drivers/serial/mpc52xx_uart.c: fix array overindexing check
[linux-2.6/mini2440.git] / mm / nommu.c
blobb571ef707428c5e171fa27b7fc09d0212018c5df
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 atomic_long_t mmap_pages_allocated;
74 EXPORT_SYMBOL(mem_map);
75 EXPORT_SYMBOL(num_physpages);
77 /* list of mapped, potentially shareable regions */
78 static struct kmem_cache *vm_region_jar;
79 struct rb_root nommu_region_tree = RB_ROOT;
80 DECLARE_RWSEM(nommu_region_sem);
82 struct vm_operations_struct generic_file_vm_ops = {
86 * Handle all mappings that got truncated by a "truncate()"
87 * system call.
89 * NOTE! We have to be ready to update the memory sharing
90 * between the file and the memory map for a potential last
91 * incomplete page. Ugly, but necessary.
93 int vmtruncate(struct inode *inode, loff_t offset)
95 struct address_space *mapping = inode->i_mapping;
96 unsigned long limit;
98 if (inode->i_size < offset)
99 goto do_expand;
100 i_size_write(inode, offset);
102 truncate_inode_pages(mapping, offset);
103 goto out_truncate;
105 do_expand:
106 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
107 if (limit != RLIM_INFINITY && offset > limit)
108 goto out_sig;
109 if (offset > inode->i_sb->s_maxbytes)
110 goto out;
111 i_size_write(inode, offset);
113 out_truncate:
114 if (inode->i_op->truncate)
115 inode->i_op->truncate(inode);
116 return 0;
117 out_sig:
118 send_sig(SIGXFSZ, current, 0);
119 out:
120 return -EFBIG;
123 EXPORT_SYMBOL(vmtruncate);
126 * Return the total memory allocated for this pointer, not
127 * just what the caller asked for.
129 * Doesn't have to be accurate, i.e. may have races.
131 unsigned int kobjsize(const void *objp)
133 struct page *page;
136 * If the object we have should not have ksize performed on it,
137 * return size of 0
139 if (!objp || !virt_addr_valid(objp))
140 return 0;
142 page = virt_to_head_page(objp);
145 * If the allocator sets PageSlab, we know the pointer came from
146 * kmalloc().
148 if (PageSlab(page))
149 return ksize(objp);
152 * If it's not a compound page, see if we have a matching VMA
153 * region. This test is intentionally done in reverse order,
154 * so if there's no VMA, we still fall through and hand back
155 * PAGE_SIZE for 0-order pages.
157 if (!PageCompound(page)) {
158 struct vm_area_struct *vma;
160 vma = find_vma(current->mm, (unsigned long)objp);
161 if (vma)
162 return vma->vm_end - vma->vm_start;
166 * The ksize() function is only guaranteed to work for pointers
167 * returned by kmalloc(). So handle arbitrary pointers here.
169 return PAGE_SIZE << compound_order(page);
172 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
173 unsigned long start, int len, int flags,
174 struct page **pages, struct vm_area_struct **vmas)
176 struct vm_area_struct *vma;
177 unsigned long vm_flags;
178 int i;
179 int write = !!(flags & GUP_FLAGS_WRITE);
180 int force = !!(flags & GUP_FLAGS_FORCE);
181 int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
183 /* calculate required read or write permissions.
184 * - if 'force' is set, we only require the "MAY" flags.
186 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
187 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
189 for (i = 0; i < len; i++) {
190 vma = find_vma(mm, start);
191 if (!vma)
192 goto finish_or_fault;
194 /* protect what we can, including chardevs */
195 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
196 (!ignore && !(vm_flags & vma->vm_flags)))
197 goto finish_or_fault;
199 if (pages) {
200 pages[i] = virt_to_page(start);
201 if (pages[i])
202 page_cache_get(pages[i]);
204 if (vmas)
205 vmas[i] = vma;
206 start += PAGE_SIZE;
209 return i;
211 finish_or_fault:
212 return i ? : -EFAULT;
217 * get a list of pages in an address range belonging to the specified process
218 * and indicate the VMA that covers each page
219 * - this is potentially dodgy as we may end incrementing the page count of a
220 * slab page or a secondary page from a compound page
221 * - don't permit access to VMAs that don't support it, such as I/O mappings
223 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
224 unsigned long start, int len, int write, int force,
225 struct page **pages, struct vm_area_struct **vmas)
227 int flags = 0;
229 if (write)
230 flags |= GUP_FLAGS_WRITE;
231 if (force)
232 flags |= GUP_FLAGS_FORCE;
234 return __get_user_pages(tsk, mm,
235 start, len, flags,
236 pages, vmas);
238 EXPORT_SYMBOL(get_user_pages);
240 DEFINE_RWLOCK(vmlist_lock);
241 struct vm_struct *vmlist;
243 void vfree(const void *addr)
245 kfree(addr);
247 EXPORT_SYMBOL(vfree);
249 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
252 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
253 * returns only a logical address.
255 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
257 EXPORT_SYMBOL(__vmalloc);
259 void *vmalloc_user(unsigned long size)
261 void *ret;
263 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
264 PAGE_KERNEL);
265 if (ret) {
266 struct vm_area_struct *vma;
268 down_write(&current->mm->mmap_sem);
269 vma = find_vma(current->mm, (unsigned long)ret);
270 if (vma)
271 vma->vm_flags |= VM_USERMAP;
272 up_write(&current->mm->mmap_sem);
275 return ret;
277 EXPORT_SYMBOL(vmalloc_user);
279 struct page *vmalloc_to_page(const void *addr)
281 return virt_to_page(addr);
283 EXPORT_SYMBOL(vmalloc_to_page);
285 unsigned long vmalloc_to_pfn(const void *addr)
287 return page_to_pfn(virt_to_page(addr));
289 EXPORT_SYMBOL(vmalloc_to_pfn);
291 long vread(char *buf, char *addr, unsigned long count)
293 memcpy(buf, addr, count);
294 return count;
297 long vwrite(char *buf, char *addr, unsigned long count)
299 /* Don't allow overflow */
300 if ((unsigned long) addr + count < count)
301 count = -(unsigned long) addr;
303 memcpy(addr, buf, count);
304 return(count);
308 * vmalloc - allocate virtually continguos memory
310 * @size: allocation size
312 * Allocate enough pages to cover @size from the page level
313 * allocator and map them into continguos kernel virtual space.
315 * For tight control over page level allocator and protection flags
316 * use __vmalloc() instead.
318 void *vmalloc(unsigned long size)
320 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
322 EXPORT_SYMBOL(vmalloc);
324 void *vmalloc_node(unsigned long size, int node)
326 return vmalloc(size);
328 EXPORT_SYMBOL(vmalloc_node);
330 #ifndef PAGE_KERNEL_EXEC
331 # define PAGE_KERNEL_EXEC PAGE_KERNEL
332 #endif
335 * vmalloc_exec - allocate virtually contiguous, executable memory
336 * @size: allocation size
338 * Kernel-internal function to allocate enough pages to cover @size
339 * the page level allocator and map them into contiguous and
340 * executable kernel virtual space.
342 * For tight control over page level allocator and protection flags
343 * use __vmalloc() instead.
346 void *vmalloc_exec(unsigned long size)
348 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
352 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
353 * @size: allocation size
355 * Allocate enough 32bit PA addressable pages to cover @size from the
356 * page level allocator and map them into continguos kernel virtual space.
358 void *vmalloc_32(unsigned long size)
360 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
362 EXPORT_SYMBOL(vmalloc_32);
365 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
366 * @size: allocation size
368 * The resulting memory area is 32bit addressable and zeroed so it can be
369 * mapped to userspace without leaking data.
371 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
372 * remap_vmalloc_range() are permissible.
374 void *vmalloc_32_user(unsigned long size)
377 * We'll have to sort out the ZONE_DMA bits for 64-bit,
378 * but for now this can simply use vmalloc_user() directly.
380 return vmalloc_user(size);
382 EXPORT_SYMBOL(vmalloc_32_user);
384 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
386 BUG();
387 return NULL;
389 EXPORT_SYMBOL(vmap);
391 void vunmap(const void *addr)
393 BUG();
395 EXPORT_SYMBOL(vunmap);
397 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
399 BUG();
400 return NULL;
402 EXPORT_SYMBOL(vm_map_ram);
404 void vm_unmap_ram(const void *mem, unsigned int count)
406 BUG();
408 EXPORT_SYMBOL(vm_unmap_ram);
410 void vm_unmap_aliases(void)
413 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
416 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
417 * have one.
419 void __attribute__((weak)) vmalloc_sync_all(void)
423 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
424 struct page *page)
426 return -EINVAL;
428 EXPORT_SYMBOL(vm_insert_page);
431 * sys_brk() for the most part doesn't need the global kernel
432 * lock, except when an application is doing something nasty
433 * like trying to un-brk an area that has already been mapped
434 * to a regular file. in this case, the unmapping will need
435 * to invoke file system routines that need the global lock.
437 SYSCALL_DEFINE1(brk, unsigned long, brk)
439 struct mm_struct *mm = current->mm;
441 if (brk < mm->start_brk || brk > mm->context.end_brk)
442 return mm->brk;
444 if (mm->brk == brk)
445 return mm->brk;
448 * Always allow shrinking brk
450 if (brk <= mm->brk) {
451 mm->brk = brk;
452 return brk;
456 * Ok, looks good - let it rip.
458 return mm->brk = brk;
462 * initialise the VMA and region record slabs
464 void __init mmap_init(void)
466 int ret;
468 ret = percpu_counter_init(&vm_committed_as, 0);
469 VM_BUG_ON(ret);
470 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
474 * validate the region tree
475 * - the caller must hold the region lock
477 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
478 static noinline void validate_nommu_regions(void)
480 struct vm_region *region, *last;
481 struct rb_node *p, *lastp;
483 lastp = rb_first(&nommu_region_tree);
484 if (!lastp)
485 return;
487 last = rb_entry(lastp, struct vm_region, vm_rb);
488 BUG_ON(unlikely(last->vm_end <= last->vm_start));
489 BUG_ON(unlikely(last->vm_top < last->vm_end));
491 while ((p = rb_next(lastp))) {
492 region = rb_entry(p, struct vm_region, vm_rb);
493 last = rb_entry(lastp, struct vm_region, vm_rb);
495 BUG_ON(unlikely(region->vm_end <= region->vm_start));
496 BUG_ON(unlikely(region->vm_top < region->vm_end));
497 BUG_ON(unlikely(region->vm_start < last->vm_top));
499 lastp = p;
502 #else
503 static void validate_nommu_regions(void)
506 #endif
509 * add a region into the global tree
511 static void add_nommu_region(struct vm_region *region)
513 struct vm_region *pregion;
514 struct rb_node **p, *parent;
516 validate_nommu_regions();
518 parent = NULL;
519 p = &nommu_region_tree.rb_node;
520 while (*p) {
521 parent = *p;
522 pregion = rb_entry(parent, struct vm_region, vm_rb);
523 if (region->vm_start < pregion->vm_start)
524 p = &(*p)->rb_left;
525 else if (region->vm_start > pregion->vm_start)
526 p = &(*p)->rb_right;
527 else if (pregion == region)
528 return;
529 else
530 BUG();
533 rb_link_node(&region->vm_rb, parent, p);
534 rb_insert_color(&region->vm_rb, &nommu_region_tree);
536 validate_nommu_regions();
540 * delete a region from the global tree
542 static void delete_nommu_region(struct vm_region *region)
544 BUG_ON(!nommu_region_tree.rb_node);
546 validate_nommu_regions();
547 rb_erase(&region->vm_rb, &nommu_region_tree);
548 validate_nommu_regions();
552 * free a contiguous series of pages
554 static void free_page_series(unsigned long from, unsigned long to)
556 for (; from < to; from += PAGE_SIZE) {
557 struct page *page = virt_to_page(from);
559 kdebug("- free %lx", from);
560 atomic_long_dec(&mmap_pages_allocated);
561 if (page_count(page) != 1)
562 kdebug("free page %p: refcount not one: %d",
563 page, page_count(page));
564 put_page(page);
569 * release a reference to a region
570 * - the caller must hold the region semaphore for writing, which this releases
571 * - the region may not have been added to the tree yet, in which case vm_top
572 * will equal vm_start
574 static void __put_nommu_region(struct vm_region *region)
575 __releases(nommu_region_sem)
577 kenter("%p{%d}", region, atomic_read(&region->vm_usage));
579 BUG_ON(!nommu_region_tree.rb_node);
581 if (atomic_dec_and_test(&region->vm_usage)) {
582 if (region->vm_top > region->vm_start)
583 delete_nommu_region(region);
584 up_write(&nommu_region_sem);
586 if (region->vm_file)
587 fput(region->vm_file);
589 /* IO memory and memory shared directly out of the pagecache
590 * from ramfs/tmpfs mustn't be released here */
591 if (region->vm_flags & VM_MAPPED_COPY) {
592 kdebug("free series");
593 free_page_series(region->vm_start, region->vm_top);
595 kmem_cache_free(vm_region_jar, region);
596 } else {
597 up_write(&nommu_region_sem);
602 * release a reference to a region
604 static void put_nommu_region(struct vm_region *region)
606 down_write(&nommu_region_sem);
607 __put_nommu_region(region);
611 * add a VMA into a process's mm_struct in the appropriate place in the list
612 * and tree and add to the address space's page tree also if not an anonymous
613 * page
614 * - should be called with mm->mmap_sem held writelocked
616 static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
618 struct vm_area_struct *pvma, **pp;
619 struct address_space *mapping;
620 struct rb_node **p, *parent;
622 kenter(",%p", vma);
624 BUG_ON(!vma->vm_region);
626 mm->map_count++;
627 vma->vm_mm = mm;
629 /* add the VMA to the mapping */
630 if (vma->vm_file) {
631 mapping = vma->vm_file->f_mapping;
633 flush_dcache_mmap_lock(mapping);
634 vma_prio_tree_insert(vma, &mapping->i_mmap);
635 flush_dcache_mmap_unlock(mapping);
638 /* add the VMA to the tree */
639 parent = NULL;
640 p = &mm->mm_rb.rb_node;
641 while (*p) {
642 parent = *p;
643 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
645 /* sort by: start addr, end addr, VMA struct addr in that order
646 * (the latter is necessary as we may get identical VMAs) */
647 if (vma->vm_start < pvma->vm_start)
648 p = &(*p)->rb_left;
649 else if (vma->vm_start > pvma->vm_start)
650 p = &(*p)->rb_right;
651 else if (vma->vm_end < pvma->vm_end)
652 p = &(*p)->rb_left;
653 else if (vma->vm_end > pvma->vm_end)
654 p = &(*p)->rb_right;
655 else if (vma < pvma)
656 p = &(*p)->rb_left;
657 else if (vma > pvma)
658 p = &(*p)->rb_right;
659 else
660 BUG();
663 rb_link_node(&vma->vm_rb, parent, p);
664 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
666 /* add VMA to the VMA list also */
667 for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
668 if (pvma->vm_start > vma->vm_start)
669 break;
670 if (pvma->vm_start < vma->vm_start)
671 continue;
672 if (pvma->vm_end < vma->vm_end)
673 break;
676 vma->vm_next = *pp;
677 *pp = vma;
681 * delete a VMA from its owning mm_struct and address space
683 static void delete_vma_from_mm(struct vm_area_struct *vma)
685 struct vm_area_struct **pp;
686 struct address_space *mapping;
687 struct mm_struct *mm = vma->vm_mm;
689 kenter("%p", vma);
691 mm->map_count--;
692 if (mm->mmap_cache == vma)
693 mm->mmap_cache = NULL;
695 /* remove the VMA from the mapping */
696 if (vma->vm_file) {
697 mapping = vma->vm_file->f_mapping;
699 flush_dcache_mmap_lock(mapping);
700 vma_prio_tree_remove(vma, &mapping->i_mmap);
701 flush_dcache_mmap_unlock(mapping);
704 /* remove from the MM's tree and list */
705 rb_erase(&vma->vm_rb, &mm->mm_rb);
706 for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
707 if (*pp == vma) {
708 *pp = vma->vm_next;
709 break;
713 vma->vm_mm = NULL;
717 * destroy a VMA record
719 static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
721 kenter("%p", vma);
722 if (vma->vm_ops && vma->vm_ops->close)
723 vma->vm_ops->close(vma);
724 if (vma->vm_file) {
725 fput(vma->vm_file);
726 if (vma->vm_flags & VM_EXECUTABLE)
727 removed_exe_file_vma(mm);
729 put_nommu_region(vma->vm_region);
730 kmem_cache_free(vm_area_cachep, vma);
734 * look up the first VMA in which addr resides, NULL if none
735 * - should be called with mm->mmap_sem at least held readlocked
737 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
739 struct vm_area_struct *vma;
740 struct rb_node *n = mm->mm_rb.rb_node;
742 /* check the cache first */
743 vma = mm->mmap_cache;
744 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
745 return vma;
747 /* trawl the tree (there may be multiple mappings in which addr
748 * resides) */
749 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
750 vma = rb_entry(n, struct vm_area_struct, vm_rb);
751 if (vma->vm_start > addr)
752 return NULL;
753 if (vma->vm_end > addr) {
754 mm->mmap_cache = vma;
755 return vma;
759 return NULL;
761 EXPORT_SYMBOL(find_vma);
764 * find a VMA
765 * - we don't extend stack VMAs under NOMMU conditions
767 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
769 return find_vma(mm, addr);
773 * expand a stack to a given address
774 * - not supported under NOMMU conditions
776 int expand_stack(struct vm_area_struct *vma, unsigned long address)
778 return -ENOMEM;
782 * look up the first VMA exactly that exactly matches addr
783 * - should be called with mm->mmap_sem at least held readlocked
785 static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
786 unsigned long addr,
787 unsigned long len)
789 struct vm_area_struct *vma;
790 struct rb_node *n = mm->mm_rb.rb_node;
791 unsigned long end = addr + len;
793 /* check the cache first */
794 vma = mm->mmap_cache;
795 if (vma && vma->vm_start == addr && vma->vm_end == end)
796 return vma;
798 /* trawl the tree (there may be multiple mappings in which addr
799 * resides) */
800 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
801 vma = rb_entry(n, struct vm_area_struct, vm_rb);
802 if (vma->vm_start < addr)
803 continue;
804 if (vma->vm_start > addr)
805 return NULL;
806 if (vma->vm_end == end) {
807 mm->mmap_cache = vma;
808 return vma;
812 return NULL;
816 * determine whether a mapping should be permitted and, if so, what sort of
817 * mapping we're capable of supporting
819 static int validate_mmap_request(struct file *file,
820 unsigned long addr,
821 unsigned long len,
822 unsigned long prot,
823 unsigned long flags,
824 unsigned long pgoff,
825 unsigned long *_capabilities)
827 unsigned long capabilities, rlen;
828 unsigned long reqprot = prot;
829 int ret;
831 /* do the simple checks first */
832 if (flags & MAP_FIXED || addr) {
833 printk(KERN_DEBUG
834 "%d: Can't do fixed-address/overlay mmap of RAM\n",
835 current->pid);
836 return -EINVAL;
839 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
840 (flags & MAP_TYPE) != MAP_SHARED)
841 return -EINVAL;
843 if (!len)
844 return -EINVAL;
846 /* Careful about overflows.. */
847 rlen = PAGE_ALIGN(len);
848 if (!rlen || rlen > TASK_SIZE)
849 return -ENOMEM;
851 /* offset overflow? */
852 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
853 return -EOVERFLOW;
855 if (file) {
856 /* validate file mapping requests */
857 struct address_space *mapping;
859 /* files must support mmap */
860 if (!file->f_op || !file->f_op->mmap)
861 return -ENODEV;
863 /* work out if what we've got could possibly be shared
864 * - we support chardevs that provide their own "memory"
865 * - we support files/blockdevs that are memory backed
867 mapping = file->f_mapping;
868 if (!mapping)
869 mapping = file->f_path.dentry->d_inode->i_mapping;
871 capabilities = 0;
872 if (mapping && mapping->backing_dev_info)
873 capabilities = mapping->backing_dev_info->capabilities;
875 if (!capabilities) {
876 /* no explicit capabilities set, so assume some
877 * defaults */
878 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
879 case S_IFREG:
880 case S_IFBLK:
881 capabilities = BDI_CAP_MAP_COPY;
882 break;
884 case S_IFCHR:
885 capabilities =
886 BDI_CAP_MAP_DIRECT |
887 BDI_CAP_READ_MAP |
888 BDI_CAP_WRITE_MAP;
889 break;
891 default:
892 return -EINVAL;
896 /* eliminate any capabilities that we can't support on this
897 * device */
898 if (!file->f_op->get_unmapped_area)
899 capabilities &= ~BDI_CAP_MAP_DIRECT;
900 if (!file->f_op->read)
901 capabilities &= ~BDI_CAP_MAP_COPY;
903 if (flags & MAP_SHARED) {
904 /* do checks for writing, appending and locking */
905 if ((prot & PROT_WRITE) &&
906 !(file->f_mode & FMODE_WRITE))
907 return -EACCES;
909 if (IS_APPEND(file->f_path.dentry->d_inode) &&
910 (file->f_mode & FMODE_WRITE))
911 return -EACCES;
913 if (locks_verify_locked(file->f_path.dentry->d_inode))
914 return -EAGAIN;
916 if (!(capabilities & BDI_CAP_MAP_DIRECT))
917 return -ENODEV;
919 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
920 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
921 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
923 printk("MAP_SHARED not completely supported on !MMU\n");
924 return -EINVAL;
927 /* we mustn't privatise shared mappings */
928 capabilities &= ~BDI_CAP_MAP_COPY;
930 else {
931 /* we're going to read the file into private memory we
932 * allocate */
933 if (!(capabilities & BDI_CAP_MAP_COPY))
934 return -ENODEV;
936 /* we don't permit a private writable mapping to be
937 * shared with the backing device */
938 if (prot & PROT_WRITE)
939 capabilities &= ~BDI_CAP_MAP_DIRECT;
942 /* handle executable mappings and implied executable
943 * mappings */
944 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
945 if (prot & PROT_EXEC)
946 return -EPERM;
948 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
949 /* handle implication of PROT_EXEC by PROT_READ */
950 if (current->personality & READ_IMPLIES_EXEC) {
951 if (capabilities & BDI_CAP_EXEC_MAP)
952 prot |= PROT_EXEC;
955 else if ((prot & PROT_READ) &&
956 (prot & PROT_EXEC) &&
957 !(capabilities & BDI_CAP_EXEC_MAP)
959 /* backing file is not executable, try to copy */
960 capabilities &= ~BDI_CAP_MAP_DIRECT;
963 else {
964 /* anonymous mappings are always memory backed and can be
965 * privately mapped
967 capabilities = BDI_CAP_MAP_COPY;
969 /* handle PROT_EXEC implication by PROT_READ */
970 if ((prot & PROT_READ) &&
971 (current->personality & READ_IMPLIES_EXEC))
972 prot |= PROT_EXEC;
975 /* allow the security API to have its say */
976 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
977 if (ret < 0)
978 return ret;
980 /* looks okay */
981 *_capabilities = capabilities;
982 return 0;
986 * we've determined that we can make the mapping, now translate what we
987 * now know into VMA flags
989 static unsigned long determine_vm_flags(struct file *file,
990 unsigned long prot,
991 unsigned long flags,
992 unsigned long capabilities)
994 unsigned long vm_flags;
996 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
997 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
998 /* vm_flags |= mm->def_flags; */
1000 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1001 /* attempt to share read-only copies of mapped file chunks */
1002 if (file && !(prot & PROT_WRITE))
1003 vm_flags |= VM_MAYSHARE;
1005 else {
1006 /* overlay a shareable mapping on the backing device or inode
1007 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1008 * romfs/cramfs */
1009 if (flags & MAP_SHARED)
1010 vm_flags |= VM_MAYSHARE | VM_SHARED;
1011 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1012 vm_flags |= VM_MAYSHARE;
1015 /* refuse to let anyone share private mappings with this process if
1016 * it's being traced - otherwise breakpoints set in it may interfere
1017 * with another untraced process
1019 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
1020 vm_flags &= ~VM_MAYSHARE;
1022 return vm_flags;
1026 * set up a shared mapping on a file (the driver or filesystem provides and
1027 * pins the storage)
1029 static int do_mmap_shared_file(struct vm_area_struct *vma)
1031 int ret;
1033 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1034 if (ret == 0) {
1035 vma->vm_region->vm_top = vma->vm_region->vm_end;
1036 return ret;
1038 if (ret != -ENOSYS)
1039 return ret;
1041 /* getting an ENOSYS error indicates that direct mmap isn't
1042 * possible (as opposed to tried but failed) so we'll fall
1043 * through to making a private copy of the data and mapping
1044 * that if we can */
1045 return -ENODEV;
1049 * set up a private mapping or an anonymous shared mapping
1051 static int do_mmap_private(struct vm_area_struct *vma,
1052 struct vm_region *region,
1053 unsigned long len)
1055 struct page *pages;
1056 unsigned long total, point, n, rlen;
1057 void *base;
1058 int ret, order;
1060 /* invoke the file's mapping function so that it can keep track of
1061 * shared mappings on devices or memory
1062 * - VM_MAYSHARE will be set if it may attempt to share
1064 if (vma->vm_file) {
1065 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1066 if (ret == 0) {
1067 /* shouldn't return success if we're not sharing */
1068 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1069 vma->vm_region->vm_top = vma->vm_region->vm_end;
1070 return ret;
1072 if (ret != -ENOSYS)
1073 return ret;
1075 /* getting an ENOSYS error indicates that direct mmap isn't
1076 * possible (as opposed to tried but failed) so we'll try to
1077 * make a private copy of the data and map that instead */
1080 rlen = PAGE_ALIGN(len);
1082 /* allocate some memory to hold the mapping
1083 * - note that this may not return a page-aligned address if the object
1084 * we're allocating is smaller than a page
1086 order = get_order(rlen);
1087 kdebug("alloc order %d for %lx", order, len);
1089 pages = alloc_pages(GFP_KERNEL, order);
1090 if (!pages)
1091 goto enomem;
1093 total = 1 << order;
1094 atomic_long_add(total, &mmap_pages_allocated);
1096 point = rlen >> PAGE_SHIFT;
1098 /* we allocated a power-of-2 sized page set, so we may want to trim off
1099 * the excess */
1100 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1101 while (total > point) {
1102 order = ilog2(total - point);
1103 n = 1 << order;
1104 kdebug("shave %lu/%lu @%lu", n, total - point, total);
1105 atomic_long_sub(n, &mmap_pages_allocated);
1106 total -= n;
1107 set_page_refcounted(pages + total);
1108 __free_pages(pages + total, order);
1112 for (point = 1; point < total; point++)
1113 set_page_refcounted(&pages[point]);
1115 base = page_address(pages);
1116 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1117 region->vm_start = (unsigned long) base;
1118 region->vm_end = region->vm_start + rlen;
1119 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1121 vma->vm_start = region->vm_start;
1122 vma->vm_end = region->vm_start + len;
1124 if (vma->vm_file) {
1125 /* read the contents of a file into the copy */
1126 mm_segment_t old_fs;
1127 loff_t fpos;
1129 fpos = vma->vm_pgoff;
1130 fpos <<= PAGE_SHIFT;
1132 old_fs = get_fs();
1133 set_fs(KERNEL_DS);
1134 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
1135 set_fs(old_fs);
1137 if (ret < 0)
1138 goto error_free;
1140 /* clear the last little bit */
1141 if (ret < rlen)
1142 memset(base + ret, 0, rlen - ret);
1144 } else {
1145 /* if it's an anonymous mapping, then just clear it */
1146 memset(base, 0, rlen);
1149 return 0;
1151 error_free:
1152 free_page_series(region->vm_start, region->vm_end);
1153 region->vm_start = vma->vm_start = 0;
1154 region->vm_end = vma->vm_end = 0;
1155 region->vm_top = 0;
1156 return ret;
1158 enomem:
1159 printk("Allocation of length %lu from process %d (%s) failed\n",
1160 len, current->pid, current->comm);
1161 show_free_areas();
1162 return -ENOMEM;
1166 * handle mapping creation for uClinux
1168 unsigned long do_mmap_pgoff(struct file *file,
1169 unsigned long addr,
1170 unsigned long len,
1171 unsigned long prot,
1172 unsigned long flags,
1173 unsigned long pgoff)
1175 struct vm_area_struct *vma;
1176 struct vm_region *region;
1177 struct rb_node *rb;
1178 unsigned long capabilities, vm_flags, result;
1179 int ret;
1181 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1183 if (!(flags & MAP_FIXED))
1184 addr = round_hint_to_min(addr);
1186 /* decide whether we should attempt the mapping, and if so what sort of
1187 * mapping */
1188 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1189 &capabilities);
1190 if (ret < 0) {
1191 kleave(" = %d [val]", ret);
1192 return ret;
1195 /* we've determined that we can make the mapping, now translate what we
1196 * now know into VMA flags */
1197 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1199 /* we're going to need to record the mapping */
1200 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1201 if (!region)
1202 goto error_getting_region;
1204 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1205 if (!vma)
1206 goto error_getting_vma;
1208 atomic_set(&region->vm_usage, 1);
1209 region->vm_flags = vm_flags;
1210 region->vm_pgoff = pgoff;
1212 INIT_LIST_HEAD(&vma->anon_vma_node);
1213 vma->vm_flags = vm_flags;
1214 vma->vm_pgoff = pgoff;
1216 if (file) {
1217 region->vm_file = file;
1218 get_file(file);
1219 vma->vm_file = file;
1220 get_file(file);
1221 if (vm_flags & VM_EXECUTABLE) {
1222 added_exe_file_vma(current->mm);
1223 vma->vm_mm = current->mm;
1227 down_write(&nommu_region_sem);
1229 /* if we want to share, we need to check for regions created by other
1230 * mmap() calls that overlap with our proposed mapping
1231 * - we can only share with a superset match on most regular files
1232 * - shared mappings on character devices and memory backed files are
1233 * permitted to overlap inexactly as far as we are concerned for in
1234 * these cases, sharing is handled in the driver or filesystem rather
1235 * than here
1237 if (vm_flags & VM_MAYSHARE) {
1238 struct vm_region *pregion;
1239 unsigned long pglen, rpglen, pgend, rpgend, start;
1241 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1242 pgend = pgoff + pglen;
1244 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1245 pregion = rb_entry(rb, struct vm_region, vm_rb);
1247 if (!(pregion->vm_flags & VM_MAYSHARE))
1248 continue;
1250 /* search for overlapping mappings on the same file */
1251 if (pregion->vm_file->f_path.dentry->d_inode !=
1252 file->f_path.dentry->d_inode)
1253 continue;
1255 if (pregion->vm_pgoff >= pgend)
1256 continue;
1258 rpglen = pregion->vm_end - pregion->vm_start;
1259 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1260 rpgend = pregion->vm_pgoff + rpglen;
1261 if (pgoff >= rpgend)
1262 continue;
1264 /* handle inexactly overlapping matches between
1265 * mappings */
1266 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1267 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1268 /* new mapping is not a subset of the region */
1269 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1270 goto sharing_violation;
1271 continue;
1274 /* we've found a region we can share */
1275 atomic_inc(&pregion->vm_usage);
1276 vma->vm_region = pregion;
1277 start = pregion->vm_start;
1278 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1279 vma->vm_start = start;
1280 vma->vm_end = start + len;
1282 if (pregion->vm_flags & VM_MAPPED_COPY) {
1283 kdebug("share copy");
1284 vma->vm_flags |= VM_MAPPED_COPY;
1285 } else {
1286 kdebug("share mmap");
1287 ret = do_mmap_shared_file(vma);
1288 if (ret < 0) {
1289 vma->vm_region = NULL;
1290 vma->vm_start = 0;
1291 vma->vm_end = 0;
1292 atomic_dec(&pregion->vm_usage);
1293 pregion = NULL;
1294 goto error_just_free;
1297 fput(region->vm_file);
1298 kmem_cache_free(vm_region_jar, region);
1299 region = pregion;
1300 result = start;
1301 goto share;
1304 /* obtain the address at which to make a shared mapping
1305 * - this is the hook for quasi-memory character devices to
1306 * tell us the location of a shared mapping
1308 if (file && file->f_op->get_unmapped_area) {
1309 addr = file->f_op->get_unmapped_area(file, addr, len,
1310 pgoff, flags);
1311 if (IS_ERR((void *) addr)) {
1312 ret = addr;
1313 if (ret != (unsigned long) -ENOSYS)
1314 goto error_just_free;
1316 /* the driver refused to tell us where to site
1317 * the mapping so we'll have to attempt to copy
1318 * it */
1319 ret = (unsigned long) -ENODEV;
1320 if (!(capabilities & BDI_CAP_MAP_COPY))
1321 goto error_just_free;
1323 capabilities &= ~BDI_CAP_MAP_DIRECT;
1324 } else {
1325 vma->vm_start = region->vm_start = addr;
1326 vma->vm_end = region->vm_end = addr + len;
1331 vma->vm_region = region;
1333 /* set up the mapping */
1334 if (file && vma->vm_flags & VM_SHARED)
1335 ret = do_mmap_shared_file(vma);
1336 else
1337 ret = do_mmap_private(vma, region, len);
1338 if (ret < 0)
1339 goto error_put_region;
1341 add_nommu_region(region);
1343 /* okay... we have a mapping; now we have to register it */
1344 result = vma->vm_start;
1346 current->mm->total_vm += len >> PAGE_SHIFT;
1348 share:
1349 add_vma_to_mm(current->mm, vma);
1351 up_write(&nommu_region_sem);
1353 if (prot & PROT_EXEC)
1354 flush_icache_range(result, result + len);
1356 kleave(" = %lx", result);
1357 return result;
1359 error_put_region:
1360 __put_nommu_region(region);
1361 if (vma) {
1362 if (vma->vm_file) {
1363 fput(vma->vm_file);
1364 if (vma->vm_flags & VM_EXECUTABLE)
1365 removed_exe_file_vma(vma->vm_mm);
1367 kmem_cache_free(vm_area_cachep, vma);
1369 kleave(" = %d [pr]", ret);
1370 return ret;
1372 error_just_free:
1373 up_write(&nommu_region_sem);
1374 error:
1375 fput(region->vm_file);
1376 kmem_cache_free(vm_region_jar, region);
1377 fput(vma->vm_file);
1378 if (vma->vm_flags & VM_EXECUTABLE)
1379 removed_exe_file_vma(vma->vm_mm);
1380 kmem_cache_free(vm_area_cachep, vma);
1381 kleave(" = %d", ret);
1382 return ret;
1384 sharing_violation:
1385 up_write(&nommu_region_sem);
1386 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1387 ret = -EINVAL;
1388 goto error;
1390 error_getting_vma:
1391 kmem_cache_free(vm_region_jar, region);
1392 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1393 " from process %d failed\n",
1394 len, current->pid);
1395 show_free_areas();
1396 return -ENOMEM;
1398 error_getting_region:
1399 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1400 " from process %d failed\n",
1401 len, current->pid);
1402 show_free_areas();
1403 return -ENOMEM;
1405 EXPORT_SYMBOL(do_mmap_pgoff);
1408 * split a vma into two pieces at address 'addr', a new vma is allocated either
1409 * for the first part or the tail.
1411 int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1412 unsigned long addr, int new_below)
1414 struct vm_area_struct *new;
1415 struct vm_region *region;
1416 unsigned long npages;
1418 kenter("");
1420 /* we're only permitted to split anonymous regions that have a single
1421 * owner */
1422 if (vma->vm_file ||
1423 atomic_read(&vma->vm_region->vm_usage) != 1)
1424 return -ENOMEM;
1426 if (mm->map_count >= sysctl_max_map_count)
1427 return -ENOMEM;
1429 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1430 if (!region)
1431 return -ENOMEM;
1433 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1434 if (!new) {
1435 kmem_cache_free(vm_region_jar, region);
1436 return -ENOMEM;
1439 /* most fields are the same, copy all, and then fixup */
1440 *new = *vma;
1441 *region = *vma->vm_region;
1442 new->vm_region = region;
1444 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1446 if (new_below) {
1447 region->vm_top = region->vm_end = new->vm_end = addr;
1448 } else {
1449 region->vm_start = new->vm_start = addr;
1450 region->vm_pgoff = new->vm_pgoff += npages;
1453 if (new->vm_ops && new->vm_ops->open)
1454 new->vm_ops->open(new);
1456 delete_vma_from_mm(vma);
1457 down_write(&nommu_region_sem);
1458 delete_nommu_region(vma->vm_region);
1459 if (new_below) {
1460 vma->vm_region->vm_start = vma->vm_start = addr;
1461 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1462 } else {
1463 vma->vm_region->vm_end = vma->vm_end = addr;
1464 vma->vm_region->vm_top = addr;
1466 add_nommu_region(vma->vm_region);
1467 add_nommu_region(new->vm_region);
1468 up_write(&nommu_region_sem);
1469 add_vma_to_mm(mm, vma);
1470 add_vma_to_mm(mm, new);
1471 return 0;
1475 * shrink a VMA by removing the specified chunk from either the beginning or
1476 * the end
1478 static int shrink_vma(struct mm_struct *mm,
1479 struct vm_area_struct *vma,
1480 unsigned long from, unsigned long to)
1482 struct vm_region *region;
1484 kenter("");
1486 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1487 * and list */
1488 delete_vma_from_mm(vma);
1489 if (from > vma->vm_start)
1490 vma->vm_end = from;
1491 else
1492 vma->vm_start = to;
1493 add_vma_to_mm(mm, vma);
1495 /* cut the backing region down to size */
1496 region = vma->vm_region;
1497 BUG_ON(atomic_read(&region->vm_usage) != 1);
1499 down_write(&nommu_region_sem);
1500 delete_nommu_region(region);
1501 if (from > region->vm_start) {
1502 to = region->vm_top;
1503 region->vm_top = region->vm_end = from;
1504 } else {
1505 region->vm_start = to;
1507 add_nommu_region(region);
1508 up_write(&nommu_region_sem);
1510 free_page_series(from, to);
1511 return 0;
1515 * release a mapping
1516 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1517 * VMA, though it need not cover the whole VMA
1519 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1521 struct vm_area_struct *vma;
1522 struct rb_node *rb;
1523 unsigned long end = start + len;
1524 int ret;
1526 kenter(",%lx,%zx", start, len);
1528 if (len == 0)
1529 return -EINVAL;
1531 /* find the first potentially overlapping VMA */
1532 vma = find_vma(mm, start);
1533 if (!vma) {
1534 static int limit = 0;
1535 if (limit < 5) {
1536 printk(KERN_WARNING
1537 "munmap of memory not mmapped by process %d"
1538 " (%s): 0x%lx-0x%lx\n",
1539 current->pid, current->comm,
1540 start, start + len - 1);
1541 limit++;
1543 return -EINVAL;
1546 /* we're allowed to split an anonymous VMA but not a file-backed one */
1547 if (vma->vm_file) {
1548 do {
1549 if (start > vma->vm_start) {
1550 kleave(" = -EINVAL [miss]");
1551 return -EINVAL;
1553 if (end == vma->vm_end)
1554 goto erase_whole_vma;
1555 rb = rb_next(&vma->vm_rb);
1556 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1557 } while (rb);
1558 kleave(" = -EINVAL [split file]");
1559 return -EINVAL;
1560 } else {
1561 /* the chunk must be a subset of the VMA found */
1562 if (start == vma->vm_start && end == vma->vm_end)
1563 goto erase_whole_vma;
1564 if (start < vma->vm_start || end > vma->vm_end) {
1565 kleave(" = -EINVAL [superset]");
1566 return -EINVAL;
1568 if (start & ~PAGE_MASK) {
1569 kleave(" = -EINVAL [unaligned start]");
1570 return -EINVAL;
1572 if (end != vma->vm_end && end & ~PAGE_MASK) {
1573 kleave(" = -EINVAL [unaligned split]");
1574 return -EINVAL;
1576 if (start != vma->vm_start && end != vma->vm_end) {
1577 ret = split_vma(mm, vma, start, 1);
1578 if (ret < 0) {
1579 kleave(" = %d [split]", ret);
1580 return ret;
1583 return shrink_vma(mm, vma, start, end);
1586 erase_whole_vma:
1587 delete_vma_from_mm(vma);
1588 delete_vma(mm, vma);
1589 kleave(" = 0");
1590 return 0;
1592 EXPORT_SYMBOL(do_munmap);
1594 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1596 int ret;
1597 struct mm_struct *mm = current->mm;
1599 down_write(&mm->mmap_sem);
1600 ret = do_munmap(mm, addr, len);
1601 up_write(&mm->mmap_sem);
1602 return ret;
1606 * release all the mappings made in a process's VM space
1608 void exit_mmap(struct mm_struct *mm)
1610 struct vm_area_struct *vma;
1612 if (!mm)
1613 return;
1615 kenter("");
1617 mm->total_vm = 0;
1619 while ((vma = mm->mmap)) {
1620 mm->mmap = vma->vm_next;
1621 delete_vma_from_mm(vma);
1622 delete_vma(mm, vma);
1625 kleave("");
1628 unsigned long do_brk(unsigned long addr, unsigned long len)
1630 return -ENOMEM;
1634 * expand (or shrink) an existing mapping, potentially moving it at the same
1635 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1637 * under NOMMU conditions, we only permit changing a mapping's size, and only
1638 * as long as it stays within the region allocated by do_mmap_private() and the
1639 * block is not shareable
1641 * MREMAP_FIXED is not supported under NOMMU conditions
1643 unsigned long do_mremap(unsigned long addr,
1644 unsigned long old_len, unsigned long new_len,
1645 unsigned long flags, unsigned long new_addr)
1647 struct vm_area_struct *vma;
1649 /* insanity checks first */
1650 if (old_len == 0 || new_len == 0)
1651 return (unsigned long) -EINVAL;
1653 if (addr & ~PAGE_MASK)
1654 return -EINVAL;
1656 if (flags & MREMAP_FIXED && new_addr != addr)
1657 return (unsigned long) -EINVAL;
1659 vma = find_vma_exact(current->mm, addr, old_len);
1660 if (!vma)
1661 return (unsigned long) -EINVAL;
1663 if (vma->vm_end != vma->vm_start + old_len)
1664 return (unsigned long) -EFAULT;
1666 if (vma->vm_flags & VM_MAYSHARE)
1667 return (unsigned long) -EPERM;
1669 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1670 return (unsigned long) -ENOMEM;
1672 /* all checks complete - do it */
1673 vma->vm_end = vma->vm_start + new_len;
1674 return vma->vm_start;
1676 EXPORT_SYMBOL(do_mremap);
1678 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1679 unsigned long, new_len, unsigned long, flags,
1680 unsigned long, new_addr)
1682 unsigned long ret;
1684 down_write(&current->mm->mmap_sem);
1685 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1686 up_write(&current->mm->mmap_sem);
1687 return ret;
1690 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1691 unsigned int foll_flags)
1693 return NULL;
1696 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1697 unsigned long to, unsigned long size, pgprot_t prot)
1699 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1700 return 0;
1702 EXPORT_SYMBOL(remap_pfn_range);
1704 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1705 unsigned long pgoff)
1707 unsigned int size = vma->vm_end - vma->vm_start;
1709 if (!(vma->vm_flags & VM_USERMAP))
1710 return -EINVAL;
1712 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1713 vma->vm_end = vma->vm_start + size;
1715 return 0;
1717 EXPORT_SYMBOL(remap_vmalloc_range);
1719 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1723 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1724 unsigned long len, unsigned long pgoff, unsigned long flags)
1726 return -ENOMEM;
1729 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1733 void unmap_mapping_range(struct address_space *mapping,
1734 loff_t const holebegin, loff_t const holelen,
1735 int even_cows)
1738 EXPORT_SYMBOL(unmap_mapping_range);
1741 * ask for an unmapped area at which to create a mapping on a file
1743 unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1744 unsigned long len, unsigned long pgoff,
1745 unsigned long flags)
1747 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1748 unsigned long, unsigned long);
1750 get_area = current->mm->get_unmapped_area;
1751 if (file && file->f_op && file->f_op->get_unmapped_area)
1752 get_area = file->f_op->get_unmapped_area;
1754 if (!get_area)
1755 return -ENOSYS;
1757 return get_area(file, addr, len, pgoff, flags);
1759 EXPORT_SYMBOL(get_unmapped_area);
1762 * Check that a process has enough memory to allocate a new virtual
1763 * mapping. 0 means there is enough memory for the allocation to
1764 * succeed and -ENOMEM implies there is not.
1766 * We currently support three overcommit policies, which are set via the
1767 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1769 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1770 * Additional code 2002 Jul 20 by Robert Love.
1772 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1774 * Note this is a helper function intended to be used by LSMs which
1775 * wish to use this logic.
1777 int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1779 unsigned long free, allowed;
1781 vm_acct_memory(pages);
1784 * Sometimes we want to use more memory than we have
1786 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1787 return 0;
1789 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1790 unsigned long n;
1792 free = global_page_state(NR_FILE_PAGES);
1793 free += nr_swap_pages;
1796 * Any slabs which are created with the
1797 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1798 * which are reclaimable, under pressure. The dentry
1799 * cache and most inode caches should fall into this
1801 free += global_page_state(NR_SLAB_RECLAIMABLE);
1804 * Leave the last 3% for root
1806 if (!cap_sys_admin)
1807 free -= free / 32;
1809 if (free > pages)
1810 return 0;
1813 * nr_free_pages() is very expensive on large systems,
1814 * only call if we're about to fail.
1816 n = nr_free_pages();
1819 * Leave reserved pages. The pages are not for anonymous pages.
1821 if (n <= totalreserve_pages)
1822 goto error;
1823 else
1824 n -= totalreserve_pages;
1827 * Leave the last 3% for root
1829 if (!cap_sys_admin)
1830 n -= n / 32;
1831 free += n;
1833 if (free > pages)
1834 return 0;
1836 goto error;
1839 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1841 * Leave the last 3% for root
1843 if (!cap_sys_admin)
1844 allowed -= allowed / 32;
1845 allowed += total_swap_pages;
1847 /* Don't let a single process grow too big:
1848 leave 3% of the size of this process for other processes */
1849 if (mm)
1850 allowed -= mm->total_vm / 32;
1852 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1853 return 0;
1855 error:
1856 vm_unacct_memory(pages);
1858 return -ENOMEM;
1861 int in_gate_area_no_task(unsigned long addr)
1863 return 0;
1866 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1868 BUG();
1869 return 0;
1871 EXPORT_SYMBOL(filemap_fault);
1874 * Access another process' address space.
1875 * - source/target buffer must be kernel space
1877 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1879 struct vm_area_struct *vma;
1880 struct mm_struct *mm;
1882 if (addr + len < addr)
1883 return 0;
1885 mm = get_task_mm(tsk);
1886 if (!mm)
1887 return 0;
1889 down_read(&mm->mmap_sem);
1891 /* the access must start within one of the target process's mappings */
1892 vma = find_vma(mm, addr);
1893 if (vma) {
1894 /* don't overrun this mapping */
1895 if (addr + len >= vma->vm_end)
1896 len = vma->vm_end - addr;
1898 /* only read or write mappings where it is permitted */
1899 if (write && vma->vm_flags & VM_MAYWRITE)
1900 len -= copy_to_user((void *) addr, buf, len);
1901 else if (!write && vma->vm_flags & VM_MAYREAD)
1902 len -= copy_from_user(buf, (void *) addr, len);
1903 else
1904 len = 0;
1905 } else {
1906 len = 0;
1909 up_read(&mm->mmap_sem);
1910 mmput(mm);
1911 return len;