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) 2007-2009 Paul Mundt <lethal@linux-sh.org>
16 #include <linux/module.h>
18 #include <linux/mman.h>
19 #include <linux/swap.h>
20 #include <linux/file.h>
21 #include <linux/highmem.h>
22 #include <linux/pagemap.h>
23 #include <linux/slab.h>
24 #include <linux/vmalloc.h>
25 #include <linux/tracehook.h>
26 #include <linux/blkdev.h>
27 #include <linux/backing-dev.h>
28 #include <linux/mount.h>
29 #include <linux/personality.h>
30 #include <linux/security.h>
31 #include <linux/syscalls.h>
33 #include <asm/uaccess.h>
35 #include <asm/tlbflush.h>
38 static inline __attribute__((format(printf
, 1, 2)))
39 void no_printk(const char *fmt
, ...)
44 #define kenter(FMT, ...) \
45 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
46 #define kleave(FMT, ...) \
47 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
48 #define kdebug(FMT, ...) \
49 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
51 #define kenter(FMT, ...) \
52 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
53 #define kleave(FMT, ...) \
54 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
55 #define kdebug(FMT, ...) \
56 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
61 unsigned long max_mapnr
;
62 unsigned long num_physpages
;
63 struct percpu_counter vm_committed_as
;
64 int sysctl_overcommit_memory
= OVERCOMMIT_GUESS
; /* heuristic overcommit */
65 int sysctl_overcommit_ratio
= 50; /* default is 50% */
66 int sysctl_max_map_count
= DEFAULT_MAX_MAP_COUNT
;
67 int sysctl_nr_trim_pages
= CONFIG_NOMMU_INITIAL_TRIM_EXCESS
;
68 int heap_stack_gap
= 0;
70 atomic_long_t mmap_pages_allocated
;
72 EXPORT_SYMBOL(mem_map
);
73 EXPORT_SYMBOL(num_physpages
);
75 /* list of mapped, potentially shareable regions */
76 static struct kmem_cache
*vm_region_jar
;
77 struct rb_root nommu_region_tree
= RB_ROOT
;
78 DECLARE_RWSEM(nommu_region_sem
);
80 struct vm_operations_struct generic_file_vm_ops
= {
84 * Handle all mappings that got truncated by a "truncate()"
87 * NOTE! We have to be ready to update the memory sharing
88 * between the file and the memory map for a potential last
89 * incomplete page. Ugly, but necessary.
91 int vmtruncate(struct inode
*inode
, loff_t offset
)
93 struct address_space
*mapping
= inode
->i_mapping
;
96 if (inode
->i_size
< offset
)
98 i_size_write(inode
, offset
);
100 truncate_inode_pages(mapping
, offset
);
104 limit
= current
->signal
->rlim
[RLIMIT_FSIZE
].rlim_cur
;
105 if (limit
!= RLIM_INFINITY
&& offset
> limit
)
107 if (offset
> inode
->i_sb
->s_maxbytes
)
109 i_size_write(inode
, offset
);
112 if (inode
->i_op
->truncate
)
113 inode
->i_op
->truncate(inode
);
116 send_sig(SIGXFSZ
, current
, 0);
121 EXPORT_SYMBOL(vmtruncate
);
124 * Return the total memory allocated for this pointer, not
125 * just what the caller asked for.
127 * Doesn't have to be accurate, i.e. may have races.
129 unsigned int kobjsize(const void *objp
)
134 * If the object we have should not have ksize performed on it,
137 if (!objp
|| !virt_addr_valid(objp
))
140 page
= virt_to_head_page(objp
);
143 * If the allocator sets PageSlab, we know the pointer came from
150 * If it's not a compound page, see if we have a matching VMA
151 * region. This test is intentionally done in reverse order,
152 * so if there's no VMA, we still fall through and hand back
153 * PAGE_SIZE for 0-order pages.
155 if (!PageCompound(page
)) {
156 struct vm_area_struct
*vma
;
158 vma
= find_vma(current
->mm
, (unsigned long)objp
);
160 return vma
->vm_end
- vma
->vm_start
;
164 * The ksize() function is only guaranteed to work for pointers
165 * returned by kmalloc(). So handle arbitrary pointers here.
167 return PAGE_SIZE
<< compound_order(page
);
170 int __get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
171 unsigned long start
, int nr_pages
, int flags
,
172 struct page
**pages
, struct vm_area_struct
**vmas
)
174 struct vm_area_struct
*vma
;
175 unsigned long vm_flags
;
177 int write
= !!(flags
& GUP_FLAGS_WRITE
);
178 int force
= !!(flags
& GUP_FLAGS_FORCE
);
180 /* calculate required read or write permissions.
181 * - if 'force' is set, we only require the "MAY" flags.
183 vm_flags
= write
? (VM_WRITE
| VM_MAYWRITE
) : (VM_READ
| VM_MAYREAD
);
184 vm_flags
&= force
? (VM_MAYREAD
| VM_MAYWRITE
) : (VM_READ
| VM_WRITE
);
186 for (i
= 0; i
< nr_pages
; i
++) {
187 vma
= find_vma(mm
, start
);
189 goto finish_or_fault
;
191 /* protect what we can, including chardevs */
192 if ((vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)) ||
193 !(vm_flags
& vma
->vm_flags
))
194 goto finish_or_fault
;
197 pages
[i
] = virt_to_page(start
);
199 page_cache_get(pages
[i
]);
209 return i
? : -EFAULT
;
213 * get a list of pages in an address range belonging to the specified process
214 * and indicate the VMA that covers each page
215 * - this is potentially dodgy as we may end incrementing the page count of a
216 * slab page or a secondary page from a compound page
217 * - don't permit access to VMAs that don't support it, such as I/O mappings
219 int get_user_pages(struct task_struct
*tsk
, struct mm_struct
*mm
,
220 unsigned long start
, int nr_pages
, int write
, int force
,
221 struct page
**pages
, struct vm_area_struct
**vmas
)
226 flags
|= GUP_FLAGS_WRITE
;
228 flags
|= GUP_FLAGS_FORCE
;
230 return __get_user_pages(tsk
, mm
, start
, nr_pages
, flags
, pages
, vmas
);
232 EXPORT_SYMBOL(get_user_pages
);
235 * follow_pfn - look up PFN at a user virtual address
236 * @vma: memory mapping
237 * @address: user virtual address
238 * @pfn: location to store found PFN
240 * Only IO mappings and raw PFN mappings are allowed.
242 * Returns zero and the pfn at @pfn on success, -ve otherwise.
244 int follow_pfn(struct vm_area_struct
*vma
, unsigned long address
,
247 if (!(vma
->vm_flags
& (VM_IO
| VM_PFNMAP
)))
250 *pfn
= address
>> PAGE_SHIFT
;
253 EXPORT_SYMBOL(follow_pfn
);
255 DEFINE_RWLOCK(vmlist_lock
);
256 struct vm_struct
*vmlist
;
258 void vfree(const void *addr
)
262 EXPORT_SYMBOL(vfree
);
264 void *__vmalloc(unsigned long size
, gfp_t gfp_mask
, pgprot_t prot
)
267 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
268 * returns only a logical address.
270 return kmalloc(size
, (gfp_mask
| __GFP_COMP
) & ~__GFP_HIGHMEM
);
272 EXPORT_SYMBOL(__vmalloc
);
274 void *vmalloc_user(unsigned long size
)
278 ret
= __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
| __GFP_ZERO
,
281 struct vm_area_struct
*vma
;
283 down_write(¤t
->mm
->mmap_sem
);
284 vma
= find_vma(current
->mm
, (unsigned long)ret
);
286 vma
->vm_flags
|= VM_USERMAP
;
287 up_write(¤t
->mm
->mmap_sem
);
292 EXPORT_SYMBOL(vmalloc_user
);
294 struct page
*vmalloc_to_page(const void *addr
)
296 return virt_to_page(addr
);
298 EXPORT_SYMBOL(vmalloc_to_page
);
300 unsigned long vmalloc_to_pfn(const void *addr
)
302 return page_to_pfn(virt_to_page(addr
));
304 EXPORT_SYMBOL(vmalloc_to_pfn
);
306 long vread(char *buf
, char *addr
, unsigned long count
)
308 memcpy(buf
, addr
, count
);
312 long vwrite(char *buf
, char *addr
, unsigned long count
)
314 /* Don't allow overflow */
315 if ((unsigned long) addr
+ count
< count
)
316 count
= -(unsigned long) addr
;
318 memcpy(addr
, buf
, count
);
323 * vmalloc - allocate virtually continguos memory
325 * @size: allocation size
327 * Allocate enough pages to cover @size from the page level
328 * allocator and map them into continguos kernel virtual space.
330 * For tight control over page level allocator and protection flags
331 * use __vmalloc() instead.
333 void *vmalloc(unsigned long size
)
335 return __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
, PAGE_KERNEL
);
337 EXPORT_SYMBOL(vmalloc
);
339 void *vmalloc_node(unsigned long size
, int node
)
341 return vmalloc(size
);
343 EXPORT_SYMBOL(vmalloc_node
);
345 #ifndef PAGE_KERNEL_EXEC
346 # define PAGE_KERNEL_EXEC PAGE_KERNEL
350 * vmalloc_exec - allocate virtually contiguous, executable memory
351 * @size: allocation size
353 * Kernel-internal function to allocate enough pages to cover @size
354 * the page level allocator and map them into contiguous and
355 * executable kernel virtual space.
357 * For tight control over page level allocator and protection flags
358 * use __vmalloc() instead.
361 void *vmalloc_exec(unsigned long size
)
363 return __vmalloc(size
, GFP_KERNEL
| __GFP_HIGHMEM
, PAGE_KERNEL_EXEC
);
367 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
368 * @size: allocation size
370 * Allocate enough 32bit PA addressable pages to cover @size from the
371 * page level allocator and map them into continguos kernel virtual space.
373 void *vmalloc_32(unsigned long size
)
375 return __vmalloc(size
, GFP_KERNEL
, PAGE_KERNEL
);
377 EXPORT_SYMBOL(vmalloc_32
);
380 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
381 * @size: allocation size
383 * The resulting memory area is 32bit addressable and zeroed so it can be
384 * mapped to userspace without leaking data.
386 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
387 * remap_vmalloc_range() are permissible.
389 void *vmalloc_32_user(unsigned long size
)
392 * We'll have to sort out the ZONE_DMA bits for 64-bit,
393 * but for now this can simply use vmalloc_user() directly.
395 return vmalloc_user(size
);
397 EXPORT_SYMBOL(vmalloc_32_user
);
399 void *vmap(struct page
**pages
, unsigned int count
, unsigned long flags
, pgprot_t prot
)
406 void vunmap(const void *addr
)
410 EXPORT_SYMBOL(vunmap
);
412 void *vm_map_ram(struct page
**pages
, unsigned int count
, int node
, pgprot_t prot
)
417 EXPORT_SYMBOL(vm_map_ram
);
419 void vm_unmap_ram(const void *mem
, unsigned int count
)
423 EXPORT_SYMBOL(vm_unmap_ram
);
425 void vm_unmap_aliases(void)
428 EXPORT_SYMBOL_GPL(vm_unmap_aliases
);
431 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
434 void __attribute__((weak
)) vmalloc_sync_all(void)
438 int vm_insert_page(struct vm_area_struct
*vma
, unsigned long addr
,
443 EXPORT_SYMBOL(vm_insert_page
);
446 * sys_brk() for the most part doesn't need the global kernel
447 * lock, except when an application is doing something nasty
448 * like trying to un-brk an area that has already been mapped
449 * to a regular file. in this case, the unmapping will need
450 * to invoke file system routines that need the global lock.
452 SYSCALL_DEFINE1(brk
, unsigned long, brk
)
454 struct mm_struct
*mm
= current
->mm
;
456 if (brk
< mm
->start_brk
|| brk
> mm
->context
.end_brk
)
463 * Always allow shrinking brk
465 if (brk
<= mm
->brk
) {
471 * Ok, looks good - let it rip.
473 return mm
->brk
= brk
;
477 * initialise the VMA and region record slabs
479 void __init
mmap_init(void)
483 ret
= percpu_counter_init(&vm_committed_as
, 0);
485 vm_region_jar
= KMEM_CACHE(vm_region
, SLAB_PANIC
);
489 * validate the region tree
490 * - the caller must hold the region lock
492 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
493 static noinline
void validate_nommu_regions(void)
495 struct vm_region
*region
, *last
;
496 struct rb_node
*p
, *lastp
;
498 lastp
= rb_first(&nommu_region_tree
);
502 last
= rb_entry(lastp
, struct vm_region
, vm_rb
);
503 BUG_ON(unlikely(last
->vm_end
<= last
->vm_start
));
504 BUG_ON(unlikely(last
->vm_top
< last
->vm_end
));
506 while ((p
= rb_next(lastp
))) {
507 region
= rb_entry(p
, struct vm_region
, vm_rb
);
508 last
= rb_entry(lastp
, struct vm_region
, vm_rb
);
510 BUG_ON(unlikely(region
->vm_end
<= region
->vm_start
));
511 BUG_ON(unlikely(region
->vm_top
< region
->vm_end
));
512 BUG_ON(unlikely(region
->vm_start
< last
->vm_top
));
518 static void validate_nommu_regions(void)
524 * add a region into the global tree
526 static void add_nommu_region(struct vm_region
*region
)
528 struct vm_region
*pregion
;
529 struct rb_node
**p
, *parent
;
531 validate_nommu_regions();
534 p
= &nommu_region_tree
.rb_node
;
537 pregion
= rb_entry(parent
, struct vm_region
, vm_rb
);
538 if (region
->vm_start
< pregion
->vm_start
)
540 else if (region
->vm_start
> pregion
->vm_start
)
542 else if (pregion
== region
)
548 rb_link_node(®ion
->vm_rb
, parent
, p
);
549 rb_insert_color(®ion
->vm_rb
, &nommu_region_tree
);
551 validate_nommu_regions();
555 * delete a region from the global tree
557 static void delete_nommu_region(struct vm_region
*region
)
559 BUG_ON(!nommu_region_tree
.rb_node
);
561 validate_nommu_regions();
562 rb_erase(®ion
->vm_rb
, &nommu_region_tree
);
563 validate_nommu_regions();
567 * free a contiguous series of pages
569 static void free_page_series(unsigned long from
, unsigned long to
)
571 for (; from
< to
; from
+= PAGE_SIZE
) {
572 struct page
*page
= virt_to_page(from
);
574 kdebug("- free %lx", from
);
575 atomic_long_dec(&mmap_pages_allocated
);
576 if (page_count(page
) != 1)
577 kdebug("free page %p: refcount not one: %d",
578 page
, page_count(page
));
584 * release a reference to a region
585 * - the caller must hold the region semaphore for writing, which this releases
586 * - the region may not have been added to the tree yet, in which case vm_top
587 * will equal vm_start
589 static void __put_nommu_region(struct vm_region
*region
)
590 __releases(nommu_region_sem
)
592 kenter("%p{%d}", region
, atomic_read(®ion
->vm_usage
));
594 BUG_ON(!nommu_region_tree
.rb_node
);
596 if (atomic_dec_and_test(®ion
->vm_usage
)) {
597 if (region
->vm_top
> region
->vm_start
)
598 delete_nommu_region(region
);
599 up_write(&nommu_region_sem
);
602 fput(region
->vm_file
);
604 /* IO memory and memory shared directly out of the pagecache
605 * from ramfs/tmpfs mustn't be released here */
606 if (region
->vm_flags
& VM_MAPPED_COPY
) {
607 kdebug("free series");
608 free_page_series(region
->vm_start
, region
->vm_top
);
610 kmem_cache_free(vm_region_jar
, region
);
612 up_write(&nommu_region_sem
);
617 * release a reference to a region
619 static void put_nommu_region(struct vm_region
*region
)
621 down_write(&nommu_region_sem
);
622 __put_nommu_region(region
);
626 * add a VMA into a process's mm_struct in the appropriate place in the list
627 * and tree and add to the address space's page tree also if not an anonymous
629 * - should be called with mm->mmap_sem held writelocked
631 static void add_vma_to_mm(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
633 struct vm_area_struct
*pvma
, **pp
;
634 struct address_space
*mapping
;
635 struct rb_node
**p
, *parent
;
639 BUG_ON(!vma
->vm_region
);
644 /* add the VMA to the mapping */
646 mapping
= vma
->vm_file
->f_mapping
;
648 flush_dcache_mmap_lock(mapping
);
649 vma_prio_tree_insert(vma
, &mapping
->i_mmap
);
650 flush_dcache_mmap_unlock(mapping
);
653 /* add the VMA to the tree */
655 p
= &mm
->mm_rb
.rb_node
;
658 pvma
= rb_entry(parent
, struct vm_area_struct
, vm_rb
);
660 /* sort by: start addr, end addr, VMA struct addr in that order
661 * (the latter is necessary as we may get identical VMAs) */
662 if (vma
->vm_start
< pvma
->vm_start
)
664 else if (vma
->vm_start
> pvma
->vm_start
)
666 else if (vma
->vm_end
< pvma
->vm_end
)
668 else if (vma
->vm_end
> pvma
->vm_end
)
678 rb_link_node(&vma
->vm_rb
, parent
, p
);
679 rb_insert_color(&vma
->vm_rb
, &mm
->mm_rb
);
681 /* add VMA to the VMA list also */
682 for (pp
= &mm
->mmap
; (pvma
= *pp
); pp
= &(*pp
)->vm_next
) {
683 if (pvma
->vm_start
> vma
->vm_start
)
685 if (pvma
->vm_start
< vma
->vm_start
)
687 if (pvma
->vm_end
< vma
->vm_end
)
696 * delete a VMA from its owning mm_struct and address space
698 static void delete_vma_from_mm(struct vm_area_struct
*vma
)
700 struct vm_area_struct
**pp
;
701 struct address_space
*mapping
;
702 struct mm_struct
*mm
= vma
->vm_mm
;
707 if (mm
->mmap_cache
== vma
)
708 mm
->mmap_cache
= NULL
;
710 /* remove the VMA from the mapping */
712 mapping
= vma
->vm_file
->f_mapping
;
714 flush_dcache_mmap_lock(mapping
);
715 vma_prio_tree_remove(vma
, &mapping
->i_mmap
);
716 flush_dcache_mmap_unlock(mapping
);
719 /* remove from the MM's tree and list */
720 rb_erase(&vma
->vm_rb
, &mm
->mm_rb
);
721 for (pp
= &mm
->mmap
; *pp
; pp
= &(*pp
)->vm_next
) {
732 * destroy a VMA record
734 static void delete_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
)
737 if (vma
->vm_ops
&& vma
->vm_ops
->close
)
738 vma
->vm_ops
->close(vma
);
741 if (vma
->vm_flags
& VM_EXECUTABLE
)
742 removed_exe_file_vma(mm
);
744 put_nommu_region(vma
->vm_region
);
745 kmem_cache_free(vm_area_cachep
, vma
);
749 * look up the first VMA in which addr resides, NULL if none
750 * - should be called with mm->mmap_sem at least held readlocked
752 struct vm_area_struct
*find_vma(struct mm_struct
*mm
, unsigned long addr
)
754 struct vm_area_struct
*vma
;
755 struct rb_node
*n
= mm
->mm_rb
.rb_node
;
757 /* check the cache first */
758 vma
= mm
->mmap_cache
;
759 if (vma
&& vma
->vm_start
<= addr
&& vma
->vm_end
> addr
)
762 /* trawl the tree (there may be multiple mappings in which addr
764 for (n
= rb_first(&mm
->mm_rb
); n
; n
= rb_next(n
)) {
765 vma
= rb_entry(n
, struct vm_area_struct
, vm_rb
);
766 if (vma
->vm_start
> addr
)
768 if (vma
->vm_end
> addr
) {
769 mm
->mmap_cache
= vma
;
776 EXPORT_SYMBOL(find_vma
);
780 * - we don't extend stack VMAs under NOMMU conditions
782 struct vm_area_struct
*find_extend_vma(struct mm_struct
*mm
, unsigned long addr
)
784 return find_vma(mm
, addr
);
788 * expand a stack to a given address
789 * - not supported under NOMMU conditions
791 int expand_stack(struct vm_area_struct
*vma
, unsigned long address
)
797 * look up the first VMA exactly that exactly matches addr
798 * - should be called with mm->mmap_sem at least held readlocked
800 static struct vm_area_struct
*find_vma_exact(struct mm_struct
*mm
,
804 struct vm_area_struct
*vma
;
805 struct rb_node
*n
= mm
->mm_rb
.rb_node
;
806 unsigned long end
= addr
+ len
;
808 /* check the cache first */
809 vma
= mm
->mmap_cache
;
810 if (vma
&& vma
->vm_start
== addr
&& vma
->vm_end
== end
)
813 /* trawl the tree (there may be multiple mappings in which addr
815 for (n
= rb_first(&mm
->mm_rb
); n
; n
= rb_next(n
)) {
816 vma
= rb_entry(n
, struct vm_area_struct
, vm_rb
);
817 if (vma
->vm_start
< addr
)
819 if (vma
->vm_start
> addr
)
821 if (vma
->vm_end
== end
) {
822 mm
->mmap_cache
= vma
;
831 * determine whether a mapping should be permitted and, if so, what sort of
832 * mapping we're capable of supporting
834 static int validate_mmap_request(struct file
*file
,
840 unsigned long *_capabilities
)
842 unsigned long capabilities
, rlen
;
843 unsigned long reqprot
= prot
;
846 /* do the simple checks first */
847 if (flags
& MAP_FIXED
|| addr
) {
849 "%d: Can't do fixed-address/overlay mmap of RAM\n",
854 if ((flags
& MAP_TYPE
) != MAP_PRIVATE
&&
855 (flags
& MAP_TYPE
) != MAP_SHARED
)
861 /* Careful about overflows.. */
862 rlen
= PAGE_ALIGN(len
);
863 if (!rlen
|| rlen
> TASK_SIZE
)
866 /* offset overflow? */
867 if ((pgoff
+ (rlen
>> PAGE_SHIFT
)) < pgoff
)
871 /* validate file mapping requests */
872 struct address_space
*mapping
;
874 /* files must support mmap */
875 if (!file
->f_op
|| !file
->f_op
->mmap
)
878 /* work out if what we've got could possibly be shared
879 * - we support chardevs that provide their own "memory"
880 * - we support files/blockdevs that are memory backed
882 mapping
= file
->f_mapping
;
884 mapping
= file
->f_path
.dentry
->d_inode
->i_mapping
;
887 if (mapping
&& mapping
->backing_dev_info
)
888 capabilities
= mapping
->backing_dev_info
->capabilities
;
891 /* no explicit capabilities set, so assume some
893 switch (file
->f_path
.dentry
->d_inode
->i_mode
& S_IFMT
) {
896 capabilities
= BDI_CAP_MAP_COPY
;
911 /* eliminate any capabilities that we can't support on this
913 if (!file
->f_op
->get_unmapped_area
)
914 capabilities
&= ~BDI_CAP_MAP_DIRECT
;
915 if (!file
->f_op
->read
)
916 capabilities
&= ~BDI_CAP_MAP_COPY
;
918 /* The file shall have been opened with read permission. */
919 if (!(file
->f_mode
& FMODE_READ
))
922 if (flags
& MAP_SHARED
) {
923 /* do checks for writing, appending and locking */
924 if ((prot
& PROT_WRITE
) &&
925 !(file
->f_mode
& FMODE_WRITE
))
928 if (IS_APPEND(file
->f_path
.dentry
->d_inode
) &&
929 (file
->f_mode
& FMODE_WRITE
))
932 if (locks_verify_locked(file
->f_path
.dentry
->d_inode
))
935 if (!(capabilities
& BDI_CAP_MAP_DIRECT
))
938 if (((prot
& PROT_READ
) && !(capabilities
& BDI_CAP_READ_MAP
)) ||
939 ((prot
& PROT_WRITE
) && !(capabilities
& BDI_CAP_WRITE_MAP
)) ||
940 ((prot
& PROT_EXEC
) && !(capabilities
& BDI_CAP_EXEC_MAP
))
942 printk("MAP_SHARED not completely supported on !MMU\n");
946 /* we mustn't privatise shared mappings */
947 capabilities
&= ~BDI_CAP_MAP_COPY
;
950 /* we're going to read the file into private memory we
952 if (!(capabilities
& BDI_CAP_MAP_COPY
))
955 /* we don't permit a private writable mapping to be
956 * shared with the backing device */
957 if (prot
& PROT_WRITE
)
958 capabilities
&= ~BDI_CAP_MAP_DIRECT
;
961 /* handle executable mappings and implied executable
963 if (file
->f_path
.mnt
->mnt_flags
& MNT_NOEXEC
) {
964 if (prot
& PROT_EXEC
)
967 else if ((prot
& PROT_READ
) && !(prot
& PROT_EXEC
)) {
968 /* handle implication of PROT_EXEC by PROT_READ */
969 if (current
->personality
& READ_IMPLIES_EXEC
) {
970 if (capabilities
& BDI_CAP_EXEC_MAP
)
974 else if ((prot
& PROT_READ
) &&
975 (prot
& PROT_EXEC
) &&
976 !(capabilities
& BDI_CAP_EXEC_MAP
)
978 /* backing file is not executable, try to copy */
979 capabilities
&= ~BDI_CAP_MAP_DIRECT
;
983 /* anonymous mappings are always memory backed and can be
986 capabilities
= BDI_CAP_MAP_COPY
;
988 /* handle PROT_EXEC implication by PROT_READ */
989 if ((prot
& PROT_READ
) &&
990 (current
->personality
& READ_IMPLIES_EXEC
))
994 /* allow the security API to have its say */
995 ret
= security_file_mmap(file
, reqprot
, prot
, flags
, addr
, 0);
1000 *_capabilities
= capabilities
;
1005 * we've determined that we can make the mapping, now translate what we
1006 * now know into VMA flags
1008 static unsigned long determine_vm_flags(struct file
*file
,
1010 unsigned long flags
,
1011 unsigned long capabilities
)
1013 unsigned long vm_flags
;
1015 vm_flags
= calc_vm_prot_bits(prot
) | calc_vm_flag_bits(flags
);
1016 vm_flags
|= VM_MAYREAD
| VM_MAYWRITE
| VM_MAYEXEC
;
1017 /* vm_flags |= mm->def_flags; */
1019 if (!(capabilities
& BDI_CAP_MAP_DIRECT
)) {
1020 /* attempt to share read-only copies of mapped file chunks */
1021 if (file
&& !(prot
& PROT_WRITE
))
1022 vm_flags
|= VM_MAYSHARE
;
1025 /* overlay a shareable mapping on the backing device or inode
1026 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1028 if (flags
& MAP_SHARED
)
1029 vm_flags
|= VM_MAYSHARE
| VM_SHARED
;
1030 else if ((((vm_flags
& capabilities
) ^ vm_flags
) & BDI_CAP_VMFLAGS
) == 0)
1031 vm_flags
|= VM_MAYSHARE
;
1034 /* refuse to let anyone share private mappings with this process if
1035 * it's being traced - otherwise breakpoints set in it may interfere
1036 * with another untraced process
1038 if ((flags
& MAP_PRIVATE
) && tracehook_expect_breakpoints(current
))
1039 vm_flags
&= ~VM_MAYSHARE
;
1045 * set up a shared mapping on a file (the driver or filesystem provides and
1048 static int do_mmap_shared_file(struct vm_area_struct
*vma
)
1052 ret
= vma
->vm_file
->f_op
->mmap(vma
->vm_file
, vma
);
1054 vma
->vm_region
->vm_top
= vma
->vm_region
->vm_end
;
1060 /* getting an ENOSYS error indicates that direct mmap isn't
1061 * possible (as opposed to tried but failed) so we'll fall
1062 * through to making a private copy of the data and mapping
1068 * set up a private mapping or an anonymous shared mapping
1070 static int do_mmap_private(struct vm_area_struct
*vma
,
1071 struct vm_region
*region
,
1075 unsigned long total
, point
, n
, rlen
;
1079 /* invoke the file's mapping function so that it can keep track of
1080 * shared mappings on devices or memory
1081 * - VM_MAYSHARE will be set if it may attempt to share
1084 ret
= vma
->vm_file
->f_op
->mmap(vma
->vm_file
, vma
);
1086 /* shouldn't return success if we're not sharing */
1087 BUG_ON(!(vma
->vm_flags
& VM_MAYSHARE
));
1088 vma
->vm_region
->vm_top
= vma
->vm_region
->vm_end
;
1094 /* getting an ENOSYS error indicates that direct mmap isn't
1095 * possible (as opposed to tried but failed) so we'll try to
1096 * make a private copy of the data and map that instead */
1099 rlen
= PAGE_ALIGN(len
);
1101 /* allocate some memory to hold the mapping
1102 * - note that this may not return a page-aligned address if the object
1103 * we're allocating is smaller than a page
1105 order
= get_order(rlen
);
1106 kdebug("alloc order %d for %lx", order
, len
);
1108 pages
= alloc_pages(GFP_KERNEL
, order
);
1113 atomic_long_add(total
, &mmap_pages_allocated
);
1115 point
= rlen
>> PAGE_SHIFT
;
1117 /* we allocated a power-of-2 sized page set, so we may want to trim off
1119 if (sysctl_nr_trim_pages
&& total
- point
>= sysctl_nr_trim_pages
) {
1120 while (total
> point
) {
1121 order
= ilog2(total
- point
);
1123 kdebug("shave %lu/%lu @%lu", n
, total
- point
, total
);
1124 atomic_long_sub(n
, &mmap_pages_allocated
);
1126 set_page_refcounted(pages
+ total
);
1127 __free_pages(pages
+ total
, order
);
1131 for (point
= 1; point
< total
; point
++)
1132 set_page_refcounted(&pages
[point
]);
1134 base
= page_address(pages
);
1135 region
->vm_flags
= vma
->vm_flags
|= VM_MAPPED_COPY
;
1136 region
->vm_start
= (unsigned long) base
;
1137 region
->vm_end
= region
->vm_start
+ rlen
;
1138 region
->vm_top
= region
->vm_start
+ (total
<< PAGE_SHIFT
);
1140 vma
->vm_start
= region
->vm_start
;
1141 vma
->vm_end
= region
->vm_start
+ len
;
1144 /* read the contents of a file into the copy */
1145 mm_segment_t old_fs
;
1148 fpos
= vma
->vm_pgoff
;
1149 fpos
<<= PAGE_SHIFT
;
1153 ret
= vma
->vm_file
->f_op
->read(vma
->vm_file
, base
, rlen
, &fpos
);
1159 /* clear the last little bit */
1161 memset(base
+ ret
, 0, rlen
- ret
);
1164 /* if it's an anonymous mapping, then just clear it */
1165 memset(base
, 0, rlen
);
1171 free_page_series(region
->vm_start
, region
->vm_end
);
1172 region
->vm_start
= vma
->vm_start
= 0;
1173 region
->vm_end
= vma
->vm_end
= 0;
1178 printk("Allocation of length %lu from process %d (%s) failed\n",
1179 len
, current
->pid
, current
->comm
);
1185 * handle mapping creation for uClinux
1187 unsigned long do_mmap_pgoff(struct file
*file
,
1191 unsigned long flags
,
1192 unsigned long pgoff
)
1194 struct vm_area_struct
*vma
;
1195 struct vm_region
*region
;
1197 unsigned long capabilities
, vm_flags
, result
;
1200 kenter(",%lx,%lx,%lx,%lx,%lx", addr
, len
, prot
, flags
, pgoff
);
1202 if (!(flags
& MAP_FIXED
))
1203 addr
= round_hint_to_min(addr
);
1205 /* decide whether we should attempt the mapping, and if so what sort of
1207 ret
= validate_mmap_request(file
, addr
, len
, prot
, flags
, pgoff
,
1210 kleave(" = %d [val]", ret
);
1214 /* we've determined that we can make the mapping, now translate what we
1215 * now know into VMA flags */
1216 vm_flags
= determine_vm_flags(file
, prot
, flags
, capabilities
);
1218 /* we're going to need to record the mapping */
1219 region
= kmem_cache_zalloc(vm_region_jar
, GFP_KERNEL
);
1221 goto error_getting_region
;
1223 vma
= kmem_cache_zalloc(vm_area_cachep
, GFP_KERNEL
);
1225 goto error_getting_vma
;
1227 atomic_set(®ion
->vm_usage
, 1);
1228 region
->vm_flags
= vm_flags
;
1229 region
->vm_pgoff
= pgoff
;
1231 INIT_LIST_HEAD(&vma
->anon_vma_node
);
1232 vma
->vm_flags
= vm_flags
;
1233 vma
->vm_pgoff
= pgoff
;
1236 region
->vm_file
= file
;
1238 vma
->vm_file
= file
;
1240 if (vm_flags
& VM_EXECUTABLE
) {
1241 added_exe_file_vma(current
->mm
);
1242 vma
->vm_mm
= current
->mm
;
1246 down_write(&nommu_region_sem
);
1248 /* if we want to share, we need to check for regions created by other
1249 * mmap() calls that overlap with our proposed mapping
1250 * - we can only share with a superset match on most regular files
1251 * - shared mappings on character devices and memory backed files are
1252 * permitted to overlap inexactly as far as we are concerned for in
1253 * these cases, sharing is handled in the driver or filesystem rather
1256 if (vm_flags
& VM_MAYSHARE
) {
1257 struct vm_region
*pregion
;
1258 unsigned long pglen
, rpglen
, pgend
, rpgend
, start
;
1260 pglen
= (len
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1261 pgend
= pgoff
+ pglen
;
1263 for (rb
= rb_first(&nommu_region_tree
); rb
; rb
= rb_next(rb
)) {
1264 pregion
= rb_entry(rb
, struct vm_region
, vm_rb
);
1266 if (!(pregion
->vm_flags
& VM_MAYSHARE
))
1269 /* search for overlapping mappings on the same file */
1270 if (pregion
->vm_file
->f_path
.dentry
->d_inode
!=
1271 file
->f_path
.dentry
->d_inode
)
1274 if (pregion
->vm_pgoff
>= pgend
)
1277 rpglen
= pregion
->vm_end
- pregion
->vm_start
;
1278 rpglen
= (rpglen
+ PAGE_SIZE
- 1) >> PAGE_SHIFT
;
1279 rpgend
= pregion
->vm_pgoff
+ rpglen
;
1280 if (pgoff
>= rpgend
)
1283 /* handle inexactly overlapping matches between
1285 if ((pregion
->vm_pgoff
!= pgoff
|| rpglen
!= pglen
) &&
1286 !(pgoff
>= pregion
->vm_pgoff
&& pgend
<= rpgend
)) {
1287 /* new mapping is not a subset of the region */
1288 if (!(capabilities
& BDI_CAP_MAP_DIRECT
))
1289 goto sharing_violation
;
1293 /* we've found a region we can share */
1294 atomic_inc(&pregion
->vm_usage
);
1295 vma
->vm_region
= pregion
;
1296 start
= pregion
->vm_start
;
1297 start
+= (pgoff
- pregion
->vm_pgoff
) << PAGE_SHIFT
;
1298 vma
->vm_start
= start
;
1299 vma
->vm_end
= start
+ len
;
1301 if (pregion
->vm_flags
& VM_MAPPED_COPY
) {
1302 kdebug("share copy");
1303 vma
->vm_flags
|= VM_MAPPED_COPY
;
1305 kdebug("share mmap");
1306 ret
= do_mmap_shared_file(vma
);
1308 vma
->vm_region
= NULL
;
1311 atomic_dec(&pregion
->vm_usage
);
1313 goto error_just_free
;
1316 fput(region
->vm_file
);
1317 kmem_cache_free(vm_region_jar
, region
);
1323 /* obtain the address at which to make a shared mapping
1324 * - this is the hook for quasi-memory character devices to
1325 * tell us the location of a shared mapping
1327 if (file
&& file
->f_op
->get_unmapped_area
) {
1328 addr
= file
->f_op
->get_unmapped_area(file
, addr
, len
,
1330 if (IS_ERR((void *) addr
)) {
1332 if (ret
!= (unsigned long) -ENOSYS
)
1333 goto error_just_free
;
1335 /* the driver refused to tell us where to site
1336 * the mapping so we'll have to attempt to copy
1338 ret
= (unsigned long) -ENODEV
;
1339 if (!(capabilities
& BDI_CAP_MAP_COPY
))
1340 goto error_just_free
;
1342 capabilities
&= ~BDI_CAP_MAP_DIRECT
;
1344 vma
->vm_start
= region
->vm_start
= addr
;
1345 vma
->vm_end
= region
->vm_end
= addr
+ len
;
1350 vma
->vm_region
= region
;
1351 add_nommu_region(region
);
1353 /* set up the mapping */
1354 if (file
&& vma
->vm_flags
& VM_SHARED
)
1355 ret
= do_mmap_shared_file(vma
);
1357 ret
= do_mmap_private(vma
, region
, len
);
1359 goto error_put_region
;
1361 /* okay... we have a mapping; now we have to register it */
1362 result
= vma
->vm_start
;
1364 current
->mm
->total_vm
+= len
>> PAGE_SHIFT
;
1367 add_vma_to_mm(current
->mm
, vma
);
1369 up_write(&nommu_region_sem
);
1371 if (prot
& PROT_EXEC
)
1372 flush_icache_range(result
, result
+ len
);
1374 kleave(" = %lx", result
);
1378 __put_nommu_region(region
);
1382 if (vma
->vm_flags
& VM_EXECUTABLE
)
1383 removed_exe_file_vma(vma
->vm_mm
);
1385 kmem_cache_free(vm_area_cachep
, vma
);
1387 kleave(" = %d [pr]", ret
);
1391 up_write(&nommu_region_sem
);
1393 fput(region
->vm_file
);
1394 kmem_cache_free(vm_region_jar
, region
);
1396 if (vma
->vm_flags
& VM_EXECUTABLE
)
1397 removed_exe_file_vma(vma
->vm_mm
);
1398 kmem_cache_free(vm_area_cachep
, vma
);
1399 kleave(" = %d", ret
);
1403 up_write(&nommu_region_sem
);
1404 printk(KERN_WARNING
"Attempt to share mismatched mappings\n");
1409 kmem_cache_free(vm_region_jar
, region
);
1410 printk(KERN_WARNING
"Allocation of vma for %lu byte allocation"
1411 " from process %d failed\n",
1416 error_getting_region
:
1417 printk(KERN_WARNING
"Allocation of vm region for %lu byte allocation"
1418 " from process %d failed\n",
1423 EXPORT_SYMBOL(do_mmap_pgoff
);
1426 * split a vma into two pieces at address 'addr', a new vma is allocated either
1427 * for the first part or the tail.
1429 int split_vma(struct mm_struct
*mm
, struct vm_area_struct
*vma
,
1430 unsigned long addr
, int new_below
)
1432 struct vm_area_struct
*new;
1433 struct vm_region
*region
;
1434 unsigned long npages
;
1438 /* we're only permitted to split anonymous regions that have a single
1441 atomic_read(&vma
->vm_region
->vm_usage
) != 1)
1444 if (mm
->map_count
>= sysctl_max_map_count
)
1447 region
= kmem_cache_alloc(vm_region_jar
, GFP_KERNEL
);
1451 new = kmem_cache_alloc(vm_area_cachep
, GFP_KERNEL
);
1453 kmem_cache_free(vm_region_jar
, region
);
1457 /* most fields are the same, copy all, and then fixup */
1459 *region
= *vma
->vm_region
;
1460 new->vm_region
= region
;
1462 npages
= (addr
- vma
->vm_start
) >> PAGE_SHIFT
;
1465 region
->vm_top
= region
->vm_end
= new->vm_end
= addr
;
1467 region
->vm_start
= new->vm_start
= addr
;
1468 region
->vm_pgoff
= new->vm_pgoff
+= npages
;
1471 if (new->vm_ops
&& new->vm_ops
->open
)
1472 new->vm_ops
->open(new);
1474 delete_vma_from_mm(vma
);
1475 down_write(&nommu_region_sem
);
1476 delete_nommu_region(vma
->vm_region
);
1478 vma
->vm_region
->vm_start
= vma
->vm_start
= addr
;
1479 vma
->vm_region
->vm_pgoff
= vma
->vm_pgoff
+= npages
;
1481 vma
->vm_region
->vm_end
= vma
->vm_end
= addr
;
1482 vma
->vm_region
->vm_top
= addr
;
1484 add_nommu_region(vma
->vm_region
);
1485 add_nommu_region(new->vm_region
);
1486 up_write(&nommu_region_sem
);
1487 add_vma_to_mm(mm
, vma
);
1488 add_vma_to_mm(mm
, new);
1493 * shrink a VMA by removing the specified chunk from either the beginning or
1496 static int shrink_vma(struct mm_struct
*mm
,
1497 struct vm_area_struct
*vma
,
1498 unsigned long from
, unsigned long to
)
1500 struct vm_region
*region
;
1504 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1506 delete_vma_from_mm(vma
);
1507 if (from
> vma
->vm_start
)
1511 add_vma_to_mm(mm
, vma
);
1513 /* cut the backing region down to size */
1514 region
= vma
->vm_region
;
1515 BUG_ON(atomic_read(®ion
->vm_usage
) != 1);
1517 down_write(&nommu_region_sem
);
1518 delete_nommu_region(region
);
1519 if (from
> region
->vm_start
) {
1520 to
= region
->vm_top
;
1521 region
->vm_top
= region
->vm_end
= from
;
1523 region
->vm_start
= to
;
1525 add_nommu_region(region
);
1526 up_write(&nommu_region_sem
);
1528 free_page_series(from
, to
);
1534 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1535 * VMA, though it need not cover the whole VMA
1537 int do_munmap(struct mm_struct
*mm
, unsigned long start
, size_t len
)
1539 struct vm_area_struct
*vma
;
1541 unsigned long end
= start
+ len
;
1544 kenter(",%lx,%zx", start
, len
);
1549 /* find the first potentially overlapping VMA */
1550 vma
= find_vma(mm
, start
);
1552 static int limit
= 0;
1555 "munmap of memory not mmapped by process %d"
1556 " (%s): 0x%lx-0x%lx\n",
1557 current
->pid
, current
->comm
,
1558 start
, start
+ len
- 1);
1564 /* we're allowed to split an anonymous VMA but not a file-backed one */
1567 if (start
> vma
->vm_start
) {
1568 kleave(" = -EINVAL [miss]");
1571 if (end
== vma
->vm_end
)
1572 goto erase_whole_vma
;
1573 rb
= rb_next(&vma
->vm_rb
);
1574 vma
= rb_entry(rb
, struct vm_area_struct
, vm_rb
);
1576 kleave(" = -EINVAL [split file]");
1579 /* the chunk must be a subset of the VMA found */
1580 if (start
== vma
->vm_start
&& end
== vma
->vm_end
)
1581 goto erase_whole_vma
;
1582 if (start
< vma
->vm_start
|| end
> vma
->vm_end
) {
1583 kleave(" = -EINVAL [superset]");
1586 if (start
& ~PAGE_MASK
) {
1587 kleave(" = -EINVAL [unaligned start]");
1590 if (end
!= vma
->vm_end
&& end
& ~PAGE_MASK
) {
1591 kleave(" = -EINVAL [unaligned split]");
1594 if (start
!= vma
->vm_start
&& end
!= vma
->vm_end
) {
1595 ret
= split_vma(mm
, vma
, start
, 1);
1597 kleave(" = %d [split]", ret
);
1601 return shrink_vma(mm
, vma
, start
, end
);
1605 delete_vma_from_mm(vma
);
1606 delete_vma(mm
, vma
);
1610 EXPORT_SYMBOL(do_munmap
);
1612 SYSCALL_DEFINE2(munmap
, unsigned long, addr
, size_t, len
)
1615 struct mm_struct
*mm
= current
->mm
;
1617 down_write(&mm
->mmap_sem
);
1618 ret
= do_munmap(mm
, addr
, len
);
1619 up_write(&mm
->mmap_sem
);
1624 * release all the mappings made in a process's VM space
1626 void exit_mmap(struct mm_struct
*mm
)
1628 struct vm_area_struct
*vma
;
1637 while ((vma
= mm
->mmap
)) {
1638 mm
->mmap
= vma
->vm_next
;
1639 delete_vma_from_mm(vma
);
1640 delete_vma(mm
, vma
);
1646 unsigned long do_brk(unsigned long addr
, unsigned long len
)
1652 * expand (or shrink) an existing mapping, potentially moving it at the same
1653 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1655 * under NOMMU conditions, we only permit changing a mapping's size, and only
1656 * as long as it stays within the region allocated by do_mmap_private() and the
1657 * block is not shareable
1659 * MREMAP_FIXED is not supported under NOMMU conditions
1661 unsigned long do_mremap(unsigned long addr
,
1662 unsigned long old_len
, unsigned long new_len
,
1663 unsigned long flags
, unsigned long new_addr
)
1665 struct vm_area_struct
*vma
;
1667 /* insanity checks first */
1668 if (old_len
== 0 || new_len
== 0)
1669 return (unsigned long) -EINVAL
;
1671 if (addr
& ~PAGE_MASK
)
1674 if (flags
& MREMAP_FIXED
&& new_addr
!= addr
)
1675 return (unsigned long) -EINVAL
;
1677 vma
= find_vma_exact(current
->mm
, addr
, old_len
);
1679 return (unsigned long) -EINVAL
;
1681 if (vma
->vm_end
!= vma
->vm_start
+ old_len
)
1682 return (unsigned long) -EFAULT
;
1684 if (vma
->vm_flags
& VM_MAYSHARE
)
1685 return (unsigned long) -EPERM
;
1687 if (new_len
> vma
->vm_region
->vm_end
- vma
->vm_region
->vm_start
)
1688 return (unsigned long) -ENOMEM
;
1690 /* all checks complete - do it */
1691 vma
->vm_end
= vma
->vm_start
+ new_len
;
1692 return vma
->vm_start
;
1694 EXPORT_SYMBOL(do_mremap
);
1696 SYSCALL_DEFINE5(mremap
, unsigned long, addr
, unsigned long, old_len
,
1697 unsigned long, new_len
, unsigned long, flags
,
1698 unsigned long, new_addr
)
1702 down_write(¤t
->mm
->mmap_sem
);
1703 ret
= do_mremap(addr
, old_len
, new_len
, flags
, new_addr
);
1704 up_write(¤t
->mm
->mmap_sem
);
1708 struct page
*follow_page(struct vm_area_struct
*vma
, unsigned long address
,
1709 unsigned int foll_flags
)
1714 int remap_pfn_range(struct vm_area_struct
*vma
, unsigned long from
,
1715 unsigned long to
, unsigned long size
, pgprot_t prot
)
1717 vma
->vm_start
= vma
->vm_pgoff
<< PAGE_SHIFT
;
1720 EXPORT_SYMBOL(remap_pfn_range
);
1722 int remap_vmalloc_range(struct vm_area_struct
*vma
, void *addr
,
1723 unsigned long pgoff
)
1725 unsigned int size
= vma
->vm_end
- vma
->vm_start
;
1727 if (!(vma
->vm_flags
& VM_USERMAP
))
1730 vma
->vm_start
= (unsigned long)(addr
+ (pgoff
<< PAGE_SHIFT
));
1731 vma
->vm_end
= vma
->vm_start
+ size
;
1735 EXPORT_SYMBOL(remap_vmalloc_range
);
1737 void swap_unplug_io_fn(struct backing_dev_info
*bdi
, struct page
*page
)
1741 unsigned long arch_get_unmapped_area(struct file
*file
, unsigned long addr
,
1742 unsigned long len
, unsigned long pgoff
, unsigned long flags
)
1747 void arch_unmap_area(struct mm_struct
*mm
, unsigned long addr
)
1751 void unmap_mapping_range(struct address_space
*mapping
,
1752 loff_t
const holebegin
, loff_t
const holelen
,
1756 EXPORT_SYMBOL(unmap_mapping_range
);
1759 * ask for an unmapped area at which to create a mapping on a file
1761 unsigned long get_unmapped_area(struct file
*file
, unsigned long addr
,
1762 unsigned long len
, unsigned long pgoff
,
1763 unsigned long flags
)
1765 unsigned long (*get_area
)(struct file
*, unsigned long, unsigned long,
1766 unsigned long, unsigned long);
1768 get_area
= current
->mm
->get_unmapped_area
;
1769 if (file
&& file
->f_op
&& file
->f_op
->get_unmapped_area
)
1770 get_area
= file
->f_op
->get_unmapped_area
;
1775 return get_area(file
, addr
, len
, pgoff
, flags
);
1777 EXPORT_SYMBOL(get_unmapped_area
);
1780 * Check that a process has enough memory to allocate a new virtual
1781 * mapping. 0 means there is enough memory for the allocation to
1782 * succeed and -ENOMEM implies there is not.
1784 * We currently support three overcommit policies, which are set via the
1785 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1787 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1788 * Additional code 2002 Jul 20 by Robert Love.
1790 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1792 * Note this is a helper function intended to be used by LSMs which
1793 * wish to use this logic.
1795 int __vm_enough_memory(struct mm_struct
*mm
, long pages
, int cap_sys_admin
)
1797 unsigned long free
, allowed
;
1799 vm_acct_memory(pages
);
1802 * Sometimes we want to use more memory than we have
1804 if (sysctl_overcommit_memory
== OVERCOMMIT_ALWAYS
)
1807 if (sysctl_overcommit_memory
== OVERCOMMIT_GUESS
) {
1810 free
= global_page_state(NR_FILE_PAGES
);
1811 free
+= nr_swap_pages
;
1814 * Any slabs which are created with the
1815 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1816 * which are reclaimable, under pressure. The dentry
1817 * cache and most inode caches should fall into this
1819 free
+= global_page_state(NR_SLAB_RECLAIMABLE
);
1822 * Leave the last 3% for root
1831 * nr_free_pages() is very expensive on large systems,
1832 * only call if we're about to fail.
1834 n
= nr_free_pages();
1837 * Leave reserved pages. The pages are not for anonymous pages.
1839 if (n
<= totalreserve_pages
)
1842 n
-= totalreserve_pages
;
1845 * Leave the last 3% for root
1857 allowed
= totalram_pages
* sysctl_overcommit_ratio
/ 100;
1859 * Leave the last 3% for root
1862 allowed
-= allowed
/ 32;
1863 allowed
+= total_swap_pages
;
1865 /* Don't let a single process grow too big:
1866 leave 3% of the size of this process for other processes */
1868 allowed
-= mm
->total_vm
/ 32;
1870 if (percpu_counter_read_positive(&vm_committed_as
) < allowed
)
1874 vm_unacct_memory(pages
);
1879 int in_gate_area_no_task(unsigned long addr
)
1884 int filemap_fault(struct vm_area_struct
*vma
, struct vm_fault
*vmf
)
1889 EXPORT_SYMBOL(filemap_fault
);
1892 * Access another process' address space.
1893 * - source/target buffer must be kernel space
1895 int access_process_vm(struct task_struct
*tsk
, unsigned long addr
, void *buf
, int len
, int write
)
1897 struct vm_area_struct
*vma
;
1898 struct mm_struct
*mm
;
1900 if (addr
+ len
< addr
)
1903 mm
= get_task_mm(tsk
);
1907 down_read(&mm
->mmap_sem
);
1909 /* the access must start within one of the target process's mappings */
1910 vma
= find_vma(mm
, addr
);
1912 /* don't overrun this mapping */
1913 if (addr
+ len
>= vma
->vm_end
)
1914 len
= vma
->vm_end
- addr
;
1916 /* only read or write mappings where it is permitted */
1917 if (write
&& vma
->vm_flags
& VM_MAYWRITE
)
1918 len
-= copy_to_user((void *) addr
, buf
, len
);
1919 else if (!write
&& vma
->vm_flags
& VM_MAYREAD
)
1920 len
-= copy_from_user(buf
, (void *) addr
, len
);
1927 up_read(&mm
->mmap_sem
);