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).
7 * See Documentation/nommu-mmap.txt
9 * Copyright (c) 2004-2005 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>
16 #include <linux/mman.h>
17 #include <linux/swap.h>
18 #include <linux/file.h>
19 #include <linux/highmem.h>
20 #include <linux/pagemap.h>
21 #include <linux/slab.h>
22 #include <linux/vmalloc.h>
23 #include <linux/ptrace.h>
24 #include <linux/blkdev.h>
25 #include <linux/backing-dev.h>
26 #include <linux/mount.h>
27 #include <linux/personality.h>
28 #include <linux/security.h>
29 #include <linux/syscalls.h>
30 #include <linux/vs_base.h>
31 #include <linux/vs_memory.h>
33 #include <asm/uaccess.h>
35 #include <asm/tlbflush.h>
39 unsigned long max_mapnr;
40 unsigned long num_physpages;
41 unsigned long askedalloc, realalloc;
42 atomic_t vm_committed_space = ATOMIC_INIT(0);
43 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
44 int sysctl_overcommit_ratio = 50; /* default is 50% */
45 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
46 int heap_stack_gap = 0;
48 EXPORT_SYMBOL(mem_map);
49 EXPORT_SYMBOL(__vm_enough_memory);
51 /* list of shareable VMAs */
52 struct rb_root nommu_vma_tree = RB_ROOT;
53 DECLARE_RWSEM(nommu_vma_sem);
55 struct vm_operations_struct generic_file_vm_ops = {
59 EXPORT_SYMBOL(vmalloc_to_page);
60 EXPORT_SYMBOL(vmalloc_32);
62 EXPORT_SYMBOL(vunmap);
65 * Handle all mappings that got truncated by a "truncate()"
68 * NOTE! We have to be ready to update the memory sharing
69 * between the file and the memory map for a potential last
70 * incomplete page. Ugly, but necessary.
72 int vmtruncate(struct inode *inode, loff_t offset)
74 struct address_space *mapping = inode->i_mapping;
77 if (inode->i_size < offset)
79 i_size_write(inode, offset);
81 truncate_inode_pages(mapping, offset);
85 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
86 if (limit != RLIM_INFINITY && offset > limit)
88 if (offset > inode->i_sb->s_maxbytes)
90 i_size_write(inode, offset);
93 if (inode->i_op && inode->i_op->truncate)
94 inode->i_op->truncate(inode);
97 send_sig(SIGXFSZ, current, 0);
102 EXPORT_SYMBOL(vmtruncate);
105 * Return the total memory allocated for this pointer, not
106 * just what the caller asked for.
108 * Doesn't have to be accurate, i.e. may have races.
110 unsigned int kobjsize(const void *objp)
114 if (!objp || !((page = virt_to_page(objp))))
120 BUG_ON(page->index < 0);
121 BUG_ON(page->index >= MAX_ORDER);
123 return (PAGE_SIZE << page->index);
127 * The nommu dodgy version :-)
129 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
130 unsigned long start, int len, int write, int force,
131 struct page **pages, struct vm_area_struct **vmas)
134 static struct vm_area_struct dummy_vma;
136 for (i = 0; i < len; i++) {
138 pages[i] = virt_to_page(start);
140 page_cache_get(pages[i]);
143 vmas[i] = &dummy_vma;
149 EXPORT_SYMBOL(get_user_pages);
151 DEFINE_RWLOCK(vmlist_lock);
152 struct vm_struct *vmlist;
154 void vfree(void *addr)
159 void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
162 * kmalloc doesn't like __GFP_HIGHMEM for some reason
164 return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
167 struct page * vmalloc_to_page(void *addr)
169 return virt_to_page(addr);
172 unsigned long vmalloc_to_pfn(void *addr)
174 return page_to_pfn(virt_to_page(addr));
178 long vread(char *buf, char *addr, unsigned long count)
180 memcpy(buf, addr, count);
184 long vwrite(char *buf, char *addr, unsigned long count)
186 /* Don't allow overflow */
187 if ((unsigned long) addr + count < count)
188 count = -(unsigned long) addr;
190 memcpy(addr, buf, count);
195 * vmalloc - allocate virtually continguos memory
197 * @size: allocation size
199 * Allocate enough pages to cover @size from the page level
200 * allocator and map them into continguos kernel virtual space.
202 * For tight cotrol over page level allocator and protection flags
203 * use __vmalloc() instead.
205 void *vmalloc(unsigned long size)
207 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
209 EXPORT_SYMBOL(vmalloc);
211 void *vmalloc_node(unsigned long size, int node)
213 return vmalloc(size);
215 EXPORT_SYMBOL(vmalloc_node);
218 * vmalloc_32 - allocate virtually continguos memory (32bit addressable)
220 * @size: allocation size
222 * Allocate enough 32bit PA addressable pages to cover @size from the
223 * page level allocator and map them into continguos kernel virtual space.
225 void *vmalloc_32(unsigned long size)
227 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
230 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
236 void vunmap(void *addr)
242 * sys_brk() for the most part doesn't need the global kernel
243 * lock, except when an application is doing something nasty
244 * like trying to un-brk an area that has already been mapped
245 * to a regular file. in this case, the unmapping will need
246 * to invoke file system routines that need the global lock.
248 asmlinkage unsigned long sys_brk(unsigned long brk)
250 struct mm_struct *mm = current->mm;
252 if (brk < mm->start_brk || brk > mm->context.end_brk)
259 * Always allow shrinking brk
261 if (brk <= mm->brk) {
267 * Ok, looks good - let it rip.
269 return mm->brk = brk;
273 static void show_process_blocks(void)
275 struct vm_list_struct *vml;
277 printk("Process blocks %d:", current->pid);
279 for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) {
280 printk(" %p: %p", vml, vml->vma);
282 printk(" (%d @%lx #%d)",
283 kobjsize((void *) vml->vma->vm_start),
285 atomic_read(&vml->vma->vm_usage));
286 printk(vml->next ? " ->" : ".\n");
291 static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
293 struct vm_area_struct *vma;
294 struct rb_node *n = nommu_vma_tree.rb_node;
297 vma = rb_entry(n, struct vm_area_struct, vm_rb);
299 if (start < vma->vm_start)
301 else if (start > vma->vm_start)
310 static void add_nommu_vma(struct vm_area_struct *vma)
312 struct vm_area_struct *pvma;
313 struct address_space *mapping;
314 struct rb_node **p = &nommu_vma_tree.rb_node;
315 struct rb_node *parent = NULL;
317 /* add the VMA to the mapping */
319 mapping = vma->vm_file->f_mapping;
321 flush_dcache_mmap_lock(mapping);
322 vma_prio_tree_insert(vma, &mapping->i_mmap);
323 flush_dcache_mmap_unlock(mapping);
326 /* add the VMA to the master list */
329 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
331 if (vma->vm_start < pvma->vm_start) {
334 else if (vma->vm_start > pvma->vm_start) {
338 /* mappings are at the same address - this can only
339 * happen for shared-mem chardevs and shared file
340 * mappings backed by ramfs/tmpfs */
341 BUG_ON(!(pvma->vm_flags & VM_SHARED));
352 rb_link_node(&vma->vm_rb, parent, p);
353 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
356 static void delete_nommu_vma(struct vm_area_struct *vma)
358 struct address_space *mapping;
360 /* remove the VMA from the mapping */
362 mapping = vma->vm_file->f_mapping;
364 flush_dcache_mmap_lock(mapping);
365 vma_prio_tree_remove(vma, &mapping->i_mmap);
366 flush_dcache_mmap_unlock(mapping);
369 /* remove from the master list */
370 rb_erase(&vma->vm_rb, &nommu_vma_tree);
374 * determine whether a mapping should be permitted and, if so, what sort of
375 * mapping we're capable of supporting
377 static int validate_mmap_request(struct file *file,
383 unsigned long *_capabilities)
385 unsigned long capabilities;
386 unsigned long reqprot = prot;
389 /* do the simple checks first */
390 if (flags & MAP_FIXED || addr) {
392 "%d: Can't do fixed-address/overlay mmap of RAM\n",
397 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
398 (flags & MAP_TYPE) != MAP_SHARED)
401 if (PAGE_ALIGN(len) == 0)
407 /* offset overflow? */
408 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
412 /* validate file mapping requests */
413 struct address_space *mapping;
415 /* files must support mmap */
416 if (!file->f_op || !file->f_op->mmap)
419 /* work out if what we've got could possibly be shared
420 * - we support chardevs that provide their own "memory"
421 * - we support files/blockdevs that are memory backed
423 mapping = file->f_mapping;
425 mapping = file->f_dentry->d_inode->i_mapping;
428 if (mapping && mapping->backing_dev_info)
429 capabilities = mapping->backing_dev_info->capabilities;
432 /* no explicit capabilities set, so assume some
434 switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
437 capabilities = BDI_CAP_MAP_COPY;
452 /* eliminate any capabilities that we can't support on this
454 if (!file->f_op->get_unmapped_area)
455 capabilities &= ~BDI_CAP_MAP_DIRECT;
456 if (!file->f_op->read)
457 capabilities &= ~BDI_CAP_MAP_COPY;
459 if (flags & MAP_SHARED) {
460 /* do checks for writing, appending and locking */
461 if ((prot & PROT_WRITE) &&
462 !(file->f_mode & FMODE_WRITE))
465 if (IS_APPEND(file->f_dentry->d_inode) &&
466 (file->f_mode & FMODE_WRITE))
469 if (locks_verify_locked(file->f_dentry->d_inode))
472 if (!(capabilities & BDI_CAP_MAP_DIRECT))
475 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
476 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
477 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
479 printk("MAP_SHARED not completely supported on !MMU\n");
483 /* we mustn't privatise shared mappings */
484 capabilities &= ~BDI_CAP_MAP_COPY;
487 /* we're going to read the file into private memory we
489 if (!(capabilities & BDI_CAP_MAP_COPY))
492 /* we don't permit a private writable mapping to be
493 * shared with the backing device */
494 if (prot & PROT_WRITE)
495 capabilities &= ~BDI_CAP_MAP_DIRECT;
498 /* handle executable mappings and implied executable
500 if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) {
501 if (prot & PROT_EXEC)
504 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
505 /* handle implication of PROT_EXEC by PROT_READ */
506 if (current->personality & READ_IMPLIES_EXEC) {
507 if (capabilities & BDI_CAP_EXEC_MAP)
511 else if ((prot & PROT_READ) &&
512 (prot & PROT_EXEC) &&
513 !(capabilities & BDI_CAP_EXEC_MAP)
515 /* backing file is not executable, try to copy */
516 capabilities &= ~BDI_CAP_MAP_DIRECT;
520 /* anonymous mappings are always memory backed and can be
523 capabilities = BDI_CAP_MAP_COPY;
525 /* handle PROT_EXEC implication by PROT_READ */
526 if ((prot & PROT_READ) &&
527 (current->personality & READ_IMPLIES_EXEC))
531 /* allow the security API to have its say */
532 ret = security_file_mmap(file, reqprot, prot, flags);
537 *_capabilities = capabilities;
542 * we've determined that we can make the mapping, now translate what we
543 * now know into VMA flags
545 static unsigned long determine_vm_flags(struct file *file,
548 unsigned long capabilities)
550 unsigned long vm_flags;
552 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
553 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
554 /* vm_flags |= mm->def_flags; */
556 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
557 /* attempt to share read-only copies of mapped file chunks */
558 if (file && !(prot & PROT_WRITE))
559 vm_flags |= VM_MAYSHARE;
562 /* overlay a shareable mapping on the backing device or inode
563 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
565 if (flags & MAP_SHARED)
566 vm_flags |= VM_MAYSHARE | VM_SHARED;
567 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
568 vm_flags |= VM_MAYSHARE;
571 /* refuse to let anyone share private mappings with this process if
572 * it's being traced - otherwise breakpoints set in it may interfere
573 * with another untraced process
575 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
576 vm_flags &= ~VM_MAYSHARE;
582 * set up a shared mapping on a file
584 static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
588 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
592 /* getting an ENOSYS error indicates that direct mmap isn't
593 * possible (as opposed to tried but failed) so we'll fall
594 * through to making a private copy of the data and mapping
600 * set up a private mapping or an anonymous shared mapping
602 static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
607 /* invoke the file's mapping function so that it can keep track of
608 * shared mappings on devices or memory
609 * - VM_MAYSHARE will be set if it may attempt to share
612 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
613 if (ret != -ENOSYS) {
614 /* shouldn't return success if we're not sharing */
615 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
616 return ret; /* success or a real error */
619 /* getting an ENOSYS error indicates that direct mmap isn't
620 * possible (as opposed to tried but failed) so we'll try to
621 * make a private copy of the data and map that instead */
624 /* allocate some memory to hold the mapping
625 * - note that this may not return a page-aligned address if the object
626 * we're allocating is smaller than a page
628 base = kmalloc(len, GFP_KERNEL|__GFP_COMP);
632 vma->vm_start = (unsigned long) base;
633 vma->vm_end = vma->vm_start + len;
634 vma->vm_flags |= VM_MAPPED_COPY;
637 if (len + WARN_ON_SLACK <= kobjsize(result))
638 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
639 len, current->pid, kobjsize(result) - len);
643 /* read the contents of a file into the copy */
647 fpos = vma->vm_pgoff;
652 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
658 /* clear the last little bit */
660 memset(base + ret, 0, len - ret);
663 /* if it's an anonymous mapping, then just clear it */
664 memset(base, 0, len);
675 printk("Allocation of length %lu from process %d failed\n",
682 * handle mapping creation for uClinux
684 unsigned long do_mmap_pgoff(struct file *file,
691 struct vm_list_struct *vml = NULL;
692 struct vm_area_struct *vma = NULL;
694 unsigned long capabilities, vm_flags;
698 /* decide whether we should attempt the mapping, and if so what sort of
700 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
705 /* we've determined that we can make the mapping, now translate what we
706 * now know into VMA flags */
707 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
709 /* we're going to need to record the mapping if it works */
710 vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
712 goto error_getting_vml;
713 memset(vml, 0, sizeof(*vml));
715 down_write(&nommu_vma_sem);
717 /* if we want to share, we need to check for VMAs created by other
718 * mmap() calls that overlap with our proposed mapping
719 * - we can only share with an exact match on most regular files
720 * - shared mappings on character devices and memory backed files are
721 * permitted to overlap inexactly as far as we are concerned for in
722 * these cases, sharing is handled in the driver or filesystem rather
725 if (vm_flags & VM_MAYSHARE) {
726 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
727 unsigned long vmpglen;
729 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
730 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
732 if (!(vma->vm_flags & VM_MAYSHARE))
735 /* search for overlapping mappings on the same file */
736 if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
739 if (vma->vm_pgoff >= pgoff + pglen)
742 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
743 vmpglen >>= PAGE_SHIFT;
744 if (pgoff >= vma->vm_pgoff + vmpglen)
747 /* handle inexactly overlapping matches between mappings */
748 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
749 if (!(capabilities & BDI_CAP_MAP_DIRECT))
750 goto sharing_violation;
754 /* we've found a VMA we can share */
755 atomic_inc(&vma->vm_usage);
758 result = (void *) vma->vm_start;
764 /* obtain the address at which to make a shared mapping
765 * - this is the hook for quasi-memory character devices to
766 * tell us the location of a shared mapping
768 if (file && file->f_op->get_unmapped_area) {
769 addr = file->f_op->get_unmapped_area(file, addr, len,
771 if (IS_ERR((void *) addr)) {
773 if (ret != (unsigned long) -ENOSYS)
776 /* the driver refused to tell us where to site
777 * the mapping so we'll have to attempt to copy
779 ret = (unsigned long) -ENODEV;
780 if (!(capabilities & BDI_CAP_MAP_COPY))
783 capabilities &= ~BDI_CAP_MAP_DIRECT;
788 /* we're going to need a VMA struct as well */
789 vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
791 goto error_getting_vma;
793 memset(vma, 0, sizeof(*vma));
794 INIT_LIST_HEAD(&vma->anon_vma_node);
795 atomic_set(&vma->vm_usage, 1);
799 vma->vm_flags = vm_flags;
800 vma->vm_start = addr;
801 vma->vm_end = addr + len;
802 vma->vm_pgoff = pgoff;
806 /* set up the mapping */
807 if (file && vma->vm_flags & VM_SHARED)
808 ret = do_mmap_shared_file(vma, len);
810 ret = do_mmap_private(vma, len);
814 /* okay... we have a mapping; now we have to register it */
815 result = (void *) vma->vm_start;
817 if (vma->vm_flags & VM_MAPPED_COPY) {
818 realalloc += kobjsize(result);
822 realalloc += kobjsize(vma);
823 askedalloc += sizeof(*vma);
825 vx_vmpages_add(current->mm, len >> PAGE_SHIFT);
830 realalloc += kobjsize(vml);
831 askedalloc += sizeof(*vml);
833 vml->next = current->mm->context.vmlist;
834 current->mm->context.vmlist = vml;
836 up_write(&nommu_vma_sem);
838 if (prot & PROT_EXEC)
839 flush_icache_range((unsigned long) result,
840 (unsigned long) result + len);
843 printk("do_mmap:\n");
844 show_process_blocks();
847 return (unsigned long) result;
850 up_write(&nommu_vma_sem);
859 up_write(&nommu_vma_sem);
860 printk("Attempt to share mismatched mappings\n");
865 up_write(&nommu_vma_sem);
867 printk("Allocation of vma for %lu byte allocation from process %d failed\n",
873 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
880 * handle mapping disposal for uClinux
882 static void put_vma(struct vm_area_struct *vma)
885 down_write(&nommu_vma_sem);
887 if (atomic_dec_and_test(&vma->vm_usage)) {
888 delete_nommu_vma(vma);
890 if (vma->vm_ops && vma->vm_ops->close)
891 vma->vm_ops->close(vma);
893 /* IO memory and memory shared directly out of the pagecache from
894 * ramfs/tmpfs mustn't be released here */
895 if (vma->vm_flags & VM_MAPPED_COPY) {
896 realalloc -= kobjsize((void *) vma->vm_start);
897 askedalloc -= vma->vm_end - vma->vm_start;
898 kfree((void *) vma->vm_start);
901 realalloc -= kobjsize(vma);
902 askedalloc -= sizeof(*vma);
909 up_write(&nommu_vma_sem);
913 int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
915 struct vm_list_struct *vml, **parent;
916 unsigned long end = addr + len;
919 printk("do_munmap:\n");
922 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
923 if ((*parent)->vma->vm_start == addr &&
924 ((len == 0) || ((*parent)->vma->vm_end == end)))
927 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
928 current->pid, current->comm, (void *) addr);
937 realalloc -= kobjsize(vml);
938 askedalloc -= sizeof(*vml);
941 update_hiwater_vm(mm);
942 vx_vmpages_sub(mm, len >> PAGE_SHIFT);
945 show_process_blocks();
951 /* Release all mmaps. */
952 void exit_mmap(struct mm_struct * mm)
954 struct vm_list_struct *tmp;
958 printk("Exit_mmap:\n");
961 vx_vmpages_sub(mm, mm->total_vm);
963 while ((tmp = mm->context.vmlist)) {
964 mm->context.vmlist = tmp->next;
967 realalloc -= kobjsize(tmp);
968 askedalloc -= sizeof(*tmp);
973 show_process_blocks();
978 asmlinkage long sys_munmap(unsigned long addr, size_t len)
981 struct mm_struct *mm = current->mm;
983 down_write(&mm->mmap_sem);
984 ret = do_munmap(mm, addr, len);
985 up_write(&mm->mmap_sem);
989 unsigned long do_brk(unsigned long addr, unsigned long len)
995 * Expand (or shrink) an existing mapping, potentially moving it at the
996 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
998 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
999 * This option implies MREMAP_MAYMOVE.
1001 * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
1002 * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
1004 unsigned long do_mremap(unsigned long addr,
1005 unsigned long old_len, unsigned long new_len,
1006 unsigned long flags, unsigned long new_addr)
1008 struct vm_list_struct *vml = NULL;
1010 /* insanity checks first */
1012 return (unsigned long) -EINVAL;
1014 if (flags & MREMAP_FIXED && new_addr != addr)
1015 return (unsigned long) -EINVAL;
1017 for (vml = current->mm->context.vmlist; vml; vml = vml->next)
1018 if (vml->vma->vm_start == addr)
1021 return (unsigned long) -EINVAL;
1024 if (vml->vma->vm_end != vml->vma->vm_start + old_len)
1025 return (unsigned long) -EFAULT;
1027 if (vml->vma->vm_flags & VM_MAYSHARE)
1028 return (unsigned long) -EPERM;
1030 if (new_len > kobjsize((void *) addr))
1031 return (unsigned long) -ENOMEM;
1033 /* all checks complete - do it */
1034 vml->vma->vm_end = vml->vma->vm_start + new_len;
1036 askedalloc -= old_len;
1037 askedalloc += new_len;
1039 return vml->vma->vm_start;
1043 * Look up the first VMA which satisfies addr < vm_end, NULL if none
1045 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1047 struct vm_list_struct *vml;
1049 for (vml = mm->context.vmlist; vml; vml = vml->next)
1050 if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
1056 EXPORT_SYMBOL(find_vma);
1058 struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
1059 unsigned int foll_flags)
1064 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
1069 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1070 unsigned long to, unsigned long size, pgprot_t prot)
1072 vma->vm_start = vma->vm_pgoff << PAGE_SHIFT;
1075 EXPORT_SYMBOL(remap_pfn_range);
1077 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1081 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1082 unsigned long len, unsigned long pgoff, unsigned long flags)
1087 void arch_unmap_area(struct mm_struct *mm, unsigned long addr)
1091 void unmap_mapping_range(struct address_space *mapping,
1092 loff_t const holebegin, loff_t const holelen,
1096 EXPORT_SYMBOL(unmap_mapping_range);
1099 * Check that a process has enough memory to allocate a new virtual
1100 * mapping. 0 means there is enough memory for the allocation to
1101 * succeed and -ENOMEM implies there is not.
1103 * We currently support three overcommit policies, which are set via the
1104 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1106 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1107 * Additional code 2002 Jul 20 by Robert Love.
1109 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1111 * Note this is a helper function intended to be used by LSMs which
1112 * wish to use this logic.
1114 int __vm_enough_memory(long pages, int cap_sys_admin)
1116 unsigned long free, allowed;
1118 vm_acct_memory(pages);
1121 * Sometimes we want to use more memory than we have
1123 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1126 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1129 free = global_page_state(NR_FILE_PAGES);
1130 free += nr_swap_pages;
1133 * Any slabs which are created with the
1134 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1135 * which are reclaimable, under pressure. The dentry
1136 * cache and most inode caches should fall into this
1138 free += atomic_read(&slab_reclaim_pages);
1141 * Leave the last 3% for root
1150 * nr_free_pages() is very expensive on large systems,
1151 * only call if we're about to fail.
1153 n = nr_free_pages();
1156 * Leave reserved pages. The pages are not for anonymous pages.
1158 if (n <= totalreserve_pages)
1161 n -= totalreserve_pages;
1164 * Leave the last 3% for root
1176 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1178 * Leave the last 3% for root
1181 allowed -= allowed / 32;
1182 allowed += total_swap_pages;
1184 /* Don't let a single process grow too big:
1185 leave 3% of the size of this process for other processes */
1186 allowed -= current->mm->total_vm / 32;
1189 * cast `allowed' as a signed long because vm_committed_space
1190 * sometimes has a negative value
1192 if (atomic_read(&vm_committed_space) < (long)allowed)
1195 vm_unacct_memory(pages);
1200 int in_gate_area_no_task(unsigned long addr)
1205 struct page *filemap_nopage(struct vm_area_struct *area,
1206 unsigned long address, int *type)