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, unsigned int __nocast gfp_mask,
157 * kmalloc doesn't like __GFP_HIGHMEM for some reason
159 return kmalloc(size, gfp_mask & ~__GFP_HIGHMEM);
162 struct page * vmalloc_to_page(void *addr)
164 return virt_to_page(addr);
167 unsigned long vmalloc_to_pfn(void *addr)
169 return page_to_pfn(virt_to_page(addr));
173 long vread(char *buf, char *addr, unsigned long count)
175 memcpy(buf, addr, count);
179 long vwrite(char *buf, char *addr, unsigned long count)
181 /* Don't allow overflow */
182 if ((unsigned long) addr + count < count)
183 count = -(unsigned long) addr;
185 memcpy(addr, buf, count);
190 * vmalloc - allocate virtually continguos memory
192 * @size: allocation size
194 * Allocate enough pages to cover @size from the page level
195 * allocator and map them into continguos kernel virtual space.
197 * For tight cotrol over page level allocator and protection flags
198 * use __vmalloc() instead.
200 void *vmalloc(unsigned long size)
202 return __vmalloc(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL);
206 * vmalloc_32 - allocate virtually continguos memory (32bit addressable)
208 * @size: allocation size
210 * Allocate enough 32bit PA addressable pages to cover @size from the
211 * page level allocator and map them into continguos kernel virtual space.
213 void *vmalloc_32(unsigned long size)
215 return __vmalloc(size, GFP_KERNEL, PAGE_KERNEL);
218 void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
224 void vunmap(void *addr)
230 * sys_brk() for the most part doesn't need the global kernel
231 * lock, except when an application is doing something nasty
232 * like trying to un-brk an area that has already been mapped
233 * to a regular file. in this case, the unmapping will need
234 * to invoke file system routines that need the global lock.
236 asmlinkage unsigned long sys_brk(unsigned long brk)
238 struct mm_struct *mm = current->mm;
240 if (brk < mm->start_brk || brk > mm->context.end_brk)
247 * Always allow shrinking brk
249 if (brk <= mm->brk) {
255 * Ok, looks good - let it rip.
257 return mm->brk = brk;
261 static void show_process_blocks(void)
263 struct vm_list_struct *vml;
265 printk("Process blocks %d:", current->pid);
267 for (vml = ¤t->mm->context.vmlist; vml; vml = vml->next) {
268 printk(" %p: %p", vml, vml->vma);
270 printk(" (%d @%lx #%d)",
271 kobjsize((void *) vml->vma->vm_start),
273 atomic_read(&vml->vma->vm_usage));
274 printk(vml->next ? " ->" : ".\n");
279 static inline struct vm_area_struct *find_nommu_vma(unsigned long start)
281 struct vm_area_struct *vma;
282 struct rb_node *n = nommu_vma_tree.rb_node;
285 vma = rb_entry(n, struct vm_area_struct, vm_rb);
287 if (start < vma->vm_start)
289 else if (start > vma->vm_start)
298 static void add_nommu_vma(struct vm_area_struct *vma)
300 struct vm_area_struct *pvma;
301 struct address_space *mapping;
302 struct rb_node **p = &nommu_vma_tree.rb_node;
303 struct rb_node *parent = NULL;
305 /* add the VMA to the mapping */
307 mapping = vma->vm_file->f_mapping;
309 flush_dcache_mmap_lock(mapping);
310 vma_prio_tree_insert(vma, &mapping->i_mmap);
311 flush_dcache_mmap_unlock(mapping);
314 /* add the VMA to the master list */
317 pvma = rb_entry(parent, struct vm_area_struct, vm_rb);
319 if (vma->vm_start < pvma->vm_start) {
322 else if (vma->vm_start > pvma->vm_start) {
326 /* mappings are at the same address - this can only
327 * happen for shared-mem chardevs and shared file
328 * mappings backed by ramfs/tmpfs */
329 BUG_ON(!(pvma->vm_flags & VM_SHARED));
340 rb_link_node(&vma->vm_rb, parent, p);
341 rb_insert_color(&vma->vm_rb, &nommu_vma_tree);
344 static void delete_nommu_vma(struct vm_area_struct *vma)
346 struct address_space *mapping;
348 /* remove the VMA from the mapping */
350 mapping = vma->vm_file->f_mapping;
352 flush_dcache_mmap_lock(mapping);
353 vma_prio_tree_remove(vma, &mapping->i_mmap);
354 flush_dcache_mmap_unlock(mapping);
357 /* remove from the master list */
358 rb_erase(&vma->vm_rb, &nommu_vma_tree);
362 * determine whether a mapping should be permitted and, if so, what sort of
363 * mapping we're capable of supporting
365 static int validate_mmap_request(struct file *file,
371 unsigned long *_capabilities)
373 unsigned long capabilities;
374 unsigned long reqprot = prot;
377 /* do the simple checks first */
378 if (flags & MAP_FIXED || addr) {
380 "%d: Can't do fixed-address/overlay mmap of RAM\n",
385 if ((flags & MAP_TYPE) != MAP_PRIVATE &&
386 (flags & MAP_TYPE) != MAP_SHARED)
389 if (PAGE_ALIGN(len) == 0)
395 /* offset overflow? */
396 if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
400 /* validate file mapping requests */
401 struct address_space *mapping;
403 /* files must support mmap */
404 if (!file->f_op || !file->f_op->mmap)
407 /* work out if what we've got could possibly be shared
408 * - we support chardevs that provide their own "memory"
409 * - we support files/blockdevs that are memory backed
411 mapping = file->f_mapping;
413 mapping = file->f_dentry->d_inode->i_mapping;
416 if (mapping && mapping->backing_dev_info)
417 capabilities = mapping->backing_dev_info->capabilities;
420 /* no explicit capabilities set, so assume some
422 switch (file->f_dentry->d_inode->i_mode & S_IFMT) {
425 capabilities = BDI_CAP_MAP_COPY;
440 /* eliminate any capabilities that we can't support on this
442 if (!file->f_op->get_unmapped_area)
443 capabilities &= ~BDI_CAP_MAP_DIRECT;
444 if (!file->f_op->read)
445 capabilities &= ~BDI_CAP_MAP_COPY;
447 if (flags & MAP_SHARED) {
448 /* do checks for writing, appending and locking */
449 if ((prot & PROT_WRITE) &&
450 !(file->f_mode & FMODE_WRITE))
453 if (IS_APPEND(file->f_dentry->d_inode) &&
454 (file->f_mode & FMODE_WRITE))
457 if (locks_verify_locked(file->f_dentry->d_inode))
460 if (!(capabilities & BDI_CAP_MAP_DIRECT))
463 if (((prot & PROT_READ) && !(capabilities & BDI_CAP_READ_MAP)) ||
464 ((prot & PROT_WRITE) && !(capabilities & BDI_CAP_WRITE_MAP)) ||
465 ((prot & PROT_EXEC) && !(capabilities & BDI_CAP_EXEC_MAP))
467 printk("MAP_SHARED not completely supported on !MMU\n");
471 /* we mustn't privatise shared mappings */
472 capabilities &= ~BDI_CAP_MAP_COPY;
475 /* we're going to read the file into private memory we
477 if (!(capabilities & BDI_CAP_MAP_COPY))
480 /* we don't permit a private writable mapping to be
481 * shared with the backing device */
482 if (prot & PROT_WRITE)
483 capabilities &= ~BDI_CAP_MAP_DIRECT;
486 /* handle executable mappings and implied executable
488 if (file->f_vfsmnt->mnt_flags & MNT_NOEXEC) {
489 if (prot & PROT_EXEC)
492 else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
493 /* handle implication of PROT_EXEC by PROT_READ */
494 if (current->personality & READ_IMPLIES_EXEC) {
495 if (capabilities & BDI_CAP_EXEC_MAP)
499 else if ((prot & PROT_READ) &&
500 (prot & PROT_EXEC) &&
501 !(capabilities & BDI_CAP_EXEC_MAP)
503 /* backing file is not executable, try to copy */
504 capabilities &= ~BDI_CAP_MAP_DIRECT;
508 /* anonymous mappings are always memory backed and can be
511 capabilities = BDI_CAP_MAP_COPY;
513 /* handle PROT_EXEC implication by PROT_READ */
514 if ((prot & PROT_READ) &&
515 (current->personality & READ_IMPLIES_EXEC))
519 /* allow the security API to have its say */
520 ret = security_file_mmap(file, reqprot, prot, flags);
525 *_capabilities = capabilities;
530 * we've determined that we can make the mapping, now translate what we
531 * now know into VMA flags
533 static unsigned long determine_vm_flags(struct file *file,
536 unsigned long capabilities)
538 unsigned long vm_flags;
540 vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
541 vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
542 /* vm_flags |= mm->def_flags; */
544 if (!(capabilities & BDI_CAP_MAP_DIRECT)) {
545 /* attempt to share read-only copies of mapped file chunks */
546 if (file && !(prot & PROT_WRITE))
547 vm_flags |= VM_MAYSHARE;
550 /* overlay a shareable mapping on the backing device or inode
551 * if possible - used for chardevs, ramfs/tmpfs/shmfs and
553 if (flags & MAP_SHARED)
554 vm_flags |= VM_MAYSHARE | VM_SHARED;
555 else if ((((vm_flags & capabilities) ^ vm_flags) & BDI_CAP_VMFLAGS) == 0)
556 vm_flags |= VM_MAYSHARE;
559 /* refuse to let anyone share private mappings with this process if
560 * it's being traced - otherwise breakpoints set in it may interfere
561 * with another untraced process
563 if ((flags & MAP_PRIVATE) && (current->ptrace & PT_PTRACED))
564 vm_flags &= ~VM_MAYSHARE;
570 * set up a shared mapping on a file
572 static int do_mmap_shared_file(struct vm_area_struct *vma, unsigned long len)
576 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
580 /* getting an ENOSYS error indicates that direct mmap isn't
581 * possible (as opposed to tried but failed) so we'll fall
582 * through to making a private copy of the data and mapping
588 * set up a private mapping or an anonymous shared mapping
590 static int do_mmap_private(struct vm_area_struct *vma, unsigned long len)
595 /* invoke the file's mapping function so that it can keep track of
596 * shared mappings on devices or memory
597 * - VM_MAYSHARE will be set if it may attempt to share
600 ret = vma->vm_file->f_op->mmap(vma->vm_file, vma);
601 if (ret != -ENOSYS) {
602 /* shouldn't return success if we're not sharing */
603 BUG_ON(ret == 0 && !(vma->vm_flags & VM_MAYSHARE));
604 return ret; /* success or a real error */
607 /* getting an ENOSYS error indicates that direct mmap isn't
608 * possible (as opposed to tried but failed) so we'll try to
609 * make a private copy of the data and map that instead */
612 /* allocate some memory to hold the mapping
613 * - note that this may not return a page-aligned address if the object
614 * we're allocating is smaller than a page
616 base = kmalloc(len, GFP_KERNEL);
620 vma->vm_start = (unsigned long) base;
621 vma->vm_end = vma->vm_start + len;
622 vma->vm_flags |= VM_MAPPED_COPY;
625 if (len + WARN_ON_SLACK <= kobjsize(result))
626 printk("Allocation of %lu bytes from process %d has %lu bytes of slack\n",
627 len, current->pid, kobjsize(result) - len);
631 /* read the contents of a file into the copy */
635 fpos = vma->vm_pgoff;
640 ret = vma->vm_file->f_op->read(vma->vm_file, base, len, &fpos);
646 /* clear the last little bit */
648 memset(base + ret, 0, len - ret);
651 /* if it's an anonymous mapping, then just clear it */
652 memset(base, 0, len);
663 printk("Allocation of length %lu from process %d failed\n",
670 * handle mapping creation for uClinux
672 unsigned long do_mmap_pgoff(struct file *file,
679 struct vm_list_struct *vml = NULL;
680 struct vm_area_struct *vma = NULL;
682 unsigned long capabilities, vm_flags;
686 /* decide whether we should attempt the mapping, and if so what sort of
688 ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
693 /* we've determined that we can make the mapping, now translate what we
694 * now know into VMA flags */
695 vm_flags = determine_vm_flags(file, prot, flags, capabilities);
697 /* we're going to need to record the mapping if it works */
698 vml = kmalloc(sizeof(struct vm_list_struct), GFP_KERNEL);
700 goto error_getting_vml;
701 memset(vml, 0, sizeof(*vml));
703 down_write(&nommu_vma_sem);
705 /* if we want to share, we need to check for VMAs created by other
706 * mmap() calls that overlap with our proposed mapping
707 * - we can only share with an exact match on most regular files
708 * - shared mappings on character devices and memory backed files are
709 * permitted to overlap inexactly as far as we are concerned for in
710 * these cases, sharing is handled in the driver or filesystem rather
713 if (vm_flags & VM_MAYSHARE) {
714 unsigned long pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
715 unsigned long vmpglen;
717 for (rb = rb_first(&nommu_vma_tree); rb; rb = rb_next(rb)) {
718 vma = rb_entry(rb, struct vm_area_struct, vm_rb);
720 if (!(vma->vm_flags & VM_MAYSHARE))
723 /* search for overlapping mappings on the same file */
724 if (vma->vm_file->f_dentry->d_inode != file->f_dentry->d_inode)
727 if (vma->vm_pgoff >= pgoff + pglen)
730 vmpglen = vma->vm_end - vma->vm_start + PAGE_SIZE - 1;
731 vmpglen >>= PAGE_SHIFT;
732 if (pgoff >= vma->vm_pgoff + vmpglen)
735 /* handle inexactly overlapping matches between mappings */
736 if (vma->vm_pgoff != pgoff || vmpglen != pglen) {
737 if (!(capabilities & BDI_CAP_MAP_DIRECT))
738 goto sharing_violation;
742 /* we've found a VMA we can share */
743 atomic_inc(&vma->vm_usage);
746 result = (void *) vma->vm_start;
752 /* obtain the address at which to make a shared mapping
753 * - this is the hook for quasi-memory character devices to
754 * tell us the location of a shared mapping
756 if (file && file->f_op->get_unmapped_area) {
757 addr = file->f_op->get_unmapped_area(file, addr, len,
759 if (IS_ERR((void *) addr)) {
761 if (ret != (unsigned long) -ENOSYS)
764 /* the driver refused to tell us where to site
765 * the mapping so we'll have to attempt to copy
767 ret = (unsigned long) -ENODEV;
768 if (!(capabilities & BDI_CAP_MAP_COPY))
771 capabilities &= ~BDI_CAP_MAP_DIRECT;
776 /* we're going to need a VMA struct as well */
777 vma = kmalloc(sizeof(struct vm_area_struct), GFP_KERNEL);
779 goto error_getting_vma;
781 memset(vma, 0, sizeof(*vma));
782 INIT_LIST_HEAD(&vma->anon_vma_node);
783 atomic_set(&vma->vm_usage, 1);
787 vma->vm_flags = vm_flags;
788 vma->vm_start = addr;
789 vma->vm_end = addr + len;
790 vma->vm_pgoff = pgoff;
794 /* set up the mapping */
795 if (file && vma->vm_flags & VM_SHARED)
796 ret = do_mmap_shared_file(vma, len);
798 ret = do_mmap_private(vma, len);
802 /* okay... we have a mapping; now we have to register it */
803 result = (void *) vma->vm_start;
805 if (vma->vm_flags & VM_MAPPED_COPY) {
806 realalloc += kobjsize(result);
810 realalloc += kobjsize(vma);
811 askedalloc += sizeof(*vma);
813 current->mm->total_vm += len >> PAGE_SHIFT;
818 realalloc += kobjsize(vml);
819 askedalloc += sizeof(*vml);
821 vml->next = current->mm->context.vmlist;
822 current->mm->context.vmlist = vml;
824 up_write(&nommu_vma_sem);
826 if (prot & PROT_EXEC)
827 flush_icache_range((unsigned long) result,
828 (unsigned long) result + len);
831 printk("do_mmap:\n");
832 show_process_blocks();
835 return (unsigned long) result;
838 up_write(&nommu_vma_sem);
847 up_write(&nommu_vma_sem);
848 printk("Attempt to share mismatched mappings\n");
853 up_write(&nommu_vma_sem);
855 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
861 printk("Allocation of vml for %lu byte allocation from process %d failed\n",
868 * handle mapping disposal for uClinux
870 static void put_vma(struct vm_area_struct *vma)
873 down_write(&nommu_vma_sem);
875 if (atomic_dec_and_test(&vma->vm_usage)) {
876 delete_nommu_vma(vma);
878 if (vma->vm_ops && vma->vm_ops->close)
879 vma->vm_ops->close(vma);
881 /* IO memory and memory shared directly out of the pagecache from
882 * ramfs/tmpfs mustn't be released here */
883 if (vma->vm_flags & VM_MAPPED_COPY) {
884 realalloc -= kobjsize((void *) vma->vm_start);
885 askedalloc -= vma->vm_end - vma->vm_start;
886 kfree((void *) vma->vm_start);
889 realalloc -= kobjsize(vma);
890 askedalloc -= sizeof(*vma);
897 up_write(&nommu_vma_sem);
901 int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len)
903 struct vm_list_struct *vml, **parent;
904 unsigned long end = addr + len;
907 printk("do_munmap:\n");
910 for (parent = &mm->context.vmlist; *parent; parent = &(*parent)->next)
911 if ((*parent)->vma->vm_start == addr &&
912 (*parent)->vma->vm_end == end)
915 printk("munmap of non-mmaped memory by process %d (%s): %p\n",
916 current->pid, current->comm, (void *) addr);
925 realalloc -= kobjsize(vml);
926 askedalloc -= sizeof(*vml);
928 mm->total_vm -= len >> PAGE_SHIFT;
931 show_process_blocks();
937 /* Release all mmaps. */
938 void exit_mmap(struct mm_struct * mm)
940 struct vm_list_struct *tmp;
944 printk("Exit_mmap:\n");
949 while ((tmp = mm->context.vmlist)) {
950 mm->context.vmlist = tmp->next;
953 realalloc -= kobjsize(tmp);
954 askedalloc -= sizeof(*tmp);
959 show_process_blocks();
964 asmlinkage long sys_munmap(unsigned long addr, size_t len)
967 struct mm_struct *mm = current->mm;
969 down_write(&mm->mmap_sem);
970 ret = do_munmap(mm, addr, len);
971 up_write(&mm->mmap_sem);
975 unsigned long do_brk(unsigned long addr, unsigned long len)
981 * Expand (or shrink) an existing mapping, potentially moving it at the
982 * same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
984 * MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
985 * This option implies MREMAP_MAYMOVE.
987 * on uClinux, we only permit changing a mapping's size, and only as long as it stays within the
988 * hole allocated by the kmalloc() call in do_mmap_pgoff() and the block is not shareable
990 unsigned long do_mremap(unsigned long addr,
991 unsigned long old_len, unsigned long new_len,
992 unsigned long flags, unsigned long new_addr)
994 struct vm_list_struct *vml = NULL;
996 /* insanity checks first */
998 return (unsigned long) -EINVAL;
1000 if (flags & MREMAP_FIXED && new_addr != addr)
1001 return (unsigned long) -EINVAL;
1003 for (vml = current->mm->context.vmlist; vml; vml = vml->next)
1004 if (vml->vma->vm_start == addr)
1007 return (unsigned long) -EINVAL;
1010 if (vml->vma->vm_end != vml->vma->vm_start + old_len)
1011 return (unsigned long) -EFAULT;
1013 if (vml->vma->vm_flags & VM_MAYSHARE)
1014 return (unsigned long) -EPERM;
1016 if (new_len > kobjsize((void *) addr))
1017 return (unsigned long) -ENOMEM;
1019 /* all checks complete - do it */
1020 vml->vma->vm_end = vml->vma->vm_start + new_len;
1022 askedalloc -= old_len;
1023 askedalloc += new_len;
1025 return vml->vma->vm_start;
1029 * Look up the first VMA which satisfies addr < vm_end, NULL if none
1031 struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
1033 struct vm_list_struct *vml;
1035 for (vml = mm->context.vmlist; vml; vml = vml->next)
1036 if (addr >= vml->vma->vm_start && addr < vml->vma->vm_end)
1042 EXPORT_SYMBOL(find_vma);
1044 struct page * follow_page(struct mm_struct *mm, unsigned long addr, int write)
1049 struct vm_area_struct *find_extend_vma(struct mm_struct *mm, unsigned long addr)
1054 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1055 unsigned long to, unsigned long size, pgprot_t prot)
1060 void swap_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1064 unsigned long arch_get_unmapped_area(struct file *file, unsigned long addr,
1065 unsigned long len, unsigned long pgoff, unsigned long flags)
1070 void arch_unmap_area(struct vm_area_struct *area)
1074 void update_mem_hiwater(struct task_struct *tsk)
1076 unsigned long rss = get_mm_counter(tsk->mm, rss);
1078 if (likely(tsk->mm)) {
1079 if (tsk->mm->hiwater_rss < rss)
1080 tsk->mm->hiwater_rss = rss;
1081 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
1082 tsk->mm->hiwater_vm = tsk->mm->total_vm;
1086 void unmap_mapping_range(struct address_space *mapping,
1087 loff_t const holebegin, loff_t const holelen,
1093 * Check that a process has enough memory to allocate a new virtual
1094 * mapping. 0 means there is enough memory for the allocation to
1095 * succeed and -ENOMEM implies there is not.
1097 * We currently support three overcommit policies, which are set via the
1098 * vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting
1100 * Strict overcommit modes added 2002 Feb 26 by Alan Cox.
1101 * Additional code 2002 Jul 20 by Robert Love.
1103 * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise.
1105 * Note this is a helper function intended to be used by LSMs which
1106 * wish to use this logic.
1108 int __vm_enough_memory(long pages, int cap_sys_admin)
1110 unsigned long free, allowed;
1112 vm_acct_memory(pages);
1115 * Sometimes we want to use more memory than we have
1117 if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS)
1120 if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) {
1123 free = get_page_cache_size();
1124 free += nr_swap_pages;
1127 * Any slabs which are created with the
1128 * SLAB_RECLAIM_ACCOUNT flag claim to have contents
1129 * which are reclaimable, under pressure. The dentry
1130 * cache and most inode caches should fall into this
1132 free += atomic_read(&slab_reclaim_pages);
1135 * Leave the last 3% for root
1144 * nr_free_pages() is very expensive on large systems,
1145 * only call if we're about to fail.
1147 n = nr_free_pages();
1154 vm_unacct_memory(pages);
1158 allowed = totalram_pages * sysctl_overcommit_ratio / 100;
1160 * Leave the last 3% for root
1163 allowed -= allowed / 32;
1164 allowed += total_swap_pages;
1166 /* Don't let a single process grow too big:
1167 leave 3% of the size of this process for other processes */
1168 allowed -= current->mm->total_vm / 32;
1170 if (atomic_read(&vm_committed_space) < allowed)
1173 vm_unacct_memory(pages);
1178 int in_gate_area_no_task(unsigned long addr)