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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_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 = (start + PAGE_SIZE) & PAGE_MASK; |
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(¤t->mm->mmap_sem); |
246 | vma = find_vma(current->mm, (unsigned long)ret); |
247 | if (vma) |
248 | vma->vm_flags |= VM_USERMAP; |
249 | up_write(¤t->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(®ion->vm_rb, parent, p); |
512 | rb_insert_color(®ion->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(®ion->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); |
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 -ENOSYS indicates that direct mmap isn't possible (as |
1044 | * opposed to tried but failed) so we can only give a suitable error as |
1045 | * it's not possible to make a private copy if MAP_SHARED was given */ |
1046 | return -ENODEV; |
1047 | } |
1048 | |
1049 | /* |
1050 | * set up a private mapping or an anonymous shared mapping |
1051 | */ |
1052 | static int do_mmap_private(struct vm_area_struct *vma, |
1053 | struct vm_region *region, |
1054 | unsigned long len, |
1055 | unsigned long capabilities) |
1056 | { |
1057 | struct page *pages; |
1058 | unsigned long total, point, n, rlen; |
1059 | void *base; |
1060 | int ret, order; |
1061 | |
1062 | /* invoke the file's mapping function so that it can keep track of |
1063 | * shared mappings on devices or memory |
1064 | * - VM_MAYSHARE will be set if it may attempt to share |
1065 | */ |
1066 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1067 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
1068 | if (ret == 0) { |
1069 | /* shouldn't return success if we're not sharing */ |
1070 | BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
1071 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
1072 | return 0; |
1073 | } |
1074 | if (ret != -ENOSYS) |
1075 | return ret; |
1076 | |
1077 | /* getting an ENOSYS error indicates that direct mmap isn't |
1078 | * possible (as opposed to tried but failed) so we'll try to |
1079 | * make a private copy of the data and map that instead */ |
1080 | } |
1081 | |
1082 | rlen = PAGE_ALIGN(len); |
1083 | |
1084 | /* allocate some memory to hold the mapping |
1085 | * - note that this may not return a page-aligned address if the object |
1086 | * we're allocating is smaller than a page |
1087 | */ |
1088 | order = get_order(rlen); |
1089 | kdebug("alloc order %d for %lx", order, len); |
1090 | |
1091 | pages = alloc_pages(GFP_KERNEL, order); |
1092 | if (!pages) |
1093 | goto enomem; |
1094 | |
1095 | total = 1 << order; |
1096 | atomic_long_add(total, &mmap_pages_allocated); |
1097 | |
1098 | point = rlen >> PAGE_SHIFT; |
1099 | |
1100 | /* we allocated a power-of-2 sized page set, so we may want to trim off |
1101 | * the excess */ |
1102 | if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) { |
1103 | while (total > point) { |
1104 | order = ilog2(total - point); |
1105 | n = 1 << order; |
1106 | kdebug("shave %lu/%lu @%lu", n, total - point, total); |
1107 | atomic_long_sub(n, &mmap_pages_allocated); |
1108 | total -= n; |
1109 | set_page_refcounted(pages + total); |
1110 | __free_pages(pages + total, order); |
1111 | } |
1112 | } |
1113 | |
1114 | for (point = 1; point < total; point++) |
1115 | set_page_refcounted(&pages[point]); |
1116 | |
1117 | base = page_address(pages); |
1118 | region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; |
1119 | region->vm_start = (unsigned long) base; |
1120 | region->vm_end = region->vm_start + rlen; |
1121 | region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
1122 | |
1123 | vma->vm_start = region->vm_start; |
1124 | vma->vm_end = region->vm_start + len; |
1125 | |
1126 | if (vma->vm_file) { |
1127 | /* read the contents of a file into the copy */ |
1128 | mm_segment_t old_fs; |
1129 | loff_t fpos; |
1130 | |
1131 | fpos = vma->vm_pgoff; |
1132 | fpos <<= PAGE_SHIFT; |
1133 | |
1134 | old_fs = get_fs(); |
1135 | set_fs(KERNEL_DS); |
1136 | ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos); |
1137 | set_fs(old_fs); |
1138 | |
1139 | if (ret < 0) |
1140 | goto error_free; |
1141 | |
1142 | /* clear the last little bit */ |
1143 | if (ret < rlen) |
1144 | memset(base + ret, 0, rlen - ret); |
1145 | |
1146 | } |
1147 | |
1148 | return 0; |
1149 | |
1150 | error_free: |
1151 | free_page_series(region->vm_start, region->vm_end); |
1152 | region->vm_start = vma->vm_start = 0; |
1153 | region->vm_end = vma->vm_end = 0; |
1154 | region->vm_top = 0; |
1155 | return ret; |
1156 | |
1157 | enomem: |
1158 | printk("Allocation of length %lu from process %d (%s) failed\n", |
1159 | len, current->pid, current->comm); |
1160 | show_free_areas(); |
1161 | return -ENOMEM; |
1162 | } |
1163 | |
1164 | /* |
1165 | * handle mapping creation for uClinux |
1166 | */ |
1167 | unsigned long do_mmap_pgoff(struct file *file, |
1168 | unsigned long addr, |
1169 | unsigned long len, |
1170 | unsigned long prot, |
1171 | unsigned long flags, |
1172 | unsigned long pgoff) |
1173 | { |
1174 | struct vm_area_struct *vma; |
1175 | struct vm_region *region; |
1176 | struct rb_node *rb; |
1177 | unsigned long capabilities, vm_flags, result; |
1178 | int ret; |
1179 | |
1180 | kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); |
1181 | |
1182 | /* decide whether we should attempt the mapping, and if so what sort of |
1183 | * mapping */ |
1184 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, |
1185 | &capabilities); |
1186 | if (ret < 0) { |
1187 | kleave(" = %d [val]", ret); |
1188 | return ret; |
1189 | } |
1190 | |
1191 | /* we ignore the address hint */ |
1192 | addr = 0; |
1193 | |
1194 | /* we've determined that we can make the mapping, now translate what we |
1195 | * now know into VMA flags */ |
1196 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); |
1197 | |
1198 | /* we're going to need to record the mapping */ |
1199 | region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); |
1200 | if (!region) |
1201 | goto error_getting_region; |
1202 | |
1203 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1204 | if (!vma) |
1205 | goto error_getting_vma; |
1206 | |
1207 | region->vm_usage = 1; |
1208 | region->vm_flags = vm_flags; |
1209 | region->vm_pgoff = pgoff; |
1210 | |
1211 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1212 | vma->vm_flags = vm_flags; |
1213 | vma->vm_pgoff = pgoff; |
1214 | |
1215 | if (file) { |
1216 | region->vm_file = file; |
1217 | get_file(file); |
1218 | vma->vm_file = file; |
1219 | get_file(file); |
1220 | if (vm_flags & VM_EXECUTABLE) { |
1221 | added_exe_file_vma(current->mm); |
1222 | vma->vm_mm = current->mm; |
1223 | } |
1224 | } |
1225 | |
1226 | down_write(&nommu_region_sem); |
1227 | |
1228 | /* if we want to share, we need to check for regions created by other |
1229 | * mmap() calls that overlap with our proposed mapping |
1230 | * - we can only share with a superset match on most regular files |
1231 | * - shared mappings on character devices and memory backed files are |
1232 | * permitted to overlap inexactly as far as we are concerned for in |
1233 | * these cases, sharing is handled in the driver or filesystem rather |
1234 | * than here |
1235 | */ |
1236 | if (vm_flags & VM_MAYSHARE) { |
1237 | struct vm_region *pregion; |
1238 | unsigned long pglen, rpglen, pgend, rpgend, start; |
1239 | |
1240 | pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1241 | pgend = pgoff + pglen; |
1242 | |
1243 | for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
1244 | pregion = rb_entry(rb, struct vm_region, vm_rb); |
1245 | |
1246 | if (!(pregion->vm_flags & VM_MAYSHARE)) |
1247 | continue; |
1248 | |
1249 | /* search for overlapping mappings on the same file */ |
1250 | if (pregion->vm_file->f_path.dentry->d_inode != |
1251 | file->f_path.dentry->d_inode) |
1252 | continue; |
1253 | |
1254 | if (pregion->vm_pgoff >= pgend) |
1255 | continue; |
1256 | |
1257 | rpglen = pregion->vm_end - pregion->vm_start; |
1258 | rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1259 | rpgend = pregion->vm_pgoff + rpglen; |
1260 | if (pgoff >= rpgend) |
1261 | continue; |
1262 | |
1263 | /* handle inexactly overlapping matches between |
1264 | * mappings */ |
1265 | if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && |
1266 | !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { |
1267 | /* new mapping is not a subset of the region */ |
1268 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
1269 | goto sharing_violation; |
1270 | continue; |
1271 | } |
1272 | |
1273 | /* we've found a region we can share */ |
1274 | pregion->vm_usage++; |
1275 | vma->vm_region = pregion; |
1276 | start = pregion->vm_start; |
1277 | start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; |
1278 | vma->vm_start = start; |
1279 | vma->vm_end = start + len; |
1280 | |
1281 | if (pregion->vm_flags & VM_MAPPED_COPY) { |
1282 | kdebug("share copy"); |
1283 | vma->vm_flags |= VM_MAPPED_COPY; |
1284 | } else { |
1285 | kdebug("share mmap"); |
1286 | ret = do_mmap_shared_file(vma); |
1287 | if (ret < 0) { |
1288 | vma->vm_region = NULL; |
1289 | vma->vm_start = 0; |
1290 | vma->vm_end = 0; |
1291 | pregion->vm_usage--; |
1292 | pregion = NULL; |
1293 | goto error_just_free; |
1294 | } |
1295 | } |
1296 | fput(region->vm_file); |
1297 | kmem_cache_free(vm_region_jar, region); |
1298 | region = pregion; |
1299 | result = start; |
1300 | goto share; |
1301 | } |
1302 | |
1303 | /* obtain the address at which to make a shared mapping |
1304 | * - this is the hook for quasi-memory character devices to |
1305 | * tell us the location of a shared mapping |
1306 | */ |
1307 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1308 | addr = file->f_op->get_unmapped_area(file, addr, len, |
1309 | pgoff, flags); |
1310 | if (IS_ERR((void *) addr)) { |
1311 | ret = addr; |
1312 | if (ret != (unsigned long) -ENOSYS) |
1313 | goto error_just_free; |
1314 | |
1315 | /* the driver refused to tell us where to site |
1316 | * the mapping so we'll have to attempt to copy |
1317 | * it */ |
1318 | ret = (unsigned long) -ENODEV; |
1319 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
1320 | goto error_just_free; |
1321 | |
1322 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1323 | } else { |
1324 | vma->vm_start = region->vm_start = addr; |
1325 | vma->vm_end = region->vm_end = addr + len; |
1326 | } |
1327 | } |
1328 | } |
1329 | |
1330 | vma->vm_region = region; |
1331 | |
1332 | /* set up the mapping |
1333 | * - the region is filled in if BDI_CAP_MAP_DIRECT is still set |
1334 | */ |
1335 | if (file && vma->vm_flags & VM_SHARED) |
1336 | ret = do_mmap_shared_file(vma); |
1337 | else |
1338 | ret = do_mmap_private(vma, region, len, capabilities); |
1339 | if (ret < 0) |
1340 | goto error_just_free; |
1341 | add_nommu_region(region); |
1342 | |
1343 | /* clear anonymous mappings that don't ask for uninitialized data */ |
1344 | if (!vma->vm_file && !(flags & MAP_UNINITIALIZED)) |
1345 | memset((void *)region->vm_start, 0, |
1346 | region->vm_end - region->vm_start); |
1347 | |
1348 | /* okay... we have a mapping; now we have to register it */ |
1349 | result = vma->vm_start; |
1350 | |
1351 | current->mm->total_vm += len >> PAGE_SHIFT; |
1352 | |
1353 | share: |
1354 | add_vma_to_mm(current->mm, vma); |
1355 | |
1356 | /* we flush the region from the icache only when the first executable |
1357 | * mapping of it is made */ |
1358 | if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { |
1359 | flush_icache_range(region->vm_start, region->vm_end); |
1360 | region->vm_icache_flushed = true; |
1361 | } |
1362 | |
1363 | up_write(&nommu_region_sem); |
1364 | |
1365 | kleave(" = %lx", result); |
1366 | return result; |
1367 | |
1368 | error_just_free: |
1369 | up_write(&nommu_region_sem); |
1370 | error: |
1371 | if (region->vm_file) |
1372 | fput(region->vm_file); |
1373 | kmem_cache_free(vm_region_jar, region); |
1374 | if (vma->vm_file) |
1375 | fput(vma->vm_file); |
1376 | if (vma->vm_flags & VM_EXECUTABLE) |
1377 | removed_exe_file_vma(vma->vm_mm); |
1378 | kmem_cache_free(vm_area_cachep, vma); |
1379 | kleave(" = %d", ret); |
1380 | return ret; |
1381 | |
1382 | sharing_violation: |
1383 | up_write(&nommu_region_sem); |
1384 | printk(KERN_WARNING "Attempt to share mismatched mappings\n"); |
1385 | ret = -EINVAL; |
1386 | goto error; |
1387 | |
1388 | error_getting_vma: |
1389 | kmem_cache_free(vm_region_jar, region); |
1390 | printk(KERN_WARNING "Allocation of vma for %lu byte allocation" |
1391 | " from process %d failed\n", |
1392 | len, current->pid); |
1393 | show_free_areas(); |
1394 | return -ENOMEM; |
1395 | |
1396 | error_getting_region: |
1397 | printk(KERN_WARNING "Allocation of vm region for %lu byte allocation" |
1398 | " from process %d failed\n", |
1399 | len, current->pid); |
1400 | show_free_areas(); |
1401 | return -ENOMEM; |
1402 | } |
1403 | EXPORT_SYMBOL(do_mmap_pgoff); |
1404 | |
1405 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1406 | unsigned long, prot, unsigned long, flags, |
1407 | unsigned long, fd, unsigned long, pgoff) |
1408 | { |
1409 | struct file *file = NULL; |
1410 | unsigned long retval = -EBADF; |
1411 | |
1412 | if (!(flags & MAP_ANONYMOUS)) { |
1413 | file = fget(fd); |
1414 | if (!file) |
1415 | goto out; |
1416 | } |
1417 | |
1418 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); |
1419 | |
1420 | down_write(¤t->mm->mmap_sem); |
1421 | retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
1422 | up_write(¤t->mm->mmap_sem); |
1423 | |
1424 | if (file) |
1425 | fput(file); |
1426 | out: |
1427 | return retval; |
1428 | } |
1429 | |
1430 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1431 | struct mmap_arg_struct { |
1432 | unsigned long addr; |
1433 | unsigned long len; |
1434 | unsigned long prot; |
1435 | unsigned long flags; |
1436 | unsigned long fd; |
1437 | unsigned long offset; |
1438 | }; |
1439 | |
1440 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) |
1441 | { |
1442 | struct mmap_arg_struct a; |
1443 | |
1444 | if (copy_from_user(&a, arg, sizeof(a))) |
1445 | return -EFAULT; |
1446 | if (a.offset & ~PAGE_MASK) |
1447 | return -EINVAL; |
1448 | |
1449 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
1450 | a.offset >> PAGE_SHIFT); |
1451 | } |
1452 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
1453 | |
1454 | /* |
1455 | * split a vma into two pieces at address 'addr', a new vma is allocated either |
1456 | * for the first part or the tail. |
1457 | */ |
1458 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
1459 | unsigned long addr, int new_below) |
1460 | { |
1461 | struct vm_area_struct *new; |
1462 | struct vm_region *region; |
1463 | unsigned long npages; |
1464 | |
1465 | kenter(""); |
1466 | |
1467 | /* we're only permitted to split anonymous regions (these should have |
1468 | * only a single usage on the region) */ |
1469 | if (vma->vm_file) |
1470 | return -ENOMEM; |
1471 | |
1472 | if (mm->map_count >= sysctl_max_map_count) |
1473 | return -ENOMEM; |
1474 | |
1475 | region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
1476 | if (!region) |
1477 | return -ENOMEM; |
1478 | |
1479 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1480 | if (!new) { |
1481 | kmem_cache_free(vm_region_jar, region); |
1482 | return -ENOMEM; |
1483 | } |
1484 | |
1485 | /* most fields are the same, copy all, and then fixup */ |
1486 | *new = *vma; |
1487 | *region = *vma->vm_region; |
1488 | new->vm_region = region; |
1489 | |
1490 | npages = (addr - vma->vm_start) >> PAGE_SHIFT; |
1491 | |
1492 | if (new_below) { |
1493 | region->vm_top = region->vm_end = new->vm_end = addr; |
1494 | } else { |
1495 | region->vm_start = new->vm_start = addr; |
1496 | region->vm_pgoff = new->vm_pgoff += npages; |
1497 | } |
1498 | |
1499 | if (new->vm_ops && new->vm_ops->open) |
1500 | new->vm_ops->open(new); |
1501 | |
1502 | delete_vma_from_mm(vma); |
1503 | down_write(&nommu_region_sem); |
1504 | delete_nommu_region(vma->vm_region); |
1505 | if (new_below) { |
1506 | vma->vm_region->vm_start = vma->vm_start = addr; |
1507 | vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; |
1508 | } else { |
1509 | vma->vm_region->vm_end = vma->vm_end = addr; |
1510 | vma->vm_region->vm_top = addr; |
1511 | } |
1512 | add_nommu_region(vma->vm_region); |
1513 | add_nommu_region(new->vm_region); |
1514 | up_write(&nommu_region_sem); |
1515 | add_vma_to_mm(mm, vma); |
1516 | add_vma_to_mm(mm, new); |
1517 | return 0; |
1518 | } |
1519 | |
1520 | /* |
1521 | * shrink a VMA by removing the specified chunk from either the beginning or |
1522 | * the end |
1523 | */ |
1524 | static int shrink_vma(struct mm_struct *mm, |
1525 | struct vm_area_struct *vma, |
1526 | unsigned long from, unsigned long to) |
1527 | { |
1528 | struct vm_region *region; |
1529 | |
1530 | kenter(""); |
1531 | |
1532 | /* adjust the VMA's pointers, which may reposition it in the MM's tree |
1533 | * and list */ |
1534 | delete_vma_from_mm(vma); |
1535 | if (from > vma->vm_start) |
1536 | vma->vm_end = from; |
1537 | else |
1538 | vma->vm_start = to; |
1539 | add_vma_to_mm(mm, vma); |
1540 | |
1541 | /* cut the backing region down to size */ |
1542 | region = vma->vm_region; |
1543 | BUG_ON(region->vm_usage != 1); |
1544 | |
1545 | down_write(&nommu_region_sem); |
1546 | delete_nommu_region(region); |
1547 | if (from > region->vm_start) { |
1548 | to = region->vm_top; |
1549 | region->vm_top = region->vm_end = from; |
1550 | } else { |
1551 | region->vm_start = to; |
1552 | } |
1553 | add_nommu_region(region); |
1554 | up_write(&nommu_region_sem); |
1555 | |
1556 | free_page_series(from, to); |
1557 | return 0; |
1558 | } |
1559 | |
1560 | /* |
1561 | * release a mapping |
1562 | * - under NOMMU conditions the chunk to be unmapped must be backed by a single |
1563 | * VMA, though it need not cover the whole VMA |
1564 | */ |
1565 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
1566 | { |
1567 | struct vm_area_struct *vma; |
1568 | struct rb_node *rb; |
1569 | unsigned long end = start + len; |
1570 | int ret; |
1571 | |
1572 | kenter(",%lx,%zx", start, len); |
1573 | |
1574 | if (len == 0) |
1575 | return -EINVAL; |
1576 | |
1577 | /* find the first potentially overlapping VMA */ |
1578 | vma = find_vma(mm, start); |
1579 | if (!vma) { |
1580 | static int limit = 0; |
1581 | if (limit < 5) { |
1582 | printk(KERN_WARNING |
1583 | "munmap of memory not mmapped by process %d" |
1584 | " (%s): 0x%lx-0x%lx\n", |
1585 | current->pid, current->comm, |
1586 | start, start + len - 1); |
1587 | limit++; |
1588 | } |
1589 | return -EINVAL; |
1590 | } |
1591 | |
1592 | /* we're allowed to split an anonymous VMA but not a file-backed one */ |
1593 | if (vma->vm_file) { |
1594 | do { |
1595 | if (start > vma->vm_start) { |
1596 | kleave(" = -EINVAL [miss]"); |
1597 | return -EINVAL; |
1598 | } |
1599 | if (end == vma->vm_end) |
1600 | goto erase_whole_vma; |
1601 | rb = rb_next(&vma->vm_rb); |
1602 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); |
1603 | } while (rb); |
1604 | kleave(" = -EINVAL [split file]"); |
1605 | return -EINVAL; |
1606 | } else { |
1607 | /* the chunk must be a subset of the VMA found */ |
1608 | if (start == vma->vm_start && end == vma->vm_end) |
1609 | goto erase_whole_vma; |
1610 | if (start < vma->vm_start || end > vma->vm_end) { |
1611 | kleave(" = -EINVAL [superset]"); |
1612 | return -EINVAL; |
1613 | } |
1614 | if (start & ~PAGE_MASK) { |
1615 | kleave(" = -EINVAL [unaligned start]"); |
1616 | return -EINVAL; |
1617 | } |
1618 | if (end != vma->vm_end && end & ~PAGE_MASK) { |
1619 | kleave(" = -EINVAL [unaligned split]"); |
1620 | return -EINVAL; |
1621 | } |
1622 | if (start != vma->vm_start && end != vma->vm_end) { |
1623 | ret = split_vma(mm, vma, start, 1); |
1624 | if (ret < 0) { |
1625 | kleave(" = %d [split]", ret); |
1626 | return ret; |
1627 | } |
1628 | } |
1629 | return shrink_vma(mm, vma, start, end); |
1630 | } |
1631 | |
1632 | erase_whole_vma: |
1633 | delete_vma_from_mm(vma); |
1634 | delete_vma(mm, vma); |
1635 | kleave(" = 0"); |
1636 | return 0; |
1637 | } |
1638 | EXPORT_SYMBOL(do_munmap); |
1639 | |
1640 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
1641 | { |
1642 | int ret; |
1643 | struct mm_struct *mm = current->mm; |
1644 | |
1645 | down_write(&mm->mmap_sem); |
1646 | ret = do_munmap(mm, addr, len); |
1647 | up_write(&mm->mmap_sem); |
1648 | return ret; |
1649 | } |
1650 | |
1651 | /* |
1652 | * release all the mappings made in a process's VM space |
1653 | */ |
1654 | void exit_mmap(struct mm_struct *mm) |
1655 | { |
1656 | struct vm_area_struct *vma; |
1657 | |
1658 | if (!mm) |
1659 | return; |
1660 | |
1661 | kenter(""); |
1662 | |
1663 | mm->total_vm = 0; |
1664 | |
1665 | while ((vma = mm->mmap)) { |
1666 | mm->mmap = vma->vm_next; |
1667 | delete_vma_from_mm(vma); |
1668 | delete_vma(mm, vma); |
1669 | } |
1670 | |
1671 | kleave(""); |
1672 | } |
1673 | |
1674 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1675 | { |
1676 | return -ENOMEM; |
1677 | } |
1678 | |
1679 | /* |
1680 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1681 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
1682 | * |
1683 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
1684 | * as long as it stays within the region allocated by do_mmap_private() and the |
1685 | * block is not shareable |
1686 | * |
1687 | * MREMAP_FIXED is not supported under NOMMU conditions |
1688 | */ |
1689 | unsigned long do_mremap(unsigned long addr, |
1690 | unsigned long old_len, unsigned long new_len, |
1691 | unsigned long flags, unsigned long new_addr) |
1692 | { |
1693 | struct vm_area_struct *vma; |
1694 | |
1695 | /* insanity checks first */ |
1696 | if (old_len == 0 || new_len == 0) |
1697 | return (unsigned long) -EINVAL; |
1698 | |
1699 | if (addr & ~PAGE_MASK) |
1700 | return -EINVAL; |
1701 | |
1702 | if (flags & MREMAP_FIXED && new_addr != addr) |
1703 | return (unsigned long) -EINVAL; |
1704 | |
1705 | vma = find_vma_exact(current->mm, addr, old_len); |
1706 | if (!vma) |
1707 | return (unsigned long) -EINVAL; |
1708 | |
1709 | if (vma->vm_end != vma->vm_start + old_len) |
1710 | return (unsigned long) -EFAULT; |
1711 | |
1712 | if (vma->vm_flags & VM_MAYSHARE) |
1713 | return (unsigned long) -EPERM; |
1714 | |
1715 | if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1716 | return (unsigned long) -ENOMEM; |
1717 | |
1718 | /* all checks complete - do it */ |
1719 | vma->vm_end = vma->vm_start + new_len; |
1720 | return vma->vm_start; |
1721 | } |
1722 | EXPORT_SYMBOL(do_mremap); |
1723 | |
1724 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
1725 | unsigned long, new_len, unsigned long, flags, |
1726 | unsigned long, new_addr) |
1727 | { |
1728 | unsigned long ret; |
1729 | |
1730 | down_write(¤t->mm->mmap_sem); |
1731 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
1732 | up_write(¤t->mm->mmap_sem); |
1733 | return ret; |
1734 | } |
1735 | |
1736 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
1737 | unsigned int foll_flags) |
1738 | { |
1739 | return NULL; |
1740 | } |
1741 | |
1742 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
1743 | unsigned long to, unsigned long size, pgprot_t prot) |
1744 | { |
1745 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
1746 | return 0; |
1747 | } |
1748 | EXPORT_SYMBOL(remap_pfn_range); |
1749 | |
1750 | int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
1751 | unsigned long pgoff) |
1752 | { |
1753 | unsigned int size = vma->vm_end - vma->vm_start; |
1754 | |
1755 | if (!(vma->vm_flags & VM_USERMAP)) |
1756 | return -EINVAL; |
1757 | |
1758 | vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); |
1759 | vma->vm_end = vma->vm_start + size; |
1760 | |
1761 | return 0; |
1762 | } |
1763 | EXPORT_SYMBOL(remap_vmalloc_range); |
1764 | |
1765 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
1766 | { |
1767 | } |
1768 | |
1769 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, |
1770 | unsigned long len, unsigned long pgoff, unsigned long flags) |
1771 | { |
1772 | return -ENOMEM; |
1773 | } |
1774 | |
1775 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1776 | { |
1777 | } |
1778 | |
1779 | void unmap_mapping_range(struct address_space *mapping, |
1780 | loff_t const holebegin, loff_t const holelen, |
1781 | int even_cows) |
1782 | { |
1783 | } |
1784 | EXPORT_SYMBOL(unmap_mapping_range); |
1785 | |
1786 | /* |
1787 | * Check that a process has enough memory to allocate a new virtual |
1788 | * mapping. 0 means there is enough memory for the allocation to |
1789 | * succeed and -ENOMEM implies there is not. |
1790 | * |
1791 | * We currently support three overcommit policies, which are set via the |
1792 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
1793 | * |
1794 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
1795 | * Additional code 2002 Jul 20 by Robert Love. |
1796 | * |
1797 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
1798 | * |
1799 | * Note this is a helper function intended to be used by LSMs which |
1800 | * wish to use this logic. |
1801 | */ |
1802 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1803 | { |
1804 | unsigned long free, allowed; |
1805 | |
1806 | vm_acct_memory(pages); |
1807 | |
1808 | /* |
1809 | * Sometimes we want to use more memory than we have |
1810 | */ |
1811 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
1812 | return 0; |
1813 | |
1814 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
1815 | unsigned long n; |
1816 | |
1817 | free = global_page_state(NR_FILE_PAGES); |
1818 | free += nr_swap_pages; |
1819 | |
1820 | /* |
1821 | * Any slabs which are created with the |
1822 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
1823 | * which are reclaimable, under pressure. The dentry |
1824 | * cache and most inode caches should fall into this |
1825 | */ |
1826 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1827 | |
1828 | /* |
1829 | * Leave the last 3% for root |
1830 | */ |
1831 | if (!cap_sys_admin) |
1832 | free -= free / 32; |
1833 | |
1834 | if (free > pages) |
1835 | return 0; |
1836 | |
1837 | /* |
1838 | * nr_free_pages() is very expensive on large systems, |
1839 | * only call if we're about to fail. |
1840 | */ |
1841 | n = nr_free_pages(); |
1842 | |
1843 | /* |
1844 | * Leave reserved pages. The pages are not for anonymous pages. |
1845 | */ |
1846 | if (n <= totalreserve_pages) |
1847 | goto error; |
1848 | else |
1849 | n -= totalreserve_pages; |
1850 | |
1851 | /* |
1852 | * Leave the last 3% for root |
1853 | */ |
1854 | if (!cap_sys_admin) |
1855 | n -= n / 32; |
1856 | free += n; |
1857 | |
1858 | if (free > pages) |
1859 | return 0; |
1860 | |
1861 | goto error; |
1862 | } |
1863 | |
1864 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; |
1865 | /* |
1866 | * Leave the last 3% for root |
1867 | */ |
1868 | if (!cap_sys_admin) |
1869 | allowed -= allowed / 32; |
1870 | allowed += total_swap_pages; |
1871 | |
1872 | /* Don't let a single process grow too big: |
1873 | leave 3% of the size of this process for other processes */ |
1874 | if (mm) |
1875 | allowed -= mm->total_vm / 32; |
1876 | |
1877 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1878 | return 0; |
1879 | |
1880 | error: |
1881 | vm_unacct_memory(pages); |
1882 | |
1883 | return -ENOMEM; |
1884 | } |
1885 | |
1886 | int in_gate_area_no_task(unsigned long addr) |
1887 | { |
1888 | return 0; |
1889 | } |
1890 | |
1891 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1892 | { |
1893 | BUG(); |
1894 | return 0; |
1895 | } |
1896 | EXPORT_SYMBOL(filemap_fault); |
1897 | |
1898 | /* |
1899 | * Access another process' address space. |
1900 | * - source/target buffer must be kernel space |
1901 | */ |
1902 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) |
1903 | { |
1904 | struct vm_area_struct *vma; |
1905 | struct mm_struct *mm; |
1906 | |
1907 | if (addr + len < addr) |
1908 | return 0; |
1909 | |
1910 | mm = get_task_mm(tsk); |
1911 | if (!mm) |
1912 | return 0; |
1913 | |
1914 | down_read(&mm->mmap_sem); |
1915 | |
1916 | /* the access must start within one of the target process's mappings */ |
1917 | vma = find_vma(mm, addr); |
1918 | if (vma) { |
1919 | /* don't overrun this mapping */ |
1920 | if (addr + len >= vma->vm_end) |
1921 | len = vma->vm_end - addr; |
1922 | |
1923 | /* only read or write mappings where it is permitted */ |
1924 | if (write && vma->vm_flags & VM_MAYWRITE) |
1925 | copy_to_user_page(vma, NULL, addr, |
1926 | (void *) addr, buf, len); |
1927 | else if (!write && vma->vm_flags & VM_MAYREAD) |
1928 | copy_from_user_page(vma, NULL, addr, |
1929 | buf, (void *) addr, len); |
1930 | else |
1931 | len = 0; |
1932 | } else { |
1933 | len = 0; |
1934 | } |
1935 | |
1936 | up_read(&mm->mmap_sem); |
1937 | mmput(mm); |
1938 | return len; |
1939 | } |
1940 | |
1941 | /** |
1942 | * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode |
1943 | * @inode: The inode to check |
1944 | * @size: The current filesize of the inode |
1945 | * @newsize: The proposed filesize of the inode |
1946 | * |
1947 | * Check the shared mappings on an inode on behalf of a shrinking truncate to |
1948 | * make sure that that any outstanding VMAs aren't broken and then shrink the |
1949 | * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't |
1950 | * automatically grant mappings that are too large. |
1951 | */ |
1952 | int nommu_shrink_inode_mappings(struct inode *inode, size_t size, |
1953 | size_t newsize) |
1954 | { |
1955 | struct vm_area_struct *vma; |
1956 | struct prio_tree_iter iter; |
1957 | struct vm_region *region; |
1958 | pgoff_t low, high; |
1959 | size_t r_size, r_top; |
1960 | |
1961 | low = newsize >> PAGE_SHIFT; |
1962 | high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1963 | |
1964 | down_write(&nommu_region_sem); |
1965 | |
1966 | /* search for VMAs that fall within the dead zone */ |
1967 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, |
1968 | low, high) { |
1969 | /* found one - only interested if it's shared out of the page |
1970 | * cache */ |
1971 | if (vma->vm_flags & VM_SHARED) { |
1972 | up_write(&nommu_region_sem); |
1973 | return -ETXTBSY; /* not quite true, but near enough */ |
1974 | } |
1975 | } |
1976 | |
1977 | /* reduce any regions that overlap the dead zone - if in existence, |
1978 | * these will be pointed to by VMAs that don't overlap the dead zone |
1979 | * |
1980 | * we don't check for any regions that start beyond the EOF as there |
1981 | * shouldn't be any |
1982 | */ |
1983 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, |
1984 | 0, ULONG_MAX) { |
1985 | if (!(vma->vm_flags & VM_SHARED)) |
1986 | continue; |
1987 | |
1988 | region = vma->vm_region; |
1989 | r_size = region->vm_top - region->vm_start; |
1990 | r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; |
1991 | |
1992 | if (r_top > newsize) { |
1993 | region->vm_top -= r_top - newsize; |
1994 | if (region->vm_end > region->vm_top) |
1995 | region->vm_end = region->vm_top; |
1996 | } |
1997 | } |
1998 | |
1999 | up_write(&nommu_region_sem); |
2000 | return 0; |
2001 | } |
2002 |
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Tags:
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od-2011-09-18
v2.6.34-rc5
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