4 * Replacement code for mm functions to support CPU's that don't
5 * have any form of memory management unit (thus no virtual memory).
7 * See Documentation/nommu-mmap.txt
9 * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
10 * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
11 * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
12 * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
13 * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
16 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18 #include <linux/export.h>
20 #include <linux/vmacache.h>
21 #include <linux/mman.h>
22 #include <linux/swap.h>
23 #include <linux/file.h>
24 #include <linux/highmem.h>
25 #include <linux/pagemap.h>
26 #include <linux/slab.h>
27 #include <linux/vmalloc.h>
28 #include <linux/blkdev.h>
29 #include <linux/backing-dev.h>
30 #include <linux/compiler.h>
31 #include <linux/mount.h>
32 #include <linux/personality.h>
33 #include <linux/security.h>
34 #include <linux/syscalls.h>
35 #include <linux/audit.h>
36 #include <linux/printk.h>
38 #include <asm/uaccess.h>
40 #include <asm/tlbflush.h>
41 #include <asm/mmu_context.h>
45 EXPORT_SYMBOL(high_memory
);
47 unsigned long max_mapnr
;
48 EXPORT_SYMBOL(max_mapnr
);
49 unsigned long highest_memmap_pfn
;
50 int sysctl_nr_trim_pages
= CONFIG_NOMMU_INITIAL_TRIM_EXCESS
;
51 int heap_stack_gap
= 0;
53 atomic_long_t mmap_pages_allocated
;
55 EXPORT_SYMBOL(mem_map
);
57 /* list of mapped, potentially shareable regions */
58 static struct kmem_cache
*vm_region_jar
;
59 struct rb_root nommu_region_tree
= RB_ROOT
;
60 DECLARE_RWSEM(nommu_region_sem
);
62 const struct vm_operations_struct generic_file_vm_ops
= {
66 * Return the total memory allocated for this pointer, not
67 * just what the caller asked for.
69 * Doesn't have to be accurate, i.e. may have races.
71 unsigned int kobjsize(const void *objp
)
76 * If the object we have should not have ksize performed on it,
79 if (!objp
|| !virt_addr_valid(objp
))
82 page
= virt_to_head_page(objp
);
85 * If the allocator sets PageSlab, we know the pointer came from
92 * If it's not a compound page, see if we have a matching VMA
93 * region. This test is intentionally done in reverse order,
94 * so if there's no VMA, we still fall through and hand back
95 * PAGE_SIZE for 0-order pages.
97 if (!PageCompound(page
)) {
98 struct vm_area_struct
*vma
;
100 vma
= find_vma(current
->mm
, (unsigned long)objp
);
102 return vma
->vm_end
- vma
->vm_start
;
106 * The ksize() function is only guaranteed to work for pointers
107 * returned by kmalloc(). So handle arbitrary pointers here.
109 return PAGE_SIZE
<< compound_order(page
);
112 long __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
113 unsigned long start
, unsigned long nr_pages
,
114 unsigned int foll_flags
, struct page
**pages
,
115 struct vm_area_struct
**vmas
, int *nonblocking
)
117 struct vm_area_struct
*vma
;
118 unsigned long vm_flags
;
121 /* calculate required read or write permissions.
122 * If FOLL_FORCE is set, we only require the "MAY" flags.
124 vm_flags
= (foll_flags
& FOLL_WRITE
) ?
125 (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
126 vm_flags
&= (foll_flags
& FOLL_FORCE
) ?
127 (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
129 for (i
= 0; i
< nr_pages
; i
++) {
130 vma
= find_vma(mm
, start
);
132 goto finish_or_fault
;
134 /* protect what we can, including chardevs */
135 if ((vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
136 !(vm_flags
& vma
->vm_flags
))
137 goto finish_or_fault
;
140 pages
[i
] = virt_to_page(start
);
142 page_cache_get(pages
[i
]);
146 start
= (start
+ PAGE_SIZE
) & PAGE_MASK
;
152 return i
? : -EFAULT
;
156 * get a list of pages in an address range belonging to the specified process
157 * and indicate the VMA that covers each page
158 * - this is potentially dodgy as we may end incrementing the page count of a
159 * slab page or a secondary page from a compound page
160 * - don't permit access to VMAs that don't support it, such as I/O mappings
162 long get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
163 unsigned long start
, unsigned long nr_pages
,
164 int write
, int force
, struct page
**pages
,
165 struct vm_area_struct
**vmas
)
174 return __get_user_pages(tsk
, mm
, start
, nr_pages
, flags
, pages
, vmas
,
177 EXPORT_SYMBOL(get_user_pages
);
179 long get_user_pages_locked(struct task_struct
*tsk
, struct mm_struct
*mm
,
180 unsigned long start
, unsigned long nr_pages
,
181 int write
, int force
, struct page
**pages
,
184 return get_user_pages(tsk
, mm
, start
, nr_pages
, write
, force
,
187 EXPORT_SYMBOL(get_user_pages_locked
);
189 long __get_user_pages_unlocked(struct task_struct
*tsk
, struct mm_struct
*mm
,
190 unsigned long start
, unsigned long nr_pages
,
191 int write
, int force
, struct page
**pages
,
192 unsigned int gup_flags
)
195 down_read(&mm
->mmap_sem
);
196 ret
= get_user_pages(tsk
, mm
, start
, nr_pages
, write
, force
,
198 up_read(&mm
->mmap_sem
);
201 EXPORT_SYMBOL(__get_user_pages_unlocked
);
203 long get_user_pages_unlocked(struct task_struct
*tsk
, struct mm_struct
*mm
,
204 unsigned long start
, unsigned long nr_pages
,
205 int write
, int force
, struct page
**pages
)
207 return __get_user_pages_unlocked(tsk
, mm
, start
, nr_pages
, write
,
210 EXPORT_SYMBOL(get_user_pages_unlocked
);
213 * follow_pfn - look up PFN at a user virtual address
214 * @vma: memory mapping
215 * @address: user virtual address
216 * @pfn: location to store found PFN
218 * Only IO mappings and raw PFN mappings are allowed.
220 * Returns zero and the pfn at @pfn on success, -ve otherwise.
222 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
225 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
228 *pfn
= address
>> PAGE_SHIFT
;
231 EXPORT_SYMBOL(follow_pfn
);
233 LIST_HEAD(vmap_area_list
);
235 void vfree(const void *addr
)
239 EXPORT_SYMBOL(vfree
);
241 void *__vmalloc(unsigned long size
, gfp_t gfp_mask
, pgprot_t prot
)
244 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
245 * returns only a logical address.
247 return kmalloc(size
, (gfp_mask
| __GFP_COMP
) & ~__GFP_HIGHMEM
);
249 EXPORT_SYMBOL(__vmalloc
);
251 void *vmalloc_user(unsigned long size
)
255 ret
= __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
| __GFP_ZERO
,
258 struct vm_area_struct
*vma
;
260 down_write(¤t
->mm
->mmap_sem
);
261 vma
= find_vma(current
->mm
, (unsigned long)ret
);
263 vma
->vm_flags
|= VM_USERMAP
;
264 up_write(¤t
->mm
->mmap_sem
);
269 EXPORT_SYMBOL(vmalloc_user
);
271 struct page
*vmalloc_to_page(const void *addr
)
273 return virt_to_page(addr
);
275 EXPORT_SYMBOL(vmalloc_to_page
);
277 unsigned long vmalloc_to_pfn(const void *addr
)
279 return page_to_pfn(virt_to_page(addr
));
281 EXPORT_SYMBOL(vmalloc_to_pfn
);
283 long vread(char *buf
, char *addr
, unsigned long count
)
285 /* Don't allow overflow */
286 if ((unsigned long) buf
+ count
< count
)
287 count
= -(unsigned long) buf
;
289 memcpy(buf
, addr
, count
);
293 long vwrite(char *buf
, char *addr
, unsigned long count
)
295 /* Don't allow overflow */
296 if ((unsigned long) addr
+ count
< count
)
297 count
= -(unsigned long) addr
;
299 memcpy(addr
, buf
, count
);
304 * vmalloc - allocate virtually contiguous memory
306 * @size: allocation size
308 * Allocate enough pages to cover @size from the page level
309 * allocator and map them into contiguous kernel virtual space.
311 * For tight control over page level allocator and protection flags
312 * use __vmalloc() instead.
314 void *vmalloc(unsigned long size
)
316 return __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
, PAGE_KERNEL
);
318 EXPORT_SYMBOL(vmalloc
);
321 * vzalloc - allocate virtually contiguous memory with zero fill
323 * @size: allocation size
325 * Allocate enough pages to cover @size from the page level
326 * allocator and map them into contiguous kernel virtual space.
327 * The memory allocated is set to zero.
329 * For tight control over page level allocator and protection flags
330 * use __vmalloc() instead.
332 void *vzalloc(unsigned long size
)
334 return __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
| __GFP_ZERO
,
337 EXPORT_SYMBOL(vzalloc
);
340 * vmalloc_node - allocate memory on a specific node
341 * @size: allocation size
344 * Allocate enough pages to cover @size from the page level
345 * allocator and map them into contiguous kernel virtual space.
347 * For tight control over page level allocator and protection flags
348 * use __vmalloc() instead.
350 void *vmalloc_node(unsigned long size
, int node
)
352 return vmalloc(size
);
354 EXPORT_SYMBOL(vmalloc_node
);
357 * vzalloc_node - allocate memory on a specific node with zero fill
358 * @size: allocation size
361 * Allocate enough pages to cover @size from the page level
362 * allocator and map them into contiguous kernel virtual space.
363 * The memory allocated is set to zero.
365 * For tight control over page level allocator and protection flags
366 * use __vmalloc() instead.
368 void *vzalloc_node(unsigned long size
, int node
)
370 return vzalloc(size
);
372 EXPORT_SYMBOL(vzalloc_node
);
374 #ifndef PAGE_KERNEL_EXEC
375 # define PAGE_KERNEL_EXEC PAGE_KERNEL
379 * vmalloc_exec - allocate virtually contiguous, executable memory
380 * @size: allocation size
382 * Kernel-internal function to allocate enough pages to cover @size
383 * the page level allocator and map them into contiguous and
384 * executable kernel virtual space.
386 * For tight control over page level allocator and protection flags
387 * use __vmalloc() instead.
390 void *vmalloc_exec(unsigned long size
)
392 return __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
, PAGE_KERNEL_EXEC
);
396 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
397 * @size: allocation size
399 * Allocate enough 32bit PA addressable pages to cover @size from the
400 * page level allocator and map them into contiguous kernel virtual space.
402 void *vmalloc_32(unsigned long size
)
404 return __vmalloc(size
, GFP_KERNEL
, PAGE_KERNEL
);
406 EXPORT_SYMBOL(vmalloc_32
);
409 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
410 * @size: allocation size
412 * The resulting memory area is 32bit addressable and zeroed so it can be
413 * mapped to userspace without leaking data.
415 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
416 * remap_vmalloc_range() are permissible.
418 void *vmalloc_32_user(unsigned long size
)
421 * We'll have to sort out the ZONE_DMA bits for 64-bit,
422 * but for now this can simply use vmalloc_user() directly.
424 return vmalloc_user(size
);
426 EXPORT_SYMBOL(vmalloc_32_user
);
428 void *vmap(struct page
**pages
, unsigned int count
, unsigned long flags
, pgprot_t prot
)
435 void vunmap(const void *addr
)
439 EXPORT_SYMBOL(vunmap
);
441 void *vm_map_ram(struct page
**pages
, unsigned int count
, int node
, pgprot_t prot
)
446 EXPORT_SYMBOL(vm_map_ram
);
448 void vm_unmap_ram(const void *mem
, unsigned int count
)
452 EXPORT_SYMBOL(vm_unmap_ram
);
454 void vm_unmap_aliases(void)
457 EXPORT_SYMBOL_GPL(vm_unmap_aliases
);
460 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
463 void __weak
vmalloc_sync_all(void)
468 * alloc_vm_area - allocate a range of kernel address space
469 * @size: size of the area
471 * Returns: NULL on failure, vm_struct on success
473 * This function reserves a range of kernel address space, and
474 * allocates pagetables to map that range. No actual mappings
475 * are created. If the kernel address space is not shared
476 * between processes, it syncs the pagetable across all
479 struct vm_struct
*alloc_vm_area(size_t size
, pte_t
**ptes
)
484 EXPORT_SYMBOL_GPL(alloc_vm_area
);
486 void free_vm_area(struct vm_struct
*area
)
490 EXPORT_SYMBOL_GPL(free_vm_area
);
492 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
497 EXPORT_SYMBOL(vm_insert_page
);
500 * sys_brk() for the most part doesn't need the global kernel
501 * lock, except when an application is doing something nasty
502 * like trying to un-brk an area that has already been mapped
503 * to a regular file. in this case, the unmapping will need
504 * to invoke file system routines that need the global lock.
506 SYSCALL_DEFINE1(brk
, unsigned long, brk
)
508 struct mm_struct
*mm
= current
->mm
;
510 if (brk
< mm
->start_brk
|| brk
> mm
->context
.end_brk
)
517 * Always allow shrinking brk
519 if (brk
<= mm
->brk
) {
525 * Ok, looks good - let it rip.
527 flush_icache_range(mm
->brk
, brk
);
528 return mm
->brk
= brk
;
532 * initialise the VMA and region record slabs
534 void __init
mmap_init(void)
538 ret
= percpu_counter_init(&vm_committed_as
, 0, GFP_KERNEL
);
540 vm_region_jar
= KMEM_CACHE(vm_region
, SLAB_PANIC
|SLAB_ACCOUNT
);
544 * validate the region tree
545 * - the caller must hold the region lock
547 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
548 static noinline
void validate_nommu_regions(void)
550 struct vm_region
*region
, *last
;
551 struct rb_node
*p
, *lastp
;
553 lastp
= rb_first(&nommu_region_tree
);
557 last
= rb_entry(lastp
, struct vm_region
, vm_rb
);
558 BUG_ON(last
->vm_end
<= last
->vm_start
);
559 BUG_ON(last
->vm_top
< last
->vm_end
);
561 while ((p
= rb_next(lastp
))) {
562 region
= rb_entry(p
, struct vm_region
, vm_rb
);
563 last
= rb_entry(lastp
, struct vm_region
, vm_rb
);
565 BUG_ON(region
->vm_end
<= region
->vm_start
);
566 BUG_ON(region
->vm_top
< region
->vm_end
);
567 BUG_ON(region
->vm_start
< last
->vm_top
);
573 static void validate_nommu_regions(void)
579 * add a region into the global tree
581 static void add_nommu_region(struct vm_region
*region
)
583 struct vm_region
*pregion
;
584 struct rb_node
**p
, *parent
;
586 validate_nommu_regions();
589 p
= &nommu_region_tree
.rb_node
;
592 pregion
= rb_entry(parent
, struct vm_region
, vm_rb
);
593 if (region
->vm_start
< pregion
->vm_start
)
595 else if (region
->vm_start
> pregion
->vm_start
)
597 else if (pregion
== region
)
603 rb_link_node(®ion
->vm_rb
, parent
, p
);
604 rb_insert_color(®ion
->vm_rb
, &nommu_region_tree
);
606 validate_nommu_regions();
610 * delete a region from the global tree
612 static void delete_nommu_region(struct vm_region
*region
)
614 BUG_ON(!nommu_region_tree
.rb_node
);
616 validate_nommu_regions();
617 rb_erase(®ion
->vm_rb
, &nommu_region_tree
);
618 validate_nommu_regions();
622 * free a contiguous series of pages
624 static void free_page_series(unsigned long from
, unsigned long to
)
626 for (; from
< to
; from
+= PAGE_SIZE
) {
627 struct page
*page
= virt_to_page(from
);
629 atomic_long_dec(&mmap_pages_allocated
);
635 * release a reference to a region
636 * - the caller must hold the region semaphore for writing, which this releases
637 * - the region may not have been added to the tree yet, in which case vm_top
638 * will equal vm_start
640 static void __put_nommu_region(struct vm_region
*region
)
641 __releases(nommu_region_sem
)
643 BUG_ON(!nommu_region_tree
.rb_node
);
645 if (--region
->vm_usage
== 0) {
646 if (region
->vm_top
> region
->vm_start
)
647 delete_nommu_region(region
);
648 up_write(&nommu_region_sem
);
651 fput(region
->vm_file
);
653 /* IO memory and memory shared directly out of the pagecache
654 * from ramfs/tmpfs mustn't be released here */
655 if (region
->vm_flags
& VM_MAPPED_COPY
)
656 free_page_series(region
->vm_start
, region
->vm_top
);
657 kmem_cache_free(vm_region_jar
, region
);
659 up_write(&nommu_region_sem
);
664 * release a reference to a region
666 static void put_nommu_region(struct vm_region
*region
)
668 down_write(&nommu_region_sem
);
669 __put_nommu_region(region
);
673 * update protection on a vma
675 static void protect_vma(struct vm_area_struct
*vma
, unsigned long flags
)
678 struct mm_struct
*mm
= vma
->vm_mm
;
679 long start
= vma
->vm_start
& PAGE_MASK
;
680 while (start
< vma
->vm_end
) {
681 protect_page(mm
, start
, flags
);
684 update_protections(mm
);
689 * add a VMA into a process's mm_struct in the appropriate place in the list
690 * and tree and add to the address space's page tree also if not an anonymous
692 * - should be called with mm->mmap_sem held writelocked
694 static void add_vma_to_mm(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
696 struct vm_area_struct
*pvma
, *prev
;
697 struct address_space
*mapping
;
698 struct rb_node
**p
, *parent
, *rb_prev
;
700 BUG_ON(!vma
->vm_region
);
705 protect_vma(vma
, vma
->vm_flags
);
707 /* add the VMA to the mapping */
709 mapping
= vma
->vm_file
->f_mapping
;
711 i_mmap_lock_write(mapping
);
712 flush_dcache_mmap_lock(mapping
);
713 vma_interval_tree_insert(vma
, &mapping
->i_mmap
);
714 flush_dcache_mmap_unlock(mapping
);
715 i_mmap_unlock_write(mapping
);
718 /* add the VMA to the tree */
719 parent
= rb_prev
= NULL
;
720 p
= &mm
->mm_rb
.rb_node
;
723 pvma
= rb_entry(parent
, struct vm_area_struct
, vm_rb
);
725 /* sort by: start addr, end addr, VMA struct addr in that order
726 * (the latter is necessary as we may get identical VMAs) */
727 if (vma
->vm_start
< pvma
->vm_start
)
729 else if (vma
->vm_start
> pvma
->vm_start
) {
732 } else if (vma
->vm_end
< pvma
->vm_end
)
734 else if (vma
->vm_end
> pvma
->vm_end
) {
737 } else if (vma
< pvma
)
739 else if (vma
> pvma
) {
746 rb_link_node(&vma
->vm_rb
, parent
, p
);
747 rb_insert_color(&vma
->vm_rb
, &mm
->mm_rb
);
749 /* add VMA to the VMA list also */
752 prev
= rb_entry(rb_prev
, struct vm_area_struct
, vm_rb
);
754 __vma_link_list(mm
, vma
, prev
, parent
);
758 * delete a VMA from its owning mm_struct and address space
760 static void delete_vma_from_mm(struct vm_area_struct
*vma
)
763 struct address_space
*mapping
;
764 struct mm_struct
*mm
= vma
->vm_mm
;
765 struct task_struct
*curr
= current
;
770 for (i
= 0; i
< VMACACHE_SIZE
; i
++) {
771 /* if the vma is cached, invalidate the entire cache */
772 if (curr
->vmacache
[i
] == vma
) {
773 vmacache_invalidate(mm
);
778 /* remove the VMA from the mapping */
780 mapping
= vma
->vm_file
->f_mapping
;
782 i_mmap_lock_write(mapping
);
783 flush_dcache_mmap_lock(mapping
);
784 vma_interval_tree_remove(vma
, &mapping
->i_mmap
);
785 flush_dcache_mmap_unlock(mapping
);
786 i_mmap_unlock_write(mapping
);
789 /* remove from the MM's tree and list */
790 rb_erase(&vma
->vm_rb
, &mm
->mm_rb
);
793 vma
->vm_prev
->vm_next
= vma
->vm_next
;
795 mm
->mmap
= vma
->vm_next
;
798 vma
->vm_next
->vm_prev
= vma
->vm_prev
;
802 * destroy a VMA record
804 static void delete_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
806 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
807 vma
->vm_ops
->close(vma
);
810 put_nommu_region(vma
->vm_region
);
811 kmem_cache_free(vm_area_cachep
, vma
);
815 * look up the first VMA in which addr resides, NULL if none
816 * - should be called with mm->mmap_sem at least held readlocked
818 struct vm_area_struct
*find_vma(struct mm_struct
*mm
, unsigned long addr
)
820 struct vm_area_struct
*vma
;
822 /* check the cache first */
823 vma
= vmacache_find(mm
, addr
);
827 /* trawl the list (there may be multiple mappings in which addr
829 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
830 if (vma
->vm_start
> addr
)
832 if (vma
->vm_end
> addr
) {
833 vmacache_update(addr
, vma
);
840 EXPORT_SYMBOL(find_vma
);
844 * - we don't extend stack VMAs under NOMMU conditions
846 struct vm_area_struct
*find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
848 return find_vma(mm
, addr
);
852 * expand a stack to a given address
853 * - not supported under NOMMU conditions
855 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
861 * look up the first VMA exactly that exactly matches addr
862 * - should be called with mm->mmap_sem at least held readlocked
864 static struct vm_area_struct
*find_vma_exact(struct mm_struct
*mm
,
868 struct vm_area_struct
*vma
;
869 unsigned long end
= addr
+ len
;
871 /* check the cache first */
872 vma
= vmacache_find_exact(mm
, addr
, end
);
876 /* trawl the list (there may be multiple mappings in which addr
878 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
879 if (vma
->vm_start
< addr
)
881 if (vma
->vm_start
> addr
)
883 if (vma
->vm_end
== end
) {
884 vmacache_update(addr
, vma
);
893 * determine whether a mapping should be permitted and, if so, what sort of
894 * mapping we're capable of supporting
896 static int validate_mmap_request(struct file
*file
,
902 unsigned long *_capabilities
)
904 unsigned long capabilities
, rlen
;
907 /* do the simple checks first */
908 if (flags
& MAP_FIXED
)
911 if ((flags
& MAP_TYPE
) != MAP_PRIVATE
&&
912 (flags
& MAP_TYPE
) != MAP_SHARED
)
918 /* Careful about overflows.. */
919 rlen
= PAGE_ALIGN(len
);
920 if (!rlen
|| rlen
> TASK_SIZE
)
923 /* offset overflow? */
924 if ((pgoff
+ (rlen
>> PAGE_SHIFT
)) < pgoff
)
928 /* files must support mmap */
929 if (!file
->f_op
->mmap
)
932 /* work out if what we've got could possibly be shared
933 * - we support chardevs that provide their own "memory"
934 * - we support files/blockdevs that are memory backed
936 if (file
->f_op
->mmap_capabilities
) {
937 capabilities
= file
->f_op
->mmap_capabilities(file
);
939 /* no explicit capabilities set, so assume some
941 switch (file_inode(file
)->i_mode
& S_IFMT
) {
944 capabilities
= NOMMU_MAP_COPY
;
959 /* eliminate any capabilities that we can't support on this
961 if (!file
->f_op
->get_unmapped_area
)
962 capabilities
&= ~NOMMU_MAP_DIRECT
;
963 if (!(file
->f_mode
& FMODE_CAN_READ
))
964 capabilities
&= ~NOMMU_MAP_COPY
;
966 /* The file shall have been opened with read permission. */
967 if (!(file
->f_mode
& FMODE_READ
))
970 if (flags
& MAP_SHARED
) {
971 /* do checks for writing, appending and locking */
972 if ((prot
& PROT_WRITE
) &&
973 !(file
->f_mode
& FMODE_WRITE
))
976 if (IS_APPEND(file_inode(file
)) &&
977 (file
->f_mode
& FMODE_WRITE
))
980 if (locks_verify_locked(file
))
983 if (!(capabilities
& NOMMU_MAP_DIRECT
))
986 /* we mustn't privatise shared mappings */
987 capabilities
&= ~NOMMU_MAP_COPY
;
989 /* we're going to read the file into private memory we
991 if (!(capabilities
& NOMMU_MAP_COPY
))
994 /* we don't permit a private writable mapping to be
995 * shared with the backing device */
996 if (prot
& PROT_WRITE
)
997 capabilities
&= ~NOMMU_MAP_DIRECT
;
1000 if (capabilities
& NOMMU_MAP_DIRECT
) {
1001 if (((prot
& PROT_READ
) && !(capabilities
& NOMMU_MAP_READ
)) ||
1002 ((prot
& PROT_WRITE
) && !(capabilities
& NOMMU_MAP_WRITE
)) ||
1003 ((prot
& PROT_EXEC
) && !(capabilities
& NOMMU_MAP_EXEC
))
1005 capabilities
&= ~NOMMU_MAP_DIRECT
;
1006 if (flags
& MAP_SHARED
) {
1007 pr_warn("MAP_SHARED not completely supported on !MMU\n");
1013 /* handle executable mappings and implied executable
1015 if (path_noexec(&file
->f_path
)) {
1016 if (prot
& PROT_EXEC
)
1018 } else if ((prot
& PROT_READ
) && !(prot
& PROT_EXEC
)) {
1019 /* handle implication of PROT_EXEC by PROT_READ */
1020 if (current
->personality
& READ_IMPLIES_EXEC
) {
1021 if (capabilities
& NOMMU_MAP_EXEC
)
1024 } else if ((prot
& PROT_READ
) &&
1025 (prot
& PROT_EXEC
) &&
1026 !(capabilities
& NOMMU_MAP_EXEC
)
1028 /* backing file is not executable, try to copy */
1029 capabilities
&= ~NOMMU_MAP_DIRECT
;
1032 /* anonymous mappings are always memory backed and can be
1035 capabilities
= NOMMU_MAP_COPY
;
1037 /* handle PROT_EXEC implication by PROT_READ */
1038 if ((prot
& PROT_READ
) &&
1039 (current
->personality
& READ_IMPLIES_EXEC
))
1043 /* allow the security API to have its say */
1044 ret
= security_mmap_addr(addr
);
1049 *_capabilities
= capabilities
;
1054 * we've determined that we can make the mapping, now translate what we
1055 * now know into VMA flags
1057 static unsigned long determine_vm_flags(struct file
*file
,
1059 unsigned long flags
,
1060 unsigned long capabilities
)
1062 unsigned long vm_flags
;
1064 vm_flags
= calc_vm_prot_bits(prot
) | calc_vm_flag_bits(flags
);
1065 /* vm_flags |= mm->def_flags; */
1067 if (!(capabilities
& NOMMU_MAP_DIRECT
)) {
1068 /* attempt to share read-only copies of mapped file chunks */
1069 vm_flags
|= VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
;
1070 if (file
&& !(prot
& PROT_WRITE
))
1071 vm_flags
|= VM_MAYSHARE
;
1073 /* overlay a shareable mapping on the backing device or inode
1074 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1076 vm_flags
|= VM_MAYSHARE
| (capabilities
& NOMMU_VMFLAGS
);
1077 if (flags
& MAP_SHARED
)
1078 vm_flags
|= VM_SHARED
;
1081 /* refuse to let anyone share private mappings with this process if
1082 * it's being traced - otherwise breakpoints set in it may interfere
1083 * with another untraced process
1085 if ((flags
& MAP_PRIVATE
) && current
->ptrace
)
1086 vm_flags
&= ~VM_MAYSHARE
;
1092 * set up a shared mapping on a file (the driver or filesystem provides and
1095 static int do_mmap_shared_file(struct vm_area_struct
*vma
)
1099 ret
= vma
->vm_file
->f_op
->mmap(vma
->vm_file
, vma
);
1101 vma
->vm_region
->vm_top
= vma
->vm_region
->vm_end
;
1107 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1108 * opposed to tried but failed) so we can only give a suitable error as
1109 * it's not possible to make a private copy if MAP_SHARED was given */
1114 * set up a private mapping or an anonymous shared mapping
1116 static int do_mmap_private(struct vm_area_struct
*vma
,
1117 struct vm_region
*region
,
1119 unsigned long capabilities
)
1121 unsigned long total
, point
;
1125 /* invoke the file's mapping function so that it can keep track of
1126 * shared mappings on devices or memory
1127 * - VM_MAYSHARE will be set if it may attempt to share
1129 if (capabilities
& NOMMU_MAP_DIRECT
) {
1130 ret
= vma
->vm_file
->f_op
->mmap(vma
->vm_file
, vma
);
1132 /* shouldn't return success if we're not sharing */
1133 BUG_ON(!(vma
->vm_flags
& VM_MAYSHARE
));
1134 vma
->vm_region
->vm_top
= vma
->vm_region
->vm_end
;
1140 /* getting an ENOSYS error indicates that direct mmap isn't
1141 * possible (as opposed to tried but failed) so we'll try to
1142 * make a private copy of the data and map that instead */
1146 /* allocate some memory to hold the mapping
1147 * - note that this may not return a page-aligned address if the object
1148 * we're allocating is smaller than a page
1150 order
= get_order(len
);
1152 point
= len
>> PAGE_SHIFT
;
1154 /* we don't want to allocate a power-of-2 sized page set */
1155 if (sysctl_nr_trim_pages
&& total
- point
>= sysctl_nr_trim_pages
)
1158 base
= alloc_pages_exact(total
<< PAGE_SHIFT
, GFP_KERNEL
);
1162 atomic_long_add(total
, &mmap_pages_allocated
);
1164 region
->vm_flags
= vma
->vm_flags
|= VM_MAPPED_COPY
;
1165 region
->vm_start
= (unsigned long) base
;
1166 region
->vm_end
= region
->vm_start
+ len
;
1167 region
->vm_top
= region
->vm_start
+ (total
<< PAGE_SHIFT
);
1169 vma
->vm_start
= region
->vm_start
;
1170 vma
->vm_end
= region
->vm_start
+ len
;
1173 /* read the contents of a file into the copy */
1174 mm_segment_t old_fs
;
1177 fpos
= vma
->vm_pgoff
;
1178 fpos
<<= PAGE_SHIFT
;
1182 ret
= __vfs_read(vma
->vm_file
, base
, len
, &fpos
);
1188 /* clear the last little bit */
1190 memset(base
+ ret
, 0, len
- ret
);
1197 free_page_series(region
->vm_start
, region
->vm_top
);
1198 region
->vm_start
= vma
->vm_start
= 0;
1199 region
->vm_end
= vma
->vm_end
= 0;
1204 pr_err("Allocation of length %lu from process %d (%s) failed\n",
1205 len
, current
->pid
, current
->comm
);
1211 * handle mapping creation for uClinux
1213 unsigned long do_mmap(struct file
*file
,
1217 unsigned long flags
,
1218 vm_flags_t vm_flags
,
1219 unsigned long pgoff
,
1220 unsigned long *populate
)
1222 struct vm_area_struct
*vma
;
1223 struct vm_region
*region
;
1225 unsigned long capabilities
, result
;
1230 /* decide whether we should attempt the mapping, and if so what sort of
1232 ret
= validate_mmap_request(file
, addr
, len
, prot
, flags
, pgoff
,
1237 /* we ignore the address hint */
1239 len
= PAGE_ALIGN(len
);
1241 /* we've determined that we can make the mapping, now translate what we
1242 * now know into VMA flags */
1243 vm_flags
|= determine_vm_flags(file
, prot
, flags
, capabilities
);
1245 /* we're going to need to record the mapping */
1246 region
= kmem_cache_zalloc(vm_region_jar
, GFP_KERNEL
);
1248 goto error_getting_region
;
1250 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
1252 goto error_getting_vma
;
1254 region
->vm_usage
= 1;
1255 region
->vm_flags
= vm_flags
;
1256 region
->vm_pgoff
= pgoff
;
1258 INIT_LIST_HEAD(&vma
->anon_vma_chain
);
1259 vma
->vm_flags
= vm_flags
;
1260 vma
->vm_pgoff
= pgoff
;
1263 region
->vm_file
= get_file(file
);
1264 vma
->vm_file
= get_file(file
);
1267 down_write(&nommu_region_sem
);
1269 /* if we want to share, we need to check for regions created by other
1270 * mmap() calls that overlap with our proposed mapping
1271 * - we can only share with a superset match on most regular files
1272 * - shared mappings on character devices and memory backed files are
1273 * permitted to overlap inexactly as far as we are concerned for in
1274 * these cases, sharing is handled in the driver or filesystem rather
1277 if (vm_flags
& VM_MAYSHARE
) {
1278 struct vm_region
*pregion
;
1279 unsigned long pglen
, rpglen
, pgend
, rpgend
, start
;
1281 pglen
= (len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1282 pgend
= pgoff
+ pglen
;
1284 for (rb
= rb_first(&nommu_region_tree
); rb
; rb
= rb_next(rb
)) {
1285 pregion
= rb_entry(rb
, struct vm_region
, vm_rb
);
1287 if (!(pregion
->vm_flags
& VM_MAYSHARE
))
1290 /* search for overlapping mappings on the same file */
1291 if (file_inode(pregion
->vm_file
) !=
1295 if (pregion
->vm_pgoff
>= pgend
)
1298 rpglen
= pregion
->vm_end
- pregion
->vm_start
;
1299 rpglen
= (rpglen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1300 rpgend
= pregion
->vm_pgoff
+ rpglen
;
1301 if (pgoff
>= rpgend
)
1304 /* handle inexactly overlapping matches between
1306 if ((pregion
->vm_pgoff
!= pgoff
|| rpglen
!= pglen
) &&
1307 !(pgoff
>= pregion
->vm_pgoff
&& pgend
<= rpgend
)) {
1308 /* new mapping is not a subset of the region */
1309 if (!(capabilities
& NOMMU_MAP_DIRECT
))
1310 goto sharing_violation
;
1314 /* we've found a region we can share */
1315 pregion
->vm_usage
++;
1316 vma
->vm_region
= pregion
;
1317 start
= pregion
->vm_start
;
1318 start
+= (pgoff
- pregion
->vm_pgoff
) << PAGE_SHIFT
;
1319 vma
->vm_start
= start
;
1320 vma
->vm_end
= start
+ len
;
1322 if (pregion
->vm_flags
& VM_MAPPED_COPY
)
1323 vma
->vm_flags
|= VM_MAPPED_COPY
;
1325 ret
= do_mmap_shared_file(vma
);
1327 vma
->vm_region
= NULL
;
1330 pregion
->vm_usage
--;
1332 goto error_just_free
;
1335 fput(region
->vm_file
);
1336 kmem_cache_free(vm_region_jar
, region
);
1342 /* obtain the address at which to make a shared mapping
1343 * - this is the hook for quasi-memory character devices to
1344 * tell us the location of a shared mapping
1346 if (capabilities
& NOMMU_MAP_DIRECT
) {
1347 addr
= file
->f_op
->get_unmapped_area(file
, addr
, len
,
1349 if (IS_ERR_VALUE(addr
)) {
1352 goto error_just_free
;
1354 /* the driver refused to tell us where to site
1355 * the mapping so we'll have to attempt to copy
1358 if (!(capabilities
& NOMMU_MAP_COPY
))
1359 goto error_just_free
;
1361 capabilities
&= ~NOMMU_MAP_DIRECT
;
1363 vma
->vm_start
= region
->vm_start
= addr
;
1364 vma
->vm_end
= region
->vm_end
= addr
+ len
;
1369 vma
->vm_region
= region
;
1371 /* set up the mapping
1372 * - the region is filled in if NOMMU_MAP_DIRECT is still set
1374 if (file
&& vma
->vm_flags
& VM_SHARED
)
1375 ret
= do_mmap_shared_file(vma
);
1377 ret
= do_mmap_private(vma
, region
, len
, capabilities
);
1379 goto error_just_free
;
1380 add_nommu_region(region
);
1382 /* clear anonymous mappings that don't ask for uninitialized data */
1383 if (!vma
->vm_file
&& !(flags
& MAP_UNINITIALIZED
))
1384 memset((void *)region
->vm_start
, 0,
1385 region
->vm_end
- region
->vm_start
);
1387 /* okay... we have a mapping; now we have to register it */
1388 result
= vma
->vm_start
;
1390 current
->mm
->total_vm
+= len
>> PAGE_SHIFT
;
1393 add_vma_to_mm(current
->mm
, vma
);
1395 /* we flush the region from the icache only when the first executable
1396 * mapping of it is made */
1397 if (vma
->vm_flags
& VM_EXEC
&& !region
->vm_icache_flushed
) {
1398 flush_icache_range(region
->vm_start
, region
->vm_end
);
1399 region
->vm_icache_flushed
= true;
1402 up_write(&nommu_region_sem
);
1407 up_write(&nommu_region_sem
);
1409 if (region
->vm_file
)
1410 fput(region
->vm_file
);
1411 kmem_cache_free(vm_region_jar
, region
);
1414 kmem_cache_free(vm_area_cachep
, vma
);
1418 up_write(&nommu_region_sem
);
1419 pr_warn("Attempt to share mismatched mappings\n");
1424 kmem_cache_free(vm_region_jar
, region
);
1425 pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
1430 error_getting_region
:
1431 pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
1437 SYSCALL_DEFINE6(mmap_pgoff
, unsigned long, addr
, unsigned long, len
,
1438 unsigned long, prot
, unsigned long, flags
,
1439 unsigned long, fd
, unsigned long, pgoff
)
1441 struct file
*file
= NULL
;
1442 unsigned long retval
= -EBADF
;
1444 audit_mmap_fd(fd
, flags
);
1445 if (!(flags
& MAP_ANONYMOUS
)) {
1451 flags
&= ~(MAP_EXECUTABLE
| MAP_DENYWRITE
);
1453 retval
= vm_mmap_pgoff(file
, addr
, len
, prot
, flags
, pgoff
);
1461 #ifdef __ARCH_WANT_SYS_OLD_MMAP
1462 struct mmap_arg_struct
{
1466 unsigned long flags
;
1468 unsigned long offset
;
1471 SYSCALL_DEFINE1(old_mmap
, struct mmap_arg_struct __user
*, arg
)
1473 struct mmap_arg_struct a
;
1475 if (copy_from_user(&a
, arg
, sizeof(a
)))
1477 if (offset_in_page(a
.offset
))
1480 return sys_mmap_pgoff(a
.addr
, a
.len
, a
.prot
, a
.flags
, a
.fd
,
1481 a
.offset
>> PAGE_SHIFT
);
1483 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1486 * split a vma into two pieces at address 'addr', a new vma is allocated either
1487 * for the first part or the tail.
1489 int split_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1490 unsigned long addr
, int new_below
)
1492 struct vm_area_struct
*new;
1493 struct vm_region
*region
;
1494 unsigned long npages
;
1496 /* we're only permitted to split anonymous regions (these should have
1497 * only a single usage on the region) */
1501 if (mm
->map_count
>= sysctl_max_map_count
)
1504 region
= kmem_cache_alloc(vm_region_jar
, GFP_KERNEL
);
1508 new = kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
1510 kmem_cache_free(vm_region_jar
, region
);
1514 /* most fields are the same, copy all, and then fixup */
1516 *region
= *vma
->vm_region
;
1517 new->vm_region
= region
;
1519 npages
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
1522 region
->vm_top
= region
->vm_end
= new->vm_end
= addr
;
1524 region
->vm_start
= new->vm_start
= addr
;
1525 region
->vm_pgoff
= new->vm_pgoff
+= npages
;
1528 if (new->vm_ops
&& new->vm_ops
->open
)
1529 new->vm_ops
->open(new);
1531 delete_vma_from_mm(vma
);
1532 down_write(&nommu_region_sem
);
1533 delete_nommu_region(vma
->vm_region
);
1535 vma
->vm_region
->vm_start
= vma
->vm_start
= addr
;
1536 vma
->vm_region
->vm_pgoff
= vma
->vm_pgoff
+= npages
;
1538 vma
->vm_region
->vm_end
= vma
->vm_end
= addr
;
1539 vma
->vm_region
->vm_top
= addr
;
1541 add_nommu_region(vma
->vm_region
);
1542 add_nommu_region(new->vm_region
);
1543 up_write(&nommu_region_sem
);
1544 add_vma_to_mm(mm
, vma
);
1545 add_vma_to_mm(mm
, new);
1550 * shrink a VMA by removing the specified chunk from either the beginning or
1553 static int shrink_vma(struct mm_struct
*mm
,
1554 struct vm_area_struct
*vma
,
1555 unsigned long from
, unsigned long to
)
1557 struct vm_region
*region
;
1559 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1561 delete_vma_from_mm(vma
);
1562 if (from
> vma
->vm_start
)
1566 add_vma_to_mm(mm
, vma
);
1568 /* cut the backing region down to size */
1569 region
= vma
->vm_region
;
1570 BUG_ON(region
->vm_usage
!= 1);
1572 down_write(&nommu_region_sem
);
1573 delete_nommu_region(region
);
1574 if (from
> region
->vm_start
) {
1575 to
= region
->vm_top
;
1576 region
->vm_top
= region
->vm_end
= from
;
1578 region
->vm_start
= to
;
1580 add_nommu_region(region
);
1581 up_write(&nommu_region_sem
);
1583 free_page_series(from
, to
);
1589 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1590 * VMA, though it need not cover the whole VMA
1592 int do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
)
1594 struct vm_area_struct
*vma
;
1598 len
= PAGE_ALIGN(len
);
1604 /* find the first potentially overlapping VMA */
1605 vma
= find_vma(mm
, start
);
1609 pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
1610 current
->pid
, current
->comm
,
1611 start
, start
+ len
- 1);
1617 /* we're allowed to split an anonymous VMA but not a file-backed one */
1620 if (start
> vma
->vm_start
)
1622 if (end
== vma
->vm_end
)
1623 goto erase_whole_vma
;
1628 /* the chunk must be a subset of the VMA found */
1629 if (start
== vma
->vm_start
&& end
== vma
->vm_end
)
1630 goto erase_whole_vma
;
1631 if (start
< vma
->vm_start
|| end
> vma
->vm_end
)
1633 if (offset_in_page(start
))
1635 if (end
!= vma
->vm_end
&& offset_in_page(end
))
1637 if (start
!= vma
->vm_start
&& end
!= vma
->vm_end
) {
1638 ret
= split_vma(mm
, vma
, start
, 1);
1642 return shrink_vma(mm
, vma
, start
, end
);
1646 delete_vma_from_mm(vma
);
1647 delete_vma(mm
, vma
);
1650 EXPORT_SYMBOL(do_munmap
);
1652 int vm_munmap(unsigned long addr
, size_t len
)
1654 struct mm_struct
*mm
= current
->mm
;
1657 down_write(&mm
->mmap_sem
);
1658 ret
= do_munmap(mm
, addr
, len
);
1659 up_write(&mm
->mmap_sem
);
1662 EXPORT_SYMBOL(vm_munmap
);
1664 SYSCALL_DEFINE2(munmap
, unsigned long, addr
, size_t, len
)
1666 return vm_munmap(addr
, len
);
1670 * release all the mappings made in a process's VM space
1672 void exit_mmap(struct mm_struct
*mm
)
1674 struct vm_area_struct
*vma
;
1681 while ((vma
= mm
->mmap
)) {
1682 mm
->mmap
= vma
->vm_next
;
1683 delete_vma_from_mm(vma
);
1684 delete_vma(mm
, vma
);
1689 unsigned long vm_brk(unsigned long addr
, unsigned long len
)
1695 * expand (or shrink) an existing mapping, potentially moving it at the same
1696 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1698 * under NOMMU conditions, we only permit changing a mapping's size, and only
1699 * as long as it stays within the region allocated by do_mmap_private() and the
1700 * block is not shareable
1702 * MREMAP_FIXED is not supported under NOMMU conditions
1704 static unsigned long do_mremap(unsigned long addr
,
1705 unsigned long old_len
, unsigned long new_len
,
1706 unsigned long flags
, unsigned long new_addr
)
1708 struct vm_area_struct
*vma
;
1710 /* insanity checks first */
1711 old_len
= PAGE_ALIGN(old_len
);
1712 new_len
= PAGE_ALIGN(new_len
);
1713 if (old_len
== 0 || new_len
== 0)
1714 return (unsigned long) -EINVAL
;
1716 if (offset_in_page(addr
))
1719 if (flags
& MREMAP_FIXED
&& new_addr
!= addr
)
1720 return (unsigned long) -EINVAL
;
1722 vma
= find_vma_exact(current
->mm
, addr
, old_len
);
1724 return (unsigned long) -EINVAL
;
1726 if (vma
->vm_end
!= vma
->vm_start
+ old_len
)
1727 return (unsigned long) -EFAULT
;
1729 if (vma
->vm_flags
& VM_MAYSHARE
)
1730 return (unsigned long) -EPERM
;
1732 if (new_len
> vma
->vm_region
->vm_end
- vma
->vm_region
->vm_start
)
1733 return (unsigned long) -ENOMEM
;
1735 /* all checks complete - do it */
1736 vma
->vm_end
= vma
->vm_start
+ new_len
;
1737 return vma
->vm_start
;
1740 SYSCALL_DEFINE5(mremap
, unsigned long, addr
, unsigned long, old_len
,
1741 unsigned long, new_len
, unsigned long, flags
,
1742 unsigned long, new_addr
)
1746 down_write(¤t
->mm
->mmap_sem
);
1747 ret
= do_mremap(addr
, old_len
, new_len
, flags
, new_addr
);
1748 up_write(¤t
->mm
->mmap_sem
);
1752 struct page
*follow_page_mask(struct vm_area_struct
*vma
,
1753 unsigned long address
, unsigned int flags
,
1754 unsigned int *page_mask
)
1760 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long addr
,
1761 unsigned long pfn
, unsigned long size
, pgprot_t prot
)
1763 if (addr
!= (pfn
<< PAGE_SHIFT
))
1766 vma
->vm_flags
|= VM_IO
| VM_PFNMAP
| VM_DONTEXPAND
| VM_DONTDUMP
;
1769 EXPORT_SYMBOL(remap_pfn_range
);
1771 int vm_iomap_memory(struct vm_area_struct
*vma
, phys_addr_t start
, unsigned long len
)
1773 unsigned long pfn
= start
>> PAGE_SHIFT
;
1774 unsigned long vm_len
= vma
->vm_end
- vma
->vm_start
;
1776 pfn
+= vma
->vm_pgoff
;
1777 return io_remap_pfn_range(vma
, vma
->vm_start
, pfn
, vm_len
, vma
->vm_page_prot
);
1779 EXPORT_SYMBOL(vm_iomap_memory
);
1781 int remap_vmalloc_range(struct vm_area_struct
*vma
, void *addr
,
1782 unsigned long pgoff
)
1784 unsigned int size
= vma
->vm_end
- vma
->vm_start
;
1786 if (!(vma
->vm_flags
& VM_USERMAP
))
1789 vma
->vm_start
= (unsigned long)(addr
+ (pgoff
<< PAGE_SHIFT
));
1790 vma
->vm_end
= vma
->vm_start
+ size
;
1794 EXPORT_SYMBOL(remap_vmalloc_range
);
1796 unsigned long arch_get_unmapped_area(struct file
*file
, unsigned long addr
,
1797 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
1802 void unmap_mapping_range(struct address_space
*mapping
,
1803 loff_t
const holebegin
, loff_t
const holelen
,
1807 EXPORT_SYMBOL(unmap_mapping_range
);
1809 int filemap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1814 EXPORT_SYMBOL(filemap_fault
);
1816 void filemap_map_pages(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1820 EXPORT_SYMBOL(filemap_map_pages
);
1822 static int __access_remote_vm(struct task_struct
*tsk
, struct mm_struct
*mm
,
1823 unsigned long addr
, void *buf
, int len
, int write
)
1825 struct vm_area_struct
*vma
;
1827 down_read(&mm
->mmap_sem
);
1829 /* the access must start within one of the target process's mappings */
1830 vma
= find_vma(mm
, addr
);
1832 /* don't overrun this mapping */
1833 if (addr
+ len
>= vma
->vm_end
)
1834 len
= vma
->vm_end
- addr
;
1836 /* only read or write mappings where it is permitted */
1837 if (write
&& vma
->vm_flags
& VM_MAYWRITE
)
1838 copy_to_user_page(vma
, NULL
, addr
,
1839 (void *) addr
, buf
, len
);
1840 else if (!write
&& vma
->vm_flags
& VM_MAYREAD
)
1841 copy_from_user_page(vma
, NULL
, addr
,
1842 buf
, (void *) addr
, len
);
1849 up_read(&mm
->mmap_sem
);
1855 * @access_remote_vm - access another process' address space
1856 * @mm: the mm_struct of the target address space
1857 * @addr: start address to access
1858 * @buf: source or destination buffer
1859 * @len: number of bytes to transfer
1860 * @write: whether the access is a write
1862 * The caller must hold a reference on @mm.
1864 int access_remote_vm(struct mm_struct
*mm
, unsigned long addr
,
1865 void *buf
, int len
, int write
)
1867 return __access_remote_vm(NULL
, mm
, addr
, buf
, len
, write
);
1871 * Access another process' address space.
1872 * - source/target buffer must be kernel space
1874 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
1876 struct mm_struct
*mm
;
1878 if (addr
+ len
< addr
)
1881 mm
= get_task_mm(tsk
);
1885 len
= __access_remote_vm(tsk
, mm
, addr
, buf
, len
, write
);
1892 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
1893 * @inode: The inode to check
1894 * @size: The current filesize of the inode
1895 * @newsize: The proposed filesize of the inode
1897 * Check the shared mappings on an inode on behalf of a shrinking truncate to
1898 * make sure that that any outstanding VMAs aren't broken and then shrink the
1899 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
1900 * automatically grant mappings that are too large.
1902 int nommu_shrink_inode_mappings(struct inode
*inode
, size_t size
,
1905 struct vm_area_struct
*vma
;
1906 struct vm_region
*region
;
1908 size_t r_size
, r_top
;
1910 low
= newsize
>> PAGE_SHIFT
;
1911 high
= (size
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1913 down_write(&nommu_region_sem
);
1914 i_mmap_lock_read(inode
->i_mapping
);
1916 /* search for VMAs that fall within the dead zone */
1917 vma_interval_tree_foreach(vma
, &inode
->i_mapping
->i_mmap
, low
, high
) {
1918 /* found one - only interested if it's shared out of the page
1920 if (vma
->vm_flags
& VM_SHARED
) {
1921 i_mmap_unlock_read(inode
->i_mapping
);
1922 up_write(&nommu_region_sem
);
1923 return -ETXTBSY
; /* not quite true, but near enough */
1927 /* reduce any regions that overlap the dead zone - if in existence,
1928 * these will be pointed to by VMAs that don't overlap the dead zone
1930 * we don't check for any regions that start beyond the EOF as there
1933 vma_interval_tree_foreach(vma
, &inode
->i_mapping
->i_mmap
, 0, ULONG_MAX
) {
1934 if (!(vma
->vm_flags
& VM_SHARED
))
1937 region
= vma
->vm_region
;
1938 r_size
= region
->vm_top
- region
->vm_start
;
1939 r_top
= (region
->vm_pgoff
<< PAGE_SHIFT
) + r_size
;
1941 if (r_top
> newsize
) {
1942 region
->vm_top
-= r_top
- newsize
;
1943 if (region
->vm_end
> region
->vm_top
)
1944 region
->vm_end
= region
->vm_top
;
1948 i_mmap_unlock_read(inode
->i_mapping
);
1949 up_write(&nommu_region_sem
);
1954 * Initialise sysctl_user_reserve_kbytes.
1956 * This is intended to prevent a user from starting a single memory hogging
1957 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
1960 * The default value is min(3% of free memory, 128MB)
1961 * 128MB is enough to recover with sshd/login, bash, and top/kill.
1963 static int __meminit
init_user_reserve(void)
1965 unsigned long free_kbytes
;
1967 free_kbytes
= global_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
1969 sysctl_user_reserve_kbytes
= min(free_kbytes
/ 32, 1UL << 17);
1972 subsys_initcall(init_user_reserve
);
1975 * Initialise sysctl_admin_reserve_kbytes.
1977 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
1978 * to log in and kill a memory hogging process.
1980 * Systems with more than 256MB will reserve 8MB, enough to recover
1981 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
1982 * only reserve 3% of free pages by default.
1984 static int __meminit
init_admin_reserve(void)
1986 unsigned long free_kbytes
;
1988 free_kbytes
= global_page_state(NR_FREE_PAGES
) << (PAGE_SHIFT
- 10);
1990 sysctl_admin_reserve_kbytes
= min(free_kbytes
/ 32, 1UL << 13);
1993 subsys_initcall(init_admin_reserve
);