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 #include <linux/export.h>
18 #include <linux/vmacache.h>
19 #include <linux/mman.h>
20 #include <linux/swap.h>
21 #include <linux/file.h>
22 #include <linux/highmem.h>
23 #include <linux/pagemap.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/blkdev.h>
27 #include <linux/backing-dev.h>
28 #include <linux/compiler.h>
29 #include <linux/mount.h>
30 #include <linux/personality.h>
31 #include <linux/security.h>
32 #include <linux/syscalls.h>
33 #include <linux/audit.h>
34 #include <linux/sched/sysctl.h>
36 #include <asm/uaccess.h>
38 #include <asm/tlbflush.h>
39 #include <asm/mmu_context.h>
43 #define kenter(FMT, ...) \
44 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
45 #define kleave(FMT, ...) \
46 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
47 #define kdebug(FMT, ...) \
48 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
50 #define kenter(FMT, ...) \
51 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
52 #define kleave(FMT, ...) \
53 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
54 #define kdebug(FMT, ...) \
55 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
60 unsigned long max_mapnr;
61 unsigned long highest_memmap_pfn;
62 struct percpu_counter vm_committed_as;
63 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
64 int sysctl_overcommit_ratio = 50; /* default is 50% */
65 unsigned long sysctl_overcommit_kbytes __read_mostly;
66 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
67 int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
68 unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
69 unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
70 int heap_stack_gap = 0;
72 atomic_long_t mmap_pages_allocated;
75 * The global memory commitment made in the system can be a metric
76 * that can be used to drive ballooning decisions when Linux is hosted
77 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
78 * balancing memory across competing virtual machines that are hosted.
79 * Several metrics drive this policy engine including the guest reported
82 unsigned long vm_memory_committed(void)
84 return percpu_counter_read_positive(&vm_committed_as);
87 EXPORT_SYMBOL_GPL(vm_memory_committed);
89 EXPORT_SYMBOL(mem_map);
91 /* list of mapped, potentially shareable regions */
92 static struct kmem_cache *vm_region_jar;
93 struct rb_root nommu_region_tree = RB_ROOT;
94 DECLARE_RWSEM(nommu_region_sem);
96 const struct vm_operations_struct generic_file_vm_ops = {
100 * Return the total memory allocated for this pointer, not
101 * just what the caller asked for.
103 * Doesn't have to be accurate, i.e. may have races.
105 unsigned int kobjsize(const void *objp)
110 * If the object we have should not have ksize performed on it,
113 if (!objp || !virt_addr_valid(objp))
116 page = virt_to_head_page(objp);
119 * If the allocator sets PageSlab, we know the pointer came from
126 * If it's not a compound page, see if we have a matching VMA
127 * region. This test is intentionally done in reverse order,
128 * so if there's no VMA, we still fall through and hand back
129 * PAGE_SIZE for 0-order pages.
131 if (!PageCompound(page)) {
132 struct vm_area_struct *vma;
134 vma = find_vma(current->mm, (unsigned long)objp);
136 return vma->vm_end - vma->vm_start;
140 * The ksize() function is only guaranteed to work for pointers
141 * returned by kmalloc(). So handle arbitrary pointers here.
143 return PAGE_SIZE << compound_order(page);
146 long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
147 unsigned long start, unsigned long nr_pages,
148 unsigned int foll_flags, struct page **pages,
149 struct vm_area_struct **vmas, int *nonblocking)
151 struct vm_area_struct *vma;
152 unsigned long vm_flags;
155 /* calculate required read or write permissions.
156 * If FOLL_FORCE is set, we only require the "MAY" flags.
158 vm_flags = (foll_flags & FOLL_WRITE) ?
159 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
160 vm_flags &= (foll_flags & FOLL_FORCE) ?
161 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
163 for (i = 0; i < nr_pages; i++) {
164 vma = find_vma(mm, start);
166 goto finish_or_fault;
168 /* protect what we can, including chardevs */
169 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
170 !(vm_flags & vma->vm_flags))
171 goto finish_or_fault;
174 pages[i] = virt_to_page(start);
176 page_cache_get(pages[i]);
180 start = (start + PAGE_SIZE) & PAGE_MASK;
186 return i ? : -EFAULT;
190 * get a list of pages in an address range belonging to the specified process
191 * and indicate the VMA that covers each page
192 * - this is potentially dodgy as we may end incrementing the page count of a
193 * slab page or a secondary page from a compound page
194 * - don't permit access to VMAs that don't support it, such as I/O mappings
196 long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
197 unsigned long start, unsigned long nr_pages,
198 int write, int force, struct page **pages,
199 struct vm_area_struct **vmas)
208 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
211 EXPORT_SYMBOL(get_user_pages);
214 * follow_pfn - look up PFN at a user virtual address
215 * @vma: memory mapping
216 * @address: user virtual address
217 * @pfn: location to store found PFN
219 * Only IO mappings and raw PFN mappings are allowed.
221 * Returns zero and the pfn at @pfn on success, -ve otherwise.
223 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
226 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
229 *pfn = address >> PAGE_SHIFT;
232 EXPORT_SYMBOL(follow_pfn);
234 LIST_HEAD(vmap_area_list);
236 void vfree(const void *addr)
240 EXPORT_SYMBOL(vfree);
242 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
245 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
246 * returns only a logical address.
248 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
250 EXPORT_SYMBOL(__vmalloc);
252 void *vmalloc_user(unsigned long size)
256 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
259 struct vm_area_struct *vma;
261 down_write(¤t->mm->mmap_sem);
262 vma = find_vma(current->mm, (unsigned long)ret);
264 vma->vm_flags |= VM_USERMAP;
265 up_write(¤t->mm->mmap_sem);
270 EXPORT_SYMBOL(vmalloc_user);
272 struct page *vmalloc_to_page(const void *addr)
274 return virt_to_page(addr);
276 EXPORT_SYMBOL(vmalloc_to_page);
278 unsigned long vmalloc_to_pfn(const void *addr)
280 return page_to_pfn(virt_to_page(addr));
282 EXPORT_SYMBOL(vmalloc_to_pfn);
284 long vread(char *buf, char *addr, unsigned long count)
286 /* Don't allow overflow */
287 if ((unsigned long) buf + count < count)
288 count = -(unsigned long) buf;
290 memcpy(buf, addr, count);
294 long vwrite(char *buf, char *addr, unsigned long count)
296 /* Don't allow overflow */
297 if ((unsigned long) addr + count < count)
298 count = -(unsigned long) addr;
300 memcpy(addr, buf, count);
305 * vmalloc - allocate virtually continguos memory
307 * @size: allocation size
309 * Allocate enough pages to cover @size from the page level
310 * allocator and map them into continguos kernel virtual space.
312 * For tight control over page level allocator and protection flags
313 * use __vmalloc() instead.
315 void *vmalloc(unsigned long size)
317 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
319 EXPORT_SYMBOL(vmalloc);
322 * vzalloc - allocate virtually continguos memory with zero fill
324 * @size: allocation size
326 * Allocate enough pages to cover @size from the page level
327 * allocator and map them into continguos kernel virtual space.
328 * The memory allocated is set to zero.
330 * For tight control over page level allocator and protection flags
331 * use __vmalloc() instead.
333 void *vzalloc(unsigned long size)
335 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
338 EXPORT_SYMBOL(vzalloc);
341 * vmalloc_node - allocate memory on a specific node
342 * @size: allocation size
345 * Allocate enough pages to cover @size from the page level
346 * allocator and map them into contiguous kernel virtual space.
348 * For tight control over page level allocator and protection flags
349 * use __vmalloc() instead.
351 void *vmalloc_node(unsigned long size, int node)
353 return vmalloc(size);
355 EXPORT_SYMBOL(vmalloc_node);
358 * vzalloc_node - allocate memory on a specific node with zero fill
359 * @size: allocation size
362 * Allocate enough pages to cover @size from the page level
363 * allocator and map them into contiguous kernel virtual space.
364 * The memory allocated is set to zero.
366 * For tight control over page level allocator and protection flags
367 * use __vmalloc() instead.
369 void *vzalloc_node(unsigned long size, int node)
371 return vzalloc(size);
373 EXPORT_SYMBOL(vzalloc_node);
375 #ifndef PAGE_KERNEL_EXEC
376 # define PAGE_KERNEL_EXEC PAGE_KERNEL
380 * vmalloc_exec - allocate virtually contiguous, executable memory
381 * @size: allocation size
383 * Kernel-internal function to allocate enough pages to cover @size
384 * the page level allocator and map them into contiguous and
385 * executable kernel virtual space.
387 * For tight control over page level allocator and protection flags
388 * use __vmalloc() instead.
391 void *vmalloc_exec(unsigned long size)
393 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
397 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
398 * @size: allocation size
400 * Allocate enough 32bit PA addressable pages to cover @size from the
401 * page level allocator and map them into continguos kernel virtual space.
403 void *vmalloc_32(unsigned long size)
405 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
407 EXPORT_SYMBOL(vmalloc_32);
410 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
411 * @size: allocation size
413 * The resulting memory area is 32bit addressable and zeroed so it can be
414 * mapped to userspace without leaking data.
416 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
417 * remap_vmalloc_range() are permissible.
419 void *vmalloc_32_user(unsigned long size)
422 * We'll have to sort out the ZONE_DMA bits for 64-bit,
423 * but for now this can simply use vmalloc_user() directly.
425 return vmalloc_user(size);
427 EXPORT_SYMBOL(vmalloc_32_user);
429 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
436 void vunmap(const void *addr)
440 EXPORT_SYMBOL(vunmap);
442 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
447 EXPORT_SYMBOL(vm_map_ram);
449 void vm_unmap_ram(const void *mem, unsigned int count)
453 EXPORT_SYMBOL(vm_unmap_ram);
455 void vm_unmap_aliases(void)
458 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
461 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
464 void __weak vmalloc_sync_all(void)
469 * alloc_vm_area - allocate a range of kernel address space
470 * @size: size of the area
472 * Returns: NULL on failure, vm_struct on success
474 * This function reserves a range of kernel address space, and
475 * allocates pagetables to map that range. No actual mappings
476 * are created. If the kernel address space is not shared
477 * between processes, it syncs the pagetable across all
480 struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
485 EXPORT_SYMBOL_GPL(alloc_vm_area);
487 void free_vm_area(struct vm_struct *area)
491 EXPORT_SYMBOL_GPL(free_vm_area);
493 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
498 EXPORT_SYMBOL(vm_insert_page);
501 * sys_brk() for the most part doesn't need the global kernel
502 * lock, except when an application is doing something nasty
503 * like trying to un-brk an area that has already been mapped
504 * to a regular file. in this case, the unmapping will need
505 * to invoke file system routines that need the global lock.
507 SYSCALL_DEFINE1(brk, unsigned long, brk)
509 struct mm_struct *mm = current->mm;
511 if (brk < mm->start_brk || brk > mm->context.end_brk)
518 * Always allow shrinking brk
520 if (brk <= mm->brk) {
526 * Ok, looks good - let it rip.
528 flush_icache_range(mm->brk, brk);
529 return mm->brk = brk;
533 * initialise the VMA and region record slabs
535 void __init mmap_init(void)
539 ret = percpu_counter_init(&vm_committed_as, 0);
541 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
545 * validate the region tree
546 * - the caller must hold the region lock
548 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
549 static noinline void validate_nommu_regions(void)
551 struct vm_region *region, *last;
552 struct rb_node *p, *lastp;
554 lastp = rb_first(&nommu_region_tree);
558 last = rb_entry(lastp, struct vm_region, vm_rb);
559 BUG_ON(unlikely(last->vm_end <= last->vm_start));
560 BUG_ON(unlikely(last->vm_top < last->vm_end));
562 while ((p = rb_next(lastp))) {
563 region = rb_entry(p, struct vm_region, vm_rb);
564 last = rb_entry(lastp, struct vm_region, vm_rb);
566 BUG_ON(unlikely(region->vm_end <= region->vm_start));
567 BUG_ON(unlikely(region->vm_top < region->vm_end));
568 BUG_ON(unlikely(region->vm_start < last->vm_top));
574 static void validate_nommu_regions(void)
580 * add a region into the global tree
582 static void add_nommu_region(struct vm_region *region)
584 struct vm_region *pregion;
585 struct rb_node **p, *parent;
587 validate_nommu_regions();
590 p = &nommu_region_tree.rb_node;
593 pregion = rb_entry(parent, struct vm_region, vm_rb);
594 if (region->vm_start < pregion->vm_start)
596 else if (region->vm_start > pregion->vm_start)
598 else if (pregion == region)
604 rb_link_node(®ion->vm_rb, parent, p);
605 rb_insert_color(®ion->vm_rb, &nommu_region_tree);
607 validate_nommu_regions();
611 * delete a region from the global tree
613 static void delete_nommu_region(struct vm_region *region)
615 BUG_ON(!nommu_region_tree.rb_node);
617 validate_nommu_regions();
618 rb_erase(®ion->vm_rb, &nommu_region_tree);
619 validate_nommu_regions();
623 * free a contiguous series of pages
625 static void free_page_series(unsigned long from, unsigned long to)
627 for (; from < to; from += PAGE_SIZE) {
628 struct page *page = virt_to_page(from);
630 kdebug("- free %lx", from);
631 atomic_long_dec(&mmap_pages_allocated);
632 if (page_count(page) != 1)
633 kdebug("free page %p: refcount not one: %d",
634 page, page_count(page));
640 * release a reference to a region
641 * - the caller must hold the region semaphore for writing, which this releases
642 * - the region may not have been added to the tree yet, in which case vm_top
643 * will equal vm_start
645 static void __put_nommu_region(struct vm_region *region)
646 __releases(nommu_region_sem)
648 kenter("%p{%d}", region, region->vm_usage);
650 BUG_ON(!nommu_region_tree.rb_node);
652 if (--region->vm_usage == 0) {
653 if (region->vm_top > region->vm_start)
654 delete_nommu_region(region);
655 up_write(&nommu_region_sem);
658 fput(region->vm_file);
660 /* IO memory and memory shared directly out of the pagecache
661 * from ramfs/tmpfs mustn't be released here */
662 if (region->vm_flags & VM_MAPPED_COPY) {
663 kdebug("free series");
664 free_page_series(region->vm_start, region->vm_top);
666 kmem_cache_free(vm_region_jar, region);
668 up_write(&nommu_region_sem);
673 * release a reference to a region
675 static void put_nommu_region(struct vm_region *region)
677 down_write(&nommu_region_sem);
678 __put_nommu_region(region);
682 * update protection on a vma
684 static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
687 struct mm_struct *mm = vma->vm_mm;
688 long start = vma->vm_start & PAGE_MASK;
689 while (start < vma->vm_end) {
690 protect_page(mm, start, flags);
693 update_protections(mm);
698 * add a VMA into a process's mm_struct in the appropriate place in the list
699 * and tree and add to the address space's page tree also if not an anonymous
701 * - should be called with mm->mmap_sem held writelocked
703 static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
705 struct vm_area_struct *pvma, *prev;
706 struct address_space *mapping;
707 struct rb_node **p, *parent, *rb_prev;
711 BUG_ON(!vma->vm_region);
716 protect_vma(vma, vma->vm_flags);
718 /* add the VMA to the mapping */
720 mapping = vma->vm_file->f_mapping;
722 mutex_lock(&mapping->i_mmap_mutex);
723 flush_dcache_mmap_lock(mapping);
724 vma_interval_tree_insert(vma, &mapping->i_mmap);
725 flush_dcache_mmap_unlock(mapping);
726 mutex_unlock(&mapping->i_mmap_mutex);
729 /* add the VMA to the tree */
730 parent = rb_prev = NULL;
731 p = &mm->mm_rb.rb_node;
734 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
736 /* sort by: start addr, end addr, VMA struct addr in that order
737 * (the latter is necessary as we may get identical VMAs) */
738 if (vma->vm_start < pvma->vm_start)
740 else if (vma->vm_start > pvma->vm_start) {
743 } else if (vma->vm_end < pvma->vm_end)
745 else if (vma->vm_end > pvma->vm_end) {
748 } else if (vma < pvma)
750 else if (vma > pvma) {
757 rb_link_node(&vma->vm_rb, parent, p);
758 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
760 /* add VMA to the VMA list also */
763 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
765 __vma_link_list(mm, vma, prev, parent);
769 * delete a VMA from its owning mm_struct and address space
771 static void delete_vma_from_mm(struct vm_area_struct *vma)
774 struct address_space *mapping;
775 struct mm_struct *mm = vma->vm_mm;
776 struct task_struct *curr = current;
783 for (i = 0; i < VMACACHE_SIZE; i++) {
784 /* if the vma is cached, invalidate the entire cache */
785 if (curr->vmacache[i] == vma) {
786 vmacache_invalidate(curr->mm);
791 /* remove the VMA from the mapping */
793 mapping = vma->vm_file->f_mapping;
795 mutex_lock(&mapping->i_mmap_mutex);
796 flush_dcache_mmap_lock(mapping);
797 vma_interval_tree_remove(vma, &mapping->i_mmap);
798 flush_dcache_mmap_unlock(mapping);
799 mutex_unlock(&mapping->i_mmap_mutex);
802 /* remove from the MM's tree and list */
803 rb_erase(&vma->vm_rb, &mm->mm_rb);
806 vma->vm_prev->vm_next = vma->vm_next;
808 mm->mmap = vma->vm_next;
811 vma->vm_next->vm_prev = vma->vm_prev;
815 * destroy a VMA record
817 static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
820 if (vma->vm_ops && vma->vm_ops->close)
821 vma->vm_ops->close(vma);
824 put_nommu_region(vma->vm_region);
825 kmem_cache_free(vm_area_cachep, vma);
829 * look up the first VMA in which addr resides, NULL if none
830 * - should be called with mm->mmap_sem at least held readlocked
832 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
834 struct vm_area_struct *vma;
836 /* check the cache first */
837 vma = vmacache_find(mm, addr);
841 /* trawl the list (there may be multiple mappings in which addr
843 for (vma = mm->mmap; vma; vma = vma->vm_next) {
844 if (vma->vm_start > addr)
846 if (vma->vm_end > addr) {
847 vmacache_update(addr, vma);
854 EXPORT_SYMBOL(find_vma);
858 * - we don't extend stack VMAs under NOMMU conditions
860 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
862 return find_vma(mm, addr);
866 * expand a stack to a given address
867 * - not supported under NOMMU conditions
869 int expand_stack(struct vm_area_struct *vma, unsigned long address)
875 * look up the first VMA exactly that exactly matches addr
876 * - should be called with mm->mmap_sem at least held readlocked
878 static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
882 struct vm_area_struct *vma;
883 unsigned long end = addr + len;
885 /* check the cache first */
886 vma = vmacache_find_exact(mm, addr, end);
890 /* trawl the list (there may be multiple mappings in which addr
892 for (vma = mm->mmap; vma; vma = vma->vm_next) {
893 if (vma->vm_start < addr)
895 if (vma->vm_start > addr)
897 if (vma->vm_end == end) {
898 vmacache_update(addr, vma);
907 * determine whether a mapping should be permitted and, if so, what sort of
908 * mapping we're capable of supporting
910 static int validate_mmap_request(struct file *file,
916 unsigned long *_capabilities)
918 unsigned long capabilities, rlen;
921 /* do the simple checks first */
922 if (flags & MAP_FIXED) {
924 "%d: Can't do fixed-address/overlay mmap of RAM\n",
929 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
930 (flags & MAP_TYPE) != MAP_SHARED)
936 /* Careful about overflows.. */
937 rlen = PAGE_ALIGN(len);
938 if (!rlen || rlen > TASK_SIZE)
941 /* offset overflow? */
942 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
946 /* validate file mapping requests */
947 struct address_space *mapping;
949 /* files must support mmap */
950 if (!file->f_op->mmap)
953 /* work out if what we've got could possibly be shared
954 * - we support chardevs that provide their own "memory"
955 * - we support files/blockdevs that are memory backed
957 mapping = file->f_mapping;
959 mapping = file_inode(file)->i_mapping;
962 if (mapping && mapping->backing_dev_info)
963 capabilities = mapping->backing_dev_info->capabilities;
966 /* no explicit capabilities set, so assume some
968 switch (file_inode(file)->i_mode & S_IFMT) {
971 capabilities = BDI_CAP_MAP_COPY;
986 /* eliminate any capabilities that we can't support on this
988 if (!file->f_op->get_unmapped_area)
989 capabilities &= ~BDI_CAP_MAP_DIRECT;
990 if (!file->f_op->read)
991 capabilities &= ~BDI_CAP_MAP_COPY;
993 /* The file shall have been opened with read permission. */
994 if (!(file->f_mode & FMODE_READ))
997 if (flags & MAP_SHARED) {
998 /* do checks for writing, appending and locking */
999 if ((prot & PROT_WRITE) &&
1000 !(file->f_mode & FMODE_WRITE))
1003 if (IS_APPEND(file_inode(file)) &&
1004 (file->f_mode & FMODE_WRITE))
1007 if (locks_verify_locked(file))
1010 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1013 /* we mustn't privatise shared mappings */
1014 capabilities &= ~BDI_CAP_MAP_COPY;
1017 /* we're going to read the file into private memory we
1019 if (!(capabilities & BDI_CAP_MAP_COPY))
1022 /* we don't permit a private writable mapping to be
1023 * shared with the backing device */
1024 if (prot & PROT_WRITE)
1025 capabilities &= ~BDI_CAP_MAP_DIRECT;
1028 if (capabilities & BDI_CAP_MAP_DIRECT) {
1029 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
1030 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
1031 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
1033 capabilities &= ~BDI_CAP_MAP_DIRECT;
1034 if (flags & MAP_SHARED) {
1036 "MAP_SHARED not completely supported on !MMU\n");
1042 /* handle executable mappings and implied executable
1044 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
1045 if (prot & PROT_EXEC)
1048 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
1049 /* handle implication of PROT_EXEC by PROT_READ */
1050 if (current->personality & READ_IMPLIES_EXEC) {
1051 if (capabilities & BDI_CAP_EXEC_MAP)
1055 else if ((prot & PROT_READ) &&
1056 (prot & PROT_EXEC) &&
1057 !(capabilities & BDI_CAP_EXEC_MAP)
1059 /* backing file is not executable, try to copy */
1060 capabilities &= ~BDI_CAP_MAP_DIRECT;
1064 /* anonymous mappings are always memory backed and can be
1067 capabilities = BDI_CAP_MAP_COPY;
1069 /* handle PROT_EXEC implication by PROT_READ */
1070 if ((prot & PROT_READ) &&
1071 (current->personality & READ_IMPLIES_EXEC))
1075 /* allow the security API to have its say */
1076 ret = security_mmap_addr(addr);
1081 *_capabilities = capabilities;
1086 * we've determined that we can make the mapping, now translate what we
1087 * now know into VMA flags
1089 static unsigned long determine_vm_flags(struct file *file,
1091 unsigned long flags,
1092 unsigned long capabilities)
1094 unsigned long vm_flags;
1096 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
1097 /* vm_flags |= mm->def_flags; */
1099 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1100 /* attempt to share read-only copies of mapped file chunks */
1101 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1102 if (file && !(prot & PROT_WRITE))
1103 vm_flags |= VM_MAYSHARE;
1105 /* overlay a shareable mapping on the backing device or inode
1106 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1108 vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS);
1109 if (flags & MAP_SHARED)
1110 vm_flags |= VM_SHARED;
1113 /* refuse to let anyone share private mappings with this process if
1114 * it's being traced - otherwise breakpoints set in it may interfere
1115 * with another untraced process
1117 if ((flags & MAP_PRIVATE) && current->ptrace)
1118 vm_flags &= ~VM_MAYSHARE;
1124 * set up a shared mapping on a file (the driver or filesystem provides and
1127 static int do_mmap_shared_file(struct vm_area_struct *vma)
1131 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1133 vma->vm_region->vm_top = vma->vm_region->vm_end;
1139 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1140 * opposed to tried but failed) so we can only give a suitable error as
1141 * it's not possible to make a private copy if MAP_SHARED was given */
1146 * set up a private mapping or an anonymous shared mapping
1148 static int do_mmap_private(struct vm_area_struct *vma,
1149 struct vm_region *region,
1151 unsigned long capabilities)
1154 unsigned long total, point, n;
1158 /* invoke the file's mapping function so that it can keep track of
1159 * shared mappings on devices or memory
1160 * - VM_MAYSHARE will be set if it may attempt to share
1162 if (capabilities & BDI_CAP_MAP_DIRECT) {
1163 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1165 /* shouldn't return success if we're not sharing */
1166 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1167 vma->vm_region->vm_top = vma->vm_region->vm_end;
1173 /* getting an ENOSYS error indicates that direct mmap isn't
1174 * possible (as opposed to tried but failed) so we'll try to
1175 * make a private copy of the data and map that instead */
1179 /* allocate some memory to hold the mapping
1180 * - note that this may not return a page-aligned address if the object
1181 * we're allocating is smaller than a page
1183 order = get_order(len);
1184 kdebug("alloc order %d for %lx", order, len);
1186 pages = alloc_pages(GFP_KERNEL, order);
1191 atomic_long_add(total, &mmap_pages_allocated);
1193 point = len >> PAGE_SHIFT;
1195 /* we allocated a power-of-2 sized page set, so we may want to trim off
1197 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1198 while (total > point) {
1199 order = ilog2(total - point);
1201 kdebug("shave %lu/%lu @%lu", n, total - point, total);
1202 atomic_long_sub(n, &mmap_pages_allocated);
1204 set_page_refcounted(pages + total);
1205 __free_pages(pages + total, order);
1209 for (point = 1; point < total; point++)
1210 set_page_refcounted(&pages[point]);
1212 base = page_address(pages);
1213 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1214 region->vm_start = (unsigned long) base;
1215 region->vm_end = region->vm_start + len;
1216 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1218 vma->vm_start = region->vm_start;
1219 vma->vm_end = region->vm_start + len;
1222 /* read the contents of a file into the copy */
1223 mm_segment_t old_fs;
1226 fpos = vma->vm_pgoff;
1227 fpos <<= PAGE_SHIFT;
1231 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
1237 /* clear the last little bit */
1239 memset(base + ret, 0, len - ret);
1246 free_page_series(region->vm_start, region->vm_top);
1247 region->vm_start = vma->vm_start = 0;
1248 region->vm_end = vma->vm_end = 0;
1253 printk("Allocation of length %lu from process %d (%s) failed\n",
1254 len, current->pid, current->comm);
1260 * handle mapping creation for uClinux
1262 unsigned long do_mmap_pgoff(struct file *file,
1266 unsigned long flags,
1267 unsigned long pgoff,
1268 unsigned long *populate)
1270 struct vm_area_struct *vma;
1271 struct vm_region *region;
1273 unsigned long capabilities, vm_flags, result;
1276 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1280 /* decide whether we should attempt the mapping, and if so what sort of
1282 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1285 kleave(" = %d [val]", ret);
1289 /* we ignore the address hint */
1291 len = PAGE_ALIGN(len);
1293 /* we've determined that we can make the mapping, now translate what we
1294 * now know into VMA flags */
1295 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1297 /* we're going to need to record the mapping */
1298 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1300 goto error_getting_region;
1302 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1304 goto error_getting_vma;
1306 region->vm_usage = 1;
1307 region->vm_flags = vm_flags;
1308 region->vm_pgoff = pgoff;
1310 INIT_LIST_HEAD(&vma->anon_vma_chain);
1311 vma->vm_flags = vm_flags;
1312 vma->vm_pgoff = pgoff;
1315 region->vm_file = get_file(file);
1316 vma->vm_file = get_file(file);
1319 down_write(&nommu_region_sem);
1321 /* if we want to share, we need to check for regions created by other
1322 * mmap() calls that overlap with our proposed mapping
1323 * - we can only share with a superset match on most regular files
1324 * - shared mappings on character devices and memory backed files are
1325 * permitted to overlap inexactly as far as we are concerned for in
1326 * these cases, sharing is handled in the driver or filesystem rather
1329 if (vm_flags & VM_MAYSHARE) {
1330 struct vm_region *pregion;
1331 unsigned long pglen, rpglen, pgend, rpgend, start;
1333 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1334 pgend = pgoff + pglen;
1336 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1337 pregion = rb_entry(rb, struct vm_region, vm_rb);
1339 if (!(pregion->vm_flags & VM_MAYSHARE))
1342 /* search for overlapping mappings on the same file */
1343 if (file_inode(pregion->vm_file) !=
1347 if (pregion->vm_pgoff >= pgend)
1350 rpglen = pregion->vm_end - pregion->vm_start;
1351 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1352 rpgend = pregion->vm_pgoff + rpglen;
1353 if (pgoff >= rpgend)
1356 /* handle inexactly overlapping matches between
1358 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1359 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1360 /* new mapping is not a subset of the region */
1361 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1362 goto sharing_violation;
1366 /* we've found a region we can share */
1367 pregion->vm_usage++;
1368 vma->vm_region = pregion;
1369 start = pregion->vm_start;
1370 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1371 vma->vm_start = start;
1372 vma->vm_end = start + len;
1374 if (pregion->vm_flags & VM_MAPPED_COPY) {
1375 kdebug("share copy");
1376 vma->vm_flags |= VM_MAPPED_COPY;
1378 kdebug("share mmap");
1379 ret = do_mmap_shared_file(vma);
1381 vma->vm_region = NULL;
1384 pregion->vm_usage--;
1386 goto error_just_free;
1389 fput(region->vm_file);
1390 kmem_cache_free(vm_region_jar, region);
1396 /* obtain the address at which to make a shared mapping
1397 * - this is the hook for quasi-memory character devices to
1398 * tell us the location of a shared mapping
1400 if (capabilities & BDI_CAP_MAP_DIRECT) {
1401 addr = file->f_op->get_unmapped_area(file, addr, len,
1403 if (IS_ERR_VALUE(addr)) {
1406 goto error_just_free;
1408 /* the driver refused to tell us where to site
1409 * the mapping so we'll have to attempt to copy
1412 if (!(capabilities & BDI_CAP_MAP_COPY))
1413 goto error_just_free;
1415 capabilities &= ~BDI_CAP_MAP_DIRECT;
1417 vma->vm_start = region->vm_start = addr;
1418 vma->vm_end = region->vm_end = addr + len;
1423 vma->vm_region = region;
1425 /* set up the mapping
1426 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1428 if (file && vma->vm_flags & VM_SHARED)
1429 ret = do_mmap_shared_file(vma);
1431 ret = do_mmap_private(vma, region, len, capabilities);
1433 goto error_just_free;
1434 add_nommu_region(region);
1436 /* clear anonymous mappings that don't ask for uninitialized data */
1437 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1438 memset((void *)region->vm_start, 0,
1439 region->vm_end - region->vm_start);
1441 /* okay... we have a mapping; now we have to register it */
1442 result = vma->vm_start;
1444 current->mm->total_vm += len >> PAGE_SHIFT;
1447 add_vma_to_mm(current->mm, vma);
1449 /* we flush the region from the icache only when the first executable
1450 * mapping of it is made */
1451 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1452 flush_icache_range(region->vm_start, region->vm_end);
1453 region->vm_icache_flushed = true;
1456 up_write(&nommu_region_sem);
1458 kleave(" = %lx", result);
1462 up_write(&nommu_region_sem);
1464 if (region->vm_file)
1465 fput(region->vm_file);
1466 kmem_cache_free(vm_region_jar, region);
1469 kmem_cache_free(vm_area_cachep, vma);
1470 kleave(" = %d", ret);
1474 up_write(&nommu_region_sem);
1475 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1480 kmem_cache_free(vm_region_jar, region);
1481 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1482 " from process %d failed\n",
1487 error_getting_region:
1488 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1489 " from process %d failed\n",
1495 SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1496 unsigned long, prot, unsigned long, flags,
1497 unsigned long, fd, unsigned long, pgoff)
1499 struct file *file = NULL;
1500 unsigned long retval = -EBADF;
1502 audit_mmap_fd(fd, flags);
1503 if (!(flags & MAP_ANONYMOUS)) {
1509 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1511 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1519 #ifdef __ARCH_WANT_SYS_OLD_MMAP
1520 struct mmap_arg_struct {
1524 unsigned long flags;
1526 unsigned long offset;
1529 SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1531 struct mmap_arg_struct a;
1533 if (copy_from_user(&a, arg, sizeof(a)))
1535 if (a.offset & ~PAGE_MASK)
1538 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1539 a.offset >> PAGE_SHIFT);
1541 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1544 * split a vma into two pieces at address 'addr', a new vma is allocated either
1545 * for the first part or the tail.
1547 int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1548 unsigned long addr, int new_below)
1550 struct vm_area_struct *new;
1551 struct vm_region *region;
1552 unsigned long npages;
1556 /* we're only permitted to split anonymous regions (these should have
1557 * only a single usage on the region) */
1561 if (mm->map_count >= sysctl_max_map_count)
1564 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1568 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1570 kmem_cache_free(vm_region_jar, region);
1574 /* most fields are the same, copy all, and then fixup */
1576 *region = *vma->vm_region;
1577 new->vm_region = region;
1579 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1582 region->vm_top = region->vm_end = new->vm_end = addr;
1584 region->vm_start = new->vm_start = addr;
1585 region->vm_pgoff = new->vm_pgoff += npages;
1588 if (new->vm_ops && new->vm_ops->open)
1589 new->vm_ops->open(new);
1591 delete_vma_from_mm(vma);
1592 down_write(&nommu_region_sem);
1593 delete_nommu_region(vma->vm_region);
1595 vma->vm_region->vm_start = vma->vm_start = addr;
1596 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1598 vma->vm_region->vm_end = vma->vm_end = addr;
1599 vma->vm_region->vm_top = addr;
1601 add_nommu_region(vma->vm_region);
1602 add_nommu_region(new->vm_region);
1603 up_write(&nommu_region_sem);
1604 add_vma_to_mm(mm, vma);
1605 add_vma_to_mm(mm, new);
1610 * shrink a VMA by removing the specified chunk from either the beginning or
1613 static int shrink_vma(struct mm_struct *mm,
1614 struct vm_area_struct *vma,
1615 unsigned long from, unsigned long to)
1617 struct vm_region *region;
1621 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1623 delete_vma_from_mm(vma);
1624 if (from > vma->vm_start)
1628 add_vma_to_mm(mm, vma);
1630 /* cut the backing region down to size */
1631 region = vma->vm_region;
1632 BUG_ON(region->vm_usage != 1);
1634 down_write(&nommu_region_sem);
1635 delete_nommu_region(region);
1636 if (from > region->vm_start) {
1637 to = region->vm_top;
1638 region->vm_top = region->vm_end = from;
1640 region->vm_start = to;
1642 add_nommu_region(region);
1643 up_write(&nommu_region_sem);
1645 free_page_series(from, to);
1651 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1652 * VMA, though it need not cover the whole VMA
1654 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1656 struct vm_area_struct *vma;
1660 kenter(",%lx,%zx", start, len);
1662 len = PAGE_ALIGN(len);
1668 /* find the first potentially overlapping VMA */
1669 vma = find_vma(mm, start);
1671 static int limit = 0;
1674 "munmap of memory not mmapped by process %d"
1675 " (%s): 0x%lx-0x%lx\n",
1676 current->pid, current->comm,
1677 start, start + len - 1);
1683 /* we're allowed to split an anonymous VMA but not a file-backed one */
1686 if (start > vma->vm_start) {
1687 kleave(" = -EINVAL [miss]");
1690 if (end == vma->vm_end)
1691 goto erase_whole_vma;
1694 kleave(" = -EINVAL [split file]");
1697 /* the chunk must be a subset of the VMA found */
1698 if (start == vma->vm_start && end == vma->vm_end)
1699 goto erase_whole_vma;
1700 if (start < vma->vm_start || end > vma->vm_end) {
1701 kleave(" = -EINVAL [superset]");
1704 if (start & ~PAGE_MASK) {
1705 kleave(" = -EINVAL [unaligned start]");
1708 if (end != vma->vm_end && end & ~PAGE_MASK) {
1709 kleave(" = -EINVAL [unaligned split]");
1712 if (start != vma->vm_start && end != vma->vm_end) {
1713 ret = split_vma(mm, vma, start, 1);
1715 kleave(" = %d [split]", ret);
1719 return shrink_vma(mm, vma, start, end);
1723 delete_vma_from_mm(vma);
1724 delete_vma(mm, vma);
1728 EXPORT_SYMBOL(do_munmap);
1730 int vm_munmap(unsigned long addr, size_t len)
1732 struct mm_struct *mm = current->mm;
1735 down_write(&mm->mmap_sem);
1736 ret = do_munmap(mm, addr, len);
1737 up_write(&mm->mmap_sem);
1740 EXPORT_SYMBOL(vm_munmap);
1742 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1744 return vm_munmap(addr, len);
1748 * release all the mappings made in a process's VM space
1750 void exit_mmap(struct mm_struct *mm)
1752 struct vm_area_struct *vma;
1761 while ((vma = mm->mmap)) {
1762 mm->mmap = vma->vm_next;
1763 delete_vma_from_mm(vma);
1764 delete_vma(mm, vma);
1771 unsigned long vm_brk(unsigned long addr, unsigned long len)
1777 * expand (or shrink) an existing mapping, potentially moving it at the same
1778 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1780 * under NOMMU conditions, we only permit changing a mapping's size, and only
1781 * as long as it stays within the region allocated by do_mmap_private() and the
1782 * block is not shareable
1784 * MREMAP_FIXED is not supported under NOMMU conditions
1786 static unsigned long do_mremap(unsigned long addr,
1787 unsigned long old_len, unsigned long new_len,
1788 unsigned long flags, unsigned long new_addr)
1790 struct vm_area_struct *vma;
1792 /* insanity checks first */
1793 old_len = PAGE_ALIGN(old_len);
1794 new_len = PAGE_ALIGN(new_len);
1795 if (old_len == 0 || new_len == 0)
1796 return (unsigned long) -EINVAL;
1798 if (addr & ~PAGE_MASK)
1801 if (flags & MREMAP_FIXED && new_addr != addr)
1802 return (unsigned long) -EINVAL;
1804 vma = find_vma_exact(current->mm, addr, old_len);
1806 return (unsigned long) -EINVAL;
1808 if (vma->vm_end != vma->vm_start + old_len)
1809 return (unsigned long) -EFAULT;
1811 if (vma->vm_flags & VM_MAYSHARE)
1812 return (unsigned long) -EPERM;
1814 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1815 return (unsigned long) -ENOMEM;
1817 /* all checks complete - do it */
1818 vma->vm_end = vma->vm_start + new_len;
1819 return vma->vm_start;
1822 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1823 unsigned long, new_len, unsigned long, flags,
1824 unsigned long, new_addr)
1828 down_write(¤t->mm->mmap_sem);
1829 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1830 up_write(¤t->mm->mmap_sem);
1834 struct page *follow_page_mask(struct vm_area_struct *vma,
1835 unsigned long address, unsigned int flags,
1836 unsigned int *page_mask)
1842 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1843 unsigned long pfn, unsigned long size, pgprot_t prot)
1845 if (addr != (pfn << PAGE_SHIFT))
1848 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1851 EXPORT_SYMBOL(remap_pfn_range);
1853 int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1855 unsigned long pfn = start >> PAGE_SHIFT;
1856 unsigned long vm_len = vma->vm_end - vma->vm_start;
1858 pfn += vma->vm_pgoff;
1859 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1861 EXPORT_SYMBOL(vm_iomap_memory);
1863 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1864 unsigned long pgoff)
1866 unsigned int size = vma->vm_end - vma->vm_start;
1868 if (!(vma->vm_flags & VM_USERMAP))
1871 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1872 vma->vm_end = vma->vm_start + size;
1876 EXPORT_SYMBOL(remap_vmalloc_range);
1878 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1879 unsigned long len, unsigned long pgoff, unsigned long flags)
1884 void unmap_mapping_range(struct address_space *mapping,
1885 loff_t const holebegin, loff_t const holelen,
1889 EXPORT_SYMBOL(unmap_mapping_range);
1892 * Check that a process has enough memory to allocate a new virtual
1893 * mapping. 0 means there is enough memory for the allocation to
1894 * succeed and -ENOMEM implies there is not.
1896 * We currently support three overcommit policies, which are set via the
1897 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1899 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1900 * Additional code 2002 Jul 20 by Robert Love.
1902 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1904 * Note this is a helper function intended to be used by LSMs which
1905 * wish to use this logic.
1907 int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1909 unsigned long free, allowed, reserve;
1911 vm_acct_memory(pages);
1914 * Sometimes we want to use more memory than we have
1916 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1919 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1920 free = global_page_state(NR_FREE_PAGES);
1921 free += global_page_state(NR_FILE_PAGES);
1924 * shmem pages shouldn't be counted as free in this
1925 * case, they can't be purged, only swapped out, and
1926 * that won't affect the overall amount of available
1927 * memory in the system.
1929 free -= global_page_state(NR_SHMEM);
1931 free += get_nr_swap_pages();
1934 * Any slabs which are created with the
1935 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1936 * which are reclaimable, under pressure. The dentry
1937 * cache and most inode caches should fall into this
1939 free += global_page_state(NR_SLAB_RECLAIMABLE);
1942 * Leave reserved pages. The pages are not for anonymous pages.
1944 if (free <= totalreserve_pages)
1947 free -= totalreserve_pages;
1950 * Reserve some for root
1953 free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
1961 allowed = vm_commit_limit();
1963 * Reserve some 3% for root
1966 allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
1969 * Don't let a single process grow so big a user can't recover
1972 reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
1973 allowed -= min(mm->total_vm / 32, reserve);
1976 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1980 vm_unacct_memory(pages);
1985 int in_gate_area_no_mm(unsigned long addr)
1990 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1995 EXPORT_SYMBOL(filemap_fault);
1997 void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
2001 EXPORT_SYMBOL(filemap_map_pages);
2003 int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
2004 unsigned long size, pgoff_t pgoff)
2009 EXPORT_SYMBOL(generic_file_remap_pages);
2011 static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
2012 unsigned long addr, void *buf, int len, int write)
2014 struct vm_area_struct *vma;
2016 down_read(&mm->mmap_sem);
2018 /* the access must start within one of the target process's mappings */
2019 vma = find_vma(mm, addr);
2021 /* don't overrun this mapping */
2022 if (addr + len >= vma->vm_end)
2023 len = vma->vm_end - addr;
2025 /* only read or write mappings where it is permitted */
2026 if (write && vma->vm_flags & VM_MAYWRITE)
2027 copy_to_user_page(vma, NULL, addr,
2028 (void *) addr, buf, len);
2029 else if (!write && vma->vm_flags & VM_MAYREAD)
2030 copy_from_user_page(vma, NULL, addr,
2031 buf, (void *) addr, len);
2038 up_read(&mm->mmap_sem);
2044 * @access_remote_vm - access another process' address space
2045 * @mm: the mm_struct of the target address space
2046 * @addr: start address to access
2047 * @buf: source or destination buffer
2048 * @len: number of bytes to transfer
2049 * @write: whether the access is a write
2051 * The caller must hold a reference on @mm.
2053 int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2054 void *buf, int len, int write)
2056 return __access_remote_vm(NULL, mm, addr, buf, len, write);
2060 * Access another process' address space.
2061 * - source/target buffer must be kernel space
2063 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2065 struct mm_struct *mm;
2067 if (addr + len < addr)
2070 mm = get_task_mm(tsk);
2074 len = __access_remote_vm(tsk, mm, addr, buf, len, write);
2081 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
2082 * @inode: The inode to check
2083 * @size: The current filesize of the inode
2084 * @newsize: The proposed filesize of the inode
2086 * Check the shared mappings on an inode on behalf of a shrinking truncate to
2087 * make sure that that any outstanding VMAs aren't broken and then shrink the
2088 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
2089 * automatically grant mappings that are too large.
2091 int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
2094 struct vm_area_struct *vma;
2095 struct vm_region *region;
2097 size_t r_size, r_top;
2099 low = newsize >> PAGE_SHIFT;
2100 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2102 down_write(&nommu_region_sem);
2103 mutex_lock(&inode->i_mapping->i_mmap_mutex);
2105 /* search for VMAs that fall within the dead zone */
2106 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
2107 /* found one - only interested if it's shared out of the page
2109 if (vma->vm_flags & VM_SHARED) {
2110 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
2111 up_write(&nommu_region_sem);
2112 return -ETXTBSY; /* not quite true, but near enough */
2116 /* reduce any regions that overlap the dead zone - if in existence,
2117 * these will be pointed to by VMAs that don't overlap the dead zone
2119 * we don't check for any regions that start beyond the EOF as there
2122 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap,
2124 if (!(vma->vm_flags & VM_SHARED))
2127 region = vma->vm_region;
2128 r_size = region->vm_top - region->vm_start;
2129 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
2131 if (r_top > newsize) {
2132 region->vm_top -= r_top - newsize;
2133 if (region->vm_end > region->vm_top)
2134 region->vm_end = region->vm_top;
2138 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
2139 up_write(&nommu_region_sem);
2144 * Initialise sysctl_user_reserve_kbytes.
2146 * This is intended to prevent a user from starting a single memory hogging
2147 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
2150 * The default value is min(3% of free memory, 128MB)
2151 * 128MB is enough to recover with sshd/login, bash, and top/kill.
2153 static int __meminit init_user_reserve(void)
2155 unsigned long free_kbytes;
2157 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
2159 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
2162 module_init(init_user_reserve)
2165 * Initialise sysctl_admin_reserve_kbytes.
2167 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
2168 * to log in and kill a memory hogging process.
2170 * Systems with more than 256MB will reserve 8MB, enough to recover
2171 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
2172 * only reserve 3% of free pages by default.
2174 static int __meminit init_admin_reserve(void)
2176 unsigned long free_kbytes;
2178 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
2180 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
2183 module_init(init_admin_reserve)