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>
53 #include <linux/memcontrol.h>
54 #include <linux/mmu_notifier.h>
55 #include <linux/kallsyms.h>
56 #include <linux/swapops.h>
57 #include <linux/elf.h>
59 #include <asm/pgalloc.h>
60 #include <asm/uaccess.h>
62 #include <asm/tlbflush.h>
63 #include <asm/pgtable.h>
67 #ifndef CONFIG_NEED_MULTIPLE_NODES
68 /* use the per-pgdat data instead for discontigmem - mbligh */
69 unsigned long max_mapnr
;
72 EXPORT_SYMBOL(max_mapnr
);
73 EXPORT_SYMBOL(mem_map
);
76 unsigned long num_physpages
;
78 * A number of key systems in x86 including ioremap() rely on the assumption
79 * that high_memory defines the upper bound on direct map memory, then end
80 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
81 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
86 EXPORT_SYMBOL(num_physpages
);
87 EXPORT_SYMBOL(high_memory
);
90 * Randomize the address space (stacks, mmaps, brk, etc.).
92 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
93 * as ancient (libc5 based) binaries can segfault. )
95 int randomize_va_space __read_mostly
=
96 #ifdef CONFIG_COMPAT_BRK
102 static int __init
disable_randmaps(char *s
)
104 randomize_va_space
= 0;
107 __setup("norandmaps", disable_randmaps
);
111 * If a p?d_bad entry is found while walking page tables, report
112 * the error, before resetting entry to p?d_none. Usually (but
113 * very seldom) called out from the p?d_none_or_clear_bad macros.
116 void pgd_clear_bad(pgd_t
*pgd
)
122 void pud_clear_bad(pud_t
*pud
)
128 void pmd_clear_bad(pmd_t
*pmd
)
135 * Note: this doesn't free the actual pages themselves. That
136 * has been handled earlier when unmapping all the memory regions.
138 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
)
140 pgtable_t token
= pmd_pgtable(*pmd
);
142 pte_free_tlb(tlb
, token
);
146 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
147 unsigned long addr
, unsigned long end
,
148 unsigned long floor
, unsigned long ceiling
)
155 pmd
= pmd_offset(pud
, addr
);
157 next
= pmd_addr_end(addr
, end
);
158 if (pmd_none_or_clear_bad(pmd
))
160 free_pte_range(tlb
, pmd
);
161 } while (pmd
++, addr
= next
, addr
!= end
);
171 if (end
- 1 > ceiling
- 1)
174 pmd
= pmd_offset(pud
, start
);
176 pmd_free_tlb(tlb
, pmd
);
179 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
180 unsigned long addr
, unsigned long end
,
181 unsigned long floor
, unsigned long ceiling
)
188 pud
= pud_offset(pgd
, addr
);
190 next
= pud_addr_end(addr
, end
);
191 if (pud_none_or_clear_bad(pud
))
193 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
194 } while (pud
++, addr
= next
, addr
!= end
);
200 ceiling
&= PGDIR_MASK
;
204 if (end
- 1 > ceiling
- 1)
207 pud
= pud_offset(pgd
, start
);
209 pud_free_tlb(tlb
, pud
);
213 * This function frees user-level page tables of a process.
215 * Must be called with pagetable lock held.
217 void free_pgd_range(struct mmu_gather
*tlb
,
218 unsigned long addr
, unsigned long end
,
219 unsigned long floor
, unsigned long ceiling
)
226 * The next few lines have given us lots of grief...
228 * Why are we testing PMD* at this top level? Because often
229 * there will be no work to do at all, and we'd prefer not to
230 * go all the way down to the bottom just to discover that.
232 * Why all these "- 1"s? Because 0 represents both the bottom
233 * of the address space and the top of it (using -1 for the
234 * top wouldn't help much: the masks would do the wrong thing).
235 * The rule is that addr 0 and floor 0 refer to the bottom of
236 * the address space, but end 0 and ceiling 0 refer to the top
237 * Comparisons need to use "end - 1" and "ceiling - 1" (though
238 * that end 0 case should be mythical).
240 * Wherever addr is brought up or ceiling brought down, we must
241 * be careful to reject "the opposite 0" before it confuses the
242 * subsequent tests. But what about where end is brought down
243 * by PMD_SIZE below? no, end can't go down to 0 there.
245 * Whereas we round start (addr) and ceiling down, by different
246 * masks at different levels, in order to test whether a table
247 * now has no other vmas using it, so can be freed, we don't
248 * bother to round floor or end up - the tests don't need that.
262 if (end
- 1 > ceiling
- 1)
268 pgd
= pgd_offset(tlb
->mm
, addr
);
270 next
= pgd_addr_end(addr
, end
);
271 if (pgd_none_or_clear_bad(pgd
))
273 free_pud_range(tlb
, pgd
, addr
, next
, floor
, ceiling
);
274 } while (pgd
++, addr
= next
, addr
!= end
);
277 void free_pgtables(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
278 unsigned long floor
, unsigned long ceiling
)
281 struct vm_area_struct
*next
= vma
->vm_next
;
282 unsigned long addr
= vma
->vm_start
;
285 * Hide vma from rmap and vmtruncate before freeing pgtables
287 anon_vma_unlink(vma
);
288 unlink_file_vma(vma
);
290 if (is_vm_hugetlb_page(vma
)) {
291 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
292 floor
, next
? next
->vm_start
: ceiling
);
295 * Optimization: gather nearby vmas into one call down
297 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
298 && !is_vm_hugetlb_page(next
)) {
301 anon_vma_unlink(vma
);
302 unlink_file_vma(vma
);
304 free_pgd_range(tlb
, addr
, vma
->vm_end
,
305 floor
, next
? next
->vm_start
: ceiling
);
311 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
313 pgtable_t
new = pte_alloc_one(mm
, address
);
318 * Ensure all pte setup (eg. pte page lock and page clearing) are
319 * visible before the pte is made visible to other CPUs by being
320 * put into page tables.
322 * The other side of the story is the pointer chasing in the page
323 * table walking code (when walking the page table without locking;
324 * ie. most of the time). Fortunately, these data accesses consist
325 * of a chain of data-dependent loads, meaning most CPUs (alpha
326 * being the notable exception) will already guarantee loads are
327 * seen in-order. See the alpha page table accessors for the
328 * smp_read_barrier_depends() barriers in page table walking code.
330 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
332 spin_lock(&mm
->page_table_lock
);
333 if (!pmd_present(*pmd
)) { /* Has another populated it ? */
335 pmd_populate(mm
, pmd
, new);
338 spin_unlock(&mm
->page_table_lock
);
344 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
346 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
350 smp_wmb(); /* See comment in __pte_alloc */
352 spin_lock(&init_mm
.page_table_lock
);
353 if (!pmd_present(*pmd
)) { /* Has another populated it ? */
354 pmd_populate_kernel(&init_mm
, pmd
, new);
357 spin_unlock(&init_mm
.page_table_lock
);
359 pte_free_kernel(&init_mm
, new);
363 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
366 add_mm_counter(mm
, file_rss
, file_rss
);
368 add_mm_counter(mm
, anon_rss
, anon_rss
);
372 * This function is called to print an error when a bad pte
373 * is found. For example, we might have a PFN-mapped pte in
374 * a region that doesn't allow it.
376 * The calling function must still handle the error.
378 static void print_bad_pte(struct vm_area_struct
*vma
, unsigned long addr
,
379 pte_t pte
, struct page
*page
)
381 pgd_t
*pgd
= pgd_offset(vma
->vm_mm
, addr
);
382 pud_t
*pud
= pud_offset(pgd
, addr
);
383 pmd_t
*pmd
= pmd_offset(pud
, addr
);
384 struct address_space
*mapping
;
386 static unsigned long resume
;
387 static unsigned long nr_shown
;
388 static unsigned long nr_unshown
;
391 * Allow a burst of 60 reports, then keep quiet for that minute;
392 * or allow a steady drip of one report per second.
394 if (nr_shown
== 60) {
395 if (time_before(jiffies
, resume
)) {
401 "BUG: Bad page map: %lu messages suppressed\n",
408 resume
= jiffies
+ 60 * HZ
;
410 mapping
= vma
->vm_file
? vma
->vm_file
->f_mapping
: NULL
;
411 index
= linear_page_index(vma
, addr
);
414 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
416 (long long)pte_val(pte
), (long long)pmd_val(*pmd
));
419 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
420 page
, (void *)page
->flags
, page_count(page
),
421 page_mapcount(page
), page
->mapping
, page
->index
);
424 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
425 (void *)addr
, vma
->vm_flags
, vma
->anon_vma
, mapping
, index
);
427 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
430 print_symbol(KERN_ALERT
"vma->vm_ops->fault: %s\n",
431 (unsigned long)vma
->vm_ops
->fault
);
432 if (vma
->vm_file
&& vma
->vm_file
->f_op
)
433 print_symbol(KERN_ALERT
"vma->vm_file->f_op->mmap: %s\n",
434 (unsigned long)vma
->vm_file
->f_op
->mmap
);
436 add_taint(TAINT_BAD_PAGE
);
439 static inline int is_cow_mapping(unsigned int flags
)
441 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
445 * vm_normal_page -- This function gets the "struct page" associated with a pte.
447 * "Special" mappings do not wish to be associated with a "struct page" (either
448 * it doesn't exist, or it exists but they don't want to touch it). In this
449 * case, NULL is returned here. "Normal" mappings do have a struct page.
451 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
452 * pte bit, in which case this function is trivial. Secondly, an architecture
453 * may not have a spare pte bit, which requires a more complicated scheme,
456 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
457 * special mapping (even if there are underlying and valid "struct pages").
458 * COWed pages of a VM_PFNMAP are always normal.
460 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
461 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
462 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
463 * mapping will always honor the rule
465 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
467 * And for normal mappings this is false.
469 * This restricts such mappings to be a linear translation from virtual address
470 * to pfn. To get around this restriction, we allow arbitrary mappings so long
471 * as the vma is not a COW mapping; in that case, we know that all ptes are
472 * special (because none can have been COWed).
475 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
477 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
478 * page" backing, however the difference is that _all_ pages with a struct
479 * page (that is, those where pfn_valid is true) are refcounted and considered
480 * normal pages by the VM. The disadvantage is that pages are refcounted
481 * (which can be slower and simply not an option for some PFNMAP users). The
482 * advantage is that we don't have to follow the strict linearity rule of
483 * PFNMAP mappings in order to support COWable mappings.
486 #ifdef __HAVE_ARCH_PTE_SPECIAL
487 # define HAVE_PTE_SPECIAL 1
489 # define HAVE_PTE_SPECIAL 0
491 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
,
494 unsigned long pfn
= pte_pfn(pte
);
496 if (HAVE_PTE_SPECIAL
) {
497 if (likely(!pte_special(pte
)))
499 if (!(vma
->vm_flags
& (VM_PFNMAP
| VM_MIXEDMAP
)))
500 print_bad_pte(vma
, addr
, pte
, NULL
);
504 /* !HAVE_PTE_SPECIAL case follows: */
506 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
507 if (vma
->vm_flags
& VM_MIXEDMAP
) {
513 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
514 if (pfn
== vma
->vm_pgoff
+ off
)
516 if (!is_cow_mapping(vma
->vm_flags
))
522 if (unlikely(pfn
> highest_memmap_pfn
)) {
523 print_bad_pte(vma
, addr
, pte
, NULL
);
528 * NOTE! We still have PageReserved() pages in the page tables.
529 * eg. VDSO mappings can cause them to exist.
532 return pfn_to_page(pfn
);
536 * copy one vm_area from one task to the other. Assumes the page tables
537 * already present in the new task to be cleared in the whole range
538 * covered by this vma.
542 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
543 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
544 unsigned long addr
, int *rss
)
546 unsigned long vm_flags
= vma
->vm_flags
;
547 pte_t pte
= *src_pte
;
550 /* pte contains position in swap or file, so copy. */
551 if (unlikely(!pte_present(pte
))) {
552 if (!pte_file(pte
)) {
553 swp_entry_t entry
= pte_to_swp_entry(pte
);
555 swap_duplicate(entry
);
556 /* make sure dst_mm is on swapoff's mmlist. */
557 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
558 spin_lock(&mmlist_lock
);
559 if (list_empty(&dst_mm
->mmlist
))
560 list_add(&dst_mm
->mmlist
,
562 spin_unlock(&mmlist_lock
);
564 if (is_write_migration_entry(entry
) &&
565 is_cow_mapping(vm_flags
)) {
567 * COW mappings require pages in both parent
568 * and child to be set to read.
570 make_migration_entry_read(&entry
);
571 pte
= swp_entry_to_pte(entry
);
572 set_pte_at(src_mm
, addr
, src_pte
, pte
);
579 * If it's a COW mapping, write protect it both
580 * in the parent and the child
582 if (is_cow_mapping(vm_flags
)) {
583 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
584 pte
= pte_wrprotect(pte
);
588 * If it's a shared mapping, mark it clean in
591 if (vm_flags
& VM_SHARED
)
592 pte
= pte_mkclean(pte
);
593 pte
= pte_mkold(pte
);
595 page
= vm_normal_page(vma
, addr
, pte
);
598 page_dup_rmap(page
, vma
, addr
);
599 rss
[!!PageAnon(page
)]++;
603 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
606 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
607 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
608 unsigned long addr
, unsigned long end
)
610 pte_t
*src_pte
, *dst_pte
;
611 spinlock_t
*src_ptl
, *dst_ptl
;
617 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
620 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
621 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
622 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
623 arch_enter_lazy_mmu_mode();
627 * We are holding two locks at this point - either of them
628 * could generate latencies in another task on another CPU.
630 if (progress
>= 32) {
632 if (need_resched() ||
633 spin_needbreak(src_ptl
) || spin_needbreak(dst_ptl
))
636 if (pte_none(*src_pte
)) {
640 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
642 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
644 arch_leave_lazy_mmu_mode();
645 spin_unlock(src_ptl
);
646 pte_unmap_nested(src_pte
- 1);
647 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
648 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
655 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
656 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
657 unsigned long addr
, unsigned long end
)
659 pmd_t
*src_pmd
, *dst_pmd
;
662 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
665 src_pmd
= pmd_offset(src_pud
, addr
);
667 next
= pmd_addr_end(addr
, end
);
668 if (pmd_none_or_clear_bad(src_pmd
))
670 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
673 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
677 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
678 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
679 unsigned long addr
, unsigned long end
)
681 pud_t
*src_pud
, *dst_pud
;
684 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
687 src_pud
= pud_offset(src_pgd
, addr
);
689 next
= pud_addr_end(addr
, end
);
690 if (pud_none_or_clear_bad(src_pud
))
692 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
695 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
699 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
700 struct vm_area_struct
*vma
)
702 pgd_t
*src_pgd
, *dst_pgd
;
704 unsigned long addr
= vma
->vm_start
;
705 unsigned long end
= vma
->vm_end
;
709 * Don't copy ptes where a page fault will fill them correctly.
710 * Fork becomes much lighter when there are big shared or private
711 * readonly mappings. The tradeoff is that copy_page_range is more
712 * efficient than faulting.
714 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_PFNMAP
|VM_INSERTPAGE
))) {
719 if (is_vm_hugetlb_page(vma
))
720 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
722 if (unlikely(is_pfn_mapping(vma
))) {
724 * We do not free on error cases below as remove_vma
725 * gets called on error from higher level routine
727 ret
= track_pfn_vma_copy(vma
);
733 * We need to invalidate the secondary MMU mappings only when
734 * there could be a permission downgrade on the ptes of the
735 * parent mm. And a permission downgrade will only happen if
736 * is_cow_mapping() returns true.
738 if (is_cow_mapping(vma
->vm_flags
))
739 mmu_notifier_invalidate_range_start(src_mm
, addr
, end
);
742 dst_pgd
= pgd_offset(dst_mm
, addr
);
743 src_pgd
= pgd_offset(src_mm
, addr
);
745 next
= pgd_addr_end(addr
, end
);
746 if (pgd_none_or_clear_bad(src_pgd
))
748 if (unlikely(copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
753 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
755 if (is_cow_mapping(vma
->vm_flags
))
756 mmu_notifier_invalidate_range_end(src_mm
,
761 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
762 struct vm_area_struct
*vma
, pmd_t
*pmd
,
763 unsigned long addr
, unsigned long end
,
764 long *zap_work
, struct zap_details
*details
)
766 struct mm_struct
*mm
= tlb
->mm
;
772 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
773 arch_enter_lazy_mmu_mode();
776 if (pte_none(ptent
)) {
781 (*zap_work
) -= PAGE_SIZE
;
783 if (pte_present(ptent
)) {
786 page
= vm_normal_page(vma
, addr
, ptent
);
787 if (unlikely(details
) && page
) {
789 * unmap_shared_mapping_pages() wants to
790 * invalidate cache without truncating:
791 * unmap shared but keep private pages.
793 if (details
->check_mapping
&&
794 details
->check_mapping
!= page
->mapping
)
797 * Each page->index must be checked when
798 * invalidating or truncating nonlinear.
800 if (details
->nonlinear_vma
&&
801 (page
->index
< details
->first_index
||
802 page
->index
> details
->last_index
))
805 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
807 tlb_remove_tlb_entry(tlb
, pte
, addr
);
810 if (unlikely(details
) && details
->nonlinear_vma
811 && linear_page_index(details
->nonlinear_vma
,
812 addr
) != page
->index
)
813 set_pte_at(mm
, addr
, pte
,
814 pgoff_to_pte(page
->index
));
818 if (pte_dirty(ptent
))
819 set_page_dirty(page
);
820 if (pte_young(ptent
) &&
821 likely(!VM_SequentialReadHint(vma
)))
822 mark_page_accessed(page
);
825 page_remove_rmap(page
);
826 if (unlikely(page_mapcount(page
) < 0))
827 print_bad_pte(vma
, addr
, ptent
, page
);
828 tlb_remove_page(tlb
, page
);
832 * If details->check_mapping, we leave swap entries;
833 * if details->nonlinear_vma, we leave file entries.
835 if (unlikely(details
))
837 if (pte_file(ptent
)) {
838 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
)))
839 print_bad_pte(vma
, addr
, ptent
, NULL
);
841 (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent
))))
842 print_bad_pte(vma
, addr
, ptent
, NULL
);
843 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
844 } while (pte
++, addr
+= PAGE_SIZE
, (addr
!= end
&& *zap_work
> 0));
846 add_mm_rss(mm
, file_rss
, anon_rss
);
847 arch_leave_lazy_mmu_mode();
848 pte_unmap_unlock(pte
- 1, ptl
);
853 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
854 struct vm_area_struct
*vma
, pud_t
*pud
,
855 unsigned long addr
, unsigned long end
,
856 long *zap_work
, struct zap_details
*details
)
861 pmd
= pmd_offset(pud
, addr
);
863 next
= pmd_addr_end(addr
, end
);
864 if (pmd_none_or_clear_bad(pmd
)) {
868 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
,
870 } while (pmd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
875 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
876 struct vm_area_struct
*vma
, pgd_t
*pgd
,
877 unsigned long addr
, unsigned long end
,
878 long *zap_work
, struct zap_details
*details
)
883 pud
= pud_offset(pgd
, addr
);
885 next
= pud_addr_end(addr
, end
);
886 if (pud_none_or_clear_bad(pud
)) {
890 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
,
892 } while (pud
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
897 static unsigned long unmap_page_range(struct mmu_gather
*tlb
,
898 struct vm_area_struct
*vma
,
899 unsigned long addr
, unsigned long end
,
900 long *zap_work
, struct zap_details
*details
)
905 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
909 tlb_start_vma(tlb
, vma
);
910 pgd
= pgd_offset(vma
->vm_mm
, addr
);
912 next
= pgd_addr_end(addr
, end
);
913 if (pgd_none_or_clear_bad(pgd
)) {
917 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
,
919 } while (pgd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
920 tlb_end_vma(tlb
, vma
);
925 #ifdef CONFIG_PREEMPT
926 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
928 /* No preempt: go for improved straight-line efficiency */
929 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
933 * unmap_vmas - unmap a range of memory covered by a list of vma's
934 * @tlbp: address of the caller's struct mmu_gather
935 * @vma: the starting vma
936 * @start_addr: virtual address at which to start unmapping
937 * @end_addr: virtual address at which to end unmapping
938 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
939 * @details: details of nonlinear truncation or shared cache invalidation
941 * Returns the end address of the unmapping (restart addr if interrupted).
943 * Unmap all pages in the vma list.
945 * We aim to not hold locks for too long (for scheduling latency reasons).
946 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
947 * return the ending mmu_gather to the caller.
949 * Only addresses between `start' and `end' will be unmapped.
951 * The VMA list must be sorted in ascending virtual address order.
953 * unmap_vmas() assumes that the caller will flush the whole unmapped address
954 * range after unmap_vmas() returns. So the only responsibility here is to
955 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
956 * drops the lock and schedules.
958 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
959 struct vm_area_struct
*vma
, unsigned long start_addr
,
960 unsigned long end_addr
, unsigned long *nr_accounted
,
961 struct zap_details
*details
)
963 long zap_work
= ZAP_BLOCK_SIZE
;
964 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
965 int tlb_start_valid
= 0;
966 unsigned long start
= start_addr
;
967 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
968 int fullmm
= (*tlbp
)->fullmm
;
969 struct mm_struct
*mm
= vma
->vm_mm
;
971 mmu_notifier_invalidate_range_start(mm
, start_addr
, end_addr
);
972 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
975 start
= max(vma
->vm_start
, start_addr
);
976 if (start
>= vma
->vm_end
)
978 end
= min(vma
->vm_end
, end_addr
);
979 if (end
<= vma
->vm_start
)
982 if (vma
->vm_flags
& VM_ACCOUNT
)
983 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
985 if (unlikely(is_pfn_mapping(vma
)))
986 untrack_pfn_vma(vma
, 0, 0);
988 while (start
!= end
) {
989 if (!tlb_start_valid
) {
994 if (unlikely(is_vm_hugetlb_page(vma
))) {
996 * It is undesirable to test vma->vm_file as it
997 * should be non-null for valid hugetlb area.
998 * However, vm_file will be NULL in the error
999 * cleanup path of do_mmap_pgoff. When
1000 * hugetlbfs ->mmap method fails,
1001 * do_mmap_pgoff() nullifies vma->vm_file
1002 * before calling this function to clean up.
1003 * Since no pte has actually been setup, it is
1004 * safe to do nothing in this case.
1007 unmap_hugepage_range(vma
, start
, end
, NULL
);
1008 zap_work
-= (end
- start
) /
1009 pages_per_huge_page(hstate_vma(vma
));
1014 start
= unmap_page_range(*tlbp
, vma
,
1015 start
, end
, &zap_work
, details
);
1018 BUG_ON(start
!= end
);
1022 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
1024 if (need_resched() ||
1025 (i_mmap_lock
&& spin_needbreak(i_mmap_lock
))) {
1033 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
1034 tlb_start_valid
= 0;
1035 zap_work
= ZAP_BLOCK_SIZE
;
1039 mmu_notifier_invalidate_range_end(mm
, start_addr
, end_addr
);
1040 return start
; /* which is now the end (or restart) address */
1044 * zap_page_range - remove user pages in a given range
1045 * @vma: vm_area_struct holding the applicable pages
1046 * @address: starting address of pages to zap
1047 * @size: number of bytes to zap
1048 * @details: details of nonlinear truncation or shared cache invalidation
1050 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
1051 unsigned long size
, struct zap_details
*details
)
1053 struct mm_struct
*mm
= vma
->vm_mm
;
1054 struct mmu_gather
*tlb
;
1055 unsigned long end
= address
+ size
;
1056 unsigned long nr_accounted
= 0;
1059 tlb
= tlb_gather_mmu(mm
, 0);
1060 update_hiwater_rss(mm
);
1061 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
1063 tlb_finish_mmu(tlb
, address
, end
);
1068 * zap_vma_ptes - remove ptes mapping the vma
1069 * @vma: vm_area_struct holding ptes to be zapped
1070 * @address: starting address of pages to zap
1071 * @size: number of bytes to zap
1073 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1075 * The entire address range must be fully contained within the vma.
1077 * Returns 0 if successful.
1079 int zap_vma_ptes(struct vm_area_struct
*vma
, unsigned long address
,
1082 if (address
< vma
->vm_start
|| address
+ size
> vma
->vm_end
||
1083 !(vma
->vm_flags
& VM_PFNMAP
))
1085 zap_page_range(vma
, address
, size
, NULL
);
1088 EXPORT_SYMBOL_GPL(zap_vma_ptes
);
1091 * Do a quick page-table lookup for a single page.
1093 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
1102 struct mm_struct
*mm
= vma
->vm_mm
;
1104 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
1105 if (!IS_ERR(page
)) {
1106 BUG_ON(flags
& FOLL_GET
);
1111 pgd
= pgd_offset(mm
, address
);
1112 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
1115 pud
= pud_offset(pgd
, address
);
1118 if (pud_huge(*pud
)) {
1119 BUG_ON(flags
& FOLL_GET
);
1120 page
= follow_huge_pud(mm
, address
, pud
, flags
& FOLL_WRITE
);
1123 if (unlikely(pud_bad(*pud
)))
1126 pmd
= pmd_offset(pud
, address
);
1129 if (pmd_huge(*pmd
)) {
1130 BUG_ON(flags
& FOLL_GET
);
1131 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
1134 if (unlikely(pmd_bad(*pmd
)))
1137 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1140 if (!pte_present(pte
))
1142 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
1144 page
= vm_normal_page(vma
, address
, pte
);
1145 if (unlikely(!page
))
1148 if (flags
& FOLL_GET
)
1150 if (flags
& FOLL_TOUCH
) {
1151 if ((flags
& FOLL_WRITE
) &&
1152 !pte_dirty(pte
) && !PageDirty(page
))
1153 set_page_dirty(page
);
1155 * pte_mkyoung() would be more correct here, but atomic care
1156 * is needed to avoid losing the dirty bit: it is easier to use
1157 * mark_page_accessed().
1159 mark_page_accessed(page
);
1162 pte_unmap_unlock(ptep
, ptl
);
1167 pte_unmap_unlock(ptep
, ptl
);
1168 return ERR_PTR(-EFAULT
);
1171 pte_unmap_unlock(ptep
, ptl
);
1174 /* Fall through to ZERO_PAGE handling */
1177 * When core dumping an enormous anonymous area that nobody
1178 * has touched so far, we don't want to allocate page tables.
1180 if (flags
& FOLL_ANON
) {
1181 page
= ZERO_PAGE(0);
1182 if (flags
& FOLL_GET
)
1184 BUG_ON(flags
& FOLL_WRITE
);
1189 /* Can we do the FOLL_ANON optimization? */
1190 static inline int use_zero_page(struct vm_area_struct
*vma
)
1193 * We don't want to optimize FOLL_ANON for make_pages_present()
1194 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
1195 * we want to get the page from the page tables to make sure
1196 * that we serialize and update with any other user of that
1199 if (vma
->vm_flags
& (VM_LOCKED
| VM_SHARED
))
1202 * And if we have a fault routine, it's not an anonymous region.
1204 return !vma
->vm_ops
|| !vma
->vm_ops
->fault
;
1209 int __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1210 unsigned long start
, int len
, int flags
,
1211 struct page
**pages
, struct vm_area_struct
**vmas
)
1214 unsigned int vm_flags
= 0;
1215 int write
= !!(flags
& GUP_FLAGS_WRITE
);
1216 int force
= !!(flags
& GUP_FLAGS_FORCE
);
1217 int ignore
= !!(flags
& GUP_FLAGS_IGNORE_VMA_PERMISSIONS
);
1218 int ignore_sigkill
= !!(flags
& GUP_FLAGS_IGNORE_SIGKILL
);
1223 * Require read or write permissions.
1224 * If 'force' is set, we only require the "MAY" flags.
1226 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
1227 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
1231 struct vm_area_struct
*vma
;
1232 unsigned int foll_flags
;
1234 vma
= find_extend_vma(mm
, start
);
1235 if (!vma
&& in_gate_area(tsk
, start
)) {
1236 unsigned long pg
= start
& PAGE_MASK
;
1237 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1243 /* user gate pages are read-only */
1244 if (!ignore
&& write
)
1245 return i
? : -EFAULT
;
1247 pgd
= pgd_offset_k(pg
);
1249 pgd
= pgd_offset_gate(mm
, pg
);
1250 BUG_ON(pgd_none(*pgd
));
1251 pud
= pud_offset(pgd
, pg
);
1252 BUG_ON(pud_none(*pud
));
1253 pmd
= pmd_offset(pud
, pg
);
1255 return i
? : -EFAULT
;
1256 pte
= pte_offset_map(pmd
, pg
);
1257 if (pte_none(*pte
)) {
1259 return i
? : -EFAULT
;
1262 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1277 (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
1278 (!ignore
&& !(vm_flags
& vma
->vm_flags
)))
1279 return i
? : -EFAULT
;
1281 if (is_vm_hugetlb_page(vma
)) {
1282 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1283 &start
, &len
, i
, write
);
1287 foll_flags
= FOLL_TOUCH
;
1289 foll_flags
|= FOLL_GET
;
1290 if (!write
&& use_zero_page(vma
))
1291 foll_flags
|= FOLL_ANON
;
1297 * If we have a pending SIGKILL, don't keep faulting
1298 * pages and potentially allocating memory, unless
1299 * current is handling munlock--e.g., on exit. In
1300 * that case, we are not allocating memory. Rather,
1301 * we're only unlocking already resident/mapped pages.
1303 if (unlikely(!ignore_sigkill
&&
1304 fatal_signal_pending(current
)))
1305 return i
? i
: -ERESTARTSYS
;
1308 foll_flags
|= FOLL_WRITE
;
1311 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1313 ret
= handle_mm_fault(mm
, vma
, start
,
1314 foll_flags
& FOLL_WRITE
);
1315 if (ret
& VM_FAULT_ERROR
) {
1316 if (ret
& VM_FAULT_OOM
)
1317 return i
? i
: -ENOMEM
;
1318 else if (ret
& VM_FAULT_SIGBUS
)
1319 return i
? i
: -EFAULT
;
1322 if (ret
& VM_FAULT_MAJOR
)
1328 * The VM_FAULT_WRITE bit tells us that
1329 * do_wp_page has broken COW when necessary,
1330 * even if maybe_mkwrite decided not to set
1331 * pte_write. We can thus safely do subsequent
1332 * page lookups as if they were reads. But only
1333 * do so when looping for pte_write is futile:
1334 * in some cases userspace may also be wanting
1335 * to write to the gotten user page, which a
1336 * read fault here might prevent (a readonly
1337 * page might get reCOWed by userspace write).
1339 if ((ret
& VM_FAULT_WRITE
) &&
1340 !(vma
->vm_flags
& VM_WRITE
))
1341 foll_flags
&= ~FOLL_WRITE
;
1346 return i
? i
: PTR_ERR(page
);
1350 flush_anon_page(vma
, page
, start
);
1351 flush_dcache_page(page
);
1358 } while (len
&& start
< vma
->vm_end
);
1363 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1364 unsigned long start
, int len
, int write
, int force
,
1365 struct page
**pages
, struct vm_area_struct
**vmas
)
1370 flags
|= GUP_FLAGS_WRITE
;
1372 flags
|= GUP_FLAGS_FORCE
;
1374 return __get_user_pages(tsk
, mm
,
1379 EXPORT_SYMBOL(get_user_pages
);
1381 pte_t
*get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
1384 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1385 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1387 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1389 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1395 * This is the old fallback for page remapping.
1397 * For historical reasons, it only allows reserved pages. Only
1398 * old drivers should use this, and they needed to mark their
1399 * pages reserved for the old functions anyway.
1401 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1402 struct page
*page
, pgprot_t prot
)
1404 struct mm_struct
*mm
= vma
->vm_mm
;
1413 flush_dcache_page(page
);
1414 pte
= get_locked_pte(mm
, addr
, &ptl
);
1418 if (!pte_none(*pte
))
1421 /* Ok, finally just insert the thing.. */
1423 inc_mm_counter(mm
, file_rss
);
1424 page_add_file_rmap(page
);
1425 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1428 pte_unmap_unlock(pte
, ptl
);
1431 pte_unmap_unlock(pte
, ptl
);
1437 * vm_insert_page - insert single page into user vma
1438 * @vma: user vma to map to
1439 * @addr: target user address of this page
1440 * @page: source kernel page
1442 * This allows drivers to insert individual pages they've allocated
1445 * The page has to be a nice clean _individual_ kernel allocation.
1446 * If you allocate a compound page, you need to have marked it as
1447 * such (__GFP_COMP), or manually just split the page up yourself
1448 * (see split_page()).
1450 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1451 * took an arbitrary page protection parameter. This doesn't allow
1452 * that. Your vma protection will have to be set up correctly, which
1453 * means that if you want a shared writable mapping, you'd better
1454 * ask for a shared writable mapping!
1456 * The page does not need to be reserved.
1458 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1461 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1463 if (!page_count(page
))
1465 vma
->vm_flags
|= VM_INSERTPAGE
;
1466 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1468 EXPORT_SYMBOL(vm_insert_page
);
1470 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1471 unsigned long pfn
, pgprot_t prot
)
1473 struct mm_struct
*mm
= vma
->vm_mm
;
1479 pte
= get_locked_pte(mm
, addr
, &ptl
);
1483 if (!pte_none(*pte
))
1486 /* Ok, finally just insert the thing.. */
1487 entry
= pte_mkspecial(pfn_pte(pfn
, prot
));
1488 set_pte_at(mm
, addr
, pte
, entry
);
1489 update_mmu_cache(vma
, addr
, entry
); /* XXX: why not for insert_page? */
1493 pte_unmap_unlock(pte
, ptl
);
1499 * vm_insert_pfn - insert single pfn into user vma
1500 * @vma: user vma to map to
1501 * @addr: target user address of this page
1502 * @pfn: source kernel pfn
1504 * Similar to vm_inert_page, this allows drivers to insert individual pages
1505 * they've allocated into a user vma. Same comments apply.
1507 * This function should only be called from a vm_ops->fault handler, and
1508 * in that case the handler should return NULL.
1510 * vma cannot be a COW mapping.
1512 * As this is called only for pages that do not currently exist, we
1513 * do not need to flush old virtual caches or the TLB.
1515 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1519 pgprot_t pgprot
= vma
->vm_page_prot
;
1521 * Technically, architectures with pte_special can avoid all these
1522 * restrictions (same for remap_pfn_range). However we would like
1523 * consistency in testing and feature parity among all, so we should
1524 * try to keep these invariants in place for everybody.
1526 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
1527 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
1528 (VM_PFNMAP
|VM_MIXEDMAP
));
1529 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
1530 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
1532 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1534 if (track_pfn_vma_new(vma
, &pgprot
, pfn
, PAGE_SIZE
))
1537 ret
= insert_pfn(vma
, addr
, pfn
, pgprot
);
1540 untrack_pfn_vma(vma
, pfn
, PAGE_SIZE
);
1544 EXPORT_SYMBOL(vm_insert_pfn
);
1546 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1549 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
1551 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1555 * If we don't have pte special, then we have to use the pfn_valid()
1556 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1557 * refcount the page if pfn_valid is true (hence insert_page rather
1560 if (!HAVE_PTE_SPECIAL
&& pfn_valid(pfn
)) {
1563 page
= pfn_to_page(pfn
);
1564 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1566 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
1568 EXPORT_SYMBOL(vm_insert_mixed
);
1571 * maps a range of physical memory into the requested pages. the old
1572 * mappings are removed. any references to nonexistent pages results
1573 * in null mappings (currently treated as "copy-on-access")
1575 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1576 unsigned long addr
, unsigned long end
,
1577 unsigned long pfn
, pgprot_t prot
)
1582 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1585 arch_enter_lazy_mmu_mode();
1587 BUG_ON(!pte_none(*pte
));
1588 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
1590 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1591 arch_leave_lazy_mmu_mode();
1592 pte_unmap_unlock(pte
- 1, ptl
);
1596 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1597 unsigned long addr
, unsigned long end
,
1598 unsigned long pfn
, pgprot_t prot
)
1603 pfn
-= addr
>> PAGE_SHIFT
;
1604 pmd
= pmd_alloc(mm
, pud
, addr
);
1608 next
= pmd_addr_end(addr
, end
);
1609 if (remap_pte_range(mm
, pmd
, addr
, next
,
1610 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1612 } while (pmd
++, addr
= next
, addr
!= end
);
1616 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1617 unsigned long addr
, unsigned long end
,
1618 unsigned long pfn
, pgprot_t prot
)
1623 pfn
-= addr
>> PAGE_SHIFT
;
1624 pud
= pud_alloc(mm
, pgd
, addr
);
1628 next
= pud_addr_end(addr
, end
);
1629 if (remap_pmd_range(mm
, pud
, addr
, next
,
1630 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1632 } while (pud
++, addr
= next
, addr
!= end
);
1637 * remap_pfn_range - remap kernel memory to userspace
1638 * @vma: user vma to map to
1639 * @addr: target user address to start at
1640 * @pfn: physical address of kernel memory
1641 * @size: size of map area
1642 * @prot: page protection flags for this mapping
1644 * Note: this is only safe if the mm semaphore is held when called.
1646 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1647 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1651 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1652 struct mm_struct
*mm
= vma
->vm_mm
;
1656 * Physically remapped pages are special. Tell the
1657 * rest of the world about it:
1658 * VM_IO tells people not to look at these pages
1659 * (accesses can have side effects).
1660 * VM_RESERVED is specified all over the place, because
1661 * in 2.4 it kept swapout's vma scan off this vma; but
1662 * in 2.6 the LRU scan won't even find its pages, so this
1663 * flag means no more than count its pages in reserved_vm,
1664 * and omit it from core dump, even when VM_IO turned off.
1665 * VM_PFNMAP tells the core MM that the base pages are just
1666 * raw PFN mappings, and do not have a "struct page" associated
1669 * There's a horrible special case to handle copy-on-write
1670 * behaviour that some programs depend on. We mark the "original"
1671 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1673 if (addr
== vma
->vm_start
&& end
== vma
->vm_end
) {
1674 vma
->vm_pgoff
= pfn
;
1675 vma
->vm_flags
|= VM_PFN_AT_MMAP
;
1676 } else if (is_cow_mapping(vma
->vm_flags
))
1679 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1681 err
= track_pfn_vma_new(vma
, &prot
, pfn
, PAGE_ALIGN(size
));
1684 * To indicate that track_pfn related cleanup is not
1685 * needed from higher level routine calling unmap_vmas
1687 vma
->vm_flags
&= ~(VM_IO
| VM_RESERVED
| VM_PFNMAP
);
1688 vma
->vm_flags
&= ~VM_PFN_AT_MMAP
;
1692 BUG_ON(addr
>= end
);
1693 pfn
-= addr
>> PAGE_SHIFT
;
1694 pgd
= pgd_offset(mm
, addr
);
1695 flush_cache_range(vma
, addr
, end
);
1697 next
= pgd_addr_end(addr
, end
);
1698 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1699 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1702 } while (pgd
++, addr
= next
, addr
!= end
);
1705 untrack_pfn_vma(vma
, pfn
, PAGE_ALIGN(size
));
1709 EXPORT_SYMBOL(remap_pfn_range
);
1711 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1712 unsigned long addr
, unsigned long end
,
1713 pte_fn_t fn
, void *data
)
1718 spinlock_t
*uninitialized_var(ptl
);
1720 pte
= (mm
== &init_mm
) ?
1721 pte_alloc_kernel(pmd
, addr
) :
1722 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1726 BUG_ON(pmd_huge(*pmd
));
1728 arch_enter_lazy_mmu_mode();
1730 token
= pmd_pgtable(*pmd
);
1733 err
= fn(pte
, token
, addr
, data
);
1736 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1738 arch_leave_lazy_mmu_mode();
1741 pte_unmap_unlock(pte
-1, ptl
);
1745 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1746 unsigned long addr
, unsigned long end
,
1747 pte_fn_t fn
, void *data
)
1753 BUG_ON(pud_huge(*pud
));
1755 pmd
= pmd_alloc(mm
, pud
, addr
);
1759 next
= pmd_addr_end(addr
, end
);
1760 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1763 } while (pmd
++, addr
= next
, addr
!= end
);
1767 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1768 unsigned long addr
, unsigned long end
,
1769 pte_fn_t fn
, void *data
)
1775 pud
= pud_alloc(mm
, pgd
, addr
);
1779 next
= pud_addr_end(addr
, end
);
1780 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1783 } while (pud
++, addr
= next
, addr
!= end
);
1788 * Scan a region of virtual memory, filling in page tables as necessary
1789 * and calling a provided function on each leaf page table.
1791 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1792 unsigned long size
, pte_fn_t fn
, void *data
)
1796 unsigned long start
= addr
, end
= addr
+ size
;
1799 BUG_ON(addr
>= end
);
1800 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1801 pgd
= pgd_offset(mm
, addr
);
1803 next
= pgd_addr_end(addr
, end
);
1804 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1807 } while (pgd
++, addr
= next
, addr
!= end
);
1808 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1811 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1814 * handle_pte_fault chooses page fault handler according to an entry
1815 * which was read non-atomically. Before making any commitment, on
1816 * those architectures or configurations (e.g. i386 with PAE) which
1817 * might give a mix of unmatched parts, do_swap_page and do_file_page
1818 * must check under lock before unmapping the pte and proceeding
1819 * (but do_wp_page is only called after already making such a check;
1820 * and do_anonymous_page and do_no_page can safely check later on).
1822 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1823 pte_t
*page_table
, pte_t orig_pte
)
1826 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1827 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1828 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1830 same
= pte_same(*page_table
, orig_pte
);
1834 pte_unmap(page_table
);
1839 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1840 * servicing faults for write access. In the normal case, do always want
1841 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1842 * that do not have writing enabled, when used by access_process_vm.
1844 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1846 if (likely(vma
->vm_flags
& VM_WRITE
))
1847 pte
= pte_mkwrite(pte
);
1851 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1854 * If the source page was a PFN mapping, we don't have
1855 * a "struct page" for it. We do a best-effort copy by
1856 * just copying from the original user address. If that
1857 * fails, we just zero-fill it. Live with it.
1859 if (unlikely(!src
)) {
1860 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1861 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1864 * This really shouldn't fail, because the page is there
1865 * in the page tables. But it might just be unreadable,
1866 * in which case we just give up and fill the result with
1869 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1870 memset(kaddr
, 0, PAGE_SIZE
);
1871 kunmap_atomic(kaddr
, KM_USER0
);
1872 flush_dcache_page(dst
);
1874 copy_user_highpage(dst
, src
, va
, vma
);
1878 * This routine handles present pages, when users try to write
1879 * to a shared page. It is done by copying the page to a new address
1880 * and decrementing the shared-page counter for the old page.
1882 * Note that this routine assumes that the protection checks have been
1883 * done by the caller (the low-level page fault routine in most cases).
1884 * Thus we can safely just mark it writable once we've done any necessary
1887 * We also mark the page dirty at this point even though the page will
1888 * change only once the write actually happens. This avoids a few races,
1889 * and potentially makes it more efficient.
1891 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1892 * but allow concurrent faults), with pte both mapped and locked.
1893 * We return with mmap_sem still held, but pte unmapped and unlocked.
1895 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1896 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1897 spinlock_t
*ptl
, pte_t orig_pte
)
1899 struct page
*old_page
, *new_page
;
1901 int reuse
= 0, ret
= 0;
1902 int page_mkwrite
= 0;
1903 struct page
*dirty_page
= NULL
;
1905 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1908 * VM_MIXEDMAP !pfn_valid() case
1910 * We should not cow pages in a shared writeable mapping.
1911 * Just mark the pages writable as we can't do any dirty
1912 * accounting on raw pfn maps.
1914 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1915 (VM_WRITE
|VM_SHARED
))
1921 * Take out anonymous pages first, anonymous shared vmas are
1922 * not dirty accountable.
1924 if (PageAnon(old_page
)) {
1925 if (!trylock_page(old_page
)) {
1926 page_cache_get(old_page
);
1927 pte_unmap_unlock(page_table
, ptl
);
1928 lock_page(old_page
);
1929 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1931 if (!pte_same(*page_table
, orig_pte
)) {
1932 unlock_page(old_page
);
1933 page_cache_release(old_page
);
1936 page_cache_release(old_page
);
1938 reuse
= reuse_swap_page(old_page
);
1939 unlock_page(old_page
);
1940 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1941 (VM_WRITE
|VM_SHARED
))) {
1943 * Only catch write-faults on shared writable pages,
1944 * read-only shared pages can get COWed by
1945 * get_user_pages(.write=1, .force=1).
1947 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
1949 * Notify the address space that the page is about to
1950 * become writable so that it can prohibit this or wait
1951 * for the page to get into an appropriate state.
1953 * We do this without the lock held, so that it can
1954 * sleep if it needs to.
1956 page_cache_get(old_page
);
1957 pte_unmap_unlock(page_table
, ptl
);
1959 if (vma
->vm_ops
->page_mkwrite(vma
, old_page
) < 0)
1960 goto unwritable_page
;
1963 * Since we dropped the lock we need to revalidate
1964 * the PTE as someone else may have changed it. If
1965 * they did, we just return, as we can count on the
1966 * MMU to tell us if they didn't also make it writable.
1968 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1970 page_cache_release(old_page
);
1971 if (!pte_same(*page_table
, orig_pte
))
1976 dirty_page
= old_page
;
1977 get_page(dirty_page
);
1983 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
1984 entry
= pte_mkyoung(orig_pte
);
1985 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1986 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1))
1987 update_mmu_cache(vma
, address
, entry
);
1988 ret
|= VM_FAULT_WRITE
;
1993 * Ok, we need to copy. Oh, well..
1995 page_cache_get(old_page
);
1997 pte_unmap_unlock(page_table
, ptl
);
1999 if (unlikely(anon_vma_prepare(vma
)))
2001 VM_BUG_ON(old_page
== ZERO_PAGE(0));
2002 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
2006 * Don't let another task, with possibly unlocked vma,
2007 * keep the mlocked page.
2009 if ((vma
->vm_flags
& VM_LOCKED
) && old_page
) {
2010 lock_page(old_page
); /* for LRU manipulation */
2011 clear_page_mlock(old_page
);
2012 unlock_page(old_page
);
2014 cow_user_page(new_page
, old_page
, address
, vma
);
2015 __SetPageUptodate(new_page
);
2017 if (mem_cgroup_newpage_charge(new_page
, mm
, GFP_KERNEL
))
2021 * Re-check the pte - we dropped the lock
2023 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2024 if (likely(pte_same(*page_table
, orig_pte
))) {
2026 if (!PageAnon(old_page
)) {
2027 dec_mm_counter(mm
, file_rss
);
2028 inc_mm_counter(mm
, anon_rss
);
2031 inc_mm_counter(mm
, anon_rss
);
2032 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2033 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2034 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2036 * Clear the pte entry and flush it first, before updating the
2037 * pte with the new entry. This will avoid a race condition
2038 * seen in the presence of one thread doing SMC and another
2041 ptep_clear_flush_notify(vma
, address
, page_table
);
2042 page_add_new_anon_rmap(new_page
, vma
, address
);
2043 set_pte_at(mm
, address
, page_table
, entry
);
2044 update_mmu_cache(vma
, address
, entry
);
2047 * Only after switching the pte to the new page may
2048 * we remove the mapcount here. Otherwise another
2049 * process may come and find the rmap count decremented
2050 * before the pte is switched to the new page, and
2051 * "reuse" the old page writing into it while our pte
2052 * here still points into it and can be read by other
2055 * The critical issue is to order this
2056 * page_remove_rmap with the ptp_clear_flush above.
2057 * Those stores are ordered by (if nothing else,)
2058 * the barrier present in the atomic_add_negative
2059 * in page_remove_rmap.
2061 * Then the TLB flush in ptep_clear_flush ensures that
2062 * no process can access the old page before the
2063 * decremented mapcount is visible. And the old page
2064 * cannot be reused until after the decremented
2065 * mapcount is visible. So transitively, TLBs to
2066 * old page will be flushed before it can be reused.
2068 page_remove_rmap(old_page
);
2071 /* Free the old page.. */
2072 new_page
= old_page
;
2073 ret
|= VM_FAULT_WRITE
;
2075 mem_cgroup_uncharge_page(new_page
);
2078 page_cache_release(new_page
);
2080 page_cache_release(old_page
);
2082 pte_unmap_unlock(page_table
, ptl
);
2085 file_update_time(vma
->vm_file
);
2088 * Yes, Virginia, this is actually required to prevent a race
2089 * with clear_page_dirty_for_io() from clearing the page dirty
2090 * bit after it clear all dirty ptes, but before a racing
2091 * do_wp_page installs a dirty pte.
2093 * do_no_page is protected similarly.
2095 wait_on_page_locked(dirty_page
);
2096 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2097 put_page(dirty_page
);
2101 page_cache_release(new_page
);
2104 page_cache_release(old_page
);
2105 return VM_FAULT_OOM
;
2108 page_cache_release(old_page
);
2109 return VM_FAULT_SIGBUS
;
2113 * Helper functions for unmap_mapping_range().
2115 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2117 * We have to restart searching the prio_tree whenever we drop the lock,
2118 * since the iterator is only valid while the lock is held, and anyway
2119 * a later vma might be split and reinserted earlier while lock dropped.
2121 * The list of nonlinear vmas could be handled more efficiently, using
2122 * a placeholder, but handle it in the same way until a need is shown.
2123 * It is important to search the prio_tree before nonlinear list: a vma
2124 * may become nonlinear and be shifted from prio_tree to nonlinear list
2125 * while the lock is dropped; but never shifted from list to prio_tree.
2127 * In order to make forward progress despite restarting the search,
2128 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2129 * quickly skip it next time around. Since the prio_tree search only
2130 * shows us those vmas affected by unmapping the range in question, we
2131 * can't efficiently keep all vmas in step with mapping->truncate_count:
2132 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2133 * mapping->truncate_count and vma->vm_truncate_count are protected by
2136 * In order to make forward progress despite repeatedly restarting some
2137 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2138 * and restart from that address when we reach that vma again. It might
2139 * have been split or merged, shrunk or extended, but never shifted: so
2140 * restart_addr remains valid so long as it remains in the vma's range.
2141 * unmap_mapping_range forces truncate_count to leap over page-aligned
2142 * values so we can save vma's restart_addr in its truncate_count field.
2144 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2146 static void reset_vma_truncate_counts(struct address_space
*mapping
)
2148 struct vm_area_struct
*vma
;
2149 struct prio_tree_iter iter
;
2151 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
2152 vma
->vm_truncate_count
= 0;
2153 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
2154 vma
->vm_truncate_count
= 0;
2157 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2158 unsigned long start_addr
, unsigned long end_addr
,
2159 struct zap_details
*details
)
2161 unsigned long restart_addr
;
2165 * files that support invalidating or truncating portions of the
2166 * file from under mmaped areas must have their ->fault function
2167 * return a locked page (and set VM_FAULT_LOCKED in the return).
2168 * This provides synchronisation against concurrent unmapping here.
2172 restart_addr
= vma
->vm_truncate_count
;
2173 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
2174 start_addr
= restart_addr
;
2175 if (start_addr
>= end_addr
) {
2176 /* Top of vma has been split off since last time */
2177 vma
->vm_truncate_count
= details
->truncate_count
;
2182 restart_addr
= zap_page_range(vma
, start_addr
,
2183 end_addr
- start_addr
, details
);
2184 need_break
= need_resched() || spin_needbreak(details
->i_mmap_lock
);
2186 if (restart_addr
>= end_addr
) {
2187 /* We have now completed this vma: mark it so */
2188 vma
->vm_truncate_count
= details
->truncate_count
;
2192 /* Note restart_addr in vma's truncate_count field */
2193 vma
->vm_truncate_count
= restart_addr
;
2198 spin_unlock(details
->i_mmap_lock
);
2200 spin_lock(details
->i_mmap_lock
);
2204 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
2205 struct zap_details
*details
)
2207 struct vm_area_struct
*vma
;
2208 struct prio_tree_iter iter
;
2209 pgoff_t vba
, vea
, zba
, zea
;
2212 vma_prio_tree_foreach(vma
, &iter
, root
,
2213 details
->first_index
, details
->last_index
) {
2214 /* Skip quickly over those we have already dealt with */
2215 if (vma
->vm_truncate_count
== details
->truncate_count
)
2218 vba
= vma
->vm_pgoff
;
2219 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
2220 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2221 zba
= details
->first_index
;
2224 zea
= details
->last_index
;
2228 if (unmap_mapping_range_vma(vma
,
2229 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2230 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2236 static inline void unmap_mapping_range_list(struct list_head
*head
,
2237 struct zap_details
*details
)
2239 struct vm_area_struct
*vma
;
2242 * In nonlinear VMAs there is no correspondence between virtual address
2243 * offset and file offset. So we must perform an exhaustive search
2244 * across *all* the pages in each nonlinear VMA, not just the pages
2245 * whose virtual address lies outside the file truncation point.
2248 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
2249 /* Skip quickly over those we have already dealt with */
2250 if (vma
->vm_truncate_count
== details
->truncate_count
)
2252 details
->nonlinear_vma
= vma
;
2253 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
2254 vma
->vm_end
, details
) < 0)
2260 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2261 * @mapping: the address space containing mmaps to be unmapped.
2262 * @holebegin: byte in first page to unmap, relative to the start of
2263 * the underlying file. This will be rounded down to a PAGE_SIZE
2264 * boundary. Note that this is different from vmtruncate(), which
2265 * must keep the partial page. In contrast, we must get rid of
2267 * @holelen: size of prospective hole in bytes. This will be rounded
2268 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2270 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2271 * but 0 when invalidating pagecache, don't throw away private data.
2273 void unmap_mapping_range(struct address_space
*mapping
,
2274 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2276 struct zap_details details
;
2277 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2278 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2280 /* Check for overflow. */
2281 if (sizeof(holelen
) > sizeof(hlen
)) {
2283 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2284 if (holeend
& ~(long long)ULONG_MAX
)
2285 hlen
= ULONG_MAX
- hba
+ 1;
2288 details
.check_mapping
= even_cows
? NULL
: mapping
;
2289 details
.nonlinear_vma
= NULL
;
2290 details
.first_index
= hba
;
2291 details
.last_index
= hba
+ hlen
- 1;
2292 if (details
.last_index
< details
.first_index
)
2293 details
.last_index
= ULONG_MAX
;
2294 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
2296 spin_lock(&mapping
->i_mmap_lock
);
2298 /* Protect against endless unmapping loops */
2299 mapping
->truncate_count
++;
2300 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
2301 if (mapping
->truncate_count
== 0)
2302 reset_vma_truncate_counts(mapping
);
2303 mapping
->truncate_count
++;
2305 details
.truncate_count
= mapping
->truncate_count
;
2307 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
2308 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2309 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
2310 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
2311 spin_unlock(&mapping
->i_mmap_lock
);
2313 EXPORT_SYMBOL(unmap_mapping_range
);
2316 * vmtruncate - unmap mappings "freed" by truncate() syscall
2317 * @inode: inode of the file used
2318 * @offset: file offset to start truncating
2320 * NOTE! We have to be ready to update the memory sharing
2321 * between the file and the memory map for a potential last
2322 * incomplete page. Ugly, but necessary.
2324 int vmtruncate(struct inode
* inode
, loff_t offset
)
2326 if (inode
->i_size
< offset
) {
2327 unsigned long limit
;
2329 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
2330 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
2332 if (offset
> inode
->i_sb
->s_maxbytes
)
2334 i_size_write(inode
, offset
);
2336 struct address_space
*mapping
= inode
->i_mapping
;
2339 * truncation of in-use swapfiles is disallowed - it would
2340 * cause subsequent swapout to scribble on the now-freed
2343 if (IS_SWAPFILE(inode
))
2345 i_size_write(inode
, offset
);
2348 * unmap_mapping_range is called twice, first simply for
2349 * efficiency so that truncate_inode_pages does fewer
2350 * single-page unmaps. However after this first call, and
2351 * before truncate_inode_pages finishes, it is possible for
2352 * private pages to be COWed, which remain after
2353 * truncate_inode_pages finishes, hence the second
2354 * unmap_mapping_range call must be made for correctness.
2356 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2357 truncate_inode_pages(mapping
, offset
);
2358 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2361 if (inode
->i_op
->truncate
)
2362 inode
->i_op
->truncate(inode
);
2366 send_sig(SIGXFSZ
, current
, 0);
2370 EXPORT_SYMBOL(vmtruncate
);
2372 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
2374 struct address_space
*mapping
= inode
->i_mapping
;
2377 * If the underlying filesystem is not going to provide
2378 * a way to truncate a range of blocks (punch a hole) -
2379 * we should return failure right now.
2381 if (!inode
->i_op
->truncate_range
)
2384 mutex_lock(&inode
->i_mutex
);
2385 down_write(&inode
->i_alloc_sem
);
2386 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2387 truncate_inode_pages_range(mapping
, offset
, end
);
2388 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2389 inode
->i_op
->truncate_range(inode
, offset
, end
);
2390 up_write(&inode
->i_alloc_sem
);
2391 mutex_unlock(&inode
->i_mutex
);
2397 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2398 * but allow concurrent faults), and pte mapped but not yet locked.
2399 * We return with mmap_sem still held, but pte unmapped and unlocked.
2401 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2402 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2403 int write_access
, pte_t orig_pte
)
2409 struct mem_cgroup
*ptr
= NULL
;
2412 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2415 entry
= pte_to_swp_entry(orig_pte
);
2416 if (is_migration_entry(entry
)) {
2417 migration_entry_wait(mm
, pmd
, address
);
2420 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2421 page
= lookup_swap_cache(entry
);
2423 grab_swap_token(); /* Contend for token _before_ read-in */
2424 page
= swapin_readahead(entry
,
2425 GFP_HIGHUSER_MOVABLE
, vma
, address
);
2428 * Back out if somebody else faulted in this pte
2429 * while we released the pte lock.
2431 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2432 if (likely(pte_same(*page_table
, orig_pte
)))
2434 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2438 /* Had to read the page from swap area: Major fault */
2439 ret
= VM_FAULT_MAJOR
;
2440 count_vm_event(PGMAJFAULT
);
2444 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2446 if (mem_cgroup_try_charge_swapin(mm
, page
, GFP_KERNEL
, &ptr
)) {
2453 * Back out if somebody else already faulted in this pte.
2455 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2456 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2459 if (unlikely(!PageUptodate(page
))) {
2460 ret
= VM_FAULT_SIGBUS
;
2465 * The page isn't present yet, go ahead with the fault.
2467 * Be careful about the sequence of operations here.
2468 * To get its accounting right, reuse_swap_page() must be called
2469 * while the page is counted on swap but not yet in mapcount i.e.
2470 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2471 * must be called after the swap_free(), or it will never succeed.
2472 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2473 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2474 * in page->private. In this case, a record in swap_cgroup is silently
2475 * discarded at swap_free().
2478 inc_mm_counter(mm
, anon_rss
);
2479 pte
= mk_pte(page
, vma
->vm_page_prot
);
2480 if (write_access
&& reuse_swap_page(page
)) {
2481 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2484 flush_icache_page(vma
, page
);
2485 set_pte_at(mm
, address
, page_table
, pte
);
2486 page_add_anon_rmap(page
, vma
, address
);
2487 /* It's better to call commit-charge after rmap is established */
2488 mem_cgroup_commit_charge_swapin(page
, ptr
);
2491 if (vm_swap_full() || (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
2492 try_to_free_swap(page
);
2496 ret
|= do_wp_page(mm
, vma
, address
, page_table
, pmd
, ptl
, pte
);
2497 if (ret
& VM_FAULT_ERROR
)
2498 ret
&= VM_FAULT_ERROR
;
2502 /* No need to invalidate - it was non-present before */
2503 update_mmu_cache(vma
, address
, pte
);
2505 pte_unmap_unlock(page_table
, ptl
);
2509 mem_cgroup_cancel_charge_swapin(ptr
);
2510 pte_unmap_unlock(page_table
, ptl
);
2512 page_cache_release(page
);
2517 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2518 * but allow concurrent faults), and pte mapped but not yet locked.
2519 * We return with mmap_sem still held, but pte unmapped and unlocked.
2521 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2522 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2529 /* Allocate our own private page. */
2530 pte_unmap(page_table
);
2532 if (unlikely(anon_vma_prepare(vma
)))
2534 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2537 __SetPageUptodate(page
);
2539 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
))
2542 entry
= mk_pte(page
, vma
->vm_page_prot
);
2543 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2545 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2546 if (!pte_none(*page_table
))
2548 inc_mm_counter(mm
, anon_rss
);
2549 page_add_new_anon_rmap(page
, vma
, address
);
2550 set_pte_at(mm
, address
, page_table
, entry
);
2552 /* No need to invalidate - it was non-present before */
2553 update_mmu_cache(vma
, address
, entry
);
2555 pte_unmap_unlock(page_table
, ptl
);
2558 mem_cgroup_uncharge_page(page
);
2559 page_cache_release(page
);
2562 page_cache_release(page
);
2564 return VM_FAULT_OOM
;
2568 * __do_fault() tries to create a new page mapping. It aggressively
2569 * tries to share with existing pages, but makes a separate copy if
2570 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2571 * the next page fault.
2573 * As this is called only for pages that do not currently exist, we
2574 * do not need to flush old virtual caches or the TLB.
2576 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2577 * but allow concurrent faults), and pte neither mapped nor locked.
2578 * We return with mmap_sem still held, but pte unmapped and unlocked.
2580 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2581 unsigned long address
, pmd_t
*pmd
,
2582 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
2590 struct page
*dirty_page
= NULL
;
2591 struct vm_fault vmf
;
2593 int page_mkwrite
= 0;
2595 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
2600 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
2601 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2605 * For consistency in subsequent calls, make the faulted page always
2608 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
2609 lock_page(vmf
.page
);
2611 VM_BUG_ON(!PageLocked(vmf
.page
));
2614 * Should we do an early C-O-W break?
2617 if (flags
& FAULT_FLAG_WRITE
) {
2618 if (!(vma
->vm_flags
& VM_SHARED
)) {
2620 if (unlikely(anon_vma_prepare(vma
))) {
2624 page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
,
2630 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
)) {
2632 page_cache_release(page
);
2637 * Don't let another task, with possibly unlocked vma,
2638 * keep the mlocked page.
2640 if (vma
->vm_flags
& VM_LOCKED
)
2641 clear_page_mlock(vmf
.page
);
2642 copy_user_highpage(page
, vmf
.page
, address
, vma
);
2643 __SetPageUptodate(page
);
2646 * If the page will be shareable, see if the backing
2647 * address space wants to know that the page is about
2648 * to become writable
2650 if (vma
->vm_ops
->page_mkwrite
) {
2652 if (vma
->vm_ops
->page_mkwrite(vma
, page
) < 0) {
2653 ret
= VM_FAULT_SIGBUS
;
2654 anon
= 1; /* no anon but release vmf.page */
2659 * XXX: this is not quite right (racy vs
2660 * invalidate) to unlock and relock the page
2661 * like this, however a better fix requires
2662 * reworking page_mkwrite locking API, which
2663 * is better done later.
2665 if (!page
->mapping
) {
2667 anon
= 1; /* no anon but release vmf.page */
2676 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2679 * This silly early PAGE_DIRTY setting removes a race
2680 * due to the bad i386 page protection. But it's valid
2681 * for other architectures too.
2683 * Note that if write_access is true, we either now have
2684 * an exclusive copy of the page, or this is a shared mapping,
2685 * so we can make it writable and dirty to avoid having to
2686 * handle that later.
2688 /* Only go through if we didn't race with anybody else... */
2689 if (likely(pte_same(*page_table
, orig_pte
))) {
2690 flush_icache_page(vma
, page
);
2691 entry
= mk_pte(page
, vma
->vm_page_prot
);
2692 if (flags
& FAULT_FLAG_WRITE
)
2693 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2695 inc_mm_counter(mm
, anon_rss
);
2696 page_add_new_anon_rmap(page
, vma
, address
);
2698 inc_mm_counter(mm
, file_rss
);
2699 page_add_file_rmap(page
);
2700 if (flags
& FAULT_FLAG_WRITE
) {
2702 get_page(dirty_page
);
2705 set_pte_at(mm
, address
, page_table
, entry
);
2707 /* no need to invalidate: a not-present page won't be cached */
2708 update_mmu_cache(vma
, address
, entry
);
2711 mem_cgroup_uncharge_page(page
);
2713 page_cache_release(page
);
2715 anon
= 1; /* no anon but release faulted_page */
2718 pte_unmap_unlock(page_table
, ptl
);
2721 unlock_page(vmf
.page
);
2724 page_cache_release(vmf
.page
);
2725 else if (dirty_page
) {
2727 file_update_time(vma
->vm_file
);
2729 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2730 put_page(dirty_page
);
2736 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2737 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2738 int write_access
, pte_t orig_pte
)
2740 pgoff_t pgoff
= (((address
& PAGE_MASK
)
2741 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2742 unsigned int flags
= (write_access
? FAULT_FLAG_WRITE
: 0);
2744 pte_unmap(page_table
);
2745 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2749 * Fault of a previously existing named mapping. Repopulate the pte
2750 * from the encoded file_pte if possible. This enables swappable
2753 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2754 * but allow concurrent faults), and pte mapped but not yet locked.
2755 * We return with mmap_sem still held, but pte unmapped and unlocked.
2757 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2758 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2759 int write_access
, pte_t orig_pte
)
2761 unsigned int flags
= FAULT_FLAG_NONLINEAR
|
2762 (write_access
? FAULT_FLAG_WRITE
: 0);
2765 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2768 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
2770 * Page table corrupted: show pte and kill process.
2772 print_bad_pte(vma
, address
, orig_pte
, NULL
);
2773 return VM_FAULT_OOM
;
2776 pgoff
= pte_to_pgoff(orig_pte
);
2777 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2781 * These routines also need to handle stuff like marking pages dirty
2782 * and/or accessed for architectures that don't do it in hardware (most
2783 * RISC architectures). The early dirtying is also good on the i386.
2785 * There is also a hook called "update_mmu_cache()" that architectures
2786 * with external mmu caches can use to update those (ie the Sparc or
2787 * PowerPC hashed page tables that act as extended TLBs).
2789 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2790 * but allow concurrent faults), and pte mapped but not yet locked.
2791 * We return with mmap_sem still held, but pte unmapped and unlocked.
2793 static inline int handle_pte_fault(struct mm_struct
*mm
,
2794 struct vm_area_struct
*vma
, unsigned long address
,
2795 pte_t
*pte
, pmd_t
*pmd
, int write_access
)
2801 if (!pte_present(entry
)) {
2802 if (pte_none(entry
)) {
2804 if (likely(vma
->vm_ops
->fault
))
2805 return do_linear_fault(mm
, vma
, address
,
2806 pte
, pmd
, write_access
, entry
);
2808 return do_anonymous_page(mm
, vma
, address
,
2809 pte
, pmd
, write_access
);
2811 if (pte_file(entry
))
2812 return do_nonlinear_fault(mm
, vma
, address
,
2813 pte
, pmd
, write_access
, entry
);
2814 return do_swap_page(mm
, vma
, address
,
2815 pte
, pmd
, write_access
, entry
);
2818 ptl
= pte_lockptr(mm
, pmd
);
2820 if (unlikely(!pte_same(*pte
, entry
)))
2823 if (!pte_write(entry
))
2824 return do_wp_page(mm
, vma
, address
,
2825 pte
, pmd
, ptl
, entry
);
2826 entry
= pte_mkdirty(entry
);
2828 entry
= pte_mkyoung(entry
);
2829 if (ptep_set_access_flags(vma
, address
, pte
, entry
, write_access
)) {
2830 update_mmu_cache(vma
, address
, entry
);
2833 * This is needed only for protection faults but the arch code
2834 * is not yet telling us if this is a protection fault or not.
2835 * This still avoids useless tlb flushes for .text page faults
2839 flush_tlb_page(vma
, address
);
2842 pte_unmap_unlock(pte
, ptl
);
2847 * By the time we get here, we already hold the mm semaphore
2849 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2850 unsigned long address
, int write_access
)
2857 __set_current_state(TASK_RUNNING
);
2859 count_vm_event(PGFAULT
);
2861 if (unlikely(is_vm_hugetlb_page(vma
)))
2862 return hugetlb_fault(mm
, vma
, address
, write_access
);
2864 pgd
= pgd_offset(mm
, address
);
2865 pud
= pud_alloc(mm
, pgd
, address
);
2867 return VM_FAULT_OOM
;
2868 pmd
= pmd_alloc(mm
, pud
, address
);
2870 return VM_FAULT_OOM
;
2871 pte
= pte_alloc_map(mm
, pmd
, address
);
2873 return VM_FAULT_OOM
;
2875 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, write_access
);
2878 #ifndef __PAGETABLE_PUD_FOLDED
2880 * Allocate page upper directory.
2881 * We've already handled the fast-path in-line.
2883 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
2885 pud_t
*new = pud_alloc_one(mm
, address
);
2889 smp_wmb(); /* See comment in __pte_alloc */
2891 spin_lock(&mm
->page_table_lock
);
2892 if (pgd_present(*pgd
)) /* Another has populated it */
2895 pgd_populate(mm
, pgd
, new);
2896 spin_unlock(&mm
->page_table_lock
);
2899 #endif /* __PAGETABLE_PUD_FOLDED */
2901 #ifndef __PAGETABLE_PMD_FOLDED
2903 * Allocate page middle directory.
2904 * We've already handled the fast-path in-line.
2906 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
2908 pmd_t
*new = pmd_alloc_one(mm
, address
);
2912 smp_wmb(); /* See comment in __pte_alloc */
2914 spin_lock(&mm
->page_table_lock
);
2915 #ifndef __ARCH_HAS_4LEVEL_HACK
2916 if (pud_present(*pud
)) /* Another has populated it */
2919 pud_populate(mm
, pud
, new);
2921 if (pgd_present(*pud
)) /* Another has populated it */
2924 pgd_populate(mm
, pud
, new);
2925 #endif /* __ARCH_HAS_4LEVEL_HACK */
2926 spin_unlock(&mm
->page_table_lock
);
2929 #endif /* __PAGETABLE_PMD_FOLDED */
2931 int make_pages_present(unsigned long addr
, unsigned long end
)
2933 int ret
, len
, write
;
2934 struct vm_area_struct
* vma
;
2936 vma
= find_vma(current
->mm
, addr
);
2939 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
2940 BUG_ON(addr
>= end
);
2941 BUG_ON(end
> vma
->vm_end
);
2942 len
= DIV_ROUND_UP(end
, PAGE_SIZE
) - addr
/PAGE_SIZE
;
2943 ret
= get_user_pages(current
, current
->mm
, addr
,
2944 len
, write
, 0, NULL
, NULL
);
2947 return ret
== len
? 0 : -EFAULT
;
2950 #if !defined(__HAVE_ARCH_GATE_AREA)
2952 #if defined(AT_SYSINFO_EHDR)
2953 static struct vm_area_struct gate_vma
;
2955 static int __init
gate_vma_init(void)
2957 gate_vma
.vm_mm
= NULL
;
2958 gate_vma
.vm_start
= FIXADDR_USER_START
;
2959 gate_vma
.vm_end
= FIXADDR_USER_END
;
2960 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
2961 gate_vma
.vm_page_prot
= __P101
;
2963 * Make sure the vDSO gets into every core dump.
2964 * Dumping its contents makes post-mortem fully interpretable later
2965 * without matching up the same kernel and hardware config to see
2966 * what PC values meant.
2968 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
2971 __initcall(gate_vma_init
);
2974 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
2976 #ifdef AT_SYSINFO_EHDR
2983 int in_gate_area_no_task(unsigned long addr
)
2985 #ifdef AT_SYSINFO_EHDR
2986 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
2992 #endif /* __HAVE_ARCH_GATE_AREA */
2994 #ifdef CONFIG_HAVE_IOREMAP_PROT
2995 int follow_phys(struct vm_area_struct
*vma
,
2996 unsigned long address
, unsigned int flags
,
2997 unsigned long *prot
, resource_size_t
*phys
)
3004 resource_size_t phys_addr
= 0;
3005 struct mm_struct
*mm
= vma
->vm_mm
;
3008 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3011 pgd
= pgd_offset(mm
, address
);
3012 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
3015 pud
= pud_offset(pgd
, address
);
3016 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
3019 pmd
= pmd_offset(pud
, address
);
3020 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
3023 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3027 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
3032 if (!pte_present(pte
))
3034 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
3036 phys_addr
= pte_pfn(pte
);
3037 phys_addr
<<= PAGE_SHIFT
; /* Shift here to avoid overflow on PAE */
3039 *prot
= pgprot_val(pte_pgprot(pte
));
3044 pte_unmap_unlock(ptep
, ptl
);
3049 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
3050 void *buf
, int len
, int write
)
3052 resource_size_t phys_addr
;
3053 unsigned long prot
= 0;
3054 void __iomem
*maddr
;
3055 int offset
= addr
& (PAGE_SIZE
-1);
3057 if (follow_phys(vma
, addr
, write
, &prot
, &phys_addr
))
3060 maddr
= ioremap_prot(phys_addr
, PAGE_SIZE
, prot
);
3062 memcpy_toio(maddr
+ offset
, buf
, len
);
3064 memcpy_fromio(buf
, maddr
+ offset
, len
);
3072 * Access another process' address space.
3073 * Source/target buffer must be kernel space,
3074 * Do not walk the page table directly, use get_user_pages
3076 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
3078 struct mm_struct
*mm
;
3079 struct vm_area_struct
*vma
;
3080 void *old_buf
= buf
;
3082 mm
= get_task_mm(tsk
);
3086 down_read(&mm
->mmap_sem
);
3087 /* ignore errors, just check how much was successfully transferred */
3089 int bytes
, ret
, offset
;
3091 struct page
*page
= NULL
;
3093 ret
= get_user_pages(tsk
, mm
, addr
, 1,
3094 write
, 1, &page
, &vma
);
3097 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3098 * we can access using slightly different code.
3100 #ifdef CONFIG_HAVE_IOREMAP_PROT
3101 vma
= find_vma(mm
, addr
);
3104 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
3105 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
3113 offset
= addr
& (PAGE_SIZE
-1);
3114 if (bytes
> PAGE_SIZE
-offset
)
3115 bytes
= PAGE_SIZE
-offset
;
3119 copy_to_user_page(vma
, page
, addr
,
3120 maddr
+ offset
, buf
, bytes
);
3121 set_page_dirty_lock(page
);
3123 copy_from_user_page(vma
, page
, addr
,
3124 buf
, maddr
+ offset
, bytes
);
3127 page_cache_release(page
);
3133 up_read(&mm
->mmap_sem
);
3136 return buf
- old_buf
;
3140 * Print the name of a VMA.
3142 void print_vma_addr(char *prefix
, unsigned long ip
)
3144 struct mm_struct
*mm
= current
->mm
;
3145 struct vm_area_struct
*vma
;
3148 * Do not print if we are in atomic
3149 * contexts (in exception stacks, etc.):
3151 if (preempt_count())
3154 down_read(&mm
->mmap_sem
);
3155 vma
= find_vma(mm
, ip
);
3156 if (vma
&& vma
->vm_file
) {
3157 struct file
*f
= vma
->vm_file
;
3158 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
3162 p
= d_path(&f
->f_path
, buf
, PAGE_SIZE
);
3165 s
= strrchr(p
, '/');
3168 printk("%s%s[%lx+%lx]", prefix
, p
,
3170 vma
->vm_end
- vma
->vm_start
);
3171 free_page((unsigned long)buf
);
3174 up_read(¤t
->mm
->mmap_sem
);
3177 #ifdef CONFIG_PROVE_LOCKING
3178 void might_fault(void)
3181 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3182 * holding the mmap_sem, this is safe because kernel memory doesn't
3183 * get paged out, therefore we'll never actually fault, and the
3184 * below annotations will generate false positives.
3186 if (segment_eq(get_fs(), KERNEL_DS
))
3191 * it would be nicer only to annotate paths which are not under
3192 * pagefault_disable, however that requires a larger audit and
3193 * providing helpers like get_user_atomic.
3195 if (!in_atomic() && current
->mm
)
3196 might_lock_read(¤t
->mm
->mmap_sem
);
3198 EXPORT_SYMBOL(might_fault
);