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Commit | Line | Data |
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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> | |
9a840895 | 48 | #include <linux/ksm.h> |
1da177e4 | 49 | #include <linux/rmap.h> |
b95f1b31 | 50 | #include <linux/export.h> |
0ff92245 | 51 | #include <linux/delayacct.h> |
1da177e4 | 52 | #include <linux/init.h> |
edc79b2a | 53 | #include <linux/writeback.h> |
8a9f3ccd | 54 | #include <linux/memcontrol.h> |
cddb8a5c | 55 | #include <linux/mmu_notifier.h> |
3dc14741 HD |
56 | #include <linux/kallsyms.h> |
57 | #include <linux/swapops.h> | |
58 | #include <linux/elf.h> | |
5a0e3ad6 | 59 | #include <linux/gfp.h> |
4daae3b4 | 60 | #include <linux/migrate.h> |
2fbc57c5 | 61 | #include <linux/string.h> |
1da177e4 | 62 | |
6952b61d | 63 | #include <asm/io.h> |
1da177e4 LT |
64 | #include <asm/pgalloc.h> |
65 | #include <asm/uaccess.h> | |
66 | #include <asm/tlb.h> | |
67 | #include <asm/tlbflush.h> | |
68 | #include <asm/pgtable.h> | |
69 | ||
42b77728 JB |
70 | #include "internal.h" |
71 | ||
d41dee36 | 72 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
73 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
74 | unsigned long max_mapnr; | |
75 | struct page *mem_map; | |
76 | ||
77 | EXPORT_SYMBOL(max_mapnr); | |
78 | EXPORT_SYMBOL(mem_map); | |
79 | #endif | |
80 | ||
81 | unsigned long num_physpages; | |
82 | /* | |
83 | * A number of key systems in x86 including ioremap() rely on the assumption | |
84 | * that high_memory defines the upper bound on direct map memory, then end | |
85 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and | |
86 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL | |
87 | * and ZONE_HIGHMEM. | |
88 | */ | |
89 | void * high_memory; | |
1da177e4 LT |
90 | |
91 | EXPORT_SYMBOL(num_physpages); | |
92 | EXPORT_SYMBOL(high_memory); | |
1da177e4 | 93 | |
32a93233 IM |
94 | /* |
95 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
96 | * | |
97 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
98 | * as ancient (libc5 based) binaries can segfault. ) | |
99 | */ | |
100 | int randomize_va_space __read_mostly = | |
101 | #ifdef CONFIG_COMPAT_BRK | |
102 | 1; | |
103 | #else | |
104 | 2; | |
105 | #endif | |
a62eaf15 AK |
106 | |
107 | static int __init disable_randmaps(char *s) | |
108 | { | |
109 | randomize_va_space = 0; | |
9b41046c | 110 | return 1; |
a62eaf15 AK |
111 | } |
112 | __setup("norandmaps", disable_randmaps); | |
113 | ||
62eede62 | 114 | unsigned long zero_pfn __read_mostly; |
03f6462a | 115 | unsigned long highest_memmap_pfn __read_mostly; |
a13ea5b7 HD |
116 | |
117 | /* | |
118 | * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() | |
119 | */ | |
120 | static int __init init_zero_pfn(void) | |
121 | { | |
122 | zero_pfn = page_to_pfn(ZERO_PAGE(0)); | |
123 | return 0; | |
124 | } | |
125 | core_initcall(init_zero_pfn); | |
a62eaf15 | 126 | |
d559db08 | 127 | |
34e55232 KH |
128 | #if defined(SPLIT_RSS_COUNTING) |
129 | ||
ea48cf78 | 130 | void sync_mm_rss(struct mm_struct *mm) |
34e55232 KH |
131 | { |
132 | int i; | |
133 | ||
134 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
05af2e10 DR |
135 | if (current->rss_stat.count[i]) { |
136 | add_mm_counter(mm, i, current->rss_stat.count[i]); | |
137 | current->rss_stat.count[i] = 0; | |
34e55232 KH |
138 | } |
139 | } | |
05af2e10 | 140 | current->rss_stat.events = 0; |
34e55232 KH |
141 | } |
142 | ||
143 | static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) | |
144 | { | |
145 | struct task_struct *task = current; | |
146 | ||
147 | if (likely(task->mm == mm)) | |
148 | task->rss_stat.count[member] += val; | |
149 | else | |
150 | add_mm_counter(mm, member, val); | |
151 | } | |
152 | #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) | |
153 | #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) | |
154 | ||
155 | /* sync counter once per 64 page faults */ | |
156 | #define TASK_RSS_EVENTS_THRESH (64) | |
157 | static void check_sync_rss_stat(struct task_struct *task) | |
158 | { | |
159 | if (unlikely(task != current)) | |
160 | return; | |
161 | if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) | |
ea48cf78 | 162 | sync_mm_rss(task->mm); |
34e55232 | 163 | } |
9547d01b | 164 | #else /* SPLIT_RSS_COUNTING */ |
34e55232 KH |
165 | |
166 | #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) | |
167 | #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) | |
168 | ||
169 | static void check_sync_rss_stat(struct task_struct *task) | |
170 | { | |
171 | } | |
172 | ||
9547d01b PZ |
173 | #endif /* SPLIT_RSS_COUNTING */ |
174 | ||
175 | #ifdef HAVE_GENERIC_MMU_GATHER | |
176 | ||
177 | static int tlb_next_batch(struct mmu_gather *tlb) | |
178 | { | |
179 | struct mmu_gather_batch *batch; | |
180 | ||
181 | batch = tlb->active; | |
182 | if (batch->next) { | |
183 | tlb->active = batch->next; | |
184 | return 1; | |
185 | } | |
186 | ||
53a59fc6 MH |
187 | if (tlb->batch_count == MAX_GATHER_BATCH_COUNT) |
188 | return 0; | |
189 | ||
9547d01b PZ |
190 | batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); |
191 | if (!batch) | |
192 | return 0; | |
193 | ||
53a59fc6 | 194 | tlb->batch_count++; |
9547d01b PZ |
195 | batch->next = NULL; |
196 | batch->nr = 0; | |
197 | batch->max = MAX_GATHER_BATCH; | |
198 | ||
199 | tlb->active->next = batch; | |
200 | tlb->active = batch; | |
201 | ||
202 | return 1; | |
203 | } | |
204 | ||
205 | /* tlb_gather_mmu | |
206 | * Called to initialize an (on-stack) mmu_gather structure for page-table | |
207 | * tear-down from @mm. The @fullmm argument is used when @mm is without | |
208 | * users and we're going to destroy the full address space (exit/execve). | |
209 | */ | |
210 | void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm) | |
211 | { | |
212 | tlb->mm = mm; | |
213 | ||
214 | tlb->fullmm = fullmm; | |
597e1c35 AS |
215 | tlb->start = -1UL; |
216 | tlb->end = 0; | |
9547d01b PZ |
217 | tlb->need_flush = 0; |
218 | tlb->fast_mode = (num_possible_cpus() == 1); | |
219 | tlb->local.next = NULL; | |
220 | tlb->local.nr = 0; | |
221 | tlb->local.max = ARRAY_SIZE(tlb->__pages); | |
222 | tlb->active = &tlb->local; | |
53a59fc6 | 223 | tlb->batch_count = 0; |
9547d01b PZ |
224 | |
225 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE | |
226 | tlb->batch = NULL; | |
227 | #endif | |
228 | } | |
229 | ||
230 | void tlb_flush_mmu(struct mmu_gather *tlb) | |
231 | { | |
232 | struct mmu_gather_batch *batch; | |
233 | ||
234 | if (!tlb->need_flush) | |
235 | return; | |
236 | tlb->need_flush = 0; | |
237 | tlb_flush(tlb); | |
238 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE | |
239 | tlb_table_flush(tlb); | |
34e55232 KH |
240 | #endif |
241 | ||
9547d01b PZ |
242 | if (tlb_fast_mode(tlb)) |
243 | return; | |
244 | ||
245 | for (batch = &tlb->local; batch; batch = batch->next) { | |
246 | free_pages_and_swap_cache(batch->pages, batch->nr); | |
247 | batch->nr = 0; | |
248 | } | |
249 | tlb->active = &tlb->local; | |
250 | } | |
251 | ||
252 | /* tlb_finish_mmu | |
253 | * Called at the end of the shootdown operation to free up any resources | |
254 | * that were required. | |
255 | */ | |
256 | void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) | |
257 | { | |
258 | struct mmu_gather_batch *batch, *next; | |
259 | ||
597e1c35 AS |
260 | tlb->start = start; |
261 | tlb->end = end; | |
9547d01b PZ |
262 | tlb_flush_mmu(tlb); |
263 | ||
264 | /* keep the page table cache within bounds */ | |
265 | check_pgt_cache(); | |
266 | ||
267 | for (batch = tlb->local.next; batch; batch = next) { | |
268 | next = batch->next; | |
269 | free_pages((unsigned long)batch, 0); | |
270 | } | |
271 | tlb->local.next = NULL; | |
272 | } | |
273 | ||
274 | /* __tlb_remove_page | |
275 | * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while | |
276 | * handling the additional races in SMP caused by other CPUs caching valid | |
277 | * mappings in their TLBs. Returns the number of free page slots left. | |
278 | * When out of page slots we must call tlb_flush_mmu(). | |
279 | */ | |
280 | int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) | |
281 | { | |
282 | struct mmu_gather_batch *batch; | |
283 | ||
f21760b1 | 284 | VM_BUG_ON(!tlb->need_flush); |
9547d01b PZ |
285 | |
286 | if (tlb_fast_mode(tlb)) { | |
287 | free_page_and_swap_cache(page); | |
288 | return 1; /* avoid calling tlb_flush_mmu() */ | |
289 | } | |
290 | ||
291 | batch = tlb->active; | |
292 | batch->pages[batch->nr++] = page; | |
293 | if (batch->nr == batch->max) { | |
294 | if (!tlb_next_batch(tlb)) | |
295 | return 0; | |
0b43c3aa | 296 | batch = tlb->active; |
9547d01b PZ |
297 | } |
298 | VM_BUG_ON(batch->nr > batch->max); | |
299 | ||
300 | return batch->max - batch->nr; | |
301 | } | |
302 | ||
303 | #endif /* HAVE_GENERIC_MMU_GATHER */ | |
304 | ||
26723911 PZ |
305 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE |
306 | ||
307 | /* | |
308 | * See the comment near struct mmu_table_batch. | |
309 | */ | |
310 | ||
311 | static void tlb_remove_table_smp_sync(void *arg) | |
312 | { | |
313 | /* Simply deliver the interrupt */ | |
314 | } | |
315 | ||
316 | static void tlb_remove_table_one(void *table) | |
317 | { | |
318 | /* | |
319 | * This isn't an RCU grace period and hence the page-tables cannot be | |
320 | * assumed to be actually RCU-freed. | |
321 | * | |
322 | * It is however sufficient for software page-table walkers that rely on | |
323 | * IRQ disabling. See the comment near struct mmu_table_batch. | |
324 | */ | |
325 | smp_call_function(tlb_remove_table_smp_sync, NULL, 1); | |
326 | __tlb_remove_table(table); | |
327 | } | |
328 | ||
329 | static void tlb_remove_table_rcu(struct rcu_head *head) | |
330 | { | |
331 | struct mmu_table_batch *batch; | |
332 | int i; | |
333 | ||
334 | batch = container_of(head, struct mmu_table_batch, rcu); | |
335 | ||
336 | for (i = 0; i < batch->nr; i++) | |
337 | __tlb_remove_table(batch->tables[i]); | |
338 | ||
339 | free_page((unsigned long)batch); | |
340 | } | |
341 | ||
342 | void tlb_table_flush(struct mmu_gather *tlb) | |
343 | { | |
344 | struct mmu_table_batch **batch = &tlb->batch; | |
345 | ||
346 | if (*batch) { | |
347 | call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); | |
348 | *batch = NULL; | |
349 | } | |
350 | } | |
351 | ||
352 | void tlb_remove_table(struct mmu_gather *tlb, void *table) | |
353 | { | |
354 | struct mmu_table_batch **batch = &tlb->batch; | |
355 | ||
356 | tlb->need_flush = 1; | |
357 | ||
358 | /* | |
359 | * When there's less then two users of this mm there cannot be a | |
360 | * concurrent page-table walk. | |
361 | */ | |
362 | if (atomic_read(&tlb->mm->mm_users) < 2) { | |
363 | __tlb_remove_table(table); | |
364 | return; | |
365 | } | |
366 | ||
367 | if (*batch == NULL) { | |
368 | *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); | |
369 | if (*batch == NULL) { | |
370 | tlb_remove_table_one(table); | |
371 | return; | |
372 | } | |
373 | (*batch)->nr = 0; | |
374 | } | |
375 | (*batch)->tables[(*batch)->nr++] = table; | |
376 | if ((*batch)->nr == MAX_TABLE_BATCH) | |
377 | tlb_table_flush(tlb); | |
378 | } | |
379 | ||
9547d01b | 380 | #endif /* CONFIG_HAVE_RCU_TABLE_FREE */ |
26723911 | 381 | |
1da177e4 LT |
382 | /* |
383 | * If a p?d_bad entry is found while walking page tables, report | |
384 | * the error, before resetting entry to p?d_none. Usually (but | |
385 | * very seldom) called out from the p?d_none_or_clear_bad macros. | |
386 | */ | |
387 | ||
388 | void pgd_clear_bad(pgd_t *pgd) | |
389 | { | |
390 | pgd_ERROR(*pgd); | |
391 | pgd_clear(pgd); | |
392 | } | |
393 | ||
394 | void pud_clear_bad(pud_t *pud) | |
395 | { | |
396 | pud_ERROR(*pud); | |
397 | pud_clear(pud); | |
398 | } | |
399 | ||
400 | void pmd_clear_bad(pmd_t *pmd) | |
401 | { | |
402 | pmd_ERROR(*pmd); | |
403 | pmd_clear(pmd); | |
404 | } | |
405 | ||
406 | /* | |
407 | * Note: this doesn't free the actual pages themselves. That | |
408 | * has been handled earlier when unmapping all the memory regions. | |
409 | */ | |
9e1b32ca BH |
410 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, |
411 | unsigned long addr) | |
1da177e4 | 412 | { |
2f569afd | 413 | pgtable_t token = pmd_pgtable(*pmd); |
e0da382c | 414 | pmd_clear(pmd); |
9e1b32ca | 415 | pte_free_tlb(tlb, token, addr); |
e0da382c | 416 | tlb->mm->nr_ptes--; |
1da177e4 LT |
417 | } |
418 | ||
e0da382c HD |
419 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
420 | unsigned long addr, unsigned long end, | |
421 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
422 | { |
423 | pmd_t *pmd; | |
424 | unsigned long next; | |
e0da382c | 425 | unsigned long start; |
1da177e4 | 426 | |
e0da382c | 427 | start = addr; |
1da177e4 | 428 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
429 | do { |
430 | next = pmd_addr_end(addr, end); | |
431 | if (pmd_none_or_clear_bad(pmd)) | |
432 | continue; | |
9e1b32ca | 433 | free_pte_range(tlb, pmd, addr); |
1da177e4 LT |
434 | } while (pmd++, addr = next, addr != end); |
435 | ||
e0da382c HD |
436 | start &= PUD_MASK; |
437 | if (start < floor) | |
438 | return; | |
439 | if (ceiling) { | |
440 | ceiling &= PUD_MASK; | |
441 | if (!ceiling) | |
442 | return; | |
1da177e4 | 443 | } |
e0da382c HD |
444 | if (end - 1 > ceiling - 1) |
445 | return; | |
446 | ||
447 | pmd = pmd_offset(pud, start); | |
448 | pud_clear(pud); | |
9e1b32ca | 449 | pmd_free_tlb(tlb, pmd, start); |
1da177e4 LT |
450 | } |
451 | ||
e0da382c HD |
452 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
453 | unsigned long addr, unsigned long end, | |
454 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
455 | { |
456 | pud_t *pud; | |
457 | unsigned long next; | |
e0da382c | 458 | unsigned long start; |
1da177e4 | 459 | |
e0da382c | 460 | start = addr; |
1da177e4 | 461 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
462 | do { |
463 | next = pud_addr_end(addr, end); | |
464 | if (pud_none_or_clear_bad(pud)) | |
465 | continue; | |
e0da382c | 466 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
467 | } while (pud++, addr = next, addr != end); |
468 | ||
e0da382c HD |
469 | start &= PGDIR_MASK; |
470 | if (start < floor) | |
471 | return; | |
472 | if (ceiling) { | |
473 | ceiling &= PGDIR_MASK; | |
474 | if (!ceiling) | |
475 | return; | |
1da177e4 | 476 | } |
e0da382c HD |
477 | if (end - 1 > ceiling - 1) |
478 | return; | |
479 | ||
480 | pud = pud_offset(pgd, start); | |
481 | pgd_clear(pgd); | |
9e1b32ca | 482 | pud_free_tlb(tlb, pud, start); |
1da177e4 LT |
483 | } |
484 | ||
485 | /* | |
e0da382c HD |
486 | * This function frees user-level page tables of a process. |
487 | * | |
1da177e4 LT |
488 | * Must be called with pagetable lock held. |
489 | */ | |
42b77728 | 490 | void free_pgd_range(struct mmu_gather *tlb, |
e0da382c HD |
491 | unsigned long addr, unsigned long end, |
492 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
493 | { |
494 | pgd_t *pgd; | |
495 | unsigned long next; | |
e0da382c HD |
496 | |
497 | /* | |
498 | * The next few lines have given us lots of grief... | |
499 | * | |
500 | * Why are we testing PMD* at this top level? Because often | |
501 | * there will be no work to do at all, and we'd prefer not to | |
502 | * go all the way down to the bottom just to discover that. | |
503 | * | |
504 | * Why all these "- 1"s? Because 0 represents both the bottom | |
505 | * of the address space and the top of it (using -1 for the | |
506 | * top wouldn't help much: the masks would do the wrong thing). | |
507 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
508 | * the address space, but end 0 and ceiling 0 refer to the top | |
509 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
510 | * that end 0 case should be mythical). | |
511 | * | |
512 | * Wherever addr is brought up or ceiling brought down, we must | |
513 | * be careful to reject "the opposite 0" before it confuses the | |
514 | * subsequent tests. But what about where end is brought down | |
515 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
516 | * | |
517 | * Whereas we round start (addr) and ceiling down, by different | |
518 | * masks at different levels, in order to test whether a table | |
519 | * now has no other vmas using it, so can be freed, we don't | |
520 | * bother to round floor or end up - the tests don't need that. | |
521 | */ | |
1da177e4 | 522 | |
e0da382c HD |
523 | addr &= PMD_MASK; |
524 | if (addr < floor) { | |
525 | addr += PMD_SIZE; | |
526 | if (!addr) | |
527 | return; | |
528 | } | |
529 | if (ceiling) { | |
530 | ceiling &= PMD_MASK; | |
531 | if (!ceiling) | |
532 | return; | |
533 | } | |
534 | if (end - 1 > ceiling - 1) | |
535 | end -= PMD_SIZE; | |
536 | if (addr > end - 1) | |
537 | return; | |
538 | ||
42b77728 | 539 | pgd = pgd_offset(tlb->mm, addr); |
1da177e4 LT |
540 | do { |
541 | next = pgd_addr_end(addr, end); | |
542 | if (pgd_none_or_clear_bad(pgd)) | |
543 | continue; | |
42b77728 | 544 | free_pud_range(tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 545 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
546 | } |
547 | ||
42b77728 | 548 | void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3bf5ee95 | 549 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
550 | { |
551 | while (vma) { | |
552 | struct vm_area_struct *next = vma->vm_next; | |
553 | unsigned long addr = vma->vm_start; | |
554 | ||
8f4f8c16 | 555 | /* |
25d9e2d1 | 556 | * Hide vma from rmap and truncate_pagecache before freeing |
557 | * pgtables | |
8f4f8c16 | 558 | */ |
5beb4930 | 559 | unlink_anon_vmas(vma); |
8f4f8c16 HD |
560 | unlink_file_vma(vma); |
561 | ||
9da61aef | 562 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 563 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 564 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
565 | } else { |
566 | /* | |
567 | * Optimization: gather nearby vmas into one call down | |
568 | */ | |
569 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 570 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
571 | vma = next; |
572 | next = vma->vm_next; | |
5beb4930 | 573 | unlink_anon_vmas(vma); |
8f4f8c16 | 574 | unlink_file_vma(vma); |
3bf5ee95 HD |
575 | } |
576 | free_pgd_range(tlb, addr, vma->vm_end, | |
577 | floor, next? next->vm_start: ceiling); | |
578 | } | |
e0da382c HD |
579 | vma = next; |
580 | } | |
1da177e4 LT |
581 | } |
582 | ||
8ac1f832 AA |
583 | int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, |
584 | pmd_t *pmd, unsigned long address) | |
1da177e4 | 585 | { |
2f569afd | 586 | pgtable_t new = pte_alloc_one(mm, address); |
8ac1f832 | 587 | int wait_split_huge_page; |
1bb3630e HD |
588 | if (!new) |
589 | return -ENOMEM; | |
590 | ||
362a61ad NP |
591 | /* |
592 | * Ensure all pte setup (eg. pte page lock and page clearing) are | |
593 | * visible before the pte is made visible to other CPUs by being | |
594 | * put into page tables. | |
595 | * | |
596 | * The other side of the story is the pointer chasing in the page | |
597 | * table walking code (when walking the page table without locking; | |
598 | * ie. most of the time). Fortunately, these data accesses consist | |
599 | * of a chain of data-dependent loads, meaning most CPUs (alpha | |
600 | * being the notable exception) will already guarantee loads are | |
601 | * seen in-order. See the alpha page table accessors for the | |
602 | * smp_read_barrier_depends() barriers in page table walking code. | |
603 | */ | |
604 | smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ | |
605 | ||
c74df32c | 606 | spin_lock(&mm->page_table_lock); |
8ac1f832 AA |
607 | wait_split_huge_page = 0; |
608 | if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ | |
1da177e4 | 609 | mm->nr_ptes++; |
1da177e4 | 610 | pmd_populate(mm, pmd, new); |
2f569afd | 611 | new = NULL; |
8ac1f832 AA |
612 | } else if (unlikely(pmd_trans_splitting(*pmd))) |
613 | wait_split_huge_page = 1; | |
c74df32c | 614 | spin_unlock(&mm->page_table_lock); |
2f569afd MS |
615 | if (new) |
616 | pte_free(mm, new); | |
8ac1f832 AA |
617 | if (wait_split_huge_page) |
618 | wait_split_huge_page(vma->anon_vma, pmd); | |
1bb3630e | 619 | return 0; |
1da177e4 LT |
620 | } |
621 | ||
1bb3630e | 622 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 623 | { |
1bb3630e HD |
624 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
625 | if (!new) | |
626 | return -ENOMEM; | |
627 | ||
362a61ad NP |
628 | smp_wmb(); /* See comment in __pte_alloc */ |
629 | ||
1bb3630e | 630 | spin_lock(&init_mm.page_table_lock); |
8ac1f832 | 631 | if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ |
1bb3630e | 632 | pmd_populate_kernel(&init_mm, pmd, new); |
2f569afd | 633 | new = NULL; |
8ac1f832 AA |
634 | } else |
635 | VM_BUG_ON(pmd_trans_splitting(*pmd)); | |
1bb3630e | 636 | spin_unlock(&init_mm.page_table_lock); |
2f569afd MS |
637 | if (new) |
638 | pte_free_kernel(&init_mm, new); | |
1bb3630e | 639 | return 0; |
1da177e4 LT |
640 | } |
641 | ||
d559db08 KH |
642 | static inline void init_rss_vec(int *rss) |
643 | { | |
644 | memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); | |
645 | } | |
646 | ||
647 | static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) | |
ae859762 | 648 | { |
d559db08 KH |
649 | int i; |
650 | ||
34e55232 | 651 | if (current->mm == mm) |
05af2e10 | 652 | sync_mm_rss(mm); |
d559db08 KH |
653 | for (i = 0; i < NR_MM_COUNTERS; i++) |
654 | if (rss[i]) | |
655 | add_mm_counter(mm, i, rss[i]); | |
ae859762 HD |
656 | } |
657 | ||
b5810039 | 658 | /* |
6aab341e LT |
659 | * This function is called to print an error when a bad pte |
660 | * is found. For example, we might have a PFN-mapped pte in | |
661 | * a region that doesn't allow it. | |
b5810039 NP |
662 | * |
663 | * The calling function must still handle the error. | |
664 | */ | |
3dc14741 HD |
665 | static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, |
666 | pte_t pte, struct page *page) | |
b5810039 | 667 | { |
3dc14741 HD |
668 | pgd_t *pgd = pgd_offset(vma->vm_mm, addr); |
669 | pud_t *pud = pud_offset(pgd, addr); | |
670 | pmd_t *pmd = pmd_offset(pud, addr); | |
671 | struct address_space *mapping; | |
672 | pgoff_t index; | |
d936cf9b HD |
673 | static unsigned long resume; |
674 | static unsigned long nr_shown; | |
675 | static unsigned long nr_unshown; | |
676 | ||
677 | /* | |
678 | * Allow a burst of 60 reports, then keep quiet for that minute; | |
679 | * or allow a steady drip of one report per second. | |
680 | */ | |
681 | if (nr_shown == 60) { | |
682 | if (time_before(jiffies, resume)) { | |
683 | nr_unshown++; | |
684 | return; | |
685 | } | |
686 | if (nr_unshown) { | |
1e9e6365 HD |
687 | printk(KERN_ALERT |
688 | "BUG: Bad page map: %lu messages suppressed\n", | |
d936cf9b HD |
689 | nr_unshown); |
690 | nr_unshown = 0; | |
691 | } | |
692 | nr_shown = 0; | |
693 | } | |
694 | if (nr_shown++ == 0) | |
695 | resume = jiffies + 60 * HZ; | |
3dc14741 HD |
696 | |
697 | mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; | |
698 | index = linear_page_index(vma, addr); | |
699 | ||
1e9e6365 HD |
700 | printk(KERN_ALERT |
701 | "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", | |
3dc14741 HD |
702 | current->comm, |
703 | (long long)pte_val(pte), (long long)pmd_val(*pmd)); | |
718a3821 WF |
704 | if (page) |
705 | dump_page(page); | |
1e9e6365 | 706 | printk(KERN_ALERT |
3dc14741 HD |
707 | "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", |
708 | (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); | |
709 | /* | |
710 | * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y | |
711 | */ | |
712 | if (vma->vm_ops) | |
1e9e6365 | 713 | print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n", |
3dc14741 HD |
714 | (unsigned long)vma->vm_ops->fault); |
715 | if (vma->vm_file && vma->vm_file->f_op) | |
1e9e6365 | 716 | print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n", |
3dc14741 | 717 | (unsigned long)vma->vm_file->f_op->mmap); |
b5810039 | 718 | dump_stack(); |
3dc14741 | 719 | add_taint(TAINT_BAD_PAGE); |
b5810039 NP |
720 | } |
721 | ||
2ec74c3e | 722 | static inline bool is_cow_mapping(vm_flags_t flags) |
67121172 LT |
723 | { |
724 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
725 | } | |
726 | ||
ee498ed7 | 727 | /* |
7e675137 | 728 | * vm_normal_page -- This function gets the "struct page" associated with a pte. |
6aab341e | 729 | * |
7e675137 NP |
730 | * "Special" mappings do not wish to be associated with a "struct page" (either |
731 | * it doesn't exist, or it exists but they don't want to touch it). In this | |
732 | * case, NULL is returned here. "Normal" mappings do have a struct page. | |
b379d790 | 733 | * |
7e675137 NP |
734 | * There are 2 broad cases. Firstly, an architecture may define a pte_special() |
735 | * pte bit, in which case this function is trivial. Secondly, an architecture | |
736 | * may not have a spare pte bit, which requires a more complicated scheme, | |
737 | * described below. | |
738 | * | |
739 | * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a | |
740 | * special mapping (even if there are underlying and valid "struct pages"). | |
741 | * COWed pages of a VM_PFNMAP are always normal. | |
6aab341e | 742 | * |
b379d790 JH |
743 | * The way we recognize COWed pages within VM_PFNMAP mappings is through the |
744 | * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit | |
7e675137 NP |
745 | * set, and the vm_pgoff will point to the first PFN mapped: thus every special |
746 | * mapping will always honor the rule | |
6aab341e LT |
747 | * |
748 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
749 | * | |
7e675137 NP |
750 | * And for normal mappings this is false. |
751 | * | |
752 | * This restricts such mappings to be a linear translation from virtual address | |
753 | * to pfn. To get around this restriction, we allow arbitrary mappings so long | |
754 | * as the vma is not a COW mapping; in that case, we know that all ptes are | |
755 | * special (because none can have been COWed). | |
b379d790 | 756 | * |
b379d790 | 757 | * |
7e675137 | 758 | * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. |
b379d790 JH |
759 | * |
760 | * VM_MIXEDMAP mappings can likewise contain memory with or without "struct | |
761 | * page" backing, however the difference is that _all_ pages with a struct | |
762 | * page (that is, those where pfn_valid is true) are refcounted and considered | |
763 | * normal pages by the VM. The disadvantage is that pages are refcounted | |
764 | * (which can be slower and simply not an option for some PFNMAP users). The | |
765 | * advantage is that we don't have to follow the strict linearity rule of | |
766 | * PFNMAP mappings in order to support COWable mappings. | |
767 | * | |
ee498ed7 | 768 | */ |
7e675137 NP |
769 | #ifdef __HAVE_ARCH_PTE_SPECIAL |
770 | # define HAVE_PTE_SPECIAL 1 | |
771 | #else | |
772 | # define HAVE_PTE_SPECIAL 0 | |
773 | #endif | |
774 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, | |
775 | pte_t pte) | |
ee498ed7 | 776 | { |
22b31eec | 777 | unsigned long pfn = pte_pfn(pte); |
7e675137 NP |
778 | |
779 | if (HAVE_PTE_SPECIAL) { | |
22b31eec HD |
780 | if (likely(!pte_special(pte))) |
781 | goto check_pfn; | |
a13ea5b7 HD |
782 | if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) |
783 | return NULL; | |
62eede62 | 784 | if (!is_zero_pfn(pfn)) |
22b31eec | 785 | print_bad_pte(vma, addr, pte, NULL); |
7e675137 NP |
786 | return NULL; |
787 | } | |
788 | ||
789 | /* !HAVE_PTE_SPECIAL case follows: */ | |
790 | ||
b379d790 JH |
791 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { |
792 | if (vma->vm_flags & VM_MIXEDMAP) { | |
793 | if (!pfn_valid(pfn)) | |
794 | return NULL; | |
795 | goto out; | |
796 | } else { | |
7e675137 NP |
797 | unsigned long off; |
798 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
b379d790 JH |
799 | if (pfn == vma->vm_pgoff + off) |
800 | return NULL; | |
801 | if (!is_cow_mapping(vma->vm_flags)) | |
802 | return NULL; | |
803 | } | |
6aab341e LT |
804 | } |
805 | ||
62eede62 HD |
806 | if (is_zero_pfn(pfn)) |
807 | return NULL; | |
22b31eec HD |
808 | check_pfn: |
809 | if (unlikely(pfn > highest_memmap_pfn)) { | |
810 | print_bad_pte(vma, addr, pte, NULL); | |
811 | return NULL; | |
812 | } | |
6aab341e LT |
813 | |
814 | /* | |
7e675137 | 815 | * NOTE! We still have PageReserved() pages in the page tables. |
7e675137 | 816 | * eg. VDSO mappings can cause them to exist. |
6aab341e | 817 | */ |
b379d790 | 818 | out: |
6aab341e | 819 | return pfn_to_page(pfn); |
ee498ed7 HD |
820 | } |
821 | ||
1da177e4 LT |
822 | /* |
823 | * copy one vm_area from one task to the other. Assumes the page tables | |
824 | * already present in the new task to be cleared in the whole range | |
825 | * covered by this vma. | |
1da177e4 LT |
826 | */ |
827 | ||
570a335b | 828 | static inline unsigned long |
1da177e4 | 829 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 830 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 831 | unsigned long addr, int *rss) |
1da177e4 | 832 | { |
b5810039 | 833 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
834 | pte_t pte = *src_pte; |
835 | struct page *page; | |
1da177e4 LT |
836 | |
837 | /* pte contains position in swap or file, so copy. */ | |
838 | if (unlikely(!pte_present(pte))) { | |
839 | if (!pte_file(pte)) { | |
0697212a CL |
840 | swp_entry_t entry = pte_to_swp_entry(pte); |
841 | ||
570a335b HD |
842 | if (swap_duplicate(entry) < 0) |
843 | return entry.val; | |
844 | ||
1da177e4 LT |
845 | /* make sure dst_mm is on swapoff's mmlist. */ |
846 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
847 | spin_lock(&mmlist_lock); | |
f412ac08 HD |
848 | if (list_empty(&dst_mm->mmlist)) |
849 | list_add(&dst_mm->mmlist, | |
850 | &src_mm->mmlist); | |
1da177e4 LT |
851 | spin_unlock(&mmlist_lock); |
852 | } | |
b084d435 KH |
853 | if (likely(!non_swap_entry(entry))) |
854 | rss[MM_SWAPENTS]++; | |
9f9f1acd KK |
855 | else if (is_migration_entry(entry)) { |
856 | page = migration_entry_to_page(entry); | |
857 | ||
858 | if (PageAnon(page)) | |
859 | rss[MM_ANONPAGES]++; | |
860 | else | |
861 | rss[MM_FILEPAGES]++; | |
862 | ||
863 | if (is_write_migration_entry(entry) && | |
864 | is_cow_mapping(vm_flags)) { | |
865 | /* | |
866 | * COW mappings require pages in both | |
867 | * parent and child to be set to read. | |
868 | */ | |
869 | make_migration_entry_read(&entry); | |
870 | pte = swp_entry_to_pte(entry); | |
871 | set_pte_at(src_mm, addr, src_pte, pte); | |
872 | } | |
0697212a | 873 | } |
1da177e4 | 874 | } |
ae859762 | 875 | goto out_set_pte; |
1da177e4 LT |
876 | } |
877 | ||
1da177e4 LT |
878 | /* |
879 | * If it's a COW mapping, write protect it both | |
880 | * in the parent and the child | |
881 | */ | |
67121172 | 882 | if (is_cow_mapping(vm_flags)) { |
1da177e4 | 883 | ptep_set_wrprotect(src_mm, addr, src_pte); |
3dc90795 | 884 | pte = pte_wrprotect(pte); |
1da177e4 LT |
885 | } |
886 | ||
887 | /* | |
888 | * If it's a shared mapping, mark it clean in | |
889 | * the child | |
890 | */ | |
891 | if (vm_flags & VM_SHARED) | |
892 | pte = pte_mkclean(pte); | |
893 | pte = pte_mkold(pte); | |
6aab341e LT |
894 | |
895 | page = vm_normal_page(vma, addr, pte); | |
896 | if (page) { | |
897 | get_page(page); | |
21333b2b | 898 | page_dup_rmap(page); |
d559db08 KH |
899 | if (PageAnon(page)) |
900 | rss[MM_ANONPAGES]++; | |
901 | else | |
902 | rss[MM_FILEPAGES]++; | |
6aab341e | 903 | } |
ae859762 HD |
904 | |
905 | out_set_pte: | |
906 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
570a335b | 907 | return 0; |
1da177e4 LT |
908 | } |
909 | ||
71e3aac0 AA |
910 | int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
911 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, | |
912 | unsigned long addr, unsigned long end) | |
1da177e4 | 913 | { |
c36987e2 | 914 | pte_t *orig_src_pte, *orig_dst_pte; |
1da177e4 | 915 | pte_t *src_pte, *dst_pte; |
c74df32c | 916 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 917 | int progress = 0; |
d559db08 | 918 | int rss[NR_MM_COUNTERS]; |
570a335b | 919 | swp_entry_t entry = (swp_entry_t){0}; |
1da177e4 LT |
920 | |
921 | again: | |
d559db08 KH |
922 | init_rss_vec(rss); |
923 | ||
c74df32c | 924 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
925 | if (!dst_pte) |
926 | return -ENOMEM; | |
ece0e2b6 | 927 | src_pte = pte_offset_map(src_pmd, addr); |
4c21e2f2 | 928 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 929 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
c36987e2 DN |
930 | orig_src_pte = src_pte; |
931 | orig_dst_pte = dst_pte; | |
6606c3e0 | 932 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 933 | |
1da177e4 LT |
934 | do { |
935 | /* | |
936 | * We are holding two locks at this point - either of them | |
937 | * could generate latencies in another task on another CPU. | |
938 | */ | |
e040f218 HD |
939 | if (progress >= 32) { |
940 | progress = 0; | |
941 | if (need_resched() || | |
95c354fe | 942 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
943 | break; |
944 | } | |
1da177e4 LT |
945 | if (pte_none(*src_pte)) { |
946 | progress++; | |
947 | continue; | |
948 | } | |
570a335b HD |
949 | entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, |
950 | vma, addr, rss); | |
951 | if (entry.val) | |
952 | break; | |
1da177e4 LT |
953 | progress += 8; |
954 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 955 | |
6606c3e0 | 956 | arch_leave_lazy_mmu_mode(); |
c74df32c | 957 | spin_unlock(src_ptl); |
ece0e2b6 | 958 | pte_unmap(orig_src_pte); |
d559db08 | 959 | add_mm_rss_vec(dst_mm, rss); |
c36987e2 | 960 | pte_unmap_unlock(orig_dst_pte, dst_ptl); |
c74df32c | 961 | cond_resched(); |
570a335b HD |
962 | |
963 | if (entry.val) { | |
964 | if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) | |
965 | return -ENOMEM; | |
966 | progress = 0; | |
967 | } | |
1da177e4 LT |
968 | if (addr != end) |
969 | goto again; | |
970 | return 0; | |
971 | } | |
972 | ||
973 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
974 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
975 | unsigned long addr, unsigned long end) | |
976 | { | |
977 | pmd_t *src_pmd, *dst_pmd; | |
978 | unsigned long next; | |
979 | ||
980 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
981 | if (!dst_pmd) | |
982 | return -ENOMEM; | |
983 | src_pmd = pmd_offset(src_pud, addr); | |
984 | do { | |
985 | next = pmd_addr_end(addr, end); | |
71e3aac0 AA |
986 | if (pmd_trans_huge(*src_pmd)) { |
987 | int err; | |
14d1a55c | 988 | VM_BUG_ON(next-addr != HPAGE_PMD_SIZE); |
71e3aac0 AA |
989 | err = copy_huge_pmd(dst_mm, src_mm, |
990 | dst_pmd, src_pmd, addr, vma); | |
991 | if (err == -ENOMEM) | |
992 | return -ENOMEM; | |
993 | if (!err) | |
994 | continue; | |
995 | /* fall through */ | |
996 | } | |
1da177e4 LT |
997 | if (pmd_none_or_clear_bad(src_pmd)) |
998 | continue; | |
999 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
1000 | vma, addr, next)) | |
1001 | return -ENOMEM; | |
1002 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
1003 | return 0; | |
1004 | } | |
1005 | ||
1006 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1007 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
1008 | unsigned long addr, unsigned long end) | |
1009 | { | |
1010 | pud_t *src_pud, *dst_pud; | |
1011 | unsigned long next; | |
1012 | ||
1013 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
1014 | if (!dst_pud) | |
1015 | return -ENOMEM; | |
1016 | src_pud = pud_offset(src_pgd, addr); | |
1017 | do { | |
1018 | next = pud_addr_end(addr, end); | |
1019 | if (pud_none_or_clear_bad(src_pud)) | |
1020 | continue; | |
1021 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
1022 | vma, addr, next)) | |
1023 | return -ENOMEM; | |
1024 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
1025 | return 0; | |
1026 | } | |
1027 | ||
1028 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1029 | struct vm_area_struct *vma) | |
1030 | { | |
1031 | pgd_t *src_pgd, *dst_pgd; | |
1032 | unsigned long next; | |
1033 | unsigned long addr = vma->vm_start; | |
1034 | unsigned long end = vma->vm_end; | |
2ec74c3e SG |
1035 | unsigned long mmun_start; /* For mmu_notifiers */ |
1036 | unsigned long mmun_end; /* For mmu_notifiers */ | |
1037 | bool is_cow; | |
cddb8a5c | 1038 | int ret; |
1da177e4 | 1039 | |
d992895b NP |
1040 | /* |
1041 | * Don't copy ptes where a page fault will fill them correctly. | |
1042 | * Fork becomes much lighter when there are big shared or private | |
1043 | * readonly mappings. The tradeoff is that copy_page_range is more | |
1044 | * efficient than faulting. | |
1045 | */ | |
4b6e1e37 KK |
1046 | if (!(vma->vm_flags & (VM_HUGETLB | VM_NONLINEAR | |
1047 | VM_PFNMAP | VM_MIXEDMAP))) { | |
d992895b NP |
1048 | if (!vma->anon_vma) |
1049 | return 0; | |
1050 | } | |
1051 | ||
1da177e4 LT |
1052 | if (is_vm_hugetlb_page(vma)) |
1053 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
1054 | ||
b3b9c293 | 1055 | if (unlikely(vma->vm_flags & VM_PFNMAP)) { |
2ab64037 | 1056 | /* |
1057 | * We do not free on error cases below as remove_vma | |
1058 | * gets called on error from higher level routine | |
1059 | */ | |
5180da41 | 1060 | ret = track_pfn_copy(vma); |
2ab64037 | 1061 | if (ret) |
1062 | return ret; | |
1063 | } | |
1064 | ||
cddb8a5c AA |
1065 | /* |
1066 | * We need to invalidate the secondary MMU mappings only when | |
1067 | * there could be a permission downgrade on the ptes of the | |
1068 | * parent mm. And a permission downgrade will only happen if | |
1069 | * is_cow_mapping() returns true. | |
1070 | */ | |
2ec74c3e SG |
1071 | is_cow = is_cow_mapping(vma->vm_flags); |
1072 | mmun_start = addr; | |
1073 | mmun_end = end; | |
1074 | if (is_cow) | |
1075 | mmu_notifier_invalidate_range_start(src_mm, mmun_start, | |
1076 | mmun_end); | |
cddb8a5c AA |
1077 | |
1078 | ret = 0; | |
1da177e4 LT |
1079 | dst_pgd = pgd_offset(dst_mm, addr); |
1080 | src_pgd = pgd_offset(src_mm, addr); | |
1081 | do { | |
1082 | next = pgd_addr_end(addr, end); | |
1083 | if (pgd_none_or_clear_bad(src_pgd)) | |
1084 | continue; | |
cddb8a5c AA |
1085 | if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
1086 | vma, addr, next))) { | |
1087 | ret = -ENOMEM; | |
1088 | break; | |
1089 | } | |
1da177e4 | 1090 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
cddb8a5c | 1091 | |
2ec74c3e SG |
1092 | if (is_cow) |
1093 | mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end); | |
cddb8a5c | 1094 | return ret; |
1da177e4 LT |
1095 | } |
1096 | ||
51c6f666 | 1097 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 1098 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 1099 | unsigned long addr, unsigned long end, |
97a89413 | 1100 | struct zap_details *details) |
1da177e4 | 1101 | { |
b5810039 | 1102 | struct mm_struct *mm = tlb->mm; |
d16dfc55 | 1103 | int force_flush = 0; |
d559db08 | 1104 | int rss[NR_MM_COUNTERS]; |
97a89413 | 1105 | spinlock_t *ptl; |
5f1a1907 | 1106 | pte_t *start_pte; |
97a89413 | 1107 | pte_t *pte; |
d559db08 | 1108 | |
d16dfc55 | 1109 | again: |
e303297e | 1110 | init_rss_vec(rss); |
5f1a1907 SR |
1111 | start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
1112 | pte = start_pte; | |
6606c3e0 | 1113 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1114 | do { |
1115 | pte_t ptent = *pte; | |
51c6f666 | 1116 | if (pte_none(ptent)) { |
1da177e4 | 1117 | continue; |
51c6f666 | 1118 | } |
6f5e6b9e | 1119 | |
1da177e4 | 1120 | if (pte_present(ptent)) { |
ee498ed7 | 1121 | struct page *page; |
51c6f666 | 1122 | |
6aab341e | 1123 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
1124 | if (unlikely(details) && page) { |
1125 | /* | |
1126 | * unmap_shared_mapping_pages() wants to | |
1127 | * invalidate cache without truncating: | |
1128 | * unmap shared but keep private pages. | |
1129 | */ | |
1130 | if (details->check_mapping && | |
1131 | details->check_mapping != page->mapping) | |
1132 | continue; | |
1133 | /* | |
1134 | * Each page->index must be checked when | |
1135 | * invalidating or truncating nonlinear. | |
1136 | */ | |
1137 | if (details->nonlinear_vma && | |
1138 | (page->index < details->first_index || | |
1139 | page->index > details->last_index)) | |
1140 | continue; | |
1141 | } | |
b5810039 | 1142 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 1143 | tlb->fullmm); |
1da177e4 LT |
1144 | tlb_remove_tlb_entry(tlb, pte, addr); |
1145 | if (unlikely(!page)) | |
1146 | continue; | |
1147 | if (unlikely(details) && details->nonlinear_vma | |
1148 | && linear_page_index(details->nonlinear_vma, | |
1149 | addr) != page->index) | |
b5810039 | 1150 | set_pte_at(mm, addr, pte, |
1da177e4 | 1151 | pgoff_to_pte(page->index)); |
1da177e4 | 1152 | if (PageAnon(page)) |
d559db08 | 1153 | rss[MM_ANONPAGES]--; |
6237bcd9 HD |
1154 | else { |
1155 | if (pte_dirty(ptent)) | |
1156 | set_page_dirty(page); | |
4917e5d0 JW |
1157 | if (pte_young(ptent) && |
1158 | likely(!VM_SequentialReadHint(vma))) | |
bf3f3bc5 | 1159 | mark_page_accessed(page); |
d559db08 | 1160 | rss[MM_FILEPAGES]--; |
6237bcd9 | 1161 | } |
edc315fd | 1162 | page_remove_rmap(page); |
3dc14741 HD |
1163 | if (unlikely(page_mapcount(page) < 0)) |
1164 | print_bad_pte(vma, addr, ptent, page); | |
d16dfc55 PZ |
1165 | force_flush = !__tlb_remove_page(tlb, page); |
1166 | if (force_flush) | |
1167 | break; | |
1da177e4 LT |
1168 | continue; |
1169 | } | |
1170 | /* | |
1171 | * If details->check_mapping, we leave swap entries; | |
1172 | * if details->nonlinear_vma, we leave file entries. | |
1173 | */ | |
1174 | if (unlikely(details)) | |
1175 | continue; | |
2509ef26 HD |
1176 | if (pte_file(ptent)) { |
1177 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) | |
1178 | print_bad_pte(vma, addr, ptent, NULL); | |
b084d435 KH |
1179 | } else { |
1180 | swp_entry_t entry = pte_to_swp_entry(ptent); | |
1181 | ||
1182 | if (!non_swap_entry(entry)) | |
1183 | rss[MM_SWAPENTS]--; | |
9f9f1acd KK |
1184 | else if (is_migration_entry(entry)) { |
1185 | struct page *page; | |
1186 | ||
1187 | page = migration_entry_to_page(entry); | |
1188 | ||
1189 | if (PageAnon(page)) | |
1190 | rss[MM_ANONPAGES]--; | |
1191 | else | |
1192 | rss[MM_FILEPAGES]--; | |
1193 | } | |
b084d435 KH |
1194 | if (unlikely(!free_swap_and_cache(entry))) |
1195 | print_bad_pte(vma, addr, ptent, NULL); | |
1196 | } | |
9888a1ca | 1197 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); |
97a89413 | 1198 | } while (pte++, addr += PAGE_SIZE, addr != end); |
ae859762 | 1199 | |
d559db08 | 1200 | add_mm_rss_vec(mm, rss); |
6606c3e0 | 1201 | arch_leave_lazy_mmu_mode(); |
5f1a1907 | 1202 | pte_unmap_unlock(start_pte, ptl); |
51c6f666 | 1203 | |
d16dfc55 PZ |
1204 | /* |
1205 | * mmu_gather ran out of room to batch pages, we break out of | |
1206 | * the PTE lock to avoid doing the potential expensive TLB invalidate | |
1207 | * and page-free while holding it. | |
1208 | */ | |
1209 | if (force_flush) { | |
1210 | force_flush = 0; | |
597e1c35 AS |
1211 | |
1212 | #ifdef HAVE_GENERIC_MMU_GATHER | |
1213 | tlb->start = addr; | |
1214 | tlb->end = end; | |
1215 | #endif | |
d16dfc55 PZ |
1216 | tlb_flush_mmu(tlb); |
1217 | if (addr != end) | |
1218 | goto again; | |
1219 | } | |
1220 | ||
51c6f666 | 1221 | return addr; |
1da177e4 LT |
1222 | } |
1223 | ||
51c6f666 | 1224 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 1225 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 1226 | unsigned long addr, unsigned long end, |
97a89413 | 1227 | struct zap_details *details) |
1da177e4 LT |
1228 | { |
1229 | pmd_t *pmd; | |
1230 | unsigned long next; | |
1231 | ||
1232 | pmd = pmd_offset(pud, addr); | |
1233 | do { | |
1234 | next = pmd_addr_end(addr, end); | |
71e3aac0 | 1235 | if (pmd_trans_huge(*pmd)) { |
1a5a9906 | 1236 | if (next - addr != HPAGE_PMD_SIZE) { |
e0897d75 DR |
1237 | #ifdef CONFIG_DEBUG_VM |
1238 | if (!rwsem_is_locked(&tlb->mm->mmap_sem)) { | |
1239 | pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n", | |
1240 | __func__, addr, end, | |
1241 | vma->vm_start, | |
1242 | vma->vm_end); | |
1243 | BUG(); | |
1244 | } | |
1245 | #endif | |
e180377f | 1246 | split_huge_page_pmd(vma, addr, pmd); |
f21760b1 | 1247 | } else if (zap_huge_pmd(tlb, vma, pmd, addr)) |
1a5a9906 | 1248 | goto next; |
71e3aac0 AA |
1249 | /* fall through */ |
1250 | } | |
1a5a9906 AA |
1251 | /* |
1252 | * Here there can be other concurrent MADV_DONTNEED or | |
1253 | * trans huge page faults running, and if the pmd is | |
1254 | * none or trans huge it can change under us. This is | |
1255 | * because MADV_DONTNEED holds the mmap_sem in read | |
1256 | * mode. | |
1257 | */ | |
1258 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) | |
1259 | goto next; | |
97a89413 | 1260 | next = zap_pte_range(tlb, vma, pmd, addr, next, details); |
1a5a9906 | 1261 | next: |
97a89413 PZ |
1262 | cond_resched(); |
1263 | } while (pmd++, addr = next, addr != end); | |
51c6f666 RH |
1264 | |
1265 | return addr; | |
1da177e4 LT |
1266 | } |
1267 | ||
51c6f666 | 1268 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 1269 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 1270 | unsigned long addr, unsigned long end, |
97a89413 | 1271 | struct zap_details *details) |
1da177e4 LT |
1272 | { |
1273 | pud_t *pud; | |
1274 | unsigned long next; | |
1275 | ||
1276 | pud = pud_offset(pgd, addr); | |
1277 | do { | |
1278 | next = pud_addr_end(addr, end); | |
97a89413 | 1279 | if (pud_none_or_clear_bad(pud)) |
1da177e4 | 1280 | continue; |
97a89413 PZ |
1281 | next = zap_pmd_range(tlb, vma, pud, addr, next, details); |
1282 | } while (pud++, addr = next, addr != end); | |
51c6f666 RH |
1283 | |
1284 | return addr; | |
1da177e4 LT |
1285 | } |
1286 | ||
038c7aa1 AV |
1287 | static void unmap_page_range(struct mmu_gather *tlb, |
1288 | struct vm_area_struct *vma, | |
1289 | unsigned long addr, unsigned long end, | |
1290 | struct zap_details *details) | |
1da177e4 LT |
1291 | { |
1292 | pgd_t *pgd; | |
1293 | unsigned long next; | |
1294 | ||
1295 | if (details && !details->check_mapping && !details->nonlinear_vma) | |
1296 | details = NULL; | |
1297 | ||
1298 | BUG_ON(addr >= end); | |
569b846d | 1299 | mem_cgroup_uncharge_start(); |
1da177e4 LT |
1300 | tlb_start_vma(tlb, vma); |
1301 | pgd = pgd_offset(vma->vm_mm, addr); | |
1302 | do { | |
1303 | next = pgd_addr_end(addr, end); | |
97a89413 | 1304 | if (pgd_none_or_clear_bad(pgd)) |
1da177e4 | 1305 | continue; |
97a89413 PZ |
1306 | next = zap_pud_range(tlb, vma, pgd, addr, next, details); |
1307 | } while (pgd++, addr = next, addr != end); | |
1da177e4 | 1308 | tlb_end_vma(tlb, vma); |
569b846d | 1309 | mem_cgroup_uncharge_end(); |
1da177e4 | 1310 | } |
51c6f666 | 1311 | |
f5cc4eef AV |
1312 | |
1313 | static void unmap_single_vma(struct mmu_gather *tlb, | |
1314 | struct vm_area_struct *vma, unsigned long start_addr, | |
4f74d2c8 | 1315 | unsigned long end_addr, |
f5cc4eef AV |
1316 | struct zap_details *details) |
1317 | { | |
1318 | unsigned long start = max(vma->vm_start, start_addr); | |
1319 | unsigned long end; | |
1320 | ||
1321 | if (start >= vma->vm_end) | |
1322 | return; | |
1323 | end = min(vma->vm_end, end_addr); | |
1324 | if (end <= vma->vm_start) | |
1325 | return; | |
1326 | ||
cbc91f71 SD |
1327 | if (vma->vm_file) |
1328 | uprobe_munmap(vma, start, end); | |
1329 | ||
b3b9c293 | 1330 | if (unlikely(vma->vm_flags & VM_PFNMAP)) |
5180da41 | 1331 | untrack_pfn(vma, 0, 0); |
f5cc4eef AV |
1332 | |
1333 | if (start != end) { | |
1334 | if (unlikely(is_vm_hugetlb_page(vma))) { | |
1335 | /* | |
1336 | * It is undesirable to test vma->vm_file as it | |
1337 | * should be non-null for valid hugetlb area. | |
1338 | * However, vm_file will be NULL in the error | |
1339 | * cleanup path of do_mmap_pgoff. When | |
1340 | * hugetlbfs ->mmap method fails, | |
1341 | * do_mmap_pgoff() nullifies vma->vm_file | |
1342 | * before calling this function to clean up. | |
1343 | * Since no pte has actually been setup, it is | |
1344 | * safe to do nothing in this case. | |
1345 | */ | |
24669e58 AK |
1346 | if (vma->vm_file) { |
1347 | mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex); | |
d833352a | 1348 | __unmap_hugepage_range_final(tlb, vma, start, end, NULL); |
24669e58 AK |
1349 | mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex); |
1350 | } | |
f5cc4eef AV |
1351 | } else |
1352 | unmap_page_range(tlb, vma, start, end, details); | |
1353 | } | |
1da177e4 LT |
1354 | } |
1355 | ||
1da177e4 LT |
1356 | /** |
1357 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
0164f69d | 1358 | * @tlb: address of the caller's struct mmu_gather |
1da177e4 LT |
1359 | * @vma: the starting vma |
1360 | * @start_addr: virtual address at which to start unmapping | |
1361 | * @end_addr: virtual address at which to end unmapping | |
1da177e4 | 1362 | * |
508034a3 | 1363 | * Unmap all pages in the vma list. |
1da177e4 | 1364 | * |
1da177e4 LT |
1365 | * Only addresses between `start' and `end' will be unmapped. |
1366 | * | |
1367 | * The VMA list must be sorted in ascending virtual address order. | |
1368 | * | |
1369 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
1370 | * range after unmap_vmas() returns. So the only responsibility here is to | |
1371 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
1372 | * drops the lock and schedules. | |
1373 | */ | |
6e8bb019 | 1374 | void unmap_vmas(struct mmu_gather *tlb, |
1da177e4 | 1375 | struct vm_area_struct *vma, unsigned long start_addr, |
4f74d2c8 | 1376 | unsigned long end_addr) |
1da177e4 | 1377 | { |
cddb8a5c | 1378 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1379 | |
cddb8a5c | 1380 | mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); |
f5cc4eef | 1381 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) |
4f74d2c8 | 1382 | unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); |
cddb8a5c | 1383 | mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); |
1da177e4 LT |
1384 | } |
1385 | ||
1386 | /** | |
1387 | * zap_page_range - remove user pages in a given range | |
1388 | * @vma: vm_area_struct holding the applicable pages | |
eb4546bb | 1389 | * @start: starting address of pages to zap |
1da177e4 LT |
1390 | * @size: number of bytes to zap |
1391 | * @details: details of nonlinear truncation or shared cache invalidation | |
f5cc4eef AV |
1392 | * |
1393 | * Caller must protect the VMA list | |
1da177e4 | 1394 | */ |
7e027b14 | 1395 | void zap_page_range(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
1396 | unsigned long size, struct zap_details *details) |
1397 | { | |
1398 | struct mm_struct *mm = vma->vm_mm; | |
d16dfc55 | 1399 | struct mmu_gather tlb; |
7e027b14 | 1400 | unsigned long end = start + size; |
1da177e4 | 1401 | |
1da177e4 | 1402 | lru_add_drain(); |
d16dfc55 | 1403 | tlb_gather_mmu(&tlb, mm, 0); |
365e9c87 | 1404 | update_hiwater_rss(mm); |
7e027b14 LT |
1405 | mmu_notifier_invalidate_range_start(mm, start, end); |
1406 | for ( ; vma && vma->vm_start < end; vma = vma->vm_next) | |
4f74d2c8 | 1407 | unmap_single_vma(&tlb, vma, start, end, details); |
7e027b14 LT |
1408 | mmu_notifier_invalidate_range_end(mm, start, end); |
1409 | tlb_finish_mmu(&tlb, start, end); | |
1da177e4 LT |
1410 | } |
1411 | ||
f5cc4eef AV |
1412 | /** |
1413 | * zap_page_range_single - remove user pages in a given range | |
1414 | * @vma: vm_area_struct holding the applicable pages | |
1415 | * @address: starting address of pages to zap | |
1416 | * @size: number of bytes to zap | |
1417 | * @details: details of nonlinear truncation or shared cache invalidation | |
1418 | * | |
1419 | * The range must fit into one VMA. | |
1da177e4 | 1420 | */ |
f5cc4eef | 1421 | static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
1422 | unsigned long size, struct zap_details *details) |
1423 | { | |
1424 | struct mm_struct *mm = vma->vm_mm; | |
d16dfc55 | 1425 | struct mmu_gather tlb; |
1da177e4 | 1426 | unsigned long end = address + size; |
1da177e4 | 1427 | |
1da177e4 | 1428 | lru_add_drain(); |
d16dfc55 | 1429 | tlb_gather_mmu(&tlb, mm, 0); |
365e9c87 | 1430 | update_hiwater_rss(mm); |
f5cc4eef | 1431 | mmu_notifier_invalidate_range_start(mm, address, end); |
4f74d2c8 | 1432 | unmap_single_vma(&tlb, vma, address, end, details); |
f5cc4eef | 1433 | mmu_notifier_invalidate_range_end(mm, address, end); |
d16dfc55 | 1434 | tlb_finish_mmu(&tlb, address, end); |
1da177e4 LT |
1435 | } |
1436 | ||
c627f9cc JS |
1437 | /** |
1438 | * zap_vma_ptes - remove ptes mapping the vma | |
1439 | * @vma: vm_area_struct holding ptes to be zapped | |
1440 | * @address: starting address of pages to zap | |
1441 | * @size: number of bytes to zap | |
1442 | * | |
1443 | * This function only unmaps ptes assigned to VM_PFNMAP vmas. | |
1444 | * | |
1445 | * The entire address range must be fully contained within the vma. | |
1446 | * | |
1447 | * Returns 0 if successful. | |
1448 | */ | |
1449 | int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, | |
1450 | unsigned long size) | |
1451 | { | |
1452 | if (address < vma->vm_start || address + size > vma->vm_end || | |
1453 | !(vma->vm_flags & VM_PFNMAP)) | |
1454 | return -1; | |
f5cc4eef | 1455 | zap_page_range_single(vma, address, size, NULL); |
c627f9cc JS |
1456 | return 0; |
1457 | } | |
1458 | EXPORT_SYMBOL_GPL(zap_vma_ptes); | |
1459 | ||
142762bd JW |
1460 | /** |
1461 | * follow_page - look up a page descriptor from a user-virtual address | |
1462 | * @vma: vm_area_struct mapping @address | |
1463 | * @address: virtual address to look up | |
1464 | * @flags: flags modifying lookup behaviour | |
1465 | * | |
1466 | * @flags can have FOLL_ flags set, defined in <linux/mm.h> | |
1467 | * | |
1468 | * Returns the mapped (struct page *), %NULL if no mapping exists, or | |
1469 | * an error pointer if there is a mapping to something not represented | |
1470 | * by a page descriptor (see also vm_normal_page()). | |
1da177e4 | 1471 | */ |
6aab341e | 1472 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1473 | unsigned int flags) |
1da177e4 LT |
1474 | { |
1475 | pgd_t *pgd; | |
1476 | pud_t *pud; | |
1477 | pmd_t *pmd; | |
1478 | pte_t *ptep, pte; | |
deceb6cd | 1479 | spinlock_t *ptl; |
1da177e4 | 1480 | struct page *page; |
6aab341e | 1481 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1482 | |
deceb6cd HD |
1483 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
1484 | if (!IS_ERR(page)) { | |
1485 | BUG_ON(flags & FOLL_GET); | |
1486 | goto out; | |
1487 | } | |
1da177e4 | 1488 | |
deceb6cd | 1489 | page = NULL; |
1da177e4 LT |
1490 | pgd = pgd_offset(mm, address); |
1491 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
deceb6cd | 1492 | goto no_page_table; |
1da177e4 LT |
1493 | |
1494 | pud = pud_offset(pgd, address); | |
ceb86879 | 1495 | if (pud_none(*pud)) |
deceb6cd | 1496 | goto no_page_table; |
8a07651e | 1497 | if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) { |
ceb86879 AK |
1498 | BUG_ON(flags & FOLL_GET); |
1499 | page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE); | |
1500 | goto out; | |
1501 | } | |
1502 | if (unlikely(pud_bad(*pud))) | |
1503 | goto no_page_table; | |
1504 | ||
1da177e4 | 1505 | pmd = pmd_offset(pud, address); |
aeed5fce | 1506 | if (pmd_none(*pmd)) |
deceb6cd | 1507 | goto no_page_table; |
71e3aac0 | 1508 | if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) { |
deceb6cd HD |
1509 | BUG_ON(flags & FOLL_GET); |
1510 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); | |
1da177e4 | 1511 | goto out; |
deceb6cd | 1512 | } |
0b9d7052 AA |
1513 | if ((flags & FOLL_NUMA) && pmd_numa(*pmd)) |
1514 | goto no_page_table; | |
71e3aac0 | 1515 | if (pmd_trans_huge(*pmd)) { |
500d65d4 | 1516 | if (flags & FOLL_SPLIT) { |
e180377f | 1517 | split_huge_page_pmd(vma, address, pmd); |
500d65d4 AA |
1518 | goto split_fallthrough; |
1519 | } | |
71e3aac0 AA |
1520 | spin_lock(&mm->page_table_lock); |
1521 | if (likely(pmd_trans_huge(*pmd))) { | |
1522 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
1523 | spin_unlock(&mm->page_table_lock); | |
1524 | wait_split_huge_page(vma->anon_vma, pmd); | |
1525 | } else { | |
b676b293 | 1526 | page = follow_trans_huge_pmd(vma, address, |
71e3aac0 AA |
1527 | pmd, flags); |
1528 | spin_unlock(&mm->page_table_lock); | |
1529 | goto out; | |
1530 | } | |
1531 | } else | |
1532 | spin_unlock(&mm->page_table_lock); | |
1533 | /* fall through */ | |
1534 | } | |
500d65d4 | 1535 | split_fallthrough: |
aeed5fce HD |
1536 | if (unlikely(pmd_bad(*pmd))) |
1537 | goto no_page_table; | |
1538 | ||
deceb6cd | 1539 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
1540 | |
1541 | pte = *ptep; | |
deceb6cd | 1542 | if (!pte_present(pte)) |
89f5b7da | 1543 | goto no_page; |
0b9d7052 AA |
1544 | if ((flags & FOLL_NUMA) && pte_numa(pte)) |
1545 | goto no_page; | |
deceb6cd HD |
1546 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
1547 | goto unlock; | |
a13ea5b7 | 1548 | |
6aab341e | 1549 | page = vm_normal_page(vma, address, pte); |
a13ea5b7 HD |
1550 | if (unlikely(!page)) { |
1551 | if ((flags & FOLL_DUMP) || | |
62eede62 | 1552 | !is_zero_pfn(pte_pfn(pte))) |
a13ea5b7 HD |
1553 | goto bad_page; |
1554 | page = pte_page(pte); | |
1555 | } | |
1da177e4 | 1556 | |
deceb6cd | 1557 | if (flags & FOLL_GET) |
70b50f94 | 1558 | get_page_foll(page); |
deceb6cd HD |
1559 | if (flags & FOLL_TOUCH) { |
1560 | if ((flags & FOLL_WRITE) && | |
1561 | !pte_dirty(pte) && !PageDirty(page)) | |
1562 | set_page_dirty(page); | |
bd775c42 KM |
1563 | /* |
1564 | * pte_mkyoung() would be more correct here, but atomic care | |
1565 | * is needed to avoid losing the dirty bit: it is easier to use | |
1566 | * mark_page_accessed(). | |
1567 | */ | |
deceb6cd HD |
1568 | mark_page_accessed(page); |
1569 | } | |
a1fde08c | 1570 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
110d74a9 ML |
1571 | /* |
1572 | * The preliminary mapping check is mainly to avoid the | |
1573 | * pointless overhead of lock_page on the ZERO_PAGE | |
1574 | * which might bounce very badly if there is contention. | |
1575 | * | |
1576 | * If the page is already locked, we don't need to | |
1577 | * handle it now - vmscan will handle it later if and | |
1578 | * when it attempts to reclaim the page. | |
1579 | */ | |
1580 | if (page->mapping && trylock_page(page)) { | |
1581 | lru_add_drain(); /* push cached pages to LRU */ | |
1582 | /* | |
e6c509f8 HD |
1583 | * Because we lock page here, and migration is |
1584 | * blocked by the pte's page reference, and we | |
1585 | * know the page is still mapped, we don't even | |
1586 | * need to check for file-cache page truncation. | |
110d74a9 | 1587 | */ |
e6c509f8 | 1588 | mlock_vma_page(page); |
110d74a9 ML |
1589 | unlock_page(page); |
1590 | } | |
1591 | } | |
deceb6cd HD |
1592 | unlock: |
1593 | pte_unmap_unlock(ptep, ptl); | |
1da177e4 | 1594 | out: |
deceb6cd | 1595 | return page; |
1da177e4 | 1596 | |
89f5b7da LT |
1597 | bad_page: |
1598 | pte_unmap_unlock(ptep, ptl); | |
1599 | return ERR_PTR(-EFAULT); | |
1600 | ||
1601 | no_page: | |
1602 | pte_unmap_unlock(ptep, ptl); | |
1603 | if (!pte_none(pte)) | |
1604 | return page; | |
8e4b9a60 | 1605 | |
deceb6cd HD |
1606 | no_page_table: |
1607 | /* | |
1608 | * When core dumping an enormous anonymous area that nobody | |
8e4b9a60 HD |
1609 | * has touched so far, we don't want to allocate unnecessary pages or |
1610 | * page tables. Return error instead of NULL to skip handle_mm_fault, | |
1611 | * then get_dump_page() will return NULL to leave a hole in the dump. | |
1612 | * But we can only make this optimization where a hole would surely | |
1613 | * be zero-filled if handle_mm_fault() actually did handle it. | |
deceb6cd | 1614 | */ |
8e4b9a60 HD |
1615 | if ((flags & FOLL_DUMP) && |
1616 | (!vma->vm_ops || !vma->vm_ops->fault)) | |
1617 | return ERR_PTR(-EFAULT); | |
deceb6cd | 1618 | return page; |
1da177e4 LT |
1619 | } |
1620 | ||
95042f9e LT |
1621 | static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr) |
1622 | { | |
a09a79f6 MP |
1623 | return stack_guard_page_start(vma, addr) || |
1624 | stack_guard_page_end(vma, addr+PAGE_SIZE); | |
95042f9e LT |
1625 | } |
1626 | ||
0014bd99 HY |
1627 | /** |
1628 | * __get_user_pages() - pin user pages in memory | |
1629 | * @tsk: task_struct of target task | |
1630 | * @mm: mm_struct of target mm | |
1631 | * @start: starting user address | |
1632 | * @nr_pages: number of pages from start to pin | |
1633 | * @gup_flags: flags modifying pin behaviour | |
1634 | * @pages: array that receives pointers to the pages pinned. | |
1635 | * Should be at least nr_pages long. Or NULL, if caller | |
1636 | * only intends to ensure the pages are faulted in. | |
1637 | * @vmas: array of pointers to vmas corresponding to each page. | |
1638 | * Or NULL if the caller does not require them. | |
1639 | * @nonblocking: whether waiting for disk IO or mmap_sem contention | |
1640 | * | |
1641 | * Returns number of pages pinned. This may be fewer than the number | |
1642 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
1643 | * were pinned, returns -errno. Each page returned must be released | |
1644 | * with a put_page() call when it is finished with. vmas will only | |
1645 | * remain valid while mmap_sem is held. | |
1646 | * | |
1647 | * Must be called with mmap_sem held for read or write. | |
1648 | * | |
1649 | * __get_user_pages walks a process's page tables and takes a reference to | |
1650 | * each struct page that each user address corresponds to at a given | |
1651 | * instant. That is, it takes the page that would be accessed if a user | |
1652 | * thread accesses the given user virtual address at that instant. | |
1653 | * | |
1654 | * This does not guarantee that the page exists in the user mappings when | |
1655 | * __get_user_pages returns, and there may even be a completely different | |
1656 | * page there in some cases (eg. if mmapped pagecache has been invalidated | |
1657 | * and subsequently re faulted). However it does guarantee that the page | |
1658 | * won't be freed completely. And mostly callers simply care that the page | |
1659 | * contains data that was valid *at some point in time*. Typically, an IO | |
1660 | * or similar operation cannot guarantee anything stronger anyway because | |
1661 | * locks can't be held over the syscall boundary. | |
1662 | * | |
1663 | * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If | |
1664 | * the page is written to, set_page_dirty (or set_page_dirty_lock, as | |
1665 | * appropriate) must be called after the page is finished with, and | |
1666 | * before put_page is called. | |
1667 | * | |
1668 | * If @nonblocking != NULL, __get_user_pages will not wait for disk IO | |
1669 | * or mmap_sem contention, and if waiting is needed to pin all pages, | |
1670 | * *@nonblocking will be set to 0. | |
1671 | * | |
1672 | * In most cases, get_user_pages or get_user_pages_fast should be used | |
1673 | * instead of __get_user_pages. __get_user_pages should be used only if | |
1674 | * you need some special @gup_flags. | |
1675 | */ | |
b291f000 | 1676 | int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
58fa879e | 1677 | unsigned long start, int nr_pages, unsigned int gup_flags, |
53a7706d ML |
1678 | struct page **pages, struct vm_area_struct **vmas, |
1679 | int *nonblocking) | |
1da177e4 LT |
1680 | { |
1681 | int i; | |
58fa879e | 1682 | unsigned long vm_flags; |
1da177e4 | 1683 | |
9d73777e | 1684 | if (nr_pages <= 0) |
900cf086 | 1685 | return 0; |
58fa879e HD |
1686 | |
1687 | VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); | |
1688 | ||
1da177e4 LT |
1689 | /* |
1690 | * Require read or write permissions. | |
58fa879e | 1691 | * If FOLL_FORCE is set, we only require the "MAY" flags. |
1da177e4 | 1692 | */ |
58fa879e HD |
1693 | vm_flags = (gup_flags & FOLL_WRITE) ? |
1694 | (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); | |
1695 | vm_flags &= (gup_flags & FOLL_FORCE) ? | |
1696 | (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
0b9d7052 AA |
1697 | |
1698 | /* | |
1699 | * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault | |
1700 | * would be called on PROT_NONE ranges. We must never invoke | |
1701 | * handle_mm_fault on PROT_NONE ranges or the NUMA hinting | |
1702 | * page faults would unprotect the PROT_NONE ranges if | |
1703 | * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd | |
1704 | * bitflag. So to avoid that, don't set FOLL_NUMA if | |
1705 | * FOLL_FORCE is set. | |
1706 | */ | |
1707 | if (!(gup_flags & FOLL_FORCE)) | |
1708 | gup_flags |= FOLL_NUMA; | |
1709 | ||
1da177e4 LT |
1710 | i = 0; |
1711 | ||
1712 | do { | |
deceb6cd | 1713 | struct vm_area_struct *vma; |
1da177e4 LT |
1714 | |
1715 | vma = find_extend_vma(mm, start); | |
e7f22e20 | 1716 | if (!vma && in_gate_area(mm, start)) { |
1da177e4 | 1717 | unsigned long pg = start & PAGE_MASK; |
1da177e4 LT |
1718 | pgd_t *pgd; |
1719 | pud_t *pud; | |
1720 | pmd_t *pmd; | |
1721 | pte_t *pte; | |
b291f000 NP |
1722 | |
1723 | /* user gate pages are read-only */ | |
58fa879e | 1724 | if (gup_flags & FOLL_WRITE) |
1da177e4 LT |
1725 | return i ? : -EFAULT; |
1726 | if (pg > TASK_SIZE) | |
1727 | pgd = pgd_offset_k(pg); | |
1728 | else | |
1729 | pgd = pgd_offset_gate(mm, pg); | |
1730 | BUG_ON(pgd_none(*pgd)); | |
1731 | pud = pud_offset(pgd, pg); | |
1732 | BUG_ON(pud_none(*pud)); | |
1733 | pmd = pmd_offset(pud, pg); | |
690dbe1c HD |
1734 | if (pmd_none(*pmd)) |
1735 | return i ? : -EFAULT; | |
f66055ab | 1736 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
1da177e4 | 1737 | pte = pte_offset_map(pmd, pg); |
690dbe1c HD |
1738 | if (pte_none(*pte)) { |
1739 | pte_unmap(pte); | |
1740 | return i ? : -EFAULT; | |
1741 | } | |
95042f9e | 1742 | vma = get_gate_vma(mm); |
1da177e4 | 1743 | if (pages) { |
de51257a HD |
1744 | struct page *page; |
1745 | ||
95042f9e | 1746 | page = vm_normal_page(vma, start, *pte); |
de51257a HD |
1747 | if (!page) { |
1748 | if (!(gup_flags & FOLL_DUMP) && | |
1749 | is_zero_pfn(pte_pfn(*pte))) | |
1750 | page = pte_page(*pte); | |
1751 | else { | |
1752 | pte_unmap(pte); | |
1753 | return i ? : -EFAULT; | |
1754 | } | |
1755 | } | |
6aab341e | 1756 | pages[i] = page; |
de51257a | 1757 | get_page(page); |
1da177e4 LT |
1758 | } |
1759 | pte_unmap(pte); | |
95042f9e | 1760 | goto next_page; |
1da177e4 LT |
1761 | } |
1762 | ||
b291f000 NP |
1763 | if (!vma || |
1764 | (vma->vm_flags & (VM_IO | VM_PFNMAP)) || | |
1c3aff1c | 1765 | !(vm_flags & vma->vm_flags)) |
1da177e4 LT |
1766 | return i ? : -EFAULT; |
1767 | ||
2a15efc9 HD |
1768 | if (is_vm_hugetlb_page(vma)) { |
1769 | i = follow_hugetlb_page(mm, vma, pages, vmas, | |
58fa879e | 1770 | &start, &nr_pages, i, gup_flags); |
2a15efc9 HD |
1771 | continue; |
1772 | } | |
deceb6cd | 1773 | |
1da177e4 | 1774 | do { |
08ef4729 | 1775 | struct page *page; |
58fa879e | 1776 | unsigned int foll_flags = gup_flags; |
1da177e4 | 1777 | |
462e00cc | 1778 | /* |
4779280d | 1779 | * If we have a pending SIGKILL, don't keep faulting |
1c3aff1c | 1780 | * pages and potentially allocating memory. |
462e00cc | 1781 | */ |
1c3aff1c | 1782 | if (unlikely(fatal_signal_pending(current))) |
4779280d | 1783 | return i ? i : -ERESTARTSYS; |
462e00cc | 1784 | |
deceb6cd | 1785 | cond_resched(); |
6aab341e | 1786 | while (!(page = follow_page(vma, start, foll_flags))) { |
deceb6cd | 1787 | int ret; |
53a7706d ML |
1788 | unsigned int fault_flags = 0; |
1789 | ||
a09a79f6 MP |
1790 | /* For mlock, just skip the stack guard page. */ |
1791 | if (foll_flags & FOLL_MLOCK) { | |
1792 | if (stack_guard_page(vma, start)) | |
1793 | goto next_page; | |
1794 | } | |
53a7706d ML |
1795 | if (foll_flags & FOLL_WRITE) |
1796 | fault_flags |= FAULT_FLAG_WRITE; | |
1797 | if (nonblocking) | |
1798 | fault_flags |= FAULT_FLAG_ALLOW_RETRY; | |
318b275f GN |
1799 | if (foll_flags & FOLL_NOWAIT) |
1800 | fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT); | |
d06063cc | 1801 | |
d26ed650 | 1802 | ret = handle_mm_fault(mm, vma, start, |
53a7706d | 1803 | fault_flags); |
d26ed650 | 1804 | |
83c54070 NP |
1805 | if (ret & VM_FAULT_ERROR) { |
1806 | if (ret & VM_FAULT_OOM) | |
1807 | return i ? i : -ENOMEM; | |
69ebb83e HY |
1808 | if (ret & (VM_FAULT_HWPOISON | |
1809 | VM_FAULT_HWPOISON_LARGE)) { | |
1810 | if (i) | |
1811 | return i; | |
1812 | else if (gup_flags & FOLL_HWPOISON) | |
1813 | return -EHWPOISON; | |
1814 | else | |
1815 | return -EFAULT; | |
1816 | } | |
1817 | if (ret & VM_FAULT_SIGBUS) | |
83c54070 NP |
1818 | return i ? i : -EFAULT; |
1819 | BUG(); | |
1820 | } | |
e7f22e20 SW |
1821 | |
1822 | if (tsk) { | |
1823 | if (ret & VM_FAULT_MAJOR) | |
1824 | tsk->maj_flt++; | |
1825 | else | |
1826 | tsk->min_flt++; | |
1827 | } | |
83c54070 | 1828 | |
53a7706d | 1829 | if (ret & VM_FAULT_RETRY) { |
318b275f GN |
1830 | if (nonblocking) |
1831 | *nonblocking = 0; | |
53a7706d ML |
1832 | return i; |
1833 | } | |
1834 | ||
a68d2ebc | 1835 | /* |
83c54070 NP |
1836 | * The VM_FAULT_WRITE bit tells us that |
1837 | * do_wp_page has broken COW when necessary, | |
1838 | * even if maybe_mkwrite decided not to set | |
1839 | * pte_write. We can thus safely do subsequent | |
878b63ac HD |
1840 | * page lookups as if they were reads. But only |
1841 | * do so when looping for pte_write is futile: | |
1842 | * in some cases userspace may also be wanting | |
1843 | * to write to the gotten user page, which a | |
1844 | * read fault here might prevent (a readonly | |
1845 | * page might get reCOWed by userspace write). | |
a68d2ebc | 1846 | */ |
878b63ac HD |
1847 | if ((ret & VM_FAULT_WRITE) && |
1848 | !(vma->vm_flags & VM_WRITE)) | |
deceb6cd | 1849 | foll_flags &= ~FOLL_WRITE; |
83c54070 | 1850 | |
7f7bbbe5 | 1851 | cond_resched(); |
1da177e4 | 1852 | } |
89f5b7da LT |
1853 | if (IS_ERR(page)) |
1854 | return i ? i : PTR_ERR(page); | |
1da177e4 | 1855 | if (pages) { |
08ef4729 | 1856 | pages[i] = page; |
03beb076 | 1857 | |
a6f36be3 | 1858 | flush_anon_page(vma, page, start); |
08ef4729 | 1859 | flush_dcache_page(page); |
1da177e4 | 1860 | } |
95042f9e | 1861 | next_page: |
1da177e4 LT |
1862 | if (vmas) |
1863 | vmas[i] = vma; | |
1864 | i++; | |
1865 | start += PAGE_SIZE; | |
9d73777e PZ |
1866 | nr_pages--; |
1867 | } while (nr_pages && start < vma->vm_end); | |
1868 | } while (nr_pages); | |
1da177e4 LT |
1869 | return i; |
1870 | } | |
0014bd99 | 1871 | EXPORT_SYMBOL(__get_user_pages); |
b291f000 | 1872 | |
2efaca92 BH |
1873 | /* |
1874 | * fixup_user_fault() - manually resolve a user page fault | |
1875 | * @tsk: the task_struct to use for page fault accounting, or | |
1876 | * NULL if faults are not to be recorded. | |
1877 | * @mm: mm_struct of target mm | |
1878 | * @address: user address | |
1879 | * @fault_flags:flags to pass down to handle_mm_fault() | |
1880 | * | |
1881 | * This is meant to be called in the specific scenario where for locking reasons | |
1882 | * we try to access user memory in atomic context (within a pagefault_disable() | |
1883 | * section), this returns -EFAULT, and we want to resolve the user fault before | |
1884 | * trying again. | |
1885 | * | |
1886 | * Typically this is meant to be used by the futex code. | |
1887 | * | |
1888 | * The main difference with get_user_pages() is that this function will | |
1889 | * unconditionally call handle_mm_fault() which will in turn perform all the | |
1890 | * necessary SW fixup of the dirty and young bits in the PTE, while | |
1891 | * handle_mm_fault() only guarantees to update these in the struct page. | |
1892 | * | |
1893 | * This is important for some architectures where those bits also gate the | |
1894 | * access permission to the page because they are maintained in software. On | |
1895 | * such architectures, gup() will not be enough to make a subsequent access | |
1896 | * succeed. | |
1897 | * | |
1898 | * This should be called with the mm_sem held for read. | |
1899 | */ | |
1900 | int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, | |
1901 | unsigned long address, unsigned int fault_flags) | |
1902 | { | |
1903 | struct vm_area_struct *vma; | |
1904 | int ret; | |
1905 | ||
1906 | vma = find_extend_vma(mm, address); | |
1907 | if (!vma || address < vma->vm_start) | |
1908 | return -EFAULT; | |
1909 | ||
1910 | ret = handle_mm_fault(mm, vma, address, fault_flags); | |
1911 | if (ret & VM_FAULT_ERROR) { | |
1912 | if (ret & VM_FAULT_OOM) | |
1913 | return -ENOMEM; | |
1914 | if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) | |
1915 | return -EHWPOISON; | |
1916 | if (ret & VM_FAULT_SIGBUS) | |
1917 | return -EFAULT; | |
1918 | BUG(); | |
1919 | } | |
1920 | if (tsk) { | |
1921 | if (ret & VM_FAULT_MAJOR) | |
1922 | tsk->maj_flt++; | |
1923 | else | |
1924 | tsk->min_flt++; | |
1925 | } | |
1926 | return 0; | |
1927 | } | |
1928 | ||
1929 | /* | |
d2bf6be8 | 1930 | * get_user_pages() - pin user pages in memory |
e7f22e20 SW |
1931 | * @tsk: the task_struct to use for page fault accounting, or |
1932 | * NULL if faults are not to be recorded. | |
d2bf6be8 NP |
1933 | * @mm: mm_struct of target mm |
1934 | * @start: starting user address | |
9d73777e | 1935 | * @nr_pages: number of pages from start to pin |
d2bf6be8 NP |
1936 | * @write: whether pages will be written to by the caller |
1937 | * @force: whether to force write access even if user mapping is | |
1938 | * readonly. This will result in the page being COWed even | |
1939 | * in MAP_SHARED mappings. You do not want this. | |
1940 | * @pages: array that receives pointers to the pages pinned. | |
1941 | * Should be at least nr_pages long. Or NULL, if caller | |
1942 | * only intends to ensure the pages are faulted in. | |
1943 | * @vmas: array of pointers to vmas corresponding to each page. | |
1944 | * Or NULL if the caller does not require them. | |
1945 | * | |
1946 | * Returns number of pages pinned. This may be fewer than the number | |
9d73777e | 1947 | * requested. If nr_pages is 0 or negative, returns 0. If no pages |
d2bf6be8 NP |
1948 | * were pinned, returns -errno. Each page returned must be released |
1949 | * with a put_page() call when it is finished with. vmas will only | |
1950 | * remain valid while mmap_sem is held. | |
1951 | * | |
1952 | * Must be called with mmap_sem held for read or write. | |
1953 | * | |
1954 | * get_user_pages walks a process's page tables and takes a reference to | |
1955 | * each struct page that each user address corresponds to at a given | |
1956 | * instant. That is, it takes the page that would be accessed if a user | |
1957 | * thread accesses the given user virtual address at that instant. | |
1958 | * | |
1959 | * This does not guarantee that the page exists in the user mappings when | |
1960 | * get_user_pages returns, and there may even be a completely different | |
1961 | * page there in some cases (eg. if mmapped pagecache has been invalidated | |
1962 | * and subsequently re faulted). However it does guarantee that the page | |
1963 | * won't be freed completely. And mostly callers simply care that the page | |
1964 | * contains data that was valid *at some point in time*. Typically, an IO | |
1965 | * or similar operation cannot guarantee anything stronger anyway because | |
1966 | * locks can't be held over the syscall boundary. | |
1967 | * | |
1968 | * If write=0, the page must not be written to. If the page is written to, | |
1969 | * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called | |
1970 | * after the page is finished with, and before put_page is called. | |
1971 | * | |
1972 | * get_user_pages is typically used for fewer-copy IO operations, to get a | |
1973 | * handle on the memory by some means other than accesses via the user virtual | |
1974 | * addresses. The pages may be submitted for DMA to devices or accessed via | |
1975 | * their kernel linear mapping (via the kmap APIs). Care should be taken to | |
1976 | * use the correct cache flushing APIs. | |
1977 | * | |
1978 | * See also get_user_pages_fast, for performance critical applications. | |
1979 | */ | |
b291f000 | 1980 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
9d73777e | 1981 | unsigned long start, int nr_pages, int write, int force, |
b291f000 NP |
1982 | struct page **pages, struct vm_area_struct **vmas) |
1983 | { | |
58fa879e | 1984 | int flags = FOLL_TOUCH; |
b291f000 | 1985 | |
58fa879e HD |
1986 | if (pages) |
1987 | flags |= FOLL_GET; | |
b291f000 | 1988 | if (write) |
58fa879e | 1989 | flags |= FOLL_WRITE; |
b291f000 | 1990 | if (force) |
58fa879e | 1991 | flags |= FOLL_FORCE; |
b291f000 | 1992 | |
53a7706d ML |
1993 | return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas, |
1994 | NULL); | |
b291f000 | 1995 | } |
1da177e4 LT |
1996 | EXPORT_SYMBOL(get_user_pages); |
1997 | ||
f3e8fccd HD |
1998 | /** |
1999 | * get_dump_page() - pin user page in memory while writing it to core dump | |
2000 | * @addr: user address | |
2001 | * | |
2002 | * Returns struct page pointer of user page pinned for dump, | |
2003 | * to be freed afterwards by page_cache_release() or put_page(). | |
2004 | * | |
2005 | * Returns NULL on any kind of failure - a hole must then be inserted into | |
2006 | * the corefile, to preserve alignment with its headers; and also returns | |
2007 | * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found - | |
2008 | * allowing a hole to be left in the corefile to save diskspace. | |
2009 | * | |
2010 | * Called without mmap_sem, but after all other threads have been killed. | |
2011 | */ | |
2012 | #ifdef CONFIG_ELF_CORE | |
2013 | struct page *get_dump_page(unsigned long addr) | |
2014 | { | |
2015 | struct vm_area_struct *vma; | |
2016 | struct page *page; | |
2017 | ||
2018 | if (__get_user_pages(current, current->mm, addr, 1, | |
53a7706d ML |
2019 | FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma, |
2020 | NULL) < 1) | |
f3e8fccd | 2021 | return NULL; |
f3e8fccd HD |
2022 | flush_cache_page(vma, addr, page_to_pfn(page)); |
2023 | return page; | |
2024 | } | |
2025 | #endif /* CONFIG_ELF_CORE */ | |
2026 | ||
25ca1d6c | 2027 | pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, |
920c7a5d | 2028 | spinlock_t **ptl) |
c9cfcddf LT |
2029 | { |
2030 | pgd_t * pgd = pgd_offset(mm, addr); | |
2031 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
2032 | if (pud) { | |
49c91fb0 | 2033 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
f66055ab AA |
2034 | if (pmd) { |
2035 | VM_BUG_ON(pmd_trans_huge(*pmd)); | |
c9cfcddf | 2036 | return pte_alloc_map_lock(mm, pmd, addr, ptl); |
f66055ab | 2037 | } |
c9cfcddf LT |
2038 | } |
2039 | return NULL; | |
2040 | } | |
2041 | ||
238f58d8 LT |
2042 | /* |
2043 | * This is the old fallback for page remapping. | |
2044 | * | |
2045 | * For historical reasons, it only allows reserved pages. Only | |
2046 | * old drivers should use this, and they needed to mark their | |
2047 | * pages reserved for the old functions anyway. | |
2048 | */ | |
423bad60 NP |
2049 | static int insert_page(struct vm_area_struct *vma, unsigned long addr, |
2050 | struct page *page, pgprot_t prot) | |
238f58d8 | 2051 | { |
423bad60 | 2052 | struct mm_struct *mm = vma->vm_mm; |
238f58d8 | 2053 | int retval; |
c9cfcddf | 2054 | pte_t *pte; |
8a9f3ccd BS |
2055 | spinlock_t *ptl; |
2056 | ||
238f58d8 | 2057 | retval = -EINVAL; |
a145dd41 | 2058 | if (PageAnon(page)) |
5b4e655e | 2059 | goto out; |
238f58d8 LT |
2060 | retval = -ENOMEM; |
2061 | flush_dcache_page(page); | |
c9cfcddf | 2062 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 | 2063 | if (!pte) |
5b4e655e | 2064 | goto out; |
238f58d8 LT |
2065 | retval = -EBUSY; |
2066 | if (!pte_none(*pte)) | |
2067 | goto out_unlock; | |
2068 | ||
2069 | /* Ok, finally just insert the thing.. */ | |
2070 | get_page(page); | |
34e55232 | 2071 | inc_mm_counter_fast(mm, MM_FILEPAGES); |
238f58d8 LT |
2072 | page_add_file_rmap(page); |
2073 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); | |
2074 | ||
2075 | retval = 0; | |
8a9f3ccd BS |
2076 | pte_unmap_unlock(pte, ptl); |
2077 | return retval; | |
238f58d8 LT |
2078 | out_unlock: |
2079 | pte_unmap_unlock(pte, ptl); | |
2080 | out: | |
2081 | return retval; | |
2082 | } | |
2083 | ||
bfa5bf6d REB |
2084 | /** |
2085 | * vm_insert_page - insert single page into user vma | |
2086 | * @vma: user vma to map to | |
2087 | * @addr: target user address of this page | |
2088 | * @page: source kernel page | |
2089 | * | |
a145dd41 LT |
2090 | * This allows drivers to insert individual pages they've allocated |
2091 | * into a user vma. | |
2092 | * | |
2093 | * The page has to be a nice clean _individual_ kernel allocation. | |
2094 | * If you allocate a compound page, you need to have marked it as | |
2095 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 2096 | * (see split_page()). |
a145dd41 LT |
2097 | * |
2098 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
2099 | * took an arbitrary page protection parameter. This doesn't allow | |
2100 | * that. Your vma protection will have to be set up correctly, which | |
2101 | * means that if you want a shared writable mapping, you'd better | |
2102 | * ask for a shared writable mapping! | |
2103 | * | |
2104 | * The page does not need to be reserved. | |
4b6e1e37 KK |
2105 | * |
2106 | * Usually this function is called from f_op->mmap() handler | |
2107 | * under mm->mmap_sem write-lock, so it can change vma->vm_flags. | |
2108 | * Caller must set VM_MIXEDMAP on vma if it wants to call this | |
2109 | * function from other places, for example from page-fault handler. | |
a145dd41 | 2110 | */ |
423bad60 NP |
2111 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
2112 | struct page *page) | |
a145dd41 LT |
2113 | { |
2114 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
2115 | return -EFAULT; | |
2116 | if (!page_count(page)) | |
2117 | return -EINVAL; | |
4b6e1e37 KK |
2118 | if (!(vma->vm_flags & VM_MIXEDMAP)) { |
2119 | BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem)); | |
2120 | BUG_ON(vma->vm_flags & VM_PFNMAP); | |
2121 | vma->vm_flags |= VM_MIXEDMAP; | |
2122 | } | |
423bad60 | 2123 | return insert_page(vma, addr, page, vma->vm_page_prot); |
a145dd41 | 2124 | } |
e3c3374f | 2125 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 2126 | |
423bad60 NP |
2127 | static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, |
2128 | unsigned long pfn, pgprot_t prot) | |
2129 | { | |
2130 | struct mm_struct *mm = vma->vm_mm; | |
2131 | int retval; | |
2132 | pte_t *pte, entry; | |
2133 | spinlock_t *ptl; | |
2134 | ||
2135 | retval = -ENOMEM; | |
2136 | pte = get_locked_pte(mm, addr, &ptl); | |
2137 | if (!pte) | |
2138 | goto out; | |
2139 | retval = -EBUSY; | |
2140 | if (!pte_none(*pte)) | |
2141 | goto out_unlock; | |
2142 | ||
2143 | /* Ok, finally just insert the thing.. */ | |
2144 | entry = pte_mkspecial(pfn_pte(pfn, prot)); | |
2145 | set_pte_at(mm, addr, pte, entry); | |
4b3073e1 | 2146 | update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ |
423bad60 NP |
2147 | |
2148 | retval = 0; | |
2149 | out_unlock: | |
2150 | pte_unmap_unlock(pte, ptl); | |
2151 | out: | |
2152 | return retval; | |
2153 | } | |
2154 | ||
e0dc0d8f NP |
2155 | /** |
2156 | * vm_insert_pfn - insert single pfn into user vma | |
2157 | * @vma: user vma to map to | |
2158 | * @addr: target user address of this page | |
2159 | * @pfn: source kernel pfn | |
2160 | * | |
c462f179 | 2161 | * Similar to vm_insert_page, this allows drivers to insert individual pages |
e0dc0d8f NP |
2162 | * they've allocated into a user vma. Same comments apply. |
2163 | * | |
2164 | * This function should only be called from a vm_ops->fault handler, and | |
2165 | * in that case the handler should return NULL. | |
0d71d10a NP |
2166 | * |
2167 | * vma cannot be a COW mapping. | |
2168 | * | |
2169 | * As this is called only for pages that do not currently exist, we | |
2170 | * do not need to flush old virtual caches or the TLB. | |
e0dc0d8f NP |
2171 | */ |
2172 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
423bad60 | 2173 | unsigned long pfn) |
e0dc0d8f | 2174 | { |
2ab64037 | 2175 | int ret; |
e4b866ed | 2176 | pgprot_t pgprot = vma->vm_page_prot; |
7e675137 NP |
2177 | /* |
2178 | * Technically, architectures with pte_special can avoid all these | |
2179 | * restrictions (same for remap_pfn_range). However we would like | |
2180 | * consistency in testing and feature parity among all, so we should | |
2181 | * try to keep these invariants in place for everybody. | |
2182 | */ | |
b379d790 JH |
2183 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); |
2184 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
2185 | (VM_PFNMAP|VM_MIXEDMAP)); | |
2186 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
2187 | BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); | |
e0dc0d8f | 2188 | |
423bad60 NP |
2189 | if (addr < vma->vm_start || addr >= vma->vm_end) |
2190 | return -EFAULT; | |
5180da41 | 2191 | if (track_pfn_insert(vma, &pgprot, pfn)) |
2ab64037 | 2192 | return -EINVAL; |
2193 | ||
e4b866ed | 2194 | ret = insert_pfn(vma, addr, pfn, pgprot); |
2ab64037 | 2195 | |
2ab64037 | 2196 | return ret; |
423bad60 NP |
2197 | } |
2198 | EXPORT_SYMBOL(vm_insert_pfn); | |
e0dc0d8f | 2199 | |
423bad60 NP |
2200 | int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, |
2201 | unsigned long pfn) | |
2202 | { | |
2203 | BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); | |
e0dc0d8f | 2204 | |
423bad60 NP |
2205 | if (addr < vma->vm_start || addr >= vma->vm_end) |
2206 | return -EFAULT; | |
e0dc0d8f | 2207 | |
423bad60 NP |
2208 | /* |
2209 | * If we don't have pte special, then we have to use the pfn_valid() | |
2210 | * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* | |
2211 | * refcount the page if pfn_valid is true (hence insert_page rather | |
62eede62 HD |
2212 | * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP |
2213 | * without pte special, it would there be refcounted as a normal page. | |
423bad60 NP |
2214 | */ |
2215 | if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) { | |
2216 | struct page *page; | |
2217 | ||
2218 | page = pfn_to_page(pfn); | |
2219 | return insert_page(vma, addr, page, vma->vm_page_prot); | |
2220 | } | |
2221 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
e0dc0d8f | 2222 | } |
423bad60 | 2223 | EXPORT_SYMBOL(vm_insert_mixed); |
e0dc0d8f | 2224 | |
1da177e4 LT |
2225 | /* |
2226 | * maps a range of physical memory into the requested pages. the old | |
2227 | * mappings are removed. any references to nonexistent pages results | |
2228 | * in null mappings (currently treated as "copy-on-access") | |
2229 | */ | |
2230 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
2231 | unsigned long addr, unsigned long end, | |
2232 | unsigned long pfn, pgprot_t prot) | |
2233 | { | |
2234 | pte_t *pte; | |
c74df32c | 2235 | spinlock_t *ptl; |
1da177e4 | 2236 | |
c74df32c | 2237 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
2238 | if (!pte) |
2239 | return -ENOMEM; | |
6606c3e0 | 2240 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
2241 | do { |
2242 | BUG_ON(!pte_none(*pte)); | |
7e675137 | 2243 | set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); |
1da177e4 LT |
2244 | pfn++; |
2245 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 2246 | arch_leave_lazy_mmu_mode(); |
c74df32c | 2247 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
2248 | return 0; |
2249 | } | |
2250 | ||
2251 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
2252 | unsigned long addr, unsigned long end, | |
2253 | unsigned long pfn, pgprot_t prot) | |
2254 | { | |
2255 | pmd_t *pmd; | |
2256 | unsigned long next; | |
2257 | ||
2258 | pfn -= addr >> PAGE_SHIFT; | |
2259 | pmd = pmd_alloc(mm, pud, addr); | |
2260 | if (!pmd) | |
2261 | return -ENOMEM; | |
f66055ab | 2262 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
1da177e4 LT |
2263 | do { |
2264 | next = pmd_addr_end(addr, end); | |
2265 | if (remap_pte_range(mm, pmd, addr, next, | |
2266 | pfn + (addr >> PAGE_SHIFT), prot)) | |
2267 | return -ENOMEM; | |
2268 | } while (pmd++, addr = next, addr != end); | |
2269 | return 0; | |
2270 | } | |
2271 | ||
2272 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
2273 | unsigned long addr, unsigned long end, | |
2274 | unsigned long pfn, pgprot_t prot) | |
2275 | { | |
2276 | pud_t *pud; | |
2277 | unsigned long next; | |
2278 | ||
2279 | pfn -= addr >> PAGE_SHIFT; | |
2280 | pud = pud_alloc(mm, pgd, addr); | |
2281 | if (!pud) | |
2282 | return -ENOMEM; | |
2283 | do { | |
2284 | next = pud_addr_end(addr, end); | |
2285 | if (remap_pmd_range(mm, pud, addr, next, | |
2286 | pfn + (addr >> PAGE_SHIFT), prot)) | |
2287 | return -ENOMEM; | |
2288 | } while (pud++, addr = next, addr != end); | |
2289 | return 0; | |
2290 | } | |
2291 | ||
bfa5bf6d REB |
2292 | /** |
2293 | * remap_pfn_range - remap kernel memory to userspace | |
2294 | * @vma: user vma to map to | |
2295 | * @addr: target user address to start at | |
2296 | * @pfn: physical address of kernel memory | |
2297 | * @size: size of map area | |
2298 | * @prot: page protection flags for this mapping | |
2299 | * | |
2300 | * Note: this is only safe if the mm semaphore is held when called. | |
2301 | */ | |
1da177e4 LT |
2302 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
2303 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
2304 | { | |
2305 | pgd_t *pgd; | |
2306 | unsigned long next; | |
2d15cab8 | 2307 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 LT |
2308 | struct mm_struct *mm = vma->vm_mm; |
2309 | int err; | |
2310 | ||
2311 | /* | |
2312 | * Physically remapped pages are special. Tell the | |
2313 | * rest of the world about it: | |
2314 | * VM_IO tells people not to look at these pages | |
2315 | * (accesses can have side effects). | |
6aab341e LT |
2316 | * VM_PFNMAP tells the core MM that the base pages are just |
2317 | * raw PFN mappings, and do not have a "struct page" associated | |
2318 | * with them. | |
314e51b9 KK |
2319 | * VM_DONTEXPAND |
2320 | * Disable vma merging and expanding with mremap(). | |
2321 | * VM_DONTDUMP | |
2322 | * Omit vma from core dump, even when VM_IO turned off. | |
fb155c16 LT |
2323 | * |
2324 | * There's a horrible special case to handle copy-on-write | |
2325 | * behaviour that some programs depend on. We mark the "original" | |
2326 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
b3b9c293 | 2327 | * See vm_normal_page() for details. |
1da177e4 | 2328 | */ |
b3b9c293 KK |
2329 | if (is_cow_mapping(vma->vm_flags)) { |
2330 | if (addr != vma->vm_start || end != vma->vm_end) | |
2331 | return -EINVAL; | |
fb155c16 | 2332 | vma->vm_pgoff = pfn; |
b3b9c293 KK |
2333 | } |
2334 | ||
2335 | err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size)); | |
2336 | if (err) | |
3c8bb73a | 2337 | return -EINVAL; |
fb155c16 | 2338 | |
314e51b9 | 2339 | vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; |
1da177e4 LT |
2340 | |
2341 | BUG_ON(addr >= end); | |
2342 | pfn -= addr >> PAGE_SHIFT; | |
2343 | pgd = pgd_offset(mm, addr); | |
2344 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
2345 | do { |
2346 | next = pgd_addr_end(addr, end); | |
2347 | err = remap_pud_range(mm, pgd, addr, next, | |
2348 | pfn + (addr >> PAGE_SHIFT), prot); | |
2349 | if (err) | |
2350 | break; | |
2351 | } while (pgd++, addr = next, addr != end); | |
2ab64037 | 2352 | |
2353 | if (err) | |
5180da41 | 2354 | untrack_pfn(vma, pfn, PAGE_ALIGN(size)); |
2ab64037 | 2355 | |
1da177e4 LT |
2356 | return err; |
2357 | } | |
2358 | EXPORT_SYMBOL(remap_pfn_range); | |
2359 | ||
aee16b3c JF |
2360 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
2361 | unsigned long addr, unsigned long end, | |
2362 | pte_fn_t fn, void *data) | |
2363 | { | |
2364 | pte_t *pte; | |
2365 | int err; | |
2f569afd | 2366 | pgtable_t token; |
94909914 | 2367 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
2368 | |
2369 | pte = (mm == &init_mm) ? | |
2370 | pte_alloc_kernel(pmd, addr) : | |
2371 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
2372 | if (!pte) | |
2373 | return -ENOMEM; | |
2374 | ||
2375 | BUG_ON(pmd_huge(*pmd)); | |
2376 | ||
38e0edb1 JF |
2377 | arch_enter_lazy_mmu_mode(); |
2378 | ||
2f569afd | 2379 | token = pmd_pgtable(*pmd); |
aee16b3c JF |
2380 | |
2381 | do { | |
c36987e2 | 2382 | err = fn(pte++, token, addr, data); |
aee16b3c JF |
2383 | if (err) |
2384 | break; | |
c36987e2 | 2385 | } while (addr += PAGE_SIZE, addr != end); |
aee16b3c | 2386 | |
38e0edb1 JF |
2387 | arch_leave_lazy_mmu_mode(); |
2388 | ||
aee16b3c JF |
2389 | if (mm != &init_mm) |
2390 | pte_unmap_unlock(pte-1, ptl); | |
2391 | return err; | |
2392 | } | |
2393 | ||
2394 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
2395 | unsigned long addr, unsigned long end, | |
2396 | pte_fn_t fn, void *data) | |
2397 | { | |
2398 | pmd_t *pmd; | |
2399 | unsigned long next; | |
2400 | int err; | |
2401 | ||
ceb86879 AK |
2402 | BUG_ON(pud_huge(*pud)); |
2403 | ||
aee16b3c JF |
2404 | pmd = pmd_alloc(mm, pud, addr); |
2405 | if (!pmd) | |
2406 | return -ENOMEM; | |
2407 | do { | |
2408 | next = pmd_addr_end(addr, end); | |
2409 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
2410 | if (err) | |
2411 | break; | |
2412 | } while (pmd++, addr = next, addr != end); | |
2413 | return err; | |
2414 | } | |
2415 | ||
2416 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
2417 | unsigned long addr, unsigned long end, | |
2418 | pte_fn_t fn, void *data) | |
2419 | { | |
2420 | pud_t *pud; | |
2421 | unsigned long next; | |
2422 | int err; | |
2423 | ||
2424 | pud = pud_alloc(mm, pgd, addr); | |
2425 | if (!pud) | |
2426 | return -ENOMEM; | |
2427 | do { | |
2428 | next = pud_addr_end(addr, end); | |
2429 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
2430 | if (err) | |
2431 | break; | |
2432 | } while (pud++, addr = next, addr != end); | |
2433 | return err; | |
2434 | } | |
2435 | ||
2436 | /* | |
2437 | * Scan a region of virtual memory, filling in page tables as necessary | |
2438 | * and calling a provided function on each leaf page table. | |
2439 | */ | |
2440 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
2441 | unsigned long size, pte_fn_t fn, void *data) | |
2442 | { | |
2443 | pgd_t *pgd; | |
2444 | unsigned long next; | |
57250a5b | 2445 | unsigned long end = addr + size; |
aee16b3c JF |
2446 | int err; |
2447 | ||
2448 | BUG_ON(addr >= end); | |
2449 | pgd = pgd_offset(mm, addr); | |
2450 | do { | |
2451 | next = pgd_addr_end(addr, end); | |
2452 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
2453 | if (err) | |
2454 | break; | |
2455 | } while (pgd++, addr = next, addr != end); | |
57250a5b | 2456 | |
aee16b3c JF |
2457 | return err; |
2458 | } | |
2459 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
2460 | ||
8f4e2101 HD |
2461 | /* |
2462 | * handle_pte_fault chooses page fault handler according to an entry | |
2463 | * which was read non-atomically. Before making any commitment, on | |
2464 | * those architectures or configurations (e.g. i386 with PAE) which | |
a335b2e1 | 2465 | * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault |
8f4e2101 HD |
2466 | * must check under lock before unmapping the pte and proceeding |
2467 | * (but do_wp_page is only called after already making such a check; | |
a335b2e1 | 2468 | * and do_anonymous_page can safely check later on). |
8f4e2101 | 2469 | */ |
4c21e2f2 | 2470 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
2471 | pte_t *page_table, pte_t orig_pte) |
2472 | { | |
2473 | int same = 1; | |
2474 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
2475 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
2476 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
2477 | spin_lock(ptl); | |
8f4e2101 | 2478 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 2479 | spin_unlock(ptl); |
8f4e2101 HD |
2480 | } |
2481 | #endif | |
2482 | pte_unmap(page_table); | |
2483 | return same; | |
2484 | } | |
2485 | ||
9de455b2 | 2486 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e LT |
2487 | { |
2488 | /* | |
2489 | * If the source page was a PFN mapping, we don't have | |
2490 | * a "struct page" for it. We do a best-effort copy by | |
2491 | * just copying from the original user address. If that | |
2492 | * fails, we just zero-fill it. Live with it. | |
2493 | */ | |
2494 | if (unlikely(!src)) { | |
9b04c5fe | 2495 | void *kaddr = kmap_atomic(dst); |
5d2a2dbb LT |
2496 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
2497 | ||
2498 | /* | |
2499 | * This really shouldn't fail, because the page is there | |
2500 | * in the page tables. But it might just be unreadable, | |
2501 | * in which case we just give up and fill the result with | |
2502 | * zeroes. | |
2503 | */ | |
2504 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
3ecb01df | 2505 | clear_page(kaddr); |
9b04c5fe | 2506 | kunmap_atomic(kaddr); |
c4ec7b0d | 2507 | flush_dcache_page(dst); |
0ed361de NP |
2508 | } else |
2509 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
2510 | } |
2511 | ||
1da177e4 LT |
2512 | /* |
2513 | * This routine handles present pages, when users try to write | |
2514 | * to a shared page. It is done by copying the page to a new address | |
2515 | * and decrementing the shared-page counter for the old page. | |
2516 | * | |
1da177e4 LT |
2517 | * Note that this routine assumes that the protection checks have been |
2518 | * done by the caller (the low-level page fault routine in most cases). | |
2519 | * Thus we can safely just mark it writable once we've done any necessary | |
2520 | * COW. | |
2521 | * | |
2522 | * We also mark the page dirty at this point even though the page will | |
2523 | * change only once the write actually happens. This avoids a few races, | |
2524 | * and potentially makes it more efficient. | |
2525 | * | |
8f4e2101 HD |
2526 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2527 | * but allow concurrent faults), with pte both mapped and locked. | |
2528 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2529 | */ |
65500d23 HD |
2530 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2531 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
8f4e2101 | 2532 | spinlock_t *ptl, pte_t orig_pte) |
e6219ec8 | 2533 | __releases(ptl) |
1da177e4 | 2534 | { |
2ec74c3e | 2535 | struct page *old_page, *new_page = NULL; |
1da177e4 | 2536 | pte_t entry; |
b009c024 | 2537 | int ret = 0; |
a200ee18 | 2538 | int page_mkwrite = 0; |
d08b3851 | 2539 | struct page *dirty_page = NULL; |
1756954c DR |
2540 | unsigned long mmun_start = 0; /* For mmu_notifiers */ |
2541 | unsigned long mmun_end = 0; /* For mmu_notifiers */ | |
1da177e4 | 2542 | |
6aab341e | 2543 | old_page = vm_normal_page(vma, address, orig_pte); |
251b97f5 PZ |
2544 | if (!old_page) { |
2545 | /* | |
2546 | * VM_MIXEDMAP !pfn_valid() case | |
2547 | * | |
2548 | * We should not cow pages in a shared writeable mapping. | |
2549 | * Just mark the pages writable as we can't do any dirty | |
2550 | * accounting on raw pfn maps. | |
2551 | */ | |
2552 | if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
2553 | (VM_WRITE|VM_SHARED)) | |
2554 | goto reuse; | |
6aab341e | 2555 | goto gotten; |
251b97f5 | 2556 | } |
1da177e4 | 2557 | |
d08b3851 | 2558 | /* |
ee6a6457 PZ |
2559 | * Take out anonymous pages first, anonymous shared vmas are |
2560 | * not dirty accountable. | |
d08b3851 | 2561 | */ |
9a840895 | 2562 | if (PageAnon(old_page) && !PageKsm(old_page)) { |
ab967d86 HD |
2563 | if (!trylock_page(old_page)) { |
2564 | page_cache_get(old_page); | |
2565 | pte_unmap_unlock(page_table, ptl); | |
2566 | lock_page(old_page); | |
2567 | page_table = pte_offset_map_lock(mm, pmd, address, | |
2568 | &ptl); | |
2569 | if (!pte_same(*page_table, orig_pte)) { | |
2570 | unlock_page(old_page); | |
ab967d86 HD |
2571 | goto unlock; |
2572 | } | |
2573 | page_cache_release(old_page); | |
ee6a6457 | 2574 | } |
b009c024 | 2575 | if (reuse_swap_page(old_page)) { |
c44b6743 RR |
2576 | /* |
2577 | * The page is all ours. Move it to our anon_vma so | |
2578 | * the rmap code will not search our parent or siblings. | |
2579 | * Protected against the rmap code by the page lock. | |
2580 | */ | |
2581 | page_move_anon_rmap(old_page, vma, address); | |
b009c024 ML |
2582 | unlock_page(old_page); |
2583 | goto reuse; | |
2584 | } | |
ab967d86 | 2585 | unlock_page(old_page); |
ee6a6457 | 2586 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == |
d08b3851 | 2587 | (VM_WRITE|VM_SHARED))) { |
ee6a6457 PZ |
2588 | /* |
2589 | * Only catch write-faults on shared writable pages, | |
2590 | * read-only shared pages can get COWed by | |
2591 | * get_user_pages(.write=1, .force=1). | |
2592 | */ | |
9637a5ef | 2593 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
c2ec175c NP |
2594 | struct vm_fault vmf; |
2595 | int tmp; | |
2596 | ||
2597 | vmf.virtual_address = (void __user *)(address & | |
2598 | PAGE_MASK); | |
2599 | vmf.pgoff = old_page->index; | |
2600 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; | |
2601 | vmf.page = old_page; | |
2602 | ||
9637a5ef DH |
2603 | /* |
2604 | * Notify the address space that the page is about to | |
2605 | * become writable so that it can prohibit this or wait | |
2606 | * for the page to get into an appropriate state. | |
2607 | * | |
2608 | * We do this without the lock held, so that it can | |
2609 | * sleep if it needs to. | |
2610 | */ | |
2611 | page_cache_get(old_page); | |
2612 | pte_unmap_unlock(page_table, ptl); | |
2613 | ||
c2ec175c NP |
2614 | tmp = vma->vm_ops->page_mkwrite(vma, &vmf); |
2615 | if (unlikely(tmp & | |
2616 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { | |
2617 | ret = tmp; | |
9637a5ef | 2618 | goto unwritable_page; |
c2ec175c | 2619 | } |
b827e496 NP |
2620 | if (unlikely(!(tmp & VM_FAULT_LOCKED))) { |
2621 | lock_page(old_page); | |
2622 | if (!old_page->mapping) { | |
2623 | ret = 0; /* retry the fault */ | |
2624 | unlock_page(old_page); | |
2625 | goto unwritable_page; | |
2626 | } | |
2627 | } else | |
2628 | VM_BUG_ON(!PageLocked(old_page)); | |
9637a5ef | 2629 | |
9637a5ef DH |
2630 | /* |
2631 | * Since we dropped the lock we need to revalidate | |
2632 | * the PTE as someone else may have changed it. If | |
2633 | * they did, we just return, as we can count on the | |
2634 | * MMU to tell us if they didn't also make it writable. | |
2635 | */ | |
2636 | page_table = pte_offset_map_lock(mm, pmd, address, | |
2637 | &ptl); | |
b827e496 NP |
2638 | if (!pte_same(*page_table, orig_pte)) { |
2639 | unlock_page(old_page); | |
9637a5ef | 2640 | goto unlock; |
b827e496 | 2641 | } |
a200ee18 PZ |
2642 | |
2643 | page_mkwrite = 1; | |
1da177e4 | 2644 | } |
d08b3851 PZ |
2645 | dirty_page = old_page; |
2646 | get_page(dirty_page); | |
9637a5ef | 2647 | |
251b97f5 | 2648 | reuse: |
9637a5ef DH |
2649 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
2650 | entry = pte_mkyoung(orig_pte); | |
2651 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
954ffcb3 | 2652 | if (ptep_set_access_flags(vma, address, page_table, entry,1)) |
4b3073e1 | 2653 | update_mmu_cache(vma, address, page_table); |
72ddc8f7 | 2654 | pte_unmap_unlock(page_table, ptl); |
9637a5ef | 2655 | ret |= VM_FAULT_WRITE; |
72ddc8f7 ML |
2656 | |
2657 | if (!dirty_page) | |
2658 | return ret; | |
2659 | ||
2660 | /* | |
2661 | * Yes, Virginia, this is actually required to prevent a race | |
2662 | * with clear_page_dirty_for_io() from clearing the page dirty | |
2663 | * bit after it clear all dirty ptes, but before a racing | |
2664 | * do_wp_page installs a dirty pte. | |
2665 | * | |
a335b2e1 | 2666 | * __do_fault is protected similarly. |
72ddc8f7 ML |
2667 | */ |
2668 | if (!page_mkwrite) { | |
2669 | wait_on_page_locked(dirty_page); | |
2670 | set_page_dirty_balance(dirty_page, page_mkwrite); | |
41c4d25f JK |
2671 | /* file_update_time outside page_lock */ |
2672 | if (vma->vm_file) | |
2673 | file_update_time(vma->vm_file); | |
72ddc8f7 ML |
2674 | } |
2675 | put_page(dirty_page); | |
2676 | if (page_mkwrite) { | |
2677 | struct address_space *mapping = dirty_page->mapping; | |
2678 | ||
2679 | set_page_dirty(dirty_page); | |
2680 | unlock_page(dirty_page); | |
2681 | page_cache_release(dirty_page); | |
2682 | if (mapping) { | |
2683 | /* | |
2684 | * Some device drivers do not set page.mapping | |
2685 | * but still dirty their pages | |
2686 | */ | |
2687 | balance_dirty_pages_ratelimited(mapping); | |
2688 | } | |
2689 | } | |
2690 | ||
72ddc8f7 | 2691 | return ret; |
1da177e4 | 2692 | } |
1da177e4 LT |
2693 | |
2694 | /* | |
2695 | * Ok, we need to copy. Oh, well.. | |
2696 | */ | |
b5810039 | 2697 | page_cache_get(old_page); |
920fc356 | 2698 | gotten: |
8f4e2101 | 2699 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2700 | |
2701 | if (unlikely(anon_vma_prepare(vma))) | |
65500d23 | 2702 | goto oom; |
a13ea5b7 | 2703 | |
62eede62 | 2704 | if (is_zero_pfn(pte_pfn(orig_pte))) { |
a13ea5b7 HD |
2705 | new_page = alloc_zeroed_user_highpage_movable(vma, address); |
2706 | if (!new_page) | |
2707 | goto oom; | |
2708 | } else { | |
2709 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
2710 | if (!new_page) | |
2711 | goto oom; | |
2712 | cow_user_page(new_page, old_page, address, vma); | |
2713 | } | |
2714 | __SetPageUptodate(new_page); | |
2715 | ||
2c26fdd7 | 2716 | if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
2717 | goto oom_free_new; |
2718 | ||
6bdb913f | 2719 | mmun_start = address & PAGE_MASK; |
1756954c | 2720 | mmun_end = mmun_start + PAGE_SIZE; |
6bdb913f HE |
2721 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2722 | ||
1da177e4 LT |
2723 | /* |
2724 | * Re-check the pte - we dropped the lock | |
2725 | */ | |
8f4e2101 | 2726 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
65500d23 | 2727 | if (likely(pte_same(*page_table, orig_pte))) { |
920fc356 | 2728 | if (old_page) { |
920fc356 | 2729 | if (!PageAnon(old_page)) { |
34e55232 KH |
2730 | dec_mm_counter_fast(mm, MM_FILEPAGES); |
2731 | inc_mm_counter_fast(mm, MM_ANONPAGES); | |
920fc356 HD |
2732 | } |
2733 | } else | |
34e55232 | 2734 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
eca35133 | 2735 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
65500d23 HD |
2736 | entry = mk_pte(new_page, vma->vm_page_prot); |
2737 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
4ce072f1 SS |
2738 | /* |
2739 | * Clear the pte entry and flush it first, before updating the | |
2740 | * pte with the new entry. This will avoid a race condition | |
2741 | * seen in the presence of one thread doing SMC and another | |
2742 | * thread doing COW. | |
2743 | */ | |
828502d3 | 2744 | ptep_clear_flush(vma, address, page_table); |
9617d95e | 2745 | page_add_new_anon_rmap(new_page, vma, address); |
828502d3 IE |
2746 | /* |
2747 | * We call the notify macro here because, when using secondary | |
2748 | * mmu page tables (such as kvm shadow page tables), we want the | |
2749 | * new page to be mapped directly into the secondary page table. | |
2750 | */ | |
2751 | set_pte_at_notify(mm, address, page_table, entry); | |
4b3073e1 | 2752 | update_mmu_cache(vma, address, page_table); |
945754a1 NP |
2753 | if (old_page) { |
2754 | /* | |
2755 | * Only after switching the pte to the new page may | |
2756 | * we remove the mapcount here. Otherwise another | |
2757 | * process may come and find the rmap count decremented | |
2758 | * before the pte is switched to the new page, and | |
2759 | * "reuse" the old page writing into it while our pte | |
2760 | * here still points into it and can be read by other | |
2761 | * threads. | |
2762 | * | |
2763 | * The critical issue is to order this | |
2764 | * page_remove_rmap with the ptp_clear_flush above. | |
2765 | * Those stores are ordered by (if nothing else,) | |
2766 | * the barrier present in the atomic_add_negative | |
2767 | * in page_remove_rmap. | |
2768 | * | |
2769 | * Then the TLB flush in ptep_clear_flush ensures that | |
2770 | * no process can access the old page before the | |
2771 | * decremented mapcount is visible. And the old page | |
2772 | * cannot be reused until after the decremented | |
2773 | * mapcount is visible. So transitively, TLBs to | |
2774 | * old page will be flushed before it can be reused. | |
2775 | */ | |
edc315fd | 2776 | page_remove_rmap(old_page); |
945754a1 NP |
2777 | } |
2778 | ||
1da177e4 LT |
2779 | /* Free the old page.. */ |
2780 | new_page = old_page; | |
f33ea7f4 | 2781 | ret |= VM_FAULT_WRITE; |
8a9f3ccd BS |
2782 | } else |
2783 | mem_cgroup_uncharge_page(new_page); | |
2784 | ||
6bdb913f HE |
2785 | if (new_page) |
2786 | page_cache_release(new_page); | |
65500d23 | 2787 | unlock: |
8f4e2101 | 2788 | pte_unmap_unlock(page_table, ptl); |
1756954c | 2789 | if (mmun_end > mmun_start) |
6bdb913f | 2790 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
e15f8c01 ML |
2791 | if (old_page) { |
2792 | /* | |
2793 | * Don't let another task, with possibly unlocked vma, | |
2794 | * keep the mlocked page. | |
2795 | */ | |
2796 | if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) { | |
2797 | lock_page(old_page); /* LRU manipulation */ | |
2798 | munlock_vma_page(old_page); | |
2799 | unlock_page(old_page); | |
2800 | } | |
2801 | page_cache_release(old_page); | |
2802 | } | |
f33ea7f4 | 2803 | return ret; |
8a9f3ccd | 2804 | oom_free_new: |
6dbf6d3b | 2805 | page_cache_release(new_page); |
65500d23 | 2806 | oom: |
66521d5a | 2807 | if (old_page) |
920fc356 | 2808 | page_cache_release(old_page); |
1da177e4 | 2809 | return VM_FAULT_OOM; |
9637a5ef DH |
2810 | |
2811 | unwritable_page: | |
2812 | page_cache_release(old_page); | |
c2ec175c | 2813 | return ret; |
1da177e4 LT |
2814 | } |
2815 | ||
97a89413 | 2816 | static void unmap_mapping_range_vma(struct vm_area_struct *vma, |
1da177e4 LT |
2817 | unsigned long start_addr, unsigned long end_addr, |
2818 | struct zap_details *details) | |
2819 | { | |
f5cc4eef | 2820 | zap_page_range_single(vma, start_addr, end_addr - start_addr, details); |
1da177e4 LT |
2821 | } |
2822 | ||
6b2dbba8 | 2823 | static inline void unmap_mapping_range_tree(struct rb_root *root, |
1da177e4 LT |
2824 | struct zap_details *details) |
2825 | { | |
2826 | struct vm_area_struct *vma; | |
1da177e4 LT |
2827 | pgoff_t vba, vea, zba, zea; |
2828 | ||
6b2dbba8 | 2829 | vma_interval_tree_foreach(vma, root, |
1da177e4 | 2830 | details->first_index, details->last_index) { |
1da177e4 LT |
2831 | |
2832 | vba = vma->vm_pgoff; | |
2833 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; | |
2834 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ | |
2835 | zba = details->first_index; | |
2836 | if (zba < vba) | |
2837 | zba = vba; | |
2838 | zea = details->last_index; | |
2839 | if (zea > vea) | |
2840 | zea = vea; | |
2841 | ||
97a89413 | 2842 | unmap_mapping_range_vma(vma, |
1da177e4 LT |
2843 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, |
2844 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
97a89413 | 2845 | details); |
1da177e4 LT |
2846 | } |
2847 | } | |
2848 | ||
2849 | static inline void unmap_mapping_range_list(struct list_head *head, | |
2850 | struct zap_details *details) | |
2851 | { | |
2852 | struct vm_area_struct *vma; | |
2853 | ||
2854 | /* | |
2855 | * In nonlinear VMAs there is no correspondence between virtual address | |
2856 | * offset and file offset. So we must perform an exhaustive search | |
2857 | * across *all* the pages in each nonlinear VMA, not just the pages | |
2858 | * whose virtual address lies outside the file truncation point. | |
2859 | */ | |
6b2dbba8 | 2860 | list_for_each_entry(vma, head, shared.nonlinear) { |
1da177e4 | 2861 | details->nonlinear_vma = vma; |
97a89413 | 2862 | unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details); |
1da177e4 LT |
2863 | } |
2864 | } | |
2865 | ||
2866 | /** | |
72fd4a35 | 2867 | * 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 | 2868 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
2869 | * @holebegin: byte in first page to unmap, relative to the start of |
2870 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
25d9e2d1 | 2871 | * boundary. Note that this is different from truncate_pagecache(), which |
1da177e4 LT |
2872 | * must keep the partial page. In contrast, we must get rid of |
2873 | * partial pages. | |
2874 | * @holelen: size of prospective hole in bytes. This will be rounded | |
2875 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
2876 | * end of the file. | |
2877 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
2878 | * but 0 when invalidating pagecache, don't throw away private data. | |
2879 | */ | |
2880 | void unmap_mapping_range(struct address_space *mapping, | |
2881 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
2882 | { | |
2883 | struct zap_details details; | |
2884 | pgoff_t hba = holebegin >> PAGE_SHIFT; | |
2885 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2886 | ||
2887 | /* Check for overflow. */ | |
2888 | if (sizeof(holelen) > sizeof(hlen)) { | |
2889 | long long holeend = | |
2890 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2891 | if (holeend & ~(long long)ULONG_MAX) | |
2892 | hlen = ULONG_MAX - hba + 1; | |
2893 | } | |
2894 | ||
2895 | details.check_mapping = even_cows? NULL: mapping; | |
2896 | details.nonlinear_vma = NULL; | |
2897 | details.first_index = hba; | |
2898 | details.last_index = hba + hlen - 1; | |
2899 | if (details.last_index < details.first_index) | |
2900 | details.last_index = ULONG_MAX; | |
1da177e4 | 2901 | |
1da177e4 | 2902 | |
3d48ae45 | 2903 | mutex_lock(&mapping->i_mmap_mutex); |
6b2dbba8 | 2904 | if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap))) |
1da177e4 LT |
2905 | unmap_mapping_range_tree(&mapping->i_mmap, &details); |
2906 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) | |
2907 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); | |
3d48ae45 | 2908 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
2909 | } |
2910 | EXPORT_SYMBOL(unmap_mapping_range); | |
2911 | ||
1da177e4 | 2912 | /* |
8f4e2101 HD |
2913 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2914 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2915 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2916 | */ |
65500d23 HD |
2917 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2918 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 2919 | unsigned int flags, pte_t orig_pte) |
1da177e4 | 2920 | { |
8f4e2101 | 2921 | spinlock_t *ptl; |
4969c119 | 2922 | struct page *page, *swapcache = NULL; |
65500d23 | 2923 | swp_entry_t entry; |
1da177e4 | 2924 | pte_t pte; |
d065bd81 | 2925 | int locked; |
56039efa | 2926 | struct mem_cgroup *ptr; |
ad8c2ee8 | 2927 | int exclusive = 0; |
83c54070 | 2928 | int ret = 0; |
1da177e4 | 2929 | |
4c21e2f2 | 2930 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
8f4e2101 | 2931 | goto out; |
65500d23 HD |
2932 | |
2933 | entry = pte_to_swp_entry(orig_pte); | |
d1737fdb AK |
2934 | if (unlikely(non_swap_entry(entry))) { |
2935 | if (is_migration_entry(entry)) { | |
2936 | migration_entry_wait(mm, pmd, address); | |
2937 | } else if (is_hwpoison_entry(entry)) { | |
2938 | ret = VM_FAULT_HWPOISON; | |
2939 | } else { | |
2940 | print_bad_pte(vma, address, orig_pte, NULL); | |
d99be1a8 | 2941 | ret = VM_FAULT_SIGBUS; |
d1737fdb | 2942 | } |
0697212a CL |
2943 | goto out; |
2944 | } | |
0ff92245 | 2945 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2946 | page = lookup_swap_cache(entry); |
2947 | if (!page) { | |
02098fea HD |
2948 | page = swapin_readahead(entry, |
2949 | GFP_HIGHUSER_MOVABLE, vma, address); | |
1da177e4 LT |
2950 | if (!page) { |
2951 | /* | |
8f4e2101 HD |
2952 | * Back out if somebody else faulted in this pte |
2953 | * while we released the pte lock. | |
1da177e4 | 2954 | */ |
8f4e2101 | 2955 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2956 | if (likely(pte_same(*page_table, orig_pte))) |
2957 | ret = VM_FAULT_OOM; | |
0ff92245 | 2958 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2959 | goto unlock; |
1da177e4 LT |
2960 | } |
2961 | ||
2962 | /* Had to read the page from swap area: Major fault */ | |
2963 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2964 | count_vm_event(PGMAJFAULT); |
456f998e | 2965 | mem_cgroup_count_vm_event(mm, PGMAJFAULT); |
d1737fdb | 2966 | } else if (PageHWPoison(page)) { |
71f72525 WF |
2967 | /* |
2968 | * hwpoisoned dirty swapcache pages are kept for killing | |
2969 | * owner processes (which may be unknown at hwpoison time) | |
2970 | */ | |
d1737fdb AK |
2971 | ret = VM_FAULT_HWPOISON; |
2972 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); | |
4779cb31 | 2973 | goto out_release; |
1da177e4 LT |
2974 | } |
2975 | ||
d065bd81 | 2976 | locked = lock_page_or_retry(page, mm, flags); |
e709ffd6 | 2977 | |
073e587e | 2978 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
d065bd81 ML |
2979 | if (!locked) { |
2980 | ret |= VM_FAULT_RETRY; | |
2981 | goto out_release; | |
2982 | } | |
073e587e | 2983 | |
4969c119 | 2984 | /* |
31c4a3d3 HD |
2985 | * Make sure try_to_free_swap or reuse_swap_page or swapoff did not |
2986 | * release the swapcache from under us. The page pin, and pte_same | |
2987 | * test below, are not enough to exclude that. Even if it is still | |
2988 | * swapcache, we need to check that the page's swap has not changed. | |
4969c119 | 2989 | */ |
31c4a3d3 | 2990 | if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val)) |
4969c119 AA |
2991 | goto out_page; |
2992 | ||
2993 | if (ksm_might_need_to_copy(page, vma, address)) { | |
2994 | swapcache = page; | |
2995 | page = ksm_does_need_to_copy(page, vma, address); | |
2996 | ||
2997 | if (unlikely(!page)) { | |
2998 | ret = VM_FAULT_OOM; | |
2999 | page = swapcache; | |
3000 | swapcache = NULL; | |
3001 | goto out_page; | |
3002 | } | |
5ad64688 HD |
3003 | } |
3004 | ||
2c26fdd7 | 3005 | if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) { |
8a9f3ccd | 3006 | ret = VM_FAULT_OOM; |
bc43f75c | 3007 | goto out_page; |
8a9f3ccd BS |
3008 | } |
3009 | ||
1da177e4 | 3010 | /* |
8f4e2101 | 3011 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 3012 | */ |
8f4e2101 | 3013 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
9e9bef07 | 3014 | if (unlikely(!pte_same(*page_table, orig_pte))) |
b8107480 | 3015 | goto out_nomap; |
b8107480 KK |
3016 | |
3017 | if (unlikely(!PageUptodate(page))) { | |
3018 | ret = VM_FAULT_SIGBUS; | |
3019 | goto out_nomap; | |
1da177e4 LT |
3020 | } |
3021 | ||
8c7c6e34 KH |
3022 | /* |
3023 | * The page isn't present yet, go ahead with the fault. | |
3024 | * | |
3025 | * Be careful about the sequence of operations here. | |
3026 | * To get its accounting right, reuse_swap_page() must be called | |
3027 | * while the page is counted on swap but not yet in mapcount i.e. | |
3028 | * before page_add_anon_rmap() and swap_free(); try_to_free_swap() | |
3029 | * must be called after the swap_free(), or it will never succeed. | |
03f3c433 KH |
3030 | * Because delete_from_swap_page() may be called by reuse_swap_page(), |
3031 | * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry | |
3032 | * in page->private. In this case, a record in swap_cgroup is silently | |
3033 | * discarded at swap_free(). | |
8c7c6e34 | 3034 | */ |
1da177e4 | 3035 | |
34e55232 | 3036 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
b084d435 | 3037 | dec_mm_counter_fast(mm, MM_SWAPENTS); |
1da177e4 | 3038 | pte = mk_pte(page, vma->vm_page_prot); |
30c9f3a9 | 3039 | if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) { |
1da177e4 | 3040 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); |
30c9f3a9 | 3041 | flags &= ~FAULT_FLAG_WRITE; |
9a5b489b | 3042 | ret |= VM_FAULT_WRITE; |
ad8c2ee8 | 3043 | exclusive = 1; |
1da177e4 | 3044 | } |
1da177e4 LT |
3045 | flush_icache_page(vma, page); |
3046 | set_pte_at(mm, address, page_table, pte); | |
ad8c2ee8 | 3047 | do_page_add_anon_rmap(page, vma, address, exclusive); |
03f3c433 KH |
3048 | /* It's better to call commit-charge after rmap is established */ |
3049 | mem_cgroup_commit_charge_swapin(page, ptr); | |
1da177e4 | 3050 | |
c475a8ab | 3051 | swap_free(entry); |
b291f000 | 3052 | if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) |
a2c43eed | 3053 | try_to_free_swap(page); |
c475a8ab | 3054 | unlock_page(page); |
4969c119 AA |
3055 | if (swapcache) { |
3056 | /* | |
3057 | * Hold the lock to avoid the swap entry to be reused | |
3058 | * until we take the PT lock for the pte_same() check | |
3059 | * (to avoid false positives from pte_same). For | |
3060 | * further safety release the lock after the swap_free | |
3061 | * so that the swap count won't change under a | |
3062 | * parallel locked swapcache. | |
3063 | */ | |
3064 | unlock_page(swapcache); | |
3065 | page_cache_release(swapcache); | |
3066 | } | |
c475a8ab | 3067 | |
30c9f3a9 | 3068 | if (flags & FAULT_FLAG_WRITE) { |
61469f1d HD |
3069 | ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); |
3070 | if (ret & VM_FAULT_ERROR) | |
3071 | ret &= VM_FAULT_ERROR; | |
1da177e4 LT |
3072 | goto out; |
3073 | } | |
3074 | ||
3075 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 3076 | update_mmu_cache(vma, address, page_table); |
65500d23 | 3077 | unlock: |
8f4e2101 | 3078 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
3079 | out: |
3080 | return ret; | |
b8107480 | 3081 | out_nomap: |
7a81b88c | 3082 | mem_cgroup_cancel_charge_swapin(ptr); |
8f4e2101 | 3083 | pte_unmap_unlock(page_table, ptl); |
bc43f75c | 3084 | out_page: |
b8107480 | 3085 | unlock_page(page); |
4779cb31 | 3086 | out_release: |
b8107480 | 3087 | page_cache_release(page); |
4969c119 AA |
3088 | if (swapcache) { |
3089 | unlock_page(swapcache); | |
3090 | page_cache_release(swapcache); | |
3091 | } | |
65500d23 | 3092 | return ret; |
1da177e4 LT |
3093 | } |
3094 | ||
320b2b8d | 3095 | /* |
8ca3eb08 TL |
3096 | * This is like a special single-page "expand_{down|up}wards()", |
3097 | * except we must first make sure that 'address{-|+}PAGE_SIZE' | |
320b2b8d | 3098 | * doesn't hit another vma. |
320b2b8d LT |
3099 | */ |
3100 | static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address) | |
3101 | { | |
3102 | address &= PAGE_MASK; | |
3103 | if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) { | |
0e8e50e2 LT |
3104 | struct vm_area_struct *prev = vma->vm_prev; |
3105 | ||
3106 | /* | |
3107 | * Is there a mapping abutting this one below? | |
3108 | * | |
3109 | * That's only ok if it's the same stack mapping | |
3110 | * that has gotten split.. | |
3111 | */ | |
3112 | if (prev && prev->vm_end == address) | |
3113 | return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; | |
320b2b8d | 3114 | |
d05f3169 | 3115 | expand_downwards(vma, address - PAGE_SIZE); |
320b2b8d | 3116 | } |
8ca3eb08 TL |
3117 | if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { |
3118 | struct vm_area_struct *next = vma->vm_next; | |
3119 | ||
3120 | /* As VM_GROWSDOWN but s/below/above/ */ | |
3121 | if (next && next->vm_start == address + PAGE_SIZE) | |
3122 | return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM; | |
3123 | ||
3124 | expand_upwards(vma, address + PAGE_SIZE); | |
3125 | } | |
320b2b8d LT |
3126 | return 0; |
3127 | } | |
3128 | ||
1da177e4 | 3129 | /* |
8f4e2101 HD |
3130 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
3131 | * but allow concurrent faults), and pte mapped but not yet locked. | |
3132 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 3133 | */ |
65500d23 HD |
3134 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
3135 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 3136 | unsigned int flags) |
1da177e4 | 3137 | { |
8f4e2101 HD |
3138 | struct page *page; |
3139 | spinlock_t *ptl; | |
1da177e4 | 3140 | pte_t entry; |
1da177e4 | 3141 | |
11ac5524 LT |
3142 | pte_unmap(page_table); |
3143 | ||
3144 | /* Check if we need to add a guard page to the stack */ | |
3145 | if (check_stack_guard_page(vma, address) < 0) | |
320b2b8d LT |
3146 | return VM_FAULT_SIGBUS; |
3147 | ||
11ac5524 | 3148 | /* Use the zero-page for reads */ |
62eede62 HD |
3149 | if (!(flags & FAULT_FLAG_WRITE)) { |
3150 | entry = pte_mkspecial(pfn_pte(my_zero_pfn(address), | |
3151 | vma->vm_page_prot)); | |
11ac5524 | 3152 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
a13ea5b7 HD |
3153 | if (!pte_none(*page_table)) |
3154 | goto unlock; | |
3155 | goto setpte; | |
3156 | } | |
3157 | ||
557ed1fa | 3158 | /* Allocate our own private page. */ |
557ed1fa NP |
3159 | if (unlikely(anon_vma_prepare(vma))) |
3160 | goto oom; | |
3161 | page = alloc_zeroed_user_highpage_movable(vma, address); | |
3162 | if (!page) | |
3163 | goto oom; | |
0ed361de | 3164 | __SetPageUptodate(page); |
8f4e2101 | 3165 | |
2c26fdd7 | 3166 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
3167 | goto oom_free_page; |
3168 | ||
557ed1fa | 3169 | entry = mk_pte(page, vma->vm_page_prot); |
1ac0cb5d HD |
3170 | if (vma->vm_flags & VM_WRITE) |
3171 | entry = pte_mkwrite(pte_mkdirty(entry)); | |
1da177e4 | 3172 | |
557ed1fa | 3173 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1c2fb7a4 | 3174 | if (!pte_none(*page_table)) |
557ed1fa | 3175 | goto release; |
9ba69294 | 3176 | |
34e55232 | 3177 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
557ed1fa | 3178 | page_add_new_anon_rmap(page, vma, address); |
a13ea5b7 | 3179 | setpte: |
65500d23 | 3180 | set_pte_at(mm, address, page_table, entry); |
1da177e4 LT |
3181 | |
3182 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 3183 | update_mmu_cache(vma, address, page_table); |
65500d23 | 3184 | unlock: |
8f4e2101 | 3185 | pte_unmap_unlock(page_table, ptl); |
83c54070 | 3186 | return 0; |
8f4e2101 | 3187 | release: |
8a9f3ccd | 3188 | mem_cgroup_uncharge_page(page); |
8f4e2101 HD |
3189 | page_cache_release(page); |
3190 | goto unlock; | |
8a9f3ccd | 3191 | oom_free_page: |
6dbf6d3b | 3192 | page_cache_release(page); |
65500d23 | 3193 | oom: |
1da177e4 LT |
3194 | return VM_FAULT_OOM; |
3195 | } | |
3196 | ||
3197 | /* | |
54cb8821 | 3198 | * __do_fault() tries to create a new page mapping. It aggressively |
1da177e4 | 3199 | * tries to share with existing pages, but makes a separate copy if |
54cb8821 NP |
3200 | * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid |
3201 | * the next page fault. | |
1da177e4 LT |
3202 | * |
3203 | * As this is called only for pages that do not currently exist, we | |
3204 | * do not need to flush old virtual caches or the TLB. | |
3205 | * | |
8f4e2101 | 3206 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
16abfa08 | 3207 | * but allow concurrent faults), and pte neither mapped nor locked. |
8f4e2101 | 3208 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
1da177e4 | 3209 | */ |
54cb8821 | 3210 | static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
16abfa08 | 3211 | unsigned long address, pmd_t *pmd, |
54cb8821 | 3212 | pgoff_t pgoff, unsigned int flags, pte_t orig_pte) |
1da177e4 | 3213 | { |
16abfa08 | 3214 | pte_t *page_table; |
8f4e2101 | 3215 | spinlock_t *ptl; |
d0217ac0 | 3216 | struct page *page; |
1d65f86d | 3217 | struct page *cow_page; |
1da177e4 | 3218 | pte_t entry; |
1da177e4 | 3219 | int anon = 0; |
d08b3851 | 3220 | struct page *dirty_page = NULL; |
d0217ac0 NP |
3221 | struct vm_fault vmf; |
3222 | int ret; | |
a200ee18 | 3223 | int page_mkwrite = 0; |
54cb8821 | 3224 | |
1d65f86d KH |
3225 | /* |
3226 | * If we do COW later, allocate page befor taking lock_page() | |
3227 | * on the file cache page. This will reduce lock holding time. | |
3228 | */ | |
3229 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { | |
3230 | ||
3231 | if (unlikely(anon_vma_prepare(vma))) | |
3232 | return VM_FAULT_OOM; | |
3233 | ||
3234 | cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
3235 | if (!cow_page) | |
3236 | return VM_FAULT_OOM; | |
3237 | ||
3238 | if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) { | |
3239 | page_cache_release(cow_page); | |
3240 | return VM_FAULT_OOM; | |
3241 | } | |
3242 | } else | |
3243 | cow_page = NULL; | |
3244 | ||
d0217ac0 NP |
3245 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); |
3246 | vmf.pgoff = pgoff; | |
3247 | vmf.flags = flags; | |
3248 | vmf.page = NULL; | |
1da177e4 | 3249 | |
3c18ddd1 | 3250 | ret = vma->vm_ops->fault(vma, &vmf); |
d065bd81 ML |
3251 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | |
3252 | VM_FAULT_RETRY))) | |
1d65f86d | 3253 | goto uncharge_out; |
1da177e4 | 3254 | |
a3b947ea AK |
3255 | if (unlikely(PageHWPoison(vmf.page))) { |
3256 | if (ret & VM_FAULT_LOCKED) | |
3257 | unlock_page(vmf.page); | |
1d65f86d KH |
3258 | ret = VM_FAULT_HWPOISON; |
3259 | goto uncharge_out; | |
a3b947ea AK |
3260 | } |
3261 | ||
d00806b1 | 3262 | /* |
d0217ac0 | 3263 | * For consistency in subsequent calls, make the faulted page always |
d00806b1 NP |
3264 | * locked. |
3265 | */ | |
83c54070 | 3266 | if (unlikely(!(ret & VM_FAULT_LOCKED))) |
d0217ac0 | 3267 | lock_page(vmf.page); |
54cb8821 | 3268 | else |
d0217ac0 | 3269 | VM_BUG_ON(!PageLocked(vmf.page)); |
d00806b1 | 3270 | |
1da177e4 LT |
3271 | /* |
3272 | * Should we do an early C-O-W break? | |
3273 | */ | |
d0217ac0 | 3274 | page = vmf.page; |
54cb8821 | 3275 | if (flags & FAULT_FLAG_WRITE) { |
9637a5ef | 3276 | if (!(vma->vm_flags & VM_SHARED)) { |
1d65f86d | 3277 | page = cow_page; |
54cb8821 | 3278 | anon = 1; |
d0217ac0 | 3279 | copy_user_highpage(page, vmf.page, address, vma); |
0ed361de | 3280 | __SetPageUptodate(page); |
9637a5ef | 3281 | } else { |
54cb8821 NP |
3282 | /* |
3283 | * If the page will be shareable, see if the backing | |
9637a5ef | 3284 | * address space wants to know that the page is about |
54cb8821 NP |
3285 | * to become writable |
3286 | */ | |
69676147 | 3287 | if (vma->vm_ops->page_mkwrite) { |
c2ec175c NP |
3288 | int tmp; |
3289 | ||
69676147 | 3290 | unlock_page(page); |
b827e496 | 3291 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; |
c2ec175c NP |
3292 | tmp = vma->vm_ops->page_mkwrite(vma, &vmf); |
3293 | if (unlikely(tmp & | |
3294 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { | |
3295 | ret = tmp; | |
b827e496 | 3296 | goto unwritable_page; |
d0217ac0 | 3297 | } |
b827e496 NP |
3298 | if (unlikely(!(tmp & VM_FAULT_LOCKED))) { |
3299 | lock_page(page); | |
3300 | if (!page->mapping) { | |
3301 | ret = 0; /* retry the fault */ | |
3302 | unlock_page(page); | |
3303 | goto unwritable_page; | |
3304 | } | |
3305 | } else | |
3306 | VM_BUG_ON(!PageLocked(page)); | |
a200ee18 | 3307 | page_mkwrite = 1; |
9637a5ef DH |
3308 | } |
3309 | } | |
54cb8821 | 3310 | |
1da177e4 LT |
3311 | } |
3312 | ||
8f4e2101 | 3313 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
3314 | |
3315 | /* | |
3316 | * This silly early PAGE_DIRTY setting removes a race | |
3317 | * due to the bad i386 page protection. But it's valid | |
3318 | * for other architectures too. | |
3319 | * | |
30c9f3a9 | 3320 | * Note that if FAULT_FLAG_WRITE is set, we either now have |
1da177e4 LT |
3321 | * an exclusive copy of the page, or this is a shared mapping, |
3322 | * so we can make it writable and dirty to avoid having to | |
3323 | * handle that later. | |
3324 | */ | |
3325 | /* Only go through if we didn't race with anybody else... */ | |
1c2fb7a4 | 3326 | if (likely(pte_same(*page_table, orig_pte))) { |
d00806b1 NP |
3327 | flush_icache_page(vma, page); |
3328 | entry = mk_pte(page, vma->vm_page_prot); | |
54cb8821 | 3329 | if (flags & FAULT_FLAG_WRITE) |
1da177e4 | 3330 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
1da177e4 | 3331 | if (anon) { |
34e55232 | 3332 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
64d6519d | 3333 | page_add_new_anon_rmap(page, vma, address); |
f57e88a8 | 3334 | } else { |
34e55232 | 3335 | inc_mm_counter_fast(mm, MM_FILEPAGES); |
d00806b1 | 3336 | page_add_file_rmap(page); |
54cb8821 | 3337 | if (flags & FAULT_FLAG_WRITE) { |
d00806b1 | 3338 | dirty_page = page; |
d08b3851 PZ |
3339 | get_page(dirty_page); |
3340 | } | |
4294621f | 3341 | } |
64d6519d | 3342 | set_pte_at(mm, address, page_table, entry); |
d00806b1 NP |
3343 | |
3344 | /* no need to invalidate: a not-present page won't be cached */ | |
4b3073e1 | 3345 | update_mmu_cache(vma, address, page_table); |
1da177e4 | 3346 | } else { |
1d65f86d KH |
3347 | if (cow_page) |
3348 | mem_cgroup_uncharge_page(cow_page); | |
d00806b1 NP |
3349 | if (anon) |
3350 | page_cache_release(page); | |
3351 | else | |
54cb8821 | 3352 | anon = 1; /* no anon but release faulted_page */ |
1da177e4 LT |
3353 | } |
3354 | ||
8f4e2101 | 3355 | pte_unmap_unlock(page_table, ptl); |
d00806b1 | 3356 | |
b827e496 NP |
3357 | if (dirty_page) { |
3358 | struct address_space *mapping = page->mapping; | |
41c4d25f | 3359 | int dirtied = 0; |
8f7b3d15 | 3360 | |
b827e496 | 3361 | if (set_page_dirty(dirty_page)) |
41c4d25f | 3362 | dirtied = 1; |
b827e496 | 3363 | unlock_page(dirty_page); |
d08b3851 | 3364 | put_page(dirty_page); |
41c4d25f | 3365 | if ((dirtied || page_mkwrite) && mapping) { |
b827e496 NP |
3366 | /* |
3367 | * Some device drivers do not set page.mapping but still | |
3368 | * dirty their pages | |
3369 | */ | |
3370 | balance_dirty_pages_ratelimited(mapping); | |
3371 | } | |
3372 | ||
3373 | /* file_update_time outside page_lock */ | |
41c4d25f | 3374 | if (vma->vm_file && !page_mkwrite) |
b827e496 NP |
3375 | file_update_time(vma->vm_file); |
3376 | } else { | |
3377 | unlock_page(vmf.page); | |
3378 | if (anon) | |
3379 | page_cache_release(vmf.page); | |
d08b3851 | 3380 | } |
d00806b1 | 3381 | |
83c54070 | 3382 | return ret; |
b827e496 NP |
3383 | |
3384 | unwritable_page: | |
3385 | page_cache_release(page); | |
3386 | return ret; | |
1d65f86d KH |
3387 | uncharge_out: |
3388 | /* fs's fault handler get error */ | |
3389 | if (cow_page) { | |
3390 | mem_cgroup_uncharge_page(cow_page); | |
3391 | page_cache_release(cow_page); | |
3392 | } | |
3393 | return ret; | |
54cb8821 | 3394 | } |
d00806b1 | 3395 | |
54cb8821 NP |
3396 | static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
3397 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 3398 | unsigned int flags, pte_t orig_pte) |
54cb8821 NP |
3399 | { |
3400 | pgoff_t pgoff = (((address & PAGE_MASK) | |
0da7e01f | 3401 | - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
54cb8821 | 3402 | |
16abfa08 HD |
3403 | pte_unmap(page_table); |
3404 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); | |
54cb8821 NP |
3405 | } |
3406 | ||
1da177e4 LT |
3407 | /* |
3408 | * Fault of a previously existing named mapping. Repopulate the pte | |
3409 | * from the encoded file_pte if possible. This enables swappable | |
3410 | * nonlinear vmas. | |
8f4e2101 HD |
3411 | * |
3412 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
3413 | * but allow concurrent faults), and pte mapped but not yet locked. | |
3414 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 3415 | */ |
d0217ac0 | 3416 | static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
65500d23 | 3417 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
30c9f3a9 | 3418 | unsigned int flags, pte_t orig_pte) |
1da177e4 | 3419 | { |
65500d23 | 3420 | pgoff_t pgoff; |
1da177e4 | 3421 | |
30c9f3a9 LT |
3422 | flags |= FAULT_FLAG_NONLINEAR; |
3423 | ||
4c21e2f2 | 3424 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
83c54070 | 3425 | return 0; |
1da177e4 | 3426 | |
2509ef26 | 3427 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { |
65500d23 HD |
3428 | /* |
3429 | * Page table corrupted: show pte and kill process. | |
3430 | */ | |
3dc14741 | 3431 | print_bad_pte(vma, address, orig_pte, NULL); |
d99be1a8 | 3432 | return VM_FAULT_SIGBUS; |
65500d23 | 3433 | } |
65500d23 HD |
3434 | |
3435 | pgoff = pte_to_pgoff(orig_pte); | |
16abfa08 | 3436 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); |
1da177e4 LT |
3437 | } |
3438 | ||
9532fec1 MG |
3439 | int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, |
3440 | unsigned long addr, int current_nid) | |
3441 | { | |
3442 | get_page(page); | |
3443 | ||
3444 | count_vm_numa_event(NUMA_HINT_FAULTS); | |
3445 | if (current_nid == numa_node_id()) | |
3446 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); | |
3447 | ||
3448 | return mpol_misplaced(page, vma, addr); | |
3449 | } | |
3450 | ||
d10e63f2 MG |
3451 | int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, |
3452 | unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd) | |
3453 | { | |
4daae3b4 | 3454 | struct page *page = NULL; |
d10e63f2 | 3455 | spinlock_t *ptl; |
cbee9f88 PZ |
3456 | int current_nid = -1; |
3457 | int target_nid; | |
b8593bfd | 3458 | bool migrated = false; |
d10e63f2 MG |
3459 | |
3460 | /* | |
3461 | * The "pte" at this point cannot be used safely without | |
3462 | * validation through pte_unmap_same(). It's of NUMA type but | |
3463 | * the pfn may be screwed if the read is non atomic. | |
3464 | * | |
3465 | * ptep_modify_prot_start is not called as this is clearing | |
3466 | * the _PAGE_NUMA bit and it is not really expected that there | |
3467 | * would be concurrent hardware modifications to the PTE. | |
3468 | */ | |
3469 | ptl = pte_lockptr(mm, pmd); | |
3470 | spin_lock(ptl); | |
4daae3b4 MG |
3471 | if (unlikely(!pte_same(*ptep, pte))) { |
3472 | pte_unmap_unlock(ptep, ptl); | |
3473 | goto out; | |
3474 | } | |
3475 | ||
d10e63f2 MG |
3476 | pte = pte_mknonnuma(pte); |
3477 | set_pte_at(mm, addr, ptep, pte); | |
3478 | update_mmu_cache(vma, addr, ptep); | |
3479 | ||
3480 | page = vm_normal_page(vma, addr, pte); | |
3481 | if (!page) { | |
3482 | pte_unmap_unlock(ptep, ptl); | |
3483 | return 0; | |
3484 | } | |
3485 | ||
4daae3b4 | 3486 | current_nid = page_to_nid(page); |
9532fec1 | 3487 | target_nid = numa_migrate_prep(page, vma, addr, current_nid); |
d10e63f2 | 3488 | pte_unmap_unlock(ptep, ptl); |
4daae3b4 MG |
3489 | if (target_nid == -1) { |
3490 | /* | |
3491 | * Account for the fault against the current node if it not | |
3492 | * being replaced regardless of where the page is located. | |
3493 | */ | |
3494 | current_nid = numa_node_id(); | |
3495 | put_page(page); | |
3496 | goto out; | |
3497 | } | |
3498 | ||
3499 | /* Migrate to the requested node */ | |
b8593bfd MG |
3500 | migrated = migrate_misplaced_page(page, target_nid); |
3501 | if (migrated) | |
4daae3b4 MG |
3502 | current_nid = target_nid; |
3503 | ||
3504 | out: | |
9532fec1 | 3505 | if (current_nid != -1) |
b8593bfd | 3506 | task_numa_fault(current_nid, 1, migrated); |
d10e63f2 MG |
3507 | return 0; |
3508 | } | |
3509 | ||
3510 | /* NUMA hinting page fault entry point for regular pmds */ | |
3511 | #ifdef CONFIG_NUMA_BALANCING | |
3512 | static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
3513 | unsigned long addr, pmd_t *pmdp) | |
3514 | { | |
3515 | pmd_t pmd; | |
3516 | pte_t *pte, *orig_pte; | |
3517 | unsigned long _addr = addr & PMD_MASK; | |
3518 | unsigned long offset; | |
3519 | spinlock_t *ptl; | |
3520 | bool numa = false; | |
03c5a6e1 | 3521 | int local_nid = numa_node_id(); |
d10e63f2 MG |
3522 | |
3523 | spin_lock(&mm->page_table_lock); | |
3524 | pmd = *pmdp; | |
3525 | if (pmd_numa(pmd)) { | |
3526 | set_pmd_at(mm, _addr, pmdp, pmd_mknonnuma(pmd)); | |
3527 | numa = true; | |
3528 | } | |
3529 | spin_unlock(&mm->page_table_lock); | |
3530 | ||
3531 | if (!numa) | |
3532 | return 0; | |
3533 | ||
3534 | /* we're in a page fault so some vma must be in the range */ | |
3535 | BUG_ON(!vma); | |
3536 | BUG_ON(vma->vm_start >= _addr + PMD_SIZE); | |
3537 | offset = max(_addr, vma->vm_start) & ~PMD_MASK; | |
3538 | VM_BUG_ON(offset >= PMD_SIZE); | |
3539 | orig_pte = pte = pte_offset_map_lock(mm, pmdp, _addr, &ptl); | |
3540 | pte += offset >> PAGE_SHIFT; | |
3541 | for (addr = _addr + offset; addr < _addr + PMD_SIZE; pte++, addr += PAGE_SIZE) { | |
3542 | pte_t pteval = *pte; | |
3543 | struct page *page; | |
9532fec1 MG |
3544 | int curr_nid = local_nid; |
3545 | int target_nid; | |
b8593bfd | 3546 | bool migrated; |
d10e63f2 MG |
3547 | if (!pte_present(pteval)) |
3548 | continue; | |
3549 | if (!pte_numa(pteval)) | |
3550 | continue; | |
3551 | if (addr >= vma->vm_end) { | |
3552 | vma = find_vma(mm, addr); | |
3553 | /* there's a pte present so there must be a vma */ | |
3554 | BUG_ON(!vma); | |
3555 | BUG_ON(addr < vma->vm_start); | |
3556 | } | |
3557 | if (pte_numa(pteval)) { | |
3558 | pteval = pte_mknonnuma(pteval); | |
3559 | set_pte_at(mm, addr, pte, pteval); | |
3560 | } | |
3561 | page = vm_normal_page(vma, addr, pteval); | |
3562 | if (unlikely(!page)) | |
3563 | continue; | |
cbee9f88 PZ |
3564 | /* only check non-shared pages */ |
3565 | if (unlikely(page_mapcount(page) != 1)) | |
3566 | continue; | |
cbee9f88 | 3567 | |
9532fec1 MG |
3568 | /* |
3569 | * Note that the NUMA fault is later accounted to either | |
3570 | * the node that is currently running or where the page is | |
3571 | * migrated to. | |
3572 | */ | |
3573 | curr_nid = local_nid; | |
3574 | target_nid = numa_migrate_prep(page, vma, addr, | |
3575 | page_to_nid(page)); | |
3576 | if (target_nid == -1) { | |
3577 | put_page(page); | |
3578 | continue; | |
3579 | } | |
cbee9f88 | 3580 | |
9532fec1 MG |
3581 | /* Migrate to the requested node */ |
3582 | pte_unmap_unlock(pte, ptl); | |
b8593bfd MG |
3583 | migrated = migrate_misplaced_page(page, target_nid); |
3584 | if (migrated) | |
9532fec1 | 3585 | curr_nid = target_nid; |
b8593bfd | 3586 | task_numa_fault(curr_nid, 1, migrated); |
03c5a6e1 | 3587 | |
cbee9f88 | 3588 | pte = pte_offset_map_lock(mm, pmdp, addr, &ptl); |
d10e63f2 MG |
3589 | } |
3590 | pte_unmap_unlock(orig_pte, ptl); | |
3591 | ||
3592 | return 0; | |
3593 | } | |
3594 | #else | |
3595 | static int do_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, | |
3596 | unsigned long addr, pmd_t *pmdp) | |
3597 | { | |
3598 | BUG(); | |
b3dd2070 | 3599 | return 0; |
d10e63f2 MG |
3600 | } |
3601 | #endif /* CONFIG_NUMA_BALANCING */ | |
3602 | ||
1da177e4 LT |
3603 | /* |
3604 | * These routines also need to handle stuff like marking pages dirty | |
3605 | * and/or accessed for architectures that don't do it in hardware (most | |
3606 | * RISC architectures). The early dirtying is also good on the i386. | |
3607 | * | |
3608 | * There is also a hook called "update_mmu_cache()" that architectures | |
3609 | * with external mmu caches can use to update those (ie the Sparc or | |
3610 | * PowerPC hashed page tables that act as extended TLBs). | |
3611 | * | |
c74df32c HD |
3612 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
3613 | * but allow concurrent faults), and pte mapped but not yet locked. | |
3614 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 3615 | */ |
71e3aac0 AA |
3616 | int handle_pte_fault(struct mm_struct *mm, |
3617 | struct vm_area_struct *vma, unsigned long address, | |
3618 | pte_t *pte, pmd_t *pmd, unsigned int flags) | |
1da177e4 LT |
3619 | { |
3620 | pte_t entry; | |
8f4e2101 | 3621 | spinlock_t *ptl; |
1da177e4 | 3622 | |
8dab5241 | 3623 | entry = *pte; |
1da177e4 | 3624 | if (!pte_present(entry)) { |
65500d23 | 3625 | if (pte_none(entry)) { |
f4b81804 | 3626 | if (vma->vm_ops) { |
3c18ddd1 | 3627 | if (likely(vma->vm_ops->fault)) |
54cb8821 | 3628 | return do_linear_fault(mm, vma, address, |
30c9f3a9 | 3629 | pte, pmd, flags, entry); |
f4b81804 JS |
3630 | } |
3631 | return do_anonymous_page(mm, vma, address, | |
30c9f3a9 | 3632 | pte, pmd, flags); |
65500d23 | 3633 | } |
1da177e4 | 3634 | if (pte_file(entry)) |
d0217ac0 | 3635 | return do_nonlinear_fault(mm, vma, address, |
30c9f3a9 | 3636 | pte, pmd, flags, entry); |
65500d23 | 3637 | return do_swap_page(mm, vma, address, |
30c9f3a9 | 3638 | pte, pmd, flags, entry); |
1da177e4 LT |
3639 | } |
3640 | ||
d10e63f2 MG |
3641 | if (pte_numa(entry)) |
3642 | return do_numa_page(mm, vma, address, entry, pte, pmd); | |
3643 | ||
4c21e2f2 | 3644 | ptl = pte_lockptr(mm, pmd); |
8f4e2101 HD |
3645 | spin_lock(ptl); |
3646 | if (unlikely(!pte_same(*pte, entry))) | |
3647 | goto unlock; | |
30c9f3a9 | 3648 | if (flags & FAULT_FLAG_WRITE) { |
1da177e4 | 3649 | if (!pte_write(entry)) |
8f4e2101 HD |
3650 | return do_wp_page(mm, vma, address, |
3651 | pte, pmd, ptl, entry); | |
1da177e4 LT |
3652 | entry = pte_mkdirty(entry); |
3653 | } | |
3654 | entry = pte_mkyoung(entry); | |
30c9f3a9 | 3655 | if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) { |
4b3073e1 | 3656 | update_mmu_cache(vma, address, pte); |
1a44e149 AA |
3657 | } else { |
3658 | /* | |
3659 | * This is needed only for protection faults but the arch code | |
3660 | * is not yet telling us if this is a protection fault or not. | |
3661 | * This still avoids useless tlb flushes for .text page faults | |
3662 | * with threads. | |
3663 | */ | |
30c9f3a9 | 3664 | if (flags & FAULT_FLAG_WRITE) |
61c77326 | 3665 | flush_tlb_fix_spurious_fault(vma, address); |
1a44e149 | 3666 | } |
8f4e2101 HD |
3667 | unlock: |
3668 | pte_unmap_unlock(pte, ptl); | |
83c54070 | 3669 | return 0; |
1da177e4 LT |
3670 | } |
3671 | ||
3672 | /* | |
3673 | * By the time we get here, we already hold the mm semaphore | |
3674 | */ | |
83c54070 | 3675 | int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
d06063cc | 3676 | unsigned long address, unsigned int flags) |
1da177e4 LT |
3677 | { |
3678 | pgd_t *pgd; | |
3679 | pud_t *pud; | |
3680 | pmd_t *pmd; | |
3681 | pte_t *pte; | |
3682 | ||
3683 | __set_current_state(TASK_RUNNING); | |
3684 | ||
f8891e5e | 3685 | count_vm_event(PGFAULT); |
456f998e | 3686 | mem_cgroup_count_vm_event(mm, PGFAULT); |
1da177e4 | 3687 | |
34e55232 KH |
3688 | /* do counter updates before entering really critical section. */ |
3689 | check_sync_rss_stat(current); | |
3690 | ||
ac9b9c66 | 3691 | if (unlikely(is_vm_hugetlb_page(vma))) |
30c9f3a9 | 3692 | return hugetlb_fault(mm, vma, address, flags); |
1da177e4 | 3693 | |
1f1d06c3 | 3694 | retry: |
1da177e4 | 3695 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
3696 | pud = pud_alloc(mm, pgd, address); |
3697 | if (!pud) | |
c74df32c | 3698 | return VM_FAULT_OOM; |
1da177e4 LT |
3699 | pmd = pmd_alloc(mm, pud, address); |
3700 | if (!pmd) | |
c74df32c | 3701 | return VM_FAULT_OOM; |
71e3aac0 AA |
3702 | if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) { |
3703 | if (!vma->vm_ops) | |
3704 | return do_huge_pmd_anonymous_page(mm, vma, address, | |
3705 | pmd, flags); | |
3706 | } else { | |
3707 | pmd_t orig_pmd = *pmd; | |
1f1d06c3 DR |
3708 | int ret; |
3709 | ||
71e3aac0 AA |
3710 | barrier(); |
3711 | if (pmd_trans_huge(orig_pmd)) { | |
a1dd450b WD |
3712 | unsigned int dirty = flags & FAULT_FLAG_WRITE; |
3713 | ||
e53289c0 LT |
3714 | /* |
3715 | * If the pmd is splitting, return and retry the | |
3716 | * the fault. Alternative: wait until the split | |
3717 | * is done, and goto retry. | |
3718 | */ | |
3719 | if (pmd_trans_splitting(orig_pmd)) | |
3720 | return 0; | |
3721 | ||
3d59eebc | 3722 | if (pmd_numa(orig_pmd)) |
4daae3b4 | 3723 | return do_huge_pmd_numa_page(mm, vma, address, |
d10e63f2 MG |
3724 | orig_pmd, pmd); |
3725 | ||
3d59eebc | 3726 | if (dirty && !pmd_write(orig_pmd)) { |
1f1d06c3 DR |
3727 | ret = do_huge_pmd_wp_page(mm, vma, address, pmd, |
3728 | orig_pmd); | |
3729 | /* | |
3730 | * If COW results in an oom, the huge pmd will | |
3731 | * have been split, so retry the fault on the | |
3732 | * pte for a smaller charge. | |
3733 | */ | |
3734 | if (unlikely(ret & VM_FAULT_OOM)) | |
3735 | goto retry; | |
3736 | return ret; | |
a1dd450b WD |
3737 | } else { |
3738 | huge_pmd_set_accessed(mm, vma, address, pmd, | |
3739 | orig_pmd, dirty); | |
1f1d06c3 | 3740 | } |
d10e63f2 | 3741 | |
71e3aac0 AA |
3742 | return 0; |
3743 | } | |
3744 | } | |
3745 | ||
d10e63f2 MG |
3746 | if (pmd_numa(*pmd)) |
3747 | return do_pmd_numa_page(mm, vma, address, pmd); | |
3748 | ||
71e3aac0 AA |
3749 | /* |
3750 | * Use __pte_alloc instead of pte_alloc_map, because we can't | |
3751 | * run pte_offset_map on the pmd, if an huge pmd could | |
3752 | * materialize from under us from a different thread. | |
3753 | */ | |
4fd01770 MG |
3754 | if (unlikely(pmd_none(*pmd)) && |
3755 | unlikely(__pte_alloc(mm, vma, pmd, address))) | |
c74df32c | 3756 | return VM_FAULT_OOM; |
71e3aac0 AA |
3757 | /* if an huge pmd materialized from under us just retry later */ |
3758 | if (unlikely(pmd_trans_huge(*pmd))) | |
3759 | return 0; | |
3760 | /* | |
3761 | * A regular pmd is established and it can't morph into a huge pmd | |
3762 | * from under us anymore at this point because we hold the mmap_sem | |
3763 | * read mode and khugepaged takes it in write mode. So now it's | |
3764 | * safe to run pte_offset_map(). | |
3765 | */ | |
3766 | pte = pte_offset_map(pmd, address); | |
1da177e4 | 3767 | |
30c9f3a9 | 3768 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); |
1da177e4 LT |
3769 | } |
3770 | ||
3771 | #ifndef __PAGETABLE_PUD_FOLDED | |
3772 | /* | |
3773 | * Allocate page upper directory. | |
872fec16 | 3774 | * We've already handled the fast-path in-line. |
1da177e4 | 3775 | */ |
1bb3630e | 3776 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 3777 | { |
c74df32c HD |
3778 | pud_t *new = pud_alloc_one(mm, address); |
3779 | if (!new) | |
1bb3630e | 3780 | return -ENOMEM; |
1da177e4 | 3781 | |
362a61ad NP |
3782 | smp_wmb(); /* See comment in __pte_alloc */ |
3783 | ||
872fec16 | 3784 | spin_lock(&mm->page_table_lock); |
1bb3630e | 3785 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 3786 | pud_free(mm, new); |
1bb3630e HD |
3787 | else |
3788 | pgd_populate(mm, pgd, new); | |
c74df32c | 3789 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3790 | return 0; |
1da177e4 LT |
3791 | } |
3792 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
3793 | ||
3794 | #ifndef __PAGETABLE_PMD_FOLDED | |
3795 | /* | |
3796 | * Allocate page middle directory. | |
872fec16 | 3797 | * We've already handled the fast-path in-line. |
1da177e4 | 3798 | */ |
1bb3630e | 3799 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 3800 | { |
c74df32c HD |
3801 | pmd_t *new = pmd_alloc_one(mm, address); |
3802 | if (!new) | |
1bb3630e | 3803 | return -ENOMEM; |
1da177e4 | 3804 | |
362a61ad NP |
3805 | smp_wmb(); /* See comment in __pte_alloc */ |
3806 | ||
872fec16 | 3807 | spin_lock(&mm->page_table_lock); |
1da177e4 | 3808 | #ifndef __ARCH_HAS_4LEVEL_HACK |
1bb3630e | 3809 | if (pud_present(*pud)) /* Another has populated it */ |
5e541973 | 3810 | pmd_free(mm, new); |
1bb3630e HD |
3811 | else |
3812 | pud_populate(mm, pud, new); | |
1da177e4 | 3813 | #else |
1bb3630e | 3814 | if (pgd_present(*pud)) /* Another has populated it */ |
5e541973 | 3815 | pmd_free(mm, new); |
1bb3630e HD |
3816 | else |
3817 | pgd_populate(mm, pud, new); | |
1da177e4 | 3818 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 3819 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3820 | return 0; |
e0f39591 | 3821 | } |
1da177e4 LT |
3822 | #endif /* __PAGETABLE_PMD_FOLDED */ |
3823 | ||
3824 | int make_pages_present(unsigned long addr, unsigned long end) | |
3825 | { | |
3826 | int ret, len, write; | |
3827 | struct vm_area_struct * vma; | |
3828 | ||
3829 | vma = find_vma(current->mm, addr); | |
3830 | if (!vma) | |
a477097d | 3831 | return -ENOMEM; |
5ecfda04 ML |
3832 | /* |
3833 | * We want to touch writable mappings with a write fault in order | |
3834 | * to break COW, except for shared mappings because these don't COW | |
3835 | * and we would not want to dirty them for nothing. | |
3836 | */ | |
3837 | write = (vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE; | |
5bcb28b1 ES |
3838 | BUG_ON(addr >= end); |
3839 | BUG_ON(end > vma->vm_end); | |
68e116a3 | 3840 | len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; |
1da177e4 LT |
3841 | ret = get_user_pages(current, current->mm, addr, |
3842 | len, write, 0, NULL, NULL); | |
c11d69d8 | 3843 | if (ret < 0) |
1da177e4 | 3844 | return ret; |
9978ad58 | 3845 | return ret == len ? 0 : -EFAULT; |
1da177e4 LT |
3846 | } |
3847 | ||
1da177e4 LT |
3848 | #if !defined(__HAVE_ARCH_GATE_AREA) |
3849 | ||
3850 | #if defined(AT_SYSINFO_EHDR) | |
5ce7852c | 3851 | static struct vm_area_struct gate_vma; |
1da177e4 LT |
3852 | |
3853 | static int __init gate_vma_init(void) | |
3854 | { | |
3855 | gate_vma.vm_mm = NULL; | |
3856 | gate_vma.vm_start = FIXADDR_USER_START; | |
3857 | gate_vma.vm_end = FIXADDR_USER_END; | |
b6558c4a RM |
3858 | gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; |
3859 | gate_vma.vm_page_prot = __P101; | |
909af768 | 3860 | |
1da177e4 LT |
3861 | return 0; |
3862 | } | |
3863 | __initcall(gate_vma_init); | |
3864 | #endif | |
3865 | ||
31db58b3 | 3866 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) |
1da177e4 LT |
3867 | { |
3868 | #ifdef AT_SYSINFO_EHDR | |
3869 | return &gate_vma; | |
3870 | #else | |
3871 | return NULL; | |
3872 | #endif | |
3873 | } | |
3874 | ||
cae5d390 | 3875 | int in_gate_area_no_mm(unsigned long addr) |
1da177e4 LT |
3876 | { |
3877 | #ifdef AT_SYSINFO_EHDR | |
3878 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) | |
3879 | return 1; | |
3880 | #endif | |
3881 | return 0; | |
3882 | } | |
3883 | ||
3884 | #endif /* __HAVE_ARCH_GATE_AREA */ | |
0ec76a11 | 3885 | |
1b36ba81 | 3886 | static int __follow_pte(struct mm_struct *mm, unsigned long address, |
f8ad0f49 JW |
3887 | pte_t **ptepp, spinlock_t **ptlp) |
3888 | { | |
3889 | pgd_t *pgd; | |
3890 | pud_t *pud; | |
3891 | pmd_t *pmd; | |
3892 | pte_t *ptep; | |
3893 | ||
3894 | pgd = pgd_offset(mm, address); | |
3895 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
3896 | goto out; | |
3897 | ||
3898 | pud = pud_offset(pgd, address); | |
3899 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
3900 | goto out; | |
3901 | ||
3902 | pmd = pmd_offset(pud, address); | |
f66055ab | 3903 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
f8ad0f49 JW |
3904 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) |
3905 | goto out; | |
3906 | ||
3907 | /* We cannot handle huge page PFN maps. Luckily they don't exist. */ | |
3908 | if (pmd_huge(*pmd)) | |
3909 | goto out; | |
3910 | ||
3911 | ptep = pte_offset_map_lock(mm, pmd, address, ptlp); | |
3912 | if (!ptep) | |
3913 | goto out; | |
3914 | if (!pte_present(*ptep)) | |
3915 | goto unlock; | |
3916 | *ptepp = ptep; | |
3917 | return 0; | |
3918 | unlock: | |
3919 | pte_unmap_unlock(ptep, *ptlp); | |
3920 | out: | |
3921 | return -EINVAL; | |
3922 | } | |
3923 | ||
1b36ba81 NK |
3924 | static inline int follow_pte(struct mm_struct *mm, unsigned long address, |
3925 | pte_t **ptepp, spinlock_t **ptlp) | |
3926 | { | |
3927 | int res; | |
3928 | ||
3929 | /* (void) is needed to make gcc happy */ | |
3930 | (void) __cond_lock(*ptlp, | |
3931 | !(res = __follow_pte(mm, address, ptepp, ptlp))); | |
3932 | return res; | |
3933 | } | |
3934 | ||
3b6748e2 JW |
3935 | /** |
3936 | * follow_pfn - look up PFN at a user virtual address | |
3937 | * @vma: memory mapping | |
3938 | * @address: user virtual address | |
3939 | * @pfn: location to store found PFN | |
3940 | * | |
3941 | * Only IO mappings and raw PFN mappings are allowed. | |
3942 | * | |
3943 | * Returns zero and the pfn at @pfn on success, -ve otherwise. | |
3944 | */ | |
3945 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, | |
3946 | unsigned long *pfn) | |
3947 | { | |
3948 | int ret = -EINVAL; | |
3949 | spinlock_t *ptl; | |
3950 | pte_t *ptep; | |
3951 | ||
3952 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
3953 | return ret; | |
3954 | ||
3955 | ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); | |
3956 | if (ret) | |
3957 | return ret; | |
3958 | *pfn = pte_pfn(*ptep); | |
3959 | pte_unmap_unlock(ptep, ptl); | |
3960 | return 0; | |
3961 | } | |
3962 | EXPORT_SYMBOL(follow_pfn); | |
3963 | ||
28b2ee20 | 3964 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
d87fe660 | 3965 | int follow_phys(struct vm_area_struct *vma, |
3966 | unsigned long address, unsigned int flags, | |
3967 | unsigned long *prot, resource_size_t *phys) | |
28b2ee20 | 3968 | { |
03668a4d | 3969 | int ret = -EINVAL; |
28b2ee20 RR |
3970 | pte_t *ptep, pte; |
3971 | spinlock_t *ptl; | |
28b2ee20 | 3972 | |
d87fe660 | 3973 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
3974 | goto out; | |
28b2ee20 | 3975 | |
03668a4d | 3976 | if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) |
d87fe660 | 3977 | goto out; |
28b2ee20 | 3978 | pte = *ptep; |
03668a4d | 3979 | |
28b2ee20 RR |
3980 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
3981 | goto unlock; | |
28b2ee20 RR |
3982 | |
3983 | *prot = pgprot_val(pte_pgprot(pte)); | |
03668a4d | 3984 | *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; |
28b2ee20 | 3985 | |
03668a4d | 3986 | ret = 0; |
28b2ee20 RR |
3987 | unlock: |
3988 | pte_unmap_unlock(ptep, ptl); | |
3989 | out: | |
d87fe660 | 3990 | return ret; |
28b2ee20 RR |
3991 | } |
3992 | ||
3993 | int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, | |
3994 | void *buf, int len, int write) | |
3995 | { | |
3996 | resource_size_t phys_addr; | |
3997 | unsigned long prot = 0; | |
2bc7273b | 3998 | void __iomem *maddr; |
28b2ee20 RR |
3999 | int offset = addr & (PAGE_SIZE-1); |
4000 | ||
d87fe660 | 4001 | if (follow_phys(vma, addr, write, &prot, &phys_addr)) |
28b2ee20 RR |
4002 | return -EINVAL; |
4003 | ||
4004 | maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); | |
4005 | if (write) | |
4006 | memcpy_toio(maddr + offset, buf, len); | |
4007 | else | |
4008 | memcpy_fromio(buf, maddr + offset, len); | |
4009 | iounmap(maddr); | |
4010 | ||
4011 | return len; | |
4012 | } | |
4013 | #endif | |
4014 | ||
0ec76a11 | 4015 | /* |
206cb636 SW |
4016 | * Access another process' address space as given in mm. If non-NULL, use the |
4017 | * given task for page fault accounting. | |
0ec76a11 | 4018 | */ |
206cb636 SW |
4019 | static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, |
4020 | unsigned long addr, void *buf, int len, int write) | |
0ec76a11 | 4021 | { |
0ec76a11 | 4022 | struct vm_area_struct *vma; |
0ec76a11 DH |
4023 | void *old_buf = buf; |
4024 | ||
0ec76a11 | 4025 | down_read(&mm->mmap_sem); |
183ff22b | 4026 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
4027 | while (len) { |
4028 | int bytes, ret, offset; | |
4029 | void *maddr; | |
28b2ee20 | 4030 | struct page *page = NULL; |
0ec76a11 DH |
4031 | |
4032 | ret = get_user_pages(tsk, mm, addr, 1, | |
4033 | write, 1, &page, &vma); | |
28b2ee20 RR |
4034 | if (ret <= 0) { |
4035 | /* | |
4036 | * Check if this is a VM_IO | VM_PFNMAP VMA, which | |
4037 | * we can access using slightly different code. | |
4038 | */ | |
4039 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
4040 | vma = find_vma(mm, addr); | |
fe936dfc | 4041 | if (!vma || vma->vm_start > addr) |
28b2ee20 RR |
4042 | break; |
4043 | if (vma->vm_ops && vma->vm_ops->access) | |
4044 | ret = vma->vm_ops->access(vma, addr, buf, | |
4045 | len, write); | |
4046 | if (ret <= 0) | |
4047 | #endif | |
4048 | break; | |
4049 | bytes = ret; | |
0ec76a11 | 4050 | } else { |
28b2ee20 RR |
4051 | bytes = len; |
4052 | offset = addr & (PAGE_SIZE-1); | |
4053 | if (bytes > PAGE_SIZE-offset) | |
4054 | bytes = PAGE_SIZE-offset; | |
4055 | ||
4056 | maddr = kmap(page); | |
4057 | if (write) { | |
4058 | copy_to_user_page(vma, page, addr, | |
4059 | maddr + offset, buf, bytes); | |
4060 | set_page_dirty_lock(page); | |
4061 | } else { | |
4062 | copy_from_user_page(vma, page, addr, | |
4063 | buf, maddr + offset, bytes); | |
4064 | } | |
4065 | kunmap(page); | |
4066 | page_cache_release(page); | |
0ec76a11 | 4067 | } |
0ec76a11 DH |
4068 | len -= bytes; |
4069 | buf += bytes; | |
4070 | addr += bytes; | |
4071 | } | |
4072 | up_read(&mm->mmap_sem); | |
0ec76a11 DH |
4073 | |
4074 | return buf - old_buf; | |
4075 | } | |
03252919 | 4076 | |
5ddd36b9 | 4077 | /** |
ae91dbfc | 4078 | * access_remote_vm - access another process' address space |
5ddd36b9 SW |
4079 | * @mm: the mm_struct of the target address space |
4080 | * @addr: start address to access | |
4081 | * @buf: source or destination buffer | |
4082 | * @len: number of bytes to transfer | |
4083 | * @write: whether the access is a write | |
4084 | * | |
4085 | * The caller must hold a reference on @mm. | |
4086 | */ | |
4087 | int access_remote_vm(struct mm_struct *mm, unsigned long addr, | |
4088 | void *buf, int len, int write) | |
4089 | { | |
4090 | return __access_remote_vm(NULL, mm, addr, buf, len, write); | |
4091 | } | |
4092 | ||
206cb636 SW |
4093 | /* |
4094 | * Access another process' address space. | |
4095 | * Source/target buffer must be kernel space, | |
4096 | * Do not walk the page table directly, use get_user_pages | |
4097 | */ | |
4098 | int access_process_vm(struct task_struct *tsk, unsigned long addr, | |
4099 | void *buf, int len, int write) | |
4100 | { | |
4101 | struct mm_struct *mm; | |
4102 | int ret; | |
4103 | ||
4104 | mm = get_task_mm(tsk); | |
4105 | if (!mm) | |
4106 | return 0; | |
4107 | ||
4108 | ret = __access_remote_vm(tsk, mm, addr, buf, len, write); | |
4109 | mmput(mm); | |
4110 | ||
4111 | return ret; | |
4112 | } | |
4113 | ||
03252919 AK |
4114 | /* |
4115 | * Print the name of a VMA. | |
4116 | */ | |
4117 | void print_vma_addr(char *prefix, unsigned long ip) | |
4118 | { | |
4119 | struct mm_struct *mm = current->mm; | |
4120 | struct vm_area_struct *vma; | |
4121 | ||
e8bff74a IM |
4122 | /* |
4123 | * Do not print if we are in atomic | |
4124 | * contexts (in exception stacks, etc.): | |
4125 | */ | |
4126 | if (preempt_count()) | |
4127 | return; | |
4128 | ||
03252919 AK |
4129 | down_read(&mm->mmap_sem); |
4130 | vma = find_vma(mm, ip); | |
4131 | if (vma && vma->vm_file) { | |
4132 | struct file *f = vma->vm_file; | |
4133 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
4134 | if (buf) { | |
2fbc57c5 | 4135 | char *p; |
03252919 | 4136 | |
cf28b486 | 4137 | p = d_path(&f->f_path, buf, PAGE_SIZE); |
03252919 AK |
4138 | if (IS_ERR(p)) |
4139 | p = "?"; | |
2fbc57c5 | 4140 | printk("%s%s[%lx+%lx]", prefix, kbasename(p), |
03252919 AK |
4141 | vma->vm_start, |
4142 | vma->vm_end - vma->vm_start); | |
4143 | free_page((unsigned long)buf); | |
4144 | } | |
4145 | } | |
51a07e50 | 4146 | up_read(&mm->mmap_sem); |
03252919 | 4147 | } |
3ee1afa3 NP |
4148 | |
4149 | #ifdef CONFIG_PROVE_LOCKING | |
4150 | void might_fault(void) | |
4151 | { | |
95156f00 PZ |
4152 | /* |
4153 | * Some code (nfs/sunrpc) uses socket ops on kernel memory while | |
4154 | * holding the mmap_sem, this is safe because kernel memory doesn't | |
4155 | * get paged out, therefore we'll never actually fault, and the | |
4156 | * below annotations will generate false positives. | |
4157 | */ | |
4158 | if (segment_eq(get_fs(), KERNEL_DS)) | |
4159 | return; | |
4160 | ||
3ee1afa3 NP |
4161 | might_sleep(); |
4162 | /* | |
4163 | * it would be nicer only to annotate paths which are not under | |
4164 | * pagefault_disable, however that requires a larger audit and | |
4165 | * providing helpers like get_user_atomic. | |
4166 | */ | |
4167 | if (!in_atomic() && current->mm) | |
4168 | might_lock_read(¤t->mm->mmap_sem); | |
4169 | } | |
4170 | EXPORT_SYMBOL(might_fault); | |
4171 | #endif | |
47ad8475 AA |
4172 | |
4173 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) | |
4174 | static void clear_gigantic_page(struct page *page, | |
4175 | unsigned long addr, | |
4176 | unsigned int pages_per_huge_page) | |
4177 | { | |
4178 | int i; | |
4179 | struct page *p = page; | |
4180 | ||
4181 | might_sleep(); | |
4182 | for (i = 0; i < pages_per_huge_page; | |
4183 | i++, p = mem_map_next(p, page, i)) { | |
4184 | cond_resched(); | |
4185 | clear_user_highpage(p, addr + i * PAGE_SIZE); | |
4186 | } | |
4187 | } | |
4188 | void clear_huge_page(struct page *page, | |
4189 | unsigned long addr, unsigned int pages_per_huge_page) | |
4190 | { | |
4191 | int i; | |
4192 | ||
4193 | if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { | |
4194 | clear_gigantic_page(page, addr, pages_per_huge_page); | |
4195 | return; | |
4196 | } | |
4197 | ||
4198 | might_sleep(); | |
4199 | for (i = 0; i < pages_per_huge_page; i++) { | |
4200 | cond_resched(); | |
4201 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); | |
4202 | } | |
4203 | } | |
4204 | ||
4205 | static void copy_user_gigantic_page(struct page *dst, struct page *src, | |
4206 | unsigned long addr, | |
4207 | struct vm_area_struct *vma, | |
4208 | unsigned int pages_per_huge_page) | |
4209 | { | |
4210 | int i; | |
4211 | struct page *dst_base = dst; | |
4212 | struct page *src_base = src; | |
4213 | ||
4214 | for (i = 0; i < pages_per_huge_page; ) { | |
4215 | cond_resched(); | |
4216 | copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); | |
4217 | ||
4218 | i++; | |
4219 | dst = mem_map_next(dst, dst_base, i); | |
4220 | src = mem_map_next(src, src_base, i); | |
4221 | } | |
4222 | } | |
4223 | ||
4224 | void copy_user_huge_page(struct page *dst, struct page *src, | |
4225 | unsigned long addr, struct vm_area_struct *vma, | |
4226 | unsigned int pages_per_huge_page) | |
4227 | { | |
4228 | int i; | |
4229 | ||
4230 | if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { | |
4231 | copy_user_gigantic_page(dst, src, addr, vma, | |
4232 | pages_per_huge_page); | |
4233 | return; | |
4234 | } | |
4235 | ||
4236 | might_sleep(); | |
4237 | for (i = 0; i < pages_per_huge_page; i++) { | |
4238 | cond_resched(); | |
4239 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); | |
4240 | } | |
4241 | } | |
4242 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ |