blob: 66e81e7e9fe98f6871cb0d159e13c6942ff8e44f [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 Mundteb6434d2009-01-21 17:45:47 +090013 * Copyright (c) 2007-2009 Paul Mundt <lethal@linux-sh.org>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 */
15
David Howellsf2b85442007-10-29 13:15:39 +000016#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/mm.h>
18#include <linux/mman.h>
19#include <linux/swap.h>
20#include <linux/file.h>
21#include <linux/highmem.h>
22#include <linux/pagemap.h>
23#include <linux/slab.h>
24#include <linux/vmalloc.h>
Roland McGrathfa8e26c2008-07-25 19:45:50 -070025#include <linux/tracehook.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070026#include <linux/blkdev.h>
27#include <linux/backing-dev.h>
28#include <linux/mount.h>
29#include <linux/personality.h>
30#include <linux/security.h>
31#include <linux/syscalls.h>
32
33#include <asm/uaccess.h>
34#include <asm/tlb.h>
35#include <asm/tlbflush.h>
David Howells8feae132009-01-08 12:04:47 +000036#include "internal.h"
37
38static inline __attribute__((format(printf, 1, 2)))
39void no_printk(const char *fmt, ...)
40{
41}
42
43#if 0
44#define kenter(FMT, ...) \
45 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
46#define kleave(FMT, ...) \
47 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
48#define kdebug(FMT, ...) \
49 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
50#else
51#define kenter(FMT, ...) \
52 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
53#define kleave(FMT, ...) \
54 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
55#define kdebug(FMT, ...) \
56 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
57#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Nick Pigginb291f002008-10-18 20:26:44 -070059#include "internal.h"
60
Linus Torvalds1da177e2005-04-16 15:20:36 -070061void *high_memory;
62struct page *mem_map;
63unsigned long max_mapnr;
64unsigned long num_physpages;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -070065struct percpu_counter vm_committed_as;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
67int sysctl_overcommit_ratio = 50; /* default is 50% */
68int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
David Howellsfc4d5c22009-05-06 16:03:05 -070069int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070int heap_stack_gap = 0;
71
David Howells33e5d7692009-04-02 16:56:32 -070072atomic_long_t mmap_pages_allocated;
David Howells8feae132009-01-08 12:04:47 +000073
Linus Torvalds1da177e2005-04-16 15:20:36 -070074EXPORT_SYMBOL(mem_map);
Wu, Bryan6a04de62007-04-11 23:28:47 -070075EXPORT_SYMBOL(num_physpages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
David Howells8feae132009-01-08 12:04:47 +000077/* list of mapped, potentially shareable regions */
78static struct kmem_cache *vm_region_jar;
79struct rb_root nommu_region_tree = RB_ROOT;
80DECLARE_RWSEM(nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -070081
82struct vm_operations_struct generic_file_vm_ops = {
83};
84
85/*
86 * Handle all mappings that got truncated by a "truncate()"
87 * system call.
88 *
89 * NOTE! We have to be ready to update the memory sharing
90 * between the file and the memory map for a potential last
91 * incomplete page. Ugly, but necessary.
92 */
93int vmtruncate(struct inode *inode, loff_t offset)
94{
95 struct address_space *mapping = inode->i_mapping;
96 unsigned long limit;
97
98 if (inode->i_size < offset)
99 goto do_expand;
100 i_size_write(inode, offset);
101
102 truncate_inode_pages(mapping, offset);
103 goto out_truncate;
104
105do_expand:
106 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
107 if (limit != RLIM_INFINITY && offset > limit)
108 goto out_sig;
109 if (offset > inode->i_sb->s_maxbytes)
110 goto out;
111 i_size_write(inode, offset);
112
113out_truncate:
Al Viroacfa4382008-12-04 10:06:33 -0500114 if (inode->i_op->truncate)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115 inode->i_op->truncate(inode);
116 return 0;
117out_sig:
118 send_sig(SIGXFSZ, current, 0);
119out:
120 return -EFBIG;
121}
122
123EXPORT_SYMBOL(vmtruncate);
124
125/*
126 * Return the total memory allocated for this pointer, not
127 * just what the caller asked for.
128 *
129 * Doesn't have to be accurate, i.e. may have races.
130 */
131unsigned int kobjsize(const void *objp)
132{
133 struct page *page;
134
Michael Hennerich4016a132008-04-28 02:13:38 -0700135 /*
136 * If the object we have should not have ksize performed on it,
137 * return size of 0
138 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900139 if (!objp || !virt_addr_valid(objp))
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700140 return 0;
141
142 page = virt_to_head_page(objp);
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700143
144 /*
145 * If the allocator sets PageSlab, we know the pointer came from
146 * kmalloc().
147 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 if (PageSlab(page))
149 return ksize(objp);
150
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700151 /*
Paul Mundtab2e83e2009-01-08 12:04:48 +0000152 * If it's not a compound page, see if we have a matching VMA
153 * region. This test is intentionally done in reverse order,
154 * so if there's no VMA, we still fall through and hand back
155 * PAGE_SIZE for 0-order pages.
156 */
157 if (!PageCompound(page)) {
158 struct vm_area_struct *vma;
159
160 vma = find_vma(current->mm, (unsigned long)objp);
161 if (vma)
162 return vma->vm_end - vma->vm_start;
163 }
164
165 /*
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700166 * The ksize() function is only guaranteed to work for pointers
Paul Mundt5a1603b2008-06-12 16:29:55 +0900167 * returned by kmalloc(). So handle arbitrary pointers here.
Paul Mundt6cfd53fc2008-06-05 22:46:08 -0700168 */
Paul Mundt5a1603b2008-06-12 16:29:55 +0900169 return PAGE_SIZE << compound_order(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170}
171
Nick Pigginb291f002008-10-18 20:26:44 -0700172int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Peter Zijlstra9d737772009-06-25 11:58:55 +0200173 unsigned long start, int nr_pages, int flags,
174 struct page **pages, struct vm_area_struct **vmas)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175{
Sonic Zhang910e46d2006-09-27 01:50:17 -0700176 struct vm_area_struct *vma;
David Howells7b4d5b82006-09-27 01:50:18 -0700177 unsigned long vm_flags;
178 int i;
Nick Pigginb291f002008-10-18 20:26:44 -0700179 int write = !!(flags & GUP_FLAGS_WRITE);
180 int force = !!(flags & GUP_FLAGS_FORCE);
181 int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS);
David Howells7b4d5b82006-09-27 01:50:18 -0700182
183 /* calculate required read or write permissions.
184 * - if 'force' is set, we only require the "MAY" flags.
185 */
186 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
187 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188
Peter Zijlstra9d737772009-06-25 11:58:55 +0200189 for (i = 0; i < nr_pages; i++) {
Sonic Zhang910e46d2006-09-27 01:50:17 -0700190 vma = find_vma(mm, start);
David Howells7b4d5b82006-09-27 01:50:18 -0700191 if (!vma)
192 goto finish_or_fault;
193
194 /* protect what we can, including chardevs */
195 if (vma->vm_flags & (VM_IO | VM_PFNMAP) ||
Nick Pigginb291f002008-10-18 20:26:44 -0700196 (!ignore && !(vm_flags & vma->vm_flags)))
David Howells7b4d5b82006-09-27 01:50:18 -0700197 goto finish_or_fault;
Sonic Zhang910e46d2006-09-27 01:50:17 -0700198
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 if (pages) {
200 pages[i] = virt_to_page(start);
201 if (pages[i])
202 page_cache_get(pages[i]);
203 }
204 if (vmas)
Sonic Zhang910e46d2006-09-27 01:50:17 -0700205 vmas[i] = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 start += PAGE_SIZE;
207 }
David Howells7b4d5b82006-09-27 01:50:18 -0700208
209 return i;
210
211finish_or_fault:
212 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213}
Nick Pigginb291f002008-10-18 20:26:44 -0700214
215
216/*
217 * get a list of pages in an address range belonging to the specified process
218 * and indicate the VMA that covers each page
219 * - this is potentially dodgy as we may end incrementing the page count of a
220 * slab page or a secondary page from a compound page
221 * - don't permit access to VMAs that don't support it, such as I/O mappings
222 */
223int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Peter Zijlstra9d737772009-06-25 11:58:55 +0200224 unsigned long start, int nr_pages, int write, int force,
Nick Pigginb291f002008-10-18 20:26:44 -0700225 struct page **pages, struct vm_area_struct **vmas)
226{
227 int flags = 0;
228
229 if (write)
230 flags |= GUP_FLAGS_WRITE;
231 if (force)
232 flags |= GUP_FLAGS_FORCE;
233
Peter Zijlstra9d737772009-06-25 11:58:55 +0200234 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
Nick Pigginb291f002008-10-18 20:26:44 -0700235}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000236EXPORT_SYMBOL(get_user_pages);
237
Paul Mundtdfc2f912009-06-26 04:31:57 +0900238/**
239 * follow_pfn - look up PFN at a user virtual address
240 * @vma: memory mapping
241 * @address: user virtual address
242 * @pfn: location to store found PFN
243 *
244 * Only IO mappings and raw PFN mappings are allowed.
245 *
246 * Returns zero and the pfn at @pfn on success, -ve otherwise.
247 */
248int follow_pfn(struct vm_area_struct *vma, unsigned long address,
249 unsigned long *pfn)
250{
251 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
252 return -EINVAL;
253
254 *pfn = address >> PAGE_SHIFT;
255 return 0;
256}
257EXPORT_SYMBOL(follow_pfn);
258
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259DEFINE_RWLOCK(vmlist_lock);
260struct vm_struct *vmlist;
261
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800262void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263{
264 kfree(addr);
265}
Paul Mundtb5073172007-07-21 04:37:25 -0700266EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267
Al Virodd0fc662005-10-07 07:46:04 +0100268void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269{
270 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200271 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
272 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 */
Nick Piggin84097512006-03-22 00:08:34 -0800274 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275}
Paul Mundtb5073172007-07-21 04:37:25 -0700276EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277
Paul Mundtf905bc42008-02-04 22:29:59 -0800278void *vmalloc_user(unsigned long size)
279{
280 void *ret;
281
282 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
283 PAGE_KERNEL);
284 if (ret) {
285 struct vm_area_struct *vma;
286
287 down_write(&current->mm->mmap_sem);
288 vma = find_vma(current->mm, (unsigned long)ret);
289 if (vma)
290 vma->vm_flags |= VM_USERMAP;
291 up_write(&current->mm->mmap_sem);
292 }
293
294 return ret;
295}
296EXPORT_SYMBOL(vmalloc_user);
297
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800298struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299{
300 return virt_to_page(addr);
301}
Paul Mundtb5073172007-07-21 04:37:25 -0700302EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800304unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305{
306 return page_to_pfn(virt_to_page(addr));
307}
Paul Mundtb5073172007-07-21 04:37:25 -0700308EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309
310long vread(char *buf, char *addr, unsigned long count)
311{
312 memcpy(buf, addr, count);
313 return count;
314}
315
316long vwrite(char *buf, char *addr, unsigned long count)
317{
318 /* Don't allow overflow */
319 if ((unsigned long) addr + count < count)
320 count = -(unsigned long) addr;
321
322 memcpy(addr, buf, count);
323 return(count);
324}
325
326/*
327 * vmalloc - allocate virtually continguos memory
328 *
329 * @size: allocation size
330 *
331 * Allocate enough pages to cover @size from the page level
332 * allocator and map them into continguos kernel virtual space.
333 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200334 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 * use __vmalloc() instead.
336 */
337void *vmalloc(unsigned long size)
338{
339 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
340}
Andrew Mortonf6138882006-02-28 16:59:18 -0800341EXPORT_SYMBOL(vmalloc);
342
343void *vmalloc_node(unsigned long size, int node)
344{
345 return vmalloc(size);
346}
347EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
Paul Mundt1af446e2008-08-04 16:01:47 +0900349#ifndef PAGE_KERNEL_EXEC
350# define PAGE_KERNEL_EXEC PAGE_KERNEL
351#endif
352
353/**
354 * vmalloc_exec - allocate virtually contiguous, executable memory
355 * @size: allocation size
356 *
357 * Kernel-internal function to allocate enough pages to cover @size
358 * the page level allocator and map them into contiguous and
359 * executable kernel virtual space.
360 *
361 * For tight control over page level allocator and protection flags
362 * use __vmalloc() instead.
363 */
364
365void *vmalloc_exec(unsigned long size)
366{
367 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
368}
369
Paul Mundtb5073172007-07-21 04:37:25 -0700370/**
371 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 * @size: allocation size
373 *
374 * Allocate enough 32bit PA addressable pages to cover @size from the
375 * page level allocator and map them into continguos kernel virtual space.
376 */
377void *vmalloc_32(unsigned long size)
378{
379 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
380}
Paul Mundtb5073172007-07-21 04:37:25 -0700381EXPORT_SYMBOL(vmalloc_32);
382
383/**
384 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
385 * @size: allocation size
386 *
387 * The resulting memory area is 32bit addressable and zeroed so it can be
388 * mapped to userspace without leaking data.
Paul Mundtf905bc42008-02-04 22:29:59 -0800389 *
390 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
391 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700392 */
393void *vmalloc_32_user(unsigned long size)
394{
Paul Mundtf905bc42008-02-04 22:29:59 -0800395 /*
396 * We'll have to sort out the ZONE_DMA bits for 64-bit,
397 * but for now this can simply use vmalloc_user() directly.
398 */
399 return vmalloc_user(size);
Paul Mundtb5073172007-07-21 04:37:25 -0700400}
401EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402
403void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
404{
405 BUG();
406 return NULL;
407}
Paul Mundtb5073172007-07-21 04:37:25 -0700408EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800410void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411{
412 BUG();
413}
Paul Mundtb5073172007-07-21 04:37:25 -0700414EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415
Paul Mundteb6434d2009-01-21 17:45:47 +0900416void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
417{
418 BUG();
419 return NULL;
420}
421EXPORT_SYMBOL(vm_map_ram);
422
423void vm_unmap_ram(const void *mem, unsigned int count)
424{
425 BUG();
426}
427EXPORT_SYMBOL(vm_unmap_ram);
428
429void vm_unmap_aliases(void)
430{
431}
432EXPORT_SYMBOL_GPL(vm_unmap_aliases);
433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700435 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
436 * have one.
437 */
438void __attribute__((weak)) vmalloc_sync_all(void)
439{
440}
441
Paul Mundtb5073172007-07-21 04:37:25 -0700442int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
443 struct page *page)
444{
445 return -EINVAL;
446}
447EXPORT_SYMBOL(vm_insert_page);
448
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700449/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 * sys_brk() for the most part doesn't need the global kernel
451 * lock, except when an application is doing something nasty
452 * like trying to un-brk an area that has already been mapped
453 * to a regular file. in this case, the unmapping will need
454 * to invoke file system routines that need the global lock.
455 */
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100456SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700457{
458 struct mm_struct *mm = current->mm;
459
460 if (brk < mm->start_brk || brk > mm->context.end_brk)
461 return mm->brk;
462
463 if (mm->brk == brk)
464 return mm->brk;
465
466 /*
467 * Always allow shrinking brk
468 */
469 if (brk <= mm->brk) {
470 mm->brk = brk;
471 return brk;
472 }
473
474 /*
475 * Ok, looks good - let it rip.
476 */
477 return mm->brk = brk;
478}
479
David Howells8feae132009-01-08 12:04:47 +0000480/*
481 * initialise the VMA and region record slabs
482 */
483void __init mmap_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484{
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -0700485 int ret;
486
487 ret = percpu_counter_init(&vm_committed_as, 0);
488 VM_BUG_ON(ret);
David Howells33e5d7692009-04-02 16:56:32 -0700489 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
David Howells8feae132009-01-08 12:04:47 +0000490}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491
David Howells8feae132009-01-08 12:04:47 +0000492/*
493 * validate the region tree
494 * - the caller must hold the region lock
495 */
496#ifdef CONFIG_DEBUG_NOMMU_REGIONS
497static noinline void validate_nommu_regions(void)
498{
499 struct vm_region *region, *last;
500 struct rb_node *p, *lastp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501
David Howells8feae132009-01-08 12:04:47 +0000502 lastp = rb_first(&nommu_region_tree);
503 if (!lastp)
504 return;
505
506 last = rb_entry(lastp, struct vm_region, vm_rb);
David Howells33e5d7692009-04-02 16:56:32 -0700507 BUG_ON(unlikely(last->vm_end <= last->vm_start));
508 BUG_ON(unlikely(last->vm_top < last->vm_end));
David Howells8feae132009-01-08 12:04:47 +0000509
510 while ((p = rb_next(lastp))) {
511 region = rb_entry(p, struct vm_region, vm_rb);
512 last = rb_entry(lastp, struct vm_region, vm_rb);
513
David Howells33e5d7692009-04-02 16:56:32 -0700514 BUG_ON(unlikely(region->vm_end <= region->vm_start));
515 BUG_ON(unlikely(region->vm_top < region->vm_end));
516 BUG_ON(unlikely(region->vm_start < last->vm_top));
David Howells8feae132009-01-08 12:04:47 +0000517
518 lastp = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 }
520}
David Howells8feae132009-01-08 12:04:47 +0000521#else
David Howells33e5d7692009-04-02 16:56:32 -0700522static void validate_nommu_regions(void)
523{
524}
David Howells8feae132009-01-08 12:04:47 +0000525#endif
526
527/*
528 * add a region into the global tree
529 */
530static void add_nommu_region(struct vm_region *region)
531{
532 struct vm_region *pregion;
533 struct rb_node **p, *parent;
534
535 validate_nommu_regions();
536
David Howells8feae132009-01-08 12:04:47 +0000537 parent = NULL;
538 p = &nommu_region_tree.rb_node;
539 while (*p) {
540 parent = *p;
541 pregion = rb_entry(parent, struct vm_region, vm_rb);
542 if (region->vm_start < pregion->vm_start)
543 p = &(*p)->rb_left;
544 else if (region->vm_start > pregion->vm_start)
545 p = &(*p)->rb_right;
546 else if (pregion == region)
547 return;
548 else
549 BUG();
550 }
551
552 rb_link_node(&region->vm_rb, parent, p);
553 rb_insert_color(&region->vm_rb, &nommu_region_tree);
554
555 validate_nommu_regions();
556}
557
558/*
559 * delete a region from the global tree
560 */
561static void delete_nommu_region(struct vm_region *region)
562{
563 BUG_ON(!nommu_region_tree.rb_node);
564
565 validate_nommu_regions();
566 rb_erase(&region->vm_rb, &nommu_region_tree);
567 validate_nommu_regions();
568}
569
570/*
571 * free a contiguous series of pages
572 */
573static void free_page_series(unsigned long from, unsigned long to)
574{
575 for (; from < to; from += PAGE_SIZE) {
576 struct page *page = virt_to_page(from);
577
578 kdebug("- free %lx", from);
David Howells33e5d7692009-04-02 16:56:32 -0700579 atomic_long_dec(&mmap_pages_allocated);
David Howells8feae132009-01-08 12:04:47 +0000580 if (page_count(page) != 1)
David Howells33e5d7692009-04-02 16:56:32 -0700581 kdebug("free page %p: refcount not one: %d",
582 page, page_count(page));
David Howells8feae132009-01-08 12:04:47 +0000583 put_page(page);
584 }
585}
586
587/*
588 * release a reference to a region
David Howells33e5d7692009-04-02 16:56:32 -0700589 * - the caller must hold the region semaphore for writing, which this releases
Paul Mundtdd8632a2009-01-08 12:04:47 +0000590 * - the region may not have been added to the tree yet, in which case vm_top
David Howells8feae132009-01-08 12:04:47 +0000591 * will equal vm_start
592 */
593static void __put_nommu_region(struct vm_region *region)
594 __releases(nommu_region_sem)
595{
596 kenter("%p{%d}", region, atomic_read(&region->vm_usage));
597
598 BUG_ON(!nommu_region_tree.rb_node);
599
600 if (atomic_dec_and_test(&region->vm_usage)) {
Paul Mundtdd8632a2009-01-08 12:04:47 +0000601 if (region->vm_top > region->vm_start)
David Howells8feae132009-01-08 12:04:47 +0000602 delete_nommu_region(region);
603 up_write(&nommu_region_sem);
604
605 if (region->vm_file)
606 fput(region->vm_file);
607
608 /* IO memory and memory shared directly out of the pagecache
609 * from ramfs/tmpfs mustn't be released here */
610 if (region->vm_flags & VM_MAPPED_COPY) {
611 kdebug("free series");
Paul Mundtdd8632a2009-01-08 12:04:47 +0000612 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +0000613 }
614 kmem_cache_free(vm_region_jar, region);
615 } else {
616 up_write(&nommu_region_sem);
617 }
618}
619
620/*
621 * release a reference to a region
622 */
623static void put_nommu_region(struct vm_region *region)
624{
625 down_write(&nommu_region_sem);
626 __put_nommu_region(region);
627}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628
David Howells30340972006-09-27 01:50:20 -0700629/*
630 * add a VMA into a process's mm_struct in the appropriate place in the list
David Howells8feae132009-01-08 12:04:47 +0000631 * and tree and add to the address space's page tree also if not an anonymous
632 * page
David Howells30340972006-09-27 01:50:20 -0700633 * - should be called with mm->mmap_sem held writelocked
634 */
David Howells8feae132009-01-08 12:04:47 +0000635static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
David Howells30340972006-09-27 01:50:20 -0700636{
David Howells8feae132009-01-08 12:04:47 +0000637 struct vm_area_struct *pvma, **pp;
638 struct address_space *mapping;
639 struct rb_node **p, *parent;
David Howells30340972006-09-27 01:50:20 -0700640
David Howells8feae132009-01-08 12:04:47 +0000641 kenter(",%p", vma);
642
643 BUG_ON(!vma->vm_region);
644
645 mm->map_count++;
646 vma->vm_mm = mm;
647
648 /* add the VMA to the mapping */
649 if (vma->vm_file) {
650 mapping = vma->vm_file->f_mapping;
651
652 flush_dcache_mmap_lock(mapping);
653 vma_prio_tree_insert(vma, &mapping->i_mmap);
654 flush_dcache_mmap_unlock(mapping);
655 }
656
657 /* add the VMA to the tree */
658 parent = NULL;
659 p = &mm->mm_rb.rb_node;
660 while (*p) {
661 parent = *p;
662 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
663
664 /* sort by: start addr, end addr, VMA struct addr in that order
665 * (the latter is necessary as we may get identical VMAs) */
666 if (vma->vm_start < pvma->vm_start)
667 p = &(*p)->rb_left;
668 else if (vma->vm_start > pvma->vm_start)
669 p = &(*p)->rb_right;
670 else if (vma->vm_end < pvma->vm_end)
671 p = &(*p)->rb_left;
672 else if (vma->vm_end > pvma->vm_end)
673 p = &(*p)->rb_right;
674 else if (vma < pvma)
675 p = &(*p)->rb_left;
676 else if (vma > pvma)
677 p = &(*p)->rb_right;
678 else
679 BUG();
680 }
681
682 rb_link_node(&vma->vm_rb, parent, p);
683 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
684
685 /* add VMA to the VMA list also */
686 for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
687 if (pvma->vm_start > vma->vm_start)
David Howells30340972006-09-27 01:50:20 -0700688 break;
David Howells8feae132009-01-08 12:04:47 +0000689 if (pvma->vm_start < vma->vm_start)
690 continue;
691 if (pvma->vm_end < vma->vm_end)
692 break;
693 }
David Howells30340972006-09-27 01:50:20 -0700694
David Howells8feae132009-01-08 12:04:47 +0000695 vma->vm_next = *pp;
696 *pp = vma;
697}
698
699/*
700 * delete a VMA from its owning mm_struct and address space
701 */
702static void delete_vma_from_mm(struct vm_area_struct *vma)
703{
704 struct vm_area_struct **pp;
705 struct address_space *mapping;
706 struct mm_struct *mm = vma->vm_mm;
707
708 kenter("%p", vma);
709
710 mm->map_count--;
711 if (mm->mmap_cache == vma)
712 mm->mmap_cache = NULL;
713
714 /* remove the VMA from the mapping */
715 if (vma->vm_file) {
716 mapping = vma->vm_file->f_mapping;
717
718 flush_dcache_mmap_lock(mapping);
719 vma_prio_tree_remove(vma, &mapping->i_mmap);
720 flush_dcache_mmap_unlock(mapping);
721 }
722
723 /* remove from the MM's tree and list */
724 rb_erase(&vma->vm_rb, &mm->mm_rb);
725 for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
726 if (*pp == vma) {
727 *pp = vma->vm_next;
728 break;
729 }
730 }
731
732 vma->vm_mm = NULL;
733}
734
735/*
736 * destroy a VMA record
737 */
738static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
739{
740 kenter("%p", vma);
741 if (vma->vm_ops && vma->vm_ops->close)
742 vma->vm_ops->close(vma);
743 if (vma->vm_file) {
744 fput(vma->vm_file);
745 if (vma->vm_flags & VM_EXECUTABLE)
746 removed_exe_file_vma(mm);
747 }
748 put_nommu_region(vma->vm_region);
749 kmem_cache_free(vm_area_cachep, vma);
David Howells30340972006-09-27 01:50:20 -0700750}
751
752/*
753 * look up the first VMA in which addr resides, NULL if none
754 * - should be called with mm->mmap_sem at least held readlocked
755 */
756struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
757{
David Howells8feae132009-01-08 12:04:47 +0000758 struct vm_area_struct *vma;
759 struct rb_node *n = mm->mm_rb.rb_node;
David Howells30340972006-09-27 01:50:20 -0700760
David Howells8feae132009-01-08 12:04:47 +0000761 /* check the cache first */
762 vma = mm->mmap_cache;
763 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
764 return vma;
765
766 /* trawl the tree (there may be multiple mappings in which addr
767 * resides) */
768 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
769 vma = rb_entry(n, struct vm_area_struct, vm_rb);
770 if (vma->vm_start > addr)
771 return NULL;
772 if (vma->vm_end > addr) {
773 mm->mmap_cache = vma;
774 return vma;
775 }
David Howells30340972006-09-27 01:50:20 -0700776 }
777
David Howells30340972006-09-27 01:50:20 -0700778 return NULL;
779}
780EXPORT_SYMBOL(find_vma);
781
782/*
David Howells930e6522006-09-27 01:50:22 -0700783 * find a VMA
784 * - we don't extend stack VMAs under NOMMU conditions
785 */
786struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
787{
788 return find_vma(mm, addr);
789}
790
David Howells8feae132009-01-08 12:04:47 +0000791/*
792 * expand a stack to a given address
793 * - not supported under NOMMU conditions
794 */
Greg Ungerer57c8f632007-07-15 23:38:28 -0700795int expand_stack(struct vm_area_struct *vma, unsigned long address)
796{
797 return -ENOMEM;
798}
799
David Howells930e6522006-09-27 01:50:22 -0700800/*
David Howells6fa5f802006-09-27 01:50:21 -0700801 * look up the first VMA exactly that exactly matches addr
802 * - should be called with mm->mmap_sem at least held readlocked
803 */
David Howells8feae132009-01-08 12:04:47 +0000804static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
805 unsigned long addr,
806 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807{
808 struct vm_area_struct *vma;
David Howells8feae132009-01-08 12:04:47 +0000809 struct rb_node *n = mm->mm_rb.rb_node;
810 unsigned long end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811
David Howells8feae132009-01-08 12:04:47 +0000812 /* check the cache first */
813 vma = mm->mmap_cache;
814 if (vma && vma->vm_start == addr && vma->vm_end == end)
815 return vma;
816
817 /* trawl the tree (there may be multiple mappings in which addr
818 * resides) */
819 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 vma = rb_entry(n, struct vm_area_struct, vm_rb);
David Howells8feae132009-01-08 12:04:47 +0000821 if (vma->vm_start < addr)
822 continue;
823 if (vma->vm_start > addr)
824 return NULL;
825 if (vma->vm_end == end) {
826 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 return vma;
David Howells8feae132009-01-08 12:04:47 +0000828 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 }
830
831 return NULL;
832}
833
David Howells30340972006-09-27 01:50:20 -0700834/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 * determine whether a mapping should be permitted and, if so, what sort of
836 * mapping we're capable of supporting
837 */
838static int validate_mmap_request(struct file *file,
839 unsigned long addr,
840 unsigned long len,
841 unsigned long prot,
842 unsigned long flags,
843 unsigned long pgoff,
844 unsigned long *_capabilities)
845{
David Howells8feae132009-01-08 12:04:47 +0000846 unsigned long capabilities, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 unsigned long reqprot = prot;
848 int ret;
849
850 /* do the simple checks first */
851 if (flags & MAP_FIXED || addr) {
852 printk(KERN_DEBUG
853 "%d: Can't do fixed-address/overlay mmap of RAM\n",
854 current->pid);
855 return -EINVAL;
856 }
857
858 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
859 (flags & MAP_TYPE) != MAP_SHARED)
860 return -EINVAL;
861
Mike Frysingerf81cff02006-12-06 12:02:59 +1000862 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 return -EINVAL;
864
Mike Frysingerf81cff02006-12-06 12:02:59 +1000865 /* Careful about overflows.. */
David Howells8feae132009-01-08 12:04:47 +0000866 rlen = PAGE_ALIGN(len);
867 if (!rlen || rlen > TASK_SIZE)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000868 return -ENOMEM;
869
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870 /* offset overflow? */
David Howells8feae132009-01-08 12:04:47 +0000871 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000872 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873
874 if (file) {
875 /* validate file mapping requests */
876 struct address_space *mapping;
877
878 /* files must support mmap */
879 if (!file->f_op || !file->f_op->mmap)
880 return -ENODEV;
881
882 /* work out if what we've got could possibly be shared
883 * - we support chardevs that provide their own "memory"
884 * - we support files/blockdevs that are memory backed
885 */
886 mapping = file->f_mapping;
887 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800888 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889
890 capabilities = 0;
891 if (mapping && mapping->backing_dev_info)
892 capabilities = mapping->backing_dev_info->capabilities;
893
894 if (!capabilities) {
895 /* no explicit capabilities set, so assume some
896 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800897 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 case S_IFREG:
899 case S_IFBLK:
900 capabilities = BDI_CAP_MAP_COPY;
901 break;
902
903 case S_IFCHR:
904 capabilities =
905 BDI_CAP_MAP_DIRECT |
906 BDI_CAP_READ_MAP |
907 BDI_CAP_WRITE_MAP;
908 break;
909
910 default:
911 return -EINVAL;
912 }
913 }
914
915 /* eliminate any capabilities that we can't support on this
916 * device */
917 if (!file->f_op->get_unmapped_area)
918 capabilities &= ~BDI_CAP_MAP_DIRECT;
919 if (!file->f_op->read)
920 capabilities &= ~BDI_CAP_MAP_COPY;
921
Graff Yang28d7a6a2009-08-18 14:11:17 -0700922 /* The file shall have been opened with read permission. */
923 if (!(file->f_mode & FMODE_READ))
924 return -EACCES;
925
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 if (flags & MAP_SHARED) {
927 /* do checks for writing, appending and locking */
928 if ((prot & PROT_WRITE) &&
929 !(file->f_mode & FMODE_WRITE))
930 return -EACCES;
931
Josef Sipeke9536ae2006-12-08 02:37:21 -0800932 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 (file->f_mode & FMODE_WRITE))
934 return -EACCES;
935
Josef Sipeke9536ae2006-12-08 02:37:21 -0800936 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 return -EAGAIN;
938
939 if (!(capabilities & BDI_CAP_MAP_DIRECT))
940 return -ENODEV;
941
942 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
943 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
944 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
945 ) {
946 printk("MAP_SHARED not completely supported on !MMU\n");
947 return -EINVAL;
948 }
949
950 /* we mustn't privatise shared mappings */
951 capabilities &= ~BDI_CAP_MAP_COPY;
952 }
953 else {
954 /* we're going to read the file into private memory we
955 * allocate */
956 if (!(capabilities & BDI_CAP_MAP_COPY))
957 return -ENODEV;
958
959 /* we don't permit a private writable mapping to be
960 * shared with the backing device */
961 if (prot & PROT_WRITE)
962 capabilities &= ~BDI_CAP_MAP_DIRECT;
963 }
964
965 /* handle executable mappings and implied executable
966 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800967 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968 if (prot & PROT_EXEC)
969 return -EPERM;
970 }
971 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
972 /* handle implication of PROT_EXEC by PROT_READ */
973 if (current->personality & READ_IMPLIES_EXEC) {
974 if (capabilities & BDI_CAP_EXEC_MAP)
975 prot |= PROT_EXEC;
976 }
977 }
978 else if ((prot & PROT_READ) &&
979 (prot & PROT_EXEC) &&
980 !(capabilities & BDI_CAP_EXEC_MAP)
981 ) {
982 /* backing file is not executable, try to copy */
983 capabilities &= ~BDI_CAP_MAP_DIRECT;
984 }
985 }
986 else {
987 /* anonymous mappings are always memory backed and can be
988 * privately mapped
989 */
990 capabilities = BDI_CAP_MAP_COPY;
991
992 /* handle PROT_EXEC implication by PROT_READ */
993 if ((prot & PROT_READ) &&
994 (current->personality & READ_IMPLIES_EXEC))
995 prot |= PROT_EXEC;
996 }
997
998 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400999 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 if (ret < 0)
1001 return ret;
1002
1003 /* looks okay */
1004 *_capabilities = capabilities;
1005 return 0;
1006}
1007
1008/*
1009 * we've determined that we can make the mapping, now translate what we
1010 * now know into VMA flags
1011 */
1012static unsigned long determine_vm_flags(struct file *file,
1013 unsigned long prot,
1014 unsigned long flags,
1015 unsigned long capabilities)
1016{
1017 unsigned long vm_flags;
1018
1019 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
1020 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1021 /* vm_flags |= mm->def_flags; */
1022
1023 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1024 /* attempt to share read-only copies of mapped file chunks */
1025 if (file && !(prot & PROT_WRITE))
1026 vm_flags |= VM_MAYSHARE;
1027 }
1028 else {
1029 /* overlay a shareable mapping on the backing device or inode
1030 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1031 * romfs/cramfs */
1032 if (flags & MAP_SHARED)
1033 vm_flags |= VM_MAYSHARE | VM_SHARED;
1034 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1035 vm_flags |= VM_MAYSHARE;
1036 }
1037
1038 /* refuse to let anyone share private mappings with this process if
1039 * it's being traced - otherwise breakpoints set in it may interfere
1040 * with another untraced process
1041 */
Roland McGrathfa8e26c2008-07-25 19:45:50 -07001042 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 vm_flags &= ~VM_MAYSHARE;
1044
1045 return vm_flags;
1046}
1047
1048/*
David Howells8feae132009-01-08 12:04:47 +00001049 * set up a shared mapping on a file (the driver or filesystem provides and
1050 * pins the storage)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051 */
David Howells8feae132009-01-08 12:04:47 +00001052static int do_mmap_shared_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053{
1054 int ret;
1055
1056 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001057 if (ret == 0) {
1058 vma->vm_region->vm_top = vma->vm_region->vm_end;
1059 return ret;
1060 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061 if (ret != -ENOSYS)
1062 return ret;
1063
1064 /* getting an ENOSYS error indicates that direct mmap isn't
1065 * possible (as opposed to tried but failed) so we'll fall
1066 * through to making a private copy of the data and mapping
1067 * that if we can */
1068 return -ENODEV;
1069}
1070
1071/*
1072 * set up a private mapping or an anonymous shared mapping
1073 */
David Howells8feae132009-01-08 12:04:47 +00001074static int do_mmap_private(struct vm_area_struct *vma,
1075 struct vm_region *region,
1076 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077{
David Howells8feae132009-01-08 12:04:47 +00001078 struct page *pages;
1079 unsigned long total, point, n, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 void *base;
David Howells8feae132009-01-08 12:04:47 +00001081 int ret, order;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082
1083 /* invoke the file's mapping function so that it can keep track of
1084 * shared mappings on devices or memory
1085 * - VM_MAYSHARE will be set if it may attempt to share
1086 */
1087 if (vma->vm_file) {
1088 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001089 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 /* shouldn't return success if we're not sharing */
Paul Mundtdd8632a2009-01-08 12:04:47 +00001091 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1092 vma->vm_region->vm_top = vma->vm_region->vm_end;
1093 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 }
Paul Mundtdd8632a2009-01-08 12:04:47 +00001095 if (ret != -ENOSYS)
1096 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097
1098 /* getting an ENOSYS error indicates that direct mmap isn't
1099 * possible (as opposed to tried but failed) so we'll try to
1100 * make a private copy of the data and map that instead */
1101 }
1102
David Howells8feae132009-01-08 12:04:47 +00001103 rlen = PAGE_ALIGN(len);
1104
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 /* allocate some memory to hold the mapping
1106 * - note that this may not return a page-aligned address if the object
1107 * we're allocating is smaller than a page
1108 */
David Howells8feae132009-01-08 12:04:47 +00001109 order = get_order(rlen);
1110 kdebug("alloc order %d for %lx", order, len);
1111
1112 pages = alloc_pages(GFP_KERNEL, order);
1113 if (!pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001114 goto enomem;
1115
David Howells8feae132009-01-08 12:04:47 +00001116 total = 1 << order;
David Howells33e5d7692009-04-02 16:56:32 -07001117 atomic_long_add(total, &mmap_pages_allocated);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118
David Howells8feae132009-01-08 12:04:47 +00001119 point = rlen >> PAGE_SHIFT;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001120
1121 /* we allocated a power-of-2 sized page set, so we may want to trim off
1122 * the excess */
1123 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1124 while (total > point) {
1125 order = ilog2(total - point);
1126 n = 1 << order;
1127 kdebug("shave %lu/%lu @%lu", n, total - point, total);
David Howells33e5d7692009-04-02 16:56:32 -07001128 atomic_long_sub(n, &mmap_pages_allocated);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001129 total -= n;
1130 set_page_refcounted(pages + total);
1131 __free_pages(pages + total, order);
1132 }
David Howells8feae132009-01-08 12:04:47 +00001133 }
1134
David Howells8feae132009-01-08 12:04:47 +00001135 for (point = 1; point < total; point++)
1136 set_page_refcounted(&pages[point]);
1137
1138 base = page_address(pages);
1139 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1140 region->vm_start = (unsigned long) base;
1141 region->vm_end = region->vm_start + rlen;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001142 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
David Howells8feae132009-01-08 12:04:47 +00001143
1144 vma->vm_start = region->vm_start;
1145 vma->vm_end = region->vm_start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001146
1147 if (vma->vm_file) {
1148 /* read the contents of a file into the copy */
1149 mm_segment_t old_fs;
1150 loff_t fpos;
1151
1152 fpos = vma->vm_pgoff;
1153 fpos <<= PAGE_SHIFT;
1154
1155 old_fs = get_fs();
1156 set_fs(KERNEL_DS);
David Howells8feae132009-01-08 12:04:47 +00001157 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001158 set_fs(old_fs);
1159
1160 if (ret < 0)
1161 goto error_free;
1162
1163 /* clear the last little bit */
David Howells8feae132009-01-08 12:04:47 +00001164 if (ret < rlen)
1165 memset(base + ret, 0, rlen - ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166
1167 } else {
1168 /* if it's an anonymous mapping, then just clear it */
David Howells8feae132009-01-08 12:04:47 +00001169 memset(base, 0, rlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 }
1171
1172 return 0;
1173
1174error_free:
David Howells8feae132009-01-08 12:04:47 +00001175 free_page_series(region->vm_start, region->vm_end);
1176 region->vm_start = vma->vm_start = 0;
1177 region->vm_end = vma->vm_end = 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001178 region->vm_top = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 return ret;
1180
1181enomem:
Greg Ungerer05ae6fa2009-01-13 17:30:22 +10001182 printk("Allocation of length %lu from process %d (%s) failed\n",
1183 len, current->pid, current->comm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 show_free_areas();
1185 return -ENOMEM;
1186}
1187
1188/*
1189 * handle mapping creation for uClinux
1190 */
1191unsigned long do_mmap_pgoff(struct file *file,
1192 unsigned long addr,
1193 unsigned long len,
1194 unsigned long prot,
1195 unsigned long flags,
1196 unsigned long pgoff)
1197{
David Howells8feae132009-01-08 12:04:47 +00001198 struct vm_area_struct *vma;
1199 struct vm_region *region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 struct rb_node *rb;
David Howells8feae132009-01-08 12:04:47 +00001201 unsigned long capabilities, vm_flags, result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001202 int ret;
1203
David Howells8feae132009-01-08 12:04:47 +00001204 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1205
Eric Paris7cd94142007-11-26 18:47:40 -05001206 if (!(flags & MAP_FIXED))
1207 addr = round_hint_to_min(addr);
1208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 /* decide whether we should attempt the mapping, and if so what sort of
1210 * mapping */
1211 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1212 &capabilities);
David Howells8feae132009-01-08 12:04:47 +00001213 if (ret < 0) {
1214 kleave(" = %d [val]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001215 return ret;
David Howells8feae132009-01-08 12:04:47 +00001216 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217
1218 /* we've determined that we can make the mapping, now translate what we
1219 * now know into VMA flags */
1220 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1221
David Howells8feae132009-01-08 12:04:47 +00001222 /* we're going to need to record the mapping */
1223 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1224 if (!region)
1225 goto error_getting_region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226
David Howells8feae132009-01-08 12:04:47 +00001227 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1228 if (!vma)
1229 goto error_getting_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230
David Howells8feae132009-01-08 12:04:47 +00001231 atomic_set(&region->vm_usage, 1);
1232 region->vm_flags = vm_flags;
1233 region->vm_pgoff = pgoff;
1234
1235 INIT_LIST_HEAD(&vma->anon_vma_node);
1236 vma->vm_flags = vm_flags;
1237 vma->vm_pgoff = pgoff;
1238
1239 if (file) {
1240 region->vm_file = file;
1241 get_file(file);
1242 vma->vm_file = file;
1243 get_file(file);
1244 if (vm_flags & VM_EXECUTABLE) {
1245 added_exe_file_vma(current->mm);
1246 vma->vm_mm = current->mm;
1247 }
1248 }
1249
1250 down_write(&nommu_region_sem);
1251
1252 /* if we want to share, we need to check for regions created by other
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253 * mmap() calls that overlap with our proposed mapping
David Howells8feae132009-01-08 12:04:47 +00001254 * - we can only share with a superset match on most regular files
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255 * - shared mappings on character devices and memory backed files are
1256 * permitted to overlap inexactly as far as we are concerned for in
1257 * these cases, sharing is handled in the driver or filesystem rather
1258 * than here
1259 */
1260 if (vm_flags & VM_MAYSHARE) {
David Howells8feae132009-01-08 12:04:47 +00001261 struct vm_region *pregion;
1262 unsigned long pglen, rpglen, pgend, rpgend, start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001263
David Howells8feae132009-01-08 12:04:47 +00001264 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1265 pgend = pgoff + pglen;
David Howells165b2392007-03-22 00:11:24 -08001266
David Howells8feae132009-01-08 12:04:47 +00001267 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1268 pregion = rb_entry(rb, struct vm_region, vm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269
David Howells8feae132009-01-08 12:04:47 +00001270 if (!(pregion->vm_flags & VM_MAYSHARE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271 continue;
1272
1273 /* search for overlapping mappings on the same file */
David Howells8feae132009-01-08 12:04:47 +00001274 if (pregion->vm_file->f_path.dentry->d_inode !=
1275 file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001276 continue;
1277
David Howells8feae132009-01-08 12:04:47 +00001278 if (pregion->vm_pgoff >= pgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 continue;
1280
David Howells8feae132009-01-08 12:04:47 +00001281 rpglen = pregion->vm_end - pregion->vm_start;
1282 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1283 rpgend = pregion->vm_pgoff + rpglen;
1284 if (pgoff >= rpgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001285 continue;
1286
David Howells8feae132009-01-08 12:04:47 +00001287 /* handle inexactly overlapping matches between
1288 * mappings */
1289 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1290 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1291 /* new mapping is not a subset of the region */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1293 goto sharing_violation;
1294 continue;
1295 }
1296
David Howells8feae132009-01-08 12:04:47 +00001297 /* we've found a region we can share */
1298 atomic_inc(&pregion->vm_usage);
1299 vma->vm_region = pregion;
1300 start = pregion->vm_start;
1301 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1302 vma->vm_start = start;
1303 vma->vm_end = start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304
David Howells8feae132009-01-08 12:04:47 +00001305 if (pregion->vm_flags & VM_MAPPED_COPY) {
1306 kdebug("share copy");
1307 vma->vm_flags |= VM_MAPPED_COPY;
1308 } else {
1309 kdebug("share mmap");
1310 ret = do_mmap_shared_file(vma);
1311 if (ret < 0) {
1312 vma->vm_region = NULL;
1313 vma->vm_start = 0;
1314 vma->vm_end = 0;
1315 atomic_dec(&pregion->vm_usage);
1316 pregion = NULL;
1317 goto error_just_free;
1318 }
1319 }
1320 fput(region->vm_file);
1321 kmem_cache_free(vm_region_jar, region);
1322 region = pregion;
1323 result = start;
1324 goto share;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 }
1326
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 /* obtain the address at which to make a shared mapping
1328 * - this is the hook for quasi-memory character devices to
1329 * tell us the location of a shared mapping
1330 */
1331 if (file && file->f_op->get_unmapped_area) {
1332 addr = file->f_op->get_unmapped_area(file, addr, len,
1333 pgoff, flags);
1334 if (IS_ERR((void *) addr)) {
1335 ret = addr;
1336 if (ret != (unsigned long) -ENOSYS)
David Howells8feae132009-01-08 12:04:47 +00001337 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001338
1339 /* the driver refused to tell us where to site
1340 * the mapping so we'll have to attempt to copy
1341 * it */
1342 ret = (unsigned long) -ENODEV;
1343 if (!(capabilities & BDI_CAP_MAP_COPY))
David Howells8feae132009-01-08 12:04:47 +00001344 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
1346 capabilities &= ~BDI_CAP_MAP_DIRECT;
David Howells8feae132009-01-08 12:04:47 +00001347 } else {
1348 vma->vm_start = region->vm_start = addr;
1349 vma->vm_end = region->vm_end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 }
1351 }
1352 }
1353
David Howells8feae132009-01-08 12:04:47 +00001354 vma->vm_region = region;
David Howellsa1908872009-09-05 11:17:07 -07001355 add_nommu_region(region);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356
1357 /* set up the mapping */
1358 if (file && vma->vm_flags & VM_SHARED)
David Howells8feae132009-01-08 12:04:47 +00001359 ret = do_mmap_shared_file(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 else
David Howells8feae132009-01-08 12:04:47 +00001361 ret = do_mmap_private(vma, region, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001362 if (ret < 0)
David Howells8feae132009-01-08 12:04:47 +00001363 goto error_put_region;
1364
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365 /* okay... we have a mapping; now we have to register it */
David Howells8feae132009-01-08 12:04:47 +00001366 result = vma->vm_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 current->mm->total_vm += len >> PAGE_SHIFT;
1369
David Howells8feae132009-01-08 12:04:47 +00001370share:
1371 add_vma_to_mm(current->mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001372
David Howells8feae132009-01-08 12:04:47 +00001373 up_write(&nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374
1375 if (prot & PROT_EXEC)
David Howells8feae132009-01-08 12:04:47 +00001376 flush_icache_range(result, result + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377
David Howells8feae132009-01-08 12:04:47 +00001378 kleave(" = %lx", result);
1379 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001380
David Howells8feae132009-01-08 12:04:47 +00001381error_put_region:
1382 __put_nommu_region(region);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001383 if (vma) {
Matt Helsley925d1c42008-04-29 01:01:36 -07001384 if (vma->vm_file) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -07001385 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001386 if (vma->vm_flags & VM_EXECUTABLE)
1387 removed_exe_file_vma(vma->vm_mm);
1388 }
David Howells8feae132009-01-08 12:04:47 +00001389 kmem_cache_free(vm_area_cachep, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390 }
David Howells8feae132009-01-08 12:04:47 +00001391 kleave(" = %d [pr]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 return ret;
1393
David Howells8feae132009-01-08 12:04:47 +00001394error_just_free:
1395 up_write(&nommu_region_sem);
1396error:
1397 fput(region->vm_file);
1398 kmem_cache_free(vm_region_jar, region);
1399 fput(vma->vm_file);
1400 if (vma->vm_flags & VM_EXECUTABLE)
1401 removed_exe_file_vma(vma->vm_mm);
1402 kmem_cache_free(vm_area_cachep, vma);
1403 kleave(" = %d", ret);
1404 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405
David Howells8feae132009-01-08 12:04:47 +00001406sharing_violation:
1407 up_write(&nommu_region_sem);
1408 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1409 ret = -EINVAL;
1410 goto error;
1411
1412error_getting_vma:
1413 kmem_cache_free(vm_region_jar, region);
1414 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1415 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416 len, current->pid);
1417 show_free_areas();
1418 return -ENOMEM;
1419
David Howells8feae132009-01-08 12:04:47 +00001420error_getting_region:
1421 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1422 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423 len, current->pid);
1424 show_free_areas();
1425 return -ENOMEM;
1426}
Paul Mundtb5073172007-07-21 04:37:25 -07001427EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001428
1429/*
David Howells8feae132009-01-08 12:04:47 +00001430 * split a vma into two pieces at address 'addr', a new vma is allocated either
1431 * for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432 */
David Howells8feae132009-01-08 12:04:47 +00001433int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1434 unsigned long addr, int new_below)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435{
David Howells8feae132009-01-08 12:04:47 +00001436 struct vm_area_struct *new;
1437 struct vm_region *region;
1438 unsigned long npages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439
David Howells8feae132009-01-08 12:04:47 +00001440 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441
David Howells8feae132009-01-08 12:04:47 +00001442 /* we're only permitted to split anonymous regions that have a single
1443 * owner */
1444 if (vma->vm_file ||
1445 atomic_read(&vma->vm_region->vm_usage) != 1)
1446 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447
David Howells8feae132009-01-08 12:04:47 +00001448 if (mm->map_count >= sysctl_max_map_count)
1449 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001450
David Howells8feae132009-01-08 12:04:47 +00001451 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1452 if (!region)
1453 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454
David Howells8feae132009-01-08 12:04:47 +00001455 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1456 if (!new) {
1457 kmem_cache_free(vm_region_jar, region);
1458 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 }
David Howells8feae132009-01-08 12:04:47 +00001460
1461 /* most fields are the same, copy all, and then fixup */
1462 *new = *vma;
1463 *region = *vma->vm_region;
1464 new->vm_region = region;
1465
1466 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1467
1468 if (new_below) {
Paul Mundtdd8632a2009-01-08 12:04:47 +00001469 region->vm_top = region->vm_end = new->vm_end = addr;
David Howells8feae132009-01-08 12:04:47 +00001470 } else {
1471 region->vm_start = new->vm_start = addr;
1472 region->vm_pgoff = new->vm_pgoff += npages;
1473 }
1474
1475 if (new->vm_ops && new->vm_ops->open)
1476 new->vm_ops->open(new);
1477
1478 delete_vma_from_mm(vma);
1479 down_write(&nommu_region_sem);
1480 delete_nommu_region(vma->vm_region);
1481 if (new_below) {
1482 vma->vm_region->vm_start = vma->vm_start = addr;
1483 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1484 } else {
1485 vma->vm_region->vm_end = vma->vm_end = addr;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001486 vma->vm_region->vm_top = addr;
David Howells8feae132009-01-08 12:04:47 +00001487 }
1488 add_nommu_region(vma->vm_region);
1489 add_nommu_region(new->vm_region);
1490 up_write(&nommu_region_sem);
1491 add_vma_to_mm(mm, vma);
1492 add_vma_to_mm(mm, new);
1493 return 0;
1494}
1495
1496/*
1497 * shrink a VMA by removing the specified chunk from either the beginning or
1498 * the end
1499 */
1500static int shrink_vma(struct mm_struct *mm,
1501 struct vm_area_struct *vma,
1502 unsigned long from, unsigned long to)
1503{
1504 struct vm_region *region;
1505
1506 kenter("");
1507
1508 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1509 * and list */
1510 delete_vma_from_mm(vma);
1511 if (from > vma->vm_start)
1512 vma->vm_end = from;
1513 else
1514 vma->vm_start = to;
1515 add_vma_to_mm(mm, vma);
1516
1517 /* cut the backing region down to size */
1518 region = vma->vm_region;
1519 BUG_ON(atomic_read(&region->vm_usage) != 1);
1520
1521 down_write(&nommu_region_sem);
1522 delete_nommu_region(region);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001523 if (from > region->vm_start) {
1524 to = region->vm_top;
1525 region->vm_top = region->vm_end = from;
1526 } else {
David Howells8feae132009-01-08 12:04:47 +00001527 region->vm_start = to;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001528 }
David Howells8feae132009-01-08 12:04:47 +00001529 add_nommu_region(region);
1530 up_write(&nommu_region_sem);
1531
1532 free_page_series(from, to);
1533 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534}
1535
David Howells30340972006-09-27 01:50:20 -07001536/*
1537 * release a mapping
David Howells8feae132009-01-08 12:04:47 +00001538 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1539 * VMA, though it need not cover the whole VMA
David Howells30340972006-09-27 01:50:20 -07001540 */
David Howells8feae132009-01-08 12:04:47 +00001541int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001542{
David Howells8feae132009-01-08 12:04:47 +00001543 struct vm_area_struct *vma;
1544 struct rb_node *rb;
1545 unsigned long end = start + len;
1546 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001547
David Howells8feae132009-01-08 12:04:47 +00001548 kenter(",%lx,%zx", start, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001549
David Howells8feae132009-01-08 12:04:47 +00001550 if (len == 0)
1551 return -EINVAL;
1552
1553 /* find the first potentially overlapping VMA */
1554 vma = find_vma(mm, start);
1555 if (!vma) {
David Howells33e5d7692009-04-02 16:56:32 -07001556 static int limit = 0;
1557 if (limit < 5) {
1558 printk(KERN_WARNING
1559 "munmap of memory not mmapped by process %d"
1560 " (%s): 0x%lx-0x%lx\n",
1561 current->pid, current->comm,
1562 start, start + len - 1);
1563 limit++;
1564 }
David Howells8feae132009-01-08 12:04:47 +00001565 return -EINVAL;
David Howells30340972006-09-27 01:50:20 -07001566 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567
David Howells8feae132009-01-08 12:04:47 +00001568 /* we're allowed to split an anonymous VMA but not a file-backed one */
1569 if (vma->vm_file) {
1570 do {
1571 if (start > vma->vm_start) {
1572 kleave(" = -EINVAL [miss]");
1573 return -EINVAL;
1574 }
1575 if (end == vma->vm_end)
1576 goto erase_whole_vma;
1577 rb = rb_next(&vma->vm_rb);
1578 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1579 } while (rb);
1580 kleave(" = -EINVAL [split file]");
1581 return -EINVAL;
1582 } else {
1583 /* the chunk must be a subset of the VMA found */
1584 if (start == vma->vm_start && end == vma->vm_end)
1585 goto erase_whole_vma;
1586 if (start < vma->vm_start || end > vma->vm_end) {
1587 kleave(" = -EINVAL [superset]");
1588 return -EINVAL;
1589 }
1590 if (start & ~PAGE_MASK) {
1591 kleave(" = -EINVAL [unaligned start]");
1592 return -EINVAL;
1593 }
1594 if (end != vma->vm_end && end & ~PAGE_MASK) {
1595 kleave(" = -EINVAL [unaligned split]");
1596 return -EINVAL;
1597 }
1598 if (start != vma->vm_start && end != vma->vm_end) {
1599 ret = split_vma(mm, vma, start, 1);
1600 if (ret < 0) {
1601 kleave(" = %d [split]", ret);
1602 return ret;
1603 }
1604 }
1605 return shrink_vma(mm, vma, start, end);
1606 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607
David Howells8feae132009-01-08 12:04:47 +00001608erase_whole_vma:
1609 delete_vma_from_mm(vma);
1610 delete_vma(mm, vma);
1611 kleave(" = 0");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612 return 0;
1613}
Paul Mundtb5073172007-07-21 04:37:25 -07001614EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001616SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
David Howells30340972006-09-27 01:50:20 -07001617{
1618 int ret;
1619 struct mm_struct *mm = current->mm;
1620
1621 down_write(&mm->mmap_sem);
1622 ret = do_munmap(mm, addr, len);
1623 up_write(&mm->mmap_sem);
1624 return ret;
1625}
1626
1627/*
David Howells8feae132009-01-08 12:04:47 +00001628 * release all the mappings made in a process's VM space
David Howells30340972006-09-27 01:50:20 -07001629 */
David Howells8feae132009-01-08 12:04:47 +00001630void exit_mmap(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631{
David Howells8feae132009-01-08 12:04:47 +00001632 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633
David Howells8feae132009-01-08 12:04:47 +00001634 if (!mm)
1635 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001636
David Howells8feae132009-01-08 12:04:47 +00001637 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638
David Howells8feae132009-01-08 12:04:47 +00001639 mm->total_vm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640
David Howells8feae132009-01-08 12:04:47 +00001641 while ((vma = mm->mmap)) {
1642 mm->mmap = vma->vm_next;
1643 delete_vma_from_mm(vma);
1644 delete_vma(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645 }
David Howells8feae132009-01-08 12:04:47 +00001646
1647 kleave("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648}
1649
Linus Torvalds1da177e2005-04-16 15:20:36 -07001650unsigned long do_brk(unsigned long addr, unsigned long len)
1651{
1652 return -ENOMEM;
1653}
1654
1655/*
David Howells6fa5f802006-09-27 01:50:21 -07001656 * expand (or shrink) an existing mapping, potentially moving it at the same
1657 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001658 *
David Howells6fa5f802006-09-27 01:50:21 -07001659 * under NOMMU conditions, we only permit changing a mapping's size, and only
David Howells8feae132009-01-08 12:04:47 +00001660 * as long as it stays within the region allocated by do_mmap_private() and the
1661 * block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 *
David Howells6fa5f802006-09-27 01:50:21 -07001663 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001664 */
1665unsigned long do_mremap(unsigned long addr,
1666 unsigned long old_len, unsigned long new_len,
1667 unsigned long flags, unsigned long new_addr)
1668{
David Howells6fa5f802006-09-27 01:50:21 -07001669 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001670
1671 /* insanity checks first */
David Howells8feae132009-01-08 12:04:47 +00001672 if (old_len == 0 || new_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001673 return (unsigned long) -EINVAL;
1674
David Howells8feae132009-01-08 12:04:47 +00001675 if (addr & ~PAGE_MASK)
1676 return -EINVAL;
1677
Linus Torvalds1da177e2005-04-16 15:20:36 -07001678 if (flags & MREMAP_FIXED && new_addr != addr)
1679 return (unsigned long) -EINVAL;
1680
David Howells8feae132009-01-08 12:04:47 +00001681 vma = find_vma_exact(current->mm, addr, old_len);
David Howells6fa5f802006-09-27 01:50:21 -07001682 if (!vma)
1683 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684
David Howells6fa5f802006-09-27 01:50:21 -07001685 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001686 return (unsigned long) -EFAULT;
1687
David Howells6fa5f802006-09-27 01:50:21 -07001688 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689 return (unsigned long) -EPERM;
1690
David Howells8feae132009-01-08 12:04:47 +00001691 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001692 return (unsigned long) -ENOMEM;
1693
1694 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001695 vma->vm_end = vma->vm_start + new_len;
David Howells6fa5f802006-09-27 01:50:21 -07001696 return vma->vm_start;
1697}
Paul Mundtb5073172007-07-21 04:37:25 -07001698EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001699
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001700SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1701 unsigned long, new_len, unsigned long, flags,
1702 unsigned long, new_addr)
David Howells6fa5f802006-09-27 01:50:21 -07001703{
1704 unsigned long ret;
1705
1706 down_write(&current->mm->mmap_sem);
1707 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1708 up_write(&current->mm->mmap_sem);
1709 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001710}
1711
Linus Torvalds6aab3412005-11-28 14:34:23 -08001712struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001713 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714{
1715 return NULL;
1716}
1717
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1719 unsigned long to, unsigned long size, pgprot_t prot)
1720{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001721 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1722 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001723}
Luke Yang22c4af42006-07-14 00:24:09 -07001724EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725
Paul Mundtf905bc42008-02-04 22:29:59 -08001726int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1727 unsigned long pgoff)
1728{
1729 unsigned int size = vma->vm_end - vma->vm_start;
1730
1731 if (!(vma->vm_flags & VM_USERMAP))
1732 return -EINVAL;
1733
1734 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1735 vma->vm_end = vma->vm_start + size;
1736
1737 return 0;
1738}
1739EXPORT_SYMBOL(remap_vmalloc_range);
1740
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1742{
1743}
1744
1745unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1746 unsigned long len, unsigned long pgoff, unsigned long flags)
1747{
1748 return -ENOMEM;
1749}
1750
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001751void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001752{
1753}
1754
Linus Torvalds1da177e2005-04-16 15:20:36 -07001755void unmap_mapping_range(struct address_space *mapping,
1756 loff_t const holebegin, loff_t const holelen,
1757 int even_cows)
1758{
1759}
Luke Yang22c4af42006-07-14 00:24:09 -07001760EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761
1762/*
David Howellsd56e03c2007-03-22 00:11:23 -08001763 * ask for an unmapped area at which to create a mapping on a file
1764 */
1765unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1766 unsigned long len, unsigned long pgoff,
1767 unsigned long flags)
1768{
1769 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1770 unsigned long, unsigned long);
1771
1772 get_area = current->mm->get_unmapped_area;
1773 if (file && file->f_op && file->f_op->get_unmapped_area)
1774 get_area = file->f_op->get_unmapped_area;
1775
1776 if (!get_area)
1777 return -ENOSYS;
1778
1779 return get_area(file, addr, len, pgoff, flags);
1780}
David Howellsd56e03c2007-03-22 00:11:23 -08001781EXPORT_SYMBOL(get_unmapped_area);
1782
1783/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 * Check that a process has enough memory to allocate a new virtual
1785 * mapping. 0 means there is enough memory for the allocation to
1786 * succeed and -ENOMEM implies there is not.
1787 *
1788 * We currently support three overcommit policies, which are set via the
1789 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1790 *
1791 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1792 * Additional code 2002 Jul 20 by Robert Love.
1793 *
1794 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1795 *
1796 * Note this is a helper function intended to be used by LSMs which
1797 * wish to use this logic.
1798 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001799int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800{
1801 unsigned long free, allowed;
1802
1803 vm_acct_memory(pages);
1804
1805 /*
1806 * Sometimes we want to use more memory than we have
1807 */
1808 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1809 return 0;
1810
1811 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1812 unsigned long n;
1813
Christoph Lameter347ce432006-06-30 01:55:35 -07001814 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 free += nr_swap_pages;
1816
1817 /*
1818 * Any slabs which are created with the
1819 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1820 * which are reclaimable, under pressure. The dentry
1821 * cache and most inode caches should fall into this
1822 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001823 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001824
1825 /*
1826 * Leave the last 3% for root
1827 */
1828 if (!cap_sys_admin)
1829 free -= free / 32;
1830
1831 if (free > pages)
1832 return 0;
1833
1834 /*
1835 * nr_free_pages() is very expensive on large systems,
1836 * only call if we're about to fail.
1837 */
1838 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001839
1840 /*
1841 * Leave reserved pages. The pages are not for anonymous pages.
1842 */
1843 if (n <= totalreserve_pages)
1844 goto error;
1845 else
1846 n -= totalreserve_pages;
1847
1848 /*
1849 * Leave the last 3% for root
1850 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851 if (!cap_sys_admin)
1852 n -= n / 32;
1853 free += n;
1854
1855 if (free > pages)
1856 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001857
1858 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859 }
1860
1861 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1862 /*
1863 * Leave the last 3% for root
1864 */
1865 if (!cap_sys_admin)
1866 allowed -= allowed / 32;
1867 allowed += total_swap_pages;
1868
1869 /* Don't let a single process grow too big:
1870 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -07001871 if (mm)
1872 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001874 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 return 0;
KOSAKI Motohiro00a62ce2009-04-30 15:08:51 -07001876
Hideo AOKId5ddc792006-04-10 22:53:01 -07001877error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001878 vm_unacct_memory(pages);
1879
1880 return -ENOMEM;
1881}
1882
1883int in_gate_area_no_task(unsigned long addr)
1884{
1885 return 0;
1886}
David Howellsb0e15192006-01-06 00:11:42 -08001887
Nick Piggind0217ac2007-07-19 01:47:03 -07001888int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001889{
1890 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001891 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001892}
Paul Mundtb5073172007-07-21 04:37:25 -07001893EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001894
1895/*
1896 * Access another process' address space.
1897 * - source/target buffer must be kernel space
1898 */
1899int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1900{
David Howells0ec76a12006-09-27 01:50:15 -07001901 struct vm_area_struct *vma;
1902 struct mm_struct *mm;
1903
1904 if (addr + len < addr)
1905 return 0;
1906
1907 mm = get_task_mm(tsk);
1908 if (!mm)
1909 return 0;
1910
1911 down_read(&mm->mmap_sem);
1912
1913 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001914 vma = find_vma(mm, addr);
1915 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001916 /* don't overrun this mapping */
1917 if (addr + len >= vma->vm_end)
1918 len = vma->vm_end - addr;
1919
1920 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07001921 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001922 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07001923 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001924 len -= copy_from_user(buf, (void *) addr, len);
1925 else
1926 len = 0;
1927 } else {
1928 len = 0;
1929 }
1930
1931 up_read(&mm->mmap_sem);
1932 mmput(mm);
1933 return len;
1934}