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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/nommu-mmap.txt
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, pgprot_t prot)
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_flags(unsigned long size, int node, gfp_t flags)
154{
155 return __vmalloc(size, flags, PAGE_KERNEL);
156}
157
158void *vmalloc_user(unsigned long size)
159{
160 void *ret;
161
162 ret = __vmalloc(size, GFP_KERNEL | __GFP_ZERO, PAGE_KERNEL);
163 if (ret) {
164 struct vm_area_struct *vma;
165
166 down_write(¤t->mm->mmap_sem);
167 vma = find_vma(current->mm, (unsigned long)ret);
168 if (vma)
169 vma->vm_flags |= VM_USERMAP;
170 up_write(¤t->mm->mmap_sem);
171 }
172
173 return ret;
174}
175EXPORT_SYMBOL(vmalloc_user);
176
177struct page *vmalloc_to_page(const void *addr)
178{
179 return virt_to_page(addr);
180}
181EXPORT_SYMBOL(vmalloc_to_page);
182
183unsigned long vmalloc_to_pfn(const void *addr)
184{
185 return page_to_pfn(virt_to_page(addr));
186}
187EXPORT_SYMBOL(vmalloc_to_pfn);
188
189long vread(char *buf, char *addr, unsigned long count)
190{
191 /* Don't allow overflow */
192 if ((unsigned long) buf + count < count)
193 count = -(unsigned long) buf;
194
195 memcpy(buf, addr, count);
196 return count;
197}
198
199long vwrite(char *buf, char *addr, unsigned long count)
200{
201 /* Don't allow overflow */
202 if ((unsigned long) addr + count < count)
203 count = -(unsigned long) addr;
204
205 memcpy(addr, buf, count);
206 return count;
207}
208
209/*
210 * vmalloc - allocate virtually contiguous memory
211 *
212 * @size: allocation size
213 *
214 * Allocate enough pages to cover @size from the page level
215 * allocator and map them into contiguous kernel virtual space.
216 *
217 * For tight control over page level allocator and protection flags
218 * use __vmalloc() instead.
219 */
220void *vmalloc(unsigned long size)
221{
222 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
223}
224EXPORT_SYMBOL(vmalloc);
225
226/*
227 * vzalloc - allocate virtually contiguous memory with zero fill
228 *
229 * @size: allocation size
230 *
231 * Allocate enough pages to cover @size from the page level
232 * allocator and map them into contiguous kernel virtual space.
233 * The memory allocated is set to zero.
234 *
235 * For tight control over page level allocator and protection flags
236 * use __vmalloc() instead.
237 */
238void *vzalloc(unsigned long size)
239{
240 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
241 PAGE_KERNEL);
242}
243EXPORT_SYMBOL(vzalloc);
244
245/**
246 * vmalloc_node - allocate memory on a specific node
247 * @size: allocation size
248 * @node: numa node
249 *
250 * Allocate enough pages to cover @size from the page level
251 * allocator and map them into contiguous kernel virtual space.
252 *
253 * For tight control over page level allocator and protection flags
254 * use __vmalloc() instead.
255 */
256void *vmalloc_node(unsigned long size, int node)
257{
258 return vmalloc(size);
259}
260EXPORT_SYMBOL(vmalloc_node);
261
262/**
263 * vzalloc_node - allocate memory on a specific node with zero fill
264 * @size: allocation size
265 * @node: numa node
266 *
267 * Allocate enough pages to cover @size from the page level
268 * allocator and map them into contiguous kernel virtual space.
269 * The memory allocated is set to zero.
270 *
271 * For tight control over page level allocator and protection flags
272 * use __vmalloc() instead.
273 */
274void *vzalloc_node(unsigned long size, int node)
275{
276 return vzalloc(size);
277}
278EXPORT_SYMBOL(vzalloc_node);
279
280/**
281 * vmalloc_exec - allocate virtually contiguous, executable memory
282 * @size: allocation size
283 *
284 * Kernel-internal function to allocate enough pages to cover @size
285 * the page level allocator and map them into contiguous and
286 * executable kernel virtual space.
287 *
288 * For tight control over page level allocator and protection flags
289 * use __vmalloc() instead.
290 */
291
292void *vmalloc_exec(unsigned long size)
293{
294 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC);
295}
296
297/**
298 * vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
299 * @size: allocation size
300 *
301 * Allocate enough 32bit PA addressable pages to cover @size from the
302 * page level allocator and map them into contiguous kernel virtual space.
303 */
304void *vmalloc_32(unsigned long size)
305{
306 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
307}
308EXPORT_SYMBOL(vmalloc_32);
309
310/**
311 * vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
312 * @size: allocation size
313 *
314 * The resulting memory area is 32bit addressable and zeroed so it can be
315 * mapped to userspace without leaking data.
316 *
317 * VM_USERMAP is set on the corresponding VMA so that subsequent calls to
318 * remap_vmalloc_range() are permissible.
319 */
320void *vmalloc_32_user(unsigned long size)
321{
322 /*
323 * We'll have to sort out the ZONE_DMA bits for 64-bit,
324 * but for now this can simply use vmalloc_user() directly.
325 */
326 return vmalloc_user(size);
327}
328EXPORT_SYMBOL(vmalloc_32_user);
329
330void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
331{
332 BUG();
333 return NULL;
334}
335EXPORT_SYMBOL(vmap);
336
337void vunmap(const void *addr)
338{
339 BUG();
340}
341EXPORT_SYMBOL(vunmap);
342
343void *vm_map_ram(struct page **pages, unsigned int count, int node, pgprot_t prot)
344{
345 BUG();
346 return NULL;
347}
348EXPORT_SYMBOL(vm_map_ram);
349
350void vm_unmap_ram(const void *mem, unsigned int count)
351{
352 BUG();
353}
354EXPORT_SYMBOL(vm_unmap_ram);
355
356void vm_unmap_aliases(void)
357{
358}
359EXPORT_SYMBOL_GPL(vm_unmap_aliases);
360
361/*
362 * Implement a stub for vmalloc_sync_all() if the architecture chose not to
363 * have one.
364 */
365void __weak vmalloc_sync_all(void)
366{
367}
368
369struct vm_struct *alloc_vm_area(size_t size, pte_t **ptes)
370{
371 BUG();
372 return NULL;
373}
374EXPORT_SYMBOL_GPL(alloc_vm_area);
375
376void free_vm_area(struct vm_struct *area)
377{
378 BUG();
379}
380EXPORT_SYMBOL_GPL(free_vm_area);
381
382int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
383 struct page *page)
384{
385 return -EINVAL;
386}
387EXPORT_SYMBOL(vm_insert_page);
388
389int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
390 unsigned long num)
391{
392 return -EINVAL;
393}
394EXPORT_SYMBOL(vm_map_pages);
395
396int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
397 unsigned long num)
398{
399 return -EINVAL;
400}
401EXPORT_SYMBOL(vm_map_pages_zero);
402
403/*
404 * sys_brk() for the most part doesn't need the global kernel
405 * lock, except when an application is doing something nasty
406 * like trying to un-brk an area that has already been mapped
407 * to a regular file. in this case, the unmapping will need
408 * to invoke file system routines that need the global lock.
409 */
410SYSCALL_DEFINE1(brk, unsigned long, brk)
411{
412 struct mm_struct *mm = current->mm;
413
414 if (brk < mm->start_brk || brk > mm->context.end_brk)
415 return mm->brk;
416
417 if (mm->brk == brk)
418 return mm->brk;
419
420 /*
421 * Always allow shrinking brk
422 */
423 if (brk <= mm->brk) {
424 mm->brk = brk;
425 return brk;
426 }
427
428 /*
429 * Ok, looks good - let it rip.
430 */
431 flush_icache_range(mm->brk, brk);
432 return mm->brk = brk;
433}
434
435/*
436 * initialise the percpu counter for VM and region record slabs
437 */
438void __init mmap_init(void)
439{
440 int ret;
441
442 ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
443 VM_BUG_ON(ret);
444 vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
445}
446
447/*
448 * validate the region tree
449 * - the caller must hold the region lock
450 */
451#ifdef CONFIG_DEBUG_NOMMU_REGIONS
452static noinline void validate_nommu_regions(void)
453{
454 struct vm_region *region, *last;
455 struct rb_node *p, *lastp;
456
457 lastp = rb_first(&nommu_region_tree);
458 if (!lastp)
459 return;
460
461 last = rb_entry(lastp, struct vm_region, vm_rb);
462 BUG_ON(last->vm_end <= last->vm_start);
463 BUG_ON(last->vm_top < last->vm_end);
464
465 while ((p = rb_next(lastp))) {
466 region = rb_entry(p, struct vm_region, vm_rb);
467 last = rb_entry(lastp, struct vm_region, vm_rb);
468
469 BUG_ON(region->vm_end <= region->vm_start);
470 BUG_ON(region->vm_top < region->vm_end);
471 BUG_ON(region->vm_start < last->vm_top);
472
473 lastp = p;
474 }
475}
476#else
477static void validate_nommu_regions(void)
478{
479}
480#endif
481
482/*
483 * add a region into the global tree
484 */
485static void add_nommu_region(struct vm_region *region)
486{
487 struct vm_region *pregion;
488 struct rb_node **p, *parent;
489
490 validate_nommu_regions();
491
492 parent = NULL;
493 p = &nommu_region_tree.rb_node;
494 while (*p) {
495 parent = *p;
496 pregion = rb_entry(parent, struct vm_region, vm_rb);
497 if (region->vm_start < pregion->vm_start)
498 p = &(*p)->rb_left;
499 else if (region->vm_start > pregion->vm_start)
500 p = &(*p)->rb_right;
501 else if (pregion == region)
502 return;
503 else
504 BUG();
505 }
506
507 rb_link_node(®ion->vm_rb, parent, p);
508 rb_insert_color(®ion->vm_rb, &nommu_region_tree);
509
510 validate_nommu_regions();
511}
512
513/*
514 * delete a region from the global tree
515 */
516static void delete_nommu_region(struct vm_region *region)
517{
518 BUG_ON(!nommu_region_tree.rb_node);
519
520 validate_nommu_regions();
521 rb_erase(®ion->vm_rb, &nommu_region_tree);
522 validate_nommu_regions();
523}
524
525/*
526 * free a contiguous series of pages
527 */
528static void free_page_series(unsigned long from, unsigned long to)
529{
530 for (; from < to; from += PAGE_SIZE) {
531 struct page *page = virt_to_page(from);
532
533 atomic_long_dec(&mmap_pages_allocated);
534 put_page(page);
535 }
536}
537
538/*
539 * release a reference to a region
540 * - the caller must hold the region semaphore for writing, which this releases
541 * - the region may not have been added to the tree yet, in which case vm_top
542 * will equal vm_start
543 */
544static void __put_nommu_region(struct vm_region *region)
545 __releases(nommu_region_sem)
546{
547 BUG_ON(!nommu_region_tree.rb_node);
548
549 if (--region->vm_usage == 0) {
550 if (region->vm_top > region->vm_start)
551 delete_nommu_region(region);
552 up_write(&nommu_region_sem);
553
554 if (region->vm_file)
555 fput(region->vm_file);
556
557 /* IO memory and memory shared directly out of the pagecache
558 * from ramfs/tmpfs mustn't be released here */
559 if (region->vm_flags & VM_MAPPED_COPY)
560 free_page_series(region->vm_start, region->vm_top);
561 kmem_cache_free(vm_region_jar, region);
562 } else {
563 up_write(&nommu_region_sem);
564 }
565}
566
567/*
568 * release a reference to a region
569 */
570static void put_nommu_region(struct vm_region *region)
571{
572 down_write(&nommu_region_sem);
573 __put_nommu_region(region);
574}
575
576/*
577 * add a VMA into a process's mm_struct in the appropriate place in the list
578 * and tree and add to the address space's page tree also if not an anonymous
579 * page
580 * - should be called with mm->mmap_sem held writelocked
581 */
582static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
583{
584 struct vm_area_struct *pvma, *prev;
585 struct address_space *mapping;
586 struct rb_node **p, *parent, *rb_prev;
587
588 BUG_ON(!vma->vm_region);
589
590 mm->map_count++;
591 vma->vm_mm = mm;
592
593 /* add the VMA to the mapping */
594 if (vma->vm_file) {
595 mapping = vma->vm_file->f_mapping;
596
597 i_mmap_lock_write(mapping);
598 flush_dcache_mmap_lock(mapping);
599 vma_interval_tree_insert(vma, &mapping->i_mmap);
600 flush_dcache_mmap_unlock(mapping);
601 i_mmap_unlock_write(mapping);
602 }
603
604 /* add the VMA to the tree */
605 parent = rb_prev = NULL;
606 p = &mm->mm_rb.rb_node;
607 while (*p) {
608 parent = *p;
609 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
610
611 /* sort by: start addr, end addr, VMA struct addr in that order
612 * (the latter is necessary as we may get identical VMAs) */
613 if (vma->vm_start < pvma->vm_start)
614 p = &(*p)->rb_left;
615 else if (vma->vm_start > pvma->vm_start) {
616 rb_prev = parent;
617 p = &(*p)->rb_right;
618 } else if (vma->vm_end < pvma->vm_end)
619 p = &(*p)->rb_left;
620 else if (vma->vm_end > pvma->vm_end) {
621 rb_prev = parent;
622 p = &(*p)->rb_right;
623 } else if (vma < pvma)
624 p = &(*p)->rb_left;
625 else if (vma > pvma) {
626 rb_prev = parent;
627 p = &(*p)->rb_right;
628 } else
629 BUG();
630 }
631
632 rb_link_node(&vma->vm_rb, parent, p);
633 rb_insert_color(&vma->vm_rb, &mm->mm_rb);
634
635 /* add VMA to the VMA list also */
636 prev = NULL;
637 if (rb_prev)
638 prev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
639
640 __vma_link_list(mm, vma, prev, parent);
641}
642
643/*
644 * delete a VMA from its owning mm_struct and address space
645 */
646static void delete_vma_from_mm(struct vm_area_struct *vma)
647{
648 int i;
649 struct address_space *mapping;
650 struct mm_struct *mm = vma->vm_mm;
651 struct task_struct *curr = current;
652
653 mm->map_count--;
654 for (i = 0; i < VMACACHE_SIZE; i++) {
655 /* if the vma is cached, invalidate the entire cache */
656 if (curr->vmacache.vmas[i] == vma) {
657 vmacache_invalidate(mm);
658 break;
659 }
660 }
661
662 /* remove the VMA from the mapping */
663 if (vma->vm_file) {
664 mapping = vma->vm_file->f_mapping;
665
666 i_mmap_lock_write(mapping);
667 flush_dcache_mmap_lock(mapping);
668 vma_interval_tree_remove(vma, &mapping->i_mmap);
669 flush_dcache_mmap_unlock(mapping);
670 i_mmap_unlock_write(mapping);
671 }
672
673 /* remove from the MM's tree and list */
674 rb_erase(&vma->vm_rb, &mm->mm_rb);
675
676 if (vma->vm_prev)
677 vma->vm_prev->vm_next = vma->vm_next;
678 else
679 mm->mmap = vma->vm_next;
680
681 if (vma->vm_next)
682 vma->vm_next->vm_prev = vma->vm_prev;
683}
684
685/*
686 * destroy a VMA record
687 */
688static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
689{
690 if (vma->vm_ops && vma->vm_ops->close)
691 vma->vm_ops->close(vma);
692 if (vma->vm_file)
693 fput(vma->vm_file);
694 put_nommu_region(vma->vm_region);
695 vm_area_free(vma);
696}
697
698/*
699 * look up the first VMA in which addr resides, NULL if none
700 * - should be called with mm->mmap_sem at least held readlocked
701 */
702struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
703{
704 struct vm_area_struct *vma;
705
706 /* check the cache first */
707 vma = vmacache_find(mm, addr);
708 if (likely(vma))
709 return vma;
710
711 /* trawl the list (there may be multiple mappings in which addr
712 * resides) */
713 for (vma = mm->mmap; vma; vma = vma->vm_next) {
714 if (vma->vm_start > addr)
715 return NULL;
716 if (vma->vm_end > addr) {
717 vmacache_update(addr, vma);
718 return vma;
719 }
720 }
721
722 return NULL;
723}
724EXPORT_SYMBOL(find_vma);
725
726/*
727 * find a VMA
728 * - we don't extend stack VMAs under NOMMU conditions
729 */
730struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
731{
732 return find_vma(mm, addr);
733}
734
735/*
736 * expand a stack to a given address
737 * - not supported under NOMMU conditions
738 */
739int expand_stack(struct vm_area_struct *vma, unsigned long address)
740{
741 return -ENOMEM;
742}
743
744/*
745 * look up the first VMA exactly that exactly matches addr
746 * - should be called with mm->mmap_sem at least held readlocked
747 */
748static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
749 unsigned long addr,
750 unsigned long len)
751{
752 struct vm_area_struct *vma;
753 unsigned long end = addr + len;
754
755 /* check the cache first */
756 vma = vmacache_find_exact(mm, addr, end);
757 if (vma)
758 return vma;
759
760 /* trawl the list (there may be multiple mappings in which addr
761 * resides) */
762 for (vma = mm->mmap; vma; vma = vma->vm_next) {
763 if (vma->vm_start < addr)
764 continue;
765 if (vma->vm_start > addr)
766 return NULL;
767 if (vma->vm_end == end) {
768 vmacache_update(addr, vma);
769 return vma;
770 }
771 }
772
773 return NULL;
774}
775
776/*
777 * determine whether a mapping should be permitted and, if so, what sort of
778 * mapping we're capable of supporting
779 */
780static int validate_mmap_request(struct file *file,
781 unsigned long addr,
782 unsigned long len,
783 unsigned long prot,
784 unsigned long flags,
785 unsigned long pgoff,
786 unsigned long *_capabilities)
787{
788 unsigned long capabilities, rlen;
789 int ret;
790
791 /* do the simple checks first */
792 if (flags & MAP_FIXED)
793 return -EINVAL;
794
795 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
796 (flags & MAP_TYPE) != MAP_SHARED)
797 return -EINVAL;
798
799 if (!len)
800 return -EINVAL;
801
802 /* Careful about overflows.. */
803 rlen = PAGE_ALIGN(len);
804 if (!rlen || rlen > TASK_SIZE)
805 return -ENOMEM;
806
807 /* offset overflow? */
808 if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
809 return -EOVERFLOW;
810
811 if (file) {
812 /* files must support mmap */
813 if (!file->f_op->mmap)
814 return -ENODEV;
815
816 /* work out if what we've got could possibly be shared
817 * - we support chardevs that provide their own "memory"
818 * - we support files/blockdevs that are memory backed
819 */
820 if (file->f_op->mmap_capabilities) {
821 capabilities = file->f_op->mmap_capabilities(file);
822 } else {
823 /* no explicit capabilities set, so assume some
824 * defaults */
825 switch (file_inode(file)->i_mode & S_IFMT) {
826 case S_IFREG:
827 case S_IFBLK:
828 capabilities = NOMMU_MAP_COPY;
829 break;
830
831 case S_IFCHR:
832 capabilities =
833 NOMMU_MAP_DIRECT |
834 NOMMU_MAP_READ |
835 NOMMU_MAP_WRITE;
836 break;
837
838 default:
839 return -EINVAL;
840 }
841 }
842
843 /* eliminate any capabilities that we can't support on this
844 * device */
845 if (!file->f_op->get_unmapped_area)
846 capabilities &= ~NOMMU_MAP_DIRECT;
847 if (!(file->f_mode & FMODE_CAN_READ))
848 capabilities &= ~NOMMU_MAP_COPY;
849
850 /* The file shall have been opened with read permission. */
851 if (!(file->f_mode & FMODE_READ))
852 return -EACCES;
853
854 if (flags & MAP_SHARED) {
855 /* do checks for writing, appending and locking */
856 if ((prot & PROT_WRITE) &&
857 !(file->f_mode & FMODE_WRITE))
858 return -EACCES;
859
860 if (IS_APPEND(file_inode(file)) &&
861 (file->f_mode & FMODE_WRITE))
862 return -EACCES;
863
864 if (locks_verify_locked(file))
865 return -EAGAIN;
866
867 if (!(capabilities & NOMMU_MAP_DIRECT))
868 return -ENODEV;
869
870 /* we mustn't privatise shared mappings */
871 capabilities &= ~NOMMU_MAP_COPY;
872 } else {
873 /* we're going to read the file into private memory we
874 * allocate */
875 if (!(capabilities & NOMMU_MAP_COPY))
876 return -ENODEV;
877
878 /* we don't permit a private writable mapping to be
879 * shared with the backing device */
880 if (prot & PROT_WRITE)
881 capabilities &= ~NOMMU_MAP_DIRECT;
882 }
883
884 if (capabilities & NOMMU_MAP_DIRECT) {
885 if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
886 ((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
887 ((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
888 ) {
889 capabilities &= ~NOMMU_MAP_DIRECT;
890 if (flags & MAP_SHARED) {
891 pr_warn("MAP_SHARED not completely supported on !MMU\n");
892 return -EINVAL;
893 }
894 }
895 }
896
897 /* handle executable mappings and implied executable
898 * mappings */
899 if (path_noexec(&file->f_path)) {
900 if (prot & PROT_EXEC)
901 return -EPERM;
902 } else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
903 /* handle implication of PROT_EXEC by PROT_READ */
904 if (current->personality & READ_IMPLIES_EXEC) {
905 if (capabilities & NOMMU_MAP_EXEC)
906 prot |= PROT_EXEC;
907 }
908 } else if ((prot & PROT_READ) &&
909 (prot & PROT_EXEC) &&
910 !(capabilities & NOMMU_MAP_EXEC)
911 ) {
912 /* backing file is not executable, try to copy */
913 capabilities &= ~NOMMU_MAP_DIRECT;
914 }
915 } else {
916 /* anonymous mappings are always memory backed and can be
917 * privately mapped
918 */
919 capabilities = NOMMU_MAP_COPY;
920
921 /* handle PROT_EXEC implication by PROT_READ */
922 if ((prot & PROT_READ) &&
923 (current->personality & READ_IMPLIES_EXEC))
924 prot |= PROT_EXEC;
925 }
926
927 /* allow the security API to have its say */
928 ret = security_mmap_addr(addr);
929 if (ret < 0)
930 return ret;
931
932 /* looks okay */
933 *_capabilities = capabilities;
934 return 0;
935}
936
937/*
938 * we've determined that we can make the mapping, now translate what we
939 * now know into VMA flags
940 */
941static unsigned long determine_vm_flags(struct file *file,
942 unsigned long prot,
943 unsigned long flags,
944 unsigned long capabilities)
945{
946 unsigned long vm_flags;
947
948 vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
949 /* vm_flags |= mm->def_flags; */
950
951 if (!(capabilities & NOMMU_MAP_DIRECT)) {
952 /* attempt to share read-only copies of mapped file chunks */
953 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
954 if (file && !(prot & PROT_WRITE))
955 vm_flags |= VM_MAYSHARE;
956 } else {
957 /* overlay a shareable mapping on the backing device or inode
958 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
959 * romfs/cramfs */
960 vm_flags |= VM_MAYSHARE | (capabilities & NOMMU_VMFLAGS);
961 if (flags & MAP_SHARED)
962 vm_flags |= VM_SHARED;
963 }
964
965 /* refuse to let anyone share private mappings with this process if
966 * it's being traced - otherwise breakpoints set in it may interfere
967 * with another untraced process
968 */
969 if ((flags & MAP_PRIVATE) && current->ptrace)
970 vm_flags &= ~VM_MAYSHARE;
971
972 return vm_flags;
973}
974
975/*
976 * set up a shared mapping on a file (the driver or filesystem provides and
977 * pins the storage)
978 */
979static int do_mmap_shared_file(struct vm_area_struct *vma)
980{
981 int ret;
982
983 ret = call_mmap(vma->vm_file, vma);
984 if (ret == 0) {
985 vma->vm_region->vm_top = vma->vm_region->vm_end;
986 return 0;
987 }
988 if (ret != -ENOSYS)
989 return ret;
990
991 /* getting -ENOSYS indicates that direct mmap isn't possible (as
992 * opposed to tried but failed) so we can only give a suitable error as
993 * it's not possible to make a private copy if MAP_SHARED was given */
994 return -ENODEV;
995}
996
997/*
998 * set up a private mapping or an anonymous shared mapping
999 */
1000static int do_mmap_private(struct vm_area_struct *vma,
1001 struct vm_region *region,
1002 unsigned long len,
1003 unsigned long capabilities)
1004{
1005 unsigned long total, point;
1006 void *base;
1007 int ret, order;
1008
1009 /* invoke the file's mapping function so that it can keep track of
1010 * shared mappings on devices or memory
1011 * - VM_MAYSHARE will be set if it may attempt to share
1012 */
1013 if (capabilities & NOMMU_MAP_DIRECT) {
1014 ret = call_mmap(vma->vm_file, vma);
1015 if (ret == 0) {
1016 /* shouldn't return success if we're not sharing */
1017 BUG_ON(!(vma->vm_flags & VM_MAYSHARE));
1018 vma->vm_region->vm_top = vma->vm_region->vm_end;
1019 return 0;
1020 }
1021 if (ret != -ENOSYS)
1022 return ret;
1023
1024 /* getting an ENOSYS error indicates that direct mmap isn't
1025 * possible (as opposed to tried but failed) so we'll try to
1026 * make a private copy of the data and map that instead */
1027 }
1028
1029
1030 /* allocate some memory to hold the mapping
1031 * - note that this may not return a page-aligned address if the object
1032 * we're allocating is smaller than a page
1033 */
1034 order = get_order(len);
1035 total = 1 << order;
1036 point = len >> PAGE_SHIFT;
1037
1038 /* we don't want to allocate a power-of-2 sized page set */
1039 if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages)
1040 total = point;
1041
1042 base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
1043 if (!base)
1044 goto enomem;
1045
1046 atomic_long_add(total, &mmap_pages_allocated);
1047
1048 region->vm_flags = vma->vm_flags |= VM_MAPPED_COPY;
1049 region->vm_start = (unsigned long) base;
1050 region->vm_end = region->vm_start + len;
1051 region->vm_top = region->vm_start + (total << PAGE_SHIFT);
1052
1053 vma->vm_start = region->vm_start;
1054 vma->vm_end = region->vm_start + len;
1055
1056 if (vma->vm_file) {
1057 /* read the contents of a file into the copy */
1058 loff_t fpos;
1059
1060 fpos = vma->vm_pgoff;
1061 fpos <<= PAGE_SHIFT;
1062
1063 ret = kernel_read(vma->vm_file, base, len, &fpos);
1064 if (ret < 0)
1065 goto error_free;
1066
1067 /* clear the last little bit */
1068 if (ret < len)
1069 memset(base + ret, 0, len - ret);
1070
1071 } else {
1072 vma_set_anonymous(vma);
1073 }
1074
1075 return 0;
1076
1077error_free:
1078 free_page_series(region->vm_start, region->vm_top);
1079 region->vm_start = vma->vm_start = 0;
1080 region->vm_end = vma->vm_end = 0;
1081 region->vm_top = 0;
1082 return ret;
1083
1084enomem:
1085 pr_err("Allocation of length %lu from process %d (%s) failed\n",
1086 len, current->pid, current->comm);
1087 show_free_areas(0, NULL);
1088 return -ENOMEM;
1089}
1090
1091/*
1092 * handle mapping creation for uClinux
1093 */
1094unsigned long do_mmap(struct file *file,
1095 unsigned long addr,
1096 unsigned long len,
1097 unsigned long prot,
1098 unsigned long flags,
1099 vm_flags_t vm_flags,
1100 unsigned long pgoff,
1101 unsigned long *populate,
1102 struct list_head *uf)
1103{
1104 struct vm_area_struct *vma;
1105 struct vm_region *region;
1106 struct rb_node *rb;
1107 unsigned long capabilities, result;
1108 int ret;
1109
1110 *populate = 0;
1111
1112 /* decide whether we should attempt the mapping, and if so what sort of
1113 * mapping */
1114 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
1115 &capabilities);
1116 if (ret < 0)
1117 return ret;
1118
1119 /* we ignore the address hint */
1120 addr = 0;
1121 len = PAGE_ALIGN(len);
1122
1123 /* we've determined that we can make the mapping, now translate what we
1124 * now know into VMA flags */
1125 vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
1126
1127 /* we're going to need to record the mapping */
1128 region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
1129 if (!region)
1130 goto error_getting_region;
1131
1132 vma = vm_area_alloc(current->mm);
1133 if (!vma)
1134 goto error_getting_vma;
1135
1136 region->vm_usage = 1;
1137 region->vm_flags = vm_flags;
1138 region->vm_pgoff = pgoff;
1139
1140 vma->vm_flags = vm_flags;
1141 vma->vm_pgoff = pgoff;
1142
1143 if (file) {
1144 region->vm_file = get_file(file);
1145 vma->vm_file = get_file(file);
1146 }
1147
1148 down_write(&nommu_region_sem);
1149
1150 /* if we want to share, we need to check for regions created by other
1151 * mmap() calls that overlap with our proposed mapping
1152 * - we can only share with a superset match on most regular files
1153 * - shared mappings on character devices and memory backed files are
1154 * permitted to overlap inexactly as far as we are concerned for in
1155 * these cases, sharing is handled in the driver or filesystem rather
1156 * than here
1157 */
1158 if (vm_flags & VM_MAYSHARE) {
1159 struct vm_region *pregion;
1160 unsigned long pglen, rpglen, pgend, rpgend, start;
1161
1162 pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
1163 pgend = pgoff + pglen;
1164
1165 for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
1166 pregion = rb_entry(rb, struct vm_region, vm_rb);
1167
1168 if (!(pregion->vm_flags & VM_MAYSHARE))
1169 continue;
1170
1171 /* search for overlapping mappings on the same file */
1172 if (file_inode(pregion->vm_file) !=
1173 file_inode(file))
1174 continue;
1175
1176 if (pregion->vm_pgoff >= pgend)
1177 continue;
1178
1179 rpglen = pregion->vm_end - pregion->vm_start;
1180 rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1181 rpgend = pregion->vm_pgoff + rpglen;
1182 if (pgoff >= rpgend)
1183 continue;
1184
1185 /* handle inexactly overlapping matches between
1186 * mappings */
1187 if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
1188 !(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
1189 /* new mapping is not a subset of the region */
1190 if (!(capabilities & NOMMU_MAP_DIRECT))
1191 goto sharing_violation;
1192 continue;
1193 }
1194
1195 /* we've found a region we can share */
1196 pregion->vm_usage++;
1197 vma->vm_region = pregion;
1198 start = pregion->vm_start;
1199 start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
1200 vma->vm_start = start;
1201 vma->vm_end = start + len;
1202
1203 if (pregion->vm_flags & VM_MAPPED_COPY)
1204 vma->vm_flags |= VM_MAPPED_COPY;
1205 else {
1206 ret = do_mmap_shared_file(vma);
1207 if (ret < 0) {
1208 vma->vm_region = NULL;
1209 vma->vm_start = 0;
1210 vma->vm_end = 0;
1211 pregion->vm_usage--;
1212 pregion = NULL;
1213 goto error_just_free;
1214 }
1215 }
1216 fput(region->vm_file);
1217 kmem_cache_free(vm_region_jar, region);
1218 region = pregion;
1219 result = start;
1220 goto share;
1221 }
1222
1223 /* obtain the address at which to make a shared mapping
1224 * - this is the hook for quasi-memory character devices to
1225 * tell us the location of a shared mapping
1226 */
1227 if (capabilities & NOMMU_MAP_DIRECT) {
1228 addr = file->f_op->get_unmapped_area(file, addr, len,
1229 pgoff, flags);
1230 if (IS_ERR_VALUE(addr)) {
1231 ret = addr;
1232 if (ret != -ENOSYS)
1233 goto error_just_free;
1234
1235 /* the driver refused to tell us where to site
1236 * the mapping so we'll have to attempt to copy
1237 * it */
1238 ret = -ENODEV;
1239 if (!(capabilities & NOMMU_MAP_COPY))
1240 goto error_just_free;
1241
1242 capabilities &= ~NOMMU_MAP_DIRECT;
1243 } else {
1244 vma->vm_start = region->vm_start = addr;
1245 vma->vm_end = region->vm_end = addr + len;
1246 }
1247 }
1248 }
1249
1250 vma->vm_region = region;
1251
1252 /* set up the mapping
1253 * - the region is filled in if NOMMU_MAP_DIRECT is still set
1254 */
1255 if (file && vma->vm_flags & VM_SHARED)
1256 ret = do_mmap_shared_file(vma);
1257 else
1258 ret = do_mmap_private(vma, region, len, capabilities);
1259 if (ret < 0)
1260 goto error_just_free;
1261 add_nommu_region(region);
1262
1263 /* clear anonymous mappings that don't ask for uninitialized data */
1264 if (!vma->vm_file &&
1265 (!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
1266 !(flags & MAP_UNINITIALIZED)))
1267 memset((void *)region->vm_start, 0,
1268 region->vm_end - region->vm_start);
1269
1270 /* okay... we have a mapping; now we have to register it */
1271 result = vma->vm_start;
1272
1273 current->mm->total_vm += len >> PAGE_SHIFT;
1274
1275share:
1276 add_vma_to_mm(current->mm, vma);
1277
1278 /* we flush the region from the icache only when the first executable
1279 * mapping of it is made */
1280 if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
1281 flush_icache_range(region->vm_start, region->vm_end);
1282 region->vm_icache_flushed = true;
1283 }
1284
1285 up_write(&nommu_region_sem);
1286
1287 return result;
1288
1289error_just_free:
1290 up_write(&nommu_region_sem);
1291error:
1292 if (region->vm_file)
1293 fput(region->vm_file);
1294 kmem_cache_free(vm_region_jar, region);
1295 if (vma->vm_file)
1296 fput(vma->vm_file);
1297 vm_area_free(vma);
1298 return ret;
1299
1300sharing_violation:
1301 up_write(&nommu_region_sem);
1302 pr_warn("Attempt to share mismatched mappings\n");
1303 ret = -EINVAL;
1304 goto error;
1305
1306error_getting_vma:
1307 kmem_cache_free(vm_region_jar, region);
1308 pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
1309 len, current->pid);
1310 show_free_areas(0, NULL);
1311 return -ENOMEM;
1312
1313error_getting_region:
1314 pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
1315 len, current->pid);
1316 show_free_areas(0, NULL);
1317 return -ENOMEM;
1318}
1319
1320unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
1321 unsigned long prot, unsigned long flags,
1322 unsigned long fd, unsigned long pgoff)
1323{
1324 struct file *file = NULL;
1325 unsigned long retval = -EBADF;
1326
1327 audit_mmap_fd(fd, flags);
1328 if (!(flags & MAP_ANONYMOUS)) {
1329 file = fget(fd);
1330 if (!file)
1331 goto out;
1332 }
1333
1334 flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
1335
1336 retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
1337
1338 if (file)
1339 fput(file);
1340out:
1341 return retval;
1342}
1343
1344SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
1345 unsigned long, prot, unsigned long, flags,
1346 unsigned long, fd, unsigned long, pgoff)
1347{
1348 return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
1349}
1350
1351#ifdef __ARCH_WANT_SYS_OLD_MMAP
1352struct mmap_arg_struct {
1353 unsigned long addr;
1354 unsigned long len;
1355 unsigned long prot;
1356 unsigned long flags;
1357 unsigned long fd;
1358 unsigned long offset;
1359};
1360
1361SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
1362{
1363 struct mmap_arg_struct a;
1364
1365 if (copy_from_user(&a, arg, sizeof(a)))
1366 return -EFAULT;
1367 if (offset_in_page(a.offset))
1368 return -EINVAL;
1369
1370 return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
1371 a.offset >> PAGE_SHIFT);
1372}
1373#endif /* __ARCH_WANT_SYS_OLD_MMAP */
1374
1375/*
1376 * split a vma into two pieces at address 'addr', a new vma is allocated either
1377 * for the first part or the tail.
1378 */
1379int split_vma(struct mm_struct *mm, struct vm_area_struct *vma,
1380 unsigned long addr, int new_below)
1381{
1382 struct vm_area_struct *new;
1383 struct vm_region *region;
1384 unsigned long npages;
1385
1386 /* we're only permitted to split anonymous regions (these should have
1387 * only a single usage on the region) */
1388 if (vma->vm_file)
1389 return -ENOMEM;
1390
1391 if (mm->map_count >= sysctl_max_map_count)
1392 return -ENOMEM;
1393
1394 region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
1395 if (!region)
1396 return -ENOMEM;
1397
1398 new = vm_area_dup(vma);
1399 if (!new) {
1400 kmem_cache_free(vm_region_jar, region);
1401 return -ENOMEM;
1402 }
1403
1404 /* most fields are the same, copy all, and then fixup */
1405 *region = *vma->vm_region;
1406 new->vm_region = region;
1407
1408 npages = (addr - vma->vm_start) >> PAGE_SHIFT;
1409
1410 if (new_below) {
1411 region->vm_top = region->vm_end = new->vm_end = addr;
1412 } else {
1413 region->vm_start = new->vm_start = addr;
1414 region->vm_pgoff = new->vm_pgoff += npages;
1415 }
1416
1417 if (new->vm_ops && new->vm_ops->open)
1418 new->vm_ops->open(new);
1419
1420 delete_vma_from_mm(vma);
1421 down_write(&nommu_region_sem);
1422 delete_nommu_region(vma->vm_region);
1423 if (new_below) {
1424 vma->vm_region->vm_start = vma->vm_start = addr;
1425 vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
1426 } else {
1427 vma->vm_region->vm_end = vma->vm_end = addr;
1428 vma->vm_region->vm_top = addr;
1429 }
1430 add_nommu_region(vma->vm_region);
1431 add_nommu_region(new->vm_region);
1432 up_write(&nommu_region_sem);
1433 add_vma_to_mm(mm, vma);
1434 add_vma_to_mm(mm, new);
1435 return 0;
1436}
1437
1438/*
1439 * shrink a VMA by removing the specified chunk from either the beginning or
1440 * the end
1441 */
1442static int shrink_vma(struct mm_struct *mm,
1443 struct vm_area_struct *vma,
1444 unsigned long from, unsigned long to)
1445{
1446 struct vm_region *region;
1447
1448 /* adjust the VMA's pointers, which may reposition it in the MM's tree
1449 * and list */
1450 delete_vma_from_mm(vma);
1451 if (from > vma->vm_start)
1452 vma->vm_end = from;
1453 else
1454 vma->vm_start = to;
1455 add_vma_to_mm(mm, vma);
1456
1457 /* cut the backing region down to size */
1458 region = vma->vm_region;
1459 BUG_ON(region->vm_usage != 1);
1460
1461 down_write(&nommu_region_sem);
1462 delete_nommu_region(region);
1463 if (from > region->vm_start) {
1464 to = region->vm_top;
1465 region->vm_top = region->vm_end = from;
1466 } else {
1467 region->vm_start = to;
1468 }
1469 add_nommu_region(region);
1470 up_write(&nommu_region_sem);
1471
1472 free_page_series(from, to);
1473 return 0;
1474}
1475
1476/*
1477 * release a mapping
1478 * - under NOMMU conditions the chunk to be unmapped must be backed by a single
1479 * VMA, though it need not cover the whole VMA
1480 */
1481int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
1482{
1483 struct vm_area_struct *vma;
1484 unsigned long end;
1485 int ret;
1486
1487 len = PAGE_ALIGN(len);
1488 if (len == 0)
1489 return -EINVAL;
1490
1491 end = start + len;
1492
1493 /* find the first potentially overlapping VMA */
1494 vma = find_vma(mm, start);
1495 if (!vma) {
1496 static int limit;
1497 if (limit < 5) {
1498 pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
1499 current->pid, current->comm,
1500 start, start + len - 1);
1501 limit++;
1502 }
1503 return -EINVAL;
1504 }
1505
1506 /* we're allowed to split an anonymous VMA but not a file-backed one */
1507 if (vma->vm_file) {
1508 do {
1509 if (start > vma->vm_start)
1510 return -EINVAL;
1511 if (end == vma->vm_end)
1512 goto erase_whole_vma;
1513 vma = vma->vm_next;
1514 } while (vma);
1515 return -EINVAL;
1516 } else {
1517 /* the chunk must be a subset of the VMA found */
1518 if (start == vma->vm_start && end == vma->vm_end)
1519 goto erase_whole_vma;
1520 if (start < vma->vm_start || end > vma->vm_end)
1521 return -EINVAL;
1522 if (offset_in_page(start))
1523 return -EINVAL;
1524 if (end != vma->vm_end && offset_in_page(end))
1525 return -EINVAL;
1526 if (start != vma->vm_start && end != vma->vm_end) {
1527 ret = split_vma(mm, vma, start, 1);
1528 if (ret < 0)
1529 return ret;
1530 }
1531 return shrink_vma(mm, vma, start, end);
1532 }
1533
1534erase_whole_vma:
1535 delete_vma_from_mm(vma);
1536 delete_vma(mm, vma);
1537 return 0;
1538}
1539EXPORT_SYMBOL(do_munmap);
1540
1541int vm_munmap(unsigned long addr, size_t len)
1542{
1543 struct mm_struct *mm = current->mm;
1544 int ret;
1545
1546 down_write(&mm->mmap_sem);
1547 ret = do_munmap(mm, addr, len, NULL);
1548 up_write(&mm->mmap_sem);
1549 return ret;
1550}
1551EXPORT_SYMBOL(vm_munmap);
1552
1553SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
1554{
1555 return vm_munmap(addr, len);
1556}
1557
1558/*
1559 * release all the mappings made in a process's VM space
1560 */
1561void exit_mmap(struct mm_struct *mm)
1562{
1563 struct vm_area_struct *vma;
1564
1565 if (!mm)
1566 return;
1567
1568 mm->total_vm = 0;
1569
1570 while ((vma = mm->mmap)) {
1571 mm->mmap = vma->vm_next;
1572 delete_vma_from_mm(vma);
1573 delete_vma(mm, vma);
1574 cond_resched();
1575 }
1576}
1577
1578int vm_brk(unsigned long addr, unsigned long len)
1579{
1580 return -ENOMEM;
1581}
1582
1583/*
1584 * expand (or shrink) an existing mapping, potentially moving it at the same
1585 * time (controlled by the MREMAP_MAYMOVE flag and available VM space)
1586 *
1587 * under NOMMU conditions, we only permit changing a mapping's size, and only
1588 * as long as it stays within the region allocated by do_mmap_private() and the
1589 * block is not shareable
1590 *
1591 * MREMAP_FIXED is not supported under NOMMU conditions
1592 */
1593static unsigned long do_mremap(unsigned long addr,
1594 unsigned long old_len, unsigned long new_len,
1595 unsigned long flags, unsigned long new_addr)
1596{
1597 struct vm_area_struct *vma;
1598
1599 /* insanity checks first */
1600 old_len = PAGE_ALIGN(old_len);
1601 new_len = PAGE_ALIGN(new_len);
1602 if (old_len == 0 || new_len == 0)
1603 return (unsigned long) -EINVAL;
1604
1605 if (offset_in_page(addr))
1606 return -EINVAL;
1607
1608 if (flags & MREMAP_FIXED && new_addr != addr)
1609 return (unsigned long) -EINVAL;
1610
1611 vma = find_vma_exact(current->mm, addr, old_len);
1612 if (!vma)
1613 return (unsigned long) -EINVAL;
1614
1615 if (vma->vm_end != vma->vm_start + old_len)
1616 return (unsigned long) -EFAULT;
1617
1618 if (vma->vm_flags & VM_MAYSHARE)
1619 return (unsigned long) -EPERM;
1620
1621 if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
1622 return (unsigned long) -ENOMEM;
1623
1624 /* all checks complete - do it */
1625 vma->vm_end = vma->vm_start + new_len;
1626 return vma->vm_start;
1627}
1628
1629SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
1630 unsigned long, new_len, unsigned long, flags,
1631 unsigned long, new_addr)
1632{
1633 unsigned long ret;
1634
1635 down_write(¤t->mm->mmap_sem);
1636 ret = do_mremap(addr, old_len, new_len, flags, new_addr);
1637 up_write(¤t->mm->mmap_sem);
1638 return ret;
1639}
1640
1641struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1642 unsigned int foll_flags)
1643{
1644 return NULL;
1645}
1646
1647int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1648 unsigned long pfn, unsigned long size, pgprot_t prot)
1649{
1650 if (addr != (pfn << PAGE_SHIFT))
1651 return -EINVAL;
1652
1653 vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1654 return 0;
1655}
1656EXPORT_SYMBOL(remap_pfn_range);
1657
1658int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
1659{
1660 unsigned long pfn = start >> PAGE_SHIFT;
1661 unsigned long vm_len = vma->vm_end - vma->vm_start;
1662
1663 pfn += vma->vm_pgoff;
1664 return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
1665}
1666EXPORT_SYMBOL(vm_iomap_memory);
1667
1668int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
1669 unsigned long pgoff)
1670{
1671 unsigned int size = vma->vm_end - vma->vm_start;
1672
1673 if (!(vma->vm_flags & VM_USERMAP))
1674 return -EINVAL;
1675
1676 vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
1677 vma->vm_end = vma->vm_start + size;
1678
1679 return 0;
1680}
1681EXPORT_SYMBOL(remap_vmalloc_range);
1682
1683unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1684 unsigned long len, unsigned long pgoff, unsigned long flags)
1685{
1686 return -ENOMEM;
1687}
1688
1689vm_fault_t filemap_fault(struct vm_fault *vmf)
1690{
1691 BUG();
1692 return 0;
1693}
1694EXPORT_SYMBOL(filemap_fault);
1695
1696void filemap_map_pages(struct vm_fault *vmf,
1697 pgoff_t start_pgoff, pgoff_t end_pgoff)
1698{
1699 BUG();
1700}
1701EXPORT_SYMBOL(filemap_map_pages);
1702
1703int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
1704 unsigned long addr, void *buf, int len, unsigned int gup_flags)
1705{
1706 struct vm_area_struct *vma;
1707 int write = gup_flags & FOLL_WRITE;
1708
1709 if (down_read_killable(&mm->mmap_sem))
1710 return 0;
1711
1712 /* the access must start within one of the target process's mappings */
1713 vma = find_vma(mm, addr);
1714 if (vma) {
1715 /* don't overrun this mapping */
1716 if (addr + len >= vma->vm_end)
1717 len = vma->vm_end - addr;
1718
1719 /* only read or write mappings where it is permitted */
1720 if (write && vma->vm_flags & VM_MAYWRITE)
1721 copy_to_user_page(vma, NULL, addr,
1722 (void *) addr, buf, len);
1723 else if (!write && vma->vm_flags & VM_MAYREAD)
1724 copy_from_user_page(vma, NULL, addr,
1725 buf, (void *) addr, len);
1726 else
1727 len = 0;
1728 } else {
1729 len = 0;
1730 }
1731
1732 up_read(&mm->mmap_sem);
1733
1734 return len;
1735}
1736
1737/**
1738 * access_remote_vm - access another process' address space
1739 * @mm: the mm_struct of the target address space
1740 * @addr: start address to access
1741 * @buf: source or destination buffer
1742 * @len: number of bytes to transfer
1743 * @gup_flags: flags modifying lookup behaviour
1744 *
1745 * The caller must hold a reference on @mm.
1746 */
1747int access_remote_vm(struct mm_struct *mm, unsigned long addr,
1748 void *buf, int len, unsigned int gup_flags)
1749{
1750 return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags);
1751}
1752
1753/*
1754 * Access another process' address space.
1755 * - source/target buffer must be kernel space
1756 */
1757int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
1758 unsigned int gup_flags)
1759{
1760 struct mm_struct *mm;
1761
1762 if (addr + len < addr)
1763 return 0;
1764
1765 mm = get_task_mm(tsk);
1766 if (!mm)
1767 return 0;
1768
1769 len = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
1770
1771 mmput(mm);
1772 return len;
1773}
1774EXPORT_SYMBOL_GPL(access_process_vm);
1775
1776/**
1777 * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
1778 * @inode: The inode to check
1779 * @size: The current filesize of the inode
1780 * @newsize: The proposed filesize of the inode
1781 *
1782 * Check the shared mappings on an inode on behalf of a shrinking truncate to
1783 * make sure that that any outstanding VMAs aren't broken and then shrink the
1784 * vm_regions that extend that beyond so that do_mmap_pgoff() doesn't
1785 * automatically grant mappings that are too large.
1786 */
1787int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
1788 size_t newsize)
1789{
1790 struct vm_area_struct *vma;
1791 struct vm_region *region;
1792 pgoff_t low, high;
1793 size_t r_size, r_top;
1794
1795 low = newsize >> PAGE_SHIFT;
1796 high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
1797
1798 down_write(&nommu_region_sem);
1799 i_mmap_lock_read(inode->i_mapping);
1800
1801 /* search for VMAs that fall within the dead zone */
1802 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
1803 /* found one - only interested if it's shared out of the page
1804 * cache */
1805 if (vma->vm_flags & VM_SHARED) {
1806 i_mmap_unlock_read(inode->i_mapping);
1807 up_write(&nommu_region_sem);
1808 return -ETXTBSY; /* not quite true, but near enough */
1809 }
1810 }
1811
1812 /* reduce any regions that overlap the dead zone - if in existence,
1813 * these will be pointed to by VMAs that don't overlap the dead zone
1814 *
1815 * we don't check for any regions that start beyond the EOF as there
1816 * shouldn't be any
1817 */
1818 vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
1819 if (!(vma->vm_flags & VM_SHARED))
1820 continue;
1821
1822 region = vma->vm_region;
1823 r_size = region->vm_top - region->vm_start;
1824 r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
1825
1826 if (r_top > newsize) {
1827 region->vm_top -= r_top - newsize;
1828 if (region->vm_end > region->vm_top)
1829 region->vm_end = region->vm_top;
1830 }
1831 }
1832
1833 i_mmap_unlock_read(inode->i_mapping);
1834 up_write(&nommu_region_sem);
1835 return 0;
1836}
1837
1838/*
1839 * Initialise sysctl_user_reserve_kbytes.
1840 *
1841 * This is intended to prevent a user from starting a single memory hogging
1842 * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
1843 * mode.
1844 *
1845 * The default value is min(3% of free memory, 128MB)
1846 * 128MB is enough to recover with sshd/login, bash, and top/kill.
1847 */
1848static int __meminit init_user_reserve(void)
1849{
1850 unsigned long free_kbytes;
1851
1852 free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
1853
1854 sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
1855 return 0;
1856}
1857subsys_initcall(init_user_reserve);
1858
1859/*
1860 * Initialise sysctl_admin_reserve_kbytes.
1861 *
1862 * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
1863 * to log in and kill a memory hogging process.
1864 *
1865 * Systems with more than 256MB will reserve 8MB, enough to recover
1866 * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
1867 * only reserve 3% of free pages by default.
1868 */
1869static int __meminit init_admin_reserve(void)
1870{
1871 unsigned long free_kbytes;
1872
1873 free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10);
1874
1875 sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
1876 return 0;
1877}
1878subsys_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)