blob: 2f3ea749c3184057559cc06ef60960d39bb4bac2 [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;
59unsigned long num_physpages;
Hugh Dickins4266c972009-09-23 17:05:53 +010060unsigned long highest_memmap_pfn;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -070061struct percpu_counter vm_committed_as;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
63int sysctl_overcommit_ratio = 50; /* default is 50% */
64int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
David Howellsfc4d5c22009-05-06 16:03:05 -070065int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066int heap_stack_gap = 0;
67
David Howells33e5d7692009-04-02 16:56:32 -070068atomic_long_t mmap_pages_allocated;
David Howells8feae132009-01-08 12:04:47 +000069
K. Y. Srinivasan997071b2012-11-15 14:34:42 -080070/*
71 * The global memory commitment made in the system can be a metric
72 * that can be used to drive ballooning decisions when Linux is hosted
73 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
74 * balancing memory across competing virtual machines that are hosted.
75 * Several metrics drive this policy engine including the guest reported
76 * memory commitment.
77 */
78unsigned long vm_memory_committed(void)
79{
80 return percpu_counter_read_positive(&vm_committed_as);
81}
82
83EXPORT_SYMBOL_GPL(vm_memory_committed);
84
Linus Torvalds1da177e2005-04-16 15:20:36 -070085EXPORT_SYMBOL(mem_map);
Wu, Bryan6a04de62007-04-11 23:28:47 -070086EXPORT_SYMBOL(num_physpages);
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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700231DEFINE_RWLOCK(vmlist_lock);
232struct vm_struct *vmlist;
233
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800234void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235{
236 kfree(addr);
237}
Paul Mundtb5073172007-07-21 04:37:25 -0700238EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
Al Virodd0fc662005-10-07 07:46:04 +0100240void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241{
242 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200243 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
244 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 */
Nick Piggin84097512006-03-22 00:08:34 -0800246 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247}
Paul Mundtb5073172007-07-21 04:37:25 -0700248EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249
Paul Mundtf905bc42008-02-04 22:29:59 -0800250void *vmalloc_user(unsigned long size)
251{
252 void *ret;
253
254 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
255 PAGE_KERNEL);
256 if (ret) {
257 struct vm_area_struct *vma;
258
259 down_write(&current->mm->mmap_sem);
260 vma = find_vma(current->mm, (unsigned long)ret);
261 if (vma)
262 vma->vm_flags |= VM_USERMAP;
263 up_write(&current->mm->mmap_sem);
264 }
265
266 return ret;
267}
268EXPORT_SYMBOL(vmalloc_user);
269
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800270struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271{
272 return virt_to_page(addr);
273}
Paul Mundtb5073172007-07-21 04:37:25 -0700274EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800276unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277{
278 return page_to_pfn(virt_to_page(addr));
279}
Paul Mundtb5073172007-07-21 04:37:25 -0700280EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281
282long vread(char *buf, char *addr, unsigned long count)
283{
284 memcpy(buf, addr, count);
285 return count;
286}
287
288long vwrite(char *buf, char *addr, unsigned long count)
289{
290 /* Don't allow overflow */
291 if ((unsigned long) addr + count < count)
292 count = -(unsigned long) addr;
293
294 memcpy(addr, buf, count);
295 return(count);
296}
297
298/*
299 * vmalloc - allocate virtually continguos memory
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 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200306 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 * use __vmalloc() instead.
308 */
309void *vmalloc(unsigned long size)
310{
311 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
312}
Andrew Mortonf6138882006-02-28 16:59:18 -0800313EXPORT_SYMBOL(vmalloc);
314
Dave Younge1ca7782010-10-26 14:22:06 -0700315/*
316 * vzalloc - allocate virtually continguos memory with zero fill
317 *
318 * @size: allocation size
319 *
320 * Allocate enough pages to cover @size from the page level
321 * allocator and map them into continguos kernel virtual space.
322 * The memory allocated is set to zero.
323 *
324 * For tight control over page level allocator and protection flags
325 * use __vmalloc() instead.
326 */
327void *vzalloc(unsigned long size)
328{
329 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
330 PAGE_KERNEL);
331}
332EXPORT_SYMBOL(vzalloc);
333
334/**
335 * vmalloc_node - allocate memory on a specific node
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 *
342 * For tight control over page level allocator and protection flags
343 * use __vmalloc() instead.
344 */
Andrew Mortonf6138882006-02-28 16:59:18 -0800345void *vmalloc_node(unsigned long size, int node)
346{
347 return vmalloc(size);
348}
Paul Mundt9a14f652010-12-24 11:50:34 +0900349EXPORT_SYMBOL(vmalloc_node);
Dave Younge1ca7782010-10-26 14:22:06 -0700350
351/**
352 * vzalloc_node - allocate memory on a specific node with zero fill
353 * @size: allocation size
354 * @node: numa node
355 *
356 * Allocate enough pages to cover @size from the page level
357 * allocator and map them into contiguous kernel virtual space.
358 * The memory allocated is set to zero.
359 *
360 * For tight control over page level allocator and protection flags
361 * use __vmalloc() instead.
362 */
363void *vzalloc_node(unsigned long size, int node)
364{
365 return vzalloc(size);
366}
367EXPORT_SYMBOL(vzalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368
Paul Mundt1af446e2008-08-04 16:01:47 +0900369#ifndef PAGE_KERNEL_EXEC
370# define PAGE_KERNEL_EXEC PAGE_KERNEL
371#endif
372
373/**
374 * vmalloc_exec - allocate virtually contiguous, executable memory
375 * @size: allocation size
376 *
377 * Kernel-internal function to allocate enough pages to cover @size
378 * the page level allocator and map them into contiguous and
379 * executable kernel virtual space.
380 *
381 * For tight control over page level allocator and protection flags
382 * use __vmalloc() instead.
383 */
384
385void *vmalloc_exec(unsigned long size)
386{
387 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
388}
389
Paul Mundtb5073172007-07-21 04:37:25 -0700390/**
391 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 * @size: allocation size
393 *
394 * Allocate enough 32bit PA addressable pages to cover @size from the
395 * page level allocator and map them into continguos kernel virtual space.
396 */
397void *vmalloc_32(unsigned long size)
398{
399 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
400}
Paul Mundtb5073172007-07-21 04:37:25 -0700401EXPORT_SYMBOL(vmalloc_32);
402
403/**
404 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
405 * @size: allocation size
406 *
407 * The resulting memory area is 32bit addressable and zeroed so it can be
408 * mapped to userspace without leaking data.
Paul Mundtf905bc42008-02-04 22:29:59 -0800409 *
410 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
411 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700412 */
413void *vmalloc_32_user(unsigned long size)
414{
Paul Mundtf905bc42008-02-04 22:29:59 -0800415 /*
416 * We'll have to sort out the ZONE_DMA bits for 64-bit,
417 * but for now this can simply use vmalloc_user() directly.
418 */
419 return vmalloc_user(size);
Paul Mundtb5073172007-07-21 04:37:25 -0700420}
421EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422
423void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
424{
425 BUG();
426 return NULL;
427}
Paul Mundtb5073172007-07-21 04:37:25 -0700428EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800430void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431{
432 BUG();
433}
Paul Mundtb5073172007-07-21 04:37:25 -0700434EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
Paul Mundteb6434d2009-01-21 17:45:47 +0900436void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
437{
438 BUG();
439 return NULL;
440}
441EXPORT_SYMBOL(vm_map_ram);
442
443void vm_unmap_ram(const void *mem, unsigned int count)
444{
445 BUG();
446}
447EXPORT_SYMBOL(vm_unmap_ram);
448
449void vm_unmap_aliases(void)
450{
451}
452EXPORT_SYMBOL_GPL(vm_unmap_aliases);
453
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700455 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
456 * have one.
457 */
458void __attribute__((weak)) vmalloc_sync_all(void)
459{
460}
461
Paul Mundt29c185e2010-12-24 12:08:30 +0900462/**
463 * alloc_vm_area - allocate a range of kernel address space
464 * @size: size of the area
465 *
466 * Returns: NULL on failure, vm_struct on success
467 *
468 * This function reserves a range of kernel address space, and
469 * allocates pagetables to map that range. No actual mappings
470 * are created. If the kernel address space is not shared
471 * between processes, it syncs the pagetable across all
472 * processes.
473 */
David Vrabelcd129092011-09-29 16:53:32 +0100474struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
Paul Mundt29c185e2010-12-24 12:08:30 +0900475{
476 BUG();
477 return NULL;
478}
479EXPORT_SYMBOL_GPL(alloc_vm_area);
480
481void free_vm_area(struct vm_struct *area)
482{
483 BUG();
484}
485EXPORT_SYMBOL_GPL(free_vm_area);
486
Paul Mundtb5073172007-07-21 04:37:25 -0700487int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
488 struct page *page)
489{
490 return -EINVAL;
491}
492EXPORT_SYMBOL(vm_insert_page);
493
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700494/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 * sys_brk() for the most part doesn't need the global kernel
496 * lock, except when an application is doing something nasty
497 * like trying to un-brk an area that has already been mapped
498 * to a regular file. in this case, the unmapping will need
499 * to invoke file system routines that need the global lock.
500 */
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100501SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502{
503 struct mm_struct *mm = current->mm;
504
505 if (brk < mm->start_brk || brk > mm->context.end_brk)
506 return mm->brk;
507
508 if (mm->brk == brk)
509 return mm->brk;
510
511 /*
512 * Always allow shrinking brk
513 */
514 if (brk <= mm->brk) {
515 mm->brk = brk;
516 return brk;
517 }
518
519 /*
520 * Ok, looks good - let it rip.
521 */
Mike Frysingercfe79c02010-01-06 17:23:23 +0000522 flush_icache_range(mm->brk, brk);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 return mm->brk = brk;
524}
525
David Howells8feae132009-01-08 12:04:47 +0000526/*
527 * initialise the VMA and region record slabs
528 */
529void __init mmap_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700531 int ret;
532
533 ret = percpu_counter_init(&vm_committed_as, 0);
534 VM_BUG_ON(ret);
David Howells33e5d7692009-04-02 16:56:32 -0700535 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
David Howells8feae132009-01-08 12:04:47 +0000536}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537
David Howells8feae132009-01-08 12:04:47 +0000538/*
539 * validate the region tree
540 * - the caller must hold the region lock
541 */
542#ifdef CONFIG_DEBUG_NOMMU_REGIONS
543static noinline void validate_nommu_regions(void)
544{
545 struct vm_region *region, *last;
546 struct rb_node *p, *lastp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547
David Howells8feae132009-01-08 12:04:47 +0000548 lastp = rb_first(&nommu_region_tree);
549 if (!lastp)
550 return;
551
552 last = rb_entry(lastp, struct vm_region, vm_rb);
David Howells33e5d7692009-04-02 16:56:32 -0700553 BUG_ON(unlikely(last->vm_end <= last->vm_start));
554 BUG_ON(unlikely(last->vm_top < last->vm_end));
David Howells8feae132009-01-08 12:04:47 +0000555
556 while ((p = rb_next(lastp))) {
557 region = rb_entry(p, struct vm_region, vm_rb);
558 last = rb_entry(lastp, struct vm_region, vm_rb);
559
David Howells33e5d7692009-04-02 16:56:32 -0700560 BUG_ON(unlikely(region->vm_end <= region->vm_start));
561 BUG_ON(unlikely(region->vm_top < region->vm_end));
562 BUG_ON(unlikely(region->vm_start < last->vm_top));
David Howells8feae132009-01-08 12:04:47 +0000563
564 lastp = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 }
566}
David Howells8feae132009-01-08 12:04:47 +0000567#else
David Howells33e5d7692009-04-02 16:56:32 -0700568static void validate_nommu_regions(void)
569{
570}
David Howells8feae132009-01-08 12:04:47 +0000571#endif
572
573/*
574 * add a region into the global tree
575 */
576static void add_nommu_region(struct vm_region *region)
577{
578 struct vm_region *pregion;
579 struct rb_node **p, *parent;
580
581 validate_nommu_regions();
582
David Howells8feae132009-01-08 12:04:47 +0000583 parent = NULL;
584 p = &nommu_region_tree.rb_node;
585 while (*p) {
586 parent = *p;
587 pregion = rb_entry(parent, struct vm_region, vm_rb);
588 if (region->vm_start < pregion->vm_start)
589 p = &(*p)->rb_left;
590 else if (region->vm_start > pregion->vm_start)
591 p = &(*p)->rb_right;
592 else if (pregion == region)
593 return;
594 else
595 BUG();
596 }
597
598 rb_link_node(&region->vm_rb, parent, p);
599 rb_insert_color(&region->vm_rb, &nommu_region_tree);
600
601 validate_nommu_regions();
602}
603
604/*
605 * delete a region from the global tree
606 */
607static void delete_nommu_region(struct vm_region *region)
608{
609 BUG_ON(!nommu_region_tree.rb_node);
610
611 validate_nommu_regions();
612 rb_erase(&region->vm_rb, &nommu_region_tree);
613 validate_nommu_regions();
614}
615
616/*
617 * free a contiguous series of pages
618 */
619static void free_page_series(unsigned long from, unsigned long to)
620{
621 for (; from < to; from += PAGE_SIZE) {
622 struct page *page = virt_to_page(from);
623
624 kdebug("- free %lx", from);
David Howells33e5d7692009-04-02 16:56:32 -0700625 atomic_long_dec(&mmap_pages_allocated);
David Howells8feae132009-01-08 12:04:47 +0000626 if (page_count(page) != 1)
David Howells33e5d7692009-04-02 16:56:32 -0700627 kdebug("free page %p: refcount not one: %d",
628 page, page_count(page));
David Howells8feae132009-01-08 12:04:47 +0000629 put_page(page);
630 }
631}
632
633/*
634 * release a reference to a region
David Howells33e5d7692009-04-02 16:56:32 -0700635 * - the caller must hold the region semaphore for writing, which this releases
Paul Mundtdd8632a2009-01-08 12:04:47 +0000636 * - the region may not have been added to the tree yet, in which case vm_top
David Howells8feae132009-01-08 12:04:47 +0000637 * will equal vm_start
638 */
639static void __put_nommu_region(struct vm_region *region)
640 __releases(nommu_region_sem)
641{
David Howells1e2ae592010-01-15 17:01:33 -0800642 kenter("%p{%d}", region, region->vm_usage);
David Howells8feae132009-01-08 12:04:47 +0000643
644 BUG_ON(!nommu_region_tree.rb_node);
645
David Howells1e2ae592010-01-15 17:01:33 -0800646 if (--region->vm_usage == 0) {
Paul Mundtdd8632a2009-01-08 12:04:47 +0000647 if (region->vm_top > region->vm_start)
David Howells8feae132009-01-08 12:04:47 +0000648 delete_nommu_region(region);
649 up_write(&nommu_region_sem);
650
651 if (region->vm_file)
652 fput(region->vm_file);
653
654 /* IO memory and memory shared directly out of the pagecache
655 * from ramfs/tmpfs mustn't be released here */
656 if (region->vm_flags & VM_MAPPED_COPY) {
657 kdebug("free series");
Paul Mundtdd8632a2009-01-08 12:04:47 +0000658 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +0000659 }
660 kmem_cache_free(vm_region_jar, region);
661 } else {
662 up_write(&nommu_region_sem);
663 }
664}
665
666/*
667 * release a reference to a region
668 */
669static void put_nommu_region(struct vm_region *region)
670{
671 down_write(&nommu_region_sem);
672 __put_nommu_region(region);
673}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674
David Howells30340972006-09-27 01:50:20 -0700675/*
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700676 * update protection on a vma
677 */
678static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
679{
680#ifdef CONFIG_MPU
681 struct mm_struct *mm = vma->vm_mm;
682 long start = vma->vm_start & PAGE_MASK;
683 while (start < vma->vm_end) {
684 protect_page(mm, start, flags);
685 start += PAGE_SIZE;
686 }
687 update_protections(mm);
688#endif
689}
690
691/*
David Howells30340972006-09-27 01:50:20 -0700692 * add a VMA into a process's mm_struct in the appropriate place in the list
David Howells8feae132009-01-08 12:04:47 +0000693 * and tree and add to the address space's page tree also if not an anonymous
694 * page
David Howells30340972006-09-27 01:50:20 -0700695 * - should be called with mm->mmap_sem held writelocked
696 */
David Howells8feae132009-01-08 12:04:47 +0000697static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
David Howells30340972006-09-27 01:50:20 -0700698{
Namhyung Kim6038def2011-05-24 17:11:22 -0700699 struct vm_area_struct *pvma, *prev;
David Howells8feae132009-01-08 12:04:47 +0000700 struct address_space *mapping;
Namhyung Kim6038def2011-05-24 17:11:22 -0700701 struct rb_node **p, *parent, *rb_prev;
David Howells30340972006-09-27 01:50:20 -0700702
David Howells8feae132009-01-08 12:04:47 +0000703 kenter(",%p", vma);
704
705 BUG_ON(!vma->vm_region);
706
707 mm->map_count++;
708 vma->vm_mm = mm;
709
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700710 protect_vma(vma, vma->vm_flags);
711
David Howells8feae132009-01-08 12:04:47 +0000712 /* add the VMA to the mapping */
713 if (vma->vm_file) {
714 mapping = vma->vm_file->f_mapping;
715
David Howells918e5562012-02-23 13:50:35 +0000716 mutex_lock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000717 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700718 vma_interval_tree_insert(vma, &mapping->i_mmap);
David Howells8feae132009-01-08 12:04:47 +0000719 flush_dcache_mmap_unlock(mapping);
David Howells918e5562012-02-23 13:50:35 +0000720 mutex_unlock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000721 }
722
723 /* add the VMA to the tree */
Namhyung Kim6038def2011-05-24 17:11:22 -0700724 parent = rb_prev = NULL;
David Howells8feae132009-01-08 12:04:47 +0000725 p = &mm->mm_rb.rb_node;
726 while (*p) {
727 parent = *p;
728 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
729
730 /* sort by: start addr, end addr, VMA struct addr in that order
731 * (the latter is necessary as we may get identical VMAs) */
732 if (vma->vm_start < pvma->vm_start)
733 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700734 else if (vma->vm_start > pvma->vm_start) {
735 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000736 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700737 } else if (vma->vm_end < pvma->vm_end)
David Howells8feae132009-01-08 12:04:47 +0000738 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700739 else if (vma->vm_end > pvma->vm_end) {
740 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000741 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700742 } else if (vma < pvma)
David Howells8feae132009-01-08 12:04:47 +0000743 p = &(*p)->rb_left;
Namhyung Kim6038def2011-05-24 17:11:22 -0700744 else if (vma > pvma) {
745 rb_prev = parent;
David Howells8feae132009-01-08 12:04:47 +0000746 p = &(*p)->rb_right;
Namhyung Kim6038def2011-05-24 17:11:22 -0700747 } else
David Howells8feae132009-01-08 12:04:47 +0000748 BUG();
749 }
750
751 rb_link_node(&vma->vm_rb, parent, p);
752 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
753
754 /* add VMA to the VMA list also */
Namhyung Kim6038def2011-05-24 17:11:22 -0700755 prev = NULL;
756 if (rb_prev)
757 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
David Howells30340972006-09-27 01:50:20 -0700758
Namhyung Kim6038def2011-05-24 17:11:22 -0700759 __vma_link_list(mm, vma, prev, parent);
David Howells8feae132009-01-08 12:04:47 +0000760}
761
762/*
763 * delete a VMA from its owning mm_struct and address space
764 */
765static void delete_vma_from_mm(struct vm_area_struct *vma)
766{
David Howells8feae132009-01-08 12:04:47 +0000767 struct address_space *mapping;
768 struct mm_struct *mm = vma->vm_mm;
769
770 kenter("%p", vma);
771
Bernd Schmidteb8cdec2009-09-21 17:03:57 -0700772 protect_vma(vma, 0);
773
David Howells8feae132009-01-08 12:04:47 +0000774 mm->map_count--;
775 if (mm->mmap_cache == vma)
776 mm->mmap_cache = NULL;
777
778 /* remove the VMA from the mapping */
779 if (vma->vm_file) {
780 mapping = vma->vm_file->f_mapping;
781
David Howells918e5562012-02-23 13:50:35 +0000782 mutex_lock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000783 flush_dcache_mmap_lock(mapping);
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -0700784 vma_interval_tree_remove(vma, &mapping->i_mmap);
David Howells8feae132009-01-08 12:04:47 +0000785 flush_dcache_mmap_unlock(mapping);
David Howells918e5562012-02-23 13:50:35 +0000786 mutex_unlock(&mapping->i_mmap_mutex);
David Howells8feae132009-01-08 12:04:47 +0000787 }
788
789 /* remove from the MM's tree and list */
790 rb_erase(&vma->vm_rb, &mm->mm_rb);
Namhyung Kimb951bf22011-05-24 17:11:23 -0700791
792 if (vma->vm_prev)
793 vma->vm_prev->vm_next = vma->vm_next;
794 else
795 mm->mmap = vma->vm_next;
796
797 if (vma->vm_next)
798 vma->vm_next->vm_prev = vma->vm_prev;
David Howells8feae132009-01-08 12:04:47 +0000799}
800
801/*
802 * destroy a VMA record
803 */
804static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
805{
806 kenter("%p", vma);
807 if (vma->vm_ops && vma->vm_ops->close)
808 vma->vm_ops->close(vma);
Konstantin Khlebnikove9714ac2012-10-08 16:28:54 -0700809 if (vma->vm_file)
David Howells8feae132009-01-08 12:04:47 +0000810 fput(vma->vm_file);
David Howells8feae132009-01-08 12:04:47 +0000811 put_nommu_region(vma->vm_region);
812 kmem_cache_free(vm_area_cachep, vma);
David Howells30340972006-09-27 01:50:20 -0700813}
814
815/*
816 * look up the first VMA in which addr resides, NULL if none
817 * - should be called with mm->mmap_sem at least held readlocked
818 */
819struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
820{
David Howells8feae132009-01-08 12:04:47 +0000821 struct vm_area_struct *vma;
David Howells30340972006-09-27 01:50:20 -0700822
David Howells8feae132009-01-08 12:04:47 +0000823 /* check the cache first */
Jan Stancekb6a9b7f2013-04-04 11:35:10 -0700824 vma = ACCESS_ONCE(mm->mmap_cache);
David Howells8feae132009-01-08 12:04:47 +0000825 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
826 return vma;
827
Namhyung Kime922c4c2011-05-24 17:11:24 -0700828 /* trawl the list (there may be multiple mappings in which addr
David Howells8feae132009-01-08 12:04:47 +0000829 * resides) */
Namhyung Kime922c4c2011-05-24 17:11:24 -0700830 for (vma = mm->mmap; vma; vma = vma->vm_next) {
David Howells8feae132009-01-08 12:04:47 +0000831 if (vma->vm_start > addr)
832 return NULL;
833 if (vma->vm_end > addr) {
834 mm->mmap_cache = vma;
835 return vma;
836 }
David Howells30340972006-09-27 01:50:20 -0700837 }
838
David Howells30340972006-09-27 01:50:20 -0700839 return NULL;
840}
841EXPORT_SYMBOL(find_vma);
842
843/*
David Howells930e6522006-09-27 01:50:22 -0700844 * find a VMA
845 * - we don't extend stack VMAs under NOMMU conditions
846 */
847struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
848{
David Howells7561e8c2010-03-25 16:48:38 +0000849 return find_vma(mm, addr);
David Howells930e6522006-09-27 01:50:22 -0700850}
851
David Howells8feae132009-01-08 12:04:47 +0000852/*
853 * expand a stack to a given address
854 * - not supported under NOMMU conditions
855 */
Greg Ungerer57c8f632007-07-15 23:38:28 -0700856int expand_stack(struct vm_area_struct *vma, unsigned long address)
857{
858 return -ENOMEM;
859}
860
David Howells930e6522006-09-27 01:50:22 -0700861/*
David Howells6fa5f802006-09-27 01:50:21 -0700862 * look up the first VMA exactly that exactly matches addr
863 * - should be called with mm->mmap_sem at least held readlocked
864 */
David Howells8feae132009-01-08 12:04:47 +0000865static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
866 unsigned long addr,
867 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868{
869 struct vm_area_struct *vma;
David Howells8feae132009-01-08 12:04:47 +0000870 unsigned long end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700871
David Howells8feae132009-01-08 12:04:47 +0000872 /* check the cache first */
873 vma = mm->mmap_cache;
874 if (vma && vma->vm_start == addr && vma->vm_end == end)
875 return vma;
876
Namhyung Kime922c4c2011-05-24 17:11:24 -0700877 /* trawl the list (there may be multiple mappings in which addr
David Howells8feae132009-01-08 12:04:47 +0000878 * resides) */
Namhyung Kime922c4c2011-05-24 17:11:24 -0700879 for (vma = mm->mmap; vma; vma = vma->vm_next) {
David Howells8feae132009-01-08 12:04:47 +0000880 if (vma->vm_start < addr)
881 continue;
882 if (vma->vm_start > addr)
883 return NULL;
884 if (vma->vm_end == end) {
885 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 return vma;
David Howells8feae132009-01-08 12:04:47 +0000887 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888 }
889
890 return NULL;
891}
892
David Howells30340972006-09-27 01:50:20 -0700893/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 * determine whether a mapping should be permitted and, if so, what sort of
895 * mapping we're capable of supporting
896 */
897static int validate_mmap_request(struct file *file,
898 unsigned long addr,
899 unsigned long len,
900 unsigned long prot,
901 unsigned long flags,
902 unsigned long pgoff,
903 unsigned long *_capabilities)
904{
David Howells8feae132009-01-08 12:04:47 +0000905 unsigned long capabilities, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 int ret;
907
908 /* do the simple checks first */
David Howells06aab5a2009-09-24 12:33:48 +0100909 if (flags & MAP_FIXED) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 printk(KERN_DEBUG
911 "%d: Can't do fixed-address/overlay mmap of RAM\n",
912 current->pid);
913 return -EINVAL;
914 }
915
916 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
917 (flags & MAP_TYPE) != MAP_SHARED)
918 return -EINVAL;
919
Mike Frysingerf81cff02006-12-06 12:02:59 +1000920 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700921 return -EINVAL;
922
Mike Frysingerf81cff02006-12-06 12:02:59 +1000923 /* Careful about overflows.. */
David Howells8feae132009-01-08 12:04:47 +0000924 rlen = PAGE_ALIGN(len);
925 if (!rlen || rlen > TASK_SIZE)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000926 return -ENOMEM;
927
Linus Torvalds1da177e2005-04-16 15:20:36 -0700928 /* offset overflow? */
David Howells8feae132009-01-08 12:04:47 +0000929 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000930 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931
932 if (file) {
933 /* validate file mapping requests */
934 struct address_space *mapping;
935
936 /* files must support mmap */
937 if (!file->f_op || !file->f_op->mmap)
938 return -ENODEV;
939
940 /* work out if what we've got could possibly be shared
941 * - we support chardevs that provide their own "memory"
942 * - we support files/blockdevs that are memory backed
943 */
944 mapping = file->f_mapping;
945 if (!mapping)
Al Viro496ad9a2013-01-23 17:07:38 -0500946 mapping = file_inode(file)->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947
948 capabilities = 0;
949 if (mapping && mapping->backing_dev_info)
950 capabilities = mapping->backing_dev_info->capabilities;
951
952 if (!capabilities) {
953 /* no explicit capabilities set, so assume some
954 * defaults */
Al Viro496ad9a2013-01-23 17:07:38 -0500955 switch (file_inode(file)->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 case S_IFREG:
957 case S_IFBLK:
958 capabilities = BDI_CAP_MAP_COPY;
959 break;
960
961 case S_IFCHR:
962 capabilities =
963 BDI_CAP_MAP_DIRECT |
964 BDI_CAP_READ_MAP |
965 BDI_CAP_WRITE_MAP;
966 break;
967
968 default:
969 return -EINVAL;
970 }
971 }
972
973 /* eliminate any capabilities that we can't support on this
974 * device */
975 if (!file->f_op->get_unmapped_area)
976 capabilities &= ~BDI_CAP_MAP_DIRECT;
977 if (!file->f_op->read)
978 capabilities &= ~BDI_CAP_MAP_COPY;
979
Graff Yang28d7a6a2009-08-18 14:11:17 -0700980 /* The file shall have been opened with read permission. */
981 if (!(file->f_mode & FMODE_READ))
982 return -EACCES;
983
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984 if (flags & MAP_SHARED) {
985 /* do checks for writing, appending and locking */
986 if ((prot & PROT_WRITE) &&
987 !(file->f_mode & FMODE_WRITE))
988 return -EACCES;
989
Al Viro496ad9a2013-01-23 17:07:38 -0500990 if (IS_APPEND(file_inode(file)) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 (file->f_mode & FMODE_WRITE))
992 return -EACCES;
993
Al Viro496ad9a2013-01-23 17:07:38 -0500994 if (locks_verify_locked(file_inode(file)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 return -EAGAIN;
996
997 if (!(capabilities & BDI_CAP_MAP_DIRECT))
998 return -ENODEV;
999
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 /* we mustn't privatise shared mappings */
1001 capabilities &= ~BDI_CAP_MAP_COPY;
1002 }
1003 else {
1004 /* we're going to read the file into private memory we
1005 * allocate */
1006 if (!(capabilities & BDI_CAP_MAP_COPY))
1007 return -ENODEV;
1008
1009 /* we don't permit a private writable mapping to be
1010 * shared with the backing device */
1011 if (prot & PROT_WRITE)
1012 capabilities &= ~BDI_CAP_MAP_DIRECT;
1013 }
1014
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001015 if (capabilities & BDI_CAP_MAP_DIRECT) {
1016 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
1017 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
1018 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
1019 ) {
1020 capabilities &= ~BDI_CAP_MAP_DIRECT;
1021 if (flags & MAP_SHARED) {
1022 printk(KERN_WARNING
1023 "MAP_SHARED not completely supported on !MMU\n");
1024 return -EINVAL;
1025 }
1026 }
1027 }
1028
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 /* handle executable mappings and implied executable
1030 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -08001031 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 if (prot & PROT_EXEC)
1033 return -EPERM;
1034 }
1035 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
1036 /* handle implication of PROT_EXEC by PROT_READ */
1037 if (current->personality & READ_IMPLIES_EXEC) {
1038 if (capabilities & BDI_CAP_EXEC_MAP)
1039 prot |= PROT_EXEC;
1040 }
1041 }
1042 else if ((prot & PROT_READ) &&
1043 (prot & PROT_EXEC) &&
1044 !(capabilities & BDI_CAP_EXEC_MAP)
1045 ) {
1046 /* backing file is not executable, try to copy */
1047 capabilities &= ~BDI_CAP_MAP_DIRECT;
1048 }
1049 }
1050 else {
1051 /* anonymous mappings are always memory backed and can be
1052 * privately mapped
1053 */
1054 capabilities = BDI_CAP_MAP_COPY;
1055
1056 /* handle PROT_EXEC implication by PROT_READ */
1057 if ((prot & PROT_READ) &&
1058 (current->personality & READ_IMPLIES_EXEC))
1059 prot |= PROT_EXEC;
1060 }
1061
1062 /* allow the security API to have its say */
Al Viroe5467852012-05-30 13:30:51 -04001063 ret = security_mmap_addr(addr);
1064 if (ret < 0)
1065 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001066
1067 /* looks okay */
1068 *_capabilities = capabilities;
1069 return 0;
1070}
1071
1072/*
1073 * we've determined that we can make the mapping, now translate what we
1074 * now know into VMA flags
1075 */
1076static unsigned long determine_vm_flags(struct file *file,
1077 unsigned long prot,
1078 unsigned long flags,
1079 unsigned long capabilities)
1080{
1081 unsigned long vm_flags;
1082
1083 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 /* vm_flags |= mm->def_flags; */
1085
1086 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1087 /* attempt to share read-only copies of mapped file chunks */
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001088 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 if (file && !(prot & PROT_WRITE))
1090 vm_flags |= VM_MAYSHARE;
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001091 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001092 /* overlay a shareable mapping on the backing device or inode
1093 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1094 * romfs/cramfs */
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001095 vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 if (flags & MAP_SHARED)
Bernd Schmidt3c7b2042010-05-25 23:43:00 -07001097 vm_flags |= VM_SHARED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 }
1099
1100 /* refuse to let anyone share private mappings with this process if
1101 * it's being traced - otherwise breakpoints set in it may interfere
1102 * with another untraced process
1103 */
Tejun Heoa288eec2011-06-17 16:50:37 +02001104 if ((flags & MAP_PRIVATE) && current->ptrace)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 vm_flags &= ~VM_MAYSHARE;
1106
1107 return vm_flags;
1108}
1109
1110/*
David Howells8feae132009-01-08 12:04:47 +00001111 * set up a shared mapping on a file (the driver or filesystem provides and
1112 * pins the storage)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 */
David Howells8feae132009-01-08 12:04:47 +00001114static int do_mmap_shared_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001115{
1116 int ret;
1117
1118 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001119 if (ret == 0) {
1120 vma->vm_region->vm_top = vma->vm_region->vm_end;
David Howells645d83c2009-09-24 15:13:10 +01001121 return 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001122 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001123 if (ret != -ENOSYS)
1124 return ret;
1125
David Howells3fa30462010-03-23 13:35:21 -07001126 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1127 * opposed to tried but failed) so we can only give a suitable error as
1128 * it's not possible to make a private copy if MAP_SHARED was given */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001129 return -ENODEV;
1130}
1131
1132/*
1133 * set up a private mapping or an anonymous shared mapping
1134 */
David Howells8feae132009-01-08 12:04:47 +00001135static int do_mmap_private(struct vm_area_struct *vma,
1136 struct vm_region *region,
David Howells645d83c2009-09-24 15:13:10 +01001137 unsigned long len,
1138 unsigned long capabilities)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001139{
David Howells8feae132009-01-08 12:04:47 +00001140 struct page *pages;
Bob Liuf67d9b12011-05-24 17:12:56 -07001141 unsigned long total, point, n;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142 void *base;
David Howells8feae132009-01-08 12:04:47 +00001143 int ret, order;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144
1145 /* invoke the file's mapping function so that it can keep track of
1146 * shared mappings on devices or memory
1147 * - VM_MAYSHARE will be set if it may attempt to share
1148 */
David Howells645d83c2009-09-24 15:13:10 +01001149 if (capabilities & BDI_CAP_MAP_DIRECT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001151 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152 /* shouldn't return success if we're not sharing */
Paul Mundtdd8632a2009-01-08 12:04:47 +00001153 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1154 vma->vm_region->vm_top = vma->vm_region->vm_end;
David Howells645d83c2009-09-24 15:13:10 +01001155 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 }
Paul Mundtdd8632a2009-01-08 12:04:47 +00001157 if (ret != -ENOSYS)
1158 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159
1160 /* getting an ENOSYS error indicates that direct mmap isn't
1161 * possible (as opposed to tried but failed) so we'll try to
1162 * make a private copy of the data and map that instead */
1163 }
1164
David Howells8feae132009-01-08 12:04:47 +00001165
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 /* allocate some memory to hold the mapping
1167 * - note that this may not return a page-aligned address if the object
1168 * we're allocating is smaller than a page
1169 */
Bob Liuf67d9b12011-05-24 17:12:56 -07001170 order = get_order(len);
David Howells8feae132009-01-08 12:04:47 +00001171 kdebug("alloc order %d for %lx", order, len);
1172
1173 pages = alloc_pages(GFP_KERNEL, order);
1174 if (!pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 goto enomem;
1176
David Howells8feae132009-01-08 12:04:47 +00001177 total = 1 << order;
David Howells33e5d7692009-04-02 16:56:32 -07001178 atomic_long_add(total, &mmap_pages_allocated);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179
Bob Liuf67d9b12011-05-24 17:12:56 -07001180 point = len >> PAGE_SHIFT;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001181
1182 /* we allocated a power-of-2 sized page set, so we may want to trim off
1183 * the excess */
1184 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1185 while (total > point) {
1186 order = ilog2(total - point);
1187 n = 1 << order;
1188 kdebug("shave %lu/%lu @%lu", n, total - point, total);
David Howells33e5d7692009-04-02 16:56:32 -07001189 atomic_long_sub(n, &mmap_pages_allocated);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001190 total -= n;
1191 set_page_refcounted(pages + total);
1192 __free_pages(pages + total, order);
1193 }
David Howells8feae132009-01-08 12:04:47 +00001194 }
1195
David Howells8feae132009-01-08 12:04:47 +00001196 for (point = 1; point < total; point++)
1197 set_page_refcounted(&pages[point]);
1198
1199 base = page_address(pages);
1200 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1201 region->vm_start = (unsigned long) base;
Bob Liuf67d9b12011-05-24 17:12:56 -07001202 region->vm_end = region->vm_start + len;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001203 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
David Howells8feae132009-01-08 12:04:47 +00001204
1205 vma->vm_start = region->vm_start;
1206 vma->vm_end = region->vm_start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207
1208 if (vma->vm_file) {
1209 /* read the contents of a file into the copy */
1210 mm_segment_t old_fs;
1211 loff_t fpos;
1212
1213 fpos = vma->vm_pgoff;
1214 fpos <<= PAGE_SHIFT;
1215
1216 old_fs = get_fs();
1217 set_fs(KERNEL_DS);
Bob Liuf67d9b12011-05-24 17:12:56 -07001218 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 set_fs(old_fs);
1220
1221 if (ret < 0)
1222 goto error_free;
1223
1224 /* clear the last little bit */
Bob Liuf67d9b12011-05-24 17:12:56 -07001225 if (ret < len)
1226 memset(base + ret, 0, len - ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 }
1229
1230 return 0;
1231
1232error_free:
Namhyung Kim7223bb42011-05-24 17:11:26 -07001233 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +00001234 region->vm_start = vma->vm_start = 0;
1235 region->vm_end = vma->vm_end = 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001236 region->vm_top = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 return ret;
1238
1239enomem:
Greg Ungerer05ae6fa2009-01-13 17:30:22 +10001240 printk("Allocation of length %lu from process %d (%s) failed\n",
1241 len, current->pid, current->comm);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001242 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 return -ENOMEM;
1244}
1245
1246/*
1247 * handle mapping creation for uClinux
1248 */
Al Viroe3fc6292012-05-30 20:08:42 -04001249unsigned long do_mmap_pgoff(struct file *file,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 unsigned long addr,
1251 unsigned long len,
1252 unsigned long prot,
1253 unsigned long flags,
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001254 unsigned long pgoff,
Michel Lespinasse41badc12013-02-22 16:32:47 -08001255 unsigned long *populate)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256{
David Howells8feae132009-01-08 12:04:47 +00001257 struct vm_area_struct *vma;
1258 struct vm_region *region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 struct rb_node *rb;
David Howells8feae132009-01-08 12:04:47 +00001260 unsigned long capabilities, vm_flags, result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001261 int ret;
1262
David Howells8feae132009-01-08 12:04:47 +00001263 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1264
Michel Lespinasse41badc12013-02-22 16:32:47 -08001265 *populate = 0;
Michel Lespinassebebeb3d2013-02-22 16:32:37 -08001266
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 /* decide whether we should attempt the mapping, and if so what sort of
1268 * mapping */
1269 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1270 &capabilities);
David Howells8feae132009-01-08 12:04:47 +00001271 if (ret < 0) {
1272 kleave(" = %d [val]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 return ret;
David Howells8feae132009-01-08 12:04:47 +00001274 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275
David Howells06aab5a2009-09-24 12:33:48 +01001276 /* we ignore the address hint */
1277 addr = 0;
Bob Liuf67d9b12011-05-24 17:12:56 -07001278 len = PAGE_ALIGN(len);
David Howells06aab5a2009-09-24 12:33:48 +01001279
Linus Torvalds1da177e2005-04-16 15:20:36 -07001280 /* we've determined that we can make the mapping, now translate what we
1281 * now know into VMA flags */
1282 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1283
David Howells8feae132009-01-08 12:04:47 +00001284 /* we're going to need to record the mapping */
1285 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1286 if (!region)
1287 goto error_getting_region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288
David Howells8feae132009-01-08 12:04:47 +00001289 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1290 if (!vma)
1291 goto error_getting_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292
David Howells1e2ae592010-01-15 17:01:33 -08001293 region->vm_usage = 1;
David Howells8feae132009-01-08 12:04:47 +00001294 region->vm_flags = vm_flags;
1295 region->vm_pgoff = pgoff;
1296
Rik van Riel5beb4932010-03-05 13:42:07 -08001297 INIT_LIST_HEAD(&vma->anon_vma_chain);
David Howells8feae132009-01-08 12:04:47 +00001298 vma->vm_flags = vm_flags;
1299 vma->vm_pgoff = pgoff;
1300
1301 if (file) {
Al Virocb0942b2012-08-27 14:48:26 -04001302 region->vm_file = get_file(file);
1303 vma->vm_file = get_file(file);
David Howells8feae132009-01-08 12:04:47 +00001304 }
1305
1306 down_write(&nommu_region_sem);
1307
1308 /* if we want to share, we need to check for regions created by other
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309 * mmap() calls that overlap with our proposed mapping
David Howells8feae132009-01-08 12:04:47 +00001310 * - we can only share with a superset match on most regular files
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 * - shared mappings on character devices and memory backed files are
1312 * permitted to overlap inexactly as far as we are concerned for in
1313 * these cases, sharing is handled in the driver or filesystem rather
1314 * than here
1315 */
1316 if (vm_flags & VM_MAYSHARE) {
David Howells8feae132009-01-08 12:04:47 +00001317 struct vm_region *pregion;
1318 unsigned long pglen, rpglen, pgend, rpgend, start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
David Howells8feae132009-01-08 12:04:47 +00001320 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1321 pgend = pgoff + pglen;
David Howells165b2392007-03-22 00:11:24 -08001322
David Howells8feae132009-01-08 12:04:47 +00001323 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1324 pregion = rb_entry(rb, struct vm_region, vm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325
David Howells8feae132009-01-08 12:04:47 +00001326 if (!(pregion->vm_flags & VM_MAYSHARE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 continue;
1328
1329 /* search for overlapping mappings on the same file */
Al Viro496ad9a2013-01-23 17:07:38 -05001330 if (file_inode(pregion->vm_file) !=
1331 file_inode(file))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 continue;
1333
David Howells8feae132009-01-08 12:04:47 +00001334 if (pregion->vm_pgoff >= pgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 continue;
1336
David Howells8feae132009-01-08 12:04:47 +00001337 rpglen = pregion->vm_end - pregion->vm_start;
1338 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1339 rpgend = pregion->vm_pgoff + rpglen;
1340 if (pgoff >= rpgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 continue;
1342
David Howells8feae132009-01-08 12:04:47 +00001343 /* handle inexactly overlapping matches between
1344 * mappings */
1345 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1346 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1347 /* new mapping is not a subset of the region */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1349 goto sharing_violation;
1350 continue;
1351 }
1352
David Howells8feae132009-01-08 12:04:47 +00001353 /* we've found a region we can share */
David Howells1e2ae592010-01-15 17:01:33 -08001354 pregion->vm_usage++;
David Howells8feae132009-01-08 12:04:47 +00001355 vma->vm_region = pregion;
1356 start = pregion->vm_start;
1357 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1358 vma->vm_start = start;
1359 vma->vm_end = start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360
David Howells8feae132009-01-08 12:04:47 +00001361 if (pregion->vm_flags & VM_MAPPED_COPY) {
1362 kdebug("share copy");
1363 vma->vm_flags |= VM_MAPPED_COPY;
1364 } else {
1365 kdebug("share mmap");
1366 ret = do_mmap_shared_file(vma);
1367 if (ret < 0) {
1368 vma->vm_region = NULL;
1369 vma->vm_start = 0;
1370 vma->vm_end = 0;
David Howells1e2ae592010-01-15 17:01:33 -08001371 pregion->vm_usage--;
David Howells8feae132009-01-08 12:04:47 +00001372 pregion = NULL;
1373 goto error_just_free;
1374 }
1375 }
1376 fput(region->vm_file);
1377 kmem_cache_free(vm_region_jar, region);
1378 region = pregion;
1379 result = start;
1380 goto share;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 }
1382
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 /* obtain the address at which to make a shared mapping
1384 * - this is the hook for quasi-memory character devices to
1385 * tell us the location of a shared mapping
1386 */
David Howells645d83c2009-09-24 15:13:10 +01001387 if (capabilities & BDI_CAP_MAP_DIRECT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 addr = file->f_op->get_unmapped_area(file, addr, len,
1389 pgoff, flags);
Namhyung Kimbb005a52011-05-24 17:11:27 -07001390 if (IS_ERR_VALUE(addr)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 ret = addr;
Namhyung Kimbb005a52011-05-24 17:11:27 -07001392 if (ret != -ENOSYS)
David Howells8feae132009-01-08 12:04:47 +00001393 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001394
1395 /* the driver refused to tell us where to site
1396 * the mapping so we'll have to attempt to copy
1397 * it */
Namhyung Kimbb005a52011-05-24 17:11:27 -07001398 ret = -ENODEV;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 if (!(capabilities & BDI_CAP_MAP_COPY))
David Howells8feae132009-01-08 12:04:47 +00001400 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401
1402 capabilities &= ~BDI_CAP_MAP_DIRECT;
David Howells8feae132009-01-08 12:04:47 +00001403 } else {
1404 vma->vm_start = region->vm_start = addr;
1405 vma->vm_end = region->vm_end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406 }
1407 }
1408 }
1409
David Howells8feae132009-01-08 12:04:47 +00001410 vma->vm_region = region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411
David Howells645d83c2009-09-24 15:13:10 +01001412 /* set up the mapping
1413 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1414 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415 if (file && vma->vm_flags & VM_SHARED)
David Howells8feae132009-01-08 12:04:47 +00001416 ret = do_mmap_shared_file(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 else
David Howells645d83c2009-09-24 15:13:10 +01001418 ret = do_mmap_private(vma, region, len, capabilities);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 if (ret < 0)
David Howells645d83c2009-09-24 15:13:10 +01001420 goto error_just_free;
1421 add_nommu_region(region);
David Howells8feae132009-01-08 12:04:47 +00001422
Jie Zhangea637632009-12-14 18:00:02 -08001423 /* clear anonymous mappings that don't ask for uninitialized data */
1424 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1425 memset((void *)region->vm_start, 0,
1426 region->vm_end - region->vm_start);
1427
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428 /* okay... we have a mapping; now we have to register it */
David Howells8feae132009-01-08 12:04:47 +00001429 result = vma->vm_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 current->mm->total_vm += len >> PAGE_SHIFT;
1432
David Howells8feae132009-01-08 12:04:47 +00001433share:
1434 add_vma_to_mm(current->mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435
Mike Frysingercfe79c02010-01-06 17:23:23 +00001436 /* we flush the region from the icache only when the first executable
1437 * mapping of it is made */
1438 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1439 flush_icache_range(region->vm_start, region->vm_end);
1440 region->vm_icache_flushed = true;
1441 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442
Mike Frysingercfe79c02010-01-06 17:23:23 +00001443 up_write(&nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444
David Howells8feae132009-01-08 12:04:47 +00001445 kleave(" = %lx", result);
1446 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447
David Howells8feae132009-01-08 12:04:47 +00001448error_just_free:
1449 up_write(&nommu_region_sem);
1450error:
David Howells89a86402009-10-30 13:13:26 +00001451 if (region->vm_file)
1452 fput(region->vm_file);
David Howells8feae132009-01-08 12:04:47 +00001453 kmem_cache_free(vm_region_jar, region);
David Howells89a86402009-10-30 13:13:26 +00001454 if (vma->vm_file)
1455 fput(vma->vm_file);
David Howells8feae132009-01-08 12:04:47 +00001456 kmem_cache_free(vm_area_cachep, vma);
1457 kleave(" = %d", ret);
1458 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459
David Howells8feae132009-01-08 12:04:47 +00001460sharing_violation:
1461 up_write(&nommu_region_sem);
1462 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1463 ret = -EINVAL;
1464 goto error;
1465
1466error_getting_vma:
1467 kmem_cache_free(vm_region_jar, region);
1468 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1469 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470 len, current->pid);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001471 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 return -ENOMEM;
1473
David Howells8feae132009-01-08 12:04:47 +00001474error_getting_region:
1475 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1476 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 len, current->pid);
David Rientjes7bf02ea2011-05-24 17:11:16 -07001478 show_free_areas(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 return -ENOMEM;
1480}
Linus Torvalds6be5ceb2012-04-20 17:13:58 -07001481
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001482SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1483 unsigned long, prot, unsigned long, flags,
1484 unsigned long, fd, unsigned long, pgoff)
1485{
1486 struct file *file = NULL;
1487 unsigned long retval = -EBADF;
1488
Al Viro120a7952010-10-30 02:54:44 -04001489 audit_mmap_fd(fd, flags);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001490 if (!(flags & MAP_ANONYMOUS)) {
1491 file = fget(fd);
1492 if (!file)
1493 goto out;
1494 }
1495
1496 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1497
Greg Ungererad1ed292012-06-04 14:29:59 +10001498 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
Hugh Dickins66f0dc42009-12-30 20:17:34 +00001499
1500 if (file)
1501 fput(file);
1502out:
1503 return retval;
1504}
1505
Christoph Hellwiga4679372010-03-10 15:21:15 -08001506#ifdef __ARCH_WANT_SYS_OLD_MMAP
1507struct mmap_arg_struct {
1508 unsigned long addr;
1509 unsigned long len;
1510 unsigned long prot;
1511 unsigned long flags;
1512 unsigned long fd;
1513 unsigned long offset;
1514};
1515
1516SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1517{
1518 struct mmap_arg_struct a;
1519
1520 if (copy_from_user(&a, arg, sizeof(a)))
1521 return -EFAULT;
1522 if (a.offset & ~PAGE_MASK)
1523 return -EINVAL;
1524
1525 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1526 a.offset >> PAGE_SHIFT);
1527}
1528#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1529
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530/*
David Howells8feae132009-01-08 12:04:47 +00001531 * split a vma into two pieces at address 'addr', a new vma is allocated either
1532 * for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 */
David Howells8feae132009-01-08 12:04:47 +00001534int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1535 unsigned long addr, int new_below)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536{
David Howells8feae132009-01-08 12:04:47 +00001537 struct vm_area_struct *new;
1538 struct vm_region *region;
1539 unsigned long npages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001540
David Howells8feae132009-01-08 12:04:47 +00001541 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542
David Howells779c1022010-01-15 17:01:34 -08001543 /* we're only permitted to split anonymous regions (these should have
1544 * only a single usage on the region) */
1545 if (vma->vm_file)
David Howells8feae132009-01-08 12:04:47 +00001546 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547
David Howells8feae132009-01-08 12:04:47 +00001548 if (mm->map_count >= sysctl_max_map_count)
1549 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001550
David Howells8feae132009-01-08 12:04:47 +00001551 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1552 if (!region)
1553 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554
David Howells8feae132009-01-08 12:04:47 +00001555 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1556 if (!new) {
1557 kmem_cache_free(vm_region_jar, region);
1558 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001559 }
David Howells8feae132009-01-08 12:04:47 +00001560
1561 /* most fields are the same, copy all, and then fixup */
1562 *new = *vma;
1563 *region = *vma->vm_region;
1564 new->vm_region = region;
1565
1566 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1567
1568 if (new_below) {
Paul Mundtdd8632a2009-01-08 12:04:47 +00001569 region->vm_top = region->vm_end = new->vm_end = addr;
David Howells8feae132009-01-08 12:04:47 +00001570 } else {
1571 region->vm_start = new->vm_start = addr;
1572 region->vm_pgoff = new->vm_pgoff += npages;
1573 }
1574
1575 if (new->vm_ops && new->vm_ops->open)
1576 new->vm_ops->open(new);
1577
1578 delete_vma_from_mm(vma);
1579 down_write(&nommu_region_sem);
1580 delete_nommu_region(vma->vm_region);
1581 if (new_below) {
1582 vma->vm_region->vm_start = vma->vm_start = addr;
1583 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1584 } else {
1585 vma->vm_region->vm_end = vma->vm_end = addr;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001586 vma->vm_region->vm_top = addr;
David Howells8feae132009-01-08 12:04:47 +00001587 }
1588 add_nommu_region(vma->vm_region);
1589 add_nommu_region(new->vm_region);
1590 up_write(&nommu_region_sem);
1591 add_vma_to_mm(mm, vma);
1592 add_vma_to_mm(mm, new);
1593 return 0;
1594}
1595
1596/*
1597 * shrink a VMA by removing the specified chunk from either the beginning or
1598 * the end
1599 */
1600static int shrink_vma(struct mm_struct *mm,
1601 struct vm_area_struct *vma,
1602 unsigned long from, unsigned long to)
1603{
1604 struct vm_region *region;
1605
1606 kenter("");
1607
1608 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1609 * and list */
1610 delete_vma_from_mm(vma);
1611 if (from > vma->vm_start)
1612 vma->vm_end = from;
1613 else
1614 vma->vm_start = to;
1615 add_vma_to_mm(mm, vma);
1616
1617 /* cut the backing region down to size */
1618 region = vma->vm_region;
David Howells1e2ae592010-01-15 17:01:33 -08001619 BUG_ON(region->vm_usage != 1);
David Howells8feae132009-01-08 12:04:47 +00001620
1621 down_write(&nommu_region_sem);
1622 delete_nommu_region(region);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001623 if (from > region->vm_start) {
1624 to = region->vm_top;
1625 region->vm_top = region->vm_end = from;
1626 } else {
David Howells8feae132009-01-08 12:04:47 +00001627 region->vm_start = to;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001628 }
David Howells8feae132009-01-08 12:04:47 +00001629 add_nommu_region(region);
1630 up_write(&nommu_region_sem);
1631
1632 free_page_series(from, to);
1633 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634}
1635
David Howells30340972006-09-27 01:50:20 -07001636/*
1637 * release a mapping
David Howells8feae132009-01-08 12:04:47 +00001638 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1639 * VMA, though it need not cover the whole VMA
David Howells30340972006-09-27 01:50:20 -07001640 */
David Howells8feae132009-01-08 12:04:47 +00001641int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001642{
David Howells8feae132009-01-08 12:04:47 +00001643 struct vm_area_struct *vma;
Bob Liuf67d9b12011-05-24 17:12:56 -07001644 unsigned long end;
David Howells8feae132009-01-08 12:04:47 +00001645 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646
David Howells8feae132009-01-08 12:04:47 +00001647 kenter(",%lx,%zx", start, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648
Bob Liuf67d9b12011-05-24 17:12:56 -07001649 len = PAGE_ALIGN(len);
David Howells8feae132009-01-08 12:04:47 +00001650 if (len == 0)
1651 return -EINVAL;
1652
Bob Liuf67d9b12011-05-24 17:12:56 -07001653 end = start + len;
1654
David Howells8feae132009-01-08 12:04:47 +00001655 /* find the first potentially overlapping VMA */
1656 vma = find_vma(mm, start);
1657 if (!vma) {
David Howells33e5d7692009-04-02 16:56:32 -07001658 static int limit = 0;
1659 if (limit < 5) {
1660 printk(KERN_WARNING
1661 "munmap of memory not mmapped by process %d"
1662 " (%s): 0x%lx-0x%lx\n",
1663 current->pid, current->comm,
1664 start, start + len - 1);
1665 limit++;
1666 }
David Howells8feae132009-01-08 12:04:47 +00001667 return -EINVAL;
David Howells30340972006-09-27 01:50:20 -07001668 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669
David Howells8feae132009-01-08 12:04:47 +00001670 /* we're allowed to split an anonymous VMA but not a file-backed one */
1671 if (vma->vm_file) {
1672 do {
1673 if (start > vma->vm_start) {
1674 kleave(" = -EINVAL [miss]");
1675 return -EINVAL;
1676 }
1677 if (end == vma->vm_end)
1678 goto erase_whole_vma;
Namhyung Kimd75a3102011-05-24 17:11:25 -07001679 vma = vma->vm_next;
1680 } while (vma);
David Howells8feae132009-01-08 12:04:47 +00001681 kleave(" = -EINVAL [split file]");
1682 return -EINVAL;
1683 } else {
1684 /* the chunk must be a subset of the VMA found */
1685 if (start == vma->vm_start && end == vma->vm_end)
1686 goto erase_whole_vma;
1687 if (start < vma->vm_start || end > vma->vm_end) {
1688 kleave(" = -EINVAL [superset]");
1689 return -EINVAL;
1690 }
1691 if (start & ~PAGE_MASK) {
1692 kleave(" = -EINVAL [unaligned start]");
1693 return -EINVAL;
1694 }
1695 if (end != vma->vm_end && end & ~PAGE_MASK) {
1696 kleave(" = -EINVAL [unaligned split]");
1697 return -EINVAL;
1698 }
1699 if (start != vma->vm_start && end != vma->vm_end) {
1700 ret = split_vma(mm, vma, start, 1);
1701 if (ret < 0) {
1702 kleave(" = %d [split]", ret);
1703 return ret;
1704 }
1705 }
1706 return shrink_vma(mm, vma, start, end);
1707 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001708
David Howells8feae132009-01-08 12:04:47 +00001709erase_whole_vma:
1710 delete_vma_from_mm(vma);
1711 delete_vma(mm, vma);
1712 kleave(" = 0");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713 return 0;
1714}
Paul Mundtb5073172007-07-21 04:37:25 -07001715EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716
Al Virobfce2812012-04-20 21:57:04 -04001717int vm_munmap(unsigned long addr, size_t len)
David Howells30340972006-09-27 01:50:20 -07001718{
Al Virobfce2812012-04-20 21:57:04 -04001719 struct mm_struct *mm = current->mm;
David Howells30340972006-09-27 01:50:20 -07001720 int ret;
David Howells30340972006-09-27 01:50:20 -07001721
1722 down_write(&mm->mmap_sem);
1723 ret = do_munmap(mm, addr, len);
1724 up_write(&mm->mmap_sem);
1725 return ret;
1726}
Linus Torvaldsa46ef992012-04-20 16:20:01 -07001727EXPORT_SYMBOL(vm_munmap);
1728
1729SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1730{
Al Virobfce2812012-04-20 21:57:04 -04001731 return vm_munmap(addr, len);
Linus Torvaldsa46ef992012-04-20 16:20:01 -07001732}
David Howells30340972006-09-27 01:50:20 -07001733
1734/*
David Howells8feae132009-01-08 12:04:47 +00001735 * release all the mappings made in a process's VM space
David Howells30340972006-09-27 01:50:20 -07001736 */
David Howells8feae132009-01-08 12:04:47 +00001737void exit_mmap(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001738{
David Howells8feae132009-01-08 12:04:47 +00001739 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001740
David Howells8feae132009-01-08 12:04:47 +00001741 if (!mm)
1742 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001743
David Howells8feae132009-01-08 12:04:47 +00001744 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745
David Howells8feae132009-01-08 12:04:47 +00001746 mm->total_vm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747
David Howells8feae132009-01-08 12:04:47 +00001748 while ((vma = mm->mmap)) {
1749 mm->mmap = vma->vm_next;
1750 delete_vma_from_mm(vma);
1751 delete_vma(mm, vma);
Steven J. Magnani04c34962010-11-24 12:56:54 -08001752 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001753 }
David Howells8feae132009-01-08 12:04:47 +00001754
1755 kleave("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001756}
1757
Linus Torvaldse4eb1ff2012-04-20 15:35:40 -07001758unsigned long vm_brk(unsigned long addr, unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759{
1760 return -ENOMEM;
1761}
1762
1763/*
David Howells6fa5f802006-09-27 01:50:21 -07001764 * expand (or shrink) an existing mapping, potentially moving it at the same
1765 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766 *
David Howells6fa5f802006-09-27 01:50:21 -07001767 * under NOMMU conditions, we only permit changing a mapping's size, and only
David Howells8feae132009-01-08 12:04:47 +00001768 * as long as it stays within the region allocated by do_mmap_private() and the
1769 * block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770 *
David Howells6fa5f802006-09-27 01:50:21 -07001771 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001772 */
1773unsigned long do_mremap(unsigned long addr,
1774 unsigned long old_len, unsigned long new_len,
1775 unsigned long flags, unsigned long new_addr)
1776{
David Howells6fa5f802006-09-27 01:50:21 -07001777 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778
1779 /* insanity checks first */
Bob Liuf67d9b12011-05-24 17:12:56 -07001780 old_len = PAGE_ALIGN(old_len);
1781 new_len = PAGE_ALIGN(new_len);
David Howells8feae132009-01-08 12:04:47 +00001782 if (old_len == 0 || new_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783 return (unsigned long) -EINVAL;
1784
David Howells8feae132009-01-08 12:04:47 +00001785 if (addr & ~PAGE_MASK)
1786 return -EINVAL;
1787
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 if (flags & MREMAP_FIXED && new_addr != addr)
1789 return (unsigned long) -EINVAL;
1790
David Howells8feae132009-01-08 12:04:47 +00001791 vma = find_vma_exact(current->mm, addr, old_len);
David Howells6fa5f802006-09-27 01:50:21 -07001792 if (!vma)
1793 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001794
David Howells6fa5f802006-09-27 01:50:21 -07001795 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001796 return (unsigned long) -EFAULT;
1797
David Howells6fa5f802006-09-27 01:50:21 -07001798 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 return (unsigned long) -EPERM;
1800
David Howells8feae132009-01-08 12:04:47 +00001801 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802 return (unsigned long) -ENOMEM;
1803
1804 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001805 vma->vm_end = vma->vm_start + new_len;
David Howells6fa5f802006-09-27 01:50:21 -07001806 return vma->vm_start;
1807}
Paul Mundtb5073172007-07-21 04:37:25 -07001808EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001809
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001810SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1811 unsigned long, new_len, unsigned long, flags,
1812 unsigned long, new_addr)
David Howells6fa5f802006-09-27 01:50:21 -07001813{
1814 unsigned long ret;
1815
1816 down_write(&current->mm->mmap_sem);
1817 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1818 up_write(&current->mm->mmap_sem);
1819 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820}
1821
Michel Lespinasse240aade2013-02-22 16:35:56 -08001822struct page *follow_page_mask(struct vm_area_struct *vma,
1823 unsigned long address, unsigned int flags,
1824 unsigned int *page_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001825{
Michel Lespinasse240aade2013-02-22 16:35:56 -08001826 *page_mask = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827 return NULL;
1828}
1829
Bob Liu8f3b1322011-07-08 15:39:46 -07001830int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1831 unsigned long pfn, unsigned long size, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832{
Bob Liu8f3b1322011-07-08 15:39:46 -07001833 if (addr != (pfn << PAGE_SHIFT))
1834 return -EINVAL;
1835
Konstantin Khlebnikov314e51b2012-10-08 16:29:02 -07001836 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001837 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001838}
Luke Yang22c4af42006-07-14 00:24:09 -07001839EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840
Paul Mundtf905bc42008-02-04 22:29:59 -08001841int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1842 unsigned long pgoff)
1843{
1844 unsigned int size = vma->vm_end - vma->vm_start;
1845
1846 if (!(vma->vm_flags & VM_USERMAP))
1847 return -EINVAL;
1848
1849 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1850 vma->vm_end = vma->vm_start + size;
1851
1852 return 0;
1853}
1854EXPORT_SYMBOL(remap_vmalloc_range);
1855
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1857 unsigned long len, unsigned long pgoff, unsigned long flags)
1858{
1859 return -ENOMEM;
1860}
1861
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001862void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001863{
1864}
1865
Linus Torvalds1da177e2005-04-16 15:20:36 -07001866void unmap_mapping_range(struct address_space *mapping,
1867 loff_t const holebegin, loff_t const holelen,
1868 int even_cows)
1869{
1870}
Luke Yang22c4af42006-07-14 00:24:09 -07001871EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001872
1873/*
1874 * Check that a process has enough memory to allocate a new virtual
1875 * mapping. 0 means there is enough memory for the allocation to
1876 * succeed and -ENOMEM implies there is not.
1877 *
1878 * We currently support three overcommit policies, which are set via the
1879 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1880 *
1881 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1882 * Additional code 2002 Jul 20 by Robert Love.
1883 *
1884 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1885 *
1886 * Note this is a helper function intended to be used by LSMs which
1887 * wish to use this logic.
1888 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001889int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890{
1891 unsigned long free, allowed;
1892
1893 vm_acct_memory(pages);
1894
1895 /*
1896 * Sometimes we want to use more memory than we have
1897 */
1898 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1899 return 0;
1900
1901 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
Dmitry Finkc15bef32011-07-25 17:12:19 -07001902 free = global_page_state(NR_FREE_PAGES);
1903 free += global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001904
Dmitry Finkc15bef32011-07-25 17:12:19 -07001905 /*
1906 * shmem pages shouldn't be counted as free in this
1907 * case, they can't be purged, only swapped out, and
1908 * that won't affect the overall amount of available
1909 * memory in the system.
1910 */
1911 free -= global_page_state(NR_SHMEM);
1912
Shaohua Liec8acf22013-02-22 16:34:38 -08001913 free += get_nr_swap_pages();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914
1915 /*
1916 * Any slabs which are created with the
1917 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1918 * which are reclaimable, under pressure. The dentry
1919 * cache and most inode caches should fall into this
1920 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001921 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922
1923 /*
Dmitry Finkc15bef32011-07-25 17:12:19 -07001924 * Leave reserved pages. The pages are not for anonymous pages.
1925 */
1926 if (free <= totalreserve_pages)
1927 goto error;
1928 else
1929 free -= totalreserve_pages;
1930
1931 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932 * Leave the last 3% for root
1933 */
1934 if (!cap_sys_admin)
1935 free -= free / 32;
1936
1937 if (free > pages)
1938 return 0;
1939
Hideo AOKId5ddc792006-04-10 22:53:01 -07001940 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001941 }
1942
1943 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1944 /*
1945 * Leave the last 3% for root
1946 */
1947 if (!cap_sys_admin)
1948 allowed -= allowed / 32;
1949 allowed += total_swap_pages;
1950
1951 /* Don't let a single process grow too big:
1952 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -07001953 if (mm)
1954 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001956 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957 return 0;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001958
Hideo AOKId5ddc792006-04-10 22:53:01 -07001959error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001960 vm_unacct_memory(pages);
1961
1962 return -ENOMEM;
1963}
1964
Stephen Wilsoncae5d392011-03-13 15:49:17 -04001965int in_gate_area_no_mm(unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966{
1967 return 0;
1968}
David Howellsb0e15192006-01-06 00:11:42 -08001969
Nick Piggind0217ac2007-07-19 01:47:03 -07001970int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001971{
1972 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001973 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001974}
Paul Mundtb5073172007-07-21 04:37:25 -07001975EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001976
Konstantin Khlebnikov0b173bc2012-10-08 16:28:46 -07001977int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
1978 unsigned long size, pgoff_t pgoff)
1979{
1980 BUG();
1981 return 0;
1982}
1983EXPORT_SYMBOL(generic_file_remap_pages);
1984
Mike Frysingerf55f1992011-03-29 14:05:12 +01001985static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1986 unsigned long addr, void *buf, int len, int write)
David Howells0ec76a12006-09-27 01:50:15 -07001987{
David Howells0ec76a12006-09-27 01:50:15 -07001988 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07001989
1990 down_read(&mm->mmap_sem);
1991
1992 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001993 vma = find_vma(mm, addr);
1994 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001995 /* don't overrun this mapping */
1996 if (addr + len >= vma->vm_end)
1997 len = vma->vm_end - addr;
1998
1999 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07002000 if (write && vma->vm_flags & VM_MAYWRITE)
Jie Zhang79597222010-01-06 17:23:28 +00002001 copy_to_user_page(vma, NULL, addr,
2002 (void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07002003 else if (!write && vma->vm_flags & VM_MAYREAD)
Jie Zhang79597222010-01-06 17:23:28 +00002004 copy_from_user_page(vma, NULL, addr,
2005 buf, (void *) addr, len);
David Howells0ec76a12006-09-27 01:50:15 -07002006 else
2007 len = 0;
2008 } else {
2009 len = 0;
2010 }
2011
2012 up_read(&mm->mmap_sem);
Mike Frysingerf55f1992011-03-29 14:05:12 +01002013
2014 return len;
2015}
2016
2017/**
2018 * @access_remote_vm - access another process' address space
2019 * @mm: the mm_struct of the target address space
2020 * @addr: start address to access
2021 * @buf: source or destination buffer
2022 * @len: number of bytes to transfer
2023 * @write: whether the access is a write
2024 *
2025 * The caller must hold a reference on @mm.
2026 */
2027int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2028 void *buf, int len, int write)
2029{
2030 return __access_remote_vm(NULL, mm, addr, buf, len, write);
2031}
2032
2033/*
2034 * Access another process' address space.
2035 * - source/target buffer must be kernel space
2036 */
2037int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2038{
2039 struct mm_struct *mm;
2040
2041 if (addr + len < addr)
2042 return 0;
2043
2044 mm = get_task_mm(tsk);
2045 if (!mm)
2046 return 0;
2047
2048 len = __access_remote_vm(tsk, mm, addr, buf, len, write);
2049
David Howells0ec76a12006-09-27 01:50:15 -07002050 mmput(mm);
2051 return len;
2052}
David Howells7e660872010-01-15 17:01:39 -08002053
2054/**
2055 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
2056 * @inode: The inode to check
2057 * @size: The current filesize of the inode
2058 * @newsize: The proposed filesize of the inode
2059 *
2060 * Check the shared mappings on an inode on behalf of a shrinking truncate to
2061 * make sure that that any outstanding VMAs aren't broken and then shrink the
2062 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
2063 * automatically grant mappings that are too large.
2064 */
2065int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
2066 size_t newsize)
2067{
2068 struct vm_area_struct *vma;
David Howells7e660872010-01-15 17:01:39 -08002069 struct vm_region *region;
2070 pgoff_t low, high;
2071 size_t r_size, r_top;
2072
2073 low = newsize >> PAGE_SHIFT;
2074 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2075
2076 down_write(&nommu_region_sem);
David Howells918e5562012-02-23 13:50:35 +00002077 mutex_lock(&inode->i_mapping->i_mmap_mutex);
David Howells7e660872010-01-15 17:01:39 -08002078
2079 /* search for VMAs that fall within the dead zone */
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -07002080 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
David Howells7e660872010-01-15 17:01:39 -08002081 /* found one - only interested if it's shared out of the page
2082 * cache */
2083 if (vma->vm_flags & VM_SHARED) {
David Howells918e5562012-02-23 13:50:35 +00002084 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
David Howells7e660872010-01-15 17:01:39 -08002085 up_write(&nommu_region_sem);
2086 return -ETXTBSY; /* not quite true, but near enough */
2087 }
2088 }
2089
2090 /* reduce any regions that overlap the dead zone - if in existence,
2091 * these will be pointed to by VMAs that don't overlap the dead zone
2092 *
2093 * we don't check for any regions that start beyond the EOF as there
2094 * shouldn't be any
2095 */
Michel Lespinasse6b2dbba2012-10-08 16:31:25 -07002096 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap,
2097 0, ULONG_MAX) {
David Howells7e660872010-01-15 17:01:39 -08002098 if (!(vma->vm_flags & VM_SHARED))
2099 continue;
2100
2101 region = vma->vm_region;
2102 r_size = region->vm_top - region->vm_start;
2103 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
2104
2105 if (r_top > newsize) {
2106 region->vm_top -= r_top - newsize;
2107 if (region->vm_end > region->vm_top)
2108 region->vm_end = region->vm_top;
2109 }
2110 }
2111
David Howells918e5562012-02-23 13:50:35 +00002112 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
David Howells7e660872010-01-15 17:01:39 -08002113 up_write(&nommu_region_sem);
2114 return 0;
2115}