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1/*
2 * linux/mm/nommu.c
3 *
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).
6 *
7 * See Documentation/nommu-mmap.txt
8 *
9 * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
10 * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
11 * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
12 * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
13 * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
14 */
15
16#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
17
18#include <linux/export.h>
19#include <linux/mm.h>
20#include <linux/sched/mm.h>
21#include <linux/vmacache.h>
22#include <linux/mman.h>
23#include <linux/swap.h>
24#include <linux/file.h>
25#include <linux/highmem.h>
26#include <linux/pagemap.h>
27#include <linux/slab.h>
28#include <linux/vmalloc.h>
29#include <linux/blkdev.h>
30#include <linux/backing-dev.h>
31#include <linux/compiler.h>
32#include <linux/mount.h>
33#include <linux/personality.h>
34#include <linux/security.h>
35#include <linux/syscalls.h>
36#include <linux/audit.h>
37#include <linux/printk.h>
38
39#include <linux/uaccess.h>
40#include <asm/tlb.h>
41#include <asm/tlbflush.h>
42#include <asm/mmu_context.h>
43#include "internal.h"
44
45void *high_memory;
46EXPORT_SYMBOL(high_memory);
47struct page *mem_map;
48unsigned long max_mapnr;
49EXPORT_SYMBOL(max_mapnr);
50unsigned long highest_memmap_pfn;
51int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
52int heap_stack_gap = 0;
53
54atomic_long_t mmap_pages_allocated;
55
56EXPORT_SYMBOL(mem_map);
57
58/* list of mapped, potentially shareable regions */
59static struct kmem_cache *vm_region_jar;
60struct rb_root nommu_region_tree = RB_ROOT;
61DECLARE_RWSEM(nommu_region_sem);
62
63const struct vm_operations_struct generic_file_vm_ops = {
64};
65
66/*
67 * Return the total memory allocated for this pointer, not
68 * just what the caller asked for.
69 *
70 * Doesn't have to be accurate, i.e. may have races.
71 */
72unsigned int kobjsize(const void *objp)
73{
74 struct page *page;
75
76 /*
77 * If the object we have should not have ksize performed on it,
78 * return size of 0
79 */
80 if (!objp || !virt_addr_valid(objp))
81 return 0;
82
83 page = virt_to_head_page(objp);
84
85 /*
86 * If the allocator sets PageSlab, we know the pointer came from
87 * kmalloc().
88 */
89 if (PageSlab(page))
90 return ksize(objp);
91
92 /*
93 * If it's not a compound page, see if we have a matching VMA
94 * region. This test is intentionally done in reverse order,
95 * so if there's no VMA, we still fall through and hand back
96 * PAGE_SIZE for 0-order pages.
97 */
98 if (!PageCompound(page)) {
99 struct vm_area_struct *vma;
100
101 vma = find_vma(current->mm, (unsigned long)objp);
102 if (vma)
103 return vma->vm_end - vma->vm_start;
104 }
105
106 /*
107 * The ksize() function is only guaranteed to work for pointers
108 * returned by kmalloc(). So handle arbitrary pointers here.
109 */
110 return PAGE_SIZE << compound_order(page);
111}
112
113static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
114 unsigned long start, unsigned long nr_pages,
115 unsigned int foll_flags, struct page **pages,
116 struct vm_area_struct **vmas, int *nonblocking)
117{
118 struct vm_area_struct *vma;
119 unsigned long vm_flags;
120 int i;
121
122 /* calculate required read or write permissions.
123 * If FOLL_FORCE is set, we only require the "MAY" flags.
124 */
125 vm_flags = (foll_flags & FOLL_WRITE) ?
126 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
127 vm_flags &= (foll_flags & FOLL_FORCE) ?
128 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
129
130 for (i = 0; i < nr_pages; i++) {
131 vma = find_vma(mm, start);
132 if (!vma)
133 goto finish_or_fault;
134
135 /* protect what we can, including chardevs */
136 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
137 !(vm_flags & vma->vm_flags))
138 goto finish_or_fault;
139
140 if (pages) {
141 pages[i] = virt_to_page(start);
142 if (pages[i])
143 get_page(pages[i]);
144 }
145 if (vmas)
146 vmas[i] = vma;
147 start = (start + PAGE_SIZE) & PAGE_MASK;
148 }
149
150 return i;
151
152finish_or_fault:
153 return i ? : -EFAULT;
154}
155
156/*
157 * get a list of pages in an address range belonging to the specified process
158 * and indicate the VMA that covers each page
159 * - this is potentially dodgy as we may end incrementing the page count of a
160 * slab page or a secondary page from a compound page
161 * - don't permit access to VMAs that don't support it, such as I/O mappings
162 */
163long get_user_pages(unsigned long start, unsigned long nr_pages,
164 unsigned int gup_flags, struct page **pages,
165 struct vm_area_struct **vmas)
166{
167 return __get_user_pages(current, current->mm, start, nr_pages,
168 gup_flags, pages, vmas, NULL);
169}
170EXPORT_SYMBOL(get_user_pages);
171
172long get_user_pages_locked(unsigned long start, unsigned long nr_pages,
173 unsigned int gup_flags, struct page **pages,
174 int *locked)
175{
176 return get_user_pages(start, nr_pages, gup_flags, pages, NULL);
177}
178EXPORT_SYMBOL(get_user_pages_locked);
179
180static long __get_user_pages_unlocked(struct task_struct *tsk,
181 struct mm_struct *mm, unsigned long start,
182 unsigned long nr_pages, struct page **pages,
183 unsigned int gup_flags)
184{
185 long ret;
186 down_read(&mm->mmap_sem);
187 ret = __get_user_pages(tsk, mm, start, nr_pages, gup_flags, pages,
188 NULL, NULL);
189 up_read(&mm->mmap_sem);
190 return ret;
191}
192
193long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,
194 struct page **pages, unsigned int gup_flags)
195{
196 return __get_user_pages_unlocked(current, current->mm, start, nr_pages,
197 pages, gup_flags);
198}
199EXPORT_SYMBOL(get_user_pages_unlocked);
200
201/**
202 * follow_pfn - look up PFN at a user virtual address
203 * @vma: memory mapping
204 * @address: user virtual address
205 * @pfn: location to store found PFN
206 *
207 * Only IO mappings and raw PFN mappings are allowed.
208 *
209 * Returns zero and the pfn at @pfn on success, -ve otherwise.
210 */
211int follow_pfn(struct vm_area_struct *vma, unsigned long address,
212 unsigned long *pfn)
213{
214 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
215 return -EINVAL;
216
217 *pfn = address >> PAGE_SHIFT;
218 return 0;
219}
220EXPORT_SYMBOL(follow_pfn);
221
222LIST_HEAD(vmap_area_list);
223
224void vfree(const void *addr)
225{
226 kfree(addr);
227}
228EXPORT_SYMBOL(vfree);
229
230void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
231{
232 /*
233 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
234 * returns only a logical address.
235 */
236 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
237}
238EXPORT_SYMBOL(__vmalloc);
239
240void *__vmalloc_node_flags(unsigned long size, int node, gfp_t flags)
241{
242 return __vmalloc(size, flags, PAGE_KERNEL);
243}
244
245void *vmalloc_user(unsigned long size)
246{
247 void *ret;
248
249 ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
250 if (ret) {
251 struct vm_area_struct *vma;
252
253 down_write(¤t->mm->mmap_sem);
254 vma = find_vma(current->mm, (unsigned long)ret);
255 if (vma)
256 vma->vm_flags |= VM_USERMAP;
257 up_write(¤t->mm->mmap_sem);
258 }
259
260 return ret;
261}
262EXPORT_SYMBOL(vmalloc_user);
263
264struct page *vmalloc_to_page(const void *addr)
265{
266 return virt_to_page(addr);
267}
268EXPORT_SYMBOL(vmalloc_to_page);
269
270unsigned long vmalloc_to_pfn(const void *addr)
271{
272 return page_to_pfn(virt_to_page(addr));
273}
274EXPORT_SYMBOL(vmalloc_to_pfn);
275
276long vread(char *buf, char *addr, unsigned long count)
277{
278 /* Don't allow overflow */
279 if ((unsigned long) buf + count < count)
280 count = -(unsigned long) buf;
281
282 memcpy(buf, addr, count);
283 return count;
284}
285
286long vwrite(char *buf, char *addr, unsigned long count)
287{
288 /* Don't allow overflow */
289 if ((unsigned long) addr + count < count)
290 count = -(unsigned long) addr;
291
292 memcpy(addr, buf, count);
293 return count;
294}
295
296/*
297 * vmalloc - allocate virtually contiguous memory
298 *
299 * @size: allocation size
300 *
301 * Allocate enough pages to cover @size from the page level
302 * allocator and map them into contiguous kernel virtual space.
303 *
304 * For tight control over page level allocator and protection flags
305 * use __vmalloc() instead.
306 */
307void *vmalloc(unsigned long size)
308{
309 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
310}
311EXPORT_SYMBOL(vmalloc);
312
313/*
314 * vzalloc - allocate virtually contiguous memory with zero fill
315 *
316 * @size: allocation size
317 *
318 * Allocate enough pages to cover @size from the page level
319 * allocator and map them into contiguous kernel virtual space.
320 * The memory allocated is set to zero.
321 *
322 * For tight control over page level allocator and protection flags
323 * use __vmalloc() instead.
324 */
325void *vzalloc(unsigned long size)
326{
327 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
328 PAGE_KERNEL);
329}
330EXPORT_SYMBOL(vzalloc);
331
332/**
333 * vmalloc_node - allocate memory on a specific node
334 * @size: allocation size
335 * @node: numa node
336 *
337 * Allocate enough pages to cover @size from the page level
338 * allocator and map them into contiguous kernel virtual space.
339 *
340 * For tight control over page level allocator and protection flags
341 * use __vmalloc() instead.
342 */
343void *vmalloc_node(unsigned long size, int node)
344{
345 return vmalloc(size);
346}
347EXPORT_SYMBOL(vmalloc_node);
348
349/**
350 * vzalloc_node - allocate memory on a specific node with zero fill
351 * @size: allocation size
352 * @node: numa node
353 *
354 * Allocate enough pages to cover @size from the page level
355 * allocator and map them into contiguous kernel virtual space.
356 * The memory allocated is set to zero.
357 *
358 * For tight control over page level allocator and protection flags
359 * use __vmalloc() instead.
360 */
361void *vzalloc_node(unsigned long size, int node)
362{
363 return vzalloc(size);
364}
365EXPORT_SYMBOL(vzalloc_node);
366
367#ifndef PAGE_KERNEL_EXEC
368# define PAGE_KERNEL_EXEC PAGE_KERNEL
369#endif
370
371/**
372 * vmalloc_exec - allocate virtually contiguous, executable memory
373 * @size: allocation size
374 *
375 * Kernel-internal function to allocate enough pages to cover @size
376 * the page level allocator and map them into contiguous and
377 * executable kernel virtual space.
378 *
379 * For tight control over page level allocator and protection flags
380 * use __vmalloc() instead.
381 */
382
383void *vmalloc_exec(unsigned long size)
384{
385 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
386}
387
388/**
389 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
390 * @size: allocation size
391 *
392 * Allocate enough 32bit PA addressable pages to cover @size from the
393 * page level allocator and map them into contiguous kernel virtual space.
394 */
395void *vmalloc_32(unsigned long size)
396{
397 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
398}
399EXPORT_SYMBOL(vmalloc_32);
400
401/**
402 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
403 * @size: allocation size
404 *
405 * The resulting memory area is 32bit addressable and zeroed so it can be
406 * mapped to userspace without leaking data.
407 *
408 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
409 * remap_vmalloc_range() are permissible.
410 */
411void *vmalloc_32_user(unsigned long size)
412{
413 /*
414 * We'll have to sort out the ZONE_DMA bits for 64-bit,
415 * but for now this can simply use vmalloc_user() directly.
416 */
417 return vmalloc_user(size);
418}
419EXPORT_SYMBOL(vmalloc_32_user);
420
421void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
422{
423 BUG();
424 return NULL;
425}
426EXPORT_SYMBOL(vmap);
427
428void vunmap(const void *addr)
429{
430 BUG();
431}
432EXPORT_SYMBOL(vunmap);
433
434void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
435{
436 BUG();
437 return NULL;
438}
439EXPORT_SYMBOL(vm_map_ram);
440
441void vm_unmap_ram(const void *mem, unsigned int count)
442{
443 BUG();
444}
445EXPORT_SYMBOL(vm_unmap_ram);
446
447void vm_unmap_aliases(void)
448{
449}
450EXPORT_SYMBOL_GPL(vm_unmap_aliases);
451
452/*
453 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
454 * have one.
455 */
456void __weak vmalloc_sync_all(void)
457{
458}
459
460struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
461{
462 BUG();
463 return NULL;
464}
465EXPORT_SYMBOL_GPL(alloc_vm_area);
466
467void free_vm_area(struct vm_struct *area)
468{
469 BUG();
470}
471EXPORT_SYMBOL_GPL(free_vm_area);
472
473int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
474 struct page *page)
475{
476 return -EINVAL;
477}
478EXPORT_SYMBOL(vm_insert_page);
479
480/*
481 * sys_brk() for the most part doesn't need the global kernel
482 * lock, except when an application is doing something nasty
483 * like trying to un-brk an area that has already been mapped
484 * to a regular file. in this case, the unmapping will need
485 * to invoke file system routines that need the global lock.
486 */
487SYSCALL_DEFINE1(brk, unsigned long, brk)
488{
489 struct mm_struct *mm = current->mm;
490
491 if (brk < mm->start_brk || brk > mm->context.end_brk)
492 return mm->brk;
493
494 if (mm->brk == brk)
495 return mm->brk;
496
497 /*
498 * Always allow shrinking brk
499 */
500 if (brk <= mm->brk) {
501 mm->brk = brk;
502 return brk;
503 }
504
505 /*
506 * Ok, looks good - let it rip.
507 */
508 flush_icache_range(mm->brk, brk);
509 return mm->brk = brk;
510}
511
512/*
513 * initialise the percpu counter for VM and region record slabs
514 */
515void __init mmap_init(void)
516{
517 int ret;
518
519 ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
520 VM_BUG_ON(ret);
521 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
522}
523
524/*
525 * validate the region tree
526 * - the caller must hold the region lock
527 */
528#ifdef CONFIG_DEBUG_NOMMU_REGIONS
529static noinline void validate_nommu_regions(void)
530{
531 struct vm_region *region, *last;
532 struct rb_node *p, *lastp;
533
534 lastp = rb_first(&nommu_region_tree);
535 if (!lastp)
536 return;
537
538 last = rb_entry(lastp, struct vm_region, vm_rb);
539 BUG_ON(last->vm_end <= last->vm_start);
540 BUG_ON(last->vm_top < last->vm_end);
541
542 while ((p = rb_next(lastp))) {
543 region = rb_entry(p, struct vm_region, vm_rb);
544 last = rb_entry(lastp, struct vm_region, vm_rb);
545
546 BUG_ON(region->vm_end <= region->vm_start);
547 BUG_ON(region->vm_top < region->vm_end);
548 BUG_ON(region->vm_start < last->vm_top);
549
550 lastp = p;
551 }
552}
553#else
554static void validate_nommu_regions(void)
555{
556}
557#endif
558
559/*
560 * add a region into the global tree
561 */
562static void add_nommu_region(struct vm_region *region)
563{
564 struct vm_region *pregion;
565 struct rb_node **p, *parent;
566
567 validate_nommu_regions();
568
569 parent = NULL;
570 p = &nommu_region_tree.rb_node;
571 while (*p) {
572 parent = *p;
573 pregion = rb_entry(parent, struct vm_region, vm_rb);
574 if (region->vm_start < pregion->vm_start)
575 p = &(*p)->rb_left;
576 else if (region->vm_start > pregion->vm_start)
577 p = &(*p)->rb_right;
578 else if (pregion == region)
579 return;
580 else
581 BUG();
582 }
583
584 rb_link_node(®ion->vm_rb, parent, p);
585 rb_insert_color(®ion->vm_rb, &nommu_region_tree);
586
587 validate_nommu_regions();
588}
589
590/*
591 * delete a region from the global tree
592 */
593static void delete_nommu_region(struct vm_region *region)
594{
595 BUG_ON(!nommu_region_tree.rb_node);
596
597 validate_nommu_regions();
598 rb_erase(®ion->vm_rb, &nommu_region_tree);
599 validate_nommu_regions();
600}
601
602/*
603 * free a contiguous series of pages
604 */
605static void free_page_series(unsigned long from, unsigned long to)
606{
607 for (; from < to; from += PAGE_SIZE) {
608 struct page *page = virt_to_page(from);
609
610 atomic_long_dec(&mmap_pages_allocated);
611 put_page(page);
612 }
613}
614
615/*
616 * release a reference to a region
617 * - the caller must hold the region semaphore for writing, which this releases
618 * - the region may not have been added to the tree yet, in which case vm_top
619 * will equal vm_start
620 */
621static void __put_nommu_region(struct vm_region *region)
622 __releases(nommu_region_sem)
623{
624 BUG_ON(!nommu_region_tree.rb_node);
625
626 if (--region->vm_usage == 0) {
627 if (region->vm_top > region->vm_start)
628 delete_nommu_region(region);
629 up_write(&nommu_region_sem);
630
631 if (region->vm_file)
632 fput(region->vm_file);
633
634 /* IO memory and memory shared directly out of the pagecache
635 * from ramfs/tmpfs mustn't be released here */
636 if (region->vm_flags & VM_MAPPED_COPY)
637 free_page_series(region->vm_start, region->vm_top);
638 kmem_cache_free(vm_region_jar, region);
639 } else {
640 up_write(&nommu_region_sem);
641 }
642}
643
644/*
645 * release a reference to a region
646 */
647static void put_nommu_region(struct vm_region *region)
648{
649 down_write(&nommu_region_sem);
650 __put_nommu_region(region);
651}
652
653/*
654 * add a VMA into a process's mm_struct in the appropriate place in the list
655 * and tree and add to the address space's page tree also if not an anonymous
656 * page
657 * - should be called with mm->mmap_sem held writelocked
658 */
659static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
660{
661 struct vm_area_struct *pvma, *prev;
662 struct address_space *mapping;
663 struct rb_node **p, *parent, *rb_prev;
664
665 BUG_ON(!vma->vm_region);
666
667 mm->map_count++;
668 vma->vm_mm = mm;
669
670 /* add the VMA to the mapping */
671 if (vma->vm_file) {
672 mapping = vma->vm_file->f_mapping;
673
674 i_mmap_lock_write(mapping);
675 flush_dcache_mmap_lock(mapping);
676 vma_interval_tree_insert(vma, &mapping->i_mmap);
677 flush_dcache_mmap_unlock(mapping);
678 i_mmap_unlock_write(mapping);
679 }
680
681 /* add the VMA to the tree */
682 parent = rb_prev = NULL;
683 p = &mm->mm_rb.rb_node;
684 while (*p) {
685 parent = *p;
686 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
687
688 /* sort by: start addr, end addr, VMA struct addr in that order
689 * (the latter is necessary as we may get identical VMAs) */
690 if (vma->vm_start < pvma->vm_start)
691 p = &(*p)->rb_left;
692 else if (vma->vm_start > pvma->vm_start) {
693 rb_prev = parent;
694 p = &(*p)->rb_right;
695 } else if (vma->vm_end < pvma->vm_end)
696 p = &(*p)->rb_left;
697 else if (vma->vm_end > pvma->vm_end) {
698 rb_prev = parent;
699 p = &(*p)->rb_right;
700 } else if (vma < pvma)
701 p = &(*p)->rb_left;
702 else if (vma > pvma) {
703 rb_prev = parent;
704 p = &(*p)->rb_right;
705 } else
706 BUG();
707 }
708
709 rb_link_node(&vma->vm_rb, parent, p);
710 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
711
712 /* add VMA to the VMA list also */
713 prev = NULL;
714 if (rb_prev)
715 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
716
717 __vma_link_list(mm, vma, prev, parent);
718}
719
720/*
721 * delete a VMA from its owning mm_struct and address space
722 */
723static void delete_vma_from_mm(struct vm_area_struct *vma)
724{
725 int i;
726 struct address_space *mapping;
727 struct mm_struct *mm = vma->vm_mm;
728 struct task_struct *curr = current;
729
730 mm->map_count--;
731 for (i = 0; i < VMACACHE_SIZE; i++) {
732 /* if the vma is cached, invalidate the entire cache */
733 if (curr->vmacache.vmas[i] == vma) {
734 vmacache_invalidate(mm);
735 break;
736 }
737 }
738
739 /* remove the VMA from the mapping */
740 if (vma->vm_file) {
741 mapping = vma->vm_file->f_mapping;
742
743 i_mmap_lock_write(mapping);
744 flush_dcache_mmap_lock(mapping);
745 vma_interval_tree_remove(vma, &mapping->i_mmap);
746 flush_dcache_mmap_unlock(mapping);
747 i_mmap_unlock_write(mapping);
748 }
749
750 /* remove from the MM's tree and list */
751 rb_erase(&vma->vm_rb, &mm->mm_rb);
752
753 if (vma->vm_prev)
754 vma->vm_prev->vm_next = vma->vm_next;
755 else
756 mm->mmap = vma->vm_next;
757
758 if (vma->vm_next)
759 vma->vm_next->vm_prev = vma->vm_prev;
760}
761
762/*
763 * destroy a VMA record
764 */
765static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
766{
767 if (vma->vm_ops && vma->vm_ops->close)
768 vma->vm_ops->close(vma);
769 if (vma->vm_file)
770 fput(vma->vm_file);
771 put_nommu_region(vma->vm_region);
772 kmem_cache_free(vm_area_cachep, vma);
773}
774
775/*
776 * look up the first VMA in which addr resides, NULL if none
777 * - should be called with mm->mmap_sem at least held readlocked
778 */
779struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
780{
781 struct vm_area_struct *vma;
782
783 /* check the cache first */
784 vma = vmacache_find(mm, addr);
785 if (likely(vma))
786 return vma;
787
788 /* trawl the list (there may be multiple mappings in which addr
789 * resides) */
790 for (vma = mm->mmap; vma; vma = vma->vm_next) {
791 if (vma->vm_start > addr)
792 return NULL;
793 if (vma->vm_end > addr) {
794 vmacache_update(addr, vma);
795 return vma;
796 }
797 }
798
799 return NULL;
800}
801EXPORT_SYMBOL(find_vma);
802
803/*
804 * find a VMA
805 * - we don't extend stack VMAs under NOMMU conditions
806 */
807struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
808{
809 return find_vma(mm, addr);
810}
811
812/*
813 * expand a stack to a given address
814 * - not supported under NOMMU conditions
815 */
816int expand_stack(struct vm_area_struct *vma, unsigned long address)
817{
818 return -ENOMEM;
819}
820
821/*
822 * look up the first VMA exactly that exactly matches addr
823 * - should be called with mm->mmap_sem at least held readlocked
824 */
825static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
826 unsigned long addr,
827 unsigned long len)
828{
829 struct vm_area_struct *vma;
830 unsigned long end = addr + len;
831
832 /* check the cache first */
833 vma = vmacache_find_exact(mm, addr, end);
834 if (vma)
835 return vma;
836
837 /* trawl the list (there may be multiple mappings in which addr
838 * resides) */
839 for (vma = mm->mmap; vma; vma = vma->vm_next) {
840 if (vma->vm_start < addr)
841 continue;
842 if (vma->vm_start > addr)
843 return NULL;
844 if (vma->vm_end == end) {
845 vmacache_update(addr, vma);
846 return vma;
847 }
848 }
849
850 return NULL;
851}
852
853/*
854 * determine whether a mapping should be permitted and, if so, what sort of
855 * mapping we're capable of supporting
856 */
857static int validate_mmap_request(struct file *file,
858 unsigned long addr,
859 unsigned long len,
860 unsigned long prot,
861 unsigned long flags,
862 unsigned long pgoff,
863 unsigned long *_capabilities)
864{
865 unsigned long capabilities, rlen;
866 int ret;
867
868 /* do the simple checks first */
869 if (flags & MAP_FIXED)
870 return -EINVAL;
871
872 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
873 (flags & MAP_TYPE) != MAP_SHARED)
874 return -EINVAL;
875
876 if (!len)
877 return -EINVAL;
878
879 /* Careful about overflows.. */
880 rlen = PAGE_ALIGN(len);
881 if (!rlen || rlen > TASK_SIZE)
882 return -ENOMEM;
883
884 /* offset overflow? */
885 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
886 return -EOVERFLOW;
887
888 if (file) {
889 /* files must support mmap */
890 if (!file->f_op->mmap)
891 return -ENODEV;
892
893 /* work out if what we've got could possibly be shared
894 * - we support chardevs that provide their own "memory"
895 * - we support files/blockdevs that are memory backed
896 */
897 if (file->f_op->mmap_capabilities) {
898 capabilities = file->f_op->mmap_capabilities(file);
899 } else {
900 /* no explicit capabilities set, so assume some
901 * defaults */
902 switch (file_inode(file)->i_mode & S_IFMT) {
903 case S_IFREG:
904 case S_IFBLK:
905 capabilities = NOMMU_MAP_COPY;
906 break;
907
908 case S_IFCHR:
909 capabilities =
910 NOMMU_MAP_DIRECT |
911 NOMMU_MAP_READ |
912 NOMMU_MAP_WRITE;
913 break;
914
915 default:
916 return -EINVAL;
917 }
918 }
919
920 /* eliminate any capabilities that we can't support on this
921 * device */
922 if (!file->f_op->get_unmapped_area)
923 capabilities &= ~NOMMU_MAP_DIRECT;
924 if (!(file->f_mode & FMODE_CAN_READ))
925 capabilities &= ~NOMMU_MAP_COPY;
926
927 /* The file shall have been opened with read permission. */
928 if (!(file->f_mode & FMODE_READ))
929 return -EACCES;
930
931 if (flags & MAP_SHARED) {
932 /* do checks for writing, appending and locking */
933 if ((prot & PROT_WRITE) &&
934 !(file->f_mode & FMODE_WRITE))
935 return -EACCES;
936
937 if (IS_APPEND(file_inode(file)) &&
938 (file->f_mode & FMODE_WRITE))
939 return -EACCES;
940
941 if (locks_verify_locked(file))
942 return -EAGAIN;
943
944 if (!(capabilities & NOMMU_MAP_DIRECT))
945 return -ENODEV;
946
947 /* we mustn't privatise shared mappings */
948 capabilities &= ~NOMMU_MAP_COPY;
949 } else {
950 /* we're going to read the file into private memory we
951 * allocate */
952 if (!(capabilities & NOMMU_MAP_COPY))
953 return -ENODEV;
954
955 /* we don't permit a private writable mapping to be
956 * shared with the backing device */
957 if (prot & PROT_WRITE)
958 capabilities &= ~NOMMU_MAP_DIRECT;
959 }
960
961 if (capabilities & NOMMU_MAP_DIRECT) {
962 if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
963 ((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
964 ((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
965 ) {
966 capabilities &= ~NOMMU_MAP_DIRECT;
967 if (flags & MAP_SHARED) {
968 pr_warn("MAP_SHARED not completely supported on !MMU\n");
969 return -EINVAL;
970 }
971 }
972 }
973
974 /* handle executable mappings and implied executable
975 * mappings */
976 if (path_noexec(&file->f_path)) {
977 if (prot & PROT_EXEC)
978 return -EPERM;
979 } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
980 /* handle implication of PROT_EXEC by PROT_READ */
981 if (current->personality & READ_IMPLIES_EXEC) {
982 if (capabilities & NOMMU_MAP_EXEC)
983 prot |= PROT_EXEC;
984 }
985 } else if ((prot & PROT_READ) &&
986 (prot & PROT_EXEC) &&
987 !(capabilities & NOMMU_MAP_EXEC)
988 ) {
989 /* backing file is not executable, try to copy */
990 capabilities &= ~NOMMU_MAP_DIRECT;
991 }
992 } else {
993 /* anonymous mappings are always memory backed and can be
994 * privately mapped
995 */
996 capabilities = NOMMU_MAP_COPY;
997
998 /* handle PROT_EXEC implication by PROT_READ */
999 if ((prot & PROT_READ) &&
1000 (current->personality & READ_IMPLIES_EXEC))
1001 prot |= PROT_EXEC;
1002 }
1003
1004 /* allow the security API to have its say */
1005 ret = security_mmap_addr(addr);
1006 if (ret < 0)
1007 return ret;
1008
1009 /* looks okay */
1010 *_capabilities = capabilities;
1011 return 0;
1012}
1013
1014/*
1015 * we've determined that we can make the mapping, now translate what we
1016 * now know into VMA flags
1017 */
1018static unsigned long determine_vm_flags(struct file *file,
1019 unsigned long prot,
1020 unsigned long flags,
1021 unsigned long capabilities)
1022{
1023 unsigned long vm_flags;
1024
1025 vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
1026 /* vm_flags |= mm->def_flags; */
1027
1028 if (!(capabilities & NOMMU_MAP_DIRECT)) {
1029 /* attempt to share read-only copies of mapped file chunks */
1030 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1031 if (file && !(prot & PROT_WRITE))
1032 vm_flags |= VM_MAYSHARE;
1033 } else {
1034 /* overlay a shareable mapping on the backing device or inode
1035 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1036 * romfs/cramfs */
1037 vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS);
1038 if (flags & MAP_SHARED)
1039 vm_flags |= VM_SHARED;
1040 }
1041
1042 /* refuse to let anyone share private mappings with this process if
1043 * it's being traced - otherwise breakpoints set in it may interfere
1044 * with another untraced process
1045 */
1046 if ((flags & MAP_PRIVATE) && current->ptrace)
1047 vm_flags &= ~VM_MAYSHARE;
1048
1049 return vm_flags;
1050}
1051
1052/*
1053 * set up a shared mapping on a file (the driver or filesystem provides and
1054 * pins the storage)
1055 */
1056static int do_mmap_shared_file(struct vm_area_struct *vma)
1057{
1058 int ret;
1059
1060 ret = call_mmap(vma->vm_file, vma);
1061 if (ret == 0) {
1062 vma->vm_region->vm_top = vma->vm_region->vm_end;
1063 return 0;
1064 }
1065 if (ret != -ENOSYS)
1066 return ret;
1067
1068 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1069 * opposed to tried but failed) so we can only give a suitable error as
1070 * it's not possible to make a private copy if MAP_SHARED was given */
1071 return -ENODEV;
1072}
1073
1074/*
1075 * set up a private mapping or an anonymous shared mapping
1076 */
1077static int do_mmap_private(struct vm_area_struct *vma,
1078 struct vm_region *region,
1079 unsigned long len,
1080 unsigned long capabilities)
1081{
1082 unsigned long total, point;
1083 void *base;
1084 int ret, order;
1085
1086 /* invoke the file's mapping function so that it can keep track of
1087 * shared mappings on devices or memory
1088 * - VM_MAYSHARE will be set if it may attempt to share
1089 */
1090 if (capabilities & NOMMU_MAP_DIRECT) {
1091 ret = call_mmap(vma->vm_file, vma);
1092 if (ret == 0) {
1093 /* shouldn't return success if we're not sharing */
1094 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1095 vma->vm_region->vm_top = vma->vm_region->vm_end;
1096 return 0;
1097 }
1098 if (ret != -ENOSYS)
1099 return ret;
1100
1101 /* getting an ENOSYS error indicates that direct mmap isn't
1102 * possible (as opposed to tried but failed) so we'll try to
1103 * make a private copy of the data and map that instead */
1104 }
1105
1106
1107 /* allocate some memory to hold the mapping
1108 * - note that this may not return a page-aligned address if the object
1109 * we're allocating is smaller than a page
1110 */
1111 order = get_order(len);
1112 total = 1 << order;
1113 point = len >> PAGE_SHIFT;
1114
1115 /* we don't want to allocate a power-of-2 sized page set */
1116 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages)
1117 total = point;
1118
1119 base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
1120 if (!base)
1121 goto enomem;
1122
1123 atomic_long_add(total, &mmap_pages_allocated);
1124
1125 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1126 region->vm_start = (unsigned long) base;
1127 region->vm_end = region->vm_start + len;
1128 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1129
1130 vma->vm_start = region->vm_start;
1131 vma->vm_end = region->vm_start + len;
1132
1133 if (vma->vm_file) {
1134 /* read the contents of a file into the copy */
1135 loff_t fpos;
1136
1137 fpos = vma->vm_pgoff;
1138 fpos <<= PAGE_SHIFT;
1139
1140 ret = kernel_read(vma->vm_file, base, len, &fpos);
1141 if (ret < 0)
1142 goto error_free;
1143
1144 /* clear the last little bit */
1145 if (ret < len)
1146 memset(base + ret, 0, len - ret);
1147
1148 }
1149
1150 return 0;
1151
1152error_free:
1153 free_page_series(region->vm_start, region->vm_top);
1154 region->vm_start = vma->vm_start = 0;
1155 region->vm_end = vma->vm_end = 0;
1156 region->vm_top = 0;
1157 return ret;
1158
1159enomem:
1160 pr_err("Allocation of length %lu from process %d (%s) failed\n",
1161 len, current->pid, current->comm);
1162 show_free_areas(0, NULL);
1163 return -ENOMEM;
1164}
1165
1166/*
1167 * handle mapping creation for uClinux
1168 */
1169unsigned long do_mmap(struct file *file,
1170 unsigned long addr,
1171 unsigned long len,
1172 unsigned long prot,
1173 unsigned long flags,
1174 vm_flags_t vm_flags,
1175 unsigned long pgoff,
1176 unsigned long *populate,
1177 struct list_head *uf)
1178{
1179 struct vm_area_struct *vma;
1180 struct vm_region *region;
1181 struct rb_node *rb;
1182 unsigned long capabilities, result;
1183 int ret;
1184
1185 *populate = 0;
1186
1187 /* decide whether we should attempt the mapping, and if so what sort of
1188 * mapping */
1189 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1190 &capabilities);
1191 if (ret < 0)
1192 return ret;
1193
1194 /* we ignore the address hint */
1195 addr = 0;
1196 len = PAGE_ALIGN(len);
1197
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);
1201
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;
1206
1207 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1208 if (!vma)
1209 goto error_getting_vma;
1210
1211 region->vm_usage = 1;
1212 region->vm_flags = vm_flags;
1213 region->vm_pgoff = pgoff;
1214
1215 INIT_LIST_HEAD(&vma->anon_vma_chain);
1216 vma->vm_flags = vm_flags;
1217 vma->vm_pgoff = pgoff;
1218
1219 if (file) {
1220 region->vm_file = get_file(file);
1221 vma->vm_file = get_file(file);
1222 }
1223
1224 down_write(&nommu_region_sem);
1225
1226 /* if we want to share, we need to check for regions created by other
1227 * mmap() calls that overlap with our proposed mapping
1228 * - we can only share with a superset match on most regular files
1229 * - shared mappings on character devices and memory backed files are
1230 * permitted to overlap inexactly as far as we are concerned for in
1231 * these cases, sharing is handled in the driver or filesystem rather
1232 * than here
1233 */
1234 if (vm_flags & VM_MAYSHARE) {
1235 struct vm_region *pregion;
1236 unsigned long pglen, rpglen, pgend, rpgend, start;
1237
1238 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1239 pgend = pgoff + pglen;
1240
1241 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1242 pregion = rb_entry(rb, struct vm_region, vm_rb);
1243
1244 if (!(pregion->vm_flags & VM_MAYSHARE))
1245 continue;
1246
1247 /* search for overlapping mappings on the same file */
1248 if (file_inode(pregion->vm_file) !=
1249 file_inode(file))
1250 continue;
1251
1252 if (pregion->vm_pgoff >= pgend)
1253 continue;
1254
1255 rpglen = pregion->vm_end - pregion->vm_start;
1256 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1257 rpgend = pregion->vm_pgoff + rpglen;
1258 if (pgoff >= rpgend)
1259 continue;
1260
1261 /* handle inexactly overlapping matches between
1262 * mappings */
1263 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1264 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1265 /* new mapping is not a subset of the region */
1266 if (!(capabilities & NOMMU_MAP_DIRECT))
1267 goto sharing_violation;
1268 continue;
1269 }
1270
1271 /* we've found a region we can share */
1272 pregion->vm_usage++;
1273 vma->vm_region = pregion;
1274 start = pregion->vm_start;
1275 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1276 vma->vm_start = start;
1277 vma->vm_end = start + len;
1278
1279 if (pregion->vm_flags & VM_MAPPED_COPY)
1280 vma->vm_flags |= VM_MAPPED_COPY;
1281 else {
1282 ret = do_mmap_shared_file(vma);
1283 if (ret < 0) {
1284 vma->vm_region = NULL;
1285 vma->vm_start = 0;
1286 vma->vm_end = 0;
1287 pregion->vm_usage--;
1288 pregion = NULL;
1289 goto error_just_free;
1290 }
1291 }
1292 fput(region->vm_file);
1293 kmem_cache_free(vm_region_jar, region);
1294 region = pregion;
1295 result = start;
1296 goto share;
1297 }
1298
1299 /* obtain the address at which to make a shared mapping
1300 * - this is the hook for quasi-memory character devices to
1301 * tell us the location of a shared mapping
1302 */
1303 if (capabilities & NOMMU_MAP_DIRECT) {
1304 addr = file->f_op->get_unmapped_area(file, addr, len,
1305 pgoff, flags);
1306 if (IS_ERR_VALUE(addr)) {
1307 ret = addr;
1308 if (ret != -ENOSYS)
1309 goto error_just_free;
1310
1311 /* the driver refused to tell us where to site
1312 * the mapping so we'll have to attempt to copy
1313 * it */
1314 ret = -ENODEV;
1315 if (!(capabilities & NOMMU_MAP_COPY))
1316 goto error_just_free;
1317
1318 capabilities &= ~NOMMU_MAP_DIRECT;
1319 } else {
1320 vma->vm_start = region->vm_start = addr;
1321 vma->vm_end = region->vm_end = addr + len;
1322 }
1323 }
1324 }
1325
1326 vma->vm_region = region;
1327
1328 /* set up the mapping
1329 * - the region is filled in if NOMMU_MAP_DIRECT is still set
1330 */
1331 if (file && vma->vm_flags & VM_SHARED)
1332 ret = do_mmap_shared_file(vma);
1333 else
1334 ret = do_mmap_private(vma, region, len, capabilities);
1335 if (ret < 0)
1336 goto error_just_free;
1337 add_nommu_region(region);
1338
1339 /* clear anonymous mappings that don't ask for uninitialized data */
1340 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1341 memset((void *)region->vm_start, 0,
1342 region->vm_end - region->vm_start);
1343
1344 /* okay... we have a mapping; now we have to register it */
1345 result = vma->vm_start;
1346
1347 current->mm->total_vm += len >> PAGE_SHIFT;
1348
1349share:
1350 add_vma_to_mm(current->mm, vma);
1351
1352 /* we flush the region from the icache only when the first executable
1353 * mapping of it is made */
1354 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1355 flush_icache_range(region->vm_start, region->vm_end);
1356 region->vm_icache_flushed = true;
1357 }
1358
1359 up_write(&nommu_region_sem);
1360
1361 return result;
1362
1363error_just_free:
1364 up_write(&nommu_region_sem);
1365error:
1366 if (region->vm_file)
1367 fput(region->vm_file);
1368 kmem_cache_free(vm_region_jar, region);
1369 if (vma->vm_file)
1370 fput(vma->vm_file);
1371 kmem_cache_free(vm_area_cachep, vma);
1372 return ret;
1373
1374sharing_violation:
1375 up_write(&nommu_region_sem);
1376 pr_warn("Attempt to share mismatched mappings\n");
1377 ret = -EINVAL;
1378 goto error;
1379
1380error_getting_vma:
1381 kmem_cache_free(vm_region_jar, region);
1382 pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
1383 len, current->pid);
1384 show_free_areas(0, NULL);
1385 return -ENOMEM;
1386
1387error_getting_region:
1388 pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
1389 len, current->pid);
1390 show_free_areas(0, NULL);
1391 return -ENOMEM;
1392}
1393
1394unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
1395 unsigned long prot, unsigned long flags,
1396 unsigned long fd, unsigned long pgoff)
1397{
1398 struct file *file = NULL;
1399 unsigned long retval = -EBADF;
1400
1401 audit_mmap_fd(fd, flags);
1402 if (!(flags & MAP_ANONYMOUS)) {
1403 file = fget(fd);
1404 if (!file)
1405 goto out;
1406 }
1407
1408 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1409
1410 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1411
1412 if (file)
1413 fput(file);
1414out:
1415 return retval;
1416}
1417
1418SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1419 unsigned long, prot, unsigned long, flags,
1420 unsigned long, fd, unsigned long, pgoff)
1421{
1422 return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
1423}
1424
1425#ifdef __ARCH_WANT_SYS_OLD_MMAP
1426struct mmap_arg_struct {
1427 unsigned long addr;
1428 unsigned long len;
1429 unsigned long prot;
1430 unsigned long flags;
1431 unsigned long fd;
1432 unsigned long offset;
1433};
1434
1435SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1436{
1437 struct mmap_arg_struct a;
1438
1439 if (copy_from_user(&a, arg, sizeof(a)))
1440 return -EFAULT;
1441 if (offset_in_page(a.offset))
1442 return -EINVAL;
1443
1444 return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1445 a.offset >> PAGE_SHIFT);
1446}
1447#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1448
1449/*
1450 * split a vma into two pieces at address 'addr', a new vma is allocated either
1451 * for the first part or the tail.
1452 */
1453int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1454 unsigned long addr, int new_below)
1455{
1456 struct vm_area_struct *new;
1457 struct vm_region *region;
1458 unsigned long npages;
1459
1460 /* we're only permitted to split anonymous regions (these should have
1461 * only a single usage on the region) */
1462 if (vma->vm_file)
1463 return -ENOMEM;
1464
1465 if (mm->map_count >= sysctl_max_map_count)
1466 return -ENOMEM;
1467
1468 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1469 if (!region)
1470 return -ENOMEM;
1471
1472 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1473 if (!new) {
1474 kmem_cache_free(vm_region_jar, region);
1475 return -ENOMEM;
1476 }
1477
1478 /* most fields are the same, copy all, and then fixup */
1479 *new = *vma;
1480 *region = *vma->vm_region;
1481 new->vm_region = region;
1482
1483 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1484
1485 if (new_below) {
1486 region->vm_top = region->vm_end = new->vm_end = addr;
1487 } else {
1488 region->vm_start = new->vm_start = addr;
1489 region->vm_pgoff = new->vm_pgoff += npages;
1490 }
1491
1492 if (new->vm_ops && new->vm_ops->open)
1493 new->vm_ops->open(new);
1494
1495 delete_vma_from_mm(vma);
1496 down_write(&nommu_region_sem);
1497 delete_nommu_region(vma->vm_region);
1498 if (new_below) {
1499 vma->vm_region->vm_start = vma->vm_start = addr;
1500 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1501 } else {
1502 vma->vm_region->vm_end = vma->vm_end = addr;
1503 vma->vm_region->vm_top = addr;
1504 }
1505 add_nommu_region(vma->vm_region);
1506 add_nommu_region(new->vm_region);
1507 up_write(&nommu_region_sem);
1508 add_vma_to_mm(mm, vma);
1509 add_vma_to_mm(mm, new);
1510 return 0;
1511}
1512
1513/*
1514 * shrink a VMA by removing the specified chunk from either the beginning or
1515 * the end
1516 */
1517static int shrink_vma(struct mm_struct *mm,
1518 struct vm_area_struct *vma,
1519 unsigned long from, unsigned long to)
1520{
1521 struct vm_region *region;
1522
1523 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1524 * and list */
1525 delete_vma_from_mm(vma);
1526 if (from > vma->vm_start)
1527 vma->vm_end = from;
1528 else
1529 vma->vm_start = to;
1530 add_vma_to_mm(mm, vma);
1531
1532 /* cut the backing region down to size */
1533 region = vma->vm_region;
1534 BUG_ON(region->vm_usage != 1);
1535
1536 down_write(&nommu_region_sem);
1537 delete_nommu_region(region);
1538 if (from > region->vm_start) {
1539 to = region->vm_top;
1540 region->vm_top = region->vm_end = from;
1541 } else {
1542 region->vm_start = to;
1543 }
1544 add_nommu_region(region);
1545 up_write(&nommu_region_sem);
1546
1547 free_page_series(from, to);
1548 return 0;
1549}
1550
1551/*
1552 * release a mapping
1553 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1554 * VMA, though it need not cover the whole VMA
1555 */
1556int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
1557{
1558 struct vm_area_struct *vma;
1559 unsigned long end;
1560 int ret;
1561
1562 len = PAGE_ALIGN(len);
1563 if (len == 0)
1564 return -EINVAL;
1565
1566 end = start + len;
1567
1568 /* find the first potentially overlapping VMA */
1569 vma = find_vma(mm, start);
1570 if (!vma) {
1571 static int limit;
1572 if (limit < 5) {
1573 pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
1574 current->pid, current->comm,
1575 start, start + len - 1);
1576 limit++;
1577 }
1578 return -EINVAL;
1579 }
1580
1581 /* we're allowed to split an anonymous VMA but not a file-backed one */
1582 if (vma->vm_file) {
1583 do {
1584 if (start > vma->vm_start)
1585 return -EINVAL;
1586 if (end == vma->vm_end)
1587 goto erase_whole_vma;
1588 vma = vma->vm_next;
1589 } while (vma);
1590 return -EINVAL;
1591 } else {
1592 /* the chunk must be a subset of the VMA found */
1593 if (start == vma->vm_start && end == vma->vm_end)
1594 goto erase_whole_vma;
1595 if (start < vma->vm_start || end > vma->vm_end)
1596 return -EINVAL;
1597 if (offset_in_page(start))
1598 return -EINVAL;
1599 if (end != vma->vm_end && offset_in_page(end))
1600 return -EINVAL;
1601 if (start != vma->vm_start && end != vma->vm_end) {
1602 ret = split_vma(mm, vma, start, 1);
1603 if (ret < 0)
1604 return ret;
1605 }
1606 return shrink_vma(mm, vma, start, end);
1607 }
1608
1609erase_whole_vma:
1610 delete_vma_from_mm(vma);
1611 delete_vma(mm, vma);
1612 return 0;
1613}
1614EXPORT_SYMBOL(do_munmap);
1615
1616int vm_munmap(unsigned long addr, size_t len)
1617{
1618 struct mm_struct *mm = current->mm;
1619 int ret;
1620
1621 down_write(&mm->mmap_sem);
1622 ret = do_munmap(mm, addr, len, NULL);
1623 up_write(&mm->mmap_sem);
1624 return ret;
1625}
1626EXPORT_SYMBOL(vm_munmap);
1627
1628SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1629{
1630 return vm_munmap(addr, len);
1631}
1632
1633/*
1634 * release all the mappings made in a process's VM space
1635 */
1636void exit_mmap(struct mm_struct *mm)
1637{
1638 struct vm_area_struct *vma;
1639
1640 if (!mm)
1641 return;
1642
1643 mm->total_vm = 0;
1644
1645 while ((vma = mm->mmap)) {
1646 mm->mmap = vma->vm_next;
1647 delete_vma_from_mm(vma);
1648 delete_vma(mm, vma);
1649 cond_resched();
1650 }
1651}
1652
1653int vm_brk(unsigned long addr, unsigned long len)
1654{
1655 return -ENOMEM;
1656}
1657
1658/*
1659 * expand (or shrink) an existing mapping, potentially moving it at the same
1660 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1661 *
1662 * under NOMMU conditions, we only permit changing a mapping's size, and only
1663 * as long as it stays within the region allocated by do_mmap_private() and the
1664 * block is not shareable
1665 *
1666 * MREMAP_FIXED is not supported under NOMMU conditions
1667 */
1668static unsigned long do_mremap(unsigned long addr,
1669 unsigned long old_len, unsigned long new_len,
1670 unsigned long flags, unsigned long new_addr)
1671{
1672 struct vm_area_struct *vma;
1673
1674 /* insanity checks first */
1675 old_len = PAGE_ALIGN(old_len);
1676 new_len = PAGE_ALIGN(new_len);
1677 if (old_len == 0 || new_len == 0)
1678 return (unsigned long) -EINVAL;
1679
1680 if (offset_in_page(addr))
1681 return -EINVAL;
1682
1683 if (flags & MREMAP_FIXED && new_addr != addr)
1684 return (unsigned long) -EINVAL;
1685
1686 vma = find_vma_exact(current->mm, addr, old_len);
1687 if (!vma)
1688 return (unsigned long) -EINVAL;
1689
1690 if (vma->vm_end != vma->vm_start + old_len)
1691 return (unsigned long) -EFAULT;
1692
1693 if (vma->vm_flags & VM_MAYSHARE)
1694 return (unsigned long) -EPERM;
1695
1696 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1697 return (unsigned long) -ENOMEM;
1698
1699 /* all checks complete - do it */
1700 vma->vm_end = vma->vm_start + new_len;
1701 return vma->vm_start;
1702}
1703
1704SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1705 unsigned long, new_len, unsigned long, flags,
1706 unsigned long, new_addr)
1707{
1708 unsigned long ret;
1709
1710 down_write(¤t->mm->mmap_sem);
1711 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1712 up_write(¤t->mm->mmap_sem);
1713 return ret;
1714}
1715
1716struct page *follow_page_mask(struct vm_area_struct *vma,
1717 unsigned long address, unsigned int flags,
1718 unsigned int *page_mask)
1719{
1720 *page_mask = 0;
1721 return NULL;
1722}
1723
1724int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1725 unsigned long pfn, unsigned long size, pgprot_t prot)
1726{
1727 if (addr != (pfn << PAGE_SHIFT))
1728 return -EINVAL;
1729
1730 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1731 return 0;
1732}
1733EXPORT_SYMBOL(remap_pfn_range);
1734
1735int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1736{
1737 unsigned long pfn = start >> PAGE_SHIFT;
1738 unsigned long vm_len = vma->vm_end - vma->vm_start;
1739
1740 pfn += vma->vm_pgoff;
1741 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1742}
1743EXPORT_SYMBOL(vm_iomap_memory);
1744
1745int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1746 unsigned long pgoff)
1747{
1748 unsigned int size = vma->vm_end - vma->vm_start;
1749
1750 if (!(vma->vm_flags & VM_USERMAP))
1751 return -EINVAL;
1752
1753 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1754 vma->vm_end = vma->vm_start + size;
1755
1756 return 0;
1757}
1758EXPORT_SYMBOL(remap_vmalloc_range);
1759
1760unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1761 unsigned long len, unsigned long pgoff, unsigned long flags)
1762{
1763 return -ENOMEM;
1764}
1765
1766int filemap_fault(struct vm_fault *vmf)
1767{
1768 BUG();
1769 return 0;
1770}
1771EXPORT_SYMBOL(filemap_fault);
1772
1773void filemap_map_pages(struct vm_fault *vmf,
1774 pgoff_t start_pgoff, pgoff_t end_pgoff)
1775{
1776 BUG();
1777}
1778EXPORT_SYMBOL(filemap_map_pages);
1779
1780int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1781 unsigned long addr, void *buf, int len, unsigned int gup_flags)
1782{
1783 struct vm_area_struct *vma;
1784 int write = gup_flags & FOLL_WRITE;
1785
1786 down_read(&mm->mmap_sem);
1787
1788 /* the access must start within one of the target process's mappings */
1789 vma = find_vma(mm, addr);
1790 if (vma) {
1791 /* don't overrun this mapping */
1792 if (addr + len >= vma->vm_end)
1793 len = vma->vm_end - addr;
1794
1795 /* only read or write mappings where it is permitted */
1796 if (write && vma->vm_flags & VM_MAYWRITE)
1797 copy_to_user_page(vma, NULL, addr,
1798 (void *) addr, buf, len);
1799 else if (!write && vma->vm_flags & VM_MAYREAD)
1800 copy_from_user_page(vma, NULL, addr,
1801 buf, (void *) addr, len);
1802 else
1803 len = 0;
1804 } else {
1805 len = 0;
1806 }
1807
1808 up_read(&mm->mmap_sem);
1809
1810 return len;
1811}
1812
1813/**
1814 * access_remote_vm - access another process' address space
1815 * @mm: the mm_struct of the target address space
1816 * @addr: start address to access
1817 * @buf: source or destination buffer
1818 * @len: number of bytes to transfer
1819 * @gup_flags: flags modifying lookup behaviour
1820 *
1821 * The caller must hold a reference on @mm.
1822 */
1823int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1824 void *buf, int len, unsigned int gup_flags)
1825{
1826 return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags);
1827}
1828
1829/*
1830 * Access another process' address space.
1831 * - source/target buffer must be kernel space
1832 */
1833int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
1834 unsigned int gup_flags)
1835{
1836 struct mm_struct *mm;
1837
1838 if (addr + len < addr)
1839 return 0;
1840
1841 mm = get_task_mm(tsk);
1842 if (!mm)
1843 return 0;
1844
1845 len = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
1846
1847 mmput(mm);
1848 return len;
1849}
1850EXPORT_SYMBOL_GPL(access_process_vm);
1851
1852/**
1853 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
1854 * @inode: The inode to check
1855 * @size: The current filesize of the inode
1856 * @newsize: The proposed filesize of the inode
1857 *
1858 * Check the shared mappings on an inode on behalf of a shrinking truncate to
1859 * make sure that that any outstanding VMAs aren't broken and then shrink the
1860 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
1861 * automatically grant mappings that are too large.
1862 */
1863int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
1864 size_t newsize)
1865{
1866 struct vm_area_struct *vma;
1867 struct vm_region *region;
1868 pgoff_t low, high;
1869 size_t r_size, r_top;
1870
1871 low = newsize >> PAGE_SHIFT;
1872 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1873
1874 down_write(&nommu_region_sem);
1875 i_mmap_lock_read(inode->i_mapping);
1876
1877 /* search for VMAs that fall within the dead zone */
1878 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
1879 /* found one - only interested if it's shared out of the page
1880 * cache */
1881 if (vma->vm_flags & VM_SHARED) {
1882 i_mmap_unlock_read(inode->i_mapping);
1883 up_write(&nommu_region_sem);
1884 return -ETXTBSY; /* not quite true, but near enough */
1885 }
1886 }
1887
1888 /* reduce any regions that overlap the dead zone - if in existence,
1889 * these will be pointed to by VMAs that don't overlap the dead zone
1890 *
1891 * we don't check for any regions that start beyond the EOF as there
1892 * shouldn't be any
1893 */
1894 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
1895 if (!(vma->vm_flags & VM_SHARED))
1896 continue;
1897
1898 region = vma->vm_region;
1899 r_size = region->vm_top - region->vm_start;
1900 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
1901
1902 if (r_top > newsize) {
1903 region->vm_top -= r_top - newsize;
1904 if (region->vm_end > region->vm_top)
1905 region->vm_end = region->vm_top;
1906 }
1907 }
1908
1909 i_mmap_unlock_read(inode->i_mapping);
1910 up_write(&nommu_region_sem);
1911 return 0;
1912}
1913
1914/*
1915 * Initialise sysctl_user_reserve_kbytes.
1916 *
1917 * This is intended to prevent a user from starting a single memory hogging
1918 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
1919 * mode.
1920 *
1921 * The default value is min(3% of free memory, 128MB)
1922 * 128MB is enough to recover with sshd/login, bash, and top/kill.
1923 */
1924static int __meminit init_user_reserve(void)
1925{
1926 unsigned long free_kbytes;
1927
1928 free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
1929
1930 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
1931 return 0;
1932}
1933subsys_initcall(init_user_reserve);
1934
1935/*
1936 * Initialise sysctl_admin_reserve_kbytes.
1937 *
1938 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
1939 * to log in and kill a memory hogging process.
1940 *
1941 * Systems with more than 256MB will reserve 8MB, enough to recover
1942 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
1943 * only reserve 3% of free pages by default.
1944 */
1945static int __meminit init_admin_reserve(void)
1946{
1947 unsigned long free_kbytes;
1948
1949 free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
1950
1951 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
1952 return 0;
1953}
1954subsys_initcall(init_admin_reserve);
1/*
2 * linux/mm/nommu.c
3 *
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).
6 *
7 * See Documentation/nommu-mmap.txt
8 *
9 * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
10 * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
11 * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
12 * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
13 * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
14 */
15
16#include <linux/export.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/blkdev.h>
26#include <linux/backing-dev.h>
27#include <linux/mount.h>
28#include <linux/personality.h>
29#include <linux/security.h>
30#include <linux/syscalls.h>
31#include <linux/audit.h>
32
33#include <asm/uaccess.h>
34#include <asm/tlb.h>
35#include <asm/tlbflush.h>
36#include <asm/mmu_context.h>
37#include "internal.h"
38
39#if 0
40#define kenter(FMT, ...) \
41 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
42#define kleave(FMT, ...) \
43 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
44#define kdebug(FMT, ...) \
45 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
46#else
47#define kenter(FMT, ...) \
48 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
49#define kleave(FMT, ...) \
50 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
51#define kdebug(FMT, ...) \
52 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
53#endif
54
55void *high_memory;
56struct page *mem_map;
57unsigned long max_mapnr;
58unsigned long num_physpages;
59unsigned long highest_memmap_pfn;
60struct percpu_counter vm_committed_as;
61int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
62int sysctl_overcommit_ratio = 50; /* default is 50% */
63int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
64int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
65int heap_stack_gap = 0;
66
67atomic_long_t mmap_pages_allocated;
68
69EXPORT_SYMBOL(mem_map);
70EXPORT_SYMBOL(num_physpages);
71
72/* list of mapped, potentially shareable regions */
73static struct kmem_cache *vm_region_jar;
74struct rb_root nommu_region_tree = RB_ROOT;
75DECLARE_RWSEM(nommu_region_sem);
76
77const struct vm_operations_struct generic_file_vm_ops = {
78};
79
80/*
81 * Return the total memory allocated for this pointer, not
82 * just what the caller asked for.
83 *
84 * Doesn't have to be accurate, i.e. may have races.
85 */
86unsigned int kobjsize(const void *objp)
87{
88 struct page *page;
89
90 /*
91 * If the object we have should not have ksize performed on it,
92 * return size of 0
93 */
94 if (!objp || !virt_addr_valid(objp))
95 return 0;
96
97 page = virt_to_head_page(objp);
98
99 /*
100 * If the allocator sets PageSlab, we know the pointer came from
101 * kmalloc().
102 */
103 if (PageSlab(page))
104 return ksize(objp);
105
106 /*
107 * If it's not a compound page, see if we have a matching VMA
108 * region. This test is intentionally done in reverse order,
109 * so if there's no VMA, we still fall through and hand back
110 * PAGE_SIZE for 0-order pages.
111 */
112 if (!PageCompound(page)) {
113 struct vm_area_struct *vma;
114
115 vma = find_vma(current->mm, (unsigned long)objp);
116 if (vma)
117 return vma->vm_end - vma->vm_start;
118 }
119
120 /*
121 * The ksize() function is only guaranteed to work for pointers
122 * returned by kmalloc(). So handle arbitrary pointers here.
123 */
124 return PAGE_SIZE << compound_order(page);
125}
126
127int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
128 unsigned long start, int nr_pages, unsigned int foll_flags,
129 struct page **pages, struct vm_area_struct **vmas,
130 int *retry)
131{
132 struct vm_area_struct *vma;
133 unsigned long vm_flags;
134 int i;
135
136 /* calculate required read or write permissions.
137 * If FOLL_FORCE is set, we only require the "MAY" flags.
138 */
139 vm_flags = (foll_flags & FOLL_WRITE) ?
140 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
141 vm_flags &= (foll_flags & FOLL_FORCE) ?
142 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
143
144 for (i = 0; i < nr_pages; i++) {
145 vma = find_vma(mm, start);
146 if (!vma)
147 goto finish_or_fault;
148
149 /* protect what we can, including chardevs */
150 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
151 !(vm_flags & vma->vm_flags))
152 goto finish_or_fault;
153
154 if (pages) {
155 pages[i] = virt_to_page(start);
156 if (pages[i])
157 page_cache_get(pages[i]);
158 }
159 if (vmas)
160 vmas[i] = vma;
161 start = (start + PAGE_SIZE) & PAGE_MASK;
162 }
163
164 return i;
165
166finish_or_fault:
167 return i ? : -EFAULT;
168}
169
170/*
171 * get a list of pages in an address range belonging to the specified process
172 * and indicate the VMA that covers each page
173 * - this is potentially dodgy as we may end incrementing the page count of a
174 * slab page or a secondary page from a compound page
175 * - don't permit access to VMAs that don't support it, such as I/O mappings
176 */
177int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
178 unsigned long start, int nr_pages, int write, int force,
179 struct page **pages, struct vm_area_struct **vmas)
180{
181 int flags = 0;
182
183 if (write)
184 flags |= FOLL_WRITE;
185 if (force)
186 flags |= FOLL_FORCE;
187
188 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
189 NULL);
190}
191EXPORT_SYMBOL(get_user_pages);
192
193/**
194 * follow_pfn - look up PFN at a user virtual address
195 * @vma: memory mapping
196 * @address: user virtual address
197 * @pfn: location to store found PFN
198 *
199 * Only IO mappings and raw PFN mappings are allowed.
200 *
201 * Returns zero and the pfn at @pfn on success, -ve otherwise.
202 */
203int follow_pfn(struct vm_area_struct *vma, unsigned long address,
204 unsigned long *pfn)
205{
206 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
207 return -EINVAL;
208
209 *pfn = address >> PAGE_SHIFT;
210 return 0;
211}
212EXPORT_SYMBOL(follow_pfn);
213
214DEFINE_RWLOCK(vmlist_lock);
215struct vm_struct *vmlist;
216
217void vfree(const void *addr)
218{
219 kfree(addr);
220}
221EXPORT_SYMBOL(vfree);
222
223void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
224{
225 /*
226 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
227 * returns only a logical address.
228 */
229 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
230}
231EXPORT_SYMBOL(__vmalloc);
232
233void *vmalloc_user(unsigned long size)
234{
235 void *ret;
236
237 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
238 PAGE_KERNEL);
239 if (ret) {
240 struct vm_area_struct *vma;
241
242 down_write(¤t->mm->mmap_sem);
243 vma = find_vma(current->mm, (unsigned long)ret);
244 if (vma)
245 vma->vm_flags |= VM_USERMAP;
246 up_write(¤t->mm->mmap_sem);
247 }
248
249 return ret;
250}
251EXPORT_SYMBOL(vmalloc_user);
252
253struct page *vmalloc_to_page(const void *addr)
254{
255 return virt_to_page(addr);
256}
257EXPORT_SYMBOL(vmalloc_to_page);
258
259unsigned long vmalloc_to_pfn(const void *addr)
260{
261 return page_to_pfn(virt_to_page(addr));
262}
263EXPORT_SYMBOL(vmalloc_to_pfn);
264
265long vread(char *buf, char *addr, unsigned long count)
266{
267 memcpy(buf, addr, count);
268 return count;
269}
270
271long vwrite(char *buf, char *addr, unsigned long count)
272{
273 /* Don't allow overflow */
274 if ((unsigned long) addr + count < count)
275 count = -(unsigned long) addr;
276
277 memcpy(addr, buf, count);
278 return(count);
279}
280
281/*
282 * vmalloc - allocate virtually continguos memory
283 *
284 * @size: allocation size
285 *
286 * Allocate enough pages to cover @size from the page level
287 * allocator and map them into continguos kernel virtual space.
288 *
289 * For tight control over page level allocator and protection flags
290 * use __vmalloc() instead.
291 */
292void *vmalloc(unsigned long size)
293{
294 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
295}
296EXPORT_SYMBOL(vmalloc);
297
298/*
299 * vzalloc - allocate virtually continguos memory with zero fill
300 *
301 * @size: allocation size
302 *
303 * Allocate enough pages to cover @size from the page level
304 * allocator and map them into continguos kernel virtual space.
305 * The memory allocated is set to zero.
306 *
307 * For tight control over page level allocator and protection flags
308 * use __vmalloc() instead.
309 */
310void *vzalloc(unsigned long size)
311{
312 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
313 PAGE_KERNEL);
314}
315EXPORT_SYMBOL(vzalloc);
316
317/**
318 * vmalloc_node - allocate memory on a specific node
319 * @size: allocation size
320 * @node: numa node
321 *
322 * Allocate enough pages to cover @size from the page level
323 * allocator and map them into contiguous kernel virtual space.
324 *
325 * For tight control over page level allocator and protection flags
326 * use __vmalloc() instead.
327 */
328void *vmalloc_node(unsigned long size, int node)
329{
330 return vmalloc(size);
331}
332EXPORT_SYMBOL(vmalloc_node);
333
334/**
335 * vzalloc_node - allocate memory on a specific node with zero fill
336 * @size: allocation size
337 * @node: numa node
338 *
339 * Allocate enough pages to cover @size from the page level
340 * allocator and map them into contiguous kernel virtual space.
341 * The memory allocated is set to zero.
342 *
343 * For tight control over page level allocator and protection flags
344 * use __vmalloc() instead.
345 */
346void *vzalloc_node(unsigned long size, int node)
347{
348 return vzalloc(size);
349}
350EXPORT_SYMBOL(vzalloc_node);
351
352#ifndef PAGE_KERNEL_EXEC
353# define PAGE_KERNEL_EXEC PAGE_KERNEL
354#endif
355
356/**
357 * vmalloc_exec - allocate virtually contiguous, executable memory
358 * @size: allocation size
359 *
360 * Kernel-internal function to allocate enough pages to cover @size
361 * the page level allocator and map them into contiguous and
362 * executable kernel virtual space.
363 *
364 * For tight control over page level allocator and protection flags
365 * use __vmalloc() instead.
366 */
367
368void *vmalloc_exec(unsigned long size)
369{
370 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
371}
372
373/**
374 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
375 * @size: allocation size
376 *
377 * Allocate enough 32bit PA addressable pages to cover @size from the
378 * page level allocator and map them into continguos kernel virtual space.
379 */
380void *vmalloc_32(unsigned long size)
381{
382 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
383}
384EXPORT_SYMBOL(vmalloc_32);
385
386/**
387 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
388 * @size: allocation size
389 *
390 * The resulting memory area is 32bit addressable and zeroed so it can be
391 * mapped to userspace without leaking data.
392 *
393 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
394 * remap_vmalloc_range() are permissible.
395 */
396void *vmalloc_32_user(unsigned long size)
397{
398 /*
399 * We'll have to sort out the ZONE_DMA bits for 64-bit,
400 * but for now this can simply use vmalloc_user() directly.
401 */
402 return vmalloc_user(size);
403}
404EXPORT_SYMBOL(vmalloc_32_user);
405
406void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
407{
408 BUG();
409 return NULL;
410}
411EXPORT_SYMBOL(vmap);
412
413void vunmap(const void *addr)
414{
415 BUG();
416}
417EXPORT_SYMBOL(vunmap);
418
419void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
420{
421 BUG();
422 return NULL;
423}
424EXPORT_SYMBOL(vm_map_ram);
425
426void vm_unmap_ram(const void *mem, unsigned int count)
427{
428 BUG();
429}
430EXPORT_SYMBOL(vm_unmap_ram);
431
432void vm_unmap_aliases(void)
433{
434}
435EXPORT_SYMBOL_GPL(vm_unmap_aliases);
436
437/*
438 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
439 * have one.
440 */
441void __attribute__((weak)) vmalloc_sync_all(void)
442{
443}
444
445/**
446 * alloc_vm_area - allocate a range of kernel address space
447 * @size: size of the area
448 *
449 * Returns: NULL on failure, vm_struct on success
450 *
451 * This function reserves a range of kernel address space, and
452 * allocates pagetables to map that range. No actual mappings
453 * are created. If the kernel address space is not shared
454 * between processes, it syncs the pagetable across all
455 * processes.
456 */
457struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
458{
459 BUG();
460 return NULL;
461}
462EXPORT_SYMBOL_GPL(alloc_vm_area);
463
464void free_vm_area(struct vm_struct *area)
465{
466 BUG();
467}
468EXPORT_SYMBOL_GPL(free_vm_area);
469
470int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
471 struct page *page)
472{
473 return -EINVAL;
474}
475EXPORT_SYMBOL(vm_insert_page);
476
477/*
478 * sys_brk() for the most part doesn't need the global kernel
479 * lock, except when an application is doing something nasty
480 * like trying to un-brk an area that has already been mapped
481 * to a regular file. in this case, the unmapping will need
482 * to invoke file system routines that need the global lock.
483 */
484SYSCALL_DEFINE1(brk, unsigned long, brk)
485{
486 struct mm_struct *mm = current->mm;
487
488 if (brk < mm->start_brk || brk > mm->context.end_brk)
489 return mm->brk;
490
491 if (mm->brk == brk)
492 return mm->brk;
493
494 /*
495 * Always allow shrinking brk
496 */
497 if (brk <= mm->brk) {
498 mm->brk = brk;
499 return brk;
500 }
501
502 /*
503 * Ok, looks good - let it rip.
504 */
505 flush_icache_range(mm->brk, brk);
506 return mm->brk = brk;
507}
508
509/*
510 * initialise the VMA and region record slabs
511 */
512void __init mmap_init(void)
513{
514 int ret;
515
516 ret = percpu_counter_init(&vm_committed_as, 0);
517 VM_BUG_ON(ret);
518 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
519}
520
521/*
522 * validate the region tree
523 * - the caller must hold the region lock
524 */
525#ifdef CONFIG_DEBUG_NOMMU_REGIONS
526static noinline void validate_nommu_regions(void)
527{
528 struct vm_region *region, *last;
529 struct rb_node *p, *lastp;
530
531 lastp = rb_first(&nommu_region_tree);
532 if (!lastp)
533 return;
534
535 last = rb_entry(lastp, struct vm_region, vm_rb);
536 BUG_ON(unlikely(last->vm_end <= last->vm_start));
537 BUG_ON(unlikely(last->vm_top < last->vm_end));
538
539 while ((p = rb_next(lastp))) {
540 region = rb_entry(p, struct vm_region, vm_rb);
541 last = rb_entry(lastp, struct vm_region, vm_rb);
542
543 BUG_ON(unlikely(region->vm_end <= region->vm_start));
544 BUG_ON(unlikely(region->vm_top < region->vm_end));
545 BUG_ON(unlikely(region->vm_start < last->vm_top));
546
547 lastp = p;
548 }
549}
550#else
551static void validate_nommu_regions(void)
552{
553}
554#endif
555
556/*
557 * add a region into the global tree
558 */
559static void add_nommu_region(struct vm_region *region)
560{
561 struct vm_region *pregion;
562 struct rb_node **p, *parent;
563
564 validate_nommu_regions();
565
566 parent = NULL;
567 p = &nommu_region_tree.rb_node;
568 while (*p) {
569 parent = *p;
570 pregion = rb_entry(parent, struct vm_region, vm_rb);
571 if (region->vm_start < pregion->vm_start)
572 p = &(*p)->rb_left;
573 else if (region->vm_start > pregion->vm_start)
574 p = &(*p)->rb_right;
575 else if (pregion == region)
576 return;
577 else
578 BUG();
579 }
580
581 rb_link_node(®ion->vm_rb, parent, p);
582 rb_insert_color(®ion->vm_rb, &nommu_region_tree);
583
584 validate_nommu_regions();
585}
586
587/*
588 * delete a region from the global tree
589 */
590static void delete_nommu_region(struct vm_region *region)
591{
592 BUG_ON(!nommu_region_tree.rb_node);
593
594 validate_nommu_regions();
595 rb_erase(®ion->vm_rb, &nommu_region_tree);
596 validate_nommu_regions();
597}
598
599/*
600 * free a contiguous series of pages
601 */
602static void free_page_series(unsigned long from, unsigned long to)
603{
604 for (; from < to; from += PAGE_SIZE) {
605 struct page *page = virt_to_page(from);
606
607 kdebug("- free %lx", from);
608 atomic_long_dec(&mmap_pages_allocated);
609 if (page_count(page) != 1)
610 kdebug("free page %p: refcount not one: %d",
611 page, page_count(page));
612 put_page(page);
613 }
614}
615
616/*
617 * release a reference to a region
618 * - the caller must hold the region semaphore for writing, which this releases
619 * - the region may not have been added to the tree yet, in which case vm_top
620 * will equal vm_start
621 */
622static void __put_nommu_region(struct vm_region *region)
623 __releases(nommu_region_sem)
624{
625 kenter("%p{%d}", region, region->vm_usage);
626
627 BUG_ON(!nommu_region_tree.rb_node);
628
629 if (--region->vm_usage == 0) {
630 if (region->vm_top > region->vm_start)
631 delete_nommu_region(region);
632 up_write(&nommu_region_sem);
633
634 if (region->vm_file)
635 fput(region->vm_file);
636
637 /* IO memory and memory shared directly out of the pagecache
638 * from ramfs/tmpfs mustn't be released here */
639 if (region->vm_flags & VM_MAPPED_COPY) {
640 kdebug("free series");
641 free_page_series(region->vm_start, region->vm_top);
642 }
643 kmem_cache_free(vm_region_jar, region);
644 } else {
645 up_write(&nommu_region_sem);
646 }
647}
648
649/*
650 * release a reference to a region
651 */
652static void put_nommu_region(struct vm_region *region)
653{
654 down_write(&nommu_region_sem);
655 __put_nommu_region(region);
656}
657
658/*
659 * update protection on a vma
660 */
661static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
662{
663#ifdef CONFIG_MPU
664 struct mm_struct *mm = vma->vm_mm;
665 long start = vma->vm_start & PAGE_MASK;
666 while (start < vma->vm_end) {
667 protect_page(mm, start, flags);
668 start += PAGE_SIZE;
669 }
670 update_protections(mm);
671#endif
672}
673
674/*
675 * add a VMA into a process's mm_struct in the appropriate place in the list
676 * and tree and add to the address space's page tree also if not an anonymous
677 * page
678 * - should be called with mm->mmap_sem held writelocked
679 */
680static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
681{
682 struct vm_area_struct *pvma, *prev;
683 struct address_space *mapping;
684 struct rb_node **p, *parent, *rb_prev;
685
686 kenter(",%p", vma);
687
688 BUG_ON(!vma->vm_region);
689
690 mm->map_count++;
691 vma->vm_mm = mm;
692
693 protect_vma(vma, vma->vm_flags);
694
695 /* add the VMA to the mapping */
696 if (vma->vm_file) {
697 mapping = vma->vm_file->f_mapping;
698
699 mutex_lock(&mapping->i_mmap_mutex);
700 flush_dcache_mmap_lock(mapping);
701 vma_prio_tree_insert(vma, &mapping->i_mmap);
702 flush_dcache_mmap_unlock(mapping);
703 mutex_unlock(&mapping->i_mmap_mutex);
704 }
705
706 /* add the VMA to the tree */
707 parent = rb_prev = NULL;
708 p = &mm->mm_rb.rb_node;
709 while (*p) {
710 parent = *p;
711 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
712
713 /* sort by: start addr, end addr, VMA struct addr in that order
714 * (the latter is necessary as we may get identical VMAs) */
715 if (vma->vm_start < pvma->vm_start)
716 p = &(*p)->rb_left;
717 else if (vma->vm_start > pvma->vm_start) {
718 rb_prev = parent;
719 p = &(*p)->rb_right;
720 } else if (vma->vm_end < pvma->vm_end)
721 p = &(*p)->rb_left;
722 else if (vma->vm_end > pvma->vm_end) {
723 rb_prev = parent;
724 p = &(*p)->rb_right;
725 } else if (vma < pvma)
726 p = &(*p)->rb_left;
727 else if (vma > pvma) {
728 rb_prev = parent;
729 p = &(*p)->rb_right;
730 } else
731 BUG();
732 }
733
734 rb_link_node(&vma->vm_rb, parent, p);
735 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
736
737 /* add VMA to the VMA list also */
738 prev = NULL;
739 if (rb_prev)
740 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
741
742 __vma_link_list(mm, vma, prev, parent);
743}
744
745/*
746 * delete a VMA from its owning mm_struct and address space
747 */
748static void delete_vma_from_mm(struct vm_area_struct *vma)
749{
750 struct address_space *mapping;
751 struct mm_struct *mm = vma->vm_mm;
752
753 kenter("%p", vma);
754
755 protect_vma(vma, 0);
756
757 mm->map_count--;
758 if (mm->mmap_cache == vma)
759 mm->mmap_cache = NULL;
760
761 /* remove the VMA from the mapping */
762 if (vma->vm_file) {
763 mapping = vma->vm_file->f_mapping;
764
765 mutex_lock(&mapping->i_mmap_mutex);
766 flush_dcache_mmap_lock(mapping);
767 vma_prio_tree_remove(vma, &mapping->i_mmap);
768 flush_dcache_mmap_unlock(mapping);
769 mutex_unlock(&mapping->i_mmap_mutex);
770 }
771
772 /* remove from the MM's tree and list */
773 rb_erase(&vma->vm_rb, &mm->mm_rb);
774
775 if (vma->vm_prev)
776 vma->vm_prev->vm_next = vma->vm_next;
777 else
778 mm->mmap = vma->vm_next;
779
780 if (vma->vm_next)
781 vma->vm_next->vm_prev = vma->vm_prev;
782}
783
784/*
785 * destroy a VMA record
786 */
787static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
788{
789 kenter("%p", vma);
790 if (vma->vm_ops && vma->vm_ops->close)
791 vma->vm_ops->close(vma);
792 if (vma->vm_file) {
793 fput(vma->vm_file);
794 if (vma->vm_flags & VM_EXECUTABLE)
795 removed_exe_file_vma(mm);
796 }
797 put_nommu_region(vma->vm_region);
798 kmem_cache_free(vm_area_cachep, vma);
799}
800
801/*
802 * look up the first VMA in which addr resides, NULL if none
803 * - should be called with mm->mmap_sem at least held readlocked
804 */
805struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
806{
807 struct vm_area_struct *vma;
808
809 /* check the cache first */
810 vma = mm->mmap_cache;
811 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
812 return vma;
813
814 /* trawl the list (there may be multiple mappings in which addr
815 * resides) */
816 for (vma = mm->mmap; vma; vma = vma->vm_next) {
817 if (vma->vm_start > addr)
818 return NULL;
819 if (vma->vm_end > addr) {
820 mm->mmap_cache = vma;
821 return vma;
822 }
823 }
824
825 return NULL;
826}
827EXPORT_SYMBOL(find_vma);
828
829/*
830 * find a VMA
831 * - we don't extend stack VMAs under NOMMU conditions
832 */
833struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
834{
835 return find_vma(mm, addr);
836}
837
838/*
839 * expand a stack to a given address
840 * - not supported under NOMMU conditions
841 */
842int expand_stack(struct vm_area_struct *vma, unsigned long address)
843{
844 return -ENOMEM;
845}
846
847/*
848 * look up the first VMA exactly that exactly matches addr
849 * - should be called with mm->mmap_sem at least held readlocked
850 */
851static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
852 unsigned long addr,
853 unsigned long len)
854{
855 struct vm_area_struct *vma;
856 unsigned long end = addr + len;
857
858 /* check the cache first */
859 vma = mm->mmap_cache;
860 if (vma && vma->vm_start == addr && vma->vm_end == end)
861 return vma;
862
863 /* trawl the list (there may be multiple mappings in which addr
864 * resides) */
865 for (vma = mm->mmap; vma; vma = vma->vm_next) {
866 if (vma->vm_start < addr)
867 continue;
868 if (vma->vm_start > addr)
869 return NULL;
870 if (vma->vm_end == end) {
871 mm->mmap_cache = vma;
872 return vma;
873 }
874 }
875
876 return NULL;
877}
878
879/*
880 * determine whether a mapping should be permitted and, if so, what sort of
881 * mapping we're capable of supporting
882 */
883static int validate_mmap_request(struct file *file,
884 unsigned long addr,
885 unsigned long len,
886 unsigned long prot,
887 unsigned long flags,
888 unsigned long pgoff,
889 unsigned long *_capabilities)
890{
891 unsigned long capabilities, rlen;
892 int ret;
893
894 /* do the simple checks first */
895 if (flags & MAP_FIXED) {
896 printk(KERN_DEBUG
897 "%d: Can't do fixed-address/overlay mmap of RAM\n",
898 current->pid);
899 return -EINVAL;
900 }
901
902 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
903 (flags & MAP_TYPE) != MAP_SHARED)
904 return -EINVAL;
905
906 if (!len)
907 return -EINVAL;
908
909 /* Careful about overflows.. */
910 rlen = PAGE_ALIGN(len);
911 if (!rlen || rlen > TASK_SIZE)
912 return -ENOMEM;
913
914 /* offset overflow? */
915 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
916 return -EOVERFLOW;
917
918 if (file) {
919 /* validate file mapping requests */
920 struct address_space *mapping;
921
922 /* files must support mmap */
923 if (!file->f_op || !file->f_op->mmap)
924 return -ENODEV;
925
926 /* work out if what we've got could possibly be shared
927 * - we support chardevs that provide their own "memory"
928 * - we support files/blockdevs that are memory backed
929 */
930 mapping = file->f_mapping;
931 if (!mapping)
932 mapping = file->f_path.dentry->d_inode->i_mapping;
933
934 capabilities = 0;
935 if (mapping && mapping->backing_dev_info)
936 capabilities = mapping->backing_dev_info->capabilities;
937
938 if (!capabilities) {
939 /* no explicit capabilities set, so assume some
940 * defaults */
941 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
942 case S_IFREG:
943 case S_IFBLK:
944 capabilities = BDI_CAP_MAP_COPY;
945 break;
946
947 case S_IFCHR:
948 capabilities =
949 BDI_CAP_MAP_DIRECT |
950 BDI_CAP_READ_MAP |
951 BDI_CAP_WRITE_MAP;
952 break;
953
954 default:
955 return -EINVAL;
956 }
957 }
958
959 /* eliminate any capabilities that we can't support on this
960 * device */
961 if (!file->f_op->get_unmapped_area)
962 capabilities &= ~BDI_CAP_MAP_DIRECT;
963 if (!file->f_op->read)
964 capabilities &= ~BDI_CAP_MAP_COPY;
965
966 /* The file shall have been opened with read permission. */
967 if (!(file->f_mode & FMODE_READ))
968 return -EACCES;
969
970 if (flags & MAP_SHARED) {
971 /* do checks for writing, appending and locking */
972 if ((prot & PROT_WRITE) &&
973 !(file->f_mode & FMODE_WRITE))
974 return -EACCES;
975
976 if (IS_APPEND(file->f_path.dentry->d_inode) &&
977 (file->f_mode & FMODE_WRITE))
978 return -EACCES;
979
980 if (locks_verify_locked(file->f_path.dentry->d_inode))
981 return -EAGAIN;
982
983 if (!(capabilities & BDI_CAP_MAP_DIRECT))
984 return -ENODEV;
985
986 /* we mustn't privatise shared mappings */
987 capabilities &= ~BDI_CAP_MAP_COPY;
988 }
989 else {
990 /* we're going to read the file into private memory we
991 * allocate */
992 if (!(capabilities & BDI_CAP_MAP_COPY))
993 return -ENODEV;
994
995 /* we don't permit a private writable mapping to be
996 * shared with the backing device */
997 if (prot & PROT_WRITE)
998 capabilities &= ~BDI_CAP_MAP_DIRECT;
999 }
1000
1001 if (capabilities & BDI_CAP_MAP_DIRECT) {
1002 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
1003 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
1004 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
1005 ) {
1006 capabilities &= ~BDI_CAP_MAP_DIRECT;
1007 if (flags & MAP_SHARED) {
1008 printk(KERN_WARNING
1009 "MAP_SHARED not completely supported on !MMU\n");
1010 return -EINVAL;
1011 }
1012 }
1013 }
1014
1015 /* handle executable mappings and implied executable
1016 * mappings */
1017 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
1018 if (prot & PROT_EXEC)
1019 return -EPERM;
1020 }
1021 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
1022 /* handle implication of PROT_EXEC by PROT_READ */
1023 if (current->personality & READ_IMPLIES_EXEC) {
1024 if (capabilities & BDI_CAP_EXEC_MAP)
1025 prot |= PROT_EXEC;
1026 }
1027 }
1028 else if ((prot & PROT_READ) &&
1029 (prot & PROT_EXEC) &&
1030 !(capabilities & BDI_CAP_EXEC_MAP)
1031 ) {
1032 /* backing file is not executable, try to copy */
1033 capabilities &= ~BDI_CAP_MAP_DIRECT;
1034 }
1035 }
1036 else {
1037 /* anonymous mappings are always memory backed and can be
1038 * privately mapped
1039 */
1040 capabilities = BDI_CAP_MAP_COPY;
1041
1042 /* handle PROT_EXEC implication by PROT_READ */
1043 if ((prot & PROT_READ) &&
1044 (current->personality & READ_IMPLIES_EXEC))
1045 prot |= PROT_EXEC;
1046 }
1047
1048 /* allow the security API to have its say */
1049 ret = security_mmap_addr(addr);
1050 if (ret < 0)
1051 return ret;
1052
1053 /* looks okay */
1054 *_capabilities = capabilities;
1055 return 0;
1056}
1057
1058/*
1059 * we've determined that we can make the mapping, now translate what we
1060 * now know into VMA flags
1061 */
1062static unsigned long determine_vm_flags(struct file *file,
1063 unsigned long prot,
1064 unsigned long flags,
1065 unsigned long capabilities)
1066{
1067 unsigned long vm_flags;
1068
1069 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
1070 /* vm_flags |= mm->def_flags; */
1071
1072 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1073 /* attempt to share read-only copies of mapped file chunks */
1074 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1075 if (file && !(prot & PROT_WRITE))
1076 vm_flags |= VM_MAYSHARE;
1077 } else {
1078 /* overlay a shareable mapping on the backing device or inode
1079 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1080 * romfs/cramfs */
1081 vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS);
1082 if (flags & MAP_SHARED)
1083 vm_flags |= VM_SHARED;
1084 }
1085
1086 /* refuse to let anyone share private mappings with this process if
1087 * it's being traced - otherwise breakpoints set in it may interfere
1088 * with another untraced process
1089 */
1090 if ((flags & MAP_PRIVATE) && current->ptrace)
1091 vm_flags &= ~VM_MAYSHARE;
1092
1093 return vm_flags;
1094}
1095
1096/*
1097 * set up a shared mapping on a file (the driver or filesystem provides and
1098 * pins the storage)
1099 */
1100static int do_mmap_shared_file(struct vm_area_struct *vma)
1101{
1102 int ret;
1103
1104 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1105 if (ret == 0) {
1106 vma->vm_region->vm_top = vma->vm_region->vm_end;
1107 return 0;
1108 }
1109 if (ret != -ENOSYS)
1110 return ret;
1111
1112 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1113 * opposed to tried but failed) so we can only give a suitable error as
1114 * it's not possible to make a private copy if MAP_SHARED was given */
1115 return -ENODEV;
1116}
1117
1118/*
1119 * set up a private mapping or an anonymous shared mapping
1120 */
1121static int do_mmap_private(struct vm_area_struct *vma,
1122 struct vm_region *region,
1123 unsigned long len,
1124 unsigned long capabilities)
1125{
1126 struct page *pages;
1127 unsigned long total, point, n;
1128 void *base;
1129 int ret, order;
1130
1131 /* invoke the file's mapping function so that it can keep track of
1132 * shared mappings on devices or memory
1133 * - VM_MAYSHARE will be set if it may attempt to share
1134 */
1135 if (capabilities & BDI_CAP_MAP_DIRECT) {
1136 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1137 if (ret == 0) {
1138 /* shouldn't return success if we're not sharing */
1139 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1140 vma->vm_region->vm_top = vma->vm_region->vm_end;
1141 return 0;
1142 }
1143 if (ret != -ENOSYS)
1144 return ret;
1145
1146 /* getting an ENOSYS error indicates that direct mmap isn't
1147 * possible (as opposed to tried but failed) so we'll try to
1148 * make a private copy of the data and map that instead */
1149 }
1150
1151
1152 /* allocate some memory to hold the mapping
1153 * - note that this may not return a page-aligned address if the object
1154 * we're allocating is smaller than a page
1155 */
1156 order = get_order(len);
1157 kdebug("alloc order %d for %lx", order, len);
1158
1159 pages = alloc_pages(GFP_KERNEL, order);
1160 if (!pages)
1161 goto enomem;
1162
1163 total = 1 << order;
1164 atomic_long_add(total, &mmap_pages_allocated);
1165
1166 point = len >> PAGE_SHIFT;
1167
1168 /* we allocated a power-of-2 sized page set, so we may want to trim off
1169 * the excess */
1170 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1171 while (total > point) {
1172 order = ilog2(total - point);
1173 n = 1 << order;
1174 kdebug("shave %lu/%lu @%lu", n, total - point, total);
1175 atomic_long_sub(n, &mmap_pages_allocated);
1176 total -= n;
1177 set_page_refcounted(pages + total);
1178 __free_pages(pages + total, order);
1179 }
1180 }
1181
1182 for (point = 1; point < total; point++)
1183 set_page_refcounted(&pages[point]);
1184
1185 base = page_address(pages);
1186 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1187 region->vm_start = (unsigned long) base;
1188 region->vm_end = region->vm_start + len;
1189 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1190
1191 vma->vm_start = region->vm_start;
1192 vma->vm_end = region->vm_start + len;
1193
1194 if (vma->vm_file) {
1195 /* read the contents of a file into the copy */
1196 mm_segment_t old_fs;
1197 loff_t fpos;
1198
1199 fpos = vma->vm_pgoff;
1200 fpos <<= PAGE_SHIFT;
1201
1202 old_fs = get_fs();
1203 set_fs(KERNEL_DS);
1204 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
1205 set_fs(old_fs);
1206
1207 if (ret < 0)
1208 goto error_free;
1209
1210 /* clear the last little bit */
1211 if (ret < len)
1212 memset(base + ret, 0, len - ret);
1213
1214 }
1215
1216 return 0;
1217
1218error_free:
1219 free_page_series(region->vm_start, region->vm_top);
1220 region->vm_start = vma->vm_start = 0;
1221 region->vm_end = vma->vm_end = 0;
1222 region->vm_top = 0;
1223 return ret;
1224
1225enomem:
1226 printk("Allocation of length %lu from process %d (%s) failed\n",
1227 len, current->pid, current->comm);
1228 show_free_areas(0);
1229 return -ENOMEM;
1230}
1231
1232/*
1233 * handle mapping creation for uClinux
1234 */
1235unsigned long do_mmap_pgoff(struct file *file,
1236 unsigned long addr,
1237 unsigned long len,
1238 unsigned long prot,
1239 unsigned long flags,
1240 unsigned long pgoff)
1241{
1242 struct vm_area_struct *vma;
1243 struct vm_region *region;
1244 struct rb_node *rb;
1245 unsigned long capabilities, vm_flags, result;
1246 int ret;
1247
1248 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1249
1250 /* decide whether we should attempt the mapping, and if so what sort of
1251 * mapping */
1252 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1253 &capabilities);
1254 if (ret < 0) {
1255 kleave(" = %d [val]", ret);
1256 return ret;
1257 }
1258
1259 /* we ignore the address hint */
1260 addr = 0;
1261 len = PAGE_ALIGN(len);
1262
1263 /* we've determined that we can make the mapping, now translate what we
1264 * now know into VMA flags */
1265 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1266
1267 /* we're going to need to record the mapping */
1268 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1269 if (!region)
1270 goto error_getting_region;
1271
1272 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1273 if (!vma)
1274 goto error_getting_vma;
1275
1276 region->vm_usage = 1;
1277 region->vm_flags = vm_flags;
1278 region->vm_pgoff = pgoff;
1279
1280 INIT_LIST_HEAD(&vma->anon_vma_chain);
1281 vma->vm_flags = vm_flags;
1282 vma->vm_pgoff = pgoff;
1283
1284 if (file) {
1285 region->vm_file = file;
1286 get_file(file);
1287 vma->vm_file = file;
1288 get_file(file);
1289 if (vm_flags & VM_EXECUTABLE) {
1290 added_exe_file_vma(current->mm);
1291 vma->vm_mm = current->mm;
1292 }
1293 }
1294
1295 down_write(&nommu_region_sem);
1296
1297 /* if we want to share, we need to check for regions created by other
1298 * mmap() calls that overlap with our proposed mapping
1299 * - we can only share with a superset match on most regular files
1300 * - shared mappings on character devices and memory backed files are
1301 * permitted to overlap inexactly as far as we are concerned for in
1302 * these cases, sharing is handled in the driver or filesystem rather
1303 * than here
1304 */
1305 if (vm_flags & VM_MAYSHARE) {
1306 struct vm_region *pregion;
1307 unsigned long pglen, rpglen, pgend, rpgend, start;
1308
1309 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1310 pgend = pgoff + pglen;
1311
1312 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1313 pregion = rb_entry(rb, struct vm_region, vm_rb);
1314
1315 if (!(pregion->vm_flags & VM_MAYSHARE))
1316 continue;
1317
1318 /* search for overlapping mappings on the same file */
1319 if (pregion->vm_file->f_path.dentry->d_inode !=
1320 file->f_path.dentry->d_inode)
1321 continue;
1322
1323 if (pregion->vm_pgoff >= pgend)
1324 continue;
1325
1326 rpglen = pregion->vm_end - pregion->vm_start;
1327 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1328 rpgend = pregion->vm_pgoff + rpglen;
1329 if (pgoff >= rpgend)
1330 continue;
1331
1332 /* handle inexactly overlapping matches between
1333 * mappings */
1334 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1335 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1336 /* new mapping is not a subset of the region */
1337 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1338 goto sharing_violation;
1339 continue;
1340 }
1341
1342 /* we've found a region we can share */
1343 pregion->vm_usage++;
1344 vma->vm_region = pregion;
1345 start = pregion->vm_start;
1346 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1347 vma->vm_start = start;
1348 vma->vm_end = start + len;
1349
1350 if (pregion->vm_flags & VM_MAPPED_COPY) {
1351 kdebug("share copy");
1352 vma->vm_flags |= VM_MAPPED_COPY;
1353 } else {
1354 kdebug("share mmap");
1355 ret = do_mmap_shared_file(vma);
1356 if (ret < 0) {
1357 vma->vm_region = NULL;
1358 vma->vm_start = 0;
1359 vma->vm_end = 0;
1360 pregion->vm_usage--;
1361 pregion = NULL;
1362 goto error_just_free;
1363 }
1364 }
1365 fput(region->vm_file);
1366 kmem_cache_free(vm_region_jar, region);
1367 region = pregion;
1368 result = start;
1369 goto share;
1370 }
1371
1372 /* obtain the address at which to make a shared mapping
1373 * - this is the hook for quasi-memory character devices to
1374 * tell us the location of a shared mapping
1375 */
1376 if (capabilities & BDI_CAP_MAP_DIRECT) {
1377 addr = file->f_op->get_unmapped_area(file, addr, len,
1378 pgoff, flags);
1379 if (IS_ERR_VALUE(addr)) {
1380 ret = addr;
1381 if (ret != -ENOSYS)
1382 goto error_just_free;
1383
1384 /* the driver refused to tell us where to site
1385 * the mapping so we'll have to attempt to copy
1386 * it */
1387 ret = -ENODEV;
1388 if (!(capabilities & BDI_CAP_MAP_COPY))
1389 goto error_just_free;
1390
1391 capabilities &= ~BDI_CAP_MAP_DIRECT;
1392 } else {
1393 vma->vm_start = region->vm_start = addr;
1394 vma->vm_end = region->vm_end = addr + len;
1395 }
1396 }
1397 }
1398
1399 vma->vm_region = region;
1400
1401 /* set up the mapping
1402 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1403 */
1404 if (file && vma->vm_flags & VM_SHARED)
1405 ret = do_mmap_shared_file(vma);
1406 else
1407 ret = do_mmap_private(vma, region, len, capabilities);
1408 if (ret < 0)
1409 goto error_just_free;
1410 add_nommu_region(region);
1411
1412 /* clear anonymous mappings that don't ask for uninitialized data */
1413 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1414 memset((void *)region->vm_start, 0,
1415 region->vm_end - region->vm_start);
1416
1417 /* okay... we have a mapping; now we have to register it */
1418 result = vma->vm_start;
1419
1420 current->mm->total_vm += len >> PAGE_SHIFT;
1421
1422share:
1423 add_vma_to_mm(current->mm, vma);
1424
1425 /* we flush the region from the icache only when the first executable
1426 * mapping of it is made */
1427 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1428 flush_icache_range(region->vm_start, region->vm_end);
1429 region->vm_icache_flushed = true;
1430 }
1431
1432 up_write(&nommu_region_sem);
1433
1434 kleave(" = %lx", result);
1435 return result;
1436
1437error_just_free:
1438 up_write(&nommu_region_sem);
1439error:
1440 if (region->vm_file)
1441 fput(region->vm_file);
1442 kmem_cache_free(vm_region_jar, region);
1443 if (vma->vm_file)
1444 fput(vma->vm_file);
1445 if (vma->vm_flags & VM_EXECUTABLE)
1446 removed_exe_file_vma(vma->vm_mm);
1447 kmem_cache_free(vm_area_cachep, vma);
1448 kleave(" = %d", ret);
1449 return ret;
1450
1451sharing_violation:
1452 up_write(&nommu_region_sem);
1453 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1454 ret = -EINVAL;
1455 goto error;
1456
1457error_getting_vma:
1458 kmem_cache_free(vm_region_jar, region);
1459 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1460 " from process %d failed\n",
1461 len, current->pid);
1462 show_free_areas(0);
1463 return -ENOMEM;
1464
1465error_getting_region:
1466 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1467 " from process %d failed\n",
1468 len, current->pid);
1469 show_free_areas(0);
1470 return -ENOMEM;
1471}
1472
1473SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1474 unsigned long, prot, unsigned long, flags,
1475 unsigned long, fd, unsigned long, pgoff)
1476{
1477 struct file *file = NULL;
1478 unsigned long retval = -EBADF;
1479
1480 audit_mmap_fd(fd, flags);
1481 if (!(flags & MAP_ANONYMOUS)) {
1482 file = fget(fd);
1483 if (!file)
1484 goto out;
1485 }
1486
1487 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1488
1489 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1490
1491 if (file)
1492 fput(file);
1493out:
1494 return retval;
1495}
1496
1497#ifdef __ARCH_WANT_SYS_OLD_MMAP
1498struct mmap_arg_struct {
1499 unsigned long addr;
1500 unsigned long len;
1501 unsigned long prot;
1502 unsigned long flags;
1503 unsigned long fd;
1504 unsigned long offset;
1505};
1506
1507SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1508{
1509 struct mmap_arg_struct a;
1510
1511 if (copy_from_user(&a, arg, sizeof(a)))
1512 return -EFAULT;
1513 if (a.offset & ~PAGE_MASK)
1514 return -EINVAL;
1515
1516 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1517 a.offset >> PAGE_SHIFT);
1518}
1519#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1520
1521/*
1522 * split a vma into two pieces at address 'addr', a new vma is allocated either
1523 * for the first part or the tail.
1524 */
1525int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1526 unsigned long addr, int new_below)
1527{
1528 struct vm_area_struct *new;
1529 struct vm_region *region;
1530 unsigned long npages;
1531
1532 kenter("");
1533
1534 /* we're only permitted to split anonymous regions (these should have
1535 * only a single usage on the region) */
1536 if (vma->vm_file)
1537 return -ENOMEM;
1538
1539 if (mm->map_count >= sysctl_max_map_count)
1540 return -ENOMEM;
1541
1542 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1543 if (!region)
1544 return -ENOMEM;
1545
1546 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1547 if (!new) {
1548 kmem_cache_free(vm_region_jar, region);
1549 return -ENOMEM;
1550 }
1551
1552 /* most fields are the same, copy all, and then fixup */
1553 *new = *vma;
1554 *region = *vma->vm_region;
1555 new->vm_region = region;
1556
1557 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1558
1559 if (new_below) {
1560 region->vm_top = region->vm_end = new->vm_end = addr;
1561 } else {
1562 region->vm_start = new->vm_start = addr;
1563 region->vm_pgoff = new->vm_pgoff += npages;
1564 }
1565
1566 if (new->vm_ops && new->vm_ops->open)
1567 new->vm_ops->open(new);
1568
1569 delete_vma_from_mm(vma);
1570 down_write(&nommu_region_sem);
1571 delete_nommu_region(vma->vm_region);
1572 if (new_below) {
1573 vma->vm_region->vm_start = vma->vm_start = addr;
1574 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1575 } else {
1576 vma->vm_region->vm_end = vma->vm_end = addr;
1577 vma->vm_region->vm_top = addr;
1578 }
1579 add_nommu_region(vma->vm_region);
1580 add_nommu_region(new->vm_region);
1581 up_write(&nommu_region_sem);
1582 add_vma_to_mm(mm, vma);
1583 add_vma_to_mm(mm, new);
1584 return 0;
1585}
1586
1587/*
1588 * shrink a VMA by removing the specified chunk from either the beginning or
1589 * the end
1590 */
1591static int shrink_vma(struct mm_struct *mm,
1592 struct vm_area_struct *vma,
1593 unsigned long from, unsigned long to)
1594{
1595 struct vm_region *region;
1596
1597 kenter("");
1598
1599 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1600 * and list */
1601 delete_vma_from_mm(vma);
1602 if (from > vma->vm_start)
1603 vma->vm_end = from;
1604 else
1605 vma->vm_start = to;
1606 add_vma_to_mm(mm, vma);
1607
1608 /* cut the backing region down to size */
1609 region = vma->vm_region;
1610 BUG_ON(region->vm_usage != 1);
1611
1612 down_write(&nommu_region_sem);
1613 delete_nommu_region(region);
1614 if (from > region->vm_start) {
1615 to = region->vm_top;
1616 region->vm_top = region->vm_end = from;
1617 } else {
1618 region->vm_start = to;
1619 }
1620 add_nommu_region(region);
1621 up_write(&nommu_region_sem);
1622
1623 free_page_series(from, to);
1624 return 0;
1625}
1626
1627/*
1628 * release a mapping
1629 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1630 * VMA, though it need not cover the whole VMA
1631 */
1632int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1633{
1634 struct vm_area_struct *vma;
1635 unsigned long end;
1636 int ret;
1637
1638 kenter(",%lx,%zx", start, len);
1639
1640 len = PAGE_ALIGN(len);
1641 if (len == 0)
1642 return -EINVAL;
1643
1644 end = start + len;
1645
1646 /* find the first potentially overlapping VMA */
1647 vma = find_vma(mm, start);
1648 if (!vma) {
1649 static int limit = 0;
1650 if (limit < 5) {
1651 printk(KERN_WARNING
1652 "munmap of memory not mmapped by process %d"
1653 " (%s): 0x%lx-0x%lx\n",
1654 current->pid, current->comm,
1655 start, start + len - 1);
1656 limit++;
1657 }
1658 return -EINVAL;
1659 }
1660
1661 /* we're allowed to split an anonymous VMA but not a file-backed one */
1662 if (vma->vm_file) {
1663 do {
1664 if (start > vma->vm_start) {
1665 kleave(" = -EINVAL [miss]");
1666 return -EINVAL;
1667 }
1668 if (end == vma->vm_end)
1669 goto erase_whole_vma;
1670 vma = vma->vm_next;
1671 } while (vma);
1672 kleave(" = -EINVAL [split file]");
1673 return -EINVAL;
1674 } else {
1675 /* the chunk must be a subset of the VMA found */
1676 if (start == vma->vm_start && end == vma->vm_end)
1677 goto erase_whole_vma;
1678 if (start < vma->vm_start || end > vma->vm_end) {
1679 kleave(" = -EINVAL [superset]");
1680 return -EINVAL;
1681 }
1682 if (start & ~PAGE_MASK) {
1683 kleave(" = -EINVAL [unaligned start]");
1684 return -EINVAL;
1685 }
1686 if (end != vma->vm_end && end & ~PAGE_MASK) {
1687 kleave(" = -EINVAL [unaligned split]");
1688 return -EINVAL;
1689 }
1690 if (start != vma->vm_start && end != vma->vm_end) {
1691 ret = split_vma(mm, vma, start, 1);
1692 if (ret < 0) {
1693 kleave(" = %d [split]", ret);
1694 return ret;
1695 }
1696 }
1697 return shrink_vma(mm, vma, start, end);
1698 }
1699
1700erase_whole_vma:
1701 delete_vma_from_mm(vma);
1702 delete_vma(mm, vma);
1703 kleave(" = 0");
1704 return 0;
1705}
1706EXPORT_SYMBOL(do_munmap);
1707
1708int vm_munmap(unsigned long addr, size_t len)
1709{
1710 struct mm_struct *mm = current->mm;
1711 int ret;
1712
1713 down_write(&mm->mmap_sem);
1714 ret = do_munmap(mm, addr, len);
1715 up_write(&mm->mmap_sem);
1716 return ret;
1717}
1718EXPORT_SYMBOL(vm_munmap);
1719
1720SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1721{
1722 return vm_munmap(addr, len);
1723}
1724
1725/*
1726 * release all the mappings made in a process's VM space
1727 */
1728void exit_mmap(struct mm_struct *mm)
1729{
1730 struct vm_area_struct *vma;
1731
1732 if (!mm)
1733 return;
1734
1735 kenter("");
1736
1737 mm->total_vm = 0;
1738
1739 while ((vma = mm->mmap)) {
1740 mm->mmap = vma->vm_next;
1741 delete_vma_from_mm(vma);
1742 delete_vma(mm, vma);
1743 cond_resched();
1744 }
1745
1746 kleave("");
1747}
1748
1749unsigned long vm_brk(unsigned long addr, unsigned long len)
1750{
1751 return -ENOMEM;
1752}
1753
1754/*
1755 * expand (or shrink) an existing mapping, potentially moving it at the same
1756 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1757 *
1758 * under NOMMU conditions, we only permit changing a mapping's size, and only
1759 * as long as it stays within the region allocated by do_mmap_private() and the
1760 * block is not shareable
1761 *
1762 * MREMAP_FIXED is not supported under NOMMU conditions
1763 */
1764unsigned long do_mremap(unsigned long addr,
1765 unsigned long old_len, unsigned long new_len,
1766 unsigned long flags, unsigned long new_addr)
1767{
1768 struct vm_area_struct *vma;
1769
1770 /* insanity checks first */
1771 old_len = PAGE_ALIGN(old_len);
1772 new_len = PAGE_ALIGN(new_len);
1773 if (old_len == 0 || new_len == 0)
1774 return (unsigned long) -EINVAL;
1775
1776 if (addr & ~PAGE_MASK)
1777 return -EINVAL;
1778
1779 if (flags & MREMAP_FIXED && new_addr != addr)
1780 return (unsigned long) -EINVAL;
1781
1782 vma = find_vma_exact(current->mm, addr, old_len);
1783 if (!vma)
1784 return (unsigned long) -EINVAL;
1785
1786 if (vma->vm_end != vma->vm_start + old_len)
1787 return (unsigned long) -EFAULT;
1788
1789 if (vma->vm_flags & VM_MAYSHARE)
1790 return (unsigned long) -EPERM;
1791
1792 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1793 return (unsigned long) -ENOMEM;
1794
1795 /* all checks complete - do it */
1796 vma->vm_end = vma->vm_start + new_len;
1797 return vma->vm_start;
1798}
1799EXPORT_SYMBOL(do_mremap);
1800
1801SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1802 unsigned long, new_len, unsigned long, flags,
1803 unsigned long, new_addr)
1804{
1805 unsigned long ret;
1806
1807 down_write(¤t->mm->mmap_sem);
1808 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1809 up_write(¤t->mm->mmap_sem);
1810 return ret;
1811}
1812
1813struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1814 unsigned int foll_flags)
1815{
1816 return NULL;
1817}
1818
1819int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1820 unsigned long pfn, unsigned long size, pgprot_t prot)
1821{
1822 if (addr != (pfn << PAGE_SHIFT))
1823 return -EINVAL;
1824
1825 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
1826 return 0;
1827}
1828EXPORT_SYMBOL(remap_pfn_range);
1829
1830int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1831 unsigned long pgoff)
1832{
1833 unsigned int size = vma->vm_end - vma->vm_start;
1834
1835 if (!(vma->vm_flags & VM_USERMAP))
1836 return -EINVAL;
1837
1838 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1839 vma->vm_end = vma->vm_start + size;
1840
1841 return 0;
1842}
1843EXPORT_SYMBOL(remap_vmalloc_range);
1844
1845unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1846 unsigned long len, unsigned long pgoff, unsigned long flags)
1847{
1848 return -ENOMEM;
1849}
1850
1851void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1852{
1853}
1854
1855void unmap_mapping_range(struct address_space *mapping,
1856 loff_t const holebegin, loff_t const holelen,
1857 int even_cows)
1858{
1859}
1860EXPORT_SYMBOL(unmap_mapping_range);
1861
1862/*
1863 * Check that a process has enough memory to allocate a new virtual
1864 * mapping. 0 means there is enough memory for the allocation to
1865 * succeed and -ENOMEM implies there is not.
1866 *
1867 * We currently support three overcommit policies, which are set via the
1868 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1869 *
1870 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1871 * Additional code 2002 Jul 20 by Robert Love.
1872 *
1873 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1874 *
1875 * Note this is a helper function intended to be used by LSMs which
1876 * wish to use this logic.
1877 */
1878int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1879{
1880 unsigned long free, allowed;
1881
1882 vm_acct_memory(pages);
1883
1884 /*
1885 * Sometimes we want to use more memory than we have
1886 */
1887 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1888 return 0;
1889
1890 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1891 free = global_page_state(NR_FREE_PAGES);
1892 free += global_page_state(NR_FILE_PAGES);
1893
1894 /*
1895 * shmem pages shouldn't be counted as free in this
1896 * case, they can't be purged, only swapped out, and
1897 * that won't affect the overall amount of available
1898 * memory in the system.
1899 */
1900 free -= global_page_state(NR_SHMEM);
1901
1902 free += nr_swap_pages;
1903
1904 /*
1905 * Any slabs which are created with the
1906 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1907 * which are reclaimable, under pressure. The dentry
1908 * cache and most inode caches should fall into this
1909 */
1910 free += global_page_state(NR_SLAB_RECLAIMABLE);
1911
1912 /*
1913 * Leave reserved pages. The pages are not for anonymous pages.
1914 */
1915 if (free <= totalreserve_pages)
1916 goto error;
1917 else
1918 free -= totalreserve_pages;
1919
1920 /*
1921 * Leave the last 3% for root
1922 */
1923 if (!cap_sys_admin)
1924 free -= free / 32;
1925
1926 if (free > pages)
1927 return 0;
1928
1929 goto error;
1930 }
1931
1932 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1933 /*
1934 * Leave the last 3% for root
1935 */
1936 if (!cap_sys_admin)
1937 allowed -= allowed / 32;
1938 allowed += total_swap_pages;
1939
1940 /* Don't let a single process grow too big:
1941 leave 3% of the size of this process for other processes */
1942 if (mm)
1943 allowed -= mm->total_vm / 32;
1944
1945 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1946 return 0;
1947
1948error:
1949 vm_unacct_memory(pages);
1950
1951 return -ENOMEM;
1952}
1953
1954int in_gate_area_no_mm(unsigned long addr)
1955{
1956 return 0;
1957}
1958
1959int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1960{
1961 BUG();
1962 return 0;
1963}
1964EXPORT_SYMBOL(filemap_fault);
1965
1966static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1967 unsigned long addr, void *buf, int len, int write)
1968{
1969 struct vm_area_struct *vma;
1970
1971 down_read(&mm->mmap_sem);
1972
1973 /* the access must start within one of the target process's mappings */
1974 vma = find_vma(mm, addr);
1975 if (vma) {
1976 /* don't overrun this mapping */
1977 if (addr + len >= vma->vm_end)
1978 len = vma->vm_end - addr;
1979
1980 /* only read or write mappings where it is permitted */
1981 if (write && vma->vm_flags & VM_MAYWRITE)
1982 copy_to_user_page(vma, NULL, addr,
1983 (void *) addr, buf, len);
1984 else if (!write && vma->vm_flags & VM_MAYREAD)
1985 copy_from_user_page(vma, NULL, addr,
1986 buf, (void *) addr, len);
1987 else
1988 len = 0;
1989 } else {
1990 len = 0;
1991 }
1992
1993 up_read(&mm->mmap_sem);
1994
1995 return len;
1996}
1997
1998/**
1999 * @access_remote_vm - access another process' address space
2000 * @mm: the mm_struct of the target address space
2001 * @addr: start address to access
2002 * @buf: source or destination buffer
2003 * @len: number of bytes to transfer
2004 * @write: whether the access is a write
2005 *
2006 * The caller must hold a reference on @mm.
2007 */
2008int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2009 void *buf, int len, int write)
2010{
2011 return __access_remote_vm(NULL, mm, addr, buf, len, write);
2012}
2013
2014/*
2015 * Access another process' address space.
2016 * - source/target buffer must be kernel space
2017 */
2018int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2019{
2020 struct mm_struct *mm;
2021
2022 if (addr + len < addr)
2023 return 0;
2024
2025 mm = get_task_mm(tsk);
2026 if (!mm)
2027 return 0;
2028
2029 len = __access_remote_vm(tsk, mm, addr, buf, len, write);
2030
2031 mmput(mm);
2032 return len;
2033}
2034
2035/**
2036 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
2037 * @inode: The inode to check
2038 * @size: The current filesize of the inode
2039 * @newsize: The proposed filesize of the inode
2040 *
2041 * Check the shared mappings on an inode on behalf of a shrinking truncate to
2042 * make sure that that any outstanding VMAs aren't broken and then shrink the
2043 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
2044 * automatically grant mappings that are too large.
2045 */
2046int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
2047 size_t newsize)
2048{
2049 struct vm_area_struct *vma;
2050 struct prio_tree_iter iter;
2051 struct vm_region *region;
2052 pgoff_t low, high;
2053 size_t r_size, r_top;
2054
2055 low = newsize >> PAGE_SHIFT;
2056 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2057
2058 down_write(&nommu_region_sem);
2059 mutex_lock(&inode->i_mapping->i_mmap_mutex);
2060
2061 /* search for VMAs that fall within the dead zone */
2062 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
2063 low, high) {
2064 /* found one - only interested if it's shared out of the page
2065 * cache */
2066 if (vma->vm_flags & VM_SHARED) {
2067 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
2068 up_write(&nommu_region_sem);
2069 return -ETXTBSY; /* not quite true, but near enough */
2070 }
2071 }
2072
2073 /* reduce any regions that overlap the dead zone - if in existence,
2074 * these will be pointed to by VMAs that don't overlap the dead zone
2075 *
2076 * we don't check for any regions that start beyond the EOF as there
2077 * shouldn't be any
2078 */
2079 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
2080 0, ULONG_MAX) {
2081 if (!(vma->vm_flags & VM_SHARED))
2082 continue;
2083
2084 region = vma->vm_region;
2085 r_size = region->vm_top - region->vm_start;
2086 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
2087
2088 if (r_top > newsize) {
2089 region->vm_top -= r_top - newsize;
2090 if (region->vm_end > region->vm_top)
2091 region->vm_end = region->vm_top;
2092 }
2093 }
2094
2095 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
2096 up_write(&nommu_region_sem);
2097 return 0;
2098}