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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/memory.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * demand-loading started 01.12.91 - seems it is high on the list of | |
9 | * things wanted, and it should be easy to implement. - Linus | |
10 | */ | |
11 | ||
12 | /* | |
13 | * Ok, demand-loading was easy, shared pages a little bit tricker. Shared | |
14 | * pages started 02.12.91, seems to work. - Linus. | |
15 | * | |
16 | * Tested sharing by executing about 30 /bin/sh: under the old kernel it | |
17 | * would have taken more than the 6M I have free, but it worked well as | |
18 | * far as I could see. | |
19 | * | |
20 | * Also corrected some "invalidate()"s - I wasn't doing enough of them. | |
21 | */ | |
22 | ||
23 | /* | |
24 | * Real VM (paging to/from disk) started 18.12.91. Much more work and | |
25 | * thought has to go into this. Oh, well.. | |
26 | * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. | |
27 | * Found it. Everything seems to work now. | |
28 | * 20.12.91 - Ok, making the swap-device changeable like the root. | |
29 | */ | |
30 | ||
31 | /* | |
32 | * 05.04.94 - Multi-page memory management added for v1.1. | |
33 | * Idea by Alex Bligh (alex@cconcepts.co.uk) | |
34 | * | |
35 | * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG | |
36 | * (Gerhard.Wichert@pdb.siemens.de) | |
37 | * | |
38 | * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) | |
39 | */ | |
40 | ||
41 | #include <linux/kernel_stat.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/hugetlb.h> | |
44 | #include <linux/mman.h> | |
45 | #include <linux/swap.h> | |
46 | #include <linux/highmem.h> | |
47 | #include <linux/pagemap.h> | |
9a840895 | 48 | #include <linux/ksm.h> |
1da177e4 | 49 | #include <linux/rmap.h> |
b95f1b31 | 50 | #include <linux/export.h> |
0ff92245 | 51 | #include <linux/delayacct.h> |
1da177e4 | 52 | #include <linux/init.h> |
01c8f1c4 | 53 | #include <linux/pfn_t.h> |
edc79b2a | 54 | #include <linux/writeback.h> |
8a9f3ccd | 55 | #include <linux/memcontrol.h> |
cddb8a5c | 56 | #include <linux/mmu_notifier.h> |
3dc14741 HD |
57 | #include <linux/kallsyms.h> |
58 | #include <linux/swapops.h> | |
59 | #include <linux/elf.h> | |
5a0e3ad6 | 60 | #include <linux/gfp.h> |
4daae3b4 | 61 | #include <linux/migrate.h> |
2fbc57c5 | 62 | #include <linux/string.h> |
0abdd7a8 | 63 | #include <linux/dma-debug.h> |
1592eef0 | 64 | #include <linux/debugfs.h> |
6b251fc9 | 65 | #include <linux/userfaultfd_k.h> |
bc2466e4 | 66 | #include <linux/dax.h> |
1da177e4 | 67 | |
6952b61d | 68 | #include <asm/io.h> |
33a709b2 | 69 | #include <asm/mmu_context.h> |
1da177e4 LT |
70 | #include <asm/pgalloc.h> |
71 | #include <asm/uaccess.h> | |
72 | #include <asm/tlb.h> | |
73 | #include <asm/tlbflush.h> | |
74 | #include <asm/pgtable.h> | |
75 | ||
42b77728 JB |
76 | #include "internal.h" |
77 | ||
90572890 PZ |
78 | #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS |
79 | #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid. | |
75980e97 PZ |
80 | #endif |
81 | ||
d41dee36 | 82 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
83 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
84 | unsigned long max_mapnr; | |
85 | struct page *mem_map; | |
86 | ||
87 | EXPORT_SYMBOL(max_mapnr); | |
88 | EXPORT_SYMBOL(mem_map); | |
89 | #endif | |
90 | ||
1da177e4 LT |
91 | /* |
92 | * A number of key systems in x86 including ioremap() rely on the assumption | |
93 | * that high_memory defines the upper bound on direct map memory, then end | |
94 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and | |
95 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL | |
96 | * and ZONE_HIGHMEM. | |
97 | */ | |
98 | void * high_memory; | |
1da177e4 | 99 | |
1da177e4 | 100 | EXPORT_SYMBOL(high_memory); |
1da177e4 | 101 | |
32a93233 IM |
102 | /* |
103 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
104 | * | |
105 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
106 | * as ancient (libc5 based) binaries can segfault. ) | |
107 | */ | |
108 | int randomize_va_space __read_mostly = | |
109 | #ifdef CONFIG_COMPAT_BRK | |
110 | 1; | |
111 | #else | |
112 | 2; | |
113 | #endif | |
a62eaf15 AK |
114 | |
115 | static int __init disable_randmaps(char *s) | |
116 | { | |
117 | randomize_va_space = 0; | |
9b41046c | 118 | return 1; |
a62eaf15 AK |
119 | } |
120 | __setup("norandmaps", disable_randmaps); | |
121 | ||
62eede62 | 122 | unsigned long zero_pfn __read_mostly; |
03f6462a | 123 | unsigned long highest_memmap_pfn __read_mostly; |
a13ea5b7 | 124 | |
0b70068e AB |
125 | EXPORT_SYMBOL(zero_pfn); |
126 | ||
a13ea5b7 HD |
127 | /* |
128 | * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init() | |
129 | */ | |
130 | static int __init init_zero_pfn(void) | |
131 | { | |
132 | zero_pfn = page_to_pfn(ZERO_PAGE(0)); | |
133 | return 0; | |
134 | } | |
135 | core_initcall(init_zero_pfn); | |
a62eaf15 | 136 | |
d559db08 | 137 | |
34e55232 KH |
138 | #if defined(SPLIT_RSS_COUNTING) |
139 | ||
ea48cf78 | 140 | void sync_mm_rss(struct mm_struct *mm) |
34e55232 KH |
141 | { |
142 | int i; | |
143 | ||
144 | for (i = 0; i < NR_MM_COUNTERS; i++) { | |
05af2e10 DR |
145 | if (current->rss_stat.count[i]) { |
146 | add_mm_counter(mm, i, current->rss_stat.count[i]); | |
147 | current->rss_stat.count[i] = 0; | |
34e55232 KH |
148 | } |
149 | } | |
05af2e10 | 150 | current->rss_stat.events = 0; |
34e55232 KH |
151 | } |
152 | ||
153 | static void add_mm_counter_fast(struct mm_struct *mm, int member, int val) | |
154 | { | |
155 | struct task_struct *task = current; | |
156 | ||
157 | if (likely(task->mm == mm)) | |
158 | task->rss_stat.count[member] += val; | |
159 | else | |
160 | add_mm_counter(mm, member, val); | |
161 | } | |
162 | #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1) | |
163 | #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1) | |
164 | ||
165 | /* sync counter once per 64 page faults */ | |
166 | #define TASK_RSS_EVENTS_THRESH (64) | |
167 | static void check_sync_rss_stat(struct task_struct *task) | |
168 | { | |
169 | if (unlikely(task != current)) | |
170 | return; | |
171 | if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH)) | |
ea48cf78 | 172 | sync_mm_rss(task->mm); |
34e55232 | 173 | } |
9547d01b | 174 | #else /* SPLIT_RSS_COUNTING */ |
34e55232 KH |
175 | |
176 | #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member) | |
177 | #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member) | |
178 | ||
179 | static void check_sync_rss_stat(struct task_struct *task) | |
180 | { | |
181 | } | |
182 | ||
9547d01b PZ |
183 | #endif /* SPLIT_RSS_COUNTING */ |
184 | ||
185 | #ifdef HAVE_GENERIC_MMU_GATHER | |
186 | ||
ca1d6c7d | 187 | static bool tlb_next_batch(struct mmu_gather *tlb) |
9547d01b PZ |
188 | { |
189 | struct mmu_gather_batch *batch; | |
190 | ||
191 | batch = tlb->active; | |
192 | if (batch->next) { | |
193 | tlb->active = batch->next; | |
ca1d6c7d | 194 | return true; |
9547d01b PZ |
195 | } |
196 | ||
53a59fc6 | 197 | if (tlb->batch_count == MAX_GATHER_BATCH_COUNT) |
ca1d6c7d | 198 | return false; |
53a59fc6 | 199 | |
9547d01b PZ |
200 | batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0); |
201 | if (!batch) | |
ca1d6c7d | 202 | return false; |
9547d01b | 203 | |
53a59fc6 | 204 | tlb->batch_count++; |
9547d01b PZ |
205 | batch->next = NULL; |
206 | batch->nr = 0; | |
207 | batch->max = MAX_GATHER_BATCH; | |
208 | ||
209 | tlb->active->next = batch; | |
210 | tlb->active = batch; | |
211 | ||
ca1d6c7d | 212 | return true; |
9547d01b PZ |
213 | } |
214 | ||
215 | /* tlb_gather_mmu | |
216 | * Called to initialize an (on-stack) mmu_gather structure for page-table | |
217 | * tear-down from @mm. The @fullmm argument is used when @mm is without | |
218 | * users and we're going to destroy the full address space (exit/execve). | |
219 | */ | |
2b047252 | 220 | void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end) |
9547d01b PZ |
221 | { |
222 | tlb->mm = mm; | |
223 | ||
2b047252 LT |
224 | /* Is it from 0 to ~0? */ |
225 | tlb->fullmm = !(start | (end+1)); | |
1de14c3c | 226 | tlb->need_flush_all = 0; |
9547d01b PZ |
227 | tlb->local.next = NULL; |
228 | tlb->local.nr = 0; | |
229 | tlb->local.max = ARRAY_SIZE(tlb->__pages); | |
230 | tlb->active = &tlb->local; | |
53a59fc6 | 231 | tlb->batch_count = 0; |
9547d01b PZ |
232 | |
233 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE | |
234 | tlb->batch = NULL; | |
235 | #endif | |
e77b0852 | 236 | tlb->page_size = 0; |
fb7332a9 WD |
237 | |
238 | __tlb_reset_range(tlb); | |
9547d01b PZ |
239 | } |
240 | ||
1cf35d47 | 241 | static void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) |
9547d01b | 242 | { |
721c21c1 WD |
243 | if (!tlb->end) |
244 | return; | |
245 | ||
9547d01b | 246 | tlb_flush(tlb); |
34ee645e | 247 | mmu_notifier_invalidate_range(tlb->mm, tlb->start, tlb->end); |
9547d01b PZ |
248 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE |
249 | tlb_table_flush(tlb); | |
34e55232 | 250 | #endif |
fb7332a9 | 251 | __tlb_reset_range(tlb); |
1cf35d47 LT |
252 | } |
253 | ||
254 | static void tlb_flush_mmu_free(struct mmu_gather *tlb) | |
255 | { | |
256 | struct mmu_gather_batch *batch; | |
34e55232 | 257 | |
721c21c1 | 258 | for (batch = &tlb->local; batch && batch->nr; batch = batch->next) { |
9547d01b PZ |
259 | free_pages_and_swap_cache(batch->pages, batch->nr); |
260 | batch->nr = 0; | |
261 | } | |
262 | tlb->active = &tlb->local; | |
263 | } | |
264 | ||
1cf35d47 LT |
265 | void tlb_flush_mmu(struct mmu_gather *tlb) |
266 | { | |
1cf35d47 LT |
267 | tlb_flush_mmu_tlbonly(tlb); |
268 | tlb_flush_mmu_free(tlb); | |
269 | } | |
270 | ||
9547d01b PZ |
271 | /* tlb_finish_mmu |
272 | * Called at the end of the shootdown operation to free up any resources | |
273 | * that were required. | |
274 | */ | |
275 | void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) | |
276 | { | |
277 | struct mmu_gather_batch *batch, *next; | |
278 | ||
279 | tlb_flush_mmu(tlb); | |
280 | ||
281 | /* keep the page table cache within bounds */ | |
282 | check_pgt_cache(); | |
283 | ||
284 | for (batch = tlb->local.next; batch; batch = next) { | |
285 | next = batch->next; | |
286 | free_pages((unsigned long)batch, 0); | |
287 | } | |
288 | tlb->local.next = NULL; | |
289 | } | |
290 | ||
291 | /* __tlb_remove_page | |
292 | * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while | |
293 | * handling the additional races in SMP caused by other CPUs caching valid | |
294 | * mappings in their TLBs. Returns the number of free page slots left. | |
295 | * When out of page slots we must call tlb_flush_mmu(). | |
e9d55e15 | 296 | *returns true if the caller should flush. |
9547d01b | 297 | */ |
e77b0852 | 298 | bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_size) |
9547d01b PZ |
299 | { |
300 | struct mmu_gather_batch *batch; | |
301 | ||
fb7332a9 | 302 | VM_BUG_ON(!tlb->end); |
9547d01b | 303 | |
e77b0852 AK |
304 | if (!tlb->page_size) |
305 | tlb->page_size = page_size; | |
306 | else { | |
307 | if (page_size != tlb->page_size) | |
308 | return true; | |
309 | } | |
310 | ||
9547d01b | 311 | batch = tlb->active; |
9547d01b PZ |
312 | if (batch->nr == batch->max) { |
313 | if (!tlb_next_batch(tlb)) | |
e9d55e15 | 314 | return true; |
0b43c3aa | 315 | batch = tlb->active; |
9547d01b | 316 | } |
309381fe | 317 | VM_BUG_ON_PAGE(batch->nr > batch->max, page); |
9547d01b | 318 | |
e9d55e15 AK |
319 | batch->pages[batch->nr++] = page; |
320 | return false; | |
9547d01b PZ |
321 | } |
322 | ||
323 | #endif /* HAVE_GENERIC_MMU_GATHER */ | |
324 | ||
26723911 PZ |
325 | #ifdef CONFIG_HAVE_RCU_TABLE_FREE |
326 | ||
327 | /* | |
328 | * See the comment near struct mmu_table_batch. | |
329 | */ | |
330 | ||
331 | static void tlb_remove_table_smp_sync(void *arg) | |
332 | { | |
333 | /* Simply deliver the interrupt */ | |
334 | } | |
335 | ||
336 | static void tlb_remove_table_one(void *table) | |
337 | { | |
338 | /* | |
339 | * This isn't an RCU grace period and hence the page-tables cannot be | |
340 | * assumed to be actually RCU-freed. | |
341 | * | |
342 | * It is however sufficient for software page-table walkers that rely on | |
343 | * IRQ disabling. See the comment near struct mmu_table_batch. | |
344 | */ | |
345 | smp_call_function(tlb_remove_table_smp_sync, NULL, 1); | |
346 | __tlb_remove_table(table); | |
347 | } | |
348 | ||
349 | static void tlb_remove_table_rcu(struct rcu_head *head) | |
350 | { | |
351 | struct mmu_table_batch *batch; | |
352 | int i; | |
353 | ||
354 | batch = container_of(head, struct mmu_table_batch, rcu); | |
355 | ||
356 | for (i = 0; i < batch->nr; i++) | |
357 | __tlb_remove_table(batch->tables[i]); | |
358 | ||
359 | free_page((unsigned long)batch); | |
360 | } | |
361 | ||
362 | void tlb_table_flush(struct mmu_gather *tlb) | |
363 | { | |
364 | struct mmu_table_batch **batch = &tlb->batch; | |
365 | ||
366 | if (*batch) { | |
367 | call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); | |
368 | *batch = NULL; | |
369 | } | |
370 | } | |
371 | ||
372 | void tlb_remove_table(struct mmu_gather *tlb, void *table) | |
373 | { | |
374 | struct mmu_table_batch **batch = &tlb->batch; | |
375 | ||
26723911 PZ |
376 | /* |
377 | * When there's less then two users of this mm there cannot be a | |
378 | * concurrent page-table walk. | |
379 | */ | |
380 | if (atomic_read(&tlb->mm->mm_users) < 2) { | |
381 | __tlb_remove_table(table); | |
382 | return; | |
383 | } | |
384 | ||
385 | if (*batch == NULL) { | |
386 | *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); | |
387 | if (*batch == NULL) { | |
388 | tlb_remove_table_one(table); | |
389 | return; | |
390 | } | |
391 | (*batch)->nr = 0; | |
392 | } | |
393 | (*batch)->tables[(*batch)->nr++] = table; | |
394 | if ((*batch)->nr == MAX_TABLE_BATCH) | |
395 | tlb_table_flush(tlb); | |
396 | } | |
397 | ||
9547d01b | 398 | #endif /* CONFIG_HAVE_RCU_TABLE_FREE */ |
26723911 | 399 | |
1da177e4 LT |
400 | /* |
401 | * Note: this doesn't free the actual pages themselves. That | |
402 | * has been handled earlier when unmapping all the memory regions. | |
403 | */ | |
9e1b32ca BH |
404 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, |
405 | unsigned long addr) | |
1da177e4 | 406 | { |
2f569afd | 407 | pgtable_t token = pmd_pgtable(*pmd); |
e0da382c | 408 | pmd_clear(pmd); |
9e1b32ca | 409 | pte_free_tlb(tlb, token, addr); |
e1f56c89 | 410 | atomic_long_dec(&tlb->mm->nr_ptes); |
1da177e4 LT |
411 | } |
412 | ||
e0da382c HD |
413 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
414 | unsigned long addr, unsigned long end, | |
415 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
416 | { |
417 | pmd_t *pmd; | |
418 | unsigned long next; | |
e0da382c | 419 | unsigned long start; |
1da177e4 | 420 | |
e0da382c | 421 | start = addr; |
1da177e4 | 422 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
423 | do { |
424 | next = pmd_addr_end(addr, end); | |
425 | if (pmd_none_or_clear_bad(pmd)) | |
426 | continue; | |
9e1b32ca | 427 | free_pte_range(tlb, pmd, addr); |
1da177e4 LT |
428 | } while (pmd++, addr = next, addr != end); |
429 | ||
e0da382c HD |
430 | start &= PUD_MASK; |
431 | if (start < floor) | |
432 | return; | |
433 | if (ceiling) { | |
434 | ceiling &= PUD_MASK; | |
435 | if (!ceiling) | |
436 | return; | |
1da177e4 | 437 | } |
e0da382c HD |
438 | if (end - 1 > ceiling - 1) |
439 | return; | |
440 | ||
441 | pmd = pmd_offset(pud, start); | |
442 | pud_clear(pud); | |
9e1b32ca | 443 | pmd_free_tlb(tlb, pmd, start); |
dc6c9a35 | 444 | mm_dec_nr_pmds(tlb->mm); |
1da177e4 LT |
445 | } |
446 | ||
e0da382c HD |
447 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
448 | unsigned long addr, unsigned long end, | |
449 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
450 | { |
451 | pud_t *pud; | |
452 | unsigned long next; | |
e0da382c | 453 | unsigned long start; |
1da177e4 | 454 | |
e0da382c | 455 | start = addr; |
1da177e4 | 456 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
457 | do { |
458 | next = pud_addr_end(addr, end); | |
459 | if (pud_none_or_clear_bad(pud)) | |
460 | continue; | |
e0da382c | 461 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
462 | } while (pud++, addr = next, addr != end); |
463 | ||
e0da382c HD |
464 | start &= PGDIR_MASK; |
465 | if (start < floor) | |
466 | return; | |
467 | if (ceiling) { | |
468 | ceiling &= PGDIR_MASK; | |
469 | if (!ceiling) | |
470 | return; | |
1da177e4 | 471 | } |
e0da382c HD |
472 | if (end - 1 > ceiling - 1) |
473 | return; | |
474 | ||
475 | pud = pud_offset(pgd, start); | |
476 | pgd_clear(pgd); | |
9e1b32ca | 477 | pud_free_tlb(tlb, pud, start); |
1da177e4 LT |
478 | } |
479 | ||
480 | /* | |
e0da382c | 481 | * This function frees user-level page tables of a process. |
1da177e4 | 482 | */ |
42b77728 | 483 | void free_pgd_range(struct mmu_gather *tlb, |
e0da382c HD |
484 | unsigned long addr, unsigned long end, |
485 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
486 | { |
487 | pgd_t *pgd; | |
488 | unsigned long next; | |
e0da382c HD |
489 | |
490 | /* | |
491 | * The next few lines have given us lots of grief... | |
492 | * | |
493 | * Why are we testing PMD* at this top level? Because often | |
494 | * there will be no work to do at all, and we'd prefer not to | |
495 | * go all the way down to the bottom just to discover that. | |
496 | * | |
497 | * Why all these "- 1"s? Because 0 represents both the bottom | |
498 | * of the address space and the top of it (using -1 for the | |
499 | * top wouldn't help much: the masks would do the wrong thing). | |
500 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
501 | * the address space, but end 0 and ceiling 0 refer to the top | |
502 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
503 | * that end 0 case should be mythical). | |
504 | * | |
505 | * Wherever addr is brought up or ceiling brought down, we must | |
506 | * be careful to reject "the opposite 0" before it confuses the | |
507 | * subsequent tests. But what about where end is brought down | |
508 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
509 | * | |
510 | * Whereas we round start (addr) and ceiling down, by different | |
511 | * masks at different levels, in order to test whether a table | |
512 | * now has no other vmas using it, so can be freed, we don't | |
513 | * bother to round floor or end up - the tests don't need that. | |
514 | */ | |
1da177e4 | 515 | |
e0da382c HD |
516 | addr &= PMD_MASK; |
517 | if (addr < floor) { | |
518 | addr += PMD_SIZE; | |
519 | if (!addr) | |
520 | return; | |
521 | } | |
522 | if (ceiling) { | |
523 | ceiling &= PMD_MASK; | |
524 | if (!ceiling) | |
525 | return; | |
526 | } | |
527 | if (end - 1 > ceiling - 1) | |
528 | end -= PMD_SIZE; | |
529 | if (addr > end - 1) | |
530 | return; | |
531 | ||
42b77728 | 532 | pgd = pgd_offset(tlb->mm, addr); |
1da177e4 LT |
533 | do { |
534 | next = pgd_addr_end(addr, end); | |
535 | if (pgd_none_or_clear_bad(pgd)) | |
536 | continue; | |
42b77728 | 537 | free_pud_range(tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 538 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
539 | } |
540 | ||
42b77728 | 541 | void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3bf5ee95 | 542 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
543 | { |
544 | while (vma) { | |
545 | struct vm_area_struct *next = vma->vm_next; | |
546 | unsigned long addr = vma->vm_start; | |
547 | ||
8f4f8c16 | 548 | /* |
25d9e2d1 | 549 | * Hide vma from rmap and truncate_pagecache before freeing |
550 | * pgtables | |
8f4f8c16 | 551 | */ |
5beb4930 | 552 | unlink_anon_vmas(vma); |
8f4f8c16 HD |
553 | unlink_file_vma(vma); |
554 | ||
9da61aef | 555 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 556 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 557 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
558 | } else { |
559 | /* | |
560 | * Optimization: gather nearby vmas into one call down | |
561 | */ | |
562 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 563 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
564 | vma = next; |
565 | next = vma->vm_next; | |
5beb4930 | 566 | unlink_anon_vmas(vma); |
8f4f8c16 | 567 | unlink_file_vma(vma); |
3bf5ee95 HD |
568 | } |
569 | free_pgd_range(tlb, addr, vma->vm_end, | |
570 | floor, next? next->vm_start: ceiling); | |
571 | } | |
e0da382c HD |
572 | vma = next; |
573 | } | |
1da177e4 LT |
574 | } |
575 | ||
3ed3a4f0 | 576 | int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
1da177e4 | 577 | { |
c4088ebd | 578 | spinlock_t *ptl; |
2f569afd | 579 | pgtable_t new = pte_alloc_one(mm, address); |
1bb3630e HD |
580 | if (!new) |
581 | return -ENOMEM; | |
582 | ||
362a61ad NP |
583 | /* |
584 | * Ensure all pte setup (eg. pte page lock and page clearing) are | |
585 | * visible before the pte is made visible to other CPUs by being | |
586 | * put into page tables. | |
587 | * | |
588 | * The other side of the story is the pointer chasing in the page | |
589 | * table walking code (when walking the page table without locking; | |
590 | * ie. most of the time). Fortunately, these data accesses consist | |
591 | * of a chain of data-dependent loads, meaning most CPUs (alpha | |
592 | * being the notable exception) will already guarantee loads are | |
593 | * seen in-order. See the alpha page table accessors for the | |
594 | * smp_read_barrier_depends() barriers in page table walking code. | |
595 | */ | |
596 | smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ | |
597 | ||
c4088ebd | 598 | ptl = pmd_lock(mm, pmd); |
8ac1f832 | 599 | if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ |
e1f56c89 | 600 | atomic_long_inc(&mm->nr_ptes); |
1da177e4 | 601 | pmd_populate(mm, pmd, new); |
2f569afd | 602 | new = NULL; |
4b471e88 | 603 | } |
c4088ebd | 604 | spin_unlock(ptl); |
2f569afd MS |
605 | if (new) |
606 | pte_free(mm, new); | |
1bb3630e | 607 | return 0; |
1da177e4 LT |
608 | } |
609 | ||
1bb3630e | 610 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 611 | { |
1bb3630e HD |
612 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
613 | if (!new) | |
614 | return -ENOMEM; | |
615 | ||
362a61ad NP |
616 | smp_wmb(); /* See comment in __pte_alloc */ |
617 | ||
1bb3630e | 618 | spin_lock(&init_mm.page_table_lock); |
8ac1f832 | 619 | if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ |
1bb3630e | 620 | pmd_populate_kernel(&init_mm, pmd, new); |
2f569afd | 621 | new = NULL; |
4b471e88 | 622 | } |
1bb3630e | 623 | spin_unlock(&init_mm.page_table_lock); |
2f569afd MS |
624 | if (new) |
625 | pte_free_kernel(&init_mm, new); | |
1bb3630e | 626 | return 0; |
1da177e4 LT |
627 | } |
628 | ||
d559db08 KH |
629 | static inline void init_rss_vec(int *rss) |
630 | { | |
631 | memset(rss, 0, sizeof(int) * NR_MM_COUNTERS); | |
632 | } | |
633 | ||
634 | static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss) | |
ae859762 | 635 | { |
d559db08 KH |
636 | int i; |
637 | ||
34e55232 | 638 | if (current->mm == mm) |
05af2e10 | 639 | sync_mm_rss(mm); |
d559db08 KH |
640 | for (i = 0; i < NR_MM_COUNTERS; i++) |
641 | if (rss[i]) | |
642 | add_mm_counter(mm, i, rss[i]); | |
ae859762 HD |
643 | } |
644 | ||
b5810039 | 645 | /* |
6aab341e LT |
646 | * This function is called to print an error when a bad pte |
647 | * is found. For example, we might have a PFN-mapped pte in | |
648 | * a region that doesn't allow it. | |
b5810039 NP |
649 | * |
650 | * The calling function must still handle the error. | |
651 | */ | |
3dc14741 HD |
652 | static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, |
653 | pte_t pte, struct page *page) | |
b5810039 | 654 | { |
3dc14741 HD |
655 | pgd_t *pgd = pgd_offset(vma->vm_mm, addr); |
656 | pud_t *pud = pud_offset(pgd, addr); | |
657 | pmd_t *pmd = pmd_offset(pud, addr); | |
658 | struct address_space *mapping; | |
659 | pgoff_t index; | |
d936cf9b HD |
660 | static unsigned long resume; |
661 | static unsigned long nr_shown; | |
662 | static unsigned long nr_unshown; | |
663 | ||
664 | /* | |
665 | * Allow a burst of 60 reports, then keep quiet for that minute; | |
666 | * or allow a steady drip of one report per second. | |
667 | */ | |
668 | if (nr_shown == 60) { | |
669 | if (time_before(jiffies, resume)) { | |
670 | nr_unshown++; | |
671 | return; | |
672 | } | |
673 | if (nr_unshown) { | |
1170532b JP |
674 | pr_alert("BUG: Bad page map: %lu messages suppressed\n", |
675 | nr_unshown); | |
d936cf9b HD |
676 | nr_unshown = 0; |
677 | } | |
678 | nr_shown = 0; | |
679 | } | |
680 | if (nr_shown++ == 0) | |
681 | resume = jiffies + 60 * HZ; | |
3dc14741 HD |
682 | |
683 | mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; | |
684 | index = linear_page_index(vma, addr); | |
685 | ||
1170532b JP |
686 | pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", |
687 | current->comm, | |
688 | (long long)pte_val(pte), (long long)pmd_val(*pmd)); | |
718a3821 | 689 | if (page) |
f0b791a3 | 690 | dump_page(page, "bad pte"); |
1170532b JP |
691 | pr_alert("addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", |
692 | (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); | |
3dc14741 HD |
693 | /* |
694 | * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y | |
695 | */ | |
2682582a KK |
696 | pr_alert("file:%pD fault:%pf mmap:%pf readpage:%pf\n", |
697 | vma->vm_file, | |
698 | vma->vm_ops ? vma->vm_ops->fault : NULL, | |
699 | vma->vm_file ? vma->vm_file->f_op->mmap : NULL, | |
700 | mapping ? mapping->a_ops->readpage : NULL); | |
b5810039 | 701 | dump_stack(); |
373d4d09 | 702 | add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
b5810039 NP |
703 | } |
704 | ||
ee498ed7 | 705 | /* |
7e675137 | 706 | * vm_normal_page -- This function gets the "struct page" associated with a pte. |
6aab341e | 707 | * |
7e675137 NP |
708 | * "Special" mappings do not wish to be associated with a "struct page" (either |
709 | * it doesn't exist, or it exists but they don't want to touch it). In this | |
710 | * case, NULL is returned here. "Normal" mappings do have a struct page. | |
b379d790 | 711 | * |
7e675137 NP |
712 | * There are 2 broad cases. Firstly, an architecture may define a pte_special() |
713 | * pte bit, in which case this function is trivial. Secondly, an architecture | |
714 | * may not have a spare pte bit, which requires a more complicated scheme, | |
715 | * described below. | |
716 | * | |
717 | * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a | |
718 | * special mapping (even if there are underlying and valid "struct pages"). | |
719 | * COWed pages of a VM_PFNMAP are always normal. | |
6aab341e | 720 | * |
b379d790 JH |
721 | * The way we recognize COWed pages within VM_PFNMAP mappings is through the |
722 | * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit | |
7e675137 NP |
723 | * set, and the vm_pgoff will point to the first PFN mapped: thus every special |
724 | * mapping will always honor the rule | |
6aab341e LT |
725 | * |
726 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
727 | * | |
7e675137 NP |
728 | * And for normal mappings this is false. |
729 | * | |
730 | * This restricts such mappings to be a linear translation from virtual address | |
731 | * to pfn. To get around this restriction, we allow arbitrary mappings so long | |
732 | * as the vma is not a COW mapping; in that case, we know that all ptes are | |
733 | * special (because none can have been COWed). | |
b379d790 | 734 | * |
b379d790 | 735 | * |
7e675137 | 736 | * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. |
b379d790 JH |
737 | * |
738 | * VM_MIXEDMAP mappings can likewise contain memory with or without "struct | |
739 | * page" backing, however the difference is that _all_ pages with a struct | |
740 | * page (that is, those where pfn_valid is true) are refcounted and considered | |
741 | * normal pages by the VM. The disadvantage is that pages are refcounted | |
742 | * (which can be slower and simply not an option for some PFNMAP users). The | |
743 | * advantage is that we don't have to follow the strict linearity rule of | |
744 | * PFNMAP mappings in order to support COWable mappings. | |
745 | * | |
ee498ed7 | 746 | */ |
7e675137 NP |
747 | #ifdef __HAVE_ARCH_PTE_SPECIAL |
748 | # define HAVE_PTE_SPECIAL 1 | |
749 | #else | |
750 | # define HAVE_PTE_SPECIAL 0 | |
751 | #endif | |
752 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, | |
753 | pte_t pte) | |
ee498ed7 | 754 | { |
22b31eec | 755 | unsigned long pfn = pte_pfn(pte); |
7e675137 NP |
756 | |
757 | if (HAVE_PTE_SPECIAL) { | |
b38af472 | 758 | if (likely(!pte_special(pte))) |
22b31eec | 759 | goto check_pfn; |
667a0a06 DV |
760 | if (vma->vm_ops && vma->vm_ops->find_special_page) |
761 | return vma->vm_ops->find_special_page(vma, addr); | |
a13ea5b7 HD |
762 | if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)) |
763 | return NULL; | |
62eede62 | 764 | if (!is_zero_pfn(pfn)) |
22b31eec | 765 | print_bad_pte(vma, addr, pte, NULL); |
7e675137 NP |
766 | return NULL; |
767 | } | |
768 | ||
769 | /* !HAVE_PTE_SPECIAL case follows: */ | |
770 | ||
b379d790 JH |
771 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { |
772 | if (vma->vm_flags & VM_MIXEDMAP) { | |
773 | if (!pfn_valid(pfn)) | |
774 | return NULL; | |
775 | goto out; | |
776 | } else { | |
7e675137 NP |
777 | unsigned long off; |
778 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
b379d790 JH |
779 | if (pfn == vma->vm_pgoff + off) |
780 | return NULL; | |
781 | if (!is_cow_mapping(vma->vm_flags)) | |
782 | return NULL; | |
783 | } | |
6aab341e LT |
784 | } |
785 | ||
b38af472 HD |
786 | if (is_zero_pfn(pfn)) |
787 | return NULL; | |
22b31eec HD |
788 | check_pfn: |
789 | if (unlikely(pfn > highest_memmap_pfn)) { | |
790 | print_bad_pte(vma, addr, pte, NULL); | |
791 | return NULL; | |
792 | } | |
6aab341e LT |
793 | |
794 | /* | |
7e675137 | 795 | * NOTE! We still have PageReserved() pages in the page tables. |
7e675137 | 796 | * eg. VDSO mappings can cause them to exist. |
6aab341e | 797 | */ |
b379d790 | 798 | out: |
6aab341e | 799 | return pfn_to_page(pfn); |
ee498ed7 HD |
800 | } |
801 | ||
28093f9f GS |
802 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
803 | struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr, | |
804 | pmd_t pmd) | |
805 | { | |
806 | unsigned long pfn = pmd_pfn(pmd); | |
807 | ||
808 | /* | |
809 | * There is no pmd_special() but there may be special pmds, e.g. | |
810 | * in a direct-access (dax) mapping, so let's just replicate the | |
811 | * !HAVE_PTE_SPECIAL case from vm_normal_page() here. | |
812 | */ | |
813 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { | |
814 | if (vma->vm_flags & VM_MIXEDMAP) { | |
815 | if (!pfn_valid(pfn)) | |
816 | return NULL; | |
817 | goto out; | |
818 | } else { | |
819 | unsigned long off; | |
820 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
821 | if (pfn == vma->vm_pgoff + off) | |
822 | return NULL; | |
823 | if (!is_cow_mapping(vma->vm_flags)) | |
824 | return NULL; | |
825 | } | |
826 | } | |
827 | ||
828 | if (is_zero_pfn(pfn)) | |
829 | return NULL; | |
830 | if (unlikely(pfn > highest_memmap_pfn)) | |
831 | return NULL; | |
832 | ||
833 | /* | |
834 | * NOTE! We still have PageReserved() pages in the page tables. | |
835 | * eg. VDSO mappings can cause them to exist. | |
836 | */ | |
837 | out: | |
838 | return pfn_to_page(pfn); | |
839 | } | |
840 | #endif | |
841 | ||
1da177e4 LT |
842 | /* |
843 | * copy one vm_area from one task to the other. Assumes the page tables | |
844 | * already present in the new task to be cleared in the whole range | |
845 | * covered by this vma. | |
1da177e4 LT |
846 | */ |
847 | ||
570a335b | 848 | static inline unsigned long |
1da177e4 | 849 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 850 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 851 | unsigned long addr, int *rss) |
1da177e4 | 852 | { |
b5810039 | 853 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
854 | pte_t pte = *src_pte; |
855 | struct page *page; | |
1da177e4 LT |
856 | |
857 | /* pte contains position in swap or file, so copy. */ | |
858 | if (unlikely(!pte_present(pte))) { | |
0661a336 KS |
859 | swp_entry_t entry = pte_to_swp_entry(pte); |
860 | ||
861 | if (likely(!non_swap_entry(entry))) { | |
862 | if (swap_duplicate(entry) < 0) | |
863 | return entry.val; | |
864 | ||
865 | /* make sure dst_mm is on swapoff's mmlist. */ | |
866 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
867 | spin_lock(&mmlist_lock); | |
868 | if (list_empty(&dst_mm->mmlist)) | |
869 | list_add(&dst_mm->mmlist, | |
870 | &src_mm->mmlist); | |
871 | spin_unlock(&mmlist_lock); | |
872 | } | |
873 | rss[MM_SWAPENTS]++; | |
874 | } else if (is_migration_entry(entry)) { | |
875 | page = migration_entry_to_page(entry); | |
876 | ||
eca56ff9 | 877 | rss[mm_counter(page)]++; |
0661a336 KS |
878 | |
879 | if (is_write_migration_entry(entry) && | |
880 | is_cow_mapping(vm_flags)) { | |
881 | /* | |
882 | * COW mappings require pages in both | |
883 | * parent and child to be set to read. | |
884 | */ | |
885 | make_migration_entry_read(&entry); | |
886 | pte = swp_entry_to_pte(entry); | |
887 | if (pte_swp_soft_dirty(*src_pte)) | |
888 | pte = pte_swp_mksoft_dirty(pte); | |
889 | set_pte_at(src_mm, addr, src_pte, pte); | |
0697212a | 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); | |
53f9263b | 915 | page_dup_rmap(page, false); |
eca56ff9 | 916 | rss[mm_counter(page)]++; |
6aab341e | 917 | } |
ae859762 HD |
918 | |
919 | out_set_pte: | |
920 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
570a335b | 921 | return 0; |
1da177e4 LT |
922 | } |
923 | ||
21bda264 | 924 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
71e3aac0 AA |
925 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, |
926 | unsigned long addr, unsigned long end) | |
1da177e4 | 927 | { |
c36987e2 | 928 | pte_t *orig_src_pte, *orig_dst_pte; |
1da177e4 | 929 | pte_t *src_pte, *dst_pte; |
c74df32c | 930 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 931 | int progress = 0; |
d559db08 | 932 | int rss[NR_MM_COUNTERS]; |
570a335b | 933 | swp_entry_t entry = (swp_entry_t){0}; |
1da177e4 LT |
934 | |
935 | again: | |
d559db08 KH |
936 | init_rss_vec(rss); |
937 | ||
c74df32c | 938 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
939 | if (!dst_pte) |
940 | return -ENOMEM; | |
ece0e2b6 | 941 | src_pte = pte_offset_map(src_pmd, addr); |
4c21e2f2 | 942 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 943 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
c36987e2 DN |
944 | orig_src_pte = src_pte; |
945 | orig_dst_pte = dst_pte; | |
6606c3e0 | 946 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 947 | |
1da177e4 LT |
948 | do { |
949 | /* | |
950 | * We are holding two locks at this point - either of them | |
951 | * could generate latencies in another task on another CPU. | |
952 | */ | |
e040f218 HD |
953 | if (progress >= 32) { |
954 | progress = 0; | |
955 | if (need_resched() || | |
95c354fe | 956 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
957 | break; |
958 | } | |
1da177e4 LT |
959 | if (pte_none(*src_pte)) { |
960 | progress++; | |
961 | continue; | |
962 | } | |
570a335b HD |
963 | entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, |
964 | vma, addr, rss); | |
965 | if (entry.val) | |
966 | break; | |
1da177e4 LT |
967 | progress += 8; |
968 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 969 | |
6606c3e0 | 970 | arch_leave_lazy_mmu_mode(); |
c74df32c | 971 | spin_unlock(src_ptl); |
ece0e2b6 | 972 | pte_unmap(orig_src_pte); |
d559db08 | 973 | add_mm_rss_vec(dst_mm, rss); |
c36987e2 | 974 | pte_unmap_unlock(orig_dst_pte, dst_ptl); |
c74df32c | 975 | cond_resched(); |
570a335b HD |
976 | |
977 | if (entry.val) { | |
978 | if (add_swap_count_continuation(entry, GFP_KERNEL) < 0) | |
979 | return -ENOMEM; | |
980 | progress = 0; | |
981 | } | |
1da177e4 LT |
982 | if (addr != end) |
983 | goto again; | |
984 | return 0; | |
985 | } | |
986 | ||
987 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
988 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
989 | unsigned long addr, unsigned long end) | |
990 | { | |
991 | pmd_t *src_pmd, *dst_pmd; | |
992 | unsigned long next; | |
993 | ||
994 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
995 | if (!dst_pmd) | |
996 | return -ENOMEM; | |
997 | src_pmd = pmd_offset(src_pud, addr); | |
998 | do { | |
999 | next = pmd_addr_end(addr, end); | |
5c7fb56e | 1000 | if (pmd_trans_huge(*src_pmd) || pmd_devmap(*src_pmd)) { |
71e3aac0 | 1001 | int err; |
14d1a55c | 1002 | VM_BUG_ON(next-addr != HPAGE_PMD_SIZE); |
71e3aac0 AA |
1003 | err = copy_huge_pmd(dst_mm, src_mm, |
1004 | dst_pmd, src_pmd, addr, vma); | |
1005 | if (err == -ENOMEM) | |
1006 | return -ENOMEM; | |
1007 | if (!err) | |
1008 | continue; | |
1009 | /* fall through */ | |
1010 | } | |
1da177e4 LT |
1011 | if (pmd_none_or_clear_bad(src_pmd)) |
1012 | continue; | |
1013 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
1014 | vma, addr, next)) | |
1015 | return -ENOMEM; | |
1016 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
1017 | return 0; | |
1018 | } | |
1019 | ||
1020 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1021 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
1022 | unsigned long addr, unsigned long end) | |
1023 | { | |
1024 | pud_t *src_pud, *dst_pud; | |
1025 | unsigned long next; | |
1026 | ||
1027 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
1028 | if (!dst_pud) | |
1029 | return -ENOMEM; | |
1030 | src_pud = pud_offset(src_pgd, addr); | |
1031 | do { | |
1032 | next = pud_addr_end(addr, end); | |
1033 | if (pud_none_or_clear_bad(src_pud)) | |
1034 | continue; | |
1035 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
1036 | vma, addr, next)) | |
1037 | return -ENOMEM; | |
1038 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
1039 | return 0; | |
1040 | } | |
1041 | ||
1042 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
1043 | struct vm_area_struct *vma) | |
1044 | { | |
1045 | pgd_t *src_pgd, *dst_pgd; | |
1046 | unsigned long next; | |
1047 | unsigned long addr = vma->vm_start; | |
1048 | unsigned long end = vma->vm_end; | |
2ec74c3e SG |
1049 | unsigned long mmun_start; /* For mmu_notifiers */ |
1050 | unsigned long mmun_end; /* For mmu_notifiers */ | |
1051 | bool is_cow; | |
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 | */ | |
0661a336 KS |
1060 | if (!(vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) && |
1061 | !vma->anon_vma) | |
1062 | return 0; | |
d992895b | 1063 | |
1da177e4 LT |
1064 | if (is_vm_hugetlb_page(vma)) |
1065 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
1066 | ||
b3b9c293 | 1067 | if (unlikely(vma->vm_flags & VM_PFNMAP)) { |
2ab64037 | 1068 | /* |
1069 | * We do not free on error cases below as remove_vma | |
1070 | * gets called on error from higher level routine | |
1071 | */ | |
5180da41 | 1072 | ret = track_pfn_copy(vma); |
2ab64037 | 1073 | if (ret) |
1074 | return ret; | |
1075 | } | |
1076 | ||
cddb8a5c AA |
1077 | /* |
1078 | * We need to invalidate the secondary MMU mappings only when | |
1079 | * there could be a permission downgrade on the ptes of the | |
1080 | * parent mm. And a permission downgrade will only happen if | |
1081 | * is_cow_mapping() returns true. | |
1082 | */ | |
2ec74c3e SG |
1083 | is_cow = is_cow_mapping(vma->vm_flags); |
1084 | mmun_start = addr; | |
1085 | mmun_end = end; | |
1086 | if (is_cow) | |
1087 | mmu_notifier_invalidate_range_start(src_mm, mmun_start, | |
1088 | mmun_end); | |
cddb8a5c AA |
1089 | |
1090 | ret = 0; | |
1da177e4 LT |
1091 | dst_pgd = pgd_offset(dst_mm, addr); |
1092 | src_pgd = pgd_offset(src_mm, addr); | |
1093 | do { | |
1094 | next = pgd_addr_end(addr, end); | |
1095 | if (pgd_none_or_clear_bad(src_pgd)) | |
1096 | continue; | |
cddb8a5c AA |
1097 | if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
1098 | vma, addr, next))) { | |
1099 | ret = -ENOMEM; | |
1100 | break; | |
1101 | } | |
1da177e4 | 1102 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
cddb8a5c | 1103 | |
2ec74c3e SG |
1104 | if (is_cow) |
1105 | mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end); | |
cddb8a5c | 1106 | return ret; |
1da177e4 LT |
1107 | } |
1108 | ||
51c6f666 | 1109 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 1110 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 1111 | unsigned long addr, unsigned long end, |
97a89413 | 1112 | struct zap_details *details) |
1da177e4 | 1113 | { |
b5810039 | 1114 | struct mm_struct *mm = tlb->mm; |
d16dfc55 | 1115 | int force_flush = 0; |
d559db08 | 1116 | int rss[NR_MM_COUNTERS]; |
97a89413 | 1117 | spinlock_t *ptl; |
5f1a1907 | 1118 | pte_t *start_pte; |
97a89413 | 1119 | pte_t *pte; |
8a5f14a2 | 1120 | swp_entry_t entry; |
e9d55e15 | 1121 | struct page *pending_page = NULL; |
d559db08 | 1122 | |
d16dfc55 | 1123 | again: |
e303297e | 1124 | init_rss_vec(rss); |
5f1a1907 SR |
1125 | start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
1126 | pte = start_pte; | |
6606c3e0 | 1127 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1128 | do { |
1129 | pte_t ptent = *pte; | |
51c6f666 | 1130 | if (pte_none(ptent)) { |
1da177e4 | 1131 | continue; |
51c6f666 | 1132 | } |
6f5e6b9e | 1133 | |
1da177e4 | 1134 | if (pte_present(ptent)) { |
ee498ed7 | 1135 | struct page *page; |
51c6f666 | 1136 | |
6aab341e | 1137 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
1138 | if (unlikely(details) && page) { |
1139 | /* | |
1140 | * unmap_shared_mapping_pages() wants to | |
1141 | * invalidate cache without truncating: | |
1142 | * unmap shared but keep private pages. | |
1143 | */ | |
1144 | if (details->check_mapping && | |
800d8c63 | 1145 | details->check_mapping != page_rmapping(page)) |
1da177e4 | 1146 | continue; |
1da177e4 | 1147 | } |
b5810039 | 1148 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 1149 | tlb->fullmm); |
1da177e4 LT |
1150 | tlb_remove_tlb_entry(tlb, pte, addr); |
1151 | if (unlikely(!page)) | |
1152 | continue; | |
eca56ff9 JM |
1153 | |
1154 | if (!PageAnon(page)) { | |
1cf35d47 | 1155 | if (pte_dirty(ptent)) { |
aac45363 MH |
1156 | /* |
1157 | * oom_reaper cannot tear down dirty | |
1158 | * pages | |
1159 | */ | |
1160 | if (unlikely(details && details->ignore_dirty)) | |
1161 | continue; | |
1cf35d47 | 1162 | force_flush = 1; |
6237bcd9 | 1163 | set_page_dirty(page); |
1cf35d47 | 1164 | } |
4917e5d0 | 1165 | if (pte_young(ptent) && |
64363aad | 1166 | likely(!(vma->vm_flags & VM_SEQ_READ))) |
bf3f3bc5 | 1167 | mark_page_accessed(page); |
6237bcd9 | 1168 | } |
eca56ff9 | 1169 | rss[mm_counter(page)]--; |
d281ee61 | 1170 | page_remove_rmap(page, false); |
3dc14741 HD |
1171 | if (unlikely(page_mapcount(page) < 0)) |
1172 | print_bad_pte(vma, addr, ptent, page); | |
e9d55e15 | 1173 | if (unlikely(__tlb_remove_page(tlb, page))) { |
1cf35d47 | 1174 | force_flush = 1; |
e9d55e15 | 1175 | pending_page = page; |
ce9ec37b | 1176 | addr += PAGE_SIZE; |
d16dfc55 | 1177 | break; |
1cf35d47 | 1178 | } |
1da177e4 LT |
1179 | continue; |
1180 | } | |
aac45363 MH |
1181 | /* only check swap_entries if explicitly asked for in details */ |
1182 | if (unlikely(details && !details->check_swap_entries)) | |
1da177e4 | 1183 | continue; |
b084d435 | 1184 | |
8a5f14a2 KS |
1185 | entry = pte_to_swp_entry(ptent); |
1186 | if (!non_swap_entry(entry)) | |
1187 | rss[MM_SWAPENTS]--; | |
1188 | else if (is_migration_entry(entry)) { | |
1189 | struct page *page; | |
9f9f1acd | 1190 | |
8a5f14a2 | 1191 | page = migration_entry_to_page(entry); |
eca56ff9 | 1192 | rss[mm_counter(page)]--; |
b084d435 | 1193 | } |
8a5f14a2 KS |
1194 | if (unlikely(!free_swap_and_cache(entry))) |
1195 | print_bad_pte(vma, addr, ptent, NULL); | |
9888a1ca | 1196 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); |
97a89413 | 1197 | } while (pte++, addr += PAGE_SIZE, addr != end); |
ae859762 | 1198 | |
d559db08 | 1199 | add_mm_rss_vec(mm, rss); |
6606c3e0 | 1200 | arch_leave_lazy_mmu_mode(); |
51c6f666 | 1201 | |
1cf35d47 | 1202 | /* Do the actual TLB flush before dropping ptl */ |
fb7332a9 | 1203 | if (force_flush) |
1cf35d47 | 1204 | tlb_flush_mmu_tlbonly(tlb); |
1cf35d47 LT |
1205 | pte_unmap_unlock(start_pte, ptl); |
1206 | ||
1207 | /* | |
1208 | * If we forced a TLB flush (either due to running out of | |
1209 | * batch buffers or because we needed to flush dirty TLB | |
1210 | * entries before releasing the ptl), free the batched | |
1211 | * memory too. Restart if we didn't do everything. | |
1212 | */ | |
1213 | if (force_flush) { | |
1214 | force_flush = 0; | |
1215 | tlb_flush_mmu_free(tlb); | |
e9d55e15 AK |
1216 | if (pending_page) { |
1217 | /* remove the page with new size */ | |
1218 | __tlb_remove_pte_page(tlb, pending_page); | |
1219 | pending_page = NULL; | |
1220 | } | |
2b047252 | 1221 | if (addr != end) |
d16dfc55 PZ |
1222 | goto again; |
1223 | } | |
1224 | ||
51c6f666 | 1225 | return addr; |
1da177e4 LT |
1226 | } |
1227 | ||
51c6f666 | 1228 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 1229 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 1230 | unsigned long addr, unsigned long end, |
97a89413 | 1231 | struct zap_details *details) |
1da177e4 LT |
1232 | { |
1233 | pmd_t *pmd; | |
1234 | unsigned long next; | |
1235 | ||
1236 | pmd = pmd_offset(pud, addr); | |
1237 | do { | |
1238 | next = pmd_addr_end(addr, end); | |
5c7fb56e | 1239 | if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) { |
1a5a9906 | 1240 | if (next - addr != HPAGE_PMD_SIZE) { |
68428398 HD |
1241 | VM_BUG_ON_VMA(vma_is_anonymous(vma) && |
1242 | !rwsem_is_locked(&tlb->mm->mmap_sem), vma); | |
78ddc534 | 1243 | split_huge_pmd(vma, pmd, addr); |
f21760b1 | 1244 | } else if (zap_huge_pmd(tlb, vma, pmd, addr)) |
1a5a9906 | 1245 | goto next; |
71e3aac0 AA |
1246 | /* fall through */ |
1247 | } | |
1a5a9906 AA |
1248 | /* |
1249 | * Here there can be other concurrent MADV_DONTNEED or | |
1250 | * trans huge page faults running, and if the pmd is | |
1251 | * none or trans huge it can change under us. This is | |
1252 | * because MADV_DONTNEED holds the mmap_sem in read | |
1253 | * mode. | |
1254 | */ | |
1255 | if (pmd_none_or_trans_huge_or_clear_bad(pmd)) | |
1256 | goto next; | |
97a89413 | 1257 | next = zap_pte_range(tlb, vma, pmd, addr, next, details); |
1a5a9906 | 1258 | next: |
97a89413 PZ |
1259 | cond_resched(); |
1260 | } while (pmd++, addr = next, addr != end); | |
51c6f666 RH |
1261 | |
1262 | return addr; | |
1da177e4 LT |
1263 | } |
1264 | ||
51c6f666 | 1265 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 1266 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 1267 | unsigned long addr, unsigned long end, |
97a89413 | 1268 | struct zap_details *details) |
1da177e4 LT |
1269 | { |
1270 | pud_t *pud; | |
1271 | unsigned long next; | |
1272 | ||
1273 | pud = pud_offset(pgd, addr); | |
1274 | do { | |
1275 | next = pud_addr_end(addr, end); | |
97a89413 | 1276 | if (pud_none_or_clear_bad(pud)) |
1da177e4 | 1277 | continue; |
97a89413 PZ |
1278 | next = zap_pmd_range(tlb, vma, pud, addr, next, details); |
1279 | } while (pud++, addr = next, addr != end); | |
51c6f666 RH |
1280 | |
1281 | return addr; | |
1da177e4 LT |
1282 | } |
1283 | ||
aac45363 | 1284 | void unmap_page_range(struct mmu_gather *tlb, |
038c7aa1 AV |
1285 | struct vm_area_struct *vma, |
1286 | unsigned long addr, unsigned long end, | |
1287 | struct zap_details *details) | |
1da177e4 LT |
1288 | { |
1289 | pgd_t *pgd; | |
1290 | unsigned long next; | |
1291 | ||
1da177e4 LT |
1292 | BUG_ON(addr >= end); |
1293 | tlb_start_vma(tlb, vma); | |
1294 | pgd = pgd_offset(vma->vm_mm, addr); | |
1295 | do { | |
1296 | next = pgd_addr_end(addr, end); | |
97a89413 | 1297 | if (pgd_none_or_clear_bad(pgd)) |
1da177e4 | 1298 | continue; |
97a89413 PZ |
1299 | next = zap_pud_range(tlb, vma, pgd, addr, next, details); |
1300 | } while (pgd++, addr = next, addr != end); | |
1da177e4 LT |
1301 | tlb_end_vma(tlb, vma); |
1302 | } | |
51c6f666 | 1303 | |
f5cc4eef AV |
1304 | |
1305 | static void unmap_single_vma(struct mmu_gather *tlb, | |
1306 | struct vm_area_struct *vma, unsigned long start_addr, | |
4f74d2c8 | 1307 | unsigned long end_addr, |
f5cc4eef AV |
1308 | struct zap_details *details) |
1309 | { | |
1310 | unsigned long start = max(vma->vm_start, start_addr); | |
1311 | unsigned long end; | |
1312 | ||
1313 | if (start >= vma->vm_end) | |
1314 | return; | |
1315 | end = min(vma->vm_end, end_addr); | |
1316 | if (end <= vma->vm_start) | |
1317 | return; | |
1318 | ||
cbc91f71 SD |
1319 | if (vma->vm_file) |
1320 | uprobe_munmap(vma, start, end); | |
1321 | ||
b3b9c293 | 1322 | if (unlikely(vma->vm_flags & VM_PFNMAP)) |
5180da41 | 1323 | untrack_pfn(vma, 0, 0); |
f5cc4eef AV |
1324 | |
1325 | if (start != end) { | |
1326 | if (unlikely(is_vm_hugetlb_page(vma))) { | |
1327 | /* | |
1328 | * It is undesirable to test vma->vm_file as it | |
1329 | * should be non-null for valid hugetlb area. | |
1330 | * However, vm_file will be NULL in the error | |
7aa6b4ad | 1331 | * cleanup path of mmap_region. When |
f5cc4eef | 1332 | * hugetlbfs ->mmap method fails, |
7aa6b4ad | 1333 | * mmap_region() nullifies vma->vm_file |
f5cc4eef AV |
1334 | * before calling this function to clean up. |
1335 | * Since no pte has actually been setup, it is | |
1336 | * safe to do nothing in this case. | |
1337 | */ | |
24669e58 | 1338 | if (vma->vm_file) { |
83cde9e8 | 1339 | i_mmap_lock_write(vma->vm_file->f_mapping); |
d833352a | 1340 | __unmap_hugepage_range_final(tlb, vma, start, end, NULL); |
83cde9e8 | 1341 | i_mmap_unlock_write(vma->vm_file->f_mapping); |
24669e58 | 1342 | } |
f5cc4eef AV |
1343 | } else |
1344 | unmap_page_range(tlb, vma, start, end, details); | |
1345 | } | |
1da177e4 LT |
1346 | } |
1347 | ||
1da177e4 LT |
1348 | /** |
1349 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
0164f69d | 1350 | * @tlb: address of the caller's struct mmu_gather |
1da177e4 LT |
1351 | * @vma: the starting vma |
1352 | * @start_addr: virtual address at which to start unmapping | |
1353 | * @end_addr: virtual address at which to end unmapping | |
1da177e4 | 1354 | * |
508034a3 | 1355 | * Unmap all pages in the vma list. |
1da177e4 | 1356 | * |
1da177e4 LT |
1357 | * Only addresses between `start' and `end' will be unmapped. |
1358 | * | |
1359 | * The VMA list must be sorted in ascending virtual address order. | |
1360 | * | |
1361 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
1362 | * range after unmap_vmas() returns. So the only responsibility here is to | |
1363 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
1364 | * drops the lock and schedules. | |
1365 | */ | |
6e8bb019 | 1366 | void unmap_vmas(struct mmu_gather *tlb, |
1da177e4 | 1367 | struct vm_area_struct *vma, unsigned long start_addr, |
4f74d2c8 | 1368 | unsigned long end_addr) |
1da177e4 | 1369 | { |
cddb8a5c | 1370 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1371 | |
cddb8a5c | 1372 | mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); |
f5cc4eef | 1373 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) |
4f74d2c8 | 1374 | unmap_single_vma(tlb, vma, start_addr, end_addr, NULL); |
cddb8a5c | 1375 | mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); |
1da177e4 LT |
1376 | } |
1377 | ||
1378 | /** | |
1379 | * zap_page_range - remove user pages in a given range | |
1380 | * @vma: vm_area_struct holding the applicable pages | |
eb4546bb | 1381 | * @start: starting address of pages to zap |
1da177e4 | 1382 | * @size: number of bytes to zap |
8a5f14a2 | 1383 | * @details: details of shared cache invalidation |
f5cc4eef AV |
1384 | * |
1385 | * Caller must protect the VMA list | |
1da177e4 | 1386 | */ |
7e027b14 | 1387 | void zap_page_range(struct vm_area_struct *vma, unsigned long start, |
1da177e4 LT |
1388 | unsigned long size, struct zap_details *details) |
1389 | { | |
1390 | struct mm_struct *mm = vma->vm_mm; | |
d16dfc55 | 1391 | struct mmu_gather tlb; |
7e027b14 | 1392 | unsigned long end = start + size; |
1da177e4 | 1393 | |
1da177e4 | 1394 | lru_add_drain(); |
2b047252 | 1395 | tlb_gather_mmu(&tlb, mm, start, end); |
365e9c87 | 1396 | update_hiwater_rss(mm); |
7e027b14 LT |
1397 | mmu_notifier_invalidate_range_start(mm, start, end); |
1398 | for ( ; vma && vma->vm_start < end; vma = vma->vm_next) | |
4f74d2c8 | 1399 | unmap_single_vma(&tlb, vma, start, end, details); |
7e027b14 LT |
1400 | mmu_notifier_invalidate_range_end(mm, start, end); |
1401 | tlb_finish_mmu(&tlb, start, end); | |
1da177e4 LT |
1402 | } |
1403 | ||
f5cc4eef AV |
1404 | /** |
1405 | * zap_page_range_single - remove user pages in a given range | |
1406 | * @vma: vm_area_struct holding the applicable pages | |
1407 | * @address: starting address of pages to zap | |
1408 | * @size: number of bytes to zap | |
8a5f14a2 | 1409 | * @details: details of shared cache invalidation |
f5cc4eef AV |
1410 | * |
1411 | * The range must fit into one VMA. | |
1da177e4 | 1412 | */ |
f5cc4eef | 1413 | static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
1414 | unsigned long size, struct zap_details *details) |
1415 | { | |
1416 | struct mm_struct *mm = vma->vm_mm; | |
d16dfc55 | 1417 | struct mmu_gather tlb; |
1da177e4 | 1418 | unsigned long end = address + size; |
1da177e4 | 1419 | |
1da177e4 | 1420 | lru_add_drain(); |
2b047252 | 1421 | tlb_gather_mmu(&tlb, mm, address, end); |
365e9c87 | 1422 | update_hiwater_rss(mm); |
f5cc4eef | 1423 | mmu_notifier_invalidate_range_start(mm, address, end); |
4f74d2c8 | 1424 | unmap_single_vma(&tlb, vma, address, end, details); |
f5cc4eef | 1425 | mmu_notifier_invalidate_range_end(mm, address, end); |
d16dfc55 | 1426 | tlb_finish_mmu(&tlb, address, end); |
1da177e4 LT |
1427 | } |
1428 | ||
c627f9cc JS |
1429 | /** |
1430 | * zap_vma_ptes - remove ptes mapping the vma | |
1431 | * @vma: vm_area_struct holding ptes to be zapped | |
1432 | * @address: starting address of pages to zap | |
1433 | * @size: number of bytes to zap | |
1434 | * | |
1435 | * This function only unmaps ptes assigned to VM_PFNMAP vmas. | |
1436 | * | |
1437 | * The entire address range must be fully contained within the vma. | |
1438 | * | |
1439 | * Returns 0 if successful. | |
1440 | */ | |
1441 | int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, | |
1442 | unsigned long size) | |
1443 | { | |
1444 | if (address < vma->vm_start || address + size > vma->vm_end || | |
1445 | !(vma->vm_flags & VM_PFNMAP)) | |
1446 | return -1; | |
f5cc4eef | 1447 | zap_page_range_single(vma, address, size, NULL); |
c627f9cc JS |
1448 | return 0; |
1449 | } | |
1450 | EXPORT_SYMBOL_GPL(zap_vma_ptes); | |
1451 | ||
25ca1d6c | 1452 | pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr, |
920c7a5d | 1453 | spinlock_t **ptl) |
c9cfcddf LT |
1454 | { |
1455 | pgd_t * pgd = pgd_offset(mm, addr); | |
1456 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
1457 | if (pud) { | |
49c91fb0 | 1458 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
f66055ab AA |
1459 | if (pmd) { |
1460 | VM_BUG_ON(pmd_trans_huge(*pmd)); | |
c9cfcddf | 1461 | return pte_alloc_map_lock(mm, pmd, addr, ptl); |
f66055ab | 1462 | } |
c9cfcddf LT |
1463 | } |
1464 | return NULL; | |
1465 | } | |
1466 | ||
238f58d8 LT |
1467 | /* |
1468 | * This is the old fallback for page remapping. | |
1469 | * | |
1470 | * For historical reasons, it only allows reserved pages. Only | |
1471 | * old drivers should use this, and they needed to mark their | |
1472 | * pages reserved for the old functions anyway. | |
1473 | */ | |
423bad60 NP |
1474 | static int insert_page(struct vm_area_struct *vma, unsigned long addr, |
1475 | struct page *page, pgprot_t prot) | |
238f58d8 | 1476 | { |
423bad60 | 1477 | struct mm_struct *mm = vma->vm_mm; |
238f58d8 | 1478 | int retval; |
c9cfcddf | 1479 | pte_t *pte; |
8a9f3ccd BS |
1480 | spinlock_t *ptl; |
1481 | ||
238f58d8 | 1482 | retval = -EINVAL; |
a145dd41 | 1483 | if (PageAnon(page)) |
5b4e655e | 1484 | goto out; |
238f58d8 LT |
1485 | retval = -ENOMEM; |
1486 | flush_dcache_page(page); | |
c9cfcddf | 1487 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 | 1488 | if (!pte) |
5b4e655e | 1489 | goto out; |
238f58d8 LT |
1490 | retval = -EBUSY; |
1491 | if (!pte_none(*pte)) | |
1492 | goto out_unlock; | |
1493 | ||
1494 | /* Ok, finally just insert the thing.. */ | |
1495 | get_page(page); | |
eca56ff9 | 1496 | inc_mm_counter_fast(mm, mm_counter_file(page)); |
dd78fedd | 1497 | page_add_file_rmap(page, false); |
238f58d8 LT |
1498 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); |
1499 | ||
1500 | retval = 0; | |
8a9f3ccd BS |
1501 | pte_unmap_unlock(pte, ptl); |
1502 | return retval; | |
238f58d8 LT |
1503 | out_unlock: |
1504 | pte_unmap_unlock(pte, ptl); | |
1505 | out: | |
1506 | return retval; | |
1507 | } | |
1508 | ||
bfa5bf6d REB |
1509 | /** |
1510 | * vm_insert_page - insert single page into user vma | |
1511 | * @vma: user vma to map to | |
1512 | * @addr: target user address of this page | |
1513 | * @page: source kernel page | |
1514 | * | |
a145dd41 LT |
1515 | * This allows drivers to insert individual pages they've allocated |
1516 | * into a user vma. | |
1517 | * | |
1518 | * The page has to be a nice clean _individual_ kernel allocation. | |
1519 | * If you allocate a compound page, you need to have marked it as | |
1520 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 1521 | * (see split_page()). |
a145dd41 LT |
1522 | * |
1523 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
1524 | * took an arbitrary page protection parameter. This doesn't allow | |
1525 | * that. Your vma protection will have to be set up correctly, which | |
1526 | * means that if you want a shared writable mapping, you'd better | |
1527 | * ask for a shared writable mapping! | |
1528 | * | |
1529 | * The page does not need to be reserved. | |
4b6e1e37 KK |
1530 | * |
1531 | * Usually this function is called from f_op->mmap() handler | |
1532 | * under mm->mmap_sem write-lock, so it can change vma->vm_flags. | |
1533 | * Caller must set VM_MIXEDMAP on vma if it wants to call this | |
1534 | * function from other places, for example from page-fault handler. | |
a145dd41 | 1535 | */ |
423bad60 NP |
1536 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
1537 | struct page *page) | |
a145dd41 LT |
1538 | { |
1539 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1540 | return -EFAULT; | |
1541 | if (!page_count(page)) | |
1542 | return -EINVAL; | |
4b6e1e37 KK |
1543 | if (!(vma->vm_flags & VM_MIXEDMAP)) { |
1544 | BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem)); | |
1545 | BUG_ON(vma->vm_flags & VM_PFNMAP); | |
1546 | vma->vm_flags |= VM_MIXEDMAP; | |
1547 | } | |
423bad60 | 1548 | return insert_page(vma, addr, page, vma->vm_page_prot); |
a145dd41 | 1549 | } |
e3c3374f | 1550 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 1551 | |
423bad60 | 1552 | static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, |
01c8f1c4 | 1553 | pfn_t pfn, pgprot_t prot) |
423bad60 NP |
1554 | { |
1555 | struct mm_struct *mm = vma->vm_mm; | |
1556 | int retval; | |
1557 | pte_t *pte, entry; | |
1558 | spinlock_t *ptl; | |
1559 | ||
1560 | retval = -ENOMEM; | |
1561 | pte = get_locked_pte(mm, addr, &ptl); | |
1562 | if (!pte) | |
1563 | goto out; | |
1564 | retval = -EBUSY; | |
1565 | if (!pte_none(*pte)) | |
1566 | goto out_unlock; | |
1567 | ||
1568 | /* Ok, finally just insert the thing.. */ | |
01c8f1c4 DW |
1569 | if (pfn_t_devmap(pfn)) |
1570 | entry = pte_mkdevmap(pfn_t_pte(pfn, prot)); | |
1571 | else | |
1572 | entry = pte_mkspecial(pfn_t_pte(pfn, prot)); | |
423bad60 | 1573 | set_pte_at(mm, addr, pte, entry); |
4b3073e1 | 1574 | update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */ |
423bad60 NP |
1575 | |
1576 | retval = 0; | |
1577 | out_unlock: | |
1578 | pte_unmap_unlock(pte, ptl); | |
1579 | out: | |
1580 | return retval; | |
1581 | } | |
1582 | ||
e0dc0d8f NP |
1583 | /** |
1584 | * vm_insert_pfn - insert single pfn into user vma | |
1585 | * @vma: user vma to map to | |
1586 | * @addr: target user address of this page | |
1587 | * @pfn: source kernel pfn | |
1588 | * | |
c462f179 | 1589 | * Similar to vm_insert_page, this allows drivers to insert individual pages |
e0dc0d8f NP |
1590 | * they've allocated into a user vma. Same comments apply. |
1591 | * | |
1592 | * This function should only be called from a vm_ops->fault handler, and | |
1593 | * in that case the handler should return NULL. | |
0d71d10a NP |
1594 | * |
1595 | * vma cannot be a COW mapping. | |
1596 | * | |
1597 | * As this is called only for pages that do not currently exist, we | |
1598 | * do not need to flush old virtual caches or the TLB. | |
e0dc0d8f NP |
1599 | */ |
1600 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
423bad60 | 1601 | unsigned long pfn) |
1745cbc5 AL |
1602 | { |
1603 | return vm_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot); | |
1604 | } | |
1605 | EXPORT_SYMBOL(vm_insert_pfn); | |
1606 | ||
1607 | /** | |
1608 | * vm_insert_pfn_prot - insert single pfn into user vma with specified pgprot | |
1609 | * @vma: user vma to map to | |
1610 | * @addr: target user address of this page | |
1611 | * @pfn: source kernel pfn | |
1612 | * @pgprot: pgprot flags for the inserted page | |
1613 | * | |
1614 | * This is exactly like vm_insert_pfn, except that it allows drivers to | |
1615 | * to override pgprot on a per-page basis. | |
1616 | * | |
1617 | * This only makes sense for IO mappings, and it makes no sense for | |
1618 | * cow mappings. In general, using multiple vmas is preferable; | |
1619 | * vm_insert_pfn_prot should only be used if using multiple VMAs is | |
1620 | * impractical. | |
1621 | */ | |
1622 | int vm_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr, | |
1623 | unsigned long pfn, pgprot_t pgprot) | |
e0dc0d8f | 1624 | { |
2ab64037 | 1625 | int ret; |
7e675137 NP |
1626 | /* |
1627 | * Technically, architectures with pte_special can avoid all these | |
1628 | * restrictions (same for remap_pfn_range). However we would like | |
1629 | * consistency in testing and feature parity among all, so we should | |
1630 | * try to keep these invariants in place for everybody. | |
1631 | */ | |
b379d790 JH |
1632 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); |
1633 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
1634 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1635 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
1636 | BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); | |
e0dc0d8f | 1637 | |
423bad60 NP |
1638 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1639 | return -EFAULT; | |
f25748e3 | 1640 | if (track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV))) |
2ab64037 | 1641 | return -EINVAL; |
1642 | ||
01c8f1c4 | 1643 | ret = insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot); |
2ab64037 | 1644 | |
2ab64037 | 1645 | return ret; |
423bad60 | 1646 | } |
1745cbc5 | 1647 | EXPORT_SYMBOL(vm_insert_pfn_prot); |
e0dc0d8f | 1648 | |
423bad60 | 1649 | int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, |
01c8f1c4 | 1650 | pfn_t pfn) |
423bad60 | 1651 | { |
87744ab3 DW |
1652 | pgprot_t pgprot = vma->vm_page_prot; |
1653 | ||
423bad60 | 1654 | BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); |
e0dc0d8f | 1655 | |
423bad60 NP |
1656 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1657 | return -EFAULT; | |
87744ab3 DW |
1658 | if (track_pfn_insert(vma, &pgprot, pfn)) |
1659 | return -EINVAL; | |
e0dc0d8f | 1660 | |
423bad60 NP |
1661 | /* |
1662 | * If we don't have pte special, then we have to use the pfn_valid() | |
1663 | * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* | |
1664 | * refcount the page if pfn_valid is true (hence insert_page rather | |
62eede62 HD |
1665 | * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP |
1666 | * without pte special, it would there be refcounted as a normal page. | |
423bad60 | 1667 | */ |
03fc2da6 | 1668 | if (!HAVE_PTE_SPECIAL && !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) { |
423bad60 NP |
1669 | struct page *page; |
1670 | ||
03fc2da6 DW |
1671 | /* |
1672 | * At this point we are committed to insert_page() | |
1673 | * regardless of whether the caller specified flags that | |
1674 | * result in pfn_t_has_page() == false. | |
1675 | */ | |
1676 | page = pfn_to_page(pfn_t_to_pfn(pfn)); | |
87744ab3 | 1677 | return insert_page(vma, addr, page, pgprot); |
423bad60 | 1678 | } |
87744ab3 | 1679 | return insert_pfn(vma, addr, pfn, pgprot); |
e0dc0d8f | 1680 | } |
423bad60 | 1681 | EXPORT_SYMBOL(vm_insert_mixed); |
e0dc0d8f | 1682 | |
1da177e4 LT |
1683 | /* |
1684 | * maps a range of physical memory into the requested pages. the old | |
1685 | * mappings are removed. any references to nonexistent pages results | |
1686 | * in null mappings (currently treated as "copy-on-access") | |
1687 | */ | |
1688 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
1689 | unsigned long addr, unsigned long end, | |
1690 | unsigned long pfn, pgprot_t prot) | |
1691 | { | |
1692 | pte_t *pte; | |
c74df32c | 1693 | spinlock_t *ptl; |
1da177e4 | 1694 | |
c74df32c | 1695 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
1696 | if (!pte) |
1697 | return -ENOMEM; | |
6606c3e0 | 1698 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1699 | do { |
1700 | BUG_ON(!pte_none(*pte)); | |
7e675137 | 1701 | set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); |
1da177e4 LT |
1702 | pfn++; |
1703 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 1704 | arch_leave_lazy_mmu_mode(); |
c74df32c | 1705 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
1706 | return 0; |
1707 | } | |
1708 | ||
1709 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1710 | unsigned long addr, unsigned long end, | |
1711 | unsigned long pfn, pgprot_t prot) | |
1712 | { | |
1713 | pmd_t *pmd; | |
1714 | unsigned long next; | |
1715 | ||
1716 | pfn -= addr >> PAGE_SHIFT; | |
1717 | pmd = pmd_alloc(mm, pud, addr); | |
1718 | if (!pmd) | |
1719 | return -ENOMEM; | |
f66055ab | 1720 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
1da177e4 LT |
1721 | do { |
1722 | next = pmd_addr_end(addr, end); | |
1723 | if (remap_pte_range(mm, pmd, addr, next, | |
1724 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1725 | return -ENOMEM; | |
1726 | } while (pmd++, addr = next, addr != end); | |
1727 | return 0; | |
1728 | } | |
1729 | ||
1730 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1731 | unsigned long addr, unsigned long end, | |
1732 | unsigned long pfn, pgprot_t prot) | |
1733 | { | |
1734 | pud_t *pud; | |
1735 | unsigned long next; | |
1736 | ||
1737 | pfn -= addr >> PAGE_SHIFT; | |
1738 | pud = pud_alloc(mm, pgd, addr); | |
1739 | if (!pud) | |
1740 | return -ENOMEM; | |
1741 | do { | |
1742 | next = pud_addr_end(addr, end); | |
1743 | if (remap_pmd_range(mm, pud, addr, next, | |
1744 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1745 | return -ENOMEM; | |
1746 | } while (pud++, addr = next, addr != end); | |
1747 | return 0; | |
1748 | } | |
1749 | ||
bfa5bf6d REB |
1750 | /** |
1751 | * remap_pfn_range - remap kernel memory to userspace | |
1752 | * @vma: user vma to map to | |
1753 | * @addr: target user address to start at | |
1754 | * @pfn: physical address of kernel memory | |
1755 | * @size: size of map area | |
1756 | * @prot: page protection flags for this mapping | |
1757 | * | |
1758 | * Note: this is only safe if the mm semaphore is held when called. | |
1759 | */ | |
1da177e4 LT |
1760 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
1761 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
1762 | { | |
1763 | pgd_t *pgd; | |
1764 | unsigned long next; | |
2d15cab8 | 1765 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 | 1766 | struct mm_struct *mm = vma->vm_mm; |
d5957d2f | 1767 | unsigned long remap_pfn = pfn; |
1da177e4 LT |
1768 | int err; |
1769 | ||
1770 | /* | |
1771 | * Physically remapped pages are special. Tell the | |
1772 | * rest of the world about it: | |
1773 | * VM_IO tells people not to look at these pages | |
1774 | * (accesses can have side effects). | |
6aab341e LT |
1775 | * VM_PFNMAP tells the core MM that the base pages are just |
1776 | * raw PFN mappings, and do not have a "struct page" associated | |
1777 | * with them. | |
314e51b9 KK |
1778 | * VM_DONTEXPAND |
1779 | * Disable vma merging and expanding with mremap(). | |
1780 | * VM_DONTDUMP | |
1781 | * Omit vma from core dump, even when VM_IO turned off. | |
fb155c16 LT |
1782 | * |
1783 | * There's a horrible special case to handle copy-on-write | |
1784 | * behaviour that some programs depend on. We mark the "original" | |
1785 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
b3b9c293 | 1786 | * See vm_normal_page() for details. |
1da177e4 | 1787 | */ |
b3b9c293 KK |
1788 | if (is_cow_mapping(vma->vm_flags)) { |
1789 | if (addr != vma->vm_start || end != vma->vm_end) | |
1790 | return -EINVAL; | |
fb155c16 | 1791 | vma->vm_pgoff = pfn; |
b3b9c293 KK |
1792 | } |
1793 | ||
d5957d2f | 1794 | err = track_pfn_remap(vma, &prot, remap_pfn, addr, PAGE_ALIGN(size)); |
b3b9c293 | 1795 | if (err) |
3c8bb73a | 1796 | return -EINVAL; |
fb155c16 | 1797 | |
314e51b9 | 1798 | vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP; |
1da177e4 LT |
1799 | |
1800 | BUG_ON(addr >= end); | |
1801 | pfn -= addr >> PAGE_SHIFT; | |
1802 | pgd = pgd_offset(mm, addr); | |
1803 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
1804 | do { |
1805 | next = pgd_addr_end(addr, end); | |
1806 | err = remap_pud_range(mm, pgd, addr, next, | |
1807 | pfn + (addr >> PAGE_SHIFT), prot); | |
1808 | if (err) | |
1809 | break; | |
1810 | } while (pgd++, addr = next, addr != end); | |
2ab64037 | 1811 | |
1812 | if (err) | |
d5957d2f | 1813 | untrack_pfn(vma, remap_pfn, PAGE_ALIGN(size)); |
2ab64037 | 1814 | |
1da177e4 LT |
1815 | return err; |
1816 | } | |
1817 | EXPORT_SYMBOL(remap_pfn_range); | |
1818 | ||
b4cbb197 LT |
1819 | /** |
1820 | * vm_iomap_memory - remap memory to userspace | |
1821 | * @vma: user vma to map to | |
1822 | * @start: start of area | |
1823 | * @len: size of area | |
1824 | * | |
1825 | * This is a simplified io_remap_pfn_range() for common driver use. The | |
1826 | * driver just needs to give us the physical memory range to be mapped, | |
1827 | * we'll figure out the rest from the vma information. | |
1828 | * | |
1829 | * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get | |
1830 | * whatever write-combining details or similar. | |
1831 | */ | |
1832 | int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len) | |
1833 | { | |
1834 | unsigned long vm_len, pfn, pages; | |
1835 | ||
1836 | /* Check that the physical memory area passed in looks valid */ | |
1837 | if (start + len < start) | |
1838 | return -EINVAL; | |
1839 | /* | |
1840 | * You *really* shouldn't map things that aren't page-aligned, | |
1841 | * but we've historically allowed it because IO memory might | |
1842 | * just have smaller alignment. | |
1843 | */ | |
1844 | len += start & ~PAGE_MASK; | |
1845 | pfn = start >> PAGE_SHIFT; | |
1846 | pages = (len + ~PAGE_MASK) >> PAGE_SHIFT; | |
1847 | if (pfn + pages < pfn) | |
1848 | return -EINVAL; | |
1849 | ||
1850 | /* We start the mapping 'vm_pgoff' pages into the area */ | |
1851 | if (vma->vm_pgoff > pages) | |
1852 | return -EINVAL; | |
1853 | pfn += vma->vm_pgoff; | |
1854 | pages -= vma->vm_pgoff; | |
1855 | ||
1856 | /* Can we fit all of the mapping? */ | |
1857 | vm_len = vma->vm_end - vma->vm_start; | |
1858 | if (vm_len >> PAGE_SHIFT > pages) | |
1859 | return -EINVAL; | |
1860 | ||
1861 | /* Ok, let it rip */ | |
1862 | return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot); | |
1863 | } | |
1864 | EXPORT_SYMBOL(vm_iomap_memory); | |
1865 | ||
aee16b3c JF |
1866 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
1867 | unsigned long addr, unsigned long end, | |
1868 | pte_fn_t fn, void *data) | |
1869 | { | |
1870 | pte_t *pte; | |
1871 | int err; | |
2f569afd | 1872 | pgtable_t token; |
94909914 | 1873 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
1874 | |
1875 | pte = (mm == &init_mm) ? | |
1876 | pte_alloc_kernel(pmd, addr) : | |
1877 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
1878 | if (!pte) | |
1879 | return -ENOMEM; | |
1880 | ||
1881 | BUG_ON(pmd_huge(*pmd)); | |
1882 | ||
38e0edb1 JF |
1883 | arch_enter_lazy_mmu_mode(); |
1884 | ||
2f569afd | 1885 | token = pmd_pgtable(*pmd); |
aee16b3c JF |
1886 | |
1887 | do { | |
c36987e2 | 1888 | err = fn(pte++, token, addr, data); |
aee16b3c JF |
1889 | if (err) |
1890 | break; | |
c36987e2 | 1891 | } while (addr += PAGE_SIZE, addr != end); |
aee16b3c | 1892 | |
38e0edb1 JF |
1893 | arch_leave_lazy_mmu_mode(); |
1894 | ||
aee16b3c JF |
1895 | if (mm != &init_mm) |
1896 | pte_unmap_unlock(pte-1, ptl); | |
1897 | return err; | |
1898 | } | |
1899 | ||
1900 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1901 | unsigned long addr, unsigned long end, | |
1902 | pte_fn_t fn, void *data) | |
1903 | { | |
1904 | pmd_t *pmd; | |
1905 | unsigned long next; | |
1906 | int err; | |
1907 | ||
ceb86879 AK |
1908 | BUG_ON(pud_huge(*pud)); |
1909 | ||
aee16b3c JF |
1910 | pmd = pmd_alloc(mm, pud, addr); |
1911 | if (!pmd) | |
1912 | return -ENOMEM; | |
1913 | do { | |
1914 | next = pmd_addr_end(addr, end); | |
1915 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
1916 | if (err) | |
1917 | break; | |
1918 | } while (pmd++, addr = next, addr != end); | |
1919 | return err; | |
1920 | } | |
1921 | ||
1922 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1923 | unsigned long addr, unsigned long end, | |
1924 | pte_fn_t fn, void *data) | |
1925 | { | |
1926 | pud_t *pud; | |
1927 | unsigned long next; | |
1928 | int err; | |
1929 | ||
1930 | pud = pud_alloc(mm, pgd, addr); | |
1931 | if (!pud) | |
1932 | return -ENOMEM; | |
1933 | do { | |
1934 | next = pud_addr_end(addr, end); | |
1935 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
1936 | if (err) | |
1937 | break; | |
1938 | } while (pud++, addr = next, addr != end); | |
1939 | return err; | |
1940 | } | |
1941 | ||
1942 | /* | |
1943 | * Scan a region of virtual memory, filling in page tables as necessary | |
1944 | * and calling a provided function on each leaf page table. | |
1945 | */ | |
1946 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
1947 | unsigned long size, pte_fn_t fn, void *data) | |
1948 | { | |
1949 | pgd_t *pgd; | |
1950 | unsigned long next; | |
57250a5b | 1951 | unsigned long end = addr + size; |
aee16b3c JF |
1952 | int err; |
1953 | ||
9cb65bc3 MP |
1954 | if (WARN_ON(addr >= end)) |
1955 | return -EINVAL; | |
1956 | ||
aee16b3c JF |
1957 | pgd = pgd_offset(mm, addr); |
1958 | do { | |
1959 | next = pgd_addr_end(addr, end); | |
1960 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
1961 | if (err) | |
1962 | break; | |
1963 | } while (pgd++, addr = next, addr != end); | |
57250a5b | 1964 | |
aee16b3c JF |
1965 | return err; |
1966 | } | |
1967 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
1968 | ||
8f4e2101 | 1969 | /* |
9b4bdd2f KS |
1970 | * handle_pte_fault chooses page fault handler according to an entry which was |
1971 | * read non-atomically. Before making any commitment, on those architectures | |
1972 | * or configurations (e.g. i386 with PAE) which might give a mix of unmatched | |
1973 | * parts, do_swap_page must check under lock before unmapping the pte and | |
1974 | * proceeding (but do_wp_page is only called after already making such a check; | |
a335b2e1 | 1975 | * and do_anonymous_page can safely check later on). |
8f4e2101 | 1976 | */ |
4c21e2f2 | 1977 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
1978 | pte_t *page_table, pte_t orig_pte) |
1979 | { | |
1980 | int same = 1; | |
1981 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
1982 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
1983 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
1984 | spin_lock(ptl); | |
8f4e2101 | 1985 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 1986 | spin_unlock(ptl); |
8f4e2101 HD |
1987 | } |
1988 | #endif | |
1989 | pte_unmap(page_table); | |
1990 | return same; | |
1991 | } | |
1992 | ||
9de455b2 | 1993 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e | 1994 | { |
0abdd7a8 DW |
1995 | debug_dma_assert_idle(src); |
1996 | ||
6aab341e LT |
1997 | /* |
1998 | * If the source page was a PFN mapping, we don't have | |
1999 | * a "struct page" for it. We do a best-effort copy by | |
2000 | * just copying from the original user address. If that | |
2001 | * fails, we just zero-fill it. Live with it. | |
2002 | */ | |
2003 | if (unlikely(!src)) { | |
9b04c5fe | 2004 | void *kaddr = kmap_atomic(dst); |
5d2a2dbb LT |
2005 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
2006 | ||
2007 | /* | |
2008 | * This really shouldn't fail, because the page is there | |
2009 | * in the page tables. But it might just be unreadable, | |
2010 | * in which case we just give up and fill the result with | |
2011 | * zeroes. | |
2012 | */ | |
2013 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
3ecb01df | 2014 | clear_page(kaddr); |
9b04c5fe | 2015 | kunmap_atomic(kaddr); |
c4ec7b0d | 2016 | flush_dcache_page(dst); |
0ed361de NP |
2017 | } else |
2018 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
2019 | } |
2020 | ||
c20cd45e MH |
2021 | static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma) |
2022 | { | |
2023 | struct file *vm_file = vma->vm_file; | |
2024 | ||
2025 | if (vm_file) | |
2026 | return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO; | |
2027 | ||
2028 | /* | |
2029 | * Special mappings (e.g. VDSO) do not have any file so fake | |
2030 | * a default GFP_KERNEL for them. | |
2031 | */ | |
2032 | return GFP_KERNEL; | |
2033 | } | |
2034 | ||
fb09a464 KS |
2035 | /* |
2036 | * Notify the address space that the page is about to become writable so that | |
2037 | * it can prohibit this or wait for the page to get into an appropriate state. | |
2038 | * | |
2039 | * We do this without the lock held, so that it can sleep if it needs to. | |
2040 | */ | |
2041 | static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page, | |
2042 | unsigned long address) | |
2043 | { | |
2044 | struct vm_fault vmf; | |
2045 | int ret; | |
2046 | ||
2047 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); | |
2048 | vmf.pgoff = page->index; | |
2049 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; | |
c20cd45e | 2050 | vmf.gfp_mask = __get_fault_gfp_mask(vma); |
fb09a464 | 2051 | vmf.page = page; |
2e4cdab0 | 2052 | vmf.cow_page = NULL; |
fb09a464 KS |
2053 | |
2054 | ret = vma->vm_ops->page_mkwrite(vma, &vmf); | |
2055 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) | |
2056 | return ret; | |
2057 | if (unlikely(!(ret & VM_FAULT_LOCKED))) { | |
2058 | lock_page(page); | |
2059 | if (!page->mapping) { | |
2060 | unlock_page(page); | |
2061 | return 0; /* retry */ | |
2062 | } | |
2063 | ret |= VM_FAULT_LOCKED; | |
2064 | } else | |
2065 | VM_BUG_ON_PAGE(!PageLocked(page), page); | |
2066 | return ret; | |
2067 | } | |
2068 | ||
4e047f89 SR |
2069 | /* |
2070 | * Handle write page faults for pages that can be reused in the current vma | |
2071 | * | |
2072 | * This can happen either due to the mapping being with the VM_SHARED flag, | |
2073 | * or due to us being the last reference standing to the page. In either | |
2074 | * case, all we need to do here is to mark the page as writable and update | |
2075 | * any related book-keeping. | |
2076 | */ | |
bae473a4 KS |
2077 | static inline int wp_page_reuse(struct fault_env *fe, pte_t orig_pte, |
2078 | struct page *page, int page_mkwrite, int dirty_shared) | |
2079 | __releases(fe->ptl) | |
4e047f89 | 2080 | { |
bae473a4 | 2081 | struct vm_area_struct *vma = fe->vma; |
4e047f89 SR |
2082 | pte_t entry; |
2083 | /* | |
2084 | * Clear the pages cpupid information as the existing | |
2085 | * information potentially belongs to a now completely | |
2086 | * unrelated process. | |
2087 | */ | |
2088 | if (page) | |
2089 | page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1); | |
2090 | ||
bae473a4 | 2091 | flush_cache_page(vma, fe->address, pte_pfn(orig_pte)); |
4e047f89 SR |
2092 | entry = pte_mkyoung(orig_pte); |
2093 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
bae473a4 KS |
2094 | if (ptep_set_access_flags(vma, fe->address, fe->pte, entry, 1)) |
2095 | update_mmu_cache(vma, fe->address, fe->pte); | |
2096 | pte_unmap_unlock(fe->pte, fe->ptl); | |
4e047f89 SR |
2097 | |
2098 | if (dirty_shared) { | |
2099 | struct address_space *mapping; | |
2100 | int dirtied; | |
2101 | ||
2102 | if (!page_mkwrite) | |
2103 | lock_page(page); | |
2104 | ||
2105 | dirtied = set_page_dirty(page); | |
2106 | VM_BUG_ON_PAGE(PageAnon(page), page); | |
2107 | mapping = page->mapping; | |
2108 | unlock_page(page); | |
09cbfeaf | 2109 | put_page(page); |
4e047f89 SR |
2110 | |
2111 | if ((dirtied || page_mkwrite) && mapping) { | |
2112 | /* | |
2113 | * Some device drivers do not set page.mapping | |
2114 | * but still dirty their pages | |
2115 | */ | |
2116 | balance_dirty_pages_ratelimited(mapping); | |
2117 | } | |
2118 | ||
2119 | if (!page_mkwrite) | |
2120 | file_update_time(vma->vm_file); | |
2121 | } | |
2122 | ||
2123 | return VM_FAULT_WRITE; | |
2124 | } | |
2125 | ||
2f38ab2c SR |
2126 | /* |
2127 | * Handle the case of a page which we actually need to copy to a new page. | |
2128 | * | |
2129 | * Called with mmap_sem locked and the old page referenced, but | |
2130 | * without the ptl held. | |
2131 | * | |
2132 | * High level logic flow: | |
2133 | * | |
2134 | * - Allocate a page, copy the content of the old page to the new one. | |
2135 | * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc. | |
2136 | * - Take the PTL. If the pte changed, bail out and release the allocated page | |
2137 | * - If the pte is still the way we remember it, update the page table and all | |
2138 | * relevant references. This includes dropping the reference the page-table | |
2139 | * held to the old page, as well as updating the rmap. | |
2140 | * - In any case, unlock the PTL and drop the reference we took to the old page. | |
2141 | */ | |
bae473a4 KS |
2142 | static int wp_page_copy(struct fault_env *fe, pte_t orig_pte, |
2143 | struct page *old_page) | |
2f38ab2c | 2144 | { |
bae473a4 KS |
2145 | struct vm_area_struct *vma = fe->vma; |
2146 | struct mm_struct *mm = vma->vm_mm; | |
2f38ab2c | 2147 | struct page *new_page = NULL; |
2f38ab2c SR |
2148 | pte_t entry; |
2149 | int page_copied = 0; | |
bae473a4 KS |
2150 | const unsigned long mmun_start = fe->address & PAGE_MASK; |
2151 | const unsigned long mmun_end = mmun_start + PAGE_SIZE; | |
2f38ab2c SR |
2152 | struct mem_cgroup *memcg; |
2153 | ||
2154 | if (unlikely(anon_vma_prepare(vma))) | |
2155 | goto oom; | |
2156 | ||
2157 | if (is_zero_pfn(pte_pfn(orig_pte))) { | |
bae473a4 | 2158 | new_page = alloc_zeroed_user_highpage_movable(vma, fe->address); |
2f38ab2c SR |
2159 | if (!new_page) |
2160 | goto oom; | |
2161 | } else { | |
bae473a4 KS |
2162 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, |
2163 | fe->address); | |
2f38ab2c SR |
2164 | if (!new_page) |
2165 | goto oom; | |
bae473a4 | 2166 | cow_user_page(new_page, old_page, fe->address, vma); |
2f38ab2c | 2167 | } |
2f38ab2c | 2168 | |
f627c2f5 | 2169 | if (mem_cgroup_try_charge(new_page, mm, GFP_KERNEL, &memcg, false)) |
2f38ab2c SR |
2170 | goto oom_free_new; |
2171 | ||
eb3c24f3 MG |
2172 | __SetPageUptodate(new_page); |
2173 | ||
2f38ab2c SR |
2174 | mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); |
2175 | ||
2176 | /* | |
2177 | * Re-check the pte - we dropped the lock | |
2178 | */ | |
bae473a4 KS |
2179 | fe->pte = pte_offset_map_lock(mm, fe->pmd, fe->address, &fe->ptl); |
2180 | if (likely(pte_same(*fe->pte, orig_pte))) { | |
2f38ab2c SR |
2181 | if (old_page) { |
2182 | if (!PageAnon(old_page)) { | |
eca56ff9 JM |
2183 | dec_mm_counter_fast(mm, |
2184 | mm_counter_file(old_page)); | |
2f38ab2c SR |
2185 | inc_mm_counter_fast(mm, MM_ANONPAGES); |
2186 | } | |
2187 | } else { | |
2188 | inc_mm_counter_fast(mm, MM_ANONPAGES); | |
2189 | } | |
bae473a4 | 2190 | flush_cache_page(vma, fe->address, pte_pfn(orig_pte)); |
2f38ab2c SR |
2191 | entry = mk_pte(new_page, vma->vm_page_prot); |
2192 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
2193 | /* | |
2194 | * Clear the pte entry and flush it first, before updating the | |
2195 | * pte with the new entry. This will avoid a race condition | |
2196 | * seen in the presence of one thread doing SMC and another | |
2197 | * thread doing COW. | |
2198 | */ | |
bae473a4 KS |
2199 | ptep_clear_flush_notify(vma, fe->address, fe->pte); |
2200 | page_add_new_anon_rmap(new_page, vma, fe->address, false); | |
f627c2f5 | 2201 | mem_cgroup_commit_charge(new_page, memcg, false, false); |
2f38ab2c SR |
2202 | lru_cache_add_active_or_unevictable(new_page, vma); |
2203 | /* | |
2204 | * We call the notify macro here because, when using secondary | |
2205 | * mmu page tables (such as kvm shadow page tables), we want the | |
2206 | * new page to be mapped directly into the secondary page table. | |
2207 | */ | |
bae473a4 KS |
2208 | set_pte_at_notify(mm, fe->address, fe->pte, entry); |
2209 | update_mmu_cache(vma, fe->address, fe->pte); | |
2f38ab2c SR |
2210 | if (old_page) { |
2211 | /* | |
2212 | * Only after switching the pte to the new page may | |
2213 | * we remove the mapcount here. Otherwise another | |
2214 | * process may come and find the rmap count decremented | |
2215 | * before the pte is switched to the new page, and | |
2216 | * "reuse" the old page writing into it while our pte | |
2217 | * here still points into it and can be read by other | |
2218 | * threads. | |
2219 | * | |
2220 | * The critical issue is to order this | |
2221 | * page_remove_rmap with the ptp_clear_flush above. | |
2222 | * Those stores are ordered by (if nothing else,) | |
2223 | * the barrier present in the atomic_add_negative | |
2224 | * in page_remove_rmap. | |
2225 | * | |
2226 | * Then the TLB flush in ptep_clear_flush ensures that | |
2227 | * no process can access the old page before the | |
2228 | * decremented mapcount is visible. And the old page | |
2229 | * cannot be reused until after the decremented | |
2230 | * mapcount is visible. So transitively, TLBs to | |
2231 | * old page will be flushed before it can be reused. | |
2232 | */ | |
d281ee61 | 2233 | page_remove_rmap(old_page, false); |
2f38ab2c SR |
2234 | } |
2235 | ||
2236 | /* Free the old page.. */ | |
2237 | new_page = old_page; | |
2238 | page_copied = 1; | |
2239 | } else { | |
f627c2f5 | 2240 | mem_cgroup_cancel_charge(new_page, memcg, false); |
2f38ab2c SR |
2241 | } |
2242 | ||
2243 | if (new_page) | |
09cbfeaf | 2244 | put_page(new_page); |
2f38ab2c | 2245 | |
bae473a4 | 2246 | pte_unmap_unlock(fe->pte, fe->ptl); |
2f38ab2c SR |
2247 | mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); |
2248 | if (old_page) { | |
2249 | /* | |
2250 | * Don't let another task, with possibly unlocked vma, | |
2251 | * keep the mlocked page. | |
2252 | */ | |
2253 | if (page_copied && (vma->vm_flags & VM_LOCKED)) { | |
2254 | lock_page(old_page); /* LRU manipulation */ | |
e90309c9 KS |
2255 | if (PageMlocked(old_page)) |
2256 | munlock_vma_page(old_page); | |
2f38ab2c SR |
2257 | unlock_page(old_page); |
2258 | } | |
09cbfeaf | 2259 | put_page(old_page); |
2f38ab2c SR |
2260 | } |
2261 | return page_copied ? VM_FAULT_WRITE : 0; | |
2262 | oom_free_new: | |
09cbfeaf | 2263 | put_page(new_page); |
2f38ab2c SR |
2264 | oom: |
2265 | if (old_page) | |
09cbfeaf | 2266 | put_page(old_page); |
2f38ab2c SR |
2267 | return VM_FAULT_OOM; |
2268 | } | |
2269 | ||
dd906184 BH |
2270 | /* |
2271 | * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED | |
2272 | * mapping | |
2273 | */ | |
bae473a4 | 2274 | static int wp_pfn_shared(struct fault_env *fe, pte_t orig_pte) |
dd906184 | 2275 | { |
bae473a4 KS |
2276 | struct vm_area_struct *vma = fe->vma; |
2277 | ||
dd906184 BH |
2278 | if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) { |
2279 | struct vm_fault vmf = { | |
2280 | .page = NULL, | |
bae473a4 KS |
2281 | .pgoff = linear_page_index(vma, fe->address), |
2282 | .virtual_address = | |
2283 | (void __user *)(fe->address & PAGE_MASK), | |
dd906184 BH |
2284 | .flags = FAULT_FLAG_WRITE | FAULT_FLAG_MKWRITE, |
2285 | }; | |
2286 | int ret; | |
2287 | ||
bae473a4 | 2288 | pte_unmap_unlock(fe->pte, fe->ptl); |
dd906184 BH |
2289 | ret = vma->vm_ops->pfn_mkwrite(vma, &vmf); |
2290 | if (ret & VM_FAULT_ERROR) | |
2291 | return ret; | |
bae473a4 KS |
2292 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address, |
2293 | &fe->ptl); | |
dd906184 BH |
2294 | /* |
2295 | * We might have raced with another page fault while we | |
2296 | * released the pte_offset_map_lock. | |
2297 | */ | |
bae473a4 KS |
2298 | if (!pte_same(*fe->pte, orig_pte)) { |
2299 | pte_unmap_unlock(fe->pte, fe->ptl); | |
dd906184 BH |
2300 | return 0; |
2301 | } | |
2302 | } | |
bae473a4 | 2303 | return wp_page_reuse(fe, orig_pte, NULL, 0, 0); |
dd906184 BH |
2304 | } |
2305 | ||
bae473a4 KS |
2306 | static int wp_page_shared(struct fault_env *fe, pte_t orig_pte, |
2307 | struct page *old_page) | |
2308 | __releases(fe->ptl) | |
93e478d4 | 2309 | { |
bae473a4 | 2310 | struct vm_area_struct *vma = fe->vma; |
93e478d4 SR |
2311 | int page_mkwrite = 0; |
2312 | ||
09cbfeaf | 2313 | get_page(old_page); |
93e478d4 | 2314 | |
93e478d4 SR |
2315 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
2316 | int tmp; | |
2317 | ||
bae473a4 KS |
2318 | pte_unmap_unlock(fe->pte, fe->ptl); |
2319 | tmp = do_page_mkwrite(vma, old_page, fe->address); | |
93e478d4 SR |
2320 | if (unlikely(!tmp || (tmp & |
2321 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { | |
09cbfeaf | 2322 | put_page(old_page); |
93e478d4 SR |
2323 | return tmp; |
2324 | } | |
2325 | /* | |
2326 | * Since we dropped the lock we need to revalidate | |
2327 | * the PTE as someone else may have changed it. If | |
2328 | * they did, we just return, as we can count on the | |
2329 | * MMU to tell us if they didn't also make it writable. | |
2330 | */ | |
bae473a4 KS |
2331 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address, |
2332 | &fe->ptl); | |
2333 | if (!pte_same(*fe->pte, orig_pte)) { | |
93e478d4 | 2334 | unlock_page(old_page); |
bae473a4 | 2335 | pte_unmap_unlock(fe->pte, fe->ptl); |
09cbfeaf | 2336 | put_page(old_page); |
93e478d4 SR |
2337 | return 0; |
2338 | } | |
2339 | page_mkwrite = 1; | |
2340 | } | |
2341 | ||
bae473a4 | 2342 | return wp_page_reuse(fe, orig_pte, old_page, page_mkwrite, 1); |
93e478d4 SR |
2343 | } |
2344 | ||
1da177e4 LT |
2345 | /* |
2346 | * This routine handles present pages, when users try to write | |
2347 | * to a shared page. It is done by copying the page to a new address | |
2348 | * and decrementing the shared-page counter for the old page. | |
2349 | * | |
1da177e4 LT |
2350 | * Note that this routine assumes that the protection checks have been |
2351 | * done by the caller (the low-level page fault routine in most cases). | |
2352 | * Thus we can safely just mark it writable once we've done any necessary | |
2353 | * COW. | |
2354 | * | |
2355 | * We also mark the page dirty at this point even though the page will | |
2356 | * change only once the write actually happens. This avoids a few races, | |
2357 | * and potentially makes it more efficient. | |
2358 | * | |
8f4e2101 HD |
2359 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2360 | * but allow concurrent faults), with pte both mapped and locked. | |
2361 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2362 | */ |
bae473a4 KS |
2363 | static int do_wp_page(struct fault_env *fe, pte_t orig_pte) |
2364 | __releases(fe->ptl) | |
1da177e4 | 2365 | { |
bae473a4 | 2366 | struct vm_area_struct *vma = fe->vma; |
2f38ab2c | 2367 | struct page *old_page; |
1da177e4 | 2368 | |
bae473a4 | 2369 | old_page = vm_normal_page(vma, fe->address, orig_pte); |
251b97f5 PZ |
2370 | if (!old_page) { |
2371 | /* | |
64e45507 PF |
2372 | * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a |
2373 | * VM_PFNMAP VMA. | |
251b97f5 PZ |
2374 | * |
2375 | * We should not cow pages in a shared writeable mapping. | |
dd906184 | 2376 | * Just mark the pages writable and/or call ops->pfn_mkwrite. |
251b97f5 PZ |
2377 | */ |
2378 | if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
2379 | (VM_WRITE|VM_SHARED)) | |
bae473a4 | 2380 | return wp_pfn_shared(fe, orig_pte); |
2f38ab2c | 2381 | |
bae473a4 KS |
2382 | pte_unmap_unlock(fe->pte, fe->ptl); |
2383 | return wp_page_copy(fe, orig_pte, old_page); | |
251b97f5 | 2384 | } |
1da177e4 | 2385 | |
d08b3851 | 2386 | /* |
ee6a6457 PZ |
2387 | * Take out anonymous pages first, anonymous shared vmas are |
2388 | * not dirty accountable. | |
d08b3851 | 2389 | */ |
9a840895 | 2390 | if (PageAnon(old_page) && !PageKsm(old_page)) { |
6d0a07ed | 2391 | int total_mapcount; |
ab967d86 | 2392 | if (!trylock_page(old_page)) { |
09cbfeaf | 2393 | get_page(old_page); |
bae473a4 | 2394 | pte_unmap_unlock(fe->pte, fe->ptl); |
ab967d86 | 2395 | lock_page(old_page); |
bae473a4 KS |
2396 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, |
2397 | fe->address, &fe->ptl); | |
2398 | if (!pte_same(*fe->pte, orig_pte)) { | |
ab967d86 | 2399 | unlock_page(old_page); |
bae473a4 | 2400 | pte_unmap_unlock(fe->pte, fe->ptl); |
09cbfeaf | 2401 | put_page(old_page); |
28766805 | 2402 | return 0; |
ab967d86 | 2403 | } |
09cbfeaf | 2404 | put_page(old_page); |
ee6a6457 | 2405 | } |
6d0a07ed AA |
2406 | if (reuse_swap_page(old_page, &total_mapcount)) { |
2407 | if (total_mapcount == 1) { | |
2408 | /* | |
2409 | * The page is all ours. Move it to | |
2410 | * our anon_vma so the rmap code will | |
2411 | * not search our parent or siblings. | |
2412 | * Protected against the rmap code by | |
2413 | * the page lock. | |
2414 | */ | |
5a49973d | 2415 | page_move_anon_rmap(old_page, vma); |
6d0a07ed | 2416 | } |
b009c024 | 2417 | unlock_page(old_page); |
bae473a4 | 2418 | return wp_page_reuse(fe, orig_pte, old_page, 0, 0); |
b009c024 | 2419 | } |
ab967d86 | 2420 | unlock_page(old_page); |
ee6a6457 | 2421 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == |
d08b3851 | 2422 | (VM_WRITE|VM_SHARED))) { |
bae473a4 | 2423 | return wp_page_shared(fe, orig_pte, old_page); |
1da177e4 | 2424 | } |
1da177e4 LT |
2425 | |
2426 | /* | |
2427 | * Ok, we need to copy. Oh, well.. | |
2428 | */ | |
09cbfeaf | 2429 | get_page(old_page); |
28766805 | 2430 | |
bae473a4 KS |
2431 | pte_unmap_unlock(fe->pte, fe->ptl); |
2432 | return wp_page_copy(fe, orig_pte, old_page); | |
1da177e4 LT |
2433 | } |
2434 | ||
97a89413 | 2435 | static void unmap_mapping_range_vma(struct vm_area_struct *vma, |
1da177e4 LT |
2436 | unsigned long start_addr, unsigned long end_addr, |
2437 | struct zap_details *details) | |
2438 | { | |
f5cc4eef | 2439 | zap_page_range_single(vma, start_addr, end_addr - start_addr, details); |
1da177e4 LT |
2440 | } |
2441 | ||
6b2dbba8 | 2442 | static inline void unmap_mapping_range_tree(struct rb_root *root, |
1da177e4 LT |
2443 | struct zap_details *details) |
2444 | { | |
2445 | struct vm_area_struct *vma; | |
1da177e4 LT |
2446 | pgoff_t vba, vea, zba, zea; |
2447 | ||
6b2dbba8 | 2448 | vma_interval_tree_foreach(vma, root, |
1da177e4 | 2449 | details->first_index, details->last_index) { |
1da177e4 LT |
2450 | |
2451 | vba = vma->vm_pgoff; | |
d6e93217 | 2452 | vea = vba + vma_pages(vma) - 1; |
1da177e4 LT |
2453 | zba = details->first_index; |
2454 | if (zba < vba) | |
2455 | zba = vba; | |
2456 | zea = details->last_index; | |
2457 | if (zea > vea) | |
2458 | zea = vea; | |
2459 | ||
97a89413 | 2460 | unmap_mapping_range_vma(vma, |
1da177e4 LT |
2461 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, |
2462 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
97a89413 | 2463 | details); |
1da177e4 LT |
2464 | } |
2465 | } | |
2466 | ||
1da177e4 | 2467 | /** |
8a5f14a2 KS |
2468 | * unmap_mapping_range - unmap the portion of all mmaps in the specified |
2469 | * address_space corresponding to the specified page range in the underlying | |
2470 | * file. | |
2471 | * | |
3d41088f | 2472 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
2473 | * @holebegin: byte in first page to unmap, relative to the start of |
2474 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
25d9e2d1 | 2475 | * boundary. Note that this is different from truncate_pagecache(), which |
1da177e4 LT |
2476 | * must keep the partial page. In contrast, we must get rid of |
2477 | * partial pages. | |
2478 | * @holelen: size of prospective hole in bytes. This will be rounded | |
2479 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
2480 | * end of the file. | |
2481 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
2482 | * but 0 when invalidating pagecache, don't throw away private data. | |
2483 | */ | |
2484 | void unmap_mapping_range(struct address_space *mapping, | |
2485 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
2486 | { | |
aac45363 | 2487 | struct zap_details details = { }; |
1da177e4 LT |
2488 | pgoff_t hba = holebegin >> PAGE_SHIFT; |
2489 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2490 | ||
2491 | /* Check for overflow. */ | |
2492 | if (sizeof(holelen) > sizeof(hlen)) { | |
2493 | long long holeend = | |
2494 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2495 | if (holeend & ~(long long)ULONG_MAX) | |
2496 | hlen = ULONG_MAX - hba + 1; | |
2497 | } | |
2498 | ||
2499 | details.check_mapping = even_cows? NULL: mapping; | |
1da177e4 LT |
2500 | details.first_index = hba; |
2501 | details.last_index = hba + hlen - 1; | |
2502 | if (details.last_index < details.first_index) | |
2503 | details.last_index = ULONG_MAX; | |
1da177e4 | 2504 | |
46c043ed | 2505 | i_mmap_lock_write(mapping); |
6b2dbba8 | 2506 | if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap))) |
1da177e4 | 2507 | unmap_mapping_range_tree(&mapping->i_mmap, &details); |
46c043ed | 2508 | i_mmap_unlock_write(mapping); |
1da177e4 LT |
2509 | } |
2510 | EXPORT_SYMBOL(unmap_mapping_range); | |
2511 | ||
1da177e4 | 2512 | /* |
8f4e2101 HD |
2513 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2514 | * but allow concurrent faults), and pte mapped but not yet locked. | |
9a95f3cf PC |
2515 | * We return with pte unmapped and unlocked. |
2516 | * | |
2517 | * We return with the mmap_sem locked or unlocked in the same cases | |
2518 | * as does filemap_fault(). | |
1da177e4 | 2519 | */ |
bae473a4 | 2520 | int do_swap_page(struct fault_env *fe, pte_t orig_pte) |
1da177e4 | 2521 | { |
bae473a4 | 2522 | struct vm_area_struct *vma = fe->vma; |
56f31801 | 2523 | struct page *page, *swapcache; |
00501b53 | 2524 | struct mem_cgroup *memcg; |
65500d23 | 2525 | swp_entry_t entry; |
1da177e4 | 2526 | pte_t pte; |
d065bd81 | 2527 | int locked; |
ad8c2ee8 | 2528 | int exclusive = 0; |
83c54070 | 2529 | int ret = 0; |
1da177e4 | 2530 | |
bae473a4 | 2531 | if (!pte_unmap_same(vma->vm_mm, fe->pmd, fe->pte, orig_pte)) |
8f4e2101 | 2532 | goto out; |
65500d23 HD |
2533 | |
2534 | entry = pte_to_swp_entry(orig_pte); | |
d1737fdb AK |
2535 | if (unlikely(non_swap_entry(entry))) { |
2536 | if (is_migration_entry(entry)) { | |
bae473a4 | 2537 | migration_entry_wait(vma->vm_mm, fe->pmd, fe->address); |
d1737fdb AK |
2538 | } else if (is_hwpoison_entry(entry)) { |
2539 | ret = VM_FAULT_HWPOISON; | |
2540 | } else { | |
bae473a4 | 2541 | print_bad_pte(vma, fe->address, orig_pte, NULL); |
d99be1a8 | 2542 | ret = VM_FAULT_SIGBUS; |
d1737fdb | 2543 | } |
0697212a CL |
2544 | goto out; |
2545 | } | |
0ff92245 | 2546 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2547 | page = lookup_swap_cache(entry); |
2548 | if (!page) { | |
02098fea | 2549 | page = swapin_readahead(entry, |
bae473a4 | 2550 | GFP_HIGHUSER_MOVABLE, vma, fe->address); |
1da177e4 LT |
2551 | if (!page) { |
2552 | /* | |
8f4e2101 HD |
2553 | * Back out if somebody else faulted in this pte |
2554 | * while we released the pte lock. | |
1da177e4 | 2555 | */ |
bae473a4 KS |
2556 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, |
2557 | fe->address, &fe->ptl); | |
2558 | if (likely(pte_same(*fe->pte, orig_pte))) | |
1da177e4 | 2559 | ret = VM_FAULT_OOM; |
0ff92245 | 2560 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2561 | goto unlock; |
1da177e4 LT |
2562 | } |
2563 | ||
2564 | /* Had to read the page from swap area: Major fault */ | |
2565 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2566 | count_vm_event(PGMAJFAULT); |
bae473a4 | 2567 | mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); |
d1737fdb | 2568 | } else if (PageHWPoison(page)) { |
71f72525 WF |
2569 | /* |
2570 | * hwpoisoned dirty swapcache pages are kept for killing | |
2571 | * owner processes (which may be unknown at hwpoison time) | |
2572 | */ | |
d1737fdb AK |
2573 | ret = VM_FAULT_HWPOISON; |
2574 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); | |
56f31801 | 2575 | swapcache = page; |
4779cb31 | 2576 | goto out_release; |
1da177e4 LT |
2577 | } |
2578 | ||
56f31801 | 2579 | swapcache = page; |
bae473a4 | 2580 | locked = lock_page_or_retry(page, vma->vm_mm, fe->flags); |
e709ffd6 | 2581 | |
073e587e | 2582 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
d065bd81 ML |
2583 | if (!locked) { |
2584 | ret |= VM_FAULT_RETRY; | |
2585 | goto out_release; | |
2586 | } | |
073e587e | 2587 | |
4969c119 | 2588 | /* |
31c4a3d3 HD |
2589 | * Make sure try_to_free_swap or reuse_swap_page or swapoff did not |
2590 | * release the swapcache from under us. The page pin, and pte_same | |
2591 | * test below, are not enough to exclude that. Even if it is still | |
2592 | * swapcache, we need to check that the page's swap has not changed. | |
4969c119 | 2593 | */ |
31c4a3d3 | 2594 | if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val)) |
4969c119 AA |
2595 | goto out_page; |
2596 | ||
bae473a4 | 2597 | page = ksm_might_need_to_copy(page, vma, fe->address); |
cbf86cfe HD |
2598 | if (unlikely(!page)) { |
2599 | ret = VM_FAULT_OOM; | |
2600 | page = swapcache; | |
cbf86cfe | 2601 | goto out_page; |
5ad64688 HD |
2602 | } |
2603 | ||
bae473a4 KS |
2604 | if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, |
2605 | &memcg, false)) { | |
8a9f3ccd | 2606 | ret = VM_FAULT_OOM; |
bc43f75c | 2607 | goto out_page; |
8a9f3ccd BS |
2608 | } |
2609 | ||
1da177e4 | 2610 | /* |
8f4e2101 | 2611 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 2612 | */ |
bae473a4 KS |
2613 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address, |
2614 | &fe->ptl); | |
2615 | if (unlikely(!pte_same(*fe->pte, orig_pte))) | |
b8107480 | 2616 | goto out_nomap; |
b8107480 KK |
2617 | |
2618 | if (unlikely(!PageUptodate(page))) { | |
2619 | ret = VM_FAULT_SIGBUS; | |
2620 | goto out_nomap; | |
1da177e4 LT |
2621 | } |
2622 | ||
8c7c6e34 KH |
2623 | /* |
2624 | * The page isn't present yet, go ahead with the fault. | |
2625 | * | |
2626 | * Be careful about the sequence of operations here. | |
2627 | * To get its accounting right, reuse_swap_page() must be called | |
2628 | * while the page is counted on swap but not yet in mapcount i.e. | |
2629 | * before page_add_anon_rmap() and swap_free(); try_to_free_swap() | |
2630 | * must be called after the swap_free(), or it will never succeed. | |
8c7c6e34 | 2631 | */ |
1da177e4 | 2632 | |
bae473a4 KS |
2633 | inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); |
2634 | dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS); | |
1da177e4 | 2635 | pte = mk_pte(page, vma->vm_page_prot); |
bae473a4 | 2636 | if ((fe->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) { |
1da177e4 | 2637 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); |
bae473a4 | 2638 | fe->flags &= ~FAULT_FLAG_WRITE; |
9a5b489b | 2639 | ret |= VM_FAULT_WRITE; |
d281ee61 | 2640 | exclusive = RMAP_EXCLUSIVE; |
1da177e4 | 2641 | } |
1da177e4 | 2642 | flush_icache_page(vma, page); |
179ef71c CG |
2643 | if (pte_swp_soft_dirty(orig_pte)) |
2644 | pte = pte_mksoft_dirty(pte); | |
bae473a4 | 2645 | set_pte_at(vma->vm_mm, fe->address, fe->pte, pte); |
00501b53 | 2646 | if (page == swapcache) { |
bae473a4 | 2647 | do_page_add_anon_rmap(page, vma, fe->address, exclusive); |
f627c2f5 | 2648 | mem_cgroup_commit_charge(page, memcg, true, false); |
1a8018fb | 2649 | activate_page(page); |
00501b53 | 2650 | } else { /* ksm created a completely new copy */ |
bae473a4 | 2651 | page_add_new_anon_rmap(page, vma, fe->address, false); |
f627c2f5 | 2652 | mem_cgroup_commit_charge(page, memcg, false, false); |
00501b53 JW |
2653 | lru_cache_add_active_or_unevictable(page, vma); |
2654 | } | |
1da177e4 | 2655 | |
c475a8ab | 2656 | swap_free(entry); |
5ccc5aba VD |
2657 | if (mem_cgroup_swap_full(page) || |
2658 | (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) | |
a2c43eed | 2659 | try_to_free_swap(page); |
c475a8ab | 2660 | unlock_page(page); |
56f31801 | 2661 | if (page != swapcache) { |
4969c119 AA |
2662 | /* |
2663 | * Hold the lock to avoid the swap entry to be reused | |
2664 | * until we take the PT lock for the pte_same() check | |
2665 | * (to avoid false positives from pte_same). For | |
2666 | * further safety release the lock after the swap_free | |
2667 | * so that the swap count won't change under a | |
2668 | * parallel locked swapcache. | |
2669 | */ | |
2670 | unlock_page(swapcache); | |
09cbfeaf | 2671 | put_page(swapcache); |
4969c119 | 2672 | } |
c475a8ab | 2673 | |
bae473a4 KS |
2674 | if (fe->flags & FAULT_FLAG_WRITE) { |
2675 | ret |= do_wp_page(fe, pte); | |
61469f1d HD |
2676 | if (ret & VM_FAULT_ERROR) |
2677 | ret &= VM_FAULT_ERROR; | |
1da177e4 LT |
2678 | goto out; |
2679 | } | |
2680 | ||
2681 | /* No need to invalidate - it was non-present before */ | |
bae473a4 | 2682 | update_mmu_cache(vma, fe->address, fe->pte); |
65500d23 | 2683 | unlock: |
bae473a4 | 2684 | pte_unmap_unlock(fe->pte, fe->ptl); |
1da177e4 LT |
2685 | out: |
2686 | return ret; | |
b8107480 | 2687 | out_nomap: |
f627c2f5 | 2688 | mem_cgroup_cancel_charge(page, memcg, false); |
bae473a4 | 2689 | pte_unmap_unlock(fe->pte, fe->ptl); |
bc43f75c | 2690 | out_page: |
b8107480 | 2691 | unlock_page(page); |
4779cb31 | 2692 | out_release: |
09cbfeaf | 2693 | put_page(page); |
56f31801 | 2694 | if (page != swapcache) { |
4969c119 | 2695 | unlock_page(swapcache); |
09cbfeaf | 2696 | put_page(swapcache); |
4969c119 | 2697 | } |
65500d23 | 2698 | return ret; |
1da177e4 LT |
2699 | } |
2700 | ||
320b2b8d | 2701 | /* |
8ca3eb08 TL |
2702 | * This is like a special single-page "expand_{down|up}wards()", |
2703 | * except we must first make sure that 'address{-|+}PAGE_SIZE' | |
320b2b8d | 2704 | * doesn't hit another vma. |
320b2b8d LT |
2705 | */ |
2706 | static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address) | |
2707 | { | |
2708 | address &= PAGE_MASK; | |
2709 | if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) { | |
0e8e50e2 LT |
2710 | struct vm_area_struct *prev = vma->vm_prev; |
2711 | ||
2712 | /* | |
2713 | * Is there a mapping abutting this one below? | |
2714 | * | |
2715 | * That's only ok if it's the same stack mapping | |
2716 | * that has gotten split.. | |
2717 | */ | |
2718 | if (prev && prev->vm_end == address) | |
2719 | return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM; | |
320b2b8d | 2720 | |
fee7e49d | 2721 | return expand_downwards(vma, address - PAGE_SIZE); |
320b2b8d | 2722 | } |
8ca3eb08 TL |
2723 | if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) { |
2724 | struct vm_area_struct *next = vma->vm_next; | |
2725 | ||
2726 | /* As VM_GROWSDOWN but s/below/above/ */ | |
2727 | if (next && next->vm_start == address + PAGE_SIZE) | |
2728 | return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM; | |
2729 | ||
fee7e49d | 2730 | return expand_upwards(vma, address + PAGE_SIZE); |
8ca3eb08 | 2731 | } |
320b2b8d LT |
2732 | return 0; |
2733 | } | |
2734 | ||
1da177e4 | 2735 | /* |
8f4e2101 HD |
2736 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2737 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2738 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2739 | */ |
bae473a4 | 2740 | static int do_anonymous_page(struct fault_env *fe) |
1da177e4 | 2741 | { |
bae473a4 | 2742 | struct vm_area_struct *vma = fe->vma; |
00501b53 | 2743 | struct mem_cgroup *memcg; |
8f4e2101 | 2744 | struct page *page; |
1da177e4 | 2745 | pte_t entry; |
1da177e4 | 2746 | |
6b7339f4 KS |
2747 | /* File mapping without ->vm_ops ? */ |
2748 | if (vma->vm_flags & VM_SHARED) | |
2749 | return VM_FAULT_SIGBUS; | |
2750 | ||
11ac5524 | 2751 | /* Check if we need to add a guard page to the stack */ |
bae473a4 | 2752 | if (check_stack_guard_page(vma, fe->address) < 0) |
9c145c56 | 2753 | return VM_FAULT_SIGSEGV; |
320b2b8d | 2754 | |
7267ec00 KS |
2755 | /* |
2756 | * Use pte_alloc() instead of pte_alloc_map(). We can't run | |
2757 | * pte_offset_map() on pmds where a huge pmd might be created | |
2758 | * from a different thread. | |
2759 | * | |
2760 | * pte_alloc_map() is safe to use under down_write(mmap_sem) or when | |
2761 | * parallel threads are excluded by other means. | |
2762 | * | |
2763 | * Here we only have down_read(mmap_sem). | |
2764 | */ | |
2765 | if (pte_alloc(vma->vm_mm, fe->pmd, fe->address)) | |
2766 | return VM_FAULT_OOM; | |
2767 | ||
2768 | /* See the comment in pte_alloc_one_map() */ | |
2769 | if (unlikely(pmd_trans_unstable(fe->pmd))) | |
2770 | return 0; | |
2771 | ||
11ac5524 | 2772 | /* Use the zero-page for reads */ |
bae473a4 KS |
2773 | if (!(fe->flags & FAULT_FLAG_WRITE) && |
2774 | !mm_forbids_zeropage(vma->vm_mm)) { | |
2775 | entry = pte_mkspecial(pfn_pte(my_zero_pfn(fe->address), | |
62eede62 | 2776 | vma->vm_page_prot)); |
bae473a4 KS |
2777 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address, |
2778 | &fe->ptl); | |
2779 | if (!pte_none(*fe->pte)) | |
a13ea5b7 | 2780 | goto unlock; |
6b251fc9 AA |
2781 | /* Deliver the page fault to userland, check inside PT lock */ |
2782 | if (userfaultfd_missing(vma)) { | |
bae473a4 KS |
2783 | pte_unmap_unlock(fe->pte, fe->ptl); |
2784 | return handle_userfault(fe, VM_UFFD_MISSING); | |
6b251fc9 | 2785 | } |
a13ea5b7 HD |
2786 | goto setpte; |
2787 | } | |
2788 | ||
557ed1fa | 2789 | /* Allocate our own private page. */ |
557ed1fa NP |
2790 | if (unlikely(anon_vma_prepare(vma))) |
2791 | goto oom; | |
bae473a4 | 2792 | page = alloc_zeroed_user_highpage_movable(vma, fe->address); |
557ed1fa NP |
2793 | if (!page) |
2794 | goto oom; | |
eb3c24f3 | 2795 | |
bae473a4 | 2796 | if (mem_cgroup_try_charge(page, vma->vm_mm, GFP_KERNEL, &memcg, false)) |
eb3c24f3 MG |
2797 | goto oom_free_page; |
2798 | ||
52f37629 MK |
2799 | /* |
2800 | * The memory barrier inside __SetPageUptodate makes sure that | |
2801 | * preceeding stores to the page contents become visible before | |
2802 | * the set_pte_at() write. | |
2803 | */ | |
0ed361de | 2804 | __SetPageUptodate(page); |
8f4e2101 | 2805 | |
557ed1fa | 2806 | entry = mk_pte(page, vma->vm_page_prot); |
1ac0cb5d HD |
2807 | if (vma->vm_flags & VM_WRITE) |
2808 | entry = pte_mkwrite(pte_mkdirty(entry)); | |
1da177e4 | 2809 | |
bae473a4 KS |
2810 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address, |
2811 | &fe->ptl); | |
2812 | if (!pte_none(*fe->pte)) | |
557ed1fa | 2813 | goto release; |
9ba69294 | 2814 | |
6b251fc9 AA |
2815 | /* Deliver the page fault to userland, check inside PT lock */ |
2816 | if (userfaultfd_missing(vma)) { | |
bae473a4 | 2817 | pte_unmap_unlock(fe->pte, fe->ptl); |
f627c2f5 | 2818 | mem_cgroup_cancel_charge(page, memcg, false); |
09cbfeaf | 2819 | put_page(page); |
bae473a4 | 2820 | return handle_userfault(fe, VM_UFFD_MISSING); |
6b251fc9 AA |
2821 | } |
2822 | ||
bae473a4 KS |
2823 | inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); |
2824 | page_add_new_anon_rmap(page, vma, fe->address, false); | |
f627c2f5 | 2825 | mem_cgroup_commit_charge(page, memcg, false, false); |
00501b53 | 2826 | lru_cache_add_active_or_unevictable(page, vma); |
a13ea5b7 | 2827 | setpte: |
bae473a4 | 2828 | set_pte_at(vma->vm_mm, fe->address, fe->pte, entry); |
1da177e4 LT |
2829 | |
2830 | /* No need to invalidate - it was non-present before */ | |
bae473a4 | 2831 | update_mmu_cache(vma, fe->address, fe->pte); |
65500d23 | 2832 | unlock: |
bae473a4 | 2833 | pte_unmap_unlock(fe->pte, fe->ptl); |
83c54070 | 2834 | return 0; |
8f4e2101 | 2835 | release: |
f627c2f5 | 2836 | mem_cgroup_cancel_charge(page, memcg, false); |
09cbfeaf | 2837 | put_page(page); |
8f4e2101 | 2838 | goto unlock; |
8a9f3ccd | 2839 | oom_free_page: |
09cbfeaf | 2840 | put_page(page); |
65500d23 | 2841 | oom: |
1da177e4 LT |
2842 | return VM_FAULT_OOM; |
2843 | } | |
2844 | ||
9a95f3cf PC |
2845 | /* |
2846 | * The mmap_sem must have been held on entry, and may have been | |
2847 | * released depending on flags and vma->vm_ops->fault() return value. | |
2848 | * See filemap_fault() and __lock_page_retry(). | |
2849 | */ | |
bae473a4 KS |
2850 | static int __do_fault(struct fault_env *fe, pgoff_t pgoff, |
2851 | struct page *cow_page, struct page **page, void **entry) | |
7eae74af | 2852 | { |
bae473a4 | 2853 | struct vm_area_struct *vma = fe->vma; |
7eae74af KS |
2854 | struct vm_fault vmf; |
2855 | int ret; | |
2856 | ||
bae473a4 | 2857 | vmf.virtual_address = (void __user *)(fe->address & PAGE_MASK); |
7eae74af | 2858 | vmf.pgoff = pgoff; |
bae473a4 | 2859 | vmf.flags = fe->flags; |
7eae74af | 2860 | vmf.page = NULL; |
c20cd45e | 2861 | vmf.gfp_mask = __get_fault_gfp_mask(vma); |
2e4cdab0 | 2862 | vmf.cow_page = cow_page; |
7eae74af KS |
2863 | |
2864 | ret = vma->vm_ops->fault(vma, &vmf); | |
2865 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) | |
2866 | return ret; | |
bc2466e4 JK |
2867 | if (ret & VM_FAULT_DAX_LOCKED) { |
2868 | *entry = vmf.entry; | |
2869 | return ret; | |
2870 | } | |
7eae74af KS |
2871 | |
2872 | if (unlikely(PageHWPoison(vmf.page))) { | |
2873 | if (ret & VM_FAULT_LOCKED) | |
2874 | unlock_page(vmf.page); | |
09cbfeaf | 2875 | put_page(vmf.page); |
7eae74af KS |
2876 | return VM_FAULT_HWPOISON; |
2877 | } | |
2878 | ||
2879 | if (unlikely(!(ret & VM_FAULT_LOCKED))) | |
2880 | lock_page(vmf.page); | |
2881 | else | |
2882 | VM_BUG_ON_PAGE(!PageLocked(vmf.page), vmf.page); | |
2883 | ||
2884 | *page = vmf.page; | |
2885 | return ret; | |
2886 | } | |
2887 | ||
7267ec00 KS |
2888 | static int pte_alloc_one_map(struct fault_env *fe) |
2889 | { | |
2890 | struct vm_area_struct *vma = fe->vma; | |
2891 | ||
2892 | if (!pmd_none(*fe->pmd)) | |
2893 | goto map_pte; | |
2894 | if (fe->prealloc_pte) { | |
2895 | fe->ptl = pmd_lock(vma->vm_mm, fe->pmd); | |
2896 | if (unlikely(!pmd_none(*fe->pmd))) { | |
2897 | spin_unlock(fe->ptl); | |
2898 | goto map_pte; | |
2899 | } | |
2900 | ||
2901 | atomic_long_inc(&vma->vm_mm->nr_ptes); | |
2902 | pmd_populate(vma->vm_mm, fe->pmd, fe->prealloc_pte); | |
2903 | spin_unlock(fe->ptl); | |
2904 | fe->prealloc_pte = 0; | |
2905 | } else if (unlikely(pte_alloc(vma->vm_mm, fe->pmd, fe->address))) { | |
2906 | return VM_FAULT_OOM; | |
2907 | } | |
2908 | map_pte: | |
2909 | /* | |
2910 | * If a huge pmd materialized under us just retry later. Use | |
2911 | * pmd_trans_unstable() instead of pmd_trans_huge() to ensure the pmd | |
2912 | * didn't become pmd_trans_huge under us and then back to pmd_none, as | |
2913 | * a result of MADV_DONTNEED running immediately after a huge pmd fault | |
2914 | * in a different thread of this mm, in turn leading to a misleading | |
2915 | * pmd_trans_huge() retval. All we have to ensure is that it is a | |
2916 | * regular pmd that we can walk with pte_offset_map() and we can do that | |
2917 | * through an atomic read in C, which is what pmd_trans_unstable() | |
2918 | * provides. | |
2919 | */ | |
2920 | if (pmd_trans_unstable(fe->pmd) || pmd_devmap(*fe->pmd)) | |
2921 | return VM_FAULT_NOPAGE; | |
2922 | ||
2923 | fe->pte = pte_offset_map_lock(vma->vm_mm, fe->pmd, fe->address, | |
2924 | &fe->ptl); | |
2925 | return 0; | |
2926 | } | |
2927 | ||
e496cf3d | 2928 | #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE |
10102459 KS |
2929 | |
2930 | #define HPAGE_CACHE_INDEX_MASK (HPAGE_PMD_NR - 1) | |
2931 | static inline bool transhuge_vma_suitable(struct vm_area_struct *vma, | |
2932 | unsigned long haddr) | |
2933 | { | |
2934 | if (((vma->vm_start >> PAGE_SHIFT) & HPAGE_CACHE_INDEX_MASK) != | |
2935 | (vma->vm_pgoff & HPAGE_CACHE_INDEX_MASK)) | |
2936 | return false; | |
2937 | if (haddr < vma->vm_start || haddr + HPAGE_PMD_SIZE > vma->vm_end) | |
2938 | return false; | |
2939 | return true; | |
2940 | } | |
2941 | ||
2942 | static int do_set_pmd(struct fault_env *fe, struct page *page) | |
2943 | { | |
2944 | struct vm_area_struct *vma = fe->vma; | |
2945 | bool write = fe->flags & FAULT_FLAG_WRITE; | |
2946 | unsigned long haddr = fe->address & HPAGE_PMD_MASK; | |
2947 | pmd_t entry; | |
2948 | int i, ret; | |
2949 | ||
2950 | if (!transhuge_vma_suitable(vma, haddr)) | |
2951 | return VM_FAULT_FALLBACK; | |
2952 | ||
2953 | ret = VM_FAULT_FALLBACK; | |
2954 | page = compound_head(page); | |
2955 | ||
2956 | fe->ptl = pmd_lock(vma->vm_mm, fe->pmd); | |
2957 | if (unlikely(!pmd_none(*fe->pmd))) | |
2958 | goto out; | |
2959 | ||
2960 | for (i = 0; i < HPAGE_PMD_NR; i++) | |
2961 | flush_icache_page(vma, page + i); | |
2962 | ||
2963 | entry = mk_huge_pmd(page, vma->vm_page_prot); | |
2964 | if (write) | |
2965 | entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); | |
2966 | ||
2967 | add_mm_counter(vma->vm_mm, MM_FILEPAGES, HPAGE_PMD_NR); | |
2968 | page_add_file_rmap(page, true); | |
2969 | ||
2970 | set_pmd_at(vma->vm_mm, haddr, fe->pmd, entry); | |
2971 | ||
2972 | update_mmu_cache_pmd(vma, haddr, fe->pmd); | |
2973 | ||
2974 | /* fault is handled */ | |
2975 | ret = 0; | |
95ecedcd | 2976 | count_vm_event(THP_FILE_MAPPED); |
10102459 KS |
2977 | out: |
2978 | spin_unlock(fe->ptl); | |
2979 | return ret; | |
2980 | } | |
2981 | #else | |
2982 | static int do_set_pmd(struct fault_env *fe, struct page *page) | |
2983 | { | |
2984 | BUILD_BUG(); | |
2985 | return 0; | |
2986 | } | |
2987 | #endif | |
2988 | ||
8c6e50b0 | 2989 | /** |
7267ec00 KS |
2990 | * alloc_set_pte - setup new PTE entry for given page and add reverse page |
2991 | * mapping. If needed, the fucntion allocates page table or use pre-allocated. | |
8c6e50b0 | 2992 | * |
bae473a4 | 2993 | * @fe: fault environment |
7267ec00 | 2994 | * @memcg: memcg to charge page (only for private mappings) |
8c6e50b0 | 2995 | * @page: page to map |
8c6e50b0 | 2996 | * |
7267ec00 | 2997 | * Caller must take care of unlocking fe->ptl, if fe->pte is non-NULL on return. |
8c6e50b0 KS |
2998 | * |
2999 | * Target users are page handler itself and implementations of | |
3000 | * vm_ops->map_pages. | |
3001 | */ | |
7267ec00 KS |
3002 | int alloc_set_pte(struct fault_env *fe, struct mem_cgroup *memcg, |
3003 | struct page *page) | |
3bb97794 | 3004 | { |
bae473a4 KS |
3005 | struct vm_area_struct *vma = fe->vma; |
3006 | bool write = fe->flags & FAULT_FLAG_WRITE; | |
3bb97794 | 3007 | pte_t entry; |
10102459 KS |
3008 | int ret; |
3009 | ||
e496cf3d KS |
3010 | if (pmd_none(*fe->pmd) && PageTransCompound(page) && |
3011 | IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) { | |
10102459 KS |
3012 | /* THP on COW? */ |
3013 | VM_BUG_ON_PAGE(memcg, page); | |
3014 | ||
3015 | ret = do_set_pmd(fe, page); | |
3016 | if (ret != VM_FAULT_FALLBACK) | |
3017 | return ret; | |
3018 | } | |
3bb97794 | 3019 | |
7267ec00 | 3020 | if (!fe->pte) { |
10102459 | 3021 | ret = pte_alloc_one_map(fe); |
7267ec00 KS |
3022 | if (ret) |
3023 | return ret; | |
3024 | } | |
3025 | ||
3026 | /* Re-check under ptl */ | |
3027 | if (unlikely(!pte_none(*fe->pte))) | |
3028 | return VM_FAULT_NOPAGE; | |
3029 | ||
3bb97794 KS |
3030 | flush_icache_page(vma, page); |
3031 | entry = mk_pte(page, vma->vm_page_prot); | |
3032 | if (write) | |
3033 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
bae473a4 KS |
3034 | /* copy-on-write page */ |
3035 | if (write && !(vma->vm_flags & VM_SHARED)) { | |
3bb97794 | 3036 | inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES); |
bae473a4 | 3037 | page_add_new_anon_rmap(page, vma, fe->address, false); |
7267ec00 KS |
3038 | mem_cgroup_commit_charge(page, memcg, false, false); |
3039 | lru_cache_add_active_or_unevictable(page, vma); | |
3bb97794 | 3040 | } else { |
eca56ff9 | 3041 | inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); |
dd78fedd | 3042 | page_add_file_rmap(page, false); |
3bb97794 | 3043 | } |
bae473a4 | 3044 | set_pte_at(vma->vm_mm, fe->address, fe->pte, entry); |
3bb97794 KS |
3045 | |
3046 | /* no need to invalidate: a not-present page won't be cached */ | |
bae473a4 | 3047 | update_mmu_cache(vma, fe->address, fe->pte); |
7267ec00 KS |
3048 | |
3049 | return 0; | |
3bb97794 KS |
3050 | } |
3051 | ||
3a91053a KS |
3052 | static unsigned long fault_around_bytes __read_mostly = |
3053 | rounddown_pow_of_two(65536); | |
a9b0f861 | 3054 | |
a9b0f861 KS |
3055 | #ifdef CONFIG_DEBUG_FS |
3056 | static int fault_around_bytes_get(void *data, u64 *val) | |
1592eef0 | 3057 | { |
a9b0f861 | 3058 | *val = fault_around_bytes; |
1592eef0 KS |
3059 | return 0; |
3060 | } | |
3061 | ||
b4903d6e AR |
3062 | /* |
3063 | * fault_around_pages() and fault_around_mask() expects fault_around_bytes | |
3064 | * rounded down to nearest page order. It's what do_fault_around() expects to | |
3065 | * see. | |
3066 | */ | |
a9b0f861 | 3067 | static int fault_around_bytes_set(void *data, u64 val) |
1592eef0 | 3068 | { |
a9b0f861 | 3069 | if (val / PAGE_SIZE > PTRS_PER_PTE) |
1592eef0 | 3070 | return -EINVAL; |
b4903d6e AR |
3071 | if (val > PAGE_SIZE) |
3072 | fault_around_bytes = rounddown_pow_of_two(val); | |
3073 | else | |
3074 | fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */ | |
1592eef0 KS |
3075 | return 0; |
3076 | } | |
a9b0f861 KS |
3077 | DEFINE_SIMPLE_ATTRIBUTE(fault_around_bytes_fops, |
3078 | fault_around_bytes_get, fault_around_bytes_set, "%llu\n"); | |
1592eef0 KS |
3079 | |
3080 | static int __init fault_around_debugfs(void) | |
3081 | { | |
3082 | void *ret; | |
3083 | ||
a9b0f861 KS |
3084 | ret = debugfs_create_file("fault_around_bytes", 0644, NULL, NULL, |
3085 | &fault_around_bytes_fops); | |
1592eef0 | 3086 | if (!ret) |
a9b0f861 | 3087 | pr_warn("Failed to create fault_around_bytes in debugfs"); |
1592eef0 KS |
3088 | return 0; |
3089 | } | |
3090 | late_initcall(fault_around_debugfs); | |
1592eef0 | 3091 | #endif |
8c6e50b0 | 3092 | |
1fdb412b KS |
3093 | /* |
3094 | * do_fault_around() tries to map few pages around the fault address. The hope | |
3095 | * is that the pages will be needed soon and this will lower the number of | |
3096 | * faults to handle. | |
3097 | * | |
3098 | * It uses vm_ops->map_pages() to map the pages, which skips the page if it's | |
3099 | * not ready to be mapped: not up-to-date, locked, etc. | |
3100 | * | |
3101 | * This function is called with the page table lock taken. In the split ptlock | |
3102 | * case the page table lock only protects only those entries which belong to | |
3103 | * the page table corresponding to the fault address. | |
3104 | * | |
3105 | * This function doesn't cross the VMA boundaries, in order to call map_pages() | |
3106 | * only once. | |
3107 | * | |
3108 | * fault_around_pages() defines how many pages we'll try to map. | |
3109 | * do_fault_around() expects it to return a power of two less than or equal to | |
3110 | * PTRS_PER_PTE. | |
3111 | * | |
3112 | * The virtual address of the area that we map is naturally aligned to the | |
3113 | * fault_around_pages() value (and therefore to page order). This way it's | |
3114 | * easier to guarantee that we don't cross page table boundaries. | |
3115 | */ | |
7267ec00 | 3116 | static int do_fault_around(struct fault_env *fe, pgoff_t start_pgoff) |
8c6e50b0 | 3117 | { |
7267ec00 | 3118 | unsigned long address = fe->address, nr_pages, mask; |
bae473a4 | 3119 | pgoff_t end_pgoff; |
7267ec00 | 3120 | int off, ret = 0; |
8c6e50b0 | 3121 | |
4db0c3c2 | 3122 | nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT; |
aecd6f44 KS |
3123 | mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK; |
3124 | ||
7267ec00 KS |
3125 | fe->address = max(address & mask, fe->vma->vm_start); |
3126 | off = ((address - fe->address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); | |
bae473a4 | 3127 | start_pgoff -= off; |
8c6e50b0 KS |
3128 | |
3129 | /* | |
bae473a4 KS |
3130 | * end_pgoff is either end of page table or end of vma |
3131 | * or fault_around_pages() from start_pgoff, depending what is nearest. | |
8c6e50b0 | 3132 | */ |
bae473a4 | 3133 | end_pgoff = start_pgoff - |
7267ec00 | 3134 | ((fe->address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) + |
8c6e50b0 | 3135 | PTRS_PER_PTE - 1; |
bae473a4 KS |
3136 | end_pgoff = min3(end_pgoff, vma_pages(fe->vma) + fe->vma->vm_pgoff - 1, |
3137 | start_pgoff + nr_pages - 1); | |
8c6e50b0 | 3138 | |
7267ec00 KS |
3139 | if (pmd_none(*fe->pmd)) { |
3140 | fe->prealloc_pte = pte_alloc_one(fe->vma->vm_mm, fe->address); | |
c5f88bd2 VN |
3141 | if (!fe->prealloc_pte) |
3142 | goto out; | |
7267ec00 | 3143 | smp_wmb(); /* See comment in __pte_alloc() */ |
8c6e50b0 KS |
3144 | } |
3145 | ||
bae473a4 | 3146 | fe->vma->vm_ops->map_pages(fe, start_pgoff, end_pgoff); |
7267ec00 KS |
3147 | |
3148 | /* preallocated pagetable is unused: free it */ | |
3149 | if (fe->prealloc_pte) { | |
3150 | pte_free(fe->vma->vm_mm, fe->prealloc_pte); | |
3151 | fe->prealloc_pte = 0; | |
3152 | } | |
3153 | /* Huge page is mapped? Page fault is solved */ | |
3154 | if (pmd_trans_huge(*fe->pmd)) { | |
3155 | ret = VM_FAULT_NOPAGE; | |
3156 | goto out; | |
3157 | } | |
3158 | ||
3159 | /* ->map_pages() haven't done anything useful. Cold page cache? */ | |
3160 | if (!fe->pte) | |
3161 | goto out; | |
3162 | ||
3163 | /* check if the page fault is solved */ | |
3164 | fe->pte -= (fe->address >> PAGE_SHIFT) - (address >> PAGE_SHIFT); | |
3165 | if (!pte_none(*fe->pte)) | |
3166 | ret = VM_FAULT_NOPAGE; | |
3167 | pte_unmap_unlock(fe->pte, fe->ptl); | |
bae473a4 | 3168 | out: |
bae473a4 | 3169 | fe->address = address; |
7267ec00 KS |
3170 | fe->pte = NULL; |
3171 | return ret; | |
8c6e50b0 KS |
3172 | } |
3173 | ||
7267ec00 | 3174 | static int do_read_fault(struct fault_env *fe, pgoff_t pgoff) |
e655fb29 | 3175 | { |
bae473a4 | 3176 | struct vm_area_struct *vma = fe->vma; |
e655fb29 | 3177 | struct page *fault_page; |
8c6e50b0 KS |
3178 | int ret = 0; |
3179 | ||
3180 | /* | |
3181 | * Let's call ->map_pages() first and use ->fault() as fallback | |
3182 | * if page by the offset is not ready to be mapped (cold cache or | |
3183 | * something). | |
3184 | */ | |
9b4bdd2f | 3185 | if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) { |
7267ec00 KS |
3186 | ret = do_fault_around(fe, pgoff); |
3187 | if (ret) | |
3188 | return ret; | |
8c6e50b0 | 3189 | } |
e655fb29 | 3190 | |
bae473a4 | 3191 | ret = __do_fault(fe, pgoff, NULL, &fault_page, NULL); |
e655fb29 KS |
3192 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) |
3193 | return ret; | |
3194 | ||
7267ec00 KS |
3195 | ret |= alloc_set_pte(fe, NULL, fault_page); |
3196 | if (fe->pte) | |
bae473a4 | 3197 | pte_unmap_unlock(fe->pte, fe->ptl); |
e655fb29 | 3198 | unlock_page(fault_page); |
7267ec00 KS |
3199 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) |
3200 | put_page(fault_page); | |
e655fb29 KS |
3201 | return ret; |
3202 | } | |
3203 | ||
7267ec00 | 3204 | static int do_cow_fault(struct fault_env *fe, pgoff_t pgoff) |
ec47c3b9 | 3205 | { |
bae473a4 | 3206 | struct vm_area_struct *vma = fe->vma; |
ec47c3b9 | 3207 | struct page *fault_page, *new_page; |
bc2466e4 | 3208 | void *fault_entry; |
00501b53 | 3209 | struct mem_cgroup *memcg; |
ec47c3b9 KS |
3210 | int ret; |
3211 | ||
3212 | if (unlikely(anon_vma_prepare(vma))) | |
3213 | return VM_FAULT_OOM; | |
3214 | ||
bae473a4 | 3215 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, fe->address); |
ec47c3b9 KS |
3216 | if (!new_page) |
3217 | return VM_FAULT_OOM; | |
3218 | ||
bae473a4 KS |
3219 | if (mem_cgroup_try_charge(new_page, vma->vm_mm, GFP_KERNEL, |
3220 | &memcg, false)) { | |
09cbfeaf | 3221 | put_page(new_page); |
ec47c3b9 KS |
3222 | return VM_FAULT_OOM; |
3223 | } | |
3224 | ||
bae473a4 | 3225 | ret = __do_fault(fe, pgoff, new_page, &fault_page, &fault_entry); |
ec47c3b9 KS |
3226 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) |
3227 | goto uncharge_out; | |
3228 | ||
bc2466e4 | 3229 | if (!(ret & VM_FAULT_DAX_LOCKED)) |
bae473a4 | 3230 | copy_user_highpage(new_page, fault_page, fe->address, vma); |
ec47c3b9 KS |
3231 | __SetPageUptodate(new_page); |
3232 | ||
7267ec00 KS |
3233 | ret |= alloc_set_pte(fe, memcg, new_page); |
3234 | if (fe->pte) | |
bae473a4 | 3235 | pte_unmap_unlock(fe->pte, fe->ptl); |
bc2466e4 | 3236 | if (!(ret & VM_FAULT_DAX_LOCKED)) { |
2e4cdab0 | 3237 | unlock_page(fault_page); |
09cbfeaf | 3238 | put_page(fault_page); |
2e4cdab0 | 3239 | } else { |
bc2466e4 | 3240 | dax_unlock_mapping_entry(vma->vm_file->f_mapping, pgoff); |
2e4cdab0 | 3241 | } |
7267ec00 KS |
3242 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) |
3243 | goto uncharge_out; | |
ec47c3b9 KS |
3244 | return ret; |
3245 | uncharge_out: | |
f627c2f5 | 3246 | mem_cgroup_cancel_charge(new_page, memcg, false); |
09cbfeaf | 3247 | put_page(new_page); |
ec47c3b9 KS |
3248 | return ret; |
3249 | } | |
3250 | ||
7267ec00 | 3251 | static int do_shared_fault(struct fault_env *fe, pgoff_t pgoff) |
1da177e4 | 3252 | { |
bae473a4 | 3253 | struct vm_area_struct *vma = fe->vma; |
f0c6d4d2 KS |
3254 | struct page *fault_page; |
3255 | struct address_space *mapping; | |
f0c6d4d2 | 3256 | int dirtied = 0; |
f0c6d4d2 | 3257 | int ret, tmp; |
1d65f86d | 3258 | |
bae473a4 | 3259 | ret = __do_fault(fe, pgoff, NULL, &fault_page, NULL); |
7eae74af | 3260 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY))) |
f0c6d4d2 | 3261 | return ret; |
1da177e4 LT |
3262 | |
3263 | /* | |
f0c6d4d2 KS |
3264 | * Check if the backing address space wants to know that the page is |
3265 | * about to become writable | |
1da177e4 | 3266 | */ |
fb09a464 KS |
3267 | if (vma->vm_ops->page_mkwrite) { |
3268 | unlock_page(fault_page); | |
bae473a4 | 3269 | tmp = do_page_mkwrite(vma, fault_page, fe->address); |
fb09a464 KS |
3270 | if (unlikely(!tmp || |
3271 | (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) { | |
09cbfeaf | 3272 | put_page(fault_page); |
fb09a464 | 3273 | return tmp; |
4294621f | 3274 | } |
fb09a464 KS |
3275 | } |
3276 | ||
7267ec00 KS |
3277 | ret |= alloc_set_pte(fe, NULL, fault_page); |
3278 | if (fe->pte) | |
bae473a4 | 3279 | pte_unmap_unlock(fe->pte, fe->ptl); |
7267ec00 KS |
3280 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | |
3281 | VM_FAULT_RETRY))) { | |
f0c6d4d2 | 3282 | unlock_page(fault_page); |
09cbfeaf | 3283 | put_page(fault_page); |
f0c6d4d2 | 3284 | return ret; |
1da177e4 | 3285 | } |
b827e496 | 3286 | |
f0c6d4d2 KS |
3287 | if (set_page_dirty(fault_page)) |
3288 | dirtied = 1; | |
d82fa87d AM |
3289 | /* |
3290 | * Take a local copy of the address_space - page.mapping may be zeroed | |
3291 | * by truncate after unlock_page(). The address_space itself remains | |
3292 | * pinned by vma->vm_file's reference. We rely on unlock_page()'s | |
3293 | * release semantics to prevent the compiler from undoing this copying. | |
3294 | */ | |
1c290f64 | 3295 | mapping = page_rmapping(fault_page); |
f0c6d4d2 KS |
3296 | unlock_page(fault_page); |
3297 | if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) { | |
3298 | /* | |
3299 | * Some device drivers do not set page.mapping but still | |
3300 | * dirty their pages | |
3301 | */ | |
3302 | balance_dirty_pages_ratelimited(mapping); | |
d08b3851 | 3303 | } |
d00806b1 | 3304 | |
74ec6751 | 3305 | if (!vma->vm_ops->page_mkwrite) |
f0c6d4d2 | 3306 | file_update_time(vma->vm_file); |
b827e496 | 3307 | |
1d65f86d | 3308 | return ret; |
54cb8821 | 3309 | } |
d00806b1 | 3310 | |
9a95f3cf PC |
3311 | /* |
3312 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
3313 | * but allow concurrent faults). | |
3314 | * The mmap_sem may have been released depending on flags and our | |
3315 | * return value. See filemap_fault() and __lock_page_or_retry(). | |
3316 | */ | |
7267ec00 | 3317 | static int do_fault(struct fault_env *fe) |
54cb8821 | 3318 | { |
bae473a4 KS |
3319 | struct vm_area_struct *vma = fe->vma; |
3320 | pgoff_t pgoff = linear_page_index(vma, fe->address); | |
54cb8821 | 3321 | |
6b7339f4 KS |
3322 | /* The VMA was not fully populated on mmap() or missing VM_DONTEXPAND */ |
3323 | if (!vma->vm_ops->fault) | |
3324 | return VM_FAULT_SIGBUS; | |
bae473a4 | 3325 | if (!(fe->flags & FAULT_FLAG_WRITE)) |
7267ec00 | 3326 | return do_read_fault(fe, pgoff); |
ec47c3b9 | 3327 | if (!(vma->vm_flags & VM_SHARED)) |
7267ec00 KS |
3328 | return do_cow_fault(fe, pgoff); |
3329 | return do_shared_fault(fe, pgoff); | |
54cb8821 NP |
3330 | } |
3331 | ||
b19a9939 | 3332 | static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma, |
04bb2f94 RR |
3333 | unsigned long addr, int page_nid, |
3334 | int *flags) | |
9532fec1 MG |
3335 | { |
3336 | get_page(page); | |
3337 | ||
3338 | count_vm_numa_event(NUMA_HINT_FAULTS); | |
04bb2f94 | 3339 | if (page_nid == numa_node_id()) { |
9532fec1 | 3340 | count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL); |
04bb2f94 RR |
3341 | *flags |= TNF_FAULT_LOCAL; |
3342 | } | |
9532fec1 MG |
3343 | |
3344 | return mpol_misplaced(page, vma, addr); | |
3345 | } | |
3346 | ||
bae473a4 | 3347 | static int do_numa_page(struct fault_env *fe, pte_t pte) |
d10e63f2 | 3348 | { |
bae473a4 | 3349 | struct vm_area_struct *vma = fe->vma; |
4daae3b4 | 3350 | struct page *page = NULL; |
8191acbd | 3351 | int page_nid = -1; |
90572890 | 3352 | int last_cpupid; |
cbee9f88 | 3353 | int target_nid; |
b8593bfd | 3354 | bool migrated = false; |
b191f9b1 | 3355 | bool was_writable = pte_write(pte); |
6688cc05 | 3356 | int flags = 0; |
d10e63f2 MG |
3357 | |
3358 | /* | |
3359 | * The "pte" at this point cannot be used safely without | |
3360 | * validation through pte_unmap_same(). It's of NUMA type but | |
3361 | * the pfn may be screwed if the read is non atomic. | |
3362 | * | |
4d942466 MG |
3363 | * We can safely just do a "set_pte_at()", because the old |
3364 | * page table entry is not accessible, so there would be no | |
3365 | * concurrent hardware modifications to the PTE. | |
d10e63f2 | 3366 | */ |
bae473a4 KS |
3367 | fe->ptl = pte_lockptr(vma->vm_mm, fe->pmd); |
3368 | spin_lock(fe->ptl); | |
3369 | if (unlikely(!pte_same(*fe->pte, pte))) { | |
3370 | pte_unmap_unlock(fe->pte, fe->ptl); | |
4daae3b4 MG |
3371 | goto out; |
3372 | } | |
3373 | ||
4d942466 MG |
3374 | /* Make it present again */ |
3375 | pte = pte_modify(pte, vma->vm_page_prot); | |
3376 | pte = pte_mkyoung(pte); | |
b191f9b1 MG |
3377 | if (was_writable) |
3378 | pte = pte_mkwrite(pte); | |
bae473a4 KS |
3379 | set_pte_at(vma->vm_mm, fe->address, fe->pte, pte); |
3380 | update_mmu_cache(vma, fe->address, fe->pte); | |
d10e63f2 | 3381 | |
bae473a4 | 3382 | page = vm_normal_page(vma, fe->address, pte); |
d10e63f2 | 3383 | if (!page) { |
bae473a4 | 3384 | pte_unmap_unlock(fe->pte, fe->ptl); |
d10e63f2 MG |
3385 | return 0; |
3386 | } | |
3387 | ||
e81c4802 KS |
3388 | /* TODO: handle PTE-mapped THP */ |
3389 | if (PageCompound(page)) { | |
bae473a4 | 3390 | pte_unmap_unlock(fe->pte, fe->ptl); |
e81c4802 KS |
3391 | return 0; |
3392 | } | |
3393 | ||
6688cc05 | 3394 | /* |
bea66fbd MG |
3395 | * Avoid grouping on RO pages in general. RO pages shouldn't hurt as |
3396 | * much anyway since they can be in shared cache state. This misses | |
3397 | * the case where a mapping is writable but the process never writes | |
3398 | * to it but pte_write gets cleared during protection updates and | |
3399 | * pte_dirty has unpredictable behaviour between PTE scan updates, | |
3400 | * background writeback, dirty balancing and application behaviour. | |
6688cc05 | 3401 | */ |
d59dc7bc | 3402 | if (!pte_write(pte)) |
6688cc05 PZ |
3403 | flags |= TNF_NO_GROUP; |
3404 | ||
dabe1d99 RR |
3405 | /* |
3406 | * Flag if the page is shared between multiple address spaces. This | |
3407 | * is later used when determining whether to group tasks together | |
3408 | */ | |
3409 | if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED)) | |
3410 | flags |= TNF_SHARED; | |
3411 | ||
90572890 | 3412 | last_cpupid = page_cpupid_last(page); |
8191acbd | 3413 | page_nid = page_to_nid(page); |
bae473a4 KS |
3414 | target_nid = numa_migrate_prep(page, vma, fe->address, page_nid, |
3415 | &flags); | |
3416 | pte_unmap_unlock(fe->pte, fe->ptl); | |
4daae3b4 | 3417 | if (target_nid == -1) { |
4daae3b4 MG |
3418 | put_page(page); |
3419 | goto out; | |
3420 | } | |
3421 | ||
3422 | /* Migrate to the requested node */ | |
1bc115d8 | 3423 | migrated = migrate_misplaced_page(page, vma, target_nid); |
6688cc05 | 3424 | if (migrated) { |
8191acbd | 3425 | page_nid = target_nid; |
6688cc05 | 3426 | flags |= TNF_MIGRATED; |
074c2381 MG |
3427 | } else |
3428 | flags |= TNF_MIGRATE_FAIL; | |
4daae3b4 MG |
3429 | |
3430 | out: | |
8191acbd | 3431 | if (page_nid != -1) |
6688cc05 | 3432 | task_numa_fault(last_cpupid, page_nid, 1, flags); |
d10e63f2 MG |
3433 | return 0; |
3434 | } | |
3435 | ||
bae473a4 | 3436 | static int create_huge_pmd(struct fault_env *fe) |
b96375f7 | 3437 | { |
bae473a4 | 3438 | struct vm_area_struct *vma = fe->vma; |
fb6dd5fa | 3439 | if (vma_is_anonymous(vma)) |
bae473a4 | 3440 | return do_huge_pmd_anonymous_page(fe); |
b96375f7 | 3441 | if (vma->vm_ops->pmd_fault) |
bae473a4 KS |
3442 | return vma->vm_ops->pmd_fault(vma, fe->address, fe->pmd, |
3443 | fe->flags); | |
b96375f7 MW |
3444 | return VM_FAULT_FALLBACK; |
3445 | } | |
3446 | ||
bae473a4 | 3447 | static int wp_huge_pmd(struct fault_env *fe, pmd_t orig_pmd) |
b96375f7 | 3448 | { |
bae473a4 KS |
3449 | if (vma_is_anonymous(fe->vma)) |
3450 | return do_huge_pmd_wp_page(fe, orig_pmd); | |
3451 | if (fe->vma->vm_ops->pmd_fault) | |
3452 | return fe->vma->vm_ops->pmd_fault(fe->vma, fe->address, fe->pmd, | |
3453 | fe->flags); | |
af9e4d5f KS |
3454 | |
3455 | /* COW handled on pte level: split pmd */ | |
3456 | VM_BUG_ON_VMA(fe->vma->vm_flags & VM_SHARED, fe->vma); | |
3457 | split_huge_pmd(fe->vma, fe->pmd, fe->address); | |
3458 | ||
b96375f7 MW |
3459 | return VM_FAULT_FALLBACK; |
3460 | } | |
3461 | ||
38e08854 LS |
3462 | static inline bool vma_is_accessible(struct vm_area_struct *vma) |
3463 | { | |
3464 | return vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE); | |
3465 | } | |
3466 | ||
1da177e4 LT |
3467 | /* |
3468 | * These routines also need to handle stuff like marking pages dirty | |
3469 | * and/or accessed for architectures that don't do it in hardware (most | |
3470 | * RISC architectures). The early dirtying is also good on the i386. | |
3471 | * | |
3472 | * There is also a hook called "update_mmu_cache()" that architectures | |
3473 | * with external mmu caches can use to update those (ie the Sparc or | |
3474 | * PowerPC hashed page tables that act as extended TLBs). | |
3475 | * | |
7267ec00 KS |
3476 | * We enter with non-exclusive mmap_sem (to exclude vma changes, but allow |
3477 | * concurrent faults). | |
9a95f3cf | 3478 | * |
7267ec00 KS |
3479 | * The mmap_sem may have been released depending on flags and our return value. |
3480 | * See filemap_fault() and __lock_page_or_retry(). | |
1da177e4 | 3481 | */ |
bae473a4 | 3482 | static int handle_pte_fault(struct fault_env *fe) |
1da177e4 LT |
3483 | { |
3484 | pte_t entry; | |
3485 | ||
7267ec00 KS |
3486 | if (unlikely(pmd_none(*fe->pmd))) { |
3487 | /* | |
3488 | * Leave __pte_alloc() until later: because vm_ops->fault may | |
3489 | * want to allocate huge page, and if we expose page table | |
3490 | * for an instant, it will be difficult to retract from | |
3491 | * concurrent faults and from rmap lookups. | |
3492 | */ | |
3493 | fe->pte = NULL; | |
3494 | } else { | |
3495 | /* See comment in pte_alloc_one_map() */ | |
3496 | if (pmd_trans_unstable(fe->pmd) || pmd_devmap(*fe->pmd)) | |
3497 | return 0; | |
3498 | /* | |
3499 | * A regular pmd is established and it can't morph into a huge | |
3500 | * pmd from under us anymore at this point because we hold the | |
3501 | * mmap_sem read mode and khugepaged takes it in write mode. | |
3502 | * So now it's safe to run pte_offset_map(). | |
3503 | */ | |
3504 | fe->pte = pte_offset_map(fe->pmd, fe->address); | |
3505 | ||
3506 | entry = *fe->pte; | |
3507 | ||
3508 | /* | |
3509 | * some architectures can have larger ptes than wordsize, | |
3510 | * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and | |
3511 | * CONFIG_32BIT=y, so READ_ONCE or ACCESS_ONCE cannot guarantee | |
3512 | * atomic accesses. The code below just needs a consistent | |
3513 | * view for the ifs and we later double check anyway with the | |
3514 | * ptl lock held. So here a barrier will do. | |
3515 | */ | |
3516 | barrier(); | |
65500d23 | 3517 | if (pte_none(entry)) { |
7267ec00 KS |
3518 | pte_unmap(fe->pte); |
3519 | fe->pte = NULL; | |
65500d23 | 3520 | } |
1da177e4 LT |
3521 | } |
3522 | ||
7267ec00 KS |
3523 | if (!fe->pte) { |
3524 | if (vma_is_anonymous(fe->vma)) | |
3525 | return do_anonymous_page(fe); | |
3526 | else | |
3527 | return do_fault(fe); | |
3528 | } | |
3529 | ||
3530 | if (!pte_present(entry)) | |
3531 | return do_swap_page(fe, entry); | |
3532 | ||
38e08854 | 3533 | if (pte_protnone(entry) && vma_is_accessible(fe->vma)) |
bae473a4 | 3534 | return do_numa_page(fe, entry); |
d10e63f2 | 3535 | |
bae473a4 KS |
3536 | fe->ptl = pte_lockptr(fe->vma->vm_mm, fe->pmd); |
3537 | spin_lock(fe->ptl); | |
3538 | if (unlikely(!pte_same(*fe->pte, entry))) | |
8f4e2101 | 3539 | goto unlock; |
bae473a4 | 3540 | if (fe->flags & FAULT_FLAG_WRITE) { |
1da177e4 | 3541 | if (!pte_write(entry)) |
bae473a4 | 3542 | return do_wp_page(fe, entry); |
1da177e4 LT |
3543 | entry = pte_mkdirty(entry); |
3544 | } | |
3545 | entry = pte_mkyoung(entry); | |
bae473a4 KS |
3546 | if (ptep_set_access_flags(fe->vma, fe->address, fe->pte, entry, |
3547 | fe->flags & FAULT_FLAG_WRITE)) { | |
3548 | update_mmu_cache(fe->vma, fe->address, fe->pte); | |
1a44e149 AA |
3549 | } else { |
3550 | /* | |
3551 | * This is needed only for protection faults but the arch code | |
3552 | * is not yet telling us if this is a protection fault or not. | |
3553 | * This still avoids useless tlb flushes for .text page faults | |
3554 | * with threads. | |
3555 | */ | |
bae473a4 KS |
3556 | if (fe->flags & FAULT_FLAG_WRITE) |
3557 | flush_tlb_fix_spurious_fault(fe->vma, fe->address); | |
1a44e149 | 3558 | } |
8f4e2101 | 3559 | unlock: |
bae473a4 | 3560 | pte_unmap_unlock(fe->pte, fe->ptl); |
83c54070 | 3561 | return 0; |
1da177e4 LT |
3562 | } |
3563 | ||
3564 | /* | |
3565 | * By the time we get here, we already hold the mm semaphore | |
9a95f3cf PC |
3566 | * |
3567 | * The mmap_sem may have been released depending on flags and our | |
3568 | * return value. See filemap_fault() and __lock_page_or_retry(). | |
1da177e4 | 3569 | */ |
dcddffd4 KS |
3570 | static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address, |
3571 | unsigned int flags) | |
1da177e4 | 3572 | { |
bae473a4 KS |
3573 | struct fault_env fe = { |
3574 | .vma = vma, | |
3575 | .address = address, | |
3576 | .flags = flags, | |
3577 | }; | |
dcddffd4 | 3578 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 LT |
3579 | pgd_t *pgd; |
3580 | pud_t *pud; | |
1da177e4 | 3581 | |
1da177e4 | 3582 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
3583 | pud = pud_alloc(mm, pgd, address); |
3584 | if (!pud) | |
c74df32c | 3585 | return VM_FAULT_OOM; |
bae473a4 KS |
3586 | fe.pmd = pmd_alloc(mm, pud, address); |
3587 | if (!fe.pmd) | |
c74df32c | 3588 | return VM_FAULT_OOM; |
bae473a4 KS |
3589 | if (pmd_none(*fe.pmd) && transparent_hugepage_enabled(vma)) { |
3590 | int ret = create_huge_pmd(&fe); | |
c0292554 KS |
3591 | if (!(ret & VM_FAULT_FALLBACK)) |
3592 | return ret; | |
71e3aac0 | 3593 | } else { |
bae473a4 | 3594 | pmd_t orig_pmd = *fe.pmd; |
1f1d06c3 DR |
3595 | int ret; |
3596 | ||
71e3aac0 | 3597 | barrier(); |
5c7fb56e | 3598 | if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) { |
38e08854 | 3599 | if (pmd_protnone(orig_pmd) && vma_is_accessible(vma)) |
bae473a4 | 3600 | return do_huge_pmd_numa_page(&fe, orig_pmd); |
d10e63f2 | 3601 | |
bae473a4 KS |
3602 | if ((fe.flags & FAULT_FLAG_WRITE) && |
3603 | !pmd_write(orig_pmd)) { | |
3604 | ret = wp_huge_pmd(&fe, orig_pmd); | |
9845cbbd KS |
3605 | if (!(ret & VM_FAULT_FALLBACK)) |
3606 | return ret; | |
a1dd450b | 3607 | } else { |
bae473a4 | 3608 | huge_pmd_set_accessed(&fe, orig_pmd); |
9845cbbd | 3609 | return 0; |
1f1d06c3 | 3610 | } |
71e3aac0 AA |
3611 | } |
3612 | } | |
3613 | ||
bae473a4 | 3614 | return handle_pte_fault(&fe); |
1da177e4 LT |
3615 | } |
3616 | ||
9a95f3cf PC |
3617 | /* |
3618 | * By the time we get here, we already hold the mm semaphore | |
3619 | * | |
3620 | * The mmap_sem may have been released depending on flags and our | |
3621 | * return value. See filemap_fault() and __lock_page_or_retry(). | |
3622 | */ | |
dcddffd4 KS |
3623 | int handle_mm_fault(struct vm_area_struct *vma, unsigned long address, |
3624 | unsigned int flags) | |
519e5247 JW |
3625 | { |
3626 | int ret; | |
3627 | ||
3628 | __set_current_state(TASK_RUNNING); | |
3629 | ||
3630 | count_vm_event(PGFAULT); | |
dcddffd4 | 3631 | mem_cgroup_count_vm_event(vma->vm_mm, PGFAULT); |
519e5247 JW |
3632 | |
3633 | /* do counter updates before entering really critical section. */ | |
3634 | check_sync_rss_stat(current); | |
3635 | ||
3636 | /* | |
3637 | * Enable the memcg OOM handling for faults triggered in user | |
3638 | * space. Kernel faults are handled more gracefully. | |
3639 | */ | |
3640 | if (flags & FAULT_FLAG_USER) | |
49426420 | 3641 | mem_cgroup_oom_enable(); |
519e5247 | 3642 | |
bae473a4 KS |
3643 | if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, |
3644 | flags & FAULT_FLAG_INSTRUCTION, | |
3645 | flags & FAULT_FLAG_REMOTE)) | |
3646 | return VM_FAULT_SIGSEGV; | |
3647 | ||
3648 | if (unlikely(is_vm_hugetlb_page(vma))) | |
3649 | ret = hugetlb_fault(vma->vm_mm, vma, address, flags); | |
3650 | else | |
3651 | ret = __handle_mm_fault(vma, address, flags); | |
519e5247 | 3652 | |
49426420 JW |
3653 | if (flags & FAULT_FLAG_USER) { |
3654 | mem_cgroup_oom_disable(); | |
3655 | /* | |
3656 | * The task may have entered a memcg OOM situation but | |
3657 | * if the allocation error was handled gracefully (no | |
3658 | * VM_FAULT_OOM), there is no need to kill anything. | |
3659 | * Just clean up the OOM state peacefully. | |
3660 | */ | |
3661 | if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM)) | |
3662 | mem_cgroup_oom_synchronize(false); | |
3663 | } | |
3812c8c8 | 3664 | |
3f70dc38 MH |
3665 | /* |
3666 | * This mm has been already reaped by the oom reaper and so the | |
3667 | * refault cannot be trusted in general. Anonymous refaults would | |
3668 | * lose data and give a zero page instead e.g. This is especially | |
3669 | * problem for use_mm() because regular tasks will just die and | |
3670 | * the corrupted data will not be visible anywhere while kthread | |
3671 | * will outlive the oom victim and potentially propagate the date | |
3672 | * further. | |
3673 | */ | |
3674 | if (unlikely((current->flags & PF_KTHREAD) && !(ret & VM_FAULT_ERROR) | |
3675 | && test_bit(MMF_UNSTABLE, &vma->vm_mm->flags))) | |
3676 | ret = VM_FAULT_SIGBUS; | |
3677 | ||
519e5247 JW |
3678 | return ret; |
3679 | } | |
e1d6d01a | 3680 | EXPORT_SYMBOL_GPL(handle_mm_fault); |
519e5247 | 3681 | |
1da177e4 LT |
3682 | #ifndef __PAGETABLE_PUD_FOLDED |
3683 | /* | |
3684 | * Allocate page upper directory. | |
872fec16 | 3685 | * We've already handled the fast-path in-line. |
1da177e4 | 3686 | */ |
1bb3630e | 3687 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 3688 | { |
c74df32c HD |
3689 | pud_t *new = pud_alloc_one(mm, address); |
3690 | if (!new) | |
1bb3630e | 3691 | return -ENOMEM; |
1da177e4 | 3692 | |
362a61ad NP |
3693 | smp_wmb(); /* See comment in __pte_alloc */ |
3694 | ||
872fec16 | 3695 | spin_lock(&mm->page_table_lock); |
1bb3630e | 3696 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 3697 | pud_free(mm, new); |
1bb3630e HD |
3698 | else |
3699 | pgd_populate(mm, pgd, new); | |
c74df32c | 3700 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3701 | return 0; |
1da177e4 LT |
3702 | } |
3703 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
3704 | ||
3705 | #ifndef __PAGETABLE_PMD_FOLDED | |
3706 | /* | |
3707 | * Allocate page middle directory. | |
872fec16 | 3708 | * We've already handled the fast-path in-line. |
1da177e4 | 3709 | */ |
1bb3630e | 3710 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 3711 | { |
c74df32c HD |
3712 | pmd_t *new = pmd_alloc_one(mm, address); |
3713 | if (!new) | |
1bb3630e | 3714 | return -ENOMEM; |
1da177e4 | 3715 | |
362a61ad NP |
3716 | smp_wmb(); /* See comment in __pte_alloc */ |
3717 | ||
872fec16 | 3718 | spin_lock(&mm->page_table_lock); |
1da177e4 | 3719 | #ifndef __ARCH_HAS_4LEVEL_HACK |
dc6c9a35 KS |
3720 | if (!pud_present(*pud)) { |
3721 | mm_inc_nr_pmds(mm); | |
1bb3630e | 3722 | pud_populate(mm, pud, new); |
dc6c9a35 | 3723 | } else /* Another has populated it */ |
5e541973 | 3724 | pmd_free(mm, new); |
dc6c9a35 KS |
3725 | #else |
3726 | if (!pgd_present(*pud)) { | |
3727 | mm_inc_nr_pmds(mm); | |
1bb3630e | 3728 | pgd_populate(mm, pud, new); |
dc6c9a35 KS |
3729 | } else /* Another has populated it */ |
3730 | pmd_free(mm, new); | |
1da177e4 | 3731 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 3732 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3733 | return 0; |
e0f39591 | 3734 | } |
1da177e4 LT |
3735 | #endif /* __PAGETABLE_PMD_FOLDED */ |
3736 | ||
1b36ba81 | 3737 | static int __follow_pte(struct mm_struct *mm, unsigned long address, |
f8ad0f49 JW |
3738 | pte_t **ptepp, spinlock_t **ptlp) |
3739 | { | |
3740 | pgd_t *pgd; | |
3741 | pud_t *pud; | |
3742 | pmd_t *pmd; | |
3743 | pte_t *ptep; | |
3744 | ||
3745 | pgd = pgd_offset(mm, address); | |
3746 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
3747 | goto out; | |
3748 | ||
3749 | pud = pud_offset(pgd, address); | |
3750 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
3751 | goto out; | |
3752 | ||
3753 | pmd = pmd_offset(pud, address); | |
f66055ab | 3754 | VM_BUG_ON(pmd_trans_huge(*pmd)); |
f8ad0f49 JW |
3755 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) |
3756 | goto out; | |
3757 | ||
3758 | /* We cannot handle huge page PFN maps. Luckily they don't exist. */ | |
3759 | if (pmd_huge(*pmd)) | |
3760 | goto out; | |
3761 | ||
3762 | ptep = pte_offset_map_lock(mm, pmd, address, ptlp); | |
3763 | if (!ptep) | |
3764 | goto out; | |
3765 | if (!pte_present(*ptep)) | |
3766 | goto unlock; | |
3767 | *ptepp = ptep; | |
3768 | return 0; | |
3769 | unlock: | |
3770 | pte_unmap_unlock(ptep, *ptlp); | |
3771 | out: | |
3772 | return -EINVAL; | |
3773 | } | |
3774 | ||
1b36ba81 NK |
3775 | static inline int follow_pte(struct mm_struct *mm, unsigned long address, |
3776 | pte_t **ptepp, spinlock_t **ptlp) | |
3777 | { | |
3778 | int res; | |
3779 | ||
3780 | /* (void) is needed to make gcc happy */ | |
3781 | (void) __cond_lock(*ptlp, | |
3782 | !(res = __follow_pte(mm, address, ptepp, ptlp))); | |
3783 | return res; | |
3784 | } | |
3785 | ||
3b6748e2 JW |
3786 | /** |
3787 | * follow_pfn - look up PFN at a user virtual address | |
3788 | * @vma: memory mapping | |
3789 | * @address: user virtual address | |
3790 | * @pfn: location to store found PFN | |
3791 | * | |
3792 | * Only IO mappings and raw PFN mappings are allowed. | |
3793 | * | |
3794 | * Returns zero and the pfn at @pfn on success, -ve otherwise. | |
3795 | */ | |
3796 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, | |
3797 | unsigned long *pfn) | |
3798 | { | |
3799 | int ret = -EINVAL; | |
3800 | spinlock_t *ptl; | |
3801 | pte_t *ptep; | |
3802 | ||
3803 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
3804 | return ret; | |
3805 | ||
3806 | ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); | |
3807 | if (ret) | |
3808 | return ret; | |
3809 | *pfn = pte_pfn(*ptep); | |
3810 | pte_unmap_unlock(ptep, ptl); | |
3811 | return 0; | |
3812 | } | |
3813 | EXPORT_SYMBOL(follow_pfn); | |
3814 | ||
28b2ee20 | 3815 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
d87fe660 | 3816 | int follow_phys(struct vm_area_struct *vma, |
3817 | unsigned long address, unsigned int flags, | |
3818 | unsigned long *prot, resource_size_t *phys) | |
28b2ee20 | 3819 | { |
03668a4d | 3820 | int ret = -EINVAL; |
28b2ee20 RR |
3821 | pte_t *ptep, pte; |
3822 | spinlock_t *ptl; | |
28b2ee20 | 3823 | |
d87fe660 | 3824 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
3825 | goto out; | |
28b2ee20 | 3826 | |
03668a4d | 3827 | if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) |
d87fe660 | 3828 | goto out; |
28b2ee20 | 3829 | pte = *ptep; |
03668a4d | 3830 | |
28b2ee20 RR |
3831 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
3832 | goto unlock; | |
28b2ee20 RR |
3833 | |
3834 | *prot = pgprot_val(pte_pgprot(pte)); | |
03668a4d | 3835 | *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; |
28b2ee20 | 3836 | |
03668a4d | 3837 | ret = 0; |
28b2ee20 RR |
3838 | unlock: |
3839 | pte_unmap_unlock(ptep, ptl); | |
3840 | out: | |
d87fe660 | 3841 | return ret; |
28b2ee20 RR |
3842 | } |
3843 | ||
3844 | int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, | |
3845 | void *buf, int len, int write) | |
3846 | { | |
3847 | resource_size_t phys_addr; | |
3848 | unsigned long prot = 0; | |
2bc7273b | 3849 | void __iomem *maddr; |
28b2ee20 RR |
3850 | int offset = addr & (PAGE_SIZE-1); |
3851 | ||
d87fe660 | 3852 | if (follow_phys(vma, addr, write, &prot, &phys_addr)) |
28b2ee20 RR |
3853 | return -EINVAL; |
3854 | ||
9cb12d7b | 3855 | maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot); |
28b2ee20 RR |
3856 | if (write) |
3857 | memcpy_toio(maddr + offset, buf, len); | |
3858 | else | |
3859 | memcpy_fromio(buf, maddr + offset, len); | |
3860 | iounmap(maddr); | |
3861 | ||
3862 | return len; | |
3863 | } | |
5a73633e | 3864 | EXPORT_SYMBOL_GPL(generic_access_phys); |
28b2ee20 RR |
3865 | #endif |
3866 | ||
0ec76a11 | 3867 | /* |
206cb636 SW |
3868 | * Access another process' address space as given in mm. If non-NULL, use the |
3869 | * given task for page fault accounting. | |
0ec76a11 | 3870 | */ |
206cb636 SW |
3871 | static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm, |
3872 | unsigned long addr, void *buf, int len, int write) | |
0ec76a11 | 3873 | { |
0ec76a11 | 3874 | struct vm_area_struct *vma; |
0ec76a11 DH |
3875 | void *old_buf = buf; |
3876 | ||
0ec76a11 | 3877 | down_read(&mm->mmap_sem); |
183ff22b | 3878 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
3879 | while (len) { |
3880 | int bytes, ret, offset; | |
3881 | void *maddr; | |
28b2ee20 | 3882 | struct page *page = NULL; |
0ec76a11 | 3883 | |
1e987790 | 3884 | ret = get_user_pages_remote(tsk, mm, addr, 1, |
0ec76a11 | 3885 | write, 1, &page, &vma); |
28b2ee20 | 3886 | if (ret <= 0) { |
dbffcd03 RR |
3887 | #ifndef CONFIG_HAVE_IOREMAP_PROT |
3888 | break; | |
3889 | #else | |
28b2ee20 RR |
3890 | /* |
3891 | * Check if this is a VM_IO | VM_PFNMAP VMA, which | |
3892 | * we can access using slightly different code. | |
3893 | */ | |
28b2ee20 | 3894 | vma = find_vma(mm, addr); |
fe936dfc | 3895 | if (!vma || vma->vm_start > addr) |
28b2ee20 RR |
3896 | break; |
3897 | if (vma->vm_ops && vma->vm_ops->access) | |
3898 | ret = vma->vm_ops->access(vma, addr, buf, | |
3899 | len, write); | |
3900 | if (ret <= 0) | |
28b2ee20 RR |
3901 | break; |
3902 | bytes = ret; | |
dbffcd03 | 3903 | #endif |
0ec76a11 | 3904 | } else { |
28b2ee20 RR |
3905 | bytes = len; |
3906 | offset = addr & (PAGE_SIZE-1); | |
3907 | if (bytes > PAGE_SIZE-offset) | |
3908 | bytes = PAGE_SIZE-offset; | |
3909 | ||
3910 | maddr = kmap(page); | |
3911 | if (write) { | |
3912 | copy_to_user_page(vma, page, addr, | |
3913 | maddr + offset, buf, bytes); | |
3914 | set_page_dirty_lock(page); | |
3915 | } else { | |
3916 | copy_from_user_page(vma, page, addr, | |
3917 | buf, maddr + offset, bytes); | |
3918 | } | |
3919 | kunmap(page); | |
09cbfeaf | 3920 | put_page(page); |
0ec76a11 | 3921 | } |
0ec76a11 DH |
3922 | len -= bytes; |
3923 | buf += bytes; | |
3924 | addr += bytes; | |
3925 | } | |
3926 | up_read(&mm->mmap_sem); | |
0ec76a11 DH |
3927 | |
3928 | return buf - old_buf; | |
3929 | } | |
03252919 | 3930 | |
5ddd36b9 | 3931 | /** |
ae91dbfc | 3932 | * access_remote_vm - access another process' address space |
5ddd36b9 SW |
3933 | * @mm: the mm_struct of the target address space |
3934 | * @addr: start address to access | |
3935 | * @buf: source or destination buffer | |
3936 | * @len: number of bytes to transfer | |
3937 | * @write: whether the access is a write | |
3938 | * | |
3939 | * The caller must hold a reference on @mm. | |
3940 | */ | |
3941 | int access_remote_vm(struct mm_struct *mm, unsigned long addr, | |
3942 | void *buf, int len, int write) | |
3943 | { | |
3944 | return __access_remote_vm(NULL, mm, addr, buf, len, write); | |
3945 | } | |
3946 | ||
206cb636 SW |
3947 | /* |
3948 | * Access another process' address space. | |
3949 | * Source/target buffer must be kernel space, | |
3950 | * Do not walk the page table directly, use get_user_pages | |
3951 | */ | |
3952 | int access_process_vm(struct task_struct *tsk, unsigned long addr, | |
3953 | void *buf, int len, int write) | |
3954 | { | |
3955 | struct mm_struct *mm; | |
3956 | int ret; | |
3957 | ||
3958 | mm = get_task_mm(tsk); | |
3959 | if (!mm) | |
3960 | return 0; | |
3961 | ||
3962 | ret = __access_remote_vm(tsk, mm, addr, buf, len, write); | |
3963 | mmput(mm); | |
3964 | ||
3965 | return ret; | |
3966 | } | |
3967 | ||
03252919 AK |
3968 | /* |
3969 | * Print the name of a VMA. | |
3970 | */ | |
3971 | void print_vma_addr(char *prefix, unsigned long ip) | |
3972 | { | |
3973 | struct mm_struct *mm = current->mm; | |
3974 | struct vm_area_struct *vma; | |
3975 | ||
e8bff74a IM |
3976 | /* |
3977 | * Do not print if we are in atomic | |
3978 | * contexts (in exception stacks, etc.): | |
3979 | */ | |
3980 | if (preempt_count()) | |
3981 | return; | |
3982 | ||
03252919 AK |
3983 | down_read(&mm->mmap_sem); |
3984 | vma = find_vma(mm, ip); | |
3985 | if (vma && vma->vm_file) { | |
3986 | struct file *f = vma->vm_file; | |
3987 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
3988 | if (buf) { | |
2fbc57c5 | 3989 | char *p; |
03252919 | 3990 | |
9bf39ab2 | 3991 | p = file_path(f, buf, PAGE_SIZE); |
03252919 AK |
3992 | if (IS_ERR(p)) |
3993 | p = "?"; | |
2fbc57c5 | 3994 | printk("%s%s[%lx+%lx]", prefix, kbasename(p), |
03252919 AK |
3995 | vma->vm_start, |
3996 | vma->vm_end - vma->vm_start); | |
3997 | free_page((unsigned long)buf); | |
3998 | } | |
3999 | } | |
51a07e50 | 4000 | up_read(&mm->mmap_sem); |
03252919 | 4001 | } |
3ee1afa3 | 4002 | |
662bbcb2 | 4003 | #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP) |
9ec23531 | 4004 | void __might_fault(const char *file, int line) |
3ee1afa3 | 4005 | { |
95156f00 PZ |
4006 | /* |
4007 | * Some code (nfs/sunrpc) uses socket ops on kernel memory while | |
4008 | * holding the mmap_sem, this is safe because kernel memory doesn't | |
4009 | * get paged out, therefore we'll never actually fault, and the | |
4010 | * below annotations will generate false positives. | |
4011 | */ | |
4012 | if (segment_eq(get_fs(), KERNEL_DS)) | |
4013 | return; | |
9ec23531 | 4014 | if (pagefault_disabled()) |
662bbcb2 | 4015 | return; |
9ec23531 DH |
4016 | __might_sleep(file, line, 0); |
4017 | #if defined(CONFIG_DEBUG_ATOMIC_SLEEP) | |
662bbcb2 | 4018 | if (current->mm) |
3ee1afa3 | 4019 | might_lock_read(¤t->mm->mmap_sem); |
9ec23531 | 4020 | #endif |
3ee1afa3 | 4021 | } |
9ec23531 | 4022 | EXPORT_SYMBOL(__might_fault); |
3ee1afa3 | 4023 | #endif |
47ad8475 AA |
4024 | |
4025 | #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS) | |
4026 | static void clear_gigantic_page(struct page *page, | |
4027 | unsigned long addr, | |
4028 | unsigned int pages_per_huge_page) | |
4029 | { | |
4030 | int i; | |
4031 | struct page *p = page; | |
4032 | ||
4033 | might_sleep(); | |
4034 | for (i = 0; i < pages_per_huge_page; | |
4035 | i++, p = mem_map_next(p, page, i)) { | |
4036 | cond_resched(); | |
4037 | clear_user_highpage(p, addr + i * PAGE_SIZE); | |
4038 | } | |
4039 | } | |
4040 | void clear_huge_page(struct page *page, | |
4041 | unsigned long addr, unsigned int pages_per_huge_page) | |
4042 | { | |
4043 | int i; | |
4044 | ||
4045 | if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { | |
4046 | clear_gigantic_page(page, addr, pages_per_huge_page); | |
4047 | return; | |
4048 | } | |
4049 | ||
4050 | might_sleep(); | |
4051 | for (i = 0; i < pages_per_huge_page; i++) { | |
4052 | cond_resched(); | |
4053 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); | |
4054 | } | |
4055 | } | |
4056 | ||
4057 | static void copy_user_gigantic_page(struct page *dst, struct page *src, | |
4058 | unsigned long addr, | |
4059 | struct vm_area_struct *vma, | |
4060 | unsigned int pages_per_huge_page) | |
4061 | { | |
4062 | int i; | |
4063 | struct page *dst_base = dst; | |
4064 | struct page *src_base = src; | |
4065 | ||
4066 | for (i = 0; i < pages_per_huge_page; ) { | |
4067 | cond_resched(); | |
4068 | copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma); | |
4069 | ||
4070 | i++; | |
4071 | dst = mem_map_next(dst, dst_base, i); | |
4072 | src = mem_map_next(src, src_base, i); | |
4073 | } | |
4074 | } | |
4075 | ||
4076 | void copy_user_huge_page(struct page *dst, struct page *src, | |
4077 | unsigned long addr, struct vm_area_struct *vma, | |
4078 | unsigned int pages_per_huge_page) | |
4079 | { | |
4080 | int i; | |
4081 | ||
4082 | if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) { | |
4083 | copy_user_gigantic_page(dst, src, addr, vma, | |
4084 | pages_per_huge_page); | |
4085 | return; | |
4086 | } | |
4087 | ||
4088 | might_sleep(); | |
4089 | for (i = 0; i < pages_per_huge_page; i++) { | |
4090 | cond_resched(); | |
4091 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); | |
4092 | } | |
4093 | } | |
4094 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ | |
49076ec2 | 4095 | |
40b64acd | 4096 | #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS |
b35f1819 KS |
4097 | |
4098 | static struct kmem_cache *page_ptl_cachep; | |
4099 | ||
4100 | void __init ptlock_cache_init(void) | |
4101 | { | |
4102 | page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0, | |
4103 | SLAB_PANIC, NULL); | |
4104 | } | |
4105 | ||
539edb58 | 4106 | bool ptlock_alloc(struct page *page) |
49076ec2 KS |
4107 | { |
4108 | spinlock_t *ptl; | |
4109 | ||
b35f1819 | 4110 | ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL); |
49076ec2 KS |
4111 | if (!ptl) |
4112 | return false; | |
539edb58 | 4113 | page->ptl = ptl; |
49076ec2 KS |
4114 | return true; |
4115 | } | |
4116 | ||
539edb58 | 4117 | void ptlock_free(struct page *page) |
49076ec2 | 4118 | { |
b35f1819 | 4119 | kmem_cache_free(page_ptl_cachep, page->ptl); |
49076ec2 KS |
4120 | } |
4121 | #endif |