4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
8 * demand-loading started 01.12.91 - seems it is high on the list of
9 * things wanted, and it should be easy to implement. - Linus
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 * would have taken more than the 6M I have free, but it worked well as
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
24 * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 * thought has to go into this. Oh, well..
26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 * Found it. Everything seems to work now.
28 * 20.12.91 - Ok, making the swap-device changeable like the root.
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
41 #include <linux/kernel_stat.h>
43 #include <linux/hugetlb.h>
44 #include <linux/mman.h>
45 #include <linux/swap.h>
46 #include <linux/highmem.h>
47 #include <linux/pagemap.h>
48 #include <linux/ksm.h>
49 #include <linux/rmap.h>
50 #include <linux/module.h>
51 #include <linux/delayacct.h>
52 #include <linux/init.h>
53 #include <linux/writeback.h>
54 #include <linux/memcontrol.h>
55 #include <linux/mmu_notifier.h>
56 #include <linux/kallsyms.h>
57 #include <linux/swapops.h>
58 #include <linux/elf.h>
61 #include <asm/pgalloc.h>
62 #include <asm/uaccess.h>
64 #include <asm/tlbflush.h>
65 #include <asm/pgtable.h>
69 #ifndef CONFIG_NEED_MULTIPLE_NODES
70 /* use the per-pgdat data instead for discontigmem - mbligh */
71 unsigned long max_mapnr
;
74 EXPORT_SYMBOL(max_mapnr
);
75 EXPORT_SYMBOL(mem_map
);
78 unsigned long num_physpages
;
80 * A number of key systems in x86 including ioremap() rely on the assumption
81 * that high_memory defines the upper bound on direct map memory, then end
82 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
83 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
88 EXPORT_SYMBOL(num_physpages
);
89 EXPORT_SYMBOL(high_memory
);
92 * Randomize the address space (stacks, mmaps, brk, etc.).
94 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
95 * as ancient (libc5 based) binaries can segfault. )
97 int randomize_va_space __read_mostly
=
98 #ifdef CONFIG_COMPAT_BRK
104 static int __init
disable_randmaps(char *s
)
106 randomize_va_space
= 0;
109 __setup("norandmaps", disable_randmaps
);
113 * If a p?d_bad entry is found while walking page tables, report
114 * the error, before resetting entry to p?d_none. Usually (but
115 * very seldom) called out from the p?d_none_or_clear_bad macros.
118 void pgd_clear_bad(pgd_t
*pgd
)
124 void pud_clear_bad(pud_t
*pud
)
130 void pmd_clear_bad(pmd_t
*pmd
)
137 * Note: this doesn't free the actual pages themselves. That
138 * has been handled earlier when unmapping all the memory regions.
140 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
,
143 pgtable_t token
= pmd_pgtable(*pmd
);
145 pte_free_tlb(tlb
, token
, addr
);
149 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
150 unsigned long addr
, unsigned long end
,
151 unsigned long floor
, unsigned long ceiling
)
158 pmd
= pmd_offset(pud
, addr
);
160 next
= pmd_addr_end(addr
, end
);
161 if (pmd_none_or_clear_bad(pmd
))
163 free_pte_range(tlb
, pmd
, addr
);
164 } while (pmd
++, addr
= next
, addr
!= end
);
174 if (end
- 1 > ceiling
- 1)
177 pmd
= pmd_offset(pud
, start
);
179 pmd_free_tlb(tlb
, pmd
, start
);
182 static inline void free_pud_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
183 unsigned long addr
, unsigned long end
,
184 unsigned long floor
, unsigned long ceiling
)
191 pud
= pud_offset(pgd
, addr
);
193 next
= pud_addr_end(addr
, end
);
194 if (pud_none_or_clear_bad(pud
))
196 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
197 } while (pud
++, addr
= next
, addr
!= end
);
203 ceiling
&= PGDIR_MASK
;
207 if (end
- 1 > ceiling
- 1)
210 pud
= pud_offset(pgd
, start
);
212 pud_free_tlb(tlb
, pud
, start
);
216 * This function frees user-level page tables of a process.
218 * Must be called with pagetable lock held.
220 void free_pgd_range(struct mmu_gather
*tlb
,
221 unsigned long addr
, unsigned long end
,
222 unsigned long floor
, unsigned long ceiling
)
229 * The next few lines have given us lots of grief...
231 * Why are we testing PMD* at this top level? Because often
232 * there will be no work to do at all, and we'd prefer not to
233 * go all the way down to the bottom just to discover that.
235 * Why all these "- 1"s? Because 0 represents both the bottom
236 * of the address space and the top of it (using -1 for the
237 * top wouldn't help much: the masks would do the wrong thing).
238 * The rule is that addr 0 and floor 0 refer to the bottom of
239 * the address space, but end 0 and ceiling 0 refer to the top
240 * Comparisons need to use "end - 1" and "ceiling - 1" (though
241 * that end 0 case should be mythical).
243 * Wherever addr is brought up or ceiling brought down, we must
244 * be careful to reject "the opposite 0" before it confuses the
245 * subsequent tests. But what about where end is brought down
246 * by PMD_SIZE below? no, end can't go down to 0 there.
248 * Whereas we round start (addr) and ceiling down, by different
249 * masks at different levels, in order to test whether a table
250 * now has no other vmas using it, so can be freed, we don't
251 * bother to round floor or end up - the tests don't need that.
265 if (end
- 1 > ceiling
- 1)
271 pgd
= pgd_offset(tlb
->mm
, addr
);
273 next
= pgd_addr_end(addr
, end
);
274 if (pgd_none_or_clear_bad(pgd
))
276 free_pud_range(tlb
, pgd
, addr
, next
, floor
, ceiling
);
277 } while (pgd
++, addr
= next
, addr
!= end
);
280 void free_pgtables(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
281 unsigned long floor
, unsigned long ceiling
)
284 struct vm_area_struct
*next
= vma
->vm_next
;
285 unsigned long addr
= vma
->vm_start
;
288 * Hide vma from rmap and vmtruncate before freeing pgtables
290 anon_vma_unlink(vma
);
291 unlink_file_vma(vma
);
293 if (is_vm_hugetlb_page(vma
)) {
294 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
295 floor
, next
? next
->vm_start
: ceiling
);
298 * Optimization: gather nearby vmas into one call down
300 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
301 && !is_vm_hugetlb_page(next
)) {
304 anon_vma_unlink(vma
);
305 unlink_file_vma(vma
);
307 free_pgd_range(tlb
, addr
, vma
->vm_end
,
308 floor
, next
? next
->vm_start
: ceiling
);
314 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
316 pgtable_t
new = pte_alloc_one(mm
, address
);
321 * Ensure all pte setup (eg. pte page lock and page clearing) are
322 * visible before the pte is made visible to other CPUs by being
323 * put into page tables.
325 * The other side of the story is the pointer chasing in the page
326 * table walking code (when walking the page table without locking;
327 * ie. most of the time). Fortunately, these data accesses consist
328 * of a chain of data-dependent loads, meaning most CPUs (alpha
329 * being the notable exception) will already guarantee loads are
330 * seen in-order. See the alpha page table accessors for the
331 * smp_read_barrier_depends() barriers in page table walking code.
333 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
335 spin_lock(&mm
->page_table_lock
);
336 if (!pmd_present(*pmd
)) { /* Has another populated it ? */
338 pmd_populate(mm
, pmd
, new);
341 spin_unlock(&mm
->page_table_lock
);
347 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
349 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
353 smp_wmb(); /* See comment in __pte_alloc */
355 spin_lock(&init_mm
.page_table_lock
);
356 if (!pmd_present(*pmd
)) { /* Has another populated it ? */
357 pmd_populate_kernel(&init_mm
, pmd
, new);
360 spin_unlock(&init_mm
.page_table_lock
);
362 pte_free_kernel(&init_mm
, new);
366 static inline void add_mm_rss(struct mm_struct
*mm
, int file_rss
, int anon_rss
)
369 add_mm_counter(mm
, file_rss
, file_rss
);
371 add_mm_counter(mm
, anon_rss
, anon_rss
);
375 * This function is called to print an error when a bad pte
376 * is found. For example, we might have a PFN-mapped pte in
377 * a region that doesn't allow it.
379 * The calling function must still handle the error.
381 static void print_bad_pte(struct vm_area_struct
*vma
, unsigned long addr
,
382 pte_t pte
, struct page
*page
)
384 pgd_t
*pgd
= pgd_offset(vma
->vm_mm
, addr
);
385 pud_t
*pud
= pud_offset(pgd
, addr
);
386 pmd_t
*pmd
= pmd_offset(pud
, addr
);
387 struct address_space
*mapping
;
389 static unsigned long resume
;
390 static unsigned long nr_shown
;
391 static unsigned long nr_unshown
;
394 * Allow a burst of 60 reports, then keep quiet for that minute;
395 * or allow a steady drip of one report per second.
397 if (nr_shown
== 60) {
398 if (time_before(jiffies
, resume
)) {
404 "BUG: Bad page map: %lu messages suppressed\n",
411 resume
= jiffies
+ 60 * HZ
;
413 mapping
= vma
->vm_file
? vma
->vm_file
->f_mapping
: NULL
;
414 index
= linear_page_index(vma
, addr
);
417 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
419 (long long)pte_val(pte
), (long long)pmd_val(*pmd
));
422 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
423 page
, (void *)page
->flags
, page_count(page
),
424 page_mapcount(page
), page
->mapping
, page
->index
);
427 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
428 (void *)addr
, vma
->vm_flags
, vma
->anon_vma
, mapping
, index
);
430 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
433 print_symbol(KERN_ALERT
"vma->vm_ops->fault: %s\n",
434 (unsigned long)vma
->vm_ops
->fault
);
435 if (vma
->vm_file
&& vma
->vm_file
->f_op
)
436 print_symbol(KERN_ALERT
"vma->vm_file->f_op->mmap: %s\n",
437 (unsigned long)vma
->vm_file
->f_op
->mmap
);
439 add_taint(TAINT_BAD_PAGE
);
442 static inline int is_cow_mapping(unsigned int flags
)
444 return (flags
& (VM_SHARED
| VM_MAYWRITE
)) == VM_MAYWRITE
;
448 * vm_normal_page -- This function gets the "struct page" associated with a pte.
450 * "Special" mappings do not wish to be associated with a "struct page" (either
451 * it doesn't exist, or it exists but they don't want to touch it). In this
452 * case, NULL is returned here. "Normal" mappings do have a struct page.
454 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
455 * pte bit, in which case this function is trivial. Secondly, an architecture
456 * may not have a spare pte bit, which requires a more complicated scheme,
459 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
460 * special mapping (even if there are underlying and valid "struct pages").
461 * COWed pages of a VM_PFNMAP are always normal.
463 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
464 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
465 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
466 * mapping will always honor the rule
468 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
470 * And for normal mappings this is false.
472 * This restricts such mappings to be a linear translation from virtual address
473 * to pfn. To get around this restriction, we allow arbitrary mappings so long
474 * as the vma is not a COW mapping; in that case, we know that all ptes are
475 * special (because none can have been COWed).
478 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
480 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
481 * page" backing, however the difference is that _all_ pages with a struct
482 * page (that is, those where pfn_valid is true) are refcounted and considered
483 * normal pages by the VM. The disadvantage is that pages are refcounted
484 * (which can be slower and simply not an option for some PFNMAP users). The
485 * advantage is that we don't have to follow the strict linearity rule of
486 * PFNMAP mappings in order to support COWable mappings.
489 #ifdef __HAVE_ARCH_PTE_SPECIAL
490 # define HAVE_PTE_SPECIAL 1
492 # define HAVE_PTE_SPECIAL 0
494 struct page
*vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
,
497 unsigned long pfn
= pte_pfn(pte
);
499 if (HAVE_PTE_SPECIAL
) {
500 if (likely(!pte_special(pte
)))
502 if (!(vma
->vm_flags
& (VM_PFNMAP
| VM_MIXEDMAP
)))
503 print_bad_pte(vma
, addr
, pte
, NULL
);
507 /* !HAVE_PTE_SPECIAL case follows: */
509 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
510 if (vma
->vm_flags
& VM_MIXEDMAP
) {
516 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
517 if (pfn
== vma
->vm_pgoff
+ off
)
519 if (!is_cow_mapping(vma
->vm_flags
))
525 if (unlikely(pfn
> highest_memmap_pfn
)) {
526 print_bad_pte(vma
, addr
, pte
, NULL
);
531 * NOTE! We still have PageReserved() pages in the page tables.
532 * eg. VDSO mappings can cause them to exist.
535 return pfn_to_page(pfn
);
539 * copy one vm_area from one task to the other. Assumes the page tables
540 * already present in the new task to be cleared in the whole range
541 * covered by this vma.
545 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
546 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
547 unsigned long addr
, int *rss
)
549 unsigned long vm_flags
= vma
->vm_flags
;
550 pte_t pte
= *src_pte
;
553 /* pte contains position in swap or file, so copy. */
554 if (unlikely(!pte_present(pte
))) {
555 if (!pte_file(pte
)) {
556 swp_entry_t entry
= pte_to_swp_entry(pte
);
558 swap_duplicate(entry
);
559 /* make sure dst_mm is on swapoff's mmlist. */
560 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
561 spin_lock(&mmlist_lock
);
562 if (list_empty(&dst_mm
->mmlist
))
563 list_add(&dst_mm
->mmlist
,
565 spin_unlock(&mmlist_lock
);
567 if (is_write_migration_entry(entry
) &&
568 is_cow_mapping(vm_flags
)) {
570 * COW mappings require pages in both parent
571 * and child to be set to read.
573 make_migration_entry_read(&entry
);
574 pte
= swp_entry_to_pte(entry
);
575 set_pte_at(src_mm
, addr
, src_pte
, pte
);
582 * If it's a COW mapping, write protect it both
583 * in the parent and the child
585 if (is_cow_mapping(vm_flags
)) {
586 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
587 pte
= pte_wrprotect(pte
);
591 * If it's a shared mapping, mark it clean in
594 if (vm_flags
& VM_SHARED
)
595 pte
= pte_mkclean(pte
);
596 pte
= pte_mkold(pte
);
598 page
= vm_normal_page(vma
, addr
, pte
);
602 rss
[PageAnon(page
)]++;
606 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
609 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
610 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
611 unsigned long addr
, unsigned long end
)
613 pte_t
*src_pte
, *dst_pte
;
614 spinlock_t
*src_ptl
, *dst_ptl
;
620 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
623 src_pte
= pte_offset_map_nested(src_pmd
, addr
);
624 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
625 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
626 arch_enter_lazy_mmu_mode();
630 * We are holding two locks at this point - either of them
631 * could generate latencies in another task on another CPU.
633 if (progress
>= 32) {
635 if (need_resched() ||
636 spin_needbreak(src_ptl
) || spin_needbreak(dst_ptl
))
639 if (pte_none(*src_pte
)) {
643 copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
, vma
, addr
, rss
);
645 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
647 arch_leave_lazy_mmu_mode();
648 spin_unlock(src_ptl
);
649 pte_unmap_nested(src_pte
- 1);
650 add_mm_rss(dst_mm
, rss
[0], rss
[1]);
651 pte_unmap_unlock(dst_pte
- 1, dst_ptl
);
658 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
659 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
660 unsigned long addr
, unsigned long end
)
662 pmd_t
*src_pmd
, *dst_pmd
;
665 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
668 src_pmd
= pmd_offset(src_pud
, addr
);
670 next
= pmd_addr_end(addr
, end
);
671 if (pmd_none_or_clear_bad(src_pmd
))
673 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
676 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
680 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
681 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
682 unsigned long addr
, unsigned long end
)
684 pud_t
*src_pud
, *dst_pud
;
687 dst_pud
= pud_alloc(dst_mm
, dst_pgd
, addr
);
690 src_pud
= pud_offset(src_pgd
, addr
);
692 next
= pud_addr_end(addr
, end
);
693 if (pud_none_or_clear_bad(src_pud
))
695 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
698 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
702 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
703 struct vm_area_struct
*vma
)
705 pgd_t
*src_pgd
, *dst_pgd
;
707 unsigned long addr
= vma
->vm_start
;
708 unsigned long end
= vma
->vm_end
;
712 * Don't copy ptes where a page fault will fill them correctly.
713 * Fork becomes much lighter when there are big shared or private
714 * readonly mappings. The tradeoff is that copy_page_range is more
715 * efficient than faulting.
717 if (!(vma
->vm_flags
& (VM_HUGETLB
|VM_NONLINEAR
|VM_PFNMAP
|VM_INSERTPAGE
))) {
722 if (is_vm_hugetlb_page(vma
))
723 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
725 if (unlikely(is_pfn_mapping(vma
))) {
727 * We do not free on error cases below as remove_vma
728 * gets called on error from higher level routine
730 ret
= track_pfn_vma_copy(vma
);
736 * We need to invalidate the secondary MMU mappings only when
737 * there could be a permission downgrade on the ptes of the
738 * parent mm. And a permission downgrade will only happen if
739 * is_cow_mapping() returns true.
741 if (is_cow_mapping(vma
->vm_flags
))
742 mmu_notifier_invalidate_range_start(src_mm
, addr
, end
);
745 dst_pgd
= pgd_offset(dst_mm
, addr
);
746 src_pgd
= pgd_offset(src_mm
, addr
);
748 next
= pgd_addr_end(addr
, end
);
749 if (pgd_none_or_clear_bad(src_pgd
))
751 if (unlikely(copy_pud_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
756 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
758 if (is_cow_mapping(vma
->vm_flags
))
759 mmu_notifier_invalidate_range_end(src_mm
,
764 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
765 struct vm_area_struct
*vma
, pmd_t
*pmd
,
766 unsigned long addr
, unsigned long end
,
767 long *zap_work
, struct zap_details
*details
)
769 struct mm_struct
*mm
= tlb
->mm
;
775 pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
776 arch_enter_lazy_mmu_mode();
779 if (pte_none(ptent
)) {
784 (*zap_work
) -= PAGE_SIZE
;
786 if (pte_present(ptent
)) {
789 page
= vm_normal_page(vma
, addr
, ptent
);
790 if (unlikely(details
) && page
) {
792 * unmap_shared_mapping_pages() wants to
793 * invalidate cache without truncating:
794 * unmap shared but keep private pages.
796 if (details
->check_mapping
&&
797 details
->check_mapping
!= page
->mapping
)
800 * Each page->index must be checked when
801 * invalidating or truncating nonlinear.
803 if (details
->nonlinear_vma
&&
804 (page
->index
< details
->first_index
||
805 page
->index
> details
->last_index
))
808 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
810 tlb_remove_tlb_entry(tlb
, pte
, addr
);
813 if (unlikely(details
) && details
->nonlinear_vma
814 && linear_page_index(details
->nonlinear_vma
,
815 addr
) != page
->index
)
816 set_pte_at(mm
, addr
, pte
,
817 pgoff_to_pte(page
->index
));
821 if (pte_dirty(ptent
))
822 set_page_dirty(page
);
823 if (pte_young(ptent
) &&
824 likely(!VM_SequentialReadHint(vma
)))
825 mark_page_accessed(page
);
828 page_remove_rmap(page
);
829 if (unlikely(page_mapcount(page
) < 0))
830 print_bad_pte(vma
, addr
, ptent
, page
);
831 tlb_remove_page(tlb
, page
);
835 * If details->check_mapping, we leave swap entries;
836 * if details->nonlinear_vma, we leave file entries.
838 if (unlikely(details
))
840 if (pte_file(ptent
)) {
841 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
)))
842 print_bad_pte(vma
, addr
, ptent
, NULL
);
844 (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent
))))
845 print_bad_pte(vma
, addr
, ptent
, NULL
);
846 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
847 } while (pte
++, addr
+= PAGE_SIZE
, (addr
!= end
&& *zap_work
> 0));
849 add_mm_rss(mm
, file_rss
, anon_rss
);
850 arch_leave_lazy_mmu_mode();
851 pte_unmap_unlock(pte
- 1, ptl
);
856 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
857 struct vm_area_struct
*vma
, pud_t
*pud
,
858 unsigned long addr
, unsigned long end
,
859 long *zap_work
, struct zap_details
*details
)
864 pmd
= pmd_offset(pud
, addr
);
866 next
= pmd_addr_end(addr
, end
);
867 if (pmd_none_or_clear_bad(pmd
)) {
871 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
,
873 } while (pmd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
878 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
879 struct vm_area_struct
*vma
, pgd_t
*pgd
,
880 unsigned long addr
, unsigned long end
,
881 long *zap_work
, struct zap_details
*details
)
886 pud
= pud_offset(pgd
, addr
);
888 next
= pud_addr_end(addr
, end
);
889 if (pud_none_or_clear_bad(pud
)) {
893 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
,
895 } while (pud
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
900 static unsigned long unmap_page_range(struct mmu_gather
*tlb
,
901 struct vm_area_struct
*vma
,
902 unsigned long addr
, unsigned long end
,
903 long *zap_work
, struct zap_details
*details
)
908 if (details
&& !details
->check_mapping
&& !details
->nonlinear_vma
)
912 tlb_start_vma(tlb
, vma
);
913 pgd
= pgd_offset(vma
->vm_mm
, addr
);
915 next
= pgd_addr_end(addr
, end
);
916 if (pgd_none_or_clear_bad(pgd
)) {
920 next
= zap_pud_range(tlb
, vma
, pgd
, addr
, next
,
922 } while (pgd
++, addr
= next
, (addr
!= end
&& *zap_work
> 0));
923 tlb_end_vma(tlb
, vma
);
928 #ifdef CONFIG_PREEMPT
929 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
931 /* No preempt: go for improved straight-line efficiency */
932 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
936 * unmap_vmas - unmap a range of memory covered by a list of vma's
937 * @tlbp: address of the caller's struct mmu_gather
938 * @vma: the starting vma
939 * @start_addr: virtual address at which to start unmapping
940 * @end_addr: virtual address at which to end unmapping
941 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
942 * @details: details of nonlinear truncation or shared cache invalidation
944 * Returns the end address of the unmapping (restart addr if interrupted).
946 * Unmap all pages in the vma list.
948 * We aim to not hold locks for too long (for scheduling latency reasons).
949 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
950 * return the ending mmu_gather to the caller.
952 * Only addresses between `start' and `end' will be unmapped.
954 * The VMA list must be sorted in ascending virtual address order.
956 * unmap_vmas() assumes that the caller will flush the whole unmapped address
957 * range after unmap_vmas() returns. So the only responsibility here is to
958 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
959 * drops the lock and schedules.
961 unsigned long unmap_vmas(struct mmu_gather
**tlbp
,
962 struct vm_area_struct
*vma
, unsigned long start_addr
,
963 unsigned long end_addr
, unsigned long *nr_accounted
,
964 struct zap_details
*details
)
966 long zap_work
= ZAP_BLOCK_SIZE
;
967 unsigned long tlb_start
= 0; /* For tlb_finish_mmu */
968 int tlb_start_valid
= 0;
969 unsigned long start
= start_addr
;
970 spinlock_t
*i_mmap_lock
= details
? details
->i_mmap_lock
: NULL
;
971 int fullmm
= (*tlbp
)->fullmm
;
972 struct mm_struct
*mm
= vma
->vm_mm
;
974 mmu_notifier_invalidate_range_start(mm
, start_addr
, end_addr
);
975 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
) {
978 start
= max(vma
->vm_start
, start_addr
);
979 if (start
>= vma
->vm_end
)
981 end
= min(vma
->vm_end
, end_addr
);
982 if (end
<= vma
->vm_start
)
985 if (vma
->vm_flags
& VM_ACCOUNT
)
986 *nr_accounted
+= (end
- start
) >> PAGE_SHIFT
;
988 if (unlikely(is_pfn_mapping(vma
)))
989 untrack_pfn_vma(vma
, 0, 0);
991 while (start
!= end
) {
992 if (!tlb_start_valid
) {
997 if (unlikely(is_vm_hugetlb_page(vma
))) {
999 * It is undesirable to test vma->vm_file as it
1000 * should be non-null for valid hugetlb area.
1001 * However, vm_file will be NULL in the error
1002 * cleanup path of do_mmap_pgoff. When
1003 * hugetlbfs ->mmap method fails,
1004 * do_mmap_pgoff() nullifies vma->vm_file
1005 * before calling this function to clean up.
1006 * Since no pte has actually been setup, it is
1007 * safe to do nothing in this case.
1010 unmap_hugepage_range(vma
, start
, end
, NULL
);
1011 zap_work
-= (end
- start
) /
1012 pages_per_huge_page(hstate_vma(vma
));
1017 start
= unmap_page_range(*tlbp
, vma
,
1018 start
, end
, &zap_work
, details
);
1021 BUG_ON(start
!= end
);
1025 tlb_finish_mmu(*tlbp
, tlb_start
, start
);
1027 if (need_resched() ||
1028 (i_mmap_lock
&& spin_needbreak(i_mmap_lock
))) {
1036 *tlbp
= tlb_gather_mmu(vma
->vm_mm
, fullmm
);
1037 tlb_start_valid
= 0;
1038 zap_work
= ZAP_BLOCK_SIZE
;
1042 mmu_notifier_invalidate_range_end(mm
, start_addr
, end_addr
);
1043 return start
; /* which is now the end (or restart) address */
1047 * zap_page_range - remove user pages in a given range
1048 * @vma: vm_area_struct holding the applicable pages
1049 * @address: starting address of pages to zap
1050 * @size: number of bytes to zap
1051 * @details: details of nonlinear truncation or shared cache invalidation
1053 unsigned long zap_page_range(struct vm_area_struct
*vma
, unsigned long address
,
1054 unsigned long size
, struct zap_details
*details
)
1056 struct mm_struct
*mm
= vma
->vm_mm
;
1057 struct mmu_gather
*tlb
;
1058 unsigned long end
= address
+ size
;
1059 unsigned long nr_accounted
= 0;
1062 tlb
= tlb_gather_mmu(mm
, 0);
1063 update_hiwater_rss(mm
);
1064 end
= unmap_vmas(&tlb
, vma
, address
, end
, &nr_accounted
, details
);
1066 tlb_finish_mmu(tlb
, address
, end
);
1071 * zap_vma_ptes - remove ptes mapping the vma
1072 * @vma: vm_area_struct holding ptes to be zapped
1073 * @address: starting address of pages to zap
1074 * @size: number of bytes to zap
1076 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1078 * The entire address range must be fully contained within the vma.
1080 * Returns 0 if successful.
1082 int zap_vma_ptes(struct vm_area_struct
*vma
, unsigned long address
,
1085 if (address
< vma
->vm_start
|| address
+ size
> vma
->vm_end
||
1086 !(vma
->vm_flags
& VM_PFNMAP
))
1088 zap_page_range(vma
, address
, size
, NULL
);
1091 EXPORT_SYMBOL_GPL(zap_vma_ptes
);
1094 * Do a quick page-table lookup for a single page.
1096 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
1105 struct mm_struct
*mm
= vma
->vm_mm
;
1107 page
= follow_huge_addr(mm
, address
, flags
& FOLL_WRITE
);
1108 if (!IS_ERR(page
)) {
1109 BUG_ON(flags
& FOLL_GET
);
1114 pgd
= pgd_offset(mm
, address
);
1115 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
1118 pud
= pud_offset(pgd
, address
);
1121 if (pud_huge(*pud
)) {
1122 BUG_ON(flags
& FOLL_GET
);
1123 page
= follow_huge_pud(mm
, address
, pud
, flags
& FOLL_WRITE
);
1126 if (unlikely(pud_bad(*pud
)))
1129 pmd
= pmd_offset(pud
, address
);
1132 if (pmd_huge(*pmd
)) {
1133 BUG_ON(flags
& FOLL_GET
);
1134 page
= follow_huge_pmd(mm
, address
, pmd
, flags
& FOLL_WRITE
);
1137 if (unlikely(pmd_bad(*pmd
)))
1140 ptep
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
1143 if (!pte_present(pte
))
1145 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
1147 page
= vm_normal_page(vma
, address
, pte
);
1148 if (unlikely(!page
))
1151 if (flags
& FOLL_GET
)
1153 if (flags
& FOLL_TOUCH
) {
1154 if ((flags
& FOLL_WRITE
) &&
1155 !pte_dirty(pte
) && !PageDirty(page
))
1156 set_page_dirty(page
);
1158 * pte_mkyoung() would be more correct here, but atomic care
1159 * is needed to avoid losing the dirty bit: it is easier to use
1160 * mark_page_accessed().
1162 mark_page_accessed(page
);
1165 pte_unmap_unlock(ptep
, ptl
);
1170 pte_unmap_unlock(ptep
, ptl
);
1171 return ERR_PTR(-EFAULT
);
1174 pte_unmap_unlock(ptep
, ptl
);
1177 /* Fall through to ZERO_PAGE handling */
1180 * When core dumping an enormous anonymous area that nobody
1181 * has touched so far, we don't want to allocate page tables.
1183 if (flags
& FOLL_ANON
) {
1184 page
= ZERO_PAGE(0);
1185 if (flags
& FOLL_GET
)
1187 BUG_ON(flags
& FOLL_WRITE
);
1192 /* Can we do the FOLL_ANON optimization? */
1193 static inline int use_zero_page(struct vm_area_struct
*vma
)
1196 * We don't want to optimize FOLL_ANON for make_pages_present()
1197 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
1198 * we want to get the page from the page tables to make sure
1199 * that we serialize and update with any other user of that
1202 if (vma
->vm_flags
& (VM_LOCKED
| VM_SHARED
))
1205 * And if we have a fault routine, it's not an anonymous region.
1207 return !vma
->vm_ops
|| !vma
->vm_ops
->fault
;
1212 int __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1213 unsigned long start
, int nr_pages
, int flags
,
1214 struct page
**pages
, struct vm_area_struct
**vmas
)
1217 unsigned int vm_flags
= 0;
1218 int write
= !!(flags
& GUP_FLAGS_WRITE
);
1219 int force
= !!(flags
& GUP_FLAGS_FORCE
);
1220 int ignore
= !!(flags
& GUP_FLAGS_IGNORE_VMA_PERMISSIONS
);
1221 int ignore_sigkill
= !!(flags
& GUP_FLAGS_IGNORE_SIGKILL
);
1226 * Require read or write permissions.
1227 * If 'force' is set, we only require the "MAY" flags.
1229 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
1230 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
1234 struct vm_area_struct
*vma
;
1235 unsigned int foll_flags
;
1237 vma
= find_extend_vma(mm
, start
);
1238 if (!vma
&& in_gate_area(tsk
, start
)) {
1239 unsigned long pg
= start
& PAGE_MASK
;
1240 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1246 /* user gate pages are read-only */
1247 if (!ignore
&& write
)
1248 return i
? : -EFAULT
;
1250 pgd
= pgd_offset_k(pg
);
1252 pgd
= pgd_offset_gate(mm
, pg
);
1253 BUG_ON(pgd_none(*pgd
));
1254 pud
= pud_offset(pgd
, pg
);
1255 BUG_ON(pud_none(*pud
));
1256 pmd
= pmd_offset(pud
, pg
);
1258 return i
? : -EFAULT
;
1259 pte
= pte_offset_map(pmd
, pg
);
1260 if (pte_none(*pte
)) {
1262 return i
? : -EFAULT
;
1265 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1280 (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
1281 (!ignore
&& !(vm_flags
& vma
->vm_flags
)))
1282 return i
? : -EFAULT
;
1284 if (is_vm_hugetlb_page(vma
)) {
1285 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1286 &start
, &nr_pages
, i
, write
);
1290 foll_flags
= FOLL_TOUCH
;
1292 foll_flags
|= FOLL_GET
;
1293 if (!write
&& use_zero_page(vma
))
1294 foll_flags
|= FOLL_ANON
;
1300 * If we have a pending SIGKILL, don't keep faulting
1301 * pages and potentially allocating memory, unless
1302 * current is handling munlock--e.g., on exit. In
1303 * that case, we are not allocating memory. Rather,
1304 * we're only unlocking already resident/mapped pages.
1306 if (unlikely(!ignore_sigkill
&&
1307 fatal_signal_pending(current
)))
1308 return i
? i
: -ERESTARTSYS
;
1311 foll_flags
|= FOLL_WRITE
;
1314 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1317 ret
= handle_mm_fault(mm
, vma
, start
,
1318 (foll_flags
& FOLL_WRITE
) ?
1319 FAULT_FLAG_WRITE
: 0);
1321 if (ret
& VM_FAULT_ERROR
) {
1322 if (ret
& VM_FAULT_OOM
)
1323 return i
? i
: -ENOMEM
;
1324 else if (ret
& VM_FAULT_SIGBUS
)
1325 return i
? i
: -EFAULT
;
1328 if (ret
& VM_FAULT_MAJOR
)
1334 * The VM_FAULT_WRITE bit tells us that
1335 * do_wp_page has broken COW when necessary,
1336 * even if maybe_mkwrite decided not to set
1337 * pte_write. We can thus safely do subsequent
1338 * page lookups as if they were reads. But only
1339 * do so when looping for pte_write is futile:
1340 * in some cases userspace may also be wanting
1341 * to write to the gotten user page, which a
1342 * read fault here might prevent (a readonly
1343 * page might get reCOWed by userspace write).
1345 if ((ret
& VM_FAULT_WRITE
) &&
1346 !(vma
->vm_flags
& VM_WRITE
))
1347 foll_flags
&= ~FOLL_WRITE
;
1352 return i
? i
: PTR_ERR(page
);
1356 flush_anon_page(vma
, page
, start
);
1357 flush_dcache_page(page
);
1364 } while (nr_pages
&& start
< vma
->vm_end
);
1370 * get_user_pages() - pin user pages in memory
1371 * @tsk: task_struct of target task
1372 * @mm: mm_struct of target mm
1373 * @start: starting user address
1374 * @nr_pages: number of pages from start to pin
1375 * @write: whether pages will be written to by the caller
1376 * @force: whether to force write access even if user mapping is
1377 * readonly. This will result in the page being COWed even
1378 * in MAP_SHARED mappings. You do not want this.
1379 * @pages: array that receives pointers to the pages pinned.
1380 * Should be at least nr_pages long. Or NULL, if caller
1381 * only intends to ensure the pages are faulted in.
1382 * @vmas: array of pointers to vmas corresponding to each page.
1383 * Or NULL if the caller does not require them.
1385 * Returns number of pages pinned. This may be fewer than the number
1386 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1387 * were pinned, returns -errno. Each page returned must be released
1388 * with a put_page() call when it is finished with. vmas will only
1389 * remain valid while mmap_sem is held.
1391 * Must be called with mmap_sem held for read or write.
1393 * get_user_pages walks a process's page tables and takes a reference to
1394 * each struct page that each user address corresponds to at a given
1395 * instant. That is, it takes the page that would be accessed if a user
1396 * thread accesses the given user virtual address at that instant.
1398 * This does not guarantee that the page exists in the user mappings when
1399 * get_user_pages returns, and there may even be a completely different
1400 * page there in some cases (eg. if mmapped pagecache has been invalidated
1401 * and subsequently re faulted). However it does guarantee that the page
1402 * won't be freed completely. And mostly callers simply care that the page
1403 * contains data that was valid *at some point in time*. Typically, an IO
1404 * or similar operation cannot guarantee anything stronger anyway because
1405 * locks can't be held over the syscall boundary.
1407 * If write=0, the page must not be written to. If the page is written to,
1408 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1409 * after the page is finished with, and before put_page is called.
1411 * get_user_pages is typically used for fewer-copy IO operations, to get a
1412 * handle on the memory by some means other than accesses via the user virtual
1413 * addresses. The pages may be submitted for DMA to devices or accessed via
1414 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1415 * use the correct cache flushing APIs.
1417 * See also get_user_pages_fast, for performance critical applications.
1419 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1420 unsigned long start
, int nr_pages
, int write
, int force
,
1421 struct page
**pages
, struct vm_area_struct
**vmas
)
1426 flags
|= GUP_FLAGS_WRITE
;
1428 flags
|= GUP_FLAGS_FORCE
;
1430 return __get_user_pages(tsk
, mm
, start
, nr_pages
, flags
, pages
, vmas
);
1433 EXPORT_SYMBOL(get_user_pages
);
1435 pte_t
*get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
1438 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1439 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1441 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1443 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1449 * This is the old fallback for page remapping.
1451 * For historical reasons, it only allows reserved pages. Only
1452 * old drivers should use this, and they needed to mark their
1453 * pages reserved for the old functions anyway.
1455 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1456 struct page
*page
, pgprot_t prot
)
1458 struct mm_struct
*mm
= vma
->vm_mm
;
1467 flush_dcache_page(page
);
1468 pte
= get_locked_pte(mm
, addr
, &ptl
);
1472 if (!pte_none(*pte
))
1475 /* Ok, finally just insert the thing.. */
1477 inc_mm_counter(mm
, file_rss
);
1478 page_add_file_rmap(page
);
1479 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1482 pte_unmap_unlock(pte
, ptl
);
1485 pte_unmap_unlock(pte
, ptl
);
1491 * vm_insert_page - insert single page into user vma
1492 * @vma: user vma to map to
1493 * @addr: target user address of this page
1494 * @page: source kernel page
1496 * This allows drivers to insert individual pages they've allocated
1499 * The page has to be a nice clean _individual_ kernel allocation.
1500 * If you allocate a compound page, you need to have marked it as
1501 * such (__GFP_COMP), or manually just split the page up yourself
1502 * (see split_page()).
1504 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1505 * took an arbitrary page protection parameter. This doesn't allow
1506 * that. Your vma protection will have to be set up correctly, which
1507 * means that if you want a shared writable mapping, you'd better
1508 * ask for a shared writable mapping!
1510 * The page does not need to be reserved.
1512 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1515 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1517 if (!page_count(page
))
1519 vma
->vm_flags
|= VM_INSERTPAGE
;
1520 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1522 EXPORT_SYMBOL(vm_insert_page
);
1524 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1525 unsigned long pfn
, pgprot_t prot
)
1527 struct mm_struct
*mm
= vma
->vm_mm
;
1533 pte
= get_locked_pte(mm
, addr
, &ptl
);
1537 if (!pte_none(*pte
))
1540 /* Ok, finally just insert the thing.. */
1541 entry
= pte_mkspecial(pfn_pte(pfn
, prot
));
1542 set_pte_at(mm
, addr
, pte
, entry
);
1543 update_mmu_cache(vma
, addr
, entry
); /* XXX: why not for insert_page? */
1547 pte_unmap_unlock(pte
, ptl
);
1553 * vm_insert_pfn - insert single pfn into user vma
1554 * @vma: user vma to map to
1555 * @addr: target user address of this page
1556 * @pfn: source kernel pfn
1558 * Similar to vm_inert_page, this allows drivers to insert individual pages
1559 * they've allocated into a user vma. Same comments apply.
1561 * This function should only be called from a vm_ops->fault handler, and
1562 * in that case the handler should return NULL.
1564 * vma cannot be a COW mapping.
1566 * As this is called only for pages that do not currently exist, we
1567 * do not need to flush old virtual caches or the TLB.
1569 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1573 pgprot_t pgprot
= vma
->vm_page_prot
;
1575 * Technically, architectures with pte_special can avoid all these
1576 * restrictions (same for remap_pfn_range). However we would like
1577 * consistency in testing and feature parity among all, so we should
1578 * try to keep these invariants in place for everybody.
1580 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
1581 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
1582 (VM_PFNMAP
|VM_MIXEDMAP
));
1583 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
1584 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
1586 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1588 if (track_pfn_vma_new(vma
, &pgprot
, pfn
, PAGE_SIZE
))
1591 ret
= insert_pfn(vma
, addr
, pfn
, pgprot
);
1594 untrack_pfn_vma(vma
, pfn
, PAGE_SIZE
);
1598 EXPORT_SYMBOL(vm_insert_pfn
);
1600 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1603 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
1605 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1609 * If we don't have pte special, then we have to use the pfn_valid()
1610 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1611 * refcount the page if pfn_valid is true (hence insert_page rather
1614 if (!HAVE_PTE_SPECIAL
&& pfn_valid(pfn
)) {
1617 page
= pfn_to_page(pfn
);
1618 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1620 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
1622 EXPORT_SYMBOL(vm_insert_mixed
);
1625 * maps a range of physical memory into the requested pages. the old
1626 * mappings are removed. any references to nonexistent pages results
1627 * in null mappings (currently treated as "copy-on-access")
1629 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1630 unsigned long addr
, unsigned long end
,
1631 unsigned long pfn
, pgprot_t prot
)
1636 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1639 arch_enter_lazy_mmu_mode();
1641 BUG_ON(!pte_none(*pte
));
1642 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
1644 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1645 arch_leave_lazy_mmu_mode();
1646 pte_unmap_unlock(pte
- 1, ptl
);
1650 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1651 unsigned long addr
, unsigned long end
,
1652 unsigned long pfn
, pgprot_t prot
)
1657 pfn
-= addr
>> PAGE_SHIFT
;
1658 pmd
= pmd_alloc(mm
, pud
, addr
);
1662 next
= pmd_addr_end(addr
, end
);
1663 if (remap_pte_range(mm
, pmd
, addr
, next
,
1664 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1666 } while (pmd
++, addr
= next
, addr
!= end
);
1670 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1671 unsigned long addr
, unsigned long end
,
1672 unsigned long pfn
, pgprot_t prot
)
1677 pfn
-= addr
>> PAGE_SHIFT
;
1678 pud
= pud_alloc(mm
, pgd
, addr
);
1682 next
= pud_addr_end(addr
, end
);
1683 if (remap_pmd_range(mm
, pud
, addr
, next
,
1684 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1686 } while (pud
++, addr
= next
, addr
!= end
);
1691 * remap_pfn_range - remap kernel memory to userspace
1692 * @vma: user vma to map to
1693 * @addr: target user address to start at
1694 * @pfn: physical address of kernel memory
1695 * @size: size of map area
1696 * @prot: page protection flags for this mapping
1698 * Note: this is only safe if the mm semaphore is held when called.
1700 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1701 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1705 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1706 struct mm_struct
*mm
= vma
->vm_mm
;
1710 * Physically remapped pages are special. Tell the
1711 * rest of the world about it:
1712 * VM_IO tells people not to look at these pages
1713 * (accesses can have side effects).
1714 * VM_RESERVED is specified all over the place, because
1715 * in 2.4 it kept swapout's vma scan off this vma; but
1716 * in 2.6 the LRU scan won't even find its pages, so this
1717 * flag means no more than count its pages in reserved_vm,
1718 * and omit it from core dump, even when VM_IO turned off.
1719 * VM_PFNMAP tells the core MM that the base pages are just
1720 * raw PFN mappings, and do not have a "struct page" associated
1723 * There's a horrible special case to handle copy-on-write
1724 * behaviour that some programs depend on. We mark the "original"
1725 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1727 if (addr
== vma
->vm_start
&& end
== vma
->vm_end
) {
1728 vma
->vm_pgoff
= pfn
;
1729 vma
->vm_flags
|= VM_PFN_AT_MMAP
;
1730 } else if (is_cow_mapping(vma
->vm_flags
))
1733 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1735 err
= track_pfn_vma_new(vma
, &prot
, pfn
, PAGE_ALIGN(size
));
1738 * To indicate that track_pfn related cleanup is not
1739 * needed from higher level routine calling unmap_vmas
1741 vma
->vm_flags
&= ~(VM_IO
| VM_RESERVED
| VM_PFNMAP
);
1742 vma
->vm_flags
&= ~VM_PFN_AT_MMAP
;
1746 BUG_ON(addr
>= end
);
1747 pfn
-= addr
>> PAGE_SHIFT
;
1748 pgd
= pgd_offset(mm
, addr
);
1749 flush_cache_range(vma
, addr
, end
);
1751 next
= pgd_addr_end(addr
, end
);
1752 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1753 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1756 } while (pgd
++, addr
= next
, addr
!= end
);
1759 untrack_pfn_vma(vma
, pfn
, PAGE_ALIGN(size
));
1763 EXPORT_SYMBOL(remap_pfn_range
);
1765 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1766 unsigned long addr
, unsigned long end
,
1767 pte_fn_t fn
, void *data
)
1772 spinlock_t
*uninitialized_var(ptl
);
1774 pte
= (mm
== &init_mm
) ?
1775 pte_alloc_kernel(pmd
, addr
) :
1776 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1780 BUG_ON(pmd_huge(*pmd
));
1782 arch_enter_lazy_mmu_mode();
1784 token
= pmd_pgtable(*pmd
);
1787 err
= fn(pte
, token
, addr
, data
);
1790 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1792 arch_leave_lazy_mmu_mode();
1795 pte_unmap_unlock(pte
-1, ptl
);
1799 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1800 unsigned long addr
, unsigned long end
,
1801 pte_fn_t fn
, void *data
)
1807 BUG_ON(pud_huge(*pud
));
1809 pmd
= pmd_alloc(mm
, pud
, addr
);
1813 next
= pmd_addr_end(addr
, end
);
1814 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1817 } while (pmd
++, addr
= next
, addr
!= end
);
1821 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1822 unsigned long addr
, unsigned long end
,
1823 pte_fn_t fn
, void *data
)
1829 pud
= pud_alloc(mm
, pgd
, addr
);
1833 next
= pud_addr_end(addr
, end
);
1834 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1837 } while (pud
++, addr
= next
, addr
!= end
);
1842 * Scan a region of virtual memory, filling in page tables as necessary
1843 * and calling a provided function on each leaf page table.
1845 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1846 unsigned long size
, pte_fn_t fn
, void *data
)
1850 unsigned long start
= addr
, end
= addr
+ size
;
1853 BUG_ON(addr
>= end
);
1854 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1855 pgd
= pgd_offset(mm
, addr
);
1857 next
= pgd_addr_end(addr
, end
);
1858 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1861 } while (pgd
++, addr
= next
, addr
!= end
);
1862 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1865 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1868 * handle_pte_fault chooses page fault handler according to an entry
1869 * which was read non-atomically. Before making any commitment, on
1870 * those architectures or configurations (e.g. i386 with PAE) which
1871 * might give a mix of unmatched parts, do_swap_page and do_file_page
1872 * must check under lock before unmapping the pte and proceeding
1873 * (but do_wp_page is only called after already making such a check;
1874 * and do_anonymous_page and do_no_page can safely check later on).
1876 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1877 pte_t
*page_table
, pte_t orig_pte
)
1880 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1881 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1882 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1884 same
= pte_same(*page_table
, orig_pte
);
1888 pte_unmap(page_table
);
1893 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1894 * servicing faults for write access. In the normal case, do always want
1895 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1896 * that do not have writing enabled, when used by access_process_vm.
1898 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1900 if (likely(vma
->vm_flags
& VM_WRITE
))
1901 pte
= pte_mkwrite(pte
);
1905 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1908 * If the source page was a PFN mapping, we don't have
1909 * a "struct page" for it. We do a best-effort copy by
1910 * just copying from the original user address. If that
1911 * fails, we just zero-fill it. Live with it.
1913 if (unlikely(!src
)) {
1914 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1915 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1918 * This really shouldn't fail, because the page is there
1919 * in the page tables. But it might just be unreadable,
1920 * in which case we just give up and fill the result with
1923 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1924 memset(kaddr
, 0, PAGE_SIZE
);
1925 kunmap_atomic(kaddr
, KM_USER0
);
1926 flush_dcache_page(dst
);
1928 copy_user_highpage(dst
, src
, va
, vma
);
1932 * This routine handles present pages, when users try to write
1933 * to a shared page. It is done by copying the page to a new address
1934 * and decrementing the shared-page counter for the old page.
1936 * Note that this routine assumes that the protection checks have been
1937 * done by the caller (the low-level page fault routine in most cases).
1938 * Thus we can safely just mark it writable once we've done any necessary
1941 * We also mark the page dirty at this point even though the page will
1942 * change only once the write actually happens. This avoids a few races,
1943 * and potentially makes it more efficient.
1945 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1946 * but allow concurrent faults), with pte both mapped and locked.
1947 * We return with mmap_sem still held, but pte unmapped and unlocked.
1949 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1950 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1951 spinlock_t
*ptl
, pte_t orig_pte
)
1953 struct page
*old_page
, *new_page
;
1955 int reuse
= 0, ret
= 0;
1956 int page_mkwrite
= 0;
1957 struct page
*dirty_page
= NULL
;
1959 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1962 * VM_MIXEDMAP !pfn_valid() case
1964 * We should not cow pages in a shared writeable mapping.
1965 * Just mark the pages writable as we can't do any dirty
1966 * accounting on raw pfn maps.
1968 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1969 (VM_WRITE
|VM_SHARED
))
1975 * Take out anonymous pages first, anonymous shared vmas are
1976 * not dirty accountable.
1978 if (PageAnon(old_page
) && !PageKsm(old_page
)) {
1979 if (!trylock_page(old_page
)) {
1980 page_cache_get(old_page
);
1981 pte_unmap_unlock(page_table
, ptl
);
1982 lock_page(old_page
);
1983 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1985 if (!pte_same(*page_table
, orig_pte
)) {
1986 unlock_page(old_page
);
1987 page_cache_release(old_page
);
1990 page_cache_release(old_page
);
1992 reuse
= reuse_swap_page(old_page
);
1993 unlock_page(old_page
);
1994 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1995 (VM_WRITE
|VM_SHARED
))) {
1997 * Only catch write-faults on shared writable pages,
1998 * read-only shared pages can get COWed by
1999 * get_user_pages(.write=1, .force=1).
2001 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
2002 struct vm_fault vmf
;
2005 vmf
.virtual_address
= (void __user
*)(address
&
2007 vmf
.pgoff
= old_page
->index
;
2008 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2009 vmf
.page
= old_page
;
2012 * Notify the address space that the page is about to
2013 * become writable so that it can prohibit this or wait
2014 * for the page to get into an appropriate state.
2016 * We do this without the lock held, so that it can
2017 * sleep if it needs to.
2019 page_cache_get(old_page
);
2020 pte_unmap_unlock(page_table
, ptl
);
2022 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2024 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2026 goto unwritable_page
;
2028 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2029 lock_page(old_page
);
2030 if (!old_page
->mapping
) {
2031 ret
= 0; /* retry the fault */
2032 unlock_page(old_page
);
2033 goto unwritable_page
;
2036 VM_BUG_ON(!PageLocked(old_page
));
2039 * Since we dropped the lock we need to revalidate
2040 * the PTE as someone else may have changed it. If
2041 * they did, we just return, as we can count on the
2042 * MMU to tell us if they didn't also make it writable.
2044 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
2046 if (!pte_same(*page_table
, orig_pte
)) {
2047 unlock_page(old_page
);
2048 page_cache_release(old_page
);
2054 dirty_page
= old_page
;
2055 get_page(dirty_page
);
2061 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2062 entry
= pte_mkyoung(orig_pte
);
2063 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2064 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1))
2065 update_mmu_cache(vma
, address
, entry
);
2066 ret
|= VM_FAULT_WRITE
;
2071 * Ok, we need to copy. Oh, well..
2073 page_cache_get(old_page
);
2075 pte_unmap_unlock(page_table
, ptl
);
2077 if (unlikely(anon_vma_prepare(vma
)))
2079 VM_BUG_ON(old_page
== ZERO_PAGE(0));
2080 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
2084 * Don't let another task, with possibly unlocked vma,
2085 * keep the mlocked page.
2087 if ((vma
->vm_flags
& VM_LOCKED
) && old_page
) {
2088 lock_page(old_page
); /* for LRU manipulation */
2089 clear_page_mlock(old_page
);
2090 unlock_page(old_page
);
2092 cow_user_page(new_page
, old_page
, address
, vma
);
2093 __SetPageUptodate(new_page
);
2095 if (mem_cgroup_newpage_charge(new_page
, mm
, GFP_KERNEL
))
2099 * Re-check the pte - we dropped the lock
2101 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2102 if (likely(pte_same(*page_table
, orig_pte
))) {
2104 if (!PageAnon(old_page
)) {
2105 dec_mm_counter(mm
, file_rss
);
2106 inc_mm_counter(mm
, anon_rss
);
2109 inc_mm_counter(mm
, anon_rss
);
2110 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2111 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2112 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2114 * Clear the pte entry and flush it first, before updating the
2115 * pte with the new entry. This will avoid a race condition
2116 * seen in the presence of one thread doing SMC and another
2119 ptep_clear_flush(vma
, address
, page_table
);
2120 page_add_new_anon_rmap(new_page
, vma
, address
);
2122 * We call the notify macro here because, when using secondary
2123 * mmu page tables (such as kvm shadow page tables), we want the
2124 * new page to be mapped directly into the secondary page table.
2126 set_pte_at_notify(mm
, address
, page_table
, entry
);
2127 update_mmu_cache(vma
, address
, entry
);
2130 * Only after switching the pte to the new page may
2131 * we remove the mapcount here. Otherwise another
2132 * process may come and find the rmap count decremented
2133 * before the pte is switched to the new page, and
2134 * "reuse" the old page writing into it while our pte
2135 * here still points into it and can be read by other
2138 * The critical issue is to order this
2139 * page_remove_rmap with the ptp_clear_flush above.
2140 * Those stores are ordered by (if nothing else,)
2141 * the barrier present in the atomic_add_negative
2142 * in page_remove_rmap.
2144 * Then the TLB flush in ptep_clear_flush ensures that
2145 * no process can access the old page before the
2146 * decremented mapcount is visible. And the old page
2147 * cannot be reused until after the decremented
2148 * mapcount is visible. So transitively, TLBs to
2149 * old page will be flushed before it can be reused.
2151 page_remove_rmap(old_page
);
2154 /* Free the old page.. */
2155 new_page
= old_page
;
2156 ret
|= VM_FAULT_WRITE
;
2158 mem_cgroup_uncharge_page(new_page
);
2161 page_cache_release(new_page
);
2163 page_cache_release(old_page
);
2165 pte_unmap_unlock(page_table
, ptl
);
2168 * Yes, Virginia, this is actually required to prevent a race
2169 * with clear_page_dirty_for_io() from clearing the page dirty
2170 * bit after it clear all dirty ptes, but before a racing
2171 * do_wp_page installs a dirty pte.
2173 * do_no_page is protected similarly.
2175 if (!page_mkwrite
) {
2176 wait_on_page_locked(dirty_page
);
2177 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2179 put_page(dirty_page
);
2181 struct address_space
*mapping
= dirty_page
->mapping
;
2183 set_page_dirty(dirty_page
);
2184 unlock_page(dirty_page
);
2185 page_cache_release(dirty_page
);
2188 * Some device drivers do not set page.mapping
2189 * but still dirty their pages
2191 balance_dirty_pages_ratelimited(mapping
);
2195 /* file_update_time outside page_lock */
2197 file_update_time(vma
->vm_file
);
2201 page_cache_release(new_page
);
2205 unlock_page(old_page
);
2206 page_cache_release(old_page
);
2208 page_cache_release(old_page
);
2210 return VM_FAULT_OOM
;
2213 page_cache_release(old_page
);
2218 * Helper functions for unmap_mapping_range().
2220 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2222 * We have to restart searching the prio_tree whenever we drop the lock,
2223 * since the iterator is only valid while the lock is held, and anyway
2224 * a later vma might be split and reinserted earlier while lock dropped.
2226 * The list of nonlinear vmas could be handled more efficiently, using
2227 * a placeholder, but handle it in the same way until a need is shown.
2228 * It is important to search the prio_tree before nonlinear list: a vma
2229 * may become nonlinear and be shifted from prio_tree to nonlinear list
2230 * while the lock is dropped; but never shifted from list to prio_tree.
2232 * In order to make forward progress despite restarting the search,
2233 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2234 * quickly skip it next time around. Since the prio_tree search only
2235 * shows us those vmas affected by unmapping the range in question, we
2236 * can't efficiently keep all vmas in step with mapping->truncate_count:
2237 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2238 * mapping->truncate_count and vma->vm_truncate_count are protected by
2241 * In order to make forward progress despite repeatedly restarting some
2242 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2243 * and restart from that address when we reach that vma again. It might
2244 * have been split or merged, shrunk or extended, but never shifted: so
2245 * restart_addr remains valid so long as it remains in the vma's range.
2246 * unmap_mapping_range forces truncate_count to leap over page-aligned
2247 * values so we can save vma's restart_addr in its truncate_count field.
2249 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2251 static void reset_vma_truncate_counts(struct address_space
*mapping
)
2253 struct vm_area_struct
*vma
;
2254 struct prio_tree_iter iter
;
2256 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
2257 vma
->vm_truncate_count
= 0;
2258 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
2259 vma
->vm_truncate_count
= 0;
2262 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2263 unsigned long start_addr
, unsigned long end_addr
,
2264 struct zap_details
*details
)
2266 unsigned long restart_addr
;
2270 * files that support invalidating or truncating portions of the
2271 * file from under mmaped areas must have their ->fault function
2272 * return a locked page (and set VM_FAULT_LOCKED in the return).
2273 * This provides synchronisation against concurrent unmapping here.
2277 restart_addr
= vma
->vm_truncate_count
;
2278 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
2279 start_addr
= restart_addr
;
2280 if (start_addr
>= end_addr
) {
2281 /* Top of vma has been split off since last time */
2282 vma
->vm_truncate_count
= details
->truncate_count
;
2287 restart_addr
= zap_page_range(vma
, start_addr
,
2288 end_addr
- start_addr
, details
);
2289 need_break
= need_resched() || spin_needbreak(details
->i_mmap_lock
);
2291 if (restart_addr
>= end_addr
) {
2292 /* We have now completed this vma: mark it so */
2293 vma
->vm_truncate_count
= details
->truncate_count
;
2297 /* Note restart_addr in vma's truncate_count field */
2298 vma
->vm_truncate_count
= restart_addr
;
2303 spin_unlock(details
->i_mmap_lock
);
2305 spin_lock(details
->i_mmap_lock
);
2309 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
2310 struct zap_details
*details
)
2312 struct vm_area_struct
*vma
;
2313 struct prio_tree_iter iter
;
2314 pgoff_t vba
, vea
, zba
, zea
;
2317 vma_prio_tree_foreach(vma
, &iter
, root
,
2318 details
->first_index
, details
->last_index
) {
2319 /* Skip quickly over those we have already dealt with */
2320 if (vma
->vm_truncate_count
== details
->truncate_count
)
2323 vba
= vma
->vm_pgoff
;
2324 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
2325 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2326 zba
= details
->first_index
;
2329 zea
= details
->last_index
;
2333 if (unmap_mapping_range_vma(vma
,
2334 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2335 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2341 static inline void unmap_mapping_range_list(struct list_head
*head
,
2342 struct zap_details
*details
)
2344 struct vm_area_struct
*vma
;
2347 * In nonlinear VMAs there is no correspondence between virtual address
2348 * offset and file offset. So we must perform an exhaustive search
2349 * across *all* the pages in each nonlinear VMA, not just the pages
2350 * whose virtual address lies outside the file truncation point.
2353 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
2354 /* Skip quickly over those we have already dealt with */
2355 if (vma
->vm_truncate_count
== details
->truncate_count
)
2357 details
->nonlinear_vma
= vma
;
2358 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
2359 vma
->vm_end
, details
) < 0)
2365 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2366 * @mapping: the address space containing mmaps to be unmapped.
2367 * @holebegin: byte in first page to unmap, relative to the start of
2368 * the underlying file. This will be rounded down to a PAGE_SIZE
2369 * boundary. Note that this is different from vmtruncate(), which
2370 * must keep the partial page. In contrast, we must get rid of
2372 * @holelen: size of prospective hole in bytes. This will be rounded
2373 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2375 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2376 * but 0 when invalidating pagecache, don't throw away private data.
2378 void unmap_mapping_range(struct address_space
*mapping
,
2379 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2381 struct zap_details details
;
2382 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2383 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2385 /* Check for overflow. */
2386 if (sizeof(holelen
) > sizeof(hlen
)) {
2388 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2389 if (holeend
& ~(long long)ULONG_MAX
)
2390 hlen
= ULONG_MAX
- hba
+ 1;
2393 details
.check_mapping
= even_cows
? NULL
: mapping
;
2394 details
.nonlinear_vma
= NULL
;
2395 details
.first_index
= hba
;
2396 details
.last_index
= hba
+ hlen
- 1;
2397 if (details
.last_index
< details
.first_index
)
2398 details
.last_index
= ULONG_MAX
;
2399 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
2401 spin_lock(&mapping
->i_mmap_lock
);
2403 /* Protect against endless unmapping loops */
2404 mapping
->truncate_count
++;
2405 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
2406 if (mapping
->truncate_count
== 0)
2407 reset_vma_truncate_counts(mapping
);
2408 mapping
->truncate_count
++;
2410 details
.truncate_count
= mapping
->truncate_count
;
2412 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
2413 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2414 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
2415 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
2416 spin_unlock(&mapping
->i_mmap_lock
);
2418 EXPORT_SYMBOL(unmap_mapping_range
);
2421 * vmtruncate - unmap mappings "freed" by truncate() syscall
2422 * @inode: inode of the file used
2423 * @offset: file offset to start truncating
2425 * NOTE! We have to be ready to update the memory sharing
2426 * between the file and the memory map for a potential last
2427 * incomplete page. Ugly, but necessary.
2429 int vmtruncate(struct inode
* inode
, loff_t offset
)
2431 if (inode
->i_size
< offset
) {
2432 unsigned long limit
;
2434 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
2435 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
2437 if (offset
> inode
->i_sb
->s_maxbytes
)
2439 i_size_write(inode
, offset
);
2441 struct address_space
*mapping
= inode
->i_mapping
;
2444 * truncation of in-use swapfiles is disallowed - it would
2445 * cause subsequent swapout to scribble on the now-freed
2448 if (IS_SWAPFILE(inode
))
2450 i_size_write(inode
, offset
);
2453 * unmap_mapping_range is called twice, first simply for
2454 * efficiency so that truncate_inode_pages does fewer
2455 * single-page unmaps. However after this first call, and
2456 * before truncate_inode_pages finishes, it is possible for
2457 * private pages to be COWed, which remain after
2458 * truncate_inode_pages finishes, hence the second
2459 * unmap_mapping_range call must be made for correctness.
2461 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2462 truncate_inode_pages(mapping
, offset
);
2463 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2466 if (inode
->i_op
->truncate
)
2467 inode
->i_op
->truncate(inode
);
2471 send_sig(SIGXFSZ
, current
, 0);
2475 EXPORT_SYMBOL(vmtruncate
);
2477 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
2479 struct address_space
*mapping
= inode
->i_mapping
;
2482 * If the underlying filesystem is not going to provide
2483 * a way to truncate a range of blocks (punch a hole) -
2484 * we should return failure right now.
2486 if (!inode
->i_op
->truncate_range
)
2489 mutex_lock(&inode
->i_mutex
);
2490 down_write(&inode
->i_alloc_sem
);
2491 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2492 truncate_inode_pages_range(mapping
, offset
, end
);
2493 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2494 inode
->i_op
->truncate_range(inode
, offset
, end
);
2495 up_write(&inode
->i_alloc_sem
);
2496 mutex_unlock(&inode
->i_mutex
);
2502 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2503 * but allow concurrent faults), and pte mapped but not yet locked.
2504 * We return with mmap_sem still held, but pte unmapped and unlocked.
2506 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2507 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2508 unsigned int flags
, pte_t orig_pte
)
2514 struct mem_cgroup
*ptr
= NULL
;
2517 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2520 entry
= pte_to_swp_entry(orig_pte
);
2521 if (is_migration_entry(entry
)) {
2522 migration_entry_wait(mm
, pmd
, address
);
2525 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2526 page
= lookup_swap_cache(entry
);
2528 grab_swap_token(mm
); /* Contend for token _before_ read-in */
2529 page
= swapin_readahead(entry
,
2530 GFP_HIGHUSER_MOVABLE
, vma
, address
);
2533 * Back out if somebody else faulted in this pte
2534 * while we released the pte lock.
2536 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2537 if (likely(pte_same(*page_table
, orig_pte
)))
2539 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2543 /* Had to read the page from swap area: Major fault */
2544 ret
= VM_FAULT_MAJOR
;
2545 count_vm_event(PGMAJFAULT
);
2549 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2551 if (mem_cgroup_try_charge_swapin(mm
, page
, GFP_KERNEL
, &ptr
)) {
2557 * Back out if somebody else already faulted in this pte.
2559 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2560 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2563 if (unlikely(!PageUptodate(page
))) {
2564 ret
= VM_FAULT_SIGBUS
;
2569 * The page isn't present yet, go ahead with the fault.
2571 * Be careful about the sequence of operations here.
2572 * To get its accounting right, reuse_swap_page() must be called
2573 * while the page is counted on swap but not yet in mapcount i.e.
2574 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2575 * must be called after the swap_free(), or it will never succeed.
2576 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2577 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2578 * in page->private. In this case, a record in swap_cgroup is silently
2579 * discarded at swap_free().
2582 inc_mm_counter(mm
, anon_rss
);
2583 pte
= mk_pte(page
, vma
->vm_page_prot
);
2584 if ((flags
& FAULT_FLAG_WRITE
) && reuse_swap_page(page
)) {
2585 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2586 flags
&= ~FAULT_FLAG_WRITE
;
2588 flush_icache_page(vma
, page
);
2589 set_pte_at(mm
, address
, page_table
, pte
);
2590 page_add_anon_rmap(page
, vma
, address
);
2591 /* It's better to call commit-charge after rmap is established */
2592 mem_cgroup_commit_charge_swapin(page
, ptr
);
2595 if (vm_swap_full() || (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
2596 try_to_free_swap(page
);
2599 if (flags
& FAULT_FLAG_WRITE
) {
2600 ret
|= do_wp_page(mm
, vma
, address
, page_table
, pmd
, ptl
, pte
);
2601 if (ret
& VM_FAULT_ERROR
)
2602 ret
&= VM_FAULT_ERROR
;
2606 /* No need to invalidate - it was non-present before */
2607 update_mmu_cache(vma
, address
, pte
);
2609 pte_unmap_unlock(page_table
, ptl
);
2613 mem_cgroup_cancel_charge_swapin(ptr
);
2614 pte_unmap_unlock(page_table
, ptl
);
2617 page_cache_release(page
);
2622 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2623 * but allow concurrent faults), and pte mapped but not yet locked.
2624 * We return with mmap_sem still held, but pte unmapped and unlocked.
2626 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2627 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2634 /* Allocate our own private page. */
2635 pte_unmap(page_table
);
2637 if (unlikely(anon_vma_prepare(vma
)))
2639 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2642 __SetPageUptodate(page
);
2644 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
))
2647 entry
= mk_pte(page
, vma
->vm_page_prot
);
2648 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2650 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2651 if (!pte_none(*page_table
))
2654 inc_mm_counter(mm
, anon_rss
);
2655 page_add_new_anon_rmap(page
, vma
, address
);
2656 set_pte_at(mm
, address
, page_table
, entry
);
2658 /* No need to invalidate - it was non-present before */
2659 update_mmu_cache(vma
, address
, entry
);
2661 pte_unmap_unlock(page_table
, ptl
);
2664 mem_cgroup_uncharge_page(page
);
2665 page_cache_release(page
);
2668 page_cache_release(page
);
2670 return VM_FAULT_OOM
;
2674 * __do_fault() tries to create a new page mapping. It aggressively
2675 * tries to share with existing pages, but makes a separate copy if
2676 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2677 * the next page fault.
2679 * As this is called only for pages that do not currently exist, we
2680 * do not need to flush old virtual caches or the TLB.
2682 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2683 * but allow concurrent faults), and pte neither mapped nor locked.
2684 * We return with mmap_sem still held, but pte unmapped and unlocked.
2686 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2687 unsigned long address
, pmd_t
*pmd
,
2688 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
2696 struct page
*dirty_page
= NULL
;
2697 struct vm_fault vmf
;
2699 int page_mkwrite
= 0;
2701 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
2706 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
2707 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2711 * For consistency in subsequent calls, make the faulted page always
2714 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
2715 lock_page(vmf
.page
);
2717 VM_BUG_ON(!PageLocked(vmf
.page
));
2720 * Should we do an early C-O-W break?
2723 if (flags
& FAULT_FLAG_WRITE
) {
2724 if (!(vma
->vm_flags
& VM_SHARED
)) {
2726 if (unlikely(anon_vma_prepare(vma
))) {
2730 page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
,
2736 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
)) {
2738 page_cache_release(page
);
2743 * Don't let another task, with possibly unlocked vma,
2744 * keep the mlocked page.
2746 if (vma
->vm_flags
& VM_LOCKED
)
2747 clear_page_mlock(vmf
.page
);
2748 copy_user_highpage(page
, vmf
.page
, address
, vma
);
2749 __SetPageUptodate(page
);
2752 * If the page will be shareable, see if the backing
2753 * address space wants to know that the page is about
2754 * to become writable
2756 if (vma
->vm_ops
->page_mkwrite
) {
2760 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2761 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2763 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2765 goto unwritable_page
;
2767 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2769 if (!page
->mapping
) {
2770 ret
= 0; /* retry the fault */
2772 goto unwritable_page
;
2775 VM_BUG_ON(!PageLocked(page
));
2782 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2785 * This silly early PAGE_DIRTY setting removes a race
2786 * due to the bad i386 page protection. But it's valid
2787 * for other architectures too.
2789 * Note that if FAULT_FLAG_WRITE is set, we either now have
2790 * an exclusive copy of the page, or this is a shared mapping,
2791 * so we can make it writable and dirty to avoid having to
2792 * handle that later.
2794 /* Only go through if we didn't race with anybody else... */
2795 if (likely(pte_same(*page_table
, orig_pte
))) {
2796 flush_icache_page(vma
, page
);
2797 entry
= mk_pte(page
, vma
->vm_page_prot
);
2798 if (flags
& FAULT_FLAG_WRITE
)
2799 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2801 inc_mm_counter(mm
, anon_rss
);
2802 page_add_new_anon_rmap(page
, vma
, address
);
2804 inc_mm_counter(mm
, file_rss
);
2805 page_add_file_rmap(page
);
2806 if (flags
& FAULT_FLAG_WRITE
) {
2808 get_page(dirty_page
);
2811 set_pte_at(mm
, address
, page_table
, entry
);
2813 /* no need to invalidate: a not-present page won't be cached */
2814 update_mmu_cache(vma
, address
, entry
);
2817 mem_cgroup_uncharge_page(page
);
2819 page_cache_release(page
);
2821 anon
= 1; /* no anon but release faulted_page */
2824 pte_unmap_unlock(page_table
, ptl
);
2828 struct address_space
*mapping
= page
->mapping
;
2830 if (set_page_dirty(dirty_page
))
2832 unlock_page(dirty_page
);
2833 put_page(dirty_page
);
2834 if (page_mkwrite
&& mapping
) {
2836 * Some device drivers do not set page.mapping but still
2839 balance_dirty_pages_ratelimited(mapping
);
2842 /* file_update_time outside page_lock */
2844 file_update_time(vma
->vm_file
);
2846 unlock_page(vmf
.page
);
2848 page_cache_release(vmf
.page
);
2854 page_cache_release(page
);
2858 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2859 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2860 unsigned int flags
, pte_t orig_pte
)
2862 pgoff_t pgoff
= (((address
& PAGE_MASK
)
2863 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2865 pte_unmap(page_table
);
2866 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2870 * Fault of a previously existing named mapping. Repopulate the pte
2871 * from the encoded file_pte if possible. This enables swappable
2874 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2875 * but allow concurrent faults), and pte mapped but not yet locked.
2876 * We return with mmap_sem still held, but pte unmapped and unlocked.
2878 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2879 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2880 unsigned int flags
, pte_t orig_pte
)
2884 flags
|= FAULT_FLAG_NONLINEAR
;
2886 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2889 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
2891 * Page table corrupted: show pte and kill process.
2893 print_bad_pte(vma
, address
, orig_pte
, NULL
);
2894 return VM_FAULT_OOM
;
2897 pgoff
= pte_to_pgoff(orig_pte
);
2898 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2902 * These routines also need to handle stuff like marking pages dirty
2903 * and/or accessed for architectures that don't do it in hardware (most
2904 * RISC architectures). The early dirtying is also good on the i386.
2906 * There is also a hook called "update_mmu_cache()" that architectures
2907 * with external mmu caches can use to update those (ie the Sparc or
2908 * PowerPC hashed page tables that act as extended TLBs).
2910 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2911 * but allow concurrent faults), and pte mapped but not yet locked.
2912 * We return with mmap_sem still held, but pte unmapped and unlocked.
2914 static inline int handle_pte_fault(struct mm_struct
*mm
,
2915 struct vm_area_struct
*vma
, unsigned long address
,
2916 pte_t
*pte
, pmd_t
*pmd
, unsigned int flags
)
2922 if (!pte_present(entry
)) {
2923 if (pte_none(entry
)) {
2925 if (likely(vma
->vm_ops
->fault
))
2926 return do_linear_fault(mm
, vma
, address
,
2927 pte
, pmd
, flags
, entry
);
2929 return do_anonymous_page(mm
, vma
, address
,
2932 if (pte_file(entry
))
2933 return do_nonlinear_fault(mm
, vma
, address
,
2934 pte
, pmd
, flags
, entry
);
2935 return do_swap_page(mm
, vma
, address
,
2936 pte
, pmd
, flags
, entry
);
2939 ptl
= pte_lockptr(mm
, pmd
);
2941 if (unlikely(!pte_same(*pte
, entry
)))
2943 if (flags
& FAULT_FLAG_WRITE
) {
2944 if (!pte_write(entry
))
2945 return do_wp_page(mm
, vma
, address
,
2946 pte
, pmd
, ptl
, entry
);
2947 entry
= pte_mkdirty(entry
);
2949 entry
= pte_mkyoung(entry
);
2950 if (ptep_set_access_flags(vma
, address
, pte
, entry
, flags
& FAULT_FLAG_WRITE
)) {
2951 update_mmu_cache(vma
, address
, entry
);
2954 * This is needed only for protection faults but the arch code
2955 * is not yet telling us if this is a protection fault or not.
2956 * This still avoids useless tlb flushes for .text page faults
2959 if (flags
& FAULT_FLAG_WRITE
)
2960 flush_tlb_page(vma
, address
);
2963 pte_unmap_unlock(pte
, ptl
);
2968 * By the time we get here, we already hold the mm semaphore
2970 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2971 unsigned long address
, unsigned int flags
)
2978 __set_current_state(TASK_RUNNING
);
2980 count_vm_event(PGFAULT
);
2982 if (unlikely(is_vm_hugetlb_page(vma
)))
2983 return hugetlb_fault(mm
, vma
, address
, flags
);
2985 pgd
= pgd_offset(mm
, address
);
2986 pud
= pud_alloc(mm
, pgd
, address
);
2988 return VM_FAULT_OOM
;
2989 pmd
= pmd_alloc(mm
, pud
, address
);
2991 return VM_FAULT_OOM
;
2992 pte
= pte_alloc_map(mm
, pmd
, address
);
2994 return VM_FAULT_OOM
;
2996 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, flags
);
2999 #ifndef __PAGETABLE_PUD_FOLDED
3001 * Allocate page upper directory.
3002 * We've already handled the fast-path in-line.
3004 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
3006 pud_t
*new = pud_alloc_one(mm
, address
);
3010 smp_wmb(); /* See comment in __pte_alloc */
3012 spin_lock(&mm
->page_table_lock
);
3013 if (pgd_present(*pgd
)) /* Another has populated it */
3016 pgd_populate(mm
, pgd
, new);
3017 spin_unlock(&mm
->page_table_lock
);
3020 #endif /* __PAGETABLE_PUD_FOLDED */
3022 #ifndef __PAGETABLE_PMD_FOLDED
3024 * Allocate page middle directory.
3025 * We've already handled the fast-path in-line.
3027 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
3029 pmd_t
*new = pmd_alloc_one(mm
, address
);
3033 smp_wmb(); /* See comment in __pte_alloc */
3035 spin_lock(&mm
->page_table_lock
);
3036 #ifndef __ARCH_HAS_4LEVEL_HACK
3037 if (pud_present(*pud
)) /* Another has populated it */
3040 pud_populate(mm
, pud
, new);
3042 if (pgd_present(*pud
)) /* Another has populated it */
3045 pgd_populate(mm
, pud
, new);
3046 #endif /* __ARCH_HAS_4LEVEL_HACK */
3047 spin_unlock(&mm
->page_table_lock
);
3050 #endif /* __PAGETABLE_PMD_FOLDED */
3052 int make_pages_present(unsigned long addr
, unsigned long end
)
3054 int ret
, len
, write
;
3055 struct vm_area_struct
* vma
;
3057 vma
= find_vma(current
->mm
, addr
);
3060 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
3061 BUG_ON(addr
>= end
);
3062 BUG_ON(end
> vma
->vm_end
);
3063 len
= DIV_ROUND_UP(end
, PAGE_SIZE
) - addr
/PAGE_SIZE
;
3064 ret
= get_user_pages(current
, current
->mm
, addr
,
3065 len
, write
, 0, NULL
, NULL
);
3068 return ret
== len
? 0 : -EFAULT
;
3071 #if !defined(__HAVE_ARCH_GATE_AREA)
3073 #if defined(AT_SYSINFO_EHDR)
3074 static struct vm_area_struct gate_vma
;
3076 static int __init
gate_vma_init(void)
3078 gate_vma
.vm_mm
= NULL
;
3079 gate_vma
.vm_start
= FIXADDR_USER_START
;
3080 gate_vma
.vm_end
= FIXADDR_USER_END
;
3081 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
3082 gate_vma
.vm_page_prot
= __P101
;
3084 * Make sure the vDSO gets into every core dump.
3085 * Dumping its contents makes post-mortem fully interpretable later
3086 * without matching up the same kernel and hardware config to see
3087 * what PC values meant.
3089 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
3092 __initcall(gate_vma_init
);
3095 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
3097 #ifdef AT_SYSINFO_EHDR
3104 int in_gate_area_no_task(unsigned long addr
)
3106 #ifdef AT_SYSINFO_EHDR
3107 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
3113 #endif /* __HAVE_ARCH_GATE_AREA */
3115 static int follow_pte(struct mm_struct
*mm
, unsigned long address
,
3116 pte_t
**ptepp
, spinlock_t
**ptlp
)
3123 pgd
= pgd_offset(mm
, address
);
3124 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
3127 pud
= pud_offset(pgd
, address
);
3128 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
3131 pmd
= pmd_offset(pud
, address
);
3132 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
3135 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3139 ptep
= pte_offset_map_lock(mm
, pmd
, address
, ptlp
);
3142 if (!pte_present(*ptep
))
3147 pte_unmap_unlock(ptep
, *ptlp
);
3153 * follow_pfn - look up PFN at a user virtual address
3154 * @vma: memory mapping
3155 * @address: user virtual address
3156 * @pfn: location to store found PFN
3158 * Only IO mappings and raw PFN mappings are allowed.
3160 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3162 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
3169 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3172 ret
= follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
);
3175 *pfn
= pte_pfn(*ptep
);
3176 pte_unmap_unlock(ptep
, ptl
);
3179 EXPORT_SYMBOL(follow_pfn
);
3181 #ifdef CONFIG_HAVE_IOREMAP_PROT
3182 int follow_phys(struct vm_area_struct
*vma
,
3183 unsigned long address
, unsigned int flags
,
3184 unsigned long *prot
, resource_size_t
*phys
)
3190 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3193 if (follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
))
3197 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
3200 *prot
= pgprot_val(pte_pgprot(pte
));
3201 *phys
= (resource_size_t
)pte_pfn(pte
) << PAGE_SHIFT
;
3205 pte_unmap_unlock(ptep
, ptl
);
3210 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
3211 void *buf
, int len
, int write
)
3213 resource_size_t phys_addr
;
3214 unsigned long prot
= 0;
3215 void __iomem
*maddr
;
3216 int offset
= addr
& (PAGE_SIZE
-1);
3218 if (follow_phys(vma
, addr
, write
, &prot
, &phys_addr
))
3221 maddr
= ioremap_prot(phys_addr
, PAGE_SIZE
, prot
);
3223 memcpy_toio(maddr
+ offset
, buf
, len
);
3225 memcpy_fromio(buf
, maddr
+ offset
, len
);
3233 * Access another process' address space.
3234 * Source/target buffer must be kernel space,
3235 * Do not walk the page table directly, use get_user_pages
3237 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
3239 struct mm_struct
*mm
;
3240 struct vm_area_struct
*vma
;
3241 void *old_buf
= buf
;
3243 mm
= get_task_mm(tsk
);
3247 down_read(&mm
->mmap_sem
);
3248 /* ignore errors, just check how much was successfully transferred */
3250 int bytes
, ret
, offset
;
3252 struct page
*page
= NULL
;
3254 ret
= get_user_pages(tsk
, mm
, addr
, 1,
3255 write
, 1, &page
, &vma
);
3258 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3259 * we can access using slightly different code.
3261 #ifdef CONFIG_HAVE_IOREMAP_PROT
3262 vma
= find_vma(mm
, addr
);
3265 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
3266 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
3274 offset
= addr
& (PAGE_SIZE
-1);
3275 if (bytes
> PAGE_SIZE
-offset
)
3276 bytes
= PAGE_SIZE
-offset
;
3280 copy_to_user_page(vma
, page
, addr
,
3281 maddr
+ offset
, buf
, bytes
);
3282 set_page_dirty_lock(page
);
3284 copy_from_user_page(vma
, page
, addr
,
3285 buf
, maddr
+ offset
, bytes
);
3288 page_cache_release(page
);
3294 up_read(&mm
->mmap_sem
);
3297 return buf
- old_buf
;
3301 * Print the name of a VMA.
3303 void print_vma_addr(char *prefix
, unsigned long ip
)
3305 struct mm_struct
*mm
= current
->mm
;
3306 struct vm_area_struct
*vma
;
3309 * Do not print if we are in atomic
3310 * contexts (in exception stacks, etc.):
3312 if (preempt_count())
3315 down_read(&mm
->mmap_sem
);
3316 vma
= find_vma(mm
, ip
);
3317 if (vma
&& vma
->vm_file
) {
3318 struct file
*f
= vma
->vm_file
;
3319 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
3323 p
= d_path(&f
->f_path
, buf
, PAGE_SIZE
);
3326 s
= strrchr(p
, '/');
3329 printk("%s%s[%lx+%lx]", prefix
, p
,
3331 vma
->vm_end
- vma
->vm_start
);
3332 free_page((unsigned long)buf
);
3335 up_read(¤t
->mm
->mmap_sem
);
3338 #ifdef CONFIG_PROVE_LOCKING
3339 void might_fault(void)
3342 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3343 * holding the mmap_sem, this is safe because kernel memory doesn't
3344 * get paged out, therefore we'll never actually fault, and the
3345 * below annotations will generate false positives.
3347 if (segment_eq(get_fs(), KERNEL_DS
))
3352 * it would be nicer only to annotate paths which are not under
3353 * pagefault_disable, however that requires a larger audit and
3354 * providing helpers like get_user_atomic.
3356 if (!in_atomic() && current
->mm
)
3357 might_lock_read(¤t
->mm
->mmap_sem
);
3359 EXPORT_SYMBOL(might_fault
);