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Source at commit 6c17a31f1fc515425221067cb3ece599c09dbc5d created 12 years 8 months ago. By Werner Almesberger, atusb, atben: moved from spi/ to ieee802154/; renamed atusb to spi_atusb | |
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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) 2007-2010 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 | #include <linux/audit.h> |
33 | |
34 | #include <asm/uaccess.h> |
35 | #include <asm/tlb.h> |
36 | #include <asm/tlbflush.h> |
37 | #include <asm/mmu_context.h> |
38 | #include "internal.h" |
39 | |
40 | #if 0 |
41 | #define kenter(FMT, ...) \ |
42 | printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__) |
43 | #define kleave(FMT, ...) \ |
44 | printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__) |
45 | #define kdebug(FMT, ...) \ |
46 | printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__) |
47 | #else |
48 | #define kenter(FMT, ...) \ |
49 | no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__) |
50 | #define kleave(FMT, ...) \ |
51 | no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__) |
52 | #define kdebug(FMT, ...) \ |
53 | no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__) |
54 | #endif |
55 | |
56 | void *high_memory; |
57 | struct page *mem_map; |
58 | unsigned long max_mapnr; |
59 | unsigned long num_physpages; |
60 | unsigned long highest_memmap_pfn; |
61 | struct percpu_counter vm_committed_as; |
62 | int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ |
63 | int sysctl_overcommit_ratio = 50; /* default is 50% */ |
64 | int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; |
65 | int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; |
66 | int heap_stack_gap = 0; |
67 | |
68 | atomic_long_t mmap_pages_allocated; |
69 | |
70 | EXPORT_SYMBOL(mem_map); |
71 | EXPORT_SYMBOL(num_physpages); |
72 | |
73 | /* list of mapped, potentially shareable regions */ |
74 | static struct kmem_cache *vm_region_jar; |
75 | struct rb_root nommu_region_tree = RB_ROOT; |
76 | DECLARE_RWSEM(nommu_region_sem); |
77 | |
78 | const struct vm_operations_struct generic_file_vm_ops = { |
79 | }; |
80 | |
81 | /* |
82 | * Return the total memory allocated for this pointer, not |
83 | * just what the caller asked for. |
84 | * |
85 | * Doesn't have to be accurate, i.e. may have races. |
86 | */ |
87 | unsigned int kobjsize(const void *objp) |
88 | { |
89 | struct page *page; |
90 | |
91 | /* |
92 | * If the object we have should not have ksize performed on it, |
93 | * return size of 0 |
94 | */ |
95 | if (!objp || !virt_addr_valid(objp)) |
96 | return 0; |
97 | |
98 | page = virt_to_head_page(objp); |
99 | |
100 | /* |
101 | * If the allocator sets PageSlab, we know the pointer came from |
102 | * kmalloc(). |
103 | */ |
104 | if (PageSlab(page)) |
105 | return ksize(objp); |
106 | |
107 | /* |
108 | * If it's not a compound page, see if we have a matching VMA |
109 | * region. This test is intentionally done in reverse order, |
110 | * so if there's no VMA, we still fall through and hand back |
111 | * PAGE_SIZE for 0-order pages. |
112 | */ |
113 | if (!PageCompound(page)) { |
114 | struct vm_area_struct *vma; |
115 | |
116 | vma = find_vma(current->mm, (unsigned long)objp); |
117 | if (vma) |
118 | return vma->vm_end - vma->vm_start; |
119 | } |
120 | |
121 | /* |
122 | * The ksize() function is only guaranteed to work for pointers |
123 | * returned by kmalloc(). So handle arbitrary pointers here. |
124 | */ |
125 | return PAGE_SIZE << compound_order(page); |
126 | } |
127 | |
128 | int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
129 | unsigned long start, int nr_pages, unsigned int foll_flags, |
130 | struct page **pages, struct vm_area_struct **vmas, |
131 | int *retry) |
132 | { |
133 | struct vm_area_struct *vma; |
134 | unsigned long vm_flags; |
135 | int i; |
136 | |
137 | /* calculate required read or write permissions. |
138 | * If FOLL_FORCE is set, we only require the "MAY" flags. |
139 | */ |
140 | vm_flags = (foll_flags & FOLL_WRITE) ? |
141 | (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
142 | vm_flags &= (foll_flags & FOLL_FORCE) ? |
143 | (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
144 | |
145 | for (i = 0; i < nr_pages; i++) { |
146 | vma = find_vma(mm, start); |
147 | if (!vma) |
148 | goto finish_or_fault; |
149 | |
150 | /* protect what we can, including chardevs */ |
151 | if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) || |
152 | !(vm_flags & vma->vm_flags)) |
153 | goto finish_or_fault; |
154 | |
155 | if (pages) { |
156 | pages[i] = virt_to_page(start); |
157 | if (pages[i]) |
158 | page_cache_get(pages[i]); |
159 | } |
160 | if (vmas) |
161 | vmas[i] = vma; |
162 | start = (start + PAGE_SIZE) & PAGE_MASK; |
163 | } |
164 | |
165 | return i; |
166 | |
167 | finish_or_fault: |
168 | return i ? : -EFAULT; |
169 | } |
170 | |
171 | /* |
172 | * get a list of pages in an address range belonging to the specified process |
173 | * and indicate the VMA that covers each page |
174 | * - this is potentially dodgy as we may end incrementing the page count of a |
175 | * slab page or a secondary page from a compound page |
176 | * - don't permit access to VMAs that don't support it, such as I/O mappings |
177 | */ |
178 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
179 | unsigned long start, int nr_pages, int write, int force, |
180 | struct page **pages, struct vm_area_struct **vmas) |
181 | { |
182 | int flags = 0; |
183 | |
184 | if (write) |
185 | flags |= FOLL_WRITE; |
186 | if (force) |
187 | flags |= FOLL_FORCE; |
188 | |
189 | return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas, |
190 | NULL); |
191 | } |
192 | EXPORT_SYMBOL(get_user_pages); |
193 | |
194 | /** |
195 | * follow_pfn - look up PFN at a user virtual address |
196 | * @vma: memory mapping |
197 | * @address: user virtual address |
198 | * @pfn: location to store found PFN |
199 | * |
200 | * Only IO mappings and raw PFN mappings are allowed. |
201 | * |
202 | * Returns zero and the pfn at @pfn on success, -ve otherwise. |
203 | */ |
204 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, |
205 | unsigned long *pfn) |
206 | { |
207 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
208 | return -EINVAL; |
209 | |
210 | *pfn = address >> PAGE_SHIFT; |
211 | return 0; |
212 | } |
213 | EXPORT_SYMBOL(follow_pfn); |
214 | |
215 | DEFINE_RWLOCK(vmlist_lock); |
216 | struct vm_struct *vmlist; |
217 | |
218 | void vfree(const void *addr) |
219 | { |
220 | kfree(addr); |
221 | } |
222 | EXPORT_SYMBOL(vfree); |
223 | |
224 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
225 | { |
226 | /* |
227 | * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() |
228 | * returns only a logical address. |
229 | */ |
230 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
231 | } |
232 | EXPORT_SYMBOL(__vmalloc); |
233 | |
234 | void *vmalloc_user(unsigned long size) |
235 | { |
236 | void *ret; |
237 | |
238 | ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, |
239 | PAGE_KERNEL); |
240 | if (ret) { |
241 | struct vm_area_struct *vma; |
242 | |
243 | down_write(¤t->mm->mmap_sem); |
244 | vma = find_vma(current->mm, (unsigned long)ret); |
245 | if (vma) |
246 | vma->vm_flags |= VM_USERMAP; |
247 | up_write(¤t->mm->mmap_sem); |
248 | } |
249 | |
250 | return ret; |
251 | } |
252 | EXPORT_SYMBOL(vmalloc_user); |
253 | |
254 | struct page *vmalloc_to_page(const void *addr) |
255 | { |
256 | return virt_to_page(addr); |
257 | } |
258 | EXPORT_SYMBOL(vmalloc_to_page); |
259 | |
260 | unsigned long vmalloc_to_pfn(const void *addr) |
261 | { |
262 | return page_to_pfn(virt_to_page(addr)); |
263 | } |
264 | EXPORT_SYMBOL(vmalloc_to_pfn); |
265 | |
266 | long vread(char *buf, char *addr, unsigned long count) |
267 | { |
268 | memcpy(buf, addr, count); |
269 | return count; |
270 | } |
271 | |
272 | long vwrite(char *buf, char *addr, unsigned long count) |
273 | { |
274 | /* Don't allow overflow */ |
275 | if ((unsigned long) addr + count < count) |
276 | count = -(unsigned long) addr; |
277 | |
278 | memcpy(addr, buf, count); |
279 | return(count); |
280 | } |
281 | |
282 | /* |
283 | * vmalloc - allocate virtually continguos memory |
284 | * |
285 | * @size: allocation size |
286 | * |
287 | * Allocate enough pages to cover @size from the page level |
288 | * allocator and map them into continguos kernel virtual space. |
289 | * |
290 | * For tight control over page level allocator and protection flags |
291 | * use __vmalloc() instead. |
292 | */ |
293 | void *vmalloc(unsigned long size) |
294 | { |
295 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); |
296 | } |
297 | EXPORT_SYMBOL(vmalloc); |
298 | |
299 | /* |
300 | * vzalloc - allocate virtually continguos memory with zero fill |
301 | * |
302 | * @size: allocation size |
303 | * |
304 | * Allocate enough pages to cover @size from the page level |
305 | * allocator and map them into continguos kernel virtual space. |
306 | * The memory allocated is set to zero. |
307 | * |
308 | * For tight control over page level allocator and protection flags |
309 | * use __vmalloc() instead. |
310 | */ |
311 | void *vzalloc(unsigned long size) |
312 | { |
313 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, |
314 | PAGE_KERNEL); |
315 | } |
316 | EXPORT_SYMBOL(vzalloc); |
317 | |
318 | /** |
319 | * vmalloc_node - allocate memory on a specific node |
320 | * @size: allocation size |
321 | * @node: numa node |
322 | * |
323 | * Allocate enough pages to cover @size from the page level |
324 | * allocator and map them into contiguous kernel virtual space. |
325 | * |
326 | * For tight control over page level allocator and protection flags |
327 | * use __vmalloc() instead. |
328 | */ |
329 | void *vmalloc_node(unsigned long size, int node) |
330 | { |
331 | return vmalloc(size); |
332 | } |
333 | EXPORT_SYMBOL(vmalloc_node); |
334 | |
335 | /** |
336 | * vzalloc_node - allocate memory on a specific node with zero fill |
337 | * @size: allocation size |
338 | * @node: numa node |
339 | * |
340 | * Allocate enough pages to cover @size from the page level |
341 | * allocator and map them into contiguous kernel virtual space. |
342 | * The memory allocated is set to zero. |
343 | * |
344 | * For tight control over page level allocator and protection flags |
345 | * use __vmalloc() instead. |
346 | */ |
347 | void *vzalloc_node(unsigned long size, int node) |
348 | { |
349 | return vzalloc(size); |
350 | } |
351 | EXPORT_SYMBOL(vzalloc_node); |
352 | |
353 | #ifndef PAGE_KERNEL_EXEC |
354 | # define PAGE_KERNEL_EXEC PAGE_KERNEL |
355 | #endif |
356 | |
357 | /** |
358 | * vmalloc_exec - allocate virtually contiguous, executable memory |
359 | * @size: allocation size |
360 | * |
361 | * Kernel-internal function to allocate enough pages to cover @size |
362 | * the page level allocator and map them into contiguous and |
363 | * executable kernel virtual space. |
364 | * |
365 | * For tight control over page level allocator and protection flags |
366 | * use __vmalloc() instead. |
367 | */ |
368 | |
369 | void *vmalloc_exec(unsigned long size) |
370 | { |
371 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); |
372 | } |
373 | |
374 | /** |
375 | * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) |
376 | * @size: allocation size |
377 | * |
378 | * Allocate enough 32bit PA addressable pages to cover @size from the |
379 | * page level allocator and map them into continguos kernel virtual space. |
380 | */ |
381 | void *vmalloc_32(unsigned long size) |
382 | { |
383 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); |
384 | } |
385 | EXPORT_SYMBOL(vmalloc_32); |
386 | |
387 | /** |
388 | * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory |
389 | * @size: allocation size |
390 | * |
391 | * The resulting memory area is 32bit addressable and zeroed so it can be |
392 | * mapped to userspace without leaking data. |
393 | * |
394 | * VM_USERMAP is set on the corresponding VMA so that subsequent calls to |
395 | * remap_vmalloc_range() are permissible. |
396 | */ |
397 | void *vmalloc_32_user(unsigned long size) |
398 | { |
399 | /* |
400 | * We'll have to sort out the ZONE_DMA bits for 64-bit, |
401 | * but for now this can simply use vmalloc_user() directly. |
402 | */ |
403 | return vmalloc_user(size); |
404 | } |
405 | EXPORT_SYMBOL(vmalloc_32_user); |
406 | |
407 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) |
408 | { |
409 | BUG(); |
410 | return NULL; |
411 | } |
412 | EXPORT_SYMBOL(vmap); |
413 | |
414 | void vunmap(const void *addr) |
415 | { |
416 | BUG(); |
417 | } |
418 | EXPORT_SYMBOL(vunmap); |
419 | |
420 | void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) |
421 | { |
422 | BUG(); |
423 | return NULL; |
424 | } |
425 | EXPORT_SYMBOL(vm_map_ram); |
426 | |
427 | void vm_unmap_ram(const void *mem, unsigned int count) |
428 | { |
429 | BUG(); |
430 | } |
431 | EXPORT_SYMBOL(vm_unmap_ram); |
432 | |
433 | void vm_unmap_aliases(void) |
434 | { |
435 | } |
436 | EXPORT_SYMBOL_GPL(vm_unmap_aliases); |
437 | |
438 | /* |
439 | * Implement a stub for vmalloc_sync_all() if the architecture chose not to |
440 | * have one. |
441 | */ |
442 | void __attribute__((weak)) vmalloc_sync_all(void) |
443 | { |
444 | } |
445 | |
446 | /** |
447 | * alloc_vm_area - allocate a range of kernel address space |
448 | * @size: size of the area |
449 | * |
450 | * Returns: NULL on failure, vm_struct on success |
451 | * |
452 | * This function reserves a range of kernel address space, and |
453 | * allocates pagetables to map that range. No actual mappings |
454 | * are created. If the kernel address space is not shared |
455 | * between processes, it syncs the pagetable across all |
456 | * processes. |
457 | */ |
458 | struct vm_struct *alloc_vm_area(size_t size) |
459 | { |
460 | BUG(); |
461 | return NULL; |
462 | } |
463 | EXPORT_SYMBOL_GPL(alloc_vm_area); |
464 | |
465 | void free_vm_area(struct vm_struct *area) |
466 | { |
467 | BUG(); |
468 | } |
469 | EXPORT_SYMBOL_GPL(free_vm_area); |
470 | |
471 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
472 | struct page *page) |
473 | { |
474 | return -EINVAL; |
475 | } |
476 | EXPORT_SYMBOL(vm_insert_page); |
477 | |
478 | /* |
479 | * sys_brk() for the most part doesn't need the global kernel |
480 | * lock, except when an application is doing something nasty |
481 | * like trying to un-brk an area that has already been mapped |
482 | * to a regular file. in this case, the unmapping will need |
483 | * to invoke file system routines that need the global lock. |
484 | */ |
485 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
486 | { |
487 | struct mm_struct *mm = current->mm; |
488 | |
489 | if (brk < mm->start_brk || brk > mm->context.end_brk) |
490 | return mm->brk; |
491 | |
492 | if (mm->brk == brk) |
493 | return mm->brk; |
494 | |
495 | /* |
496 | * Always allow shrinking brk |
497 | */ |
498 | if (brk <= mm->brk) { |
499 | mm->brk = brk; |
500 | return brk; |
501 | } |
502 | |
503 | /* |
504 | * Ok, looks good - let it rip. |
505 | */ |
506 | flush_icache_range(mm->brk, brk); |
507 | return mm->brk = brk; |
508 | } |
509 | |
510 | /* |
511 | * initialise the VMA and region record slabs |
512 | */ |
513 | void __init mmap_init(void) |
514 | { |
515 | int ret; |
516 | |
517 | ret = percpu_counter_init(&vm_committed_as, 0); |
518 | VM_BUG_ON(ret); |
519 | vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC); |
520 | } |
521 | |
522 | /* |
523 | * validate the region tree |
524 | * - the caller must hold the region lock |
525 | */ |
526 | #ifdef CONFIG_DEBUG_NOMMU_REGIONS |
527 | static noinline void validate_nommu_regions(void) |
528 | { |
529 | struct vm_region *region, *last; |
530 | struct rb_node *p, *lastp; |
531 | |
532 | lastp = rb_first(&nommu_region_tree); |
533 | if (!lastp) |
534 | return; |
535 | |
536 | last = rb_entry(lastp, struct vm_region, vm_rb); |
537 | BUG_ON(unlikely(last->vm_end <= last->vm_start)); |
538 | BUG_ON(unlikely(last->vm_top < last->vm_end)); |
539 | |
540 | while ((p = rb_next(lastp))) { |
541 | region = rb_entry(p, struct vm_region, vm_rb); |
542 | last = rb_entry(lastp, struct vm_region, vm_rb); |
543 | |
544 | BUG_ON(unlikely(region->vm_end <= region->vm_start)); |
545 | BUG_ON(unlikely(region->vm_top < region->vm_end)); |
546 | BUG_ON(unlikely(region->vm_start < last->vm_top)); |
547 | |
548 | lastp = p; |
549 | } |
550 | } |
551 | #else |
552 | static void validate_nommu_regions(void) |
553 | { |
554 | } |
555 | #endif |
556 | |
557 | /* |
558 | * add a region into the global tree |
559 | */ |
560 | static void add_nommu_region(struct vm_region *region) |
561 | { |
562 | struct vm_region *pregion; |
563 | struct rb_node **p, *parent; |
564 | |
565 | validate_nommu_regions(); |
566 | |
567 | parent = NULL; |
568 | p = &nommu_region_tree.rb_node; |
569 | while (*p) { |
570 | parent = *p; |
571 | pregion = rb_entry(parent, struct vm_region, vm_rb); |
572 | if (region->vm_start < pregion->vm_start) |
573 | p = &(*p)->rb_left; |
574 | else if (region->vm_start > pregion->vm_start) |
575 | p = &(*p)->rb_right; |
576 | else if (pregion == region) |
577 | return; |
578 | else |
579 | BUG(); |
580 | } |
581 | |
582 | rb_link_node(®ion->vm_rb, parent, p); |
583 | rb_insert_color(®ion->vm_rb, &nommu_region_tree); |
584 | |
585 | validate_nommu_regions(); |
586 | } |
587 | |
588 | /* |
589 | * delete a region from the global tree |
590 | */ |
591 | static void delete_nommu_region(struct vm_region *region) |
592 | { |
593 | BUG_ON(!nommu_region_tree.rb_node); |
594 | |
595 | validate_nommu_regions(); |
596 | rb_erase(®ion->vm_rb, &nommu_region_tree); |
597 | validate_nommu_regions(); |
598 | } |
599 | |
600 | /* |
601 | * free a contiguous series of pages |
602 | */ |
603 | static void free_page_series(unsigned long from, unsigned long to) |
604 | { |
605 | for (; from < to; from += PAGE_SIZE) { |
606 | struct page *page = virt_to_page(from); |
607 | |
608 | kdebug("- free %lx", from); |
609 | atomic_long_dec(&mmap_pages_allocated); |
610 | if (page_count(page) != 1) |
611 | kdebug("free page %p: refcount not one: %d", |
612 | page, page_count(page)); |
613 | put_page(page); |
614 | } |
615 | } |
616 | |
617 | /* |
618 | * release a reference to a region |
619 | * - the caller must hold the region semaphore for writing, which this releases |
620 | * - the region may not have been added to the tree yet, in which case vm_top |
621 | * will equal vm_start |
622 | */ |
623 | static void __put_nommu_region(struct vm_region *region) |
624 | __releases(nommu_region_sem) |
625 | { |
626 | kenter("%p{%d}", region, region->vm_usage); |
627 | |
628 | BUG_ON(!nommu_region_tree.rb_node); |
629 | |
630 | if (--region->vm_usage == 0) { |
631 | if (region->vm_top > region->vm_start) |
632 | delete_nommu_region(region); |
633 | up_write(&nommu_region_sem); |
634 | |
635 | if (region->vm_file) |
636 | fput(region->vm_file); |
637 | |
638 | /* IO memory and memory shared directly out of the pagecache |
639 | * from ramfs/tmpfs mustn't be released here */ |
640 | if (region->vm_flags & VM_MAPPED_COPY) { |
641 | kdebug("free series"); |
642 | free_page_series(region->vm_start, region->vm_top); |
643 | } |
644 | kmem_cache_free(vm_region_jar, region); |
645 | } else { |
646 | up_write(&nommu_region_sem); |
647 | } |
648 | } |
649 | |
650 | /* |
651 | * release a reference to a region |
652 | */ |
653 | static void put_nommu_region(struct vm_region *region) |
654 | { |
655 | down_write(&nommu_region_sem); |
656 | __put_nommu_region(region); |
657 | } |
658 | |
659 | /* |
660 | * update protection on a vma |
661 | */ |
662 | static void protect_vma(struct vm_area_struct *vma, unsigned long flags) |
663 | { |
664 | #ifdef CONFIG_MPU |
665 | struct mm_struct *mm = vma->vm_mm; |
666 | long start = vma->vm_start & PAGE_MASK; |
667 | while (start < vma->vm_end) { |
668 | protect_page(mm, start, flags); |
669 | start += PAGE_SIZE; |
670 | } |
671 | update_protections(mm); |
672 | #endif |
673 | } |
674 | |
675 | /* |
676 | * add a VMA into a process's mm_struct in the appropriate place in the list |
677 | * and tree and add to the address space's page tree also if not an anonymous |
678 | * page |
679 | * - should be called with mm->mmap_sem held writelocked |
680 | */ |
681 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
682 | { |
683 | struct vm_area_struct *pvma, **pp, *next; |
684 | struct address_space *mapping; |
685 | struct rb_node **p, *parent; |
686 | |
687 | kenter(",%p", vma); |
688 | |
689 | BUG_ON(!vma->vm_region); |
690 | |
691 | mm->map_count++; |
692 | vma->vm_mm = mm; |
693 | |
694 | protect_vma(vma, vma->vm_flags); |
695 | |
696 | /* add the VMA to the mapping */ |
697 | if (vma->vm_file) { |
698 | mapping = vma->vm_file->f_mapping; |
699 | |
700 | flush_dcache_mmap_lock(mapping); |
701 | vma_prio_tree_insert(vma, &mapping->i_mmap); |
702 | flush_dcache_mmap_unlock(mapping); |
703 | } |
704 | |
705 | /* add the VMA to the tree */ |
706 | parent = NULL; |
707 | p = &mm->mm_rb.rb_node; |
708 | while (*p) { |
709 | parent = *p; |
710 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
711 | |
712 | /* sort by: start addr, end addr, VMA struct addr in that order |
713 | * (the latter is necessary as we may get identical VMAs) */ |
714 | if (vma->vm_start < pvma->vm_start) |
715 | p = &(*p)->rb_left; |
716 | else if (vma->vm_start > pvma->vm_start) |
717 | p = &(*p)->rb_right; |
718 | else if (vma->vm_end < pvma->vm_end) |
719 | p = &(*p)->rb_left; |
720 | else if (vma->vm_end > pvma->vm_end) |
721 | p = &(*p)->rb_right; |
722 | else if (vma < pvma) |
723 | p = &(*p)->rb_left; |
724 | else if (vma > pvma) |
725 | p = &(*p)->rb_right; |
726 | else |
727 | BUG(); |
728 | } |
729 | |
730 | rb_link_node(&vma->vm_rb, parent, p); |
731 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
732 | |
733 | /* add VMA to the VMA list also */ |
734 | for (pp = &mm->mmap; (pvma = *pp); pp = &(*pp)->vm_next) { |
735 | if (pvma->vm_start > vma->vm_start) |
736 | break; |
737 | if (pvma->vm_start < vma->vm_start) |
738 | continue; |
739 | if (pvma->vm_end < vma->vm_end) |
740 | break; |
741 | } |
742 | |
743 | next = *pp; |
744 | *pp = vma; |
745 | vma->vm_next = next; |
746 | if (next) |
747 | next->vm_prev = vma; |
748 | } |
749 | |
750 | /* |
751 | * delete a VMA from its owning mm_struct and address space |
752 | */ |
753 | static void delete_vma_from_mm(struct vm_area_struct *vma) |
754 | { |
755 | struct vm_area_struct **pp; |
756 | struct address_space *mapping; |
757 | struct mm_struct *mm = vma->vm_mm; |
758 | |
759 | kenter("%p", vma); |
760 | |
761 | protect_vma(vma, 0); |
762 | |
763 | mm->map_count--; |
764 | if (mm->mmap_cache == vma) |
765 | mm->mmap_cache = NULL; |
766 | |
767 | /* remove the VMA from the mapping */ |
768 | if (vma->vm_file) { |
769 | mapping = vma->vm_file->f_mapping; |
770 | |
771 | flush_dcache_mmap_lock(mapping); |
772 | vma_prio_tree_remove(vma, &mapping->i_mmap); |
773 | flush_dcache_mmap_unlock(mapping); |
774 | } |
775 | |
776 | /* remove from the MM's tree and list */ |
777 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
778 | for (pp = &mm->mmap; *pp; pp = &(*pp)->vm_next) { |
779 | if (*pp == vma) { |
780 | *pp = vma->vm_next; |
781 | break; |
782 | } |
783 | } |
784 | |
785 | vma->vm_mm = NULL; |
786 | } |
787 | |
788 | /* |
789 | * destroy a VMA record |
790 | */ |
791 | static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) |
792 | { |
793 | kenter("%p", vma); |
794 | if (vma->vm_ops && vma->vm_ops->close) |
795 | vma->vm_ops->close(vma); |
796 | if (vma->vm_file) { |
797 | fput(vma->vm_file); |
798 | if (vma->vm_flags & VM_EXECUTABLE) |
799 | removed_exe_file_vma(mm); |
800 | } |
801 | put_nommu_region(vma->vm_region); |
802 | kmem_cache_free(vm_area_cachep, vma); |
803 | } |
804 | |
805 | /* |
806 | * look up the first VMA in which addr resides, NULL if none |
807 | * - should be called with mm->mmap_sem at least held readlocked |
808 | */ |
809 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
810 | { |
811 | struct vm_area_struct *vma; |
812 | struct rb_node *n = mm->mm_rb.rb_node; |
813 | |
814 | /* check the cache first */ |
815 | vma = mm->mmap_cache; |
816 | if (vma && vma->vm_start <= addr && vma->vm_end > addr) |
817 | return vma; |
818 | |
819 | /* trawl the tree (there may be multiple mappings in which addr |
820 | * resides) */ |
821 | for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { |
822 | vma = rb_entry(n, struct vm_area_struct, vm_rb); |
823 | if (vma->vm_start > addr) |
824 | return NULL; |
825 | if (vma->vm_end > addr) { |
826 | mm->mmap_cache = vma; |
827 | return vma; |
828 | } |
829 | } |
830 | |
831 | return NULL; |
832 | } |
833 | EXPORT_SYMBOL(find_vma); |
834 | |
835 | /* |
836 | * find a VMA |
837 | * - we don't extend stack VMAs under NOMMU conditions |
838 | */ |
839 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) |
840 | { |
841 | return find_vma(mm, addr); |
842 | } |
843 | |
844 | /* |
845 | * expand a stack to a given address |
846 | * - not supported under NOMMU conditions |
847 | */ |
848 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
849 | { |
850 | return -ENOMEM; |
851 | } |
852 | |
853 | /* |
854 | * look up the first VMA exactly that exactly matches addr |
855 | * - should be called with mm->mmap_sem at least held readlocked |
856 | */ |
857 | static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, |
858 | unsigned long addr, |
859 | unsigned long len) |
860 | { |
861 | struct vm_area_struct *vma; |
862 | struct rb_node *n = mm->mm_rb.rb_node; |
863 | unsigned long end = addr + len; |
864 | |
865 | /* check the cache first */ |
866 | vma = mm->mmap_cache; |
867 | if (vma && vma->vm_start == addr && vma->vm_end == end) |
868 | return vma; |
869 | |
870 | /* trawl the tree (there may be multiple mappings in which addr |
871 | * resides) */ |
872 | for (n = rb_first(&mm->mm_rb); n; n = rb_next(n)) { |
873 | vma = rb_entry(n, struct vm_area_struct, vm_rb); |
874 | if (vma->vm_start < addr) |
875 | continue; |
876 | if (vma->vm_start > addr) |
877 | return NULL; |
878 | if (vma->vm_end == end) { |
879 | mm->mmap_cache = vma; |
880 | return vma; |
881 | } |
882 | } |
883 | |
884 | return NULL; |
885 | } |
886 | |
887 | /* |
888 | * determine whether a mapping should be permitted and, if so, what sort of |
889 | * mapping we're capable of supporting |
890 | */ |
891 | static int validate_mmap_request(struct file *file, |
892 | unsigned long addr, |
893 | unsigned long len, |
894 | unsigned long prot, |
895 | unsigned long flags, |
896 | unsigned long pgoff, |
897 | unsigned long *_capabilities) |
898 | { |
899 | unsigned long capabilities, rlen; |
900 | unsigned long reqprot = prot; |
901 | int ret; |
902 | |
903 | /* do the simple checks first */ |
904 | if (flags & MAP_FIXED) { |
905 | printk(KERN_DEBUG |
906 | "%d: Can't do fixed-address/overlay mmap of RAM\n", |
907 | current->pid); |
908 | return -EINVAL; |
909 | } |
910 | |
911 | if ((flags & MAP_TYPE) != MAP_PRIVATE && |
912 | (flags & MAP_TYPE) != MAP_SHARED) |
913 | return -EINVAL; |
914 | |
915 | if (!len) |
916 | return -EINVAL; |
917 | |
918 | /* Careful about overflows.. */ |
919 | rlen = PAGE_ALIGN(len); |
920 | if (!rlen || rlen > TASK_SIZE) |
921 | return -ENOMEM; |
922 | |
923 | /* offset overflow? */ |
924 | if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
925 | return -EOVERFLOW; |
926 | |
927 | if (file) { |
928 | /* validate file mapping requests */ |
929 | struct address_space *mapping; |
930 | |
931 | /* files must support mmap */ |
932 | if (!file->f_op || !file->f_op->mmap) |
933 | return -ENODEV; |
934 | |
935 | /* work out if what we've got could possibly be shared |
936 | * - we support chardevs that provide their own "memory" |
937 | * - we support files/blockdevs that are memory backed |
938 | */ |
939 | mapping = file->f_mapping; |
940 | if (!mapping) |
941 | mapping = file->f_path.dentry->d_inode->i_mapping; |
942 | |
943 | capabilities = 0; |
944 | if (mapping && mapping->backing_dev_info) |
945 | capabilities = mapping->backing_dev_info->capabilities; |
946 | |
947 | if (!capabilities) { |
948 | /* no explicit capabilities set, so assume some |
949 | * defaults */ |
950 | switch (file->f_path.dentry->d_inode->i_mode & S_IFMT) { |
951 | case S_IFREG: |
952 | case S_IFBLK: |
953 | capabilities = BDI_CAP_MAP_COPY; |
954 | break; |
955 | |
956 | case S_IFCHR: |
957 | capabilities = |
958 | BDI_CAP_MAP_DIRECT | |
959 | BDI_CAP_READ_MAP | |
960 | BDI_CAP_WRITE_MAP; |
961 | break; |
962 | |
963 | default: |
964 | return -EINVAL; |
965 | } |
966 | } |
967 | |
968 | /* eliminate any capabilities that we can't support on this |
969 | * device */ |
970 | if (!file->f_op->get_unmapped_area) |
971 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
972 | if (!file->f_op->read) |
973 | capabilities &= ~BDI_CAP_MAP_COPY; |
974 | |
975 | /* The file shall have been opened with read permission. */ |
976 | if (!(file->f_mode & FMODE_READ)) |
977 | return -EACCES; |
978 | |
979 | if (flags & MAP_SHARED) { |
980 | /* do checks for writing, appending and locking */ |
981 | if ((prot & PROT_WRITE) && |
982 | !(file->f_mode & FMODE_WRITE)) |
983 | return -EACCES; |
984 | |
985 | if (IS_APPEND(file->f_path.dentry->d_inode) && |
986 | (file->f_mode & FMODE_WRITE)) |
987 | return -EACCES; |
988 | |
989 | if (locks_verify_locked(file->f_path.dentry->d_inode)) |
990 | return -EAGAIN; |
991 | |
992 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
993 | return -ENODEV; |
994 | |
995 | /* we mustn't privatise shared mappings */ |
996 | capabilities &= ~BDI_CAP_MAP_COPY; |
997 | } |
998 | else { |
999 | /* we're going to read the file into private memory we |
1000 | * allocate */ |
1001 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
1002 | return -ENODEV; |
1003 | |
1004 | /* we don't permit a private writable mapping to be |
1005 | * shared with the backing device */ |
1006 | if (prot & PROT_WRITE) |
1007 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1008 | } |
1009 | |
1010 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1011 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || |
1012 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || |
1013 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) |
1014 | ) { |
1015 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1016 | if (flags & MAP_SHARED) { |
1017 | printk(KERN_WARNING |
1018 | "MAP_SHARED not completely supported on !MMU\n"); |
1019 | return -EINVAL; |
1020 | } |
1021 | } |
1022 | } |
1023 | |
1024 | /* handle executable mappings and implied executable |
1025 | * mappings */ |
1026 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1027 | if (prot & PROT_EXEC) |
1028 | return -EPERM; |
1029 | } |
1030 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { |
1031 | /* handle implication of PROT_EXEC by PROT_READ */ |
1032 | if (current->personality & READ_IMPLIES_EXEC) { |
1033 | if (capabilities & BDI_CAP_EXEC_MAP) |
1034 | prot |= PROT_EXEC; |
1035 | } |
1036 | } |
1037 | else if ((prot & PROT_READ) && |
1038 | (prot & PROT_EXEC) && |
1039 | !(capabilities & BDI_CAP_EXEC_MAP) |
1040 | ) { |
1041 | /* backing file is not executable, try to copy */ |
1042 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1043 | } |
1044 | } |
1045 | else { |
1046 | /* anonymous mappings are always memory backed and can be |
1047 | * privately mapped |
1048 | */ |
1049 | capabilities = BDI_CAP_MAP_COPY; |
1050 | |
1051 | /* handle PROT_EXEC implication by PROT_READ */ |
1052 | if ((prot & PROT_READ) && |
1053 | (current->personality & READ_IMPLIES_EXEC)) |
1054 | prot |= PROT_EXEC; |
1055 | } |
1056 | |
1057 | /* allow the security API to have its say */ |
1058 | ret = security_file_mmap(file, reqprot, prot, flags, addr, 0); |
1059 | if (ret < 0) |
1060 | return ret; |
1061 | |
1062 | /* looks okay */ |
1063 | *_capabilities = capabilities; |
1064 | return 0; |
1065 | } |
1066 | |
1067 | /* |
1068 | * we've determined that we can make the mapping, now translate what we |
1069 | * now know into VMA flags |
1070 | */ |
1071 | static unsigned long determine_vm_flags(struct file *file, |
1072 | unsigned long prot, |
1073 | unsigned long flags, |
1074 | unsigned long capabilities) |
1075 | { |
1076 | unsigned long vm_flags; |
1077 | |
1078 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); |
1079 | /* vm_flags |= mm->def_flags; */ |
1080 | |
1081 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { |
1082 | /* attempt to share read-only copies of mapped file chunks */ |
1083 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
1084 | if (file && !(prot & PROT_WRITE)) |
1085 | vm_flags |= VM_MAYSHARE; |
1086 | } else { |
1087 | /* overlay a shareable mapping on the backing device or inode |
1088 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and |
1089 | * romfs/cramfs */ |
1090 | vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS); |
1091 | if (flags & MAP_SHARED) |
1092 | vm_flags |= VM_SHARED; |
1093 | } |
1094 | |
1095 | /* refuse to let anyone share private mappings with this process if |
1096 | * it's being traced - otherwise breakpoints set in it may interfere |
1097 | * with another untraced process |
1098 | */ |
1099 | if ((flags & MAP_PRIVATE) && tracehook_expect_breakpoints(current)) |
1100 | vm_flags &= ~VM_MAYSHARE; |
1101 | |
1102 | return vm_flags; |
1103 | } |
1104 | |
1105 | /* |
1106 | * set up a shared mapping on a file (the driver or filesystem provides and |
1107 | * pins the storage) |
1108 | */ |
1109 | static int do_mmap_shared_file(struct vm_area_struct *vma) |
1110 | { |
1111 | int ret; |
1112 | |
1113 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
1114 | if (ret == 0) { |
1115 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
1116 | return 0; |
1117 | } |
1118 | if (ret != -ENOSYS) |
1119 | return ret; |
1120 | |
1121 | /* getting -ENOSYS indicates that direct mmap isn't possible (as |
1122 | * opposed to tried but failed) so we can only give a suitable error as |
1123 | * it's not possible to make a private copy if MAP_SHARED was given */ |
1124 | return -ENODEV; |
1125 | } |
1126 | |
1127 | /* |
1128 | * set up a private mapping or an anonymous shared mapping |
1129 | */ |
1130 | static int do_mmap_private(struct vm_area_struct *vma, |
1131 | struct vm_region *region, |
1132 | unsigned long len, |
1133 | unsigned long capabilities) |
1134 | { |
1135 | struct page *pages; |
1136 | unsigned long total, point, n, rlen; |
1137 | void *base; |
1138 | int ret, order; |
1139 | |
1140 | /* invoke the file's mapping function so that it can keep track of |
1141 | * shared mappings on devices or memory |
1142 | * - VM_MAYSHARE will be set if it may attempt to share |
1143 | */ |
1144 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1145 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
1146 | if (ret == 0) { |
1147 | /* shouldn't return success if we're not sharing */ |
1148 | BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
1149 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
1150 | return 0; |
1151 | } |
1152 | if (ret != -ENOSYS) |
1153 | return ret; |
1154 | |
1155 | /* getting an ENOSYS error indicates that direct mmap isn't |
1156 | * possible (as opposed to tried but failed) so we'll try to |
1157 | * make a private copy of the data and map that instead */ |
1158 | } |
1159 | |
1160 | rlen = PAGE_ALIGN(len); |
1161 | |
1162 | /* allocate some memory to hold the mapping |
1163 | * - note that this may not return a page-aligned address if the object |
1164 | * we're allocating is smaller than a page |
1165 | */ |
1166 | order = get_order(rlen); |
1167 | kdebug("alloc order %d for %lx", order, len); |
1168 | |
1169 | pages = alloc_pages(GFP_KERNEL, order); |
1170 | if (!pages) |
1171 | goto enomem; |
1172 | |
1173 | total = 1 << order; |
1174 | atomic_long_add(total, &mmap_pages_allocated); |
1175 | |
1176 | point = rlen >> PAGE_SHIFT; |
1177 | |
1178 | /* we allocated a power-of-2 sized page set, so we may want to trim off |
1179 | * the excess */ |
1180 | if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) { |
1181 | while (total > point) { |
1182 | order = ilog2(total - point); |
1183 | n = 1 << order; |
1184 | kdebug("shave %lu/%lu @%lu", n, total - point, total); |
1185 | atomic_long_sub(n, &mmap_pages_allocated); |
1186 | total -= n; |
1187 | set_page_refcounted(pages + total); |
1188 | __free_pages(pages + total, order); |
1189 | } |
1190 | } |
1191 | |
1192 | for (point = 1; point < total; point++) |
1193 | set_page_refcounted(&pages[point]); |
1194 | |
1195 | base = page_address(pages); |
1196 | region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; |
1197 | region->vm_start = (unsigned long) base; |
1198 | region->vm_end = region->vm_start + rlen; |
1199 | region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
1200 | |
1201 | vma->vm_start = region->vm_start; |
1202 | vma->vm_end = region->vm_start + len; |
1203 | |
1204 | if (vma->vm_file) { |
1205 | /* read the contents of a file into the copy */ |
1206 | mm_segment_t old_fs; |
1207 | loff_t fpos; |
1208 | |
1209 | fpos = vma->vm_pgoff; |
1210 | fpos <<= PAGE_SHIFT; |
1211 | |
1212 | old_fs = get_fs(); |
1213 | set_fs(KERNEL_DS); |
1214 | ret = vma->vm_file->f_op->read(vma->vm_file, base, rlen, &fpos); |
1215 | set_fs(old_fs); |
1216 | |
1217 | if (ret < 0) |
1218 | goto error_free; |
1219 | |
1220 | /* clear the last little bit */ |
1221 | if (ret < rlen) |
1222 | memset(base + ret, 0, rlen - ret); |
1223 | |
1224 | } |
1225 | |
1226 | return 0; |
1227 | |
1228 | error_free: |
1229 | free_page_series(region->vm_start, region->vm_end); |
1230 | region->vm_start = vma->vm_start = 0; |
1231 | region->vm_end = vma->vm_end = 0; |
1232 | region->vm_top = 0; |
1233 | return ret; |
1234 | |
1235 | enomem: |
1236 | printk("Allocation of length %lu from process %d (%s) failed\n", |
1237 | len, current->pid, current->comm); |
1238 | show_free_areas(); |
1239 | return -ENOMEM; |
1240 | } |
1241 | |
1242 | /* |
1243 | * handle mapping creation for uClinux |
1244 | */ |
1245 | unsigned long do_mmap_pgoff(struct file *file, |
1246 | unsigned long addr, |
1247 | unsigned long len, |
1248 | unsigned long prot, |
1249 | unsigned long flags, |
1250 | unsigned long pgoff) |
1251 | { |
1252 | struct vm_area_struct *vma; |
1253 | struct vm_region *region; |
1254 | struct rb_node *rb; |
1255 | unsigned long capabilities, vm_flags, result; |
1256 | int ret; |
1257 | |
1258 | kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); |
1259 | |
1260 | /* decide whether we should attempt the mapping, and if so what sort of |
1261 | * mapping */ |
1262 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, |
1263 | &capabilities); |
1264 | if (ret < 0) { |
1265 | kleave(" = %d [val]", ret); |
1266 | return ret; |
1267 | } |
1268 | |
1269 | /* we ignore the address hint */ |
1270 | addr = 0; |
1271 | |
1272 | /* we've determined that we can make the mapping, now translate what we |
1273 | * now know into VMA flags */ |
1274 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); |
1275 | |
1276 | /* we're going to need to record the mapping */ |
1277 | region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); |
1278 | if (!region) |
1279 | goto error_getting_region; |
1280 | |
1281 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1282 | if (!vma) |
1283 | goto error_getting_vma; |
1284 | |
1285 | region->vm_usage = 1; |
1286 | region->vm_flags = vm_flags; |
1287 | region->vm_pgoff = pgoff; |
1288 | |
1289 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1290 | vma->vm_flags = vm_flags; |
1291 | vma->vm_pgoff = pgoff; |
1292 | |
1293 | if (file) { |
1294 | region->vm_file = file; |
1295 | get_file(file); |
1296 | vma->vm_file = file; |
1297 | get_file(file); |
1298 | if (vm_flags & VM_EXECUTABLE) { |
1299 | added_exe_file_vma(current->mm); |
1300 | vma->vm_mm = current->mm; |
1301 | } |
1302 | } |
1303 | |
1304 | down_write(&nommu_region_sem); |
1305 | |
1306 | /* if we want to share, we need to check for regions created by other |
1307 | * mmap() calls that overlap with our proposed mapping |
1308 | * - we can only share with a superset match on most regular files |
1309 | * - shared mappings on character devices and memory backed files are |
1310 | * permitted to overlap inexactly as far as we are concerned for in |
1311 | * these cases, sharing is handled in the driver or filesystem rather |
1312 | * than here |
1313 | */ |
1314 | if (vm_flags & VM_MAYSHARE) { |
1315 | struct vm_region *pregion; |
1316 | unsigned long pglen, rpglen, pgend, rpgend, start; |
1317 | |
1318 | pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1319 | pgend = pgoff + pglen; |
1320 | |
1321 | for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
1322 | pregion = rb_entry(rb, struct vm_region, vm_rb); |
1323 | |
1324 | if (!(pregion->vm_flags & VM_MAYSHARE)) |
1325 | continue; |
1326 | |
1327 | /* search for overlapping mappings on the same file */ |
1328 | if (pregion->vm_file->f_path.dentry->d_inode != |
1329 | file->f_path.dentry->d_inode) |
1330 | continue; |
1331 | |
1332 | if (pregion->vm_pgoff >= pgend) |
1333 | continue; |
1334 | |
1335 | rpglen = pregion->vm_end - pregion->vm_start; |
1336 | rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1337 | rpgend = pregion->vm_pgoff + rpglen; |
1338 | if (pgoff >= rpgend) |
1339 | continue; |
1340 | |
1341 | /* handle inexactly overlapping matches between |
1342 | * mappings */ |
1343 | if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && |
1344 | !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { |
1345 | /* new mapping is not a subset of the region */ |
1346 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
1347 | goto sharing_violation; |
1348 | continue; |
1349 | } |
1350 | |
1351 | /* we've found a region we can share */ |
1352 | pregion->vm_usage++; |
1353 | vma->vm_region = pregion; |
1354 | start = pregion->vm_start; |
1355 | start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; |
1356 | vma->vm_start = start; |
1357 | vma->vm_end = start + len; |
1358 | |
1359 | if (pregion->vm_flags & VM_MAPPED_COPY) { |
1360 | kdebug("share copy"); |
1361 | vma->vm_flags |= VM_MAPPED_COPY; |
1362 | } else { |
1363 | kdebug("share mmap"); |
1364 | ret = do_mmap_shared_file(vma); |
1365 | if (ret < 0) { |
1366 | vma->vm_region = NULL; |
1367 | vma->vm_start = 0; |
1368 | vma->vm_end = 0; |
1369 | pregion->vm_usage--; |
1370 | pregion = NULL; |
1371 | goto error_just_free; |
1372 | } |
1373 | } |
1374 | fput(region->vm_file); |
1375 | kmem_cache_free(vm_region_jar, region); |
1376 | region = pregion; |
1377 | result = start; |
1378 | goto share; |
1379 | } |
1380 | |
1381 | /* obtain the address at which to make a shared mapping |
1382 | * - this is the hook for quasi-memory character devices to |
1383 | * tell us the location of a shared mapping |
1384 | */ |
1385 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1386 | addr = file->f_op->get_unmapped_area(file, addr, len, |
1387 | pgoff, flags); |
1388 | if (IS_ERR((void *) addr)) { |
1389 | ret = addr; |
1390 | if (ret != (unsigned long) -ENOSYS) |
1391 | goto error_just_free; |
1392 | |
1393 | /* the driver refused to tell us where to site |
1394 | * the mapping so we'll have to attempt to copy |
1395 | * it */ |
1396 | ret = (unsigned long) -ENODEV; |
1397 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
1398 | goto error_just_free; |
1399 | |
1400 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1401 | } else { |
1402 | vma->vm_start = region->vm_start = addr; |
1403 | vma->vm_end = region->vm_end = addr + len; |
1404 | } |
1405 | } |
1406 | } |
1407 | |
1408 | vma->vm_region = region; |
1409 | |
1410 | /* set up the mapping |
1411 | * - the region is filled in if BDI_CAP_MAP_DIRECT is still set |
1412 | */ |
1413 | if (file && vma->vm_flags & VM_SHARED) |
1414 | ret = do_mmap_shared_file(vma); |
1415 | else |
1416 | ret = do_mmap_private(vma, region, len, capabilities); |
1417 | if (ret < 0) |
1418 | goto error_just_free; |
1419 | add_nommu_region(region); |
1420 | |
1421 | /* clear anonymous mappings that don't ask for uninitialized data */ |
1422 | if (!vma->vm_file && !(flags & MAP_UNINITIALIZED)) |
1423 | memset((void *)region->vm_start, 0, |
1424 | region->vm_end - region->vm_start); |
1425 | |
1426 | /* okay... we have a mapping; now we have to register it */ |
1427 | result = vma->vm_start; |
1428 | |
1429 | current->mm->total_vm += len >> PAGE_SHIFT; |
1430 | |
1431 | share: |
1432 | add_vma_to_mm(current->mm, vma); |
1433 | |
1434 | /* we flush the region from the icache only when the first executable |
1435 | * mapping of it is made */ |
1436 | if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { |
1437 | flush_icache_range(region->vm_start, region->vm_end); |
1438 | region->vm_icache_flushed = true; |
1439 | } |
1440 | |
1441 | up_write(&nommu_region_sem); |
1442 | |
1443 | kleave(" = %lx", result); |
1444 | return result; |
1445 | |
1446 | error_just_free: |
1447 | up_write(&nommu_region_sem); |
1448 | error: |
1449 | if (region->vm_file) |
1450 | fput(region->vm_file); |
1451 | kmem_cache_free(vm_region_jar, region); |
1452 | if (vma->vm_file) |
1453 | fput(vma->vm_file); |
1454 | if (vma->vm_flags & VM_EXECUTABLE) |
1455 | removed_exe_file_vma(vma->vm_mm); |
1456 | kmem_cache_free(vm_area_cachep, vma); |
1457 | kleave(" = %d", ret); |
1458 | return ret; |
1459 | |
1460 | sharing_violation: |
1461 | up_write(&nommu_region_sem); |
1462 | printk(KERN_WARNING "Attempt to share mismatched mappings\n"); |
1463 | ret = -EINVAL; |
1464 | goto error; |
1465 | |
1466 | error_getting_vma: |
1467 | kmem_cache_free(vm_region_jar, region); |
1468 | printk(KERN_WARNING "Allocation of vma for %lu byte allocation" |
1469 | " from process %d failed\n", |
1470 | len, current->pid); |
1471 | show_free_areas(); |
1472 | return -ENOMEM; |
1473 | |
1474 | error_getting_region: |
1475 | printk(KERN_WARNING "Allocation of vm region for %lu byte allocation" |
1476 | " from process %d failed\n", |
1477 | len, current->pid); |
1478 | show_free_areas(); |
1479 | return -ENOMEM; |
1480 | } |
1481 | EXPORT_SYMBOL(do_mmap_pgoff); |
1482 | |
1483 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1484 | unsigned long, prot, unsigned long, flags, |
1485 | unsigned long, fd, unsigned long, pgoff) |
1486 | { |
1487 | struct file *file = NULL; |
1488 | unsigned long retval = -EBADF; |
1489 | |
1490 | audit_mmap_fd(fd, flags); |
1491 | if (!(flags & MAP_ANONYMOUS)) { |
1492 | file = fget(fd); |
1493 | if (!file) |
1494 | goto out; |
1495 | } |
1496 | |
1497 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); |
1498 | |
1499 | down_write(¤t->mm->mmap_sem); |
1500 | retval = do_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
1501 | up_write(¤t->mm->mmap_sem); |
1502 | |
1503 | if (file) |
1504 | fput(file); |
1505 | out: |
1506 | return retval; |
1507 | } |
1508 | |
1509 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1510 | struct mmap_arg_struct { |
1511 | unsigned long addr; |
1512 | unsigned long len; |
1513 | unsigned long prot; |
1514 | unsigned long flags; |
1515 | unsigned long fd; |
1516 | unsigned long offset; |
1517 | }; |
1518 | |
1519 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) |
1520 | { |
1521 | struct mmap_arg_struct a; |
1522 | |
1523 | if (copy_from_user(&a, arg, sizeof(a))) |
1524 | return -EFAULT; |
1525 | if (a.offset & ~PAGE_MASK) |
1526 | return -EINVAL; |
1527 | |
1528 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
1529 | a.offset >> PAGE_SHIFT); |
1530 | } |
1531 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
1532 | |
1533 | /* |
1534 | * split a vma into two pieces at address 'addr', a new vma is allocated either |
1535 | * for the first part or the tail. |
1536 | */ |
1537 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
1538 | unsigned long addr, int new_below) |
1539 | { |
1540 | struct vm_area_struct *new; |
1541 | struct vm_region *region; |
1542 | unsigned long npages; |
1543 | |
1544 | kenter(""); |
1545 | |
1546 | /* we're only permitted to split anonymous regions (these should have |
1547 | * only a single usage on the region) */ |
1548 | if (vma->vm_file) |
1549 | return -ENOMEM; |
1550 | |
1551 | if (mm->map_count >= sysctl_max_map_count) |
1552 | return -ENOMEM; |
1553 | |
1554 | region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
1555 | if (!region) |
1556 | return -ENOMEM; |
1557 | |
1558 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1559 | if (!new) { |
1560 | kmem_cache_free(vm_region_jar, region); |
1561 | return -ENOMEM; |
1562 | } |
1563 | |
1564 | /* most fields are the same, copy all, and then fixup */ |
1565 | *new = *vma; |
1566 | *region = *vma->vm_region; |
1567 | new->vm_region = region; |
1568 | |
1569 | npages = (addr - vma->vm_start) >> PAGE_SHIFT; |
1570 | |
1571 | if (new_below) { |
1572 | region->vm_top = region->vm_end = new->vm_end = addr; |
1573 | } else { |
1574 | region->vm_start = new->vm_start = addr; |
1575 | region->vm_pgoff = new->vm_pgoff += npages; |
1576 | } |
1577 | |
1578 | if (new->vm_ops && new->vm_ops->open) |
1579 | new->vm_ops->open(new); |
1580 | |
1581 | delete_vma_from_mm(vma); |
1582 | down_write(&nommu_region_sem); |
1583 | delete_nommu_region(vma->vm_region); |
1584 | if (new_below) { |
1585 | vma->vm_region->vm_start = vma->vm_start = addr; |
1586 | vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; |
1587 | } else { |
1588 | vma->vm_region->vm_end = vma->vm_end = addr; |
1589 | vma->vm_region->vm_top = addr; |
1590 | } |
1591 | add_nommu_region(vma->vm_region); |
1592 | add_nommu_region(new->vm_region); |
1593 | up_write(&nommu_region_sem); |
1594 | add_vma_to_mm(mm, vma); |
1595 | add_vma_to_mm(mm, new); |
1596 | return 0; |
1597 | } |
1598 | |
1599 | /* |
1600 | * shrink a VMA by removing the specified chunk from either the beginning or |
1601 | * the end |
1602 | */ |
1603 | static int shrink_vma(struct mm_struct *mm, |
1604 | struct vm_area_struct *vma, |
1605 | unsigned long from, unsigned long to) |
1606 | { |
1607 | struct vm_region *region; |
1608 | |
1609 | kenter(""); |
1610 | |
1611 | /* adjust the VMA's pointers, which may reposition it in the MM's tree |
1612 | * and list */ |
1613 | delete_vma_from_mm(vma); |
1614 | if (from > vma->vm_start) |
1615 | vma->vm_end = from; |
1616 | else |
1617 | vma->vm_start = to; |
1618 | add_vma_to_mm(mm, vma); |
1619 | |
1620 | /* cut the backing region down to size */ |
1621 | region = vma->vm_region; |
1622 | BUG_ON(region->vm_usage != 1); |
1623 | |
1624 | down_write(&nommu_region_sem); |
1625 | delete_nommu_region(region); |
1626 | if (from > region->vm_start) { |
1627 | to = region->vm_top; |
1628 | region->vm_top = region->vm_end = from; |
1629 | } else { |
1630 | region->vm_start = to; |
1631 | } |
1632 | add_nommu_region(region); |
1633 | up_write(&nommu_region_sem); |
1634 | |
1635 | free_page_series(from, to); |
1636 | return 0; |
1637 | } |
1638 | |
1639 | /* |
1640 | * release a mapping |
1641 | * - under NOMMU conditions the chunk to be unmapped must be backed by a single |
1642 | * VMA, though it need not cover the whole VMA |
1643 | */ |
1644 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
1645 | { |
1646 | struct vm_area_struct *vma; |
1647 | struct rb_node *rb; |
1648 | unsigned long end = start + len; |
1649 | int ret; |
1650 | |
1651 | kenter(",%lx,%zx", start, len); |
1652 | |
1653 | if (len == 0) |
1654 | return -EINVAL; |
1655 | |
1656 | /* find the first potentially overlapping VMA */ |
1657 | vma = find_vma(mm, start); |
1658 | if (!vma) { |
1659 | static int limit = 0; |
1660 | if (limit < 5) { |
1661 | printk(KERN_WARNING |
1662 | "munmap of memory not mmapped by process %d" |
1663 | " (%s): 0x%lx-0x%lx\n", |
1664 | current->pid, current->comm, |
1665 | start, start + len - 1); |
1666 | limit++; |
1667 | } |
1668 | return -EINVAL; |
1669 | } |
1670 | |
1671 | /* we're allowed to split an anonymous VMA but not a file-backed one */ |
1672 | if (vma->vm_file) { |
1673 | do { |
1674 | if (start > vma->vm_start) { |
1675 | kleave(" = -EINVAL [miss]"); |
1676 | return -EINVAL; |
1677 | } |
1678 | if (end == vma->vm_end) |
1679 | goto erase_whole_vma; |
1680 | rb = rb_next(&vma->vm_rb); |
1681 | vma = rb_entry(rb, struct vm_area_struct, vm_rb); |
1682 | } while (rb); |
1683 | kleave(" = -EINVAL [split file]"); |
1684 | return -EINVAL; |
1685 | } else { |
1686 | /* the chunk must be a subset of the VMA found */ |
1687 | if (start == vma->vm_start && end == vma->vm_end) |
1688 | goto erase_whole_vma; |
1689 | if (start < vma->vm_start || end > vma->vm_end) { |
1690 | kleave(" = -EINVAL [superset]"); |
1691 | return -EINVAL; |
1692 | } |
1693 | if (start & ~PAGE_MASK) { |
1694 | kleave(" = -EINVAL [unaligned start]"); |
1695 | return -EINVAL; |
1696 | } |
1697 | if (end != vma->vm_end && end & ~PAGE_MASK) { |
1698 | kleave(" = -EINVAL [unaligned split]"); |
1699 | return -EINVAL; |
1700 | } |
1701 | if (start != vma->vm_start && end != vma->vm_end) { |
1702 | ret = split_vma(mm, vma, start, 1); |
1703 | if (ret < 0) { |
1704 | kleave(" = %d [split]", ret); |
1705 | return ret; |
1706 | } |
1707 | } |
1708 | return shrink_vma(mm, vma, start, end); |
1709 | } |
1710 | |
1711 | erase_whole_vma: |
1712 | delete_vma_from_mm(vma); |
1713 | delete_vma(mm, vma); |
1714 | kleave(" = 0"); |
1715 | return 0; |
1716 | } |
1717 | EXPORT_SYMBOL(do_munmap); |
1718 | |
1719 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
1720 | { |
1721 | int ret; |
1722 | struct mm_struct *mm = current->mm; |
1723 | |
1724 | down_write(&mm->mmap_sem); |
1725 | ret = do_munmap(mm, addr, len); |
1726 | up_write(&mm->mmap_sem); |
1727 | return ret; |
1728 | } |
1729 | |
1730 | /* |
1731 | * release all the mappings made in a process's VM space |
1732 | */ |
1733 | void exit_mmap(struct mm_struct *mm) |
1734 | { |
1735 | struct vm_area_struct *vma; |
1736 | |
1737 | if (!mm) |
1738 | return; |
1739 | |
1740 | kenter(""); |
1741 | |
1742 | mm->total_vm = 0; |
1743 | |
1744 | while ((vma = mm->mmap)) { |
1745 | mm->mmap = vma->vm_next; |
1746 | delete_vma_from_mm(vma); |
1747 | delete_vma(mm, vma); |
1748 | cond_resched(); |
1749 | } |
1750 | |
1751 | kleave(""); |
1752 | } |
1753 | |
1754 | unsigned long do_brk(unsigned long addr, unsigned long len) |
1755 | { |
1756 | return -ENOMEM; |
1757 | } |
1758 | |
1759 | /* |
1760 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1761 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
1762 | * |
1763 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
1764 | * as long as it stays within the region allocated by do_mmap_private() and the |
1765 | * block is not shareable |
1766 | * |
1767 | * MREMAP_FIXED is not supported under NOMMU conditions |
1768 | */ |
1769 | unsigned long do_mremap(unsigned long addr, |
1770 | unsigned long old_len, unsigned long new_len, |
1771 | unsigned long flags, unsigned long new_addr) |
1772 | { |
1773 | struct vm_area_struct *vma; |
1774 | |
1775 | /* insanity checks first */ |
1776 | if (old_len == 0 || new_len == 0) |
1777 | return (unsigned long) -EINVAL; |
1778 | |
1779 | if (addr & ~PAGE_MASK) |
1780 | return -EINVAL; |
1781 | |
1782 | if (flags & MREMAP_FIXED && new_addr != addr) |
1783 | return (unsigned long) -EINVAL; |
1784 | |
1785 | vma = find_vma_exact(current->mm, addr, old_len); |
1786 | if (!vma) |
1787 | return (unsigned long) -EINVAL; |
1788 | |
1789 | if (vma->vm_end != vma->vm_start + old_len) |
1790 | return (unsigned long) -EFAULT; |
1791 | |
1792 | if (vma->vm_flags & VM_MAYSHARE) |
1793 | return (unsigned long) -EPERM; |
1794 | |
1795 | if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1796 | return (unsigned long) -ENOMEM; |
1797 | |
1798 | /* all checks complete - do it */ |
1799 | vma->vm_end = vma->vm_start + new_len; |
1800 | return vma->vm_start; |
1801 | } |
1802 | EXPORT_SYMBOL(do_mremap); |
1803 | |
1804 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
1805 | unsigned long, new_len, unsigned long, flags, |
1806 | unsigned long, new_addr) |
1807 | { |
1808 | unsigned long ret; |
1809 | |
1810 | down_write(¤t->mm->mmap_sem); |
1811 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
1812 | up_write(¤t->mm->mmap_sem); |
1813 | return ret; |
1814 | } |
1815 | |
1816 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
1817 | unsigned int foll_flags) |
1818 | { |
1819 | return NULL; |
1820 | } |
1821 | |
1822 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, |
1823 | unsigned long to, unsigned long size, pgprot_t prot) |
1824 | { |
1825 | vma->vm_start = vma->vm_pgoff << PAGE_SHIFT; |
1826 | return 0; |
1827 | } |
1828 | EXPORT_SYMBOL(remap_pfn_range); |
1829 | |
1830 | int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
1831 | unsigned long pgoff) |
1832 | { |
1833 | unsigned int size = vma->vm_end - vma->vm_start; |
1834 | |
1835 | if (!(vma->vm_flags & VM_USERMAP)) |
1836 | return -EINVAL; |
1837 | |
1838 | vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); |
1839 | vma->vm_end = vma->vm_start + size; |
1840 | |
1841 | return 0; |
1842 | } |
1843 | EXPORT_SYMBOL(remap_vmalloc_range); |
1844 | |
1845 | void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page) |
1846 | { |
1847 | } |
1848 | |
1849 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, |
1850 | unsigned long len, unsigned long pgoff, unsigned long flags) |
1851 | { |
1852 | return -ENOMEM; |
1853 | } |
1854 | |
1855 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1856 | { |
1857 | } |
1858 | |
1859 | void unmap_mapping_range(struct address_space *mapping, |
1860 | loff_t const holebegin, loff_t const holelen, |
1861 | int even_cows) |
1862 | { |
1863 | } |
1864 | EXPORT_SYMBOL(unmap_mapping_range); |
1865 | |
1866 | /* |
1867 | * Check that a process has enough memory to allocate a new virtual |
1868 | * mapping. 0 means there is enough memory for the allocation to |
1869 | * succeed and -ENOMEM implies there is not. |
1870 | * |
1871 | * We currently support three overcommit policies, which are set via the |
1872 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
1873 | * |
1874 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
1875 | * Additional code 2002 Jul 20 by Robert Love. |
1876 | * |
1877 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
1878 | * |
1879 | * Note this is a helper function intended to be used by LSMs which |
1880 | * wish to use this logic. |
1881 | */ |
1882 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1883 | { |
1884 | unsigned long free, allowed; |
1885 | |
1886 | vm_acct_memory(pages); |
1887 | |
1888 | /* |
1889 | * Sometimes we want to use more memory than we have |
1890 | */ |
1891 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
1892 | return 0; |
1893 | |
1894 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
1895 | unsigned long n; |
1896 | |
1897 | free = global_page_state(NR_FILE_PAGES); |
1898 | free += nr_swap_pages; |
1899 | |
1900 | /* |
1901 | * Any slabs which are created with the |
1902 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
1903 | * which are reclaimable, under pressure. The dentry |
1904 | * cache and most inode caches should fall into this |
1905 | */ |
1906 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1907 | |
1908 | /* |
1909 | * Leave the last 3% for root |
1910 | */ |
1911 | if (!cap_sys_admin) |
1912 | free -= free / 32; |
1913 | |
1914 | if (free > pages) |
1915 | return 0; |
1916 | |
1917 | /* |
1918 | * nr_free_pages() is very expensive on large systems, |
1919 | * only call if we're about to fail. |
1920 | */ |
1921 | n = nr_free_pages(); |
1922 | |
1923 | /* |
1924 | * Leave reserved pages. The pages are not for anonymous pages. |
1925 | */ |
1926 | if (n <= totalreserve_pages) |
1927 | goto error; |
1928 | else |
1929 | n -= totalreserve_pages; |
1930 | |
1931 | /* |
1932 | * Leave the last 3% for root |
1933 | */ |
1934 | if (!cap_sys_admin) |
1935 | n -= n / 32; |
1936 | free += n; |
1937 | |
1938 | if (free > pages) |
1939 | return 0; |
1940 | |
1941 | goto error; |
1942 | } |
1943 | |
1944 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; |
1945 | /* |
1946 | * Leave the last 3% for root |
1947 | */ |
1948 | if (!cap_sys_admin) |
1949 | allowed -= allowed / 32; |
1950 | allowed += total_swap_pages; |
1951 | |
1952 | /* Don't let a single process grow too big: |
1953 | leave 3% of the size of this process for other processes */ |
1954 | if (mm) |
1955 | allowed -= mm->total_vm / 32; |
1956 | |
1957 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1958 | return 0; |
1959 | |
1960 | error: |
1961 | vm_unacct_memory(pages); |
1962 | |
1963 | return -ENOMEM; |
1964 | } |
1965 | |
1966 | int in_gate_area_no_task(unsigned long addr) |
1967 | { |
1968 | return 0; |
1969 | } |
1970 | |
1971 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1972 | { |
1973 | BUG(); |
1974 | return 0; |
1975 | } |
1976 | EXPORT_SYMBOL(filemap_fault); |
1977 | |
1978 | /* |
1979 | * Access another process' address space. |
1980 | * - source/target buffer must be kernel space |
1981 | */ |
1982 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) |
1983 | { |
1984 | struct vm_area_struct *vma; |
1985 | struct mm_struct *mm; |
1986 | |
1987 | if (addr + len < addr) |
1988 | return 0; |
1989 | |
1990 | mm = get_task_mm(tsk); |
1991 | if (!mm) |
1992 | return 0; |
1993 | |
1994 | down_read(&mm->mmap_sem); |
1995 | |
1996 | /* the access must start within one of the target process's mappings */ |
1997 | vma = find_vma(mm, addr); |
1998 | if (vma) { |
1999 | /* don't overrun this mapping */ |
2000 | if (addr + len >= vma->vm_end) |
2001 | len = vma->vm_end - addr; |
2002 | |
2003 | /* only read or write mappings where it is permitted */ |
2004 | if (write && vma->vm_flags & VM_MAYWRITE) |
2005 | copy_to_user_page(vma, NULL, addr, |
2006 | (void *) addr, buf, len); |
2007 | else if (!write && vma->vm_flags & VM_MAYREAD) |
2008 | copy_from_user_page(vma, NULL, addr, |
2009 | buf, (void *) addr, len); |
2010 | else |
2011 | len = 0; |
2012 | } else { |
2013 | len = 0; |
2014 | } |
2015 | |
2016 | up_read(&mm->mmap_sem); |
2017 | mmput(mm); |
2018 | return len; |
2019 | } |
2020 | |
2021 | /** |
2022 | * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode |
2023 | * @inode: The inode to check |
2024 | * @size: The current filesize of the inode |
2025 | * @newsize: The proposed filesize of the inode |
2026 | * |
2027 | * Check the shared mappings on an inode on behalf of a shrinking truncate to |
2028 | * make sure that that any outstanding VMAs aren't broken and then shrink the |
2029 | * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't |
2030 | * automatically grant mappings that are too large. |
2031 | */ |
2032 | int nommu_shrink_inode_mappings(struct inode *inode, size_t size, |
2033 | size_t newsize) |
2034 | { |
2035 | struct vm_area_struct *vma; |
2036 | struct prio_tree_iter iter; |
2037 | struct vm_region *region; |
2038 | pgoff_t low, high; |
2039 | size_t r_size, r_top; |
2040 | |
2041 | low = newsize >> PAGE_SHIFT; |
2042 | high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
2043 | |
2044 | down_write(&nommu_region_sem); |
2045 | |
2046 | /* search for VMAs that fall within the dead zone */ |
2047 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, |
2048 | low, high) { |
2049 | /* found one - only interested if it's shared out of the page |
2050 | * cache */ |
2051 | if (vma->vm_flags & VM_SHARED) { |
2052 | up_write(&nommu_region_sem); |
2053 | return -ETXTBSY; /* not quite true, but near enough */ |
2054 | } |
2055 | } |
2056 | |
2057 | /* reduce any regions that overlap the dead zone - if in existence, |
2058 | * these will be pointed to by VMAs that don't overlap the dead zone |
2059 | * |
2060 | * we don't check for any regions that start beyond the EOF as there |
2061 | * shouldn't be any |
2062 | */ |
2063 | vma_prio_tree_foreach(vma, &iter, &inode->i_mapping->i_mmap, |
2064 | 0, ULONG_MAX) { |
2065 | if (!(vma->vm_flags & VM_SHARED)) |
2066 | continue; |
2067 | |
2068 | region = vma->vm_region; |
2069 | r_size = region->vm_top - region->vm_start; |
2070 | r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; |
2071 | |
2072 | if (r_top > newsize) { |
2073 | region->vm_top -= r_top - newsize; |
2074 | if (region->vm_end > region->vm_top) |
2075 | region->vm_end = region->vm_top; |
2076 | } |
2077 | } |
2078 | |
2079 | up_write(&nommu_region_sem); |
2080 | return 0; |
2081 | } |
2082 |
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