blob: 4358032566e950f25812fef04fa951dcc39f6795 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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 *
David Howells8feae132009-01-08 12:04:47 +00009 * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -070010 * 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>
Paul Mundt29c185e2010-12-24 12:08:30 +090013 * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 */
15
David Howellsf2b85442007-10-29 13:15:39 +000016#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#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>
Al Viro120a7952010-10-30 02:54:44 -040031#include <linux/audit.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032
33#include <asm/uaccess.h>
34#include <asm/tlb.h>
35#include <asm/tlbflush.h>
Bernd Schmidteb8cdec2009-09-21 17:03:57 -070036#include <asm/mmu_context.h>
David Howells8feae132009-01-08 12:04:47 +000037#include "internal.h"
38
David Howells8feae132009-01-08 12:04:47 +000039#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
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
55void *high_memory;
56struct page *mem_map;
57unsigned long max_mapnr;
58unsigned long num_physpages;
Hugh Dickins4266c972009-09-23 17:05:53 +010059unsigned long highest_memmap_pfn;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -070060struct percpu_counter vm_committed_as;
Linus Torvalds1da177e2005-04-16 15:20:36 -070061int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
62int sysctl_overcommit_ratio = 50; /* default is 50% */
63int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
David Howellsfc4d5c22009-05-06 16:03:05 -070064int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
Linus Torvalds1da177e2005-04-16 15:20:36 -070065int heap_stack_gap = 0;
66
David Howells33e5d7692009-04-02 16:56:32 -070067atomic_long_t mmap_pages_allocated;
David Howells8feae132009-01-08 12:04:47 +000068
Linus Torvalds1da177e2005-04-16 15:20:36 -070069EXPORT_SYMBOL(mem_map);
Wu, Bryan6a04de62007-04-11 23:28:47 -070070EXPORT_SYMBOL(num_physpages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070071
David Howells8feae132009-01-08 12:04:47 +000072/* 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +040077const struct vm_operations_struct generic_file_vm_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070078};
79
80/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070081 * 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
Michael Hennerich4016a132008-04-28 02:13:38 -070090 /*
91 * If the object we have should not have ksize performed on it,
92 * return size of 0
93 */
Paul Mundt5a1603b2008-06-12 16:29:55 +090094 if (!objp || !virt_addr_valid(objp))
Paul Mundt6cfd53f2008-06-05 22:46:08 -070095 return 0;
96
97 page = virt_to_head_page(objp);
Paul Mundt6cfd53f2008-06-05 22:46:08 -070098
99 /*
100 * If the allocator sets PageSlab, we know the pointer came from
101 * kmalloc().
102 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103 if (PageSlab(page))
104 return ksize(objp);
105
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700106 /*
Paul Mundtab2e83e2009-01-08 12:04:48 +0000107 * 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 /*
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700121 * The ksize() function is only guaranteed to work for pointers
Paul Mundt5a1603b2008-06-12 16:29:55 +0900122 * returned by kmalloc(). So handle arbitrary pointers here.
Paul Mundt6cfd53f2008-06-05 22:46:08 -0700123 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900124 return PAGE_SIZE << compound_order(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125}
126
Nick Pigginb291f002008-10-18 20:26:44 -0700127int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Hugh Dickins4266c972009-09-23 17:05:53 +0100128 unsigned long start, int nr_pages, unsigned int foll_flags,
Michel Lespinasse53a77062011-01-13 15:46:14 -0800129 struct page **pages, struct vm_area_struct **vmas,
130 int *retry)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700132 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700133 unsigned long vm_flags;
134 int i;
135
136 /* calculate required read or write permissions.
Hugh Dickins58fa8792009-09-21 17:03:31 -0700137 * If FOLL_FORCE is set, we only require the "MAY" flags.
David Howells7b4d5b82006-09-27 01:50:18 -0700138 */
Hugh Dickins58fa8792009-09-21 17:03:31 -0700139 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143
Peter Zijlstra9d737772009-06-25 11:58:55 +0200144 for (i = 0; i < nr_pages; i++) {
David Howells7561e8c2010-03-25 16:48:38 +0000145 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700146 if (!vma)
147 goto finish_or_fault;
148
149 /* protect what we can, including chardevs */
Hugh Dickins1c3aff12009-09-21 17:03:24 -0700150 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
151 !(vm_flags & vma->vm_flags))
David Howells7b4d5b82006-09-27 01:50:18 -0700152 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700153
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 if (pages) {
155 pages[i] = virt_to_page(start);
156 if (pages[i])
157 page_cache_get(pages[i]);
158 }
159 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700160 vmas[i] = vma;
David Howellse1ee65d2010-03-25 16:48:44 +0000161 start = (start + PAGE_SIZE) & PAGE_MASK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162 }
David Howells7b4d5b82006-09-27 01:50:18 -0700163
164 return i;
165
166finish_or_fault:
167 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168}
Nick Pigginb291f002008-10-18 20:26:44 -0700169
Nick Pigginb291f002008-10-18 20:26:44 -0700170/*
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,
Peter Zijlstra9d737772009-06-25 11:58:55 +0200178 unsigned long start, int nr_pages, int write, int force,
Nick Pigginb291f002008-10-18 20:26:44 -0700179 struct page **pages, struct vm_area_struct **vmas)
180{
181 int flags = 0;
182
183 if (write)
Hugh Dickins58fa8792009-09-21 17:03:31 -0700184 flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -0700185 if (force)
Hugh Dickins58fa8792009-09-21 17:03:31 -0700186 flags |= FOLL_FORCE;
Nick Pigginb291f002008-10-18 20:26:44 -0700187
Michel Lespinasse53a77062011-01-13 15:46:14 -0800188 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
189 NULL);
Nick Pigginb291f002008-10-18 20:26:44 -0700190}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000191EXPORT_SYMBOL(get_user_pages);
192
Paul Mundtdfc2f912009-06-26 04:31:57 +0900193/**
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214DEFINE_RWLOCK(vmlist_lock);
215struct vm_struct *vmlist;
216
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800217void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218{
219 kfree(addr);
220}
Paul Mundtb5073172007-07-21 04:37:25 -0700221EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222
Al Virodd0fc662005-10-07 07:46:04 +0100223void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224{
225 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200226 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
227 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 */
Nick Piggin84097512006-03-22 00:08:34 -0800229 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
Paul Mundtb5073172007-07-21 04:37:25 -0700231EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
Paul Mundtf905bc42008-02-04 22:29:59 -0800233void *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(&current->mm->mmap_sem);
243 vma = find_vma(current->mm, (unsigned long)ret);
244 if (vma)
245 vma->vm_flags |= VM_USERMAP;
246 up_write(&current->mm->mmap_sem);
247 }
248
249 return ret;
250}
251EXPORT_SYMBOL(vmalloc_user);
252
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800253struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254{
255 return virt_to_page(addr);
256}
Paul Mundtb5073172007-07-21 04:37:25 -0700257EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800259unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260{
261 return page_to_pfn(virt_to_page(addr));
262}
Paul Mundtb5073172007-07-21 04:37:25 -0700263EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264
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 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200289 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 * use __vmalloc() instead.
291 */
292void *vmalloc(unsigned long size)
293{
294 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
295}
Andrew Mortonf6138882006-02-28 16:59:18 -0800296EXPORT_SYMBOL(vmalloc);
297
Dave Younge1ca7782010-10-26 14:22:06 -0700298/*
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 */
Andrew Mortonf6138882006-02-28 16:59:18 -0800328void *vmalloc_node(unsigned long size, int node)
329{
330 return vmalloc(size);
331}
Paul Mundt9a14f652010-12-24 11:50:34 +0900332EXPORT_SYMBOL(vmalloc_node);
Dave Younge1ca7782010-10-26 14:22:06 -0700333
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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351
Paul Mundt1af446e2008-08-04 16:01:47 +0900352#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
Paul Mundtb5073172007-07-21 04:37:25 -0700373/**
374 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 * @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}
Paul Mundtb5073172007-07-21 04:37:25 -0700384EXPORT_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.
Paul Mundtf905bc42008-02-04 22:29:59 -0800392 *
393 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
394 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700395 */
396void *vmalloc_32_user(unsigned long size)
397{
Paul Mundtf905bc42008-02-04 22:29:59 -0800398 /*
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);
Paul Mundtb5073172007-07-21 04:37:25 -0700403}
404EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405
406void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
407{
408 BUG();
409 return NULL;
410}
Paul Mundtb5073172007-07-21 04:37:25 -0700411EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800413void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414{
415 BUG();
416}
Paul Mundtb5073172007-07-21 04:37:25 -0700417EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418
Paul Mundteb6434d2009-01-21 17:45:47 +0900419void *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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700438 * 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
Paul Mundt29c185e2010-12-24 12:08:30 +0900445/**
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)
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
Paul Mundtb5073172007-07-21 04:37:25 -0700470int 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
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700477/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 * 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 */
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100484SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485{
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 */
Mike Frysingercfe79c02010-01-06 17:23:23 +0000505 flush_icache_range(mm->brk, brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 return mm->brk = brk;
507}
508
David Howells8feae132009-01-08 12:04:47 +0000509/*
510 * initialise the VMA and region record slabs
511 */
512void __init mmap_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700514 int ret;
515
516 ret = percpu_counter_init(&vm_committed_as, 0);
517 VM_BUG_ON(ret);
David Howells33e5d7692009-04-02 16:56:32 -0700518 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
David Howells8feae132009-01-08 12:04:47 +0000519}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
David Howells8feae132009-01-08 12:04:47 +0000521/*
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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530
David Howells8feae132009-01-08 12:04:47 +0000531 lastp = rb_first(&nommu_region_tree);
532 if (!lastp)
533 return;
534
535 last = rb_entry(lastp, struct vm_region, vm_rb);
David Howells33e5d7692009-04-02 16:56:32 -0700536 BUG_ON(unlikely(last->vm_end <= last->vm_start));
537 BUG_ON(unlikely(last->vm_top < last->vm_end));
David Howells8feae132009-01-08 12:04:47 +0000538
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
David Howells33e5d7692009-04-02 16:56:32 -0700543 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));
David Howells8feae132009-01-08 12:04:47 +0000546
547 lastp = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 }
549}
David Howells8feae132009-01-08 12:04:47 +0000550#else
David Howells33e5d7692009-04-02 16:56:32 -0700551static void validate_nommu_regions(void)
552{
553}
David Howells8feae132009-01-08 12:04:47 +0000554#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
David Howells8feae132009-01-08 12:04:47 +0000566 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(&region->vm_rb, parent, p);
582 rb_insert_color(&region->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(&region->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);
David Howells33e5d7692009-04-02 16:56:32 -0700608 atomic_long_dec(&mmap_pages_allocated);
David Howells8feae132009-01-08 12:04:47 +0000609 if (page_count(page) != 1)
David Howells33e5d7692009-04-02 16:56:32 -0700610 kdebug("free page %p: refcount not one: %d",
611 page, page_count(page));
David Howells8feae132009-01-08 12:04:47 +0000612 put_page(page);
613 }
614}
615
616/*
617 * release a reference to a region
David Howells33e5d7692009-04-02 16:56:32 -0700618 * - the caller must hold the region semaphore for writing, which this releases
Paul Mundtdd8632a2009-01-08 12:04:47 +0000619 * - the region may not have been added to the tree yet, in which case vm_top
David Howells8feae132009-01-08 12:04:47 +0000620 * will equal vm_start
621 */
622static void __put_nommu_region(struct vm_region *region)
623 __releases(nommu_region_sem)
624{
David Howells1e2ae592010-01-15 17:01:33 -0800625 kenter("%p{%d}", region, region->vm_usage);
David Howells8feae132009-01-08 12:04:47 +0000626
627 BUG_ON(!nommu_region_tree.rb_node);
628
David Howells1e2ae592010-01-15 17:01:33 -0800629 if (--region->vm_usage == 0) {
Paul Mundtdd8632a2009-01-08 12:04:47 +0000630 if (region->vm_top > region->vm_start)
David Howells8feae132009-01-08 12:04:47 +0000631 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");
Paul Mundtdd8632a2009-01-08 12:04:47 +0000641 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +0000642 }
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}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657
David Howells30340972006-09-27 01:50:20 -0700658/*
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700659 * 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/*
David Howells30340972006-09-27 01:50:20 -0700675 * add a VMA into a process's mm_struct in the appropriate place in the list
David Howells8feae132009-01-08 12:04:47 +0000676 * and tree and add to the address space's page tree also if not an anonymous
677 * page
David Howells30340972006-09-27 01:50:20 -0700678 * - should be called with mm->mmap_sem held writelocked
679 */
David Howells8feae132009-01-08 12:04:47 +0000680static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
David Howells30340972006-09-27 01:50:20 -0700681{
Namhyung Kim6038def2011-05-24 17:11:22 -0700682 struct vm_area_struct *pvma, *prev;
David Howells8feae132009-01-08 12:04:47 +0000683 struct address_space *mapping;
Namhyung Kim6038def2011-05-24 17:11:22 -0700684 struct rb_node **p, *parent, *rb_prev;
David Howells30340972006-09-27 01:50:20 -0700685
David Howells8feae132009-01-08 12:04:47 +0000686 kenter(",%p", vma);
687
688 BUG_ON(!vma->vm_region);
689
690 mm->map_count++;
691 vma->vm_mm = mm;
692
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700693 protect_vma(vma, vma->vm_flags);
694
David Howells8feae132009-01-08 12:04:47 +0000695 /* add the VMA to the mapping */
696 if (vma->vm_file) {
697 mapping = vma->vm_file->f_mapping;
698
699 flush_dcache_mmap_lock(mapping);
700 vma_prio_tree_insert(vma, &mapping->i_mmap);
701 flush_dcache_mmap_unlock(mapping);
702 }
703
704 /* add the VMA to the tree */
Namhyung Kim6038def2011-05-24 17:11:22 -0700705 parent = rb_prev = NULL;
David Howells8feae132009-01-08 12:04:47 +0000706 p = &mm->mm_rb.rb_node;
707 while (*p) {
708 parent = *p;
709 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
710
711 /* sort by: start addr, end addr, VMA struct addr in that order
712 * (the latter is necessary as we may get identical VMAs) */
713 if (vma->vm_start < pvma->vm_start)
714 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700715 else if (vma->vm_start > pvma->vm_start) {
716 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000717 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700718 } else if (vma->vm_end < pvma->vm_end)
David Howells8feae132009-01-08 12:04:47 +0000719 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700720 else if (vma->vm_end > pvma->vm_end) {
721 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000722 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700723 } else if (vma < pvma)
David Howells8feae132009-01-08 12:04:47 +0000724 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700725 else if (vma > pvma) {
726 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000727 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700728 } else
David Howells8feae132009-01-08 12:04:47 +0000729 BUG();
730 }
731
732 rb_link_node(&vma->vm_rb, parent, p);
733 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
734
735 /* add VMA to the VMA list also */
Namhyung Kim6038def2011-05-24 17:11:22 -0700736 prev = NULL;
737 if (rb_prev)
738 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
David Howells30340972006-09-27 01:50:20 -0700739
Namhyung Kim6038def2011-05-24 17:11:22 -0700740 __vma_link_list(mm, vma, prev, parent);
David Howells8feae132009-01-08 12:04:47 +0000741}
742
743/*
744 * delete a VMA from its owning mm_struct and address space
745 */
746static void delete_vma_from_mm(struct vm_area_struct *vma)
747{
David Howells8feae132009-01-08 12:04:47 +0000748 struct address_space *mapping;
749 struct mm_struct *mm = vma->vm_mm;
750
751 kenter("%p", vma);
752
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700753 protect_vma(vma, 0);
754
David Howells8feae132009-01-08 12:04:47 +0000755 mm->map_count--;
756 if (mm->mmap_cache == vma)
757 mm->mmap_cache = NULL;
758
759 /* remove the VMA from the mapping */
760 if (vma->vm_file) {
761 mapping = vma->vm_file->f_mapping;
762
763 flush_dcache_mmap_lock(mapping);
764 vma_prio_tree_remove(vma, &mapping->i_mmap);
765 flush_dcache_mmap_unlock(mapping);
766 }
767
768 /* remove from the MM's tree and list */
769 rb_erase(&vma->vm_rb, &mm->mm_rb);
Namhyung Kimb951bf22011-05-24 17:11:23 -0700770
771 if (vma->vm_prev)
772 vma->vm_prev->vm_next = vma->vm_next;
773 else
774 mm->mmap = vma->vm_next;
775
776 if (vma->vm_next)
777 vma->vm_next->vm_prev = vma->vm_prev;
David Howells8feae132009-01-08 12:04:47 +0000778
779 vma->vm_mm = NULL;
780}
781
782/*
783 * destroy a VMA record
784 */
785static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
786{
787 kenter("%p", vma);
788 if (vma->vm_ops && vma->vm_ops->close)
789 vma->vm_ops->close(vma);
790 if (vma->vm_file) {
791 fput(vma->vm_file);
792 if (vma->vm_flags & VM_EXECUTABLE)
793 removed_exe_file_vma(mm);
794 }
795 put_nommu_region(vma->vm_region);
796 kmem_cache_free(vm_area_cachep, vma);
David Howells30340972006-09-27 01:50:20 -0700797}
798
799/*
800 * look up the first VMA in which addr resides, NULL if none
801 * - should be called with mm->mmap_sem at least held readlocked
802 */
803struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
804{
David Howells8feae132009-01-08 12:04:47 +0000805 struct vm_area_struct *vma;
David Howells30340972006-09-27 01:50:20 -0700806
David Howells8feae132009-01-08 12:04:47 +0000807 /* check the cache first */
808 vma = mm->mmap_cache;
809 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
810 return vma;
811
Namhyung Kime922c4c2011-05-24 17:11:24 -0700812 /* trawl the list (there may be multiple mappings in which addr
David Howells8feae132009-01-08 12:04:47 +0000813 * resides) */
Namhyung Kime922c4c2011-05-24 17:11:24 -0700814 for (vma = mm->mmap; vma; vma = vma->vm_next) {
David Howells8feae132009-01-08 12:04:47 +0000815 if (vma->vm_start > addr)
816 return NULL;
817 if (vma->vm_end > addr) {
818 mm->mmap_cache = vma;
819 return vma;
820 }
David Howells30340972006-09-27 01:50:20 -0700821 }
822
David Howells30340972006-09-27 01:50:20 -0700823 return NULL;
824}
825EXPORT_SYMBOL(find_vma);
826
827/*
David Howells930e6522006-09-27 01:50:22 -0700828 * find a VMA
829 * - we don't extend stack VMAs under NOMMU conditions
830 */
831struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
832{
David Howells7561e8c2010-03-25 16:48:38 +0000833 return find_vma(mm, addr);
David Howells930e6522006-09-27 01:50:22 -0700834}
835
David Howells8feae132009-01-08 12:04:47 +0000836/*
837 * expand a stack to a given address
838 * - not supported under NOMMU conditions
839 */
Greg Ungerer57c8f632007-07-15 23:38:28 -0700840int expand_stack(struct vm_area_struct *vma, unsigned long address)
841{
842 return -ENOMEM;
843}
844
David Howells930e6522006-09-27 01:50:22 -0700845/*
David Howells6fa5f802006-09-27 01:50:21 -0700846 * look up the first VMA exactly that exactly matches addr
847 * - should be called with mm->mmap_sem at least held readlocked
848 */
David Howells8feae132009-01-08 12:04:47 +0000849static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
850 unsigned long addr,
851 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852{
853 struct vm_area_struct *vma;
David Howells8feae132009-01-08 12:04:47 +0000854 unsigned long end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700855
David Howells8feae132009-01-08 12:04:47 +0000856 /* check the cache first */
857 vma = mm->mmap_cache;
858 if (vma && vma->vm_start == addr && vma->vm_end == end)
859 return vma;
860
Namhyung Kime922c4c2011-05-24 17:11:24 -0700861 /* trawl the list (there may be multiple mappings in which addr
David Howells8feae132009-01-08 12:04:47 +0000862 * resides) */
Namhyung Kime922c4c2011-05-24 17:11:24 -0700863 for (vma = mm->mmap; vma; vma = vma->vm_next) {
David Howells8feae132009-01-08 12:04:47 +0000864 if (vma->vm_start < addr)
865 continue;
866 if (vma->vm_start > addr)
867 return NULL;
868 if (vma->vm_end == end) {
869 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 return vma;
David Howells8feae132009-01-08 12:04:47 +0000871 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872 }
873
874 return NULL;
875}
876
David Howells30340972006-09-27 01:50:20 -0700877/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 * determine whether a mapping should be permitted and, if so, what sort of
879 * mapping we're capable of supporting
880 */
881static int validate_mmap_request(struct file *file,
882 unsigned long addr,
883 unsigned long len,
884 unsigned long prot,
885 unsigned long flags,
886 unsigned long pgoff,
887 unsigned long *_capabilities)
888{
David Howells8feae132009-01-08 12:04:47 +0000889 unsigned long capabilities, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890 unsigned long reqprot = prot;
891 int ret;
892
893 /* do the simple checks first */
David Howells06aab5a2009-09-24 12:33:48 +0100894 if (flags & MAP_FIXED) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 printk(KERN_DEBUG
896 "%d: Can't do fixed-address/overlay mmap of RAM\n",
897 current->pid);
898 return -EINVAL;
899 }
900
901 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
902 (flags & MAP_TYPE) != MAP_SHARED)
903 return -EINVAL;
904
Mike Frysingerf81cff02006-12-06 12:02:59 +1000905 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 return -EINVAL;
907
Mike Frysingerf81cff02006-12-06 12:02:59 +1000908 /* Careful about overflows.. */
David Howells8feae132009-01-08 12:04:47 +0000909 rlen = PAGE_ALIGN(len);
910 if (!rlen || rlen > TASK_SIZE)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000911 return -ENOMEM;
912
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 /* offset overflow? */
David Howells8feae132009-01-08 12:04:47 +0000914 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000915 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916
917 if (file) {
918 /* validate file mapping requests */
919 struct address_space *mapping;
920
921 /* files must support mmap */
922 if (!file->f_op || !file->f_op->mmap)
923 return -ENODEV;
924
925 /* work out if what we've got could possibly be shared
926 * - we support chardevs that provide their own "memory"
927 * - we support files/blockdevs that are memory backed
928 */
929 mapping = file->f_mapping;
930 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800931 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932
933 capabilities = 0;
934 if (mapping && mapping->backing_dev_info)
935 capabilities = mapping->backing_dev_info->capabilities;
936
937 if (!capabilities) {
938 /* no explicit capabilities set, so assume some
939 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800940 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 case S_IFREG:
942 case S_IFBLK:
943 capabilities = BDI_CAP_MAP_COPY;
944 break;
945
946 case S_IFCHR:
947 capabilities =
948 BDI_CAP_MAP_DIRECT |
949 BDI_CAP_READ_MAP |
950 BDI_CAP_WRITE_MAP;
951 break;
952
953 default:
954 return -EINVAL;
955 }
956 }
957
958 /* eliminate any capabilities that we can't support on this
959 * device */
960 if (!file->f_op->get_unmapped_area)
961 capabilities &= ~BDI_CAP_MAP_DIRECT;
962 if (!file->f_op->read)
963 capabilities &= ~BDI_CAP_MAP_COPY;
964
Graff Yang28d7a6a2009-08-18 14:11:17 -0700965 /* The file shall have been opened with read permission. */
966 if (!(file->f_mode & FMODE_READ))
967 return -EACCES;
968
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969 if (flags & MAP_SHARED) {
970 /* do checks for writing, appending and locking */
971 if ((prot & PROT_WRITE) &&
972 !(file->f_mode & FMODE_WRITE))
973 return -EACCES;
974
Josef Sipeke9536ae2006-12-08 02:37:21 -0800975 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 (file->f_mode & FMODE_WRITE))
977 return -EACCES;
978
Josef Sipeke9536ae2006-12-08 02:37:21 -0800979 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980 return -EAGAIN;
981
982 if (!(capabilities & BDI_CAP_MAP_DIRECT))
983 return -ENODEV;
984
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985 /* we mustn't privatise shared mappings */
986 capabilities &= ~BDI_CAP_MAP_COPY;
987 }
988 else {
989 /* we're going to read the file into private memory we
990 * allocate */
991 if (!(capabilities & BDI_CAP_MAP_COPY))
992 return -ENODEV;
993
994 /* we don't permit a private writable mapping to be
995 * shared with the backing device */
996 if (prot & PROT_WRITE)
997 capabilities &= ~BDI_CAP_MAP_DIRECT;
998 }
999
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001000 if (capabilities & BDI_CAP_MAP_DIRECT) {
1001 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
1002 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
1003 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
1004 ) {
1005 capabilities &= ~BDI_CAP_MAP_DIRECT;
1006 if (flags & MAP_SHARED) {
1007 printk(KERN_WARNING
1008 "MAP_SHARED not completely supported on !MMU\n");
1009 return -EINVAL;
1010 }
1011 }
1012 }
1013
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 /* handle executable mappings and implied executable
1015 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -08001016 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 if (prot & PROT_EXEC)
1018 return -EPERM;
1019 }
1020 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
1021 /* handle implication of PROT_EXEC by PROT_READ */
1022 if (current->personality & READ_IMPLIES_EXEC) {
1023 if (capabilities & BDI_CAP_EXEC_MAP)
1024 prot |= PROT_EXEC;
1025 }
1026 }
1027 else if ((prot & PROT_READ) &&
1028 (prot & PROT_EXEC) &&
1029 !(capabilities & BDI_CAP_EXEC_MAP)
1030 ) {
1031 /* backing file is not executable, try to copy */
1032 capabilities &= ~BDI_CAP_MAP_DIRECT;
1033 }
1034 }
1035 else {
1036 /* anonymous mappings are always memory backed and can be
1037 * privately mapped
1038 */
1039 capabilities = BDI_CAP_MAP_COPY;
1040
1041 /* handle PROT_EXEC implication by PROT_READ */
1042 if ((prot & PROT_READ) &&
1043 (current->personality & READ_IMPLIES_EXEC))
1044 prot |= PROT_EXEC;
1045 }
1046
1047 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -04001048 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 if (ret < 0)
1050 return ret;
1051
1052 /* looks okay */
1053 *_capabilities = capabilities;
1054 return 0;
1055}
1056
1057/*
1058 * we've determined that we can make the mapping, now translate what we
1059 * now know into VMA flags
1060 */
1061static unsigned long determine_vm_flags(struct file *file,
1062 unsigned long prot,
1063 unsigned long flags,
1064 unsigned long capabilities)
1065{
1066 unsigned long vm_flags;
1067
1068 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 /* vm_flags |= mm->def_flags; */
1070
1071 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1072 /* attempt to share read-only copies of mapped file chunks */
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001073 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 if (file && !(prot & PROT_WRITE))
1075 vm_flags |= VM_MAYSHARE;
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001076 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 /* overlay a shareable mapping on the backing device or inode
1078 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1079 * romfs/cramfs */
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001080 vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 if (flags & MAP_SHARED)
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001082 vm_flags |= VM_SHARED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 }
1084
1085 /* refuse to let anyone share private mappings with this process if
1086 * it's being traced - otherwise breakpoints set in it may interfere
1087 * with another untraced process
1088 */
Tejun Heoa288eec2011-06-17 16:50:37 +02001089 if ((flags & MAP_PRIVATE) && current->ptrace)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 vm_flags &= ~VM_MAYSHARE;
1091
1092 return vm_flags;
1093}
1094
1095/*
David Howells8feae132009-01-08 12:04:47 +00001096 * set up a shared mapping on a file (the driver or filesystem provides and
1097 * pins the storage)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 */
David Howells8feae132009-01-08 12:04:47 +00001099static int do_mmap_shared_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100{
1101 int ret;
1102
1103 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001104 if (ret == 0) {
1105 vma->vm_region->vm_top = vma->vm_region->vm_end;
David Howells645d83c2009-09-24 15:13:10 +01001106 return 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001107 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 if (ret != -ENOSYS)
1109 return ret;
1110
David Howells3fa30462010-03-23 13:35:21 -07001111 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1112 * opposed to tried but failed) so we can only give a suitable error as
1113 * it's not possible to make a private copy if MAP_SHARED was given */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114 return -ENODEV;
1115}
1116
1117/*
1118 * set up a private mapping or an anonymous shared mapping
1119 */
David Howells8feae132009-01-08 12:04:47 +00001120static int do_mmap_private(struct vm_area_struct *vma,
1121 struct vm_region *region,
David Howells645d83c2009-09-24 15:13:10 +01001122 unsigned long len,
1123 unsigned long capabilities)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001124{
David Howells8feae132009-01-08 12:04:47 +00001125 struct page *pages;
Bob Liuf67d9b12011-05-24 17:12:56 -07001126 unsigned long total, point, n;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 void *base;
David Howells8feae132009-01-08 12:04:47 +00001128 int ret, order;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129
1130 /* invoke the file's mapping function so that it can keep track of
1131 * shared mappings on devices or memory
1132 * - VM_MAYSHARE will be set if it may attempt to share
1133 */
David Howells645d83c2009-09-24 15:13:10 +01001134 if (capabilities & BDI_CAP_MAP_DIRECT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001136 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001137 /* shouldn't return success if we're not sharing */
Paul Mundtdd8632a2009-01-08 12:04:47 +00001138 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1139 vma->vm_region->vm_top = vma->vm_region->vm_end;
David Howells645d83c2009-09-24 15:13:10 +01001140 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 }
Paul Mundtdd8632a2009-01-08 12:04:47 +00001142 if (ret != -ENOSYS)
1143 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144
1145 /* getting an ENOSYS error indicates that direct mmap isn't
1146 * possible (as opposed to tried but failed) so we'll try to
1147 * make a private copy of the data and map that instead */
1148 }
1149
David Howells8feae132009-01-08 12:04:47 +00001150
Linus Torvalds1da177e2005-04-16 15:20:36 -07001151 /* allocate some memory to hold the mapping
1152 * - note that this may not return a page-aligned address if the object
1153 * we're allocating is smaller than a page
1154 */
Bob Liuf67d9b12011-05-24 17:12:56 -07001155 order = get_order(len);
David Howells8feae132009-01-08 12:04:47 +00001156 kdebug("alloc order %d for %lx", order, len);
1157
1158 pages = alloc_pages(GFP_KERNEL, order);
1159 if (!pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160 goto enomem;
1161
David Howells8feae132009-01-08 12:04:47 +00001162 total = 1 << order;
David Howells33e5d7692009-04-02 16:56:32 -07001163 atomic_long_add(total, &mmap_pages_allocated);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164
Bob Liuf67d9b12011-05-24 17:12:56 -07001165 point = len >> PAGE_SHIFT;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001166
1167 /* we allocated a power-of-2 sized page set, so we may want to trim off
1168 * the excess */
1169 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1170 while (total > point) {
1171 order = ilog2(total - point);
1172 n = 1 << order;
1173 kdebug("shave %lu/%lu @%lu", n, total - point, total);
David Howells33e5d7692009-04-02 16:56:32 -07001174 atomic_long_sub(n, &mmap_pages_allocated);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001175 total -= n;
1176 set_page_refcounted(pages + total);
1177 __free_pages(pages + total, order);
1178 }
David Howells8feae132009-01-08 12:04:47 +00001179 }
1180
David Howells8feae132009-01-08 12:04:47 +00001181 for (point = 1; point < total; point++)
1182 set_page_refcounted(&pages[point]);
1183
1184 base = page_address(pages);
1185 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1186 region->vm_start = (unsigned long) base;
Bob Liuf67d9b12011-05-24 17:12:56 -07001187 region->vm_end = region->vm_start + len;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001188 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
David Howells8feae132009-01-08 12:04:47 +00001189
1190 vma->vm_start = region->vm_start;
1191 vma->vm_end = region->vm_start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192
1193 if (vma->vm_file) {
1194 /* read the contents of a file into the copy */
1195 mm_segment_t old_fs;
1196 loff_t fpos;
1197
1198 fpos = vma->vm_pgoff;
1199 fpos <<= PAGE_SHIFT;
1200
1201 old_fs = get_fs();
1202 set_fs(KERNEL_DS);
Bob Liuf67d9b12011-05-24 17:12:56 -07001203 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 set_fs(old_fs);
1205
1206 if (ret < 0)
1207 goto error_free;
1208
1209 /* clear the last little bit */
Bob Liuf67d9b12011-05-24 17:12:56 -07001210 if (ret < len)
1211 memset(base + ret, 0, len - ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001212
Linus Torvalds1da177e2005-04-16 15:20:36 -07001213 }
1214
1215 return 0;
1216
1217error_free:
Namhyung Kim7223bb42011-05-24 17:11:26 -07001218 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +00001219 region->vm_start = vma->vm_start = 0;
1220 region->vm_end = vma->vm_end = 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001221 region->vm_top = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 return ret;
1223
1224enomem:
Greg Ungerer05ae6fa2009-01-13 17:30:22 +10001225 printk("Allocation of length %lu from process %d (%s) failed\n",
1226 len, current->pid, current->comm);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001227 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 return -ENOMEM;
1229}
1230
1231/*
1232 * handle mapping creation for uClinux
1233 */
1234unsigned long do_mmap_pgoff(struct file *file,
1235 unsigned long addr,
1236 unsigned long len,
1237 unsigned long prot,
1238 unsigned long flags,
1239 unsigned long pgoff)
1240{
David Howells8feae132009-01-08 12:04:47 +00001241 struct vm_area_struct *vma;
1242 struct vm_region *region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 struct rb_node *rb;
David Howells8feae132009-01-08 12:04:47 +00001244 unsigned long capabilities, vm_flags, result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 int ret;
1246
David Howells8feae132009-01-08 12:04:47 +00001247 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1248
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 /* decide whether we should attempt the mapping, and if so what sort of
1250 * mapping */
1251 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1252 &capabilities);
David Howells8feae132009-01-08 12:04:47 +00001253 if (ret < 0) {
1254 kleave(" = %d [val]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 return ret;
David Howells8feae132009-01-08 12:04:47 +00001256 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257
David Howells06aab5a2009-09-24 12:33:48 +01001258 /* we ignore the address hint */
1259 addr = 0;
Bob Liuf67d9b12011-05-24 17:12:56 -07001260 len = PAGE_ALIGN(len);
David Howells06aab5a2009-09-24 12:33:48 +01001261
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 /* we've determined that we can make the mapping, now translate what we
1263 * now know into VMA flags */
1264 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1265
David Howells8feae132009-01-08 12:04:47 +00001266 /* we're going to need to record the mapping */
1267 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1268 if (!region)
1269 goto error_getting_region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270
David Howells8feae132009-01-08 12:04:47 +00001271 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1272 if (!vma)
1273 goto error_getting_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274
David Howells1e2ae592010-01-15 17:01:33 -08001275 region->vm_usage = 1;
David Howells8feae132009-01-08 12:04:47 +00001276 region->vm_flags = vm_flags;
1277 region->vm_pgoff = pgoff;
1278
Rik van Riel5beb4932010-03-05 13:42:07 -08001279 INIT_LIST_HEAD(&vma->anon_vma_chain);
David Howells8feae132009-01-08 12:04:47 +00001280 vma->vm_flags = vm_flags;
1281 vma->vm_pgoff = pgoff;
1282
1283 if (file) {
1284 region->vm_file = file;
1285 get_file(file);
1286 vma->vm_file = file;
1287 get_file(file);
1288 if (vm_flags & VM_EXECUTABLE) {
1289 added_exe_file_vma(current->mm);
1290 vma->vm_mm = current->mm;
1291 }
1292 }
1293
1294 down_write(&nommu_region_sem);
1295
1296 /* if we want to share, we need to check for regions created by other
Linus Torvalds1da177e2005-04-16 15:20:36 -07001297 * mmap() calls that overlap with our proposed mapping
David Howells8feae132009-01-08 12:04:47 +00001298 * - we can only share with a superset match on most regular files
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 * - shared mappings on character devices and memory backed files are
1300 * permitted to overlap inexactly as far as we are concerned for in
1301 * these cases, sharing is handled in the driver or filesystem rather
1302 * than here
1303 */
1304 if (vm_flags & VM_MAYSHARE) {
David Howells8feae132009-01-08 12:04:47 +00001305 struct vm_region *pregion;
1306 unsigned long pglen, rpglen, pgend, rpgend, start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307
David Howells8feae132009-01-08 12:04:47 +00001308 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1309 pgend = pgoff + pglen;
David Howells165b2392007-03-22 00:11:24 -08001310
David Howells8feae132009-01-08 12:04:47 +00001311 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1312 pregion = rb_entry(rb, struct vm_region, vm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313
David Howells8feae132009-01-08 12:04:47 +00001314 if (!(pregion->vm_flags & VM_MAYSHARE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 continue;
1316
1317 /* search for overlapping mappings on the same file */
David Howells8feae132009-01-08 12:04:47 +00001318 if (pregion->vm_file->f_path.dentry->d_inode !=
1319 file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320 continue;
1321
David Howells8feae132009-01-08 12:04:47 +00001322 if (pregion->vm_pgoff >= pgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 continue;
1324
David Howells8feae132009-01-08 12:04:47 +00001325 rpglen = pregion->vm_end - pregion->vm_start;
1326 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1327 rpgend = pregion->vm_pgoff + rpglen;
1328 if (pgoff >= rpgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329 continue;
1330
David Howells8feae132009-01-08 12:04:47 +00001331 /* handle inexactly overlapping matches between
1332 * mappings */
1333 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1334 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1335 /* new mapping is not a subset of the region */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1337 goto sharing_violation;
1338 continue;
1339 }
1340
David Howells8feae132009-01-08 12:04:47 +00001341 /* we've found a region we can share */
David Howells1e2ae592010-01-15 17:01:33 -08001342 pregion->vm_usage++;
David Howells8feae132009-01-08 12:04:47 +00001343 vma->vm_region = pregion;
1344 start = pregion->vm_start;
1345 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1346 vma->vm_start = start;
1347 vma->vm_end = start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348
David Howells8feae132009-01-08 12:04:47 +00001349 if (pregion->vm_flags & VM_MAPPED_COPY) {
1350 kdebug("share copy");
1351 vma->vm_flags |= VM_MAPPED_COPY;
1352 } else {
1353 kdebug("share mmap");
1354 ret = do_mmap_shared_file(vma);
1355 if (ret < 0) {
1356 vma->vm_region = NULL;
1357 vma->vm_start = 0;
1358 vma->vm_end = 0;
David Howells1e2ae592010-01-15 17:01:33 -08001359 pregion->vm_usage--;
David Howells8feae132009-01-08 12:04:47 +00001360 pregion = NULL;
1361 goto error_just_free;
1362 }
1363 }
1364 fput(region->vm_file);
1365 kmem_cache_free(vm_region_jar, region);
1366 region = pregion;
1367 result = start;
1368 goto share;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 }
1370
Linus Torvalds1da177e2005-04-16 15:20:36 -07001371 /* obtain the address at which to make a shared mapping
1372 * - this is the hook for quasi-memory character devices to
1373 * tell us the location of a shared mapping
1374 */
David Howells645d83c2009-09-24 15:13:10 +01001375 if (capabilities & BDI_CAP_MAP_DIRECT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001376 addr = file->f_op->get_unmapped_area(file, addr, len,
1377 pgoff, flags);
Namhyung Kimbb005a52011-05-24 17:11:27 -07001378 if (IS_ERR_VALUE(addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001379 ret = addr;
Namhyung Kimbb005a52011-05-24 17:11:27 -07001380 if (ret != -ENOSYS)
David Howells8feae132009-01-08 12:04:47 +00001381 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382
1383 /* the driver refused to tell us where to site
1384 * the mapping so we'll have to attempt to copy
1385 * it */
Namhyung Kimbb005a52011-05-24 17:11:27 -07001386 ret = -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 if (!(capabilities & BDI_CAP_MAP_COPY))
David Howells8feae132009-01-08 12:04:47 +00001388 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001389
1390 capabilities &= ~BDI_CAP_MAP_DIRECT;
David Howells8feae132009-01-08 12:04:47 +00001391 } else {
1392 vma->vm_start = region->vm_start = addr;
1393 vma->vm_end = region->vm_end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 }
1395 }
1396 }
1397
David Howells8feae132009-01-08 12:04:47 +00001398 vma->vm_region = region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399
David Howells645d83c2009-09-24 15:13:10 +01001400 /* set up the mapping
1401 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1402 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001403 if (file && vma->vm_flags & VM_SHARED)
David Howells8feae132009-01-08 12:04:47 +00001404 ret = do_mmap_shared_file(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 else
David Howells645d83c2009-09-24 15:13:10 +01001406 ret = do_mmap_private(vma, region, len, capabilities);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407 if (ret < 0)
David Howells645d83c2009-09-24 15:13:10 +01001408 goto error_just_free;
1409 add_nommu_region(region);
David Howells8feae132009-01-08 12:04:47 +00001410
Jie Zhangea637632009-12-14 18:00:02 -08001411 /* clear anonymous mappings that don't ask for uninitialized data */
1412 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1413 memset((void *)region->vm_start, 0,
1414 region->vm_end - region->vm_start);
1415
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416 /* okay... we have a mapping; now we have to register it */
David Howells8feae132009-01-08 12:04:47 +00001417 result = vma->vm_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 current->mm->total_vm += len >> PAGE_SHIFT;
1420
David Howells8feae132009-01-08 12:04:47 +00001421share:
1422 add_vma_to_mm(current->mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423
Mike Frysingercfe79c02010-01-06 17:23:23 +00001424 /* we flush the region from the icache only when the first executable
1425 * mapping of it is made */
1426 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1427 flush_icache_range(region->vm_start, region->vm_end);
1428 region->vm_icache_flushed = true;
1429 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430
Mike Frysingercfe79c02010-01-06 17:23:23 +00001431 up_write(&nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432
David Howells8feae132009-01-08 12:04:47 +00001433 kleave(" = %lx", result);
1434 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435
David Howells8feae132009-01-08 12:04:47 +00001436error_just_free:
1437 up_write(&nommu_region_sem);
1438error:
David Howells89a86402009-10-30 13:13:26 +00001439 if (region->vm_file)
1440 fput(region->vm_file);
David Howells8feae132009-01-08 12:04:47 +00001441 kmem_cache_free(vm_region_jar, region);
David Howells89a86402009-10-30 13:13:26 +00001442 if (vma->vm_file)
1443 fput(vma->vm_file);
David Howells8feae132009-01-08 12:04:47 +00001444 if (vma->vm_flags & VM_EXECUTABLE)
1445 removed_exe_file_vma(vma->vm_mm);
1446 kmem_cache_free(vm_area_cachep, vma);
1447 kleave(" = %d", ret);
1448 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449
David Howells8feae132009-01-08 12:04:47 +00001450sharing_violation:
1451 up_write(&nommu_region_sem);
1452 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1453 ret = -EINVAL;
1454 goto error;
1455
1456error_getting_vma:
1457 kmem_cache_free(vm_region_jar, region);
1458 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1459 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 len, current->pid);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001461 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462 return -ENOMEM;
1463
David Howells8feae132009-01-08 12:04:47 +00001464error_getting_region:
1465 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1466 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467 len, current->pid);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001468 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 return -ENOMEM;
1470}
Paul Mundtb5073172007-07-21 04:37:25 -07001471EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001473SYSCALL_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
Al Viro120a7952010-10-30 02:54:44 -04001480 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001481 if (!(flags & MAP_ANONYMOUS)) {
1482 file = fget(fd);
1483 if (!file)
1484 goto out;
1485 }
1486
1487 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1488
1489 down_write(&current->mm->mmap_sem);
1490 retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1491 up_write(&current->mm->mmap_sem);
1492
1493 if (file)
1494 fput(file);
1495out:
1496 return retval;
1497}
1498
Christoph Hellwiga4679372010-03-10 15:21:15 -08001499#ifdef __ARCH_WANT_SYS_OLD_MMAP
1500struct mmap_arg_struct {
1501 unsigned long addr;
1502 unsigned long len;
1503 unsigned long prot;
1504 unsigned long flags;
1505 unsigned long fd;
1506 unsigned long offset;
1507};
1508
1509SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1510{
1511 struct mmap_arg_struct a;
1512
1513 if (copy_from_user(&a, arg, sizeof(a)))
1514 return -EFAULT;
1515 if (a.offset & ~PAGE_MASK)
1516 return -EINVAL;
1517
1518 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1519 a.offset >> PAGE_SHIFT);
1520}
1521#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1522
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523/*
David Howells8feae132009-01-08 12:04:47 +00001524 * split a vma into two pieces at address 'addr', a new vma is allocated either
1525 * for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 */
David Howells8feae132009-01-08 12:04:47 +00001527int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1528 unsigned long addr, int new_below)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529{
David Howells8feae132009-01-08 12:04:47 +00001530 struct vm_area_struct *new;
1531 struct vm_region *region;
1532 unsigned long npages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533
David Howells8feae132009-01-08 12:04:47 +00001534 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535
David Howells779c1022010-01-15 17:01:34 -08001536 /* we're only permitted to split anonymous regions (these should have
1537 * only a single usage on the region) */
1538 if (vma->vm_file)
David Howells8feae132009-01-08 12:04:47 +00001539 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540
David Howells8feae132009-01-08 12:04:47 +00001541 if (mm->map_count >= sysctl_max_map_count)
1542 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543
David Howells8feae132009-01-08 12:04:47 +00001544 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1545 if (!region)
1546 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547
David Howells8feae132009-01-08 12:04:47 +00001548 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1549 if (!new) {
1550 kmem_cache_free(vm_region_jar, region);
1551 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552 }
David Howells8feae132009-01-08 12:04:47 +00001553
1554 /* most fields are the same, copy all, and then fixup */
1555 *new = *vma;
1556 *region = *vma->vm_region;
1557 new->vm_region = region;
1558
1559 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1560
1561 if (new_below) {
Paul Mundtdd8632a2009-01-08 12:04:47 +00001562 region->vm_top = region->vm_end = new->vm_end = addr;
David Howells8feae132009-01-08 12:04:47 +00001563 } else {
1564 region->vm_start = new->vm_start = addr;
1565 region->vm_pgoff = new->vm_pgoff += npages;
1566 }
1567
1568 if (new->vm_ops && new->vm_ops->open)
1569 new->vm_ops->open(new);
1570
1571 delete_vma_from_mm(vma);
1572 down_write(&nommu_region_sem);
1573 delete_nommu_region(vma->vm_region);
1574 if (new_below) {
1575 vma->vm_region->vm_start = vma->vm_start = addr;
1576 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1577 } else {
1578 vma->vm_region->vm_end = vma->vm_end = addr;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001579 vma->vm_region->vm_top = addr;
David Howells8feae132009-01-08 12:04:47 +00001580 }
1581 add_nommu_region(vma->vm_region);
1582 add_nommu_region(new->vm_region);
1583 up_write(&nommu_region_sem);
1584 add_vma_to_mm(mm, vma);
1585 add_vma_to_mm(mm, new);
1586 return 0;
1587}
1588
1589/*
1590 * shrink a VMA by removing the specified chunk from either the beginning or
1591 * the end
1592 */
1593static int shrink_vma(struct mm_struct *mm,
1594 struct vm_area_struct *vma,
1595 unsigned long from, unsigned long to)
1596{
1597 struct vm_region *region;
1598
1599 kenter("");
1600
1601 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1602 * and list */
1603 delete_vma_from_mm(vma);
1604 if (from > vma->vm_start)
1605 vma->vm_end = from;
1606 else
1607 vma->vm_start = to;
1608 add_vma_to_mm(mm, vma);
1609
1610 /* cut the backing region down to size */
1611 region = vma->vm_region;
David Howells1e2ae592010-01-15 17:01:33 -08001612 BUG_ON(region->vm_usage != 1);
David Howells8feae132009-01-08 12:04:47 +00001613
1614 down_write(&nommu_region_sem);
1615 delete_nommu_region(region);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001616 if (from > region->vm_start) {
1617 to = region->vm_top;
1618 region->vm_top = region->vm_end = from;
1619 } else {
David Howells8feae132009-01-08 12:04:47 +00001620 region->vm_start = to;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001621 }
David Howells8feae132009-01-08 12:04:47 +00001622 add_nommu_region(region);
1623 up_write(&nommu_region_sem);
1624
1625 free_page_series(from, to);
1626 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001627}
1628
David Howells30340972006-09-27 01:50:20 -07001629/*
1630 * release a mapping
David Howells8feae132009-01-08 12:04:47 +00001631 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1632 * VMA, though it need not cover the whole VMA
David Howells30340972006-09-27 01:50:20 -07001633 */
David Howells8feae132009-01-08 12:04:47 +00001634int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001635{
David Howells8feae132009-01-08 12:04:47 +00001636 struct vm_area_struct *vma;
Bob Liuf67d9b12011-05-24 17:12:56 -07001637 unsigned long end;
David Howells8feae132009-01-08 12:04:47 +00001638 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001639
David Howells8feae132009-01-08 12:04:47 +00001640 kenter(",%lx,%zx", start, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001641
Bob Liuf67d9b12011-05-24 17:12:56 -07001642 len = PAGE_ALIGN(len);
David Howells8feae132009-01-08 12:04:47 +00001643 if (len == 0)
1644 return -EINVAL;
1645
Bob Liuf67d9b12011-05-24 17:12:56 -07001646 end = start + len;
1647
David Howells8feae132009-01-08 12:04:47 +00001648 /* find the first potentially overlapping VMA */
1649 vma = find_vma(mm, start);
1650 if (!vma) {
David Howells33e5d7692009-04-02 16:56:32 -07001651 static int limit = 0;
1652 if (limit < 5) {
1653 printk(KERN_WARNING
1654 "munmap of memory not mmapped by process %d"
1655 " (%s): 0x%lx-0x%lx\n",
1656 current->pid, current->comm,
1657 start, start + len - 1);
1658 limit++;
1659 }
David Howells8feae132009-01-08 12:04:47 +00001660 return -EINVAL;
David Howells30340972006-09-27 01:50:20 -07001661 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662
David Howells8feae132009-01-08 12:04:47 +00001663 /* we're allowed to split an anonymous VMA but not a file-backed one */
1664 if (vma->vm_file) {
1665 do {
1666 if (start > vma->vm_start) {
1667 kleave(" = -EINVAL [miss]");
1668 return -EINVAL;
1669 }
1670 if (end == vma->vm_end)
1671 goto erase_whole_vma;
Namhyung Kimd75a3102011-05-24 17:11:25 -07001672 vma = vma->vm_next;
1673 } while (vma);
David Howells8feae132009-01-08 12:04:47 +00001674 kleave(" = -EINVAL [split file]");
1675 return -EINVAL;
1676 } else {
1677 /* the chunk must be a subset of the VMA found */
1678 if (start == vma->vm_start && end == vma->vm_end)
1679 goto erase_whole_vma;
1680 if (start < vma->vm_start || end > vma->vm_end) {
1681 kleave(" = -EINVAL [superset]");
1682 return -EINVAL;
1683 }
1684 if (start & ~PAGE_MASK) {
1685 kleave(" = -EINVAL [unaligned start]");
1686 return -EINVAL;
1687 }
1688 if (end != vma->vm_end && end & ~PAGE_MASK) {
1689 kleave(" = -EINVAL [unaligned split]");
1690 return -EINVAL;
1691 }
1692 if (start != vma->vm_start && end != vma->vm_end) {
1693 ret = split_vma(mm, vma, start, 1);
1694 if (ret < 0) {
1695 kleave(" = %d [split]", ret);
1696 return ret;
1697 }
1698 }
1699 return shrink_vma(mm, vma, start, end);
1700 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701
David Howells8feae132009-01-08 12:04:47 +00001702erase_whole_vma:
1703 delete_vma_from_mm(vma);
1704 delete_vma(mm, vma);
1705 kleave(" = 0");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 return 0;
1707}
Paul Mundtb5073172007-07-21 04:37:25 -07001708EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001710SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
David Howells30340972006-09-27 01:50:20 -07001711{
1712 int ret;
1713 struct mm_struct *mm = current->mm;
1714
1715 down_write(&mm->mmap_sem);
1716 ret = do_munmap(mm, addr, len);
1717 up_write(&mm->mmap_sem);
1718 return ret;
1719}
1720
1721/*
David Howells8feae132009-01-08 12:04:47 +00001722 * release all the mappings made in a process's VM space
David Howells30340972006-09-27 01:50:20 -07001723 */
David Howells8feae132009-01-08 12:04:47 +00001724void exit_mmap(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725{
David Howells8feae132009-01-08 12:04:47 +00001726 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001727
David Howells8feae132009-01-08 12:04:47 +00001728 if (!mm)
1729 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001730
David Howells8feae132009-01-08 12:04:47 +00001731 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732
David Howells8feae132009-01-08 12:04:47 +00001733 mm->total_vm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001734
David Howells8feae132009-01-08 12:04:47 +00001735 while ((vma = mm->mmap)) {
1736 mm->mmap = vma->vm_next;
1737 delete_vma_from_mm(vma);
1738 delete_vma(mm, vma);
Steven J. Magnani04c349612010-11-24 12:56:54 -08001739 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740 }
David Howells8feae132009-01-08 12:04:47 +00001741
1742 kleave("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743}
1744
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745unsigned long do_brk(unsigned long addr, unsigned long len)
1746{
1747 return -ENOMEM;
1748}
1749
1750/*
David Howells6fa5f802006-09-27 01:50:21 -07001751 * expand (or shrink) an existing mapping, potentially moving it at the same
1752 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753 *
David Howells6fa5f802006-09-27 01:50:21 -07001754 * under NOMMU conditions, we only permit changing a mapping's size, and only
David Howells8feae132009-01-08 12:04:47 +00001755 * as long as it stays within the region allocated by do_mmap_private() and the
1756 * block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757 *
David Howells6fa5f802006-09-27 01:50:21 -07001758 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 */
1760unsigned long do_mremap(unsigned long addr,
1761 unsigned long old_len, unsigned long new_len,
1762 unsigned long flags, unsigned long new_addr)
1763{
David Howells6fa5f802006-09-27 01:50:21 -07001764 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765
1766 /* insanity checks first */
Bob Liuf67d9b12011-05-24 17:12:56 -07001767 old_len = PAGE_ALIGN(old_len);
1768 new_len = PAGE_ALIGN(new_len);
David Howells8feae132009-01-08 12:04:47 +00001769 if (old_len == 0 || new_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 return (unsigned long) -EINVAL;
1771
David Howells8feae132009-01-08 12:04:47 +00001772 if (addr & ~PAGE_MASK)
1773 return -EINVAL;
1774
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 if (flags & MREMAP_FIXED && new_addr != addr)
1776 return (unsigned long) -EINVAL;
1777
David Howells8feae132009-01-08 12:04:47 +00001778 vma = find_vma_exact(current->mm, addr, old_len);
David Howells6fa5f802006-09-27 01:50:21 -07001779 if (!vma)
1780 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781
David Howells6fa5f802006-09-27 01:50:21 -07001782 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 return (unsigned long) -EFAULT;
1784
David Howells6fa5f802006-09-27 01:50:21 -07001785 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 return (unsigned long) -EPERM;
1787
David Howells8feae132009-01-08 12:04:47 +00001788 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 return (unsigned long) -ENOMEM;
1790
1791 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001792 vma->vm_end = vma->vm_start + new_len;
David Howells6fa5f802006-09-27 01:50:21 -07001793 return vma->vm_start;
1794}
Paul Mundtb5073172007-07-21 04:37:25 -07001795EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001796
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001797SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1798 unsigned long, new_len, unsigned long, flags,
1799 unsigned long, new_addr)
David Howells6fa5f802006-09-27 01:50:21 -07001800{
1801 unsigned long ret;
1802
1803 down_write(&current->mm->mmap_sem);
1804 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1805 up_write(&current->mm->mmap_sem);
1806 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807}
1808
Linus Torvalds6aab3412005-11-28 14:34:23 -08001809struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001810 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001811{
1812 return NULL;
1813}
1814
Bob Liu8f3b1322011-07-08 15:39:46 -07001815int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1816 unsigned long pfn, unsigned long size, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817{
Bob Liu8f3b1322011-07-08 15:39:46 -07001818 if (addr != (pfn << PAGE_SHIFT))
1819 return -EINVAL;
1820
1821 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001822 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001823}
Luke Yang22c4af42006-07-14 00:24:09 -07001824EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001825
Paul Mundtf905bc42008-02-04 22:29:59 -08001826int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1827 unsigned long pgoff)
1828{
1829 unsigned int size = vma->vm_end - vma->vm_start;
1830
1831 if (!(vma->vm_flags & VM_USERMAP))
1832 return -EINVAL;
1833
1834 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1835 vma->vm_end = vma->vm_start + size;
1836
1837 return 0;
1838}
1839EXPORT_SYMBOL(remap_vmalloc_range);
1840
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1842 unsigned long len, unsigned long pgoff, unsigned long flags)
1843{
1844 return -ENOMEM;
1845}
1846
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001847void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848{
1849}
1850
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851void unmap_mapping_range(struct address_space *mapping,
1852 loff_t const holebegin, loff_t const holelen,
1853 int even_cows)
1854{
1855}
Luke Yang22c4af42006-07-14 00:24:09 -07001856EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857
1858/*
1859 * Check that a process has enough memory to allocate a new virtual
1860 * mapping. 0 means there is enough memory for the allocation to
1861 * succeed and -ENOMEM implies there is not.
1862 *
1863 * We currently support three overcommit policies, which are set via the
1864 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1865 *
1866 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1867 * Additional code 2002 Jul 20 by Robert Love.
1868 *
1869 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1870 *
1871 * Note this is a helper function intended to be used by LSMs which
1872 * wish to use this logic.
1873 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001874int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875{
1876 unsigned long free, allowed;
1877
1878 vm_acct_memory(pages);
1879
1880 /*
1881 * Sometimes we want to use more memory than we have
1882 */
1883 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1884 return 0;
1885
1886 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
Dmitry Finkc15bef32011-07-25 17:12:19 -07001887 free = global_page_state(NR_FREE_PAGES);
1888 free += global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001889
Dmitry Finkc15bef32011-07-25 17:12:19 -07001890 /*
1891 * shmem pages shouldn't be counted as free in this
1892 * case, they can't be purged, only swapped out, and
1893 * that won't affect the overall amount of available
1894 * memory in the system.
1895 */
1896 free -= global_page_state(NR_SHMEM);
1897
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 free += nr_swap_pages;
1899
1900 /*
1901 * Any slabs which are created with the
1902 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1903 * which are reclaimable, under pressure. The dentry
1904 * cache and most inode caches should fall into this
1905 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001906 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001907
1908 /*
Dmitry Finkc15bef32011-07-25 17:12:19 -07001909 * Leave reserved pages. The pages are not for anonymous pages.
1910 */
1911 if (free <= totalreserve_pages)
1912 goto error;
1913 else
1914 free -= totalreserve_pages;
1915
1916 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917 * Leave the last 3% for root
1918 */
1919 if (!cap_sys_admin)
1920 free -= free / 32;
1921
1922 if (free > pages)
1923 return 0;
1924
Hideo AOKId5ddc792006-04-10 22:53:01 -07001925 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 }
1927
1928 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1929 /*
1930 * Leave the last 3% for root
1931 */
1932 if (!cap_sys_admin)
1933 allowed -= allowed / 32;
1934 allowed += total_swap_pages;
1935
1936 /* Don't let a single process grow too big:
1937 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -07001938 if (mm)
1939 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001941 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001942 return 0;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001943
Hideo AOKId5ddc792006-04-10 22:53:01 -07001944error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 vm_unacct_memory(pages);
1946
1947 return -ENOMEM;
1948}
1949
Stephen Wilsoncae5d392011-03-13 15:49:17 -04001950int in_gate_area_no_mm(unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001951{
1952 return 0;
1953}
David Howellsb0e15192006-01-06 00:11:42 -08001954
Nick Piggind0217ac2007-07-19 01:47:03 -07001955int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001956{
1957 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001958 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001959}
Paul Mundtb5073172007-07-21 04:37:25 -07001960EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001961
Mike Frysingerf55f1992011-03-29 14:05:12 +01001962static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1963 unsigned long addr, void *buf, int len, int write)
David Howells0ec76a12006-09-27 01:50:15 -07001964{
David Howells0ec76a12006-09-27 01:50:15 -07001965 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07001966
1967 down_read(&mm->mmap_sem);
1968
1969 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001970 vma = find_vma(mm, addr);
1971 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001972 /* don't overrun this mapping */
1973 if (addr + len >= vma->vm_end)
1974 len = vma->vm_end - addr;
1975
1976 /* only read or write mappings where it is permitted */
David Howellsd00c7b92006-09-27 01:50:19 -07001977 if (write && vma->vm_flags & VM_MAYWRITE)
Jie Zhang79597222010-01-06 17:23:28 +00001978 copy_to_user_page(vma, NULL, addr,
1979 (void *) addr, buf, len);
David Howellsd00c7b92006-09-27 01:50:19 -07001980 else if (!write && vma->vm_flags & VM_MAYREAD)
Jie Zhang79597222010-01-06 17:23:28 +00001981 copy_from_user_page(vma, NULL, addr,
1982 buf, (void *) addr, len);
David Howells0ec76a12006-09-27 01:50:15 -07001983 else
1984 len = 0;
1985 } else {
1986 len = 0;
1987 }
1988
1989 up_read(&mm->mmap_sem);
Mike Frysingerf55f1992011-03-29 14:05:12 +01001990
1991 return len;
1992}
1993
1994/**
1995 * @access_remote_vm - access another process' address space
1996 * @mm: the mm_struct of the target address space
1997 * @addr: start address to access
1998 * @buf: source or destination buffer
1999 * @len: number of bytes to transfer
2000 * @write: whether the access is a write
2001 *
2002 * The caller must hold a reference on @mm.
2003 */
2004int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2005 void *buf, int len, int write)
2006{
2007 return __access_remote_vm(NULL, mm, addr, buf, len, write);
2008}
2009
2010/*
2011 * Access another process' address space.
2012 * - source/target buffer must be kernel space
2013 */
2014int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2015{
2016 struct mm_struct *mm;
2017
2018 if (addr + len < addr)
2019 return 0;
2020
2021 mm = get_task_mm(tsk);
2022 if (!mm)
2023 return 0;
2024
2025 len = __access_remote_vm(tsk, mm, addr, buf, len, write);
2026
David Howells0ec76a12006-09-27 01:50:15 -07002027 mmput(mm);
2028 return len;
2029}
David Howells7e660872010-01-15 17:01:39 -08002030
2031/**
2032 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
2033 * @inode: The inode to check
2034 * @size: The current filesize of the inode
2035 * @newsize: The proposed filesize of the inode
2036 *
2037 * Check the shared mappings on an inode on behalf of a shrinking truncate to
2038 * make sure that that any outstanding VMAs aren't broken and then shrink the
2039 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
2040 * automatically grant mappings that are too large.
2041 */
2042int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
2043 size_t newsize)
2044{
2045 struct vm_area_struct *vma;
2046 struct prio_tree_iter iter;
2047 struct vm_region *region;
2048 pgoff_t low, high;
2049 size_t r_size, r_top;
2050
2051 low = newsize >> PAGE_SHIFT;
2052 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2053
2054 down_write(&nommu_region_sem);
2055
2056 /* search for VMAs that fall within the dead zone */
2057 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
2058 low, high) {
2059 /* found one - only interested if it's shared out of the page
2060 * cache */
2061 if (vma->vm_flags & VM_SHARED) {
2062 up_write(&nommu_region_sem);
2063 return -ETXTBSY; /* not quite true, but near enough */
2064 }
2065 }
2066
2067 /* reduce any regions that overlap the dead zone - if in existence,
2068 * these will be pointed to by VMAs that don't overlap the dead zone
2069 *
2070 * we don't check for any regions that start beyond the EOF as there
2071 * shouldn't be any
2072 */
2073 vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
2074 0, ULONG_MAX) {
2075 if (!(vma->vm_flags & VM_SHARED))
2076 continue;
2077
2078 region = vma->vm_region;
2079 r_size = region->vm_top - region->vm_start;
2080 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
2081
2082 if (r_top > newsize) {
2083 region->vm_top -= r_top - newsize;
2084 if (region->vm_end > region->vm_top)
2085 region->vm_end = region->vm_top;
2086 }
2087 }
2088
2089 up_write(&nommu_region_sem);
2090 return 0;
2091}