| /* |
| * linux/mm/mmap.c |
| * |
| * Written by obz. |
| */ |
| #include <linux/slab.h> |
| #include <linux/shm.h> |
| #include <linux/mman.h> |
| #include <linux/pagemap.h> |
| #include <linux/swap.h> |
| #include <linux/swapctl.h> |
| #include <linux/smp_lock.h> |
| #include <linux/init.h> |
| #include <linux/file.h> |
| #include <linux/fs.h> |
| #include <linux/personality.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/pgalloc.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; |
| int max_map_count = DEFAULT_MAX_MAP_COUNT; |
| |
| /* Check that a process has enough memory to allocate a |
| * new virtual mapping. |
| */ |
| int vm_enough_memory(long pages) |
| { |
| /* Stupid algorithm to decide if we have enough memory: while |
| * simple, it hopefully works in most obvious cases.. Easy to |
| * fool it, but this should catch most mistakes. |
| */ |
| /* 23/11/98 NJC: Somewhat less stupid version of algorithm, |
| * which tries to do "TheRightThing". Instead of using half of |
| * (buffers+cache), use the minimum values. Allow an extra 2% |
| * of num_physpages for safety margin. |
| */ |
| |
| unsigned long free; |
| |
| /* Sometimes we want to use more memory than we have. */ |
| if (sysctl_overcommit_memory) |
| return 1; |
| |
| /* The page cache contains buffer pages these days.. */ |
| free = atomic_read(&page_cache_size); |
| free += nr_free_pages(); |
| free += nr_swap_pages; |
| |
| /* |
| * This double-counts: the nrpages are both in the page-cache |
| * and in the swapper space. At the same time, this compensates |
| * for the swap-space over-allocation (ie "nr_swap_pages" being |
| * too small. |
| */ |
| free += swapper_space.nrpages; |
| |
| /* |
| * The code below doesn't account for free space in the inode |
| * and dentry slab cache, slab cache fragmentation, inodes and |
| * dentries which will become freeable under VM load, etc. |
| * Lets just hope all these (complex) factors balance out... |
| */ |
| free += (dentry_stat.nr_unused * sizeof(struct dentry)) >> PAGE_SHIFT; |
| free += (inodes_stat.nr_unused * sizeof(struct inode)) >> PAGE_SHIFT; |
| |
| return free > pages; |
| } |
| |
| /* Remove one vm structure from the inode's i_mapping address space. */ |
| static inline void __remove_shared_vm_struct(struct vm_area_struct *vma) |
| { |
| struct file * file = vma->vm_file; |
| |
| if (file) { |
| struct inode *inode = file->f_dentry->d_inode; |
| if (vma->vm_flags & VM_DENYWRITE) |
| atomic_inc(&inode->i_writecount); |
| if(vma->vm_next_share) |
| vma->vm_next_share->vm_pprev_share = vma->vm_pprev_share; |
| *vma->vm_pprev_share = vma->vm_next_share; |
| } |
| } |
| |
| static inline void remove_shared_vm_struct(struct vm_area_struct *vma) |
| { |
| lock_vma_mappings(vma); |
| __remove_shared_vm_struct(vma); |
| unlock_vma_mappings(vma); |
| } |
| |
| void lock_vma_mappings(struct vm_area_struct *vma) |
| { |
| struct address_space *mapping; |
| |
| mapping = NULL; |
| if (vma->vm_file) |
| mapping = vma->vm_file->f_dentry->d_inode->i_mapping; |
| if (mapping) |
| spin_lock(&mapping->i_shared_lock); |
| } |
| |
| void unlock_vma_mappings(struct vm_area_struct *vma) |
| { |
| struct address_space *mapping; |
| |
| mapping = NULL; |
| if (vma->vm_file) |
| mapping = vma->vm_file->f_dentry->d_inode->i_mapping; |
| if (mapping) |
| spin_unlock(&mapping->i_shared_lock); |
| } |
| |
| /* |
| * 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; |
| |
| /* Check if we have enough memory.. */ |
| if (!vm_enough_memory((newbrk-oldbrk) >> PAGE_SHIFT)) |
| 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; |
| } |
| |
| /* Combine the mmap "prot" and "flags" argument into one "vm_flags" used |
| * internally. Essentially, translate the "PROT_xxx" and "MAP_xxx" bits |
| * into "VM_xxx". |
| */ |
| static inline unsigned long calc_vm_flags(unsigned long prot, unsigned long flags) |
| { |
| #define _trans(x,bit1,bit2) \ |
| ((bit1==bit2)?(x&bit1):(x&bit1)?bit2:0) |
| |
| unsigned long prot_bits, flag_bits; |
| prot_bits = |
| _trans(prot, PROT_READ, VM_READ) | |
| _trans(prot, PROT_WRITE, VM_WRITE) | |
| _trans(prot, PROT_EXEC, VM_EXEC); |
| flag_bits = |
| _trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) | |
| _trans(flags, MAP_DENYWRITE, VM_DENYWRITE) | |
| _trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE); |
| return prot_bits | flag_bits; |
| #undef _trans |
| } |
| |
| #ifdef DEBUG_MM_RB |
| static int browse_rb(rb_node_t * rb_node) { |
| int i = 0; |
| if (rb_node) { |
| i++; |
| i += browse_rb(rb_node->rb_left); |
| i += browse_rb(rb_node->rb_right); |
| } |
| return i; |
| } |
| |
| static 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.rb_node); |
| 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, |
| rb_node_t *** rb_link, rb_node_t ** rb_parent) |
| { |
| struct vm_area_struct * vma; |
| rb_node_t ** __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, |
| rb_node_t * 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; |
| } |
| } |
| |
| static inline void __vma_link_rb(struct mm_struct * mm, struct vm_area_struct * vma, |
| rb_node_t ** rb_link, rb_node_t * 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 inode * inode = file->f_dentry->d_inode; |
| struct address_space *mapping = inode->i_mapping; |
| struct vm_area_struct **head; |
| |
| if (vma->vm_flags & VM_DENYWRITE) |
| atomic_dec(&inode->i_writecount); |
| |
| head = &mapping->i_mmap; |
| if (vma->vm_flags & VM_SHARED) |
| head = &mapping->i_mmap_shared; |
| |
| /* insert vma into inode's share list */ |
| if((vma->vm_next_share = *head) != NULL) |
| (*head)->vm_pprev_share = &vma->vm_next_share; |
| *head = vma; |
| vma->vm_pprev_share = head; |
| } |
| } |
| |
| static void __vma_link(struct mm_struct * mm, struct vm_area_struct * vma, struct vm_area_struct * prev, |
| rb_node_t ** rb_link, rb_node_t * rb_parent) |
| { |
| __vma_link_list(mm, vma, prev, rb_parent); |
| __vma_link_rb(mm, vma, rb_link, rb_parent); |
| __vma_link_file(vma); |
| } |
| |
| static inline void vma_link(struct mm_struct * mm, struct vm_area_struct * vma, struct vm_area_struct * prev, |
| rb_node_t ** rb_link, rb_node_t * rb_parent) |
| { |
| lock_vma_mappings(vma); |
| spin_lock(&mm->page_table_lock); |
| __vma_link(mm, vma, prev, rb_link, rb_parent); |
| spin_unlock(&mm->page_table_lock); |
| unlock_vma_mappings(vma); |
| |
| mm->map_count++; |
| validate_mm(mm); |
| } |
| |
| static int vma_merge(struct mm_struct * mm, struct vm_area_struct * prev, |
| rb_node_t * rb_parent, unsigned long addr, unsigned long end, unsigned long vm_flags) |
| { |
| spinlock_t * lock = &mm->page_table_lock; |
| if (!prev) { |
| prev = rb_entry(rb_parent, struct vm_area_struct, vm_rb); |
| goto merge_next; |
| } |
| if (prev->vm_end == addr && can_vma_merge(prev, vm_flags)) { |
| struct vm_area_struct * next; |
| |
| spin_lock(lock); |
| prev->vm_end = end; |
| next = prev->vm_next; |
| if (next && prev->vm_end == next->vm_start && can_vma_merge(next, vm_flags)) { |
| prev->vm_end = next->vm_end; |
| __vma_unlink(mm, next, prev); |
| spin_unlock(lock); |
| |
| mm->map_count--; |
| kmem_cache_free(vm_area_cachep, next); |
| return 1; |
| } |
| spin_unlock(lock); |
| return 1; |
| } |
| |
| prev = prev->vm_next; |
| if (prev) { |
| merge_next: |
| if (!can_vma_merge(prev, vm_flags)) |
| return 0; |
| if (end == prev->vm_start) { |
| spin_lock(lock); |
| prev->vm_start = addr; |
| spin_unlock(lock); |
| return 1; |
| } |
| } |
| |
| return 0; |
| } |
| |
| unsigned long do_mmap_pgoff(struct mm_struct *mm, struct file * file, |
| unsigned long addr, unsigned long len, |
| unsigned long prot, unsigned long flags, |
| unsigned long pgoff) |
| { |
| struct vm_area_struct * vma, * prev; |
| unsigned int vm_flags; |
| int correct_wcount = 0; |
| int error; |
| rb_node_t ** rb_link, * rb_parent; |
| |
| if (file && (!file->f_op || !file->f_op->mmap)) |
| return -ENODEV; |
| |
| if (!len) |
| return addr; |
| |
| len = PAGE_ALIGN(len); |
| |
| if (len > TASK_SIZE || len == 0) |
| return -EINVAL; |
| |
| /* offset overflow? */ |
| if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) |
| return -EINVAL; |
| |
| /* Too many mappings? */ |
| if (mm->map_count > 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_flags(prot,flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; |
| |
| /* 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; |
| } |
| |
| 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(file->f_dentry->d_inode) && (file->f_mode & FMODE_WRITE)) |
| return -EACCES; |
| |
| /* make sure there are no mandatory locks on the file. */ |
| if (locks_verify_locked(file->f_dentry->d_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 { |
| vm_flags |= VM_SHARED | VM_MAYSHARE; |
| switch (flags & MAP_TYPE) { |
| default: |
| return -EINVAL; |
| case MAP_PRIVATE: |
| vm_flags &= ~(VM_SHARED | VM_MAYSHARE); |
| /* fall through */ |
| case MAP_SHARED: |
| break; |
| } |
| } |
| |
| /* Clear old maps */ |
| 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; |
| |
| /* Private writable mapping? Check memory availability.. */ |
| if ((vm_flags & (VM_SHARED | VM_WRITE)) == VM_WRITE && |
| !(flags & MAP_NORESERVE) && |
| !vm_enough_memory(len >> PAGE_SHIFT)) |
| return -ENOMEM; |
| |
| /* Can we just expand an old anonymous mapping? */ |
| if (!file && !(vm_flags & VM_SHARED) && rb_parent) |
| if (vma_merge(mm, prev, rb_parent, addr, addr + len, vm_flags)) |
| 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) |
| return -ENOMEM; |
| |
| 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_ops = NULL; |
| vma->vm_pgoff = pgoff; |
| vma->vm_file = NULL; |
| vma->vm_private_data = NULL; |
| vma->vm_raend = 0; |
| |
| 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 (flags & MAP_SHARED) { |
| error = shmem_zero_setup(vma); |
| if (error) |
| goto free_vma; |
| } |
| |
| /* Can addr have changed?? |
| * |
| * Answer: Yes, several device drivers can do it in their |
| * f_op->mmap method. -DaveM |
| */ |
| if (addr != vma->vm_start) { |
| /* |
| * It is a bit too late to pretend changing the virtual |
| * area of the mapping, we just corrupted userspace |
| * in the do_munmap, so FIXME (not in 2.4 to avoid breaking |
| * the driver API). |
| */ |
| struct vm_area_struct * stale_vma; |
| /* Since addr changed, we rely on the mmap op to prevent |
| * collisions with existing vmas and just use find_vma_prepare |
| * to update the tree pointers. |
| */ |
| addr = vma->vm_start; |
| stale_vma = find_vma_prepare(mm, addr, &prev, |
| &rb_link, &rb_parent); |
| /* |
| * Make sure the lowlevel driver did its job right. |
| */ |
| if (unlikely(stale_vma && stale_vma->vm_start < vma->vm_end)) { |
| printk(KERN_ERR "buggy mmap operation: [<%p>]\n", |
| file ? file->f_op->mmap : NULL); |
| BUG(); |
| } |
| } |
| |
| vma_link(mm, vma, prev, rb_link, rb_parent); |
| if (correct_wcount) |
| atomic_inc(&file->f_dentry->d_inode->i_writecount); |
| |
| out: |
| mm->total_vm += len >> PAGE_SHIFT; |
| if (vm_flags & VM_LOCKED) { |
| mm->locked_vm += len >> PAGE_SHIFT; |
| make_pages_present(addr, addr + len); |
| } |
| return addr; |
| |
| unmap_and_free_vma: |
| if (correct_wcount) |
| atomic_inc(&file->f_dentry->d_inode->i_writecount); |
| vma->vm_file = NULL; |
| fput(file); |
| |
| /* Undo any partial mapping done by a device driver. */ |
| zap_page_range(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
| free_vma: |
| kmem_cache_free(vm_area_cachep, vma); |
| return error; |
| } |
| |
| /* 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 vm_area_struct *vma; |
| |
| if (len > TASK_SIZE) |
| return -ENOMEM; |
| |
| if (addr) { |
| addr = PAGE_ALIGN(addr); |
| vma = find_vma(current->mm, addr); |
| if (TASK_SIZE - len >= addr && |
| (!vma || addr + len <= vma->vm_start)) |
| return addr; |
| } |
| addr = PAGE_ALIGN(TASK_UNMAPPED_BASE); |
| |
| for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) { |
| /* At this point: (!vma || addr < vma->vm_end). */ |
| if (TASK_SIZE - len < addr) |
| return -ENOMEM; |
| if (!vma || addr + len <= vma->vm_start) |
| 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 |
| |
| unsigned long get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) |
| { |
| if (flags & MAP_FIXED) { |
| if (addr > TASK_SIZE - len) |
| return -ENOMEM; |
| if (addr & ~PAGE_MASK) |
| 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); |
| } |
| |
| /* 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)) { |
| rb_node_t * 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; |
| } |
| |
| /* 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) |
| { |
| if (mm) { |
| /* Go through the RB tree quickly. */ |
| struct vm_area_struct * vma; |
| rb_node_t * rb_node, * rb_last_right, * rb_prev; |
| |
| rb_node = mm->mm_rb.rb_node; |
| rb_last_right = rb_prev = NULL; |
| 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; |
| rb_prev = rb_last_right; |
| if (vma_tmp->vm_start <= addr) |
| break; |
| rb_node = rb_node->rb_left; |
| } else { |
| rb_last_right = rb_node; |
| rb_node = rb_node->rb_right; |
| } |
| } |
| if (vma) { |
| if (vma->vm_rb.rb_left) { |
| rb_prev = vma->vm_rb.rb_left; |
| while (rb_prev->rb_right) |
| rb_prev = rb_prev->rb_right; |
| } |
| *pprev = NULL; |
| if (rb_prev) |
| *pprev = rb_entry(rb_prev, struct vm_area_struct, vm_rb); |
| if ((rb_prev ? (*pprev)->vm_next : mm->mmap) != vma) |
| BUG(); |
| return vma; |
| } |
| } |
| *pprev = NULL; |
| return NULL; |
| } |
| |
| 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; |
| } |
| |
| /* 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. |
| * This function works out what part of an area is affected and |
| * adjusts the mapping information. Since the actual page |
| * manipulation is done in do_mmap(), none need be done here, |
| * though it would probably be more appropriate. |
| * |
| * By the time this function is called, the area struct has been |
| * removed from the process mapping list, so it needs to be |
| * reinserted if necessary. |
| * |
| * The 4 main cases are: |
| * Unmapping the whole area |
| * Unmapping from the start of the segment to a point in it |
| * Unmapping from an intermediate point to the end |
| * Unmapping between to intermediate points, making a hole. |
| * |
| * Case 4 involves the creation of 2 new areas, for each side of |
| * the hole. If possible, we reuse the existing area rather than |
| * allocate a new one, and the return indicates whether the old |
| * area was reused. |
| */ |
| static struct vm_area_struct * unmap_fixup(struct mm_struct *mm, |
| struct vm_area_struct *area, unsigned long addr, size_t len, |
| struct vm_area_struct *extra) |
| { |
| struct vm_area_struct *mpnt; |
| unsigned long end = addr + len; |
| |
| area->vm_mm->total_vm -= len >> PAGE_SHIFT; |
| if (area->vm_flags & VM_LOCKED) |
| area->vm_mm->locked_vm -= len >> PAGE_SHIFT; |
| |
| /* Unmapping the whole area. */ |
| if (addr == area->vm_start && end == area->vm_end) { |
| if (area->vm_ops && area->vm_ops->close) |
| area->vm_ops->close(area); |
| if (area->vm_file) |
| fput(area->vm_file); |
| kmem_cache_free(vm_area_cachep, area); |
| return extra; |
| } |
| |
| /* Work out to one of the ends. */ |
| if (end == area->vm_end) { |
| /* |
| * here area isn't visible to the semaphore-less readers |
| * so we don't need to update it under the spinlock. |
| */ |
| area->vm_end = addr; |
| lock_vma_mappings(area); |
| spin_lock(&mm->page_table_lock); |
| } else if (addr == area->vm_start) { |
| area->vm_pgoff += (end - area->vm_start) >> PAGE_SHIFT; |
| /* same locking considerations of the above case */ |
| area->vm_start = end; |
| lock_vma_mappings(area); |
| spin_lock(&mm->page_table_lock); |
| } else { |
| /* Unmapping a hole: area->vm_start < addr <= end < area->vm_end */ |
| /* Add end mapping -- leave beginning for below */ |
| mpnt = extra; |
| extra = NULL; |
| |
| mpnt->vm_mm = area->vm_mm; |
| mpnt->vm_start = end; |
| mpnt->vm_end = area->vm_end; |
| mpnt->vm_page_prot = area->vm_page_prot; |
| mpnt->vm_flags = area->vm_flags; |
| mpnt->vm_raend = 0; |
| mpnt->vm_ops = area->vm_ops; |
| mpnt->vm_pgoff = area->vm_pgoff + ((end - area->vm_start) >> PAGE_SHIFT); |
| mpnt->vm_file = area->vm_file; |
| mpnt->vm_private_data = area->vm_private_data; |
| if (mpnt->vm_file) |
| get_file(mpnt->vm_file); |
| if (mpnt->vm_ops && mpnt->vm_ops->open) |
| mpnt->vm_ops->open(mpnt); |
| area->vm_end = addr; /* Truncate area */ |
| |
| /* Because mpnt->vm_file == area->vm_file this locks |
| * things correctly. |
| */ |
| lock_vma_mappings(area); |
| spin_lock(&mm->page_table_lock); |
| __insert_vm_struct(mm, mpnt); |
| } |
| |
| __insert_vm_struct(mm, area); |
| spin_unlock(&mm->page_table_lock); |
| unlock_vma_mappings(area); |
| return extra; |
| } |
| |
| /* |
| * 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 mm_struct * mm, 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; |
| |
| 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) |
| 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); |
| end_index = pgd_index(last); |
| if (end_index > start_index) { |
| clear_page_tables(mm, start_index, end_index - start_index); |
| flush_tlb_pgtables(mm, first & PGDIR_MASK, last & PGDIR_MASK); |
| } |
| } |
| |
| /* 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 Fitzhardine <jeremy@sw.oz.au> |
| */ |
| int do_munmap(struct mm_struct *mm, unsigned long addr, size_t len) |
| { |
| struct vm_area_struct *mpnt, *prev, **npp, *free, *extra; |
| |
| if ((addr & ~PAGE_MASK) || addr > TASK_SIZE || len > TASK_SIZE-addr) |
| return -EINVAL; |
| |
| if ((len = PAGE_ALIGN(len)) == 0) |
| return -EINVAL; |
| |
| /* Check if this memory area is ok - put it on the temporary |
| * list if so.. The checks here are pretty simple -- |
| * every area affected in some way (by any overlap) is put |
| * on the list. If nothing is put on, nothing is affected. |
| */ |
| mpnt = find_vma_prev(mm, addr, &prev); |
| if (!mpnt) |
| return 0; |
| /* we have addr < mpnt->vm_end */ |
| |
| if (mpnt->vm_start >= addr+len) |
| return 0; |
| |
| /* If we'll make "hole", check the vm areas limit */ |
| if ((mpnt->vm_start < addr && mpnt->vm_end > addr+len) |
| && mm->map_count >= max_map_count) |
| return -ENOMEM; |
| |
| /* |
| * We may need one additional vma to fix up the mappings ... |
| * and this is the last chance for an easy error exit. |
| */ |
| extra = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
| if (!extra) |
| return -ENOMEM; |
| |
| npp = (prev ? &prev->vm_next : &mm->mmap); |
| free = NULL; |
| spin_lock(&mm->page_table_lock); |
| for ( ; mpnt && mpnt->vm_start < addr+len; mpnt = *npp) { |
| *npp = mpnt->vm_next; |
| mpnt->vm_next = free; |
| free = mpnt; |
| rb_erase(&mpnt->vm_rb, &mm->mm_rb); |
| } |
| mm->mmap_cache = NULL; /* Kill the cache. */ |
| spin_unlock(&mm->page_table_lock); |
| |
| /* Ok - we have the memory areas we should free on the 'free' list, |
| * so release them, and unmap the page range.. |
| * If the one of the segments is only being partially unmapped, |
| * it will put new vm_area_struct(s) into the address space. |
| * In that case we have to be careful with VM_DENYWRITE. |
| */ |
| while ((mpnt = free) != NULL) { |
| unsigned long st, end, size; |
| struct file *file = NULL; |
| |
| free = free->vm_next; |
| |
| st = addr < mpnt->vm_start ? mpnt->vm_start : addr; |
| end = addr+len; |
| end = end > mpnt->vm_end ? mpnt->vm_end : end; |
| size = end - st; |
| |
| if (mpnt->vm_flags & VM_DENYWRITE && |
| (st != mpnt->vm_start || end != mpnt->vm_end) && |
| (file = mpnt->vm_file) != NULL) { |
| atomic_dec(&file->f_dentry->d_inode->i_writecount); |
| } |
| remove_shared_vm_struct(mpnt); |
| mm->map_count--; |
| |
| if((mpnt->vm_file != NULL) && (mpnt->vm_file->f_op != NULL) && |
| (mpnt->vm_file->f_op->munmap != NULL)) |
| mpnt->vm_file->f_op->munmap(mpnt->vm_file, mpnt, st, |
| size); |
| |
| zap_page_range(mm, st, size); |
| |
| /* |
| * Fix the mapping, and free the old area if it wasn't reused. |
| */ |
| extra = unmap_fixup(mm, mpnt, st, size, extra); |
| if (file) |
| atomic_inc(&file->f_dentry->d_inode->i_writecount); |
| } |
| validate_mm(mm); |
| |
| /* Release the extra vma struct if it wasn't used */ |
| if (extra) |
| kmem_cache_free(vm_area_cachep, extra); |
| |
| free_pgtables(mm, prev, addr, addr+len); |
| |
| return 0; |
| } |
| |
| 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; |
| rb_node_t ** rb_link, * rb_parent; |
| |
| len = PAGE_ALIGN(len); |
| if (!len) |
| return addr; |
| |
| /* |
| * 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 > max_map_count) |
| return -ENOMEM; |
| |
| if (!vm_enough_memory(len >> PAGE_SHIFT)) |
| return -ENOMEM; |
| |
| flags = VM_DATA_DEFAULT_FLAGS | mm->def_flags; |
| |
| /* Can we just expand an old anonymous mapping? */ |
| if (rb_parent && vma_merge(mm, prev, rb_parent, addr, addr + len, flags)) |
| goto out; |
| |
| /* |
| * create a vma struct for an anonymous mapping |
| */ |
| vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL); |
| if (!vma) |
| return -ENOMEM; |
| |
| vma->vm_mm = mm; |
| vma->vm_start = addr; |
| vma->vm_end = addr + len; |
| vma->vm_flags = flags; |
| vma->vm_page_prot = protection_map[flags & 0x0f]; |
| vma->vm_ops = NULL; |
| vma->vm_pgoff = 0; |
| vma->vm_file = NULL; |
| vma->vm_private_data = NULL; |
| |
| 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; |
| } |
| |
| /* Build the RB tree corresponding to the VMA list. */ |
| void build_mmap_rb(struct mm_struct * mm) |
| { |
| struct vm_area_struct * vma; |
| rb_node_t ** rb_link, * rb_parent; |
| |
| mm->mm_rb = RB_ROOT; |
| rb_link = &mm->mm_rb.rb_node; |
| rb_parent = NULL; |
| for (vma = mm->mmap; vma; vma = vma->vm_next) { |
| __vma_link_rb(mm, vma, rb_link, rb_parent); |
| rb_parent = &vma->vm_rb; |
| rb_link = &rb_parent->rb_right; |
| } |
| } |
| |
| /* Release all mmaps. */ |
| void exit_mmap(struct mm_struct * mm) |
| { |
| struct vm_area_struct * mpnt; |
| |
| release_segments(mm); |
| spin_lock(&mm->page_table_lock); |
| mpnt = mm->mmap; |
| mm->mmap = mm->mmap_cache = NULL; |
| mm->mm_rb = RB_ROOT; |
| mm->rss = 0; |
| spin_unlock(&mm->page_table_lock); |
| mm->total_vm = 0; |
| mm->locked_vm = 0; |
| |
| flush_cache_mm(mm); |
| while (mpnt) { |
| struct vm_area_struct * next = mpnt->vm_next; |
| unsigned long start = mpnt->vm_start; |
| unsigned long end = mpnt->vm_end; |
| unsigned long size = end - start; |
| |
| if (mpnt->vm_ops) { |
| if (mpnt->vm_ops->close) |
| mpnt->vm_ops->close(mpnt); |
| } |
| mm->map_count--; |
| remove_shared_vm_struct(mpnt); |
| zap_page_range(mm, start, size); |
| if (mpnt->vm_file) |
| fput(mpnt->vm_file); |
| kmem_cache_free(vm_area_cachep, mpnt); |
| mpnt = next; |
| } |
| |
| /* This is just debugging */ |
| if (mm->map_count) |
| BUG(); |
| |
| clear_page_tables(mm, FIRST_USER_PGD_NR, USER_PTRS_PER_PGD); |
| |
| flush_tlb_mm(mm); |
| } |
| |
| /* Insert vm structure into process list sorted by address |
| * and into the inode's i_mmap ring. If vm_file is non-NULL |
| * then the i_shared_lock must be held here. |
| */ |
| void __insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) |
| { |
| struct vm_area_struct * __vma, * prev; |
| rb_node_t ** 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++; |
| validate_mm(mm); |
| } |
| |
| void insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) |
| { |
| struct vm_area_struct * __vma, * prev; |
| rb_node_t ** 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); |
| validate_mm(mm); |
| } |