Add generic sys_old_mmap()
[linux-3.10.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 const struct vm_operations_struct generic_file_vm_ops = {
83 };
84
85 /*
86  * Return the total memory allocated for this pointer, not
87  * just what the caller asked for.
88  *
89  * Doesn't have to be accurate, i.e. may have races.
90  */
91 unsigned int kobjsize(const void *objp)
92 {
93         struct page *page;
94
95         /*
96          * If the object we have should not have ksize performed on it,
97          * return size of 0
98          */
99         if (!objp || !virt_addr_valid(objp))
100                 return 0;
101
102         page = virt_to_head_page(objp);
103
104         /*
105          * If the allocator sets PageSlab, we know the pointer came from
106          * kmalloc().
107          */
108         if (PageSlab(page))
109                 return ksize(objp);
110
111         /*
112          * If it's not a compound page, see if we have a matching VMA
113          * region. This test is intentionally done in reverse order,
114          * so if there's no VMA, we still fall through and hand back
115          * PAGE_SIZE for 0-order pages.
116          */
117         if (!PageCompound(page)) {
118                 struct vm_area_struct *vma;
119
120                 vma = find_vma(current->mm, (unsigned long)objp);
121                 if (vma)
122                         return vma->vm_end - vma->vm_start;
123         }
124
125         /*
126          * The ksize() function is only guaranteed to work for pointers
127          * returned by kmalloc(). So handle arbitrary pointers here.
128          */
129         return PAGE_SIZE << compound_order(page);
130 }
131
132 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
133                      unsigned long start, int nr_pages, unsigned int foll_flags,
134                      struct page **pages, struct vm_area_struct **vmas)
135 {
136         struct vm_area_struct *vma;
137         unsigned long vm_flags;
138         int i;
139
140         /* calculate required read or write permissions.
141          * If FOLL_FORCE is set, we only require the "MAY" flags.
142          */
143         vm_flags  = (foll_flags & FOLL_WRITE) ?
144                         (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
145         vm_flags &= (foll_flags & FOLL_FORCE) ?
146                         (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
147
148         for (i = 0; i < nr_pages; i++) {
149                 vma = find_extend_vma(mm, start);
150                 if (!vma)
151                         goto finish_or_fault;
152
153                 /* protect what we can, including chardevs */
154                 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
155                     !(vm_flags & vma->vm_flags))
156                         goto finish_or_fault;
157
158                 if (pages) {
159                         pages[i] = virt_to_page(start);
160                         if (pages[i])
161                                 page_cache_get(pages[i]);
162                 }
163                 if (vmas)
164                         vmas[i] = vma;
165                 start += PAGE_SIZE;
166         }
167
168         return i;
169
170 finish_or_fault:
171         return i ? : -EFAULT;
172 }
173
174 /*
175  * get a list of pages in an address range belonging to the specified process
176  * and indicate the VMA that covers each page
177  * - this is potentially dodgy as we may end incrementing the page count of a
178  *   slab page or a secondary page from a compound page
179  * - don't permit access to VMAs that don't support it, such as I/O mappings
180  */
181 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
182         unsigned long start, int nr_pages, int write, int force,
183         struct page **pages, struct vm_area_struct **vmas)
184 {
185         int flags = 0;
186
187         if (write)
188                 flags |= FOLL_WRITE;
189         if (force)
190                 flags |= FOLL_FORCE;
191
192         return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
193 }
194 EXPORT_SYMBOL(get_user_pages);
195
196 /**
197  * follow_pfn - look up PFN at a user virtual address
198  * @vma: memory mapping
199  * @address: user virtual address
200  * @pfn: location to store found PFN
201  *
202  * Only IO mappings and raw PFN mappings are allowed.
203  *
204  * Returns zero and the pfn at @pfn on success, -ve otherwise.
205  */
206 int follow_pfn(struct vm_area_struct *vma, unsigned long address,
207         unsigned long *pfn)
208 {
209         if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
210                 return -EINVAL;
211
212         *pfn = address >> PAGE_SHIFT;
213         return 0;
214 }
215 EXPORT_SYMBOL(follow_pfn);
216
217 DEFINE_RWLOCK(vmlist_lock);
218 struct vm_struct *vmlist;
219
220 void vfree(const void *addr)
221 {
222         kfree(addr);
223 }
224 EXPORT_SYMBOL(vfree);
225
226 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
227 {
228         /*
229          *  You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
230          * returns only a logical address.
231          */
232         return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
233 }
234 EXPORT_SYMBOL(__vmalloc);
235
236 void *vmalloc_user(unsigned long size)
237 {
238         void *ret;
239
240         ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
241                         PAGE_KERNEL);
242         if (ret) {
243                 struct vm_area_struct *vma;
244
245                 down_write(&current->mm->mmap_sem);
246                 vma = find_vma(current->mm, (unsigned long)ret);
247                 if (vma)
248                         vma->vm_flags |= VM_USERMAP;
249                 up_write(&current->mm->mmap_sem);
250         }
251
252         return ret;
253 }
254 EXPORT_SYMBOL(vmalloc_user);
255
256 struct page *vmalloc_to_page(const void *addr)
257 {
258         return virt_to_page(addr);
259 }
260 EXPORT_SYMBOL(vmalloc_to_page);
261
262 unsigned long vmalloc_to_pfn(const void *addr)
263 {
264         return page_to_pfn(virt_to_page(addr));
265 }
266 EXPORT_SYMBOL(vmalloc_to_pfn);
267
268 long vread(char *buf, char *addr, unsigned long count)
269 {
270         memcpy(buf, addr, count);
271         return count;
272 }
273
274 long vwrite(char *buf, char *addr, unsigned long count)
275 {
276         /* Don't allow overflow */
277         if ((unsigned long) addr + count < count)
278                 count = -(unsigned long) addr;
279
280         memcpy(addr, buf, count);
281         return(count);
282 }
283
284 /*
285  *      vmalloc  -  allocate virtually continguos memory
286  *
287  *      @size:          allocation size
288  *
289  *      Allocate enough pages to cover @size from the page level
290  *      allocator and map them into continguos kernel virtual space.
291  *
292  *      For tight control over page level allocator and protection flags
293  *      use __vmalloc() instead.
294  */
295 void *vmalloc(unsigned long size)
296 {
297        return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
298 }
299 EXPORT_SYMBOL(vmalloc);
300
301 void *vmalloc_node(unsigned long size, int node)
302 {
303         return vmalloc(size);
304 }
305 EXPORT_SYMBOL(vmalloc_node);
306
307 #ifndef PAGE_KERNEL_EXEC
308 # define PAGE_KERNEL_EXEC PAGE_KERNEL
309 #endif
310
311 /**
312  *      vmalloc_exec  -  allocate virtually contiguous, executable memory
313  *      @size:          allocation size
314  *
315  *      Kernel-internal function to allocate enough pages to cover @size
316  *      the page level allocator and map them into contiguous and
317  *      executable kernel virtual space.
318  *
319  *      For tight control over page level allocator and protection flags
320  *      use __vmalloc() instead.
321  */
322
323 void *vmalloc_exec(unsigned long size)
324 {
325         return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
326 }
327
328 /**
329  * vmalloc_32  -  allocate virtually contiguous memory (32bit addressable)
330  *      @size:          allocation size
331  *
332  *      Allocate enough 32bit PA addressable pages to cover @size from the
333  *      page level allocator and map them into continguos kernel virtual space.
334  */
335 void *vmalloc_32(unsigned long size)
336 {
337         return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
338 }
339 EXPORT_SYMBOL(vmalloc_32);
340
341 /**
342  * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
343  *      @size:          allocation size
344  *
345  * The resulting memory area is 32bit addressable and zeroed so it can be
346  * mapped to userspace without leaking data.
347  *
348  * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
349  * remap_vmalloc_range() are permissible.
350  */
351 void *vmalloc_32_user(unsigned long size)
352 {
353         /*
354          * We'll have to sort out the ZONE_DMA bits for 64-bit,
355          * but for now this can simply use vmalloc_user() directly.
356          */
357         return vmalloc_user(size);
358 }
359 EXPORT_SYMBOL(vmalloc_32_user);
360
361 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
362 {
363         BUG();
364         return NULL;
365 }
366 EXPORT_SYMBOL(vmap);
367
368 void vunmap(const void *addr)
369 {
370         BUG();
371 }
372 EXPORT_SYMBOL(vunmap);
373
374 void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
375 {
376         BUG();
377         return NULL;
378 }
379 EXPORT_SYMBOL(vm_map_ram);
380
381 void vm_unmap_ram(const void *mem, unsigned int count)
382 {
383         BUG();
384 }
385 EXPORT_SYMBOL(vm_unmap_ram);
386
387 void vm_unmap_aliases(void)
388 {
389 }
390 EXPORT_SYMBOL_GPL(vm_unmap_aliases);
391
392 /*
393  * Implement a stub for vmalloc_sync_all() if the architecture chose not to
394  * have one.
395  */
396 void  __attribute__((weak)) vmalloc_sync_all(void)
397 {
398 }
399
400 int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
401                    struct page *page)
402 {
403         return -EINVAL;
404 }
405 EXPORT_SYMBOL(vm_insert_page);
406
407 /*
408  *  sys_brk() for the most part doesn't need the global kernel
409  *  lock, except when an application is doing something nasty
410  *  like trying to un-brk an area that has already been mapped
411  *  to a regular file.  in this case, the unmapping will need
412  *  to invoke file system routines that need the global lock.
413  */
414 SYSCALL_DEFINE1(brk, unsigned long, brk)
415 {
416         struct mm_struct *mm = current->mm;
417
418         if (brk < mm->start_brk || brk > mm->context.end_brk)
419                 return mm->brk;
420
421         if (mm->brk == brk)
422                 return mm->brk;
423
424         /*
425          * Always allow shrinking brk
426          */
427         if (brk <= mm->brk) {
428                 mm->brk = brk;
429                 return brk;
430         }
431
432         /*
433          * Ok, looks good - let it rip.
434          */
435         flush_icache_range(mm->brk, brk);
436         return mm->brk = brk;
437 }
438
439 /*
440  * initialise the VMA and region record slabs
441  */
442 void __init mmap_init(void)
443 {
444         int ret;
445
446         ret = percpu_counter_init(&vm_committed_as, 0);
447         VM_BUG_ON(ret);
448         vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
449 }
450
451 /*
452  * validate the region tree
453  * - the caller must hold the region lock
454  */
455 #ifdef CONFIG_DEBUG_NOMMU_REGIONS
456 static noinline void validate_nommu_regions(void)
457 {
458         struct vm_region *region, *last;
459         struct rb_node *p, *lastp;
460
461         lastp = rb_first(&nommu_region_tree);
462         if (!lastp)
463                 return;
464
465         last = rb_entry(lastp, struct vm_region, vm_rb);
466         BUG_ON(unlikely(last->vm_end <= last->vm_start));
467         BUG_ON(unlikely(last->vm_top < last->vm_end));
468
469         while ((p = rb_next(lastp))) {
470                 region = rb_entry(p, struct vm_region, vm_rb);
471                 last = rb_entry(lastp, struct vm_region, vm_rb);
472
473                 BUG_ON(unlikely(region->vm_end <= region->vm_start));
474                 BUG_ON(unlikely(region->vm_top < region->vm_end));
475                 BUG_ON(unlikely(region->vm_start < last->vm_top));
476
477                 lastp = p;
478         }
479 }
480 #else
481 static void validate_nommu_regions(void)
482 {
483 }
484 #endif
485
486 /*
487  * add a region into the global tree
488  */
489 static void add_nommu_region(struct vm_region *region)
490 {
491         struct vm_region *pregion;
492         struct rb_node **p, *parent;
493
494         validate_nommu_regions();
495
496         parent = NULL;
497         p = &nommu_region_tree.rb_node;
498         while (*p) {
499                 parent = *p;
500                 pregion = rb_entry(parent, struct vm_region, vm_rb);
501                 if (region->vm_start < pregion->vm_start)
502                         p = &(*p)->rb_left;
503                 else if (region->vm_start > pregion->vm_start)
504                         p = &(*p)->rb_right;
505                 else if (pregion == region)
506                         return;
507                 else
508                         BUG();
509         }
510
511         rb_link_node(&region->vm_rb, parent, p);
512         rb_insert_color(&region->vm_rb, &nommu_region_tree);
513
514         validate_nommu_regions();
515 }
516
517 /*
518  * delete a region from the global tree
519  */
520 static void delete_nommu_region(struct vm_region *region)
521 {
522         BUG_ON(!nommu_region_tree.rb_node);
523
524         validate_nommu_regions();
525         rb_erase(&region->vm_rb, &nommu_region_tree);
526         validate_nommu_regions();
527 }
528
529 /*
530  * free a contiguous series of pages
531  */
532 static void free_page_series(unsigned long from, unsigned long to)
533 {
534         for (; from < to; from += PAGE_SIZE) {
535                 struct page *page = virt_to_page(from);
536
537                 kdebug("- free %lx", from);
538                 atomic_long_dec(&mmap_pages_allocated);
539                 if (page_count(page) != 1)
540                         kdebug("free page %p: refcount not one: %d",
541                                page, page_count(page));
542                 put_page(page);
543         }
544 }
545
546 /*
547  * release a reference to a region
548  * - the caller must hold the region semaphore for writing, which this releases
549  * - the region may not have been added to the tree yet, in which case vm_top
550  *   will equal vm_start
551  */
552 static void __put_nommu_region(struct vm_region *region)
553         __releases(nommu_region_sem)
554 {
555         kenter("%p{%d}", region, region->vm_usage);
556
557         BUG_ON(!nommu_region_tree.rb_node);
558
559         if (--region->vm_usage == 0) {
560                 if (region->vm_top > region->vm_start)
561                         delete_nommu_region(region);
562                 up_write(&nommu_region_sem);
563
564                 if (region->vm_file)
565                         fput(region->vm_file);
566
567                 /* IO memory and memory shared directly out of the pagecache
568                  * from ramfs/tmpfs mustn't be released here */
569                 if (region->vm_flags & VM_MAPPED_COPY) {
570                         kdebug("free series");
571                         free_page_series(region->vm_start, region->vm_top);
572                 }
573                 kmem_cache_free(vm_region_jar, region);
574         } else {
575                 up_write(&nommu_region_sem);
576         }
577 }
578
579 /*
580  * release a reference to a region
581  */
582 static void put_nommu_region(struct vm_region *region)
583 {
584         down_write(&nommu_region_sem);
585         __put_nommu_region(region);
586 }
587
588 /*
589  * update protection on a vma
590  */
591 static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
592 {
593 #ifdef CONFIG_MPU
594         struct mm_struct *mm = vma->vm_mm;
595         long start = vma->vm_start & PAGE_MASK;
596         while (start < vma->vm_end) {
597                 protect_page(mm, start, flags);
598                 start += PAGE_SIZE;
599         }
600         update_protections(mm);
601 #endif
602 }
603
604 /*
605  * add a VMA into a process's mm_struct in the appropriate place in the list
606  * and tree and add to the address space's page tree also if not an anonymous
607  * page
608  * - should be called with mm->mmap_sem held writelocked
609  */
610 static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
611 {
612         struct vm_area_struct *pvma, **pp;
613         struct address_space *mapping;
614         struct rb_node **p, *parent;
615
616         kenter(",%p", vma);
617
618         BUG_ON(!vma->vm_region);
619
620         mm->map_count++;
621         vma->vm_mm = mm;
622
623         protect_vma(vma, vma->vm_flags);
624
625         /* add the VMA to the mapping */
626         if (vma->vm_file) {
627                 mapping = vma->vm_file->f_mapping;
628
629                 flush_dcache_mmap_lock(mapping);
630                 vma_prio_tree_insert(vma, &mapping->i_mmap);
631                 flush_dcache_mmap_unlock(mapping);
632         }
633
634         /* add the VMA to the tree */
635         parent = NULL;
636         p = &mm->mm_rb.rb_node;
637         while (*p) {
638                 parent = *p;
639                 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
640
641                 /* sort by: start addr, end addr, VMA struct addr in that order
642                  * (the latter is necessary as we may get identical VMAs) */
643                 if (vma->vm_start < pvma->vm_start)
644                         p = &(*p)->rb_left;
645                 else if (vma->vm_start > pvma->vm_start)
646                         p = &(*p)->rb_right;
647                 else if (vma->vm_end < pvma->vm_end)
648                         p = &(*p)->rb_left;
649                 else if (vma->vm_end > pvma->vm_end)
650                         p = &(*p)->rb_right;
651                 else if (vma < pvma)
652                         p = &(*p)->rb_left;
653                 else if (vma > pvma)
654                         p = &(*p)->rb_right;
655                 else
656                         BUG();
657         }
658
659         rb_link_node(&vma->vm_rb, parent, p);
660         rb_insert_color(&vma->vm_rb, &mm->mm_rb);
661
662         /* add VMA to the VMA list also */
663         for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) {
664                 if (pvma->vm_start > vma->vm_start)
665                         break;
666                 if (pvma->vm_start < vma->vm_start)
667                         continue;
668                 if (pvma->vm_end < vma->vm_end)
669                         break;
670         }
671
672         vma->vm_next = *pp;
673         *pp = vma;
674 }
675
676 /*
677  * delete a VMA from its owning mm_struct and address space
678  */
679 static void delete_vma_from_mm(struct vm_area_struct *vma)
680 {
681         struct vm_area_struct **pp;
682         struct address_space *mapping;
683         struct mm_struct *mm = vma->vm_mm;
684
685         kenter("%p", vma);
686
687         protect_vma(vma, 0);
688
689         mm->map_count--;
690         if (mm->mmap_cache == vma)
691                 mm->mmap_cache = NULL;
692
693         /* remove the VMA from the mapping */
694         if (vma->vm_file) {
695                 mapping = vma->vm_file->f_mapping;
696
697                 flush_dcache_mmap_lock(mapping);
698                 vma_prio_tree_remove(vma, &mapping->i_mmap);
699                 flush_dcache_mmap_unlock(mapping);
700         }
701
702         /* remove from the MM's tree and list */
703         rb_erase(&vma->vm_rb, &mm->mm_rb);
704         for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) {
705                 if (*pp == vma) {
706                         *pp = vma->vm_next;
707                         break;
708                 }
709         }
710
711         vma->vm_mm = NULL;
712 }
713
714 /*
715  * destroy a VMA record
716  */
717 static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
718 {
719         kenter("%p", vma);
720         if (vma->vm_ops && vma->vm_ops->close)
721                 vma->vm_ops->close(vma);
722         if (vma->vm_file) {
723                 fput(vma->vm_file);
724                 if (vma->vm_flags & VM_EXECUTABLE)
725                         removed_exe_file_vma(mm);
726         }
727         put_nommu_region(vma->vm_region);
728         kmem_cache_free(vm_area_cachep, vma);
729 }
730
731 /*
732  * look up the first VMA in which addr resides, NULL if none
733  * - should be called with mm->mmap_sem at least held readlocked
734  */
735 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
736 {
737         struct vm_area_struct *vma;
738         struct rb_node *n = mm->mm_rb.rb_node;
739
740         /* check the cache first */
741         vma = mm->mmap_cache;
742         if (vma && vma->vm_start <= addr && vma->vm_end > addr)
743                 return vma;
744
745         /* trawl the tree (there may be multiple mappings in which addr
746          * resides) */
747         for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
748                 vma = rb_entry(n, struct vm_area_struct, vm_rb);
749                 if (vma->vm_start > addr)
750                         return NULL;
751                 if (vma->vm_end > addr) {
752                         mm->mmap_cache = vma;
753                         return vma;
754                 }
755         }
756
757         return NULL;
758 }
759 EXPORT_SYMBOL(find_vma);
760
761 /*
762  * find a VMA
763  * - we don't extend stack VMAs under NOMMU conditions
764  */
765 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
766 {
767         return find_vma(mm, addr & PAGE_MASK);
768 }
769
770 /*
771  * expand a stack to a given address
772  * - not supported under NOMMU conditions
773  */
774 int expand_stack(struct vm_area_struct *vma, unsigned long address)
775 {
776         return -ENOMEM;
777 }
778
779 /*
780  * look up the first VMA exactly that exactly matches addr
781  * - should be called with mm->mmap_sem at least held readlocked
782  */
783 static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
784                                              unsigned long addr,
785                                              unsigned long len)
786 {
787         struct vm_area_struct *vma;
788         struct rb_node *n = mm->mm_rb.rb_node;
789         unsigned long end = addr + len;
790
791         /* check the cache first */
792         vma = mm->mmap_cache;
793         if (vma && vma->vm_start == addr && vma->vm_end == end)
794                 return vma;
795
796         /* trawl the tree (there may be multiple mappings in which addr
797          * resides) */
798         for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) {
799                 vma = rb_entry(n, struct vm_area_struct, vm_rb);
800                 if (vma->vm_start < addr)
801                         continue;
802                 if (vma->vm_start > addr)
803                         return NULL;
804                 if (vma->vm_end == end) {
805                         mm->mmap_cache = vma;
806                         return vma;
807                 }
808         }
809
810         return NULL;
811 }
812
813 /*
814  * determine whether a mapping should be permitted and, if so, what sort of
815  * mapping we're capable of supporting
816  */
817 static int validate_mmap_request(struct file *file,
818                                  unsigned long addr,
819                                  unsigned long len,
820                                  unsigned long prot,
821                                  unsigned long flags,
822                                  unsigned long pgoff,
823                                  unsigned long *_capabilities)
824 {
825         unsigned long capabilities, rlen;
826         unsigned long reqprot = prot;
827         int ret;
828
829         /* do the simple checks first */
830         if (flags & MAP_FIXED) {
831                 printk(KERN_DEBUG
832                        "%d: Can't do fixed-address/overlay mmap of RAM\n",
833                        current->pid);
834                 return -EINVAL;
835         }
836
837         if ((flags & MAP_TYPE) != MAP_PRIVATE &&
838             (flags & MAP_TYPE) != MAP_SHARED)
839                 return -EINVAL;
840
841         if (!len)
842                 return -EINVAL;
843
844         /* Careful about overflows.. */
845         rlen = PAGE_ALIGN(len);
846         if (!rlen || rlen > TASK_SIZE)
847                 return -ENOMEM;
848
849         /* offset overflow? */
850         if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
851                 return -EOVERFLOW;
852
853         if (file) {
854                 /* validate file mapping requests */
855                 struct address_space *mapping;
856
857                 /* files must support mmap */
858                 if (!file->f_op || !file->f_op->mmap)
859                         return -ENODEV;
860
861                 /* work out if what we've got could possibly be shared
862                  * - we support chardevs that provide their own "memory"
863                  * - we support files/blockdevs that are memory backed
864                  */
865                 mapping = file->f_mapping;
866                 if (!mapping)
867                         mapping = file->f_path.dentry->d_inode->i_mapping;
868
869                 capabilities = 0;
870                 if (mapping && mapping->backing_dev_info)
871                         capabilities = mapping->backing_dev_info->capabilities;
872
873                 if (!capabilities) {
874                         /* no explicit capabilities set, so assume some
875                          * defaults */
876                         switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) {
877                         case S_IFREG:
878                         case S_IFBLK:
879                                 capabilities = BDI_CAP_MAP_COPY;
880                                 break;
881
882                         case S_IFCHR:
883                                 capabilities =
884                                         BDI_CAP_MAP_DIRECT |
885                                         BDI_CAP_READ_MAP |
886                                         BDI_CAP_WRITE_MAP;
887                                 break;
888
889                         default:
890                                 return -EINVAL;
891                         }
892                 }
893
894                 /* eliminate any capabilities that we can't support on this
895                  * device */
896                 if (!file->f_op->get_unmapped_area)
897                         capabilities &= ~BDI_CAP_MAP_DIRECT;
898                 if (!file->f_op->read)
899                         capabilities &= ~BDI_CAP_MAP_COPY;
900
901                 /* The file shall have been opened with read permission. */
902                 if (!(file->f_mode & FMODE_READ))
903                         return -EACCES;
904
905                 if (flags & MAP_SHARED) {
906                         /* do checks for writing, appending and locking */
907                         if ((prot & PROT_WRITE) &&
908                             !(file->f_mode & FMODE_WRITE))
909                                 return -EACCES;
910
911                         if (IS_APPEND(file->f_path.dentry->d_inode) &&
912                             (file->f_mode & FMODE_WRITE))
913                                 return -EACCES;
914
915                         if (locks_verify_locked(file->f_path.dentry->d_inode))
916                                 return -EAGAIN;
917
918                         if (!(capabilities & BDI_CAP_MAP_DIRECT))
919                                 return -ENODEV;
920
921                         if (((prot & PROT_READ)  && !(capabilities & BDI_CAP_READ_MAP))  ||
922                             ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
923                             ((prot & PROT_EXEC)  && !(capabilities & BDI_CAP_EXEC_MAP))
924                             ) {
925                                 printk("MAP_SHARED not completely supported on !MMU\n");
926                                 return -EINVAL;
927                         }
928
929                         /* we mustn't privatise shared mappings */
930                         capabilities &= ~BDI_CAP_MAP_COPY;
931                 }
932                 else {
933                         /* we're going to read the file into private memory we
934                          * allocate */
935                         if (!(capabilities & BDI_CAP_MAP_COPY))
936                                 return -ENODEV;
937
938                         /* we don't permit a private writable mapping to be
939                          * shared with the backing device */
940                         if (prot & PROT_WRITE)
941                                 capabilities &= ~BDI_CAP_MAP_DIRECT;
942                 }
943
944                 /* handle executable mappings and implied executable
945                  * mappings */
946                 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
947                         if (prot & PROT_EXEC)
948                                 return -EPERM;
949                 }
950                 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
951                         /* handle implication of PROT_EXEC by PROT_READ */
952                         if (current->personality & READ_IMPLIES_EXEC) {
953                                 if (capabilities & BDI_CAP_EXEC_MAP)
954                                         prot |= PROT_EXEC;
955                         }
956                 }
957                 else if ((prot & PROT_READ) &&
958                          (prot & PROT_EXEC) &&
959                          !(capabilities & BDI_CAP_EXEC_MAP)
960                          ) {
961                         /* backing file is not executable, try to copy */
962                         capabilities &= ~BDI_CAP_MAP_DIRECT;
963                 }
964         }
965         else {
966                 /* anonymous mappings are always memory backed and can be
967                  * privately mapped
968                  */
969                 capabilities = BDI_CAP_MAP_COPY;
970
971                 /* handle PROT_EXEC implication by PROT_READ */
972                 if ((prot & PROT_READ) &&
973                     (current->personality & READ_IMPLIES_EXEC))
974                         prot |= PROT_EXEC;
975         }
976
977         /* allow the security API to have its say */
978         ret = security_file_mmap(file, reqprot, prot, flags, addr, 0);
979         if (ret < 0)
980                 return ret;
981
982         /* looks okay */
983         *_capabilities = capabilities;
984         return 0;
985 }
986
987 /*
988  * we've determined that we can make the mapping, now translate what we
989  * now know into VMA flags
990  */
991 static unsigned long determine_vm_flags(struct file *file,
992                                         unsigned long prot,
993                                         unsigned long flags,
994                                         unsigned long capabilities)
995 {
996         unsigned long vm_flags;
997
998         vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
999         vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1000         /* vm_flags |= mm->def_flags; */
1001
1002         if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1003                 /* attempt to share read-only copies of mapped file chunks */
1004                 if (file && !(prot & PROT_WRITE))
1005                         vm_flags |= VM_MAYSHARE;
1006         }
1007         else {
1008                 /* overlay a shareable mapping on the backing device or inode
1009                  * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1010                  * romfs/cramfs */
1011                 if (flags & MAP_SHARED)
1012                         vm_flags |= VM_MAYSHARE | VM_SHARED;
1013                 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
1014                         vm_flags |= VM_MAYSHARE;
1015         }
1016
1017         /* refuse to let anyone share private mappings with this process if
1018          * it's being traced - otherwise breakpoints set in it may interfere
1019          * with another untraced process
1020          */
1021         if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current))
1022                 vm_flags &= ~VM_MAYSHARE;
1023
1024         return vm_flags;
1025 }
1026
1027 /*
1028  * set up a shared mapping on a file (the driver or filesystem provides and
1029  * pins the storage)
1030  */
1031 static int do_mmap_shared_file(struct vm_area_struct *vma)
1032 {
1033         int ret;
1034
1035         ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1036         if (ret == 0) {
1037                 vma->vm_region->vm_top = vma->vm_region->vm_end;
1038                 return 0;
1039         }
1040         if (ret != -ENOSYS)
1041                 return ret;
1042
1043         /* getting an ENOSYS error indicates that direct mmap isn't
1044          * possible (as opposed to tried but failed) so we'll fall
1045          * through to making a private copy of the data and mapping
1046          * that if we can */
1047         return -ENODEV;
1048 }
1049
1050 /*
1051  * set up a private mapping or an anonymous shared mapping
1052  */
1053 static int do_mmap_private(struct vm_area_struct *vma,
1054                            struct vm_region *region,
1055                            unsigned long len,
1056                            unsigned long capabilities)
1057 {
1058         struct page *pages;
1059         unsigned long total, point, n, rlen;
1060         void *base;
1061         int ret, order;
1062
1063         /* invoke the file's mapping function so that it can keep track of
1064          * shared mappings on devices or memory
1065          * - VM_MAYSHARE will be set if it may attempt to share
1066          */
1067         if (capabilities & BDI_CAP_MAP_DIRECT) {
1068                 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1069                 if (ret == 0) {
1070                         /* shouldn't return success if we're not sharing */
1071                         BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1072                         vma->vm_region->vm_top = vma->vm_region->vm_end;
1073                         return 0;
1074                 }
1075                 if (ret != -ENOSYS)
1076                         return ret;
1077
1078                 /* getting an ENOSYS error indicates that direct mmap isn't
1079                  * possible (as opposed to tried but failed) so we'll try to
1080                  * make a private copy of the data and map that instead */
1081         }
1082
1083         rlen = PAGE_ALIGN(len);
1084
1085         /* allocate some memory to hold the mapping
1086          * - note that this may not return a page-aligned address if the object
1087          *   we're allocating is smaller than a page
1088          */
1089         order = get_order(rlen);
1090         kdebug("alloc order %d for %lx", order, len);
1091
1092         pages = alloc_pages(GFP_KERNEL, order);
1093         if (!pages)
1094                 goto enomem;
1095
1096         total = 1 << order;
1097         atomic_long_add(total, &mmap_pages_allocated);
1098
1099         point = rlen >> PAGE_SHIFT;
1100
1101         /* we allocated a power-of-2 sized page set, so we may want to trim off
1102          * the excess */
1103         if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1104                 while (total > point) {
1105                         order = ilog2(total - point);
1106                         n = 1 << order;
1107                         kdebug("shave %lu/%lu @%lu", n, total - point, total);
1108                         atomic_long_sub(n, &mmap_pages_allocated);
1109                         total -= n;
1110                         set_page_refcounted(pages + total);
1111                         __free_pages(pages + total, order);
1112                 }
1113         }
1114
1115         for (point = 1; point < total; point++)
1116                 set_page_refcounted(&pages[point]);
1117
1118         base = page_address(pages);
1119         region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1120         region->vm_start = (unsigned long) base;
1121         region->vm_end   = region->vm_start + rlen;
1122         region->vm_top   = region->vm_start + (total << PAGE_SHIFT);
1123
1124         vma->vm_start = region->vm_start;
1125         vma->vm_end   = region->vm_start + len;
1126
1127         if (vma->vm_file) {
1128                 /* read the contents of a file into the copy */
1129                 mm_segment_t old_fs;
1130                 loff_t fpos;
1131
1132                 fpos = vma->vm_pgoff;
1133                 fpos <<= PAGE_SHIFT;
1134
1135                 old_fs = get_fs();
1136                 set_fs(KERNEL_DS);
1137                 ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos);
1138                 set_fs(old_fs);
1139
1140                 if (ret < 0)
1141                         goto error_free;
1142
1143                 /* clear the last little bit */
1144                 if (ret < rlen)
1145                         memset(base + ret, 0, rlen - ret);
1146
1147         }
1148
1149         return 0;
1150
1151 error_free:
1152         free_page_series(region->vm_start, region->vm_end);
1153         region->vm_start = vma->vm_start = 0;
1154         region->vm_end   = vma->vm_end = 0;
1155         region->vm_top   = 0;
1156         return ret;
1157
1158 enomem:
1159         printk("Allocation of length %lu from process %d (%s) failed\n",
1160                len, current->pid, current->comm);
1161         show_free_areas();
1162         return -ENOMEM;
1163 }
1164
1165 /*
1166  * handle mapping creation for uClinux
1167  */
1168 unsigned long do_mmap_pgoff(struct file *file,
1169                             unsigned long addr,
1170                             unsigned long len,
1171                             unsigned long prot,
1172                             unsigned long flags,
1173                             unsigned long pgoff)
1174 {
1175         struct vm_area_struct *vma;
1176         struct vm_region *region;
1177         struct rb_node *rb;
1178         unsigned long capabilities, vm_flags, result;
1179         int ret;
1180
1181         kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1182
1183         /* decide whether we should attempt the mapping, and if so what sort of
1184          * mapping */
1185         ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1186                                     &capabilities);
1187         if (ret < 0) {
1188                 kleave(" = %d [val]", ret);
1189                 return ret;
1190         }
1191
1192         /* we ignore the address hint */
1193         addr = 0;
1194
1195         /* we've determined that we can make the mapping, now translate what we
1196          * now know into VMA flags */
1197         vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1198
1199         /* we're going to need to record the mapping */
1200         region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1201         if (!region)
1202                 goto error_getting_region;
1203
1204         vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1205         if (!vma)
1206                 goto error_getting_vma;
1207
1208         region->vm_usage = 1;
1209         region->vm_flags = vm_flags;
1210         region->vm_pgoff = pgoff;
1211
1212         INIT_LIST_HEAD(&vma->anon_vma_chain);
1213         vma->vm_flags = vm_flags;
1214         vma->vm_pgoff = pgoff;
1215
1216         if (file) {
1217                 region->vm_file = file;
1218                 get_file(file);
1219                 vma->vm_file = file;
1220                 get_file(file);
1221                 if (vm_flags & VM_EXECUTABLE) {
1222                         added_exe_file_vma(current->mm);
1223                         vma->vm_mm = current->mm;
1224                 }
1225         }
1226
1227         down_write(&nommu_region_sem);
1228
1229         /* if we want to share, we need to check for regions created by other
1230          * mmap() calls that overlap with our proposed mapping
1231          * - we can only share with a superset match on most regular files
1232          * - shared mappings on character devices and memory backed files are
1233          *   permitted to overlap inexactly as far as we are concerned for in
1234          *   these cases, sharing is handled in the driver or filesystem rather
1235          *   than here
1236          */
1237         if (vm_flags & VM_MAYSHARE) {
1238                 struct vm_region *pregion;
1239                 unsigned long pglen, rpglen, pgend, rpgend, start;
1240
1241                 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1242                 pgend = pgoff + pglen;
1243
1244                 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1245                         pregion = rb_entry(rb, struct vm_region, vm_rb);
1246
1247                         if (!(pregion->vm_flags & VM_MAYSHARE))
1248                                 continue;
1249
1250                         /* search for overlapping mappings on the same file */
1251                         if (pregion->vm_file->f_path.dentry->d_inode !=
1252                             file->f_path.dentry->d_inode)
1253                                 continue;
1254
1255                         if (pregion->vm_pgoff >= pgend)
1256                                 continue;
1257
1258                         rpglen = pregion->vm_end - pregion->vm_start;
1259                         rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1260                         rpgend = pregion->vm_pgoff + rpglen;
1261                         if (pgoff >= rpgend)
1262                                 continue;
1263
1264                         /* handle inexactly overlapping matches between
1265                          * mappings */
1266                         if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1267                             !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1268                                 /* new mapping is not a subset of the region */
1269                                 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1270                                         goto sharing_violation;
1271                                 continue;
1272                         }
1273
1274                         /* we've found a region we can share */
1275                         pregion->vm_usage++;
1276                         vma->vm_region = pregion;
1277                         start = pregion->vm_start;
1278                         start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1279                         vma->vm_start = start;
1280                         vma->vm_end = start + len;
1281
1282                         if (pregion->vm_flags & VM_MAPPED_COPY) {
1283                                 kdebug("share copy");
1284                                 vma->vm_flags |= VM_MAPPED_COPY;
1285                         } else {
1286                                 kdebug("share mmap");
1287                                 ret = do_mmap_shared_file(vma);
1288                                 if (ret < 0) {
1289                                         vma->vm_region = NULL;
1290                                         vma->vm_start = 0;
1291                                         vma->vm_end = 0;
1292                                         pregion->vm_usage--;
1293                                         pregion = NULL;
1294                                         goto error_just_free;
1295                                 }
1296                         }
1297                         fput(region->vm_file);
1298                         kmem_cache_free(vm_region_jar, region);
1299                         region = pregion;
1300                         result = start;
1301                         goto share;
1302                 }
1303
1304                 /* obtain the address at which to make a shared mapping
1305                  * - this is the hook for quasi-memory character devices to
1306                  *   tell us the location of a shared mapping
1307                  */
1308                 if (capabilities & BDI_CAP_MAP_DIRECT) {
1309                         addr = file->f_op->get_unmapped_area(file, addr, len,
1310                                                              pgoff, flags);
1311                         if (IS_ERR((void *) addr)) {
1312                                 ret = addr;
1313                                 if (ret != (unsigned long) -ENOSYS)
1314                                         goto error_just_free;
1315
1316                                 /* the driver refused to tell us where to site
1317                                  * the mapping so we'll have to attempt to copy
1318                                  * it */
1319                                 ret = (unsigned long) -ENODEV;
1320                                 if (!(capabilities & BDI_CAP_MAP_COPY))
1321                                         goto error_just_free;
1322
1323                                 capabilities &= ~BDI_CAP_MAP_DIRECT;
1324                         } else {
1325                                 vma->vm_start = region->vm_start = addr;
1326                                 vma->vm_end = region->vm_end = addr + len;
1327                         }
1328                 }
1329         }
1330
1331         vma->vm_region = region;
1332
1333         /* set up the mapping
1334          * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1335          */
1336         if (file && vma->vm_flags & VM_SHARED)
1337                 ret = do_mmap_shared_file(vma);
1338         else
1339                 ret = do_mmap_private(vma, region, len, capabilities);
1340         if (ret < 0)
1341                 goto error_just_free;
1342         add_nommu_region(region);
1343
1344         /* clear anonymous mappings that don't ask for uninitialized data */
1345         if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1346                 memset((void *)region->vm_start, 0,
1347                        region->vm_end - region->vm_start);
1348
1349         /* okay... we have a mapping; now we have to register it */
1350         result = vma->vm_start;
1351
1352         current->mm->total_vm += len >> PAGE_SHIFT;
1353
1354 share:
1355         add_vma_to_mm(current->mm, vma);
1356
1357         /* we flush the region from the icache only when the first executable
1358          * mapping of it is made  */
1359         if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1360                 flush_icache_range(region->vm_start, region->vm_end);
1361                 region->vm_icache_flushed = true;
1362         }
1363
1364         up_write(&nommu_region_sem);
1365
1366         kleave(" = %lx", result);
1367         return result;
1368
1369 error_just_free:
1370         up_write(&nommu_region_sem);
1371 error:
1372         if (region->vm_file)
1373                 fput(region->vm_file);
1374         kmem_cache_free(vm_region_jar, region);
1375         if (vma->vm_file)
1376                 fput(vma->vm_file);
1377         if (vma->vm_flags & VM_EXECUTABLE)
1378                 removed_exe_file_vma(vma->vm_mm);
1379         kmem_cache_free(vm_area_cachep, vma);
1380         kleave(" = %d", ret);
1381         return ret;
1382
1383 sharing_violation:
1384         up_write(&nommu_region_sem);
1385         printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1386         ret = -EINVAL;
1387         goto error;
1388
1389 error_getting_vma:
1390         kmem_cache_free(vm_region_jar, region);
1391         printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1392                " from process %d failed\n",
1393                len, current->pid);
1394         show_free_areas();
1395         return -ENOMEM;
1396
1397 error_getting_region:
1398         printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1399                " from process %d failed\n",
1400                len, current->pid);
1401         show_free_areas();
1402         return -ENOMEM;
1403 }
1404 EXPORT_SYMBOL(do_mmap_pgoff);
1405
1406 SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1407                 unsigned long, prot, unsigned long, flags,
1408                 unsigned long, fd, unsigned long, pgoff)
1409 {
1410         struct file *file = NULL;
1411         unsigned long retval = -EBADF;
1412
1413         if (!(flags & MAP_ANONYMOUS)) {
1414                 file = fget(fd);
1415                 if (!file)
1416                         goto out;
1417         }
1418
1419         flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1420
1421         down_write(&current->mm->mmap_sem);
1422         retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1423         up_write(&current->mm->mmap_sem);
1424
1425         if (file)
1426                 fput(file);
1427 out:
1428         return retval;
1429 }
1430
1431 #ifdef __ARCH_WANT_SYS_OLD_MMAP
1432 struct mmap_arg_struct {
1433         unsigned long addr;
1434         unsigned long len;
1435         unsigned long prot;
1436         unsigned long flags;
1437         unsigned long fd;
1438         unsigned long offset;
1439 };
1440
1441 SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1442 {
1443         struct mmap_arg_struct a;
1444
1445         if (copy_from_user(&a, arg, sizeof(a)))
1446                 return -EFAULT;
1447         if (a.offset & ~PAGE_MASK)
1448                 return -EINVAL;
1449
1450         return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1451                               a.offset >> PAGE_SHIFT);
1452 }
1453 #endif /* __ARCH_WANT_SYS_OLD_MMAP */
1454
1455 /*
1456  * split a vma into two pieces at address 'addr', a new vma is allocated either
1457  * for the first part or the tail.
1458  */
1459 int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1460               unsigned long addr, int new_below)
1461 {
1462         struct vm_area_struct *new;
1463         struct vm_region *region;
1464         unsigned long npages;
1465
1466         kenter("");
1467
1468         /* we're only permitted to split anonymous regions (these should have
1469          * only a single usage on the region) */
1470         if (vma->vm_file)
1471                 return -ENOMEM;
1472
1473         if (mm->map_count >= sysctl_max_map_count)
1474                 return -ENOMEM;
1475
1476         region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1477         if (!region)
1478                 return -ENOMEM;
1479
1480         new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1481         if (!new) {
1482                 kmem_cache_free(vm_region_jar, region);
1483                 return -ENOMEM;
1484         }
1485
1486         /* most fields are the same, copy all, and then fixup */
1487         *new = *vma;
1488         *region = *vma->vm_region;
1489         new->vm_region = region;
1490
1491         npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1492
1493         if (new_below) {
1494                 region->vm_top = region->vm_end = new->vm_end = addr;
1495         } else {
1496                 region->vm_start = new->vm_start = addr;
1497                 region->vm_pgoff = new->vm_pgoff += npages;
1498         }
1499
1500         if (new->vm_ops && new->vm_ops->open)
1501                 new->vm_ops->open(new);
1502
1503         delete_vma_from_mm(vma);
1504         down_write(&nommu_region_sem);
1505         delete_nommu_region(vma->vm_region);
1506         if (new_below) {
1507                 vma->vm_region->vm_start = vma->vm_start = addr;
1508                 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1509         } else {
1510                 vma->vm_region->vm_end = vma->vm_end = addr;
1511                 vma->vm_region->vm_top = addr;
1512         }
1513         add_nommu_region(vma->vm_region);
1514         add_nommu_region(new->vm_region);
1515         up_write(&nommu_region_sem);
1516         add_vma_to_mm(mm, vma);
1517         add_vma_to_mm(mm, new);
1518         return 0;
1519 }
1520
1521 /*
1522  * shrink a VMA by removing the specified chunk from either the beginning or
1523  * the end
1524  */
1525 static int shrink_vma(struct mm_struct *mm,
1526                       struct vm_area_struct *vma,
1527                       unsigned long from, unsigned long to)
1528 {
1529         struct vm_region *region;
1530
1531         kenter("");
1532
1533         /* adjust the VMA's pointers, which may reposition it in the MM's tree
1534          * and list */
1535         delete_vma_from_mm(vma);
1536         if (from > vma->vm_start)
1537                 vma->vm_end = from;
1538         else
1539                 vma->vm_start = to;
1540         add_vma_to_mm(mm, vma);
1541
1542         /* cut the backing region down to size */
1543         region = vma->vm_region;
1544         BUG_ON(region->vm_usage != 1);
1545
1546         down_write(&nommu_region_sem);
1547         delete_nommu_region(region);
1548         if (from > region->vm_start) {
1549                 to = region->vm_top;
1550                 region->vm_top = region->vm_end = from;
1551         } else {
1552                 region->vm_start = to;
1553         }
1554         add_nommu_region(region);
1555         up_write(&nommu_region_sem);
1556
1557         free_page_series(from, to);
1558         return 0;
1559 }
1560
1561 /*
1562  * release a mapping
1563  * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1564  *   VMA, though it need not cover the whole VMA
1565  */
1566 int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1567 {
1568         struct vm_area_struct *vma;
1569         struct rb_node *rb;
1570         unsigned long end = start + len;
1571         int ret;
1572
1573         kenter(",%lx,%zx", start, len);
1574
1575         if (len == 0)
1576                 return -EINVAL;
1577
1578         /* find the first potentially overlapping VMA */
1579         vma = find_vma(mm, start);
1580         if (!vma) {
1581                 static int limit = 0;
1582                 if (limit < 5) {
1583                         printk(KERN_WARNING
1584                                "munmap of memory not mmapped by process %d"
1585                                " (%s): 0x%lx-0x%lx\n",
1586                                current->pid, current->comm,
1587                                start, start + len - 1);
1588                         limit++;
1589                 }
1590                 return -EINVAL;
1591         }
1592
1593         /* we're allowed to split an anonymous VMA but not a file-backed one */
1594         if (vma->vm_file) {
1595                 do {
1596                         if (start > vma->vm_start) {
1597                                 kleave(" = -EINVAL [miss]");
1598                                 return -EINVAL;
1599                         }
1600                         if (end == vma->vm_end)
1601                                 goto erase_whole_vma;
1602                         rb = rb_next(&vma->vm_rb);
1603                         vma = rb_entry(rb, struct vm_area_struct, vm_rb);
1604                 } while (rb);
1605                 kleave(" = -EINVAL [split file]");
1606                 return -EINVAL;
1607         } else {
1608                 /* the chunk must be a subset of the VMA found */
1609                 if (start == vma->vm_start && end == vma->vm_end)
1610                         goto erase_whole_vma;
1611                 if (start < vma->vm_start || end > vma->vm_end) {
1612                         kleave(" = -EINVAL [superset]");
1613                         return -EINVAL;
1614                 }
1615                 if (start & ~PAGE_MASK) {
1616                         kleave(" = -EINVAL [unaligned start]");
1617                         return -EINVAL;
1618                 }
1619                 if (end != vma->vm_end && end & ~PAGE_MASK) {
1620                         kleave(" = -EINVAL [unaligned split]");
1621                         return -EINVAL;
1622                 }
1623                 if (start != vma->vm_start && end != vma->vm_end) {
1624                         ret = split_vma(mm, vma, start, 1);
1625                         if (ret < 0) {
1626                                 kleave(" = %d [split]", ret);
1627                                 return ret;
1628                         }
1629                 }
1630                 return shrink_vma(mm, vma, start, end);
1631         }
1632
1633 erase_whole_vma:
1634         delete_vma_from_mm(vma);
1635         delete_vma(mm, vma);
1636         kleave(" = 0");
1637         return 0;
1638 }
1639 EXPORT_SYMBOL(do_munmap);
1640
1641 SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1642 {
1643         int ret;
1644         struct mm_struct *mm = current->mm;
1645
1646         down_write(&mm->mmap_sem);
1647         ret = do_munmap(mm, addr, len);
1648         up_write(&mm->mmap_sem);
1649         return ret;
1650 }
1651
1652 /*
1653  * release all the mappings made in a process's VM space
1654  */
1655 void exit_mmap(struct mm_struct *mm)
1656 {
1657         struct vm_area_struct *vma;
1658
1659         if (!mm)
1660                 return;
1661
1662         kenter("");
1663
1664         mm->total_vm = 0;
1665
1666         while ((vma = mm->mmap)) {
1667                 mm->mmap = vma->vm_next;
1668                 delete_vma_from_mm(vma);
1669                 delete_vma(mm, vma);
1670         }
1671
1672         kleave("");
1673 }
1674
1675 unsigned long do_brk(unsigned long addr, unsigned long len)
1676 {
1677         return -ENOMEM;
1678 }
1679
1680 /*
1681  * expand (or shrink) an existing mapping, potentially moving it at the same
1682  * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1683  *
1684  * under NOMMU conditions, we only permit changing a mapping's size, and only
1685  * as long as it stays within the region allocated by do_mmap_private() and the
1686  * block is not shareable
1687  *
1688  * MREMAP_FIXED is not supported under NOMMU conditions
1689  */
1690 unsigned long do_mremap(unsigned long addr,
1691                         unsigned long old_len, unsigned long new_len,
1692                         unsigned long flags, unsigned long new_addr)
1693 {
1694         struct vm_area_struct *vma;
1695
1696         /* insanity checks first */
1697         if (old_len == 0 || new_len == 0)
1698                 return (unsigned long) -EINVAL;
1699
1700         if (addr & ~PAGE_MASK)
1701                 return -EINVAL;
1702
1703         if (flags & MREMAP_FIXED && new_addr != addr)
1704                 return (unsigned long) -EINVAL;
1705
1706         vma = find_vma_exact(current->mm, addr, old_len);
1707         if (!vma)
1708                 return (unsigned long) -EINVAL;
1709
1710         if (vma->vm_end != vma->vm_start + old_len)
1711                 return (unsigned long) -EFAULT;
1712
1713         if (vma->vm_flags & VM_MAYSHARE)
1714                 return (unsigned long) -EPERM;
1715
1716         if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1717                 return (unsigned long) -ENOMEM;
1718
1719         /* all checks complete - do it */
1720         vma->vm_end = vma->vm_start + new_len;
1721         return vma->vm_start;
1722 }
1723 EXPORT_SYMBOL(do_mremap);
1724
1725 SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1726                 unsigned long, new_len, unsigned long, flags,
1727                 unsigned long, new_addr)
1728 {
1729         unsigned long ret;
1730
1731         down_write(&current->mm->mmap_sem);
1732         ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1733         up_write(&current->mm->mmap_sem);
1734         return ret;
1735 }
1736
1737 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1738                         unsigned int foll_flags)
1739 {
1740         return NULL;
1741 }
1742
1743 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1744                 unsigned long to, unsigned long size, pgprot_t prot)
1745 {
1746         vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1747         return 0;
1748 }
1749 EXPORT_SYMBOL(remap_pfn_range);
1750
1751 int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1752                         unsigned long pgoff)
1753 {
1754         unsigned int size = vma->vm_end - vma->vm_start;
1755
1756         if (!(vma->vm_flags & VM_USERMAP))
1757                 return -EINVAL;
1758
1759         vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1760         vma->vm_end = vma->vm_start + size;
1761
1762         return 0;
1763 }
1764 EXPORT_SYMBOL(remap_vmalloc_range);
1765
1766 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1767 {
1768 }
1769
1770 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1771         unsigned long len, unsigned long pgoff, unsigned long flags)
1772 {
1773         return -ENOMEM;
1774 }
1775
1776 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1777 {
1778 }
1779
1780 void unmap_mapping_range(struct address_space *mapping,
1781                          loff_t const holebegin, loff_t const holelen,
1782                          int even_cows)
1783 {
1784 }
1785 EXPORT_SYMBOL(unmap_mapping_range);
1786
1787 /*
1788  * Check that a process has enough memory to allocate a new virtual
1789  * mapping. 0 means there is enough memory for the allocation to
1790  * succeed and -ENOMEM implies there is not.
1791  *
1792  * We currently support three overcommit policies, which are set via the
1793  * vm.overcommit_memory sysctl.  See Documentation/vm/overcommit-accounting
1794  *
1795  * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1796  * Additional code 2002 Jul 20 by Robert Love.
1797  *
1798  * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1799  *
1800  * Note this is a helper function intended to be used by LSMs which
1801  * wish to use this logic.
1802  */
1803 int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1804 {
1805         unsigned long free, allowed;
1806
1807         vm_acct_memory(pages);
1808
1809         /*
1810          * Sometimes we want to use more memory than we have
1811          */
1812         if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1813                 return 0;
1814
1815         if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1816                 unsigned long n;
1817
1818                 free = global_page_state(NR_FILE_PAGES);
1819                 free += nr_swap_pages;
1820
1821                 /*
1822                  * Any slabs which are created with the
1823                  * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1824                  * which are reclaimable, under pressure.  The dentry
1825                  * cache and most inode caches should fall into this
1826                  */
1827                 free += global_page_state(NR_SLAB_RECLAIMABLE);
1828
1829                 /*
1830                  * Leave the last 3% for root
1831                  */
1832                 if (!cap_sys_admin)
1833                         free -= free / 32;
1834
1835                 if (free > pages)
1836                         return 0;
1837
1838                 /*
1839                  * nr_free_pages() is very expensive on large systems,
1840                  * only call if we're about to fail.
1841                  */
1842                 n = nr_free_pages();
1843
1844                 /*
1845                  * Leave reserved pages. The pages are not for anonymous pages.
1846                  */
1847                 if (n <= totalreserve_pages)
1848                         goto error;
1849                 else
1850                         n -= totalreserve_pages;
1851
1852                 /*
1853                  * Leave the last 3% for root
1854                  */
1855                 if (!cap_sys_admin)
1856                         n -= n / 32;
1857                 free += n;
1858
1859                 if (free > pages)
1860                         return 0;
1861
1862                 goto error;
1863         }
1864
1865         allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1866         /*
1867          * Leave the last 3% for root
1868          */
1869         if (!cap_sys_admin)
1870                 allowed -= allowed / 32;
1871         allowed += total_swap_pages;
1872
1873         /* Don't let a single process grow too big:
1874            leave 3% of the size of this process for other processes */
1875         if (mm)
1876                 allowed -= mm->total_vm / 32;
1877
1878         if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1879                 return 0;
1880
1881 error:
1882         vm_unacct_memory(pages);
1883
1884         return -ENOMEM;
1885 }
1886
1887 int in_gate_area_no_task(unsigned long addr)
1888 {
1889         return 0;
1890 }
1891
1892 int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1893 {
1894         BUG();
1895         return 0;
1896 }
1897 EXPORT_SYMBOL(filemap_fault);
1898
1899 /*
1900  * Access another process' address space.
1901  * - source/target buffer must be kernel space
1902  */
1903 int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
1904 {
1905         struct vm_area_struct *vma;
1906         struct mm_struct *mm;
1907
1908         if (addr + len < addr)
1909                 return 0;
1910
1911         mm = get_task_mm(tsk);
1912         if (!mm)
1913                 return 0;
1914
1915         down_read(&mm->mmap_sem);
1916
1917         /* the access must start within one of the target process's mappings */
1918         vma = find_vma(mm, addr);
1919         if (vma) {
1920                 /* don't overrun this mapping */
1921                 if (addr + len >= vma->vm_end)
1922                         len = vma->vm_end - addr;
1923
1924                 /* only read or write mappings where it is permitted */
1925                 if (write && vma->vm_flags & VM_MAYWRITE)
1926                         copy_to_user_page(vma, NULL, addr,
1927                                          (void *) addr, buf, len);
1928                 else if (!write && vma->vm_flags & VM_MAYREAD)
1929                         copy_from_user_page(vma, NULL, addr,
1930                                             buf, (void *) addr, len);
1931                 else
1932                         len = 0;
1933         } else {
1934                 len = 0;
1935         }
1936
1937         up_read(&mm->mmap_sem);
1938         mmput(mm);
1939         return len;
1940 }
1941
1942 /**
1943  * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
1944  * @inode: The inode to check
1945  * @size: The current filesize of the inode
1946  * @newsize: The proposed filesize of the inode
1947  *
1948  * Check the shared mappings on an inode on behalf of a shrinking truncate to
1949  * make sure that that any outstanding VMAs aren't broken and then shrink the
1950  * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
1951  * automatically grant mappings that are too large.
1952  */
1953 int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
1954                                 size_t newsize)
1955 {
1956         struct vm_area_struct *vma;
1957         struct prio_tree_iter iter;
1958         struct vm_region *region;
1959         pgoff_t low, high;
1960         size_t r_size, r_top;
1961
1962         low = newsize >> PAGE_SHIFT;
1963         high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1964
1965         down_write(&nommu_region_sem);
1966
1967         /* search for VMAs that fall within the dead zone */
1968         vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
1969                               low, high) {
1970                 /* found one - only interested if it's shared out of the page
1971                  * cache */
1972                 if (vma->vm_flags & VM_SHARED) {
1973                         up_write(&nommu_region_sem);
1974                         return -ETXTBSY; /* not quite true, but near enough */
1975                 }
1976         }
1977
1978         /* reduce any regions that overlap the dead zone - if in existence,
1979          * these will be pointed to by VMAs that don't overlap the dead zone
1980          *
1981          * we don't check for any regions that start beyond the EOF as there
1982          * shouldn't be any
1983          */
1984         vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap,
1985                               0, ULONG_MAX) {
1986                 if (!(vma->vm_flags & VM_SHARED))
1987                         continue;
1988
1989                 region = vma->vm_region;
1990                 r_size = region->vm_top - region->vm_start;
1991                 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
1992
1993                 if (r_top > newsize) {
1994                         region->vm_top -= r_top - newsize;
1995                         if (region->vm_end > region->vm_top)
1996                                 region->vm_end = region->vm_top;
1997                 }
1998         }
1999
2000         up_write(&nommu_region_sem);
2001         return 0;
2002 }