blob: 60ed8375c986f56604e1551836fcf0f48d1273a3 [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 Mundtdd8632a2009-01-08 12:04:47 +000013 * Copyright (c) 2007-2008 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 Howells8feae132009-01-08 12:04:47 +000072atomic_t mmap_pages_allocated;
73
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,
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
397/*
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700398 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
399 * have one.
400 */
401void __attribute__((weak)) vmalloc_sync_all(void)
402{
403}
404
Paul Mundtb5073172007-07-21 04:37:25 -0700405int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
406 struct page *page)
407{
408 return -EINVAL;
409}
410EXPORT_SYMBOL(vm_insert_page);
411
Christoph Hellwig1eeb66a2007-05-08 00:27:03 -0700412/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 * sys_brk() for the most part doesn't need the global kernel
414 * lock, except when an application is doing something nasty
415 * like trying to un-brk an area that has already been mapped
416 * to a regular file. in this case, the unmapping will need
417 * to invoke file system routines that need the global lock.
418 */
419asmlinkage unsigned long sys_brk(unsigned long brk)
420{
421 struct mm_struct *mm = current->mm;
422
423 if (brk < mm->start_brk || brk > mm->context.end_brk)
424 return mm->brk;
425
426 if (mm->brk == brk)
427 return mm->brk;
428
429 /*
430 * Always allow shrinking brk
431 */
432 if (brk <= mm->brk) {
433 mm->brk = brk;
434 return brk;
435 }
436
437 /*
438 * Ok, looks good - let it rip.
439 */
440 return mm->brk = brk;
441}
442
David Howells8feae132009-01-08 12:04:47 +0000443/*
444 * initialise the VMA and region record slabs
445 */
446void __init mmap_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447{
David Howells8feae132009-01-08 12:04:47 +0000448 vm_region_jar = kmem_cache_create("vm_region_jar",
449 sizeof(struct vm_region), 0,
450 SLAB_PANIC, NULL);
451 vm_area_cachep = kmem_cache_create("vm_area_struct",
452 sizeof(struct vm_area_struct), 0,
453 SLAB_PANIC, NULL);
454}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455
David Howells8feae132009-01-08 12:04:47 +0000456/*
457 * validate the region tree
458 * - the caller must hold the region lock
459 */
460#ifdef CONFIG_DEBUG_NOMMU_REGIONS
461static noinline void validate_nommu_regions(void)
462{
463 struct vm_region *region, *last;
464 struct rb_node *p, *lastp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465
David Howells8feae132009-01-08 12:04:47 +0000466 lastp = rb_first(&nommu_region_tree);
467 if (!lastp)
468 return;
469
470 last = rb_entry(lastp, struct vm_region, vm_rb);
471 if (unlikely(last->vm_end <= last->vm_start))
472 BUG();
Paul Mundtdd8632a2009-01-08 12:04:47 +0000473 if (unlikely(last->vm_top < last->vm_end))
474 BUG();
David Howells8feae132009-01-08 12:04:47 +0000475
476 while ((p = rb_next(lastp))) {
477 region = rb_entry(p, struct vm_region, vm_rb);
478 last = rb_entry(lastp, struct vm_region, vm_rb);
479
480 if (unlikely(region->vm_end <= region->vm_start))
481 BUG();
Paul Mundtdd8632a2009-01-08 12:04:47 +0000482 if (unlikely(region->vm_top < region->vm_end))
483 BUG();
484 if (unlikely(region->vm_start < last->vm_top))
David Howells8feae132009-01-08 12:04:47 +0000485 BUG();
486
487 lastp = p;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 }
489}
David Howells8feae132009-01-08 12:04:47 +0000490#else
491#define validate_nommu_regions() do {} while(0)
492#endif
493
494/*
495 * add a region into the global tree
496 */
497static void add_nommu_region(struct vm_region *region)
498{
499 struct vm_region *pregion;
500 struct rb_node **p, *parent;
501
502 validate_nommu_regions();
503
504 BUG_ON(region->vm_start & ~PAGE_MASK);
505
506 parent = NULL;
507 p = &nommu_region_tree.rb_node;
508 while (*p) {
509 parent = *p;
510 pregion = rb_entry(parent, struct vm_region, vm_rb);
511 if (region->vm_start < pregion->vm_start)
512 p = &(*p)->rb_left;
513 else if (region->vm_start > pregion->vm_start)
514 p = &(*p)->rb_right;
515 else if (pregion == region)
516 return;
517 else
518 BUG();
519 }
520
521 rb_link_node(&region->vm_rb, parent, p);
522 rb_insert_color(&region->vm_rb, &nommu_region_tree);
523
524 validate_nommu_regions();
525}
526
527/*
528 * delete a region from the global tree
529 */
530static void delete_nommu_region(struct vm_region *region)
531{
532 BUG_ON(!nommu_region_tree.rb_node);
533
534 validate_nommu_regions();
535 rb_erase(&region->vm_rb, &nommu_region_tree);
536 validate_nommu_regions();
537}
538
539/*
540 * free a contiguous series of pages
541 */
542static void free_page_series(unsigned long from, unsigned long to)
543{
544 for (; from < to; from += PAGE_SIZE) {
545 struct page *page = virt_to_page(from);
546
547 kdebug("- free %lx", from);
548 atomic_dec(&mmap_pages_allocated);
549 if (page_count(page) != 1)
550 kdebug("free page %p [%d]", page, page_count(page));
551 put_page(page);
552 }
553}
554
555/*
556 * release a reference to a region
557 * - the caller must hold the region semaphore, which this releases
Paul Mundtdd8632a2009-01-08 12:04:47 +0000558 * - the region may not have been added to the tree yet, in which case vm_top
David Howells8feae132009-01-08 12:04:47 +0000559 * will equal vm_start
560 */
561static void __put_nommu_region(struct vm_region *region)
562 __releases(nommu_region_sem)
563{
564 kenter("%p{%d}", region, atomic_read(&region->vm_usage));
565
566 BUG_ON(!nommu_region_tree.rb_node);
567
568 if (atomic_dec_and_test(&region->vm_usage)) {
Paul Mundtdd8632a2009-01-08 12:04:47 +0000569 if (region->vm_top > region->vm_start)
David Howells8feae132009-01-08 12:04:47 +0000570 delete_nommu_region(region);
571 up_write(&nommu_region_sem);
572
573 if (region->vm_file)
574 fput(region->vm_file);
575
576 /* IO memory and memory shared directly out of the pagecache
577 * from ramfs/tmpfs mustn't be released here */
578 if (region->vm_flags & VM_MAPPED_COPY) {
579 kdebug("free series");
Paul Mundtdd8632a2009-01-08 12:04:47 +0000580 free_page_series(region->vm_start, region->vm_top);
David Howells8feae132009-01-08 12:04:47 +0000581 }
582 kmem_cache_free(vm_region_jar, region);
583 } else {
584 up_write(&nommu_region_sem);
585 }
586}
587
588/*
589 * release a reference to a region
590 */
591static void put_nommu_region(struct vm_region *region)
592{
593 down_write(&nommu_region_sem);
594 __put_nommu_region(region);
595}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596
David Howells30340972006-09-27 01:50:20 -0700597/*
598 * add a VMA into a process's mm_struct in the appropriate place in the list
David Howells8feae132009-01-08 12:04:47 +0000599 * and tree and add to the address space's page tree also if not an anonymous
600 * page
David Howells30340972006-09-27 01:50:20 -0700601 * - should be called with mm->mmap_sem held writelocked
602 */
David Howells8feae132009-01-08 12:04:47 +0000603static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
David Howells30340972006-09-27 01:50:20 -0700604{
David Howells8feae132009-01-08 12:04:47 +0000605 struct vm_area_struct *pvma, **pp;
606 struct address_space *mapping;
607 struct rb_node **p, *parent;
David Howells30340972006-09-27 01:50:20 -0700608
David Howells8feae132009-01-08 12:04:47 +0000609 kenter(",%p", vma);
610
611 BUG_ON(!vma->vm_region);
612
613 mm->map_count++;
614 vma->vm_mm = mm;
615
616 /* add the VMA to the mapping */
617 if (vma->vm_file) {
618 mapping = vma->vm_file->f_mapping;
619
620 flush_dcache_mmap_lock(mapping);
621 vma_prio_tree_insert(vma, &mapping->i_mmap);
622 flush_dcache_mmap_unlock(mapping);
623 }
624
625 /* add the VMA to the tree */
626 parent = NULL;
627 p = &mm->mm_rb.rb_node;
628 while (*p) {
629 parent = *p;
630 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
631
632 /* sort by: start addr, end addr, VMA struct addr in that order
633 * (the latter is necessary as we may get identical VMAs) */
634 if (vma->vm_start < pvma->vm_start)
635 p = &(*p)->rb_left;
636 else if (vma->vm_start > pvma->vm_start)
637 p = &(*p)->rb_right;
638 else if (vma->vm_end < pvma->vm_end)
639 p = &(*p)->rb_left;
640 else if (vma->vm_end > pvma->vm_end)
641 p = &(*p)->rb_right;
642 else if (vma < pvma)
643 p = &(*p)->rb_left;
644 else if (vma > pvma)
645 p = &(*p)->rb_right;
646 else
647 BUG();
648 }
649
650 rb_link_node(&vma->vm_rb, parent, p);
651 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
652
653 /* add VMA to the VMA list also */
654 for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
655 if (pvma->vm_start > vma->vm_start)
David Howells30340972006-09-27 01:50:20 -0700656 break;
David Howells8feae132009-01-08 12:04:47 +0000657 if (pvma->vm_start < vma->vm_start)
658 continue;
659 if (pvma->vm_end < vma->vm_end)
660 break;
661 }
David Howells30340972006-09-27 01:50:20 -0700662
David Howells8feae132009-01-08 12:04:47 +0000663 vma->vm_next = *pp;
664 *pp = vma;
665}
666
667/*
668 * delete a VMA from its owning mm_struct and address space
669 */
670static void delete_vma_from_mm(struct vm_area_struct *vma)
671{
672 struct vm_area_struct **pp;
673 struct address_space *mapping;
674 struct mm_struct *mm = vma->vm_mm;
675
676 kenter("%p", vma);
677
678 mm->map_count--;
679 if (mm->mmap_cache == vma)
680 mm->mmap_cache = NULL;
681
682 /* remove the VMA from the mapping */
683 if (vma->vm_file) {
684 mapping = vma->vm_file->f_mapping;
685
686 flush_dcache_mmap_lock(mapping);
687 vma_prio_tree_remove(vma, &mapping->i_mmap);
688 flush_dcache_mmap_unlock(mapping);
689 }
690
691 /* remove from the MM's tree and list */
692 rb_erase(&vma->vm_rb, &mm->mm_rb);
693 for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
694 if (*pp == vma) {
695 *pp = vma->vm_next;
696 break;
697 }
698 }
699
700 vma->vm_mm = NULL;
701}
702
703/*
704 * destroy a VMA record
705 */
706static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
707{
708 kenter("%p", vma);
709 if (vma->vm_ops && vma->vm_ops->close)
710 vma->vm_ops->close(vma);
711 if (vma->vm_file) {
712 fput(vma->vm_file);
713 if (vma->vm_flags & VM_EXECUTABLE)
714 removed_exe_file_vma(mm);
715 }
716 put_nommu_region(vma->vm_region);
717 kmem_cache_free(vm_area_cachep, vma);
David Howells30340972006-09-27 01:50:20 -0700718}
719
720/*
721 * look up the first VMA in which addr resides, NULL if none
722 * - should be called with mm->mmap_sem at least held readlocked
723 */
724struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
725{
David Howells8feae132009-01-08 12:04:47 +0000726 struct vm_area_struct *vma;
727 struct rb_node *n = mm->mm_rb.rb_node;
David Howells30340972006-09-27 01:50:20 -0700728
David Howells8feae132009-01-08 12:04:47 +0000729 /* check the cache first */
730 vma = mm->mmap_cache;
731 if (vma && vma->vm_start <= addr && vma->vm_end > addr)
732 return vma;
733
734 /* trawl the tree (there may be multiple mappings in which addr
735 * resides) */
736 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
737 vma = rb_entry(n, struct vm_area_struct, vm_rb);
738 if (vma->vm_start > addr)
739 return NULL;
740 if (vma->vm_end > addr) {
741 mm->mmap_cache = vma;
742 return vma;
743 }
David Howells30340972006-09-27 01:50:20 -0700744 }
745
David Howells30340972006-09-27 01:50:20 -0700746 return NULL;
747}
748EXPORT_SYMBOL(find_vma);
749
750/*
David Howells930e6522006-09-27 01:50:22 -0700751 * find a VMA
752 * - we don't extend stack VMAs under NOMMU conditions
753 */
754struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
755{
756 return find_vma(mm, addr);
757}
758
David Howells8feae132009-01-08 12:04:47 +0000759/*
760 * expand a stack to a given address
761 * - not supported under NOMMU conditions
762 */
Greg Ungerer57c8f632007-07-15 23:38:28 -0700763int expand_stack(struct vm_area_struct *vma, unsigned long address)
764{
765 return -ENOMEM;
766}
767
David Howells930e6522006-09-27 01:50:22 -0700768/*
David Howells6fa5f802006-09-27 01:50:21 -0700769 * look up the first VMA exactly that exactly matches addr
770 * - should be called with mm->mmap_sem at least held readlocked
771 */
David Howells8feae132009-01-08 12:04:47 +0000772static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
773 unsigned long addr,
774 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775{
776 struct vm_area_struct *vma;
David Howells8feae132009-01-08 12:04:47 +0000777 struct rb_node *n = mm->mm_rb.rb_node;
778 unsigned long end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779
David Howells8feae132009-01-08 12:04:47 +0000780 /* check the cache first */
781 vma = mm->mmap_cache;
782 if (vma && vma->vm_start == addr && vma->vm_end == end)
783 return vma;
784
785 /* trawl the tree (there may be multiple mappings in which addr
786 * resides) */
787 for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 vma = rb_entry(n, struct vm_area_struct, vm_rb);
David Howells8feae132009-01-08 12:04:47 +0000789 if (vma->vm_start < addr)
790 continue;
791 if (vma->vm_start > addr)
792 return NULL;
793 if (vma->vm_end == end) {
794 mm->mmap_cache = vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 return vma;
David Howells8feae132009-01-08 12:04:47 +0000796 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797 }
798
799 return NULL;
800}
801
David Howells30340972006-09-27 01:50:20 -0700802/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 * determine whether a mapping should be permitted and, if so, what sort of
804 * mapping we're capable of supporting
805 */
806static int validate_mmap_request(struct file *file,
807 unsigned long addr,
808 unsigned long len,
809 unsigned long prot,
810 unsigned long flags,
811 unsigned long pgoff,
812 unsigned long *_capabilities)
813{
David Howells8feae132009-01-08 12:04:47 +0000814 unsigned long capabilities, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 unsigned long reqprot = prot;
816 int ret;
817
818 /* do the simple checks first */
819 if (flags & MAP_FIXED || addr) {
820 printk(KERN_DEBUG
821 "%d: Can't do fixed-address/overlay mmap of RAM\n",
822 current->pid);
823 return -EINVAL;
824 }
825
826 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
827 (flags & MAP_TYPE) != MAP_SHARED)
828 return -EINVAL;
829
Mike Frysingerf81cff0d2006-12-06 12:02:59 +1000830 if (!len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 return -EINVAL;
832
Mike Frysingerf81cff0d2006-12-06 12:02:59 +1000833 /* Careful about overflows.. */
David Howells8feae132009-01-08 12:04:47 +0000834 rlen = PAGE_ALIGN(len);
835 if (!rlen || rlen > TASK_SIZE)
Mike Frysingerf81cff0d2006-12-06 12:02:59 +1000836 return -ENOMEM;
837
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 /* offset overflow? */
David Howells8feae132009-01-08 12:04:47 +0000839 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
Mike Frysingerf81cff0d2006-12-06 12:02:59 +1000840 return -EOVERFLOW;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841
842 if (file) {
843 /* validate file mapping requests */
844 struct address_space *mapping;
845
846 /* files must support mmap */
847 if (!file->f_op || !file->f_op->mmap)
848 return -ENODEV;
849
850 /* work out if what we've got could possibly be shared
851 * - we support chardevs that provide their own "memory"
852 * - we support files/blockdevs that are memory backed
853 */
854 mapping = file->f_mapping;
855 if (!mapping)
Josef Sipeke9536ae2006-12-08 02:37:21 -0800856 mapping = file->f_path.dentry->d_inode->i_mapping;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857
858 capabilities = 0;
859 if (mapping && mapping->backing_dev_info)
860 capabilities = mapping->backing_dev_info->capabilities;
861
862 if (!capabilities) {
863 /* no explicit capabilities set, so assume some
864 * defaults */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800865 switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 case S_IFREG:
867 case S_IFBLK:
868 capabilities = BDI_CAP_MAP_COPY;
869 break;
870
871 case S_IFCHR:
872 capabilities =
873 BDI_CAP_MAP_DIRECT |
874 BDI_CAP_READ_MAP |
875 BDI_CAP_WRITE_MAP;
876 break;
877
878 default:
879 return -EINVAL;
880 }
881 }
882
883 /* eliminate any capabilities that we can't support on this
884 * device */
885 if (!file->f_op->get_unmapped_area)
886 capabilities &= ~BDI_CAP_MAP_DIRECT;
887 if (!file->f_op->read)
888 capabilities &= ~BDI_CAP_MAP_COPY;
889
890 if (flags & MAP_SHARED) {
891 /* do checks for writing, appending and locking */
892 if ((prot & PROT_WRITE) &&
893 !(file->f_mode & FMODE_WRITE))
894 return -EACCES;
895
Josef Sipeke9536ae2006-12-08 02:37:21 -0800896 if (IS_APPEND(file->f_path.dentry->d_inode) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 (file->f_mode & FMODE_WRITE))
898 return -EACCES;
899
Josef Sipeke9536ae2006-12-08 02:37:21 -0800900 if (locks_verify_locked(file->f_path.dentry->d_inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 return -EAGAIN;
902
903 if (!(capabilities & BDI_CAP_MAP_DIRECT))
904 return -ENODEV;
905
906 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
907 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
908 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
909 ) {
910 printk("MAP_SHARED not completely supported on !MMU\n");
911 return -EINVAL;
912 }
913
914 /* we mustn't privatise shared mappings */
915 capabilities &= ~BDI_CAP_MAP_COPY;
916 }
917 else {
918 /* we're going to read the file into private memory we
919 * allocate */
920 if (!(capabilities & BDI_CAP_MAP_COPY))
921 return -ENODEV;
922
923 /* we don't permit a private writable mapping to be
924 * shared with the backing device */
925 if (prot & PROT_WRITE)
926 capabilities &= ~BDI_CAP_MAP_DIRECT;
927 }
928
929 /* handle executable mappings and implied executable
930 * mappings */
Josef Sipeke9536ae2006-12-08 02:37:21 -0800931 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700932 if (prot & PROT_EXEC)
933 return -EPERM;
934 }
935 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
936 /* handle implication of PROT_EXEC by PROT_READ */
937 if (current->personality & READ_IMPLIES_EXEC) {
938 if (capabilities & BDI_CAP_EXEC_MAP)
939 prot |= PROT_EXEC;
940 }
941 }
942 else if ((prot & PROT_READ) &&
943 (prot & PROT_EXEC) &&
944 !(capabilities & BDI_CAP_EXEC_MAP)
945 ) {
946 /* backing file is not executable, try to copy */
947 capabilities &= ~BDI_CAP_MAP_DIRECT;
948 }
949 }
950 else {
951 /* anonymous mappings are always memory backed and can be
952 * privately mapped
953 */
954 capabilities = BDI_CAP_MAP_COPY;
955
956 /* handle PROT_EXEC implication by PROT_READ */
957 if ((prot & PROT_READ) &&
958 (current->personality & READ_IMPLIES_EXEC))
959 prot |= PROT_EXEC;
960 }
961
962 /* allow the security API to have its say */
Eric Parised032182007-06-28 15:55:21 -0400963 ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 if (ret < 0)
965 return ret;
966
967 /* looks okay */
968 *_capabilities = capabilities;
969 return 0;
970}
971
972/*
973 * we've determined that we can make the mapping, now translate what we
974 * now know into VMA flags
975 */
976static unsigned long determine_vm_flags(struct file *file,
977 unsigned long prot,
978 unsigned long flags,
979 unsigned long capabilities)
980{
981 unsigned long vm_flags;
982
983 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
984 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
985 /* vm_flags |= mm->def_flags; */
986
987 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
988 /* attempt to share read-only copies of mapped file chunks */
989 if (file && !(prot & PROT_WRITE))
990 vm_flags |= VM_MAYSHARE;
991 }
992 else {
993 /* overlay a shareable mapping on the backing device or inode
994 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
995 * romfs/cramfs */
996 if (flags & MAP_SHARED)
997 vm_flags |= VM_MAYSHARE | VM_SHARED;
998 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
999 vm_flags |= VM_MAYSHARE;
1000 }
1001
1002 /* refuse to let anyone share private mappings with this process if
1003 * it's being traced - otherwise breakpoints set in it may interfere
1004 * with another untraced process
1005 */
Roland McGrathfa8e26c2008-07-25 19:45:50 -07001006 if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 vm_flags &= ~VM_MAYSHARE;
1008
1009 return vm_flags;
1010}
1011
1012/*
David Howells8feae132009-01-08 12:04:47 +00001013 * set up a shared mapping on a file (the driver or filesystem provides and
1014 * pins the storage)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001015 */
David Howells8feae132009-01-08 12:04:47 +00001016static int do_mmap_shared_file(struct vm_area_struct *vma)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017{
1018 int ret;
1019
1020 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001021 if (ret == 0) {
1022 vma->vm_region->vm_top = vma->vm_region->vm_end;
1023 return ret;
1024 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 if (ret != -ENOSYS)
1026 return ret;
1027
1028 /* getting an ENOSYS error indicates that direct mmap isn't
1029 * possible (as opposed to tried but failed) so we'll fall
1030 * through to making a private copy of the data and mapping
1031 * that if we can */
1032 return -ENODEV;
1033}
1034
1035/*
1036 * set up a private mapping or an anonymous shared mapping
1037 */
David Howells8feae132009-01-08 12:04:47 +00001038static int do_mmap_private(struct vm_area_struct *vma,
1039 struct vm_region *region,
1040 unsigned long len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041{
David Howells8feae132009-01-08 12:04:47 +00001042 struct page *pages;
1043 unsigned long total, point, n, rlen;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044 void *base;
David Howells8feae132009-01-08 12:04:47 +00001045 int ret, order;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001046
1047 /* invoke the file's mapping function so that it can keep track of
1048 * shared mappings on devices or memory
1049 * - VM_MAYSHARE will be set if it may attempt to share
1050 */
1051 if (vma->vm_file) {
1052 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001053 if (ret == 0) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 /* shouldn't return success if we're not sharing */
Paul Mundtdd8632a2009-01-08 12:04:47 +00001055 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1056 vma->vm_region->vm_top = vma->vm_region->vm_end;
1057 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 }
Paul Mundtdd8632a2009-01-08 12:04:47 +00001059 if (ret != -ENOSYS)
1060 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001061
1062 /* getting an ENOSYS error indicates that direct mmap isn't
1063 * possible (as opposed to tried but failed) so we'll try to
1064 * make a private copy of the data and map that instead */
1065 }
1066
David Howells8feae132009-01-08 12:04:47 +00001067 rlen = PAGE_ALIGN(len);
1068
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 /* allocate some memory to hold the mapping
1070 * - note that this may not return a page-aligned address if the object
1071 * we're allocating is smaller than a page
1072 */
David Howells8feae132009-01-08 12:04:47 +00001073 order = get_order(rlen);
1074 kdebug("alloc order %d for %lx", order, len);
1075
1076 pages = alloc_pages(GFP_KERNEL, order);
1077 if (!pages)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 goto enomem;
1079
David Howells8feae132009-01-08 12:04:47 +00001080 total = 1 << order;
1081 atomic_add(total, &mmap_pages_allocated);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082
David Howells8feae132009-01-08 12:04:47 +00001083 point = rlen >> PAGE_SHIFT;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001084
1085 /* we allocated a power-of-2 sized page set, so we may want to trim off
1086 * the excess */
1087 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1088 while (total > point) {
1089 order = ilog2(total - point);
1090 n = 1 << order;
1091 kdebug("shave %lu/%lu @%lu", n, total - point, total);
1092 atomic_sub(n, &mmap_pages_allocated);
1093 total -= n;
1094 set_page_refcounted(pages + total);
1095 __free_pages(pages + total, order);
1096 }
David Howells8feae132009-01-08 12:04:47 +00001097 }
1098
David Howells8feae132009-01-08 12:04:47 +00001099 for (point = 1; point < total; point++)
1100 set_page_refcounted(&pages[point]);
1101
1102 base = page_address(pages);
1103 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1104 region->vm_start = (unsigned long) base;
1105 region->vm_end = region->vm_start + rlen;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001106 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
David Howells8feae132009-01-08 12:04:47 +00001107
1108 vma->vm_start = region->vm_start;
1109 vma->vm_end = region->vm_start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110
1111 if (vma->vm_file) {
1112 /* read the contents of a file into the copy */
1113 mm_segment_t old_fs;
1114 loff_t fpos;
1115
1116 fpos = vma->vm_pgoff;
1117 fpos <<= PAGE_SHIFT;
1118
1119 old_fs = get_fs();
1120 set_fs(KERNEL_DS);
David Howells8feae132009-01-08 12:04:47 +00001121 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001122 set_fs(old_fs);
1123
1124 if (ret < 0)
1125 goto error_free;
1126
1127 /* clear the last little bit */
David Howells8feae132009-01-08 12:04:47 +00001128 if (ret < rlen)
1129 memset(base + ret, 0, rlen - ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001130
1131 } else {
1132 /* if it's an anonymous mapping, then just clear it */
David Howells8feae132009-01-08 12:04:47 +00001133 memset(base, 0, rlen);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 }
1135
1136 return 0;
1137
1138error_free:
David Howells8feae132009-01-08 12:04:47 +00001139 free_page_series(region->vm_start, region->vm_end);
1140 region->vm_start = vma->vm_start = 0;
1141 region->vm_end = vma->vm_end = 0;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001142 region->vm_top = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 return ret;
1144
1145enomem:
1146 printk("Allocation of length %lu from process %d failed\n",
1147 len, current->pid);
1148 show_free_areas();
1149 return -ENOMEM;
1150}
1151
1152/*
1153 * handle mapping creation for uClinux
1154 */
1155unsigned long do_mmap_pgoff(struct file *file,
1156 unsigned long addr,
1157 unsigned long len,
1158 unsigned long prot,
1159 unsigned long flags,
1160 unsigned long pgoff)
1161{
David Howells8feae132009-01-08 12:04:47 +00001162 struct vm_area_struct *vma;
1163 struct vm_region *region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 struct rb_node *rb;
David Howells8feae132009-01-08 12:04:47 +00001165 unsigned long capabilities, vm_flags, result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166 int ret;
1167
David Howells8feae132009-01-08 12:04:47 +00001168 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1169
Eric Paris7cd94142007-11-26 18:47:40 -05001170 if (!(flags & MAP_FIXED))
1171 addr = round_hint_to_min(addr);
1172
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 /* decide whether we should attempt the mapping, and if so what sort of
1174 * mapping */
1175 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1176 &capabilities);
David Howells8feae132009-01-08 12:04:47 +00001177 if (ret < 0) {
1178 kleave(" = %d [val]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001179 return ret;
David Howells8feae132009-01-08 12:04:47 +00001180 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001181
1182 /* we've determined that we can make the mapping, now translate what we
1183 * now know into VMA flags */
1184 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1185
David Howells8feae132009-01-08 12:04:47 +00001186 /* we're going to need to record the mapping */
1187 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1188 if (!region)
1189 goto error_getting_region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
David Howells8feae132009-01-08 12:04:47 +00001191 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1192 if (!vma)
1193 goto error_getting_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194
David Howells8feae132009-01-08 12:04:47 +00001195 atomic_set(&region->vm_usage, 1);
1196 region->vm_flags = vm_flags;
1197 region->vm_pgoff = pgoff;
1198
1199 INIT_LIST_HEAD(&vma->anon_vma_node);
1200 vma->vm_flags = vm_flags;
1201 vma->vm_pgoff = pgoff;
1202
1203 if (file) {
1204 region->vm_file = file;
1205 get_file(file);
1206 vma->vm_file = file;
1207 get_file(file);
1208 if (vm_flags & VM_EXECUTABLE) {
1209 added_exe_file_vma(current->mm);
1210 vma->vm_mm = current->mm;
1211 }
1212 }
1213
1214 down_write(&nommu_region_sem);
1215
1216 /* if we want to share, we need to check for regions created by other
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 * mmap() calls that overlap with our proposed mapping
David Howells8feae132009-01-08 12:04:47 +00001218 * - we can only share with a superset match on most regular files
Linus Torvalds1da177e2005-04-16 15:20:36 -07001219 * - shared mappings on character devices and memory backed files are
1220 * permitted to overlap inexactly as far as we are concerned for in
1221 * these cases, sharing is handled in the driver or filesystem rather
1222 * than here
1223 */
1224 if (vm_flags & VM_MAYSHARE) {
David Howells8feae132009-01-08 12:04:47 +00001225 struct vm_region *pregion;
1226 unsigned long pglen, rpglen, pgend, rpgend, start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001227
David Howells8feae132009-01-08 12:04:47 +00001228 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1229 pgend = pgoff + pglen;
David Howells165b2392007-03-22 00:11:24 -08001230
David Howells8feae132009-01-08 12:04:47 +00001231 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1232 pregion = rb_entry(rb, struct vm_region, vm_rb);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001233
David Howells8feae132009-01-08 12:04:47 +00001234 if (!(pregion->vm_flags & VM_MAYSHARE))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235 continue;
1236
1237 /* search for overlapping mappings on the same file */
David Howells8feae132009-01-08 12:04:47 +00001238 if (pregion->vm_file->f_path.dentry->d_inode !=
1239 file->f_path.dentry->d_inode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 continue;
1241
David Howells8feae132009-01-08 12:04:47 +00001242 if (pregion->vm_pgoff >= pgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001243 continue;
1244
David Howells8feae132009-01-08 12:04:47 +00001245 rpglen = pregion->vm_end - pregion->vm_start;
1246 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1247 rpgend = pregion->vm_pgoff + rpglen;
1248 if (pgoff >= rpgend)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 continue;
1250
David Howells8feae132009-01-08 12:04:47 +00001251 /* handle inexactly overlapping matches between
1252 * mappings */
1253 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1254 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1255 /* new mapping is not a subset of the region */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1257 goto sharing_violation;
1258 continue;
1259 }
1260
David Howells8feae132009-01-08 12:04:47 +00001261 /* we've found a region we can share */
1262 atomic_inc(&pregion->vm_usage);
1263 vma->vm_region = pregion;
1264 start = pregion->vm_start;
1265 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1266 vma->vm_start = start;
1267 vma->vm_end = start + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268
David Howells8feae132009-01-08 12:04:47 +00001269 if (pregion->vm_flags & VM_MAPPED_COPY) {
1270 kdebug("share copy");
1271 vma->vm_flags |= VM_MAPPED_COPY;
1272 } else {
1273 kdebug("share mmap");
1274 ret = do_mmap_shared_file(vma);
1275 if (ret < 0) {
1276 vma->vm_region = NULL;
1277 vma->vm_start = 0;
1278 vma->vm_end = 0;
1279 atomic_dec(&pregion->vm_usage);
1280 pregion = NULL;
1281 goto error_just_free;
1282 }
1283 }
1284 fput(region->vm_file);
1285 kmem_cache_free(vm_region_jar, region);
1286 region = pregion;
1287 result = start;
1288 goto share;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001289 }
1290
Linus Torvalds1da177e2005-04-16 15:20:36 -07001291 /* obtain the address at which to make a shared mapping
1292 * - this is the hook for quasi-memory character devices to
1293 * tell us the location of a shared mapping
1294 */
1295 if (file && file->f_op->get_unmapped_area) {
1296 addr = file->f_op->get_unmapped_area(file, addr, len,
1297 pgoff, flags);
1298 if (IS_ERR((void *) addr)) {
1299 ret = addr;
1300 if (ret != (unsigned long) -ENOSYS)
David Howells8feae132009-01-08 12:04:47 +00001301 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001302
1303 /* the driver refused to tell us where to site
1304 * the mapping so we'll have to attempt to copy
1305 * it */
1306 ret = (unsigned long) -ENODEV;
1307 if (!(capabilities & BDI_CAP_MAP_COPY))
David Howells8feae132009-01-08 12:04:47 +00001308 goto error_just_free;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309
1310 capabilities &= ~BDI_CAP_MAP_DIRECT;
David Howells8feae132009-01-08 12:04:47 +00001311 } else {
1312 vma->vm_start = region->vm_start = addr;
1313 vma->vm_end = region->vm_end = addr + len;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314 }
1315 }
1316 }
1317
David Howells8feae132009-01-08 12:04:47 +00001318 vma->vm_region = region;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
1320 /* set up the mapping */
1321 if (file && vma->vm_flags & VM_SHARED)
David Howells8feae132009-01-08 12:04:47 +00001322 ret = do_mmap_shared_file(vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001323 else
David Howells8feae132009-01-08 12:04:47 +00001324 ret = do_mmap_private(vma, region, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 if (ret < 0)
David Howells8feae132009-01-08 12:04:47 +00001326 goto error_put_region;
1327
1328 add_nommu_region(region);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001329
1330 /* okay... we have a mapping; now we have to register it */
David Howells8feae132009-01-08 12:04:47 +00001331 result = vma->vm_start;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332
Linus Torvalds1da177e2005-04-16 15:20:36 -07001333 current->mm->total_vm += len >> PAGE_SHIFT;
1334
David Howells8feae132009-01-08 12:04:47 +00001335share:
1336 add_vma_to_mm(current->mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337
David Howells8feae132009-01-08 12:04:47 +00001338 up_write(&nommu_region_sem);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339
1340 if (prot & PROT_EXEC)
David Howells8feae132009-01-08 12:04:47 +00001341 flush_icache_range(result, result + len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001342
David Howells8feae132009-01-08 12:04:47 +00001343 kleave(" = %lx", result);
1344 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
David Howells8feae132009-01-08 12:04:47 +00001346error_put_region:
1347 __put_nommu_region(region);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 if (vma) {
Matt Helsley925d1c42008-04-29 01:01:36 -07001349 if (vma->vm_file) {
Gavin Lambert3fcd03e2006-09-30 23:27:01 -07001350 fput(vma->vm_file);
Matt Helsley925d1c42008-04-29 01:01:36 -07001351 if (vma->vm_flags & VM_EXECUTABLE)
1352 removed_exe_file_vma(vma->vm_mm);
1353 }
David Howells8feae132009-01-08 12:04:47 +00001354 kmem_cache_free(vm_area_cachep, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 }
David Howells8feae132009-01-08 12:04:47 +00001356 kleave(" = %d [pr]", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 return ret;
1358
David Howells8feae132009-01-08 12:04:47 +00001359error_just_free:
1360 up_write(&nommu_region_sem);
1361error:
1362 fput(region->vm_file);
1363 kmem_cache_free(vm_region_jar, region);
1364 fput(vma->vm_file);
1365 if (vma->vm_flags & VM_EXECUTABLE)
1366 removed_exe_file_vma(vma->vm_mm);
1367 kmem_cache_free(vm_area_cachep, vma);
1368 kleave(" = %d", ret);
1369 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370
David Howells8feae132009-01-08 12:04:47 +00001371sharing_violation:
1372 up_write(&nommu_region_sem);
1373 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1374 ret = -EINVAL;
1375 goto error;
1376
1377error_getting_vma:
1378 kmem_cache_free(vm_region_jar, region);
1379 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1380 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 len, current->pid);
1382 show_free_areas();
1383 return -ENOMEM;
1384
David Howells8feae132009-01-08 12:04:47 +00001385error_getting_region:
1386 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1387 " from process %d failed\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 len, current->pid);
1389 show_free_areas();
1390 return -ENOMEM;
1391}
Paul Mundtb5073172007-07-21 04:37:25 -07001392EXPORT_SYMBOL(do_mmap_pgoff);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393
1394/*
David Howells8feae132009-01-08 12:04:47 +00001395 * split a vma into two pieces at address 'addr', a new vma is allocated either
1396 * for the first part or the tail.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 */
David Howells8feae132009-01-08 12:04:47 +00001398int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1399 unsigned long addr, int new_below)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001400{
David Howells8feae132009-01-08 12:04:47 +00001401 struct vm_area_struct *new;
1402 struct vm_region *region;
1403 unsigned long npages;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404
David Howells8feae132009-01-08 12:04:47 +00001405 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001406
David Howells8feae132009-01-08 12:04:47 +00001407 /* we're only permitted to split anonymous regions that have a single
1408 * owner */
1409 if (vma->vm_file ||
1410 atomic_read(&vma->vm_region->vm_usage) != 1)
1411 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412
David Howells8feae132009-01-08 12:04:47 +00001413 if (mm->map_count >= sysctl_max_map_count)
1414 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
David Howells8feae132009-01-08 12:04:47 +00001416 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1417 if (!region)
1418 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419
David Howells8feae132009-01-08 12:04:47 +00001420 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1421 if (!new) {
1422 kmem_cache_free(vm_region_jar, region);
1423 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 }
David Howells8feae132009-01-08 12:04:47 +00001425
1426 /* most fields are the same, copy all, and then fixup */
1427 *new = *vma;
1428 *region = *vma->vm_region;
1429 new->vm_region = region;
1430
1431 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1432
1433 if (new_below) {
Paul Mundtdd8632a2009-01-08 12:04:47 +00001434 region->vm_top = region->vm_end = new->vm_end = addr;
David Howells8feae132009-01-08 12:04:47 +00001435 } else {
1436 region->vm_start = new->vm_start = addr;
1437 region->vm_pgoff = new->vm_pgoff += npages;
1438 }
1439
1440 if (new->vm_ops && new->vm_ops->open)
1441 new->vm_ops->open(new);
1442
1443 delete_vma_from_mm(vma);
1444 down_write(&nommu_region_sem);
1445 delete_nommu_region(vma->vm_region);
1446 if (new_below) {
1447 vma->vm_region->vm_start = vma->vm_start = addr;
1448 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1449 } else {
1450 vma->vm_region->vm_end = vma->vm_end = addr;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001451 vma->vm_region->vm_top = addr;
David Howells8feae132009-01-08 12:04:47 +00001452 }
1453 add_nommu_region(vma->vm_region);
1454 add_nommu_region(new->vm_region);
1455 up_write(&nommu_region_sem);
1456 add_vma_to_mm(mm, vma);
1457 add_vma_to_mm(mm, new);
1458 return 0;
1459}
1460
1461/*
1462 * shrink a VMA by removing the specified chunk from either the beginning or
1463 * the end
1464 */
1465static int shrink_vma(struct mm_struct *mm,
1466 struct vm_area_struct *vma,
1467 unsigned long from, unsigned long to)
1468{
1469 struct vm_region *region;
1470
1471 kenter("");
1472
1473 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1474 * and list */
1475 delete_vma_from_mm(vma);
1476 if (from > vma->vm_start)
1477 vma->vm_end = from;
1478 else
1479 vma->vm_start = to;
1480 add_vma_to_mm(mm, vma);
1481
1482 /* cut the backing region down to size */
1483 region = vma->vm_region;
1484 BUG_ON(atomic_read(&region->vm_usage) != 1);
1485
1486 down_write(&nommu_region_sem);
1487 delete_nommu_region(region);
Paul Mundtdd8632a2009-01-08 12:04:47 +00001488 if (from > region->vm_start) {
1489 to = region->vm_top;
1490 region->vm_top = region->vm_end = from;
1491 } else {
David Howells8feae132009-01-08 12:04:47 +00001492 region->vm_start = to;
Paul Mundtdd8632a2009-01-08 12:04:47 +00001493 }
David Howells8feae132009-01-08 12:04:47 +00001494 add_nommu_region(region);
1495 up_write(&nommu_region_sem);
1496
1497 free_page_series(from, to);
1498 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001499}
1500
David Howells30340972006-09-27 01:50:20 -07001501/*
1502 * release a mapping
David Howells8feae132009-01-08 12:04:47 +00001503 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1504 * VMA, though it need not cover the whole VMA
David Howells30340972006-09-27 01:50:20 -07001505 */
David Howells8feae132009-01-08 12:04:47 +00001506int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001507{
David Howells8feae132009-01-08 12:04:47 +00001508 struct vm_area_struct *vma;
1509 struct rb_node *rb;
1510 unsigned long end = start + len;
1511 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512
David Howells8feae132009-01-08 12:04:47 +00001513 kenter(",%lx,%zx", start, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514
David Howells8feae132009-01-08 12:04:47 +00001515 if (len == 0)
1516 return -EINVAL;
1517
1518 /* find the first potentially overlapping VMA */
1519 vma = find_vma(mm, start);
1520 if (!vma) {
1521 printk(KERN_WARNING
1522 "munmap of memory not mmapped by process %d (%s):"
1523 " 0x%lx-0x%lx\n",
1524 current->pid, current->comm, start, start + len - 1);
1525 return -EINVAL;
David Howells30340972006-09-27 01:50:20 -07001526 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527
David Howells8feae132009-01-08 12:04:47 +00001528 /* we're allowed to split an anonymous VMA but not a file-backed one */
1529 if (vma->vm_file) {
1530 do {
1531 if (start > vma->vm_start) {
1532 kleave(" = -EINVAL [miss]");
1533 return -EINVAL;
1534 }
1535 if (end == vma->vm_end)
1536 goto erase_whole_vma;
1537 rb = rb_next(&vma->vm_rb);
1538 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1539 } while (rb);
1540 kleave(" = -EINVAL [split file]");
1541 return -EINVAL;
1542 } else {
1543 /* the chunk must be a subset of the VMA found */
1544 if (start == vma->vm_start && end == vma->vm_end)
1545 goto erase_whole_vma;
1546 if (start < vma->vm_start || end > vma->vm_end) {
1547 kleave(" = -EINVAL [superset]");
1548 return -EINVAL;
1549 }
1550 if (start & ~PAGE_MASK) {
1551 kleave(" = -EINVAL [unaligned start]");
1552 return -EINVAL;
1553 }
1554 if (end != vma->vm_end && end & ~PAGE_MASK) {
1555 kleave(" = -EINVAL [unaligned split]");
1556 return -EINVAL;
1557 }
1558 if (start != vma->vm_start && end != vma->vm_end) {
1559 ret = split_vma(mm, vma, start, 1);
1560 if (ret < 0) {
1561 kleave(" = %d [split]", ret);
1562 return ret;
1563 }
1564 }
1565 return shrink_vma(mm, vma, start, end);
1566 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001567
David Howells8feae132009-01-08 12:04:47 +00001568erase_whole_vma:
1569 delete_vma_from_mm(vma);
1570 delete_vma(mm, vma);
1571 kleave(" = 0");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572 return 0;
1573}
Paul Mundtb5073172007-07-21 04:37:25 -07001574EXPORT_SYMBOL(do_munmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001575
David Howells30340972006-09-27 01:50:20 -07001576asmlinkage long sys_munmap(unsigned long addr, size_t len)
1577{
1578 int ret;
1579 struct mm_struct *mm = current->mm;
1580
1581 down_write(&mm->mmap_sem);
1582 ret = do_munmap(mm, addr, len);
1583 up_write(&mm->mmap_sem);
1584 return ret;
1585}
1586
1587/*
David Howells8feae132009-01-08 12:04:47 +00001588 * release all the mappings made in a process's VM space
David Howells30340972006-09-27 01:50:20 -07001589 */
David Howells8feae132009-01-08 12:04:47 +00001590void exit_mmap(struct mm_struct *mm)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001591{
David Howells8feae132009-01-08 12:04:47 +00001592 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001593
David Howells8feae132009-01-08 12:04:47 +00001594 if (!mm)
1595 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596
David Howells8feae132009-01-08 12:04:47 +00001597 kenter("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001598
David Howells8feae132009-01-08 12:04:47 +00001599 mm->total_vm = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001600
David Howells8feae132009-01-08 12:04:47 +00001601 while ((vma = mm->mmap)) {
1602 mm->mmap = vma->vm_next;
1603 delete_vma_from_mm(vma);
1604 delete_vma(mm, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605 }
David Howells8feae132009-01-08 12:04:47 +00001606
1607 kleave("");
Linus Torvalds1da177e2005-04-16 15:20:36 -07001608}
1609
Linus Torvalds1da177e2005-04-16 15:20:36 -07001610unsigned long do_brk(unsigned long addr, unsigned long len)
1611{
1612 return -ENOMEM;
1613}
1614
1615/*
David Howells6fa5f802006-09-27 01:50:21 -07001616 * expand (or shrink) an existing mapping, potentially moving it at the same
1617 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001618 *
David Howells6fa5f802006-09-27 01:50:21 -07001619 * under NOMMU conditions, we only permit changing a mapping's size, and only
David Howells8feae132009-01-08 12:04:47 +00001620 * as long as it stays within the region allocated by do_mmap_private() and the
1621 * block is not shareable
Linus Torvalds1da177e2005-04-16 15:20:36 -07001622 *
David Howells6fa5f802006-09-27 01:50:21 -07001623 * MREMAP_FIXED is not supported under NOMMU conditions
Linus Torvalds1da177e2005-04-16 15:20:36 -07001624 */
1625unsigned long do_mremap(unsigned long addr,
1626 unsigned long old_len, unsigned long new_len,
1627 unsigned long flags, unsigned long new_addr)
1628{
David Howells6fa5f802006-09-27 01:50:21 -07001629 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001630
1631 /* insanity checks first */
David Howells8feae132009-01-08 12:04:47 +00001632 if (old_len == 0 || new_len == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633 return (unsigned long) -EINVAL;
1634
David Howells8feae132009-01-08 12:04:47 +00001635 if (addr & ~PAGE_MASK)
1636 return -EINVAL;
1637
Linus Torvalds1da177e2005-04-16 15:20:36 -07001638 if (flags & MREMAP_FIXED && new_addr != addr)
1639 return (unsigned long) -EINVAL;
1640
David Howells8feae132009-01-08 12:04:47 +00001641 vma = find_vma_exact(current->mm, addr, old_len);
David Howells6fa5f802006-09-27 01:50:21 -07001642 if (!vma)
1643 return (unsigned long) -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644
David Howells6fa5f802006-09-27 01:50:21 -07001645 if (vma->vm_end != vma->vm_start + old_len)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001646 return (unsigned long) -EFAULT;
1647
David Howells6fa5f802006-09-27 01:50:21 -07001648 if (vma->vm_flags & VM_MAYSHARE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649 return (unsigned long) -EPERM;
1650
David Howells8feae132009-01-08 12:04:47 +00001651 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001652 return (unsigned long) -ENOMEM;
1653
1654 /* all checks complete - do it */
David Howells6fa5f802006-09-27 01:50:21 -07001655 vma->vm_end = vma->vm_start + new_len;
David Howells6fa5f802006-09-27 01:50:21 -07001656 return vma->vm_start;
1657}
Paul Mundtb5073172007-07-21 04:37:25 -07001658EXPORT_SYMBOL(do_mremap);
David Howells6fa5f802006-09-27 01:50:21 -07001659
David Howells8feae132009-01-08 12:04:47 +00001660asmlinkage
1661unsigned long sys_mremap(unsigned long addr,
1662 unsigned long old_len, unsigned long new_len,
1663 unsigned long flags, unsigned long new_addr)
David Howells6fa5f802006-09-27 01:50:21 -07001664{
1665 unsigned long ret;
1666
1667 down_write(&current->mm->mmap_sem);
1668 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1669 up_write(&current->mm->mmap_sem);
1670 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001671}
1672
Linus Torvalds6aab3412005-11-28 14:34:23 -08001673struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001674 unsigned int foll_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001675{
1676 return NULL;
1677}
1678
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1680 unsigned long to, unsigned long size, pgprot_t prot)
1681{
Greg Ungerer66aa2b42005-09-12 11:18:10 +10001682 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1683 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001684}
Luke Yang22c4af42006-07-14 00:24:09 -07001685EXPORT_SYMBOL(remap_pfn_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001686
Paul Mundtf905bc42008-02-04 22:29:59 -08001687int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1688 unsigned long pgoff)
1689{
1690 unsigned int size = vma->vm_end - vma->vm_start;
1691
1692 if (!(vma->vm_flags & VM_USERMAP))
1693 return -EINVAL;
1694
1695 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1696 vma->vm_end = vma->vm_start + size;
1697
1698 return 0;
1699}
1700EXPORT_SYMBOL(remap_vmalloc_range);
1701
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1703{
1704}
1705
1706unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1707 unsigned long len, unsigned long pgoff, unsigned long flags)
1708{
1709 return -ENOMEM;
1710}
1711
Wolfgang Wander1363c3c2005-06-21 17:14:49 -07001712void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001713{
1714}
1715
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716void unmap_mapping_range(struct address_space *mapping,
1717 loff_t const holebegin, loff_t const holelen,
1718 int even_cows)
1719{
1720}
Luke Yang22c4af42006-07-14 00:24:09 -07001721EXPORT_SYMBOL(unmap_mapping_range);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722
1723/*
David Howellsd56e03c2007-03-22 00:11:23 -08001724 * ask for an unmapped area at which to create a mapping on a file
1725 */
1726unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1727 unsigned long len, unsigned long pgoff,
1728 unsigned long flags)
1729{
1730 unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1731 unsigned long, unsigned long);
1732
1733 get_area = current->mm->get_unmapped_area;
1734 if (file && file->f_op && file->f_op->get_unmapped_area)
1735 get_area = file->f_op->get_unmapped_area;
1736
1737 if (!get_area)
1738 return -ENOSYS;
1739
1740 return get_area(file, addr, len, pgoff, flags);
1741}
David Howellsd56e03c2007-03-22 00:11:23 -08001742EXPORT_SYMBOL(get_unmapped_area);
1743
1744/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745 * Check that a process has enough memory to allocate a new virtual
1746 * mapping. 0 means there is enough memory for the allocation to
1747 * succeed and -ENOMEM implies there is not.
1748 *
1749 * We currently support three overcommit policies, which are set via the
1750 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1751 *
1752 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1753 * Additional code 2002 Jul 20 by Robert Love.
1754 *
1755 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1756 *
1757 * Note this is a helper function intended to be used by LSMs which
1758 * wish to use this logic.
1759 */
Alan Cox34b4e4a2007-08-22 14:01:28 -07001760int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761{
1762 unsigned long free, allowed;
1763
1764 vm_acct_memory(pages);
1765
1766 /*
1767 * Sometimes we want to use more memory than we have
1768 */
1769 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1770 return 0;
1771
1772 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1773 unsigned long n;
1774
Christoph Lameter347ce432006-06-30 01:55:35 -07001775 free = global_page_state(NR_FILE_PAGES);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776 free += nr_swap_pages;
1777
1778 /*
1779 * Any slabs which are created with the
1780 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1781 * which are reclaimable, under pressure. The dentry
1782 * cache and most inode caches should fall into this
1783 */
Christoph Lameter972d1a72006-09-25 23:31:51 -07001784 free += global_page_state(NR_SLAB_RECLAIMABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785
1786 /*
1787 * Leave the last 3% for root
1788 */
1789 if (!cap_sys_admin)
1790 free -= free / 32;
1791
1792 if (free > pages)
1793 return 0;
1794
1795 /*
1796 * nr_free_pages() is very expensive on large systems,
1797 * only call if we're about to fail.
1798 */
1799 n = nr_free_pages();
Hideo AOKId5ddc792006-04-10 22:53:01 -07001800
1801 /*
1802 * Leave reserved pages. The pages are not for anonymous pages.
1803 */
1804 if (n <= totalreserve_pages)
1805 goto error;
1806 else
1807 n -= totalreserve_pages;
1808
1809 /*
1810 * Leave the last 3% for root
1811 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001812 if (!cap_sys_admin)
1813 n -= n / 32;
1814 free += n;
1815
1816 if (free > pages)
1817 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001818
1819 goto error;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 }
1821
1822 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1823 /*
1824 * Leave the last 3% for root
1825 */
1826 if (!cap_sys_admin)
1827 allowed -= allowed / 32;
1828 allowed += total_swap_pages;
1829
1830 /* Don't let a single process grow too big:
1831 leave 3% of the size of this process for other processes */
Alan Cox731572d2008-10-29 14:01:20 -07001832 if (mm)
1833 allowed -= mm->total_vm / 32;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834
Simon Derr2f60f8d2005-08-04 19:52:03 -07001835 /*
1836 * cast `allowed' as a signed long because vm_committed_space
1837 * sometimes has a negative value
1838 */
Alan Cox80119ef2008-05-23 13:04:31 -07001839 if (atomic_long_read(&vm_committed_space) < (long)allowed)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840 return 0;
Hideo AOKId5ddc792006-04-10 22:53:01 -07001841error:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842 vm_unacct_memory(pages);
1843
1844 return -ENOMEM;
1845}
1846
1847int in_gate_area_no_task(unsigned long addr)
1848{
1849 return 0;
1850}
David Howellsb0e15192006-01-06 00:11:42 -08001851
Nick Piggind0217ac2007-07-19 01:47:03 -07001852int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
David Howellsb0e15192006-01-06 00:11:42 -08001853{
1854 BUG();
Nick Piggind0217ac2007-07-19 01:47:03 -07001855 return 0;
David Howellsb0e15192006-01-06 00:11:42 -08001856}
Paul Mundtb5073172007-07-21 04:37:25 -07001857EXPORT_SYMBOL(filemap_fault);
David Howells0ec76a12006-09-27 01:50:15 -07001858
1859/*
1860 * Access another process' address space.
1861 * - source/target buffer must be kernel space
1862 */
1863int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1864{
David Howells0ec76a12006-09-27 01:50:15 -07001865 struct vm_area_struct *vma;
1866 struct mm_struct *mm;
1867
1868 if (addr + len < addr)
1869 return 0;
1870
1871 mm = get_task_mm(tsk);
1872 if (!mm)
1873 return 0;
1874
1875 down_read(&mm->mmap_sem);
1876
1877 /* the access must start within one of the target process's mappings */
David Howells0159b142006-09-27 01:50:16 -07001878 vma = find_vma(mm, addr);
1879 if (vma) {
David Howells0ec76a12006-09-27 01:50:15 -07001880 /* don't overrun this mapping */
1881 if (addr + len >= vma->vm_end)
1882 len = vma->vm_end - addr;
1883
1884 /* only read or write mappings where it is permitted */
David Howellsd00c7b992006-09-27 01:50:19 -07001885 if (write && vma->vm_flags & VM_MAYWRITE)
David Howells0ec76a12006-09-27 01:50:15 -07001886 len -= copy_to_user((void *) addr, buf, len);
David Howellsd00c7b992006-09-27 01:50:19 -07001887 else if (!write && vma->vm_flags & VM_MAYREAD)
David Howells0ec76a12006-09-27 01:50:15 -07001888 len -= copy_from_user(buf, (void *) addr, len);
1889 else
1890 len = 0;
1891 } else {
1892 len = 0;
1893 }
1894
1895 up_read(&mm->mmap_sem);
1896 mmput(mm);
1897 return len;
1898}