Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/memory.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * demand-loading started 01.12.91 - seems it is high on the list of |
| 9 | * things wanted, and it should be easy to implement. - Linus |
| 10 | */ |
| 11 | |
| 12 | /* |
| 13 | * Ok, demand-loading was easy, shared pages a little bit tricker. Shared |
| 14 | * pages started 02.12.91, seems to work. - Linus. |
| 15 | * |
| 16 | * Tested sharing by executing about 30 /bin/sh: under the old kernel it |
| 17 | * would have taken more than the 6M I have free, but it worked well as |
| 18 | * far as I could see. |
| 19 | * |
| 20 | * Also corrected some "invalidate()"s - I wasn't doing enough of them. |
| 21 | */ |
| 22 | |
| 23 | /* |
| 24 | * Real VM (paging to/from disk) started 18.12.91. Much more work and |
| 25 | * thought has to go into this. Oh, well.. |
| 26 | * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. |
| 27 | * Found it. Everything seems to work now. |
| 28 | * 20.12.91 - Ok, making the swap-device changeable like the root. |
| 29 | */ |
| 30 | |
| 31 | /* |
| 32 | * 05.04.94 - Multi-page memory management added for v1.1. |
| 33 | * Idea by Alex Bligh (alex@cconcepts.co.uk) |
| 34 | * |
| 35 | * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG |
| 36 | * (Gerhard.Wichert@pdb.siemens.de) |
| 37 | * |
| 38 | * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) |
| 39 | */ |
| 40 | |
| 41 | #include <linux/kernel_stat.h> |
| 42 | #include <linux/mm.h> |
| 43 | #include <linux/hugetlb.h> |
| 44 | #include <linux/mman.h> |
| 45 | #include <linux/swap.h> |
| 46 | #include <linux/highmem.h> |
| 47 | #include <linux/pagemap.h> |
| 48 | #include <linux/rmap.h> |
| 49 | #include <linux/module.h> |
| 50 | #include <linux/init.h> |
| 51 | |
| 52 | #include <asm/pgalloc.h> |
| 53 | #include <asm/uaccess.h> |
| 54 | #include <asm/tlb.h> |
| 55 | #include <asm/tlbflush.h> |
| 56 | #include <asm/pgtable.h> |
| 57 | |
| 58 | #include <linux/swapops.h> |
| 59 | #include <linux/elf.h> |
| 60 | |
Andy Whitcroft | d41dee3 | 2005-06-23 00:07:54 -0700 | [diff] [blame] | 61 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
| 63 | unsigned long max_mapnr; |
| 64 | struct page *mem_map; |
| 65 | |
| 66 | EXPORT_SYMBOL(max_mapnr); |
| 67 | EXPORT_SYMBOL(mem_map); |
| 68 | #endif |
| 69 | |
| 70 | unsigned long num_physpages; |
| 71 | /* |
| 72 | * A number of key systems in x86 including ioremap() rely on the assumption |
| 73 | * that high_memory defines the upper bound on direct map memory, then end |
| 74 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and |
| 75 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL |
| 76 | * and ZONE_HIGHMEM. |
| 77 | */ |
| 78 | void * high_memory; |
| 79 | unsigned long vmalloc_earlyreserve; |
| 80 | |
| 81 | EXPORT_SYMBOL(num_physpages); |
| 82 | EXPORT_SYMBOL(high_memory); |
| 83 | EXPORT_SYMBOL(vmalloc_earlyreserve); |
| 84 | |
| 85 | /* |
| 86 | * If a p?d_bad entry is found while walking page tables, report |
| 87 | * the error, before resetting entry to p?d_none. Usually (but |
| 88 | * very seldom) called out from the p?d_none_or_clear_bad macros. |
| 89 | */ |
| 90 | |
| 91 | void pgd_clear_bad(pgd_t *pgd) |
| 92 | { |
| 93 | pgd_ERROR(*pgd); |
| 94 | pgd_clear(pgd); |
| 95 | } |
| 96 | |
| 97 | void pud_clear_bad(pud_t *pud) |
| 98 | { |
| 99 | pud_ERROR(*pud); |
| 100 | pud_clear(pud); |
| 101 | } |
| 102 | |
| 103 | void pmd_clear_bad(pmd_t *pmd) |
| 104 | { |
| 105 | pmd_ERROR(*pmd); |
| 106 | pmd_clear(pmd); |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | * Note: this doesn't free the actual pages themselves. That |
| 111 | * has been handled earlier when unmapping all the memory regions. |
| 112 | */ |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 113 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | { |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 115 | struct page *page = pmd_page(*pmd); |
| 116 | pmd_clear(pmd); |
| 117 | pte_free_tlb(tlb, page); |
| 118 | dec_page_state(nr_page_table_pages); |
| 119 | tlb->mm->nr_ptes--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 120 | } |
| 121 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 122 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
| 123 | unsigned long addr, unsigned long end, |
| 124 | unsigned long floor, unsigned long ceiling) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | { |
| 126 | pmd_t *pmd; |
| 127 | unsigned long next; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 128 | unsigned long start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 129 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 130 | start = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | pmd = pmd_offset(pud, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 132 | do { |
| 133 | next = pmd_addr_end(addr, end); |
| 134 | if (pmd_none_or_clear_bad(pmd)) |
| 135 | continue; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 136 | free_pte_range(tlb, pmd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | } while (pmd++, addr = next, addr != end); |
| 138 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 139 | start &= PUD_MASK; |
| 140 | if (start < floor) |
| 141 | return; |
| 142 | if (ceiling) { |
| 143 | ceiling &= PUD_MASK; |
| 144 | if (!ceiling) |
| 145 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | } |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 147 | if (end - 1 > ceiling - 1) |
| 148 | return; |
| 149 | |
| 150 | pmd = pmd_offset(pud, start); |
| 151 | pud_clear(pud); |
| 152 | pmd_free_tlb(tlb, pmd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 153 | } |
| 154 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 155 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
| 156 | unsigned long addr, unsigned long end, |
| 157 | unsigned long floor, unsigned long ceiling) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 158 | { |
| 159 | pud_t *pud; |
| 160 | unsigned long next; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 161 | unsigned long start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 162 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 163 | start = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 164 | pud = pud_offset(pgd, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | do { |
| 166 | next = pud_addr_end(addr, end); |
| 167 | if (pud_none_or_clear_bad(pud)) |
| 168 | continue; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 169 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | } while (pud++, addr = next, addr != end); |
| 171 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 172 | start &= PGDIR_MASK; |
| 173 | if (start < floor) |
| 174 | return; |
| 175 | if (ceiling) { |
| 176 | ceiling &= PGDIR_MASK; |
| 177 | if (!ceiling) |
| 178 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | } |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 180 | if (end - 1 > ceiling - 1) |
| 181 | return; |
| 182 | |
| 183 | pud = pud_offset(pgd, start); |
| 184 | pgd_clear(pgd); |
| 185 | pud_free_tlb(tlb, pud); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | } |
| 187 | |
| 188 | /* |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 189 | * This function frees user-level page tables of a process. |
| 190 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | * Must be called with pagetable lock held. |
| 192 | */ |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 193 | void free_pgd_range(struct mmu_gather **tlb, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 194 | unsigned long addr, unsigned long end, |
| 195 | unsigned long floor, unsigned long ceiling) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | { |
| 197 | pgd_t *pgd; |
| 198 | unsigned long next; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 199 | unsigned long start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 200 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 201 | /* |
| 202 | * The next few lines have given us lots of grief... |
| 203 | * |
| 204 | * Why are we testing PMD* at this top level? Because often |
| 205 | * there will be no work to do at all, and we'd prefer not to |
| 206 | * go all the way down to the bottom just to discover that. |
| 207 | * |
| 208 | * Why all these "- 1"s? Because 0 represents both the bottom |
| 209 | * of the address space and the top of it (using -1 for the |
| 210 | * top wouldn't help much: the masks would do the wrong thing). |
| 211 | * The rule is that addr 0 and floor 0 refer to the bottom of |
| 212 | * the address space, but end 0 and ceiling 0 refer to the top |
| 213 | * Comparisons need to use "end - 1" and "ceiling - 1" (though |
| 214 | * that end 0 case should be mythical). |
| 215 | * |
| 216 | * Wherever addr is brought up or ceiling brought down, we must |
| 217 | * be careful to reject "the opposite 0" before it confuses the |
| 218 | * subsequent tests. But what about where end is brought down |
| 219 | * by PMD_SIZE below? no, end can't go down to 0 there. |
| 220 | * |
| 221 | * Whereas we round start (addr) and ceiling down, by different |
| 222 | * masks at different levels, in order to test whether a table |
| 223 | * now has no other vmas using it, so can be freed, we don't |
| 224 | * bother to round floor or end up - the tests don't need that. |
| 225 | */ |
| 226 | |
| 227 | addr &= PMD_MASK; |
| 228 | if (addr < floor) { |
| 229 | addr += PMD_SIZE; |
| 230 | if (!addr) |
| 231 | return; |
| 232 | } |
| 233 | if (ceiling) { |
| 234 | ceiling &= PMD_MASK; |
| 235 | if (!ceiling) |
| 236 | return; |
| 237 | } |
| 238 | if (end - 1 > ceiling - 1) |
| 239 | end -= PMD_SIZE; |
| 240 | if (addr > end - 1) |
| 241 | return; |
| 242 | |
| 243 | start = addr; |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 244 | pgd = pgd_offset((*tlb)->mm, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | do { |
| 246 | next = pgd_addr_end(addr, end); |
| 247 | if (pgd_none_or_clear_bad(pgd)) |
| 248 | continue; |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 249 | free_pud_range(*tlb, pgd, addr, next, floor, ceiling); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | } while (pgd++, addr = next, addr != end); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 251 | |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 252 | if (!tlb_is_full_mm(*tlb)) |
| 253 | flush_tlb_pgtables((*tlb)->mm, start, end); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 254 | } |
| 255 | |
| 256 | void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 257 | unsigned long floor, unsigned long ceiling) |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 258 | { |
| 259 | while (vma) { |
| 260 | struct vm_area_struct *next = vma->vm_next; |
| 261 | unsigned long addr = vma->vm_start; |
| 262 | |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 263 | if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) { |
| 264 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 265 | floor, next? next->vm_start: ceiling); |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 266 | } else { |
| 267 | /* |
| 268 | * Optimization: gather nearby vmas into one call down |
| 269 | */ |
| 270 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE |
| 271 | && !is_hugepage_only_range(vma->vm_mm, next->vm_start, |
| 272 | HPAGE_SIZE)) { |
| 273 | vma = next; |
| 274 | next = vma->vm_next; |
| 275 | } |
| 276 | free_pgd_range(tlb, addr, vma->vm_end, |
| 277 | floor, next? next->vm_start: ceiling); |
| 278 | } |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 279 | vma = next; |
| 280 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | } |
| 282 | |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 283 | pte_t fastcall *pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, |
| 284 | unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 285 | { |
| 286 | if (!pmd_present(*pmd)) { |
| 287 | struct page *new; |
| 288 | |
| 289 | spin_unlock(&mm->page_table_lock); |
| 290 | new = pte_alloc_one(mm, address); |
| 291 | spin_lock(&mm->page_table_lock); |
| 292 | if (!new) |
| 293 | return NULL; |
| 294 | /* |
| 295 | * Because we dropped the lock, we should re-check the |
| 296 | * entry, as somebody else could have populated it.. |
| 297 | */ |
| 298 | if (pmd_present(*pmd)) { |
| 299 | pte_free(new); |
| 300 | goto out; |
| 301 | } |
| 302 | mm->nr_ptes++; |
| 303 | inc_page_state(nr_page_table_pages); |
| 304 | pmd_populate(mm, pmd, new); |
| 305 | } |
| 306 | out: |
| 307 | return pte_offset_map(pmd, address); |
| 308 | } |
| 309 | |
| 310 | pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
| 311 | { |
| 312 | if (!pmd_present(*pmd)) { |
| 313 | pte_t *new; |
| 314 | |
| 315 | spin_unlock(&mm->page_table_lock); |
| 316 | new = pte_alloc_one_kernel(mm, address); |
| 317 | spin_lock(&mm->page_table_lock); |
| 318 | if (!new) |
| 319 | return NULL; |
| 320 | |
| 321 | /* |
| 322 | * Because we dropped the lock, we should re-check the |
| 323 | * entry, as somebody else could have populated it.. |
| 324 | */ |
| 325 | if (pmd_present(*pmd)) { |
| 326 | pte_free_kernel(new); |
| 327 | goto out; |
| 328 | } |
| 329 | pmd_populate_kernel(mm, pmd, new); |
| 330 | } |
| 331 | out: |
| 332 | return pte_offset_kernel(pmd, address); |
| 333 | } |
| 334 | |
| 335 | /* |
| 336 | * copy one vm_area from one task to the other. Assumes the page tables |
| 337 | * already present in the new task to be cleared in the whole range |
| 338 | * covered by this vma. |
| 339 | * |
| 340 | * dst->page_table_lock is held on entry and exit, |
| 341 | * but may be dropped within p[mg]d_alloc() and pte_alloc_map(). |
| 342 | */ |
| 343 | |
| 344 | static inline void |
| 345 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 346 | pte_t *dst_pte, pte_t *src_pte, unsigned long vm_flags, |
| 347 | unsigned long addr) |
| 348 | { |
| 349 | pte_t pte = *src_pte; |
| 350 | struct page *page; |
| 351 | unsigned long pfn; |
| 352 | |
| 353 | /* pte contains position in swap or file, so copy. */ |
| 354 | if (unlikely(!pte_present(pte))) { |
| 355 | if (!pte_file(pte)) { |
| 356 | swap_duplicate(pte_to_swp_entry(pte)); |
| 357 | /* make sure dst_mm is on swapoff's mmlist. */ |
| 358 | if (unlikely(list_empty(&dst_mm->mmlist))) { |
| 359 | spin_lock(&mmlist_lock); |
| 360 | list_add(&dst_mm->mmlist, &src_mm->mmlist); |
| 361 | spin_unlock(&mmlist_lock); |
| 362 | } |
| 363 | } |
| 364 | set_pte_at(dst_mm, addr, dst_pte, pte); |
| 365 | return; |
| 366 | } |
| 367 | |
| 368 | pfn = pte_pfn(pte); |
| 369 | /* the pte points outside of valid memory, the |
| 370 | * mapping is assumed to be good, meaningful |
| 371 | * and not mapped via rmap - duplicate the |
| 372 | * mapping as is. |
| 373 | */ |
| 374 | page = NULL; |
| 375 | if (pfn_valid(pfn)) |
| 376 | page = pfn_to_page(pfn); |
| 377 | |
| 378 | if (!page || PageReserved(page)) { |
| 379 | set_pte_at(dst_mm, addr, dst_pte, pte); |
| 380 | return; |
| 381 | } |
| 382 | |
| 383 | /* |
| 384 | * If it's a COW mapping, write protect it both |
| 385 | * in the parent and the child |
| 386 | */ |
| 387 | if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) { |
| 388 | ptep_set_wrprotect(src_mm, addr, src_pte); |
| 389 | pte = *src_pte; |
| 390 | } |
| 391 | |
| 392 | /* |
| 393 | * If it's a shared mapping, mark it clean in |
| 394 | * the child |
| 395 | */ |
| 396 | if (vm_flags & VM_SHARED) |
| 397 | pte = pte_mkclean(pte); |
| 398 | pte = pte_mkold(pte); |
| 399 | get_page(page); |
| 400 | inc_mm_counter(dst_mm, rss); |
| 401 | if (PageAnon(page)) |
| 402 | inc_mm_counter(dst_mm, anon_rss); |
| 403 | set_pte_at(dst_mm, addr, dst_pte, pte); |
| 404 | page_dup_rmap(page); |
| 405 | } |
| 406 | |
| 407 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 408 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, |
| 409 | unsigned long addr, unsigned long end) |
| 410 | { |
| 411 | pte_t *src_pte, *dst_pte; |
| 412 | unsigned long vm_flags = vma->vm_flags; |
| 413 | int progress; |
| 414 | |
| 415 | again: |
| 416 | dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr); |
| 417 | if (!dst_pte) |
| 418 | return -ENOMEM; |
| 419 | src_pte = pte_offset_map_nested(src_pmd, addr); |
| 420 | |
| 421 | progress = 0; |
| 422 | spin_lock(&src_mm->page_table_lock); |
| 423 | do { |
| 424 | /* |
| 425 | * We are holding two locks at this point - either of them |
| 426 | * could generate latencies in another task on another CPU. |
| 427 | */ |
| 428 | if (progress >= 32 && (need_resched() || |
| 429 | need_lockbreak(&src_mm->page_table_lock) || |
| 430 | need_lockbreak(&dst_mm->page_table_lock))) |
| 431 | break; |
| 432 | if (pte_none(*src_pte)) { |
| 433 | progress++; |
| 434 | continue; |
| 435 | } |
| 436 | copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vm_flags, addr); |
| 437 | progress += 8; |
| 438 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); |
| 439 | spin_unlock(&src_mm->page_table_lock); |
| 440 | |
| 441 | pte_unmap_nested(src_pte - 1); |
| 442 | pte_unmap(dst_pte - 1); |
| 443 | cond_resched_lock(&dst_mm->page_table_lock); |
| 444 | if (addr != end) |
| 445 | goto again; |
| 446 | return 0; |
| 447 | } |
| 448 | |
| 449 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 450 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, |
| 451 | unsigned long addr, unsigned long end) |
| 452 | { |
| 453 | pmd_t *src_pmd, *dst_pmd; |
| 454 | unsigned long next; |
| 455 | |
| 456 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); |
| 457 | if (!dst_pmd) |
| 458 | return -ENOMEM; |
| 459 | src_pmd = pmd_offset(src_pud, addr); |
| 460 | do { |
| 461 | next = pmd_addr_end(addr, end); |
| 462 | if (pmd_none_or_clear_bad(src_pmd)) |
| 463 | continue; |
| 464 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, |
| 465 | vma, addr, next)) |
| 466 | return -ENOMEM; |
| 467 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); |
| 468 | return 0; |
| 469 | } |
| 470 | |
| 471 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 472 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, |
| 473 | unsigned long addr, unsigned long end) |
| 474 | { |
| 475 | pud_t *src_pud, *dst_pud; |
| 476 | unsigned long next; |
| 477 | |
| 478 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); |
| 479 | if (!dst_pud) |
| 480 | return -ENOMEM; |
| 481 | src_pud = pud_offset(src_pgd, addr); |
| 482 | do { |
| 483 | next = pud_addr_end(addr, end); |
| 484 | if (pud_none_or_clear_bad(src_pud)) |
| 485 | continue; |
| 486 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, |
| 487 | vma, addr, next)) |
| 488 | return -ENOMEM; |
| 489 | } while (dst_pud++, src_pud++, addr = next, addr != end); |
| 490 | return 0; |
| 491 | } |
| 492 | |
| 493 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 494 | struct vm_area_struct *vma) |
| 495 | { |
| 496 | pgd_t *src_pgd, *dst_pgd; |
| 497 | unsigned long next; |
| 498 | unsigned long addr = vma->vm_start; |
| 499 | unsigned long end = vma->vm_end; |
| 500 | |
Nick Piggin | d992895 | 2005-08-28 16:49:11 +1000 | [diff] [blame] | 501 | /* |
| 502 | * Don't copy ptes where a page fault will fill them correctly. |
| 503 | * Fork becomes much lighter when there are big shared or private |
| 504 | * readonly mappings. The tradeoff is that copy_page_range is more |
| 505 | * efficient than faulting. |
| 506 | */ |
| 507 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) { |
| 508 | if (!vma->anon_vma) |
| 509 | return 0; |
| 510 | } |
| 511 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | if (is_vm_hugetlb_page(vma)) |
| 513 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); |
| 514 | |
| 515 | dst_pgd = pgd_offset(dst_mm, addr); |
| 516 | src_pgd = pgd_offset(src_mm, addr); |
| 517 | do { |
| 518 | next = pgd_addr_end(addr, end); |
| 519 | if (pgd_none_or_clear_bad(src_pgd)) |
| 520 | continue; |
| 521 | if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
| 522 | vma, addr, next)) |
| 523 | return -ENOMEM; |
| 524 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
| 525 | return 0; |
| 526 | } |
| 527 | |
| 528 | static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, |
| 529 | unsigned long addr, unsigned long end, |
| 530 | struct zap_details *details) |
| 531 | { |
| 532 | pte_t *pte; |
| 533 | |
| 534 | pte = pte_offset_map(pmd, addr); |
| 535 | do { |
| 536 | pte_t ptent = *pte; |
| 537 | if (pte_none(ptent)) |
| 538 | continue; |
| 539 | if (pte_present(ptent)) { |
| 540 | struct page *page = NULL; |
| 541 | unsigned long pfn = pte_pfn(ptent); |
| 542 | if (pfn_valid(pfn)) { |
| 543 | page = pfn_to_page(pfn); |
| 544 | if (PageReserved(page)) |
| 545 | page = NULL; |
| 546 | } |
| 547 | if (unlikely(details) && page) { |
| 548 | /* |
| 549 | * unmap_shared_mapping_pages() wants to |
| 550 | * invalidate cache without truncating: |
| 551 | * unmap shared but keep private pages. |
| 552 | */ |
| 553 | if (details->check_mapping && |
| 554 | details->check_mapping != page->mapping) |
| 555 | continue; |
| 556 | /* |
| 557 | * Each page->index must be checked when |
| 558 | * invalidating or truncating nonlinear. |
| 559 | */ |
| 560 | if (details->nonlinear_vma && |
| 561 | (page->index < details->first_index || |
| 562 | page->index > details->last_index)) |
| 563 | continue; |
| 564 | } |
Zachary Amsden | a600388 | 2005-09-03 15:55:04 -0700 | [diff] [blame] | 565 | ptent = ptep_get_and_clear_full(tlb->mm, addr, pte, |
| 566 | tlb->fullmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 567 | tlb_remove_tlb_entry(tlb, pte, addr); |
| 568 | if (unlikely(!page)) |
| 569 | continue; |
| 570 | if (unlikely(details) && details->nonlinear_vma |
| 571 | && linear_page_index(details->nonlinear_vma, |
| 572 | addr) != page->index) |
| 573 | set_pte_at(tlb->mm, addr, pte, |
| 574 | pgoff_to_pte(page->index)); |
| 575 | if (pte_dirty(ptent)) |
| 576 | set_page_dirty(page); |
| 577 | if (PageAnon(page)) |
| 578 | dec_mm_counter(tlb->mm, anon_rss); |
| 579 | else if (pte_young(ptent)) |
| 580 | mark_page_accessed(page); |
| 581 | tlb->freed++; |
| 582 | page_remove_rmap(page); |
| 583 | tlb_remove_page(tlb, page); |
| 584 | continue; |
| 585 | } |
| 586 | /* |
| 587 | * If details->check_mapping, we leave swap entries; |
| 588 | * if details->nonlinear_vma, we leave file entries. |
| 589 | */ |
| 590 | if (unlikely(details)) |
| 591 | continue; |
| 592 | if (!pte_file(ptent)) |
| 593 | free_swap_and_cache(pte_to_swp_entry(ptent)); |
Zachary Amsden | a600388 | 2005-09-03 15:55:04 -0700 | [diff] [blame] | 594 | pte_clear_full(tlb->mm, addr, pte, tlb->fullmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | } while (pte++, addr += PAGE_SIZE, addr != end); |
| 596 | pte_unmap(pte - 1); |
| 597 | } |
| 598 | |
| 599 | static inline void zap_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
| 600 | unsigned long addr, unsigned long end, |
| 601 | struct zap_details *details) |
| 602 | { |
| 603 | pmd_t *pmd; |
| 604 | unsigned long next; |
| 605 | |
| 606 | pmd = pmd_offset(pud, addr); |
| 607 | do { |
| 608 | next = pmd_addr_end(addr, end); |
| 609 | if (pmd_none_or_clear_bad(pmd)) |
| 610 | continue; |
| 611 | zap_pte_range(tlb, pmd, addr, next, details); |
| 612 | } while (pmd++, addr = next, addr != end); |
| 613 | } |
| 614 | |
| 615 | static inline void zap_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
| 616 | unsigned long addr, unsigned long end, |
| 617 | struct zap_details *details) |
| 618 | { |
| 619 | pud_t *pud; |
| 620 | unsigned long next; |
| 621 | |
| 622 | pud = pud_offset(pgd, addr); |
| 623 | do { |
| 624 | next = pud_addr_end(addr, end); |
| 625 | if (pud_none_or_clear_bad(pud)) |
| 626 | continue; |
| 627 | zap_pmd_range(tlb, pud, addr, next, details); |
| 628 | } while (pud++, addr = next, addr != end); |
| 629 | } |
| 630 | |
| 631 | static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
| 632 | unsigned long addr, unsigned long end, |
| 633 | struct zap_details *details) |
| 634 | { |
| 635 | pgd_t *pgd; |
| 636 | unsigned long next; |
| 637 | |
| 638 | if (details && !details->check_mapping && !details->nonlinear_vma) |
| 639 | details = NULL; |
| 640 | |
| 641 | BUG_ON(addr >= end); |
| 642 | tlb_start_vma(tlb, vma); |
| 643 | pgd = pgd_offset(vma->vm_mm, addr); |
| 644 | do { |
| 645 | next = pgd_addr_end(addr, end); |
| 646 | if (pgd_none_or_clear_bad(pgd)) |
| 647 | continue; |
| 648 | zap_pud_range(tlb, pgd, addr, next, details); |
| 649 | } while (pgd++, addr = next, addr != end); |
| 650 | tlb_end_vma(tlb, vma); |
| 651 | } |
| 652 | |
| 653 | #ifdef CONFIG_PREEMPT |
| 654 | # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) |
| 655 | #else |
| 656 | /* No preempt: go for improved straight-line efficiency */ |
| 657 | # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) |
| 658 | #endif |
| 659 | |
| 660 | /** |
| 661 | * unmap_vmas - unmap a range of memory covered by a list of vma's |
| 662 | * @tlbp: address of the caller's struct mmu_gather |
| 663 | * @mm: the controlling mm_struct |
| 664 | * @vma: the starting vma |
| 665 | * @start_addr: virtual address at which to start unmapping |
| 666 | * @end_addr: virtual address at which to end unmapping |
| 667 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here |
| 668 | * @details: details of nonlinear truncation or shared cache invalidation |
| 669 | * |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 670 | * Returns the end address of the unmapping (restart addr if interrupted). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | * |
| 672 | * Unmap all pages in the vma list. Called under page_table_lock. |
| 673 | * |
| 674 | * We aim to not hold page_table_lock for too long (for scheduling latency |
| 675 | * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to |
| 676 | * return the ending mmu_gather to the caller. |
| 677 | * |
| 678 | * Only addresses between `start' and `end' will be unmapped. |
| 679 | * |
| 680 | * The VMA list must be sorted in ascending virtual address order. |
| 681 | * |
| 682 | * unmap_vmas() assumes that the caller will flush the whole unmapped address |
| 683 | * range after unmap_vmas() returns. So the only responsibility here is to |
| 684 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() |
| 685 | * drops the lock and schedules. |
| 686 | */ |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 687 | unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 688 | struct vm_area_struct *vma, unsigned long start_addr, |
| 689 | unsigned long end_addr, unsigned long *nr_accounted, |
| 690 | struct zap_details *details) |
| 691 | { |
| 692 | unsigned long zap_bytes = ZAP_BLOCK_SIZE; |
| 693 | unsigned long tlb_start = 0; /* For tlb_finish_mmu */ |
| 694 | int tlb_start_valid = 0; |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 695 | unsigned long start = start_addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 696 | spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; |
| 697 | int fullmm = tlb_is_full_mm(*tlbp); |
| 698 | |
| 699 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | unsigned long end; |
| 701 | |
| 702 | start = max(vma->vm_start, start_addr); |
| 703 | if (start >= vma->vm_end) |
| 704 | continue; |
| 705 | end = min(vma->vm_end, end_addr); |
| 706 | if (end <= vma->vm_start) |
| 707 | continue; |
| 708 | |
| 709 | if (vma->vm_flags & VM_ACCOUNT) |
| 710 | *nr_accounted += (end - start) >> PAGE_SHIFT; |
| 711 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 712 | while (start != end) { |
| 713 | unsigned long block; |
| 714 | |
| 715 | if (!tlb_start_valid) { |
| 716 | tlb_start = start; |
| 717 | tlb_start_valid = 1; |
| 718 | } |
| 719 | |
| 720 | if (is_vm_hugetlb_page(vma)) { |
| 721 | block = end - start; |
| 722 | unmap_hugepage_range(vma, start, end); |
| 723 | } else { |
| 724 | block = min(zap_bytes, end - start); |
| 725 | unmap_page_range(*tlbp, vma, start, |
| 726 | start + block, details); |
| 727 | } |
| 728 | |
| 729 | start += block; |
| 730 | zap_bytes -= block; |
| 731 | if ((long)zap_bytes > 0) |
| 732 | continue; |
| 733 | |
| 734 | tlb_finish_mmu(*tlbp, tlb_start, start); |
| 735 | |
| 736 | if (need_resched() || |
| 737 | need_lockbreak(&mm->page_table_lock) || |
| 738 | (i_mmap_lock && need_lockbreak(i_mmap_lock))) { |
| 739 | if (i_mmap_lock) { |
| 740 | /* must reset count of rss freed */ |
| 741 | *tlbp = tlb_gather_mmu(mm, fullmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | goto out; |
| 743 | } |
| 744 | spin_unlock(&mm->page_table_lock); |
| 745 | cond_resched(); |
| 746 | spin_lock(&mm->page_table_lock); |
| 747 | } |
| 748 | |
| 749 | *tlbp = tlb_gather_mmu(mm, fullmm); |
| 750 | tlb_start_valid = 0; |
| 751 | zap_bytes = ZAP_BLOCK_SIZE; |
| 752 | } |
| 753 | } |
| 754 | out: |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 755 | return start; /* which is now the end (or restart) address */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 756 | } |
| 757 | |
| 758 | /** |
| 759 | * zap_page_range - remove user pages in a given range |
| 760 | * @vma: vm_area_struct holding the applicable pages |
| 761 | * @address: starting address of pages to zap |
| 762 | * @size: number of bytes to zap |
| 763 | * @details: details of nonlinear truncation or shared cache invalidation |
| 764 | */ |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 765 | unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 766 | unsigned long size, struct zap_details *details) |
| 767 | { |
| 768 | struct mm_struct *mm = vma->vm_mm; |
| 769 | struct mmu_gather *tlb; |
| 770 | unsigned long end = address + size; |
| 771 | unsigned long nr_accounted = 0; |
| 772 | |
| 773 | if (is_vm_hugetlb_page(vma)) { |
| 774 | zap_hugepage_range(vma, address, size); |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 775 | return end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 776 | } |
| 777 | |
| 778 | lru_add_drain(); |
| 779 | spin_lock(&mm->page_table_lock); |
| 780 | tlb = tlb_gather_mmu(mm, 0); |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 781 | end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 782 | tlb_finish_mmu(tlb, address, end); |
| 783 | spin_unlock(&mm->page_table_lock); |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 784 | return end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 785 | } |
| 786 | |
| 787 | /* |
| 788 | * Do a quick page-table lookup for a single page. |
| 789 | * mm->page_table_lock must be held. |
| 790 | */ |
Andrew Morton | 1aaf18f | 2005-07-27 11:43:54 -0700 | [diff] [blame] | 791 | static struct page *__follow_page(struct mm_struct *mm, unsigned long address, |
| 792 | int read, int write, int accessed) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | { |
| 794 | pgd_t *pgd; |
| 795 | pud_t *pud; |
| 796 | pmd_t *pmd; |
| 797 | pte_t *ptep, pte; |
| 798 | unsigned long pfn; |
| 799 | struct page *page; |
| 800 | |
| 801 | page = follow_huge_addr(mm, address, write); |
| 802 | if (! IS_ERR(page)) |
| 803 | return page; |
| 804 | |
| 805 | pgd = pgd_offset(mm, address); |
| 806 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) |
| 807 | goto out; |
| 808 | |
| 809 | pud = pud_offset(pgd, address); |
| 810 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) |
| 811 | goto out; |
| 812 | |
| 813 | pmd = pmd_offset(pud, address); |
| 814 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) |
| 815 | goto out; |
| 816 | if (pmd_huge(*pmd)) |
| 817 | return follow_huge_pmd(mm, address, pmd, write); |
| 818 | |
| 819 | ptep = pte_offset_map(pmd, address); |
| 820 | if (!ptep) |
| 821 | goto out; |
| 822 | |
| 823 | pte = *ptep; |
| 824 | pte_unmap(ptep); |
| 825 | if (pte_present(pte)) { |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 826 | if (write && !pte_write(pte)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 827 | goto out; |
| 828 | if (read && !pte_read(pte)) |
| 829 | goto out; |
| 830 | pfn = pte_pfn(pte); |
| 831 | if (pfn_valid(pfn)) { |
| 832 | page = pfn_to_page(pfn); |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 833 | if (accessed) { |
| 834 | if (write && !pte_dirty(pte) &&!PageDirty(page)) |
| 835 | set_page_dirty(page); |
Andrew Morton | 1aaf18f | 2005-07-27 11:43:54 -0700 | [diff] [blame] | 836 | mark_page_accessed(page); |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 837 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 838 | return page; |
| 839 | } |
| 840 | } |
| 841 | |
| 842 | out: |
| 843 | return NULL; |
| 844 | } |
| 845 | |
Andrew Morton | 1aaf18f | 2005-07-27 11:43:54 -0700 | [diff] [blame] | 846 | inline struct page * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 847 | follow_page(struct mm_struct *mm, unsigned long address, int write) |
| 848 | { |
Andrew Morton | 1aaf18f | 2005-07-27 11:43:54 -0700 | [diff] [blame] | 849 | return __follow_page(mm, address, 0, write, 1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 850 | } |
| 851 | |
Andrew Morton | 1aaf18f | 2005-07-27 11:43:54 -0700 | [diff] [blame] | 852 | /* |
| 853 | * check_user_page_readable() can be called frm niterrupt context by oprofile, |
| 854 | * so we need to avoid taking any non-irq-safe locks |
| 855 | */ |
| 856 | int check_user_page_readable(struct mm_struct *mm, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 857 | { |
Andrew Morton | 1aaf18f | 2005-07-27 11:43:54 -0700 | [diff] [blame] | 858 | return __follow_page(mm, address, 1, 0, 0) != NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 859 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | EXPORT_SYMBOL(check_user_page_readable); |
| 861 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 862 | static inline int |
| 863 | untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma, |
| 864 | unsigned long address) |
| 865 | { |
| 866 | pgd_t *pgd; |
| 867 | pud_t *pud; |
| 868 | pmd_t *pmd; |
| 869 | |
| 870 | /* Check if the vma is for an anonymous mapping. */ |
| 871 | if (vma->vm_ops && vma->vm_ops->nopage) |
| 872 | return 0; |
| 873 | |
| 874 | /* Check if page directory entry exists. */ |
| 875 | pgd = pgd_offset(mm, address); |
| 876 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) |
| 877 | return 1; |
| 878 | |
| 879 | pud = pud_offset(pgd, address); |
| 880 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) |
| 881 | return 1; |
| 882 | |
| 883 | /* Check if page middle directory entry exists. */ |
| 884 | pmd = pmd_offset(pud, address); |
| 885 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) |
| 886 | return 1; |
| 887 | |
| 888 | /* There is a pte slot for 'address' in 'mm'. */ |
| 889 | return 0; |
| 890 | } |
| 891 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 892 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
| 893 | unsigned long start, int len, int write, int force, |
| 894 | struct page **pages, struct vm_area_struct **vmas) |
| 895 | { |
| 896 | int i; |
| 897 | unsigned int flags; |
| 898 | |
| 899 | /* |
| 900 | * Require read or write permissions. |
| 901 | * If 'force' is set, we only require the "MAY" flags. |
| 902 | */ |
| 903 | flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
| 904 | flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
| 905 | i = 0; |
| 906 | |
| 907 | do { |
| 908 | struct vm_area_struct * vma; |
| 909 | |
| 910 | vma = find_extend_vma(mm, start); |
| 911 | if (!vma && in_gate_area(tsk, start)) { |
| 912 | unsigned long pg = start & PAGE_MASK; |
| 913 | struct vm_area_struct *gate_vma = get_gate_vma(tsk); |
| 914 | pgd_t *pgd; |
| 915 | pud_t *pud; |
| 916 | pmd_t *pmd; |
| 917 | pte_t *pte; |
| 918 | if (write) /* user gate pages are read-only */ |
| 919 | return i ? : -EFAULT; |
| 920 | if (pg > TASK_SIZE) |
| 921 | pgd = pgd_offset_k(pg); |
| 922 | else |
| 923 | pgd = pgd_offset_gate(mm, pg); |
| 924 | BUG_ON(pgd_none(*pgd)); |
| 925 | pud = pud_offset(pgd, pg); |
| 926 | BUG_ON(pud_none(*pud)); |
| 927 | pmd = pmd_offset(pud, pg); |
Hugh Dickins | 690dbe1 | 2005-08-01 21:11:42 -0700 | [diff] [blame] | 928 | if (pmd_none(*pmd)) |
| 929 | return i ? : -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 930 | pte = pte_offset_map(pmd, pg); |
Hugh Dickins | 690dbe1 | 2005-08-01 21:11:42 -0700 | [diff] [blame] | 931 | if (pte_none(*pte)) { |
| 932 | pte_unmap(pte); |
| 933 | return i ? : -EFAULT; |
| 934 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 935 | if (pages) { |
| 936 | pages[i] = pte_page(*pte); |
| 937 | get_page(pages[i]); |
| 938 | } |
| 939 | pte_unmap(pte); |
| 940 | if (vmas) |
| 941 | vmas[i] = gate_vma; |
| 942 | i++; |
| 943 | start += PAGE_SIZE; |
| 944 | len--; |
| 945 | continue; |
| 946 | } |
| 947 | |
| 948 | if (!vma || (vma->vm_flags & VM_IO) |
| 949 | || !(flags & vma->vm_flags)) |
| 950 | return i ? : -EFAULT; |
| 951 | |
| 952 | if (is_vm_hugetlb_page(vma)) { |
| 953 | i = follow_hugetlb_page(mm, vma, pages, vmas, |
| 954 | &start, &len, i); |
| 955 | continue; |
| 956 | } |
| 957 | spin_lock(&mm->page_table_lock); |
| 958 | do { |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 959 | int write_access = write; |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 960 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 961 | |
| 962 | cond_resched_lock(&mm->page_table_lock); |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 963 | while (!(page = follow_page(mm, start, write_access))) { |
Linus Torvalds | a68d2eb | 2005-08-03 10:07:09 -0700 | [diff] [blame] | 964 | int ret; |
| 965 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 966 | /* |
| 967 | * Shortcut for anonymous pages. We don't want |
| 968 | * to force the creation of pages tables for |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 969 | * insanely big anonymously mapped areas that |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 970 | * nobody touched so far. This is important |
| 971 | * for doing a core dump for these mappings. |
| 972 | */ |
Linus Torvalds | 4ceb5db | 2005-08-01 11:14:49 -0700 | [diff] [blame] | 973 | if (!write && untouched_anonymous_page(mm,vma,start)) { |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 974 | page = ZERO_PAGE(start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | break; |
| 976 | } |
| 977 | spin_unlock(&mm->page_table_lock); |
Linus Torvalds | a68d2eb | 2005-08-03 10:07:09 -0700 | [diff] [blame] | 978 | ret = __handle_mm_fault(mm, vma, start, write_access); |
| 979 | |
| 980 | /* |
| 981 | * The VM_FAULT_WRITE bit tells us that do_wp_page has |
| 982 | * broken COW when necessary, even if maybe_mkwrite |
| 983 | * decided not to set pte_write. We can thus safely do |
| 984 | * subsequent page lookups as if they were reads. |
| 985 | */ |
| 986 | if (ret & VM_FAULT_WRITE) |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 987 | write_access = 0; |
Linus Torvalds | a68d2eb | 2005-08-03 10:07:09 -0700 | [diff] [blame] | 988 | |
| 989 | switch (ret & ~VM_FAULT_WRITE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 990 | case VM_FAULT_MINOR: |
| 991 | tsk->min_flt++; |
| 992 | break; |
| 993 | case VM_FAULT_MAJOR: |
| 994 | tsk->maj_flt++; |
| 995 | break; |
| 996 | case VM_FAULT_SIGBUS: |
| 997 | return i ? i : -EFAULT; |
| 998 | case VM_FAULT_OOM: |
| 999 | return i ? i : -ENOMEM; |
| 1000 | default: |
| 1001 | BUG(); |
| 1002 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1003 | spin_lock(&mm->page_table_lock); |
| 1004 | } |
| 1005 | if (pages) { |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1006 | pages[i] = page; |
| 1007 | flush_dcache_page(page); |
| 1008 | if (!PageReserved(page)) |
| 1009 | page_cache_get(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1010 | } |
| 1011 | if (vmas) |
| 1012 | vmas[i] = vma; |
| 1013 | i++; |
| 1014 | start += PAGE_SIZE; |
| 1015 | len--; |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1016 | } while (len && start < vma->vm_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1017 | spin_unlock(&mm->page_table_lock); |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1018 | } while (len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1019 | return i; |
| 1020 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1021 | EXPORT_SYMBOL(get_user_pages); |
| 1022 | |
| 1023 | static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, |
| 1024 | unsigned long addr, unsigned long end, pgprot_t prot) |
| 1025 | { |
| 1026 | pte_t *pte; |
| 1027 | |
| 1028 | pte = pte_alloc_map(mm, pmd, addr); |
| 1029 | if (!pte) |
| 1030 | return -ENOMEM; |
| 1031 | do { |
| 1032 | pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(addr), prot)); |
| 1033 | BUG_ON(!pte_none(*pte)); |
| 1034 | set_pte_at(mm, addr, pte, zero_pte); |
| 1035 | } while (pte++, addr += PAGE_SIZE, addr != end); |
| 1036 | pte_unmap(pte - 1); |
| 1037 | return 0; |
| 1038 | } |
| 1039 | |
| 1040 | static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, |
| 1041 | unsigned long addr, unsigned long end, pgprot_t prot) |
| 1042 | { |
| 1043 | pmd_t *pmd; |
| 1044 | unsigned long next; |
| 1045 | |
| 1046 | pmd = pmd_alloc(mm, pud, addr); |
| 1047 | if (!pmd) |
| 1048 | return -ENOMEM; |
| 1049 | do { |
| 1050 | next = pmd_addr_end(addr, end); |
| 1051 | if (zeromap_pte_range(mm, pmd, addr, next, prot)) |
| 1052 | return -ENOMEM; |
| 1053 | } while (pmd++, addr = next, addr != end); |
| 1054 | return 0; |
| 1055 | } |
| 1056 | |
| 1057 | static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, |
| 1058 | unsigned long addr, unsigned long end, pgprot_t prot) |
| 1059 | { |
| 1060 | pud_t *pud; |
| 1061 | unsigned long next; |
| 1062 | |
| 1063 | pud = pud_alloc(mm, pgd, addr); |
| 1064 | if (!pud) |
| 1065 | return -ENOMEM; |
| 1066 | do { |
| 1067 | next = pud_addr_end(addr, end); |
| 1068 | if (zeromap_pmd_range(mm, pud, addr, next, prot)) |
| 1069 | return -ENOMEM; |
| 1070 | } while (pud++, addr = next, addr != end); |
| 1071 | return 0; |
| 1072 | } |
| 1073 | |
| 1074 | int zeromap_page_range(struct vm_area_struct *vma, |
| 1075 | unsigned long addr, unsigned long size, pgprot_t prot) |
| 1076 | { |
| 1077 | pgd_t *pgd; |
| 1078 | unsigned long next; |
| 1079 | unsigned long end = addr + size; |
| 1080 | struct mm_struct *mm = vma->vm_mm; |
| 1081 | int err; |
| 1082 | |
| 1083 | BUG_ON(addr >= end); |
| 1084 | pgd = pgd_offset(mm, addr); |
| 1085 | flush_cache_range(vma, addr, end); |
| 1086 | spin_lock(&mm->page_table_lock); |
| 1087 | do { |
| 1088 | next = pgd_addr_end(addr, end); |
| 1089 | err = zeromap_pud_range(mm, pgd, addr, next, prot); |
| 1090 | if (err) |
| 1091 | break; |
| 1092 | } while (pgd++, addr = next, addr != end); |
| 1093 | spin_unlock(&mm->page_table_lock); |
| 1094 | return err; |
| 1095 | } |
| 1096 | |
| 1097 | /* |
| 1098 | * maps a range of physical memory into the requested pages. the old |
| 1099 | * mappings are removed. any references to nonexistent pages results |
| 1100 | * in null mappings (currently treated as "copy-on-access") |
| 1101 | */ |
| 1102 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, |
| 1103 | unsigned long addr, unsigned long end, |
| 1104 | unsigned long pfn, pgprot_t prot) |
| 1105 | { |
| 1106 | pte_t *pte; |
| 1107 | |
| 1108 | pte = pte_alloc_map(mm, pmd, addr); |
| 1109 | if (!pte) |
| 1110 | return -ENOMEM; |
| 1111 | do { |
| 1112 | BUG_ON(!pte_none(*pte)); |
| 1113 | if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn))) |
| 1114 | set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); |
| 1115 | pfn++; |
| 1116 | } while (pte++, addr += PAGE_SIZE, addr != end); |
| 1117 | pte_unmap(pte - 1); |
| 1118 | return 0; |
| 1119 | } |
| 1120 | |
| 1121 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, |
| 1122 | unsigned long addr, unsigned long end, |
| 1123 | unsigned long pfn, pgprot_t prot) |
| 1124 | { |
| 1125 | pmd_t *pmd; |
| 1126 | unsigned long next; |
| 1127 | |
| 1128 | pfn -= addr >> PAGE_SHIFT; |
| 1129 | pmd = pmd_alloc(mm, pud, addr); |
| 1130 | if (!pmd) |
| 1131 | return -ENOMEM; |
| 1132 | do { |
| 1133 | next = pmd_addr_end(addr, end); |
| 1134 | if (remap_pte_range(mm, pmd, addr, next, |
| 1135 | pfn + (addr >> PAGE_SHIFT), prot)) |
| 1136 | return -ENOMEM; |
| 1137 | } while (pmd++, addr = next, addr != end); |
| 1138 | return 0; |
| 1139 | } |
| 1140 | |
| 1141 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, |
| 1142 | unsigned long addr, unsigned long end, |
| 1143 | unsigned long pfn, pgprot_t prot) |
| 1144 | { |
| 1145 | pud_t *pud; |
| 1146 | unsigned long next; |
| 1147 | |
| 1148 | pfn -= addr >> PAGE_SHIFT; |
| 1149 | pud = pud_alloc(mm, pgd, addr); |
| 1150 | if (!pud) |
| 1151 | return -ENOMEM; |
| 1152 | do { |
| 1153 | next = pud_addr_end(addr, end); |
| 1154 | if (remap_pmd_range(mm, pud, addr, next, |
| 1155 | pfn + (addr >> PAGE_SHIFT), prot)) |
| 1156 | return -ENOMEM; |
| 1157 | } while (pud++, addr = next, addr != end); |
| 1158 | return 0; |
| 1159 | } |
| 1160 | |
| 1161 | /* Note: this is only safe if the mm semaphore is held when called. */ |
| 1162 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
| 1163 | unsigned long pfn, unsigned long size, pgprot_t prot) |
| 1164 | { |
| 1165 | pgd_t *pgd; |
| 1166 | unsigned long next; |
Hugh Dickins | 2d15cab | 2005-06-25 14:54:33 -0700 | [diff] [blame] | 1167 | unsigned long end = addr + PAGE_ALIGN(size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1168 | struct mm_struct *mm = vma->vm_mm; |
| 1169 | int err; |
| 1170 | |
| 1171 | /* |
| 1172 | * Physically remapped pages are special. Tell the |
| 1173 | * rest of the world about it: |
| 1174 | * VM_IO tells people not to look at these pages |
| 1175 | * (accesses can have side effects). |
| 1176 | * VM_RESERVED tells swapout not to try to touch |
| 1177 | * this region. |
| 1178 | */ |
| 1179 | vma->vm_flags |= VM_IO | VM_RESERVED; |
| 1180 | |
| 1181 | BUG_ON(addr >= end); |
| 1182 | pfn -= addr >> PAGE_SHIFT; |
| 1183 | pgd = pgd_offset(mm, addr); |
| 1184 | flush_cache_range(vma, addr, end); |
| 1185 | spin_lock(&mm->page_table_lock); |
| 1186 | do { |
| 1187 | next = pgd_addr_end(addr, end); |
| 1188 | err = remap_pud_range(mm, pgd, addr, next, |
| 1189 | pfn + (addr >> PAGE_SHIFT), prot); |
| 1190 | if (err) |
| 1191 | break; |
| 1192 | } while (pgd++, addr = next, addr != end); |
| 1193 | spin_unlock(&mm->page_table_lock); |
| 1194 | return err; |
| 1195 | } |
| 1196 | EXPORT_SYMBOL(remap_pfn_range); |
| 1197 | |
| 1198 | /* |
| 1199 | * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when |
| 1200 | * servicing faults for write access. In the normal case, do always want |
| 1201 | * pte_mkwrite. But get_user_pages can cause write faults for mappings |
| 1202 | * that do not have writing enabled, when used by access_process_vm. |
| 1203 | */ |
| 1204 | static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) |
| 1205 | { |
| 1206 | if (likely(vma->vm_flags & VM_WRITE)) |
| 1207 | pte = pte_mkwrite(pte); |
| 1208 | return pte; |
| 1209 | } |
| 1210 | |
| 1211 | /* |
| 1212 | * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock |
| 1213 | */ |
| 1214 | static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address, |
| 1215 | pte_t *page_table) |
| 1216 | { |
| 1217 | pte_t entry; |
| 1218 | |
| 1219 | entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)), |
| 1220 | vma); |
| 1221 | ptep_establish(vma, address, page_table, entry); |
| 1222 | update_mmu_cache(vma, address, entry); |
| 1223 | lazy_mmu_prot_update(entry); |
| 1224 | } |
| 1225 | |
| 1226 | /* |
| 1227 | * This routine handles present pages, when users try to write |
| 1228 | * to a shared page. It is done by copying the page to a new address |
| 1229 | * and decrementing the shared-page counter for the old page. |
| 1230 | * |
| 1231 | * Goto-purists beware: the only reason for goto's here is that it results |
| 1232 | * in better assembly code.. The "default" path will see no jumps at all. |
| 1233 | * |
| 1234 | * Note that this routine assumes that the protection checks have been |
| 1235 | * done by the caller (the low-level page fault routine in most cases). |
| 1236 | * Thus we can safely just mark it writable once we've done any necessary |
| 1237 | * COW. |
| 1238 | * |
| 1239 | * We also mark the page dirty at this point even though the page will |
| 1240 | * change only once the write actually happens. This avoids a few races, |
| 1241 | * and potentially makes it more efficient. |
| 1242 | * |
| 1243 | * We hold the mm semaphore and the page_table_lock on entry and exit |
| 1244 | * with the page_table_lock released. |
| 1245 | */ |
| 1246 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma, |
| 1247 | unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte) |
| 1248 | { |
| 1249 | struct page *old_page, *new_page; |
| 1250 | unsigned long pfn = pte_pfn(pte); |
| 1251 | pte_t entry; |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1252 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | |
| 1254 | if (unlikely(!pfn_valid(pfn))) { |
| 1255 | /* |
| 1256 | * This should really halt the system so it can be debugged or |
| 1257 | * at least the kernel stops what it's doing before it corrupts |
| 1258 | * data, but for the moment just pretend this is OOM. |
| 1259 | */ |
| 1260 | pte_unmap(page_table); |
| 1261 | printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n", |
| 1262 | address); |
| 1263 | spin_unlock(&mm->page_table_lock); |
| 1264 | return VM_FAULT_OOM; |
| 1265 | } |
| 1266 | old_page = pfn_to_page(pfn); |
| 1267 | |
Hugh Dickins | d296e9c | 2005-06-21 17:15:11 -0700 | [diff] [blame] | 1268 | if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1269 | int reuse = can_share_swap_page(old_page); |
| 1270 | unlock_page(old_page); |
| 1271 | if (reuse) { |
| 1272 | flush_cache_page(vma, address, pfn); |
| 1273 | entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)), |
| 1274 | vma); |
| 1275 | ptep_set_access_flags(vma, address, page_table, entry, 1); |
| 1276 | update_mmu_cache(vma, address, entry); |
| 1277 | lazy_mmu_prot_update(entry); |
| 1278 | pte_unmap(page_table); |
| 1279 | spin_unlock(&mm->page_table_lock); |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1280 | return VM_FAULT_MINOR|VM_FAULT_WRITE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1281 | } |
| 1282 | } |
| 1283 | pte_unmap(page_table); |
| 1284 | |
| 1285 | /* |
| 1286 | * Ok, we need to copy. Oh, well.. |
| 1287 | */ |
| 1288 | if (!PageReserved(old_page)) |
| 1289 | page_cache_get(old_page); |
| 1290 | spin_unlock(&mm->page_table_lock); |
| 1291 | |
| 1292 | if (unlikely(anon_vma_prepare(vma))) |
| 1293 | goto no_new_page; |
| 1294 | if (old_page == ZERO_PAGE(address)) { |
| 1295 | new_page = alloc_zeroed_user_highpage(vma, address); |
| 1296 | if (!new_page) |
| 1297 | goto no_new_page; |
| 1298 | } else { |
| 1299 | new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); |
| 1300 | if (!new_page) |
| 1301 | goto no_new_page; |
| 1302 | copy_user_highpage(new_page, old_page, address); |
| 1303 | } |
| 1304 | /* |
| 1305 | * Re-check the pte - we dropped the lock |
| 1306 | */ |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1307 | ret = VM_FAULT_MINOR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1308 | spin_lock(&mm->page_table_lock); |
| 1309 | page_table = pte_offset_map(pmd, address); |
| 1310 | if (likely(pte_same(*page_table, pte))) { |
| 1311 | if (PageAnon(old_page)) |
| 1312 | dec_mm_counter(mm, anon_rss); |
| 1313 | if (PageReserved(old_page)) |
| 1314 | inc_mm_counter(mm, rss); |
| 1315 | else |
| 1316 | page_remove_rmap(old_page); |
| 1317 | flush_cache_page(vma, address, pfn); |
| 1318 | break_cow(vma, new_page, address, page_table); |
| 1319 | lru_cache_add_active(new_page); |
| 1320 | page_add_anon_rmap(new_page, vma, address); |
| 1321 | |
| 1322 | /* Free the old page.. */ |
| 1323 | new_page = old_page; |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1324 | ret |= VM_FAULT_WRITE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1325 | } |
| 1326 | pte_unmap(page_table); |
| 1327 | page_cache_release(new_page); |
| 1328 | page_cache_release(old_page); |
| 1329 | spin_unlock(&mm->page_table_lock); |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1330 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1331 | |
| 1332 | no_new_page: |
| 1333 | page_cache_release(old_page); |
| 1334 | return VM_FAULT_OOM; |
| 1335 | } |
| 1336 | |
| 1337 | /* |
| 1338 | * Helper functions for unmap_mapping_range(). |
| 1339 | * |
| 1340 | * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ |
| 1341 | * |
| 1342 | * We have to restart searching the prio_tree whenever we drop the lock, |
| 1343 | * since the iterator is only valid while the lock is held, and anyway |
| 1344 | * a later vma might be split and reinserted earlier while lock dropped. |
| 1345 | * |
| 1346 | * The list of nonlinear vmas could be handled more efficiently, using |
| 1347 | * a placeholder, but handle it in the same way until a need is shown. |
| 1348 | * It is important to search the prio_tree before nonlinear list: a vma |
| 1349 | * may become nonlinear and be shifted from prio_tree to nonlinear list |
| 1350 | * while the lock is dropped; but never shifted from list to prio_tree. |
| 1351 | * |
| 1352 | * In order to make forward progress despite restarting the search, |
| 1353 | * vm_truncate_count is used to mark a vma as now dealt with, so we can |
| 1354 | * quickly skip it next time around. Since the prio_tree search only |
| 1355 | * shows us those vmas affected by unmapping the range in question, we |
| 1356 | * can't efficiently keep all vmas in step with mapping->truncate_count: |
| 1357 | * so instead reset them all whenever it wraps back to 0 (then go to 1). |
| 1358 | * mapping->truncate_count and vma->vm_truncate_count are protected by |
| 1359 | * i_mmap_lock. |
| 1360 | * |
| 1361 | * In order to make forward progress despite repeatedly restarting some |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1362 | * large vma, note the restart_addr from unmap_vmas when it breaks out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | * and restart from that address when we reach that vma again. It might |
| 1364 | * have been split or merged, shrunk or extended, but never shifted: so |
| 1365 | * restart_addr remains valid so long as it remains in the vma's range. |
| 1366 | * unmap_mapping_range forces truncate_count to leap over page-aligned |
| 1367 | * values so we can save vma's restart_addr in its truncate_count field. |
| 1368 | */ |
| 1369 | #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) |
| 1370 | |
| 1371 | static void reset_vma_truncate_counts(struct address_space *mapping) |
| 1372 | { |
| 1373 | struct vm_area_struct *vma; |
| 1374 | struct prio_tree_iter iter; |
| 1375 | |
| 1376 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) |
| 1377 | vma->vm_truncate_count = 0; |
| 1378 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) |
| 1379 | vma->vm_truncate_count = 0; |
| 1380 | } |
| 1381 | |
| 1382 | static int unmap_mapping_range_vma(struct vm_area_struct *vma, |
| 1383 | unsigned long start_addr, unsigned long end_addr, |
| 1384 | struct zap_details *details) |
| 1385 | { |
| 1386 | unsigned long restart_addr; |
| 1387 | int need_break; |
| 1388 | |
| 1389 | again: |
| 1390 | restart_addr = vma->vm_truncate_count; |
| 1391 | if (is_restart_addr(restart_addr) && start_addr < restart_addr) { |
| 1392 | start_addr = restart_addr; |
| 1393 | if (start_addr >= end_addr) { |
| 1394 | /* Top of vma has been split off since last time */ |
| 1395 | vma->vm_truncate_count = details->truncate_count; |
| 1396 | return 0; |
| 1397 | } |
| 1398 | } |
| 1399 | |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1400 | restart_addr = zap_page_range(vma, start_addr, |
| 1401 | end_addr - start_addr, details); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1402 | |
| 1403 | /* |
| 1404 | * We cannot rely on the break test in unmap_vmas: |
| 1405 | * on the one hand, we don't want to restart our loop |
| 1406 | * just because that broke out for the page_table_lock; |
| 1407 | * on the other hand, it does no test when vma is small. |
| 1408 | */ |
| 1409 | need_break = need_resched() || |
| 1410 | need_lockbreak(details->i_mmap_lock); |
| 1411 | |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1412 | if (restart_addr >= end_addr) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1413 | /* We have now completed this vma: mark it so */ |
| 1414 | vma->vm_truncate_count = details->truncate_count; |
| 1415 | if (!need_break) |
| 1416 | return 0; |
| 1417 | } else { |
| 1418 | /* Note restart_addr in vma's truncate_count field */ |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1419 | vma->vm_truncate_count = restart_addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1420 | if (!need_break) |
| 1421 | goto again; |
| 1422 | } |
| 1423 | |
| 1424 | spin_unlock(details->i_mmap_lock); |
| 1425 | cond_resched(); |
| 1426 | spin_lock(details->i_mmap_lock); |
| 1427 | return -EINTR; |
| 1428 | } |
| 1429 | |
| 1430 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, |
| 1431 | struct zap_details *details) |
| 1432 | { |
| 1433 | struct vm_area_struct *vma; |
| 1434 | struct prio_tree_iter iter; |
| 1435 | pgoff_t vba, vea, zba, zea; |
| 1436 | |
| 1437 | restart: |
| 1438 | vma_prio_tree_foreach(vma, &iter, root, |
| 1439 | details->first_index, details->last_index) { |
| 1440 | /* Skip quickly over those we have already dealt with */ |
| 1441 | if (vma->vm_truncate_count == details->truncate_count) |
| 1442 | continue; |
| 1443 | |
| 1444 | vba = vma->vm_pgoff; |
| 1445 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; |
| 1446 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ |
| 1447 | zba = details->first_index; |
| 1448 | if (zba < vba) |
| 1449 | zba = vba; |
| 1450 | zea = details->last_index; |
| 1451 | if (zea > vea) |
| 1452 | zea = vea; |
| 1453 | |
| 1454 | if (unmap_mapping_range_vma(vma, |
| 1455 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, |
| 1456 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, |
| 1457 | details) < 0) |
| 1458 | goto restart; |
| 1459 | } |
| 1460 | } |
| 1461 | |
| 1462 | static inline void unmap_mapping_range_list(struct list_head *head, |
| 1463 | struct zap_details *details) |
| 1464 | { |
| 1465 | struct vm_area_struct *vma; |
| 1466 | |
| 1467 | /* |
| 1468 | * In nonlinear VMAs there is no correspondence between virtual address |
| 1469 | * offset and file offset. So we must perform an exhaustive search |
| 1470 | * across *all* the pages in each nonlinear VMA, not just the pages |
| 1471 | * whose virtual address lies outside the file truncation point. |
| 1472 | */ |
| 1473 | restart: |
| 1474 | list_for_each_entry(vma, head, shared.vm_set.list) { |
| 1475 | /* Skip quickly over those we have already dealt with */ |
| 1476 | if (vma->vm_truncate_count == details->truncate_count) |
| 1477 | continue; |
| 1478 | details->nonlinear_vma = vma; |
| 1479 | if (unmap_mapping_range_vma(vma, vma->vm_start, |
| 1480 | vma->vm_end, details) < 0) |
| 1481 | goto restart; |
| 1482 | } |
| 1483 | } |
| 1484 | |
| 1485 | /** |
| 1486 | * unmap_mapping_range - unmap the portion of all mmaps |
| 1487 | * in the specified address_space corresponding to the specified |
| 1488 | * page range in the underlying file. |
Martin Waitz | 3d41088 | 2005-06-23 22:05:21 -0700 | [diff] [blame] | 1489 | * @mapping: the address space containing mmaps to be unmapped. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1490 | * @holebegin: byte in first page to unmap, relative to the start of |
| 1491 | * the underlying file. This will be rounded down to a PAGE_SIZE |
| 1492 | * boundary. Note that this is different from vmtruncate(), which |
| 1493 | * must keep the partial page. In contrast, we must get rid of |
| 1494 | * partial pages. |
| 1495 | * @holelen: size of prospective hole in bytes. This will be rounded |
| 1496 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the |
| 1497 | * end of the file. |
| 1498 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; |
| 1499 | * but 0 when invalidating pagecache, don't throw away private data. |
| 1500 | */ |
| 1501 | void unmap_mapping_range(struct address_space *mapping, |
| 1502 | loff_t const holebegin, loff_t const holelen, int even_cows) |
| 1503 | { |
| 1504 | struct zap_details details; |
| 1505 | pgoff_t hba = holebegin >> PAGE_SHIFT; |
| 1506 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1507 | |
| 1508 | /* Check for overflow. */ |
| 1509 | if (sizeof(holelen) > sizeof(hlen)) { |
| 1510 | long long holeend = |
| 1511 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1512 | if (holeend & ~(long long)ULONG_MAX) |
| 1513 | hlen = ULONG_MAX - hba + 1; |
| 1514 | } |
| 1515 | |
| 1516 | details.check_mapping = even_cows? NULL: mapping; |
| 1517 | details.nonlinear_vma = NULL; |
| 1518 | details.first_index = hba; |
| 1519 | details.last_index = hba + hlen - 1; |
| 1520 | if (details.last_index < details.first_index) |
| 1521 | details.last_index = ULONG_MAX; |
| 1522 | details.i_mmap_lock = &mapping->i_mmap_lock; |
| 1523 | |
| 1524 | spin_lock(&mapping->i_mmap_lock); |
| 1525 | |
| 1526 | /* serialize i_size write against truncate_count write */ |
| 1527 | smp_wmb(); |
| 1528 | /* Protect against page faults, and endless unmapping loops */ |
| 1529 | mapping->truncate_count++; |
| 1530 | /* |
| 1531 | * For archs where spin_lock has inclusive semantics like ia64 |
| 1532 | * this smp_mb() will prevent to read pagetable contents |
| 1533 | * before the truncate_count increment is visible to |
| 1534 | * other cpus. |
| 1535 | */ |
| 1536 | smp_mb(); |
| 1537 | if (unlikely(is_restart_addr(mapping->truncate_count))) { |
| 1538 | if (mapping->truncate_count == 0) |
| 1539 | reset_vma_truncate_counts(mapping); |
| 1540 | mapping->truncate_count++; |
| 1541 | } |
| 1542 | details.truncate_count = mapping->truncate_count; |
| 1543 | |
| 1544 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) |
| 1545 | unmap_mapping_range_tree(&mapping->i_mmap, &details); |
| 1546 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) |
| 1547 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); |
| 1548 | spin_unlock(&mapping->i_mmap_lock); |
| 1549 | } |
| 1550 | EXPORT_SYMBOL(unmap_mapping_range); |
| 1551 | |
| 1552 | /* |
| 1553 | * Handle all mappings that got truncated by a "truncate()" |
| 1554 | * system call. |
| 1555 | * |
| 1556 | * NOTE! We have to be ready to update the memory sharing |
| 1557 | * between the file and the memory map for a potential last |
| 1558 | * incomplete page. Ugly, but necessary. |
| 1559 | */ |
| 1560 | int vmtruncate(struct inode * inode, loff_t offset) |
| 1561 | { |
| 1562 | struct address_space *mapping = inode->i_mapping; |
| 1563 | unsigned long limit; |
| 1564 | |
| 1565 | if (inode->i_size < offset) |
| 1566 | goto do_expand; |
| 1567 | /* |
| 1568 | * truncation of in-use swapfiles is disallowed - it would cause |
| 1569 | * subsequent swapout to scribble on the now-freed blocks. |
| 1570 | */ |
| 1571 | if (IS_SWAPFILE(inode)) |
| 1572 | goto out_busy; |
| 1573 | i_size_write(inode, offset); |
| 1574 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); |
| 1575 | truncate_inode_pages(mapping, offset); |
| 1576 | goto out_truncate; |
| 1577 | |
| 1578 | do_expand: |
| 1579 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; |
| 1580 | if (limit != RLIM_INFINITY && offset > limit) |
| 1581 | goto out_sig; |
| 1582 | if (offset > inode->i_sb->s_maxbytes) |
| 1583 | goto out_big; |
| 1584 | i_size_write(inode, offset); |
| 1585 | |
| 1586 | out_truncate: |
| 1587 | if (inode->i_op && inode->i_op->truncate) |
| 1588 | inode->i_op->truncate(inode); |
| 1589 | return 0; |
| 1590 | out_sig: |
| 1591 | send_sig(SIGXFSZ, current, 0); |
| 1592 | out_big: |
| 1593 | return -EFBIG; |
| 1594 | out_busy: |
| 1595 | return -ETXTBSY; |
| 1596 | } |
| 1597 | |
| 1598 | EXPORT_SYMBOL(vmtruncate); |
| 1599 | |
| 1600 | /* |
| 1601 | * Primitive swap readahead code. We simply read an aligned block of |
| 1602 | * (1 << page_cluster) entries in the swap area. This method is chosen |
| 1603 | * because it doesn't cost us any seek time. We also make sure to queue |
| 1604 | * the 'original' request together with the readahead ones... |
| 1605 | * |
| 1606 | * This has been extended to use the NUMA policies from the mm triggering |
| 1607 | * the readahead. |
| 1608 | * |
| 1609 | * Caller must hold down_read on the vma->vm_mm if vma is not NULL. |
| 1610 | */ |
| 1611 | void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) |
| 1612 | { |
| 1613 | #ifdef CONFIG_NUMA |
| 1614 | struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; |
| 1615 | #endif |
| 1616 | int i, num; |
| 1617 | struct page *new_page; |
| 1618 | unsigned long offset; |
| 1619 | |
| 1620 | /* |
| 1621 | * Get the number of handles we should do readahead io to. |
| 1622 | */ |
| 1623 | num = valid_swaphandles(entry, &offset); |
| 1624 | for (i = 0; i < num; offset++, i++) { |
| 1625 | /* Ok, do the async read-ahead now */ |
| 1626 | new_page = read_swap_cache_async(swp_entry(swp_type(entry), |
| 1627 | offset), vma, addr); |
| 1628 | if (!new_page) |
| 1629 | break; |
| 1630 | page_cache_release(new_page); |
| 1631 | #ifdef CONFIG_NUMA |
| 1632 | /* |
| 1633 | * Find the next applicable VMA for the NUMA policy. |
| 1634 | */ |
| 1635 | addr += PAGE_SIZE; |
| 1636 | if (addr == 0) |
| 1637 | vma = NULL; |
| 1638 | if (vma) { |
| 1639 | if (addr >= vma->vm_end) { |
| 1640 | vma = next_vma; |
| 1641 | next_vma = vma ? vma->vm_next : NULL; |
| 1642 | } |
| 1643 | if (vma && addr < vma->vm_start) |
| 1644 | vma = NULL; |
| 1645 | } else { |
| 1646 | if (next_vma && addr >= next_vma->vm_start) { |
| 1647 | vma = next_vma; |
| 1648 | next_vma = vma->vm_next; |
| 1649 | } |
| 1650 | } |
| 1651 | #endif |
| 1652 | } |
| 1653 | lru_add_drain(); /* Push any new pages onto the LRU now */ |
| 1654 | } |
| 1655 | |
| 1656 | /* |
| 1657 | * We hold the mm semaphore and the page_table_lock on entry and |
| 1658 | * should release the pagetable lock on exit.. |
| 1659 | */ |
| 1660 | static int do_swap_page(struct mm_struct * mm, |
| 1661 | struct vm_area_struct * vma, unsigned long address, |
| 1662 | pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access) |
| 1663 | { |
| 1664 | struct page *page; |
| 1665 | swp_entry_t entry = pte_to_swp_entry(orig_pte); |
| 1666 | pte_t pte; |
| 1667 | int ret = VM_FAULT_MINOR; |
| 1668 | |
| 1669 | pte_unmap(page_table); |
| 1670 | spin_unlock(&mm->page_table_lock); |
| 1671 | page = lookup_swap_cache(entry); |
| 1672 | if (!page) { |
| 1673 | swapin_readahead(entry, address, vma); |
| 1674 | page = read_swap_cache_async(entry, vma, address); |
| 1675 | if (!page) { |
| 1676 | /* |
| 1677 | * Back out if somebody else faulted in this pte while |
| 1678 | * we released the page table lock. |
| 1679 | */ |
| 1680 | spin_lock(&mm->page_table_lock); |
| 1681 | page_table = pte_offset_map(pmd, address); |
| 1682 | if (likely(pte_same(*page_table, orig_pte))) |
| 1683 | ret = VM_FAULT_OOM; |
| 1684 | else |
| 1685 | ret = VM_FAULT_MINOR; |
| 1686 | pte_unmap(page_table); |
| 1687 | spin_unlock(&mm->page_table_lock); |
| 1688 | goto out; |
| 1689 | } |
| 1690 | |
| 1691 | /* Had to read the page from swap area: Major fault */ |
| 1692 | ret = VM_FAULT_MAJOR; |
| 1693 | inc_page_state(pgmajfault); |
| 1694 | grab_swap_token(); |
| 1695 | } |
| 1696 | |
| 1697 | mark_page_accessed(page); |
| 1698 | lock_page(page); |
| 1699 | |
| 1700 | /* |
| 1701 | * Back out if somebody else faulted in this pte while we |
| 1702 | * released the page table lock. |
| 1703 | */ |
| 1704 | spin_lock(&mm->page_table_lock); |
| 1705 | page_table = pte_offset_map(pmd, address); |
| 1706 | if (unlikely(!pte_same(*page_table, orig_pte))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1707 | ret = VM_FAULT_MINOR; |
Kirill Korotaev | b810748 | 2005-05-16 21:53:50 -0700 | [diff] [blame] | 1708 | goto out_nomap; |
| 1709 | } |
| 1710 | |
| 1711 | if (unlikely(!PageUptodate(page))) { |
| 1712 | ret = VM_FAULT_SIGBUS; |
| 1713 | goto out_nomap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1714 | } |
| 1715 | |
| 1716 | /* The page isn't present yet, go ahead with the fault. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1717 | |
| 1718 | inc_mm_counter(mm, rss); |
| 1719 | pte = mk_pte(page, vma->vm_page_prot); |
| 1720 | if (write_access && can_share_swap_page(page)) { |
| 1721 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); |
| 1722 | write_access = 0; |
| 1723 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1724 | |
| 1725 | flush_icache_page(vma, page); |
| 1726 | set_pte_at(mm, address, page_table, pte); |
| 1727 | page_add_anon_rmap(page, vma, address); |
| 1728 | |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 1729 | swap_free(entry); |
| 1730 | if (vm_swap_full()) |
| 1731 | remove_exclusive_swap_page(page); |
| 1732 | unlock_page(page); |
| 1733 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1734 | if (write_access) { |
| 1735 | if (do_wp_page(mm, vma, address, |
| 1736 | page_table, pmd, pte) == VM_FAULT_OOM) |
| 1737 | ret = VM_FAULT_OOM; |
| 1738 | goto out; |
| 1739 | } |
| 1740 | |
| 1741 | /* No need to invalidate - it was non-present before */ |
| 1742 | update_mmu_cache(vma, address, pte); |
| 1743 | lazy_mmu_prot_update(pte); |
| 1744 | pte_unmap(page_table); |
| 1745 | spin_unlock(&mm->page_table_lock); |
| 1746 | out: |
| 1747 | return ret; |
Kirill Korotaev | b810748 | 2005-05-16 21:53:50 -0700 | [diff] [blame] | 1748 | out_nomap: |
| 1749 | pte_unmap(page_table); |
| 1750 | spin_unlock(&mm->page_table_lock); |
| 1751 | unlock_page(page); |
| 1752 | page_cache_release(page); |
| 1753 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1754 | } |
| 1755 | |
| 1756 | /* |
| 1757 | * We are called with the MM semaphore and page_table_lock |
| 1758 | * spinlock held to protect against concurrent faults in |
| 1759 | * multithreaded programs. |
| 1760 | */ |
| 1761 | static int |
| 1762 | do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1763 | pte_t *page_table, pmd_t *pmd, int write_access, |
| 1764 | unsigned long addr) |
| 1765 | { |
| 1766 | pte_t entry; |
| 1767 | struct page * page = ZERO_PAGE(addr); |
| 1768 | |
| 1769 | /* Read-only mapping of ZERO_PAGE. */ |
| 1770 | entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot)); |
| 1771 | |
| 1772 | /* ..except if it's a write access */ |
| 1773 | if (write_access) { |
| 1774 | /* Allocate our own private page. */ |
| 1775 | pte_unmap(page_table); |
| 1776 | spin_unlock(&mm->page_table_lock); |
| 1777 | |
| 1778 | if (unlikely(anon_vma_prepare(vma))) |
| 1779 | goto no_mem; |
| 1780 | page = alloc_zeroed_user_highpage(vma, addr); |
| 1781 | if (!page) |
| 1782 | goto no_mem; |
| 1783 | |
| 1784 | spin_lock(&mm->page_table_lock); |
| 1785 | page_table = pte_offset_map(pmd, addr); |
| 1786 | |
| 1787 | if (!pte_none(*page_table)) { |
| 1788 | pte_unmap(page_table); |
| 1789 | page_cache_release(page); |
| 1790 | spin_unlock(&mm->page_table_lock); |
| 1791 | goto out; |
| 1792 | } |
| 1793 | inc_mm_counter(mm, rss); |
| 1794 | entry = maybe_mkwrite(pte_mkdirty(mk_pte(page, |
| 1795 | vma->vm_page_prot)), |
| 1796 | vma); |
| 1797 | lru_cache_add_active(page); |
| 1798 | SetPageReferenced(page); |
| 1799 | page_add_anon_rmap(page, vma, addr); |
| 1800 | } |
| 1801 | |
| 1802 | set_pte_at(mm, addr, page_table, entry); |
| 1803 | pte_unmap(page_table); |
| 1804 | |
| 1805 | /* No need to invalidate - it was non-present before */ |
| 1806 | update_mmu_cache(vma, addr, entry); |
| 1807 | lazy_mmu_prot_update(entry); |
| 1808 | spin_unlock(&mm->page_table_lock); |
| 1809 | out: |
| 1810 | return VM_FAULT_MINOR; |
| 1811 | no_mem: |
| 1812 | return VM_FAULT_OOM; |
| 1813 | } |
| 1814 | |
| 1815 | /* |
| 1816 | * do_no_page() tries to create a new page mapping. It aggressively |
| 1817 | * tries to share with existing pages, but makes a separate copy if |
| 1818 | * the "write_access" parameter is true in order to avoid the next |
| 1819 | * page fault. |
| 1820 | * |
| 1821 | * As this is called only for pages that do not currently exist, we |
| 1822 | * do not need to flush old virtual caches or the TLB. |
| 1823 | * |
| 1824 | * This is called with the MM semaphore held and the page table |
| 1825 | * spinlock held. Exit with the spinlock released. |
| 1826 | */ |
| 1827 | static int |
| 1828 | do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1829 | unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd) |
| 1830 | { |
| 1831 | struct page * new_page; |
| 1832 | struct address_space *mapping = NULL; |
| 1833 | pte_t entry; |
| 1834 | unsigned int sequence = 0; |
| 1835 | int ret = VM_FAULT_MINOR; |
| 1836 | int anon = 0; |
| 1837 | |
| 1838 | if (!vma->vm_ops || !vma->vm_ops->nopage) |
| 1839 | return do_anonymous_page(mm, vma, page_table, |
| 1840 | pmd, write_access, address); |
| 1841 | pte_unmap(page_table); |
| 1842 | spin_unlock(&mm->page_table_lock); |
| 1843 | |
| 1844 | if (vma->vm_file) { |
| 1845 | mapping = vma->vm_file->f_mapping; |
| 1846 | sequence = mapping->truncate_count; |
| 1847 | smp_rmb(); /* serializes i_size against truncate_count */ |
| 1848 | } |
| 1849 | retry: |
| 1850 | cond_resched(); |
| 1851 | new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); |
| 1852 | /* |
| 1853 | * No smp_rmb is needed here as long as there's a full |
| 1854 | * spin_lock/unlock sequence inside the ->nopage callback |
| 1855 | * (for the pagecache lookup) that acts as an implicit |
| 1856 | * smp_mb() and prevents the i_size read to happen |
| 1857 | * after the next truncate_count read. |
| 1858 | */ |
| 1859 | |
| 1860 | /* no page was available -- either SIGBUS or OOM */ |
| 1861 | if (new_page == NOPAGE_SIGBUS) |
| 1862 | return VM_FAULT_SIGBUS; |
| 1863 | if (new_page == NOPAGE_OOM) |
| 1864 | return VM_FAULT_OOM; |
| 1865 | |
| 1866 | /* |
| 1867 | * Should we do an early C-O-W break? |
| 1868 | */ |
| 1869 | if (write_access && !(vma->vm_flags & VM_SHARED)) { |
| 1870 | struct page *page; |
| 1871 | |
| 1872 | if (unlikely(anon_vma_prepare(vma))) |
| 1873 | goto oom; |
| 1874 | page = alloc_page_vma(GFP_HIGHUSER, vma, address); |
| 1875 | if (!page) |
| 1876 | goto oom; |
| 1877 | copy_user_highpage(page, new_page, address); |
| 1878 | page_cache_release(new_page); |
| 1879 | new_page = page; |
| 1880 | anon = 1; |
| 1881 | } |
| 1882 | |
| 1883 | spin_lock(&mm->page_table_lock); |
| 1884 | /* |
| 1885 | * For a file-backed vma, someone could have truncated or otherwise |
| 1886 | * invalidated this page. If unmap_mapping_range got called, |
| 1887 | * retry getting the page. |
| 1888 | */ |
| 1889 | if (mapping && unlikely(sequence != mapping->truncate_count)) { |
| 1890 | sequence = mapping->truncate_count; |
| 1891 | spin_unlock(&mm->page_table_lock); |
| 1892 | page_cache_release(new_page); |
| 1893 | goto retry; |
| 1894 | } |
| 1895 | page_table = pte_offset_map(pmd, address); |
| 1896 | |
| 1897 | /* |
| 1898 | * This silly early PAGE_DIRTY setting removes a race |
| 1899 | * due to the bad i386 page protection. But it's valid |
| 1900 | * for other architectures too. |
| 1901 | * |
| 1902 | * Note that if write_access is true, we either now have |
| 1903 | * an exclusive copy of the page, or this is a shared mapping, |
| 1904 | * so we can make it writable and dirty to avoid having to |
| 1905 | * handle that later. |
| 1906 | */ |
| 1907 | /* Only go through if we didn't race with anybody else... */ |
| 1908 | if (pte_none(*page_table)) { |
| 1909 | if (!PageReserved(new_page)) |
| 1910 | inc_mm_counter(mm, rss); |
| 1911 | |
| 1912 | flush_icache_page(vma, new_page); |
| 1913 | entry = mk_pte(new_page, vma->vm_page_prot); |
| 1914 | if (write_access) |
| 1915 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
| 1916 | set_pte_at(mm, address, page_table, entry); |
| 1917 | if (anon) { |
| 1918 | lru_cache_add_active(new_page); |
| 1919 | page_add_anon_rmap(new_page, vma, address); |
| 1920 | } else |
| 1921 | page_add_file_rmap(new_page); |
| 1922 | pte_unmap(page_table); |
| 1923 | } else { |
| 1924 | /* One of our sibling threads was faster, back out. */ |
| 1925 | pte_unmap(page_table); |
| 1926 | page_cache_release(new_page); |
| 1927 | spin_unlock(&mm->page_table_lock); |
| 1928 | goto out; |
| 1929 | } |
| 1930 | |
| 1931 | /* no need to invalidate: a not-present page shouldn't be cached */ |
| 1932 | update_mmu_cache(vma, address, entry); |
| 1933 | lazy_mmu_prot_update(entry); |
| 1934 | spin_unlock(&mm->page_table_lock); |
| 1935 | out: |
| 1936 | return ret; |
| 1937 | oom: |
| 1938 | page_cache_release(new_page); |
| 1939 | ret = VM_FAULT_OOM; |
| 1940 | goto out; |
| 1941 | } |
| 1942 | |
| 1943 | /* |
| 1944 | * Fault of a previously existing named mapping. Repopulate the pte |
| 1945 | * from the encoded file_pte if possible. This enables swappable |
| 1946 | * nonlinear vmas. |
| 1947 | */ |
| 1948 | static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma, |
| 1949 | unsigned long address, int write_access, pte_t *pte, pmd_t *pmd) |
| 1950 | { |
| 1951 | unsigned long pgoff; |
| 1952 | int err; |
| 1953 | |
| 1954 | BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage); |
| 1955 | /* |
| 1956 | * Fall back to the linear mapping if the fs does not support |
| 1957 | * ->populate: |
| 1958 | */ |
Paolo 'Blaisorblade' Giarrusso | 4944e76 | 2005-09-03 15:54:56 -0700 | [diff] [blame] | 1959 | if (!vma->vm_ops->populate || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1960 | (write_access && !(vma->vm_flags & VM_SHARED))) { |
| 1961 | pte_clear(mm, address, pte); |
| 1962 | return do_no_page(mm, vma, address, write_access, pte, pmd); |
| 1963 | } |
| 1964 | |
| 1965 | pgoff = pte_to_pgoff(*pte); |
| 1966 | |
| 1967 | pte_unmap(pte); |
| 1968 | spin_unlock(&mm->page_table_lock); |
| 1969 | |
| 1970 | err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0); |
| 1971 | if (err == -ENOMEM) |
| 1972 | return VM_FAULT_OOM; |
| 1973 | if (err) |
| 1974 | return VM_FAULT_SIGBUS; |
| 1975 | return VM_FAULT_MAJOR; |
| 1976 | } |
| 1977 | |
| 1978 | /* |
| 1979 | * These routines also need to handle stuff like marking pages dirty |
| 1980 | * and/or accessed for architectures that don't do it in hardware (most |
| 1981 | * RISC architectures). The early dirtying is also good on the i386. |
| 1982 | * |
| 1983 | * There is also a hook called "update_mmu_cache()" that architectures |
| 1984 | * with external mmu caches can use to update those (ie the Sparc or |
| 1985 | * PowerPC hashed page tables that act as extended TLBs). |
| 1986 | * |
| 1987 | * Note the "page_table_lock". It is to protect against kswapd removing |
| 1988 | * pages from under us. Note that kswapd only ever _removes_ pages, never |
| 1989 | * adds them. As such, once we have noticed that the page is not present, |
| 1990 | * we can drop the lock early. |
| 1991 | * |
| 1992 | * The adding of pages is protected by the MM semaphore (which we hold), |
| 1993 | * so we don't need to worry about a page being suddenly been added into |
| 1994 | * our VM. |
| 1995 | * |
| 1996 | * We enter with the pagetable spinlock held, we are supposed to |
| 1997 | * release it when done. |
| 1998 | */ |
| 1999 | static inline int handle_pte_fault(struct mm_struct *mm, |
| 2000 | struct vm_area_struct * vma, unsigned long address, |
| 2001 | int write_access, pte_t *pte, pmd_t *pmd) |
| 2002 | { |
| 2003 | pte_t entry; |
| 2004 | |
| 2005 | entry = *pte; |
| 2006 | if (!pte_present(entry)) { |
| 2007 | /* |
| 2008 | * If it truly wasn't present, we know that kswapd |
| 2009 | * and the PTE updates will not touch it later. So |
| 2010 | * drop the lock. |
| 2011 | */ |
| 2012 | if (pte_none(entry)) |
| 2013 | return do_no_page(mm, vma, address, write_access, pte, pmd); |
| 2014 | if (pte_file(entry)) |
| 2015 | return do_file_page(mm, vma, address, write_access, pte, pmd); |
| 2016 | return do_swap_page(mm, vma, address, pte, pmd, entry, write_access); |
| 2017 | } |
| 2018 | |
| 2019 | if (write_access) { |
| 2020 | if (!pte_write(entry)) |
| 2021 | return do_wp_page(mm, vma, address, pte, pmd, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2022 | entry = pte_mkdirty(entry); |
| 2023 | } |
| 2024 | entry = pte_mkyoung(entry); |
| 2025 | ptep_set_access_flags(vma, address, pte, entry, write_access); |
| 2026 | update_mmu_cache(vma, address, entry); |
| 2027 | lazy_mmu_prot_update(entry); |
| 2028 | pte_unmap(pte); |
| 2029 | spin_unlock(&mm->page_table_lock); |
| 2030 | return VM_FAULT_MINOR; |
| 2031 | } |
| 2032 | |
| 2033 | /* |
| 2034 | * By the time we get here, we already hold the mm semaphore |
| 2035 | */ |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 2036 | int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2037 | unsigned long address, int write_access) |
| 2038 | { |
| 2039 | pgd_t *pgd; |
| 2040 | pud_t *pud; |
| 2041 | pmd_t *pmd; |
| 2042 | pte_t *pte; |
| 2043 | |
| 2044 | __set_current_state(TASK_RUNNING); |
| 2045 | |
| 2046 | inc_page_state(pgfault); |
| 2047 | |
Hugh Dickins | ac9b9c6 | 2005-10-20 16:24:28 +0100 | [diff] [blame] | 2048 | if (unlikely(is_vm_hugetlb_page(vma))) |
| 2049 | return hugetlb_fault(mm, vma, address, write_access); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2050 | |
| 2051 | /* |
| 2052 | * We need the page table lock to synchronize with kswapd |
| 2053 | * and the SMP-safe atomic PTE updates. |
| 2054 | */ |
| 2055 | pgd = pgd_offset(mm, address); |
| 2056 | spin_lock(&mm->page_table_lock); |
| 2057 | |
| 2058 | pud = pud_alloc(mm, pgd, address); |
| 2059 | if (!pud) |
| 2060 | goto oom; |
| 2061 | |
| 2062 | pmd = pmd_alloc(mm, pud, address); |
| 2063 | if (!pmd) |
| 2064 | goto oom; |
| 2065 | |
| 2066 | pte = pte_alloc_map(mm, pmd, address); |
| 2067 | if (!pte) |
| 2068 | goto oom; |
| 2069 | |
| 2070 | return handle_pte_fault(mm, vma, address, write_access, pte, pmd); |
| 2071 | |
| 2072 | oom: |
| 2073 | spin_unlock(&mm->page_table_lock); |
| 2074 | return VM_FAULT_OOM; |
| 2075 | } |
| 2076 | |
| 2077 | #ifndef __PAGETABLE_PUD_FOLDED |
| 2078 | /* |
| 2079 | * Allocate page upper directory. |
| 2080 | * |
| 2081 | * We've already handled the fast-path in-line, and we own the |
| 2082 | * page table lock. |
| 2083 | */ |
| 2084 | pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
| 2085 | { |
| 2086 | pud_t *new; |
| 2087 | |
| 2088 | spin_unlock(&mm->page_table_lock); |
| 2089 | new = pud_alloc_one(mm, address); |
| 2090 | spin_lock(&mm->page_table_lock); |
| 2091 | if (!new) |
| 2092 | return NULL; |
| 2093 | |
| 2094 | /* |
| 2095 | * Because we dropped the lock, we should re-check the |
| 2096 | * entry, as somebody else could have populated it.. |
| 2097 | */ |
| 2098 | if (pgd_present(*pgd)) { |
| 2099 | pud_free(new); |
| 2100 | goto out; |
| 2101 | } |
| 2102 | pgd_populate(mm, pgd, new); |
| 2103 | out: |
| 2104 | return pud_offset(pgd, address); |
| 2105 | } |
| 2106 | #endif /* __PAGETABLE_PUD_FOLDED */ |
| 2107 | |
| 2108 | #ifndef __PAGETABLE_PMD_FOLDED |
| 2109 | /* |
| 2110 | * Allocate page middle directory. |
| 2111 | * |
| 2112 | * We've already handled the fast-path in-line, and we own the |
| 2113 | * page table lock. |
| 2114 | */ |
| 2115 | pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
| 2116 | { |
| 2117 | pmd_t *new; |
| 2118 | |
| 2119 | spin_unlock(&mm->page_table_lock); |
| 2120 | new = pmd_alloc_one(mm, address); |
| 2121 | spin_lock(&mm->page_table_lock); |
| 2122 | if (!new) |
| 2123 | return NULL; |
| 2124 | |
| 2125 | /* |
| 2126 | * Because we dropped the lock, we should re-check the |
| 2127 | * entry, as somebody else could have populated it.. |
| 2128 | */ |
| 2129 | #ifndef __ARCH_HAS_4LEVEL_HACK |
| 2130 | if (pud_present(*pud)) { |
| 2131 | pmd_free(new); |
| 2132 | goto out; |
| 2133 | } |
| 2134 | pud_populate(mm, pud, new); |
| 2135 | #else |
| 2136 | if (pgd_present(*pud)) { |
| 2137 | pmd_free(new); |
| 2138 | goto out; |
| 2139 | } |
| 2140 | pgd_populate(mm, pud, new); |
| 2141 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
| 2142 | |
| 2143 | out: |
| 2144 | return pmd_offset(pud, address); |
| 2145 | } |
| 2146 | #endif /* __PAGETABLE_PMD_FOLDED */ |
| 2147 | |
| 2148 | int make_pages_present(unsigned long addr, unsigned long end) |
| 2149 | { |
| 2150 | int ret, len, write; |
| 2151 | struct vm_area_struct * vma; |
| 2152 | |
| 2153 | vma = find_vma(current->mm, addr); |
| 2154 | if (!vma) |
| 2155 | return -1; |
| 2156 | write = (vma->vm_flags & VM_WRITE) != 0; |
| 2157 | if (addr >= end) |
| 2158 | BUG(); |
| 2159 | if (end > vma->vm_end) |
| 2160 | BUG(); |
| 2161 | len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; |
| 2162 | ret = get_user_pages(current, current->mm, addr, |
| 2163 | len, write, 0, NULL, NULL); |
| 2164 | if (ret < 0) |
| 2165 | return ret; |
| 2166 | return ret == len ? 0 : -1; |
| 2167 | } |
| 2168 | |
| 2169 | /* |
| 2170 | * Map a vmalloc()-space virtual address to the physical page. |
| 2171 | */ |
| 2172 | struct page * vmalloc_to_page(void * vmalloc_addr) |
| 2173 | { |
| 2174 | unsigned long addr = (unsigned long) vmalloc_addr; |
| 2175 | struct page *page = NULL; |
| 2176 | pgd_t *pgd = pgd_offset_k(addr); |
| 2177 | pud_t *pud; |
| 2178 | pmd_t *pmd; |
| 2179 | pte_t *ptep, pte; |
| 2180 | |
| 2181 | if (!pgd_none(*pgd)) { |
| 2182 | pud = pud_offset(pgd, addr); |
| 2183 | if (!pud_none(*pud)) { |
| 2184 | pmd = pmd_offset(pud, addr); |
| 2185 | if (!pmd_none(*pmd)) { |
| 2186 | ptep = pte_offset_map(pmd, addr); |
| 2187 | pte = *ptep; |
| 2188 | if (pte_present(pte)) |
| 2189 | page = pte_page(pte); |
| 2190 | pte_unmap(ptep); |
| 2191 | } |
| 2192 | } |
| 2193 | } |
| 2194 | return page; |
| 2195 | } |
| 2196 | |
| 2197 | EXPORT_SYMBOL(vmalloc_to_page); |
| 2198 | |
| 2199 | /* |
| 2200 | * Map a vmalloc()-space virtual address to the physical page frame number. |
| 2201 | */ |
| 2202 | unsigned long vmalloc_to_pfn(void * vmalloc_addr) |
| 2203 | { |
| 2204 | return page_to_pfn(vmalloc_to_page(vmalloc_addr)); |
| 2205 | } |
| 2206 | |
| 2207 | EXPORT_SYMBOL(vmalloc_to_pfn); |
| 2208 | |
| 2209 | /* |
| 2210 | * update_mem_hiwater |
| 2211 | * - update per process rss and vm high water data |
| 2212 | */ |
| 2213 | void update_mem_hiwater(struct task_struct *tsk) |
| 2214 | { |
| 2215 | if (tsk->mm) { |
| 2216 | unsigned long rss = get_mm_counter(tsk->mm, rss); |
| 2217 | |
| 2218 | if (tsk->mm->hiwater_rss < rss) |
| 2219 | tsk->mm->hiwater_rss = rss; |
| 2220 | if (tsk->mm->hiwater_vm < tsk->mm->total_vm) |
| 2221 | tsk->mm->hiwater_vm = tsk->mm->total_vm; |
| 2222 | } |
| 2223 | } |
| 2224 | |
| 2225 | #if !defined(__HAVE_ARCH_GATE_AREA) |
| 2226 | |
| 2227 | #if defined(AT_SYSINFO_EHDR) |
Adrian Bunk | 5ce7852 | 2005-09-10 00:26:28 -0700 | [diff] [blame] | 2228 | static struct vm_area_struct gate_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2229 | |
| 2230 | static int __init gate_vma_init(void) |
| 2231 | { |
| 2232 | gate_vma.vm_mm = NULL; |
| 2233 | gate_vma.vm_start = FIXADDR_USER_START; |
| 2234 | gate_vma.vm_end = FIXADDR_USER_END; |
| 2235 | gate_vma.vm_page_prot = PAGE_READONLY; |
| 2236 | gate_vma.vm_flags = 0; |
| 2237 | return 0; |
| 2238 | } |
| 2239 | __initcall(gate_vma_init); |
| 2240 | #endif |
| 2241 | |
| 2242 | struct vm_area_struct *get_gate_vma(struct task_struct *tsk) |
| 2243 | { |
| 2244 | #ifdef AT_SYSINFO_EHDR |
| 2245 | return &gate_vma; |
| 2246 | #else |
| 2247 | return NULL; |
| 2248 | #endif |
| 2249 | } |
| 2250 | |
| 2251 | int in_gate_area_no_task(unsigned long addr) |
| 2252 | { |
| 2253 | #ifdef AT_SYSINFO_EHDR |
| 2254 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) |
| 2255 | return 1; |
| 2256 | #endif |
| 2257 | return 0; |
| 2258 | } |
| 2259 | |
| 2260 | #endif /* __HAVE_ARCH_GATE_AREA */ |