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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * linux/mm/nommu.c
4 *
5 * Replacement code for mm functions to support CPU's that don't
6 * have any form of memory management unit (thus no virtual memory).
7 *
8 * See Documentation/admin-guide/mm/nommu-mmap.rst
9 *
10 * Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
11 * Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
12 * Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
13 * Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
14 * Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
15 */
16
17#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
18
19#include <linux/export.h>
20#include <linux/mm.h>
21#include <linux/sched/mm.h>
22#include <linux/vmacache.h>
23#include <linux/mman.h>
24#include <linux/swap.h>
25#include <linux/file.h>
26#include <linux/highmem.h>
27#include <linux/pagemap.h>
28#include <linux/slab.h>
29#include <linux/vmalloc.h>
30#include <linux/blkdev.h>
31#include <linux/backing-dev.h>
32#include <linux/compiler.h>
33#include <linux/mount.h>
34#include <linux/personality.h>
35#include <linux/security.h>
36#include <linux/syscalls.h>
37#include <linux/audit.h>
38#include <linux/printk.h>
39
40#include <linux/uaccess.h>
41#include <asm/tlb.h>
42#include <asm/tlbflush.h>
43#include <asm/mmu_context.h>
44#include "internal.h"
45
46void *high_memory;
47EXPORT_SYMBOL(high_memory);
48struct page *mem_map;
49unsigned long max_mapnr;
50EXPORT_SYMBOL(max_mapnr);
51unsigned long highest_memmap_pfn;
52int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
53int heap_stack_gap = 0;
54
55atomic_long_t mmap_pages_allocated;
56
57EXPORT_SYMBOL(mem_map);
58
59/* list of mapped, potentially shareable regions */
60static struct kmem_cache *vm_region_jar;
61struct rb_root nommu_region_tree = RB_ROOT;
62DECLARE_RWSEM(nommu_region_sem);
63
64const struct vm_operations_struct generic_file_vm_ops = {
65};
66
67/*
68 * Return the total memory allocated for this pointer, not
69 * just what the caller asked for.
70 *
71 * Doesn't have to be accurate, i.e. may have races.
72 */
73unsigned int kobjsize(const void *objp)
74{
75 struct page *page;
76
77 /*
78 * If the object we have should not have ksize performed on it,
79 * return size of 0
80 */
81 if (!objp || !virt_addr_valid(objp))
82 return 0;
83
84 page = virt_to_head_page(objp);
85
86 /*
87 * If the allocator sets PageSlab, we know the pointer came from
88 * kmalloc().
89 */
90 if (PageSlab(page))
91 return ksize(objp);
92
93 /*
94 * If it's not a compound page, see if we have a matching VMA
95 * region. This test is intentionally done in reverse order,
96 * so if there's no VMA, we still fall through and hand back
97 * PAGE_SIZE for 0-order pages.
98 */
99 if (!PageCompound(page)) {
100 struct vm_area_struct *vma;
101
102 vma = find_vma(current->mm, (unsigned long)objp);
103 if (vma)
104 return vma->vm_end - vma->vm_start;
105 }
106
107 /*
108 * The ksize() function is only guaranteed to work for pointers
109 * returned by kmalloc(). So handle arbitrary pointers here.
110 */
111 return page_size(page);
112}
113
114/**
115 * follow_pfn - look up PFN at a user virtual address
116 * @vma: memory mapping
117 * @address: user virtual address
118 * @pfn: location to store found PFN
119 *
120 * Only IO mappings and raw PFN mappings are allowed.
121 *
122 * Returns zero and the pfn at @pfn on success, -ve otherwise.
123 */
124int follow_pfn(struct vm_area_struct *vma, unsigned long address,
125 unsigned long *pfn)
126{
127 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
128 return -EINVAL;
129
130 *pfn = address >> PAGE_SHIFT;
131 return 0;
132}
133EXPORT_SYMBOL(follow_pfn);
134
135LIST_HEAD(vmap_area_list);
136
137void vfree(const void *addr)
138{
139 kfree(addr);
140}
141EXPORT_SYMBOL(vfree);
142
143void *__vmalloc(unsigned long size, gfp_t gfp_mask)
144{
145 /*
146 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
147 * returns only a logical address.
148 */
149 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
150}
151EXPORT_SYMBOL(__vmalloc);
152
153void *__vmalloc_node_range(unsigned long size, unsigned long align,
154 unsigned long start, unsigned long end, gfp_t gfp_mask,
155 pgprot_t prot, unsigned long vm_flags, int node,
156 const void *caller)
157{
158 return __vmalloc(size, gfp_mask);
159}
160
161void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
162 int node, const void *caller)
163{
164 return __vmalloc(size, gfp_mask);
165}
166
167static void *__vmalloc_user_flags(unsigned long size, gfp_t flags)
168{
169 void *ret;
170
171 ret = __vmalloc(size, flags);
172 if (ret) {
173 struct vm_area_struct *vma;
174
175 mmap_write_lock(current->mm);
176 vma = find_vma(current->mm, (unsigned long)ret);
177 if (vma)
178 vma->vm_flags |= VM_USERMAP;
179 mmap_write_unlock(current->mm);
180 }
181
182 return ret;
183}
184
185void *vmalloc_user(unsigned long size)
186{
187 return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO);
188}
189EXPORT_SYMBOL(vmalloc_user);
190
191struct page *vmalloc_to_page(const void *addr)
192{
193 return virt_to_page(addr);
194}
195EXPORT_SYMBOL(vmalloc_to_page);
196
197unsigned long vmalloc_to_pfn(const void *addr)
198{
199 return page_to_pfn(virt_to_page(addr));
200}
201EXPORT_SYMBOL(vmalloc_to_pfn);
202
203long vread(char *buf, char *addr, unsigned long count)
204{
205 /* Don't allow overflow */
206 if ((unsigned long) buf + count < count)
207 count = -(unsigned long) buf;
208
209 memcpy(buf, addr, count);
210 return count;
211}
212
213/*
214 * vmalloc - allocate virtually contiguous memory
215 *
216 * @size: allocation size
217 *
218 * Allocate enough pages to cover @size from the page level
219 * allocator and map them into contiguous kernel virtual space.
220 *
221 * For tight control over page level allocator and protection flags
222 * use __vmalloc() instead.
223 */
224void *vmalloc(unsigned long size)
225{
226 return __vmalloc(size, GFP_KERNEL);
227}
228EXPORT_SYMBOL(vmalloc);
229
230/*
231 * vzalloc - allocate virtually contiguous memory with zero fill
232 *
233 * @size: allocation size
234 *
235 * Allocate enough pages to cover @size from the page level
236 * allocator and map them into contiguous kernel virtual space.
237 * The memory allocated is set to zero.
238 *
239 * For tight control over page level allocator and protection flags
240 * use __vmalloc() instead.
241 */
242void *vzalloc(unsigned long size)
243{
244 return __vmalloc(size, GFP_KERNEL | __GFP_ZERO);
245}
246EXPORT_SYMBOL(vzalloc);
247
248/**
249 * vmalloc_node - allocate memory on a specific node
250 * @size: allocation size
251 * @node: numa node
252 *
253 * Allocate enough pages to cover @size from the page level
254 * allocator and map them into contiguous kernel virtual space.
255 *
256 * For tight control over page level allocator and protection flags
257 * use __vmalloc() instead.
258 */
259void *vmalloc_node(unsigned long size, int node)
260{
261 return vmalloc(size);
262}
263EXPORT_SYMBOL(vmalloc_node);
264
265/**
266 * vzalloc_node - allocate memory on a specific node with zero fill
267 * @size: allocation size
268 * @node: numa node
269 *
270 * Allocate enough pages to cover @size from the page level
271 * allocator and map them into contiguous kernel virtual space.
272 * The memory allocated is set to zero.
273 *
274 * For tight control over page level allocator and protection flags
275 * use __vmalloc() instead.
276 */
277void *vzalloc_node(unsigned long size, int node)
278{
279 return vzalloc(size);
280}
281EXPORT_SYMBOL(vzalloc_node);
282
283/**
284 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
285 * @size: allocation size
286 *
287 * Allocate enough 32bit PA addressable pages to cover @size from the
288 * page level allocator and map them into contiguous kernel virtual space.
289 */
290void *vmalloc_32(unsigned long size)
291{
292 return __vmalloc(size, GFP_KERNEL);
293}
294EXPORT_SYMBOL(vmalloc_32);
295
296/**
297 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
298 * @size: allocation size
299 *
300 * The resulting memory area is 32bit addressable and zeroed so it can be
301 * mapped to userspace without leaking data.
302 *
303 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
304 * remap_vmalloc_range() are permissible.
305 */
306void *vmalloc_32_user(unsigned long size)
307{
308 /*
309 * We'll have to sort out the ZONE_DMA bits for 64-bit,
310 * but for now this can simply use vmalloc_user() directly.
311 */
312 return vmalloc_user(size);
313}
314EXPORT_SYMBOL(vmalloc_32_user);
315
316void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
317{
318 BUG();
319 return NULL;
320}
321EXPORT_SYMBOL(vmap);
322
323void vunmap(const void *addr)
324{
325 BUG();
326}
327EXPORT_SYMBOL(vunmap);
328
329void *vm_map_ram(struct page **pages, unsigned int count, int node)
330{
331 BUG();
332 return NULL;
333}
334EXPORT_SYMBOL(vm_map_ram);
335
336void vm_unmap_ram(const void *mem, unsigned int count)
337{
338 BUG();
339}
340EXPORT_SYMBOL(vm_unmap_ram);
341
342void vm_unmap_aliases(void)
343{
344}
345EXPORT_SYMBOL_GPL(vm_unmap_aliases);
346
347void free_vm_area(struct vm_struct *area)
348{
349 BUG();
350}
351EXPORT_SYMBOL_GPL(free_vm_area);
352
353int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
354 struct page *page)
355{
356 return -EINVAL;
357}
358EXPORT_SYMBOL(vm_insert_page);
359
360int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
361 unsigned long num)
362{
363 return -EINVAL;
364}
365EXPORT_SYMBOL(vm_map_pages);
366
367int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
368 unsigned long num)
369{
370 return -EINVAL;
371}
372EXPORT_SYMBOL(vm_map_pages_zero);
373
374/*
375 * sys_brk() for the most part doesn't need the global kernel
376 * lock, except when an application is doing something nasty
377 * like trying to un-brk an area that has already been mapped
378 * to a regular file. in this case, the unmapping will need
379 * to invoke file system routines that need the global lock.
380 */
381SYSCALL_DEFINE1(brk, unsigned long, brk)
382{
383 struct mm_struct *mm = current->mm;
384
385 if (brk < mm->start_brk || brk > mm->context.end_brk)
386 return mm->brk;
387
388 if (mm->brk == brk)
389 return mm->brk;
390
391 /*
392 * Always allow shrinking brk
393 */
394 if (brk <= mm->brk) {
395 mm->brk = brk;
396 return brk;
397 }
398
399 /*
400 * Ok, looks good - let it rip.
401 */
402 flush_icache_user_range(mm->brk, brk);
403 return mm->brk = brk;
404}
405
406/*
407 * initialise the percpu counter for VM and region record slabs
408 */
409void __init mmap_init(void)
410{
411 int ret;
412
413 ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
414 VM_BUG_ON(ret);
415 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
416}
417
418/*
419 * validate the region tree
420 * - the caller must hold the region lock
421 */
422#ifdef CONFIG_DEBUG_NOMMU_REGIONS
423static noinline void validate_nommu_regions(void)
424{
425 struct vm_region *region, *last;
426 struct rb_node *p, *lastp;
427
428 lastp = rb_first(&nommu_region_tree);
429 if (!lastp)
430 return;
431
432 last = rb_entry(lastp, struct vm_region, vm_rb);
433 BUG_ON(last->vm_end <= last->vm_start);
434 BUG_ON(last->vm_top < last->vm_end);
435
436 while ((p = rb_next(lastp))) {
437 region = rb_entry(p, struct vm_region, vm_rb);
438 last = rb_entry(lastp, struct vm_region, vm_rb);
439
440 BUG_ON(region->vm_end <= region->vm_start);
441 BUG_ON(region->vm_top < region->vm_end);
442 BUG_ON(region->vm_start < last->vm_top);
443
444 lastp = p;
445 }
446}
447#else
448static void validate_nommu_regions(void)
449{
450}
451#endif
452
453/*
454 * add a region into the global tree
455 */
456static void add_nommu_region(struct vm_region *region)
457{
458 struct vm_region *pregion;
459 struct rb_node **p, *parent;
460
461 validate_nommu_regions();
462
463 parent = NULL;
464 p = &nommu_region_tree.rb_node;
465 while (*p) {
466 parent = *p;
467 pregion = rb_entry(parent, struct vm_region, vm_rb);
468 if (region->vm_start < pregion->vm_start)
469 p = &(*p)->rb_left;
470 else if (region->vm_start > pregion->vm_start)
471 p = &(*p)->rb_right;
472 else if (pregion == region)
473 return;
474 else
475 BUG();
476 }
477
478 rb_link_node(®ion->vm_rb, parent, p);
479 rb_insert_color(®ion->vm_rb, &nommu_region_tree);
480
481 validate_nommu_regions();
482}
483
484/*
485 * delete a region from the global tree
486 */
487static void delete_nommu_region(struct vm_region *region)
488{
489 BUG_ON(!nommu_region_tree.rb_node);
490
491 validate_nommu_regions();
492 rb_erase(®ion->vm_rb, &nommu_region_tree);
493 validate_nommu_regions();
494}
495
496/*
497 * free a contiguous series of pages
498 */
499static void free_page_series(unsigned long from, unsigned long to)
500{
501 for (; from < to; from += PAGE_SIZE) {
502 struct page *page = virt_to_page(from);
503
504 atomic_long_dec(&mmap_pages_allocated);
505 put_page(page);
506 }
507}
508
509/*
510 * release a reference to a region
511 * - the caller must hold the region semaphore for writing, which this releases
512 * - the region may not have been added to the tree yet, in which case vm_top
513 * will equal vm_start
514 */
515static void __put_nommu_region(struct vm_region *region)
516 __releases(nommu_region_sem)
517{
518 BUG_ON(!nommu_region_tree.rb_node);
519
520 if (--region->vm_usage == 0) {
521 if (region->vm_top > region->vm_start)
522 delete_nommu_region(region);
523 up_write(&nommu_region_sem);
524
525 if (region->vm_file)
526 fput(region->vm_file);
527
528 /* IO memory and memory shared directly out of the pagecache
529 * from ramfs/tmpfs mustn't be released here */
530 if (region->vm_flags & VM_MAPPED_COPY)
531 free_page_series(region->vm_start, region->vm_top);
532 kmem_cache_free(vm_region_jar, region);
533 } else {
534 up_write(&nommu_region_sem);
535 }
536}
537
538/*
539 * release a reference to a region
540 */
541static void put_nommu_region(struct vm_region *region)
542{
543 down_write(&nommu_region_sem);
544 __put_nommu_region(region);
545}
546
547/*
548 * add a VMA into a process's mm_struct in the appropriate place in the list
549 * and tree and add to the address space's page tree also if not an anonymous
550 * page
551 * - should be called with mm->mmap_lock held writelocked
552 */
553static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
554{
555 struct vm_area_struct *pvma, *prev;
556 struct address_space *mapping;
557 struct rb_node **p, *parent, *rb_prev;
558
559 BUG_ON(!vma->vm_region);
560
561 mm->map_count++;
562 vma->vm_mm = mm;
563
564 /* add the VMA to the mapping */
565 if (vma->vm_file) {
566 mapping = vma->vm_file->f_mapping;
567
568 i_mmap_lock_write(mapping);
569 flush_dcache_mmap_lock(mapping);
570 vma_interval_tree_insert(vma, &mapping->i_mmap);
571 flush_dcache_mmap_unlock(mapping);
572 i_mmap_unlock_write(mapping);
573 }
574
575 /* add the VMA to the tree */
576 parent = rb_prev = NULL;
577 p = &mm->mm_rb.rb_node;
578 while (*p) {
579 parent = *p;
580 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
581
582 /* sort by: start addr, end addr, VMA struct addr in that order
583 * (the latter is necessary as we may get identical VMAs) */
584 if (vma->vm_start < pvma->vm_start)
585 p = &(*p)->rb_left;
586 else if (vma->vm_start > pvma->vm_start) {
587 rb_prev = parent;
588 p = &(*p)->rb_right;
589 } else if (vma->vm_end < pvma->vm_end)
590 p = &(*p)->rb_left;
591 else if (vma->vm_end > pvma->vm_end) {
592 rb_prev = parent;
593 p = &(*p)->rb_right;
594 } else if (vma < pvma)
595 p = &(*p)->rb_left;
596 else if (vma > pvma) {
597 rb_prev = parent;
598 p = &(*p)->rb_right;
599 } else
600 BUG();
601 }
602
603 rb_link_node(&vma->vm_rb, parent, p);
604 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
605
606 /* add VMA to the VMA list also */
607 prev = NULL;
608 if (rb_prev)
609 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
610
611 __vma_link_list(mm, vma, prev);
612}
613
614/*
615 * delete a VMA from its owning mm_struct and address space
616 */
617static void delete_vma_from_mm(struct vm_area_struct *vma)
618{
619 int i;
620 struct address_space *mapping;
621 struct mm_struct *mm = vma->vm_mm;
622 struct task_struct *curr = current;
623
624 mm->map_count--;
625 for (i = 0; i < VMACACHE_SIZE; i++) {
626 /* if the vma is cached, invalidate the entire cache */
627 if (curr->vmacache.vmas[i] == vma) {
628 vmacache_invalidate(mm);
629 break;
630 }
631 }
632
633 /* remove the VMA from the mapping */
634 if (vma->vm_file) {
635 mapping = vma->vm_file->f_mapping;
636
637 i_mmap_lock_write(mapping);
638 flush_dcache_mmap_lock(mapping);
639 vma_interval_tree_remove(vma, &mapping->i_mmap);
640 flush_dcache_mmap_unlock(mapping);
641 i_mmap_unlock_write(mapping);
642 }
643
644 /* remove from the MM's tree and list */
645 rb_erase(&vma->vm_rb, &mm->mm_rb);
646
647 __vma_unlink_list(mm, vma);
648}
649
650/*
651 * destroy a VMA record
652 */
653static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
654{
655 if (vma->vm_ops && vma->vm_ops->close)
656 vma->vm_ops->close(vma);
657 if (vma->vm_file)
658 fput(vma->vm_file);
659 put_nommu_region(vma->vm_region);
660 vm_area_free(vma);
661}
662
663/*
664 * look up the first VMA in which addr resides, NULL if none
665 * - should be called with mm->mmap_lock at least held readlocked
666 */
667struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
668{
669 struct vm_area_struct *vma;
670
671 /* check the cache first */
672 vma = vmacache_find(mm, addr);
673 if (likely(vma))
674 return vma;
675
676 /* trawl the list (there may be multiple mappings in which addr
677 * resides) */
678 for (vma = mm->mmap; vma; vma = vma->vm_next) {
679 if (vma->vm_start > addr)
680 return NULL;
681 if (vma->vm_end > addr) {
682 vmacache_update(addr, vma);
683 return vma;
684 }
685 }
686
687 return NULL;
688}
689EXPORT_SYMBOL(find_vma);
690
691/*
692 * find a VMA
693 * - we don't extend stack VMAs under NOMMU conditions
694 */
695struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
696{
697 return find_vma(mm, addr);
698}
699
700/*
701 * expand a stack to a given address
702 * - not supported under NOMMU conditions
703 */
704int expand_stack(struct vm_area_struct *vma, unsigned long address)
705{
706 return -ENOMEM;
707}
708
709/*
710 * look up the first VMA exactly that exactly matches addr
711 * - should be called with mm->mmap_lock at least held readlocked
712 */
713static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
714 unsigned long addr,
715 unsigned long len)
716{
717 struct vm_area_struct *vma;
718 unsigned long end = addr + len;
719
720 /* check the cache first */
721 vma = vmacache_find_exact(mm, addr, end);
722 if (vma)
723 return vma;
724
725 /* trawl the list (there may be multiple mappings in which addr
726 * resides) */
727 for (vma = mm->mmap; vma; vma = vma->vm_next) {
728 if (vma->vm_start < addr)
729 continue;
730 if (vma->vm_start > addr)
731 return NULL;
732 if (vma->vm_end == end) {
733 vmacache_update(addr, vma);
734 return vma;
735 }
736 }
737
738 return NULL;
739}
740
741/*
742 * determine whether a mapping should be permitted and, if so, what sort of
743 * mapping we're capable of supporting
744 */
745static int validate_mmap_request(struct file *file,
746 unsigned long addr,
747 unsigned long len,
748 unsigned long prot,
749 unsigned long flags,
750 unsigned long pgoff,
751 unsigned long *_capabilities)
752{
753 unsigned long capabilities, rlen;
754 int ret;
755
756 /* do the simple checks first */
757 if (flags & MAP_FIXED)
758 return -EINVAL;
759
760 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
761 (flags & MAP_TYPE) != MAP_SHARED)
762 return -EINVAL;
763
764 if (!len)
765 return -EINVAL;
766
767 /* Careful about overflows.. */
768 rlen = PAGE_ALIGN(len);
769 if (!rlen || rlen > TASK_SIZE)
770 return -ENOMEM;
771
772 /* offset overflow? */
773 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
774 return -EOVERFLOW;
775
776 if (file) {
777 /* files must support mmap */
778 if (!file->f_op->mmap)
779 return -ENODEV;
780
781 /* work out if what we've got could possibly be shared
782 * - we support chardevs that provide their own "memory"
783 * - we support files/blockdevs that are memory backed
784 */
785 if (file->f_op->mmap_capabilities) {
786 capabilities = file->f_op->mmap_capabilities(file);
787 } else {
788 /* no explicit capabilities set, so assume some
789 * defaults */
790 switch (file_inode(file)->i_mode & S_IFMT) {
791 case S_IFREG:
792 case S_IFBLK:
793 capabilities = NOMMU_MAP_COPY;
794 break;
795
796 case S_IFCHR:
797 capabilities =
798 NOMMU_MAP_DIRECT |
799 NOMMU_MAP_READ |
800 NOMMU_MAP_WRITE;
801 break;
802
803 default:
804 return -EINVAL;
805 }
806 }
807
808 /* eliminate any capabilities that we can't support on this
809 * device */
810 if (!file->f_op->get_unmapped_area)
811 capabilities &= ~NOMMU_MAP_DIRECT;
812 if (!(file->f_mode & FMODE_CAN_READ))
813 capabilities &= ~NOMMU_MAP_COPY;
814
815 /* The file shall have been opened with read permission. */
816 if (!(file->f_mode & FMODE_READ))
817 return -EACCES;
818
819 if (flags & MAP_SHARED) {
820 /* do checks for writing, appending and locking */
821 if ((prot & PROT_WRITE) &&
822 !(file->f_mode & FMODE_WRITE))
823 return -EACCES;
824
825 if (IS_APPEND(file_inode(file)) &&
826 (file->f_mode & FMODE_WRITE))
827 return -EACCES;
828
829 if (locks_verify_locked(file))
830 return -EAGAIN;
831
832 if (!(capabilities & NOMMU_MAP_DIRECT))
833 return -ENODEV;
834
835 /* we mustn't privatise shared mappings */
836 capabilities &= ~NOMMU_MAP_COPY;
837 } else {
838 /* we're going to read the file into private memory we
839 * allocate */
840 if (!(capabilities & NOMMU_MAP_COPY))
841 return -ENODEV;
842
843 /* we don't permit a private writable mapping to be
844 * shared with the backing device */
845 if (prot & PROT_WRITE)
846 capabilities &= ~NOMMU_MAP_DIRECT;
847 }
848
849 if (capabilities & NOMMU_MAP_DIRECT) {
850 if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
851 ((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
852 ((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
853 ) {
854 capabilities &= ~NOMMU_MAP_DIRECT;
855 if (flags & MAP_SHARED) {
856 pr_warn("MAP_SHARED not completely supported on !MMU\n");
857 return -EINVAL;
858 }
859 }
860 }
861
862 /* handle executable mappings and implied executable
863 * mappings */
864 if (path_noexec(&file->f_path)) {
865 if (prot & PROT_EXEC)
866 return -EPERM;
867 } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
868 /* handle implication of PROT_EXEC by PROT_READ */
869 if (current->personality & READ_IMPLIES_EXEC) {
870 if (capabilities & NOMMU_MAP_EXEC)
871 prot |= PROT_EXEC;
872 }
873 } else if ((prot & PROT_READ) &&
874 (prot & PROT_EXEC) &&
875 !(capabilities & NOMMU_MAP_EXEC)
876 ) {
877 /* backing file is not executable, try to copy */
878 capabilities &= ~NOMMU_MAP_DIRECT;
879 }
880 } else {
881 /* anonymous mappings are always memory backed and can be
882 * privately mapped
883 */
884 capabilities = NOMMU_MAP_COPY;
885
886 /* handle PROT_EXEC implication by PROT_READ */
887 if ((prot & PROT_READ) &&
888 (current->personality & READ_IMPLIES_EXEC))
889 prot |= PROT_EXEC;
890 }
891
892 /* allow the security API to have its say */
893 ret = security_mmap_addr(addr);
894 if (ret < 0)
895 return ret;
896
897 /* looks okay */
898 *_capabilities = capabilities;
899 return 0;
900}
901
902/*
903 * we've determined that we can make the mapping, now translate what we
904 * now know into VMA flags
905 */
906static unsigned long determine_vm_flags(struct file *file,
907 unsigned long prot,
908 unsigned long flags,
909 unsigned long capabilities)
910{
911 unsigned long vm_flags;
912
913 vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
914 /* vm_flags |= mm->def_flags; */
915
916 if (!(capabilities & NOMMU_MAP_DIRECT)) {
917 /* attempt to share read-only copies of mapped file chunks */
918 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
919 if (file && !(prot & PROT_WRITE))
920 vm_flags |= VM_MAYSHARE;
921 } else {
922 /* overlay a shareable mapping on the backing device or inode
923 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
924 * romfs/cramfs */
925 vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS);
926 if (flags & MAP_SHARED)
927 vm_flags |= VM_SHARED;
928 }
929
930 /* refuse to let anyone share private mappings with this process if
931 * it's being traced - otherwise breakpoints set in it may interfere
932 * with another untraced process
933 */
934 if ((flags & MAP_PRIVATE) && current->ptrace)
935 vm_flags &= ~VM_MAYSHARE;
936
937 return vm_flags;
938}
939
940/*
941 * set up a shared mapping on a file (the driver or filesystem provides and
942 * pins the storage)
943 */
944static int do_mmap_shared_file(struct vm_area_struct *vma)
945{
946 int ret;
947
948 ret = call_mmap(vma->vm_file, vma);
949 if (ret == 0) {
950 vma->vm_region->vm_top = vma->vm_region->vm_end;
951 return 0;
952 }
953 if (ret != -ENOSYS)
954 return ret;
955
956 /* getting -ENOSYS indicates that direct mmap isn't possible (as
957 * opposed to tried but failed) so we can only give a suitable error as
958 * it's not possible to make a private copy if MAP_SHARED was given */
959 return -ENODEV;
960}
961
962/*
963 * set up a private mapping or an anonymous shared mapping
964 */
965static int do_mmap_private(struct vm_area_struct *vma,
966 struct vm_region *region,
967 unsigned long len,
968 unsigned long capabilities)
969{
970 unsigned long total, point;
971 void *base;
972 int ret, order;
973
974 /* invoke the file's mapping function so that it can keep track of
975 * shared mappings on devices or memory
976 * - VM_MAYSHARE will be set if it may attempt to share
977 */
978 if (capabilities & NOMMU_MAP_DIRECT) {
979 ret = call_mmap(vma->vm_file, vma);
980 if (ret == 0) {
981 /* shouldn't return success if we're not sharing */
982 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
983 vma->vm_region->vm_top = vma->vm_region->vm_end;
984 return 0;
985 }
986 if (ret != -ENOSYS)
987 return ret;
988
989 /* getting an ENOSYS error indicates that direct mmap isn't
990 * possible (as opposed to tried but failed) so we'll try to
991 * make a private copy of the data and map that instead */
992 }
993
994
995 /* allocate some memory to hold the mapping
996 * - note that this may not return a page-aligned address if the object
997 * we're allocating is smaller than a page
998 */
999 order = get_order(len);
1000 total = 1 << order;
1001 point = len >> PAGE_SHIFT;
1002
1003 /* we don't want to allocate a power-of-2 sized page set */
1004 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages)
1005 total = point;
1006
1007 base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
1008 if (!base)
1009 goto enomem;
1010
1011 atomic_long_add(total, &mmap_pages_allocated);
1012
1013 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1014 region->vm_start = (unsigned long) base;
1015 region->vm_end = region->vm_start + len;
1016 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1017
1018 vma->vm_start = region->vm_start;
1019 vma->vm_end = region->vm_start + len;
1020
1021 if (vma->vm_file) {
1022 /* read the contents of a file into the copy */
1023 loff_t fpos;
1024
1025 fpos = vma->vm_pgoff;
1026 fpos <<= PAGE_SHIFT;
1027
1028 ret = kernel_read(vma->vm_file, base, len, &fpos);
1029 if (ret < 0)
1030 goto error_free;
1031
1032 /* clear the last little bit */
1033 if (ret < len)
1034 memset(base + ret, 0, len - ret);
1035
1036 } else {
1037 vma_set_anonymous(vma);
1038 }
1039
1040 return 0;
1041
1042error_free:
1043 free_page_series(region->vm_start, region->vm_top);
1044 region->vm_start = vma->vm_start = 0;
1045 region->vm_end = vma->vm_end = 0;
1046 region->vm_top = 0;
1047 return ret;
1048
1049enomem:
1050 pr_err("Allocation of length %lu from process %d (%s) failed\n",
1051 len, current->pid, current->comm);
1052 show_free_areas(0, NULL);
1053 return -ENOMEM;
1054}
1055
1056/*
1057 * handle mapping creation for uClinux
1058 */
1059unsigned long do_mmap(struct file *file,
1060 unsigned long addr,
1061 unsigned long len,
1062 unsigned long prot,
1063 unsigned long flags,
1064 unsigned long pgoff,
1065 unsigned long *populate,
1066 struct list_head *uf)
1067{
1068 struct vm_area_struct *vma;
1069 struct vm_region *region;
1070 struct rb_node *rb;
1071 vm_flags_t vm_flags;
1072 unsigned long capabilities, result;
1073 int ret;
1074
1075 *populate = 0;
1076
1077 /* decide whether we should attempt the mapping, and if so what sort of
1078 * mapping */
1079 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1080 &capabilities);
1081 if (ret < 0)
1082 return ret;
1083
1084 /* we ignore the address hint */
1085 addr = 0;
1086 len = PAGE_ALIGN(len);
1087
1088 /* we've determined that we can make the mapping, now translate what we
1089 * now know into VMA flags */
1090 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1091
1092 /* we're going to need to record the mapping */
1093 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1094 if (!region)
1095 goto error_getting_region;
1096
1097 vma = vm_area_alloc(current->mm);
1098 if (!vma)
1099 goto error_getting_vma;
1100
1101 region->vm_usage = 1;
1102 region->vm_flags = vm_flags;
1103 region->vm_pgoff = pgoff;
1104
1105 vma->vm_flags = vm_flags;
1106 vma->vm_pgoff = pgoff;
1107
1108 if (file) {
1109 region->vm_file = get_file(file);
1110 vma->vm_file = get_file(file);
1111 }
1112
1113 down_write(&nommu_region_sem);
1114
1115 /* if we want to share, we need to check for regions created by other
1116 * mmap() calls that overlap with our proposed mapping
1117 * - we can only share with a superset match on most regular files
1118 * - shared mappings on character devices and memory backed files are
1119 * permitted to overlap inexactly as far as we are concerned for in
1120 * these cases, sharing is handled in the driver or filesystem rather
1121 * than here
1122 */
1123 if (vm_flags & VM_MAYSHARE) {
1124 struct vm_region *pregion;
1125 unsigned long pglen, rpglen, pgend, rpgend, start;
1126
1127 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1128 pgend = pgoff + pglen;
1129
1130 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1131 pregion = rb_entry(rb, struct vm_region, vm_rb);
1132
1133 if (!(pregion->vm_flags & VM_MAYSHARE))
1134 continue;
1135
1136 /* search for overlapping mappings on the same file */
1137 if (file_inode(pregion->vm_file) !=
1138 file_inode(file))
1139 continue;
1140
1141 if (pregion->vm_pgoff >= pgend)
1142 continue;
1143
1144 rpglen = pregion->vm_end - pregion->vm_start;
1145 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1146 rpgend = pregion->vm_pgoff + rpglen;
1147 if (pgoff >= rpgend)
1148 continue;
1149
1150 /* handle inexactly overlapping matches between
1151 * mappings */
1152 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1153 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1154 /* new mapping is not a subset of the region */
1155 if (!(capabilities & NOMMU_MAP_DIRECT))
1156 goto sharing_violation;
1157 continue;
1158 }
1159
1160 /* we've found a region we can share */
1161 pregion->vm_usage++;
1162 vma->vm_region = pregion;
1163 start = pregion->vm_start;
1164 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1165 vma->vm_start = start;
1166 vma->vm_end = start + len;
1167
1168 if (pregion->vm_flags & VM_MAPPED_COPY)
1169 vma->vm_flags |= VM_MAPPED_COPY;
1170 else {
1171 ret = do_mmap_shared_file(vma);
1172 if (ret < 0) {
1173 vma->vm_region = NULL;
1174 vma->vm_start = 0;
1175 vma->vm_end = 0;
1176 pregion->vm_usage--;
1177 pregion = NULL;
1178 goto error_just_free;
1179 }
1180 }
1181 fput(region->vm_file);
1182 kmem_cache_free(vm_region_jar, region);
1183 region = pregion;
1184 result = start;
1185 goto share;
1186 }
1187
1188 /* obtain the address at which to make a shared mapping
1189 * - this is the hook for quasi-memory character devices to
1190 * tell us the location of a shared mapping
1191 */
1192 if (capabilities & NOMMU_MAP_DIRECT) {
1193 addr = file->f_op->get_unmapped_area(file, addr, len,
1194 pgoff, flags);
1195 if (IS_ERR_VALUE(addr)) {
1196 ret = addr;
1197 if (ret != -ENOSYS)
1198 goto error_just_free;
1199
1200 /* the driver refused to tell us where to site
1201 * the mapping so we'll have to attempt to copy
1202 * it */
1203 ret = -ENODEV;
1204 if (!(capabilities & NOMMU_MAP_COPY))
1205 goto error_just_free;
1206
1207 capabilities &= ~NOMMU_MAP_DIRECT;
1208 } else {
1209 vma->vm_start = region->vm_start = addr;
1210 vma->vm_end = region->vm_end = addr + len;
1211 }
1212 }
1213 }
1214
1215 vma->vm_region = region;
1216
1217 /* set up the mapping
1218 * - the region is filled in if NOMMU_MAP_DIRECT is still set
1219 */
1220 if (file && vma->vm_flags & VM_SHARED)
1221 ret = do_mmap_shared_file(vma);
1222 else
1223 ret = do_mmap_private(vma, region, len, capabilities);
1224 if (ret < 0)
1225 goto error_just_free;
1226 add_nommu_region(region);
1227
1228 /* clear anonymous mappings that don't ask for uninitialized data */
1229 if (!vma->vm_file &&
1230 (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
1231 !(flags & MAP_UNINITIALIZED)))
1232 memset((void *)region->vm_start, 0,
1233 region->vm_end - region->vm_start);
1234
1235 /* okay... we have a mapping; now we have to register it */
1236 result = vma->vm_start;
1237
1238 current->mm->total_vm += len >> PAGE_SHIFT;
1239
1240share:
1241 add_vma_to_mm(current->mm, vma);
1242
1243 /* we flush the region from the icache only when the first executable
1244 * mapping of it is made */
1245 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1246 flush_icache_user_range(region->vm_start, region->vm_end);
1247 region->vm_icache_flushed = true;
1248 }
1249
1250 up_write(&nommu_region_sem);
1251
1252 return result;
1253
1254error_just_free:
1255 up_write(&nommu_region_sem);
1256error:
1257 if (region->vm_file)
1258 fput(region->vm_file);
1259 kmem_cache_free(vm_region_jar, region);
1260 if (vma->vm_file)
1261 fput(vma->vm_file);
1262 vm_area_free(vma);
1263 return ret;
1264
1265sharing_violation:
1266 up_write(&nommu_region_sem);
1267 pr_warn("Attempt to share mismatched mappings\n");
1268 ret = -EINVAL;
1269 goto error;
1270
1271error_getting_vma:
1272 kmem_cache_free(vm_region_jar, region);
1273 pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
1274 len, current->pid);
1275 show_free_areas(0, NULL);
1276 return -ENOMEM;
1277
1278error_getting_region:
1279 pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
1280 len, current->pid);
1281 show_free_areas(0, NULL);
1282 return -ENOMEM;
1283}
1284
1285unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
1286 unsigned long prot, unsigned long flags,
1287 unsigned long fd, unsigned long pgoff)
1288{
1289 struct file *file = NULL;
1290 unsigned long retval = -EBADF;
1291
1292 audit_mmap_fd(fd, flags);
1293 if (!(flags & MAP_ANONYMOUS)) {
1294 file = fget(fd);
1295 if (!file)
1296 goto out;
1297 }
1298
1299 flags &= ~MAP_DENYWRITE;
1300
1301 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1302
1303 if (file)
1304 fput(file);
1305out:
1306 return retval;
1307}
1308
1309SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1310 unsigned long, prot, unsigned long, flags,
1311 unsigned long, fd, unsigned long, pgoff)
1312{
1313 return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
1314}
1315
1316#ifdef __ARCH_WANT_SYS_OLD_MMAP
1317struct mmap_arg_struct {
1318 unsigned long addr;
1319 unsigned long len;
1320 unsigned long prot;
1321 unsigned long flags;
1322 unsigned long fd;
1323 unsigned long offset;
1324};
1325
1326SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1327{
1328 struct mmap_arg_struct a;
1329
1330 if (copy_from_user(&a, arg, sizeof(a)))
1331 return -EFAULT;
1332 if (offset_in_page(a.offset))
1333 return -EINVAL;
1334
1335 return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1336 a.offset >> PAGE_SHIFT);
1337}
1338#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1339
1340/*
1341 * split a vma into two pieces at address 'addr', a new vma is allocated either
1342 * for the first part or the tail.
1343 */
1344int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1345 unsigned long addr, int new_below)
1346{
1347 struct vm_area_struct *new;
1348 struct vm_region *region;
1349 unsigned long npages;
1350
1351 /* we're only permitted to split anonymous regions (these should have
1352 * only a single usage on the region) */
1353 if (vma->vm_file)
1354 return -ENOMEM;
1355
1356 if (mm->map_count >= sysctl_max_map_count)
1357 return -ENOMEM;
1358
1359 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1360 if (!region)
1361 return -ENOMEM;
1362
1363 new = vm_area_dup(vma);
1364 if (!new) {
1365 kmem_cache_free(vm_region_jar, region);
1366 return -ENOMEM;
1367 }
1368
1369 /* most fields are the same, copy all, and then fixup */
1370 *region = *vma->vm_region;
1371 new->vm_region = region;
1372
1373 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1374
1375 if (new_below) {
1376 region->vm_top = region->vm_end = new->vm_end = addr;
1377 } else {
1378 region->vm_start = new->vm_start = addr;
1379 region->vm_pgoff = new->vm_pgoff += npages;
1380 }
1381
1382 if (new->vm_ops && new->vm_ops->open)
1383 new->vm_ops->open(new);
1384
1385 delete_vma_from_mm(vma);
1386 down_write(&nommu_region_sem);
1387 delete_nommu_region(vma->vm_region);
1388 if (new_below) {
1389 vma->vm_region->vm_start = vma->vm_start = addr;
1390 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1391 } else {
1392 vma->vm_region->vm_end = vma->vm_end = addr;
1393 vma->vm_region->vm_top = addr;
1394 }
1395 add_nommu_region(vma->vm_region);
1396 add_nommu_region(new->vm_region);
1397 up_write(&nommu_region_sem);
1398 add_vma_to_mm(mm, vma);
1399 add_vma_to_mm(mm, new);
1400 return 0;
1401}
1402
1403/*
1404 * shrink a VMA by removing the specified chunk from either the beginning or
1405 * the end
1406 */
1407static int shrink_vma(struct mm_struct *mm,
1408 struct vm_area_struct *vma,
1409 unsigned long from, unsigned long to)
1410{
1411 struct vm_region *region;
1412
1413 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1414 * and list */
1415 delete_vma_from_mm(vma);
1416 if (from > vma->vm_start)
1417 vma->vm_end = from;
1418 else
1419 vma->vm_start = to;
1420 add_vma_to_mm(mm, vma);
1421
1422 /* cut the backing region down to size */
1423 region = vma->vm_region;
1424 BUG_ON(region->vm_usage != 1);
1425
1426 down_write(&nommu_region_sem);
1427 delete_nommu_region(region);
1428 if (from > region->vm_start) {
1429 to = region->vm_top;
1430 region->vm_top = region->vm_end = from;
1431 } else {
1432 region->vm_start = to;
1433 }
1434 add_nommu_region(region);
1435 up_write(&nommu_region_sem);
1436
1437 free_page_series(from, to);
1438 return 0;
1439}
1440
1441/*
1442 * release a mapping
1443 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1444 * VMA, though it need not cover the whole VMA
1445 */
1446int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
1447{
1448 struct vm_area_struct *vma;
1449 unsigned long end;
1450 int ret;
1451
1452 len = PAGE_ALIGN(len);
1453 if (len == 0)
1454 return -EINVAL;
1455
1456 end = start + len;
1457
1458 /* find the first potentially overlapping VMA */
1459 vma = find_vma(mm, start);
1460 if (!vma) {
1461 static int limit;
1462 if (limit < 5) {
1463 pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
1464 current->pid, current->comm,
1465 start, start + len - 1);
1466 limit++;
1467 }
1468 return -EINVAL;
1469 }
1470
1471 /* we're allowed to split an anonymous VMA but not a file-backed one */
1472 if (vma->vm_file) {
1473 do {
1474 if (start > vma->vm_start)
1475 return -EINVAL;
1476 if (end == vma->vm_end)
1477 goto erase_whole_vma;
1478 vma = vma->vm_next;
1479 } while (vma);
1480 return -EINVAL;
1481 } else {
1482 /* the chunk must be a subset of the VMA found */
1483 if (start == vma->vm_start && end == vma->vm_end)
1484 goto erase_whole_vma;
1485 if (start < vma->vm_start || end > vma->vm_end)
1486 return -EINVAL;
1487 if (offset_in_page(start))
1488 return -EINVAL;
1489 if (end != vma->vm_end && offset_in_page(end))
1490 return -EINVAL;
1491 if (start != vma->vm_start && end != vma->vm_end) {
1492 ret = split_vma(mm, vma, start, 1);
1493 if (ret < 0)
1494 return ret;
1495 }
1496 return shrink_vma(mm, vma, start, end);
1497 }
1498
1499erase_whole_vma:
1500 delete_vma_from_mm(vma);
1501 delete_vma(mm, vma);
1502 return 0;
1503}
1504
1505int vm_munmap(unsigned long addr, size_t len)
1506{
1507 struct mm_struct *mm = current->mm;
1508 int ret;
1509
1510 mmap_write_lock(mm);
1511 ret = do_munmap(mm, addr, len, NULL);
1512 mmap_write_unlock(mm);
1513 return ret;
1514}
1515EXPORT_SYMBOL(vm_munmap);
1516
1517SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1518{
1519 return vm_munmap(addr, len);
1520}
1521
1522/*
1523 * release all the mappings made in a process's VM space
1524 */
1525void exit_mmap(struct mm_struct *mm)
1526{
1527 struct vm_area_struct *vma;
1528
1529 if (!mm)
1530 return;
1531
1532 mm->total_vm = 0;
1533
1534 while ((vma = mm->mmap)) {
1535 mm->mmap = vma->vm_next;
1536 delete_vma_from_mm(vma);
1537 delete_vma(mm, vma);
1538 cond_resched();
1539 }
1540}
1541
1542int vm_brk(unsigned long addr, unsigned long len)
1543{
1544 return -ENOMEM;
1545}
1546
1547/*
1548 * expand (or shrink) an existing mapping, potentially moving it at the same
1549 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1550 *
1551 * under NOMMU conditions, we only permit changing a mapping's size, and only
1552 * as long as it stays within the region allocated by do_mmap_private() and the
1553 * block is not shareable
1554 *
1555 * MREMAP_FIXED is not supported under NOMMU conditions
1556 */
1557static unsigned long do_mremap(unsigned long addr,
1558 unsigned long old_len, unsigned long new_len,
1559 unsigned long flags, unsigned long new_addr)
1560{
1561 struct vm_area_struct *vma;
1562
1563 /* insanity checks first */
1564 old_len = PAGE_ALIGN(old_len);
1565 new_len = PAGE_ALIGN(new_len);
1566 if (old_len == 0 || new_len == 0)
1567 return (unsigned long) -EINVAL;
1568
1569 if (offset_in_page(addr))
1570 return -EINVAL;
1571
1572 if (flags & MREMAP_FIXED && new_addr != addr)
1573 return (unsigned long) -EINVAL;
1574
1575 vma = find_vma_exact(current->mm, addr, old_len);
1576 if (!vma)
1577 return (unsigned long) -EINVAL;
1578
1579 if (vma->vm_end != vma->vm_start + old_len)
1580 return (unsigned long) -EFAULT;
1581
1582 if (vma->vm_flags & VM_MAYSHARE)
1583 return (unsigned long) -EPERM;
1584
1585 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1586 return (unsigned long) -ENOMEM;
1587
1588 /* all checks complete - do it */
1589 vma->vm_end = vma->vm_start + new_len;
1590 return vma->vm_start;
1591}
1592
1593SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1594 unsigned long, new_len, unsigned long, flags,
1595 unsigned long, new_addr)
1596{
1597 unsigned long ret;
1598
1599 mmap_write_lock(current->mm);
1600 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1601 mmap_write_unlock(current->mm);
1602 return ret;
1603}
1604
1605struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1606 unsigned int foll_flags)
1607{
1608 return NULL;
1609}
1610
1611int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1612 unsigned long pfn, unsigned long size, pgprot_t prot)
1613{
1614 if (addr != (pfn << PAGE_SHIFT))
1615 return -EINVAL;
1616
1617 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1618 return 0;
1619}
1620EXPORT_SYMBOL(remap_pfn_range);
1621
1622int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1623{
1624 unsigned long pfn = start >> PAGE_SHIFT;
1625 unsigned long vm_len = vma->vm_end - vma->vm_start;
1626
1627 pfn += vma->vm_pgoff;
1628 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1629}
1630EXPORT_SYMBOL(vm_iomap_memory);
1631
1632int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1633 unsigned long pgoff)
1634{
1635 unsigned int size = vma->vm_end - vma->vm_start;
1636
1637 if (!(vma->vm_flags & VM_USERMAP))
1638 return -EINVAL;
1639
1640 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1641 vma->vm_end = vma->vm_start + size;
1642
1643 return 0;
1644}
1645EXPORT_SYMBOL(remap_vmalloc_range);
1646
1647unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1648 unsigned long len, unsigned long pgoff, unsigned long flags)
1649{
1650 return -ENOMEM;
1651}
1652
1653vm_fault_t filemap_fault(struct vm_fault *vmf)
1654{
1655 BUG();
1656 return 0;
1657}
1658EXPORT_SYMBOL(filemap_fault);
1659
1660vm_fault_t filemap_map_pages(struct vm_fault *vmf,
1661 pgoff_t start_pgoff, pgoff_t end_pgoff)
1662{
1663 BUG();
1664 return 0;
1665}
1666EXPORT_SYMBOL(filemap_map_pages);
1667
1668int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
1669 int len, unsigned int gup_flags)
1670{
1671 struct vm_area_struct *vma;
1672 int write = gup_flags & FOLL_WRITE;
1673
1674 if (mmap_read_lock_killable(mm))
1675 return 0;
1676
1677 /* the access must start within one of the target process's mappings */
1678 vma = find_vma(mm, addr);
1679 if (vma) {
1680 /* don't overrun this mapping */
1681 if (addr + len >= vma->vm_end)
1682 len = vma->vm_end - addr;
1683
1684 /* only read or write mappings where it is permitted */
1685 if (write && vma->vm_flags & VM_MAYWRITE)
1686 copy_to_user_page(vma, NULL, addr,
1687 (void *) addr, buf, len);
1688 else if (!write && vma->vm_flags & VM_MAYREAD)
1689 copy_from_user_page(vma, NULL, addr,
1690 buf, (void *) addr, len);
1691 else
1692 len = 0;
1693 } else {
1694 len = 0;
1695 }
1696
1697 mmap_read_unlock(mm);
1698
1699 return len;
1700}
1701
1702/**
1703 * access_remote_vm - access another process' address space
1704 * @mm: the mm_struct of the target address space
1705 * @addr: start address to access
1706 * @buf: source or destination buffer
1707 * @len: number of bytes to transfer
1708 * @gup_flags: flags modifying lookup behaviour
1709 *
1710 * The caller must hold a reference on @mm.
1711 */
1712int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1713 void *buf, int len, unsigned int gup_flags)
1714{
1715 return __access_remote_vm(mm, addr, buf, len, gup_flags);
1716}
1717
1718/*
1719 * Access another process' address space.
1720 * - source/target buffer must be kernel space
1721 */
1722int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
1723 unsigned int gup_flags)
1724{
1725 struct mm_struct *mm;
1726
1727 if (addr + len < addr)
1728 return 0;
1729
1730 mm = get_task_mm(tsk);
1731 if (!mm)
1732 return 0;
1733
1734 len = __access_remote_vm(mm, addr, buf, len, gup_flags);
1735
1736 mmput(mm);
1737 return len;
1738}
1739EXPORT_SYMBOL_GPL(access_process_vm);
1740
1741/**
1742 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
1743 * @inode: The inode to check
1744 * @size: The current filesize of the inode
1745 * @newsize: The proposed filesize of the inode
1746 *
1747 * Check the shared mappings on an inode on behalf of a shrinking truncate to
1748 * make sure that any outstanding VMAs aren't broken and then shrink the
1749 * vm_regions that extend beyond so that do_mmap() doesn't
1750 * automatically grant mappings that are too large.
1751 */
1752int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
1753 size_t newsize)
1754{
1755 struct vm_area_struct *vma;
1756 struct vm_region *region;
1757 pgoff_t low, high;
1758 size_t r_size, r_top;
1759
1760 low = newsize >> PAGE_SHIFT;
1761 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1762
1763 down_write(&nommu_region_sem);
1764 i_mmap_lock_read(inode->i_mapping);
1765
1766 /* search for VMAs that fall within the dead zone */
1767 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
1768 /* found one - only interested if it's shared out of the page
1769 * cache */
1770 if (vma->vm_flags & VM_SHARED) {
1771 i_mmap_unlock_read(inode->i_mapping);
1772 up_write(&nommu_region_sem);
1773 return -ETXTBSY; /* not quite true, but near enough */
1774 }
1775 }
1776
1777 /* reduce any regions that overlap the dead zone - if in existence,
1778 * these will be pointed to by VMAs that don't overlap the dead zone
1779 *
1780 * we don't check for any regions that start beyond the EOF as there
1781 * shouldn't be any
1782 */
1783 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
1784 if (!(vma->vm_flags & VM_SHARED))
1785 continue;
1786
1787 region = vma->vm_region;
1788 r_size = region->vm_top - region->vm_start;
1789 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
1790
1791 if (r_top > newsize) {
1792 region->vm_top -= r_top - newsize;
1793 if (region->vm_end > region->vm_top)
1794 region->vm_end = region->vm_top;
1795 }
1796 }
1797
1798 i_mmap_unlock_read(inode->i_mapping);
1799 up_write(&nommu_region_sem);
1800 return 0;
1801}
1802
1803/*
1804 * Initialise sysctl_user_reserve_kbytes.
1805 *
1806 * This is intended to prevent a user from starting a single memory hogging
1807 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
1808 * mode.
1809 *
1810 * The default value is min(3% of free memory, 128MB)
1811 * 128MB is enough to recover with sshd/login, bash, and top/kill.
1812 */
1813static int __meminit init_user_reserve(void)
1814{
1815 unsigned long free_kbytes;
1816
1817 free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
1818
1819 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
1820 return 0;
1821}
1822subsys_initcall(init_user_reserve);
1823
1824/*
1825 * Initialise sysctl_admin_reserve_kbytes.
1826 *
1827 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
1828 * to log in and kill a memory hogging process.
1829 *
1830 * Systems with more than 256MB will reserve 8MB, enough to recover
1831 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
1832 * only reserve 3% of free pages by default.
1833 */
1834static int __meminit init_admin_reserve(void)
1835{
1836 unsigned long free_kbytes;
1837
1838 free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
1839
1840 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
1841 return 0;
1842}
1843subsys_initcall(init_admin_reserve);
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/vmacache.h>
19#include <linux/mman.h>
20#include <linux/swap.h>
21#include <linux/file.h>
22#include <linux/highmem.h>
23#include <linux/pagemap.h>
24#include <linux/slab.h>
25#include <linux/vmalloc.h>
26#include <linux/blkdev.h>
27#include <linux/backing-dev.h>
28#include <linux/compiler.h>
29#include <linux/mount.h>
30#include <linux/personality.h>
31#include <linux/security.h>
32#include <linux/syscalls.h>
33#include <linux/audit.h>
34#include <linux/sched/sysctl.h>
35
36#include <asm/uaccess.h>
37#include <asm/tlb.h>
38#include <asm/tlbflush.h>
39#include <asm/mmu_context.h>
40#include "internal.h"
41
42#if 0
43#define kenter(FMT, ...) \
44 printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
45#define kleave(FMT, ...) \
46 printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
47#define kdebug(FMT, ...) \
48 printk(KERN_DEBUG "xxx" FMT"yyy\n", ##__VA_ARGS__)
49#else
50#define kenter(FMT, ...) \
51 no_printk(KERN_DEBUG "==> %s("FMT")\n", __func__, ##__VA_ARGS__)
52#define kleave(FMT, ...) \
53 no_printk(KERN_DEBUG "<== %s()"FMT"\n", __func__, ##__VA_ARGS__)
54#define kdebug(FMT, ...) \
55 no_printk(KERN_DEBUG FMT"\n", ##__VA_ARGS__)
56#endif
57
58void *high_memory;
59struct page *mem_map;
60unsigned long max_mapnr;
61unsigned long highest_memmap_pfn;
62struct percpu_counter vm_committed_as;
63int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
64int sysctl_overcommit_ratio = 50; /* default is 50% */
65unsigned long sysctl_overcommit_kbytes __read_mostly;
66int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
67int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
68unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */
69unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */
70int heap_stack_gap = 0;
71
72atomic_long_t mmap_pages_allocated;
73
74/*
75 * The global memory commitment made in the system can be a metric
76 * that can be used to drive ballooning decisions when Linux is hosted
77 * as a guest. On Hyper-V, the host implements a policy engine for dynamically
78 * balancing memory across competing virtual machines that are hosted.
79 * Several metrics drive this policy engine including the guest reported
80 * memory commitment.
81 */
82unsigned long vm_memory_committed(void)
83{
84 return percpu_counter_read_positive(&vm_committed_as);
85}
86
87EXPORT_SYMBOL_GPL(vm_memory_committed);
88
89EXPORT_SYMBOL(mem_map);
90
91/* list of mapped, potentially shareable regions */
92static struct kmem_cache *vm_region_jar;
93struct rb_root nommu_region_tree = RB_ROOT;
94DECLARE_RWSEM(nommu_region_sem);
95
96const struct vm_operations_struct generic_file_vm_ops = {
97};
98
99/*
100 * Return the total memory allocated for this pointer, not
101 * just what the caller asked for.
102 *
103 * Doesn't have to be accurate, i.e. may have races.
104 */
105unsigned int kobjsize(const void *objp)
106{
107 struct page *page;
108
109 /*
110 * If the object we have should not have ksize performed on it,
111 * return size of 0
112 */
113 if (!objp || !virt_addr_valid(objp))
114 return 0;
115
116 page = virt_to_head_page(objp);
117
118 /*
119 * If the allocator sets PageSlab, we know the pointer came from
120 * kmalloc().
121 */
122 if (PageSlab(page))
123 return ksize(objp);
124
125 /*
126 * If it's not a compound page, see if we have a matching VMA
127 * region. This test is intentionally done in reverse order,
128 * so if there's no VMA, we still fall through and hand back
129 * PAGE_SIZE for 0-order pages.
130 */
131 if (!PageCompound(page)) {
132 struct vm_area_struct *vma;
133
134 vma = find_vma(current->mm, (unsigned long)objp);
135 if (vma)
136 return vma->vm_end - vma->vm_start;
137 }
138
139 /*
140 * The ksize() function is only guaranteed to work for pointers
141 * returned by kmalloc(). So handle arbitrary pointers here.
142 */
143 return PAGE_SIZE << compound_order(page);
144}
145
146long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
147 unsigned long start, unsigned long nr_pages,
148 unsigned int foll_flags, struct page **pages,
149 struct vm_area_struct **vmas, int *nonblocking)
150{
151 struct vm_area_struct *vma;
152 unsigned long vm_flags;
153 int i;
154
155 /* calculate required read or write permissions.
156 * If FOLL_FORCE is set, we only require the "MAY" flags.
157 */
158 vm_flags = (foll_flags & FOLL_WRITE) ?
159 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
160 vm_flags &= (foll_flags & FOLL_FORCE) ?
161 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
162
163 for (i = 0; i < nr_pages; i++) {
164 vma = find_vma(mm, start);
165 if (!vma)
166 goto finish_or_fault;
167
168 /* protect what we can, including chardevs */
169 if ((vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
170 !(vm_flags & vma->vm_flags))
171 goto finish_or_fault;
172
173 if (pages) {
174 pages[i] = virt_to_page(start);
175 if (pages[i])
176 page_cache_get(pages[i]);
177 }
178 if (vmas)
179 vmas[i] = vma;
180 start = (start + PAGE_SIZE) & PAGE_MASK;
181 }
182
183 return i;
184
185finish_or_fault:
186 return i ? : -EFAULT;
187}
188
189/*
190 * get a list of pages in an address range belonging to the specified process
191 * and indicate the VMA that covers each page
192 * - this is potentially dodgy as we may end incrementing the page count of a
193 * slab page or a secondary page from a compound page
194 * - don't permit access to VMAs that don't support it, such as I/O mappings
195 */
196long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
197 unsigned long start, unsigned long nr_pages,
198 int write, int force, struct page **pages,
199 struct vm_area_struct **vmas)
200{
201 int flags = 0;
202
203 if (write)
204 flags |= FOLL_WRITE;
205 if (force)
206 flags |= FOLL_FORCE;
207
208 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
209 NULL);
210}
211EXPORT_SYMBOL(get_user_pages);
212
213/**
214 * follow_pfn - look up PFN at a user virtual address
215 * @vma: memory mapping
216 * @address: user virtual address
217 * @pfn: location to store found PFN
218 *
219 * Only IO mappings and raw PFN mappings are allowed.
220 *
221 * Returns zero and the pfn at @pfn on success, -ve otherwise.
222 */
223int follow_pfn(struct vm_area_struct *vma, unsigned long address,
224 unsigned long *pfn)
225{
226 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
227 return -EINVAL;
228
229 *pfn = address >> PAGE_SHIFT;
230 return 0;
231}
232EXPORT_SYMBOL(follow_pfn);
233
234LIST_HEAD(vmap_area_list);
235
236void vfree(const void *addr)
237{
238 kfree(addr);
239}
240EXPORT_SYMBOL(vfree);
241
242void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
243{
244 /*
245 * You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
246 * returns only a logical address.
247 */
248 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
249}
250EXPORT_SYMBOL(__vmalloc);
251
252void *vmalloc_user(unsigned long size)
253{
254 void *ret;
255
256 ret = __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
257 PAGE_KERNEL);
258 if (ret) {
259 struct vm_area_struct *vma;
260
261 down_write(¤t->mm->mmap_sem);
262 vma = find_vma(current->mm, (unsigned long)ret);
263 if (vma)
264 vma->vm_flags |= VM_USERMAP;
265 up_write(¤t->mm->mmap_sem);
266 }
267
268 return ret;
269}
270EXPORT_SYMBOL(vmalloc_user);
271
272struct page *vmalloc_to_page(const void *addr)
273{
274 return virt_to_page(addr);
275}
276EXPORT_SYMBOL(vmalloc_to_page);
277
278unsigned long vmalloc_to_pfn(const void *addr)
279{
280 return page_to_pfn(virt_to_page(addr));
281}
282EXPORT_SYMBOL(vmalloc_to_pfn);
283
284long vread(char *buf, char *addr, unsigned long count)
285{
286 /* Don't allow overflow */
287 if ((unsigned long) buf + count < count)
288 count = -(unsigned long) buf;
289
290 memcpy(buf, addr, count);
291 return count;
292}
293
294long vwrite(char *buf, char *addr, unsigned long count)
295{
296 /* Don't allow overflow */
297 if ((unsigned long) addr + count < count)
298 count = -(unsigned long) addr;
299
300 memcpy(addr, buf, count);
301 return count;
302}
303
304/*
305 * vmalloc - allocate virtually continguos memory
306 *
307 * @size: allocation size
308 *
309 * Allocate enough pages to cover @size from the page level
310 * allocator and map them into continguos kernel virtual space.
311 *
312 * For tight control over page level allocator and protection flags
313 * use __vmalloc() instead.
314 */
315void *vmalloc(unsigned long size)
316{
317 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
318}
319EXPORT_SYMBOL(vmalloc);
320
321/*
322 * vzalloc - allocate virtually continguos memory with zero fill
323 *
324 * @size: allocation size
325 *
326 * Allocate enough pages to cover @size from the page level
327 * allocator and map them into continguos kernel virtual space.
328 * The memory allocated is set to zero.
329 *
330 * For tight control over page level allocator and protection flags
331 * use __vmalloc() instead.
332 */
333void *vzalloc(unsigned long size)
334{
335 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
336 PAGE_KERNEL);
337}
338EXPORT_SYMBOL(vzalloc);
339
340/**
341 * vmalloc_node - allocate memory on a specific node
342 * @size: allocation size
343 * @node: numa node
344 *
345 * Allocate enough pages to cover @size from the page level
346 * allocator and map them into contiguous kernel virtual space.
347 *
348 * For tight control over page level allocator and protection flags
349 * use __vmalloc() instead.
350 */
351void *vmalloc_node(unsigned long size, int node)
352{
353 return vmalloc(size);
354}
355EXPORT_SYMBOL(vmalloc_node);
356
357/**
358 * vzalloc_node - allocate memory on a specific node with zero fill
359 * @size: allocation size
360 * @node: numa node
361 *
362 * Allocate enough pages to cover @size from the page level
363 * allocator and map them into contiguous kernel virtual space.
364 * The memory allocated is set to zero.
365 *
366 * For tight control over page level allocator and protection flags
367 * use __vmalloc() instead.
368 */
369void *vzalloc_node(unsigned long size, int node)
370{
371 return vzalloc(size);
372}
373EXPORT_SYMBOL(vzalloc_node);
374
375#ifndef PAGE_KERNEL_EXEC
376# define PAGE_KERNEL_EXEC PAGE_KERNEL
377#endif
378
379/**
380 * vmalloc_exec - allocate virtually contiguous, executable memory
381 * @size: allocation size
382 *
383 * Kernel-internal function to allocate enough pages to cover @size
384 * the page level allocator and map them into contiguous and
385 * executable kernel virtual space.
386 *
387 * For tight control over page level allocator and protection flags
388 * use __vmalloc() instead.
389 */
390
391void *vmalloc_exec(unsigned long size)
392{
393 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
394}
395
396/**
397 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
398 * @size: allocation size
399 *
400 * Allocate enough 32bit PA addressable pages to cover @size from the
401 * page level allocator and map them into continguos kernel virtual space.
402 */
403void *vmalloc_32(unsigned long size)
404{
405 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
406}
407EXPORT_SYMBOL(vmalloc_32);
408
409/**
410 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
411 * @size: allocation size
412 *
413 * The resulting memory area is 32bit addressable and zeroed so it can be
414 * mapped to userspace without leaking data.
415 *
416 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
417 * remap_vmalloc_range() are permissible.
418 */
419void *vmalloc_32_user(unsigned long size)
420{
421 /*
422 * We'll have to sort out the ZONE_DMA bits for 64-bit,
423 * but for now this can simply use vmalloc_user() directly.
424 */
425 return vmalloc_user(size);
426}
427EXPORT_SYMBOL(vmalloc_32_user);
428
429void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
430{
431 BUG();
432 return NULL;
433}
434EXPORT_SYMBOL(vmap);
435
436void vunmap(const void *addr)
437{
438 BUG();
439}
440EXPORT_SYMBOL(vunmap);
441
442void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
443{
444 BUG();
445 return NULL;
446}
447EXPORT_SYMBOL(vm_map_ram);
448
449void vm_unmap_ram(const void *mem, unsigned int count)
450{
451 BUG();
452}
453EXPORT_SYMBOL(vm_unmap_ram);
454
455void vm_unmap_aliases(void)
456{
457}
458EXPORT_SYMBOL_GPL(vm_unmap_aliases);
459
460/*
461 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
462 * have one.
463 */
464void __weak vmalloc_sync_all(void)
465{
466}
467
468/**
469 * alloc_vm_area - allocate a range of kernel address space
470 * @size: size of the area
471 *
472 * Returns: NULL on failure, vm_struct on success
473 *
474 * This function reserves a range of kernel address space, and
475 * allocates pagetables to map that range. No actual mappings
476 * are created. If the kernel address space is not shared
477 * between processes, it syncs the pagetable across all
478 * processes.
479 */
480struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
481{
482 BUG();
483 return NULL;
484}
485EXPORT_SYMBOL_GPL(alloc_vm_area);
486
487void free_vm_area(struct vm_struct *area)
488{
489 BUG();
490}
491EXPORT_SYMBOL_GPL(free_vm_area);
492
493int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
494 struct page *page)
495{
496 return -EINVAL;
497}
498EXPORT_SYMBOL(vm_insert_page);
499
500/*
501 * sys_brk() for the most part doesn't need the global kernel
502 * lock, except when an application is doing something nasty
503 * like trying to un-brk an area that has already been mapped
504 * to a regular file. in this case, the unmapping will need
505 * to invoke file system routines that need the global lock.
506 */
507SYSCALL_DEFINE1(brk, unsigned long, brk)
508{
509 struct mm_struct *mm = current->mm;
510
511 if (brk < mm->start_brk || brk > mm->context.end_brk)
512 return mm->brk;
513
514 if (mm->brk == brk)
515 return mm->brk;
516
517 /*
518 * Always allow shrinking brk
519 */
520 if (brk <= mm->brk) {
521 mm->brk = brk;
522 return brk;
523 }
524
525 /*
526 * Ok, looks good - let it rip.
527 */
528 flush_icache_range(mm->brk, brk);
529 return mm->brk = brk;
530}
531
532/*
533 * initialise the VMA and region record slabs
534 */
535void __init mmap_init(void)
536{
537 int ret;
538
539 ret = percpu_counter_init(&vm_committed_as, 0);
540 VM_BUG_ON(ret);
541 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC);
542}
543
544/*
545 * validate the region tree
546 * - the caller must hold the region lock
547 */
548#ifdef CONFIG_DEBUG_NOMMU_REGIONS
549static noinline void validate_nommu_regions(void)
550{
551 struct vm_region *region, *last;
552 struct rb_node *p, *lastp;
553
554 lastp = rb_first(&nommu_region_tree);
555 if (!lastp)
556 return;
557
558 last = rb_entry(lastp, struct vm_region, vm_rb);
559 BUG_ON(unlikely(last->vm_end <= last->vm_start));
560 BUG_ON(unlikely(last->vm_top < last->vm_end));
561
562 while ((p = rb_next(lastp))) {
563 region = rb_entry(p, struct vm_region, vm_rb);
564 last = rb_entry(lastp, struct vm_region, vm_rb);
565
566 BUG_ON(unlikely(region->vm_end <= region->vm_start));
567 BUG_ON(unlikely(region->vm_top < region->vm_end));
568 BUG_ON(unlikely(region->vm_start < last->vm_top));
569
570 lastp = p;
571 }
572}
573#else
574static void validate_nommu_regions(void)
575{
576}
577#endif
578
579/*
580 * add a region into the global tree
581 */
582static void add_nommu_region(struct vm_region *region)
583{
584 struct vm_region *pregion;
585 struct rb_node **p, *parent;
586
587 validate_nommu_regions();
588
589 parent = NULL;
590 p = &nommu_region_tree.rb_node;
591 while (*p) {
592 parent = *p;
593 pregion = rb_entry(parent, struct vm_region, vm_rb);
594 if (region->vm_start < pregion->vm_start)
595 p = &(*p)->rb_left;
596 else if (region->vm_start > pregion->vm_start)
597 p = &(*p)->rb_right;
598 else if (pregion == region)
599 return;
600 else
601 BUG();
602 }
603
604 rb_link_node(®ion->vm_rb, parent, p);
605 rb_insert_color(®ion->vm_rb, &nommu_region_tree);
606
607 validate_nommu_regions();
608}
609
610/*
611 * delete a region from the global tree
612 */
613static void delete_nommu_region(struct vm_region *region)
614{
615 BUG_ON(!nommu_region_tree.rb_node);
616
617 validate_nommu_regions();
618 rb_erase(®ion->vm_rb, &nommu_region_tree);
619 validate_nommu_regions();
620}
621
622/*
623 * free a contiguous series of pages
624 */
625static void free_page_series(unsigned long from, unsigned long to)
626{
627 for (; from < to; from += PAGE_SIZE) {
628 struct page *page = virt_to_page(from);
629
630 kdebug("- free %lx", from);
631 atomic_long_dec(&mmap_pages_allocated);
632 if (page_count(page) != 1)
633 kdebug("free page %p: refcount not one: %d",
634 page, page_count(page));
635 put_page(page);
636 }
637}
638
639/*
640 * release a reference to a region
641 * - the caller must hold the region semaphore for writing, which this releases
642 * - the region may not have been added to the tree yet, in which case vm_top
643 * will equal vm_start
644 */
645static void __put_nommu_region(struct vm_region *region)
646 __releases(nommu_region_sem)
647{
648 kenter("%p{%d}", region, region->vm_usage);
649
650 BUG_ON(!nommu_region_tree.rb_node);
651
652 if (--region->vm_usage == 0) {
653 if (region->vm_top > region->vm_start)
654 delete_nommu_region(region);
655 up_write(&nommu_region_sem);
656
657 if (region->vm_file)
658 fput(region->vm_file);
659
660 /* IO memory and memory shared directly out of the pagecache
661 * from ramfs/tmpfs mustn't be released here */
662 if (region->vm_flags & VM_MAPPED_COPY) {
663 kdebug("free series");
664 free_page_series(region->vm_start, region->vm_top);
665 }
666 kmem_cache_free(vm_region_jar, region);
667 } else {
668 up_write(&nommu_region_sem);
669 }
670}
671
672/*
673 * release a reference to a region
674 */
675static void put_nommu_region(struct vm_region *region)
676{
677 down_write(&nommu_region_sem);
678 __put_nommu_region(region);
679}
680
681/*
682 * update protection on a vma
683 */
684static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
685{
686#ifdef CONFIG_MPU
687 struct mm_struct *mm = vma->vm_mm;
688 long start = vma->vm_start & PAGE_MASK;
689 while (start < vma->vm_end) {
690 protect_page(mm, start, flags);
691 start += PAGE_SIZE;
692 }
693 update_protections(mm);
694#endif
695}
696
697/*
698 * add a VMA into a process's mm_struct in the appropriate place in the list
699 * and tree and add to the address space's page tree also if not an anonymous
700 * page
701 * - should be called with mm->mmap_sem held writelocked
702 */
703static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
704{
705 struct vm_area_struct *pvma, *prev;
706 struct address_space *mapping;
707 struct rb_node **p, *parent, *rb_prev;
708
709 kenter(",%p", vma);
710
711 BUG_ON(!vma->vm_region);
712
713 mm->map_count++;
714 vma->vm_mm = mm;
715
716 protect_vma(vma, vma->vm_flags);
717
718 /* add the VMA to the mapping */
719 if (vma->vm_file) {
720 mapping = vma->vm_file->f_mapping;
721
722 mutex_lock(&mapping->i_mmap_mutex);
723 flush_dcache_mmap_lock(mapping);
724 vma_interval_tree_insert(vma, &mapping->i_mmap);
725 flush_dcache_mmap_unlock(mapping);
726 mutex_unlock(&mapping->i_mmap_mutex);
727 }
728
729 /* add the VMA to the tree */
730 parent = rb_prev = NULL;
731 p = &mm->mm_rb.rb_node;
732 while (*p) {
733 parent = *p;
734 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
735
736 /* sort by: start addr, end addr, VMA struct addr in that order
737 * (the latter is necessary as we may get identical VMAs) */
738 if (vma->vm_start < pvma->vm_start)
739 p = &(*p)->rb_left;
740 else if (vma->vm_start > pvma->vm_start) {
741 rb_prev = parent;
742 p = &(*p)->rb_right;
743 } else if (vma->vm_end < pvma->vm_end)
744 p = &(*p)->rb_left;
745 else if (vma->vm_end > pvma->vm_end) {
746 rb_prev = parent;
747 p = &(*p)->rb_right;
748 } else if (vma < pvma)
749 p = &(*p)->rb_left;
750 else if (vma > pvma) {
751 rb_prev = parent;
752 p = &(*p)->rb_right;
753 } else
754 BUG();
755 }
756
757 rb_link_node(&vma->vm_rb, parent, p);
758 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
759
760 /* add VMA to the VMA list also */
761 prev = NULL;
762 if (rb_prev)
763 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
764
765 __vma_link_list(mm, vma, prev, parent);
766}
767
768/*
769 * delete a VMA from its owning mm_struct and address space
770 */
771static void delete_vma_from_mm(struct vm_area_struct *vma)
772{
773 int i;
774 struct address_space *mapping;
775 struct mm_struct *mm = vma->vm_mm;
776 struct task_struct *curr = current;
777
778 kenter("%p", vma);
779
780 protect_vma(vma, 0);
781
782 mm->map_count--;
783 for (i = 0; i < VMACACHE_SIZE; i++) {
784 /* if the vma is cached, invalidate the entire cache */
785 if (curr->vmacache[i] == vma) {
786 vmacache_invalidate(curr->mm);
787 break;
788 }
789 }
790
791 /* remove the VMA from the mapping */
792 if (vma->vm_file) {
793 mapping = vma->vm_file->f_mapping;
794
795 mutex_lock(&mapping->i_mmap_mutex);
796 flush_dcache_mmap_lock(mapping);
797 vma_interval_tree_remove(vma, &mapping->i_mmap);
798 flush_dcache_mmap_unlock(mapping);
799 mutex_unlock(&mapping->i_mmap_mutex);
800 }
801
802 /* remove from the MM's tree and list */
803 rb_erase(&vma->vm_rb, &mm->mm_rb);
804
805 if (vma->vm_prev)
806 vma->vm_prev->vm_next = vma->vm_next;
807 else
808 mm->mmap = vma->vm_next;
809
810 if (vma->vm_next)
811 vma->vm_next->vm_prev = vma->vm_prev;
812}
813
814/*
815 * destroy a VMA record
816 */
817static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
818{
819 kenter("%p", vma);
820 if (vma->vm_ops && vma->vm_ops->close)
821 vma->vm_ops->close(vma);
822 if (vma->vm_file)
823 fput(vma->vm_file);
824 put_nommu_region(vma->vm_region);
825 kmem_cache_free(vm_area_cachep, vma);
826}
827
828/*
829 * look up the first VMA in which addr resides, NULL if none
830 * - should be called with mm->mmap_sem at least held readlocked
831 */
832struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
833{
834 struct vm_area_struct *vma;
835
836 /* check the cache first */
837 vma = vmacache_find(mm, addr);
838 if (likely(vma))
839 return vma;
840
841 /* trawl the list (there may be multiple mappings in which addr
842 * resides) */
843 for (vma = mm->mmap; vma; vma = vma->vm_next) {
844 if (vma->vm_start > addr)
845 return NULL;
846 if (vma->vm_end > addr) {
847 vmacache_update(addr, vma);
848 return vma;
849 }
850 }
851
852 return NULL;
853}
854EXPORT_SYMBOL(find_vma);
855
856/*
857 * find a VMA
858 * - we don't extend stack VMAs under NOMMU conditions
859 */
860struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
861{
862 return find_vma(mm, addr);
863}
864
865/*
866 * expand a stack to a given address
867 * - not supported under NOMMU conditions
868 */
869int expand_stack(struct vm_area_struct *vma, unsigned long address)
870{
871 return -ENOMEM;
872}
873
874/*
875 * look up the first VMA exactly that exactly matches addr
876 * - should be called with mm->mmap_sem at least held readlocked
877 */
878static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
879 unsigned long addr,
880 unsigned long len)
881{
882 struct vm_area_struct *vma;
883 unsigned long end = addr + len;
884
885 /* check the cache first */
886 vma = vmacache_find_exact(mm, addr, end);
887 if (vma)
888 return vma;
889
890 /* trawl the list (there may be multiple mappings in which addr
891 * resides) */
892 for (vma = mm->mmap; vma; vma = vma->vm_next) {
893 if (vma->vm_start < addr)
894 continue;
895 if (vma->vm_start > addr)
896 return NULL;
897 if (vma->vm_end == end) {
898 vmacache_update(addr, vma);
899 return vma;
900 }
901 }
902
903 return NULL;
904}
905
906/*
907 * determine whether a mapping should be permitted and, if so, what sort of
908 * mapping we're capable of supporting
909 */
910static int validate_mmap_request(struct file *file,
911 unsigned long addr,
912 unsigned long len,
913 unsigned long prot,
914 unsigned long flags,
915 unsigned long pgoff,
916 unsigned long *_capabilities)
917{
918 unsigned long capabilities, rlen;
919 int ret;
920
921 /* do the simple checks first */
922 if (flags & MAP_FIXED) {
923 printk(KERN_DEBUG
924 "%d: Can't do fixed-address/overlay mmap of RAM\n",
925 current->pid);
926 return -EINVAL;
927 }
928
929 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
930 (flags & MAP_TYPE) != MAP_SHARED)
931 return -EINVAL;
932
933 if (!len)
934 return -EINVAL;
935
936 /* Careful about overflows.. */
937 rlen = PAGE_ALIGN(len);
938 if (!rlen || rlen > TASK_SIZE)
939 return -ENOMEM;
940
941 /* offset overflow? */
942 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
943 return -EOVERFLOW;
944
945 if (file) {
946 /* validate file mapping requests */
947 struct address_space *mapping;
948
949 /* files must support mmap */
950 if (!file->f_op->mmap)
951 return -ENODEV;
952
953 /* work out if what we've got could possibly be shared
954 * - we support chardevs that provide their own "memory"
955 * - we support files/blockdevs that are memory backed
956 */
957 mapping = file->f_mapping;
958 if (!mapping)
959 mapping = file_inode(file)->i_mapping;
960
961 capabilities = 0;
962 if (mapping && mapping->backing_dev_info)
963 capabilities = mapping->backing_dev_info->capabilities;
964
965 if (!capabilities) {
966 /* no explicit capabilities set, so assume some
967 * defaults */
968 switch (file_inode(file)->i_mode & S_IFMT) {
969 case S_IFREG:
970 case S_IFBLK:
971 capabilities = BDI_CAP_MAP_COPY;
972 break;
973
974 case S_IFCHR:
975 capabilities =
976 BDI_CAP_MAP_DIRECT |
977 BDI_CAP_READ_MAP |
978 BDI_CAP_WRITE_MAP;
979 break;
980
981 default:
982 return -EINVAL;
983 }
984 }
985
986 /* eliminate any capabilities that we can't support on this
987 * device */
988 if (!file->f_op->get_unmapped_area)
989 capabilities &= ~BDI_CAP_MAP_DIRECT;
990 if (!file->f_op->read)
991 capabilities &= ~BDI_CAP_MAP_COPY;
992
993 /* The file shall have been opened with read permission. */
994 if (!(file->f_mode & FMODE_READ))
995 return -EACCES;
996
997 if (flags & MAP_SHARED) {
998 /* do checks for writing, appending and locking */
999 if ((prot & PROT_WRITE) &&
1000 !(file->f_mode & FMODE_WRITE))
1001 return -EACCES;
1002
1003 if (IS_APPEND(file_inode(file)) &&
1004 (file->f_mode & FMODE_WRITE))
1005 return -EACCES;
1006
1007 if (locks_verify_locked(file))
1008 return -EAGAIN;
1009
1010 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1011 return -ENODEV;
1012
1013 /* we mustn't privatise shared mappings */
1014 capabilities &= ~BDI_CAP_MAP_COPY;
1015 } else {
1016 /* we're going to read the file into private memory we
1017 * allocate */
1018 if (!(capabilities & BDI_CAP_MAP_COPY))
1019 return -ENODEV;
1020
1021 /* we don't permit a private writable mapping to be
1022 * shared with the backing device */
1023 if (prot & PROT_WRITE)
1024 capabilities &= ~BDI_CAP_MAP_DIRECT;
1025 }
1026
1027 if (capabilities & BDI_CAP_MAP_DIRECT) {
1028 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
1029 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
1030 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
1031 ) {
1032 capabilities &= ~BDI_CAP_MAP_DIRECT;
1033 if (flags & MAP_SHARED) {
1034 printk(KERN_WARNING
1035 "MAP_SHARED not completely supported on !MMU\n");
1036 return -EINVAL;
1037 }
1038 }
1039 }
1040
1041 /* handle executable mappings and implied executable
1042 * mappings */
1043 if (file->f_path.mnt->mnt_flags & MNT_NOEXEC) {
1044 if (prot & PROT_EXEC)
1045 return -EPERM;
1046 } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
1047 /* handle implication of PROT_EXEC by PROT_READ */
1048 if (current->personality & READ_IMPLIES_EXEC) {
1049 if (capabilities & BDI_CAP_EXEC_MAP)
1050 prot |= PROT_EXEC;
1051 }
1052 } else if ((prot & PROT_READ) &&
1053 (prot & PROT_EXEC) &&
1054 !(capabilities & BDI_CAP_EXEC_MAP)
1055 ) {
1056 /* backing file is not executable, try to copy */
1057 capabilities &= ~BDI_CAP_MAP_DIRECT;
1058 }
1059 } else {
1060 /* anonymous mappings are always memory backed and can be
1061 * privately mapped
1062 */
1063 capabilities = BDI_CAP_MAP_COPY;
1064
1065 /* handle PROT_EXEC implication by PROT_READ */
1066 if ((prot & PROT_READ) &&
1067 (current->personality & READ_IMPLIES_EXEC))
1068 prot |= PROT_EXEC;
1069 }
1070
1071 /* allow the security API to have its say */
1072 ret = security_mmap_addr(addr);
1073 if (ret < 0)
1074 return ret;
1075
1076 /* looks okay */
1077 *_capabilities = capabilities;
1078 return 0;
1079}
1080
1081/*
1082 * we've determined that we can make the mapping, now translate what we
1083 * now know into VMA flags
1084 */
1085static unsigned long determine_vm_flags(struct file *file,
1086 unsigned long prot,
1087 unsigned long flags,
1088 unsigned long capabilities)
1089{
1090 unsigned long vm_flags;
1091
1092 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
1093 /* vm_flags |= mm->def_flags; */
1094
1095 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
1096 /* attempt to share read-only copies of mapped file chunks */
1097 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
1098 if (file && !(prot & PROT_WRITE))
1099 vm_flags |= VM_MAYSHARE;
1100 } else {
1101 /* overlay a shareable mapping on the backing device or inode
1102 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
1103 * romfs/cramfs */
1104 vm_flags |= VM_MAYSHARE | (capabilities & BDI_CAP_VMFLAGS);
1105 if (flags & MAP_SHARED)
1106 vm_flags |= VM_SHARED;
1107 }
1108
1109 /* refuse to let anyone share private mappings with this process if
1110 * it's being traced - otherwise breakpoints set in it may interfere
1111 * with another untraced process
1112 */
1113 if ((flags & MAP_PRIVATE) && current->ptrace)
1114 vm_flags &= ~VM_MAYSHARE;
1115
1116 return vm_flags;
1117}
1118
1119/*
1120 * set up a shared mapping on a file (the driver or filesystem provides and
1121 * pins the storage)
1122 */
1123static int do_mmap_shared_file(struct vm_area_struct *vma)
1124{
1125 int ret;
1126
1127 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1128 if (ret == 0) {
1129 vma->vm_region->vm_top = vma->vm_region->vm_end;
1130 return 0;
1131 }
1132 if (ret != -ENOSYS)
1133 return ret;
1134
1135 /* getting -ENOSYS indicates that direct mmap isn't possible (as
1136 * opposed to tried but failed) so we can only give a suitable error as
1137 * it's not possible to make a private copy if MAP_SHARED was given */
1138 return -ENODEV;
1139}
1140
1141/*
1142 * set up a private mapping or an anonymous shared mapping
1143 */
1144static int do_mmap_private(struct vm_area_struct *vma,
1145 struct vm_region *region,
1146 unsigned long len,
1147 unsigned long capabilities)
1148{
1149 struct page *pages;
1150 unsigned long total, point, n;
1151 void *base;
1152 int ret, order;
1153
1154 /* invoke the file's mapping function so that it can keep track of
1155 * shared mappings on devices or memory
1156 * - VM_MAYSHARE will be set if it may attempt to share
1157 */
1158 if (capabilities & BDI_CAP_MAP_DIRECT) {
1159 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
1160 if (ret == 0) {
1161 /* shouldn't return success if we're not sharing */
1162 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1163 vma->vm_region->vm_top = vma->vm_region->vm_end;
1164 return 0;
1165 }
1166 if (ret != -ENOSYS)
1167 return ret;
1168
1169 /* getting an ENOSYS error indicates that direct mmap isn't
1170 * possible (as opposed to tried but failed) so we'll try to
1171 * make a private copy of the data and map that instead */
1172 }
1173
1174
1175 /* allocate some memory to hold the mapping
1176 * - note that this may not return a page-aligned address if the object
1177 * we're allocating is smaller than a page
1178 */
1179 order = get_order(len);
1180 kdebug("alloc order %d for %lx", order, len);
1181
1182 pages = alloc_pages(GFP_KERNEL, order);
1183 if (!pages)
1184 goto enomem;
1185
1186 total = 1 << order;
1187 atomic_long_add(total, &mmap_pages_allocated);
1188
1189 point = len >> PAGE_SHIFT;
1190
1191 /* we allocated a power-of-2 sized page set, so we may want to trim off
1192 * the excess */
1193 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages) {
1194 while (total > point) {
1195 order = ilog2(total - point);
1196 n = 1 << order;
1197 kdebug("shave %lu/%lu @%lu", n, total - point, total);
1198 atomic_long_sub(n, &mmap_pages_allocated);
1199 total -= n;
1200 set_page_refcounted(pages + total);
1201 __free_pages(pages + total, order);
1202 }
1203 }
1204
1205 for (point = 1; point < total; point++)
1206 set_page_refcounted(&pages[point]);
1207
1208 base = page_address(pages);
1209 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1210 region->vm_start = (unsigned long) base;
1211 region->vm_end = region->vm_start + len;
1212 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1213
1214 vma->vm_start = region->vm_start;
1215 vma->vm_end = region->vm_start + len;
1216
1217 if (vma->vm_file) {
1218 /* read the contents of a file into the copy */
1219 mm_segment_t old_fs;
1220 loff_t fpos;
1221
1222 fpos = vma->vm_pgoff;
1223 fpos <<= PAGE_SHIFT;
1224
1225 old_fs = get_fs();
1226 set_fs(KERNEL_DS);
1227 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
1228 set_fs(old_fs);
1229
1230 if (ret < 0)
1231 goto error_free;
1232
1233 /* clear the last little bit */
1234 if (ret < len)
1235 memset(base + ret, 0, len - ret);
1236
1237 }
1238
1239 return 0;
1240
1241error_free:
1242 free_page_series(region->vm_start, region->vm_top);
1243 region->vm_start = vma->vm_start = 0;
1244 region->vm_end = vma->vm_end = 0;
1245 region->vm_top = 0;
1246 return ret;
1247
1248enomem:
1249 printk("Allocation of length %lu from process %d (%s) failed\n",
1250 len, current->pid, current->comm);
1251 show_free_areas(0);
1252 return -ENOMEM;
1253}
1254
1255/*
1256 * handle mapping creation for uClinux
1257 */
1258unsigned long do_mmap_pgoff(struct file *file,
1259 unsigned long addr,
1260 unsigned long len,
1261 unsigned long prot,
1262 unsigned long flags,
1263 unsigned long pgoff,
1264 unsigned long *populate)
1265{
1266 struct vm_area_struct *vma;
1267 struct vm_region *region;
1268 struct rb_node *rb;
1269 unsigned long capabilities, vm_flags, result;
1270 int ret;
1271
1272 kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
1273
1274 *populate = 0;
1275
1276 /* decide whether we should attempt the mapping, and if so what sort of
1277 * mapping */
1278 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1279 &capabilities);
1280 if (ret < 0) {
1281 kleave(" = %d [val]", ret);
1282 return ret;
1283 }
1284
1285 /* we ignore the address hint */
1286 addr = 0;
1287 len = PAGE_ALIGN(len);
1288
1289 /* we've determined that we can make the mapping, now translate what we
1290 * now know into VMA flags */
1291 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
1292
1293 /* we're going to need to record the mapping */
1294 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1295 if (!region)
1296 goto error_getting_region;
1297
1298 vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
1299 if (!vma)
1300 goto error_getting_vma;
1301
1302 region->vm_usage = 1;
1303 region->vm_flags = vm_flags;
1304 region->vm_pgoff = pgoff;
1305
1306 INIT_LIST_HEAD(&vma->anon_vma_chain);
1307 vma->vm_flags = vm_flags;
1308 vma->vm_pgoff = pgoff;
1309
1310 if (file) {
1311 region->vm_file = get_file(file);
1312 vma->vm_file = get_file(file);
1313 }
1314
1315 down_write(&nommu_region_sem);
1316
1317 /* if we want to share, we need to check for regions created by other
1318 * mmap() calls that overlap with our proposed mapping
1319 * - we can only share with a superset match on most regular files
1320 * - shared mappings on character devices and memory backed files are
1321 * permitted to overlap inexactly as far as we are concerned for in
1322 * these cases, sharing is handled in the driver or filesystem rather
1323 * than here
1324 */
1325 if (vm_flags & VM_MAYSHARE) {
1326 struct vm_region *pregion;
1327 unsigned long pglen, rpglen, pgend, rpgend, start;
1328
1329 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1330 pgend = pgoff + pglen;
1331
1332 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1333 pregion = rb_entry(rb, struct vm_region, vm_rb);
1334
1335 if (!(pregion->vm_flags & VM_MAYSHARE))
1336 continue;
1337
1338 /* search for overlapping mappings on the same file */
1339 if (file_inode(pregion->vm_file) !=
1340 file_inode(file))
1341 continue;
1342
1343 if (pregion->vm_pgoff >= pgend)
1344 continue;
1345
1346 rpglen = pregion->vm_end - pregion->vm_start;
1347 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1348 rpgend = pregion->vm_pgoff + rpglen;
1349 if (pgoff >= rpgend)
1350 continue;
1351
1352 /* handle inexactly overlapping matches between
1353 * mappings */
1354 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1355 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1356 /* new mapping is not a subset of the region */
1357 if (!(capabilities & BDI_CAP_MAP_DIRECT))
1358 goto sharing_violation;
1359 continue;
1360 }
1361
1362 /* we've found a region we can share */
1363 pregion->vm_usage++;
1364 vma->vm_region = pregion;
1365 start = pregion->vm_start;
1366 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1367 vma->vm_start = start;
1368 vma->vm_end = start + len;
1369
1370 if (pregion->vm_flags & VM_MAPPED_COPY) {
1371 kdebug("share copy");
1372 vma->vm_flags |= VM_MAPPED_COPY;
1373 } else {
1374 kdebug("share mmap");
1375 ret = do_mmap_shared_file(vma);
1376 if (ret < 0) {
1377 vma->vm_region = NULL;
1378 vma->vm_start = 0;
1379 vma->vm_end = 0;
1380 pregion->vm_usage--;
1381 pregion = NULL;
1382 goto error_just_free;
1383 }
1384 }
1385 fput(region->vm_file);
1386 kmem_cache_free(vm_region_jar, region);
1387 region = pregion;
1388 result = start;
1389 goto share;
1390 }
1391
1392 /* obtain the address at which to make a shared mapping
1393 * - this is the hook for quasi-memory character devices to
1394 * tell us the location of a shared mapping
1395 */
1396 if (capabilities & BDI_CAP_MAP_DIRECT) {
1397 addr = file->f_op->get_unmapped_area(file, addr, len,
1398 pgoff, flags);
1399 if (IS_ERR_VALUE(addr)) {
1400 ret = addr;
1401 if (ret != -ENOSYS)
1402 goto error_just_free;
1403
1404 /* the driver refused to tell us where to site
1405 * the mapping so we'll have to attempt to copy
1406 * it */
1407 ret = -ENODEV;
1408 if (!(capabilities & BDI_CAP_MAP_COPY))
1409 goto error_just_free;
1410
1411 capabilities &= ~BDI_CAP_MAP_DIRECT;
1412 } else {
1413 vma->vm_start = region->vm_start = addr;
1414 vma->vm_end = region->vm_end = addr + len;
1415 }
1416 }
1417 }
1418
1419 vma->vm_region = region;
1420
1421 /* set up the mapping
1422 * - the region is filled in if BDI_CAP_MAP_DIRECT is still set
1423 */
1424 if (file && vma->vm_flags & VM_SHARED)
1425 ret = do_mmap_shared_file(vma);
1426 else
1427 ret = do_mmap_private(vma, region, len, capabilities);
1428 if (ret < 0)
1429 goto error_just_free;
1430 add_nommu_region(region);
1431
1432 /* clear anonymous mappings that don't ask for uninitialized data */
1433 if (!vma->vm_file && !(flags & MAP_UNINITIALIZED))
1434 memset((void *)region->vm_start, 0,
1435 region->vm_end - region->vm_start);
1436
1437 /* okay... we have a mapping; now we have to register it */
1438 result = vma->vm_start;
1439
1440 current->mm->total_vm += len >> PAGE_SHIFT;
1441
1442share:
1443 add_vma_to_mm(current->mm, vma);
1444
1445 /* we flush the region from the icache only when the first executable
1446 * mapping of it is made */
1447 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1448 flush_icache_range(region->vm_start, region->vm_end);
1449 region->vm_icache_flushed = true;
1450 }
1451
1452 up_write(&nommu_region_sem);
1453
1454 kleave(" = %lx", result);
1455 return result;
1456
1457error_just_free:
1458 up_write(&nommu_region_sem);
1459error:
1460 if (region->vm_file)
1461 fput(region->vm_file);
1462 kmem_cache_free(vm_region_jar, region);
1463 if (vma->vm_file)
1464 fput(vma->vm_file);
1465 kmem_cache_free(vm_area_cachep, vma);
1466 kleave(" = %d", ret);
1467 return ret;
1468
1469sharing_violation:
1470 up_write(&nommu_region_sem);
1471 printk(KERN_WARNING "Attempt to share mismatched mappings\n");
1472 ret = -EINVAL;
1473 goto error;
1474
1475error_getting_vma:
1476 kmem_cache_free(vm_region_jar, region);
1477 printk(KERN_WARNING "Allocation of vma for %lu byte allocation"
1478 " from process %d failed\n",
1479 len, current->pid);
1480 show_free_areas(0);
1481 return -ENOMEM;
1482
1483error_getting_region:
1484 printk(KERN_WARNING "Allocation of vm region for %lu byte allocation"
1485 " from process %d failed\n",
1486 len, current->pid);
1487 show_free_areas(0);
1488 return -ENOMEM;
1489}
1490
1491SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1492 unsigned long, prot, unsigned long, flags,
1493 unsigned long, fd, unsigned long, pgoff)
1494{
1495 struct file *file = NULL;
1496 unsigned long retval = -EBADF;
1497
1498 audit_mmap_fd(fd, flags);
1499 if (!(flags & MAP_ANONYMOUS)) {
1500 file = fget(fd);
1501 if (!file)
1502 goto out;
1503 }
1504
1505 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1506
1507 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1508
1509 if (file)
1510 fput(file);
1511out:
1512 return retval;
1513}
1514
1515#ifdef __ARCH_WANT_SYS_OLD_MMAP
1516struct mmap_arg_struct {
1517 unsigned long addr;
1518 unsigned long len;
1519 unsigned long prot;
1520 unsigned long flags;
1521 unsigned long fd;
1522 unsigned long offset;
1523};
1524
1525SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1526{
1527 struct mmap_arg_struct a;
1528
1529 if (copy_from_user(&a, arg, sizeof(a)))
1530 return -EFAULT;
1531 if (a.offset & ~PAGE_MASK)
1532 return -EINVAL;
1533
1534 return sys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1535 a.offset >> PAGE_SHIFT);
1536}
1537#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1538
1539/*
1540 * split a vma into two pieces at address 'addr', a new vma is allocated either
1541 * for the first part or the tail.
1542 */
1543int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1544 unsigned long addr, int new_below)
1545{
1546 struct vm_area_struct *new;
1547 struct vm_region *region;
1548 unsigned long npages;
1549
1550 kenter("");
1551
1552 /* we're only permitted to split anonymous regions (these should have
1553 * only a single usage on the region) */
1554 if (vma->vm_file)
1555 return -ENOMEM;
1556
1557 if (mm->map_count >= sysctl_max_map_count)
1558 return -ENOMEM;
1559
1560 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1561 if (!region)
1562 return -ENOMEM;
1563
1564 new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1565 if (!new) {
1566 kmem_cache_free(vm_region_jar, region);
1567 return -ENOMEM;
1568 }
1569
1570 /* most fields are the same, copy all, and then fixup */
1571 *new = *vma;
1572 *region = *vma->vm_region;
1573 new->vm_region = region;
1574
1575 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1576
1577 if (new_below) {
1578 region->vm_top = region->vm_end = new->vm_end = addr;
1579 } else {
1580 region->vm_start = new->vm_start = addr;
1581 region->vm_pgoff = new->vm_pgoff += npages;
1582 }
1583
1584 if (new->vm_ops && new->vm_ops->open)
1585 new->vm_ops->open(new);
1586
1587 delete_vma_from_mm(vma);
1588 down_write(&nommu_region_sem);
1589 delete_nommu_region(vma->vm_region);
1590 if (new_below) {
1591 vma->vm_region->vm_start = vma->vm_start = addr;
1592 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1593 } else {
1594 vma->vm_region->vm_end = vma->vm_end = addr;
1595 vma->vm_region->vm_top = addr;
1596 }
1597 add_nommu_region(vma->vm_region);
1598 add_nommu_region(new->vm_region);
1599 up_write(&nommu_region_sem);
1600 add_vma_to_mm(mm, vma);
1601 add_vma_to_mm(mm, new);
1602 return 0;
1603}
1604
1605/*
1606 * shrink a VMA by removing the specified chunk from either the beginning or
1607 * the end
1608 */
1609static int shrink_vma(struct mm_struct *mm,
1610 struct vm_area_struct *vma,
1611 unsigned long from, unsigned long to)
1612{
1613 struct vm_region *region;
1614
1615 kenter("");
1616
1617 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1618 * and list */
1619 delete_vma_from_mm(vma);
1620 if (from > vma->vm_start)
1621 vma->vm_end = from;
1622 else
1623 vma->vm_start = to;
1624 add_vma_to_mm(mm, vma);
1625
1626 /* cut the backing region down to size */
1627 region = vma->vm_region;
1628 BUG_ON(region->vm_usage != 1);
1629
1630 down_write(&nommu_region_sem);
1631 delete_nommu_region(region);
1632 if (from > region->vm_start) {
1633 to = region->vm_top;
1634 region->vm_top = region->vm_end = from;
1635 } else {
1636 region->vm_start = to;
1637 }
1638 add_nommu_region(region);
1639 up_write(&nommu_region_sem);
1640
1641 free_page_series(from, to);
1642 return 0;
1643}
1644
1645/*
1646 * release a mapping
1647 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1648 * VMA, though it need not cover the whole VMA
1649 */
1650int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
1651{
1652 struct vm_area_struct *vma;
1653 unsigned long end;
1654 int ret;
1655
1656 kenter(",%lx,%zx", start, len);
1657
1658 len = PAGE_ALIGN(len);
1659 if (len == 0)
1660 return -EINVAL;
1661
1662 end = start + len;
1663
1664 /* find the first potentially overlapping VMA */
1665 vma = find_vma(mm, start);
1666 if (!vma) {
1667 static int limit;
1668 if (limit < 5) {
1669 printk(KERN_WARNING
1670 "munmap of memory not mmapped by process %d"
1671 " (%s): 0x%lx-0x%lx\n",
1672 current->pid, current->comm,
1673 start, start + len - 1);
1674 limit++;
1675 }
1676 return -EINVAL;
1677 }
1678
1679 /* we're allowed to split an anonymous VMA but not a file-backed one */
1680 if (vma->vm_file) {
1681 do {
1682 if (start > vma->vm_start) {
1683 kleave(" = -EINVAL [miss]");
1684 return -EINVAL;
1685 }
1686 if (end == vma->vm_end)
1687 goto erase_whole_vma;
1688 vma = vma->vm_next;
1689 } while (vma);
1690 kleave(" = -EINVAL [split file]");
1691 return -EINVAL;
1692 } else {
1693 /* the chunk must be a subset of the VMA found */
1694 if (start == vma->vm_start && end == vma->vm_end)
1695 goto erase_whole_vma;
1696 if (start < vma->vm_start || end > vma->vm_end) {
1697 kleave(" = -EINVAL [superset]");
1698 return -EINVAL;
1699 }
1700 if (start & ~PAGE_MASK) {
1701 kleave(" = -EINVAL [unaligned start]");
1702 return -EINVAL;
1703 }
1704 if (end != vma->vm_end && end & ~PAGE_MASK) {
1705 kleave(" = -EINVAL [unaligned split]");
1706 return -EINVAL;
1707 }
1708 if (start != vma->vm_start && end != vma->vm_end) {
1709 ret = split_vma(mm, vma, start, 1);
1710 if (ret < 0) {
1711 kleave(" = %d [split]", ret);
1712 return ret;
1713 }
1714 }
1715 return shrink_vma(mm, vma, start, end);
1716 }
1717
1718erase_whole_vma:
1719 delete_vma_from_mm(vma);
1720 delete_vma(mm, vma);
1721 kleave(" = 0");
1722 return 0;
1723}
1724EXPORT_SYMBOL(do_munmap);
1725
1726int vm_munmap(unsigned long addr, size_t len)
1727{
1728 struct mm_struct *mm = current->mm;
1729 int ret;
1730
1731 down_write(&mm->mmap_sem);
1732 ret = do_munmap(mm, addr, len);
1733 up_write(&mm->mmap_sem);
1734 return ret;
1735}
1736EXPORT_SYMBOL(vm_munmap);
1737
1738SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1739{
1740 return vm_munmap(addr, len);
1741}
1742
1743/*
1744 * release all the mappings made in a process's VM space
1745 */
1746void exit_mmap(struct mm_struct *mm)
1747{
1748 struct vm_area_struct *vma;
1749
1750 if (!mm)
1751 return;
1752
1753 kenter("");
1754
1755 mm->total_vm = 0;
1756
1757 while ((vma = mm->mmap)) {
1758 mm->mmap = vma->vm_next;
1759 delete_vma_from_mm(vma);
1760 delete_vma(mm, vma);
1761 cond_resched();
1762 }
1763
1764 kleave("");
1765}
1766
1767unsigned long vm_brk(unsigned long addr, unsigned long len)
1768{
1769 return -ENOMEM;
1770}
1771
1772/*
1773 * expand (or shrink) an existing mapping, potentially moving it at the same
1774 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1775 *
1776 * under NOMMU conditions, we only permit changing a mapping's size, and only
1777 * as long as it stays within the region allocated by do_mmap_private() and the
1778 * block is not shareable
1779 *
1780 * MREMAP_FIXED is not supported under NOMMU conditions
1781 */
1782static unsigned long do_mremap(unsigned long addr,
1783 unsigned long old_len, unsigned long new_len,
1784 unsigned long flags, unsigned long new_addr)
1785{
1786 struct vm_area_struct *vma;
1787
1788 /* insanity checks first */
1789 old_len = PAGE_ALIGN(old_len);
1790 new_len = PAGE_ALIGN(new_len);
1791 if (old_len == 0 || new_len == 0)
1792 return (unsigned long) -EINVAL;
1793
1794 if (addr & ~PAGE_MASK)
1795 return -EINVAL;
1796
1797 if (flags & MREMAP_FIXED && new_addr != addr)
1798 return (unsigned long) -EINVAL;
1799
1800 vma = find_vma_exact(current->mm, addr, old_len);
1801 if (!vma)
1802 return (unsigned long) -EINVAL;
1803
1804 if (vma->vm_end != vma->vm_start + old_len)
1805 return (unsigned long) -EFAULT;
1806
1807 if (vma->vm_flags & VM_MAYSHARE)
1808 return (unsigned long) -EPERM;
1809
1810 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1811 return (unsigned long) -ENOMEM;
1812
1813 /* all checks complete - do it */
1814 vma->vm_end = vma->vm_start + new_len;
1815 return vma->vm_start;
1816}
1817
1818SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1819 unsigned long, new_len, unsigned long, flags,
1820 unsigned long, new_addr)
1821{
1822 unsigned long ret;
1823
1824 down_write(¤t->mm->mmap_sem);
1825 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1826 up_write(¤t->mm->mmap_sem);
1827 return ret;
1828}
1829
1830struct page *follow_page_mask(struct vm_area_struct *vma,
1831 unsigned long address, unsigned int flags,
1832 unsigned int *page_mask)
1833{
1834 *page_mask = 0;
1835 return NULL;
1836}
1837
1838int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1839 unsigned long pfn, unsigned long size, pgprot_t prot)
1840{
1841 if (addr != (pfn << PAGE_SHIFT))
1842 return -EINVAL;
1843
1844 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1845 return 0;
1846}
1847EXPORT_SYMBOL(remap_pfn_range);
1848
1849int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1850{
1851 unsigned long pfn = start >> PAGE_SHIFT;
1852 unsigned long vm_len = vma->vm_end - vma->vm_start;
1853
1854 pfn += vma->vm_pgoff;
1855 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1856}
1857EXPORT_SYMBOL(vm_iomap_memory);
1858
1859int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1860 unsigned long pgoff)
1861{
1862 unsigned int size = vma->vm_end - vma->vm_start;
1863
1864 if (!(vma->vm_flags & VM_USERMAP))
1865 return -EINVAL;
1866
1867 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1868 vma->vm_end = vma->vm_start + size;
1869
1870 return 0;
1871}
1872EXPORT_SYMBOL(remap_vmalloc_range);
1873
1874unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1875 unsigned long len, unsigned long pgoff, unsigned long flags)
1876{
1877 return -ENOMEM;
1878}
1879
1880void unmap_mapping_range(struct address_space *mapping,
1881 loff_t const holebegin, loff_t const holelen,
1882 int even_cows)
1883{
1884}
1885EXPORT_SYMBOL(unmap_mapping_range);
1886
1887/*
1888 * Check that a process has enough memory to allocate a new virtual
1889 * mapping. 0 means there is enough memory for the allocation to
1890 * succeed and -ENOMEM implies there is not.
1891 *
1892 * We currently support three overcommit policies, which are set via the
1893 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1894 *
1895 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1896 * Additional code 2002 Jul 20 by Robert Love.
1897 *
1898 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1899 *
1900 * Note this is a helper function intended to be used by LSMs which
1901 * wish to use this logic.
1902 */
1903int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
1904{
1905 unsigned long free, allowed, reserve;
1906
1907 vm_acct_memory(pages);
1908
1909 /*
1910 * Sometimes we want to use more memory than we have
1911 */
1912 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1913 return 0;
1914
1915 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1916 free = global_page_state(NR_FREE_PAGES);
1917 free += global_page_state(NR_FILE_PAGES);
1918
1919 /*
1920 * shmem pages shouldn't be counted as free in this
1921 * case, they can't be purged, only swapped out, and
1922 * that won't affect the overall amount of available
1923 * memory in the system.
1924 */
1925 free -= global_page_state(NR_SHMEM);
1926
1927 free += get_nr_swap_pages();
1928
1929 /*
1930 * Any slabs which are created with the
1931 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1932 * which are reclaimable, under pressure. The dentry
1933 * cache and most inode caches should fall into this
1934 */
1935 free += global_page_state(NR_SLAB_RECLAIMABLE);
1936
1937 /*
1938 * Leave reserved pages. The pages are not for anonymous pages.
1939 */
1940 if (free <= totalreserve_pages)
1941 goto error;
1942 else
1943 free -= totalreserve_pages;
1944
1945 /*
1946 * Reserve some for root
1947 */
1948 if (!cap_sys_admin)
1949 free -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
1950
1951 if (free > pages)
1952 return 0;
1953
1954 goto error;
1955 }
1956
1957 allowed = vm_commit_limit();
1958 /*
1959 * Reserve some 3% for root
1960 */
1961 if (!cap_sys_admin)
1962 allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10);
1963
1964 /*
1965 * Don't let a single process grow so big a user can't recover
1966 */
1967 if (mm) {
1968 reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10);
1969 allowed -= min(mm->total_vm / 32, reserve);
1970 }
1971
1972 if (percpu_counter_read_positive(&vm_committed_as) < allowed)
1973 return 0;
1974
1975error:
1976 vm_unacct_memory(pages);
1977
1978 return -ENOMEM;
1979}
1980
1981int in_gate_area_no_mm(unsigned long addr)
1982{
1983 return 0;
1984}
1985
1986int filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
1987{
1988 BUG();
1989 return 0;
1990}
1991EXPORT_SYMBOL(filemap_fault);
1992
1993void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf)
1994{
1995 BUG();
1996}
1997EXPORT_SYMBOL(filemap_map_pages);
1998
1999int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr,
2000 unsigned long size, pgoff_t pgoff)
2001{
2002 BUG();
2003 return 0;
2004}
2005EXPORT_SYMBOL(generic_file_remap_pages);
2006
2007static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
2008 unsigned long addr, void *buf, int len, int write)
2009{
2010 struct vm_area_struct *vma;
2011
2012 down_read(&mm->mmap_sem);
2013
2014 /* the access must start within one of the target process's mappings */
2015 vma = find_vma(mm, addr);
2016 if (vma) {
2017 /* don't overrun this mapping */
2018 if (addr + len >= vma->vm_end)
2019 len = vma->vm_end - addr;
2020
2021 /* only read or write mappings where it is permitted */
2022 if (write && vma->vm_flags & VM_MAYWRITE)
2023 copy_to_user_page(vma, NULL, addr,
2024 (void *) addr, buf, len);
2025 else if (!write && vma->vm_flags & VM_MAYREAD)
2026 copy_from_user_page(vma, NULL, addr,
2027 buf, (void *) addr, len);
2028 else
2029 len = 0;
2030 } else {
2031 len = 0;
2032 }
2033
2034 up_read(&mm->mmap_sem);
2035
2036 return len;
2037}
2038
2039/**
2040 * @access_remote_vm - access another process' address space
2041 * @mm: the mm_struct of the target address space
2042 * @addr: start address to access
2043 * @buf: source or destination buffer
2044 * @len: number of bytes to transfer
2045 * @write: whether the access is a write
2046 *
2047 * The caller must hold a reference on @mm.
2048 */
2049int access_remote_vm(struct mm_struct *mm, unsigned long addr,
2050 void *buf, int len, int write)
2051{
2052 return __access_remote_vm(NULL, mm, addr, buf, len, write);
2053}
2054
2055/*
2056 * Access another process' address space.
2057 * - source/target buffer must be kernel space
2058 */
2059int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2060{
2061 struct mm_struct *mm;
2062
2063 if (addr + len < addr)
2064 return 0;
2065
2066 mm = get_task_mm(tsk);
2067 if (!mm)
2068 return 0;
2069
2070 len = __access_remote_vm(tsk, mm, addr, buf, len, write);
2071
2072 mmput(mm);
2073 return len;
2074}
2075
2076/**
2077 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
2078 * @inode: The inode to check
2079 * @size: The current filesize of the inode
2080 * @newsize: The proposed filesize of the inode
2081 *
2082 * Check the shared mappings on an inode on behalf of a shrinking truncate to
2083 * make sure that that any outstanding VMAs aren't broken and then shrink the
2084 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
2085 * automatically grant mappings that are too large.
2086 */
2087int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
2088 size_t newsize)
2089{
2090 struct vm_area_struct *vma;
2091 struct vm_region *region;
2092 pgoff_t low, high;
2093 size_t r_size, r_top;
2094
2095 low = newsize >> PAGE_SHIFT;
2096 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
2097
2098 down_write(&nommu_region_sem);
2099 mutex_lock(&inode->i_mapping->i_mmap_mutex);
2100
2101 /* search for VMAs that fall within the dead zone */
2102 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
2103 /* found one - only interested if it's shared out of the page
2104 * cache */
2105 if (vma->vm_flags & VM_SHARED) {
2106 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
2107 up_write(&nommu_region_sem);
2108 return -ETXTBSY; /* not quite true, but near enough */
2109 }
2110 }
2111
2112 /* reduce any regions that overlap the dead zone - if in existence,
2113 * these will be pointed to by VMAs that don't overlap the dead zone
2114 *
2115 * we don't check for any regions that start beyond the EOF as there
2116 * shouldn't be any
2117 */
2118 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap,
2119 0, ULONG_MAX) {
2120 if (!(vma->vm_flags & VM_SHARED))
2121 continue;
2122
2123 region = vma->vm_region;
2124 r_size = region->vm_top - region->vm_start;
2125 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
2126
2127 if (r_top > newsize) {
2128 region->vm_top -= r_top - newsize;
2129 if (region->vm_end > region->vm_top)
2130 region->vm_end = region->vm_top;
2131 }
2132 }
2133
2134 mutex_unlock(&inode->i_mapping->i_mmap_mutex);
2135 up_write(&nommu_region_sem);
2136 return 0;
2137}
2138
2139/*
2140 * Initialise sysctl_user_reserve_kbytes.
2141 *
2142 * This is intended to prevent a user from starting a single memory hogging
2143 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
2144 * mode.
2145 *
2146 * The default value is min(3% of free memory, 128MB)
2147 * 128MB is enough to recover with sshd/login, bash, and top/kill.
2148 */
2149static int __meminit init_user_reserve(void)
2150{
2151 unsigned long free_kbytes;
2152
2153 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
2154
2155 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
2156 return 0;
2157}
2158module_init(init_user_reserve)
2159
2160/*
2161 * Initialise sysctl_admin_reserve_kbytes.
2162 *
2163 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
2164 * to log in and kill a memory hogging process.
2165 *
2166 * Systems with more than 256MB will reserve 8MB, enough to recover
2167 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
2168 * only reserve 3% of free pages by default.
2169 */
2170static int __meminit init_admin_reserve(void)
2171{
2172 unsigned long free_kbytes;
2173
2174 free_kbytes = global_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
2175
2176 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
2177 return 0;
2178}
2179module_init(init_admin_reserve)