Commit | Line | Data |
---|---|---|
1da177e4 LT |
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> | |
0ff92245 | 50 | #include <linux/delayacct.h> |
1da177e4 | 51 | #include <linux/init.h> |
edc79b2a | 52 | #include <linux/writeback.h> |
1da177e4 LT |
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 | ||
d41dee36 | 63 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
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; | |
1da177e4 LT |
81 | |
82 | EXPORT_SYMBOL(num_physpages); | |
83 | EXPORT_SYMBOL(high_memory); | |
1da177e4 | 84 | |
32a93233 IM |
85 | /* |
86 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
87 | * | |
88 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
89 | * as ancient (libc5 based) binaries can segfault. ) | |
90 | */ | |
91 | int randomize_va_space __read_mostly = | |
92 | #ifdef CONFIG_COMPAT_BRK | |
93 | 1; | |
94 | #else | |
95 | 2; | |
96 | #endif | |
a62eaf15 AK |
97 | |
98 | static int __init disable_randmaps(char *s) | |
99 | { | |
100 | randomize_va_space = 0; | |
9b41046c | 101 | return 1; |
a62eaf15 AK |
102 | } |
103 | __setup("norandmaps", disable_randmaps); | |
104 | ||
105 | ||
1da177e4 LT |
106 | /* |
107 | * If a p?d_bad entry is found while walking page tables, report | |
108 | * the error, before resetting entry to p?d_none. Usually (but | |
109 | * very seldom) called out from the p?d_none_or_clear_bad macros. | |
110 | */ | |
111 | ||
112 | void pgd_clear_bad(pgd_t *pgd) | |
113 | { | |
114 | pgd_ERROR(*pgd); | |
115 | pgd_clear(pgd); | |
116 | } | |
117 | ||
118 | void pud_clear_bad(pud_t *pud) | |
119 | { | |
120 | pud_ERROR(*pud); | |
121 | pud_clear(pud); | |
122 | } | |
123 | ||
124 | void pmd_clear_bad(pmd_t *pmd) | |
125 | { | |
126 | pmd_ERROR(*pmd); | |
127 | pmd_clear(pmd); | |
128 | } | |
129 | ||
130 | /* | |
131 | * Note: this doesn't free the actual pages themselves. That | |
132 | * has been handled earlier when unmapping all the memory regions. | |
133 | */ | |
e0da382c | 134 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) |
1da177e4 | 135 | { |
e0da382c HD |
136 | struct page *page = pmd_page(*pmd); |
137 | pmd_clear(pmd); | |
4c21e2f2 | 138 | pte_lock_deinit(page); |
e0da382c | 139 | pte_free_tlb(tlb, page); |
df849a15 | 140 | dec_zone_page_state(page, NR_PAGETABLE); |
e0da382c | 141 | tlb->mm->nr_ptes--; |
1da177e4 LT |
142 | } |
143 | ||
e0da382c HD |
144 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
145 | unsigned long addr, unsigned long end, | |
146 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
147 | { |
148 | pmd_t *pmd; | |
149 | unsigned long next; | |
e0da382c | 150 | unsigned long start; |
1da177e4 | 151 | |
e0da382c | 152 | start = addr; |
1da177e4 | 153 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
154 | do { |
155 | next = pmd_addr_end(addr, end); | |
156 | if (pmd_none_or_clear_bad(pmd)) | |
157 | continue; | |
e0da382c | 158 | free_pte_range(tlb, pmd); |
1da177e4 LT |
159 | } while (pmd++, addr = next, addr != end); |
160 | ||
e0da382c HD |
161 | start &= PUD_MASK; |
162 | if (start < floor) | |
163 | return; | |
164 | if (ceiling) { | |
165 | ceiling &= PUD_MASK; | |
166 | if (!ceiling) | |
167 | return; | |
1da177e4 | 168 | } |
e0da382c HD |
169 | if (end - 1 > ceiling - 1) |
170 | return; | |
171 | ||
172 | pmd = pmd_offset(pud, start); | |
173 | pud_clear(pud); | |
174 | pmd_free_tlb(tlb, pmd); | |
1da177e4 LT |
175 | } |
176 | ||
e0da382c HD |
177 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
178 | unsigned long addr, unsigned long end, | |
179 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
180 | { |
181 | pud_t *pud; | |
182 | unsigned long next; | |
e0da382c | 183 | unsigned long start; |
1da177e4 | 184 | |
e0da382c | 185 | start = addr; |
1da177e4 | 186 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
187 | do { |
188 | next = pud_addr_end(addr, end); | |
189 | if (pud_none_or_clear_bad(pud)) | |
190 | continue; | |
e0da382c | 191 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
192 | } while (pud++, addr = next, addr != end); |
193 | ||
e0da382c HD |
194 | start &= PGDIR_MASK; |
195 | if (start < floor) | |
196 | return; | |
197 | if (ceiling) { | |
198 | ceiling &= PGDIR_MASK; | |
199 | if (!ceiling) | |
200 | return; | |
1da177e4 | 201 | } |
e0da382c HD |
202 | if (end - 1 > ceiling - 1) |
203 | return; | |
204 | ||
205 | pud = pud_offset(pgd, start); | |
206 | pgd_clear(pgd); | |
207 | pud_free_tlb(tlb, pud); | |
1da177e4 LT |
208 | } |
209 | ||
210 | /* | |
e0da382c HD |
211 | * This function frees user-level page tables of a process. |
212 | * | |
1da177e4 LT |
213 | * Must be called with pagetable lock held. |
214 | */ | |
3bf5ee95 | 215 | void free_pgd_range(struct mmu_gather **tlb, |
e0da382c HD |
216 | unsigned long addr, unsigned long end, |
217 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
218 | { |
219 | pgd_t *pgd; | |
220 | unsigned long next; | |
e0da382c HD |
221 | unsigned long start; |
222 | ||
223 | /* | |
224 | * The next few lines have given us lots of grief... | |
225 | * | |
226 | * Why are we testing PMD* at this top level? Because often | |
227 | * there will be no work to do at all, and we'd prefer not to | |
228 | * go all the way down to the bottom just to discover that. | |
229 | * | |
230 | * Why all these "- 1"s? Because 0 represents both the bottom | |
231 | * of the address space and the top of it (using -1 for the | |
232 | * top wouldn't help much: the masks would do the wrong thing). | |
233 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
234 | * the address space, but end 0 and ceiling 0 refer to the top | |
235 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
236 | * that end 0 case should be mythical). | |
237 | * | |
238 | * Wherever addr is brought up or ceiling brought down, we must | |
239 | * be careful to reject "the opposite 0" before it confuses the | |
240 | * subsequent tests. But what about where end is brought down | |
241 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
242 | * | |
243 | * Whereas we round start (addr) and ceiling down, by different | |
244 | * masks at different levels, in order to test whether a table | |
245 | * now has no other vmas using it, so can be freed, we don't | |
246 | * bother to round floor or end up - the tests don't need that. | |
247 | */ | |
1da177e4 | 248 | |
e0da382c HD |
249 | addr &= PMD_MASK; |
250 | if (addr < floor) { | |
251 | addr += PMD_SIZE; | |
252 | if (!addr) | |
253 | return; | |
254 | } | |
255 | if (ceiling) { | |
256 | ceiling &= PMD_MASK; | |
257 | if (!ceiling) | |
258 | return; | |
259 | } | |
260 | if (end - 1 > ceiling - 1) | |
261 | end -= PMD_SIZE; | |
262 | if (addr > end - 1) | |
263 | return; | |
264 | ||
265 | start = addr; | |
3bf5ee95 | 266 | pgd = pgd_offset((*tlb)->mm, addr); |
1da177e4 LT |
267 | do { |
268 | next = pgd_addr_end(addr, end); | |
269 | if (pgd_none_or_clear_bad(pgd)) | |
270 | continue; | |
3bf5ee95 | 271 | free_pud_range(*tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 272 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
273 | } |
274 | ||
275 | void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma, | |
3bf5ee95 | 276 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
277 | { |
278 | while (vma) { | |
279 | struct vm_area_struct *next = vma->vm_next; | |
280 | unsigned long addr = vma->vm_start; | |
281 | ||
8f4f8c16 HD |
282 | /* |
283 | * Hide vma from rmap and vmtruncate before freeing pgtables | |
284 | */ | |
285 | anon_vma_unlink(vma); | |
286 | unlink_file_vma(vma); | |
287 | ||
9da61aef | 288 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 289 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 290 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
291 | } else { |
292 | /* | |
293 | * Optimization: gather nearby vmas into one call down | |
294 | */ | |
295 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 296 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
297 | vma = next; |
298 | next = vma->vm_next; | |
8f4f8c16 HD |
299 | anon_vma_unlink(vma); |
300 | unlink_file_vma(vma); | |
3bf5ee95 HD |
301 | } |
302 | free_pgd_range(tlb, addr, vma->vm_end, | |
303 | floor, next? next->vm_start: ceiling); | |
304 | } | |
e0da382c HD |
305 | vma = next; |
306 | } | |
1da177e4 LT |
307 | } |
308 | ||
1bb3630e | 309 | int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
1da177e4 | 310 | { |
c74df32c | 311 | struct page *new = pte_alloc_one(mm, address); |
1bb3630e HD |
312 | if (!new) |
313 | return -ENOMEM; | |
314 | ||
4c21e2f2 | 315 | pte_lock_init(new); |
c74df32c | 316 | spin_lock(&mm->page_table_lock); |
4c21e2f2 HD |
317 | if (pmd_present(*pmd)) { /* Another has populated it */ |
318 | pte_lock_deinit(new); | |
5e541973 | 319 | pte_free(mm, new); |
4c21e2f2 | 320 | } else { |
1da177e4 | 321 | mm->nr_ptes++; |
df849a15 | 322 | inc_zone_page_state(new, NR_PAGETABLE); |
1da177e4 LT |
323 | pmd_populate(mm, pmd, new); |
324 | } | |
c74df32c | 325 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 326 | return 0; |
1da177e4 LT |
327 | } |
328 | ||
1bb3630e | 329 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 330 | { |
1bb3630e HD |
331 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
332 | if (!new) | |
333 | return -ENOMEM; | |
334 | ||
335 | spin_lock(&init_mm.page_table_lock); | |
336 | if (pmd_present(*pmd)) /* Another has populated it */ | |
5e541973 | 337 | pte_free_kernel(&init_mm, new); |
1bb3630e HD |
338 | else |
339 | pmd_populate_kernel(&init_mm, pmd, new); | |
340 | spin_unlock(&init_mm.page_table_lock); | |
341 | return 0; | |
1da177e4 LT |
342 | } |
343 | ||
ae859762 HD |
344 | static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) |
345 | { | |
346 | if (file_rss) | |
347 | add_mm_counter(mm, file_rss, file_rss); | |
348 | if (anon_rss) | |
349 | add_mm_counter(mm, anon_rss, anon_rss); | |
350 | } | |
351 | ||
b5810039 | 352 | /* |
6aab341e LT |
353 | * This function is called to print an error when a bad pte |
354 | * is found. For example, we might have a PFN-mapped pte in | |
355 | * a region that doesn't allow it. | |
b5810039 NP |
356 | * |
357 | * The calling function must still handle the error. | |
358 | */ | |
359 | void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) | |
360 | { | |
361 | printk(KERN_ERR "Bad pte = %08llx, process = %s, " | |
362 | "vm_flags = %lx, vaddr = %lx\n", | |
363 | (long long)pte_val(pte), | |
364 | (vma->vm_mm == current->mm ? current->comm : "???"), | |
365 | vma->vm_flags, vaddr); | |
366 | dump_stack(); | |
367 | } | |
368 | ||
67121172 LT |
369 | static inline int is_cow_mapping(unsigned int flags) |
370 | { | |
371 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
372 | } | |
373 | ||
ee498ed7 | 374 | /* |
6aab341e LT |
375 | * This function gets the "struct page" associated with a pte. |
376 | * | |
377 | * NOTE! Some mappings do not have "struct pages". A raw PFN mapping | |
378 | * will have each page table entry just pointing to a raw page frame | |
379 | * number, and as far as the VM layer is concerned, those do not have | |
380 | * pages associated with them - even if the PFN might point to memory | |
381 | * that otherwise is perfectly fine and has a "struct page". | |
382 | * | |
383 | * The way we recognize those mappings is through the rules set up | |
384 | * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set, | |
385 | * and the vm_pgoff will point to the first PFN mapped: thus every | |
386 | * page that is a raw mapping will always honor the rule | |
387 | * | |
388 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
389 | * | |
390 | * and if that isn't true, the page has been COW'ed (in which case it | |
391 | * _does_ have a "struct page" associated with it even if it is in a | |
392 | * VM_PFNMAP range). | |
ee498ed7 | 393 | */ |
6aab341e | 394 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte) |
ee498ed7 | 395 | { |
6aab341e LT |
396 | unsigned long pfn = pte_pfn(pte); |
397 | ||
b7ab795b | 398 | if (unlikely(vma->vm_flags & VM_PFNMAP)) { |
6aab341e LT |
399 | unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT; |
400 | if (pfn == vma->vm_pgoff + off) | |
401 | return NULL; | |
67121172 | 402 | if (!is_cow_mapping(vma->vm_flags)) |
fb155c16 | 403 | return NULL; |
6aab341e LT |
404 | } |
405 | ||
9723198c | 406 | #ifdef CONFIG_DEBUG_VM |
315ab19a NP |
407 | /* |
408 | * Add some anal sanity checks for now. Eventually, | |
409 | * we should just do "return pfn_to_page(pfn)", but | |
410 | * in the meantime we check that we get a valid pfn, | |
411 | * and that the resulting page looks ok. | |
412 | */ | |
6aab341e LT |
413 | if (unlikely(!pfn_valid(pfn))) { |
414 | print_bad_pte(vma, pte, addr); | |
415 | return NULL; | |
416 | } | |
9723198c | 417 | #endif |
6aab341e LT |
418 | |
419 | /* | |
420 | * NOTE! We still have PageReserved() pages in the page | |
421 | * tables. | |
422 | * | |
423 | * The PAGE_ZERO() pages and various VDSO mappings can | |
424 | * cause them to exist. | |
425 | */ | |
426 | return pfn_to_page(pfn); | |
ee498ed7 HD |
427 | } |
428 | ||
1da177e4 LT |
429 | /* |
430 | * copy one vm_area from one task to the other. Assumes the page tables | |
431 | * already present in the new task to be cleared in the whole range | |
432 | * covered by this vma. | |
1da177e4 LT |
433 | */ |
434 | ||
8c103762 | 435 | static inline void |
1da177e4 | 436 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 437 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 438 | unsigned long addr, int *rss) |
1da177e4 | 439 | { |
b5810039 | 440 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
441 | pte_t pte = *src_pte; |
442 | struct page *page; | |
1da177e4 LT |
443 | |
444 | /* pte contains position in swap or file, so copy. */ | |
445 | if (unlikely(!pte_present(pte))) { | |
446 | if (!pte_file(pte)) { | |
0697212a CL |
447 | swp_entry_t entry = pte_to_swp_entry(pte); |
448 | ||
449 | swap_duplicate(entry); | |
1da177e4 LT |
450 | /* make sure dst_mm is on swapoff's mmlist. */ |
451 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
452 | spin_lock(&mmlist_lock); | |
f412ac08 HD |
453 | if (list_empty(&dst_mm->mmlist)) |
454 | list_add(&dst_mm->mmlist, | |
455 | &src_mm->mmlist); | |
1da177e4 LT |
456 | spin_unlock(&mmlist_lock); |
457 | } | |
0697212a CL |
458 | if (is_write_migration_entry(entry) && |
459 | is_cow_mapping(vm_flags)) { | |
460 | /* | |
461 | * COW mappings require pages in both parent | |
462 | * and child to be set to read. | |
463 | */ | |
464 | make_migration_entry_read(&entry); | |
465 | pte = swp_entry_to_pte(entry); | |
466 | set_pte_at(src_mm, addr, src_pte, pte); | |
467 | } | |
1da177e4 | 468 | } |
ae859762 | 469 | goto out_set_pte; |
1da177e4 LT |
470 | } |
471 | ||
1da177e4 LT |
472 | /* |
473 | * If it's a COW mapping, write protect it both | |
474 | * in the parent and the child | |
475 | */ | |
67121172 | 476 | if (is_cow_mapping(vm_flags)) { |
1da177e4 | 477 | ptep_set_wrprotect(src_mm, addr, src_pte); |
3dc90795 | 478 | pte = pte_wrprotect(pte); |
1da177e4 LT |
479 | } |
480 | ||
481 | /* | |
482 | * If it's a shared mapping, mark it clean in | |
483 | * the child | |
484 | */ | |
485 | if (vm_flags & VM_SHARED) | |
486 | pte = pte_mkclean(pte); | |
487 | pte = pte_mkold(pte); | |
6aab341e LT |
488 | |
489 | page = vm_normal_page(vma, addr, pte); | |
490 | if (page) { | |
491 | get_page(page); | |
c97a9e10 | 492 | page_dup_rmap(page, vma, addr); |
6aab341e LT |
493 | rss[!!PageAnon(page)]++; |
494 | } | |
ae859762 HD |
495 | |
496 | out_set_pte: | |
497 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
1da177e4 LT |
498 | } |
499 | ||
500 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
501 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, | |
502 | unsigned long addr, unsigned long end) | |
503 | { | |
504 | pte_t *src_pte, *dst_pte; | |
c74df32c | 505 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 506 | int progress = 0; |
8c103762 | 507 | int rss[2]; |
1da177e4 LT |
508 | |
509 | again: | |
ae859762 | 510 | rss[1] = rss[0] = 0; |
c74df32c | 511 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
512 | if (!dst_pte) |
513 | return -ENOMEM; | |
514 | src_pte = pte_offset_map_nested(src_pmd, addr); | |
4c21e2f2 | 515 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 516 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
6606c3e0 | 517 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 518 | |
1da177e4 LT |
519 | do { |
520 | /* | |
521 | * We are holding two locks at this point - either of them | |
522 | * could generate latencies in another task on another CPU. | |
523 | */ | |
e040f218 HD |
524 | if (progress >= 32) { |
525 | progress = 0; | |
526 | if (need_resched() || | |
95c354fe | 527 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
528 | break; |
529 | } | |
1da177e4 LT |
530 | if (pte_none(*src_pte)) { |
531 | progress++; | |
532 | continue; | |
533 | } | |
8c103762 | 534 | copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); |
1da177e4 LT |
535 | progress += 8; |
536 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 537 | |
6606c3e0 | 538 | arch_leave_lazy_mmu_mode(); |
c74df32c | 539 | spin_unlock(src_ptl); |
1da177e4 | 540 | pte_unmap_nested(src_pte - 1); |
ae859762 | 541 | add_mm_rss(dst_mm, rss[0], rss[1]); |
c74df32c HD |
542 | pte_unmap_unlock(dst_pte - 1, dst_ptl); |
543 | cond_resched(); | |
1da177e4 LT |
544 | if (addr != end) |
545 | goto again; | |
546 | return 0; | |
547 | } | |
548 | ||
549 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
550 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
551 | unsigned long addr, unsigned long end) | |
552 | { | |
553 | pmd_t *src_pmd, *dst_pmd; | |
554 | unsigned long next; | |
555 | ||
556 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
557 | if (!dst_pmd) | |
558 | return -ENOMEM; | |
559 | src_pmd = pmd_offset(src_pud, addr); | |
560 | do { | |
561 | next = pmd_addr_end(addr, end); | |
562 | if (pmd_none_or_clear_bad(src_pmd)) | |
563 | continue; | |
564 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
565 | vma, addr, next)) | |
566 | return -ENOMEM; | |
567 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
568 | return 0; | |
569 | } | |
570 | ||
571 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
572 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
573 | unsigned long addr, unsigned long end) | |
574 | { | |
575 | pud_t *src_pud, *dst_pud; | |
576 | unsigned long next; | |
577 | ||
578 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
579 | if (!dst_pud) | |
580 | return -ENOMEM; | |
581 | src_pud = pud_offset(src_pgd, addr); | |
582 | do { | |
583 | next = pud_addr_end(addr, end); | |
584 | if (pud_none_or_clear_bad(src_pud)) | |
585 | continue; | |
586 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
587 | vma, addr, next)) | |
588 | return -ENOMEM; | |
589 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
590 | return 0; | |
591 | } | |
592 | ||
593 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
594 | struct vm_area_struct *vma) | |
595 | { | |
596 | pgd_t *src_pgd, *dst_pgd; | |
597 | unsigned long next; | |
598 | unsigned long addr = vma->vm_start; | |
599 | unsigned long end = vma->vm_end; | |
600 | ||
d992895b NP |
601 | /* |
602 | * Don't copy ptes where a page fault will fill them correctly. | |
603 | * Fork becomes much lighter when there are big shared or private | |
604 | * readonly mappings. The tradeoff is that copy_page_range is more | |
605 | * efficient than faulting. | |
606 | */ | |
4d7672b4 | 607 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { |
d992895b NP |
608 | if (!vma->anon_vma) |
609 | return 0; | |
610 | } | |
611 | ||
1da177e4 LT |
612 | if (is_vm_hugetlb_page(vma)) |
613 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
614 | ||
615 | dst_pgd = pgd_offset(dst_mm, addr); | |
616 | src_pgd = pgd_offset(src_mm, addr); | |
617 | do { | |
618 | next = pgd_addr_end(addr, end); | |
619 | if (pgd_none_or_clear_bad(src_pgd)) | |
620 | continue; | |
621 | if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, | |
622 | vma, addr, next)) | |
623 | return -ENOMEM; | |
624 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); | |
625 | return 0; | |
626 | } | |
627 | ||
51c6f666 | 628 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 629 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 630 | unsigned long addr, unsigned long end, |
51c6f666 | 631 | long *zap_work, struct zap_details *details) |
1da177e4 | 632 | { |
b5810039 | 633 | struct mm_struct *mm = tlb->mm; |
1da177e4 | 634 | pte_t *pte; |
508034a3 | 635 | spinlock_t *ptl; |
ae859762 HD |
636 | int file_rss = 0; |
637 | int anon_rss = 0; | |
1da177e4 | 638 | |
508034a3 | 639 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
6606c3e0 | 640 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
641 | do { |
642 | pte_t ptent = *pte; | |
51c6f666 RH |
643 | if (pte_none(ptent)) { |
644 | (*zap_work)--; | |
1da177e4 | 645 | continue; |
51c6f666 | 646 | } |
6f5e6b9e HD |
647 | |
648 | (*zap_work) -= PAGE_SIZE; | |
649 | ||
1da177e4 | 650 | if (pte_present(ptent)) { |
ee498ed7 | 651 | struct page *page; |
51c6f666 | 652 | |
6aab341e | 653 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
654 | if (unlikely(details) && page) { |
655 | /* | |
656 | * unmap_shared_mapping_pages() wants to | |
657 | * invalidate cache without truncating: | |
658 | * unmap shared but keep private pages. | |
659 | */ | |
660 | if (details->check_mapping && | |
661 | details->check_mapping != page->mapping) | |
662 | continue; | |
663 | /* | |
664 | * Each page->index must be checked when | |
665 | * invalidating or truncating nonlinear. | |
666 | */ | |
667 | if (details->nonlinear_vma && | |
668 | (page->index < details->first_index || | |
669 | page->index > details->last_index)) | |
670 | continue; | |
671 | } | |
b5810039 | 672 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 673 | tlb->fullmm); |
1da177e4 LT |
674 | tlb_remove_tlb_entry(tlb, pte, addr); |
675 | if (unlikely(!page)) | |
676 | continue; | |
677 | if (unlikely(details) && details->nonlinear_vma | |
678 | && linear_page_index(details->nonlinear_vma, | |
679 | addr) != page->index) | |
b5810039 | 680 | set_pte_at(mm, addr, pte, |
1da177e4 | 681 | pgoff_to_pte(page->index)); |
1da177e4 | 682 | if (PageAnon(page)) |
86d912f4 | 683 | anon_rss--; |
6237bcd9 HD |
684 | else { |
685 | if (pte_dirty(ptent)) | |
686 | set_page_dirty(page); | |
687 | if (pte_young(ptent)) | |
daa88c8d | 688 | SetPageReferenced(page); |
86d912f4 | 689 | file_rss--; |
6237bcd9 | 690 | } |
7de6b805 | 691 | page_remove_rmap(page, vma); |
1da177e4 LT |
692 | tlb_remove_page(tlb, page); |
693 | continue; | |
694 | } | |
695 | /* | |
696 | * If details->check_mapping, we leave swap entries; | |
697 | * if details->nonlinear_vma, we leave file entries. | |
698 | */ | |
699 | if (unlikely(details)) | |
700 | continue; | |
701 | if (!pte_file(ptent)) | |
702 | free_swap_and_cache(pte_to_swp_entry(ptent)); | |
9888a1ca | 703 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); |
51c6f666 | 704 | } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); |
ae859762 | 705 | |
86d912f4 | 706 | add_mm_rss(mm, file_rss, anon_rss); |
6606c3e0 | 707 | arch_leave_lazy_mmu_mode(); |
508034a3 | 708 | pte_unmap_unlock(pte - 1, ptl); |
51c6f666 RH |
709 | |
710 | return addr; | |
1da177e4 LT |
711 | } |
712 | ||
51c6f666 | 713 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 714 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 715 | unsigned long addr, unsigned long end, |
51c6f666 | 716 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
717 | { |
718 | pmd_t *pmd; | |
719 | unsigned long next; | |
720 | ||
721 | pmd = pmd_offset(pud, addr); | |
722 | do { | |
723 | next = pmd_addr_end(addr, end); | |
51c6f666 RH |
724 | if (pmd_none_or_clear_bad(pmd)) { |
725 | (*zap_work)--; | |
1da177e4 | 726 | continue; |
51c6f666 RH |
727 | } |
728 | next = zap_pte_range(tlb, vma, pmd, addr, next, | |
729 | zap_work, details); | |
730 | } while (pmd++, addr = next, (addr != end && *zap_work > 0)); | |
731 | ||
732 | return addr; | |
1da177e4 LT |
733 | } |
734 | ||
51c6f666 | 735 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 736 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 737 | unsigned long addr, unsigned long end, |
51c6f666 | 738 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
739 | { |
740 | pud_t *pud; | |
741 | unsigned long next; | |
742 | ||
743 | pud = pud_offset(pgd, addr); | |
744 | do { | |
745 | next = pud_addr_end(addr, end); | |
51c6f666 RH |
746 | if (pud_none_or_clear_bad(pud)) { |
747 | (*zap_work)--; | |
1da177e4 | 748 | continue; |
51c6f666 RH |
749 | } |
750 | next = zap_pmd_range(tlb, vma, pud, addr, next, | |
751 | zap_work, details); | |
752 | } while (pud++, addr = next, (addr != end && *zap_work > 0)); | |
753 | ||
754 | return addr; | |
1da177e4 LT |
755 | } |
756 | ||
51c6f666 RH |
757 | static unsigned long unmap_page_range(struct mmu_gather *tlb, |
758 | struct vm_area_struct *vma, | |
1da177e4 | 759 | unsigned long addr, unsigned long end, |
51c6f666 | 760 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
761 | { |
762 | pgd_t *pgd; | |
763 | unsigned long next; | |
764 | ||
765 | if (details && !details->check_mapping && !details->nonlinear_vma) | |
766 | details = NULL; | |
767 | ||
768 | BUG_ON(addr >= end); | |
769 | tlb_start_vma(tlb, vma); | |
770 | pgd = pgd_offset(vma->vm_mm, addr); | |
771 | do { | |
772 | next = pgd_addr_end(addr, end); | |
51c6f666 RH |
773 | if (pgd_none_or_clear_bad(pgd)) { |
774 | (*zap_work)--; | |
1da177e4 | 775 | continue; |
51c6f666 RH |
776 | } |
777 | next = zap_pud_range(tlb, vma, pgd, addr, next, | |
778 | zap_work, details); | |
779 | } while (pgd++, addr = next, (addr != end && *zap_work > 0)); | |
1da177e4 | 780 | tlb_end_vma(tlb, vma); |
51c6f666 RH |
781 | |
782 | return addr; | |
1da177e4 LT |
783 | } |
784 | ||
785 | #ifdef CONFIG_PREEMPT | |
786 | # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) | |
787 | #else | |
788 | /* No preempt: go for improved straight-line efficiency */ | |
789 | # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) | |
790 | #endif | |
791 | ||
792 | /** | |
793 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
794 | * @tlbp: address of the caller's struct mmu_gather | |
1da177e4 LT |
795 | * @vma: the starting vma |
796 | * @start_addr: virtual address at which to start unmapping | |
797 | * @end_addr: virtual address at which to end unmapping | |
798 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here | |
799 | * @details: details of nonlinear truncation or shared cache invalidation | |
800 | * | |
ee39b37b | 801 | * Returns the end address of the unmapping (restart addr if interrupted). |
1da177e4 | 802 | * |
508034a3 | 803 | * Unmap all pages in the vma list. |
1da177e4 | 804 | * |
508034a3 HD |
805 | * We aim to not hold locks for too long (for scheduling latency reasons). |
806 | * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to | |
1da177e4 LT |
807 | * return the ending mmu_gather to the caller. |
808 | * | |
809 | * Only addresses between `start' and `end' will be unmapped. | |
810 | * | |
811 | * The VMA list must be sorted in ascending virtual address order. | |
812 | * | |
813 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
814 | * range after unmap_vmas() returns. So the only responsibility here is to | |
815 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
816 | * drops the lock and schedules. | |
817 | */ | |
508034a3 | 818 | unsigned long unmap_vmas(struct mmu_gather **tlbp, |
1da177e4 LT |
819 | struct vm_area_struct *vma, unsigned long start_addr, |
820 | unsigned long end_addr, unsigned long *nr_accounted, | |
821 | struct zap_details *details) | |
822 | { | |
51c6f666 | 823 | long zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
824 | unsigned long tlb_start = 0; /* For tlb_finish_mmu */ |
825 | int tlb_start_valid = 0; | |
ee39b37b | 826 | unsigned long start = start_addr; |
1da177e4 | 827 | spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; |
4d6ddfa9 | 828 | int fullmm = (*tlbp)->fullmm; |
1da177e4 LT |
829 | |
830 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { | |
1da177e4 LT |
831 | unsigned long end; |
832 | ||
833 | start = max(vma->vm_start, start_addr); | |
834 | if (start >= vma->vm_end) | |
835 | continue; | |
836 | end = min(vma->vm_end, end_addr); | |
837 | if (end <= vma->vm_start) | |
838 | continue; | |
839 | ||
840 | if (vma->vm_flags & VM_ACCOUNT) | |
841 | *nr_accounted += (end - start) >> PAGE_SHIFT; | |
842 | ||
1da177e4 | 843 | while (start != end) { |
1da177e4 LT |
844 | if (!tlb_start_valid) { |
845 | tlb_start = start; | |
846 | tlb_start_valid = 1; | |
847 | } | |
848 | ||
51c6f666 | 849 | if (unlikely(is_vm_hugetlb_page(vma))) { |
1da177e4 | 850 | unmap_hugepage_range(vma, start, end); |
51c6f666 RH |
851 | zap_work -= (end - start) / |
852 | (HPAGE_SIZE / PAGE_SIZE); | |
853 | start = end; | |
854 | } else | |
855 | start = unmap_page_range(*tlbp, vma, | |
856 | start, end, &zap_work, details); | |
857 | ||
858 | if (zap_work > 0) { | |
859 | BUG_ON(start != end); | |
860 | break; | |
1da177e4 LT |
861 | } |
862 | ||
1da177e4 LT |
863 | tlb_finish_mmu(*tlbp, tlb_start, start); |
864 | ||
865 | if (need_resched() || | |
95c354fe | 866 | (i_mmap_lock && spin_needbreak(i_mmap_lock))) { |
1da177e4 | 867 | if (i_mmap_lock) { |
508034a3 | 868 | *tlbp = NULL; |
1da177e4 LT |
869 | goto out; |
870 | } | |
1da177e4 | 871 | cond_resched(); |
1da177e4 LT |
872 | } |
873 | ||
508034a3 | 874 | *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); |
1da177e4 | 875 | tlb_start_valid = 0; |
51c6f666 | 876 | zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
877 | } |
878 | } | |
879 | out: | |
ee39b37b | 880 | return start; /* which is now the end (or restart) address */ |
1da177e4 LT |
881 | } |
882 | ||
883 | /** | |
884 | * zap_page_range - remove user pages in a given range | |
885 | * @vma: vm_area_struct holding the applicable pages | |
886 | * @address: starting address of pages to zap | |
887 | * @size: number of bytes to zap | |
888 | * @details: details of nonlinear truncation or shared cache invalidation | |
889 | */ | |
ee39b37b | 890 | unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
891 | unsigned long size, struct zap_details *details) |
892 | { | |
893 | struct mm_struct *mm = vma->vm_mm; | |
894 | struct mmu_gather *tlb; | |
895 | unsigned long end = address + size; | |
896 | unsigned long nr_accounted = 0; | |
897 | ||
1da177e4 | 898 | lru_add_drain(); |
1da177e4 | 899 | tlb = tlb_gather_mmu(mm, 0); |
365e9c87 | 900 | update_hiwater_rss(mm); |
508034a3 HD |
901 | end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); |
902 | if (tlb) | |
903 | tlb_finish_mmu(tlb, address, end); | |
ee39b37b | 904 | return end; |
1da177e4 LT |
905 | } |
906 | ||
907 | /* | |
908 | * Do a quick page-table lookup for a single page. | |
1da177e4 | 909 | */ |
6aab341e | 910 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 911 | unsigned int flags) |
1da177e4 LT |
912 | { |
913 | pgd_t *pgd; | |
914 | pud_t *pud; | |
915 | pmd_t *pmd; | |
916 | pte_t *ptep, pte; | |
deceb6cd | 917 | spinlock_t *ptl; |
1da177e4 | 918 | struct page *page; |
6aab341e | 919 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 920 | |
deceb6cd HD |
921 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
922 | if (!IS_ERR(page)) { | |
923 | BUG_ON(flags & FOLL_GET); | |
924 | goto out; | |
925 | } | |
1da177e4 | 926 | |
deceb6cd | 927 | page = NULL; |
1da177e4 LT |
928 | pgd = pgd_offset(mm, address); |
929 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
deceb6cd | 930 | goto no_page_table; |
1da177e4 LT |
931 | |
932 | pud = pud_offset(pgd, address); | |
933 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
deceb6cd | 934 | goto no_page_table; |
1da177e4 LT |
935 | |
936 | pmd = pmd_offset(pud, address); | |
937 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
deceb6cd HD |
938 | goto no_page_table; |
939 | ||
940 | if (pmd_huge(*pmd)) { | |
941 | BUG_ON(flags & FOLL_GET); | |
942 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); | |
1da177e4 | 943 | goto out; |
deceb6cd | 944 | } |
1da177e4 | 945 | |
deceb6cd | 946 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
947 | if (!ptep) |
948 | goto out; | |
949 | ||
950 | pte = *ptep; | |
deceb6cd HD |
951 | if (!pte_present(pte)) |
952 | goto unlock; | |
953 | if ((flags & FOLL_WRITE) && !pte_write(pte)) | |
954 | goto unlock; | |
6aab341e LT |
955 | page = vm_normal_page(vma, address, pte); |
956 | if (unlikely(!page)) | |
deceb6cd | 957 | goto unlock; |
1da177e4 | 958 | |
deceb6cd HD |
959 | if (flags & FOLL_GET) |
960 | get_page(page); | |
961 | if (flags & FOLL_TOUCH) { | |
962 | if ((flags & FOLL_WRITE) && | |
963 | !pte_dirty(pte) && !PageDirty(page)) | |
964 | set_page_dirty(page); | |
965 | mark_page_accessed(page); | |
966 | } | |
967 | unlock: | |
968 | pte_unmap_unlock(ptep, ptl); | |
1da177e4 | 969 | out: |
deceb6cd | 970 | return page; |
1da177e4 | 971 | |
deceb6cd HD |
972 | no_page_table: |
973 | /* | |
974 | * When core dumping an enormous anonymous area that nobody | |
975 | * has touched so far, we don't want to allocate page tables. | |
976 | */ | |
977 | if (flags & FOLL_ANON) { | |
557ed1fa | 978 | page = ZERO_PAGE(0); |
deceb6cd HD |
979 | if (flags & FOLL_GET) |
980 | get_page(page); | |
981 | BUG_ON(flags & FOLL_WRITE); | |
982 | } | |
983 | return page; | |
1da177e4 LT |
984 | } |
985 | ||
1da177e4 LT |
986 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
987 | unsigned long start, int len, int write, int force, | |
988 | struct page **pages, struct vm_area_struct **vmas) | |
989 | { | |
990 | int i; | |
deceb6cd | 991 | unsigned int vm_flags; |
1da177e4 LT |
992 | |
993 | /* | |
994 | * Require read or write permissions. | |
995 | * If 'force' is set, we only require the "MAY" flags. | |
996 | */ | |
deceb6cd HD |
997 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
998 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 LT |
999 | i = 0; |
1000 | ||
1001 | do { | |
deceb6cd HD |
1002 | struct vm_area_struct *vma; |
1003 | unsigned int foll_flags; | |
1da177e4 LT |
1004 | |
1005 | vma = find_extend_vma(mm, start); | |
1006 | if (!vma && in_gate_area(tsk, start)) { | |
1007 | unsigned long pg = start & PAGE_MASK; | |
1008 | struct vm_area_struct *gate_vma = get_gate_vma(tsk); | |
1009 | pgd_t *pgd; | |
1010 | pud_t *pud; | |
1011 | pmd_t *pmd; | |
1012 | pte_t *pte; | |
1013 | if (write) /* user gate pages are read-only */ | |
1014 | return i ? : -EFAULT; | |
1015 | if (pg > TASK_SIZE) | |
1016 | pgd = pgd_offset_k(pg); | |
1017 | else | |
1018 | pgd = pgd_offset_gate(mm, pg); | |
1019 | BUG_ON(pgd_none(*pgd)); | |
1020 | pud = pud_offset(pgd, pg); | |
1021 | BUG_ON(pud_none(*pud)); | |
1022 | pmd = pmd_offset(pud, pg); | |
690dbe1c HD |
1023 | if (pmd_none(*pmd)) |
1024 | return i ? : -EFAULT; | |
1da177e4 | 1025 | pte = pte_offset_map(pmd, pg); |
690dbe1c HD |
1026 | if (pte_none(*pte)) { |
1027 | pte_unmap(pte); | |
1028 | return i ? : -EFAULT; | |
1029 | } | |
1da177e4 | 1030 | if (pages) { |
fa2a455b | 1031 | struct page *page = vm_normal_page(gate_vma, start, *pte); |
6aab341e LT |
1032 | pages[i] = page; |
1033 | if (page) | |
1034 | get_page(page); | |
1da177e4 LT |
1035 | } |
1036 | pte_unmap(pte); | |
1037 | if (vmas) | |
1038 | vmas[i] = gate_vma; | |
1039 | i++; | |
1040 | start += PAGE_SIZE; | |
1041 | len--; | |
1042 | continue; | |
1043 | } | |
1044 | ||
1ff80389 | 1045 | if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) |
deceb6cd | 1046 | || !(vm_flags & vma->vm_flags)) |
1da177e4 LT |
1047 | return i ? : -EFAULT; |
1048 | ||
1049 | if (is_vm_hugetlb_page(vma)) { | |
1050 | i = follow_hugetlb_page(mm, vma, pages, vmas, | |
5b23dbe8 | 1051 | &start, &len, i, write); |
1da177e4 LT |
1052 | continue; |
1053 | } | |
deceb6cd HD |
1054 | |
1055 | foll_flags = FOLL_TOUCH; | |
1056 | if (pages) | |
1057 | foll_flags |= FOLL_GET; | |
1058 | if (!write && !(vma->vm_flags & VM_LOCKED) && | |
54cb8821 NP |
1059 | (!vma->vm_ops || (!vma->vm_ops->nopage && |
1060 | !vma->vm_ops->fault))) | |
deceb6cd HD |
1061 | foll_flags |= FOLL_ANON; |
1062 | ||
1da177e4 | 1063 | do { |
08ef4729 | 1064 | struct page *page; |
1da177e4 | 1065 | |
462e00cc ES |
1066 | /* |
1067 | * If tsk is ooming, cut off its access to large memory | |
1068 | * allocations. It has a pending SIGKILL, but it can't | |
1069 | * be processed until returning to user space. | |
1070 | */ | |
1071 | if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE))) | |
1072 | return -ENOMEM; | |
1073 | ||
deceb6cd HD |
1074 | if (write) |
1075 | foll_flags |= FOLL_WRITE; | |
a68d2ebc | 1076 | |
deceb6cd | 1077 | cond_resched(); |
6aab341e | 1078 | while (!(page = follow_page(vma, start, foll_flags))) { |
deceb6cd | 1079 | int ret; |
83c54070 | 1080 | ret = handle_mm_fault(mm, vma, start, |
deceb6cd | 1081 | foll_flags & FOLL_WRITE); |
83c54070 NP |
1082 | if (ret & VM_FAULT_ERROR) { |
1083 | if (ret & VM_FAULT_OOM) | |
1084 | return i ? i : -ENOMEM; | |
1085 | else if (ret & VM_FAULT_SIGBUS) | |
1086 | return i ? i : -EFAULT; | |
1087 | BUG(); | |
1088 | } | |
1089 | if (ret & VM_FAULT_MAJOR) | |
1090 | tsk->maj_flt++; | |
1091 | else | |
1092 | tsk->min_flt++; | |
1093 | ||
a68d2ebc | 1094 | /* |
83c54070 NP |
1095 | * The VM_FAULT_WRITE bit tells us that |
1096 | * do_wp_page has broken COW when necessary, | |
1097 | * even if maybe_mkwrite decided not to set | |
1098 | * pte_write. We can thus safely do subsequent | |
1099 | * page lookups as if they were reads. | |
a68d2ebc LT |
1100 | */ |
1101 | if (ret & VM_FAULT_WRITE) | |
deceb6cd | 1102 | foll_flags &= ~FOLL_WRITE; |
83c54070 | 1103 | |
7f7bbbe5 | 1104 | cond_resched(); |
1da177e4 LT |
1105 | } |
1106 | if (pages) { | |
08ef4729 | 1107 | pages[i] = page; |
03beb076 | 1108 | |
a6f36be3 | 1109 | flush_anon_page(vma, page, start); |
08ef4729 | 1110 | flush_dcache_page(page); |
1da177e4 LT |
1111 | } |
1112 | if (vmas) | |
1113 | vmas[i] = vma; | |
1114 | i++; | |
1115 | start += PAGE_SIZE; | |
1116 | len--; | |
08ef4729 | 1117 | } while (len && start < vma->vm_end); |
08ef4729 | 1118 | } while (len); |
1da177e4 LT |
1119 | return i; |
1120 | } | |
1da177e4 LT |
1121 | EXPORT_SYMBOL(get_user_pages); |
1122 | ||
920c7a5d HH |
1123 | pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, |
1124 | spinlock_t **ptl) | |
c9cfcddf LT |
1125 | { |
1126 | pgd_t * pgd = pgd_offset(mm, addr); | |
1127 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
1128 | if (pud) { | |
49c91fb0 | 1129 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
c9cfcddf LT |
1130 | if (pmd) |
1131 | return pte_alloc_map_lock(mm, pmd, addr, ptl); | |
1132 | } | |
1133 | return NULL; | |
1134 | } | |
1135 | ||
238f58d8 LT |
1136 | /* |
1137 | * This is the old fallback for page remapping. | |
1138 | * | |
1139 | * For historical reasons, it only allows reserved pages. Only | |
1140 | * old drivers should use this, and they needed to mark their | |
1141 | * pages reserved for the old functions anyway. | |
1142 | */ | |
1143 | static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot) | |
1144 | { | |
1145 | int retval; | |
c9cfcddf | 1146 | pte_t *pte; |
238f58d8 LT |
1147 | spinlock_t *ptl; |
1148 | ||
1149 | retval = -EINVAL; | |
a145dd41 | 1150 | if (PageAnon(page)) |
238f58d8 LT |
1151 | goto out; |
1152 | retval = -ENOMEM; | |
1153 | flush_dcache_page(page); | |
c9cfcddf | 1154 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 LT |
1155 | if (!pte) |
1156 | goto out; | |
1157 | retval = -EBUSY; | |
1158 | if (!pte_none(*pte)) | |
1159 | goto out_unlock; | |
1160 | ||
1161 | /* Ok, finally just insert the thing.. */ | |
1162 | get_page(page); | |
1163 | inc_mm_counter(mm, file_rss); | |
1164 | page_add_file_rmap(page); | |
1165 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); | |
1166 | ||
1167 | retval = 0; | |
1168 | out_unlock: | |
1169 | pte_unmap_unlock(pte, ptl); | |
1170 | out: | |
1171 | return retval; | |
1172 | } | |
1173 | ||
bfa5bf6d REB |
1174 | /** |
1175 | * vm_insert_page - insert single page into user vma | |
1176 | * @vma: user vma to map to | |
1177 | * @addr: target user address of this page | |
1178 | * @page: source kernel page | |
1179 | * | |
a145dd41 LT |
1180 | * This allows drivers to insert individual pages they've allocated |
1181 | * into a user vma. | |
1182 | * | |
1183 | * The page has to be a nice clean _individual_ kernel allocation. | |
1184 | * If you allocate a compound page, you need to have marked it as | |
1185 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 1186 | * (see split_page()). |
a145dd41 LT |
1187 | * |
1188 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
1189 | * took an arbitrary page protection parameter. This doesn't allow | |
1190 | * that. Your vma protection will have to be set up correctly, which | |
1191 | * means that if you want a shared writable mapping, you'd better | |
1192 | * ask for a shared writable mapping! | |
1193 | * | |
1194 | * The page does not need to be reserved. | |
1195 | */ | |
1196 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page) | |
1197 | { | |
1198 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1199 | return -EFAULT; | |
1200 | if (!page_count(page)) | |
1201 | return -EINVAL; | |
4d7672b4 | 1202 | vma->vm_flags |= VM_INSERTPAGE; |
a145dd41 LT |
1203 | return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot); |
1204 | } | |
e3c3374f | 1205 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 1206 | |
e0dc0d8f NP |
1207 | /** |
1208 | * vm_insert_pfn - insert single pfn into user vma | |
1209 | * @vma: user vma to map to | |
1210 | * @addr: target user address of this page | |
1211 | * @pfn: source kernel pfn | |
1212 | * | |
1213 | * Similar to vm_inert_page, this allows drivers to insert individual pages | |
1214 | * they've allocated into a user vma. Same comments apply. | |
1215 | * | |
1216 | * This function should only be called from a vm_ops->fault handler, and | |
1217 | * in that case the handler should return NULL. | |
1218 | */ | |
1219 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
1220 | unsigned long pfn) | |
1221 | { | |
1222 | struct mm_struct *mm = vma->vm_mm; | |
1223 | int retval; | |
1224 | pte_t *pte, entry; | |
1225 | spinlock_t *ptl; | |
1226 | ||
1227 | BUG_ON(!(vma->vm_flags & VM_PFNMAP)); | |
1228 | BUG_ON(is_cow_mapping(vma->vm_flags)); | |
1229 | ||
1230 | retval = -ENOMEM; | |
1231 | pte = get_locked_pte(mm, addr, &ptl); | |
1232 | if (!pte) | |
1233 | goto out; | |
1234 | retval = -EBUSY; | |
1235 | if (!pte_none(*pte)) | |
1236 | goto out_unlock; | |
1237 | ||
1238 | /* Ok, finally just insert the thing.. */ | |
1239 | entry = pfn_pte(pfn, vma->vm_page_prot); | |
1240 | set_pte_at(mm, addr, pte, entry); | |
1241 | update_mmu_cache(vma, addr, entry); | |
1242 | ||
1243 | retval = 0; | |
1244 | out_unlock: | |
1245 | pte_unmap_unlock(pte, ptl); | |
1246 | ||
1247 | out: | |
1248 | return retval; | |
1249 | } | |
1250 | EXPORT_SYMBOL(vm_insert_pfn); | |
1251 | ||
1da177e4 LT |
1252 | /* |
1253 | * maps a range of physical memory into the requested pages. the old | |
1254 | * mappings are removed. any references to nonexistent pages results | |
1255 | * in null mappings (currently treated as "copy-on-access") | |
1256 | */ | |
1257 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
1258 | unsigned long addr, unsigned long end, | |
1259 | unsigned long pfn, pgprot_t prot) | |
1260 | { | |
1261 | pte_t *pte; | |
c74df32c | 1262 | spinlock_t *ptl; |
1da177e4 | 1263 | |
c74df32c | 1264 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
1265 | if (!pte) |
1266 | return -ENOMEM; | |
6606c3e0 | 1267 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1268 | do { |
1269 | BUG_ON(!pte_none(*pte)); | |
b5810039 | 1270 | set_pte_at(mm, addr, pte, pfn_pte(pfn, prot)); |
1da177e4 LT |
1271 | pfn++; |
1272 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 1273 | arch_leave_lazy_mmu_mode(); |
c74df32c | 1274 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
1275 | return 0; |
1276 | } | |
1277 | ||
1278 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1279 | unsigned long addr, unsigned long end, | |
1280 | unsigned long pfn, pgprot_t prot) | |
1281 | { | |
1282 | pmd_t *pmd; | |
1283 | unsigned long next; | |
1284 | ||
1285 | pfn -= addr >> PAGE_SHIFT; | |
1286 | pmd = pmd_alloc(mm, pud, addr); | |
1287 | if (!pmd) | |
1288 | return -ENOMEM; | |
1289 | do { | |
1290 | next = pmd_addr_end(addr, end); | |
1291 | if (remap_pte_range(mm, pmd, addr, next, | |
1292 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1293 | return -ENOMEM; | |
1294 | } while (pmd++, addr = next, addr != end); | |
1295 | return 0; | |
1296 | } | |
1297 | ||
1298 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1299 | unsigned long addr, unsigned long end, | |
1300 | unsigned long pfn, pgprot_t prot) | |
1301 | { | |
1302 | pud_t *pud; | |
1303 | unsigned long next; | |
1304 | ||
1305 | pfn -= addr >> PAGE_SHIFT; | |
1306 | pud = pud_alloc(mm, pgd, addr); | |
1307 | if (!pud) | |
1308 | return -ENOMEM; | |
1309 | do { | |
1310 | next = pud_addr_end(addr, end); | |
1311 | if (remap_pmd_range(mm, pud, addr, next, | |
1312 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1313 | return -ENOMEM; | |
1314 | } while (pud++, addr = next, addr != end); | |
1315 | return 0; | |
1316 | } | |
1317 | ||
bfa5bf6d REB |
1318 | /** |
1319 | * remap_pfn_range - remap kernel memory to userspace | |
1320 | * @vma: user vma to map to | |
1321 | * @addr: target user address to start at | |
1322 | * @pfn: physical address of kernel memory | |
1323 | * @size: size of map area | |
1324 | * @prot: page protection flags for this mapping | |
1325 | * | |
1326 | * Note: this is only safe if the mm semaphore is held when called. | |
1327 | */ | |
1da177e4 LT |
1328 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
1329 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
1330 | { | |
1331 | pgd_t *pgd; | |
1332 | unsigned long next; | |
2d15cab8 | 1333 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 LT |
1334 | struct mm_struct *mm = vma->vm_mm; |
1335 | int err; | |
1336 | ||
1337 | /* | |
1338 | * Physically remapped pages are special. Tell the | |
1339 | * rest of the world about it: | |
1340 | * VM_IO tells people not to look at these pages | |
1341 | * (accesses can have side effects). | |
0b14c179 HD |
1342 | * VM_RESERVED is specified all over the place, because |
1343 | * in 2.4 it kept swapout's vma scan off this vma; but | |
1344 | * in 2.6 the LRU scan won't even find its pages, so this | |
1345 | * flag means no more than count its pages in reserved_vm, | |
1346 | * and omit it from core dump, even when VM_IO turned off. | |
6aab341e LT |
1347 | * VM_PFNMAP tells the core MM that the base pages are just |
1348 | * raw PFN mappings, and do not have a "struct page" associated | |
1349 | * with them. | |
fb155c16 LT |
1350 | * |
1351 | * There's a horrible special case to handle copy-on-write | |
1352 | * behaviour that some programs depend on. We mark the "original" | |
1353 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
1da177e4 | 1354 | */ |
67121172 | 1355 | if (is_cow_mapping(vma->vm_flags)) { |
fb155c16 | 1356 | if (addr != vma->vm_start || end != vma->vm_end) |
7fc7e2ee | 1357 | return -EINVAL; |
fb155c16 LT |
1358 | vma->vm_pgoff = pfn; |
1359 | } | |
1360 | ||
6aab341e | 1361 | vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; |
1da177e4 LT |
1362 | |
1363 | BUG_ON(addr >= end); | |
1364 | pfn -= addr >> PAGE_SHIFT; | |
1365 | pgd = pgd_offset(mm, addr); | |
1366 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
1367 | do { |
1368 | next = pgd_addr_end(addr, end); | |
1369 | err = remap_pud_range(mm, pgd, addr, next, | |
1370 | pfn + (addr >> PAGE_SHIFT), prot); | |
1371 | if (err) | |
1372 | break; | |
1373 | } while (pgd++, addr = next, addr != end); | |
1da177e4 LT |
1374 | return err; |
1375 | } | |
1376 | EXPORT_SYMBOL(remap_pfn_range); | |
1377 | ||
aee16b3c JF |
1378 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
1379 | unsigned long addr, unsigned long end, | |
1380 | pte_fn_t fn, void *data) | |
1381 | { | |
1382 | pte_t *pte; | |
1383 | int err; | |
1384 | struct page *pmd_page; | |
94909914 | 1385 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
1386 | |
1387 | pte = (mm == &init_mm) ? | |
1388 | pte_alloc_kernel(pmd, addr) : | |
1389 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
1390 | if (!pte) | |
1391 | return -ENOMEM; | |
1392 | ||
1393 | BUG_ON(pmd_huge(*pmd)); | |
1394 | ||
1395 | pmd_page = pmd_page(*pmd); | |
1396 | ||
1397 | do { | |
1398 | err = fn(pte, pmd_page, addr, data); | |
1399 | if (err) | |
1400 | break; | |
1401 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
1402 | ||
1403 | if (mm != &init_mm) | |
1404 | pte_unmap_unlock(pte-1, ptl); | |
1405 | return err; | |
1406 | } | |
1407 | ||
1408 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1409 | unsigned long addr, unsigned long end, | |
1410 | pte_fn_t fn, void *data) | |
1411 | { | |
1412 | pmd_t *pmd; | |
1413 | unsigned long next; | |
1414 | int err; | |
1415 | ||
1416 | pmd = pmd_alloc(mm, pud, addr); | |
1417 | if (!pmd) | |
1418 | return -ENOMEM; | |
1419 | do { | |
1420 | next = pmd_addr_end(addr, end); | |
1421 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
1422 | if (err) | |
1423 | break; | |
1424 | } while (pmd++, addr = next, addr != end); | |
1425 | return err; | |
1426 | } | |
1427 | ||
1428 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1429 | unsigned long addr, unsigned long end, | |
1430 | pte_fn_t fn, void *data) | |
1431 | { | |
1432 | pud_t *pud; | |
1433 | unsigned long next; | |
1434 | int err; | |
1435 | ||
1436 | pud = pud_alloc(mm, pgd, addr); | |
1437 | if (!pud) | |
1438 | return -ENOMEM; | |
1439 | do { | |
1440 | next = pud_addr_end(addr, end); | |
1441 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
1442 | if (err) | |
1443 | break; | |
1444 | } while (pud++, addr = next, addr != end); | |
1445 | return err; | |
1446 | } | |
1447 | ||
1448 | /* | |
1449 | * Scan a region of virtual memory, filling in page tables as necessary | |
1450 | * and calling a provided function on each leaf page table. | |
1451 | */ | |
1452 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
1453 | unsigned long size, pte_fn_t fn, void *data) | |
1454 | { | |
1455 | pgd_t *pgd; | |
1456 | unsigned long next; | |
1457 | unsigned long end = addr + size; | |
1458 | int err; | |
1459 | ||
1460 | BUG_ON(addr >= end); | |
1461 | pgd = pgd_offset(mm, addr); | |
1462 | do { | |
1463 | next = pgd_addr_end(addr, end); | |
1464 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
1465 | if (err) | |
1466 | break; | |
1467 | } while (pgd++, addr = next, addr != end); | |
1468 | return err; | |
1469 | } | |
1470 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
1471 | ||
8f4e2101 HD |
1472 | /* |
1473 | * handle_pte_fault chooses page fault handler according to an entry | |
1474 | * which was read non-atomically. Before making any commitment, on | |
1475 | * those architectures or configurations (e.g. i386 with PAE) which | |
1476 | * might give a mix of unmatched parts, do_swap_page and do_file_page | |
1477 | * must check under lock before unmapping the pte and proceeding | |
1478 | * (but do_wp_page is only called after already making such a check; | |
1479 | * and do_anonymous_page and do_no_page can safely check later on). | |
1480 | */ | |
4c21e2f2 | 1481 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
1482 | pte_t *page_table, pte_t orig_pte) |
1483 | { | |
1484 | int same = 1; | |
1485 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
1486 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
1487 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
1488 | spin_lock(ptl); | |
8f4e2101 | 1489 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 1490 | spin_unlock(ptl); |
8f4e2101 HD |
1491 | } |
1492 | #endif | |
1493 | pte_unmap(page_table); | |
1494 | return same; | |
1495 | } | |
1496 | ||
1da177e4 LT |
1497 | /* |
1498 | * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when | |
1499 | * servicing faults for write access. In the normal case, do always want | |
1500 | * pte_mkwrite. But get_user_pages can cause write faults for mappings | |
1501 | * that do not have writing enabled, when used by access_process_vm. | |
1502 | */ | |
1503 | static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) | |
1504 | { | |
1505 | if (likely(vma->vm_flags & VM_WRITE)) | |
1506 | pte = pte_mkwrite(pte); | |
1507 | return pte; | |
1508 | } | |
1509 | ||
9de455b2 | 1510 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e LT |
1511 | { |
1512 | /* | |
1513 | * If the source page was a PFN mapping, we don't have | |
1514 | * a "struct page" for it. We do a best-effort copy by | |
1515 | * just copying from the original user address. If that | |
1516 | * fails, we just zero-fill it. Live with it. | |
1517 | */ | |
1518 | if (unlikely(!src)) { | |
1519 | void *kaddr = kmap_atomic(dst, KM_USER0); | |
5d2a2dbb LT |
1520 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
1521 | ||
1522 | /* | |
1523 | * This really shouldn't fail, because the page is there | |
1524 | * in the page tables. But it might just be unreadable, | |
1525 | * in which case we just give up and fill the result with | |
1526 | * zeroes. | |
1527 | */ | |
1528 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
6aab341e LT |
1529 | memset(kaddr, 0, PAGE_SIZE); |
1530 | kunmap_atomic(kaddr, KM_USER0); | |
c4ec7b0d | 1531 | flush_dcache_page(dst); |
0ed361de NP |
1532 | } else |
1533 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
1534 | } |
1535 | ||
1da177e4 LT |
1536 | /* |
1537 | * This routine handles present pages, when users try to write | |
1538 | * to a shared page. It is done by copying the page to a new address | |
1539 | * and decrementing the shared-page counter for the old page. | |
1540 | * | |
1da177e4 LT |
1541 | * Note that this routine assumes that the protection checks have been |
1542 | * done by the caller (the low-level page fault routine in most cases). | |
1543 | * Thus we can safely just mark it writable once we've done any necessary | |
1544 | * COW. | |
1545 | * | |
1546 | * We also mark the page dirty at this point even though the page will | |
1547 | * change only once the write actually happens. This avoids a few races, | |
1548 | * and potentially makes it more efficient. | |
1549 | * | |
8f4e2101 HD |
1550 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
1551 | * but allow concurrent faults), with pte both mapped and locked. | |
1552 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 1553 | */ |
65500d23 HD |
1554 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1555 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
8f4e2101 | 1556 | spinlock_t *ptl, pte_t orig_pte) |
1da177e4 | 1557 | { |
e5bbe4df | 1558 | struct page *old_page, *new_page; |
1da177e4 | 1559 | pte_t entry; |
83c54070 | 1560 | int reuse = 0, ret = 0; |
a200ee18 | 1561 | int page_mkwrite = 0; |
d08b3851 | 1562 | struct page *dirty_page = NULL; |
1da177e4 | 1563 | |
6aab341e | 1564 | old_page = vm_normal_page(vma, address, orig_pte); |
6aab341e LT |
1565 | if (!old_page) |
1566 | goto gotten; | |
1da177e4 | 1567 | |
d08b3851 | 1568 | /* |
ee6a6457 PZ |
1569 | * Take out anonymous pages first, anonymous shared vmas are |
1570 | * not dirty accountable. | |
d08b3851 | 1571 | */ |
ee6a6457 PZ |
1572 | if (PageAnon(old_page)) { |
1573 | if (!TestSetPageLocked(old_page)) { | |
1574 | reuse = can_share_swap_page(old_page); | |
1575 | unlock_page(old_page); | |
1576 | } | |
1577 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
d08b3851 | 1578 | (VM_WRITE|VM_SHARED))) { |
ee6a6457 PZ |
1579 | /* |
1580 | * Only catch write-faults on shared writable pages, | |
1581 | * read-only shared pages can get COWed by | |
1582 | * get_user_pages(.write=1, .force=1). | |
1583 | */ | |
9637a5ef DH |
1584 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
1585 | /* | |
1586 | * Notify the address space that the page is about to | |
1587 | * become writable so that it can prohibit this or wait | |
1588 | * for the page to get into an appropriate state. | |
1589 | * | |
1590 | * We do this without the lock held, so that it can | |
1591 | * sleep if it needs to. | |
1592 | */ | |
1593 | page_cache_get(old_page); | |
1594 | pte_unmap_unlock(page_table, ptl); | |
1595 | ||
1596 | if (vma->vm_ops->page_mkwrite(vma, old_page) < 0) | |
1597 | goto unwritable_page; | |
1598 | ||
9637a5ef DH |
1599 | /* |
1600 | * Since we dropped the lock we need to revalidate | |
1601 | * the PTE as someone else may have changed it. If | |
1602 | * they did, we just return, as we can count on the | |
1603 | * MMU to tell us if they didn't also make it writable. | |
1604 | */ | |
1605 | page_table = pte_offset_map_lock(mm, pmd, address, | |
1606 | &ptl); | |
c3704ceb | 1607 | page_cache_release(old_page); |
9637a5ef DH |
1608 | if (!pte_same(*page_table, orig_pte)) |
1609 | goto unlock; | |
a200ee18 PZ |
1610 | |
1611 | page_mkwrite = 1; | |
1da177e4 | 1612 | } |
d08b3851 PZ |
1613 | dirty_page = old_page; |
1614 | get_page(dirty_page); | |
9637a5ef | 1615 | reuse = 1; |
9637a5ef DH |
1616 | } |
1617 | ||
1618 | if (reuse) { | |
1619 | flush_cache_page(vma, address, pte_pfn(orig_pte)); | |
1620 | entry = pte_mkyoung(orig_pte); | |
1621 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
954ffcb3 | 1622 | if (ptep_set_access_flags(vma, address, page_table, entry,1)) |
8dab5241 | 1623 | update_mmu_cache(vma, address, entry); |
9637a5ef DH |
1624 | ret |= VM_FAULT_WRITE; |
1625 | goto unlock; | |
1da177e4 | 1626 | } |
1da177e4 LT |
1627 | |
1628 | /* | |
1629 | * Ok, we need to copy. Oh, well.. | |
1630 | */ | |
b5810039 | 1631 | page_cache_get(old_page); |
920fc356 | 1632 | gotten: |
8f4e2101 | 1633 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
1634 | |
1635 | if (unlikely(anon_vma_prepare(vma))) | |
65500d23 | 1636 | goto oom; |
557ed1fa NP |
1637 | VM_BUG_ON(old_page == ZERO_PAGE(0)); |
1638 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
1639 | if (!new_page) | |
1640 | goto oom; | |
1641 | cow_user_page(new_page, old_page, address, vma); | |
0ed361de | 1642 | __SetPageUptodate(new_page); |
65500d23 | 1643 | |
1da177e4 LT |
1644 | /* |
1645 | * Re-check the pte - we dropped the lock | |
1646 | */ | |
8f4e2101 | 1647 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
65500d23 | 1648 | if (likely(pte_same(*page_table, orig_pte))) { |
920fc356 | 1649 | if (old_page) { |
7de6b805 | 1650 | page_remove_rmap(old_page, vma); |
920fc356 HD |
1651 | if (!PageAnon(old_page)) { |
1652 | dec_mm_counter(mm, file_rss); | |
1653 | inc_mm_counter(mm, anon_rss); | |
1654 | } | |
1655 | } else | |
4294621f | 1656 | inc_mm_counter(mm, anon_rss); |
eca35133 | 1657 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
65500d23 HD |
1658 | entry = mk_pte(new_page, vma->vm_page_prot); |
1659 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
4ce072f1 SS |
1660 | /* |
1661 | * Clear the pte entry and flush it first, before updating the | |
1662 | * pte with the new entry. This will avoid a race condition | |
1663 | * seen in the presence of one thread doing SMC and another | |
1664 | * thread doing COW. | |
1665 | */ | |
1666 | ptep_clear_flush(vma, address, page_table); | |
1667 | set_pte_at(mm, address, page_table, entry); | |
65500d23 | 1668 | update_mmu_cache(vma, address, entry); |
1da177e4 | 1669 | lru_cache_add_active(new_page); |
9617d95e | 1670 | page_add_new_anon_rmap(new_page, vma, address); |
1da177e4 LT |
1671 | |
1672 | /* Free the old page.. */ | |
1673 | new_page = old_page; | |
f33ea7f4 | 1674 | ret |= VM_FAULT_WRITE; |
1da177e4 | 1675 | } |
920fc356 HD |
1676 | if (new_page) |
1677 | page_cache_release(new_page); | |
1678 | if (old_page) | |
1679 | page_cache_release(old_page); | |
65500d23 | 1680 | unlock: |
8f4e2101 | 1681 | pte_unmap_unlock(page_table, ptl); |
d08b3851 | 1682 | if (dirty_page) { |
8f7b3d15 AS |
1683 | if (vma->vm_file) |
1684 | file_update_time(vma->vm_file); | |
1685 | ||
79352894 NP |
1686 | /* |
1687 | * Yes, Virginia, this is actually required to prevent a race | |
1688 | * with clear_page_dirty_for_io() from clearing the page dirty | |
1689 | * bit after it clear all dirty ptes, but before a racing | |
1690 | * do_wp_page installs a dirty pte. | |
1691 | * | |
1692 | * do_no_page is protected similarly. | |
1693 | */ | |
1694 | wait_on_page_locked(dirty_page); | |
a200ee18 | 1695 | set_page_dirty_balance(dirty_page, page_mkwrite); |
d08b3851 PZ |
1696 | put_page(dirty_page); |
1697 | } | |
f33ea7f4 | 1698 | return ret; |
65500d23 | 1699 | oom: |
920fc356 HD |
1700 | if (old_page) |
1701 | page_cache_release(old_page); | |
1da177e4 | 1702 | return VM_FAULT_OOM; |
9637a5ef DH |
1703 | |
1704 | unwritable_page: | |
1705 | page_cache_release(old_page); | |
1706 | return VM_FAULT_SIGBUS; | |
1da177e4 LT |
1707 | } |
1708 | ||
1709 | /* | |
1710 | * Helper functions for unmap_mapping_range(). | |
1711 | * | |
1712 | * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ | |
1713 | * | |
1714 | * We have to restart searching the prio_tree whenever we drop the lock, | |
1715 | * since the iterator is only valid while the lock is held, and anyway | |
1716 | * a later vma might be split and reinserted earlier while lock dropped. | |
1717 | * | |
1718 | * The list of nonlinear vmas could be handled more efficiently, using | |
1719 | * a placeholder, but handle it in the same way until a need is shown. | |
1720 | * It is important to search the prio_tree before nonlinear list: a vma | |
1721 | * may become nonlinear and be shifted from prio_tree to nonlinear list | |
1722 | * while the lock is dropped; but never shifted from list to prio_tree. | |
1723 | * | |
1724 | * In order to make forward progress despite restarting the search, | |
1725 | * vm_truncate_count is used to mark a vma as now dealt with, so we can | |
1726 | * quickly skip it next time around. Since the prio_tree search only | |
1727 | * shows us those vmas affected by unmapping the range in question, we | |
1728 | * can't efficiently keep all vmas in step with mapping->truncate_count: | |
1729 | * so instead reset them all whenever it wraps back to 0 (then go to 1). | |
1730 | * mapping->truncate_count and vma->vm_truncate_count are protected by | |
1731 | * i_mmap_lock. | |
1732 | * | |
1733 | * In order to make forward progress despite repeatedly restarting some | |
ee39b37b | 1734 | * large vma, note the restart_addr from unmap_vmas when it breaks out: |
1da177e4 LT |
1735 | * and restart from that address when we reach that vma again. It might |
1736 | * have been split or merged, shrunk or extended, but never shifted: so | |
1737 | * restart_addr remains valid so long as it remains in the vma's range. | |
1738 | * unmap_mapping_range forces truncate_count to leap over page-aligned | |
1739 | * values so we can save vma's restart_addr in its truncate_count field. | |
1740 | */ | |
1741 | #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) | |
1742 | ||
1743 | static void reset_vma_truncate_counts(struct address_space *mapping) | |
1744 | { | |
1745 | struct vm_area_struct *vma; | |
1746 | struct prio_tree_iter iter; | |
1747 | ||
1748 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) | |
1749 | vma->vm_truncate_count = 0; | |
1750 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) | |
1751 | vma->vm_truncate_count = 0; | |
1752 | } | |
1753 | ||
1754 | static int unmap_mapping_range_vma(struct vm_area_struct *vma, | |
1755 | unsigned long start_addr, unsigned long end_addr, | |
1756 | struct zap_details *details) | |
1757 | { | |
1758 | unsigned long restart_addr; | |
1759 | int need_break; | |
1760 | ||
d00806b1 NP |
1761 | /* |
1762 | * files that support invalidating or truncating portions of the | |
d0217ac0 | 1763 | * file from under mmaped areas must have their ->fault function |
83c54070 NP |
1764 | * return a locked page (and set VM_FAULT_LOCKED in the return). |
1765 | * This provides synchronisation against concurrent unmapping here. | |
d00806b1 | 1766 | */ |
d00806b1 | 1767 | |
1da177e4 LT |
1768 | again: |
1769 | restart_addr = vma->vm_truncate_count; | |
1770 | if (is_restart_addr(restart_addr) && start_addr < restart_addr) { | |
1771 | start_addr = restart_addr; | |
1772 | if (start_addr >= end_addr) { | |
1773 | /* Top of vma has been split off since last time */ | |
1774 | vma->vm_truncate_count = details->truncate_count; | |
1775 | return 0; | |
1776 | } | |
1777 | } | |
1778 | ||
ee39b37b HD |
1779 | restart_addr = zap_page_range(vma, start_addr, |
1780 | end_addr - start_addr, details); | |
95c354fe | 1781 | need_break = need_resched() || spin_needbreak(details->i_mmap_lock); |
1da177e4 | 1782 | |
ee39b37b | 1783 | if (restart_addr >= end_addr) { |
1da177e4 LT |
1784 | /* We have now completed this vma: mark it so */ |
1785 | vma->vm_truncate_count = details->truncate_count; | |
1786 | if (!need_break) | |
1787 | return 0; | |
1788 | } else { | |
1789 | /* Note restart_addr in vma's truncate_count field */ | |
ee39b37b | 1790 | vma->vm_truncate_count = restart_addr; |
1da177e4 LT |
1791 | if (!need_break) |
1792 | goto again; | |
1793 | } | |
1794 | ||
1795 | spin_unlock(details->i_mmap_lock); | |
1796 | cond_resched(); | |
1797 | spin_lock(details->i_mmap_lock); | |
1798 | return -EINTR; | |
1799 | } | |
1800 | ||
1801 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, | |
1802 | struct zap_details *details) | |
1803 | { | |
1804 | struct vm_area_struct *vma; | |
1805 | struct prio_tree_iter iter; | |
1806 | pgoff_t vba, vea, zba, zea; | |
1807 | ||
1808 | restart: | |
1809 | vma_prio_tree_foreach(vma, &iter, root, | |
1810 | details->first_index, details->last_index) { | |
1811 | /* Skip quickly over those we have already dealt with */ | |
1812 | if (vma->vm_truncate_count == details->truncate_count) | |
1813 | continue; | |
1814 | ||
1815 | vba = vma->vm_pgoff; | |
1816 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; | |
1817 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ | |
1818 | zba = details->first_index; | |
1819 | if (zba < vba) | |
1820 | zba = vba; | |
1821 | zea = details->last_index; | |
1822 | if (zea > vea) | |
1823 | zea = vea; | |
1824 | ||
1825 | if (unmap_mapping_range_vma(vma, | |
1826 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, | |
1827 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
1828 | details) < 0) | |
1829 | goto restart; | |
1830 | } | |
1831 | } | |
1832 | ||
1833 | static inline void unmap_mapping_range_list(struct list_head *head, | |
1834 | struct zap_details *details) | |
1835 | { | |
1836 | struct vm_area_struct *vma; | |
1837 | ||
1838 | /* | |
1839 | * In nonlinear VMAs there is no correspondence between virtual address | |
1840 | * offset and file offset. So we must perform an exhaustive search | |
1841 | * across *all* the pages in each nonlinear VMA, not just the pages | |
1842 | * whose virtual address lies outside the file truncation point. | |
1843 | */ | |
1844 | restart: | |
1845 | list_for_each_entry(vma, head, shared.vm_set.list) { | |
1846 | /* Skip quickly over those we have already dealt with */ | |
1847 | if (vma->vm_truncate_count == details->truncate_count) | |
1848 | continue; | |
1849 | details->nonlinear_vma = vma; | |
1850 | if (unmap_mapping_range_vma(vma, vma->vm_start, | |
1851 | vma->vm_end, details) < 0) | |
1852 | goto restart; | |
1853 | } | |
1854 | } | |
1855 | ||
1856 | /** | |
72fd4a35 | 1857 | * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file. |
3d41088f | 1858 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
1859 | * @holebegin: byte in first page to unmap, relative to the start of |
1860 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
1861 | * boundary. Note that this is different from vmtruncate(), which | |
1862 | * must keep the partial page. In contrast, we must get rid of | |
1863 | * partial pages. | |
1864 | * @holelen: size of prospective hole in bytes. This will be rounded | |
1865 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
1866 | * end of the file. | |
1867 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
1868 | * but 0 when invalidating pagecache, don't throw away private data. | |
1869 | */ | |
1870 | void unmap_mapping_range(struct address_space *mapping, | |
1871 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
1872 | { | |
1873 | struct zap_details details; | |
1874 | pgoff_t hba = holebegin >> PAGE_SHIFT; | |
1875 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1876 | ||
1877 | /* Check for overflow. */ | |
1878 | if (sizeof(holelen) > sizeof(hlen)) { | |
1879 | long long holeend = | |
1880 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
1881 | if (holeend & ~(long long)ULONG_MAX) | |
1882 | hlen = ULONG_MAX - hba + 1; | |
1883 | } | |
1884 | ||
1885 | details.check_mapping = even_cows? NULL: mapping; | |
1886 | details.nonlinear_vma = NULL; | |
1887 | details.first_index = hba; | |
1888 | details.last_index = hba + hlen - 1; | |
1889 | if (details.last_index < details.first_index) | |
1890 | details.last_index = ULONG_MAX; | |
1891 | details.i_mmap_lock = &mapping->i_mmap_lock; | |
1892 | ||
1893 | spin_lock(&mapping->i_mmap_lock); | |
1894 | ||
d00806b1 | 1895 | /* Protect against endless unmapping loops */ |
1da177e4 | 1896 | mapping->truncate_count++; |
1da177e4 LT |
1897 | if (unlikely(is_restart_addr(mapping->truncate_count))) { |
1898 | if (mapping->truncate_count == 0) | |
1899 | reset_vma_truncate_counts(mapping); | |
1900 | mapping->truncate_count++; | |
1901 | } | |
1902 | details.truncate_count = mapping->truncate_count; | |
1903 | ||
1904 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) | |
1905 | unmap_mapping_range_tree(&mapping->i_mmap, &details); | |
1906 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) | |
1907 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); | |
1908 | spin_unlock(&mapping->i_mmap_lock); | |
1909 | } | |
1910 | EXPORT_SYMBOL(unmap_mapping_range); | |
1911 | ||
bfa5bf6d REB |
1912 | /** |
1913 | * vmtruncate - unmap mappings "freed" by truncate() syscall | |
1914 | * @inode: inode of the file used | |
1915 | * @offset: file offset to start truncating | |
1da177e4 LT |
1916 | * |
1917 | * NOTE! We have to be ready to update the memory sharing | |
1918 | * between the file and the memory map for a potential last | |
1919 | * incomplete page. Ugly, but necessary. | |
1920 | */ | |
1921 | int vmtruncate(struct inode * inode, loff_t offset) | |
1922 | { | |
61d5048f CH |
1923 | if (inode->i_size < offset) { |
1924 | unsigned long limit; | |
1925 | ||
1926 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
1927 | if (limit != RLIM_INFINITY && offset > limit) | |
1928 | goto out_sig; | |
1929 | if (offset > inode->i_sb->s_maxbytes) | |
1930 | goto out_big; | |
1931 | i_size_write(inode, offset); | |
1932 | } else { | |
1933 | struct address_space *mapping = inode->i_mapping; | |
1da177e4 | 1934 | |
61d5048f CH |
1935 | /* |
1936 | * truncation of in-use swapfiles is disallowed - it would | |
1937 | * cause subsequent swapout to scribble on the now-freed | |
1938 | * blocks. | |
1939 | */ | |
1940 | if (IS_SWAPFILE(inode)) | |
1941 | return -ETXTBSY; | |
1942 | i_size_write(inode, offset); | |
1943 | ||
1944 | /* | |
1945 | * unmap_mapping_range is called twice, first simply for | |
1946 | * efficiency so that truncate_inode_pages does fewer | |
1947 | * single-page unmaps. However after this first call, and | |
1948 | * before truncate_inode_pages finishes, it is possible for | |
1949 | * private pages to be COWed, which remain after | |
1950 | * truncate_inode_pages finishes, hence the second | |
1951 | * unmap_mapping_range call must be made for correctness. | |
1952 | */ | |
1953 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
1954 | truncate_inode_pages(mapping, offset); | |
1955 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
1956 | } | |
d00806b1 | 1957 | |
1da177e4 LT |
1958 | if (inode->i_op && inode->i_op->truncate) |
1959 | inode->i_op->truncate(inode); | |
1960 | return 0; | |
61d5048f | 1961 | |
1da177e4 LT |
1962 | out_sig: |
1963 | send_sig(SIGXFSZ, current, 0); | |
1964 | out_big: | |
1965 | return -EFBIG; | |
1da177e4 | 1966 | } |
1da177e4 LT |
1967 | EXPORT_SYMBOL(vmtruncate); |
1968 | ||
f6b3ec23 BP |
1969 | int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) |
1970 | { | |
1971 | struct address_space *mapping = inode->i_mapping; | |
1972 | ||
1973 | /* | |
1974 | * If the underlying filesystem is not going to provide | |
1975 | * a way to truncate a range of blocks (punch a hole) - | |
1976 | * we should return failure right now. | |
1977 | */ | |
1978 | if (!inode->i_op || !inode->i_op->truncate_range) | |
1979 | return -ENOSYS; | |
1980 | ||
1b1dcc1b | 1981 | mutex_lock(&inode->i_mutex); |
f6b3ec23 BP |
1982 | down_write(&inode->i_alloc_sem); |
1983 | unmap_mapping_range(mapping, offset, (end - offset), 1); | |
1984 | truncate_inode_pages_range(mapping, offset, end); | |
d00806b1 | 1985 | unmap_mapping_range(mapping, offset, (end - offset), 1); |
f6b3ec23 BP |
1986 | inode->i_op->truncate_range(inode, offset, end); |
1987 | up_write(&inode->i_alloc_sem); | |
1b1dcc1b | 1988 | mutex_unlock(&inode->i_mutex); |
f6b3ec23 BP |
1989 | |
1990 | return 0; | |
1991 | } | |
f6b3ec23 | 1992 | |
1da177e4 | 1993 | /* |
8f4e2101 HD |
1994 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
1995 | * but allow concurrent faults), and pte mapped but not yet locked. | |
1996 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 1997 | */ |
65500d23 HD |
1998 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1999 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2000 | int write_access, pte_t orig_pte) | |
1da177e4 | 2001 | { |
8f4e2101 | 2002 | spinlock_t *ptl; |
1da177e4 | 2003 | struct page *page; |
65500d23 | 2004 | swp_entry_t entry; |
1da177e4 | 2005 | pte_t pte; |
83c54070 | 2006 | int ret = 0; |
1da177e4 | 2007 | |
4c21e2f2 | 2008 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
8f4e2101 | 2009 | goto out; |
65500d23 HD |
2010 | |
2011 | entry = pte_to_swp_entry(orig_pte); | |
0697212a CL |
2012 | if (is_migration_entry(entry)) { |
2013 | migration_entry_wait(mm, pmd, address); | |
2014 | goto out; | |
2015 | } | |
0ff92245 | 2016 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2017 | page = lookup_swap_cache(entry); |
2018 | if (!page) { | |
098fe651 | 2019 | grab_swap_token(); /* Contend for token _before_ read-in */ |
02098fea HD |
2020 | page = swapin_readahead(entry, |
2021 | GFP_HIGHUSER_MOVABLE, vma, address); | |
1da177e4 LT |
2022 | if (!page) { |
2023 | /* | |
8f4e2101 HD |
2024 | * Back out if somebody else faulted in this pte |
2025 | * while we released the pte lock. | |
1da177e4 | 2026 | */ |
8f4e2101 | 2027 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2028 | if (likely(pte_same(*page_table, orig_pte))) |
2029 | ret = VM_FAULT_OOM; | |
0ff92245 | 2030 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2031 | goto unlock; |
1da177e4 LT |
2032 | } |
2033 | ||
2034 | /* Had to read the page from swap area: Major fault */ | |
2035 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2036 | count_vm_event(PGMAJFAULT); |
1da177e4 LT |
2037 | } |
2038 | ||
2039 | mark_page_accessed(page); | |
2040 | lock_page(page); | |
20a1022d | 2041 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2042 | |
2043 | /* | |
8f4e2101 | 2044 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 2045 | */ |
8f4e2101 | 2046 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
9e9bef07 | 2047 | if (unlikely(!pte_same(*page_table, orig_pte))) |
b8107480 | 2048 | goto out_nomap; |
b8107480 KK |
2049 | |
2050 | if (unlikely(!PageUptodate(page))) { | |
2051 | ret = VM_FAULT_SIGBUS; | |
2052 | goto out_nomap; | |
1da177e4 LT |
2053 | } |
2054 | ||
2055 | /* The page isn't present yet, go ahead with the fault. */ | |
1da177e4 | 2056 | |
4294621f | 2057 | inc_mm_counter(mm, anon_rss); |
1da177e4 LT |
2058 | pte = mk_pte(page, vma->vm_page_prot); |
2059 | if (write_access && can_share_swap_page(page)) { | |
2060 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); | |
2061 | write_access = 0; | |
2062 | } | |
1da177e4 LT |
2063 | |
2064 | flush_icache_page(vma, page); | |
2065 | set_pte_at(mm, address, page_table, pte); | |
2066 | page_add_anon_rmap(page, vma, address); | |
2067 | ||
c475a8ab HD |
2068 | swap_free(entry); |
2069 | if (vm_swap_full()) | |
2070 | remove_exclusive_swap_page(page); | |
2071 | unlock_page(page); | |
2072 | ||
1da177e4 | 2073 | if (write_access) { |
83c54070 | 2074 | /* XXX: We could OR the do_wp_page code with this one? */ |
1da177e4 | 2075 | if (do_wp_page(mm, vma, address, |
83c54070 | 2076 | page_table, pmd, ptl, pte) & VM_FAULT_OOM) |
1da177e4 LT |
2077 | ret = VM_FAULT_OOM; |
2078 | goto out; | |
2079 | } | |
2080 | ||
2081 | /* No need to invalidate - it was non-present before */ | |
2082 | update_mmu_cache(vma, address, pte); | |
65500d23 | 2083 | unlock: |
8f4e2101 | 2084 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2085 | out: |
2086 | return ret; | |
b8107480 | 2087 | out_nomap: |
8f4e2101 | 2088 | pte_unmap_unlock(page_table, ptl); |
b8107480 KK |
2089 | unlock_page(page); |
2090 | page_cache_release(page); | |
65500d23 | 2091 | return ret; |
1da177e4 LT |
2092 | } |
2093 | ||
2094 | /* | |
8f4e2101 HD |
2095 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2096 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2097 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2098 | */ |
65500d23 HD |
2099 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2100 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2101 | int write_access) | |
1da177e4 | 2102 | { |
8f4e2101 HD |
2103 | struct page *page; |
2104 | spinlock_t *ptl; | |
1da177e4 | 2105 | pte_t entry; |
1da177e4 | 2106 | |
557ed1fa NP |
2107 | /* Allocate our own private page. */ |
2108 | pte_unmap(page_table); | |
8f4e2101 | 2109 | |
557ed1fa NP |
2110 | if (unlikely(anon_vma_prepare(vma))) |
2111 | goto oom; | |
2112 | page = alloc_zeroed_user_highpage_movable(vma, address); | |
2113 | if (!page) | |
2114 | goto oom; | |
0ed361de | 2115 | __SetPageUptodate(page); |
8f4e2101 | 2116 | |
557ed1fa NP |
2117 | entry = mk_pte(page, vma->vm_page_prot); |
2118 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1da177e4 | 2119 | |
557ed1fa NP |
2120 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
2121 | if (!pte_none(*page_table)) | |
2122 | goto release; | |
2123 | inc_mm_counter(mm, anon_rss); | |
2124 | lru_cache_add_active(page); | |
2125 | page_add_new_anon_rmap(page, vma, address); | |
65500d23 | 2126 | set_pte_at(mm, address, page_table, entry); |
1da177e4 LT |
2127 | |
2128 | /* No need to invalidate - it was non-present before */ | |
65500d23 | 2129 | update_mmu_cache(vma, address, entry); |
65500d23 | 2130 | unlock: |
8f4e2101 | 2131 | pte_unmap_unlock(page_table, ptl); |
83c54070 | 2132 | return 0; |
8f4e2101 HD |
2133 | release: |
2134 | page_cache_release(page); | |
2135 | goto unlock; | |
65500d23 | 2136 | oom: |
1da177e4 LT |
2137 | return VM_FAULT_OOM; |
2138 | } | |
2139 | ||
2140 | /* | |
54cb8821 | 2141 | * __do_fault() tries to create a new page mapping. It aggressively |
1da177e4 | 2142 | * tries to share with existing pages, but makes a separate copy if |
54cb8821 NP |
2143 | * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid |
2144 | * the next page fault. | |
1da177e4 LT |
2145 | * |
2146 | * As this is called only for pages that do not currently exist, we | |
2147 | * do not need to flush old virtual caches or the TLB. | |
2148 | * | |
8f4e2101 | 2149 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
16abfa08 | 2150 | * but allow concurrent faults), and pte neither mapped nor locked. |
8f4e2101 | 2151 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
1da177e4 | 2152 | */ |
54cb8821 | 2153 | static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
16abfa08 | 2154 | unsigned long address, pmd_t *pmd, |
54cb8821 | 2155 | pgoff_t pgoff, unsigned int flags, pte_t orig_pte) |
1da177e4 | 2156 | { |
16abfa08 | 2157 | pte_t *page_table; |
8f4e2101 | 2158 | spinlock_t *ptl; |
d0217ac0 | 2159 | struct page *page; |
1da177e4 | 2160 | pte_t entry; |
1da177e4 | 2161 | int anon = 0; |
d08b3851 | 2162 | struct page *dirty_page = NULL; |
d0217ac0 NP |
2163 | struct vm_fault vmf; |
2164 | int ret; | |
a200ee18 | 2165 | int page_mkwrite = 0; |
54cb8821 | 2166 | |
d0217ac0 NP |
2167 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); |
2168 | vmf.pgoff = pgoff; | |
2169 | vmf.flags = flags; | |
2170 | vmf.page = NULL; | |
1da177e4 | 2171 | |
325f04db HD |
2172 | BUG_ON(vma->vm_flags & VM_PFNMAP); |
2173 | ||
54cb8821 | 2174 | if (likely(vma->vm_ops->fault)) { |
d0217ac0 | 2175 | ret = vma->vm_ops->fault(vma, &vmf); |
83c54070 NP |
2176 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) |
2177 | return ret; | |
54cb8821 NP |
2178 | } else { |
2179 | /* Legacy ->nopage path */ | |
83c54070 | 2180 | ret = 0; |
d0217ac0 | 2181 | vmf.page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret); |
54cb8821 | 2182 | /* no page was available -- either SIGBUS or OOM */ |
d0217ac0 | 2183 | if (unlikely(vmf.page == NOPAGE_SIGBUS)) |
54cb8821 | 2184 | return VM_FAULT_SIGBUS; |
d0217ac0 | 2185 | else if (unlikely(vmf.page == NOPAGE_OOM)) |
54cb8821 NP |
2186 | return VM_FAULT_OOM; |
2187 | } | |
1da177e4 | 2188 | |
d00806b1 | 2189 | /* |
d0217ac0 | 2190 | * For consistency in subsequent calls, make the faulted page always |
d00806b1 NP |
2191 | * locked. |
2192 | */ | |
83c54070 | 2193 | if (unlikely(!(ret & VM_FAULT_LOCKED))) |
d0217ac0 | 2194 | lock_page(vmf.page); |
54cb8821 | 2195 | else |
d0217ac0 | 2196 | VM_BUG_ON(!PageLocked(vmf.page)); |
d00806b1 | 2197 | |
1da177e4 LT |
2198 | /* |
2199 | * Should we do an early C-O-W break? | |
2200 | */ | |
d0217ac0 | 2201 | page = vmf.page; |
54cb8821 | 2202 | if (flags & FAULT_FLAG_WRITE) { |
9637a5ef | 2203 | if (!(vma->vm_flags & VM_SHARED)) { |
54cb8821 | 2204 | anon = 1; |
d00806b1 | 2205 | if (unlikely(anon_vma_prepare(vma))) { |
d0217ac0 | 2206 | ret = VM_FAULT_OOM; |
54cb8821 | 2207 | goto out; |
d00806b1 | 2208 | } |
83c54070 NP |
2209 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, |
2210 | vma, address); | |
d00806b1 | 2211 | if (!page) { |
d0217ac0 | 2212 | ret = VM_FAULT_OOM; |
54cb8821 | 2213 | goto out; |
d00806b1 | 2214 | } |
d0217ac0 | 2215 | copy_user_highpage(page, vmf.page, address, vma); |
0ed361de | 2216 | __SetPageUptodate(page); |
9637a5ef | 2217 | } else { |
54cb8821 NP |
2218 | /* |
2219 | * If the page will be shareable, see if the backing | |
9637a5ef | 2220 | * address space wants to know that the page is about |
54cb8821 NP |
2221 | * to become writable |
2222 | */ | |
69676147 MF |
2223 | if (vma->vm_ops->page_mkwrite) { |
2224 | unlock_page(page); | |
2225 | if (vma->vm_ops->page_mkwrite(vma, page) < 0) { | |
d0217ac0 NP |
2226 | ret = VM_FAULT_SIGBUS; |
2227 | anon = 1; /* no anon but release vmf.page */ | |
69676147 MF |
2228 | goto out_unlocked; |
2229 | } | |
2230 | lock_page(page); | |
d0217ac0 NP |
2231 | /* |
2232 | * XXX: this is not quite right (racy vs | |
2233 | * invalidate) to unlock and relock the page | |
2234 | * like this, however a better fix requires | |
2235 | * reworking page_mkwrite locking API, which | |
2236 | * is better done later. | |
2237 | */ | |
2238 | if (!page->mapping) { | |
83c54070 | 2239 | ret = 0; |
d0217ac0 NP |
2240 | anon = 1; /* no anon but release vmf.page */ |
2241 | goto out; | |
2242 | } | |
a200ee18 | 2243 | page_mkwrite = 1; |
9637a5ef DH |
2244 | } |
2245 | } | |
54cb8821 | 2246 | |
1da177e4 LT |
2247 | } |
2248 | ||
8f4e2101 | 2249 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2250 | |
2251 | /* | |
2252 | * This silly early PAGE_DIRTY setting removes a race | |
2253 | * due to the bad i386 page protection. But it's valid | |
2254 | * for other architectures too. | |
2255 | * | |
2256 | * Note that if write_access is true, we either now have | |
2257 | * an exclusive copy of the page, or this is a shared mapping, | |
2258 | * so we can make it writable and dirty to avoid having to | |
2259 | * handle that later. | |
2260 | */ | |
2261 | /* Only go through if we didn't race with anybody else... */ | |
54cb8821 | 2262 | if (likely(pte_same(*page_table, orig_pte))) { |
d00806b1 NP |
2263 | flush_icache_page(vma, page); |
2264 | entry = mk_pte(page, vma->vm_page_prot); | |
54cb8821 | 2265 | if (flags & FAULT_FLAG_WRITE) |
1da177e4 LT |
2266 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
2267 | set_pte_at(mm, address, page_table, entry); | |
2268 | if (anon) { | |
d00806b1 NP |
2269 | inc_mm_counter(mm, anon_rss); |
2270 | lru_cache_add_active(page); | |
2271 | page_add_new_anon_rmap(page, vma, address); | |
f57e88a8 | 2272 | } else { |
4294621f | 2273 | inc_mm_counter(mm, file_rss); |
d00806b1 | 2274 | page_add_file_rmap(page); |
54cb8821 | 2275 | if (flags & FAULT_FLAG_WRITE) { |
d00806b1 | 2276 | dirty_page = page; |
d08b3851 PZ |
2277 | get_page(dirty_page); |
2278 | } | |
4294621f | 2279 | } |
d00806b1 NP |
2280 | |
2281 | /* no need to invalidate: a not-present page won't be cached */ | |
2282 | update_mmu_cache(vma, address, entry); | |
1da177e4 | 2283 | } else { |
d00806b1 NP |
2284 | if (anon) |
2285 | page_cache_release(page); | |
2286 | else | |
54cb8821 | 2287 | anon = 1; /* no anon but release faulted_page */ |
1da177e4 LT |
2288 | } |
2289 | ||
8f4e2101 | 2290 | pte_unmap_unlock(page_table, ptl); |
d00806b1 NP |
2291 | |
2292 | out: | |
d0217ac0 | 2293 | unlock_page(vmf.page); |
69676147 | 2294 | out_unlocked: |
d00806b1 | 2295 | if (anon) |
d0217ac0 | 2296 | page_cache_release(vmf.page); |
d00806b1 | 2297 | else if (dirty_page) { |
8f7b3d15 AS |
2298 | if (vma->vm_file) |
2299 | file_update_time(vma->vm_file); | |
2300 | ||
a200ee18 | 2301 | set_page_dirty_balance(dirty_page, page_mkwrite); |
d08b3851 PZ |
2302 | put_page(dirty_page); |
2303 | } | |
d00806b1 | 2304 | |
83c54070 | 2305 | return ret; |
54cb8821 | 2306 | } |
d00806b1 | 2307 | |
54cb8821 NP |
2308 | static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
2309 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2310 | int write_access, pte_t orig_pte) | |
2311 | { | |
2312 | pgoff_t pgoff = (((address & PAGE_MASK) | |
0da7e01f | 2313 | - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
54cb8821 NP |
2314 | unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0); |
2315 | ||
16abfa08 HD |
2316 | pte_unmap(page_table); |
2317 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); | |
54cb8821 NP |
2318 | } |
2319 | ||
1da177e4 | 2320 | |
f4b81804 JS |
2321 | /* |
2322 | * do_no_pfn() tries to create a new page mapping for a page without | |
2323 | * a struct_page backing it | |
2324 | * | |
2325 | * As this is called only for pages that do not currently exist, we | |
2326 | * do not need to flush old virtual caches or the TLB. | |
2327 | * | |
2328 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
2329 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2330 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
2331 | * | |
2332 | * It is expected that the ->nopfn handler always returns the same pfn | |
2333 | * for a given virtual mapping. | |
2334 | * | |
2335 | * Mark this `noinline' to prevent it from bloating the main pagefault code. | |
2336 | */ | |
2337 | static noinline int do_no_pfn(struct mm_struct *mm, struct vm_area_struct *vma, | |
2338 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2339 | int write_access) | |
2340 | { | |
2341 | spinlock_t *ptl; | |
2342 | pte_t entry; | |
2343 | unsigned long pfn; | |
f4b81804 JS |
2344 | |
2345 | pte_unmap(page_table); | |
2346 | BUG_ON(!(vma->vm_flags & VM_PFNMAP)); | |
2347 | BUG_ON(is_cow_mapping(vma->vm_flags)); | |
2348 | ||
2349 | pfn = vma->vm_ops->nopfn(vma, address & PAGE_MASK); | |
22cd25ed | 2350 | if (unlikely(pfn == NOPFN_OOM)) |
f4b81804 | 2351 | return VM_FAULT_OOM; |
22cd25ed | 2352 | else if (unlikely(pfn == NOPFN_SIGBUS)) |
f4b81804 | 2353 | return VM_FAULT_SIGBUS; |
22cd25ed | 2354 | else if (unlikely(pfn == NOPFN_REFAULT)) |
83c54070 | 2355 | return 0; |
f4b81804 JS |
2356 | |
2357 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2358 | ||
2359 | /* Only go through if we didn't race with anybody else... */ | |
2360 | if (pte_none(*page_table)) { | |
2361 | entry = pfn_pte(pfn, vma->vm_page_prot); | |
2362 | if (write_access) | |
2363 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
2364 | set_pte_at(mm, address, page_table, entry); | |
2365 | } | |
2366 | pte_unmap_unlock(page_table, ptl); | |
83c54070 | 2367 | return 0; |
f4b81804 JS |
2368 | } |
2369 | ||
1da177e4 LT |
2370 | /* |
2371 | * Fault of a previously existing named mapping. Repopulate the pte | |
2372 | * from the encoded file_pte if possible. This enables swappable | |
2373 | * nonlinear vmas. | |
8f4e2101 HD |
2374 | * |
2375 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
2376 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2377 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2378 | */ |
d0217ac0 | 2379 | static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
65500d23 HD |
2380 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
2381 | int write_access, pte_t orig_pte) | |
1da177e4 | 2382 | { |
d0217ac0 NP |
2383 | unsigned int flags = FAULT_FLAG_NONLINEAR | |
2384 | (write_access ? FAULT_FLAG_WRITE : 0); | |
65500d23 | 2385 | pgoff_t pgoff; |
1da177e4 | 2386 | |
4c21e2f2 | 2387 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
83c54070 | 2388 | return 0; |
1da177e4 | 2389 | |
d0217ac0 NP |
2390 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR) || |
2391 | !(vma->vm_flags & VM_CAN_NONLINEAR))) { | |
65500d23 HD |
2392 | /* |
2393 | * Page table corrupted: show pte and kill process. | |
2394 | */ | |
b5810039 | 2395 | print_bad_pte(vma, orig_pte, address); |
65500d23 HD |
2396 | return VM_FAULT_OOM; |
2397 | } | |
65500d23 HD |
2398 | |
2399 | pgoff = pte_to_pgoff(orig_pte); | |
16abfa08 | 2400 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); |
1da177e4 LT |
2401 | } |
2402 | ||
2403 | /* | |
2404 | * These routines also need to handle stuff like marking pages dirty | |
2405 | * and/or accessed for architectures that don't do it in hardware (most | |
2406 | * RISC architectures). The early dirtying is also good on the i386. | |
2407 | * | |
2408 | * There is also a hook called "update_mmu_cache()" that architectures | |
2409 | * with external mmu caches can use to update those (ie the Sparc or | |
2410 | * PowerPC hashed page tables that act as extended TLBs). | |
2411 | * | |
c74df32c HD |
2412 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2413 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2414 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 LT |
2415 | */ |
2416 | static inline int handle_pte_fault(struct mm_struct *mm, | |
65500d23 HD |
2417 | struct vm_area_struct *vma, unsigned long address, |
2418 | pte_t *pte, pmd_t *pmd, int write_access) | |
1da177e4 LT |
2419 | { |
2420 | pte_t entry; | |
8f4e2101 | 2421 | spinlock_t *ptl; |
1da177e4 | 2422 | |
8dab5241 | 2423 | entry = *pte; |
1da177e4 | 2424 | if (!pte_present(entry)) { |
65500d23 | 2425 | if (pte_none(entry)) { |
f4b81804 | 2426 | if (vma->vm_ops) { |
54cb8821 NP |
2427 | if (vma->vm_ops->fault || vma->vm_ops->nopage) |
2428 | return do_linear_fault(mm, vma, address, | |
2429 | pte, pmd, write_access, entry); | |
f4b81804 JS |
2430 | if (unlikely(vma->vm_ops->nopfn)) |
2431 | return do_no_pfn(mm, vma, address, pte, | |
2432 | pmd, write_access); | |
2433 | } | |
2434 | return do_anonymous_page(mm, vma, address, | |
2435 | pte, pmd, write_access); | |
65500d23 | 2436 | } |
1da177e4 | 2437 | if (pte_file(entry)) |
d0217ac0 | 2438 | return do_nonlinear_fault(mm, vma, address, |
65500d23 HD |
2439 | pte, pmd, write_access, entry); |
2440 | return do_swap_page(mm, vma, address, | |
2441 | pte, pmd, write_access, entry); | |
1da177e4 LT |
2442 | } |
2443 | ||
4c21e2f2 | 2444 | ptl = pte_lockptr(mm, pmd); |
8f4e2101 HD |
2445 | spin_lock(ptl); |
2446 | if (unlikely(!pte_same(*pte, entry))) | |
2447 | goto unlock; | |
1da177e4 LT |
2448 | if (write_access) { |
2449 | if (!pte_write(entry)) | |
8f4e2101 HD |
2450 | return do_wp_page(mm, vma, address, |
2451 | pte, pmd, ptl, entry); | |
1da177e4 LT |
2452 | entry = pte_mkdirty(entry); |
2453 | } | |
2454 | entry = pte_mkyoung(entry); | |
8dab5241 | 2455 | if (ptep_set_access_flags(vma, address, pte, entry, write_access)) { |
1a44e149 | 2456 | update_mmu_cache(vma, address, entry); |
1a44e149 AA |
2457 | } else { |
2458 | /* | |
2459 | * This is needed only for protection faults but the arch code | |
2460 | * is not yet telling us if this is a protection fault or not. | |
2461 | * This still avoids useless tlb flushes for .text page faults | |
2462 | * with threads. | |
2463 | */ | |
2464 | if (write_access) | |
2465 | flush_tlb_page(vma, address); | |
2466 | } | |
8f4e2101 HD |
2467 | unlock: |
2468 | pte_unmap_unlock(pte, ptl); | |
83c54070 | 2469 | return 0; |
1da177e4 LT |
2470 | } |
2471 | ||
2472 | /* | |
2473 | * By the time we get here, we already hold the mm semaphore | |
2474 | */ | |
83c54070 | 2475 | int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
1da177e4 LT |
2476 | unsigned long address, int write_access) |
2477 | { | |
2478 | pgd_t *pgd; | |
2479 | pud_t *pud; | |
2480 | pmd_t *pmd; | |
2481 | pte_t *pte; | |
2482 | ||
2483 | __set_current_state(TASK_RUNNING); | |
2484 | ||
f8891e5e | 2485 | count_vm_event(PGFAULT); |
1da177e4 | 2486 | |
ac9b9c66 HD |
2487 | if (unlikely(is_vm_hugetlb_page(vma))) |
2488 | return hugetlb_fault(mm, vma, address, write_access); | |
1da177e4 | 2489 | |
1da177e4 | 2490 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
2491 | pud = pud_alloc(mm, pgd, address); |
2492 | if (!pud) | |
c74df32c | 2493 | return VM_FAULT_OOM; |
1da177e4 LT |
2494 | pmd = pmd_alloc(mm, pud, address); |
2495 | if (!pmd) | |
c74df32c | 2496 | return VM_FAULT_OOM; |
1da177e4 LT |
2497 | pte = pte_alloc_map(mm, pmd, address); |
2498 | if (!pte) | |
c74df32c | 2499 | return VM_FAULT_OOM; |
1da177e4 | 2500 | |
c74df32c | 2501 | return handle_pte_fault(mm, vma, address, pte, pmd, write_access); |
1da177e4 LT |
2502 | } |
2503 | ||
2504 | #ifndef __PAGETABLE_PUD_FOLDED | |
2505 | /* | |
2506 | * Allocate page upper directory. | |
872fec16 | 2507 | * We've already handled the fast-path in-line. |
1da177e4 | 2508 | */ |
1bb3630e | 2509 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 2510 | { |
c74df32c HD |
2511 | pud_t *new = pud_alloc_one(mm, address); |
2512 | if (!new) | |
1bb3630e | 2513 | return -ENOMEM; |
1da177e4 | 2514 | |
872fec16 | 2515 | spin_lock(&mm->page_table_lock); |
1bb3630e | 2516 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 2517 | pud_free(mm, new); |
1bb3630e HD |
2518 | else |
2519 | pgd_populate(mm, pgd, new); | |
c74df32c | 2520 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 2521 | return 0; |
1da177e4 LT |
2522 | } |
2523 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
2524 | ||
2525 | #ifndef __PAGETABLE_PMD_FOLDED | |
2526 | /* | |
2527 | * Allocate page middle directory. | |
872fec16 | 2528 | * We've already handled the fast-path in-line. |
1da177e4 | 2529 | */ |
1bb3630e | 2530 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 2531 | { |
c74df32c HD |
2532 | pmd_t *new = pmd_alloc_one(mm, address); |
2533 | if (!new) | |
1bb3630e | 2534 | return -ENOMEM; |
1da177e4 | 2535 | |
872fec16 | 2536 | spin_lock(&mm->page_table_lock); |
1da177e4 | 2537 | #ifndef __ARCH_HAS_4LEVEL_HACK |
1bb3630e | 2538 | if (pud_present(*pud)) /* Another has populated it */ |
5e541973 | 2539 | pmd_free(mm, new); |
1bb3630e HD |
2540 | else |
2541 | pud_populate(mm, pud, new); | |
1da177e4 | 2542 | #else |
1bb3630e | 2543 | if (pgd_present(*pud)) /* Another has populated it */ |
5e541973 | 2544 | pmd_free(mm, new); |
1bb3630e HD |
2545 | else |
2546 | pgd_populate(mm, pud, new); | |
1da177e4 | 2547 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 2548 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 2549 | return 0; |
e0f39591 | 2550 | } |
1da177e4 LT |
2551 | #endif /* __PAGETABLE_PMD_FOLDED */ |
2552 | ||
2553 | int make_pages_present(unsigned long addr, unsigned long end) | |
2554 | { | |
2555 | int ret, len, write; | |
2556 | struct vm_area_struct * vma; | |
2557 | ||
2558 | vma = find_vma(current->mm, addr); | |
2559 | if (!vma) | |
2560 | return -1; | |
2561 | write = (vma->vm_flags & VM_WRITE) != 0; | |
5bcb28b1 ES |
2562 | BUG_ON(addr >= end); |
2563 | BUG_ON(end > vma->vm_end); | |
68e116a3 | 2564 | len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; |
1da177e4 LT |
2565 | ret = get_user_pages(current, current->mm, addr, |
2566 | len, write, 0, NULL, NULL); | |
2567 | if (ret < 0) | |
2568 | return ret; | |
2569 | return ret == len ? 0 : -1; | |
2570 | } | |
2571 | ||
1da177e4 LT |
2572 | #if !defined(__HAVE_ARCH_GATE_AREA) |
2573 | ||
2574 | #if defined(AT_SYSINFO_EHDR) | |
5ce7852c | 2575 | static struct vm_area_struct gate_vma; |
1da177e4 LT |
2576 | |
2577 | static int __init gate_vma_init(void) | |
2578 | { | |
2579 | gate_vma.vm_mm = NULL; | |
2580 | gate_vma.vm_start = FIXADDR_USER_START; | |
2581 | gate_vma.vm_end = FIXADDR_USER_END; | |
b6558c4a RM |
2582 | gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; |
2583 | gate_vma.vm_page_prot = __P101; | |
f47aef55 RM |
2584 | /* |
2585 | * Make sure the vDSO gets into every core dump. | |
2586 | * Dumping its contents makes post-mortem fully interpretable later | |
2587 | * without matching up the same kernel and hardware config to see | |
2588 | * what PC values meant. | |
2589 | */ | |
2590 | gate_vma.vm_flags |= VM_ALWAYSDUMP; | |
1da177e4 LT |
2591 | return 0; |
2592 | } | |
2593 | __initcall(gate_vma_init); | |
2594 | #endif | |
2595 | ||
2596 | struct vm_area_struct *get_gate_vma(struct task_struct *tsk) | |
2597 | { | |
2598 | #ifdef AT_SYSINFO_EHDR | |
2599 | return &gate_vma; | |
2600 | #else | |
2601 | return NULL; | |
2602 | #endif | |
2603 | } | |
2604 | ||
2605 | int in_gate_area_no_task(unsigned long addr) | |
2606 | { | |
2607 | #ifdef AT_SYSINFO_EHDR | |
2608 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) | |
2609 | return 1; | |
2610 | #endif | |
2611 | return 0; | |
2612 | } | |
2613 | ||
2614 | #endif /* __HAVE_ARCH_GATE_AREA */ | |
0ec76a11 DH |
2615 | |
2616 | /* | |
2617 | * Access another process' address space. | |
2618 | * Source/target buffer must be kernel space, | |
2619 | * Do not walk the page table directly, use get_user_pages | |
2620 | */ | |
2621 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
2622 | { | |
2623 | struct mm_struct *mm; | |
2624 | struct vm_area_struct *vma; | |
2625 | struct page *page; | |
2626 | void *old_buf = buf; | |
2627 | ||
2628 | mm = get_task_mm(tsk); | |
2629 | if (!mm) | |
2630 | return 0; | |
2631 | ||
2632 | down_read(&mm->mmap_sem); | |
183ff22b | 2633 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
2634 | while (len) { |
2635 | int bytes, ret, offset; | |
2636 | void *maddr; | |
2637 | ||
2638 | ret = get_user_pages(tsk, mm, addr, 1, | |
2639 | write, 1, &page, &vma); | |
2640 | if (ret <= 0) | |
2641 | break; | |
2642 | ||
2643 | bytes = len; | |
2644 | offset = addr & (PAGE_SIZE-1); | |
2645 | if (bytes > PAGE_SIZE-offset) | |
2646 | bytes = PAGE_SIZE-offset; | |
2647 | ||
2648 | maddr = kmap(page); | |
2649 | if (write) { | |
2650 | copy_to_user_page(vma, page, addr, | |
2651 | maddr + offset, buf, bytes); | |
2652 | set_page_dirty_lock(page); | |
2653 | } else { | |
2654 | copy_from_user_page(vma, page, addr, | |
2655 | buf, maddr + offset, bytes); | |
2656 | } | |
2657 | kunmap(page); | |
2658 | page_cache_release(page); | |
2659 | len -= bytes; | |
2660 | buf += bytes; | |
2661 | addr += bytes; | |
2662 | } | |
2663 | up_read(&mm->mmap_sem); | |
2664 | mmput(mm); | |
2665 | ||
2666 | return buf - old_buf; | |
2667 | } | |
03252919 AK |
2668 | |
2669 | /* | |
2670 | * Print the name of a VMA. | |
2671 | */ | |
2672 | void print_vma_addr(char *prefix, unsigned long ip) | |
2673 | { | |
2674 | struct mm_struct *mm = current->mm; | |
2675 | struct vm_area_struct *vma; | |
2676 | ||
2677 | down_read(&mm->mmap_sem); | |
2678 | vma = find_vma(mm, ip); | |
2679 | if (vma && vma->vm_file) { | |
2680 | struct file *f = vma->vm_file; | |
2681 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
2682 | if (buf) { | |
2683 | char *p, *s; | |
2684 | ||
2685 | p = d_path(f->f_dentry, f->f_vfsmnt, buf, PAGE_SIZE); | |
2686 | if (IS_ERR(p)) | |
2687 | p = "?"; | |
2688 | s = strrchr(p, '/'); | |
2689 | if (s) | |
2690 | p = s+1; | |
2691 | printk("%s%s[%lx+%lx]", prefix, p, | |
2692 | vma->vm_start, | |
2693 | vma->vm_end - vma->vm_start); | |
2694 | free_page((unsigned long)buf); | |
2695 | } | |
2696 | } | |
2697 | up_read(¤t->mm->mmap_sem); | |
2698 | } |