blob: 72eda4aee2cb46d72e070271d82ae13daef78b36 [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;
Alan Cox80119ef2008-05-23 13:04:31 -070065atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
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;
Paul Mundtdd8632a2009-01-08 12:04:47 +000069int sysctl_nr_trim_pages = 1; /* page trimming behaviour */
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 Mundt6cfd53f2008-06-05 22:46:08 -0700140 return 0;
141
142 page = virt_to_head_page(objp);
Paul Mundt6cfd53f2008-06-05 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 Mundt6cfd53f2008-06-05 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 Mundt6cfd53f2008-06-05 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 Mundt6cfd53f2008-06-05 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,
173 unsigned long start, int len, 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
189 for (i = 0; i < len; 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,
224 unsigned long start, int len, int write, int force,
225 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
234 return __get_user_pages(tsk, mm,
235 start, len, flags,
236 pages, vmas);
237}
Greg Ungerer66aa2b42005-09-12 11:18:10 +1000238EXPORT_SYMBOL(get_user_pages);
239
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240DEFINE_RWLOCK(vmlist_lock);
241struct vm_struct *vmlist;
242
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800243void vfree(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244{
245 kfree(addr);
246}
Paul Mundtb5073172007-07-21 04:37:25 -0700247EXPORT_SYMBOL(vfree);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248
Al Virodd0fc662005-10-07 07:46:04 +0100249void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250{
251 /*
Robert P. J. Day85186092007-10-19 23:11:38 +0200252 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
253 * returns only a logical address.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 */
Nick Piggin84097512006-03-22 00:08:34 -0800255 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256}
Paul Mundtb5073172007-07-21 04:37:25 -0700257EXPORT_SYMBOL(__vmalloc);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700258
Paul Mundtf905bc42008-02-04 22:29:59 -0800259void *vmalloc_user(unsigned long size)
260{
261 void *ret;
262
263 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
264 PAGE_KERNEL);
265 if (ret) {
266 struct vm_area_struct *vma;
267
268 down_write(&current->mm->mmap_sem);
269 vma = find_vma(current->mm, (unsigned long)ret);
270 if (vma)
271 vma->vm_flags |= VM_USERMAP;
272 up_write(&current->mm->mmap_sem);
273 }
274
275 return ret;
276}
277EXPORT_SYMBOL(vmalloc_user);
278
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800279struct page *vmalloc_to_page(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
281 return virt_to_page(addr);
282}
Paul Mundtb5073172007-07-21 04:37:25 -0700283EXPORT_SYMBOL(vmalloc_to_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800285unsigned long vmalloc_to_pfn(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700286{
287 return page_to_pfn(virt_to_page(addr));
288}
Paul Mundtb5073172007-07-21 04:37:25 -0700289EXPORT_SYMBOL(vmalloc_to_pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290
291long vread(char *buf, char *addr, unsigned long count)
292{
293 memcpy(buf, addr, count);
294 return count;
295}
296
297long vwrite(char *buf, char *addr, unsigned long count)
298{
299 /* Don't allow overflow */
300 if ((unsigned long) addr + count < count)
301 count = -(unsigned long) addr;
302
303 memcpy(addr, buf, count);
304 return(count);
305}
306
307/*
308 * vmalloc - allocate virtually continguos memory
309 *
310 * @size: allocation size
311 *
312 * Allocate enough pages to cover @size from the page level
313 * allocator and map them into continguos kernel virtual space.
314 *
Michael Opdenackerc1c88972006-10-03 23:21:02 +0200315 * For tight control over page level allocator and protection flags
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 * use __vmalloc() instead.
317 */
318void *vmalloc(unsigned long size)
319{
320 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
321}
Andrew Mortonf6138882006-02-28 16:59:18 -0800322EXPORT_SYMBOL(vmalloc);
323
324void *vmalloc_node(unsigned long size, int node)
325{
326 return vmalloc(size);
327}
328EXPORT_SYMBOL(vmalloc_node);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700329
Paul Mundt1af446e2008-08-04 16:01:47 +0900330#ifndef PAGE_KERNEL_EXEC
331# define PAGE_KERNEL_EXEC PAGE_KERNEL
332#endif
333
334/**
335 * vmalloc_exec - allocate virtually contiguous, executable memory
336 * @size: allocation size
337 *
338 * Kernel-internal function to allocate enough pages to cover @size
339 * the page level allocator and map them into contiguous and
340 * executable kernel virtual space.
341 *
342 * For tight control over page level allocator and protection flags
343 * use __vmalloc() instead.
344 */
345
346void *vmalloc_exec(unsigned long size)
347{
348 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
349}
350
Paul Mundtb5073172007-07-21 04:37:25 -0700351/**
352 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 * @size: allocation size
354 *
355 * Allocate enough 32bit PA addressable pages to cover @size from the
356 * page level allocator and map them into continguos kernel virtual space.
357 */
358void *vmalloc_32(unsigned long size)
359{
360 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
361}
Paul Mundtb5073172007-07-21 04:37:25 -0700362EXPORT_SYMBOL(vmalloc_32);
363
364/**
365 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
366 * @size: allocation size
367 *
368 * The resulting memory area is 32bit addressable and zeroed so it can be
369 * mapped to userspace without leaking data.
Paul Mundtf905bc42008-02-04 22:29:59 -0800370 *
371 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
372 * remap_vmalloc_range() are permissible.
Paul Mundtb5073172007-07-21 04:37:25 -0700373 */
374void *vmalloc_32_user(unsigned long size)
375{
Paul Mundtf905bc42008-02-04 22:29:59 -0800376 /*
377 * We'll have to sort out the ZONE_DMA bits for 64-bit,
378 * but for now this can simply use vmalloc_user() directly.
379 */
380 return vmalloc_user(size);
Paul Mundtb5073172007-07-21 04:37:25 -0700381}
382EXPORT_SYMBOL(vmalloc_32_user);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383
384void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
385{
386 BUG();
387 return NULL;
388}
Paul Mundtb5073172007-07-21 04:37:25 -0700389EXPORT_SYMBOL(vmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700390
Christoph Lameterb3bdda02008-02-04 22:28:32 -0800391void vunmap(const void *addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392{
393 BUG();
394}
Paul Mundtb5073172007-07-21 04:37:25 -0700395EXPORT_SYMBOL(vunmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396
Paul Mundteb6434d2009-01-21 17:45:47 +0900397void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
398{
399 BUG();
400 return NULL;
401}
402EXPORT_SYMBOL(vm_map_ram);
403
404void vm_unmap_ram(const void *mem, unsigned int count)
405{
406 BUG();
407}
408EXPORT_SYMBOL(vm_unmap_ram);
409
410void vm_unmap_aliases(void)
411{
412}
413EXPORT_SYMBOL_GPL(vm_unmap_aliases);
414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700416 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
417 * have one.
418 */
419void __attribute__((weak)) vmalloc_sync_all(void)
420{
421}
422
Paul Mundtb5073172007-07-21 04:37:25 -0700423int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
424 struct page *page)
425{
426 return -EINVAL;
427}
428EXPORT_SYMBOL(vm_insert_page);
429
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700430/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 * sys_brk() for the most part doesn't need the global kernel
432 * lock, except when an application is doing something nasty
433 * like trying to un-brk an area that has already been mapped
434 * to a regular file. in this case, the unmapping will need
435 * to invoke file system routines that need the global lock.
436 */
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100437SYSCALL_DEFINE1(brk, unsigned long, brk)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438{
439 struct mm_struct *mm = current->mm;
440
441 if (brk < mm->start_brk || brk > mm->context.end_brk)
442 return mm->brk;
443
444 if (mm->brk == brk)
445 return mm->brk;
446
447 /*
448 * Always allow shrinking brk
449 */
450 if (brk <= mm->brk) {
451 mm->brk = brk;
452 return brk;
453 }
454
455 /*
456 * Ok, looks good - let it rip.
457 */
458 return mm->brk = brk;
459}
460
David Howells8feae132009-01-08 12:04:47 +0000461/*
462 * initialise the VMA and region record slabs
463 */
464void __init mmap_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465{
David Howells33e5d7692009-04-02 16:56:32 -0700466 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
David Howells8feae132009-01-08 12:04:47 +0000467}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
David Howells8feae132009-01-08 12:04:47 +0000469/*
470 * validate the region tree
471 * - the caller must hold the region lock
472 */
473#ifdef CONFIG_DEBUG_NOMMU_REGIONS
474static noinline void validate_nommu_regions(void)
475{
476 struct vm_region *region, *last;
477 struct rb_node *p, *lastp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478
David Howells8feae132009-01-08 12:04:47 +0000479 lastp = rb_first(&nommu_region_tree);
480 if (!lastp)
481 return;
482
483 last = rb_entry(lastp, struct vm_region, vm_rb);
David Howells33e5d7692009-04-02 16:56:32 -0700484 BUG_ON(unlikely(last->vm_end <= last->vm_start));
485 BUG_ON(unlikely(last->vm_top < last->vm_end));
David Howells8feae132009-01-08 12:04:47 +0000486
487 while ((p = rb_next(lastp))) {
488 region = rb_entry(p, struct vm_region, vm_rb);
489 last = rb_entry(lastp, struct vm_region, vm_rb);
490
David Howells33e5d7692009-04-02 16:56:32 -0700491 BUG_ON(unlikely(region->vm_end <= region->vm_start));
492 BUG_ON(unlikely(region->vm_top < region->vm_end));
493 BUG_ON(unlikely(region->vm_start < last->vm_top));
David Howells8feae132009-01-08 12:04:47 +0000494
495 lastp = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 }
497}
David Howells8feae132009-01-08 12:04:47 +0000498#else
David Howells33e5d7692009-04-02 16:56:32 -0700499static void validate_nommu_regions(void)
500{
501}
David Howells8feae132009-01-08 12:04:47 +0000502#endif
503
504/*
505 * add a region into the global tree
506 */
507static void add_nommu_region(struct vm_region *region)
508{
509 struct vm_region *pregion;
510 struct rb_node **p, *parent;
511
512 validate_nommu_regions();
513
514 BUG_ON(region->vm_start & ~PAGE_MASK);
515
516 parent = NULL;
517 p = &nommu_region_tree.rb_node;
518 while (*p) {
519 parent = *p;
520 pregion = rb_entry(parent, struct vm_region, vm_rb);
521 if (region->vm_start < pregion->vm_start)
522 p = &(*p)->rb_left;
523 else if (region->vm_start > pregion->vm_start)
524 p = &(*p)->rb_right;
525 else if (pregion == region)
526 return;
527 else
528 BUG();
529 }
530
531 rb_link_node(&region->vm_rb, parent, p);
532 rb_insert_color(&region->vm_rb, &nommu_region_tree);
533
534 validate_nommu_regions();
535}
536
537/*
538 * delete a region from the global tree
539 */
540static void delete_nommu_region(struct vm_region *region)
541{
542 BUG_ON(!nommu_region_tree.rb_node);
543
544 validate_nommu_regions();
545 rb_erase(&region->vm_rb, &nommu_region_tree);
546 validate_nommu_regions();
547}
548
549/*
550 * free a contiguous series of pages
551 */
552static void free_page_series(unsigned long from, unsigned long to)
553{
554 for (; from < to; from += PAGE_SIZE) {
555 struct page *page = virt_to_page(from);
556
557 kdebug("- free %lx", from);
David Howells33e5d7692009-04-02 16:56:32 -0700558 atomic_long_dec(&mmap_pages_allocated);
David Howells8feae132009-01-08 12:04:47 +0000559 if (page_count(page) != 1)
David Howells33e5d7692009-04-02 16:56:32 -0700560 kdebug("free page %p: refcount not one: %d",
561 page, page_count(page));
David Howells8feae132009-01-08 12:04:47 +0000562 put_page(page);
563 }
564}
565
566/*
567 * release a reference to a region
David Howells33e5d7692009-04-02 16:56:32 -0700568 * - the caller must hold the region semaphore for writing, which this releases
Paul Mundtdd8632a2009-01-08 12:04:47 +0000569 * - the region may not have been added to the tree yet, in which case vm_top
David Howells8feae132009-01-08 12:04:47 +0000570 * will equal vm_start
571 */
572static void __put_nommu_region(struct vm_region *region)
573 __releases(nommu_region_sem)
574{
575 kenter("%p{%d}", region, atomic_read(&region->vm_usage));
576
577 BUG_ON(!nommu_region_tree.rb_node);
578
579 if (atomic_dec_and_test(&region->vm_usage)) {
Paul Mundtdd8632a2009-01-08 12:04:47 +0000580 if (region->vm_top > region->vm_start)
David Howells8feae132009-01-08 12:04:47 +0000581 delete_nommu_region(region);
582 up_write(&nommu_region_sem);
583
584 if (region->vm_file)
585 fput(region->vm_file);
586
587 /* IO memory and memory shared directly out of the pagecache
588 * from ramfs/tmpfs mustn't be released here */
589 if (region->vm_flags & VM_MAPPED_COPY) {
590 kdebug("free series");
Paul Mundtdd8632a2009-01-08 12:04:47 +0000591 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +0000592 }
593 kmem_cache_free(vm_region_jar, region);
594 } else {
595 up_write(&nommu_region_sem);
596 }
597}
598
599/*
600 * release a reference to a region
601 */
602static void put_nommu_region(struct vm_region *region)
603{
604 down_write(&nommu_region_sem);
605 __put_nommu_region(region);
606}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607
David Howells30340972006-09-27 01:50:20 -0700608/*
609 * add a VMA into a process's mm_struct in the appropriate place in the list
David Howells8feae132009-01-08 12:04:47 +0000610 * and tree and add to the address space's page tree also if not an anonymous
611 * page
David Howells30340972006-09-27 01:50:20 -0700612 * - should be called with mm->mmap_sem held writelocked
613 */
David Howells8feae132009-01-08 12:04:47 +0000614static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
David Howells30340972006-09-27 01:50:20 -0700615{
David Howells8feae132009-01-08 12:04:47 +0000616 struct vm_area_struct *pvma, **pp;
617 struct address_space *mapping;
618 struct rb_node **p, *parent;
David Howells30340972006-09-27 01:50:20 -0700619
David Howells8feae132009-01-08 12:04:47 +0000620 kenter(",%p", vma);
621
622 BUG_ON(!vma->vm_region);
623
624 mm->map_count++;
625 vma->vm_mm = mm;
626
627 /* add the VMA to the mapping */
628 if (vma->vm_file) {
629 mapping = vma->vm_file->f_mapping;
630
631 flush_dcache_mmap_lock(mapping);
632 vma_prio_tree_insert(vma, &mapping->i_mmap);
633 flush_dcache_mmap_unlock(mapping);
634 }
635
636 /* add the VMA to the tree */
637 parent = NULL;
638 p = &mm->mm_rb.rb_node;
639 while (*p) {
640 parent = *p;
641 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
642
643 /* sort by: start addr, end addr, VMA struct addr in that order
644 * (the latter is necessary as we may get identical VMAs) */
645 if (vma->vm_start < pvma->vm_start)
646 p = &(*p)->rb_left;
647 else if (vma->vm_start > pvma->vm_start)
648 p = &(*p)->rb_right;
649 else if (vma->vm_end < pvma->vm_end)
650 p = &(*p)->rb_left;
651 else if (vma->vm_end > pvma->vm_end)
652 p = &(*p)->rb_right;
653 else if (vma < pvma)
654 p = &(*p)->rb_left;
655 else if (vma > pvma)
656 p = &(*p)->rb_right;
657 else
658 BUG();
659 }
660
661 rb_link_node(&vma->vm_rb, parent, p);
662 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
663
664 /* add VMA to the VMA list also */
665 for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
666 if (pvma->vm_start > vma->vm_start)
David Howells30340972006-09-27 01:50:20 -0700667 break;
David Howells8feae132009-01-08 12:04:47 +0000668 if (pvma->vm_start < vma->vm_start)
669 continue;
670 if (pvma->vm_end < vma->vm_end)
671 break;
672 }
David Howells30340972006-09-27 01:50:20 -0700673
David Howells8feae132009-01-08 12:04:47 +0000674 vma->vm_next = *pp;
675 *pp = vma;
676}
677
678/*
679 * delete a VMA from its owning mm_struct and address space
680 */
681static void delete_vma_from_mm(struct vm_area_struct *vma)
682{
683 struct vm_area_struct **pp;
684 struct address_space *mapping;
685 struct mm_struct *mm = vma->vm_mm;
686
687 kenter("%p", vma);
688
689 mm->map_count--;
690 if (mm->mmap_cache == vma)
691 mm->mmap_cache = NULL;
692
693 /* remove the VMA from the mapping */
694 if (vma->vm_file) {
695 mapping = vma->vm_file->f_mapping;
696
697 flush_dcache_mmap_lock(mapping);
698 vma_prio_tree_remove(vma, &mapping->i_mmap);
699 flush_dcache_mmap_unlock(mapping);
700 }
701
702 /* remove from the MM's tree and list */
703 rb_erase(&vma->vm_rb, &mm->mm_rb);
704 for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
705 if (*pp == vma) {
706 *pp = vma->vm_next;
707 break;
708 }
709 }
710
711 vma->vm_mm = NULL;
712}
713
714/*
715 * destroy a VMA record
716 */
717static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
718{
719 kenter("%p", vma);
720 if (vma->vm_ops && vma->vm_ops->close)
721 vma->vm_ops->close(vma);
722 if (vma->vm_file) {
723 fput(vma->vm_file);
724 if (vma->vm_flags & VM_EXECUTABLE)
725 removed_exe_file_vma(mm);
726 }
727 put_nommu_region(vma->vm_region);
728 kmem_cache_free(vm_area_cachep, vma);
David Howells30340972006-09-27 01:50:20 -0700729}
730
731/*
732 * look up the first VMA in which addr resides, NULL if none
733 * - should be called with mm->mmap_sem at least held readlocked
734 */
735struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
736{
David Howells8feae132009-01-08 12:04:47 +0000737 struct vm_area_struct *vma;
738 struct rb_node *n = mm->mm_rb.rb_node;
David Howells30340972006-09-27 01:50:20 -0700739
David Howells8feae132009-01-08 12:04:47 +0000740 /* check the cache first */
741 vma = mm->mmap_cache;
742 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
743 return vma;
744
745 /* trawl the tree (there may be multiple mappings in which addr
746 * resides) */
747 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
748 vma = rb_entry(n, struct vm_area_struct, vm_rb);
749 if (vma->vm_start > addr)
750 return NULL;
751 if (vma->vm_end > addr) {
752 mm->mmap_cache = vma;
753 return vma;
754 }
David Howells30340972006-09-27 01:50:20 -0700755 }
756
David Howells30340972006-09-27 01:50:20 -0700757 return NULL;
758}
759EXPORT_SYMBOL(find_vma);
760
761/*
David Howells930e6522006-09-27 01:50:22 -0700762 * find a VMA
763 * - we don't extend stack VMAs under NOMMU conditions
764 */
765struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
766{
767 return find_vma(mm, addr);
768}
769
David Howells8feae132009-01-08 12:04:47 +0000770/*
771 * expand a stack to a given address
772 * - not supported under NOMMU conditions
773 */
Greg Ungerer57c8f632007-07-15 23:38:28 -0700774int expand_stack(struct vm_area_struct *vma, unsigned long address)
775{
776 return -ENOMEM;
777}
778
David Howells930e6522006-09-27 01:50:22 -0700779/*
David Howells6fa5f802006-09-27 01:50:21 -0700780 * look up the first VMA exactly that exactly matches addr
781 * - should be called with mm->mmap_sem at least held readlocked
782 */
David Howells8feae132009-01-08 12:04:47 +0000783static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
784 unsigned long addr,
785 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786{
787 struct vm_area_struct *vma;
David Howells8feae132009-01-08 12:04:47 +0000788 struct rb_node *n = mm->mm_rb.rb_node;
789 unsigned long end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790
David Howells8feae132009-01-08 12:04:47 +0000791 /* check the cache first */
792 vma = mm->mmap_cache;
793 if (vma && vma->vm_start == addr && vma->vm_end == end)
794 return vma;
795
796 /* trawl the tree (there may be multiple mappings in which addr
797 * resides) */
798 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 vma = rb_entry(n, struct vm_area_struct, vm_rb);
David Howells8feae132009-01-08 12:04:47 +0000800 if (vma->vm_start < addr)
801 continue;
802 if (vma->vm_start > addr)
803 return NULL;
804 if (vma->vm_end == end) {
805 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 return vma;
David Howells8feae132009-01-08 12:04:47 +0000807 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 }
809
810 return NULL;
811}
812
David Howells30340972006-09-27 01:50:20 -0700813/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 * determine whether a mapping should be permitted and, if so, what sort of
815 * mapping we're capable of supporting
816 */
817static int validate_mmap_request(struct file *file,
818 unsigned long addr,
819 unsigned long len,
820 unsigned long prot,
821 unsigned long flags,
822 unsigned long pgoff,
823 unsigned long *_capabilities)
824{
David Howells8feae132009-01-08 12:04:47 +0000825 unsigned long capabilities, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 unsigned long reqprot = prot;
827 int ret;
828
829 /* do the simple checks first */
830 if (flags & MAP_FIXED || addr) {
831 printk(KERN_DEBUG
832 "%d: Can't do fixed-address/overlay mmap of RAM\n",
833 current->pid);
834 return -EINVAL;
835 }
836
837 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
838 (flags & MAP_TYPE) != MAP_SHARED)
839 return -EINVAL;
840
Mike Frysingerf81cff02006-12-06 12:02:59 +1000841 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 return -EINVAL;
843
Mike Frysingerf81cff02006-12-06 12:02:59 +1000844 /* Careful about overflows.. */
David Howells8feae132009-01-08 12:04:47 +0000845 rlen = PAGE_ALIGN(len);
846 if (!rlen || rlen > TASK_SIZE)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000847 return -ENOMEM;
848
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 /* offset overflow? */
David Howells8feae132009-01-08 12:04:47 +0000850 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff02006-12-06 12:02:59 +1000851 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852
853 if (file) {
854 /* validate file mapping requests */
855 struct address_space *mapping;
856
857 /* files must support mmap */
858 if (!file->f_op || !file->f_op->mmap)
859 return -ENODEV;
860
861 /* work out if what we've got could possibly be shared
862 * - we support chardevs that provide their own "memory"
863 * - we support files/blockdevs that are memory backed
864 */
865 mapping = file->f_mapping;
866 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800867 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868
869 capabilities = 0;
870 if (mapping && mapping->backing_dev_info)
871 capabilities = mapping->backing_dev_info->capabilities;
872
873 if (!capabilities) {
874 /* no explicit capabilities set, so assume some
875 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800876 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 case S_IFREG:
878 case S_IFBLK:
879 capabilities = BDI_CAP_MAP_COPY;
880 break;
881
882 case S_IFCHR:
883 capabilities =
884 BDI_CAP_MAP_DIRECT |
885 BDI_CAP_READ_MAP |
886 BDI_CAP_WRITE_MAP;
887 break;
888
889 default:
890 return -EINVAL;
891 }
892 }
893
894 /* eliminate any capabilities that we can't support on this
895 * device */
896 if (!file->f_op->get_unmapped_area)
897 capabilities &= ~BDI_CAP_MAP_DIRECT;
898 if (!file->f_op->read)
899 capabilities &= ~BDI_CAP_MAP_COPY;
900
901 if (flags & MAP_SHARED) {
902 /* do checks for writing, appending and locking */
903 if ((prot & PROT_WRITE) &&
904 !(file->f_mode & FMODE_WRITE))
905 return -EACCES;
906
Josef Sipeke9536ae2006-12-08 02:37:21 -0800907 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908 (file->f_mode & FMODE_WRITE))
909 return -EACCES;
910
Josef Sipeke9536ae2006-12-08 02:37:21 -0800911 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 return -EAGAIN;
913
914 if (!(capabilities & BDI_CAP_MAP_DIRECT))
915 return -ENODEV;
916
917 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
918 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
919 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
920 ) {
921 printk("MAP_SHARED not completely supported on !MMU\n");
922 return -EINVAL;
923 }
924
925 /* we mustn't privatise shared mappings */
926 capabilities &= ~BDI_CAP_MAP_COPY;
927 }
928 else {
929 /* we're going to read the file into private memory we
930 * allocate */
931 if (!(capabilities & BDI_CAP_MAP_COPY))
932 return -ENODEV;
933
934 /* we don't permit a private writable mapping to be
935 * shared with the backing device */
936 if (prot & PROT_WRITE)
937 capabilities &= ~BDI_CAP_MAP_DIRECT;
938 }
939
940 /* handle executable mappings and implied executable
941 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800942 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 if (prot & PROT_EXEC)
944 return -EPERM;
945 }
946 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
947 /* handle implication of PROT_EXEC by PROT_READ */
948 if (current->personality & READ_IMPLIES_EXEC) {
949 if (capabilities & BDI_CAP_EXEC_MAP)
950 prot |= PROT_EXEC;
951 }
952 }
953 else if ((prot & PROT_READ) &&
954 (prot & PROT_EXEC) &&
955 !(capabilities & BDI_CAP_EXEC_MAP)
956 ) {
957 /* backing file is not executable, try to copy */
958 capabilities &= ~BDI_CAP_MAP_DIRECT;
959 }
960 }
961 else {
962 /* anonymous mappings are always memory backed and can be
963 * privately mapped
964 */
965 capabilities = BDI_CAP_MAP_COPY;
966
967 /* handle PROT_EXEC implication by PROT_READ */
968 if ((prot & PROT_READ) &&
969 (current->personality & READ_IMPLIES_EXEC))
970 prot |= PROT_EXEC;
971 }
972
973 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400974 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 if (ret < 0)
976 return ret;
977
978 /* looks okay */
979 *_capabilities = capabilities;
980 return 0;
981}
982
983/*
984 * we've determined that we can make the mapping, now translate what we
985 * now know into VMA flags
986 */
987static unsigned long determine_vm_flags(struct file *file,
988 unsigned long prot,
989 unsigned long flags,
990 unsigned long capabilities)
991{
992 unsigned long vm_flags;
993
994 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
995 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
996 /* vm_flags |= mm->def_flags; */
997
998 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
999 /* attempt to share read-only copies of mapped file chunks */
1000 if (file && !(prot & PROT_WRITE))
1001 vm_flags |= VM_MAYSHARE;
1002 }
1003 else {
1004 /* overlay a shareable mapping on the backing device or inode
1005 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1006 * romfs/cramfs */
1007 if (flags & MAP_SHARED)
1008 vm_flags |= VM_MAYSHARE | VM_SHARED;
1009 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1010 vm_flags |= VM_MAYSHARE;
1011 }
1012
1013 /* refuse to let anyone share private mappings with this process if
1014 * it's being traced - otherwise breakpoints set in it may interfere
1015 * with another untraced process
1016 */
Roland McGrathfa8e26c2008-07-25 19:45:50 -07001017 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 vm_flags &= ~VM_MAYSHARE;
1019
1020 return vm_flags;
1021}
1022
1023/*
David Howells8feae132009-01-08 12:04:47 +00001024 * set up a shared mapping on a file (the driver or filesystem provides and
1025 * pins the storage)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 */
David Howells8feae132009-01-08 12:04:47 +00001027static int do_mmap_shared_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001028{
1029 int ret;
1030
1031 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001032 if (ret == 0) {
1033 vma->vm_region->vm_top = vma->vm_region->vm_end;
1034 return ret;
1035 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 if (ret != -ENOSYS)
1037 return ret;
1038
1039 /* getting an ENOSYS error indicates that direct mmap isn't
1040 * possible (as opposed to tried but failed) so we'll fall
1041 * through to making a private copy of the data and mapping
1042 * that if we can */
1043 return -ENODEV;
1044}
1045
1046/*
1047 * set up a private mapping or an anonymous shared mapping
1048 */
David Howells8feae132009-01-08 12:04:47 +00001049static int do_mmap_private(struct vm_area_struct *vma,
1050 struct vm_region *region,
1051 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052{
David Howells8feae132009-01-08 12:04:47 +00001053 struct page *pages;
1054 unsigned long total, point, n, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001055 void *base;
David Howells8feae132009-01-08 12:04:47 +00001056 int ret, order;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001057
1058 /* invoke the file's mapping function so that it can keep track of
1059 * shared mappings on devices or memory
1060 * - VM_MAYSHARE will be set if it may attempt to share
1061 */
1062 if (vma->vm_file) {
1063 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001064 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 /* shouldn't return success if we're not sharing */
Paul Mundtdd8632a2009-01-08 12:04:47 +00001066 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1067 vma->vm_region->vm_top = vma->vm_region->vm_end;
1068 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 }
Paul Mundtdd8632a2009-01-08 12:04:47 +00001070 if (ret != -ENOSYS)
1071 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001072
1073 /* getting an ENOSYS error indicates that direct mmap isn't
1074 * possible (as opposed to tried but failed) so we'll try to
1075 * make a private copy of the data and map that instead */
1076 }
1077
David Howells8feae132009-01-08 12:04:47 +00001078 rlen = PAGE_ALIGN(len);
1079
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 /* allocate some memory to hold the mapping
1081 * - note that this may not return a page-aligned address if the object
1082 * we're allocating is smaller than a page
1083 */
David Howells8feae132009-01-08 12:04:47 +00001084 order = get_order(rlen);
1085 kdebug("alloc order %d for %lx", order, len);
1086
1087 pages = alloc_pages(GFP_KERNEL, order);
1088 if (!pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 goto enomem;
1090
David Howells8feae132009-01-08 12:04:47 +00001091 total = 1 << order;
David Howells33e5d7692009-04-02 16:56:32 -07001092 atomic_long_add(total, &mmap_pages_allocated);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
David Howells8feae132009-01-08 12:04:47 +00001094 point = rlen >> PAGE_SHIFT;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001095
1096 /* we allocated a power-of-2 sized page set, so we may want to trim off
1097 * the excess */
1098 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1099 while (total > point) {
1100 order = ilog2(total - point);
1101 n = 1 << order;
1102 kdebug("shave %lu/%lu @%lu", n, total - point, total);
David Howells33e5d7692009-04-02 16:56:32 -07001103 atomic_long_sub(n, &mmap_pages_allocated);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001104 total -= n;
1105 set_page_refcounted(pages + total);
1106 __free_pages(pages + total, order);
1107 }
David Howells8feae132009-01-08 12:04:47 +00001108 }
1109
David Howells8feae132009-01-08 12:04:47 +00001110 for (point = 1; point < total; point++)
1111 set_page_refcounted(&pages[point]);
1112
1113 base = page_address(pages);
1114 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1115 region->vm_start = (unsigned long) base;
1116 region->vm_end = region->vm_start + rlen;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001117 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
David Howells8feae132009-01-08 12:04:47 +00001118
1119 vma->vm_start = region->vm_start;
1120 vma->vm_end = region->vm_start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121
1122 if (vma->vm_file) {
1123 /* read the contents of a file into the copy */
1124 mm_segment_t old_fs;
1125 loff_t fpos;
1126
1127 fpos = vma->vm_pgoff;
1128 fpos <<= PAGE_SHIFT;
1129
1130 old_fs = get_fs();
1131 set_fs(KERNEL_DS);
David Howells8feae132009-01-08 12:04:47 +00001132 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 set_fs(old_fs);
1134
1135 if (ret < 0)
1136 goto error_free;
1137
1138 /* clear the last little bit */
David Howells8feae132009-01-08 12:04:47 +00001139 if (ret < rlen)
1140 memset(base + ret, 0, rlen - ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141
1142 } else {
1143 /* if it's an anonymous mapping, then just clear it */
David Howells8feae132009-01-08 12:04:47 +00001144 memset(base, 0, rlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001145 }
1146
1147 return 0;
1148
1149error_free:
David Howells8feae132009-01-08 12:04:47 +00001150 free_page_series(region->vm_start, region->vm_end);
1151 region->vm_start = vma->vm_start = 0;
1152 region->vm_end = vma->vm_end = 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001153 region->vm_top = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001154 return ret;
1155
1156enomem:
Greg Ungerer05ae6fa2009-01-13 17:30:22 +10001157 printk("Allocation of length %lu from process %d (%s) failed\n",
1158 len, current->pid, current->comm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001159 show_free_areas();
1160 return -ENOMEM;
1161}
1162
1163/*
1164 * handle mapping creation for uClinux
1165 */
1166unsigned long do_mmap_pgoff(struct file *file,
1167 unsigned long addr,
1168 unsigned long len,
1169 unsigned long prot,
1170 unsigned long flags,
1171 unsigned long pgoff)
1172{
David Howells8feae132009-01-08 12:04:47 +00001173 struct vm_area_struct *vma;
1174 struct vm_region *region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 struct rb_node *rb;
David Howells8feae132009-01-08 12:04:47 +00001176 unsigned long capabilities, vm_flags, result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 int ret;
1178
David Howells8feae132009-01-08 12:04:47 +00001179 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1180
Eric Paris7cd94142007-11-26 18:47:40 -05001181 if (!(flags & MAP_FIXED))
1182 addr = round_hint_to_min(addr);
1183
Linus Torvalds1da177e2005-04-16 15:20:36 -07001184 /* decide whether we should attempt the mapping, and if so what sort of
1185 * mapping */
1186 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1187 &capabilities);
David Howells8feae132009-01-08 12:04:47 +00001188 if (ret < 0) {
1189 kleave(" = %d [val]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 return ret;
David Howells8feae132009-01-08 12:04:47 +00001191 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001192
1193 /* we've determined that we can make the mapping, now translate what we
1194 * now know into VMA flags */
1195 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1196
David Howells8feae132009-01-08 12:04:47 +00001197 /* we're going to need to record the mapping */
1198 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1199 if (!region)
1200 goto error_getting_region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001201
David Howells8feae132009-01-08 12:04:47 +00001202 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1203 if (!vma)
1204 goto error_getting_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205
David Howells8feae132009-01-08 12:04:47 +00001206 atomic_set(&region->vm_usage, 1);
1207 region->vm_flags = vm_flags;
1208 region->vm_pgoff = pgoff;
1209
1210 INIT_LIST_HEAD(&vma->anon_vma_node);
1211 vma->vm_flags = vm_flags;
1212 vma->vm_pgoff = pgoff;
1213
1214 if (file) {
1215 region->vm_file = file;
1216 get_file(file);
1217 vma->vm_file = file;
1218 get_file(file);
1219 if (vm_flags & VM_EXECUTABLE) {
1220 added_exe_file_vma(current->mm);
1221 vma->vm_mm = current->mm;
1222 }
1223 }
1224
1225 down_write(&nommu_region_sem);
1226
1227 /* if we want to share, we need to check for regions created by other
Linus Torvalds1da177e2005-04-16 15:20:36 -07001228 * mmap() calls that overlap with our proposed mapping
David Howells8feae132009-01-08 12:04:47 +00001229 * - we can only share with a superset match on most regular files
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230 * - shared mappings on character devices and memory backed files are
1231 * permitted to overlap inexactly as far as we are concerned for in
1232 * these cases, sharing is handled in the driver or filesystem rather
1233 * than here
1234 */
1235 if (vm_flags & VM_MAYSHARE) {
David Howells8feae132009-01-08 12:04:47 +00001236 struct vm_region *pregion;
1237 unsigned long pglen, rpglen, pgend, rpgend, start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238
David Howells8feae132009-01-08 12:04:47 +00001239 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1240 pgend = pgoff + pglen;
David Howells165b2392007-03-22 00:11:24 -08001241
David Howells8feae132009-01-08 12:04:47 +00001242 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1243 pregion = rb_entry(rb, struct vm_region, vm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001244
David Howells8feae132009-01-08 12:04:47 +00001245 if (!(pregion->vm_flags & VM_MAYSHARE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001246 continue;
1247
1248 /* search for overlapping mappings on the same file */
David Howells8feae132009-01-08 12:04:47 +00001249 if (pregion->vm_file->f_path.dentry->d_inode !=
1250 file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 continue;
1252
David Howells8feae132009-01-08 12:04:47 +00001253 if (pregion->vm_pgoff >= pgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 continue;
1255
David Howells8feae132009-01-08 12:04:47 +00001256 rpglen = pregion->vm_end - pregion->vm_start;
1257 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1258 rpgend = pregion->vm_pgoff + rpglen;
1259 if (pgoff >= rpgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260 continue;
1261
David Howells8feae132009-01-08 12:04:47 +00001262 /* handle inexactly overlapping matches between
1263 * mappings */
1264 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1265 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1266 /* new mapping is not a subset of the region */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1268 goto sharing_violation;
1269 continue;
1270 }
1271
David Howells8feae132009-01-08 12:04:47 +00001272 /* we've found a region we can share */
1273 atomic_inc(&pregion->vm_usage);
1274 vma->vm_region = pregion;
1275 start = pregion->vm_start;
1276 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1277 vma->vm_start = start;
1278 vma->vm_end = start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279
David Howells8feae132009-01-08 12:04:47 +00001280 if (pregion->vm_flags & VM_MAPPED_COPY) {
1281 kdebug("share copy");
1282 vma->vm_flags |= VM_MAPPED_COPY;
1283 } else {
1284 kdebug("share mmap");
1285 ret = do_mmap_shared_file(vma);
1286 if (ret < 0) {
1287 vma->vm_region = NULL;
1288 vma->vm_start = 0;
1289 vma->vm_end = 0;
1290 atomic_dec(&pregion->vm_usage);
1291 pregion = NULL;
1292 goto error_just_free;
1293 }
1294 }
1295 fput(region->vm_file);
1296 kmem_cache_free(vm_region_jar, region);
1297 region = pregion;
1298 result = start;
1299 goto share;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 }
1301
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302 /* obtain the address at which to make a shared mapping
1303 * - this is the hook for quasi-memory character devices to
1304 * tell us the location of a shared mapping
1305 */
1306 if (file && file->f_op->get_unmapped_area) {
1307 addr = file->f_op->get_unmapped_area(file, addr, len,
1308 pgoff, flags);
1309 if (IS_ERR((void *) addr)) {
1310 ret = addr;
1311 if (ret != (unsigned long) -ENOSYS)
David Howells8feae132009-01-08 12:04:47 +00001312 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313
1314 /* the driver refused to tell us where to site
1315 * the mapping so we'll have to attempt to copy
1316 * it */
1317 ret = (unsigned long) -ENODEV;
1318 if (!(capabilities & BDI_CAP_MAP_COPY))
David Howells8feae132009-01-08 12:04:47 +00001319 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001320
1321 capabilities &= ~BDI_CAP_MAP_DIRECT;
David Howells8feae132009-01-08 12:04:47 +00001322 } else {
1323 vma->vm_start = region->vm_start = addr;
1324 vma->vm_end = region->vm_end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 }
1326 }
1327 }
1328
David Howells8feae132009-01-08 12:04:47 +00001329 vma->vm_region = region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001330
1331 /* set up the mapping */
1332 if (file && vma->vm_flags & VM_SHARED)
David Howells8feae132009-01-08 12:04:47 +00001333 ret = do_mmap_shared_file(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001334 else
David Howells8feae132009-01-08 12:04:47 +00001335 ret = do_mmap_private(vma, region, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 if (ret < 0)
David Howells8feae132009-01-08 12:04:47 +00001337 goto error_put_region;
1338
1339 add_nommu_region(region);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340
1341 /* okay... we have a mapping; now we have to register it */
David Howells8feae132009-01-08 12:04:47 +00001342 result = vma->vm_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344 current->mm->total_vm += len >> PAGE_SHIFT;
1345
David Howells8feae132009-01-08 12:04:47 +00001346share:
1347 add_vma_to_mm(current->mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348
David Howells8feae132009-01-08 12:04:47 +00001349 up_write(&nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350
1351 if (prot & PROT_EXEC)
David Howells8feae132009-01-08 12:04:47 +00001352 flush_icache_range(result, result + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353
David Howells8feae132009-01-08 12:04:47 +00001354 kleave(" = %lx", result);
1355 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356
David Howells8feae132009-01-08 12:04:47 +00001357error_put_region:
1358 __put_nommu_region(region);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001359 if (vma) {
Matt Helsley925d1c42008-04-29 01:01:36 -07001360 if (vma->vm_file) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -07001361 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001362 if (vma->vm_flags & VM_EXECUTABLE)
1363 removed_exe_file_vma(vma->vm_mm);
1364 }
David Howells8feae132009-01-08 12:04:47 +00001365 kmem_cache_free(vm_area_cachep, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001366 }
David Howells8feae132009-01-08 12:04:47 +00001367 kleave(" = %d [pr]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 return ret;
1369
David Howells8feae132009-01-08 12:04:47 +00001370error_just_free:
1371 up_write(&nommu_region_sem);
1372error:
1373 fput(region->vm_file);
1374 kmem_cache_free(vm_region_jar, region);
1375 fput(vma->vm_file);
1376 if (vma->vm_flags & VM_EXECUTABLE)
1377 removed_exe_file_vma(vma->vm_mm);
1378 kmem_cache_free(vm_area_cachep, vma);
1379 kleave(" = %d", ret);
1380 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381
David Howells8feae132009-01-08 12:04:47 +00001382sharing_violation:
1383 up_write(&nommu_region_sem);
1384 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1385 ret = -EINVAL;
1386 goto error;
1387
1388error_getting_vma:
1389 kmem_cache_free(vm_region_jar, region);
1390 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1391 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001392 len, current->pid);
1393 show_free_areas();
1394 return -ENOMEM;
1395
David Howells8feae132009-01-08 12:04:47 +00001396error_getting_region:
1397 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1398 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001399 len, current->pid);
1400 show_free_areas();
1401 return -ENOMEM;
1402}
Paul Mundtb5073172007-07-21 04:37:25 -07001403EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404
1405/*
David Howells8feae132009-01-08 12:04:47 +00001406 * split a vma into two pieces at address 'addr', a new vma is allocated either
1407 * for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 */
David Howells8feae132009-01-08 12:04:47 +00001409int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1410 unsigned long addr, int new_below)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411{
David Howells8feae132009-01-08 12:04:47 +00001412 struct vm_area_struct *new;
1413 struct vm_region *region;
1414 unsigned long npages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
David Howells8feae132009-01-08 12:04:47 +00001416 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417
David Howells8feae132009-01-08 12:04:47 +00001418 /* we're only permitted to split anonymous regions that have a single
1419 * owner */
1420 if (vma->vm_file ||
1421 atomic_read(&vma->vm_region->vm_usage) != 1)
1422 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001423
David Howells8feae132009-01-08 12:04:47 +00001424 if (mm->map_count >= sysctl_max_map_count)
1425 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426
David Howells8feae132009-01-08 12:04:47 +00001427 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1428 if (!region)
1429 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430
David Howells8feae132009-01-08 12:04:47 +00001431 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1432 if (!new) {
1433 kmem_cache_free(vm_region_jar, region);
1434 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435 }
David Howells8feae132009-01-08 12:04:47 +00001436
1437 /* most fields are the same, copy all, and then fixup */
1438 *new = *vma;
1439 *region = *vma->vm_region;
1440 new->vm_region = region;
1441
1442 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1443
1444 if (new_below) {
Paul Mundtdd8632a2009-01-08 12:04:47 +00001445 region->vm_top = region->vm_end = new->vm_end = addr;
David Howells8feae132009-01-08 12:04:47 +00001446 } else {
1447 region->vm_start = new->vm_start = addr;
1448 region->vm_pgoff = new->vm_pgoff += npages;
1449 }
1450
1451 if (new->vm_ops && new->vm_ops->open)
1452 new->vm_ops->open(new);
1453
1454 delete_vma_from_mm(vma);
1455 down_write(&nommu_region_sem);
1456 delete_nommu_region(vma->vm_region);
1457 if (new_below) {
1458 vma->vm_region->vm_start = vma->vm_start = addr;
1459 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1460 } else {
1461 vma->vm_region->vm_end = vma->vm_end = addr;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001462 vma->vm_region->vm_top = addr;
David Howells8feae132009-01-08 12:04:47 +00001463 }
1464 add_nommu_region(vma->vm_region);
1465 add_nommu_region(new->vm_region);
1466 up_write(&nommu_region_sem);
1467 add_vma_to_mm(mm, vma);
1468 add_vma_to_mm(mm, new);
1469 return 0;
1470}
1471
1472/*
1473 * shrink a VMA by removing the specified chunk from either the beginning or
1474 * the end
1475 */
1476static int shrink_vma(struct mm_struct *mm,
1477 struct vm_area_struct *vma,
1478 unsigned long from, unsigned long to)
1479{
1480 struct vm_region *region;
1481
1482 kenter("");
1483
1484 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1485 * and list */
1486 delete_vma_from_mm(vma);
1487 if (from > vma->vm_start)
1488 vma->vm_end = from;
1489 else
1490 vma->vm_start = to;
1491 add_vma_to_mm(mm, vma);
1492
1493 /* cut the backing region down to size */
1494 region = vma->vm_region;
1495 BUG_ON(atomic_read(&region->vm_usage) != 1);
1496
1497 down_write(&nommu_region_sem);
1498 delete_nommu_region(region);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001499 if (from > region->vm_start) {
1500 to = region->vm_top;
1501 region->vm_top = region->vm_end = from;
1502 } else {
David Howells8feae132009-01-08 12:04:47 +00001503 region->vm_start = to;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001504 }
David Howells8feae132009-01-08 12:04:47 +00001505 add_nommu_region(region);
1506 up_write(&nommu_region_sem);
1507
1508 free_page_series(from, to);
1509 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510}
1511
David Howells30340972006-09-27 01:50:20 -07001512/*
1513 * release a mapping
David Howells8feae132009-01-08 12:04:47 +00001514 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1515 * VMA, though it need not cover the whole VMA
David Howells30340972006-09-27 01:50:20 -07001516 */
David Howells8feae132009-01-08 12:04:47 +00001517int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001518{
David Howells8feae132009-01-08 12:04:47 +00001519 struct vm_area_struct *vma;
1520 struct rb_node *rb;
1521 unsigned long end = start + len;
1522 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523
David Howells8feae132009-01-08 12:04:47 +00001524 kenter(",%lx,%zx", start, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525
David Howells8feae132009-01-08 12:04:47 +00001526 if (len == 0)
1527 return -EINVAL;
1528
1529 /* find the first potentially overlapping VMA */
1530 vma = find_vma(mm, start);
1531 if (!vma) {
David Howells33e5d7692009-04-02 16:56:32 -07001532 static int limit = 0;
1533 if (limit < 5) {
1534 printk(KERN_WARNING
1535 "munmap of memory not mmapped by process %d"
1536 " (%s): 0x%lx-0x%lx\n",
1537 current->pid, current->comm,
1538 start, start + len - 1);
1539 limit++;
1540 }
David Howells8feae132009-01-08 12:04:47 +00001541 return -EINVAL;
David Howells30340972006-09-27 01:50:20 -07001542 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001543
David Howells8feae132009-01-08 12:04:47 +00001544 /* we're allowed to split an anonymous VMA but not a file-backed one */
1545 if (vma->vm_file) {
1546 do {
1547 if (start > vma->vm_start) {
1548 kleave(" = -EINVAL [miss]");
1549 return -EINVAL;
1550 }
1551 if (end == vma->vm_end)
1552 goto erase_whole_vma;
1553 rb = rb_next(&vma->vm_rb);
1554 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1555 } while (rb);
1556 kleave(" = -EINVAL [split file]");
1557 return -EINVAL;
1558 } else {
1559 /* the chunk must be a subset of the VMA found */
1560 if (start == vma->vm_start && end == vma->vm_end)
1561 goto erase_whole_vma;
1562 if (start < vma->vm_start || end > vma->vm_end) {
1563 kleave(" = -EINVAL [superset]");
1564 return -EINVAL;
1565 }
1566 if (start & ~PAGE_MASK) {
1567 kleave(" = -EINVAL [unaligned start]");
1568 return -EINVAL;
1569 }
1570 if (end != vma->vm_end && end & ~PAGE_MASK) {
1571 kleave(" = -EINVAL [unaligned split]");
1572 return -EINVAL;
1573 }
1574 if (start != vma->vm_start && end != vma->vm_end) {
1575 ret = split_vma(mm, vma, start, 1);
1576 if (ret < 0) {
1577 kleave(" = %d [split]", ret);
1578 return ret;
1579 }
1580 }
1581 return shrink_vma(mm, vma, start, end);
1582 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583
David Howells8feae132009-01-08 12:04:47 +00001584erase_whole_vma:
1585 delete_vma_from_mm(vma);
1586 delete_vma(mm, vma);
1587 kleave(" = 0");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588 return 0;
1589}
Paul Mundtb5073172007-07-21 04:37:25 -07001590EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001591
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001592SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
David Howells30340972006-09-27 01:50:20 -07001593{
1594 int ret;
1595 struct mm_struct *mm = current->mm;
1596
1597 down_write(&mm->mmap_sem);
1598 ret = do_munmap(mm, addr, len);
1599 up_write(&mm->mmap_sem);
1600 return ret;
1601}
1602
1603/*
David Howells8feae132009-01-08 12:04:47 +00001604 * release all the mappings made in a process's VM space
David Howells30340972006-09-27 01:50:20 -07001605 */
David Howells8feae132009-01-08 12:04:47 +00001606void exit_mmap(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001607{
David Howells8feae132009-01-08 12:04:47 +00001608 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001609
David Howells8feae132009-01-08 12:04:47 +00001610 if (!mm)
1611 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001612
David Howells8feae132009-01-08 12:04:47 +00001613 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001614
David Howells8feae132009-01-08 12:04:47 +00001615 mm->total_vm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001616
David Howells8feae132009-01-08 12:04:47 +00001617 while ((vma = mm->mmap)) {
1618 mm->mmap = vma->vm_next;
1619 delete_vma_from_mm(vma);
1620 delete_vma(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001621 }
David Howells8feae132009-01-08 12:04:47 +00001622
1623 kleave("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624}
1625
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626unsigned long do_brk(unsigned long addr, unsigned long len)
1627{
1628 return -ENOMEM;
1629}
1630
1631/*
David Howells6fa5f802006-09-27 01:50:21 -07001632 * expand (or shrink) an existing mapping, potentially moving it at the same
1633 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001634 *
David Howells6fa5f802006-09-27 01:50:21 -07001635 * under NOMMU conditions, we only permit changing a mapping's size, and only
David Howells8feae132009-01-08 12:04:47 +00001636 * as long as it stays within the region allocated by do_mmap_private() and the
1637 * block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638 *
David Howells6fa5f802006-09-27 01:50:21 -07001639 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001640 */
1641unsigned long do_mremap(unsigned long addr,
1642 unsigned long old_len, unsigned long new_len,
1643 unsigned long flags, unsigned long new_addr)
1644{
David Howells6fa5f802006-09-27 01:50:21 -07001645 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646
1647 /* insanity checks first */
David Howells8feae132009-01-08 12:04:47 +00001648 if (old_len == 0 || new_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649 return (unsigned long) -EINVAL;
1650
David Howells8feae132009-01-08 12:04:47 +00001651 if (addr & ~PAGE_MASK)
1652 return -EINVAL;
1653
Linus Torvalds1da177e2005-04-16 15:20:36 -07001654 if (flags & MREMAP_FIXED && new_addr != addr)
1655 return (unsigned long) -EINVAL;
1656
David Howells8feae132009-01-08 12:04:47 +00001657 vma = find_vma_exact(current->mm, addr, old_len);
David Howells6fa5f802006-09-27 01:50:21 -07001658 if (!vma)
1659 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001660
David Howells6fa5f802006-09-27 01:50:21 -07001661 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001662 return (unsigned long) -EFAULT;
1663
David Howells6fa5f802006-09-27 01:50:21 -07001664 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001665 return (unsigned long) -EPERM;
1666
David Howells8feae132009-01-08 12:04:47 +00001667 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001668 return (unsigned long) -ENOMEM;
1669
1670 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001671 vma->vm_end = vma->vm_start + new_len;
David Howells6fa5f802006-09-27 01:50:21 -07001672 return vma->vm_start;
1673}
Paul Mundtb5073172007-07-21 04:37:25 -07001674EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001675
Heiko Carstens6a6160a2009-01-14 14:14:15 +01001676SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1677 unsigned long, new_len, unsigned long, flags,
1678 unsigned long, new_addr)
David Howells6fa5f802006-09-27 01:50:21 -07001679{
1680 unsigned long ret;
1681
1682 down_write(&current->mm->mmap_sem);
1683 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1684 up_write(&current->mm->mmap_sem);
1685 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001686}
1687
Linus Torvalds6aab3412005-11-28 14:34:23 -08001688struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001689 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690{
1691 return NULL;
1692}
1693
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1695 unsigned long to, unsigned long size, pgprot_t prot)
1696{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001697 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1698 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699}
Luke Yang22c4af42006-07-14 00:24:09 -07001700EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701
Paul Mundtf905bc42008-02-04 22:29:59 -08001702int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1703 unsigned long pgoff)
1704{
1705 unsigned int size = vma->vm_end - vma->vm_start;
1706
1707 if (!(vma->vm_flags & VM_USERMAP))
1708 return -EINVAL;
1709
1710 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1711 vma->vm_end = vma->vm_start + size;
1712
1713 return 0;
1714}
1715EXPORT_SYMBOL(remap_vmalloc_range);
1716
Linus Torvalds1da177e2005-04-16 15:20:36 -07001717void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1718{
1719}
1720
1721unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1722 unsigned long len, unsigned long pgoff, unsigned long flags)
1723{
1724 return -ENOMEM;
1725}
1726
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001727void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728{
1729}
1730
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731void unmap_mapping_range(struct address_space *mapping,
1732 loff_t const holebegin, loff_t const holelen,
1733 int even_cows)
1734{
1735}
Luke Yang22c4af42006-07-14 00:24:09 -07001736EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737
1738/*
David Howellsd56e03c2007-03-22 00:11:23 -08001739 * ask for an unmapped area at which to create a mapping on a file
1740 */
1741unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1742 unsigned long len, unsigned long pgoff,
1743 unsigned long flags)
1744{
1745 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1746 unsigned long, unsigned long);
1747
1748 get_area = current->mm->get_unmapped_area;
1749 if (file && file->f_op && file->f_op->get_unmapped_area)
1750 get_area = file->f_op->get_unmapped_area;
1751
1752 if (!get_area)
1753 return -ENOSYS;
1754
1755 return get_area(file, addr, len, pgoff, flags);
1756}
David Howellsd56e03c2007-03-22 00:11:23 -08001757EXPORT_SYMBOL(get_unmapped_area);
1758
1759/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 * Check that a process has enough memory to allocate a new virtual
1761 * mapping. 0 means there is enough memory for the allocation to
1762 * succeed and -ENOMEM implies there is not.
1763 *
1764 * We currently support three overcommit policies, which are set via the
1765 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1766 *
1767 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1768 * Additional code 2002 Jul 20 by Robert Love.
1769 *
1770 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1771 *
1772 * Note this is a helper function intended to be used by LSMs which
1773 * wish to use this logic.
1774 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001775int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776{
1777 unsigned long free, allowed;
1778
1779 vm_acct_memory(pages);
1780
1781 /*
1782 * Sometimes we want to use more memory than we have
1783 */
1784 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1785 return 0;
1786
1787 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1788 unsigned long n;
1789
Christoph Lameter347ce432006-06-30 01:55:35 -07001790 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 free += nr_swap_pages;
1792
1793 /*
1794 * Any slabs which are created with the
1795 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1796 * which are reclaimable, under pressure. The dentry
1797 * cache and most inode caches should fall into this
1798 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001799 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800
1801 /*
1802 * Leave the last 3% for root
1803 */
1804 if (!cap_sys_admin)
1805 free -= free / 32;
1806
1807 if (free > pages)
1808 return 0;
1809
1810 /*
1811 * nr_free_pages() is very expensive on large systems,
1812 * only call if we're about to fail.
1813 */
1814 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001815
1816 /*
1817 * Leave reserved pages. The pages are not for anonymous pages.
1818 */
1819 if (n <= totalreserve_pages)
1820 goto error;
1821 else
1822 n -= totalreserve_pages;
1823
1824 /*
1825 * Leave the last 3% for root
1826 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001827 if (!cap_sys_admin)
1828 n -= n / 32;
1829 free += n;
1830
1831 if (free > pages)
1832 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001833
1834 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001835 }
1836
1837 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1838 /*
1839 * Leave the last 3% for root
1840 */
1841 if (!cap_sys_admin)
1842 allowed -= allowed / 32;
1843 allowed += total_swap_pages;
1844
1845 /* Don't let a single process grow too big:
1846 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -07001847 if (mm)
1848 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849
Simon Derr2f60f8d2005-08-04 19:52:03 -07001850 /*
1851 * cast `allowed' as a signed long because vm_committed_space
1852 * sometimes has a negative value
1853 */
Alan Cox80119ef2008-05-23 13:04:31 -07001854 if (atomic_long_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001855 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001856error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001857 vm_unacct_memory(pages);
1858
1859 return -ENOMEM;
1860}
1861
1862int in_gate_area_no_task(unsigned long addr)
1863{
1864 return 0;
1865}
David Howellsb0e15192006-01-06 00:11:42 -08001866
Nick Piggind0217ac2007-07-19 01:47:03 -07001867int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001868{
1869 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001870 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001871}
Paul Mundtb5073172007-07-21 04:37:25 -07001872EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001873
1874/*
1875 * Access another process' address space.
1876 * - source/target buffer must be kernel space
1877 */
1878int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1879{
David Howells0ec76a12006-09-27 01:50:15 -07001880 struct vm_area_struct *vma;
1881 struct mm_struct *mm;
1882
1883 if (addr + len < addr)
1884 return 0;
1885
1886 mm = get_task_mm(tsk);
1887 if (!mm)
1888 return 0;
1889
1890 down_read(&mm->mmap_sem);
1891
1892 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001893 vma = find_vma(mm, addr);
1894 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001895 /* don't overrun this mapping */
1896 if (addr + len >= vma->vm_end)
1897 len = vma->vm_end - addr;
1898
1899 /* only read or write mappings where it is permitted */
David Howellsd00c7b92006-09-27 01:50:19 -07001900 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001901 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b92006-09-27 01:50:19 -07001902 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001903 len -= copy_from_user(buf, (void *) addr, len);
1904 else
1905 len = 0;
1906 } else {
1907 len = 0;
1908 }
1909
1910 up_read(&mm->mmap_sem);
1911 mmput(mm);
1912 return len;
1913}