net: ipv6 bind to device issue
[linux-2.6-block.git] / mm / nommu.c
CommitLineData
1da177e4
LT
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 *
8feae131 9 * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
1da177e4
LT
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>
eb6434d9 13 * Copyright (c) 2007-2009 Paul Mundt <lethal@linux-sh.org>
1da177e4
LT
14 */
15
f2b8544f 16#include <linux/module.h>
1da177e4
LT
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>
fa8e26cc 25#include <linux/tracehook.h>
1da177e4
LT
26#include <linux/blkdev.h>
27#include <linux/backing-dev.h>
28#include <linux/mount.h>
29#include <linux/personality.h>
30#include <linux/security.h>
31#include <linux/syscalls.h>
32
33#include <asm/uaccess.h>
34#include <asm/tlb.h>
35#include <asm/tlbflush.h>
eb8cdec4 36#include <asm/mmu_context.h>
8feae131
DH
37#include "internal.h"
38
39static inline __attribute__((format(printf, 1, 2)))
40void no_printk(const char *fmt, ...)
41{
42}
43
44#if 0
45#define kenter(FMT, ...) \
46 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
47#define kleave(FMT, ...) \
48 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
49#define kdebug(FMT, ...) \
50 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
51#else
52#define kenter(FMT, ...) \
53 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
54#define kleave(FMT, ...) \
55 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
56#define kdebug(FMT, ...) \
57 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
58#endif
1da177e4
LT
59
60void *high_memory;
61struct page *mem_map;
62unsigned long max_mapnr;
63unsigned long num_physpages;
4266c97a 64unsigned long highest_memmap_pfn;
00a62ce9 65struct percpu_counter vm_committed_as;
1da177e4
LT
66int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
67int sysctl_overcommit_ratio = 50; /* default is 50% */
68int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
fc4d5c29 69int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
1da177e4
LT
70int heap_stack_gap = 0;
71
33e5d769 72atomic_long_t mmap_pages_allocated;
8feae131 73
1da177e4 74EXPORT_SYMBOL(mem_map);
6a04de6d 75EXPORT_SYMBOL(num_physpages);
1da177e4 76
8feae131
DH
77/* list of mapped, potentially shareable regions */
78static struct kmem_cache *vm_region_jar;
79struct rb_root nommu_region_tree = RB_ROOT;
80DECLARE_RWSEM(nommu_region_sem);
1da177e4 81
f0f37e2f 82const struct vm_operations_struct generic_file_vm_ops = {
1da177e4
LT
83};
84
1da177e4
LT
85/*
86 * Return the total memory allocated for this pointer, not
87 * just what the caller asked for.
88 *
89 * Doesn't have to be accurate, i.e. may have races.
90 */
91unsigned int kobjsize(const void *objp)
92{
93 struct page *page;
94
4016a139
MH
95 /*
96 * If the object we have should not have ksize performed on it,
97 * return size of 0
98 */
5a1603be 99 if (!objp || !virt_addr_valid(objp))
6cfd53fc
PM
100 return 0;
101
102 page = virt_to_head_page(objp);
6cfd53fc
PM
103
104 /*
105 * If the allocator sets PageSlab, we know the pointer came from
106 * kmalloc().
107 */
1da177e4
LT
108 if (PageSlab(page))
109 return ksize(objp);
110
ab2e83ea
PM
111 /*
112 * If it's not a compound page, see if we have a matching VMA
113 * region. This test is intentionally done in reverse order,
114 * so if there's no VMA, we still fall through and hand back
115 * PAGE_SIZE for 0-order pages.
116 */
117 if (!PageCompound(page)) {
118 struct vm_area_struct *vma;
119
120 vma = find_vma(current->mm, (unsigned long)objp);
121 if (vma)
122 return vma->vm_end - vma->vm_start;
123 }
124
6cfd53fc
PM
125 /*
126 * The ksize() function is only guaranteed to work for pointers
5a1603be 127 * returned by kmalloc(). So handle arbitrary pointers here.
6cfd53fc 128 */
5a1603be 129 return PAGE_SIZE << compound_order(page);
1da177e4
LT
130}
131
b291f000 132int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
4266c97a 133 unsigned long start, int nr_pages, unsigned int foll_flags,
9d73777e 134 struct page **pages, struct vm_area_struct **vmas)
1da177e4 135{
910e46da 136 struct vm_area_struct *vma;
7b4d5b8b
DH
137 unsigned long vm_flags;
138 int i;
139
140 /* calculate required read or write permissions.
58fa879e 141 * If FOLL_FORCE is set, we only require the "MAY" flags.
7b4d5b8b 142 */
58fa879e
HD
143 vm_flags = (foll_flags & FOLL_WRITE) ?
144 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
145 vm_flags &= (foll_flags & FOLL_FORCE) ?
146 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1da177e4 147
9d73777e 148 for (i = 0; i < nr_pages; i++) {
7561e8ca 149 vma = find_vma(mm, start);
7b4d5b8b
DH
150 if (!vma)
151 goto finish_or_fault;
152
153 /* protect what we can, including chardevs */
1c3aff1c
HD
154 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
155 !(vm_flags & vma->vm_flags))
7b4d5b8b 156 goto finish_or_fault;
910e46da 157
1da177e4
LT
158 if (pages) {
159 pages[i] = virt_to_page(start);
160 if (pages[i])
161 page_cache_get(pages[i]);
162 }
163 if (vmas)
910e46da 164 vmas[i] = vma;
e1ee65d8 165 start = (start + PAGE_SIZE) & PAGE_MASK;
1da177e4 166 }
7b4d5b8b
DH
167
168 return i;
169
170finish_or_fault:
171 return i ? : -EFAULT;
1da177e4 172}
b291f000 173
b291f000
NP
174/*
175 * get a list of pages in an address range belonging to the specified process
176 * and indicate the VMA that covers each page
177 * - this is potentially dodgy as we may end incrementing the page count of a
178 * slab page or a secondary page from a compound page
179 * - don't permit access to VMAs that don't support it, such as I/O mappings
180 */
181int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
9d73777e 182 unsigned long start, int nr_pages, int write, int force,
b291f000
NP
183 struct page **pages, struct vm_area_struct **vmas)
184{
185 int flags = 0;
186
187 if (write)
58fa879e 188 flags |= FOLL_WRITE;
b291f000 189 if (force)
58fa879e 190 flags |= FOLL_FORCE;
b291f000 191
9d73777e 192 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
b291f000 193}
66aa2b4b
GU
194EXPORT_SYMBOL(get_user_pages);
195
dfc2f91a
PM
196/**
197 * follow_pfn - look up PFN at a user virtual address
198 * @vma: memory mapping
199 * @address: user virtual address
200 * @pfn: location to store found PFN
201 *
202 * Only IO mappings and raw PFN mappings are allowed.
203 *
204 * Returns zero and the pfn at @pfn on success, -ve otherwise.
205 */
206int follow_pfn(struct vm_area_struct *vma, unsigned long address,
207 unsigned long *pfn)
208{
209 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
210 return -EINVAL;
211
212 *pfn = address >> PAGE_SHIFT;
213 return 0;
214}
215EXPORT_SYMBOL(follow_pfn);
216
1da177e4
LT
217DEFINE_RWLOCK(vmlist_lock);
218struct vm_struct *vmlist;
219
b3bdda02 220void vfree(const void *addr)
1da177e4
LT
221{
222 kfree(addr);
223}
b5073173 224EXPORT_SYMBOL(vfree);
1da177e4 225
dd0fc66f 226void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
1da177e4
LT
227{
228 /*
8518609d
RD
229 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
230 * returns only a logical address.
1da177e4 231 */
84097518 232 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
1da177e4 233}
b5073173 234EXPORT_SYMBOL(__vmalloc);
1da177e4 235
f905bc44
PM
236void *vmalloc_user(unsigned long size)
237{
238 void *ret;
239
240 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
241 PAGE_KERNEL);
242 if (ret) {
243 struct vm_area_struct *vma;
244
245 down_write(&current->mm->mmap_sem);
246 vma = find_vma(current->mm, (unsigned long)ret);
247 if (vma)
248 vma->vm_flags |= VM_USERMAP;
249 up_write(&current->mm->mmap_sem);
250 }
251
252 return ret;
253}
254EXPORT_SYMBOL(vmalloc_user);
255
b3bdda02 256struct page *vmalloc_to_page(const void *addr)
1da177e4
LT
257{
258 return virt_to_page(addr);
259}
b5073173 260EXPORT_SYMBOL(vmalloc_to_page);
1da177e4 261
b3bdda02 262unsigned long vmalloc_to_pfn(const void *addr)
1da177e4
LT
263{
264 return page_to_pfn(virt_to_page(addr));
265}
b5073173 266EXPORT_SYMBOL(vmalloc_to_pfn);
1da177e4
LT
267
268long vread(char *buf, char *addr, unsigned long count)
269{
270 memcpy(buf, addr, count);
271 return count;
272}
273
274long vwrite(char *buf, char *addr, unsigned long count)
275{
276 /* Don't allow overflow */
277 if ((unsigned long) addr + count < count)
278 count = -(unsigned long) addr;
279
280 memcpy(addr, buf, count);
281 return(count);
282}
283
284/*
285 * vmalloc - allocate virtually continguos memory
286 *
287 * @size: allocation size
288 *
289 * Allocate enough pages to cover @size from the page level
290 * allocator and map them into continguos kernel virtual space.
291 *
c1c8897f 292 * For tight control over page level allocator and protection flags
1da177e4
LT
293 * use __vmalloc() instead.
294 */
295void *vmalloc(unsigned long size)
296{
297 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
298}
f6138882
AM
299EXPORT_SYMBOL(vmalloc);
300
301void *vmalloc_node(unsigned long size, int node)
302{
303 return vmalloc(size);
304}
305EXPORT_SYMBOL(vmalloc_node);
1da177e4 306
1af446ed
PM
307#ifndef PAGE_KERNEL_EXEC
308# define PAGE_KERNEL_EXEC PAGE_KERNEL
309#endif
310
311/**
312 * vmalloc_exec - allocate virtually contiguous, executable memory
313 * @size: allocation size
314 *
315 * Kernel-internal function to allocate enough pages to cover @size
316 * the page level allocator and map them into contiguous and
317 * executable kernel virtual space.
318 *
319 * For tight control over page level allocator and protection flags
320 * use __vmalloc() instead.
321 */
322
323void *vmalloc_exec(unsigned long size)
324{
325 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
326}
327
b5073173
PM
328/**
329 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
1da177e4
LT
330 * @size: allocation size
331 *
332 * Allocate enough 32bit PA addressable pages to cover @size from the
333 * page level allocator and map them into continguos kernel virtual space.
334 */
335void *vmalloc_32(unsigned long size)
336{
337 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
338}
b5073173
PM
339EXPORT_SYMBOL(vmalloc_32);
340
341/**
342 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
343 * @size: allocation size
344 *
345 * The resulting memory area is 32bit addressable and zeroed so it can be
346 * mapped to userspace without leaking data.
f905bc44
PM
347 *
348 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
349 * remap_vmalloc_range() are permissible.
b5073173
PM
350 */
351void *vmalloc_32_user(unsigned long size)
352{
f905bc44
PM
353 /*
354 * We'll have to sort out the ZONE_DMA bits for 64-bit,
355 * but for now this can simply use vmalloc_user() directly.
356 */
357 return vmalloc_user(size);
b5073173
PM
358}
359EXPORT_SYMBOL(vmalloc_32_user);
1da177e4
LT
360
361void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
362{
363 BUG();
364 return NULL;
365}
b5073173 366EXPORT_SYMBOL(vmap);
1da177e4 367
b3bdda02 368void vunmap(const void *addr)
1da177e4
LT
369{
370 BUG();
371}
b5073173 372EXPORT_SYMBOL(vunmap);
1da177e4 373
eb6434d9
PM
374void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
375{
376 BUG();
377 return NULL;
378}
379EXPORT_SYMBOL(vm_map_ram);
380
381void vm_unmap_ram(const void *mem, unsigned int count)
382{
383 BUG();
384}
385EXPORT_SYMBOL(vm_unmap_ram);
386
387void vm_unmap_aliases(void)
388{
389}
390EXPORT_SYMBOL_GPL(vm_unmap_aliases);
391
1eeb66a1
CH
392/*
393 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
394 * have one.
395 */
396void __attribute__((weak)) vmalloc_sync_all(void)
397{
398}
399
b5073173
PM
400int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
401 struct page *page)
402{
403 return -EINVAL;
404}
405EXPORT_SYMBOL(vm_insert_page);
406
1da177e4
LT
407/*
408 * sys_brk() for the most part doesn't need the global kernel
409 * lock, except when an application is doing something nasty
410 * like trying to un-brk an area that has already been mapped
411 * to a regular file. in this case, the unmapping will need
412 * to invoke file system routines that need the global lock.
413 */
6a6160a7 414SYSCALL_DEFINE1(brk, unsigned long, brk)
1da177e4
LT
415{
416 struct mm_struct *mm = current->mm;
417
418 if (brk < mm->start_brk || brk > mm->context.end_brk)
419 return mm->brk;
420
421 if (mm->brk == brk)
422 return mm->brk;
423
424 /*
425 * Always allow shrinking brk
426 */
427 if (brk <= mm->brk) {
428 mm->brk = brk;
429 return brk;
430 }
431
432 /*
433 * Ok, looks good - let it rip.
434 */
cfe79c00 435 flush_icache_range(mm->brk, brk);
1da177e4
LT
436 return mm->brk = brk;
437}
438
8feae131
DH
439/*
440 * initialise the VMA and region record slabs
441 */
442void __init mmap_init(void)
1da177e4 443{
00a62ce9
KM
444 int ret;
445
446 ret = percpu_counter_init(&vm_committed_as, 0);
447 VM_BUG_ON(ret);
33e5d769 448 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
1da177e4 449}
1da177e4 450
3034097a 451/*
8feae131
DH
452 * validate the region tree
453 * - the caller must hold the region lock
3034097a 454 */
8feae131
DH
455#ifdef CONFIG_DEBUG_NOMMU_REGIONS
456static noinline void validate_nommu_regions(void)
3034097a 457{
8feae131
DH
458 struct vm_region *region, *last;
459 struct rb_node *p, *lastp;
3034097a 460
8feae131
DH
461 lastp = rb_first(&nommu_region_tree);
462 if (!lastp)
463 return;
464
465 last = rb_entry(lastp, struct vm_region, vm_rb);
33e5d769
DH
466 BUG_ON(unlikely(last->vm_end <= last->vm_start));
467 BUG_ON(unlikely(last->vm_top < last->vm_end));
8feae131
DH
468
469 while ((p = rb_next(lastp))) {
470 region = rb_entry(p, struct vm_region, vm_rb);
471 last = rb_entry(lastp, struct vm_region, vm_rb);
472
33e5d769
DH
473 BUG_ON(unlikely(region->vm_end <= region->vm_start));
474 BUG_ON(unlikely(region->vm_top < region->vm_end));
475 BUG_ON(unlikely(region->vm_start < last->vm_top));
3034097a 476
8feae131
DH
477 lastp = p;
478 }
3034097a 479}
8feae131 480#else
33e5d769
DH
481static void validate_nommu_regions(void)
482{
483}
8feae131 484#endif
3034097a
DH
485
486/*
8feae131 487 * add a region into the global tree
3034097a 488 */
8feae131 489static void add_nommu_region(struct vm_region *region)
3034097a 490{
8feae131
DH
491 struct vm_region *pregion;
492 struct rb_node **p, *parent;
3034097a 493
8feae131
DH
494 validate_nommu_regions();
495
8feae131
DH
496 parent = NULL;
497 p = &nommu_region_tree.rb_node;
498 while (*p) {
499 parent = *p;
500 pregion = rb_entry(parent, struct vm_region, vm_rb);
501 if (region->vm_start < pregion->vm_start)
502 p = &(*p)->rb_left;
503 else if (region->vm_start > pregion->vm_start)
504 p = &(*p)->rb_right;
505 else if (pregion == region)
506 return;
507 else
508 BUG();
3034097a
DH
509 }
510
8feae131
DH
511 rb_link_node(&region->vm_rb, parent, p);
512 rb_insert_color(&region->vm_rb, &nommu_region_tree);
3034097a 513
8feae131 514 validate_nommu_regions();
3034097a 515}
3034097a 516
930e652a 517/*
8feae131 518 * delete a region from the global tree
930e652a 519 */
8feae131 520static void delete_nommu_region(struct vm_region *region)
930e652a 521{
8feae131 522 BUG_ON(!nommu_region_tree.rb_node);
930e652a 523
8feae131
DH
524 validate_nommu_regions();
525 rb_erase(&region->vm_rb, &nommu_region_tree);
526 validate_nommu_regions();
57c8f63e
GU
527}
528
6fa5f80b 529/*
8feae131 530 * free a contiguous series of pages
6fa5f80b 531 */
8feae131 532static void free_page_series(unsigned long from, unsigned long to)
6fa5f80b 533{
8feae131
DH
534 for (; from < to; from += PAGE_SIZE) {
535 struct page *page = virt_to_page(from);
536
537 kdebug("- free %lx", from);
33e5d769 538 atomic_long_dec(&mmap_pages_allocated);
8feae131 539 if (page_count(page) != 1)
33e5d769
DH
540 kdebug("free page %p: refcount not one: %d",
541 page, page_count(page));
8feae131 542 put_page(page);
6fa5f80b 543 }
6fa5f80b
DH
544}
545
3034097a 546/*
8feae131 547 * release a reference to a region
33e5d769 548 * - the caller must hold the region semaphore for writing, which this releases
dd8632a1 549 * - the region may not have been added to the tree yet, in which case vm_top
8feae131 550 * will equal vm_start
3034097a 551 */
8feae131
DH
552static void __put_nommu_region(struct vm_region *region)
553 __releases(nommu_region_sem)
1da177e4 554{
1e2ae599 555 kenter("%p{%d}", region, region->vm_usage);
1da177e4 556
8feae131 557 BUG_ON(!nommu_region_tree.rb_node);
1da177e4 558
1e2ae599 559 if (--region->vm_usage == 0) {
dd8632a1 560 if (region->vm_top > region->vm_start)
8feae131
DH
561 delete_nommu_region(region);
562 up_write(&nommu_region_sem);
563
564 if (region->vm_file)
565 fput(region->vm_file);
566
567 /* IO memory and memory shared directly out of the pagecache
568 * from ramfs/tmpfs mustn't be released here */
569 if (region->vm_flags & VM_MAPPED_COPY) {
570 kdebug("free series");
dd8632a1 571 free_page_series(region->vm_start, region->vm_top);
8feae131
DH
572 }
573 kmem_cache_free(vm_region_jar, region);
574 } else {
575 up_write(&nommu_region_sem);
1da177e4 576 }
8feae131 577}
1da177e4 578
8feae131
DH
579/*
580 * release a reference to a region
581 */
582static void put_nommu_region(struct vm_region *region)
583{
584 down_write(&nommu_region_sem);
585 __put_nommu_region(region);
1da177e4
LT
586}
587
eb8cdec4
BS
588/*
589 * update protection on a vma
590 */
591static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
592{
593#ifdef CONFIG_MPU
594 struct mm_struct *mm = vma->vm_mm;
595 long start = vma->vm_start & PAGE_MASK;
596 while (start < vma->vm_end) {
597 protect_page(mm, start, flags);
598 start += PAGE_SIZE;
599 }
600 update_protections(mm);
601#endif
602}
603
3034097a 604/*
8feae131
DH
605 * add a VMA into a process's mm_struct in the appropriate place in the list
606 * and tree and add to the address space's page tree also if not an anonymous
607 * page
608 * - should be called with mm->mmap_sem held writelocked
3034097a 609 */
8feae131 610static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
1da177e4 611{
8feae131 612 struct vm_area_struct *pvma, **pp;
1da177e4 613 struct address_space *mapping;
8feae131
DH
614 struct rb_node **p, *parent;
615
616 kenter(",%p", vma);
617
618 BUG_ON(!vma->vm_region);
619
620 mm->map_count++;
621 vma->vm_mm = mm;
1da177e4 622
eb8cdec4
BS
623 protect_vma(vma, vma->vm_flags);
624
1da177e4
LT
625 /* add the VMA to the mapping */
626 if (vma->vm_file) {
627 mapping = vma->vm_file->f_mapping;
628
629 flush_dcache_mmap_lock(mapping);
630 vma_prio_tree_insert(vma, &mapping->i_mmap);
631 flush_dcache_mmap_unlock(mapping);
632 }
633
8feae131
DH
634 /* add the VMA to the tree */
635 parent = NULL;
636 p = &mm->mm_rb.rb_node;
1da177e4
LT
637 while (*p) {
638 parent = *p;
639 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
640
8feae131
DH
641 /* sort by: start addr, end addr, VMA struct addr in that order
642 * (the latter is necessary as we may get identical VMAs) */
643 if (vma->vm_start < pvma->vm_start)
1da177e4 644 p = &(*p)->rb_left;
8feae131 645 else if (vma->vm_start > pvma->vm_start)
1da177e4 646 p = &(*p)->rb_right;
8feae131
DH
647 else if (vma->vm_end < pvma->vm_end)
648 p = &(*p)->rb_left;
649 else if (vma->vm_end > pvma->vm_end)
650 p = &(*p)->rb_right;
651 else if (vma < pvma)
652 p = &(*p)->rb_left;
653 else if (vma > pvma)
654 p = &(*p)->rb_right;
655 else
656 BUG();
1da177e4
LT
657 }
658
659 rb_link_node(&vma->vm_rb, parent, p);
8feae131
DH
660 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
661
662 /* add VMA to the VMA list also */
663 for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
664 if (pvma->vm_start > vma->vm_start)
665 break;
666 if (pvma->vm_start < vma->vm_start)
667 continue;
668 if (pvma->vm_end < vma->vm_end)
669 break;
670 }
671
672 vma->vm_next = *pp;
673 *pp = vma;
1da177e4
LT
674}
675
3034097a 676/*
8feae131 677 * delete a VMA from its owning mm_struct and address space
3034097a 678 */
8feae131 679static void delete_vma_from_mm(struct vm_area_struct *vma)
1da177e4 680{
8feae131 681 struct vm_area_struct **pp;
1da177e4 682 struct address_space *mapping;
8feae131
DH
683 struct mm_struct *mm = vma->vm_mm;
684
685 kenter("%p", vma);
686
eb8cdec4
BS
687 protect_vma(vma, 0);
688
8feae131
DH
689 mm->map_count--;
690 if (mm->mmap_cache == vma)
691 mm->mmap_cache = NULL;
1da177e4
LT
692
693 /* remove the VMA from the mapping */
694 if (vma->vm_file) {
695 mapping = vma->vm_file->f_mapping;
696
697 flush_dcache_mmap_lock(mapping);
698 vma_prio_tree_remove(vma, &mapping->i_mmap);
699 flush_dcache_mmap_unlock(mapping);
700 }
701
8feae131
DH
702 /* remove from the MM's tree and list */
703 rb_erase(&vma->vm_rb, &mm->mm_rb);
704 for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
705 if (*pp == vma) {
706 *pp = vma->vm_next;
707 break;
708 }
709 }
710
711 vma->vm_mm = NULL;
712}
713
714/*
715 * destroy a VMA record
716 */
717static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
718{
719 kenter("%p", vma);
720 if (vma->vm_ops && vma->vm_ops->close)
721 vma->vm_ops->close(vma);
722 if (vma->vm_file) {
723 fput(vma->vm_file);
724 if (vma->vm_flags & VM_EXECUTABLE)
725 removed_exe_file_vma(mm);
726 }
727 put_nommu_region(vma->vm_region);
728 kmem_cache_free(vm_area_cachep, vma);
729}
730
731/*
732 * look up the first VMA in which addr resides, NULL if none
733 * - should be called with mm->mmap_sem at least held readlocked
734 */
735struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
736{
737 struct vm_area_struct *vma;
738 struct rb_node *n = mm->mm_rb.rb_node;
739
740 /* check the cache first */
741 vma = mm->mmap_cache;
742 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
743 return vma;
744
745 /* trawl the tree (there may be multiple mappings in which addr
746 * resides) */
747 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
748 vma = rb_entry(n, struct vm_area_struct, vm_rb);
749 if (vma->vm_start > addr)
750 return NULL;
751 if (vma->vm_end > addr) {
752 mm->mmap_cache = vma;
753 return vma;
754 }
755 }
756
757 return NULL;
758}
759EXPORT_SYMBOL(find_vma);
760
761/*
762 * find a VMA
763 * - we don't extend stack VMAs under NOMMU conditions
764 */
765struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
766{
7561e8ca 767 return find_vma(mm, addr);
8feae131
DH
768}
769
770/*
771 * expand a stack to a given address
772 * - not supported under NOMMU conditions
773 */
774int expand_stack(struct vm_area_struct *vma, unsigned long address)
775{
776 return -ENOMEM;
777}
778
779/*
780 * look up the first VMA exactly that exactly matches addr
781 * - should be called with mm->mmap_sem at least held readlocked
782 */
783static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
784 unsigned long addr,
785 unsigned long len)
786{
787 struct vm_area_struct *vma;
788 struct rb_node *n = mm->mm_rb.rb_node;
789 unsigned long end = addr + len;
790
791 /* check the cache first */
792 vma = mm->mmap_cache;
793 if (vma && vma->vm_start == addr && vma->vm_end == end)
794 return vma;
795
796 /* trawl the tree (there may be multiple mappings in which addr
797 * resides) */
798 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
799 vma = rb_entry(n, struct vm_area_struct, vm_rb);
800 if (vma->vm_start < addr)
801 continue;
802 if (vma->vm_start > addr)
803 return NULL;
804 if (vma->vm_end == end) {
805 mm->mmap_cache = vma;
806 return vma;
807 }
808 }
809
810 return NULL;
1da177e4
LT
811}
812
813/*
814 * determine whether a mapping should be permitted and, if so, what sort of
815 * mapping we're capable of supporting
816 */
817static int validate_mmap_request(struct file *file,
818 unsigned long addr,
819 unsigned long len,
820 unsigned long prot,
821 unsigned long flags,
822 unsigned long pgoff,
823 unsigned long *_capabilities)
824{
8feae131 825 unsigned long capabilities, rlen;
1da177e4
LT
826 unsigned long reqprot = prot;
827 int ret;
828
829 /* do the simple checks first */
06aab5a3 830 if (flags & MAP_FIXED) {
1da177e4
LT
831 printk(KERN_DEBUG
832 "%d: Can't do fixed-address/overlay mmap of RAM\n",
833 current->pid);
834 return -EINVAL;
835 }
836
837 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
838 (flags & MAP_TYPE) != MAP_SHARED)
839 return -EINVAL;
840
f81cff0d 841 if (!len)
1da177e4
LT
842 return -EINVAL;
843
f81cff0d 844 /* Careful about overflows.. */
8feae131
DH
845 rlen = PAGE_ALIGN(len);
846 if (!rlen || rlen > TASK_SIZE)
f81cff0d
MF
847 return -ENOMEM;
848
1da177e4 849 /* offset overflow? */
8feae131 850 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
f81cff0d 851 return -EOVERFLOW;
1da177e4
LT
852
853 if (file) {
854 /* validate file mapping requests */
855 struct address_space *mapping;
856
857 /* files must support mmap */
858 if (!file->f_op || !file->f_op->mmap)
859 return -ENODEV;
860
861 /* work out if what we've got could possibly be shared
862 * - we support chardevs that provide their own "memory"
863 * - we support files/blockdevs that are memory backed
864 */
865 mapping = file->f_mapping;
866 if (!mapping)
e9536ae7 867 mapping = file->f_path.dentry->d_inode->i_mapping;
1da177e4
LT
868
869 capabilities = 0;
870 if (mapping && mapping->backing_dev_info)
871 capabilities = mapping->backing_dev_info->capabilities;
872
873 if (!capabilities) {
874 /* no explicit capabilities set, so assume some
875 * defaults */
e9536ae7 876 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
1da177e4
LT
877 case S_IFREG:
878 case S_IFBLK:
879 capabilities = BDI_CAP_MAP_COPY;
880 break;
881
882 case S_IFCHR:
883 capabilities =
884 BDI_CAP_MAP_DIRECT |
885 BDI_CAP_READ_MAP |
886 BDI_CAP_WRITE_MAP;
887 break;
888
889 default:
890 return -EINVAL;
891 }
892 }
893
894 /* eliminate any capabilities that we can't support on this
895 * device */
896 if (!file->f_op->get_unmapped_area)
897 capabilities &= ~BDI_CAP_MAP_DIRECT;
898 if (!file->f_op->read)
899 capabilities &= ~BDI_CAP_MAP_COPY;
900
28d7a6ae
GY
901 /* The file shall have been opened with read permission. */
902 if (!(file->f_mode & FMODE_READ))
903 return -EACCES;
904
1da177e4
LT
905 if (flags & MAP_SHARED) {
906 /* do checks for writing, appending and locking */
907 if ((prot & PROT_WRITE) &&
908 !(file->f_mode & FMODE_WRITE))
909 return -EACCES;
910
e9536ae7 911 if (IS_APPEND(file->f_path.dentry->d_inode) &&
1da177e4
LT
912 (file->f_mode & FMODE_WRITE))
913 return -EACCES;
914
e9536ae7 915 if (locks_verify_locked(file->f_path.dentry->d_inode))
1da177e4
LT
916 return -EAGAIN;
917
918 if (!(capabilities & BDI_CAP_MAP_DIRECT))
919 return -ENODEV;
920
921 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
922 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
923 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
924 ) {
925 printk("MAP_SHARED not completely supported on !MMU\n");
926 return -EINVAL;
927 }
928
929 /* we mustn't privatise shared mappings */
930 capabilities &= ~BDI_CAP_MAP_COPY;
931 }
932 else {
933 /* we're going to read the file into private memory we
934 * allocate */
935 if (!(capabilities & BDI_CAP_MAP_COPY))
936 return -ENODEV;
937
938 /* we don't permit a private writable mapping to be
939 * shared with the backing device */
940 if (prot & PROT_WRITE)
941 capabilities &= ~BDI_CAP_MAP_DIRECT;
942 }
943
944 /* handle executable mappings and implied executable
945 * mappings */
e9536ae7 946 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
1da177e4
LT
947 if (prot & PROT_EXEC)
948 return -EPERM;
949 }
950 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
951 /* handle implication of PROT_EXEC by PROT_READ */
952 if (current->personality & READ_IMPLIES_EXEC) {
953 if (capabilities & BDI_CAP_EXEC_MAP)
954 prot |= PROT_EXEC;
955 }
956 }
957 else if ((prot & PROT_READ) &&
958 (prot & PROT_EXEC) &&
959 !(capabilities & BDI_CAP_EXEC_MAP)
960 ) {
961 /* backing file is not executable, try to copy */
962 capabilities &= ~BDI_CAP_MAP_DIRECT;
963 }
964 }
965 else {
966 /* anonymous mappings are always memory backed and can be
967 * privately mapped
968 */
969 capabilities = BDI_CAP_MAP_COPY;
970
971 /* handle PROT_EXEC implication by PROT_READ */
972 if ((prot & PROT_READ) &&
973 (current->personality & READ_IMPLIES_EXEC))
974 prot |= PROT_EXEC;
975 }
976
977 /* allow the security API to have its say */
ed032189 978 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
1da177e4
LT
979 if (ret < 0)
980 return ret;
981
982 /* looks okay */
983 *_capabilities = capabilities;
984 return 0;
985}
986
987/*
988 * we've determined that we can make the mapping, now translate what we
989 * now know into VMA flags
990 */
991static unsigned long determine_vm_flags(struct file *file,
992 unsigned long prot,
993 unsigned long flags,
994 unsigned long capabilities)
995{
996 unsigned long vm_flags;
997
998 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
999 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1000 /* vm_flags |= mm->def_flags; */
1001
1002 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1003 /* attempt to share read-only copies of mapped file chunks */
1004 if (file && !(prot & PROT_WRITE))
1005 vm_flags |= VM_MAYSHARE;
1006 }
1007 else {
1008 /* overlay a shareable mapping on the backing device or inode
1009 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1010 * romfs/cramfs */
1011 if (flags & MAP_SHARED)
1012 vm_flags |= VM_MAYSHARE | VM_SHARED;
1013 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1014 vm_flags |= VM_MAYSHARE;
1015 }
1016
1017 /* refuse to let anyone share private mappings with this process if
1018 * it's being traced - otherwise breakpoints set in it may interfere
1019 * with another untraced process
1020 */
fa8e26cc 1021 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
1da177e4
LT
1022 vm_flags &= ~VM_MAYSHARE;
1023
1024 return vm_flags;
1025}
1026
1027/*
8feae131
DH
1028 * set up a shared mapping on a file (the driver or filesystem provides and
1029 * pins the storage)
1da177e4 1030 */
8feae131 1031static int do_mmap_shared_file(struct vm_area_struct *vma)
1da177e4
LT
1032{
1033 int ret;
1034
1035 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
dd8632a1
PM
1036 if (ret == 0) {
1037 vma->vm_region->vm_top = vma->vm_region->vm_end;
645d83c5 1038 return 0;
dd8632a1 1039 }
1da177e4
LT
1040 if (ret != -ENOSYS)
1041 return ret;
1042
3fa30460
DH
1043 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1044 * opposed to tried but failed) so we can only give a suitable error as
1045 * it's not possible to make a private copy if MAP_SHARED was given */
1da177e4
LT
1046 return -ENODEV;
1047}
1048
1049/*
1050 * set up a private mapping or an anonymous shared mapping
1051 */
8feae131
DH
1052static int do_mmap_private(struct vm_area_struct *vma,
1053 struct vm_region *region,
645d83c5
DH
1054 unsigned long len,
1055 unsigned long capabilities)
1da177e4 1056{
8feae131
DH
1057 struct page *pages;
1058 unsigned long total, point, n, rlen;
1da177e4 1059 void *base;
8feae131 1060 int ret, order;
1da177e4
LT
1061
1062 /* invoke the file's mapping function so that it can keep track of
1063 * shared mappings on devices or memory
1064 * - VM_MAYSHARE will be set if it may attempt to share
1065 */
645d83c5 1066 if (capabilities & BDI_CAP_MAP_DIRECT) {
1da177e4 1067 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
dd8632a1 1068 if (ret == 0) {
1da177e4 1069 /* shouldn't return success if we're not sharing */
dd8632a1
PM
1070 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1071 vma->vm_region->vm_top = vma->vm_region->vm_end;
645d83c5 1072 return 0;
1da177e4 1073 }
dd8632a1
PM
1074 if (ret != -ENOSYS)
1075 return ret;
1da177e4
LT
1076
1077 /* getting an ENOSYS error indicates that direct mmap isn't
1078 * possible (as opposed to tried but failed) so we'll try to
1079 * make a private copy of the data and map that instead */
1080 }
1081
8feae131
DH
1082 rlen = PAGE_ALIGN(len);
1083
1da177e4
LT
1084 /* allocate some memory to hold the mapping
1085 * - note that this may not return a page-aligned address if the object
1086 * we're allocating is smaller than a page
1087 */
8feae131
DH
1088 order = get_order(rlen);
1089 kdebug("alloc order %d for %lx", order, len);
1090
1091 pages = alloc_pages(GFP_KERNEL, order);
1092 if (!pages)
1da177e4
LT
1093 goto enomem;
1094
8feae131 1095 total = 1 << order;
33e5d769 1096 atomic_long_add(total, &mmap_pages_allocated);
8feae131
DH
1097
1098 point = rlen >> PAGE_SHIFT;
dd8632a1
PM
1099
1100 /* we allocated a power-of-2 sized page set, so we may want to trim off
1101 * the excess */
1102 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1103 while (total > point) {
1104 order = ilog2(total - point);
1105 n = 1 << order;
1106 kdebug("shave %lu/%lu @%lu", n, total - point, total);
33e5d769 1107 atomic_long_sub(n, &mmap_pages_allocated);
dd8632a1
PM
1108 total -= n;
1109 set_page_refcounted(pages + total);
1110 __free_pages(pages + total, order);
1111 }
8feae131
DH
1112 }
1113
8feae131
DH
1114 for (point = 1; point < total; point++)
1115 set_page_refcounted(&pages[point]);
1da177e4 1116
8feae131
DH
1117 base = page_address(pages);
1118 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1119 region->vm_start = (unsigned long) base;
1120 region->vm_end = region->vm_start + rlen;
dd8632a1 1121 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
8feae131
DH
1122
1123 vma->vm_start = region->vm_start;
1124 vma->vm_end = region->vm_start + len;
1da177e4
LT
1125
1126 if (vma->vm_file) {
1127 /* read the contents of a file into the copy */
1128 mm_segment_t old_fs;
1129 loff_t fpos;
1130
1131 fpos = vma->vm_pgoff;
1132 fpos <<= PAGE_SHIFT;
1133
1134 old_fs = get_fs();
1135 set_fs(KERNEL_DS);
8feae131 1136 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
1da177e4
LT
1137 set_fs(old_fs);
1138
1139 if (ret < 0)
1140 goto error_free;
1141
1142 /* clear the last little bit */
8feae131
DH
1143 if (ret < rlen)
1144 memset(base + ret, 0, rlen - ret);
1da177e4 1145
1da177e4
LT
1146 }
1147
1148 return 0;
1149
1150error_free:
8feae131
DH
1151 free_page_series(region->vm_start, region->vm_end);
1152 region->vm_start = vma->vm_start = 0;
1153 region->vm_end = vma->vm_end = 0;
dd8632a1 1154 region->vm_top = 0;
1da177e4
LT
1155 return ret;
1156
1157enomem:
05ae6fa3
GU
1158 printk("Allocation of length %lu from process %d (%s) failed\n",
1159 len, current->pid, current->comm);
1da177e4
LT
1160 show_free_areas();
1161 return -ENOMEM;
1162}
1163
1164/*
1165 * handle mapping creation for uClinux
1166 */
1167unsigned long do_mmap_pgoff(struct file *file,
1168 unsigned long addr,
1169 unsigned long len,
1170 unsigned long prot,
1171 unsigned long flags,
1172 unsigned long pgoff)
1173{
8feae131
DH
1174 struct vm_area_struct *vma;
1175 struct vm_region *region;
1da177e4 1176 struct rb_node *rb;
8feae131 1177 unsigned long capabilities, vm_flags, result;
1da177e4
LT
1178 int ret;
1179
8feae131
DH
1180 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1181
1da177e4
LT
1182 /* decide whether we should attempt the mapping, and if so what sort of
1183 * mapping */
1184 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1185 &capabilities);
8feae131
DH
1186 if (ret < 0) {
1187 kleave(" = %d [val]", ret);
1da177e4 1188 return ret;
8feae131 1189 }
1da177e4 1190
06aab5a3
DH
1191 /* we ignore the address hint */
1192 addr = 0;
1193
1da177e4
LT
1194 /* we've determined that we can make the mapping, now translate what we
1195 * now know into VMA flags */
1196 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1197
8feae131
DH
1198 /* we're going to need to record the mapping */
1199 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1200 if (!region)
1201 goto error_getting_region;
1202
1203 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1204 if (!vma)
1205 goto error_getting_vma;
1da177e4 1206
1e2ae599 1207 region->vm_usage = 1;
8feae131
DH
1208 region->vm_flags = vm_flags;
1209 region->vm_pgoff = pgoff;
1210
5beb4930 1211 INIT_LIST_HEAD(&vma->anon_vma_chain);
8feae131
DH
1212 vma->vm_flags = vm_flags;
1213 vma->vm_pgoff = pgoff;
1da177e4 1214
8feae131
DH
1215 if (file) {
1216 region->vm_file = file;
1217 get_file(file);
1218 vma->vm_file = file;
1219 get_file(file);
1220 if (vm_flags & VM_EXECUTABLE) {
1221 added_exe_file_vma(current->mm);
1222 vma->vm_mm = current->mm;
1223 }
1224 }
1225
1226 down_write(&nommu_region_sem);
1227
1228 /* if we want to share, we need to check for regions created by other
1da177e4 1229 * mmap() calls that overlap with our proposed mapping
8feae131 1230 * - we can only share with a superset match on most regular files
1da177e4
LT
1231 * - shared mappings on character devices and memory backed files are
1232 * permitted to overlap inexactly as far as we are concerned for in
1233 * these cases, sharing is handled in the driver or filesystem rather
1234 * than here
1235 */
1236 if (vm_flags & VM_MAYSHARE) {
8feae131
DH
1237 struct vm_region *pregion;
1238 unsigned long pglen, rpglen, pgend, rpgend, start;
1da177e4 1239
8feae131
DH
1240 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1241 pgend = pgoff + pglen;
165b2392 1242
8feae131
DH
1243 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1244 pregion = rb_entry(rb, struct vm_region, vm_rb);
1da177e4 1245
8feae131 1246 if (!(pregion->vm_flags & VM_MAYSHARE))
1da177e4
LT
1247 continue;
1248
1249 /* search for overlapping mappings on the same file */
8feae131
DH
1250 if (pregion->vm_file->f_path.dentry->d_inode !=
1251 file->f_path.dentry->d_inode)
1da177e4
LT
1252 continue;
1253
8feae131 1254 if (pregion->vm_pgoff >= pgend)
1da177e4
LT
1255 continue;
1256
8feae131
DH
1257 rpglen = pregion->vm_end - pregion->vm_start;
1258 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1259 rpgend = pregion->vm_pgoff + rpglen;
1260 if (pgoff >= rpgend)
1da177e4
LT
1261 continue;
1262
8feae131
DH
1263 /* handle inexactly overlapping matches between
1264 * mappings */
1265 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1266 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1267 /* new mapping is not a subset of the region */
1da177e4
LT
1268 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1269 goto sharing_violation;
1270 continue;
1271 }
1272
8feae131 1273 /* we've found a region we can share */
1e2ae599 1274 pregion->vm_usage++;
8feae131
DH
1275 vma->vm_region = pregion;
1276 start = pregion->vm_start;
1277 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1278 vma->vm_start = start;
1279 vma->vm_end = start + len;
1280
1281 if (pregion->vm_flags & VM_MAPPED_COPY) {
1282 kdebug("share copy");
1283 vma->vm_flags |= VM_MAPPED_COPY;
1284 } else {
1285 kdebug("share mmap");
1286 ret = do_mmap_shared_file(vma);
1287 if (ret < 0) {
1288 vma->vm_region = NULL;
1289 vma->vm_start = 0;
1290 vma->vm_end = 0;
1e2ae599 1291 pregion->vm_usage--;
8feae131
DH
1292 pregion = NULL;
1293 goto error_just_free;
1294 }
1295 }
1296 fput(region->vm_file);
1297 kmem_cache_free(vm_region_jar, region);
1298 region = pregion;
1299 result = start;
1300 goto share;
1da177e4
LT
1301 }
1302
1da177e4
LT
1303 /* obtain the address at which to make a shared mapping
1304 * - this is the hook for quasi-memory character devices to
1305 * tell us the location of a shared mapping
1306 */
645d83c5 1307 if (capabilities & BDI_CAP_MAP_DIRECT) {
1da177e4
LT
1308 addr = file->f_op->get_unmapped_area(file, addr, len,
1309 pgoff, flags);
1310 if (IS_ERR((void *) addr)) {
1311 ret = addr;
1312 if (ret != (unsigned long) -ENOSYS)
8feae131 1313 goto error_just_free;
1da177e4
LT
1314
1315 /* the driver refused to tell us where to site
1316 * the mapping so we'll have to attempt to copy
1317 * it */
1318 ret = (unsigned long) -ENODEV;
1319 if (!(capabilities & BDI_CAP_MAP_COPY))
8feae131 1320 goto error_just_free;
1da177e4
LT
1321
1322 capabilities &= ~BDI_CAP_MAP_DIRECT;
8feae131
DH
1323 } else {
1324 vma->vm_start = region->vm_start = addr;
1325 vma->vm_end = region->vm_end = addr + len;
1da177e4
LT
1326 }
1327 }
1328 }
1329
8feae131 1330 vma->vm_region = region;
1da177e4 1331
645d83c5
DH
1332 /* set up the mapping
1333 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1334 */
1da177e4 1335 if (file && vma->vm_flags & VM_SHARED)
8feae131 1336 ret = do_mmap_shared_file(vma);
1da177e4 1337 else
645d83c5 1338 ret = do_mmap_private(vma, region, len, capabilities);
1da177e4 1339 if (ret < 0)
645d83c5
DH
1340 goto error_just_free;
1341 add_nommu_region(region);
8feae131 1342
ea637639
JZ
1343 /* clear anonymous mappings that don't ask for uninitialized data */
1344 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1345 memset((void *)region->vm_start, 0,
1346 region->vm_end - region->vm_start);
1347
1da177e4 1348 /* okay... we have a mapping; now we have to register it */
8feae131 1349 result = vma->vm_start;
1da177e4 1350
1da177e4
LT
1351 current->mm->total_vm += len >> PAGE_SHIFT;
1352
8feae131
DH
1353share:
1354 add_vma_to_mm(current->mm, vma);
1da177e4 1355
cfe79c00
MF
1356 /* we flush the region from the icache only when the first executable
1357 * mapping of it is made */
1358 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1359 flush_icache_range(region->vm_start, region->vm_end);
1360 region->vm_icache_flushed = true;
1361 }
1da177e4 1362
cfe79c00 1363 up_write(&nommu_region_sem);
1da177e4 1364
8feae131
DH
1365 kleave(" = %lx", result);
1366 return result;
1da177e4 1367
8feae131
DH
1368error_just_free:
1369 up_write(&nommu_region_sem);
1370error:
89a86402
DH
1371 if (region->vm_file)
1372 fput(region->vm_file);
8feae131 1373 kmem_cache_free(vm_region_jar, region);
89a86402
DH
1374 if (vma->vm_file)
1375 fput(vma->vm_file);
8feae131
DH
1376 if (vma->vm_flags & VM_EXECUTABLE)
1377 removed_exe_file_vma(vma->vm_mm);
1378 kmem_cache_free(vm_area_cachep, vma);
1379 kleave(" = %d", ret);
1380 return ret;
1381
1382sharing_violation:
1383 up_write(&nommu_region_sem);
1384 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1385 ret = -EINVAL;
1386 goto error;
1da177e4 1387
8feae131
DH
1388error_getting_vma:
1389 kmem_cache_free(vm_region_jar, region);
1390 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1391 " from process %d failed\n",
1da177e4
LT
1392 len, current->pid);
1393 show_free_areas();
1394 return -ENOMEM;
1395
8feae131
DH
1396error_getting_region:
1397 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1398 " from process %d failed\n",
1da177e4
LT
1399 len, current->pid);
1400 show_free_areas();
1401 return -ENOMEM;
1402}
b5073173 1403EXPORT_SYMBOL(do_mmap_pgoff);
1da177e4 1404
66f0dc48
HD
1405SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1406 unsigned long, prot, unsigned long, flags,
1407 unsigned long, fd, unsigned long, pgoff)
1408{
1409 struct file *file = NULL;
1410 unsigned long retval = -EBADF;
1411
1412 if (!(flags & MAP_ANONYMOUS)) {
1413 file = fget(fd);
1414 if (!file)
1415 goto out;
1416 }
1417
1418 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1419
1420 down_write(&current->mm->mmap_sem);
1421 retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1422 up_write(&current->mm->mmap_sem);
1423
1424 if (file)
1425 fput(file);
1426out:
1427 return retval;
1428}
1429
a4679373
CH
1430#ifdef __ARCH_WANT_SYS_OLD_MMAP
1431struct mmap_arg_struct {
1432 unsigned long addr;
1433 unsigned long len;
1434 unsigned long prot;
1435 unsigned long flags;
1436 unsigned long fd;
1437 unsigned long offset;
1438};
1439
1440SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1441{
1442 struct mmap_arg_struct a;
1443
1444 if (copy_from_user(&a, arg, sizeof(a)))
1445 return -EFAULT;
1446 if (a.offset & ~PAGE_MASK)
1447 return -EINVAL;
1448
1449 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1450 a.offset >> PAGE_SHIFT);
1451}
1452#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1453
1da177e4 1454/*
8feae131
DH
1455 * split a vma into two pieces at address 'addr', a new vma is allocated either
1456 * for the first part or the tail.
1da177e4 1457 */
8feae131
DH
1458int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1459 unsigned long addr, int new_below)
1da177e4 1460{
8feae131
DH
1461 struct vm_area_struct *new;
1462 struct vm_region *region;
1463 unsigned long npages;
1da177e4 1464
8feae131 1465 kenter("");
1da177e4 1466
779c1023
DH
1467 /* we're only permitted to split anonymous regions (these should have
1468 * only a single usage on the region) */
1469 if (vma->vm_file)
8feae131 1470 return -ENOMEM;
1da177e4 1471
8feae131
DH
1472 if (mm->map_count >= sysctl_max_map_count)
1473 return -ENOMEM;
1da177e4 1474
8feae131
DH
1475 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1476 if (!region)
1477 return -ENOMEM;
1da177e4 1478
8feae131
DH
1479 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1480 if (!new) {
1481 kmem_cache_free(vm_region_jar, region);
1482 return -ENOMEM;
1483 }
1484
1485 /* most fields are the same, copy all, and then fixup */
1486 *new = *vma;
1487 *region = *vma->vm_region;
1488 new->vm_region = region;
1489
1490 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1491
1492 if (new_below) {
dd8632a1 1493 region->vm_top = region->vm_end = new->vm_end = addr;
8feae131
DH
1494 } else {
1495 region->vm_start = new->vm_start = addr;
1496 region->vm_pgoff = new->vm_pgoff += npages;
1da177e4 1497 }
8feae131
DH
1498
1499 if (new->vm_ops && new->vm_ops->open)
1500 new->vm_ops->open(new);
1501
1502 delete_vma_from_mm(vma);
1503 down_write(&nommu_region_sem);
1504 delete_nommu_region(vma->vm_region);
1505 if (new_below) {
1506 vma->vm_region->vm_start = vma->vm_start = addr;
1507 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1508 } else {
1509 vma->vm_region->vm_end = vma->vm_end = addr;
dd8632a1 1510 vma->vm_region->vm_top = addr;
8feae131
DH
1511 }
1512 add_nommu_region(vma->vm_region);
1513 add_nommu_region(new->vm_region);
1514 up_write(&nommu_region_sem);
1515 add_vma_to_mm(mm, vma);
1516 add_vma_to_mm(mm, new);
1517 return 0;
1da177e4
LT
1518}
1519
3034097a 1520/*
8feae131
DH
1521 * shrink a VMA by removing the specified chunk from either the beginning or
1522 * the end
3034097a 1523 */
8feae131
DH
1524static int shrink_vma(struct mm_struct *mm,
1525 struct vm_area_struct *vma,
1526 unsigned long from, unsigned long to)
1da177e4 1527{
8feae131 1528 struct vm_region *region;
1da177e4 1529
8feae131 1530 kenter("");
1da177e4 1531
8feae131
DH
1532 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1533 * and list */
1534 delete_vma_from_mm(vma);
1535 if (from > vma->vm_start)
1536 vma->vm_end = from;
1537 else
1538 vma->vm_start = to;
1539 add_vma_to_mm(mm, vma);
1da177e4 1540
8feae131
DH
1541 /* cut the backing region down to size */
1542 region = vma->vm_region;
1e2ae599 1543 BUG_ON(region->vm_usage != 1);
8feae131
DH
1544
1545 down_write(&nommu_region_sem);
1546 delete_nommu_region(region);
dd8632a1
PM
1547 if (from > region->vm_start) {
1548 to = region->vm_top;
1549 region->vm_top = region->vm_end = from;
1550 } else {
8feae131 1551 region->vm_start = to;
dd8632a1 1552 }
8feae131
DH
1553 add_nommu_region(region);
1554 up_write(&nommu_region_sem);
1555
1556 free_page_series(from, to);
1557 return 0;
1558}
1da177e4 1559
8feae131
DH
1560/*
1561 * release a mapping
1562 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1563 * VMA, though it need not cover the whole VMA
1564 */
1565int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1566{
1567 struct vm_area_struct *vma;
1568 struct rb_node *rb;
1569 unsigned long end = start + len;
1570 int ret;
1da177e4 1571
8feae131 1572 kenter(",%lx,%zx", start, len);
1da177e4 1573
8feae131
DH
1574 if (len == 0)
1575 return -EINVAL;
365e9c87 1576
8feae131
DH
1577 /* find the first potentially overlapping VMA */
1578 vma = find_vma(mm, start);
1579 if (!vma) {
33e5d769
DH
1580 static int limit = 0;
1581 if (limit < 5) {
1582 printk(KERN_WARNING
1583 "munmap of memory not mmapped by process %d"
1584 " (%s): 0x%lx-0x%lx\n",
1585 current->pid, current->comm,
1586 start, start + len - 1);
1587 limit++;
1588 }
8feae131
DH
1589 return -EINVAL;
1590 }
1da177e4 1591
8feae131
DH
1592 /* we're allowed to split an anonymous VMA but not a file-backed one */
1593 if (vma->vm_file) {
1594 do {
1595 if (start > vma->vm_start) {
1596 kleave(" = -EINVAL [miss]");
1597 return -EINVAL;
1598 }
1599 if (end == vma->vm_end)
1600 goto erase_whole_vma;
1601 rb = rb_next(&vma->vm_rb);
1602 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1603 } while (rb);
1604 kleave(" = -EINVAL [split file]");
1605 return -EINVAL;
1606 } else {
1607 /* the chunk must be a subset of the VMA found */
1608 if (start == vma->vm_start && end == vma->vm_end)
1609 goto erase_whole_vma;
1610 if (start < vma->vm_start || end > vma->vm_end) {
1611 kleave(" = -EINVAL [superset]");
1612 return -EINVAL;
1613 }
1614 if (start & ~PAGE_MASK) {
1615 kleave(" = -EINVAL [unaligned start]");
1616 return -EINVAL;
1617 }
1618 if (end != vma->vm_end && end & ~PAGE_MASK) {
1619 kleave(" = -EINVAL [unaligned split]");
1620 return -EINVAL;
1621 }
1622 if (start != vma->vm_start && end != vma->vm_end) {
1623 ret = split_vma(mm, vma, start, 1);
1624 if (ret < 0) {
1625 kleave(" = %d [split]", ret);
1626 return ret;
1627 }
1628 }
1629 return shrink_vma(mm, vma, start, end);
1630 }
1da177e4 1631
8feae131
DH
1632erase_whole_vma:
1633 delete_vma_from_mm(vma);
1634 delete_vma(mm, vma);
1635 kleave(" = 0");
1da177e4
LT
1636 return 0;
1637}
b5073173 1638EXPORT_SYMBOL(do_munmap);
1da177e4 1639
6a6160a7 1640SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
3034097a
DH
1641{
1642 int ret;
1643 struct mm_struct *mm = current->mm;
1644
1645 down_write(&mm->mmap_sem);
1646 ret = do_munmap(mm, addr, len);
1647 up_write(&mm->mmap_sem);
1648 return ret;
1649}
1650
1651/*
8feae131 1652 * release all the mappings made in a process's VM space
3034097a 1653 */
8feae131 1654void exit_mmap(struct mm_struct *mm)
1da177e4 1655{
8feae131 1656 struct vm_area_struct *vma;
1da177e4 1657
8feae131
DH
1658 if (!mm)
1659 return;
1da177e4 1660
8feae131 1661 kenter("");
1da177e4 1662
8feae131 1663 mm->total_vm = 0;
1da177e4 1664
8feae131
DH
1665 while ((vma = mm->mmap)) {
1666 mm->mmap = vma->vm_next;
1667 delete_vma_from_mm(vma);
1668 delete_vma(mm, vma);
1da177e4 1669 }
8feae131
DH
1670
1671 kleave("");
1da177e4
LT
1672}
1673
1da177e4
LT
1674unsigned long do_brk(unsigned long addr, unsigned long len)
1675{
1676 return -ENOMEM;
1677}
1678
1679/*
6fa5f80b
DH
1680 * expand (or shrink) an existing mapping, potentially moving it at the same
1681 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1da177e4 1682 *
6fa5f80b 1683 * under NOMMU conditions, we only permit changing a mapping's size, and only
8feae131
DH
1684 * as long as it stays within the region allocated by do_mmap_private() and the
1685 * block is not shareable
1da177e4 1686 *
6fa5f80b 1687 * MREMAP_FIXED is not supported under NOMMU conditions
1da177e4
LT
1688 */
1689unsigned long do_mremap(unsigned long addr,
1690 unsigned long old_len, unsigned long new_len,
1691 unsigned long flags, unsigned long new_addr)
1692{
6fa5f80b 1693 struct vm_area_struct *vma;
1da177e4
LT
1694
1695 /* insanity checks first */
8feae131 1696 if (old_len == 0 || new_len == 0)
1da177e4
LT
1697 return (unsigned long) -EINVAL;
1698
8feae131
DH
1699 if (addr & ~PAGE_MASK)
1700 return -EINVAL;
1701
1da177e4
LT
1702 if (flags & MREMAP_FIXED && new_addr != addr)
1703 return (unsigned long) -EINVAL;
1704
8feae131 1705 vma = find_vma_exact(current->mm, addr, old_len);
6fa5f80b
DH
1706 if (!vma)
1707 return (unsigned long) -EINVAL;
1da177e4 1708
6fa5f80b 1709 if (vma->vm_end != vma->vm_start + old_len)
1da177e4
LT
1710 return (unsigned long) -EFAULT;
1711
6fa5f80b 1712 if (vma->vm_flags & VM_MAYSHARE)
1da177e4
LT
1713 return (unsigned long) -EPERM;
1714
8feae131 1715 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1da177e4
LT
1716 return (unsigned long) -ENOMEM;
1717
1718 /* all checks complete - do it */
6fa5f80b 1719 vma->vm_end = vma->vm_start + new_len;
6fa5f80b
DH
1720 return vma->vm_start;
1721}
b5073173 1722EXPORT_SYMBOL(do_mremap);
6fa5f80b 1723
6a6160a7
HC
1724SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1725 unsigned long, new_len, unsigned long, flags,
1726 unsigned long, new_addr)
6fa5f80b
DH
1727{
1728 unsigned long ret;
1729
1730 down_write(&current->mm->mmap_sem);
1731 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1732 up_write(&current->mm->mmap_sem);
1733 return ret;
1da177e4
LT
1734}
1735
6aab341e 1736struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
deceb6cd 1737 unsigned int foll_flags)
1da177e4
LT
1738{
1739 return NULL;
1740}
1741
1da177e4
LT
1742int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1743 unsigned long to, unsigned long size, pgprot_t prot)
1744{
66aa2b4b
GU
1745 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1746 return 0;
1da177e4 1747}
22c4af40 1748EXPORT_SYMBOL(remap_pfn_range);
1da177e4 1749
f905bc44
PM
1750int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1751 unsigned long pgoff)
1752{
1753 unsigned int size = vma->vm_end - vma->vm_start;
1754
1755 if (!(vma->vm_flags & VM_USERMAP))
1756 return -EINVAL;
1757
1758 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1759 vma->vm_end = vma->vm_start + size;
1760
1761 return 0;
1762}
1763EXPORT_SYMBOL(remap_vmalloc_range);
1764
1da177e4
LT
1765void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1766{
1767}
1768
1769unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1770 unsigned long len, unsigned long pgoff, unsigned long flags)
1771{
1772 return -ENOMEM;
1773}
1774
1363c3cd 1775void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1da177e4
LT
1776{
1777}
1778
1da177e4
LT
1779void unmap_mapping_range(struct address_space *mapping,
1780 loff_t const holebegin, loff_t const holelen,
1781 int even_cows)
1782{
1783}
22c4af40 1784EXPORT_SYMBOL(unmap_mapping_range);
1da177e4
LT
1785
1786/*
1787 * Check that a process has enough memory to allocate a new virtual
1788 * mapping. 0 means there is enough memory for the allocation to
1789 * succeed and -ENOMEM implies there is not.
1790 *
1791 * We currently support three overcommit policies, which are set via the
1792 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1793 *
1794 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1795 * Additional code 2002 Jul 20 by Robert Love.
1796 *
1797 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1798 *
1799 * Note this is a helper function intended to be used by LSMs which
1800 * wish to use this logic.
1801 */
34b4e4aa 1802int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1da177e4
LT
1803{
1804 unsigned long free, allowed;
1805
1806 vm_acct_memory(pages);
1807
1808 /*
1809 * Sometimes we want to use more memory than we have
1810 */
1811 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1812 return 0;
1813
1814 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1815 unsigned long n;
1816
347ce434 1817 free = global_page_state(NR_FILE_PAGES);
1da177e4
LT
1818 free += nr_swap_pages;
1819
1820 /*
1821 * Any slabs which are created with the
1822 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1823 * which are reclaimable, under pressure. The dentry
1824 * cache and most inode caches should fall into this
1825 */
972d1a7b 1826 free += global_page_state(NR_SLAB_RECLAIMABLE);
1da177e4
LT
1827
1828 /*
1829 * Leave the last 3% for root
1830 */
1831 if (!cap_sys_admin)
1832 free -= free / 32;
1833
1834 if (free > pages)
1835 return 0;
1836
1837 /*
1838 * nr_free_pages() is very expensive on large systems,
1839 * only call if we're about to fail.
1840 */
1841 n = nr_free_pages();
d5ddc79b
HA
1842
1843 /*
1844 * Leave reserved pages. The pages are not for anonymous pages.
1845 */
1846 if (n <= totalreserve_pages)
1847 goto error;
1848 else
1849 n -= totalreserve_pages;
1850
1851 /*
1852 * Leave the last 3% for root
1853 */
1da177e4
LT
1854 if (!cap_sys_admin)
1855 n -= n / 32;
1856 free += n;
1857
1858 if (free > pages)
1859 return 0;
d5ddc79b
HA
1860
1861 goto error;
1da177e4
LT
1862 }
1863
1864 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1865 /*
1866 * Leave the last 3% for root
1867 */
1868 if (!cap_sys_admin)
1869 allowed -= allowed / 32;
1870 allowed += total_swap_pages;
1871
1872 /* Don't let a single process grow too big:
1873 leave 3% of the size of this process for other processes */
731572d3
AC
1874 if (mm)
1875 allowed -= mm->total_vm / 32;
1da177e4 1876
00a62ce9 1877 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1da177e4 1878 return 0;
00a62ce9 1879
d5ddc79b 1880error:
1da177e4
LT
1881 vm_unacct_memory(pages);
1882
1883 return -ENOMEM;
1884}
1885
1886int in_gate_area_no_task(unsigned long addr)
1887{
1888 return 0;
1889}
b0e15190 1890
d0217ac0 1891int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
b0e15190
DH
1892{
1893 BUG();
d0217ac0 1894 return 0;
b0e15190 1895}
b5073173 1896EXPORT_SYMBOL(filemap_fault);
0ec76a11
DH
1897
1898/*
1899 * Access another process' address space.
1900 * - source/target buffer must be kernel space
1901 */
1902int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1903{
0ec76a11
DH
1904 struct vm_area_struct *vma;
1905 struct mm_struct *mm;
1906
1907 if (addr + len < addr)
1908 return 0;
1909
1910 mm = get_task_mm(tsk);
1911 if (!mm)
1912 return 0;
1913
1914 down_read(&mm->mmap_sem);
1915
1916 /* the access must start within one of the target process's mappings */
0159b141
DH
1917 vma = find_vma(mm, addr);
1918 if (vma) {
0ec76a11
DH
1919 /* don't overrun this mapping */
1920 if (addr + len >= vma->vm_end)
1921 len = vma->vm_end - addr;
1922
1923 /* only read or write mappings where it is permitted */
d00c7b99 1924 if (write && vma->vm_flags & VM_MAYWRITE)
7959722b
JZ
1925 copy_to_user_page(vma, NULL, addr,
1926 (void *) addr, buf, len);
d00c7b99 1927 else if (!write && vma->vm_flags & VM_MAYREAD)
7959722b
JZ
1928 copy_from_user_page(vma, NULL, addr,
1929 buf, (void *) addr, len);
0ec76a11
DH
1930 else
1931 len = 0;
1932 } else {
1933 len = 0;
1934 }
1935
1936 up_read(&mm->mmap_sem);
1937 mmput(mm);
1938 return len;
1939}
7e660872
DH
1940
1941/**
1942 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
1943 * @inode: The inode to check
1944 * @size: The current filesize of the inode
1945 * @newsize: The proposed filesize of the inode
1946 *
1947 * Check the shared mappings on an inode on behalf of a shrinking truncate to
1948 * make sure that that any outstanding VMAs aren't broken and then shrink the
1949 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
1950 * automatically grant mappings that are too large.
1951 */
1952int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
1953 size_t newsize)
1954{
1955 struct vm_area_struct *vma;
1956 struct prio_tree_iter iter;
1957 struct vm_region *region;
1958 pgoff_t low, high;
1959 size_t r_size, r_top;
1960
1961 low = newsize >> PAGE_SHIFT;
1962 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1963
1964 down_write(&nommu_region_sem);
1965
1966 /* search for VMAs that fall within the dead zone */
1967 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
1968 low, high) {
1969 /* found one - only interested if it's shared out of the page
1970 * cache */
1971 if (vma->vm_flags & VM_SHARED) {
1972 up_write(&nommu_region_sem);
1973 return -ETXTBSY; /* not quite true, but near enough */
1974 }
1975 }
1976
1977 /* reduce any regions that overlap the dead zone - if in existence,
1978 * these will be pointed to by VMAs that don't overlap the dead zone
1979 *
1980 * we don't check for any regions that start beyond the EOF as there
1981 * shouldn't be any
1982 */
1983 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
1984 0, ULONG_MAX) {
1985 if (!(vma->vm_flags & VM_SHARED))
1986 continue;
1987
1988 region = vma->vm_region;
1989 r_size = region->vm_top - region->vm_start;
1990 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
1991
1992 if (r_top > newsize) {
1993 region->vm_top -= r_top - newsize;
1994 if (region->vm_end > region->vm_top)
1995 region->vm_end = region->vm_top;
1996 }
1997 }
1998
1999 up_write(&nommu_region_sem);
2000 return 0;
2001}