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/rmap.h>
49 #include <linux/module.h>
50 #include <linux/delayacct.h>
51 #include <linux/init.h>
52 #include <linux/writeback.h>
54 #include <asm/pgalloc.h>
55 #include <asm/uaccess.h>
57 #include <asm/tlbflush.h>
58 #include <asm/pgtable.h>
60 #include <linux/swapops.h>
61 #include <linux/elf.h>
63 #ifndef CONFIG_NEED_MULTIPLE_NODES
64 /* use the per-pgdat data instead for discontigmem - mbligh */
65 unsigned long max_mapnr
;
68 EXPORT_SYMBOL(max_mapnr
);
69 EXPORT_SYMBOL(mem_map
);
72 unsigned long num_physpages
;
74 * A number of key systems in x86 including ioremap() rely on the assumption
75 * that high_memory defines the upper bound on direct map memory, then end
76 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
77 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
81 unsigned long vmalloc_earlyreserve
;
83 EXPORT_SYMBOL(num_physpages
);
84 EXPORT_SYMBOL(high_memory
);
85 EXPORT_SYMBOL(vmalloc_earlyreserve
);
87 int randomize_va_space __read_mostly
= 1;
89 static int __init
disable_randmaps(char *s
)
91 randomize_va_space
= 0;
94 __setup("norandmaps", disable_randmaps
);
98 * If a p?d_bad entry is found while walking page tables, report
99 * the error, before resetting entry to p?d_none. Usually (but
100 * very seldom) called out from the p?d_none_or_clear_bad macros.
103 void pgd_clear_bad(pgd_t
*pgd
)
109 void pud_clear_bad(pud_t
*pud
)
115 void pmd_clear_bad(pmd_t
*pmd
)
122 * Note: this doesn't free the actual pages themselves. That
123 * has been handled earlier when unmapping all the memory regions.
125 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
)
127 struct page
*page
= pmd_page(*pmd
);
129 pte_lock_deinit(page
);
130 pte_free_tlb(tlb
, page
);
131 dec_zone_page_state(page
, NR_PAGETABLE
);
135 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
136 unsigned long addr
, unsigned long end
,
137 unsigned long floor
, unsigned long ceiling
)
144 pmd
= pmd_offset(pud
, addr
);
146 next
= pmd_addr_end(addr
, end
);
147 if (pmd_none_or_clear_bad(pmd
))
149 free_pte_range(tlb
, pmd
);
150 } while (pmd
++, addr
= next
, addr
!= end
);
160 if (end
- 1 > ceiling
- 1)
163 pmd
= pmd_offset(pud
, start
);
165 pmd_free_tlb(tlb
, pmd
);
168 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
169 unsigned long addr
, unsigned long end
,
170 unsigned long floor
, unsigned long ceiling
)
177 pud
= pud_offset(pgd
, addr
);
179 next
= pud_addr_end(addr
, end
);
180 if (pud_none_or_clear_bad(pud
))
182 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
183 } while (pud
++, addr
= next
, addr
!= end
);
189 ceiling
&= PGDIR_MASK
;
193 if (end
- 1 > ceiling
- 1)
196 pud
= pud_offset(pgd
, start
);
198 pud_free_tlb(tlb
, pud
);
202 * This function frees user-level page tables of a process.
204 * Must be called with pagetable lock held.
206 void free_pgd_range(struct mmu_gather
**tlb
,
207 unsigned long addr
, unsigned long end
,
208 unsigned long floor
, unsigned long ceiling
)
215 * The next few lines have given us lots of grief...
217 * Why are we testing PMD* at this top level? Because often
218 * there will be no work to do at all, and we'd prefer not to
219 * go all the way down to the bottom just to discover that.
221 * Why all these "- 1"s? Because 0 represents both the bottom
222 * of the address space and the top of it (using -1 for the
223 * top wouldn't help much: the masks would do the wrong thing).
224 * The rule is that addr 0 and floor 0 refer to the bottom of
225 * the address space, but end 0 and ceiling 0 refer to the top
226 * Comparisons need to use "end - 1" and "ceiling - 1" (though
227 * that end 0 case should be mythical).
229 * Wherever addr is brought up or ceiling brought down, we must
230 * be careful to reject "the opposite 0" before it confuses the
231 * subsequent tests. But what about where end is brought down
232 * by PMD_SIZE below? no, end can't go down to 0 there.
234 * Whereas we round start (addr) and ceiling down, by different
235 * masks at different levels, in order to test whether a table
236 * now has no other vmas using it, so can be freed, we don't
237 * bother to round floor or end up - the tests don't need that.
251 if (end
- 1 > ceiling
- 1)
257 pgd
= pgd_offset((*tlb
)->mm
, addr
);
259 next
= pgd_addr_end(addr
, end
);
260 if (pgd_none_or_clear_bad(pgd
))
262 free_pud_range(*tlb
, pgd
, addr
, next
, floor
, ceiling
);
263 } while (pgd
++, addr
= next
, addr
!= end
);
266 flush_tlb_pgtables((*tlb
)->mm
, start
, end
);
269 void free_pgtables(struct mmu_gather
**tlb
, struct vm_area_struct
*vma
,
270 unsigned long floor
, unsigned long ceiling
)
273 struct vm_area_struct
*next
= vma
->vm_next
;
274 unsigned long addr
= vma
->vm_start
;
277 * Hide vma from rmap and vmtruncate before freeing pgtables
279 anon_vma_unlink(vma
);
280 unlink_file_vma(vma
);
282 if (is_vm_hugetlb_page(vma
)) {
283 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
284 floor
, next
? next
->vm_start
: ceiling
);
287 * Optimization: gather nearby vmas into one call down
289 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
290 && !is_vm_hugetlb_page(next
)) {
293 anon_vma_unlink(vma
);
294 unlink_file_vma(vma
);
296 free_pgd_range(tlb
, addr
, vma
->vm_end
,
297 floor
, next
? next
->vm_start
: ceiling
);
303 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
305 struct page
*new = pte_alloc_one(mm
, address
);
310 spin_lock(&mm
->page_table_lock
);
311 if (pmd_present(*pmd
)) { /* Another has populated it */
312 pte_lock_deinit(new);
316 inc_zone_page_state(new, NR_PAGETABLE
);
317 pmd_populate(mm
, pmd
, new);
319 spin_unlock(&mm
->page_table_lock
);
323 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
325 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
329 spin_lock(&init_mm
.page_table_lock
);
330 if (pmd_present(*pmd
)) /* Another has populated it */
331 pte_free_kernel(new);
333 pmd_populate_kernel(&init_mm
, pmd
, new);
334 spin_unlock(&init_mm
.page_table_lock
);
338 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
341 add_mm_counter(mm
, file_rss
, file_rss
);
343 add_mm_counter(mm
, anon_rss
, anon_rss
);
347 * This function is called to print an error when a bad pte
348 * is found. For example, we might have a PFN-mapped pte in
349 * a region that doesn't allow it.
351 * The calling function must still handle the error.
353 void print_bad_pte(struct vm_area_struct
*vma
, pte_t pte
, unsigned long vaddr
)
355 printk(KERN_ERR
"Bad pte = %08llx, process = %s, "
356 "vm_flags = %lx, vaddr = %lx\n",
357 (long long)pte_val(pte
),
358 (vma
->vm_mm
== current
->mm
? current
->comm
: "???"),
359 vma
->vm_flags
, vaddr
);
363 static inline int is_cow_mapping(unsigned int flags
)
365 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
369 * This function gets the "struct page" associated with a pte.
371 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
372 * will have each page table entry just pointing to a raw page frame
373 * number, and as far as the VM layer is concerned, those do not have
374 * pages associated with them - even if the PFN might point to memory
375 * that otherwise is perfectly fine and has a "struct page".
377 * The way we recognize those mappings is through the rules set up
378 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
379 * and the vm_pgoff will point to the first PFN mapped: thus every
380 * page that is a raw mapping will always honor the rule
382 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
384 * and if that isn't true, the page has been COW'ed (in which case it
385 * _does_ have a "struct page" associated with it even if it is in a
388 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
, pte_t pte
)
390 unsigned long pfn
= pte_pfn(pte
);
392 if (unlikely(vma
->vm_flags
& VM_PFNMAP
)) {
393 unsigned long off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
394 if (pfn
== vma
->vm_pgoff
+ off
)
396 if (!is_cow_mapping(vma
->vm_flags
))
401 * Add some anal sanity checks for now. Eventually,
402 * we should just do "return pfn_to_page(pfn)", but
403 * in the meantime we check that we get a valid pfn,
404 * and that the resulting page looks ok.
406 if (unlikely(!pfn_valid(pfn
))) {
407 print_bad_pte(vma
, pte
, addr
);
412 * NOTE! We still have PageReserved() pages in the page
415 * The PAGE_ZERO() pages and various VDSO mappings can
416 * cause them to exist.
418 return pfn_to_page(pfn
);
422 * copy one vm_area from one task to the other. Assumes the page tables
423 * already present in the new task to be cleared in the whole range
424 * covered by this vma.
428 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
429 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
430 unsigned long addr
, int *rss
)
432 unsigned long vm_flags
= vma
->vm_flags
;
433 pte_t pte
= *src_pte
;
436 /* pte contains position in swap or file, so copy. */
437 if (unlikely(!pte_present(pte
))) {
438 if (!pte_file(pte
)) {
439 swp_entry_t entry
= pte_to_swp_entry(pte
);
441 swap_duplicate(entry
);
442 /* make sure dst_mm is on swapoff's mmlist. */
443 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
444 spin_lock(&mmlist_lock
);
445 if (list_empty(&dst_mm
->mmlist
))
446 list_add(&dst_mm
->mmlist
,
448 spin_unlock(&mmlist_lock
);
450 if (is_write_migration_entry(entry
) &&
451 is_cow_mapping(vm_flags
)) {
453 * COW mappings require pages in both parent
454 * and child to be set to read.
456 make_migration_entry_read(&entry
);
457 pte
= swp_entry_to_pte(entry
);
458 set_pte_at(src_mm
, addr
, src_pte
, pte
);
465 * If it's a COW mapping, write protect it both
466 * in the parent and the child
468 if (is_cow_mapping(vm_flags
)) {
469 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
470 pte
= pte_wrprotect(pte
);
474 * If it's a shared mapping, mark it clean in
477 if (vm_flags
& VM_SHARED
)
478 pte
= pte_mkclean(pte
);
479 pte
= pte_mkold(pte
);
481 page
= vm_normal_page(vma
, addr
, pte
);
484 page_dup_rmap(page
, vma
, addr
);
485 rss
[!!PageAnon(page
)]++;
489 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
492 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
493 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
494 unsigned long addr
, unsigned long end
)
496 pte_t
*src_pte
, *dst_pte
;
497 spinlock_t
*src_ptl
, *dst_ptl
;
503 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
506 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
507 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
508 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
509 arch_enter_lazy_mmu_mode();
513 * We are holding two locks at this point - either of them
514 * could generate latencies in another task on another CPU.
516 if (progress
>= 32) {
518 if (need_resched() ||
519 need_lockbreak(src_ptl
) ||
520 need_lockbreak(dst_ptl
))
523 if (pte_none(*src_pte
)) {
527 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
529 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
531 arch_leave_lazy_mmu_mode();
532 spin_unlock(src_ptl
);
533 pte_unmap_nested(src_pte
- 1);
534 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
535 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
542 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
543 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
544 unsigned long addr
, unsigned long end
)
546 pmd_t
*src_pmd
, *dst_pmd
;
549 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
552 src_pmd
= pmd_offset(src_pud
, addr
);
554 next
= pmd_addr_end(addr
, end
);
555 if (pmd_none_or_clear_bad(src_pmd
))
557 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
560 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
564 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
565 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
566 unsigned long addr
, unsigned long end
)
568 pud_t
*src_pud
, *dst_pud
;
571 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
574 src_pud
= pud_offset(src_pgd
, addr
);
576 next
= pud_addr_end(addr
, end
);
577 if (pud_none_or_clear_bad(src_pud
))
579 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
582 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
586 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
587 struct vm_area_struct
*vma
)
589 pgd_t
*src_pgd
, *dst_pgd
;
591 unsigned long addr
= vma
->vm_start
;
592 unsigned long end
= vma
->vm_end
;
595 * Don't copy ptes where a page fault will fill them correctly.
596 * Fork becomes much lighter when there are big shared or private
597 * readonly mappings. The tradeoff is that copy_page_range is more
598 * efficient than faulting.
600 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_PFNMAP
|VM_INSERTPAGE
))) {
605 if (is_vm_hugetlb_page(vma
))
606 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
608 dst_pgd
= pgd_offset(dst_mm
, addr
);
609 src_pgd
= pgd_offset(src_mm
, addr
);
611 next
= pgd_addr_end(addr
, end
);
612 if (pgd_none_or_clear_bad(src_pgd
))
614 if (copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
617 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
621 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
622 struct vm_area_struct
*vma
, pmd_t
*pmd
,
623 unsigned long addr
, unsigned long end
,
624 long *zap_work
, struct zap_details
*details
)
626 struct mm_struct
*mm
= tlb
->mm
;
632 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
633 arch_enter_lazy_mmu_mode();
636 if (pte_none(ptent
)) {
641 (*zap_work
) -= PAGE_SIZE
;
643 if (pte_present(ptent
)) {
646 page
= vm_normal_page(vma
, addr
, ptent
);
647 if (unlikely(details
) && page
) {
649 * unmap_shared_mapping_pages() wants to
650 * invalidate cache without truncating:
651 * unmap shared but keep private pages.
653 if (details
->check_mapping
&&
654 details
->check_mapping
!= page
->mapping
)
657 * Each page->index must be checked when
658 * invalidating or truncating nonlinear.
660 if (details
->nonlinear_vma
&&
661 (page
->index
< details
->first_index
||
662 page
->index
> details
->last_index
))
665 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
667 tlb_remove_tlb_entry(tlb
, pte
, addr
);
670 if (unlikely(details
) && details
->nonlinear_vma
671 && linear_page_index(details
->nonlinear_vma
,
672 addr
) != page
->index
)
673 set_pte_at(mm
, addr
, pte
,
674 pgoff_to_pte(page
->index
));
678 if (pte_dirty(ptent
))
679 set_page_dirty(page
);
680 if (pte_young(ptent
))
681 SetPageReferenced(page
);
684 page_remove_rmap(page
, vma
);
685 tlb_remove_page(tlb
, page
);
689 * If details->check_mapping, we leave swap entries;
690 * if details->nonlinear_vma, we leave file entries.
692 if (unlikely(details
))
694 if (!pte_file(ptent
))
695 free_swap_and_cache(pte_to_swp_entry(ptent
));
696 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
697 } while (pte
++, addr
+= PAGE_SIZE
, (addr
!= end
&& *zap_work
> 0));
699 add_mm_rss(mm
, file_rss
, anon_rss
);
700 arch_leave_lazy_mmu_mode();
701 pte_unmap_unlock(pte
- 1, ptl
);
706 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
707 struct vm_area_struct
*vma
, pud_t
*pud
,
708 unsigned long addr
, unsigned long end
,
709 long *zap_work
, struct zap_details
*details
)
714 pmd
= pmd_offset(pud
, addr
);
716 next
= pmd_addr_end(addr
, end
);
717 if (pmd_none_or_clear_bad(pmd
)) {
721 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
,
723 } while (pmd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
728 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
729 struct vm_area_struct
*vma
, pgd_t
*pgd
,
730 unsigned long addr
, unsigned long end
,
731 long *zap_work
, struct zap_details
*details
)
736 pud
= pud_offset(pgd
, addr
);
738 next
= pud_addr_end(addr
, end
);
739 if (pud_none_or_clear_bad(pud
)) {
743 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
,
745 } while (pud
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
750 static unsigned long unmap_page_range(struct mmu_gather
*tlb
,
751 struct vm_area_struct
*vma
,
752 unsigned long addr
, unsigned long end
,
753 long *zap_work
, struct zap_details
*details
)
758 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
762 tlb_start_vma(tlb
, vma
);
763 pgd
= pgd_offset(vma
->vm_mm
, addr
);
765 next
= pgd_addr_end(addr
, end
);
766 if (pgd_none_or_clear_bad(pgd
)) {
770 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
,
772 } while (pgd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
773 tlb_end_vma(tlb
, vma
);
778 #ifdef CONFIG_PREEMPT
779 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
781 /* No preempt: go for improved straight-line efficiency */
782 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
786 * unmap_vmas - unmap a range of memory covered by a list of vma's
787 * @tlbp: address of the caller's struct mmu_gather
788 * @vma: the starting vma
789 * @start_addr: virtual address at which to start unmapping
790 * @end_addr: virtual address at which to end unmapping
791 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
792 * @details: details of nonlinear truncation or shared cache invalidation
794 * Returns the end address of the unmapping (restart addr if interrupted).
796 * Unmap all pages in the vma list.
798 * We aim to not hold locks for too long (for scheduling latency reasons).
799 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
800 * return the ending mmu_gather to the caller.
802 * Only addresses between `start' and `end' will be unmapped.
804 * The VMA list must be sorted in ascending virtual address order.
806 * unmap_vmas() assumes that the caller will flush the whole unmapped address
807 * range after unmap_vmas() returns. So the only responsibility here is to
808 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
809 * drops the lock and schedules.
811 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
812 struct vm_area_struct
*vma
, unsigned long start_addr
,
813 unsigned long end_addr
, unsigned long *nr_accounted
,
814 struct zap_details
*details
)
816 long zap_work
= ZAP_BLOCK_SIZE
;
817 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
818 int tlb_start_valid
= 0;
819 unsigned long start
= start_addr
;
820 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
821 int fullmm
= (*tlbp
)->fullmm
;
823 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
826 start
= max(vma
->vm_start
, start_addr
);
827 if (start
>= vma
->vm_end
)
829 end
= min(vma
->vm_end
, end_addr
);
830 if (end
<= vma
->vm_start
)
833 if (vma
->vm_flags
& VM_ACCOUNT
)
834 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
836 while (start
!= end
) {
837 if (!tlb_start_valid
) {
842 if (unlikely(is_vm_hugetlb_page(vma
))) {
843 unmap_hugepage_range(vma
, start
, end
);
844 zap_work
-= (end
- start
) /
845 (HPAGE_SIZE
/ PAGE_SIZE
);
848 start
= unmap_page_range(*tlbp
, vma
,
849 start
, end
, &zap_work
, details
);
852 BUG_ON(start
!= end
);
856 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
858 if (need_resched() ||
859 (i_mmap_lock
&& need_lockbreak(i_mmap_lock
))) {
867 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
869 zap_work
= ZAP_BLOCK_SIZE
;
873 return start
; /* which is now the end (or restart) address */
877 * zap_page_range - remove user pages in a given range
878 * @vma: vm_area_struct holding the applicable pages
879 * @address: starting address of pages to zap
880 * @size: number of bytes to zap
881 * @details: details of nonlinear truncation or shared cache invalidation
883 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
884 unsigned long size
, struct zap_details
*details
)
886 struct mm_struct
*mm
= vma
->vm_mm
;
887 struct mmu_gather
*tlb
;
888 unsigned long end
= address
+ size
;
889 unsigned long nr_accounted
= 0;
892 tlb
= tlb_gather_mmu(mm
, 0);
893 update_hiwater_rss(mm
);
894 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
896 tlb_finish_mmu(tlb
, address
, end
);
901 * Do a quick page-table lookup for a single page.
903 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
912 struct mm_struct
*mm
= vma
->vm_mm
;
914 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
916 BUG_ON(flags
& FOLL_GET
);
921 pgd
= pgd_offset(mm
, address
);
922 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
925 pud
= pud_offset(pgd
, address
);
926 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
929 pmd
= pmd_offset(pud
, address
);
930 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
933 if (pmd_huge(*pmd
)) {
934 BUG_ON(flags
& FOLL_GET
);
935 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
939 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
944 if (!pte_present(pte
))
946 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
948 page
= vm_normal_page(vma
, address
, pte
);
952 if (flags
& FOLL_GET
)
954 if (flags
& FOLL_TOUCH
) {
955 if ((flags
& FOLL_WRITE
) &&
956 !pte_dirty(pte
) && !PageDirty(page
))
957 set_page_dirty(page
);
958 mark_page_accessed(page
);
961 pte_unmap_unlock(ptep
, ptl
);
967 * When core dumping an enormous anonymous area that nobody
968 * has touched so far, we don't want to allocate page tables.
970 if (flags
& FOLL_ANON
) {
971 page
= ZERO_PAGE(address
);
972 if (flags
& FOLL_GET
)
974 BUG_ON(flags
& FOLL_WRITE
);
979 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
980 unsigned long start
, int len
, int write
, int force
,
981 struct page
**pages
, struct vm_area_struct
**vmas
)
984 unsigned int vm_flags
;
989 * Require read or write permissions.
990 * If 'force' is set, we only require the "MAY" flags.
992 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
993 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
997 struct vm_area_struct
*vma
;
998 unsigned int foll_flags
;
1000 vma
= find_extend_vma(mm
, start
);
1001 if (!vma
&& in_gate_area(tsk
, start
)) {
1002 unsigned long pg
= start
& PAGE_MASK
;
1003 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1008 if (write
) /* user gate pages are read-only */
1009 return i
? : -EFAULT
;
1011 pgd
= pgd_offset_k(pg
);
1013 pgd
= pgd_offset_gate(mm
, pg
);
1014 BUG_ON(pgd_none(*pgd
));
1015 pud
= pud_offset(pgd
, pg
);
1016 BUG_ON(pud_none(*pud
));
1017 pmd
= pmd_offset(pud
, pg
);
1019 return i
? : -EFAULT
;
1020 pte
= pte_offset_map(pmd
, pg
);
1021 if (pte_none(*pte
)) {
1023 return i
? : -EFAULT
;
1026 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1040 if (!vma
|| (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
))
1041 || !(vm_flags
& vma
->vm_flags
))
1042 return i
? : -EFAULT
;
1044 if (is_vm_hugetlb_page(vma
)) {
1045 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1050 foll_flags
= FOLL_TOUCH
;
1052 foll_flags
|= FOLL_GET
;
1053 if (!write
&& !(vma
->vm_flags
& VM_LOCKED
) &&
1054 (!vma
->vm_ops
|| !vma
->vm_ops
->nopage
))
1055 foll_flags
|= FOLL_ANON
;
1061 foll_flags
|= FOLL_WRITE
;
1064 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1066 ret
= __handle_mm_fault(mm
, vma
, start
,
1067 foll_flags
& FOLL_WRITE
);
1069 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1070 * broken COW when necessary, even if maybe_mkwrite
1071 * decided not to set pte_write. We can thus safely do
1072 * subsequent page lookups as if they were reads.
1074 if (ret
& VM_FAULT_WRITE
)
1075 foll_flags
&= ~FOLL_WRITE
;
1077 switch (ret
& ~VM_FAULT_WRITE
) {
1078 case VM_FAULT_MINOR
:
1081 case VM_FAULT_MAJOR
:
1084 case VM_FAULT_SIGBUS
:
1085 return i
? i
: -EFAULT
;
1087 return i
? i
: -ENOMEM
;
1096 flush_anon_page(vma
, page
, start
);
1097 flush_dcache_page(page
);
1104 } while (len
&& start
< vma
->vm_end
);
1108 EXPORT_SYMBOL(get_user_pages
);
1110 static int zeromap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1111 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1117 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1120 arch_enter_lazy_mmu_mode();
1122 struct page
*page
= ZERO_PAGE(addr
);
1123 pte_t zero_pte
= pte_wrprotect(mk_pte(page
, prot
));
1125 if (unlikely(!pte_none(*pte
))) {
1130 page_cache_get(page
);
1131 page_add_file_rmap(page
);
1132 inc_mm_counter(mm
, file_rss
);
1133 set_pte_at(mm
, addr
, pte
, zero_pte
);
1134 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1135 arch_leave_lazy_mmu_mode();
1136 pte_unmap_unlock(pte
- 1, ptl
);
1140 static inline int zeromap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1141 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1147 pmd
= pmd_alloc(mm
, pud
, addr
);
1151 next
= pmd_addr_end(addr
, end
);
1152 err
= zeromap_pte_range(mm
, pmd
, addr
, next
, prot
);
1155 } while (pmd
++, addr
= next
, addr
!= end
);
1159 static inline int zeromap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1160 unsigned long addr
, unsigned long end
, pgprot_t prot
)
1166 pud
= pud_alloc(mm
, pgd
, addr
);
1170 next
= pud_addr_end(addr
, end
);
1171 err
= zeromap_pmd_range(mm
, pud
, addr
, next
, prot
);
1174 } while (pud
++, addr
= next
, addr
!= end
);
1178 int zeromap_page_range(struct vm_area_struct
*vma
,
1179 unsigned long addr
, unsigned long size
, pgprot_t prot
)
1183 unsigned long end
= addr
+ size
;
1184 struct mm_struct
*mm
= vma
->vm_mm
;
1187 BUG_ON(addr
>= end
);
1188 pgd
= pgd_offset(mm
, addr
);
1189 flush_cache_range(vma
, addr
, end
);
1191 next
= pgd_addr_end(addr
, end
);
1192 err
= zeromap_pud_range(mm
, pgd
, addr
, next
, prot
);
1195 } while (pgd
++, addr
= next
, addr
!= end
);
1199 pte_t
* fastcall
get_locked_pte(struct mm_struct
*mm
, unsigned long addr
, spinlock_t
**ptl
)
1201 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1202 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1204 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1206 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1212 * This is the old fallback for page remapping.
1214 * For historical reasons, it only allows reserved pages. Only
1215 * old drivers should use this, and they needed to mark their
1216 * pages reserved for the old functions anyway.
1218 static int insert_page(struct mm_struct
*mm
, unsigned long addr
, struct page
*page
, pgprot_t prot
)
1228 flush_dcache_page(page
);
1229 pte
= get_locked_pte(mm
, addr
, &ptl
);
1233 if (!pte_none(*pte
))
1236 /* Ok, finally just insert the thing.. */
1238 inc_mm_counter(mm
, file_rss
);
1239 page_add_file_rmap(page
);
1240 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1244 pte_unmap_unlock(pte
, ptl
);
1250 * vm_insert_page - insert single page into user vma
1251 * @vma: user vma to map to
1252 * @addr: target user address of this page
1253 * @page: source kernel page
1255 * This allows drivers to insert individual pages they've allocated
1258 * The page has to be a nice clean _individual_ kernel allocation.
1259 * If you allocate a compound page, you need to have marked it as
1260 * such (__GFP_COMP), or manually just split the page up yourself
1261 * (see split_page()).
1263 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1264 * took an arbitrary page protection parameter. This doesn't allow
1265 * that. Your vma protection will have to be set up correctly, which
1266 * means that if you want a shared writable mapping, you'd better
1267 * ask for a shared writable mapping!
1269 * The page does not need to be reserved.
1271 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
, struct page
*page
)
1273 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1275 if (!page_count(page
))
1277 vma
->vm_flags
|= VM_INSERTPAGE
;
1278 return insert_page(vma
->vm_mm
, addr
, page
, vma
->vm_page_prot
);
1280 EXPORT_SYMBOL(vm_insert_page
);
1283 * vm_insert_pfn - insert single pfn into user vma
1284 * @vma: user vma to map to
1285 * @addr: target user address of this page
1286 * @pfn: source kernel pfn
1288 * Similar to vm_inert_page, this allows drivers to insert individual pages
1289 * they've allocated into a user vma. Same comments apply.
1291 * This function should only be called from a vm_ops->fault handler, and
1292 * in that case the handler should return NULL.
1294 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1297 struct mm_struct
*mm
= vma
->vm_mm
;
1302 BUG_ON(!(vma
->vm_flags
& VM_PFNMAP
));
1303 BUG_ON(is_cow_mapping(vma
->vm_flags
));
1306 pte
= get_locked_pte(mm
, addr
, &ptl
);
1310 if (!pte_none(*pte
))
1313 /* Ok, finally just insert the thing.. */
1314 entry
= pfn_pte(pfn
, vma
->vm_page_prot
);
1315 set_pte_at(mm
, addr
, pte
, entry
);
1316 update_mmu_cache(vma
, addr
, entry
);
1320 pte_unmap_unlock(pte
, ptl
);
1325 EXPORT_SYMBOL(vm_insert_pfn
);
1328 * maps a range of physical memory into the requested pages. the old
1329 * mappings are removed. any references to nonexistent pages results
1330 * in null mappings (currently treated as "copy-on-access")
1332 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1333 unsigned long addr
, unsigned long end
,
1334 unsigned long pfn
, pgprot_t prot
)
1339 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1342 arch_enter_lazy_mmu_mode();
1344 BUG_ON(!pte_none(*pte
));
1345 set_pte_at(mm
, addr
, pte
, pfn_pte(pfn
, prot
));
1347 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1348 arch_leave_lazy_mmu_mode();
1349 pte_unmap_unlock(pte
- 1, ptl
);
1353 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1354 unsigned long addr
, unsigned long end
,
1355 unsigned long pfn
, pgprot_t prot
)
1360 pfn
-= addr
>> PAGE_SHIFT
;
1361 pmd
= pmd_alloc(mm
, pud
, addr
);
1365 next
= pmd_addr_end(addr
, end
);
1366 if (remap_pte_range(mm
, pmd
, addr
, next
,
1367 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1369 } while (pmd
++, addr
= next
, addr
!= end
);
1373 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1374 unsigned long addr
, unsigned long end
,
1375 unsigned long pfn
, pgprot_t prot
)
1380 pfn
-= addr
>> PAGE_SHIFT
;
1381 pud
= pud_alloc(mm
, pgd
, addr
);
1385 next
= pud_addr_end(addr
, end
);
1386 if (remap_pmd_range(mm
, pud
, addr
, next
,
1387 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1389 } while (pud
++, addr
= next
, addr
!= end
);
1394 * remap_pfn_range - remap kernel memory to userspace
1395 * @vma: user vma to map to
1396 * @addr: target user address to start at
1397 * @pfn: physical address of kernel memory
1398 * @size: size of map area
1399 * @prot: page protection flags for this mapping
1401 * Note: this is only safe if the mm semaphore is held when called.
1403 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1404 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1408 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1409 struct mm_struct
*mm
= vma
->vm_mm
;
1413 * Physically remapped pages are special. Tell the
1414 * rest of the world about it:
1415 * VM_IO tells people not to look at these pages
1416 * (accesses can have side effects).
1417 * VM_RESERVED is specified all over the place, because
1418 * in 2.4 it kept swapout's vma scan off this vma; but
1419 * in 2.6 the LRU scan won't even find its pages, so this
1420 * flag means no more than count its pages in reserved_vm,
1421 * and omit it from core dump, even when VM_IO turned off.
1422 * VM_PFNMAP tells the core MM that the base pages are just
1423 * raw PFN mappings, and do not have a "struct page" associated
1426 * There's a horrible special case to handle copy-on-write
1427 * behaviour that some programs depend on. We mark the "original"
1428 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1430 if (is_cow_mapping(vma
->vm_flags
)) {
1431 if (addr
!= vma
->vm_start
|| end
!= vma
->vm_end
)
1433 vma
->vm_pgoff
= pfn
;
1436 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1438 BUG_ON(addr
>= end
);
1439 pfn
-= addr
>> PAGE_SHIFT
;
1440 pgd
= pgd_offset(mm
, addr
);
1441 flush_cache_range(vma
, addr
, end
);
1443 next
= pgd_addr_end(addr
, end
);
1444 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1445 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1448 } while (pgd
++, addr
= next
, addr
!= end
);
1451 EXPORT_SYMBOL(remap_pfn_range
);
1453 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1454 unsigned long addr
, unsigned long end
,
1455 pte_fn_t fn
, void *data
)
1459 struct page
*pmd_page
;
1460 spinlock_t
*uninitialized_var(ptl
);
1462 pte
= (mm
== &init_mm
) ?
1463 pte_alloc_kernel(pmd
, addr
) :
1464 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1468 BUG_ON(pmd_huge(*pmd
));
1470 pmd_page
= pmd_page(*pmd
);
1473 err
= fn(pte
, pmd_page
, addr
, data
);
1476 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1479 pte_unmap_unlock(pte
-1, ptl
);
1483 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1484 unsigned long addr
, unsigned long end
,
1485 pte_fn_t fn
, void *data
)
1491 pmd
= pmd_alloc(mm
, pud
, addr
);
1495 next
= pmd_addr_end(addr
, end
);
1496 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1499 } while (pmd
++, addr
= next
, addr
!= end
);
1503 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1504 unsigned long addr
, unsigned long end
,
1505 pte_fn_t fn
, void *data
)
1511 pud
= pud_alloc(mm
, pgd
, addr
);
1515 next
= pud_addr_end(addr
, end
);
1516 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1519 } while (pud
++, addr
= next
, addr
!= end
);
1524 * Scan a region of virtual memory, filling in page tables as necessary
1525 * and calling a provided function on each leaf page table.
1527 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1528 unsigned long size
, pte_fn_t fn
, void *data
)
1532 unsigned long end
= addr
+ size
;
1535 BUG_ON(addr
>= end
);
1536 pgd
= pgd_offset(mm
, addr
);
1538 next
= pgd_addr_end(addr
, end
);
1539 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1542 } while (pgd
++, addr
= next
, addr
!= end
);
1545 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1548 * handle_pte_fault chooses page fault handler according to an entry
1549 * which was read non-atomically. Before making any commitment, on
1550 * those architectures or configurations (e.g. i386 with PAE) which
1551 * might give a mix of unmatched parts, do_swap_page and do_file_page
1552 * must check under lock before unmapping the pte and proceeding
1553 * (but do_wp_page is only called after already making such a check;
1554 * and do_anonymous_page and do_no_page can safely check later on).
1556 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1557 pte_t
*page_table
, pte_t orig_pte
)
1560 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1561 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1562 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1564 same
= pte_same(*page_table
, orig_pte
);
1568 pte_unmap(page_table
);
1573 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1574 * servicing faults for write access. In the normal case, do always want
1575 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1576 * that do not have writing enabled, when used by access_process_vm.
1578 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1580 if (likely(vma
->vm_flags
& VM_WRITE
))
1581 pte
= pte_mkwrite(pte
);
1585 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1588 * If the source page was a PFN mapping, we don't have
1589 * a "struct page" for it. We do a best-effort copy by
1590 * just copying from the original user address. If that
1591 * fails, we just zero-fill it. Live with it.
1593 if (unlikely(!src
)) {
1594 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1595 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1598 * This really shouldn't fail, because the page is there
1599 * in the page tables. But it might just be unreadable,
1600 * in which case we just give up and fill the result with
1603 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1604 memset(kaddr
, 0, PAGE_SIZE
);
1605 kunmap_atomic(kaddr
, KM_USER0
);
1606 flush_dcache_page(dst
);
1610 copy_user_highpage(dst
, src
, va
, vma
);
1614 * This routine handles present pages, when users try to write
1615 * to a shared page. It is done by copying the page to a new address
1616 * and decrementing the shared-page counter for the old page.
1618 * Note that this routine assumes that the protection checks have been
1619 * done by the caller (the low-level page fault routine in most cases).
1620 * Thus we can safely just mark it writable once we've done any necessary
1623 * We also mark the page dirty at this point even though the page will
1624 * change only once the write actually happens. This avoids a few races,
1625 * and potentially makes it more efficient.
1627 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1628 * but allow concurrent faults), with pte both mapped and locked.
1629 * We return with mmap_sem still held, but pte unmapped and unlocked.
1631 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1632 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1633 spinlock_t
*ptl
, pte_t orig_pte
)
1635 struct page
*old_page
, *new_page
;
1637 int reuse
= 0, ret
= VM_FAULT_MINOR
;
1638 struct page
*dirty_page
= NULL
;
1640 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1645 * Take out anonymous pages first, anonymous shared vmas are
1646 * not dirty accountable.
1648 if (PageAnon(old_page
)) {
1649 if (!TestSetPageLocked(old_page
)) {
1650 reuse
= can_share_swap_page(old_page
);
1651 unlock_page(old_page
);
1653 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1654 (VM_WRITE
|VM_SHARED
))) {
1656 * Only catch write-faults on shared writable pages,
1657 * read-only shared pages can get COWed by
1658 * get_user_pages(.write=1, .force=1).
1660 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
1662 * Notify the address space that the page is about to
1663 * become writable so that it can prohibit this or wait
1664 * for the page to get into an appropriate state.
1666 * We do this without the lock held, so that it can
1667 * sleep if it needs to.
1669 page_cache_get(old_page
);
1670 pte_unmap_unlock(page_table
, ptl
);
1672 if (vma
->vm_ops
->page_mkwrite(vma
, old_page
) < 0)
1673 goto unwritable_page
;
1676 * Since we dropped the lock we need to revalidate
1677 * the PTE as someone else may have changed it. If
1678 * they did, we just return, as we can count on the
1679 * MMU to tell us if they didn't also make it writable.
1681 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1683 page_cache_release(old_page
);
1684 if (!pte_same(*page_table
, orig_pte
))
1687 dirty_page
= old_page
;
1688 get_page(dirty_page
);
1693 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1694 entry
= pte_mkyoung(orig_pte
);
1695 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1696 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1)) {
1697 update_mmu_cache(vma
, address
, entry
);
1698 lazy_mmu_prot_update(entry
);
1700 ret
|= VM_FAULT_WRITE
;
1705 * Ok, we need to copy. Oh, well..
1707 page_cache_get(old_page
);
1709 pte_unmap_unlock(page_table
, ptl
);
1711 if (unlikely(anon_vma_prepare(vma
)))
1713 if (old_page
== ZERO_PAGE(address
)) {
1714 new_page
= alloc_zeroed_user_highpage(vma
, address
);
1718 new_page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
1721 cow_user_page(new_page
, old_page
, address
, vma
);
1725 * Re-check the pte - we dropped the lock
1727 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1728 if (likely(pte_same(*page_table
, orig_pte
))) {
1730 page_remove_rmap(old_page
, vma
);
1731 if (!PageAnon(old_page
)) {
1732 dec_mm_counter(mm
, file_rss
);
1733 inc_mm_counter(mm
, anon_rss
);
1736 inc_mm_counter(mm
, anon_rss
);
1737 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1738 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
1739 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1740 lazy_mmu_prot_update(entry
);
1742 * Clear the pte entry and flush it first, before updating the
1743 * pte with the new entry. This will avoid a race condition
1744 * seen in the presence of one thread doing SMC and another
1747 ptep_clear_flush(vma
, address
, page_table
);
1748 set_pte_at(mm
, address
, page_table
, entry
);
1749 update_mmu_cache(vma
, address
, entry
);
1750 lru_cache_add_active(new_page
);
1751 page_add_new_anon_rmap(new_page
, vma
, address
);
1753 /* Free the old page.. */
1754 new_page
= old_page
;
1755 ret
|= VM_FAULT_WRITE
;
1758 page_cache_release(new_page
);
1760 page_cache_release(old_page
);
1762 pte_unmap_unlock(page_table
, ptl
);
1764 set_page_dirty_balance(dirty_page
);
1765 put_page(dirty_page
);
1770 page_cache_release(old_page
);
1771 return VM_FAULT_OOM
;
1774 page_cache_release(old_page
);
1775 return VM_FAULT_SIGBUS
;
1779 * Helper functions for unmap_mapping_range().
1781 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1783 * We have to restart searching the prio_tree whenever we drop the lock,
1784 * since the iterator is only valid while the lock is held, and anyway
1785 * a later vma might be split and reinserted earlier while lock dropped.
1787 * The list of nonlinear vmas could be handled more efficiently, using
1788 * a placeholder, but handle it in the same way until a need is shown.
1789 * It is important to search the prio_tree before nonlinear list: a vma
1790 * may become nonlinear and be shifted from prio_tree to nonlinear list
1791 * while the lock is dropped; but never shifted from list to prio_tree.
1793 * In order to make forward progress despite restarting the search,
1794 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1795 * quickly skip it next time around. Since the prio_tree search only
1796 * shows us those vmas affected by unmapping the range in question, we
1797 * can't efficiently keep all vmas in step with mapping->truncate_count:
1798 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1799 * mapping->truncate_count and vma->vm_truncate_count are protected by
1802 * In order to make forward progress despite repeatedly restarting some
1803 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1804 * and restart from that address when we reach that vma again. It might
1805 * have been split or merged, shrunk or extended, but never shifted: so
1806 * restart_addr remains valid so long as it remains in the vma's range.
1807 * unmap_mapping_range forces truncate_count to leap over page-aligned
1808 * values so we can save vma's restart_addr in its truncate_count field.
1810 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1812 static void reset_vma_truncate_counts(struct address_space
*mapping
)
1814 struct vm_area_struct
*vma
;
1815 struct prio_tree_iter iter
;
1817 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
1818 vma
->vm_truncate_count
= 0;
1819 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
1820 vma
->vm_truncate_count
= 0;
1823 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
1824 unsigned long start_addr
, unsigned long end_addr
,
1825 struct zap_details
*details
)
1827 unsigned long restart_addr
;
1831 restart_addr
= vma
->vm_truncate_count
;
1832 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
1833 start_addr
= restart_addr
;
1834 if (start_addr
>= end_addr
) {
1835 /* Top of vma has been split off since last time */
1836 vma
->vm_truncate_count
= details
->truncate_count
;
1841 restart_addr
= zap_page_range(vma
, start_addr
,
1842 end_addr
- start_addr
, details
);
1843 need_break
= need_resched() ||
1844 need_lockbreak(details
->i_mmap_lock
);
1846 if (restart_addr
>= end_addr
) {
1847 /* We have now completed this vma: mark it so */
1848 vma
->vm_truncate_count
= details
->truncate_count
;
1852 /* Note restart_addr in vma's truncate_count field */
1853 vma
->vm_truncate_count
= restart_addr
;
1858 spin_unlock(details
->i_mmap_lock
);
1860 spin_lock(details
->i_mmap_lock
);
1864 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
1865 struct zap_details
*details
)
1867 struct vm_area_struct
*vma
;
1868 struct prio_tree_iter iter
;
1869 pgoff_t vba
, vea
, zba
, zea
;
1872 vma_prio_tree_foreach(vma
, &iter
, root
,
1873 details
->first_index
, details
->last_index
) {
1874 /* Skip quickly over those we have already dealt with */
1875 if (vma
->vm_truncate_count
== details
->truncate_count
)
1878 vba
= vma
->vm_pgoff
;
1879 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
1880 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1881 zba
= details
->first_index
;
1884 zea
= details
->last_index
;
1888 if (unmap_mapping_range_vma(vma
,
1889 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
1890 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
1896 static inline void unmap_mapping_range_list(struct list_head
*head
,
1897 struct zap_details
*details
)
1899 struct vm_area_struct
*vma
;
1902 * In nonlinear VMAs there is no correspondence between virtual address
1903 * offset and file offset. So we must perform an exhaustive search
1904 * across *all* the pages in each nonlinear VMA, not just the pages
1905 * whose virtual address lies outside the file truncation point.
1908 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
1909 /* Skip quickly over those we have already dealt with */
1910 if (vma
->vm_truncate_count
== details
->truncate_count
)
1912 details
->nonlinear_vma
= vma
;
1913 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
1914 vma
->vm_end
, details
) < 0)
1920 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
1921 * @mapping: the address space containing mmaps to be unmapped.
1922 * @holebegin: byte in first page to unmap, relative to the start of
1923 * the underlying file. This will be rounded down to a PAGE_SIZE
1924 * boundary. Note that this is different from vmtruncate(), which
1925 * must keep the partial page. In contrast, we must get rid of
1927 * @holelen: size of prospective hole in bytes. This will be rounded
1928 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1930 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1931 * but 0 when invalidating pagecache, don't throw away private data.
1933 void unmap_mapping_range(struct address_space
*mapping
,
1934 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
1936 struct zap_details details
;
1937 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
1938 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1940 /* Check for overflow. */
1941 if (sizeof(holelen
) > sizeof(hlen
)) {
1943 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1944 if (holeend
& ~(long long)ULONG_MAX
)
1945 hlen
= ULONG_MAX
- hba
+ 1;
1948 details
.check_mapping
= even_cows
? NULL
: mapping
;
1949 details
.nonlinear_vma
= NULL
;
1950 details
.first_index
= hba
;
1951 details
.last_index
= hba
+ hlen
- 1;
1952 if (details
.last_index
< details
.first_index
)
1953 details
.last_index
= ULONG_MAX
;
1954 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
1956 spin_lock(&mapping
->i_mmap_lock
);
1958 /* serialize i_size write against truncate_count write */
1960 /* Protect against page faults, and endless unmapping loops */
1961 mapping
->truncate_count
++;
1963 * For archs where spin_lock has inclusive semantics like ia64
1964 * this smp_mb() will prevent to read pagetable contents
1965 * before the truncate_count increment is visible to
1969 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
1970 if (mapping
->truncate_count
== 0)
1971 reset_vma_truncate_counts(mapping
);
1972 mapping
->truncate_count
++;
1974 details
.truncate_count
= mapping
->truncate_count
;
1976 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
1977 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
1978 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
1979 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
1980 spin_unlock(&mapping
->i_mmap_lock
);
1982 EXPORT_SYMBOL(unmap_mapping_range
);
1985 * vmtruncate - unmap mappings "freed" by truncate() syscall
1986 * @inode: inode of the file used
1987 * @offset: file offset to start truncating
1989 * NOTE! We have to be ready to update the memory sharing
1990 * between the file and the memory map for a potential last
1991 * incomplete page. Ugly, but necessary.
1993 int vmtruncate(struct inode
* inode
, loff_t offset
)
1995 struct address_space
*mapping
= inode
->i_mapping
;
1996 unsigned long limit
;
1998 if (inode
->i_size
< offset
)
2001 * truncation of in-use swapfiles is disallowed - it would cause
2002 * subsequent swapout to scribble on the now-freed blocks.
2004 if (IS_SWAPFILE(inode
))
2006 i_size_write(inode
, offset
);
2007 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2008 truncate_inode_pages(mapping
, offset
);
2012 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
2013 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
2015 if (offset
> inode
->i_sb
->s_maxbytes
)
2017 i_size_write(inode
, offset
);
2020 if (inode
->i_op
&& inode
->i_op
->truncate
)
2021 inode
->i_op
->truncate(inode
);
2024 send_sig(SIGXFSZ
, current
, 0);
2030 EXPORT_SYMBOL(vmtruncate
);
2032 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
2034 struct address_space
*mapping
= inode
->i_mapping
;
2037 * If the underlying filesystem is not going to provide
2038 * a way to truncate a range of blocks (punch a hole) -
2039 * we should return failure right now.
2041 if (!inode
->i_op
|| !inode
->i_op
->truncate_range
)
2044 mutex_lock(&inode
->i_mutex
);
2045 down_write(&inode
->i_alloc_sem
);
2046 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2047 truncate_inode_pages_range(mapping
, offset
, end
);
2048 inode
->i_op
->truncate_range(inode
, offset
, end
);
2049 up_write(&inode
->i_alloc_sem
);
2050 mutex_unlock(&inode
->i_mutex
);
2056 * swapin_readahead - swap in pages in hope we need them soon
2057 * @entry: swap entry of this memory
2058 * @addr: address to start
2059 * @vma: user vma this addresses belong to
2061 * Primitive swap readahead code. We simply read an aligned block of
2062 * (1 << page_cluster) entries in the swap area. This method is chosen
2063 * because it doesn't cost us any seek time. We also make sure to queue
2064 * the 'original' request together with the readahead ones...
2066 * This has been extended to use the NUMA policies from the mm triggering
2069 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
2071 void swapin_readahead(swp_entry_t entry
, unsigned long addr
,struct vm_area_struct
*vma
)
2074 struct vm_area_struct
*next_vma
= vma
? vma
->vm_next
: NULL
;
2077 struct page
*new_page
;
2078 unsigned long offset
;
2081 * Get the number of handles we should do readahead io to.
2083 num
= valid_swaphandles(entry
, &offset
);
2084 for (i
= 0; i
< num
; offset
++, i
++) {
2085 /* Ok, do the async read-ahead now */
2086 new_page
= read_swap_cache_async(swp_entry(swp_type(entry
),
2087 offset
), vma
, addr
);
2090 page_cache_release(new_page
);
2093 * Find the next applicable VMA for the NUMA policy.
2099 if (addr
>= vma
->vm_end
) {
2101 next_vma
= vma
? vma
->vm_next
: NULL
;
2103 if (vma
&& addr
< vma
->vm_start
)
2106 if (next_vma
&& addr
>= next_vma
->vm_start
) {
2108 next_vma
= vma
->vm_next
;
2113 lru_add_drain(); /* Push any new pages onto the LRU now */
2117 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2118 * but allow concurrent faults), and pte mapped but not yet locked.
2119 * We return with mmap_sem still held, but pte unmapped and unlocked.
2121 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2122 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2123 int write_access
, pte_t orig_pte
)
2129 int ret
= VM_FAULT_MINOR
;
2131 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2134 entry
= pte_to_swp_entry(orig_pte
);
2135 if (is_migration_entry(entry
)) {
2136 migration_entry_wait(mm
, pmd
, address
);
2139 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2140 page
= lookup_swap_cache(entry
);
2142 grab_swap_token(); /* Contend for token _before_ read-in */
2143 swapin_readahead(entry
, address
, vma
);
2144 page
= read_swap_cache_async(entry
, vma
, address
);
2147 * Back out if somebody else faulted in this pte
2148 * while we released the pte lock.
2150 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2151 if (likely(pte_same(*page_table
, orig_pte
)))
2153 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2157 /* Had to read the page from swap area: Major fault */
2158 ret
= VM_FAULT_MAJOR
;
2159 count_vm_event(PGMAJFAULT
);
2162 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2163 mark_page_accessed(page
);
2167 * Back out if somebody else already faulted in this pte.
2169 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2170 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2173 if (unlikely(!PageUptodate(page
))) {
2174 ret
= VM_FAULT_SIGBUS
;
2178 /* The page isn't present yet, go ahead with the fault. */
2180 inc_mm_counter(mm
, anon_rss
);
2181 pte
= mk_pte(page
, vma
->vm_page_prot
);
2182 if (write_access
&& can_share_swap_page(page
)) {
2183 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2187 flush_icache_page(vma
, page
);
2188 set_pte_at(mm
, address
, page_table
, pte
);
2189 page_add_anon_rmap(page
, vma
, address
);
2193 remove_exclusive_swap_page(page
);
2197 if (do_wp_page(mm
, vma
, address
,
2198 page_table
, pmd
, ptl
, pte
) == VM_FAULT_OOM
)
2203 /* No need to invalidate - it was non-present before */
2204 update_mmu_cache(vma
, address
, pte
);
2205 lazy_mmu_prot_update(pte
);
2207 pte_unmap_unlock(page_table
, ptl
);
2211 pte_unmap_unlock(page_table
, ptl
);
2213 page_cache_release(page
);
2218 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2219 * but allow concurrent faults), and pte mapped but not yet locked.
2220 * We return with mmap_sem still held, but pte unmapped and unlocked.
2222 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2223 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2231 /* Allocate our own private page. */
2232 pte_unmap(page_table
);
2234 if (unlikely(anon_vma_prepare(vma
)))
2236 page
= alloc_zeroed_user_highpage(vma
, address
);
2240 entry
= mk_pte(page
, vma
->vm_page_prot
);
2241 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2243 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2244 if (!pte_none(*page_table
))
2246 inc_mm_counter(mm
, anon_rss
);
2247 lru_cache_add_active(page
);
2248 page_add_new_anon_rmap(page
, vma
, address
);
2250 /* Map the ZERO_PAGE - vm_page_prot is readonly */
2251 page
= ZERO_PAGE(address
);
2252 page_cache_get(page
);
2253 entry
= mk_pte(page
, vma
->vm_page_prot
);
2255 ptl
= pte_lockptr(mm
, pmd
);
2257 if (!pte_none(*page_table
))
2259 inc_mm_counter(mm
, file_rss
);
2260 page_add_file_rmap(page
);
2263 set_pte_at(mm
, address
, page_table
, entry
);
2265 /* No need to invalidate - it was non-present before */
2266 update_mmu_cache(vma
, address
, entry
);
2267 lazy_mmu_prot_update(entry
);
2269 pte_unmap_unlock(page_table
, ptl
);
2270 return VM_FAULT_MINOR
;
2272 page_cache_release(page
);
2275 return VM_FAULT_OOM
;
2279 * do_no_page() tries to create a new page mapping. It aggressively
2280 * tries to share with existing pages, but makes a separate copy if
2281 * the "write_access" parameter is true in order to avoid the next
2284 * As this is called only for pages that do not currently exist, we
2285 * do not need to flush old virtual caches or the TLB.
2287 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2288 * but allow concurrent faults), and pte mapped but not yet locked.
2289 * We return with mmap_sem still held, but pte unmapped and unlocked.
2291 static int do_no_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2292 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2296 struct page
*new_page
;
2297 struct address_space
*mapping
= NULL
;
2299 unsigned int sequence
= 0;
2300 int ret
= VM_FAULT_MINOR
;
2302 struct page
*dirty_page
= NULL
;
2304 pte_unmap(page_table
);
2305 BUG_ON(vma
->vm_flags
& VM_PFNMAP
);
2308 mapping
= vma
->vm_file
->f_mapping
;
2309 sequence
= mapping
->truncate_count
;
2310 smp_rmb(); /* serializes i_size against truncate_count */
2313 new_page
= vma
->vm_ops
->nopage(vma
, address
& PAGE_MASK
, &ret
);
2315 * No smp_rmb is needed here as long as there's a full
2316 * spin_lock/unlock sequence inside the ->nopage callback
2317 * (for the pagecache lookup) that acts as an implicit
2318 * smp_mb() and prevents the i_size read to happen
2319 * after the next truncate_count read.
2322 /* no page was available -- either SIGBUS, OOM or REFAULT */
2323 if (unlikely(new_page
== NOPAGE_SIGBUS
))
2324 return VM_FAULT_SIGBUS
;
2325 else if (unlikely(new_page
== NOPAGE_OOM
))
2326 return VM_FAULT_OOM
;
2327 else if (unlikely(new_page
== NOPAGE_REFAULT
))
2328 return VM_FAULT_MINOR
;
2331 * Should we do an early C-O-W break?
2334 if (!(vma
->vm_flags
& VM_SHARED
)) {
2337 if (unlikely(anon_vma_prepare(vma
)))
2339 page
= alloc_page_vma(GFP_HIGHUSER
, vma
, address
);
2342 copy_user_highpage(page
, new_page
, address
, vma
);
2343 page_cache_release(new_page
);
2348 /* if the page will be shareable, see if the backing
2349 * address space wants to know that the page is about
2350 * to become writable */
2351 if (vma
->vm_ops
->page_mkwrite
&&
2352 vma
->vm_ops
->page_mkwrite(vma
, new_page
) < 0
2354 page_cache_release(new_page
);
2355 return VM_FAULT_SIGBUS
;
2360 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2362 * For a file-backed vma, someone could have truncated or otherwise
2363 * invalidated this page. If unmap_mapping_range got called,
2364 * retry getting the page.
2366 if (mapping
&& unlikely(sequence
!= mapping
->truncate_count
)) {
2367 pte_unmap_unlock(page_table
, ptl
);
2368 page_cache_release(new_page
);
2370 sequence
= mapping
->truncate_count
;
2376 * This silly early PAGE_DIRTY setting removes a race
2377 * due to the bad i386 page protection. But it's valid
2378 * for other architectures too.
2380 * Note that if write_access is true, we either now have
2381 * an exclusive copy of the page, or this is a shared mapping,
2382 * so we can make it writable and dirty to avoid having to
2383 * handle that later.
2385 /* Only go through if we didn't race with anybody else... */
2386 if (pte_none(*page_table
)) {
2387 flush_icache_page(vma
, new_page
);
2388 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2390 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2391 set_pte_at(mm
, address
, page_table
, entry
);
2393 inc_mm_counter(mm
, anon_rss
);
2394 lru_cache_add_active(new_page
);
2395 page_add_new_anon_rmap(new_page
, vma
, address
);
2397 inc_mm_counter(mm
, file_rss
);
2398 page_add_file_rmap(new_page
);
2400 dirty_page
= new_page
;
2401 get_page(dirty_page
);
2405 /* One of our sibling threads was faster, back out. */
2406 page_cache_release(new_page
);
2410 /* no need to invalidate: a not-present page shouldn't be cached */
2411 update_mmu_cache(vma
, address
, entry
);
2412 lazy_mmu_prot_update(entry
);
2414 pte_unmap_unlock(page_table
, ptl
);
2416 set_page_dirty_balance(dirty_page
);
2417 put_page(dirty_page
);
2421 page_cache_release(new_page
);
2422 return VM_FAULT_OOM
;
2426 * do_no_pfn() tries to create a new page mapping for a page without
2427 * a struct_page backing it
2429 * As this is called only for pages that do not currently exist, we
2430 * do not need to flush old virtual caches or the TLB.
2432 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2433 * but allow concurrent faults), and pte mapped but not yet locked.
2434 * We return with mmap_sem still held, but pte unmapped and unlocked.
2436 * It is expected that the ->nopfn handler always returns the same pfn
2437 * for a given virtual mapping.
2439 * Mark this `noinline' to prevent it from bloating the main pagefault code.
2441 static noinline
int do_no_pfn(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2442 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2448 int ret
= VM_FAULT_MINOR
;
2450 pte_unmap(page_table
);
2451 BUG_ON(!(vma
->vm_flags
& VM_PFNMAP
));
2452 BUG_ON(is_cow_mapping(vma
->vm_flags
));
2454 pfn
= vma
->vm_ops
->nopfn(vma
, address
& PAGE_MASK
);
2455 if (unlikely(pfn
== NOPFN_OOM
))
2456 return VM_FAULT_OOM
;
2457 else if (unlikely(pfn
== NOPFN_SIGBUS
))
2458 return VM_FAULT_SIGBUS
;
2459 else if (unlikely(pfn
== NOPFN_REFAULT
))
2460 return VM_FAULT_MINOR
;
2462 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2464 /* Only go through if we didn't race with anybody else... */
2465 if (pte_none(*page_table
)) {
2466 entry
= pfn_pte(pfn
, vma
->vm_page_prot
);
2468 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2469 set_pte_at(mm
, address
, page_table
, entry
);
2471 pte_unmap_unlock(page_table
, ptl
);
2476 * Fault of a previously existing named mapping. Repopulate the pte
2477 * from the encoded file_pte if possible. This enables swappable
2480 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2481 * but allow concurrent faults), and pte mapped but not yet locked.
2482 * We return with mmap_sem still held, but pte unmapped and unlocked.
2484 static int do_file_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2485 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2486 int write_access
, pte_t orig_pte
)
2491 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2492 return VM_FAULT_MINOR
;
2494 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
2496 * Page table corrupted: show pte and kill process.
2498 print_bad_pte(vma
, orig_pte
, address
);
2499 return VM_FAULT_OOM
;
2501 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2503 pgoff
= pte_to_pgoff(orig_pte
);
2504 err
= vma
->vm_ops
->populate(vma
, address
& PAGE_MASK
, PAGE_SIZE
,
2505 vma
->vm_page_prot
, pgoff
, 0);
2507 return VM_FAULT_OOM
;
2509 return VM_FAULT_SIGBUS
;
2510 return VM_FAULT_MAJOR
;
2514 * These routines also need to handle stuff like marking pages dirty
2515 * and/or accessed for architectures that don't do it in hardware (most
2516 * RISC architectures). The early dirtying is also good on the i386.
2518 * There is also a hook called "update_mmu_cache()" that architectures
2519 * with external mmu caches can use to update those (ie the Sparc or
2520 * PowerPC hashed page tables that act as extended TLBs).
2522 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2523 * but allow concurrent faults), and pte mapped but not yet locked.
2524 * We return with mmap_sem still held, but pte unmapped and unlocked.
2526 static inline int handle_pte_fault(struct mm_struct
*mm
,
2527 struct vm_area_struct
*vma
, unsigned long address
,
2528 pte_t
*pte
, pmd_t
*pmd
, int write_access
)
2534 if (!pte_present(entry
)) {
2535 if (pte_none(entry
)) {
2537 if (vma
->vm_ops
->nopage
)
2538 return do_no_page(mm
, vma
, address
,
2541 if (unlikely(vma
->vm_ops
->nopfn
))
2542 return do_no_pfn(mm
, vma
, address
, pte
,
2545 return do_anonymous_page(mm
, vma
, address
,
2546 pte
, pmd
, write_access
);
2548 if (pte_file(entry
))
2549 return do_file_page(mm
, vma
, address
,
2550 pte
, pmd
, write_access
, entry
);
2551 return do_swap_page(mm
, vma
, address
,
2552 pte
, pmd
, write_access
, entry
);
2555 ptl
= pte_lockptr(mm
, pmd
);
2557 if (unlikely(!pte_same(*pte
, entry
)))
2560 if (!pte_write(entry
))
2561 return do_wp_page(mm
, vma
, address
,
2562 pte
, pmd
, ptl
, entry
);
2563 entry
= pte_mkdirty(entry
);
2565 entry
= pte_mkyoung(entry
);
2566 if (ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
)) {
2567 update_mmu_cache(vma
, address
, entry
);
2568 lazy_mmu_prot_update(entry
);
2571 * This is needed only for protection faults but the arch code
2572 * is not yet telling us if this is a protection fault or not.
2573 * This still avoids useless tlb flushes for .text page faults
2577 flush_tlb_page(vma
, address
);
2580 pte_unmap_unlock(pte
, ptl
);
2581 return VM_FAULT_MINOR
;
2585 * By the time we get here, we already hold the mm semaphore
2587 int __handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2588 unsigned long address
, int write_access
)
2595 __set_current_state(TASK_RUNNING
);
2597 count_vm_event(PGFAULT
);
2599 if (unlikely(is_vm_hugetlb_page(vma
)))
2600 return hugetlb_fault(mm
, vma
, address
, write_access
);
2602 pgd
= pgd_offset(mm
, address
);
2603 pud
= pud_alloc(mm
, pgd
, address
);
2605 return VM_FAULT_OOM
;
2606 pmd
= pmd_alloc(mm
, pud
, address
);
2608 return VM_FAULT_OOM
;
2609 pte
= pte_alloc_map(mm
, pmd
, address
);
2611 return VM_FAULT_OOM
;
2613 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, write_access
);
2616 EXPORT_SYMBOL_GPL(__handle_mm_fault
);
2618 #ifndef __PAGETABLE_PUD_FOLDED
2620 * Allocate page upper directory.
2621 * We've already handled the fast-path in-line.
2623 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2625 pud_t
*new = pud_alloc_one(mm
, address
);
2629 spin_lock(&mm
->page_table_lock
);
2630 if (pgd_present(*pgd
)) /* Another has populated it */
2633 pgd_populate(mm
, pgd
, new);
2634 spin_unlock(&mm
->page_table_lock
);
2637 #endif /* __PAGETABLE_PUD_FOLDED */
2639 #ifndef __PAGETABLE_PMD_FOLDED
2641 * Allocate page middle directory.
2642 * We've already handled the fast-path in-line.
2644 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2646 pmd_t
*new = pmd_alloc_one(mm
, address
);
2650 spin_lock(&mm
->page_table_lock
);
2651 #ifndef __ARCH_HAS_4LEVEL_HACK
2652 if (pud_present(*pud
)) /* Another has populated it */
2655 pud_populate(mm
, pud
, new);
2657 if (pgd_present(*pud
)) /* Another has populated it */
2660 pgd_populate(mm
, pud
, new);
2661 #endif /* __ARCH_HAS_4LEVEL_HACK */
2662 spin_unlock(&mm
->page_table_lock
);
2665 #endif /* __PAGETABLE_PMD_FOLDED */
2667 int make_pages_present(unsigned long addr
, unsigned long end
)
2669 int ret
, len
, write
;
2670 struct vm_area_struct
* vma
;
2672 vma
= find_vma(current
->mm
, addr
);
2675 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2676 BUG_ON(addr
>= end
);
2677 BUG_ON(end
> vma
->vm_end
);
2678 len
= (end
+PAGE_SIZE
-1)/PAGE_SIZE
-addr
/PAGE_SIZE
;
2679 ret
= get_user_pages(current
, current
->mm
, addr
,
2680 len
, write
, 0, NULL
, NULL
);
2683 return ret
== len
? 0 : -1;
2687 * Map a vmalloc()-space virtual address to the physical page.
2689 struct page
* vmalloc_to_page(void * vmalloc_addr
)
2691 unsigned long addr
= (unsigned long) vmalloc_addr
;
2692 struct page
*page
= NULL
;
2693 pgd_t
*pgd
= pgd_offset_k(addr
);
2698 if (!pgd_none(*pgd
)) {
2699 pud
= pud_offset(pgd
, addr
);
2700 if (!pud_none(*pud
)) {
2701 pmd
= pmd_offset(pud
, addr
);
2702 if (!pmd_none(*pmd
)) {
2703 ptep
= pte_offset_map(pmd
, addr
);
2705 if (pte_present(pte
))
2706 page
= pte_page(pte
);
2714 EXPORT_SYMBOL(vmalloc_to_page
);
2717 * Map a vmalloc()-space virtual address to the physical page frame number.
2719 unsigned long vmalloc_to_pfn(void * vmalloc_addr
)
2721 return page_to_pfn(vmalloc_to_page(vmalloc_addr
));
2724 EXPORT_SYMBOL(vmalloc_to_pfn
);
2726 #if !defined(__HAVE_ARCH_GATE_AREA)
2728 #if defined(AT_SYSINFO_EHDR)
2729 static struct vm_area_struct gate_vma
;
2731 static int __init
gate_vma_init(void)
2733 gate_vma
.vm_mm
= NULL
;
2734 gate_vma
.vm_start
= FIXADDR_USER_START
;
2735 gate_vma
.vm_end
= FIXADDR_USER_END
;
2736 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
2737 gate_vma
.vm_page_prot
= __P101
;
2739 * Make sure the vDSO gets into every core dump.
2740 * Dumping its contents makes post-mortem fully interpretable later
2741 * without matching up the same kernel and hardware config to see
2742 * what PC values meant.
2744 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
2747 __initcall(gate_vma_init
);
2750 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2752 #ifdef AT_SYSINFO_EHDR
2759 int in_gate_area_no_task(unsigned long addr
)
2761 #ifdef AT_SYSINFO_EHDR
2762 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2768 #endif /* __HAVE_ARCH_GATE_AREA */
2771 * Access another process' address space.
2772 * Source/target buffer must be kernel space,
2773 * Do not walk the page table directly, use get_user_pages
2775 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
2777 struct mm_struct
*mm
;
2778 struct vm_area_struct
*vma
;
2780 void *old_buf
= buf
;
2782 mm
= get_task_mm(tsk
);
2786 down_read(&mm
->mmap_sem
);
2787 /* ignore errors, just check how much was sucessfully transfered */
2789 int bytes
, ret
, offset
;
2792 ret
= get_user_pages(tsk
, mm
, addr
, 1,
2793 write
, 1, &page
, &vma
);
2798 offset
= addr
& (PAGE_SIZE
-1);
2799 if (bytes
> PAGE_SIZE
-offset
)
2800 bytes
= PAGE_SIZE
-offset
;
2804 copy_to_user_page(vma
, page
, addr
,
2805 maddr
+ offset
, buf
, bytes
);
2806 set_page_dirty_lock(page
);
2808 copy_from_user_page(vma
, page
, addr
,
2809 buf
, maddr
+ offset
, bytes
);
2812 page_cache_release(page
);
2817 up_read(&mm
->mmap_sem
);
2820 return buf
- old_buf
;