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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#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}