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
);
1224 * Require read or write permissions.
1225 * If 'force' is set, we only require the "MAY" flags.
1227 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
1228 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
1232 struct vm_area_struct
*vma
;
1233 unsigned int foll_flags
;
1235 vma
= find_extend_vma(mm
, start
);
1236 if (!vma
&& in_gate_area(tsk
, start
)) {
1237 unsigned long pg
= start
& PAGE_MASK
;
1238 struct vm_area_struct
*gate_vma
= get_gate_vma(tsk
);
1244 /* user gate pages are read-only */
1246 return i
? : -EFAULT
;
1248 pgd
= pgd_offset_k(pg
);
1250 pgd
= pgd_offset_gate(mm
, pg
);
1251 BUG_ON(pgd_none(*pgd
));
1252 pud
= pud_offset(pgd
, pg
);
1253 BUG_ON(pud_none(*pud
));
1254 pmd
= pmd_offset(pud
, pg
);
1256 return i
? : -EFAULT
;
1257 pte
= pte_offset_map(pmd
, pg
);
1258 if (pte_none(*pte
)) {
1260 return i
? : -EFAULT
;
1263 struct page
*page
= vm_normal_page(gate_vma
, start
, *pte
);
1278 (vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
1279 !(vm_flags
& vma
->vm_flags
))
1280 return i
? : -EFAULT
;
1282 if (is_vm_hugetlb_page(vma
)) {
1283 i
= follow_hugetlb_page(mm
, vma
, pages
, vmas
,
1284 &start
, &nr_pages
, i
, write
);
1288 foll_flags
= FOLL_TOUCH
;
1290 foll_flags
|= FOLL_GET
;
1291 if (!write
&& use_zero_page(vma
))
1292 foll_flags
|= FOLL_ANON
;
1298 * If we have a pending SIGKILL, don't keep faulting
1299 * pages and potentially allocating memory.
1301 if (unlikely(fatal_signal_pending(current
)))
1302 return i
? i
: -ERESTARTSYS
;
1305 foll_flags
|= FOLL_WRITE
;
1308 while (!(page
= follow_page(vma
, start
, foll_flags
))) {
1311 ret
= handle_mm_fault(mm
, vma
, start
,
1312 (foll_flags
& FOLL_WRITE
) ?
1313 FAULT_FLAG_WRITE
: 0);
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 (nr_pages
&& start
< vma
->vm_end
);
1364 * get_user_pages() - pin user pages in memory
1365 * @tsk: task_struct of target task
1366 * @mm: mm_struct of target mm
1367 * @start: starting user address
1368 * @nr_pages: number of pages from start to pin
1369 * @write: whether pages will be written to by the caller
1370 * @force: whether to force write access even if user mapping is
1371 * readonly. This will result in the page being COWed even
1372 * in MAP_SHARED mappings. You do not want this.
1373 * @pages: array that receives pointers to the pages pinned.
1374 * Should be at least nr_pages long. Or NULL, if caller
1375 * only intends to ensure the pages are faulted in.
1376 * @vmas: array of pointers to vmas corresponding to each page.
1377 * Or NULL if the caller does not require them.
1379 * Returns number of pages pinned. This may be fewer than the number
1380 * requested. If nr_pages is 0 or negative, returns 0. If no pages
1381 * were pinned, returns -errno. Each page returned must be released
1382 * with a put_page() call when it is finished with. vmas will only
1383 * remain valid while mmap_sem is held.
1385 * Must be called with mmap_sem held for read or write.
1387 * get_user_pages walks a process's page tables and takes a reference to
1388 * each struct page that each user address corresponds to at a given
1389 * instant. That is, it takes the page that would be accessed if a user
1390 * thread accesses the given user virtual address at that instant.
1392 * This does not guarantee that the page exists in the user mappings when
1393 * get_user_pages returns, and there may even be a completely different
1394 * page there in some cases (eg. if mmapped pagecache has been invalidated
1395 * and subsequently re faulted). However it does guarantee that the page
1396 * won't be freed completely. And mostly callers simply care that the page
1397 * contains data that was valid *at some point in time*. Typically, an IO
1398 * or similar operation cannot guarantee anything stronger anyway because
1399 * locks can't be held over the syscall boundary.
1401 * If write=0, the page must not be written to. If the page is written to,
1402 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1403 * after the page is finished with, and before put_page is called.
1405 * get_user_pages is typically used for fewer-copy IO operations, to get a
1406 * handle on the memory by some means other than accesses via the user virtual
1407 * addresses. The pages may be submitted for DMA to devices or accessed via
1408 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1409 * use the correct cache flushing APIs.
1411 * See also get_user_pages_fast, for performance critical applications.
1413 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
1414 unsigned long start
, int nr_pages
, int write
, int force
,
1415 struct page
**pages
, struct vm_area_struct
**vmas
)
1420 flags
|= GUP_FLAGS_WRITE
;
1422 flags
|= GUP_FLAGS_FORCE
;
1424 return __get_user_pages(tsk
, mm
, start
, nr_pages
, flags
, pages
, vmas
);
1427 EXPORT_SYMBOL(get_user_pages
);
1429 pte_t
*get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
1432 pgd_t
* pgd
= pgd_offset(mm
, addr
);
1433 pud_t
* pud
= pud_alloc(mm
, pgd
, addr
);
1435 pmd_t
* pmd
= pmd_alloc(mm
, pud
, addr
);
1437 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1443 * This is the old fallback for page remapping.
1445 * For historical reasons, it only allows reserved pages. Only
1446 * old drivers should use this, and they needed to mark their
1447 * pages reserved for the old functions anyway.
1449 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1450 struct page
*page
, pgprot_t prot
)
1452 struct mm_struct
*mm
= vma
->vm_mm
;
1461 flush_dcache_page(page
);
1462 pte
= get_locked_pte(mm
, addr
, &ptl
);
1466 if (!pte_none(*pte
))
1469 /* Ok, finally just insert the thing.. */
1471 inc_mm_counter(mm
, file_rss
);
1472 page_add_file_rmap(page
);
1473 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1476 pte_unmap_unlock(pte
, ptl
);
1479 pte_unmap_unlock(pte
, ptl
);
1485 * vm_insert_page - insert single page into user vma
1486 * @vma: user vma to map to
1487 * @addr: target user address of this page
1488 * @page: source kernel page
1490 * This allows drivers to insert individual pages they've allocated
1493 * The page has to be a nice clean _individual_ kernel allocation.
1494 * If you allocate a compound page, you need to have marked it as
1495 * such (__GFP_COMP), or manually just split the page up yourself
1496 * (see split_page()).
1498 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1499 * took an arbitrary page protection parameter. This doesn't allow
1500 * that. Your vma protection will have to be set up correctly, which
1501 * means that if you want a shared writable mapping, you'd better
1502 * ask for a shared writable mapping!
1504 * The page does not need to be reserved.
1506 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1509 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1511 if (!page_count(page
))
1513 vma
->vm_flags
|= VM_INSERTPAGE
;
1514 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1516 EXPORT_SYMBOL(vm_insert_page
);
1518 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1519 unsigned long pfn
, pgprot_t prot
)
1521 struct mm_struct
*mm
= vma
->vm_mm
;
1527 pte
= get_locked_pte(mm
, addr
, &ptl
);
1531 if (!pte_none(*pte
))
1534 /* Ok, finally just insert the thing.. */
1535 entry
= pte_mkspecial(pfn_pte(pfn
, prot
));
1536 set_pte_at(mm
, addr
, pte
, entry
);
1537 update_mmu_cache(vma
, addr
, entry
); /* XXX: why not for insert_page? */
1541 pte_unmap_unlock(pte
, ptl
);
1547 * vm_insert_pfn - insert single pfn into user vma
1548 * @vma: user vma to map to
1549 * @addr: target user address of this page
1550 * @pfn: source kernel pfn
1552 * Similar to vm_inert_page, this allows drivers to insert individual pages
1553 * they've allocated into a user vma. Same comments apply.
1555 * This function should only be called from a vm_ops->fault handler, and
1556 * in that case the handler should return NULL.
1558 * vma cannot be a COW mapping.
1560 * As this is called only for pages that do not currently exist, we
1561 * do not need to flush old virtual caches or the TLB.
1563 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1567 pgprot_t pgprot
= vma
->vm_page_prot
;
1569 * Technically, architectures with pte_special can avoid all these
1570 * restrictions (same for remap_pfn_range). However we would like
1571 * consistency in testing and feature parity among all, so we should
1572 * try to keep these invariants in place for everybody.
1574 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
1575 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
1576 (VM_PFNMAP
|VM_MIXEDMAP
));
1577 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
1578 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
1580 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1582 if (track_pfn_vma_new(vma
, &pgprot
, pfn
, PAGE_SIZE
))
1585 ret
= insert_pfn(vma
, addr
, pfn
, pgprot
);
1588 untrack_pfn_vma(vma
, pfn
, PAGE_SIZE
);
1592 EXPORT_SYMBOL(vm_insert_pfn
);
1594 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1597 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
1599 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1603 * If we don't have pte special, then we have to use the pfn_valid()
1604 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1605 * refcount the page if pfn_valid is true (hence insert_page rather
1608 if (!HAVE_PTE_SPECIAL
&& pfn_valid(pfn
)) {
1611 page
= pfn_to_page(pfn
);
1612 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1614 return insert_pfn(vma
, addr
, pfn
, vma
->vm_page_prot
);
1616 EXPORT_SYMBOL(vm_insert_mixed
);
1619 * maps a range of physical memory into the requested pages. the old
1620 * mappings are removed. any references to nonexistent pages results
1621 * in null mappings (currently treated as "copy-on-access")
1623 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1624 unsigned long addr
, unsigned long end
,
1625 unsigned long pfn
, pgprot_t prot
)
1630 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1633 arch_enter_lazy_mmu_mode();
1635 BUG_ON(!pte_none(*pte
));
1636 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
1638 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1639 arch_leave_lazy_mmu_mode();
1640 pte_unmap_unlock(pte
- 1, ptl
);
1644 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1645 unsigned long addr
, unsigned long end
,
1646 unsigned long pfn
, pgprot_t prot
)
1651 pfn
-= addr
>> PAGE_SHIFT
;
1652 pmd
= pmd_alloc(mm
, pud
, addr
);
1656 next
= pmd_addr_end(addr
, end
);
1657 if (remap_pte_range(mm
, pmd
, addr
, next
,
1658 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1660 } while (pmd
++, addr
= next
, addr
!= end
);
1664 static inline int remap_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1665 unsigned long addr
, unsigned long end
,
1666 unsigned long pfn
, pgprot_t prot
)
1671 pfn
-= addr
>> PAGE_SHIFT
;
1672 pud
= pud_alloc(mm
, pgd
, addr
);
1676 next
= pud_addr_end(addr
, end
);
1677 if (remap_pmd_range(mm
, pud
, addr
, next
,
1678 pfn
+ (addr
>> PAGE_SHIFT
), prot
))
1680 } while (pud
++, addr
= next
, addr
!= end
);
1685 * remap_pfn_range - remap kernel memory to userspace
1686 * @vma: user vma to map to
1687 * @addr: target user address to start at
1688 * @pfn: physical address of kernel memory
1689 * @size: size of map area
1690 * @prot: page protection flags for this mapping
1692 * Note: this is only safe if the mm semaphore is held when called.
1694 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1695 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1699 unsigned long end
= addr
+ PAGE_ALIGN(size
);
1700 struct mm_struct
*mm
= vma
->vm_mm
;
1704 * Physically remapped pages are special. Tell the
1705 * rest of the world about it:
1706 * VM_IO tells people not to look at these pages
1707 * (accesses can have side effects).
1708 * VM_RESERVED is specified all over the place, because
1709 * in 2.4 it kept swapout's vma scan off this vma; but
1710 * in 2.6 the LRU scan won't even find its pages, so this
1711 * flag means no more than count its pages in reserved_vm,
1712 * and omit it from core dump, even when VM_IO turned off.
1713 * VM_PFNMAP tells the core MM that the base pages are just
1714 * raw PFN mappings, and do not have a "struct page" associated
1717 * There's a horrible special case to handle copy-on-write
1718 * behaviour that some programs depend on. We mark the "original"
1719 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1721 if (addr
== vma
->vm_start
&& end
== vma
->vm_end
) {
1722 vma
->vm_pgoff
= pfn
;
1723 vma
->vm_flags
|= VM_PFN_AT_MMAP
;
1724 } else if (is_cow_mapping(vma
->vm_flags
))
1727 vma
->vm_flags
|= VM_IO
| VM_RESERVED
| VM_PFNMAP
;
1729 err
= track_pfn_vma_new(vma
, &prot
, pfn
, PAGE_ALIGN(size
));
1732 * To indicate that track_pfn related cleanup is not
1733 * needed from higher level routine calling unmap_vmas
1735 vma
->vm_flags
&= ~(VM_IO
| VM_RESERVED
| VM_PFNMAP
);
1736 vma
->vm_flags
&= ~VM_PFN_AT_MMAP
;
1740 BUG_ON(addr
>= end
);
1741 pfn
-= addr
>> PAGE_SHIFT
;
1742 pgd
= pgd_offset(mm
, addr
);
1743 flush_cache_range(vma
, addr
, end
);
1745 next
= pgd_addr_end(addr
, end
);
1746 err
= remap_pud_range(mm
, pgd
, addr
, next
,
1747 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
1750 } while (pgd
++, addr
= next
, addr
!= end
);
1753 untrack_pfn_vma(vma
, pfn
, PAGE_ALIGN(size
));
1757 EXPORT_SYMBOL(remap_pfn_range
);
1759 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1760 unsigned long addr
, unsigned long end
,
1761 pte_fn_t fn
, void *data
)
1766 spinlock_t
*uninitialized_var(ptl
);
1768 pte
= (mm
== &init_mm
) ?
1769 pte_alloc_kernel(pmd
, addr
) :
1770 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1774 BUG_ON(pmd_huge(*pmd
));
1776 arch_enter_lazy_mmu_mode();
1778 token
= pmd_pgtable(*pmd
);
1781 err
= fn(pte
, token
, addr
, data
);
1784 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1786 arch_leave_lazy_mmu_mode();
1789 pte_unmap_unlock(pte
-1, ptl
);
1793 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1794 unsigned long addr
, unsigned long end
,
1795 pte_fn_t fn
, void *data
)
1801 BUG_ON(pud_huge(*pud
));
1803 pmd
= pmd_alloc(mm
, pud
, addr
);
1807 next
= pmd_addr_end(addr
, end
);
1808 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
1811 } while (pmd
++, addr
= next
, addr
!= end
);
1815 static int apply_to_pud_range(struct mm_struct
*mm
, pgd_t
*pgd
,
1816 unsigned long addr
, unsigned long end
,
1817 pte_fn_t fn
, void *data
)
1823 pud
= pud_alloc(mm
, pgd
, addr
);
1827 next
= pud_addr_end(addr
, end
);
1828 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
1831 } while (pud
++, addr
= next
, addr
!= end
);
1836 * Scan a region of virtual memory, filling in page tables as necessary
1837 * and calling a provided function on each leaf page table.
1839 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
1840 unsigned long size
, pte_fn_t fn
, void *data
)
1844 unsigned long start
= addr
, end
= addr
+ size
;
1847 BUG_ON(addr
>= end
);
1848 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1849 pgd
= pgd_offset(mm
, addr
);
1851 next
= pgd_addr_end(addr
, end
);
1852 err
= apply_to_pud_range(mm
, pgd
, addr
, next
, fn
, data
);
1855 } while (pgd
++, addr
= next
, addr
!= end
);
1856 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1859 EXPORT_SYMBOL_GPL(apply_to_page_range
);
1862 * handle_pte_fault chooses page fault handler according to an entry
1863 * which was read non-atomically. Before making any commitment, on
1864 * those architectures or configurations (e.g. i386 with PAE) which
1865 * might give a mix of unmatched parts, do_swap_page and do_file_page
1866 * must check under lock before unmapping the pte and proceeding
1867 * (but do_wp_page is only called after already making such a check;
1868 * and do_anonymous_page and do_no_page can safely check later on).
1870 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
1871 pte_t
*page_table
, pte_t orig_pte
)
1874 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1875 if (sizeof(pte_t
) > sizeof(unsigned long)) {
1876 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
1878 same
= pte_same(*page_table
, orig_pte
);
1882 pte_unmap(page_table
);
1887 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1888 * servicing faults for write access. In the normal case, do always want
1889 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1890 * that do not have writing enabled, when used by access_process_vm.
1892 static inline pte_t
maybe_mkwrite(pte_t pte
, struct vm_area_struct
*vma
)
1894 if (likely(vma
->vm_flags
& VM_WRITE
))
1895 pte
= pte_mkwrite(pte
);
1899 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
1902 * If the source page was a PFN mapping, we don't have
1903 * a "struct page" for it. We do a best-effort copy by
1904 * just copying from the original user address. If that
1905 * fails, we just zero-fill it. Live with it.
1907 if (unlikely(!src
)) {
1908 void *kaddr
= kmap_atomic(dst
, KM_USER0
);
1909 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
1912 * This really shouldn't fail, because the page is there
1913 * in the page tables. But it might just be unreadable,
1914 * in which case we just give up and fill the result with
1917 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
1918 memset(kaddr
, 0, PAGE_SIZE
);
1919 kunmap_atomic(kaddr
, KM_USER0
);
1920 flush_dcache_page(dst
);
1922 copy_user_highpage(dst
, src
, va
, vma
);
1926 * This routine handles present pages, when users try to write
1927 * to a shared page. It is done by copying the page to a new address
1928 * and decrementing the shared-page counter for the old page.
1930 * Note that this routine assumes that the protection checks have been
1931 * done by the caller (the low-level page fault routine in most cases).
1932 * Thus we can safely just mark it writable once we've done any necessary
1935 * We also mark the page dirty at this point even though the page will
1936 * change only once the write actually happens. This avoids a few races,
1937 * and potentially makes it more efficient.
1939 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1940 * but allow concurrent faults), with pte both mapped and locked.
1941 * We return with mmap_sem still held, but pte unmapped and unlocked.
1943 static int do_wp_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1944 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
1945 spinlock_t
*ptl
, pte_t orig_pte
)
1947 struct page
*old_page
, *new_page
;
1949 int reuse
= 0, ret
= 0;
1950 int page_mkwrite
= 0;
1951 struct page
*dirty_page
= NULL
;
1953 old_page
= vm_normal_page(vma
, address
, orig_pte
);
1956 * VM_MIXEDMAP !pfn_valid() case
1958 * We should not cow pages in a shared writeable mapping.
1959 * Just mark the pages writable as we can't do any dirty
1960 * accounting on raw pfn maps.
1962 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1963 (VM_WRITE
|VM_SHARED
))
1969 * Take out anonymous pages first, anonymous shared vmas are
1970 * not dirty accountable.
1972 if (PageAnon(old_page
) && !PageKsm(old_page
)) {
1973 if (!trylock_page(old_page
)) {
1974 page_cache_get(old_page
);
1975 pte_unmap_unlock(page_table
, ptl
);
1976 lock_page(old_page
);
1977 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
1979 if (!pte_same(*page_table
, orig_pte
)) {
1980 unlock_page(old_page
);
1981 page_cache_release(old_page
);
1984 page_cache_release(old_page
);
1986 reuse
= reuse_swap_page(old_page
);
1987 unlock_page(old_page
);
1988 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
1989 (VM_WRITE
|VM_SHARED
))) {
1991 * Only catch write-faults on shared writable pages,
1992 * read-only shared pages can get COWed by
1993 * get_user_pages(.write=1, .force=1).
1995 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
1996 struct vm_fault vmf
;
1999 vmf
.virtual_address
= (void __user
*)(address
&
2001 vmf
.pgoff
= old_page
->index
;
2002 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2003 vmf
.page
= old_page
;
2006 * Notify the address space that the page is about to
2007 * become writable so that it can prohibit this or wait
2008 * for the page to get into an appropriate state.
2010 * We do this without the lock held, so that it can
2011 * sleep if it needs to.
2013 page_cache_get(old_page
);
2014 pte_unmap_unlock(page_table
, ptl
);
2016 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2018 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2020 goto unwritable_page
;
2022 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2023 lock_page(old_page
);
2024 if (!old_page
->mapping
) {
2025 ret
= 0; /* retry the fault */
2026 unlock_page(old_page
);
2027 goto unwritable_page
;
2030 VM_BUG_ON(!PageLocked(old_page
));
2033 * Since we dropped the lock we need to revalidate
2034 * the PTE as someone else may have changed it. If
2035 * they did, we just return, as we can count on the
2036 * MMU to tell us if they didn't also make it writable.
2038 page_table
= pte_offset_map_lock(mm
, pmd
, address
,
2040 if (!pte_same(*page_table
, orig_pte
)) {
2041 unlock_page(old_page
);
2042 page_cache_release(old_page
);
2048 dirty_page
= old_page
;
2049 get_page(dirty_page
);
2055 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2056 entry
= pte_mkyoung(orig_pte
);
2057 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2058 if (ptep_set_access_flags(vma
, address
, page_table
, entry
,1))
2059 update_mmu_cache(vma
, address
, entry
);
2060 ret
|= VM_FAULT_WRITE
;
2065 * Ok, we need to copy. Oh, well..
2067 page_cache_get(old_page
);
2069 pte_unmap_unlock(page_table
, ptl
);
2071 if (unlikely(anon_vma_prepare(vma
)))
2073 VM_BUG_ON(old_page
== ZERO_PAGE(0));
2074 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, address
);
2078 * Don't let another task, with possibly unlocked vma,
2079 * keep the mlocked page.
2081 if ((vma
->vm_flags
& VM_LOCKED
) && old_page
) {
2082 lock_page(old_page
); /* for LRU manipulation */
2083 clear_page_mlock(old_page
);
2084 unlock_page(old_page
);
2086 cow_user_page(new_page
, old_page
, address
, vma
);
2087 __SetPageUptodate(new_page
);
2089 if (mem_cgroup_newpage_charge(new_page
, mm
, GFP_KERNEL
))
2093 * Re-check the pte - we dropped the lock
2095 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2096 if (likely(pte_same(*page_table
, orig_pte
))) {
2098 if (!PageAnon(old_page
)) {
2099 dec_mm_counter(mm
, file_rss
);
2100 inc_mm_counter(mm
, anon_rss
);
2103 inc_mm_counter(mm
, anon_rss
);
2104 flush_cache_page(vma
, address
, pte_pfn(orig_pte
));
2105 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2106 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2108 * Clear the pte entry and flush it first, before updating the
2109 * pte with the new entry. This will avoid a race condition
2110 * seen in the presence of one thread doing SMC and another
2113 ptep_clear_flush(vma
, address
, page_table
);
2114 page_add_new_anon_rmap(new_page
, vma
, address
);
2116 * We call the notify macro here because, when using secondary
2117 * mmu page tables (such as kvm shadow page tables), we want the
2118 * new page to be mapped directly into the secondary page table.
2120 set_pte_at_notify(mm
, address
, page_table
, entry
);
2121 update_mmu_cache(vma
, address
, entry
);
2124 * Only after switching the pte to the new page may
2125 * we remove the mapcount here. Otherwise another
2126 * process may come and find the rmap count decremented
2127 * before the pte is switched to the new page, and
2128 * "reuse" the old page writing into it while our pte
2129 * here still points into it and can be read by other
2132 * The critical issue is to order this
2133 * page_remove_rmap with the ptp_clear_flush above.
2134 * Those stores are ordered by (if nothing else,)
2135 * the barrier present in the atomic_add_negative
2136 * in page_remove_rmap.
2138 * Then the TLB flush in ptep_clear_flush ensures that
2139 * no process can access the old page before the
2140 * decremented mapcount is visible. And the old page
2141 * cannot be reused until after the decremented
2142 * mapcount is visible. So transitively, TLBs to
2143 * old page will be flushed before it can be reused.
2145 page_remove_rmap(old_page
);
2148 /* Free the old page.. */
2149 new_page
= old_page
;
2150 ret
|= VM_FAULT_WRITE
;
2152 mem_cgroup_uncharge_page(new_page
);
2155 page_cache_release(new_page
);
2157 page_cache_release(old_page
);
2159 pte_unmap_unlock(page_table
, ptl
);
2162 * Yes, Virginia, this is actually required to prevent a race
2163 * with clear_page_dirty_for_io() from clearing the page dirty
2164 * bit after it clear all dirty ptes, but before a racing
2165 * do_wp_page installs a dirty pte.
2167 * do_no_page is protected similarly.
2169 if (!page_mkwrite
) {
2170 wait_on_page_locked(dirty_page
);
2171 set_page_dirty_balance(dirty_page
, page_mkwrite
);
2173 put_page(dirty_page
);
2175 struct address_space
*mapping
= dirty_page
->mapping
;
2177 set_page_dirty(dirty_page
);
2178 unlock_page(dirty_page
);
2179 page_cache_release(dirty_page
);
2182 * Some device drivers do not set page.mapping
2183 * but still dirty their pages
2185 balance_dirty_pages_ratelimited(mapping
);
2189 /* file_update_time outside page_lock */
2191 file_update_time(vma
->vm_file
);
2195 page_cache_release(new_page
);
2199 unlock_page(old_page
);
2200 page_cache_release(old_page
);
2202 page_cache_release(old_page
);
2204 return VM_FAULT_OOM
;
2207 page_cache_release(old_page
);
2212 * Helper functions for unmap_mapping_range().
2214 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2216 * We have to restart searching the prio_tree whenever we drop the lock,
2217 * since the iterator is only valid while the lock is held, and anyway
2218 * a later vma might be split and reinserted earlier while lock dropped.
2220 * The list of nonlinear vmas could be handled more efficiently, using
2221 * a placeholder, but handle it in the same way until a need is shown.
2222 * It is important to search the prio_tree before nonlinear list: a vma
2223 * may become nonlinear and be shifted from prio_tree to nonlinear list
2224 * while the lock is dropped; but never shifted from list to prio_tree.
2226 * In order to make forward progress despite restarting the search,
2227 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2228 * quickly skip it next time around. Since the prio_tree search only
2229 * shows us those vmas affected by unmapping the range in question, we
2230 * can't efficiently keep all vmas in step with mapping->truncate_count:
2231 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2232 * mapping->truncate_count and vma->vm_truncate_count are protected by
2235 * In order to make forward progress despite repeatedly restarting some
2236 * large vma, note the restart_addr from unmap_vmas when it breaks out:
2237 * and restart from that address when we reach that vma again. It might
2238 * have been split or merged, shrunk or extended, but never shifted: so
2239 * restart_addr remains valid so long as it remains in the vma's range.
2240 * unmap_mapping_range forces truncate_count to leap over page-aligned
2241 * values so we can save vma's restart_addr in its truncate_count field.
2243 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2245 static void reset_vma_truncate_counts(struct address_space
*mapping
)
2247 struct vm_area_struct
*vma
;
2248 struct prio_tree_iter iter
;
2250 vma_prio_tree_foreach(vma
, &iter
, &mapping
->i_mmap
, 0, ULONG_MAX
)
2251 vma
->vm_truncate_count
= 0;
2252 list_for_each_entry(vma
, &mapping
->i_mmap_nonlinear
, shared
.vm_set
.list
)
2253 vma
->vm_truncate_count
= 0;
2256 static int unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2257 unsigned long start_addr
, unsigned long end_addr
,
2258 struct zap_details
*details
)
2260 unsigned long restart_addr
;
2264 * files that support invalidating or truncating portions of the
2265 * file from under mmaped areas must have their ->fault function
2266 * return a locked page (and set VM_FAULT_LOCKED in the return).
2267 * This provides synchronisation against concurrent unmapping here.
2271 restart_addr
= vma
->vm_truncate_count
;
2272 if (is_restart_addr(restart_addr
) && start_addr
< restart_addr
) {
2273 start_addr
= restart_addr
;
2274 if (start_addr
>= end_addr
) {
2275 /* Top of vma has been split off since last time */
2276 vma
->vm_truncate_count
= details
->truncate_count
;
2281 restart_addr
= zap_page_range(vma
, start_addr
,
2282 end_addr
- start_addr
, details
);
2283 need_break
= need_resched() || spin_needbreak(details
->i_mmap_lock
);
2285 if (restart_addr
>= end_addr
) {
2286 /* We have now completed this vma: mark it so */
2287 vma
->vm_truncate_count
= details
->truncate_count
;
2291 /* Note restart_addr in vma's truncate_count field */
2292 vma
->vm_truncate_count
= restart_addr
;
2297 spin_unlock(details
->i_mmap_lock
);
2299 spin_lock(details
->i_mmap_lock
);
2303 static inline void unmap_mapping_range_tree(struct prio_tree_root
*root
,
2304 struct zap_details
*details
)
2306 struct vm_area_struct
*vma
;
2307 struct prio_tree_iter iter
;
2308 pgoff_t vba
, vea
, zba
, zea
;
2311 vma_prio_tree_foreach(vma
, &iter
, root
,
2312 details
->first_index
, details
->last_index
) {
2313 /* Skip quickly over those we have already dealt with */
2314 if (vma
->vm_truncate_count
== details
->truncate_count
)
2317 vba
= vma
->vm_pgoff
;
2318 vea
= vba
+ ((vma
->vm_end
- vma
->vm_start
) >> PAGE_SHIFT
) - 1;
2319 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2320 zba
= details
->first_index
;
2323 zea
= details
->last_index
;
2327 if (unmap_mapping_range_vma(vma
,
2328 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2329 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2335 static inline void unmap_mapping_range_list(struct list_head
*head
,
2336 struct zap_details
*details
)
2338 struct vm_area_struct
*vma
;
2341 * In nonlinear VMAs there is no correspondence between virtual address
2342 * offset and file offset. So we must perform an exhaustive search
2343 * across *all* the pages in each nonlinear VMA, not just the pages
2344 * whose virtual address lies outside the file truncation point.
2347 list_for_each_entry(vma
, head
, shared
.vm_set
.list
) {
2348 /* Skip quickly over those we have already dealt with */
2349 if (vma
->vm_truncate_count
== details
->truncate_count
)
2351 details
->nonlinear_vma
= vma
;
2352 if (unmap_mapping_range_vma(vma
, vma
->vm_start
,
2353 vma
->vm_end
, details
) < 0)
2359 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2360 * @mapping: the address space containing mmaps to be unmapped.
2361 * @holebegin: byte in first page to unmap, relative to the start of
2362 * the underlying file. This will be rounded down to a PAGE_SIZE
2363 * boundary. Note that this is different from vmtruncate(), which
2364 * must keep the partial page. In contrast, we must get rid of
2366 * @holelen: size of prospective hole in bytes. This will be rounded
2367 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2369 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2370 * but 0 when invalidating pagecache, don't throw away private data.
2372 void unmap_mapping_range(struct address_space
*mapping
,
2373 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2375 struct zap_details details
;
2376 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2377 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2379 /* Check for overflow. */
2380 if (sizeof(holelen
) > sizeof(hlen
)) {
2382 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2383 if (holeend
& ~(long long)ULONG_MAX
)
2384 hlen
= ULONG_MAX
- hba
+ 1;
2387 details
.check_mapping
= even_cows
? NULL
: mapping
;
2388 details
.nonlinear_vma
= NULL
;
2389 details
.first_index
= hba
;
2390 details
.last_index
= hba
+ hlen
- 1;
2391 if (details
.last_index
< details
.first_index
)
2392 details
.last_index
= ULONG_MAX
;
2393 details
.i_mmap_lock
= &mapping
->i_mmap_lock
;
2395 spin_lock(&mapping
->i_mmap_lock
);
2397 /* Protect against endless unmapping loops */
2398 mapping
->truncate_count
++;
2399 if (unlikely(is_restart_addr(mapping
->truncate_count
))) {
2400 if (mapping
->truncate_count
== 0)
2401 reset_vma_truncate_counts(mapping
);
2402 mapping
->truncate_count
++;
2404 details
.truncate_count
= mapping
->truncate_count
;
2406 if (unlikely(!prio_tree_empty(&mapping
->i_mmap
)))
2407 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2408 if (unlikely(!list_empty(&mapping
->i_mmap_nonlinear
)))
2409 unmap_mapping_range_list(&mapping
->i_mmap_nonlinear
, &details
);
2410 spin_unlock(&mapping
->i_mmap_lock
);
2412 EXPORT_SYMBOL(unmap_mapping_range
);
2415 * vmtruncate - unmap mappings "freed" by truncate() syscall
2416 * @inode: inode of the file used
2417 * @offset: file offset to start truncating
2419 * NOTE! We have to be ready to update the memory sharing
2420 * between the file and the memory map for a potential last
2421 * incomplete page. Ugly, but necessary.
2423 int vmtruncate(struct inode
* inode
, loff_t offset
)
2425 if (inode
->i_size
< offset
) {
2426 unsigned long limit
;
2428 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
2429 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
2431 if (offset
> inode
->i_sb
->s_maxbytes
)
2433 i_size_write(inode
, offset
);
2435 struct address_space
*mapping
= inode
->i_mapping
;
2438 * truncation of in-use swapfiles is disallowed - it would
2439 * cause subsequent swapout to scribble on the now-freed
2442 if (IS_SWAPFILE(inode
))
2444 i_size_write(inode
, offset
);
2447 * unmap_mapping_range is called twice, first simply for
2448 * efficiency so that truncate_inode_pages does fewer
2449 * single-page unmaps. However after this first call, and
2450 * before truncate_inode_pages finishes, it is possible for
2451 * private pages to be COWed, which remain after
2452 * truncate_inode_pages finishes, hence the second
2453 * unmap_mapping_range call must be made for correctness.
2455 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2456 truncate_inode_pages(mapping
, offset
);
2457 unmap_mapping_range(mapping
, offset
+ PAGE_SIZE
- 1, 0, 1);
2460 if (inode
->i_op
->truncate
)
2461 inode
->i_op
->truncate(inode
);
2465 send_sig(SIGXFSZ
, current
, 0);
2469 EXPORT_SYMBOL(vmtruncate
);
2471 int vmtruncate_range(struct inode
*inode
, loff_t offset
, loff_t end
)
2473 struct address_space
*mapping
= inode
->i_mapping
;
2476 * If the underlying filesystem is not going to provide
2477 * a way to truncate a range of blocks (punch a hole) -
2478 * we should return failure right now.
2480 if (!inode
->i_op
->truncate_range
)
2483 mutex_lock(&inode
->i_mutex
);
2484 down_write(&inode
->i_alloc_sem
);
2485 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2486 truncate_inode_pages_range(mapping
, offset
, end
);
2487 unmap_mapping_range(mapping
, offset
, (end
- offset
), 1);
2488 inode
->i_op
->truncate_range(inode
, offset
, end
);
2489 up_write(&inode
->i_alloc_sem
);
2490 mutex_unlock(&inode
->i_mutex
);
2496 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2497 * but allow concurrent faults), and pte mapped but not yet locked.
2498 * We return with mmap_sem still held, but pte unmapped and unlocked.
2500 static int do_swap_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2501 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2502 unsigned int flags
, pte_t orig_pte
)
2508 struct mem_cgroup
*ptr
= NULL
;
2511 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2514 entry
= pte_to_swp_entry(orig_pte
);
2515 if (is_migration_entry(entry
)) {
2516 migration_entry_wait(mm
, pmd
, address
);
2519 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2520 page
= lookup_swap_cache(entry
);
2522 grab_swap_token(mm
); /* Contend for token _before_ read-in */
2523 page
= swapin_readahead(entry
,
2524 GFP_HIGHUSER_MOVABLE
, vma
, address
);
2527 * Back out if somebody else faulted in this pte
2528 * while we released the pte lock.
2530 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2531 if (likely(pte_same(*page_table
, orig_pte
)))
2533 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2537 /* Had to read the page from swap area: Major fault */
2538 ret
= VM_FAULT_MAJOR
;
2539 count_vm_event(PGMAJFAULT
);
2543 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2545 if (mem_cgroup_try_charge_swapin(mm
, page
, GFP_KERNEL
, &ptr
)) {
2551 * Back out if somebody else already faulted in this pte.
2553 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2554 if (unlikely(!pte_same(*page_table
, orig_pte
)))
2557 if (unlikely(!PageUptodate(page
))) {
2558 ret
= VM_FAULT_SIGBUS
;
2563 * The page isn't present yet, go ahead with the fault.
2565 * Be careful about the sequence of operations here.
2566 * To get its accounting right, reuse_swap_page() must be called
2567 * while the page is counted on swap but not yet in mapcount i.e.
2568 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2569 * must be called after the swap_free(), or it will never succeed.
2570 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2571 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2572 * in page->private. In this case, a record in swap_cgroup is silently
2573 * discarded at swap_free().
2576 inc_mm_counter(mm
, anon_rss
);
2577 pte
= mk_pte(page
, vma
->vm_page_prot
);
2578 if ((flags
& FAULT_FLAG_WRITE
) && reuse_swap_page(page
)) {
2579 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
2580 flags
&= ~FAULT_FLAG_WRITE
;
2582 flush_icache_page(vma
, page
);
2583 set_pte_at(mm
, address
, page_table
, pte
);
2584 page_add_anon_rmap(page
, vma
, address
);
2585 /* It's better to call commit-charge after rmap is established */
2586 mem_cgroup_commit_charge_swapin(page
, ptr
);
2589 if (vm_swap_full() || (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
2590 try_to_free_swap(page
);
2593 if (flags
& FAULT_FLAG_WRITE
) {
2594 ret
|= do_wp_page(mm
, vma
, address
, page_table
, pmd
, ptl
, pte
);
2595 if (ret
& VM_FAULT_ERROR
)
2596 ret
&= VM_FAULT_ERROR
;
2600 /* No need to invalidate - it was non-present before */
2601 update_mmu_cache(vma
, address
, pte
);
2603 pte_unmap_unlock(page_table
, ptl
);
2607 mem_cgroup_cancel_charge_swapin(ptr
);
2608 pte_unmap_unlock(page_table
, ptl
);
2611 page_cache_release(page
);
2616 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2617 * but allow concurrent faults), and pte mapped but not yet locked.
2618 * We return with mmap_sem still held, but pte unmapped and unlocked.
2620 static int do_anonymous_page(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2621 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2628 /* Allocate our own private page. */
2629 pte_unmap(page_table
);
2631 if (unlikely(anon_vma_prepare(vma
)))
2633 page
= alloc_zeroed_user_highpage_movable(vma
, address
);
2636 __SetPageUptodate(page
);
2638 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
))
2641 entry
= mk_pte(page
, vma
->vm_page_prot
);
2642 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2644 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2645 if (!pte_none(*page_table
))
2648 inc_mm_counter(mm
, anon_rss
);
2649 page_add_new_anon_rmap(page
, vma
, address
);
2650 set_pte_at(mm
, address
, page_table
, entry
);
2652 /* No need to invalidate - it was non-present before */
2653 update_mmu_cache(vma
, address
, entry
);
2655 pte_unmap_unlock(page_table
, ptl
);
2658 mem_cgroup_uncharge_page(page
);
2659 page_cache_release(page
);
2662 page_cache_release(page
);
2664 return VM_FAULT_OOM
;
2668 * __do_fault() tries to create a new page mapping. It aggressively
2669 * tries to share with existing pages, but makes a separate copy if
2670 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2671 * the next page fault.
2673 * As this is called only for pages that do not currently exist, we
2674 * do not need to flush old virtual caches or the TLB.
2676 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2677 * but allow concurrent faults), and pte neither mapped nor locked.
2678 * We return with mmap_sem still held, but pte unmapped and unlocked.
2680 static int __do_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2681 unsigned long address
, pmd_t
*pmd
,
2682 pgoff_t pgoff
, unsigned int flags
, pte_t orig_pte
)
2690 struct page
*dirty_page
= NULL
;
2691 struct vm_fault vmf
;
2693 int page_mkwrite
= 0;
2695 vmf
.virtual_address
= (void __user
*)(address
& PAGE_MASK
);
2700 ret
= vma
->vm_ops
->fault(vma
, &vmf
);
2701 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2705 * For consistency in subsequent calls, make the faulted page always
2708 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
2709 lock_page(vmf
.page
);
2711 VM_BUG_ON(!PageLocked(vmf
.page
));
2714 * Should we do an early C-O-W break?
2717 if (flags
& FAULT_FLAG_WRITE
) {
2718 if (!(vma
->vm_flags
& VM_SHARED
)) {
2720 if (unlikely(anon_vma_prepare(vma
))) {
2724 page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
,
2730 if (mem_cgroup_newpage_charge(page
, mm
, GFP_KERNEL
)) {
2732 page_cache_release(page
);
2737 * Don't let another task, with possibly unlocked vma,
2738 * keep the mlocked page.
2740 if (vma
->vm_flags
& VM_LOCKED
)
2741 clear_page_mlock(vmf
.page
);
2742 copy_user_highpage(page
, vmf
.page
, address
, vma
);
2743 __SetPageUptodate(page
);
2746 * If the page will be shareable, see if the backing
2747 * address space wants to know that the page is about
2748 * to become writable
2750 if (vma
->vm_ops
->page_mkwrite
) {
2754 vmf
.flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2755 tmp
= vma
->vm_ops
->page_mkwrite(vma
, &vmf
);
2757 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2759 goto unwritable_page
;
2761 if (unlikely(!(tmp
& VM_FAULT_LOCKED
))) {
2763 if (!page
->mapping
) {
2764 ret
= 0; /* retry the fault */
2766 goto unwritable_page
;
2769 VM_BUG_ON(!PageLocked(page
));
2776 page_table
= pte_offset_map_lock(mm
, pmd
, address
, &ptl
);
2779 * This silly early PAGE_DIRTY setting removes a race
2780 * due to the bad i386 page protection. But it's valid
2781 * for other architectures too.
2783 * Note that if FAULT_FLAG_WRITE is set, we either now have
2784 * an exclusive copy of the page, or this is a shared mapping,
2785 * so we can make it writable and dirty to avoid having to
2786 * handle that later.
2788 /* Only go through if we didn't race with anybody else... */
2789 if (likely(pte_same(*page_table
, orig_pte
))) {
2790 flush_icache_page(vma
, page
);
2791 entry
= mk_pte(page
, vma
->vm_page_prot
);
2792 if (flags
& FAULT_FLAG_WRITE
)
2793 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2795 inc_mm_counter(mm
, anon_rss
);
2796 page_add_new_anon_rmap(page
, vma
, address
);
2798 inc_mm_counter(mm
, file_rss
);
2799 page_add_file_rmap(page
);
2800 if (flags
& FAULT_FLAG_WRITE
) {
2802 get_page(dirty_page
);
2805 set_pte_at(mm
, address
, page_table
, entry
);
2807 /* no need to invalidate: a not-present page won't be cached */
2808 update_mmu_cache(vma
, address
, entry
);
2811 mem_cgroup_uncharge_page(page
);
2813 page_cache_release(page
);
2815 anon
= 1; /* no anon but release faulted_page */
2818 pte_unmap_unlock(page_table
, ptl
);
2822 struct address_space
*mapping
= page
->mapping
;
2824 if (set_page_dirty(dirty_page
))
2826 unlock_page(dirty_page
);
2827 put_page(dirty_page
);
2828 if (page_mkwrite
&& mapping
) {
2830 * Some device drivers do not set page.mapping but still
2833 balance_dirty_pages_ratelimited(mapping
);
2836 /* file_update_time outside page_lock */
2838 file_update_time(vma
->vm_file
);
2840 unlock_page(vmf
.page
);
2842 page_cache_release(vmf
.page
);
2848 page_cache_release(page
);
2852 static int do_linear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2853 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2854 unsigned int flags
, pte_t orig_pte
)
2856 pgoff_t pgoff
= (((address
& PAGE_MASK
)
2857 - vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
2859 pte_unmap(page_table
);
2860 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2864 * Fault of a previously existing named mapping. Repopulate the pte
2865 * from the encoded file_pte if possible. This enables swappable
2868 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2869 * but allow concurrent faults), and pte mapped but not yet locked.
2870 * We return with mmap_sem still held, but pte unmapped and unlocked.
2872 static int do_nonlinear_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2873 unsigned long address
, pte_t
*page_table
, pmd_t
*pmd
,
2874 unsigned int flags
, pte_t orig_pte
)
2878 flags
|= FAULT_FLAG_NONLINEAR
;
2880 if (!pte_unmap_same(mm
, pmd
, page_table
, orig_pte
))
2883 if (unlikely(!(vma
->vm_flags
& VM_NONLINEAR
))) {
2885 * Page table corrupted: show pte and kill process.
2887 print_bad_pte(vma
, address
, orig_pte
, NULL
);
2888 return VM_FAULT_OOM
;
2891 pgoff
= pte_to_pgoff(orig_pte
);
2892 return __do_fault(mm
, vma
, address
, pmd
, pgoff
, flags
, orig_pte
);
2896 * These routines also need to handle stuff like marking pages dirty
2897 * and/or accessed for architectures that don't do it in hardware (most
2898 * RISC architectures). The early dirtying is also good on the i386.
2900 * There is also a hook called "update_mmu_cache()" that architectures
2901 * with external mmu caches can use to update those (ie the Sparc or
2902 * PowerPC hashed page tables that act as extended TLBs).
2904 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2905 * but allow concurrent faults), and pte mapped but not yet locked.
2906 * We return with mmap_sem still held, but pte unmapped and unlocked.
2908 static inline int handle_pte_fault(struct mm_struct
*mm
,
2909 struct vm_area_struct
*vma
, unsigned long address
,
2910 pte_t
*pte
, pmd_t
*pmd
, unsigned int flags
)
2916 if (!pte_present(entry
)) {
2917 if (pte_none(entry
)) {
2919 if (likely(vma
->vm_ops
->fault
))
2920 return do_linear_fault(mm
, vma
, address
,
2921 pte
, pmd
, flags
, entry
);
2923 return do_anonymous_page(mm
, vma
, address
,
2926 if (pte_file(entry
))
2927 return do_nonlinear_fault(mm
, vma
, address
,
2928 pte
, pmd
, flags
, entry
);
2929 return do_swap_page(mm
, vma
, address
,
2930 pte
, pmd
, flags
, entry
);
2933 ptl
= pte_lockptr(mm
, pmd
);
2935 if (unlikely(!pte_same(*pte
, entry
)))
2937 if (flags
& FAULT_FLAG_WRITE
) {
2938 if (!pte_write(entry
))
2939 return do_wp_page(mm
, vma
, address
,
2940 pte
, pmd
, ptl
, entry
);
2941 entry
= pte_mkdirty(entry
);
2943 entry
= pte_mkyoung(entry
);
2944 if (ptep_set_access_flags(vma
, address
, pte
, entry
, flags
& FAULT_FLAG_WRITE
)) {
2945 update_mmu_cache(vma
, address
, entry
);
2948 * This is needed only for protection faults but the arch code
2949 * is not yet telling us if this is a protection fault or not.
2950 * This still avoids useless tlb flushes for .text page faults
2953 if (flags
& FAULT_FLAG_WRITE
)
2954 flush_tlb_page(vma
, address
);
2957 pte_unmap_unlock(pte
, ptl
);
2962 * By the time we get here, we already hold the mm semaphore
2964 int handle_mm_fault(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
2965 unsigned long address
, unsigned int flags
)
2972 __set_current_state(TASK_RUNNING
);
2974 count_vm_event(PGFAULT
);
2976 if (unlikely(is_vm_hugetlb_page(vma
)))
2977 return hugetlb_fault(mm
, vma
, address
, flags
);
2979 pgd
= pgd_offset(mm
, address
);
2980 pud
= pud_alloc(mm
, pgd
, address
);
2982 return VM_FAULT_OOM
;
2983 pmd
= pmd_alloc(mm
, pud
, address
);
2985 return VM_FAULT_OOM
;
2986 pte
= pte_alloc_map(mm
, pmd
, address
);
2988 return VM_FAULT_OOM
;
2990 return handle_pte_fault(mm
, vma
, address
, pte
, pmd
, flags
);
2993 #ifndef __PAGETABLE_PUD_FOLDED
2995 * Allocate page upper directory.
2996 * We've already handled the fast-path in-line.
2998 int __pud_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
3000 pud_t
*new = pud_alloc_one(mm
, address
);
3004 smp_wmb(); /* See comment in __pte_alloc */
3006 spin_lock(&mm
->page_table_lock
);
3007 if (pgd_present(*pgd
)) /* Another has populated it */
3010 pgd_populate(mm
, pgd
, new);
3011 spin_unlock(&mm
->page_table_lock
);
3014 #endif /* __PAGETABLE_PUD_FOLDED */
3016 #ifndef __PAGETABLE_PMD_FOLDED
3018 * Allocate page middle directory.
3019 * We've already handled the fast-path in-line.
3021 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
3023 pmd_t
*new = pmd_alloc_one(mm
, address
);
3027 smp_wmb(); /* See comment in __pte_alloc */
3029 spin_lock(&mm
->page_table_lock
);
3030 #ifndef __ARCH_HAS_4LEVEL_HACK
3031 if (pud_present(*pud
)) /* Another has populated it */
3034 pud_populate(mm
, pud
, new);
3036 if (pgd_present(*pud
)) /* Another has populated it */
3039 pgd_populate(mm
, pud
, new);
3040 #endif /* __ARCH_HAS_4LEVEL_HACK */
3041 spin_unlock(&mm
->page_table_lock
);
3044 #endif /* __PAGETABLE_PMD_FOLDED */
3046 int make_pages_present(unsigned long addr
, unsigned long end
)
3048 int ret
, len
, write
;
3049 struct vm_area_struct
* vma
;
3051 vma
= find_vma(current
->mm
, addr
);
3054 write
= (vma
->vm_flags
& VM_WRITE
) != 0;
3055 BUG_ON(addr
>= end
);
3056 BUG_ON(end
> vma
->vm_end
);
3057 len
= DIV_ROUND_UP(end
, PAGE_SIZE
) - addr
/PAGE_SIZE
;
3058 ret
= get_user_pages(current
, current
->mm
, addr
,
3059 len
, write
, 0, NULL
, NULL
);
3062 return ret
== len
? 0 : -EFAULT
;
3065 #if !defined(__HAVE_ARCH_GATE_AREA)
3067 #if defined(AT_SYSINFO_EHDR)
3068 static struct vm_area_struct gate_vma
;
3070 static int __init
gate_vma_init(void)
3072 gate_vma
.vm_mm
= NULL
;
3073 gate_vma
.vm_start
= FIXADDR_USER_START
;
3074 gate_vma
.vm_end
= FIXADDR_USER_END
;
3075 gate_vma
.vm_flags
= VM_READ
| VM_MAYREAD
| VM_EXEC
| VM_MAYEXEC
;
3076 gate_vma
.vm_page_prot
= __P101
;
3078 * Make sure the vDSO gets into every core dump.
3079 * Dumping its contents makes post-mortem fully interpretable later
3080 * without matching up the same kernel and hardware config to see
3081 * what PC values meant.
3083 gate_vma
.vm_flags
|= VM_ALWAYSDUMP
;
3086 __initcall(gate_vma_init
);
3089 struct vm_area_struct
*get_gate_vma(struct task_struct
*tsk
)
3091 #ifdef AT_SYSINFO_EHDR
3098 int in_gate_area_no_task(unsigned long addr
)
3100 #ifdef AT_SYSINFO_EHDR
3101 if ((addr
>= FIXADDR_USER_START
) && (addr
< FIXADDR_USER_END
))
3107 #endif /* __HAVE_ARCH_GATE_AREA */
3109 static int follow_pte(struct mm_struct
*mm
, unsigned long address
,
3110 pte_t
**ptepp
, spinlock_t
**ptlp
)
3117 pgd
= pgd_offset(mm
, address
);
3118 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
3121 pud
= pud_offset(pgd
, address
);
3122 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
3125 pmd
= pmd_offset(pud
, address
);
3126 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
3129 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3133 ptep
= pte_offset_map_lock(mm
, pmd
, address
, ptlp
);
3136 if (!pte_present(*ptep
))
3141 pte_unmap_unlock(ptep
, *ptlp
);
3147 * follow_pfn - look up PFN at a user virtual address
3148 * @vma: memory mapping
3149 * @address: user virtual address
3150 * @pfn: location to store found PFN
3152 * Only IO mappings and raw PFN mappings are allowed.
3154 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3156 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
3163 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3166 ret
= follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
);
3169 *pfn
= pte_pfn(*ptep
);
3170 pte_unmap_unlock(ptep
, ptl
);
3173 EXPORT_SYMBOL(follow_pfn
);
3175 #ifdef CONFIG_HAVE_IOREMAP_PROT
3176 int follow_phys(struct vm_area_struct
*vma
,
3177 unsigned long address
, unsigned int flags
,
3178 unsigned long *prot
, resource_size_t
*phys
)
3184 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
3187 if (follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
))
3191 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
3194 *prot
= pgprot_val(pte_pgprot(pte
));
3195 *phys
= (resource_size_t
)pte_pfn(pte
) << PAGE_SHIFT
;
3199 pte_unmap_unlock(ptep
, ptl
);
3204 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
3205 void *buf
, int len
, int write
)
3207 resource_size_t phys_addr
;
3208 unsigned long prot
= 0;
3209 void __iomem
*maddr
;
3210 int offset
= addr
& (PAGE_SIZE
-1);
3212 if (follow_phys(vma
, addr
, write
, &prot
, &phys_addr
))
3215 maddr
= ioremap_prot(phys_addr
, PAGE_SIZE
, prot
);
3217 memcpy_toio(maddr
+ offset
, buf
, len
);
3219 memcpy_fromio(buf
, maddr
+ offset
, len
);
3227 * Access another process' address space.
3228 * Source/target buffer must be kernel space,
3229 * Do not walk the page table directly, use get_user_pages
3231 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
3233 struct mm_struct
*mm
;
3234 struct vm_area_struct
*vma
;
3235 void *old_buf
= buf
;
3237 mm
= get_task_mm(tsk
);
3241 down_read(&mm
->mmap_sem
);
3242 /* ignore errors, just check how much was successfully transferred */
3244 int bytes
, ret
, offset
;
3246 struct page
*page
= NULL
;
3248 ret
= get_user_pages(tsk
, mm
, addr
, 1,
3249 write
, 1, &page
, &vma
);
3252 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3253 * we can access using slightly different code.
3255 #ifdef CONFIG_HAVE_IOREMAP_PROT
3256 vma
= find_vma(mm
, addr
);
3259 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
3260 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
3268 offset
= addr
& (PAGE_SIZE
-1);
3269 if (bytes
> PAGE_SIZE
-offset
)
3270 bytes
= PAGE_SIZE
-offset
;
3274 copy_to_user_page(vma
, page
, addr
,
3275 maddr
+ offset
, buf
, bytes
);
3276 set_page_dirty_lock(page
);
3278 copy_from_user_page(vma
, page
, addr
,
3279 buf
, maddr
+ offset
, bytes
);
3282 page_cache_release(page
);
3288 up_read(&mm
->mmap_sem
);
3291 return buf
- old_buf
;
3295 * Print the name of a VMA.
3297 void print_vma_addr(char *prefix
, unsigned long ip
)
3299 struct mm_struct
*mm
= current
->mm
;
3300 struct vm_area_struct
*vma
;
3303 * Do not print if we are in atomic
3304 * contexts (in exception stacks, etc.):
3306 if (preempt_count())
3309 down_read(&mm
->mmap_sem
);
3310 vma
= find_vma(mm
, ip
);
3311 if (vma
&& vma
->vm_file
) {
3312 struct file
*f
= vma
->vm_file
;
3313 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
3317 p
= d_path(&f
->f_path
, buf
, PAGE_SIZE
);
3320 s
= strrchr(p
, '/');
3323 printk("%s%s[%lx+%lx]", prefix
, p
,
3325 vma
->vm_end
- vma
->vm_start
);
3326 free_page((unsigned long)buf
);
3329 up_read(¤t
->mm
->mmap_sem
);
3332 #ifdef CONFIG_PROVE_LOCKING
3333 void might_fault(void)
3336 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3337 * holding the mmap_sem, this is safe because kernel memory doesn't
3338 * get paged out, therefore we'll never actually fault, and the
3339 * below annotations will generate false positives.
3341 if (segment_eq(get_fs(), KERNEL_DS
))
3346 * it would be nicer only to annotate paths which are not under
3347 * pagefault_disable, however that requires a larger audit and
3348 * providing helpers like get_user_atomic.
3350 if (!in_atomic() && current
->mm
)
3351 might_lock_read(¤t
->mm
->mmap_sem
);
3353 EXPORT_SYMBOL(might_fault
);