blob: fec093adad9c1d65799206805f3d95fe19a1da88 [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
Paul Gortmakerb95f1b312011-10-16 02:01:52 -040016#include <linux/export.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>
Clark Williamscf4aebc22013-02-07 09:46:59 -060032#include <linux/sched/sysctl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070033
34#include <asm/uaccess.h>
35#include <asm/tlb.h>
36#include <asm/tlbflush.h>
Bernd Schmidteb8cdec2009-09-21 17:03:57 -070037#include <asm/mmu_context.h>
David Howells8feae132009-01-08 12:04:47 +000038#include "internal.h"
39
David Howells8feae132009-01-08 12:04:47 +000040#if 0
41#define kenter(FMT, ...) \
42 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
43#define kleave(FMT, ...) \
44 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
45#define kdebug(FMT, ...) \
46 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
47#else
48#define kenter(FMT, ...) \
49 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
50#define kleave(FMT, ...) \
51 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
52#define kdebug(FMT, ...) \
53 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
54#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56void *high_memory;
57struct page *mem_map;
58unsigned long max_mapnr;
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;
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -070065unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -070066unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
Linus Torvalds1da177e2005-04-16 15:20:36 -070067int heap_stack_gap = 0;
68
David Howells33e5d7692009-04-02 16:56:32 -070069atomic_long_t mmap_pages_allocated;
David Howells8feae132009-01-08 12:04:47 +000070
K. Y. Srinivasan997071b2012-11-15 14:34:42 -080071/*
72 * The global memory commitment made in the system can be a metric
73 * that can be used to drive ballooning decisions when Linux is hosted
74 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
75 * balancing memory across competing virtual machines that are hosted.
76 * Several metrics drive this policy engine including the guest reported
77 * memory commitment.
78 */
79unsigned long vm_memory_committed(void)
80{
81 return percpu_counter_read_positive(&vm_committed_as);
82}
83
84EXPORT_SYMBOL_GPL(vm_memory_committed);
85
Linus Torvalds1da177e2005-04-16 15:20:36 -070086EXPORT_SYMBOL(mem_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
David Howells8feae132009-01-08 12:04:47 +000088/* list of mapped, potentially shareable regions */
89static struct kmem_cache *vm_region_jar;
90struct rb_root nommu_region_tree = RB_ROOT;
91DECLARE_RWSEM(nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092
Alexey Dobriyanf0f37e22009-09-27 22:29:37 +040093const struct vm_operations_struct generic_file_vm_ops = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070094};
95
96/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070097 * Return the total memory allocated for this pointer, not
98 * just what the caller asked for.
99 *
100 * Doesn't have to be accurate, i.e. may have races.
101 */
102unsigned int kobjsize(const void *objp)
103{
104 struct page *page;
105
Michael Hennerich4016a132008-04-28 02:13:38 -0700106 /*
107 * If the object we have should not have ksize performed on it,
108 * return size of 0
109 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900110 if (!objp || !virt_addr_valid(objp))
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700111 return 0;
112
113 page = virt_to_head_page(objp);
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700114
115 /*
116 * If the allocator sets PageSlab, we know the pointer came from
117 * kmalloc().
118 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119 if (PageSlab(page))
120 return ksize(objp);
121
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700122 /*
Paul Mundtab2e83e2009-01-08 12:04:48 +0000123 * If it's not a compound page, see if we have a matching VMA
124 * region. This test is intentionally done in reverse order,
125 * so if there's no VMA, we still fall through and hand back
126 * PAGE_SIZE for 0-order pages.
127 */
128 if (!PageCompound(page)) {
129 struct vm_area_struct *vma;
130
131 vma = find_vma(current->mm, (unsigned long)objp);
132 if (vma)
133 return vma->vm_end - vma->vm_start;
134 }
135
136 /*
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700137 * The ksize() function is only guaranteed to work for pointers
Paul Mundt5a1603b2008-06-12 16:29:55 +0900138 * returned by kmalloc(). So handle arbitrary pointers here.
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700139 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900140 return PAGE_SIZE << compound_order(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141}
142
Michel Lespinasse28a35712013-02-22 16:35:55 -0800143long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
144 unsigned long start, unsigned long nr_pages,
145 unsigned int foll_flags, struct page **pages,
146 struct vm_area_struct **vmas, int *nonblocking)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700148 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700149 unsigned long vm_flags;
150 int i;
151
152 /* calculate required read or write permissions.
Hugh Dickins58fa8792009-09-21 17:03:31 -0700153 * If FOLL_FORCE is set, we only require the "MAY" flags.
David Howells7b4d5b82006-09-27 01:50:18 -0700154 */
Hugh Dickins58fa8792009-09-21 17:03:31 -0700155 vm_flags = (foll_flags & FOLL_WRITE) ?
156 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
157 vm_flags &= (foll_flags & FOLL_FORCE) ?
158 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
Peter Zijlstra9d737772009-06-25 11:58:55 +0200160 for (i = 0; i < nr_pages; i++) {
David Howells7561e8c2010-03-25 16:48:38 +0000161 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700162 if (!vma)
163 goto finish_or_fault;
164
165 /* protect what we can, including chardevs */
Hugh Dickins1c3aff12009-09-21 17:03:24 -0700166 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
167 !(vm_flags & vma->vm_flags))
David Howells7b4d5b82006-09-27 01:50:18 -0700168 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700169
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 if (pages) {
171 pages[i] = virt_to_page(start);
172 if (pages[i])
173 page_cache_get(pages[i]);
174 }
175 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700176 vmas[i] = vma;
David Howellse1ee65d2010-03-25 16:48:44 +0000177 start = (start + PAGE_SIZE) & PAGE_MASK;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178 }
David Howells7b4d5b82006-09-27 01:50:18 -0700179
180 return i;
181
182finish_or_fault:
183 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700184}
Nick Pigginb291f002008-10-18 20:26:44 -0700185
Nick Pigginb291f002008-10-18 20:26:44 -0700186/*
187 * get a list of pages in an address range belonging to the specified process
188 * and indicate the VMA that covers each page
189 * - this is potentially dodgy as we may end incrementing the page count of a
190 * slab page or a secondary page from a compound page
191 * - don't permit access to VMAs that don't support it, such as I/O mappings
192 */
Michel Lespinasse28a35712013-02-22 16:35:55 -0800193long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
194 unsigned long start, unsigned long nr_pages,
195 int write, int force, struct page **pages,
196 struct vm_area_struct **vmas)
Nick Pigginb291f002008-10-18 20:26:44 -0700197{
198 int flags = 0;
199
200 if (write)
Hugh Dickins58fa8792009-09-21 17:03:31 -0700201 flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -0700202 if (force)
Hugh Dickins58fa8792009-09-21 17:03:31 -0700203 flags |= FOLL_FORCE;
Nick Pigginb291f002008-10-18 20:26:44 -0700204
Michel Lespinasse53a77062011-01-13 15:46:14 -0800205 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
206 NULL);
Nick Pigginb291f002008-10-18 20:26:44 -0700207}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000208EXPORT_SYMBOL(get_user_pages);
209
Paul Mundtdfc2f912009-06-26 04:31:57 +0900210/**
211 * follow_pfn - look up PFN at a user virtual address
212 * @vma: memory mapping
213 * @address: user virtual address
214 * @pfn: location to store found PFN
215 *
216 * Only IO mappings and raw PFN mappings are allowed.
217 *
218 * Returns zero and the pfn at @pfn on success, -ve otherwise.
219 */
220int follow_pfn(struct vm_area_struct *vma, unsigned long address,
221 unsigned long *pfn)
222{
223 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
224 return -EINVAL;
225
226 *pfn = address >> PAGE_SHIFT;
227 return 0;
228}
229EXPORT_SYMBOL(follow_pfn);
230
Joonsoo Kimf1c40692013-04-29 15:07:37 -0700231LIST_HEAD(vmap_area_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800233void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700234{
235 kfree(addr);
236}
Paul Mundtb5073172007-07-21 04:37:25 -0700237EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238
Al Virodd0fc662005-10-07 07:46:04 +0100239void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240{
241 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200242 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
243 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 */
Nick Piggin84097512006-03-22 00:08:34 -0800245 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246}
Paul Mundtb5073172007-07-21 04:37:25 -0700247EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
Paul Mundtf905bc42008-02-04 22:29:59 -0800249void *vmalloc_user(unsigned long size)
250{
251 void *ret;
252
253 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
254 PAGE_KERNEL);
255 if (ret) {
256 struct vm_area_struct *vma;
257
258 down_write(&current->mm->mmap_sem);
259 vma = find_vma(current->mm, (unsigned long)ret);
260 if (vma)
261 vma->vm_flags |= VM_USERMAP;
262 up_write(&current->mm->mmap_sem);
263 }
264
265 return ret;
266}
267EXPORT_SYMBOL(vmalloc_user);
268
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800269struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270{
271 return virt_to_page(addr);
272}
Paul Mundtb5073172007-07-21 04:37:25 -0700273EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800275unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276{
277 return page_to_pfn(virt_to_page(addr));
278}
Paul Mundtb5073172007-07-21 04:37:25 -0700279EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280
281long vread(char *buf, char *addr, unsigned long count)
282{
Chen Gang9bde9162013-07-03 15:02:36 -0700283 /* Don't allow overflow */
284 if ((unsigned long) buf + count < count)
285 count = -(unsigned long) buf;
286
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287 memcpy(buf, addr, count);
288 return count;
289}
290
291long vwrite(char *buf, char *addr, unsigned long count)
292{
293 /* Don't allow overflow */
294 if ((unsigned long) addr + count < count)
295 count = -(unsigned long) addr;
296
297 memcpy(addr, buf, count);
298 return(count);
299}
300
301/*
302 * vmalloc - allocate virtually continguos memory
303 *
304 * @size: allocation size
305 *
306 * Allocate enough pages to cover @size from the page level
307 * allocator and map them into continguos kernel virtual space.
308 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200309 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 * use __vmalloc() instead.
311 */
312void *vmalloc(unsigned long size)
313{
314 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
315}
Andrew Mortonf6138882006-02-28 16:59:18 -0800316EXPORT_SYMBOL(vmalloc);
317
Dave Younge1ca7782010-10-26 14:22:06 -0700318/*
319 * vzalloc - allocate virtually continguos memory with zero fill
320 *
321 * @size: allocation size
322 *
323 * Allocate enough pages to cover @size from the page level
324 * allocator and map them into continguos kernel virtual space.
325 * The memory allocated is set to zero.
326 *
327 * For tight control over page level allocator and protection flags
328 * use __vmalloc() instead.
329 */
330void *vzalloc(unsigned long size)
331{
332 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
333 PAGE_KERNEL);
334}
335EXPORT_SYMBOL(vzalloc);
336
337/**
338 * vmalloc_node - allocate memory on a specific node
339 * @size: allocation size
340 * @node: numa node
341 *
342 * Allocate enough pages to cover @size from the page level
343 * allocator and map them into contiguous kernel virtual space.
344 *
345 * For tight control over page level allocator and protection flags
346 * use __vmalloc() instead.
347 */
Andrew Mortonf6138882006-02-28 16:59:18 -0800348void *vmalloc_node(unsigned long size, int node)
349{
350 return vmalloc(size);
351}
Paul Mundt9a14f652010-12-24 11:50:34 +0900352EXPORT_SYMBOL(vmalloc_node);
Dave Younge1ca7782010-10-26 14:22:06 -0700353
354/**
355 * vzalloc_node - allocate memory on a specific node with zero fill
356 * @size: allocation size
357 * @node: numa node
358 *
359 * Allocate enough pages to cover @size from the page level
360 * allocator and map them into contiguous kernel virtual space.
361 * The memory allocated is set to zero.
362 *
363 * For tight control over page level allocator and protection flags
364 * use __vmalloc() instead.
365 */
366void *vzalloc_node(unsigned long size, int node)
367{
368 return vzalloc(size);
369}
370EXPORT_SYMBOL(vzalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371
Paul Mundt1af446e2008-08-04 16:01:47 +0900372#ifndef PAGE_KERNEL_EXEC
373# define PAGE_KERNEL_EXEC PAGE_KERNEL
374#endif
375
376/**
377 * vmalloc_exec - allocate virtually contiguous, executable memory
378 * @size: allocation size
379 *
380 * Kernel-internal function to allocate enough pages to cover @size
381 * the page level allocator and map them into contiguous and
382 * executable kernel virtual space.
383 *
384 * For tight control over page level allocator and protection flags
385 * use __vmalloc() instead.
386 */
387
388void *vmalloc_exec(unsigned long size)
389{
390 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
391}
392
Paul Mundtb5073172007-07-21 04:37:25 -0700393/**
394 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 * @size: allocation size
396 *
397 * Allocate enough 32bit PA addressable pages to cover @size from the
398 * page level allocator and map them into continguos kernel virtual space.
399 */
400void *vmalloc_32(unsigned long size)
401{
402 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
403}
Paul Mundtb5073172007-07-21 04:37:25 -0700404EXPORT_SYMBOL(vmalloc_32);
405
406/**
407 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
408 * @size: allocation size
409 *
410 * The resulting memory area is 32bit addressable and zeroed so it can be
411 * mapped to userspace without leaking data.
Paul Mundtf905bc42008-02-04 22:29:59 -0800412 *
413 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
414 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700415 */
416void *vmalloc_32_user(unsigned long size)
417{
Paul Mundtf905bc42008-02-04 22:29:59 -0800418 /*
419 * We'll have to sort out the ZONE_DMA bits for 64-bit,
420 * but for now this can simply use vmalloc_user() directly.
421 */
422 return vmalloc_user(size);
Paul Mundtb5073172007-07-21 04:37:25 -0700423}
424EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425
426void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
427{
428 BUG();
429 return NULL;
430}
Paul Mundtb5073172007-07-21 04:37:25 -0700431EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800433void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434{
435 BUG();
436}
Paul Mundtb5073172007-07-21 04:37:25 -0700437EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438
Paul Mundteb6434d2009-01-21 17:45:47 +0900439void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
440{
441 BUG();
442 return NULL;
443}
444EXPORT_SYMBOL(vm_map_ram);
445
446void vm_unmap_ram(const void *mem, unsigned int count)
447{
448 BUG();
449}
450EXPORT_SYMBOL(vm_unmap_ram);
451
452void vm_unmap_aliases(void)
453{
454}
455EXPORT_SYMBOL_GPL(vm_unmap_aliases);
456
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700458 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
459 * have one.
460 */
461void __attribute__((weak)) vmalloc_sync_all(void)
462{
463}
464
Paul Mundt29c185e2010-12-24 12:08:30 +0900465/**
466 * alloc_vm_area - allocate a range of kernel address space
467 * @size: size of the area
468 *
469 * Returns: NULL on failure, vm_struct on success
470 *
471 * This function reserves a range of kernel address space, and
472 * allocates pagetables to map that range. No actual mappings
473 * are created. If the kernel address space is not shared
474 * between processes, it syncs the pagetable across all
475 * processes.
476 */
David Vrabelcd129092011-09-29 16:53:32 +0100477struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
Paul Mundt29c185e2010-12-24 12:08:30 +0900478{
479 BUG();
480 return NULL;
481}
482EXPORT_SYMBOL_GPL(alloc_vm_area);
483
484void free_vm_area(struct vm_struct *area)
485{
486 BUG();
487}
488EXPORT_SYMBOL_GPL(free_vm_area);
489
Paul Mundtb5073172007-07-21 04:37:25 -0700490int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
491 struct page *page)
492{
493 return -EINVAL;
494}
495EXPORT_SYMBOL(vm_insert_page);
496
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700497/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 * sys_brk() for the most part doesn't need the global kernel
499 * lock, except when an application is doing something nasty
500 * like trying to un-brk an area that has already been mapped
501 * to a regular file. in this case, the unmapping will need
502 * to invoke file system routines that need the global lock.
503 */
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100504SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505{
506 struct mm_struct *mm = current->mm;
507
508 if (brk < mm->start_brk || brk > mm->context.end_brk)
509 return mm->brk;
510
511 if (mm->brk == brk)
512 return mm->brk;
513
514 /*
515 * Always allow shrinking brk
516 */
517 if (brk <= mm->brk) {
518 mm->brk = brk;
519 return brk;
520 }
521
522 /*
523 * Ok, looks good - let it rip.
524 */
Mike Frysingercfe79c02010-01-06 17:23:23 +0000525 flush_icache_range(mm->brk, brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 return mm->brk = brk;
527}
528
David Howells8feae132009-01-08 12:04:47 +0000529/*
530 * initialise the VMA and region record slabs
531 */
532void __init mmap_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700534 int ret;
535
536 ret = percpu_counter_init(&vm_committed_as, 0);
537 VM_BUG_ON(ret);
David Howells33e5d7692009-04-02 16:56:32 -0700538 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
David Howells8feae132009-01-08 12:04:47 +0000539}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
David Howells8feae132009-01-08 12:04:47 +0000541/*
542 * validate the region tree
543 * - the caller must hold the region lock
544 */
545#ifdef CONFIG_DEBUG_NOMMU_REGIONS
546static noinline void validate_nommu_regions(void)
547{
548 struct vm_region *region, *last;
549 struct rb_node *p, *lastp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550
David Howells8feae132009-01-08 12:04:47 +0000551 lastp = rb_first(&nommu_region_tree);
552 if (!lastp)
553 return;
554
555 last = rb_entry(lastp, struct vm_region, vm_rb);
David Howells33e5d7692009-04-02 16:56:32 -0700556 BUG_ON(unlikely(last->vm_end <= last->vm_start));
557 BUG_ON(unlikely(last->vm_top < last->vm_end));
David Howells8feae132009-01-08 12:04:47 +0000558
559 while ((p = rb_next(lastp))) {
560 region = rb_entry(p, struct vm_region, vm_rb);
561 last = rb_entry(lastp, struct vm_region, vm_rb);
562
David Howells33e5d7692009-04-02 16:56:32 -0700563 BUG_ON(unlikely(region->vm_end <= region->vm_start));
564 BUG_ON(unlikely(region->vm_top < region->vm_end));
565 BUG_ON(unlikely(region->vm_start < last->vm_top));
David Howells8feae132009-01-08 12:04:47 +0000566
567 lastp = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 }
569}
David Howells8feae132009-01-08 12:04:47 +0000570#else
David Howells33e5d7692009-04-02 16:56:32 -0700571static void validate_nommu_regions(void)
572{
573}
David Howells8feae132009-01-08 12:04:47 +0000574#endif
575
576/*
577 * add a region into the global tree
578 */
579static void add_nommu_region(struct vm_region *region)
580{
581 struct vm_region *pregion;
582 struct rb_node **p, *parent;
583
584 validate_nommu_regions();
585
David Howells8feae132009-01-08 12:04:47 +0000586 parent = NULL;
587 p = &nommu_region_tree.rb_node;
588 while (*p) {
589 parent = *p;
590 pregion = rb_entry(parent, struct vm_region, vm_rb);
591 if (region->vm_start < pregion->vm_start)
592 p = &(*p)->rb_left;
593 else if (region->vm_start > pregion->vm_start)
594 p = &(*p)->rb_right;
595 else if (pregion == region)
596 return;
597 else
598 BUG();
599 }
600
601 rb_link_node(&region->vm_rb, parent, p);
602 rb_insert_color(&region->vm_rb, &nommu_region_tree);
603
604 validate_nommu_regions();
605}
606
607/*
608 * delete a region from the global tree
609 */
610static void delete_nommu_region(struct vm_region *region)
611{
612 BUG_ON(!nommu_region_tree.rb_node);
613
614 validate_nommu_regions();
615 rb_erase(&region->vm_rb, &nommu_region_tree);
616 validate_nommu_regions();
617}
618
619/*
620 * free a contiguous series of pages
621 */
622static void free_page_series(unsigned long from, unsigned long to)
623{
624 for (; from < to; from += PAGE_SIZE) {
625 struct page *page = virt_to_page(from);
626
627 kdebug("- free %lx", from);
David Howells33e5d7692009-04-02 16:56:32 -0700628 atomic_long_dec(&mmap_pages_allocated);
David Howells8feae132009-01-08 12:04:47 +0000629 if (page_count(page) != 1)
David Howells33e5d7692009-04-02 16:56:32 -0700630 kdebug("free page %p: refcount not one: %d",
631 page, page_count(page));
David Howells8feae132009-01-08 12:04:47 +0000632 put_page(page);
633 }
634}
635
636/*
637 * release a reference to a region
David Howells33e5d7692009-04-02 16:56:32 -0700638 * - the caller must hold the region semaphore for writing, which this releases
Paul Mundtdd8632a2009-01-08 12:04:47 +0000639 * - the region may not have been added to the tree yet, in which case vm_top
David Howells8feae132009-01-08 12:04:47 +0000640 * will equal vm_start
641 */
642static void __put_nommu_region(struct vm_region *region)
643 __releases(nommu_region_sem)
644{
David Howells1e2ae592010-01-15 17:01:33 -0800645 kenter("%p{%d}", region, region->vm_usage);
David Howells8feae132009-01-08 12:04:47 +0000646
647 BUG_ON(!nommu_region_tree.rb_node);
648
David Howells1e2ae592010-01-15 17:01:33 -0800649 if (--region->vm_usage == 0) {
Paul Mundtdd8632a2009-01-08 12:04:47 +0000650 if (region->vm_top > region->vm_start)
David Howells8feae132009-01-08 12:04:47 +0000651 delete_nommu_region(region);
652 up_write(&nommu_region_sem);
653
654 if (region->vm_file)
655 fput(region->vm_file);
656
657 /* IO memory and memory shared directly out of the pagecache
658 * from ramfs/tmpfs mustn't be released here */
659 if (region->vm_flags & VM_MAPPED_COPY) {
660 kdebug("free series");
Paul Mundtdd8632a2009-01-08 12:04:47 +0000661 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +0000662 }
663 kmem_cache_free(vm_region_jar, region);
664 } else {
665 up_write(&nommu_region_sem);
666 }
667}
668
669/*
670 * release a reference to a region
671 */
672static void put_nommu_region(struct vm_region *region)
673{
674 down_write(&nommu_region_sem);
675 __put_nommu_region(region);
676}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677
David Howells30340972006-09-27 01:50:20 -0700678/*
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700679 * update protection on a vma
680 */
681static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
682{
683#ifdef CONFIG_MPU
684 struct mm_struct *mm = vma->vm_mm;
685 long start = vma->vm_start & PAGE_MASK;
686 while (start < vma->vm_end) {
687 protect_page(mm, start, flags);
688 start += PAGE_SIZE;
689 }
690 update_protections(mm);
691#endif
692}
693
694/*
David Howells30340972006-09-27 01:50:20 -0700695 * add a VMA into a process's mm_struct in the appropriate place in the list
David Howells8feae132009-01-08 12:04:47 +0000696 * and tree and add to the address space's page tree also if not an anonymous
697 * page
David Howells30340972006-09-27 01:50:20 -0700698 * - should be called with mm->mmap_sem held writelocked
699 */
David Howells8feae132009-01-08 12:04:47 +0000700static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
David Howells30340972006-09-27 01:50:20 -0700701{
Namhyung Kim6038def2011-05-24 17:11:22 -0700702 struct vm_area_struct *pvma, *prev;
David Howells8feae132009-01-08 12:04:47 +0000703 struct address_space *mapping;
Namhyung Kim6038def2011-05-24 17:11:22 -0700704 struct rb_node **p, *parent, *rb_prev;
David Howells30340972006-09-27 01:50:20 -0700705
David Howells8feae132009-01-08 12:04:47 +0000706 kenter(",%p", vma);
707
708 BUG_ON(!vma->vm_region);
709
710 mm->map_count++;
711 vma->vm_mm = mm;
712
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700713 protect_vma(vma, vma->vm_flags);
714
David Howells8feae132009-01-08 12:04:47 +0000715 /* add the VMA to the mapping */
716 if (vma->vm_file) {
717 mapping = vma->vm_file->f_mapping;
718
David Howells918e5562012-02-23 13:50:35 +0000719 mutex_lock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000720 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700721 vma_interval_tree_insert(vma, &mapping->i_mmap);
David Howells8feae132009-01-08 12:04:47 +0000722 flush_dcache_mmap_unlock(mapping);
David Howells918e5562012-02-23 13:50:35 +0000723 mutex_unlock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000724 }
725
726 /* add the VMA to the tree */
Namhyung Kim6038def2011-05-24 17:11:22 -0700727 parent = rb_prev = NULL;
David Howells8feae132009-01-08 12:04:47 +0000728 p = &mm->mm_rb.rb_node;
729 while (*p) {
730 parent = *p;
731 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
732
733 /* sort by: start addr, end addr, VMA struct addr in that order
734 * (the latter is necessary as we may get identical VMAs) */
735 if (vma->vm_start < pvma->vm_start)
736 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700737 else if (vma->vm_start > pvma->vm_start) {
738 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000739 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700740 } else if (vma->vm_end < pvma->vm_end)
David Howells8feae132009-01-08 12:04:47 +0000741 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700742 else if (vma->vm_end > pvma->vm_end) {
743 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000744 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700745 } else if (vma < pvma)
David Howells8feae132009-01-08 12:04:47 +0000746 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700747 else if (vma > pvma) {
748 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000749 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700750 } else
David Howells8feae132009-01-08 12:04:47 +0000751 BUG();
752 }
753
754 rb_link_node(&vma->vm_rb, parent, p);
755 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
756
757 /* add VMA to the VMA list also */
Namhyung Kim6038def2011-05-24 17:11:22 -0700758 prev = NULL;
759 if (rb_prev)
760 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
David Howells30340972006-09-27 01:50:20 -0700761
Namhyung Kim6038def2011-05-24 17:11:22 -0700762 __vma_link_list(mm, vma, prev, parent);
David Howells8feae132009-01-08 12:04:47 +0000763}
764
765/*
766 * delete a VMA from its owning mm_struct and address space
767 */
768static void delete_vma_from_mm(struct vm_area_struct *vma)
769{
David Howells8feae132009-01-08 12:04:47 +0000770 struct address_space *mapping;
771 struct mm_struct *mm = vma->vm_mm;
772
773 kenter("%p", vma);
774
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700775 protect_vma(vma, 0);
776
David Howells8feae132009-01-08 12:04:47 +0000777 mm->map_count--;
778 if (mm->mmap_cache == vma)
779 mm->mmap_cache = NULL;
780
781 /* remove the VMA from the mapping */
782 if (vma->vm_file) {
783 mapping = vma->vm_file->f_mapping;
784
David Howells918e5562012-02-23 13:50:35 +0000785 mutex_lock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000786 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700787 vma_interval_tree_remove(vma, &mapping->i_mmap);
David Howells8feae132009-01-08 12:04:47 +0000788 flush_dcache_mmap_unlock(mapping);
David Howells918e5562012-02-23 13:50:35 +0000789 mutex_unlock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000790 }
791
792 /* remove from the MM's tree and list */
793 rb_erase(&vma->vm_rb, &mm->mm_rb);
Namhyung Kimb951bf22011-05-24 17:11:23 -0700794
795 if (vma->vm_prev)
796 vma->vm_prev->vm_next = vma->vm_next;
797 else
798 mm->mmap = vma->vm_next;
799
800 if (vma->vm_next)
801 vma->vm_next->vm_prev = vma->vm_prev;
David Howells8feae132009-01-08 12:04:47 +0000802}
803
804/*
805 * destroy a VMA record
806 */
807static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
808{
809 kenter("%p", vma);
810 if (vma->vm_ops && vma->vm_ops->close)
811 vma->vm_ops->close(vma);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -0700812 if (vma->vm_file)
David Howells8feae132009-01-08 12:04:47 +0000813 fput(vma->vm_file);
David Howells8feae132009-01-08 12:04:47 +0000814 put_nommu_region(vma->vm_region);
815 kmem_cache_free(vm_area_cachep, vma);
David Howells30340972006-09-27 01:50:20 -0700816}
817
818/*
819 * look up the first VMA in which addr resides, NULL if none
820 * - should be called with mm->mmap_sem at least held readlocked
821 */
822struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
823{
David Howells8feae132009-01-08 12:04:47 +0000824 struct vm_area_struct *vma;
David Howells30340972006-09-27 01:50:20 -0700825
David Howells8feae132009-01-08 12:04:47 +0000826 /* check the cache first */
Jan Stancekb6a9b7f2013-04-04 11:35:10 -0700827 vma = ACCESS_ONCE(mm->mmap_cache);
David Howells8feae132009-01-08 12:04:47 +0000828 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
829 return vma;
830
Namhyung Kime922c4c2011-05-24 17:11:24 -0700831 /* trawl the list (there may be multiple mappings in which addr
David Howells8feae132009-01-08 12:04:47 +0000832 * resides) */
Namhyung Kime922c4c2011-05-24 17:11:24 -0700833 for (vma = mm->mmap; vma; vma = vma->vm_next) {
David Howells8feae132009-01-08 12:04:47 +0000834 if (vma->vm_start > addr)
835 return NULL;
836 if (vma->vm_end > addr) {
837 mm->mmap_cache = vma;
838 return vma;
839 }
David Howells30340972006-09-27 01:50:20 -0700840 }
841
David Howells30340972006-09-27 01:50:20 -0700842 return NULL;
843}
844EXPORT_SYMBOL(find_vma);
845
846/*
David Howells930e6522006-09-27 01:50:22 -0700847 * find a VMA
848 * - we don't extend stack VMAs under NOMMU conditions
849 */
850struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
851{
David Howells7561e8c2010-03-25 16:48:38 +0000852 return find_vma(mm, addr);
David Howells930e6522006-09-27 01:50:22 -0700853}
854
David Howells8feae132009-01-08 12:04:47 +0000855/*
856 * expand a stack to a given address
857 * - not supported under NOMMU conditions
858 */
Greg Ungerer57c8f632007-07-15 23:38:28 -0700859int expand_stack(struct vm_area_struct *vma, unsigned long address)
860{
861 return -ENOMEM;
862}
863
David Howells930e6522006-09-27 01:50:22 -0700864/*
David Howells6fa5f802006-09-27 01:50:21 -0700865 * look up the first VMA exactly that exactly matches addr
866 * - should be called with mm->mmap_sem at least held readlocked
867 */
David Howells8feae132009-01-08 12:04:47 +0000868static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
869 unsigned long addr,
870 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871{
872 struct vm_area_struct *vma;
David Howells8feae132009-01-08 12:04:47 +0000873 unsigned long end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874
David Howells8feae132009-01-08 12:04:47 +0000875 /* check the cache first */
876 vma = mm->mmap_cache;
877 if (vma && vma->vm_start == addr && vma->vm_end == end)
878 return vma;
879
Namhyung Kime922c4c2011-05-24 17:11:24 -0700880 /* trawl the list (there may be multiple mappings in which addr
David Howells8feae132009-01-08 12:04:47 +0000881 * resides) */
Namhyung Kime922c4c2011-05-24 17:11:24 -0700882 for (vma = mm->mmap; vma; vma = vma->vm_next) {
David Howells8feae132009-01-08 12:04:47 +0000883 if (vma->vm_start < addr)
884 continue;
885 if (vma->vm_start > addr)
886 return NULL;
887 if (vma->vm_end == end) {
888 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889 return vma;
David Howells8feae132009-01-08 12:04:47 +0000890 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 }
892
893 return NULL;
894}
895
David Howells30340972006-09-27 01:50:20 -0700896/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 * determine whether a mapping should be permitted and, if so, what sort of
898 * mapping we're capable of supporting
899 */
900static int validate_mmap_request(struct file *file,
901 unsigned long addr,
902 unsigned long len,
903 unsigned long prot,
904 unsigned long flags,
905 unsigned long pgoff,
906 unsigned long *_capabilities)
907{
David Howells8feae132009-01-08 12:04:47 +0000908 unsigned long capabilities, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700909 int ret;
910
911 /* do the simple checks first */
David Howells06aab5a2009-09-24 12:33:48 +0100912 if (flags & MAP_FIXED) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 printk(KERN_DEBUG
914 "%d: Can't do fixed-address/overlay mmap of RAM\n",
915 current->pid);
916 return -EINVAL;
917 }
918
919 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
920 (flags & MAP_TYPE) != MAP_SHARED)
921 return -EINVAL;
922
Mike Frysingerf81cff02006-12-06 12:02:59 +1000923 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 return -EINVAL;
925
Mike Frysingerf81cff02006-12-06 12:02:59 +1000926 /* Careful about overflows.. */
David Howells8feae132009-01-08 12:04:47 +0000927 rlen = PAGE_ALIGN(len);
928 if (!rlen || rlen > TASK_SIZE)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000929 return -ENOMEM;
930
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 /* offset overflow? */
David Howells8feae132009-01-08 12:04:47 +0000932 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000933 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934
935 if (file) {
936 /* validate file mapping requests */
937 struct address_space *mapping;
938
939 /* files must support mmap */
Al Viro72c2d532013-09-22 16:27:52 -0400940 if (!file->f_op->mmap)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 return -ENODEV;
942
943 /* work out if what we've got could possibly be shared
944 * - we support chardevs that provide their own "memory"
945 * - we support files/blockdevs that are memory backed
946 */
947 mapping = file->f_mapping;
948 if (!mapping)
Al Viro496ad9a2013-01-23 17:07:38 -0500949 mapping = file_inode(file)->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950
951 capabilities = 0;
952 if (mapping && mapping->backing_dev_info)
953 capabilities = mapping->backing_dev_info->capabilities;
954
955 if (!capabilities) {
956 /* no explicit capabilities set, so assume some
957 * defaults */
Al Viro496ad9a2013-01-23 17:07:38 -0500958 switch (file_inode(file)->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 case S_IFREG:
960 case S_IFBLK:
961 capabilities = BDI_CAP_MAP_COPY;
962 break;
963
964 case S_IFCHR:
965 capabilities =
966 BDI_CAP_MAP_DIRECT |
967 BDI_CAP_READ_MAP |
968 BDI_CAP_WRITE_MAP;
969 break;
970
971 default:
972 return -EINVAL;
973 }
974 }
975
976 /* eliminate any capabilities that we can't support on this
977 * device */
978 if (!file->f_op->get_unmapped_area)
979 capabilities &= ~BDI_CAP_MAP_DIRECT;
980 if (!file->f_op->read)
981 capabilities &= ~BDI_CAP_MAP_COPY;
982
Graff Yang28d7a6a2009-08-18 14:11:17 -0700983 /* The file shall have been opened with read permission. */
984 if (!(file->f_mode & FMODE_READ))
985 return -EACCES;
986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 if (flags & MAP_SHARED) {
988 /* do checks for writing, appending and locking */
989 if ((prot & PROT_WRITE) &&
990 !(file->f_mode & FMODE_WRITE))
991 return -EACCES;
992
Al Viro496ad9a2013-01-23 17:07:38 -0500993 if (IS_APPEND(file_inode(file)) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 (file->f_mode & FMODE_WRITE))
995 return -EACCES;
996
Al Viro496ad9a2013-01-23 17:07:38 -0500997 if (locks_verify_locked(file_inode(file)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 return -EAGAIN;
999
1000 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1001 return -ENODEV;
1002
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 /* we mustn't privatise shared mappings */
1004 capabilities &= ~BDI_CAP_MAP_COPY;
1005 }
1006 else {
1007 /* we're going to read the file into private memory we
1008 * allocate */
1009 if (!(capabilities & BDI_CAP_MAP_COPY))
1010 return -ENODEV;
1011
1012 /* we don't permit a private writable mapping to be
1013 * shared with the backing device */
1014 if (prot & PROT_WRITE)
1015 capabilities &= ~BDI_CAP_MAP_DIRECT;
1016 }
1017
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001018 if (capabilities & BDI_CAP_MAP_DIRECT) {
1019 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
1020 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
1021 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
1022 ) {
1023 capabilities &= ~BDI_CAP_MAP_DIRECT;
1024 if (flags & MAP_SHARED) {
1025 printk(KERN_WARNING
1026 "MAP_SHARED not completely supported on !MMU\n");
1027 return -EINVAL;
1028 }
1029 }
1030 }
1031
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 /* handle executable mappings and implied executable
1033 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -08001034 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 if (prot & PROT_EXEC)
1036 return -EPERM;
1037 }
1038 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
1039 /* handle implication of PROT_EXEC by PROT_READ */
1040 if (current->personality & READ_IMPLIES_EXEC) {
1041 if (capabilities & BDI_CAP_EXEC_MAP)
1042 prot |= PROT_EXEC;
1043 }
1044 }
1045 else if ((prot & PROT_READ) &&
1046 (prot & PROT_EXEC) &&
1047 !(capabilities & BDI_CAP_EXEC_MAP)
1048 ) {
1049 /* backing file is not executable, try to copy */
1050 capabilities &= ~BDI_CAP_MAP_DIRECT;
1051 }
1052 }
1053 else {
1054 /* anonymous mappings are always memory backed and can be
1055 * privately mapped
1056 */
1057 capabilities = BDI_CAP_MAP_COPY;
1058
1059 /* handle PROT_EXEC implication by PROT_READ */
1060 if ((prot & PROT_READ) &&
1061 (current->personality & READ_IMPLIES_EXEC))
1062 prot |= PROT_EXEC;
1063 }
1064
1065 /* allow the security API to have its say */
Al Viroe5467852012-05-30 13:30:51 -04001066 ret = security_mmap_addr(addr);
1067 if (ret < 0)
1068 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069
1070 /* looks okay */
1071 *_capabilities = capabilities;
1072 return 0;
1073}
1074
1075/*
1076 * we've determined that we can make the mapping, now translate what we
1077 * now know into VMA flags
1078 */
1079static unsigned long determine_vm_flags(struct file *file,
1080 unsigned long prot,
1081 unsigned long flags,
1082 unsigned long capabilities)
1083{
1084 unsigned long vm_flags;
1085
1086 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087 /* vm_flags |= mm->def_flags; */
1088
1089 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1090 /* attempt to share read-only copies of mapped file chunks */
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001091 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 if (file && !(prot & PROT_WRITE))
1093 vm_flags |= VM_MAYSHARE;
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001094 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 /* overlay a shareable mapping on the backing device or inode
1096 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1097 * romfs/cramfs */
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001098 vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099 if (flags & MAP_SHARED)
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001100 vm_flags |= VM_SHARED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001101 }
1102
1103 /* refuse to let anyone share private mappings with this process if
1104 * it's being traced - otherwise breakpoints set in it may interfere
1105 * with another untraced process
1106 */
Tejun Heoa288eec2011-06-17 16:50:37 +02001107 if ((flags & MAP_PRIVATE) && current->ptrace)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 vm_flags &= ~VM_MAYSHARE;
1109
1110 return vm_flags;
1111}
1112
1113/*
David Howells8feae132009-01-08 12:04:47 +00001114 * set up a shared mapping on a file (the driver or filesystem provides and
1115 * pins the storage)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 */
David Howells8feae132009-01-08 12:04:47 +00001117static int do_mmap_shared_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118{
1119 int ret;
1120
1121 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001122 if (ret == 0) {
1123 vma->vm_region->vm_top = vma->vm_region->vm_end;
David Howells645d83c2009-09-24 15:13:10 +01001124 return 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001125 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001126 if (ret != -ENOSYS)
1127 return ret;
1128
David Howells3fa30462010-03-23 13:35:21 -07001129 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1130 * opposed to tried but failed) so we can only give a suitable error as
1131 * it's not possible to make a private copy if MAP_SHARED was given */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132 return -ENODEV;
1133}
1134
1135/*
1136 * set up a private mapping or an anonymous shared mapping
1137 */
David Howells8feae132009-01-08 12:04:47 +00001138static int do_mmap_private(struct vm_area_struct *vma,
1139 struct vm_region *region,
David Howells645d83c2009-09-24 15:13:10 +01001140 unsigned long len,
1141 unsigned long capabilities)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142{
David Howells8feae132009-01-08 12:04:47 +00001143 struct page *pages;
Bob Liuf67d9b12011-05-24 17:12:56 -07001144 unsigned long total, point, n;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 void *base;
David Howells8feae132009-01-08 12:04:47 +00001146 int ret, order;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147
1148 /* invoke the file's mapping function so that it can keep track of
1149 * shared mappings on devices or memory
1150 * - VM_MAYSHARE will be set if it may attempt to share
1151 */
David Howells645d83c2009-09-24 15:13:10 +01001152 if (capabilities & BDI_CAP_MAP_DIRECT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001154 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 /* shouldn't return success if we're not sharing */
Paul Mundtdd8632a2009-01-08 12:04:47 +00001156 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1157 vma->vm_region->vm_top = vma->vm_region->vm_end;
David Howells645d83c2009-09-24 15:13:10 +01001158 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 }
Paul Mundtdd8632a2009-01-08 12:04:47 +00001160 if (ret != -ENOSYS)
1161 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
1163 /* getting an ENOSYS error indicates that direct mmap isn't
1164 * possible (as opposed to tried but failed) so we'll try to
1165 * make a private copy of the data and map that instead */
1166 }
1167
David Howells8feae132009-01-08 12:04:47 +00001168
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 /* allocate some memory to hold the mapping
1170 * - note that this may not return a page-aligned address if the object
1171 * we're allocating is smaller than a page
1172 */
Bob Liuf67d9b12011-05-24 17:12:56 -07001173 order = get_order(len);
David Howells8feae132009-01-08 12:04:47 +00001174 kdebug("alloc order %d for %lx", order, len);
1175
1176 pages = alloc_pages(GFP_KERNEL, order);
1177 if (!pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 goto enomem;
1179
David Howells8feae132009-01-08 12:04:47 +00001180 total = 1 << order;
David Howells33e5d7692009-04-02 16:56:32 -07001181 atomic_long_add(total, &mmap_pages_allocated);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182
Bob Liuf67d9b12011-05-24 17:12:56 -07001183 point = len >> PAGE_SHIFT;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001184
1185 /* we allocated a power-of-2 sized page set, so we may want to trim off
1186 * the excess */
1187 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1188 while (total > point) {
1189 order = ilog2(total - point);
1190 n = 1 << order;
1191 kdebug("shave %lu/%lu @%lu", n, total - point, total);
David Howells33e5d7692009-04-02 16:56:32 -07001192 atomic_long_sub(n, &mmap_pages_allocated);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001193 total -= n;
1194 set_page_refcounted(pages + total);
1195 __free_pages(pages + total, order);
1196 }
David Howells8feae132009-01-08 12:04:47 +00001197 }
1198
David Howells8feae132009-01-08 12:04:47 +00001199 for (point = 1; point < total; point++)
1200 set_page_refcounted(&pages[point]);
1201
1202 base = page_address(pages);
1203 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1204 region->vm_start = (unsigned long) base;
Bob Liuf67d9b12011-05-24 17:12:56 -07001205 region->vm_end = region->vm_start + len;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001206 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
David Howells8feae132009-01-08 12:04:47 +00001207
1208 vma->vm_start = region->vm_start;
1209 vma->vm_end = region->vm_start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210
1211 if (vma->vm_file) {
1212 /* read the contents of a file into the copy */
1213 mm_segment_t old_fs;
1214 loff_t fpos;
1215
1216 fpos = vma->vm_pgoff;
1217 fpos <<= PAGE_SHIFT;
1218
1219 old_fs = get_fs();
1220 set_fs(KERNEL_DS);
Bob Liuf67d9b12011-05-24 17:12:56 -07001221 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 set_fs(old_fs);
1223
1224 if (ret < 0)
1225 goto error_free;
1226
1227 /* clear the last little bit */
Bob Liuf67d9b12011-05-24 17:12:56 -07001228 if (ret < len)
1229 memset(base + ret, 0, len - ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 }
1232
1233 return 0;
1234
1235error_free:
Namhyung Kim7223bb42011-05-24 17:11:26 -07001236 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +00001237 region->vm_start = vma->vm_start = 0;
1238 region->vm_end = vma->vm_end = 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001239 region->vm_top = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 return ret;
1241
1242enomem:
Greg Ungerer05ae6fa2009-01-13 17:30:22 +10001243 printk("Allocation of length %lu from process %d (%s) failed\n",
1244 len, current->pid, current->comm);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001245 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 return -ENOMEM;
1247}
1248
1249/*
1250 * handle mapping creation for uClinux
1251 */
Al Viroe3fc6292012-05-30 20:08:42 -04001252unsigned long do_mmap_pgoff(struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 unsigned long addr,
1254 unsigned long len,
1255 unsigned long prot,
1256 unsigned long flags,
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001257 unsigned long pgoff,
Michel Lespinasse41badc12013-02-22 16:32:47 -08001258 unsigned long *populate)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259{
David Howells8feae132009-01-08 12:04:47 +00001260 struct vm_area_struct *vma;
1261 struct vm_region *region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 struct rb_node *rb;
David Howells8feae132009-01-08 12:04:47 +00001263 unsigned long capabilities, vm_flags, result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 int ret;
1265
David Howells8feae132009-01-08 12:04:47 +00001266 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1267
Michel Lespinasse41badc12013-02-22 16:32:47 -08001268 *populate = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001269
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 /* decide whether we should attempt the mapping, and if so what sort of
1271 * mapping */
1272 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1273 &capabilities);
David Howells8feae132009-01-08 12:04:47 +00001274 if (ret < 0) {
1275 kleave(" = %d [val]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 return ret;
David Howells8feae132009-01-08 12:04:47 +00001277 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278
David Howells06aab5a2009-09-24 12:33:48 +01001279 /* we ignore the address hint */
1280 addr = 0;
Bob Liuf67d9b12011-05-24 17:12:56 -07001281 len = PAGE_ALIGN(len);
David Howells06aab5a2009-09-24 12:33:48 +01001282
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 /* we've determined that we can make the mapping, now translate what we
1284 * now know into VMA flags */
1285 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1286
David Howells8feae132009-01-08 12:04:47 +00001287 /* we're going to need to record the mapping */
1288 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1289 if (!region)
1290 goto error_getting_region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291
David Howells8feae132009-01-08 12:04:47 +00001292 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1293 if (!vma)
1294 goto error_getting_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001295
David Howells1e2ae592010-01-15 17:01:33 -08001296 region->vm_usage = 1;
David Howells8feae132009-01-08 12:04:47 +00001297 region->vm_flags = vm_flags;
1298 region->vm_pgoff = pgoff;
1299
Rik van Riel5beb4932010-03-05 13:42:07 -08001300 INIT_LIST_HEAD(&vma->anon_vma_chain);
David Howells8feae132009-01-08 12:04:47 +00001301 vma->vm_flags = vm_flags;
1302 vma->vm_pgoff = pgoff;
1303
1304 if (file) {
Al Virocb0942b2012-08-27 14:48:26 -04001305 region->vm_file = get_file(file);
1306 vma->vm_file = get_file(file);
David Howells8feae132009-01-08 12:04:47 +00001307 }
1308
1309 down_write(&nommu_region_sem);
1310
1311 /* if we want to share, we need to check for regions created by other
Linus Torvalds1da177e2005-04-16 15:20:36 -07001312 * mmap() calls that overlap with our proposed mapping
David Howells8feae132009-01-08 12:04:47 +00001313 * - we can only share with a superset match on most regular files
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 * - shared mappings on character devices and memory backed files are
1315 * permitted to overlap inexactly as far as we are concerned for in
1316 * these cases, sharing is handled in the driver or filesystem rather
1317 * than here
1318 */
1319 if (vm_flags & VM_MAYSHARE) {
David Howells8feae132009-01-08 12:04:47 +00001320 struct vm_region *pregion;
1321 unsigned long pglen, rpglen, pgend, rpgend, start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001322
David Howells8feae132009-01-08 12:04:47 +00001323 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1324 pgend = pgoff + pglen;
David Howells165b2392007-03-22 00:11:24 -08001325
David Howells8feae132009-01-08 12:04:47 +00001326 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1327 pregion = rb_entry(rb, struct vm_region, vm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328
David Howells8feae132009-01-08 12:04:47 +00001329 if (!(pregion->vm_flags & VM_MAYSHARE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330 continue;
1331
1332 /* search for overlapping mappings on the same file */
Al Viro496ad9a2013-01-23 17:07:38 -05001333 if (file_inode(pregion->vm_file) !=
1334 file_inode(file))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 continue;
1336
David Howells8feae132009-01-08 12:04:47 +00001337 if (pregion->vm_pgoff >= pgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338 continue;
1339
David Howells8feae132009-01-08 12:04:47 +00001340 rpglen = pregion->vm_end - pregion->vm_start;
1341 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1342 rpgend = pregion->vm_pgoff + rpglen;
1343 if (pgoff >= rpgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 continue;
1345
David Howells8feae132009-01-08 12:04:47 +00001346 /* handle inexactly overlapping matches between
1347 * mappings */
1348 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1349 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1350 /* new mapping is not a subset of the region */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1352 goto sharing_violation;
1353 continue;
1354 }
1355
David Howells8feae132009-01-08 12:04:47 +00001356 /* we've found a region we can share */
David Howells1e2ae592010-01-15 17:01:33 -08001357 pregion->vm_usage++;
David Howells8feae132009-01-08 12:04:47 +00001358 vma->vm_region = pregion;
1359 start = pregion->vm_start;
1360 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1361 vma->vm_start = start;
1362 vma->vm_end = start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001363
David Howells8feae132009-01-08 12:04:47 +00001364 if (pregion->vm_flags & VM_MAPPED_COPY) {
1365 kdebug("share copy");
1366 vma->vm_flags |= VM_MAPPED_COPY;
1367 } else {
1368 kdebug("share mmap");
1369 ret = do_mmap_shared_file(vma);
1370 if (ret < 0) {
1371 vma->vm_region = NULL;
1372 vma->vm_start = 0;
1373 vma->vm_end = 0;
David Howells1e2ae592010-01-15 17:01:33 -08001374 pregion->vm_usage--;
David Howells8feae132009-01-08 12:04:47 +00001375 pregion = NULL;
1376 goto error_just_free;
1377 }
1378 }
1379 fput(region->vm_file);
1380 kmem_cache_free(vm_region_jar, region);
1381 region = pregion;
1382 result = start;
1383 goto share;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001384 }
1385
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386 /* obtain the address at which to make a shared mapping
1387 * - this is the hook for quasi-memory character devices to
1388 * tell us the location of a shared mapping
1389 */
David Howells645d83c2009-09-24 15:13:10 +01001390 if (capabilities & BDI_CAP_MAP_DIRECT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 addr = file->f_op->get_unmapped_area(file, addr, len,
1392 pgoff, flags);
Namhyung Kimbb005a52011-05-24 17:11:27 -07001393 if (IS_ERR_VALUE(addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394 ret = addr;
Namhyung Kimbb005a52011-05-24 17:11:27 -07001395 if (ret != -ENOSYS)
David Howells8feae132009-01-08 12:04:47 +00001396 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397
1398 /* the driver refused to tell us where to site
1399 * the mapping so we'll have to attempt to copy
1400 * it */
Namhyung Kimbb005a52011-05-24 17:11:27 -07001401 ret = -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001402 if (!(capabilities & BDI_CAP_MAP_COPY))
David Howells8feae132009-01-08 12:04:47 +00001403 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404
1405 capabilities &= ~BDI_CAP_MAP_DIRECT;
David Howells8feae132009-01-08 12:04:47 +00001406 } else {
1407 vma->vm_start = region->vm_start = addr;
1408 vma->vm_end = region->vm_end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001409 }
1410 }
1411 }
1412
David Howells8feae132009-01-08 12:04:47 +00001413 vma->vm_region = region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001414
David Howells645d83c2009-09-24 15:13:10 +01001415 /* set up the mapping
1416 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1417 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001418 if (file && vma->vm_flags & VM_SHARED)
David Howells8feae132009-01-08 12:04:47 +00001419 ret = do_mmap_shared_file(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001420 else
David Howells645d83c2009-09-24 15:13:10 +01001421 ret = do_mmap_private(vma, region, len, capabilities);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422 if (ret < 0)
David Howells645d83c2009-09-24 15:13:10 +01001423 goto error_just_free;
1424 add_nommu_region(region);
David Howells8feae132009-01-08 12:04:47 +00001425
Jie Zhangea637632009-12-14 18:00:02 -08001426 /* clear anonymous mappings that don't ask for uninitialized data */
1427 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1428 memset((void *)region->vm_start, 0,
1429 region->vm_end - region->vm_start);
1430
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 /* okay... we have a mapping; now we have to register it */
David Howells8feae132009-01-08 12:04:47 +00001432 result = vma->vm_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001433
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434 current->mm->total_vm += len >> PAGE_SHIFT;
1435
David Howells8feae132009-01-08 12:04:47 +00001436share:
1437 add_vma_to_mm(current->mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438
Mike Frysingercfe79c02010-01-06 17:23:23 +00001439 /* we flush the region from the icache only when the first executable
1440 * mapping of it is made */
1441 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1442 flush_icache_range(region->vm_start, region->vm_end);
1443 region->vm_icache_flushed = true;
1444 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445
Mike Frysingercfe79c02010-01-06 17:23:23 +00001446 up_write(&nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447
David Howells8feae132009-01-08 12:04:47 +00001448 kleave(" = %lx", result);
1449 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450
David Howells8feae132009-01-08 12:04:47 +00001451error_just_free:
1452 up_write(&nommu_region_sem);
1453error:
David Howells89a86402009-10-30 13:13:26 +00001454 if (region->vm_file)
1455 fput(region->vm_file);
David Howells8feae132009-01-08 12:04:47 +00001456 kmem_cache_free(vm_region_jar, region);
David Howells89a86402009-10-30 13:13:26 +00001457 if (vma->vm_file)
1458 fput(vma->vm_file);
David Howells8feae132009-01-08 12:04:47 +00001459 kmem_cache_free(vm_area_cachep, vma);
1460 kleave(" = %d", ret);
1461 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
David Howells8feae132009-01-08 12:04:47 +00001463sharing_violation:
1464 up_write(&nommu_region_sem);
1465 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1466 ret = -EINVAL;
1467 goto error;
1468
1469error_getting_vma:
1470 kmem_cache_free(vm_region_jar, region);
1471 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1472 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001473 len, current->pid);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001474 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 return -ENOMEM;
1476
David Howells8feae132009-01-08 12:04:47 +00001477error_getting_region:
1478 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1479 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 len, current->pid);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001481 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 return -ENOMEM;
1483}
Linus Torvalds6be5ceb2012-04-20 17:13:58 -07001484
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001485SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1486 unsigned long, prot, unsigned long, flags,
1487 unsigned long, fd, unsigned long, pgoff)
1488{
1489 struct file *file = NULL;
1490 unsigned long retval = -EBADF;
1491
Al Viro120a7952010-10-30 02:54:44 -04001492 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001493 if (!(flags & MAP_ANONYMOUS)) {
1494 file = fget(fd);
1495 if (!file)
1496 goto out;
1497 }
1498
1499 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1500
Greg Ungererad1ed292012-06-04 14:29:59 +10001501 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001502
1503 if (file)
1504 fput(file);
1505out:
1506 return retval;
1507}
1508
Christoph Hellwiga4679372010-03-10 15:21:15 -08001509#ifdef __ARCH_WANT_SYS_OLD_MMAP
1510struct mmap_arg_struct {
1511 unsigned long addr;
1512 unsigned long len;
1513 unsigned long prot;
1514 unsigned long flags;
1515 unsigned long fd;
1516 unsigned long offset;
1517};
1518
1519SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1520{
1521 struct mmap_arg_struct a;
1522
1523 if (copy_from_user(&a, arg, sizeof(a)))
1524 return -EFAULT;
1525 if (a.offset & ~PAGE_MASK)
1526 return -EINVAL;
1527
1528 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1529 a.offset >> PAGE_SHIFT);
1530}
1531#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1532
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533/*
David Howells8feae132009-01-08 12:04:47 +00001534 * split a vma into two pieces at address 'addr', a new vma is allocated either
1535 * for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 */
David Howells8feae132009-01-08 12:04:47 +00001537int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1538 unsigned long addr, int new_below)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001539{
David Howells8feae132009-01-08 12:04:47 +00001540 struct vm_area_struct *new;
1541 struct vm_region *region;
1542 unsigned long npages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543
David Howells8feae132009-01-08 12:04:47 +00001544 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545
David Howells779c1022010-01-15 17:01:34 -08001546 /* we're only permitted to split anonymous regions (these should have
1547 * only a single usage on the region) */
1548 if (vma->vm_file)
David Howells8feae132009-01-08 12:04:47 +00001549 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550
David Howells8feae132009-01-08 12:04:47 +00001551 if (mm->map_count >= sysctl_max_map_count)
1552 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001553
David Howells8feae132009-01-08 12:04:47 +00001554 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1555 if (!region)
1556 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557
David Howells8feae132009-01-08 12:04:47 +00001558 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1559 if (!new) {
1560 kmem_cache_free(vm_region_jar, region);
1561 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 }
David Howells8feae132009-01-08 12:04:47 +00001563
1564 /* most fields are the same, copy all, and then fixup */
1565 *new = *vma;
1566 *region = *vma->vm_region;
1567 new->vm_region = region;
1568
1569 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1570
1571 if (new_below) {
Paul Mundtdd8632a2009-01-08 12:04:47 +00001572 region->vm_top = region->vm_end = new->vm_end = addr;
David Howells8feae132009-01-08 12:04:47 +00001573 } else {
1574 region->vm_start = new->vm_start = addr;
1575 region->vm_pgoff = new->vm_pgoff += npages;
1576 }
1577
1578 if (new->vm_ops && new->vm_ops->open)
1579 new->vm_ops->open(new);
1580
1581 delete_vma_from_mm(vma);
1582 down_write(&nommu_region_sem);
1583 delete_nommu_region(vma->vm_region);
1584 if (new_below) {
1585 vma->vm_region->vm_start = vma->vm_start = addr;
1586 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1587 } else {
1588 vma->vm_region->vm_end = vma->vm_end = addr;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001589 vma->vm_region->vm_top = addr;
David Howells8feae132009-01-08 12:04:47 +00001590 }
1591 add_nommu_region(vma->vm_region);
1592 add_nommu_region(new->vm_region);
1593 up_write(&nommu_region_sem);
1594 add_vma_to_mm(mm, vma);
1595 add_vma_to_mm(mm, new);
1596 return 0;
1597}
1598
1599/*
1600 * shrink a VMA by removing the specified chunk from either the beginning or
1601 * the end
1602 */
1603static int shrink_vma(struct mm_struct *mm,
1604 struct vm_area_struct *vma,
1605 unsigned long from, unsigned long to)
1606{
1607 struct vm_region *region;
1608
1609 kenter("");
1610
1611 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1612 * and list */
1613 delete_vma_from_mm(vma);
1614 if (from > vma->vm_start)
1615 vma->vm_end = from;
1616 else
1617 vma->vm_start = to;
1618 add_vma_to_mm(mm, vma);
1619
1620 /* cut the backing region down to size */
1621 region = vma->vm_region;
David Howells1e2ae592010-01-15 17:01:33 -08001622 BUG_ON(region->vm_usage != 1);
David Howells8feae132009-01-08 12:04:47 +00001623
1624 down_write(&nommu_region_sem);
1625 delete_nommu_region(region);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001626 if (from > region->vm_start) {
1627 to = region->vm_top;
1628 region->vm_top = region->vm_end = from;
1629 } else {
David Howells8feae132009-01-08 12:04:47 +00001630 region->vm_start = to;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001631 }
David Howells8feae132009-01-08 12:04:47 +00001632 add_nommu_region(region);
1633 up_write(&nommu_region_sem);
1634
1635 free_page_series(from, to);
1636 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001637}
1638
David Howells30340972006-09-27 01:50:20 -07001639/*
1640 * release a mapping
David Howells8feae132009-01-08 12:04:47 +00001641 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1642 * VMA, though it need not cover the whole VMA
David Howells30340972006-09-27 01:50:20 -07001643 */
David Howells8feae132009-01-08 12:04:47 +00001644int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645{
David Howells8feae132009-01-08 12:04:47 +00001646 struct vm_area_struct *vma;
Bob Liuf67d9b12011-05-24 17:12:56 -07001647 unsigned long end;
David Howells8feae132009-01-08 12:04:47 +00001648 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649
David Howells8feae132009-01-08 12:04:47 +00001650 kenter(",%lx,%zx", start, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001651
Bob Liuf67d9b12011-05-24 17:12:56 -07001652 len = PAGE_ALIGN(len);
David Howells8feae132009-01-08 12:04:47 +00001653 if (len == 0)
1654 return -EINVAL;
1655
Bob Liuf67d9b12011-05-24 17:12:56 -07001656 end = start + len;
1657
David Howells8feae132009-01-08 12:04:47 +00001658 /* find the first potentially overlapping VMA */
1659 vma = find_vma(mm, start);
1660 if (!vma) {
David Howells33e5d7692009-04-02 16:56:32 -07001661 static int limit = 0;
1662 if (limit < 5) {
1663 printk(KERN_WARNING
1664 "munmap of memory not mmapped by process %d"
1665 " (%s): 0x%lx-0x%lx\n",
1666 current->pid, current->comm,
1667 start, start + len - 1);
1668 limit++;
1669 }
David Howells8feae132009-01-08 12:04:47 +00001670 return -EINVAL;
David Howells30340972006-09-27 01:50:20 -07001671 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672
David Howells8feae132009-01-08 12:04:47 +00001673 /* we're allowed to split an anonymous VMA but not a file-backed one */
1674 if (vma->vm_file) {
1675 do {
1676 if (start > vma->vm_start) {
1677 kleave(" = -EINVAL [miss]");
1678 return -EINVAL;
1679 }
1680 if (end == vma->vm_end)
1681 goto erase_whole_vma;
Namhyung Kimd75a3102011-05-24 17:11:25 -07001682 vma = vma->vm_next;
1683 } while (vma);
David Howells8feae132009-01-08 12:04:47 +00001684 kleave(" = -EINVAL [split file]");
1685 return -EINVAL;
1686 } else {
1687 /* the chunk must be a subset of the VMA found */
1688 if (start == vma->vm_start && end == vma->vm_end)
1689 goto erase_whole_vma;
1690 if (start < vma->vm_start || end > vma->vm_end) {
1691 kleave(" = -EINVAL [superset]");
1692 return -EINVAL;
1693 }
1694 if (start & ~PAGE_MASK) {
1695 kleave(" = -EINVAL [unaligned start]");
1696 return -EINVAL;
1697 }
1698 if (end != vma->vm_end && end & ~PAGE_MASK) {
1699 kleave(" = -EINVAL [unaligned split]");
1700 return -EINVAL;
1701 }
1702 if (start != vma->vm_start && end != vma->vm_end) {
1703 ret = split_vma(mm, vma, start, 1);
1704 if (ret < 0) {
1705 kleave(" = %d [split]", ret);
1706 return ret;
1707 }
1708 }
1709 return shrink_vma(mm, vma, start, end);
1710 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001711
David Howells8feae132009-01-08 12:04:47 +00001712erase_whole_vma:
1713 delete_vma_from_mm(vma);
1714 delete_vma(mm, vma);
1715 kleave(" = 0");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716 return 0;
1717}
Paul Mundtb5073172007-07-21 04:37:25 -07001718EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719
Al Virobfce2812012-04-20 21:57:04 -04001720int vm_munmap(unsigned long addr, size_t len)
David Howells30340972006-09-27 01:50:20 -07001721{
Al Virobfce2812012-04-20 21:57:04 -04001722 struct mm_struct *mm = current->mm;
David Howells30340972006-09-27 01:50:20 -07001723 int ret;
David Howells30340972006-09-27 01:50:20 -07001724
1725 down_write(&mm->mmap_sem);
1726 ret = do_munmap(mm, addr, len);
1727 up_write(&mm->mmap_sem);
1728 return ret;
1729}
Linus Torvaldsa46ef992012-04-20 16:20:01 -07001730EXPORT_SYMBOL(vm_munmap);
1731
1732SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1733{
Al Virobfce2812012-04-20 21:57:04 -04001734 return vm_munmap(addr, len);
Linus Torvaldsa46ef992012-04-20 16:20:01 -07001735}
David Howells30340972006-09-27 01:50:20 -07001736
1737/*
David Howells8feae132009-01-08 12:04:47 +00001738 * release all the mappings made in a process's VM space
David Howells30340972006-09-27 01:50:20 -07001739 */
David Howells8feae132009-01-08 12:04:47 +00001740void exit_mmap(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741{
David Howells8feae132009-01-08 12:04:47 +00001742 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743
David Howells8feae132009-01-08 12:04:47 +00001744 if (!mm)
1745 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746
David Howells8feae132009-01-08 12:04:47 +00001747 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748
David Howells8feae132009-01-08 12:04:47 +00001749 mm->total_vm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001750
David Howells8feae132009-01-08 12:04:47 +00001751 while ((vma = mm->mmap)) {
1752 mm->mmap = vma->vm_next;
1753 delete_vma_from_mm(vma);
1754 delete_vma(mm, vma);
Steven J. Magnani04c34962010-11-24 12:56:54 -08001755 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756 }
David Howells8feae132009-01-08 12:04:47 +00001757
1758 kleave("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759}
1760
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07001761unsigned long vm_brk(unsigned long addr, unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001762{
1763 return -ENOMEM;
1764}
1765
1766/*
David Howells6fa5f802006-09-27 01:50:21 -07001767 * expand (or shrink) an existing mapping, potentially moving it at the same
1768 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 *
David Howells6fa5f802006-09-27 01:50:21 -07001770 * under NOMMU conditions, we only permit changing a mapping's size, and only
David Howells8feae132009-01-08 12:04:47 +00001771 * as long as it stays within the region allocated by do_mmap_private() and the
1772 * block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 *
David Howells6fa5f802006-09-27 01:50:21 -07001774 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001775 */
Al Viro4b377ba2013-03-04 10:47:59 -05001776static unsigned long do_mremap(unsigned long addr,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001777 unsigned long old_len, unsigned long new_len,
1778 unsigned long flags, unsigned long new_addr)
1779{
David Howells6fa5f802006-09-27 01:50:21 -07001780 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781
1782 /* insanity checks first */
Bob Liuf67d9b12011-05-24 17:12:56 -07001783 old_len = PAGE_ALIGN(old_len);
1784 new_len = PAGE_ALIGN(new_len);
David Howells8feae132009-01-08 12:04:47 +00001785 if (old_len == 0 || new_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786 return (unsigned long) -EINVAL;
1787
David Howells8feae132009-01-08 12:04:47 +00001788 if (addr & ~PAGE_MASK)
1789 return -EINVAL;
1790
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 if (flags & MREMAP_FIXED && new_addr != addr)
1792 return (unsigned long) -EINVAL;
1793
David Howells8feae132009-01-08 12:04:47 +00001794 vma = find_vma_exact(current->mm, addr, old_len);
David Howells6fa5f802006-09-27 01:50:21 -07001795 if (!vma)
1796 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001797
David Howells6fa5f802006-09-27 01:50:21 -07001798 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 return (unsigned long) -EFAULT;
1800
David Howells6fa5f802006-09-27 01:50:21 -07001801 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802 return (unsigned long) -EPERM;
1803
David Howells8feae132009-01-08 12:04:47 +00001804 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001805 return (unsigned long) -ENOMEM;
1806
1807 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001808 vma->vm_end = vma->vm_start + new_len;
David Howells6fa5f802006-09-27 01:50:21 -07001809 return vma->vm_start;
1810}
1811
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001812SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1813 unsigned long, new_len, unsigned long, flags,
1814 unsigned long, new_addr)
David Howells6fa5f802006-09-27 01:50:21 -07001815{
1816 unsigned long ret;
1817
1818 down_write(&current->mm->mmap_sem);
1819 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1820 up_write(&current->mm->mmap_sem);
1821 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822}
1823
Michel Lespinasse240aade2013-02-22 16:35:56 -08001824struct page *follow_page_mask(struct vm_area_struct *vma,
1825 unsigned long address, unsigned int flags,
1826 unsigned int *page_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827{
Michel Lespinasse240aade2013-02-22 16:35:56 -08001828 *page_mask = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 return NULL;
1830}
1831
Bob Liu8f3b1322011-07-08 15:39:46 -07001832int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1833 unsigned long pfn, unsigned long size, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834{
Bob Liu8f3b1322011-07-08 15:39:46 -07001835 if (addr != (pfn << PAGE_SHIFT))
1836 return -EINVAL;
1837
Konstantin Khlebnikov314e51b2012-10-08 16:29:02 -07001838 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001839 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840}
Luke Yang22c4af42006-07-14 00:24:09 -07001841EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842
Linus Torvalds3c0b9de2013-04-27 13:25:38 -07001843int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1844{
1845 unsigned long pfn = start >> PAGE_SHIFT;
1846 unsigned long vm_len = vma->vm_end - vma->vm_start;
1847
1848 pfn += vma->vm_pgoff;
1849 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1850}
1851EXPORT_SYMBOL(vm_iomap_memory);
1852
Paul Mundtf905bc42008-02-04 22:29:59 -08001853int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1854 unsigned long pgoff)
1855{
1856 unsigned int size = vma->vm_end - vma->vm_start;
1857
1858 if (!(vma->vm_flags & VM_USERMAP))
1859 return -EINVAL;
1860
1861 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1862 vma->vm_end = vma->vm_start + size;
1863
1864 return 0;
1865}
1866EXPORT_SYMBOL(remap_vmalloc_range);
1867
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1869 unsigned long len, unsigned long pgoff, unsigned long flags)
1870{
1871 return -ENOMEM;
1872}
1873
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874void unmap_mapping_range(struct address_space *mapping,
1875 loff_t const holebegin, loff_t const holelen,
1876 int even_cows)
1877{
1878}
Luke Yang22c4af42006-07-14 00:24:09 -07001879EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001880
1881/*
1882 * Check that a process has enough memory to allocate a new virtual
1883 * mapping. 0 means there is enough memory for the allocation to
1884 * succeed and -ENOMEM implies there is not.
1885 *
1886 * We currently support three overcommit policies, which are set via the
1887 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1888 *
1889 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1890 * Additional code 2002 Jul 20 by Robert Love.
1891 *
1892 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1893 *
1894 * Note this is a helper function intended to be used by LSMs which
1895 * wish to use this logic.
1896 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001897int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898{
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07001899 unsigned long free, allowed, reserve;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001900
1901 vm_acct_memory(pages);
1902
1903 /*
1904 * Sometimes we want to use more memory than we have
1905 */
1906 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1907 return 0;
1908
1909 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
Dmitry Finkc15bef32011-07-25 17:12:19 -07001910 free = global_page_state(NR_FREE_PAGES);
1911 free += global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001912
Dmitry Finkc15bef32011-07-25 17:12:19 -07001913 /*
1914 * shmem pages shouldn't be counted as free in this
1915 * case, they can't be purged, only swapped out, and
1916 * that won't affect the overall amount of available
1917 * memory in the system.
1918 */
1919 free -= global_page_state(NR_SHMEM);
1920
Shaohua Liec8acf22013-02-22 16:34:38 -08001921 free += get_nr_swap_pages();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922
1923 /*
1924 * Any slabs which are created with the
1925 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1926 * which are reclaimable, under pressure. The dentry
1927 * cache and most inode caches should fall into this
1928 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001929 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930
1931 /*
Dmitry Finkc15bef32011-07-25 17:12:19 -07001932 * Leave reserved pages. The pages are not for anonymous pages.
1933 */
1934 if (free <= totalreserve_pages)
1935 goto error;
1936 else
1937 free -= totalreserve_pages;
1938
1939 /*
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07001940 * Reserve some for root
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941 */
1942 if (!cap_sys_admin)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07001943 free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944
1945 if (free > pages)
1946 return 0;
1947
Hideo AOKId5ddc792006-04-10 22:53:01 -07001948 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949 }
1950
Jerome Marchand00619bc2013-11-12 15:08:31 -08001951 allowed = vm_commit_limit();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001952 /*
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07001953 * Reserve some 3% for root
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 */
1955 if (!cap_sys_admin)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07001956 allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07001958 /*
1959 * Don't let a single process grow so big a user can't recover
1960 */
1961 if (mm) {
1962 reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
1963 allowed -= min(mm->total_vm / 32, reserve);
1964 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001965
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001966 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 return 0;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001968
Hideo AOKId5ddc792006-04-10 22:53:01 -07001969error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970 vm_unacct_memory(pages);
1971
1972 return -ENOMEM;
1973}
1974
Stephen Wilsoncae5d392011-03-13 15:49:17 -04001975int in_gate_area_no_mm(unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976{
1977 return 0;
1978}
David Howellsb0e15192006-01-06 00:11:42 -08001979
Nick Piggind0217ac2007-07-19 01:47:03 -07001980int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001981{
1982 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001983 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001984}
Paul Mundtb5073172007-07-21 04:37:25 -07001985EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001986
Konstantin Khlebnikov0b173bc2012-10-08 16:28:46 -07001987int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
1988 unsigned long size, pgoff_t pgoff)
1989{
1990 BUG();
1991 return 0;
1992}
1993EXPORT_SYMBOL(generic_file_remap_pages);
1994
Mike Frysingerf55f1992011-03-29 14:05:12 +01001995static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1996 unsigned long addr, void *buf, int len, int write)
David Howells0ec76a12006-09-27 01:50:15 -07001997{
David Howells0ec76a12006-09-27 01:50:15 -07001998 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07001999
2000 down_read(&mm->mmap_sem);
2001
2002 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07002003 vma = find_vma(mm, addr);
2004 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07002005 /* don't overrun this mapping */
2006 if (addr + len >= vma->vm_end)
2007 len = vma->vm_end - addr;
2008
2009 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07002010 if (write && vma->vm_flags & VM_MAYWRITE)
Jie Zhang79597222010-01-06 17:23:28 +00002011 copy_to_user_page(vma, NULL, addr,
2012 (void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07002013 else if (!write && vma->vm_flags & VM_MAYREAD)
Jie Zhang79597222010-01-06 17:23:28 +00002014 copy_from_user_page(vma, NULL, addr,
2015 buf, (void *) addr, len);
David Howells0ec76a12006-09-27 01:50:15 -07002016 else
2017 len = 0;
2018 } else {
2019 len = 0;
2020 }
2021
2022 up_read(&mm->mmap_sem);
Mike Frysingerf55f1992011-03-29 14:05:12 +01002023
2024 return len;
2025}
2026
2027/**
2028 * @access_remote_vm - access another process' address space
2029 * @mm: the mm_struct of the target address space
2030 * @addr: start address to access
2031 * @buf: source or destination buffer
2032 * @len: number of bytes to transfer
2033 * @write: whether the access is a write
2034 *
2035 * The caller must hold a reference on @mm.
2036 */
2037int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2038 void *buf, int len, int write)
2039{
2040 return __access_remote_vm(NULL, mm, addr, buf, len, write);
2041}
2042
2043/*
2044 * Access another process' address space.
2045 * - source/target buffer must be kernel space
2046 */
2047int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2048{
2049 struct mm_struct *mm;
2050
2051 if (addr + len < addr)
2052 return 0;
2053
2054 mm = get_task_mm(tsk);
2055 if (!mm)
2056 return 0;
2057
2058 len = __access_remote_vm(tsk, mm, addr, buf, len, write);
2059
David Howells0ec76a12006-09-27 01:50:15 -07002060 mmput(mm);
2061 return len;
2062}
David Howells7e660872010-01-15 17:01:39 -08002063
2064/**
2065 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
2066 * @inode: The inode to check
2067 * @size: The current filesize of the inode
2068 * @newsize: The proposed filesize of the inode
2069 *
2070 * Check the shared mappings on an inode on behalf of a shrinking truncate to
2071 * make sure that that any outstanding VMAs aren't broken and then shrink the
2072 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
2073 * automatically grant mappings that are too large.
2074 */
2075int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
2076 size_t newsize)
2077{
2078 struct vm_area_struct *vma;
David Howells7e660872010-01-15 17:01:39 -08002079 struct vm_region *region;
2080 pgoff_t low, high;
2081 size_t r_size, r_top;
2082
2083 low = newsize >> PAGE_SHIFT;
2084 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2085
2086 down_write(&nommu_region_sem);
David Howells918e5562012-02-23 13:50:35 +00002087 mutex_lock(&inode->i_mapping->i_mmap_mutex);
David Howells7e660872010-01-15 17:01:39 -08002088
2089 /* search for VMAs that fall within the dead zone */
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -07002090 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
David Howells7e660872010-01-15 17:01:39 -08002091 /* found one - only interested if it's shared out of the page
2092 * cache */
2093 if (vma->vm_flags & VM_SHARED) {
David Howells918e5562012-02-23 13:50:35 +00002094 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
David Howells7e660872010-01-15 17:01:39 -08002095 up_write(&nommu_region_sem);
2096 return -ETXTBSY; /* not quite true, but near enough */
2097 }
2098 }
2099
2100 /* reduce any regions that overlap the dead zone - if in existence,
2101 * these will be pointed to by VMAs that don't overlap the dead zone
2102 *
2103 * we don't check for any regions that start beyond the EOF as there
2104 * shouldn't be any
2105 */
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -07002106 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap,
2107 0, ULONG_MAX) {
David Howells7e660872010-01-15 17:01:39 -08002108 if (!(vma->vm_flags & VM_SHARED))
2109 continue;
2110
2111 region = vma->vm_region;
2112 r_size = region->vm_top - region->vm_start;
2113 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
2114
2115 if (r_top > newsize) {
2116 region->vm_top -= r_top - newsize;
2117 if (region->vm_end > region->vm_top)
2118 region->vm_end = region->vm_top;
2119 }
2120 }
2121
David Howells918e5562012-02-23 13:50:35 +00002122 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
David Howells7e660872010-01-15 17:01:39 -08002123 up_write(&nommu_region_sem);
2124 return 0;
2125}
Andrew Shewmakerc9b1d092013-04-29 15:08:10 -07002126
2127/*
2128 * Initialise sysctl_user_reserve_kbytes.
2129 *
2130 * This is intended to prevent a user from starting a single memory hogging
2131 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
2132 * mode.
2133 *
2134 * The default value is min(3% of free memory, 128MB)
2135 * 128MB is enough to recover with sshd/login, bash, and top/kill.
2136 */
2137static int __meminit init_user_reserve(void)
2138{
2139 unsigned long free_kbytes;
2140
2141 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
2142
2143 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
2144 return 0;
2145}
2146module_init(init_user_reserve)
Andrew Shewmaker4eeab4f2013-04-29 15:08:11 -07002147
2148/*
2149 * Initialise sysctl_admin_reserve_kbytes.
2150 *
2151 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
2152 * to log in and kill a memory hogging process.
2153 *
2154 * Systems with more than 256MB will reserve 8MB, enough to recover
2155 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
2156 * only reserve 3% of free pages by default.
2157 */
2158static int __meminit init_admin_reserve(void)
2159{
2160 unsigned long free_kbytes;
2161
2162 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
2163
2164 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
2165 return 0;
2166}
2167module_init(init_admin_reserve)