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_CPUPID_NOT_IN_PAGE_FLAGS
73 #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
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
);
86 * A number of key systems in x86 including ioremap() rely on the assumption
87 * that high_memory defines the upper bound on direct map memory, then end
88 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
89 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
94 EXPORT_SYMBOL(high_memory
);
97 * Randomize the address space (stacks, mmaps, brk, etc.).
99 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
100 * as ancient (libc5 based) binaries can segfault. )
102 int randomize_va_space __read_mostly
=
103 #ifdef CONFIG_COMPAT_BRK
109 static int __init
disable_randmaps(char *s
)
111 randomize_va_space
= 0;
114 __setup("norandmaps", disable_randmaps
);
116 unsigned long zero_pfn __read_mostly
;
117 unsigned long highest_memmap_pfn __read_mostly
;
120 * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
122 static int __init
init_zero_pfn(void)
124 zero_pfn
= page_to_pfn(ZERO_PAGE(0));
127 core_initcall(init_zero_pfn
);
130 #if defined(SPLIT_RSS_COUNTING)
132 void sync_mm_rss(struct mm_struct
*mm
)
136 for (i
= 0; i
< NR_MM_COUNTERS
; i
++) {
137 if (current
->rss_stat
.count
[i
]) {
138 add_mm_counter(mm
, i
, current
->rss_stat
.count
[i
]);
139 current
->rss_stat
.count
[i
] = 0;
142 current
->rss_stat
.events
= 0;
145 static void add_mm_counter_fast(struct mm_struct
*mm
, int member
, int val
)
147 struct task_struct
*task
= current
;
149 if (likely(task
->mm
== mm
))
150 task
->rss_stat
.count
[member
] += val
;
152 add_mm_counter(mm
, member
, val
);
154 #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
155 #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
157 /* sync counter once per 64 page faults */
158 #define TASK_RSS_EVENTS_THRESH (64)
159 static void check_sync_rss_stat(struct task_struct
*task
)
161 if (unlikely(task
!= current
))
163 if (unlikely(task
->rss_stat
.events
++ > TASK_RSS_EVENTS_THRESH
))
164 sync_mm_rss(task
->mm
);
166 #else /* SPLIT_RSS_COUNTING */
168 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
169 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
171 static void check_sync_rss_stat(struct task_struct
*task
)
175 #endif /* SPLIT_RSS_COUNTING */
177 #ifdef HAVE_GENERIC_MMU_GATHER
179 static int tlb_next_batch(struct mmu_gather
*tlb
)
181 struct mmu_gather_batch
*batch
;
185 tlb
->active
= batch
->next
;
189 if (tlb
->batch_count
== MAX_GATHER_BATCH_COUNT
)
192 batch
= (void *)__get_free_pages(GFP_NOWAIT
| __GFP_NOWARN
, 0);
199 batch
->max
= MAX_GATHER_BATCH
;
201 tlb
->active
->next
= batch
;
208 * Called to initialize an (on-stack) mmu_gather structure for page-table
209 * tear-down from @mm. The @fullmm argument is used when @mm is without
210 * users and we're going to destroy the full address space (exit/execve).
212 void tlb_gather_mmu(struct mmu_gather
*tlb
, struct mm_struct
*mm
, unsigned long start
, unsigned long end
)
216 /* Is it from 0 to ~0? */
217 tlb
->fullmm
= !(start
| (end
+1));
218 tlb
->need_flush_all
= 0;
222 tlb
->local
.next
= NULL
;
224 tlb
->local
.max
= ARRAY_SIZE(tlb
->__pages
);
225 tlb
->active
= &tlb
->local
;
226 tlb
->batch_count
= 0;
228 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
233 void tlb_flush_mmu(struct mmu_gather
*tlb
)
235 struct mmu_gather_batch
*batch
;
237 if (!tlb
->need_flush
)
241 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
242 tlb_table_flush(tlb
);
245 for (batch
= &tlb
->local
; batch
; batch
= batch
->next
) {
246 free_pages_and_swap_cache(batch
->pages
, batch
->nr
);
249 tlb
->active
= &tlb
->local
;
253 * Called at the end of the shootdown operation to free up any resources
254 * that were required.
256 void tlb_finish_mmu(struct mmu_gather
*tlb
, unsigned long start
, unsigned long end
)
258 struct mmu_gather_batch
*batch
, *next
;
262 /* keep the page table cache within bounds */
265 for (batch
= tlb
->local
.next
; batch
; batch
= next
) {
267 free_pages((unsigned long)batch
, 0);
269 tlb
->local
.next
= NULL
;
273 * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
274 * handling the additional races in SMP caused by other CPUs caching valid
275 * mappings in their TLBs. Returns the number of free page slots left.
276 * When out of page slots we must call tlb_flush_mmu().
278 int __tlb_remove_page(struct mmu_gather
*tlb
, struct page
*page
)
280 struct mmu_gather_batch
*batch
;
282 VM_BUG_ON(!tlb
->need_flush
);
285 batch
->pages
[batch
->nr
++] = page
;
286 if (batch
->nr
== batch
->max
) {
287 if (!tlb_next_batch(tlb
))
291 VM_BUG_ON(batch
->nr
> batch
->max
);
293 return batch
->max
- batch
->nr
;
296 #endif /* HAVE_GENERIC_MMU_GATHER */
298 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
301 * See the comment near struct mmu_table_batch.
304 static void tlb_remove_table_smp_sync(void *arg
)
306 /* Simply deliver the interrupt */
309 static void tlb_remove_table_one(void *table
)
312 * This isn't an RCU grace period and hence the page-tables cannot be
313 * assumed to be actually RCU-freed.
315 * It is however sufficient for software page-table walkers that rely on
316 * IRQ disabling. See the comment near struct mmu_table_batch.
318 smp_call_function(tlb_remove_table_smp_sync
, NULL
, 1);
319 __tlb_remove_table(table
);
322 static void tlb_remove_table_rcu(struct rcu_head
*head
)
324 struct mmu_table_batch
*batch
;
327 batch
= container_of(head
, struct mmu_table_batch
, rcu
);
329 for (i
= 0; i
< batch
->nr
; i
++)
330 __tlb_remove_table(batch
->tables
[i
]);
332 free_page((unsigned long)batch
);
335 void tlb_table_flush(struct mmu_gather
*tlb
)
337 struct mmu_table_batch
**batch
= &tlb
->batch
;
340 call_rcu_sched(&(*batch
)->rcu
, tlb_remove_table_rcu
);
345 void tlb_remove_table(struct mmu_gather
*tlb
, void *table
)
347 struct mmu_table_batch
**batch
= &tlb
->batch
;
352 * When there's less then two users of this mm there cannot be a
353 * concurrent page-table walk.
355 if (atomic_read(&tlb
->mm
->mm_users
) < 2) {
356 __tlb_remove_table(table
);
360 if (*batch
== NULL
) {
361 *batch
= (struct mmu_table_batch
*)__get_free_page(GFP_NOWAIT
| __GFP_NOWARN
);
362 if (*batch
== NULL
) {
363 tlb_remove_table_one(table
);
368 (*batch
)->tables
[(*batch
)->nr
++] = table
;
369 if ((*batch
)->nr
== MAX_TABLE_BATCH
)
370 tlb_table_flush(tlb
);
373 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
376 * Note: this doesn't free the actual pages themselves. That
377 * has been handled earlier when unmapping all the memory regions.
379 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
,
382 pgtable_t token
= pmd_pgtable(*pmd
);
384 pte_free_tlb(tlb
, token
, addr
);
385 atomic_long_dec(&tlb
->mm
->nr_ptes
);
388 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
389 unsigned long addr
, unsigned long end
,
390 unsigned long floor
, unsigned long ceiling
)
397 pmd
= pmd_offset(pud
, addr
);
399 next
= pmd_addr_end(addr
, end
);
400 if (pmd_none_or_clear_bad(pmd
))
402 free_pte_range(tlb
, pmd
, addr
);
403 } while (pmd
++, addr
= next
, addr
!= end
);
413 if (end
- 1 > ceiling
- 1)
416 pmd
= pmd_offset(pud
, start
);
418 pmd_free_tlb(tlb
, pmd
, start
);
421 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
422 unsigned long addr
, unsigned long end
,
423 unsigned long floor
, unsigned long ceiling
)
430 pud
= pud_offset(pgd
, addr
);
432 next
= pud_addr_end(addr
, end
);
433 if (pud_none_or_clear_bad(pud
))
435 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
436 } while (pud
++, addr
= next
, addr
!= end
);
442 ceiling
&= PGDIR_MASK
;
446 if (end
- 1 > ceiling
- 1)
449 pud
= pud_offset(pgd
, start
);
451 pud_free_tlb(tlb
, pud
, start
);
455 * This function frees user-level page tables of a process.
457 void free_pgd_range(struct mmu_gather
*tlb
,
458 unsigned long addr
, unsigned long end
,
459 unsigned long floor
, unsigned long ceiling
)
465 * The next few lines have given us lots of grief...
467 * Why are we testing PMD* at this top level? Because often
468 * there will be no work to do at all, and we'd prefer not to
469 * go all the way down to the bottom just to discover that.
471 * Why all these "- 1"s? Because 0 represents both the bottom
472 * of the address space and the top of it (using -1 for the
473 * top wouldn't help much: the masks would do the wrong thing).
474 * The rule is that addr 0 and floor 0 refer to the bottom of
475 * the address space, but end 0 and ceiling 0 refer to the top
476 * Comparisons need to use "end - 1" and "ceiling - 1" (though
477 * that end 0 case should be mythical).
479 * Wherever addr is brought up or ceiling brought down, we must
480 * be careful to reject "the opposite 0" before it confuses the
481 * subsequent tests. But what about where end is brought down
482 * by PMD_SIZE below? no, end can't go down to 0 there.
484 * Whereas we round start (addr) and ceiling down, by different
485 * masks at different levels, in order to test whether a table
486 * now has no other vmas using it, so can be freed, we don't
487 * bother to round floor or end up - the tests don't need that.
501 if (end
- 1 > ceiling
- 1)
506 pgd
= pgd_offset(tlb
->mm
, addr
);
508 next
= pgd_addr_end(addr
, end
);
509 if (pgd_none_or_clear_bad(pgd
))
511 free_pud_range(tlb
, pgd
, addr
, next
, floor
, ceiling
);
512 } while (pgd
++, addr
= next
, addr
!= end
);
515 void free_pgtables(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
516 unsigned long floor
, unsigned long ceiling
)
519 struct vm_area_struct
*next
= vma
->vm_next
;
520 unsigned long addr
= vma
->vm_start
;
523 * Hide vma from rmap and truncate_pagecache before freeing
526 unlink_anon_vmas(vma
);
527 unlink_file_vma(vma
);
529 if (is_vm_hugetlb_page(vma
)) {
530 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
531 floor
, next
? next
->vm_start
: ceiling
);
534 * Optimization: gather nearby vmas into one call down
536 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
537 && !is_vm_hugetlb_page(next
)) {
540 unlink_anon_vmas(vma
);
541 unlink_file_vma(vma
);
543 free_pgd_range(tlb
, addr
, vma
->vm_end
,
544 floor
, next
? next
->vm_start
: ceiling
);
550 int __pte_alloc(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
551 pmd_t
*pmd
, unsigned long address
)
554 pgtable_t
new = pte_alloc_one(mm
, address
);
555 int wait_split_huge_page
;
560 * Ensure all pte setup (eg. pte page lock and page clearing) are
561 * visible before the pte is made visible to other CPUs by being
562 * put into page tables.
564 * The other side of the story is the pointer chasing in the page
565 * table walking code (when walking the page table without locking;
566 * ie. most of the time). Fortunately, these data accesses consist
567 * of a chain of data-dependent loads, meaning most CPUs (alpha
568 * being the notable exception) will already guarantee loads are
569 * seen in-order. See the alpha page table accessors for the
570 * smp_read_barrier_depends() barriers in page table walking code.
572 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
574 ptl
= pmd_lock(mm
, pmd
);
575 wait_split_huge_page
= 0;
576 if (likely(pmd_none(*pmd
))) { /* Has another populated it ? */
577 atomic_long_inc(&mm
->nr_ptes
);
578 pmd_populate(mm
, pmd
, new);
580 } else if (unlikely(pmd_trans_splitting(*pmd
)))
581 wait_split_huge_page
= 1;
585 if (wait_split_huge_page
)
586 wait_split_huge_page(vma
->anon_vma
, pmd
);
590 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
592 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
596 smp_wmb(); /* See comment in __pte_alloc */
598 spin_lock(&init_mm
.page_table_lock
);
599 if (likely(pmd_none(*pmd
))) { /* Has another populated it ? */
600 pmd_populate_kernel(&init_mm
, pmd
, new);
603 VM_BUG_ON(pmd_trans_splitting(*pmd
));
604 spin_unlock(&init_mm
.page_table_lock
);
606 pte_free_kernel(&init_mm
, new);
610 static inline void init_rss_vec(int *rss
)
612 memset(rss
, 0, sizeof(int) * NR_MM_COUNTERS
);
615 static inline void add_mm_rss_vec(struct mm_struct
*mm
, int *rss
)
619 if (current
->mm
== mm
)
621 for (i
= 0; i
< NR_MM_COUNTERS
; i
++)
623 add_mm_counter(mm
, i
, rss
[i
]);
627 * This function is called to print an error when a bad pte
628 * is found. For example, we might have a PFN-mapped pte in
629 * a region that doesn't allow it.
631 * The calling function must still handle the error.
633 static void print_bad_pte(struct vm_area_struct
*vma
, unsigned long addr
,
634 pte_t pte
, struct page
*page
)
636 pgd_t
*pgd
= pgd_offset(vma
->vm_mm
, addr
);
637 pud_t
*pud
= pud_offset(pgd
, addr
);
638 pmd_t
*pmd
= pmd_offset(pud
, addr
);
639 struct address_space
*mapping
;
641 static unsigned long resume
;
642 static unsigned long nr_shown
;
643 static unsigned long nr_unshown
;
646 * Allow a burst of 60 reports, then keep quiet for that minute;
647 * or allow a steady drip of one report per second.
649 if (nr_shown
== 60) {
650 if (time_before(jiffies
, resume
)) {
656 "BUG: Bad page map: %lu messages suppressed\n",
663 resume
= jiffies
+ 60 * HZ
;
665 mapping
= vma
->vm_file
? vma
->vm_file
->f_mapping
: NULL
;
666 index
= linear_page_index(vma
, addr
);
669 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
671 (long long)pte_val(pte
), (long long)pmd_val(*pmd
));
675 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
676 (void *)addr
, vma
->vm_flags
, vma
->anon_vma
, mapping
, index
);
678 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
681 printk(KERN_ALERT
"vma->vm_ops->fault: %pSR\n",
684 printk(KERN_ALERT
"vma->vm_file->f_op->mmap: %pSR\n",
685 vma
->vm_file
->f_op
->mmap
);
687 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
690 static inline bool is_cow_mapping(vm_flags_t flags
)
692 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
696 * vm_normal_page -- This function gets the "struct page" associated with a pte.
698 * "Special" mappings do not wish to be associated with a "struct page" (either
699 * it doesn't exist, or it exists but they don't want to touch it). In this
700 * case, NULL is returned here. "Normal" mappings do have a struct page.
702 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
703 * pte bit, in which case this function is trivial. Secondly, an architecture
704 * may not have a spare pte bit, which requires a more complicated scheme,
707 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
708 * special mapping (even if there are underlying and valid "struct pages").
709 * COWed pages of a VM_PFNMAP are always normal.
711 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
712 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
713 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
714 * mapping will always honor the rule
716 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
718 * And for normal mappings this is false.
720 * This restricts such mappings to be a linear translation from virtual address
721 * to pfn. To get around this restriction, we allow arbitrary mappings so long
722 * as the vma is not a COW mapping; in that case, we know that all ptes are
723 * special (because none can have been COWed).
726 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
728 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
729 * page" backing, however the difference is that _all_ pages with a struct
730 * page (that is, those where pfn_valid is true) are refcounted and considered
731 * normal pages by the VM. The disadvantage is that pages are refcounted
732 * (which can be slower and simply not an option for some PFNMAP users). The
733 * advantage is that we don't have to follow the strict linearity rule of
734 * PFNMAP mappings in order to support COWable mappings.
737 #ifdef __HAVE_ARCH_PTE_SPECIAL
738 # define HAVE_PTE_SPECIAL 1
740 # define HAVE_PTE_SPECIAL 0
742 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
,
745 unsigned long pfn
= pte_pfn(pte
);
747 if (HAVE_PTE_SPECIAL
) {
748 if (likely(!pte_special(pte
)))
750 if (vma
->vm_flags
& (VM_PFNMAP
| VM_MIXEDMAP
))
752 if (!is_zero_pfn(pfn
))
753 print_bad_pte(vma
, addr
, pte
, NULL
);
757 /* !HAVE_PTE_SPECIAL case follows: */
759 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
760 if (vma
->vm_flags
& VM_MIXEDMAP
) {
766 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
767 if (pfn
== vma
->vm_pgoff
+ off
)
769 if (!is_cow_mapping(vma
->vm_flags
))
774 if (is_zero_pfn(pfn
))
777 if (unlikely(pfn
> highest_memmap_pfn
)) {
778 print_bad_pte(vma
, addr
, pte
, NULL
);
783 * NOTE! We still have PageReserved() pages in the page tables.
784 * eg. VDSO mappings can cause them to exist.
787 return pfn_to_page(pfn
);
791 * copy one vm_area from one task to the other. Assumes the page tables
792 * already present in the new task to be cleared in the whole range
793 * covered by this vma.
796 static inline unsigned long
797 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
798 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
799 unsigned long addr
, int *rss
)
801 unsigned long vm_flags
= vma
->vm_flags
;
802 pte_t pte
= *src_pte
;
805 /* pte contains position in swap or file, so copy. */
806 if (unlikely(!pte_present(pte
))) {
807 if (!pte_file(pte
)) {
808 swp_entry_t entry
= pte_to_swp_entry(pte
);
810 if (swap_duplicate(entry
) < 0)
813 /* make sure dst_mm is on swapoff's mmlist. */
814 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
815 spin_lock(&mmlist_lock
);
816 if (list_empty(&dst_mm
->mmlist
))
817 list_add(&dst_mm
->mmlist
,
819 spin_unlock(&mmlist_lock
);
821 if (likely(!non_swap_entry(entry
)))
823 else if (is_migration_entry(entry
)) {
824 page
= migration_entry_to_page(entry
);
831 if (is_write_migration_entry(entry
) &&
832 is_cow_mapping(vm_flags
)) {
834 * COW mappings require pages in both
835 * parent and child to be set to read.
837 make_migration_entry_read(&entry
);
838 pte
= swp_entry_to_pte(entry
);
839 if (pte_swp_soft_dirty(*src_pte
))
840 pte
= pte_swp_mksoft_dirty(pte
);
841 set_pte_at(src_mm
, addr
, src_pte
, pte
);
849 * If it's a COW mapping, write protect it both
850 * in the parent and the child
852 if (is_cow_mapping(vm_flags
)) {
853 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
854 pte
= pte_wrprotect(pte
);
858 * If it's a shared mapping, mark it clean in
861 if (vm_flags
& VM_SHARED
)
862 pte
= pte_mkclean(pte
);
863 pte
= pte_mkold(pte
);
865 page
= vm_normal_page(vma
, addr
, pte
);
876 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
880 int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
881 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
882 unsigned long addr
, unsigned long end
)
884 pte_t
*orig_src_pte
, *orig_dst_pte
;
885 pte_t
*src_pte
, *dst_pte
;
886 spinlock_t
*src_ptl
, *dst_ptl
;
888 int rss
[NR_MM_COUNTERS
];
889 swp_entry_t entry
= (swp_entry_t
){0};
894 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
897 src_pte
= pte_offset_map(src_pmd
, addr
);
898 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
899 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
900 orig_src_pte
= src_pte
;
901 orig_dst_pte
= dst_pte
;
902 arch_enter_lazy_mmu_mode();
906 * We are holding two locks at this point - either of them
907 * could generate latencies in another task on another CPU.
909 if (progress
>= 32) {
911 if (need_resched() ||
912 spin_needbreak(src_ptl
) || spin_needbreak(dst_ptl
))
915 if (pte_none(*src_pte
)) {
919 entry
.val
= copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
,
924 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
926 arch_leave_lazy_mmu_mode();
927 spin_unlock(src_ptl
);
928 pte_unmap(orig_src_pte
);
929 add_mm_rss_vec(dst_mm
, rss
);
930 pte_unmap_unlock(orig_dst_pte
, dst_ptl
);
934 if (add_swap_count_continuation(entry
, GFP_KERNEL
) < 0)
943 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
944 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
945 unsigned long addr
, unsigned long end
)
947 pmd_t
*src_pmd
, *dst_pmd
;
950 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
953 src_pmd
= pmd_offset(src_pud
, addr
);
955 next
= pmd_addr_end(addr
, end
);
956 if (pmd_trans_huge(*src_pmd
)) {
958 VM_BUG_ON(next
-addr
!= HPAGE_PMD_SIZE
);
959 err
= copy_huge_pmd(dst_mm
, src_mm
,
960 dst_pmd
, src_pmd
, addr
, vma
);
967 if (pmd_none_or_clear_bad(src_pmd
))
969 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
972 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
976 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
977 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
978 unsigned long addr
, unsigned long end
)
980 pud_t
*src_pud
, *dst_pud
;
983 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
986 src_pud
= pud_offset(src_pgd
, addr
);
988 next
= pud_addr_end(addr
, end
);
989 if (pud_none_or_clear_bad(src_pud
))
991 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
994 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
998 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
999 struct vm_area_struct
*vma
)
1001 pgd_t
*src_pgd
, *dst_pgd
;
1003 unsigned long addr
= vma
->vm_start
;
1004 unsigned long end
= vma
->vm_end
;
1005 unsigned long mmun_start
; /* For mmu_notifiers */
1006 unsigned long mmun_end
; /* For mmu_notifiers */
1011 * Don't copy ptes where a page fault will fill them correctly.
1012 * Fork becomes much lighter when there are big shared or private
1013 * readonly mappings. The tradeoff is that copy_page_range is more
1014 * efficient than faulting.
1016 if (!(vma
->vm_flags
& (VM_HUGETLB
| VM_NONLINEAR
|
1017 VM_PFNMAP
| VM_MIXEDMAP
))) {
1022 if (is_vm_hugetlb_page(vma
))
1023 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
1025 if (unlikely(vma
->vm_flags
& VM_PFNMAP
)) {
1027 * We do not free on error cases below as remove_vma
1028 * gets called on error from higher level routine
1030 ret
= track_pfn_copy(vma
);
1036 * We need to invalidate the secondary MMU mappings only when
1037 * there could be a permission downgrade on the ptes of the
1038 * parent mm. And a permission downgrade will only happen if
1039 * is_cow_mapping() returns true.
1041 is_cow
= is_cow_mapping(vma
->vm_flags
);
1045 mmu_notifier_invalidate_range_start(src_mm
, mmun_start
,
1049 dst_pgd
= pgd_offset(dst_mm
, addr
);
1050 src_pgd
= pgd_offset(src_mm
, addr
);
1052 next
= pgd_addr_end(addr
, end
);
1053 if (pgd_none_or_clear_bad(src_pgd
))
1055 if (unlikely(copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
1056 vma
, addr
, next
))) {
1060 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
1063 mmu_notifier_invalidate_range_end(src_mm
, mmun_start
, mmun_end
);
1067 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
1068 struct vm_area_struct
*vma
, pmd_t
*pmd
,
1069 unsigned long addr
, unsigned long end
,
1070 struct zap_details
*details
)
1072 struct mm_struct
*mm
= tlb
->mm
;
1073 int force_flush
= 0;
1074 int rss
[NR_MM_COUNTERS
];
1081 start_pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
1083 arch_enter_lazy_mmu_mode();
1086 if (pte_none(ptent
)) {
1090 if (pte_present(ptent
)) {
1093 page
= vm_normal_page(vma
, addr
, ptent
);
1094 if (unlikely(details
) && page
) {
1096 * unmap_shared_mapping_pages() wants to
1097 * invalidate cache without truncating:
1098 * unmap shared but keep private pages.
1100 if (details
->check_mapping
&&
1101 details
->check_mapping
!= page
->mapping
)
1104 * Each page->index must be checked when
1105 * invalidating or truncating nonlinear.
1107 if (details
->nonlinear_vma
&&
1108 (page
->index
< details
->first_index
||
1109 page
->index
> details
->last_index
))
1112 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
1114 tlb_remove_tlb_entry(tlb
, pte
, addr
);
1115 if (unlikely(!page
))
1117 if (unlikely(details
) && details
->nonlinear_vma
1118 && linear_page_index(details
->nonlinear_vma
,
1119 addr
) != page
->index
) {
1120 pte_t ptfile
= pgoff_to_pte(page
->index
);
1121 if (pte_soft_dirty(ptent
))
1122 pte_file_mksoft_dirty(ptfile
);
1123 set_pte_at(mm
, addr
, pte
, ptfile
);
1126 rss
[MM_ANONPAGES
]--;
1128 if (pte_dirty(ptent
))
1129 set_page_dirty(page
);
1130 if (pte_young(ptent
) &&
1131 likely(!(vma
->vm_flags
& VM_SEQ_READ
)))
1132 mark_page_accessed(page
);
1133 rss
[MM_FILEPAGES
]--;
1135 page_remove_rmap(page
);
1136 if (unlikely(page_mapcount(page
) < 0))
1137 print_bad_pte(vma
, addr
, ptent
, page
);
1138 force_flush
= !__tlb_remove_page(tlb
, page
);
1144 * If details->check_mapping, we leave swap entries;
1145 * if details->nonlinear_vma, we leave file entries.
1147 if (unlikely(details
))
1149 if (pte_file(ptent
)) {
1150 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
)))
1151 print_bad_pte(vma
, addr
, ptent
, NULL
);
1153 swp_entry_t entry
= pte_to_swp_entry(ptent
);
1155 if (!non_swap_entry(entry
))
1157 else if (is_migration_entry(entry
)) {
1160 page
= migration_entry_to_page(entry
);
1163 rss
[MM_ANONPAGES
]--;
1165 rss
[MM_FILEPAGES
]--;
1167 if (unlikely(!free_swap_and_cache(entry
)))
1168 print_bad_pte(vma
, addr
, ptent
, NULL
);
1170 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
1171 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1173 add_mm_rss_vec(mm
, rss
);
1174 arch_leave_lazy_mmu_mode();
1175 pte_unmap_unlock(start_pte
, ptl
);
1178 * mmu_gather ran out of room to batch pages, we break out of
1179 * the PTE lock to avoid doing the potential expensive TLB invalidate
1180 * and page-free while holding it.
1183 unsigned long old_end
;
1188 * Flush the TLB just for the previous segment,
1189 * then update the range to be the remaining
1207 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
1208 struct vm_area_struct
*vma
, pud_t
*pud
,
1209 unsigned long addr
, unsigned long end
,
1210 struct zap_details
*details
)
1215 pmd
= pmd_offset(pud
, addr
);
1217 next
= pmd_addr_end(addr
, end
);
1218 if (pmd_trans_huge(*pmd
)) {
1219 if (next
- addr
!= HPAGE_PMD_SIZE
) {
1220 #ifdef CONFIG_DEBUG_VM
1221 if (!rwsem_is_locked(&tlb
->mm
->mmap_sem
)) {
1222 pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n",
1223 __func__
, addr
, end
,
1229 split_huge_page_pmd(vma
, addr
, pmd
);
1230 } else if (zap_huge_pmd(tlb
, vma
, pmd
, addr
))
1235 * Here there can be other concurrent MADV_DONTNEED or
1236 * trans huge page faults running, and if the pmd is
1237 * none or trans huge it can change under us. This is
1238 * because MADV_DONTNEED holds the mmap_sem in read
1241 if (pmd_none_or_trans_huge_or_clear_bad(pmd
))
1243 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
, details
);
1246 } while (pmd
++, addr
= next
, addr
!= end
);
1251 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
1252 struct vm_area_struct
*vma
, pgd_t
*pgd
,
1253 unsigned long addr
, unsigned long end
,
1254 struct zap_details
*details
)
1259 pud
= pud_offset(pgd
, addr
);
1261 next
= pud_addr_end(addr
, end
);
1262 if (pud_none_or_clear_bad(pud
))
1264 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
, details
);
1265 } while (pud
++, addr
= next
, addr
!= end
);
1270 static void unmap_page_range(struct mmu_gather
*tlb
,
1271 struct vm_area_struct
*vma
,
1272 unsigned long addr
, unsigned long end
,
1273 struct zap_details
*details
)
1278 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
1281 BUG_ON(addr
>= end
);
1282 mem_cgroup_uncharge_start();
1283 tlb_start_vma(tlb
, vma
);
1284 pgd
= pgd_offset(vma
->vm_mm
, addr
);
1286 next
= pgd_addr_end(addr
, end
);
1287 if (pgd_none_or_clear_bad(pgd
))
1289 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
, details
);
1290 } while (pgd
++, addr
= next
, addr
!= end
);
1291 tlb_end_vma(tlb
, vma
);
1292 mem_cgroup_uncharge_end();
1296 static void unmap_single_vma(struct mmu_gather
*tlb
,
1297 struct vm_area_struct
*vma
, unsigned long start_addr
,
1298 unsigned long end_addr
,
1299 struct zap_details
*details
)
1301 unsigned long start
= max(vma
->vm_start
, start_addr
);
1304 if (start
>= vma
->vm_end
)
1306 end
= min(vma
->vm_end
, end_addr
);
1307 if (end
<= vma
->vm_start
)
1311 uprobe_munmap(vma
, start
, end
);
1313 if (unlikely(vma
->vm_flags
& VM_PFNMAP
))
1314 untrack_pfn(vma
, 0, 0);
1317 if (unlikely(is_vm_hugetlb_page(vma
))) {
1319 * It is undesirable to test vma->vm_file as it
1320 * should be non-null for valid hugetlb area.
1321 * However, vm_file will be NULL in the error
1322 * cleanup path of do_mmap_pgoff. When
1323 * hugetlbfs ->mmap method fails,
1324 * do_mmap_pgoff() nullifies vma->vm_file
1325 * before calling this function to clean up.
1326 * Since no pte has actually been setup, it is
1327 * safe to do nothing in this case.
1330 mutex_lock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
1331 __unmap_hugepage_range_final(tlb
, vma
, start
, end
, NULL
);
1332 mutex_unlock(&vma
->vm_file
->f_mapping
->i_mmap_mutex
);
1335 unmap_page_range(tlb
, vma
, start
, end
, details
);
1340 * unmap_vmas - unmap a range of memory covered by a list of vma's
1341 * @tlb: address of the caller's struct mmu_gather
1342 * @vma: the starting vma
1343 * @start_addr: virtual address at which to start unmapping
1344 * @end_addr: virtual address at which to end unmapping
1346 * Unmap all pages in the vma list.
1348 * Only addresses between `start' and `end' will be unmapped.
1350 * The VMA list must be sorted in ascending virtual address order.
1352 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1353 * range after unmap_vmas() returns. So the only responsibility here is to
1354 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1355 * drops the lock and schedules.
1357 void unmap_vmas(struct mmu_gather
*tlb
,
1358 struct vm_area_struct
*vma
, unsigned long start_addr
,
1359 unsigned long end_addr
)
1361 struct mm_struct
*mm
= vma
->vm_mm
;
1363 mmu_notifier_invalidate_range_start(mm
, start_addr
, end_addr
);
1364 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
)
1365 unmap_single_vma(tlb
, vma
, start_addr
, end_addr
, NULL
);
1366 mmu_notifier_invalidate_range_end(mm
, start_addr
, end_addr
);
1370 * zap_page_range - remove user pages in a given range
1371 * @vma: vm_area_struct holding the applicable pages
1372 * @start: starting address of pages to zap
1373 * @size: number of bytes to zap
1374 * @details: details of nonlinear truncation or shared cache invalidation
1376 * Caller must protect the VMA list
1378 void zap_page_range(struct vm_area_struct
*vma
, unsigned long start
,
1379 unsigned long size
, struct zap_details
*details
)
1381 struct mm_struct
*mm
= vma
->vm_mm
;
1382 struct mmu_gather tlb
;
1383 unsigned long end
= start
+ size
;
1386 tlb_gather_mmu(&tlb
, mm
, start
, end
);
1387 update_hiwater_rss(mm
);
1388 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1389 for ( ; vma
&& vma
->vm_start
< end
; vma
= vma
->vm_next
)
1390 unmap_single_vma(&tlb
, vma
, start
, end
, details
);
1391 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1392 tlb_finish_mmu(&tlb
, start
, end
);
1396 * zap_page_range_single - remove user pages in a given range
1397 * @vma: vm_area_struct holding the applicable pages
1398 * @address: starting address of pages to zap
1399 * @size: number of bytes to zap
1400 * @details: details of nonlinear truncation or shared cache invalidation
1402 * The range must fit into one VMA.
1404 static void zap_page_range_single(struct vm_area_struct
*vma
, unsigned long address
,
1405 unsigned long size
, struct zap_details
*details
)
1407 struct mm_struct
*mm
= vma
->vm_mm
;
1408 struct mmu_gather tlb
;
1409 unsigned long end
= address
+ size
;
1412 tlb_gather_mmu(&tlb
, mm
, address
, end
);
1413 update_hiwater_rss(mm
);
1414 mmu_notifier_invalidate_range_start(mm
, address
, end
);
1415 unmap_single_vma(&tlb
, vma
, address
, end
, details
);
1416 mmu_notifier_invalidate_range_end(mm
, address
, end
);
1417 tlb_finish_mmu(&tlb
, address
, end
);
1421 * zap_vma_ptes - remove ptes mapping the vma
1422 * @vma: vm_area_struct holding ptes to be zapped
1423 * @address: starting address of pages to zap
1424 * @size: number of bytes to zap
1426 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1428 * The entire address range must be fully contained within the vma.
1430 * Returns 0 if successful.
1432 int zap_vma_ptes(struct vm_area_struct
*vma
, unsigned long address
,
1435 if (address
< vma
->vm_start
|| address
+ size
> vma
->vm_end
||
1436 !(vma
->vm_flags
& VM_PFNMAP
))
1438 zap_page_range_single(vma
, address
, size
, NULL
);
1441 EXPORT_SYMBOL_GPL(zap_vma_ptes
);
1444 * follow_page_mask - look up a page descriptor from a user-virtual address
1445 * @vma: vm_area_struct mapping @address
1446 * @address: virtual address to look up
1447 * @flags: flags modifying lookup behaviour
1448 * @page_mask: on output, *page_mask is set according to the size of the page
1450 * @flags can have FOLL_ flags set, defined in <linux/mm.h>
1452 * Returns the mapped (struct page *), %NULL if no mapping exists, or
1453 * an error pointer if there is a mapping to something not represented
1454 * by a page descriptor (see also vm_normal_page()).
1456 struct page
*follow_page_mask(struct vm_area_struct
*vma
,
1457 unsigned long address
, unsigned int flags
,
1458 unsigned int *page_mask
)
1466 struct mm_struct
*mm
= vma
->vm_mm
;
1470 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
1471 if (!IS_ERR(page
)) {
1472 BUG_ON(flags
& FOLL_GET
);
1477 pgd
= pgd_offset(mm
, address
);
1478 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
1481 pud
= pud_offset(pgd
, address
);
1484 if (pud_huge(*pud
) && vma
->vm_flags
& VM_HUGETLB
) {
1485 if (flags
& FOLL_GET
)
1487 page
= follow_huge_pud(mm
, address
, pud
, flags
& FOLL_WRITE
);
1490 if (unlikely(pud_bad(*pud
)))
1493 pmd
= pmd_offset(pud
, address
);
1496 if (pmd_huge(*pmd
) && vma
->vm_flags
& VM_HUGETLB
) {
1497 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
1498 if (flags
& FOLL_GET
) {
1500 * Refcount on tail pages are not well-defined and
1501 * shouldn't be taken. The caller should handle a NULL
1502 * return when trying to follow tail pages.
1513 if ((flags
& FOLL_NUMA
) && pmd_numa(*pmd
))
1515 if (pmd_trans_huge(*pmd
)) {
1516 if (flags
& FOLL_SPLIT
) {
1517 split_huge_page_pmd(vma
, address
, pmd
);
1518 goto split_fallthrough
;
1520 ptl
= pmd_lock(mm
, pmd
);
1521 if (likely(pmd_trans_huge(*pmd
))) {
1522 if (unlikely(pmd_trans_splitting(*pmd
))) {
1524 wait_split_huge_page(vma
->anon_vma
, pmd
);
1526 page
= follow_trans_huge_pmd(vma
, address
,
1529 *page_mask
= HPAGE_PMD_NR
- 1;
1537 if (unlikely(pmd_bad(*pmd
)))
1540 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1543 if (!pte_present(pte
)) {
1546 * KSM's break_ksm() relies upon recognizing a ksm page
1547 * even while it is being migrated, so for that case we
1548 * need migration_entry_wait().
1550 if (likely(!(flags
& FOLL_MIGRATION
)))
1552 if (pte_none(pte
) || pte_file(pte
))
1554 entry
= pte_to_swp_entry(pte
);
1555 if (!is_migration_entry(entry
))
1557 pte_unmap_unlock(ptep
, ptl
);
1558 migration_entry_wait(mm
, pmd
, address
);
1559 goto split_fallthrough
;
1561 if ((flags
& FOLL_NUMA
) && pte_numa(pte
))
1563 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
1566 page
= vm_normal_page(vma
, address
, pte
);
1567 if (unlikely(!page
)) {
1568 if ((flags
& FOLL_DUMP
) ||
1569 !is_zero_pfn(pte_pfn(pte
)))
1571 page
= pte_page(pte
);
1574 if (flags
& FOLL_GET
)
1575 get_page_foll(page
);
1576 if (flags
& FOLL_TOUCH
) {
1577 if ((flags
& FOLL_WRITE
) &&
1578 !pte_dirty(pte
) && !PageDirty(page
))
1579 set_page_dirty(page
);
1581 * pte_mkyoung() would be more correct here, but atomic care
1582 * is needed to avoid losing the dirty bit: it is easier to use
1583 * mark_page_accessed().
1585 mark_page_accessed(page
);
1587 if ((flags
& FOLL_MLOCK
) && (vma
->vm_flags
& VM_LOCKED
)) {
1589 * The preliminary mapping check is mainly to avoid the
1590 * pointless overhead of lock_page on the ZERO_PAGE
1591 * which might bounce very badly if there is contention.
1593 * If the page is already locked, we don't need to
1594 * handle it now - vmscan will handle it later if and
1595 * when it attempts to reclaim the page.
1597 if (page
->mapping
&& trylock_page(page
)) {
1598 lru_add_drain(); /* push cached pages to LRU */
1600 * Because we lock page here, and migration is
1601 * blocked by the pte's page reference, and we
1602 * know the page is still mapped, we don't even
1603 * need to check for file-cache page truncation.
1605 mlock_vma_page(page
);
1610 pte_unmap_unlock(ptep
, ptl
);
1615 pte_unmap_unlock(ptep
, ptl
);
1616 return ERR_PTR(-EFAULT
);
1619 pte_unmap_unlock(ptep
, ptl
);
1625 * When core dumping an enormous anonymous area that nobody
1626 * has touched so far, we don't want to allocate unnecessary pages or
1627 * page tables. Return error instead of NULL to skip handle_mm_fault,
1628 * then get_dump_page() will return NULL to leave a hole in the dump.
1629 * But we can only make this optimization where a hole would surely
1630 * be zero-filled if handle_mm_fault() actually did handle it.
1632 if ((flags
& FOLL_DUMP
) &&
1633 (!vma
->vm_ops
|| !vma
->vm_ops
->fault
))
1634 return ERR_PTR(-EFAULT
);
1638 static inline int stack_guard_page(struct vm_area_struct
*vma
, unsigned long addr
)
1640 return stack_guard_page_start(vma
, addr
) ||
1641 stack_guard_page_end(vma
, addr
+PAGE_SIZE
);
1645 * __get_user_pages() - pin user pages in memory
1646 * @tsk: task_struct of target task
1647 * @mm: mm_struct of target mm
1648 * @start: starting user address
1649 * @nr_pages: number of pages from start to pin
1650 * @gup_flags: flags modifying pin behaviour
1651 * @pages: array that receives pointers to the pages pinned.
1652 * Should be at least nr_pages long. Or NULL, if caller
1653 * only intends to ensure the pages are faulted in.
1654 * @vmas: array of pointers to vmas corresponding to each page.
1655 * Or NULL if the caller does not require them.
1656 * @nonblocking: whether waiting for disk IO or mmap_sem contention
1658 * Returns number of pages pinned. This may be fewer than the number
1659 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1660 * were pinned, returns -errno. Each page returned must be released
1661 * with a put_page() call when it is finished with. vmas will only
1662 * remain valid while mmap_sem is held.
1664 * Must be called with mmap_sem held for read or write.
1666 * __get_user_pages walks a process's page tables and takes a reference to
1667 * each struct page that each user address corresponds to at a given
1668 * instant. That is, it takes the page that would be accessed if a user
1669 * thread accesses the given user virtual address at that instant.
1671 * This does not guarantee that the page exists in the user mappings when
1672 * __get_user_pages returns, and there may even be a completely different
1673 * page there in some cases (eg. if mmapped pagecache has been invalidated
1674 * and subsequently re faulted). However it does guarantee that the page
1675 * won't be freed completely. And mostly callers simply care that the page
1676 * contains data that was valid *at some point in time*. Typically, an IO
1677 * or similar operation cannot guarantee anything stronger anyway because
1678 * locks can't be held over the syscall boundary.
1680 * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
1681 * the page is written to, set_page_dirty (or set_page_dirty_lock, as
1682 * appropriate) must be called after the page is finished with, and
1683 * before put_page is called.
1685 * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
1686 * or mmap_sem contention, and if waiting is needed to pin all pages,
1687 * *@nonblocking will be set to 0.
1689 * In most cases, get_user_pages or get_user_pages_fast should be used
1690 * instead of __get_user_pages. __get_user_pages should be used only if
1691 * you need some special @gup_flags.
1693 long __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1694 unsigned long start
, unsigned long nr_pages
,
1695 unsigned int gup_flags
, struct page
**pages
,
1696 struct vm_area_struct
**vmas
, int *nonblocking
)
1699 unsigned long vm_flags
;
1700 unsigned int page_mask
;
1705 VM_BUG_ON(!!pages
!= !!(gup_flags
& FOLL_GET
));
1708 * Require read or write permissions.
1709 * If FOLL_FORCE is set, we only require the "MAY" flags.
1711 vm_flags
= (gup_flags
& FOLL_WRITE
) ?
1712 (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
1713 vm_flags
&= (gup_flags
& FOLL_FORCE
) ?
1714 (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
1717 * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
1718 * would be called on PROT_NONE ranges. We must never invoke
1719 * handle_mm_fault on PROT_NONE ranges or the NUMA hinting
1720 * page faults would unprotect the PROT_NONE ranges if
1721 * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd
1722 * bitflag. So to avoid that, don't set FOLL_NUMA if
1723 * FOLL_FORCE is set.
1725 if (!(gup_flags
& FOLL_FORCE
))
1726 gup_flags
|= FOLL_NUMA
;
1731 struct vm_area_struct
*vma
;
1733 vma
= find_extend_vma(mm
, start
);
1734 if (!vma
&& in_gate_area(mm
, start
)) {
1735 unsigned long pg
= start
& PAGE_MASK
;
1741 /* user gate pages are read-only */
1742 if (gup_flags
& FOLL_WRITE
)
1743 return i
? : -EFAULT
;
1745 pgd
= pgd_offset_k(pg
);
1747 pgd
= pgd_offset_gate(mm
, pg
);
1748 BUG_ON(pgd_none(*pgd
));
1749 pud
= pud_offset(pgd
, pg
);
1750 BUG_ON(pud_none(*pud
));
1751 pmd
= pmd_offset(pud
, pg
);
1753 return i
? : -EFAULT
;
1754 VM_BUG_ON(pmd_trans_huge(*pmd
));
1755 pte
= pte_offset_map(pmd
, pg
);
1756 if (pte_none(*pte
)) {
1758 return i
? : -EFAULT
;
1760 vma
= get_gate_vma(mm
);
1764 page
= vm_normal_page(vma
, start
, *pte
);
1766 if (!(gup_flags
& FOLL_DUMP
) &&
1767 is_zero_pfn(pte_pfn(*pte
)))
1768 page
= pte_page(*pte
);
1771 return i
? : -EFAULT
;
1783 (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
1784 !(vm_flags
& vma
->vm_flags
))
1785 return i
? : -EFAULT
;
1787 if (is_vm_hugetlb_page(vma
)) {
1788 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1789 &start
, &nr_pages
, i
, gup_flags
);
1795 unsigned int foll_flags
= gup_flags
;
1796 unsigned int page_increm
;
1799 * If we have a pending SIGKILL, don't keep faulting
1800 * pages and potentially allocating memory.
1802 if (unlikely(fatal_signal_pending(current
)))
1803 return i
? i
: -ERESTARTSYS
;
1806 while (!(page
= follow_page_mask(vma
, start
,
1807 foll_flags
, &page_mask
))) {
1809 unsigned int fault_flags
= 0;
1811 /* For mlock, just skip the stack guard page. */
1812 if (foll_flags
& FOLL_MLOCK
) {
1813 if (stack_guard_page(vma
, start
))
1816 if (foll_flags
& FOLL_WRITE
)
1817 fault_flags
|= FAULT_FLAG_WRITE
;
1819 fault_flags
|= FAULT_FLAG_ALLOW_RETRY
;
1820 if (foll_flags
& FOLL_NOWAIT
)
1821 fault_flags
|= (FAULT_FLAG_ALLOW_RETRY
| FAULT_FLAG_RETRY_NOWAIT
);
1823 ret
= handle_mm_fault(mm
, vma
, start
,
1826 if (ret
& VM_FAULT_ERROR
) {
1827 if (ret
& VM_FAULT_OOM
)
1828 return i
? i
: -ENOMEM
;
1829 if (ret
& (VM_FAULT_HWPOISON
|
1830 VM_FAULT_HWPOISON_LARGE
)) {
1833 else if (gup_flags
& FOLL_HWPOISON
)
1838 if (ret
& VM_FAULT_SIGBUS
)
1839 return i
? i
: -EFAULT
;
1844 if (ret
& VM_FAULT_MAJOR
)
1850 if (ret
& VM_FAULT_RETRY
) {
1857 * The VM_FAULT_WRITE bit tells us that
1858 * do_wp_page has broken COW when necessary,
1859 * even if maybe_mkwrite decided not to set
1860 * pte_write. We can thus safely do subsequent
1861 * page lookups as if they were reads. But only
1862 * do so when looping for pte_write is futile:
1863 * in some cases userspace may also be wanting
1864 * to write to the gotten user page, which a
1865 * read fault here might prevent (a readonly
1866 * page might get reCOWed by userspace write).
1868 if ((ret
& VM_FAULT_WRITE
) &&
1869 !(vma
->vm_flags
& VM_WRITE
))
1870 foll_flags
&= ~FOLL_WRITE
;
1875 return i
? i
: PTR_ERR(page
);
1879 flush_anon_page(vma
, page
, start
);
1880 flush_dcache_page(page
);
1888 page_increm
= 1 + (~(start
>> PAGE_SHIFT
) & page_mask
);
1889 if (page_increm
> nr_pages
)
1890 page_increm
= nr_pages
;
1892 start
+= page_increm
* PAGE_SIZE
;
1893 nr_pages
-= page_increm
;
1894 } while (nr_pages
&& start
< vma
->vm_end
);
1898 EXPORT_SYMBOL(__get_user_pages
);
1901 * fixup_user_fault() - manually resolve a user page fault
1902 * @tsk: the task_struct to use for page fault accounting, or
1903 * NULL if faults are not to be recorded.
1904 * @mm: mm_struct of target mm
1905 * @address: user address
1906 * @fault_flags:flags to pass down to handle_mm_fault()
1908 * This is meant to be called in the specific scenario where for locking reasons
1909 * we try to access user memory in atomic context (within a pagefault_disable()
1910 * section), this returns -EFAULT, and we want to resolve the user fault before
1913 * Typically this is meant to be used by the futex code.
1915 * The main difference with get_user_pages() is that this function will
1916 * unconditionally call handle_mm_fault() which will in turn perform all the
1917 * necessary SW fixup of the dirty and young bits in the PTE, while
1918 * handle_mm_fault() only guarantees to update these in the struct page.
1920 * This is important for some architectures where those bits also gate the
1921 * access permission to the page because they are maintained in software. On
1922 * such architectures, gup() will not be enough to make a subsequent access
1925 * This should be called with the mm_sem held for read.
1927 int fixup_user_fault(struct task_struct
*tsk
, struct mm_struct
*mm
,
1928 unsigned long address
, unsigned int fault_flags
)
1930 struct vm_area_struct
*vma
;
1933 vma
= find_extend_vma(mm
, address
);
1934 if (!vma
|| address
< vma
->vm_start
)
1937 ret
= handle_mm_fault(mm
, vma
, address
, fault_flags
);
1938 if (ret
& VM_FAULT_ERROR
) {
1939 if (ret
& VM_FAULT_OOM
)
1941 if (ret
& (VM_FAULT_HWPOISON
| VM_FAULT_HWPOISON_LARGE
))
1943 if (ret
& VM_FAULT_SIGBUS
)
1948 if (ret
& VM_FAULT_MAJOR
)
1957 * get_user_pages() - pin user pages in memory
1958 * @tsk: the task_struct to use for page fault accounting, or
1959 * NULL if faults are not to be recorded.
1960 * @mm: mm_struct of target mm
1961 * @start: starting user address
1962 * @nr_pages: number of pages from start to pin
1963 * @write: whether pages will be written to by the caller
1964 * @force: whether to force write access even if user mapping is
1965 * readonly. This will result in the page being COWed even
1966 * in MAP_SHARED mappings. You do not want this.
1967 * @pages: array that receives pointers to the pages pinned.
1968 * Should be at least nr_pages long. Or NULL, if caller
1969 * only intends to ensure the pages are faulted in.
1970 * @vmas: array of pointers to vmas corresponding to each page.
1971 * Or NULL if the caller does not require them.
1973 * Returns number of pages pinned. This may be fewer than the number
1974 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1975 * were pinned, returns -errno. Each page returned must be released
1976 * with a put_page() call when it is finished with. vmas will only
1977 * remain valid while mmap_sem is held.
1979 * Must be called with mmap_sem held for read or write.
1981 * get_user_pages walks a process's page tables and takes a reference to
1982 * each struct page that each user address corresponds to at a given
1983 * instant. That is, it takes the page that would be accessed if a user
1984 * thread accesses the given user virtual address at that instant.
1986 * This does not guarantee that the page exists in the user mappings when
1987 * get_user_pages returns, and there may even be a completely different
1988 * page there in some cases (eg. if mmapped pagecache has been invalidated
1989 * and subsequently re faulted). However it does guarantee that the page
1990 * won't be freed completely. And mostly callers simply care that the page
1991 * contains data that was valid *at some point in time*. Typically, an IO
1992 * or similar operation cannot guarantee anything stronger anyway because
1993 * locks can't be held over the syscall boundary.
1995 * If write=0, the page must not be written to. If the page is written to,
1996 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1997 * after the page is finished with, and before put_page is called.
1999 * get_user_pages is typically used for fewer-copy IO operations, to get a
2000 * handle on the memory by some means other than accesses via the user virtual
2001 * addresses. The pages may be submitted for DMA to devices or accessed via
2002 * their kernel linear mapping (via the kmap APIs). Care should be taken to
2003 * use the correct cache flushing APIs.
2005 * See also get_user_pages_fast, for performance critical applications.
2007 long get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
2008 unsigned long start
, unsigned long nr_pages
, int write
,
2009 int force
, struct page
**pages
, struct vm_area_struct
**vmas
)
2011 int flags
= FOLL_TOUCH
;
2016 flags
|= FOLL_WRITE
;
2018 flags
|= FOLL_FORCE
;
2020 return __get_user_pages(tsk
, mm
, start
, nr_pages
, flags
, pages
, vmas
,
2023 EXPORT_SYMBOL(get_user_pages
);
2026 * get_dump_page() - pin user page in memory while writing it to core dump
2027 * @addr: user address
2029 * Returns struct page pointer of user page pinned for dump,
2030 * to be freed afterwards by page_cache_release() or put_page().
2032 * Returns NULL on any kind of failure - a hole must then be inserted into
2033 * the corefile, to preserve alignment with its headers; and also returns
2034 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
2035 * allowing a hole to be left in the corefile to save diskspace.
2037 * Called without mmap_sem, but after all other threads have been killed.
2039 #ifdef CONFIG_ELF_CORE
2040 struct page
*get_dump_page(unsigned long addr
)
2042 struct vm_area_struct
*vma
;
2045 if (__get_user_pages(current
, current
->mm
, addr
, 1,
2046 FOLL_FORCE
| FOLL_DUMP
| FOLL_GET
, &page
, &vma
,
2049 flush_cache_page(vma
, addr
, page_to_pfn(page
));
2052 #endif /* CONFIG_ELF_CORE */
2054 pte_t
*__get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
2057 pgd_t
* pgd
= pgd_offset(mm
, addr
);
2058 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
2060 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
2062 VM_BUG_ON(pmd_trans_huge(*pmd
));
2063 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
2070 * This is the old fallback for page remapping.
2072 * For historical reasons, it only allows reserved pages. Only
2073 * old drivers should use this, and they needed to mark their
2074 * pages reserved for the old functions anyway.
2076 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
2077 struct page
*page
, pgprot_t prot
)
2079 struct mm_struct
*mm
= vma
->vm_mm
;
2088 flush_dcache_page(page
);
2089 pte
= get_locked_pte(mm
, addr
, &ptl
);
2093 if (!pte_none(*pte
))
2096 /* Ok, finally just insert the thing.. */
2098 inc_mm_counter_fast(mm
, MM_FILEPAGES
);
2099 page_add_file_rmap(page
);
2100 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
2103 pte_unmap_unlock(pte
, ptl
);
2106 pte_unmap_unlock(pte
, ptl
);
2112 * vm_insert_page - insert single page into user vma
2113 * @vma: user vma to map to
2114 * @addr: target user address of this page
2115 * @page: source kernel page
2117 * This allows drivers to insert individual pages they've allocated
2120 * The page has to be a nice clean _individual_ kernel allocation.
2121 * If you allocate a compound page, you need to have marked it as
2122 * such (__GFP_COMP), or manually just split the page up yourself
2123 * (see split_page()).
2125 * NOTE! Traditionally this was done with "remap_pfn_range()" which
2126 * took an arbitrary page protection parameter. This doesn't allow
2127 * that. Your vma protection will have to be set up correctly, which
2128 * means that if you want a shared writable mapping, you'd better
2129 * ask for a shared writable mapping!
2131 * The page does not need to be reserved.
2133 * Usually this function is called from f_op->mmap() handler
2134 * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
2135 * Caller must set VM_MIXEDMAP on vma if it wants to call this
2136 * function from other places, for example from page-fault handler.
2138 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
2141 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
2143 if (!page_count(page
))
2145 if (!(vma
->vm_flags
& VM_MIXEDMAP
)) {
2146 BUG_ON(down_read_trylock(&vma
->vm_mm
->mmap_sem
));
2147 BUG_ON(vma
->vm_flags
& VM_PFNMAP
);
2148 vma
->vm_flags
|= VM_MIXEDMAP
;
2150 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
2152 EXPORT_SYMBOL(vm_insert_page
);
2154 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
2155 unsigned long pfn
, pgprot_t prot
)
2157 struct mm_struct
*mm
= vma
->vm_mm
;
2163 pte
= get_locked_pte(mm
, addr
, &ptl
);
2167 if (!pte_none(*pte
))
2170 /* Ok, finally just insert the thing.. */
2171 entry
= pte_mkspecial(pfn_pte(pfn
, prot
));
2172 set_pte_at(mm
, addr
, pte
, entry
);
2173 update_mmu_cache(vma
, addr
, pte
); /* XXX: why not for insert_page? */
2177 pte_unmap_unlock(pte
, ptl
);
2183 * vm_insert_pfn - insert single pfn into user vma
2184 * @vma: user vma to map to
2185 * @addr: target user address of this page
2186 * @pfn: source kernel pfn
2188 * Similar to vm_insert_page, this allows drivers to insert individual pages
2189 * they've allocated into a user vma. Same comments apply.
2191 * This function should only be called from a vm_ops->fault handler, and
2192 * in that case the handler should return NULL.
2194 * vma cannot be a COW mapping.
2196 * As this is called only for pages that do not currently exist, we
2197 * do not need to flush old virtual caches or the TLB.
2199 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
2203 pgprot_t pgprot
= vma
->vm_page_prot
;
2205 * Technically, architectures with pte_special can avoid all these
2206 * restrictions (same for remap_pfn_range). However we would like
2207 * consistency in testing and feature parity among all, so we should
2208 * try to keep these invariants in place for everybody.
2210 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
2211 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
2212 (VM_PFNMAP
|VM_MIXEDMAP
));
2213 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
2214 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
2216 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
2218 if (track_pfn_insert(vma
, &pgprot
, pfn
))
2221 ret
= insert_pfn(vma
, addr
, pfn
, pgprot
);
2225 EXPORT_SYMBOL(vm_insert_pfn
);
2227 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
2230 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
2232 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
2236 * If we don't have pte special, then we have to use the pfn_valid()
2237 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
2238 * refcount the page if pfn_valid is true (hence insert_page rather
2239 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
2240 * without pte special, it would there be refcounted as a normal page.
2242 if (!HAVE_PTE_SPECIAL
&& pfn_valid(pfn
)) {
2245 page
= pfn_to_page(pfn
);
2246 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
2248 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
2250 EXPORT_SYMBOL(vm_insert_mixed
);
2253 * maps a range of physical memory into the requested pages. the old
2254 * mappings are removed. any references to nonexistent pages results
2255 * in null mappings (currently treated as "copy-on-access")
2257 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
2258 unsigned long addr
, unsigned long end
,
2259 unsigned long pfn
, pgprot_t prot
)
2264 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
2267 arch_enter_lazy_mmu_mode();
2269 BUG_ON(!pte_none(*pte
));
2270 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
2272 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
2273 arch_leave_lazy_mmu_mode();
2274 pte_unmap_unlock(pte
- 1, ptl
);
2278 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
2279 unsigned long addr
, unsigned long end
,
2280 unsigned long pfn
, pgprot_t prot
)
2285 pfn
-= addr
>> PAGE_SHIFT
;
2286 pmd
= pmd_alloc(mm
, pud
, addr
);
2289 VM_BUG_ON(pmd_trans_huge(*pmd
));
2291 next
= pmd_addr_end(addr
, end
);
2292 if (remap_pte_range(mm
, pmd
, addr
, next
,
2293 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
2295 } while (pmd
++, addr
= next
, addr
!= end
);
2299 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
2300 unsigned long addr
, unsigned long end
,
2301 unsigned long pfn
, pgprot_t prot
)
2306 pfn
-= addr
>> PAGE_SHIFT
;
2307 pud
= pud_alloc(mm
, pgd
, addr
);
2311 next
= pud_addr_end(addr
, end
);
2312 if (remap_pmd_range(mm
, pud
, addr
, next
,
2313 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
2315 } while (pud
++, addr
= next
, addr
!= end
);
2320 * remap_pfn_range - remap kernel memory to userspace
2321 * @vma: user vma to map to
2322 * @addr: target user address to start at
2323 * @pfn: physical address of kernel memory
2324 * @size: size of map area
2325 * @prot: page protection flags for this mapping
2327 * Note: this is only safe if the mm semaphore is held when called.
2329 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
2330 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
2334 unsigned long end
= addr
+ PAGE_ALIGN(size
);
2335 struct mm_struct
*mm
= vma
->vm_mm
;
2339 * Physically remapped pages are special. Tell the
2340 * rest of the world about it:
2341 * VM_IO tells people not to look at these pages
2342 * (accesses can have side effects).
2343 * VM_PFNMAP tells the core MM that the base pages are just
2344 * raw PFN mappings, and do not have a "struct page" associated
2347 * Disable vma merging and expanding with mremap().
2349 * Omit vma from core dump, even when VM_IO turned off.
2351 * There's a horrible special case to handle copy-on-write
2352 * behaviour that some programs depend on. We mark the "original"
2353 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
2354 * See vm_normal_page() for details.
2356 if (is_cow_mapping(vma
->vm_flags
)) {
2357 if (addr
!= vma
->vm_start
|| end
!= vma
->vm_end
)
2359 vma
->vm_pgoff
= pfn
;
2362 err
= track_pfn_remap(vma
, &prot
, pfn
, addr
, PAGE_ALIGN(size
));
2366 vma
->vm_flags
|= VM_IO
| VM_PFNMAP
| VM_DONTEXPAND
| VM_DONTDUMP
;
2368 BUG_ON(addr
>= end
);
2369 pfn
-= addr
>> PAGE_SHIFT
;
2370 pgd
= pgd_offset(mm
, addr
);
2371 flush_cache_range(vma
, addr
, end
);
2373 next
= pgd_addr_end(addr
, end
);
2374 err
= remap_pud_range(mm
, pgd
, addr
, next
,
2375 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
2378 } while (pgd
++, addr
= next
, addr
!= end
);
2381 untrack_pfn(vma
, pfn
, PAGE_ALIGN(size
));
2385 EXPORT_SYMBOL(remap_pfn_range
);
2388 * vm_iomap_memory - remap memory to userspace
2389 * @vma: user vma to map to
2390 * @start: start of area
2391 * @len: size of area
2393 * This is a simplified io_remap_pfn_range() for common driver use. The
2394 * driver just needs to give us the physical memory range to be mapped,
2395 * we'll figure out the rest from the vma information.
2397 * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
2398 * whatever write-combining details or similar.
2400 int vm_iomap_memory(struct vm_area_struct
*vma
, phys_addr_t start
, unsigned long len
)
2402 unsigned long vm_len
, pfn
, pages
;
2404 /* Check that the physical memory area passed in looks valid */
2405 if (start
+ len
< start
)
2408 * You *really* shouldn't map things that aren't page-aligned,
2409 * but we've historically allowed it because IO memory might
2410 * just have smaller alignment.
2412 len
+= start
& ~PAGE_MASK
;
2413 pfn
= start
>> PAGE_SHIFT
;
2414 pages
= (len
+ ~PAGE_MASK
) >> PAGE_SHIFT
;
2415 if (pfn
+ pages
< pfn
)
2418 /* We start the mapping 'vm_pgoff' pages into the area */
2419 if (vma
->vm_pgoff
> pages
)
2421 pfn
+= vma
->vm_pgoff
;
2422 pages
-= vma
->vm_pgoff
;
2424 /* Can we fit all of the mapping? */
2425 vm_len
= vma
->vm_end
- vma
->vm_start
;
2426 if (vm_len
>> PAGE_SHIFT
> pages
)
2429 /* Ok, let it rip */
2430 return io_remap_pfn_range(vma
, vma
->vm_start
, pfn
, vm_len
, vma
->vm_page_prot
);
2432 EXPORT_SYMBOL(vm_iomap_memory
);
2434 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
2435 unsigned long addr
, unsigned long end
,
2436 pte_fn_t fn
, void *data
)
2441 spinlock_t
*uninitialized_var(ptl
);
2443 pte
= (mm
== &init_mm
) ?
2444 pte_alloc_kernel(pmd
, addr
) :
2445 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
2449 BUG_ON(pmd_huge(*pmd
));
2451 arch_enter_lazy_mmu_mode();
2453 token
= pmd_pgtable(*pmd
);
2456 err
= fn(pte
++, token
, addr
, data
);
2459 } while (addr
+= PAGE_SIZE
, addr
!= end
);
2461 arch_leave_lazy_mmu_mode();
2464 pte_unmap_unlock(pte
-1, ptl
);
2468 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
2469 unsigned long addr
, unsigned long end
,
2470 pte_fn_t fn
, void *data
)
2476 BUG_ON(pud_huge(*pud
));
2478 pmd
= pmd_alloc(mm
, pud
, addr
);
2482 next
= pmd_addr_end(addr
, end
);
2483 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
2486 } while (pmd
++, addr
= next
, addr
!= end
);
2490 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
2491 unsigned long addr
, unsigned long end
,
2492 pte_fn_t fn
, void *data
)
2498 pud
= pud_alloc(mm
, pgd
, addr
);
2502 next
= pud_addr_end(addr
, end
);
2503 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
2506 } while (pud
++, addr
= next
, addr
!= end
);
2511 * Scan a region of virtual memory, filling in page tables as necessary
2512 * and calling a provided function on each leaf page table.
2514 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
2515 unsigned long size
, pte_fn_t fn
, void *data
)
2519 unsigned long end
= addr
+ size
;
2522 BUG_ON(addr
>= end
);
2523 pgd
= pgd_offset(mm
, addr
);
2525 next
= pgd_addr_end(addr
, end
);
2526 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
2529 } while (pgd
++, addr
= next
, addr
!= end
);
2533 EXPORT_SYMBOL_GPL(apply_to_page_range
);
2536 * handle_pte_fault chooses page fault handler according to an entry
2537 * which was read non-atomically. Before making any commitment, on
2538 * those architectures or configurations (e.g. i386 with PAE) which
2539 * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
2540 * must check under lock before unmapping the pte and proceeding
2541 * (but do_wp_page is only called after already making such a check;
2542 * and do_anonymous_page can safely check later on).
2544 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
2545 pte_t
*page_table
, pte_t orig_pte
)
2548 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2549 if (sizeof(pte_t
) > sizeof(unsigned long)) {
2550 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
2552 same
= pte_same(*page_table
, orig_pte
);
2556 pte_unmap(page_table
);
2560 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
2563 * If the source page was a PFN mapping, we don't have
2564 * a "struct page" for it. We do a best-effort copy by
2565 * just copying from the original user address. If that
2566 * fails, we just zero-fill it. Live with it.
2568 if (unlikely(!src
)) {
2569 void *kaddr
= kmap_atomic(dst
);
2570 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
2573 * This really shouldn't fail, because the page is there
2574 * in the page tables. But it might just be unreadable,
2575 * in which case we just give up and fill the result with
2578 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
2580 kunmap_atomic(kaddr
);
2581 flush_dcache_page(dst
);
2583 copy_user_highpage(dst
, src
, va
, vma
);
2587 * This routine handles present pages, when users try to write
2588 * to a shared page. It is done by copying the page to a new address
2589 * and decrementing the shared-page counter for the old page.
2591 * Note that this routine assumes that the protection checks have been
2592 * done by the caller (the low-level page fault routine in most cases).
2593 * Thus we can safely just mark it writable once we've done any necessary
2596 * We also mark the page dirty at this point even though the page will
2597 * change only once the write actually happens. This avoids a few races,
2598 * and potentially makes it more efficient.
2600 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2601 * but allow concurrent faults), with pte both mapped and locked.
2602 * We return with mmap_sem still held, but pte unmapped and unlocked.
2604 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2605 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2606 spinlock_t
*ptl
, pte_t orig_pte
)
2609 struct page
*old_page
, *new_page
= NULL
;
2612 int page_mkwrite
= 0;
2613 struct page
*dirty_page
= NULL
;
2614 unsigned long mmun_start
= 0; /* For mmu_notifiers */
2615 unsigned long mmun_end
= 0; /* For mmu_notifiers */
2617 old_page
= vm_normal_page(vma
, address
, orig_pte
);
2620 * VM_MIXEDMAP !pfn_valid() case
2622 * We should not cow pages in a shared writeable mapping.
2623 * Just mark the pages writable as we can't do any dirty
2624 * accounting on raw pfn maps.
2626 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
2627 (VM_WRITE
|VM_SHARED
))
2633 * Take out anonymous pages first, anonymous shared vmas are
2634 * not dirty accountable.
2636 if (PageAnon(old_page
) && !PageKsm(old_page
)) {
2637 if (!trylock_page(old_page
)) {
2638 page_cache_get(old_page
);
2639 pte_unmap_unlock(page_table
, ptl
);
2640 lock_page(old_page
);
2641 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
2643 if (!pte_same(*page_table
, orig_pte
)) {
2644 unlock_page(old_page
);
2647 page_cache_release(old_page
);
2649 if (reuse_swap_page(old_page
)) {
2651 * The page is all ours. Move it to our anon_vma so
2652 * the rmap code will not search our parent or siblings.
2653 * Protected against the rmap code by the page lock.
2655 page_move_anon_rmap(old_page
, vma
, address
);
2656 unlock_page(old_page
);
2659 unlock_page(old_page
);
2660 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
2661 (VM_WRITE
|VM_SHARED
))) {
2663 * Only catch write-faults on shared writable pages,
2664 * read-only shared pages can get COWed by
2665 * get_user_pages(.write=1, .force=1).
2667 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
2668 struct vm_fault vmf
;
2671 vmf
.virtual_address
= (void __user
*)(address
&
2673 vmf
.pgoff
= old_page
->index
;
2674 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2675 vmf
.page
= old_page
;
2678 * Notify the address space that the page is about to
2679 * become writable so that it can prohibit this or wait
2680 * for the page to get into an appropriate state.
2682 * We do this without the lock held, so that it can
2683 * sleep if it needs to.
2685 page_cache_get(old_page
);
2686 pte_unmap_unlock(page_table
, ptl
);
2688 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2690 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2692 goto unwritable_page
;
2694 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2695 lock_page(old_page
);
2696 if (!old_page
->mapping
) {
2697 ret
= 0; /* retry the fault */
2698 unlock_page(old_page
);
2699 goto unwritable_page
;
2702 VM_BUG_ON(!PageLocked(old_page
));
2705 * Since we dropped the lock we need to revalidate
2706 * the PTE as someone else may have changed it. If
2707 * they did, we just return, as we can count on the
2708 * MMU to tell us if they didn't also make it writable.
2710 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
2712 if (!pte_same(*page_table
, orig_pte
)) {
2713 unlock_page(old_page
);
2719 dirty_page
= old_page
;
2720 get_page(dirty_page
);
2724 * Clear the pages cpupid information as the existing
2725 * information potentially belongs to a now completely
2726 * unrelated process.
2729 page_cpupid_xchg_last(old_page
, (1 << LAST_CPUPID_SHIFT
) - 1);
2731 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2732 entry
= pte_mkyoung(orig_pte
);
2733 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2734 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1))
2735 update_mmu_cache(vma
, address
, page_table
);
2736 pte_unmap_unlock(page_table
, ptl
);
2737 ret
|= VM_FAULT_WRITE
;
2743 * Yes, Virginia, this is actually required to prevent a race
2744 * with clear_page_dirty_for_io() from clearing the page dirty
2745 * bit after it clear all dirty ptes, but before a racing
2746 * do_wp_page installs a dirty pte.
2748 * __do_fault is protected similarly.
2750 if (!page_mkwrite
) {
2751 wait_on_page_locked(dirty_page
);
2752 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2753 /* file_update_time outside page_lock */
2755 file_update_time(vma
->vm_file
);
2757 put_page(dirty_page
);
2759 struct address_space
*mapping
= dirty_page
->mapping
;
2761 set_page_dirty(dirty_page
);
2762 unlock_page(dirty_page
);
2763 page_cache_release(dirty_page
);
2766 * Some device drivers do not set page.mapping
2767 * but still dirty their pages
2769 balance_dirty_pages_ratelimited(mapping
);
2777 * Ok, we need to copy. Oh, well..
2779 page_cache_get(old_page
);
2781 pte_unmap_unlock(page_table
, ptl
);
2783 if (unlikely(anon_vma_prepare(vma
)))
2786 if (is_zero_pfn(pte_pfn(orig_pte
))) {
2787 new_page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2791 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
2794 cow_user_page(new_page
, old_page
, address
, vma
);
2796 __SetPageUptodate(new_page
);
2798 if (mem_cgroup_newpage_charge(new_page
, mm
, GFP_KERNEL
))
2801 mmun_start
= address
& PAGE_MASK
;
2802 mmun_end
= mmun_start
+ PAGE_SIZE
;
2803 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2806 * Re-check the pte - we dropped the lock
2808 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2809 if (likely(pte_same(*page_table
, orig_pte
))) {
2811 if (!PageAnon(old_page
)) {
2812 dec_mm_counter_fast(mm
, MM_FILEPAGES
);
2813 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
2816 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
2817 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2818 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2819 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2821 * Clear the pte entry and flush it first, before updating the
2822 * pte with the new entry. This will avoid a race condition
2823 * seen in the presence of one thread doing SMC and another
2826 ptep_clear_flush(vma
, address
, page_table
);
2827 page_add_new_anon_rmap(new_page
, vma
, address
);
2829 * We call the notify macro here because, when using secondary
2830 * mmu page tables (such as kvm shadow page tables), we want the
2831 * new page to be mapped directly into the secondary page table.
2833 set_pte_at_notify(mm
, address
, page_table
, entry
);
2834 update_mmu_cache(vma
, address
, page_table
);
2837 * Only after switching the pte to the new page may
2838 * we remove the mapcount here. Otherwise another
2839 * process may come and find the rmap count decremented
2840 * before the pte is switched to the new page, and
2841 * "reuse" the old page writing into it while our pte
2842 * here still points into it and can be read by other
2845 * The critical issue is to order this
2846 * page_remove_rmap with the ptp_clear_flush above.
2847 * Those stores are ordered by (if nothing else,)
2848 * the barrier present in the atomic_add_negative
2849 * in page_remove_rmap.
2851 * Then the TLB flush in ptep_clear_flush ensures that
2852 * no process can access the old page before the
2853 * decremented mapcount is visible. And the old page
2854 * cannot be reused until after the decremented
2855 * mapcount is visible. So transitively, TLBs to
2856 * old page will be flushed before it can be reused.
2858 page_remove_rmap(old_page
);
2861 /* Free the old page.. */
2862 new_page
= old_page
;
2863 ret
|= VM_FAULT_WRITE
;
2865 mem_cgroup_uncharge_page(new_page
);
2868 page_cache_release(new_page
);
2870 pte_unmap_unlock(page_table
, ptl
);
2871 if (mmun_end
> mmun_start
)
2872 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2875 * Don't let another task, with possibly unlocked vma,
2876 * keep the mlocked page.
2878 if ((ret
& VM_FAULT_WRITE
) && (vma
->vm_flags
& VM_LOCKED
)) {
2879 lock_page(old_page
); /* LRU manipulation */
2880 munlock_vma_page(old_page
);
2881 unlock_page(old_page
);
2883 page_cache_release(old_page
);
2887 page_cache_release(new_page
);
2890 page_cache_release(old_page
);
2891 return VM_FAULT_OOM
;
2894 page_cache_release(old_page
);
2898 static void unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2899 unsigned long start_addr
, unsigned long end_addr
,
2900 struct zap_details
*details
)
2902 zap_page_range_single(vma
, start_addr
, end_addr
- start_addr
, details
);
2905 static inline void unmap_mapping_range_tree(struct rb_root
*root
,
2906 struct zap_details
*details
)
2908 struct vm_area_struct
*vma
;
2909 pgoff_t vba
, vea
, zba
, zea
;
2911 vma_interval_tree_foreach(vma
, root
,
2912 details
->first_index
, details
->last_index
) {
2914 vba
= vma
->vm_pgoff
;
2915 vea
= vba
+ vma_pages(vma
) - 1;
2916 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2917 zba
= details
->first_index
;
2920 zea
= details
->last_index
;
2924 unmap_mapping_range_vma(vma
,
2925 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2926 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2931 static inline void unmap_mapping_range_list(struct list_head
*head
,
2932 struct zap_details
*details
)
2934 struct vm_area_struct
*vma
;
2937 * In nonlinear VMAs there is no correspondence between virtual address
2938 * offset and file offset. So we must perform an exhaustive search
2939 * across *all* the pages in each nonlinear VMA, not just the pages
2940 * whose virtual address lies outside the file truncation point.
2942 list_for_each_entry(vma
, head
, shared
.nonlinear
) {
2943 details
->nonlinear_vma
= vma
;
2944 unmap_mapping_range_vma(vma
, vma
->vm_start
, vma
->vm_end
, details
);
2949 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2950 * @mapping: the address space containing mmaps to be unmapped.
2951 * @holebegin: byte in first page to unmap, relative to the start of
2952 * the underlying file. This will be rounded down to a PAGE_SIZE
2953 * boundary. Note that this is different from truncate_pagecache(), which
2954 * must keep the partial page. In contrast, we must get rid of
2956 * @holelen: size of prospective hole in bytes. This will be rounded
2957 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2959 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2960 * but 0 when invalidating pagecache, don't throw away private data.
2962 void unmap_mapping_range(struct address_space
*mapping
,
2963 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2965 struct zap_details details
;
2966 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2967 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2969 /* Check for overflow. */
2970 if (sizeof(holelen
) > sizeof(hlen
)) {
2972 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2973 if (holeend
& ~(long long)ULONG_MAX
)
2974 hlen
= ULONG_MAX
- hba
+ 1;
2977 details
.check_mapping
= even_cows
? NULL
: mapping
;
2978 details
.nonlinear_vma
= NULL
;
2979 details
.first_index
= hba
;
2980 details
.last_index
= hba
+ hlen
- 1;
2981 if (details
.last_index
< details
.first_index
)
2982 details
.last_index
= ULONG_MAX
;
2985 mutex_lock(&mapping
->i_mmap_mutex
);
2986 if (unlikely(!RB_EMPTY_ROOT(&mapping
->i_mmap
)))
2987 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2988 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
2989 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
2990 mutex_unlock(&mapping
->i_mmap_mutex
);
2992 EXPORT_SYMBOL(unmap_mapping_range
);
2995 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2996 * but allow concurrent faults), and pte mapped but not yet locked.
2997 * We return with mmap_sem still held, but pte unmapped and unlocked.
2999 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3000 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
3001 unsigned int flags
, pte_t orig_pte
)
3004 struct page
*page
, *swapcache
;
3008 struct mem_cgroup
*ptr
;
3012 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
3015 entry
= pte_to_swp_entry(orig_pte
);
3016 if (unlikely(non_swap_entry(entry
))) {
3017 if (is_migration_entry(entry
)) {
3018 migration_entry_wait(mm
, pmd
, address
);
3019 } else if (is_hwpoison_entry(entry
)) {
3020 ret
= VM_FAULT_HWPOISON
;
3022 print_bad_pte(vma
, address
, orig_pte
, NULL
);
3023 ret
= VM_FAULT_SIGBUS
;
3027 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
3028 page
= lookup_swap_cache(entry
);
3030 page
= swapin_readahead(entry
,
3031 GFP_HIGHUSER_MOVABLE
, vma
, address
);
3034 * Back out if somebody else faulted in this pte
3035 * while we released the pte lock.
3037 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
3038 if (likely(pte_same(*page_table
, orig_pte
)))
3040 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
3044 /* Had to read the page from swap area: Major fault */
3045 ret
= VM_FAULT_MAJOR
;
3046 count_vm_event(PGMAJFAULT
);
3047 mem_cgroup_count_vm_event(mm
, PGMAJFAULT
);
3048 } else if (PageHWPoison(page
)) {
3050 * hwpoisoned dirty swapcache pages are kept for killing
3051 * owner processes (which may be unknown at hwpoison time)
3053 ret
= VM_FAULT_HWPOISON
;
3054 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
3060 locked
= lock_page_or_retry(page
, mm
, flags
);
3062 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
3064 ret
|= VM_FAULT_RETRY
;
3069 * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
3070 * release the swapcache from under us. The page pin, and pte_same
3071 * test below, are not enough to exclude that. Even if it is still
3072 * swapcache, we need to check that the page's swap has not changed.
3074 if (unlikely(!PageSwapCache(page
) || page_private(page
) != entry
.val
))
3077 page
= ksm_might_need_to_copy(page
, vma
, address
);
3078 if (unlikely(!page
)) {
3084 if (mem_cgroup_try_charge_swapin(mm
, page
, GFP_KERNEL
, &ptr
)) {
3090 * Back out if somebody else already faulted in this pte.
3092 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
3093 if (unlikely(!pte_same(*page_table
, orig_pte
)))
3096 if (unlikely(!PageUptodate(page
))) {
3097 ret
= VM_FAULT_SIGBUS
;
3102 * The page isn't present yet, go ahead with the fault.
3104 * Be careful about the sequence of operations here.
3105 * To get its accounting right, reuse_swap_page() must be called
3106 * while the page is counted on swap but not yet in mapcount i.e.
3107 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
3108 * must be called after the swap_free(), or it will never succeed.
3109 * Because delete_from_swap_page() may be called by reuse_swap_page(),
3110 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
3111 * in page->private. In this case, a record in swap_cgroup is silently
3112 * discarded at swap_free().
3115 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
3116 dec_mm_counter_fast(mm
, MM_SWAPENTS
);
3117 pte
= mk_pte(page
, vma
->vm_page_prot
);
3118 if ((flags
& FAULT_FLAG_WRITE
) && reuse_swap_page(page
)) {
3119 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
3120 flags
&= ~FAULT_FLAG_WRITE
;
3121 ret
|= VM_FAULT_WRITE
;
3124 flush_icache_page(vma
, page
);
3125 if (pte_swp_soft_dirty(orig_pte
))
3126 pte
= pte_mksoft_dirty(pte
);
3127 set_pte_at(mm
, address
, page_table
, pte
);
3128 if (page
== swapcache
)
3129 do_page_add_anon_rmap(page
, vma
, address
, exclusive
);
3130 else /* ksm created a completely new copy */
3131 page_add_new_anon_rmap(page
, vma
, address
);
3132 /* It's better to call commit-charge after rmap is established */
3133 mem_cgroup_commit_charge_swapin(page
, ptr
);
3136 if (vm_swap_full() || (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
3137 try_to_free_swap(page
);
3139 if (page
!= swapcache
) {
3141 * Hold the lock to avoid the swap entry to be reused
3142 * until we take the PT lock for the pte_same() check
3143 * (to avoid false positives from pte_same). For
3144 * further safety release the lock after the swap_free
3145 * so that the swap count won't change under a
3146 * parallel locked swapcache.
3148 unlock_page(swapcache
);
3149 page_cache_release(swapcache
);
3152 if (flags
& FAULT_FLAG_WRITE
) {
3153 ret
|= do_wp_page(mm
, vma
, address
, page_table
, pmd
, ptl
, pte
);
3154 if (ret
& VM_FAULT_ERROR
)
3155 ret
&= VM_FAULT_ERROR
;
3159 /* No need to invalidate - it was non-present before */
3160 update_mmu_cache(vma
, address
, page_table
);
3162 pte_unmap_unlock(page_table
, ptl
);
3166 mem_cgroup_cancel_charge_swapin(ptr
);
3167 pte_unmap_unlock(page_table
, ptl
);
3171 page_cache_release(page
);
3172 if (page
!= swapcache
) {
3173 unlock_page(swapcache
);
3174 page_cache_release(swapcache
);
3180 * This is like a special single-page "expand_{down|up}wards()",
3181 * except we must first make sure that 'address{-|+}PAGE_SIZE'
3182 * doesn't hit another vma.
3184 static inline int check_stack_guard_page(struct vm_area_struct
*vma
, unsigned long address
)
3186 address
&= PAGE_MASK
;
3187 if ((vma
->vm_flags
& VM_GROWSDOWN
) && address
== vma
->vm_start
) {
3188 struct vm_area_struct
*prev
= vma
->vm_prev
;
3191 * Is there a mapping abutting this one below?
3193 * That's only ok if it's the same stack mapping
3194 * that has gotten split..
3196 if (prev
&& prev
->vm_end
== address
)
3197 return prev
->vm_flags
& VM_GROWSDOWN
? 0 : -ENOMEM
;
3199 expand_downwards(vma
, address
- PAGE_SIZE
);
3201 if ((vma
->vm_flags
& VM_GROWSUP
) && address
+ PAGE_SIZE
== vma
->vm_end
) {
3202 struct vm_area_struct
*next
= vma
->vm_next
;
3204 /* As VM_GROWSDOWN but s/below/above/ */
3205 if (next
&& next
->vm_start
== address
+ PAGE_SIZE
)
3206 return next
->vm_flags
& VM_GROWSUP
? 0 : -ENOMEM
;
3208 expand_upwards(vma
, address
+ PAGE_SIZE
);
3214 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3215 * but allow concurrent faults), and pte mapped but not yet locked.
3216 * We return with mmap_sem still held, but pte unmapped and unlocked.
3218 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3219 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
3226 pte_unmap(page_table
);
3228 /* Check if we need to add a guard page to the stack */
3229 if (check_stack_guard_page(vma
, address
) < 0)
3230 return VM_FAULT_SIGBUS
;
3232 /* Use the zero-page for reads */
3233 if (!(flags
& FAULT_FLAG_WRITE
)) {
3234 entry
= pte_mkspecial(pfn_pte(my_zero_pfn(address
),
3235 vma
->vm_page_prot
));
3236 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
3237 if (!pte_none(*page_table
))
3242 /* Allocate our own private page. */
3243 if (unlikely(anon_vma_prepare(vma
)))
3245 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
3249 * The memory barrier inside __SetPageUptodate makes sure that
3250 * preceeding stores to the page contents become visible before
3251 * the set_pte_at() write.
3253 __SetPageUptodate(page
);
3255 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
))
3258 entry
= mk_pte(page
, vma
->vm_page_prot
);
3259 if (vma
->vm_flags
& VM_WRITE
)
3260 entry
= pte_mkwrite(pte_mkdirty(entry
));
3262 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
3263 if (!pte_none(*page_table
))
3266 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
3267 page_add_new_anon_rmap(page
, vma
, address
);
3269 set_pte_at(mm
, address
, page_table
, entry
);
3271 /* No need to invalidate - it was non-present before */
3272 update_mmu_cache(vma
, address
, page_table
);
3274 pte_unmap_unlock(page_table
, ptl
);
3277 mem_cgroup_uncharge_page(page
);
3278 page_cache_release(page
);
3281 page_cache_release(page
);
3283 return VM_FAULT_OOM
;
3287 * __do_fault() tries to create a new page mapping. It aggressively
3288 * tries to share with existing pages, but makes a separate copy if
3289 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
3290 * the next page fault.
3292 * As this is called only for pages that do not currently exist, we
3293 * do not need to flush old virtual caches or the TLB.
3295 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3296 * but allow concurrent faults), and pte neither mapped nor locked.
3297 * We return with mmap_sem still held, but pte unmapped and unlocked.
3299 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3300 unsigned long address
, pmd_t
*pmd
,
3301 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
3306 struct page
*cow_page
;
3309 struct page
*dirty_page
= NULL
;
3310 struct vm_fault vmf
;
3312 int page_mkwrite
= 0;
3315 * If we do COW later, allocate page befor taking lock_page()
3316 * on the file cache page. This will reduce lock holding time.
3318 if ((flags
& FAULT_FLAG_WRITE
) && !(vma
->vm_flags
& VM_SHARED
)) {
3320 if (unlikely(anon_vma_prepare(vma
)))
3321 return VM_FAULT_OOM
;
3323 cow_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
3325 return VM_FAULT_OOM
;
3327 if (mem_cgroup_newpage_charge(cow_page
, mm
, GFP_KERNEL
)) {
3328 page_cache_release(cow_page
);
3329 return VM_FAULT_OOM
;
3334 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
3339 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
3340 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
|
3344 if (unlikely(PageHWPoison(vmf
.page
))) {
3345 if (ret
& VM_FAULT_LOCKED
)
3346 unlock_page(vmf
.page
);
3347 ret
= VM_FAULT_HWPOISON
;
3352 * For consistency in subsequent calls, make the faulted page always
3355 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
3356 lock_page(vmf
.page
);
3358 VM_BUG_ON(!PageLocked(vmf
.page
));
3361 * Should we do an early C-O-W break?
3364 if (flags
& FAULT_FLAG_WRITE
) {
3365 if (!(vma
->vm_flags
& VM_SHARED
)) {
3368 copy_user_highpage(page
, vmf
.page
, address
, vma
);
3369 __SetPageUptodate(page
);
3372 * If the page will be shareable, see if the backing
3373 * address space wants to know that the page is about
3374 * to become writable
3376 if (vma
->vm_ops
->page_mkwrite
) {
3380 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
3381 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
3383 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
3385 goto unwritable_page
;
3387 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
3389 if (!page
->mapping
) {
3390 ret
= 0; /* retry the fault */
3392 goto unwritable_page
;
3395 VM_BUG_ON(!PageLocked(page
));
3402 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
3405 * This silly early PAGE_DIRTY setting removes a race
3406 * due to the bad i386 page protection. But it's valid
3407 * for other architectures too.
3409 * Note that if FAULT_FLAG_WRITE is set, we either now have
3410 * an exclusive copy of the page, or this is a shared mapping,
3411 * so we can make it writable and dirty to avoid having to
3412 * handle that later.
3414 /* Only go through if we didn't race with anybody else... */
3415 if (likely(pte_same(*page_table
, orig_pte
))) {
3416 flush_icache_page(vma
, page
);
3417 entry
= mk_pte(page
, vma
->vm_page_prot
);
3418 if (flags
& FAULT_FLAG_WRITE
)
3419 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
3420 else if (pte_file(orig_pte
) && pte_file_soft_dirty(orig_pte
))
3421 pte_mksoft_dirty(entry
);
3423 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
3424 page_add_new_anon_rmap(page
, vma
, address
);
3426 inc_mm_counter_fast(mm
, MM_FILEPAGES
);
3427 page_add_file_rmap(page
);
3428 if (flags
& FAULT_FLAG_WRITE
) {
3430 get_page(dirty_page
);
3433 set_pte_at(mm
, address
, page_table
, entry
);
3435 /* no need to invalidate: a not-present page won't be cached */
3436 update_mmu_cache(vma
, address
, page_table
);
3439 mem_cgroup_uncharge_page(cow_page
);
3441 page_cache_release(page
);
3443 anon
= 1; /* no anon but release faulted_page */
3446 pte_unmap_unlock(page_table
, ptl
);
3449 struct address_space
*mapping
= page
->mapping
;
3452 if (set_page_dirty(dirty_page
))
3454 unlock_page(dirty_page
);
3455 put_page(dirty_page
);
3456 if ((dirtied
|| page_mkwrite
) && mapping
) {
3458 * Some device drivers do not set page.mapping but still
3461 balance_dirty_pages_ratelimited(mapping
);
3464 /* file_update_time outside page_lock */
3465 if (vma
->vm_file
&& !page_mkwrite
)
3466 file_update_time(vma
->vm_file
);
3468 unlock_page(vmf
.page
);
3470 page_cache_release(vmf
.page
);
3476 page_cache_release(page
);
3479 /* fs's fault handler get error */
3481 mem_cgroup_uncharge_page(cow_page
);
3482 page_cache_release(cow_page
);
3487 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3488 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
3489 unsigned int flags
, pte_t orig_pte
)
3491 pgoff_t pgoff
= (((address
& PAGE_MASK
)
3492 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
3494 pte_unmap(page_table
);
3495 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
3499 * Fault of a previously existing named mapping. Repopulate the pte
3500 * from the encoded file_pte if possible. This enables swappable
3503 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3504 * but allow concurrent faults), and pte mapped but not yet locked.
3505 * We return with mmap_sem still held, but pte unmapped and unlocked.
3507 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3508 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
3509 unsigned int flags
, pte_t orig_pte
)
3513 flags
|= FAULT_FLAG_NONLINEAR
;
3515 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
3518 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
3520 * Page table corrupted: show pte and kill process.
3522 print_bad_pte(vma
, address
, orig_pte
, NULL
);
3523 return VM_FAULT_SIGBUS
;
3526 pgoff
= pte_to_pgoff(orig_pte
);
3527 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
3530 int numa_migrate_prep(struct page
*page
, struct vm_area_struct
*vma
,
3531 unsigned long addr
, int page_nid
,
3536 count_vm_numa_event(NUMA_HINT_FAULTS
);
3537 if (page_nid
== numa_node_id()) {
3538 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL
);
3539 *flags
|= TNF_FAULT_LOCAL
;
3542 return mpol_misplaced(page
, vma
, addr
);
3545 int do_numa_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3546 unsigned long addr
, pte_t pte
, pte_t
*ptep
, pmd_t
*pmd
)
3548 struct page
*page
= NULL
;
3553 bool migrated
= false;
3557 * The "pte" at this point cannot be used safely without
3558 * validation through pte_unmap_same(). It's of NUMA type but
3559 * the pfn may be screwed if the read is non atomic.
3561 * ptep_modify_prot_start is not called as this is clearing
3562 * the _PAGE_NUMA bit and it is not really expected that there
3563 * would be concurrent hardware modifications to the PTE.
3565 ptl
= pte_lockptr(mm
, pmd
);
3567 if (unlikely(!pte_same(*ptep
, pte
))) {
3568 pte_unmap_unlock(ptep
, ptl
);
3572 pte
= pte_mknonnuma(pte
);
3573 set_pte_at(mm
, addr
, ptep
, pte
);
3574 update_mmu_cache(vma
, addr
, ptep
);
3576 page
= vm_normal_page(vma
, addr
, pte
);
3578 pte_unmap_unlock(ptep
, ptl
);
3581 BUG_ON(is_zero_pfn(page_to_pfn(page
)));
3584 * Avoid grouping on DSO/COW pages in specific and RO pages
3585 * in general, RO pages shouldn't hurt as much anyway since
3586 * they can be in shared cache state.
3588 if (!pte_write(pte
))
3589 flags
|= TNF_NO_GROUP
;
3592 * Flag if the page is shared between multiple address spaces. This
3593 * is later used when determining whether to group tasks together
3595 if (page_mapcount(page
) > 1 && (vma
->vm_flags
& VM_SHARED
))
3596 flags
|= TNF_SHARED
;
3598 last_cpupid
= page_cpupid_last(page
);
3599 page_nid
= page_to_nid(page
);
3600 target_nid
= numa_migrate_prep(page
, vma
, addr
, page_nid
, &flags
);
3601 pte_unmap_unlock(ptep
, ptl
);
3602 if (target_nid
== -1) {
3607 /* Migrate to the requested node */
3608 migrated
= migrate_misplaced_page(page
, vma
, target_nid
);
3610 page_nid
= target_nid
;
3611 flags
|= TNF_MIGRATED
;
3616 task_numa_fault(last_cpupid
, page_nid
, 1, flags
);
3621 * These routines also need to handle stuff like marking pages dirty
3622 * and/or accessed for architectures that don't do it in hardware (most
3623 * RISC architectures). The early dirtying is also good on the i386.
3625 * There is also a hook called "update_mmu_cache()" that architectures
3626 * with external mmu caches can use to update those (ie the Sparc or
3627 * PowerPC hashed page tables that act as extended TLBs).
3629 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3630 * but allow concurrent faults), and pte mapped but not yet locked.
3631 * We return with mmap_sem still held, but pte unmapped and unlocked.
3633 static int handle_pte_fault(struct mm_struct
*mm
,
3634 struct vm_area_struct
*vma
, unsigned long address
,
3635 pte_t
*pte
, pmd_t
*pmd
, unsigned int flags
)
3641 if (!pte_present(entry
)) {
3642 if (pte_none(entry
)) {
3644 if (likely(vma
->vm_ops
->fault
))
3645 return do_linear_fault(mm
, vma
, address
,
3646 pte
, pmd
, flags
, entry
);
3648 return do_anonymous_page(mm
, vma
, address
,
3651 if (pte_file(entry
))
3652 return do_nonlinear_fault(mm
, vma
, address
,
3653 pte
, pmd
, flags
, entry
);
3654 return do_swap_page(mm
, vma
, address
,
3655 pte
, pmd
, flags
, entry
);
3658 if (pte_numa(entry
))
3659 return do_numa_page(mm
, vma
, address
, entry
, pte
, pmd
);
3661 ptl
= pte_lockptr(mm
, pmd
);
3663 if (unlikely(!pte_same(*pte
, entry
)))
3665 if (flags
& FAULT_FLAG_WRITE
) {
3666 if (!pte_write(entry
))
3667 return do_wp_page(mm
, vma
, address
,
3668 pte
, pmd
, ptl
, entry
);
3669 entry
= pte_mkdirty(entry
);
3671 entry
= pte_mkyoung(entry
);
3672 if (ptep_set_access_flags(vma
, address
, pte
, entry
, flags
& FAULT_FLAG_WRITE
)) {
3673 update_mmu_cache(vma
, address
, pte
);
3676 * This is needed only for protection faults but the arch code
3677 * is not yet telling us if this is a protection fault or not.
3678 * This still avoids useless tlb flushes for .text page faults
3681 if (flags
& FAULT_FLAG_WRITE
)
3682 flush_tlb_fix_spurious_fault(vma
, address
);
3685 pte_unmap_unlock(pte
, ptl
);
3690 * By the time we get here, we already hold the mm semaphore
3692 static int __handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3693 unsigned long address
, unsigned int flags
)
3700 if (unlikely(is_vm_hugetlb_page(vma
)))
3701 return hugetlb_fault(mm
, vma
, address
, flags
);
3704 pgd
= pgd_offset(mm
, address
);
3705 pud
= pud_alloc(mm
, pgd
, address
);
3707 return VM_FAULT_OOM
;
3708 pmd
= pmd_alloc(mm
, pud
, address
);
3710 return VM_FAULT_OOM
;
3711 if (pmd_none(*pmd
) && transparent_hugepage_enabled(vma
)) {
3712 int ret
= VM_FAULT_FALLBACK
;
3714 ret
= do_huge_pmd_anonymous_page(mm
, vma
, address
,
3716 if (!(ret
& VM_FAULT_FALLBACK
))
3719 pmd_t orig_pmd
= *pmd
;
3723 if (pmd_trans_huge(orig_pmd
)) {
3724 unsigned int dirty
= flags
& FAULT_FLAG_WRITE
;
3727 * If the pmd is splitting, return and retry the
3728 * the fault. Alternative: wait until the split
3729 * is done, and goto retry.
3731 if (pmd_trans_splitting(orig_pmd
))
3734 if (pmd_numa(orig_pmd
))
3735 return do_huge_pmd_numa_page(mm
, vma
, address
,
3738 if (dirty
&& !pmd_write(orig_pmd
)) {
3739 ret
= do_huge_pmd_wp_page(mm
, vma
, address
, pmd
,
3742 * If COW results in an oom, the huge pmd will
3743 * have been split, so retry the fault on the
3744 * pte for a smaller charge.
3746 if (unlikely(ret
& VM_FAULT_OOM
))
3750 huge_pmd_set_accessed(mm
, vma
, address
, pmd
,
3758 /* THP should already have been handled */
3759 BUG_ON(pmd_numa(*pmd
));
3762 * Use __pte_alloc instead of pte_alloc_map, because we can't
3763 * run pte_offset_map on the pmd, if an huge pmd could
3764 * materialize from under us from a different thread.
3766 if (unlikely(pmd_none(*pmd
)) &&
3767 unlikely(__pte_alloc(mm
, vma
, pmd
, address
)))
3768 return VM_FAULT_OOM
;
3769 /* if an huge pmd materialized from under us just retry later */
3770 if (unlikely(pmd_trans_huge(*pmd
)))
3773 * A regular pmd is established and it can't morph into a huge pmd
3774 * from under us anymore at this point because we hold the mmap_sem
3775 * read mode and khugepaged takes it in write mode. So now it's
3776 * safe to run pte_offset_map().
3778 pte
= pte_offset_map(pmd
, address
);
3780 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, flags
);
3783 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
3784 unsigned long address
, unsigned int flags
)
3788 __set_current_state(TASK_RUNNING
);
3790 count_vm_event(PGFAULT
);
3791 mem_cgroup_count_vm_event(mm
, PGFAULT
);
3793 /* do counter updates before entering really critical section. */
3794 check_sync_rss_stat(current
);
3797 * Enable the memcg OOM handling for faults triggered in user
3798 * space. Kernel faults are handled more gracefully.
3800 if (flags
& FAULT_FLAG_USER
)
3801 mem_cgroup_oom_enable();
3803 ret
= __handle_mm_fault(mm
, vma
, address
, flags
);
3805 if (flags
& FAULT_FLAG_USER
) {
3806 mem_cgroup_oom_disable();
3808 * The task may have entered a memcg OOM situation but
3809 * if the allocation error was handled gracefully (no
3810 * VM_FAULT_OOM), there is no need to kill anything.
3811 * Just clean up the OOM state peacefully.
3813 if (task_in_memcg_oom(current
) && !(ret
& VM_FAULT_OOM
))
3814 mem_cgroup_oom_synchronize(false);
3820 #ifndef __PAGETABLE_PUD_FOLDED
3822 * Allocate page upper directory.
3823 * We've already handled the fast-path in-line.
3825 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
3827 pud_t
*new = pud_alloc_one(mm
, address
);
3831 smp_wmb(); /* See comment in __pte_alloc */
3833 spin_lock(&mm
->page_table_lock
);
3834 if (pgd_present(*pgd
)) /* Another has populated it */
3837 pgd_populate(mm
, pgd
, new);
3838 spin_unlock(&mm
->page_table_lock
);
3841 #endif /* __PAGETABLE_PUD_FOLDED */
3843 #ifndef __PAGETABLE_PMD_FOLDED
3845 * Allocate page middle directory.
3846 * We've already handled the fast-path in-line.
3848 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
3850 pmd_t
*new = pmd_alloc_one(mm
, address
);
3854 smp_wmb(); /* See comment in __pte_alloc */
3856 spin_lock(&mm
->page_table_lock
);
3857 #ifndef __ARCH_HAS_4LEVEL_HACK
3858 if (pud_present(*pud
)) /* Another has populated it */
3861 pud_populate(mm
, pud
, new);
3863 if (pgd_present(*pud
)) /* Another has populated it */
3866 pgd_populate(mm
, pud
, new);
3867 #endif /* __ARCH_HAS_4LEVEL_HACK */
3868 spin_unlock(&mm
->page_table_lock
);
3871 #endif /* __PAGETABLE_PMD_FOLDED */
3873 #if !defined(__HAVE_ARCH_GATE_AREA)
3875 #if defined(AT_SYSINFO_EHDR)
3876 static struct vm_area_struct gate_vma
;
3878 static int __init
gate_vma_init(void)
3880 gate_vma
.vm_mm
= NULL
;
3881 gate_vma
.vm_start
= FIXADDR_USER_START
;
3882 gate_vma
.vm_end
= FIXADDR_USER_END
;
3883 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
3884 gate_vma
.vm_page_prot
= __P101
;
3888 __initcall(gate_vma_init
);
3891 struct vm_area_struct
*get_gate_vma(struct mm_struct
*mm
)
3893 #ifdef AT_SYSINFO_EHDR
3900 int in_gate_area_no_mm(unsigned long addr
)
3902 #ifdef AT_SYSINFO_EHDR
3903 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
3909 #endif /* __HAVE_ARCH_GATE_AREA */
3911 static int __follow_pte(struct mm_struct
*mm
, unsigned long address
,
3912 pte_t
**ptepp
, spinlock_t
**ptlp
)
3919 pgd
= pgd_offset(mm
, address
);
3920 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
3923 pud
= pud_offset(pgd
, address
);
3924 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
3927 pmd
= pmd_offset(pud
, address
);
3928 VM_BUG_ON(pmd_trans_huge(*pmd
));
3929 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
3932 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3936 ptep
= pte_offset_map_lock(mm
, pmd
, address
, ptlp
);
3939 if (!pte_present(*ptep
))
3944 pte_unmap_unlock(ptep
, *ptlp
);
3949 static inline int follow_pte(struct mm_struct
*mm
, unsigned long address
,
3950 pte_t
**ptepp
, spinlock_t
**ptlp
)
3954 /* (void) is needed to make gcc happy */
3955 (void) __cond_lock(*ptlp
,
3956 !(res
= __follow_pte(mm
, address
, ptepp
, ptlp
)));
3961 * follow_pfn - look up PFN at a user virtual address
3962 * @vma: memory mapping
3963 * @address: user virtual address
3964 * @pfn: location to store found PFN
3966 * Only IO mappings and raw PFN mappings are allowed.
3968 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3970 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
3977 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3980 ret
= follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
);
3983 *pfn
= pte_pfn(*ptep
);
3984 pte_unmap_unlock(ptep
, ptl
);
3987 EXPORT_SYMBOL(follow_pfn
);
3989 #ifdef CONFIG_HAVE_IOREMAP_PROT
3990 int follow_phys(struct vm_area_struct
*vma
,
3991 unsigned long address
, unsigned int flags
,
3992 unsigned long *prot
, resource_size_t
*phys
)
3998 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
4001 if (follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
))
4005 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
4008 *prot
= pgprot_val(pte_pgprot(pte
));
4009 *phys
= (resource_size_t
)pte_pfn(pte
) << PAGE_SHIFT
;
4013 pte_unmap_unlock(ptep
, ptl
);
4018 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
4019 void *buf
, int len
, int write
)
4021 resource_size_t phys_addr
;
4022 unsigned long prot
= 0;
4023 void __iomem
*maddr
;
4024 int offset
= addr
& (PAGE_SIZE
-1);
4026 if (follow_phys(vma
, addr
, write
, &prot
, &phys_addr
))
4029 maddr
= ioremap_prot(phys_addr
, PAGE_SIZE
, prot
);
4031 memcpy_toio(maddr
+ offset
, buf
, len
);
4033 memcpy_fromio(buf
, maddr
+ offset
, len
);
4038 EXPORT_SYMBOL_GPL(generic_access_phys
);
4042 * Access another process' address space as given in mm. If non-NULL, use the
4043 * given task for page fault accounting.
4045 static int __access_remote_vm(struct task_struct
*tsk
, struct mm_struct
*mm
,
4046 unsigned long addr
, void *buf
, int len
, int write
)
4048 struct vm_area_struct
*vma
;
4049 void *old_buf
= buf
;
4051 down_read(&mm
->mmap_sem
);
4052 /* ignore errors, just check how much was successfully transferred */
4054 int bytes
, ret
, offset
;
4056 struct page
*page
= NULL
;
4058 ret
= get_user_pages(tsk
, mm
, addr
, 1,
4059 write
, 1, &page
, &vma
);
4062 * Check if this is a VM_IO | VM_PFNMAP VMA, which
4063 * we can access using slightly different code.
4065 #ifdef CONFIG_HAVE_IOREMAP_PROT
4066 vma
= find_vma(mm
, addr
);
4067 if (!vma
|| vma
->vm_start
> addr
)
4069 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
4070 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
4078 offset
= addr
& (PAGE_SIZE
-1);
4079 if (bytes
> PAGE_SIZE
-offset
)
4080 bytes
= PAGE_SIZE
-offset
;
4084 copy_to_user_page(vma
, page
, addr
,
4085 maddr
+ offset
, buf
, bytes
);
4086 set_page_dirty_lock(page
);
4088 copy_from_user_page(vma
, page
, addr
,
4089 buf
, maddr
+ offset
, bytes
);
4092 page_cache_release(page
);
4098 up_read(&mm
->mmap_sem
);
4100 return buf
- old_buf
;
4104 * access_remote_vm - access another process' address space
4105 * @mm: the mm_struct of the target address space
4106 * @addr: start address to access
4107 * @buf: source or destination buffer
4108 * @len: number of bytes to transfer
4109 * @write: whether the access is a write
4111 * The caller must hold a reference on @mm.
4113 int access_remote_vm(struct mm_struct
*mm
, unsigned long addr
,
4114 void *buf
, int len
, int write
)
4116 return __access_remote_vm(NULL
, mm
, addr
, buf
, len
, write
);
4120 * Access another process' address space.
4121 * Source/target buffer must be kernel space,
4122 * Do not walk the page table directly, use get_user_pages
4124 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
,
4125 void *buf
, int len
, int write
)
4127 struct mm_struct
*mm
;
4130 mm
= get_task_mm(tsk
);
4134 ret
= __access_remote_vm(tsk
, mm
, addr
, buf
, len
, write
);
4141 * Print the name of a VMA.
4143 void print_vma_addr(char *prefix
, unsigned long ip
)
4145 struct mm_struct
*mm
= current
->mm
;
4146 struct vm_area_struct
*vma
;
4149 * Do not print if we are in atomic
4150 * contexts (in exception stacks, etc.):
4152 if (preempt_count())
4155 down_read(&mm
->mmap_sem
);
4156 vma
= find_vma(mm
, ip
);
4157 if (vma
&& vma
->vm_file
) {
4158 struct file
*f
= vma
->vm_file
;
4159 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
4163 p
= d_path(&f
->f_path
, buf
, PAGE_SIZE
);
4166 printk("%s%s[%lx+%lx]", prefix
, kbasename(p
),
4168 vma
->vm_end
- vma
->vm_start
);
4169 free_page((unsigned long)buf
);
4172 up_read(&mm
->mmap_sem
);
4175 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
4176 void might_fault(void)
4179 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4180 * holding the mmap_sem, this is safe because kernel memory doesn't
4181 * get paged out, therefore we'll never actually fault, and the
4182 * below annotations will generate false positives.
4184 if (segment_eq(get_fs(), KERNEL_DS
))
4188 * it would be nicer only to annotate paths which are not under
4189 * pagefault_disable, however that requires a larger audit and
4190 * providing helpers like get_user_atomic.
4195 __might_sleep(__FILE__
, __LINE__
, 0);
4198 might_lock_read(¤t
->mm
->mmap_sem
);
4200 EXPORT_SYMBOL(might_fault
);
4203 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4204 static void clear_gigantic_page(struct page
*page
,
4206 unsigned int pages_per_huge_page
)
4209 struct page
*p
= page
;
4212 for (i
= 0; i
< pages_per_huge_page
;
4213 i
++, p
= mem_map_next(p
, page
, i
)) {
4215 clear_user_highpage(p
, addr
+ i
* PAGE_SIZE
);
4218 void clear_huge_page(struct page
*page
,
4219 unsigned long addr
, unsigned int pages_per_huge_page
)
4223 if (unlikely(pages_per_huge_page
> MAX_ORDER_NR_PAGES
)) {
4224 clear_gigantic_page(page
, addr
, pages_per_huge_page
);
4229 for (i
= 0; i
< pages_per_huge_page
; i
++) {
4231 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
4235 static void copy_user_gigantic_page(struct page
*dst
, struct page
*src
,
4237 struct vm_area_struct
*vma
,
4238 unsigned int pages_per_huge_page
)
4241 struct page
*dst_base
= dst
;
4242 struct page
*src_base
= src
;
4244 for (i
= 0; i
< pages_per_huge_page
; ) {
4246 copy_user_highpage(dst
, src
, addr
+ i
*PAGE_SIZE
, vma
);
4249 dst
= mem_map_next(dst
, dst_base
, i
);
4250 src
= mem_map_next(src
, src_base
, i
);
4254 void copy_user_huge_page(struct page
*dst
, struct page
*src
,
4255 unsigned long addr
, struct vm_area_struct
*vma
,
4256 unsigned int pages_per_huge_page
)
4260 if (unlikely(pages_per_huge_page
> MAX_ORDER_NR_PAGES
)) {
4261 copy_user_gigantic_page(dst
, src
, addr
, vma
,
4262 pages_per_huge_page
);
4267 for (i
= 0; i
< pages_per_huge_page
; i
++) {
4269 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
4272 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
4274 #if USE_SPLIT_PTE_PTLOCKS && BLOATED_SPINLOCKS
4275 bool ptlock_alloc(struct page
*page
)
4279 ptl
= kmalloc(sizeof(spinlock_t
), GFP_KERNEL
);
4286 void ptlock_free(struct page
*page
)