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>
31 #include <asm/uaccess.h>
33 #include <asm/tlbflush.h>
37 unsigned long max_mapnr;
38 unsigned long num_physpages;
39 unsigned long askedalloc, realalloc;
40 atomic_t vm_committed_space = ATOMIC_INIT(0);
41 int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
42 int sysctl_overcommit_ratio = 50; /* default is 50% */
43 int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
44 int heap_stack_gap = 0;
46 EXPORT_SYMBOL(mem_map);
47 EXPORT_SYMBOL(sysctl_max_map_count);
48 EXPORT_SYMBOL(sysctl_overcommit_memory);
49 EXPORT_SYMBOL(sysctl_overcommit_ratio);
50 EXPORT_SYMBOL(vm_committed_space);
51 EXPORT_SYMBOL(__vm_enough_memory);
53 /* list of shareable VMAs */
54 struct rb_root nommu_vma_tree = RB_ROOT;
55 DECLARE_RWSEM(nommu_vma_sem);
57 struct vm_operations_struct generic_file_vm_ops = {
61 * Handle all mappings that got truncated by a "truncate()"
64 * NOTE! We have to be ready to update the memory sharing
65 * between the file and the memory map for a potential last
66 * incomplete page. Ugly, but necessary.
68 int vmtruncate(struct inode *inode, loff_t offset)
70 struct address_space *mapping = inode->i_mapping;
73 if (inode->i_size < offset)
75 i_size_write(inode, offset);
77 truncate_inode_pages(mapping, offset);
81 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
82 if (limit != RLIM_INFINITY && offset > limit)
84 if (offset > inode->i_sb->s_maxbytes)
86 i_size_write(inode, offset);
89 if (inode->i_op && inode->i_op->truncate)
90 inode->i_op->truncate(inode);
93 send_sig(SIGXFSZ, current, 0);
98 EXPORT_SYMBOL(vmtruncate);
101 * Return the total memory allocated for this pointer, not
102 * just what the caller asked for.
104 * Doesn't have to be accurate, i.e. may have races.
106 unsigned int kobjsize(const void *objp)
110 if (!objp || !((page = virt_to_page(objp))))
116 BUG_ON(page->index < 0);
117 BUG_ON(page->index >= MAX_ORDER);
119 return (PAGE_SIZE << page->index);
123 * The nommu dodgy version :-)
125 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
126 unsigned long start, int len, int write, int force,
127 struct page **pages, struct vm_area_struct **vmas)
130 static struct vm_area_struct dummy_vma;
132 for (i = 0; i < len; i++) {
134 pages[i] = virt_to_page(start);
136 page_cache_get(pages[i]);
139 vmas[i] = &dummy_vma;
145 DEFINE_RWLOCK(vmlist_lock);
146 struct vm_struct *vmlist;
148 void vfree(void *addr)
153 void *__vmalloc(unsigned long size, int gfp_mask, pgprot_t prot)
156 * kmalloc doesn't like __GFP_HIGHMEM for some reason
158 return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
161 struct page * vmalloc_to_page(void *addr)
163 return virt_to_page(addr);
166 unsigned long vmalloc_to_pfn(void *addr)
168 return page_to_pfn(virt_to_page(addr));
172 long vread(char *buf, char *addr, unsigned long count)
174 memcpy(buf, addr, count);
178 long vwrite(char *buf, char *addr, unsigned long count)
180 /* Don't allow overflow */
181 if ((unsigned long) addr + count < count)
182 count = -(unsigned long) addr;
184 memcpy(addr, buf, count);
189 * vmalloc - allocate virtually continguos memory
191 * @size: allocation size
193 * Allocate enough pages to cover @size from the page level
194 * allocator and map them into continguos kernel virtual space.
196 * For tight cotrol over page level allocator and protection flags
197 * use __vmalloc() instead.
199 void *vmalloc(unsigned long size)
201 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
205 * vmalloc_32 - allocate virtually continguos memory (32bit addressable)
207 * @size: allocation size
209 * Allocate enough 32bit PA addressable pages to cover @size from the
210 * page level allocator and map them into continguos kernel virtual space.
212 void *vmalloc_32(unsigned long size)
214 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
217 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
223 void vunmap(void *addr)
229 * sys_brk() for the most part doesn't need the global kernel
230 * lock, except when an application is doing something nasty
231 * like trying to un-brk an area that has already been mapped
232 * to a regular file. in this case, the unmapping will need
233 * to invoke file system routines that need the global lock.
235 asmlinkage unsigned long sys_brk(unsigned long brk)
237 struct mm_struct *mm = current->mm;
239 if (brk < mm->start_brk || brk > mm->context.end_brk)
246 * Always allow shrinking brk
248 if (brk <= mm->brk) {
254 * Ok, looks good - let it rip.
256 return mm->brk = brk;
260 static void show_process_blocks(void)
262 struct vm_list_struct *vml;
264 printk("Process blocks %d:", current->pid);
266 for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) {
267 printk(" %p: %p", vml, vml->vma);
269 printk(" (%d @%lx #%d)",
270 kobjsize((void *) vml->vma->vm_start),
272 atomic_read(&vml->vma->vm_usage));
273 printk(vml->next ? " ->" : ".\n");
278 static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
280 struct vm_area_struct *vma;
281 struct rb_node *n = nommu_vma_tree.rb_node;
284 vma = rb_entry(n, struct vm_area_struct, vm_rb);
286 if (start < vma->vm_start)
288 else if (start > vma->vm_start)
297 static void add_nommu_vma(struct vm_area_struct *vma)
299 struct vm_area_struct *pvma;
300 struct address_space *mapping;
301 struct rb_node **p = &nommu_vma_tree.rb_node;
302 struct rb_node *parent = NULL;
304 /* add the VMA to the mapping */
306 mapping = vma->vm_file->f_mapping;
308 flush_dcache_mmap_lock(mapping);
309 vma_prio_tree_insert(vma, &mapping->i_mmap);
310 flush_dcache_mmap_unlock(mapping);
313 /* add the VMA to the master list */
316 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
318 if (vma->vm_start < pvma->vm_start) {
321 else if (vma->vm_start > pvma->vm_start) {
325 /* mappings are at the same address - this can only
326 * happen for shared-mem chardevs and shared file
327 * mappings backed by ramfs/tmpfs */
328 BUG_ON(!(pvma->vm_flags & VM_SHARED));
339 rb_link_node(&vma->vm_rb, parent, p);
340 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
343 static void delete_nommu_vma(struct vm_area_struct *vma)
345 struct address_space *mapping;
347 /* remove the VMA from the mapping */
349 mapping = vma->vm_file->f_mapping;
351 flush_dcache_mmap_lock(mapping);
352 vma_prio_tree_remove(vma, &mapping->i_mmap);
353 flush_dcache_mmap_unlock(mapping);
356 /* remove from the master list */
357 rb_erase(&vma->vm_rb, &nommu_vma_tree);
361 * determine whether a mapping should be permitted and, if so, what sort of
362 * mapping we're capable of supporting
364 static int validate_mmap_request(struct file *file,
370 unsigned long *_capabilities)
372 unsigned long capabilities;
373 unsigned long reqprot = prot;
376 /* do the simple checks first */
377 if (flags & MAP_FIXED || addr) {
379 "%d: Can't do fixed-address/overlay mmap of RAM\n",
384 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
385 (flags & MAP_TYPE) != MAP_SHARED)
388 if (PAGE_ALIGN(len) == 0)
394 /* offset overflow? */
395 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
399 /* validate file mapping requests */
400 struct address_space *mapping;
402 /* files must support mmap */
403 if (!file->f_op || !file->f_op->mmap)
406 /* work out if what we've got could possibly be shared
407 * - we support chardevs that provide their own "memory"
408 * - we support files/blockdevs that are memory backed
410 mapping = file->f_mapping;
412 mapping = file->f_dentry->d_inode->i_mapping;
415 if (mapping && mapping->backing_dev_info)
416 capabilities = mapping->backing_dev_info->capabilities;
419 /* no explicit capabilities set, so assume some
421 switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
424 capabilities = BDI_CAP_MAP_COPY;
439 /* eliminate any capabilities that we can't support on this
441 if (!file->f_op->get_unmapped_area)
442 capabilities &= ~BDI_CAP_MAP_DIRECT;
443 if (!file->f_op->read)
444 capabilities &= ~BDI_CAP_MAP_COPY;
446 if (flags & MAP_SHARED) {
447 /* do checks for writing, appending and locking */
448 if ((prot & PROT_WRITE) &&
449 !(file->f_mode & FMODE_WRITE))
452 if (IS_APPEND(file->f_dentry->d_inode) &&
453 (file->f_mode & FMODE_WRITE))
456 if (locks_verify_locked(file->f_dentry->d_inode))
459 if (!(capabilities & BDI_CAP_MAP_DIRECT))
462 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
463 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
464 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
466 printk("MAP_SHARED not completely supported on !MMU\n");
470 /* we mustn't privatise shared mappings */
471 capabilities &= ~BDI_CAP_MAP_COPY;
474 /* we're going to read the file into private memory we
476 if (!(capabilities & BDI_CAP_MAP_COPY))
479 /* we don't permit a private writable mapping to be
480 * shared with the backing device */
481 if (prot & PROT_WRITE)
482 capabilities &= ~BDI_CAP_MAP_DIRECT;
485 /* handle executable mappings and implied executable
487 if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) {
488 if (prot & PROT_EXEC)
491 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
492 /* handle implication of PROT_EXEC by PROT_READ */
493 if (current->personality & READ_IMPLIES_EXEC) {
494 if (capabilities & BDI_CAP_EXEC_MAP)
498 else if ((prot & PROT_READ) &&
499 (prot & PROT_EXEC) &&
500 !(capabilities & BDI_CAP_EXEC_MAP)
502 /* backing file is not executable, try to copy */
503 capabilities &= ~BDI_CAP_MAP_DIRECT;
507 /* anonymous mappings are always memory backed and can be
510 capabilities = BDI_CAP_MAP_COPY;
512 /* handle PROT_EXEC implication by PROT_READ */
513 if ((prot & PROT_READ) &&
514 (current->personality & READ_IMPLIES_EXEC))
518 /* allow the security API to have its say */
519 ret = security_file_mmap(file, reqprot, prot, flags);
524 *_capabilities = capabilities;
529 * we've determined that we can make the mapping, now translate what we
530 * now know into VMA flags
532 static unsigned long determine_vm_flags(struct file *file,
535 unsigned long capabilities)
537 unsigned long vm_flags;
539 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
540 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
541 /* vm_flags |= mm->def_flags; */
543 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
544 /* attempt to share read-only copies of mapped file chunks */
545 if (file && !(prot & PROT_WRITE))
546 vm_flags |= VM_MAYSHARE;
549 /* overlay a shareable mapping on the backing device or inode
550 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
552 if (flags & MAP_SHARED)
553 vm_flags |= VM_MAYSHARE | VM_SHARED;
554 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
555 vm_flags |= VM_MAYSHARE;
558 /* refuse to let anyone share private mappings with this process if
559 * it's being traced - otherwise breakpoints set in it may interfere
560 * with another untraced process
562 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
563 vm_flags &= ~VM_MAYSHARE;
569 * set up a shared mapping on a file
571 static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
575 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
579 /* getting an ENOSYS error indicates that direct mmap isn't
580 * possible (as opposed to tried but failed) so we'll fall
581 * through to making a private copy of the data and mapping
587 * set up a private mapping or an anonymous shared mapping
589 static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
594 /* invoke the file's mapping function so that it can keep track of
595 * shared mappings on devices or memory
596 * - VM_MAYSHARE will be set if it may attempt to share
599 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
600 if (ret != -ENOSYS) {
601 /* shouldn't return success if we're not sharing */
602 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
603 return ret; /* success or a real error */
606 /* getting an ENOSYS error indicates that direct mmap isn't
607 * possible (as opposed to tried but failed) so we'll try to
608 * make a private copy of the data and map that instead */
611 /* allocate some memory to hold the mapping
612 * - note that this may not return a page-aligned address if the object
613 * we're allocating is smaller than a page
615 base = kmalloc(len, GFP_KERNEL);
619 vma->vm_start = (unsigned long) base;
620 vma->vm_end = vma->vm_start + len;
621 vma->vm_flags |= VM_MAPPED_COPY;
624 if (len + WARN_ON_SLACK <= kobjsize(result))
625 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
626 len, current->pid, kobjsize(result) - len);
630 /* read the contents of a file into the copy */
634 fpos = vma->vm_pgoff;
639 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
645 /* clear the last little bit */
647 memset(base + ret, 0, len - ret);
650 /* if it's an anonymous mapping, then just clear it */
651 memset(base, 0, len);
662 printk("Allocation of length %lu from process %d failed\n",
669 * handle mapping creation for uClinux
671 unsigned long do_mmap_pgoff(struct file *file,
678 struct vm_list_struct *vml = NULL;
679 struct vm_area_struct *vma = NULL;
681 unsigned long capabilities, vm_flags;
685 /* decide whether we should attempt the mapping, and if so what sort of
687 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
692 /* we've determined that we can make the mapping, now translate what we
693 * now know into VMA flags */
694 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
696 /* we're going to need to record the mapping if it works */
697 vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
699 goto error_getting_vml;
700 memset(vml, 0, sizeof(*vml));
702 down_write(&nommu_vma_sem);
704 /* if we want to share, we need to check for VMAs created by other
705 * mmap() calls that overlap with our proposed mapping
706 * - we can only share with an exact match on most regular files
707 * - shared mappings on character devices and memory backed files are
708 * permitted to overlap inexactly as far as we are concerned for in
709 * these cases, sharing is handled in the driver or filesystem rather
712 if (vm_flags & VM_MAYSHARE) {
713 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
714 unsigned long vmpglen;
716 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
717 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
719 if (!(vma->vm_flags & VM_MAYSHARE))
722 /* search for overlapping mappings on the same file */
723 if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
726 if (vma->vm_pgoff >= pgoff + pglen)
729 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
730 vmpglen >>= PAGE_SHIFT;
731 if (pgoff >= vma->vm_pgoff + vmpglen)
734 /* handle inexactly overlapping matches between mappings */
735 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
736 if (!(capabilities & BDI_CAP_MAP_DIRECT))
737 goto sharing_violation;
741 /* we've found a VMA we can share */
742 atomic_inc(&vma->vm_usage);
745 result = (void *) vma->vm_start;
751 /* obtain the address at which to make a shared mapping
752 * - this is the hook for quasi-memory character devices to
753 * tell us the location of a shared mapping
755 if (file && file->f_op->get_unmapped_area) {
756 addr = file->f_op->get_unmapped_area(file, addr, len,
758 if (IS_ERR((void *) addr)) {
760 if (ret != (unsigned long) -ENOSYS)
763 /* the driver refused to tell us where to site
764 * the mapping so we'll have to attempt to copy
766 ret = (unsigned long) -ENODEV;
767 if (!(capabilities & BDI_CAP_MAP_COPY))
770 capabilities &= ~BDI_CAP_MAP_DIRECT;
775 /* we're going to need a VMA struct as well */
776 vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
778 goto error_getting_vma;
780 memset(vma, 0, sizeof(*vma));
781 INIT_LIST_HEAD(&vma->anon_vma_node);
782 atomic_set(&vma->vm_usage, 1);
786 vma->vm_flags = vm_flags;
787 vma->vm_start = addr;
788 vma->vm_end = addr + len;
789 vma->vm_pgoff = pgoff;
793 /* set up the mapping */
794 if (file && vma->vm_flags & VM_SHARED)
795 ret = do_mmap_shared_file(vma, len);
797 ret = do_mmap_private(vma, len);
801 /* okay... we have a mapping; now we have to register it */
802 result = (void *) vma->vm_start;
804 if (vma->vm_flags & VM_MAPPED_COPY) {
805 realalloc += kobjsize(result);
809 realalloc += kobjsize(vma);
810 askedalloc += sizeof(*vma);
812 current->mm->total_vm += len >> PAGE_SHIFT;
817 realalloc += kobjsize(vml);
818 askedalloc += sizeof(*vml);
820 vml->next = current->mm->context.vmlist;
821 current->mm->context.vmlist = vml;
823 up_write(&nommu_vma_sem);
825 if (prot & PROT_EXEC)
826 flush_icache_range((unsigned long) result,
827 (unsigned long) result + len);
830 printk("do_mmap:\n");
831 show_process_blocks();
834 return (unsigned long) result;
837 up_write(&nommu_vma_sem);
846 up_write(&nommu_vma_sem);
847 printk("Attempt to share mismatched mappings\n");
852 up_write(&nommu_vma_sem);
854 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
860 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
867 * handle mapping disposal for uClinux
869 static void put_vma(struct vm_area_struct *vma)
872 down_write(&nommu_vma_sem);
874 if (atomic_dec_and_test(&vma->vm_usage)) {
875 delete_nommu_vma(vma);
877 if (vma->vm_ops && vma->vm_ops->close)
878 vma->vm_ops->close(vma);
880 /* IO memory and memory shared directly out of the pagecache from
881 * ramfs/tmpfs mustn't be released here */
882 if (vma->vm_flags & VM_MAPPED_COPY) {
883 realalloc -= kobjsize((void *) vma->vm_start);
884 askedalloc -= vma->vm_end - vma->vm_start;
885 kfree((void *) vma->vm_start);
888 realalloc -= kobjsize(vma);
889 askedalloc -= sizeof(*vma);
896 up_write(&nommu_vma_sem);
900 int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
902 struct vm_list_struct *vml, **parent;
903 unsigned long end = addr + len;
906 printk("do_munmap:\n");
909 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
910 if ((*parent)->vma->vm_start == addr &&
911 (*parent)->vma->vm_end == end)
914 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
915 current->pid, current->comm, (void *) addr);
924 realalloc -= kobjsize(vml);
925 askedalloc -= sizeof(*vml);
927 mm->total_vm -= len >> PAGE_SHIFT;
930 show_process_blocks();
936 /* Release all mmaps. */
937 void exit_mmap(struct mm_struct * mm)
939 struct vm_list_struct *tmp;
943 printk("Exit_mmap:\n");
948 while ((tmp = mm->context.vmlist)) {
949 mm->context.vmlist = tmp->next;
952 realalloc -= kobjsize(tmp);
953 askedalloc -= sizeof(*tmp);
958 show_process_blocks();
963 asmlinkage long sys_munmap(unsigned long addr, size_t len)
966 struct mm_struct *mm = current->mm;
968 down_write(&mm->mmap_sem);
969 ret = do_munmap(mm, addr, len);
970 up_write(&mm->mmap_sem);
974 unsigned long do_brk(unsigned long addr, unsigned long len)
980 * Expand (or shrink) an existing mapping, potentially moving it at the
981 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
983 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
984 * This option implies MREMAP_MAYMOVE.
986 * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
987 * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
989 unsigned long do_mremap(unsigned long addr,
990 unsigned long old_len, unsigned long new_len,
991 unsigned long flags, unsigned long new_addr)
993 struct vm_list_struct *vml = NULL;
995 /* insanity checks first */
997 return (unsigned long) -EINVAL;
999 if (flags & MREMAP_FIXED && new_addr != addr)
1000 return (unsigned long) -EINVAL;
1002 for (vml = current->mm->context.vmlist; vml; vml = vml->next)
1003 if (vml->vma->vm_start == addr)
1006 return (unsigned long) -EINVAL;
1009 if (vml->vma->vm_end != vml->vma->vm_start + old_len)
1010 return (unsigned long) -EFAULT;
1012 if (vml->vma->vm_flags & VM_MAYSHARE)
1013 return (unsigned long) -EPERM;
1015 if (new_len > kobjsize((void *) addr))
1016 return (unsigned long) -ENOMEM;
1018 /* all checks complete - do it */
1019 vml->vma->vm_end = vml->vma->vm_start + new_len;
1021 askedalloc -= old_len;
1022 askedalloc += new_len;
1024 return vml->vma->vm_start;
1028 * Look up the first VMA which satisfies addr < vm_end, NULL if none
1030 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1032 struct vm_list_struct *vml;
1034 for (vml = mm->context.vmlist; vml; vml = vml->next)
1035 if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
1041 EXPORT_SYMBOL(find_vma);
1043 struct page * follow_page(struct mm_struct *mm, unsigned long addr, int write)
1048 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
1053 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1054 unsigned long to, unsigned long size, pgprot_t prot)
1059 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1063 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1064 unsigned long len, unsigned long pgoff, unsigned long flags)
1069 void arch_unmap_area(struct vm_area_struct *area)
1073 void update_mem_hiwater(struct task_struct *tsk)
1075 unsigned long rss = get_mm_counter(tsk->mm, rss);
1077 if (likely(tsk->mm)) {
1078 if (tsk->mm->hiwater_rss < rss)
1079 tsk->mm->hiwater_rss = rss;
1080 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
1081 tsk->mm->hiwater_vm = tsk->mm->total_vm;
1085 void unmap_mapping_range(struct address_space *mapping,
1086 loff_t const holebegin, loff_t const holelen,
1092 * Check that a process has enough memory to allocate a new virtual
1093 * mapping. 0 means there is enough memory for the allocation to
1094 * succeed and -ENOMEM implies there is not.
1096 * We currently support three overcommit policies, which are set via the
1097 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1099 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1100 * Additional code 2002 Jul 20 by Robert Love.
1102 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1104 * Note this is a helper function intended to be used by LSMs which
1105 * wish to use this logic.
1107 int __vm_enough_memory(long pages, int cap_sys_admin)
1109 unsigned long free, allowed;
1111 vm_acct_memory(pages);
1114 * Sometimes we want to use more memory than we have
1116 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1119 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1122 free = get_page_cache_size();
1123 free += nr_swap_pages;
1126 * Any slabs which are created with the
1127 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1128 * which are reclaimable, under pressure. The dentry
1129 * cache and most inode caches should fall into this
1131 free += atomic_read(&slab_reclaim_pages);
1134 * Leave the last 3% for root
1143 * nr_free_pages() is very expensive on large systems,
1144 * only call if we're about to fail.
1146 n = nr_free_pages();
1153 vm_unacct_memory(pages);
1157 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1159 * Leave the last 3% for root
1162 allowed -= allowed / 32;
1163 allowed += total_swap_pages;
1165 /* Don't let a single process grow too big:
1166 leave 3% of the size of this process for other processes */
1167 allowed -= current->mm->total_vm / 32;
1169 if (atomic_read(&vm_committed_space) < allowed)
1172 vm_unacct_memory(pages);
1177 int in_gate_area_no_task(unsigned long addr)