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> |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 50 | #include <linux/delayacct.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 51 | #include <linux/init.h> |
Peter Zijlstra | edc79b2 | 2006-09-25 23:30:58 -0700 | [diff] [blame] | 52 | #include <linux/writeback.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | |
| 54 | #include <asm/pgalloc.h> |
| 55 | #include <asm/uaccess.h> |
| 56 | #include <asm/tlb.h> |
| 57 | #include <asm/tlbflush.h> |
| 58 | #include <asm/pgtable.h> |
| 59 | |
| 60 | #include <linux/swapops.h> |
| 61 | #include <linux/elf.h> |
| 62 | |
Andy Whitcroft | d41dee3 | 2005-06-23 00:07:54 -0700 | [diff] [blame] | 63 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
| 65 | unsigned long max_mapnr; |
| 66 | struct page *mem_map; |
| 67 | |
| 68 | EXPORT_SYMBOL(max_mapnr); |
| 69 | EXPORT_SYMBOL(mem_map); |
| 70 | #endif |
| 71 | |
| 72 | unsigned long num_physpages; |
| 73 | /* |
| 74 | * A number of key systems in x86 including ioremap() rely on the assumption |
| 75 | * that high_memory defines the upper bound on direct map memory, then end |
| 76 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and |
| 77 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL |
| 78 | * and ZONE_HIGHMEM. |
| 79 | */ |
| 80 | void * high_memory; |
| 81 | unsigned long vmalloc_earlyreserve; |
| 82 | |
| 83 | EXPORT_SYMBOL(num_physpages); |
| 84 | EXPORT_SYMBOL(high_memory); |
| 85 | EXPORT_SYMBOL(vmalloc_earlyreserve); |
| 86 | |
Andi Kleen | a62eaf1 | 2006-02-16 23:41:58 +0100 | [diff] [blame] | 87 | int randomize_va_space __read_mostly = 1; |
| 88 | |
| 89 | static int __init disable_randmaps(char *s) |
| 90 | { |
| 91 | randomize_va_space = 0; |
OGAWA Hirofumi | 9b41046 | 2006-03-31 02:30:33 -0800 | [diff] [blame] | 92 | return 1; |
Andi Kleen | a62eaf1 | 2006-02-16 23:41:58 +0100 | [diff] [blame] | 93 | } |
| 94 | __setup("norandmaps", disable_randmaps); |
| 95 | |
| 96 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 97 | /* |
| 98 | * If a p?d_bad entry is found while walking page tables, report |
| 99 | * the error, before resetting entry to p?d_none. Usually (but |
| 100 | * very seldom) called out from the p?d_none_or_clear_bad macros. |
| 101 | */ |
| 102 | |
| 103 | void pgd_clear_bad(pgd_t *pgd) |
| 104 | { |
| 105 | pgd_ERROR(*pgd); |
| 106 | pgd_clear(pgd); |
| 107 | } |
| 108 | |
| 109 | void pud_clear_bad(pud_t *pud) |
| 110 | { |
| 111 | pud_ERROR(*pud); |
| 112 | pud_clear(pud); |
| 113 | } |
| 114 | |
| 115 | void pmd_clear_bad(pmd_t *pmd) |
| 116 | { |
| 117 | pmd_ERROR(*pmd); |
| 118 | pmd_clear(pmd); |
| 119 | } |
| 120 | |
| 121 | /* |
| 122 | * Note: this doesn't free the actual pages themselves. That |
| 123 | * has been handled earlier when unmapping all the memory regions. |
| 124 | */ |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 125 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | { |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 127 | struct page *page = pmd_page(*pmd); |
| 128 | pmd_clear(pmd); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 129 | pte_lock_deinit(page); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 130 | pte_free_tlb(tlb, page); |
Christoph Lameter | df849a1 | 2006-06-30 01:55:38 -0700 | [diff] [blame] | 131 | dec_zone_page_state(page, NR_PAGETABLE); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 132 | tlb->mm->nr_ptes--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 133 | } |
| 134 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 135 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
| 136 | unsigned long addr, unsigned long end, |
| 137 | unsigned long floor, unsigned long ceiling) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | { |
| 139 | pmd_t *pmd; |
| 140 | unsigned long next; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 141 | unsigned long start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 142 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 143 | start = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | pmd = pmd_offset(pud, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | do { |
| 146 | next = pmd_addr_end(addr, end); |
| 147 | if (pmd_none_or_clear_bad(pmd)) |
| 148 | continue; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 149 | free_pte_range(tlb, pmd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 150 | } while (pmd++, addr = next, addr != end); |
| 151 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 152 | start &= PUD_MASK; |
| 153 | if (start < floor) |
| 154 | return; |
| 155 | if (ceiling) { |
| 156 | ceiling &= PUD_MASK; |
| 157 | if (!ceiling) |
| 158 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | } |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 160 | if (end - 1 > ceiling - 1) |
| 161 | return; |
| 162 | |
| 163 | pmd = pmd_offset(pud, start); |
| 164 | pud_clear(pud); |
| 165 | pmd_free_tlb(tlb, pmd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | } |
| 167 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 168 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
| 169 | unsigned long addr, unsigned long end, |
| 170 | unsigned long floor, unsigned long ceiling) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | { |
| 172 | pud_t *pud; |
| 173 | unsigned long next; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 174 | unsigned long start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 176 | start = addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | pud = pud_offset(pgd, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 178 | do { |
| 179 | next = pud_addr_end(addr, end); |
| 180 | if (pud_none_or_clear_bad(pud)) |
| 181 | continue; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 182 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | } while (pud++, addr = next, addr != end); |
| 184 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 185 | start &= PGDIR_MASK; |
| 186 | if (start < floor) |
| 187 | return; |
| 188 | if (ceiling) { |
| 189 | ceiling &= PGDIR_MASK; |
| 190 | if (!ceiling) |
| 191 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | } |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 193 | if (end - 1 > ceiling - 1) |
| 194 | return; |
| 195 | |
| 196 | pud = pud_offset(pgd, start); |
| 197 | pgd_clear(pgd); |
| 198 | pud_free_tlb(tlb, pud); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | } |
| 200 | |
| 201 | /* |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 202 | * This function frees user-level page tables of a process. |
| 203 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | * Must be called with pagetable lock held. |
| 205 | */ |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 206 | void free_pgd_range(struct mmu_gather **tlb, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 207 | unsigned long addr, unsigned long end, |
| 208 | unsigned long floor, unsigned long ceiling) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | { |
| 210 | pgd_t *pgd; |
| 211 | unsigned long next; |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 212 | unsigned long start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 213 | |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 214 | /* |
| 215 | * The next few lines have given us lots of grief... |
| 216 | * |
| 217 | * Why are we testing PMD* at this top level? Because often |
| 218 | * there will be no work to do at all, and we'd prefer not to |
| 219 | * go all the way down to the bottom just to discover that. |
| 220 | * |
| 221 | * Why all these "- 1"s? Because 0 represents both the bottom |
| 222 | * of the address space and the top of it (using -1 for the |
| 223 | * top wouldn't help much: the masks would do the wrong thing). |
| 224 | * The rule is that addr 0 and floor 0 refer to the bottom of |
| 225 | * the address space, but end 0 and ceiling 0 refer to the top |
| 226 | * Comparisons need to use "end - 1" and "ceiling - 1" (though |
| 227 | * that end 0 case should be mythical). |
| 228 | * |
| 229 | * Wherever addr is brought up or ceiling brought down, we must |
| 230 | * be careful to reject "the opposite 0" before it confuses the |
| 231 | * subsequent tests. But what about where end is brought down |
| 232 | * by PMD_SIZE below? no, end can't go down to 0 there. |
| 233 | * |
| 234 | * Whereas we round start (addr) and ceiling down, by different |
| 235 | * masks at different levels, in order to test whether a table |
| 236 | * now has no other vmas using it, so can be freed, we don't |
| 237 | * bother to round floor or end up - the tests don't need that. |
| 238 | */ |
| 239 | |
| 240 | addr &= PMD_MASK; |
| 241 | if (addr < floor) { |
| 242 | addr += PMD_SIZE; |
| 243 | if (!addr) |
| 244 | return; |
| 245 | } |
| 246 | if (ceiling) { |
| 247 | ceiling &= PMD_MASK; |
| 248 | if (!ceiling) |
| 249 | return; |
| 250 | } |
| 251 | if (end - 1 > ceiling - 1) |
| 252 | end -= PMD_SIZE; |
| 253 | if (addr > end - 1) |
| 254 | return; |
| 255 | |
| 256 | start = addr; |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 257 | pgd = pgd_offset((*tlb)->mm, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | do { |
| 259 | next = pgd_addr_end(addr, end); |
| 260 | if (pgd_none_or_clear_bad(pgd)) |
| 261 | continue; |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 262 | free_pud_range(*tlb, pgd, addr, next, floor, ceiling); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 263 | } while (pgd++, addr = next, addr != end); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 264 | |
Hugh Dickins | 4d6ddfa | 2005-10-29 18:16:02 -0700 | [diff] [blame] | 265 | if (!(*tlb)->fullmm) |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 266 | flush_tlb_pgtables((*tlb)->mm, start, end); |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 267 | } |
| 268 | |
| 269 | void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 270 | unsigned long floor, unsigned long ceiling) |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 271 | { |
| 272 | while (vma) { |
| 273 | struct vm_area_struct *next = vma->vm_next; |
| 274 | unsigned long addr = vma->vm_start; |
| 275 | |
Hugh Dickins | 8f4f8c1 | 2005-10-29 18:16:29 -0700 | [diff] [blame] | 276 | /* |
| 277 | * Hide vma from rmap and vmtruncate before freeing pgtables |
| 278 | */ |
| 279 | anon_vma_unlink(vma); |
| 280 | unlink_file_vma(vma); |
| 281 | |
David Gibson | 9da61ae | 2006-03-22 00:08:57 -0800 | [diff] [blame] | 282 | if (is_vm_hugetlb_page(vma)) { |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 283 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 284 | floor, next? next->vm_start: ceiling); |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 285 | } else { |
| 286 | /* |
| 287 | * Optimization: gather nearby vmas into one call down |
| 288 | */ |
| 289 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE |
David Gibson | 4866920 | 2006-03-22 00:08:58 -0800 | [diff] [blame] | 290 | && !is_vm_hugetlb_page(next)) { |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 291 | vma = next; |
| 292 | next = vma->vm_next; |
Hugh Dickins | 8f4f8c1 | 2005-10-29 18:16:29 -0700 | [diff] [blame] | 293 | anon_vma_unlink(vma); |
| 294 | unlink_file_vma(vma); |
Hugh Dickins | 3bf5ee9 | 2005-04-19 13:29:16 -0700 | [diff] [blame] | 295 | } |
| 296 | free_pgd_range(tlb, addr, vma->vm_end, |
| 297 | floor, next? next->vm_start: ceiling); |
| 298 | } |
Hugh Dickins | e0da382 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 299 | vma = next; |
| 300 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | } |
| 302 | |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 303 | int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | { |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 305 | struct page *new = pte_alloc_one(mm, address); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 306 | if (!new) |
| 307 | return -ENOMEM; |
| 308 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 309 | pte_lock_init(new); |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 310 | spin_lock(&mm->page_table_lock); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 311 | if (pmd_present(*pmd)) { /* Another has populated it */ |
| 312 | pte_lock_deinit(new); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 313 | pte_free(new); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 314 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 315 | mm->nr_ptes++; |
Christoph Lameter | df849a1 | 2006-06-30 01:55:38 -0700 | [diff] [blame] | 316 | inc_zone_page_state(new, NR_PAGETABLE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | pmd_populate(mm, pmd, new); |
| 318 | } |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 319 | spin_unlock(&mm->page_table_lock); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 320 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | } |
| 322 | |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 323 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | { |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 325 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
| 326 | if (!new) |
| 327 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 329 | spin_lock(&init_mm.page_table_lock); |
| 330 | if (pmd_present(*pmd)) /* Another has populated it */ |
| 331 | pte_free_kernel(new); |
| 332 | else |
| 333 | pmd_populate_kernel(&init_mm, pmd, new); |
| 334 | spin_unlock(&init_mm.page_table_lock); |
| 335 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | } |
| 337 | |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 338 | static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) |
| 339 | { |
| 340 | if (file_rss) |
| 341 | add_mm_counter(mm, file_rss, file_rss); |
| 342 | if (anon_rss) |
| 343 | add_mm_counter(mm, anon_rss, anon_rss); |
| 344 | } |
| 345 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | /* |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 347 | * This function is called to print an error when a bad pte |
| 348 | * is found. For example, we might have a PFN-mapped pte in |
| 349 | * a region that doesn't allow it. |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 350 | * |
| 351 | * The calling function must still handle the error. |
| 352 | */ |
| 353 | void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) |
| 354 | { |
| 355 | printk(KERN_ERR "Bad pte = %08llx, process = %s, " |
| 356 | "vm_flags = %lx, vaddr = %lx\n", |
| 357 | (long long)pte_val(pte), |
| 358 | (vma->vm_mm == current->mm ? current->comm : "???"), |
| 359 | vma->vm_flags, vaddr); |
| 360 | dump_stack(); |
| 361 | } |
| 362 | |
Linus Torvalds | 6712117 | 2005-12-11 20:38:17 -0800 | [diff] [blame] | 363 | static inline int is_cow_mapping(unsigned int flags) |
| 364 | { |
| 365 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
| 366 | } |
| 367 | |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 368 | /* |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 369 | * This function gets the "struct page" associated with a pte. |
| 370 | * |
| 371 | * NOTE! Some mappings do not have "struct pages". A raw PFN mapping |
| 372 | * will have each page table entry just pointing to a raw page frame |
| 373 | * number, and as far as the VM layer is concerned, those do not have |
| 374 | * pages associated with them - even if the PFN might point to memory |
| 375 | * that otherwise is perfectly fine and has a "struct page". |
| 376 | * |
| 377 | * The way we recognize those mappings is through the rules set up |
| 378 | * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set, |
| 379 | * and the vm_pgoff will point to the first PFN mapped: thus every |
| 380 | * page that is a raw mapping will always honor the rule |
| 381 | * |
| 382 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) |
| 383 | * |
| 384 | * and if that isn't true, the page has been COW'ed (in which case it |
| 385 | * _does_ have a "struct page" associated with it even if it is in a |
| 386 | * VM_PFNMAP range). |
Hugh Dickins | ee498ed | 2005-11-21 21:32:18 -0800 | [diff] [blame] | 387 | */ |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 388 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte) |
Hugh Dickins | ee498ed | 2005-11-21 21:32:18 -0800 | [diff] [blame] | 389 | { |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 390 | unsigned long pfn = pte_pfn(pte); |
| 391 | |
Nick Piggin | b7ab795 | 2006-03-22 00:08:42 -0800 | [diff] [blame] | 392 | if (unlikely(vma->vm_flags & VM_PFNMAP)) { |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 393 | unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT; |
| 394 | if (pfn == vma->vm_pgoff + off) |
| 395 | return NULL; |
Linus Torvalds | 6712117 | 2005-12-11 20:38:17 -0800 | [diff] [blame] | 396 | if (!is_cow_mapping(vma->vm_flags)) |
Linus Torvalds | fb155c1 | 2005-12-11 19:46:02 -0800 | [diff] [blame] | 397 | return NULL; |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 398 | } |
| 399 | |
Nick Piggin | 315ab19 | 2006-03-25 16:20:22 +0100 | [diff] [blame] | 400 | /* |
| 401 | * Add some anal sanity checks for now. Eventually, |
| 402 | * we should just do "return pfn_to_page(pfn)", but |
| 403 | * in the meantime we check that we get a valid pfn, |
| 404 | * and that the resulting page looks ok. |
| 405 | */ |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 406 | if (unlikely(!pfn_valid(pfn))) { |
| 407 | print_bad_pte(vma, pte, addr); |
| 408 | return NULL; |
| 409 | } |
| 410 | |
| 411 | /* |
| 412 | * NOTE! We still have PageReserved() pages in the page |
| 413 | * tables. |
| 414 | * |
| 415 | * The PAGE_ZERO() pages and various VDSO mappings can |
| 416 | * cause them to exist. |
| 417 | */ |
| 418 | return pfn_to_page(pfn); |
Hugh Dickins | ee498ed | 2005-11-21 21:32:18 -0800 | [diff] [blame] | 419 | } |
| 420 | |
| 421 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 422 | * copy one vm_area from one task to the other. Assumes the page tables |
| 423 | * already present in the new task to be cleared in the whole range |
| 424 | * covered by this vma. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | */ |
| 426 | |
Hugh Dickins | 8c10376 | 2005-10-29 18:16:13 -0700 | [diff] [blame] | 427 | static inline void |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 429 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
Hugh Dickins | 8c10376 | 2005-10-29 18:16:13 -0700 | [diff] [blame] | 430 | unsigned long addr, int *rss) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 431 | { |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 432 | unsigned long vm_flags = vma->vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | pte_t pte = *src_pte; |
| 434 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 435 | |
| 436 | /* pte contains position in swap or file, so copy. */ |
| 437 | if (unlikely(!pte_present(pte))) { |
| 438 | if (!pte_file(pte)) { |
Christoph Lameter | 0697212 | 2006-06-23 02:03:35 -0700 | [diff] [blame] | 439 | swp_entry_t entry = pte_to_swp_entry(pte); |
| 440 | |
| 441 | swap_duplicate(entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 442 | /* make sure dst_mm is on swapoff's mmlist. */ |
| 443 | if (unlikely(list_empty(&dst_mm->mmlist))) { |
| 444 | spin_lock(&mmlist_lock); |
Hugh Dickins | f412ac0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 445 | if (list_empty(&dst_mm->mmlist)) |
| 446 | list_add(&dst_mm->mmlist, |
| 447 | &src_mm->mmlist); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 448 | spin_unlock(&mmlist_lock); |
| 449 | } |
Christoph Lameter | 0697212 | 2006-06-23 02:03:35 -0700 | [diff] [blame] | 450 | if (is_write_migration_entry(entry) && |
| 451 | is_cow_mapping(vm_flags)) { |
| 452 | /* |
| 453 | * COW mappings require pages in both parent |
| 454 | * and child to be set to read. |
| 455 | */ |
| 456 | make_migration_entry_read(&entry); |
| 457 | pte = swp_entry_to_pte(entry); |
| 458 | set_pte_at(src_mm, addr, src_pte, pte); |
| 459 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 460 | } |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 461 | goto out_set_pte; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 462 | } |
| 463 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | /* |
| 465 | * If it's a COW mapping, write protect it both |
| 466 | * in the parent and the child |
| 467 | */ |
Linus Torvalds | 6712117 | 2005-12-11 20:38:17 -0800 | [diff] [blame] | 468 | if (is_cow_mapping(vm_flags)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 469 | ptep_set_wrprotect(src_mm, addr, src_pte); |
| 470 | pte = *src_pte; |
| 471 | } |
| 472 | |
| 473 | /* |
| 474 | * If it's a shared mapping, mark it clean in |
| 475 | * the child |
| 476 | */ |
| 477 | if (vm_flags & VM_SHARED) |
| 478 | pte = pte_mkclean(pte); |
| 479 | pte = pte_mkold(pte); |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 480 | |
| 481 | page = vm_normal_page(vma, addr, pte); |
| 482 | if (page) { |
| 483 | get_page(page); |
| 484 | page_dup_rmap(page); |
| 485 | rss[!!PageAnon(page)]++; |
| 486 | } |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 487 | |
| 488 | out_set_pte: |
| 489 | set_pte_at(dst_mm, addr, dst_pte, pte); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | } |
| 491 | |
| 492 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 493 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, |
| 494 | unsigned long addr, unsigned long end) |
| 495 | { |
| 496 | pte_t *src_pte, *dst_pte; |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 497 | spinlock_t *src_ptl, *dst_ptl; |
Hugh Dickins | e040f21 | 2005-10-29 18:15:53 -0700 | [diff] [blame] | 498 | int progress = 0; |
Hugh Dickins | 8c10376 | 2005-10-29 18:16:13 -0700 | [diff] [blame] | 499 | int rss[2]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | |
| 501 | again: |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 502 | rss[1] = rss[0] = 0; |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 503 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 504 | if (!dst_pte) |
| 505 | return -ENOMEM; |
| 506 | src_pte = pte_offset_map_nested(src_pmd, addr); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 507 | src_ptl = pte_lockptr(src_mm, src_pmd); |
Ingo Molnar | f20dc5f | 2006-07-03 00:25:08 -0700 | [diff] [blame] | 508 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 510 | do { |
| 511 | /* |
| 512 | * We are holding two locks at this point - either of them |
| 513 | * could generate latencies in another task on another CPU. |
| 514 | */ |
Hugh Dickins | e040f21 | 2005-10-29 18:15:53 -0700 | [diff] [blame] | 515 | if (progress >= 32) { |
| 516 | progress = 0; |
| 517 | if (need_resched() || |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 518 | need_lockbreak(src_ptl) || |
| 519 | need_lockbreak(dst_ptl)) |
Hugh Dickins | e040f21 | 2005-10-29 18:15:53 -0700 | [diff] [blame] | 520 | break; |
| 521 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 522 | if (pte_none(*src_pte)) { |
| 523 | progress++; |
| 524 | continue; |
| 525 | } |
Hugh Dickins | 8c10376 | 2005-10-29 18:16:13 -0700 | [diff] [blame] | 526 | copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | progress += 8; |
| 528 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 530 | spin_unlock(src_ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 531 | pte_unmap_nested(src_pte - 1); |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 532 | add_mm_rss(dst_mm, rss[0], rss[1]); |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 533 | pte_unmap_unlock(dst_pte - 1, dst_ptl); |
| 534 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 535 | if (addr != end) |
| 536 | goto again; |
| 537 | return 0; |
| 538 | } |
| 539 | |
| 540 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 541 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, |
| 542 | unsigned long addr, unsigned long end) |
| 543 | { |
| 544 | pmd_t *src_pmd, *dst_pmd; |
| 545 | unsigned long next; |
| 546 | |
| 547 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); |
| 548 | if (!dst_pmd) |
| 549 | return -ENOMEM; |
| 550 | src_pmd = pmd_offset(src_pud, addr); |
| 551 | do { |
| 552 | next = pmd_addr_end(addr, end); |
| 553 | if (pmd_none_or_clear_bad(src_pmd)) |
| 554 | continue; |
| 555 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, |
| 556 | vma, addr, next)) |
| 557 | return -ENOMEM; |
| 558 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); |
| 559 | return 0; |
| 560 | } |
| 561 | |
| 562 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 563 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, |
| 564 | unsigned long addr, unsigned long end) |
| 565 | { |
| 566 | pud_t *src_pud, *dst_pud; |
| 567 | unsigned long next; |
| 568 | |
| 569 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); |
| 570 | if (!dst_pud) |
| 571 | return -ENOMEM; |
| 572 | src_pud = pud_offset(src_pgd, addr); |
| 573 | do { |
| 574 | next = pud_addr_end(addr, end); |
| 575 | if (pud_none_or_clear_bad(src_pud)) |
| 576 | continue; |
| 577 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, |
| 578 | vma, addr, next)) |
| 579 | return -ENOMEM; |
| 580 | } while (dst_pud++, src_pud++, addr = next, addr != end); |
| 581 | return 0; |
| 582 | } |
| 583 | |
| 584 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
| 585 | struct vm_area_struct *vma) |
| 586 | { |
| 587 | pgd_t *src_pgd, *dst_pgd; |
| 588 | unsigned long next; |
| 589 | unsigned long addr = vma->vm_start; |
| 590 | unsigned long end = vma->vm_end; |
| 591 | |
Nick Piggin | d992895 | 2005-08-28 16:49:11 +1000 | [diff] [blame] | 592 | /* |
| 593 | * Don't copy ptes where a page fault will fill them correctly. |
| 594 | * Fork becomes much lighter when there are big shared or private |
| 595 | * readonly mappings. The tradeoff is that copy_page_range is more |
| 596 | * efficient than faulting. |
| 597 | */ |
Linus Torvalds | 4d7672b | 2005-12-16 10:21:23 -0800 | [diff] [blame] | 598 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { |
Nick Piggin | d992895 | 2005-08-28 16:49:11 +1000 | [diff] [blame] | 599 | if (!vma->anon_vma) |
| 600 | return 0; |
| 601 | } |
| 602 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 603 | if (is_vm_hugetlb_page(vma)) |
| 604 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); |
| 605 | |
| 606 | dst_pgd = pgd_offset(dst_mm, addr); |
| 607 | src_pgd = pgd_offset(src_mm, addr); |
| 608 | do { |
| 609 | next = pgd_addr_end(addr, end); |
| 610 | if (pgd_none_or_clear_bad(src_pgd)) |
| 611 | continue; |
| 612 | if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
| 613 | vma, addr, next)) |
| 614 | return -ENOMEM; |
| 615 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
| 616 | return 0; |
| 617 | } |
| 618 | |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 619 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 620 | struct vm_area_struct *vma, pmd_t *pmd, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 621 | unsigned long addr, unsigned long end, |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 622 | long *zap_work, struct zap_details *details) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 623 | { |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 624 | struct mm_struct *mm = tlb->mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 625 | pte_t *pte; |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 626 | spinlock_t *ptl; |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 627 | int file_rss = 0; |
| 628 | int anon_rss = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 630 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 631 | do { |
| 632 | pte_t ptent = *pte; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 633 | if (pte_none(ptent)) { |
| 634 | (*zap_work)--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | continue; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 636 | } |
Hugh Dickins | 6f5e6b9 | 2006-03-16 23:04:09 -0800 | [diff] [blame] | 637 | |
| 638 | (*zap_work) -= PAGE_SIZE; |
| 639 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | if (pte_present(ptent)) { |
Hugh Dickins | ee498ed | 2005-11-21 21:32:18 -0800 | [diff] [blame] | 641 | struct page *page; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 642 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 643 | page = vm_normal_page(vma, addr, ptent); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 644 | if (unlikely(details) && page) { |
| 645 | /* |
| 646 | * unmap_shared_mapping_pages() wants to |
| 647 | * invalidate cache without truncating: |
| 648 | * unmap shared but keep private pages. |
| 649 | */ |
| 650 | if (details->check_mapping && |
| 651 | details->check_mapping != page->mapping) |
| 652 | continue; |
| 653 | /* |
| 654 | * Each page->index must be checked when |
| 655 | * invalidating or truncating nonlinear. |
| 656 | */ |
| 657 | if (details->nonlinear_vma && |
| 658 | (page->index < details->first_index || |
| 659 | page->index > details->last_index)) |
| 660 | continue; |
| 661 | } |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 662 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
Zachary Amsden | a600388 | 2005-09-03 15:55:04 -0700 | [diff] [blame] | 663 | tlb->fullmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 664 | tlb_remove_tlb_entry(tlb, pte, addr); |
| 665 | if (unlikely(!page)) |
| 666 | continue; |
| 667 | if (unlikely(details) && details->nonlinear_vma |
| 668 | && linear_page_index(details->nonlinear_vma, |
| 669 | addr) != page->index) |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 670 | set_pte_at(mm, addr, pte, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 671 | pgoff_to_pte(page->index)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 672 | if (PageAnon(page)) |
Hugh Dickins | 86d912f | 2005-10-29 18:16:14 -0700 | [diff] [blame] | 673 | anon_rss--; |
Hugh Dickins | 6237bcd | 2005-10-29 18:15:54 -0700 | [diff] [blame] | 674 | else { |
| 675 | if (pte_dirty(ptent)) |
| 676 | set_page_dirty(page); |
| 677 | if (pte_young(ptent)) |
| 678 | mark_page_accessed(page); |
Hugh Dickins | 86d912f | 2005-10-29 18:16:14 -0700 | [diff] [blame] | 679 | file_rss--; |
Hugh Dickins | 6237bcd | 2005-10-29 18:15:54 -0700 | [diff] [blame] | 680 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 681 | page_remove_rmap(page); |
| 682 | tlb_remove_page(tlb, page); |
| 683 | continue; |
| 684 | } |
| 685 | /* |
| 686 | * If details->check_mapping, we leave swap entries; |
| 687 | * if details->nonlinear_vma, we leave file entries. |
| 688 | */ |
| 689 | if (unlikely(details)) |
| 690 | continue; |
| 691 | if (!pte_file(ptent)) |
| 692 | free_swap_and_cache(pte_to_swp_entry(ptent)); |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 693 | pte_clear_full(mm, addr, pte, tlb->fullmm); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 694 | } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); |
Hugh Dickins | ae85976 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 695 | |
Hugh Dickins | 86d912f | 2005-10-29 18:16:14 -0700 | [diff] [blame] | 696 | add_mm_rss(mm, file_rss, anon_rss); |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 697 | pte_unmap_unlock(pte - 1, ptl); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 698 | |
| 699 | return addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 700 | } |
| 701 | |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 702 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 703 | struct vm_area_struct *vma, pud_t *pud, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 704 | unsigned long addr, unsigned long end, |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 705 | long *zap_work, struct zap_details *details) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 706 | { |
| 707 | pmd_t *pmd; |
| 708 | unsigned long next; |
| 709 | |
| 710 | pmd = pmd_offset(pud, addr); |
| 711 | do { |
| 712 | next = pmd_addr_end(addr, end); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 713 | if (pmd_none_or_clear_bad(pmd)) { |
| 714 | (*zap_work)--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 715 | continue; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 716 | } |
| 717 | next = zap_pte_range(tlb, vma, pmd, addr, next, |
| 718 | zap_work, details); |
| 719 | } while (pmd++, addr = next, (addr != end && *zap_work > 0)); |
| 720 | |
| 721 | return addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 722 | } |
| 723 | |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 724 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 725 | struct vm_area_struct *vma, pgd_t *pgd, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 726 | unsigned long addr, unsigned long end, |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 727 | long *zap_work, struct zap_details *details) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | { |
| 729 | pud_t *pud; |
| 730 | unsigned long next; |
| 731 | |
| 732 | pud = pud_offset(pgd, addr); |
| 733 | do { |
| 734 | next = pud_addr_end(addr, end); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 735 | if (pud_none_or_clear_bad(pud)) { |
| 736 | (*zap_work)--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 737 | continue; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 738 | } |
| 739 | next = zap_pmd_range(tlb, vma, pud, addr, next, |
| 740 | zap_work, details); |
| 741 | } while (pud++, addr = next, (addr != end && *zap_work > 0)); |
| 742 | |
| 743 | return addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 744 | } |
| 745 | |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 746 | static unsigned long unmap_page_range(struct mmu_gather *tlb, |
| 747 | struct vm_area_struct *vma, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 748 | unsigned long addr, unsigned long end, |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 749 | long *zap_work, struct zap_details *details) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 750 | { |
| 751 | pgd_t *pgd; |
| 752 | unsigned long next; |
| 753 | |
| 754 | if (details && !details->check_mapping && !details->nonlinear_vma) |
| 755 | details = NULL; |
| 756 | |
| 757 | BUG_ON(addr >= end); |
| 758 | tlb_start_vma(tlb, vma); |
| 759 | pgd = pgd_offset(vma->vm_mm, addr); |
| 760 | do { |
| 761 | next = pgd_addr_end(addr, end); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 762 | if (pgd_none_or_clear_bad(pgd)) { |
| 763 | (*zap_work)--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 764 | continue; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 765 | } |
| 766 | next = zap_pud_range(tlb, vma, pgd, addr, next, |
| 767 | zap_work, details); |
| 768 | } while (pgd++, addr = next, (addr != end && *zap_work > 0)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | tlb_end_vma(tlb, vma); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 770 | |
| 771 | return addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 772 | } |
| 773 | |
| 774 | #ifdef CONFIG_PREEMPT |
| 775 | # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) |
| 776 | #else |
| 777 | /* No preempt: go for improved straight-line efficiency */ |
| 778 | # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) |
| 779 | #endif |
| 780 | |
| 781 | /** |
| 782 | * unmap_vmas - unmap a range of memory covered by a list of vma's |
| 783 | * @tlbp: address of the caller's struct mmu_gather |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 784 | * @vma: the starting vma |
| 785 | * @start_addr: virtual address at which to start unmapping |
| 786 | * @end_addr: virtual address at which to end unmapping |
| 787 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here |
| 788 | * @details: details of nonlinear truncation or shared cache invalidation |
| 789 | * |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 790 | * Returns the end address of the unmapping (restart addr if interrupted). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 791 | * |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 792 | * Unmap all pages in the vma list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 793 | * |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 794 | * We aim to not hold locks for too long (for scheduling latency reasons). |
| 795 | * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 796 | * return the ending mmu_gather to the caller. |
| 797 | * |
| 798 | * Only addresses between `start' and `end' will be unmapped. |
| 799 | * |
| 800 | * The VMA list must be sorted in ascending virtual address order. |
| 801 | * |
| 802 | * unmap_vmas() assumes that the caller will flush the whole unmapped address |
| 803 | * range after unmap_vmas() returns. So the only responsibility here is to |
| 804 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() |
| 805 | * drops the lock and schedules. |
| 806 | */ |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 807 | unsigned long unmap_vmas(struct mmu_gather **tlbp, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 808 | struct vm_area_struct *vma, unsigned long start_addr, |
| 809 | unsigned long end_addr, unsigned long *nr_accounted, |
| 810 | struct zap_details *details) |
| 811 | { |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 812 | long zap_work = ZAP_BLOCK_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 813 | unsigned long tlb_start = 0; /* For tlb_finish_mmu */ |
| 814 | int tlb_start_valid = 0; |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 815 | unsigned long start = start_addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 816 | spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; |
Hugh Dickins | 4d6ddfa | 2005-10-29 18:16:02 -0700 | [diff] [blame] | 817 | int fullmm = (*tlbp)->fullmm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 818 | |
| 819 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 820 | unsigned long end; |
| 821 | |
| 822 | start = max(vma->vm_start, start_addr); |
| 823 | if (start >= vma->vm_end) |
| 824 | continue; |
| 825 | end = min(vma->vm_end, end_addr); |
| 826 | if (end <= vma->vm_start) |
| 827 | continue; |
| 828 | |
| 829 | if (vma->vm_flags & VM_ACCOUNT) |
| 830 | *nr_accounted += (end - start) >> PAGE_SHIFT; |
| 831 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 832 | while (start != end) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 833 | if (!tlb_start_valid) { |
| 834 | tlb_start = start; |
| 835 | tlb_start_valid = 1; |
| 836 | } |
| 837 | |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 838 | if (unlikely(is_vm_hugetlb_page(vma))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 839 | unmap_hugepage_range(vma, start, end); |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 840 | zap_work -= (end - start) / |
| 841 | (HPAGE_SIZE / PAGE_SIZE); |
| 842 | start = end; |
| 843 | } else |
| 844 | start = unmap_page_range(*tlbp, vma, |
| 845 | start, end, &zap_work, details); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 846 | |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 847 | if (zap_work > 0) { |
| 848 | BUG_ON(start != end); |
| 849 | break; |
| 850 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 851 | |
| 852 | tlb_finish_mmu(*tlbp, tlb_start, start); |
| 853 | |
| 854 | if (need_resched() || |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 855 | (i_mmap_lock && need_lockbreak(i_mmap_lock))) { |
| 856 | if (i_mmap_lock) { |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 857 | *tlbp = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 858 | goto out; |
| 859 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 860 | cond_resched(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 861 | } |
| 862 | |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 863 | *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 864 | tlb_start_valid = 0; |
Robin Holt | 51c6f66 | 2005-11-13 16:06:42 -0800 | [diff] [blame] | 865 | zap_work = ZAP_BLOCK_SIZE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 866 | } |
| 867 | } |
| 868 | out: |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 869 | return start; /* which is now the end (or restart) address */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | } |
| 871 | |
| 872 | /** |
| 873 | * zap_page_range - remove user pages in a given range |
| 874 | * @vma: vm_area_struct holding the applicable pages |
| 875 | * @address: starting address of pages to zap |
| 876 | * @size: number of bytes to zap |
| 877 | * @details: details of nonlinear truncation or shared cache invalidation |
| 878 | */ |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 879 | 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] | 880 | unsigned long size, struct zap_details *details) |
| 881 | { |
| 882 | struct mm_struct *mm = vma->vm_mm; |
| 883 | struct mmu_gather *tlb; |
| 884 | unsigned long end = address + size; |
| 885 | unsigned long nr_accounted = 0; |
| 886 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 887 | lru_add_drain(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 888 | tlb = tlb_gather_mmu(mm, 0); |
Hugh Dickins | 365e9c87 | 2005-10-29 18:16:18 -0700 | [diff] [blame] | 889 | update_hiwater_rss(mm); |
Hugh Dickins | 508034a | 2005-10-29 18:16:30 -0700 | [diff] [blame] | 890 | end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); |
| 891 | if (tlb) |
| 892 | tlb_finish_mmu(tlb, address, end); |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 893 | return end; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 894 | } |
| 895 | |
| 896 | /* |
| 897 | * Do a quick page-table lookup for a single page. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 898 | */ |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 899 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 900 | unsigned int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 901 | { |
| 902 | pgd_t *pgd; |
| 903 | pud_t *pud; |
| 904 | pmd_t *pmd; |
| 905 | pte_t *ptep, pte; |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 906 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | struct page *page; |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 908 | struct mm_struct *mm = vma->vm_mm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 909 | |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 910 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
| 911 | if (!IS_ERR(page)) { |
| 912 | BUG_ON(flags & FOLL_GET); |
| 913 | goto out; |
| 914 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 915 | |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 916 | page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 917 | pgd = pgd_offset(mm, address); |
| 918 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 919 | goto no_page_table; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 920 | |
| 921 | pud = pud_offset(pgd, address); |
| 922 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 923 | goto no_page_table; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 924 | |
| 925 | pmd = pmd_offset(pud, address); |
| 926 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 927 | goto no_page_table; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 928 | |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 929 | if (pmd_huge(*pmd)) { |
| 930 | BUG_ON(flags & FOLL_GET); |
| 931 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); |
| 932 | goto out; |
| 933 | } |
| 934 | |
| 935 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 936 | if (!ptep) |
| 937 | goto out; |
| 938 | |
| 939 | pte = *ptep; |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 940 | if (!pte_present(pte)) |
| 941 | goto unlock; |
| 942 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
| 943 | goto unlock; |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 944 | page = vm_normal_page(vma, address, pte); |
| 945 | if (unlikely(!page)) |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 946 | goto unlock; |
| 947 | |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 948 | if (flags & FOLL_GET) |
| 949 | get_page(page); |
| 950 | if (flags & FOLL_TOUCH) { |
| 951 | if ((flags & FOLL_WRITE) && |
| 952 | !pte_dirty(pte) && !PageDirty(page)) |
| 953 | set_page_dirty(page); |
| 954 | mark_page_accessed(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 955 | } |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 956 | unlock: |
| 957 | pte_unmap_unlock(ptep, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 958 | out: |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 959 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 960 | |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 961 | no_page_table: |
| 962 | /* |
| 963 | * When core dumping an enormous anonymous area that nobody |
| 964 | * has touched so far, we don't want to allocate page tables. |
| 965 | */ |
| 966 | if (flags & FOLL_ANON) { |
| 967 | page = ZERO_PAGE(address); |
| 968 | if (flags & FOLL_GET) |
| 969 | get_page(page); |
| 970 | BUG_ON(flags & FOLL_WRITE); |
| 971 | } |
| 972 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 973 | } |
| 974 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 975 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
| 976 | unsigned long start, int len, int write, int force, |
| 977 | struct page **pages, struct vm_area_struct **vmas) |
| 978 | { |
| 979 | int i; |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 980 | unsigned int vm_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 981 | |
| 982 | /* |
| 983 | * Require read or write permissions. |
| 984 | * If 'force' is set, we only require the "MAY" flags. |
| 985 | */ |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 986 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
| 987 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 988 | i = 0; |
| 989 | |
| 990 | do { |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 991 | struct vm_area_struct *vma; |
| 992 | unsigned int foll_flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 993 | |
| 994 | vma = find_extend_vma(mm, start); |
| 995 | if (!vma && in_gate_area(tsk, start)) { |
| 996 | unsigned long pg = start & PAGE_MASK; |
| 997 | struct vm_area_struct *gate_vma = get_gate_vma(tsk); |
| 998 | pgd_t *pgd; |
| 999 | pud_t *pud; |
| 1000 | pmd_t *pmd; |
| 1001 | pte_t *pte; |
| 1002 | if (write) /* user gate pages are read-only */ |
| 1003 | return i ? : -EFAULT; |
| 1004 | if (pg > TASK_SIZE) |
| 1005 | pgd = pgd_offset_k(pg); |
| 1006 | else |
| 1007 | pgd = pgd_offset_gate(mm, pg); |
| 1008 | BUG_ON(pgd_none(*pgd)); |
| 1009 | pud = pud_offset(pgd, pg); |
| 1010 | BUG_ON(pud_none(*pud)); |
| 1011 | pmd = pmd_offset(pud, pg); |
Hugh Dickins | 690dbe1 | 2005-08-01 21:11:42 -0700 | [diff] [blame] | 1012 | if (pmd_none(*pmd)) |
| 1013 | return i ? : -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1014 | pte = pte_offset_map(pmd, pg); |
Hugh Dickins | 690dbe1 | 2005-08-01 21:11:42 -0700 | [diff] [blame] | 1015 | if (pte_none(*pte)) { |
| 1016 | pte_unmap(pte); |
| 1017 | return i ? : -EFAULT; |
| 1018 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1019 | if (pages) { |
Nick Piggin | fa2a455 | 2005-11-29 18:43:17 +1100 | [diff] [blame] | 1020 | struct page *page = vm_normal_page(gate_vma, start, *pte); |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1021 | pages[i] = page; |
| 1022 | if (page) |
| 1023 | get_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1024 | } |
| 1025 | pte_unmap(pte); |
| 1026 | if (vmas) |
| 1027 | vmas[i] = gate_vma; |
| 1028 | i++; |
| 1029 | start += PAGE_SIZE; |
| 1030 | len--; |
| 1031 | continue; |
| 1032 | } |
| 1033 | |
Linus Torvalds | 1ff8038 | 2005-12-12 16:24:33 -0800 | [diff] [blame] | 1034 | if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 1035 | || !(vm_flags & vma->vm_flags)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1036 | return i ? : -EFAULT; |
| 1037 | |
| 1038 | if (is_vm_hugetlb_page(vma)) { |
| 1039 | i = follow_hugetlb_page(mm, vma, pages, vmas, |
| 1040 | &start, &len, i); |
| 1041 | continue; |
| 1042 | } |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 1043 | |
| 1044 | foll_flags = FOLL_TOUCH; |
| 1045 | if (pages) |
| 1046 | foll_flags |= FOLL_GET; |
| 1047 | if (!write && !(vma->vm_flags & VM_LOCKED) && |
| 1048 | (!vma->vm_ops || !vma->vm_ops->nopage)) |
| 1049 | foll_flags |= FOLL_ANON; |
| 1050 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | do { |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1052 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1053 | |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 1054 | if (write) |
| 1055 | foll_flags |= FOLL_WRITE; |
| 1056 | |
| 1057 | cond_resched(); |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1058 | while (!(page = follow_page(vma, start, foll_flags))) { |
Linus Torvalds | a68d2eb | 2005-08-03 10:07:09 -0700 | [diff] [blame] | 1059 | int ret; |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 1060 | ret = __handle_mm_fault(mm, vma, start, |
| 1061 | foll_flags & FOLL_WRITE); |
Linus Torvalds | a68d2eb | 2005-08-03 10:07:09 -0700 | [diff] [blame] | 1062 | /* |
| 1063 | * The VM_FAULT_WRITE bit tells us that do_wp_page has |
| 1064 | * broken COW when necessary, even if maybe_mkwrite |
| 1065 | * decided not to set pte_write. We can thus safely do |
| 1066 | * subsequent page lookups as if they were reads. |
| 1067 | */ |
| 1068 | if (ret & VM_FAULT_WRITE) |
Hugh Dickins | deceb6c | 2005-10-29 18:16:33 -0700 | [diff] [blame] | 1069 | foll_flags &= ~FOLL_WRITE; |
Linus Torvalds | a68d2eb | 2005-08-03 10:07:09 -0700 | [diff] [blame] | 1070 | |
| 1071 | switch (ret & ~VM_FAULT_WRITE) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | case VM_FAULT_MINOR: |
| 1073 | tsk->min_flt++; |
| 1074 | break; |
| 1075 | case VM_FAULT_MAJOR: |
| 1076 | tsk->maj_flt++; |
| 1077 | break; |
| 1078 | case VM_FAULT_SIGBUS: |
| 1079 | return i ? i : -EFAULT; |
| 1080 | case VM_FAULT_OOM: |
| 1081 | return i ? i : -ENOMEM; |
| 1082 | default: |
| 1083 | BUG(); |
| 1084 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1085 | } |
| 1086 | if (pages) { |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1087 | pages[i] = page; |
James Bottomley | 03beb07 | 2006-03-26 01:36:57 -0800 | [diff] [blame] | 1088 | |
| 1089 | flush_anon_page(page, start); |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1090 | flush_dcache_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1091 | } |
| 1092 | if (vmas) |
| 1093 | vmas[i] = vma; |
| 1094 | i++; |
| 1095 | start += PAGE_SIZE; |
| 1096 | len--; |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1097 | } while (len && start < vma->vm_end); |
Hugh Dickins | 08ef472 | 2005-06-21 17:15:10 -0700 | [diff] [blame] | 1098 | } while (len); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | return i; |
| 1100 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1101 | EXPORT_SYMBOL(get_user_pages); |
| 1102 | |
| 1103 | static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd, |
| 1104 | unsigned long addr, unsigned long end, pgprot_t prot) |
| 1105 | { |
| 1106 | pte_t *pte; |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 1107 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1108 | |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 1109 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1110 | if (!pte) |
| 1111 | return -ENOMEM; |
| 1112 | do { |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 1113 | struct page *page = ZERO_PAGE(addr); |
| 1114 | pte_t zero_pte = pte_wrprotect(mk_pte(page, prot)); |
| 1115 | page_cache_get(page); |
| 1116 | page_add_file_rmap(page); |
| 1117 | inc_mm_counter(mm, file_rss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1118 | BUG_ON(!pte_none(*pte)); |
| 1119 | set_pte_at(mm, addr, pte, zero_pte); |
| 1120 | } while (pte++, addr += PAGE_SIZE, addr != end); |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 1121 | pte_unmap_unlock(pte - 1, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1122 | return 0; |
| 1123 | } |
| 1124 | |
| 1125 | static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud, |
| 1126 | unsigned long addr, unsigned long end, pgprot_t prot) |
| 1127 | { |
| 1128 | pmd_t *pmd; |
| 1129 | unsigned long next; |
| 1130 | |
| 1131 | pmd = pmd_alloc(mm, pud, addr); |
| 1132 | if (!pmd) |
| 1133 | return -ENOMEM; |
| 1134 | do { |
| 1135 | next = pmd_addr_end(addr, end); |
| 1136 | if (zeromap_pte_range(mm, pmd, addr, next, prot)) |
| 1137 | return -ENOMEM; |
| 1138 | } while (pmd++, addr = next, addr != end); |
| 1139 | return 0; |
| 1140 | } |
| 1141 | |
| 1142 | static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd, |
| 1143 | unsigned long addr, unsigned long end, pgprot_t prot) |
| 1144 | { |
| 1145 | pud_t *pud; |
| 1146 | unsigned long next; |
| 1147 | |
| 1148 | pud = pud_alloc(mm, pgd, addr); |
| 1149 | if (!pud) |
| 1150 | return -ENOMEM; |
| 1151 | do { |
| 1152 | next = pud_addr_end(addr, end); |
| 1153 | if (zeromap_pmd_range(mm, pud, addr, next, prot)) |
| 1154 | return -ENOMEM; |
| 1155 | } while (pud++, addr = next, addr != end); |
| 1156 | return 0; |
| 1157 | } |
| 1158 | |
| 1159 | int zeromap_page_range(struct vm_area_struct *vma, |
| 1160 | unsigned long addr, unsigned long size, pgprot_t prot) |
| 1161 | { |
| 1162 | pgd_t *pgd; |
| 1163 | unsigned long next; |
| 1164 | unsigned long end = addr + size; |
| 1165 | struct mm_struct *mm = vma->vm_mm; |
| 1166 | int err; |
| 1167 | |
| 1168 | BUG_ON(addr >= end); |
| 1169 | pgd = pgd_offset(mm, addr); |
| 1170 | flush_cache_range(vma, addr, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1171 | do { |
| 1172 | next = pgd_addr_end(addr, end); |
| 1173 | err = zeromap_pud_range(mm, pgd, addr, next, prot); |
| 1174 | if (err) |
| 1175 | break; |
| 1176 | } while (pgd++, addr = next, addr != end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1177 | return err; |
| 1178 | } |
| 1179 | |
Trond Myklebust | 49c91fb | 2005-11-29 19:27:22 -0500 | [diff] [blame] | 1180 | pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl) |
Linus Torvalds | c9cfcdd | 2005-11-29 14:03:14 -0800 | [diff] [blame] | 1181 | { |
| 1182 | pgd_t * pgd = pgd_offset(mm, addr); |
| 1183 | pud_t * pud = pud_alloc(mm, pgd, addr); |
| 1184 | if (pud) { |
Trond Myklebust | 49c91fb | 2005-11-29 19:27:22 -0500 | [diff] [blame] | 1185 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
Linus Torvalds | c9cfcdd | 2005-11-29 14:03:14 -0800 | [diff] [blame] | 1186 | if (pmd) |
| 1187 | return pte_alloc_map_lock(mm, pmd, addr, ptl); |
| 1188 | } |
| 1189 | return NULL; |
| 1190 | } |
| 1191 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1192 | /* |
Linus Torvalds | 238f58d | 2005-11-29 13:01:56 -0800 | [diff] [blame] | 1193 | * This is the old fallback for page remapping. |
| 1194 | * |
| 1195 | * For historical reasons, it only allows reserved pages. Only |
| 1196 | * old drivers should use this, and they needed to mark their |
| 1197 | * pages reserved for the old functions anyway. |
| 1198 | */ |
| 1199 | static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot) |
| 1200 | { |
| 1201 | int retval; |
Linus Torvalds | c9cfcdd | 2005-11-29 14:03:14 -0800 | [diff] [blame] | 1202 | pte_t *pte; |
Linus Torvalds | 238f58d | 2005-11-29 13:01:56 -0800 | [diff] [blame] | 1203 | spinlock_t *ptl; |
| 1204 | |
| 1205 | retval = -EINVAL; |
Linus Torvalds | a145dd4 | 2005-11-30 09:35:19 -0800 | [diff] [blame] | 1206 | if (PageAnon(page)) |
Linus Torvalds | 238f58d | 2005-11-29 13:01:56 -0800 | [diff] [blame] | 1207 | goto out; |
| 1208 | retval = -ENOMEM; |
| 1209 | flush_dcache_page(page); |
Linus Torvalds | c9cfcdd | 2005-11-29 14:03:14 -0800 | [diff] [blame] | 1210 | pte = get_locked_pte(mm, addr, &ptl); |
Linus Torvalds | 238f58d | 2005-11-29 13:01:56 -0800 | [diff] [blame] | 1211 | if (!pte) |
| 1212 | goto out; |
| 1213 | retval = -EBUSY; |
| 1214 | if (!pte_none(*pte)) |
| 1215 | goto out_unlock; |
| 1216 | |
| 1217 | /* Ok, finally just insert the thing.. */ |
| 1218 | get_page(page); |
| 1219 | inc_mm_counter(mm, file_rss); |
| 1220 | page_add_file_rmap(page); |
| 1221 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); |
| 1222 | |
| 1223 | retval = 0; |
| 1224 | out_unlock: |
| 1225 | pte_unmap_unlock(pte, ptl); |
| 1226 | out: |
| 1227 | return retval; |
| 1228 | } |
| 1229 | |
Rolf Eike Beer | bfa5bf6 | 2006-09-25 23:31:22 -0700 | [diff] [blame] | 1230 | /** |
| 1231 | * vm_insert_page - insert single page into user vma |
| 1232 | * @vma: user vma to map to |
| 1233 | * @addr: target user address of this page |
| 1234 | * @page: source kernel page |
| 1235 | * |
Linus Torvalds | a145dd4 | 2005-11-30 09:35:19 -0800 | [diff] [blame] | 1236 | * This allows drivers to insert individual pages they've allocated |
| 1237 | * into a user vma. |
| 1238 | * |
| 1239 | * The page has to be a nice clean _individual_ kernel allocation. |
| 1240 | * If you allocate a compound page, you need to have marked it as |
| 1241 | * such (__GFP_COMP), or manually just split the page up yourself |
Nick Piggin | 8dfcc9b | 2006-03-22 00:08:05 -0800 | [diff] [blame] | 1242 | * (see split_page()). |
Linus Torvalds | a145dd4 | 2005-11-30 09:35:19 -0800 | [diff] [blame] | 1243 | * |
| 1244 | * NOTE! Traditionally this was done with "remap_pfn_range()" which |
| 1245 | * took an arbitrary page protection parameter. This doesn't allow |
| 1246 | * that. Your vma protection will have to be set up correctly, which |
| 1247 | * means that if you want a shared writable mapping, you'd better |
| 1248 | * ask for a shared writable mapping! |
| 1249 | * |
| 1250 | * The page does not need to be reserved. |
| 1251 | */ |
| 1252 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) |
| 1253 | { |
| 1254 | if (addr < vma->vm_start || addr >= vma->vm_end) |
| 1255 | return -EFAULT; |
| 1256 | if (!page_count(page)) |
| 1257 | return -EINVAL; |
Linus Torvalds | 4d7672b | 2005-12-16 10:21:23 -0800 | [diff] [blame] | 1258 | vma->vm_flags |= VM_INSERTPAGE; |
Linus Torvalds | a145dd4 | 2005-11-30 09:35:19 -0800 | [diff] [blame] | 1259 | return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot); |
| 1260 | } |
Linus Torvalds | e3c3374 | 2005-12-03 20:48:11 -0800 | [diff] [blame] | 1261 | EXPORT_SYMBOL(vm_insert_page); |
Linus Torvalds | a145dd4 | 2005-11-30 09:35:19 -0800 | [diff] [blame] | 1262 | |
| 1263 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1264 | * maps a range of physical memory into the requested pages. the old |
| 1265 | * mappings are removed. any references to nonexistent pages results |
| 1266 | * in null mappings (currently treated as "copy-on-access") |
| 1267 | */ |
| 1268 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, |
| 1269 | unsigned long addr, unsigned long end, |
| 1270 | unsigned long pfn, pgprot_t prot) |
| 1271 | { |
| 1272 | pte_t *pte; |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 1273 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1274 | |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 1275 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1276 | if (!pte) |
| 1277 | return -ENOMEM; |
| 1278 | do { |
| 1279 | BUG_ON(!pte_none(*pte)); |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 1280 | set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1281 | pfn++; |
| 1282 | } while (pte++, addr += PAGE_SIZE, addr != end); |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 1283 | pte_unmap_unlock(pte - 1, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1284 | return 0; |
| 1285 | } |
| 1286 | |
| 1287 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, |
| 1288 | unsigned long addr, unsigned long end, |
| 1289 | unsigned long pfn, pgprot_t prot) |
| 1290 | { |
| 1291 | pmd_t *pmd; |
| 1292 | unsigned long next; |
| 1293 | |
| 1294 | pfn -= addr >> PAGE_SHIFT; |
| 1295 | pmd = pmd_alloc(mm, pud, addr); |
| 1296 | if (!pmd) |
| 1297 | return -ENOMEM; |
| 1298 | do { |
| 1299 | next = pmd_addr_end(addr, end); |
| 1300 | if (remap_pte_range(mm, pmd, addr, next, |
| 1301 | pfn + (addr >> PAGE_SHIFT), prot)) |
| 1302 | return -ENOMEM; |
| 1303 | } while (pmd++, addr = next, addr != end); |
| 1304 | return 0; |
| 1305 | } |
| 1306 | |
| 1307 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, |
| 1308 | unsigned long addr, unsigned long end, |
| 1309 | unsigned long pfn, pgprot_t prot) |
| 1310 | { |
| 1311 | pud_t *pud; |
| 1312 | unsigned long next; |
| 1313 | |
| 1314 | pfn -= addr >> PAGE_SHIFT; |
| 1315 | pud = pud_alloc(mm, pgd, addr); |
| 1316 | if (!pud) |
| 1317 | return -ENOMEM; |
| 1318 | do { |
| 1319 | next = pud_addr_end(addr, end); |
| 1320 | if (remap_pmd_range(mm, pud, addr, next, |
| 1321 | pfn + (addr >> PAGE_SHIFT), prot)) |
| 1322 | return -ENOMEM; |
| 1323 | } while (pud++, addr = next, addr != end); |
| 1324 | return 0; |
| 1325 | } |
| 1326 | |
Rolf Eike Beer | bfa5bf6 | 2006-09-25 23:31:22 -0700 | [diff] [blame] | 1327 | /** |
| 1328 | * remap_pfn_range - remap kernel memory to userspace |
| 1329 | * @vma: user vma to map to |
| 1330 | * @addr: target user address to start at |
| 1331 | * @pfn: physical address of kernel memory |
| 1332 | * @size: size of map area |
| 1333 | * @prot: page protection flags for this mapping |
| 1334 | * |
| 1335 | * Note: this is only safe if the mm semaphore is held when called. |
| 1336 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1337 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
| 1338 | unsigned long pfn, unsigned long size, pgprot_t prot) |
| 1339 | { |
| 1340 | pgd_t *pgd; |
| 1341 | unsigned long next; |
Hugh Dickins | 2d15cab | 2005-06-25 14:54:33 -0700 | [diff] [blame] | 1342 | unsigned long end = addr + PAGE_ALIGN(size); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1343 | struct mm_struct *mm = vma->vm_mm; |
| 1344 | int err; |
| 1345 | |
| 1346 | /* |
| 1347 | * Physically remapped pages are special. Tell the |
| 1348 | * rest of the world about it: |
| 1349 | * VM_IO tells people not to look at these pages |
| 1350 | * (accesses can have side effects). |
Hugh Dickins | 0b14c17 | 2005-11-21 21:32:15 -0800 | [diff] [blame] | 1351 | * VM_RESERVED is specified all over the place, because |
| 1352 | * in 2.4 it kept swapout's vma scan off this vma; but |
| 1353 | * in 2.6 the LRU scan won't even find its pages, so this |
| 1354 | * flag means no more than count its pages in reserved_vm, |
| 1355 | * and omit it from core dump, even when VM_IO turned off. |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1356 | * VM_PFNMAP tells the core MM that the base pages are just |
| 1357 | * raw PFN mappings, and do not have a "struct page" associated |
| 1358 | * with them. |
Linus Torvalds | fb155c1 | 2005-12-11 19:46:02 -0800 | [diff] [blame] | 1359 | * |
| 1360 | * There's a horrible special case to handle copy-on-write |
| 1361 | * behaviour that some programs depend on. We mark the "original" |
| 1362 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1363 | */ |
Linus Torvalds | 6712117 | 2005-12-11 20:38:17 -0800 | [diff] [blame] | 1364 | if (is_cow_mapping(vma->vm_flags)) { |
Linus Torvalds | fb155c1 | 2005-12-11 19:46:02 -0800 | [diff] [blame] | 1365 | if (addr != vma->vm_start || end != vma->vm_end) |
Linus Torvalds | 7fc7e2e | 2005-12-11 19:57:52 -0800 | [diff] [blame] | 1366 | return -EINVAL; |
Linus Torvalds | fb155c1 | 2005-12-11 19:46:02 -0800 | [diff] [blame] | 1367 | vma->vm_pgoff = pfn; |
| 1368 | } |
| 1369 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1370 | vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1371 | |
| 1372 | BUG_ON(addr >= end); |
| 1373 | pfn -= addr >> PAGE_SHIFT; |
| 1374 | pgd = pgd_offset(mm, addr); |
| 1375 | flush_cache_range(vma, addr, end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1376 | do { |
| 1377 | next = pgd_addr_end(addr, end); |
| 1378 | err = remap_pud_range(mm, pgd, addr, next, |
| 1379 | pfn + (addr >> PAGE_SHIFT), prot); |
| 1380 | if (err) |
| 1381 | break; |
| 1382 | } while (pgd++, addr = next, addr != end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1383 | return err; |
| 1384 | } |
| 1385 | EXPORT_SYMBOL(remap_pfn_range); |
| 1386 | |
| 1387 | /* |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1388 | * handle_pte_fault chooses page fault handler according to an entry |
| 1389 | * which was read non-atomically. Before making any commitment, on |
| 1390 | * those architectures or configurations (e.g. i386 with PAE) which |
| 1391 | * might give a mix of unmatched parts, do_swap_page and do_file_page |
| 1392 | * must check under lock before unmapping the pte and proceeding |
| 1393 | * (but do_wp_page is only called after already making such a check; |
| 1394 | * and do_anonymous_page and do_no_page can safely check later on). |
| 1395 | */ |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 1396 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1397 | pte_t *page_table, pte_t orig_pte) |
| 1398 | { |
| 1399 | int same = 1; |
| 1400 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) |
| 1401 | if (sizeof(pte_t) > sizeof(unsigned long)) { |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 1402 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
| 1403 | spin_lock(ptl); |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1404 | same = pte_same(*page_table, orig_pte); |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 1405 | spin_unlock(ptl); |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1406 | } |
| 1407 | #endif |
| 1408 | pte_unmap(page_table); |
| 1409 | return same; |
| 1410 | } |
| 1411 | |
| 1412 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1413 | * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when |
| 1414 | * servicing faults for write access. In the normal case, do always want |
| 1415 | * pte_mkwrite. But get_user_pages can cause write faults for mappings |
| 1416 | * that do not have writing enabled, when used by access_process_vm. |
| 1417 | */ |
| 1418 | static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) |
| 1419 | { |
| 1420 | if (likely(vma->vm_flags & VM_WRITE)) |
| 1421 | pte = pte_mkwrite(pte); |
| 1422 | return pte; |
| 1423 | } |
| 1424 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1425 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va) |
| 1426 | { |
| 1427 | /* |
| 1428 | * If the source page was a PFN mapping, we don't have |
| 1429 | * a "struct page" for it. We do a best-effort copy by |
| 1430 | * just copying from the original user address. If that |
| 1431 | * fails, we just zero-fill it. Live with it. |
| 1432 | */ |
| 1433 | if (unlikely(!src)) { |
| 1434 | void *kaddr = kmap_atomic(dst, KM_USER0); |
Linus Torvalds | 5d2a2db | 2005-11-29 14:07:55 -0800 | [diff] [blame] | 1435 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
| 1436 | |
| 1437 | /* |
| 1438 | * This really shouldn't fail, because the page is there |
| 1439 | * in the page tables. But it might just be unreadable, |
| 1440 | * in which case we just give up and fill the result with |
| 1441 | * zeroes. |
| 1442 | */ |
| 1443 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1444 | memset(kaddr, 0, PAGE_SIZE); |
| 1445 | kunmap_atomic(kaddr, KM_USER0); |
| 1446 | return; |
| 1447 | |
| 1448 | } |
| 1449 | copy_user_highpage(dst, src, va); |
| 1450 | } |
| 1451 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1452 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1453 | * This routine handles present pages, when users try to write |
| 1454 | * to a shared page. It is done by copying the page to a new address |
| 1455 | * and decrementing the shared-page counter for the old page. |
| 1456 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1457 | * Note that this routine assumes that the protection checks have been |
| 1458 | * done by the caller (the low-level page fault routine in most cases). |
| 1459 | * Thus we can safely just mark it writable once we've done any necessary |
| 1460 | * COW. |
| 1461 | * |
| 1462 | * We also mark the page dirty at this point even though the page will |
| 1463 | * change only once the write actually happens. This avoids a few races, |
| 1464 | * and potentially makes it more efficient. |
| 1465 | * |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1466 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 1467 | * but allow concurrent faults), with pte both mapped and locked. |
| 1468 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1469 | */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1470 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1471 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1472 | spinlock_t *ptl, pte_t orig_pte) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1473 | { |
Hugh Dickins | e5bbe4d | 2005-11-29 16:54:51 +0000 | [diff] [blame] | 1474 | struct page *old_page, *new_page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1475 | pte_t entry; |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1476 | int reuse = 0, ret = VM_FAULT_MINOR; |
| 1477 | struct page *dirty_page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1478 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1479 | old_page = vm_normal_page(vma, address, orig_pte); |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 1480 | if (!old_page) |
| 1481 | goto gotten; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1482 | |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1483 | /* |
Peter Zijlstra | ee6a645 | 2006-09-25 23:31:00 -0700 | [diff] [blame] | 1484 | * Take out anonymous pages first, anonymous shared vmas are |
| 1485 | * not dirty accountable. |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1486 | */ |
Peter Zijlstra | ee6a645 | 2006-09-25 23:31:00 -0700 | [diff] [blame] | 1487 | if (PageAnon(old_page)) { |
| 1488 | if (!TestSetPageLocked(old_page)) { |
| 1489 | reuse = can_share_swap_page(old_page); |
| 1490 | unlock_page(old_page); |
| 1491 | } |
| 1492 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1493 | (VM_WRITE|VM_SHARED))) { |
Peter Zijlstra | ee6a645 | 2006-09-25 23:31:00 -0700 | [diff] [blame] | 1494 | /* |
| 1495 | * Only catch write-faults on shared writable pages, |
| 1496 | * read-only shared pages can get COWed by |
| 1497 | * get_user_pages(.write=1, .force=1). |
| 1498 | */ |
David Howells | 9637a5e | 2006-06-23 02:03:43 -0700 | [diff] [blame] | 1499 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
| 1500 | /* |
| 1501 | * Notify the address space that the page is about to |
| 1502 | * become writable so that it can prohibit this or wait |
| 1503 | * for the page to get into an appropriate state. |
| 1504 | * |
| 1505 | * We do this without the lock held, so that it can |
| 1506 | * sleep if it needs to. |
| 1507 | */ |
| 1508 | page_cache_get(old_page); |
| 1509 | pte_unmap_unlock(page_table, ptl); |
| 1510 | |
| 1511 | if (vma->vm_ops->page_mkwrite(vma, old_page) < 0) |
| 1512 | goto unwritable_page; |
| 1513 | |
| 1514 | page_cache_release(old_page); |
| 1515 | |
| 1516 | /* |
| 1517 | * Since we dropped the lock we need to revalidate |
| 1518 | * the PTE as someone else may have changed it. If |
| 1519 | * they did, we just return, as we can count on the |
| 1520 | * MMU to tell us if they didn't also make it writable. |
| 1521 | */ |
| 1522 | page_table = pte_offset_map_lock(mm, pmd, address, |
| 1523 | &ptl); |
| 1524 | if (!pte_same(*page_table, orig_pte)) |
| 1525 | goto unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1526 | } |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1527 | dirty_page = old_page; |
| 1528 | get_page(dirty_page); |
David Howells | 9637a5e | 2006-06-23 02:03:43 -0700 | [diff] [blame] | 1529 | reuse = 1; |
David Howells | 9637a5e | 2006-06-23 02:03:43 -0700 | [diff] [blame] | 1530 | } |
| 1531 | |
| 1532 | if (reuse) { |
| 1533 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
| 1534 | entry = pte_mkyoung(orig_pte); |
| 1535 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
| 1536 | ptep_set_access_flags(vma, address, page_table, entry, 1); |
| 1537 | update_mmu_cache(vma, address, entry); |
| 1538 | lazy_mmu_prot_update(entry); |
| 1539 | ret |= VM_FAULT_WRITE; |
| 1540 | goto unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1541 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1542 | |
| 1543 | /* |
| 1544 | * Ok, we need to copy. Oh, well.. |
| 1545 | */ |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 1546 | page_cache_get(old_page); |
Hugh Dickins | 920fc35 | 2005-11-21 21:32:17 -0800 | [diff] [blame] | 1547 | gotten: |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1548 | pte_unmap_unlock(page_table, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1549 | |
| 1550 | if (unlikely(anon_vma_prepare(vma))) |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1551 | goto oom; |
Hugh Dickins | e5bbe4d | 2005-11-29 16:54:51 +0000 | [diff] [blame] | 1552 | if (old_page == ZERO_PAGE(address)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1553 | new_page = alloc_zeroed_user_highpage(vma, address); |
| 1554 | if (!new_page) |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1555 | goto oom; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1556 | } else { |
| 1557 | new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); |
| 1558 | if (!new_page) |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1559 | goto oom; |
Hugh Dickins | e5bbe4d | 2005-11-29 16:54:51 +0000 | [diff] [blame] | 1560 | cow_user_page(new_page, old_page, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1561 | } |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1562 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1563 | /* |
| 1564 | * Re-check the pte - we dropped the lock |
| 1565 | */ |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1566 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1567 | if (likely(pte_same(*page_table, orig_pte))) { |
Hugh Dickins | 920fc35 | 2005-11-21 21:32:17 -0800 | [diff] [blame] | 1568 | if (old_page) { |
| 1569 | page_remove_rmap(old_page); |
| 1570 | if (!PageAnon(old_page)) { |
| 1571 | dec_mm_counter(mm, file_rss); |
| 1572 | inc_mm_counter(mm, anon_rss); |
| 1573 | } |
| 1574 | } else |
Hugh Dickins | 4294621 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 1575 | inc_mm_counter(mm, anon_rss); |
Ben Collins | eca3513 | 2005-11-29 11:45:26 -0800 | [diff] [blame] | 1576 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1577 | entry = mk_pte(new_page, vma->vm_page_prot); |
| 1578 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
Anil Keshavamurthy | c38c8db | 2006-07-14 00:23:57 -0700 | [diff] [blame] | 1579 | lazy_mmu_prot_update(entry); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1580 | ptep_establish(vma, address, page_table, entry); |
| 1581 | update_mmu_cache(vma, address, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1582 | lru_cache_add_active(new_page); |
Nick Piggin | 9617d95 | 2006-01-06 00:11:12 -0800 | [diff] [blame] | 1583 | page_add_new_anon_rmap(new_page, vma, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1584 | |
| 1585 | /* Free the old page.. */ |
| 1586 | new_page = old_page; |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1587 | ret |= VM_FAULT_WRITE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1588 | } |
Hugh Dickins | 920fc35 | 2005-11-21 21:32:17 -0800 | [diff] [blame] | 1589 | if (new_page) |
| 1590 | page_cache_release(new_page); |
| 1591 | if (old_page) |
| 1592 | page_cache_release(old_page); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1593 | unlock: |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1594 | pte_unmap_unlock(page_table, ptl); |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1595 | if (dirty_page) { |
Peter Zijlstra | edc79b2 | 2006-09-25 23:30:58 -0700 | [diff] [blame] | 1596 | set_page_dirty_balance(dirty_page); |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 1597 | put_page(dirty_page); |
| 1598 | } |
Nick Piggin | f33ea7f | 2005-08-03 20:24:01 +1000 | [diff] [blame] | 1599 | return ret; |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1600 | oom: |
Hugh Dickins | 920fc35 | 2005-11-21 21:32:17 -0800 | [diff] [blame] | 1601 | if (old_page) |
| 1602 | page_cache_release(old_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1603 | return VM_FAULT_OOM; |
David Howells | 9637a5e | 2006-06-23 02:03:43 -0700 | [diff] [blame] | 1604 | |
| 1605 | unwritable_page: |
| 1606 | page_cache_release(old_page); |
| 1607 | return VM_FAULT_SIGBUS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1608 | } |
| 1609 | |
| 1610 | /* |
| 1611 | * Helper functions for unmap_mapping_range(). |
| 1612 | * |
| 1613 | * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ |
| 1614 | * |
| 1615 | * We have to restart searching the prio_tree whenever we drop the lock, |
| 1616 | * since the iterator is only valid while the lock is held, and anyway |
| 1617 | * a later vma might be split and reinserted earlier while lock dropped. |
| 1618 | * |
| 1619 | * The list of nonlinear vmas could be handled more efficiently, using |
| 1620 | * a placeholder, but handle it in the same way until a need is shown. |
| 1621 | * It is important to search the prio_tree before nonlinear list: a vma |
| 1622 | * may become nonlinear and be shifted from prio_tree to nonlinear list |
| 1623 | * while the lock is dropped; but never shifted from list to prio_tree. |
| 1624 | * |
| 1625 | * In order to make forward progress despite restarting the search, |
| 1626 | * vm_truncate_count is used to mark a vma as now dealt with, so we can |
| 1627 | * quickly skip it next time around. Since the prio_tree search only |
| 1628 | * shows us those vmas affected by unmapping the range in question, we |
| 1629 | * can't efficiently keep all vmas in step with mapping->truncate_count: |
| 1630 | * so instead reset them all whenever it wraps back to 0 (then go to 1). |
| 1631 | * mapping->truncate_count and vma->vm_truncate_count are protected by |
| 1632 | * i_mmap_lock. |
| 1633 | * |
| 1634 | * In order to make forward progress despite repeatedly restarting some |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1635 | * 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] | 1636 | * and restart from that address when we reach that vma again. It might |
| 1637 | * have been split or merged, shrunk or extended, but never shifted: so |
| 1638 | * restart_addr remains valid so long as it remains in the vma's range. |
| 1639 | * unmap_mapping_range forces truncate_count to leap over page-aligned |
| 1640 | * values so we can save vma's restart_addr in its truncate_count field. |
| 1641 | */ |
| 1642 | #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) |
| 1643 | |
| 1644 | static void reset_vma_truncate_counts(struct address_space *mapping) |
| 1645 | { |
| 1646 | struct vm_area_struct *vma; |
| 1647 | struct prio_tree_iter iter; |
| 1648 | |
| 1649 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) |
| 1650 | vma->vm_truncate_count = 0; |
| 1651 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) |
| 1652 | vma->vm_truncate_count = 0; |
| 1653 | } |
| 1654 | |
| 1655 | static int unmap_mapping_range_vma(struct vm_area_struct *vma, |
| 1656 | unsigned long start_addr, unsigned long end_addr, |
| 1657 | struct zap_details *details) |
| 1658 | { |
| 1659 | unsigned long restart_addr; |
| 1660 | int need_break; |
| 1661 | |
| 1662 | again: |
| 1663 | restart_addr = vma->vm_truncate_count; |
| 1664 | if (is_restart_addr(restart_addr) && start_addr < restart_addr) { |
| 1665 | start_addr = restart_addr; |
| 1666 | if (start_addr >= end_addr) { |
| 1667 | /* Top of vma has been split off since last time */ |
| 1668 | vma->vm_truncate_count = details->truncate_count; |
| 1669 | return 0; |
| 1670 | } |
| 1671 | } |
| 1672 | |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1673 | restart_addr = zap_page_range(vma, start_addr, |
| 1674 | end_addr - start_addr, details); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1675 | need_break = need_resched() || |
| 1676 | need_lockbreak(details->i_mmap_lock); |
| 1677 | |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1678 | if (restart_addr >= end_addr) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1679 | /* We have now completed this vma: mark it so */ |
| 1680 | vma->vm_truncate_count = details->truncate_count; |
| 1681 | if (!need_break) |
| 1682 | return 0; |
| 1683 | } else { |
| 1684 | /* Note restart_addr in vma's truncate_count field */ |
Hugh Dickins | ee39b37 | 2005-04-19 13:29:15 -0700 | [diff] [blame] | 1685 | vma->vm_truncate_count = restart_addr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1686 | if (!need_break) |
| 1687 | goto again; |
| 1688 | } |
| 1689 | |
| 1690 | spin_unlock(details->i_mmap_lock); |
| 1691 | cond_resched(); |
| 1692 | spin_lock(details->i_mmap_lock); |
| 1693 | return -EINTR; |
| 1694 | } |
| 1695 | |
| 1696 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, |
| 1697 | struct zap_details *details) |
| 1698 | { |
| 1699 | struct vm_area_struct *vma; |
| 1700 | struct prio_tree_iter iter; |
| 1701 | pgoff_t vba, vea, zba, zea; |
| 1702 | |
| 1703 | restart: |
| 1704 | vma_prio_tree_foreach(vma, &iter, root, |
| 1705 | details->first_index, details->last_index) { |
| 1706 | /* Skip quickly over those we have already dealt with */ |
| 1707 | if (vma->vm_truncate_count == details->truncate_count) |
| 1708 | continue; |
| 1709 | |
| 1710 | vba = vma->vm_pgoff; |
| 1711 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; |
| 1712 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ |
| 1713 | zba = details->first_index; |
| 1714 | if (zba < vba) |
| 1715 | zba = vba; |
| 1716 | zea = details->last_index; |
| 1717 | if (zea > vea) |
| 1718 | zea = vea; |
| 1719 | |
| 1720 | if (unmap_mapping_range_vma(vma, |
| 1721 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, |
| 1722 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, |
| 1723 | details) < 0) |
| 1724 | goto restart; |
| 1725 | } |
| 1726 | } |
| 1727 | |
| 1728 | static inline void unmap_mapping_range_list(struct list_head *head, |
| 1729 | struct zap_details *details) |
| 1730 | { |
| 1731 | struct vm_area_struct *vma; |
| 1732 | |
| 1733 | /* |
| 1734 | * In nonlinear VMAs there is no correspondence between virtual address |
| 1735 | * offset and file offset. So we must perform an exhaustive search |
| 1736 | * across *all* the pages in each nonlinear VMA, not just the pages |
| 1737 | * whose virtual address lies outside the file truncation point. |
| 1738 | */ |
| 1739 | restart: |
| 1740 | list_for_each_entry(vma, head, shared.vm_set.list) { |
| 1741 | /* Skip quickly over those we have already dealt with */ |
| 1742 | if (vma->vm_truncate_count == details->truncate_count) |
| 1743 | continue; |
| 1744 | details->nonlinear_vma = vma; |
| 1745 | if (unmap_mapping_range_vma(vma, vma->vm_start, |
| 1746 | vma->vm_end, details) < 0) |
| 1747 | goto restart; |
| 1748 | } |
| 1749 | } |
| 1750 | |
| 1751 | /** |
| 1752 | * unmap_mapping_range - unmap the portion of all mmaps |
| 1753 | * in the specified address_space corresponding to the specified |
| 1754 | * page range in the underlying file. |
Martin Waitz | 3d41088 | 2005-06-23 22:05:21 -0700 | [diff] [blame] | 1755 | * @mapping: the address space containing mmaps to be unmapped. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1756 | * @holebegin: byte in first page to unmap, relative to the start of |
| 1757 | * the underlying file. This will be rounded down to a PAGE_SIZE |
| 1758 | * boundary. Note that this is different from vmtruncate(), which |
| 1759 | * must keep the partial page. In contrast, we must get rid of |
| 1760 | * partial pages. |
| 1761 | * @holelen: size of prospective hole in bytes. This will be rounded |
| 1762 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the |
| 1763 | * end of the file. |
| 1764 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; |
| 1765 | * but 0 when invalidating pagecache, don't throw away private data. |
| 1766 | */ |
| 1767 | void unmap_mapping_range(struct address_space *mapping, |
| 1768 | loff_t const holebegin, loff_t const holelen, int even_cows) |
| 1769 | { |
| 1770 | struct zap_details details; |
| 1771 | pgoff_t hba = holebegin >> PAGE_SHIFT; |
| 1772 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1773 | |
| 1774 | /* Check for overflow. */ |
| 1775 | if (sizeof(holelen) > sizeof(hlen)) { |
| 1776 | long long holeend = |
| 1777 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; |
| 1778 | if (holeend & ~(long long)ULONG_MAX) |
| 1779 | hlen = ULONG_MAX - hba + 1; |
| 1780 | } |
| 1781 | |
| 1782 | details.check_mapping = even_cows? NULL: mapping; |
| 1783 | details.nonlinear_vma = NULL; |
| 1784 | details.first_index = hba; |
| 1785 | details.last_index = hba + hlen - 1; |
| 1786 | if (details.last_index < details.first_index) |
| 1787 | details.last_index = ULONG_MAX; |
| 1788 | details.i_mmap_lock = &mapping->i_mmap_lock; |
| 1789 | |
| 1790 | spin_lock(&mapping->i_mmap_lock); |
| 1791 | |
| 1792 | /* serialize i_size write against truncate_count write */ |
| 1793 | smp_wmb(); |
| 1794 | /* Protect against page faults, and endless unmapping loops */ |
| 1795 | mapping->truncate_count++; |
| 1796 | /* |
| 1797 | * For archs where spin_lock has inclusive semantics like ia64 |
| 1798 | * this smp_mb() will prevent to read pagetable contents |
| 1799 | * before the truncate_count increment is visible to |
| 1800 | * other cpus. |
| 1801 | */ |
| 1802 | smp_mb(); |
| 1803 | if (unlikely(is_restart_addr(mapping->truncate_count))) { |
| 1804 | if (mapping->truncate_count == 0) |
| 1805 | reset_vma_truncate_counts(mapping); |
| 1806 | mapping->truncate_count++; |
| 1807 | } |
| 1808 | details.truncate_count = mapping->truncate_count; |
| 1809 | |
| 1810 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) |
| 1811 | unmap_mapping_range_tree(&mapping->i_mmap, &details); |
| 1812 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) |
| 1813 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); |
| 1814 | spin_unlock(&mapping->i_mmap_lock); |
| 1815 | } |
| 1816 | EXPORT_SYMBOL(unmap_mapping_range); |
| 1817 | |
Rolf Eike Beer | bfa5bf6 | 2006-09-25 23:31:22 -0700 | [diff] [blame] | 1818 | /** |
| 1819 | * vmtruncate - unmap mappings "freed" by truncate() syscall |
| 1820 | * @inode: inode of the file used |
| 1821 | * @offset: file offset to start truncating |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1822 | * |
| 1823 | * NOTE! We have to be ready to update the memory sharing |
| 1824 | * between the file and the memory map for a potential last |
| 1825 | * incomplete page. Ugly, but necessary. |
| 1826 | */ |
| 1827 | int vmtruncate(struct inode * inode, loff_t offset) |
| 1828 | { |
| 1829 | struct address_space *mapping = inode->i_mapping; |
| 1830 | unsigned long limit; |
| 1831 | |
| 1832 | if (inode->i_size < offset) |
| 1833 | goto do_expand; |
| 1834 | /* |
| 1835 | * truncation of in-use swapfiles is disallowed - it would cause |
| 1836 | * subsequent swapout to scribble on the now-freed blocks. |
| 1837 | */ |
| 1838 | if (IS_SWAPFILE(inode)) |
| 1839 | goto out_busy; |
| 1840 | i_size_write(inode, offset); |
| 1841 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); |
| 1842 | truncate_inode_pages(mapping, offset); |
| 1843 | goto out_truncate; |
| 1844 | |
| 1845 | do_expand: |
| 1846 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; |
| 1847 | if (limit != RLIM_INFINITY && offset > limit) |
| 1848 | goto out_sig; |
| 1849 | if (offset > inode->i_sb->s_maxbytes) |
| 1850 | goto out_big; |
| 1851 | i_size_write(inode, offset); |
| 1852 | |
| 1853 | out_truncate: |
| 1854 | if (inode->i_op && inode->i_op->truncate) |
| 1855 | inode->i_op->truncate(inode); |
| 1856 | return 0; |
| 1857 | out_sig: |
| 1858 | send_sig(SIGXFSZ, current, 0); |
| 1859 | out_big: |
| 1860 | return -EFBIG; |
| 1861 | out_busy: |
| 1862 | return -ETXTBSY; |
| 1863 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1864 | EXPORT_SYMBOL(vmtruncate); |
| 1865 | |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 1866 | int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) |
| 1867 | { |
| 1868 | struct address_space *mapping = inode->i_mapping; |
| 1869 | |
| 1870 | /* |
| 1871 | * If the underlying filesystem is not going to provide |
| 1872 | * a way to truncate a range of blocks (punch a hole) - |
| 1873 | * we should return failure right now. |
| 1874 | */ |
| 1875 | if (!inode->i_op || !inode->i_op->truncate_range) |
| 1876 | return -ENOSYS; |
| 1877 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1878 | mutex_lock(&inode->i_mutex); |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 1879 | down_write(&inode->i_alloc_sem); |
| 1880 | unmap_mapping_range(mapping, offset, (end - offset), 1); |
| 1881 | truncate_inode_pages_range(mapping, offset, end); |
| 1882 | inode->i_op->truncate_range(inode, offset, end); |
| 1883 | up_write(&inode->i_alloc_sem); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 1884 | mutex_unlock(&inode->i_mutex); |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 1885 | |
| 1886 | return 0; |
| 1887 | } |
Adrian Bunk | 26fc523 | 2006-07-10 04:44:22 -0700 | [diff] [blame] | 1888 | EXPORT_UNUSED_SYMBOL(vmtruncate_range); /* June 2006 */ |
Badari Pulavarty | f6b3ec2 | 2006-01-06 00:10:38 -0800 | [diff] [blame] | 1889 | |
Rolf Eike Beer | bfa5bf6 | 2006-09-25 23:31:22 -0700 | [diff] [blame] | 1890 | /** |
| 1891 | * swapin_readahead - swap in pages in hope we need them soon |
| 1892 | * @entry: swap entry of this memory |
| 1893 | * @addr: address to start |
| 1894 | * @vma: user vma this addresses belong to |
| 1895 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1896 | * Primitive swap readahead code. We simply read an aligned block of |
| 1897 | * (1 << page_cluster) entries in the swap area. This method is chosen |
| 1898 | * because it doesn't cost us any seek time. We also make sure to queue |
Rolf Eike Beer | bfa5bf6 | 2006-09-25 23:31:22 -0700 | [diff] [blame] | 1899 | * the 'original' request together with the readahead ones... |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1900 | * |
| 1901 | * This has been extended to use the NUMA policies from the mm triggering |
| 1902 | * the readahead. |
| 1903 | * |
| 1904 | * Caller must hold down_read on the vma->vm_mm if vma is not NULL. |
| 1905 | */ |
| 1906 | void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma) |
| 1907 | { |
| 1908 | #ifdef CONFIG_NUMA |
| 1909 | struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL; |
| 1910 | #endif |
| 1911 | int i, num; |
| 1912 | struct page *new_page; |
| 1913 | unsigned long offset; |
| 1914 | |
| 1915 | /* |
| 1916 | * Get the number of handles we should do readahead io to. |
| 1917 | */ |
| 1918 | num = valid_swaphandles(entry, &offset); |
| 1919 | for (i = 0; i < num; offset++, i++) { |
| 1920 | /* Ok, do the async read-ahead now */ |
| 1921 | new_page = read_swap_cache_async(swp_entry(swp_type(entry), |
| 1922 | offset), vma, addr); |
| 1923 | if (!new_page) |
| 1924 | break; |
| 1925 | page_cache_release(new_page); |
| 1926 | #ifdef CONFIG_NUMA |
| 1927 | /* |
| 1928 | * Find the next applicable VMA for the NUMA policy. |
| 1929 | */ |
| 1930 | addr += PAGE_SIZE; |
| 1931 | if (addr == 0) |
| 1932 | vma = NULL; |
| 1933 | if (vma) { |
| 1934 | if (addr >= vma->vm_end) { |
| 1935 | vma = next_vma; |
| 1936 | next_vma = vma ? vma->vm_next : NULL; |
| 1937 | } |
| 1938 | if (vma && addr < vma->vm_start) |
| 1939 | vma = NULL; |
| 1940 | } else { |
| 1941 | if (next_vma && addr >= next_vma->vm_start) { |
| 1942 | vma = next_vma; |
| 1943 | next_vma = vma->vm_next; |
| 1944 | } |
| 1945 | } |
| 1946 | #endif |
| 1947 | } |
| 1948 | lru_add_drain(); /* Push any new pages onto the LRU now */ |
| 1949 | } |
| 1950 | |
| 1951 | /* |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1952 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 1953 | * but allow concurrent faults), and pte mapped but not yet locked. |
| 1954 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1955 | */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1956 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1957 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
| 1958 | int write_access, pte_t orig_pte) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1959 | { |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1960 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1961 | struct page *page; |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1962 | swp_entry_t entry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1963 | pte_t pte; |
| 1964 | int ret = VM_FAULT_MINOR; |
| 1965 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 1966 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1967 | goto out; |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1968 | |
| 1969 | entry = pte_to_swp_entry(orig_pte); |
Christoph Lameter | 0697212 | 2006-06-23 02:03:35 -0700 | [diff] [blame] | 1970 | if (is_migration_entry(entry)) { |
| 1971 | migration_entry_wait(mm, pmd, address); |
| 1972 | goto out; |
| 1973 | } |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 1974 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1975 | page = lookup_swap_cache(entry); |
| 1976 | if (!page) { |
| 1977 | swapin_readahead(entry, address, vma); |
| 1978 | page = read_swap_cache_async(entry, vma, address); |
| 1979 | if (!page) { |
| 1980 | /* |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1981 | * Back out if somebody else faulted in this pte |
| 1982 | * while we released the pte lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1983 | */ |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 1984 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1985 | if (likely(pte_same(*page_table, orig_pte))) |
| 1986 | ret = VM_FAULT_OOM; |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 1987 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 1988 | goto unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1989 | } |
| 1990 | |
| 1991 | /* Had to read the page from swap area: Major fault */ |
| 1992 | ret = VM_FAULT_MAJOR; |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 1993 | count_vm_event(PGMAJFAULT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1994 | grab_swap_token(); |
| 1995 | } |
| 1996 | |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 1997 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1998 | mark_page_accessed(page); |
| 1999 | lock_page(page); |
| 2000 | |
| 2001 | /* |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2002 | * Back out if somebody else already faulted in this pte. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2003 | */ |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2004 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
Hugh Dickins | 9e9bef0 | 2005-10-29 18:16:15 -0700 | [diff] [blame] | 2005 | if (unlikely(!pte_same(*page_table, orig_pte))) |
Kirill Korotaev | b810748 | 2005-05-16 21:53:50 -0700 | [diff] [blame] | 2006 | goto out_nomap; |
Kirill Korotaev | b810748 | 2005-05-16 21:53:50 -0700 | [diff] [blame] | 2007 | |
| 2008 | if (unlikely(!PageUptodate(page))) { |
| 2009 | ret = VM_FAULT_SIGBUS; |
| 2010 | goto out_nomap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2011 | } |
| 2012 | |
| 2013 | /* The page isn't present yet, go ahead with the fault. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2014 | |
Hugh Dickins | 4294621 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 2015 | inc_mm_counter(mm, anon_rss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2016 | pte = mk_pte(page, vma->vm_page_prot); |
| 2017 | if (write_access && can_share_swap_page(page)) { |
| 2018 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); |
| 2019 | write_access = 0; |
| 2020 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2021 | |
| 2022 | flush_icache_page(vma, page); |
| 2023 | set_pte_at(mm, address, page_table, pte); |
| 2024 | page_add_anon_rmap(page, vma, address); |
| 2025 | |
Hugh Dickins | c475a8a | 2005-06-21 17:15:12 -0700 | [diff] [blame] | 2026 | swap_free(entry); |
| 2027 | if (vm_swap_full()) |
| 2028 | remove_exclusive_swap_page(page); |
| 2029 | unlock_page(page); |
| 2030 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2031 | if (write_access) { |
| 2032 | if (do_wp_page(mm, vma, address, |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2033 | page_table, pmd, ptl, pte) == VM_FAULT_OOM) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2034 | ret = VM_FAULT_OOM; |
| 2035 | goto out; |
| 2036 | } |
| 2037 | |
| 2038 | /* No need to invalidate - it was non-present before */ |
| 2039 | update_mmu_cache(vma, address, pte); |
| 2040 | lazy_mmu_prot_update(pte); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2041 | unlock: |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2042 | pte_unmap_unlock(page_table, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | out: |
| 2044 | return ret; |
Kirill Korotaev | b810748 | 2005-05-16 21:53:50 -0700 | [diff] [blame] | 2045 | out_nomap: |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2046 | pte_unmap_unlock(page_table, ptl); |
Kirill Korotaev | b810748 | 2005-05-16 21:53:50 -0700 | [diff] [blame] | 2047 | unlock_page(page); |
| 2048 | page_cache_release(page); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2049 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2050 | } |
| 2051 | |
| 2052 | /* |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2053 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 2054 | * but allow concurrent faults), and pte mapped but not yet locked. |
| 2055 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2056 | */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2057 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 2058 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
| 2059 | int write_access) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2060 | { |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2061 | struct page *page; |
| 2062 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2063 | pte_t entry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2064 | |
Linus Torvalds | 6aab341 | 2005-11-28 14:34:23 -0800 | [diff] [blame] | 2065 | if (write_access) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2066 | /* Allocate our own private page. */ |
| 2067 | pte_unmap(page_table); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2068 | |
| 2069 | if (unlikely(anon_vma_prepare(vma))) |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2070 | goto oom; |
| 2071 | page = alloc_zeroed_user_highpage(vma, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2072 | if (!page) |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2073 | goto oom; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2074 | |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2075 | entry = mk_pte(page, vma->vm_page_prot); |
| 2076 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2077 | |
| 2078 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
| 2079 | if (!pte_none(*page_table)) |
| 2080 | goto release; |
| 2081 | inc_mm_counter(mm, anon_rss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2082 | lru_cache_add_active(page); |
Nick Piggin | 9617d95 | 2006-01-06 00:11:12 -0800 | [diff] [blame] | 2083 | page_add_new_anon_rmap(page, vma, address); |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 2084 | } else { |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2085 | /* Map the ZERO_PAGE - vm_page_prot is readonly */ |
| 2086 | page = ZERO_PAGE(address); |
| 2087 | page_cache_get(page); |
| 2088 | entry = mk_pte(page, vma->vm_page_prot); |
| 2089 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 2090 | ptl = pte_lockptr(mm, pmd); |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2091 | spin_lock(ptl); |
| 2092 | if (!pte_none(*page_table)) |
| 2093 | goto release; |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 2094 | inc_mm_counter(mm, file_rss); |
| 2095 | page_add_file_rmap(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2096 | } |
| 2097 | |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2098 | set_pte_at(mm, address, page_table, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2099 | |
| 2100 | /* No need to invalidate - it was non-present before */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2101 | update_mmu_cache(vma, address, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2102 | lazy_mmu_prot_update(entry); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2103 | unlock: |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2104 | pte_unmap_unlock(page_table, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2105 | return VM_FAULT_MINOR; |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2106 | release: |
| 2107 | page_cache_release(page); |
| 2108 | goto unlock; |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2109 | oom: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2110 | return VM_FAULT_OOM; |
| 2111 | } |
| 2112 | |
| 2113 | /* |
| 2114 | * do_no_page() tries to create a new page mapping. It aggressively |
| 2115 | * tries to share with existing pages, but makes a separate copy if |
| 2116 | * the "write_access" parameter is true in order to avoid the next |
| 2117 | * page fault. |
| 2118 | * |
| 2119 | * As this is called only for pages that do not currently exist, we |
| 2120 | * do not need to flush old virtual caches or the TLB. |
| 2121 | * |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2122 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 2123 | * but allow concurrent faults), and pte mapped but not yet locked. |
| 2124 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2125 | */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2126 | static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 2127 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
| 2128 | int write_access) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2129 | { |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2130 | spinlock_t *ptl; |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2131 | struct page *new_page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2132 | struct address_space *mapping = NULL; |
| 2133 | pte_t entry; |
| 2134 | unsigned int sequence = 0; |
| 2135 | int ret = VM_FAULT_MINOR; |
| 2136 | int anon = 0; |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 2137 | struct page *dirty_page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2138 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2139 | pte_unmap(page_table); |
Hugh Dickins | 325f04d | 2005-11-29 16:55:48 +0000 | [diff] [blame] | 2140 | BUG_ON(vma->vm_flags & VM_PFNMAP); |
| 2141 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2142 | if (vma->vm_file) { |
| 2143 | mapping = vma->vm_file->f_mapping; |
| 2144 | sequence = mapping->truncate_count; |
| 2145 | smp_rmb(); /* serializes i_size against truncate_count */ |
| 2146 | } |
| 2147 | retry: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2148 | new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); |
| 2149 | /* |
| 2150 | * No smp_rmb is needed here as long as there's a full |
| 2151 | * spin_lock/unlock sequence inside the ->nopage callback |
| 2152 | * (for the pagecache lookup) that acts as an implicit |
| 2153 | * smp_mb() and prevents the i_size read to happen |
| 2154 | * after the next truncate_count read. |
| 2155 | */ |
| 2156 | |
| 2157 | /* no page was available -- either SIGBUS or OOM */ |
| 2158 | if (new_page == NOPAGE_SIGBUS) |
| 2159 | return VM_FAULT_SIGBUS; |
| 2160 | if (new_page == NOPAGE_OOM) |
| 2161 | return VM_FAULT_OOM; |
| 2162 | |
| 2163 | /* |
| 2164 | * Should we do an early C-O-W break? |
| 2165 | */ |
David Howells | 9637a5e | 2006-06-23 02:03:43 -0700 | [diff] [blame] | 2166 | if (write_access) { |
| 2167 | if (!(vma->vm_flags & VM_SHARED)) { |
| 2168 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2169 | |
David Howells | 9637a5e | 2006-06-23 02:03:43 -0700 | [diff] [blame] | 2170 | if (unlikely(anon_vma_prepare(vma))) |
| 2171 | goto oom; |
| 2172 | page = alloc_page_vma(GFP_HIGHUSER, vma, address); |
| 2173 | if (!page) |
| 2174 | goto oom; |
| 2175 | copy_user_highpage(page, new_page, address); |
| 2176 | page_cache_release(new_page); |
| 2177 | new_page = page; |
| 2178 | anon = 1; |
| 2179 | |
| 2180 | } else { |
| 2181 | /* if the page will be shareable, see if the backing |
| 2182 | * address space wants to know that the page is about |
| 2183 | * to become writable */ |
| 2184 | if (vma->vm_ops->page_mkwrite && |
| 2185 | vma->vm_ops->page_mkwrite(vma, new_page) < 0 |
| 2186 | ) { |
| 2187 | page_cache_release(new_page); |
| 2188 | return VM_FAULT_SIGBUS; |
| 2189 | } |
| 2190 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2191 | } |
| 2192 | |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2193 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2194 | /* |
| 2195 | * For a file-backed vma, someone could have truncated or otherwise |
| 2196 | * invalidated this page. If unmap_mapping_range got called, |
| 2197 | * retry getting the page. |
| 2198 | */ |
| 2199 | if (mapping && unlikely(sequence != mapping->truncate_count)) { |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2200 | pte_unmap_unlock(page_table, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2201 | page_cache_release(new_page); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2202 | cond_resched(); |
| 2203 | sequence = mapping->truncate_count; |
| 2204 | smp_rmb(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2205 | goto retry; |
| 2206 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2207 | |
| 2208 | /* |
| 2209 | * This silly early PAGE_DIRTY setting removes a race |
| 2210 | * due to the bad i386 page protection. But it's valid |
| 2211 | * for other architectures too. |
| 2212 | * |
| 2213 | * Note that if write_access is true, we either now have |
| 2214 | * an exclusive copy of the page, or this is a shared mapping, |
| 2215 | * so we can make it writable and dirty to avoid having to |
| 2216 | * handle that later. |
| 2217 | */ |
| 2218 | /* Only go through if we didn't race with anybody else... */ |
| 2219 | if (pte_none(*page_table)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2220 | flush_icache_page(vma, new_page); |
| 2221 | entry = mk_pte(new_page, vma->vm_page_prot); |
| 2222 | if (write_access) |
| 2223 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
| 2224 | set_pte_at(mm, address, page_table, entry); |
| 2225 | if (anon) { |
Hugh Dickins | 4294621 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 2226 | inc_mm_counter(mm, anon_rss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2227 | lru_cache_add_active(new_page); |
Nick Piggin | 9617d95 | 2006-01-06 00:11:12 -0800 | [diff] [blame] | 2228 | page_add_new_anon_rmap(new_page, vma, address); |
Hugh Dickins | f57e88a | 2005-11-21 21:32:19 -0800 | [diff] [blame] | 2229 | } else { |
Hugh Dickins | 4294621 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 2230 | inc_mm_counter(mm, file_rss); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2231 | page_add_file_rmap(new_page); |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 2232 | if (write_access) { |
| 2233 | dirty_page = new_page; |
| 2234 | get_page(dirty_page); |
| 2235 | } |
Hugh Dickins | 4294621 | 2005-10-29 18:16:05 -0700 | [diff] [blame] | 2236 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2237 | } else { |
| 2238 | /* One of our sibling threads was faster, back out. */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2239 | page_cache_release(new_page); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2240 | goto unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2241 | } |
| 2242 | |
| 2243 | /* no need to invalidate: a not-present page shouldn't be cached */ |
| 2244 | update_mmu_cache(vma, address, entry); |
| 2245 | lazy_mmu_prot_update(entry); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2246 | unlock: |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2247 | pte_unmap_unlock(page_table, ptl); |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 2248 | if (dirty_page) { |
Peter Zijlstra | edc79b2 | 2006-09-25 23:30:58 -0700 | [diff] [blame] | 2249 | set_page_dirty_balance(dirty_page); |
Peter Zijlstra | d08b385 | 2006-09-25 23:30:57 -0700 | [diff] [blame] | 2250 | put_page(dirty_page); |
| 2251 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2252 | return ret; |
| 2253 | oom: |
| 2254 | page_cache_release(new_page); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2255 | return VM_FAULT_OOM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2256 | } |
| 2257 | |
| 2258 | /* |
Jes Sorensen | f4b8180 | 2006-09-27 01:50:10 -0700 | [diff] [blame] | 2259 | * do_no_pfn() tries to create a new page mapping for a page without |
| 2260 | * a struct_page backing it |
| 2261 | * |
| 2262 | * As this is called only for pages that do not currently exist, we |
| 2263 | * do not need to flush old virtual caches or the TLB. |
| 2264 | * |
| 2265 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 2266 | * but allow concurrent faults), and pte mapped but not yet locked. |
| 2267 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
| 2268 | * |
| 2269 | * It is expected that the ->nopfn handler always returns the same pfn |
| 2270 | * for a given virtual mapping. |
| 2271 | * |
| 2272 | * Mark this `noinline' to prevent it from bloating the main pagefault code. |
| 2273 | */ |
| 2274 | static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, |
| 2275 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
| 2276 | int write_access) |
| 2277 | { |
| 2278 | spinlock_t *ptl; |
| 2279 | pte_t entry; |
| 2280 | unsigned long pfn; |
| 2281 | int ret = VM_FAULT_MINOR; |
| 2282 | |
| 2283 | pte_unmap(page_table); |
| 2284 | BUG_ON(!(vma->vm_flags & VM_PFNMAP)); |
| 2285 | BUG_ON(is_cow_mapping(vma->vm_flags)); |
| 2286 | |
| 2287 | pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK); |
| 2288 | if (pfn == NOPFN_OOM) |
| 2289 | return VM_FAULT_OOM; |
| 2290 | if (pfn == NOPFN_SIGBUS) |
| 2291 | return VM_FAULT_SIGBUS; |
| 2292 | |
| 2293 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
| 2294 | |
| 2295 | /* Only go through if we didn't race with anybody else... */ |
| 2296 | if (pte_none(*page_table)) { |
| 2297 | entry = pfn_pte(pfn, vma->vm_page_prot); |
| 2298 | if (write_access) |
| 2299 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
| 2300 | set_pte_at(mm, address, page_table, entry); |
| 2301 | } |
| 2302 | pte_unmap_unlock(page_table, ptl); |
| 2303 | return ret; |
| 2304 | } |
| 2305 | |
| 2306 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2307 | * Fault of a previously existing named mapping. Repopulate the pte |
| 2308 | * from the encoded file_pte if possible. This enables swappable |
| 2309 | * nonlinear vmas. |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2310 | * |
| 2311 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 2312 | * but allow concurrent faults), and pte mapped but not yet locked. |
| 2313 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2314 | */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2315 | static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 2316 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
| 2317 | int write_access, pte_t orig_pte) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2318 | { |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2319 | pgoff_t pgoff; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2320 | int err; |
| 2321 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 2322 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2323 | return VM_FAULT_MINOR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2324 | |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2325 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { |
| 2326 | /* |
| 2327 | * Page table corrupted: show pte and kill process. |
| 2328 | */ |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 2329 | print_bad_pte(vma, orig_pte, address); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2330 | return VM_FAULT_OOM; |
| 2331 | } |
| 2332 | /* We can then assume vm->vm_ops && vma->vm_ops->populate */ |
| 2333 | |
| 2334 | pgoff = pte_to_pgoff(orig_pte); |
| 2335 | err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, |
| 2336 | vma->vm_page_prot, pgoff, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2337 | if (err == -ENOMEM) |
| 2338 | return VM_FAULT_OOM; |
| 2339 | if (err) |
| 2340 | return VM_FAULT_SIGBUS; |
| 2341 | return VM_FAULT_MAJOR; |
| 2342 | } |
| 2343 | |
| 2344 | /* |
| 2345 | * These routines also need to handle stuff like marking pages dirty |
| 2346 | * and/or accessed for architectures that don't do it in hardware (most |
| 2347 | * RISC architectures). The early dirtying is also good on the i386. |
| 2348 | * |
| 2349 | * There is also a hook called "update_mmu_cache()" that architectures |
| 2350 | * with external mmu caches can use to update those (ie the Sparc or |
| 2351 | * PowerPC hashed page tables that act as extended TLBs). |
| 2352 | * |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2353 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
| 2354 | * but allow concurrent faults), and pte mapped but not yet locked. |
| 2355 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2356 | */ |
| 2357 | static inline int handle_pte_fault(struct mm_struct *mm, |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2358 | struct vm_area_struct *vma, unsigned long address, |
| 2359 | pte_t *pte, pmd_t *pmd, int write_access) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2360 | { |
| 2361 | pte_t entry; |
Andrea Arcangeli | 1a44e14 | 2005-10-29 18:16:48 -0700 | [diff] [blame] | 2362 | pte_t old_entry; |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2363 | spinlock_t *ptl; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2364 | |
Andrea Arcangeli | 1a44e14 | 2005-10-29 18:16:48 -0700 | [diff] [blame] | 2365 | old_entry = entry = *pte; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2366 | if (!pte_present(entry)) { |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2367 | if (pte_none(entry)) { |
Jes Sorensen | f4b8180 | 2006-09-27 01:50:10 -0700 | [diff] [blame] | 2368 | if (vma->vm_ops) { |
| 2369 | if (vma->vm_ops->nopage) |
| 2370 | return do_no_page(mm, vma, address, |
| 2371 | pte, pmd, |
| 2372 | write_access); |
| 2373 | if (unlikely(vma->vm_ops->nopfn)) |
| 2374 | return do_no_pfn(mm, vma, address, pte, |
| 2375 | pmd, write_access); |
| 2376 | } |
| 2377 | return do_anonymous_page(mm, vma, address, |
| 2378 | pte, pmd, write_access); |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2379 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2380 | if (pte_file(entry)) |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2381 | return do_file_page(mm, vma, address, |
| 2382 | pte, pmd, write_access, entry); |
| 2383 | return do_swap_page(mm, vma, address, |
| 2384 | pte, pmd, write_access, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2385 | } |
| 2386 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 2387 | ptl = pte_lockptr(mm, pmd); |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2388 | spin_lock(ptl); |
| 2389 | if (unlikely(!pte_same(*pte, entry))) |
| 2390 | goto unlock; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2391 | if (write_access) { |
| 2392 | if (!pte_write(entry)) |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2393 | return do_wp_page(mm, vma, address, |
| 2394 | pte, pmd, ptl, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2395 | entry = pte_mkdirty(entry); |
| 2396 | } |
| 2397 | entry = pte_mkyoung(entry); |
Andrea Arcangeli | 1a44e14 | 2005-10-29 18:16:48 -0700 | [diff] [blame] | 2398 | if (!pte_same(old_entry, entry)) { |
| 2399 | ptep_set_access_flags(vma, address, pte, entry, write_access); |
| 2400 | update_mmu_cache(vma, address, entry); |
| 2401 | lazy_mmu_prot_update(entry); |
| 2402 | } else { |
| 2403 | /* |
| 2404 | * This is needed only for protection faults but the arch code |
| 2405 | * is not yet telling us if this is a protection fault or not. |
| 2406 | * This still avoids useless tlb flushes for .text page faults |
| 2407 | * with threads. |
| 2408 | */ |
| 2409 | if (write_access) |
| 2410 | flush_tlb_page(vma, address); |
| 2411 | } |
Hugh Dickins | 8f4e210 | 2005-10-29 18:16:26 -0700 | [diff] [blame] | 2412 | unlock: |
| 2413 | pte_unmap_unlock(pte, ptl); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2414 | return VM_FAULT_MINOR; |
| 2415 | } |
| 2416 | |
| 2417 | /* |
| 2418 | * By the time we get here, we already hold the mm semaphore |
| 2419 | */ |
Hugh Dickins | 65500d2 | 2005-10-29 18:15:59 -0700 | [diff] [blame] | 2420 | 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] | 2421 | unsigned long address, int write_access) |
| 2422 | { |
| 2423 | pgd_t *pgd; |
| 2424 | pud_t *pud; |
| 2425 | pmd_t *pmd; |
| 2426 | pte_t *pte; |
| 2427 | |
| 2428 | __set_current_state(TASK_RUNNING); |
| 2429 | |
Christoph Lameter | f8891e5 | 2006-06-30 01:55:45 -0700 | [diff] [blame] | 2430 | count_vm_event(PGFAULT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2431 | |
Hugh Dickins | ac9b9c6 | 2005-10-20 16:24:28 +0100 | [diff] [blame] | 2432 | if (unlikely(is_vm_hugetlb_page(vma))) |
| 2433 | return hugetlb_fault(mm, vma, address, write_access); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2434 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2435 | pgd = pgd_offset(mm, address); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2436 | pud = pud_alloc(mm, pgd, address); |
| 2437 | if (!pud) |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2438 | return VM_FAULT_OOM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2439 | pmd = pmd_alloc(mm, pud, address); |
| 2440 | if (!pmd) |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2441 | return VM_FAULT_OOM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2442 | pte = pte_alloc_map(mm, pmd, address); |
| 2443 | if (!pte) |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2444 | return VM_FAULT_OOM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2445 | |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2446 | return handle_pte_fault(mm, vma, address, pte, pmd, write_access); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2447 | } |
| 2448 | |
Arnd Bergmann | 67207b9 | 2005-11-15 15:53:48 -0500 | [diff] [blame] | 2449 | EXPORT_SYMBOL_GPL(__handle_mm_fault); |
| 2450 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2451 | #ifndef __PAGETABLE_PUD_FOLDED |
| 2452 | /* |
| 2453 | * Allocate page upper directory. |
Hugh Dickins | 872fec1 | 2005-10-29 18:16:21 -0700 | [diff] [blame] | 2454 | * We've already handled the fast-path in-line. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2455 | */ |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2456 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2457 | { |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2458 | pud_t *new = pud_alloc_one(mm, address); |
| 2459 | if (!new) |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2460 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2461 | |
Hugh Dickins | 872fec1 | 2005-10-29 18:16:21 -0700 | [diff] [blame] | 2462 | spin_lock(&mm->page_table_lock); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2463 | if (pgd_present(*pgd)) /* Another has populated it */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2464 | pud_free(new); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2465 | else |
| 2466 | pgd_populate(mm, pgd, new); |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2467 | spin_unlock(&mm->page_table_lock); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2468 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2469 | } |
Alan Stern | e0f3959 | 2005-11-28 13:43:44 -0800 | [diff] [blame] | 2470 | #else |
| 2471 | /* Workaround for gcc 2.96 */ |
| 2472 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
| 2473 | { |
| 2474 | return 0; |
| 2475 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2476 | #endif /* __PAGETABLE_PUD_FOLDED */ |
| 2477 | |
| 2478 | #ifndef __PAGETABLE_PMD_FOLDED |
| 2479 | /* |
| 2480 | * Allocate page middle directory. |
Hugh Dickins | 872fec1 | 2005-10-29 18:16:21 -0700 | [diff] [blame] | 2481 | * We've already handled the fast-path in-line. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2482 | */ |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2483 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2484 | { |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2485 | pmd_t *new = pmd_alloc_one(mm, address); |
| 2486 | if (!new) |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2487 | return -ENOMEM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2488 | |
Hugh Dickins | 872fec1 | 2005-10-29 18:16:21 -0700 | [diff] [blame] | 2489 | spin_lock(&mm->page_table_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2490 | #ifndef __ARCH_HAS_4LEVEL_HACK |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2491 | if (pud_present(*pud)) /* Another has populated it */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2492 | pmd_free(new); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2493 | else |
| 2494 | pud_populate(mm, pud, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2495 | #else |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2496 | if (pgd_present(*pud)) /* Another has populated it */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2497 | pmd_free(new); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2498 | else |
| 2499 | pgd_populate(mm, pud, new); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2500 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
Hugh Dickins | c74df32 | 2005-10-29 18:16:23 -0700 | [diff] [blame] | 2501 | spin_unlock(&mm->page_table_lock); |
Hugh Dickins | 1bb3630 | 2005-10-29 18:16:22 -0700 | [diff] [blame] | 2502 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2503 | } |
Alan Stern | e0f3959 | 2005-11-28 13:43:44 -0800 | [diff] [blame] | 2504 | #else |
| 2505 | /* Workaround for gcc 2.96 */ |
| 2506 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
| 2507 | { |
| 2508 | return 0; |
| 2509 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2510 | #endif /* __PAGETABLE_PMD_FOLDED */ |
| 2511 | |
| 2512 | int make_pages_present(unsigned long addr, unsigned long end) |
| 2513 | { |
| 2514 | int ret, len, write; |
| 2515 | struct vm_area_struct * vma; |
| 2516 | |
| 2517 | vma = find_vma(current->mm, addr); |
| 2518 | if (!vma) |
| 2519 | return -1; |
| 2520 | write = (vma->vm_flags & VM_WRITE) != 0; |
Eric Sesterhenn | 5bcb28b | 2006-03-26 18:30:52 +0200 | [diff] [blame] | 2521 | BUG_ON(addr >= end); |
| 2522 | BUG_ON(end > vma->vm_end); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2523 | len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE; |
| 2524 | ret = get_user_pages(current, current->mm, addr, |
| 2525 | len, write, 0, NULL, NULL); |
| 2526 | if (ret < 0) |
| 2527 | return ret; |
| 2528 | return ret == len ? 0 : -1; |
| 2529 | } |
| 2530 | |
| 2531 | /* |
| 2532 | * Map a vmalloc()-space virtual address to the physical page. |
| 2533 | */ |
| 2534 | struct page * vmalloc_to_page(void * vmalloc_addr) |
| 2535 | { |
| 2536 | unsigned long addr = (unsigned long) vmalloc_addr; |
| 2537 | struct page *page = NULL; |
| 2538 | pgd_t *pgd = pgd_offset_k(addr); |
| 2539 | pud_t *pud; |
| 2540 | pmd_t *pmd; |
| 2541 | pte_t *ptep, pte; |
| 2542 | |
| 2543 | if (!pgd_none(*pgd)) { |
| 2544 | pud = pud_offset(pgd, addr); |
| 2545 | if (!pud_none(*pud)) { |
| 2546 | pmd = pmd_offset(pud, addr); |
| 2547 | if (!pmd_none(*pmd)) { |
| 2548 | ptep = pte_offset_map(pmd, addr); |
| 2549 | pte = *ptep; |
| 2550 | if (pte_present(pte)) |
| 2551 | page = pte_page(pte); |
| 2552 | pte_unmap(ptep); |
| 2553 | } |
| 2554 | } |
| 2555 | } |
| 2556 | return page; |
| 2557 | } |
| 2558 | |
| 2559 | EXPORT_SYMBOL(vmalloc_to_page); |
| 2560 | |
| 2561 | /* |
| 2562 | * Map a vmalloc()-space virtual address to the physical page frame number. |
| 2563 | */ |
| 2564 | unsigned long vmalloc_to_pfn(void * vmalloc_addr) |
| 2565 | { |
| 2566 | return page_to_pfn(vmalloc_to_page(vmalloc_addr)); |
| 2567 | } |
| 2568 | |
| 2569 | EXPORT_SYMBOL(vmalloc_to_pfn); |
| 2570 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2571 | #if !defined(__HAVE_ARCH_GATE_AREA) |
| 2572 | |
| 2573 | #if defined(AT_SYSINFO_EHDR) |
Adrian Bunk | 5ce7852 | 2005-09-10 00:26:28 -0700 | [diff] [blame] | 2574 | static struct vm_area_struct gate_vma; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2575 | |
| 2576 | static int __init gate_vma_init(void) |
| 2577 | { |
| 2578 | gate_vma.vm_mm = NULL; |
| 2579 | gate_vma.vm_start = FIXADDR_USER_START; |
| 2580 | gate_vma.vm_end = FIXADDR_USER_END; |
| 2581 | gate_vma.vm_page_prot = PAGE_READONLY; |
Hugh Dickins | 0b14c17 | 2005-11-21 21:32:15 -0800 | [diff] [blame] | 2582 | gate_vma.vm_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2583 | return 0; |
| 2584 | } |
| 2585 | __initcall(gate_vma_init); |
| 2586 | #endif |
| 2587 | |
| 2588 | struct vm_area_struct *get_gate_vma(struct task_struct *tsk) |
| 2589 | { |
| 2590 | #ifdef AT_SYSINFO_EHDR |
| 2591 | return &gate_vma; |
| 2592 | #else |
| 2593 | return NULL; |
| 2594 | #endif |
| 2595 | } |
| 2596 | |
| 2597 | int in_gate_area_no_task(unsigned long addr) |
| 2598 | { |
| 2599 | #ifdef AT_SYSINFO_EHDR |
| 2600 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) |
| 2601 | return 1; |
| 2602 | #endif |
| 2603 | return 0; |
| 2604 | } |
| 2605 | |
| 2606 | #endif /* __HAVE_ARCH_GATE_AREA */ |