsigned long addr, struct vm_area_struct *vma,
4223 unsigned int pages_per_huge_page)
4227 if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4228 copy_user_gigantic_page(dst, src, addr, vma,
4229 pages_per_huge_page);
4234 for (i = 0; i < pages_per_huge_page; i++) {
4236 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
4239 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */