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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 LT |
49 | #include <linux/rmap.h> |
50 | #include <linux/module.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> |
1da177e4 | 60 | |
6952b61d | 61 | #include <asm/io.h> |
1da177e4 LT |
62 | #include <asm/pgalloc.h> |
63 | #include <asm/uaccess.h> | |
64 | #include <asm/tlb.h> | |
65 | #include <asm/tlbflush.h> | |
66 | #include <asm/pgtable.h> | |
67 | ||
42b77728 JB |
68 | #include "internal.h" |
69 | ||
d41dee36 | 70 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
71 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
72 | unsigned long max_mapnr; | |
73 | struct page *mem_map; | |
74 | ||
75 | EXPORT_SYMBOL(max_mapnr); | |
76 | EXPORT_SYMBOL(mem_map); | |
77 | #endif | |
78 | ||
79 | unsigned long num_physpages; | |
80 | /* | |
81 | * A number of key systems in x86 including ioremap() rely on the assumption | |
82 | * that high_memory defines the upper bound on direct map memory, then end | |
83 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and | |
84 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL | |
85 | * and ZONE_HIGHMEM. | |
86 | */ | |
87 | void * high_memory; | |
1da177e4 LT |
88 | |
89 | EXPORT_SYMBOL(num_physpages); | |
90 | EXPORT_SYMBOL(high_memory); | |
1da177e4 | 91 | |
32a93233 IM |
92 | /* |
93 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
94 | * | |
95 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
96 | * as ancient (libc5 based) binaries can segfault. ) | |
97 | */ | |
98 | int randomize_va_space __read_mostly = | |
99 | #ifdef CONFIG_COMPAT_BRK | |
100 | 1; | |
101 | #else | |
102 | 2; | |
103 | #endif | |
a62eaf15 AK |
104 | |
105 | static int __init disable_randmaps(char *s) | |
106 | { | |
107 | randomize_va_space = 0; | |
9b41046c | 108 | return 1; |
a62eaf15 AK |
109 | } |
110 | __setup("norandmaps", disable_randmaps); | |
111 | ||
62eede62 | 112 | unsigned long zero_pfn __read_mostly; |
03f6462a | 113 | unsigned long highest_memmap_pfn __read_mostly; |
a13ea5b7 HD |
114 | |
115 | /* | |
116 | * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() | |
117 | */ | |
118 | static int __init init_zero_pfn(void) | |
119 | { | |
120 | zero_pfn = page_to_pfn(ZERO_PAGE(0)); | |
121 | return 0; | |
122 | } | |
123 | core_initcall(init_zero_pfn); | |
a62eaf15 | 124 | |
d559db08 | 125 | |
34e55232 KH |
126 | #if defined(SPLIT_RSS_COUNTING) |
127 | ||
a3a2e76c | 128 | static void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm) |
34e55232 KH |
129 | { |
130 | int i; | |
131 | ||
132 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
133 | if (task->rss_stat.count[i]) { | |
134 | add_mm_counter(mm, i, task->rss_stat.count[i]); | |
135 | task->rss_stat.count[i] = 0; | |
136 | } | |
137 | } | |
138 | task->rss_stat.events = 0; | |
139 | } | |
140 | ||
141 | static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) | |
142 | { | |
143 | struct task_struct *task = current; | |
144 | ||
145 | if (likely(task->mm == mm)) | |
146 | task->rss_stat.count[member] += val; | |
147 | else | |
148 | add_mm_counter(mm, member, val); | |
149 | } | |
150 | #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) | |
151 | #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) | |
152 | ||
153 | /* sync counter once per 64 page faults */ | |
154 | #define TASK_RSS_EVENTS_THRESH (64) | |
155 | static void check_sync_rss_stat(struct task_struct *task) | |
156 | { | |
157 | if (unlikely(task != current)) | |
158 | return; | |
159 | if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) | |
160 | __sync_task_rss_stat(task, task->mm); | |
161 | } | |
162 | ||
163 | unsigned long get_mm_counter(struct mm_struct *mm, int member) | |
164 | { | |
165 | long val = 0; | |
166 | ||
167 | /* | |
168 | * Don't use task->mm here...for avoiding to use task_get_mm().. | |
169 | * The caller must guarantee task->mm is not invalid. | |
170 | */ | |
171 | val = atomic_long_read(&mm->rss_stat.count[member]); | |
172 | /* | |
173 | * counter is updated in asynchronous manner and may go to minus. | |
174 | * But it's never be expected number for users. | |
175 | */ | |
176 | if (val < 0) | |
177 | return 0; | |
178 | return (unsigned long)val; | |
179 | } | |
180 | ||
181 | void sync_mm_rss(struct task_struct *task, struct mm_struct *mm) | |
182 | { | |
183 | __sync_task_rss_stat(task, mm); | |
184 | } | |
9547d01b | 185 | #else /* SPLIT_RSS_COUNTING */ |
34e55232 KH |
186 | |
187 | #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) | |
188 | #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) | |
189 | ||
190 | static void check_sync_rss_stat(struct task_struct *task) | |
191 | { | |
192 | } | |
193 | ||
9547d01b PZ |
194 | #endif /* SPLIT_RSS_COUNTING */ |
195 | ||
196 | #ifdef HAVE_GENERIC_MMU_GATHER | |
197 | ||
198 | static int tlb_next_batch(struct mmu_gather *tlb) | |
199 | { | |
200 | struct mmu_gather_batch *batch; | |
201 | ||
202 | batch = tlb->active; | |
203 | if (batch->next) { | |
204 | tlb->active = batch->next; | |
205 | return 1; | |
206 | } | |
207 | ||
208 | batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); | |
209 | if (!batch) | |
210 | return 0; | |
211 | ||
212 | batch->next = NULL; | |
213 | batch->nr = 0; | |
214 | batch->max = MAX_GATHER_BATCH; | |
215 | ||
216 | tlb->active->next = batch; | |
217 | tlb->active = batch; | |
218 | ||
219 | return 1; | |
220 | } | |
221 | ||
222 | /* tlb_gather_mmu | |
223 | * Called to initialize an (on-stack) mmu_gather structure for page-table | |
224 | * tear-down from @mm. The @fullmm argument is used when @mm is without | |
225 | * users and we're going to destroy the full address space (exit/execve). | |
226 | */ | |
227 | void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, bool fullmm) | |
228 | { | |
229 | tlb->mm = mm; | |
230 | ||
231 | tlb->fullmm = fullmm; | |
232 | tlb->need_flush = 0; | |
233 | tlb->fast_mode = (num_possible_cpus() == 1); | |
234 | tlb->local.next = NULL; | |
235 | tlb->local.nr = 0; | |
236 | tlb->local.max = ARRAY_SIZE(tlb->__pages); | |
237 | tlb->active = &tlb->local; | |
238 | ||
239 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE | |
240 | tlb->batch = NULL; | |
241 | #endif | |
242 | } | |
243 | ||
244 | void tlb_flush_mmu(struct mmu_gather *tlb) | |
245 | { | |
246 | struct mmu_gather_batch *batch; | |
247 | ||
248 | if (!tlb->need_flush) | |
249 | return; | |
250 | tlb->need_flush = 0; | |
251 | tlb_flush(tlb); | |
252 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE | |
253 | tlb_table_flush(tlb); | |
34e55232 KH |
254 | #endif |
255 | ||
9547d01b PZ |
256 | if (tlb_fast_mode(tlb)) |
257 | return; | |
258 | ||
259 | for (batch = &tlb->local; batch; batch = batch->next) { | |
260 | free_pages_and_swap_cache(batch->pages, batch->nr); | |
261 | batch->nr = 0; | |
262 | } | |
263 | tlb->active = &tlb->local; | |
264 | } | |
265 | ||
266 | /* tlb_finish_mmu | |
267 | * Called at the end of the shootdown operation to free up any resources | |
268 | * that were required. | |
269 | */ | |
270 | void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) | |
271 | { | |
272 | struct mmu_gather_batch *batch, *next; | |
273 | ||
274 | tlb_flush_mmu(tlb); | |
275 | ||
276 | /* keep the page table cache within bounds */ | |
277 | check_pgt_cache(); | |
278 | ||
279 | for (batch = tlb->local.next; batch; batch = next) { | |
280 | next = batch->next; | |
281 | free_pages((unsigned long)batch, 0); | |
282 | } | |
283 | tlb->local.next = NULL; | |
284 | } | |
285 | ||
286 | /* __tlb_remove_page | |
287 | * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while | |
288 | * handling the additional races in SMP caused by other CPUs caching valid | |
289 | * mappings in their TLBs. Returns the number of free page slots left. | |
290 | * When out of page slots we must call tlb_flush_mmu(). | |
291 | */ | |
292 | int __tlb_remove_page(struct mmu_gather *tlb, struct page *page) | |
293 | { | |
294 | struct mmu_gather_batch *batch; | |
295 | ||
296 | tlb->need_flush = 1; | |
297 | ||
298 | if (tlb_fast_mode(tlb)) { | |
299 | free_page_and_swap_cache(page); | |
300 | return 1; /* avoid calling tlb_flush_mmu() */ | |
301 | } | |
302 | ||
303 | batch = tlb->active; | |
304 | batch->pages[batch->nr++] = page; | |
305 | if (batch->nr == batch->max) { | |
306 | if (!tlb_next_batch(tlb)) | |
307 | return 0; | |
0b43c3aa | 308 | batch = tlb->active; |
9547d01b PZ |
309 | } |
310 | VM_BUG_ON(batch->nr > batch->max); | |
311 | ||
312 | return batch->max - batch->nr; | |
313 | } | |
314 | ||
315 | #endif /* HAVE_GENERIC_MMU_GATHER */ | |
316 | ||
26723911 PZ |
317 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE |
318 | ||
319 | /* | |
320 | * See the comment near struct mmu_table_batch. | |
321 | */ | |
322 | ||
323 | static void tlb_remove_table_smp_sync(void *arg) | |
324 | { | |
325 | /* Simply deliver the interrupt */ | |
326 | } | |
327 | ||
328 | static void tlb_remove_table_one(void *table) | |
329 | { | |
330 | /* | |
331 | * This isn't an RCU grace period and hence the page-tables cannot be | |
332 | * assumed to be actually RCU-freed. | |
333 | * | |
334 | * It is however sufficient for software page-table walkers that rely on | |
335 | * IRQ disabling. See the comment near struct mmu_table_batch. | |
336 | */ | |
337 | smp_call_function(tlb_remove_table_smp_sync, NULL, 1); | |
338 | __tlb_remove_table(table); | |
339 | } | |
340 | ||
341 | static void tlb_remove_table_rcu(struct rcu_head *head) | |
342 | { | |
343 | struct mmu_table_batch *batch; | |
344 | int i; | |
345 | ||
346 | batch = container_of(head, struct mmu_table_batch, rcu); | |
347 | ||
348 | for (i = 0; i < batch->nr; i++) | |
349 | __tlb_remove_table(batch->tables[i]); | |
350 | ||
351 | free_page((unsigned long)batch); | |
352 | } | |
353 | ||
354 | void tlb_table_flush(struct mmu_gather *tlb) | |
355 | { | |
356 | struct mmu_table_batch **batch = &tlb->batch; | |
357 | ||
358 | if (*batch) { | |
359 | call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); | |
360 | *batch = NULL; | |
361 | } | |
362 | } | |
363 | ||
364 | void tlb_remove_table(struct mmu_gather *tlb, void *table) | |
365 | { | |
366 | struct mmu_table_batch **batch = &tlb->batch; | |
367 | ||
368 | tlb->need_flush = 1; | |
369 | ||
370 | /* | |
371 | * When there's less then two users of this mm there cannot be a | |
372 | * concurrent page-table walk. | |
373 | */ | |
374 | if (atomic_read(&tlb->mm->mm_users) < 2) { | |
375 | __tlb_remove_table(table); | |
376 | return; | |
377 | } | |
378 | ||
379 | if (*batch == NULL) { | |
380 | *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); | |
381 | if (*batch == NULL) { | |
382 | tlb_remove_table_one(table); | |
383 | return; | |
384 | } | |
385 | (*batch)->nr = 0; | |
386 | } | |
387 | (*batch)->tables[(*batch)->nr++] = table; | |
388 | if ((*batch)->nr == MAX_TABLE_BATCH) | |
389 | tlb_table_flush(tlb); | |
390 | } | |
391 | ||
9547d01b | 392 | #endif /* CONFIG_HAVE_RCU_TABLE_FREE */ |
26723911 | 393 | |
1da177e4 LT |
394 | /* |
395 | * If a p?d_bad entry is found while walking page tables, report | |
396 | * the error, before resetting entry to p?d_none. Usually (but | |
397 | * very seldom) called out from the p?d_none_or_clear_bad macros. | |
398 | */ | |
399 | ||
400 | void pgd_clear_bad(pgd_t *pgd) | |
401 | { | |
402 | pgd_ERROR(*pgd); | |
403 | pgd_clear(pgd); | |
404 | } | |
405 | ||
406 | void pud_clear_bad(pud_t *pud) | |
407 | { | |
408 | pud_ERROR(*pud); | |
409 | pud_clear(pud); | |
410 | } | |
411 | ||
412 | void pmd_clear_bad(pmd_t *pmd) | |
413 | { | |
414 | pmd_ERROR(*pmd); | |
415 | pmd_clear(pmd); | |
416 | } | |
417 | ||
418 | /* | |
419 | * Note: this doesn't free the actual pages themselves. That | |
420 | * has been handled earlier when unmapping all the memory regions. | |
421 | */ | |
9e1b32ca BH |
422 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, |
423 | unsigned long addr) | |
1da177e4 | 424 | { |
2f569afd | 425 | pgtable_t token = pmd_pgtable(*pmd); |
e0da382c | 426 | pmd_clear(pmd); |
9e1b32ca | 427 | pte_free_tlb(tlb, token, addr); |
e0da382c | 428 | tlb->mm->nr_ptes--; |
1da177e4 LT |
429 | } |
430 | ||
e0da382c HD |
431 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
432 | unsigned long addr, unsigned long end, | |
433 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
434 | { |
435 | pmd_t *pmd; | |
436 | unsigned long next; | |
e0da382c | 437 | unsigned long start; |
1da177e4 | 438 | |
e0da382c | 439 | start = addr; |
1da177e4 | 440 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
441 | do { |
442 | next = pmd_addr_end(addr, end); | |
443 | if (pmd_none_or_clear_bad(pmd)) | |
444 | continue; | |
9e1b32ca | 445 | free_pte_range(tlb, pmd, addr); |
1da177e4 LT |
446 | } while (pmd++, addr = next, addr != end); |
447 | ||
e0da382c HD |
448 | start &= PUD_MASK; |
449 | if (start < floor) | |
450 | return; | |
451 | if (ceiling) { | |
452 | ceiling &= PUD_MASK; | |
453 | if (!ceiling) | |
454 | return; | |
1da177e4 | 455 | } |
e0da382c HD |
456 | if (end - 1 > ceiling - 1) |
457 | return; | |
458 | ||
459 | pmd = pmd_offset(pud, start); | |
460 | pud_clear(pud); | |
9e1b32ca | 461 | pmd_free_tlb(tlb, pmd, start); |
1da177e4 LT |
462 | } |
463 | ||
e0da382c HD |
464 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
465 | unsigned long addr, unsigned long end, | |
466 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
467 | { |
468 | pud_t *pud; | |
469 | unsigned long next; | |
e0da382c | 470 | unsigned long start; |
1da177e4 | 471 | |
e0da382c | 472 | start = addr; |
1da177e4 | 473 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
474 | do { |
475 | next = pud_addr_end(addr, end); | |
476 | if (pud_none_or_clear_bad(pud)) | |
477 | continue; | |
e0da382c | 478 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
479 | } while (pud++, addr = next, addr != end); |
480 | ||
e0da382c HD |
481 | start &= PGDIR_MASK; |
482 | if (start < floor) | |
483 | return; | |
484 | if (ceiling) { | |
485 | ceiling &= PGDIR_MASK; | |
486 | if (!ceiling) | |
487 | return; | |
1da177e4 | 488 | } |
e0da382c HD |
489 | if (end - 1 > ceiling - 1) |
490 | return; | |
491 | ||
492 | pud = pud_offset(pgd, start); | |
493 | pgd_clear(pgd); | |
9e1b32ca | 494 | pud_free_tlb(tlb, pud, start); |
1da177e4 LT |
495 | } |
496 | ||
497 | /* | |
e0da382c HD |
498 | * This function frees user-level page tables of a process. |
499 | * | |
1da177e4 LT |
500 | * Must be called with pagetable lock held. |
501 | */ | |
42b77728 | 502 | void free_pgd_range(struct mmu_gather *tlb, |
e0da382c HD |
503 | unsigned long addr, unsigned long end, |
504 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
505 | { |
506 | pgd_t *pgd; | |
507 | unsigned long next; | |
e0da382c HD |
508 | |
509 | /* | |
510 | * The next few lines have given us lots of grief... | |
511 | * | |
512 | * Why are we testing PMD* at this top level? Because often | |
513 | * there will be no work to do at all, and we'd prefer not to | |
514 | * go all the way down to the bottom just to discover that. | |
515 | * | |
516 | * Why all these "- 1"s? Because 0 represents both the bottom | |
517 | * of the address space and the top of it (using -1 for the | |
518 | * top wouldn't help much: the masks would do the wrong thing). | |
519 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
520 | * the address space, but end 0 and ceiling 0 refer to the top | |
521 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
522 | * that end 0 case should be mythical). | |
523 | * | |
524 | * Wherever addr is brought up or ceiling brought down, we must | |
525 | * be careful to reject "the opposite 0" before it confuses the | |
526 | * subsequent tests. But what about where end is brought down | |
527 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
528 | * | |
529 | * Whereas we round start (addr) and ceiling down, by different | |
530 | * masks at different levels, in order to test whether a table | |
531 | * now has no other vmas using it, so can be freed, we don't | |
532 | * bother to round floor or end up - the tests don't need that. | |
533 | */ | |
1da177e4 | 534 | |
e0da382c HD |
535 | addr &= PMD_MASK; |
536 | if (addr < floor) { | |
537 | addr += PMD_SIZE; | |
538 | if (!addr) | |
539 | return; | |
540 | } | |
541 | if (ceiling) { | |
542 | ceiling &= PMD_MASK; | |
543 | if (!ceiling) | |
544 | return; | |
545 | } | |
546 | if (end - 1 > ceiling - 1) | |
547 | end -= PMD_SIZE; | |
548 | if (addr > end - 1) | |
549 | return; | |
550 | ||
42b77728 | 551 | pgd = pgd_offset(tlb->mm, addr); |
1da177e4 LT |
552 | do { |
553 | next = pgd_addr_end(addr, end); | |
554 | if (pgd_none_or_clear_bad(pgd)) | |
555 | continue; | |
42b77728 | 556 | free_pud_range(tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 557 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
558 | } |
559 | ||
42b77728 | 560 | void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3bf5ee95 | 561 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
562 | { |
563 | while (vma) { | |
564 | struct vm_area_struct *next = vma->vm_next; | |
565 | unsigned long addr = vma->vm_start; | |
566 | ||
8f4f8c16 | 567 | /* |
25d9e2d1 | 568 | * Hide vma from rmap and truncate_pagecache before freeing |
569 | * pgtables | |
8f4f8c16 | 570 | */ |
5beb4930 | 571 | unlink_anon_vmas(vma); |
8f4f8c16 HD |
572 | unlink_file_vma(vma); |
573 | ||
9da61aef | 574 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 575 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 576 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
577 | } else { |
578 | /* | |
579 | * Optimization: gather nearby vmas into one call down | |
580 | */ | |
581 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 582 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
583 | vma = next; |
584 | next = vma->vm_next; | |
5beb4930 | 585 | unlink_anon_vmas(vma); |
8f4f8c16 | 586 | unlink_file_vma(vma); |
3bf5ee95 HD |
587 | } |
588 | free_pgd_range(tlb, addr, vma->vm_end, | |
589 | floor, next? next->vm_start: ceiling); | |
590 | } | |
e0da382c HD |
591 | vma = next; |
592 | } | |
1da177e4 LT |
593 | } |
594 | ||
8ac1f832 AA |
595 | int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, |
596 | pmd_t *pmd, unsigned long address) | |
1da177e4 | 597 | { |
2f569afd | 598 | pgtable_t new = pte_alloc_one(mm, address); |
8ac1f832 | 599 | int wait_split_huge_page; |
1bb3630e HD |
600 | if (!new) |
601 | return -ENOMEM; | |
602 | ||
362a61ad NP |
603 | /* |
604 | * Ensure all pte setup (eg. pte page lock and page clearing) are | |
605 | * visible before the pte is made visible to other CPUs by being | |
606 | * put into page tables. | |
607 | * | |
608 | * The other side of the story is the pointer chasing in the page | |
609 | * table walking code (when walking the page table without locking; | |
610 | * ie. most of the time). Fortunately, these data accesses consist | |
611 | * of a chain of data-dependent loads, meaning most CPUs (alpha | |
612 | * being the notable exception) will already guarantee loads are | |
613 | * seen in-order. See the alpha page table accessors for the | |
614 | * smp_read_barrier_depends() barriers in page table walking code. | |
615 | */ | |
616 | smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ | |
617 | ||
c74df32c | 618 | spin_lock(&mm->page_table_lock); |
8ac1f832 AA |
619 | wait_split_huge_page = 0; |
620 | if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ | |
1da177e4 | 621 | mm->nr_ptes++; |
1da177e4 | 622 | pmd_populate(mm, pmd, new); |
2f569afd | 623 | new = NULL; |
8ac1f832 AA |
624 | } else if (unlikely(pmd_trans_splitting(*pmd))) |
625 | wait_split_huge_page = 1; | |
c74df32c | 626 | spin_unlock(&mm->page_table_lock); |
2f569afd MS |
627 | if (new) |
628 | pte_free(mm, new); | |
8ac1f832 AA |
629 | if (wait_split_huge_page) |
630 | wait_split_huge_page(vma->anon_vma, pmd); | |
1bb3630e | 631 | return 0; |
1da177e4 LT |
632 | } |
633 | ||
1bb3630e | 634 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 635 | { |
1bb3630e HD |
636 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
637 | if (!new) | |
638 | return -ENOMEM; | |
639 | ||
362a61ad NP |
640 | smp_wmb(); /* See comment in __pte_alloc */ |
641 | ||
1bb3630e | 642 | spin_lock(&init_mm.page_table_lock); |
8ac1f832 | 643 | if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ |
1bb3630e | 644 | pmd_populate_kernel(&init_mm, pmd, new); |
2f569afd | 645 | new = NULL; |
8ac1f832 AA |
646 | } else |
647 | VM_BUG_ON(pmd_trans_splitting(*pmd)); | |
1bb3630e | 648 | spin_unlock(&init_mm.page_table_lock); |
2f569afd MS |
649 | if (new) |
650 | pte_free_kernel(&init_mm, new); | |
1bb3630e | 651 | return 0; |
1da177e4 LT |
652 | } |
653 | ||
d559db08 KH |
654 | static inline void init_rss_vec(int *rss) |
655 | { | |
656 | memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); | |
657 | } | |
658 | ||
659 | static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) | |
ae859762 | 660 | { |
d559db08 KH |
661 | int i; |
662 | ||
34e55232 KH |
663 | if (current->mm == mm) |
664 | sync_mm_rss(current, mm); | |
d559db08 KH |
665 | for (i = 0; i < NR_MM_COUNTERS; i++) |
666 | if (rss[i]) | |
667 | add_mm_counter(mm, i, rss[i]); | |
ae859762 HD |
668 | } |
669 | ||
b5810039 | 670 | /* |
6aab341e LT |
671 | * This function is called to print an error when a bad pte |
672 | * is found. For example, we might have a PFN-mapped pte in | |
673 | * a region that doesn't allow it. | |
b5810039 NP |
674 | * |
675 | * The calling function must still handle the error. | |
676 | */ | |
3dc14741 HD |
677 | static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, |
678 | pte_t pte, struct page *page) | |
b5810039 | 679 | { |
3dc14741 HD |
680 | pgd_t *pgd = pgd_offset(vma->vm_mm, addr); |
681 | pud_t *pud = pud_offset(pgd, addr); | |
682 | pmd_t *pmd = pmd_offset(pud, addr); | |
683 | struct address_space *mapping; | |
684 | pgoff_t index; | |
d936cf9b HD |
685 | static unsigned long resume; |
686 | static unsigned long nr_shown; | |
687 | static unsigned long nr_unshown; | |
688 | ||
689 | /* | |
690 | * Allow a burst of 60 reports, then keep quiet for that minute; | |
691 | * or allow a steady drip of one report per second. | |
692 | */ | |
693 | if (nr_shown == 60) { | |
694 | if (time_before(jiffies, resume)) { | |
695 | nr_unshown++; | |
696 | return; | |
697 | } | |
698 | if (nr_unshown) { | |
1e9e6365 HD |
699 | printk(KERN_ALERT |
700 | "BUG: Bad page map: %lu messages suppressed\n", | |
d936cf9b HD |
701 | nr_unshown); |
702 | nr_unshown = 0; | |
703 | } | |
704 | nr_shown = 0; | |
705 | } | |
706 | if (nr_shown++ == 0) | |
707 | resume = jiffies + 60 * HZ; | |
3dc14741 HD |
708 | |
709 | mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; | |
710 | index = linear_page_index(vma, addr); | |
711 | ||
1e9e6365 HD |
712 | printk(KERN_ALERT |
713 | "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", | |
3dc14741 HD |
714 | current->comm, |
715 | (long long)pte_val(pte), (long long)pmd_val(*pmd)); | |
718a3821 WF |
716 | if (page) |
717 | dump_page(page); | |
1e9e6365 | 718 | printk(KERN_ALERT |
3dc14741 HD |
719 | "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", |
720 | (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); | |
721 | /* | |
722 | * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y | |
723 | */ | |
724 | if (vma->vm_ops) | |
1e9e6365 | 725 | print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n", |
3dc14741 HD |
726 | (unsigned long)vma->vm_ops->fault); |
727 | if (vma->vm_file && vma->vm_file->f_op) | |
1e9e6365 | 728 | print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n", |
3dc14741 | 729 | (unsigned long)vma->vm_file->f_op->mmap); |
b5810039 | 730 | dump_stack(); |
3dc14741 | 731 | add_taint(TAINT_BAD_PAGE); |
b5810039 NP |
732 | } |
733 | ||
ca16d140 | 734 | static inline int is_cow_mapping(vm_flags_t flags) |
67121172 LT |
735 | { |
736 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
737 | } | |
738 | ||
62eede62 HD |
739 | #ifndef is_zero_pfn |
740 | static inline int is_zero_pfn(unsigned long pfn) | |
741 | { | |
742 | return pfn == zero_pfn; | |
743 | } | |
744 | #endif | |
745 | ||
746 | #ifndef my_zero_pfn | |
747 | static inline unsigned long my_zero_pfn(unsigned long addr) | |
748 | { | |
749 | return zero_pfn; | |
750 | } | |
751 | #endif | |
752 | ||
ee498ed7 | 753 | /* |
7e675137 | 754 | * vm_normal_page -- This function gets the "struct page" associated with a pte. |
6aab341e | 755 | * |
7e675137 NP |
756 | * "Special" mappings do not wish to be associated with a "struct page" (either |
757 | * it doesn't exist, or it exists but they don't want to touch it). In this | |
758 | * case, NULL is returned here. "Normal" mappings do have a struct page. | |
b379d790 | 759 | * |
7e675137 NP |
760 | * There are 2 broad cases. Firstly, an architecture may define a pte_special() |
761 | * pte bit, in which case this function is trivial. Secondly, an architecture | |
762 | * may not have a spare pte bit, which requires a more complicated scheme, | |
763 | * described below. | |
764 | * | |
765 | * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a | |
766 | * special mapping (even if there are underlying and valid "struct pages"). | |
767 | * COWed pages of a VM_PFNMAP are always normal. | |
6aab341e | 768 | * |
b379d790 JH |
769 | * The way we recognize COWed pages within VM_PFNMAP mappings is through the |
770 | * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit | |
7e675137 NP |
771 | * set, and the vm_pgoff will point to the first PFN mapped: thus every special |
772 | * mapping will always honor the rule | |
6aab341e LT |
773 | * |
774 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
775 | * | |
7e675137 NP |
776 | * And for normal mappings this is false. |
777 | * | |
778 | * This restricts such mappings to be a linear translation from virtual address | |
779 | * to pfn. To get around this restriction, we allow arbitrary mappings so long | |
780 | * as the vma is not a COW mapping; in that case, we know that all ptes are | |
781 | * special (because none can have been COWed). | |
b379d790 | 782 | * |
b379d790 | 783 | * |
7e675137 | 784 | * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. |
b379d790 JH |
785 | * |
786 | * VM_MIXEDMAP mappings can likewise contain memory with or without "struct | |
787 | * page" backing, however the difference is that _all_ pages with a struct | |
788 | * page (that is, those where pfn_valid is true) are refcounted and considered | |
789 | * normal pages by the VM. The disadvantage is that pages are refcounted | |
790 | * (which can be slower and simply not an option for some PFNMAP users). The | |
791 | * advantage is that we don't have to follow the strict linearity rule of | |
792 | * PFNMAP mappings in order to support COWable mappings. | |
793 | * | |
ee498ed7 | 794 | */ |
7e675137 NP |
795 | #ifdef __HAVE_ARCH_PTE_SPECIAL |
796 | # define HAVE_PTE_SPECIAL 1 | |
797 | #else | |
798 | # define HAVE_PTE_SPECIAL 0 | |
799 | #endif | |
800 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, | |
801 | pte_t pte) | |
ee498ed7 | 802 | { |
22b31eec | 803 | unsigned long pfn = pte_pfn(pte); |
7e675137 NP |
804 | |
805 | if (HAVE_PTE_SPECIAL) { | |
22b31eec HD |
806 | if (likely(!pte_special(pte))) |
807 | goto check_pfn; | |
a13ea5b7 HD |
808 | if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) |
809 | return NULL; | |
62eede62 | 810 | if (!is_zero_pfn(pfn)) |
22b31eec | 811 | print_bad_pte(vma, addr, pte, NULL); |
7e675137 NP |
812 | return NULL; |
813 | } | |
814 | ||
815 | /* !HAVE_PTE_SPECIAL case follows: */ | |
816 | ||
b379d790 JH |
817 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { |
818 | if (vma->vm_flags & VM_MIXEDMAP) { | |
819 | if (!pfn_valid(pfn)) | |
820 | return NULL; | |
821 | goto out; | |
822 | } else { | |
7e675137 NP |
823 | unsigned long off; |
824 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
b379d790 JH |
825 | if (pfn == vma->vm_pgoff + off) |
826 | return NULL; | |
827 | if (!is_cow_mapping(vma->vm_flags)) | |
828 | return NULL; | |
829 | } | |
6aab341e LT |
830 | } |
831 | ||
62eede62 HD |
832 | if (is_zero_pfn(pfn)) |
833 | return NULL; | |
22b31eec HD |
834 | check_pfn: |
835 | if (unlikely(pfn > highest_memmap_pfn)) { | |
836 | print_bad_pte(vma, addr, pte, NULL); | |
837 | return NULL; | |
838 | } | |
6aab341e LT |
839 | |
840 | /* | |
7e675137 | 841 | * NOTE! We still have PageReserved() pages in the page tables. |
7e675137 | 842 | * eg. VDSO mappings can cause them to exist. |
6aab341e | 843 | */ |
b379d790 | 844 | out: |
6aab341e | 845 | return pfn_to_page(pfn); |
ee498ed7 HD |
846 | } |
847 | ||
1da177e4 LT |
848 | /* |
849 | * copy one vm_area from one task to the other. Assumes the page tables | |
850 | * already present in the new task to be cleared in the whole range | |
851 | * covered by this vma. | |
1da177e4 LT |
852 | */ |
853 | ||
570a335b | 854 | static inline unsigned long |
1da177e4 | 855 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 856 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 857 | unsigned long addr, int *rss) |
1da177e4 | 858 | { |
b5810039 | 859 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
860 | pte_t pte = *src_pte; |
861 | struct page *page; | |
1da177e4 LT |
862 | |
863 | /* pte contains position in swap or file, so copy. */ | |
864 | if (unlikely(!pte_present(pte))) { | |
865 | if (!pte_file(pte)) { | |
0697212a CL |
866 | swp_entry_t entry = pte_to_swp_entry(pte); |
867 | ||
570a335b HD |
868 | if (swap_duplicate(entry) < 0) |
869 | return entry.val; | |
870 | ||
1da177e4 LT |
871 | /* make sure dst_mm is on swapoff's mmlist. */ |
872 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
873 | spin_lock(&mmlist_lock); | |
f412ac08 HD |
874 | if (list_empty(&dst_mm->mmlist)) |
875 | list_add(&dst_mm->mmlist, | |
876 | &src_mm->mmlist); | |
1da177e4 LT |
877 | spin_unlock(&mmlist_lock); |
878 | } | |
b084d435 KH |
879 | if (likely(!non_swap_entry(entry))) |
880 | rss[MM_SWAPENTS]++; | |
881 | else if (is_write_migration_entry(entry) && | |
0697212a CL |
882 | is_cow_mapping(vm_flags)) { |
883 | /* | |
884 | * COW mappings require pages in both parent | |
885 | * and child to be set to read. | |
886 | */ | |
887 | make_migration_entry_read(&entry); | |
888 | pte = swp_entry_to_pte(entry); | |
889 | set_pte_at(src_mm, addr, src_pte, pte); | |
890 | } | |
1da177e4 | 891 | } |
ae859762 | 892 | goto out_set_pte; |
1da177e4 LT |
893 | } |
894 | ||
1da177e4 LT |
895 | /* |
896 | * If it's a COW mapping, write protect it both | |
897 | * in the parent and the child | |
898 | */ | |
67121172 | 899 | if (is_cow_mapping(vm_flags)) { |
1da177e4 | 900 | ptep_set_wrprotect(src_mm, addr, src_pte); |
3dc90795 | 901 | pte = pte_wrprotect(pte); |
1da177e4 LT |
902 | } |
903 | ||
904 | /* | |
905 | * If it's a shared mapping, mark it clean in | |
906 | * the child | |
907 | */ | |
908 | if (vm_flags & VM_SHARED) | |
909 | pte = pte_mkclean(pte); | |
910 | pte = pte_mkold(pte); | |
6aab341e LT |
911 | |
912 | page = vm_normal_page(vma, addr, pte); | |
913 | if (page) { | |
914 | get_page(page); | |
21333b2b | 915 | page_dup_rmap(page); |
d559db08 KH |
916 | if (PageAnon(page)) |
917 | rss[MM_ANONPAGES]++; | |
918 | else | |
919 | rss[MM_FILEPAGES]++; | |
6aab341e | 920 | } |
ae859762 HD |
921 | |
922 | out_set_pte: | |
923 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
570a335b | 924 | return 0; |
1da177e4 LT |
925 | } |
926 | ||
71e3aac0 AA |
927 | int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
928 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, | |
929 | unsigned long addr, unsigned long end) | |
1da177e4 | 930 | { |
c36987e2 | 931 | pte_t *orig_src_pte, *orig_dst_pte; |
1da177e4 | 932 | pte_t *src_pte, *dst_pte; |
c74df32c | 933 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 934 | int progress = 0; |
d559db08 | 935 | int rss[NR_MM_COUNTERS]; |
570a335b | 936 | swp_entry_t entry = (swp_entry_t){0}; |
1da177e4 LT |
937 | |
938 | again: | |
d559db08 KH |
939 | init_rss_vec(rss); |
940 | ||
c74df32c | 941 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
942 | if (!dst_pte) |
943 | return -ENOMEM; | |
ece0e2b6 | 944 | src_pte = pte_offset_map(src_pmd, addr); |
4c21e2f2 | 945 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 946 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
c36987e2 DN |
947 | orig_src_pte = src_pte; |
948 | orig_dst_pte = dst_pte; | |
6606c3e0 | 949 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 950 | |
1da177e4 LT |
951 | do { |
952 | /* | |
953 | * We are holding two locks at this point - either of them | |
954 | * could generate latencies in another task on another CPU. | |
955 | */ | |
e040f218 HD |
956 | if (progress >= 32) { |
957 | progress = 0; | |
958 | if (need_resched() || | |
95c354fe | 959 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
960 | break; |
961 | } | |
1da177e4 LT |
962 | if (pte_none(*src_pte)) { |
963 | progress++; | |
964 | continue; | |
965 | } | |
570a335b HD |
966 | entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, |
967 | vma, addr, rss); | |
968 | if (entry.val) | |
969 | break; | |
1da177e4 LT |
970 | progress += 8; |
971 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 972 | |
6606c3e0 | 973 | arch_leave_lazy_mmu_mode(); |
c74df32c | 974 | spin_unlock(src_ptl); |
ece0e2b6 | 975 | pte_unmap(orig_src_pte); |
d559db08 | 976 | add_mm_rss_vec(dst_mm, rss); |
c36987e2 | 977 | pte_unmap_unlock(orig_dst_pte, dst_ptl); |
c74df32c | 978 | cond_resched(); |
570a335b HD |
979 | |
980 | if (entry.val) { | |
981 | if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) | |
982 | return -ENOMEM; | |
983 | progress = 0; | |
984 | } | |
1da177e4 LT |
985 | if (addr != end) |
986 | goto again; | |
987 | return 0; | |
988 | } | |
989 | ||
990 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
991 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
992 | unsigned long addr, unsigned long end) | |
993 | { | |
994 | pmd_t *src_pmd, *dst_pmd; | |
995 | unsigned long next; | |
996 | ||
997 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
998 | if (!dst_pmd) | |
999 | return -ENOMEM; | |
1000 | src_pmd = pmd_offset(src_pud, addr); | |
1001 | do { | |
1002 | next = pmd_addr_end(addr, end); | |
71e3aac0 AA |
1003 | if (pmd_trans_huge(*src_pmd)) { |
1004 | int err; | |
14d1a55c | 1005 | VM_BUG_ON(next-addr != HPAGE_PMD_SIZE); |
71e3aac0 AA |
1006 | err = copy_huge_pmd(dst_mm, src_mm, |
1007 | dst_pmd, src_pmd, addr, vma); | |
1008 | if (err == -ENOMEM) | |
1009 | return -ENOMEM; | |
1010 | if (!err) | |
1011 | continue; | |
1012 | /* fall through */ | |
1013 | } | |
1da177e4 LT |
1014 | if (pmd_none_or_clear_bad(src_pmd)) |
1015 | continue; | |
1016 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
1017 | vma, addr, next)) | |
1018 | return -ENOMEM; | |
1019 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
1020 | return 0; | |
1021 | } | |
1022 | ||
1023 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1024 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
1025 | unsigned long addr, unsigned long end) | |
1026 | { | |
1027 | pud_t *src_pud, *dst_pud; | |
1028 | unsigned long next; | |
1029 | ||
1030 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
1031 | if (!dst_pud) | |
1032 | return -ENOMEM; | |
1033 | src_pud = pud_offset(src_pgd, addr); | |
1034 | do { | |
1035 | next = pud_addr_end(addr, end); | |
1036 | if (pud_none_or_clear_bad(src_pud)) | |
1037 | continue; | |
1038 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
1039 | vma, addr, next)) | |
1040 | return -ENOMEM; | |
1041 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
1042 | return 0; | |
1043 | } | |
1044 | ||
1045 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1046 | struct vm_area_struct *vma) | |
1047 | { | |
1048 | pgd_t *src_pgd, *dst_pgd; | |
1049 | unsigned long next; | |
1050 | unsigned long addr = vma->vm_start; | |
1051 | unsigned long end = vma->vm_end; | |
cddb8a5c | 1052 | int ret; |
1da177e4 | 1053 | |
d992895b NP |
1054 | /* |
1055 | * Don't copy ptes where a page fault will fill them correctly. | |
1056 | * Fork becomes much lighter when there are big shared or private | |
1057 | * readonly mappings. The tradeoff is that copy_page_range is more | |
1058 | * efficient than faulting. | |
1059 | */ | |
4d7672b4 | 1060 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { |
d992895b NP |
1061 | if (!vma->anon_vma) |
1062 | return 0; | |
1063 | } | |
1064 | ||
1da177e4 LT |
1065 | if (is_vm_hugetlb_page(vma)) |
1066 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
1067 | ||
34801ba9 | 1068 | if (unlikely(is_pfn_mapping(vma))) { |
2ab64037 | 1069 | /* |
1070 | * We do not free on error cases below as remove_vma | |
1071 | * gets called on error from higher level routine | |
1072 | */ | |
1073 | ret = track_pfn_vma_copy(vma); | |
1074 | if (ret) | |
1075 | return ret; | |
1076 | } | |
1077 | ||
cddb8a5c AA |
1078 | /* |
1079 | * We need to invalidate the secondary MMU mappings only when | |
1080 | * there could be a permission downgrade on the ptes of the | |
1081 | * parent mm. And a permission downgrade will only happen if | |
1082 | * is_cow_mapping() returns true. | |
1083 | */ | |
1084 | if (is_cow_mapping(vma->vm_flags)) | |
1085 | mmu_notifier_invalidate_range_start(src_mm, addr, end); | |
1086 | ||
1087 | ret = 0; | |
1da177e4 LT |
1088 | dst_pgd = pgd_offset(dst_mm, addr); |
1089 | src_pgd = pgd_offset(src_mm, addr); | |
1090 | do { | |
1091 | next = pgd_addr_end(addr, end); | |
1092 | if (pgd_none_or_clear_bad(src_pgd)) | |
1093 | continue; | |
cddb8a5c AA |
1094 | if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
1095 | vma, addr, next))) { | |
1096 | ret = -ENOMEM; | |
1097 | break; | |
1098 | } | |
1da177e4 | 1099 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
cddb8a5c AA |
1100 | |
1101 | if (is_cow_mapping(vma->vm_flags)) | |
1102 | mmu_notifier_invalidate_range_end(src_mm, | |
1103 | vma->vm_start, end); | |
1104 | return ret; | |
1da177e4 LT |
1105 | } |
1106 | ||
51c6f666 | 1107 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 1108 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 1109 | unsigned long addr, unsigned long end, |
97a89413 | 1110 | struct zap_details *details) |
1da177e4 | 1111 | { |
b5810039 | 1112 | struct mm_struct *mm = tlb->mm; |
d16dfc55 | 1113 | int force_flush = 0; |
d559db08 | 1114 | int rss[NR_MM_COUNTERS]; |
97a89413 | 1115 | spinlock_t *ptl; |
5f1a1907 | 1116 | pte_t *start_pte; |
97a89413 | 1117 | pte_t *pte; |
d559db08 | 1118 | |
d16dfc55 | 1119 | again: |
e303297e | 1120 | init_rss_vec(rss); |
5f1a1907 SR |
1121 | start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
1122 | pte = start_pte; | |
6606c3e0 | 1123 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1124 | do { |
1125 | pte_t ptent = *pte; | |
51c6f666 | 1126 | if (pte_none(ptent)) { |
1da177e4 | 1127 | continue; |
51c6f666 | 1128 | } |
6f5e6b9e | 1129 | |
1da177e4 | 1130 | if (pte_present(ptent)) { |
ee498ed7 | 1131 | struct page *page; |
51c6f666 | 1132 | |
6aab341e | 1133 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
1134 | if (unlikely(details) && page) { |
1135 | /* | |
1136 | * unmap_shared_mapping_pages() wants to | |
1137 | * invalidate cache without truncating: | |
1138 | * unmap shared but keep private pages. | |
1139 | */ | |
1140 | if (details->check_mapping && | |
1141 | details->check_mapping != page->mapping) | |
1142 | continue; | |
1143 | /* | |
1144 | * Each page->index must be checked when | |
1145 | * invalidating or truncating nonlinear. | |
1146 | */ | |
1147 | if (details->nonlinear_vma && | |
1148 | (page->index < details->first_index || | |
1149 | page->index > details->last_index)) | |
1150 | continue; | |
1151 | } | |
b5810039 | 1152 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 1153 | tlb->fullmm); |
1da177e4 LT |
1154 | tlb_remove_tlb_entry(tlb, pte, addr); |
1155 | if (unlikely(!page)) | |
1156 | continue; | |
1157 | if (unlikely(details) && details->nonlinear_vma | |
1158 | && linear_page_index(details->nonlinear_vma, | |
1159 | addr) != page->index) | |
b5810039 | 1160 | set_pte_at(mm, addr, pte, |
1da177e4 | 1161 | pgoff_to_pte(page->index)); |
1da177e4 | 1162 | if (PageAnon(page)) |
d559db08 | 1163 | rss[MM_ANONPAGES]--; |
6237bcd9 HD |
1164 | else { |
1165 | if (pte_dirty(ptent)) | |
1166 | set_page_dirty(page); | |
4917e5d0 JW |
1167 | if (pte_young(ptent) && |
1168 | likely(!VM_SequentialReadHint(vma))) | |
bf3f3bc5 | 1169 | mark_page_accessed(page); |
d559db08 | 1170 | rss[MM_FILEPAGES]--; |
6237bcd9 | 1171 | } |
edc315fd | 1172 | page_remove_rmap(page); |
3dc14741 HD |
1173 | if (unlikely(page_mapcount(page) < 0)) |
1174 | print_bad_pte(vma, addr, ptent, page); | |
d16dfc55 PZ |
1175 | force_flush = !__tlb_remove_page(tlb, page); |
1176 | if (force_flush) | |
1177 | break; | |
1da177e4 LT |
1178 | continue; |
1179 | } | |
1180 | /* | |
1181 | * If details->check_mapping, we leave swap entries; | |
1182 | * if details->nonlinear_vma, we leave file entries. | |
1183 | */ | |
1184 | if (unlikely(details)) | |
1185 | continue; | |
2509ef26 HD |
1186 | if (pte_file(ptent)) { |
1187 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) | |
1188 | print_bad_pte(vma, addr, ptent, NULL); | |
b084d435 KH |
1189 | } else { |
1190 | swp_entry_t entry = pte_to_swp_entry(ptent); | |
1191 | ||
1192 | if (!non_swap_entry(entry)) | |
1193 | rss[MM_SWAPENTS]--; | |
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; | |
1211 | tlb_flush_mmu(tlb); | |
1212 | if (addr != end) | |
1213 | goto again; | |
1214 | } | |
1215 | ||
51c6f666 | 1216 | return addr; |
1da177e4 LT |
1217 | } |
1218 | ||
51c6f666 | 1219 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 1220 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 1221 | unsigned long addr, unsigned long end, |
97a89413 | 1222 | struct zap_details *details) |
1da177e4 LT |
1223 | { |
1224 | pmd_t *pmd; | |
1225 | unsigned long next; | |
1226 | ||
1227 | pmd = pmd_offset(pud, addr); | |
1228 | do { | |
1229 | next = pmd_addr_end(addr, end); | |
71e3aac0 | 1230 | if (pmd_trans_huge(*pmd)) { |
14d1a55c AA |
1231 | if (next-addr != HPAGE_PMD_SIZE) { |
1232 | VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem)); | |
71e3aac0 | 1233 | split_huge_page_pmd(vma->vm_mm, pmd); |
97a89413 | 1234 | } else if (zap_huge_pmd(tlb, vma, pmd)) |
71e3aac0 | 1235 | continue; |
71e3aac0 AA |
1236 | /* fall through */ |
1237 | } | |
97a89413 | 1238 | if (pmd_none_or_clear_bad(pmd)) |
1da177e4 | 1239 | continue; |
97a89413 PZ |
1240 | next = zap_pte_range(tlb, vma, pmd, addr, next, details); |
1241 | cond_resched(); | |
1242 | } while (pmd++, addr = next, addr != end); | |
51c6f666 RH |
1243 | |
1244 | return addr; | |
1da177e4 LT |
1245 | } |
1246 | ||
51c6f666 | 1247 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 1248 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 1249 | unsigned long addr, unsigned long end, |
97a89413 | 1250 | struct zap_details *details) |
1da177e4 LT |
1251 | { |
1252 | pud_t *pud; | |
1253 | unsigned long next; | |
1254 | ||
1255 | pud = pud_offset(pgd, addr); | |
1256 | do { | |
1257 | next = pud_addr_end(addr, end); | |
97a89413 | 1258 | if (pud_none_or_clear_bad(pud)) |
1da177e4 | 1259 | continue; |
97a89413 PZ |
1260 | next = zap_pmd_range(tlb, vma, pud, addr, next, details); |
1261 | } while (pud++, addr = next, addr != end); | |
51c6f666 RH |
1262 | |
1263 | return addr; | |
1da177e4 LT |
1264 | } |
1265 | ||
51c6f666 RH |
1266 | static unsigned long unmap_page_range(struct mmu_gather *tlb, |
1267 | struct vm_area_struct *vma, | |
1da177e4 | 1268 | unsigned long addr, unsigned long end, |
97a89413 | 1269 | struct zap_details *details) |
1da177e4 LT |
1270 | { |
1271 | pgd_t *pgd; | |
1272 | unsigned long next; | |
1273 | ||
1274 | if (details && !details->check_mapping && !details->nonlinear_vma) | |
1275 | details = NULL; | |
1276 | ||
1277 | BUG_ON(addr >= end); | |
569b846d | 1278 | mem_cgroup_uncharge_start(); |
1da177e4 LT |
1279 | tlb_start_vma(tlb, vma); |
1280 | pgd = pgd_offset(vma->vm_mm, addr); | |
1281 | do { | |
1282 | next = pgd_addr_end(addr, end); | |
97a89413 | 1283 | if (pgd_none_or_clear_bad(pgd)) |
1da177e4 | 1284 | continue; |
97a89413 PZ |
1285 | next = zap_pud_range(tlb, vma, pgd, addr, next, details); |
1286 | } while (pgd++, addr = next, addr != end); | |
1da177e4 | 1287 | tlb_end_vma(tlb, vma); |
569b846d | 1288 | mem_cgroup_uncharge_end(); |
51c6f666 RH |
1289 | |
1290 | return addr; | |
1da177e4 LT |
1291 | } |
1292 | ||
1da177e4 LT |
1293 | /** |
1294 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
0164f69d | 1295 | * @tlb: address of the caller's struct mmu_gather |
1da177e4 LT |
1296 | * @vma: the starting vma |
1297 | * @start_addr: virtual address at which to start unmapping | |
1298 | * @end_addr: virtual address at which to end unmapping | |
1299 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here | |
1300 | * @details: details of nonlinear truncation or shared cache invalidation | |
1301 | * | |
ee39b37b | 1302 | * Returns the end address of the unmapping (restart addr if interrupted). |
1da177e4 | 1303 | * |
508034a3 | 1304 | * Unmap all pages in the vma list. |
1da177e4 | 1305 | * |
1da177e4 LT |
1306 | * Only addresses between `start' and `end' will be unmapped. |
1307 | * | |
1308 | * The VMA list must be sorted in ascending virtual address order. | |
1309 | * | |
1310 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
1311 | * range after unmap_vmas() returns. So the only responsibility here is to | |
1312 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
1313 | * drops the lock and schedules. | |
1314 | */ | |
d16dfc55 | 1315 | unsigned long unmap_vmas(struct mmu_gather *tlb, |
1da177e4 LT |
1316 | struct vm_area_struct *vma, unsigned long start_addr, |
1317 | unsigned long end_addr, unsigned long *nr_accounted, | |
1318 | struct zap_details *details) | |
1319 | { | |
ee39b37b | 1320 | unsigned long start = start_addr; |
cddb8a5c | 1321 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1322 | |
cddb8a5c | 1323 | mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); |
1da177e4 | 1324 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { |
1da177e4 LT |
1325 | unsigned long end; |
1326 | ||
1327 | start = max(vma->vm_start, start_addr); | |
1328 | if (start >= vma->vm_end) | |
1329 | continue; | |
1330 | end = min(vma->vm_end, end_addr); | |
1331 | if (end <= vma->vm_start) | |
1332 | continue; | |
1333 | ||
1334 | if (vma->vm_flags & VM_ACCOUNT) | |
1335 | *nr_accounted += (end - start) >> PAGE_SHIFT; | |
1336 | ||
34801ba9 | 1337 | if (unlikely(is_pfn_mapping(vma))) |
2ab64037 | 1338 | untrack_pfn_vma(vma, 0, 0); |
1339 | ||
1da177e4 | 1340 | while (start != end) { |
51c6f666 | 1341 | if (unlikely(is_vm_hugetlb_page(vma))) { |
a137e1cc AK |
1342 | /* |
1343 | * It is undesirable to test vma->vm_file as it | |
1344 | * should be non-null for valid hugetlb area. | |
1345 | * However, vm_file will be NULL in the error | |
1346 | * cleanup path of do_mmap_pgoff. When | |
1347 | * hugetlbfs ->mmap method fails, | |
1348 | * do_mmap_pgoff() nullifies vma->vm_file | |
1349 | * before calling this function to clean up. | |
1350 | * Since no pte has actually been setup, it is | |
1351 | * safe to do nothing in this case. | |
1352 | */ | |
97a89413 | 1353 | if (vma->vm_file) |
a137e1cc | 1354 | unmap_hugepage_range(vma, start, end, NULL); |
a137e1cc | 1355 | |
51c6f666 RH |
1356 | start = end; |
1357 | } else | |
97a89413 | 1358 | start = unmap_page_range(tlb, vma, start, end, details); |
1da177e4 LT |
1359 | } |
1360 | } | |
97a89413 | 1361 | |
cddb8a5c | 1362 | mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); |
ee39b37b | 1363 | return start; /* which is now the end (or restart) address */ |
1da177e4 LT |
1364 | } |
1365 | ||
1366 | /** | |
1367 | * zap_page_range - remove user pages in a given range | |
1368 | * @vma: vm_area_struct holding the applicable pages | |
1369 | * @address: starting address of pages to zap | |
1370 | * @size: number of bytes to zap | |
1371 | * @details: details of nonlinear truncation or shared cache invalidation | |
1372 | */ | |
ee39b37b | 1373 | unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
1374 | unsigned long size, struct zap_details *details) |
1375 | { | |
1376 | struct mm_struct *mm = vma->vm_mm; | |
d16dfc55 | 1377 | struct mmu_gather tlb; |
1da177e4 LT |
1378 | unsigned long end = address + size; |
1379 | unsigned long nr_accounted = 0; | |
1380 | ||
1da177e4 | 1381 | lru_add_drain(); |
d16dfc55 | 1382 | tlb_gather_mmu(&tlb, mm, 0); |
365e9c87 | 1383 | update_hiwater_rss(mm); |
508034a3 | 1384 | end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); |
d16dfc55 | 1385 | tlb_finish_mmu(&tlb, address, end); |
ee39b37b | 1386 | return end; |
1da177e4 LT |
1387 | } |
1388 | ||
c627f9cc JS |
1389 | /** |
1390 | * zap_vma_ptes - remove ptes mapping the vma | |
1391 | * @vma: vm_area_struct holding ptes to be zapped | |
1392 | * @address: starting address of pages to zap | |
1393 | * @size: number of bytes to zap | |
1394 | * | |
1395 | * This function only unmaps ptes assigned to VM_PFNMAP vmas. | |
1396 | * | |
1397 | * The entire address range must be fully contained within the vma. | |
1398 | * | |
1399 | * Returns 0 if successful. | |
1400 | */ | |
1401 | int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, | |
1402 | unsigned long size) | |
1403 | { | |
1404 | if (address < vma->vm_start || address + size > vma->vm_end || | |
1405 | !(vma->vm_flags & VM_PFNMAP)) | |
1406 | return -1; | |
1407 | zap_page_range(vma, address, size, NULL); | |
1408 | return 0; | |
1409 | } | |
1410 | EXPORT_SYMBOL_GPL(zap_vma_ptes); | |
1411 | ||
142762bd JW |
1412 | /** |
1413 | * follow_page - look up a page descriptor from a user-virtual address | |
1414 | * @vma: vm_area_struct mapping @address | |
1415 | * @address: virtual address to look up | |
1416 | * @flags: flags modifying lookup behaviour | |
1417 | * | |
1418 | * @flags can have FOLL_ flags set, defined in <linux/mm.h> | |
1419 | * | |
1420 | * Returns the mapped (struct page *), %NULL if no mapping exists, or | |
1421 | * an error pointer if there is a mapping to something not represented | |
1422 | * by a page descriptor (see also vm_normal_page()). | |
1da177e4 | 1423 | */ |
6aab341e | 1424 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1425 | unsigned int flags) |
1da177e4 LT |
1426 | { |
1427 | pgd_t *pgd; | |
1428 | pud_t *pud; | |
1429 | pmd_t *pmd; | |
1430 | pte_t *ptep, pte; | |
deceb6cd | 1431 | spinlock_t *ptl; |
1da177e4 | 1432 | struct page *page; |
6aab341e | 1433 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1434 | |
deceb6cd HD |
1435 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
1436 | if (!IS_ERR(page)) { | |
1437 | BUG_ON(flags & FOLL_GET); | |
1438 | goto out; | |
1439 | } | |
1da177e4 | 1440 | |
deceb6cd | 1441 | page = NULL; |
1da177e4 LT |
1442 | pgd = pgd_offset(mm, address); |
1443 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
deceb6cd | 1444 | goto no_page_table; |
1da177e4 LT |
1445 | |
1446 | pud = pud_offset(pgd, address); | |
ceb86879 | 1447 | if (pud_none(*pud)) |
deceb6cd | 1448 | goto no_page_table; |
8a07651e | 1449 | if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) { |
ceb86879 AK |
1450 | BUG_ON(flags & FOLL_GET); |
1451 | page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE); | |
1452 | goto out; | |
1453 | } | |
1454 | if (unlikely(pud_bad(*pud))) | |
1455 | goto no_page_table; | |
1456 | ||
1da177e4 | 1457 | pmd = pmd_offset(pud, address); |
aeed5fce | 1458 | if (pmd_none(*pmd)) |
deceb6cd | 1459 | goto no_page_table; |
71e3aac0 | 1460 | if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) { |
deceb6cd HD |
1461 | BUG_ON(flags & FOLL_GET); |
1462 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); | |
1da177e4 | 1463 | goto out; |
deceb6cd | 1464 | } |
71e3aac0 | 1465 | if (pmd_trans_huge(*pmd)) { |
500d65d4 AA |
1466 | if (flags & FOLL_SPLIT) { |
1467 | split_huge_page_pmd(mm, pmd); | |
1468 | goto split_fallthrough; | |
1469 | } | |
71e3aac0 AA |
1470 | spin_lock(&mm->page_table_lock); |
1471 | if (likely(pmd_trans_huge(*pmd))) { | |
1472 | if (unlikely(pmd_trans_splitting(*pmd))) { | |
1473 | spin_unlock(&mm->page_table_lock); | |
1474 | wait_split_huge_page(vma->anon_vma, pmd); | |
1475 | } else { | |
1476 | page = follow_trans_huge_pmd(mm, address, | |
1477 | pmd, flags); | |
1478 | spin_unlock(&mm->page_table_lock); | |
1479 | goto out; | |
1480 | } | |
1481 | } else | |
1482 | spin_unlock(&mm->page_table_lock); | |
1483 | /* fall through */ | |
1484 | } | |
500d65d4 | 1485 | split_fallthrough: |
aeed5fce HD |
1486 | if (unlikely(pmd_bad(*pmd))) |
1487 | goto no_page_table; | |
1488 | ||
deceb6cd | 1489 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
1490 | |
1491 | pte = *ptep; | |
deceb6cd | 1492 | if (!pte_present(pte)) |
89f5b7da | 1493 | goto no_page; |
deceb6cd HD |
1494 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
1495 | goto unlock; | |
a13ea5b7 | 1496 | |
6aab341e | 1497 | page = vm_normal_page(vma, address, pte); |
a13ea5b7 HD |
1498 | if (unlikely(!page)) { |
1499 | if ((flags & FOLL_DUMP) || | |
62eede62 | 1500 | !is_zero_pfn(pte_pfn(pte))) |
a13ea5b7 HD |
1501 | goto bad_page; |
1502 | page = pte_page(pte); | |
1503 | } | |
1da177e4 | 1504 | |
deceb6cd HD |
1505 | if (flags & FOLL_GET) |
1506 | get_page(page); | |
1507 | if (flags & FOLL_TOUCH) { | |
1508 | if ((flags & FOLL_WRITE) && | |
1509 | !pte_dirty(pte) && !PageDirty(page)) | |
1510 | set_page_dirty(page); | |
bd775c42 KM |
1511 | /* |
1512 | * pte_mkyoung() would be more correct here, but atomic care | |
1513 | * is needed to avoid losing the dirty bit: it is easier to use | |
1514 | * mark_page_accessed(). | |
1515 | */ | |
deceb6cd HD |
1516 | mark_page_accessed(page); |
1517 | } | |
a1fde08c | 1518 | if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) { |
110d74a9 ML |
1519 | /* |
1520 | * The preliminary mapping check is mainly to avoid the | |
1521 | * pointless overhead of lock_page on the ZERO_PAGE | |
1522 | * which might bounce very badly if there is contention. | |
1523 | * | |
1524 | * If the page is already locked, we don't need to | |
1525 | * handle it now - vmscan will handle it later if and | |
1526 | * when it attempts to reclaim the page. | |
1527 | */ | |
1528 | if (page->mapping && trylock_page(page)) { | |
1529 | lru_add_drain(); /* push cached pages to LRU */ | |
1530 | /* | |
1531 | * Because we lock page here and migration is | |
1532 | * blocked by the pte's page reference, we need | |
1533 | * only check for file-cache page truncation. | |
1534 | */ | |
1535 | if (page->mapping) | |
1536 | mlock_vma_page(page); | |
1537 | unlock_page(page); | |
1538 | } | |
1539 | } | |
deceb6cd HD |
1540 | unlock: |
1541 | pte_unmap_unlock(ptep, ptl); | |
1da177e4 | 1542 | out: |
deceb6cd | 1543 | return page; |
1da177e4 | 1544 | |
89f5b7da LT |
1545 | bad_page: |
1546 | pte_unmap_unlock(ptep, ptl); | |
1547 | return ERR_PTR(-EFAULT); | |
1548 | ||
1549 | no_page: | |
1550 | pte_unmap_unlock(ptep, ptl); | |
1551 | if (!pte_none(pte)) | |
1552 | return page; | |
8e4b9a60 | 1553 | |
deceb6cd HD |
1554 | no_page_table: |
1555 | /* | |
1556 | * When core dumping an enormous anonymous area that nobody | |
8e4b9a60 HD |
1557 | * has touched so far, we don't want to allocate unnecessary pages or |
1558 | * page tables. Return error instead of NULL to skip handle_mm_fault, | |
1559 | * then get_dump_page() will return NULL to leave a hole in the dump. | |
1560 | * But we can only make this optimization where a hole would surely | |
1561 | * be zero-filled if handle_mm_fault() actually did handle it. | |
deceb6cd | 1562 | */ |
8e4b9a60 HD |
1563 | if ((flags & FOLL_DUMP) && |
1564 | (!vma->vm_ops || !vma->vm_ops->fault)) | |
1565 | return ERR_PTR(-EFAULT); | |
deceb6cd | 1566 | return page; |
1da177e4 LT |
1567 | } |
1568 | ||
95042f9e LT |
1569 | static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr) |
1570 | { | |
a09a79f6 MP |
1571 | return stack_guard_page_start(vma, addr) || |
1572 | stack_guard_page_end(vma, addr+PAGE_SIZE); | |
95042f9e LT |
1573 | } |
1574 | ||
0014bd99 HY |
1575 | /** |
1576 | * __get_user_pages() - pin user pages in memory | |
1577 | * @tsk: task_struct of target task | |
1578 | * @mm: mm_struct of target mm | |
1579 | * @start: starting user address | |
1580 | * @nr_pages: number of pages from start to pin | |
1581 | * @gup_flags: flags modifying pin behaviour | |
1582 | * @pages: array that receives pointers to the pages pinned. | |
1583 | * Should be at least nr_pages long. Or NULL, if caller | |
1584 | * only intends to ensure the pages are faulted in. | |
1585 | * @vmas: array of pointers to vmas corresponding to each page. | |
1586 | * Or NULL if the caller does not require them. | |
1587 | * @nonblocking: whether waiting for disk IO or mmap_sem contention | |
1588 | * | |
1589 | * Returns number of pages pinned. This may be fewer than the number | |
1590 | * requested. If nr_pages is 0 or negative, returns 0. If no pages | |
1591 | * were pinned, returns -errno. Each page returned must be released | |
1592 | * with a put_page() call when it is finished with. vmas will only | |
1593 | * remain valid while mmap_sem is held. | |
1594 | * | |
1595 | * Must be called with mmap_sem held for read or write. | |
1596 | * | |
1597 | * __get_user_pages walks a process's page tables and takes a reference to | |
1598 | * each struct page that each user address corresponds to at a given | |
1599 | * instant. That is, it takes the page that would be accessed if a user | |
1600 | * thread accesses the given user virtual address at that instant. | |
1601 | * | |
1602 | * This does not guarantee that the page exists in the user mappings when | |
1603 | * __get_user_pages returns, and there may even be a completely different | |
1604 | * page there in some cases (eg. if mmapped pagecache has been invalidated | |
1605 | * and subsequently re faulted). However it does guarantee that the page | |
1606 | * won't be freed completely. And mostly callers simply care that the page | |
1607 | * contains data that was valid *at some point in time*. Typically, an IO | |
1608 | * or similar operation cannot guarantee anything stronger anyway because | |
1609 | * locks can't be held over the syscall boundary. | |
1610 | * | |
1611 | * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If | |
1612 | * the page is written to, set_page_dirty (or set_page_dirty_lock, as | |
1613 | * appropriate) must be called after the page is finished with, and | |
1614 | * before put_page is called. | |
1615 | * | |
1616 | * If @nonblocking != NULL, __get_user_pages will not wait for disk IO | |
1617 | * or mmap_sem contention, and if waiting is needed to pin all pages, | |
1618 | * *@nonblocking will be set to 0. | |
1619 | * | |
1620 | * In most cases, get_user_pages or get_user_pages_fast should be used | |
1621 | * instead of __get_user_pages. __get_user_pages should be used only if | |
1622 | * you need some special @gup_flags. | |
1623 | */ | |
b291f000 | 1624 | int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
58fa879e | 1625 | unsigned long start, int nr_pages, unsigned int gup_flags, |
53a7706d ML |
1626 | struct page **pages, struct vm_area_struct **vmas, |
1627 | int *nonblocking) | |
1da177e4 LT |
1628 | { |
1629 | int i; | |
58fa879e | 1630 | unsigned long vm_flags; |
1da177e4 | 1631 | |
9d73777e | 1632 | if (nr_pages <= 0) |
900cf086 | 1633 | return 0; |
58fa879e HD |
1634 | |
1635 | VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET)); | |
1636 | ||
1da177e4 LT |
1637 | /* |
1638 | * Require read or write permissions. | |
58fa879e | 1639 | * If FOLL_FORCE is set, we only require the "MAY" flags. |
1da177e4 | 1640 | */ |
58fa879e HD |
1641 | vm_flags = (gup_flags & FOLL_WRITE) ? |
1642 | (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); | |
1643 | vm_flags &= (gup_flags & FOLL_FORCE) ? | |
1644 | (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 LT |
1645 | i = 0; |
1646 | ||
1647 | do { | |
deceb6cd | 1648 | struct vm_area_struct *vma; |
1da177e4 LT |
1649 | |
1650 | vma = find_extend_vma(mm, start); | |
e7f22e20 | 1651 | if (!vma && in_gate_area(mm, start)) { |
1da177e4 | 1652 | unsigned long pg = start & PAGE_MASK; |
1da177e4 LT |
1653 | pgd_t *pgd; |
1654 | pud_t *pud; | |
1655 | pmd_t *pmd; | |
1656 | pte_t *pte; | |
b291f000 NP |
1657 | |
1658 | /* user gate pages are read-only */ | |
58fa879e | 1659 | if (gup_flags & FOLL_WRITE) |
1da177e4 LT |
1660 | return i ? : -EFAULT; |
1661 | if (pg > TASK_SIZE) | |
1662 | pgd = pgd_offset_k(pg); | |
1663 | else | |
1664 | pgd = pgd_offset_gate(mm, pg); | |
1665 | BUG_ON(pgd_none(*pgd)); | |
1666 | pud = pud_offset(pgd, pg); | |
1667 | BUG_ON(pud_none(*pud)); | |
1668 | pmd = pmd_offset(pud, pg); | |
690dbe1c HD |
1669 | if (pmd_none(*pmd)) |
1670 | return i ? : -EFAULT; | |
f66055ab | 1671 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
1da177e4 | 1672 | pte = pte_offset_map(pmd, pg); |
690dbe1c HD |
1673 | if (pte_none(*pte)) { |
1674 | pte_unmap(pte); | |
1675 | return i ? : -EFAULT; | |
1676 | } | |
95042f9e | 1677 | vma = get_gate_vma(mm); |
1da177e4 | 1678 | if (pages) { |
de51257a HD |
1679 | struct page *page; |
1680 | ||
95042f9e | 1681 | page = vm_normal_page(vma, start, *pte); |
de51257a HD |
1682 | if (!page) { |
1683 | if (!(gup_flags & FOLL_DUMP) && | |
1684 | is_zero_pfn(pte_pfn(*pte))) | |
1685 | page = pte_page(*pte); | |
1686 | else { | |
1687 | pte_unmap(pte); | |
1688 | return i ? : -EFAULT; | |
1689 | } | |
1690 | } | |
6aab341e | 1691 | pages[i] = page; |
de51257a | 1692 | get_page(page); |
1da177e4 LT |
1693 | } |
1694 | pte_unmap(pte); | |
95042f9e | 1695 | goto next_page; |
1da177e4 LT |
1696 | } |
1697 | ||
b291f000 NP |
1698 | if (!vma || |
1699 | (vma->vm_flags & (VM_IO | VM_PFNMAP)) || | |
1c3aff1c | 1700 | !(vm_flags & vma->vm_flags)) |
1da177e4 LT |
1701 | return i ? : -EFAULT; |
1702 | ||
2a15efc9 HD |
1703 | if (is_vm_hugetlb_page(vma)) { |
1704 | i = follow_hugetlb_page(mm, vma, pages, vmas, | |
58fa879e | 1705 | &start, &nr_pages, i, gup_flags); |
2a15efc9 HD |
1706 | continue; |
1707 | } | |
deceb6cd | 1708 | |
1da177e4 | 1709 | do { |
08ef4729 | 1710 | struct page *page; |
58fa879e | 1711 | unsigned int foll_flags = gup_flags; |
1da177e4 | 1712 | |
462e00cc | 1713 | /* |
4779280d | 1714 | * If we have a pending SIGKILL, don't keep faulting |
1c3aff1c | 1715 | * pages and potentially allocating memory. |
462e00cc | 1716 | */ |
1c3aff1c | 1717 | if (unlikely(fatal_signal_pending(current))) |
4779280d | 1718 | return i ? i : -ERESTARTSYS; |
462e00cc | 1719 | |
deceb6cd | 1720 | cond_resched(); |
6aab341e | 1721 | while (!(page = follow_page(vma, start, foll_flags))) { |
deceb6cd | 1722 | int ret; |
53a7706d ML |
1723 | unsigned int fault_flags = 0; |
1724 | ||
a09a79f6 MP |
1725 | /* For mlock, just skip the stack guard page. */ |
1726 | if (foll_flags & FOLL_MLOCK) { | |
1727 | if (stack_guard_page(vma, start)) | |
1728 | goto next_page; | |
1729 | } | |
53a7706d ML |
1730 | if (foll_flags & FOLL_WRITE) |
1731 | fault_flags |= FAULT_FLAG_WRITE; | |
1732 | if (nonblocking) | |
1733 | fault_flags |= FAULT_FLAG_ALLOW_RETRY; | |
318b275f GN |
1734 | if (foll_flags & FOLL_NOWAIT) |
1735 | fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT); | |
d06063cc | 1736 | |
d26ed650 | 1737 | ret = handle_mm_fault(mm, vma, start, |
53a7706d | 1738 | fault_flags); |
d26ed650 | 1739 | |
83c54070 NP |
1740 | if (ret & VM_FAULT_ERROR) { |
1741 | if (ret & VM_FAULT_OOM) | |
1742 | return i ? i : -ENOMEM; | |
69ebb83e HY |
1743 | if (ret & (VM_FAULT_HWPOISON | |
1744 | VM_FAULT_HWPOISON_LARGE)) { | |
1745 | if (i) | |
1746 | return i; | |
1747 | else if (gup_flags & FOLL_HWPOISON) | |
1748 | return -EHWPOISON; | |
1749 | else | |
1750 | return -EFAULT; | |
1751 | } | |
1752 | if (ret & VM_FAULT_SIGBUS) | |
83c54070 NP |
1753 | return i ? i : -EFAULT; |
1754 | BUG(); | |
1755 | } | |
e7f22e20 SW |
1756 | |
1757 | if (tsk) { | |
1758 | if (ret & VM_FAULT_MAJOR) | |
1759 | tsk->maj_flt++; | |
1760 | else | |
1761 | tsk->min_flt++; | |
1762 | } | |
83c54070 | 1763 | |
53a7706d | 1764 | if (ret & VM_FAULT_RETRY) { |
318b275f GN |
1765 | if (nonblocking) |
1766 | *nonblocking = 0; | |
53a7706d ML |
1767 | return i; |
1768 | } | |
1769 | ||
a68d2ebc | 1770 | /* |
83c54070 NP |
1771 | * The VM_FAULT_WRITE bit tells us that |
1772 | * do_wp_page has broken COW when necessary, | |
1773 | * even if maybe_mkwrite decided not to set | |
1774 | * pte_write. We can thus safely do subsequent | |
878b63ac HD |
1775 | * page lookups as if they were reads. But only |
1776 | * do so when looping for pte_write is futile: | |
1777 | * in some cases userspace may also be wanting | |
1778 | * to write to the gotten user page, which a | |
1779 | * read fault here might prevent (a readonly | |
1780 | * page might get reCOWed by userspace write). | |
a68d2ebc | 1781 | */ |
878b63ac HD |
1782 | if ((ret & VM_FAULT_WRITE) && |
1783 | !(vma->vm_flags & VM_WRITE)) | |
deceb6cd | 1784 | foll_flags &= ~FOLL_WRITE; |
83c54070 | 1785 | |
7f7bbbe5 | 1786 | cond_resched(); |
1da177e4 | 1787 | } |
89f5b7da LT |
1788 | if (IS_ERR(page)) |
1789 | return i ? i : PTR_ERR(page); | |
1da177e4 | 1790 | if (pages) { |
08ef4729 | 1791 | pages[i] = page; |
03beb076 | 1792 | |
a6f36be3 | 1793 | flush_anon_page(vma, page, start); |
08ef4729 | 1794 | flush_dcache_page(page); |
1da177e4 | 1795 | } |
95042f9e | 1796 | next_page: |
1da177e4 LT |
1797 | if (vmas) |
1798 | vmas[i] = vma; | |
1799 | i++; | |
1800 | start += PAGE_SIZE; | |
9d73777e PZ |
1801 | nr_pages--; |
1802 | } while (nr_pages && start < vma->vm_end); | |
1803 | } while (nr_pages); | |
1da177e4 LT |
1804 | return i; |
1805 | } | |
0014bd99 | 1806 | EXPORT_SYMBOL(__get_user_pages); |
b291f000 | 1807 | |
2efaca92 BH |
1808 | /* |
1809 | * fixup_user_fault() - manually resolve a user page fault | |
1810 | * @tsk: the task_struct to use for page fault accounting, or | |
1811 | * NULL if faults are not to be recorded. | |
1812 | * @mm: mm_struct of target mm | |
1813 | * @address: user address | |
1814 | * @fault_flags:flags to pass down to handle_mm_fault() | |
1815 | * | |
1816 | * This is meant to be called in the specific scenario where for locking reasons | |
1817 | * we try to access user memory in atomic context (within a pagefault_disable() | |
1818 | * section), this returns -EFAULT, and we want to resolve the user fault before | |
1819 | * trying again. | |
1820 | * | |
1821 | * Typically this is meant to be used by the futex code. | |
1822 | * | |
1823 | * The main difference with get_user_pages() is that this function will | |
1824 | * unconditionally call handle_mm_fault() which will in turn perform all the | |
1825 | * necessary SW fixup of the dirty and young bits in the PTE, while | |
1826 | * handle_mm_fault() only guarantees to update these in the struct page. | |
1827 | * | |
1828 | * This is important for some architectures where those bits also gate the | |
1829 | * access permission to the page because they are maintained in software. On | |
1830 | * such architectures, gup() will not be enough to make a subsequent access | |
1831 | * succeed. | |
1832 | * | |
1833 | * This should be called with the mm_sem held for read. | |
1834 | */ | |
1835 | int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm, | |
1836 | unsigned long address, unsigned int fault_flags) | |
1837 | { | |
1838 | struct vm_area_struct *vma; | |
1839 | int ret; | |
1840 | ||
1841 | vma = find_extend_vma(mm, address); | |
1842 | if (!vma || address < vma->vm_start) | |
1843 | return -EFAULT; | |
1844 | ||
1845 | ret = handle_mm_fault(mm, vma, address, fault_flags); | |
1846 | if (ret & VM_FAULT_ERROR) { | |
1847 | if (ret & VM_FAULT_OOM) | |
1848 | return -ENOMEM; | |
1849 | if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE)) | |
1850 | return -EHWPOISON; | |
1851 | if (ret & VM_FAULT_SIGBUS) | |
1852 | return -EFAULT; | |
1853 | BUG(); | |
1854 | } | |
1855 | if (tsk) { | |
1856 | if (ret & VM_FAULT_MAJOR) | |
1857 | tsk->maj_flt++; | |
1858 | else | |
1859 | tsk->min_flt++; | |
1860 | } | |
1861 | return 0; | |
1862 | } | |
1863 | ||
1864 | /* | |
d2bf6be8 | 1865 | * get_user_pages() - pin user pages in memory |
e7f22e20 SW |
1866 | * @tsk: the task_struct to use for page fault accounting, or |
1867 | * NULL if faults are not to be recorded. | |
d2bf6be8 NP |
1868 | * @mm: mm_struct of target mm |
1869 | * @start: starting user address | |
9d73777e | 1870 | * @nr_pages: number of pages from start to pin |
d2bf6be8 NP |
1871 | * @write: whether pages will be written to by the caller |
1872 | * @force: whether to force write access even if user mapping is | |
1873 | * readonly. This will result in the page being COWed even | |
1874 | * in MAP_SHARED mappings. You do not want this. | |
1875 | * @pages: array that receives pointers to the pages pinned. | |
1876 | * Should be at least nr_pages long. Or NULL, if caller | |
1877 | * only intends to ensure the pages are faulted in. | |
1878 | * @vmas: array of pointers to vmas corresponding to each page. | |
1879 | * Or NULL if the caller does not require them. | |
1880 | * | |
1881 | * Returns number of pages pinned. This may be fewer than the number | |
9d73777e | 1882 | * requested. If nr_pages is 0 or negative, returns 0. If no pages |
d2bf6be8 NP |
1883 | * were pinned, returns -errno. Each page returned must be released |
1884 | * with a put_page() call when it is finished with. vmas will only | |
1885 | * remain valid while mmap_sem is held. | |
1886 | * | |
1887 | * Must be called with mmap_sem held for read or write. | |
1888 | * | |
1889 | * get_user_pages walks a process's page tables and takes a reference to | |
1890 | * each struct page that each user address corresponds to at a given | |
1891 | * instant. That is, it takes the page that would be accessed if a user | |
1892 | * thread accesses the given user virtual address at that instant. | |
1893 | * | |
1894 | * This does not guarantee that the page exists in the user mappings when | |
1895 | * get_user_pages returns, and there may even be a completely different | |
1896 | * page there in some cases (eg. if mmapped pagecache has been invalidated | |
1897 | * and subsequently re faulted). However it does guarantee that the page | |
1898 | * won't be freed completely. And mostly callers simply care that the page | |
1899 | * contains data that was valid *at some point in time*. Typically, an IO | |
1900 | * or similar operation cannot guarantee anything stronger anyway because | |
1901 | * locks can't be held over the syscall boundary. | |
1902 | * | |
1903 | * If write=0, the page must not be written to. If the page is written to, | |
1904 | * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called | |
1905 | * after the page is finished with, and before put_page is called. | |
1906 | * | |
1907 | * get_user_pages is typically used for fewer-copy IO operations, to get a | |
1908 | * handle on the memory by some means other than accesses via the user virtual | |
1909 | * addresses. The pages may be submitted for DMA to devices or accessed via | |
1910 | * their kernel linear mapping (via the kmap APIs). Care should be taken to | |
1911 | * use the correct cache flushing APIs. | |
1912 | * | |
1913 | * See also get_user_pages_fast, for performance critical applications. | |
1914 | */ | |
b291f000 | 1915 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
9d73777e | 1916 | unsigned long start, int nr_pages, int write, int force, |
b291f000 NP |
1917 | struct page **pages, struct vm_area_struct **vmas) |
1918 | { | |
58fa879e | 1919 | int flags = FOLL_TOUCH; |
b291f000 | 1920 | |
58fa879e HD |
1921 | if (pages) |
1922 | flags |= FOLL_GET; | |
b291f000 | 1923 | if (write) |
58fa879e | 1924 | flags |= FOLL_WRITE; |
b291f000 | 1925 | if (force) |
58fa879e | 1926 | flags |= FOLL_FORCE; |
b291f000 | 1927 | |
53a7706d ML |
1928 | return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas, |
1929 | NULL); | |
b291f000 | 1930 | } |
1da177e4 LT |
1931 | EXPORT_SYMBOL(get_user_pages); |
1932 | ||
f3e8fccd HD |
1933 | /** |
1934 | * get_dump_page() - pin user page in memory while writing it to core dump | |
1935 | * @addr: user address | |
1936 | * | |
1937 | * Returns struct page pointer of user page pinned for dump, | |
1938 | * to be freed afterwards by page_cache_release() or put_page(). | |
1939 | * | |
1940 | * Returns NULL on any kind of failure - a hole must then be inserted into | |
1941 | * the corefile, to preserve alignment with its headers; and also returns | |
1942 | * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found - | |
1943 | * allowing a hole to be left in the corefile to save diskspace. | |
1944 | * | |
1945 | * Called without mmap_sem, but after all other threads have been killed. | |
1946 | */ | |
1947 | #ifdef CONFIG_ELF_CORE | |
1948 | struct page *get_dump_page(unsigned long addr) | |
1949 | { | |
1950 | struct vm_area_struct *vma; | |
1951 | struct page *page; | |
1952 | ||
1953 | if (__get_user_pages(current, current->mm, addr, 1, | |
53a7706d ML |
1954 | FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma, |
1955 | NULL) < 1) | |
f3e8fccd | 1956 | return NULL; |
f3e8fccd HD |
1957 | flush_cache_page(vma, addr, page_to_pfn(page)); |
1958 | return page; | |
1959 | } | |
1960 | #endif /* CONFIG_ELF_CORE */ | |
1961 | ||
25ca1d6c | 1962 | pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, |
920c7a5d | 1963 | spinlock_t **ptl) |
c9cfcddf LT |
1964 | { |
1965 | pgd_t * pgd = pgd_offset(mm, addr); | |
1966 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
1967 | if (pud) { | |
49c91fb0 | 1968 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
f66055ab AA |
1969 | if (pmd) { |
1970 | VM_BUG_ON(pmd_trans_huge(*pmd)); | |
c9cfcddf | 1971 | return pte_alloc_map_lock(mm, pmd, addr, ptl); |
f66055ab | 1972 | } |
c9cfcddf LT |
1973 | } |
1974 | return NULL; | |
1975 | } | |
1976 | ||
238f58d8 LT |
1977 | /* |
1978 | * This is the old fallback for page remapping. | |
1979 | * | |
1980 | * For historical reasons, it only allows reserved pages. Only | |
1981 | * old drivers should use this, and they needed to mark their | |
1982 | * pages reserved for the old functions anyway. | |
1983 | */ | |
423bad60 NP |
1984 | static int insert_page(struct vm_area_struct *vma, unsigned long addr, |
1985 | struct page *page, pgprot_t prot) | |
238f58d8 | 1986 | { |
423bad60 | 1987 | struct mm_struct *mm = vma->vm_mm; |
238f58d8 | 1988 | int retval; |
c9cfcddf | 1989 | pte_t *pte; |
8a9f3ccd BS |
1990 | spinlock_t *ptl; |
1991 | ||
238f58d8 | 1992 | retval = -EINVAL; |
a145dd41 | 1993 | if (PageAnon(page)) |
5b4e655e | 1994 | goto out; |
238f58d8 LT |
1995 | retval = -ENOMEM; |
1996 | flush_dcache_page(page); | |
c9cfcddf | 1997 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 | 1998 | if (!pte) |
5b4e655e | 1999 | goto out; |
238f58d8 LT |
2000 | retval = -EBUSY; |
2001 | if (!pte_none(*pte)) | |
2002 | goto out_unlock; | |
2003 | ||
2004 | /* Ok, finally just insert the thing.. */ | |
2005 | get_page(page); | |
34e55232 | 2006 | inc_mm_counter_fast(mm, MM_FILEPAGES); |
238f58d8 LT |
2007 | page_add_file_rmap(page); |
2008 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); | |
2009 | ||
2010 | retval = 0; | |
8a9f3ccd BS |
2011 | pte_unmap_unlock(pte, ptl); |
2012 | return retval; | |
238f58d8 LT |
2013 | out_unlock: |
2014 | pte_unmap_unlock(pte, ptl); | |
2015 | out: | |
2016 | return retval; | |
2017 | } | |
2018 | ||
bfa5bf6d REB |
2019 | /** |
2020 | * vm_insert_page - insert single page into user vma | |
2021 | * @vma: user vma to map to | |
2022 | * @addr: target user address of this page | |
2023 | * @page: source kernel page | |
2024 | * | |
a145dd41 LT |
2025 | * This allows drivers to insert individual pages they've allocated |
2026 | * into a user vma. | |
2027 | * | |
2028 | * The page has to be a nice clean _individual_ kernel allocation. | |
2029 | * If you allocate a compound page, you need to have marked it as | |
2030 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 2031 | * (see split_page()). |
a145dd41 LT |
2032 | * |
2033 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
2034 | * took an arbitrary page protection parameter. This doesn't allow | |
2035 | * that. Your vma protection will have to be set up correctly, which | |
2036 | * means that if you want a shared writable mapping, you'd better | |
2037 | * ask for a shared writable mapping! | |
2038 | * | |
2039 | * The page does not need to be reserved. | |
2040 | */ | |
423bad60 NP |
2041 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
2042 | struct page *page) | |
a145dd41 LT |
2043 | { |
2044 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
2045 | return -EFAULT; | |
2046 | if (!page_count(page)) | |
2047 | return -EINVAL; | |
4d7672b4 | 2048 | vma->vm_flags |= VM_INSERTPAGE; |
423bad60 | 2049 | return insert_page(vma, addr, page, vma->vm_page_prot); |
a145dd41 | 2050 | } |
e3c3374f | 2051 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 2052 | |
423bad60 NP |
2053 | static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, |
2054 | unsigned long pfn, pgprot_t prot) | |
2055 | { | |
2056 | struct mm_struct *mm = vma->vm_mm; | |
2057 | int retval; | |
2058 | pte_t *pte, entry; | |
2059 | spinlock_t *ptl; | |
2060 | ||
2061 | retval = -ENOMEM; | |
2062 | pte = get_locked_pte(mm, addr, &ptl); | |
2063 | if (!pte) | |
2064 | goto out; | |
2065 | retval = -EBUSY; | |
2066 | if (!pte_none(*pte)) | |
2067 | goto out_unlock; | |
2068 | ||
2069 | /* Ok, finally just insert the thing.. */ | |
2070 | entry = pte_mkspecial(pfn_pte(pfn, prot)); | |
2071 | set_pte_at(mm, addr, pte, entry); | |
4b3073e1 | 2072 | update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ |
423bad60 NP |
2073 | |
2074 | retval = 0; | |
2075 | out_unlock: | |
2076 | pte_unmap_unlock(pte, ptl); | |
2077 | out: | |
2078 | return retval; | |
2079 | } | |
2080 | ||
e0dc0d8f NP |
2081 | /** |
2082 | * vm_insert_pfn - insert single pfn into user vma | |
2083 | * @vma: user vma to map to | |
2084 | * @addr: target user address of this page | |
2085 | * @pfn: source kernel pfn | |
2086 | * | |
2087 | * Similar to vm_inert_page, this allows drivers to insert individual pages | |
2088 | * they've allocated into a user vma. Same comments apply. | |
2089 | * | |
2090 | * This function should only be called from a vm_ops->fault handler, and | |
2091 | * in that case the handler should return NULL. | |
0d71d10a NP |
2092 | * |
2093 | * vma cannot be a COW mapping. | |
2094 | * | |
2095 | * As this is called only for pages that do not currently exist, we | |
2096 | * do not need to flush old virtual caches or the TLB. | |
e0dc0d8f NP |
2097 | */ |
2098 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
423bad60 | 2099 | unsigned long pfn) |
e0dc0d8f | 2100 | { |
2ab64037 | 2101 | int ret; |
e4b866ed | 2102 | pgprot_t pgprot = vma->vm_page_prot; |
7e675137 NP |
2103 | /* |
2104 | * Technically, architectures with pte_special can avoid all these | |
2105 | * restrictions (same for remap_pfn_range). However we would like | |
2106 | * consistency in testing and feature parity among all, so we should | |
2107 | * try to keep these invariants in place for everybody. | |
2108 | */ | |
b379d790 JH |
2109 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); |
2110 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
2111 | (VM_PFNMAP|VM_MIXEDMAP)); | |
2112 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
2113 | BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); | |
e0dc0d8f | 2114 | |
423bad60 NP |
2115 | if (addr < vma->vm_start || addr >= vma->vm_end) |
2116 | return -EFAULT; | |
e4b866ed | 2117 | if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE)) |
2ab64037 | 2118 | return -EINVAL; |
2119 | ||
e4b866ed | 2120 | ret = insert_pfn(vma, addr, pfn, pgprot); |
2ab64037 | 2121 | |
2122 | if (ret) | |
2123 | untrack_pfn_vma(vma, pfn, PAGE_SIZE); | |
2124 | ||
2125 | return ret; | |
423bad60 NP |
2126 | } |
2127 | EXPORT_SYMBOL(vm_insert_pfn); | |
e0dc0d8f | 2128 | |
423bad60 NP |
2129 | int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, |
2130 | unsigned long pfn) | |
2131 | { | |
2132 | BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); | |
e0dc0d8f | 2133 | |
423bad60 NP |
2134 | if (addr < vma->vm_start || addr >= vma->vm_end) |
2135 | return -EFAULT; | |
e0dc0d8f | 2136 | |
423bad60 NP |
2137 | /* |
2138 | * If we don't have pte special, then we have to use the pfn_valid() | |
2139 | * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* | |
2140 | * refcount the page if pfn_valid is true (hence insert_page rather | |
62eede62 HD |
2141 | * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP |
2142 | * without pte special, it would there be refcounted as a normal page. | |
423bad60 NP |
2143 | */ |
2144 | if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) { | |
2145 | struct page *page; | |
2146 | ||
2147 | page = pfn_to_page(pfn); | |
2148 | return insert_page(vma, addr, page, vma->vm_page_prot); | |
2149 | } | |
2150 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
e0dc0d8f | 2151 | } |
423bad60 | 2152 | EXPORT_SYMBOL(vm_insert_mixed); |
e0dc0d8f | 2153 | |
1da177e4 LT |
2154 | /* |
2155 | * maps a range of physical memory into the requested pages. the old | |
2156 | * mappings are removed. any references to nonexistent pages results | |
2157 | * in null mappings (currently treated as "copy-on-access") | |
2158 | */ | |
2159 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
2160 | unsigned long addr, unsigned long end, | |
2161 | unsigned long pfn, pgprot_t prot) | |
2162 | { | |
2163 | pte_t *pte; | |
c74df32c | 2164 | spinlock_t *ptl; |
1da177e4 | 2165 | |
c74df32c | 2166 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
2167 | if (!pte) |
2168 | return -ENOMEM; | |
6606c3e0 | 2169 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
2170 | do { |
2171 | BUG_ON(!pte_none(*pte)); | |
7e675137 | 2172 | set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); |
1da177e4 LT |
2173 | pfn++; |
2174 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 2175 | arch_leave_lazy_mmu_mode(); |
c74df32c | 2176 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
2177 | return 0; |
2178 | } | |
2179 | ||
2180 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
2181 | unsigned long addr, unsigned long end, | |
2182 | unsigned long pfn, pgprot_t prot) | |
2183 | { | |
2184 | pmd_t *pmd; | |
2185 | unsigned long next; | |
2186 | ||
2187 | pfn -= addr >> PAGE_SHIFT; | |
2188 | pmd = pmd_alloc(mm, pud, addr); | |
2189 | if (!pmd) | |
2190 | return -ENOMEM; | |
f66055ab | 2191 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
1da177e4 LT |
2192 | do { |
2193 | next = pmd_addr_end(addr, end); | |
2194 | if (remap_pte_range(mm, pmd, addr, next, | |
2195 | pfn + (addr >> PAGE_SHIFT), prot)) | |
2196 | return -ENOMEM; | |
2197 | } while (pmd++, addr = next, addr != end); | |
2198 | return 0; | |
2199 | } | |
2200 | ||
2201 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
2202 | unsigned long addr, unsigned long end, | |
2203 | unsigned long pfn, pgprot_t prot) | |
2204 | { | |
2205 | pud_t *pud; | |
2206 | unsigned long next; | |
2207 | ||
2208 | pfn -= addr >> PAGE_SHIFT; | |
2209 | pud = pud_alloc(mm, pgd, addr); | |
2210 | if (!pud) | |
2211 | return -ENOMEM; | |
2212 | do { | |
2213 | next = pud_addr_end(addr, end); | |
2214 | if (remap_pmd_range(mm, pud, addr, next, | |
2215 | pfn + (addr >> PAGE_SHIFT), prot)) | |
2216 | return -ENOMEM; | |
2217 | } while (pud++, addr = next, addr != end); | |
2218 | return 0; | |
2219 | } | |
2220 | ||
bfa5bf6d REB |
2221 | /** |
2222 | * remap_pfn_range - remap kernel memory to userspace | |
2223 | * @vma: user vma to map to | |
2224 | * @addr: target user address to start at | |
2225 | * @pfn: physical address of kernel memory | |
2226 | * @size: size of map area | |
2227 | * @prot: page protection flags for this mapping | |
2228 | * | |
2229 | * Note: this is only safe if the mm semaphore is held when called. | |
2230 | */ | |
1da177e4 LT |
2231 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
2232 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
2233 | { | |
2234 | pgd_t *pgd; | |
2235 | unsigned long next; | |
2d15cab8 | 2236 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 LT |
2237 | struct mm_struct *mm = vma->vm_mm; |
2238 | int err; | |
2239 | ||
2240 | /* | |
2241 | * Physically remapped pages are special. Tell the | |
2242 | * rest of the world about it: | |
2243 | * VM_IO tells people not to look at these pages | |
2244 | * (accesses can have side effects). | |
0b14c179 HD |
2245 | * VM_RESERVED is specified all over the place, because |
2246 | * in 2.4 it kept swapout's vma scan off this vma; but | |
2247 | * in 2.6 the LRU scan won't even find its pages, so this | |
2248 | * flag means no more than count its pages in reserved_vm, | |
2249 | * and omit it from core dump, even when VM_IO turned off. | |
6aab341e LT |
2250 | * VM_PFNMAP tells the core MM that the base pages are just |
2251 | * raw PFN mappings, and do not have a "struct page" associated | |
2252 | * with them. | |
fb155c16 LT |
2253 | * |
2254 | * There's a horrible special case to handle copy-on-write | |
2255 | * behaviour that some programs depend on. We mark the "original" | |
2256 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
1da177e4 | 2257 | */ |
4bb9c5c0 | 2258 | if (addr == vma->vm_start && end == vma->vm_end) { |
fb155c16 | 2259 | vma->vm_pgoff = pfn; |
895791da | 2260 | vma->vm_flags |= VM_PFN_AT_MMAP; |
4bb9c5c0 | 2261 | } else if (is_cow_mapping(vma->vm_flags)) |
3c8bb73a | 2262 | return -EINVAL; |
fb155c16 | 2263 | |
6aab341e | 2264 | vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; |
1da177e4 | 2265 | |
e4b866ed | 2266 | err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size)); |
a3670613 | 2267 | if (err) { |
2268 | /* | |
2269 | * To indicate that track_pfn related cleanup is not | |
2270 | * needed from higher level routine calling unmap_vmas | |
2271 | */ | |
2272 | vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP); | |
895791da | 2273 | vma->vm_flags &= ~VM_PFN_AT_MMAP; |
2ab64037 | 2274 | return -EINVAL; |
a3670613 | 2275 | } |
2ab64037 | 2276 | |
1da177e4 LT |
2277 | BUG_ON(addr >= end); |
2278 | pfn -= addr >> PAGE_SHIFT; | |
2279 | pgd = pgd_offset(mm, addr); | |
2280 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
2281 | do { |
2282 | next = pgd_addr_end(addr, end); | |
2283 | err = remap_pud_range(mm, pgd, addr, next, | |
2284 | pfn + (addr >> PAGE_SHIFT), prot); | |
2285 | if (err) | |
2286 | break; | |
2287 | } while (pgd++, addr = next, addr != end); | |
2ab64037 | 2288 | |
2289 | if (err) | |
2290 | untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size)); | |
2291 | ||
1da177e4 LT |
2292 | return err; |
2293 | } | |
2294 | EXPORT_SYMBOL(remap_pfn_range); | |
2295 | ||
aee16b3c JF |
2296 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
2297 | unsigned long addr, unsigned long end, | |
2298 | pte_fn_t fn, void *data) | |
2299 | { | |
2300 | pte_t *pte; | |
2301 | int err; | |
2f569afd | 2302 | pgtable_t token; |
94909914 | 2303 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
2304 | |
2305 | pte = (mm == &init_mm) ? | |
2306 | pte_alloc_kernel(pmd, addr) : | |
2307 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
2308 | if (!pte) | |
2309 | return -ENOMEM; | |
2310 | ||
2311 | BUG_ON(pmd_huge(*pmd)); | |
2312 | ||
38e0edb1 JF |
2313 | arch_enter_lazy_mmu_mode(); |
2314 | ||
2f569afd | 2315 | token = pmd_pgtable(*pmd); |
aee16b3c JF |
2316 | |
2317 | do { | |
c36987e2 | 2318 | err = fn(pte++, token, addr, data); |
aee16b3c JF |
2319 | if (err) |
2320 | break; | |
c36987e2 | 2321 | } while (addr += PAGE_SIZE, addr != end); |
aee16b3c | 2322 | |
38e0edb1 JF |
2323 | arch_leave_lazy_mmu_mode(); |
2324 | ||
aee16b3c JF |
2325 | if (mm != &init_mm) |
2326 | pte_unmap_unlock(pte-1, ptl); | |
2327 | return err; | |
2328 | } | |
2329 | ||
2330 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
2331 | unsigned long addr, unsigned long end, | |
2332 | pte_fn_t fn, void *data) | |
2333 | { | |
2334 | pmd_t *pmd; | |
2335 | unsigned long next; | |
2336 | int err; | |
2337 | ||
ceb86879 AK |
2338 | BUG_ON(pud_huge(*pud)); |
2339 | ||
aee16b3c JF |
2340 | pmd = pmd_alloc(mm, pud, addr); |
2341 | if (!pmd) | |
2342 | return -ENOMEM; | |
2343 | do { | |
2344 | next = pmd_addr_end(addr, end); | |
2345 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
2346 | if (err) | |
2347 | break; | |
2348 | } while (pmd++, addr = next, addr != end); | |
2349 | return err; | |
2350 | } | |
2351 | ||
2352 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
2353 | unsigned long addr, unsigned long end, | |
2354 | pte_fn_t fn, void *data) | |
2355 | { | |
2356 | pud_t *pud; | |
2357 | unsigned long next; | |
2358 | int err; | |
2359 | ||
2360 | pud = pud_alloc(mm, pgd, addr); | |
2361 | if (!pud) | |
2362 | return -ENOMEM; | |
2363 | do { | |
2364 | next = pud_addr_end(addr, end); | |
2365 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
2366 | if (err) | |
2367 | break; | |
2368 | } while (pud++, addr = next, addr != end); | |
2369 | return err; | |
2370 | } | |
2371 | ||
2372 | /* | |
2373 | * Scan a region of virtual memory, filling in page tables as necessary | |
2374 | * and calling a provided function on each leaf page table. | |
2375 | */ | |
2376 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
2377 | unsigned long size, pte_fn_t fn, void *data) | |
2378 | { | |
2379 | pgd_t *pgd; | |
2380 | unsigned long next; | |
57250a5b | 2381 | unsigned long end = addr + size; |
aee16b3c JF |
2382 | int err; |
2383 | ||
2384 | BUG_ON(addr >= end); | |
2385 | pgd = pgd_offset(mm, addr); | |
2386 | do { | |
2387 | next = pgd_addr_end(addr, end); | |
2388 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
2389 | if (err) | |
2390 | break; | |
2391 | } while (pgd++, addr = next, addr != end); | |
57250a5b | 2392 | |
aee16b3c JF |
2393 | return err; |
2394 | } | |
2395 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
2396 | ||
8f4e2101 HD |
2397 | /* |
2398 | * handle_pte_fault chooses page fault handler according to an entry | |
2399 | * which was read non-atomically. Before making any commitment, on | |
2400 | * those architectures or configurations (e.g. i386 with PAE) which | |
a335b2e1 | 2401 | * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault |
8f4e2101 HD |
2402 | * must check under lock before unmapping the pte and proceeding |
2403 | * (but do_wp_page is only called after already making such a check; | |
a335b2e1 | 2404 | * and do_anonymous_page can safely check later on). |
8f4e2101 | 2405 | */ |
4c21e2f2 | 2406 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
2407 | pte_t *page_table, pte_t orig_pte) |
2408 | { | |
2409 | int same = 1; | |
2410 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
2411 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
2412 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
2413 | spin_lock(ptl); | |
8f4e2101 | 2414 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 2415 | spin_unlock(ptl); |
8f4e2101 HD |
2416 | } |
2417 | #endif | |
2418 | pte_unmap(page_table); | |
2419 | return same; | |
2420 | } | |
2421 | ||
9de455b2 | 2422 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e LT |
2423 | { |
2424 | /* | |
2425 | * If the source page was a PFN mapping, we don't have | |
2426 | * a "struct page" for it. We do a best-effort copy by | |
2427 | * just copying from the original user address. If that | |
2428 | * fails, we just zero-fill it. Live with it. | |
2429 | */ | |
2430 | if (unlikely(!src)) { | |
2431 | void *kaddr = kmap_atomic(dst, KM_USER0); | |
5d2a2dbb LT |
2432 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
2433 | ||
2434 | /* | |
2435 | * This really shouldn't fail, because the page is there | |
2436 | * in the page tables. But it might just be unreadable, | |
2437 | * in which case we just give up and fill the result with | |
2438 | * zeroes. | |
2439 | */ | |
2440 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
3ecb01df | 2441 | clear_page(kaddr); |
6aab341e | 2442 | kunmap_atomic(kaddr, KM_USER0); |
c4ec7b0d | 2443 | flush_dcache_page(dst); |
0ed361de NP |
2444 | } else |
2445 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
2446 | } |
2447 | ||
1da177e4 LT |
2448 | /* |
2449 | * This routine handles present pages, when users try to write | |
2450 | * to a shared page. It is done by copying the page to a new address | |
2451 | * and decrementing the shared-page counter for the old page. | |
2452 | * | |
1da177e4 LT |
2453 | * Note that this routine assumes that the protection checks have been |
2454 | * done by the caller (the low-level page fault routine in most cases). | |
2455 | * Thus we can safely just mark it writable once we've done any necessary | |
2456 | * COW. | |
2457 | * | |
2458 | * We also mark the page dirty at this point even though the page will | |
2459 | * change only once the write actually happens. This avoids a few races, | |
2460 | * and potentially makes it more efficient. | |
2461 | * | |
8f4e2101 HD |
2462 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2463 | * but allow concurrent faults), with pte both mapped and locked. | |
2464 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2465 | */ |
65500d23 HD |
2466 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2467 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
8f4e2101 | 2468 | spinlock_t *ptl, pte_t orig_pte) |
e6219ec8 | 2469 | __releases(ptl) |
1da177e4 | 2470 | { |
e5bbe4df | 2471 | struct page *old_page, *new_page; |
1da177e4 | 2472 | pte_t entry; |
b009c024 | 2473 | int ret = 0; |
a200ee18 | 2474 | int page_mkwrite = 0; |
d08b3851 | 2475 | struct page *dirty_page = NULL; |
1da177e4 | 2476 | |
6aab341e | 2477 | old_page = vm_normal_page(vma, address, orig_pte); |
251b97f5 PZ |
2478 | if (!old_page) { |
2479 | /* | |
2480 | * VM_MIXEDMAP !pfn_valid() case | |
2481 | * | |
2482 | * We should not cow pages in a shared writeable mapping. | |
2483 | * Just mark the pages writable as we can't do any dirty | |
2484 | * accounting on raw pfn maps. | |
2485 | */ | |
2486 | if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
2487 | (VM_WRITE|VM_SHARED)) | |
2488 | goto reuse; | |
6aab341e | 2489 | goto gotten; |
251b97f5 | 2490 | } |
1da177e4 | 2491 | |
d08b3851 | 2492 | /* |
ee6a6457 PZ |
2493 | * Take out anonymous pages first, anonymous shared vmas are |
2494 | * not dirty accountable. | |
d08b3851 | 2495 | */ |
9a840895 | 2496 | if (PageAnon(old_page) && !PageKsm(old_page)) { |
ab967d86 HD |
2497 | if (!trylock_page(old_page)) { |
2498 | page_cache_get(old_page); | |
2499 | pte_unmap_unlock(page_table, ptl); | |
2500 | lock_page(old_page); | |
2501 | page_table = pte_offset_map_lock(mm, pmd, address, | |
2502 | &ptl); | |
2503 | if (!pte_same(*page_table, orig_pte)) { | |
2504 | unlock_page(old_page); | |
ab967d86 HD |
2505 | goto unlock; |
2506 | } | |
2507 | page_cache_release(old_page); | |
ee6a6457 | 2508 | } |
b009c024 | 2509 | if (reuse_swap_page(old_page)) { |
c44b6743 RR |
2510 | /* |
2511 | * The page is all ours. Move it to our anon_vma so | |
2512 | * the rmap code will not search our parent or siblings. | |
2513 | * Protected against the rmap code by the page lock. | |
2514 | */ | |
2515 | page_move_anon_rmap(old_page, vma, address); | |
b009c024 ML |
2516 | unlock_page(old_page); |
2517 | goto reuse; | |
2518 | } | |
ab967d86 | 2519 | unlock_page(old_page); |
ee6a6457 | 2520 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == |
d08b3851 | 2521 | (VM_WRITE|VM_SHARED))) { |
ee6a6457 PZ |
2522 | /* |
2523 | * Only catch write-faults on shared writable pages, | |
2524 | * read-only shared pages can get COWed by | |
2525 | * get_user_pages(.write=1, .force=1). | |
2526 | */ | |
9637a5ef | 2527 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
c2ec175c NP |
2528 | struct vm_fault vmf; |
2529 | int tmp; | |
2530 | ||
2531 | vmf.virtual_address = (void __user *)(address & | |
2532 | PAGE_MASK); | |
2533 | vmf.pgoff = old_page->index; | |
2534 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; | |
2535 | vmf.page = old_page; | |
2536 | ||
9637a5ef DH |
2537 | /* |
2538 | * Notify the address space that the page is about to | |
2539 | * become writable so that it can prohibit this or wait | |
2540 | * for the page to get into an appropriate state. | |
2541 | * | |
2542 | * We do this without the lock held, so that it can | |
2543 | * sleep if it needs to. | |
2544 | */ | |
2545 | page_cache_get(old_page); | |
2546 | pte_unmap_unlock(page_table, ptl); | |
2547 | ||
c2ec175c NP |
2548 | tmp = vma->vm_ops->page_mkwrite(vma, &vmf); |
2549 | if (unlikely(tmp & | |
2550 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { | |
2551 | ret = tmp; | |
9637a5ef | 2552 | goto unwritable_page; |
c2ec175c | 2553 | } |
b827e496 NP |
2554 | if (unlikely(!(tmp & VM_FAULT_LOCKED))) { |
2555 | lock_page(old_page); | |
2556 | if (!old_page->mapping) { | |
2557 | ret = 0; /* retry the fault */ | |
2558 | unlock_page(old_page); | |
2559 | goto unwritable_page; | |
2560 | } | |
2561 | } else | |
2562 | VM_BUG_ON(!PageLocked(old_page)); | |
9637a5ef | 2563 | |
9637a5ef DH |
2564 | /* |
2565 | * Since we dropped the lock we need to revalidate | |
2566 | * the PTE as someone else may have changed it. If | |
2567 | * they did, we just return, as we can count on the | |
2568 | * MMU to tell us if they didn't also make it writable. | |
2569 | */ | |
2570 | page_table = pte_offset_map_lock(mm, pmd, address, | |
2571 | &ptl); | |
b827e496 NP |
2572 | if (!pte_same(*page_table, orig_pte)) { |
2573 | unlock_page(old_page); | |
9637a5ef | 2574 | goto unlock; |
b827e496 | 2575 | } |
a200ee18 PZ |
2576 | |
2577 | page_mkwrite = 1; | |
1da177e4 | 2578 | } |
d08b3851 PZ |
2579 | dirty_page = old_page; |
2580 | get_page(dirty_page); | |
9637a5ef | 2581 | |
251b97f5 | 2582 | reuse: |
9637a5ef DH |
2583 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
2584 | entry = pte_mkyoung(orig_pte); | |
2585 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
954ffcb3 | 2586 | if (ptep_set_access_flags(vma, address, page_table, entry,1)) |
4b3073e1 | 2587 | update_mmu_cache(vma, address, page_table); |
72ddc8f7 | 2588 | pte_unmap_unlock(page_table, ptl); |
9637a5ef | 2589 | ret |= VM_FAULT_WRITE; |
72ddc8f7 ML |
2590 | |
2591 | if (!dirty_page) | |
2592 | return ret; | |
2593 | ||
2594 | /* | |
2595 | * Yes, Virginia, this is actually required to prevent a race | |
2596 | * with clear_page_dirty_for_io() from clearing the page dirty | |
2597 | * bit after it clear all dirty ptes, but before a racing | |
2598 | * do_wp_page installs a dirty pte. | |
2599 | * | |
a335b2e1 | 2600 | * __do_fault is protected similarly. |
72ddc8f7 ML |
2601 | */ |
2602 | if (!page_mkwrite) { | |
2603 | wait_on_page_locked(dirty_page); | |
2604 | set_page_dirty_balance(dirty_page, page_mkwrite); | |
2605 | } | |
2606 | put_page(dirty_page); | |
2607 | if (page_mkwrite) { | |
2608 | struct address_space *mapping = dirty_page->mapping; | |
2609 | ||
2610 | set_page_dirty(dirty_page); | |
2611 | unlock_page(dirty_page); | |
2612 | page_cache_release(dirty_page); | |
2613 | if (mapping) { | |
2614 | /* | |
2615 | * Some device drivers do not set page.mapping | |
2616 | * but still dirty their pages | |
2617 | */ | |
2618 | balance_dirty_pages_ratelimited(mapping); | |
2619 | } | |
2620 | } | |
2621 | ||
2622 | /* file_update_time outside page_lock */ | |
2623 | if (vma->vm_file) | |
2624 | file_update_time(vma->vm_file); | |
2625 | ||
2626 | return ret; | |
1da177e4 | 2627 | } |
1da177e4 LT |
2628 | |
2629 | /* | |
2630 | * Ok, we need to copy. Oh, well.. | |
2631 | */ | |
b5810039 | 2632 | page_cache_get(old_page); |
920fc356 | 2633 | gotten: |
8f4e2101 | 2634 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2635 | |
2636 | if (unlikely(anon_vma_prepare(vma))) | |
65500d23 | 2637 | goto oom; |
a13ea5b7 | 2638 | |
62eede62 | 2639 | if (is_zero_pfn(pte_pfn(orig_pte))) { |
a13ea5b7 HD |
2640 | new_page = alloc_zeroed_user_highpage_movable(vma, address); |
2641 | if (!new_page) | |
2642 | goto oom; | |
2643 | } else { | |
2644 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
2645 | if (!new_page) | |
2646 | goto oom; | |
2647 | cow_user_page(new_page, old_page, address, vma); | |
2648 | } | |
2649 | __SetPageUptodate(new_page); | |
2650 | ||
2c26fdd7 | 2651 | if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
2652 | goto oom_free_new; |
2653 | ||
1da177e4 LT |
2654 | /* |
2655 | * Re-check the pte - we dropped the lock | |
2656 | */ | |
8f4e2101 | 2657 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
65500d23 | 2658 | if (likely(pte_same(*page_table, orig_pte))) { |
920fc356 | 2659 | if (old_page) { |
920fc356 | 2660 | if (!PageAnon(old_page)) { |
34e55232 KH |
2661 | dec_mm_counter_fast(mm, MM_FILEPAGES); |
2662 | inc_mm_counter_fast(mm, MM_ANONPAGES); | |
920fc356 HD |
2663 | } |
2664 | } else | |
34e55232 | 2665 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
eca35133 | 2666 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
65500d23 HD |
2667 | entry = mk_pte(new_page, vma->vm_page_prot); |
2668 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
4ce072f1 SS |
2669 | /* |
2670 | * Clear the pte entry and flush it first, before updating the | |
2671 | * pte with the new entry. This will avoid a race condition | |
2672 | * seen in the presence of one thread doing SMC and another | |
2673 | * thread doing COW. | |
2674 | */ | |
828502d3 | 2675 | ptep_clear_flush(vma, address, page_table); |
9617d95e | 2676 | page_add_new_anon_rmap(new_page, vma, address); |
828502d3 IE |
2677 | /* |
2678 | * We call the notify macro here because, when using secondary | |
2679 | * mmu page tables (such as kvm shadow page tables), we want the | |
2680 | * new page to be mapped directly into the secondary page table. | |
2681 | */ | |
2682 | set_pte_at_notify(mm, address, page_table, entry); | |
4b3073e1 | 2683 | update_mmu_cache(vma, address, page_table); |
945754a1 NP |
2684 | if (old_page) { |
2685 | /* | |
2686 | * Only after switching the pte to the new page may | |
2687 | * we remove the mapcount here. Otherwise another | |
2688 | * process may come and find the rmap count decremented | |
2689 | * before the pte is switched to the new page, and | |
2690 | * "reuse" the old page writing into it while our pte | |
2691 | * here still points into it and can be read by other | |
2692 | * threads. | |
2693 | * | |
2694 | * The critical issue is to order this | |
2695 | * page_remove_rmap with the ptp_clear_flush above. | |
2696 | * Those stores are ordered by (if nothing else,) | |
2697 | * the barrier present in the atomic_add_negative | |
2698 | * in page_remove_rmap. | |
2699 | * | |
2700 | * Then the TLB flush in ptep_clear_flush ensures that | |
2701 | * no process can access the old page before the | |
2702 | * decremented mapcount is visible. And the old page | |
2703 | * cannot be reused until after the decremented | |
2704 | * mapcount is visible. So transitively, TLBs to | |
2705 | * old page will be flushed before it can be reused. | |
2706 | */ | |
edc315fd | 2707 | page_remove_rmap(old_page); |
945754a1 NP |
2708 | } |
2709 | ||
1da177e4 LT |
2710 | /* Free the old page.. */ |
2711 | new_page = old_page; | |
f33ea7f4 | 2712 | ret |= VM_FAULT_WRITE; |
8a9f3ccd BS |
2713 | } else |
2714 | mem_cgroup_uncharge_page(new_page); | |
2715 | ||
920fc356 HD |
2716 | if (new_page) |
2717 | page_cache_release(new_page); | |
65500d23 | 2718 | unlock: |
8f4e2101 | 2719 | pte_unmap_unlock(page_table, ptl); |
e15f8c01 ML |
2720 | if (old_page) { |
2721 | /* | |
2722 | * Don't let another task, with possibly unlocked vma, | |
2723 | * keep the mlocked page. | |
2724 | */ | |
2725 | if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) { | |
2726 | lock_page(old_page); /* LRU manipulation */ | |
2727 | munlock_vma_page(old_page); | |
2728 | unlock_page(old_page); | |
2729 | } | |
2730 | page_cache_release(old_page); | |
2731 | } | |
f33ea7f4 | 2732 | return ret; |
8a9f3ccd | 2733 | oom_free_new: |
6dbf6d3b | 2734 | page_cache_release(new_page); |
65500d23 | 2735 | oom: |
b827e496 NP |
2736 | if (old_page) { |
2737 | if (page_mkwrite) { | |
2738 | unlock_page(old_page); | |
2739 | page_cache_release(old_page); | |
2740 | } | |
920fc356 | 2741 | page_cache_release(old_page); |
b827e496 | 2742 | } |
1da177e4 | 2743 | return VM_FAULT_OOM; |
9637a5ef DH |
2744 | |
2745 | unwritable_page: | |
2746 | page_cache_release(old_page); | |
c2ec175c | 2747 | return ret; |
1da177e4 LT |
2748 | } |
2749 | ||
97a89413 | 2750 | static void unmap_mapping_range_vma(struct vm_area_struct *vma, |
1da177e4 LT |
2751 | unsigned long start_addr, unsigned long end_addr, |
2752 | struct zap_details *details) | |
2753 | { | |
97a89413 | 2754 | zap_page_range(vma, start_addr, end_addr - start_addr, details); |
1da177e4 LT |
2755 | } |
2756 | ||
2757 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, | |
2758 | struct zap_details *details) | |
2759 | { | |
2760 | struct vm_area_struct *vma; | |
2761 | struct prio_tree_iter iter; | |
2762 | pgoff_t vba, vea, zba, zea; | |
2763 | ||
1da177e4 LT |
2764 | vma_prio_tree_foreach(vma, &iter, root, |
2765 | details->first_index, details->last_index) { | |
1da177e4 LT |
2766 | |
2767 | vba = vma->vm_pgoff; | |
2768 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; | |
2769 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ | |
2770 | zba = details->first_index; | |
2771 | if (zba < vba) | |
2772 | zba = vba; | |
2773 | zea = details->last_index; | |
2774 | if (zea > vea) | |
2775 | zea = vea; | |
2776 | ||
97a89413 | 2777 | unmap_mapping_range_vma(vma, |
1da177e4 LT |
2778 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, |
2779 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
97a89413 | 2780 | details); |
1da177e4 LT |
2781 | } |
2782 | } | |
2783 | ||
2784 | static inline void unmap_mapping_range_list(struct list_head *head, | |
2785 | struct zap_details *details) | |
2786 | { | |
2787 | struct vm_area_struct *vma; | |
2788 | ||
2789 | /* | |
2790 | * In nonlinear VMAs there is no correspondence between virtual address | |
2791 | * offset and file offset. So we must perform an exhaustive search | |
2792 | * across *all* the pages in each nonlinear VMA, not just the pages | |
2793 | * whose virtual address lies outside the file truncation point. | |
2794 | */ | |
1da177e4 | 2795 | list_for_each_entry(vma, head, shared.vm_set.list) { |
1da177e4 | 2796 | details->nonlinear_vma = vma; |
97a89413 | 2797 | unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details); |
1da177e4 LT |
2798 | } |
2799 | } | |
2800 | ||
2801 | /** | |
72fd4a35 | 2802 | * 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 | 2803 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
2804 | * @holebegin: byte in first page to unmap, relative to the start of |
2805 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
25d9e2d1 | 2806 | * boundary. Note that this is different from truncate_pagecache(), which |
1da177e4 LT |
2807 | * must keep the partial page. In contrast, we must get rid of |
2808 | * partial pages. | |
2809 | * @holelen: size of prospective hole in bytes. This will be rounded | |
2810 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
2811 | * end of the file. | |
2812 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
2813 | * but 0 when invalidating pagecache, don't throw away private data. | |
2814 | */ | |
2815 | void unmap_mapping_range(struct address_space *mapping, | |
2816 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
2817 | { | |
2818 | struct zap_details details; | |
2819 | pgoff_t hba = holebegin >> PAGE_SHIFT; | |
2820 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2821 | ||
2822 | /* Check for overflow. */ | |
2823 | if (sizeof(holelen) > sizeof(hlen)) { | |
2824 | long long holeend = | |
2825 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2826 | if (holeend & ~(long long)ULONG_MAX) | |
2827 | hlen = ULONG_MAX - hba + 1; | |
2828 | } | |
2829 | ||
2830 | details.check_mapping = even_cows? NULL: mapping; | |
2831 | details.nonlinear_vma = NULL; | |
2832 | details.first_index = hba; | |
2833 | details.last_index = hba + hlen - 1; | |
2834 | if (details.last_index < details.first_index) | |
2835 | details.last_index = ULONG_MAX; | |
1da177e4 | 2836 | |
1da177e4 | 2837 | |
3d48ae45 | 2838 | mutex_lock(&mapping->i_mmap_mutex); |
1da177e4 LT |
2839 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) |
2840 | unmap_mapping_range_tree(&mapping->i_mmap, &details); | |
2841 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) | |
2842 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); | |
3d48ae45 | 2843 | mutex_unlock(&mapping->i_mmap_mutex); |
1da177e4 LT |
2844 | } |
2845 | EXPORT_SYMBOL(unmap_mapping_range); | |
2846 | ||
1da177e4 | 2847 | /* |
8f4e2101 HD |
2848 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2849 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2850 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2851 | */ |
65500d23 HD |
2852 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2853 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 2854 | unsigned int flags, pte_t orig_pte) |
1da177e4 | 2855 | { |
8f4e2101 | 2856 | spinlock_t *ptl; |
4969c119 | 2857 | struct page *page, *swapcache = NULL; |
65500d23 | 2858 | swp_entry_t entry; |
1da177e4 | 2859 | pte_t pte; |
d065bd81 | 2860 | int locked; |
56039efa | 2861 | struct mem_cgroup *ptr; |
ad8c2ee8 | 2862 | int exclusive = 0; |
83c54070 | 2863 | int ret = 0; |
1da177e4 | 2864 | |
4c21e2f2 | 2865 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
8f4e2101 | 2866 | goto out; |
65500d23 HD |
2867 | |
2868 | entry = pte_to_swp_entry(orig_pte); | |
d1737fdb AK |
2869 | if (unlikely(non_swap_entry(entry))) { |
2870 | if (is_migration_entry(entry)) { | |
2871 | migration_entry_wait(mm, pmd, address); | |
2872 | } else if (is_hwpoison_entry(entry)) { | |
2873 | ret = VM_FAULT_HWPOISON; | |
2874 | } else { | |
2875 | print_bad_pte(vma, address, orig_pte, NULL); | |
d99be1a8 | 2876 | ret = VM_FAULT_SIGBUS; |
d1737fdb | 2877 | } |
0697212a CL |
2878 | goto out; |
2879 | } | |
0ff92245 | 2880 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2881 | page = lookup_swap_cache(entry); |
2882 | if (!page) { | |
a5c9b696 | 2883 | grab_swap_token(mm); /* Contend for token _before_ read-in */ |
02098fea HD |
2884 | page = swapin_readahead(entry, |
2885 | GFP_HIGHUSER_MOVABLE, vma, address); | |
1da177e4 LT |
2886 | if (!page) { |
2887 | /* | |
8f4e2101 HD |
2888 | * Back out if somebody else faulted in this pte |
2889 | * while we released the pte lock. | |
1da177e4 | 2890 | */ |
8f4e2101 | 2891 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2892 | if (likely(pte_same(*page_table, orig_pte))) |
2893 | ret = VM_FAULT_OOM; | |
0ff92245 | 2894 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2895 | goto unlock; |
1da177e4 LT |
2896 | } |
2897 | ||
2898 | /* Had to read the page from swap area: Major fault */ | |
2899 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2900 | count_vm_event(PGMAJFAULT); |
456f998e | 2901 | mem_cgroup_count_vm_event(mm, PGMAJFAULT); |
d1737fdb | 2902 | } else if (PageHWPoison(page)) { |
71f72525 WF |
2903 | /* |
2904 | * hwpoisoned dirty swapcache pages are kept for killing | |
2905 | * owner processes (which may be unknown at hwpoison time) | |
2906 | */ | |
d1737fdb AK |
2907 | ret = VM_FAULT_HWPOISON; |
2908 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); | |
4779cb31 | 2909 | goto out_release; |
1da177e4 LT |
2910 | } |
2911 | ||
d065bd81 | 2912 | locked = lock_page_or_retry(page, mm, flags); |
073e587e | 2913 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
d065bd81 ML |
2914 | if (!locked) { |
2915 | ret |= VM_FAULT_RETRY; | |
2916 | goto out_release; | |
2917 | } | |
073e587e | 2918 | |
4969c119 | 2919 | /* |
31c4a3d3 HD |
2920 | * Make sure try_to_free_swap or reuse_swap_page or swapoff did not |
2921 | * release the swapcache from under us. The page pin, and pte_same | |
2922 | * test below, are not enough to exclude that. Even if it is still | |
2923 | * swapcache, we need to check that the page's swap has not changed. | |
4969c119 | 2924 | */ |
31c4a3d3 | 2925 | if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val)) |
4969c119 AA |
2926 | goto out_page; |
2927 | ||
2928 | if (ksm_might_need_to_copy(page, vma, address)) { | |
2929 | swapcache = page; | |
2930 | page = ksm_does_need_to_copy(page, vma, address); | |
2931 | ||
2932 | if (unlikely(!page)) { | |
2933 | ret = VM_FAULT_OOM; | |
2934 | page = swapcache; | |
2935 | swapcache = NULL; | |
2936 | goto out_page; | |
2937 | } | |
5ad64688 HD |
2938 | } |
2939 | ||
2c26fdd7 | 2940 | if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) { |
8a9f3ccd | 2941 | ret = VM_FAULT_OOM; |
bc43f75c | 2942 | goto out_page; |
8a9f3ccd BS |
2943 | } |
2944 | ||
1da177e4 | 2945 | /* |
8f4e2101 | 2946 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 2947 | */ |
8f4e2101 | 2948 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
9e9bef07 | 2949 | if (unlikely(!pte_same(*page_table, orig_pte))) |
b8107480 | 2950 | goto out_nomap; |
b8107480 KK |
2951 | |
2952 | if (unlikely(!PageUptodate(page))) { | |
2953 | ret = VM_FAULT_SIGBUS; | |
2954 | goto out_nomap; | |
1da177e4 LT |
2955 | } |
2956 | ||
8c7c6e34 KH |
2957 | /* |
2958 | * The page isn't present yet, go ahead with the fault. | |
2959 | * | |
2960 | * Be careful about the sequence of operations here. | |
2961 | * To get its accounting right, reuse_swap_page() must be called | |
2962 | * while the page is counted on swap but not yet in mapcount i.e. | |
2963 | * before page_add_anon_rmap() and swap_free(); try_to_free_swap() | |
2964 | * must be called after the swap_free(), or it will never succeed. | |
03f3c433 KH |
2965 | * Because delete_from_swap_page() may be called by reuse_swap_page(), |
2966 | * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry | |
2967 | * in page->private. In this case, a record in swap_cgroup is silently | |
2968 | * discarded at swap_free(). | |
8c7c6e34 | 2969 | */ |
1da177e4 | 2970 | |
34e55232 | 2971 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
b084d435 | 2972 | dec_mm_counter_fast(mm, MM_SWAPENTS); |
1da177e4 | 2973 | pte = mk_pte(page, vma->vm_page_prot); |
30c9f3a9 | 2974 | if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) { |
1da177e4 | 2975 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); |
30c9f3a9 | 2976 | flags &= ~FAULT_FLAG_WRITE; |
9a5b489b | 2977 | ret |= VM_FAULT_WRITE; |
ad8c2ee8 | 2978 | exclusive = 1; |
1da177e4 | 2979 | } |
1da177e4 LT |
2980 | flush_icache_page(vma, page); |
2981 | set_pte_at(mm, address, page_table, pte); | |
ad8c2ee8 | 2982 | do_page_add_anon_rmap(page, vma, address, exclusive); |
03f3c433 KH |
2983 | /* It's better to call commit-charge after rmap is established */ |
2984 | mem_cgroup_commit_charge_swapin(page, ptr); | |
1da177e4 | 2985 | |
c475a8ab | 2986 | swap_free(entry); |
b291f000 | 2987 | if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) |
a2c43eed | 2988 | try_to_free_swap(page); |
c475a8ab | 2989 | unlock_page(page); |
4969c119 AA |
2990 | if (swapcache) { |
2991 | /* | |
2992 | * Hold the lock to avoid the swap entry to be reused | |
2993 | * until we take the PT lock for the pte_same() check | |
2994 | * (to avoid false positives from pte_same). For | |
2995 | * further safety release the lock after the swap_free | |
2996 | * so that the swap count won't change under a | |
2997 | * parallel locked swapcache. | |
2998 | */ | |
2999 | unlock_page(swapcache); | |
3000 | page_cache_release(swapcache); | |
3001 | } | |
c475a8ab | 3002 | |
30c9f3a9 | 3003 | if (flags & FAULT_FLAG_WRITE) { |
61469f1d HD |
3004 | ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); |
3005 | if (ret & VM_FAULT_ERROR) | |
3006 | ret &= VM_FAULT_ERROR; | |
1da177e4 LT |
3007 | goto out; |
3008 | } | |
3009 | ||
3010 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 3011 | update_mmu_cache(vma, address, page_table); |
65500d23 | 3012 | unlock: |
8f4e2101 | 3013 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
3014 | out: |
3015 | return ret; | |
b8107480 | 3016 | out_nomap: |
7a81b88c | 3017 | mem_cgroup_cancel_charge_swapin(ptr); |
8f4e2101 | 3018 | pte_unmap_unlock(page_table, ptl); |
bc43f75c | 3019 | out_page: |
b8107480 | 3020 | unlock_page(page); |
4779cb31 | 3021 | out_release: |
b8107480 | 3022 | page_cache_release(page); |
4969c119 AA |
3023 | if (swapcache) { |
3024 | unlock_page(swapcache); | |
3025 | page_cache_release(swapcache); | |
3026 | } | |
65500d23 | 3027 | return ret; |
1da177e4 LT |
3028 | } |
3029 | ||
320b2b8d | 3030 | /* |
8ca3eb08 LT |
3031 | * This is like a special single-page "expand_{down|up}wards()", |
3032 | * except we must first make sure that 'address{-|+}PAGE_SIZE' | |
320b2b8d | 3033 | * doesn't hit another vma. |
320b2b8d LT |
3034 | */ |
3035 | static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address) | |
3036 | { | |
3037 | address &= PAGE_MASK; | |
3038 | if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) { | |
0e8e50e2 LT |
3039 | struct vm_area_struct *prev = vma->vm_prev; |
3040 | ||
3041 | /* | |
3042 | * Is there a mapping abutting this one below? | |
3043 | * | |
3044 | * That's only ok if it's the same stack mapping | |
3045 | * that has gotten split.. | |
3046 | */ | |
3047 | if (prev && prev->vm_end == address) | |
3048 | return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; | |
320b2b8d | 3049 | |
d05f3169 | 3050 | expand_downwards(vma, address - PAGE_SIZE); |
320b2b8d | 3051 | } |
8ca3eb08 LT |
3052 | if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { |
3053 | struct vm_area_struct *next = vma->vm_next; | |
3054 | ||
3055 | /* As VM_GROWSDOWN but s/below/above/ */ | |
3056 | if (next && next->vm_start == address + PAGE_SIZE) | |
3057 | return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM; | |
3058 | ||
3059 | expand_upwards(vma, address + PAGE_SIZE); | |
3060 | } | |
320b2b8d LT |
3061 | return 0; |
3062 | } | |
3063 | ||
1da177e4 | 3064 | /* |
8f4e2101 HD |
3065 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
3066 | * but allow concurrent faults), and pte mapped but not yet locked. | |
3067 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 3068 | */ |
65500d23 HD |
3069 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
3070 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 3071 | unsigned int flags) |
1da177e4 | 3072 | { |
8f4e2101 HD |
3073 | struct page *page; |
3074 | spinlock_t *ptl; | |
1da177e4 | 3075 | pte_t entry; |
1da177e4 | 3076 | |
11ac5524 LT |
3077 | pte_unmap(page_table); |
3078 | ||
3079 | /* Check if we need to add a guard page to the stack */ | |
3080 | if (check_stack_guard_page(vma, address) < 0) | |
320b2b8d LT |
3081 | return VM_FAULT_SIGBUS; |
3082 | ||
11ac5524 | 3083 | /* Use the zero-page for reads */ |
62eede62 HD |
3084 | if (!(flags & FAULT_FLAG_WRITE)) { |
3085 | entry = pte_mkspecial(pfn_pte(my_zero_pfn(address), | |
3086 | vma->vm_page_prot)); | |
11ac5524 | 3087 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
a13ea5b7 HD |
3088 | if (!pte_none(*page_table)) |
3089 | goto unlock; | |
3090 | goto setpte; | |
3091 | } | |
3092 | ||
557ed1fa | 3093 | /* Allocate our own private page. */ |
557ed1fa NP |
3094 | if (unlikely(anon_vma_prepare(vma))) |
3095 | goto oom; | |
3096 | page = alloc_zeroed_user_highpage_movable(vma, address); | |
3097 | if (!page) | |
3098 | goto oom; | |
0ed361de | 3099 | __SetPageUptodate(page); |
8f4e2101 | 3100 | |
2c26fdd7 | 3101 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
3102 | goto oom_free_page; |
3103 | ||
557ed1fa | 3104 | entry = mk_pte(page, vma->vm_page_prot); |
1ac0cb5d HD |
3105 | if (vma->vm_flags & VM_WRITE) |
3106 | entry = pte_mkwrite(pte_mkdirty(entry)); | |
1da177e4 | 3107 | |
557ed1fa | 3108 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1c2fb7a4 | 3109 | if (!pte_none(*page_table)) |
557ed1fa | 3110 | goto release; |
9ba69294 | 3111 | |
34e55232 | 3112 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
557ed1fa | 3113 | page_add_new_anon_rmap(page, vma, address); |
a13ea5b7 | 3114 | setpte: |
65500d23 | 3115 | set_pte_at(mm, address, page_table, entry); |
1da177e4 LT |
3116 | |
3117 | /* No need to invalidate - it was non-present before */ | |
4b3073e1 | 3118 | update_mmu_cache(vma, address, page_table); |
65500d23 | 3119 | unlock: |
8f4e2101 | 3120 | pte_unmap_unlock(page_table, ptl); |
83c54070 | 3121 | return 0; |
8f4e2101 | 3122 | release: |
8a9f3ccd | 3123 | mem_cgroup_uncharge_page(page); |
8f4e2101 HD |
3124 | page_cache_release(page); |
3125 | goto unlock; | |
8a9f3ccd | 3126 | oom_free_page: |
6dbf6d3b | 3127 | page_cache_release(page); |
65500d23 | 3128 | oom: |
1da177e4 LT |
3129 | return VM_FAULT_OOM; |
3130 | } | |
3131 | ||
3132 | /* | |
54cb8821 | 3133 | * __do_fault() tries to create a new page mapping. It aggressively |
1da177e4 | 3134 | * tries to share with existing pages, but makes a separate copy if |
54cb8821 NP |
3135 | * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid |
3136 | * the next page fault. | |
1da177e4 LT |
3137 | * |
3138 | * As this is called only for pages that do not currently exist, we | |
3139 | * do not need to flush old virtual caches or the TLB. | |
3140 | * | |
8f4e2101 | 3141 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
16abfa08 | 3142 | * but allow concurrent faults), and pte neither mapped nor locked. |
8f4e2101 | 3143 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
1da177e4 | 3144 | */ |
54cb8821 | 3145 | static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
16abfa08 | 3146 | unsigned long address, pmd_t *pmd, |
54cb8821 | 3147 | pgoff_t pgoff, unsigned int flags, pte_t orig_pte) |
1da177e4 | 3148 | { |
16abfa08 | 3149 | pte_t *page_table; |
8f4e2101 | 3150 | spinlock_t *ptl; |
d0217ac0 | 3151 | struct page *page; |
1d65f86d | 3152 | struct page *cow_page; |
1da177e4 | 3153 | pte_t entry; |
1da177e4 | 3154 | int anon = 0; |
d08b3851 | 3155 | struct page *dirty_page = NULL; |
d0217ac0 NP |
3156 | struct vm_fault vmf; |
3157 | int ret; | |
a200ee18 | 3158 | int page_mkwrite = 0; |
54cb8821 | 3159 | |
1d65f86d KH |
3160 | /* |
3161 | * If we do COW later, allocate page befor taking lock_page() | |
3162 | * on the file cache page. This will reduce lock holding time. | |
3163 | */ | |
3164 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { | |
3165 | ||
3166 | if (unlikely(anon_vma_prepare(vma))) | |
3167 | return VM_FAULT_OOM; | |
3168 | ||
3169 | cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
3170 | if (!cow_page) | |
3171 | return VM_FAULT_OOM; | |
3172 | ||
3173 | if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) { | |
3174 | page_cache_release(cow_page); | |
3175 | return VM_FAULT_OOM; | |
3176 | } | |
3177 | } else | |
3178 | cow_page = NULL; | |
3179 | ||
d0217ac0 NP |
3180 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); |
3181 | vmf.pgoff = pgoff; | |
3182 | vmf.flags = flags; | |
3183 | vmf.page = NULL; | |
1da177e4 | 3184 | |
3c18ddd1 | 3185 | ret = vma->vm_ops->fault(vma, &vmf); |
d065bd81 ML |
3186 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | |
3187 | VM_FAULT_RETRY))) | |
1d65f86d | 3188 | goto uncharge_out; |
1da177e4 | 3189 | |
a3b947ea AK |
3190 | if (unlikely(PageHWPoison(vmf.page))) { |
3191 | if (ret & VM_FAULT_LOCKED) | |
3192 | unlock_page(vmf.page); | |
1d65f86d KH |
3193 | ret = VM_FAULT_HWPOISON; |
3194 | goto uncharge_out; | |
a3b947ea AK |
3195 | } |
3196 | ||
d00806b1 | 3197 | /* |
d0217ac0 | 3198 | * For consistency in subsequent calls, make the faulted page always |
d00806b1 NP |
3199 | * locked. |
3200 | */ | |
83c54070 | 3201 | if (unlikely(!(ret & VM_FAULT_LOCKED))) |
d0217ac0 | 3202 | lock_page(vmf.page); |
54cb8821 | 3203 | else |
d0217ac0 | 3204 | VM_BUG_ON(!PageLocked(vmf.page)); |
d00806b1 | 3205 | |
1da177e4 LT |
3206 | /* |
3207 | * Should we do an early C-O-W break? | |
3208 | */ | |
d0217ac0 | 3209 | page = vmf.page; |
54cb8821 | 3210 | if (flags & FAULT_FLAG_WRITE) { |
9637a5ef | 3211 | if (!(vma->vm_flags & VM_SHARED)) { |
1d65f86d | 3212 | page = cow_page; |
54cb8821 | 3213 | anon = 1; |
d0217ac0 | 3214 | copy_user_highpage(page, vmf.page, address, vma); |
0ed361de | 3215 | __SetPageUptodate(page); |
9637a5ef | 3216 | } else { |
54cb8821 NP |
3217 | /* |
3218 | * If the page will be shareable, see if the backing | |
9637a5ef | 3219 | * address space wants to know that the page is about |
54cb8821 NP |
3220 | * to become writable |
3221 | */ | |
69676147 | 3222 | if (vma->vm_ops->page_mkwrite) { |
c2ec175c NP |
3223 | int tmp; |
3224 | ||
69676147 | 3225 | unlock_page(page); |
b827e496 | 3226 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; |
c2ec175c NP |
3227 | tmp = vma->vm_ops->page_mkwrite(vma, &vmf); |
3228 | if (unlikely(tmp & | |
3229 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { | |
3230 | ret = tmp; | |
b827e496 | 3231 | goto unwritable_page; |
d0217ac0 | 3232 | } |
b827e496 NP |
3233 | if (unlikely(!(tmp & VM_FAULT_LOCKED))) { |
3234 | lock_page(page); | |
3235 | if (!page->mapping) { | |
3236 | ret = 0; /* retry the fault */ | |
3237 | unlock_page(page); | |
3238 | goto unwritable_page; | |
3239 | } | |
3240 | } else | |
3241 | VM_BUG_ON(!PageLocked(page)); | |
a200ee18 | 3242 | page_mkwrite = 1; |
9637a5ef DH |
3243 | } |
3244 | } | |
54cb8821 | 3245 | |
1da177e4 LT |
3246 | } |
3247 | ||
8f4e2101 | 3248 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
3249 | |
3250 | /* | |
3251 | * This silly early PAGE_DIRTY setting removes a race | |
3252 | * due to the bad i386 page protection. But it's valid | |
3253 | * for other architectures too. | |
3254 | * | |
30c9f3a9 | 3255 | * Note that if FAULT_FLAG_WRITE is set, we either now have |
1da177e4 LT |
3256 | * an exclusive copy of the page, or this is a shared mapping, |
3257 | * so we can make it writable and dirty to avoid having to | |
3258 | * handle that later. | |
3259 | */ | |
3260 | /* Only go through if we didn't race with anybody else... */ | |
1c2fb7a4 | 3261 | if (likely(pte_same(*page_table, orig_pte))) { |
d00806b1 NP |
3262 | flush_icache_page(vma, page); |
3263 | entry = mk_pte(page, vma->vm_page_prot); | |
54cb8821 | 3264 | if (flags & FAULT_FLAG_WRITE) |
1da177e4 | 3265 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
1da177e4 | 3266 | if (anon) { |
34e55232 | 3267 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
64d6519d | 3268 | page_add_new_anon_rmap(page, vma, address); |
f57e88a8 | 3269 | } else { |
34e55232 | 3270 | inc_mm_counter_fast(mm, MM_FILEPAGES); |
d00806b1 | 3271 | page_add_file_rmap(page); |
54cb8821 | 3272 | if (flags & FAULT_FLAG_WRITE) { |
d00806b1 | 3273 | dirty_page = page; |
d08b3851 PZ |
3274 | get_page(dirty_page); |
3275 | } | |
4294621f | 3276 | } |
64d6519d | 3277 | set_pte_at(mm, address, page_table, entry); |
d00806b1 NP |
3278 | |
3279 | /* no need to invalidate: a not-present page won't be cached */ | |
4b3073e1 | 3280 | update_mmu_cache(vma, address, page_table); |
1da177e4 | 3281 | } else { |
1d65f86d KH |
3282 | if (cow_page) |
3283 | mem_cgroup_uncharge_page(cow_page); | |
d00806b1 NP |
3284 | if (anon) |
3285 | page_cache_release(page); | |
3286 | else | |
54cb8821 | 3287 | anon = 1; /* no anon but release faulted_page */ |
1da177e4 LT |
3288 | } |
3289 | ||
8f4e2101 | 3290 | pte_unmap_unlock(page_table, ptl); |
d00806b1 | 3291 | |
b827e496 NP |
3292 | if (dirty_page) { |
3293 | struct address_space *mapping = page->mapping; | |
8f7b3d15 | 3294 | |
b827e496 NP |
3295 | if (set_page_dirty(dirty_page)) |
3296 | page_mkwrite = 1; | |
3297 | unlock_page(dirty_page); | |
d08b3851 | 3298 | put_page(dirty_page); |
b827e496 NP |
3299 | if (page_mkwrite && mapping) { |
3300 | /* | |
3301 | * Some device drivers do not set page.mapping but still | |
3302 | * dirty their pages | |
3303 | */ | |
3304 | balance_dirty_pages_ratelimited(mapping); | |
3305 | } | |
3306 | ||
3307 | /* file_update_time outside page_lock */ | |
3308 | if (vma->vm_file) | |
3309 | file_update_time(vma->vm_file); | |
3310 | } else { | |
3311 | unlock_page(vmf.page); | |
3312 | if (anon) | |
3313 | page_cache_release(vmf.page); | |
d08b3851 | 3314 | } |
d00806b1 | 3315 | |
83c54070 | 3316 | return ret; |
b827e496 NP |
3317 | |
3318 | unwritable_page: | |
3319 | page_cache_release(page); | |
3320 | return ret; | |
1d65f86d KH |
3321 | uncharge_out: |
3322 | /* fs's fault handler get error */ | |
3323 | if (cow_page) { | |
3324 | mem_cgroup_uncharge_page(cow_page); | |
3325 | page_cache_release(cow_page); | |
3326 | } | |
3327 | return ret; | |
54cb8821 | 3328 | } |
d00806b1 | 3329 | |
54cb8821 NP |
3330 | static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
3331 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 3332 | unsigned int flags, pte_t orig_pte) |
54cb8821 NP |
3333 | { |
3334 | pgoff_t pgoff = (((address & PAGE_MASK) | |
0da7e01f | 3335 | - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
54cb8821 | 3336 | |
16abfa08 HD |
3337 | pte_unmap(page_table); |
3338 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); | |
54cb8821 NP |
3339 | } |
3340 | ||
1da177e4 LT |
3341 | /* |
3342 | * Fault of a previously existing named mapping. Repopulate the pte | |
3343 | * from the encoded file_pte if possible. This enables swappable | |
3344 | * nonlinear vmas. | |
8f4e2101 HD |
3345 | * |
3346 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
3347 | * but allow concurrent faults), and pte mapped but not yet locked. | |
3348 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 3349 | */ |
d0217ac0 | 3350 | static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
65500d23 | 3351 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
30c9f3a9 | 3352 | unsigned int flags, pte_t orig_pte) |
1da177e4 | 3353 | { |
65500d23 | 3354 | pgoff_t pgoff; |
1da177e4 | 3355 | |
30c9f3a9 LT |
3356 | flags |= FAULT_FLAG_NONLINEAR; |
3357 | ||
4c21e2f2 | 3358 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
83c54070 | 3359 | return 0; |
1da177e4 | 3360 | |
2509ef26 | 3361 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { |
65500d23 HD |
3362 | /* |
3363 | * Page table corrupted: show pte and kill process. | |
3364 | */ | |
3dc14741 | 3365 | print_bad_pte(vma, address, orig_pte, NULL); |
d99be1a8 | 3366 | return VM_FAULT_SIGBUS; |
65500d23 | 3367 | } |
65500d23 HD |
3368 | |
3369 | pgoff = pte_to_pgoff(orig_pte); | |
16abfa08 | 3370 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); |
1da177e4 LT |
3371 | } |
3372 | ||
3373 | /* | |
3374 | * These routines also need to handle stuff like marking pages dirty | |
3375 | * and/or accessed for architectures that don't do it in hardware (most | |
3376 | * RISC architectures). The early dirtying is also good on the i386. | |
3377 | * | |
3378 | * There is also a hook called "update_mmu_cache()" that architectures | |
3379 | * with external mmu caches can use to update those (ie the Sparc or | |
3380 | * PowerPC hashed page tables that act as extended TLBs). | |
3381 | * | |
c74df32c HD |
3382 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
3383 | * but allow concurrent faults), and pte mapped but not yet locked. | |
3384 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 3385 | */ |
71e3aac0 AA |
3386 | int handle_pte_fault(struct mm_struct *mm, |
3387 | struct vm_area_struct *vma, unsigned long address, | |
3388 | pte_t *pte, pmd_t *pmd, unsigned int flags) | |
1da177e4 LT |
3389 | { |
3390 | pte_t entry; | |
8f4e2101 | 3391 | spinlock_t *ptl; |
1da177e4 | 3392 | |
8dab5241 | 3393 | entry = *pte; |
1da177e4 | 3394 | if (!pte_present(entry)) { |
65500d23 | 3395 | if (pte_none(entry)) { |
f4b81804 | 3396 | if (vma->vm_ops) { |
3c18ddd1 | 3397 | if (likely(vma->vm_ops->fault)) |
54cb8821 | 3398 | return do_linear_fault(mm, vma, address, |
30c9f3a9 | 3399 | pte, pmd, flags, entry); |
f4b81804 JS |
3400 | } |
3401 | return do_anonymous_page(mm, vma, address, | |
30c9f3a9 | 3402 | pte, pmd, flags); |
65500d23 | 3403 | } |
1da177e4 | 3404 | if (pte_file(entry)) |
d0217ac0 | 3405 | return do_nonlinear_fault(mm, vma, address, |
30c9f3a9 | 3406 | pte, pmd, flags, entry); |
65500d23 | 3407 | return do_swap_page(mm, vma, address, |
30c9f3a9 | 3408 | pte, pmd, flags, entry); |
1da177e4 LT |
3409 | } |
3410 | ||
4c21e2f2 | 3411 | ptl = pte_lockptr(mm, pmd); |
8f4e2101 HD |
3412 | spin_lock(ptl); |
3413 | if (unlikely(!pte_same(*pte, entry))) | |
3414 | goto unlock; | |
30c9f3a9 | 3415 | if (flags & FAULT_FLAG_WRITE) { |
1da177e4 | 3416 | if (!pte_write(entry)) |
8f4e2101 HD |
3417 | return do_wp_page(mm, vma, address, |
3418 | pte, pmd, ptl, entry); | |
1da177e4 LT |
3419 | entry = pte_mkdirty(entry); |
3420 | } | |
3421 | entry = pte_mkyoung(entry); | |
30c9f3a9 | 3422 | if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) { |
4b3073e1 | 3423 | update_mmu_cache(vma, address, pte); |
1a44e149 AA |
3424 | } else { |
3425 | /* | |
3426 | * This is needed only for protection faults but the arch code | |
3427 | * is not yet telling us if this is a protection fault or not. | |
3428 | * This still avoids useless tlb flushes for .text page faults | |
3429 | * with threads. | |
3430 | */ | |
30c9f3a9 | 3431 | if (flags & FAULT_FLAG_WRITE) |
61c77326 | 3432 | flush_tlb_fix_spurious_fault(vma, address); |
1a44e149 | 3433 | } |
8f4e2101 HD |
3434 | unlock: |
3435 | pte_unmap_unlock(pte, ptl); | |
83c54070 | 3436 | return 0; |
1da177e4 LT |
3437 | } |
3438 | ||
3439 | /* | |
3440 | * By the time we get here, we already hold the mm semaphore | |
3441 | */ | |
83c54070 | 3442 | int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
d06063cc | 3443 | unsigned long address, unsigned int flags) |
1da177e4 LT |
3444 | { |
3445 | pgd_t *pgd; | |
3446 | pud_t *pud; | |
3447 | pmd_t *pmd; | |
3448 | pte_t *pte; | |
3449 | ||
3450 | __set_current_state(TASK_RUNNING); | |
3451 | ||
f8891e5e | 3452 | count_vm_event(PGFAULT); |
456f998e | 3453 | mem_cgroup_count_vm_event(mm, PGFAULT); |
1da177e4 | 3454 | |
34e55232 KH |
3455 | /* do counter updates before entering really critical section. */ |
3456 | check_sync_rss_stat(current); | |
3457 | ||
ac9b9c66 | 3458 | if (unlikely(is_vm_hugetlb_page(vma))) |
30c9f3a9 | 3459 | return hugetlb_fault(mm, vma, address, flags); |
1da177e4 | 3460 | |
1da177e4 | 3461 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
3462 | pud = pud_alloc(mm, pgd, address); |
3463 | if (!pud) | |
c74df32c | 3464 | return VM_FAULT_OOM; |
1da177e4 LT |
3465 | pmd = pmd_alloc(mm, pud, address); |
3466 | if (!pmd) | |
c74df32c | 3467 | return VM_FAULT_OOM; |
71e3aac0 AA |
3468 | if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) { |
3469 | if (!vma->vm_ops) | |
3470 | return do_huge_pmd_anonymous_page(mm, vma, address, | |
3471 | pmd, flags); | |
3472 | } else { | |
3473 | pmd_t orig_pmd = *pmd; | |
3474 | barrier(); | |
3475 | if (pmd_trans_huge(orig_pmd)) { | |
3476 | if (flags & FAULT_FLAG_WRITE && | |
3477 | !pmd_write(orig_pmd) && | |
3478 | !pmd_trans_splitting(orig_pmd)) | |
3479 | return do_huge_pmd_wp_page(mm, vma, address, | |
3480 | pmd, orig_pmd); | |
3481 | return 0; | |
3482 | } | |
3483 | } | |
3484 | ||
3485 | /* | |
3486 | * Use __pte_alloc instead of pte_alloc_map, because we can't | |
3487 | * run pte_offset_map on the pmd, if an huge pmd could | |
3488 | * materialize from under us from a different thread. | |
3489 | */ | |
cc03638d | 3490 | if (unlikely(pmd_none(*pmd)) && __pte_alloc(mm, vma, pmd, address)) |
c74df32c | 3491 | return VM_FAULT_OOM; |
71e3aac0 AA |
3492 | /* if an huge pmd materialized from under us just retry later */ |
3493 | if (unlikely(pmd_trans_huge(*pmd))) | |
3494 | return 0; | |
3495 | /* | |
3496 | * A regular pmd is established and it can't morph into a huge pmd | |
3497 | * from under us anymore at this point because we hold the mmap_sem | |
3498 | * read mode and khugepaged takes it in write mode. So now it's | |
3499 | * safe to run pte_offset_map(). | |
3500 | */ | |
3501 | pte = pte_offset_map(pmd, address); | |
1da177e4 | 3502 | |
30c9f3a9 | 3503 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); |
1da177e4 LT |
3504 | } |
3505 | ||
3506 | #ifndef __PAGETABLE_PUD_FOLDED | |
3507 | /* | |
3508 | * Allocate page upper directory. | |
872fec16 | 3509 | * We've already handled the fast-path in-line. |
1da177e4 | 3510 | */ |
1bb3630e | 3511 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 3512 | { |
c74df32c HD |
3513 | pud_t *new = pud_alloc_one(mm, address); |
3514 | if (!new) | |
1bb3630e | 3515 | return -ENOMEM; |
1da177e4 | 3516 | |
362a61ad NP |
3517 | smp_wmb(); /* See comment in __pte_alloc */ |
3518 | ||
872fec16 | 3519 | spin_lock(&mm->page_table_lock); |
1bb3630e | 3520 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 3521 | pud_free(mm, new); |
1bb3630e HD |
3522 | else |
3523 | pgd_populate(mm, pgd, new); | |
c74df32c | 3524 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3525 | return 0; |
1da177e4 LT |
3526 | } |
3527 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
3528 | ||
3529 | #ifndef __PAGETABLE_PMD_FOLDED | |
3530 | /* | |
3531 | * Allocate page middle directory. | |
872fec16 | 3532 | * We've already handled the fast-path in-line. |
1da177e4 | 3533 | */ |
1bb3630e | 3534 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 3535 | { |
c74df32c HD |
3536 | pmd_t *new = pmd_alloc_one(mm, address); |
3537 | if (!new) | |
1bb3630e | 3538 | return -ENOMEM; |
1da177e4 | 3539 | |
362a61ad NP |
3540 | smp_wmb(); /* See comment in __pte_alloc */ |
3541 | ||
872fec16 | 3542 | spin_lock(&mm->page_table_lock); |
1da177e4 | 3543 | #ifndef __ARCH_HAS_4LEVEL_HACK |
1bb3630e | 3544 | if (pud_present(*pud)) /* Another has populated it */ |
5e541973 | 3545 | pmd_free(mm, new); |
1bb3630e HD |
3546 | else |
3547 | pud_populate(mm, pud, new); | |
1da177e4 | 3548 | #else |
1bb3630e | 3549 | if (pgd_present(*pud)) /* Another has populated it */ |
5e541973 | 3550 | pmd_free(mm, new); |
1bb3630e HD |
3551 | else |
3552 | pgd_populate(mm, pud, new); | |
1da177e4 | 3553 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 3554 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3555 | return 0; |
e0f39591 | 3556 | } |
1da177e4 LT |
3557 | #endif /* __PAGETABLE_PMD_FOLDED */ |
3558 | ||
3559 | int make_pages_present(unsigned long addr, unsigned long end) | |
3560 | { | |
3561 | int ret, len, write; | |
3562 | struct vm_area_struct * vma; | |
3563 | ||
3564 | vma = find_vma(current->mm, addr); | |
3565 | if (!vma) | |
a477097d | 3566 | return -ENOMEM; |
5ecfda04 ML |
3567 | /* |
3568 | * We want to touch writable mappings with a write fault in order | |
3569 | * to break COW, except for shared mappings because these don't COW | |
3570 | * and we would not want to dirty them for nothing. | |
3571 | */ | |
3572 | write = (vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE; | |
5bcb28b1 ES |
3573 | BUG_ON(addr >= end); |
3574 | BUG_ON(end > vma->vm_end); | |
68e116a3 | 3575 | len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; |
1da177e4 LT |
3576 | ret = get_user_pages(current, current->mm, addr, |
3577 | len, write, 0, NULL, NULL); | |
c11d69d8 | 3578 | if (ret < 0) |
1da177e4 | 3579 | return ret; |
9978ad58 | 3580 | return ret == len ? 0 : -EFAULT; |
1da177e4 LT |
3581 | } |
3582 | ||
1da177e4 LT |
3583 | #if !defined(__HAVE_ARCH_GATE_AREA) |
3584 | ||
3585 | #if defined(AT_SYSINFO_EHDR) | |
5ce7852c | 3586 | static struct vm_area_struct gate_vma; |
1da177e4 LT |
3587 | |
3588 | static int __init gate_vma_init(void) | |
3589 | { | |
3590 | gate_vma.vm_mm = NULL; | |
3591 | gate_vma.vm_start = FIXADDR_USER_START; | |
3592 | gate_vma.vm_end = FIXADDR_USER_END; | |
b6558c4a RM |
3593 | gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; |
3594 | gate_vma.vm_page_prot = __P101; | |
f47aef55 RM |
3595 | /* |
3596 | * Make sure the vDSO gets into every core dump. | |
3597 | * Dumping its contents makes post-mortem fully interpretable later | |
3598 | * without matching up the same kernel and hardware config to see | |
3599 | * what PC values meant. | |
3600 | */ | |
3601 | gate_vma.vm_flags |= VM_ALWAYSDUMP; | |
1da177e4 LT |
3602 | return 0; |
3603 | } | |
3604 | __initcall(gate_vma_init); | |
3605 | #endif | |
3606 | ||
31db58b3 | 3607 | struct vm_area_struct *get_gate_vma(struct mm_struct *mm) |
1da177e4 LT |
3608 | { |
3609 | #ifdef AT_SYSINFO_EHDR | |
3610 | return &gate_vma; | |
3611 | #else | |
3612 | return NULL; | |
3613 | #endif | |
3614 | } | |
3615 | ||
cae5d390 | 3616 | int in_gate_area_no_mm(unsigned long addr) |
1da177e4 LT |
3617 | { |
3618 | #ifdef AT_SYSINFO_EHDR | |
3619 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) | |
3620 | return 1; | |
3621 | #endif | |
3622 | return 0; | |
3623 | } | |
3624 | ||
3625 | #endif /* __HAVE_ARCH_GATE_AREA */ | |
0ec76a11 | 3626 | |
1b36ba81 | 3627 | static int __follow_pte(struct mm_struct *mm, unsigned long address, |
f8ad0f49 JW |
3628 | pte_t **ptepp, spinlock_t **ptlp) |
3629 | { | |
3630 | pgd_t *pgd; | |
3631 | pud_t *pud; | |
3632 | pmd_t *pmd; | |
3633 | pte_t *ptep; | |
3634 | ||
3635 | pgd = pgd_offset(mm, address); | |
3636 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
3637 | goto out; | |
3638 | ||
3639 | pud = pud_offset(pgd, address); | |
3640 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
3641 | goto out; | |
3642 | ||
3643 | pmd = pmd_offset(pud, address); | |
f66055ab | 3644 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
f8ad0f49 JW |
3645 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) |
3646 | goto out; | |
3647 | ||
3648 | /* We cannot handle huge page PFN maps. Luckily they don't exist. */ | |
3649 | if (pmd_huge(*pmd)) | |
3650 | goto out; | |
3651 | ||
3652 | ptep = pte_offset_map_lock(mm, pmd, address, ptlp); | |
3653 | if (!ptep) | |
3654 | goto out; | |
3655 | if (!pte_present(*ptep)) | |
3656 | goto unlock; | |
3657 | *ptepp = ptep; | |
3658 | return 0; | |
3659 | unlock: | |
3660 | pte_unmap_unlock(ptep, *ptlp); | |
3661 | out: | |
3662 | return -EINVAL; | |
3663 | } | |
3664 | ||
1b36ba81 NK |
3665 | static inline int follow_pte(struct mm_struct *mm, unsigned long address, |
3666 | pte_t **ptepp, spinlock_t **ptlp) | |
3667 | { | |
3668 | int res; | |
3669 | ||
3670 | /* (void) is needed to make gcc happy */ | |
3671 | (void) __cond_lock(*ptlp, | |
3672 | !(res = __follow_pte(mm, address, ptepp, ptlp))); | |
3673 | return res; | |
3674 | } | |
3675 | ||
3b6748e2 JW |
3676 | /** |
3677 | * follow_pfn - look up PFN at a user virtual address | |
3678 | * @vma: memory mapping | |
3679 | * @address: user virtual address | |
3680 | * @pfn: location to store found PFN | |
3681 | * | |
3682 | * Only IO mappings and raw PFN mappings are allowed. | |
3683 | * | |
3684 | * Returns zero and the pfn at @pfn on success, -ve otherwise. | |
3685 | */ | |
3686 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, | |
3687 | unsigned long *pfn) | |
3688 | { | |
3689 | int ret = -EINVAL; | |
3690 | spinlock_t *ptl; | |
3691 | pte_t *ptep; | |
3692 | ||
3693 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
3694 | return ret; | |
3695 | ||
3696 | ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); | |
3697 | if (ret) | |
3698 | return ret; | |
3699 | *pfn = pte_pfn(*ptep); | |
3700 | pte_unmap_unlock(ptep, ptl); | |
3701 | return 0; | |
3702 | } | |
3703 | EXPORT_SYMBOL(follow_pfn); | |
3704 | ||
28b2ee20 | 3705 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
d87fe660 | 3706 | int follow_phys(struct vm_area_struct *vma, |
3707 | unsigned long address, unsigned int flags, | |
3708 | unsigned long *prot, resource_size_t *phys) | |
28b2ee20 | 3709 | { |
03668a4d | 3710 | int ret = -EINVAL; |
28b2ee20 RR |
3711 | pte_t *ptep, pte; |
3712 | spinlock_t *ptl; | |
28b2ee20 | 3713 | |
d87fe660 | 3714 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
3715 | goto out; | |
28b2ee20 | 3716 | |
03668a4d | 3717 | if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) |
d87fe660 | 3718 | goto out; |
28b2ee20 | 3719 | pte = *ptep; |
03668a4d | 3720 | |
28b2ee20 RR |
3721 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
3722 | goto unlock; | |
28b2ee20 RR |
3723 | |
3724 | *prot = pgprot_val(pte_pgprot(pte)); | |
03668a4d | 3725 | *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; |
28b2ee20 | 3726 | |
03668a4d | 3727 | ret = 0; |
28b2ee20 RR |
3728 | unlock: |
3729 | pte_unmap_unlock(ptep, ptl); | |
3730 | out: | |
d87fe660 | 3731 | return ret; |
28b2ee20 RR |
3732 | } |
3733 | ||
3734 | int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, | |
3735 | void *buf, int len, int write) | |
3736 | { | |
3737 | resource_size_t phys_addr; | |
3738 | unsigned long prot = 0; | |
2bc7273b | 3739 | void __iomem *maddr; |
28b2ee20 RR |
3740 | int offset = addr & (PAGE_SIZE-1); |
3741 | ||
d87fe660 | 3742 | if (follow_phys(vma, addr, write, &prot, &phys_addr)) |
28b2ee20 RR |
3743 | return -EINVAL; |
3744 | ||
3745 | maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); | |
3746 | if (write) | |
3747 | memcpy_toio(maddr + offset, buf, len); | |
3748 | else | |
3749 | memcpy_fromio(buf, maddr + offset, len); | |
3750 | iounmap(maddr); | |
3751 | ||
3752 | return len; | |
3753 | } | |
3754 | #endif | |
3755 | ||
0ec76a11 | 3756 | /* |
206cb636 SW |
3757 | * Access another process' address space as given in mm. If non-NULL, use the |
3758 | * given task for page fault accounting. | |
0ec76a11 | 3759 | */ |
206cb636 SW |
3760 | static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, |
3761 | unsigned long addr, void *buf, int len, int write) | |
0ec76a11 | 3762 | { |
0ec76a11 | 3763 | struct vm_area_struct *vma; |
0ec76a11 DH |
3764 | void *old_buf = buf; |
3765 | ||
0ec76a11 | 3766 | down_read(&mm->mmap_sem); |
183ff22b | 3767 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
3768 | while (len) { |
3769 | int bytes, ret, offset; | |
3770 | void *maddr; | |
28b2ee20 | 3771 | struct page *page = NULL; |
0ec76a11 DH |
3772 | |
3773 | ret = get_user_pages(tsk, mm, addr, 1, | |
3774 | write, 1, &page, &vma); | |
28b2ee20 RR |
3775 | if (ret <= 0) { |
3776 | /* | |
3777 | * Check if this is a VM_IO | VM_PFNMAP VMA, which | |
3778 | * we can access using slightly different code. | |
3779 | */ | |
3780 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
3781 | vma = find_vma(mm, addr); | |
fe936dfc | 3782 | if (!vma || vma->vm_start > addr) |
28b2ee20 RR |
3783 | break; |
3784 | if (vma->vm_ops && vma->vm_ops->access) | |
3785 | ret = vma->vm_ops->access(vma, addr, buf, | |
3786 | len, write); | |
3787 | if (ret <= 0) | |
3788 | #endif | |
3789 | break; | |
3790 | bytes = ret; | |
0ec76a11 | 3791 | } else { |
28b2ee20 RR |
3792 | bytes = len; |
3793 | offset = addr & (PAGE_SIZE-1); | |
3794 | if (bytes > PAGE_SIZE-offset) | |
3795 | bytes = PAGE_SIZE-offset; | |
3796 | ||
3797 | maddr = kmap(page); | |
3798 | if (write) { | |
3799 | copy_to_user_page(vma, page, addr, | |
3800 | maddr + offset, buf, bytes); | |
3801 | set_page_dirty_lock(page); | |
3802 | } else { | |
3803 | copy_from_user_page(vma, page, addr, | |
3804 | buf, maddr + offset, bytes); | |
3805 | } | |
3806 | kunmap(page); | |
3807 | page_cache_release(page); | |
0ec76a11 | 3808 | } |
0ec76a11 DH |
3809 | len -= bytes; |
3810 | buf += bytes; | |
3811 | addr += bytes; | |
3812 | } | |
3813 | up_read(&mm->mmap_sem); | |
0ec76a11 DH |
3814 | |
3815 | return buf - old_buf; | |
3816 | } | |
03252919 | 3817 | |
5ddd36b9 | 3818 | /** |
ae91dbfc | 3819 | * access_remote_vm - access another process' address space |
5ddd36b9 SW |
3820 | * @mm: the mm_struct of the target address space |
3821 | * @addr: start address to access | |
3822 | * @buf: source or destination buffer | |
3823 | * @len: number of bytes to transfer | |
3824 | * @write: whether the access is a write | |
3825 | * | |
3826 | * The caller must hold a reference on @mm. | |
3827 | */ | |
3828 | int access_remote_vm(struct mm_struct *mm, unsigned long addr, | |
3829 | void *buf, int len, int write) | |
3830 | { | |
3831 | return __access_remote_vm(NULL, mm, addr, buf, len, write); | |
3832 | } | |
3833 | ||
206cb636 SW |
3834 | /* |
3835 | * Access another process' address space. | |
3836 | * Source/target buffer must be kernel space, | |
3837 | * Do not walk the page table directly, use get_user_pages | |
3838 | */ | |
3839 | int access_process_vm(struct task_struct *tsk, unsigned long addr, | |
3840 | void *buf, int len, int write) | |
3841 | { | |
3842 | struct mm_struct *mm; | |
3843 | int ret; | |
3844 | ||
3845 | mm = get_task_mm(tsk); | |
3846 | if (!mm) | |
3847 | return 0; | |
3848 | ||
3849 | ret = __access_remote_vm(tsk, mm, addr, buf, len, write); | |
3850 | mmput(mm); | |
3851 | ||
3852 | return ret; | |
3853 | } | |
3854 | ||
03252919 AK |
3855 | /* |
3856 | * Print the name of a VMA. | |
3857 | */ | |
3858 | void print_vma_addr(char *prefix, unsigned long ip) | |
3859 | { | |
3860 | struct mm_struct *mm = current->mm; | |
3861 | struct vm_area_struct *vma; | |
3862 | ||
e8bff74a IM |
3863 | /* |
3864 | * Do not print if we are in atomic | |
3865 | * contexts (in exception stacks, etc.): | |
3866 | */ | |
3867 | if (preempt_count()) | |
3868 | return; | |
3869 | ||
03252919 AK |
3870 | down_read(&mm->mmap_sem); |
3871 | vma = find_vma(mm, ip); | |
3872 | if (vma && vma->vm_file) { | |
3873 | struct file *f = vma->vm_file; | |
3874 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
3875 | if (buf) { | |
3876 | char *p, *s; | |
3877 | ||
cf28b486 | 3878 | p = d_path(&f->f_path, buf, PAGE_SIZE); |
03252919 AK |
3879 | if (IS_ERR(p)) |
3880 | p = "?"; | |
3881 | s = strrchr(p, '/'); | |
3882 | if (s) | |
3883 | p = s+1; | |
3884 | printk("%s%s[%lx+%lx]", prefix, p, | |
3885 | vma->vm_start, | |
3886 | vma->vm_end - vma->vm_start); | |
3887 | free_page((unsigned long)buf); | |
3888 | } | |
3889 | } | |
3890 | up_read(¤t->mm->mmap_sem); | |
3891 | } | |
3ee1afa3 NP |
3892 | |
3893 | #ifdef CONFIG_PROVE_LOCKING | |
3894 | void might_fault(void) | |
3895 | { | |
95156f00 PZ |
3896 | /* |
3897 | * Some code (nfs/sunrpc) uses socket ops on kernel memory while | |
3898 | * holding the mmap_sem, this is safe because kernel memory doesn't | |
3899 | * get paged out, therefore we'll never actually fault, and the | |
3900 | * below annotations will generate false positives. | |
3901 | */ | |
3902 | if (segment_eq(get_fs(), KERNEL_DS)) | |
3903 | return; | |
3904 | ||
3ee1afa3 NP |
3905 | might_sleep(); |
3906 | /* | |
3907 | * it would be nicer only to annotate paths which are not under | |
3908 | * pagefault_disable, however that requires a larger audit and | |
3909 | * providing helpers like get_user_atomic. | |
3910 | */ | |
3911 | if (!in_atomic() && current->mm) | |
3912 | might_lock_read(¤t->mm->mmap_sem); | |
3913 | } | |
3914 | EXPORT_SYMBOL(might_fault); | |
3915 | #endif | |
47ad8475 AA |
3916 | |
3917 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) | |
3918 | static void clear_gigantic_page(struct page *page, | |
3919 | unsigned long addr, | |
3920 | unsigned int pages_per_huge_page) | |
3921 | { | |
3922 | int i; | |
3923 | struct page *p = page; | |
3924 | ||
3925 | might_sleep(); | |
3926 | for (i = 0; i < pages_per_huge_page; | |
3927 | i++, p = mem_map_next(p, page, i)) { | |
3928 | cond_resched(); | |
3929 | clear_user_highpage(p, addr + i * PAGE_SIZE); | |
3930 | } | |
3931 | } | |
3932 | void clear_huge_page(struct page *page, | |
3933 | unsigned long addr, unsigned int pages_per_huge_page) | |
3934 | { | |
3935 | int i; | |
3936 | ||
3937 | if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { | |
3938 | clear_gigantic_page(page, addr, pages_per_huge_page); | |
3939 | return; | |
3940 | } | |
3941 | ||
3942 | might_sleep(); | |
3943 | for (i = 0; i < pages_per_huge_page; i++) { | |
3944 | cond_resched(); | |
3945 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); | |
3946 | } | |
3947 | } | |
3948 | ||
3949 | static void copy_user_gigantic_page(struct page *dst, struct page *src, | |
3950 | unsigned long addr, | |
3951 | struct vm_area_struct *vma, | |
3952 | unsigned int pages_per_huge_page) | |
3953 | { | |
3954 | int i; | |
3955 | struct page *dst_base = dst; | |
3956 | struct page *src_base = src; | |
3957 | ||
3958 | for (i = 0; i < pages_per_huge_page; ) { | |
3959 | cond_resched(); | |
3960 | copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); | |
3961 | ||
3962 | i++; | |
3963 | dst = mem_map_next(dst, dst_base, i); | |
3964 | src = mem_map_next(src, src_base, i); | |
3965 | } | |
3966 | } | |
3967 | ||
3968 | void copy_user_huge_page(struct page *dst, struct page *src, | |
3969 | unsigned long addr, struct vm_area_struct *vma, | |
3970 | unsigned int pages_per_huge_page) | |
3971 | { | |
3972 | int i; | |
3973 | ||
3974 | if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { | |
3975 | copy_user_gigantic_page(dst, src, addr, vma, | |
3976 | pages_per_huge_page); | |
3977 | return; | |
3978 | } | |
3979 | ||
3980 | might_sleep(); | |
3981 | for (i = 0; i < pages_per_huge_page; i++) { | |
3982 | cond_resched(); | |
3983 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); | |
3984 | } | |
3985 | } | |
3986 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ |