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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/export.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/blkdev.h> |
26 | #include <linux/backing-dev.h> |
27 | #include <linux/mount.h> |
28 | #include <linux/personality.h> |
29 | #include <linux/security.h> |
30 | #include <linux/syscalls.h> |
31 | #include <linux/audit.h> |
32 | #include <linux/sched/sysctl.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 | /* |
71 | * The global memory commitment made in the system can be a metric |
72 | * that can be used to drive ballooning decisions when Linux is hosted |
73 | * as a guest. On Hyper-V, the host implements a policy engine for dynamically |
74 | * balancing memory across competing virtual machines that are hosted. |
75 | * Several metrics drive this policy engine including the guest reported |
76 | * memory commitment. |
77 | */ |
78 | unsigned long vm_memory_committed(void) |
79 | { |
80 | return percpu_counter_read_positive(&vm_committed_as); |
81 | } |
82 | |
83 | EXPORT_SYMBOL_GPL(vm_memory_committed); |
84 | |
85 | EXPORT_SYMBOL(mem_map); |
86 | EXPORT_SYMBOL(num_physpages); |
87 | |
88 | /* list of mapped, potentially shareable regions */ |
89 | static struct kmem_cache *vm_region_jar; |
90 | struct rb_root nommu_region_tree = RB_ROOT; |
91 | DECLARE_RWSEM(nommu_region_sem); |
92 | |
93 | const struct vm_operations_struct generic_file_vm_ops = { |
94 | }; |
95 | |
96 | /* |
97 | * Return the total memory allocated for this pointer, not |
98 | * just what the caller asked for. |
99 | * |
100 | * Doesn't have to be accurate, i.e. may have races. |
101 | */ |
102 | unsigned int kobjsize(const void *objp) |
103 | { |
104 | struct page *page; |
105 | |
106 | /* |
107 | * If the object we have should not have ksize performed on it, |
108 | * return size of 0 |
109 | */ |
110 | if (!objp || !virt_addr_valid(objp)) |
111 | return 0; |
112 | |
113 | page = virt_to_head_page(objp); |
114 | |
115 | /* |
116 | * If the allocator sets PageSlab, we know the pointer came from |
117 | * kmalloc(). |
118 | */ |
119 | if (PageSlab(page)) |
120 | return ksize(objp); |
121 | |
122 | /* |
123 | * If it's not a compound page, see if we have a matching VMA |
124 | * region. This test is intentionally done in reverse order, |
125 | * so if there's no VMA, we still fall through and hand back |
126 | * PAGE_SIZE for 0-order pages. |
127 | */ |
128 | if (!PageCompound(page)) { |
129 | struct vm_area_struct *vma; |
130 | |
131 | vma = find_vma(current->mm, (unsigned long)objp); |
132 | if (vma) |
133 | return vma->vm_end - vma->vm_start; |
134 | } |
135 | |
136 | /* |
137 | * The ksize() function is only guaranteed to work for pointers |
138 | * returned by kmalloc(). So handle arbitrary pointers here. |
139 | */ |
140 | return PAGE_SIZE << compound_order(page); |
141 | } |
142 | |
143 | long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
144 | unsigned long start, unsigned long nr_pages, |
145 | unsigned int foll_flags, struct page **pages, |
146 | struct vm_area_struct **vmas, int *nonblocking) |
147 | { |
148 | struct vm_area_struct *vma; |
149 | unsigned long vm_flags; |
150 | int i; |
151 | |
152 | /* calculate required read or write permissions. |
153 | * If FOLL_FORCE is set, we only require the "MAY" flags. |
154 | */ |
155 | vm_flags = (foll_flags & FOLL_WRITE) ? |
156 | (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
157 | vm_flags &= (foll_flags & FOLL_FORCE) ? |
158 | (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
159 | |
160 | for (i = 0; i < nr_pages; i++) { |
161 | vma = find_vma(mm, start); |
162 | if (!vma) |
163 | goto finish_or_fault; |
164 | |
165 | /* protect what we can, including chardevs */ |
166 | if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) || |
167 | !(vm_flags & vma->vm_flags)) |
168 | goto finish_or_fault; |
169 | |
170 | if (pages) { |
171 | pages[i] = virt_to_page(start); |
172 | if (pages[i]) |
173 | page_cache_get(pages[i]); |
174 | } |
175 | if (vmas) |
176 | vmas[i] = vma; |
177 | start = (start + PAGE_SIZE) & PAGE_MASK; |
178 | } |
179 | |
180 | return i; |
181 | |
182 | finish_or_fault: |
183 | return i ? : -EFAULT; |
184 | } |
185 | |
186 | /* |
187 | * get a list of pages in an address range belonging to the specified process |
188 | * and indicate the VMA that covers each page |
189 | * - this is potentially dodgy as we may end incrementing the page count of a |
190 | * slab page or a secondary page from a compound page |
191 | * - don't permit access to VMAs that don't support it, such as I/O mappings |
192 | */ |
193 | long get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
194 | unsigned long start, unsigned long nr_pages, |
195 | int write, int force, struct page **pages, |
196 | struct vm_area_struct **vmas) |
197 | { |
198 | int flags = 0; |
199 | |
200 | if (write) |
201 | flags |= FOLL_WRITE; |
202 | if (force) |
203 | flags |= FOLL_FORCE; |
204 | |
205 | return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas, |
206 | NULL); |
207 | } |
208 | EXPORT_SYMBOL(get_user_pages); |
209 | |
210 | /** |
211 | * follow_pfn - look up PFN at a user virtual address |
212 | * @vma: memory mapping |
213 | * @address: user virtual address |
214 | * @pfn: location to store found PFN |
215 | * |
216 | * Only IO mappings and raw PFN mappings are allowed. |
217 | * |
218 | * Returns zero and the pfn at @pfn on success, -ve otherwise. |
219 | */ |
220 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, |
221 | unsigned long *pfn) |
222 | { |
223 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
224 | return -EINVAL; |
225 | |
226 | *pfn = address >> PAGE_SHIFT; |
227 | return 0; |
228 | } |
229 | EXPORT_SYMBOL(follow_pfn); |
230 | |
231 | DEFINE_RWLOCK(vmlist_lock); |
232 | struct vm_struct *vmlist; |
233 | |
234 | void vfree(const void *addr) |
235 | { |
236 | kfree(addr); |
237 | } |
238 | EXPORT_SYMBOL(vfree); |
239 | |
240 | void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot) |
241 | { |
242 | /* |
243 | * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc() |
244 | * returns only a logical address. |
245 | */ |
246 | return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM); |
247 | } |
248 | EXPORT_SYMBOL(__vmalloc); |
249 | |
250 | void *vmalloc_user(unsigned long size) |
251 | { |
252 | void *ret; |
253 | |
254 | ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, |
255 | PAGE_KERNEL); |
256 | if (ret) { |
257 | struct vm_area_struct *vma; |
258 | |
259 | down_write(¤t->mm->mmap_sem); |
260 | vma = find_vma(current->mm, (unsigned long)ret); |
261 | if (vma) |
262 | vma->vm_flags |= VM_USERMAP; |
263 | up_write(¤t->mm->mmap_sem); |
264 | } |
265 | |
266 | return ret; |
267 | } |
268 | EXPORT_SYMBOL(vmalloc_user); |
269 | |
270 | struct page *vmalloc_to_page(const void *addr) |
271 | { |
272 | return virt_to_page(addr); |
273 | } |
274 | EXPORT_SYMBOL(vmalloc_to_page); |
275 | |
276 | unsigned long vmalloc_to_pfn(const void *addr) |
277 | { |
278 | return page_to_pfn(virt_to_page(addr)); |
279 | } |
280 | EXPORT_SYMBOL(vmalloc_to_pfn); |
281 | |
282 | long vread(char *buf, char *addr, unsigned long count) |
283 | { |
284 | memcpy(buf, addr, count); |
285 | return count; |
286 | } |
287 | |
288 | long vwrite(char *buf, char *addr, unsigned long count) |
289 | { |
290 | /* Don't allow overflow */ |
291 | if ((unsigned long) addr + count < count) |
292 | count = -(unsigned long) addr; |
293 | |
294 | memcpy(addr, buf, count); |
295 | return(count); |
296 | } |
297 | |
298 | /* |
299 | * vmalloc - allocate virtually continguos memory |
300 | * |
301 | * @size: allocation size |
302 | * |
303 | * Allocate enough pages to cover @size from the page level |
304 | * allocator and map them into continguos kernel virtual space. |
305 | * |
306 | * For tight control over page level allocator and protection flags |
307 | * use __vmalloc() instead. |
308 | */ |
309 | void *vmalloc(unsigned long size) |
310 | { |
311 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL); |
312 | } |
313 | EXPORT_SYMBOL(vmalloc); |
314 | |
315 | /* |
316 | * vzalloc - allocate virtually continguos memory with zero fill |
317 | * |
318 | * @size: allocation size |
319 | * |
320 | * Allocate enough pages to cover @size from the page level |
321 | * allocator and map them into continguos kernel virtual space. |
322 | * The memory allocated is set to zero. |
323 | * |
324 | * For tight control over page level allocator and protection flags |
325 | * use __vmalloc() instead. |
326 | */ |
327 | void *vzalloc(unsigned long size) |
328 | { |
329 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO, |
330 | PAGE_KERNEL); |
331 | } |
332 | EXPORT_SYMBOL(vzalloc); |
333 | |
334 | /** |
335 | * vmalloc_node - allocate memory on a specific node |
336 | * @size: allocation size |
337 | * @node: numa node |
338 | * |
339 | * Allocate enough pages to cover @size from the page level |
340 | * allocator and map them into contiguous kernel virtual space. |
341 | * |
342 | * For tight control over page level allocator and protection flags |
343 | * use __vmalloc() instead. |
344 | */ |
345 | void *vmalloc_node(unsigned long size, int node) |
346 | { |
347 | return vmalloc(size); |
348 | } |
349 | EXPORT_SYMBOL(vmalloc_node); |
350 | |
351 | /** |
352 | * vzalloc_node - allocate memory on a specific node with zero fill |
353 | * @size: allocation size |
354 | * @node: numa node |
355 | * |
356 | * Allocate enough pages to cover @size from the page level |
357 | * allocator and map them into contiguous kernel virtual space. |
358 | * The memory allocated is set to zero. |
359 | * |
360 | * For tight control over page level allocator and protection flags |
361 | * use __vmalloc() instead. |
362 | */ |
363 | void *vzalloc_node(unsigned long size, int node) |
364 | { |
365 | return vzalloc(size); |
366 | } |
367 | EXPORT_SYMBOL(vzalloc_node); |
368 | |
369 | #ifndef PAGE_KERNEL_EXEC |
370 | # define PAGE_KERNEL_EXEC PAGE_KERNEL |
371 | #endif |
372 | |
373 | /** |
374 | * vmalloc_exec - allocate virtually contiguous, executable memory |
375 | * @size: allocation size |
376 | * |
377 | * Kernel-internal function to allocate enough pages to cover @size |
378 | * the page level allocator and map them into contiguous and |
379 | * executable kernel virtual space. |
380 | * |
381 | * For tight control over page level allocator and protection flags |
382 | * use __vmalloc() instead. |
383 | */ |
384 | |
385 | void *vmalloc_exec(unsigned long size) |
386 | { |
387 | return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC); |
388 | } |
389 | |
390 | /** |
391 | * vmalloc_32 - allocate virtually contiguous memory (32bit addressable) |
392 | * @size: allocation size |
393 | * |
394 | * Allocate enough 32bit PA addressable pages to cover @size from the |
395 | * page level allocator and map them into continguos kernel virtual space. |
396 | */ |
397 | void *vmalloc_32(unsigned long size) |
398 | { |
399 | return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL); |
400 | } |
401 | EXPORT_SYMBOL(vmalloc_32); |
402 | |
403 | /** |
404 | * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory |
405 | * @size: allocation size |
406 | * |
407 | * The resulting memory area is 32bit addressable and zeroed so it can be |
408 | * mapped to userspace without leaking data. |
409 | * |
410 | * VM_USERMAP is set on the corresponding VMA so that subsequent calls to |
411 | * remap_vmalloc_range() are permissible. |
412 | */ |
413 | void *vmalloc_32_user(unsigned long size) |
414 | { |
415 | /* |
416 | * We'll have to sort out the ZONE_DMA bits for 64-bit, |
417 | * but for now this can simply use vmalloc_user() directly. |
418 | */ |
419 | return vmalloc_user(size); |
420 | } |
421 | EXPORT_SYMBOL(vmalloc_32_user); |
422 | |
423 | void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot) |
424 | { |
425 | BUG(); |
426 | return NULL; |
427 | } |
428 | EXPORT_SYMBOL(vmap); |
429 | |
430 | void vunmap(const void *addr) |
431 | { |
432 | BUG(); |
433 | } |
434 | EXPORT_SYMBOL(vunmap); |
435 | |
436 | void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot) |
437 | { |
438 | BUG(); |
439 | return NULL; |
440 | } |
441 | EXPORT_SYMBOL(vm_map_ram); |
442 | |
443 | void vm_unmap_ram(const void *mem, unsigned int count) |
444 | { |
445 | BUG(); |
446 | } |
447 | EXPORT_SYMBOL(vm_unmap_ram); |
448 | |
449 | void vm_unmap_aliases(void) |
450 | { |
451 | } |
452 | EXPORT_SYMBOL_GPL(vm_unmap_aliases); |
453 | |
454 | /* |
455 | * Implement a stub for vmalloc_sync_all() if the architecture chose not to |
456 | * have one. |
457 | */ |
458 | void __attribute__((weak)) vmalloc_sync_all(void) |
459 | { |
460 | } |
461 | |
462 | /** |
463 | * alloc_vm_area - allocate a range of kernel address space |
464 | * @size: size of the area |
465 | * |
466 | * Returns: NULL on failure, vm_struct on success |
467 | * |
468 | * This function reserves a range of kernel address space, and |
469 | * allocates pagetables to map that range. No actual mappings |
470 | * are created. If the kernel address space is not shared |
471 | * between processes, it syncs the pagetable across all |
472 | * processes. |
473 | */ |
474 | struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes) |
475 | { |
476 | BUG(); |
477 | return NULL; |
478 | } |
479 | EXPORT_SYMBOL_GPL(alloc_vm_area); |
480 | |
481 | void free_vm_area(struct vm_struct *area) |
482 | { |
483 | BUG(); |
484 | } |
485 | EXPORT_SYMBOL_GPL(free_vm_area); |
486 | |
487 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
488 | struct page *page) |
489 | { |
490 | return -EINVAL; |
491 | } |
492 | EXPORT_SYMBOL(vm_insert_page); |
493 | |
494 | /* |
495 | * sys_brk() for the most part doesn't need the global kernel |
496 | * lock, except when an application is doing something nasty |
497 | * like trying to un-brk an area that has already been mapped |
498 | * to a regular file. in this case, the unmapping will need |
499 | * to invoke file system routines that need the global lock. |
500 | */ |
501 | SYSCALL_DEFINE1(brk, unsigned long, brk) |
502 | { |
503 | struct mm_struct *mm = current->mm; |
504 | |
505 | if (brk < mm->start_brk || brk > mm->context.end_brk) |
506 | return mm->brk; |
507 | |
508 | if (mm->brk == brk) |
509 | return mm->brk; |
510 | |
511 | /* |
512 | * Always allow shrinking brk |
513 | */ |
514 | if (brk <= mm->brk) { |
515 | mm->brk = brk; |
516 | return brk; |
517 | } |
518 | |
519 | /* |
520 | * Ok, looks good - let it rip. |
521 | */ |
522 | flush_icache_range(mm->brk, brk); |
523 | return mm->brk = brk; |
524 | } |
525 | |
526 | /* |
527 | * initialise the VMA and region record slabs |
528 | */ |
529 | void __init mmap_init(void) |
530 | { |
531 | int ret; |
532 | |
533 | ret = percpu_counter_init(&vm_committed_as, 0); |
534 | VM_BUG_ON(ret); |
535 | vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC); |
536 | } |
537 | |
538 | /* |
539 | * validate the region tree |
540 | * - the caller must hold the region lock |
541 | */ |
542 | #ifdef CONFIG_DEBUG_NOMMU_REGIONS |
543 | static noinline void validate_nommu_regions(void) |
544 | { |
545 | struct vm_region *region, *last; |
546 | struct rb_node *p, *lastp; |
547 | |
548 | lastp = rb_first(&nommu_region_tree); |
549 | if (!lastp) |
550 | return; |
551 | |
552 | last = rb_entry(lastp, struct vm_region, vm_rb); |
553 | BUG_ON(unlikely(last->vm_end <= last->vm_start)); |
554 | BUG_ON(unlikely(last->vm_top < last->vm_end)); |
555 | |
556 | while ((p = rb_next(lastp))) { |
557 | region = rb_entry(p, struct vm_region, vm_rb); |
558 | last = rb_entry(lastp, struct vm_region, vm_rb); |
559 | |
560 | BUG_ON(unlikely(region->vm_end <= region->vm_start)); |
561 | BUG_ON(unlikely(region->vm_top < region->vm_end)); |
562 | BUG_ON(unlikely(region->vm_start < last->vm_top)); |
563 | |
564 | lastp = p; |
565 | } |
566 | } |
567 | #else |
568 | static void validate_nommu_regions(void) |
569 | { |
570 | } |
571 | #endif |
572 | |
573 | /* |
574 | * add a region into the global tree |
575 | */ |
576 | static void add_nommu_region(struct vm_region *region) |
577 | { |
578 | struct vm_region *pregion; |
579 | struct rb_node **p, *parent; |
580 | |
581 | validate_nommu_regions(); |
582 | |
583 | parent = NULL; |
584 | p = &nommu_region_tree.rb_node; |
585 | while (*p) { |
586 | parent = *p; |
587 | pregion = rb_entry(parent, struct vm_region, vm_rb); |
588 | if (region->vm_start < pregion->vm_start) |
589 | p = &(*p)->rb_left; |
590 | else if (region->vm_start > pregion->vm_start) |
591 | p = &(*p)->rb_right; |
592 | else if (pregion == region) |
593 | return; |
594 | else |
595 | BUG(); |
596 | } |
597 | |
598 | rb_link_node(®ion->vm_rb, parent, p); |
599 | rb_insert_color(®ion->vm_rb, &nommu_region_tree); |
600 | |
601 | validate_nommu_regions(); |
602 | } |
603 | |
604 | /* |
605 | * delete a region from the global tree |
606 | */ |
607 | static void delete_nommu_region(struct vm_region *region) |
608 | { |
609 | BUG_ON(!nommu_region_tree.rb_node); |
610 | |
611 | validate_nommu_regions(); |
612 | rb_erase(®ion->vm_rb, &nommu_region_tree); |
613 | validate_nommu_regions(); |
614 | } |
615 | |
616 | /* |
617 | * free a contiguous series of pages |
618 | */ |
619 | static void free_page_series(unsigned long from, unsigned long to) |
620 | { |
621 | for (; from < to; from += PAGE_SIZE) { |
622 | struct page *page = virt_to_page(from); |
623 | |
624 | kdebug("- free %lx", from); |
625 | atomic_long_dec(&mmap_pages_allocated); |
626 | if (page_count(page) != 1) |
627 | kdebug("free page %p: refcount not one: %d", |
628 | page, page_count(page)); |
629 | put_page(page); |
630 | } |
631 | } |
632 | |
633 | /* |
634 | * release a reference to a region |
635 | * - the caller must hold the region semaphore for writing, which this releases |
636 | * - the region may not have been added to the tree yet, in which case vm_top |
637 | * will equal vm_start |
638 | */ |
639 | static void __put_nommu_region(struct vm_region *region) |
640 | __releases(nommu_region_sem) |
641 | { |
642 | kenter("%p{%d}", region, region->vm_usage); |
643 | |
644 | BUG_ON(!nommu_region_tree.rb_node); |
645 | |
646 | if (--region->vm_usage == 0) { |
647 | if (region->vm_top > region->vm_start) |
648 | delete_nommu_region(region); |
649 | up_write(&nommu_region_sem); |
650 | |
651 | if (region->vm_file) |
652 | fput(region->vm_file); |
653 | |
654 | /* IO memory and memory shared directly out of the pagecache |
655 | * from ramfs/tmpfs mustn't be released here */ |
656 | if (region->vm_flags & VM_MAPPED_COPY) { |
657 | kdebug("free series"); |
658 | free_page_series(region->vm_start, region->vm_top); |
659 | } |
660 | kmem_cache_free(vm_region_jar, region); |
661 | } else { |
662 | up_write(&nommu_region_sem); |
663 | } |
664 | } |
665 | |
666 | /* |
667 | * release a reference to a region |
668 | */ |
669 | static void put_nommu_region(struct vm_region *region) |
670 | { |
671 | down_write(&nommu_region_sem); |
672 | __put_nommu_region(region); |
673 | } |
674 | |
675 | /* |
676 | * update protection on a vma |
677 | */ |
678 | static void protect_vma(struct vm_area_struct *vma, unsigned long flags) |
679 | { |
680 | #ifdef CONFIG_MPU |
681 | struct mm_struct *mm = vma->vm_mm; |
682 | long start = vma->vm_start & PAGE_MASK; |
683 | while (start < vma->vm_end) { |
684 | protect_page(mm, start, flags); |
685 | start += PAGE_SIZE; |
686 | } |
687 | update_protections(mm); |
688 | #endif |
689 | } |
690 | |
691 | /* |
692 | * add a VMA into a process's mm_struct in the appropriate place in the list |
693 | * and tree and add to the address space's page tree also if not an anonymous |
694 | * page |
695 | * - should be called with mm->mmap_sem held writelocked |
696 | */ |
697 | static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma) |
698 | { |
699 | struct vm_area_struct *pvma, *prev; |
700 | struct address_space *mapping; |
701 | struct rb_node **p, *parent, *rb_prev; |
702 | |
703 | kenter(",%p", vma); |
704 | |
705 | BUG_ON(!vma->vm_region); |
706 | |
707 | mm->map_count++; |
708 | vma->vm_mm = mm; |
709 | |
710 | protect_vma(vma, vma->vm_flags); |
711 | |
712 | /* add the VMA to the mapping */ |
713 | if (vma->vm_file) { |
714 | mapping = vma->vm_file->f_mapping; |
715 | |
716 | mutex_lock(&mapping->i_mmap_mutex); |
717 | flush_dcache_mmap_lock(mapping); |
718 | vma_interval_tree_insert(vma, &mapping->i_mmap); |
719 | flush_dcache_mmap_unlock(mapping); |
720 | mutex_unlock(&mapping->i_mmap_mutex); |
721 | } |
722 | |
723 | /* add the VMA to the tree */ |
724 | parent = rb_prev = NULL; |
725 | p = &mm->mm_rb.rb_node; |
726 | while (*p) { |
727 | parent = *p; |
728 | pvma = rb_entry(parent, struct vm_area_struct, vm_rb); |
729 | |
730 | /* sort by: start addr, end addr, VMA struct addr in that order |
731 | * (the latter is necessary as we may get identical VMAs) */ |
732 | if (vma->vm_start < pvma->vm_start) |
733 | p = &(*p)->rb_left; |
734 | else if (vma->vm_start > pvma->vm_start) { |
735 | rb_prev = parent; |
736 | p = &(*p)->rb_right; |
737 | } else if (vma->vm_end < pvma->vm_end) |
738 | p = &(*p)->rb_left; |
739 | else if (vma->vm_end > pvma->vm_end) { |
740 | rb_prev = parent; |
741 | p = &(*p)->rb_right; |
742 | } else if (vma < pvma) |
743 | p = &(*p)->rb_left; |
744 | else if (vma > pvma) { |
745 | rb_prev = parent; |
746 | p = &(*p)->rb_right; |
747 | } else |
748 | BUG(); |
749 | } |
750 | |
751 | rb_link_node(&vma->vm_rb, parent, p); |
752 | rb_insert_color(&vma->vm_rb, &mm->mm_rb); |
753 | |
754 | /* add VMA to the VMA list also */ |
755 | prev = NULL; |
756 | if (rb_prev) |
757 | prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
758 | |
759 | __vma_link_list(mm, vma, prev, parent); |
760 | } |
761 | |
762 | /* |
763 | * delete a VMA from its owning mm_struct and address space |
764 | */ |
765 | static void delete_vma_from_mm(struct vm_area_struct *vma) |
766 | { |
767 | struct address_space *mapping; |
768 | struct mm_struct *mm = vma->vm_mm; |
769 | |
770 | kenter("%p", vma); |
771 | |
772 | protect_vma(vma, 0); |
773 | |
774 | mm->map_count--; |
775 | if (mm->mmap_cache == vma) |
776 | mm->mmap_cache = NULL; |
777 | |
778 | /* remove the VMA from the mapping */ |
779 | if (vma->vm_file) { |
780 | mapping = vma->vm_file->f_mapping; |
781 | |
782 | mutex_lock(&mapping->i_mmap_mutex); |
783 | flush_dcache_mmap_lock(mapping); |
784 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
785 | flush_dcache_mmap_unlock(mapping); |
786 | mutex_unlock(&mapping->i_mmap_mutex); |
787 | } |
788 | |
789 | /* remove from the MM's tree and list */ |
790 | rb_erase(&vma->vm_rb, &mm->mm_rb); |
791 | |
792 | if (vma->vm_prev) |
793 | vma->vm_prev->vm_next = vma->vm_next; |
794 | else |
795 | mm->mmap = vma->vm_next; |
796 | |
797 | if (vma->vm_next) |
798 | vma->vm_next->vm_prev = vma->vm_prev; |
799 | } |
800 | |
801 | /* |
802 | * destroy a VMA record |
803 | */ |
804 | static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) |
805 | { |
806 | kenter("%p", vma); |
807 | if (vma->vm_ops && vma->vm_ops->close) |
808 | vma->vm_ops->close(vma); |
809 | if (vma->vm_file) |
810 | fput(vma->vm_file); |
811 | put_nommu_region(vma->vm_region); |
812 | kmem_cache_free(vm_area_cachep, vma); |
813 | } |
814 | |
815 | /* |
816 | * look up the first VMA in which addr resides, NULL if none |
817 | * - should be called with mm->mmap_sem at least held readlocked |
818 | */ |
819 | struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) |
820 | { |
821 | struct vm_area_struct *vma; |
822 | |
823 | /* check the cache first */ |
824 | vma = ACCESS_ONCE(mm->mmap_cache); |
825 | if (vma && vma->vm_start <= addr && vma->vm_end > addr) |
826 | return vma; |
827 | |
828 | /* trawl the list (there may be multiple mappings in which addr |
829 | * resides) */ |
830 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
831 | if (vma->vm_start > addr) |
832 | return NULL; |
833 | if (vma->vm_end > addr) { |
834 | mm->mmap_cache = vma; |
835 | return vma; |
836 | } |
837 | } |
838 | |
839 | return NULL; |
840 | } |
841 | EXPORT_SYMBOL(find_vma); |
842 | |
843 | /* |
844 | * find a VMA |
845 | * - we don't extend stack VMAs under NOMMU conditions |
846 | */ |
847 | struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr) |
848 | { |
849 | return find_vma(mm, addr); |
850 | } |
851 | |
852 | /* |
853 | * expand a stack to a given address |
854 | * - not supported under NOMMU conditions |
855 | */ |
856 | int expand_stack(struct vm_area_struct *vma, unsigned long address) |
857 | { |
858 | return -ENOMEM; |
859 | } |
860 | |
861 | /* |
862 | * look up the first VMA exactly that exactly matches addr |
863 | * - should be called with mm->mmap_sem at least held readlocked |
864 | */ |
865 | static struct vm_area_struct *find_vma_exact(struct mm_struct *mm, |
866 | unsigned long addr, |
867 | unsigned long len) |
868 | { |
869 | struct vm_area_struct *vma; |
870 | unsigned long end = addr + len; |
871 | |
872 | /* check the cache first */ |
873 | vma = mm->mmap_cache; |
874 | if (vma && vma->vm_start == addr && vma->vm_end == end) |
875 | return vma; |
876 | |
877 | /* trawl the list (there may be multiple mappings in which addr |
878 | * resides) */ |
879 | for (vma = mm->mmap; vma; vma = vma->vm_next) { |
880 | if (vma->vm_start < addr) |
881 | continue; |
882 | if (vma->vm_start > addr) |
883 | return NULL; |
884 | if (vma->vm_end == end) { |
885 | mm->mmap_cache = vma; |
886 | return vma; |
887 | } |
888 | } |
889 | |
890 | return NULL; |
891 | } |
892 | |
893 | /* |
894 | * determine whether a mapping should be permitted and, if so, what sort of |
895 | * mapping we're capable of supporting |
896 | */ |
897 | static int validate_mmap_request(struct file *file, |
898 | unsigned long addr, |
899 | unsigned long len, |
900 | unsigned long prot, |
901 | unsigned long flags, |
902 | unsigned long pgoff, |
903 | unsigned long *_capabilities) |
904 | { |
905 | unsigned long capabilities, rlen; |
906 | int ret; |
907 | |
908 | /* do the simple checks first */ |
909 | if (flags & MAP_FIXED) { |
910 | printk(KERN_DEBUG |
911 | "%d: Can't do fixed-address/overlay mmap of RAM\n", |
912 | current->pid); |
913 | return -EINVAL; |
914 | } |
915 | |
916 | if ((flags & MAP_TYPE) != MAP_PRIVATE && |
917 | (flags & MAP_TYPE) != MAP_SHARED) |
918 | return -EINVAL; |
919 | |
920 | if (!len) |
921 | return -EINVAL; |
922 | |
923 | /* Careful about overflows.. */ |
924 | rlen = PAGE_ALIGN(len); |
925 | if (!rlen || rlen > TASK_SIZE) |
926 | return -ENOMEM; |
927 | |
928 | /* offset overflow? */ |
929 | if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff) |
930 | return -EOVERFLOW; |
931 | |
932 | if (file) { |
933 | /* validate file mapping requests */ |
934 | struct address_space *mapping; |
935 | |
936 | /* files must support mmap */ |
937 | if (!file->f_op || !file->f_op->mmap) |
938 | return -ENODEV; |
939 | |
940 | /* work out if what we've got could possibly be shared |
941 | * - we support chardevs that provide their own "memory" |
942 | * - we support files/blockdevs that are memory backed |
943 | */ |
944 | mapping = file->f_mapping; |
945 | if (!mapping) |
946 | mapping = file_inode(file)->i_mapping; |
947 | |
948 | capabilities = 0; |
949 | if (mapping && mapping->backing_dev_info) |
950 | capabilities = mapping->backing_dev_info->capabilities; |
951 | |
952 | if (!capabilities) { |
953 | /* no explicit capabilities set, so assume some |
954 | * defaults */ |
955 | switch (file_inode(file)->i_mode & S_IFMT) { |
956 | case S_IFREG: |
957 | case S_IFBLK: |
958 | capabilities = BDI_CAP_MAP_COPY; |
959 | break; |
960 | |
961 | case S_IFCHR: |
962 | capabilities = |
963 | BDI_CAP_MAP_DIRECT | |
964 | BDI_CAP_READ_MAP | |
965 | BDI_CAP_WRITE_MAP; |
966 | break; |
967 | |
968 | default: |
969 | return -EINVAL; |
970 | } |
971 | } |
972 | |
973 | /* eliminate any capabilities that we can't support on this |
974 | * device */ |
975 | if (!file->f_op->get_unmapped_area) |
976 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
977 | if (!file->f_op->read) |
978 | capabilities &= ~BDI_CAP_MAP_COPY; |
979 | |
980 | /* The file shall have been opened with read permission. */ |
981 | if (!(file->f_mode & FMODE_READ)) |
982 | return -EACCES; |
983 | |
984 | if (flags & MAP_SHARED) { |
985 | /* do checks for writing, appending and locking */ |
986 | if ((prot & PROT_WRITE) && |
987 | !(file->f_mode & FMODE_WRITE)) |
988 | return -EACCES; |
989 | |
990 | if (IS_APPEND(file_inode(file)) && |
991 | (file->f_mode & FMODE_WRITE)) |
992 | return -EACCES; |
993 | |
994 | if (locks_verify_locked(file_inode(file))) |
995 | return -EAGAIN; |
996 | |
997 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
998 | return -ENODEV; |
999 | |
1000 | /* we mustn't privatise shared mappings */ |
1001 | capabilities &= ~BDI_CAP_MAP_COPY; |
1002 | } |
1003 | else { |
1004 | /* we're going to read the file into private memory we |
1005 | * allocate */ |
1006 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
1007 | return -ENODEV; |
1008 | |
1009 | /* we don't permit a private writable mapping to be |
1010 | * shared with the backing device */ |
1011 | if (prot & PROT_WRITE) |
1012 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1013 | } |
1014 | |
1015 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1016 | if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) || |
1017 | ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) || |
1018 | ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP)) |
1019 | ) { |
1020 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1021 | if (flags & MAP_SHARED) { |
1022 | printk(KERN_WARNING |
1023 | "MAP_SHARED not completely supported on !MMU\n"); |
1024 | return -EINVAL; |
1025 | } |
1026 | } |
1027 | } |
1028 | |
1029 | /* handle executable mappings and implied executable |
1030 | * mappings */ |
1031 | if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) { |
1032 | if (prot & PROT_EXEC) |
1033 | return -EPERM; |
1034 | } |
1035 | else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) { |
1036 | /* handle implication of PROT_EXEC by PROT_READ */ |
1037 | if (current->personality & READ_IMPLIES_EXEC) { |
1038 | if (capabilities & BDI_CAP_EXEC_MAP) |
1039 | prot |= PROT_EXEC; |
1040 | } |
1041 | } |
1042 | else if ((prot & PROT_READ) && |
1043 | (prot & PROT_EXEC) && |
1044 | !(capabilities & BDI_CAP_EXEC_MAP) |
1045 | ) { |
1046 | /* backing file is not executable, try to copy */ |
1047 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1048 | } |
1049 | } |
1050 | else { |
1051 | /* anonymous mappings are always memory backed and can be |
1052 | * privately mapped |
1053 | */ |
1054 | capabilities = BDI_CAP_MAP_COPY; |
1055 | |
1056 | /* handle PROT_EXEC implication by PROT_READ */ |
1057 | if ((prot & PROT_READ) && |
1058 | (current->personality & READ_IMPLIES_EXEC)) |
1059 | prot |= PROT_EXEC; |
1060 | } |
1061 | |
1062 | /* allow the security API to have its say */ |
1063 | ret = security_mmap_addr(addr); |
1064 | if (ret < 0) |
1065 | return ret; |
1066 | |
1067 | /* looks okay */ |
1068 | *_capabilities = capabilities; |
1069 | return 0; |
1070 | } |
1071 | |
1072 | /* |
1073 | * we've determined that we can make the mapping, now translate what we |
1074 | * now know into VMA flags |
1075 | */ |
1076 | static unsigned long determine_vm_flags(struct file *file, |
1077 | unsigned long prot, |
1078 | unsigned long flags, |
1079 | unsigned long capabilities) |
1080 | { |
1081 | unsigned long vm_flags; |
1082 | |
1083 | vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags); |
1084 | /* vm_flags |= mm->def_flags; */ |
1085 | |
1086 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) { |
1087 | /* attempt to share read-only copies of mapped file chunks */ |
1088 | vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
1089 | if (file && !(prot & PROT_WRITE)) |
1090 | vm_flags |= VM_MAYSHARE; |
1091 | } else { |
1092 | /* overlay a shareable mapping on the backing device or inode |
1093 | * if possible - used for chardevs, ramfs/tmpfs/shmfs and |
1094 | * romfs/cramfs */ |
1095 | vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS); |
1096 | if (flags & MAP_SHARED) |
1097 | vm_flags |= VM_SHARED; |
1098 | } |
1099 | |
1100 | /* refuse to let anyone share private mappings with this process if |
1101 | * it's being traced - otherwise breakpoints set in it may interfere |
1102 | * with another untraced process |
1103 | */ |
1104 | if ((flags & MAP_PRIVATE) && current->ptrace) |
1105 | vm_flags &= ~VM_MAYSHARE; |
1106 | |
1107 | return vm_flags; |
1108 | } |
1109 | |
1110 | /* |
1111 | * set up a shared mapping on a file (the driver or filesystem provides and |
1112 | * pins the storage) |
1113 | */ |
1114 | static int do_mmap_shared_file(struct vm_area_struct *vma) |
1115 | { |
1116 | int ret; |
1117 | |
1118 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
1119 | if (ret == 0) { |
1120 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
1121 | return 0; |
1122 | } |
1123 | if (ret != -ENOSYS) |
1124 | return ret; |
1125 | |
1126 | /* getting -ENOSYS indicates that direct mmap isn't possible (as |
1127 | * opposed to tried but failed) so we can only give a suitable error as |
1128 | * it's not possible to make a private copy if MAP_SHARED was given */ |
1129 | return -ENODEV; |
1130 | } |
1131 | |
1132 | /* |
1133 | * set up a private mapping or an anonymous shared mapping |
1134 | */ |
1135 | static int do_mmap_private(struct vm_area_struct *vma, |
1136 | struct vm_region *region, |
1137 | unsigned long len, |
1138 | unsigned long capabilities) |
1139 | { |
1140 | struct page *pages; |
1141 | unsigned long total, point, n; |
1142 | void *base; |
1143 | int ret, order; |
1144 | |
1145 | /* invoke the file's mapping function so that it can keep track of |
1146 | * shared mappings on devices or memory |
1147 | * - VM_MAYSHARE will be set if it may attempt to share |
1148 | */ |
1149 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1150 | ret = vma->vm_file->f_op->mmap(vma->vm_file, vma); |
1151 | if (ret == 0) { |
1152 | /* shouldn't return success if we're not sharing */ |
1153 | BUG_ON(!(vma->vm_flags & VM_MAYSHARE)); |
1154 | vma->vm_region->vm_top = vma->vm_region->vm_end; |
1155 | return 0; |
1156 | } |
1157 | if (ret != -ENOSYS) |
1158 | return ret; |
1159 | |
1160 | /* getting an ENOSYS error indicates that direct mmap isn't |
1161 | * possible (as opposed to tried but failed) so we'll try to |
1162 | * make a private copy of the data and map that instead */ |
1163 | } |
1164 | |
1165 | |
1166 | /* allocate some memory to hold the mapping |
1167 | * - note that this may not return a page-aligned address if the object |
1168 | * we're allocating is smaller than a page |
1169 | */ |
1170 | order = get_order(len); |
1171 | kdebug("alloc order %d for %lx", order, len); |
1172 | |
1173 | pages = alloc_pages(GFP_KERNEL, order); |
1174 | if (!pages) |
1175 | goto enomem; |
1176 | |
1177 | total = 1 << order; |
1178 | atomic_long_add(total, &mmap_pages_allocated); |
1179 | |
1180 | point = len >> PAGE_SHIFT; |
1181 | |
1182 | /* we allocated a power-of-2 sized page set, so we may want to trim off |
1183 | * the excess */ |
1184 | if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) { |
1185 | while (total > point) { |
1186 | order = ilog2(total - point); |
1187 | n = 1 << order; |
1188 | kdebug("shave %lu/%lu @%lu", n, total - point, total); |
1189 | atomic_long_sub(n, &mmap_pages_allocated); |
1190 | total -= n; |
1191 | set_page_refcounted(pages + total); |
1192 | __free_pages(pages + total, order); |
1193 | } |
1194 | } |
1195 | |
1196 | for (point = 1; point < total; point++) |
1197 | set_page_refcounted(&pages[point]); |
1198 | |
1199 | base = page_address(pages); |
1200 | region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY; |
1201 | region->vm_start = (unsigned long) base; |
1202 | region->vm_end = region->vm_start + len; |
1203 | region->vm_top = region->vm_start + (total << PAGE_SHIFT); |
1204 | |
1205 | vma->vm_start = region->vm_start; |
1206 | vma->vm_end = region->vm_start + len; |
1207 | |
1208 | if (vma->vm_file) { |
1209 | /* read the contents of a file into the copy */ |
1210 | mm_segment_t old_fs; |
1211 | loff_t fpos; |
1212 | |
1213 | fpos = vma->vm_pgoff; |
1214 | fpos <<= PAGE_SHIFT; |
1215 | |
1216 | old_fs = get_fs(); |
1217 | set_fs(KERNEL_DS); |
1218 | ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos); |
1219 | set_fs(old_fs); |
1220 | |
1221 | if (ret < 0) |
1222 | goto error_free; |
1223 | |
1224 | /* clear the last little bit */ |
1225 | if (ret < len) |
1226 | memset(base + ret, 0, len - ret); |
1227 | |
1228 | } |
1229 | |
1230 | return 0; |
1231 | |
1232 | error_free: |
1233 | free_page_series(region->vm_start, region->vm_top); |
1234 | region->vm_start = vma->vm_start = 0; |
1235 | region->vm_end = vma->vm_end = 0; |
1236 | region->vm_top = 0; |
1237 | return ret; |
1238 | |
1239 | enomem: |
1240 | printk("Allocation of length %lu from process %d (%s) failed\n", |
1241 | len, current->pid, current->comm); |
1242 | show_free_areas(0); |
1243 | return -ENOMEM; |
1244 | } |
1245 | |
1246 | /* |
1247 | * handle mapping creation for uClinux |
1248 | */ |
1249 | unsigned long do_mmap_pgoff(struct file *file, |
1250 | unsigned long addr, |
1251 | unsigned long len, |
1252 | unsigned long prot, |
1253 | unsigned long flags, |
1254 | unsigned long pgoff, |
1255 | unsigned long *populate) |
1256 | { |
1257 | struct vm_area_struct *vma; |
1258 | struct vm_region *region; |
1259 | struct rb_node *rb; |
1260 | unsigned long capabilities, vm_flags, result; |
1261 | int ret; |
1262 | |
1263 | kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff); |
1264 | |
1265 | *populate = 0; |
1266 | |
1267 | /* decide whether we should attempt the mapping, and if so what sort of |
1268 | * mapping */ |
1269 | ret = validate_mmap_request(file, addr, len, prot, flags, pgoff, |
1270 | &capabilities); |
1271 | if (ret < 0) { |
1272 | kleave(" = %d [val]", ret); |
1273 | return ret; |
1274 | } |
1275 | |
1276 | /* we ignore the address hint */ |
1277 | addr = 0; |
1278 | len = PAGE_ALIGN(len); |
1279 | |
1280 | /* we've determined that we can make the mapping, now translate what we |
1281 | * now know into VMA flags */ |
1282 | vm_flags = determine_vm_flags(file, prot, flags, capabilities); |
1283 | |
1284 | /* we're going to need to record the mapping */ |
1285 | region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL); |
1286 | if (!region) |
1287 | goto error_getting_region; |
1288 | |
1289 | vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL); |
1290 | if (!vma) |
1291 | goto error_getting_vma; |
1292 | |
1293 | region->vm_usage = 1; |
1294 | region->vm_flags = vm_flags; |
1295 | region->vm_pgoff = pgoff; |
1296 | |
1297 | INIT_LIST_HEAD(&vma->anon_vma_chain); |
1298 | vma->vm_flags = vm_flags; |
1299 | vma->vm_pgoff = pgoff; |
1300 | |
1301 | if (file) { |
1302 | region->vm_file = get_file(file); |
1303 | vma->vm_file = get_file(file); |
1304 | } |
1305 | |
1306 | down_write(&nommu_region_sem); |
1307 | |
1308 | /* if we want to share, we need to check for regions created by other |
1309 | * mmap() calls that overlap with our proposed mapping |
1310 | * - we can only share with a superset match on most regular files |
1311 | * - shared mappings on character devices and memory backed files are |
1312 | * permitted to overlap inexactly as far as we are concerned for in |
1313 | * these cases, sharing is handled in the driver or filesystem rather |
1314 | * than here |
1315 | */ |
1316 | if (vm_flags & VM_MAYSHARE) { |
1317 | struct vm_region *pregion; |
1318 | unsigned long pglen, rpglen, pgend, rpgend, start; |
1319 | |
1320 | pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1321 | pgend = pgoff + pglen; |
1322 | |
1323 | for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) { |
1324 | pregion = rb_entry(rb, struct vm_region, vm_rb); |
1325 | |
1326 | if (!(pregion->vm_flags & VM_MAYSHARE)) |
1327 | continue; |
1328 | |
1329 | /* search for overlapping mappings on the same file */ |
1330 | if (file_inode(pregion->vm_file) != |
1331 | file_inode(file)) |
1332 | continue; |
1333 | |
1334 | if (pregion->vm_pgoff >= pgend) |
1335 | continue; |
1336 | |
1337 | rpglen = pregion->vm_end - pregion->vm_start; |
1338 | rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
1339 | rpgend = pregion->vm_pgoff + rpglen; |
1340 | if (pgoff >= rpgend) |
1341 | continue; |
1342 | |
1343 | /* handle inexactly overlapping matches between |
1344 | * mappings */ |
1345 | if ((pregion->vm_pgoff != pgoff || rpglen != pglen) && |
1346 | !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) { |
1347 | /* new mapping is not a subset of the region */ |
1348 | if (!(capabilities & BDI_CAP_MAP_DIRECT)) |
1349 | goto sharing_violation; |
1350 | continue; |
1351 | } |
1352 | |
1353 | /* we've found a region we can share */ |
1354 | pregion->vm_usage++; |
1355 | vma->vm_region = pregion; |
1356 | start = pregion->vm_start; |
1357 | start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT; |
1358 | vma->vm_start = start; |
1359 | vma->vm_end = start + len; |
1360 | |
1361 | if (pregion->vm_flags & VM_MAPPED_COPY) { |
1362 | kdebug("share copy"); |
1363 | vma->vm_flags |= VM_MAPPED_COPY; |
1364 | } else { |
1365 | kdebug("share mmap"); |
1366 | ret = do_mmap_shared_file(vma); |
1367 | if (ret < 0) { |
1368 | vma->vm_region = NULL; |
1369 | vma->vm_start = 0; |
1370 | vma->vm_end = 0; |
1371 | pregion->vm_usage--; |
1372 | pregion = NULL; |
1373 | goto error_just_free; |
1374 | } |
1375 | } |
1376 | fput(region->vm_file); |
1377 | kmem_cache_free(vm_region_jar, region); |
1378 | region = pregion; |
1379 | result = start; |
1380 | goto share; |
1381 | } |
1382 | |
1383 | /* obtain the address at which to make a shared mapping |
1384 | * - this is the hook for quasi-memory character devices to |
1385 | * tell us the location of a shared mapping |
1386 | */ |
1387 | if (capabilities & BDI_CAP_MAP_DIRECT) { |
1388 | addr = file->f_op->get_unmapped_area(file, addr, len, |
1389 | pgoff, flags); |
1390 | if (IS_ERR_VALUE(addr)) { |
1391 | ret = addr; |
1392 | if (ret != -ENOSYS) |
1393 | goto error_just_free; |
1394 | |
1395 | /* the driver refused to tell us where to site |
1396 | * the mapping so we'll have to attempt to copy |
1397 | * it */ |
1398 | ret = -ENODEV; |
1399 | if (!(capabilities & BDI_CAP_MAP_COPY)) |
1400 | goto error_just_free; |
1401 | |
1402 | capabilities &= ~BDI_CAP_MAP_DIRECT; |
1403 | } else { |
1404 | vma->vm_start = region->vm_start = addr; |
1405 | vma->vm_end = region->vm_end = addr + len; |
1406 | } |
1407 | } |
1408 | } |
1409 | |
1410 | vma->vm_region = region; |
1411 | |
1412 | /* set up the mapping |
1413 | * - the region is filled in if BDI_CAP_MAP_DIRECT is still set |
1414 | */ |
1415 | if (file && vma->vm_flags & VM_SHARED) |
1416 | ret = do_mmap_shared_file(vma); |
1417 | else |
1418 | ret = do_mmap_private(vma, region, len, capabilities); |
1419 | if (ret < 0) |
1420 | goto error_just_free; |
1421 | add_nommu_region(region); |
1422 | |
1423 | /* clear anonymous mappings that don't ask for uninitialized data */ |
1424 | if (!vma->vm_file && !(flags & MAP_UNINITIALIZED)) |
1425 | memset((void *)region->vm_start, 0, |
1426 | region->vm_end - region->vm_start); |
1427 | |
1428 | /* okay... we have a mapping; now we have to register it */ |
1429 | result = vma->vm_start; |
1430 | |
1431 | current->mm->total_vm += len >> PAGE_SHIFT; |
1432 | |
1433 | share: |
1434 | add_vma_to_mm(current->mm, vma); |
1435 | |
1436 | /* we flush the region from the icache only when the first executable |
1437 | * mapping of it is made */ |
1438 | if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) { |
1439 | flush_icache_range(region->vm_start, region->vm_end); |
1440 | region->vm_icache_flushed = true; |
1441 | } |
1442 | |
1443 | up_write(&nommu_region_sem); |
1444 | |
1445 | kleave(" = %lx", result); |
1446 | return result; |
1447 | |
1448 | error_just_free: |
1449 | up_write(&nommu_region_sem); |
1450 | error: |
1451 | if (region->vm_file) |
1452 | fput(region->vm_file); |
1453 | kmem_cache_free(vm_region_jar, region); |
1454 | if (vma->vm_file) |
1455 | fput(vma->vm_file); |
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(0); |
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(0); |
1479 | return -ENOMEM; |
1480 | } |
1481 | |
1482 | SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, |
1483 | unsigned long, prot, unsigned long, flags, |
1484 | unsigned long, fd, unsigned long, pgoff) |
1485 | { |
1486 | struct file *file = NULL; |
1487 | unsigned long retval = -EBADF; |
1488 | |
1489 | audit_mmap_fd(fd, flags); |
1490 | if (!(flags & MAP_ANONYMOUS)) { |
1491 | file = fget(fd); |
1492 | if (!file) |
1493 | goto out; |
1494 | } |
1495 | |
1496 | flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); |
1497 | |
1498 | retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); |
1499 | |
1500 | if (file) |
1501 | fput(file); |
1502 | out: |
1503 | return retval; |
1504 | } |
1505 | |
1506 | #ifdef __ARCH_WANT_SYS_OLD_MMAP |
1507 | struct mmap_arg_struct { |
1508 | unsigned long addr; |
1509 | unsigned long len; |
1510 | unsigned long prot; |
1511 | unsigned long flags; |
1512 | unsigned long fd; |
1513 | unsigned long offset; |
1514 | }; |
1515 | |
1516 | SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) |
1517 | { |
1518 | struct mmap_arg_struct a; |
1519 | |
1520 | if (copy_from_user(&a, arg, sizeof(a))) |
1521 | return -EFAULT; |
1522 | if (a.offset & ~PAGE_MASK) |
1523 | return -EINVAL; |
1524 | |
1525 | return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, |
1526 | a.offset >> PAGE_SHIFT); |
1527 | } |
1528 | #endif /* __ARCH_WANT_SYS_OLD_MMAP */ |
1529 | |
1530 | /* |
1531 | * split a vma into two pieces at address 'addr', a new vma is allocated either |
1532 | * for the first part or the tail. |
1533 | */ |
1534 | int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, |
1535 | unsigned long addr, int new_below) |
1536 | { |
1537 | struct vm_area_struct *new; |
1538 | struct vm_region *region; |
1539 | unsigned long npages; |
1540 | |
1541 | kenter(""); |
1542 | |
1543 | /* we're only permitted to split anonymous regions (these should have |
1544 | * only a single usage on the region) */ |
1545 | if (vma->vm_file) |
1546 | return -ENOMEM; |
1547 | |
1548 | if (mm->map_count >= sysctl_max_map_count) |
1549 | return -ENOMEM; |
1550 | |
1551 | region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL); |
1552 | if (!region) |
1553 | return -ENOMEM; |
1554 | |
1555 | new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); |
1556 | if (!new) { |
1557 | kmem_cache_free(vm_region_jar, region); |
1558 | return -ENOMEM; |
1559 | } |
1560 | |
1561 | /* most fields are the same, copy all, and then fixup */ |
1562 | *new = *vma; |
1563 | *region = *vma->vm_region; |
1564 | new->vm_region = region; |
1565 | |
1566 | npages = (addr - vma->vm_start) >> PAGE_SHIFT; |
1567 | |
1568 | if (new_below) { |
1569 | region->vm_top = region->vm_end = new->vm_end = addr; |
1570 | } else { |
1571 | region->vm_start = new->vm_start = addr; |
1572 | region->vm_pgoff = new->vm_pgoff += npages; |
1573 | } |
1574 | |
1575 | if (new->vm_ops && new->vm_ops->open) |
1576 | new->vm_ops->open(new); |
1577 | |
1578 | delete_vma_from_mm(vma); |
1579 | down_write(&nommu_region_sem); |
1580 | delete_nommu_region(vma->vm_region); |
1581 | if (new_below) { |
1582 | vma->vm_region->vm_start = vma->vm_start = addr; |
1583 | vma->vm_region->vm_pgoff = vma->vm_pgoff += npages; |
1584 | } else { |
1585 | vma->vm_region->vm_end = vma->vm_end = addr; |
1586 | vma->vm_region->vm_top = addr; |
1587 | } |
1588 | add_nommu_region(vma->vm_region); |
1589 | add_nommu_region(new->vm_region); |
1590 | up_write(&nommu_region_sem); |
1591 | add_vma_to_mm(mm, vma); |
1592 | add_vma_to_mm(mm, new); |
1593 | return 0; |
1594 | } |
1595 | |
1596 | /* |
1597 | * shrink a VMA by removing the specified chunk from either the beginning or |
1598 | * the end |
1599 | */ |
1600 | static int shrink_vma(struct mm_struct *mm, |
1601 | struct vm_area_struct *vma, |
1602 | unsigned long from, unsigned long to) |
1603 | { |
1604 | struct vm_region *region; |
1605 | |
1606 | kenter(""); |
1607 | |
1608 | /* adjust the VMA's pointers, which may reposition it in the MM's tree |
1609 | * and list */ |
1610 | delete_vma_from_mm(vma); |
1611 | if (from > vma->vm_start) |
1612 | vma->vm_end = from; |
1613 | else |
1614 | vma->vm_start = to; |
1615 | add_vma_to_mm(mm, vma); |
1616 | |
1617 | /* cut the backing region down to size */ |
1618 | region = vma->vm_region; |
1619 | BUG_ON(region->vm_usage != 1); |
1620 | |
1621 | down_write(&nommu_region_sem); |
1622 | delete_nommu_region(region); |
1623 | if (from > region->vm_start) { |
1624 | to = region->vm_top; |
1625 | region->vm_top = region->vm_end = from; |
1626 | } else { |
1627 | region->vm_start = to; |
1628 | } |
1629 | add_nommu_region(region); |
1630 | up_write(&nommu_region_sem); |
1631 | |
1632 | free_page_series(from, to); |
1633 | return 0; |
1634 | } |
1635 | |
1636 | /* |
1637 | * release a mapping |
1638 | * - under NOMMU conditions the chunk to be unmapped must be backed by a single |
1639 | * VMA, though it need not cover the whole VMA |
1640 | */ |
1641 | int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) |
1642 | { |
1643 | struct vm_area_struct *vma; |
1644 | unsigned long end; |
1645 | int ret; |
1646 | |
1647 | kenter(",%lx,%zx", start, len); |
1648 | |
1649 | len = PAGE_ALIGN(len); |
1650 | if (len == 0) |
1651 | return -EINVAL; |
1652 | |
1653 | end = start + len; |
1654 | |
1655 | /* find the first potentially overlapping VMA */ |
1656 | vma = find_vma(mm, start); |
1657 | if (!vma) { |
1658 | static int limit = 0; |
1659 | if (limit < 5) { |
1660 | printk(KERN_WARNING |
1661 | "munmap of memory not mmapped by process %d" |
1662 | " (%s): 0x%lx-0x%lx\n", |
1663 | current->pid, current->comm, |
1664 | start, start + len - 1); |
1665 | limit++; |
1666 | } |
1667 | return -EINVAL; |
1668 | } |
1669 | |
1670 | /* we're allowed to split an anonymous VMA but not a file-backed one */ |
1671 | if (vma->vm_file) { |
1672 | do { |
1673 | if (start > vma->vm_start) { |
1674 | kleave(" = -EINVAL [miss]"); |
1675 | return -EINVAL; |
1676 | } |
1677 | if (end == vma->vm_end) |
1678 | goto erase_whole_vma; |
1679 | vma = vma->vm_next; |
1680 | } while (vma); |
1681 | kleave(" = -EINVAL [split file]"); |
1682 | return -EINVAL; |
1683 | } else { |
1684 | /* the chunk must be a subset of the VMA found */ |
1685 | if (start == vma->vm_start && end == vma->vm_end) |
1686 | goto erase_whole_vma; |
1687 | if (start < vma->vm_start || end > vma->vm_end) { |
1688 | kleave(" = -EINVAL [superset]"); |
1689 | return -EINVAL; |
1690 | } |
1691 | if (start & ~PAGE_MASK) { |
1692 | kleave(" = -EINVAL [unaligned start]"); |
1693 | return -EINVAL; |
1694 | } |
1695 | if (end != vma->vm_end && end & ~PAGE_MASK) { |
1696 | kleave(" = -EINVAL [unaligned split]"); |
1697 | return -EINVAL; |
1698 | } |
1699 | if (start != vma->vm_start && end != vma->vm_end) { |
1700 | ret = split_vma(mm, vma, start, 1); |
1701 | if (ret < 0) { |
1702 | kleave(" = %d [split]", ret); |
1703 | return ret; |
1704 | } |
1705 | } |
1706 | return shrink_vma(mm, vma, start, end); |
1707 | } |
1708 | |
1709 | erase_whole_vma: |
1710 | delete_vma_from_mm(vma); |
1711 | delete_vma(mm, vma); |
1712 | kleave(" = 0"); |
1713 | return 0; |
1714 | } |
1715 | EXPORT_SYMBOL(do_munmap); |
1716 | |
1717 | int vm_munmap(unsigned long addr, size_t len) |
1718 | { |
1719 | struct mm_struct *mm = current->mm; |
1720 | int ret; |
1721 | |
1722 | down_write(&mm->mmap_sem); |
1723 | ret = do_munmap(mm, addr, len); |
1724 | up_write(&mm->mmap_sem); |
1725 | return ret; |
1726 | } |
1727 | EXPORT_SYMBOL(vm_munmap); |
1728 | |
1729 | SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) |
1730 | { |
1731 | return vm_munmap(addr, len); |
1732 | } |
1733 | |
1734 | /* |
1735 | * release all the mappings made in a process's VM space |
1736 | */ |
1737 | void exit_mmap(struct mm_struct *mm) |
1738 | { |
1739 | struct vm_area_struct *vma; |
1740 | |
1741 | if (!mm) |
1742 | return; |
1743 | |
1744 | kenter(""); |
1745 | |
1746 | mm->total_vm = 0; |
1747 | |
1748 | while ((vma = mm->mmap)) { |
1749 | mm->mmap = vma->vm_next; |
1750 | delete_vma_from_mm(vma); |
1751 | delete_vma(mm, vma); |
1752 | cond_resched(); |
1753 | } |
1754 | |
1755 | kleave(""); |
1756 | } |
1757 | |
1758 | unsigned long vm_brk(unsigned long addr, unsigned long len) |
1759 | { |
1760 | return -ENOMEM; |
1761 | } |
1762 | |
1763 | /* |
1764 | * expand (or shrink) an existing mapping, potentially moving it at the same |
1765 | * time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
1766 | * |
1767 | * under NOMMU conditions, we only permit changing a mapping's size, and only |
1768 | * as long as it stays within the region allocated by do_mmap_private() and the |
1769 | * block is not shareable |
1770 | * |
1771 | * MREMAP_FIXED is not supported under NOMMU conditions |
1772 | */ |
1773 | unsigned long do_mremap(unsigned long addr, |
1774 | unsigned long old_len, unsigned long new_len, |
1775 | unsigned long flags, unsigned long new_addr) |
1776 | { |
1777 | struct vm_area_struct *vma; |
1778 | |
1779 | /* insanity checks first */ |
1780 | old_len = PAGE_ALIGN(old_len); |
1781 | new_len = PAGE_ALIGN(new_len); |
1782 | if (old_len == 0 || new_len == 0) |
1783 | return (unsigned long) -EINVAL; |
1784 | |
1785 | if (addr & ~PAGE_MASK) |
1786 | return -EINVAL; |
1787 | |
1788 | if (flags & MREMAP_FIXED && new_addr != addr) |
1789 | return (unsigned long) -EINVAL; |
1790 | |
1791 | vma = find_vma_exact(current->mm, addr, old_len); |
1792 | if (!vma) |
1793 | return (unsigned long) -EINVAL; |
1794 | |
1795 | if (vma->vm_end != vma->vm_start + old_len) |
1796 | return (unsigned long) -EFAULT; |
1797 | |
1798 | if (vma->vm_flags & VM_MAYSHARE) |
1799 | return (unsigned long) -EPERM; |
1800 | |
1801 | if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start) |
1802 | return (unsigned long) -ENOMEM; |
1803 | |
1804 | /* all checks complete - do it */ |
1805 | vma->vm_end = vma->vm_start + new_len; |
1806 | return vma->vm_start; |
1807 | } |
1808 | EXPORT_SYMBOL(do_mremap); |
1809 | |
1810 | SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, |
1811 | unsigned long, new_len, unsigned long, flags, |
1812 | unsigned long, new_addr) |
1813 | { |
1814 | unsigned long ret; |
1815 | |
1816 | down_write(¤t->mm->mmap_sem); |
1817 | ret = do_mremap(addr, old_len, new_len, flags, new_addr); |
1818 | up_write(¤t->mm->mmap_sem); |
1819 | return ret; |
1820 | } |
1821 | |
1822 | struct page *follow_page_mask(struct vm_area_struct *vma, |
1823 | unsigned long address, unsigned int flags, |
1824 | unsigned int *page_mask) |
1825 | { |
1826 | *page_mask = 0; |
1827 | return NULL; |
1828 | } |
1829 | |
1830 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
1831 | unsigned long pfn, unsigned long size, pgprot_t prot) |
1832 | { |
1833 | if (addr != (pfn << PAGE_SHIFT)) |
1834 | return -EINVAL; |
1835 | |
1836 | vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; |
1837 | return 0; |
1838 | } |
1839 | EXPORT_SYMBOL(remap_pfn_range); |
1840 | |
1841 | int remap_vmalloc_range(struct vm_area_struct *vma, void *addr, |
1842 | unsigned long pgoff) |
1843 | { |
1844 | unsigned int size = vma->vm_end - vma->vm_start; |
1845 | |
1846 | if (!(vma->vm_flags & VM_USERMAP)) |
1847 | return -EINVAL; |
1848 | |
1849 | vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT)); |
1850 | vma->vm_end = vma->vm_start + size; |
1851 | |
1852 | return 0; |
1853 | } |
1854 | EXPORT_SYMBOL(remap_vmalloc_range); |
1855 | |
1856 | unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr, |
1857 | unsigned long len, unsigned long pgoff, unsigned long flags) |
1858 | { |
1859 | return -ENOMEM; |
1860 | } |
1861 | |
1862 | void arch_unmap_area(struct mm_struct *mm, unsigned long addr) |
1863 | { |
1864 | } |
1865 | |
1866 | void unmap_mapping_range(struct address_space *mapping, |
1867 | loff_t const holebegin, loff_t const holelen, |
1868 | int even_cows) |
1869 | { |
1870 | } |
1871 | EXPORT_SYMBOL(unmap_mapping_range); |
1872 | |
1873 | /* |
1874 | * Check that a process has enough memory to allocate a new virtual |
1875 | * mapping. 0 means there is enough memory for the allocation to |
1876 | * succeed and -ENOMEM implies there is not. |
1877 | * |
1878 | * We currently support three overcommit policies, which are set via the |
1879 | * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting |
1880 | * |
1881 | * Strict overcommit modes added 2002 Feb 26 by Alan Cox. |
1882 | * Additional code 2002 Jul 20 by Robert Love. |
1883 | * |
1884 | * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. |
1885 | * |
1886 | * Note this is a helper function intended to be used by LSMs which |
1887 | * wish to use this logic. |
1888 | */ |
1889 | int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) |
1890 | { |
1891 | unsigned long free, allowed; |
1892 | |
1893 | vm_acct_memory(pages); |
1894 | |
1895 | /* |
1896 | * Sometimes we want to use more memory than we have |
1897 | */ |
1898 | if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) |
1899 | return 0; |
1900 | |
1901 | if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
1902 | free = global_page_state(NR_FREE_PAGES); |
1903 | free += global_page_state(NR_FILE_PAGES); |
1904 | |
1905 | /* |
1906 | * shmem pages shouldn't be counted as free in this |
1907 | * case, they can't be purged, only swapped out, and |
1908 | * that won't affect the overall amount of available |
1909 | * memory in the system. |
1910 | */ |
1911 | free -= global_page_state(NR_SHMEM); |
1912 | |
1913 | free += get_nr_swap_pages(); |
1914 | |
1915 | /* |
1916 | * Any slabs which are created with the |
1917 | * SLAB_RECLAIM_ACCOUNT flag claim to have contents |
1918 | * which are reclaimable, under pressure. The dentry |
1919 | * cache and most inode caches should fall into this |
1920 | */ |
1921 | free += global_page_state(NR_SLAB_RECLAIMABLE); |
1922 | |
1923 | /* |
1924 | * Leave reserved pages. The pages are not for anonymous pages. |
1925 | */ |
1926 | if (free <= totalreserve_pages) |
1927 | goto error; |
1928 | else |
1929 | free -= totalreserve_pages; |
1930 | |
1931 | /* |
1932 | * Leave the last 3% for root |
1933 | */ |
1934 | if (!cap_sys_admin) |
1935 | free -= free / 32; |
1936 | |
1937 | if (free > pages) |
1938 | return 0; |
1939 | |
1940 | goto error; |
1941 | } |
1942 | |
1943 | allowed = totalram_pages * sysctl_overcommit_ratio / 100; |
1944 | /* |
1945 | * Leave the last 3% for root |
1946 | */ |
1947 | if (!cap_sys_admin) |
1948 | allowed -= allowed / 32; |
1949 | allowed += total_swap_pages; |
1950 | |
1951 | /* Don't let a single process grow too big: |
1952 | leave 3% of the size of this process for other processes */ |
1953 | if (mm) |
1954 | allowed -= mm->total_vm / 32; |
1955 | |
1956 | if (percpu_counter_read_positive(&vm_committed_as) < allowed) |
1957 | return 0; |
1958 | |
1959 | error: |
1960 | vm_unacct_memory(pages); |
1961 | |
1962 | return -ENOMEM; |
1963 | } |
1964 | |
1965 | int in_gate_area_no_mm(unsigned long addr) |
1966 | { |
1967 | return 0; |
1968 | } |
1969 | |
1970 | int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
1971 | { |
1972 | BUG(); |
1973 | return 0; |
1974 | } |
1975 | EXPORT_SYMBOL(filemap_fault); |
1976 | |
1977 | int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr, |
1978 | unsigned long size, pgoff_t pgoff) |
1979 | { |
1980 | BUG(); |
1981 | return 0; |
1982 | } |
1983 | EXPORT_SYMBOL(generic_file_remap_pages); |
1984 | |
1985 | static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, |
1986 | unsigned long addr, void *buf, int len, int write) |
1987 | { |
1988 | struct vm_area_struct *vma; |
1989 | |
1990 | down_read(&mm->mmap_sem); |
1991 | |
1992 | /* the access must start within one of the target process's mappings */ |
1993 | vma = find_vma(mm, addr); |
1994 | if (vma) { |
1995 | /* don't overrun this mapping */ |
1996 | if (addr + len >= vma->vm_end) |
1997 | len = vma->vm_end - addr; |
1998 | |
1999 | /* only read or write mappings where it is permitted */ |
2000 | if (write && vma->vm_flags & VM_MAYWRITE) |
2001 | copy_to_user_page(vma, NULL, addr, |
2002 | (void *) addr, buf, len); |
2003 | else if (!write && vma->vm_flags & VM_MAYREAD) |
2004 | copy_from_user_page(vma, NULL, addr, |
2005 | buf, (void *) addr, len); |
2006 | else |
2007 | len = 0; |
2008 | } else { |
2009 | len = 0; |
2010 | } |
2011 | |
2012 | up_read(&mm->mmap_sem); |
2013 | |
2014 | return len; |
2015 | } |
2016 | |
2017 | /** |
2018 | * @access_remote_vm - access another process' address space |
2019 | * @mm: the mm_struct of the target address space |
2020 | * @addr: start address to access |
2021 | * @buf: source or destination buffer |
2022 | * @len: number of bytes to transfer |
2023 | * @write: whether the access is a write |
2024 | * |
2025 | * The caller must hold a reference on @mm. |
2026 | */ |
2027 | int access_remote_vm(struct mm_struct *mm, unsigned long addr, |
2028 | void *buf, int len, int write) |
2029 | { |
2030 | return __access_remote_vm(NULL, mm, addr, buf, len, write); |
2031 | } |
2032 | |
2033 | /* |
2034 | * Access another process' address space. |
2035 | * - source/target buffer must be kernel space |
2036 | */ |
2037 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) |
2038 | { |
2039 | struct mm_struct *mm; |
2040 | |
2041 | if (addr + len < addr) |
2042 | return 0; |
2043 | |
2044 | mm = get_task_mm(tsk); |
2045 | if (!mm) |
2046 | return 0; |
2047 | |
2048 | len = __access_remote_vm(tsk, mm, addr, buf, len, write); |
2049 | |
2050 | mmput(mm); |
2051 | return len; |
2052 | } |
2053 | |
2054 | /** |
2055 | * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode |
2056 | * @inode: The inode to check |
2057 | * @size: The current filesize of the inode |
2058 | * @newsize: The proposed filesize of the inode |
2059 | * |
2060 | * Check the shared mappings on an inode on behalf of a shrinking truncate to |
2061 | * make sure that that any outstanding VMAs aren't broken and then shrink the |
2062 | * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't |
2063 | * automatically grant mappings that are too large. |
2064 | */ |
2065 | int nommu_shrink_inode_mappings(struct inode *inode, size_t size, |
2066 | size_t newsize) |
2067 | { |
2068 | struct vm_area_struct *vma; |
2069 | struct vm_region *region; |
2070 | pgoff_t low, high; |
2071 | size_t r_size, r_top; |
2072 | |
2073 | low = newsize >> PAGE_SHIFT; |
2074 | high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; |
2075 | |
2076 | down_write(&nommu_region_sem); |
2077 | mutex_lock(&inode->i_mapping->i_mmap_mutex); |
2078 | |
2079 | /* search for VMAs that fall within the dead zone */ |
2080 | vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) { |
2081 | /* found one - only interested if it's shared out of the page |
2082 | * cache */ |
2083 | if (vma->vm_flags & VM_SHARED) { |
2084 | mutex_unlock(&inode->i_mapping->i_mmap_mutex); |
2085 | up_write(&nommu_region_sem); |
2086 | return -ETXTBSY; /* not quite true, but near enough */ |
2087 | } |
2088 | } |
2089 | |
2090 | /* reduce any regions that overlap the dead zone - if in existence, |
2091 | * these will be pointed to by VMAs that don't overlap the dead zone |
2092 | * |
2093 | * we don't check for any regions that start beyond the EOF as there |
2094 | * shouldn't be any |
2095 | */ |
2096 | vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, |
2097 | 0, ULONG_MAX) { |
2098 | if (!(vma->vm_flags & VM_SHARED)) |
2099 | continue; |
2100 | |
2101 | region = vma->vm_region; |
2102 | r_size = region->vm_top - region->vm_start; |
2103 | r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size; |
2104 | |
2105 | if (r_top > newsize) { |
2106 | region->vm_top -= r_top - newsize; |
2107 | if (region->vm_end > region->vm_top) |
2108 | region->vm_end = region->vm_top; |
2109 | } |
2110 | } |
2111 | |
2112 | mutex_unlock(&inode->i_mapping->i_mmap_mutex); |
2113 | up_write(&nommu_region_sem); |
2114 | return 0; |
2115 | } |
2116 |
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