Branch data Line data Source code
1 : : // SPDX-License-Identifier: GPL-2.0-only
2 : : /*
3 : : * linux/mm/memory.c
4 : : *
5 : : * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
6 : : */
7 : :
8 : : /*
9 : : * demand-loading started 01.12.91 - seems it is high on the list of
10 : : * things wanted, and it should be easy to implement. - Linus
11 : : */
12 : :
13 : : /*
14 : : * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
15 : : * pages started 02.12.91, seems to work. - Linus.
16 : : *
17 : : * Tested sharing by executing about 30 /bin/sh: under the old kernel it
18 : : * would have taken more than the 6M I have free, but it worked well as
19 : : * far as I could see.
20 : : *
21 : : * Also corrected some "invalidate()"s - I wasn't doing enough of them.
22 : : */
23 : :
24 : : /*
25 : : * Real VM (paging to/from disk) started 18.12.91. Much more work and
26 : : * thought has to go into this. Oh, well..
27 : : * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
28 : : * Found it. Everything seems to work now.
29 : : * 20.12.91 - Ok, making the swap-device changeable like the root.
30 : : */
31 : :
32 : : /*
33 : : * 05.04.94 - Multi-page memory management added for v1.1.
34 : : * Idea by Alex Bligh (alex@cconcepts.co.uk)
35 : : *
36 : : * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
37 : : * (Gerhard.Wichert@pdb.siemens.de)
38 : : *
39 : : * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
40 : : */
41 : :
42 : : #include <linux/kernel_stat.h>
43 : : #include <linux/mm.h>
44 : : #include <linux/sched/mm.h>
45 : : #include <linux/sched/coredump.h>
46 : : #include <linux/sched/numa_balancing.h>
47 : : #include <linux/sched/task.h>
48 : : #include <linux/hugetlb.h>
49 : : #include <linux/mman.h>
50 : : #include <linux/swap.h>
51 : : #include <linux/highmem.h>
52 : : #include <linux/pagemap.h>
53 : : #include <linux/memremap.h>
54 : : #include <linux/ksm.h>
55 : : #include <linux/rmap.h>
56 : : #include <linux/export.h>
57 : : #include <linux/delayacct.h>
58 : : #include <linux/init.h>
59 : : #include <linux/pfn_t.h>
60 : : #include <linux/writeback.h>
61 : : #include <linux/memcontrol.h>
62 : : #include <linux/mmu_notifier.h>
63 : : #include <linux/swapops.h>
64 : : #include <linux/elf.h>
65 : : #include <linux/gfp.h>
66 : : #include <linux/migrate.h>
67 : : #include <linux/string.h>
68 : : #include <linux/dma-debug.h>
69 : : #include <linux/debugfs.h>
70 : : #include <linux/userfaultfd_k.h>
71 : : #include <linux/dax.h>
72 : : #include <linux/oom.h>
73 : : #include <linux/numa.h>
74 : :
75 : : #include <trace/events/kmem.h>
76 : :
77 : : #include <asm/io.h>
78 : : #include <asm/mmu_context.h>
79 : : #include <asm/pgalloc.h>
80 : : #include <linux/uaccess.h>
81 : : #include <asm/tlb.h>
82 : : #include <asm/tlbflush.h>
83 : : #include <asm/pgtable.h>
84 : :
85 : : #include "internal.h"
86 : :
87 : : #if defined(LAST_CPUPID_NOT_IN_PAGE_FLAGS) && !defined(CONFIG_COMPILE_TEST)
88 : : #warning Unfortunate NUMA and NUMA Balancing config, growing page-frame for last_cpupid.
89 : : #endif
90 : :
91 : : #ifndef CONFIG_NEED_MULTIPLE_NODES
92 : : /* use the per-pgdat data instead for discontigmem - mbligh */
93 : : unsigned long max_mapnr;
94 : : EXPORT_SYMBOL(max_mapnr);
95 : :
96 : : struct page *mem_map;
97 : : EXPORT_SYMBOL(mem_map);
98 : : #endif
99 : :
100 : : /*
101 : : * A number of key systems in x86 including ioremap() rely on the assumption
102 : : * that high_memory defines the upper bound on direct map memory, then end
103 : : * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
104 : : * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
105 : : * and ZONE_HIGHMEM.
106 : : */
107 : : void *high_memory;
108 : : EXPORT_SYMBOL(high_memory);
109 : :
110 : : /*
111 : : * Randomize the address space (stacks, mmaps, brk, etc.).
112 : : *
113 : : * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
114 : : * as ancient (libc5 based) binaries can segfault. )
115 : : */
116 : : int randomize_va_space __read_mostly =
117 : : #ifdef CONFIG_COMPAT_BRK
118 : : 1;
119 : : #else
120 : : 2;
121 : : #endif
122 : :
123 : : #ifndef arch_faults_on_old_pte
124 : : static inline bool arch_faults_on_old_pte(void)
125 : : {
126 : : /*
127 : : * Those arches which don't have hw access flag feature need to
128 : : * implement their own helper. By default, "true" means pagefault
129 : : * will be hit on old pte.
130 : : */
131 : : return true;
132 : : }
133 : : #endif
134 : :
135 : 0 : static int __init disable_randmaps(char *s)
136 : : {
137 : 0 : randomize_va_space = 0;
138 : 0 : return 1;
139 : : }
140 : : __setup("norandmaps", disable_randmaps);
141 : :
142 : : unsigned long zero_pfn __read_mostly;
143 : : EXPORT_SYMBOL(zero_pfn);
144 : :
145 : : unsigned long highest_memmap_pfn __read_mostly;
146 : :
147 : : /*
148 : : * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
149 : : */
150 : 11 : static int __init init_zero_pfn(void)
151 : : {
152 [ - + ]: 11 : zero_pfn = page_to_pfn(ZERO_PAGE(0));
153 : 11 : return 0;
154 : : }
155 : : core_initcall(init_zero_pfn);
156 : :
157 : 1003016 : void mm_trace_rss_stat(struct mm_struct *mm, int member, long count)
158 : : {
159 : 1003016 : trace_rss_stat(mm, member, count);
160 : 17798 : }
161 : :
162 : : #if defined(SPLIT_RSS_COUNTING)
163 : :
164 : 142382 : void sync_mm_rss(struct mm_struct *mm)
165 : : {
166 : 142382 : int i;
167 : :
168 [ + + ]: 711910 : for (i = 0; i < NR_MM_COUNTERS; i++) {
169 [ + + ]: 569528 : if (current->rss_stat.count[i]) {
170 : 130157 : add_mm_counter(mm, i, current->rss_stat.count[i]);
171 : 130157 : current->rss_stat.count[i] = 0;
172 : : }
173 : : }
174 : 142382 : current->rss_stat.events = 0;
175 : 142382 : }
176 : :
177 : 6445540 : static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
178 : : {
179 [ + + ]: 6445540 : struct task_struct *task = current;
180 : :
181 [ + + ]: 6445540 : if (likely(task->mm == mm))
182 : 6436586 : task->rss_stat.count[member] += val;
183 : : else
184 : 8954 : add_mm_counter(mm, member, val);
185 : 6445540 : }
186 : : #define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
187 : : #define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
188 : :
189 : : /* sync counter once per 64 page faults */
190 : : #define TASK_RSS_EVENTS_THRESH (64)
191 : 1155182 : static void check_sync_rss_stat(struct task_struct *task)
192 : : {
193 [ + - ]: 1155182 : if (unlikely(task != current))
194 : : return;
195 [ + + ]: 1155182 : if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
196 : 3798 : sync_mm_rss(task->mm);
197 : : }
198 : : #else /* SPLIT_RSS_COUNTING */
199 : :
200 : : #define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
201 : : #define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
202 : :
203 : : static void check_sync_rss_stat(struct task_struct *task)
204 : : {
205 : : }
206 : :
207 : : #endif /* SPLIT_RSS_COUNTING */
208 : :
209 : : /*
210 : : * Note: this doesn't free the actual pages themselves. That
211 : : * has been handled earlier when unmapping all the memory regions.
212 : : */
213 : 128805 : static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
214 : : unsigned long addr)
215 : : {
216 [ + - ]: 128805 : pgtable_t token = pmd_pgtable(*pmd);
217 : 128805 : pmd_clear(pmd);
218 : 128805 : pte_free_tlb(tlb, token, addr);
219 : 128805 : mm_dec_nr_ptes(tlb->mm);
220 : 128805 : }
221 : :
222 : 78926 : static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
223 : : unsigned long addr, unsigned long end,
224 : : unsigned long floor, unsigned long ceiling)
225 : : {
226 : 78926 : pmd_t *pmd;
227 : 78926 : unsigned long next;
228 : 78926 : unsigned long start;
229 : :
230 : 78926 : start = addr;
231 [ + - ]: 78926 : pmd = pmd_offset(pud, addr);
232 : 134361 : do {
233 [ + + ]: 134361 : next = pmd_addr_end(addr, end);
234 [ + + ]: 134361 : if (pmd_none_or_clear_bad(pmd))
235 : 5556 : continue;
236 : 128805 : free_pte_range(tlb, pmd, addr);
237 [ + + ]: 134361 : } while (pmd++, addr = next, addr != end);
238 : :
239 : 78926 : start &= PUD_MASK;
240 [ + + ]: 78926 : if (start < floor)
241 : : return;
242 [ + + ]: 78338 : if (ceiling) {
243 : 52190 : ceiling &= PUD_MASK;
244 [ + - ]: 52190 : if (!ceiling)
245 : : return;
246 : : }
247 [ + + ]: 78338 : if (end - 1 > ceiling - 1)
248 : : return;
249 : :
250 [ + - ]: 61857 : pmd = pmd_offset(pud, start);
251 : 61857 : pud_clear(pud);
252 : 61857 : pmd_free_tlb(tlb, pmd, start);
253 : 61857 : mm_dec_nr_pmds(tlb->mm);
254 : : }
255 : :
256 : 79246 : static inline void free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
257 : : unsigned long addr, unsigned long end,
258 : : unsigned long floor, unsigned long ceiling)
259 : : {
260 : 79246 : pud_t *pud;
261 : 79246 : unsigned long next;
262 : 79246 : unsigned long start;
263 : :
264 : 79246 : start = addr;
265 : 79246 : pud = pud_offset(p4d, addr);
266 : 79284 : do {
267 [ + + ]: 79284 : next = pud_addr_end(addr, end);
268 [ + + ]: 79284 : if (pud_none_or_clear_bad(pud))
269 : 358 : continue;
270 : 78926 : free_pmd_range(tlb, pud, addr, next, floor, ceiling);
271 [ + + ]: 79284 : } while (pud++, addr = next, addr != end);
272 : :
273 : 79246 : start &= P4D_MASK;
274 [ + + ]: 79246 : if (start < floor)
275 : : return;
276 [ + + ]: 69888 : if (ceiling) {
277 : 52156 : ceiling &= P4D_MASK;
278 [ + - ]: 52156 : if (!ceiling)
279 : : return;
280 : : }
281 [ + + ]: 69888 : if (end - 1 > ceiling - 1)
282 : : return;
283 : :
284 : 44755 : pud = pud_offset(p4d, start);
285 : 44755 : p4d_clear(p4d);
286 : 44755 : pud_free_tlb(tlb, pud, start);
287 : 44755 : mm_dec_nr_puds(tlb->mm);
288 : : }
289 : :
290 : 80045 : static inline void free_p4d_range(struct mmu_gather *tlb, pgd_t *pgd,
291 : : unsigned long addr, unsigned long end,
292 : : unsigned long floor, unsigned long ceiling)
293 : : {
294 : 80045 : p4d_t *p4d;
295 : 80045 : unsigned long next;
296 : 80045 : unsigned long start;
297 : :
298 : 80045 : start = addr;
299 : 80045 : p4d = p4d_offset(pgd, addr);
300 : 80045 : do {
301 [ - + ]: 80045 : next = p4d_addr_end(addr, end);
302 [ + + ]: 80045 : if (p4d_none_or_clear_bad(p4d))
303 : 799 : continue;
304 : 79246 : free_pud_range(tlb, p4d, addr, next, floor, ceiling);
305 [ - + ]: 80045 : } while (p4d++, addr = next, addr != end);
306 : :
307 : 80045 : start &= PGDIR_MASK;
308 [ + + ]: 80045 : if (start < floor)
309 : : return;
310 [ + + ]: 69888 : if (ceiling) {
311 : 52156 : ceiling &= PGDIR_MASK;
312 [ + - ]: 52156 : if (!ceiling)
313 : : return;
314 : : }
315 [ + + ]: 69888 : if (end - 1 > ceiling - 1)
316 : : return;
317 : :
318 : 44755 : p4d = p4d_offset(pgd, start);
319 [ - - + ]: 44755 : pgd_clear(pgd);
320 : 44755 : p4d_free_tlb(tlb, p4d, start);
321 : : }
322 : :
323 : : /*
324 : : * This function frees user-level page tables of a process.
325 : : */
326 : 211384 : void free_pgd_range(struct mmu_gather *tlb,
327 : : unsigned long addr, unsigned long end,
328 : : unsigned long floor, unsigned long ceiling)
329 : : {
330 : 211384 : pgd_t *pgd;
331 : 211384 : unsigned long next;
332 : :
333 : : /*
334 : : * The next few lines have given us lots of grief...
335 : : *
336 : : * Why are we testing PMD* at this top level? Because often
337 : : * there will be no work to do at all, and we'd prefer not to
338 : : * go all the way down to the bottom just to discover that.
339 : : *
340 : : * Why all these "- 1"s? Because 0 represents both the bottom
341 : : * of the address space and the top of it (using -1 for the
342 : : * top wouldn't help much: the masks would do the wrong thing).
343 : : * The rule is that addr 0 and floor 0 refer to the bottom of
344 : : * the address space, but end 0 and ceiling 0 refer to the top
345 : : * Comparisons need to use "end - 1" and "ceiling - 1" (though
346 : : * that end 0 case should be mythical).
347 : : *
348 : : * Wherever addr is brought up or ceiling brought down, we must
349 : : * be careful to reject "the opposite 0" before it confuses the
350 : : * subsequent tests. But what about where end is brought down
351 : : * by PMD_SIZE below? no, end can't go down to 0 there.
352 : : *
353 : : * Whereas we round start (addr) and ceiling down, by different
354 : : * masks at different levels, in order to test whether a table
355 : : * now has no other vmas using it, so can be freed, we don't
356 : : * bother to round floor or end up - the tests don't need that.
357 : : */
358 : :
359 : 211384 : addr &= PMD_MASK;
360 [ + + ]: 211384 : if (addr < floor) {
361 : 129676 : addr += PMD_SIZE;
362 [ + - ]: 129676 : if (!addr)
363 : : return;
364 : : }
365 [ + + ]: 211384 : if (ceiling) {
366 : 184698 : ceiling &= PMD_MASK;
367 [ + - ]: 184698 : if (!ceiling)
368 : : return;
369 : : }
370 [ + + ]: 211384 : if (end - 1 > ceiling - 1)
371 : 114312 : end -= PMD_SIZE;
372 [ + + ]: 211384 : if (addr > end - 1)
373 : : return;
374 : : /*
375 : : * We add page table cache pages with PAGE_SIZE,
376 : : * (see pte_free_tlb()), flush the tlb if we need
377 : : */
378 : 80045 : tlb_change_page_size(tlb, PAGE_SIZE);
379 : 80045 : pgd = pgd_offset(tlb->mm, addr);
380 : 80045 : do {
381 [ + - ]: 80045 : next = pgd_addr_end(addr, end);
382 [ - + ]: 80045 : if (pgd_none_or_clear_bad(pgd))
383 : 0 : continue;
384 : 80045 : free_p4d_range(tlb, pgd, addr, next, floor, ceiling);
385 [ - + ]: 80045 : } while (pgd++, addr = next, addr != end);
386 : : }
387 : :
388 : 150505 : void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
389 : : unsigned long floor, unsigned long ceiling)
390 : : {
391 [ + + ]: 352935 : while (vma) {
392 : 202430 : struct vm_area_struct *next = vma->vm_next;
393 : 202430 : unsigned long addr = vma->vm_start;
394 : :
395 : : /*
396 : : * Hide vma from rmap and truncate_pagecache before freeing
397 : : * pgtables
398 : : */
399 : 202430 : unlink_anon_vmas(vma);
400 : 202430 : unlink_file_vma(vma);
401 : :
402 [ + - ]: 202430 : if (is_vm_hugetlb_page(vma)) {
403 [ # # ]: 0 : hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
404 : : floor, next ? next->vm_start : ceiling);
405 : : } else {
406 : : /*
407 : : * Optimization: gather nearby vmas into one call down
408 : : */
409 [ + + + + ]: 1029477 : while (next && next->vm_start <= vma->vm_end + PMD_SIZE
410 [ + - ]: 827047 : && !is_vm_hugetlb_page(next)) {
411 : 827047 : vma = next;
412 : 827047 : next = vma->vm_next;
413 : 827047 : unlink_anon_vmas(vma);
414 : 827047 : unlink_file_vma(vma);
415 : : }
416 [ + + ]: 202430 : free_pgd_range(tlb, addr, vma->vm_end,
417 : : floor, next ? next->vm_start : ceiling);
418 : : }
419 : : vma = next;
420 : : }
421 : 150505 : }
422 : :
423 : 90551 : int __pte_alloc(struct mm_struct *mm, pmd_t *pmd)
424 : : {
425 : 90551 : spinlock_t *ptl;
426 : 90551 : pgtable_t new = pte_alloc_one(mm);
427 [ + - ]: 90551 : if (!new)
428 : : return -ENOMEM;
429 : :
430 : : /*
431 : : * Ensure all pte setup (eg. pte page lock and page clearing) are
432 : : * visible before the pte is made visible to other CPUs by being
433 : : * put into page tables.
434 : : *
435 : : * The other side of the story is the pointer chasing in the page
436 : : * table walking code (when walking the page table without locking;
437 : : * ie. most of the time). Fortunately, these data accesses consist
438 : : * of a chain of data-dependent loads, meaning most CPUs (alpha
439 : : * being the notable exception) will already guarantee loads are
440 : : * seen in-order. See the alpha page table accessors for the
441 : : * smp_read_barrier_depends() barriers in page table walking code.
442 : : */
443 : 90551 : smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
444 : :
445 : 90551 : ptl = pmd_lock(mm, pmd);
446 [ + - ]: 90551 : if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
447 : 90551 : mm_inc_nr_ptes(mm);
448 : 90551 : pmd_populate(mm, pmd, new);
449 : 90551 : new = NULL;
450 : : }
451 : 90551 : spin_unlock(ptl);
452 [ - + ]: 90551 : if (new)
453 : 0 : pte_free(mm, new);
454 : : return 0;
455 : : }
456 : :
457 : 220 : int __pte_alloc_kernel(pmd_t *pmd)
458 : : {
459 : 220 : pte_t *new = pte_alloc_one_kernel(&init_mm);
460 [ + - ]: 220 : if (!new)
461 : : return -ENOMEM;
462 : :
463 : 220 : smp_wmb(); /* See comment in __pte_alloc */
464 : :
465 : 220 : spin_lock(&init_mm.page_table_lock);
466 [ + - ]: 220 : if (likely(pmd_none(*pmd))) { /* Has another populated it ? */
467 [ + - ]: 220 : pmd_populate_kernel(&init_mm, pmd, new);
468 : 220 : new = NULL;
469 : : }
470 : 220 : spin_unlock(&init_mm.page_table_lock);
471 [ - + ]: 220 : if (new)
472 : 0 : pte_free_kernel(&init_mm, new);
473 : : return 0;
474 : : }
475 : :
476 : 1280569 : static inline void init_rss_vec(int *rss)
477 : : {
478 : 1280569 : memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
479 : : }
480 : :
481 : 1280569 : static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
482 : : {
483 : 1280569 : int i;
484 : :
485 [ + + ]: 1280569 : if (current->mm == mm)
486 : 112019 : sync_mm_rss(mm);
487 [ + + ]: 6402845 : for (i = 0; i < NR_MM_COUNTERS; i++)
488 [ + + ]: 5122276 : if (rss[i])
489 : 846107 : add_mm_counter(mm, i, rss[i]);
490 : 1280569 : }
491 : :
492 : : /*
493 : : * This function is called to print an error when a bad pte
494 : : * is found. For example, we might have a PFN-mapped pte in
495 : : * a region that doesn't allow it.
496 : : *
497 : : * The calling function must still handle the error.
498 : : */
499 : 0 : static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
500 : : pte_t pte, struct page *page)
501 : : {
502 : 0 : pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
503 : 0 : p4d_t *p4d = p4d_offset(pgd, addr);
504 [ # # ]: 0 : pud_t *pud = pud_offset(p4d, addr);
505 [ # # ]: 0 : pmd_t *pmd = pmd_offset(pud, addr);
506 : 0 : struct address_space *mapping;
507 : 0 : pgoff_t index;
508 : 0 : static unsigned long resume;
509 : 0 : static unsigned long nr_shown;
510 : 0 : static unsigned long nr_unshown;
511 : :
512 : : /*
513 : : * Allow a burst of 60 reports, then keep quiet for that minute;
514 : : * or allow a steady drip of one report per second.
515 : : */
516 [ # # ]: 0 : if (nr_shown == 60) {
517 [ # # ]: 0 : if (time_before(jiffies, resume)) {
518 : 0 : nr_unshown++;
519 : 0 : return;
520 : : }
521 [ # # ]: 0 : if (nr_unshown) {
522 : 0 : pr_alert("BUG: Bad page map: %lu messages suppressed\n",
523 : : nr_unshown);
524 : 0 : nr_unshown = 0;
525 : : }
526 : 0 : nr_shown = 0;
527 : : }
528 [ # # ]: 0 : if (nr_shown++ == 0)
529 : 0 : resume = jiffies + 60 * HZ;
530 : :
531 [ # # ]: 0 : mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
532 : 0 : index = linear_page_index(vma, addr);
533 : :
534 : 0 : pr_alert("BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
535 : : current->comm,
536 : : (long long)pte_val(pte), (long long)pmd_val(*pmd));
537 [ # # ]: 0 : if (page)
538 : 0 : dump_page(page, "bad pte");
539 : 0 : pr_alert("addr:%px vm_flags:%08lx anon_vma:%px mapping:%px index:%lx\n",
540 : : (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
541 [ # # # # : 0 : pr_alert("file:%pD fault:%ps mmap:%ps readpage:%ps\n",
# # ]
542 : : vma->vm_file,
543 : : vma->vm_ops ? vma->vm_ops->fault : NULL,
544 : : vma->vm_file ? vma->vm_file->f_op->mmap : NULL,
545 : : mapping ? mapping->a_ops->readpage : NULL);
546 : 0 : dump_stack();
547 : 0 : add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
548 : : }
549 : :
550 : : /*
551 : : * vm_normal_page -- This function gets the "struct page" associated with a pte.
552 : : *
553 : : * "Special" mappings do not wish to be associated with a "struct page" (either
554 : : * it doesn't exist, or it exists but they don't want to touch it). In this
555 : : * case, NULL is returned here. "Normal" mappings do have a struct page.
556 : : *
557 : : * There are 2 broad cases. Firstly, an architecture may define a pte_special()
558 : : * pte bit, in which case this function is trivial. Secondly, an architecture
559 : : * may not have a spare pte bit, which requires a more complicated scheme,
560 : : * described below.
561 : : *
562 : : * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
563 : : * special mapping (even if there are underlying and valid "struct pages").
564 : : * COWed pages of a VM_PFNMAP are always normal.
565 : : *
566 : : * The way we recognize COWed pages within VM_PFNMAP mappings is through the
567 : : * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
568 : : * set, and the vm_pgoff will point to the first PFN mapped: thus every special
569 : : * mapping will always honor the rule
570 : : *
571 : : * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
572 : : *
573 : : * And for normal mappings this is false.
574 : : *
575 : : * This restricts such mappings to be a linear translation from virtual address
576 : : * to pfn. To get around this restriction, we allow arbitrary mappings so long
577 : : * as the vma is not a COW mapping; in that case, we know that all ptes are
578 : : * special (because none can have been COWed).
579 : : *
580 : : *
581 : : * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
582 : : *
583 : : * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
584 : : * page" backing, however the difference is that _all_ pages with a struct
585 : : * page (that is, those where pfn_valid is true) are refcounted and considered
586 : : * normal pages by the VM. The disadvantage is that pages are refcounted
587 : : * (which can be slower and simply not an option for some PFNMAP users). The
588 : : * advantage is that we don't have to follow the strict linearity rule of
589 : : * PFNMAP mappings in order to support COWable mappings.
590 : : *
591 : : */
592 : 7641846 : struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
593 : : pte_t pte)
594 : : {
595 [ + - ]: 7641846 : unsigned long pfn = pte_pfn(pte);
596 : :
597 : 7641846 : if (IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL)) {
598 [ + + ]: 7641846 : if (likely(!pte_special(pte)))
599 : 7606927 : goto check_pfn;
600 [ + + - + ]: 34919 : if (vma->vm_ops && vma->vm_ops->find_special_page)
601 : 0 : return vma->vm_ops->find_special_page(vma, addr);
602 [ + + ]: 34919 : if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
603 : : return NULL;
604 [ - + ]: 10153 : if (is_zero_pfn(pfn))
605 : : return NULL;
606 [ # # ]: 0 : if (pte_devmap(pte))
607 : : return NULL;
608 : :
609 : 0 : print_bad_pte(vma, addr, pte, NULL);
610 : 0 : return NULL;
611 : : }
612 : :
613 : : /* !CONFIG_ARCH_HAS_PTE_SPECIAL case follows: */
614 : :
615 : : if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
616 : : if (vma->vm_flags & VM_MIXEDMAP) {
617 : : if (!pfn_valid(pfn))
618 : : return NULL;
619 : : goto out;
620 : : } else {
621 : : unsigned long off;
622 : : off = (addr - vma->vm_start) >> PAGE_SHIFT;
623 : : if (pfn == vma->vm_pgoff + off)
624 : : return NULL;
625 : : if (!is_cow_mapping(vma->vm_flags))
626 : : return NULL;
627 : : }
628 : : }
629 : :
630 : : if (is_zero_pfn(pfn))
631 : : return NULL;
632 : :
633 : : check_pfn:
634 [ - + ]: 7606927 : if (unlikely(pfn > highest_memmap_pfn)) {
635 : 0 : print_bad_pte(vma, addr, pte, NULL);
636 : 0 : return NULL;
637 : : }
638 : :
639 : : /*
640 : : * NOTE! We still have PageReserved() pages in the page tables.
641 : : * eg. VDSO mappings can cause them to exist.
642 : : */
643 : 7606927 : out:
644 : 7606927 : return pfn_to_page(pfn);
645 : : }
646 : :
647 : : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
648 : : struct page *vm_normal_page_pmd(struct vm_area_struct *vma, unsigned long addr,
649 : : pmd_t pmd)
650 : : {
651 : : unsigned long pfn = pmd_pfn(pmd);
652 : :
653 : : /*
654 : : * There is no pmd_special() but there may be special pmds, e.g.
655 : : * in a direct-access (dax) mapping, so let's just replicate the
656 : : * !CONFIG_ARCH_HAS_PTE_SPECIAL case from vm_normal_page() here.
657 : : */
658 : : if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
659 : : if (vma->vm_flags & VM_MIXEDMAP) {
660 : : if (!pfn_valid(pfn))
661 : : return NULL;
662 : : goto out;
663 : : } else {
664 : : unsigned long off;
665 : : off = (addr - vma->vm_start) >> PAGE_SHIFT;
666 : : if (pfn == vma->vm_pgoff + off)
667 : : return NULL;
668 : : if (!is_cow_mapping(vma->vm_flags))
669 : : return NULL;
670 : : }
671 : : }
672 : :
673 : : if (pmd_devmap(pmd))
674 : : return NULL;
675 : : if (is_huge_zero_pmd(pmd))
676 : : return NULL;
677 : : if (unlikely(pfn > highest_memmap_pfn))
678 : : return NULL;
679 : :
680 : : /*
681 : : * NOTE! We still have PageReserved() pages in the page tables.
682 : : * eg. VDSO mappings can cause them to exist.
683 : : */
684 : : out:
685 : : return pfn_to_page(pfn);
686 : : }
687 : : #endif
688 : :
689 : : /*
690 : : * copy one vm_area from one task to the other. Assumes the page tables
691 : : * already present in the new task to be cleared in the whole range
692 : : * covered by this vma.
693 : : */
694 : :
695 : : static inline unsigned long
696 : 648069 : copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
697 : : pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
698 : : unsigned long addr, int *rss)
699 : : {
700 : 648069 : unsigned long vm_flags = vma->vm_flags;
701 : 648069 : pte_t pte = *src_pte;
702 : 648069 : struct page *page;
703 : :
704 : : /* pte contains position in swap or file, so copy. */
705 [ - + ]: 648069 : if (unlikely(!pte_present(pte))) {
706 [ # # ]: 0 : swp_entry_t entry = pte_to_swp_entry(pte);
707 : :
708 [ # # ]: 0 : if (likely(!non_swap_entry(entry))) {
709 [ # # ]: 0 : if (swap_duplicate(entry) < 0)
710 : : return entry.val;
711 : :
712 : : /* make sure dst_mm is on swapoff's mmlist. */
713 [ # # ]: 0 : if (unlikely(list_empty(&dst_mm->mmlist))) {
714 : 0 : spin_lock(&mmlist_lock);
715 [ # # ]: 0 : if (list_empty(&dst_mm->mmlist))
716 : 0 : list_add(&dst_mm->mmlist,
717 : : &src_mm->mmlist);
718 : 0 : spin_unlock(&mmlist_lock);
719 : : }
720 : 0 : rss[MM_SWAPENTS]++;
721 [ # # ]: 0 : } else if (is_migration_entry(entry)) {
722 : 0 : page = migration_entry_to_page(entry);
723 : :
724 : 0 : rss[mm_counter(page)]++;
725 : :
726 [ # # # # ]: 0 : if (is_write_migration_entry(entry) &&
727 : : is_cow_mapping(vm_flags)) {
728 : : /*
729 : : * COW mappings require pages in both
730 : : * parent and child to be set to read.
731 : : */
732 : 0 : make_migration_entry_read(&entry);
733 : 0 : pte = swp_entry_to_pte(entry);
734 : 0 : if (pte_swp_soft_dirty(*src_pte))
735 : : pte = pte_swp_mksoft_dirty(pte);
736 : 0 : set_pte_at(src_mm, addr, src_pte, pte);
737 : : }
738 : : } else if (is_device_private_entry(entry)) {
739 : : page = device_private_entry_to_page(entry);
740 : :
741 : : /*
742 : : * Update rss count even for unaddressable pages, as
743 : : * they should treated just like normal pages in this
744 : : * respect.
745 : : *
746 : : * We will likely want to have some new rss counters
747 : : * for unaddressable pages, at some point. But for now
748 : : * keep things as they are.
749 : : */
750 : : get_page(page);
751 : : rss[mm_counter(page)]++;
752 : : page_dup_rmap(page, false);
753 : :
754 : : /*
755 : : * We do not preserve soft-dirty information, because so
756 : : * far, checkpoint/restore is the only feature that
757 : : * requires that. And checkpoint/restore does not work
758 : : * when a device driver is involved (you cannot easily
759 : : * save and restore device driver state).
760 : : */
761 : : if (is_write_device_private_entry(entry) &&
762 : : is_cow_mapping(vm_flags)) {
763 : : make_device_private_entry_read(&entry);
764 : : pte = swp_entry_to_pte(entry);
765 : : set_pte_at(src_mm, addr, src_pte, pte);
766 : : }
767 : : }
768 : 0 : goto out_set_pte;
769 : : }
770 : :
771 : : /*
772 : : * If it's a COW mapping, write protect it both
773 : : * in the parent and the child
774 : : */
775 [ + + + + ]: 648069 : if (is_cow_mapping(vm_flags) && pte_write(pte)) {
776 : 179459 : ptep_set_wrprotect(src_mm, addr, src_pte);
777 : 179459 : pte = pte_wrprotect(pte);
778 : : }
779 : :
780 : : /*
781 : : * If it's a shared mapping, mark it clean in
782 : : * the child
783 : : */
784 [ + + ]: 648069 : if (vm_flags & VM_SHARED)
785 : 880 : pte = pte_mkclean(pte);
786 : 648069 : pte = pte_mkold(pte);
787 : :
788 : 648069 : page = vm_normal_page(vma, addr, pte);
789 [ + + ]: 648069 : if (page) {
790 [ - + ]: 635859 : get_page(page);
791 : 635859 : page_dup_rmap(page, false);
792 : 635859 : rss[mm_counter(page)]++;
793 : 12210 : } else if (pte_devmap(pte)) {
794 : : page = pte_page(pte);
795 : : }
796 : :
797 : 12210 : out_set_pte:
798 : 648069 : set_pte_at(dst_mm, addr, dst_pte, pte);
799 : 648069 : return 0;
800 : : }
801 : :
802 : 225777 : static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
803 : : pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
804 : : unsigned long addr, unsigned long end)
805 : : {
806 : 225777 : pte_t *orig_src_pte, *orig_dst_pte;
807 : 225777 : pte_t *src_pte, *dst_pte;
808 : 225777 : spinlock_t *src_ptl, *dst_ptl;
809 : 225777 : int progress = 0;
810 : 225777 : int rss[NR_MM_COUNTERS];
811 : 225777 : swp_entry_t entry = (swp_entry_t){0};
812 : :
813 : 225790 : again:
814 : 225790 : init_rss_vec(rss);
815 : :
816 [ + + + - : 451580 : dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
+ - ]
817 [ - + ]: 225790 : if (!dst_pte)
818 : 0 : return -ENOMEM;
819 [ + - ]: 225790 : src_pte = pte_offset_map(src_pmd, addr);
820 [ + - ]: 225790 : src_ptl = pte_lockptr(src_mm, src_pmd);
821 : 225790 : spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
822 : 225790 : orig_src_pte = src_pte;
823 : 225790 : orig_dst_pte = dst_pte;
824 : 1545758 : arch_enter_lazy_mmu_mode();
825 : :
826 : 1545758 : do {
827 : : /*
828 : : * We are holding two locks at this point - either of them
829 : : * could generate latencies in another task on another CPU.
830 : : */
831 [ + + ]: 1545758 : if (progress >= 32) {
832 : 99944 : progress = 0;
833 [ + + ]: 99944 : if (need_resched() ||
834 : : spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
835 : : break;
836 : : }
837 [ + + ]: 1545745 : if (pte_none(*src_pte)) {
838 : 897676 : progress++;
839 : 897676 : continue;
840 : : }
841 : 648069 : entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
842 : : vma, addr, rss);
843 [ + - ]: 648069 : if (entry.val)
844 : : break;
845 : 648069 : progress += 8;
846 [ + + ]: 1545745 : } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
847 : :
848 : 225790 : arch_leave_lazy_mmu_mode();
849 : 225790 : spin_unlock(src_ptl);
850 : 225790 : pte_unmap(orig_src_pte);
851 : 225790 : add_mm_rss_vec(dst_mm, rss);
852 : 225790 : pte_unmap_unlock(orig_dst_pte, dst_ptl);
853 : 225790 : cond_resched();
854 : :
855 [ - + ]: 225790 : if (entry.val) {
856 [ # # ]: 0 : if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
857 : : return -ENOMEM;
858 : : progress = 0;
859 : : }
860 [ + + ]: 225790 : if (addr != end)
861 : 13 : goto again;
862 : : return 0;
863 : : }
864 : :
865 : 224024 : static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
866 : : pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
867 : : unsigned long addr, unsigned long end)
868 : : {
869 : 224024 : pmd_t *src_pmd, *dst_pmd;
870 : 224024 : unsigned long next;
871 : :
872 : 224024 : dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
873 [ + - ]: 224024 : if (!dst_pmd)
874 : : return -ENOMEM;
875 [ + - ]: 224024 : src_pmd = pmd_offset(src_pud, addr);
876 : 226475 : do {
877 [ + + ]: 226475 : next = pmd_addr_end(addr, end);
878 : 226475 : if (is_swap_pmd(*src_pmd) || pmd_trans_huge(*src_pmd)
879 : : || pmd_devmap(*src_pmd)) {
880 : : int err;
881 : : VM_BUG_ON_VMA(next-addr != HPAGE_PMD_SIZE, vma);
882 : : err = copy_huge_pmd(dst_mm, src_mm,
883 : : dst_pmd, src_pmd, addr, vma);
884 : : if (err == -ENOMEM)
885 : : return -ENOMEM;
886 : : if (!err)
887 : : continue;
888 : : /* fall through */
889 : : }
890 [ + + ]: 226475 : if (pmd_none_or_clear_bad(src_pmd))
891 : 698 : continue;
892 [ + - ]: 225777 : if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
893 : : vma, addr, next))
894 : : return -ENOMEM;
895 [ + + ]: 226475 : } while (dst_pmd++, src_pmd++, addr = next, addr != end);
896 : : return 0;
897 : : }
898 : :
899 : 224024 : static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
900 : : p4d_t *dst_p4d, p4d_t *src_p4d, struct vm_area_struct *vma,
901 : : unsigned long addr, unsigned long end)
902 : : {
903 : 224024 : pud_t *src_pud, *dst_pud;
904 : 224024 : unsigned long next;
905 : :
906 : 224024 : dst_pud = pud_alloc(dst_mm, dst_p4d, addr);
907 [ + - ]: 224024 : if (!dst_pud)
908 : : return -ENOMEM;
909 : 224024 : src_pud = pud_offset(src_p4d, addr);
910 : 224024 : do {
911 [ - + ]: 224024 : next = pud_addr_end(addr, end);
912 : 224024 : if (pud_trans_huge(*src_pud) || pud_devmap(*src_pud)) {
913 : : int err;
914 : :
915 : : VM_BUG_ON_VMA(next-addr != HPAGE_PUD_SIZE, vma);
916 : : err = copy_huge_pud(dst_mm, src_mm,
917 : : dst_pud, src_pud, addr, vma);
918 : : if (err == -ENOMEM)
919 : : return -ENOMEM;
920 : : if (!err)
921 : : continue;
922 : : /* fall through */
923 : : }
924 [ - + ]: 224024 : if (pud_none_or_clear_bad(src_pud))
925 : 0 : continue;
926 [ + - ]: 224024 : if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
927 : : vma, addr, next))
928 : : return -ENOMEM;
929 [ - + ]: 224024 : } while (dst_pud++, src_pud++, addr = next, addr != end);
930 : : return 0;
931 : : }
932 : :
933 : 224024 : static inline int copy_p4d_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
934 : : pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
935 : : unsigned long addr, unsigned long end)
936 : : {
937 : 224024 : p4d_t *src_p4d, *dst_p4d;
938 : 224024 : unsigned long next;
939 : :
940 : 224024 : dst_p4d = p4d_alloc(dst_mm, dst_pgd, addr);
941 [ + - ]: 224024 : if (!dst_p4d)
942 : : return -ENOMEM;
943 : 224024 : src_p4d = p4d_offset(src_pgd, addr);
944 : 224024 : do {
945 [ - + ]: 224024 : next = p4d_addr_end(addr, end);
946 [ + - ]: 224024 : if (p4d_none_or_clear_bad(src_p4d))
947 : 0 : continue;
948 [ + - ]: 224024 : if (copy_pud_range(dst_mm, src_mm, dst_p4d, src_p4d,
949 : : vma, addr, next))
950 : : return -ENOMEM;
951 [ - + ]: 224024 : } while (dst_p4d++, src_p4d++, addr = next, addr != end);
952 : : return 0;
953 : : }
954 : :
955 : 528064 : int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
956 : : struct vm_area_struct *vma)
957 : : {
958 : 528064 : pgd_t *src_pgd, *dst_pgd;
959 : 528064 : unsigned long next;
960 : 528064 : unsigned long addr = vma->vm_start;
961 : 528064 : unsigned long end = vma->vm_end;
962 : 528064 : struct mmu_notifier_range range;
963 : 528064 : bool is_cow;
964 : 528064 : int ret;
965 : :
966 : : /*
967 : : * Don't copy ptes where a page fault will fill them correctly.
968 : : * Fork becomes much lighter when there are big shared or private
969 : : * readonly mappings. The tradeoff is that copy_page_range is more
970 : : * efficient than faulting.
971 : : */
972 [ + + ]: 528064 : if (!(vma->vm_flags & (VM_HUGETLB | VM_PFNMAP | VM_MIXEDMAP)) &&
973 [ + + ]: 518978 : !vma->anon_vma)
974 : : return 0;
975 : :
976 [ - + ]: 224024 : if (is_vm_hugetlb_page(vma))
977 : 0 : return copy_hugetlb_page_range(dst_mm, src_mm, vma);
978 : :
979 [ + + ]: 224024 : if (unlikely(vma->vm_flags & VM_PFNMAP)) {
980 : : /*
981 : : * We do not free on error cases below as remove_vma
982 : : * gets called on error from higher level routine
983 : : */
984 : 9031 : ret = track_pfn_copy(vma);
985 [ + - ]: 9031 : if (ret)
986 : : return ret;
987 : : }
988 : :
989 : : /*
990 : : * We need to invalidate the secondary MMU mappings only when
991 : : * there could be a permission downgrade on the ptes of the
992 : : * parent mm. And a permission downgrade will only happen if
993 : : * is_cow_mapping() returns true.
994 : : */
995 [ + + ]: 224024 : is_cow = is_cow_mapping(vma->vm_flags);
996 : :
997 [ + + ]: 224024 : if (is_cow) {
998 : 214938 : mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_PAGE,
999 : : 0, vma, src_mm, addr, end);
1000 : 214938 : mmu_notifier_invalidate_range_start(&range);
1001 : : }
1002 : :
1003 : 224024 : ret = 0;
1004 : 224024 : dst_pgd = pgd_offset(dst_mm, addr);
1005 : 224024 : src_pgd = pgd_offset(src_mm, addr);
1006 : 224024 : do {
1007 [ + - ]: 224024 : next = pgd_addr_end(addr, end);
1008 [ - + ]: 224024 : if (pgd_none_or_clear_bad(src_pgd))
1009 : 0 : continue;
1010 [ + - ]: 224024 : if (unlikely(copy_p4d_range(dst_mm, src_mm, dst_pgd, src_pgd,
1011 : : vma, addr, next))) {
1012 : : ret = -ENOMEM;
1013 : : break;
1014 : : }
1015 [ - + ]: 224024 : } while (dst_pgd++, src_pgd++, addr = next, addr != end);
1016 : :
1017 [ + + ]: 224024 : if (is_cow)
1018 : 214938 : mmu_notifier_invalidate_range_end(&range);
1019 : : return ret;
1020 : : }
1021 : :
1022 : 1054261 : static unsigned long zap_pte_range(struct mmu_gather *tlb,
1023 : : struct vm_area_struct *vma, pmd_t *pmd,
1024 : : unsigned long addr, unsigned long end,
1025 : : struct zap_details *details)
1026 : : {
1027 : 1054261 : struct mm_struct *mm = tlb->mm;
1028 : 1054261 : int force_flush = 0;
1029 : 1054261 : int rss[NR_MM_COUNTERS];
1030 : 1054261 : spinlock_t *ptl;
1031 : 1054261 : pte_t *start_pte;
1032 : 1054261 : pte_t *pte;
1033 : 1054261 : swp_entry_t entry;
1034 : :
1035 : 1054261 : tlb_change_page_size(tlb, PAGE_SIZE);
1036 : 1054779 : again:
1037 : 1054779 : init_rss_vec(rss);
1038 [ + - ]: 2109558 : start_pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
1039 : 1054779 : pte = start_pte;
1040 : 1054779 : flush_tlb_batched_pending(mm);
1041 : 30263820 : arch_enter_lazy_mmu_mode();
1042 : 30263820 : do {
1043 : 30263820 : pte_t ptent = *pte;
1044 [ + + ]: 30263820 : if (pte_none(ptent))
1045 : 23624150 : continue;
1046 : :
1047 [ + + ]: 6639666 : if (need_resched())
1048 : : break;
1049 : :
1050 [ + - ]: 6639148 : if (pte_present(ptent)) {
1051 : 6639148 : struct page *page;
1052 : :
1053 : 6639148 : page = vm_normal_page(vma, addr, ptent);
1054 [ - + - - ]: 6639148 : if (unlikely(details) && page) {
1055 : : /*
1056 : : * unmap_shared_mapping_pages() wants to
1057 : : * invalidate cache without truncating:
1058 : : * unmap shared but keep private pages.
1059 : : */
1060 [ # # # # ]: 0 : if (details->check_mapping &&
1061 : 0 : details->check_mapping != page_rmapping(page))
1062 : 0 : continue;
1063 : : }
1064 : 6639148 : ptent = ptep_get_and_clear_full(mm, addr, pte,
1065 [ + + ]: 6639148 : tlb->fullmm);
1066 [ + + ]: 6639148 : tlb_remove_tlb_entry(tlb, pte, addr);
1067 [ + + ]: 6639148 : if (unlikely(!page))
1068 : 12743 : continue;
1069 : :
1070 [ - + + + ]: 6626405 : if (!PageAnon(page)) {
1071 [ - + ]: 5708098 : if (pte_dirty(ptent)) {
1072 : 0 : force_flush = 1;
1073 : 0 : set_page_dirty(page);
1074 : : }
1075 [ + + ]: 5708098 : if (pte_young(ptent) &&
1076 [ + - ]: 5703397 : likely(!(vma->vm_flags & VM_SEQ_READ)))
1077 : 5703397 : mark_page_accessed(page);
1078 : : }
1079 : 6626405 : rss[mm_counter(page)]--;
1080 : 6626405 : page_remove_rmap(page, false);
1081 [ - + ]: 6626405 : if (unlikely(page_mapcount(page) < 0))
1082 : 0 : print_bad_pte(vma, addr, ptent, page);
1083 [ + - ]: 6626405 : if (unlikely(__tlb_remove_page(tlb, page))) {
1084 : : force_flush = 1;
1085 : : addr += PAGE_SIZE;
1086 : : break;
1087 : : }
1088 : 6626405 : continue;
1089 : : }
1090 : :
1091 [ # # ]: 0 : entry = pte_to_swp_entry(ptent);
1092 [ # # ]: 0 : if (non_swap_entry(entry) && is_device_private_entry(entry)) {
1093 : : struct page *page = device_private_entry_to_page(entry);
1094 : :
1095 : : if (unlikely(details && details->check_mapping)) {
1096 : : /*
1097 : : * unmap_shared_mapping_pages() wants to
1098 : : * invalidate cache without truncating:
1099 : : * unmap shared but keep private pages.
1100 : : */
1101 : : if (details->check_mapping !=
1102 : : page_rmapping(page))
1103 : : continue;
1104 : : }
1105 : :
1106 : : pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
1107 : : rss[mm_counter(page)]--;
1108 : : page_remove_rmap(page, false);
1109 : : put_page(page);
1110 : : continue;
1111 : : }
1112 : :
1113 : : /* If details->check_mapping, we leave swap entries. */
1114 [ # # ]: 0 : if (unlikely(details))
1115 : 0 : continue;
1116 : :
1117 [ # # ]: 0 : if (!non_swap_entry(entry))
1118 : 0 : rss[MM_SWAPENTS]--;
1119 [ # # ]: 0 : else if (is_migration_entry(entry)) {
1120 : 0 : struct page *page;
1121 : :
1122 : 0 : page = migration_entry_to_page(entry);
1123 : 0 : rss[mm_counter(page)]--;
1124 : : }
1125 [ # # ]: 0 : if (unlikely(!free_swap_and_cache(entry)))
1126 : 0 : print_bad_pte(vma, addr, ptent, NULL);
1127 : 0 : pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
1128 [ + + ]: 30263300 : } while (pte++, addr += PAGE_SIZE, addr != end);
1129 : :
1130 : 1054779 : add_mm_rss_vec(mm, rss);
1131 : 1054779 : arch_leave_lazy_mmu_mode();
1132 : :
1133 : : /* Do the actual TLB flush before dropping ptl */
1134 [ - + ]: 1054779 : if (force_flush)
1135 : 0 : tlb_flush_mmu_tlbonly(tlb);
1136 : 1054779 : pte_unmap_unlock(start_pte, ptl);
1137 : :
1138 : : /*
1139 : : * If we forced a TLB flush (either due to running out of
1140 : : * batch buffers or because we needed to flush dirty TLB
1141 : : * entries before releasing the ptl), free the batched
1142 : : * memory too. Restart if we didn't do everything.
1143 : : */
1144 [ - + ]: 1054779 : if (force_flush) {
1145 : 0 : force_flush = 0;
1146 : 0 : tlb_flush_mmu(tlb);
1147 : : }
1148 : :
1149 [ + + ]: 1054779 : if (addr != end) {
1150 : 518 : cond_resched();
1151 : 518 : goto again;
1152 : : }
1153 : :
1154 : 1054261 : return addr;
1155 : : }
1156 : :
1157 : 1011598 : static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
1158 : : struct vm_area_struct *vma, pud_t *pud,
1159 : : unsigned long addr, unsigned long end,
1160 : : struct zap_details *details)
1161 : : {
1162 : 1011598 : pmd_t *pmd;
1163 : 1011598 : unsigned long next;
1164 : :
1165 [ + - ]: 1011598 : pmd = pmd_offset(pud, addr);
1166 : 1074344 : do {
1167 [ + + ]: 1074344 : next = pmd_addr_end(addr, end);
1168 : 1074344 : if (is_swap_pmd(*pmd) || pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
1169 : : if (next - addr != HPAGE_PMD_SIZE)
1170 : : __split_huge_pmd(vma, pmd, addr, false, NULL);
1171 : : else if (zap_huge_pmd(tlb, vma, pmd, addr))
1172 : : goto next;
1173 : : /* fall through */
1174 : : }
1175 : : /*
1176 : : * Here there can be other concurrent MADV_DONTNEED or
1177 : : * trans huge page faults running, and if the pmd is
1178 : : * none or trans huge it can change under us. This is
1179 : : * because MADV_DONTNEED holds the mmap_sem in read
1180 : : * mode.
1181 : : */
1182 [ + + ]: 1074344 : if (pmd_none_or_trans_huge_or_clear_bad(pmd))
1183 : 20083 : goto next;
1184 : 1054261 : next = zap_pte_range(tlb, vma, pmd, addr, next, details);
1185 : 1074344 : next:
1186 : 1074344 : cond_resched();
1187 [ + + ]: 1074344 : } while (pmd++, addr = next, addr != end);
1188 : :
1189 : 1011598 : return addr;
1190 : : }
1191 : :
1192 : 1015867 : static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
1193 : : struct vm_area_struct *vma, p4d_t *p4d,
1194 : : unsigned long addr, unsigned long end,
1195 : : struct zap_details *details)
1196 : : {
1197 : 1015867 : pud_t *pud;
1198 : 1015867 : unsigned long next;
1199 : :
1200 : 1015867 : pud = pud_offset(p4d, addr);
1201 : 1015917 : do {
1202 [ + + ]: 1015917 : next = pud_addr_end(addr, end);
1203 : 1015917 : if (pud_trans_huge(*pud) || pud_devmap(*pud)) {
1204 : : if (next - addr != HPAGE_PUD_SIZE) {
1205 : : VM_BUG_ON_VMA(!rwsem_is_locked(&tlb->mm->mmap_sem), vma);
1206 : : split_huge_pud(vma, pud, addr);
1207 : : } else if (zap_huge_pud(tlb, vma, pud, addr))
1208 : : goto next;
1209 : : /* fall through */
1210 : : }
1211 [ + + ]: 1015917 : if (pud_none_or_clear_bad(pud))
1212 : 4319 : continue;
1213 : 1011598 : next = zap_pmd_range(tlb, vma, pud, addr, next, details);
1214 : : next:
1215 : 1011598 : cond_resched();
1216 [ + + ]: 1015917 : } while (pud++, addr = next, addr != end);
1217 : :
1218 : 1015867 : return addr;
1219 : : }
1220 : :
1221 : 1029477 : static inline unsigned long zap_p4d_range(struct mmu_gather *tlb,
1222 : : struct vm_area_struct *vma, pgd_t *pgd,
1223 : : unsigned long addr, unsigned long end,
1224 : : struct zap_details *details)
1225 : : {
1226 : 1029477 : p4d_t *p4d;
1227 : 1029477 : unsigned long next;
1228 : :
1229 : 1029477 : p4d = p4d_offset(pgd, addr);
1230 : 1029477 : do {
1231 [ - + ]: 1029477 : next = p4d_addr_end(addr, end);
1232 [ + + ]: 1029477 : if (p4d_none_or_clear_bad(p4d))
1233 : 13610 : continue;
1234 : 1015867 : next = zap_pud_range(tlb, vma, p4d, addr, next, details);
1235 [ - + ]: 1029477 : } while (p4d++, addr = next, addr != end);
1236 : :
1237 : 1029477 : return addr;
1238 : : }
1239 : :
1240 : 1029477 : void unmap_page_range(struct mmu_gather *tlb,
1241 : : struct vm_area_struct *vma,
1242 : : unsigned long addr, unsigned long end,
1243 : : struct zap_details *details)
1244 : : {
1245 : 1029477 : pgd_t *pgd;
1246 : 1029477 : unsigned long next;
1247 : :
1248 [ - + ]: 1029477 : BUG_ON(addr >= end);
1249 : 1029477 : tlb_start_vma(tlb, vma);
1250 : 1029477 : pgd = pgd_offset(vma->vm_mm, addr);
1251 : 1029477 : do {
1252 [ + - ]: 1029477 : next = pgd_addr_end(addr, end);
1253 [ - + ]: 1029477 : if (pgd_none_or_clear_bad(pgd))
1254 : 0 : continue;
1255 : 1029477 : next = zap_p4d_range(tlb, vma, pgd, addr, next, details);
1256 [ - + ]: 1029477 : } while (pgd++, addr = next, addr != end);
1257 : 1029477 : tlb_end_vma(tlb, vma);
1258 : 1029477 : }
1259 : :
1260 : :
1261 : 1029477 : static void unmap_single_vma(struct mmu_gather *tlb,
1262 : : struct vm_area_struct *vma, unsigned long start_addr,
1263 : : unsigned long end_addr,
1264 : : struct zap_details *details)
1265 : : {
1266 : 1029477 : unsigned long start = max(vma->vm_start, start_addr);
1267 : 1029477 : unsigned long end;
1268 : :
1269 [ + - ]: 1029477 : if (start >= vma->vm_end)
1270 : : return;
1271 : 1029477 : end = min(vma->vm_end, end_addr);
1272 [ + - ]: 1029477 : if (end <= vma->vm_start)
1273 : : return;
1274 : :
1275 [ + + ]: 1029477 : if (vma->vm_file)
1276 : 868351 : uprobe_munmap(vma, start, end);
1277 : :
1278 [ + + ]: 1029477 : if (unlikely(vma->vm_flags & VM_PFNMAP))
1279 : 17732 : untrack_pfn(vma, 0, 0);
1280 : :
1281 [ + - ]: 1029477 : if (start != end) {
1282 [ - + ]: 1029477 : if (unlikely(is_vm_hugetlb_page(vma))) {
1283 : : /*
1284 : : * It is undesirable to test vma->vm_file as it
1285 : : * should be non-null for valid hugetlb area.
1286 : : * However, vm_file will be NULL in the error
1287 : : * cleanup path of mmap_region. When
1288 : : * hugetlbfs ->mmap method fails,
1289 : : * mmap_region() nullifies vma->vm_file
1290 : : * before calling this function to clean up.
1291 : : * Since no pte has actually been setup, it is
1292 : : * safe to do nothing in this case.
1293 : : */
1294 [ # # ]: 0 : if (vma->vm_file) {
1295 : 0 : i_mmap_lock_write(vma->vm_file->f_mapping);
1296 : 0 : __unmap_hugepage_range_final(tlb, vma, start, end, NULL);
1297 : 0 : i_mmap_unlock_write(vma->vm_file->f_mapping);
1298 : : }
1299 : : } else
1300 : 1029477 : unmap_page_range(tlb, vma, start, end, details);
1301 : : }
1302 : : }
1303 : :
1304 : : /**
1305 : : * unmap_vmas - unmap a range of memory covered by a list of vma's
1306 : : * @tlb: address of the caller's struct mmu_gather
1307 : : * @vma: the starting vma
1308 : : * @start_addr: virtual address at which to start unmapping
1309 : : * @end_addr: virtual address at which to end unmapping
1310 : : *
1311 : : * Unmap all pages in the vma list.
1312 : : *
1313 : : * Only addresses between `start' and `end' will be unmapped.
1314 : : *
1315 : : * The VMA list must be sorted in ascending virtual address order.
1316 : : *
1317 : : * unmap_vmas() assumes that the caller will flush the whole unmapped address
1318 : : * range after unmap_vmas() returns. So the only responsibility here is to
1319 : : * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1320 : : * drops the lock and schedules.
1321 : : */
1322 : 150505 : void unmap_vmas(struct mmu_gather *tlb,
1323 : : struct vm_area_struct *vma, unsigned long start_addr,
1324 : : unsigned long end_addr)
1325 : : {
1326 : 150505 : struct mmu_notifier_range range;
1327 : :
1328 : 150505 : mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, vma->vm_mm,
1329 : : start_addr, end_addr);
1330 : 150505 : mmu_notifier_invalidate_range_start(&range);
1331 [ + + + - ]: 1330487 : for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next)
1332 : 1029477 : unmap_single_vma(tlb, vma, start_addr, end_addr, NULL);
1333 : 150505 : mmu_notifier_invalidate_range_end(&range);
1334 : 150505 : }
1335 : :
1336 : : /**
1337 : : * zap_page_range - remove user pages in a given range
1338 : : * @vma: vm_area_struct holding the applicable pages
1339 : : * @start: starting address of pages to zap
1340 : : * @size: number of bytes to zap
1341 : : *
1342 : : * Caller must protect the VMA list
1343 : : */
1344 : 0 : void zap_page_range(struct vm_area_struct *vma, unsigned long start,
1345 : : unsigned long size)
1346 : : {
1347 : 0 : struct mmu_notifier_range range;
1348 : 0 : struct mmu_gather tlb;
1349 : :
1350 : 0 : lru_add_drain();
1351 : 0 : mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
1352 : : start, start + size);
1353 : 0 : tlb_gather_mmu(&tlb, vma->vm_mm, start, range.end);
1354 : 0 : update_hiwater_rss(vma->vm_mm);
1355 : 0 : mmu_notifier_invalidate_range_start(&range);
1356 [ # # # # ]: 0 : for ( ; vma && vma->vm_start < range.end; vma = vma->vm_next)
1357 : 0 : unmap_single_vma(&tlb, vma, start, range.end, NULL);
1358 : 0 : mmu_notifier_invalidate_range_end(&range);
1359 : 0 : tlb_finish_mmu(&tlb, start, range.end);
1360 : 0 : }
1361 : :
1362 : : /**
1363 : : * zap_page_range_single - remove user pages in a given range
1364 : : * @vma: vm_area_struct holding the applicable pages
1365 : : * @address: starting address of pages to zap
1366 : : * @size: number of bytes to zap
1367 : : * @details: details of shared cache invalidation
1368 : : *
1369 : : * The range must fit into one VMA.
1370 : : */
1371 : 0 : static void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
1372 : : unsigned long size, struct zap_details *details)
1373 : : {
1374 : 0 : struct mmu_notifier_range range;
1375 : 0 : struct mmu_gather tlb;
1376 : :
1377 : 0 : lru_add_drain();
1378 : 0 : mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
1379 : : address, address + size);
1380 : 0 : tlb_gather_mmu(&tlb, vma->vm_mm, address, range.end);
1381 : 0 : update_hiwater_rss(vma->vm_mm);
1382 : 0 : mmu_notifier_invalidate_range_start(&range);
1383 : 0 : unmap_single_vma(&tlb, vma, address, range.end, details);
1384 : 0 : mmu_notifier_invalidate_range_end(&range);
1385 : 0 : tlb_finish_mmu(&tlb, address, range.end);
1386 : 0 : }
1387 : :
1388 : : /**
1389 : : * zap_vma_ptes - remove ptes mapping the vma
1390 : : * @vma: vm_area_struct holding ptes to be zapped
1391 : : * @address: starting address of pages to zap
1392 : : * @size: number of bytes to zap
1393 : : *
1394 : : * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1395 : : *
1396 : : * The entire address range must be fully contained within the vma.
1397 : : *
1398 : : */
1399 : 0 : void zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1400 : : unsigned long size)
1401 : : {
1402 [ # # # # ]: 0 : if (address < vma->vm_start || address + size > vma->vm_end ||
1403 [ # # ]: 0 : !(vma->vm_flags & VM_PFNMAP))
1404 : : return;
1405 : :
1406 : 0 : zap_page_range_single(vma, address, size, NULL);
1407 : : }
1408 : : EXPORT_SYMBOL_GPL(zap_vma_ptes);
1409 : :
1410 : 110456 : pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
1411 : : spinlock_t **ptl)
1412 : : {
1413 : 110456 : pgd_t *pgd;
1414 : 110456 : p4d_t *p4d;
1415 : 110456 : pud_t *pud;
1416 : 110456 : pmd_t *pmd;
1417 : :
1418 : 110456 : pgd = pgd_offset(mm, addr);
1419 : 110456 : p4d = p4d_alloc(mm, pgd, addr);
1420 [ + - ]: 110456 : if (!p4d)
1421 : : return NULL;
1422 : 110456 : pud = pud_alloc(mm, p4d, addr);
1423 [ + - ]: 110456 : if (!pud)
1424 : : return NULL;
1425 : 110456 : pmd = pmd_alloc(mm, pud, addr);
1426 [ + - ]: 110456 : if (!pmd)
1427 : : return NULL;
1428 : :
1429 : 110456 : VM_BUG_ON(pmd_trans_huge(*pmd));
1430 [ + + + - : 220912 : return pte_alloc_map_lock(mm, pmd, addr, ptl);
+ - ]
1431 : : }
1432 : :
1433 : : /*
1434 : : * This is the old fallback for page remapping.
1435 : : *
1436 : : * For historical reasons, it only allows reserved pages. Only
1437 : : * old drivers should use this, and they needed to mark their
1438 : : * pages reserved for the old functions anyway.
1439 : : */
1440 : : static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1441 : : struct page *page, pgprot_t prot)
1442 : : {
1443 : : struct mm_struct *mm = vma->vm_mm;
1444 : : int retval;
1445 : : pte_t *pte;
1446 : : spinlock_t *ptl;
1447 : :
1448 : : retval = -EINVAL;
1449 : : if (PageAnon(page) || PageSlab(page) || page_has_type(page))
1450 : : goto out;
1451 : : retval = -ENOMEM;
1452 : : flush_dcache_page(page);
1453 : : pte = get_locked_pte(mm, addr, &ptl);
1454 : : if (!pte)
1455 : : goto out;
1456 : : retval = -EBUSY;
1457 : : if (!pte_none(*pte))
1458 : : goto out_unlock;
1459 : :
1460 : : /* Ok, finally just insert the thing.. */
1461 : : get_page(page);
1462 : : inc_mm_counter_fast(mm, mm_counter_file(page));
1463 : : page_add_file_rmap(page, false);
1464 : : set_pte_at(mm, addr, pte, mk_pte(page, prot));
1465 : :
1466 : : retval = 0;
1467 : : out_unlock:
1468 : : pte_unmap_unlock(pte, ptl);
1469 : : out:
1470 : : return retval;
1471 : : }
1472 : :
1473 : : /**
1474 : : * vm_insert_page - insert single page into user vma
1475 : : * @vma: user vma to map to
1476 : : * @addr: target user address of this page
1477 : : * @page: source kernel page
1478 : : *
1479 : : * This allows drivers to insert individual pages they've allocated
1480 : : * into a user vma.
1481 : : *
1482 : : * The page has to be a nice clean _individual_ kernel allocation.
1483 : : * If you allocate a compound page, you need to have marked it as
1484 : : * such (__GFP_COMP), or manually just split the page up yourself
1485 : : * (see split_page()).
1486 : : *
1487 : : * NOTE! Traditionally this was done with "remap_pfn_range()" which
1488 : : * took an arbitrary page protection parameter. This doesn't allow
1489 : : * that. Your vma protection will have to be set up correctly, which
1490 : : * means that if you want a shared writable mapping, you'd better
1491 : : * ask for a shared writable mapping!
1492 : : *
1493 : : * The page does not need to be reserved.
1494 : : *
1495 : : * Usually this function is called from f_op->mmap() handler
1496 : : * under mm->mmap_sem write-lock, so it can change vma->vm_flags.
1497 : : * Caller must set VM_MIXEDMAP on vma if it wants to call this
1498 : : * function from other places, for example from page-fault handler.
1499 : : *
1500 : : * Return: %0 on success, negative error code otherwise.
1501 : : */
1502 : 176 : int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1503 : : struct page *page)
1504 : : {
1505 [ + - + - ]: 176 : if (addr < vma->vm_start || addr >= vma->vm_end)
1506 : : return -EFAULT;
1507 [ - + + - ]: 352 : if (!page_count(page))
1508 : : return -EINVAL;
1509 [ + + ]: 176 : if (!(vma->vm_flags & VM_MIXEDMAP)) {
1510 [ - + ]: 11 : BUG_ON(down_read_trylock(&vma->vm_mm->mmap_sem));
1511 [ - + ]: 11 : BUG_ON(vma->vm_flags & VM_PFNMAP);
1512 : 11 : vma->vm_flags |= VM_MIXEDMAP;
1513 : : }
1514 : 176 : return insert_page(vma, addr, page, vma->vm_page_prot);
1515 : : }
1516 : : EXPORT_SYMBOL(vm_insert_page);
1517 : :
1518 : : /*
1519 : : * __vm_map_pages - maps range of kernel pages into user vma
1520 : : * @vma: user vma to map to
1521 : : * @pages: pointer to array of source kernel pages
1522 : : * @num: number of pages in page array
1523 : : * @offset: user's requested vm_pgoff
1524 : : *
1525 : : * This allows drivers to map range of kernel pages into a user vma.
1526 : : *
1527 : : * Return: 0 on success and error code otherwise.
1528 : : */
1529 : 0 : static int __vm_map_pages(struct vm_area_struct *vma, struct page **pages,
1530 : : unsigned long num, unsigned long offset)
1531 : : {
1532 [ # # ]: 0 : unsigned long count = vma_pages(vma);
1533 : 0 : unsigned long uaddr = vma->vm_start;
1534 : 0 : int ret, i;
1535 : :
1536 : : /* Fail if the user requested offset is beyond the end of the object */
1537 [ # # ]: 0 : if (offset >= num)
1538 : : return -ENXIO;
1539 : :
1540 : : /* Fail if the user requested size exceeds available object size */
1541 [ # # ]: 0 : if (count > num - offset)
1542 : : return -ENXIO;
1543 : :
1544 [ # # ]: 0 : for (i = 0; i < count; i++) {
1545 : 0 : ret = vm_insert_page(vma, uaddr, pages[offset + i]);
1546 [ # # ]: 0 : if (ret < 0)
1547 : 0 : return ret;
1548 : 0 : uaddr += PAGE_SIZE;
1549 : : }
1550 : :
1551 : : return 0;
1552 : : }
1553 : :
1554 : : /**
1555 : : * vm_map_pages - maps range of kernel pages starts with non zero offset
1556 : : * @vma: user vma to map to
1557 : : * @pages: pointer to array of source kernel pages
1558 : : * @num: number of pages in page array
1559 : : *
1560 : : * Maps an object consisting of @num pages, catering for the user's
1561 : : * requested vm_pgoff
1562 : : *
1563 : : * If we fail to insert any page into the vma, the function will return
1564 : : * immediately leaving any previously inserted pages present. Callers
1565 : : * from the mmap handler may immediately return the error as their caller
1566 : : * will destroy the vma, removing any successfully inserted pages. Other
1567 : : * callers should make their own arrangements for calling unmap_region().
1568 : : *
1569 : : * Context: Process context. Called by mmap handlers.
1570 : : * Return: 0 on success and error code otherwise.
1571 : : */
1572 : 0 : int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
1573 : : unsigned long num)
1574 : : {
1575 : 0 : return __vm_map_pages(vma, pages, num, vma->vm_pgoff);
1576 : : }
1577 : : EXPORT_SYMBOL(vm_map_pages);
1578 : :
1579 : : /**
1580 : : * vm_map_pages_zero - map range of kernel pages starts with zero offset
1581 : : * @vma: user vma to map to
1582 : : * @pages: pointer to array of source kernel pages
1583 : : * @num: number of pages in page array
1584 : : *
1585 : : * Similar to vm_map_pages(), except that it explicitly sets the offset
1586 : : * to 0. This function is intended for the drivers that did not consider
1587 : : * vm_pgoff.
1588 : : *
1589 : : * Context: Process context. Called by mmap handlers.
1590 : : * Return: 0 on success and error code otherwise.
1591 : : */
1592 : 0 : int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
1593 : : unsigned long num)
1594 : : {
1595 : 0 : return __vm_map_pages(vma, pages, num, 0);
1596 : : }
1597 : : EXPORT_SYMBOL(vm_map_pages_zero);
1598 : :
1599 : 775 : static vm_fault_t insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1600 : : pfn_t pfn, pgprot_t prot, bool mkwrite)
1601 : : {
1602 : 775 : struct mm_struct *mm = vma->vm_mm;
1603 : 775 : pte_t *pte, entry;
1604 : 775 : spinlock_t *ptl;
1605 : :
1606 : 775 : pte = get_locked_pte(mm, addr, &ptl);
1607 [ + - ]: 775 : if (!pte)
1608 : : return VM_FAULT_OOM;
1609 [ - + ]: 775 : if (!pte_none(*pte)) {
1610 [ # # ]: 0 : if (mkwrite) {
1611 : : /*
1612 : : * For read faults on private mappings the PFN passed
1613 : : * in may not match the PFN we have mapped if the
1614 : : * mapped PFN is a writeable COW page. In the mkwrite
1615 : : * case we are creating a writable PTE for a shared
1616 : : * mapping and we expect the PFNs to match. If they
1617 : : * don't match, we are likely racing with block
1618 : : * allocation and mapping invalidation so just skip the
1619 : : * update.
1620 : : */
1621 [ # # # # ]: 0 : if (pte_pfn(*pte) != pfn_t_to_pfn(pfn)) {
1622 [ # # # # ]: 0 : WARN_ON_ONCE(!is_zero_pfn(pte_pfn(*pte)));
1623 : 0 : goto out_unlock;
1624 : : }
1625 [ # # ]: 0 : entry = pte_mkyoung(*pte);
1626 [ # # ]: 0 : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1627 : 0 : if (ptep_set_access_flags(vma, addr, pte, entry, 1))
1628 : : update_mmu_cache(vma, addr, pte);
1629 : : }
1630 : 0 : goto out_unlock;
1631 : : }
1632 : :
1633 : : /* Ok, finally just insert the thing.. */
1634 [ - + ]: 775 : if (pfn_t_devmap(pfn))
1635 [ # # ]: 0 : entry = pte_mkdevmap(pfn_t_pte(pfn, prot));
1636 : : else
1637 [ + - ]: 775 : entry = pte_mkspecial(pfn_t_pte(pfn, prot));
1638 : :
1639 [ - + ]: 775 : if (mkwrite) {
1640 [ # # ]: 0 : entry = pte_mkyoung(entry);
1641 [ # # ]: 0 : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1642 : : }
1643 : :
1644 : 775 : set_pte_at(mm, addr, pte, entry);
1645 : 775 : update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
1646 : :
1647 : 775 : out_unlock:
1648 : 775 : pte_unmap_unlock(pte, ptl);
1649 : 775 : return VM_FAULT_NOPAGE;
1650 : : }
1651 : :
1652 : : /**
1653 : : * vmf_insert_pfn_prot - insert single pfn into user vma with specified pgprot
1654 : : * @vma: user vma to map to
1655 : : * @addr: target user address of this page
1656 : : * @pfn: source kernel pfn
1657 : : * @pgprot: pgprot flags for the inserted page
1658 : : *
1659 : : * This is exactly like vmf_insert_pfn(), except that it allows drivers to
1660 : : * to override pgprot on a per-page basis.
1661 : : *
1662 : : * This only makes sense for IO mappings, and it makes no sense for
1663 : : * COW mappings. In general, using multiple vmas is preferable;
1664 : : * vmf_insert_pfn_prot should only be used if using multiple VMAs is
1665 : : * impractical.
1666 : : *
1667 : : * See vmf_insert_mixed_prot() for a discussion of the implication of using
1668 : : * a value of @pgprot different from that of @vma->vm_page_prot.
1669 : : *
1670 : : * Context: Process context. May allocate using %GFP_KERNEL.
1671 : : * Return: vm_fault_t value.
1672 : : */
1673 : 775 : vm_fault_t vmf_insert_pfn_prot(struct vm_area_struct *vma, unsigned long addr,
1674 : : unsigned long pfn, pgprot_t pgprot)
1675 : : {
1676 : : /*
1677 : : * Technically, architectures with pte_special can avoid all these
1678 : : * restrictions (same for remap_pfn_range). However we would like
1679 : : * consistency in testing and feature parity among all, so we should
1680 : : * try to keep these invariants in place for everybody.
1681 : : */
1682 [ - + ]: 775 : BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1683 [ - + ]: 775 : BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1684 : : (VM_PFNMAP|VM_MIXEDMAP));
1685 [ + - - + ]: 775 : BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1686 [ - + - - ]: 775 : BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
1687 : :
1688 [ + - + - ]: 775 : if (addr < vma->vm_start || addr >= vma->vm_end)
1689 : : return VM_FAULT_SIGBUS;
1690 : :
1691 [ + - ]: 775 : if (!pfn_modify_allowed(pfn, pgprot))
1692 : : return VM_FAULT_SIGBUS;
1693 : :
1694 : 775 : track_pfn_insert(vma, &pgprot, __pfn_to_pfn_t(pfn, PFN_DEV));
1695 : :
1696 : 775 : return insert_pfn(vma, addr, __pfn_to_pfn_t(pfn, PFN_DEV), pgprot,
1697 : : false);
1698 : : }
1699 : : EXPORT_SYMBOL(vmf_insert_pfn_prot);
1700 : :
1701 : : /**
1702 : : * vmf_insert_pfn - insert single pfn into user vma
1703 : : * @vma: user vma to map to
1704 : : * @addr: target user address of this page
1705 : : * @pfn: source kernel pfn
1706 : : *
1707 : : * Similar to vm_insert_page, this allows drivers to insert individual pages
1708 : : * they've allocated into a user vma. Same comments apply.
1709 : : *
1710 : : * This function should only be called from a vm_ops->fault handler, and
1711 : : * in that case the handler should return the result of this function.
1712 : : *
1713 : : * vma cannot be a COW mapping.
1714 : : *
1715 : : * As this is called only for pages that do not currently exist, we
1716 : : * do not need to flush old virtual caches or the TLB.
1717 : : *
1718 : : * Context: Process context. May allocate using %GFP_KERNEL.
1719 : : * Return: vm_fault_t value.
1720 : : */
1721 : 437 : vm_fault_t vmf_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1722 : : unsigned long pfn)
1723 : : {
1724 : 437 : return vmf_insert_pfn_prot(vma, addr, pfn, vma->vm_page_prot);
1725 : : }
1726 : : EXPORT_SYMBOL(vmf_insert_pfn);
1727 : :
1728 : 0 : static bool vm_mixed_ok(struct vm_area_struct *vma, pfn_t pfn)
1729 : : {
1730 : : /* these checks mirror the abort conditions in vm_normal_page */
1731 : 0 : if (vma->vm_flags & VM_MIXEDMAP)
1732 : : return true;
1733 [ # # ]: 0 : if (pfn_t_devmap(pfn))
1734 : : return true;
1735 [ # # ]: 0 : if (pfn_t_special(pfn))
1736 : : return true;
1737 [ # # ]: 0 : if (is_zero_pfn(pfn_t_to_pfn(pfn)))
1738 : 0 : return true;
1739 : : return false;
1740 : : }
1741 : :
1742 : 0 : static vm_fault_t __vm_insert_mixed(struct vm_area_struct *vma,
1743 : : unsigned long addr, pfn_t pfn, pgprot_t pgprot,
1744 : : bool mkwrite)
1745 : : {
1746 : 0 : int err;
1747 : :
1748 [ # # # # ]: 0 : BUG_ON(!vm_mixed_ok(vma, pfn));
1749 : :
1750 [ # # # # ]: 0 : if (addr < vma->vm_start || addr >= vma->vm_end)
1751 : : return VM_FAULT_SIGBUS;
1752 : :
1753 : 0 : track_pfn_insert(vma, &pgprot, pfn);
1754 : :
1755 [ # # ]: 0 : if (!pfn_modify_allowed(pfn_t_to_pfn(pfn), pgprot))
1756 : : return VM_FAULT_SIGBUS;
1757 : :
1758 : : /*
1759 : : * If we don't have pte special, then we have to use the pfn_valid()
1760 : : * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1761 : : * refcount the page if pfn_valid is true (hence insert_page rather
1762 : : * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1763 : : * without pte special, it would there be refcounted as a normal page.
1764 : : */
1765 : 0 : if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL) &&
1766 : : !pfn_t_devmap(pfn) && pfn_t_valid(pfn)) {
1767 : : struct page *page;
1768 : :
1769 : : /*
1770 : : * At this point we are committed to insert_page()
1771 : : * regardless of whether the caller specified flags that
1772 : : * result in pfn_t_has_page() == false.
1773 : : */
1774 : : page = pfn_to_page(pfn_t_to_pfn(pfn));
1775 : : err = insert_page(vma, addr, page, pgprot);
1776 : : } else {
1777 : 0 : return insert_pfn(vma, addr, pfn, pgprot, mkwrite);
1778 : : }
1779 : :
1780 : : if (err == -ENOMEM)
1781 : : return VM_FAULT_OOM;
1782 : : if (err < 0 && err != -EBUSY)
1783 : : return VM_FAULT_SIGBUS;
1784 : :
1785 : : return VM_FAULT_NOPAGE;
1786 : : }
1787 : :
1788 : : /**
1789 : : * vmf_insert_mixed_prot - insert single pfn into user vma with specified pgprot
1790 : : * @vma: user vma to map to
1791 : : * @addr: target user address of this page
1792 : : * @pfn: source kernel pfn
1793 : : * @pgprot: pgprot flags for the inserted page
1794 : : *
1795 : : * This is exactly like vmf_insert_mixed(), except that it allows drivers to
1796 : : * to override pgprot on a per-page basis.
1797 : : *
1798 : : * Typically this function should be used by drivers to set caching- and
1799 : : * encryption bits different than those of @vma->vm_page_prot, because
1800 : : * the caching- or encryption mode may not be known at mmap() time.
1801 : : * This is ok as long as @vma->vm_page_prot is not used by the core vm
1802 : : * to set caching and encryption bits for those vmas (except for COW pages).
1803 : : * This is ensured by core vm only modifying these page table entries using
1804 : : * functions that don't touch caching- or encryption bits, using pte_modify()
1805 : : * if needed. (See for example mprotect()).
1806 : : * Also when new page-table entries are created, this is only done using the
1807 : : * fault() callback, and never using the value of vma->vm_page_prot,
1808 : : * except for page-table entries that point to anonymous pages as the result
1809 : : * of COW.
1810 : : *
1811 : : * Context: Process context. May allocate using %GFP_KERNEL.
1812 : : * Return: vm_fault_t value.
1813 : : */
1814 : 0 : vm_fault_t vmf_insert_mixed_prot(struct vm_area_struct *vma, unsigned long addr,
1815 : : pfn_t pfn, pgprot_t pgprot)
1816 : : {
1817 : 0 : return __vm_insert_mixed(vma, addr, pfn, pgprot, false);
1818 : : }
1819 : : EXPORT_SYMBOL(vmf_insert_mixed_prot);
1820 : :
1821 : 0 : vm_fault_t vmf_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1822 : : pfn_t pfn)
1823 : : {
1824 : 0 : return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, false);
1825 : : }
1826 : : EXPORT_SYMBOL(vmf_insert_mixed);
1827 : :
1828 : : /*
1829 : : * If the insertion of PTE failed because someone else already added a
1830 : : * different entry in the mean time, we treat that as success as we assume
1831 : : * the same entry was actually inserted.
1832 : : */
1833 : 0 : vm_fault_t vmf_insert_mixed_mkwrite(struct vm_area_struct *vma,
1834 : : unsigned long addr, pfn_t pfn)
1835 : : {
1836 : 0 : return __vm_insert_mixed(vma, addr, pfn, vma->vm_page_prot, true);
1837 : : }
1838 : : EXPORT_SYMBOL(vmf_insert_mixed_mkwrite);
1839 : :
1840 : : /*
1841 : : * maps a range of physical memory into the requested pages. the old
1842 : : * mappings are removed. any references to nonexistent pages results
1843 : : * in null mappings (currently treated as "copy-on-access")
1844 : : */
1845 : 0 : static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1846 : : unsigned long addr, unsigned long end,
1847 : : unsigned long pfn, pgprot_t prot)
1848 : : {
1849 : 0 : pte_t *pte;
1850 : 0 : spinlock_t *ptl;
1851 : 0 : int err = 0;
1852 : :
1853 [ # # # # : 0 : pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
# # ]
1854 [ # # ]: 0 : if (!pte)
1855 : 0 : return -ENOMEM;
1856 : 0 : arch_enter_lazy_mmu_mode();
1857 : 0 : do {
1858 [ # # ]: 0 : BUG_ON(!pte_none(*pte));
1859 [ # # ]: 0 : if (!pfn_modify_allowed(pfn, prot)) {
1860 : : err = -EACCES;
1861 : : break;
1862 : : }
1863 [ # # ]: 0 : set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
1864 : 0 : pfn++;
1865 [ # # ]: 0 : } while (pte++, addr += PAGE_SIZE, addr != end);
1866 : 0 : arch_leave_lazy_mmu_mode();
1867 : 0 : pte_unmap_unlock(pte - 1, ptl);
1868 : 0 : return err;
1869 : : }
1870 : :
1871 : 0 : static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1872 : : unsigned long addr, unsigned long end,
1873 : : unsigned long pfn, pgprot_t prot)
1874 : : {
1875 : 0 : pmd_t *pmd;
1876 : 0 : unsigned long next;
1877 : 0 : int err;
1878 : :
1879 : 0 : pfn -= addr >> PAGE_SHIFT;
1880 : 0 : pmd = pmd_alloc(mm, pud, addr);
1881 [ # # ]: 0 : if (!pmd)
1882 : : return -ENOMEM;
1883 : 0 : VM_BUG_ON(pmd_trans_huge(*pmd));
1884 : 0 : do {
1885 [ # # ]: 0 : next = pmd_addr_end(addr, end);
1886 : 0 : err = remap_pte_range(mm, pmd, addr, next,
1887 : 0 : pfn + (addr >> PAGE_SHIFT), prot);
1888 [ # # ]: 0 : if (err)
1889 : 0 : return err;
1890 [ # # ]: 0 : } while (pmd++, addr = next, addr != end);
1891 : : return 0;
1892 : : }
1893 : :
1894 : 0 : static inline int remap_pud_range(struct mm_struct *mm, p4d_t *p4d,
1895 : : unsigned long addr, unsigned long end,
1896 : : unsigned long pfn, pgprot_t prot)
1897 : : {
1898 : 0 : pud_t *pud;
1899 : 0 : unsigned long next;
1900 : 0 : int err;
1901 : :
1902 : 0 : pfn -= addr >> PAGE_SHIFT;
1903 : 0 : pud = pud_alloc(mm, p4d, addr);
1904 [ # # ]: 0 : if (!pud)
1905 : : return -ENOMEM;
1906 : 0 : do {
1907 [ # # ]: 0 : next = pud_addr_end(addr, end);
1908 : 0 : err = remap_pmd_range(mm, pud, addr, next,
1909 : 0 : pfn + (addr >> PAGE_SHIFT), prot);
1910 [ # # ]: 0 : if (err)
1911 : 0 : return err;
1912 [ # # ]: 0 : } while (pud++, addr = next, addr != end);
1913 : : return 0;
1914 : : }
1915 : :
1916 : 0 : static inline int remap_p4d_range(struct mm_struct *mm, pgd_t *pgd,
1917 : : unsigned long addr, unsigned long end,
1918 : : unsigned long pfn, pgprot_t prot)
1919 : : {
1920 : 0 : p4d_t *p4d;
1921 : 0 : unsigned long next;
1922 : 0 : int err;
1923 : :
1924 : 0 : pfn -= addr >> PAGE_SHIFT;
1925 : 0 : p4d = p4d_alloc(mm, pgd, addr);
1926 [ # # ]: 0 : if (!p4d)
1927 : : return -ENOMEM;
1928 : 0 : do {
1929 [ # # ]: 0 : next = p4d_addr_end(addr, end);
1930 : 0 : err = remap_pud_range(mm, p4d, addr, next,
1931 : 0 : pfn + (addr >> PAGE_SHIFT), prot);
1932 [ # # ]: 0 : if (err)
1933 : 0 : return err;
1934 [ # # ]: 0 : } while (p4d++, addr = next, addr != end);
1935 : : return 0;
1936 : : }
1937 : :
1938 : : /**
1939 : : * remap_pfn_range - remap kernel memory to userspace
1940 : : * @vma: user vma to map to
1941 : : * @addr: target user address to start at
1942 : : * @pfn: physical address of kernel memory
1943 : : * @size: size of map area
1944 : : * @prot: page protection flags for this mapping
1945 : : *
1946 : : * Note: this is only safe if the mm semaphore is held when called.
1947 : : *
1948 : : * Return: %0 on success, negative error code otherwise.
1949 : : */
1950 : 0 : int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1951 : : unsigned long pfn, unsigned long size, pgprot_t prot)
1952 : : {
1953 : 0 : pgd_t *pgd;
1954 : 0 : unsigned long next;
1955 : 0 : unsigned long end = addr + PAGE_ALIGN(size);
1956 : 0 : struct mm_struct *mm = vma->vm_mm;
1957 : 0 : unsigned long remap_pfn = pfn;
1958 : 0 : int err;
1959 : :
1960 : : /*
1961 : : * Physically remapped pages are special. Tell the
1962 : : * rest of the world about it:
1963 : : * VM_IO tells people not to look at these pages
1964 : : * (accesses can have side effects).
1965 : : * VM_PFNMAP tells the core MM that the base pages are just
1966 : : * raw PFN mappings, and do not have a "struct page" associated
1967 : : * with them.
1968 : : * VM_DONTEXPAND
1969 : : * Disable vma merging and expanding with mremap().
1970 : : * VM_DONTDUMP
1971 : : * Omit vma from core dump, even when VM_IO turned off.
1972 : : *
1973 : : * There's a horrible special case to handle copy-on-write
1974 : : * behaviour that some programs depend on. We mark the "original"
1975 : : * un-COW'ed pages by matching them up with "vma->vm_pgoff".
1976 : : * See vm_normal_page() for details.
1977 : : */
1978 [ # # ]: 0 : if (is_cow_mapping(vma->vm_flags)) {
1979 [ # # # # ]: 0 : if (addr != vma->vm_start || end != vma->vm_end)
1980 : : return -EINVAL;
1981 : 0 : vma->vm_pgoff = pfn;
1982 : : }
1983 : :
1984 : 0 : err = track_pfn_remap(vma, &prot, remap_pfn, addr, PAGE_ALIGN(size));
1985 [ # # ]: 0 : if (err)
1986 : : return -EINVAL;
1987 : :
1988 : 0 : vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
1989 : :
1990 [ # # ]: 0 : BUG_ON(addr >= end);
1991 : 0 : pfn -= addr >> PAGE_SHIFT;
1992 : 0 : pgd = pgd_offset(mm, addr);
1993 : 0 : flush_cache_range(vma, addr, end);
1994 : 0 : do {
1995 [ # # ]: 0 : next = pgd_addr_end(addr, end);
1996 : 0 : err = remap_p4d_range(mm, pgd, addr, next,
1997 : 0 : pfn + (addr >> PAGE_SHIFT), prot);
1998 [ # # ]: 0 : if (err)
1999 : : break;
2000 [ # # ]: 0 : } while (pgd++, addr = next, addr != end);
2001 : :
2002 [ # # ]: 0 : if (err)
2003 : 0 : untrack_pfn(vma, remap_pfn, PAGE_ALIGN(size));
2004 : :
2005 : : return err;
2006 : : }
2007 : : EXPORT_SYMBOL(remap_pfn_range);
2008 : :
2009 : : /**
2010 : : * vm_iomap_memory - remap memory to userspace
2011 : : * @vma: user vma to map to
2012 : : * @start: start of area
2013 : : * @len: size of area
2014 : : *
2015 : : * This is a simplified io_remap_pfn_range() for common driver use. The
2016 : : * driver just needs to give us the physical memory range to be mapped,
2017 : : * we'll figure out the rest from the vma information.
2018 : : *
2019 : : * NOTE! Some drivers might want to tweak vma->vm_page_prot first to get
2020 : : * whatever write-combining details or similar.
2021 : : *
2022 : : * Return: %0 on success, negative error code otherwise.
2023 : : */
2024 : 0 : int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
2025 : : {
2026 : 0 : unsigned long vm_len, pfn, pages;
2027 : :
2028 : : /* Check that the physical memory area passed in looks valid */
2029 [ # # ]: 0 : if (start + len < start)
2030 : : return -EINVAL;
2031 : : /*
2032 : : * You *really* shouldn't map things that aren't page-aligned,
2033 : : * but we've historically allowed it because IO memory might
2034 : : * just have smaller alignment.
2035 : : */
2036 : 0 : len += start & ~PAGE_MASK;
2037 : 0 : pfn = start >> PAGE_SHIFT;
2038 : 0 : pages = (len + ~PAGE_MASK) >> PAGE_SHIFT;
2039 [ # # ]: 0 : if (pfn + pages < pfn)
2040 : : return -EINVAL;
2041 : :
2042 : : /* We start the mapping 'vm_pgoff' pages into the area */
2043 [ # # ]: 0 : if (vma->vm_pgoff > pages)
2044 : : return -EINVAL;
2045 : 0 : pfn += vma->vm_pgoff;
2046 : 0 : pages -= vma->vm_pgoff;
2047 : :
2048 : : /* Can we fit all of the mapping? */
2049 : 0 : vm_len = vma->vm_end - vma->vm_start;
2050 [ # # ]: 0 : if (vm_len >> PAGE_SHIFT > pages)
2051 : : return -EINVAL;
2052 : :
2053 : : /* Ok, let it rip */
2054 : 0 : return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
2055 : : }
2056 : : EXPORT_SYMBOL(vm_iomap_memory);
2057 : :
2058 : 0 : static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
2059 : : unsigned long addr, unsigned long end,
2060 : : pte_fn_t fn, void *data, bool create)
2061 : : {
2062 : 0 : pte_t *pte;
2063 : 0 : int err = 0;
2064 : 0 : spinlock_t *uninitialized_var(ptl);
2065 : :
2066 [ # # ]: 0 : if (create) {
2067 : 0 : pte = (mm == &init_mm) ?
2068 [ # # # # : 0 : pte_alloc_kernel(pmd, addr) :
# # ]
2069 [ # # # # : 0 : pte_alloc_map_lock(mm, pmd, addr, &ptl);
# # ]
2070 [ # # ]: 0 : if (!pte)
2071 : : return -ENOMEM;
2072 : : } else {
2073 : 0 : pte = (mm == &init_mm) ?
2074 [ # # ]: 0 : pte_offset_kernel(pmd, addr) :
2075 [ # # ]: 0 : pte_offset_map_lock(mm, pmd, addr, &ptl);
2076 : : }
2077 : :
2078 [ # # ]: 0 : BUG_ON(pmd_huge(*pmd));
2079 : :
2080 : 0 : arch_enter_lazy_mmu_mode();
2081 : :
2082 : 0 : do {
2083 [ # # # # ]: 0 : if (create || !pte_none(*pte)) {
2084 : 0 : err = fn(pte++, addr, data);
2085 [ # # ]: 0 : if (err)
2086 : : break;
2087 : : }
2088 [ # # ]: 0 : } while (addr += PAGE_SIZE, addr != end);
2089 : :
2090 : 0 : arch_leave_lazy_mmu_mode();
2091 : :
2092 [ # # ]: 0 : if (mm != &init_mm)
2093 : 0 : pte_unmap_unlock(pte-1, ptl);
2094 : : return err;
2095 : : }
2096 : :
2097 : 0 : static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
2098 : : unsigned long addr, unsigned long end,
2099 : : pte_fn_t fn, void *data, bool create)
2100 : : {
2101 : 0 : pmd_t *pmd;
2102 : 0 : unsigned long next;
2103 : 0 : int err = 0;
2104 : :
2105 [ # # ]: 0 : BUG_ON(pud_huge(*pud));
2106 : :
2107 [ # # ]: 0 : if (create) {
2108 : 0 : pmd = pmd_alloc(mm, pud, addr);
2109 [ # # ]: 0 : if (!pmd)
2110 : : return -ENOMEM;
2111 : : } else {
2112 [ # # ]: 0 : pmd = pmd_offset(pud, addr);
2113 : : }
2114 : 0 : do {
2115 [ # # ]: 0 : next = pmd_addr_end(addr, end);
2116 [ # # # # ]: 0 : if (create || !pmd_none_or_clear_bad(pmd)) {
2117 : 0 : err = apply_to_pte_range(mm, pmd, addr, next, fn, data,
2118 : : create);
2119 [ # # ]: 0 : if (err)
2120 : : break;
2121 : : }
2122 [ # # ]: 0 : } while (pmd++, addr = next, addr != end);
2123 : : return err;
2124 : : }
2125 : :
2126 : 0 : static int apply_to_pud_range(struct mm_struct *mm, p4d_t *p4d,
2127 : : unsigned long addr, unsigned long end,
2128 : : pte_fn_t fn, void *data, bool create)
2129 : : {
2130 : 0 : pud_t *pud;
2131 : 0 : unsigned long next;
2132 : 0 : int err = 0;
2133 : :
2134 [ # # ]: 0 : if (create) {
2135 : 0 : pud = pud_alloc(mm, p4d, addr);
2136 [ # # ]: 0 : if (!pud)
2137 : : return -ENOMEM;
2138 : : } else {
2139 : 0 : pud = pud_offset(p4d, addr);
2140 : : }
2141 : 0 : do {
2142 [ # # ]: 0 : next = pud_addr_end(addr, end);
2143 [ # # # # ]: 0 : if (create || !pud_none_or_clear_bad(pud)) {
2144 : 0 : err = apply_to_pmd_range(mm, pud, addr, next, fn, data,
2145 : : create);
2146 [ # # ]: 0 : if (err)
2147 : : break;
2148 : : }
2149 [ # # ]: 0 : } while (pud++, addr = next, addr != end);
2150 : : return err;
2151 : : }
2152 : :
2153 : 0 : static int apply_to_p4d_range(struct mm_struct *mm, pgd_t *pgd,
2154 : : unsigned long addr, unsigned long end,
2155 : : pte_fn_t fn, void *data, bool create)
2156 : : {
2157 : 0 : p4d_t *p4d;
2158 : 0 : unsigned long next;
2159 : 0 : int err = 0;
2160 : :
2161 [ # # ]: 0 : if (create) {
2162 : 0 : p4d = p4d_alloc(mm, pgd, addr);
2163 [ # # ]: 0 : if (!p4d)
2164 : : return -ENOMEM;
2165 : : } else {
2166 : 0 : p4d = p4d_offset(pgd, addr);
2167 : : }
2168 : 0 : do {
2169 [ # # ]: 0 : next = p4d_addr_end(addr, end);
2170 [ # # ]: 0 : if (create || !p4d_none_or_clear_bad(p4d)) {
2171 : 0 : err = apply_to_pud_range(mm, p4d, addr, next, fn, data,
2172 : : create);
2173 [ # # ]: 0 : if (err)
2174 : : break;
2175 : : }
2176 [ # # ]: 0 : } while (p4d++, addr = next, addr != end);
2177 : : return err;
2178 : : }
2179 : :
2180 : 0 : static int __apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2181 : : unsigned long size, pte_fn_t fn,
2182 : : void *data, bool create)
2183 : : {
2184 : 0 : pgd_t *pgd;
2185 : 0 : unsigned long next;
2186 : 0 : unsigned long end = addr + size;
2187 : 0 : int err = 0;
2188 : :
2189 [ # # # # ]: 0 : if (WARN_ON(addr >= end))
2190 : : return -EINVAL;
2191 : :
2192 : 0 : pgd = pgd_offset(mm, addr);
2193 : 0 : do {
2194 [ # # ]: 0 : next = pgd_addr_end(addr, end);
2195 [ # # # # ]: 0 : if (!create && pgd_none_or_clear_bad(pgd))
2196 : 0 : continue;
2197 : 0 : err = apply_to_p4d_range(mm, pgd, addr, next, fn, data, create);
2198 [ # # ]: 0 : if (err)
2199 : : break;
2200 [ # # ]: 0 : } while (pgd++, addr = next, addr != end);
2201 : :
2202 : : return err;
2203 : : }
2204 : :
2205 : : /*
2206 : : * Scan a region of virtual memory, filling in page tables as necessary
2207 : : * and calling a provided function on each leaf page table.
2208 : : */
2209 : 0 : int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
2210 : : unsigned long size, pte_fn_t fn, void *data)
2211 : : {
2212 : 0 : return __apply_to_page_range(mm, addr, size, fn, data, true);
2213 : : }
2214 : : EXPORT_SYMBOL_GPL(apply_to_page_range);
2215 : :
2216 : : /*
2217 : : * Scan a region of virtual memory, calling a provided function on
2218 : : * each leaf page table where it exists.
2219 : : *
2220 : : * Unlike apply_to_page_range, this does _not_ fill in page tables
2221 : : * where they are absent.
2222 : : */
2223 : 0 : int apply_to_existing_page_range(struct mm_struct *mm, unsigned long addr,
2224 : : unsigned long size, pte_fn_t fn, void *data)
2225 : : {
2226 : 0 : return __apply_to_page_range(mm, addr, size, fn, data, false);
2227 : : }
2228 : : EXPORT_SYMBOL_GPL(apply_to_existing_page_range);
2229 : :
2230 : : /*
2231 : : * handle_pte_fault chooses page fault handler according to an entry which was
2232 : : * read non-atomically. Before making any commitment, on those architectures
2233 : : * or configurations (e.g. i386 with PAE) which might give a mix of unmatched
2234 : : * parts, do_swap_page must check under lock before unmapping the pte and
2235 : : * proceeding (but do_wp_page is only called after already making such a check;
2236 : : * and do_anonymous_page can safely check later on).
2237 : : */
2238 : 0 : static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
2239 : : pte_t *page_table, pte_t orig_pte)
2240 : : {
2241 : 0 : int same = 1;
2242 : : #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPTION)
2243 : 0 : if (sizeof(pte_t) > sizeof(unsigned long)) {
2244 : : spinlock_t *ptl = pte_lockptr(mm, pmd);
2245 : : spin_lock(ptl);
2246 : : same = pte_same(*page_table, orig_pte);
2247 : : spin_unlock(ptl);
2248 : : }
2249 : : #endif
2250 : 0 : pte_unmap(page_table);
2251 : 0 : return same;
2252 : : }
2253 : :
2254 : 181188 : static inline bool cow_user_page(struct page *dst, struct page *src,
2255 : : struct vm_fault *vmf)
2256 : : {
2257 : 181188 : bool ret;
2258 : 181188 : void *kaddr;
2259 : 181188 : void __user *uaddr;
2260 : 181188 : bool locked = false;
2261 : 181188 : struct vm_area_struct *vma = vmf->vma;
2262 : 181188 : struct mm_struct *mm = vma->vm_mm;
2263 : 181188 : unsigned long addr = vmf->address;
2264 : :
2265 : 181188 : debug_dma_assert_idle(src);
2266 : :
2267 [ + - ]: 181188 : if (likely(src)) {
2268 : 181188 : copy_user_highpage(dst, src, addr, vma);
2269 : 181188 : return true;
2270 : : }
2271 : :
2272 : : /*
2273 : : * If the source page was a PFN mapping, we don't have
2274 : : * a "struct page" for it. We do a best-effort copy by
2275 : : * just copying from the original user address. If that
2276 : : * fails, we just zero-fill it. Live with it.
2277 : : */
2278 : 0 : kaddr = kmap_atomic(dst);
2279 : 0 : uaddr = (void __user *)(addr & PAGE_MASK);
2280 : :
2281 : : /*
2282 : : * On architectures with software "accessed" bits, we would
2283 : : * take a double page fault, so mark it accessed here.
2284 : : */
2285 : 0 : if (arch_faults_on_old_pte() && !pte_young(vmf->orig_pte)) {
2286 : : pte_t entry;
2287 : :
2288 : : vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl);
2289 : : locked = true;
2290 : : if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) {
2291 : : /*
2292 : : * Other thread has already handled the fault
2293 : : * and we don't need to do anything. If it's
2294 : : * not the case, the fault will be triggered
2295 : : * again on the same address.
2296 : : */
2297 : : ret = false;
2298 : : goto pte_unlock;
2299 : : }
2300 : :
2301 : : entry = pte_mkyoung(vmf->orig_pte);
2302 : : if (ptep_set_access_flags(vma, addr, vmf->pte, entry, 0))
2303 : : update_mmu_cache(vma, addr, vmf->pte);
2304 : : }
2305 : :
2306 : : /*
2307 : : * This really shouldn't fail, because the page is there
2308 : : * in the page tables. But it might just be unreadable,
2309 : : * in which case we just give up and fill the result with
2310 : : * zeroes.
2311 : : */
2312 [ # # ]: 0 : if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) {
2313 : 0 : if (locked)
2314 : : goto warn;
2315 : :
2316 : : /* Re-validate under PTL if the page is still mapped */
2317 [ # # ]: 0 : vmf->pte = pte_offset_map_lock(mm, vmf->pmd, addr, &vmf->ptl);
2318 : 0 : locked = true;
2319 [ # # ]: 0 : if (!likely(pte_same(*vmf->pte, vmf->orig_pte))) {
2320 : : /* The PTE changed under us. Retry page fault. */
2321 : 0 : ret = false;
2322 : 0 : goto pte_unlock;
2323 : : }
2324 : :
2325 : : /*
2326 : : * The same page can be mapped back since last copy attampt.
2327 : : * Try to copy again under PTL.
2328 : : */
2329 [ # # ]: 0 : if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) {
2330 : : /*
2331 : : * Give a warn in case there can be some obscure
2332 : : * use-case
2333 : : */
2334 : 0 : warn:
2335 : 0 : WARN_ON_ONCE(1);
2336 : 0 : clear_page(kaddr);
2337 : : }
2338 : : }
2339 : :
2340 : 0 : ret = true;
2341 : :
2342 : : pte_unlock:
2343 : 0 : if (locked)
2344 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2345 : 0 : kunmap_atomic(kaddr);
2346 : 0 : flush_dcache_page(dst);
2347 : :
2348 : 0 : return ret;
2349 : : }
2350 : :
2351 : 1155182 : static gfp_t __get_fault_gfp_mask(struct vm_area_struct *vma)
2352 : : {
2353 : 1155182 : struct file *vm_file = vma->vm_file;
2354 : :
2355 : 1155182 : if (vm_file)
2356 : 810547 : return mapping_gfp_mask(vm_file->f_mapping) | __GFP_FS | __GFP_IO;
2357 : :
2358 : : /*
2359 : : * Special mappings (e.g. VDSO) do not have any file so fake
2360 : : * a default GFP_KERNEL for them.
2361 : : */
2362 : : return GFP_KERNEL;
2363 : : }
2364 : :
2365 : : /*
2366 : : * Notify the address space that the page is about to become writable so that
2367 : : * it can prohibit this or wait for the page to get into an appropriate state.
2368 : : *
2369 : : * We do this without the lock held, so that it can sleep if it needs to.
2370 : : */
2371 : 0 : static vm_fault_t do_page_mkwrite(struct vm_fault *vmf)
2372 : : {
2373 : 0 : vm_fault_t ret;
2374 : 0 : struct page *page = vmf->page;
2375 : 0 : unsigned int old_flags = vmf->flags;
2376 : :
2377 : 0 : vmf->flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2378 : :
2379 [ # # ]: 0 : if (vmf->vma->vm_file &&
2380 [ # # ]: 0 : IS_SWAPFILE(vmf->vma->vm_file->f_mapping->host))
2381 : : return VM_FAULT_SIGBUS;
2382 : :
2383 : 0 : ret = vmf->vma->vm_ops->page_mkwrite(vmf);
2384 : : /* Restore original flags so that caller is not surprised */
2385 : 0 : vmf->flags = old_flags;
2386 [ # # ]: 0 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2387 : : return ret;
2388 [ # # ]: 0 : if (unlikely(!(ret & VM_FAULT_LOCKED))) {
2389 : 0 : lock_page(page);
2390 [ # # ]: 0 : if (!page->mapping) {
2391 : 0 : unlock_page(page);
2392 : 0 : return 0; /* retry */
2393 : : }
2394 : 0 : ret |= VM_FAULT_LOCKED;
2395 : : } else
2396 : : VM_BUG_ON_PAGE(!PageLocked(page), page);
2397 : : return ret;
2398 : : }
2399 : :
2400 : : /*
2401 : : * Handle dirtying of a page in shared file mapping on a write fault.
2402 : : *
2403 : : * The function expects the page to be locked and unlocks it.
2404 : : */
2405 : 1471 : static vm_fault_t fault_dirty_shared_page(struct vm_fault *vmf)
2406 : : {
2407 : 1471 : struct vm_area_struct *vma = vmf->vma;
2408 : 1471 : struct address_space *mapping;
2409 : 1471 : struct page *page = vmf->page;
2410 : 1471 : bool dirtied;
2411 [ + - + - ]: 1471 : bool page_mkwrite = vma->vm_ops && vma->vm_ops->page_mkwrite;
2412 : :
2413 : 1471 : dirtied = set_page_dirty(page);
2414 : 1471 : VM_BUG_ON_PAGE(PageAnon(page), page);
2415 : : /*
2416 : : * Take a local copy of the address_space - page.mapping may be zeroed
2417 : : * by truncate after unlock_page(). The address_space itself remains
2418 : : * pinned by vma->vm_file's reference. We rely on unlock_page()'s
2419 : : * release semantics to prevent the compiler from undoing this copying.
2420 : : */
2421 : 1471 : mapping = page_rmapping(page);
2422 : 1471 : unlock_page(page);
2423 : :
2424 [ + - ]: 1471 : if (!page_mkwrite)
2425 : 1471 : file_update_time(vma->vm_file);
2426 : :
2427 : : /*
2428 : : * Throttle page dirtying rate down to writeback speed.
2429 : : *
2430 : : * mapping may be NULL here because some device drivers do not
2431 : : * set page.mapping but still dirty their pages
2432 : : *
2433 : : * Drop the mmap_sem before waiting on IO, if we can. The file
2434 : : * is pinning the mapping, as per above.
2435 : : */
2436 [ - + - - ]: 1471 : if ((dirtied || page_mkwrite) && mapping) {
2437 : 0 : struct file *fpin;
2438 : :
2439 : 0 : fpin = maybe_unlock_mmap_for_io(vmf, NULL);
2440 : 0 : balance_dirty_pages_ratelimited(mapping);
2441 [ # # ]: 0 : if (fpin) {
2442 : 0 : fput(fpin);
2443 : 0 : return VM_FAULT_RETRY;
2444 : : }
2445 : : }
2446 : :
2447 : : return 0;
2448 : : }
2449 : :
2450 : : /*
2451 : : * Handle write page faults for pages that can be reused in the current vma
2452 : : *
2453 : : * This can happen either due to the mapping being with the VM_SHARED flag,
2454 : : * or due to us being the last reference standing to the page. In either
2455 : : * case, all we need to do here is to mark the page as writable and update
2456 : : * any related book-keeping.
2457 : : */
2458 : 135535 : static inline void wp_page_reuse(struct vm_fault *vmf)
2459 : : __releases(vmf->ptl)
2460 : : {
2461 : 135535 : struct vm_area_struct *vma = vmf->vma;
2462 : 135535 : struct page *page = vmf->page;
2463 : 135535 : pte_t entry;
2464 : : /*
2465 : : * Clear the pages cpupid information as the existing
2466 : : * information potentially belongs to a now completely
2467 : : * unrelated process.
2468 : : */
2469 : 135535 : if (page)
2470 : : page_cpupid_xchg_last(page, (1 << LAST_CPUPID_SHIFT) - 1);
2471 : :
2472 [ + - ]: 135535 : flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
2473 [ + - ]: 135535 : entry = pte_mkyoung(vmf->orig_pte);
2474 [ + - ]: 135535 : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2475 : 135535 : if (ptep_set_access_flags(vma, vmf->address, vmf->pte, entry, 1))
2476 : : update_mmu_cache(vma, vmf->address, vmf->pte);
2477 : 135535 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2478 : 135535 : }
2479 : :
2480 : : /*
2481 : : * Handle the case of a page which we actually need to copy to a new page.
2482 : : *
2483 : : * Called with mmap_sem locked and the old page referenced, but
2484 : : * without the ptl held.
2485 : : *
2486 : : * High level logic flow:
2487 : : *
2488 : : * - Allocate a page, copy the content of the old page to the new one.
2489 : : * - Handle book keeping and accounting - cgroups, mmu-notifiers, etc.
2490 : : * - Take the PTL. If the pte changed, bail out and release the allocated page
2491 : : * - If the pte is still the way we remember it, update the page table and all
2492 : : * relevant references. This includes dropping the reference the page-table
2493 : : * held to the old page, as well as updating the rmap.
2494 : : * - In any case, unlock the PTL and drop the reference we took to the old page.
2495 : : */
2496 : 191154 : static vm_fault_t wp_page_copy(struct vm_fault *vmf)
2497 : : {
2498 : 191154 : struct vm_area_struct *vma = vmf->vma;
2499 : 191154 : struct mm_struct *mm = vma->vm_mm;
2500 : 191154 : struct page *old_page = vmf->page;
2501 : 191154 : struct page *new_page = NULL;
2502 : 191154 : pte_t entry;
2503 : 191154 : int page_copied = 0;
2504 : 191154 : struct mem_cgroup *memcg;
2505 : 191154 : struct mmu_notifier_range range;
2506 : :
2507 [ + + - + ]: 194443 : if (unlikely(anon_vma_prepare(vma)))
2508 : 0 : goto oom;
2509 : :
2510 [ + - + + ]: 382308 : if (is_zero_pfn(pte_pfn(vmf->orig_pte))) {
2511 : 9966 : new_page = alloc_zeroed_user_highpage_movable(vma,
2512 : : vmf->address);
2513 [ - + ]: 9966 : if (!new_page)
2514 : 0 : goto oom;
2515 : : } else {
2516 : 181188 : new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
2517 : : vmf->address);
2518 [ - + ]: 181188 : if (!new_page)
2519 : 0 : goto oom;
2520 : :
2521 [ - + ]: 181188 : if (!cow_user_page(new_page, old_page, vmf)) {
2522 : : /*
2523 : : * COW failed, if the fault was solved by other,
2524 : : * it's fine. If not, userspace would re-fault on
2525 : : * the same address and we will handle the fault
2526 : : * from the second attempt.
2527 : : */
2528 : 0 : put_page(new_page);
2529 [ # # ]: 0 : if (old_page)
2530 : 0 : put_page(old_page);
2531 : 0 : return 0;
2532 : : }
2533 : : }
2534 : :
2535 : 191154 : if (mem_cgroup_try_charge_delay(new_page, mm, GFP_KERNEL, &memcg, false))
2536 : : goto oom_free_new;
2537 : :
2538 : 191154 : __SetPageUptodate(new_page);
2539 : :
2540 : 191154 : mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
2541 : : vmf->address & PAGE_MASK,
2542 : 191154 : (vmf->address & PAGE_MASK) + PAGE_SIZE);
2543 : 191154 : mmu_notifier_invalidate_range_start(&range);
2544 : :
2545 : : /*
2546 : : * Re-check the pte - we dropped the lock
2547 : : */
2548 [ + - ]: 382308 : vmf->pte = pte_offset_map_lock(mm, vmf->pmd, vmf->address, &vmf->ptl);
2549 [ + - ]: 191154 : if (likely(pte_same(*vmf->pte, vmf->orig_pte))) {
2550 [ + + ]: 191154 : if (old_page) {
2551 [ - + + + ]: 181188 : if (!PageAnon(old_page)) {
2552 : 102422 : dec_mm_counter_fast(mm,
2553 : : mm_counter_file(old_page));
2554 : 102422 : inc_mm_counter_fast(mm, MM_ANONPAGES);
2555 : : }
2556 : : } else {
2557 : 9966 : inc_mm_counter_fast(mm, MM_ANONPAGES);
2558 : : }
2559 [ + - ]: 191154 : flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte));
2560 [ + - ]: 191154 : entry = mk_pte(new_page, vma->vm_page_prot);
2561 [ + - ]: 191154 : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2562 : : /*
2563 : : * Clear the pte entry and flush it first, before updating the
2564 : : * pte with the new entry. This will avoid a race condition
2565 : : * seen in the presence of one thread doing SMC and another
2566 : : * thread doing COW.
2567 : : */
2568 [ - + ]: 191154 : ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
2569 : 191154 : page_add_new_anon_rmap(new_page, vma, vmf->address, false);
2570 : 191154 : mem_cgroup_commit_charge(new_page, memcg, false, false);
2571 : 191154 : lru_cache_add_active_or_unevictable(new_page, vma);
2572 : : /*
2573 : : * We call the notify macro here because, when using secondary
2574 : : * mmu page tables (such as kvm shadow page tables), we want the
2575 : : * new page to be mapped directly into the secondary page table.
2576 : : */
2577 [ - + + + ]: 191154 : set_pte_at_notify(mm, vmf->address, vmf->pte, entry);
2578 [ + + ]: 191154 : update_mmu_cache(vma, vmf->address, vmf->pte);
2579 [ + + ]: 191154 : if (old_page) {
2580 : : /*
2581 : : * Only after switching the pte to the new page may
2582 : : * we remove the mapcount here. Otherwise another
2583 : : * process may come and find the rmap count decremented
2584 : : * before the pte is switched to the new page, and
2585 : : * "reuse" the old page writing into it while our pte
2586 : : * here still points into it and can be read by other
2587 : : * threads.
2588 : : *
2589 : : * The critical issue is to order this
2590 : : * page_remove_rmap with the ptp_clear_flush above.
2591 : : * Those stores are ordered by (if nothing else,)
2592 : : * the barrier present in the atomic_add_negative
2593 : : * in page_remove_rmap.
2594 : : *
2595 : : * Then the TLB flush in ptep_clear_flush ensures that
2596 : : * no process can access the old page before the
2597 : : * decremented mapcount is visible. And the old page
2598 : : * cannot be reused until after the decremented
2599 : : * mapcount is visible. So transitively, TLBs to
2600 : : * old page will be flushed before it can be reused.
2601 : : */
2602 : 181188 : page_remove_rmap(old_page, false);
2603 : : }
2604 : :
2605 : : /* Free the old page.. */
2606 : : new_page = old_page;
2607 : : page_copied = 1;
2608 : : } else {
2609 : : mem_cgroup_cancel_charge(new_page, memcg, false);
2610 : : }
2611 : :
2612 [ + + ]: 191154 : if (new_page)
2613 : 181188 : put_page(new_page);
2614 : :
2615 : 191154 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2616 : : /*
2617 : : * No need to double call mmu_notifier->invalidate_range() callback as
2618 : : * the above ptep_clear_flush_notify() did already call it.
2619 : : */
2620 [ - + ]: 191154 : mmu_notifier_invalidate_range_only_end(&range);
2621 [ + + ]: 191154 : if (old_page) {
2622 : : /*
2623 : : * Don't let another task, with possibly unlocked vma,
2624 : : * keep the mlocked page.
2625 : : */
2626 [ + - - + ]: 181188 : if (page_copied && (vma->vm_flags & VM_LOCKED)) {
2627 : 0 : lock_page(old_page); /* LRU manipulation */
2628 [ # # # # ]: 0 : if (PageMlocked(old_page))
2629 : 0 : munlock_vma_page(old_page);
2630 : 0 : unlock_page(old_page);
2631 : : }
2632 : 181188 : put_page(old_page);
2633 : : }
2634 [ - + ]: 191154 : return page_copied ? VM_FAULT_WRITE : 0;
2635 : : oom_free_new:
2636 : : put_page(new_page);
2637 : 0 : oom:
2638 [ # # ]: 0 : if (old_page)
2639 : 0 : put_page(old_page);
2640 : : return VM_FAULT_OOM;
2641 : : }
2642 : :
2643 : : /**
2644 : : * finish_mkwrite_fault - finish page fault for a shared mapping, making PTE
2645 : : * writeable once the page is prepared
2646 : : *
2647 : : * @vmf: structure describing the fault
2648 : : *
2649 : : * This function handles all that is needed to finish a write page fault in a
2650 : : * shared mapping due to PTE being read-only once the mapped page is prepared.
2651 : : * It handles locking of PTE and modifying it.
2652 : : *
2653 : : * The function expects the page to be locked or other protection against
2654 : : * concurrent faults / writeback (such as DAX radix tree locks).
2655 : : *
2656 : : * Return: %VM_FAULT_WRITE on success, %0 when PTE got changed before
2657 : : * we acquired PTE lock.
2658 : : */
2659 : 0 : vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf)
2660 : : {
2661 [ # # ]: 0 : WARN_ON_ONCE(!(vmf->vma->vm_flags & VM_SHARED));
2662 [ # # ]: 0 : vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm, vmf->pmd, vmf->address,
2663 : : &vmf->ptl);
2664 : : /*
2665 : : * We might have raced with another page fault while we released the
2666 : : * pte_offset_map_lock.
2667 : : */
2668 [ # # ]: 0 : if (!pte_same(*vmf->pte, vmf->orig_pte)) {
2669 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2670 : 0 : return VM_FAULT_NOPAGE;
2671 : : }
2672 : 0 : wp_page_reuse(vmf);
2673 : 0 : return 0;
2674 : : }
2675 : :
2676 : : /*
2677 : : * Handle write page faults for VM_MIXEDMAP or VM_PFNMAP for a VM_SHARED
2678 : : * mapping
2679 : : */
2680 : 0 : static vm_fault_t wp_pfn_shared(struct vm_fault *vmf)
2681 : : {
2682 : 0 : struct vm_area_struct *vma = vmf->vma;
2683 : :
2684 [ # # # # ]: 0 : if (vma->vm_ops && vma->vm_ops->pfn_mkwrite) {
2685 : 0 : vm_fault_t ret;
2686 : :
2687 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2688 : 0 : vmf->flags |= FAULT_FLAG_MKWRITE;
2689 : 0 : ret = vma->vm_ops->pfn_mkwrite(vmf);
2690 [ # # ]: 0 : if (ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))
2691 : : return ret;
2692 : 0 : return finish_mkwrite_fault(vmf);
2693 : : }
2694 : 0 : wp_page_reuse(vmf);
2695 : 0 : return VM_FAULT_WRITE;
2696 : : }
2697 : :
2698 : 0 : static vm_fault_t wp_page_shared(struct vm_fault *vmf)
2699 : : __releases(vmf->ptl)
2700 : : {
2701 : 0 : struct vm_area_struct *vma = vmf->vma;
2702 : 0 : vm_fault_t ret = VM_FAULT_WRITE;
2703 : :
2704 [ # # ]: 0 : get_page(vmf->page);
2705 : :
2706 [ # # # # ]: 0 : if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
2707 : 0 : vm_fault_t tmp;
2708 : :
2709 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2710 : 0 : tmp = do_page_mkwrite(vmf);
2711 [ # # # # ]: 0 : if (unlikely(!tmp || (tmp &
2712 : : (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
2713 : 0 : put_page(vmf->page);
2714 : 0 : return tmp;
2715 : : }
2716 : 0 : tmp = finish_mkwrite_fault(vmf);
2717 [ # # ]: 0 : if (unlikely(tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2718 : 0 : unlock_page(vmf->page);
2719 : 0 : put_page(vmf->page);
2720 : 0 : return tmp;
2721 : : }
2722 : : } else {
2723 : 0 : wp_page_reuse(vmf);
2724 : 0 : lock_page(vmf->page);
2725 : : }
2726 : 0 : ret |= fault_dirty_shared_page(vmf);
2727 : 0 : put_page(vmf->page);
2728 : :
2729 : 0 : return ret;
2730 : : }
2731 : :
2732 : : /*
2733 : : * This routine handles present pages, when users try to write
2734 : : * to a shared page. It is done by copying the page to a new address
2735 : : * and decrementing the shared-page counter for the old page.
2736 : : *
2737 : : * Note that this routine assumes that the protection checks have been
2738 : : * done by the caller (the low-level page fault routine in most cases).
2739 : : * Thus we can safely just mark it writable once we've done any necessary
2740 : : * COW.
2741 : : *
2742 : : * We also mark the page dirty at this point even though the page will
2743 : : * change only once the write actually happens. This avoids a few races,
2744 : : * and potentially makes it more efficient.
2745 : : *
2746 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
2747 : : * but allow concurrent faults), with pte both mapped and locked.
2748 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
2749 : : */
2750 : 326689 : static vm_fault_t do_wp_page(struct vm_fault *vmf)
2751 : : __releases(vmf->ptl)
2752 : : {
2753 : 326689 : struct vm_area_struct *vma = vmf->vma;
2754 : :
2755 : 326689 : vmf->page = vm_normal_page(vma, vmf->address, vmf->orig_pte);
2756 [ + + ]: 326689 : if (!vmf->page) {
2757 : : /*
2758 : : * VM_MIXEDMAP !pfn_valid() case, or VM_SOFTDIRTY clear on a
2759 : : * VM_PFNMAP VMA.
2760 : : *
2761 : : * We should not cow pages in a shared writeable mapping.
2762 : : * Just mark the pages writable and/or call ops->pfn_mkwrite.
2763 : : */
2764 [ - + ]: 9966 : if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2765 : : (VM_WRITE|VM_SHARED))
2766 : 0 : return wp_pfn_shared(vmf);
2767 : :
2768 : 9966 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2769 : 9966 : return wp_page_copy(vmf);
2770 : : }
2771 : :
2772 : : /*
2773 : : * Take out anonymous pages first, anonymous shared vmas are
2774 : : * not dirty accountable.
2775 : : */
2776 [ - + + + ]: 316723 : if (PageAnon(vmf->page)) {
2777 : 214301 : int total_map_swapcount;
2778 [ - + ]: 214301 : if (PageKsm(vmf->page) && (PageSwapCache(vmf->page) ||
2779 : : page_count(vmf->page) != 1))
2780 : : goto copy;
2781 [ - + - + ]: 428602 : if (!trylock_page(vmf->page)) {
2782 [ # # ]: 0 : get_page(vmf->page);
2783 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2784 : 0 : lock_page(vmf->page);
2785 [ # # ]: 0 : vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
2786 : : vmf->address, &vmf->ptl);
2787 [ # # ]: 0 : if (!pte_same(*vmf->pte, vmf->orig_pte)) {
2788 : 0 : unlock_page(vmf->page);
2789 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2790 : 0 : put_page(vmf->page);
2791 : 135535 : return 0;
2792 : : }
2793 : 0 : put_page(vmf->page);
2794 : : }
2795 : 214301 : if (PageKsm(vmf->page)) {
2796 : : bool reused = reuse_ksm_page(vmf->page, vmf->vma,
2797 : : vmf->address);
2798 : : unlock_page(vmf->page);
2799 : : if (!reused)
2800 : : goto copy;
2801 : : wp_page_reuse(vmf);
2802 : : return VM_FAULT_WRITE;
2803 : : }
2804 [ + + ]: 214301 : if (reuse_swap_page(vmf->page, &total_map_swapcount)) {
2805 [ + - ]: 135535 : if (total_map_swapcount == 1) {
2806 : : /*
2807 : : * The page is all ours. Move it to
2808 : : * our anon_vma so the rmap code will
2809 : : * not search our parent or siblings.
2810 : : * Protected against the rmap code by
2811 : : * the page lock.
2812 : : */
2813 : 135535 : page_move_anon_rmap(vmf->page, vma);
2814 : : }
2815 : 135535 : unlock_page(vmf->page);
2816 : 135535 : wp_page_reuse(vmf);
2817 : 135535 : return VM_FAULT_WRITE;
2818 : : }
2819 : 78766 : unlock_page(vmf->page);
2820 [ - + ]: 102422 : } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2821 : : (VM_WRITE|VM_SHARED))) {
2822 : 0 : return wp_page_shared(vmf);
2823 : : }
2824 : 102422 : copy:
2825 : : /*
2826 : : * Ok, we need to copy. Oh, well..
2827 : : */
2828 [ - + ]: 181188 : get_page(vmf->page);
2829 : :
2830 : 181188 : pte_unmap_unlock(vmf->pte, vmf->ptl);
2831 : 181188 : return wp_page_copy(vmf);
2832 : : }
2833 : :
2834 : 0 : static void unmap_mapping_range_vma(struct vm_area_struct *vma,
2835 : : unsigned long start_addr, unsigned long end_addr,
2836 : : struct zap_details *details)
2837 : : {
2838 : 0 : zap_page_range_single(vma, start_addr, end_addr - start_addr, details);
2839 : : }
2840 : :
2841 : 0 : static inline void unmap_mapping_range_tree(struct rb_root_cached *root,
2842 : : struct zap_details *details)
2843 : : {
2844 : 0 : struct vm_area_struct *vma;
2845 : 0 : pgoff_t vba, vea, zba, zea;
2846 : :
2847 [ # # ]: 0 : vma_interval_tree_foreach(vma, root,
2848 : : details->first_index, details->last_index) {
2849 : :
2850 : 0 : vba = vma->vm_pgoff;
2851 : 0 : vea = vba + vma_pages(vma) - 1;
2852 : 0 : zba = details->first_index;
2853 : 0 : if (zba < vba)
2854 : : zba = vba;
2855 : 0 : zea = details->last_index;
2856 : 0 : if (zea > vea)
2857 : : zea = vea;
2858 : :
2859 : 0 : unmap_mapping_range_vma(vma,
2860 : 0 : ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2861 : 0 : ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2862 : : details);
2863 : : }
2864 : 0 : }
2865 : :
2866 : : /**
2867 : : * unmap_mapping_pages() - Unmap pages from processes.
2868 : : * @mapping: The address space containing pages to be unmapped.
2869 : : * @start: Index of first page to be unmapped.
2870 : : * @nr: Number of pages to be unmapped. 0 to unmap to end of file.
2871 : : * @even_cows: Whether to unmap even private COWed pages.
2872 : : *
2873 : : * Unmap the pages in this address space from any userspace process which
2874 : : * has them mmaped. Generally, you want to remove COWed pages as well when
2875 : : * a file is being truncated, but not when invalidating pages from the page
2876 : : * cache.
2877 : : */
2878 : 22 : void unmap_mapping_pages(struct address_space *mapping, pgoff_t start,
2879 : : pgoff_t nr, bool even_cows)
2880 : : {
2881 : 22 : struct zap_details details = { };
2882 : :
2883 [ - + ]: 22 : details.check_mapping = even_cows ? NULL : mapping;
2884 : 22 : details.first_index = start;
2885 : 22 : details.last_index = start + nr - 1;
2886 [ - + ]: 22 : if (details.last_index < details.first_index)
2887 : 0 : details.last_index = ULONG_MAX;
2888 : :
2889 : 22 : i_mmap_lock_write(mapping);
2890 [ - + ]: 22 : if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap.rb_root)))
2891 : 0 : unmap_mapping_range_tree(&mapping->i_mmap, &details);
2892 : 22 : i_mmap_unlock_write(mapping);
2893 : 22 : }
2894 : :
2895 : : /**
2896 : : * unmap_mapping_range - unmap the portion of all mmaps in the specified
2897 : : * address_space corresponding to the specified byte range in the underlying
2898 : : * file.
2899 : : *
2900 : : * @mapping: the address space containing mmaps to be unmapped.
2901 : : * @holebegin: byte in first page to unmap, relative to the start of
2902 : : * the underlying file. This will be rounded down to a PAGE_SIZE
2903 : : * boundary. Note that this is different from truncate_pagecache(), which
2904 : : * must keep the partial page. In contrast, we must get rid of
2905 : : * partial pages.
2906 : : * @holelen: size of prospective hole in bytes. This will be rounded
2907 : : * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2908 : : * end of the file.
2909 : : * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2910 : : * but 0 when invalidating pagecache, don't throw away private data.
2911 : : */
2912 : 22 : void unmap_mapping_range(struct address_space *mapping,
2913 : : loff_t const holebegin, loff_t const holelen, int even_cows)
2914 : : {
2915 : 22 : pgoff_t hba = holebegin >> PAGE_SHIFT;
2916 : 22 : pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2917 : :
2918 : : /* Check for overflow. */
2919 : 22 : if (sizeof(holelen) > sizeof(hlen)) {
2920 : : long long holeend =
2921 : : (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2922 : : if (holeend & ~(long long)ULONG_MAX)
2923 : : hlen = ULONG_MAX - hba + 1;
2924 : : }
2925 : :
2926 : 22 : unmap_mapping_pages(mapping, hba, hlen, even_cows);
2927 : 22 : }
2928 : : EXPORT_SYMBOL(unmap_mapping_range);
2929 : :
2930 : : /*
2931 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
2932 : : * but allow concurrent faults), and pte mapped but not yet locked.
2933 : : * We return with pte unmapped and unlocked.
2934 : : *
2935 : : * We return with the mmap_sem locked or unlocked in the same cases
2936 : : * as does filemap_fault().
2937 : : */
2938 : 0 : vm_fault_t do_swap_page(struct vm_fault *vmf)
2939 : : {
2940 : 0 : struct vm_area_struct *vma = vmf->vma;
2941 : 0 : struct page *page = NULL, *swapcache;
2942 : 0 : struct mem_cgroup *memcg;
2943 : 0 : swp_entry_t entry;
2944 : 0 : pte_t pte;
2945 : 0 : int locked;
2946 : 0 : int exclusive = 0;
2947 : 0 : vm_fault_t ret = 0;
2948 : :
2949 : 0 : if (!pte_unmap_same(vma->vm_mm, vmf->pmd, vmf->pte, vmf->orig_pte))
2950 : : goto out;
2951 : :
2952 [ # # ]: 0 : entry = pte_to_swp_entry(vmf->orig_pte);
2953 [ # # ]: 0 : if (unlikely(non_swap_entry(entry))) {
2954 [ # # ]: 0 : if (is_migration_entry(entry)) {
2955 : 0 : migration_entry_wait(vma->vm_mm, vmf->pmd,
2956 : : vmf->address);
2957 : 0 : } else if (is_device_private_entry(entry)) {
2958 : : vmf->page = device_private_entry_to_page(entry);
2959 : : ret = vmf->page->pgmap->ops->migrate_to_ram(vmf);
2960 : 0 : } else if (is_hwpoison_entry(entry)) {
2961 : : ret = VM_FAULT_HWPOISON;
2962 : : } else {
2963 : 0 : print_bad_pte(vma, vmf->address, vmf->orig_pte, NULL);
2964 : 0 : ret = VM_FAULT_SIGBUS;
2965 : : }
2966 : 0 : goto out;
2967 : : }
2968 : :
2969 : :
2970 [ # # ]: 0 : delayacct_set_flag(DELAYACCT_PF_SWAPIN);
2971 : 0 : page = lookup_swap_cache(entry, vma, vmf->address);
2972 : 0 : swapcache = page;
2973 : :
2974 [ # # ]: 0 : if (!page) {
2975 : 0 : struct swap_info_struct *si = swp_swap_info(entry);
2976 : :
2977 [ # # # # ]: 0 : if (si->flags & SWP_SYNCHRONOUS_IO &&
2978 : 0 : __swap_count(entry) == 1) {
2979 : : /* skip swapcache */
2980 : 0 : page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma,
2981 : : vmf->address);
2982 [ # # ]: 0 : if (page) {
2983 [ # # ]: 0 : __SetPageLocked(page);
2984 [ # # ]: 0 : __SetPageSwapBacked(page);
2985 : 0 : set_page_private(page, entry.val);
2986 : 0 : lru_cache_add_anon(page);
2987 : 0 : swap_readpage(page, true);
2988 : : }
2989 : : } else {
2990 : 0 : page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
2991 : : vmf);
2992 : 0 : swapcache = page;
2993 : : }
2994 : :
2995 [ # # ]: 0 : if (!page) {
2996 : : /*
2997 : : * Back out if somebody else faulted in this pte
2998 : : * while we released the pte lock.
2999 : : */
3000 [ # # ]: 0 : vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
3001 : : vmf->address, &vmf->ptl);
3002 [ # # ]: 0 : if (likely(pte_same(*vmf->pte, vmf->orig_pte)))
3003 : 0 : ret = VM_FAULT_OOM;
3004 [ # # ]: 0 : delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3005 : 0 : goto unlock;
3006 : : }
3007 : :
3008 : : /* Had to read the page from swap area: Major fault */
3009 : 0 : ret = VM_FAULT_MAJOR;
3010 : 0 : count_vm_event(PGMAJFAULT);
3011 : 0 : count_memcg_event_mm(vma->vm_mm, PGMAJFAULT);
3012 : : } else if (PageHWPoison(page)) {
3013 : : /*
3014 : : * hwpoisoned dirty swapcache pages are kept for killing
3015 : : * owner processes (which may be unknown at hwpoison time)
3016 : : */
3017 : : ret = VM_FAULT_HWPOISON;
3018 : : delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3019 : : goto out_release;
3020 : : }
3021 : :
3022 : 0 : locked = lock_page_or_retry(page, vma->vm_mm, vmf->flags);
3023 : :
3024 [ # # ]: 0 : delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
3025 [ # # ]: 0 : if (!locked) {
3026 : 0 : ret |= VM_FAULT_RETRY;
3027 : 0 : goto out_release;
3028 : : }
3029 : :
3030 : : /*
3031 : : * Make sure try_to_free_swap or reuse_swap_page or swapoff did not
3032 : : * release the swapcache from under us. The page pin, and pte_same
3033 : : * test below, are not enough to exclude that. Even if it is still
3034 : : * swapcache, we need to check that the page's swap has not changed.
3035 : : */
3036 [ # # # # : 0 : if (unlikely((!PageSwapCache(page) ||
# # ]
3037 [ # # ]: 0 : page_private(page) != entry.val)) && swapcache)
3038 : 0 : goto out_page;
3039 : :
3040 [ # # ]: 0 : page = ksm_might_need_to_copy(page, vma, vmf->address);
3041 [ # # ]: 0 : if (unlikely(!page)) {
3042 : 0 : ret = VM_FAULT_OOM;
3043 : 0 : page = swapcache;
3044 : 0 : goto out_page;
3045 : : }
3046 : :
3047 [ # # ]: 0 : if (mem_cgroup_try_charge_delay(page, vma->vm_mm, GFP_KERNEL,
3048 : : &memcg, false)) {
3049 : : ret = VM_FAULT_OOM;
3050 : : goto out_page;
3051 : : }
3052 : :
3053 : : /*
3054 : : * Back out if somebody else already faulted in this pte.
3055 : : */
3056 [ # # ]: 0 : vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
3057 : : &vmf->ptl);
3058 [ # # ]: 0 : if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte)))
3059 : 0 : goto out_nomap;
3060 : :
3061 [ # # ]: 0 : if (unlikely(!PageUptodate(page))) {
3062 : 0 : ret = VM_FAULT_SIGBUS;
3063 : 0 : goto out_nomap;
3064 : : }
3065 : :
3066 : : /*
3067 : : * The page isn't present yet, go ahead with the fault.
3068 : : *
3069 : : * Be careful about the sequence of operations here.
3070 : : * To get its accounting right, reuse_swap_page() must be called
3071 : : * while the page is counted on swap but not yet in mapcount i.e.
3072 : : * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
3073 : : * must be called after the swap_free(), or it will never succeed.
3074 : : */
3075 : :
3076 : 0 : inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
3077 : 0 : dec_mm_counter_fast(vma->vm_mm, MM_SWAPENTS);
3078 [ # # ]: 0 : pte = mk_pte(page, vma->vm_page_prot);
3079 [ # # # # ]: 0 : if ((vmf->flags & FAULT_FLAG_WRITE) && reuse_swap_page(page, NULL)) {
3080 [ # # ]: 0 : pte = maybe_mkwrite(pte_mkdirty(pte), vma);
3081 : 0 : vmf->flags &= ~FAULT_FLAG_WRITE;
3082 : 0 : ret |= VM_FAULT_WRITE;
3083 : 0 : exclusive = RMAP_EXCLUSIVE;
3084 : : }
3085 [ # # ]: 0 : flush_icache_page(vma, page);
3086 [ # # ]: 0 : if (pte_swp_soft_dirty(vmf->orig_pte))
3087 : : pte = pte_mksoft_dirty(pte);
3088 [ # # ]: 0 : set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte);
3089 [ # # ]: 0 : arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte);
3090 : 0 : vmf->orig_pte = pte;
3091 : :
3092 : : /* ksm created a completely new copy */
3093 [ # # ]: 0 : if (unlikely(page != swapcache && swapcache)) {
3094 : 0 : page_add_new_anon_rmap(page, vma, vmf->address, false);
3095 : 0 : mem_cgroup_commit_charge(page, memcg, false, false);
3096 : 0 : lru_cache_add_active_or_unevictable(page, vma);
3097 : : } else {
3098 : 0 : do_page_add_anon_rmap(page, vma, vmf->address, exclusive);
3099 : 0 : mem_cgroup_commit_charge(page, memcg, true, false);
3100 : 0 : activate_page(page);
3101 : : }
3102 : :
3103 : 0 : swap_free(entry);
3104 [ # # ]: 0 : if (mem_cgroup_swap_full(page) ||
3105 [ # # # # ]: 0 : (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
3106 : 0 : try_to_free_swap(page);
3107 : 0 : unlock_page(page);
3108 [ # # ]: 0 : if (page != swapcache && swapcache) {
3109 : : /*
3110 : : * Hold the lock to avoid the swap entry to be reused
3111 : : * until we take the PT lock for the pte_same() check
3112 : : * (to avoid false positives from pte_same). For
3113 : : * further safety release the lock after the swap_free
3114 : : * so that the swap count won't change under a
3115 : : * parallel locked swapcache.
3116 : : */
3117 : 0 : unlock_page(swapcache);
3118 : 0 : put_page(swapcache);
3119 : : }
3120 : :
3121 [ # # ]: 0 : if (vmf->flags & FAULT_FLAG_WRITE) {
3122 : 0 : ret |= do_wp_page(vmf);
3123 [ # # ]: 0 : if (ret & VM_FAULT_ERROR)
3124 : 0 : ret &= VM_FAULT_ERROR;
3125 : 0 : goto out;
3126 : : }
3127 : :
3128 : : /* No need to invalidate - it was non-present before */
3129 : : update_mmu_cache(vma, vmf->address, vmf->pte);
3130 : 0 : unlock:
3131 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
3132 : : out:
3133 : : return ret;
3134 : 0 : out_nomap:
3135 : 0 : mem_cgroup_cancel_charge(page, memcg, false);
3136 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
3137 : 0 : out_page:
3138 : 0 : unlock_page(page);
3139 : 0 : out_release:
3140 : 0 : put_page(page);
3141 [ # # ]: 0 : if (page != swapcache && swapcache) {
3142 : 0 : unlock_page(swapcache);
3143 : 0 : put_page(swapcache);
3144 : : }
3145 : : return ret;
3146 : : }
3147 : :
3148 : : /*
3149 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
3150 : : * but allow concurrent faults), and pte mapped but not yet locked.
3151 : : * We return with mmap_sem still held, but pte unmapped and unlocked.
3152 : : */
3153 : 152864 : static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
3154 : : {
3155 : 152864 : struct vm_area_struct *vma = vmf->vma;
3156 : 152864 : struct mem_cgroup *memcg;
3157 : 152864 : struct page *page;
3158 : 152864 : vm_fault_t ret = 0;
3159 : 152864 : pte_t entry;
3160 : :
3161 : : /* File mapping without ->vm_ops ? */
3162 [ + - ]: 152864 : if (vma->vm_flags & VM_SHARED)
3163 : : return VM_FAULT_SIGBUS;
3164 : :
3165 : : /*
3166 : : * Use pte_alloc() instead of pte_alloc_map(). We can't run
3167 : : * pte_offset_map() on pmds where a huge pmd might be created
3168 : : * from a different thread.
3169 : : *
3170 : : * pte_alloc_map() is safe to use under down_write(mmap_sem) or when
3171 : : * parallel threads are excluded by other means.
3172 : : *
3173 : : * Here we only have down_read(mmap_sem).
3174 : : */
3175 [ + + + - ]: 152864 : if (pte_alloc(vma->vm_mm, vmf->pmd))
3176 : : return VM_FAULT_OOM;
3177 : :
3178 : : /* See the comment in pte_alloc_one_map() */
3179 [ + + ]: 152864 : if (unlikely(pmd_trans_unstable(vmf->pmd)))
3180 : : return 0;
3181 : :
3182 : : /* Use the zero-page for reads */
3183 [ + + ]: 152864 : if (!(vmf->flags & FAULT_FLAG_WRITE) &&
3184 : : !mm_forbids_zeropage(vma->vm_mm)) {
3185 [ + - ]: 10153 : entry = pte_mkspecial(pfn_pte(my_zero_pfn(vmf->address),
3186 : : vma->vm_page_prot));
3187 [ + - ]: 20306 : vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd,
3188 : : vmf->address, &vmf->ptl);
3189 [ - + ]: 10153 : if (!pte_none(*vmf->pte))
3190 : 0 : goto unlock;
3191 : 10153 : ret = check_stable_address_space(vma->vm_mm);
3192 : 10153 : if (ret)
3193 : 0 : goto unlock;
3194 : : /* Deliver the page fault to userland, check inside PT lock */
3195 : 10153 : if (userfaultfd_missing(vma)) {
3196 : : pte_unmap_unlock(vmf->pte, vmf->ptl);
3197 : : return handle_userfault(vmf, VM_UFFD_MISSING);
3198 : : }
3199 : 10153 : goto setpte;
3200 : : }
3201 : :
3202 : : /* Allocate our own private page. */
3203 [ + + - + ]: 193825 : if (unlikely(anon_vma_prepare(vma)))
3204 : 0 : goto oom;
3205 : 142711 : page = alloc_zeroed_user_highpage_movable(vma, vmf->address);
3206 [ - + ]: 142711 : if (!page)
3207 : 0 : goto oom;
3208 : :
3209 : 142711 : if (mem_cgroup_try_charge_delay(page, vma->vm_mm, GFP_KERNEL, &memcg,
3210 : : false))
3211 : : goto oom_free_page;
3212 : :
3213 : : /*
3214 : : * The memory barrier inside __SetPageUptodate makes sure that
3215 : : * preceding stores to the page contents become visible before
3216 : : * the set_pte_at() write.
3217 : : */
3218 : 142711 : __SetPageUptodate(page);
3219 : :
3220 [ + - ]: 142711 : entry = mk_pte(page, vma->vm_page_prot);
3221 [ + - ]: 142711 : if (vma->vm_flags & VM_WRITE)
3222 : 142711 : entry = pte_mkwrite(pte_mkdirty(entry));
3223 : :
3224 [ + - ]: 285422 : vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
3225 : : &vmf->ptl);
3226 [ - + ]: 142711 : if (!pte_none(*vmf->pte))
3227 : 0 : goto release;
3228 : :
3229 : 142711 : ret = check_stable_address_space(vma->vm_mm);
3230 : 142711 : if (ret)
3231 : 0 : goto release;
3232 : :
3233 : : /* Deliver the page fault to userland, check inside PT lock */
3234 : 142711 : if (userfaultfd_missing(vma)) {
3235 : : pte_unmap_unlock(vmf->pte, vmf->ptl);
3236 : : mem_cgroup_cancel_charge(page, memcg, false);
3237 : : put_page(page);
3238 : : return handle_userfault(vmf, VM_UFFD_MISSING);
3239 : : }
3240 : :
3241 : 142711 : inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
3242 : 142711 : page_add_new_anon_rmap(page, vma, vmf->address, false);
3243 : 142711 : mem_cgroup_commit_charge(page, memcg, false, false);
3244 : 142711 : lru_cache_add_active_or_unevictable(page, vma);
3245 : 152864 : setpte:
3246 : 152864 : set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);
3247 : :
3248 : : /* No need to invalidate - it was non-present before */
3249 : 152864 : update_mmu_cache(vma, vmf->address, vmf->pte);
3250 : 152864 : unlock:
3251 : 152864 : pte_unmap_unlock(vmf->pte, vmf->ptl);
3252 : 152864 : return ret;
3253 : 0 : release:
3254 : 0 : mem_cgroup_cancel_charge(page, memcg, false);
3255 : 0 : put_page(page);
3256 : 0 : goto unlock;
3257 : : oom_free_page:
3258 : : put_page(page);
3259 : : oom:
3260 : : return VM_FAULT_OOM;
3261 : : }
3262 : :
3263 : : /*
3264 : : * The mmap_sem must have been held on entry, and may have been
3265 : : * released depending on flags and vma->vm_ops->fault() return value.
3266 : : * See filemap_fault() and __lock_page_retry().
3267 : : */
3268 : 92290 : static vm_fault_t __do_fault(struct vm_fault *vmf)
3269 : : {
3270 : 92290 : struct vm_area_struct *vma = vmf->vma;
3271 : 92290 : vm_fault_t ret;
3272 : :
3273 : : /*
3274 : : * Preallocate pte before we take page_lock because this might lead to
3275 : : * deadlocks for memcg reclaim which waits for pages under writeback:
3276 : : * lock_page(A)
3277 : : * SetPageWriteback(A)
3278 : : * unlock_page(A)
3279 : : * lock_page(B)
3280 : : * lock_page(B)
3281 : : * pte_alloc_pne
3282 : : * shrink_page_list
3283 : : * wait_on_page_writeback(A)
3284 : : * SetPageWriteback(B)
3285 : : * unlock_page(B)
3286 : : * # flush A, B to clear the writeback
3287 : : */
3288 [ + + + + ]: 92290 : if (pmd_none(*vmf->pmd) && !vmf->prealloc_pte) {
3289 : 18767 : vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm);
3290 [ + - ]: 18767 : if (!vmf->prealloc_pte)
3291 : : return VM_FAULT_OOM;
3292 : 18767 : smp_wmb(); /* See comment in __pte_alloc() */
3293 : : }
3294 : :
3295 : 92290 : ret = vma->vm_ops->fault(vmf);
3296 [ + + ]: 92290 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY |
3297 : : VM_FAULT_DONE_COW)))
3298 : : return ret;
3299 : :
3300 [ + + ]: 86309 : if (unlikely(PageHWPoison(vmf->page))) {
3301 : : if (ret & VM_FAULT_LOCKED)
3302 : : unlock_page(vmf->page);
3303 : : put_page(vmf->page);
3304 : : vmf->page = NULL;
3305 : : return VM_FAULT_HWPOISON;
3306 : : }
3307 : :
3308 [ + + ]: 86309 : if (unlikely(!(ret & VM_FAULT_LOCKED)))
3309 : 9075 : lock_page(vmf->page);
3310 : : else
3311 : : VM_BUG_ON_PAGE(!PageLocked(vmf->page), vmf->page);
3312 : :
3313 : : return ret;
3314 : : }
3315 : :
3316 : : /*
3317 : : * The ordering of these checks is important for pmds with _PAGE_DEVMAP set.
3318 : : * If we check pmd_trans_unstable() first we will trip the bad_pmd() check
3319 : : * inside of pmd_none_or_trans_huge_or_clear_bad(). This will end up correctly
3320 : : * returning 1 but not before it spams dmesg with the pmd_clear_bad() output.
3321 : : */
3322 : 1767723 : static int pmd_devmap_trans_unstable(pmd_t *pmd)
3323 : : {
3324 : 1767723 : return pmd_devmap(*pmd) || pmd_trans_unstable(pmd);
3325 : : }
3326 : :
3327 : 672311 : static vm_fault_t pte_alloc_one_map(struct vm_fault *vmf)
3328 : : {
3329 : 672311 : struct vm_area_struct *vma = vmf->vma;
3330 : :
3331 [ + + ]: 672311 : if (!pmd_none(*vmf->pmd))
3332 : 631231 : goto map_pte;
3333 [ + - ]: 41080 : if (vmf->prealloc_pte) {
3334 : 41080 : vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
3335 [ - + ]: 41080 : if (unlikely(!pmd_none(*vmf->pmd))) {
3336 : 0 : spin_unlock(vmf->ptl);
3337 : 0 : goto map_pte;
3338 : : }
3339 : :
3340 : 41080 : mm_inc_nr_ptes(vma->vm_mm);
3341 : 41080 : pmd_populate(vma->vm_mm, vmf->pmd, vmf->prealloc_pte);
3342 : 41080 : spin_unlock(vmf->ptl);
3343 : 41080 : vmf->prealloc_pte = NULL;
3344 [ # # # # ]: 0 : } else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) {
3345 : : return VM_FAULT_OOM;
3346 : : }
3347 : 0 : map_pte:
3348 : : /*
3349 : : * If a huge pmd materialized under us just retry later. Use
3350 : : * pmd_trans_unstable() via pmd_devmap_trans_unstable() instead of
3351 : : * pmd_trans_huge() to ensure the pmd didn't become pmd_trans_huge
3352 : : * under us and then back to pmd_none, as a result of MADV_DONTNEED
3353 : : * running immediately after a huge pmd fault in a different thread of
3354 : : * this mm, in turn leading to a misleading pmd_trans_huge() retval.
3355 : : * All we have to ensure is that it is a regular pmd that we can walk
3356 : : * with pte_offset_map() and we can do that through an atomic read in
3357 : : * C, which is what pmd_trans_unstable() provides.
3358 : : */
3359 [ + - ]: 672311 : if (pmd_devmap_trans_unstable(vmf->pmd))
3360 : : return VM_FAULT_NOPAGE;
3361 : :
3362 : : /*
3363 : : * At this point we know that our vmf->pmd points to a page of ptes
3364 : : * and it cannot become pmd_none(), pmd_devmap() or pmd_trans_huge()
3365 : : * for the duration of the fault. If a racing MADV_DONTNEED runs and
3366 : : * we zap the ptes pointed to by our vmf->pmd, the vmf->ptl will still
3367 : : * be valid and we will re-check to make sure the vmf->pte isn't
3368 : : * pte_none() under vmf->ptl protection when we return to
3369 : : * alloc_set_pte().
3370 : : */
3371 [ + - ]: 1344622 : vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address,
3372 : : &vmf->ptl);
3373 : 672311 : return 0;
3374 : : }
3375 : :
3376 : : #ifdef CONFIG_TRANSPARENT_HUGE_PAGECACHE
3377 : : static void deposit_prealloc_pte(struct vm_fault *vmf)
3378 : : {
3379 : : struct vm_area_struct *vma = vmf->vma;
3380 : :
3381 : : pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, vmf->prealloc_pte);
3382 : : /*
3383 : : * We are going to consume the prealloc table,
3384 : : * count that as nr_ptes.
3385 : : */
3386 : : mm_inc_nr_ptes(vma->vm_mm);
3387 : : vmf->prealloc_pte = NULL;
3388 : : }
3389 : :
3390 : : static vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
3391 : : {
3392 : : struct vm_area_struct *vma = vmf->vma;
3393 : : bool write = vmf->flags & FAULT_FLAG_WRITE;
3394 : : unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
3395 : : pmd_t entry;
3396 : : int i;
3397 : : vm_fault_t ret;
3398 : :
3399 : : if (!transhuge_vma_suitable(vma, haddr))
3400 : : return VM_FAULT_FALLBACK;
3401 : :
3402 : : ret = VM_FAULT_FALLBACK;
3403 : : page = compound_head(page);
3404 : :
3405 : : /*
3406 : : * Archs like ppc64 need additonal space to store information
3407 : : * related to pte entry. Use the preallocated table for that.
3408 : : */
3409 : : if (arch_needs_pgtable_deposit() && !vmf->prealloc_pte) {
3410 : : vmf->prealloc_pte = pte_alloc_one(vma->vm_mm);
3411 : : if (!vmf->prealloc_pte)
3412 : : return VM_FAULT_OOM;
3413 : : smp_wmb(); /* See comment in __pte_alloc() */
3414 : : }
3415 : :
3416 : : vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
3417 : : if (unlikely(!pmd_none(*vmf->pmd)))
3418 : : goto out;
3419 : :
3420 : : for (i = 0; i < HPAGE_PMD_NR; i++)
3421 : : flush_icache_page(vma, page + i);
3422 : :
3423 : : entry = mk_huge_pmd(page, vma->vm_page_prot);
3424 : : if (write)
3425 : : entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
3426 : :
3427 : : add_mm_counter(vma->vm_mm, mm_counter_file(page), HPAGE_PMD_NR);
3428 : : page_add_file_rmap(page, true);
3429 : : /*
3430 : : * deposit and withdraw with pmd lock held
3431 : : */
3432 : : if (arch_needs_pgtable_deposit())
3433 : : deposit_prealloc_pte(vmf);
3434 : :
3435 : : set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
3436 : :
3437 : : update_mmu_cache_pmd(vma, haddr, vmf->pmd);
3438 : :
3439 : : /* fault is handled */
3440 : : ret = 0;
3441 : : count_vm_event(THP_FILE_MAPPED);
3442 : : out:
3443 : : spin_unlock(vmf->ptl);
3444 : : return ret;
3445 : : }
3446 : : #else
3447 : : static vm_fault_t do_set_pmd(struct vm_fault *vmf, struct page *page)
3448 : : {
3449 : : BUILD_BUG();
3450 : : return 0;
3451 : : }
3452 : : #endif
3453 : :
3454 : : /**
3455 : : * alloc_set_pte - setup new PTE entry for given page and add reverse page
3456 : : * mapping. If needed, the fucntion allocates page table or use pre-allocated.
3457 : : *
3458 : : * @vmf: fault environment
3459 : : * @memcg: memcg to charge page (only for private mappings)
3460 : : * @page: page to map
3461 : : *
3462 : : * Caller must take care of unlocking vmf->ptl, if vmf->pte is non-NULL on
3463 : : * return.
3464 : : *
3465 : : * Target users are page handler itself and implementations of
3466 : : * vm_ops->map_pages.
3467 : : *
3468 : : * Return: %0 on success, %VM_FAULT_ code in case of error.
3469 : : */
3470 : 6570639 : vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
3471 : : struct page *page)
3472 : : {
3473 : 6570639 : struct vm_area_struct *vma = vmf->vma;
3474 : 6570639 : bool write = vmf->flags & FAULT_FLAG_WRITE;
3475 : 6570639 : pte_t entry;
3476 : 6570639 : vm_fault_t ret;
3477 : :
3478 [ + + ]: 6570639 : if (pmd_none(*vmf->pmd) && PageTransCompound(page) &&
3479 : : IS_ENABLED(CONFIG_TRANSPARENT_HUGE_PAGECACHE)) {
3480 : : /* THP on COW? */
3481 : : VM_BUG_ON_PAGE(memcg, page);
3482 : :
3483 : : ret = do_set_pmd(vmf, page);
3484 : : if (ret != VM_FAULT_FALLBACK)
3485 : : return ret;
3486 : : }
3487 : :
3488 [ + + ]: 6570639 : if (!vmf->pte) {
3489 : 672311 : ret = pte_alloc_one_map(vmf);
3490 [ + - ]: 672311 : if (ret)
3491 : : return ret;
3492 : : }
3493 : :
3494 : : /* Re-check under ptl */
3495 [ + + ]: 6570639 : if (unlikely(!pte_none(*vmf->pte)))
3496 : : return VM_FAULT_NOPAGE;
3497 : :
3498 [ + - ]: 6087843 : flush_icache_page(vma, page);
3499 [ + - ]: 6087843 : entry = mk_pte(page, vma->vm_page_prot);
3500 [ + + ]: 6087843 : if (write)
3501 [ + - ]: 77216 : entry = maybe_mkwrite(pte_mkdirty(entry), vma);
3502 : : /* copy-on-write page */
3503 [ + + + + ]: 6087843 : if (write && !(vma->vm_flags & VM_SHARED)) {
3504 : 75745 : inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
3505 : 75745 : page_add_new_anon_rmap(page, vma, vmf->address, false);
3506 : 75745 : mem_cgroup_commit_charge(page, memcg, false, false);
3507 : 75745 : lru_cache_add_active_or_unevictable(page, vma);
3508 : : } else {
3509 : 6012098 : inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page));
3510 : 6012098 : page_add_file_rmap(page, false);
3511 : : }
3512 : 6087843 : set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry);
3513 : :
3514 : : /* no need to invalidate: a not-present page won't be cached */
3515 : 6087843 : update_mmu_cache(vma, vmf->address, vmf->pte);
3516 : :
3517 : 6087843 : return 0;
3518 : : }
3519 : :
3520 : :
3521 : : /**
3522 : : * finish_fault - finish page fault once we have prepared the page to fault
3523 : : *
3524 : : * @vmf: structure describing the fault
3525 : : *
3526 : : * This function handles all that is needed to finish a page fault once the
3527 : : * page to fault in is prepared. It handles locking of PTEs, inserts PTE for
3528 : : * given page, adds reverse page mapping, handles memcg charges and LRU
3529 : : * addition.
3530 : : *
3531 : : * The function expects the page to be locked and on success it consumes a
3532 : : * reference of a page being mapped (for the PTE which maps it).
3533 : : *
3534 : : * Return: %0 on success, %VM_FAULT_ code in case of error.
3535 : : */
3536 : 86309 : vm_fault_t finish_fault(struct vm_fault *vmf)
3537 : : {
3538 : 86309 : struct page *page;
3539 : 86309 : vm_fault_t ret = 0;
3540 : :
3541 : : /* Did we COW the page? */
3542 [ + + ]: 86309 : if ((vmf->flags & FAULT_FLAG_WRITE) &&
3543 [ + + ]: 77216 : !(vmf->vma->vm_flags & VM_SHARED))
3544 : 75745 : page = vmf->cow_page;
3545 : : else
3546 : 10564 : page = vmf->page;
3547 : :
3548 : : /*
3549 : : * check even for read faults because we might have lost our CoWed
3550 : : * page
3551 : : */
3552 [ + + ]: 86309 : if (!(vmf->vma->vm_flags & VM_SHARED))
3553 : 84827 : ret = check_stable_address_space(vmf->vma->vm_mm);
3554 : : if (!ret)
3555 : 86309 : ret = alloc_set_pte(vmf, vmf->memcg, page);
3556 [ + - ]: 86309 : if (vmf->pte)
3557 : 86309 : pte_unmap_unlock(vmf->pte, vmf->ptl);
3558 : 86309 : return ret;
3559 : : }
3560 : :
3561 : : static unsigned long fault_around_bytes __read_mostly =
3562 : : rounddown_pow_of_two(65536);
3563 : :
3564 : : #ifdef CONFIG_DEBUG_FS
3565 : 0 : static int fault_around_bytes_get(void *data, u64 *val)
3566 : : {
3567 : 0 : *val = fault_around_bytes;
3568 : 0 : return 0;
3569 : : }
3570 : :
3571 : : /*
3572 : : * fault_around_bytes must be rounded down to the nearest page order as it's
3573 : : * what do_fault_around() expects to see.
3574 : : */
3575 : 0 : static int fault_around_bytes_set(void *data, u64 val)
3576 : : {
3577 [ # # ]: 0 : if (val / PAGE_SIZE > PTRS_PER_PTE)
3578 : : return -EINVAL;
3579 [ # # ]: 0 : if (val > PAGE_SIZE)
3580 [ # # # # : 0 : fault_around_bytes = rounddown_pow_of_two(val);
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # # #
# # # ]
3581 : : else
3582 : 0 : fault_around_bytes = PAGE_SIZE; /* rounddown_pow_of_two(0) is undefined */
3583 : : return 0;
3584 : : }
3585 : 0 : DEFINE_DEBUGFS_ATTRIBUTE(fault_around_bytes_fops,
3586 : : fault_around_bytes_get, fault_around_bytes_set, "%llu\n");
3587 : :
3588 : 11 : static int __init fault_around_debugfs(void)
3589 : : {
3590 : 11 : debugfs_create_file_unsafe("fault_around_bytes", 0644, NULL, NULL,
3591 : : &fault_around_bytes_fops);
3592 : 11 : return 0;
3593 : : }
3594 : : late_initcall(fault_around_debugfs);
3595 : : #endif
3596 : :
3597 : : /*
3598 : : * do_fault_around() tries to map few pages around the fault address. The hope
3599 : : * is that the pages will be needed soon and this will lower the number of
3600 : : * faults to handle.
3601 : : *
3602 : : * It uses vm_ops->map_pages() to map the pages, which skips the page if it's
3603 : : * not ready to be mapped: not up-to-date, locked, etc.
3604 : : *
3605 : : * This function is called with the page table lock taken. In the split ptlock
3606 : : * case the page table lock only protects only those entries which belong to
3607 : : * the page table corresponding to the fault address.
3608 : : *
3609 : : * This function doesn't cross the VMA boundaries, in order to call map_pages()
3610 : : * only once.
3611 : : *
3612 : : * fault_around_bytes defines how many bytes we'll try to map.
3613 : : * do_fault_around() expects it to be set to a power of two less than or equal
3614 : : * to PTRS_PER_PTE.
3615 : : *
3616 : : * The virtual address of the area that we map is naturally aligned to
3617 : : * fault_around_bytes rounded down to the machine page size
3618 : : * (and therefore to page order). This way it's easier to guarantee
3619 : : * that we don't cross page table boundaries.
3620 : : */
3621 : 587363 : static vm_fault_t do_fault_around(struct vm_fault *vmf)
3622 : : {
3623 : 587363 : unsigned long address = vmf->address, nr_pages, mask;
3624 : 587363 : pgoff_t start_pgoff = vmf->pgoff;
3625 : 587363 : pgoff_t end_pgoff;
3626 : 587363 : int off;
3627 : 587363 : vm_fault_t ret = 0;
3628 : :
3629 [ + + ]: 587363 : nr_pages = READ_ONCE(fault_around_bytes) >> PAGE_SHIFT;
3630 : 587363 : mask = ~(nr_pages * PAGE_SIZE - 1) & PAGE_MASK;
3631 : :
3632 : 587363 : vmf->address = max(address & mask, vmf->vma->vm_start);
3633 : 587363 : off = ((address - vmf->address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
3634 : 587363 : start_pgoff -= off;
3635 : :
3636 : : /*
3637 : : * end_pgoff is either the end of the page table, the end of
3638 : : * the vma or nr_pages from start_pgoff, depending what is nearest.
3639 : : */
3640 : 587363 : end_pgoff = start_pgoff -
3641 : 587363 : ((vmf->address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1)) +
3642 : : PTRS_PER_PTE - 1;
3643 [ + + ]: 587363 : end_pgoff = min3(end_pgoff, vma_pages(vmf->vma) + vmf->vma->vm_pgoff - 1,
3644 : : start_pgoff + nr_pages - 1);
3645 : :
3646 [ + + ]: 587363 : if (pmd_none(*vmf->pmd)) {
3647 : 22845 : vmf->prealloc_pte = pte_alloc_one(vmf->vma->vm_mm);
3648 [ - + ]: 22845 : if (!vmf->prealloc_pte)
3649 : 0 : goto out;
3650 : 22845 : smp_wmb(); /* See comment in __pte_alloc() */
3651 : : }
3652 : :
3653 : 587363 : vmf->vma->vm_ops->map_pages(vmf, start_pgoff, end_pgoff);
3654 : :
3655 : : /* Huge page is mapped? Page fault is solved */
3656 [ + + ]: 587363 : if (pmd_trans_huge(*vmf->pmd)) {
3657 : : ret = VM_FAULT_NOPAGE;
3658 : : goto out;
3659 : : }
3660 : :
3661 : : /* ->map_pages() haven't done anything useful. Cold page cache? */
3662 [ + + ]: 587363 : if (!vmf->pte)
3663 : 1361 : goto out;
3664 : :
3665 : : /* check if the page fault is solved */
3666 : 586002 : vmf->pte -= (vmf->address >> PAGE_SHIFT) - (address >> PAGE_SHIFT);
3667 [ + + ]: 586002 : if (!pte_none(*vmf->pte))
3668 : 583339 : ret = VM_FAULT_NOPAGE;
3669 : 586002 : pte_unmap_unlock(vmf->pte, vmf->ptl);
3670 : 587363 : out:
3671 : 587363 : vmf->address = address;
3672 : 587363 : vmf->pte = NULL;
3673 : 587363 : return ret;
3674 : : }
3675 : :
3676 : 597213 : static vm_fault_t do_read_fault(struct vm_fault *vmf)
3677 : : {
3678 : 597213 : struct vm_area_struct *vma = vmf->vma;
3679 : 597213 : vm_fault_t ret = 0;
3680 : :
3681 : : /*
3682 : : * Let's call ->map_pages() first and use ->fault() as fallback
3683 : : * if page by the offset is not ready to be mapped (cold cache or
3684 : : * something).
3685 : : */
3686 [ + + + - ]: 597213 : if (vma->vm_ops->map_pages && fault_around_bytes >> PAGE_SHIFT > 1) {
3687 : 587363 : ret = do_fault_around(vmf);
3688 [ + + ]: 587363 : if (ret)
3689 : : return ret;
3690 : : }
3691 : :
3692 : 13874 : ret = __do_fault(vmf);
3693 [ + + ]: 13874 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
3694 : : return ret;
3695 : :
3696 : 9093 : ret |= finish_fault(vmf);
3697 : 9093 : unlock_page(vmf->page);
3698 [ - + ]: 9093 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
3699 : 0 : put_page(vmf->page);
3700 : : return ret;
3701 : : }
3702 : :
3703 : 76945 : static vm_fault_t do_cow_fault(struct vm_fault *vmf)
3704 : : {
3705 : 76945 : struct vm_area_struct *vma = vmf->vma;
3706 : 76945 : vm_fault_t ret;
3707 : :
3708 [ + + + - ]: 125719 : if (unlikely(anon_vma_prepare(vma)))
3709 : : return VM_FAULT_OOM;
3710 : :
3711 : 76945 : vmf->cow_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vmf->address);
3712 [ + - ]: 76945 : if (!vmf->cow_page)
3713 : : return VM_FAULT_OOM;
3714 : :
3715 : 76945 : if (mem_cgroup_try_charge_delay(vmf->cow_page, vma->vm_mm, GFP_KERNEL,
3716 : : &vmf->memcg, false)) {
3717 : : put_page(vmf->cow_page);
3718 : : return VM_FAULT_OOM;
3719 : : }
3720 : :
3721 : 76945 : ret = __do_fault(vmf);
3722 [ + + ]: 76945 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
3723 : 1200 : goto uncharge_out;
3724 [ + - ]: 75745 : if (ret & VM_FAULT_DONE_COW)
3725 : : return ret;
3726 : :
3727 : 75745 : copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
3728 : 75745 : __SetPageUptodate(vmf->cow_page);
3729 : :
3730 : 75745 : ret |= finish_fault(vmf);
3731 : 75745 : unlock_page(vmf->page);
3732 : 75745 : put_page(vmf->page);
3733 [ - + ]: 75745 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
3734 : 0 : goto uncharge_out;
3735 : : return ret;
3736 : 1200 : uncharge_out:
3737 : 1200 : mem_cgroup_cancel_charge(vmf->cow_page, vmf->memcg, false);
3738 : 1200 : put_page(vmf->cow_page);
3739 : 1200 : return ret;
3740 : : }
3741 : :
3742 : 1471 : static vm_fault_t do_shared_fault(struct vm_fault *vmf)
3743 : : {
3744 : 1471 : struct vm_area_struct *vma = vmf->vma;
3745 : 1471 : vm_fault_t ret, tmp;
3746 : :
3747 : 1471 : ret = __do_fault(vmf);
3748 [ + - ]: 1471 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
3749 : : return ret;
3750 : :
3751 : : /*
3752 : : * Check if the backing address space wants to know that the page is
3753 : : * about to become writable
3754 : : */
3755 [ - + ]: 1471 : if (vma->vm_ops->page_mkwrite) {
3756 : 0 : unlock_page(vmf->page);
3757 : 0 : tmp = do_page_mkwrite(vmf);
3758 [ # # # # ]: 0 : if (unlikely(!tmp ||
3759 : : (tmp & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))) {
3760 : 0 : put_page(vmf->page);
3761 : 0 : return tmp;
3762 : : }
3763 : : }
3764 : :
3765 : 1471 : ret |= finish_fault(vmf);
3766 [ - + ]: 1471 : if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE |
3767 : : VM_FAULT_RETRY))) {
3768 : 0 : unlock_page(vmf->page);
3769 : 0 : put_page(vmf->page);
3770 : 0 : return ret;
3771 : : }
3772 : :
3773 : 1471 : ret |= fault_dirty_shared_page(vmf);
3774 : 1471 : return ret;
3775 : : }
3776 : :
3777 : : /*
3778 : : * We enter with non-exclusive mmap_sem (to exclude vma changes,
3779 : : * but allow concurrent faults).
3780 : : * The mmap_sem may have been released depending on flags and our
3781 : : * return value. See filemap_fault() and __lock_page_or_retry().
3782 : : * If mmap_sem is released, vma may become invalid (for example
3783 : : * by other thread calling munmap()).
3784 : : */
3785 : 675629 : static vm_fault_t do_fault(struct vm_fault *vmf)
3786 : : {
3787 : 675629 : struct vm_area_struct *vma = vmf->vma;
3788 : 675629 : struct mm_struct *vm_mm = vma->vm_mm;
3789 : 675629 : vm_fault_t ret;
3790 : :
3791 : : /*
3792 : : * The VMA was not fully populated on mmap() or missing VM_DONTEXPAND
3793 : : */
3794 [ - + ]: 675629 : if (!vma->vm_ops->fault) {
3795 : : /*
3796 : : * If we find a migration pmd entry or a none pmd entry, which
3797 : : * should never happen, return SIGBUS
3798 : : */
3799 [ # # # # ]: 0 : if (unlikely(!pmd_present(*vmf->pmd)))
3800 : : ret = VM_FAULT_SIGBUS;
3801 : : else {
3802 [ # # ]: 0 : vmf->pte = pte_offset_map_lock(vmf->vma->vm_mm,
3803 : : vmf->pmd,
3804 : : vmf->address,
3805 : : &vmf->ptl);
3806 : : /*
3807 : : * Make sure this is not a temporary clearing of pte
3808 : : * by holding ptl and checking again. A R/M/W update
3809 : : * of pte involves: take ptl, clearing the pte so that
3810 : : * we don't have concurrent modification by hardware
3811 : : * followed by an update.
3812 : : */
3813 [ # # ]: 0 : if (unlikely(pte_none(*vmf->pte)))
3814 : : ret = VM_FAULT_SIGBUS;
3815 : : else
3816 : 0 : ret = VM_FAULT_NOPAGE;
3817 : :
3818 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
3819 : : }
3820 [ + + ]: 675629 : } else if (!(vmf->flags & FAULT_FLAG_WRITE))
3821 : 597213 : ret = do_read_fault(vmf);
3822 [ + + ]: 78416 : else if (!(vma->vm_flags & VM_SHARED))
3823 : 76945 : ret = do_cow_fault(vmf);
3824 : : else
3825 : 1471 : ret = do_shared_fault(vmf);
3826 : :
3827 : : /* preallocated pagetable is unused: free it */
3828 [ + + ]: 675629 : if (vmf->prealloc_pte) {
3829 : 532 : pte_free(vm_mm, vmf->prealloc_pte);
3830 : 532 : vmf->prealloc_pte = NULL;
3831 : : }
3832 : 675629 : return ret;
3833 : : }
3834 : :
3835 : : static int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
3836 : : unsigned long addr, int page_nid,
3837 : : int *flags)
3838 : : {
3839 : : get_page(page);
3840 : :
3841 : : count_vm_numa_event(NUMA_HINT_FAULTS);
3842 : : if (page_nid == numa_node_id()) {
3843 : : count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
3844 : : *flags |= TNF_FAULT_LOCAL;
3845 : : }
3846 : :
3847 : : return mpol_misplaced(page, vma, addr);
3848 : : }
3849 : :
3850 : : static vm_fault_t do_numa_page(struct vm_fault *vmf)
3851 : : {
3852 : : struct vm_area_struct *vma = vmf->vma;
3853 : : struct page *page = NULL;
3854 : : int page_nid = NUMA_NO_NODE;
3855 : : int last_cpupid;
3856 : : int target_nid;
3857 : : bool migrated = false;
3858 : : pte_t pte, old_pte;
3859 : : bool was_writable = pte_savedwrite(vmf->orig_pte);
3860 : : int flags = 0;
3861 : :
3862 : : /*
3863 : : * The "pte" at this point cannot be used safely without
3864 : : * validation through pte_unmap_same(). It's of NUMA type but
3865 : : * the pfn may be screwed if the read is non atomic.
3866 : : */
3867 : : vmf->ptl = pte_lockptr(vma->vm_mm, vmf->pmd);
3868 : : spin_lock(vmf->ptl);
3869 : : if (unlikely(!pte_same(*vmf->pte, vmf->orig_pte))) {
3870 : : pte_unmap_unlock(vmf->pte, vmf->ptl);
3871 : : goto out;
3872 : : }
3873 : :
3874 : : /*
3875 : : * Make it present again, Depending on how arch implementes non
3876 : : * accessible ptes, some can allow access by kernel mode.
3877 : : */
3878 : : old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
3879 : : pte = pte_modify(old_pte, vma->vm_page_prot);
3880 : : pte = pte_mkyoung(pte);
3881 : : if (was_writable)
3882 : : pte = pte_mkwrite(pte);
3883 : : ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
3884 : : update_mmu_cache(vma, vmf->address, vmf->pte);
3885 : :
3886 : : page = vm_normal_page(vma, vmf->address, pte);
3887 : : if (!page) {
3888 : : pte_unmap_unlock(vmf->pte, vmf->ptl);
3889 : : return 0;
3890 : : }
3891 : :
3892 : : /* TODO: handle PTE-mapped THP */
3893 : : if (PageCompound(page)) {
3894 : : pte_unmap_unlock(vmf->pte, vmf->ptl);
3895 : : return 0;
3896 : : }
3897 : :
3898 : : /*
3899 : : * Avoid grouping on RO pages in general. RO pages shouldn't hurt as
3900 : : * much anyway since they can be in shared cache state. This misses
3901 : : * the case where a mapping is writable but the process never writes
3902 : : * to it but pte_write gets cleared during protection updates and
3903 : : * pte_dirty has unpredictable behaviour between PTE scan updates,
3904 : : * background writeback, dirty balancing and application behaviour.
3905 : : */
3906 : : if (!pte_write(pte))
3907 : : flags |= TNF_NO_GROUP;
3908 : :
3909 : : /*
3910 : : * Flag if the page is shared between multiple address spaces. This
3911 : : * is later used when determining whether to group tasks together
3912 : : */
3913 : : if (page_mapcount(page) > 1 && (vma->vm_flags & VM_SHARED))
3914 : : flags |= TNF_SHARED;
3915 : :
3916 : : last_cpupid = page_cpupid_last(page);
3917 : : page_nid = page_to_nid(page);
3918 : : target_nid = numa_migrate_prep(page, vma, vmf->address, page_nid,
3919 : : &flags);
3920 : : pte_unmap_unlock(vmf->pte, vmf->ptl);
3921 : : if (target_nid == NUMA_NO_NODE) {
3922 : : put_page(page);
3923 : : goto out;
3924 : : }
3925 : :
3926 : : /* Migrate to the requested node */
3927 : : migrated = migrate_misplaced_page(page, vma, target_nid);
3928 : : if (migrated) {
3929 : : page_nid = target_nid;
3930 : : flags |= TNF_MIGRATED;
3931 : : } else
3932 : : flags |= TNF_MIGRATE_FAIL;
3933 : :
3934 : : out:
3935 : : if (page_nid != NUMA_NO_NODE)
3936 : : task_numa_fault(last_cpupid, page_nid, 1, flags);
3937 : : return 0;
3938 : : }
3939 : :
3940 : : static inline vm_fault_t create_huge_pmd(struct vm_fault *vmf)
3941 : : {
3942 : : if (vma_is_anonymous(vmf->vma))
3943 : : return do_huge_pmd_anonymous_page(vmf);
3944 : : if (vmf->vma->vm_ops->huge_fault)
3945 : : return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
3946 : : return VM_FAULT_FALLBACK;
3947 : : }
3948 : :
3949 : : /* `inline' is required to avoid gcc 4.1.2 build error */
3950 : : static inline vm_fault_t wp_huge_pmd(struct vm_fault *vmf, pmd_t orig_pmd)
3951 : : {
3952 : : if (vma_is_anonymous(vmf->vma))
3953 : : return do_huge_pmd_wp_page(vmf, orig_pmd);
3954 : : if (vmf->vma->vm_ops->huge_fault)
3955 : : return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PMD);
3956 : :
3957 : : /* COW handled on pte level: split pmd */
3958 : : VM_BUG_ON_VMA(vmf->vma->vm_flags & VM_SHARED, vmf->vma);
3959 : : __split_huge_pmd(vmf->vma, vmf->pmd, vmf->address, false, NULL);
3960 : :
3961 : : return VM_FAULT_FALLBACK;
3962 : : }
3963 : :
3964 : : static inline bool vma_is_accessible(struct vm_area_struct *vma)
3965 : : {
3966 : : return vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE);
3967 : : }
3968 : :
3969 : : static vm_fault_t create_huge_pud(struct vm_fault *vmf)
3970 : : {
3971 : : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3972 : : /* No support for anonymous transparent PUD pages yet */
3973 : : if (vma_is_anonymous(vmf->vma))
3974 : : return VM_FAULT_FALLBACK;
3975 : : if (vmf->vma->vm_ops->huge_fault)
3976 : : return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD);
3977 : : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3978 : : return VM_FAULT_FALLBACK;
3979 : : }
3980 : :
3981 : : static vm_fault_t wp_huge_pud(struct vm_fault *vmf, pud_t orig_pud)
3982 : : {
3983 : : #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3984 : : /* No support for anonymous transparent PUD pages yet */
3985 : : if (vma_is_anonymous(vmf->vma))
3986 : : return VM_FAULT_FALLBACK;
3987 : : if (vmf->vma->vm_ops->huge_fault)
3988 : : return vmf->vma->vm_ops->huge_fault(vmf, PE_SIZE_PUD);
3989 : : #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3990 : : return VM_FAULT_FALLBACK;
3991 : : }
3992 : :
3993 : : /*
3994 : : * These routines also need to handle stuff like marking pages dirty
3995 : : * and/or accessed for architectures that don't do it in hardware (most
3996 : : * RISC architectures). The early dirtying is also good on the i386.
3997 : : *
3998 : : * There is also a hook called "update_mmu_cache()" that architectures
3999 : : * with external mmu caches can use to update those (ie the Sparc or
4000 : : * PowerPC hashed page tables that act as extended TLBs).
4001 : : *
4002 : : * We enter with non-exclusive mmap_sem (to exclude vma changes, but allow
4003 : : * concurrent faults).
4004 : : *
4005 : : * The mmap_sem may have been released depending on flags and our return value.
4006 : : * See filemap_fault() and __lock_page_or_retry().
4007 : : */
4008 : 1155182 : static vm_fault_t handle_pte_fault(struct vm_fault *vmf)
4009 : : {
4010 : 1155182 : pte_t entry;
4011 : :
4012 [ + + ]: 1155182 : if (unlikely(pmd_none(*vmf->pmd))) {
4013 : : /*
4014 : : * Leave __pte_alloc() until later: because vm_ops->fault may
4015 : : * want to allocate huge page, and if we expose page table
4016 : : * for an instant, it will be difficult to retract from
4017 : : * concurrent faults and from rmap lookups.
4018 : : */
4019 : 59770 : vmf->pte = NULL;
4020 : : } else {
4021 : : /* See comment in pte_alloc_one_map() */
4022 [ + - ]: 1095412 : if (pmd_devmap_trans_unstable(vmf->pmd))
4023 : : return 0;
4024 : : /*
4025 : : * A regular pmd is established and it can't morph into a huge
4026 : : * pmd from under us anymore at this point because we hold the
4027 : : * mmap_sem read mode and khugepaged takes it in write mode.
4028 : : * So now it's safe to run pte_offset_map().
4029 : : */
4030 [ + - ]: 1095412 : vmf->pte = pte_offset_map(vmf->pmd, vmf->address);
4031 : 1095412 : vmf->orig_pte = *vmf->pte;
4032 : :
4033 : : /*
4034 : : * some architectures can have larger ptes than wordsize,
4035 : : * e.g.ppc44x-defconfig has CONFIG_PTE_64BIT=y and
4036 : : * CONFIG_32BIT=y, so READ_ONCE cannot guarantee atomic
4037 : : * accesses. The code below just needs a consistent view
4038 : : * for the ifs and we later double check anyway with the
4039 : : * ptl lock held. So here a barrier will do.
4040 : : */
4041 : 1095412 : barrier();
4042 [ + + ]: 1095412 : if (pte_none(vmf->orig_pte)) {
4043 : 768723 : pte_unmap(vmf->pte);
4044 : 768723 : vmf->pte = NULL;
4045 : : }
4046 : : }
4047 : :
4048 [ + + ]: 1155182 : if (!vmf->pte) {
4049 [ + + ]: 828493 : if (vma_is_anonymous(vmf->vma))
4050 : 152864 : return do_anonymous_page(vmf);
4051 : : else
4052 : 675629 : return do_fault(vmf);
4053 : : }
4054 : :
4055 [ - + ]: 326689 : if (!pte_present(vmf->orig_pte))
4056 : 0 : return do_swap_page(vmf);
4057 : :
4058 [ + - ]: 326689 : if (pte_protnone(vmf->orig_pte) && vma_is_accessible(vmf->vma))
4059 : : return do_numa_page(vmf);
4060 : :
4061 [ + - ]: 326689 : vmf->ptl = pte_lockptr(vmf->vma->vm_mm, vmf->pmd);
4062 : 326689 : spin_lock(vmf->ptl);
4063 : 326689 : entry = vmf->orig_pte;
4064 [ - + ]: 326689 : if (unlikely(!pte_same(*vmf->pte, entry)))
4065 : 0 : goto unlock;
4066 [ + - ]: 326689 : if (vmf->flags & FAULT_FLAG_WRITE) {
4067 [ + - ]: 326689 : if (!pte_write(entry))
4068 : 326689 : return do_wp_page(vmf);
4069 : 0 : entry = pte_mkdirty(entry);
4070 : : }
4071 : 0 : entry = pte_mkyoung(entry);
4072 : 0 : if (ptep_set_access_flags(vmf->vma, vmf->address, vmf->pte, entry,
4073 : 0 : vmf->flags & FAULT_FLAG_WRITE)) {
4074 : : update_mmu_cache(vmf->vma, vmf->address, vmf->pte);
4075 : : } else {
4076 : : /*
4077 : : * This is needed only for protection faults but the arch code
4078 : : * is not yet telling us if this is a protection fault or not.
4079 : : * This still avoids useless tlb flushes for .text page faults
4080 : : * with threads.
4081 : : */
4082 : 0 : if (vmf->flags & FAULT_FLAG_WRITE)
4083 : 0 : flush_tlb_fix_spurious_fault(vmf->vma, vmf->address);
4084 : : }
4085 : 0 : unlock:
4086 : 0 : pte_unmap_unlock(vmf->pte, vmf->ptl);
4087 : 0 : return 0;
4088 : : }
4089 : :
4090 : : /*
4091 : : * By the time we get here, we already hold the mm semaphore
4092 : : *
4093 : : * The mmap_sem may have been released depending on flags and our
4094 : : * return value. See filemap_fault() and __lock_page_or_retry().
4095 : : */
4096 : 1155182 : static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma,
4097 : : unsigned long address, unsigned int flags)
4098 : : {
4099 : 3465546 : struct vm_fault vmf = {
4100 : : .vma = vma,
4101 : 1155182 : .address = address & PAGE_MASK,
4102 : : .flags = flags,
4103 : 1155182 : .pgoff = linear_page_index(vma, address),
4104 [ + + ]: 1155182 : .gfp_mask = __get_fault_gfp_mask(vma),
4105 : : };
4106 : 1155182 : unsigned int dirty = flags & FAULT_FLAG_WRITE;
4107 : 1155182 : struct mm_struct *mm = vma->vm_mm;
4108 : 1155182 : pgd_t *pgd;
4109 : 1155182 : p4d_t *p4d;
4110 : 1155182 : vm_fault_t ret;
4111 : :
4112 : 1155182 : pgd = pgd_offset(mm, address);
4113 : 1155182 : p4d = p4d_alloc(mm, pgd, address);
4114 [ + - ]: 1155182 : if (!p4d)
4115 : : return VM_FAULT_OOM;
4116 : :
4117 : 1155182 : vmf.pud = pud_alloc(mm, p4d, address);
4118 [ + - ]: 1155182 : if (!vmf.pud)
4119 : : return VM_FAULT_OOM;
4120 : 1155182 : retry_pud:
4121 : 1155182 : if (pud_none(*vmf.pud) && __transparent_hugepage_enabled(vma)) {
4122 : : ret = create_huge_pud(&vmf);
4123 : : if (!(ret & VM_FAULT_FALLBACK))
4124 : : return ret;
4125 : : } else {
4126 : 1155182 : pud_t orig_pud = *vmf.pud;
4127 : :
4128 : 1155182 : barrier();
4129 : 1155182 : if (pud_trans_huge(orig_pud) || pud_devmap(orig_pud)) {
4130 : :
4131 : : /* NUMA case for anonymous PUDs would go here */
4132 : :
4133 : : if (dirty && !pud_write(orig_pud)) {
4134 : : ret = wp_huge_pud(&vmf, orig_pud);
4135 : : if (!(ret & VM_FAULT_FALLBACK))
4136 : : return ret;
4137 : : } else {
4138 : : huge_pud_set_accessed(&vmf, orig_pud);
4139 : : return 0;
4140 : : }
4141 : : }
4142 : : }
4143 : :
4144 : 1155182 : vmf.pmd = pmd_alloc(mm, vmf.pud, address);
4145 [ + - ]: 1155182 : if (!vmf.pmd)
4146 : : return VM_FAULT_OOM;
4147 : :
4148 : : /* Huge pud page fault raced with pmd_alloc? */
4149 : 1155182 : if (pud_trans_unstable(vmf.pud))
4150 : : goto retry_pud;
4151 : :
4152 : 1155182 : if (pmd_none(*vmf.pmd) && __transparent_hugepage_enabled(vma)) {
4153 : : ret = create_huge_pmd(&vmf);
4154 : : if (!(ret & VM_FAULT_FALLBACK))
4155 : : return ret;
4156 : : } else {
4157 : 1155182 : pmd_t orig_pmd = *vmf.pmd;
4158 : :
4159 : 1155182 : barrier();
4160 : 1155182 : if (unlikely(is_swap_pmd(orig_pmd))) {
4161 : : VM_BUG_ON(thp_migration_supported() &&
4162 : : !is_pmd_migration_entry(orig_pmd));
4163 : : if (is_pmd_migration_entry(orig_pmd))
4164 : : pmd_migration_entry_wait(mm, vmf.pmd);
4165 : : return 0;
4166 : : }
4167 : 1155182 : if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
4168 : : if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
4169 : : return do_huge_pmd_numa_page(&vmf, orig_pmd);
4170 : :
4171 : : if (dirty && !pmd_write(orig_pmd)) {
4172 : : ret = wp_huge_pmd(&vmf, orig_pmd);
4173 : : if (!(ret & VM_FAULT_FALLBACK))
4174 : : return ret;
4175 : : } else {
4176 : : huge_pmd_set_accessed(&vmf, orig_pmd);
4177 : : return 0;
4178 : : }
4179 : : }
4180 : : }
4181 : :
4182 : 1155182 : return handle_pte_fault(&vmf);
4183 : : }
4184 : :
4185 : : /*
4186 : : * By the time we get here, we already hold the mm semaphore
4187 : : *
4188 : : * The mmap_sem may have been released depending on flags and our
4189 : : * return value. See filemap_fault() and __lock_page_or_retry().
4190 : : */
4191 : 1155182 : vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
4192 : : unsigned int flags)
4193 : : {
4194 : 1155182 : vm_fault_t ret;
4195 : :
4196 : 1155182 : __set_current_state(TASK_RUNNING);
4197 : :
4198 : 1155182 : count_vm_event(PGFAULT);
4199 : 1155182 : count_memcg_event_mm(vma->vm_mm, PGFAULT);
4200 : :
4201 : : /* do counter updates before entering really critical section. */
4202 : 1155182 : check_sync_rss_stat(current);
4203 : :
4204 [ + - ]: 1155182 : if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
4205 : 1155182 : flags & FAULT_FLAG_INSTRUCTION,
4206 : 1155182 : flags & FAULT_FLAG_REMOTE))
4207 : : return VM_FAULT_SIGSEGV;
4208 : :
4209 : : /*
4210 : : * Enable the memcg OOM handling for faults triggered in user
4211 : : * space. Kernel faults are handled more gracefully.
4212 : : */
4213 : 1155182 : if (flags & FAULT_FLAG_USER)
4214 : : mem_cgroup_enter_user_fault();
4215 : :
4216 [ - + ]: 1155182 : if (unlikely(is_vm_hugetlb_page(vma)))
4217 : 0 : ret = hugetlb_fault(vma->vm_mm, vma, address, flags);
4218 : : else
4219 : 1155182 : ret = __handle_mm_fault(vma, address, flags);
4220 : :
4221 [ + + ]: 1155182 : if (flags & FAULT_FLAG_USER) {
4222 : 1088055 : mem_cgroup_exit_user_fault();
4223 : : /*
4224 : : * The task may have entered a memcg OOM situation but
4225 : : * if the allocation error was handled gracefully (no
4226 : : * VM_FAULT_OOM), there is no need to kill anything.
4227 : : * Just clean up the OOM state peacefully.
4228 : : */
4229 : 1088055 : if (task_in_memcg_oom(current) && !(ret & VM_FAULT_OOM))
4230 : : mem_cgroup_oom_synchronize(false);
4231 : : }
4232 : :
4233 : : return ret;
4234 : : }
4235 : : EXPORT_SYMBOL_GPL(handle_mm_fault);
4236 : :
4237 : : #ifndef __PAGETABLE_P4D_FOLDED
4238 : : /*
4239 : : * Allocate p4d page table.
4240 : : * We've already handled the fast-path in-line.
4241 : : */
4242 : 0 : int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
4243 : : {
4244 [ # # ]: 0 : p4d_t *new = p4d_alloc_one(mm, address);
4245 [ # # ]: 0 : if (!new)
4246 : : return -ENOMEM;
4247 : :
4248 : 0 : smp_wmb(); /* See comment in __pte_alloc */
4249 : :
4250 : 0 : spin_lock(&mm->page_table_lock);
4251 [ # # ]: 0 : if (pgd_present(*pgd)) /* Another has populated it */
4252 : 0 : p4d_free(mm, new);
4253 : : else
4254 : 0 : pgd_populate(mm, pgd, new);
4255 : 0 : spin_unlock(&mm->page_table_lock);
4256 : 0 : return 0;
4257 : : }
4258 : : #endif /* __PAGETABLE_P4D_FOLDED */
4259 : :
4260 : : #ifndef __PAGETABLE_PUD_FOLDED
4261 : : /*
4262 : : * Allocate page upper directory.
4263 : : * We've already handled the fast-path in-line.
4264 : : */
4265 : 45394 : int __pud_alloc(struct mm_struct *mm, p4d_t *p4d, unsigned long address)
4266 : : {
4267 [ + + ]: 45394 : pud_t *new = pud_alloc_one(mm, address);
4268 [ + - ]: 45394 : if (!new)
4269 : : return -ENOMEM;
4270 : :
4271 : 45394 : smp_wmb(); /* See comment in __pte_alloc */
4272 : :
4273 : 45394 : spin_lock(&mm->page_table_lock);
4274 : : #ifndef __ARCH_HAS_5LEVEL_HACK
4275 [ + - ]: 45394 : if (!p4d_present(*p4d)) {
4276 : 45394 : mm_inc_nr_puds(mm);
4277 : 45394 : p4d_populate(mm, p4d, new);
4278 : : } else /* Another has populated it */
4279 : 0 : pud_free(mm, new);
4280 : : #else
4281 : : if (!pgd_present(*p4d)) {
4282 : : mm_inc_nr_puds(mm);
4283 : : pgd_populate(mm, p4d, new);
4284 : : } else /* Another has populated it */
4285 : : pud_free(mm, new);
4286 : : #endif /* __ARCH_HAS_5LEVEL_HACK */
4287 : 45394 : spin_unlock(&mm->page_table_lock);
4288 : 45394 : return 0;
4289 : : }
4290 : : #endif /* __PAGETABLE_PUD_FOLDED */
4291 : :
4292 : : #ifndef __PAGETABLE_PMD_FOLDED
4293 : : /*
4294 : : * Allocate page middle directory.
4295 : : * We've already handled the fast-path in-line.
4296 : : */
4297 : 62652 : int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
4298 : : {
4299 : 62652 : spinlock_t *ptl;
4300 : 62652 : pmd_t *new = pmd_alloc_one(mm, address);
4301 [ + - ]: 62652 : if (!new)
4302 : : return -ENOMEM;
4303 : :
4304 : 62652 : smp_wmb(); /* See comment in __pte_alloc */
4305 : :
4306 : 62652 : ptl = pud_lock(mm, pud);
4307 [ + - + - ]: 125304 : if (!pud_present(*pud)) {
4308 : 62652 : mm_inc_nr_pmds(mm);
4309 [ + - ]: 62652 : pud_populate(mm, pud, new);
4310 : : } else /* Another has populated it */
4311 : 0 : pmd_free(mm, new);
4312 : 62652 : spin_unlock(ptl);
4313 : 62652 : return 0;
4314 : : }
4315 : : #endif /* __PAGETABLE_PMD_FOLDED */
4316 : :
4317 : 0 : static int __follow_pte_pmd(struct mm_struct *mm, unsigned long address,
4318 : : struct mmu_notifier_range *range,
4319 : : pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
4320 : : {
4321 : 0 : pgd_t *pgd;
4322 : 0 : p4d_t *p4d;
4323 : 0 : pud_t *pud;
4324 : 0 : pmd_t *pmd;
4325 : 0 : pte_t *ptep;
4326 : :
4327 : 0 : pgd = pgd_offset(mm, address);
4328 [ # # # # ]: 0 : if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
4329 : 0 : goto out;
4330 : :
4331 : 0 : p4d = p4d_offset(pgd, address);
4332 [ # # # # ]: 0 : if (p4d_none(*p4d) || unlikely(p4d_bad(*p4d)))
4333 : 0 : goto out;
4334 : :
4335 [ # # ]: 0 : pud = pud_offset(p4d, address);
4336 [ # # # # ]: 0 : if (pud_none(*pud) || unlikely(pud_bad(*pud)))
4337 : 0 : goto out;
4338 : :
4339 : 0 : pmd = pmd_offset(pud, address);
4340 : 0 : VM_BUG_ON(pmd_trans_huge(*pmd));
4341 : :
4342 [ # # ]: 0 : if (pmd_huge(*pmd)) {
4343 [ # # ]: 0 : if (!pmdpp)
4344 : 0 : goto out;
4345 : :
4346 [ # # ]: 0 : if (range) {
4347 : 0 : mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0,
4348 : : NULL, mm, address & PMD_MASK,
4349 : 0 : (address & PMD_MASK) + PMD_SIZE);
4350 : 0 : mmu_notifier_invalidate_range_start(range);
4351 : : }
4352 : 0 : *ptlp = pmd_lock(mm, pmd);
4353 [ # # ]: 0 : if (pmd_huge(*pmd)) {
4354 : 0 : *pmdpp = pmd;
4355 : 0 : return 0;
4356 : : }
4357 : 0 : spin_unlock(*ptlp);
4358 [ # # ]: 0 : if (range)
4359 : 0 : mmu_notifier_invalidate_range_end(range);
4360 : : }
4361 : :
4362 [ # # # # ]: 0 : if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
4363 : 0 : goto out;
4364 : :
4365 [ # # ]: 0 : if (range) {
4366 : 0 : mmu_notifier_range_init(range, MMU_NOTIFY_CLEAR, 0, NULL, mm,
4367 : : address & PAGE_MASK,
4368 : 0 : (address & PAGE_MASK) + PAGE_SIZE);
4369 : 0 : mmu_notifier_invalidate_range_start(range);
4370 : : }
4371 [ # # ]: 0 : ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
4372 [ # # ]: 0 : if (!pte_present(*ptep))
4373 : 0 : goto unlock;
4374 : 0 : *ptepp = ptep;
4375 : 0 : return 0;
4376 : : unlock:
4377 : 0 : pte_unmap_unlock(ptep, *ptlp);
4378 [ # # ]: 0 : if (range)
4379 : 0 : mmu_notifier_invalidate_range_end(range);
4380 : 0 : out:
4381 : : return -EINVAL;
4382 : : }
4383 : :
4384 : 0 : static inline int follow_pte(struct mm_struct *mm, unsigned long address,
4385 : : pte_t **ptepp, spinlock_t **ptlp)
4386 : : {
4387 : 0 : int res;
4388 : :
4389 : : /* (void) is needed to make gcc happy */
4390 : 0 : (void) __cond_lock(*ptlp,
4391 : : !(res = __follow_pte_pmd(mm, address, NULL,
4392 : : ptepp, NULL, ptlp)));
4393 : 0 : return res;
4394 : : }
4395 : :
4396 : 0 : int follow_pte_pmd(struct mm_struct *mm, unsigned long address,
4397 : : struct mmu_notifier_range *range,
4398 : : pte_t **ptepp, pmd_t **pmdpp, spinlock_t **ptlp)
4399 : : {
4400 : 0 : int res;
4401 : :
4402 : : /* (void) is needed to make gcc happy */
4403 : 0 : (void) __cond_lock(*ptlp,
4404 : : !(res = __follow_pte_pmd(mm, address, range,
4405 : : ptepp, pmdpp, ptlp)));
4406 : 0 : return res;
4407 : : }
4408 : : EXPORT_SYMBOL(follow_pte_pmd);
4409 : :
4410 : : /**
4411 : : * follow_pfn - look up PFN at a user virtual address
4412 : : * @vma: memory mapping
4413 : : * @address: user virtual address
4414 : : * @pfn: location to store found PFN
4415 : : *
4416 : : * Only IO mappings and raw PFN mappings are allowed.
4417 : : *
4418 : : * Return: zero and the pfn at @pfn on success, -ve otherwise.
4419 : : */
4420 : 0 : int follow_pfn(struct vm_area_struct *vma, unsigned long address,
4421 : : unsigned long *pfn)
4422 : : {
4423 : 0 : int ret = -EINVAL;
4424 : 0 : spinlock_t *ptl;
4425 : 0 : pte_t *ptep;
4426 : :
4427 [ # # ]: 0 : if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
4428 : : return ret;
4429 : :
4430 : 0 : ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
4431 [ # # ]: 0 : if (ret)
4432 : : return ret;
4433 [ # # ]: 0 : *pfn = pte_pfn(*ptep);
4434 : 0 : pte_unmap_unlock(ptep, ptl);
4435 : 0 : return 0;
4436 : : }
4437 : : EXPORT_SYMBOL(follow_pfn);
4438 : :
4439 : : #ifdef CONFIG_HAVE_IOREMAP_PROT
4440 : 0 : int follow_phys(struct vm_area_struct *vma,
4441 : : unsigned long address, unsigned int flags,
4442 : : unsigned long *prot, resource_size_t *phys)
4443 : : {
4444 : 0 : int ret = -EINVAL;
4445 : 0 : pte_t *ptep, pte;
4446 : 0 : spinlock_t *ptl;
4447 : :
4448 [ # # ]: 0 : if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
4449 : 0 : goto out;
4450 : :
4451 [ # # ]: 0 : if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
4452 : 0 : goto out;
4453 : 0 : pte = *ptep;
4454 : :
4455 [ # # # # ]: 0 : if ((flags & FOLL_WRITE) && !pte_write(pte))
4456 : 0 : goto unlock;
4457 : :
4458 [ # # ]: 0 : *prot = pgprot_val(pte_pgprot(pte));
4459 [ # # ]: 0 : *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
4460 : :
4461 : 0 : ret = 0;
4462 : 0 : unlock:
4463 : 0 : pte_unmap_unlock(ptep, ptl);
4464 : 0 : out:
4465 : 0 : return ret;
4466 : : }
4467 : :
4468 : 0 : int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
4469 : : void *buf, int len, int write)
4470 : : {
4471 : 0 : resource_size_t phys_addr;
4472 : 0 : unsigned long prot = 0;
4473 : 0 : void __iomem *maddr;
4474 : 0 : int offset = addr & (PAGE_SIZE-1);
4475 : :
4476 [ # # ]: 0 : if (follow_phys(vma, addr, write, &prot, &phys_addr))
4477 : : return -EINVAL;
4478 : :
4479 : 0 : maddr = ioremap_prot(phys_addr, PAGE_ALIGN(len + offset), prot);
4480 [ # # ]: 0 : if (!maddr)
4481 : : return -ENOMEM;
4482 : :
4483 [ # # ]: 0 : if (write)
4484 : 0 : memcpy_toio(maddr + offset, buf, len);
4485 : : else
4486 : 0 : memcpy_fromio(buf, maddr + offset, len);
4487 : 0 : iounmap(maddr);
4488 : :
4489 : 0 : return len;
4490 : : }
4491 : : EXPORT_SYMBOL_GPL(generic_access_phys);
4492 : : #endif
4493 : :
4494 : : /*
4495 : : * Access another process' address space as given in mm. If non-NULL, use the
4496 : : * given task for page fault accounting.
4497 : : */
4498 : 748 : int __access_remote_vm(struct task_struct *tsk, struct mm_struct *mm,
4499 : : unsigned long addr, void *buf, int len, unsigned int gup_flags)
4500 : : {
4501 : 748 : struct vm_area_struct *vma;
4502 : 748 : void *old_buf = buf;
4503 : 748 : int write = gup_flags & FOLL_WRITE;
4504 : :
4505 [ + - ]: 748 : if (down_read_killable(&mm->mmap_sem))
4506 : : return 0;
4507 : :
4508 : : /* ignore errors, just check how much was successfully transferred */
4509 [ + + ]: 1496 : while (len) {
4510 : 748 : int bytes, ret, offset;
4511 : 748 : void *maddr;
4512 : 748 : struct page *page = NULL;
4513 : :
4514 : 748 : ret = get_user_pages_remote(tsk, mm, addr, 1,
4515 : : gup_flags, &page, &vma, NULL);
4516 [ - + ]: 748 : if (ret <= 0) {
4517 : : #ifndef CONFIG_HAVE_IOREMAP_PROT
4518 : : break;
4519 : : #else
4520 : : /*
4521 : : * Check if this is a VM_IO | VM_PFNMAP VMA, which
4522 : : * we can access using slightly different code.
4523 : : */
4524 : 0 : vma = find_vma(mm, addr);
4525 [ # # # # ]: 0 : if (!vma || vma->vm_start > addr)
4526 : : break;
4527 [ # # # # ]: 0 : if (vma->vm_ops && vma->vm_ops->access)
4528 : 0 : ret = vma->vm_ops->access(vma, addr, buf,
4529 : : len, write);
4530 [ # # ]: 0 : if (ret <= 0)
4531 : : break;
4532 : : bytes = ret;
4533 : : #endif
4534 : : } else {
4535 : 748 : bytes = len;
4536 : 748 : offset = addr & (PAGE_SIZE-1);
4537 [ - + ]: 748 : if (bytes > PAGE_SIZE-offset)
4538 : 0 : bytes = PAGE_SIZE-offset;
4539 : :
4540 : 748 : maddr = kmap(page);
4541 [ - + ]: 748 : if (write) {
4542 : 0 : copy_to_user_page(vma, page, addr,
4543 : : maddr + offset, buf, bytes);
4544 : 0 : set_page_dirty_lock(page);
4545 : : } else {
4546 : 748 : copy_from_user_page(vma, page, addr,
4547 : : buf, maddr + offset, bytes);
4548 : : }
4549 : 748 : kunmap(page);
4550 : 748 : put_page(page);
4551 : : }
4552 : 748 : len -= bytes;
4553 : 748 : buf += bytes;
4554 : 748 : addr += bytes;
4555 : : }
4556 : 748 : up_read(&mm->mmap_sem);
4557 : :
4558 : 748 : return buf - old_buf;
4559 : : }
4560 : :
4561 : : /**
4562 : : * access_remote_vm - access another process' address space
4563 : : * @mm: the mm_struct of the target address space
4564 : : * @addr: start address to access
4565 : : * @buf: source or destination buffer
4566 : : * @len: number of bytes to transfer
4567 : : * @gup_flags: flags modifying lookup behaviour
4568 : : *
4569 : : * The caller must hold a reference on @mm.
4570 : : *
4571 : : * Return: number of bytes copied from source to destination.
4572 : : */
4573 : 748 : int access_remote_vm(struct mm_struct *mm, unsigned long addr,
4574 : : void *buf, int len, unsigned int gup_flags)
4575 : : {
4576 : 748 : return __access_remote_vm(NULL, mm, addr, buf, len, gup_flags);
4577 : : }
4578 : :
4579 : : /*
4580 : : * Access another process' address space.
4581 : : * Source/target buffer must be kernel space,
4582 : : * Do not walk the page table directly, use get_user_pages
4583 : : */
4584 : 0 : int access_process_vm(struct task_struct *tsk, unsigned long addr,
4585 : : void *buf, int len, unsigned int gup_flags)
4586 : : {
4587 : 0 : struct mm_struct *mm;
4588 : 0 : int ret;
4589 : :
4590 : 0 : mm = get_task_mm(tsk);
4591 [ # # ]: 0 : if (!mm)
4592 : : return 0;
4593 : :
4594 : 0 : ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
4595 : :
4596 : 0 : mmput(mm);
4597 : :
4598 : 0 : return ret;
4599 : : }
4600 : : EXPORT_SYMBOL_GPL(access_process_vm);
4601 : :
4602 : : /*
4603 : : * Print the name of a VMA.
4604 : : */
4605 : 0 : void print_vma_addr(char *prefix, unsigned long ip)
4606 : : {
4607 : 0 : struct mm_struct *mm = current->mm;
4608 : 0 : struct vm_area_struct *vma;
4609 : :
4610 : : /*
4611 : : * we might be running from an atomic context so we cannot sleep
4612 : : */
4613 [ # # ]: 0 : if (!down_read_trylock(&mm->mmap_sem))
4614 : : return;
4615 : :
4616 : 0 : vma = find_vma(mm, ip);
4617 [ # # # # ]: 0 : if (vma && vma->vm_file) {
4618 : 0 : struct file *f = vma->vm_file;
4619 : 0 : char *buf = (char *)__get_free_page(GFP_NOWAIT);
4620 [ # # ]: 0 : if (buf) {
4621 : 0 : char *p;
4622 : :
4623 : 0 : p = file_path(f, buf, PAGE_SIZE);
4624 [ # # ]: 0 : if (IS_ERR(p))
4625 : 0 : p = "?";
4626 : 0 : printk("%s%s[%lx+%lx]", prefix, kbasename(p),
4627 : : vma->vm_start,
4628 [ # # ]: 0 : vma->vm_end - vma->vm_start);
4629 : 0 : free_page((unsigned long)buf);
4630 : : }
4631 : : }
4632 : 0 : up_read(&mm->mmap_sem);
4633 : : }
4634 : :
4635 : : #if defined(CONFIG_PROVE_LOCKING) || defined(CONFIG_DEBUG_ATOMIC_SLEEP)
4636 : : void __might_fault(const char *file, int line)
4637 : : {
4638 : : /*
4639 : : * Some code (nfs/sunrpc) uses socket ops on kernel memory while
4640 : : * holding the mmap_sem, this is safe because kernel memory doesn't
4641 : : * get paged out, therefore we'll never actually fault, and the
4642 : : * below annotations will generate false positives.
4643 : : */
4644 : : if (uaccess_kernel())
4645 : : return;
4646 : : if (pagefault_disabled())
4647 : : return;
4648 : : __might_sleep(file, line, 0);
4649 : : #if defined(CONFIG_DEBUG_ATOMIC_SLEEP)
4650 : : if (current->mm)
4651 : : might_lock_read(¤t->mm->mmap_sem);
4652 : : #endif
4653 : : }
4654 : : EXPORT_SYMBOL(__might_fault);
4655 : : #endif
4656 : :
4657 : : #if defined(CONFIG_TRANSPARENT_HUGEPAGE) || defined(CONFIG_HUGETLBFS)
4658 : : /*
4659 : : * Process all subpages of the specified huge page with the specified
4660 : : * operation. The target subpage will be processed last to keep its
4661 : : * cache lines hot.
4662 : : */
4663 : 0 : static inline void process_huge_page(
4664 : : unsigned long addr_hint, unsigned int pages_per_huge_page,
4665 : : void (*process_subpage)(unsigned long addr, int idx, void *arg),
4666 : : void *arg)
4667 : : {
4668 : 0 : int i, n, base, l;
4669 : 0 : unsigned long addr = addr_hint &
4670 : 0 : ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
4671 : :
4672 : : /* Process target subpage last to keep its cache lines hot */
4673 : 0 : might_sleep();
4674 : 0 : n = (addr_hint - addr) / PAGE_SIZE;
4675 [ # # ]: 0 : if (2 * n <= pages_per_huge_page) {
4676 : : /* If target subpage in first half of huge page */
4677 : 0 : base = 0;
4678 : 0 : l = n;
4679 : : /* Process subpages at the end of huge page */
4680 [ # # ]: 0 : for (i = pages_per_huge_page - 1; i >= 2 * n; i--) {
4681 : 0 : cond_resched();
4682 : 0 : process_subpage(addr + i * PAGE_SIZE, i, arg);
4683 : : }
4684 : : } else {
4685 : : /* If target subpage in second half of huge page */
4686 : 0 : base = pages_per_huge_page - 2 * (pages_per_huge_page - n);
4687 : 0 : l = pages_per_huge_page - n;
4688 : : /* Process subpages at the begin of huge page */
4689 [ # # ]: 0 : for (i = 0; i < base; i++) {
4690 : 0 : cond_resched();
4691 : 0 : process_subpage(addr + i * PAGE_SIZE, i, arg);
4692 : : }
4693 : : }
4694 : : /*
4695 : : * Process remaining subpages in left-right-left-right pattern
4696 : : * towards the target subpage
4697 : : */
4698 [ # # ]: 0 : for (i = 0; i < l; i++) {
4699 : 0 : int left_idx = base + i;
4700 : 0 : int right_idx = base + 2 * l - 1 - i;
4701 : :
4702 : 0 : cond_resched();
4703 : 0 : process_subpage(addr + left_idx * PAGE_SIZE, left_idx, arg);
4704 : 0 : cond_resched();
4705 : 0 : process_subpage(addr + right_idx * PAGE_SIZE, right_idx, arg);
4706 : : }
4707 : 0 : }
4708 : :
4709 : : static void clear_gigantic_page(struct page *page,
4710 : : unsigned long addr,
4711 : : unsigned int pages_per_huge_page)
4712 : : {
4713 : : int i;
4714 : : struct page *p = page;
4715 : :
4716 : : might_sleep();
4717 : : for (i = 0; i < pages_per_huge_page;
4718 : : i++, p = mem_map_next(p, page, i)) {
4719 : : cond_resched();
4720 : : clear_user_highpage(p, addr + i * PAGE_SIZE);
4721 : : }
4722 : : }
4723 : :
4724 : 0 : static void clear_subpage(unsigned long addr, int idx, void *arg)
4725 : : {
4726 : 0 : struct page *page = arg;
4727 : :
4728 : 0 : clear_user_highpage(page + idx, addr);
4729 : 0 : }
4730 : :
4731 : 0 : void clear_huge_page(struct page *page,
4732 : : unsigned long addr_hint, unsigned int pages_per_huge_page)
4733 : : {
4734 : 0 : unsigned long addr = addr_hint &
4735 : : ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
4736 : :
4737 [ # # ]: 0 : if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4738 : 0 : clear_gigantic_page(page, addr, pages_per_huge_page);
4739 : 0 : return;
4740 : : }
4741 : :
4742 : 0 : process_huge_page(addr_hint, pages_per_huge_page, clear_subpage, page);
4743 : : }
4744 : :
4745 : : static void copy_user_gigantic_page(struct page *dst, struct page *src,
4746 : : unsigned long addr,
4747 : : struct vm_area_struct *vma,
4748 : : unsigned int pages_per_huge_page)
4749 : : {
4750 : : int i;
4751 : : struct page *dst_base = dst;
4752 : : struct page *src_base = src;
4753 : :
4754 : : for (i = 0; i < pages_per_huge_page; ) {
4755 : : cond_resched();
4756 : : copy_user_highpage(dst, src, addr + i*PAGE_SIZE, vma);
4757 : :
4758 : : i++;
4759 : : dst = mem_map_next(dst, dst_base, i);
4760 : : src = mem_map_next(src, src_base, i);
4761 : : }
4762 : : }
4763 : :
4764 : : struct copy_subpage_arg {
4765 : : struct page *dst;
4766 : : struct page *src;
4767 : : struct vm_area_struct *vma;
4768 : : };
4769 : :
4770 : 0 : static void copy_subpage(unsigned long addr, int idx, void *arg)
4771 : : {
4772 : 0 : struct copy_subpage_arg *copy_arg = arg;
4773 : :
4774 : 0 : copy_user_highpage(copy_arg->dst + idx, copy_arg->src + idx,
4775 : : addr, copy_arg->vma);
4776 : 0 : }
4777 : :
4778 : 0 : void copy_user_huge_page(struct page *dst, struct page *src,
4779 : : unsigned long addr_hint, struct vm_area_struct *vma,
4780 : : unsigned int pages_per_huge_page)
4781 : : {
4782 : 0 : unsigned long addr = addr_hint &
4783 : : ~(((unsigned long)pages_per_huge_page << PAGE_SHIFT) - 1);
4784 : 0 : struct copy_subpage_arg arg = {
4785 : : .dst = dst,
4786 : : .src = src,
4787 : : .vma = vma,
4788 : : };
4789 : :
4790 [ # # ]: 0 : if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
4791 : 0 : copy_user_gigantic_page(dst, src, addr, vma,
4792 : : pages_per_huge_page);
4793 : 0 : return;
4794 : : }
4795 : :
4796 : 0 : process_huge_page(addr_hint, pages_per_huge_page, copy_subpage, &arg);
4797 : : }
4798 : :
4799 : 0 : long copy_huge_page_from_user(struct page *dst_page,
4800 : : const void __user *usr_src,
4801 : : unsigned int pages_per_huge_page,
4802 : : bool allow_pagefault)
4803 : : {
4804 : 0 : void *src = (void *)usr_src;
4805 : 0 : void *page_kaddr;
4806 : 0 : unsigned long i, rc = 0;
4807 : 0 : unsigned long ret_val = pages_per_huge_page * PAGE_SIZE;
4808 : :
4809 [ # # ]: 0 : for (i = 0; i < pages_per_huge_page; i++) {
4810 [ # # ]: 0 : if (allow_pagefault)
4811 : 0 : page_kaddr = kmap(dst_page + i);
4812 : : else
4813 : 0 : page_kaddr = kmap_atomic(dst_page + i);
4814 : 0 : rc = copy_from_user(page_kaddr,
4815 [ # # ]: 0 : (const void __user *)(src + i * PAGE_SIZE),
4816 : : PAGE_SIZE);
4817 [ # # ]: 0 : if (allow_pagefault)
4818 : : kunmap(dst_page + i);
4819 : : else
4820 : 0 : kunmap_atomic(page_kaddr);
4821 : :
4822 : 0 : ret_val -= (PAGE_SIZE - rc);
4823 [ # # ]: 0 : if (rc)
4824 : : break;
4825 : :
4826 : 0 : cond_resched();
4827 : : }
4828 : 0 : return ret_val;
4829 : : }
4830 : : #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
4831 : :
4832 : : #if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS
4833 : :
4834 : : static struct kmem_cache *page_ptl_cachep;
4835 : :
4836 : : void __init ptlock_cache_init(void)
4837 : : {
4838 : : page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,
4839 : : SLAB_PANIC, NULL);
4840 : : }
4841 : :
4842 : : bool ptlock_alloc(struct page *page)
4843 : : {
4844 : : spinlock_t *ptl;
4845 : :
4846 : : ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
4847 : : if (!ptl)
4848 : : return false;
4849 : : page->ptl = ptl;
4850 : : return true;
4851 : : }
4852 : :
4853 : : void ptlock_free(struct page *page)
4854 : : {
4855 : : kmem_cache_free(page_ptl_cachep, page->ptl);
4856 : : }
4857 : : #endif
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