Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/fremap.c |
| 3 | * |
| 4 | * Explicit pagetable population and nonlinear (random) mappings support. |
| 5 | * |
| 6 | * started by Ingo Molnar, Copyright (C) 2002, 2003 |
| 7 | */ |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 8 | #include <linux/export.h> |
Alexey Dobriyan | 4af3c9c | 2007-10-16 23:29:23 -0700 | [diff] [blame] | 9 | #include <linux/backing-dev.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/mm.h> |
| 11 | #include <linux/swap.h> |
| 12 | #include <linux/file.h> |
| 13 | #include <linux/mman.h> |
| 14 | #include <linux/pagemap.h> |
| 15 | #include <linux/swapops.h> |
| 16 | #include <linux/rmap.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/syscalls.h> |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 18 | #include <linux/mmu_notifier.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 19 | |
| 20 | #include <asm/mmu_context.h> |
| 21 | #include <asm/cacheflush.h> |
| 22 | #include <asm/tlbflush.h> |
| 23 | |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 24 | #include "internal.h" |
| 25 | |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 26 | static void zap_pte(struct mm_struct *mm, struct vm_area_struct *vma, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | unsigned long addr, pte_t *ptep) |
| 28 | { |
| 29 | pte_t pte = *ptep; |
| 30 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | if (pte_present(pte)) { |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 32 | struct page *page; |
| 33 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 34 | flush_cache_page(vma, addr, pte_pfn(pte)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | pte = ptep_clear_flush(vma, addr, ptep); |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 36 | page = vm_normal_page(vma, addr, pte); |
| 37 | if (page) { |
| 38 | if (pte_dirty(pte)) |
| 39 | set_page_dirty(page); |
Hugh Dickins | edc315f | 2009-01-06 14:40:11 -0800 | [diff] [blame] | 40 | page_remove_rmap(page); |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 41 | page_cache_release(page); |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 42 | update_hiwater_rss(mm); |
KAMEZAWA Hiroyuki | d559db0 | 2010-03-05 13:41:39 -0800 | [diff] [blame] | 43 | dec_mm_counter(mm, MM_FILEPAGES); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 44 | } |
| 45 | } else { |
| 46 | if (!pte_file(pte)) |
| 47 | free_swap_and_cache(pte_to_swp_entry(pte)); |
Zachary Amsden | 9888a1c | 2006-09-30 23:29:31 -0700 | [diff] [blame] | 48 | pte_clear_not_present_full(mm, addr, ptep, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | } |
| 50 | } |
| 51 | |
| 52 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | * Install a file pte to a given virtual memory address, release any |
| 54 | * previously existing mapping. |
| 55 | */ |
Nick Piggin | d0217ac | 2007-07-19 01:47:03 -0700 | [diff] [blame] | 56 | static int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 57 | unsigned long addr, unsigned long pgoff, pgprot_t prot) |
| 58 | { |
| 59 | int err = -ENOMEM; |
Cyrill Gorcunov | 41bb347 | 2013-08-13 16:00:51 -0700 | [diff] [blame] | 60 | pte_t *pte, ptfile; |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 61 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | |
Linus Torvalds | c9cfcdd | 2005-11-29 14:03:14 -0800 | [diff] [blame] | 63 | pte = get_locked_pte(mm, addr, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | if (!pte) |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 65 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 66 | |
Cyrill Gorcunov | 41bb347 | 2013-08-13 16:00:51 -0700 | [diff] [blame] | 67 | ptfile = pgoff_to_pte(pgoff); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | |
Cyrill Gorcunov | 41bb347 | 2013-08-13 16:00:51 -0700 | [diff] [blame] | 69 | if (!pte_none(*pte)) { |
| 70 | if (pte_present(*pte) && pte_soft_dirty(*pte)) |
| 71 | pte_file_mksoft_dirty(ptfile); |
| 72 | zap_pte(mm, vma, addr, pte); |
| 73 | } |
| 74 | |
| 75 | set_pte_at(mm, addr, pte, ptfile); |
Hugh Dickins | 668e0d8 | 2006-06-23 02:03:45 -0700 | [diff] [blame] | 76 | /* |
| 77 | * We don't need to run update_mmu_cache() here because the "file pte" |
| 78 | * being installed by install_file_pte() is not a real pte - it's a |
| 79 | * non-present entry (like a swap entry), noting what file offset should |
| 80 | * be mapped there when there's a fault (in a non-linear vma where |
| 81 | * that's not obvious). |
| 82 | */ |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 83 | pte_unmap_unlock(pte, ptl); |
| 84 | err = 0; |
| 85 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | return err; |
| 87 | } |
| 88 | |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 89 | int generic_file_remap_pages(struct vm_area_struct *vma, unsigned long addr, |
| 90 | unsigned long size, pgoff_t pgoff) |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 91 | { |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 92 | struct mm_struct *mm = vma->vm_mm; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 93 | int err; |
| 94 | |
| 95 | do { |
| 96 | err = install_file_pte(mm, vma, addr, pgoff, vma->vm_page_prot); |
| 97 | if (err) |
| 98 | return err; |
| 99 | |
| 100 | size -= PAGE_SIZE; |
| 101 | addr += PAGE_SIZE; |
| 102 | pgoff++; |
| 103 | } while (size); |
| 104 | |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 105 | return 0; |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 106 | } |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 107 | EXPORT_SYMBOL(generic_file_remap_pages); |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 108 | |
Randy Dunlap | 8d63494 | 2007-10-16 23:31:29 -0700 | [diff] [blame] | 109 | /** |
| 110 | * sys_remap_file_pages - remap arbitrary pages of an existing VM_SHARED vma |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | * @start: start of the remapped virtual memory range |
| 112 | * @size: size of the remapped virtual memory range |
Randy Dunlap | 8d63494 | 2007-10-16 23:31:29 -0700 | [diff] [blame] | 113 | * @prot: new protection bits of the range (see NOTE) |
| 114 | * @pgoff: to-be-mapped page of the backing store file |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | * @flags: 0 or MAP_NONBLOCKED - the later will cause no IO. |
| 116 | * |
Randy Dunlap | 8d63494 | 2007-10-16 23:31:29 -0700 | [diff] [blame] | 117 | * sys_remap_file_pages remaps arbitrary pages of an existing VM_SHARED vma |
| 118 | * (shared backing store file). |
| 119 | * |
| 120 | * This syscall works purely via pagetables, so it's the most efficient |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | * way to map the same (large) file into a given virtual window. Unlike |
| 122 | * mmap()/mremap() it does not create any new vmas. The new mappings are |
| 123 | * also safe across swapout. |
| 124 | * |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 125 | * NOTE: the @prot parameter right now is ignored (but must be zero), |
Randy Dunlap | 8d63494 | 2007-10-16 23:31:29 -0700 | [diff] [blame] | 126 | * and the vma's default protection is used. Arbitrary protections |
| 127 | * might be implemented in the future. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | */ |
Heiko Carstens | 6a6160a | 2009-01-14 14:14:15 +0100 | [diff] [blame] | 129 | SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, |
| 130 | unsigned long, prot, unsigned long, pgoff, unsigned long, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | { |
| 132 | struct mm_struct *mm = current->mm; |
| 133 | struct address_space *mapping; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | struct vm_area_struct *vma; |
| 135 | int err = -EINVAL; |
| 136 | int has_write_lock = 0; |
Michel Lespinasse | a2362d2 | 2013-03-14 16:50:02 -0700 | [diff] [blame] | 137 | vm_flags_t vm_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | |
Randy Dunlap | 8d63494 | 2007-10-16 23:31:29 -0700 | [diff] [blame] | 139 | if (prot) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 140 | return err; |
| 141 | /* |
| 142 | * Sanitize the syscall parameters: |
| 143 | */ |
| 144 | start = start & PAGE_MASK; |
| 145 | size = size & PAGE_MASK; |
| 146 | |
| 147 | /* Does the address range wrap, or is the span zero-sized? */ |
| 148 | if (start + size <= start) |
| 149 | return err; |
| 150 | |
Larry Woodman | 5ec1055 | 2010-09-24 12:04:48 -0400 | [diff] [blame] | 151 | /* Does pgoff wrap? */ |
| 152 | if (pgoff + (size >> PAGE_SHIFT) < pgoff) |
| 153 | return err; |
| 154 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | /* Can we represent this offset inside this architecture's pte's? */ |
| 156 | #if PTE_FILE_MAX_BITS < BITS_PER_LONG |
| 157 | if (pgoff + (size >> PAGE_SHIFT) >= (1UL << PTE_FILE_MAX_BITS)) |
| 158 | return err; |
| 159 | #endif |
| 160 | |
| 161 | /* We need down_write() to change vma->vm_flags. */ |
| 162 | down_read(&mm->mmap_sem); |
| 163 | retry: |
| 164 | vma = find_vma(mm, start); |
| 165 | |
| 166 | /* |
| 167 | * Make sure the vma is shared, that it supports prefaulting, |
| 168 | * and that the remapped range is valid and fully within |
Michel Lespinasse | 940e7da | 2013-02-22 16:32:36 -0800 | [diff] [blame] | 169 | * the single existing vma. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | */ |
Michel Lespinasse | a2362d2 | 2013-03-14 16:50:02 -0700 | [diff] [blame] | 171 | if (!vma || !(vma->vm_flags & VM_SHARED)) |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 172 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | |
Linus Torvalds | deb521c | 2012-10-19 13:37:57 -0700 | [diff] [blame] | 174 | if (!vma->vm_ops || !vma->vm_ops->remap_pages) |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 175 | goto out; |
| 176 | |
Linus Torvalds | e92b05d | 2010-09-24 14:13:57 -0700 | [diff] [blame] | 177 | if (start < vma->vm_start || start + size > vma->vm_end) |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 178 | goto out; |
| 179 | |
| 180 | /* Must set VM_NONLINEAR before any pages are populated. */ |
| 181 | if (!(vma->vm_flags & VM_NONLINEAR)) { |
Michel Lespinasse | 940e7da | 2013-02-22 16:32:36 -0800 | [diff] [blame] | 182 | /* |
| 183 | * vm_private_data is used as a swapout cursor |
| 184 | * in a VM_NONLINEAR vma. |
| 185 | */ |
| 186 | if (vma->vm_private_data) |
| 187 | goto out; |
| 188 | |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 189 | /* Don't need a nonlinear mapping, exit success */ |
| 190 | if (pgoff == linear_page_index(vma, start)) { |
| 191 | err = 0; |
| 192 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | } |
| 194 | |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 195 | if (!has_write_lock) { |
Michel Lespinasse | 940e7da | 2013-02-22 16:32:36 -0800 | [diff] [blame] | 196 | get_write_lock: |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 197 | up_read(&mm->mmap_sem); |
| 198 | down_write(&mm->mmap_sem); |
| 199 | has_write_lock = 1; |
| 200 | goto retry; |
| 201 | } |
| 202 | mapping = vma->vm_file->f_mapping; |
Miklos Szeredi | 3ee6daf | 2007-07-19 01:47:24 -0700 | [diff] [blame] | 203 | /* |
| 204 | * page_mkclean doesn't work on nonlinear vmas, so if |
| 205 | * dirty pages need to be accounted, emulate with linear |
| 206 | * vmas. |
| 207 | */ |
| 208 | if (mapping_cap_account_dirty(mapping)) { |
| 209 | unsigned long addr; |
Al Viro | cb0942b | 2012-08-27 14:48:26 -0400 | [diff] [blame] | 210 | struct file *file = get_file(vma->vm_file); |
Miklos Szeredi | 3ee6daf | 2007-07-19 01:47:24 -0700 | [diff] [blame] | 211 | |
Michel Lespinasse | 09a9f1d | 2013-03-28 16:26:23 -0700 | [diff] [blame] | 212 | addr = mmap_region(file, start, size, |
| 213 | vma->vm_flags, pgoff); |
Oleg Nesterov | 8a459e4 | 2008-02-04 22:27:18 -0800 | [diff] [blame] | 214 | fput(file); |
Miklos Szeredi | 3ee6daf | 2007-07-19 01:47:24 -0700 | [diff] [blame] | 215 | if (IS_ERR_VALUE(addr)) { |
| 216 | err = addr; |
| 217 | } else { |
| 218 | BUG_ON(addr != start); |
| 219 | err = 0; |
| 220 | } |
| 221 | goto out; |
| 222 | } |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 223 | mutex_lock(&mapping->i_mmap_mutex); |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 224 | flush_dcache_mmap_lock(mapping); |
| 225 | vma->vm_flags |= VM_NONLINEAR; |
Michel Lespinasse | 6b2dbba | 2012-10-08 16:31:25 -0700 | [diff] [blame] | 226 | vma_interval_tree_remove(vma, &mapping->i_mmap); |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 227 | vma_nonlinear_insert(vma, &mapping->i_mmap_nonlinear); |
| 228 | flush_dcache_mmap_unlock(mapping); |
Peter Zijlstra | 3d48ae4 | 2011-05-24 17:12:06 -0700 | [diff] [blame] | 229 | mutex_unlock(&mapping->i_mmap_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | } |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 231 | |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 232 | if (vma->vm_flags & VM_LOCKED) { |
| 233 | /* |
| 234 | * drop PG_Mlocked flag for over-mapped range |
| 235 | */ |
Michel Lespinasse | 940e7da | 2013-02-22 16:32:36 -0800 | [diff] [blame] | 236 | if (!has_write_lock) |
| 237 | goto get_write_lock; |
Michel Lespinasse | a1ea954 | 2013-02-22 16:32:38 -0800 | [diff] [blame] | 238 | vm_flags = vma->vm_flags; |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 239 | munlock_vma_pages_range(vma, start, start + size); |
Michel Lespinasse | a1ea954 | 2013-02-22 16:32:38 -0800 | [diff] [blame] | 240 | vma->vm_flags = vm_flags; |
Rik van Riel | ba470de | 2008-10-18 20:26:50 -0700 | [diff] [blame] | 241 | } |
| 242 | |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 243 | mmu_notifier_invalidate_range_start(mm, start, start + size); |
Konstantin Khlebnikov | 0b173bc | 2012-10-08 16:28:46 -0700 | [diff] [blame] | 244 | err = vma->vm_ops->remap_pages(vma, start, size, pgoff); |
Andrea Arcangeli | cddb8a5 | 2008-07-28 15:46:29 -0700 | [diff] [blame] | 245 | mmu_notifier_invalidate_range_end(mm, start, start + size); |
Nick Piggin | 54cb882 | 2007-07-19 01:46:59 -0700 | [diff] [blame] | 246 | |
| 247 | /* |
| 248 | * We can't clear VM_NONLINEAR because we'd have to do |
| 249 | * it after ->populate completes, and that would prevent |
| 250 | * downgrading the lock. (Locks can't be upgraded). |
| 251 | */ |
| 252 | |
| 253 | out: |
Andrew Morton | 6d7825b | 2013-03-13 14:59:43 -0700 | [diff] [blame] | 254 | if (vma) |
| 255 | vm_flags = vma->vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | if (likely(!has_write_lock)) |
| 257 | up_read(&mm->mmap_sem); |
| 258 | else |
| 259 | up_write(&mm->mmap_sem); |
Michel Lespinasse | a1ea954 | 2013-02-22 16:32:38 -0800 | [diff] [blame] | 260 | if (!err && ((vm_flags & VM_LOCKED) || !(flags & MAP_NONBLOCK))) |
| 261 | mm_populate(start, size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | |
| 263 | return err; |
| 264 | } |