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/sched/mm.h>
44 #include <linux/sched/coredump.h>
45 #include <linux/sched/numa_balancing.h>
46 #include <linux/sched/task.h>
47 #include <linux/hugetlb.h>
48 #include <linux/mman.h>
49 #include <linux/swap.h>
50 #include <linux/highmem.h>
51 #include <linux/pagemap.h>
52 #include <linux/memremap.h>
53 #include <linux/ksm.h>
54 #include <linux/rmap.h>
55 #include <linux/export.h>
56 #include <linux/delayacct.h>
57 #include <linux/init.h>
58 #include <linux/pfn_t.h>
59 #include <linux/writeback.h>
60 #include <linux/memcontrol.h>
61 #include <linux/mmu_notifier.h>
62 #include <linux/kallsyms.h>
63 #include <linux/swapops.h>
64 #include <linux/elf.h>
65 #include <linux/gfp.h>
66 #include <linux/migrate.h>
67 #include <linux/string.h>
68 #include <linux/dma-debug.h>
69 #include <linux/debugfs.h>
70 #include <linux/userfaultfd_k.h>
71 #include <linux/dax.h>
72 #include <linux/oom.h>
75 #include <asm/mmu_context.h>
76 #include <asm/pgalloc.h>
77 #include <linux/uaccess.h>
79 #include <asm/tlbflush.h>
80 #include <asm/pgtable.h>
84 #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST)
85 #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
88 #ifndef CONFIG_NEED_MULTIPLE_NODES
89 /* use the per-pgdat data instead for discontigmem - mbligh */
90 unsigned long max_mapnr
;
91 EXPORT_SYMBOL(max_mapnr
);
94 EXPORT_SYMBOL(mem_map
);
98 * A number of key systems in x86 including ioremap() rely on the assumption
99 * that high_memory defines the upper bound on direct map memory, then end
100 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
101 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
105 EXPORT_SYMBOL(high_memory
);
108 * Randomize the address space (stacks, mmaps, brk, etc.).
110 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
111 * as ancient (libc5 based) binaries can segfault. )
113 int randomize_va_space __read_mostly
=
114 #ifdef CONFIG_COMPAT_BRK
120 static int __init
disable_randmaps(char *s
)
122 randomize_va_space
= 0;
125 __setup("norandmaps", disable_randmaps
);
127 unsigned long zero_pfn __read_mostly
;
128 EXPORT_SYMBOL(zero_pfn
);
130 unsigned long highest_memmap_pfn __read_mostly
;
133 * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
135 static int __init
init_zero_pfn(void)
137 zero_pfn
= page_to_pfn(ZERO_PAGE(0));
140 core_initcall(init_zero_pfn
);
143 #if defined(SPLIT_RSS_COUNTING)
145 void sync_mm_rss(struct mm_struct
*mm
)
149 for (i
= 0; i
< NR_MM_COUNTERS
; i
++) {
150 if (current
->rss_stat
.count
[i
]) {
151 add_mm_counter(mm
, i
, current
->rss_stat
.count
[i
]);
152 current
->rss_stat
.count
[i
] = 0;
155 current
->rss_stat
.events
= 0;
158 static void add_mm_counter_fast(struct mm_struct
*mm
, int member
, int val
)
160 struct task_struct
*task
= current
;
162 if (likely(task
->mm
== mm
))
163 task
->rss_stat
.count
[member
] += val
;
165 add_mm_counter(mm
, member
, val
);
167 #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
168 #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
170 /* sync counter once per 64 page faults */
171 #define TASK_RSS_EVENTS_THRESH (64)
172 static void check_sync_rss_stat(struct task_struct
*task
)
174 if (unlikely(task
!= current
))
176 if (unlikely(task
->rss_stat
.events
++ > TASK_RSS_EVENTS_THRESH
))
177 sync_mm_rss(task
->mm
);
179 #else /* SPLIT_RSS_COUNTING */
181 #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
182 #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
184 static void check_sync_rss_stat(struct task_struct
*task
)
188 #endif /* SPLIT_RSS_COUNTING */
190 #ifdef HAVE_GENERIC_MMU_GATHER
192 static bool tlb_next_batch(struct mmu_gather
*tlb
)
194 struct mmu_gather_batch
*batch
;
198 tlb
->active
= batch
->next
;
202 if (tlb
->batch_count
== MAX_GATHER_BATCH_COUNT
)
205 batch
= (void *)__get_free_pages(GFP_NOWAIT
| __GFP_NOWARN
, 0);
212 batch
->max
= MAX_GATHER_BATCH
;
214 tlb
->active
->next
= batch
;
220 void arch_tlb_gather_mmu(struct mmu_gather
*tlb
, struct mm_struct
*mm
,
221 unsigned long start
, unsigned long end
)
225 /* Is it from 0 to ~0? */
226 tlb
->fullmm
= !(start
| (end
+1));
227 tlb
->need_flush_all
= 0;
228 tlb
->local
.next
= NULL
;
230 tlb
->local
.max
= ARRAY_SIZE(tlb
->__pages
);
231 tlb
->active
= &tlb
->local
;
232 tlb
->batch_count
= 0;
234 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
239 __tlb_reset_range(tlb
);
242 static void tlb_flush_mmu_tlbonly(struct mmu_gather
*tlb
)
248 mmu_notifier_invalidate_range(tlb
->mm
, tlb
->start
, tlb
->end
);
249 __tlb_reset_range(tlb
);
252 static void tlb_flush_mmu_free(struct mmu_gather
*tlb
)
254 struct mmu_gather_batch
*batch
;
256 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
257 tlb_table_flush(tlb
);
259 for (batch
= &tlb
->local
; batch
&& batch
->nr
; batch
= batch
->next
) {
260 free_pages_and_swap_cache(batch
->pages
, batch
->nr
);
263 tlb
->active
= &tlb
->local
;
266 void tlb_flush_mmu(struct mmu_gather
*tlb
)
268 tlb_flush_mmu_tlbonly(tlb
);
269 tlb_flush_mmu_free(tlb
);
273 * Called at the end of the shootdown operation to free up any resources
274 * that were required.
276 void arch_tlb_finish_mmu(struct mmu_gather
*tlb
,
277 unsigned long start
, unsigned long end
, bool force
)
279 struct mmu_gather_batch
*batch
, *next
;
282 __tlb_adjust_range(tlb
, start
, end
- start
);
286 /* keep the page table cache within bounds */
289 for (batch
= tlb
->local
.next
; batch
; batch
= next
) {
291 free_pages((unsigned long)batch
, 0);
293 tlb
->local
.next
= NULL
;
297 * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
298 * handling the additional races in SMP caused by other CPUs caching valid
299 * mappings in their TLBs. Returns the number of free page slots left.
300 * When out of page slots we must call tlb_flush_mmu().
301 *returns true if the caller should flush.
303 bool __tlb_remove_page_size(struct mmu_gather
*tlb
, struct page
*page
, int page_size
)
305 struct mmu_gather_batch
*batch
;
307 VM_BUG_ON(!tlb
->end
);
308 VM_WARN_ON(tlb
->page_size
!= page_size
);
312 * Add the page and check if we are full. If so
315 batch
->pages
[batch
->nr
++] = page
;
316 if (batch
->nr
== batch
->max
) {
317 if (!tlb_next_batch(tlb
))
321 VM_BUG_ON_PAGE(batch
->nr
> batch
->max
, page
);
326 #endif /* HAVE_GENERIC_MMU_GATHER */
328 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
331 * See the comment near struct mmu_table_batch.
335 * If we want tlb_remove_table() to imply TLB invalidates.
337 static inline void tlb_table_invalidate(struct mmu_gather
*tlb
)
339 #ifdef CONFIG_HAVE_RCU_TABLE_INVALIDATE
341 * Invalidate page-table caches used by hardware walkers. Then we still
342 * need to RCU-sched wait while freeing the pages because software
343 * walkers can still be in-flight.
345 tlb_flush_mmu_tlbonly(tlb
);
349 static void tlb_remove_table_smp_sync(void *arg
)
351 /* Simply deliver the interrupt */
354 static void tlb_remove_table_one(void *table
)
357 * This isn't an RCU grace period and hence the page-tables cannot be
358 * assumed to be actually RCU-freed.
360 * It is however sufficient for software page-table walkers that rely on
361 * IRQ disabling. See the comment near struct mmu_table_batch.
363 smp_call_function(tlb_remove_table_smp_sync
, NULL
, 1);
364 __tlb_remove_table(table
);
367 static void tlb_remove_table_rcu(struct rcu_head
*head
)
369 struct mmu_table_batch
*batch
;
372 batch
= container_of(head
, struct mmu_table_batch
, rcu
);
374 for (i
= 0; i
< batch
->nr
; i
++)
375 __tlb_remove_table(batch
->tables
[i
]);
377 free_page((unsigned long)batch
);
380 void tlb_table_flush(struct mmu_gather
*tlb
)
382 struct mmu_table_batch
**batch
= &tlb
->batch
;
385 tlb_table_invalidate(tlb
);
386 call_rcu_sched(&(*batch
)->rcu
, tlb_remove_table_rcu
);
391 void tlb_remove_table(struct mmu_gather
*tlb
, void *table
)
393 struct mmu_table_batch
**batch
= &tlb
->batch
;
395 if (*batch
== NULL
) {
396 *batch
= (struct mmu_table_batch
*)__get_free_page(GFP_NOWAIT
| __GFP_NOWARN
);
397 if (*batch
== NULL
) {
398 tlb_table_invalidate(tlb
);
399 tlb_remove_table_one(table
);
405 (*batch
)->tables
[(*batch
)->nr
++] = table
;
406 if ((*batch
)->nr
== MAX_TABLE_BATCH
)
407 tlb_table_flush(tlb
);
410 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
413 * Called to initialize an (on-stack) mmu_gather structure for page-table
414 * tear-down from @mm. The @fullmm argument is used when @mm is without
415 * users and we're going to destroy the full address space (exit/execve).
417 void tlb_gather_mmu(struct mmu_gather
*tlb
, struct mm_struct
*mm
,
418 unsigned long start
, unsigned long end
)
420 arch_tlb_gather_mmu(tlb
, mm
, start
, end
);
421 inc_tlb_flush_pending(tlb
->mm
);
424 void tlb_finish_mmu(struct mmu_gather
*tlb
,
425 unsigned long start
, unsigned long end
)
428 * If there are parallel threads are doing PTE changes on same range
429 * under non-exclusive lock(e.g., mmap_sem read-side) but defer TLB
430 * flush by batching, a thread has stable TLB entry can fail to flush
431 * the TLB by observing pte_none|!pte_dirty, for example so flush TLB
432 * forcefully if we detect parallel PTE batching threads.
434 bool force
= mm_tlb_flush_nested(tlb
->mm
);
436 arch_tlb_finish_mmu(tlb
, start
, end
, force
);
437 dec_tlb_flush_pending(tlb
->mm
);
441 * Note: this doesn't free the actual pages themselves. That
442 * has been handled earlier when unmapping all the memory regions.
444 static void free_pte_range(struct mmu_gather
*tlb
, pmd_t
*pmd
,
447 pgtable_t token
= pmd_pgtable(*pmd
);
449 pte_free_tlb(tlb
, token
, addr
);
450 atomic_long_dec(&tlb
->mm
->nr_ptes
);
453 static inline void free_pmd_range(struct mmu_gather
*tlb
, pud_t
*pud
,
454 unsigned long addr
, unsigned long end
,
455 unsigned long floor
, unsigned long ceiling
)
462 pmd
= pmd_offset(pud
, addr
);
464 next
= pmd_addr_end(addr
, end
);
465 if (pmd_none_or_clear_bad(pmd
))
467 free_pte_range(tlb
, pmd
, addr
);
468 } while (pmd
++, addr
= next
, addr
!= end
);
478 if (end
- 1 > ceiling
- 1)
481 pmd
= pmd_offset(pud
, start
);
483 pmd_free_tlb(tlb
, pmd
, start
);
484 mm_dec_nr_pmds(tlb
->mm
);
487 static inline void free_pud_range(struct mmu_gather
*tlb
, p4d_t
*p4d
,
488 unsigned long addr
, unsigned long end
,
489 unsigned long floor
, unsigned long ceiling
)
496 pud
= pud_offset(p4d
, addr
);
498 next
= pud_addr_end(addr
, end
);
499 if (pud_none_or_clear_bad(pud
))
501 free_pmd_range(tlb
, pud
, addr
, next
, floor
, ceiling
);
502 } while (pud
++, addr
= next
, addr
!= end
);
512 if (end
- 1 > ceiling
- 1)
515 pud
= pud_offset(p4d
, start
);
517 pud_free_tlb(tlb
, pud
, start
);
520 static inline void free_p4d_range(struct mmu_gather
*tlb
, pgd_t
*pgd
,
521 unsigned long addr
, unsigned long end
,
522 unsigned long floor
, unsigned long ceiling
)
529 p4d
= p4d_offset(pgd
, addr
);
531 next
= p4d_addr_end(addr
, end
);
532 if (p4d_none_or_clear_bad(p4d
))
534 free_pud_range(tlb
, p4d
, addr
, next
, floor
, ceiling
);
535 } while (p4d
++, addr
= next
, addr
!= end
);
541 ceiling
&= PGDIR_MASK
;
545 if (end
- 1 > ceiling
- 1)
548 p4d
= p4d_offset(pgd
, start
);
550 p4d_free_tlb(tlb
, p4d
, start
);
554 * This function frees user-level page tables of a process.
556 void free_pgd_range(struct mmu_gather
*tlb
,
557 unsigned long addr
, unsigned long end
,
558 unsigned long floor
, unsigned long ceiling
)
564 * The next few lines have given us lots of grief...
566 * Why are we testing PMD* at this top level? Because often
567 * there will be no work to do at all, and we'd prefer not to
568 * go all the way down to the bottom just to discover that.
570 * Why all these "- 1"s? Because 0 represents both the bottom
571 * of the address space and the top of it (using -1 for the
572 * top wouldn't help much: the masks would do the wrong thing).
573 * The rule is that addr 0 and floor 0 refer to the bottom of
574 * the address space, but end 0 and ceiling 0 refer to the top
575 * Comparisons need to use "end - 1" and "ceiling - 1" (though
576 * that end 0 case should be mythical).
578 * Wherever addr is brought up or ceiling brought down, we must
579 * be careful to reject "the opposite 0" before it confuses the
580 * subsequent tests. But what about where end is brought down
581 * by PMD_SIZE below? no, end can't go down to 0 there.
583 * Whereas we round start (addr) and ceiling down, by different
584 * masks at different levels, in order to test whether a table
585 * now has no other vmas using it, so can be freed, we don't
586 * bother to round floor or end up - the tests don't need that.
600 if (end
- 1 > ceiling
- 1)
605 * We add page table cache pages with PAGE_SIZE,
606 * (see pte_free_tlb()), flush the tlb if we need
608 tlb_remove_check_page_size_change(tlb
, PAGE_SIZE
);
609 pgd
= pgd_offset(tlb
->mm
, addr
);
611 next
= pgd_addr_end(addr
, end
);
612 if (pgd_none_or_clear_bad(pgd
))
614 free_p4d_range(tlb
, pgd
, addr
, next
, floor
, ceiling
);
615 } while (pgd
++, addr
= next
, addr
!= end
);
618 void free_pgtables(struct mmu_gather
*tlb
, struct vm_area_struct
*vma
,
619 unsigned long floor
, unsigned long ceiling
)
622 struct vm_area_struct
*next
= vma
->vm_next
;
623 unsigned long addr
= vma
->vm_start
;
626 * Hide vma from rmap and truncate_pagecache before freeing
629 unlink_anon_vmas(vma
);
630 unlink_file_vma(vma
);
632 if (is_vm_hugetlb_page(vma
)) {
633 hugetlb_free_pgd_range(tlb
, addr
, vma
->vm_end
,
634 floor
, next
? next
->vm_start
: ceiling
);
637 * Optimization: gather nearby vmas into one call down
639 while (next
&& next
->vm_start
<= vma
->vm_end
+ PMD_SIZE
640 && !is_vm_hugetlb_page(next
)) {
643 unlink_anon_vmas(vma
);
644 unlink_file_vma(vma
);
646 free_pgd_range(tlb
, addr
, vma
->vm_end
,
647 floor
, next
? next
->vm_start
: ceiling
);
653 int __pte_alloc(struct mm_struct
*mm
, pmd_t
*pmd
, unsigned long address
)
656 pgtable_t
new = pte_alloc_one(mm
, address
);
661 * Ensure all pte setup (eg. pte page lock and page clearing) are
662 * visible before the pte is made visible to other CPUs by being
663 * put into page tables.
665 * The other side of the story is the pointer chasing in the page
666 * table walking code (when walking the page table without locking;
667 * ie. most of the time). Fortunately, these data accesses consist
668 * of a chain of data-dependent loads, meaning most CPUs (alpha
669 * being the notable exception) will already guarantee loads are
670 * seen in-order. See the alpha page table accessors for the
671 * smp_read_barrier_depends() barriers in page table walking code.
673 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
675 ptl
= pmd_lock(mm
, pmd
);
676 if (likely(pmd_none(*pmd
))) { /* Has another populated it ? */
677 atomic_long_inc(&mm
->nr_ptes
);
678 pmd_populate(mm
, pmd
, new);
687 int __pte_alloc_kernel(pmd_t
*pmd
, unsigned long address
)
689 pte_t
*new = pte_alloc_one_kernel(&init_mm
, address
);
693 smp_wmb(); /* See comment in __pte_alloc */
695 spin_lock(&init_mm
.page_table_lock
);
696 if (likely(pmd_none(*pmd
))) { /* Has another populated it ? */
697 pmd_populate_kernel(&init_mm
, pmd
, new);
700 spin_unlock(&init_mm
.page_table_lock
);
702 pte_free_kernel(&init_mm
, new);
706 static inline void init_rss_vec(int *rss
)
708 memset(rss
, 0, sizeof(int) * NR_MM_COUNTERS
);
711 static inline void add_mm_rss_vec(struct mm_struct
*mm
, int *rss
)
715 if (current
->mm
== mm
)
717 for (i
= 0; i
< NR_MM_COUNTERS
; i
++)
719 add_mm_counter(mm
, i
, rss
[i
]);
723 * This function is called to print an error when a bad pte
724 * is found. For example, we might have a PFN-mapped pte in
725 * a region that doesn't allow it.
727 * The calling function must still handle the error.
729 static void print_bad_pte(struct vm_area_struct
*vma
, unsigned long addr
,
730 pte_t pte
, struct page
*page
)
732 pgd_t
*pgd
= pgd_offset(vma
->vm_mm
, addr
);
733 p4d_t
*p4d
= p4d_offset(pgd
, addr
);
734 pud_t
*pud
= pud_offset(p4d
, addr
);
735 pmd_t
*pmd
= pmd_offset(pud
, addr
);
736 struct address_space
*mapping
;
738 static unsigned long resume
;
739 static unsigned long nr_shown
;
740 static unsigned long nr_unshown
;
743 * Allow a burst of 60 reports, then keep quiet for that minute;
744 * or allow a steady drip of one report per second.
746 if (nr_shown
== 60) {
747 if (time_before(jiffies
, resume
)) {
752 pr_alert("BUG: Bad page map: %lu messages suppressed\n",
759 resume
= jiffies
+ 60 * HZ
;
761 mapping
= vma
->vm_file
? vma
->vm_file
->f_mapping
: NULL
;
762 index
= linear_page_index(vma
, addr
);
764 pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
766 (long long)pte_val(pte
), (long long)pmd_val(*pmd
));
768 dump_page(page
, "bad pte");
769 pr_alert("addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
770 (void *)addr
, vma
->vm_flags
, vma
->anon_vma
, mapping
, index
);
772 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
774 pr_alert("file:%pD fault:%pf mmap:%pf readpage:%pf\n",
776 vma
->vm_ops
? vma
->vm_ops
->fault
: NULL
,
777 vma
->vm_file
? vma
->vm_file
->f_op
->mmap
: NULL
,
778 mapping
? mapping
->a_ops
->readpage
: NULL
);
780 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
784 * vm_normal_page -- This function gets the "struct page" associated with a pte.
786 * "Special" mappings do not wish to be associated with a "struct page" (either
787 * it doesn't exist, or it exists but they don't want to touch it). In this
788 * case, NULL is returned here. "Normal" mappings do have a struct page.
790 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
791 * pte bit, in which case this function is trivial. Secondly, an architecture
792 * may not have a spare pte bit, which requires a more complicated scheme,
795 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
796 * special mapping (even if there are underlying and valid "struct pages").
797 * COWed pages of a VM_PFNMAP are always normal.
799 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
800 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
801 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
802 * mapping will always honor the rule
804 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
806 * And for normal mappings this is false.
808 * This restricts such mappings to be a linear translation from virtual address
809 * to pfn. To get around this restriction, we allow arbitrary mappings so long
810 * as the vma is not a COW mapping; in that case, we know that all ptes are
811 * special (because none can have been COWed).
814 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
816 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
817 * page" backing, however the difference is that _all_ pages with a struct
818 * page (that is, those where pfn_valid is true) are refcounted and considered
819 * normal pages by the VM. The disadvantage is that pages are refcounted
820 * (which can be slower and simply not an option for some PFNMAP users). The
821 * advantage is that we don't have to follow the strict linearity rule of
822 * PFNMAP mappings in order to support COWable mappings.
825 #ifdef __HAVE_ARCH_PTE_SPECIAL
826 # define HAVE_PTE_SPECIAL 1
828 # define HAVE_PTE_SPECIAL 0
830 struct page
*_vm_normal_page(struct vm_area_struct
*vma
, unsigned long addr
,
831 pte_t pte
, bool with_public_device
)
833 unsigned long pfn
= pte_pfn(pte
);
835 if (HAVE_PTE_SPECIAL
) {
836 if (likely(!pte_special(pte
)))
838 if (vma
->vm_ops
&& vma
->vm_ops
->find_special_page
)
839 return vma
->vm_ops
->find_special_page(vma
, addr
);
840 if (vma
->vm_flags
& (VM_PFNMAP
| VM_MIXEDMAP
))
842 if (is_zero_pfn(pfn
))
846 * Device public pages are special pages (they are ZONE_DEVICE
847 * pages but different from persistent memory). They behave
848 * allmost like normal pages. The difference is that they are
849 * not on the lru and thus should never be involve with any-
850 * thing that involve lru manipulation (mlock, numa balancing,
853 * This is why we still want to return NULL for such page from
854 * vm_normal_page() so that we do not have to special case all
855 * call site of vm_normal_page().
857 if (likely(pfn
<= highest_memmap_pfn
)) {
858 struct page
*page
= pfn_to_page(pfn
);
860 if (is_device_public_page(page
)) {
861 if (with_public_device
)
866 print_bad_pte(vma
, addr
, pte
, NULL
);
870 /* !HAVE_PTE_SPECIAL case follows: */
872 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
873 if (vma
->vm_flags
& VM_MIXEDMAP
) {
879 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
880 if (pfn
== vma
->vm_pgoff
+ off
)
882 if (!is_cow_mapping(vma
->vm_flags
))
887 if (is_zero_pfn(pfn
))
890 if (unlikely(pfn
> highest_memmap_pfn
)) {
891 print_bad_pte(vma
, addr
, pte
, NULL
);
896 * NOTE! We still have PageReserved() pages in the page tables.
897 * eg. VDSO mappings can cause them to exist.
900 return pfn_to_page(pfn
);
903 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
904 struct page
*vm_normal_page_pmd(struct vm_area_struct
*vma
, unsigned long addr
,
907 unsigned long pfn
= pmd_pfn(pmd
);
910 * There is no pmd_special() but there may be special pmds, e.g.
911 * in a direct-access (dax) mapping, so let's just replicate the
912 * !HAVE_PTE_SPECIAL case from vm_normal_page() here.
914 if (unlikely(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
))) {
915 if (vma
->vm_flags
& VM_MIXEDMAP
) {
921 off
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
922 if (pfn
== vma
->vm_pgoff
+ off
)
924 if (!is_cow_mapping(vma
->vm_flags
))
929 if (is_zero_pfn(pfn
))
931 if (unlikely(pfn
> highest_memmap_pfn
))
935 * NOTE! We still have PageReserved() pages in the page tables.
936 * eg. VDSO mappings can cause them to exist.
939 return pfn_to_page(pfn
);
944 * copy one vm_area from one task to the other. Assumes the page tables
945 * already present in the new task to be cleared in the whole range
946 * covered by this vma.
949 static inline unsigned long
950 copy_one_pte(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
951 pte_t
*dst_pte
, pte_t
*src_pte
, struct vm_area_struct
*vma
,
952 unsigned long addr
, int *rss
)
954 unsigned long vm_flags
= vma
->vm_flags
;
955 pte_t pte
= *src_pte
;
958 /* pte contains position in swap or file, so copy. */
959 if (unlikely(!pte_present(pte
))) {
960 swp_entry_t entry
= pte_to_swp_entry(pte
);
962 if (likely(!non_swap_entry(entry
))) {
963 if (swap_duplicate(entry
) < 0)
966 /* make sure dst_mm is on swapoff's mmlist. */
967 if (unlikely(list_empty(&dst_mm
->mmlist
))) {
968 spin_lock(&mmlist_lock
);
969 if (list_empty(&dst_mm
->mmlist
))
970 list_add(&dst_mm
->mmlist
,
972 spin_unlock(&mmlist_lock
);
975 } else if (is_migration_entry(entry
)) {
976 page
= migration_entry_to_page(entry
);
978 rss
[mm_counter(page
)]++;
980 if (is_write_migration_entry(entry
) &&
981 is_cow_mapping(vm_flags
)) {
983 * COW mappings require pages in both
984 * parent and child to be set to read.
986 make_migration_entry_read(&entry
);
987 pte
= swp_entry_to_pte(entry
);
988 if (pte_swp_soft_dirty(*src_pte
))
989 pte
= pte_swp_mksoft_dirty(pte
);
990 set_pte_at(src_mm
, addr
, src_pte
, pte
);
992 } else if (is_device_private_entry(entry
)) {
993 page
= device_private_entry_to_page(entry
);
996 * Update rss count even for unaddressable pages, as
997 * they should treated just like normal pages in this
1000 * We will likely want to have some new rss counters
1001 * for unaddressable pages, at some point. But for now
1002 * keep things as they are.
1005 rss
[mm_counter(page
)]++;
1006 page_dup_rmap(page
, false);
1009 * We do not preserve soft-dirty information, because so
1010 * far, checkpoint/restore is the only feature that
1011 * requires that. And checkpoint/restore does not work
1012 * when a device driver is involved (you cannot easily
1013 * save and restore device driver state).
1015 if (is_write_device_private_entry(entry
) &&
1016 is_cow_mapping(vm_flags
)) {
1017 make_device_private_entry_read(&entry
);
1018 pte
= swp_entry_to_pte(entry
);
1019 set_pte_at(src_mm
, addr
, src_pte
, pte
);
1026 * If it's a COW mapping, write protect it both
1027 * in the parent and the child
1029 if (is_cow_mapping(vm_flags
)) {
1030 ptep_set_wrprotect(src_mm
, addr
, src_pte
);
1031 pte
= pte_wrprotect(pte
);
1035 * If it's a shared mapping, mark it clean in
1038 if (vm_flags
& VM_SHARED
)
1039 pte
= pte_mkclean(pte
);
1040 pte
= pte_mkold(pte
);
1042 page
= vm_normal_page(vma
, addr
, pte
);
1045 page_dup_rmap(page
, false);
1046 rss
[mm_counter(page
)]++;
1047 } else if (pte_devmap(pte
)) {
1048 page
= pte_page(pte
);
1051 * Cache coherent device memory behave like regular page and
1052 * not like persistent memory page. For more informations see
1053 * MEMORY_DEVICE_CACHE_COHERENT in memory_hotplug.h
1055 if (is_device_public_page(page
)) {
1057 page_dup_rmap(page
, false);
1058 rss
[mm_counter(page
)]++;
1063 set_pte_at(dst_mm
, addr
, dst_pte
, pte
);
1067 static int copy_pte_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
1068 pmd_t
*dst_pmd
, pmd_t
*src_pmd
, struct vm_area_struct
*vma
,
1069 unsigned long addr
, unsigned long end
)
1071 pte_t
*orig_src_pte
, *orig_dst_pte
;
1072 pte_t
*src_pte
, *dst_pte
;
1073 spinlock_t
*src_ptl
, *dst_ptl
;
1075 int rss
[NR_MM_COUNTERS
];
1076 swp_entry_t entry
= (swp_entry_t
){0};
1081 dst_pte
= pte_alloc_map_lock(dst_mm
, dst_pmd
, addr
, &dst_ptl
);
1084 src_pte
= pte_offset_map(src_pmd
, addr
);
1085 src_ptl
= pte_lockptr(src_mm
, src_pmd
);
1086 spin_lock_nested(src_ptl
, SINGLE_DEPTH_NESTING
);
1087 orig_src_pte
= src_pte
;
1088 orig_dst_pte
= dst_pte
;
1089 arch_enter_lazy_mmu_mode();
1093 * We are holding two locks at this point - either of them
1094 * could generate latencies in another task on another CPU.
1096 if (progress
>= 32) {
1098 if (need_resched() ||
1099 spin_needbreak(src_ptl
) || spin_needbreak(dst_ptl
))
1102 if (pte_none(*src_pte
)) {
1106 entry
.val
= copy_one_pte(dst_mm
, src_mm
, dst_pte
, src_pte
,
1111 } while (dst_pte
++, src_pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1113 arch_leave_lazy_mmu_mode();
1114 spin_unlock(src_ptl
);
1115 pte_unmap(orig_src_pte
);
1116 add_mm_rss_vec(dst_mm
, rss
);
1117 pte_unmap_unlock(orig_dst_pte
, dst_ptl
);
1121 if (add_swap_count_continuation(entry
, GFP_KERNEL
) < 0)
1130 static inline int copy_pmd_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
1131 pud_t
*dst_pud
, pud_t
*src_pud
, struct vm_area_struct
*vma
,
1132 unsigned long addr
, unsigned long end
)
1134 pmd_t
*src_pmd
, *dst_pmd
;
1137 dst_pmd
= pmd_alloc(dst_mm
, dst_pud
, addr
);
1140 src_pmd
= pmd_offset(src_pud
, addr
);
1142 next
= pmd_addr_end(addr
, end
);
1143 if (is_swap_pmd(*src_pmd
) || pmd_trans_huge(*src_pmd
)
1144 || pmd_devmap(*src_pmd
)) {
1146 VM_BUG_ON_VMA(next
-addr
!= HPAGE_PMD_SIZE
, vma
);
1147 err
= copy_huge_pmd(dst_mm
, src_mm
,
1148 dst_pmd
, src_pmd
, addr
, vma
);
1155 if (pmd_none_or_clear_bad(src_pmd
))
1157 if (copy_pte_range(dst_mm
, src_mm
, dst_pmd
, src_pmd
,
1160 } while (dst_pmd
++, src_pmd
++, addr
= next
, addr
!= end
);
1164 static inline int copy_pud_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
1165 p4d_t
*dst_p4d
, p4d_t
*src_p4d
, struct vm_area_struct
*vma
,
1166 unsigned long addr
, unsigned long end
)
1168 pud_t
*src_pud
, *dst_pud
;
1171 dst_pud
= pud_alloc(dst_mm
, dst_p4d
, addr
);
1174 src_pud
= pud_offset(src_p4d
, addr
);
1176 next
= pud_addr_end(addr
, end
);
1177 if (pud_trans_huge(*src_pud
) || pud_devmap(*src_pud
)) {
1180 VM_BUG_ON_VMA(next
-addr
!= HPAGE_PUD_SIZE
, vma
);
1181 err
= copy_huge_pud(dst_mm
, src_mm
,
1182 dst_pud
, src_pud
, addr
, vma
);
1189 if (pud_none_or_clear_bad(src_pud
))
1191 if (copy_pmd_range(dst_mm
, src_mm
, dst_pud
, src_pud
,
1194 } while (dst_pud
++, src_pud
++, addr
= next
, addr
!= end
);
1198 static inline int copy_p4d_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
1199 pgd_t
*dst_pgd
, pgd_t
*src_pgd
, struct vm_area_struct
*vma
,
1200 unsigned long addr
, unsigned long end
)
1202 p4d_t
*src_p4d
, *dst_p4d
;
1205 dst_p4d
= p4d_alloc(dst_mm
, dst_pgd
, addr
);
1208 src_p4d
= p4d_offset(src_pgd
, addr
);
1210 next
= p4d_addr_end(addr
, end
);
1211 if (p4d_none_or_clear_bad(src_p4d
))
1213 if (copy_pud_range(dst_mm
, src_mm
, dst_p4d
, src_p4d
,
1216 } while (dst_p4d
++, src_p4d
++, addr
= next
, addr
!= end
);
1220 int copy_page_range(struct mm_struct
*dst_mm
, struct mm_struct
*src_mm
,
1221 struct vm_area_struct
*vma
)
1223 pgd_t
*src_pgd
, *dst_pgd
;
1225 unsigned long addr
= vma
->vm_start
;
1226 unsigned long end
= vma
->vm_end
;
1227 unsigned long mmun_start
; /* For mmu_notifiers */
1228 unsigned long mmun_end
; /* For mmu_notifiers */
1233 * Don't copy ptes where a page fault will fill them correctly.
1234 * Fork becomes much lighter when there are big shared or private
1235 * readonly mappings. The tradeoff is that copy_page_range is more
1236 * efficient than faulting.
1238 if (!(vma
->vm_flags
& (VM_HUGETLB
| VM_PFNMAP
| VM_MIXEDMAP
)) &&
1242 if (is_vm_hugetlb_page(vma
))
1243 return copy_hugetlb_page_range(dst_mm
, src_mm
, vma
);
1245 if (unlikely(vma
->vm_flags
& VM_PFNMAP
)) {
1247 * We do not free on error cases below as remove_vma
1248 * gets called on error from higher level routine
1250 ret
= track_pfn_copy(vma
);
1256 * We need to invalidate the secondary MMU mappings only when
1257 * there could be a permission downgrade on the ptes of the
1258 * parent mm. And a permission downgrade will only happen if
1259 * is_cow_mapping() returns true.
1261 is_cow
= is_cow_mapping(vma
->vm_flags
);
1265 mmu_notifier_invalidate_range_start(src_mm
, mmun_start
,
1269 dst_pgd
= pgd_offset(dst_mm
, addr
);
1270 src_pgd
= pgd_offset(src_mm
, addr
);
1272 next
= pgd_addr_end(addr
, end
);
1273 if (pgd_none_or_clear_bad(src_pgd
))
1275 if (unlikely(copy_p4d_range(dst_mm
, src_mm
, dst_pgd
, src_pgd
,
1276 vma
, addr
, next
))) {
1280 } while (dst_pgd
++, src_pgd
++, addr
= next
, addr
!= end
);
1283 mmu_notifier_invalidate_range_end(src_mm
, mmun_start
, mmun_end
);
1287 static unsigned long zap_pte_range(struct mmu_gather
*tlb
,
1288 struct vm_area_struct
*vma
, pmd_t
*pmd
,
1289 unsigned long addr
, unsigned long end
,
1290 struct zap_details
*details
)
1292 struct mm_struct
*mm
= tlb
->mm
;
1293 int force_flush
= 0;
1294 int rss
[NR_MM_COUNTERS
];
1300 tlb_remove_check_page_size_change(tlb
, PAGE_SIZE
);
1303 start_pte
= pte_offset_map_lock(mm
, pmd
, addr
, &ptl
);
1305 flush_tlb_batched_pending(mm
);
1306 arch_enter_lazy_mmu_mode();
1309 if (pte_none(ptent
))
1312 if (pte_present(ptent
)) {
1315 page
= _vm_normal_page(vma
, addr
, ptent
, true);
1316 if (unlikely(details
) && page
) {
1318 * unmap_shared_mapping_pages() wants to
1319 * invalidate cache without truncating:
1320 * unmap shared but keep private pages.
1322 if (details
->check_mapping
&&
1323 details
->check_mapping
!= page_rmapping(page
))
1326 ptent
= ptep_get_and_clear_full(mm
, addr
, pte
,
1328 tlb_remove_tlb_entry(tlb
, pte
, addr
);
1329 if (unlikely(!page
))
1332 if (!PageAnon(page
)) {
1333 if (pte_dirty(ptent
)) {
1335 set_page_dirty(page
);
1337 if (pte_young(ptent
) &&
1338 likely(!(vma
->vm_flags
& VM_SEQ_READ
)))
1339 mark_page_accessed(page
);
1341 rss
[mm_counter(page
)]--;
1342 page_remove_rmap(page
, false);
1343 if (unlikely(page_mapcount(page
) < 0))
1344 print_bad_pte(vma
, addr
, ptent
, page
);
1345 if (unlikely(__tlb_remove_page(tlb
, page
))) {
1353 entry
= pte_to_swp_entry(ptent
);
1354 if (non_swap_entry(entry
) && is_device_private_entry(entry
)) {
1355 struct page
*page
= device_private_entry_to_page(entry
);
1357 if (unlikely(details
&& details
->check_mapping
)) {
1359 * unmap_shared_mapping_pages() wants to
1360 * invalidate cache without truncating:
1361 * unmap shared but keep private pages.
1363 if (details
->check_mapping
!=
1364 page_rmapping(page
))
1368 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
1369 rss
[mm_counter(page
)]--;
1370 page_remove_rmap(page
, false);
1375 /* If details->check_mapping, we leave swap entries. */
1376 if (unlikely(details
))
1379 entry
= pte_to_swp_entry(ptent
);
1380 if (!non_swap_entry(entry
))
1382 else if (is_migration_entry(entry
)) {
1385 page
= migration_entry_to_page(entry
);
1386 rss
[mm_counter(page
)]--;
1388 if (unlikely(!free_swap_and_cache(entry
)))
1389 print_bad_pte(vma
, addr
, ptent
, NULL
);
1390 pte_clear_not_present_full(mm
, addr
, pte
, tlb
->fullmm
);
1391 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1393 add_mm_rss_vec(mm
, rss
);
1394 arch_leave_lazy_mmu_mode();
1396 /* Do the actual TLB flush before dropping ptl */
1398 tlb_flush_mmu_tlbonly(tlb
);
1399 pte_unmap_unlock(start_pte
, ptl
);
1402 * If we forced a TLB flush (either due to running out of
1403 * batch buffers or because we needed to flush dirty TLB
1404 * entries before releasing the ptl), free the batched
1405 * memory too. Restart if we didn't do everything.
1409 tlb_flush_mmu_free(tlb
);
1417 static inline unsigned long zap_pmd_range(struct mmu_gather
*tlb
,
1418 struct vm_area_struct
*vma
, pud_t
*pud
,
1419 unsigned long addr
, unsigned long end
,
1420 struct zap_details
*details
)
1425 pmd
= pmd_offset(pud
, addr
);
1427 next
= pmd_addr_end(addr
, end
);
1428 if (is_swap_pmd(*pmd
) || pmd_trans_huge(*pmd
) || pmd_devmap(*pmd
)) {
1429 if (next
- addr
!= HPAGE_PMD_SIZE
)
1430 __split_huge_pmd(vma
, pmd
, addr
, false, NULL
);
1431 else if (zap_huge_pmd(tlb
, vma
, pmd
, addr
))
1436 * Here there can be other concurrent MADV_DONTNEED or
1437 * trans huge page faults running, and if the pmd is
1438 * none or trans huge it can change under us. This is
1439 * because MADV_DONTNEED holds the mmap_sem in read
1442 if (pmd_none_or_trans_huge_or_clear_bad(pmd
))
1444 next
= zap_pte_range(tlb
, vma
, pmd
, addr
, next
, details
);
1447 } while (pmd
++, addr
= next
, addr
!= end
);
1452 static inline unsigned long zap_pud_range(struct mmu_gather
*tlb
,
1453 struct vm_area_struct
*vma
, p4d_t
*p4d
,
1454 unsigned long addr
, unsigned long end
,
1455 struct zap_details
*details
)
1460 pud
= pud_offset(p4d
, addr
);
1462 next
= pud_addr_end(addr
, end
);
1463 if (pud_trans_huge(*pud
) || pud_devmap(*pud
)) {
1464 if (next
- addr
!= HPAGE_PUD_SIZE
) {
1465 VM_BUG_ON_VMA(!rwsem_is_locked(&tlb
->mm
->mmap_sem
), vma
);
1466 split_huge_pud(vma
, pud
, addr
);
1467 } else if (zap_huge_pud(tlb
, vma
, pud
, addr
))
1471 if (pud_none_or_clear_bad(pud
))
1473 next
= zap_pmd_range(tlb
, vma
, pud
, addr
, next
, details
);
1476 } while (pud
++, addr
= next
, addr
!= end
);
1481 static inline unsigned long zap_p4d_range(struct mmu_gather
*tlb
,
1482 struct vm_area_struct
*vma
, pgd_t
*pgd
,
1483 unsigned long addr
, unsigned long end
,
1484 struct zap_details
*details
)
1489 p4d
= p4d_offset(pgd
, addr
);
1491 next
= p4d_addr_end(addr
, end
);
1492 if (p4d_none_or_clear_bad(p4d
))
1494 next
= zap_pud_range(tlb
, vma
, p4d
, addr
, next
, details
);
1495 } while (p4d
++, addr
= next
, addr
!= end
);
1500 void unmap_page_range(struct mmu_gather
*tlb
,
1501 struct vm_area_struct
*vma
,
1502 unsigned long addr
, unsigned long end
,
1503 struct zap_details
*details
)
1508 BUG_ON(addr
>= end
);
1509 tlb_start_vma(tlb
, vma
);
1510 pgd
= pgd_offset(vma
->vm_mm
, addr
);
1512 next
= pgd_addr_end(addr
, end
);
1513 if (pgd_none_or_clear_bad(pgd
))
1515 next
= zap_p4d_range(tlb
, vma
, pgd
, addr
, next
, details
);
1516 } while (pgd
++, addr
= next
, addr
!= end
);
1517 tlb_end_vma(tlb
, vma
);
1521 static void unmap_single_vma(struct mmu_gather
*tlb
,
1522 struct vm_area_struct
*vma
, unsigned long start_addr
,
1523 unsigned long end_addr
,
1524 struct zap_details
*details
)
1526 unsigned long start
= max(vma
->vm_start
, start_addr
);
1529 if (start
>= vma
->vm_end
)
1531 end
= min(vma
->vm_end
, end_addr
);
1532 if (end
<= vma
->vm_start
)
1536 uprobe_munmap(vma
, start
, end
);
1538 if (unlikely(vma
->vm_flags
& VM_PFNMAP
))
1539 untrack_pfn(vma
, 0, 0);
1542 if (unlikely(is_vm_hugetlb_page(vma
))) {
1544 * It is undesirable to test vma->vm_file as it
1545 * should be non-null for valid hugetlb area.
1546 * However, vm_file will be NULL in the error
1547 * cleanup path of mmap_region. When
1548 * hugetlbfs ->mmap method fails,
1549 * mmap_region() nullifies vma->vm_file
1550 * before calling this function to clean up.
1551 * Since no pte has actually been setup, it is
1552 * safe to do nothing in this case.
1555 i_mmap_lock_write(vma
->vm_file
->f_mapping
);
1556 __unmap_hugepage_range_final(tlb
, vma
, start
, end
, NULL
);
1557 i_mmap_unlock_write(vma
->vm_file
->f_mapping
);
1560 unmap_page_range(tlb
, vma
, start
, end
, details
);
1565 * unmap_vmas - unmap a range of memory covered by a list of vma's
1566 * @tlb: address of the caller's struct mmu_gather
1567 * @vma: the starting vma
1568 * @start_addr: virtual address at which to start unmapping
1569 * @end_addr: virtual address at which to end unmapping
1571 * Unmap all pages in the vma list.
1573 * Only addresses between `start' and `end' will be unmapped.
1575 * The VMA list must be sorted in ascending virtual address order.
1577 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1578 * range after unmap_vmas() returns. So the only responsibility here is to
1579 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1580 * drops the lock and schedules.
1582 void unmap_vmas(struct mmu_gather
*tlb
,
1583 struct vm_area_struct
*vma
, unsigned long start_addr
,
1584 unsigned long end_addr
)
1586 struct mm_struct
*mm
= vma
->vm_mm
;
1588 mmu_notifier_invalidate_range_start(mm
, start_addr
, end_addr
);
1589 for ( ; vma
&& vma
->vm_start
< end_addr
; vma
= vma
->vm_next
)
1590 unmap_single_vma(tlb
, vma
, start_addr
, end_addr
, NULL
);
1591 mmu_notifier_invalidate_range_end(mm
, start_addr
, end_addr
);
1595 * zap_page_range - remove user pages in a given range
1596 * @vma: vm_area_struct holding the applicable pages
1597 * @start: starting address of pages to zap
1598 * @size: number of bytes to zap
1600 * Caller must protect the VMA list
1602 void zap_page_range(struct vm_area_struct
*vma
, unsigned long start
,
1605 struct mm_struct
*mm
= vma
->vm_mm
;
1606 struct mmu_gather tlb
;
1607 unsigned long end
= start
+ size
;
1610 tlb_gather_mmu(&tlb
, mm
, start
, end
);
1611 update_hiwater_rss(mm
);
1612 mmu_notifier_invalidate_range_start(mm
, start
, end
);
1613 for ( ; vma
&& vma
->vm_start
< end
; vma
= vma
->vm_next
) {
1614 unmap_single_vma(&tlb
, vma
, start
, end
, NULL
);
1617 * zap_page_range does not specify whether mmap_sem should be
1618 * held for read or write. That allows parallel zap_page_range
1619 * operations to unmap a PTE and defer a flush meaning that
1620 * this call observes pte_none and fails to flush the TLB.
1621 * Rather than adding a complex API, ensure that no stale
1622 * TLB entries exist when this call returns.
1624 flush_tlb_range(vma
, start
, end
);
1627 mmu_notifier_invalidate_range_end(mm
, start
, end
);
1628 tlb_finish_mmu(&tlb
, start
, end
);
1632 * zap_page_range_single - remove user pages in a given range
1633 * @vma: vm_area_struct holding the applicable pages
1634 * @address: starting address of pages to zap
1635 * @size: number of bytes to zap
1636 * @details: details of shared cache invalidation
1638 * The range must fit into one VMA.
1640 static void zap_page_range_single(struct vm_area_struct
*vma
, unsigned long address
,
1641 unsigned long size
, struct zap_details
*details
)
1643 struct mm_struct
*mm
= vma
->vm_mm
;
1644 struct mmu_gather tlb
;
1645 unsigned long end
= address
+ size
;
1648 tlb_gather_mmu(&tlb
, mm
, address
, end
);
1649 update_hiwater_rss(mm
);
1650 mmu_notifier_invalidate_range_start(mm
, address
, end
);
1651 unmap_single_vma(&tlb
, vma
, address
, end
, details
);
1652 mmu_notifier_invalidate_range_end(mm
, address
, end
);
1653 tlb_finish_mmu(&tlb
, address
, end
);
1657 * zap_vma_ptes - remove ptes mapping the vma
1658 * @vma: vm_area_struct holding ptes to be zapped
1659 * @address: starting address of pages to zap
1660 * @size: number of bytes to zap
1662 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1664 * The entire address range must be fully contained within the vma.
1666 * Returns 0 if successful.
1668 int zap_vma_ptes(struct vm_area_struct
*vma
, unsigned long address
,
1671 if (address
< vma
->vm_start
|| address
+ size
> vma
->vm_end
||
1672 !(vma
->vm_flags
& VM_PFNMAP
))
1674 zap_page_range_single(vma
, address
, size
, NULL
);
1677 EXPORT_SYMBOL_GPL(zap_vma_ptes
);
1679 pte_t
*__get_locked_pte(struct mm_struct
*mm
, unsigned long addr
,
1687 pgd
= pgd_offset(mm
, addr
);
1688 p4d
= p4d_alloc(mm
, pgd
, addr
);
1691 pud
= pud_alloc(mm
, p4d
, addr
);
1694 pmd
= pmd_alloc(mm
, pud
, addr
);
1698 VM_BUG_ON(pmd_trans_huge(*pmd
));
1699 return pte_alloc_map_lock(mm
, pmd
, addr
, ptl
);
1703 * This is the old fallback for page remapping.
1705 * For historical reasons, it only allows reserved pages. Only
1706 * old drivers should use this, and they needed to mark their
1707 * pages reserved for the old functions anyway.
1709 static int insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1710 struct page
*page
, pgprot_t prot
)
1712 struct mm_struct
*mm
= vma
->vm_mm
;
1721 flush_dcache_page(page
);
1722 pte
= get_locked_pte(mm
, addr
, &ptl
);
1726 if (!pte_none(*pte
))
1729 /* Ok, finally just insert the thing.. */
1731 inc_mm_counter_fast(mm
, mm_counter_file(page
));
1732 page_add_file_rmap(page
, false);
1733 set_pte_at(mm
, addr
, pte
, mk_pte(page
, prot
));
1736 pte_unmap_unlock(pte
, ptl
);
1739 pte_unmap_unlock(pte
, ptl
);
1745 * vm_insert_page - insert single page into user vma
1746 * @vma: user vma to map to
1747 * @addr: target user address of this page
1748 * @page: source kernel page
1750 * This allows drivers to insert individual pages they've allocated
1753 * The page has to be a nice clean _individual_ kernel allocation.
1754 * If you allocate a compound page, you need to have marked it as
1755 * such (__GFP_COMP), or manually just split the page up yourself
1756 * (see split_page()).
1758 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1759 * took an arbitrary page protection parameter. This doesn't allow
1760 * that. Your vma protection will have to be set up correctly, which
1761 * means that if you want a shared writable mapping, you'd better
1762 * ask for a shared writable mapping!
1764 * The page does not need to be reserved.
1766 * Usually this function is called from f_op->mmap() handler
1767 * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
1768 * Caller must set VM_MIXEDMAP on vma if it wants to call this
1769 * function from other places, for example from page-fault handler.
1771 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
1774 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1776 if (!page_count(page
))
1778 if (!(vma
->vm_flags
& VM_MIXEDMAP
)) {
1779 BUG_ON(down_read_trylock(&vma
->vm_mm
->mmap_sem
));
1780 BUG_ON(vma
->vm_flags
& VM_PFNMAP
);
1781 vma
->vm_flags
|= VM_MIXEDMAP
;
1783 return insert_page(vma
, addr
, page
, vma
->vm_page_prot
);
1785 EXPORT_SYMBOL(vm_insert_page
);
1787 static int insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1788 pfn_t pfn
, pgprot_t prot
, bool mkwrite
)
1790 struct mm_struct
*mm
= vma
->vm_mm
;
1796 pte
= get_locked_pte(mm
, addr
, &ptl
);
1800 if (!pte_none(*pte
)) {
1803 * For read faults on private mappings the PFN passed
1804 * in may not match the PFN we have mapped if the
1805 * mapped PFN is a writeable COW page. In the mkwrite
1806 * case we are creating a writable PTE for a shared
1807 * mapping and we expect the PFNs to match.
1809 if (WARN_ON_ONCE(pte_pfn(*pte
) != pfn_t_to_pfn(pfn
)))
1817 /* Ok, finally just insert the thing.. */
1818 if (pfn_t_devmap(pfn
))
1819 entry
= pte_mkdevmap(pfn_t_pte(pfn
, prot
));
1821 entry
= pte_mkspecial(pfn_t_pte(pfn
, prot
));
1825 entry
= pte_mkyoung(entry
);
1826 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
1829 set_pte_at(mm
, addr
, pte
, entry
);
1830 update_mmu_cache(vma
, addr
, pte
); /* XXX: why not for insert_page? */
1834 pte_unmap_unlock(pte
, ptl
);
1840 * vm_insert_pfn - insert single pfn into user vma
1841 * @vma: user vma to map to
1842 * @addr: target user address of this page
1843 * @pfn: source kernel pfn
1845 * Similar to vm_insert_page, this allows drivers to insert individual pages
1846 * they've allocated into a user vma. Same comments apply.
1848 * This function should only be called from a vm_ops->fault handler, and
1849 * in that case the handler should return NULL.
1851 * vma cannot be a COW mapping.
1853 * As this is called only for pages that do not currently exist, we
1854 * do not need to flush old virtual caches or the TLB.
1856 int vm_insert_pfn(struct vm_area_struct
*vma
, unsigned long addr
,
1859 return vm_insert_pfn_prot(vma
, addr
, pfn
, vma
->vm_page_prot
);
1861 EXPORT_SYMBOL(vm_insert_pfn
);
1864 * vm_insert_pfn_prot - insert single pfn into user vma with specified pgprot
1865 * @vma: user vma to map to
1866 * @addr: target user address of this page
1867 * @pfn: source kernel pfn
1868 * @pgprot: pgprot flags for the inserted page
1870 * This is exactly like vm_insert_pfn, except that it allows drivers to
1871 * to override pgprot on a per-page basis.
1873 * This only makes sense for IO mappings, and it makes no sense for
1874 * cow mappings. In general, using multiple vmas is preferable;
1875 * vm_insert_pfn_prot should only be used if using multiple VMAs is
1878 int vm_insert_pfn_prot(struct vm_area_struct
*vma
, unsigned long addr
,
1879 unsigned long pfn
, pgprot_t pgprot
)
1883 * Technically, architectures with pte_special can avoid all these
1884 * restrictions (same for remap_pfn_range). However we would like
1885 * consistency in testing and feature parity among all, so we should
1886 * try to keep these invariants in place for everybody.
1888 BUG_ON(!(vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)));
1889 BUG_ON((vma
->vm_flags
& (VM_PFNMAP
|VM_MIXEDMAP
)) ==
1890 (VM_PFNMAP
|VM_MIXEDMAP
));
1891 BUG_ON((vma
->vm_flags
& VM_PFNMAP
) && is_cow_mapping(vma
->vm_flags
));
1892 BUG_ON((vma
->vm_flags
& VM_MIXEDMAP
) && pfn_valid(pfn
));
1894 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1897 if (!pfn_modify_allowed(pfn
, pgprot
))
1900 track_pfn_insert(vma
, &pgprot
, __pfn_to_pfn_t(pfn
, PFN_DEV
));
1902 ret
= insert_pfn(vma
, addr
, __pfn_to_pfn_t(pfn
, PFN_DEV
), pgprot
,
1907 EXPORT_SYMBOL(vm_insert_pfn_prot
);
1909 static int __vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1910 pfn_t pfn
, bool mkwrite
)
1912 pgprot_t pgprot
= vma
->vm_page_prot
;
1914 BUG_ON(!(vma
->vm_flags
& VM_MIXEDMAP
));
1916 if (addr
< vma
->vm_start
|| addr
>= vma
->vm_end
)
1919 track_pfn_insert(vma
, &pgprot
, pfn
);
1921 if (!pfn_modify_allowed(pfn_t_to_pfn(pfn
), pgprot
))
1925 * If we don't have pte special, then we have to use the pfn_valid()
1926 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1927 * refcount the page if pfn_valid is true (hence insert_page rather
1928 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1929 * without pte special, it would there be refcounted as a normal page.
1931 if (!HAVE_PTE_SPECIAL
&& !pfn_t_devmap(pfn
) && pfn_t_valid(pfn
)) {
1935 * At this point we are committed to insert_page()
1936 * regardless of whether the caller specified flags that
1937 * result in pfn_t_has_page() == false.
1939 page
= pfn_to_page(pfn_t_to_pfn(pfn
));
1940 return insert_page(vma
, addr
, page
, pgprot
);
1942 return insert_pfn(vma
, addr
, pfn
, pgprot
, mkwrite
);
1945 int vm_insert_mixed(struct vm_area_struct
*vma
, unsigned long addr
,
1948 return __vm_insert_mixed(vma
, addr
, pfn
, false);
1951 EXPORT_SYMBOL(vm_insert_mixed
);
1953 int vm_insert_mixed_mkwrite(struct vm_area_struct
*vma
, unsigned long addr
,
1956 return __vm_insert_mixed(vma
, addr
, pfn
, true);
1958 EXPORT_SYMBOL(vm_insert_mixed_mkwrite
);
1961 * maps a range of physical memory into the requested pages. the old
1962 * mappings are removed. any references to nonexistent pages results
1963 * in null mappings (currently treated as "copy-on-access")
1965 static int remap_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
1966 unsigned long addr
, unsigned long end
,
1967 unsigned long pfn
, pgprot_t prot
)
1973 pte
= pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
1976 arch_enter_lazy_mmu_mode();
1978 BUG_ON(!pte_none(*pte
));
1979 if (!pfn_modify_allowed(pfn
, prot
)) {
1983 set_pte_at(mm
, addr
, pte
, pte_mkspecial(pfn_pte(pfn
, prot
)));
1985 } while (pte
++, addr
+= PAGE_SIZE
, addr
!= end
);
1986 arch_leave_lazy_mmu_mode();
1987 pte_unmap_unlock(pte
- 1, ptl
);
1991 static inline int remap_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
1992 unsigned long addr
, unsigned long end
,
1993 unsigned long pfn
, pgprot_t prot
)
1999 pfn
-= addr
>> PAGE_SHIFT
;
2000 pmd
= pmd_alloc(mm
, pud
, addr
);
2003 VM_BUG_ON(pmd_trans_huge(*pmd
));
2005 next
= pmd_addr_end(addr
, end
);
2006 err
= remap_pte_range(mm
, pmd
, addr
, next
,
2007 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
2010 } while (pmd
++, addr
= next
, addr
!= end
);
2014 static inline int remap_pud_range(struct mm_struct
*mm
, p4d_t
*p4d
,
2015 unsigned long addr
, unsigned long end
,
2016 unsigned long pfn
, pgprot_t prot
)
2022 pfn
-= addr
>> PAGE_SHIFT
;
2023 pud
= pud_alloc(mm
, p4d
, addr
);
2027 next
= pud_addr_end(addr
, end
);
2028 err
= remap_pmd_range(mm
, pud
, addr
, next
,
2029 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
2032 } while (pud
++, addr
= next
, addr
!= end
);
2036 static inline int remap_p4d_range(struct mm_struct
*mm
, pgd_t
*pgd
,
2037 unsigned long addr
, unsigned long end
,
2038 unsigned long pfn
, pgprot_t prot
)
2044 pfn
-= addr
>> PAGE_SHIFT
;
2045 p4d
= p4d_alloc(mm
, pgd
, addr
);
2049 next
= p4d_addr_end(addr
, end
);
2050 err
= remap_pud_range(mm
, p4d
, addr
, next
,
2051 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
2054 } while (p4d
++, addr
= next
, addr
!= end
);
2059 * remap_pfn_range - remap kernel memory to userspace
2060 * @vma: user vma to map to
2061 * @addr: target user address to start at
2062 * @pfn: physical address of kernel memory
2063 * @size: size of map area
2064 * @prot: page protection flags for this mapping
2066 * Note: this is only safe if the mm semaphore is held when called.
2068 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
2069 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
2073 unsigned long end
= addr
+ PAGE_ALIGN(size
);
2074 struct mm_struct
*mm
= vma
->vm_mm
;
2075 unsigned long remap_pfn
= pfn
;
2079 * Physically remapped pages are special. Tell the
2080 * rest of the world about it:
2081 * VM_IO tells people not to look at these pages
2082 * (accesses can have side effects).
2083 * VM_PFNMAP tells the core MM that the base pages are just
2084 * raw PFN mappings, and do not have a "struct page" associated
2087 * Disable vma merging and expanding with mremap().
2089 * Omit vma from core dump, even when VM_IO turned off.
2091 * There's a horrible special case to handle copy-on-write
2092 * behaviour that some programs depend on. We mark the "original"
2093 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
2094 * See vm_normal_page() for details.
2096 if (is_cow_mapping(vma
->vm_flags
)) {
2097 if (addr
!= vma
->vm_start
|| end
!= vma
->vm_end
)
2099 vma
->vm_pgoff
= pfn
;
2102 err
= track_pfn_remap(vma
, &prot
, remap_pfn
, addr
, PAGE_ALIGN(size
));
2106 vma
->vm_flags
|= VM_IO
| VM_PFNMAP
| VM_DONTEXPAND
| VM_DONTDUMP
;
2108 BUG_ON(addr
>= end
);
2109 pfn
-= addr
>> PAGE_SHIFT
;
2110 pgd
= pgd_offset(mm
, addr
);
2111 flush_cache_range(vma
, addr
, end
);
2113 next
= pgd_addr_end(addr
, end
);
2114 err
= remap_p4d_range(mm
, pgd
, addr
, next
,
2115 pfn
+ (addr
>> PAGE_SHIFT
), prot
);
2118 } while (pgd
++, addr
= next
, addr
!= end
);
2121 untrack_pfn(vma
, remap_pfn
, PAGE_ALIGN(size
));
2125 EXPORT_SYMBOL(remap_pfn_range
);
2128 * vm_iomap_memory - remap memory to userspace
2129 * @vma: user vma to map to
2130 * @start: start of area
2131 * @len: size of area
2133 * This is a simplified io_remap_pfn_range() for common driver use. The
2134 * driver just needs to give us the physical memory range to be mapped,
2135 * we'll figure out the rest from the vma information.
2137 * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
2138 * whatever write-combining details or similar.
2140 int vm_iomap_memory(struct vm_area_struct
*vma
, phys_addr_t start
, unsigned long len
)
2142 unsigned long vm_len
, pfn
, pages
;
2144 /* Check that the physical memory area passed in looks valid */
2145 if (start
+ len
< start
)
2148 * You *really* shouldn't map things that aren't page-aligned,
2149 * but we've historically allowed it because IO memory might
2150 * just have smaller alignment.
2152 len
+= start
& ~PAGE_MASK
;
2153 pfn
= start
>> PAGE_SHIFT
;
2154 pages
= (len
+ ~PAGE_MASK
) >> PAGE_SHIFT
;
2155 if (pfn
+ pages
< pfn
)
2158 /* We start the mapping 'vm_pgoff' pages into the area */
2159 if (vma
->vm_pgoff
> pages
)
2161 pfn
+= vma
->vm_pgoff
;
2162 pages
-= vma
->vm_pgoff
;
2164 /* Can we fit all of the mapping? */
2165 vm_len
= vma
->vm_end
- vma
->vm_start
;
2166 if (vm_len
>> PAGE_SHIFT
> pages
)
2169 /* Ok, let it rip */
2170 return io_remap_pfn_range(vma
, vma
->vm_start
, pfn
, vm_len
, vma
->vm_page_prot
);
2172 EXPORT_SYMBOL(vm_iomap_memory
);
2174 static int apply_to_pte_range(struct mm_struct
*mm
, pmd_t
*pmd
,
2175 unsigned long addr
, unsigned long end
,
2176 pte_fn_t fn
, void *data
)
2181 spinlock_t
*uninitialized_var(ptl
);
2183 pte
= (mm
== &init_mm
) ?
2184 pte_alloc_kernel(pmd
, addr
) :
2185 pte_alloc_map_lock(mm
, pmd
, addr
, &ptl
);
2189 BUG_ON(pmd_huge(*pmd
));
2191 arch_enter_lazy_mmu_mode();
2193 token
= pmd_pgtable(*pmd
);
2196 err
= fn(pte
++, token
, addr
, data
);
2199 } while (addr
+= PAGE_SIZE
, addr
!= end
);
2201 arch_leave_lazy_mmu_mode();
2204 pte_unmap_unlock(pte
-1, ptl
);
2208 static int apply_to_pmd_range(struct mm_struct
*mm
, pud_t
*pud
,
2209 unsigned long addr
, unsigned long end
,
2210 pte_fn_t fn
, void *data
)
2216 BUG_ON(pud_huge(*pud
));
2218 pmd
= pmd_alloc(mm
, pud
, addr
);
2222 next
= pmd_addr_end(addr
, end
);
2223 err
= apply_to_pte_range(mm
, pmd
, addr
, next
, fn
, data
);
2226 } while (pmd
++, addr
= next
, addr
!= end
);
2230 static int apply_to_pud_range(struct mm_struct
*mm
, p4d_t
*p4d
,
2231 unsigned long addr
, unsigned long end
,
2232 pte_fn_t fn
, void *data
)
2238 pud
= pud_alloc(mm
, p4d
, addr
);
2242 next
= pud_addr_end(addr
, end
);
2243 err
= apply_to_pmd_range(mm
, pud
, addr
, next
, fn
, data
);
2246 } while (pud
++, addr
= next
, addr
!= end
);
2250 static int apply_to_p4d_range(struct mm_struct
*mm
, pgd_t
*pgd
,
2251 unsigned long addr
, unsigned long end
,
2252 pte_fn_t fn
, void *data
)
2258 p4d
= p4d_alloc(mm
, pgd
, addr
);
2262 next
= p4d_addr_end(addr
, end
);
2263 err
= apply_to_pud_range(mm
, p4d
, addr
, next
, fn
, data
);
2266 } while (p4d
++, addr
= next
, addr
!= end
);
2271 * Scan a region of virtual memory, filling in page tables as necessary
2272 * and calling a provided function on each leaf page table.
2274 int apply_to_page_range(struct mm_struct
*mm
, unsigned long addr
,
2275 unsigned long size
, pte_fn_t fn
, void *data
)
2279 unsigned long end
= addr
+ size
;
2282 if (WARN_ON(addr
>= end
))
2285 pgd
= pgd_offset(mm
, addr
);
2287 next
= pgd_addr_end(addr
, end
);
2288 err
= apply_to_p4d_range(mm
, pgd
, addr
, next
, fn
, data
);
2291 } while (pgd
++, addr
= next
, addr
!= end
);
2295 EXPORT_SYMBOL_GPL(apply_to_page_range
);
2298 * handle_pte_fault chooses page fault handler according to an entry which was
2299 * read non-atomically. Before making any commitment, on those architectures
2300 * or configurations (e.g. i386 with PAE) which might give a mix of unmatched
2301 * parts, do_swap_page must check under lock before unmapping the pte and
2302 * proceeding (but do_wp_page is only called after already making such a check;
2303 * and do_anonymous_page can safely check later on).
2305 static inline int pte_unmap_same(struct mm_struct
*mm
, pmd_t
*pmd
,
2306 pte_t
*page_table
, pte_t orig_pte
)
2309 #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2310 if (sizeof(pte_t
) > sizeof(unsigned long)) {
2311 spinlock_t
*ptl
= pte_lockptr(mm
, pmd
);
2313 same
= pte_same(*page_table
, orig_pte
);
2317 pte_unmap(page_table
);
2321 static inline void cow_user_page(struct page
*dst
, struct page
*src
, unsigned long va
, struct vm_area_struct
*vma
)
2323 debug_dma_assert_idle(src
);
2326 * If the source page was a PFN mapping, we don't have
2327 * a "struct page" for it. We do a best-effort copy by
2328 * just copying from the original user address. If that
2329 * fails, we just zero-fill it. Live with it.
2331 if (unlikely(!src
)) {
2332 void *kaddr
= kmap_atomic(dst
);
2333 void __user
*uaddr
= (void __user
*)(va
& PAGE_MASK
);
2336 * This really shouldn't fail, because the page is there
2337 * in the page tables. But it might just be unreadable,
2338 * in which case we just give up and fill the result with
2341 if (__copy_from_user_inatomic(kaddr
, uaddr
, PAGE_SIZE
))
2343 kunmap_atomic(kaddr
);
2344 flush_dcache_page(dst
);
2346 copy_user_highpage(dst
, src
, va
, vma
);
2349 static gfp_t
__get_fault_gfp_mask(struct vm_area_struct
*vma
)
2351 struct file
*vm_file
= vma
->vm_file
;
2354 return mapping_gfp_mask(vm_file
->f_mapping
) | __GFP_FS
| __GFP_IO
;
2357 * Special mappings (e.g. VDSO) do not have any file so fake
2358 * a default GFP_KERNEL for them.
2364 * Notify the address space that the page is about to become writable so that
2365 * it can prohibit this or wait for the page to get into an appropriate state.
2367 * We do this without the lock held, so that it can sleep if it needs to.
2369 static int do_page_mkwrite(struct vm_fault
*vmf
)
2372 struct page
*page
= vmf
->page
;
2373 unsigned int old_flags
= vmf
->flags
;
2375 vmf
->flags
= FAULT_FLAG_WRITE
|FAULT_FLAG_MKWRITE
;
2377 ret
= vmf
->vma
->vm_ops
->page_mkwrite(vmf
);
2378 /* Restore original flags so that caller is not surprised */
2379 vmf
->flags
= old_flags
;
2380 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))
2382 if (unlikely(!(ret
& VM_FAULT_LOCKED
))) {
2384 if (!page
->mapping
) {
2386 return 0; /* retry */
2388 ret
|= VM_FAULT_LOCKED
;
2390 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
2395 * Handle dirtying of a page in shared file mapping on a write fault.
2397 * The function expects the page to be locked and unlocks it.
2399 static void fault_dirty_shared_page(struct vm_area_struct
*vma
,
2402 struct address_space
*mapping
;
2404 bool page_mkwrite
= vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
;
2406 dirtied
= set_page_dirty(page
);
2407 VM_BUG_ON_PAGE(PageAnon(page
), page
);
2409 * Take a local copy of the address_space - page.mapping may be zeroed
2410 * by truncate after unlock_page(). The address_space itself remains
2411 * pinned by vma->vm_file's reference. We rely on unlock_page()'s
2412 * release semantics to prevent the compiler from undoing this copying.
2414 mapping
= page_rmapping(page
);
2417 if ((dirtied
|| page_mkwrite
) && mapping
) {
2419 * Some device drivers do not set page.mapping
2420 * but still dirty their pages
2422 balance_dirty_pages_ratelimited(mapping
);
2426 file_update_time(vma
->vm_file
);
2430 * Handle write page faults for pages that can be reused in the current vma
2432 * This can happen either due to the mapping being with the VM_SHARED flag,
2433 * or due to us being the last reference standing to the page. In either
2434 * case, all we need to do here is to mark the page as writable and update
2435 * any related book-keeping.
2437 static inline void wp_page_reuse(struct vm_fault
*vmf
)
2438 __releases(vmf
->ptl
)
2440 struct vm_area_struct
*vma
= vmf
->vma
;
2441 struct page
*page
= vmf
->page
;
2444 * Clear the pages cpupid information as the existing
2445 * information potentially belongs to a now completely
2446 * unrelated process.
2449 page_cpupid_xchg_last(page
, (1 << LAST_CPUPID_SHIFT
) - 1);
2451 flush_cache_page(vma
, vmf
->address
, pte_pfn(vmf
->orig_pte
));
2452 entry
= pte_mkyoung(vmf
->orig_pte
);
2453 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2454 if (ptep_set_access_flags(vma
, vmf
->address
, vmf
->pte
, entry
, 1))
2455 update_mmu_cache(vma
, vmf
->address
, vmf
->pte
);
2456 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2460 * Handle the case of a page which we actually need to copy to a new page.
2462 * Called with mmap_sem locked and the old page referenced, but
2463 * without the ptl held.
2465 * High level logic flow:
2467 * - Allocate a page, copy the content of the old page to the new one.
2468 * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc.
2469 * - Take the PTL. If the pte changed, bail out and release the allocated page
2470 * - If the pte is still the way we remember it, update the page table and all
2471 * relevant references. This includes dropping the reference the page-table
2472 * held to the old page, as well as updating the rmap.
2473 * - In any case, unlock the PTL and drop the reference we took to the old page.
2475 static int wp_page_copy(struct vm_fault
*vmf
)
2477 struct vm_area_struct
*vma
= vmf
->vma
;
2478 struct mm_struct
*mm
= vma
->vm_mm
;
2479 struct page
*old_page
= vmf
->page
;
2480 struct page
*new_page
= NULL
;
2482 int page_copied
= 0;
2483 const unsigned long mmun_start
= vmf
->address
& PAGE_MASK
;
2484 const unsigned long mmun_end
= mmun_start
+ PAGE_SIZE
;
2485 struct mem_cgroup
*memcg
;
2487 if (unlikely(anon_vma_prepare(vma
)))
2490 if (is_zero_pfn(pte_pfn(vmf
->orig_pte
))) {
2491 new_page
= alloc_zeroed_user_highpage_movable(vma
,
2496 new_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
,
2500 cow_user_page(new_page
, old_page
, vmf
->address
, vma
);
2503 if (mem_cgroup_try_charge(new_page
, mm
, GFP_KERNEL
, &memcg
, false))
2506 __SetPageUptodate(new_page
);
2508 mmu_notifier_invalidate_range_start(mm
, mmun_start
, mmun_end
);
2511 * Re-check the pte - we dropped the lock
2513 vmf
->pte
= pte_offset_map_lock(mm
, vmf
->pmd
, vmf
->address
, &vmf
->ptl
);
2514 if (likely(pte_same(*vmf
->pte
, vmf
->orig_pte
))) {
2516 if (!PageAnon(old_page
)) {
2517 dec_mm_counter_fast(mm
,
2518 mm_counter_file(old_page
));
2519 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
2522 inc_mm_counter_fast(mm
, MM_ANONPAGES
);
2524 flush_cache_page(vma
, vmf
->address
, pte_pfn(vmf
->orig_pte
));
2525 entry
= mk_pte(new_page
, vma
->vm_page_prot
);
2526 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
2528 * Clear the pte entry and flush it first, before updating the
2529 * pte with the new entry. This will avoid a race condition
2530 * seen in the presence of one thread doing SMC and another
2533 ptep_clear_flush_notify(vma
, vmf
->address
, vmf
->pte
);
2534 page_add_new_anon_rmap(new_page
, vma
, vmf
->address
, false);
2535 mem_cgroup_commit_charge(new_page
, memcg
, false, false);
2536 lru_cache_add_active_or_unevictable(new_page
, vma
);
2538 * We call the notify macro here because, when using secondary
2539 * mmu page tables (such as kvm shadow page tables), we want the
2540 * new page to be mapped directly into the secondary page table.
2542 set_pte_at_notify(mm
, vmf
->address
, vmf
->pte
, entry
);
2543 update_mmu_cache(vma
, vmf
->address
, vmf
->pte
);
2546 * Only after switching the pte to the new page may
2547 * we remove the mapcount here. Otherwise another
2548 * process may come and find the rmap count decremented
2549 * before the pte is switched to the new page, and
2550 * "reuse" the old page writing into it while our pte
2551 * here still points into it and can be read by other
2554 * The critical issue is to order this
2555 * page_remove_rmap with the ptp_clear_flush above.
2556 * Those stores are ordered by (if nothing else,)
2557 * the barrier present in the atomic_add_negative
2558 * in page_remove_rmap.
2560 * Then the TLB flush in ptep_clear_flush ensures that
2561 * no process can access the old page before the
2562 * decremented mapcount is visible. And the old page
2563 * cannot be reused until after the decremented
2564 * mapcount is visible. So transitively, TLBs to
2565 * old page will be flushed before it can be reused.
2567 page_remove_rmap(old_page
, false);
2570 /* Free the old page.. */
2571 new_page
= old_page
;
2574 mem_cgroup_cancel_charge(new_page
, memcg
, false);
2580 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2581 mmu_notifier_invalidate_range_end(mm
, mmun_start
, mmun_end
);
2584 * Don't let another task, with possibly unlocked vma,
2585 * keep the mlocked page.
2587 if (page_copied
&& (vma
->vm_flags
& VM_LOCKED
)) {
2588 lock_page(old_page
); /* LRU manipulation */
2589 if (PageMlocked(old_page
))
2590 munlock_vma_page(old_page
);
2591 unlock_page(old_page
);
2595 return page_copied
? VM_FAULT_WRITE
: 0;
2601 return VM_FAULT_OOM
;
2605 * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE
2606 * writeable once the page is prepared
2608 * @vmf: structure describing the fault
2610 * This function handles all that is needed to finish a write page fault in a
2611 * shared mapping due to PTE being read-only once the mapped page is prepared.
2612 * It handles locking of PTE and modifying it. The function returns
2613 * VM_FAULT_WRITE on success, 0 when PTE got changed before we acquired PTE
2616 * The function expects the page to be locked or other protection against
2617 * concurrent faults / writeback (such as DAX radix tree locks).
2619 int finish_mkwrite_fault(struct vm_fault
*vmf
)
2621 WARN_ON_ONCE(!(vmf
->vma
->vm_flags
& VM_SHARED
));
2622 vmf
->pte
= pte_offset_map_lock(vmf
->vma
->vm_mm
, vmf
->pmd
, vmf
->address
,
2625 * We might have raced with another page fault while we released the
2626 * pte_offset_map_lock.
2628 if (!pte_same(*vmf
->pte
, vmf
->orig_pte
)) {
2629 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2630 return VM_FAULT_NOPAGE
;
2637 * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED
2640 static int wp_pfn_shared(struct vm_fault
*vmf
)
2642 struct vm_area_struct
*vma
= vmf
->vma
;
2644 if (vma
->vm_ops
&& vma
->vm_ops
->pfn_mkwrite
) {
2647 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2648 vmf
->flags
|= FAULT_FLAG_MKWRITE
;
2649 ret
= vma
->vm_ops
->pfn_mkwrite(vmf
);
2650 if (ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))
2652 return finish_mkwrite_fault(vmf
);
2655 return VM_FAULT_WRITE
;
2658 static int wp_page_shared(struct vm_fault
*vmf
)
2659 __releases(vmf
->ptl
)
2661 struct vm_area_struct
*vma
= vmf
->vma
;
2663 get_page(vmf
->page
);
2665 if (vma
->vm_ops
&& vma
->vm_ops
->page_mkwrite
) {
2668 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2669 tmp
= do_page_mkwrite(vmf
);
2670 if (unlikely(!tmp
|| (tmp
&
2671 (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))) {
2672 put_page(vmf
->page
);
2675 tmp
= finish_mkwrite_fault(vmf
);
2676 if (unlikely(tmp
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
))) {
2677 unlock_page(vmf
->page
);
2678 put_page(vmf
->page
);
2683 lock_page(vmf
->page
);
2685 fault_dirty_shared_page(vma
, vmf
->page
);
2686 put_page(vmf
->page
);
2688 return VM_FAULT_WRITE
;
2692 * This routine handles present pages, when users try to write
2693 * to a shared page. It is done by copying the page to a new address
2694 * and decrementing the shared-page counter for the old page.
2696 * Note that this routine assumes that the protection checks have been
2697 * done by the caller (the low-level page fault routine in most cases).
2698 * Thus we can safely just mark it writable once we've done any necessary
2701 * We also mark the page dirty at this point even though the page will
2702 * change only once the write actually happens. This avoids a few races,
2703 * and potentially makes it more efficient.
2705 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2706 * but allow concurrent faults), with pte both mapped and locked.
2707 * We return with mmap_sem still held, but pte unmapped and unlocked.
2709 static int do_wp_page(struct vm_fault
*vmf
)
2710 __releases(vmf
->ptl
)
2712 struct vm_area_struct
*vma
= vmf
->vma
;
2714 vmf
->page
= vm_normal_page(vma
, vmf
->address
, vmf
->orig_pte
);
2717 * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
2720 * We should not cow pages in a shared writeable mapping.
2721 * Just mark the pages writable and/or call ops->pfn_mkwrite.
2723 if ((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
2724 (VM_WRITE
|VM_SHARED
))
2725 return wp_pfn_shared(vmf
);
2727 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2728 return wp_page_copy(vmf
);
2732 * Take out anonymous pages first, anonymous shared vmas are
2733 * not dirty accountable.
2735 if (PageAnon(vmf
->page
) && !PageKsm(vmf
->page
)) {
2736 int total_map_swapcount
;
2737 if (!trylock_page(vmf
->page
)) {
2738 get_page(vmf
->page
);
2739 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2740 lock_page(vmf
->page
);
2741 vmf
->pte
= pte_offset_map_lock(vma
->vm_mm
, vmf
->pmd
,
2742 vmf
->address
, &vmf
->ptl
);
2743 if (!pte_same(*vmf
->pte
, vmf
->orig_pte
)) {
2744 unlock_page(vmf
->page
);
2745 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2746 put_page(vmf
->page
);
2749 put_page(vmf
->page
);
2751 if (reuse_swap_page(vmf
->page
, &total_map_swapcount
)) {
2752 if (total_map_swapcount
== 1) {
2754 * The page is all ours. Move it to
2755 * our anon_vma so the rmap code will
2756 * not search our parent or siblings.
2757 * Protected against the rmap code by
2760 page_move_anon_rmap(vmf
->page
, vma
);
2762 unlock_page(vmf
->page
);
2764 return VM_FAULT_WRITE
;
2766 unlock_page(vmf
->page
);
2767 } else if (unlikely((vma
->vm_flags
& (VM_WRITE
|VM_SHARED
)) ==
2768 (VM_WRITE
|VM_SHARED
))) {
2769 return wp_page_shared(vmf
);
2773 * Ok, we need to copy. Oh, well..
2775 get_page(vmf
->page
);
2777 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
2778 return wp_page_copy(vmf
);
2781 static void unmap_mapping_range_vma(struct vm_area_struct
*vma
,
2782 unsigned long start_addr
, unsigned long end_addr
,
2783 struct zap_details
*details
)
2785 zap_page_range_single(vma
, start_addr
, end_addr
- start_addr
, details
);
2788 static inline void unmap_mapping_range_tree(struct rb_root_cached
*root
,
2789 struct zap_details
*details
)
2791 struct vm_area_struct
*vma
;
2792 pgoff_t vba
, vea
, zba
, zea
;
2794 vma_interval_tree_foreach(vma
, root
,
2795 details
->first_index
, details
->last_index
) {
2797 vba
= vma
->vm_pgoff
;
2798 vea
= vba
+ vma_pages(vma
) - 1;
2799 zba
= details
->first_index
;
2802 zea
= details
->last_index
;
2806 unmap_mapping_range_vma(vma
,
2807 ((zba
- vba
) << PAGE_SHIFT
) + vma
->vm_start
,
2808 ((zea
- vba
+ 1) << PAGE_SHIFT
) + vma
->vm_start
,
2814 * unmap_mapping_range - unmap the portion of all mmaps in the specified
2815 * address_space corresponding to the specified page range in the underlying
2818 * @mapping: the address space containing mmaps to be unmapped.
2819 * @holebegin: byte in first page to unmap, relative to the start of
2820 * the underlying file. This will be rounded down to a PAGE_SIZE
2821 * boundary. Note that this is different from truncate_pagecache(), which
2822 * must keep the partial page. In contrast, we must get rid of
2824 * @holelen: size of prospective hole in bytes. This will be rounded
2825 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2827 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2828 * but 0 when invalidating pagecache, don't throw away private data.
2830 void unmap_mapping_range(struct address_space
*mapping
,
2831 loff_t
const holebegin
, loff_t
const holelen
, int even_cows
)
2833 struct zap_details details
= { };
2834 pgoff_t hba
= holebegin
>> PAGE_SHIFT
;
2835 pgoff_t hlen
= (holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2837 /* Check for overflow. */
2838 if (sizeof(holelen
) > sizeof(hlen
)) {
2840 (holebegin
+ holelen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
2841 if (holeend
& ~(long long)ULONG_MAX
)
2842 hlen
= ULONG_MAX
- hba
+ 1;
2845 details
.check_mapping
= even_cows
? NULL
: mapping
;
2846 details
.first_index
= hba
;
2847 details
.last_index
= hba
+ hlen
- 1;
2848 if (details
.last_index
< details
.first_index
)
2849 details
.last_index
= ULONG_MAX
;
2851 i_mmap_lock_write(mapping
);
2852 if (unlikely(!RB_EMPTY_ROOT(&mapping
->i_mmap
.rb_root
)))
2853 unmap_mapping_range_tree(&mapping
->i_mmap
, &details
);
2854 i_mmap_unlock_write(mapping
);
2856 EXPORT_SYMBOL(unmap_mapping_range
);
2859 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2860 * but allow concurrent faults), and pte mapped but not yet locked.
2861 * We return with pte unmapped and unlocked.
2863 * We return with the mmap_sem locked or unlocked in the same cases
2864 * as does filemap_fault().
2866 int do_swap_page(struct vm_fault
*vmf
)
2868 struct vm_area_struct
*vma
= vmf
->vma
;
2869 struct page
*page
= NULL
, *swapcache
;
2870 struct mem_cgroup
*memcg
;
2871 struct vma_swap_readahead swap_ra
;
2877 bool vma_readahead
= swap_use_vma_readahead();
2880 page
= swap_readahead_detect(vmf
, &swap_ra
);
2881 if (!pte_unmap_same(vma
->vm_mm
, vmf
->pmd
, vmf
->pte
, vmf
->orig_pte
)) {
2887 entry
= pte_to_swp_entry(vmf
->orig_pte
);
2888 if (unlikely(non_swap_entry(entry
))) {
2889 if (is_migration_entry(entry
)) {
2890 migration_entry_wait(vma
->vm_mm
, vmf
->pmd
,
2892 } else if (is_device_private_entry(entry
)) {
2894 * For un-addressable device memory we call the pgmap
2895 * fault handler callback. The callback must migrate
2896 * the page back to some CPU accessible page.
2898 ret
= device_private_entry_fault(vma
, vmf
->address
, entry
,
2899 vmf
->flags
, vmf
->pmd
);
2900 } else if (is_hwpoison_entry(entry
)) {
2901 ret
= VM_FAULT_HWPOISON
;
2903 print_bad_pte(vma
, vmf
->address
, vmf
->orig_pte
, NULL
);
2904 ret
= VM_FAULT_SIGBUS
;
2908 delayacct_set_flag(DELAYACCT_PF_SWAPIN
);
2910 page
= lookup_swap_cache(entry
, vma_readahead
? vma
: NULL
,
2914 page
= do_swap_page_readahead(entry
,
2915 GFP_HIGHUSER_MOVABLE
, vmf
, &swap_ra
);
2917 page
= swapin_readahead(entry
,
2918 GFP_HIGHUSER_MOVABLE
, vma
, vmf
->address
);
2921 * Back out if somebody else faulted in this pte
2922 * while we released the pte lock.
2924 vmf
->pte
= pte_offset_map_lock(vma
->vm_mm
, vmf
->pmd
,
2925 vmf
->address
, &vmf
->ptl
);
2926 if (likely(pte_same(*vmf
->pte
, vmf
->orig_pte
)))
2928 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2932 /* Had to read the page from swap area: Major fault */
2933 ret
= VM_FAULT_MAJOR
;
2934 count_vm_event(PGMAJFAULT
);
2935 count_memcg_event_mm(vma
->vm_mm
, PGMAJFAULT
);
2936 } else if (PageHWPoison(page
)) {
2938 * hwpoisoned dirty swapcache pages are kept for killing
2939 * owner processes (which may be unknown at hwpoison time)
2941 ret
= VM_FAULT_HWPOISON
;
2942 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2948 locked
= lock_page_or_retry(page
, vma
->vm_mm
, vmf
->flags
);
2950 delayacct_clear_flag(DELAYACCT_PF_SWAPIN
);
2952 ret
|= VM_FAULT_RETRY
;
2957 * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
2958 * release the swapcache from under us. The page pin, and pte_same
2959 * test below, are not enough to exclude that. Even if it is still
2960 * swapcache, we need to check that the page's swap has not changed.
2962 if (unlikely(!PageSwapCache(page
) || page_private(page
) != entry
.val
))
2965 page
= ksm_might_need_to_copy(page
, vma
, vmf
->address
);
2966 if (unlikely(!page
)) {
2972 if (mem_cgroup_try_charge(page
, vma
->vm_mm
, GFP_KERNEL
,
2979 * Back out if somebody else already faulted in this pte.
2981 vmf
->pte
= pte_offset_map_lock(vma
->vm_mm
, vmf
->pmd
, vmf
->address
,
2983 if (unlikely(!pte_same(*vmf
->pte
, vmf
->orig_pte
)))
2986 if (unlikely(!PageUptodate(page
))) {
2987 ret
= VM_FAULT_SIGBUS
;
2992 * The page isn't present yet, go ahead with the fault.
2994 * Be careful about the sequence of operations here.
2995 * To get its accounting right, reuse_swap_page() must be called
2996 * while the page is counted on swap but not yet in mapcount i.e.
2997 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2998 * must be called after the swap_free(), or it will never succeed.
3001 inc_mm_counter_fast(vma
->vm_mm
, MM_ANONPAGES
);
3002 dec_mm_counter_fast(vma
->vm_mm
, MM_SWAPENTS
);
3003 pte
= mk_pte(page
, vma
->vm_page_prot
);
3004 if ((vmf
->flags
& FAULT_FLAG_WRITE
) && reuse_swap_page(page
, NULL
)) {
3005 pte
= maybe_mkwrite(pte_mkdirty(pte
), vma
);
3006 vmf
->flags
&= ~FAULT_FLAG_WRITE
;
3007 ret
|= VM_FAULT_WRITE
;
3008 exclusive
= RMAP_EXCLUSIVE
;
3010 flush_icache_page(vma
, page
);
3011 if (pte_swp_soft_dirty(vmf
->orig_pte
))
3012 pte
= pte_mksoft_dirty(pte
);
3013 set_pte_at(vma
->vm_mm
, vmf
->address
, vmf
->pte
, pte
);
3014 vmf
->orig_pte
= pte
;
3015 if (page
== swapcache
) {
3016 do_page_add_anon_rmap(page
, vma
, vmf
->address
, exclusive
);
3017 mem_cgroup_commit_charge(page
, memcg
, true, false);
3018 activate_page(page
);
3019 } else { /* ksm created a completely new copy */
3020 page_add_new_anon_rmap(page
, vma
, vmf
->address
, false);
3021 mem_cgroup_commit_charge(page
, memcg
, false, false);
3022 lru_cache_add_active_or_unevictable(page
, vma
);
3026 if (mem_cgroup_swap_full(page
) ||
3027 (vma
->vm_flags
& VM_LOCKED
) || PageMlocked(page
))
3028 try_to_free_swap(page
);
3030 if (page
!= swapcache
) {
3032 * Hold the lock to avoid the swap entry to be reused
3033 * until we take the PT lock for the pte_same() check
3034 * (to avoid false positives from pte_same). For
3035 * further safety release the lock after the swap_free
3036 * so that the swap count won't change under a
3037 * parallel locked swapcache.
3039 unlock_page(swapcache
);
3040 put_page(swapcache
);
3043 if (vmf
->flags
& FAULT_FLAG_WRITE
) {
3044 ret
|= do_wp_page(vmf
);
3045 if (ret
& VM_FAULT_ERROR
)
3046 ret
&= VM_FAULT_ERROR
;
3050 /* No need to invalidate - it was non-present before */
3051 update_mmu_cache(vma
, vmf
->address
, vmf
->pte
);
3053 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3057 mem_cgroup_cancel_charge(page
, memcg
, false);
3058 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3063 if (page
!= swapcache
) {
3064 unlock_page(swapcache
);
3065 put_page(swapcache
);
3071 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3072 * but allow concurrent faults), and pte mapped but not yet locked.
3073 * We return with mmap_sem still held, but pte unmapped and unlocked.
3075 static int do_anonymous_page(struct vm_fault
*vmf
)
3077 struct vm_area_struct
*vma
= vmf
->vma
;
3078 struct mem_cgroup
*memcg
;
3083 /* File mapping without ->vm_ops ? */
3084 if (vma
->vm_flags
& VM_SHARED
)
3085 return VM_FAULT_SIGBUS
;
3088 * Use pte_alloc() instead of pte_alloc_map(). We can't run
3089 * pte_offset_map() on pmds where a huge pmd might be created
3090 * from a different thread.
3092 * pte_alloc_map() is safe to use under down_write(mmap_sem) or when
3093 * parallel threads are excluded by other means.
3095 * Here we only have down_read(mmap_sem).
3097 if (pte_alloc(vma
->vm_mm
, vmf
->pmd
, vmf
->address
))
3098 return VM_FAULT_OOM
;
3100 /* See the comment in pte_alloc_one_map() */
3101 if (unlikely(pmd_trans_unstable(vmf
->pmd
)))
3104 /* Use the zero-page for reads */
3105 if (!(vmf
->flags
& FAULT_FLAG_WRITE
) &&
3106 !mm_forbids_zeropage(vma
->vm_mm
)) {
3107 entry
= pte_mkspecial(pfn_pte(my_zero_pfn(vmf
->address
),
3108 vma
->vm_page_prot
));
3109 vmf
->pte
= pte_offset_map_lock(vma
->vm_mm
, vmf
->pmd
,
3110 vmf
->address
, &vmf
->ptl
);
3111 if (!pte_none(*vmf
->pte
))
3113 ret
= check_stable_address_space(vma
->vm_mm
);
3116 /* Deliver the page fault to userland, check inside PT lock */
3117 if (userfaultfd_missing(vma
)) {
3118 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3119 return handle_userfault(vmf
, VM_UFFD_MISSING
);
3124 /* Allocate our own private page. */
3125 if (unlikely(anon_vma_prepare(vma
)))
3127 page
= alloc_zeroed_user_highpage_movable(vma
, vmf
->address
);
3131 if (mem_cgroup_try_charge(page
, vma
->vm_mm
, GFP_KERNEL
, &memcg
, false))
3135 * The memory barrier inside __SetPageUptodate makes sure that
3136 * preceeding stores to the page contents become visible before
3137 * the set_pte_at() write.
3139 __SetPageUptodate(page
);
3141 entry
= mk_pte(page
, vma
->vm_page_prot
);
3142 if (vma
->vm_flags
& VM_WRITE
)
3143 entry
= pte_mkwrite(pte_mkdirty(entry
));
3145 vmf
->pte
= pte_offset_map_lock(vma
->vm_mm
, vmf
->pmd
, vmf
->address
,
3147 if (!pte_none(*vmf
->pte
))
3150 ret
= check_stable_address_space(vma
->vm_mm
);
3154 /* Deliver the page fault to userland, check inside PT lock */
3155 if (userfaultfd_missing(vma
)) {
3156 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3157 mem_cgroup_cancel_charge(page
, memcg
, false);
3159 return handle_userfault(vmf
, VM_UFFD_MISSING
);
3162 inc_mm_counter_fast(vma
->vm_mm
, MM_ANONPAGES
);
3163 page_add_new_anon_rmap(page
, vma
, vmf
->address
, false);
3164 mem_cgroup_commit_charge(page
, memcg
, false, false);
3165 lru_cache_add_active_or_unevictable(page
, vma
);
3167 set_pte_at(vma
->vm_mm
, vmf
->address
, vmf
->pte
, entry
);
3169 /* No need to invalidate - it was non-present before */
3170 update_mmu_cache(vma
, vmf
->address
, vmf
->pte
);
3172 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3175 mem_cgroup_cancel_charge(page
, memcg
, false);
3181 return VM_FAULT_OOM
;
3185 * The mmap_sem must have been held on entry, and may have been
3186 * released depending on flags and vma->vm_ops->fault() return value.
3187 * See filemap_fault() and __lock_page_retry().
3189 static int __do_fault(struct vm_fault
*vmf
)
3191 struct vm_area_struct
*vma
= vmf
->vma
;
3194 ret
= vma
->vm_ops
->fault(vmf
);
3195 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
| VM_FAULT_RETRY
|
3196 VM_FAULT_DONE_COW
)))
3199 if (unlikely(PageHWPoison(vmf
->page
))) {
3200 if (ret
& VM_FAULT_LOCKED
)
3201 unlock_page(vmf
->page
);
3202 put_page(vmf
->page
);
3204 return VM_FAULT_HWPOISON
;
3207 if (unlikely(!(ret
& VM_FAULT_LOCKED
)))
3208 lock_page(vmf
->page
);
3210 VM_BUG_ON_PAGE(!PageLocked(vmf
->page
), vmf
->page
);
3216 * The ordering of these checks is important for pmds with _PAGE_DEVMAP set.
3217 * If we check pmd_trans_unstable() first we will trip the bad_pmd() check
3218 * inside of pmd_none_or_trans_huge_or_clear_bad(). This will end up correctly
3219 * returning 1 but not before it spams dmesg with the pmd_clear_bad() output.
3221 static int pmd_devmap_trans_unstable(pmd_t
*pmd
)
3223 return pmd_devmap(*pmd
) || pmd_trans_unstable(pmd
);
3226 static int pte_alloc_one_map(struct vm_fault
*vmf
)
3228 struct vm_area_struct
*vma
= vmf
->vma
;
3230 if (!pmd_none(*vmf
->pmd
))
3232 if (vmf
->prealloc_pte
) {
3233 vmf
->ptl
= pmd_lock(vma
->vm_mm
, vmf
->pmd
);
3234 if (unlikely(!pmd_none(*vmf
->pmd
))) {
3235 spin_unlock(vmf
->ptl
);
3239 atomic_long_inc(&vma
->vm_mm
->nr_ptes
);
3240 pmd_populate(vma
->vm_mm
, vmf
->pmd
, vmf
->prealloc_pte
);
3241 spin_unlock(vmf
->ptl
);
3242 vmf
->prealloc_pte
= NULL
;
3243 } else if (unlikely(pte_alloc(vma
->vm_mm
, vmf
->pmd
, vmf
->address
))) {
3244 return VM_FAULT_OOM
;
3248 * If a huge pmd materialized under us just retry later. Use
3249 * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead of
3250 * pmd_trans_huge() to ensure the pmd didn't become pmd_trans_huge
3251 * under us and then back to pmd_none, as a result of MADV_DONTNEED
3252 * running immediately after a huge pmd fault in a different thread of
3253 * this mm, in turn leading to a misleading pmd_trans_huge() retval.
3254 * All we have to ensure is that it is a regular pmd that we can walk
3255 * with pte_offset_map() and we can do that through an atomic read in
3256 * C, which is what pmd_trans_unstable() provides.
3258 if (pmd_devmap_trans_unstable(vmf
->pmd
))
3259 return VM_FAULT_NOPAGE
;
3262 * At this point we know that our vmf->pmd points to a page of ptes
3263 * and it cannot become pmd_none(), pmd_devmap() or pmd_trans_huge()
3264 * for the duration of the fault. If a racing MADV_DONTNEED runs and
3265 * we zap the ptes pointed to by our vmf->pmd, the vmf->ptl will still
3266 * be valid and we will re-check to make sure the vmf->pte isn't
3267 * pte_none() under vmf->ptl protection when we return to
3270 vmf
->pte
= pte_offset_map_lock(vma
->vm_mm
, vmf
->pmd
, vmf
->address
,
3275 #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3277 #define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1)
3278 static inline bool transhuge_vma_suitable(struct vm_area_struct
*vma
,
3279 unsigned long haddr
)
3281 if (((vma
->vm_start
>> PAGE_SHIFT
) & HPAGE_CACHE_INDEX_MASK
) !=
3282 (vma
->vm_pgoff
& HPAGE_CACHE_INDEX_MASK
))
3284 if (haddr
< vma
->vm_start
|| haddr
+ HPAGE_PMD_SIZE
> vma
->vm_end
)
3289 static void deposit_prealloc_pte(struct vm_fault
*vmf
)
3291 struct vm_area_struct
*vma
= vmf
->vma
;
3293 pgtable_trans_huge_deposit(vma
->vm_mm
, vmf
->pmd
, vmf
->prealloc_pte
);
3295 * We are going to consume the prealloc table,
3296 * count that as nr_ptes.
3298 atomic_long_inc(&vma
->vm_mm
->nr_ptes
);
3299 vmf
->prealloc_pte
= NULL
;
3302 static int do_set_pmd(struct vm_fault
*vmf
, struct page
*page
)
3304 struct vm_area_struct
*vma
= vmf
->vma
;
3305 bool write
= vmf
->flags
& FAULT_FLAG_WRITE
;
3306 unsigned long haddr
= vmf
->address
& HPAGE_PMD_MASK
;
3310 if (!transhuge_vma_suitable(vma
, haddr
))
3311 return VM_FAULT_FALLBACK
;
3313 ret
= VM_FAULT_FALLBACK
;
3314 page
= compound_head(page
);
3317 * Archs like ppc64 need additonal space to store information
3318 * related to pte entry. Use the preallocated table for that.
3320 if (arch_needs_pgtable_deposit() && !vmf
->prealloc_pte
) {
3321 vmf
->prealloc_pte
= pte_alloc_one(vma
->vm_mm
, vmf
->address
);
3322 if (!vmf
->prealloc_pte
)
3323 return VM_FAULT_OOM
;
3324 smp_wmb(); /* See comment in __pte_alloc() */
3327 vmf
->ptl
= pmd_lock(vma
->vm_mm
, vmf
->pmd
);
3328 if (unlikely(!pmd_none(*vmf
->pmd
)))
3331 for (i
= 0; i
< HPAGE_PMD_NR
; i
++)
3332 flush_icache_page(vma
, page
+ i
);
3334 entry
= mk_huge_pmd(page
, vma
->vm_page_prot
);
3336 entry
= maybe_pmd_mkwrite(pmd_mkdirty(entry
), vma
);
3338 add_mm_counter(vma
->vm_mm
, MM_FILEPAGES
, HPAGE_PMD_NR
);
3339 page_add_file_rmap(page
, true);
3341 * deposit and withdraw with pmd lock held
3343 if (arch_needs_pgtable_deposit())
3344 deposit_prealloc_pte(vmf
);
3346 set_pmd_at(vma
->vm_mm
, haddr
, vmf
->pmd
, entry
);
3348 update_mmu_cache_pmd(vma
, haddr
, vmf
->pmd
);
3350 /* fault is handled */
3352 count_vm_event(THP_FILE_MAPPED
);
3354 spin_unlock(vmf
->ptl
);
3358 static int do_set_pmd(struct vm_fault
*vmf
, struct page
*page
)
3366 * alloc_set_pte - setup new PTE entry for given page and add reverse page
3367 * mapping. If needed, the fucntion allocates page table or use pre-allocated.
3369 * @vmf: fault environment
3370 * @memcg: memcg to charge page (only for private mappings)
3371 * @page: page to map
3373 * Caller must take care of unlocking vmf->ptl, if vmf->pte is non-NULL on
3376 * Target users are page handler itself and implementations of
3377 * vm_ops->map_pages.
3379 int alloc_set_pte(struct vm_fault
*vmf
, struct mem_cgroup
*memcg
,
3382 struct vm_area_struct
*vma
= vmf
->vma
;
3383 bool write
= vmf
->flags
& FAULT_FLAG_WRITE
;
3387 if (pmd_none(*vmf
->pmd
) && PageTransCompound(page
) &&
3388 IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE
)) {
3390 VM_BUG_ON_PAGE(memcg
, page
);
3392 ret
= do_set_pmd(vmf
, page
);
3393 if (ret
!= VM_FAULT_FALLBACK
)
3398 ret
= pte_alloc_one_map(vmf
);
3403 /* Re-check under ptl */
3404 if (unlikely(!pte_none(*vmf
->pte
)))
3405 return VM_FAULT_NOPAGE
;
3407 flush_icache_page(vma
, page
);
3408 entry
= mk_pte(page
, vma
->vm_page_prot
);
3410 entry
= maybe_mkwrite(pte_mkdirty(entry
), vma
);
3411 /* copy-on-write page */
3412 if (write
&& !(vma
->vm_flags
& VM_SHARED
)) {
3413 inc_mm_counter_fast(vma
->vm_mm
, MM_ANONPAGES
);
3414 page_add_new_anon_rmap(page
, vma
, vmf
->address
, false);
3415 mem_cgroup_commit_charge(page
, memcg
, false, false);
3416 lru_cache_add_active_or_unevictable(page
, vma
);
3418 inc_mm_counter_fast(vma
->vm_mm
, mm_counter_file(page
));
3419 page_add_file_rmap(page
, false);
3421 set_pte_at(vma
->vm_mm
, vmf
->address
, vmf
->pte
, entry
);
3423 /* no need to invalidate: a not-present page won't be cached */
3424 update_mmu_cache(vma
, vmf
->address
, vmf
->pte
);
3431 * finish_fault - finish page fault once we have prepared the page to fault
3433 * @vmf: structure describing the fault
3435 * This function handles all that is needed to finish a page fault once the
3436 * page to fault in is prepared. It handles locking of PTEs, inserts PTE for
3437 * given page, adds reverse page mapping, handles memcg charges and LRU
3438 * addition. The function returns 0 on success, VM_FAULT_ code in case of
3441 * The function expects the page to be locked and on success it consumes a
3442 * reference of a page being mapped (for the PTE which maps it).
3444 int finish_fault(struct vm_fault
*vmf
)
3449 /* Did we COW the page? */
3450 if ((vmf
->flags
& FAULT_FLAG_WRITE
) &&
3451 !(vmf
->vma
->vm_flags
& VM_SHARED
))
3452 page
= vmf
->cow_page
;
3457 * check even for read faults because we might have lost our CoWed
3460 if (!(vmf
->vma
->vm_flags
& VM_SHARED
))
3461 ret
= check_stable_address_space(vmf
->vma
->vm_mm
);
3463 ret
= alloc_set_pte(vmf
, vmf
->memcg
, page
);
3465 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3469 static unsigned long fault_around_bytes __read_mostly
=
3470 rounddown_pow_of_two(65536);
3472 #ifdef CONFIG_DEBUG_FS
3473 static int fault_around_bytes_get(void *data
, u64
*val
)
3475 *val
= fault_around_bytes
;
3480 * fault_around_pages() and fault_around_mask() expects fault_around_bytes
3481 * rounded down to nearest page order. It's what do_fault_around() expects to
3484 static int fault_around_bytes_set(void *data
, u64 val
)
3486 if (val
/ PAGE_SIZE
> PTRS_PER_PTE
)
3488 if (val
> PAGE_SIZE
)
3489 fault_around_bytes
= rounddown_pow_of_two(val
);
3491 fault_around_bytes
= PAGE_SIZE
; /* rounddown_pow_of_two(0) is undefined */
3494 DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops
,
3495 fault_around_bytes_get
, fault_around_bytes_set
, "%llu\n");
3497 static int __init
fault_around_debugfs(void)
3501 ret
= debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL
, NULL
,
3502 &fault_around_bytes_fops
);
3504 pr_warn("Failed to create fault_around_bytes in debugfs");
3507 late_initcall(fault_around_debugfs
);
3511 * do_fault_around() tries to map few pages around the fault address. The hope
3512 * is that the pages will be needed soon and this will lower the number of
3515 * It uses vm_ops->map_pages() to map the pages, which skips the page if it's
3516 * not ready to be mapped: not up-to-date, locked, etc.
3518 * This function is called with the page table lock taken. In the split ptlock
3519 * case the page table lock only protects only those entries which belong to
3520 * the page table corresponding to the fault address.
3522 * This function doesn't cross the VMA boundaries, in order to call map_pages()
3525 * fault_around_pages() defines how many pages we'll try to map.
3526 * do_fault_around() expects it to return a power of two less than or equal to
3529 * The virtual address of the area that we map is naturally aligned to the
3530 * fault_around_pages() value (and therefore to page order). This way it's
3531 * easier to guarantee that we don't cross page table boundaries.
3533 static int do_fault_around(struct vm_fault
*vmf
)
3535 unsigned long address
= vmf
->address
, nr_pages
, mask
;
3536 pgoff_t start_pgoff
= vmf
->pgoff
;
3540 nr_pages
= READ_ONCE(fault_around_bytes
) >> PAGE_SHIFT
;
3541 mask
= ~(nr_pages
* PAGE_SIZE
- 1) & PAGE_MASK
;
3543 vmf
->address
= max(address
& mask
, vmf
->vma
->vm_start
);
3544 off
= ((address
- vmf
->address
) >> PAGE_SHIFT
) & (PTRS_PER_PTE
- 1);
3548 * end_pgoff is either end of page table or end of vma
3549 * or fault_around_pages() from start_pgoff, depending what is nearest.
3551 end_pgoff
= start_pgoff
-
3552 ((vmf
->address
>> PAGE_SHIFT
) & (PTRS_PER_PTE
- 1)) +
3554 end_pgoff
= min3(end_pgoff
, vma_pages(vmf
->vma
) + vmf
->vma
->vm_pgoff
- 1,
3555 start_pgoff
+ nr_pages
- 1);
3557 if (pmd_none(*vmf
->pmd
)) {
3558 vmf
->prealloc_pte
= pte_alloc_one(vmf
->vma
->vm_mm
,
3560 if (!vmf
->prealloc_pte
)
3562 smp_wmb(); /* See comment in __pte_alloc() */
3565 vmf
->vma
->vm_ops
->map_pages(vmf
, start_pgoff
, end_pgoff
);
3567 /* Huge page is mapped? Page fault is solved */
3568 if (pmd_trans_huge(*vmf
->pmd
)) {
3569 ret
= VM_FAULT_NOPAGE
;
3573 /* ->map_pages() haven't done anything useful. Cold page cache? */
3577 /* check if the page fault is solved */
3578 vmf
->pte
-= (vmf
->address
>> PAGE_SHIFT
) - (address
>> PAGE_SHIFT
);
3579 if (!pte_none(*vmf
->pte
))
3580 ret
= VM_FAULT_NOPAGE
;
3581 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3583 vmf
->address
= address
;
3588 static int do_read_fault(struct vm_fault
*vmf
)
3590 struct vm_area_struct
*vma
= vmf
->vma
;
3594 * Let's call ->map_pages() first and use ->fault() as fallback
3595 * if page by the offset is not ready to be mapped (cold cache or
3598 if (vma
->vm_ops
->map_pages
&& fault_around_bytes
>> PAGE_SHIFT
> 1) {
3599 ret
= do_fault_around(vmf
);
3604 ret
= __do_fault(vmf
);
3605 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
| VM_FAULT_RETRY
)))
3608 ret
|= finish_fault(vmf
);
3609 unlock_page(vmf
->page
);
3610 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
| VM_FAULT_RETRY
)))
3611 put_page(vmf
->page
);
3615 static int do_cow_fault(struct vm_fault
*vmf
)
3617 struct vm_area_struct
*vma
= vmf
->vma
;
3620 if (unlikely(anon_vma_prepare(vma
)))
3621 return VM_FAULT_OOM
;
3623 vmf
->cow_page
= alloc_page_vma(GFP_HIGHUSER_MOVABLE
, vma
, vmf
->address
);
3625 return VM_FAULT_OOM
;
3627 if (mem_cgroup_try_charge(vmf
->cow_page
, vma
->vm_mm
, GFP_KERNEL
,
3628 &vmf
->memcg
, false)) {
3629 put_page(vmf
->cow_page
);
3630 return VM_FAULT_OOM
;
3633 ret
= __do_fault(vmf
);
3634 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
| VM_FAULT_RETRY
)))
3636 if (ret
& VM_FAULT_DONE_COW
)
3639 copy_user_highpage(vmf
->cow_page
, vmf
->page
, vmf
->address
, vma
);
3640 __SetPageUptodate(vmf
->cow_page
);
3642 ret
|= finish_fault(vmf
);
3643 unlock_page(vmf
->page
);
3644 put_page(vmf
->page
);
3645 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
| VM_FAULT_RETRY
)))
3649 mem_cgroup_cancel_charge(vmf
->cow_page
, vmf
->memcg
, false);
3650 put_page(vmf
->cow_page
);
3654 static int do_shared_fault(struct vm_fault
*vmf
)
3656 struct vm_area_struct
*vma
= vmf
->vma
;
3659 ret
= __do_fault(vmf
);
3660 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
| VM_FAULT_RETRY
)))
3664 * Check if the backing address space wants to know that the page is
3665 * about to become writable
3667 if (vma
->vm_ops
->page_mkwrite
) {
3668 unlock_page(vmf
->page
);
3669 tmp
= do_page_mkwrite(vmf
);
3670 if (unlikely(!tmp
||
3671 (tmp
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
)))) {
3672 put_page(vmf
->page
);
3677 ret
|= finish_fault(vmf
);
3678 if (unlikely(ret
& (VM_FAULT_ERROR
| VM_FAULT_NOPAGE
|
3680 unlock_page(vmf
->page
);
3681 put_page(vmf
->page
);
3685 fault_dirty_shared_page(vma
, vmf
->page
);
3690 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3691 * but allow concurrent faults).
3692 * The mmap_sem may have been released depending on flags and our
3693 * return value. See filemap_fault() and __lock_page_or_retry().
3695 static int do_fault(struct vm_fault
*vmf
)
3697 struct vm_area_struct
*vma
= vmf
->vma
;
3700 /* The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */
3701 if (!vma
->vm_ops
->fault
)
3702 ret
= VM_FAULT_SIGBUS
;
3703 else if (!(vmf
->flags
& FAULT_FLAG_WRITE
))
3704 ret
= do_read_fault(vmf
);
3705 else if (!(vma
->vm_flags
& VM_SHARED
))
3706 ret
= do_cow_fault(vmf
);
3708 ret
= do_shared_fault(vmf
);
3710 /* preallocated pagetable is unused: free it */
3711 if (vmf
->prealloc_pte
) {
3712 pte_free(vma
->vm_mm
, vmf
->prealloc_pte
);
3713 vmf
->prealloc_pte
= NULL
;
3718 static int numa_migrate_prep(struct page
*page
, struct vm_area_struct
*vma
,
3719 unsigned long addr
, int page_nid
,
3724 count_vm_numa_event(NUMA_HINT_FAULTS
);
3725 if (page_nid
== numa_node_id()) {
3726 count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL
);
3727 *flags
|= TNF_FAULT_LOCAL
;
3730 return mpol_misplaced(page
, vma
, addr
);
3733 static int do_numa_page(struct vm_fault
*vmf
)
3735 struct vm_area_struct
*vma
= vmf
->vma
;
3736 struct page
*page
= NULL
;
3740 bool migrated
= false;
3742 bool was_writable
= pte_savedwrite(vmf
->orig_pte
);
3746 * The "pte" at this point cannot be used safely without
3747 * validation through pte_unmap_same(). It's of NUMA type but
3748 * the pfn may be screwed if the read is non atomic.
3750 vmf
->ptl
= pte_lockptr(vma
->vm_mm
, vmf
->pmd
);
3751 spin_lock(vmf
->ptl
);
3752 if (unlikely(!pte_same(*vmf
->pte
, vmf
->orig_pte
))) {
3753 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3758 * Make it present again, Depending on how arch implementes non
3759 * accessible ptes, some can allow access by kernel mode.
3761 pte
= ptep_modify_prot_start(vma
->vm_mm
, vmf
->address
, vmf
->pte
);
3762 pte
= pte_modify(pte
, vma
->vm_page_prot
);
3763 pte
= pte_mkyoung(pte
);
3765 pte
= pte_mkwrite(pte
);
3766 ptep_modify_prot_commit(vma
->vm_mm
, vmf
->address
, vmf
->pte
, pte
);
3767 update_mmu_cache(vma
, vmf
->address
, vmf
->pte
);
3769 page
= vm_normal_page(vma
, vmf
->address
, pte
);
3771 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3775 /* TODO: handle PTE-mapped THP */
3776 if (PageCompound(page
)) {
3777 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3782 * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
3783 * much anyway since they can be in shared cache state. This misses
3784 * the case where a mapping is writable but the process never writes
3785 * to it but pte_write gets cleared during protection updates and
3786 * pte_dirty has unpredictable behaviour between PTE scan updates,
3787 * background writeback, dirty balancing and application behaviour.
3789 if (!pte_write(pte
))
3790 flags
|= TNF_NO_GROUP
;
3793 * Flag if the page is shared between multiple address spaces. This
3794 * is later used when determining whether to group tasks together
3796 if (page_mapcount(page
) > 1 && (vma
->vm_flags
& VM_SHARED
))
3797 flags
|= TNF_SHARED
;
3799 last_cpupid
= page_cpupid_last(page
);
3800 page_nid
= page_to_nid(page
);
3801 target_nid
= numa_migrate_prep(page
, vma
, vmf
->address
, page_nid
,
3803 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3804 if (target_nid
== -1) {
3809 /* Migrate to the requested node */
3810 migrated
= migrate_misplaced_page(page
, vma
, target_nid
);
3812 page_nid
= target_nid
;
3813 flags
|= TNF_MIGRATED
;
3815 flags
|= TNF_MIGRATE_FAIL
;
3819 task_numa_fault(last_cpupid
, page_nid
, 1, flags
);
3823 static inline int create_huge_pmd(struct vm_fault
*vmf
)
3825 if (vma_is_anonymous(vmf
->vma
))
3826 return do_huge_pmd_anonymous_page(vmf
);
3827 if (vmf
->vma
->vm_ops
->huge_fault
)
3828 return vmf
->vma
->vm_ops
->huge_fault(vmf
, PE_SIZE_PMD
);
3829 return VM_FAULT_FALLBACK
;
3832 static int wp_huge_pmd(struct vm_fault
*vmf
, pmd_t orig_pmd
)
3834 if (vma_is_anonymous(vmf
->vma
))
3835 return do_huge_pmd_wp_page(vmf
, orig_pmd
);
3836 if (vmf
->vma
->vm_ops
->huge_fault
)
3837 return vmf
->vma
->vm_ops
->huge_fault(vmf
, PE_SIZE_PMD
);
3839 /* COW handled on pte level: split pmd */
3840 VM_BUG_ON_VMA(vmf
->vma
->vm_flags
& VM_SHARED
, vmf
->vma
);
3841 __split_huge_pmd(vmf
->vma
, vmf
->pmd
, vmf
->address
, false, NULL
);
3843 return VM_FAULT_FALLBACK
;
3846 static inline bool vma_is_accessible(struct vm_area_struct
*vma
)
3848 return vma
->vm_flags
& (VM_READ
| VM_EXEC
| VM_WRITE
);
3851 static int create_huge_pud(struct vm_fault
*vmf
)
3853 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3854 /* No support for anonymous transparent PUD pages yet */
3855 if (vma_is_anonymous(vmf
->vma
))
3856 return VM_FAULT_FALLBACK
;
3857 if (vmf
->vma
->vm_ops
->huge_fault
)
3858 return vmf
->vma
->vm_ops
->huge_fault(vmf
, PE_SIZE_PUD
);
3859 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3860 return VM_FAULT_FALLBACK
;
3863 static int wp_huge_pud(struct vm_fault
*vmf
, pud_t orig_pud
)
3865 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3866 /* No support for anonymous transparent PUD pages yet */
3867 if (vma_is_anonymous(vmf
->vma
))
3868 return VM_FAULT_FALLBACK
;
3869 if (vmf
->vma
->vm_ops
->huge_fault
)
3870 return vmf
->vma
->vm_ops
->huge_fault(vmf
, PE_SIZE_PUD
);
3871 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3872 return VM_FAULT_FALLBACK
;
3876 * These routines also need to handle stuff like marking pages dirty
3877 * and/or accessed for architectures that don't do it in hardware (most
3878 * RISC architectures). The early dirtying is also good on the i386.
3880 * There is also a hook called "update_mmu_cache()" that architectures
3881 * with external mmu caches can use to update those (ie the Sparc or
3882 * PowerPC hashed page tables that act as extended TLBs).
3884 * We enter with non-exclusive mmap_sem (to exclude vma changes, but allow
3885 * concurrent faults).
3887 * The mmap_sem may have been released depending on flags and our return value.
3888 * See filemap_fault() and __lock_page_or_retry().
3890 static int handle_pte_fault(struct vm_fault
*vmf
)
3894 if (unlikely(pmd_none(*vmf
->pmd
))) {
3896 * Leave __pte_alloc() until later: because vm_ops->fault may
3897 * want to allocate huge page, and if we expose page table
3898 * for an instant, it will be difficult to retract from
3899 * concurrent faults and from rmap lookups.
3903 /* See comment in pte_alloc_one_map() */
3904 if (pmd_devmap_trans_unstable(vmf
->pmd
))
3907 * A regular pmd is established and it can't morph into a huge
3908 * pmd from under us anymore at this point because we hold the
3909 * mmap_sem read mode and khugepaged takes it in write mode.
3910 * So now it's safe to run pte_offset_map().
3912 vmf
->pte
= pte_offset_map(vmf
->pmd
, vmf
->address
);
3913 vmf
->orig_pte
= *vmf
->pte
;
3916 * some architectures can have larger ptes than wordsize,
3917 * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and
3918 * CONFIG_32BIT=y, so READ_ONCE or ACCESS_ONCE cannot guarantee
3919 * atomic accesses. The code below just needs a consistent
3920 * view for the ifs and we later double check anyway with the
3921 * ptl lock held. So here a barrier will do.
3924 if (pte_none(vmf
->orig_pte
)) {
3925 pte_unmap(vmf
->pte
);
3931 if (vma_is_anonymous(vmf
->vma
))
3932 return do_anonymous_page(vmf
);
3934 return do_fault(vmf
);
3937 if (!pte_present(vmf
->orig_pte
))
3938 return do_swap_page(vmf
);
3940 if (pte_protnone(vmf
->orig_pte
) && vma_is_accessible(vmf
->vma
))
3941 return do_numa_page(vmf
);
3943 vmf
->ptl
= pte_lockptr(vmf
->vma
->vm_mm
, vmf
->pmd
);
3944 spin_lock(vmf
->ptl
);
3945 entry
= vmf
->orig_pte
;
3946 if (unlikely(!pte_same(*vmf
->pte
, entry
)))
3948 if (vmf
->flags
& FAULT_FLAG_WRITE
) {
3949 if (!pte_write(entry
))
3950 return do_wp_page(vmf
);
3951 entry
= pte_mkdirty(entry
);
3953 entry
= pte_mkyoung(entry
);
3954 if (ptep_set_access_flags(vmf
->vma
, vmf
->address
, vmf
->pte
, entry
,
3955 vmf
->flags
& FAULT_FLAG_WRITE
)) {
3956 update_mmu_cache(vmf
->vma
, vmf
->address
, vmf
->pte
);
3959 * This is needed only for protection faults but the arch code
3960 * is not yet telling us if this is a protection fault or not.
3961 * This still avoids useless tlb flushes for .text page faults
3964 if (vmf
->flags
& FAULT_FLAG_WRITE
)
3965 flush_tlb_fix_spurious_fault(vmf
->vma
, vmf
->address
);
3968 pte_unmap_unlock(vmf
->pte
, vmf
->ptl
);
3973 * By the time we get here, we already hold the mm semaphore
3975 * The mmap_sem may have been released depending on flags and our
3976 * return value. See filemap_fault() and __lock_page_or_retry().
3978 static int __handle_mm_fault(struct vm_area_struct
*vma
, unsigned long address
,
3981 struct vm_fault vmf
= {
3983 .address
= address
& PAGE_MASK
,
3985 .pgoff
= linear_page_index(vma
, address
),
3986 .gfp_mask
= __get_fault_gfp_mask(vma
),
3988 unsigned int dirty
= flags
& FAULT_FLAG_WRITE
;
3989 struct mm_struct
*mm
= vma
->vm_mm
;
3994 pgd
= pgd_offset(mm
, address
);
3995 p4d
= p4d_alloc(mm
, pgd
, address
);
3997 return VM_FAULT_OOM
;
3999 vmf
.pud
= pud_alloc(mm
, p4d
, address
);
4001 return VM_FAULT_OOM
;
4002 if (pud_none(*vmf
.pud
) && transparent_hugepage_enabled(vma
)) {
4003 ret
= create_huge_pud(&vmf
);
4004 if (!(ret
& VM_FAULT_FALLBACK
))
4007 pud_t orig_pud
= *vmf
.pud
;
4010 if (pud_trans_huge(orig_pud
) || pud_devmap(orig_pud
)) {
4012 /* NUMA case for anonymous PUDs would go here */
4014 if (dirty
&& !pud_write(orig_pud
)) {
4015 ret
= wp_huge_pud(&vmf
, orig_pud
);
4016 if (!(ret
& VM_FAULT_FALLBACK
))
4019 huge_pud_set_accessed(&vmf
, orig_pud
);
4025 vmf
.pmd
= pmd_alloc(mm
, vmf
.pud
, address
);
4027 return VM_FAULT_OOM
;
4028 if (pmd_none(*vmf
.pmd
) && transparent_hugepage_enabled(vma
)) {
4029 ret
= create_huge_pmd(&vmf
);
4030 if (!(ret
& VM_FAULT_FALLBACK
))
4033 pmd_t orig_pmd
= *vmf
.pmd
;
4036 if (unlikely(is_swap_pmd(orig_pmd
))) {
4037 VM_BUG_ON(thp_migration_supported() &&
4038 !is_pmd_migration_entry(orig_pmd
));
4039 if (is_pmd_migration_entry(orig_pmd
))
4040 pmd_migration_entry_wait(mm
, vmf
.pmd
);
4043 if (pmd_trans_huge(orig_pmd
) || pmd_devmap(orig_pmd
)) {
4044 if (pmd_protnone(orig_pmd
) && vma_is_accessible(vma
))
4045 return do_huge_pmd_numa_page(&vmf
, orig_pmd
);
4047 if (dirty
&& !pmd_write(orig_pmd
)) {
4048 ret
= wp_huge_pmd(&vmf
, orig_pmd
);
4049 if (!(ret
& VM_FAULT_FALLBACK
))
4052 huge_pmd_set_accessed(&vmf
, orig_pmd
);
4058 return handle_pte_fault(&vmf
);
4062 * By the time we get here, we already hold the mm semaphore
4064 * The mmap_sem may have been released depending on flags and our
4065 * return value. See filemap_fault() and __lock_page_or_retry().
4067 int handle_mm_fault(struct vm_area_struct
*vma
, unsigned long address
,
4072 __set_current_state(TASK_RUNNING
);
4074 count_vm_event(PGFAULT
);
4075 count_memcg_event_mm(vma
->vm_mm
, PGFAULT
);
4077 /* do counter updates before entering really critical section. */
4078 check_sync_rss_stat(current
);
4080 if (!arch_vma_access_permitted(vma
, flags
& FAULT_FLAG_WRITE
,
4081 flags
& FAULT_FLAG_INSTRUCTION
,
4082 flags
& FAULT_FLAG_REMOTE
))
4083 return VM_FAULT_SIGSEGV
;
4086 * Enable the memcg OOM handling for faults triggered in user
4087 * space. Kernel faults are handled more gracefully.
4089 if (flags
& FAULT_FLAG_USER
)
4090 mem_cgroup_oom_enable();
4092 if (unlikely(is_vm_hugetlb_page(vma
)))
4093 ret
= hugetlb_fault(vma
->vm_mm
, vma
, address
, flags
);
4095 ret
= __handle_mm_fault(vma
, address
, flags
);
4097 if (flags
& FAULT_FLAG_USER
) {
4098 mem_cgroup_oom_disable();
4100 * The task may have entered a memcg OOM situation but
4101 * if the allocation error was handled gracefully (no
4102 * VM_FAULT_OOM), there is no need to kill anything.
4103 * Just clean up the OOM state peacefully.
4105 if (task_in_memcg_oom(current
) && !(ret
& VM_FAULT_OOM
))
4106 mem_cgroup_oom_synchronize(false);
4111 EXPORT_SYMBOL_GPL(handle_mm_fault
);
4113 #ifndef __PAGETABLE_P4D_FOLDED
4115 * Allocate p4d page table.
4116 * We've already handled the fast-path in-line.
4118 int __p4d_alloc(struct mm_struct
*mm
, pgd_t
*pgd
, unsigned long address
)
4120 p4d_t
*new = p4d_alloc_one(mm
, address
);
4124 smp_wmb(); /* See comment in __pte_alloc */
4126 spin_lock(&mm
->page_table_lock
);
4127 if (pgd_present(*pgd
)) /* Another has populated it */
4130 pgd_populate(mm
, pgd
, new);
4131 spin_unlock(&mm
->page_table_lock
);
4134 #endif /* __PAGETABLE_P4D_FOLDED */
4136 #ifndef __PAGETABLE_PUD_FOLDED
4138 * Allocate page upper directory.
4139 * We've already handled the fast-path in-line.
4141 int __pud_alloc(struct mm_struct
*mm
, p4d_t
*p4d
, unsigned long address
)
4143 pud_t
*new = pud_alloc_one(mm
, address
);
4147 smp_wmb(); /* See comment in __pte_alloc */
4149 spin_lock(&mm
->page_table_lock
);
4150 #ifndef __ARCH_HAS_5LEVEL_HACK
4151 if (p4d_present(*p4d
)) /* Another has populated it */
4154 p4d_populate(mm
, p4d
, new);
4156 if (pgd_present(*p4d
)) /* Another has populated it */
4159 pgd_populate(mm
, p4d
, new);
4160 #endif /* __ARCH_HAS_5LEVEL_HACK */
4161 spin_unlock(&mm
->page_table_lock
);
4164 #endif /* __PAGETABLE_PUD_FOLDED */
4166 #ifndef __PAGETABLE_PMD_FOLDED
4168 * Allocate page middle directory.
4169 * We've already handled the fast-path in-line.
4171 int __pmd_alloc(struct mm_struct
*mm
, pud_t
*pud
, unsigned long address
)
4174 pmd_t
*new = pmd_alloc_one(mm
, address
);
4178 smp_wmb(); /* See comment in __pte_alloc */
4180 ptl
= pud_lock(mm
, pud
);
4181 #ifndef __ARCH_HAS_4LEVEL_HACK
4182 if (!pud_present(*pud
)) {
4184 pud_populate(mm
, pud
, new);
4185 } else /* Another has populated it */
4188 if (!pgd_present(*pud
)) {
4190 pgd_populate(mm
, pud
, new);
4191 } else /* Another has populated it */
4193 #endif /* __ARCH_HAS_4LEVEL_HACK */
4197 #endif /* __PAGETABLE_PMD_FOLDED */
4199 static int __follow_pte_pmd(struct mm_struct
*mm
, unsigned long address
,
4200 unsigned long *start
, unsigned long *end
,
4201 pte_t
**ptepp
, pmd_t
**pmdpp
, spinlock_t
**ptlp
)
4209 pgd
= pgd_offset(mm
, address
);
4210 if (pgd_none(*pgd
) || unlikely(pgd_bad(*pgd
)))
4213 p4d
= p4d_offset(pgd
, address
);
4214 if (p4d_none(*p4d
) || unlikely(p4d_bad(*p4d
)))
4217 pud
= pud_offset(p4d
, address
);
4218 if (pud_none(*pud
) || unlikely(pud_bad(*pud
)))
4221 pmd
= pmd_offset(pud
, address
);
4222 VM_BUG_ON(pmd_trans_huge(*pmd
));
4224 if (pmd_huge(*pmd
)) {
4229 *start
= address
& PMD_MASK
;
4230 *end
= *start
+ PMD_SIZE
;
4231 mmu_notifier_invalidate_range_start(mm
, *start
, *end
);
4233 *ptlp
= pmd_lock(mm
, pmd
);
4234 if (pmd_huge(*pmd
)) {
4240 mmu_notifier_invalidate_range_end(mm
, *start
, *end
);
4243 if (pmd_none(*pmd
) || unlikely(pmd_bad(*pmd
)))
4247 *start
= address
& PAGE_MASK
;
4248 *end
= *start
+ PAGE_SIZE
;
4249 mmu_notifier_invalidate_range_start(mm
, *start
, *end
);
4251 ptep
= pte_offset_map_lock(mm
, pmd
, address
, ptlp
);
4252 if (!pte_present(*ptep
))
4257 pte_unmap_unlock(ptep
, *ptlp
);
4259 mmu_notifier_invalidate_range_end(mm
, *start
, *end
);
4264 static inline int follow_pte(struct mm_struct
*mm
, unsigned long address
,
4265 pte_t
**ptepp
, spinlock_t
**ptlp
)
4269 /* (void) is needed to make gcc happy */
4270 (void) __cond_lock(*ptlp
,
4271 !(res
= __follow_pte_pmd(mm
, address
, NULL
, NULL
,
4272 ptepp
, NULL
, ptlp
)));
4276 int follow_pte_pmd(struct mm_struct
*mm
, unsigned long address
,
4277 unsigned long *start
, unsigned long *end
,
4278 pte_t
**ptepp
, pmd_t
**pmdpp
, spinlock_t
**ptlp
)
4282 /* (void) is needed to make gcc happy */
4283 (void) __cond_lock(*ptlp
,
4284 !(res
= __follow_pte_pmd(mm
, address
, start
, end
,
4285 ptepp
, pmdpp
, ptlp
)));
4288 EXPORT_SYMBOL(follow_pte_pmd
);
4291 * follow_pfn - look up PFN at a user virtual address
4292 * @vma: memory mapping
4293 * @address: user virtual address
4294 * @pfn: location to store found PFN
4296 * Only IO mappings and raw PFN mappings are allowed.
4298 * Returns zero and the pfn at @pfn on success, -ve otherwise.
4300 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
4307 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
4310 ret
= follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
);
4313 *pfn
= pte_pfn(*ptep
);
4314 pte_unmap_unlock(ptep
, ptl
);
4317 EXPORT_SYMBOL(follow_pfn
);
4319 #ifdef CONFIG_HAVE_IOREMAP_PROT
4320 int follow_phys(struct vm_area_struct
*vma
,
4321 unsigned long address
, unsigned int flags
,
4322 unsigned long *prot
, resource_size_t
*phys
)
4328 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
4331 if (follow_pte(vma
->vm_mm
, address
, &ptep
, &ptl
))
4335 if ((flags
& FOLL_WRITE
) && !pte_write(pte
))
4338 *prot
= pgprot_val(pte_pgprot(pte
));
4339 *phys
= (resource_size_t
)pte_pfn(pte
) << PAGE_SHIFT
;
4343 pte_unmap_unlock(ptep
, ptl
);
4348 int generic_access_phys(struct vm_area_struct
*vma
, unsigned long addr
,
4349 void *buf
, int len
, int write
)
4351 resource_size_t phys_addr
;
4352 unsigned long prot
= 0;
4353 void __iomem
*maddr
;
4354 int offset
= addr
& (PAGE_SIZE
-1);
4356 if (follow_phys(vma
, addr
, write
, &prot
, &phys_addr
))
4359 maddr
= ioremap_prot(phys_addr
, PAGE_ALIGN(len
+ offset
), prot
);
4364 memcpy_toio(maddr
+ offset
, buf
, len
);
4366 memcpy_fromio(buf
, maddr
+ offset
, len
);
4371 EXPORT_SYMBOL_GPL(generic_access_phys
);
4375 * Access another process' address space as given in mm. If non-NULL, use the
4376 * given task for page fault accounting.
4378 int __access_remote_vm(struct task_struct
*tsk
, struct mm_struct
*mm
,
4379 unsigned long addr
, void *buf
, int len
, unsigned int gup_flags
)
4381 struct vm_area_struct
*vma
;
4382 void *old_buf
= buf
;
4383 int write
= gup_flags
& FOLL_WRITE
;
4385 down_read(&mm
->mmap_sem
);
4386 /* ignore errors, just check how much was successfully transferred */
4388 int bytes
, ret
, offset
;
4390 struct page
*page
= NULL
;
4392 ret
= get_user_pages_remote(tsk
, mm
, addr
, 1,
4393 gup_flags
, &page
, &vma
, NULL
);
4395 #ifndef CONFIG_HAVE_IOREMAP_PROT
4399 * Check if this is a VM_IO | VM_PFNMAP VMA, which
4400 * we can access using slightly different code.
4402 vma
= find_vma(mm
, addr
);
4403 if (!vma
|| vma
->vm_start
> addr
)
4405 if (vma
->vm_ops
&& vma
->vm_ops
->access
)
4406 ret
= vma
->vm_ops
->access(vma
, addr
, buf
,
4414 offset
= addr
& (PAGE_SIZE
-1);
4415 if (bytes
> PAGE_SIZE
-offset
)
4416 bytes
= PAGE_SIZE
-offset
;
4420 copy_to_user_page(vma
, page
, addr
,
4421 maddr
+ offset
, buf
, bytes
);
4422 set_page_dirty_lock(page
);
4424 copy_from_user_page(vma
, page
, addr
,
4425 buf
, maddr
+ offset
, bytes
);
4434 up_read(&mm
->mmap_sem
);
4436 return buf
- old_buf
;
4440 * access_remote_vm - access another process' address space
4441 * @mm: the mm_struct of the target address space
4442 * @addr: start address to access
4443 * @buf: source or destination buffer
4444 * @len: number of bytes to transfer
4445 * @gup_flags: flags modifying lookup behaviour
4447 * The caller must hold a reference on @mm.
4449 int access_remote_vm(struct mm_struct
*mm
, unsigned long addr
,
4450 void *buf
, int len
, unsigned int gup_flags
)
4452 return __access_remote_vm(NULL
, mm
, addr
, buf
, len
, gup_flags
);
4456 * Access another process' address space.
4457 * Source/target buffer must be kernel space,
4458 * Do not walk the page table directly, use get_user_pages
4460 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
,
4461 void *buf
, int len
, unsigned int gup_flags
)
4463 struct mm_struct
*mm
;
4466 mm
= get_task_mm(tsk
);
4470 ret
= __access_remote_vm(tsk
, mm
, addr
, buf
, len
, gup_flags
);
4476 EXPORT_SYMBOL_GPL(access_process_vm
);
4479 * Print the name of a VMA.
4481 void print_vma_addr(char *prefix
, unsigned long ip
)
4483 struct mm_struct
*mm
= current
->mm
;
4484 struct vm_area_struct
*vma
;
4487 * Do not print if we are in atomic
4488 * contexts (in exception stacks, etc.):
4490 if (preempt_count())
4493 down_read(&mm
->mmap_sem
);
4494 vma
= find_vma(mm
, ip
);
4495 if (vma
&& vma
->vm_file
) {
4496 struct file
*f
= vma
->vm_file
;
4497 char *buf
= (char *)__get_free_page(GFP_KERNEL
);
4501 p
= file_path(f
, buf
, PAGE_SIZE
);
4504 printk("%s%s[%lx+%lx]", prefix
, kbasename(p
),
4506 vma
->vm_end
- vma
->vm_start
);
4507 free_page((unsigned long)buf
);
4510 up_read(&mm
->mmap_sem
);
4513 #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
4514 void __might_fault(const char *file
, int line
)
4517 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4518 * holding the mmap_sem, this is safe because kernel memory doesn't
4519 * get paged out, therefore we'll never actually fault, and the
4520 * below annotations will generate false positives.
4522 if (uaccess_kernel())
4524 if (pagefault_disabled())
4526 __might_sleep(file
, line
, 0);
4527 #if defined(CONFIG_DEBUG_ATOMIC_SLEEP)
4529 might_lock_read(¤t
->mm
->mmap_sem
);
4532 EXPORT_SYMBOL(__might_fault
);
4535 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4536 static void clear_gigantic_page(struct page
*page
,
4538 unsigned int pages_per_huge_page
)
4541 struct page
*p
= page
;
4544 for (i
= 0; i
< pages_per_huge_page
;
4545 i
++, p
= mem_map_next(p
, page
, i
)) {
4547 clear_user_highpage(p
, addr
+ i
* PAGE_SIZE
);
4550 void clear_huge_page(struct page
*page
,
4551 unsigned long addr_hint
, unsigned int pages_per_huge_page
)
4554 unsigned long addr
= addr_hint
&
4555 ~(((unsigned long)pages_per_huge_page
<< PAGE_SHIFT
) - 1);
4557 if (unlikely(pages_per_huge_page
> MAX_ORDER_NR_PAGES
)) {
4558 clear_gigantic_page(page
, addr
, pages_per_huge_page
);
4562 /* Clear sub-page to access last to keep its cache lines hot */
4564 n
= (addr_hint
- addr
) / PAGE_SIZE
;
4565 if (2 * n
<= pages_per_huge_page
) {
4566 /* If sub-page to access in first half of huge page */
4569 /* Clear sub-pages at the end of huge page */
4570 for (i
= pages_per_huge_page
- 1; i
>= 2 * n
; i
--) {
4572 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
4575 /* If sub-page to access in second half of huge page */
4576 base
= pages_per_huge_page
- 2 * (pages_per_huge_page
- n
);
4577 l
= pages_per_huge_page
- n
;
4578 /* Clear sub-pages at the begin of huge page */
4579 for (i
= 0; i
< base
; i
++) {
4581 clear_user_highpage(page
+ i
, addr
+ i
* PAGE_SIZE
);
4585 * Clear remaining sub-pages in left-right-left-right pattern
4586 * towards the sub-page to access
4588 for (i
= 0; i
< l
; i
++) {
4589 int left_idx
= base
+ i
;
4590 int right_idx
= base
+ 2 * l
- 1 - i
;
4593 clear_user_highpage(page
+ left_idx
,
4594 addr
+ left_idx
* PAGE_SIZE
);
4596 clear_user_highpage(page
+ right_idx
,
4597 addr
+ right_idx
* PAGE_SIZE
);
4601 static void copy_user_gigantic_page(struct page
*dst
, struct page
*src
,
4603 struct vm_area_struct
*vma
,
4604 unsigned int pages_per_huge_page
)
4607 struct page
*dst_base
= dst
;
4608 struct page
*src_base
= src
;
4610 for (i
= 0; i
< pages_per_huge_page
; ) {
4612 copy_user_highpage(dst
, src
, addr
+ i
*PAGE_SIZE
, vma
);
4615 dst
= mem_map_next(dst
, dst_base
, i
);
4616 src
= mem_map_next(src
, src_base
, i
);
4620 void copy_user_huge_page(struct page
*dst
, struct page
*src
,
4621 unsigned long addr
, struct vm_area_struct
*vma
,
4622 unsigned int pages_per_huge_page
)
4626 if (unlikely(pages_per_huge_page
> MAX_ORDER_NR_PAGES
)) {
4627 copy_user_gigantic_page(dst
, src
, addr
, vma
,
4628 pages_per_huge_page
);
4633 for (i
= 0; i
< pages_per_huge_page
; i
++) {
4635 copy_user_highpage(dst
+ i
, src
+ i
, addr
+ i
*PAGE_SIZE
, vma
);
4639 long copy_huge_page_from_user(struct page
*dst_page
,
4640 const void __user
*usr_src
,
4641 unsigned int pages_per_huge_page
,
4642 bool allow_pagefault
)
4644 void *src
= (void *)usr_src
;
4646 unsigned long i
, rc
= 0;
4647 unsigned long ret_val
= pages_per_huge_page
* PAGE_SIZE
;
4649 for (i
= 0; i
< pages_per_huge_page
; i
++) {
4650 if (allow_pagefault
)
4651 page_kaddr
= kmap(dst_page
+ i
);
4653 page_kaddr
= kmap_atomic(dst_page
+ i
);
4654 rc
= copy_from_user(page_kaddr
,
4655 (const void __user
*)(src
+ i
* PAGE_SIZE
),
4657 if (allow_pagefault
)
4658 kunmap(dst_page
+ i
);
4660 kunmap_atomic(page_kaddr
);
4662 ret_val
-= (PAGE_SIZE
- rc
);
4670 #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
4672 #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
4674 static struct kmem_cache
*page_ptl_cachep
;
4676 void __init
ptlock_cache_init(void)
4678 page_ptl_cachep
= kmem_cache_create("page->ptl", sizeof(spinlock_t
), 0,
4682 bool ptlock_alloc(struct page
*page
)
4686 ptl
= kmem_cache_alloc(page_ptl_cachep
, GFP_KERNEL
);
4693 void ptlock_free(struct page
*page
)
4695 kmem_cache_free(page_ptl_cachep
, page
->ptl
);