nommu: fix two build breakages
[linux-2.6.git] / mm / nommu.c
1 /*
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  *
9  *  Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
10  *  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>
13  *  Copyright (c) 2007-2009 Paul Mundt <lethal@linux-sh.org>
14  */
15
16 #include <linux/module.h>
17 #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>
25 #include <linux/tracehook.h>
26 #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>
36 #include <asm/mmu_context.h>
37 #include "internal.h"
38
39 static inline __attribute__((format(printf, 1, 2)))
40 void no_printk(const char *fmt, ...)
41 {
42 }
43
44 #if 0
45 #define kenter(FMT, ...) \
46         printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
47 #define kleave(FMT, ...) \
48         printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
49 #define kdebug(FMT, ...) \
50         printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
51 #else
52 #define kenter(FMT, ...) \
53         no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
54 #define kleave(FMT, ...) \
55         no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
56 #define kdebug(FMT, ...) \
57         no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
58 #endif
59
60 void *high_memory;
61 struct page *mem_map;
62 unsigned long max_mapnr;
63 unsigned long num_physpages;
64 unsigned long highest_memmap_pfn;
65 struct percpu_counter vm_committed_as;
66 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
67 int sysctl_overcommit_ratio = 50; /* default is 50% */
68 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
69 int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
70 int heap_stack_gap = 0;
71
72 atomic_long_t mmap_pages_allocated;
73
74 EXPORT_SYMBOL(mem_map);
75 EXPORT_SYMBOL(num_physpages);
76
77 /* list of mapped, potentially shareable regions */
78 static struct kmem_cache *vm_region_jar;
79 struct rb_root nommu_region_tree = RB_ROOT;
80 DECLARE_RWSEM(nommu_region_sem);
81
82 struct 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  */
93 int 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
105 do_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
113 out_truncate:
114         if (inode->i_op->truncate)
115                 inode->i_op->truncate(inode);
116         return 0;
117 out_sig:
118         send_sig(SIGXFSZ, current, 0);
119 out:
120         return -EFBIG;
121 }
122
123 EXPORT_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  */
131 unsigned int kobjsize(const void *objp)
132 {
133         struct page *page;
134
135         /*
136          * If the object we have should not have ksize performed on it,
137          * return size of 0
138          */
139         if (!objp || !virt_addr_valid(objp))
140                 return 0;
141
142         page = virt_to_head_page(objp);
143
144         /*
145          * If the allocator sets PageSlab, we know the pointer came from
146          * kmalloc().
147          */
148         if (PageSlab(page))
149                 return ksize(objp);
150
151         /*
152          * 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         /*
166          * The ksize() function is only guaranteed to work for pointers
167          * returned by kmalloc(). So handle arbitrary pointers here.
168          */
169         return PAGE_SIZE << compound_order(page);
170 }
171
172 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
173                      unsigned long start, int nr_pages, unsigned int foll_flags,
174                      struct page **pages, struct vm_area_struct **vmas)
175 {
176         struct vm_area_struct *vma;
177         unsigned long vm_flags;
178         int i;
179
180         /* calculate required read or write permissions.
181          * If FOLL_FORCE is set, we only require the "MAY" flags.
182          */
183         vm_flags  = (foll_flags & FOLL_WRITE) ?
184                         (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
185         vm_flags &= (foll_flags & FOLL_FORCE) ?
186                         (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
187
188         for (i = 0; i < nr_pages; i++) {
189                 vma = find_vma(mm, start);
190                 if (!vma)
191                         goto finish_or_fault;
192
193                 /* protect what we can, including chardevs */
194                 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
195                     !(vm_flags & vma->vm_flags))
196                         goto finish_or_fault;
197
198                 if (pages) {
199                         pages[i] = virt_to_page(start);
200                         if (pages[i])
201                                 page_cache_get(pages[i]);
202                 }
203                 if (vmas)
204                         vmas[i] = vma;
205                 start += PAGE_SIZE;
206         }
207
208         return i;
209
210 finish_or_fault:
211         return i ? : -EFAULT;
212 }
213
214 /*
215  * get a list of pages in an address range belonging to the specified process
216  * and indicate the VMA that covers each page
217  * - this is potentially dodgy as we may end incrementing the page count of a
218  *   slab page or a secondary page from a compound page
219  * - don't permit access to VMAs that don't support it, such as I/O mappings
220  */
221 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
222         unsigned long start, int nr_pages, int write, int force,
223         struct page **pages, struct vm_area_struct **vmas)
224 {
225         int flags = 0;
226
227         if (write)
228                 flags |= FOLL_WRITE;
229         if (force)
230                 flags |= FOLL_FORCE;
231
232         return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
233 }
234 EXPORT_SYMBOL(get_user_pages);
235
236 /**
237  * follow_pfn - look up PFN at a user virtual address
238  * @vma: memory mapping
239  * @address: user virtual address
240  * @pfn: location to store found PFN
241  *
242  * Only IO mappings and raw PFN mappings are allowed.
243  *
244  * Returns zero and the pfn at @pfn on success, -ve otherwise.
245  */
246 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
247         unsigned long *pfn)
248 {
249         if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
250                 return -EINVAL;
251
252         *pfn = address >> PAGE_SHIFT;
253         return 0;
254 }
255 EXPORT_SYMBOL(follow_pfn);
256
257 DEFINE_RWLOCK(vmlist_lock);
258 struct vm_struct *vmlist;
259
260 void vfree(const void *addr)
261 {
262         kfree(addr);
263 }
264 EXPORT_SYMBOL(vfree);
265
266 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
267 {
268         /*
269          *  You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
270          * returns only a logical address.
271          */
272         return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
273 }
274 EXPORT_SYMBOL(__vmalloc);
275
276 void *vmalloc_user(unsigned long size)
277 {
278         void *ret;
279
280         ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
281                         PAGE_KERNEL);
282         if (ret) {
283                 struct vm_area_struct *vma;
284
285                 down_write(&current->mm->mmap_sem);
286                 vma = find_vma(current->mm, (unsigned long)ret);
287                 if (vma)
288                         vma->vm_flags |= VM_USERMAP;
289                 up_write(&current->mm->mmap_sem);
290         }
291
292         return ret;
293 }
294 EXPORT_SYMBOL(vmalloc_user);
295
296 struct page *vmalloc_to_page(const void *addr)
297 {
298         return virt_to_page(addr);
299 }
300 EXPORT_SYMBOL(vmalloc_to_page);
301
302 unsigned long vmalloc_to_pfn(const void *addr)
303 {
304         return page_to_pfn(virt_to_page(addr));
305 }
306 EXPORT_SYMBOL(vmalloc_to_pfn);
307
308 long vread(char *buf, char *addr, unsigned long count)
309 {
310         memcpy(buf, addr, count);
311         return count;
312 }
313
314 long vwrite(char *buf, char *addr, unsigned long count)
315 {
316         /* Don't allow overflow */
317         if ((unsigned long) addr + count < count)
318                 count = -(unsigned long) addr;
319
320         memcpy(addr, buf, count);
321         return(count);
322 }
323
324 /*
325  *      vmalloc  -  allocate virtually continguos memory
326  *
327  *      @size:          allocation size
328  *
329  *      Allocate enough pages to cover @size from the page level
330  *      allocator and map them into continguos kernel virtual space.
331  *
332  *      For tight control over page level allocator and protection flags
333  *      use __vmalloc() instead.
334  */
335 void *vmalloc(unsigned long size)
336 {
337        return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
338 }
339 EXPORT_SYMBOL(vmalloc);
340
341 void *vmalloc_node(unsigned long size, int node)
342 {
343         return vmalloc(size);
344 }
345 EXPORT_SYMBOL(vmalloc_node);
346
347 #ifndef PAGE_KERNEL_EXEC
348 # define PAGE_KERNEL_EXEC PAGE_KERNEL
349 #endif
350
351 /**
352  *      vmalloc_exec  -  allocate virtually contiguous, executable memory
353  *      @size:          allocation size
354  *
355  *      Kernel-internal function to allocate enough pages to cover @size
356  *      the page level allocator and map them into contiguous and
357  *      executable kernel virtual space.
358  *
359  *      For tight control over page level allocator and protection flags
360  *      use __vmalloc() instead.
361  */
362
363 void *vmalloc_exec(unsigned long size)
364 {
365         return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
366 }
367
368 /**
369  * vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
370  *      @size:          allocation size
371  *
372  *      Allocate enough 32bit PA addressable pages to cover @size from the
373  *      page level allocator and map them into continguos kernel virtual space.
374  */
375 void *vmalloc_32(unsigned long size)
376 {
377         return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
378 }
379 EXPORT_SYMBOL(vmalloc_32);
380
381 /**
382  * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
383  *      @size:          allocation size
384  *
385  * The resulting memory area is 32bit addressable and zeroed so it can be
386  * mapped to userspace without leaking data.
387  *
388  * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
389  * remap_vmalloc_range() are permissible.
390  */
391 void *vmalloc_32_user(unsigned long size)
392 {
393         /*
394          * We'll have to sort out the ZONE_DMA bits for 64-bit,
395          * but for now this can simply use vmalloc_user() directly.
396          */
397         return vmalloc_user(size);
398 }
399 EXPORT_SYMBOL(vmalloc_32_user);
400
401 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
402 {
403         BUG();
404         return NULL;
405 }
406 EXPORT_SYMBOL(vmap);
407
408 void vunmap(const void *addr)
409 {
410         BUG();
411 }
412 EXPORT_SYMBOL(vunmap);
413
414 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
415 {
416         BUG();
417         return NULL;
418 }
419 EXPORT_SYMBOL(vm_map_ram);
420
421 void vm_unmap_ram(const void *mem, unsigned int count)
422 {
423         BUG();
424 }
425 EXPORT_SYMBOL(vm_unmap_ram);
426
427 void vm_unmap_aliases(void)
428 {
429 }
430 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
431
432 /*
433  * Implement a stub for vmalloc_sync_all() if the architecture chose not to
434  * have one.
435  */
436 void  __attribute__((weak)) vmalloc_sync_all(void)
437 {
438 }
439
440 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
441                    struct page *page)
442 {
443         return -EINVAL;
444 }
445 EXPORT_SYMBOL(vm_insert_page);
446
447 /*
448  *  sys_brk() for the most part doesn't need the global kernel
449  *  lock, except when an application is doing something nasty
450  *  like trying to un-brk an area that has already been mapped
451  *  to a regular file.  in this case, the unmapping will need
452  *  to invoke file system routines that need the global lock.
453  */
454 SYSCALL_DEFINE1(brk, unsigned long, brk)
455 {
456         struct mm_struct *mm = current->mm;
457
458         if (brk < mm->start_brk || brk > mm->context.end_brk)
459                 return mm->brk;
460
461         if (mm->brk == brk)
462                 return mm->brk;
463
464         /*
465          * Always allow shrinking brk
466          */
467         if (brk <= mm->brk) {
468                 mm->brk = brk;
469                 return brk;
470         }
471
472         /*
473          * Ok, looks good - let it rip.
474          */
475         return mm->brk = brk;
476 }
477
478 /*
479  * initialise the VMA and region record slabs
480  */
481 void __init mmap_init(void)
482 {
483         int ret;
484
485         ret = percpu_counter_init(&vm_committed_as, 0);
486         VM_BUG_ON(ret);
487         vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
488 }
489
490 /*
491  * validate the region tree
492  * - the caller must hold the region lock
493  */
494 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
495 static noinline void validate_nommu_regions(void)
496 {
497         struct vm_region *region, *last;
498         struct rb_node *p, *lastp;
499
500         lastp = rb_first(&nommu_region_tree);
501         if (!lastp)
502                 return;
503
504         last = rb_entry(lastp, struct vm_region, vm_rb);
505         BUG_ON(unlikely(last->vm_end <= last->vm_start));
506         BUG_ON(unlikely(last->vm_top < last->vm_end));
507
508         while ((p = rb_next(lastp))) {
509                 region = rb_entry(p, struct vm_region, vm_rb);
510                 last = rb_entry(lastp, struct vm_region, vm_rb);
511
512                 BUG_ON(unlikely(region->vm_end <= region->vm_start));
513                 BUG_ON(unlikely(region->vm_top < region->vm_end));
514                 BUG_ON(unlikely(region->vm_start < last->vm_top));
515
516                 lastp = p;
517         }
518 }
519 #else
520 static void validate_nommu_regions(void)
521 {
522 }
523 #endif
524
525 /*
526  * add a region into the global tree
527  */
528 static void add_nommu_region(struct vm_region *region)
529 {
530         struct vm_region *pregion;
531         struct rb_node **p, *parent;
532
533         validate_nommu_regions();
534
535         parent = NULL;
536         p = &nommu_region_tree.rb_node;
537         while (*p) {
538                 parent = *p;
539                 pregion = rb_entry(parent, struct vm_region, vm_rb);
540                 if (region->vm_start < pregion->vm_start)
541                         p = &(*p)->rb_left;
542                 else if (region->vm_start > pregion->vm_start)
543                         p = &(*p)->rb_right;
544                 else if (pregion == region)
545                         return;
546                 else
547                         BUG();
548         }
549
550         rb_link_node(&region->vm_rb, parent, p);
551         rb_insert_color(&region->vm_rb, &nommu_region_tree);
552
553         validate_nommu_regions();
554 }
555
556 /*
557  * delete a region from the global tree
558  */
559 static void delete_nommu_region(struct vm_region *region)
560 {
561         BUG_ON(!nommu_region_tree.rb_node);
562
563         validate_nommu_regions();
564         rb_erase(&region->vm_rb, &nommu_region_tree);
565         validate_nommu_regions();
566 }
567
568 /*
569  * free a contiguous series of pages
570  */
571 static void free_page_series(unsigned long from, unsigned long to)
572 {
573         for (; from < to; from += PAGE_SIZE) {
574                 struct page *page = virt_to_page(from);
575
576                 kdebug("- free %lx", from);
577                 atomic_long_dec(&mmap_pages_allocated);
578                 if (page_count(page) != 1)
579                         kdebug("free page %p: refcount not one: %d",
580                                page, page_count(page));
581                 put_page(page);
582         }
583 }
584
585 /*
586  * release a reference to a region
587  * - the caller must hold the region semaphore for writing, which this releases
588  * - the region may not have been added to the tree yet, in which case vm_top
589  *   will equal vm_start
590  */
591 static void __put_nommu_region(struct vm_region *region)
592         __releases(nommu_region_sem)
593 {
594         kenter("%p{%d}", region, atomic_read(&region->vm_usage));
595
596         BUG_ON(!nommu_region_tree.rb_node);
597
598         if (atomic_dec_and_test(&region->vm_usage)) {
599                 if (region->vm_top > region->vm_start)
600                         delete_nommu_region(region);
601                 up_write(&nommu_region_sem);
602
603                 if (region->vm_file)
604                         fput(region->vm_file);
605
606                 /* IO memory and memory shared directly out of the pagecache
607                  * from ramfs/tmpfs mustn't be released here */
608                 if (region->vm_flags & VM_MAPPED_COPY) {
609                         kdebug("free series");
610                         free_page_series(region->vm_start, region->vm_top);
611                 }
612                 kmem_cache_free(vm_region_jar, region);
613         } else {
614                 up_write(&nommu_region_sem);
615         }
616 }
617
618 /*
619  * release a reference to a region
620  */
621 static void put_nommu_region(struct vm_region *region)
622 {
623         down_write(&nommu_region_sem);
624         __put_nommu_region(region);
625 }
626
627 /*
628  * update protection on a vma
629  */
630 static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
631 {
632 #ifdef CONFIG_MPU
633         struct mm_struct *mm = vma->vm_mm;
634         long start = vma->vm_start & PAGE_MASK;
635         while (start < vma->vm_end) {
636                 protect_page(mm, start, flags);
637                 start += PAGE_SIZE;
638         }
639         update_protections(mm);
640 #endif
641 }
642
643 /*
644  * add a VMA into a process's mm_struct in the appropriate place in the list
645  * and tree and add to the address space's page tree also if not an anonymous
646  * page
647  * - should be called with mm->mmap_sem held writelocked
648  */
649 static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
650 {
651         struct vm_area_struct *pvma, **pp;
652         struct address_space *mapping;
653         struct rb_node **p, *parent;
654
655         kenter(",%p", vma);
656
657         BUG_ON(!vma->vm_region);
658
659         mm->map_count++;
660         vma->vm_mm = mm;
661
662         protect_vma(vma, vma->vm_flags);
663
664         /* add the VMA to the mapping */
665         if (vma->vm_file) {
666                 mapping = vma->vm_file->f_mapping;
667
668                 flush_dcache_mmap_lock(mapping);
669                 vma_prio_tree_insert(vma, &mapping->i_mmap);
670                 flush_dcache_mmap_unlock(mapping);
671         }
672
673         /* add the VMA to the tree */
674         parent = NULL;
675         p = &mm->mm_rb.rb_node;
676         while (*p) {
677                 parent = *p;
678                 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
679
680                 /* sort by: start addr, end addr, VMA struct addr in that order
681                  * (the latter is necessary as we may get identical VMAs) */
682                 if (vma->vm_start < pvma->vm_start)
683                         p = &(*p)->rb_left;
684                 else if (vma->vm_start > pvma->vm_start)
685                         p = &(*p)->rb_right;
686                 else if (vma->vm_end < pvma->vm_end)
687                         p = &(*p)->rb_left;
688                 else if (vma->vm_end > pvma->vm_end)
689                         p = &(*p)->rb_right;
690                 else if (vma < pvma)
691                         p = &(*p)->rb_left;
692                 else if (vma > pvma)
693                         p = &(*p)->rb_right;
694                 else
695                         BUG();
696         }
697
698         rb_link_node(&vma->vm_rb, parent, p);
699         rb_insert_color(&vma->vm_rb, &mm->mm_rb);
700
701         /* add VMA to the VMA list also */
702         for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
703                 if (pvma->vm_start > vma->vm_start)
704                         break;
705                 if (pvma->vm_start < vma->vm_start)
706                         continue;
707                 if (pvma->vm_end < vma->vm_end)
708                         break;
709         }
710
711         vma->vm_next = *pp;
712         *pp = vma;
713 }
714
715 /*
716  * delete a VMA from its owning mm_struct and address space
717  */
718 static void delete_vma_from_mm(struct vm_area_struct *vma)
719 {
720         struct vm_area_struct **pp;
721         struct address_space *mapping;
722         struct mm_struct *mm = vma->vm_mm;
723
724         kenter("%p", vma);
725
726         protect_vma(vma, 0);
727
728         mm->map_count--;
729         if (mm->mmap_cache == vma)
730                 mm->mmap_cache = NULL;
731
732         /* remove the VMA from the mapping */
733         if (vma->vm_file) {
734                 mapping = vma->vm_file->f_mapping;
735
736                 flush_dcache_mmap_lock(mapping);
737                 vma_prio_tree_remove(vma, &mapping->i_mmap);
738                 flush_dcache_mmap_unlock(mapping);
739         }
740
741         /* remove from the MM's tree and list */
742         rb_erase(&vma->vm_rb, &mm->mm_rb);
743         for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
744                 if (*pp == vma) {
745                         *pp = vma->vm_next;
746                         break;
747                 }
748         }
749
750         vma->vm_mm = NULL;
751 }
752
753 /*
754  * destroy a VMA record
755  */
756 static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
757 {
758         kenter("%p", vma);
759         if (vma->vm_ops && vma->vm_ops->close)
760                 vma->vm_ops->close(vma);
761         if (vma->vm_file) {
762                 fput(vma->vm_file);
763                 if (vma->vm_flags & VM_EXECUTABLE)
764                         removed_exe_file_vma(mm);
765         }
766         put_nommu_region(vma->vm_region);
767         kmem_cache_free(vm_area_cachep, vma);
768 }
769
770 /*
771  * look up the first VMA in which addr resides, NULL if none
772  * - should be called with mm->mmap_sem at least held readlocked
773  */
774 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
775 {
776         struct vm_area_struct *vma;
777         struct rb_node *n = mm->mm_rb.rb_node;
778
779         /* check the cache first */
780         vma = mm->mmap_cache;
781         if (vma && vma->vm_start <= addr && vma->vm_end > addr)
782                 return vma;
783
784         /* trawl the tree (there may be multiple mappings in which addr
785          * resides) */
786         for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
787                 vma = rb_entry(n, struct vm_area_struct, vm_rb);
788                 if (vma->vm_start > addr)
789                         return NULL;
790                 if (vma->vm_end > addr) {
791                         mm->mmap_cache = vma;
792                         return vma;
793                 }
794         }
795
796         return NULL;
797 }
798 EXPORT_SYMBOL(find_vma);
799
800 /*
801  * find a VMA
802  * - we don't extend stack VMAs under NOMMU conditions
803  */
804 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
805 {
806         return find_vma(mm, addr);
807 }
808
809 /*
810  * expand a stack to a given address
811  * - not supported under NOMMU conditions
812  */
813 int expand_stack(struct vm_area_struct *vma, unsigned long address)
814 {
815         return -ENOMEM;
816 }
817
818 /*
819  * look up the first VMA exactly that exactly matches addr
820  * - should be called with mm->mmap_sem at least held readlocked
821  */
822 static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
823                                              unsigned long addr,
824                                              unsigned long len)
825 {
826         struct vm_area_struct *vma;
827         struct rb_node *n = mm->mm_rb.rb_node;
828         unsigned long end = addr + len;
829
830         /* check the cache first */
831         vma = mm->mmap_cache;
832         if (vma && vma->vm_start == addr && vma->vm_end == end)
833                 return vma;
834
835         /* trawl the tree (there may be multiple mappings in which addr
836          * resides) */
837         for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
838                 vma = rb_entry(n, struct vm_area_struct, vm_rb);
839                 if (vma->vm_start < addr)
840                         continue;
841                 if (vma->vm_start > addr)
842                         return NULL;
843                 if (vma->vm_end == end) {
844                         mm->mmap_cache = vma;
845                         return vma;
846                 }
847         }
848
849         return NULL;
850 }
851
852 /*
853  * determine whether a mapping should be permitted and, if so, what sort of
854  * mapping we're capable of supporting
855  */
856 static int validate_mmap_request(struct file *file,
857                                  unsigned long addr,
858                                  unsigned long len,
859                                  unsigned long prot,
860                                  unsigned long flags,
861                                  unsigned long pgoff,
862                                  unsigned long *_capabilities)
863 {
864         unsigned long capabilities, rlen;
865         unsigned long reqprot = prot;
866         int ret;
867
868         /* do the simple checks first */
869         if (flags & MAP_FIXED || addr) {
870                 printk(KERN_DEBUG
871                        "%d: Can't do fixed-address/overlay mmap of RAM\n",
872                        current->pid);
873                 return -EINVAL;
874         }
875
876         if ((flags & MAP_TYPE) != MAP_PRIVATE &&
877             (flags & MAP_TYPE) != MAP_SHARED)
878                 return -EINVAL;
879
880         if (!len)
881                 return -EINVAL;
882
883         /* Careful about overflows.. */
884         rlen = PAGE_ALIGN(len);
885         if (!rlen || rlen > TASK_SIZE)
886                 return -ENOMEM;
887
888         /* offset overflow? */
889         if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
890                 return -EOVERFLOW;
891
892         if (file) {
893                 /* validate file mapping requests */
894                 struct address_space *mapping;
895
896                 /* files must support mmap */
897                 if (!file->f_op || !file->f_op->mmap)
898                         return -ENODEV;
899
900                 /* work out if what we've got could possibly be shared
901                  * - we support chardevs that provide their own "memory"
902                  * - we support files/blockdevs that are memory backed
903                  */
904                 mapping = file->f_mapping;
905                 if (!mapping)
906                         mapping = file->f_path.dentry->d_inode->i_mapping;
907
908                 capabilities = 0;
909                 if (mapping && mapping->backing_dev_info)
910                         capabilities = mapping->backing_dev_info->capabilities;
911
912                 if (!capabilities) {
913                         /* no explicit capabilities set, so assume some
914                          * defaults */
915                         switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
916                         case S_IFREG:
917                         case S_IFBLK:
918                                 capabilities = BDI_CAP_MAP_COPY;
919                                 break;
920
921                         case S_IFCHR:
922                                 capabilities =
923                                         BDI_CAP_MAP_DIRECT |
924                                         BDI_CAP_READ_MAP |
925                                         BDI_CAP_WRITE_MAP;
926                                 break;
927
928                         default:
929                                 return -EINVAL;
930                         }
931                 }
932
933                 /* eliminate any capabilities that we can't support on this
934                  * device */
935                 if (!file->f_op->get_unmapped_area)
936                         capabilities &= ~BDI_CAP_MAP_DIRECT;
937                 if (!file->f_op->read)
938                         capabilities &= ~BDI_CAP_MAP_COPY;
939
940                 /* The file shall have been opened with read permission. */
941                 if (!(file->f_mode & FMODE_READ))
942                         return -EACCES;
943
944                 if (flags & MAP_SHARED) {
945                         /* do checks for writing, appending and locking */
946                         if ((prot & PROT_WRITE) &&
947                             !(file->f_mode & FMODE_WRITE))
948                                 return -EACCES;
949
950                         if (IS_APPEND(file->f_path.dentry->d_inode) &&
951                             (file->f_mode & FMODE_WRITE))
952                                 return -EACCES;
953
954                         if (locks_verify_locked(file->f_path.dentry->d_inode))
955                                 return -EAGAIN;
956
957                         if (!(capabilities & BDI_CAP_MAP_DIRECT))
958                                 return -ENODEV;
959
960                         if (((prot & PROT_READ)  && !(capabilities & BDI_CAP_READ_MAP))  ||
961                             ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
962                             ((prot & PROT_EXEC)  && !(capabilities & BDI_CAP_EXEC_MAP))
963                             ) {
964                                 printk("MAP_SHARED not completely supported on !MMU\n");
965                                 return -EINVAL;
966                         }
967
968                         /* we mustn't privatise shared mappings */
969                         capabilities &= ~BDI_CAP_MAP_COPY;
970                 }
971                 else {
972                         /* we're going to read the file into private memory we
973                          * allocate */
974                         if (!(capabilities & BDI_CAP_MAP_COPY))
975                                 return -ENODEV;
976
977                         /* we don't permit a private writable mapping to be
978                          * shared with the backing device */
979                         if (prot & PROT_WRITE)
980                                 capabilities &= ~BDI_CAP_MAP_DIRECT;
981                 }
982
983                 /* handle executable mappings and implied executable
984                  * mappings */
985                 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
986                         if (prot & PROT_EXEC)
987                                 return -EPERM;
988                 }
989                 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
990                         /* handle implication of PROT_EXEC by PROT_READ */
991                         if (current->personality & READ_IMPLIES_EXEC) {
992                                 if (capabilities & BDI_CAP_EXEC_MAP)
993                                         prot |= PROT_EXEC;
994                         }
995                 }
996                 else if ((prot & PROT_READ) &&
997                          (prot & PROT_EXEC) &&
998                          !(capabilities & BDI_CAP_EXEC_MAP)
999                          ) {
1000                         /* backing file is not executable, try to copy */
1001                         capabilities &= ~BDI_CAP_MAP_DIRECT;
1002                 }
1003         }
1004         else {
1005                 /* anonymous mappings are always memory backed and can be
1006                  * privately mapped
1007                  */
1008                 capabilities = BDI_CAP_MAP_COPY;
1009
1010                 /* handle PROT_EXEC implication by PROT_READ */
1011                 if ((prot & PROT_READ) &&
1012                     (current->personality & READ_IMPLIES_EXEC))
1013                         prot |= PROT_EXEC;
1014         }
1015
1016         /* allow the security API to have its say */
1017         ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
1018         if (ret < 0)
1019                 return ret;
1020
1021         /* looks okay */
1022         *_capabilities = capabilities;
1023         return 0;
1024 }
1025
1026 /*
1027  * we've determined that we can make the mapping, now translate what we
1028  * now know into VMA flags
1029  */
1030 static unsigned long determine_vm_flags(struct file *file,
1031                                         unsigned long prot,
1032                                         unsigned long flags,
1033                                         unsigned long capabilities)
1034 {
1035         unsigned long vm_flags;
1036
1037         vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
1038         vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1039         /* vm_flags |= mm->def_flags; */
1040
1041         if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1042                 /* attempt to share read-only copies of mapped file chunks */
1043                 if (file && !(prot & PROT_WRITE))
1044                         vm_flags |= VM_MAYSHARE;
1045         }
1046         else {
1047                 /* overlay a shareable mapping on the backing device or inode
1048                  * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1049                  * romfs/cramfs */
1050                 if (flags & MAP_SHARED)
1051                         vm_flags |= VM_MAYSHARE | VM_SHARED;
1052                 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1053                         vm_flags |= VM_MAYSHARE;
1054         }
1055
1056         /* refuse to let anyone share private mappings with this process if
1057          * it's being traced - otherwise breakpoints set in it may interfere
1058          * with another untraced process
1059          */
1060         if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
1061                 vm_flags &= ~VM_MAYSHARE;
1062
1063         return vm_flags;
1064 }
1065
1066 /*
1067  * set up a shared mapping on a file (the driver or filesystem provides and
1068  * pins the storage)
1069  */
1070 static int do_mmap_shared_file(struct vm_area_struct *vma)
1071 {
1072         int ret;
1073
1074         ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1075         if (ret == 0) {
1076                 vma->vm_region->vm_top = vma->vm_region->vm_end;
1077                 return ret;
1078         }
1079         if (ret != -ENOSYS)
1080                 return ret;
1081
1082         /* getting an ENOSYS error indicates that direct mmap isn't
1083          * possible (as opposed to tried but failed) so we'll fall
1084          * through to making a private copy of the data and mapping
1085          * that if we can */
1086         return -ENODEV;
1087 }
1088
1089 /*
1090  * set up a private mapping or an anonymous shared mapping
1091  */
1092 static int do_mmap_private(struct vm_area_struct *vma,
1093                            struct vm_region *region,
1094                            unsigned long len)
1095 {
1096         struct page *pages;
1097         unsigned long total, point, n, rlen;
1098         void *base;
1099         int ret, order;
1100
1101         /* invoke the file's mapping function so that it can keep track of
1102          * shared mappings on devices or memory
1103          * - VM_MAYSHARE will be set if it may attempt to share
1104          */
1105         if (vma->vm_file) {
1106                 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1107                 if (ret == 0) {
1108                         /* shouldn't return success if we're not sharing */
1109                         BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1110                         vma->vm_region->vm_top = vma->vm_region->vm_end;
1111                         return ret;
1112                 }
1113                 if (ret != -ENOSYS)
1114                         return ret;
1115
1116                 /* getting an ENOSYS error indicates that direct mmap isn't
1117                  * possible (as opposed to tried but failed) so we'll try to
1118                  * make a private copy of the data and map that instead */
1119         }
1120
1121         rlen = PAGE_ALIGN(len);
1122
1123         /* allocate some memory to hold the mapping
1124          * - note that this may not return a page-aligned address if the object
1125          *   we're allocating is smaller than a page
1126          */
1127         order = get_order(rlen);
1128         kdebug("alloc order %d for %lx", order, len);
1129
1130         pages = alloc_pages(GFP_KERNEL, order);
1131         if (!pages)
1132                 goto enomem;
1133
1134         total = 1 << order;
1135         atomic_long_add(total, &mmap_pages_allocated);
1136
1137         point = rlen >> PAGE_SHIFT;
1138
1139         /* we allocated a power-of-2 sized page set, so we may want to trim off
1140          * the excess */
1141         if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1142                 while (total > point) {
1143                         order = ilog2(total - point);
1144                         n = 1 << order;
1145                         kdebug("shave %lu/%lu @%lu", n, total - point, total);
1146                         atomic_long_sub(n, &mmap_pages_allocated);
1147                         total -= n;
1148                         set_page_refcounted(pages + total);
1149                         __free_pages(pages + total, order);
1150                 }
1151         }
1152
1153         for (point = 1; point < total; point++)
1154                 set_page_refcounted(&pages[point]);
1155
1156         base = page_address(pages);
1157         region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1158         region->vm_start = (unsigned long) base;
1159         region->vm_end   = region->vm_start + rlen;
1160         region->vm_top   = region->vm_start + (total << PAGE_SHIFT);
1161
1162         vma->vm_start = region->vm_start;
1163         vma->vm_end   = region->vm_start + len;
1164
1165         if (vma->vm_file) {
1166                 /* read the contents of a file into the copy */
1167                 mm_segment_t old_fs;
1168                 loff_t fpos;
1169
1170                 fpos = vma->vm_pgoff;
1171                 fpos <<= PAGE_SHIFT;
1172
1173                 old_fs = get_fs();
1174                 set_fs(KERNEL_DS);
1175                 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
1176                 set_fs(old_fs);
1177
1178                 if (ret < 0)
1179                         goto error_free;
1180
1181                 /* clear the last little bit */
1182                 if (ret < rlen)
1183                         memset(base + ret, 0, rlen - ret);
1184
1185         } else {
1186                 /* if it's an anonymous mapping, then just clear it */
1187                 memset(base, 0, rlen);
1188         }
1189
1190         return 0;
1191
1192 error_free:
1193         free_page_series(region->vm_start, region->vm_end);
1194         region->vm_start = vma->vm_start = 0;
1195         region->vm_end   = vma->vm_end = 0;
1196         region->vm_top   = 0;
1197         return ret;
1198
1199 enomem:
1200         printk("Allocation of length %lu from process %d (%s) failed\n",
1201                len, current->pid, current->comm);
1202         show_free_areas();
1203         return -ENOMEM;
1204 }
1205
1206 /*
1207  * handle mapping creation for uClinux
1208  */
1209 unsigned long do_mmap_pgoff(struct file *file,
1210                             unsigned long addr,
1211                             unsigned long len,
1212                             unsigned long prot,
1213                             unsigned long flags,
1214                             unsigned long pgoff)
1215 {
1216         struct vm_area_struct *vma;
1217         struct vm_region *region;
1218         struct rb_node *rb;
1219         unsigned long capabilities, vm_flags, result;
1220         int ret;
1221
1222         kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1223
1224         if (!(flags & MAP_FIXED))
1225                 addr = round_hint_to_min(addr);
1226
1227         /* decide whether we should attempt the mapping, and if so what sort of
1228          * mapping */
1229         ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1230                                     &capabilities);
1231         if (ret < 0) {
1232                 kleave(" = %d [val]", ret);
1233                 return ret;
1234         }
1235
1236         /* we've determined that we can make the mapping, now translate what we
1237          * now know into VMA flags */
1238         vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1239
1240         /* we're going to need to record the mapping */
1241         region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1242         if (!region)
1243                 goto error_getting_region;
1244
1245         vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1246         if (!vma)
1247                 goto error_getting_vma;
1248
1249         atomic_set(&region->vm_usage, 1);
1250         region->vm_flags = vm_flags;
1251         region->vm_pgoff = pgoff;
1252
1253         INIT_LIST_HEAD(&vma->anon_vma_node);
1254         vma->vm_flags = vm_flags;
1255         vma->vm_pgoff = pgoff;
1256
1257         if (file) {
1258                 region->vm_file = file;
1259                 get_file(file);
1260                 vma->vm_file = file;
1261                 get_file(file);
1262                 if (vm_flags & VM_EXECUTABLE) {
1263                         added_exe_file_vma(current->mm);
1264                         vma->vm_mm = current->mm;
1265                 }
1266         }
1267
1268         down_write(&nommu_region_sem);
1269
1270         /* if we want to share, we need to check for regions created by other
1271          * mmap() calls that overlap with our proposed mapping
1272          * - we can only share with a superset match on most regular files
1273          * - shared mappings on character devices and memory backed files are
1274          *   permitted to overlap inexactly as far as we are concerned for in
1275          *   these cases, sharing is handled in the driver or filesystem rather
1276          *   than here
1277          */
1278         if (vm_flags & VM_MAYSHARE) {
1279                 struct vm_region *pregion;
1280                 unsigned long pglen, rpglen, pgend, rpgend, start;
1281
1282                 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1283                 pgend = pgoff + pglen;
1284
1285                 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1286                         pregion = rb_entry(rb, struct vm_region, vm_rb);
1287
1288                         if (!(pregion->vm_flags & VM_MAYSHARE))
1289                                 continue;
1290
1291                         /* search for overlapping mappings on the same file */
1292                         if (pregion->vm_file->f_path.dentry->d_inode !=
1293                             file->f_path.dentry->d_inode)
1294                                 continue;
1295
1296                         if (pregion->vm_pgoff >= pgend)
1297                                 continue;
1298
1299                         rpglen = pregion->vm_end - pregion->vm_start;
1300                         rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1301                         rpgend = pregion->vm_pgoff + rpglen;
1302                         if (pgoff >= rpgend)
1303                                 continue;
1304
1305                         /* handle inexactly overlapping matches between
1306                          * mappings */
1307                         if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1308                             !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1309                                 /* new mapping is not a subset of the region */
1310                                 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1311                                         goto sharing_violation;
1312                                 continue;
1313                         }
1314
1315                         /* we've found a region we can share */
1316                         atomic_inc(&pregion->vm_usage);
1317                         vma->vm_region = pregion;
1318                         start = pregion->vm_start;
1319                         start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1320                         vma->vm_start = start;
1321                         vma->vm_end = start + len;
1322
1323                         if (pregion->vm_flags & VM_MAPPED_COPY) {
1324                                 kdebug("share copy");
1325                                 vma->vm_flags |= VM_MAPPED_COPY;
1326                         } else {
1327                                 kdebug("share mmap");
1328                                 ret = do_mmap_shared_file(vma);
1329                                 if (ret < 0) {
1330                                         vma->vm_region = NULL;
1331                                         vma->vm_start = 0;
1332                                         vma->vm_end = 0;
1333                                         atomic_dec(&pregion->vm_usage);
1334                                         pregion = NULL;
1335                                         goto error_just_free;
1336                                 }
1337                         }
1338                         fput(region->vm_file);
1339                         kmem_cache_free(vm_region_jar, region);
1340                         region = pregion;
1341                         result = start;
1342                         goto share;
1343                 }
1344
1345                 /* obtain the address at which to make a shared mapping
1346                  * - this is the hook for quasi-memory character devices to
1347                  *   tell us the location of a shared mapping
1348                  */
1349                 if (file && file->f_op->get_unmapped_area) {
1350                         addr = file->f_op->get_unmapped_area(file, addr, len,
1351                                                              pgoff, flags);
1352                         if (IS_ERR((void *) addr)) {
1353                                 ret = addr;
1354                                 if (ret != (unsigned long) -ENOSYS)
1355                                         goto error_just_free;
1356
1357                                 /* the driver refused to tell us where to site
1358                                  * the mapping so we'll have to attempt to copy
1359                                  * it */
1360                                 ret = (unsigned long) -ENODEV;
1361                                 if (!(capabilities & BDI_CAP_MAP_COPY))
1362                                         goto error_just_free;
1363
1364                                 capabilities &= ~BDI_CAP_MAP_DIRECT;
1365                         } else {
1366                                 vma->vm_start = region->vm_start = addr;
1367                                 vma->vm_end = region->vm_end = addr + len;
1368                         }
1369                 }
1370         }
1371
1372         vma->vm_region = region;
1373         add_nommu_region(region);
1374
1375         /* set up the mapping */
1376         if (file && vma->vm_flags & VM_SHARED)
1377                 ret = do_mmap_shared_file(vma);
1378         else
1379                 ret = do_mmap_private(vma, region, len);
1380         if (ret < 0)
1381                 goto error_put_region;
1382
1383         /* okay... we have a mapping; now we have to register it */
1384         result = vma->vm_start;
1385
1386         current->mm->total_vm += len >> PAGE_SHIFT;
1387
1388 share:
1389         add_vma_to_mm(current->mm, vma);
1390
1391         up_write(&nommu_region_sem);
1392
1393         if (prot & PROT_EXEC)
1394                 flush_icache_range(result, result + len);
1395
1396         kleave(" = %lx", result);
1397         return result;
1398
1399 error_put_region:
1400         __put_nommu_region(region);
1401         if (vma) {
1402                 if (vma->vm_file) {
1403                         fput(vma->vm_file);
1404                         if (vma->vm_flags & VM_EXECUTABLE)
1405                                 removed_exe_file_vma(vma->vm_mm);
1406                 }
1407                 kmem_cache_free(vm_area_cachep, vma);
1408         }
1409         kleave(" = %d [pr]", ret);
1410         return ret;
1411
1412 error_just_free:
1413         up_write(&nommu_region_sem);
1414 error:
1415         fput(region->vm_file);
1416         kmem_cache_free(vm_region_jar, region);
1417         fput(vma->vm_file);
1418         if (vma->vm_flags & VM_EXECUTABLE)
1419                 removed_exe_file_vma(vma->vm_mm);
1420         kmem_cache_free(vm_area_cachep, vma);
1421         kleave(" = %d", ret);
1422         return ret;
1423
1424 sharing_violation:
1425         up_write(&nommu_region_sem);
1426         printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1427         ret = -EINVAL;
1428         goto error;
1429
1430 error_getting_vma:
1431         kmem_cache_free(vm_region_jar, region);
1432         printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1433                " from process %d failed\n",
1434                len, current->pid);
1435         show_free_areas();
1436         return -ENOMEM;
1437
1438 error_getting_region:
1439         printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1440                " from process %d failed\n",
1441                len, current->pid);
1442         show_free_areas();
1443         return -ENOMEM;
1444 }
1445 EXPORT_SYMBOL(do_mmap_pgoff);
1446
1447 /*
1448  * split a vma into two pieces at address 'addr', a new vma is allocated either
1449  * for the first part or the tail.
1450  */
1451 int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1452               unsigned long addr, int new_below)
1453 {
1454         struct vm_area_struct *new;
1455         struct vm_region *region;
1456         unsigned long npages;
1457
1458         kenter("");
1459
1460         /* we're only permitted to split anonymous regions that have a single
1461          * owner */
1462         if (vma->vm_file ||
1463             atomic_read(&vma->vm_region->vm_usage) != 1)
1464                 return -ENOMEM;
1465
1466         if (mm->map_count >= sysctl_max_map_count)
1467                 return -ENOMEM;
1468
1469         region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1470         if (!region)
1471                 return -ENOMEM;
1472
1473         new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1474         if (!new) {
1475                 kmem_cache_free(vm_region_jar, region);
1476                 return -ENOMEM;
1477         }
1478
1479         /* most fields are the same, copy all, and then fixup */
1480         *new = *vma;
1481         *region = *vma->vm_region;
1482         new->vm_region = region;
1483
1484         npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1485
1486         if (new_below) {
1487                 region->vm_top = region->vm_end = new->vm_end = addr;
1488         } else {
1489                 region->vm_start = new->vm_start = addr;
1490                 region->vm_pgoff = new->vm_pgoff += npages;
1491         }
1492
1493         if (new->vm_ops && new->vm_ops->open)
1494                 new->vm_ops->open(new);
1495
1496         delete_vma_from_mm(vma);
1497         down_write(&nommu_region_sem);
1498         delete_nommu_region(vma->vm_region);
1499         if (new_below) {
1500                 vma->vm_region->vm_start = vma->vm_start = addr;
1501                 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1502         } else {
1503                 vma->vm_region->vm_end = vma->vm_end = addr;
1504                 vma->vm_region->vm_top = addr;
1505         }
1506         add_nommu_region(vma->vm_region);
1507         add_nommu_region(new->vm_region);
1508         up_write(&nommu_region_sem);
1509         add_vma_to_mm(mm, vma);
1510         add_vma_to_mm(mm, new);
1511         return 0;
1512 }
1513
1514 /*
1515  * shrink a VMA by removing the specified chunk from either the beginning or
1516  * the end
1517  */
1518 static int shrink_vma(struct mm_struct *mm,
1519                       struct vm_area_struct *vma,
1520                       unsigned long from, unsigned long to)
1521 {
1522         struct vm_region *region;
1523
1524         kenter("");
1525
1526         /* adjust the VMA's pointers, which may reposition it in the MM's tree
1527          * and list */
1528         delete_vma_from_mm(vma);
1529         if (from > vma->vm_start)
1530                 vma->vm_end = from;
1531         else
1532                 vma->vm_start = to;
1533         add_vma_to_mm(mm, vma);
1534
1535         /* cut the backing region down to size */
1536         region = vma->vm_region;
1537         BUG_ON(atomic_read(&region->vm_usage) != 1);
1538
1539         down_write(&nommu_region_sem);
1540         delete_nommu_region(region);
1541         if (from > region->vm_start) {
1542                 to = region->vm_top;
1543                 region->vm_top = region->vm_end = from;
1544         } else {
1545                 region->vm_start = to;
1546         }
1547         add_nommu_region(region);
1548         up_write(&nommu_region_sem);
1549
1550         free_page_series(from, to);
1551         return 0;
1552 }
1553
1554 /*
1555  * release a mapping
1556  * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1557  *   VMA, though it need not cover the whole VMA
1558  */
1559 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1560 {
1561         struct vm_area_struct *vma;
1562         struct rb_node *rb;
1563         unsigned long end = start + len;
1564         int ret;
1565
1566         kenter(",%lx,%zx", start, len);
1567
1568         if (len == 0)
1569                 return -EINVAL;
1570
1571         /* find the first potentially overlapping VMA */
1572         vma = find_vma(mm, start);
1573         if (!vma) {
1574                 static int limit = 0;
1575                 if (limit < 5) {
1576                         printk(KERN_WARNING
1577                                "munmap of memory not mmapped by process %d"
1578                                " (%s): 0x%lx-0x%lx\n",
1579                                current->pid, current->comm,
1580                                start, start + len - 1);
1581                         limit++;
1582                 }
1583                 return -EINVAL;
1584         }
1585
1586         /* we're allowed to split an anonymous VMA but not a file-backed one */
1587         if (vma->vm_file) {
1588                 do {
1589                         if (start > vma->vm_start) {
1590                                 kleave(" = -EINVAL [miss]");
1591                                 return -EINVAL;
1592                         }
1593                         if (end == vma->vm_end)
1594                                 goto erase_whole_vma;
1595                         rb = rb_next(&vma->vm_rb);
1596                         vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1597                 } while (rb);
1598                 kleave(" = -EINVAL [split file]");
1599                 return -EINVAL;
1600         } else {
1601                 /* the chunk must be a subset of the VMA found */
1602                 if (start == vma->vm_start && end == vma->vm_end)
1603                         goto erase_whole_vma;
1604                 if (start < vma->vm_start || end > vma->vm_end) {
1605                         kleave(" = -EINVAL [superset]");
1606                         return -EINVAL;
1607                 }
1608                 if (start & ~PAGE_MASK) {
1609                         kleave(" = -EINVAL [unaligned start]");
1610                         return -EINVAL;
1611                 }
1612                 if (end != vma->vm_end && end & ~PAGE_MASK) {
1613                         kleave(" = -EINVAL [unaligned split]");
1614                         return -EINVAL;
1615                 }
1616                 if (start != vma->vm_start && end != vma->vm_end) {
1617                         ret = split_vma(mm, vma, start, 1);
1618                         if (ret < 0) {
1619                                 kleave(" = %d [split]", ret);
1620                                 return ret;
1621                         }
1622                 }
1623                 return shrink_vma(mm, vma, start, end);
1624         }
1625
1626 erase_whole_vma:
1627         delete_vma_from_mm(vma);
1628         delete_vma(mm, vma);
1629         kleave(" = 0");
1630         return 0;
1631 }
1632 EXPORT_SYMBOL(do_munmap);
1633
1634 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1635 {
1636         int ret;
1637         struct mm_struct *mm = current->mm;
1638
1639         down_write(&mm->mmap_sem);
1640         ret = do_munmap(mm, addr, len);
1641         up_write(&mm->mmap_sem);
1642         return ret;
1643 }
1644
1645 /*
1646  * release all the mappings made in a process's VM space
1647  */
1648 void exit_mmap(struct mm_struct *mm)
1649 {
1650         struct vm_area_struct *vma;
1651
1652         if (!mm)
1653                 return;
1654
1655         kenter("");
1656
1657         mm->total_vm = 0;
1658
1659         while ((vma = mm->mmap)) {
1660                 mm->mmap = vma->vm_next;
1661                 delete_vma_from_mm(vma);
1662                 delete_vma(mm, vma);
1663         }
1664
1665         kleave("");
1666 }
1667
1668 unsigned long do_brk(unsigned long addr, unsigned long len)
1669 {
1670         return -ENOMEM;
1671 }
1672
1673 /*
1674  * expand (or shrink) an existing mapping, potentially moving it at the same
1675  * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1676  *
1677  * under NOMMU conditions, we only permit changing a mapping's size, and only
1678  * as long as it stays within the region allocated by do_mmap_private() and the
1679  * block is not shareable
1680  *
1681  * MREMAP_FIXED is not supported under NOMMU conditions
1682  */
1683 unsigned long do_mremap(unsigned long addr,
1684                         unsigned long old_len, unsigned long new_len,
1685                         unsigned long flags, unsigned long new_addr)
1686 {
1687         struct vm_area_struct *vma;
1688
1689         /* insanity checks first */
1690         if (old_len == 0 || new_len == 0)
1691                 return (unsigned long) -EINVAL;
1692
1693         if (addr & ~PAGE_MASK)
1694                 return -EINVAL;
1695
1696         if (flags & MREMAP_FIXED && new_addr != addr)
1697                 return (unsigned long) -EINVAL;
1698
1699         vma = find_vma_exact(current->mm, addr, old_len);
1700         if (!vma)
1701                 return (unsigned long) -EINVAL;
1702
1703         if (vma->vm_end != vma->vm_start + old_len)
1704                 return (unsigned long) -EFAULT;
1705
1706         if (vma->vm_flags & VM_MAYSHARE)
1707                 return (unsigned long) -EPERM;
1708
1709         if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1710                 return (unsigned long) -ENOMEM;
1711
1712         /* all checks complete - do it */
1713         vma->vm_end = vma->vm_start + new_len;
1714         return vma->vm_start;
1715 }
1716 EXPORT_SYMBOL(do_mremap);
1717
1718 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1719                 unsigned long, new_len, unsigned long, flags,
1720                 unsigned long, new_addr)
1721 {
1722         unsigned long ret;
1723
1724         down_write(&current->mm->mmap_sem);
1725         ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1726         up_write(&current->mm->mmap_sem);
1727         return ret;
1728 }
1729
1730 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1731                         unsigned int foll_flags)
1732 {
1733         return NULL;
1734 }
1735
1736 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1737                 unsigned long to, unsigned long size, pgprot_t prot)
1738 {
1739         vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1740         return 0;
1741 }
1742 EXPORT_SYMBOL(remap_pfn_range);
1743
1744 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1745                         unsigned long pgoff)
1746 {
1747         unsigned int size = vma->vm_end - vma->vm_start;
1748
1749         if (!(vma->vm_flags & VM_USERMAP))
1750                 return -EINVAL;
1751
1752         vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1753         vma->vm_end = vma->vm_start + size;
1754
1755         return 0;
1756 }
1757 EXPORT_SYMBOL(remap_vmalloc_range);
1758
1759 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1760 {
1761 }
1762
1763 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1764         unsigned long len, unsigned long pgoff, unsigned long flags)
1765 {
1766         return -ENOMEM;
1767 }
1768
1769 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1770 {
1771 }
1772
1773 void unmap_mapping_range(struct address_space *mapping,
1774                          loff_t const holebegin, loff_t const holelen,
1775                          int even_cows)
1776 {
1777 }
1778 EXPORT_SYMBOL(unmap_mapping_range);
1779
1780 /*
1781  * ask for an unmapped area at which to create a mapping on a file
1782  */
1783 unsigned long get_unmapped_area(struct file *file, unsigned long addr,
1784                                 unsigned long len, unsigned long pgoff,
1785                                 unsigned long flags)
1786 {
1787         unsigned long (*get_area)(struct file *, unsigned long, unsigned long,
1788                                   unsigned long, unsigned long);
1789
1790         get_area = current->mm->get_unmapped_area;
1791         if (file && file->f_op && file->f_op->get_unmapped_area)
1792                 get_area = file->f_op->get_unmapped_area;
1793
1794         if (!get_area)
1795                 return -ENOSYS;
1796
1797         return get_area(file, addr, len, pgoff, flags);
1798 }
1799 EXPORT_SYMBOL(get_unmapped_area);
1800
1801 /*
1802  * Check that a process has enough memory to allocate a new virtual
1803  * mapping. 0 means there is enough memory for the allocation to
1804  * succeed and -ENOMEM implies there is not.
1805  *
1806  * We currently support three overcommit policies, which are set via the
1807  * vm.overcommit_memory sysctl.  See Documentation/vm/overcommit-accounting
1808  *
1809  * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1810  * Additional code 2002 Jul 20 by Robert Love.
1811  *
1812  * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1813  *
1814  * Note this is a helper function intended to be used by LSMs which
1815  * wish to use this logic.
1816  */
1817 int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1818 {
1819         unsigned long free, allowed;
1820
1821         vm_acct_memory(pages);
1822
1823         /*
1824          * Sometimes we want to use more memory than we have
1825          */
1826         if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1827                 return 0;
1828
1829         if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1830                 unsigned long n;
1831
1832                 free = global_page_state(NR_FILE_PAGES);
1833                 free += nr_swap_pages;
1834
1835                 /*
1836                  * Any slabs which are created with the
1837                  * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1838                  * which are reclaimable, under pressure.  The dentry
1839                  * cache and most inode caches should fall into this
1840                  */
1841                 free += global_page_state(NR_SLAB_RECLAIMABLE);
1842
1843                 /*
1844                  * Leave the last 3% for root
1845                  */
1846                 if (!cap_sys_admin)
1847                         free -= free / 32;
1848
1849                 if (free > pages)
1850                         return 0;
1851
1852                 /*
1853                  * nr_free_pages() is very expensive on large systems,
1854                  * only call if we're about to fail.
1855                  */
1856                 n = nr_free_pages();
1857
1858                 /*
1859                  * Leave reserved pages. The pages are not for anonymous pages.
1860                  */
1861                 if (n <= totalreserve_pages)
1862                         goto error;
1863                 else
1864                         n -= totalreserve_pages;
1865
1866                 /*
1867                  * Leave the last 3% for root
1868                  */
1869                 if (!cap_sys_admin)
1870                         n -= n / 32;
1871                 free += n;
1872
1873                 if (free > pages)
1874                         return 0;
1875
1876                 goto error;
1877         }
1878
1879         allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1880         /*
1881          * Leave the last 3% for root
1882          */
1883         if (!cap_sys_admin)
1884                 allowed -= allowed / 32;
1885         allowed += total_swap_pages;
1886
1887         /* Don't let a single process grow too big:
1888            leave 3% of the size of this process for other processes */
1889         if (mm)
1890                 allowed -= mm->total_vm / 32;
1891
1892         if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1893                 return 0;
1894
1895 error:
1896         vm_unacct_memory(pages);
1897
1898         return -ENOMEM;
1899 }
1900
1901 int in_gate_area_no_task(unsigned long addr)
1902 {
1903         return 0;
1904 }
1905
1906 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1907 {
1908         BUG();
1909         return 0;
1910 }
1911 EXPORT_SYMBOL(filemap_fault);
1912
1913 /*
1914  * Access another process' address space.
1915  * - source/target buffer must be kernel space
1916  */
1917 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1918 {
1919         struct vm_area_struct *vma;
1920         struct mm_struct *mm;
1921
1922         if (addr + len < addr)
1923                 return 0;
1924
1925         mm = get_task_mm(tsk);
1926         if (!mm)
1927                 return 0;
1928
1929         down_read(&mm->mmap_sem);
1930
1931         /* the access must start within one of the target process's mappings */
1932         vma = find_vma(mm, addr);
1933         if (vma) {
1934                 /* don't overrun this mapping */
1935                 if (addr + len >= vma->vm_end)
1936                         len = vma->vm_end - addr;
1937
1938                 /* only read or write mappings where it is permitted */
1939                 if (write && vma->vm_flags & VM_MAYWRITE)
1940                         len -= copy_to_user((void *) addr, buf, len);
1941                 else if (!write && vma->vm_flags & VM_MAYREAD)
1942                         len -= copy_from_user(buf, (void *) addr, len);
1943                 else
1944                         len = 0;
1945         } else {
1946                 len = 0;
1947         }
1948
1949         up_read(&mm->mmap_sem);
1950         mmput(mm);
1951         return len;
1952 }