Branch data Line data Source code
1 : : /*
2 : : * linux/mm/memory.c
3 : : *
4 : : * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 : : */
6 : :
7 : : /*
8 : : * demand-loading started 01.12.91 - seems it is high on the list of
9 : : * things wanted, and it should be easy to implement. - Linus
10 : : */
11 : :
12 : : /*
13 : : * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 : : * pages started 02.12.91, seems to work. - Linus.
15 : : *
16 : : * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 : : * would have taken more than the 6M I have free, but it worked well as
18 : : * far as I could see.
19 : : *
20 : : * Also corrected some "invalidate()"s - I wasn't doing enough of them.
21 : : */
22 : :
23 : : /*
24 : : * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 : : * thought has to go into this. Oh, well..
26 : : * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 : : * Found it. Everything seems to work now.
28 : : * 20.12.91 - Ok, making the swap-device changeable like the root.
29 : : */
30 : :
31 : : /*
32 : : * 05.04.94 - Multi-page memory management added for v1.1.
33 : : * Idea by Alex Bligh (alex@cconcepts.co.uk)
34 : : *
35 : : * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 : : * (Gerhard.Wichert@pdb.siemens.de)
37 : : *
38 : : * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
39 : : */
40 : :
41 : : #include <linux/kernel_stat.h>
42 : : #include <linux/mm.h>
43 : : #include <linux/hugetlb.h>
44 : : #include <linux/mman.h>
45 : : #include <linux/swap.h>
46 : : #include <linux/highmem.h>
47 : : #include <linux/pagemap.h>
48 : : #include <linux/ksm.h>
49 : : #include <linux/rmap.h>
50 : : #include <linux/export.h>
51 : : #include <linux/delayacct.h>
52 : : #include <linux/init.h>
53 : : #include <linux/writeback.h>
54 : : #include <linux/memcontrol.h>
55 : : #include <linux/mmu_notifier.h>
56 : : #include <linux/kallsyms.h>
57 : : #include <linux/swapops.h>
58 : : #include <linux/elf.h>
59 : : #include <linux/gfp.h>
60 : : #include <linux/migrate.h>
61 : : #include <linux/string.h>
62 : :
63 : : #include <asm/io.h>
64 : : #include <asm/pgalloc.h>
65 : : #include <asm/uaccess.h>
66 : : #include <asm/tlb.h>
67 : : #include <asm/tlbflush.h>
68 : : #include <asm/pgtable.h>
69 : :
70 : : #include "internal.h"
71 : :
72 : : #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS
73 : : #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
74 : : #endif
75 : :
76 : : #ifndef CONFIG_NEED_MULTIPLE_NODES
77 : : /* use the per-pgdat data instead for discontigmem - mbligh */
78 : : unsigned long max_mapnr;
79 : : struct page *mem_map;
80 : :
81 : : EXPORT_SYMBOL(max_mapnr);
82 : : EXPORT_SYMBOL(mem_map);
83 : : #endif
84 : :
85 : : /*
86 : : * A number of key systems in x86 including ioremap() rely on the assumption
87 : : * that high_memory defines the upper bound on direct map memory, then end
88 : : * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
89 : : * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
90 : : * and ZONE_HIGHMEM.
91 : : */
92 : : void * high_memory;
93 : :
94 : : EXPORT_SYMBOL(high_memory);
95 : :
96 : : /*
97 : : * Randomize the address space (stacks, mmaps, brk, etc.).
98 : : *
99 : : * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
100 : : * as ancient (libc5 based) binaries can segfault. )
101 : : */
102 : : int randomize_va_space __read_mostly =
103 : : #ifdef CONFIG_COMPAT_BRK
104 : : 1;
105 : : #else
106 : : 2;
107 : : #endif
108 : :
109 : 0 : static int __init disable_randmaps(char *s)
110 : : {
111 : 0 : randomize_va_space = 0;
112 : 0 : return 1;
113 : : }
114 : : __setup("norandmaps", disable_randmaps);
115 : :
116 : : unsigned long zero_pfn __read_mostly;
117 : : unsigned long highest_memmap_pfn __read_mostly;
118 : :
119 : : /*
120 : : * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
121 : : */
122 : 0 : static int __init init_zero_pfn(void)
123 : : {
124 : 0 : zero_pfn = page_to_pfn(ZERO_PAGE(0));
125 : 0 : return 0;
126 : : }
127 : : core_initcall(init_zero_pfn);
128 : :
129 : :
130 : : #if defined(SPLIT_RSS_COUNTING)
131 : :
132 : 0 : void sync_mm_rss(struct mm_struct *mm)
133 : : {
134 : : int i;
135 : :
136 [ + + ]: 15887175 : for (i = 0; i < NR_MM_COUNTERS; i++) {
137 [ + + ]: 11915298 : if (current->rss_stat.count[i]) {
138 : 0 : add_mm_counter(mm, i, current->rss_stat.count[i]);
139 : 3817239 : current->rss_stat.count[i] = 0;
140 : : }
141 : : }
142 : 3971877 : current->rss_stat.events = 0;
143 : 3971877 : }
144 : :
145 : 0 : static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
146 : : {
147 : 58211161 : struct task_struct *task = current;
148 : :
149 [ + + ]: 58211161 : if (likely(task->mm == mm))
150 : 56233449 : task->rss_stat.count[member] += val;
151 : : else
152 : : add_mm_counter(mm, member, val);
153 : 58211159 : }
154 : : #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
155 : : #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
156 : :
157 : : /* sync counter once per 64 page faults */
158 : : #define TASK_RSS_EVENTS_THRESH (64)
159 : 0 : static void check_sync_rss_stat(struct task_struct *task)
160 : : {
161 [ + ]: 88044859 : if (unlikely(task != current))
162 : 0 : return;
163 [ + + ]: 88045082 : if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
164 : 446618 : sync_mm_rss(task->mm);
165 : : }
166 : : #else /* SPLIT_RSS_COUNTING */
167 : :
168 : : #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
169 : : #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
170 : :
171 : : static void check_sync_rss_stat(struct task_struct *task)
172 : : {
173 : : }
174 : :
175 : : #endif /* SPLIT_RSS_COUNTING */
176 : :
177 : : #ifdef HAVE_GENERIC_MMU_GATHER
178 : :
179 : : static int tlb_next_batch(struct mmu_gather *tlb)
180 : : {
181 : : struct mmu_gather_batch *batch;
182 : :
183 : : batch = tlb->active;
184 : : if (batch->next) {
185 : : tlb->active = batch->next;
186 : : return 1;
187 : : }
188 : :
189 : : if (tlb->batch_count == MAX_GATHER_BATCH_COUNT)
190 : : return 0;
191 : :
192 : : batch = (void *)__get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
193 : : if (!batch)
194 : : return 0;
195 : :
196 : : tlb->batch_count++;
197 : : batch->next = NULL;
198 : : batch->nr = 0;
199 : : batch->max = MAX_GATHER_BATCH;
200 : :
201 : : tlb->active->next = batch;
202 : : tlb->active = batch;
203 : :
204 : : return 1;
205 : : }
206 : :
207 : : /* tlb_gather_mmu
208 : : * Called to initialize an (on-stack) mmu_gather structure for page-table
209 : : * tear-down from @mm. The @fullmm argument is used when @mm is without
210 : : * users and we're going to destroy the full address space (exit/execve).
211 : : */
212 : : void tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
213 : : {
214 : : tlb->mm = mm;
215 : :
216 : : /* Is it from 0 to ~0? */
217 : : tlb->fullmm = !(start | (end+1));
218 : : tlb->need_flush_all = 0;
219 : : tlb->start = start;
220 : : tlb->end = end;
221 : : tlb->need_flush = 0;
222 : : tlb->local.next = NULL;
223 : : tlb->local.nr = 0;
224 : : tlb->local.max = ARRAY_SIZE(tlb->__pages);
225 : : tlb->active = &tlb->local;
226 : : tlb->batch_count = 0;
227 : :
228 : : #ifdef CONFIG_HAVE_RCU_TABLE_FREE
229 : : tlb->batch = NULL;
230 : : #endif
231 : : }
232 : :
233 : : void tlb_flush_mmu(struct mmu_gather *tlb)
234 : : {
235 : : struct mmu_gather_batch *batch;
236 : :
237 : : if (!tlb->need_flush)
238 : : return;
239 : : tlb->need_flush = 0;
240 : : tlb_flush(tlb);
241 : : #ifdef CONFIG_HAVE_RCU_TABLE_FREE
242 : : tlb_table_flush(tlb);
243 : : #endif
244 : :
245 : : for (batch = &tlb->local; batch; batch = batch->next) {
246 : : free_pages_and_swap_cache(batch->pages, batch->nr);
247 : : batch->nr = 0;
248 : : }
249 : : tlb->active = &tlb->local;
250 : : }
251 : :
252 : : /* tlb_finish_mmu
253 : : * Called at the end of the shootdown operation to free up any resources
254 : : * that were required.
255 : : */
256 : : void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
257 : : {
258 : : struct mmu_gather_batch *batch, *next;
259 : :
260 : : tlb_flush_mmu(tlb);
261 : :
262 : : /* keep the page table cache within bounds */
263 : : check_pgt_cache();
264 : :
265 : : for (batch = tlb->local.next; batch; batch = next) {
266 : : next = batch->next;
267 : : free_pages((unsigned long)batch, 0);
268 : : }
269 : : tlb->local.next = NULL;
270 : : }
271 : :
272 : : /* __tlb_remove_page
273 : : * Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)), while
274 : : * handling the additional races in SMP caused by other CPUs caching valid
275 : : * mappings in their TLBs. Returns the number of free page slots left.
276 : : * When out of page slots we must call tlb_flush_mmu().
277 : : */
278 : : int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
279 : : {
280 : : struct mmu_gather_batch *batch;
281 : :
282 : : VM_BUG_ON(!tlb->need_flush);
283 : :
284 : : batch = tlb->active;
285 : : batch->pages[batch->nr++] = page;
286 : : if (batch->nr == batch->max) {
287 : : if (!tlb_next_batch(tlb))
288 : : return 0;
289 : : batch = tlb->active;
290 : : }
291 : : VM_BUG_ON(batch->nr > batch->max);
292 : :
293 : : return batch->max - batch->nr;
294 : : }
295 : :
296 : : #endif /* HAVE_GENERIC_MMU_GATHER */
297 : :
298 : : #ifdef CONFIG_HAVE_RCU_TABLE_FREE
299 : :
300 : : /*
301 : : * See the comment near struct mmu_table_batch.
302 : : */
303 : :
304 : : static void tlb_remove_table_smp_sync(void *arg)
305 : : {
306 : : /* Simply deliver the interrupt */
307 : : }
308 : :
309 : : static void tlb_remove_table_one(void *table)
310 : : {
311 : : /*
312 : : * This isn't an RCU grace period and hence the page-tables cannot be
313 : : * assumed to be actually RCU-freed.
314 : : *
315 : : * It is however sufficient for software page-table walkers that rely on
316 : : * IRQ disabling. See the comment near struct mmu_table_batch.
317 : : */
318 : : smp_call_function(tlb_remove_table_smp_sync, NULL, 1);
319 : : __tlb_remove_table(table);
320 : : }
321 : :
322 : : static void tlb_remove_table_rcu(struct rcu_head *head)
323 : : {
324 : : struct mmu_table_batch *batch;
325 : : int i;
326 : :
327 : : batch = container_of(head, struct mmu_table_batch, rcu);
328 : :
329 : : for (i = 0; i < batch->nr; i++)
330 : : __tlb_remove_table(batch->tables[i]);
331 : :
332 : : free_page((unsigned long)batch);
333 : : }
334 : :
335 : : void tlb_table_flush(struct mmu_gather *tlb)
336 : : {
337 : : struct mmu_table_batch **batch = &tlb->batch;
338 : :
339 : : if (*batch) {
340 : : call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu);
341 : : *batch = NULL;
342 : : }
343 : : }
344 : :
345 : : void tlb_remove_table(struct mmu_gather *tlb, void *table)
346 : : {
347 : : struct mmu_table_batch **batch = &tlb->batch;
348 : :
349 : : tlb->need_flush = 1;
350 : :
351 : : /*
352 : : * When there's less then two users of this mm there cannot be a
353 : : * concurrent page-table walk.
354 : : */
355 : : if (atomic_read(&tlb->mm->mm_users) < 2) {
356 : : __tlb_remove_table(table);
357 : : return;
358 : : }
359 : :
360 : : if (*batch == NULL) {
361 : : *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN);
362 : : if (*batch == NULL) {
363 : : tlb_remove_table_one(table);
364 : : return;
365 : : }
366 : : (*batch)->nr = 0;
367 : : }
368 : : (*batch)->tables[(*batch)->nr++] = table;
369 : : if ((*batch)->nr == MAX_TABLE_BATCH)
370 : : tlb_table_flush(tlb);
371 : : }
372 : :
373 : : #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
374 : :
375 : : /*
376 : : * Note: this doesn't free the actual pages themselves. That
377 : : * has been handled earlier when unmapping all the memory regions.
378 : : */
379 : 0 : static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
380 : : unsigned long addr)
381 : : {
382 : 3796981 : pgtable_t token = pmd_pgtable(*pmd);
383 : 3796981 : pmd_clear(pmd);
384 : : pte_free_tlb(tlb, token, addr);
385 : 6 : atomic_long_dec(&tlb->mm->nr_ptes);
386 : 3796970 : }
387 : :
388 : : static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
389 : : unsigned long addr, unsigned long end,
390 : : unsigned long floor, unsigned long ceiling)
391 : : {
392 : : pmd_t *pmd;
393 : : unsigned long next;
394 : : unsigned long start;
395 : :
396 : : start = addr;
397 : : pmd = pmd_offset(pud, addr);
398 : : do {
399 : : next = pmd_addr_end(addr, end);
400 [ + + ]: 3964975 : if (pmd_none_or_clear_bad(pmd))
401 : 167995 : continue;
402 : 3796980 : free_pte_range(tlb, pmd, addr);
403 : : } while (pmd++, addr = next, addr != end);
404 : :
405 : : start &= PUD_MASK;
406 : : if (start < floor)
407 : : return;
408 : : if (ceiling) {
409 : : ceiling &= PUD_MASK;
410 : : if (!ceiling)
411 : : return;
412 : : }
413 : : if (end - 1 > ceiling - 1)
414 : : return;
415 : :
416 : : pmd = pmd_offset(pud, start);
417 : : pud_clear(pud);
418 : : pmd_free_tlb(tlb, pmd, start);
419 : : }
420 : :
421 : : static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
422 : : unsigned long addr, unsigned long end,
423 : : unsigned long floor, unsigned long ceiling)
424 : : {
425 : : pud_t *pud;
426 : : unsigned long next;
427 : : unsigned long start;
428 : :
429 : : start = addr;
430 : : pud = pud_offset(pgd, addr);
431 : : do {
432 : : next = pud_addr_end(addr, end);
433 : : if (pud_none_or_clear_bad(pud))
434 : : continue;
435 : : free_pmd_range(tlb, pud, addr, next, floor, ceiling);
436 : : } while (pud++, addr = next, addr != end);
437 : :
438 : : start &= PGDIR_MASK;
439 : : if (start < floor)
440 : : return;
441 : : if (ceiling) {
442 : : ceiling &= PGDIR_MASK;
443 : : if (!ceiling)
444 : : return;
445 : : }
446 : : if (end - 1 > ceiling - 1)
447 : : return;
448 : :
449 : : pud = pud_offset(pgd, start);
450 : : pgd_clear(pgd);
451 : : pud_free_tlb(tlb, pud, start);
452 : : }
453 : :
454 : : /*
455 : : * This function frees user-level page tables of a process.
456 : : */
457 : 0 : void free_pgd_range(struct mmu_gather *tlb,
458 : : unsigned long addr, unsigned long end,
459 : : unsigned long floor, unsigned long ceiling)
460 : : {
461 : : pgd_t *pgd;
462 : : unsigned long next;
463 : :
464 : : /*
465 : : * The next few lines have given us lots of grief...
466 : : *
467 : : * Why are we testing PMD* at this top level? Because often
468 : : * there will be no work to do at all, and we'd prefer not to
469 : : * go all the way down to the bottom just to discover that.
470 : : *
471 : : * Why all these "- 1"s? Because 0 represents both the bottom
472 : : * of the address space and the top of it (using -1 for the
473 : : * top wouldn't help much: the masks would do the wrong thing).
474 : : * The rule is that addr 0 and floor 0 refer to the bottom of
475 : : * the address space, but end 0 and ceiling 0 refer to the top
476 : : * Comparisons need to use "end - 1" and "ceiling - 1" (though
477 : : * that end 0 case should be mythical).
478 : : *
479 : : * Wherever addr is brought up or ceiling brought down, we must
480 : : * be careful to reject "the opposite 0" before it confuses the
481 : : * subsequent tests. But what about where end is brought down
482 : : * by PMD_SIZE below? no, end can't go down to 0 there.
483 : : *
484 : : * Whereas we round start (addr) and ceiling down, by different
485 : : * masks at different levels, in order to test whether a table
486 : : * now has no other vmas using it, so can be freed, we don't
487 : : * bother to round floor or end up - the tests don't need that.
488 : : */
489 : :
490 : 5998580 : addr &= PMD_MASK;
491 [ + + ]: 5998580 : if (addr < floor) {
492 : 2341873 : addr += PMD_SIZE;
493 [ + ]: 2341873 : if (!addr)
494 : : return;
495 : : }
496 [ + + ]: 11997176 : if (ceiling) {
497 : 4743186 : ceiling &= PMD_MASK;
498 [ + + ]: 4743186 : if (!ceiling)
499 : : return;
500 : : }
501 [ + + ]: 5998591 : if (end - 1 > ceiling - 1)
502 : 664542 : end -= PMD_SIZE;
503 [ + + ]: 5998591 : if (addr > end - 1)
504 : : return;
505 : :
506 : 3661852 : pgd = pgd_offset(tlb->mm, addr);
507 : : do {
508 [ + + ]: 3965046 : next = pgd_addr_end(addr, end);
509 : : if (pgd_none_or_clear_bad(pgd))
510 : : continue;
511 : : free_pud_range(tlb, pgd, addr, next, floor, ceiling);
512 [ + + ]: 3965033 : } while (pgd++, addr = next, addr != end);
513 : : }
514 : :
515 : 0 : void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
516 : : unsigned long floor, unsigned long ceiling)
517 : : {
518 [ + + ]: 8315376 : while (vma) {
519 : 5939626 : struct vm_area_struct *next = vma->vm_next;
520 : 5939626 : unsigned long addr = vma->vm_start;
521 : :
522 : : /*
523 : : * Hide vma from rmap and truncate_pagecache before freeing
524 : : * pgtables
525 : : */
526 : 5939626 : unlink_anon_vmas(vma);
527 : 5939610 : unlink_file_vma(vma);
528 : :
529 : : if (is_vm_hugetlb_page(vma)) {
530 : : hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
531 : : floor, next? next->vm_start: ceiling);
532 : : } else {
533 : : /*
534 : : * Optimization: gather nearby vmas into one call down
535 : : */
536 [ + + ][ + + ]: 25672977 : while (next && next->vm_start <= vma->vm_end + PMD_SIZE
537 : : && !is_vm_hugetlb_page(next)) {
538 : : vma = next;
539 : 17357571 : next = vma->vm_next;
540 : 17357571 : unlink_anon_vmas(vma);
541 : 17357092 : unlink_file_vma(vma);
542 : : }
543 [ + + ]: 5939638 : free_pgd_range(tlb, addr, vma->vm_end,
544 : : floor, next? next->vm_start: ceiling);
545 : : }
546 : : vma = next;
547 : : }
548 : 2375750 : }
549 : :
550 : 0 : int __pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma,
551 : : pmd_t *pmd, unsigned long address)
552 : : {
553 : : spinlock_t *ptl;
554 : : pgtable_t new = pte_alloc_one(mm, address);
555 : : int wait_split_huge_page;
556 [ + + ]: 4992046 : if (!new)
557 : : return -ENOMEM;
558 : :
559 : : /*
560 : : * Ensure all pte setup (eg. pte page lock and page clearing) are
561 : : * visible before the pte is made visible to other CPUs by being
562 : : * put into page tables.
563 : : *
564 : : * The other side of the story is the pointer chasing in the page
565 : : * table walking code (when walking the page table without locking;
566 : : * ie. most of the time). Fortunately, these data accesses consist
567 : : * of a chain of data-dependent loads, meaning most CPUs (alpha
568 : : * being the notable exception) will already guarantee loads are
569 : : * seen in-order. See the alpha page table accessors for the
570 : : * smp_read_barrier_depends() barriers in page table walking code.
571 : : */
572 : 4992035 : smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
573 : :
574 : : ptl = pmd_lock(mm, pmd);
575 : : wait_split_huge_page = 0;
576 [ + + ]: 4992134 : if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
577 : 4992094 : atomic_long_inc(&mm->nr_ptes);
578 : : pmd_populate(mm, pmd, new);
579 : : new = NULL;
580 : : } else if (unlikely(pmd_trans_splitting(*pmd)))
581 : : wait_split_huge_page = 1;
582 : : spin_unlock(ptl);
583 [ + + ]: 4992125 : if (new)
584 : : pte_free(mm, new);
585 : : if (wait_split_huge_page)
586 : : wait_split_huge_page(vma->anon_vma, pmd);
587 : : return 0;
588 : : }
589 : :
590 : 0 : int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
591 : : {
592 : : pte_t *new = pte_alloc_one_kernel(&init_mm, address);
593 [ + - ]: 30 : if (!new)
594 : : return -ENOMEM;
595 : :
596 : 30 : smp_wmb(); /* See comment in __pte_alloc */
597 : :
598 : : spin_lock(&init_mm.page_table_lock);
599 [ + - ]: 30 : if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
600 : : pmd_populate_kernel(&init_mm, pmd, new);
601 : : new = NULL;
602 : : } else
603 : : VM_BUG_ON(pmd_trans_splitting(*pmd));
604 : : spin_unlock(&init_mm.page_table_lock);
605 [ - + ]: 30 : if (new)
606 : : pte_free_kernel(&init_mm, new);
607 : : return 0;
608 : : }
609 : :
610 : : static inline void init_rss_vec(int *rss)
611 : : {
612 : 35281920 : memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
613 : : }
614 : :
615 : : static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
616 : : {
617 : : int i;
618 : :
619 [ + + - + ]: 35281931 : if (current->mm == mm)
620 : 35281931 : sync_mm_rss(mm);
621 [ + + ][ + + ]: 141126583 : for (i = 0; i < NR_MM_COUNTERS; i++)
622 [ + + ][ + + ]: 105844454 : if (rss[i])
623 : : add_mm_counter(mm, i, rss[i]);
624 : : }
625 : :
626 : : /*
627 : : * This function is called to print an error when a bad pte
628 : : * is found. For example, we might have a PFN-mapped pte in
629 : : * a region that doesn't allow it.
630 : : *
631 : : * The calling function must still handle the error.
632 : : */
633 : 0 : static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
634 : : pte_t pte, struct page *page)
635 : : {
636 : 0 : pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
637 : : pud_t *pud = pud_offset(pgd, addr);
638 : : pmd_t *pmd = pmd_offset(pud, addr);
639 : : struct address_space *mapping;
640 : : pgoff_t index;
641 : : static unsigned long resume;
642 : : static unsigned long nr_shown;
643 : : static unsigned long nr_unshown;
644 : :
645 : : /*
646 : : * Allow a burst of 60 reports, then keep quiet for that minute;
647 : : * or allow a steady drip of one report per second.
648 : : */
649 [ # # ]: 0 : if (nr_shown == 60) {
650 [ # # ]: 0 : if (time_before(jiffies, resume)) {
651 : 0 : nr_unshown++;
652 : 0 : return;
653 : : }
654 [ # # ]: 0 : if (nr_unshown) {
655 : 0 : printk(KERN_ALERT
656 : : "BUG: Bad page map: %lu messages suppressed\n",
657 : : nr_unshown);
658 : 0 : nr_unshown = 0;
659 : : }
660 : 0 : nr_shown = 0;
661 : : }
662 [ # # ]: 0 : if (nr_shown++ == 0)
663 : 0 : resume = jiffies + 60 * HZ;
664 : :
665 [ # # ]: 0 : mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
666 : : index = linear_page_index(vma, addr);
667 : :
668 : 0 : printk(KERN_ALERT
669 : : "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
670 : 0 : current->comm,
671 : 0 : (long long)pte_val(pte), (long long)pmd_val(*pmd));
672 [ # # ]: 0 : if (page)
673 : 0 : dump_page(page);
674 : 0 : printk(KERN_ALERT
675 : : "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
676 : : (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
677 : : /*
678 : : * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
679 : : */
680 [ # # ]: 0 : if (vma->vm_ops)
681 : 0 : printk(KERN_ALERT "vma->vm_ops->fault: %pSR\n",
682 : : vma->vm_ops->fault);
683 [ # # ]: 0 : if (vma->vm_file)
684 : 0 : printk(KERN_ALERT "vma->vm_file->f_op->mmap: %pSR\n",
685 : 0 : vma->vm_file->f_op->mmap);
686 : 0 : dump_stack();
687 : 0 : add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
688 : : }
689 : :
690 : : static inline bool is_cow_mapping(vm_flags_t flags)
691 : : {
692 : 26690732 : return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
693 : : }
694 : :
695 : : /*
696 : : * vm_normal_page -- This function gets the "struct page" associated with a pte.
697 : : *
698 : : * "Special" mappings do not wish to be associated with a "struct page" (either
699 : : * it doesn't exist, or it exists but they don't want to touch it). In this
700 : : * case, NULL is returned here. "Normal" mappings do have a struct page.
701 : : *
702 : : * There are 2 broad cases. Firstly, an architecture may define a pte_special()
703 : : * pte bit, in which case this function is trivial. Secondly, an architecture
704 : : * may not have a spare pte bit, which requires a more complicated scheme,
705 : : * described below.
706 : : *
707 : : * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
708 : : * special mapping (even if there are underlying and valid "struct pages").
709 : : * COWed pages of a VM_PFNMAP are always normal.
710 : : *
711 : : * The way we recognize COWed pages within VM_PFNMAP mappings is through the
712 : : * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
713 : : * set, and the vm_pgoff will point to the first PFN mapped: thus every special
714 : : * mapping will always honor the rule
715 : : *
716 : : * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
717 : : *
718 : : * And for normal mappings this is false.
719 : : *
720 : : * This restricts such mappings to be a linear translation from virtual address
721 : : * to pfn. To get around this restriction, we allow arbitrary mappings so long
722 : : * as the vma is not a COW mapping; in that case, we know that all ptes are
723 : : * special (because none can have been COWed).
724 : : *
725 : : *
726 : : * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
727 : : *
728 : : * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
729 : : * page" backing, however the difference is that _all_ pages with a struct
730 : : * page (that is, those where pfn_valid is true) are refcounted and considered
731 : : * normal pages by the VM. The disadvantage is that pages are refcounted
732 : : * (which can be slower and simply not an option for some PFNMAP users). The
733 : : * advantage is that we don't have to follow the strict linearity rule of
734 : : * PFNMAP mappings in order to support COWable mappings.
735 : : *
736 : : */
737 : : #ifdef __HAVE_ARCH_PTE_SPECIAL
738 : : # define HAVE_PTE_SPECIAL 1
739 : : #else
740 : : # define HAVE_PTE_SPECIAL 0
741 : : #endif
742 : 0 : struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
743 : : pte_t pte)
744 : : {
745 : 131691453 : unsigned long pfn = pte_pfn(pte);
746 : :
747 : : if (HAVE_PTE_SPECIAL) {
748 : : if (likely(!pte_special(pte)))
749 : : goto check_pfn;
750 : : if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
751 : : return NULL;
752 : : if (!is_zero_pfn(pfn))
753 : : print_bad_pte(vma, addr, pte, NULL);
754 : : return NULL;
755 : : }
756 : :
757 : : /* !HAVE_PTE_SPECIAL case follows: */
758 : :
759 [ - + ]: 131691453 : if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
760 [ # # ]: 0 : if (vma->vm_flags & VM_MIXEDMAP) {
761 [ # # ]: 0 : if (!pfn_valid(pfn))
762 : : return NULL;
763 : : goto out;
764 : : } else {
765 : : unsigned long off;
766 : 0 : off = (addr - vma->vm_start) >> PAGE_SHIFT;
767 [ # # ]: 0 : if (pfn == vma->vm_pgoff + off)
768 : : return NULL;
769 [ # # ]: 0 : if (!is_cow_mapping(vma->vm_flags))
770 : : return NULL;
771 : : }
772 : : }
773 : :
774 [ + + ]: 131683443 : if (is_zero_pfn(pfn))
775 : : return NULL;
776 : : check_pfn:
777 [ - + ]: 131393623 : if (unlikely(pfn > highest_memmap_pfn)) {
778 : 0 : print_bad_pte(vma, addr, pte, NULL);
779 : 0 : return NULL;
780 : : }
781 : :
782 : : /*
783 : : * NOTE! We still have PageReserved() pages in the page tables.
784 : : * eg. VDSO mappings can cause them to exist.
785 : : */
786 : : out:
787 : 131397819 : return pfn_to_page(pfn);
788 : : }
789 : :
790 : : /*
791 : : * copy one vm_area from one task to the other. Assumes the page tables
792 : : * already present in the new task to be cleared in the whole range
793 : : * covered by this vma.
794 : : */
795 : :
796 : : static inline unsigned long
797 : : copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
798 : : pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
799 : : unsigned long addr, int *rss)
800 : : {
801 : 26690732 : unsigned long vm_flags = vma->vm_flags;
802 : : pte_t pte = *src_pte;
803 : 26689928 : struct page *page;
804 : :
805 : : /* pte contains position in swap or file, so copy. */
806 [ - + ]: 26690732 : if (unlikely(!pte_present(pte))) {
807 [ # # ]: 0 : if (!pte_file(pte)) {
808 : : swp_entry_t entry = pte_to_swp_entry(pte);
809 : :
810 [ # # ]: 0 : if (swap_duplicate(entry) < 0)
811 : : return entry.val;
812 : :
813 : : /* make sure dst_mm is on swapoff's mmlist. */
814 [ # # ]: 0 : if (unlikely(list_empty(&dst_mm->mmlist))) {
815 : : spin_lock(&mmlist_lock);
816 [ # # ]: 0 : if (list_empty(&dst_mm->mmlist))
817 : 0 : list_add(&dst_mm->mmlist,
818 : : &src_mm->mmlist);
819 : : spin_unlock(&mmlist_lock);
820 : : }
821 [ # # ]: 0 : if (likely(!non_swap_entry(entry)))
822 : 0 : rss[MM_SWAPENTS]++;
823 [ # # ]: 0 : else if (is_migration_entry(entry)) {
824 : : page = migration_entry_to_page(entry);
825 : :
826 [ # # ]: 0 : if (PageAnon(page))
827 : 0 : rss[MM_ANONPAGES]++;
828 : : else
829 : 0 : rss[MM_FILEPAGES]++;
830 : :
831 [ # # ][ # # ]: 0 : if (is_write_migration_entry(entry) &&
832 : : is_cow_mapping(vm_flags)) {
833 : : /*
834 : : * COW mappings require pages in both
835 : : * parent and child to be set to read.
836 : : */
837 : : make_migration_entry_read(&entry);
838 : : pte = swp_entry_to_pte(entry);
839 : : if (pte_swp_soft_dirty(*src_pte))
840 : : pte = pte_swp_mksoft_dirty(pte);
841 : : set_pte_at(src_mm, addr, src_pte, pte);
842 : : }
843 : : }
844 : : }
845 : : goto out_set_pte;
846 : : }
847 : :
848 : : /*
849 : : * If it's a COW mapping, write protect it both
850 : : * in the parent and the child
851 : : */
852 [ + + ]: 26690732 : if (is_cow_mapping(vm_flags)) {
853 : : ptep_set_wrprotect(src_mm, addr, src_pte);
854 : : pte = pte_wrprotect(pte);
855 : : }
856 : :
857 : : /*
858 : : * If it's a shared mapping, mark it clean in
859 : : * the child
860 : : */
861 [ - + ]: 26690937 : if (vm_flags & VM_SHARED)
862 : : pte = pte_mkclean(pte);
863 : : pte = pte_mkold(pte);
864 : :
865 : 26690937 : page = vm_normal_page(vma, addr, pte);
866 [ + + ]: 26690656 : if (page) {
867 : : get_page(page);
868 : : page_dup_rmap(page);
869 [ + + ]: 26689928 : if (PageAnon(page))
870 : 26689854 : rss[MM_ANONPAGES]++;
871 : : else
872 : 74 : rss[MM_FILEPAGES]++;
873 : : }
874 : :
875 : : out_set_pte:
876 : : set_pte_at(dst_mm, addr, dst_pte, pte);
877 : : return 0;
878 : : }
879 : :
880 : 12739923 : int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
881 : 25480796 : pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
882 : : unsigned long addr, unsigned long end)
883 : : {
884 : : pte_t *orig_src_pte, *orig_dst_pte;
885 : : pte_t *src_pte, *dst_pte;
886 : : spinlock_t *src_ptl, *dst_ptl;
887 : : int progress = 0;
888 : : int rss[NR_MM_COUNTERS];
889 : : swp_entry_t entry = (swp_entry_t){0};
890 : :
891 : : again:
892 : : init_rss_vec(rss);
893 : :
894 [ + + ][ + - ]: 25480789 : dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
895 [ + - ]: 12740398 : if (!dst_pte)
896 : : return -ENOMEM;
897 : 12740398 : src_pte = pte_offset_map(src_pmd, addr);
898 : : src_ptl = pte_lockptr(src_mm, src_pmd);
899 : 12740397 : spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
900 : : orig_src_pte = src_pte;
901 : : orig_dst_pte = dst_pte;
902 : : arch_enter_lazy_mmu_mode();
903 : :
904 : : do {
905 : : /*
906 : : * We are holding two locks at this point - either of them
907 : : * could generate latencies in another task on another CPU.
908 : : */
909 [ + + ]: 125682724 : if (progress >= 32) {
910 : : progress = 0;
911 [ + + ]: 4657994 : if (need_resched() ||
912 : : spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
913 : : break;
914 : : }
915 [ + + ]: 125682256 : if (pte_none(*src_pte)) {
916 : 98991524 : progress++;
917 : 98991524 : continue;
918 : : }
919 : : entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
920 : : vma, addr, rss);
921 [ + - ]: 26690818 : if (entry.val)
922 : : break;
923 : 26690818 : progress += 8;
924 [ + + ]: 125682342 : } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
925 : :
926 : : arch_leave_lazy_mmu_mode();
927 : : spin_unlock(src_ptl);
928 : 12740390 : pte_unmap(orig_src_pte);
929 : : add_mm_rss_vec(dst_mm, rss);
930 : 12740392 : pte_unmap_unlock(orig_dst_pte, dst_ptl);
931 : 12740399 : cond_resched();
932 : :
933 [ - + ]: 12740387 : if (entry.val) {
934 [ # # ]: 0 : if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
935 : : return -ENOMEM;
936 : : progress = 0;
937 : : }
938 [ + + ]: 12740391 : if (addr != end)
939 : : goto again;
940 : : return 0;
941 : : }
942 : :
943 : : static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
944 : : pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
945 : : unsigned long addr, unsigned long end)
946 : : {
947 : : pmd_t *src_pmd, *dst_pmd;
948 : : unsigned long next;
949 : :
950 : : dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
951 [ + ]: 12760305 : if (!dst_pmd)
952 : : return -ENOMEM;
953 : : src_pmd = pmd_offset(src_pud, addr);
954 : : do {
955 : : next = pmd_addr_end(addr, end);
956 : : if (pmd_trans_huge(*src_pmd)) {
957 : : int err;
958 : : VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
959 : : err = copy_huge_pmd(dst_mm, src_mm,
960 : : dst_pmd, src_pmd, addr, vma);
961 : : if (err == -ENOMEM)
962 : : return -ENOMEM;
963 : : if (!err)
964 : : continue;
965 : : /* fall through */
966 : : }
967 [ + + ]: 12760296 : if (pmd_none_or_clear_bad(src_pmd))
968 : 20387 : continue;
969 [ + ]: 12739909 : if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
970 : : vma, addr, next))
971 : : return -ENOMEM;
972 : : } while (dst_pmd++, src_pmd++, addr = next, addr != end);
973 : : return 0;
974 : : }
975 : :
976 : : static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
977 : : pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
978 : : unsigned long addr, unsigned long end)
979 : : {
980 : : pud_t *src_pud, *dst_pud;
981 : : unsigned long next;
982 : :
983 : : dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
984 [ + + ]: 12760313 : if (!dst_pud)
985 : : return -ENOMEM;
986 : : src_pud = pud_offset(src_pgd, addr);
987 : : do {
988 : : next = pud_addr_end(addr, end);
989 : : if (pud_none_or_clear_bad(src_pud))
990 : : continue;
991 [ + ]: 12760311 : if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
992 : : vma, addr, next))
993 : : return -ENOMEM;
994 : : } while (dst_pud++, src_pud++, addr = next, addr != end);
995 : : return 0;
996 : : }
997 : :
998 : 0 : int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
999 : : struct vm_area_struct *vma)
1000 : : {
1001 : : pgd_t *src_pgd, *dst_pgd;
1002 : : unsigned long next;
1003 : 19102925 : unsigned long addr = vma->vm_start;
1004 : 19102925 : unsigned long end = vma->vm_end;
1005 : : unsigned long mmun_start; /* For mmu_notifiers */
1006 : : unsigned long mmun_end; /* For mmu_notifiers */
1007 : : bool is_cow;
1008 : : int ret;
1009 : :
1010 : : /*
1011 : : * Don't copy ptes where a page fault will fill them correctly.
1012 : : * Fork becomes much lighter when there are big shared or private
1013 : : * readonly mappings. The tradeoff is that copy_page_range is more
1014 : : * efficient than faulting.
1015 : : */
1016 [ + ]: 19102925 : if (!(vma->vm_flags & (VM_HUGETLB | VM_NONLINEAR |
1017 : : VM_PFNMAP | VM_MIXEDMAP))) {
1018 [ + ]: 19102938 : if (!vma->anon_vma)
1019 : : return 0;
1020 : : }
1021 : :
1022 : : if (is_vm_hugetlb_page(vma))
1023 : : return copy_hugetlb_page_range(dst_mm, src_mm, vma);
1024 : :
1025 : : if (unlikely(vma->vm_flags & VM_PFNMAP)) {
1026 : : /*
1027 : : * We do not free on error cases below as remove_vma
1028 : : * gets called on error from higher level routine
1029 : : */
1030 : : ret = track_pfn_copy(vma);
1031 : : if (ret)
1032 : : return ret;
1033 : : }
1034 : :
1035 : : /*
1036 : : * We need to invalidate the secondary MMU mappings only when
1037 : : * there could be a permission downgrade on the ptes of the
1038 : : * parent mm. And a permission downgrade will only happen if
1039 : : * is_cow_mapping() returns true.
1040 : : */
1041 : : is_cow = is_cow_mapping(vma->vm_flags);
1042 : : mmun_start = addr;
1043 : : mmun_end = end;
1044 : : if (is_cow)
1045 : : mmu_notifier_invalidate_range_start(src_mm, mmun_start,
1046 : : mmun_end);
1047 : :
1048 : : ret = 0;
1049 : 31799038 : dst_pgd = pgd_offset(dst_mm, addr);
1050 : 31799038 : src_pgd = pgd_offset(src_mm, addr);
1051 : : do {
1052 [ + + ]: 31863238 : next = pgd_addr_end(addr, end);
1053 : : if (pgd_none_or_clear_bad(src_pgd))
1054 : : continue;
1055 [ + + ]: 12760319 : if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
1056 : : vma, addr, next))) {
1057 : : ret = -ENOMEM;
1058 : : break;
1059 : : }
1060 [ + + ]: 12760318 : } while (dst_pgd++, src_pgd++, addr = next, addr != end);
1061 : :
1062 : : if (is_cow)
1063 : : mmu_notifier_invalidate_range_end(src_mm, mmun_start, mmun_end);
1064 : 12696119 : return ret;
1065 : : }
1066 : :
1067 : 0 : static unsigned long zap_pte_range(struct mmu_gather *tlb,
1068 : 22541564 : struct vm_area_struct *vma, pmd_t *pmd,
1069 : : unsigned long addr, unsigned long end,
1070 : : struct zap_details *details)
1071 : : {
1072 : 22523914 : struct mm_struct *mm = tlb->mm;
1073 : : int force_flush = 0;
1074 : : int rss[NR_MM_COUNTERS];
1075 : : spinlock_t *ptl;
1076 : : pte_t *start_pte;
1077 : : pte_t *pte;
1078 : :
1079 : : again:
1080 : : init_rss_vec(rss);
1081 : 22541564 : start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
1082 : : pte = start_pte;
1083 : : arch_enter_lazy_mmu_mode();
1084 : : do {
1085 : 529054963 : pte_t ptent = *pte;
1086 [ + + ]: 529054963 : if (pte_none(ptent)) {
1087 : 422602882 : continue;
1088 : : }
1089 : :
1090 [ + - ]: 106452081 : if (pte_present(ptent)) {
1091 : 83893936 : struct page *page;
1092 : :
1093 : 83928167 : page = vm_normal_page(vma, addr, ptent);
1094 [ - + ][ # # ]: 83928861 : if (unlikely(details) && page) {
1095 : : /*
1096 : : * unmap_shared_mapping_pages() wants to
1097 : : * invalidate cache without truncating:
1098 : : * unmap shared but keep private pages.
1099 : : */
1100 [ # # ][ # # ]: 0 : if (details->check_mapping &&
1101 : 0 : details->check_mapping != page->mapping)
1102 : 0 : continue;
1103 : : /*
1104 : : * Each page->index must be checked when
1105 : : * invalidating or truncating nonlinear.
1106 : : */
1107 [ # # ][ # # ]: 0 : if (details->nonlinear_vma &&
1108 [ # # ]: 0 : (page->index < details->first_index ||
1109 : 0 : page->index > details->last_index))
1110 : 0 : continue;
1111 : : }
1112 : : ptent = ptep_get_and_clear_full(mm, addr, pte,
1113 : : tlb->fullmm);
1114 : : tlb_remove_tlb_entry(tlb, pte, addr);
1115 [ + + ]: 83934932 : if (unlikely(!page))
1116 : 35954 : continue;
1117 [ - + ][ # # ]: 83898978 : if (unlikely(details) && details->nonlinear_vma
1118 [ # # ]: 0 : && linear_page_index(details->nonlinear_vma,
1119 : 0 : addr) != page->index) {
1120 : 0 : pte_t ptfile = pgoff_to_pte(page->index);
1121 : : if (pte_soft_dirty(ptent))
1122 : : pte_file_mksoft_dirty(ptfile);
1123 : : set_pte_at(mm, addr, pte, ptfile);
1124 : : }
1125 [ + + ]: 83893936 : if (PageAnon(page))
1126 : 43609023 : rss[MM_ANONPAGES]--;
1127 : : else {
1128 [ + + ]: 40284913 : if (pte_dirty(ptent))
1129 : 393185 : set_page_dirty(page);
1130 [ + + ][ + ]: 40291006 : if (pte_young(ptent) &&
1131 : 40287201 : likely(!(vma->vm_flags & VM_SEQ_READ)))
1132 : 40287515 : mark_page_accessed(page);
1133 : 40293607 : rss[MM_FILEPAGES]--;
1134 : : }
1135 : 83902630 : page_remove_rmap(page);
1136 [ - + ]: 83905141 : if (unlikely(page_mapcount(page) < 0))
1137 : 0 : print_bad_pte(vma, addr, ptent, page);
1138 : 83901292 : force_flush = !__tlb_remove_page(tlb, page);
1139 [ + + ]: 83901292 : if (force_flush)
1140 : : break;
1141 : 83883722 : continue;
1142 : : }
1143 : : /*
1144 : : * If details->check_mapping, we leave swap entries;
1145 : : * if details->nonlinear_vma, we leave file entries.
1146 : : */
1147 [ # # ]: 0 : if (unlikely(details))
1148 : 0 : continue;
1149 [ # # ]: 0 : if (pte_file(ptent)) {
1150 [ # # ]: 0 : if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
1151 : 0 : print_bad_pte(vma, addr, ptent, NULL);
1152 : : } else {
1153 : : swp_entry_t entry = pte_to_swp_entry(ptent);
1154 : :
1155 [ # # ]: 0 : if (!non_swap_entry(entry))
1156 : 0 : rss[MM_SWAPENTS]--;
1157 [ # # ]: 0 : else if (is_migration_entry(entry)) {
1158 : 0 : struct page *page;
1159 : :
1160 : : page = migration_entry_to_page(entry);
1161 : :
1162 [ # # ]: 0 : if (PageAnon(page))
1163 : 0 : rss[MM_ANONPAGES]--;
1164 : : else
1165 : 0 : rss[MM_FILEPAGES]--;
1166 : : }
1167 [ # # ]: 0 : if (unlikely(!free_swap_and_cache(entry)))
1168 : 0 : print_bad_pte(vma, addr, ptent, NULL);
1169 : : }
1170 : : pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
1171 [ + + ]: 506487988 : } while (pte++, addr += PAGE_SIZE, addr != end);
1172 : :
1173 : : add_mm_rss_vec(mm, rss);
1174 : : arch_leave_lazy_mmu_mode();
1175 : 22540973 : pte_unmap_unlock(start_pte, ptl);
1176 : :
1177 : : /*
1178 : : * mmu_gather ran out of room to batch pages, we break out of
1179 : : * the PTE lock to avoid doing the potential expensive TLB invalidate
1180 : : * and page-free while holding it.
1181 : : */
1182 [ + + ]: 22541797 : if (force_flush) {
1183 : : unsigned long old_end;
1184 : :
1185 : : force_flush = 0;
1186 : :
1187 : : /*
1188 : : * Flush the TLB just for the previous segment,
1189 : : * then update the range to be the remaining
1190 : : * TLB range.
1191 : : */
1192 : 17614 : old_end = tlb->end;
1193 : 17614 : tlb->end = addr;
1194 : :
1195 : : tlb_flush_mmu(tlb);
1196 : :
1197 : 17614 : tlb->start = addr;
1198 : 17614 : tlb->end = old_end;
1199 : :
1200 [ + - ]: 17614 : if (addr != end)
1201 : : goto again;
1202 : : }
1203 : :
1204 : 22524183 : return addr;
1205 : : }
1206 : :
1207 : : static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
1208 : : struct vm_area_struct *vma, pud_t *pud,
1209 : : unsigned long addr, unsigned long end,
1210 : : struct zap_details *details)
1211 : : {
1212 : : pmd_t *pmd;
1213 : : unsigned long next;
1214 : :
1215 : : pmd = pmd_offset(pud, addr);
1216 : : do {
1217 : : next = pmd_addr_end(addr, end);
1218 : : if (pmd_trans_huge(*pmd)) {
1219 : : if (next - addr != HPAGE_PMD_SIZE) {
1220 : : #ifdef CONFIG_DEBUG_VM
1221 : : if (!rwsem_is_locked(&tlb->mm->mmap_sem)) {
1222 : : pr_err("%s: mmap_sem is unlocked! addr=0x%lx end=0x%lx vma->vm_start=0x%lx vma->vm_end=0x%lx\n",
1223 : : __func__, addr, end,
1224 : : vma->vm_start,
1225 : : vma->vm_end);
1226 : : BUG();
1227 : : }
1228 : : #endif
1229 : : split_huge_page_pmd(vma, addr, pmd);
1230 : : } else if (zap_huge_pmd(tlb, vma, pmd, addr))
1231 : : goto next;
1232 : : /* fall through */
1233 : : }
1234 : : /*
1235 : : * Here there can be other concurrent MADV_DONTNEED or
1236 : : * trans huge page faults running, and if the pmd is
1237 : : * none or trans huge it can change under us. This is
1238 : : * because MADV_DONTNEED holds the mmap_sem in read
1239 : : * mode.
1240 : : */
1241 [ + + ]: 23661821 : if (pmd_none_or_trans_huge_or_clear_bad(pmd))
1242 : : goto next;
1243 : 22523717 : next = zap_pte_range(tlb, vma, pmd, addr, next, details);
1244 : : next:
1245 : 23662033 : cond_resched();
1246 [ + + ]: 23662223 : } while (pmd++, addr = next, addr != end);
1247 : :
1248 : : return addr;
1249 : : }
1250 : :
1251 : : static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1252 : : struct vm_area_struct *vma, pgd_t *pgd,
1253 : : unsigned long addr, unsigned long end,
1254 : : struct zap_details *details)
1255 : : {
1256 : : pud_t *pud;
1257 : : unsigned long next;
1258 : :
1259 : : pud = pud_offset(pgd, addr);
1260 : : do {
1261 : : next = pud_addr_end(addr, end);
1262 : : if (pud_none_or_clear_bad(pud))
1263 : : continue;
1264 : : next = zap_pmd_range(tlb, vma, pud, addr, next, details);
1265 [ + ]: 23662194 : } while (pud++, addr = next, addr != end);
1266 : :
1267 : : return addr;
1268 : : }
1269 : :
1270 : 0 : static void unmap_page_range(struct mmu_gather *tlb,
1271 : : struct vm_area_struct *vma,
1272 : : unsigned long addr, unsigned long end,
1273 : : struct zap_details *details)
1274 : : {
1275 : : pgd_t *pgd;
1276 : : unsigned long next;
1277 : :
1278 [ + + ][ + + ]: 23301591 : if (details && !details->check_mapping && !details->nonlinear_vma)
[ + - ]
1279 : : details = NULL;
1280 : :
1281 [ - + ]: 23301591 : BUG_ON(addr >= end);
1282 : : mem_cgroup_uncharge_start();
1283 : : tlb_start_vma(tlb, vma);
1284 : 23301557 : pgd = pgd_offset(vma->vm_mm, addr);
1285 : : do {
1286 [ + + ]: 23661822 : next = pgd_addr_end(addr, end);
1287 : : if (pgd_none_or_clear_bad(pgd))
1288 : : continue;
1289 : : next = zap_pud_range(tlb, vma, pgd, addr, next, details);
1290 [ + + ]: 23662237 : } while (pgd++, addr = next, addr != end);
1291 : : tlb_end_vma(tlb, vma);
1292 : : mem_cgroup_uncharge_end();
1293 : 23301934 : }
1294 : :
1295 : :
1296 : 0 : static void unmap_single_vma(struct mmu_gather *tlb,
1297 : : struct vm_area_struct *vma, unsigned long start_addr,
1298 : : unsigned long end_addr,
1299 : : struct zap_details *details)
1300 : : {
1301 : 23301600 : unsigned long start = max(vma->vm_start, start_addr);
1302 : : unsigned long end;
1303 : :
1304 [ + ]: 23301600 : if (start >= vma->vm_end)
1305 : : return;
1306 : 23301602 : end = min(vma->vm_end, end_addr);
1307 [ + ]: 23301602 : if (end <= vma->vm_start)
1308 : : return;
1309 : :
1310 : : if (vma->vm_file)
1311 : : uprobe_munmap(vma, start, end);
1312 : :
1313 : : if (unlikely(vma->vm_flags & VM_PFNMAP))
1314 : : untrack_pfn(vma, 0, 0);
1315 : :
1316 [ + ]: 23301725 : if (start != end) {
1317 : : if (unlikely(is_vm_hugetlb_page(vma))) {
1318 : : /*
1319 : : * It is undesirable to test vma->vm_file as it
1320 : : * should be non-null for valid hugetlb area.
1321 : : * However, vm_file will be NULL in the error
1322 : : * cleanup path of do_mmap_pgoff. When
1323 : : * hugetlbfs ->mmap method fails,
1324 : : * do_mmap_pgoff() nullifies vma->vm_file
1325 : : * before calling this function to clean up.
1326 : : * Since no pte has actually been setup, it is
1327 : : * safe to do nothing in this case.
1328 : : */
1329 : : if (vma->vm_file) {
1330 : : mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
1331 : : __unmap_hugepage_range_final(tlb, vma, start, end, NULL);
1332 : : mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
1333 : : }
1334 : : } else
1335 : 23301729 : unmap_page_range(tlb, vma, start, end, details);
1336 : : }
1337 : : }
1338 : :
1339 : : /**
1340 : : * unmap_vmas - unmap a range of memory covered by a list of vma's
1341 : : * @tlb: address of the caller's struct mmu_gather
1342 : : * @vma: the starting vma
1343 : : * @start_addr: virtual address at which to start unmapping
1344 : : * @end_addr: virtual address at which to end unmapping
1345 : : *
1346 : : * Unmap all pages in the vma list.
1347 : : *
1348 : : * Only addresses between `start' and `end' will be unmapped.
1349 : : *
1350 : : * The VMA list must be sorted in ascending virtual address order.
1351 : : *
1352 : : * unmap_vmas() assumes that the caller will flush the whole unmapped address
1353 : : * range after unmap_vmas() returns. So the only responsibility here is to
1354 : : * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1355 : : * drops the lock and schedules.
1356 : : */
1357 : 2375771 : void unmap_vmas(struct mmu_gather *tlb,
1358 : : struct vm_area_struct *vma, unsigned long start_addr,
1359 : : unsigned long end_addr)
1360 : : {
1361 : : struct mm_struct *mm = vma->vm_mm;
1362 : :
1363 : : mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
1364 [ + + ][ + + ]: 25672623 : for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
1365 : 23296521 : unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
1366 : : mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
1367 : 331 : }
1368 : :
1369 : : /**
1370 : : * zap_page_range - remove user pages in a given range
1371 : : * @vma: vm_area_struct holding the applicable pages
1372 : : * @start: starting address of pages to zap
1373 : : * @size: number of bytes to zap
1374 : : * @details: details of nonlinear truncation or shared cache invalidation
1375 : : *
1376 : : * Caller must protect the VMA list
1377 : : */
1378 : 0 : void zap_page_range(struct vm_area_struct *vma, unsigned long start,
1379 : : unsigned long size, struct zap_details *details)
1380 : : {
1381 : 4875 : struct mm_struct *mm = vma->vm_mm;
1382 : : struct mmu_gather tlb;
1383 : 4875 : unsigned long end = start + size;
1384 : :
1385 : 4875 : lru_add_drain();
1386 : : tlb_gather_mmu(&tlb, mm, start, end);
1387 : : update_hiwater_rss(mm);
1388 : : mmu_notifier_invalidate_range_start(mm, start, end);
1389 [ + + ][ + + ]: 9750 : for ( ; vma && vma->vm_start < end; vma = vma->vm_next)
1390 : 4875 : unmap_single_vma(&tlb, vma, start, end, details);
1391 : : mmu_notifier_invalidate_range_end(mm, start, end);
1392 : : tlb_finish_mmu(&tlb, start, end);
1393 : 4875 : }
1394 : :
1395 : : /**
1396 : : * zap_page_range_single - remove user pages in a given range
1397 : : * @vma: vm_area_struct holding the applicable pages
1398 : : * @address: starting address of pages to zap
1399 : : * @size: number of bytes to zap
1400 : : * @details: details of nonlinear truncation or shared cache invalidation
1401 : : *
1402 : : * The range must fit into one VMA.
1403 : : */
1404 : 0 : static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
1405 : : unsigned long size, struct zap_details *details)
1406 : : {
1407 : 5 : struct mm_struct *mm = vma->vm_mm;
1408 : : struct mmu_gather tlb;
1409 : 5 : unsigned long end = address + size;
1410 : :
1411 : 5 : lru_add_drain();
1412 : : tlb_gather_mmu(&tlb, mm, address, end);
1413 : : update_hiwater_rss(mm);
1414 : : mmu_notifier_invalidate_range_start(mm, address, end);
1415 : 5 : unmap_single_vma(&tlb, vma, address, end, details);
1416 : : mmu_notifier_invalidate_range_end(mm, address, end);
1417 : : tlb_finish_mmu(&tlb, address, end);
1418 : 5 : }
1419 : :
1420 : : /**
1421 : : * zap_vma_ptes - remove ptes mapping the vma
1422 : : * @vma: vm_area_struct holding ptes to be zapped
1423 : : * @address: starting address of pages to zap
1424 : : * @size: number of bytes to zap
1425 : : *
1426 : : * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1427 : : *
1428 : : * The entire address range must be fully contained within the vma.
1429 : : *
1430 : : * Returns 0 if successful.
1431 : : */
1432 : 0 : int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1433 : : unsigned long size)
1434 : : {
1435 [ # # ][ # # ]: 0 : if (address < vma->vm_start || address + size > vma->vm_end ||
[ # # ]
1436 : 0 : !(vma->vm_flags & VM_PFNMAP))
1437 : : return -1;
1438 : 0 : zap_page_range_single(vma, address, size, NULL);
1439 : 0 : return 0;
1440 : : }
1441 : : EXPORT_SYMBOL_GPL(zap_vma_ptes);
1442 : :
1443 : : /**
1444 : : * follow_page_mask - look up a page descriptor from a user-virtual address
1445 : : * @vma: vm_area_struct mapping @address
1446 : : * @address: virtual address to look up
1447 : : * @flags: flags modifying lookup behaviour
1448 : : * @page_mask: on output, *page_mask is set according to the size of the page
1449 : : *
1450 : : * @flags can have FOLL_ flags set, defined in <linux/mm.h>
1451 : : *
1452 : : * Returns the mapped (struct page *), %NULL if no mapping exists, or
1453 : : * an error pointer if there is a mapping to something not represented
1454 : : * by a page descriptor (see also vm_normal_page()).
1455 : : */
1456 : 0 : struct page *follow_page_mask(struct vm_area_struct *vma,
1457 : : unsigned long address, unsigned int flags,
1458 : : unsigned int *page_mask)
1459 : : {
1460 : : pgd_t *pgd;
1461 : : pud_t *pud;
1462 : : pmd_t *pmd;
1463 : : pte_t *ptep, pte;
1464 : : spinlock_t *ptl;
1465 : : struct page *page;
1466 : 4653431 : struct mm_struct *mm = vma->vm_mm;
1467 : :
1468 : 4653431 : *page_mask = 0;
1469 : :
1470 : : page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1471 : : if (!IS_ERR(page)) {
1472 : : BUG_ON(flags & FOLL_GET);
1473 : : goto out;
1474 : : }
1475 : :
1476 : : page = NULL;
1477 : 4653431 : pgd = pgd_offset(mm, address);
1478 : : if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
1479 : : goto no_page_table;
1480 : :
1481 : : pud = pud_offset(pgd, address);
1482 : : if (pud_none(*pud))
1483 : : goto no_page_table;
1484 : : if (pud_huge(*pud) && vma->vm_flags & VM_HUGETLB) {
1485 : : if (flags & FOLL_GET)
1486 : : goto out;
1487 : : page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1488 : : goto out;
1489 : : }
1490 : : if (unlikely(pud_bad(*pud)))
1491 : : goto no_page_table;
1492 : :
1493 : : pmd = pmd_offset(pud, address);
1494 [ + + ]: 4653431 : if (pmd_none(*pmd))
1495 : : goto no_page_table;
1496 : : if (pmd_huge(*pmd) && vma->vm_flags & VM_HUGETLB) {
1497 : : page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1498 : : if (flags & FOLL_GET) {
1499 : : /*
1500 : : * Refcount on tail pages are not well-defined and
1501 : : * shouldn't be taken. The caller should handle a NULL
1502 : : * return when trying to follow tail pages.
1503 : : */
1504 : : if (PageHead(page))
1505 : : get_page(page);
1506 : : else {
1507 : : page = NULL;
1508 : : goto out;
1509 : : }
1510 : : }
1511 : : goto out;
1512 : : }
1513 : : if ((flags & FOLL_NUMA) && pmd_numa(*pmd))
1514 : : goto no_page_table;
1515 : : if (pmd_trans_huge(*pmd)) {
1516 : : if (flags & FOLL_SPLIT) {
1517 : : split_huge_page_pmd(vma, address, pmd);
1518 : : goto split_fallthrough;
1519 : : }
1520 : : ptl = pmd_lock(mm, pmd);
1521 : : if (likely(pmd_trans_huge(*pmd))) {
1522 : : if (unlikely(pmd_trans_splitting(*pmd))) {
1523 : : spin_unlock(ptl);
1524 : : wait_split_huge_page(vma->anon_vma, pmd);
1525 : : } else {
1526 : : page = follow_trans_huge_pmd(vma, address,
1527 : : pmd, flags);
1528 : : spin_unlock(ptl);
1529 : : *page_mask = HPAGE_PMD_NR - 1;
1530 : : goto out;
1531 : : }
1532 : : } else
1533 : : spin_unlock(ptl);
1534 : : /* fall through */
1535 : : }
1536 : : split_fallthrough:
1537 [ + + ]: 9244229 : if (unlikely(pmd_bad(*pmd)))
1538 : : goto no_page_table;
1539 : :
1540 : 4590797 : ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
1541 : :
1542 : 4590799 : pte = *ptep;
1543 [ + + ]: 4590799 : if (!pte_present(pte)) {
1544 : : swp_entry_t entry;
1545 : : /*
1546 : : * KSM's break_ksm() relies upon recognizing a ksm page
1547 : : * even while it is being migrated, so for that case we
1548 : : * need migration_entry_wait().
1549 : : */
1550 [ - + ]: 1974046 : if (likely(!(flags & FOLL_MIGRATION)))
1551 : : goto no_page;
1552 [ # # ][ # # ]: 0 : if (pte_none(pte) || pte_file(pte))
1553 : : goto no_page;
1554 : : entry = pte_to_swp_entry(pte);
1555 [ # # ]: 0 : if (!is_migration_entry(entry))
1556 : : goto no_page;
1557 : 0 : pte_unmap_unlock(ptep, ptl);
1558 : 0 : migration_entry_wait(mm, pmd, address);
1559 : : goto split_fallthrough;
1560 : : }
1561 : : if ((flags & FOLL_NUMA) && pte_numa(pte))
1562 : : goto no_page;
1563 [ + + ][ + + ]: 2616753 : if ((flags & FOLL_WRITE) && !pte_write(pte))
1564 : : goto unlock;
1565 : :
1566 : 2616751 : page = vm_normal_page(vma, address, pte);
1567 [ + + ]: 2616739 : if (unlikely(!page)) {
1568 [ + - ][ + - ]: 3 : if ((flags & FOLL_DUMP) ||
1569 : 3 : !is_zero_pfn(pte_pfn(pte)))
1570 : : goto bad_page;
1571 : 3 : page = pte_page(pte);
1572 : : }
1573 : :
1574 [ + + ]: 2616739 : if (flags & FOLL_GET)
1575 : : get_page_foll(page);
1576 [ + + ]: 2616721 : if (flags & FOLL_TOUCH) {
1577 [ + + ][ - + ]: 2615268 : if ((flags & FOLL_WRITE) &&
1578 [ # # ]: 0 : !pte_dirty(pte) && !PageDirty(page))
1579 : 0 : set_page_dirty(page);
1580 : : /*
1581 : : * pte_mkyoung() would be more correct here, but atomic care
1582 : : * is needed to avoid losing the dirty bit: it is easier to use
1583 : : * mark_page_accessed().
1584 : : */
1585 : 2615268 : mark_page_accessed(page);
1586 : : }
1587 [ + + ][ + + ]: 2616742 : if ((flags & FOLL_MLOCK) && (vma->vm_flags & VM_LOCKED)) {
1588 : : /*
1589 : : * The preliminary mapping check is mainly to avoid the
1590 : : * pointless overhead of lock_page on the ZERO_PAGE
1591 : : * which might bounce very badly if there is contention.
1592 : : *
1593 : : * If the page is already locked, we don't need to
1594 : : * handle it now - vmscan will handle it later if and
1595 : : * when it attempts to reclaim the page.
1596 : : */
1597 [ + - + - ]: 20812 : if (page->mapping && trylock_page(page)) {
1598 : 10406 : lru_add_drain(); /* push cached pages to LRU */
1599 : : /*
1600 : : * Because we lock page here, and migration is
1601 : : * blocked by the pte's page reference, and we
1602 : : * know the page is still mapped, we don't even
1603 : : * need to check for file-cache page truncation.
1604 : : */
1605 : 10406 : mlock_vma_page(page);
1606 : 10406 : unlock_page(page);
1607 : : }
1608 : : }
1609 : : unlock:
1610 : 2616745 : pte_unmap_unlock(ptep, ptl);
1611 : : out:
1612 : 2616756 : return page;
1613 : :
1614 : : bad_page:
1615 : 0 : pte_unmap_unlock(ptep, ptl);
1616 : 0 : return ERR_PTR(-EFAULT);
1617 : :
1618 : : no_page:
1619 : 1974046 : pte_unmap_unlock(ptep, ptl);
1620 [ + + ]: 1974046 : if (!pte_none(pte))
1621 : : return page;
1622 : :
1623 : : no_page_table:
1624 : : /*
1625 : : * When core dumping an enormous anonymous area that nobody
1626 : : * has touched so far, we don't want to allocate unnecessary pages or
1627 : : * page tables. Return error instead of NULL to skip handle_mm_fault,
1628 : : * then get_dump_page() will return NULL to leave a hole in the dump.
1629 : : * But we can only make this optimization where a hole would surely
1630 : : * be zero-filled if handle_mm_fault() actually did handle it.
1631 : : */
1632 [ + + ][ + + ]: 2036646 : if ((flags & FOLL_DUMP) &&
1633 [ + - ]: 109 : (!vma->vm_ops || !vma->vm_ops->fault))
1634 : : return ERR_PTR(-EFAULT);
1635 : 2035499 : return page;
1636 : : }
1637 : :
1638 : : static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
1639 : : {
1640 [ + + ]: 57689 : return stack_guard_page_start(vma, addr) ||
1641 : : stack_guard_page_end(vma, addr+PAGE_SIZE);
1642 : : }
1643 : :
1644 : : /**
1645 : : * __get_user_pages() - pin user pages in memory
1646 : : * @tsk: task_struct of target task
1647 : : * @mm: mm_struct of target mm
1648 : : * @start: starting user address
1649 : : * @nr_pages: number of pages from start to pin
1650 : : * @gup_flags: flags modifying pin behaviour
1651 : : * @pages: array that receives pointers to the pages pinned.
1652 : : * Should be at least nr_pages long. Or NULL, if caller
1653 : : * only intends to ensure the pages are faulted in.
1654 : : * @vmas: array of pointers to vmas corresponding to each page.
1655 : : * Or NULL if the caller does not require them.
1656 : : * @nonblocking: whether waiting for disk IO or mmap_sem contention
1657 : : *
1658 : : * Returns number of pages pinned. This may be fewer than the number
1659 : : * requested. If nr_pages is 0 or negative, returns 0. If no pages
1660 : : * were pinned, returns -errno. Each page returned must be released
1661 : : * with a put_page() call when it is finished with. vmas will only
1662 : : * remain valid while mmap_sem is held.
1663 : : *
1664 : : * Must be called with mmap_sem held for read or write.
1665 : : *
1666 : : * __get_user_pages walks a process's page tables and takes a reference to
1667 : : * each struct page that each user address corresponds to at a given
1668 : : * instant. That is, it takes the page that would be accessed if a user
1669 : : * thread accesses the given user virtual address at that instant.
1670 : : *
1671 : : * This does not guarantee that the page exists in the user mappings when
1672 : : * __get_user_pages returns, and there may even be a completely different
1673 : : * page there in some cases (eg. if mmapped pagecache has been invalidated
1674 : : * and subsequently re faulted). However it does guarantee that the page
1675 : : * won't be freed completely. And mostly callers simply care that the page
1676 : : * contains data that was valid *at some point in time*. Typically, an IO
1677 : : * or similar operation cannot guarantee anything stronger anyway because
1678 : : * locks can't be held over the syscall boundary.
1679 : : *
1680 : : * If @gup_flags & FOLL_WRITE == 0, the page must not be written to. If
1681 : : * the page is written to, set_page_dirty (or set_page_dirty_lock, as
1682 : : * appropriate) must be called after the page is finished with, and
1683 : : * before put_page is called.
1684 : : *
1685 : : * If @nonblocking != NULL, __get_user_pages will not wait for disk IO
1686 : : * or mmap_sem contention, and if waiting is needed to pin all pages,
1687 : : * *@nonblocking will be set to 0.
1688 : : *
1689 : : * In most cases, get_user_pages or get_user_pages_fast should be used
1690 : : * instead of __get_user_pages. __get_user_pages should be used only if
1691 : : * you need some special @gup_flags.
1692 : : */
1693 : 0 : long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1694 : : unsigned long start, unsigned long nr_pages,
1695 : : unsigned int gup_flags, struct page **pages,
1696 : : struct vm_area_struct **vmas, int *nonblocking)
1697 : : {
1698 : : long i;
1699 : : unsigned long vm_flags;
1700 : : unsigned int page_mask;
1701 : :
1702 [ + - ]: 2467766 : if (!nr_pages)
1703 : : return 0;
1704 : :
1705 : : VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1706 : :
1707 : : /*
1708 : : * Require read or write permissions.
1709 : : * If FOLL_FORCE is set, we only require the "MAY" flags.
1710 : : */
1711 [ + + ]: 2467766 : vm_flags = (gup_flags & FOLL_WRITE) ?
1712 : : (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1713 [ + + ]: 2467766 : vm_flags &= (gup_flags & FOLL_FORCE) ?
1714 : : (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1715 : :
1716 : : /*
1717 : : * If FOLL_FORCE and FOLL_NUMA are both set, handle_mm_fault
1718 : : * would be called on PROT_NONE ranges. We must never invoke
1719 : : * handle_mm_fault on PROT_NONE ranges or the NUMA hinting
1720 : : * page faults would unprotect the PROT_NONE ranges if
1721 : : * _PAGE_NUMA and _PAGE_PROTNONE are sharing the same pte/pmd
1722 : : * bitflag. So to avoid that, don't set FOLL_NUMA if
1723 : : * FOLL_FORCE is set.
1724 : : */
1725 [ + + ]: 2467766 : if (!(gup_flags & FOLL_FORCE))
1726 : 2467766 : gup_flags |= FOLL_NUMA;
1727 : :
1728 : : i = 0;
1729 : :
1730 : : do {
1731 : : struct vm_area_struct *vma;
1732 : :
1733 : 2467766 : vma = find_extend_vma(mm, start);
1734 [ + + ][ + + ]: 2467726 : if (!vma && in_gate_area(mm, start)) {
1735 : 18 : unsigned long pg = start & PAGE_MASK;
1736 : : pgd_t *pgd;
1737 : : pud_t *pud;
1738 : : pmd_t *pmd;
1739 : : pte_t *pte;
1740 : :
1741 : : /* user gate pages are read-only */
1742 [ - + ]: 18 : if (gup_flags & FOLL_WRITE)
1743 [ # # ]: 0 : return i ? : -EFAULT;
1744 [ + - ]: 18 : if (pg > TASK_SIZE)
1745 : 18 : pgd = pgd_offset_k(pg);
1746 : : else
1747 : 0 : pgd = pgd_offset_gate(mm, pg);
1748 : : BUG_ON(pgd_none(*pgd));
1749 : : pud = pud_offset(pgd, pg);
1750 : : BUG_ON(pud_none(*pud));
1751 : : pmd = pmd_offset(pud, pg);
1752 [ - + ]: 18 : if (pmd_none(*pmd))
1753 [ # # ]: 0 : return i ? : -EFAULT;
1754 : : VM_BUG_ON(pmd_trans_huge(*pmd));
1755 : 18 : pte = pte_offset_map(pmd, pg);
1756 [ - + ]: 18 : if (pte_none(*pte)) {
1757 : 0 : pte_unmap(pte);
1758 [ # # ]: 0 : return i ? : -EFAULT;
1759 : : }
1760 : 18 : vma = get_gate_vma(mm);
1761 [ + - ]: 18 : if (pages) {
1762 : : struct page *page;
1763 : :
1764 : 18 : page = vm_normal_page(vma, start, *pte);
1765 [ - + ]: 18 : if (!page) {
1766 [ # # ][ # # ]: 0 : if (!(gup_flags & FOLL_DUMP) &&
1767 : 0 : is_zero_pfn(pte_pfn(*pte)))
1768 : 0 : page = pte_page(*pte);
1769 : : else {
1770 : 0 : pte_unmap(pte);
1771 [ # # ]: 0 : return i ? : -EFAULT;
1772 : : }
1773 : : }
1774 : 18 : pages[i] = page;
1775 : : get_page(page);
1776 : : }
1777 : 18 : pte_unmap(pte);
1778 : 18 : page_mask = 0;
1779 : 18 : goto next_page;
1780 : : }
1781 : :
1782 [ + ][ + + ]: 2467708 : if (!vma ||
1783 [ + + ]: 2467744 : (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
1784 : 2467744 : !(vm_flags & vma->vm_flags))
1785 [ - + ]: 24 : return i ? : -EFAULT;
1786 : :
1787 : : if (is_vm_hugetlb_page(vma)) {
1788 : : i = follow_hugetlb_page(mm, vma, pages, vmas,
1789 : : &start, &nr_pages, i, gup_flags);
1790 : : continue;
1791 : : }
1792 : :
1793 : : do {
1794 : : struct page *page;
1795 : : unsigned int foll_flags = gup_flags;
1796 : : unsigned int page_increm;
1797 : :
1798 : : /*
1799 : : * If we have a pending SIGKILL, don't keep faulting
1800 : : * pages and potentially allocating memory.
1801 : : */
1802 [ - + ]: 2618235 : if (unlikely(fatal_signal_pending(current)))
1803 [ # # ]: 0 : return i ? i : -ERESTARTSYS;
1804 : :
1805 : 2618235 : cond_resched();
1806 [ + + ]: 4652180 : while (!(page = follow_page_mask(vma, start,
1807 : : foll_flags, &page_mask))) {
1808 : : int ret;
1809 : : unsigned int fault_flags = 0;
1810 : :
1811 : : /* For mlock, just skip the stack guard page. */
1812 [ + + ]: 2035443 : if (foll_flags & FOLL_MLOCK) {
1813 [ + + ]: 57689 : if (stack_guard_page(vma, start))
1814 : : goto next_page;
1815 : : }
1816 [ + ]: 2035389 : if (foll_flags & FOLL_WRITE)
1817 : : fault_flags |= FAULT_FLAG_WRITE;
1818 [ + ]: 0 : if (nonblocking)
1819 : 57686 : fault_flags |= FAULT_FLAG_ALLOW_RETRY;
1820 [ - ]: 0 : if (foll_flags & FOLL_NOWAIT)
1821 : 0 : fault_flags |= (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_RETRY_NOWAIT);
1822 : :
1823 : 0 : ret = handle_mm_fault(mm, vma, start,
1824 : : fault_flags);
1825 : :
1826 [ - + ]: 2035440 : if (ret & VM_FAULT_ERROR) {
1827 [ # # ]: 0 : if (ret & VM_FAULT_OOM)
1828 [ # # ]: 0 : return i ? i : -ENOMEM;
1829 [ # # ]: 0 : if (ret & (VM_FAULT_HWPOISON |
1830 : : VM_FAULT_HWPOISON_LARGE)) {
1831 [ # # ]: 0 : if (i)
1832 : : return i;
1833 [ # # ]: 0 : else if (gup_flags & FOLL_HWPOISON)
1834 : : return -EHWPOISON;
1835 : : else
1836 : 0 : return -EFAULT;
1837 : : }
1838 [ # # ]: 0 : if (ret & VM_FAULT_SIGBUS)
1839 [ # # ]: 0 : return i ? i : -EFAULT;
1840 : 0 : BUG();
1841 : : }
1842 : :
1843 [ + - ]: 2035440 : if (tsk) {
1844 [ + + ]: 2035440 : if (ret & VM_FAULT_MAJOR)
1845 : 9 : tsk->maj_flt++;
1846 : : else
1847 : 2035431 : tsk->min_flt++;
1848 : : }
1849 : :
1850 [ + + ]: 2035440 : if (ret & VM_FAULT_RETRY) {
1851 [ + - ]: 1421 : if (nonblocking)
1852 : 1421 : *nonblocking = 0;
1853 : 1421 : return i;
1854 : : }
1855 : :
1856 : : /*
1857 : : * The VM_FAULT_WRITE bit tells us that
1858 : : * do_wp_page has broken COW when necessary,
1859 : : * even if maybe_mkwrite decided not to set
1860 : : * pte_write. We can thus safely do subsequent
1861 : : * page lookups as if they were reads. But only
1862 : : * do so when looping for pte_write is futile:
1863 : : * in some cases userspace may also be wanting
1864 : : * to write to the gotten user page, which a
1865 : : * read fault here might prevent (a readonly
1866 : : * page might get reCOWed by userspace write).
1867 : : */
1868 [ + + ][ - + ]: 2034019 : if ((ret & VM_FAULT_WRITE) &&
1869 : 2 : !(vma->vm_flags & VM_WRITE))
1870 : 0 : foll_flags &= ~FOLL_WRITE;
1871 : :
1872 : 2034019 : cond_resched();
1873 : : }
1874 [ + + ]: 2616776 : if (IS_ERR(page))
1875 [ + - ]: 2290 : return i ? i : PTR_ERR(page);
1876 [ + + ]: 2615631 : if (pages) {
1877 : 2555761 : pages[i] = page;
1878 : :
1879 : : flush_anon_page(vma, page, start);
1880 : 2555802 : flush_dcache_page(page);
1881 : 2555744 : page_mask = 0;
1882 : : }
1883 : : next_page:
1884 [ + + ]: 2615686 : if (vmas) {
1885 : 455 : vmas[i] = vma;
1886 : 455 : page_mask = 0;
1887 : : }
1888 : 2615686 : page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
1889 [ - + ]: 2615686 : if (page_increm > nr_pages)
1890 : : page_increm = nr_pages;
1891 : 2615686 : i += page_increm;
1892 : 2615686 : start += page_increm * PAGE_SIZE;
1893 : 2615686 : nr_pages -= page_increm;
1894 [ + + ][ + ]: 2615686 : } while (nr_pages && start < vma->vm_end);
1895 [ - + ]: 2465135 : } while (nr_pages);
1896 : : return i;
1897 : : }
1898 : : EXPORT_SYMBOL(__get_user_pages);
1899 : :
1900 : : /*
1901 : : * fixup_user_fault() - manually resolve a user page fault
1902 : : * @tsk: the task_struct to use for page fault accounting, or
1903 : : * NULL if faults are not to be recorded.
1904 : : * @mm: mm_struct of target mm
1905 : : * @address: user address
1906 : : * @fault_flags:flags to pass down to handle_mm_fault()
1907 : : *
1908 : : * This is meant to be called in the specific scenario where for locking reasons
1909 : : * we try to access user memory in atomic context (within a pagefault_disable()
1910 : : * section), this returns -EFAULT, and we want to resolve the user fault before
1911 : : * trying again.
1912 : : *
1913 : : * Typically this is meant to be used by the futex code.
1914 : : *
1915 : : * The main difference with get_user_pages() is that this function will
1916 : : * unconditionally call handle_mm_fault() which will in turn perform all the
1917 : : * necessary SW fixup of the dirty and young bits in the PTE, while
1918 : : * handle_mm_fault() only guarantees to update these in the struct page.
1919 : : *
1920 : : * This is important for some architectures where those bits also gate the
1921 : : * access permission to the page because they are maintained in software. On
1922 : : * such architectures, gup() will not be enough to make a subsequent access
1923 : : * succeed.
1924 : : *
1925 : : * This should be called with the mm_sem held for read.
1926 : : */
1927 : 0 : int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
1928 : : unsigned long address, unsigned int fault_flags)
1929 : : {
1930 : : struct vm_area_struct *vma;
1931 : : int ret;
1932 : :
1933 : 0 : vma = find_extend_vma(mm, address);
1934 [ # # ][ # # ]: 0 : if (!vma || address < vma->vm_start)
1935 : : return -EFAULT;
1936 : :
1937 : 0 : ret = handle_mm_fault(mm, vma, address, fault_flags);
1938 [ # # ]: 0 : if (ret & VM_FAULT_ERROR) {
1939 [ # # ]: 0 : if (ret & VM_FAULT_OOM)
1940 : : return -ENOMEM;
1941 [ # # ]: 0 : if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
1942 : : return -EHWPOISON;
1943 [ # # ]: 0 : if (ret & VM_FAULT_SIGBUS)
1944 : : return -EFAULT;
1945 : 0 : BUG();
1946 : : }
1947 [ # # ]: 0 : if (tsk) {
1948 [ # # ]: 0 : if (ret & VM_FAULT_MAJOR)
1949 : 0 : tsk->maj_flt++;
1950 : : else
1951 : 0 : tsk->min_flt++;
1952 : : }
1953 : : return 0;
1954 : : }
1955 : :
1956 : : /*
1957 : : * get_user_pages() - pin user pages in memory
1958 : : * @tsk: the task_struct to use for page fault accounting, or
1959 : : * NULL if faults are not to be recorded.
1960 : : * @mm: mm_struct of target mm
1961 : : * @start: starting user address
1962 : : * @nr_pages: number of pages from start to pin
1963 : : * @write: whether pages will be written to by the caller
1964 : : * @force: whether to force write access even if user mapping is
1965 : : * readonly. This will result in the page being COWed even
1966 : : * in MAP_SHARED mappings. You do not want this.
1967 : : * @pages: array that receives pointers to the pages pinned.
1968 : : * Should be at least nr_pages long. Or NULL, if caller
1969 : : * only intends to ensure the pages are faulted in.
1970 : : * @vmas: array of pointers to vmas corresponding to each page.
1971 : : * Or NULL if the caller does not require them.
1972 : : *
1973 : : * Returns number of pages pinned. This may be fewer than the number
1974 : : * requested. If nr_pages is 0 or negative, returns 0. If no pages
1975 : : * were pinned, returns -errno. Each page returned must be released
1976 : : * with a put_page() call when it is finished with. vmas will only
1977 : : * remain valid while mmap_sem is held.
1978 : : *
1979 : : * Must be called with mmap_sem held for read or write.
1980 : : *
1981 : : * get_user_pages walks a process's page tables and takes a reference to
1982 : : * each struct page that each user address corresponds to at a given
1983 : : * instant. That is, it takes the page that would be accessed if a user
1984 : : * thread accesses the given user virtual address at that instant.
1985 : : *
1986 : : * This does not guarantee that the page exists in the user mappings when
1987 : : * get_user_pages returns, and there may even be a completely different
1988 : : * page there in some cases (eg. if mmapped pagecache has been invalidated
1989 : : * and subsequently re faulted). However it does guarantee that the page
1990 : : * won't be freed completely. And mostly callers simply care that the page
1991 : : * contains data that was valid *at some point in time*. Typically, an IO
1992 : : * or similar operation cannot guarantee anything stronger anyway because
1993 : : * locks can't be held over the syscall boundary.
1994 : : *
1995 : : * If write=0, the page must not be written to. If the page is written to,
1996 : : * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1997 : : * after the page is finished with, and before put_page is called.
1998 : : *
1999 : : * get_user_pages is typically used for fewer-copy IO operations, to get a
2000 : : * handle on the memory by some means other than accesses via the user virtual
2001 : : * addresses. The pages may be submitted for DMA to devices or accessed via
2002 : : * their kernel linear mapping (via the kmap APIs). Care should be taken to
2003 : : * use the correct cache flushing APIs.
2004 : : *
2005 : : * See also get_user_pages_fast, for performance critical applications.
2006 : : */
2007 : 0 : long get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
2008 : : unsigned long start, unsigned long nr_pages, int write,
2009 : : int force, struct page **pages, struct vm_area_struct **vmas)
2010 : : {
2011 : : int flags = FOLL_TOUCH;
2012 : :
2013 [ + - ]: 2464350 : if (pages)
2014 : : flags |= FOLL_GET;
2015 [ + + ]: 2464350 : if (write)
2016 : 2248446 : flags |= FOLL_WRITE;
2017 [ # # ]: 2464350 : if (force)
2018 : 2099148 : flags |= FOLL_FORCE;
2019 : :
2020 : 0 : return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas,
2021 : : NULL);
2022 : : }
2023 : : EXPORT_SYMBOL(get_user_pages);
2024 : :
2025 : : /**
2026 : : * get_dump_page() - pin user page in memory while writing it to core dump
2027 : : * @addr: user address
2028 : : *
2029 : : * Returns struct page pointer of user page pinned for dump,
2030 : : * to be freed afterwards by page_cache_release() or put_page().
2031 : : *
2032 : : * Returns NULL on any kind of failure - a hole must then be inserted into
2033 : : * the corefile, to preserve alignment with its headers; and also returns
2034 : : * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
2035 : : * allowing a hole to be left in the corefile to save diskspace.
2036 : : *
2037 : : * Called without mmap_sem, but after all other threads have been killed.
2038 : : */
2039 : : #ifdef CONFIG_ELF_CORE
2040 : 0 : struct page *get_dump_page(unsigned long addr)
2041 : : {
2042 : : struct vm_area_struct *vma;
2043 : : struct page *page;
2044 : :
2045 [ + + ]: 1538 : if (__get_user_pages(current, current->mm, addr, 1,
2046 : : FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma,
2047 : : NULL) < 1)
2048 : : return NULL;
2049 : 393 : flush_cache_page(vma, addr, page_to_pfn(page));
2050 : 393 : return page;
2051 : : }
2052 : : #endif /* CONFIG_ELF_CORE */
2053 : :
2054 : 0 : pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
2055 : : spinlock_t **ptl)
2056 : : {
2057 : 1119 : pgd_t * pgd = pgd_offset(mm, addr);
2058 : : pud_t * pud = pud_alloc(mm, pgd, addr);
2059 [ + - ]: 1119 : if (pud) {
2060 : 1119 : pmd_t * pmd = pmd_alloc(mm, pud, addr);
2061 [ + - ]: 1119 : if (pmd) {
2062 : : VM_BUG_ON(pmd_trans_huge(*pmd));
2063 [ + + ][ + - ]: 2238 : return pte_alloc_map_lock(mm, pmd, addr, ptl);
2064 : : }
2065 : : }
2066 : : return NULL;
2067 : : }
2068 : :
2069 : : /*
2070 : : * This is the old fallback for page remapping.
2071 : : *
2072 : : * For historical reasons, it only allows reserved pages. Only
2073 : : * old drivers should use this, and they needed to mark their
2074 : : * pages reserved for the old functions anyway.
2075 : : */
2076 : 0 : static int insert_page(struct vm_area_struct *vma, unsigned long addr,
2077 : 0 : struct page *page, pgprot_t prot)
2078 : : {
2079 : 0 : struct mm_struct *mm = vma->vm_mm;
2080 : : int retval;
2081 : : pte_t *pte;
2082 : : spinlock_t *ptl;
2083 : :
2084 : : retval = -EINVAL;
2085 [ # # ]: 0 : if (PageAnon(page))
2086 : : goto out;
2087 : : retval = -ENOMEM;
2088 : 0 : flush_dcache_page(page);
2089 : : pte = get_locked_pte(mm, addr, &ptl);
2090 [ # # ]: 0 : if (!pte)
2091 : : goto out;
2092 : : retval = -EBUSY;
2093 [ # # ]: 0 : if (!pte_none(*pte))
2094 : : goto out_unlock;
2095 : :
2096 : : /* Ok, finally just insert the thing.. */
2097 : : get_page(page);
2098 : 0 : inc_mm_counter_fast(mm, MM_FILEPAGES);
2099 : 0 : page_add_file_rmap(page);
2100 : 0 : set_pte_at(mm, addr, pte, mk_pte(page, prot));
2101 : :
2102 : : retval = 0;
2103 : 0 : pte_unmap_unlock(pte, ptl);
2104 : : return retval;
2105 : : out_unlock:
2106 : 0 : pte_unmap_unlock(pte, ptl);
2107 : : out:
2108 : : return retval;
2109 : : }
2110 : :
2111 : : /**
2112 : : * vm_insert_page - insert single page into user vma
2113 : : * @vma: user vma to map to
2114 : : * @addr: target user address of this page
2115 : : * @page: source kernel page
2116 : : *
2117 : : * This allows drivers to insert individual pages they've allocated
2118 : : * into a user vma.
2119 : : *
2120 : : * The page has to be a nice clean _individual_ kernel allocation.
2121 : : * If you allocate a compound page, you need to have marked it as
2122 : : * such (__GFP_COMP), or manually just split the page up yourself
2123 : : * (see split_page()).
2124 : : *
2125 : : * NOTE! Traditionally this was done with "remap_pfn_range()" which
2126 : : * took an arbitrary page protection parameter. This doesn't allow
2127 : : * that. Your vma protection will have to be set up correctly, which
2128 : : * means that if you want a shared writable mapping, you'd better
2129 : : * ask for a shared writable mapping!
2130 : : *
2131 : : * The page does not need to be reserved.
2132 : : *
2133 : : * Usually this function is called from f_op->mmap() handler
2134 : : * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
2135 : : * Caller must set VM_MIXEDMAP on vma if it wants to call this
2136 : : * function from other places, for example from page-fault handler.
2137 : : */
2138 : 0 : int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
2139 : : struct page *page)
2140 : : {
2141 [ # # ][ # # ]: 0 : if (addr < vma->vm_start || addr >= vma->vm_end)
2142 : : return -EFAULT;
2143 [ # # ]: 0 : if (!page_count(page))
2144 : : return -EINVAL;
2145 [ # # ]: 0 : if (!(vma->vm_flags & VM_MIXEDMAP)) {
2146 [ # # ]: 0 : BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem));
2147 [ # # ]: 0 : BUG_ON(vma->vm_flags & VM_PFNMAP);
2148 : 0 : vma->vm_flags |= VM_MIXEDMAP;
2149 : : }
2150 : 0 : return insert_page(vma, addr, page, vma->vm_page_prot);
2151 : : }
2152 : : EXPORT_SYMBOL(vm_insert_page);
2153 : :
2154 : 0 : static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2155 : : unsigned long pfn, pgprot_t prot)
2156 : : {
2157 : 0 : struct mm_struct *mm = vma->vm_mm;
2158 : : int retval;
2159 : : pte_t *pte, entry;
2160 : : spinlock_t *ptl;
2161 : :
2162 : : retval = -ENOMEM;
2163 : : pte = get_locked_pte(mm, addr, &ptl);
2164 [ # # ]: 0 : if (!pte)
2165 : : goto out;
2166 : : retval = -EBUSY;
2167 [ # # ]: 0 : if (!pte_none(*pte))
2168 : : goto out_unlock;
2169 : :
2170 : : /* Ok, finally just insert the thing.. */
2171 : 0 : entry = pte_mkspecial(pfn_pte(pfn, prot));
2172 : : set_pte_at(mm, addr, pte, entry);
2173 : : update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
2174 : :
2175 : : retval = 0;
2176 : : out_unlock:
2177 : 0 : pte_unmap_unlock(pte, ptl);
2178 : : out:
2179 : 0 : return retval;
2180 : : }
2181 : :
2182 : : /**
2183 : : * vm_insert_pfn - insert single pfn into user vma
2184 : : * @vma: user vma to map to
2185 : : * @addr: target user address of this page
2186 : : * @pfn: source kernel pfn
2187 : : *
2188 : : * Similar to vm_insert_page, this allows drivers to insert individual pages
2189 : : * they've allocated into a user vma. Same comments apply.
2190 : : *
2191 : : * This function should only be called from a vm_ops->fault handler, and
2192 : : * in that case the handler should return NULL.
2193 : : *
2194 : : * vma cannot be a COW mapping.
2195 : : *
2196 : : * As this is called only for pages that do not currently exist, we
2197 : : * do not need to flush old virtual caches or the TLB.
2198 : : */
2199 : 0 : int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
2200 : : unsigned long pfn)
2201 : : {
2202 : : int ret;
2203 : 0 : pgprot_t pgprot = vma->vm_page_prot;
2204 : : /*
2205 : : * Technically, architectures with pte_special can avoid all these
2206 : : * restrictions (same for remap_pfn_range). However we would like
2207 : : * consistency in testing and feature parity among all, so we should
2208 : : * try to keep these invariants in place for everybody.
2209 : : */
2210 [ # # ]: 0 : BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
2211 [ # # ]: 0 : BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
2212 : : (VM_PFNMAP|VM_MIXEDMAP));
2213 [ # # ][ # # ]: 0 : BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
2214 [ # # ][ # # ]: 0 : BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
2215 : :
2216 [ # # ][ # # ]: 0 : if (addr < vma->vm_start || addr >= vma->vm_end)
2217 : : return -EFAULT;
2218 : : if (track_pfn_insert(vma, &pgprot, pfn))
2219 : : return -EINVAL;
2220 : :
2221 : 0 : ret = insert_pfn(vma, addr, pfn, pgprot);
2222 : :
2223 : 0 : return ret;
2224 : : }
2225 : : EXPORT_SYMBOL(vm_insert_pfn);
2226 : :
2227 : 0 : int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
2228 : : unsigned long pfn)
2229 : : {
2230 [ # # ]: 0 : BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
2231 : :
2232 [ # # ][ # # ]: 0 : if (addr < vma->vm_start || addr >= vma->vm_end)
2233 : : return -EFAULT;
2234 : :
2235 : : /*
2236 : : * If we don't have pte special, then we have to use the pfn_valid()
2237 : : * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
2238 : : * refcount the page if pfn_valid is true (hence insert_page rather
2239 : : * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
2240 : : * without pte special, it would there be refcounted as a normal page.
2241 : : */
2242 [ # # ]: 0 : if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
2243 : : struct page *page;
2244 : :
2245 : 0 : page = pfn_to_page(pfn);
2246 : 0 : return insert_page(vma, addr, page, vma->vm_page_prot);
2247 : : }
2248 : 0 : return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
2249 : : }
2250 : : EXPORT_SYMBOL(vm_insert_mixed);
2251 : :
2252 : : /*
2253 : : * maps a range of physical memory into the requested pages. the old
2254 : : * mappings are removed. any references to nonexistent pages results
2255 : : * in null mappings (currently treated as "copy-on-access")
2256 : : */
2257 : 0 : static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
2258 : : unsigned long addr, unsigned long end,
2259 : : unsigned long pfn, pgprot_t prot)
2260 : : {
2261 : : pte_t *pte;
2262 : : spinlock_t *ptl;
2263 : :
2264 [ # # ][ # # ]: 0 : pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
2265 [ # # ]: 0 : if (!pte)
2266 : : return -ENOMEM;
2267 : : arch_enter_lazy_mmu_mode();
2268 : : do {
2269 [ # # ]: 0 : BUG_ON(!pte_none(*pte));
2270 : 0 : set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
2271 : 0 : pfn++;
2272 [ # # ]: 0 : } while (pte++, addr += PAGE_SIZE, addr != end);
2273 : : arch_leave_lazy_mmu_mode();
2274 : 0 : pte_unmap_unlock(pte - 1, ptl);
2275 : 0 : return 0;
2276 : : }
2277 : :
2278 : : static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
2279 : : unsigned long addr, unsigned long end,
2280 : : unsigned long pfn, pgprot_t prot)
2281 : : {
2282 : : pmd_t *pmd;
2283 : : unsigned long next;
2284 : :
2285 : : pfn -= addr >> PAGE_SHIFT;
2286 : : pmd = pmd_alloc(mm, pud, addr);
2287 [ # # ]: 0 : if (!pmd)
2288 : : return -ENOMEM;
2289 : : VM_BUG_ON(pmd_trans_huge(*pmd));
2290 : : do {
2291 : : next = pmd_addr_end(addr, end);
2292 [ # # ]: 0 : if (remap_pte_range(mm, pmd, addr, next,
2293 : : pfn + (addr >> PAGE_SHIFT), prot))
2294 : : return -ENOMEM;
2295 : : } while (pmd++, addr = next, addr != end);
2296 : : return 0;
2297 : : }
2298 : :
2299 : : static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
2300 : : unsigned long addr, unsigned long end,
2301 : : unsigned long pfn, pgprot_t prot)
2302 : : {
2303 : : pud_t *pud;
2304 : : unsigned long next;
2305 : :
2306 : 0 : pfn -= addr >> PAGE_SHIFT;
2307 : : pud = pud_alloc(mm, pgd, addr);
2308 [ # # ]: 0 : if (!pud)
2309 : : return -ENOMEM;
2310 : : do {
2311 : : next = pud_addr_end(addr, end);
2312 [ # # ]: 0 : if (remap_pmd_range(mm, pud, addr, next,
2313 : : pfn + (addr >> PAGE_SHIFT), prot))
2314 : : return -ENOMEM;
2315 : : } while (pud++, addr = next, addr != end);
2316 : : return 0;
2317 : : }
2318 : :
2319 : : /**
2320 : : * remap_pfn_range - remap kernel memory to userspace
2321 : : * @vma: user vma to map to
2322 : : * @addr: target user address to start at
2323 : : * @pfn: physical address of kernel memory
2324 : : * @size: size of map area
2325 : : * @prot: page protection flags for this mapping
2326 : : *
2327 : : * Note: this is only safe if the mm semaphore is held when called.
2328 : : */
2329 : 0 : int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
2330 : : unsigned long pfn, unsigned long size, pgprot_t prot)
2331 : : {
2332 : : pgd_t *pgd;
2333 : : unsigned long next;
2334 : 0 : unsigned long end = addr + PAGE_ALIGN(size);
2335 : 0 : struct mm_struct *mm = vma->vm_mm;
2336 : : int err;
2337 : :
2338 : : /*
2339 : : * Physically remapped pages are special. Tell the
2340 : : * rest of the world about it:
2341 : : * VM_IO tells people not to look at these pages
2342 : : * (accesses can have side effects).
2343 : : * VM_PFNMAP tells the core MM that the base pages are just
2344 : : * raw PFN mappings, and do not have a "struct page" associated
2345 : : * with them.
2346 : : * VM_DONTEXPAND
2347 : : * Disable vma merging and expanding with mremap().
2348 : : * VM_DONTDUMP
2349 : : * Omit vma from core dump, even when VM_IO turned off.
2350 : : *
2351 : : * There's a horrible special case to handle copy-on-write
2352 : : * behaviour that some programs depend on. We mark the "original"
2353 : : * un-COW'ed pages by matching them up with "vma->vm_pgoff".
2354 : : * See vm_normal_page() for details.
2355 : : */
2356 [ # # ]: 0 : if (is_cow_mapping(vma->vm_flags)) {
2357 [ # # ][ # # ]: 0 : if (addr != vma->vm_start || end != vma->vm_end)
2358 : : return -EINVAL;
2359 : 0 : vma->vm_pgoff = pfn;
2360 : : }
2361 : :
2362 : : err = track_pfn_remap(vma, &prot, pfn, addr, PAGE_ALIGN(size));
2363 : : if (err)
2364 : : return -EINVAL;
2365 : :
2366 : 0 : vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
2367 : :
2368 [ # # ]: 0 : BUG_ON(addr >= end);
2369 : 0 : pfn -= addr >> PAGE_SHIFT;
2370 : 0 : pgd = pgd_offset(mm, addr);
2371 : 0 : flush_cache_range(vma, addr, end);
2372 : : do {
2373 [ # # ]: 0 : next = pgd_addr_end(addr, end);
2374 : 0 : err = remap_pud_range(mm, pgd, addr, next,
2375 : 0 : pfn + (addr >> PAGE_SHIFT), prot);
2376 [ # # ]: 0 : if (err)
2377 : : break;
2378 [ # # ]: 0 : } while (pgd++, addr = next, addr != end);
2379 : :
2380 : : if (err)
2381 : : untrack_pfn(vma, pfn, PAGE_ALIGN(size));
2382 : :
2383 : : return err;
2384 : : }
2385 : : EXPORT_SYMBOL(remap_pfn_range);
2386 : :
2387 : : /**
2388 : : * vm_iomap_memory - remap memory to userspace
2389 : : * @vma: user vma to map to
2390 : : * @start: start of area
2391 : : * @len: size of area
2392 : : *
2393 : : * This is a simplified io_remap_pfn_range() for common driver use. The
2394 : : * driver just needs to give us the physical memory range to be mapped,
2395 : : * we'll figure out the rest from the vma information.
2396 : : *
2397 : : * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
2398 : : * whatever write-combining details or similar.
2399 : : */
2400 : 0 : int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
2401 : : {
2402 : : unsigned long vm_len, pfn, pages;
2403 : :
2404 : : /* Check that the physical memory area passed in looks valid */
2405 [ # # ]: 0 : if (start + len < start)
2406 : : return -EINVAL;
2407 : : /*
2408 : : * You *really* shouldn't map things that aren't page-aligned,
2409 : : * but we've historically allowed it because IO memory might
2410 : : * just have smaller alignment.
2411 : : */
2412 : 0 : len += start & ~PAGE_MASK;
2413 : 0 : pfn = start >> PAGE_SHIFT;
2414 : 0 : pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
2415 [ # # ]: 0 : if (pfn + pages < pfn)
2416 : : return -EINVAL;
2417 : :
2418 : : /* We start the mapping 'vm_pgoff' pages into the area */
2419 [ # # ]: 0 : if (vma->vm_pgoff > pages)
2420 : : return -EINVAL;
2421 : 0 : pfn += vma->vm_pgoff;
2422 : 0 : pages -= vma->vm_pgoff;
2423 : :
2424 : : /* Can we fit all of the mapping? */
2425 : 0 : vm_len = vma->vm_end - vma->vm_start;
2426 [ # # ]: 0 : if (vm_len >> PAGE_SHIFT > pages)
2427 : : return -EINVAL;
2428 : :
2429 : : /* Ok, let it rip */
2430 : 0 : return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
2431 : : }
2432 : : EXPORT_SYMBOL(vm_iomap_memory);
2433 : :
2434 : 0 : static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
2435 : : unsigned long addr, unsigned long end,
2436 : : pte_fn_t fn, void *data)
2437 : : {
2438 : : pte_t *pte;
2439 : : int err;
2440 : : pgtable_t token;
2441 : : spinlock_t *uninitialized_var(ptl);
2442 : :
2443 : : pte = (mm == &init_mm) ?
2444 [ # # ][ # # ]: 0 : pte_alloc_kernel(pmd, addr) :
[ # # ]
2445 [ # # ][ # # ]: 0 : pte_alloc_map_lock(mm, pmd, addr, &ptl);
2446 [ # # ]: 0 : if (!pte)
2447 : : return -ENOMEM;
2448 : :
2449 : : BUG_ON(pmd_huge(*pmd));
2450 : :
2451 : : arch_enter_lazy_mmu_mode();
2452 : :
2453 : 0 : token = pmd_pgtable(*pmd);
2454 : :
2455 : : do {
2456 : 0 : err = fn(pte++, token, addr, data);
2457 [ # # ]: 0 : if (err)
2458 : : break;
2459 [ # # ]: 0 : } while (addr += PAGE_SIZE, addr != end);
2460 : :
2461 : : arch_leave_lazy_mmu_mode();
2462 : :
2463 [ # # ]: 0 : if (mm != &init_mm)
2464 : 0 : pte_unmap_unlock(pte-1, ptl);
2465 : 0 : return err;
2466 : : }
2467 : :
2468 : : static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
2469 : : unsigned long addr, unsigned long end,
2470 : : pte_fn_t fn, void *data)
2471 : : {
2472 : : pmd_t *pmd;
2473 : : unsigned long next;
2474 : : int err;
2475 : :
2476 : : BUG_ON(pud_huge(*pud));
2477 : :
2478 : : pmd = pmd_alloc(mm, pud, addr);
2479 [ # # ]: 0 : if (!pmd)
2480 : : return -ENOMEM;
2481 : : do {
2482 : : next = pmd_addr_end(addr, end);
2483 : 0 : err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
2484 : : if (err)
2485 : : break;
2486 : : } while (pmd++, addr = next, addr != end);
2487 : : return err;
2488 : : }
2489 : :
2490 : : static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
2491 : : unsigned long addr, unsigned long end,
2492 : : pte_fn_t fn, void *data)
2493 : : {
2494 : : pud_t *pud;
2495 : : unsigned long next;
2496 : : int err;
2497 : :
2498 : : pud = pud_alloc(mm, pgd, addr);
2499 [ # # ]: 0 : if (!pud)
2500 : : return -ENOMEM;
2501 : : do {
2502 : : next = pud_addr_end(addr, end);
2503 : : err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
2504 : : if (err)
2505 : : break;
2506 : : } while (pud++, addr = next, addr != end);
2507 : : return err;
2508 : : }
2509 : :
2510 : : /*
2511 : : * Scan a region of virtual memory, filling in page tables as necessary
2512 : : * and calling a provided function on each leaf page table.
2513 : : */
2514 : 0 : int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2515 : : unsigned long size, pte_fn_t fn, void *data)
2516 : : {
2517 : : pgd_t *pgd;
2518 : : unsigned long next;
2519 : 0 : unsigned long end = addr + size;
2520 : : int err;
2521 : :
2522 [ # # ]: 0 : BUG_ON(addr >= end);
2523 : 0 : pgd = pgd_offset(mm, addr);
2524 : : do {
2525 [ # # ]: 0 : next = pgd_addr_end(addr, end);
2526 : : err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2527 [ # # ]: 0 : if (err)
2528 : : break;
2529 [ # # ]: 0 : } while (pgd++, addr = next, addr != end);
2530 : :
2531 : 0 : return err;
2532 : : }
2533 : : EXPORT_SYMBOL_GPL(apply_to_page_range);
2534 : :
2535 : : /*
2536 : : * handle_pte_fault chooses page fault handler according to an entry
2537 : : * which was read non-atomically. Before making any commitment, on
2538 : : * those architectures or configurations (e.g. i386 with PAE) which
2539 : : * might give a mix of unmatched parts, do_swap_page and do_nonlinear_fault
2540 : : * must check under lock before unmapping the pte and proceeding
2541 : : * (but do_wp_page is only called after already making such a check;
2542 : : * and do_anonymous_page can safely check later on).
2543 : : */
2544 : : static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2545 : : pte_t *page_table, pte_t orig_pte)
2546 : : {
2547 : : int same = 1;
2548 : : #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2549 : : if (sizeof(pte_t) > sizeof(unsigned long)) {
2550 : : spinlock_t *ptl = pte_lockptr(mm, pmd);
2551 : : spin_lock(ptl);
2552 : : same = pte_same(*page_table, orig_pte);
2553 : : spin_unlock(ptl);
2554 : : }
2555 : : #endif
2556 : 32 : pte_unmap(page_table);
2557 : : return same;
2558 : : }
2559 : :
2560 : : static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
2561 : : {
2562 : : /*
2563 : : * If the source page was a PFN mapping, we don't have
2564 : : * a "struct page" for it. We do a best-effort copy by
2565 : : * just copying from the original user address. If that
2566 : : * fails, we just zero-fill it. Live with it.
2567 : : */
2568 [ - + ]: 10375420 : if (unlikely(!src)) {
2569 : 0 : void *kaddr = kmap_atomic(dst);
2570 : 0 : void __user *uaddr = (void __user *)(va & PAGE_MASK);
2571 : :
2572 : : /*
2573 : : * This really shouldn't fail, because the page is there
2574 : : * in the page tables. But it might just be unreadable,
2575 : : * in which case we just give up and fill the result with
2576 : : * zeroes.
2577 : : */
2578 [ # # ]: 0 : if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
2579 : 0 : clear_page(kaddr);
2580 : 0 : kunmap_atomic(kaddr);
2581 : 0 : flush_dcache_page(dst);
2582 : : } else
2583 : 10375420 : copy_user_highpage(dst, src, va, vma);
2584 : : }
2585 : :
2586 : : /*
2587 : : * This routine handles present pages, when users try to write
2588 : : * to a shared page. It is done by copying the page to a new address
2589 : : * and decrementing the shared-page counter for the old page.
2590 : : *
2591 : : * Note that this routine assumes that the protection checks have been
2592 : : * done by the caller (the low-level page fault routine in most cases).
2593 : : * Thus we can safely just mark it writable once we've done any necessary
2594 : : * COW.
2595 : : *
2596 : : * We also mark the page dirty at this point even though the page will
2597 : : * change only once the write actually happens. This avoids a few races,
2598 : : * and potentially makes it more efficient.
2599 : : *
2600 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
2601 : : * but allow concurrent faults), with pte both mapped and locked.
2602 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
2603 : : */
2604 : 0 : static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2605 : 10742059 : unsigned long address, pte_t *page_table, pmd_t *pmd,
2606 : : spinlock_t *ptl, pte_t orig_pte)
2607 : : __releases(ptl)
2608 : : {
2609 : 28533882 : struct page *old_page, *new_page = NULL;
2610 : : pte_t entry;
2611 : : int ret = 0;
2612 : : int page_mkwrite = 0;
2613 : : struct page *dirty_page = NULL;
2614 : : unsigned long mmun_start = 0; /* For mmu_notifiers */
2615 : : unsigned long mmun_end = 0; /* For mmu_notifiers */
2616 : :
2617 : 18424475 : old_page = vm_normal_page(vma, address, orig_pte);
2618 [ + + ]: 18411587 : if (!old_page) {
2619 : : /*
2620 : : * VM_MIXEDMAP !pfn_valid() case
2621 : : *
2622 : : * We should not cow pages in a shared writeable mapping.
2623 : : * Just mark the pages writable as we can't do any dirty
2624 : : * accounting on raw pfn maps.
2625 : : */
2626 [ - + ]: 253179 : if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2627 : : (VM_WRITE|VM_SHARED))
2628 : : goto reuse;
2629 : : goto gotten;
2630 : : }
2631 : :
2632 : : /*
2633 : : * Take out anonymous pages first, anonymous shared vmas are
2634 : : * not dirty accountable.
2635 : : */
2636 [ + + ]: 18158408 : if (PageAnon(old_page) && !PageKsm(old_page)) {
2637 [ + + ]: 17552782 : if (!trylock_page(old_page)) {
2638 : : page_cache_get(old_page);
2639 : 68 : pte_unmap_unlock(page_table, ptl);
2640 : : lock_page(old_page);
2641 : 68 : page_table = pte_offset_map_lock(mm, pmd, address,
2642 : : &ptl);
2643 [ - + ]: 68 : if (!pte_same(*page_table, orig_pte)) {
2644 : 0 : unlock_page(old_page);
2645 : 0 : goto unlock;
2646 : : }
2647 : 68 : page_cache_release(old_page);
2648 : : }
2649 [ + + ]: 17552782 : if (reuse_swap_page(old_page)) {
2650 : : /*
2651 : : * The page is all ours. Move it to our anon_vma so
2652 : : * the rmap code will not search our parent or siblings.
2653 : : * Protected against the rmap code by the page lock.
2654 : : */
2655 : 7687624 : page_move_anon_rmap(old_page, vma, address);
2656 : 7687622 : unlock_page(old_page);
2657 : 7687607 : goto reuse;
2658 : : }
2659 : 9883255 : unlock_page(old_page);
2660 [ + + ]: 605817 : } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2661 : : (VM_WRITE|VM_SHARED))) {
2662 : : /*
2663 : : * Only catch write-faults on shared writable pages,
2664 : : * read-only shared pages can get COWed by
2665 : : * get_user_pages(.write=1, .force=1).
2666 : : */
2667 [ + - ][ + - ]: 113610 : if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2668 : : struct vm_fault vmf;
2669 : : int tmp;
2670 : :
2671 : 113610 : vmf.virtual_address = (void __user *)(address &
2672 : : PAGE_MASK);
2673 : 113610 : vmf.pgoff = old_page->index;
2674 : 113610 : vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2675 : 113610 : vmf.page = old_page;
2676 : :
2677 : : /*
2678 : : * Notify the address space that the page is about to
2679 : : * become writable so that it can prohibit this or wait
2680 : : * for the page to get into an appropriate state.
2681 : : *
2682 : : * We do this without the lock held, so that it can
2683 : : * sleep if it needs to.
2684 : : */
2685 : : page_cache_get(old_page);
2686 : 113610 : pte_unmap_unlock(page_table, ptl);
2687 : :
2688 : 113610 : tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2689 [ + - ]: 113610 : if (unlikely(tmp &
2690 : : (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2691 : : ret = tmp;
2692 : 0 : goto unwritable_page;
2693 : : }
2694 [ - + ]: 113610 : if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2695 : : lock_page(old_page);
2696 [ # # ]: 0 : if (!old_page->mapping) {
2697 : : ret = 0; /* retry the fault */
2698 : 0 : unlock_page(old_page);
2699 : 0 : goto unwritable_page;
2700 : : }
2701 : : } else
2702 : : VM_BUG_ON(!PageLocked(old_page));
2703 : :
2704 : : /*
2705 : : * Since we dropped the lock we need to revalidate
2706 : : * the PTE as someone else may have changed it. If
2707 : : * they did, we just return, as we can count on the
2708 : : * MMU to tell us if they didn't also make it writable.
2709 : : */
2710 : 113610 : page_table = pte_offset_map_lock(mm, pmd, address,
2711 : : &ptl);
2712 [ - + ]: 113610 : if (!pte_same(*page_table, orig_pte)) {
2713 : 0 : unlock_page(old_page);
2714 : 113610 : goto unlock;
2715 : : }
2716 : :
2717 : : page_mkwrite = 1;
2718 : : }
2719 : : dirty_page = old_page;
2720 : : get_page(dirty_page);
2721 : :
2722 : : reuse:
2723 : : /*
2724 : : * Clear the pages cpupid information as the existing
2725 : : * information potentially belongs to a now completely
2726 : : * unrelated process.
2727 : : */
2728 : : if (old_page)
2729 : : page_cpupid_xchg_last(old_page, (1 << LAST_CPUPID_SHIFT) - 1);
2730 : :
2731 : 7801217 : flush_cache_page(vma, address, pte_pfn(orig_pte));
2732 : : entry = pte_mkyoung(orig_pte);
2733 : : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2734 : 7801206 : if (ptep_set_access_flags(vma, address, page_table, entry,1))
2735 : : update_mmu_cache(vma, address, page_table);
2736 : 7801222 : pte_unmap_unlock(page_table, ptl);
2737 : : ret |= VM_FAULT_WRITE;
2738 : :
2739 [ + + ]: 7801233 : if (!dirty_page)
2740 : : return ret;
2741 : :
2742 : : /*
2743 : : * Yes, Virginia, this is actually required to prevent a race
2744 : : * with clear_page_dirty_for_io() from clearing the page dirty
2745 : : * bit after it clear all dirty ptes, but before a racing
2746 : : * do_wp_page installs a dirty pte.
2747 : : *
2748 : : * __do_fault is protected similarly.
2749 : : */
2750 [ - + ]: 113610 : if (!page_mkwrite) {
2751 : : wait_on_page_locked(dirty_page);
2752 : 0 : set_page_dirty_balance(dirty_page, page_mkwrite);
2753 : : /* file_update_time outside page_lock */
2754 [ # # ]: 0 : if (vma->vm_file)
2755 : 0 : file_update_time(vma->vm_file);
2756 : : }
2757 : 113610 : put_page(dirty_page);
2758 [ + - ]: 113610 : if (page_mkwrite) {
2759 : 113610 : struct address_space *mapping = dirty_page->mapping;
2760 : :
2761 : 113610 : set_page_dirty(dirty_page);
2762 : 113610 : unlock_page(dirty_page);
2763 : 113610 : page_cache_release(dirty_page);
2764 [ + - ]: 113610 : if (mapping) {
2765 : : /*
2766 : : * Some device drivers do not set page.mapping
2767 : : * but still dirty their pages
2768 : : */
2769 : 113610 : balance_dirty_pages_ratelimited(mapping);
2770 : : }
2771 : : }
2772 : :
2773 : : return ret;
2774 : : }
2775 : :
2776 : : /*
2777 : : * Ok, we need to copy. Oh, well..
2778 : : */
2779 : : page_cache_get(old_page);
2780 : : gotten:
2781 : 10628572 : pte_unmap_unlock(page_table, ptl);
2782 : :
2783 [ + + ]: 10628662 : if (unlikely(anon_vma_prepare(vma)))
2784 : : goto oom;
2785 : :
2786 [ + + ]: 10628658 : if (is_zero_pfn(pte_pfn(orig_pte))) {
2787 : : new_page = alloc_zeroed_user_highpage_movable(vma, address);
2788 [ + - ]: 253178 : if (!new_page)
2789 : : goto oom;
2790 : : } else {
2791 : : new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2792 [ + ]: 10375410 : if (!new_page)
2793 : : goto oom;
2794 : : cow_user_page(new_page, old_page, address, vma);
2795 : : }
2796 : : __SetPageUptodate(new_page);
2797 : :
2798 : : if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
2799 : : goto oom_free_new;
2800 : :
2801 : : mmun_start = address & PAGE_MASK;
2802 : : mmun_end = mmun_start + PAGE_SIZE;
2803 : : mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
2804 : :
2805 : : /*
2806 : : * Re-check the pte - we dropped the lock
2807 : : */
2808 : 10628381 : page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2809 [ + + ]: 10628665 : if (likely(pte_same(*page_table, orig_pte))) {
2810 [ + + ]: 10628654 : if (old_page) {
2811 [ + + ]: 10375474 : if (!PageAnon(old_page)) {
2812 : 492216 : dec_mm_counter_fast(mm, MM_FILEPAGES);
2813 : 492214 : inc_mm_counter_fast(mm, MM_ANONPAGES);
2814 : : }
2815 : : } else
2816 : 253180 : inc_mm_counter_fast(mm, MM_ANONPAGES);
2817 : 10628653 : flush_cache_page(vma, address, pte_pfn(orig_pte));
2818 : 10628623 : entry = mk_pte(new_page, vma->vm_page_prot);
2819 : : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2820 : : /*
2821 : : * Clear the pte entry and flush it first, before updating the
2822 : : * pte with the new entry. This will avoid a race condition
2823 : : * seen in the presence of one thread doing SMC and another
2824 : : * thread doing COW.
2825 : : */
2826 : 10628623 : ptep_clear_flush(vma, address, page_table);
2827 : 10628590 : page_add_new_anon_rmap(new_page, vma, address);
2828 : : /*
2829 : : * We call the notify macro here because, when using secondary
2830 : : * mmu page tables (such as kvm shadow page tables), we want the
2831 : : * new page to be mapped directly into the secondary page table.
2832 : : */
2833 : : set_pte_at_notify(mm, address, page_table, entry);
2834 : : update_mmu_cache(vma, address, page_table);
2835 [ + + ]: 10628267 : if (old_page) {
2836 : : /*
2837 : : * Only after switching the pte to the new page may
2838 : : * we remove the mapcount here. Otherwise another
2839 : : * process may come and find the rmap count decremented
2840 : : * before the pte is switched to the new page, and
2841 : : * "reuse" the old page writing into it while our pte
2842 : : * here still points into it and can be read by other
2843 : : * threads.
2844 : : *
2845 : : * The critical issue is to order this
2846 : : * page_remove_rmap with the ptp_clear_flush above.
2847 : : * Those stores are ordered by (if nothing else,)
2848 : : * the barrier present in the atomic_add_negative
2849 : : * in page_remove_rmap.
2850 : : *
2851 : : * Then the TLB flush in ptep_clear_flush ensures that
2852 : : * no process can access the old page before the
2853 : : * decremented mapcount is visible. And the old page
2854 : : * cannot be reused until after the decremented
2855 : : * mapcount is visible. So transitively, TLBs to
2856 : : * old page will be flushed before it can be reused.
2857 : : */
2858 : 10628267 : page_remove_rmap(old_page);
2859 : : }
2860 : :
2861 : : /* Free the old page.. */
2862 : : new_page = old_page;
2863 : : ret |= VM_FAULT_WRITE;
2864 : : } else
2865 : : mem_cgroup_uncharge_page(new_page);
2866 : :
2867 [ + + ]: 10628644 : if (new_page)
2868 : 10375503 : page_cache_release(new_page);
2869 : : unlock:
2870 : 10628657 : pte_unmap_unlock(page_table, ptl);
2871 : : if (mmun_end > mmun_start)
2872 : : mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
2873 [ + + ]: 10628681 : if (old_page) {
2874 : : /*
2875 : : * Don't let another task, with possibly unlocked vma,
2876 : : * keep the mlocked page.
2877 : : */
2878 [ + ][ + + ]: 10375503 : if ((ret & VM_FAULT_WRITE) && (vma->vm_flags & VM_LOCKED)) {
2879 : : lock_page(old_page); /* LRU manipulation */
2880 : 13 : munlock_vma_page(old_page);
2881 : 13 : unlock_page(old_page);
2882 : : }
2883 : 10375503 : page_cache_release(old_page);
2884 : : }
2885 : 10628595 : return ret;
2886 : : oom_free_new:
2887 : : page_cache_release(new_page);
2888 : : oom:
2889 [ # # ]: 0 : if (old_page)
2890 : 0 : page_cache_release(old_page);
2891 : : return VM_FAULT_OOM;
2892 : :
2893 : : unwritable_page:
2894 : 0 : page_cache_release(old_page);
2895 : 0 : return ret;
2896 : : }
2897 : :
2898 : 0 : static void unmap_mapping_range_vma(struct vm_area_struct *vma,
2899 : : unsigned long start_addr, unsigned long end_addr,
2900 : : struct zap_details *details)
2901 : : {
2902 : 5 : zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
2903 : 5 : }
2904 : :
2905 : : static inline void unmap_mapping_range_tree(struct rb_root *root,
2906 : : struct zap_details *details)
2907 : : {
2908 : 5 : struct vm_area_struct *vma;
2909 : : pgoff_t vba, vea, zba, zea;
2910 : :
2911 [ + + ]: 12 : vma_interval_tree_foreach(vma, root,
2912 : : details->first_index, details->last_index) {
2913 : :
2914 : 5 : vba = vma->vm_pgoff;
2915 : 5 : vea = vba + vma_pages(vma) - 1;
2916 : : /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2917 : 5 : zba = details->first_index;
2918 [ - + ]: 5 : if (zba < vba)
2919 : : zba = vba;
2920 : 5 : zea = details->last_index;
2921 [ + + ]: 5 : if (zea > vea)
2922 : : zea = vea;
2923 : :
2924 : 5 : unmap_mapping_range_vma(vma,
2925 : 5 : ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2926 : 5 : ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2927 : : details);
2928 : : }
2929 : : }
2930 : :
2931 : : static inline void unmap_mapping_range_list(struct list_head *head,
2932 : : struct zap_details *details)
2933 : : {
2934 : : struct vm_area_struct *vma;
2935 : :
2936 : : /*
2937 : : * In nonlinear VMAs there is no correspondence between virtual address
2938 : : * offset and file offset. So we must perform an exhaustive search
2939 : : * across *all* the pages in each nonlinear VMA, not just the pages
2940 : : * whose virtual address lies outside the file truncation point.
2941 : : */
2942 [ # # ]: 0 : list_for_each_entry(vma, head, shared.nonlinear) {
2943 : 0 : details->nonlinear_vma = vma;
2944 : 0 : unmap_mapping_range_vma(vma, vma->vm_start, vma->vm_end, details);
2945 : : }
2946 : : }
2947 : :
2948 : : /**
2949 : : * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
2950 : : * @mapping: the address space containing mmaps to be unmapped.
2951 : : * @holebegin: byte in first page to unmap, relative to the start of
2952 : : * the underlying file. This will be rounded down to a PAGE_SIZE
2953 : : * boundary. Note that this is different from truncate_pagecache(), which
2954 : : * must keep the partial page. In contrast, we must get rid of
2955 : : * partial pages.
2956 : : * @holelen: size of prospective hole in bytes. This will be rounded
2957 : : * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2958 : : * end of the file.
2959 : : * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2960 : : * but 0 when invalidating pagecache, don't throw away private data.
2961 : : */
2962 : 0 : void unmap_mapping_range(struct address_space *mapping,
2963 : : loff_t const holebegin, loff_t const holelen, int even_cows)
2964 : : {
2965 : : struct zap_details details;
2966 : 68660 : pgoff_t hba = holebegin >> PAGE_SHIFT;
2967 : 68660 : pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2968 : :
2969 : : /* Check for overflow. */
2970 : : if (sizeof(holelen) > sizeof(hlen)) {
2971 : 68660 : long long holeend =
2972 : 68660 : (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2973 [ - + ]: 68660 : if (holeend & ~(long long)ULONG_MAX)
2974 : 0 : hlen = ULONG_MAX - hba + 1;
2975 : : }
2976 : :
2977 [ + + ]: 68660 : details.check_mapping = even_cows? NULL: mapping;
2978 : 68660 : details.nonlinear_vma = NULL;
2979 : 68660 : details.first_index = hba;
2980 : 68660 : details.last_index = hba + hlen - 1;
2981 [ + + ]: 68660 : if (details.last_index < details.first_index)
2982 : 63903 : details.last_index = ULONG_MAX;
2983 : :
2984 : :
2985 : 68660 : mutex_lock(&mapping->i_mmap_mutex);
2986 [ + + ]: 68661 : if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
2987 : 7 : unmap_mapping_range_tree(&mapping->i_mmap, &details);
2988 [ - + ]: 68661 : if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2989 : : unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2990 : 68661 : mutex_unlock(&mapping->i_mmap_mutex);
2991 : 68661 : }
2992 : : EXPORT_SYMBOL(unmap_mapping_range);
2993 : :
2994 : : /*
2995 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
2996 : : * but allow concurrent faults), and pte mapped but not yet locked.
2997 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
2998 : : */
2999 : 0 : static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
3000 : 0 : unsigned long address, pte_t *page_table, pmd_t *pmd,
3001 : : unsigned int flags, pte_t orig_pte)
3002 : : {
3003 : : spinlock_t *ptl;
3004 : : struct page *page, *swapcache;
3005 : : swp_entry_t entry;
3006 : : pte_t pte;
3007 : : int locked;
3008 : : struct mem_cgroup *ptr;
3009 : : int exclusive = 0;
3010 : : int ret = 0;
3011 : :
3012 : : if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3013 : : goto out;
3014 : :
3015 : : entry = pte_to_swp_entry(orig_pte);
3016 [ # # ]: 0 : if (unlikely(non_swap_entry(entry))) {
3017 [ # # ]: 0 : if (is_migration_entry(entry)) {
3018 : 0 : migration_entry_wait(mm, pmd, address);
3019 : : } else if (is_hwpoison_entry(entry)) {
3020 : : ret = VM_FAULT_HWPOISON;
3021 : : } else {
3022 : 0 : print_bad_pte(vma, address, orig_pte, NULL);
3023 : : ret = VM_FAULT_SIGBUS;
3024 : : }
3025 : : goto out;
3026 : : }
3027 : : delayacct_set_flag(DELAYACCT_PF_SWAPIN);
3028 : 0 : page = lookup_swap_cache(entry);
3029 [ # # ]: 0 : if (!page) {
3030 : 0 : page = swapin_readahead(entry,
3031 : : GFP_HIGHUSER_MOVABLE, vma, address);
3032 [ # # ]: 0 : if (!page) {
3033 : : /*
3034 : : * Back out if somebody else faulted in this pte
3035 : : * while we released the pte lock.
3036 : : */
3037 : 0 : page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3038 [ # # ]: 0 : if (likely(pte_same(*page_table, orig_pte)))
3039 : : ret = VM_FAULT_OOM;
3040 : : delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3041 : : goto unlock;
3042 : : }
3043 : :
3044 : : /* Had to read the page from swap area: Major fault */
3045 : : ret = VM_FAULT_MAJOR;
3046 : : count_vm_event(PGMAJFAULT);
3047 : : mem_cgroup_count_vm_event(mm, PGMAJFAULT);
3048 : : } else if (PageHWPoison(page)) {
3049 : : /*
3050 : : * hwpoisoned dirty swapcache pages are kept for killing
3051 : : * owner processes (which may be unknown at hwpoison time)
3052 : : */
3053 : : ret = VM_FAULT_HWPOISON;
3054 : : delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3055 : : swapcache = page;
3056 : : goto out_release;
3057 : : }
3058 : :
3059 : : swapcache = page;
3060 : : locked = lock_page_or_retry(page, mm, flags);
3061 : :
3062 : : delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3063 [ # # ]: 0 : if (!locked) {
3064 : 0 : ret |= VM_FAULT_RETRY;
3065 : 0 : goto out_release;
3066 : : }
3067 : :
3068 : : /*
3069 : : * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
3070 : : * release the swapcache from under us. The page pin, and pte_same
3071 : : * test below, are not enough to exclude that. Even if it is still
3072 : : * swapcache, we need to check that the page's swap has not changed.
3073 : : */
3074 [ # # ][ # # ]: 0 : if (unlikely(!PageSwapCache(page) || page_private(page) != entry.val))
3075 : : goto out_page;
3076 : :
3077 : : page = ksm_might_need_to_copy(page, vma, address);
3078 [ # # ]: 0 : if (unlikely(!page)) {
3079 : : ret = VM_FAULT_OOM;
3080 : : page = swapcache;
3081 : : goto out_page;
3082 : : }
3083 : :
3084 : : if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
3085 : : ret = VM_FAULT_OOM;
3086 : : goto out_page;
3087 : : }
3088 : :
3089 : : /*
3090 : : * Back out if somebody else already faulted in this pte.
3091 : : */
3092 : 0 : page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3093 [ # # ]: 0 : if (unlikely(!pte_same(*page_table, orig_pte)))
3094 : : goto out_nomap;
3095 : :
3096 [ # # ]: 0 : if (unlikely(!PageUptodate(page))) {
3097 : : ret = VM_FAULT_SIGBUS;
3098 : : goto out_nomap;
3099 : : }
3100 : :
3101 : : /*
3102 : : * The page isn't present yet, go ahead with the fault.
3103 : : *
3104 : : * Be careful about the sequence of operations here.
3105 : : * To get its accounting right, reuse_swap_page() must be called
3106 : : * while the page is counted on swap but not yet in mapcount i.e.
3107 : : * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
3108 : : * must be called after the swap_free(), or it will never succeed.
3109 : : * Because delete_from_swap_page() may be called by reuse_swap_page(),
3110 : : * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
3111 : : * in page->private. In this case, a record in swap_cgroup is silently
3112 : : * discarded at swap_free().
3113 : : */
3114 : :
3115 : 0 : inc_mm_counter_fast(mm, MM_ANONPAGES);
3116 : 0 : dec_mm_counter_fast(mm, MM_SWAPENTS);
3117 : 0 : pte = mk_pte(page, vma->vm_page_prot);
3118 [ # # ][ # # ]: 0 : if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
3119 : : pte = maybe_mkwrite(pte_mkdirty(pte), vma);
3120 : 0 : flags &= ~FAULT_FLAG_WRITE;
3121 : 0 : ret |= VM_FAULT_WRITE;
3122 : : exclusive = 1;
3123 : : }
3124 : : flush_icache_page(vma, page);
3125 : : if (pte_swp_soft_dirty(orig_pte))
3126 : : pte = pte_mksoft_dirty(pte);
3127 : : set_pte_at(mm, address, page_table, pte);
3128 : : if (page == swapcache)
3129 : 0 : do_page_add_anon_rmap(page, vma, address, exclusive);
3130 : : else /* ksm created a completely new copy */
3131 : : page_add_new_anon_rmap(page, vma, address);
3132 : : /* It's better to call commit-charge after rmap is established */
3133 : : mem_cgroup_commit_charge_swapin(page, ptr);
3134 : :
3135 : 0 : swap_free(entry);
3136 [ # # ][ # # ]: 0 : if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
[ # # ]
3137 : 0 : try_to_free_swap(page);
3138 : 0 : unlock_page(page);
3139 : : if (page != swapcache) {
3140 : : /*
3141 : : * Hold the lock to avoid the swap entry to be reused
3142 : : * until we take the PT lock for the pte_same() check
3143 : : * (to avoid false positives from pte_same). For
3144 : : * further safety release the lock after the swap_free
3145 : : * so that the swap count won't change under a
3146 : : * parallel locked swapcache.
3147 : : */
3148 : : unlock_page(swapcache);
3149 : : page_cache_release(swapcache);
3150 : : }
3151 : :
3152 [ # # ]: 0 : if (flags & FAULT_FLAG_WRITE) {
3153 : 0 : ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
3154 [ # # ]: 0 : if (ret & VM_FAULT_ERROR)
3155 : : ret &= VM_FAULT_ERROR;
3156 : : goto out;
3157 : : }
3158 : :
3159 : : /* No need to invalidate - it was non-present before */
3160 : : update_mmu_cache(vma, address, page_table);
3161 : : unlock:
3162 : 0 : pte_unmap_unlock(page_table, ptl);
3163 : : out:
3164 : 0 : return ret;
3165 : : out_nomap:
3166 : : mem_cgroup_cancel_charge_swapin(ptr);
3167 : 0 : pte_unmap_unlock(page_table, ptl);
3168 : : out_page:
3169 : 0 : unlock_page(page);
3170 : : out_release:
3171 : 0 : page_cache_release(page);
3172 : : if (page != swapcache) {
3173 : : unlock_page(swapcache);
3174 : : page_cache_release(swapcache);
3175 : : }
3176 : 0 : return ret;
3177 : : }
3178 : :
3179 : : /*
3180 : : * This is like a special single-page "expand_{down|up}wards()",
3181 : : * except we must first make sure that 'address{-|+}PAGE_SIZE'
3182 : : * doesn't hit another vma.
3183 : : */
3184 : : static inline int check_stack_guard_page(struct vm_area_struct *vma, unsigned long address)
3185 : : {
3186 : 16103541 : address &= PAGE_MASK;
3187 [ + + ][ + + ]: 16103541 : if ((vma->vm_flags & VM_GROWSDOWN) && address == vma->vm_start) {
3188 : 1977800 : struct vm_area_struct *prev = vma->vm_prev;
3189 : :
3190 : : /*
3191 : : * Is there a mapping abutting this one below?
3192 : : *
3193 : : * That's only ok if it's the same stack mapping
3194 : : * that has gotten split..
3195 : : */
3196 [ + + ][ + + ]: 1977800 : if (prev && prev->vm_end == address)
3197 [ - + ]: 1 : return prev->vm_flags & VM_GROWSDOWN ? 0 : -ENOMEM;
3198 : :
3199 : 1977799 : expand_downwards(vma, address - PAGE_SIZE);
3200 : : }
3201 : : if ((vma->vm_flags & VM_GROWSUP) && address + PAGE_SIZE == vma->vm_end) {
3202 : : struct vm_area_struct *next = vma->vm_next;
3203 : :
3204 : : /* As VM_GROWSDOWN but s/below/above/ */
3205 : : if (next && next->vm_start == address + PAGE_SIZE)
3206 : : return next->vm_flags & VM_GROWSUP ? 0 : -ENOMEM;
3207 : :
3208 : : expand_upwards(vma, address + PAGE_SIZE);
3209 : : }
3210 : : return 0;
3211 : : }
3212 : :
3213 : : /*
3214 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
3215 : : * but allow concurrent faults), and pte mapped but not yet locked.
3216 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
3217 : : */
3218 : 0 : static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
3219 : 16100089 : unsigned long address, pte_t *page_table, pmd_t *pmd,
3220 : : unsigned int flags)
3221 : : {
3222 : : struct page *page;
3223 : : spinlock_t *ptl;
3224 : : pte_t entry;
3225 : :
3226 : 16103379 : pte_unmap(page_table);
3227 : :
3228 : : /* Check if we need to add a guard page to the stack */
3229 [ + - ]: 16103646 : if (check_stack_guard_page(vma, address) < 0)
3230 : : return VM_FAULT_SIGBUS;
3231 : :
3232 : : /* Use the zero-page for reads */
3233 [ + + ]: 16103646 : if (!(flags & FAULT_FLAG_WRITE)) {
3234 : 288451 : entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
3235 : : vma->vm_page_prot));
3236 : 288451 : page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3237 [ + ]: 288450 : if (!pte_none(*page_table))
3238 : : goto unlock;
3239 : : goto setpte;
3240 : : }
3241 : :
3242 : : /* Allocate our own private page. */
3243 [ + + ]: 15815195 : if (unlikely(anon_vma_prepare(vma)))
3244 : : goto oom;
3245 : : page = alloc_zeroed_user_highpage_movable(vma, address);
3246 [ + - ]: 15813878 : if (!page)
3247 : : goto oom;
3248 : : /*
3249 : : * The memory barrier inside __SetPageUptodate makes sure that
3250 : : * preceeding stores to the page contents become visible before
3251 : : * the set_pte_at() write.
3252 : : */
3253 : : __SetPageUptodate(page);
3254 : :
3255 : : if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
3256 : : goto oom_free_page;
3257 : :
3258 : 15811638 : entry = mk_pte(page, vma->vm_page_prot);
3259 [ + ]: 15811638 : if (vma->vm_flags & VM_WRITE)
3260 : : entry = pte_mkwrite(pte_mkdirty(entry));
3261 : :
3262 : 15811638 : page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3263 [ + - ]: 15814965 : if (!pte_none(*page_table))
3264 : : goto release;
3265 : :
3266 : 15814965 : inc_mm_counter_fast(mm, MM_ANONPAGES);
3267 : 15815131 : page_add_new_anon_rmap(page, vma, address);
3268 : : setpte:
3269 : : set_pte_at(mm, address, page_table, entry);
3270 : :
3271 : : /* No need to invalidate - it was non-present before */
3272 : : update_mmu_cache(vma, address, page_table);
3273 : : unlock:
3274 : 16103194 : pte_unmap_unlock(page_table, ptl);
3275 : 16103317 : return 0;
3276 : : release:
3277 : : mem_cgroup_uncharge_page(page);
3278 : 0 : page_cache_release(page);
3279 : 0 : goto unlock;
3280 : : oom_free_page:
3281 : : page_cache_release(page);
3282 : : oom:
3283 : : return VM_FAULT_OOM;
3284 : : }
3285 : :
3286 : : /*
3287 : : * __do_fault() tries to create a new page mapping. It aggressively
3288 : : * tries to share with existing pages, but makes a separate copy if
3289 : : * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
3290 : : * the next page fault.
3291 : : *
3292 : : * As this is called only for pages that do not currently exist, we
3293 : : * do not need to flush old virtual caches or the TLB.
3294 : : *
3295 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
3296 : : * but allow concurrent faults), and pte neither mapped nor locked.
3297 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
3298 : : */
3299 : 0 : static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3300 : 41160589 : unsigned long address, pmd_t *pmd,
3301 : : pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
3302 : : {
3303 : : pte_t *page_table;
3304 : : spinlock_t *ptl;
3305 : : struct page *page;
3306 : : struct page *cow_page;
3307 : : pte_t entry;
3308 : : int anon = 0;
3309 : : struct page *dirty_page = NULL;
3310 : : struct vm_fault vmf;
3311 : : int ret;
3312 : : int page_mkwrite = 0;
3313 : :
3314 : : /*
3315 : : * If we do COW later, allocate page befor taking lock_page()
3316 : : * on the file cache page. This will reduce lock holding time.
3317 : : */
3318 [ + + ][ + + ]: 41171577 : if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) {
3319 : :
3320 [ + - ]: 369922 : if (unlikely(anon_vma_prepare(vma)))
3321 : : return VM_FAULT_OOM;
3322 : :
3323 : : cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
3324 [ + + ]: 369921 : if (!cow_page)
3325 : : return VM_FAULT_OOM;
3326 : :
3327 : : if (mem_cgroup_newpage_charge(cow_page, mm, GFP_KERNEL)) {
3328 : : page_cache_release(cow_page);
3329 : : return VM_FAULT_OOM;
3330 : : }
3331 : : } else
3332 : : cow_page = NULL;
3333 : :
3334 : 41171575 : vmf.virtual_address = (void __user *)(address & PAGE_MASK);
3335 : 41171575 : vmf.pgoff = pgoff;
3336 : 41171575 : vmf.flags = flags;
3337 : 41171575 : vmf.page = NULL;
3338 : :
3339 : 41171575 : ret = vma->vm_ops->fault(vma, &vmf);
3340 [ + + ]: 41171504 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
3341 : : VM_FAULT_RETRY)))
3342 : : goto uncharge_out;
3343 : :
3344 : : if (unlikely(PageHWPoison(vmf.page))) {
3345 : : if (ret & VM_FAULT_LOCKED)
3346 : : unlock_page(vmf.page);
3347 : : ret = VM_FAULT_HWPOISON;
3348 : : goto uncharge_out;
3349 : : }
3350 : :
3351 : : /*
3352 : : * For consistency in subsequent calls, make the faulted page always
3353 : : * locked.
3354 : : */
3355 [ + + ]: 41160361 : if (unlikely(!(ret & VM_FAULT_LOCKED)))
3356 : 24 : lock_page(vmf.page);
3357 : : else
3358 : : VM_BUG_ON(!PageLocked(vmf.page));
3359 : :
3360 : : /*
3361 : : * Should we do an early C-O-W break?
3362 : : */
3363 : 41160629 : page = vmf.page;
3364 [ + + ]: 41160629 : if (flags & FAULT_FLAG_WRITE) {
3365 [ + + ]: 529434 : if (!(vma->vm_flags & VM_SHARED)) {
3366 : : page = cow_page;
3367 : : anon = 1;
3368 : 368496 : copy_user_highpage(page, vmf.page, address, vma);
3369 : : __SetPageUptodate(page);
3370 : : } else {
3371 : : /*
3372 : : * If the page will be shareable, see if the backing
3373 : : * address space wants to know that the page is about
3374 : : * to become writable
3375 : : */
3376 [ + + ]: 160938 : if (vma->vm_ops->page_mkwrite) {
3377 : : int tmp;
3378 : :
3379 : 150738 : unlock_page(page);
3380 : 150711 : vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
3381 : 150711 : tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
3382 [ + + ]: 150724 : if (unlikely(tmp &
3383 : : (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
3384 : : ret = tmp;
3385 : : goto unwritable_page;
3386 : : }
3387 [ - + ]: 150714 : if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
3388 : : lock_page(page);
3389 [ # # ]: 0 : if (!page->mapping) {
3390 : : ret = 0; /* retry the fault */
3391 : 0 : unlock_page(page);
3392 : 0 : goto unwritable_page;
3393 : : }
3394 : : } else
3395 : : VM_BUG_ON(!PageLocked(page));
3396 : : page_mkwrite = 1;
3397 : : }
3398 : : }
3399 : :
3400 : : }
3401 : :
3402 : 41160589 : page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
3403 : :
3404 : : /*
3405 : : * This silly early PAGE_DIRTY setting removes a race
3406 : : * due to the bad i386 page protection. But it's valid
3407 : : * for other architectures too.
3408 : : *
3409 : : * Note that if FAULT_FLAG_WRITE is set, we either now have
3410 : : * an exclusive copy of the page, or this is a shared mapping,
3411 : : * so we can make it writable and dirty to avoid having to
3412 : : * handle that later.
3413 : : */
3414 : : /* Only go through if we didn't race with anybody else... */
3415 [ + + ]: 82332886 : if (likely(pte_same(*page_table, orig_pte))) {
3416 : : flush_icache_page(vma, page);
3417 : 41161274 : entry = mk_pte(page, vma->vm_page_prot);
3418 [ + + ]: 41161274 : if (flags & FAULT_FLAG_WRITE)
3419 : : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
3420 : : else if (pte_file(orig_pte) && pte_file_soft_dirty(orig_pte))
3421 : : pte_mksoft_dirty(entry);
3422 [ + + ]: 41161274 : if (anon) {
3423 : 368490 : inc_mm_counter_fast(mm, MM_ANONPAGES);
3424 : 368495 : page_add_new_anon_rmap(page, vma, address);
3425 : : } else {
3426 : 40792784 : inc_mm_counter_fast(mm, MM_FILEPAGES);
3427 : 40793054 : page_add_file_rmap(page);
3428 [ + + ]: 40792827 : if (flags & FAULT_FLAG_WRITE) {
3429 : : dirty_page = page;
3430 : : get_page(dirty_page);
3431 : : }
3432 : : }
3433 : : set_pte_at(mm, address, page_table, entry);
3434 : :
3435 : : /* no need to invalidate: a not-present page won't be cached */
3436 : : update_mmu_cache(vma, address, page_table);
3437 : : } else {
3438 : : if (cow_page)
3439 : : mem_cgroup_uncharge_page(cow_page);
3440 [ - + ]: 35 : if (anon)
3441 : 0 : page_cache_release(page);
3442 : : else
3443 : : anon = 1; /* no anon but release faulted_page */
3444 : : }
3445 : :
3446 : 41160439 : pte_unmap_unlock(page_table, ptl);
3447 : :
3448 [ + + ]: 41161403 : if (dirty_page) {
3449 : 160915 : struct address_space *mapping = page->mapping;
3450 : : int dirtied = 0;
3451 : :
3452 [ + + ]: 160915 : if (set_page_dirty(dirty_page))
3453 : : dirtied = 1;
3454 : 160920 : unlock_page(dirty_page);
3455 : 160918 : put_page(dirty_page);
3456 [ + + ][ + + ]: 160913 : if ((dirtied || page_mkwrite) && mapping) {
3457 : : /*
3458 : : * Some device drivers do not set page.mapping but still
3459 : : * dirty their pages
3460 : : */
3461 : 160897 : balance_dirty_pages_ratelimited(mapping);
3462 : : }
3463 : :
3464 : : /* file_update_time outside page_lock */
3465 [ + + ][ + + ]: 161079 : if (vma->vm_file && !page_mkwrite)
3466 : 10181 : file_update_time(vma->vm_file);
3467 : : } else {
3468 : 41000488 : unlock_page(vmf.page);
3469 [ + + ]: 40998498 : if (anon)
3470 : 368516 : page_cache_release(vmf.page);
3471 : : }
3472 : :
3473 : 41159586 : return ret;
3474 : :
3475 : : unwritable_page:
3476 : 10 : page_cache_release(page);
3477 : 0 : return ret;
3478 : : uncharge_out:
3479 : : /* fs's fault handler get error */
3480 [ + + ]: 11143 : if (cow_page) {
3481 : : mem_cgroup_uncharge_page(cow_page);
3482 : 1429 : page_cache_release(cow_page);
3483 : : }
3484 : 11143 : return ret;
3485 : : }
3486 : :
3487 : 0 : static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3488 : : unsigned long address, pte_t *page_table, pmd_t *pmd,
3489 : : unsigned int flags, pte_t orig_pte)
3490 : : {
3491 : 82341162 : pgoff_t pgoff = (((address & PAGE_MASK)
3492 : 41170581 : - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
3493 : :
3494 : 41170581 : pte_unmap(page_table);
3495 : 41170973 : return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3496 : : }
3497 : :
3498 : : /*
3499 : : * Fault of a previously existing named mapping. Repopulate the pte
3500 : : * from the encoded file_pte if possible. This enables swappable
3501 : : * nonlinear vmas.
3502 : : *
3503 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
3504 : : * but allow concurrent faults), and pte mapped but not yet locked.
3505 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
3506 : : */
3507 : 0 : static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3508 : : unsigned long address, pte_t *page_table, pmd_t *pmd,
3509 : : unsigned int flags, pte_t orig_pte)
3510 : : {
3511 : : pgoff_t pgoff;
3512 : :
3513 : 32 : flags |= FAULT_FLAG_NONLINEAR;
3514 : :
3515 : : if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
3516 : : return 0;
3517 : :
3518 [ - + ]: 32 : if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
3519 : : /*
3520 : : * Page table corrupted: show pte and kill process.
3521 : : */
3522 : 0 : print_bad_pte(vma, address, orig_pte, NULL);
3523 : 0 : return VM_FAULT_SIGBUS;
3524 : : }
3525 : :
3526 : 32 : pgoff = pte_to_pgoff(orig_pte);
3527 : 32 : return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
3528 : : }
3529 : :
3530 : 0 : int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
3531 : : unsigned long addr, int page_nid,
3532 : : int *flags)
3533 : : {
3534 : : get_page(page);
3535 : :
3536 : : count_vm_numa_event(NUMA_HINT_FAULTS);
3537 [ # # ]: 0 : if (page_nid == numa_node_id()) {
3538 : : count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
3539 : 0 : *flags |= TNF_FAULT_LOCAL;
3540 : : }
3541 : :
3542 : 0 : return mpol_misplaced(page, vma, addr);
3543 : : }
3544 : :
3545 : 0 : int do_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
3546 : 0 : unsigned long addr, pte_t pte, pte_t *ptep, pmd_t *pmd)
3547 : : {
3548 : : struct page *page = NULL;
3549 : : spinlock_t *ptl;
3550 : : int page_nid = -1;
3551 : : int last_cpupid;
3552 : : int target_nid;
3553 : : bool migrated = false;
3554 : 0 : int flags = 0;
3555 : :
3556 : : /*
3557 : : * The "pte" at this point cannot be used safely without
3558 : : * validation through pte_unmap_same(). It's of NUMA type but
3559 : : * the pfn may be screwed if the read is non atomic.
3560 : : *
3561 : : * ptep_modify_prot_start is not called as this is clearing
3562 : : * the _PAGE_NUMA bit and it is not really expected that there
3563 : : * would be concurrent hardware modifications to the PTE.
3564 : : */
3565 : : ptl = pte_lockptr(mm, pmd);
3566 : : spin_lock(ptl);
3567 [ # # ]: 0 : if (unlikely(!pte_same(*ptep, pte))) {
3568 : 0 : pte_unmap_unlock(ptep, ptl);
3569 : 0 : goto out;
3570 : : }
3571 : :
3572 : : pte = pte_mknonnuma(pte);
3573 : : set_pte_at(mm, addr, ptep, pte);
3574 : : update_mmu_cache(vma, addr, ptep);
3575 : :
3576 : 0 : page = vm_normal_page(vma, addr, pte);
3577 [ # # ]: 0 : if (!page) {
3578 : 0 : pte_unmap_unlock(ptep, ptl);
3579 : 0 : return 0;
3580 : : }
3581 [ # # ]: 0 : BUG_ON(is_zero_pfn(page_to_pfn(page)));
3582 : :
3583 : : /*
3584 : : * Avoid grouping on DSO/COW pages in specific and RO pages
3585 : : * in general, RO pages shouldn't hurt as much anyway since
3586 : : * they can be in shared cache state.
3587 : : */
3588 [ # # ]: 0 : if (!pte_write(pte))
3589 : 0 : flags |= TNF_NO_GROUP;
3590 : :
3591 : : /*
3592 : : * Flag if the page is shared between multiple address spaces. This
3593 : : * is later used when determining whether to group tasks together
3594 : : */
3595 [ # # ][ # # ]: 0 : if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED))
3596 : 0 : flags |= TNF_SHARED;
3597 : :
3598 : : last_cpupid = page_cpupid_last(page);
3599 : : page_nid = page_to_nid(page);
3600 : 0 : target_nid = numa_migrate_prep(page, vma, addr, page_nid, &flags);
3601 : 0 : pte_unmap_unlock(ptep, ptl);
3602 [ # # ]: 0 : if (target_nid == -1) {
3603 : 0 : put_page(page);
3604 : 0 : goto out;
3605 : : }
3606 : :
3607 : : /* Migrate to the requested node */
3608 : : migrated = migrate_misplaced_page(page, vma, target_nid);
3609 : : if (migrated) {
3610 : : page_nid = target_nid;
3611 : : flags |= TNF_MIGRATED;
3612 : : }
3613 : :
3614 : : out:
3615 : : if (page_nid != -1)
3616 : : task_numa_fault(last_cpupid, page_nid, 1, flags);
3617 : : return 0;
3618 : : }
3619 : :
3620 : : /*
3621 : : * These routines also need to handle stuff like marking pages dirty
3622 : : * and/or accessed for architectures that don't do it in hardware (most
3623 : : * RISC architectures). The early dirtying is also good on the i386.
3624 : : *
3625 : : * There is also a hook called "update_mmu_cache()" that architectures
3626 : : * with external mmu caches can use to update those (ie the Sparc or
3627 : : * PowerPC hashed page tables that act as extended TLBs).
3628 : : *
3629 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
3630 : : * but allow concurrent faults), and pte mapped but not yet locked.
3631 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
3632 : : */
3633 : 0 : static int handle_pte_fault(struct mm_struct *mm,
3634 : : struct vm_area_struct *vma, unsigned long address,
3635 : 30739325 : pte_t *pte, pmd_t *pmd, unsigned int flags)
3636 : : {
3637 : : pte_t entry;
3638 : : spinlock_t *ptl;
3639 : :
3640 : 88011615 : entry = *pte;
3641 [ + + ]: 88011615 : if (!pte_present(entry)) {
3642 [ + + ]: 57272290 : if (pte_none(entry)) {
3643 [ + + ]: 57272258 : if (vma->vm_ops) {
3644 [ + + ]: 41170749 : if (likely(vma->vm_ops->fault))
3645 : 41170507 : return do_linear_fault(mm, vma, address,
3646 : : pte, pmd, flags, entry);
3647 : : }
3648 : 16101751 : return do_anonymous_page(mm, vma, address,
3649 : : pte, pmd, flags);
3650 : : }
3651 [ + - ]: 32 : if (pte_file(entry))
3652 : 32 : return do_nonlinear_fault(mm, vma, address,
3653 : : pte, pmd, flags, entry);
3654 : 0 : return do_swap_page(mm, vma, address,
3655 : : pte, pmd, flags, entry);
3656 : : }
3657 : :
3658 : : if (pte_numa(entry))
3659 : : return do_numa_page(mm, vma, address, entry, pte, pmd);
3660 : :
3661 : 30739325 : ptl = pte_lockptr(mm, pmd);
3662 : : spin_lock(ptl);
3663 [ + ]: 30772350 : if (unlikely(!pte_same(*pte, entry)))
3664 : : goto unlock;
3665 [ + + ]: 30772966 : if (flags & FAULT_FLAG_WRITE) {
3666 [ + + ]: 18649659 : if (!pte_write(entry))
3667 : 18421779 : return do_wp_page(mm, vma, address,
3668 : : pte, pmd, ptl, entry);
3669 : : entry = pte_mkdirty(entry);
3670 : : }
3671 : : entry = pte_mkyoung(entry);
3672 [ + + ]: 12351187 : if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
3673 : : update_mmu_cache(vma, address, pte);
3674 : : } else {
3675 : : /*
3676 : : * This is needed only for protection faults but the arch code
3677 : : * is not yet telling us if this is a protection fault or not.
3678 : : * This still avoids useless tlb flushes for .text page faults
3679 : : * with threads.
3680 : : */
3681 [ - + ]: 297 : if (flags & FAULT_FLAG_WRITE)
3682 : 0 : flush_tlb_fix_spurious_fault(vma, address);
3683 : : }
3684 : : unlock:
3685 : 12354575 : pte_unmap_unlock(pte, ptl);
3686 : 12354582 : return 0;
3687 : : }
3688 : :
3689 : : /*
3690 : : * By the time we get here, we already hold the mm semaphore
3691 : : */
3692 : 0 : static int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3693 : : unsigned long address, unsigned int flags)
3694 : : {
3695 : : pgd_t *pgd;
3696 : : pud_t *pud;
3697 : : pmd_t *pmd;
3698 : : pte_t *pte;
3699 : :
3700 : : if (unlikely(is_vm_hugetlb_page(vma)))
3701 : : return hugetlb_fault(mm, vma, address, flags);
3702 : :
3703 : : retry:
3704 : 88046991 : pgd = pgd_offset(mm, address);
3705 : : pud = pud_alloc(mm, pgd, address);
3706 [ + + ]: 88046991 : if (!pud)
3707 : : return VM_FAULT_OOM;
3708 : : pmd = pmd_alloc(mm, pud, address);
3709 [ + + ]: 88040640 : if (!pmd)
3710 : : return VM_FAULT_OOM;
3711 : : if (pmd_none(*pmd) && transparent_hugepage_enabled(vma)) {
3712 : : int ret = VM_FAULT_FALLBACK;
3713 : : if (!vma->vm_ops)
3714 : : ret = do_huge_pmd_anonymous_page(mm, vma, address,
3715 : : pmd, flags);
3716 : : if (!(ret & VM_FAULT_FALLBACK))
3717 : : return ret;
3718 : : } else {
3719 : : pmd_t orig_pmd = *pmd;
3720 : : int ret;
3721 : :
3722 : 88039631 : barrier();
3723 : : if (pmd_trans_huge(orig_pmd)) {
3724 : : unsigned int dirty = flags & FAULT_FLAG_WRITE;
3725 : :
3726 : : /*
3727 : : * If the pmd is splitting, return and retry the
3728 : : * the fault. Alternative: wait until the split
3729 : : * is done, and goto retry.
3730 : : */
3731 : : if (pmd_trans_splitting(orig_pmd))
3732 : : return 0;
3733 : :
3734 : : if (pmd_numa(orig_pmd))
3735 : : return do_huge_pmd_numa_page(mm, vma, address,
3736 : : orig_pmd, pmd);
3737 : :
3738 : : if (dirty && !pmd_write(orig_pmd)) {
3739 : : ret = do_huge_pmd_wp_page(mm, vma, address, pmd,
3740 : : orig_pmd);
3741 : : /*
3742 : : * If COW results in an oom, the huge pmd will
3743 : : * have been split, so retry the fault on the
3744 : : * pte for a smaller charge.
3745 : : */
3746 : : if (unlikely(ret & VM_FAULT_OOM))
3747 : : goto retry;
3748 : : return ret;
3749 : : } else {
3750 : : huge_pmd_set_accessed(mm, vma, address, pmd,
3751 : : orig_pmd, dirty);
3752 : : }
3753 : :
3754 : : return 0;
3755 : : }
3756 : : }
3757 : :
3758 : : /* THP should already have been handled */
3759 : : BUG_ON(pmd_numa(*pmd));
3760 : :
3761 : : /*
3762 : : * Use __pte_alloc instead of pte_alloc_map, because we can't
3763 : : * run pte_offset_map on the pmd, if an huge pmd could
3764 : : * materialize from under us from a different thread.
3765 : : */
3766 [ + + + + ]: 88403415 : if (unlikely(pmd_none(*pmd)) &&
3767 : 362451 : unlikely(__pte_alloc(mm, vma, pmd, address)))
3768 : : return VM_FAULT_OOM;
3769 : : /* if an huge pmd materialized from under us just retry later */
3770 : : if (unlikely(pmd_trans_huge(*pmd)))
3771 : : return 0;
3772 : : /*
3773 : : * A regular pmd is established and it can't morph into a huge pmd
3774 : : * from under us anymore at this point because we hold the mmap_sem
3775 : : * read mode and khugepaged takes it in write mode. So now it's
3776 : : * safe to run pte_offset_map().
3777 : : */
3778 : 88040950 : pte = pte_offset_map(pmd, address);
3779 : :
3780 : 88011725 : return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3781 : : }
3782 : :
3783 : 0 : int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3784 : : unsigned long address, unsigned int flags)
3785 : : {
3786 : : int ret;
3787 : :
3788 : 88048785 : __set_current_state(TASK_RUNNING);
3789 : :
3790 : : count_vm_event(PGFAULT);
3791 : : mem_cgroup_count_vm_event(mm, PGFAULT);
3792 : :
3793 : : /* do counter updates before entering really critical section. */
3794 : 88055416 : check_sync_rss_stat(current);
3795 : :
3796 : : /*
3797 : : * Enable the memcg OOM handling for faults triggered in user
3798 : : * space. Kernel faults are handled more gracefully.
3799 : : */
3800 : : if (flags & FAULT_FLAG_USER)
3801 : : mem_cgroup_oom_enable();
3802 : :
3803 : 88047295 : ret = __handle_mm_fault(mm, vma, address, flags);
3804 : :
3805 : : if (flags & FAULT_FLAG_USER) {
3806 : : mem_cgroup_oom_disable();
3807 : : /*
3808 : : * The task may have entered a memcg OOM situation but
3809 : : * if the allocation error was handled gracefully (no
3810 : : * VM_FAULT_OOM), there is no need to kill anything.
3811 : : * Just clean up the OOM state peacefully.
3812 : : */
3813 : : if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM))
3814 : : mem_cgroup_oom_synchronize(false);
3815 : : }
3816 : :
3817 : 88031140 : return ret;
3818 : : }
3819 : :
3820 : : #ifndef __PAGETABLE_PUD_FOLDED
3821 : : /*
3822 : : * Allocate page upper directory.
3823 : : * We've already handled the fast-path in-line.
3824 : : */
3825 : : int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
3826 : : {
3827 : : pud_t *new = pud_alloc_one(mm, address);
3828 : : if (!new)
3829 : : return -ENOMEM;
3830 : :
3831 : : smp_wmb(); /* See comment in __pte_alloc */
3832 : :
3833 : : spin_lock(&mm->page_table_lock);
3834 : : if (pgd_present(*pgd)) /* Another has populated it */
3835 : : pud_free(mm, new);
3836 : : else
3837 : : pgd_populate(mm, pgd, new);
3838 : : spin_unlock(&mm->page_table_lock);
3839 : : return 0;
3840 : : }
3841 : : #endif /* __PAGETABLE_PUD_FOLDED */
3842 : :
3843 : : #ifndef __PAGETABLE_PMD_FOLDED
3844 : : /*
3845 : : * Allocate page middle directory.
3846 : : * We've already handled the fast-path in-line.
3847 : : */
3848 : 0 : int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
3849 : : {
3850 : 0 : pmd_t *new = pmd_alloc_one(mm, address);
3851 : : if (!new)
3852 : : return -ENOMEM;
3853 : :
3854 : : smp_wmb(); /* See comment in __pte_alloc */
3855 : :
3856 : : spin_lock(&mm->page_table_lock);
3857 : : #ifndef __ARCH_HAS_4LEVEL_HACK
3858 : : if (pud_present(*pud)) /* Another has populated it */
3859 : : pmd_free(mm, new);
3860 : : else
3861 : : pud_populate(mm, pud, new);
3862 : : #else
3863 : : if (pgd_present(*pud)) /* Another has populated it */
3864 : : pmd_free(mm, new);
3865 : : else
3866 : : pgd_populate(mm, pud, new);
3867 : : #endif /* __ARCH_HAS_4LEVEL_HACK */
3868 : : spin_unlock(&mm->page_table_lock);
3869 : : return 0;
3870 : : }
3871 : : #endif /* __PAGETABLE_PMD_FOLDED */
3872 : :
3873 : : #if !defined(__HAVE_ARCH_GATE_AREA)
3874 : :
3875 : : #if defined(AT_SYSINFO_EHDR)
3876 : : static struct vm_area_struct gate_vma;
3877 : :
3878 : : static int __init gate_vma_init(void)
3879 : : {
3880 : : gate_vma.vm_mm = NULL;
3881 : : gate_vma.vm_start = FIXADDR_USER_START;
3882 : : gate_vma.vm_end = FIXADDR_USER_END;
3883 : : gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3884 : : gate_vma.vm_page_prot = __P101;
3885 : :
3886 : : return 0;
3887 : : }
3888 : : __initcall(gate_vma_init);
3889 : : #endif
3890 : :
3891 : : struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
3892 : : {
3893 : : #ifdef AT_SYSINFO_EHDR
3894 : : return &gate_vma;
3895 : : #else
3896 : : return NULL;
3897 : : #endif
3898 : : }
3899 : :
3900 : : int in_gate_area_no_mm(unsigned long addr)
3901 : : {
3902 : : #ifdef AT_SYSINFO_EHDR
3903 : : if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3904 : : return 1;
3905 : : #endif
3906 : : return 0;
3907 : : }
3908 : :
3909 : : #endif /* __HAVE_ARCH_GATE_AREA */
3910 : :
3911 : 0 : static int __follow_pte(struct mm_struct *mm, unsigned long address,
3912 : : pte_t **ptepp, spinlock_t **ptlp)
3913 : : {
3914 : : pgd_t *pgd;
3915 : : pud_t *pud;
3916 : : pmd_t *pmd;
3917 : : pte_t *ptep;
3918 : :
3919 : 0 : pgd = pgd_offset(mm, address);
3920 : : if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3921 : : goto out;
3922 : :
3923 : : pud = pud_offset(pgd, address);
3924 : : if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3925 : : goto out;
3926 : :
3927 : : pmd = pmd_offset(pud, address);
3928 : : VM_BUG_ON(pmd_trans_huge(*pmd));
3929 [ # # ][ # # ]: 0 : if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3930 : : goto out;
3931 : :
3932 : : /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3933 : : if (pmd_huge(*pmd))
3934 : : goto out;
3935 : :
3936 : 0 : ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3937 [ # # ]: 0 : if (!ptep)
3938 : : goto out;
3939 [ # # ]: 0 : if (!pte_present(*ptep))
3940 : : goto unlock;
3941 : 0 : *ptepp = ptep;
3942 : : return 0;
3943 : : unlock:
3944 : 0 : pte_unmap_unlock(ptep, *ptlp);
3945 : : out:
3946 : : return -EINVAL;
3947 : : }
3948 : :
3949 : : static inline int follow_pte(struct mm_struct *mm, unsigned long address,
3950 : : pte_t **ptepp, spinlock_t **ptlp)
3951 : : {
3952 : : int res;
3953 : :
3954 : : /* (void) is needed to make gcc happy */
3955 : 0 : (void) __cond_lock(*ptlp,
3956 : : !(res = __follow_pte(mm, address, ptepp, ptlp)));
3957 : : return res;
3958 : : }
3959 : :
3960 : : /**
3961 : : * follow_pfn - look up PFN at a user virtual address
3962 : : * @vma: memory mapping
3963 : : * @address: user virtual address
3964 : : * @pfn: location to store found PFN
3965 : : *
3966 : : * Only IO mappings and raw PFN mappings are allowed.
3967 : : *
3968 : : * Returns zero and the pfn at @pfn on success, -ve otherwise.
3969 : : */
3970 : 0 : int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3971 : : unsigned long *pfn)
3972 : : {
3973 : : int ret = -EINVAL;
3974 : : spinlock_t *ptl;
3975 : : pte_t *ptep;
3976 : :
3977 [ # # ]: 0 : if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3978 : : return ret;
3979 : :
3980 : 0 : ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3981 [ # # ]: 0 : if (ret)
3982 : : return ret;
3983 : 0 : *pfn = pte_pfn(*ptep);
3984 : 0 : pte_unmap_unlock(ptep, ptl);
3985 : 0 : return 0;
3986 : : }
3987 : : EXPORT_SYMBOL(follow_pfn);
3988 : :
3989 : : #ifdef CONFIG_HAVE_IOREMAP_PROT
3990 : : int follow_phys(struct vm_area_struct *vma,
3991 : : unsigned long address, unsigned int flags,
3992 : : unsigned long *prot, resource_size_t *phys)
3993 : : {
3994 : : int ret = -EINVAL;
3995 : : pte_t *ptep, pte;
3996 : : spinlock_t *ptl;
3997 : :
3998 : : if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3999 : : goto out;
4000 : :
4001 : : if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
4002 : : goto out;
4003 : : pte = *ptep;
4004 : :
4005 : : if ((flags & FOLL_WRITE) && !pte_write(pte))
4006 : : goto unlock;
4007 : :
4008 : : *prot = pgprot_val(pte_pgprot(pte));
4009 : : *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
4010 : :
4011 : : ret = 0;
4012 : : unlock:
4013 : : pte_unmap_unlock(ptep, ptl);
4014 : : out:
4015 : : return ret;
4016 : : }
4017 : :
4018 : : int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
4019 : : void *buf, int len, int write)
4020 : : {
4021 : : resource_size_t phys_addr;
4022 : : unsigned long prot = 0;
4023 : : void __iomem *maddr;
4024 : : int offset = addr & (PAGE_SIZE-1);
4025 : :
4026 : : if (follow_phys(vma, addr, write, &prot, &phys_addr))
4027 : : return -EINVAL;
4028 : :
4029 : : maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
4030 : : if (write)
4031 : : memcpy_toio(maddr + offset, buf, len);
4032 : : else
4033 : : memcpy_fromio(buf, maddr + offset, len);
4034 : : iounmap(maddr);
4035 : :
4036 : : return len;
4037 : : }
4038 : : EXPORT_SYMBOL_GPL(generic_access_phys);
4039 : : #endif
4040 : :
4041 : : /*
4042 : : * Access another process' address space as given in mm. If non-NULL, use the
4043 : : * given task for page fault accounting.
4044 : : */
4045 : 0 : static int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
4046 : : unsigned long addr, void *buf, int len, int write)
4047 : : {
4048 : : struct vm_area_struct *vma;
4049 : : void *old_buf = buf;
4050 : :
4051 : 64 : down_read(&mm->mmap_sem);
4052 : : /* ignore errors, just check how much was successfully transferred */
4053 [ + + ]: 126 : while (len) {
4054 : : int bytes, ret, offset;
4055 : : void *maddr;
4056 : 64 : struct page *page = NULL;
4057 : :
4058 : 64 : ret = get_user_pages(tsk, mm, addr, 1,
4059 : : write, 1, &page, &vma);
4060 [ + + ]: 64 : if (ret <= 0) {
4061 : : /*
4062 : : * Check if this is a VM_IO | VM_PFNMAP VMA, which
4063 : : * we can access using slightly different code.
4064 : : */
4065 : : #ifdef CONFIG_HAVE_IOREMAP_PROT
4066 : : vma = find_vma(mm, addr);
4067 : : if (!vma || vma->vm_start > addr)
4068 : : break;
4069 : : if (vma->vm_ops && vma->vm_ops->access)
4070 : : ret = vma->vm_ops->access(vma, addr, buf,
4071 : : len, write);
4072 : : if (ret <= 0)
4073 : : #endif
4074 : 2 : break;
4075 : : bytes = ret;
4076 : : } else {
4077 : : bytes = len;
4078 : 62 : offset = addr & (PAGE_SIZE-1);
4079 [ - + ]: 62 : if (bytes > PAGE_SIZE-offset)
4080 : 0 : bytes = PAGE_SIZE-offset;
4081 : :
4082 : 62 : maddr = kmap(page);
4083 [ - + ]: 62 : if (write) {
4084 : 0 : copy_to_user_page(vma, page, addr,
4085 : : maddr + offset, buf, bytes);
4086 : 0 : set_page_dirty_lock(page);
4087 : : } else {
4088 : 62 : copy_from_user_page(vma, page, addr,
4089 : : buf, maddr + offset, bytes);
4090 : : }
4091 : 62 : kunmap(page);
4092 : 62 : page_cache_release(page);
4093 : : }
4094 : 62 : len -= bytes;
4095 : 62 : buf += bytes;
4096 : 62 : addr += bytes;
4097 : : }
4098 : 64 : up_read(&mm->mmap_sem);
4099 : :
4100 : 64 : return buf - old_buf;
4101 : : }
4102 : :
4103 : : /**
4104 : : * access_remote_vm - access another process' address space
4105 : : * @mm: the mm_struct of the target address space
4106 : : * @addr: start address to access
4107 : : * @buf: source or destination buffer
4108 : : * @len: number of bytes to transfer
4109 : : * @write: whether the access is a write
4110 : : *
4111 : : * The caller must hold a reference on @mm.
4112 : : */
4113 : 0 : int access_remote_vm(struct mm_struct *mm, unsigned long addr,
4114 : : void *buf, int len, int write)
4115 : : {
4116 : 6 : return __access_remote_vm(NULL, mm, addr, buf, len, write);
4117 : : }
4118 : :
4119 : : /*
4120 : : * Access another process' address space.
4121 : : * Source/target buffer must be kernel space,
4122 : : * Do not walk the page table directly, use get_user_pages
4123 : : */
4124 : 0 : int access_process_vm(struct task_struct *tsk, unsigned long addr,
4125 : : void *buf, int len, int write)
4126 : : {
4127 : : struct mm_struct *mm;
4128 : : int ret;
4129 : :
4130 : 58 : mm = get_task_mm(tsk);
4131 [ + - ]: 58 : if (!mm)
4132 : : return 0;
4133 : :
4134 : 58 : ret = __access_remote_vm(tsk, mm, addr, buf, len, write);
4135 : 58 : mmput(mm);
4136 : :
4137 : 58 : return ret;
4138 : : }
4139 : :
4140 : : /*
4141 : : * Print the name of a VMA.
4142 : : */
4143 : 0 : void print_vma_addr(char *prefix, unsigned long ip)
4144 : : {
4145 : 0 : struct mm_struct *mm = current->mm;
4146 : : struct vm_area_struct *vma;
4147 : :
4148 : : /*
4149 : : * Do not print if we are in atomic
4150 : : * contexts (in exception stacks, etc.):
4151 : : */
4152 [ # # ]: 0 : if (preempt_count())
4153 : 0 : return;
4154 : :
4155 : 0 : down_read(&mm->mmap_sem);
4156 : 0 : vma = find_vma(mm, ip);
4157 [ # # ][ # # ]: 0 : if (vma && vma->vm_file) {
4158 : : struct file *f = vma->vm_file;
4159 : 0 : char *buf = (char *)__get_free_page(GFP_KERNEL);
4160 [ # # ]: 0 : if (buf) {
4161 : : char *p;
4162 : :
4163 : 0 : p = d_path(&f->f_path, buf, PAGE_SIZE);
4164 [ # # ]: 0 : if (IS_ERR(p))
4165 : : p = "?";
4166 : 0 : printk("%s%s[%lx+%lx]", prefix, kbasename(p),
4167 : : vma->vm_start,
4168 : 0 : vma->vm_end - vma->vm_start);
4169 : 0 : free_page((unsigned long)buf);
4170 : : }
4171 : : }
4172 : 0 : up_read(&mm->mmap_sem);
4173 : : }
4174 : :
4175 : : #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
4176 : : void might_fault(void)
4177 : : {
4178 : : /*
4179 : : * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4180 : : * holding the mmap_sem, this is safe because kernel memory doesn't
4181 : : * get paged out, therefore we'll never actually fault, and the
4182 : : * below annotations will generate false positives.
4183 : : */
4184 : : if (segment_eq(get_fs(), KERNEL_DS))
4185 : : return;
4186 : :
4187 : : /*
4188 : : * it would be nicer only to annotate paths which are not under
4189 : : * pagefault_disable, however that requires a larger audit and
4190 : : * providing helpers like get_user_atomic.
4191 : : */
4192 : : if (in_atomic())
4193 : : return;
4194 : :
4195 : : __might_sleep(__FILE__, __LINE__, 0);
4196 : :
4197 : : if (current->mm)
4198 : : might_lock_read(¤t->mm->mmap_sem);
4199 : : }
4200 : : EXPORT_SYMBOL(might_fault);
4201 : : #endif
4202 : :
4203 : : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4204 : : static void clear_gigantic_page(struct page *page,
4205 : : unsigned long addr,
4206 : : unsigned int pages_per_huge_page)
4207 : : {
4208 : : int i;
4209 : : struct page *p = page;
4210 : :
4211 : : might_sleep();
4212 : : for (i = 0; i < pages_per_huge_page;
4213 : : i++, p = mem_map_next(p, page, i)) {
4214 : : cond_resched();
4215 : : clear_user_highpage(p, addr + i * PAGE_SIZE);
4216 : : }
4217 : : }
4218 : : void clear_huge_page(struct page *page,
4219 : : unsigned long addr, unsigned int pages_per_huge_page)
4220 : : {
4221 : : int i;
4222 : :
4223 : : if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4224 : : clear_gigantic_page(page, addr, pages_per_huge_page);
4225 : : return;
4226 : : }
4227 : :
4228 : : might_sleep();
4229 : : for (i = 0; i < pages_per_huge_page; i++) {
4230 : : cond_resched();
4231 : : clear_user_highpage(page + i, addr + i * PAGE_SIZE);
4232 : : }
4233 : : }
4234 : :
4235 : : static void copy_user_gigantic_page(struct page *dst, struct page *src,
4236 : : unsigned long addr,
4237 : : struct vm_area_struct *vma,
4238 : : unsigned int pages_per_huge_page)
4239 : : {
4240 : : int i;
4241 : : struct page *dst_base = dst;
4242 : : struct page *src_base = src;
4243 : :
4244 : : for (i = 0; i < pages_per_huge_page; ) {
4245 : : cond_resched();
4246 : : copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
4247 : :
4248 : : i++;
4249 : : dst = mem_map_next(dst, dst_base, i);
4250 : : src = mem_map_next(src, src_base, i);
4251 : : }
4252 : : }
4253 : :
4254 : : void copy_user_huge_page(struct page *dst, struct page *src,
4255 : : unsigned long addr, struct vm_area_struct *vma,
4256 : : unsigned int pages_per_huge_page)
4257 : : {
4258 : : int i;
4259 : :
4260 : : if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4261 : : copy_user_gigantic_page(dst, src, addr, vma,
4262 : : pages_per_huge_page);
4263 : : return;
4264 : : }
4265 : :
4266 : : might_sleep();
4267 : : for (i = 0; i < pages_per_huge_page; i++) {
4268 : : cond_resched();
4269 : : copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
4270 : : }
4271 : : }
4272 : : #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
4273 : :
4274 : : #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
4275 : : bool ptlock_alloc(struct page *page)
4276 : : {
4277 : : spinlock_t *ptl;
4278 : :
4279 : : ptl = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
4280 : : if (!ptl)
4281 : : return false;
4282 : : page->ptl = ptl;
4283 : : return true;
4284 : : }
4285 : :
4286 : : void ptlock_free(struct page *page)
4287 : : {
4288 : : kfree(page->ptl);
4289 : : }
4290 : : #endif
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