--- /dev/null
+/*
+ * mm/mmap.c
+ *
+ * Written by obz.
+ *
+ * Address space accounting code <alan@redhat.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/shm.h>
+#include <linux/mman.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/syscalls.h>
+#include <linux/init.h>
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/personality.h>
+#include <linux/security.h>
+#include <linux/hugetlb.h>
+#include <linux/profile.h>
+#include <linux/module.h>
+#include <linux/mount.h>
+#include <linux/mempolicy.h>
+#include <linux/rmap.h>
+
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+#include <asm/cacheflush.h>
+#include <asm/tlb.h>
+
+/*
+ * WARNING: the debugging will use recursive algorithms so never enable this
+ * unless you know what you are doing.
+ */
+#undef DEBUG_MM_RB
+
+/* description of effects of mapping type and prot in current implementation.
+ * this is due to the limited x86 page protection hardware. The expected
+ * behavior is in parens:
+ *
+ * map_type prot
+ * PROT_NONE PROT_READ PROT_WRITE PROT_EXEC
+ * MAP_SHARED r: (no) no r: (yes) yes r: (no) yes r: (no) yes
+ * w: (no) no w: (no) no w: (yes) yes w: (no) no
+ * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
+ *
+ * MAP_PRIVATE r: (no) no r: (yes) yes r: (no) yes r: (no) yes
+ * w: (no) no w: (no) no w: (copy) copy w: (no) no
+ * x: (no) no x: (no) yes x: (no) yes x: (yes) yes
+ *
+ */
+pgprot_t protection_map[16] = {
+ __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
+ __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
+};
+
+int sysctl_overcommit_memory = 0; /* default is heuristic overcommit */
+int sysctl_overcommit_ratio = 50; /* default is 50% */
+int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
+atomic_t vm_committed_space = ATOMIC_INIT(0);
+
+EXPORT_SYMBOL(sysctl_overcommit_memory);
+EXPORT_SYMBOL(sysctl_overcommit_ratio);
+EXPORT_SYMBOL(sysctl_max_map_count);
+EXPORT_SYMBOL(vm_committed_space);
+
+/*
+ * Requires inode->i_mapping->i_mmap_lock
+ */
+static void __remove_shared_vm_struct(struct vm_area_struct *vma,
+ struct file *file, struct address_space *mapping)
+{
+ if (vma->vm_flags & VM_DENYWRITE)
+ atomic_inc(&file->f_dentry->d_inode->i_writecount);
+ if (vma->vm_flags & VM_SHARED)
+ mapping->i_mmap_writable--;
+
+ flush_dcache_mmap_lock(mapping);
+ if (unlikely(vma->vm_flags & VM_NONLINEAR))
+ list_del_init(&vma->shared.vm_set.list);
+ else
+ vma_prio_tree_remove(vma, &mapping->i_mmap);
+ flush_dcache_mmap_unlock(mapping);
+}
+
+/*
+ * Remove one vm structure and free it.
+ */
+static void remove_vm_struct(struct vm_area_struct *vma)
+{
+ struct file *file = vma->vm_file;
+
+ if (file) {
+ struct address_space *mapping = file->f_mapping;
+ spin_lock(&mapping->i_mmap_lock);
+ __remove_shared_vm_struct(vma, file, mapping);
+ spin_unlock(&mapping->i_mmap_lock);
+ }
+ if (vma->vm_ops && vma->vm_ops->close)
+ vma->vm_ops->close(vma);
+ if (file)
+ fput(file);
+ anon_vma_unlink(vma);
+ mpol_free(vma_policy(vma));
+ kmem_cache_free(vm_area_cachep, vma);
+}
+
+/*
+ * sys_brk() for the most part doesn't need the global kernel
+ * lock, except when an application is doing something nasty
+ * like trying to un-brk an area that has already been mapped
+ * to a regular file. in this case, the unmapping will need
+ * to invoke file system routines that need the global lock.
+ */
+asmlinkage unsigned long sys_brk(unsigned long brk)
+{
+ unsigned long rlim, retval;
+ unsigned long newbrk, oldbrk;
+ struct mm_struct *mm = current->mm;
+
+ down_write(&mm->mmap_sem);
+
+ if (brk < mm->end_code)
+ goto out;
+ newbrk = PAGE_ALIGN(brk);
+ oldbrk = PAGE_ALIGN(mm->brk);
+ if (oldbrk == newbrk)
+ goto set_brk;
+
+ /* Always allow shrinking brk. */
+ if (brk <= mm->brk) {
+ if (!do_munmap(mm, newbrk, oldbrk-newbrk))
+ goto set_brk;
+ goto out;
+ }
+
+ /* Check against rlimit.. */
+ rlim = current->rlim[RLIMIT_DATA].rlim_cur;
+ if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim)
+ goto out;
+
+ /* Check against existing mmap mappings. */
+ if (find_vma_intersection(mm, oldbrk, newbrk+PAGE_SIZE))
+ goto out;
+
+ /* Ok, looks good - let it rip. */
+ if (do_brk(oldbrk, newbrk-oldbrk) != oldbrk)
+ goto out;
+set_brk:
+ mm->brk = brk;
+out:
+ retval = mm->brk;
+ up_write(&mm->mmap_sem);
+ return retval;
+}
+
+#ifdef DEBUG_MM_RB
+static int browse_rb(struct rb_root *root)
+{
+ int i = 0, j;
+ struct rb_node *nd, *pn = NULL;
+ unsigned long prev = 0, pend = 0;
+
+ for (nd = rb_first(root); nd; nd = rb_next(nd)) {
+ struct vm_area_struct *vma;
+ vma = rb_entry(nd, struct vm_area_struct, vm_rb);
+ if (vma->vm_start < prev)
+ printk("vm_start %lx prev %lx\n", vma->vm_start, prev), i = -1;
+ if (vma->vm_start < pend)
+ printk("vm_start %lx pend %lx\n", vma->vm_start, pend);
+ if (vma->vm_start > vma->vm_end)
+ printk("vm_end %lx < vm_start %lx\n", vma->vm_end, vma->vm_start);
+ i++;
+ pn = nd;
+ }
+ j = 0;
+ for (nd = pn; nd; nd = rb_prev(nd)) {
+ j++;
+ }
+ if (i != j)
+ printk("backwards %d, forwards %d\n", j, i), i = 0;
+ return i;
+}
+
+void validate_mm(struct mm_struct *mm)
+{
+ int bug = 0;
+ int i = 0;
+ struct vm_area_struct *tmp = mm->mmap;
+ while (tmp) {
+ tmp = tmp->vm_next;
+ i++;
+ }
+ if (i != mm->map_count)
+ printk("map_count %d vm_next %d\n", mm->map_count, i), bug = 1;
+ i = browse_rb(&mm->mm_rb);
+ if (i != mm->map_count)
+ printk("map_count %d rb %d\n", mm->map_count, i), bug = 1;
+ if (bug)
+ BUG();
+}
+#else
+#define validate_mm(mm) do { } while (0)
+#endif
+
+static struct vm_area_struct *
+find_vma_prepare(struct mm_struct *mm, unsigned long addr,
+ struct vm_area_struct **pprev, struct rb_node ***rb_link,
+ struct rb_node ** rb_parent)
+{
+ struct vm_area_struct * vma;
+ struct rb_node ** __rb_link, * __rb_parent, * rb_prev;
+
+ __rb_link = &mm->mm_rb.rb_node;
+ rb_prev = __rb_parent = NULL;
+ vma = NULL;
+
+ while (*__rb_link) {
+ struct vm_area_struct *vma_tmp;
+
+ __rb_parent = *__rb_link;
+ vma_tmp = rb_entry(__rb_parent, struct vm_area_struct, vm_rb);
+
+ if (vma_tmp->vm_end > addr) {
+ vma = vma_tmp;
+ if (vma_tmp->vm_start <= addr)
+ return vma;
+ __rb_link = &__rb_parent->rb_left;
+ } else {
+ rb_prev = __rb_parent;
+ __rb_link = &__rb_parent->rb_right;
+ }
+ }
+
+ *pprev = NULL;
+ if (rb_prev)
+ *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb);
+ *rb_link = __rb_link;
+ *rb_parent = __rb_parent;
+ return vma;
+}
+
+static inline void
+__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct vm_area_struct *prev, struct rb_node *rb_parent)
+{
+ if (prev) {
+ vma->vm_next = prev->vm_next;
+ prev->vm_next = vma;
+ } else {
+ mm->mmap = vma;
+ if (rb_parent)
+ vma->vm_next = rb_entry(rb_parent,
+ struct vm_area_struct, vm_rb);
+ else
+ vma->vm_next = NULL;
+ }
+}
+
+void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct rb_node **rb_link, struct rb_node *rb_parent)
+{
+ rb_link_node(&vma->vm_rb, rb_parent, rb_link);
+ rb_insert_color(&vma->vm_rb, &mm->mm_rb);
+}
+
+static inline void __vma_link_file(struct vm_area_struct *vma)
+{
+ struct file * file;
+
+ file = vma->vm_file;
+ if (file) {
+ struct address_space *mapping = file->f_mapping;
+
+ if (vma->vm_flags & VM_DENYWRITE)
+ atomic_dec(&file->f_dentry->d_inode->i_writecount);
+ if (vma->vm_flags & VM_SHARED)
+ mapping->i_mmap_writable++;
+
+ flush_dcache_mmap_lock(mapping);
+ if (unlikely(vma->vm_flags & VM_NONLINEAR))
+ list_add_tail(&vma->shared.vm_set.list,
+ &mapping->i_mmap_nonlinear);
+ else
+ vma_prio_tree_insert(vma, &mapping->i_mmap);
+ flush_dcache_mmap_unlock(mapping);
+ }
+}
+
+static void
+__vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct vm_area_struct *prev, struct rb_node **rb_link,
+ struct rb_node *rb_parent)
+{
+ __vma_link_list(mm, vma, prev, rb_parent);
+ __vma_link_rb(mm, vma, rb_link, rb_parent);
+ __anon_vma_link(vma);
+}
+
+static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct vm_area_struct *prev, struct rb_node **rb_link,
+ struct rb_node *rb_parent)
+{
+ struct address_space *mapping = NULL;
+
+ if (vma->vm_file)
+ mapping = vma->vm_file->f_mapping;
+
+ if (mapping)
+ spin_lock(&mapping->i_mmap_lock);
+ anon_vma_lock(vma);
+
+ __vma_link(mm, vma, prev, rb_link, rb_parent);
+ __vma_link_file(vma);
+
+ anon_vma_unlock(vma);
+ if (mapping)
+ spin_unlock(&mapping->i_mmap_lock);
+
+ mark_mm_hugetlb(mm, vma);
+ mm->map_count++;
+ validate_mm(mm);
+}
+
+/*
+ * Helper for vma_adjust in the split_vma insert case:
+ * insert vm structure into list and rbtree and anon_vma,
+ * but it has already been inserted into prio_tree earlier.
+ */
+static void
+__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
+{
+ struct vm_area_struct * __vma, * prev;
+ struct rb_node ** rb_link, * rb_parent;
+
+ __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent);
+ if (__vma && __vma->vm_start < vma->vm_end)
+ BUG();
+ __vma_link(mm, vma, prev, rb_link, rb_parent);
+ mm->map_count++;
+}
+
+static inline void
+__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct vm_area_struct *prev)
+{
+ prev->vm_next = vma->vm_next;
+ rb_erase(&vma->vm_rb, &mm->mm_rb);
+ if (mm->mmap_cache == vma)
+ mm->mmap_cache = prev;
+}
+
+/*
+ * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that
+ * is already present in an i_mmap tree without adjusting the tree.
+ * The following helper function should be used when such adjustments
+ * are necessary. The "insert" vma (if any) is to be inserted
+ * before we drop the necessary locks.
+ */
+void vma_adjust(struct vm_area_struct *vma, unsigned long start,
+ unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ struct vm_area_struct *next = vma->vm_next;
+ struct address_space *mapping = NULL;
+ struct prio_tree_root *root = NULL;
+ struct file *file = vma->vm_file;
+ struct anon_vma *anon_vma = NULL;
+ long adjust_next = 0;
+ int remove_next = 0;
+
+ if (next && !insert) {
+ if (end >= next->vm_end) {
+ /*
+ * vma expands, overlapping all the next, and
+ * perhaps the one after too (mprotect case 6).
+ */
+again: remove_next = 1 + (end > next->vm_end);
+ end = next->vm_end;
+ anon_vma = next->anon_vma;
+ } else if (end > next->vm_start) {
+ /*
+ * vma expands, overlapping part of the next:
+ * mprotect case 5 shifting the boundary up.
+ */
+ adjust_next = (end - next->vm_start) >> PAGE_SHIFT;
+ anon_vma = next->anon_vma;
+ } else if (end < vma->vm_end) {
+ /*
+ * vma shrinks, and !insert tells it's not
+ * split_vma inserting another: so it must be
+ * mprotect case 4 shifting the boundary down.
+ */
+ adjust_next = - ((vma->vm_end - end) >> PAGE_SHIFT);
+ anon_vma = next->anon_vma;
+ }
+ }
+
+ if (file) {
+ mapping = file->f_mapping;
+ if (!(vma->vm_flags & VM_NONLINEAR))
+ root = &mapping->i_mmap;
+ spin_lock(&mapping->i_mmap_lock);
+ if (insert) {
+ /*
+ * Put into prio_tree now, so instantiated pages
+ * are visible to arm/parisc __flush_dcache_page
+ * throughout; but we cannot insert into address
+ * space until vma start or end is updated.
+ */
+ __vma_link_file(insert);
+ }
+ }
+
+ /*
+ * When changing only vma->vm_end, we don't really need
+ * anon_vma lock: but is that case worth optimizing out?
+ */
+ if (vma->anon_vma)
+ anon_vma = vma->anon_vma;
+ if (anon_vma)
+ spin_lock(&anon_vma->lock);
+
+ if (root) {
+ flush_dcache_mmap_lock(mapping);
+ vma_prio_tree_remove(vma, root);
+ if (adjust_next)
+ vma_prio_tree_remove(next, root);
+ }
+
+ vma->vm_start = start;
+ vma->vm_end = end;
+ vma->vm_pgoff = pgoff;
+ if (adjust_next) {
+ next->vm_start += adjust_next << PAGE_SHIFT;
+ next->vm_pgoff += adjust_next;
+ }
+
+ if (root) {
+ if (adjust_next) {
+ vma_prio_tree_init(next);
+ vma_prio_tree_insert(next, root);
+ }
+ vma_prio_tree_init(vma);
+ vma_prio_tree_insert(vma, root);
+ flush_dcache_mmap_unlock(mapping);
+ }
+
+ if (remove_next) {
+ /*
+ * vma_merge has merged next into vma, and needs
+ * us to remove next before dropping the locks.
+ */
+ __vma_unlink(mm, next, vma);
+ if (file)
+ __remove_shared_vm_struct(next, file, mapping);
+ if (next->anon_vma)
+ __anon_vma_merge(vma, next);
+ } else if (insert) {
+ /*
+ * split_vma has split insert from vma, and needs
+ * us to insert it before dropping the locks
+ * (it may either follow vma or precede it).
+ */
+ __insert_vm_struct(mm, insert);
+ }
+
+ if (anon_vma)
+ spin_unlock(&anon_vma->lock);
+ if (mapping)
+ spin_unlock(&mapping->i_mmap_lock);
+
+ if (remove_next) {
+ if (file)
+ fput(file);
+ mm->map_count--;
+ mpol_free(vma_policy(next));
+ kmem_cache_free(vm_area_cachep, next);
+ /*
+ * In mprotect's case 6 (see comments on vma_merge),
+ * we must remove another next too. It would clutter
+ * up the code too much to do both in one go.
+ */
+ if (remove_next == 2) {
+ next = vma->vm_next;
+ goto again;
+ }
+ }
+
+ validate_mm(mm);
+}
+
+/*
+ * If the vma has a ->close operation then the driver probably needs to release
+ * per-vma resources, so we don't attempt to merge those.
+ */
+#define VM_SPECIAL (VM_IO | VM_DONTCOPY | VM_DONTEXPAND | VM_RESERVED)
+
+static inline int is_mergeable_vma(struct vm_area_struct *vma,
+ struct file *file, unsigned long vm_flags)
+{
+ if (vma->vm_flags != vm_flags)
+ return 0;
+ if (vma->vm_file != file)
+ return 0;
+ if (vma->vm_ops && vma->vm_ops->close)
+ return 0;
+ return 1;
+}
+
+static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1,
+ struct anon_vma *anon_vma2)
+{
+ return !anon_vma1 || !anon_vma2 || (anon_vma1 == anon_vma2);
+}
+
+/*
+ * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
+ * in front of (at a lower virtual address and file offset than) the vma.
+ *
+ * We cannot merge two vmas if they have differently assigned (non-NULL)
+ * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
+ *
+ * We don't check here for the merged mmap wrapping around the end of pagecache
+ * indices (16TB on ia32) because do_mmap_pgoff() does not permit mmap's which
+ * wrap, nor mmaps which cover the final page at index -1UL.
+ */
+static int
+can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
+ struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
+{
+ if (is_mergeable_vma(vma, file, vm_flags) &&
+ is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
+ if (vma->vm_pgoff == vm_pgoff)
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff)
+ * beyond (at a higher virtual address and file offset than) the vma.
+ *
+ * We cannot merge two vmas if they have differently assigned (non-NULL)
+ * anon_vmas, nor if same anon_vma is assigned but offsets incompatible.
+ */
+static int
+can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
+ struct anon_vma *anon_vma, struct file *file, pgoff_t vm_pgoff)
+{
+ if (is_mergeable_vma(vma, file, vm_flags) &&
+ is_mergeable_anon_vma(anon_vma, vma->anon_vma)) {
+ pgoff_t vm_pglen;
+ vm_pglen = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+ if (vma->vm_pgoff + vm_pglen == vm_pgoff)
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
+ * whether that can be merged with its predecessor or its successor.
+ * Or both (it neatly fills a hole).
+ *
+ * In most cases - when called for mmap, brk or mremap - [addr,end) is
+ * certain not to be mapped by the time vma_merge is called; but when
+ * called for mprotect, it is certain to be already mapped (either at
+ * an offset within prev, or at the start of next), and the flags of
+ * this area are about to be changed to vm_flags - and the no-change
+ * case has already been eliminated.
+ *
+ * The following mprotect cases have to be considered, where AAAA is
+ * the area passed down from mprotect_fixup, never extending beyond one
+ * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after:
+ *
+ * AAAA AAAA AAAA AAAA
+ * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN PPPPNNNNXXXX
+ * cannot merge might become might become might become
+ * PPNNNNNNNNNN PPPPPPPPPPNN PPPPPPPPPPPP 6 or
+ * mmap, brk or case 4 below case 5 below PPPPPPPPXXXX 7 or
+ * mremap move: PPPPNNNNNNNN 8
+ * AAAA
+ * PPPP NNNN PPPPPPPPPPPP PPPPPPPPNNNN PPPPNNNNNNNN
+ * might become case 1 below case 2 below case 3 below
+ *
+ * Odd one out? Case 8, because it extends NNNN but needs flags of XXXX:
+ * mprotect_fixup updates vm_flags & vm_page_prot on successful return.
+ */
+struct vm_area_struct *vma_merge(struct mm_struct *mm,
+ struct vm_area_struct *prev, unsigned long addr,
+ unsigned long end, unsigned long vm_flags,
+ struct anon_vma *anon_vma, struct file *file,
+ pgoff_t pgoff, struct mempolicy *policy)
+{
+ pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
+ struct vm_area_struct *area, *next;
+
+ /*
+ * We later require that vma->vm_flags == vm_flags,
+ * so this tests vma->vm_flags & VM_SPECIAL, too.
+ */
+ if (vm_flags & VM_SPECIAL)
+ return NULL;
+
+ if (prev)
+ next = prev->vm_next;
+ else
+ next = mm->mmap;
+ area = next;
+ if (next && next->vm_end == end) /* cases 6, 7, 8 */
+ next = next->vm_next;
+
+ /*
+ * Can it merge with the predecessor?
+ */
+ if (prev && prev->vm_end == addr &&
+ mpol_equal(vma_policy(prev), policy) &&
+ can_vma_merge_after(prev, vm_flags,
+ anon_vma, file, pgoff)) {
+ /*
+ * OK, it can. Can we now merge in the successor as well?
+ */
+ if (next && end == next->vm_start &&
+ mpol_equal(policy, vma_policy(next)) &&
+ can_vma_merge_before(next, vm_flags,
+ anon_vma, file, pgoff+pglen) &&
+ is_mergeable_anon_vma(prev->anon_vma,
+ next->anon_vma)) {
+ /* cases 1, 6 */
+ vma_adjust(prev, prev->vm_start,
+ next->vm_end, prev->vm_pgoff, NULL);
+ } else /* cases 2, 5, 7 */
+ vma_adjust(prev, prev->vm_start,
+ end, prev->vm_pgoff, NULL);
+ return prev;
+ }
+
+ /*
+ * Can this new request be merged in front of next?
+ */
+ if (next && end == next->vm_start &&
+ mpol_equal(policy, vma_policy(next)) &&
+ can_vma_merge_before(next, vm_flags,
+ anon_vma, file, pgoff+pglen)) {
+ if (prev && addr < prev->vm_end) /* case 4 */
+ vma_adjust(prev, prev->vm_start,
+ addr, prev->vm_pgoff, NULL);
+ else /* cases 3, 8 */
+ vma_adjust(area, addr, next->vm_end,
+ next->vm_pgoff - pglen, NULL);
+ return area;
+ }
+
+ return NULL;
+}
+
+/*
+ * find_mergeable_anon_vma is used by anon_vma_prepare, to check
+ * neighbouring vmas for a suitable anon_vma, before it goes off
+ * to allocate a new anon_vma. It checks because a repetitive
+ * sequence of mprotects and faults may otherwise lead to distinct
+ * anon_vmas being allocated, preventing vma merge in subsequent
+ * mprotect.
+ */
+struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma)
+{
+ struct vm_area_struct *near;
+ unsigned long vm_flags;
+
+ near = vma->vm_next;
+ if (!near)
+ goto try_prev;
+
+ /*
+ * Since only mprotect tries to remerge vmas, match flags
+ * which might be mprotected into each other later on.
+ * Neither mlock nor madvise tries to remerge at present,
+ * so leave their flags as obstructing a merge.
+ */
+ vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
+ vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
+
+ if (near->anon_vma && vma->vm_end == near->vm_start &&
+ mpol_equal(vma_policy(vma), vma_policy(near)) &&
+ can_vma_merge_before(near, vm_flags,
+ NULL, vma->vm_file, vma->vm_pgoff +
+ ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT)))
+ return near->anon_vma;
+try_prev:
+ /*
+ * It is potentially slow to have to call find_vma_prev here.
+ * But it's only on the first write fault on the vma, not
+ * every time, and we could devise a way to avoid it later
+ * (e.g. stash info in next's anon_vma_node when assigning
+ * an anon_vma, or when trying vma_merge). Another time.
+ */
+ if (find_vma_prev(vma->vm_mm, vma->vm_start, &near) != vma)
+ BUG();
+ if (!near)
+ goto none;
+
+ vm_flags = vma->vm_flags & ~(VM_READ|VM_WRITE|VM_EXEC);
+ vm_flags |= near->vm_flags & (VM_READ|VM_WRITE|VM_EXEC);
+
+ if (near->anon_vma && near->vm_end == vma->vm_start &&
+ mpol_equal(vma_policy(near), vma_policy(vma)) &&
+ can_vma_merge_after(near, vm_flags,
+ NULL, vma->vm_file, vma->vm_pgoff))
+ return near->anon_vma;
+none:
+ /*
+ * There's no absolute need to look only at touching neighbours:
+ * we could search further afield for "compatible" anon_vmas.
+ * But it would probably just be a waste of time searching,
+ * or lead to too many vmas hanging off the same anon_vma.
+ * We're trying to allow mprotect remerging later on,
+ * not trying to minimize memory used for anon_vmas.
+ */
+ return NULL;
+}
+
+/*
+ * The caller must hold down_write(current->mm->mmap_sem).
+ */
+
+unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
+ unsigned long len, unsigned long prot,
+ unsigned long flags, unsigned long pgoff)
+{
+ struct mm_struct * mm = current->mm;
+ struct vm_area_struct * vma, * prev;
+ struct inode *inode;
+ unsigned int vm_flags;
+ int correct_wcount = 0;
+ int error;
+ struct rb_node ** rb_link, * rb_parent;
+ int accountable = 1;
+ unsigned long charged = 0;
+
+ if (file) {
+ if (is_file_hugepages(file))
+ accountable = 0;
+
+ if (!file->f_op || !file->f_op->mmap)
+ return -ENODEV;
+
+ if ((prot & PROT_EXEC) &&
+ (file->f_vfsmnt->mnt_flags & MNT_NOEXEC))
+ return -EPERM;
+ }
+
+ if (!len)
+ return addr;
+
+ /* Careful about overflows.. */
+ len = PAGE_ALIGN(len);
+ if (!len || len > TASK_SIZE)
+ return -EINVAL;
+
+ /* offset overflow? */
+ if ((pgoff + (len >> PAGE_SHIFT)) < pgoff)
+ return -EINVAL;
+
+ /* Too many mappings? */
+ if (mm->map_count > sysctl_max_map_count)
+ return -ENOMEM;
+
+ /* Obtain the address to map to. we verify (or select) it and ensure
+ * that it represents a valid section of the address space.
+ */
+ addr = get_unmapped_area(file, addr, len, pgoff, flags);
+ if (addr & ~PAGE_MASK)
+ return addr;
+
+ /* Do simple checking here so the lower-level routines won't have
+ * to. we assume access permissions have been handled by the open
+ * of the memory object, so we don't do any here.
+ */
+ vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
+ mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+
+ if (flags & MAP_LOCKED) {
+ if (!capable(CAP_IPC_LOCK))
+ return -EPERM;
+ vm_flags |= VM_LOCKED;
+ }
+ /* mlock MCL_FUTURE? */
+ if (vm_flags & VM_LOCKED) {
+ unsigned long locked = mm->locked_vm << PAGE_SHIFT;
+ locked += len;
+ if (locked > current->rlim[RLIMIT_MEMLOCK].rlim_cur)
+ return -EAGAIN;
+ }
+
+ inode = file ? file->f_dentry->d_inode : NULL;
+
+ if (file) {
+ switch (flags & MAP_TYPE) {
+ case MAP_SHARED:
+ if ((prot&PROT_WRITE) && !(file->f_mode&FMODE_WRITE))
+ return -EACCES;
+
+ /*
+ * Make sure we don't allow writing to an append-only
+ * file..
+ */
+ if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE))
+ return -EACCES;
+
+ /*
+ * Make sure there are no mandatory locks on the file.
+ */
+ if (locks_verify_locked(inode))
+ return -EAGAIN;
+
+ vm_flags |= VM_SHARED | VM_MAYSHARE;
+ if (!(file->f_mode & FMODE_WRITE))
+ vm_flags &= ~(VM_MAYWRITE | VM_SHARED);
+
+ /* fall through */
+ case MAP_PRIVATE:
+ if (!(file->f_mode & FMODE_READ))
+ return -EACCES;
+ break;
+
+ default:
+ return -EINVAL;
+ }
+ } else {
+ switch (flags & MAP_TYPE) {
+ case MAP_SHARED:
+ vm_flags |= VM_SHARED | VM_MAYSHARE;
+ break;
+ case MAP_PRIVATE:
+ /*
+ * Set pgoff according to addr for anon_vma.
+ */
+ pgoff = addr >> PAGE_SHIFT;
+ break;
+ default:
+ return -EINVAL;
+ }
+ }
+
+ error = security_file_mmap(file, prot, flags);
+ if (error)
+ return error;
+
+ /* Clear old maps */
+ error = -ENOMEM;
+munmap_back:
+ vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
+ if (vma && vma->vm_start < addr + len) {
+ if (do_munmap(mm, addr, len))
+ return -ENOMEM;
+ goto munmap_back;
+ }
+
+ /* Check against address space limit. */
+ if ((mm->total_vm << PAGE_SHIFT) + len
+ > current->rlim[RLIMIT_AS].rlim_cur)
+ return -ENOMEM;
+
+ if (accountable && (!(flags & MAP_NORESERVE) ||
+ sysctl_overcommit_memory > 1)) {
+ if (vm_flags & VM_SHARED) {
+ /* Check memory availability in shmem_file_setup? */
+ vm_flags |= VM_ACCOUNT;
+ } else if (vm_flags & VM_WRITE) {
+ /*
+ * Private writable mapping: check memory availability
+ */
+ charged = len >> PAGE_SHIFT;
+ if (security_vm_enough_memory(charged))
+ return -ENOMEM;
+ vm_flags |= VM_ACCOUNT;
+ }
+ }
+
+ /*
+ * Can we just expand an old private anonymous mapping?
+ * The VM_SHARED test is necessary because shmem_zero_setup
+ * will create the file object for a shared anonymous map below.
+ */
+ if (!file && !(vm_flags & VM_SHARED) &&
+ vma_merge(mm, prev, addr, addr + len, vm_flags,
+ NULL, NULL, pgoff, NULL))
+ goto out;
+
+ /*
+ * Determine the object being mapped and call the appropriate
+ * specific mapper. the address has already been validated, but
+ * not unmapped, but the maps are removed from the list.
+ */
+ vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+ if (!vma) {
+ error = -ENOMEM;
+ goto unacct_error;
+ }
+ memset(vma, 0, sizeof(*vma));
+
+ vma->vm_mm = mm;
+ vma->vm_start = addr;
+ vma->vm_end = addr + len;
+ vma->vm_flags = vm_flags;
+ vma->vm_page_prot = protection_map[vm_flags & 0x0f];
+ vma->vm_pgoff = pgoff;
+
+ if (file) {
+ error = -EINVAL;
+ if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
+ goto free_vma;
+ if (vm_flags & VM_DENYWRITE) {
+ error = deny_write_access(file);
+ if (error)
+ goto free_vma;
+ correct_wcount = 1;
+ }
+ vma->vm_file = file;
+ get_file(file);
+ error = file->f_op->mmap(file, vma);
+ if (error)
+ goto unmap_and_free_vma;
+ } else if (vm_flags & VM_SHARED) {
+ error = shmem_zero_setup(vma);
+ if (error)
+ goto free_vma;
+ }
+
+ /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform
+ * shmem_zero_setup (perhaps called through /dev/zero's ->mmap)
+ * that memory reservation must be checked; but that reservation
+ * belongs to shared memory object, not to vma: so now clear it.
+ */
+ if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT))
+ vma->vm_flags &= ~VM_ACCOUNT;
+
+ /* Can addr have changed??
+ *
+ * Answer: Yes, several device drivers can do it in their
+ * f_op->mmap method. -DaveM
+ */
+ addr = vma->vm_start;
+
+ if (!file || !vma_merge(mm, prev, addr, vma->vm_end,
+ vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) {
+ vma_link(mm, vma, prev, rb_link, rb_parent);
+ if (correct_wcount)
+ atomic_inc(&inode->i_writecount);
+ } else {
+ if (file) {
+ if (correct_wcount)
+ atomic_inc(&inode->i_writecount);
+ fput(file);
+ }
+ mpol_free(vma_policy(vma));
+ kmem_cache_free(vm_area_cachep, vma);
+ }
+out:
+ mm->total_vm += len >> PAGE_SHIFT;
+ if (vm_flags & VM_LOCKED) {
+ mm->locked_vm += len >> PAGE_SHIFT;
+ make_pages_present(addr, addr + len);
+ }
+ if (flags & MAP_POPULATE) {
+ up_write(&mm->mmap_sem);
+ sys_remap_file_pages(addr, len, 0,
+ pgoff, flags & MAP_NONBLOCK);
+ down_write(&mm->mmap_sem);
+ }
+ return addr;
+
+unmap_and_free_vma:
+ if (correct_wcount)
+ atomic_inc(&inode->i_writecount);
+ vma->vm_file = NULL;
+ fput(file);
+
+ /* Undo any partial mapping done by a device driver. */
+ zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
+free_vma:
+ kmem_cache_free(vm_area_cachep, vma);
+unacct_error:
+ if (charged)
+ vm_unacct_memory(charged);
+ return error;
+}
+
+EXPORT_SYMBOL(do_mmap_pgoff);
+
+/* Get an address range which is currently unmapped.
+ * For shmat() with addr=0.
+ *
+ * Ugly calling convention alert:
+ * Return value with the low bits set means error value,
+ * ie
+ * if (ret & ~PAGE_MASK)
+ * error = ret;
+ *
+ * This function "knows" that -ENOMEM has the bits set.
+ */
+#ifndef HAVE_ARCH_UNMAPPED_AREA
+static inline unsigned long
+arch_get_unmapped_area(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
+ unsigned long start_addr;
+
+ if (len > TASK_SIZE)
+ return -ENOMEM;
+
+ if (addr) {
+ addr = PAGE_ALIGN(addr);
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ return addr;
+ }
+ start_addr = addr = mm->free_area_cache;
+
+full_search:
+ for (vma = find_vma(mm, addr); ; vma = vma->vm_next) {
+ /* At this point: (!vma || addr < vma->vm_end). */
+ if (TASK_SIZE - len < addr) {
+ /*
+ * Start a new search - just in case we missed
+ * some holes.
+ */
+ if (start_addr != TASK_UNMAPPED_BASE) {
+ start_addr = addr = TASK_UNMAPPED_BASE;
+ goto full_search;
+ }
+ return -ENOMEM;
+ }
+ if (!vma || addr + len <= vma->vm_start) {
+ /*
+ * Remember the place where we stopped the search:
+ */
+ mm->free_area_cache = addr + len;
+ return addr;
+ }
+ addr = vma->vm_end;
+ }
+}
+#else
+extern unsigned long
+arch_get_unmapped_area(struct file *, unsigned long, unsigned long,
+ unsigned long, unsigned long);
+#endif
+
+#ifndef HAVE_ARCH_CHECK_FIXED_MAPPING
+#define arch_check_fixed_mapping(_file,_addr,_len,_pgoff,_flags) 0
+#else
+extern unsigned long
+arch_check_fixed_mapping(struct file *, unsigned long, unsigned long,
+ unsigned long, unsigned long);
+#endif
+
+unsigned long
+get_unmapped_area(struct file *file, unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ if (flags & MAP_FIXED) {
+ unsigned long ret;
+
+ if (addr > TASK_SIZE - len)
+ return -ENOMEM;
+ if (addr & ~PAGE_MASK)
+ return -EINVAL;
+ ret = arch_check_fixed_mapping(file, addr, len, pgoff, flags);
+ if (ret != 0)
+ return ret;
+ if (file && is_file_hugepages(file)) {
+ /*
+ * Check if the given range is hugepage aligned, and
+ * can be made suitable for hugepages.
+ */
+ ret = prepare_hugepage_range(addr, len);
+ } else {
+ /*
+ * Ensure that a normal request is not falling in a
+ * reserved hugepage range. For some archs like IA-64,
+ * there is a separate region for hugepages.
+ */
+ ret = is_hugepage_only_range(addr, len);
+ }
+ if (ret)
+ return -EINVAL;
+ return addr;
+ }
+
+ if (file && file->f_op && file->f_op->get_unmapped_area)
+ return file->f_op->get_unmapped_area(file, addr, len,
+ pgoff, flags);
+
+ return arch_get_unmapped_area(file, addr, len, pgoff, flags);
+}
+
+EXPORT_SYMBOL(get_unmapped_area);
+
+/* Look up the first VMA which satisfies addr < vm_end, NULL if none. */
+struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr)
+{
+ struct vm_area_struct *vma = NULL;
+
+ if (mm) {
+ /* Check the cache first. */
+ /* (Cache hit rate is typically around 35%.) */
+ vma = mm->mmap_cache;
+ if (!(vma && vma->vm_end > addr && vma->vm_start <= addr)) {
+ struct rb_node * rb_node;
+
+ rb_node = mm->mm_rb.rb_node;
+ vma = NULL;
+
+ while (rb_node) {
+ struct vm_area_struct * vma_tmp;
+
+ vma_tmp = rb_entry(rb_node,
+ struct vm_area_struct, vm_rb);
+
+ if (vma_tmp->vm_end > addr) {
+ vma = vma_tmp;
+ if (vma_tmp->vm_start <= addr)
+ break;
+ rb_node = rb_node->rb_left;
+ } else
+ rb_node = rb_node->rb_right;
+ }
+ if (vma)
+ mm->mmap_cache = vma;
+ }
+ }
+ return vma;
+}
+
+EXPORT_SYMBOL(find_vma);
+
+/* Same as find_vma, but also return a pointer to the previous VMA in *pprev. */
+struct vm_area_struct *
+find_vma_prev(struct mm_struct *mm, unsigned long addr,
+ struct vm_area_struct **pprev)
+{
+ struct vm_area_struct *vma = NULL, *prev = NULL;
+ struct rb_node * rb_node;
+ if (!mm)
+ goto out;
+
+ /* Guard against addr being lower than the first VMA */
+ vma = mm->mmap;
+
+ /* Go through the RB tree quickly. */
+ rb_node = mm->mm_rb.rb_node;
+
+ while (rb_node) {
+ struct vm_area_struct *vma_tmp;
+ vma_tmp = rb_entry(rb_node, struct vm_area_struct, vm_rb);
+
+ if (addr < vma_tmp->vm_end) {
+ rb_node = rb_node->rb_left;
+ } else {
+ prev = vma_tmp;
+ if (!prev->vm_next || (addr < prev->vm_next->vm_end))
+ break;
+ rb_node = rb_node->rb_right;
+ }
+ }
+
+out:
+ *pprev = prev;
+ return prev ? prev->vm_next : vma;
+}
+
+#ifdef CONFIG_STACK_GROWSUP
+/*
+ * vma is the first one with address > vma->vm_end. Have to extend vma.
+ */
+int expand_stack(struct vm_area_struct * vma, unsigned long address)
+{
+ unsigned long grow;
+
+ if (!(vma->vm_flags & VM_GROWSUP))
+ return -EFAULT;
+
+ /*
+ * We must make sure the anon_vma is allocated
+ * so that the anon_vma locking is not a noop.
+ */
+ if (unlikely(anon_vma_prepare(vma)))
+ return -ENOMEM;
+ anon_vma_lock(vma);
+
+ /*
+ * vma->vm_start/vm_end cannot change under us because the caller
+ * is required to hold the mmap_sem in read mode. We need the
+ * anon_vma lock to serialize against concurrent expand_stacks.
+ */
+ address += 4 + PAGE_SIZE - 1;
+ address &= PAGE_MASK;
+ grow = (address - vma->vm_end) >> PAGE_SHIFT;
+
+ /* Overcommit.. */
+ if (security_vm_enough_memory(grow)) {
+ anon_vma_unlock(vma);
+ return -ENOMEM;
+ }
+
+ if (address - vma->vm_start > current->rlim[RLIMIT_STACK].rlim_cur ||
+ ((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) >
+ current->rlim[RLIMIT_AS].rlim_cur) {
+ anon_vma_unlock(vma);
+ vm_unacct_memory(grow);
+ return -ENOMEM;
+ }
+ vma->vm_end = address;
+ vma->vm_mm->total_vm += grow;
+ if (vma->vm_flags & VM_LOCKED)
+ vma->vm_mm->locked_vm += grow;
+ anon_vma_unlock(vma);
+ return 0;
+}
+
+struct vm_area_struct *
+find_extend_vma(struct mm_struct *mm, unsigned long addr)
+{
+ struct vm_area_struct *vma, *prev;
+
+ addr &= PAGE_MASK;
+ vma = find_vma_prev(mm, addr, &prev);
+ if (vma && (vma->vm_start <= addr))
+ return vma;
+ if (!prev || expand_stack(prev, addr))
+ return NULL;
+ if (prev->vm_flags & VM_LOCKED) {
+ make_pages_present(addr, prev->vm_end);
+ }
+ return prev;
+}
+#else
+/*
+ * vma is the first one with address < vma->vm_start. Have to extend vma.
+ */
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+ unsigned long grow;
+
+ /*
+ * We must make sure the anon_vma is allocated
+ * so that the anon_vma locking is not a noop.
+ */
+ if (unlikely(anon_vma_prepare(vma)))
+ return -ENOMEM;
+ anon_vma_lock(vma);
+
+ /*
+ * vma->vm_start/vm_end cannot change under us because the caller
+ * is required to hold the mmap_sem in read mode. We need the
+ * anon_vma lock to serialize against concurrent expand_stacks.
+ */
+ address &= PAGE_MASK;
+ grow = (vma->vm_start - address) >> PAGE_SHIFT;
+
+ /* Overcommit.. */
+ if (security_vm_enough_memory(grow)) {
+ anon_vma_unlock(vma);
+ return -ENOMEM;
+ }
+
+ if (vma->vm_end - address > current->rlim[RLIMIT_STACK].rlim_cur ||
+ ((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) >
+ current->rlim[RLIMIT_AS].rlim_cur) {
+ anon_vma_unlock(vma);
+ vm_unacct_memory(grow);
+ return -ENOMEM;
+ }
+ vma->vm_start = address;
+ vma->vm_pgoff -= grow;
+ vma->vm_mm->total_vm += grow;
+ if (vma->vm_flags & VM_LOCKED)
+ vma->vm_mm->locked_vm += grow;
+ anon_vma_unlock(vma);
+ return 0;
+}
+
+struct vm_area_struct *
+find_extend_vma(struct mm_struct * mm, unsigned long addr)
+{
+ struct vm_area_struct * vma;
+ unsigned long start;
+
+ addr &= PAGE_MASK;
+ vma = find_vma(mm,addr);
+ if (!vma)
+ return NULL;
+ if (vma->vm_start <= addr)
+ return vma;
+ if (!(vma->vm_flags & VM_GROWSDOWN))
+ return NULL;
+ start = vma->vm_start;
+ if (expand_stack(vma, addr))
+ return NULL;
+ if (vma->vm_flags & VM_LOCKED) {
+ make_pages_present(addr, start);
+ }
+ return vma;
+}
+#endif
+
+/*
+ * Try to free as many page directory entries as we can,
+ * without having to work very hard at actually scanning
+ * the page tables themselves.
+ *
+ * Right now we try to free page tables if we have a nice
+ * PGDIR-aligned area that got free'd up. We could be more
+ * granular if we want to, but this is fast and simple,
+ * and covers the bad cases.
+ *
+ * "prev", if it exists, points to a vma before the one
+ * we just free'd - but there's no telling how much before.
+ */
+static void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *prev,
+ unsigned long start, unsigned long end)
+{
+ unsigned long first = start & PGDIR_MASK;
+ unsigned long last = end + PGDIR_SIZE - 1;
+ unsigned long start_index, end_index;
+ struct mm_struct *mm = tlb->mm;
+
+ if (!prev) {
+ prev = mm->mmap;
+ if (!prev)
+ goto no_mmaps;
+ if (prev->vm_end > start) {
+ if (last > prev->vm_start)
+ last = prev->vm_start;
+ goto no_mmaps;
+ }
+ }
+ for (;;) {
+ struct vm_area_struct *next = prev->vm_next;
+
+ if (next) {
+ if (next->vm_start < start) {
+ prev = next;
+ continue;
+ }
+ if (last > next->vm_start)
+ last = next->vm_start;
+ }
+ if (prev->vm_end > first)
+ first = prev->vm_end + PGDIR_SIZE - 1;
+ break;
+ }
+no_mmaps:
+ if (last < first) /* for arches with discontiguous pgd indices */
+ return;
+ /*
+ * If the PGD bits are not consecutive in the virtual address, the
+ * old method of shifting the VA >> by PGDIR_SHIFT doesn't work.
+ */
+ start_index = pgd_index(first);
+ if (start_index < FIRST_USER_PGD_NR)
+ start_index = FIRST_USER_PGD_NR;
+ end_index = pgd_index(last);
+ if (end_index > start_index) {
+ clear_page_tables(tlb, start_index, end_index - start_index);
+ flush_tlb_pgtables(mm, first & PGDIR_MASK, last & PGDIR_MASK);
+ }
+}
+
+/* Normal function to fix up a mapping
+ * This function is the default for when an area has no specific
+ * function. This may be used as part of a more specific routine.
+ *
+ * By the time this function is called, the area struct has been
+ * removed from the process mapping list.
+ */
+static void unmap_vma(struct mm_struct *mm, struct vm_area_struct *area)
+{
+ size_t len = area->vm_end - area->vm_start;
+
+ area->vm_mm->total_vm -= len >> PAGE_SHIFT;
+ if (area->vm_flags & VM_LOCKED)
+ area->vm_mm->locked_vm -= len >> PAGE_SHIFT;
+ /*
+ * Is this a new hole at the lowest possible address?
+ */
+ if (area->vm_start >= TASK_UNMAPPED_BASE &&
+ area->vm_start < area->vm_mm->free_area_cache)
+ area->vm_mm->free_area_cache = area->vm_start;
+
+ remove_vm_struct(area);
+}
+
+/*
+ * Update the VMA and inode share lists.
+ *
+ * Ok - we have the memory areas we should free on the 'free' list,
+ * so release them, and do the vma updates.
+ */
+static void unmap_vma_list(struct mm_struct *mm,
+ struct vm_area_struct *mpnt)
+{
+ do {
+ struct vm_area_struct *next = mpnt->vm_next;
+ unmap_vma(mm, mpnt);
+ mpnt = next;
+ } while (mpnt != NULL);
+ validate_mm(mm);
+}
+
+/*
+ * Get rid of page table information in the indicated region.
+ *
+ * Called with the page table lock held.
+ */
+static void unmap_region(struct mm_struct *mm,
+ struct vm_area_struct *vma,
+ struct vm_area_struct *prev,
+ unsigned long start,
+ unsigned long end)
+{
+ struct mmu_gather *tlb;
+ unsigned long nr_accounted = 0;
+
+ lru_add_drain();
+ tlb = tlb_gather_mmu(mm, 0);
+ unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL);
+ vm_unacct_memory(nr_accounted);
+
+ if (is_hugepage_only_range(start, end - start))
+ hugetlb_free_pgtables(tlb, prev, start, end);
+ else
+ free_pgtables(tlb, prev, start, end);
+ tlb_finish_mmu(tlb, start, end);
+}
+
+/*
+ * Create a list of vma's touched by the unmap, removing them from the mm's
+ * vma list as we go..
+ */
+static void
+detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
+ struct vm_area_struct *prev, unsigned long end)
+{
+ struct vm_area_struct **insertion_point;
+ struct vm_area_struct *tail_vma = NULL;
+
+ insertion_point = (prev ? &prev->vm_next : &mm->mmap);
+ do {
+ rb_erase(&vma->vm_rb, &mm->mm_rb);
+ mm->map_count--;
+ tail_vma = vma;
+ vma = vma->vm_next;
+ } while (vma && vma->vm_start < end);
+ *insertion_point = vma;
+ tail_vma->vm_next = NULL;
+ mm->mmap_cache = NULL; /* Kill the cache. */
+}
+
+/*
+ * Split a vma into two pieces at address 'addr', a new vma is allocated
+ * either for the first part or the the tail.
+ */
+int split_vma(struct mm_struct * mm, struct vm_area_struct * vma,
+ unsigned long addr, int new_below)
+{
+ struct mempolicy *pol;
+ struct vm_area_struct *new;
+
+ if (mm->map_count >= sysctl_max_map_count)
+ return -ENOMEM;
+
+ new = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+ if (!new)
+ return -ENOMEM;
+
+ /* most fields are the same, copy all, and then fixup */
+ *new = *vma;
+ vma_prio_tree_init(new);
+
+ if (new_below)
+ new->vm_end = addr;
+ else {
+ new->vm_start = addr;
+ new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT);
+ }
+
+ pol = mpol_copy(vma_policy(vma));
+ if (IS_ERR(pol)) {
+ kmem_cache_free(vm_area_cachep, new);
+ return PTR_ERR(pol);
+ }
+ vma_set_policy(new, pol);
+
+ if (new->vm_file)
+ get_file(new->vm_file);
+
+ if (new->vm_ops && new->vm_ops->open)
+ new->vm_ops->open(new);
+
+ if (new_below)
+ vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff +
+ ((addr - new->vm_start) >> PAGE_SHIFT), new);
+ else
+ vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new);
+
+ return 0;
+}
+
+/* Munmap is split into 2 main parts -- this part which finds
+ * what needs doing, and the areas themselves, which do the
+ * work. This now handles partial unmappings.
+ * Jeremy Fitzhardinge <jeremy@goop.org>
+ */
+int do_munmap(struct mm_struct *mm, unsigned long start, size_t len)
+{
+ unsigned long end;
+ struct vm_area_struct *mpnt, *prev, *last;
+
+ if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE-start)
+ return -EINVAL;
+
+ if ((len = PAGE_ALIGN(len)) == 0)
+ return -EINVAL;
+
+ /* Find the first overlapping VMA */
+ mpnt = find_vma_prev(mm, start, &prev);
+ if (!mpnt)
+ return 0;
+ /* we have start < mpnt->vm_end */
+
+ if (is_vm_hugetlb_page(mpnt)) {
+ int ret = is_aligned_hugepage_range(start, len);
+
+ if (ret)
+ return ret;
+ }
+
+ /* if it doesn't overlap, we have nothing.. */
+ end = start + len;
+ if (mpnt->vm_start >= end)
+ return 0;
+
+ /* Something will probably happen, so notify. */
+ if (mpnt->vm_file && (mpnt->vm_flags & VM_EXEC))
+ profile_exec_unmap(mm);
+
+ /*
+ * If we need to split any vma, do it now to save pain later.
+ *
+ * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially
+ * unmapped vm_area_struct will remain in use: so lower split_vma
+ * places tmp vma above, and higher split_vma places tmp vma below.
+ */
+ if (start > mpnt->vm_start) {
+ if (split_vma(mm, mpnt, start, 0))
+ return -ENOMEM;
+ prev = mpnt;
+ }
+
+ /* Does it split the last one? */
+ last = find_vma(mm, end);
+ if (last && end > last->vm_start) {
+ if (split_vma(mm, last, end, 1))
+ return -ENOMEM;
+ }
+ mpnt = prev? prev->vm_next: mm->mmap;
+
+ /*
+ * Remove the vma's, and unmap the actual pages
+ */
+ detach_vmas_to_be_unmapped(mm, mpnt, prev, end);
+ spin_lock(&mm->page_table_lock);
+ unmap_region(mm, mpnt, prev, start, end);
+ spin_unlock(&mm->page_table_lock);
+
+ /* Fix up all other VM information */
+ unmap_vma_list(mm, mpnt);
+
+ return 0;
+}
+
+EXPORT_SYMBOL(do_munmap);
+
+asmlinkage long sys_munmap(unsigned long addr, size_t len)
+{
+ int ret;
+ struct mm_struct *mm = current->mm;
+
+ down_write(&mm->mmap_sem);
+ ret = do_munmap(mm, addr, len);
+ up_write(&mm->mmap_sem);
+ return ret;
+}
+
+/*
+ * this is really a simplified "do_mmap". it only handles
+ * anonymous maps. eventually we may be able to do some
+ * brk-specific accounting here.
+ */
+unsigned long do_brk(unsigned long addr, unsigned long len)
+{
+ struct mm_struct * mm = current->mm;
+ struct vm_area_struct * vma, * prev;
+ unsigned long flags;
+ struct rb_node ** rb_link, * rb_parent;
+ pgoff_t pgoff = addr >> PAGE_SHIFT;
+
+ len = PAGE_ALIGN(len);
+ if (!len)
+ return addr;
+
+ if ((addr + len) > TASK_SIZE || (addr + len) < addr)
+ return -EINVAL;
+
+ /*
+ * mlock MCL_FUTURE?
+ */
+ if (mm->def_flags & VM_LOCKED) {
+ unsigned long locked = mm->locked_vm << PAGE_SHIFT;
+ locked += len;
+ if (locked > current->rlim[RLIMIT_MEMLOCK].rlim_cur)
+ return -EAGAIN;
+ }
+
+ /*
+ * Clear old maps. this also does some error checking for us
+ */
+ munmap_back:
+ vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
+ if (vma && vma->vm_start < addr + len) {
+ if (do_munmap(mm, addr, len))
+ return -ENOMEM;
+ goto munmap_back;
+ }
+
+ /* Check against address space limits *after* clearing old maps... */
+ if ((mm->total_vm << PAGE_SHIFT) + len
+ > current->rlim[RLIMIT_AS].rlim_cur)
+ return -ENOMEM;
+
+ if (mm->map_count > sysctl_max_map_count)
+ return -ENOMEM;
+
+ if (security_vm_enough_memory(len >> PAGE_SHIFT))
+ return -ENOMEM;
+
+ flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags;
+
+ /* Can we just expand an old private anonymous mapping? */
+ if (vma_merge(mm, prev, addr, addr + len, flags,
+ NULL, NULL, pgoff, NULL))
+ goto out;
+
+ /*
+ * create a vma struct for an anonymous mapping
+ */
+ vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+ if (!vma) {
+ vm_unacct_memory(len >> PAGE_SHIFT);
+ return -ENOMEM;
+ }
+ memset(vma, 0, sizeof(*vma));
+
+ vma->vm_mm = mm;
+ vma->vm_start = addr;
+ vma->vm_end = addr + len;
+ vma->vm_pgoff = pgoff;
+ vma->vm_flags = flags;
+ vma->vm_page_prot = protection_map[flags & 0x0f];
+ vma_link(mm, vma, prev, rb_link, rb_parent);
+out:
+ mm->total_vm += len >> PAGE_SHIFT;
+ if (flags & VM_LOCKED) {
+ mm->locked_vm += len >> PAGE_SHIFT;
+ make_pages_present(addr, addr + len);
+ }
+ return addr;
+}
+
+EXPORT_SYMBOL(do_brk);
+
+/* Release all mmaps. */
+void exit_mmap(struct mm_struct *mm)
+{
+ struct mmu_gather *tlb;
+ struct vm_area_struct *vma;
+ unsigned long nr_accounted = 0;
+
+ profile_exit_mmap(mm);
+
+ lru_add_drain();
+
+ spin_lock(&mm->page_table_lock);
+
+ tlb = tlb_gather_mmu(mm, 1);
+ flush_cache_mm(mm);
+ /* Use ~0UL here to ensure all VMAs in the mm are unmapped */
+ mm->map_count -= unmap_vmas(&tlb, mm, mm->mmap, 0,
+ ~0UL, &nr_accounted, NULL);
+ vm_unacct_memory(nr_accounted);
+ BUG_ON(mm->map_count); /* This is just debugging */
+ clear_page_tables(tlb, FIRST_USER_PGD_NR, USER_PTRS_PER_PGD);
+ tlb_finish_mmu(tlb, 0, MM_VM_SIZE(mm));
+
+ vma = mm->mmap;
+ mm->mmap = mm->mmap_cache = NULL;
+ mm->mm_rb = RB_ROOT;
+ mm->rss = 0;
+ mm->total_vm = 0;
+ mm->locked_vm = 0;
+
+ spin_unlock(&mm->page_table_lock);
+
+ /*
+ * Walk the list again, actually closing and freeing it
+ * without holding any MM locks.
+ */
+ while (vma) {
+ struct vm_area_struct *next = vma->vm_next;
+ remove_vm_struct(vma);
+ vma = next;
+ }
+}
+
+/* Insert vm structure into process list sorted by address
+ * and into the inode's i_mmap tree. If vm_file is non-NULL
+ * then i_mmap_lock is taken here.
+ */
+void insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma)
+{
+ struct vm_area_struct * __vma, * prev;
+ struct rb_node ** rb_link, * rb_parent;
+
+ /*
+ * The vm_pgoff of a purely anonymous vma should be irrelevant
+ * until its first write fault, when page's anon_vma and index
+ * are set. But now set the vm_pgoff it will almost certainly
+ * end up with (unless mremap moves it elsewhere before that
+ * first wfault), so /proc/pid/maps tells a consistent story.
+ *
+ * By setting it to reflect the virtual start address of the
+ * vma, merges and splits can happen in a seamless way, just
+ * using the existing file pgoff checks and manipulations.
+ * Similarly in do_mmap_pgoff and in do_brk.
+ */
+ if (!vma->vm_file) {
+ BUG_ON(vma->anon_vma);
+ vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT;
+ }
+ __vma = find_vma_prepare(mm,vma->vm_start,&prev,&rb_link,&rb_parent);
+ if (__vma && __vma->vm_start < vma->vm_end)
+ BUG();
+ vma_link(mm, vma, prev, rb_link, rb_parent);
+}
+
+/*
+ * Copy the vma structure to a new location in the same mm,
+ * prior to moving page table entries, to effect an mremap move.
+ */
+struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
+ unsigned long addr, unsigned long len, pgoff_t pgoff)
+{
+ struct vm_area_struct *vma = *vmap;
+ unsigned long vma_start = vma->vm_start;
+ struct mm_struct *mm = vma->vm_mm;
+ struct vm_area_struct *new_vma, *prev;
+ struct rb_node **rb_link, *rb_parent;
+ struct mempolicy *pol;
+
+ /*
+ * If anonymous vma has not yet been faulted, update new pgoff
+ * to match new location, to increase its chance of merging.
+ */
+ if (!vma->vm_file && !vma->anon_vma)
+ pgoff = addr >> PAGE_SHIFT;
+
+ find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
+ new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
+ vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma));
+ if (new_vma) {
+ /*
+ * Source vma may have been merged into new_vma
+ */
+ if (vma_start >= new_vma->vm_start &&
+ vma_start < new_vma->vm_end)
+ *vmap = new_vma;
+ } else {
+ new_vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+ if (new_vma) {
+ *new_vma = *vma;
+ vma_prio_tree_init(new_vma);
+ pol = mpol_copy(vma_policy(vma));
+ if (IS_ERR(pol)) {
+ kmem_cache_free(vm_area_cachep, new_vma);
+ return NULL;
+ }
+ vma_set_policy(new_vma, pol);
+ new_vma->vm_start = addr;
+ new_vma->vm_end = addr + len;
+ new_vma->vm_pgoff = pgoff;
+ if (new_vma->vm_file)
+ get_file(new_vma->vm_file);
+ if (new_vma->vm_ops && new_vma->vm_ops->open)
+ new_vma->vm_ops->open(new_vma);
+ vma_link(mm, new_vma, prev, rb_link, rb_parent);
+ }
+ }
+ return new_vma;
+}
projects / xen.git / commitdiff