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;
219 tlb->need_flush_all = 0;
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 for (batch = &tlb->local; batch; batch = batch->next) {
247 free_pages_and_swap_cache(batch->pages, batch->nr);
250 tlb->active = &tlb->local;
254 * Called at the end of the shootdown operation to free up any resources
255 * that were required.
257 void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
259 struct mmu_gather_batch *batch, *next;
265 /* keep the page table cache within bounds */
268 for (batch = tlb->local.next; batch; batch = next) {
270 free_pages((unsigned long)batch, 0);
272 tlb->local.next = NULL;
276 * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
277 * handling the additional races in SMP caused by other CPUs caching valid
278 * mappings in their TLBs. Returns the number of free page slots left.
279 * When out of page slots we must call tlb_flush_mmu().
281 int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
283 struct mmu_gather_batch *batch;
285 VM_BUG_ON(!tlb->need_flush);
288 batch->pages[batch->nr++] = page;
289 if (batch->nr == batch->max) {
290 if (!tlb_next_batch(tlb))
294 VM_BUG_ON(batch->nr > batch->max);
296 return batch->max - batch->nr;
299 #endif /* HAVE_GENERIC_MMU_GATHER */
301 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
304 * See the comment near struct mmu_table_batch.
307 static void tlb_remove_table_smp_sync(void *arg)
309 /* Simply deliver the interrupt */
312 static void tlb_remove_table_one(void *table)
315 * This isn't an RCU grace period and hence the page-tables cannot be
316 * assumed to be actually RCU-freed.
318 * It is however sufficient for software page-table walkers that rely on
319 * IRQ disabling. See the comment near struct mmu_table_batch.
321 smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
322 __tlb_remove_table(table);
325 static void tlb_remove_table_rcu(struct rcu_head *head)
327 struct mmu_table_batch *batch;
330 batch = container_of(head, struct mmu_table_batch, rcu);
332 for (i = 0; i < batch->nr; i++)
333 __tlb_remove_table(batch->tables[i]);
335 free_page((unsigned long)batch);
338 void tlb_table_flush(struct mmu_gather *tlb)
340 struct mmu_table_batch **batch = &tlb->batch;
343 call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
348 void tlb_remove_table(struct mmu_gather *tlb, void *table)
350 struct mmu_table_batch **batch = &tlb->batch;
355 * When there's less then two users of this mm there cannot be a
356 * concurrent page-table walk.
358 if (atomic_read(&tlb->mm->mm_users) < 2) {
359 __tlb_remove_table(table);
363 if (*batch == NULL) {
364 *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
365 if (*batch == NULL) {
366 tlb_remove_table_one(table);
371 (*batch)->tables[(*batch)->nr++] = table;
372 if ((*batch)->nr == MAX_TABLE_BATCH)
373 tlb_table_flush(tlb);
376 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
379 * If a p?d_bad entry is found while walking page tables, report
380 * the error, before resetting entry to p?d_none. Usually (but
381 * very seldom) called out from the p?d_none_or_clear_bad macros.
384 void pgd_clear_bad(pgd_t *pgd)
390 void pud_clear_bad(pud_t *pud)
396 void pmd_clear_bad(pmd_t *pmd)
403 * Note: this doesn't free the actual pages themselves. That
404 * has been handled earlier when unmapping all the memory regions.
406 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
409 pgtable_t token = pmd_pgtable(*pmd);
411 pte_free_tlb(tlb, token, addr);
415 static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
416 unsigned long addr, unsigned long end,
417 unsigned long floor, unsigned long ceiling)
424 pmd = pmd_offset(pud, addr);
426 next = pmd_addr_end(addr, end);
427 if (pmd_none_or_clear_bad(pmd))
429 free_pte_range(tlb, pmd, addr);
430 } while (pmd++, addr = next, addr != end);
440 if (end - 1 > ceiling - 1)
443 pmd = pmd_offset(pud, start);
445 pmd_free_tlb(tlb, pmd, start);
448 static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
449 unsigned long addr, unsigned long end,
450 unsigned long floor, unsigned long ceiling)
457 pud = pud_offset(pgd, addr);
459 next = pud_addr_end(addr, end);
460 if (pud_none_or_clear_bad(pud))
462 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
463 } while (pud++, addr = next, addr != end);
469 ceiling &= PGDIR_MASK;
473 if (end - 1 > ceiling - 1)
476 pud = pud_offset(pgd, start);
478 pud_free_tlb(tlb, pud, start);
482 * This function frees user-level page tables of a process.
484 * Must be called with pagetable lock held.
486 void free_pgd_range(struct mmu_gather *tlb,
487 unsigned long addr, unsigned long end,
488 unsigned long floor, unsigned long ceiling)
494 * The next few lines have given us lots of grief...
496 * Why are we testing PMD* at this top level? Because often
497 * there will be no work to do at all, and we'd prefer not to
498 * go all the way down to the bottom just to discover that.
500 * Why all these "- 1"s? Because 0 represents both the bottom
501 * of the address space and the top of it (using -1 for the
502 * top wouldn't help much: the masks would do the wrong thing).
503 * The rule is that addr 0 and floor 0 refer to the bottom of
504 * the address space, but end 0 and ceiling 0 refer to the top
505 * Comparisons need to use "end - 1" and "ceiling - 1" (though
506 * that end 0 case should be mythical).
508 * Wherever addr is brought up or ceiling brought down, we must
509 * be careful to reject "the opposite 0" before it confuses the
510 * subsequent tests. But what about where end is brought down
511 * by PMD_SIZE below? no, end can't go down to 0 there.
513 * Whereas we round start (addr) and ceiling down, by different
514 * masks at different levels, in order to test whether a table
515 * now has no other vmas using it, so can be freed, we don't
516 * bother to round floor or end up - the tests don't need that.
530 if (end - 1 > ceiling - 1)
535 pgd = pgd_offset(tlb->mm, addr);
537 next = pgd_addr_end(addr, end);
538 if (pgd_none_or_clear_bad(pgd))
540 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
541 } while (pgd++, addr = next, addr != end);
544 void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
545 unsigned long floor, unsigned long ceiling)
548 struct vm_area_struct *next = vma->vm_next;
549 unsigned long addr = vma->vm_start;
552 * Hide vma from rmap and truncate_pagecache before freeing
555 unlink_anon_vmas(vma);
556 unlink_file_vma(vma);
558 if (is_vm_hugetlb_page(vma)) {
559 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
560 floor, next? next->vm_start: ceiling);
563 * Optimization: gather nearby vmas into one call down
565 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
566 && !is_vm_hugetlb_page(next)) {
569 unlink_anon_vmas(vma);
570 unlink_file_vma(vma);
572 free_pgd_range(tlb, addr, vma->vm_end,
573 floor, next? next->vm_start: ceiling);
579 int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
580 pmd_t *pmd, unsigned long address)
582 pgtable_t new = pte_alloc_one(mm, address);
583 int wait_split_huge_page;
588 * Ensure all pte setup (eg. pte page lock and page clearing) are
589 * visible before the pte is made visible to other CPUs by being
590 * put into page tables.
592 * The other side of the story is the pointer chasing in the page
593 * table walking code (when walking the page table without locking;
594 * ie. most of the time). Fortunately, these data accesses consist
595 * of a chain of data-dependent loads, meaning most CPUs (alpha
596 * being the notable exception) will already guarantee loads are
597 * seen in-order. See the alpha page table accessors for the
598 * smp_read_barrier_depends() barriers in page table walking code.
600 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
602 spin_lock(&mm->page_table_lock);
603 wait_split_huge_page = 0;
604 if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
606 pmd_populate(mm, pmd, new);
608 } else if (unlikely(pmd_trans_splitting(*pmd)))
609 wait_split_huge_page = 1;
610 spin_unlock(&mm->page_table_lock);
613 if (wait_split_huge_page)
614 wait_split_huge_page(vma->anon_vma, pmd);
618 int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
620 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
624 smp_wmb(); /* See comment in __pte_alloc */
626 spin_lock(&init_mm.page_table_lock);
627 if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
628 pmd_populate_kernel(&init_mm, pmd, new);
631 VM_BUG_ON(pmd_trans_splitting(*pmd));
632 spin_unlock(&init_mm.page_table_lock);
634 pte_free_kernel(&init_mm, new);
638 static inline void init_rss_vec(int *rss)
640 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
643 static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
647 if (current->mm == mm)
649 for (i = 0; i < NR_MM_COUNTERS; i++)
651 add_mm_counter(mm, i, rss[i]);
655 * This function is called to print an error when a bad pte
656 * is found. For example, we might have a PFN-mapped pte in
657 * a region that doesn't allow it.
659 * The calling function must still handle the error.
661 static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
662 pte_t pte, struct page *page)
664 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
665 pud_t *pud = pud_offset(pgd, addr);
666 pmd_t *pmd = pmd_offset(pud, addr);
667 struct address_space *mapping;
669 static unsigned long resume;
670 static unsigned long nr_shown;
671 static unsigned long nr_unshown;
674 * Allow a burst of 60 reports, then keep quiet for that minute;
675 * or allow a steady drip of one report per second.
677 if (nr_shown == 60) {
678 if (time_before(jiffies, resume)) {
684 "BUG: Bad page map: %lu messages suppressed\n",
691 resume = jiffies + 60 * HZ;
693 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
694 index = linear_page_index(vma, addr);
697 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
699 (long long)pte_val(pte), (long long)pmd_val(*pmd));
703 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
704 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
706 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
709 printk(KERN_ALERT "vma->vm_ops->fault: %pSR\n",
711 if (vma->vm_file && vma->vm_file->f_op)
712 printk(KERN_ALERT "vma->vm_file->f_op->mmap: %pSR\n",
713 vma->vm_file->f_op->mmap);
715 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
718 static inline bool is_cow_mapping(vm_flags_t flags)
720 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
724 * vm_normal_page -- This function gets the "struct page" associated with a pte.
726 * "Special" mappings do not wish to be associated with a "struct page" (either
727 * it doesn't exist, or it exists but they don't want to touch it). In this
728 * case, NULL is returned here. "Normal" mappings do have a struct page.
730 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
731 * pte bit, in which case this function is trivial. Secondly, an architecture
732 * may not have a spare pte bit, which requires a more complicated scheme,
735 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
736 * special mapping (even if there are underlying and valid "struct pages").
737 * COWed pages of a VM_PFNMAP are always normal.
739 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
740 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
741 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
742 * mapping will always honor the rule
744 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
746 * And for normal mappings this is false.
748 * This restricts such mappings to be a linear translation from virtual address
749 * to pfn. To get around this restriction, we allow arbitrary mappings so long
750 * as the vma is not a COW mapping; in that case, we know that all ptes are
751 * special (because none can have been COWed).
754 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
756 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
757 * page" backing, however the difference is that _all_ pages with a struct
758 * page (that is, those where pfn_valid is true) are refcounted and considered
759 * normal pages by the VM. The disadvantage is that pages are refcounted
760 * (which can be slower and simply not an option for some PFNMAP users). The
761 * advantage is that we don't have to follow the strict linearity rule of
762 * PFNMAP mappings in order to support COWable mappings.
765 #ifdef __HAVE_ARCH_PTE_SPECIAL
766 # define HAVE_PTE_SPECIAL 1
768 # define HAVE_PTE_SPECIAL 0
770 struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
773 unsigned long pfn = pte_pfn(pte);
775 if (HAVE_PTE_SPECIAL) {
776 if (likely(!pte_special(pte)))
778 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
780 if (!is_zero_pfn(pfn))
781 print_bad_pte(vma, addr, pte, NULL);
785 /* !HAVE_PTE_SPECIAL case follows: */
787 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
788 if (vma->vm_flags & VM_MIXEDMAP) {
794 off = (addr - vma->vm_start) >> PAGE_SHIFT;
795 if (pfn == vma->vm_pgoff + off)
797 if (!is_cow_mapping(vma->vm_flags))
802 if (is_zero_pfn(pfn))
805 if (unlikely(pfn > highest_memmap_pfn)) {
806 print_bad_pte(vma, addr, pte, NULL);
811 * NOTE! We still have PageReserved() pages in the page tables.
812 * eg. VDSO mappings can cause them to exist.
815 return pfn_to_page(pfn);
819 * copy one vm_area from one task to the other. Assumes the page tables
820 * already present in the new task to be cleared in the whole range
821 * covered by this vma.
824 static inline unsigned long
825 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
826 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
827 unsigned long addr, int *rss)
829 unsigned long vm_flags = vma->vm_flags;
830 pte_t pte = *src_pte;
833 /* pte contains position in swap or file, so copy. */
834 if (unlikely(!pte_present(pte))) {
835 if (!pte_file(pte)) {
836 swp_entry_t entry = pte_to_swp_entry(pte);
838 if (swap_duplicate(entry) < 0)
841 /* make sure dst_mm is on swapoff's mmlist. */
842 if (unlikely(list_empty(&dst_mm->mmlist))) {
843 spin_lock(&mmlist_lock);
844 if (list_empty(&dst_mm->mmlist))
845 list_add(&dst_mm->mmlist,
847 spin_unlock(&mmlist_lock);
849 if (likely(!non_swap_entry(entry)))
851 else if (is_migration_entry(entry)) {
852 page = migration_entry_to_page(entry);
859 if (is_write_migration_entry(entry) &&
860 is_cow_mapping(vm_flags)) {
862 * COW mappings require pages in both
863 * parent and child to be set to read.
865 make_migration_entry_read(&entry);
866 pte = swp_entry_to_pte(entry);
867 set_pte_at(src_mm, addr, src_pte, pte);
875 * If it's a COW mapping, write protect it both
876 * in the parent and the child
878 if (is_cow_mapping(vm_flags)) {
879 ptep_set_wrprotect(src_mm, addr, src_pte);
880 pte = pte_wrprotect(pte);
884 * If it's a shared mapping, mark it clean in
887 if (vm_flags & VM_SHARED)
888 pte = pte_mkclean(pte);
889 pte = pte_mkold(pte);
891 page = vm_normal_page(vma, addr, pte);
902 set_pte_at(dst_mm, addr, dst_pte, pte);
906 int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
907 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
908 unsigned long addr, unsigned long end)
910 pte_t *orig_src_pte, *orig_dst_pte;
911 pte_t *src_pte, *dst_pte;
912 spinlock_t *src_ptl, *dst_ptl;
914 int rss[NR_MM_COUNTERS];
915 swp_entry_t entry = (swp_entry_t){0};
920 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
923 src_pte = pte_offset_map(src_pmd, addr);
924 src_ptl = pte_lockptr(src_mm, src_pmd);
925 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
926 orig_src_pte = src_pte;
927 orig_dst_pte = dst_pte;
928 arch_enter_lazy_mmu_mode();
932 * We are holding two locks at this point - either of them
933 * could generate latencies in another task on another CPU.
935 if (progress >= 32) {
937 if (need_resched() ||
938 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
941 if (pte_none(*src_pte)) {
945 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
950 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
952 arch_leave_lazy_mmu_mode();
953 spin_unlock(src_ptl);
954 pte_unmap(orig_src_pte);
955 add_mm_rss_vec(dst_mm, rss);
956 pte_unmap_unlock(orig_dst_pte, dst_ptl);
960 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
969 static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
970 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
971 unsigned long addr, unsigned long end)
973 pmd_t *src_pmd, *dst_pmd;
976 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
979 src_pmd = pmd_offset(src_pud, addr);
981 next = pmd_addr_end(addr, end);
982 if (pmd_trans_huge(*src_pmd)) {
984 VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
985 err = copy_huge_pmd(dst_mm, src_mm,
986 dst_pmd, src_pmd, addr, vma);
993 if (pmd_none_or_clear_bad(src_pmd))
995 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
998 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
1002 static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1003 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
1004 unsigned long addr, unsigned long end)
1006 pud_t *src_pud, *dst_pud;
1009 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
1012 src_pud = pud_offset(src_pgd, addr);
1014 next = pud_addr_end(addr, end);
1015 if (pud_none_or_clear_bad(src_pud))
1017 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
1020 } while (dst_pud++, src_pud++, addr = next, addr != end);
1024 int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
1025 struct vm_area_struct *vma)
1027 pgd_t *src_pgd, *dst_pgd;
1029 unsigned long addr = vma->vm_start;
1030 unsigned long end = vma->vm_end;
1031 unsigned long mmun_start; /* For mmu_notifiers */
1032 unsigned long mmun_end; /* For mmu_notifiers */
1037 * Don't copy ptes where a page fault will fill them correctly.
1038 * Fork becomes much lighter when there are big shared or private
1039 * readonly mappings. The tradeoff is that copy_page_range is more
1040 * efficient than faulting.
1042 if (!(vma->vm_flags & (VM_HUGETLB | VM_NONLINEAR |
1043 VM_PFNMAP | VM_MIXEDMAP))) {
1048 if (is_vm_hugetlb_page(vma))
1049 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
1051 if (unlikely(vma->vm_flags & VM_PFNMAP)) {
1053 * We do not free on error cases below as remove_vma
1054 * gets called on error from higher level routine
1056 ret = track_pfn_copy(vma);
1062 * We need to invalidate the secondary MMU mappings only when
1063 * there could be a permission downgrade on the ptes of the
1064 * parent mm. And a permission downgrade will only happen if
1065 * is_cow_mapping() returns true.
1067 is_cow = is_cow_mapping(vma->vm_flags);
1071 mmu_notifier_invalidate_range_start(src_mm, mmun_start,
1075 dst_pgd = pgd_offset(dst_mm, addr);
1076 src_pgd = pgd_offset(src_mm, addr);
1078 next = pgd_addr_end(addr, end);
1079 if (pgd_none_or_clear_bad(src_pgd))
1081 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
1082 vma, addr, next))) {
1086 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
1089 mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end);
1093 static unsigned long zap_pte_range(struct mmu_gather *tlb,
1094 struct vm_area_struct *vma, pmd_t *pmd,
1095 unsigned long addr, unsigned long end,
1096 struct zap_details *details)
1098 struct mm_struct *mm = tlb->mm;
1099 int force_flush = 0;
1100 int rss[NR_MM_COUNTERS];
1104 unsigned long range_start = addr;
1108 start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
1110 arch_enter_lazy_mmu_mode();
1113 if (pte_none(ptent)) {
1117 if (pte_present(ptent)) {
1120 page = vm_normal_page(vma, addr, ptent);
1121 if (unlikely(details) && page) {
1123 * unmap_shared_mapping_pages() wants to
1124 * invalidate cache without truncating:
1125 * unmap shared but keep private pages.
1127 if (details->check_mapping &&
1128 details->check_mapping != page->mapping)
1131 * Each page->index must be checked when
1132 * invalidating or truncating nonlinear.
1134 if (details->nonlinear_vma &&
1135 (page->index < details->first_index ||
1136 page->index > details->last_index))
1139 ptent = ptep_get_and_clear_full(mm, addr, pte,
1141 tlb_remove_tlb_entry(tlb, pte, addr);
1142 if (unlikely(!page))
1144 if (unlikely(details) && details->nonlinear_vma
1145 && linear_page_index(details->nonlinear_vma,
1146 addr) != page->index)
1147 set_pte_at(mm, addr, pte,
1148 pgoff_to_pte(page->index));
1150 rss[MM_ANONPAGES]--;
1152 if (pte_dirty(ptent))
1153 set_page_dirty(page);
1154 if (pte_young(ptent) &&
1155 likely(!VM_SequentialReadHint(vma)))
1156 mark_page_accessed(page);
1157 rss[MM_FILEPAGES]--;
1159 page_remove_rmap(page);
1160 if (unlikely(page_mapcount(page) < 0))
1161 print_bad_pte(vma, addr, ptent, page);
1162 force_flush = !__tlb_remove_page(tlb, page);
1168 * If details->check_mapping, we leave swap entries;
1169 * if details->nonlinear_vma, we leave file entries.
1171 if (unlikely(details))
1173 if (pte_file(ptent)) {
1174 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
1175 print_bad_pte(vma, addr, ptent, NULL);
1177 swp_entry_t entry = pte_to_swp_entry(ptent);
1179 if (!non_swap_entry(entry))
1181 else if (is_migration_entry(entry)) {
1184 page = migration_entry_to_page(entry);
1187 rss[MM_ANONPAGES]--;
1189 rss[MM_FILEPAGES]--;
1191 if (unlikely(!free_swap_and_cache(entry)))
1192 print_bad_pte(vma, addr, ptent, NULL);
1194 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
1195 } while (pte++, addr += PAGE_SIZE, addr != end);
1197 add_mm_rss_vec(mm, rss);
1198 arch_leave_lazy_mmu_mode();
1199 pte_unmap_unlock(start_pte, ptl);
1202 * mmu_gather ran out of room to batch pages, we break out of
1203 * the PTE lock to avoid doing the potential expensive TLB invalidate
1204 * and page-free while holding it.
1209 #ifdef HAVE_GENERIC_MMU_GATHER
1210 tlb->start = range_start;
1223 static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
1224 struct vm_area_struct *vma, pud_t *pud,
1225 unsigned long addr, unsigned long end,
1226 struct zap_details *details)
1231 pmd = pmd_offset(pud, addr);
1233 next = pmd_addr_end(addr, end);
1234 if (pmd_trans_huge(*pmd)) {
1235 if (next - addr != HPAGE_PMD_SIZE) {
1236 #ifdef CONFIG_DEBUG_VM
1237 if (!rwsem_is_locked(&tlb->mm->mmap_sem)) {
1238 pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n",
1239 __func__, addr, end,
1245 split_huge_page_pmd(vma, addr, pmd);
1246 } else if (zap_huge_pmd(tlb, vma, pmd, addr))
1251 * Here there can be other concurrent MADV_DONTNEED or
1252 * trans huge page faults running, and if the pmd is
1253 * none or trans huge it can change under us. This is
1254 * because MADV_DONTNEED holds the mmap_sem in read
1257 if (pmd_none_or_trans_huge_or_clear_bad(pmd))
1259 next = zap_pte_range(tlb, vma, pmd, addr, next, details);
1262 } while (pmd++, addr = next, addr != end);
1267 static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1268 struct vm_area_struct *vma, pgd_t *pgd,
1269 unsigned long addr, unsigned long end,
1270 struct zap_details *details)
1275 pud = pud_offset(pgd, addr);
1277 next = pud_addr_end(addr, end);
1278 if (pud_none_or_clear_bad(pud))
1280 next = zap_pmd_range(tlb, vma, pud, addr, next, details);
1281 } while (pud++, addr = next, addr != end);
1286 static void unmap_page_range(struct mmu_gather *tlb,
1287 struct vm_area_struct *vma,
1288 unsigned long addr, unsigned long end,
1289 struct zap_details *details)
1294 if (details && !details->check_mapping && !details->nonlinear_vma)
1297 BUG_ON(addr >= end);
1298 mem_cgroup_uncharge_start();
1299 tlb_start_vma(tlb, vma);
1300 pgd = pgd_offset(vma->vm_mm, addr);
1302 next = pgd_addr_end(addr, end);
1303 if (pgd_none_or_clear_bad(pgd))
1305 next = zap_pud_range(tlb, vma, pgd, addr, next, details);
1306 } while (pgd++, addr = next, addr != end);
1307 tlb_end_vma(tlb, vma);
1308 mem_cgroup_uncharge_end();
1312 static void unmap_single_vma(struct mmu_gather *tlb,
1313 struct vm_area_struct *vma, unsigned long start_addr,
1314 unsigned long end_addr,
1315 struct zap_details *details)
1317 unsigned long start = max(vma->vm_start, start_addr);
1320 if (start >= vma->vm_end)
1322 end = min(vma->vm_end, end_addr);
1323 if (end <= vma->vm_start)
1327 uprobe_munmap(vma, start, end);
1329 if (unlikely(vma->vm_flags & VM_PFNMAP))
1330 untrack_pfn(vma, 0, 0);
1333 if (unlikely(is_vm_hugetlb_page(vma))) {
1335 * It is undesirable to test vma->vm_file as it
1336 * should be non-null for valid hugetlb area.
1337 * However, vm_file will be NULL in the error
1338 * cleanup path of do_mmap_pgoff. When
1339 * hugetlbfs ->mmap method fails,
1340 * do_mmap_pgoff() nullifies vma->vm_file
1341 * before calling this function to clean up.
1342 * Since no pte has actually been setup, it is
1343 * safe to do nothing in this case.
1346 mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
1347 __unmap_hugepage_range_final(tlb, vma, start, end, NULL);
1348 mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
1351 unmap_page_range(tlb, vma, start, end, details);
1356 * unmap_vmas - unmap a range of memory covered by a list of vma's
1357 * @tlb: address of the caller's struct mmu_gather
1358 * @vma: the starting vma
1359 * @start_addr: virtual address at which to start unmapping
1360 * @end_addr: virtual address at which to end unmapping
1362 * Unmap all pages in the vma list.
1364 * Only addresses between `start' and `end' will be unmapped.
1366 * The VMA list must be sorted in ascending virtual address order.
1368 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1369 * range after unmap_vmas() returns. So the only responsibility here is to
1370 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1371 * drops the lock and schedules.
1373 void unmap_vmas(struct mmu_gather *tlb,
1374 struct vm_area_struct *vma, unsigned long start_addr,
1375 unsigned long end_addr)
1377 struct mm_struct *mm = vma->vm_mm;
1379 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1380 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
1381 unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
1382 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1386 * zap_page_range - remove user pages in a given range
1387 * @vma: vm_area_struct holding the applicable pages
1388 * @start: starting address of pages to zap
1389 * @size: number of bytes to zap
1390 * @details: details of nonlinear truncation or shared cache invalidation
1392 * Caller must protect the VMA list
1394 void zap_page_range(struct vm_area_struct *vma, unsigned long start,
1395 unsigned long size, struct zap_details *details)
1397 struct mm_struct *mm = vma->vm_mm;
1398 struct mmu_gather tlb;
1399 unsigned long end = start + size;
1402 tlb_gather_mmu(&tlb, mm, 0);
1403 update_hiwater_rss(mm);
1404 mmu_notifier_invalidate_range_start(mm, start, end);
1405 for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
1406 unmap_single_vma(&tlb, vma, start, end, details);
1407 mmu_notifier_invalidate_range_end(mm, start, end);
1408 tlb_finish_mmu(&tlb, start, end);
1412 * zap_page_range_single - remove user pages in a given range
1413 * @vma: vm_area_struct holding the applicable pages
1414 * @address: starting address of pages to zap
1415 * @size: number of bytes to zap
1416 * @details: details of nonlinear truncation or shared cache invalidation
1418 * The range must fit into one VMA.
1420 static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
1421 unsigned long size, struct zap_details *details)
1423 struct mm_struct *mm = vma->vm_mm;
1424 struct mmu_gather tlb;
1425 unsigned long end = address + size;
1428 tlb_gather_mmu(&tlb, mm, 0);
1429 update_hiwater_rss(mm);
1430 mmu_notifier_invalidate_range_start(mm, address, end);
1431 unmap_single_vma(&tlb, vma, address, end, details);
1432 mmu_notifier_invalidate_range_end(mm, address, end);
1433 tlb_finish_mmu(&tlb, address, end);
1437 * zap_vma_ptes - remove ptes mapping the vma
1438 * @vma: vm_area_struct holding ptes to be zapped
1439 * @address: starting address of pages to zap
1440 * @size: number of bytes to zap
1442 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1444 * The entire address range must be fully contained within the vma.
1446 * Returns 0 if successful.
1448 int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1451 if (address < vma->vm_start || address + size > vma->vm_end ||
1452 !(vma->vm_flags & VM_PFNMAP))
1454 zap_page_range_single(vma, address, size, NULL);
1457 EXPORT_SYMBOL_GPL(zap_vma_ptes);
1460 * follow_page_mask - look up a page descriptor from a user-virtual address
1461 * @vma: vm_area_struct mapping @address
1462 * @address: virtual address to look up
1463 * @flags: flags modifying lookup behaviour
1464 * @page_mask: on output, *page_mask is set according to the size of the page
1466 * @flags can have FOLL_ flags set, defined in <linux/mm.h>
1468 * Returns the mapped (struct page *), %NULL if no mapping exists, or
1469 * an error pointer if there is a mapping to something not represented
1470 * by a page descriptor (see also vm_normal_page()).
1472 struct page *follow_page_mask(struct vm_area_struct *vma,
1473 unsigned long address, unsigned int flags,
1474 unsigned int *page_mask)
1482 struct mm_struct *mm = vma->vm_mm;
1486 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1487 if (!IS_ERR(page)) {
1488 BUG_ON(flags & FOLL_GET);
1493 pgd = pgd_offset(mm, address);
1494 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1497 pud = pud_offset(pgd, address);
1500 if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
1501 BUG_ON(flags & FOLL_GET);
1502 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1505 if (unlikely(pud_bad(*pud)))
1508 pmd = pmd_offset(pud, address);
1511 if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) {
1512 BUG_ON(flags & FOLL_GET);
1513 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1516 if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
1518 if (pmd_trans_huge(*pmd)) {
1519 if (flags & FOLL_SPLIT) {
1520 split_huge_page_pmd(vma, address, pmd);
1521 goto split_fallthrough;
1523 spin_lock(&mm->page_table_lock);
1524 if (likely(pmd_trans_huge(*pmd))) {
1525 if (unlikely(pmd_trans_splitting(*pmd))) {
1526 spin_unlock(&mm->page_table_lock);
1527 wait_split_huge_page(vma->anon_vma, pmd);
1529 page = follow_trans_huge_pmd(vma, address,
1531 spin_unlock(&mm->page_table_lock);
1532 *page_mask = HPAGE_PMD_NR - 1;
1536 spin_unlock(&mm->page_table_lock);
1540 if (unlikely(pmd_bad(*pmd)))
1543 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1546 if (!pte_present(pte)) {
1549 * KSM's break_ksm() relies upon recognizing a ksm page
1550 * even while it is being migrated, so for that case we
1551 * need migration_entry_wait().
1553 if (likely(!(flags & FOLL_MIGRATION)))
1555 if (pte_none(pte) || pte_file(pte))
1557 entry = pte_to_swp_entry(pte);
1558 if (!is_migration_entry(entry))
1560 pte_unmap_unlock(ptep, ptl);
1561 migration_entry_wait(mm, pmd, address);
1562 goto split_fallthrough;
1564 if ((flags & FOLL_NUMA) && pte_numa(pte))
1566 if ((flags & FOLL_WRITE) && !pte_write(pte))
1569 page = vm_normal_page(vma, address, pte);
1570 if (unlikely(!page)) {
1571 if ((flags & FOLL_DUMP) ||
1572 !is_zero_pfn(pte_pfn(pte)))
1574 page = pte_page(pte);
1577 if (flags & FOLL_GET)
1578 get_page_foll(page);
1579 if (flags & FOLL_TOUCH) {
1580 if ((flags & FOLL_WRITE) &&
1581 !pte_dirty(pte) && !PageDirty(page))
1582 set_page_dirty(page);
1584 * pte_mkyoung() would be more correct here, but atomic care
1585 * is needed to avoid losing the dirty bit: it is easier to use
1586 * mark_page_accessed().
1588 mark_page_accessed(page);
1590 if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1592 * The preliminary mapping check is mainly to avoid the
1593 * pointless overhead of lock_page on the ZERO_PAGE
1594 * which might bounce very badly if there is contention.
1596 * If the page is already locked, we don't need to
1597 * handle it now - vmscan will handle it later if and
1598 * when it attempts to reclaim the page.
1600 if (page->mapping && trylock_page(page)) {
1601 lru_add_drain(); /* push cached pages to LRU */
1603 * Because we lock page here, and migration is
1604 * blocked by the pte's page reference, and we
1605 * know the page is still mapped, we don't even
1606 * need to check for file-cache page truncation.
1608 mlock_vma_page(page);
1613 pte_unmap_unlock(ptep, ptl);
1618 pte_unmap_unlock(ptep, ptl);
1619 return ERR_PTR(-EFAULT);
1622 pte_unmap_unlock(ptep, ptl);
1628 * When core dumping an enormous anonymous area that nobody
1629 * has touched so far, we don't want to allocate unnecessary pages or
1630 * page tables. Return error instead of NULL to skip handle_mm_fault,
1631 * then get_dump_page() will return NULL to leave a hole in the dump.
1632 * But we can only make this optimization where a hole would surely
1633 * be zero-filled if handle_mm_fault() actually did handle it.
1635 if ((flags & FOLL_DUMP) &&
1636 (!vma->vm_ops || !vma->vm_ops->fault))
1637 return ERR_PTR(-EFAULT);
1641 static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
1643 return stack_guard_page_start(vma, addr) ||
1644 stack_guard_page_end(vma, addr+PAGE_SIZE);
1648 * __get_user_pages() - pin user pages in memory
1649 * @tsk: task_struct of target task
1650 * @mm: mm_struct of target mm
1651 * @start: starting user address
1652 * @nr_pages: number of pages from start to pin
1653 * @gup_flags: flags modifying pin behaviour
1654 * @pages: array that receives pointers to the pages pinned.
1655 * Should be at least nr_pages long. Or NULL, if caller
1656 * only intends to ensure the pages are faulted in.
1657 * @vmas: array of pointers to vmas corresponding to each page.
1658 * Or NULL if the caller does not require them.
1659 * @nonblocking: whether waiting for disk IO or mmap_sem contention
1661 * Returns number of pages pinned. This may be fewer than the number
1662 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1663 * were pinned, returns -errno. Each page returned must be released
1664 * with a put_page() call when it is finished with. vmas will only
1665 * remain valid while mmap_sem is held.
1667 * Must be called with mmap_sem held for read or write.
1669 * __get_user_pages walks a process's page tables and takes a reference to
1670 * each struct page that each user address corresponds to at a given
1671 * instant. That is, it takes the page that would be accessed if a user
1672 * thread accesses the given user virtual address at that instant.
1674 * This does not guarantee that the page exists in the user mappings when
1675 * __get_user_pages returns, and there may even be a completely different
1676 * page there in some cases (eg. if mmapped pagecache has been invalidated
1677 * and subsequently re faulted). However it does guarantee that the page
1678 * won't be freed completely. And mostly callers simply care that the page
1679 * contains data that was valid *at some point in time*. Typically, an IO
1680 * or similar operation cannot guarantee anything stronger anyway because
1681 * locks can't be held over the syscall boundary.
1683 * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
1684 * the page is written to, set_page_dirty (or set_page_dirty_lock, as
1685 * appropriate) must be called after the page is finished with, and
1686 * before put_page is called.
1688 * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
1689 * or mmap_sem contention, and if waiting is needed to pin all pages,
1690 * *@nonblocking will be set to 0.
1692 * In most cases, get_user_pages or get_user_pages_fast should be used
1693 * instead of __get_user_pages. __get_user_pages should be used only if
1694 * you need some special @gup_flags.
1696 long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1697 unsigned long start, unsigned long nr_pages,
1698 unsigned int gup_flags, struct page **pages,
1699 struct vm_area_struct **vmas, int *nonblocking)
1702 unsigned long vm_flags;
1703 unsigned int page_mask;
1708 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1711 * Require read or write permissions.
1712 * If FOLL_FORCE is set, we only require the "MAY" flags.
1714 vm_flags = (gup_flags & FOLL_WRITE) ?
1715 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1716 vm_flags &= (gup_flags & FOLL_FORCE) ?
1717 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1720 * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
1721 * would be called on PROT_NONE ranges. We must never invoke
1722 * handle_mm_fault on PROT_NONE ranges or the NUMA hinting
1723 * page faults would unprotect the PROT_NONE ranges if
1724 * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd
1725 * bitflag. So to avoid that, don't set FOLL_NUMA if
1726 * FOLL_FORCE is set.
1728 if (!(gup_flags & FOLL_FORCE))
1729 gup_flags |= FOLL_NUMA;
1734 struct vm_area_struct *vma;
1736 vma = find_extend_vma(mm, start);
1737 if (!vma && in_gate_area(mm, start)) {
1738 unsigned long pg = start & PAGE_MASK;
1744 /* user gate pages are read-only */
1745 if (gup_flags & FOLL_WRITE)
1746 return i ? : -EFAULT;
1748 pgd = pgd_offset_k(pg);
1750 pgd = pgd_offset_gate(mm, pg);
1751 BUG_ON(pgd_none(*pgd));
1752 pud = pud_offset(pgd, pg);
1753 BUG_ON(pud_none(*pud));
1754 pmd = pmd_offset(pud, pg);
1756 return i ? : -EFAULT;
1757 VM_BUG_ON(pmd_trans_huge(*pmd));
1758 pte = pte_offset_map(pmd, pg);
1759 if (pte_none(*pte)) {
1761 return i ? : -EFAULT;
1763 vma = get_gate_vma(mm);
1767 page = vm_normal_page(vma, start, *pte);
1769 if (!(gup_flags & FOLL_DUMP) &&
1770 is_zero_pfn(pte_pfn(*pte)))
1771 page = pte_page(*pte);
1774 return i ? : -EFAULT;
1786 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1787 !(vm_flags & vma->vm_flags))
1788 return i ? : -EFAULT;
1790 if (is_vm_hugetlb_page(vma)) {
1791 i = follow_hugetlb_page(mm, vma, pages, vmas,
1792 &start, &nr_pages, i, gup_flags);
1798 unsigned int foll_flags = gup_flags;
1799 unsigned int page_increm;
1802 * If we have a pending SIGKILL, don't keep faulting
1803 * pages and potentially allocating memory.
1805 if (unlikely(fatal_signal_pending(current)))
1806 return i ? i : -ERESTARTSYS;
1809 while (!(page = follow_page_mask(vma, start,
1810 foll_flags, &page_mask))) {
1812 unsigned int fault_flags = 0;
1814 /* For mlock, just skip the stack guard page. */
1815 if (foll_flags & FOLL_MLOCK) {
1816 if (stack_guard_page(vma, start))
1819 if (foll_flags & FOLL_WRITE)
1820 fault_flags |= FAULT_FLAG_WRITE;
1822 fault_flags |= FAULT_FLAG_ALLOW_RETRY;
1823 if (foll_flags & FOLL_NOWAIT)
1824 fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT);
1826 ret = handle_mm_fault(mm, vma, start,
1829 if (ret & VM_FAULT_ERROR) {
1830 if (ret & VM_FAULT_OOM)
1831 return i ? i : -ENOMEM;
1832 if (ret & (VM_FAULT_HWPOISON |
1833 VM_FAULT_HWPOISON_LARGE)) {
1836 else if (gup_flags & FOLL_HWPOISON)
1841 if (ret & VM_FAULT_SIGBUS)
1842 return i ? i : -EFAULT;
1847 if (ret & VM_FAULT_MAJOR)
1853 if (ret & VM_FAULT_RETRY) {
1860 * The VM_FAULT_WRITE bit tells us that
1861 * do_wp_page has broken COW when necessary,
1862 * even if maybe_mkwrite decided not to set
1863 * pte_write. We can thus safely do subsequent
1864 * page lookups as if they were reads. But only
1865 * do so when looping for pte_write is futile:
1866 * in some cases userspace may also be wanting
1867 * to write to the gotten user page, which a
1868 * read fault here might prevent (a readonly
1869 * page might get reCOWed by userspace write).
1871 if ((ret & VM_FAULT_WRITE) &&
1872 !(vma->vm_flags & VM_WRITE))
1873 foll_flags &= ~FOLL_WRITE;
1878 return i ? i : PTR_ERR(page);
1882 flush_anon_page(vma, page, start);
1883 flush_dcache_page(page);
1891 page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
1892 if (page_increm > nr_pages)
1893 page_increm = nr_pages;
1895 start += page_increm * PAGE_SIZE;
1896 nr_pages -= page_increm;
1897 } while (nr_pages && start < vma->vm_end);
1901 EXPORT_SYMBOL(__get_user_pages);
1904 * fixup_user_fault() - manually resolve a user page fault
1905 * @tsk: the task_struct to use for page fault accounting, or
1906 * NULL if faults are not to be recorded.
1907 * @mm: mm_struct of target mm
1908 * @address: user address
1909 * @fault_flags:flags to pass down to handle_mm_fault()
1911 * This is meant to be called in the specific scenario where for locking reasons
1912 * we try to access user memory in atomic context (within a pagefault_disable()
1913 * section), this returns -EFAULT, and we want to resolve the user fault before
1916 * Typically this is meant to be used by the futex code.
1918 * The main difference with get_user_pages() is that this function will
1919 * unconditionally call handle_mm_fault() which will in turn perform all the
1920 * necessary SW fixup of the dirty and young bits in the PTE, while
1921 * handle_mm_fault() only guarantees to update these in the struct page.
1923 * This is important for some architectures where those bits also gate the
1924 * access permission to the page because they are maintained in software. On
1925 * such architectures, gup() will not be enough to make a subsequent access
1928 * This should be called with the mm_sem held for read.
1930 int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1931 unsigned long address, unsigned int fault_flags)
1933 struct vm_area_struct *vma;
1936 vma = find_extend_vma(mm, address);
1937 if (!vma || address < vma->vm_start)
1940 ret = handle_mm_fault(mm, vma, address, fault_flags);
1941 if (ret & VM_FAULT_ERROR) {
1942 if (ret & VM_FAULT_OOM)
1944 if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
1946 if (ret & VM_FAULT_SIGBUS)
1951 if (ret & VM_FAULT_MAJOR)
1960 * get_user_pages() - pin user pages in memory
1961 * @tsk: the task_struct to use for page fault accounting, or
1962 * NULL if faults are not to be recorded.
1963 * @mm: mm_struct of target mm
1964 * @start: starting user address
1965 * @nr_pages: number of pages from start to pin
1966 * @write: whether pages will be written to by the caller
1967 * @force: whether to force write access even if user mapping is
1968 * readonly. This will result in the page being COWed even
1969 * in MAP_SHARED mappings. You do not want this.
1970 * @pages: array that receives pointers to the pages pinned.
1971 * Should be at least nr_pages long. Or NULL, if caller
1972 * only intends to ensure the pages are faulted in.
1973 * @vmas: array of pointers to vmas corresponding to each page.
1974 * Or NULL if the caller does not require them.
1976 * Returns number of pages pinned. This may be fewer than the number
1977 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1978 * were pinned, returns -errno. Each page returned must be released
1979 * with a put_page() call when it is finished with. vmas will only
1980 * remain valid while mmap_sem is held.
1982 * Must be called with mmap_sem held for read or write.
1984 * get_user_pages walks a process's page tables and takes a reference to
1985 * each struct page that each user address corresponds to at a given
1986 * instant. That is, it takes the page that would be accessed if a user
1987 * thread accesses the given user virtual address at that instant.
1989 * This does not guarantee that the page exists in the user mappings when
1990 * get_user_pages returns, and there may even be a completely different
1991 * page there in some cases (eg. if mmapped pagecache has been invalidated
1992 * and subsequently re faulted). However it does guarantee that the page
1993 * won't be freed completely. And mostly callers simply care that the page
1994 * contains data that was valid *at some point in time*. Typically, an IO
1995 * or similar operation cannot guarantee anything stronger anyway because
1996 * locks can't be held over the syscall boundary.
1998 * If write=0, the page must not be written to. If the page is written to,
1999 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
2000 * after the page is finished with, and before put_page is called.
2002 * get_user_pages is typically used for fewer-copy IO operations, to get a
2003 * handle on the memory by some means other than accesses via the user virtual
2004 * addresses. The pages may be submitted for DMA to devices or accessed via
2005 * their kernel linear mapping (via the kmap APIs). Care should be taken to
2006 * use the correct cache flushing APIs.
2008 * See also get_user_pages_fast, for performance critical applications.
2010 long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
2011 unsigned long start, unsigned long nr_pages, int write,
2012 int force, struct page **pages, struct vm_area_struct **vmas)
2014 int flags = FOLL_TOUCH;
2019 flags |= FOLL_WRITE;
2021 flags |= FOLL_FORCE;
2023 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
2026 EXPORT_SYMBOL(get_user_pages);
2029 * get_dump_page() - pin user page in memory while writing it to core dump
2030 * @addr: user address
2032 * Returns struct page pointer of user page pinned for dump,
2033 * to be freed afterwards by page_cache_release() or put_page().
2035 * Returns NULL on any kind of failure - a hole must then be inserted into
2036 * the corefile, to preserve alignment with its headers; and also returns
2037 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
2038 * allowing a hole to be left in the corefile to save diskspace.
2040 * Called without mmap_sem, but after all other threads have been killed.
2042 #ifdef CONFIG_ELF_CORE
2043 struct page *get_dump_page(unsigned long addr)
2045 struct vm_area_struct *vma;
2048 if (__get_user_pages(current, current->mm, addr, 1,
2049 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
2052 flush_cache_page(vma, addr, page_to_pfn(page));
2055 #endif /* CONFIG_ELF_CORE */
2057 pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
2060 pgd_t * pgd = pgd_offset(mm, addr);
2061 pud_t * pud = pud_alloc(mm, pgd, addr);
2063 pmd_t * pmd = pmd_alloc(mm, pud, addr);
2065 VM_BUG_ON(pmd_trans_huge(*pmd));
2066 return pte_alloc_map_lock(mm, pmd, addr, ptl);
2073 * This is the old fallback for page remapping.
2075 * For historical reasons, it only allows reserved pages. Only
2076 * old drivers should use this, and they needed to mark their
2077 * pages reserved for the old functions anyway.
2079 static int insert_page(struct vm_area_struct *vma, unsigned long addr,
2080 struct page *page, pgprot_t prot)
2082 struct mm_struct *mm = vma->vm_mm;
2091 flush_dcache_page(page);
2092 pte = get_locked_pte(mm, addr, &ptl);
2096 if (!pte_none(*pte))
2099 /* Ok, finally just insert the thing.. */
2101 inc_mm_counter_fast(mm, MM_FILEPAGES);
2102 page_add_file_rmap(page);
2103 set_pte_at(mm, addr, pte, mk_pte(page, prot));
2106 pte_unmap_unlock(pte, ptl);
2109 pte_unmap_unlock(pte, ptl);
2115 * vm_insert_page - insert single page into user vma
2116 * @vma: user vma to map to
2117 * @addr: target user address of this page
2118 * @page: source kernel page
2120 * This allows drivers to insert individual pages they've allocated
2123 * The page has to be a nice clean _individual_ kernel allocation.
2124 * If you allocate a compound page, you need to have marked it as
2125 * such (__GFP_COMP), or manually just split the page up yourself
2126 * (see split_page()).
2128 * NOTE! Traditionally this was done with "remap_pfn_range()" which
2129 * took an arbitrary page protection parameter. This doesn't allow
2130 * that. Your vma protection will have to be set up correctly, which
2131 * means that if you want a shared writable mapping, you'd better
2132 * ask for a shared writable mapping!
2134 * The page does not need to be reserved.
2136 * Usually this function is called from f_op->mmap() handler
2137 * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
2138 * Caller must set VM_MIXEDMAP on vma if it wants to call this
2139 * function from other places, for example from page-fault handler.
2141 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
2144 if (addr < vma->vm_start || addr >= vma->vm_end)
2146 if (!page_count(page))
2148 if (!(vma->vm_flags & VM_MIXEDMAP)) {
2149 BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem));
2150 BUG_ON(vma->vm_flags & VM_PFNMAP);
2151 vma->vm_flags |= VM_MIXEDMAP;
2153 return insert_page(vma, addr, page, vma->vm_page_prot);
2155 EXPORT_SYMBOL(vm_insert_page);
2157 static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2158 unsigned long pfn, pgprot_t prot)
2160 struct mm_struct *mm = vma->vm_mm;
2166 pte = get_locked_pte(mm, addr, &ptl);
2170 if (!pte_none(*pte))
2173 /* Ok, finally just insert the thing.. */
2174 entry = pte_mkspecial(pfn_pte(pfn, prot));
2175 set_pte_at(mm, addr, pte, entry);
2176 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
2180 pte_unmap_unlock(pte, ptl);
2186 * vm_insert_pfn - insert single pfn into user vma
2187 * @vma: user vma to map to
2188 * @addr: target user address of this page
2189 * @pfn: source kernel pfn
2191 * Similar to vm_insert_page, this allows drivers to insert individual pages
2192 * they've allocated into a user vma. Same comments apply.
2194 * This function should only be called from a vm_ops->fault handler, and
2195 * in that case the handler should return NULL.
2197 * vma cannot be a COW mapping.
2199 * As this is called only for pages that do not currently exist, we
2200 * do not need to flush old virtual caches or the TLB.
2202 int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2206 pgprot_t pgprot = vma->vm_page_prot;
2208 * Technically, architectures with pte_special can avoid all these
2209 * restrictions (same for remap_pfn_range). However we would like
2210 * consistency in testing and feature parity among all, so we should
2211 * try to keep these invariants in place for everybody.
2213 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
2214 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
2215 (VM_PFNMAP|VM_MIXEDMAP));
2216 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
2217 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
2219 if (addr < vma->vm_start || addr >= vma->vm_end)
2221 if (track_pfn_insert(vma, &pgprot, pfn))
2224 ret = insert_pfn(vma, addr, pfn, pgprot);
2228 EXPORT_SYMBOL(vm_insert_pfn);
2230 int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2233 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
2235 if (addr < vma->vm_start || addr >= vma->vm_end)
2239 * If we don't have pte special, then we have to use the pfn_valid()
2240 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
2241 * refcount the page if pfn_valid is true (hence insert_page rather
2242 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
2243 * without pte special, it would there be refcounted as a normal page.
2245 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
2248 page = pfn_to_page(pfn);
2249 return insert_page(vma, addr, page, vma->vm_page_prot);
2251 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
2253 EXPORT_SYMBOL(vm_insert_mixed);
2256 * maps a range of physical memory into the requested pages. the old
2257 * mappings are removed. any references to nonexistent pages results
2258 * in null mappings (currently treated as "copy-on-access")
2260 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
2261 unsigned long addr, unsigned long end,
2262 unsigned long pfn, pgprot_t prot)
2267 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
2270 arch_enter_lazy_mmu_mode();
2272 BUG_ON(!pte_none(*pte));
2273 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
2275 } while (pte++, addr += PAGE_SIZE, addr != end);
2276 arch_leave_lazy_mmu_mode();
2277 pte_unmap_unlock(pte - 1, ptl);
2281 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
2282 unsigned long addr, unsigned long end,
2283 unsigned long pfn, pgprot_t prot)
2288 pfn -= addr >> PAGE_SHIFT;
2289 pmd = pmd_alloc(mm, pud, addr);
2292 VM_BUG_ON(pmd_trans_huge(*pmd));
2294 next = pmd_addr_end(addr, end);
2295 if (remap_pte_range(mm, pmd, addr, next,
2296 pfn + (addr >> PAGE_SHIFT), prot))
2298 } while (pmd++, addr = next, addr != end);
2302 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
2303 unsigned long addr, unsigned long end,
2304 unsigned long pfn, pgprot_t prot)
2309 pfn -= addr >> PAGE_SHIFT;
2310 pud = pud_alloc(mm, pgd, addr);
2314 next = pud_addr_end(addr, end);
2315 if (remap_pmd_range(mm, pud, addr, next,
2316 pfn + (addr >> PAGE_SHIFT), prot))
2318 } while (pud++, addr = next, addr != end);
2323 * remap_pfn_range - remap kernel memory to userspace
2324 * @vma: user vma to map to
2325 * @addr: target user address to start at
2326 * @pfn: physical address of kernel memory
2327 * @size: size of map area
2328 * @prot: page protection flags for this mapping
2330 * Note: this is only safe if the mm semaphore is held when called.
2332 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
2333 unsigned long pfn, unsigned long size, pgprot_t prot)
2337 unsigned long end = addr + PAGE_ALIGN(size);
2338 struct mm_struct *mm = vma->vm_mm;
2342 * Physically remapped pages are special. Tell the
2343 * rest of the world about it:
2344 * VM_IO tells people not to look at these pages
2345 * (accesses can have side effects).
2346 * VM_PFNMAP tells the core MM that the base pages are just
2347 * raw PFN mappings, and do not have a "struct page" associated
2350 * Disable vma merging and expanding with mremap().
2352 * Omit vma from core dump, even when VM_IO turned off.
2354 * There's a horrible special case to handle copy-on-write
2355 * behaviour that some programs depend on. We mark the "original"
2356 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
2357 * See vm_normal_page() for details.
2359 if (is_cow_mapping(vma->vm_flags)) {
2360 if (addr != vma->vm_start || end != vma->vm_end)
2362 vma->vm_pgoff = pfn;
2365 err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
2369 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
2371 BUG_ON(addr >= end);
2372 pfn -= addr >> PAGE_SHIFT;
2373 pgd = pgd_offset(mm, addr);
2374 flush_cache_range(vma, addr, end);
2376 next = pgd_addr_end(addr, end);
2377 err = remap_pud_range(mm, pgd, addr, next,
2378 pfn + (addr >> PAGE_SHIFT), prot);
2381 } while (pgd++, addr = next, addr != end);
2384 untrack_pfn(vma, pfn, PAGE_ALIGN(size));
2388 EXPORT_SYMBOL(remap_pfn_range);
2391 * vm_iomap_memory - remap memory to userspace
2392 * @vma: user vma to map to
2393 * @start: start of area
2394 * @len: size of area
2396 * This is a simplified io_remap_pfn_range() for common driver use. The
2397 * driver just needs to give us the physical memory range to be mapped,
2398 * we'll figure out the rest from the vma information.
2400 * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
2401 * whatever write-combining details or similar.
2403 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
2405 unsigned long vm_len, pfn, pages;
2407 /* Check that the physical memory area passed in looks valid */
2408 if (start + len < start)
2411 * You *really* shouldn't map things that aren't page-aligned,
2412 * but we've historically allowed it because IO memory might
2413 * just have smaller alignment.
2415 len += start & ~PAGE_MASK;
2416 pfn = start >> PAGE_SHIFT;
2417 pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
2418 if (pfn + pages < pfn)
2421 /* We start the mapping 'vm_pgoff' pages into the area */
2422 if (vma->vm_pgoff > pages)
2424 pfn += vma->vm_pgoff;
2425 pages -= vma->vm_pgoff;
2427 /* Can we fit all of the mapping? */
2428 vm_len = vma->vm_end - vma->vm_start;
2429 if (vm_len >> PAGE_SHIFT > pages)
2432 /* Ok, let it rip */
2433 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
2435 EXPORT_SYMBOL(vm_iomap_memory);
2437 static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
2438 unsigned long addr, unsigned long end,
2439 pte_fn_t fn, void *data)
2444 spinlock_t *uninitialized_var(ptl);
2446 pte = (mm == &init_mm) ?
2447 pte_alloc_kernel(pmd, addr) :
2448 pte_alloc_map_lock(mm, pmd, addr, &ptl);
2452 BUG_ON(pmd_huge(*pmd));
2454 arch_enter_lazy_mmu_mode();
2456 token = pmd_pgtable(*pmd);
2459 err = fn(pte++, token, addr, data);
2462 } while (addr += PAGE_SIZE, addr != end);
2464 arch_leave_lazy_mmu_mode();
2467 pte_unmap_unlock(pte-1, ptl);
2471 static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
2472 unsigned long addr, unsigned long end,
2473 pte_fn_t fn, void *data)
2479 BUG_ON(pud_huge(*pud));
2481 pmd = pmd_alloc(mm, pud, addr);
2485 next = pmd_addr_end(addr, end);
2486 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
2489 } while (pmd++, addr = next, addr != end);
2493 static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
2494 unsigned long addr, unsigned long end,
2495 pte_fn_t fn, void *data)
2501 pud = pud_alloc(mm, pgd, addr);
2505 next = pud_addr_end(addr, end);
2506 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
2509 } while (pud++, addr = next, addr != end);
2514 * Scan a region of virtual memory, filling in page tables as necessary
2515 * and calling a provided function on each leaf page table.
2517 int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2518 unsigned long size, pte_fn_t fn, void *data)
2522 unsigned long end = addr + size;
2525 BUG_ON(addr >= end);
2526 pgd = pgd_offset(mm, addr);
2528 next = pgd_addr_end(addr, end);
2529 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2532 } while (pgd++, addr = next, addr != end);
2536 EXPORT_SYMBOL_GPL(apply_to_page_range);
2539 * handle_pte_fault chooses page fault handler according to an entry
2540 * which was read non-atomically. Before making any commitment, on
2541 * those architectures or configurations (e.g. i386 with PAE) which
2542 * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
2543 * must check under lock before unmapping the pte and proceeding
2544 * (but do_wp_page is only called after already making such a check;
2545 * and do_anonymous_page can safely check later on).
2547 static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2548 pte_t *page_table, pte_t orig_pte)
2551 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2552 if (sizeof(pte_t) > sizeof(unsigned long)) {
2553 spinlock_t *ptl = pte_lockptr(mm, pmd);
2555 same = pte_same(*page_table, orig_pte);
2559 pte_unmap(page_table);
2563 static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2566 * If the source page was a PFN mapping, we don't have
2567 * a "struct page" for it. We do a best-effort copy by
2568 * just copying from the original user address. If that
2569 * fails, we just zero-fill it. Live with it.
2571 if (unlikely(!src)) {
2572 void *kaddr = kmap_atomic(dst);
2573 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2576 * This really shouldn't fail, because the page is there
2577 * in the page tables. But it might just be unreadable,
2578 * in which case we just give up and fill the result with
2581 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2583 kunmap_atomic(kaddr);
2584 flush_dcache_page(dst);
2586 copy_user_highpage(dst, src, va, vma);
2590 * This routine handles present pages, when users try to write
2591 * to a shared page. It is done by copying the page to a new address
2592 * and decrementing the shared-page counter for the old page.
2594 * Note that this routine assumes that the protection checks have been
2595 * done by the caller (the low-level page fault routine in most cases).
2596 * Thus we can safely just mark it writable once we've done any necessary
2599 * We also mark the page dirty at this point even though the page will
2600 * change only once the write actually happens. This avoids a few races,
2601 * and potentially makes it more efficient.
2603 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2604 * but allow concurrent faults), with pte both mapped and locked.
2605 * We return with mmap_sem still held, but pte unmapped and unlocked.
2607 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2608 unsigned long address, pte_t *page_table, pmd_t *pmd,
2609 spinlock_t *ptl, pte_t orig_pte)
2612 struct page *old_page, *new_page = NULL;
2615 int page_mkwrite = 0;
2616 struct page *dirty_page = NULL;
2617 unsigned long mmun_start = 0; /* For mmu_notifiers */
2618 unsigned long mmun_end = 0; /* For mmu_notifiers */
2620 old_page = vm_normal_page(vma, address, orig_pte);
2623 * VM_MIXEDMAP !pfn_valid() case
2625 * We should not cow pages in a shared writeable mapping.
2626 * Just mark the pages writable as we can't do any dirty
2627 * accounting on raw pfn maps.
2629 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2630 (VM_WRITE|VM_SHARED))
2636 * Take out anonymous pages first, anonymous shared vmas are
2637 * not dirty accountable.
2639 if (PageAnon(old_page) && !PageKsm(old_page)) {
2640 if (!trylock_page(old_page)) {
2641 page_cache_get(old_page);
2642 pte_unmap_unlock(page_table, ptl);
2643 lock_page(old_page);
2644 page_table = pte_offset_map_lock(mm, pmd, address,
2646 if (!pte_same(*page_table, orig_pte)) {
2647 unlock_page(old_page);
2650 page_cache_release(old_page);
2652 if (reuse_swap_page(old_page)) {
2654 * The page is all ours. Move it to our anon_vma so
2655 * the rmap code will not search our parent or siblings.
2656 * Protected against the rmap code by the page lock.
2658 page_move_anon_rmap(old_page, vma, address);
2659 unlock_page(old_page);
2662 unlock_page(old_page);
2663 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2664 (VM_WRITE|VM_SHARED))) {
2666 * Only catch write-faults on shared writable pages,
2667 * read-only shared pages can get COWed by
2668 * get_user_pages(.write=1, .force=1).
2670 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2671 struct vm_fault vmf;
2674 vmf.virtual_address = (void __user *)(address &
2676 vmf.pgoff = old_page->index;
2677 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2678 vmf.page = old_page;
2681 * Notify the address space that the page is about to
2682 * become writable so that it can prohibit this or wait
2683 * for the page to get into an appropriate state.
2685 * We do this without the lock held, so that it can
2686 * sleep if it needs to.
2688 page_cache_get(old_page);
2689 pte_unmap_unlock(page_table, ptl);
2691 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2693 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2695 goto unwritable_page;
2697 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2698 lock_page(old_page);
2699 if (!old_page->mapping) {
2700 ret = 0; /* retry the fault */
2701 unlock_page(old_page);
2702 goto unwritable_page;
2705 VM_BUG_ON(!PageLocked(old_page));
2708 * Since we dropped the lock we need to revalidate
2709 * the PTE as someone else may have changed it. If
2710 * they did, we just return, as we can count on the
2711 * MMU to tell us if they didn't also make it writable.
2713 page_table = pte_offset_map_lock(mm, pmd, address,
2715 if (!pte_same(*page_table, orig_pte)) {
2716 unlock_page(old_page);
2722 dirty_page = old_page;
2723 get_page(dirty_page);
2726 flush_cache_page(vma, address, pte_pfn(orig_pte));
2727 entry = pte_mkyoung(orig_pte);
2728 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2729 if (ptep_set_access_flags(vma, address, page_table, entry,1))
2730 update_mmu_cache(vma, address, page_table);
2731 pte_unmap_unlock(page_table, ptl);
2732 ret |= VM_FAULT_WRITE;
2738 * Yes, Virginia, this is actually required to prevent a race
2739 * with clear_page_dirty_for_io() from clearing the page dirty
2740 * bit after it clear all dirty ptes, but before a racing
2741 * do_wp_page installs a dirty pte.
2743 * __do_fault is protected similarly.
2745 if (!page_mkwrite) {
2746 wait_on_page_locked(dirty_page);
2747 set_page_dirty_balance(dirty_page, page_mkwrite);
2748 /* file_update_time outside page_lock */
2750 file_update_time(vma->vm_file);
2752 put_page(dirty_page);
2754 struct address_space *mapping = dirty_page->mapping;
2756 set_page_dirty(dirty_page);
2757 unlock_page(dirty_page);
2758 page_cache_release(dirty_page);
2761 * Some device drivers do not set page.mapping
2762 * but still dirty their pages
2764 balance_dirty_pages_ratelimited(mapping);
2772 * Ok, we need to copy. Oh, well..
2774 page_cache_get(old_page);
2776 pte_unmap_unlock(page_table, ptl);
2778 if (unlikely(anon_vma_prepare(vma)))
2781 if (is_zero_pfn(pte_pfn(orig_pte))) {
2782 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2786 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2789 cow_user_page(new_page, old_page, address, vma);
2791 __SetPageUptodate(new_page);
2793 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2796 mmun_start = address & PAGE_MASK;
2797 mmun_end = mmun_start + PAGE_SIZE;
2798 mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2801 * Re-check the pte - we dropped the lock
2803 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2804 if (likely(pte_same(*page_table, orig_pte))) {
2806 if (!PageAnon(old_page)) {
2807 dec_mm_counter_fast(mm, MM_FILEPAGES);
2808 inc_mm_counter_fast(mm, MM_ANONPAGES);
2811 inc_mm_counter_fast(mm, MM_ANONPAGES);
2812 flush_cache_page(vma, address, pte_pfn(orig_pte));
2813 entry = mk_pte(new_page, vma->vm_page_prot);
2814 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2816 * Clear the pte entry and flush it first, before updating the
2817 * pte with the new entry. This will avoid a race condition
2818 * seen in the presence of one thread doing SMC and another
2821 ptep_clear_flush(vma, address, page_table);
2822 page_add_new_anon_rmap(new_page, vma, address);
2824 * We call the notify macro here because, when using secondary
2825 * mmu page tables (such as kvm shadow page tables), we want the
2826 * new page to be mapped directly into the secondary page table.
2828 set_pte_at_notify(mm, address, page_table, entry);
2829 update_mmu_cache(vma, address, page_table);
2832 * Only after switching the pte to the new page may
2833 * we remove the mapcount here. Otherwise another
2834 * process may come and find the rmap count decremented
2835 * before the pte is switched to the new page, and
2836 * "reuse" the old page writing into it while our pte
2837 * here still points into it and can be read by other
2840 * The critical issue is to order this
2841 * page_remove_rmap with the ptp_clear_flush above.
2842 * Those stores are ordered by (if nothing else,)
2843 * the barrier present in the atomic_add_negative
2844 * in page_remove_rmap.
2846 * Then the TLB flush in ptep_clear_flush ensures that
2847 * no process can access the old page before the
2848 * decremented mapcount is visible. And the old page
2849 * cannot be reused until after the decremented
2850 * mapcount is visible. So transitively, TLBs to
2851 * old page will be flushed before it can be reused.
2853 page_remove_rmap(old_page);
2856 /* Free the old page.. */
2857 new_page = old_page;
2858 ret |= VM_FAULT_WRITE;
2860 mem_cgroup_uncharge_page(new_page);
2863 page_cache_release(new_page);
2865 pte_unmap_unlock(page_table, ptl);
2866 if (mmun_end > mmun_start)
2867 mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2870 * Don't let another task, with possibly unlocked vma,
2871 * keep the mlocked page.
2873 if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) {
2874 lock_page(old_page); /* LRU manipulation */
2875 munlock_vma_page(old_page);
2876 unlock_page(old_page);
2878 page_cache_release(old_page);
2882 page_cache_release(new_page);
2885 page_cache_release(old_page);
2886 return VM_FAULT_OOM;
2889 page_cache_release(old_page);
2893 static void unmap_mapping_range_vma(struct vm_area_struct *vma,
2894 unsigned long start_addr, unsigned long end_addr,
2895 struct zap_details *details)
2897 zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
2900 static inline void unmap_mapping_range_tree(struct rb_root *root,
2901 struct zap_details *details)
2903 struct vm_area_struct *vma;
2904 pgoff_t vba, vea, zba, zea;
2906 vma_interval_tree_foreach(vma, root,
2907 details->first_index, details->last_index) {
2909 vba = vma->vm_pgoff;
2910 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2911 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2912 zba = details->first_index;
2915 zea = details->last_index;
2919 unmap_mapping_range_vma(vma,
2920 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2921 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2926 static inline void unmap_mapping_range_list(struct list_head *head,
2927 struct zap_details *details)
2929 struct vm_area_struct *vma;
2932 * In nonlinear VMAs there is no correspondence between virtual address
2933 * offset and file offset. So we must perform an exhaustive search
2934 * across *all* the pages in each nonlinear VMA, not just the pages
2935 * whose virtual address lies outside the file truncation point.
2937 list_for_each_entry(vma, head, shared.nonlinear) {
2938 details->nonlinear_vma = vma;
2939 unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
2944 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2945 * @mapping: the address space containing mmaps to be unmapped.
2946 * @holebegin: byte in first page to unmap, relative to the start of
2947 * the underlying file. This will be rounded down to a PAGE_SIZE
2948 * boundary. Note that this is different from truncate_pagecache(), which
2949 * must keep the partial page. In contrast, we must get rid of
2951 * @holelen: size of prospective hole in bytes. This will be rounded
2952 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2954 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2955 * but 0 when invalidating pagecache, don't throw away private data.
2957 void unmap_mapping_range(struct address_space *mapping,
2958 loff_t const holebegin, loff_t const holelen, int even_cows)
2960 struct zap_details details;
2961 pgoff_t hba = holebegin >> PAGE_SHIFT;
2962 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2964 /* Check for overflow. */
2965 if (sizeof(holelen) > sizeof(hlen)) {
2967 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2968 if (holeend & ~(long long)ULONG_MAX)
2969 hlen = ULONG_MAX - hba + 1;
2972 details.check_mapping = even_cows? NULL: mapping;
2973 details.nonlinear_vma = NULL;
2974 details.first_index = hba;
2975 details.last_index = hba + hlen - 1;
2976 if (details.last_index < details.first_index)
2977 details.last_index = ULONG_MAX;
2980 mutex_lock(&mapping->i_mmap_mutex);
2981 if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
2982 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2983 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2984 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2985 mutex_unlock(&mapping->i_mmap_mutex);
2987 EXPORT_SYMBOL(unmap_mapping_range);
2990 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2991 * but allow concurrent faults), and pte mapped but not yet locked.
2992 * We return with mmap_sem still held, but pte unmapped and unlocked.
2994 static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2995 unsigned long address, pte_t *page_table, pmd_t *pmd,
2996 unsigned int flags, pte_t orig_pte)
2999 struct page *page, *swapcache;
3003 struct mem_cgroup *ptr;
3007 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3010 entry = pte_to_swp_entry(orig_pte);
3011 if (unlikely(non_swap_entry(entry))) {
3012 if (is_migration_entry(entry)) {
3013 migration_entry_wait(mm, pmd, address);
3014 } else if (is_hwpoison_entry(entry)) {
3015 ret = VM_FAULT_HWPOISON;
3017 print_bad_pte(vma, address, orig_pte, NULL);
3018 ret = VM_FAULT_SIGBUS;
3022 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
3023 page = lookup_swap_cache(entry);
3025 page = swapin_readahead(entry,
3026 GFP_HIGHUSER_MOVABLE, vma, address);
3029 * Back out if somebody else faulted in this pte
3030 * while we released the pte lock.
3032 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3033 if (likely(pte_same(*page_table, orig_pte)))
3035 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3039 /* Had to read the page from swap area: Major fault */
3040 ret = VM_FAULT_MAJOR;
3041 count_vm_event(PGMAJFAULT);
3042 mem_cgroup_count_vm_event(mm, PGMAJFAULT);
3043 } else if (PageHWPoison(page)) {
3045 * hwpoisoned dirty swapcache pages are kept for killing
3046 * owner processes (which may be unknown at hwpoison time)
3048 ret = VM_FAULT_HWPOISON;
3049 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3055 locked = lock_page_or_retry(page, mm, flags);
3057 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3059 ret |= VM_FAULT_RETRY;
3064 * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
3065 * release the swapcache from under us. The page pin, and pte_same
3066 * test below, are not enough to exclude that. Even if it is still
3067 * swapcache, we need to check that the page's swap has not changed.
3069 if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
3072 page = ksm_might_need_to_copy(page, vma, address);
3073 if (unlikely(!page)) {
3079 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
3085 * Back out if somebody else already faulted in this pte.
3087 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3088 if (unlikely(!pte_same(*page_table, orig_pte)))
3091 if (unlikely(!PageUptodate(page))) {
3092 ret = VM_FAULT_SIGBUS;
3097 * The page isn't present yet, go ahead with the fault.
3099 * Be careful about the sequence of operations here.
3100 * To get its accounting right, reuse_swap_page() must be called
3101 * while the page is counted on swap but not yet in mapcount i.e.
3102 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
3103 * must be called after the swap_free(), or it will never succeed.
3104 * Because delete_from_swap_page() may be called by reuse_swap_page(),
3105 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
3106 * in page->private. In this case, a record in swap_cgroup is silently
3107 * discarded at swap_free().
3110 inc_mm_counter_fast(mm, MM_ANONPAGES);
3111 dec_mm_counter_fast(mm, MM_SWAPENTS);
3112 pte = mk_pte(page, vma->vm_page_prot);
3113 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
3114 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
3115 flags &= ~FAULT_FLAG_WRITE;
3116 ret |= VM_FAULT_WRITE;
3119 flush_icache_page(vma, page);
3120 set_pte_at(mm, address, page_table, pte);
3121 if (page == swapcache)
3122 do_page_add_anon_rmap(page, vma, address, exclusive);
3123 else /* ksm created a completely new copy */
3124 page_add_new_anon_rmap(page, vma, address);
3125 /* It's better to call commit-charge after rmap is established */
3126 mem_cgroup_commit_charge_swapin(page, ptr);
3129 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
3130 try_to_free_swap(page);
3132 if (page != swapcache) {
3134 * Hold the lock to avoid the swap entry to be reused
3135 * until we take the PT lock for the pte_same() check
3136 * (to avoid false positives from pte_same). For
3137 * further safety release the lock after the swap_free
3138 * so that the swap count won't change under a
3139 * parallel locked swapcache.
3141 unlock_page(swapcache);
3142 page_cache_release(swapcache);
3145 if (flags & FAULT_FLAG_WRITE) {
3146 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
3147 if (ret & VM_FAULT_ERROR)
3148 ret &= VM_FAULT_ERROR;
3152 /* No need to invalidate - it was non-present before */
3153 update_mmu_cache(vma, address, page_table);
3155 pte_unmap_unlock(page_table, ptl);
3159 mem_cgroup_cancel_charge_swapin(ptr);
3160 pte_unmap_unlock(page_table, ptl);
3164 page_cache_release(page);
3165 if (page != swapcache) {
3166 unlock_page(swapcache);
3167 page_cache_release(swapcache);
3173 * This is like a special single-page "expand_{down|up}wards()",
3174 * except we must first make sure that 'address{-|+}PAGE_SIZE'
3175 * doesn't hit another vma.
3177 static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
3179 address &= PAGE_MASK;
3180 if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
3181 struct vm_area_struct *prev = vma->vm_prev;
3184 * Is there a mapping abutting this one below?
3186 * That's only ok if it's the same stack mapping
3187 * that has gotten split..
3189 if (prev && prev->vm_end == address)
3190 return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
3192 expand_downwards(vma, address - PAGE_SIZE);
3194 if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
3195 struct vm_area_struct *next = vma->vm_next;
3197 /* As VM_GROWSDOWN but s/below/above/ */
3198 if (next && next->vm_start == address + PAGE_SIZE)
3199 return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
3201 expand_upwards(vma, address + PAGE_SIZE);
3207 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3208 * but allow concurrent faults), and pte mapped but not yet locked.
3209 * We return with mmap_sem still held, but pte unmapped and unlocked.
3211 static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
3212 unsigned long address, pte_t *page_table, pmd_t *pmd,
3219 pte_unmap(page_table);
3221 /* Check if we need to add a guard page to the stack */
3222 if (check_stack_guard_page(vma, address) < 0)
3223 return VM_FAULT_SIGBUS;
3225 /* Use the zero-page for reads */
3226 if (!(flags & FAULT_FLAG_WRITE)) {
3227 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
3228 vma->vm_page_prot));
3229 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3230 if (!pte_none(*page_table))
3235 /* Allocate our own private page. */
3236 if (unlikely(anon_vma_prepare(vma)))
3238 page = alloc_zeroed_user_highpage_movable(vma, address);
3242 * The memory barrier inside __SetPageUptodate makes sure that
3243 * preceeding stores to the page contents become visible before
3244 * the set_pte_at() write.
3246 __SetPageUptodate(page);
3248 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
3251 entry = mk_pte(page, vma->vm_page_prot);
3252 if (vma->vm_flags & VM_WRITE)
3253 entry = pte_mkwrite(pte_mkdirty(entry));
3255 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3256 if (!pte_none(*page_table))
3259 inc_mm_counter_fast(mm, MM_ANONPAGES);
3260 page_add_new_anon_rmap(page, vma, address);
3262 set_pte_at(mm, address, page_table, entry);
3264 /* No need to invalidate - it was non-present before */
3265 update_mmu_cache(vma, address, page_table);
3267 pte_unmap_unlock(page_table, ptl);
3270 mem_cgroup_uncharge_page(page);
3271 page_cache_release(page);
3274 page_cache_release(page);
3276 return VM_FAULT_OOM;
3280 * __do_fault() tries to create a new page mapping. It aggressively
3281 * tries to share with existing pages, but makes a separate copy if
3282 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
3283 * the next page fault.
3285 * As this is called only for pages that do not currently exist, we
3286 * do not need to flush old virtual caches or the TLB.
3288 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3289 * but allow concurrent faults), and pte neither mapped nor locked.
3290 * We return with mmap_sem still held, but pte unmapped and unlocked.
3292 static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3293 unsigned long address, pmd_t *pmd,
3294 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
3299 struct page *cow_page;
3302 struct page *dirty_page = NULL;
3303 struct vm_fault vmf;
3305 int page_mkwrite = 0;
3308 * If we do COW later, allocate page befor taking lock_page()
3309 * on the file cache page. This will reduce lock holding time.
3311 if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3313 if (unlikely(anon_vma_prepare(vma)))
3314 return VM_FAULT_OOM;
3316 cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
3318 return VM_FAULT_OOM;
3320 if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) {
3321 page_cache_release(cow_page);
3322 return VM_FAULT_OOM;
3327 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
3332 ret = vma->vm_ops->fault(vma, &vmf);
3333 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
3337 if (unlikely(PageHWPoison(vmf.page))) {
3338 if (ret & VM_FAULT_LOCKED)
3339 unlock_page(vmf.page);
3340 ret = VM_FAULT_HWPOISON;
3345 * For consistency in subsequent calls, make the faulted page always
3348 if (unlikely(!(ret & VM_FAULT_LOCKED)))
3349 lock_page(vmf.page);
3351 VM_BUG_ON(!PageLocked(vmf.page));
3354 * Should we do an early C-O-W break?
3357 if (flags & FAULT_FLAG_WRITE) {
3358 if (!(vma->vm_flags & VM_SHARED)) {
3361 copy_user_highpage(page, vmf.page, address, vma);
3362 __SetPageUptodate(page);
3365 * If the page will be shareable, see if the backing
3366 * address space wants to know that the page is about
3367 * to become writable
3369 if (vma->vm_ops->page_mkwrite) {
3373 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
3374 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
3376 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
3378 goto unwritable_page;
3380 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
3382 if (!page->mapping) {
3383 ret = 0; /* retry the fault */
3385 goto unwritable_page;
3388 VM_BUG_ON(!PageLocked(page));
3395 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3398 * This silly early PAGE_DIRTY setting removes a race
3399 * due to the bad i386 page protection. But it's valid
3400 * for other architectures too.
3402 * Note that if FAULT_FLAG_WRITE is set, we either now have
3403 * an exclusive copy of the page, or this is a shared mapping,
3404 * so we can make it writable and dirty to avoid having to
3405 * handle that later.
3407 /* Only go through if we didn't race with anybody else... */
3408 if (likely(pte_same(*page_table, orig_pte))) {
3409 flush_icache_page(vma, page);
3410 entry = mk_pte(page, vma->vm_page_prot);
3411 if (flags & FAULT_FLAG_WRITE)
3412 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
3414 inc_mm_counter_fast(mm, MM_ANONPAGES);
3415 page_add_new_anon_rmap(page, vma, address);
3417 inc_mm_counter_fast(mm, MM_FILEPAGES);
3418 page_add_file_rmap(page);
3419 if (flags & FAULT_FLAG_WRITE) {
3421 get_page(dirty_page);
3424 set_pte_at(mm, address, page_table, entry);
3426 /* no need to invalidate: a not-present page won't be cached */
3427 update_mmu_cache(vma, address, page_table);
3430 mem_cgroup_uncharge_page(cow_page);
3432 page_cache_release(page);
3434 anon = 1; /* no anon but release faulted_page */
3437 pte_unmap_unlock(page_table, ptl);
3440 struct address_space *mapping = page->mapping;
3443 if (set_page_dirty(dirty_page))
3445 unlock_page(dirty_page);
3446 put_page(dirty_page);
3447 if ((dirtied || page_mkwrite) && mapping) {
3449 * Some device drivers do not set page.mapping but still
3452 balance_dirty_pages_ratelimited(mapping);
3455 /* file_update_time outside page_lock */
3456 if (vma->vm_file && !page_mkwrite)
3457 file_update_time(vma->vm_file);
3459 unlock_page(vmf.page);
3461 page_cache_release(vmf.page);
3467 page_cache_release(page);
3470 /* fs's fault handler get error */
3472 mem_cgroup_uncharge_page(cow_page);
3473 page_cache_release(cow_page);
3478 static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3479 unsigned long address, pte_t *page_table, pmd_t *pmd,
3480 unsigned int flags, pte_t orig_pte)
3482 pgoff_t pgoff = (((address & PAGE_MASK)
3483 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3485 pte_unmap(page_table);
3486 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3490 * Fault of a previously existing named mapping. Repopulate the pte
3491 * from the encoded file_pte if possible. This enables swappable
3494 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3495 * but allow concurrent faults), and pte mapped but not yet locked.
3496 * We return with mmap_sem still held, but pte unmapped and unlocked.
3498 static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3499 unsigned long address, pte_t *page_table, pmd_t *pmd,
3500 unsigned int flags, pte_t orig_pte)
3504 flags |= FAULT_FLAG_NONLINEAR;
3506 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3509 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3511 * Page table corrupted: show pte and kill process.
3513 print_bad_pte(vma, address, orig_pte, NULL);
3514 return VM_FAULT_SIGBUS;
3517 pgoff = pte_to_pgoff(orig_pte);
3518 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3521 int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
3522 unsigned long addr, int current_nid)
3526 count_vm_numa_event(NUMA_HINT_FAULTS);
3527 if (current_nid == numa_node_id())
3528 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
3530 return mpol_misplaced(page, vma, addr);
3533 int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3534 unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
3536 struct page *page = NULL;
3538 int current_nid = -1;
3540 bool migrated = false;
3543 * The "pte" at this point cannot be used safely without
3544 * validation through pte_unmap_same(). It's of NUMA type but
3545 * the pfn may be screwed if the read is non atomic.
3547 * ptep_modify_prot_start is not called as this is clearing
3548 * the _PAGE_NUMA bit and it is not really expected that there
3549 * would be concurrent hardware modifications to the PTE.
3551 ptl = pte_lockptr(mm, pmd);
3553 if (unlikely(!pte_same(*ptep, pte))) {
3554 pte_unmap_unlock(ptep, ptl);
3558 pte = pte_mknonnuma(pte);
3559 set_pte_at(mm, addr, ptep, pte);
3560 update_mmu_cache(vma, addr, ptep);
3562 page = vm_normal_page(vma, addr, pte);
3564 pte_unmap_unlock(ptep, ptl);
3568 current_nid = page_to_nid(page);
3569 target_nid = numa_migrate_prep(page, vma, addr, current_nid);
3570 pte_unmap_unlock(ptep, ptl);
3571 if (target_nid == -1) {
3573 * Account for the fault against the current node if it not
3574 * being replaced regardless of where the page is located.
3576 current_nid = numa_node_id();
3581 /* Migrate to the requested node */
3582 migrated = migrate_misplaced_page(page, target_nid);
3584 current_nid = target_nid;
3587 if (current_nid != -1)
3588 task_numa_fault(current_nid, 1, migrated);
3592 /* NUMA hinting page fault entry point for regular pmds */
3593 #ifdef CONFIG_NUMA_BALANCING
3594 static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3595 unsigned long addr, pmd_t *pmdp)
3598 pte_t *pte, *orig_pte;
3599 unsigned long _addr = addr & PMD_MASK;
3600 unsigned long offset;
3603 int local_nid = numa_node_id();
3605 spin_lock(&mm->page_table_lock);
3607 if (pmd_numa(pmd)) {
3608 set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd));
3611 spin_unlock(&mm->page_table_lock);
3616 /* we're in a page fault so some vma must be in the range */
3618 BUG_ON(vma->vm_start >= _addr + PMD_SIZE);
3619 offset = max(_addr, vma->vm_start) & ~PMD_MASK;
3620 VM_BUG_ON(offset >= PMD_SIZE);
3621 orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl);
3622 pte += offset >> PAGE_SHIFT;
3623 for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) {
3624 pte_t pteval = *pte;
3626 int curr_nid = local_nid;
3629 if (!pte_present(pteval))
3631 if (!pte_numa(pteval))
3633 if (addr >= vma->vm_end) {
3634 vma = find_vma(mm, addr);
3635 /* there's a pte present so there must be a vma */
3637 BUG_ON(addr < vma->vm_start);
3639 if (pte_numa(pteval)) {
3640 pteval = pte_mknonnuma(pteval);
3641 set_pte_at(mm, addr, pte, pteval);
3643 page = vm_normal_page(vma, addr, pteval);
3644 if (unlikely(!page))
3646 /* only check non-shared pages */
3647 if (unlikely(page_mapcount(page) != 1))
3651 * Note that the NUMA fault is later accounted to either
3652 * the node that is currently running or where the page is
3655 curr_nid = local_nid;
3656 target_nid = numa_migrate_prep(page, vma, addr,
3658 if (target_nid == -1) {
3663 /* Migrate to the requested node */
3664 pte_unmap_unlock(pte, ptl);
3665 migrated = migrate_misplaced_page(page, target_nid);
3667 curr_nid = target_nid;
3668 task_numa_fault(curr_nid, 1, migrated);
3670 pte = pte_offset_map_lock(mm, pmdp, addr, &ptl);
3672 pte_unmap_unlock(orig_pte, ptl);
3677 static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3678 unsigned long addr, pmd_t *pmdp)
3683 #endif /* CONFIG_NUMA_BALANCING */
3686 * These routines also need to handle stuff like marking pages dirty
3687 * and/or accessed for architectures that don't do it in hardware (most
3688 * RISC architectures). The early dirtying is also good on the i386.
3690 * There is also a hook called "update_mmu_cache()" that architectures
3691 * with external mmu caches can use to update those (ie the Sparc or
3692 * PowerPC hashed page tables that act as extended TLBs).
3694 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3695 * but allow concurrent faults), and pte mapped but not yet locked.
3696 * We return with mmap_sem still held, but pte unmapped and unlocked.
3698 int handle_pte_fault(struct mm_struct *mm,
3699 struct vm_area_struct *vma, unsigned long address,
3700 pte_t *pte, pmd_t *pmd, unsigned int flags)
3706 if (!pte_present(entry)) {
3707 if (pte_none(entry)) {
3709 if (likely(vma->vm_ops->fault))
3710 return do_linear_fault(mm, vma, address,
3711 pte, pmd, flags, entry);
3713 return do_anonymous_page(mm, vma, address,
3716 if (pte_file(entry))
3717 return do_nonlinear_fault(mm, vma, address,
3718 pte, pmd, flags, entry);
3719 return do_swap_page(mm, vma, address,
3720 pte, pmd, flags, entry);
3723 if (pte_numa(entry))
3724 return do_numa_page(mm, vma, address, entry, pte, pmd);
3726 ptl = pte_lockptr(mm, pmd);
3728 if (unlikely(!pte_same(*pte, entry)))
3730 if (flags & FAULT_FLAG_WRITE) {
3731 if (!pte_write(entry))
3732 return do_wp_page(mm, vma, address,
3733 pte, pmd, ptl, entry);
3734 entry = pte_mkdirty(entry);
3736 entry = pte_mkyoung(entry);
3737 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3738 update_mmu_cache(vma, address, pte);
3741 * This is needed only for protection faults but the arch code
3742 * is not yet telling us if this is a protection fault or not.
3743 * This still avoids useless tlb flushes for .text page faults
3746 if (flags & FAULT_FLAG_WRITE)
3747 flush_tlb_fix_spurious_fault(vma, address);
3750 pte_unmap_unlock(pte, ptl);
3755 * By the time we get here, we already hold the mm semaphore
3757 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3758 unsigned long address, unsigned int flags)
3765 __set_current_state(TASK_RUNNING);
3767 count_vm_event(PGFAULT);
3768 mem_cgroup_count_vm_event(mm, PGFAULT);
3770 /* do counter updates before entering really critical section. */
3771 check_sync_rss_stat(current);
3773 if (unlikely(is_vm_hugetlb_page(vma)))
3774 return hugetlb_fault(mm, vma, address, flags);
3777 pgd = pgd_offset(mm, address);
3778 pud = pud_alloc(mm, pgd, address);
3780 return VM_FAULT_OOM;
3781 pmd = pmd_alloc(mm, pud, address);
3783 return VM_FAULT_OOM;
3784 if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
3786 return do_huge_pmd_anonymous_page(mm, vma, address,
3789 pmd_t orig_pmd = *pmd;
3793 if (pmd_trans_huge(orig_pmd)) {
3794 unsigned int dirty = flags & FAULT_FLAG_WRITE;
3797 * If the pmd is splitting, return and retry the
3798 * the fault. Alternative: wait until the split
3799 * is done, and goto retry.
3801 if (pmd_trans_splitting(orig_pmd))
3804 if (pmd_numa(orig_pmd))
3805 return do_huge_pmd_numa_page(mm, vma, address,
3808 if (dirty && !pmd_write(orig_pmd)) {
3809 ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
3812 * If COW results in an oom, the huge pmd will
3813 * have been split, so retry the fault on the
3814 * pte for a smaller charge.
3816 if (unlikely(ret & VM_FAULT_OOM))
3820 huge_pmd_set_accessed(mm, vma, address, pmd,
3829 return do_pmd_numa_page(mm, vma, address, pmd);
3832 * Use __pte_alloc instead of pte_alloc_map, because we can't
3833 * run pte_offset_map on the pmd, if an huge pmd could
3834 * materialize from under us from a different thread.
3836 if (unlikely(pmd_none(*pmd)) &&
3837 unlikely(__pte_alloc(mm, vma, pmd, address)))
3838 return VM_FAULT_OOM;
3839 /* if an huge pmd materialized from under us just retry later */
3840 if (unlikely(pmd_trans_huge(*pmd)))
3843 * A regular pmd is established and it can't morph into a huge pmd
3844 * from under us anymore at this point because we hold the mmap_sem
3845 * read mode and khugepaged takes it in write mode. So now it's
3846 * safe to run pte_offset_map().
3848 pte = pte_offset_map(pmd, address);
3850 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3853 #ifndef __PAGETABLE_PUD_FOLDED
3855 * Allocate page upper directory.
3856 * We've already handled the fast-path in-line.
3858 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3860 pud_t *new = pud_alloc_one(mm, address);
3864 smp_wmb(); /* See comment in __pte_alloc */
3866 spin_lock(&mm->page_table_lock);
3867 if (pgd_present(*pgd)) /* Another has populated it */
3870 pgd_populate(mm, pgd, new);
3871 spin_unlock(&mm->page_table_lock);
3874 #endif /* __PAGETABLE_PUD_FOLDED */
3876 #ifndef __PAGETABLE_PMD_FOLDED
3878 * Allocate page middle directory.
3879 * We've already handled the fast-path in-line.
3881 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3883 pmd_t *new = pmd_alloc_one(mm, address);
3887 smp_wmb(); /* See comment in __pte_alloc */
3889 spin_lock(&mm->page_table_lock);
3890 #ifndef __ARCH_HAS_4LEVEL_HACK
3891 if (pud_present(*pud)) /* Another has populated it */
3894 pud_populate(mm, pud, new);
3896 if (pgd_present(*pud)) /* Another has populated it */
3899 pgd_populate(mm, pud, new);
3900 #endif /* __ARCH_HAS_4LEVEL_HACK */
3901 spin_unlock(&mm->page_table_lock);
3904 #endif /* __PAGETABLE_PMD_FOLDED */
3906 #if !defined(__HAVE_ARCH_GATE_AREA)
3908 #if defined(AT_SYSINFO_EHDR)
3909 static struct vm_area_struct gate_vma;
3911 static int __init gate_vma_init(void)
3913 gate_vma.vm_mm = NULL;
3914 gate_vma.vm_start = FIXADDR_USER_START;
3915 gate_vma.vm_end = FIXADDR_USER_END;
3916 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3917 gate_vma.vm_page_prot = __P101;
3921 __initcall(gate_vma_init);
3924 struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
3926 #ifdef AT_SYSINFO_EHDR
3933 int in_gate_area_no_mm(unsigned long addr)
3935 #ifdef AT_SYSINFO_EHDR
3936 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3942 #endif /* __HAVE_ARCH_GATE_AREA */
3944 static int __follow_pte(struct mm_struct *mm, unsigned long address,
3945 pte_t **ptepp, spinlock_t **ptlp)
3952 pgd = pgd_offset(mm, address);
3953 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3956 pud = pud_offset(pgd, address);
3957 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3960 pmd = pmd_offset(pud, address);
3961 VM_BUG_ON(pmd_trans_huge(*pmd));
3962 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3965 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3969 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3972 if (!pte_present(*ptep))
3977 pte_unmap_unlock(ptep, *ptlp);
3982 static inline int follow_pte(struct mm_struct *mm, unsigned long address,
3983 pte_t **ptepp, spinlock_t **ptlp)
3987 /* (void) is needed to make gcc happy */
3988 (void) __cond_lock(*ptlp,
3989 !(res = __follow_pte(mm, address, ptepp, ptlp)));
3994 * follow_pfn - look up PFN at a user virtual address
3995 * @vma: memory mapping
3996 * @address: user virtual address
3997 * @pfn: location to store found PFN
3999 * Only IO mappings and raw PFN mappings are allowed.
4001 * Returns zero and the pfn at @pfn on success, -ve otherwise.
4003 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
4010 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
4013 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
4016 *pfn = pte_pfn(*ptep);
4017 pte_unmap_unlock(ptep, ptl);
4020 EXPORT_SYMBOL(follow_pfn);
4022 #ifdef CONFIG_HAVE_IOREMAP_PROT
4023 int follow_phys(struct vm_area_struct *vma,
4024 unsigned long address, unsigned int flags,
4025 unsigned long *prot, resource_size_t *phys)
4031 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
4034 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
4038 if ((flags & FOLL_WRITE) && !pte_write(pte))
4041 *prot = pgprot_val(pte_pgprot(pte));
4042 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
4046 pte_unmap_unlock(ptep, ptl);
4051 int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
4052 void *buf, int len, int write)
4054 resource_size_t phys_addr;
4055 unsigned long prot = 0;
4056 void __iomem *maddr;
4057 int offset = addr & (PAGE_SIZE-1);
4059 if (follow_phys(vma, addr, write, &prot, &phys_addr))
4062 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
4064 memcpy_toio(maddr + offset, buf, len);
4066 memcpy_fromio(buf, maddr + offset, len);
4074 * Access another process' address space as given in mm. If non-NULL, use the
4075 * given task for page fault accounting.
4077 static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
4078 unsigned long addr, void *buf, int len, int write)
4080 struct vm_area_struct *vma;
4081 void *old_buf = buf;
4083 down_read(&mm->mmap_sem);
4084 /* ignore errors, just check how much was successfully transferred */
4086 int bytes, ret, offset;
4088 struct page *page = NULL;
4090 ret = get_user_pages(tsk, mm, addr, 1,
4091 write, 1, &page, &vma);
4094 * Check if this is a VM_IO | VM_PFNMAP VMA, which
4095 * we can access using slightly different code.
4097 #ifdef CONFIG_HAVE_IOREMAP_PROT
4098 vma = find_vma(mm, addr);
4099 if (!vma || vma->vm_start > addr)
4101 if (vma->vm_ops && vma->vm_ops->access)
4102 ret = vma->vm_ops->access(vma, addr, buf,
4110 offset = addr & (PAGE_SIZE-1);
4111 if (bytes > PAGE_SIZE-offset)
4112 bytes = PAGE_SIZE-offset;
4116 copy_to_user_page(vma, page, addr,
4117 maddr + offset, buf, bytes);
4118 set_page_dirty_lock(page);
4120 copy_from_user_page(vma, page, addr,
4121 buf, maddr + offset, bytes);
4124 page_cache_release(page);
4130 up_read(&mm->mmap_sem);
4132 return buf - old_buf;
4136 * access_remote_vm - access another process' address space
4137 * @mm: the mm_struct of the target address space
4138 * @addr: start address to access
4139 * @buf: source or destination buffer
4140 * @len: number of bytes to transfer
4141 * @write: whether the access is a write
4143 * The caller must hold a reference on @mm.
4145 int access_remote_vm(struct mm_struct *mm, unsigned long addr,
4146 void *buf, int len, int write)
4148 return __access_remote_vm(NULL, mm, addr, buf, len, write);
4152 * Access another process' address space.
4153 * Source/target buffer must be kernel space,
4154 * Do not walk the page table directly, use get_user_pages
4156 int access_process_vm(struct task_struct *tsk, unsigned long addr,
4157 void *buf, int len, int write)
4159 struct mm_struct *mm;
4162 mm = get_task_mm(tsk);
4166 ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
4173 * Print the name of a VMA.
4175 void print_vma_addr(char *prefix, unsigned long ip)
4177 struct mm_struct *mm = current->mm;
4178 struct vm_area_struct *vma;
4181 * Do not print if we are in atomic
4182 * contexts (in exception stacks, etc.):
4184 if (preempt_count())
4187 down_read(&mm->mmap_sem);
4188 vma = find_vma(mm, ip);
4189 if (vma && vma->vm_file) {
4190 struct file *f = vma->vm_file;
4191 char *buf = (char *)__get_free_page(GFP_KERNEL);
4195 p = d_path(&f->f_path, buf, PAGE_SIZE);
4198 printk("%s%s[%lx+%lx]", prefix, kbasename(p),
4200 vma->vm_end - vma->vm_start);
4201 free_page((unsigned long)buf);
4204 up_read(&mm->mmap_sem);
4207 #ifdef CONFIG_PROVE_LOCKING
4208 void might_fault(void)
4211 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4212 * holding the mmap_sem, this is safe because kernel memory doesn't
4213 * get paged out, therefore we'll never actually fault, and the
4214 * below annotations will generate false positives.
4216 if (segment_eq(get_fs(), KERNEL_DS))
4221 * it would be nicer only to annotate paths which are not under
4222 * pagefault_disable, however that requires a larger audit and
4223 * providing helpers like get_user_atomic.
4225 if (!in_atomic() && current->mm)
4226 might_lock_read(¤t->mm->mmap_sem);
4228 EXPORT_SYMBOL(might_fault);
4231 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4232 static void clear_gigantic_page(struct page *page,
4234 unsigned int pages_per_huge_page)
4237 struct page *p = page;
4240 for (i = 0; i < pages_per_huge_page;
4241 i++, p = mem_map_next(p, page, i)) {
4243 clear_user_highpage(p, addr + i * PAGE_SIZE);
4246 void clear_huge_page(struct page *page,
4247 unsigned long addr, unsigned int pages_per_huge_page)
4251 if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4252 clear_gigantic_page(page, addr, pages_per_huge_page);
4257 for (i = 0; i < pages_per_huge_page; i++) {
4259 clear_user_highpage(page + i, addr + i * PAGE_SIZE);
4263 static void copy_user_gigantic_page(struct page *dst, struct page *src,
4265 struct vm_area_struct *vma,
4266 unsigned int pages_per_huge_page)
4269 struct page *dst_base = dst;
4270 struct page *src_base = src;
4272 for (i = 0; i < pages_per_huge_page; ) {
4274 copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
4277 dst = mem_map_next(dst, dst_base, i);
4278 src = mem_map_next(src, src_base, i);
4282 void copy_user_huge_page(struct page *dst, struct page *src,
4283 unsigned long addr, struct vm_area_struct *vma,
4284 unsigned int pages_per_huge_page)
4288 if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4289 copy_user_gigantic_page(dst, src, addr, vma,
4290 pages_per_huge_page);
4295 for (i = 0; i < pages_per_huge_page; i++) {
4297 copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
4300 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */