net/can: add module alias to can protocol drivers
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / mm / nommu.c
blob2fd2ad5da98e5d82e751b76f4e6369c57f20e6db
1 /*
2 * linux/mm/nommu.c
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>
17 #include <linux/mm.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>
34 #include <asm/tlb.h>
35 #include <asm/tlbflush.h>
36 #include "internal.h"
38 static inline __attribute__((format(printf, 1, 2)))
39 void no_printk(const char *fmt, ...)
43 #if 0
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__)
50 #else
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__)
57 #endif
59 #include "internal.h"
61 void *high_memory;
62 struct page *mem_map;
63 unsigned long max_mapnr;
64 unsigned long num_physpages;
65 struct percpu_counter vm_committed_as;
66 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
67 int sysctl_overcommit_ratio = 50; /* default is 50% */
68 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
69 int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
70 int heap_stack_gap = 0;
72 /* amount of vm to protect from userspace access */
73 unsigned long mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
75 atomic_long_t mmap_pages_allocated;
77 EXPORT_SYMBOL(mem_map);
78 EXPORT_SYMBOL(num_physpages);
80 /* list of mapped, potentially shareable regions */
81 static struct kmem_cache *vm_region_jar;
82 struct rb_root nommu_region_tree = RB_ROOT;
83 DECLARE_RWSEM(nommu_region_sem);
85 struct vm_operations_struct generic_file_vm_ops = {
89 * Handle all mappings that got truncated by a "truncate()"
90 * system call.
92 * NOTE! We have to be ready to update the memory sharing
93 * between the file and the memory map for a potential last
94 * incomplete page. Ugly, but necessary.
96 int vmtruncate(struct inode *inode, loff_t offset)
98 struct address_space *mapping = inode->i_mapping;
99 unsigned long limit;
101 if (inode->i_size < offset)
102 goto do_expand;
103 i_size_write(inode, offset);
105 truncate_inode_pages(mapping, offset);
106 goto out_truncate;
108 do_expand:
109 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
110 if (limit != RLIM_INFINITY && offset > limit)
111 goto out_sig;
112 if (offset > inode->i_sb->s_maxbytes)
113 goto out;
114 i_size_write(inode, offset);
116 out_truncate:
117 if (inode->i_op->truncate)
118 inode->i_op->truncate(inode);
119 return 0;
120 out_sig:
121 send_sig(SIGXFSZ, current, 0);
122 out:
123 return -EFBIG;
126 EXPORT_SYMBOL(vmtruncate);
129 * Return the total memory allocated for this pointer, not
130 * just what the caller asked for.
132 * Doesn't have to be accurate, i.e. may have races.
134 unsigned int kobjsize(const void *objp)
136 struct page *page;
139 * If the object we have should not have ksize performed on it,
140 * return size of 0
142 if (!objp || !virt_addr_valid(objp))
143 return 0;
145 page = virt_to_head_page(objp);
148 * If the allocator sets PageSlab, we know the pointer came from
149 * kmalloc().
151 if (PageSlab(page))
152 return ksize(objp);
155 * If it's not a compound page, see if we have a matching VMA
156 * region. This test is intentionally done in reverse order,
157 * so if there's no VMA, we still fall through and hand back
158 * PAGE_SIZE for 0-order pages.
160 if (!PageCompound(page)) {
161 struct vm_area_struct *vma;
163 vma = find_vma(current->mm, (unsigned long)objp);
164 if (vma)
165 return vma->vm_end - vma->vm_start;
169 * The ksize() function is only guaranteed to work for pointers
170 * returned by kmalloc(). So handle arbitrary pointers here.
172 return PAGE_SIZE << compound_order(page);
175 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
176 unsigned long start, int len, int flags,
177 struct page **pages, struct vm_area_struct **vmas)
179 struct vm_area_struct *vma;
180 unsigned long vm_flags;
181 int i;
182 int write = !!(flags & GUP_FLAGS_WRITE);
183 int force = !!(flags & GUP_FLAGS_FORCE);
184 int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
186 /* calculate required read or write permissions.
187 * - if 'force' is set, we only require the "MAY" flags.
189 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
190 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
192 for (i = 0; i < len; i++) {
193 vma = find_vma(mm, start);
194 if (!vma)
195 goto finish_or_fault;
197 /* protect what we can, including chardevs */
198 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
199 (!ignore && !(vm_flags & vma->vm_flags)))
200 goto finish_or_fault;
202 if (pages) {
203 pages[i] = virt_to_page(start);
204 if (pages[i])
205 page_cache_get(pages[i]);
207 if (vmas)
208 vmas[i] = vma;
209 start += PAGE_SIZE;
212 return i;
214 finish_or_fault:
215 return i ? : -EFAULT;
220 * get a list of pages in an address range belonging to the specified process
221 * and indicate the VMA that covers each page
222 * - this is potentially dodgy as we may end incrementing the page count of a
223 * slab page or a secondary page from a compound page
224 * - don't permit access to VMAs that don't support it, such as I/O mappings
226 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
227 unsigned long start, int len, int write, int force,
228 struct page **pages, struct vm_area_struct **vmas)
230 int flags = 0;
232 if (write)
233 flags |= GUP_FLAGS_WRITE;
234 if (force)
235 flags |= GUP_FLAGS_FORCE;
237 return __get_user_pages(tsk, mm,
238 start, len, flags,
239 pages, vmas);
241 EXPORT_SYMBOL(get_user_pages);
243 DEFINE_RWLOCK(vmlist_lock);
244 struct vm_struct *vmlist;
246 void vfree(const void *addr)
248 kfree(addr);
250 EXPORT_SYMBOL(vfree);
252 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
255 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
256 * returns only a logical address.
258 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
260 EXPORT_SYMBOL(__vmalloc);
262 void *vmalloc_user(unsigned long size)
264 void *ret;
266 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
267 PAGE_KERNEL);
268 if (ret) {
269 struct vm_area_struct *vma;
271 down_write(&current->mm->mmap_sem);
272 vma = find_vma(current->mm, (unsigned long)ret);
273 if (vma)
274 vma->vm_flags |= VM_USERMAP;
275 up_write(&current->mm->mmap_sem);
278 return ret;
280 EXPORT_SYMBOL(vmalloc_user);
282 struct page *vmalloc_to_page(const void *addr)
284 return virt_to_page(addr);
286 EXPORT_SYMBOL(vmalloc_to_page);
288 unsigned long vmalloc_to_pfn(const void *addr)
290 return page_to_pfn(virt_to_page(addr));
292 EXPORT_SYMBOL(vmalloc_to_pfn);
294 long vread(char *buf, char *addr, unsigned long count)
296 memcpy(buf, addr, count);
297 return count;
300 long vwrite(char *buf, char *addr, unsigned long count)
302 /* Don't allow overflow */
303 if ((unsigned long) addr + count < count)
304 count = -(unsigned long) addr;
306 memcpy(addr, buf, count);
307 return(count);
311 * vmalloc - allocate virtually continguos memory
313 * @size: allocation size
315 * Allocate enough pages to cover @size from the page level
316 * allocator and map them into continguos kernel virtual space.
318 * For tight control over page level allocator and protection flags
319 * use __vmalloc() instead.
321 void *vmalloc(unsigned long size)
323 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
325 EXPORT_SYMBOL(vmalloc);
327 void *vmalloc_node(unsigned long size, int node)
329 return vmalloc(size);
331 EXPORT_SYMBOL(vmalloc_node);
333 #ifndef PAGE_KERNEL_EXEC
334 # define PAGE_KERNEL_EXEC PAGE_KERNEL
335 #endif
338 * vmalloc_exec - allocate virtually contiguous, executable memory
339 * @size: allocation size
341 * Kernel-internal function to allocate enough pages to cover @size
342 * the page level allocator and map them into contiguous and
343 * executable kernel virtual space.
345 * For tight control over page level allocator and protection flags
346 * use __vmalloc() instead.
349 void *vmalloc_exec(unsigned long size)
351 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
355 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
356 * @size: allocation size
358 * Allocate enough 32bit PA addressable pages to cover @size from the
359 * page level allocator and map them into continguos kernel virtual space.
361 void *vmalloc_32(unsigned long size)
363 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
365 EXPORT_SYMBOL(vmalloc_32);
368 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
369 * @size: allocation size
371 * The resulting memory area is 32bit addressable and zeroed so it can be
372 * mapped to userspace without leaking data.
374 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
375 * remap_vmalloc_range() are permissible.
377 void *vmalloc_32_user(unsigned long size)
380 * We'll have to sort out the ZONE_DMA bits for 64-bit,
381 * but for now this can simply use vmalloc_user() directly.
383 return vmalloc_user(size);
385 EXPORT_SYMBOL(vmalloc_32_user);
387 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
389 BUG();
390 return NULL;
392 EXPORT_SYMBOL(vmap);
394 void vunmap(const void *addr)
396 BUG();
398 EXPORT_SYMBOL(vunmap);
400 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
402 BUG();
403 return NULL;
405 EXPORT_SYMBOL(vm_map_ram);
407 void vm_unmap_ram(const void *mem, unsigned int count)
409 BUG();
411 EXPORT_SYMBOL(vm_unmap_ram);
413 void vm_unmap_aliases(void)
416 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
419 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
420 * have one.
422 void __attribute__((weak)) vmalloc_sync_all(void)
426 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
427 struct page *page)
429 return -EINVAL;
431 EXPORT_SYMBOL(vm_insert_page);
434 * sys_brk() for the most part doesn't need the global kernel
435 * lock, except when an application is doing something nasty
436 * like trying to un-brk an area that has already been mapped
437 * to a regular file. in this case, the unmapping will need
438 * to invoke file system routines that need the global lock.
440 SYSCALL_DEFINE1(brk, unsigned long, brk)
442 struct mm_struct *mm = current->mm;
444 if (brk < mm->start_brk || brk > mm->context.end_brk)
445 return mm->brk;
447 if (mm->brk == brk)
448 return mm->brk;
451 * Always allow shrinking brk
453 if (brk <= mm->brk) {
454 mm->brk = brk;
455 return brk;
459 * Ok, looks good - let it rip.
461 return mm->brk = brk;
465 * initialise the VMA and region record slabs
467 void __init mmap_init(void)
469 int ret;
471 ret = percpu_counter_init(&vm_committed_as, 0);
472 VM_BUG_ON(ret);
473 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
477 * validate the region tree
478 * - the caller must hold the region lock
480 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
481 static noinline void validate_nommu_regions(void)
483 struct vm_region *region, *last;
484 struct rb_node *p, *lastp;
486 lastp = rb_first(&nommu_region_tree);
487 if (!lastp)
488 return;
490 last = rb_entry(lastp, struct vm_region, vm_rb);
491 BUG_ON(unlikely(last->vm_end <= last->vm_start));
492 BUG_ON(unlikely(last->vm_top < last->vm_end));
494 while ((p = rb_next(lastp))) {
495 region = rb_entry(p, struct vm_region, vm_rb);
496 last = rb_entry(lastp, struct vm_region, vm_rb);
498 BUG_ON(unlikely(region->vm_end <= region->vm_start));
499 BUG_ON(unlikely(region->vm_top < region->vm_end));
500 BUG_ON(unlikely(region->vm_start < last->vm_top));
502 lastp = p;
505 #else
506 static void validate_nommu_regions(void)
509 #endif
512 * add a region into the global tree
514 static void add_nommu_region(struct vm_region *region)
516 struct vm_region *pregion;
517 struct rb_node **p, *parent;
519 validate_nommu_regions();
521 parent = NULL;
522 p = &nommu_region_tree.rb_node;
523 while (*p) {
524 parent = *p;
525 pregion = rb_entry(parent, struct vm_region, vm_rb);
526 if (region->vm_start < pregion->vm_start)
527 p = &(*p)->rb_left;
528 else if (region->vm_start > pregion->vm_start)
529 p = &(*p)->rb_right;
530 else if (pregion == region)
531 return;
532 else
533 BUG();
536 rb_link_node(&region->vm_rb, parent, p);
537 rb_insert_color(&region->vm_rb, &nommu_region_tree);
539 validate_nommu_regions();
543 * delete a region from the global tree
545 static void delete_nommu_region(struct vm_region *region)
547 BUG_ON(!nommu_region_tree.rb_node);
549 validate_nommu_regions();
550 rb_erase(&region->vm_rb, &nommu_region_tree);
551 validate_nommu_regions();
555 * free a contiguous series of pages
557 static void free_page_series(unsigned long from, unsigned long to)
559 for (; from < to; from += PAGE_SIZE) {
560 struct page *page = virt_to_page(from);
562 kdebug("- free %lx", from);
563 atomic_long_dec(&mmap_pages_allocated);
564 if (page_count(page) != 1)
565 kdebug("free page %p: refcount not one: %d",
566 page, page_count(page));
567 put_page(page);
572 * release a reference to a region
573 * - the caller must hold the region semaphore for writing, which this releases
574 * - the region may not have been added to the tree yet, in which case vm_top
575 * will equal vm_start
577 static void __put_nommu_region(struct vm_region *region)
578 __releases(nommu_region_sem)
580 kenter("%p{%d}", region, atomic_read(&region->vm_usage));
582 BUG_ON(!nommu_region_tree.rb_node);
584 if (atomic_dec_and_test(&region->vm_usage)) {
585 if (region->vm_top > region->vm_start)
586 delete_nommu_region(region);
587 up_write(&nommu_region_sem);
589 if (region->vm_file)
590 fput(region->vm_file);
592 /* IO memory and memory shared directly out of the pagecache
593 * from ramfs/tmpfs mustn't be released here */
594 if (region->vm_flags & VM_MAPPED_COPY) {
595 kdebug("free series");
596 free_page_series(region->vm_start, region->vm_top);
598 kmem_cache_free(vm_region_jar, region);
599 } else {
600 up_write(&nommu_region_sem);
605 * release a reference to a region
607 static void put_nommu_region(struct vm_region *region)
609 down_write(&nommu_region_sem);
610 __put_nommu_region(region);
614 * add a VMA into a process's mm_struct in the appropriate place in the list
615 * and tree and add to the address space's page tree also if not an anonymous
616 * page
617 * - should be called with mm->mmap_sem held writelocked
619 static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
621 struct vm_area_struct *pvma, **pp;
622 struct address_space *mapping;
623 struct rb_node **p, *parent;
625 kenter(",%p", vma);
627 BUG_ON(!vma->vm_region);
629 mm->map_count++;
630 vma->vm_mm = mm;
632 /* add the VMA to the mapping */
633 if (vma->vm_file) {
634 mapping = vma->vm_file->f_mapping;
636 flush_dcache_mmap_lock(mapping);
637 vma_prio_tree_insert(vma, &mapping->i_mmap);
638 flush_dcache_mmap_unlock(mapping);
641 /* add the VMA to the tree */
642 parent = NULL;
643 p = &mm->mm_rb.rb_node;
644 while (*p) {
645 parent = *p;
646 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
648 /* sort by: start addr, end addr, VMA struct addr in that order
649 * (the latter is necessary as we may get identical VMAs) */
650 if (vma->vm_start < pvma->vm_start)
651 p = &(*p)->rb_left;
652 else if (vma->vm_start > pvma->vm_start)
653 p = &(*p)->rb_right;
654 else if (vma->vm_end < pvma->vm_end)
655 p = &(*p)->rb_left;
656 else if (vma->vm_end > pvma->vm_end)
657 p = &(*p)->rb_right;
658 else if (vma < pvma)
659 p = &(*p)->rb_left;
660 else if (vma > pvma)
661 p = &(*p)->rb_right;
662 else
663 BUG();
666 rb_link_node(&vma->vm_rb, parent, p);
667 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
669 /* add VMA to the VMA list also */
670 for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
671 if (pvma->vm_start > vma->vm_start)
672 break;
673 if (pvma->vm_start < vma->vm_start)
674 continue;
675 if (pvma->vm_end < vma->vm_end)
676 break;
679 vma->vm_next = *pp;
680 *pp = vma;
684 * delete a VMA from its owning mm_struct and address space
686 static void delete_vma_from_mm(struct vm_area_struct *vma)
688 struct vm_area_struct **pp;
689 struct address_space *mapping;
690 struct mm_struct *mm = vma->vm_mm;
692 kenter("%p", vma);
694 mm->map_count--;
695 if (mm->mmap_cache == vma)
696 mm->mmap_cache = NULL;
698 /* remove the VMA from the mapping */
699 if (vma->vm_file) {
700 mapping = vma->vm_file->f_mapping;
702 flush_dcache_mmap_lock(mapping);
703 vma_prio_tree_remove(vma, &mapping->i_mmap);
704 flush_dcache_mmap_unlock(mapping);
707 /* remove from the MM's tree and list */
708 rb_erase(&vma->vm_rb, &mm->mm_rb);
709 for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
710 if (*pp == vma) {
711 *pp = vma->vm_next;
712 break;
716 vma->vm_mm = NULL;
720 * destroy a VMA record
722 static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
724 kenter("%p", vma);
725 if (vma->vm_ops && vma->vm_ops->close)
726 vma->vm_ops->close(vma);
727 if (vma->vm_file) {
728 fput(vma->vm_file);
729 if (vma->vm_flags & VM_EXECUTABLE)
730 removed_exe_file_vma(mm);
732 put_nommu_region(vma->vm_region);
733 kmem_cache_free(vm_area_cachep, vma);
737 * look up the first VMA in which addr resides, NULL if none
738 * - should be called with mm->mmap_sem at least held readlocked
740 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
742 struct vm_area_struct *vma;
743 struct rb_node *n = mm->mm_rb.rb_node;
745 /* check the cache first */
746 vma = mm->mmap_cache;
747 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
748 return vma;
750 /* trawl the tree (there may be multiple mappings in which addr
751 * resides) */
752 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
753 vma = rb_entry(n, struct vm_area_struct, vm_rb);
754 if (vma->vm_start > addr)
755 return NULL;
756 if (vma->vm_end > addr) {
757 mm->mmap_cache = vma;
758 return vma;
762 return NULL;
764 EXPORT_SYMBOL(find_vma);
767 * find a VMA
768 * - we don't extend stack VMAs under NOMMU conditions
770 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
772 return find_vma(mm, addr);
776 * expand a stack to a given address
777 * - not supported under NOMMU conditions
779 int expand_stack(struct vm_area_struct *vma, unsigned long address)
781 return -ENOMEM;
785 * look up the first VMA exactly that exactly matches addr
786 * - should be called with mm->mmap_sem at least held readlocked
788 static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
789 unsigned long addr,
790 unsigned long len)
792 struct vm_area_struct *vma;
793 struct rb_node *n = mm->mm_rb.rb_node;
794 unsigned long end = addr + len;
796 /* check the cache first */
797 vma = mm->mmap_cache;
798 if (vma && vma->vm_start == addr && vma->vm_end == end)
799 return vma;
801 /* trawl the tree (there may be multiple mappings in which addr
802 * resides) */
803 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
804 vma = rb_entry(n, struct vm_area_struct, vm_rb);
805 if (vma->vm_start < addr)
806 continue;
807 if (vma->vm_start > addr)
808 return NULL;
809 if (vma->vm_end == end) {
810 mm->mmap_cache = vma;
811 return vma;
815 return NULL;
819 * determine whether a mapping should be permitted and, if so, what sort of
820 * mapping we're capable of supporting
822 static int validate_mmap_request(struct file *file,
823 unsigned long addr,
824 unsigned long len,
825 unsigned long prot,
826 unsigned long flags,
827 unsigned long pgoff,
828 unsigned long *_capabilities)
830 unsigned long capabilities, rlen;
831 unsigned long reqprot = prot;
832 int ret;
834 /* do the simple checks first */
835 if (flags & MAP_FIXED || addr) {
836 printk(KERN_DEBUG
837 "%d: Can't do fixed-address/overlay mmap of RAM\n",
838 current->pid);
839 return -EINVAL;
842 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
843 (flags & MAP_TYPE) != MAP_SHARED)
844 return -EINVAL;
846 if (!len)
847 return -EINVAL;
849 /* Careful about overflows.. */
850 rlen = PAGE_ALIGN(len);
851 if (!rlen || rlen > TASK_SIZE)
852 return -ENOMEM;
854 /* offset overflow? */
855 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
856 return -EOVERFLOW;
858 if (file) {
859 /* validate file mapping requests */
860 struct address_space *mapping;
862 /* files must support mmap */
863 if (!file->f_op || !file->f_op->mmap)
864 return -ENODEV;
866 /* work out if what we've got could possibly be shared
867 * - we support chardevs that provide their own "memory"
868 * - we support files/blockdevs that are memory backed
870 mapping = file->f_mapping;
871 if (!mapping)
872 mapping = file->f_path.dentry->d_inode->i_mapping;
874 capabilities = 0;
875 if (mapping && mapping->backing_dev_info)
876 capabilities = mapping->backing_dev_info->capabilities;
878 if (!capabilities) {
879 /* no explicit capabilities set, so assume some
880 * defaults */
881 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
882 case S_IFREG:
883 case S_IFBLK:
884 capabilities = BDI_CAP_MAP_COPY;
885 break;
887 case S_IFCHR:
888 capabilities =
889 BDI_CAP_MAP_DIRECT |
890 BDI_CAP_READ_MAP |
891 BDI_CAP_WRITE_MAP;
892 break;
894 default:
895 return -EINVAL;
899 /* eliminate any capabilities that we can't support on this
900 * device */
901 if (!file->f_op->get_unmapped_area)
902 capabilities &= ~BDI_CAP_MAP_DIRECT;
903 if (!file->f_op->read)
904 capabilities &= ~BDI_CAP_MAP_COPY;
906 if (flags & MAP_SHARED) {
907 /* do checks for writing, appending and locking */
908 if ((prot & PROT_WRITE) &&
909 !(file->f_mode & FMODE_WRITE))
910 return -EACCES;
912 if (IS_APPEND(file->f_path.dentry->d_inode) &&
913 (file->f_mode & FMODE_WRITE))
914 return -EACCES;
916 if (locks_verify_locked(file->f_path.dentry->d_inode))
917 return -EAGAIN;
919 if (!(capabilities & BDI_CAP_MAP_DIRECT))
920 return -ENODEV;
922 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
923 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
924 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
926 printk("MAP_SHARED not completely supported on !MMU\n");
927 return -EINVAL;
930 /* we mustn't privatise shared mappings */
931 capabilities &= ~BDI_CAP_MAP_COPY;
933 else {
934 /* we're going to read the file into private memory we
935 * allocate */
936 if (!(capabilities & BDI_CAP_MAP_COPY))
937 return -ENODEV;
939 /* we don't permit a private writable mapping to be
940 * shared with the backing device */
941 if (prot & PROT_WRITE)
942 capabilities &= ~BDI_CAP_MAP_DIRECT;
945 /* handle executable mappings and implied executable
946 * mappings */
947 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
948 if (prot & PROT_EXEC)
949 return -EPERM;
951 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
952 /* handle implication of PROT_EXEC by PROT_READ */
953 if (current->personality & READ_IMPLIES_EXEC) {
954 if (capabilities & BDI_CAP_EXEC_MAP)
955 prot |= PROT_EXEC;
958 else if ((prot & PROT_READ) &&
959 (prot & PROT_EXEC) &&
960 !(capabilities & BDI_CAP_EXEC_MAP)
962 /* backing file is not executable, try to copy */
963 capabilities &= ~BDI_CAP_MAP_DIRECT;
966 else {
967 /* anonymous mappings are always memory backed and can be
968 * privately mapped
970 capabilities = BDI_CAP_MAP_COPY;
972 /* handle PROT_EXEC implication by PROT_READ */
973 if ((prot & PROT_READ) &&
974 (current->personality & READ_IMPLIES_EXEC))
975 prot |= PROT_EXEC;
978 /* allow the security API to have its say */
979 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
980 if (ret < 0)
981 return ret;
983 /* looks okay */
984 *_capabilities = capabilities;
985 return 0;
989 * we've determined that we can make the mapping, now translate what we
990 * now know into VMA flags
992 static unsigned long determine_vm_flags(struct file *file,
993 unsigned long prot,
994 unsigned long flags,
995 unsigned long capabilities)
997 unsigned long vm_flags;
999 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
1000 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1001 /* vm_flags |= mm->def_flags; */
1003 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1004 /* attempt to share read-only copies of mapped file chunks */
1005 if (file && !(prot & PROT_WRITE))
1006 vm_flags |= VM_MAYSHARE;
1008 else {
1009 /* overlay a shareable mapping on the backing device or inode
1010 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1011 * romfs/cramfs */
1012 if (flags & MAP_SHARED)
1013 vm_flags |= VM_MAYSHARE | VM_SHARED;
1014 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1015 vm_flags |= VM_MAYSHARE;
1018 /* refuse to let anyone share private mappings with this process if
1019 * it's being traced - otherwise breakpoints set in it may interfere
1020 * with another untraced process
1022 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
1023 vm_flags &= ~VM_MAYSHARE;
1025 return vm_flags;
1029 * set up a shared mapping on a file (the driver or filesystem provides and
1030 * pins the storage)
1032 static int do_mmap_shared_file(struct vm_area_struct *vma)
1034 int ret;
1036 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1037 if (ret == 0) {
1038 vma->vm_region->vm_top = vma->vm_region->vm_end;
1039 return ret;
1041 if (ret != -ENOSYS)
1042 return ret;
1044 /* getting an ENOSYS error indicates that direct mmap isn't
1045 * possible (as opposed to tried but failed) so we'll fall
1046 * through to making a private copy of the data and mapping
1047 * that if we can */
1048 return -ENODEV;
1052 * set up a private mapping or an anonymous shared mapping
1054 static int do_mmap_private(struct vm_area_struct *vma,
1055 struct vm_region *region,
1056 unsigned long len)
1058 struct page *pages;
1059 unsigned long total, point, n, rlen;
1060 void *base;
1061 int ret, order;
1063 /* invoke the file's mapping function so that it can keep track of
1064 * shared mappings on devices or memory
1065 * - VM_MAYSHARE will be set if it may attempt to share
1067 if (vma->vm_file) {
1068 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1069 if (ret == 0) {
1070 /* shouldn't return success if we're not sharing */
1071 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1072 vma->vm_region->vm_top = vma->vm_region->vm_end;
1073 return ret;
1075 if (ret != -ENOSYS)
1076 return ret;
1078 /* getting an ENOSYS error indicates that direct mmap isn't
1079 * possible (as opposed to tried but failed) so we'll try to
1080 * make a private copy of the data and map that instead */
1083 rlen = PAGE_ALIGN(len);
1085 /* allocate some memory to hold the mapping
1086 * - note that this may not return a page-aligned address if the object
1087 * we're allocating is smaller than a page
1089 order = get_order(rlen);
1090 kdebug("alloc order %d for %lx", order, len);
1092 pages = alloc_pages(GFP_KERNEL, order);
1093 if (!pages)
1094 goto enomem;
1096 total = 1 << order;
1097 atomic_long_add(total, &mmap_pages_allocated);
1099 point = rlen >> PAGE_SHIFT;
1101 /* we allocated a power-of-2 sized page set, so we may want to trim off
1102 * the excess */
1103 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1104 while (total > point) {
1105 order = ilog2(total - point);
1106 n = 1 << order;
1107 kdebug("shave %lu/%lu @%lu", n, total - point, total);
1108 atomic_long_sub(n, &mmap_pages_allocated);
1109 total -= n;
1110 set_page_refcounted(pages + total);
1111 __free_pages(pages + total, order);
1115 for (point = 1; point < total; point++)
1116 set_page_refcounted(&pages[point]);
1118 base = page_address(pages);
1119 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1120 region->vm_start = (unsigned long) base;
1121 region->vm_end = region->vm_start + rlen;
1122 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1124 vma->vm_start = region->vm_start;
1125 vma->vm_end = region->vm_start + len;
1127 if (vma->vm_file) {
1128 /* read the contents of a file into the copy */
1129 mm_segment_t old_fs;
1130 loff_t fpos;
1132 fpos = vma->vm_pgoff;
1133 fpos <<= PAGE_SHIFT;
1135 old_fs = get_fs();
1136 set_fs(KERNEL_DS);
1137 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
1138 set_fs(old_fs);
1140 if (ret < 0)
1141 goto error_free;
1143 /* clear the last little bit */
1144 if (ret < rlen)
1145 memset(base + ret, 0, rlen - ret);
1147 } else {
1148 /* if it's an anonymous mapping, then just clear it */
1149 memset(base, 0, rlen);
1152 return 0;
1154 error_free:
1155 free_page_series(region->vm_start, region->vm_end);
1156 region->vm_start = vma->vm_start = 0;
1157 region->vm_end = vma->vm_end = 0;
1158 region->vm_top = 0;
1159 return ret;
1161 enomem:
1162 printk("Allocation of length %lu from process %d (%s) failed\n",
1163 len, current->pid, current->comm);
1164 show_free_areas();
1165 return -ENOMEM;
1169 * handle mapping creation for uClinux
1171 unsigned long do_mmap_pgoff(struct file *file,
1172 unsigned long addr,
1173 unsigned long len,
1174 unsigned long prot,
1175 unsigned long flags,
1176 unsigned long pgoff)
1178 struct vm_area_struct *vma;
1179 struct vm_region *region;
1180 struct rb_node *rb;
1181 unsigned long capabilities, vm_flags, result;
1182 int ret;
1184 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1186 if (!(flags & MAP_FIXED))
1187 addr = round_hint_to_min(addr);
1189 /* decide whether we should attempt the mapping, and if so what sort of
1190 * mapping */
1191 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1192 &capabilities);
1193 if (ret < 0) {
1194 kleave(" = %d [val]", ret);
1195 return ret;
1198 /* we've determined that we can make the mapping, now translate what we
1199 * now know into VMA flags */
1200 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1202 /* we're going to need to record the mapping */
1203 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1204 if (!region)
1205 goto error_getting_region;
1207 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1208 if (!vma)
1209 goto error_getting_vma;
1211 atomic_set(&region->vm_usage, 1);
1212 region->vm_flags = vm_flags;
1213 region->vm_pgoff = pgoff;
1215 INIT_LIST_HEAD(&vma->anon_vma_node);
1216 vma->vm_flags = vm_flags;
1217 vma->vm_pgoff = pgoff;
1219 if (file) {
1220 region->vm_file = file;
1221 get_file(file);
1222 vma->vm_file = file;
1223 get_file(file);
1224 if (vm_flags & VM_EXECUTABLE) {
1225 added_exe_file_vma(current->mm);
1226 vma->vm_mm = current->mm;
1230 down_write(&nommu_region_sem);
1232 /* if we want to share, we need to check for regions created by other
1233 * mmap() calls that overlap with our proposed mapping
1234 * - we can only share with a superset match on most regular files
1235 * - shared mappings on character devices and memory backed files are
1236 * permitted to overlap inexactly as far as we are concerned for in
1237 * these cases, sharing is handled in the driver or filesystem rather
1238 * than here
1240 if (vm_flags & VM_MAYSHARE) {
1241 struct vm_region *pregion;
1242 unsigned long pglen, rpglen, pgend, rpgend, start;
1244 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1245 pgend = pgoff + pglen;
1247 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1248 pregion = rb_entry(rb, struct vm_region, vm_rb);
1250 if (!(pregion->vm_flags & VM_MAYSHARE))
1251 continue;
1253 /* search for overlapping mappings on the same file */
1254 if (pregion->vm_file->f_path.dentry->d_inode !=
1255 file->f_path.dentry->d_inode)
1256 continue;
1258 if (pregion->vm_pgoff >= pgend)
1259 continue;
1261 rpglen = pregion->vm_end - pregion->vm_start;
1262 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1263 rpgend = pregion->vm_pgoff + rpglen;
1264 if (pgoff >= rpgend)
1265 continue;
1267 /* handle inexactly overlapping matches between
1268 * mappings */
1269 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1270 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1271 /* new mapping is not a subset of the region */
1272 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1273 goto sharing_violation;
1274 continue;
1277 /* we've found a region we can share */
1278 atomic_inc(&pregion->vm_usage);
1279 vma->vm_region = pregion;
1280 start = pregion->vm_start;
1281 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1282 vma->vm_start = start;
1283 vma->vm_end = start + len;
1285 if (pregion->vm_flags & VM_MAPPED_COPY) {
1286 kdebug("share copy");
1287 vma->vm_flags |= VM_MAPPED_COPY;
1288 } else {
1289 kdebug("share mmap");
1290 ret = do_mmap_shared_file(vma);
1291 if (ret < 0) {
1292 vma->vm_region = NULL;
1293 vma->vm_start = 0;
1294 vma->vm_end = 0;
1295 atomic_dec(&pregion->vm_usage);
1296 pregion = NULL;
1297 goto error_just_free;
1300 fput(region->vm_file);
1301 kmem_cache_free(vm_region_jar, region);
1302 region = pregion;
1303 result = start;
1304 goto share;
1307 /* obtain the address at which to make a shared mapping
1308 * - this is the hook for quasi-memory character devices to
1309 * tell us the location of a shared mapping
1311 if (file && file->f_op->get_unmapped_area) {
1312 addr = file->f_op->get_unmapped_area(file, addr, len,
1313 pgoff, flags);
1314 if (IS_ERR((void *) addr)) {
1315 ret = addr;
1316 if (ret != (unsigned long) -ENOSYS)
1317 goto error_just_free;
1319 /* the driver refused to tell us where to site
1320 * the mapping so we'll have to attempt to copy
1321 * it */
1322 ret = (unsigned long) -ENODEV;
1323 if (!(capabilities & BDI_CAP_MAP_COPY))
1324 goto error_just_free;
1326 capabilities &= ~BDI_CAP_MAP_DIRECT;
1327 } else {
1328 vma->vm_start = region->vm_start = addr;
1329 vma->vm_end = region->vm_end = addr + len;
1334 vma->vm_region = region;
1336 /* set up the mapping */
1337 if (file && vma->vm_flags & VM_SHARED)
1338 ret = do_mmap_shared_file(vma);
1339 else
1340 ret = do_mmap_private(vma, region, len);
1341 if (ret < 0)
1342 goto error_put_region;
1344 add_nommu_region(region);
1346 /* okay... we have a mapping; now we have to register it */
1347 result = vma->vm_start;
1349 current->mm->total_vm += len >> PAGE_SHIFT;
1351 share:
1352 add_vma_to_mm(current->mm, vma);
1354 up_write(&nommu_region_sem);
1356 if (prot & PROT_EXEC)
1357 flush_icache_range(result, result + len);
1359 kleave(" = %lx", result);
1360 return result;
1362 error_put_region:
1363 __put_nommu_region(region);
1364 if (vma) {
1365 if (vma->vm_file) {
1366 fput(vma->vm_file);
1367 if (vma->vm_flags & VM_EXECUTABLE)
1368 removed_exe_file_vma(vma->vm_mm);
1370 kmem_cache_free(vm_area_cachep, vma);
1372 kleave(" = %d [pr]", ret);
1373 return ret;
1375 error_just_free:
1376 up_write(&nommu_region_sem);
1377 error:
1378 fput(region->vm_file);
1379 kmem_cache_free(vm_region_jar, region);
1380 fput(vma->vm_file);
1381 if (vma->vm_flags & VM_EXECUTABLE)
1382 removed_exe_file_vma(vma->vm_mm);
1383 kmem_cache_free(vm_area_cachep, vma);
1384 kleave(" = %d", ret);
1385 return ret;
1387 sharing_violation:
1388 up_write(&nommu_region_sem);
1389 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1390 ret = -EINVAL;
1391 goto error;
1393 error_getting_vma:
1394 kmem_cache_free(vm_region_jar, region);
1395 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1396 " from process %d failed\n",
1397 len, current->pid);
1398 show_free_areas();
1399 return -ENOMEM;
1401 error_getting_region:
1402 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1403 " from process %d failed\n",
1404 len, current->pid);
1405 show_free_areas();
1406 return -ENOMEM;
1408 EXPORT_SYMBOL(do_mmap_pgoff);
1411 * split a vma into two pieces at address 'addr', a new vma is allocated either
1412 * for the first part or the tail.
1414 int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1415 unsigned long addr, int new_below)
1417 struct vm_area_struct *new;
1418 struct vm_region *region;
1419 unsigned long npages;
1421 kenter("");
1423 /* we're only permitted to split anonymous regions that have a single
1424 * owner */
1425 if (vma->vm_file ||
1426 atomic_read(&vma->vm_region->vm_usage) != 1)
1427 return -ENOMEM;
1429 if (mm->map_count >= sysctl_max_map_count)
1430 return -ENOMEM;
1432 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1433 if (!region)
1434 return -ENOMEM;
1436 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1437 if (!new) {
1438 kmem_cache_free(vm_region_jar, region);
1439 return -ENOMEM;
1442 /* most fields are the same, copy all, and then fixup */
1443 *new = *vma;
1444 *region = *vma->vm_region;
1445 new->vm_region = region;
1447 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1449 if (new_below) {
1450 region->vm_top = region->vm_end = new->vm_end = addr;
1451 } else {
1452 region->vm_start = new->vm_start = addr;
1453 region->vm_pgoff = new->vm_pgoff += npages;
1456 if (new->vm_ops && new->vm_ops->open)
1457 new->vm_ops->open(new);
1459 delete_vma_from_mm(vma);
1460 down_write(&nommu_region_sem);
1461 delete_nommu_region(vma->vm_region);
1462 if (new_below) {
1463 vma->vm_region->vm_start = vma->vm_start = addr;
1464 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1465 } else {
1466 vma->vm_region->vm_end = vma->vm_end = addr;
1467 vma->vm_region->vm_top = addr;
1469 add_nommu_region(vma->vm_region);
1470 add_nommu_region(new->vm_region);
1471 up_write(&nommu_region_sem);
1472 add_vma_to_mm(mm, vma);
1473 add_vma_to_mm(mm, new);
1474 return 0;
1478 * shrink a VMA by removing the specified chunk from either the beginning or
1479 * the end
1481 static int shrink_vma(struct mm_struct *mm,
1482 struct vm_area_struct *vma,
1483 unsigned long from, unsigned long to)
1485 struct vm_region *region;
1487 kenter("");
1489 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1490 * and list */
1491 delete_vma_from_mm(vma);
1492 if (from > vma->vm_start)
1493 vma->vm_end = from;
1494 else
1495 vma->vm_start = to;
1496 add_vma_to_mm(mm, vma);
1498 /* cut the backing region down to size */
1499 region = vma->vm_region;
1500 BUG_ON(atomic_read(&region->vm_usage) != 1);
1502 down_write(&nommu_region_sem);
1503 delete_nommu_region(region);
1504 if (from > region->vm_start) {
1505 to = region->vm_top;
1506 region->vm_top = region->vm_end = from;
1507 } else {
1508 region->vm_start = to;
1510 add_nommu_region(region);
1511 up_write(&nommu_region_sem);
1513 free_page_series(from, to);
1514 return 0;
1518 * release a mapping
1519 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1520 * VMA, though it need not cover the whole VMA
1522 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1524 struct vm_area_struct *vma;
1525 struct rb_node *rb;
1526 unsigned long end = start + len;
1527 int ret;
1529 kenter(",%lx,%zx", start, len);
1531 if (len == 0)
1532 return -EINVAL;
1534 /* find the first potentially overlapping VMA */
1535 vma = find_vma(mm, start);
1536 if (!vma) {
1537 static int limit = 0;
1538 if (limit < 5) {
1539 printk(KERN_WARNING
1540 "munmap of memory not mmapped by process %d"
1541 " (%s): 0x%lx-0x%lx\n",
1542 current->pid, current->comm,
1543 start, start + len - 1);
1544 limit++;
1546 return -EINVAL;
1549 /* we're allowed to split an anonymous VMA but not a file-backed one */
1550 if (vma->vm_file) {
1551 do {
1552 if (start > vma->vm_start) {
1553 kleave(" = -EINVAL [miss]");
1554 return -EINVAL;
1556 if (end == vma->vm_end)
1557 goto erase_whole_vma;
1558 rb = rb_next(&vma->vm_rb);
1559 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1560 } while (rb);
1561 kleave(" = -EINVAL [split file]");
1562 return -EINVAL;
1563 } else {
1564 /* the chunk must be a subset of the VMA found */
1565 if (start == vma->vm_start && end == vma->vm_end)
1566 goto erase_whole_vma;
1567 if (start < vma->vm_start || end > vma->vm_end) {
1568 kleave(" = -EINVAL [superset]");
1569 return -EINVAL;
1571 if (start & ~PAGE_MASK) {
1572 kleave(" = -EINVAL [unaligned start]");
1573 return -EINVAL;
1575 if (end != vma->vm_end && end & ~PAGE_MASK) {
1576 kleave(" = -EINVAL [unaligned split]");
1577 return -EINVAL;
1579 if (start != vma->vm_start && end != vma->vm_end) {
1580 ret = split_vma(mm, vma, start, 1);
1581 if (ret < 0) {
1582 kleave(" = %d [split]", ret);
1583 return ret;
1586 return shrink_vma(mm, vma, start, end);
1589 erase_whole_vma:
1590 delete_vma_from_mm(vma);
1591 delete_vma(mm, vma);
1592 kleave(" = 0");
1593 return 0;
1595 EXPORT_SYMBOL(do_munmap);
1597 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1599 int ret;
1600 struct mm_struct *mm = current->mm;
1602 down_write(&mm->mmap_sem);
1603 ret = do_munmap(mm, addr, len);
1604 up_write(&mm->mmap_sem);
1605 return ret;
1609 * release all the mappings made in a process's VM space
1611 void exit_mmap(struct mm_struct *mm)
1613 struct vm_area_struct *vma;
1615 if (!mm)
1616 return;
1618 kenter("");
1620 mm->total_vm = 0;
1622 while ((vma = mm->mmap)) {
1623 mm->mmap = vma->vm_next;
1624 delete_vma_from_mm(vma);
1625 delete_vma(mm, vma);
1628 kleave("");
1631 unsigned long do_brk(unsigned long addr, unsigned long len)
1633 return -ENOMEM;
1637 * expand (or shrink) an existing mapping, potentially moving it at the same
1638 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1640 * under NOMMU conditions, we only permit changing a mapping's size, and only
1641 * as long as it stays within the region allocated by do_mmap_private() and the
1642 * block is not shareable
1644 * MREMAP_FIXED is not supported under NOMMU conditions
1646 unsigned long do_mremap(unsigned long addr,
1647 unsigned long old_len, unsigned long new_len,
1648 unsigned long flags, unsigned long new_addr)
1650 struct vm_area_struct *vma;
1652 /* insanity checks first */
1653 if (old_len == 0 || new_len == 0)
1654 return (unsigned long) -EINVAL;
1656 if (addr & ~PAGE_MASK)
1657 return -EINVAL;
1659 if (flags & MREMAP_FIXED && new_addr != addr)
1660 return (unsigned long) -EINVAL;
1662 vma = find_vma_exact(current->mm, addr, old_len);
1663 if (!vma)
1664 return (unsigned long) -EINVAL;
1666 if (vma->vm_end != vma->vm_start + old_len)
1667 return (unsigned long) -EFAULT;
1669 if (vma->vm_flags & VM_MAYSHARE)
1670 return (unsigned long) -EPERM;
1672 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1673 return (unsigned long) -ENOMEM;
1675 /* all checks complete - do it */
1676 vma->vm_end = vma->vm_start + new_len;
1677 return vma->vm_start;
1679 EXPORT_SYMBOL(do_mremap);
1681 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1682 unsigned long, new_len, unsigned long, flags,
1683 unsigned long, new_addr)
1685 unsigned long ret;
1687 down_write(&current->mm->mmap_sem);
1688 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1689 up_write(&current->mm->mmap_sem);
1690 return ret;
1693 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1694 unsigned int foll_flags)
1696 return NULL;
1699 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1700 unsigned long to, unsigned long size, pgprot_t prot)
1702 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1703 return 0;
1705 EXPORT_SYMBOL(remap_pfn_range);
1707 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1708 unsigned long pgoff)
1710 unsigned int size = vma->vm_end - vma->vm_start;
1712 if (!(vma->vm_flags & VM_USERMAP))
1713 return -EINVAL;
1715 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1716 vma->vm_end = vma->vm_start + size;
1718 return 0;
1720 EXPORT_SYMBOL(remap_vmalloc_range);
1722 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1726 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1727 unsigned long len, unsigned long pgoff, unsigned long flags)
1729 return -ENOMEM;
1732 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1736 void unmap_mapping_range(struct address_space *mapping,
1737 loff_t const holebegin, loff_t const holelen,
1738 int even_cows)
1741 EXPORT_SYMBOL(unmap_mapping_range);
1744 * ask for an unmapped area at which to create a mapping on a file
1746 unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1747 unsigned long len, unsigned long pgoff,
1748 unsigned long flags)
1750 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1751 unsigned long, unsigned long);
1753 get_area = current->mm->get_unmapped_area;
1754 if (file && file->f_op && file->f_op->get_unmapped_area)
1755 get_area = file->f_op->get_unmapped_area;
1757 if (!get_area)
1758 return -ENOSYS;
1760 return get_area(file, addr, len, pgoff, flags);
1762 EXPORT_SYMBOL(get_unmapped_area);
1765 * Check that a process has enough memory to allocate a new virtual
1766 * mapping. 0 means there is enough memory for the allocation to
1767 * succeed and -ENOMEM implies there is not.
1769 * We currently support three overcommit policies, which are set via the
1770 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1772 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1773 * Additional code 2002 Jul 20 by Robert Love.
1775 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1777 * Note this is a helper function intended to be used by LSMs which
1778 * wish to use this logic.
1780 int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1782 unsigned long free, allowed;
1784 vm_acct_memory(pages);
1787 * Sometimes we want to use more memory than we have
1789 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1790 return 0;
1792 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1793 unsigned long n;
1795 free = global_page_state(NR_FILE_PAGES);
1796 free += nr_swap_pages;
1799 * Any slabs which are created with the
1800 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1801 * which are reclaimable, under pressure. The dentry
1802 * cache and most inode caches should fall into this
1804 free += global_page_state(NR_SLAB_RECLAIMABLE);
1807 * Leave the last 3% for root
1809 if (!cap_sys_admin)
1810 free -= free / 32;
1812 if (free > pages)
1813 return 0;
1816 * nr_free_pages() is very expensive on large systems,
1817 * only call if we're about to fail.
1819 n = nr_free_pages();
1822 * Leave reserved pages. The pages are not for anonymous pages.
1824 if (n <= totalreserve_pages)
1825 goto error;
1826 else
1827 n -= totalreserve_pages;
1830 * Leave the last 3% for root
1832 if (!cap_sys_admin)
1833 n -= n / 32;
1834 free += n;
1836 if (free > pages)
1837 return 0;
1839 goto error;
1842 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1844 * Leave the last 3% for root
1846 if (!cap_sys_admin)
1847 allowed -= allowed / 32;
1848 allowed += total_swap_pages;
1850 /* Don't let a single process grow too big:
1851 leave 3% of the size of this process for other processes */
1852 if (mm)
1853 allowed -= mm->total_vm / 32;
1855 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1856 return 0;
1858 error:
1859 vm_unacct_memory(pages);
1861 return -ENOMEM;
1864 int in_gate_area_no_task(unsigned long addr)
1866 return 0;
1869 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1871 BUG();
1872 return 0;
1874 EXPORT_SYMBOL(filemap_fault);
1877 * Access another process' address space.
1878 * - source/target buffer must be kernel space
1880 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1882 struct vm_area_struct *vma;
1883 struct mm_struct *mm;
1885 if (addr + len < addr)
1886 return 0;
1888 mm = get_task_mm(tsk);
1889 if (!mm)
1890 return 0;
1892 down_read(&mm->mmap_sem);
1894 /* the access must start within one of the target process's mappings */
1895 vma = find_vma(mm, addr);
1896 if (vma) {
1897 /* don't overrun this mapping */
1898 if (addr + len >= vma->vm_end)
1899 len = vma->vm_end - addr;
1901 /* only read or write mappings where it is permitted */
1902 if (write && vma->vm_flags & VM_MAYWRITE)
1903 len -= copy_to_user((void *) addr, buf, len);
1904 else if (!write && vma->vm_flags & VM_MAYREAD)
1905 len -= copy_from_user(buf, (void *) addr, len);
1906 else
1907 len = 0;
1908 } else {
1909 len = 0;
1912 up_read(&mm->mmap_sem);
1913 mmput(mm);
1914 return len;