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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * linux/mm/memory.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * demand-loading started 01.12.91 - seems it is high on the list of | |
9 | * things wanted, and it should be easy to implement. - Linus | |
10 | */ | |
11 | ||
12 | /* | |
13 | * Ok, demand-loading was easy, shared pages a little bit tricker. Shared | |
14 | * pages started 02.12.91, seems to work. - Linus. | |
15 | * | |
16 | * Tested sharing by executing about 30 /bin/sh: under the old kernel it | |
17 | * would have taken more than the 6M I have free, but it worked well as | |
18 | * far as I could see. | |
19 | * | |
20 | * Also corrected some "invalidate()"s - I wasn't doing enough of them. | |
21 | */ | |
22 | ||
23 | /* | |
24 | * Real VM (paging to/from disk) started 18.12.91. Much more work and | |
25 | * thought has to go into this. Oh, well.. | |
26 | * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. | |
27 | * Found it. Everything seems to work now. | |
28 | * 20.12.91 - Ok, making the swap-device changeable like the root. | |
29 | */ | |
30 | ||
31 | /* | |
32 | * 05.04.94 - Multi-page memory management added for v1.1. | |
33 | * Idea by Alex Bligh (alex@cconcepts.co.uk) | |
34 | * | |
35 | * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG | |
36 | * (Gerhard.Wichert@pdb.siemens.de) | |
37 | * | |
38 | * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) | |
39 | */ | |
40 | ||
41 | #include <linux/kernel_stat.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/hugetlb.h> | |
44 | #include <linux/mman.h> | |
45 | #include <linux/swap.h> | |
46 | #include <linux/highmem.h> | |
47 | #include <linux/pagemap.h> | |
48 | #include <linux/rmap.h> | |
49 | #include <linux/module.h> | |
0ff92245 | 50 | #include <linux/delayacct.h> |
1da177e4 | 51 | #include <linux/init.h> |
edc79b2a | 52 | #include <linux/writeback.h> |
8a9f3ccd | 53 | #include <linux/memcontrol.h> |
cddb8a5c | 54 | #include <linux/mmu_notifier.h> |
3dc14741 HD |
55 | #include <linux/kallsyms.h> |
56 | #include <linux/swapops.h> | |
57 | #include <linux/elf.h> | |
1da177e4 | 58 | |
6952b61d | 59 | #include <asm/io.h> |
1da177e4 LT |
60 | #include <asm/pgalloc.h> |
61 | #include <asm/uaccess.h> | |
62 | #include <asm/tlb.h> | |
63 | #include <asm/tlbflush.h> | |
64 | #include <asm/pgtable.h> | |
65 | ||
42b77728 JB |
66 | #include "internal.h" |
67 | ||
d41dee36 | 68 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
69 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
70 | unsigned long max_mapnr; | |
71 | struct page *mem_map; | |
72 | ||
73 | EXPORT_SYMBOL(max_mapnr); | |
74 | EXPORT_SYMBOL(mem_map); | |
75 | #endif | |
76 | ||
77 | unsigned long num_physpages; | |
78 | /* | |
79 | * A number of key systems in x86 including ioremap() rely on the assumption | |
80 | * that high_memory defines the upper bound on direct map memory, then end | |
81 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and | |
82 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL | |
83 | * and ZONE_HIGHMEM. | |
84 | */ | |
85 | void * high_memory; | |
1da177e4 LT |
86 | |
87 | EXPORT_SYMBOL(num_physpages); | |
88 | EXPORT_SYMBOL(high_memory); | |
1da177e4 | 89 | |
32a93233 IM |
90 | /* |
91 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
92 | * | |
93 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
94 | * as ancient (libc5 based) binaries can segfault. ) | |
95 | */ | |
96 | int randomize_va_space __read_mostly = | |
97 | #ifdef CONFIG_COMPAT_BRK | |
98 | 1; | |
99 | #else | |
100 | 2; | |
101 | #endif | |
a62eaf15 AK |
102 | |
103 | static int __init disable_randmaps(char *s) | |
104 | { | |
105 | randomize_va_space = 0; | |
9b41046c | 106 | return 1; |
a62eaf15 AK |
107 | } |
108 | __setup("norandmaps", disable_randmaps); | |
109 | ||
110 | ||
1da177e4 LT |
111 | /* |
112 | * If a p?d_bad entry is found while walking page tables, report | |
113 | * the error, before resetting entry to p?d_none. Usually (but | |
114 | * very seldom) called out from the p?d_none_or_clear_bad macros. | |
115 | */ | |
116 | ||
117 | void pgd_clear_bad(pgd_t *pgd) | |
118 | { | |
119 | pgd_ERROR(*pgd); | |
120 | pgd_clear(pgd); | |
121 | } | |
122 | ||
123 | void pud_clear_bad(pud_t *pud) | |
124 | { | |
125 | pud_ERROR(*pud); | |
126 | pud_clear(pud); | |
127 | } | |
128 | ||
129 | void pmd_clear_bad(pmd_t *pmd) | |
130 | { | |
131 | pmd_ERROR(*pmd); | |
132 | pmd_clear(pmd); | |
133 | } | |
134 | ||
135 | /* | |
136 | * Note: this doesn't free the actual pages themselves. That | |
137 | * has been handled earlier when unmapping all the memory regions. | |
138 | */ | |
9e1b32ca BH |
139 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd, |
140 | unsigned long addr) | |
1da177e4 | 141 | { |
2f569afd | 142 | pgtable_t token = pmd_pgtable(*pmd); |
e0da382c | 143 | pmd_clear(pmd); |
9e1b32ca | 144 | pte_free_tlb(tlb, token, addr); |
e0da382c | 145 | tlb->mm->nr_ptes--; |
1da177e4 LT |
146 | } |
147 | ||
e0da382c HD |
148 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
149 | unsigned long addr, unsigned long end, | |
150 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
151 | { |
152 | pmd_t *pmd; | |
153 | unsigned long next; | |
e0da382c | 154 | unsigned long start; |
1da177e4 | 155 | |
e0da382c | 156 | start = addr; |
1da177e4 | 157 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
158 | do { |
159 | next = pmd_addr_end(addr, end); | |
160 | if (pmd_none_or_clear_bad(pmd)) | |
161 | continue; | |
9e1b32ca | 162 | free_pte_range(tlb, pmd, addr); |
1da177e4 LT |
163 | } while (pmd++, addr = next, addr != end); |
164 | ||
e0da382c HD |
165 | start &= PUD_MASK; |
166 | if (start < floor) | |
167 | return; | |
168 | if (ceiling) { | |
169 | ceiling &= PUD_MASK; | |
170 | if (!ceiling) | |
171 | return; | |
1da177e4 | 172 | } |
e0da382c HD |
173 | if (end - 1 > ceiling - 1) |
174 | return; | |
175 | ||
176 | pmd = pmd_offset(pud, start); | |
177 | pud_clear(pud); | |
9e1b32ca | 178 | pmd_free_tlb(tlb, pmd, start); |
1da177e4 LT |
179 | } |
180 | ||
e0da382c HD |
181 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
182 | unsigned long addr, unsigned long end, | |
183 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
184 | { |
185 | pud_t *pud; | |
186 | unsigned long next; | |
e0da382c | 187 | unsigned long start; |
1da177e4 | 188 | |
e0da382c | 189 | start = addr; |
1da177e4 | 190 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
191 | do { |
192 | next = pud_addr_end(addr, end); | |
193 | if (pud_none_or_clear_bad(pud)) | |
194 | continue; | |
e0da382c | 195 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
196 | } while (pud++, addr = next, addr != end); |
197 | ||
e0da382c HD |
198 | start &= PGDIR_MASK; |
199 | if (start < floor) | |
200 | return; | |
201 | if (ceiling) { | |
202 | ceiling &= PGDIR_MASK; | |
203 | if (!ceiling) | |
204 | return; | |
1da177e4 | 205 | } |
e0da382c HD |
206 | if (end - 1 > ceiling - 1) |
207 | return; | |
208 | ||
209 | pud = pud_offset(pgd, start); | |
210 | pgd_clear(pgd); | |
9e1b32ca | 211 | pud_free_tlb(tlb, pud, start); |
1da177e4 LT |
212 | } |
213 | ||
214 | /* | |
e0da382c HD |
215 | * This function frees user-level page tables of a process. |
216 | * | |
1da177e4 LT |
217 | * Must be called with pagetable lock held. |
218 | */ | |
42b77728 | 219 | void free_pgd_range(struct mmu_gather *tlb, |
e0da382c HD |
220 | unsigned long addr, unsigned long end, |
221 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
222 | { |
223 | pgd_t *pgd; | |
224 | unsigned long next; | |
e0da382c HD |
225 | unsigned long start; |
226 | ||
227 | /* | |
228 | * The next few lines have given us lots of grief... | |
229 | * | |
230 | * Why are we testing PMD* at this top level? Because often | |
231 | * there will be no work to do at all, and we'd prefer not to | |
232 | * go all the way down to the bottom just to discover that. | |
233 | * | |
234 | * Why all these "- 1"s? Because 0 represents both the bottom | |
235 | * of the address space and the top of it (using -1 for the | |
236 | * top wouldn't help much: the masks would do the wrong thing). | |
237 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
238 | * the address space, but end 0 and ceiling 0 refer to the top | |
239 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
240 | * that end 0 case should be mythical). | |
241 | * | |
242 | * Wherever addr is brought up or ceiling brought down, we must | |
243 | * be careful to reject "the opposite 0" before it confuses the | |
244 | * subsequent tests. But what about where end is brought down | |
245 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
246 | * | |
247 | * Whereas we round start (addr) and ceiling down, by different | |
248 | * masks at different levels, in order to test whether a table | |
249 | * now has no other vmas using it, so can be freed, we don't | |
250 | * bother to round floor or end up - the tests don't need that. | |
251 | */ | |
1da177e4 | 252 | |
e0da382c HD |
253 | addr &= PMD_MASK; |
254 | if (addr < floor) { | |
255 | addr += PMD_SIZE; | |
256 | if (!addr) | |
257 | return; | |
258 | } | |
259 | if (ceiling) { | |
260 | ceiling &= PMD_MASK; | |
261 | if (!ceiling) | |
262 | return; | |
263 | } | |
264 | if (end - 1 > ceiling - 1) | |
265 | end -= PMD_SIZE; | |
266 | if (addr > end - 1) | |
267 | return; | |
268 | ||
269 | start = addr; | |
42b77728 | 270 | pgd = pgd_offset(tlb->mm, addr); |
1da177e4 LT |
271 | do { |
272 | next = pgd_addr_end(addr, end); | |
273 | if (pgd_none_or_clear_bad(pgd)) | |
274 | continue; | |
42b77728 | 275 | free_pud_range(tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 276 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
277 | } |
278 | ||
42b77728 | 279 | void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3bf5ee95 | 280 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
281 | { |
282 | while (vma) { | |
283 | struct vm_area_struct *next = vma->vm_next; | |
284 | unsigned long addr = vma->vm_start; | |
285 | ||
8f4f8c16 HD |
286 | /* |
287 | * Hide vma from rmap and vmtruncate before freeing pgtables | |
288 | */ | |
289 | anon_vma_unlink(vma); | |
290 | unlink_file_vma(vma); | |
291 | ||
9da61aef | 292 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 293 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 294 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
295 | } else { |
296 | /* | |
297 | * Optimization: gather nearby vmas into one call down | |
298 | */ | |
299 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 300 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
301 | vma = next; |
302 | next = vma->vm_next; | |
8f4f8c16 HD |
303 | anon_vma_unlink(vma); |
304 | unlink_file_vma(vma); | |
3bf5ee95 HD |
305 | } |
306 | free_pgd_range(tlb, addr, vma->vm_end, | |
307 | floor, next? next->vm_start: ceiling); | |
308 | } | |
e0da382c HD |
309 | vma = next; |
310 | } | |
1da177e4 LT |
311 | } |
312 | ||
1bb3630e | 313 | int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
1da177e4 | 314 | { |
2f569afd | 315 | pgtable_t new = pte_alloc_one(mm, address); |
1bb3630e HD |
316 | if (!new) |
317 | return -ENOMEM; | |
318 | ||
362a61ad NP |
319 | /* |
320 | * Ensure all pte setup (eg. pte page lock and page clearing) are | |
321 | * visible before the pte is made visible to other CPUs by being | |
322 | * put into page tables. | |
323 | * | |
324 | * The other side of the story is the pointer chasing in the page | |
325 | * table walking code (when walking the page table without locking; | |
326 | * ie. most of the time). Fortunately, these data accesses consist | |
327 | * of a chain of data-dependent loads, meaning most CPUs (alpha | |
328 | * being the notable exception) will already guarantee loads are | |
329 | * seen in-order. See the alpha page table accessors for the | |
330 | * smp_read_barrier_depends() barriers in page table walking code. | |
331 | */ | |
332 | smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ | |
333 | ||
c74df32c | 334 | spin_lock(&mm->page_table_lock); |
2f569afd | 335 | if (!pmd_present(*pmd)) { /* Has another populated it ? */ |
1da177e4 | 336 | mm->nr_ptes++; |
1da177e4 | 337 | pmd_populate(mm, pmd, new); |
2f569afd | 338 | new = NULL; |
1da177e4 | 339 | } |
c74df32c | 340 | spin_unlock(&mm->page_table_lock); |
2f569afd MS |
341 | if (new) |
342 | pte_free(mm, new); | |
1bb3630e | 343 | return 0; |
1da177e4 LT |
344 | } |
345 | ||
1bb3630e | 346 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 347 | { |
1bb3630e HD |
348 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
349 | if (!new) | |
350 | return -ENOMEM; | |
351 | ||
362a61ad NP |
352 | smp_wmb(); /* See comment in __pte_alloc */ |
353 | ||
1bb3630e | 354 | spin_lock(&init_mm.page_table_lock); |
2f569afd | 355 | if (!pmd_present(*pmd)) { /* Has another populated it ? */ |
1bb3630e | 356 | pmd_populate_kernel(&init_mm, pmd, new); |
2f569afd MS |
357 | new = NULL; |
358 | } | |
1bb3630e | 359 | spin_unlock(&init_mm.page_table_lock); |
2f569afd MS |
360 | if (new) |
361 | pte_free_kernel(&init_mm, new); | |
1bb3630e | 362 | return 0; |
1da177e4 LT |
363 | } |
364 | ||
ae859762 HD |
365 | static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) |
366 | { | |
367 | if (file_rss) | |
368 | add_mm_counter(mm, file_rss, file_rss); | |
369 | if (anon_rss) | |
370 | add_mm_counter(mm, anon_rss, anon_rss); | |
371 | } | |
372 | ||
b5810039 | 373 | /* |
6aab341e LT |
374 | * This function is called to print an error when a bad pte |
375 | * is found. For example, we might have a PFN-mapped pte in | |
376 | * a region that doesn't allow it. | |
b5810039 NP |
377 | * |
378 | * The calling function must still handle the error. | |
379 | */ | |
3dc14741 HD |
380 | static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr, |
381 | pte_t pte, struct page *page) | |
b5810039 | 382 | { |
3dc14741 HD |
383 | pgd_t *pgd = pgd_offset(vma->vm_mm, addr); |
384 | pud_t *pud = pud_offset(pgd, addr); | |
385 | pmd_t *pmd = pmd_offset(pud, addr); | |
386 | struct address_space *mapping; | |
387 | pgoff_t index; | |
d936cf9b HD |
388 | static unsigned long resume; |
389 | static unsigned long nr_shown; | |
390 | static unsigned long nr_unshown; | |
391 | ||
392 | /* | |
393 | * Allow a burst of 60 reports, then keep quiet for that minute; | |
394 | * or allow a steady drip of one report per second. | |
395 | */ | |
396 | if (nr_shown == 60) { | |
397 | if (time_before(jiffies, resume)) { | |
398 | nr_unshown++; | |
399 | return; | |
400 | } | |
401 | if (nr_unshown) { | |
1e9e6365 HD |
402 | printk(KERN_ALERT |
403 | "BUG: Bad page map: %lu messages suppressed\n", | |
d936cf9b HD |
404 | nr_unshown); |
405 | nr_unshown = 0; | |
406 | } | |
407 | nr_shown = 0; | |
408 | } | |
409 | if (nr_shown++ == 0) | |
410 | resume = jiffies + 60 * HZ; | |
3dc14741 HD |
411 | |
412 | mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL; | |
413 | index = linear_page_index(vma, addr); | |
414 | ||
1e9e6365 HD |
415 | printk(KERN_ALERT |
416 | "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n", | |
3dc14741 HD |
417 | current->comm, |
418 | (long long)pte_val(pte), (long long)pmd_val(*pmd)); | |
419 | if (page) { | |
1e9e6365 | 420 | printk(KERN_ALERT |
3dc14741 HD |
421 | "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n", |
422 | page, (void *)page->flags, page_count(page), | |
423 | page_mapcount(page), page->mapping, page->index); | |
424 | } | |
1e9e6365 | 425 | printk(KERN_ALERT |
3dc14741 HD |
426 | "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n", |
427 | (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index); | |
428 | /* | |
429 | * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y | |
430 | */ | |
431 | if (vma->vm_ops) | |
1e9e6365 | 432 | print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n", |
3dc14741 HD |
433 | (unsigned long)vma->vm_ops->fault); |
434 | if (vma->vm_file && vma->vm_file->f_op) | |
1e9e6365 | 435 | print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n", |
3dc14741 | 436 | (unsigned long)vma->vm_file->f_op->mmap); |
b5810039 | 437 | dump_stack(); |
3dc14741 | 438 | add_taint(TAINT_BAD_PAGE); |
b5810039 NP |
439 | } |
440 | ||
67121172 LT |
441 | static inline int is_cow_mapping(unsigned int flags) |
442 | { | |
443 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
444 | } | |
445 | ||
ee498ed7 | 446 | /* |
7e675137 | 447 | * vm_normal_page -- This function gets the "struct page" associated with a pte. |
6aab341e | 448 | * |
7e675137 NP |
449 | * "Special" mappings do not wish to be associated with a "struct page" (either |
450 | * it doesn't exist, or it exists but they don't want to touch it). In this | |
451 | * case, NULL is returned here. "Normal" mappings do have a struct page. | |
b379d790 | 452 | * |
7e675137 NP |
453 | * There are 2 broad cases. Firstly, an architecture may define a pte_special() |
454 | * pte bit, in which case this function is trivial. Secondly, an architecture | |
455 | * may not have a spare pte bit, which requires a more complicated scheme, | |
456 | * described below. | |
457 | * | |
458 | * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a | |
459 | * special mapping (even if there are underlying and valid "struct pages"). | |
460 | * COWed pages of a VM_PFNMAP are always normal. | |
6aab341e | 461 | * |
b379d790 JH |
462 | * The way we recognize COWed pages within VM_PFNMAP mappings is through the |
463 | * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit | |
7e675137 NP |
464 | * set, and the vm_pgoff will point to the first PFN mapped: thus every special |
465 | * mapping will always honor the rule | |
6aab341e LT |
466 | * |
467 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
468 | * | |
7e675137 NP |
469 | * And for normal mappings this is false. |
470 | * | |
471 | * This restricts such mappings to be a linear translation from virtual address | |
472 | * to pfn. To get around this restriction, we allow arbitrary mappings so long | |
473 | * as the vma is not a COW mapping; in that case, we know that all ptes are | |
474 | * special (because none can have been COWed). | |
b379d790 | 475 | * |
b379d790 | 476 | * |
7e675137 | 477 | * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. |
b379d790 JH |
478 | * |
479 | * VM_MIXEDMAP mappings can likewise contain memory with or without "struct | |
480 | * page" backing, however the difference is that _all_ pages with a struct | |
481 | * page (that is, those where pfn_valid is true) are refcounted and considered | |
482 | * normal pages by the VM. The disadvantage is that pages are refcounted | |
483 | * (which can be slower and simply not an option for some PFNMAP users). The | |
484 | * advantage is that we don't have to follow the strict linearity rule of | |
485 | * PFNMAP mappings in order to support COWable mappings. | |
486 | * | |
ee498ed7 | 487 | */ |
7e675137 NP |
488 | #ifdef __HAVE_ARCH_PTE_SPECIAL |
489 | # define HAVE_PTE_SPECIAL 1 | |
490 | #else | |
491 | # define HAVE_PTE_SPECIAL 0 | |
492 | #endif | |
493 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, | |
494 | pte_t pte) | |
ee498ed7 | 495 | { |
22b31eec | 496 | unsigned long pfn = pte_pfn(pte); |
7e675137 NP |
497 | |
498 | if (HAVE_PTE_SPECIAL) { | |
22b31eec HD |
499 | if (likely(!pte_special(pte))) |
500 | goto check_pfn; | |
501 | if (!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))) | |
502 | print_bad_pte(vma, addr, pte, NULL); | |
7e675137 NP |
503 | return NULL; |
504 | } | |
505 | ||
506 | /* !HAVE_PTE_SPECIAL case follows: */ | |
507 | ||
b379d790 JH |
508 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { |
509 | if (vma->vm_flags & VM_MIXEDMAP) { | |
510 | if (!pfn_valid(pfn)) | |
511 | return NULL; | |
512 | goto out; | |
513 | } else { | |
7e675137 NP |
514 | unsigned long off; |
515 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
b379d790 JH |
516 | if (pfn == vma->vm_pgoff + off) |
517 | return NULL; | |
518 | if (!is_cow_mapping(vma->vm_flags)) | |
519 | return NULL; | |
520 | } | |
6aab341e LT |
521 | } |
522 | ||
22b31eec HD |
523 | check_pfn: |
524 | if (unlikely(pfn > highest_memmap_pfn)) { | |
525 | print_bad_pte(vma, addr, pte, NULL); | |
526 | return NULL; | |
527 | } | |
6aab341e LT |
528 | |
529 | /* | |
7e675137 | 530 | * NOTE! We still have PageReserved() pages in the page tables. |
7e675137 | 531 | * eg. VDSO mappings can cause them to exist. |
6aab341e | 532 | */ |
b379d790 | 533 | out: |
6aab341e | 534 | return pfn_to_page(pfn); |
ee498ed7 HD |
535 | } |
536 | ||
1da177e4 LT |
537 | /* |
538 | * copy one vm_area from one task to the other. Assumes the page tables | |
539 | * already present in the new task to be cleared in the whole range | |
540 | * covered by this vma. | |
1da177e4 LT |
541 | */ |
542 | ||
8c103762 | 543 | static inline void |
1da177e4 | 544 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 545 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 546 | unsigned long addr, int *rss) |
1da177e4 | 547 | { |
b5810039 | 548 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
549 | pte_t pte = *src_pte; |
550 | struct page *page; | |
1da177e4 LT |
551 | |
552 | /* pte contains position in swap or file, so copy. */ | |
553 | if (unlikely(!pte_present(pte))) { | |
554 | if (!pte_file(pte)) { | |
0697212a CL |
555 | swp_entry_t entry = pte_to_swp_entry(pte); |
556 | ||
557 | swap_duplicate(entry); | |
1da177e4 LT |
558 | /* make sure dst_mm is on swapoff's mmlist. */ |
559 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
560 | spin_lock(&mmlist_lock); | |
f412ac08 HD |
561 | if (list_empty(&dst_mm->mmlist)) |
562 | list_add(&dst_mm->mmlist, | |
563 | &src_mm->mmlist); | |
1da177e4 LT |
564 | spin_unlock(&mmlist_lock); |
565 | } | |
0697212a CL |
566 | if (is_write_migration_entry(entry) && |
567 | is_cow_mapping(vm_flags)) { | |
568 | /* | |
569 | * COW mappings require pages in both parent | |
570 | * and child to be set to read. | |
571 | */ | |
572 | make_migration_entry_read(&entry); | |
573 | pte = swp_entry_to_pte(entry); | |
574 | set_pte_at(src_mm, addr, src_pte, pte); | |
575 | } | |
1da177e4 | 576 | } |
ae859762 | 577 | goto out_set_pte; |
1da177e4 LT |
578 | } |
579 | ||
1da177e4 LT |
580 | /* |
581 | * If it's a COW mapping, write protect it both | |
582 | * in the parent and the child | |
583 | */ | |
67121172 | 584 | if (is_cow_mapping(vm_flags)) { |
1da177e4 | 585 | ptep_set_wrprotect(src_mm, addr, src_pte); |
3dc90795 | 586 | pte = pte_wrprotect(pte); |
1da177e4 LT |
587 | } |
588 | ||
589 | /* | |
590 | * If it's a shared mapping, mark it clean in | |
591 | * the child | |
592 | */ | |
593 | if (vm_flags & VM_SHARED) | |
594 | pte = pte_mkclean(pte); | |
595 | pte = pte_mkold(pte); | |
6aab341e LT |
596 | |
597 | page = vm_normal_page(vma, addr, pte); | |
598 | if (page) { | |
599 | get_page(page); | |
c97a9e10 | 600 | page_dup_rmap(page, vma, addr); |
6aab341e LT |
601 | rss[!!PageAnon(page)]++; |
602 | } | |
ae859762 HD |
603 | |
604 | out_set_pte: | |
605 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
1da177e4 LT |
606 | } |
607 | ||
608 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
609 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, | |
610 | unsigned long addr, unsigned long end) | |
611 | { | |
612 | pte_t *src_pte, *dst_pte; | |
c74df32c | 613 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 614 | int progress = 0; |
8c103762 | 615 | int rss[2]; |
1da177e4 LT |
616 | |
617 | again: | |
ae859762 | 618 | rss[1] = rss[0] = 0; |
c74df32c | 619 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
620 | if (!dst_pte) |
621 | return -ENOMEM; | |
622 | src_pte = pte_offset_map_nested(src_pmd, addr); | |
4c21e2f2 | 623 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 624 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
6606c3e0 | 625 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 626 | |
1da177e4 LT |
627 | do { |
628 | /* | |
629 | * We are holding two locks at this point - either of them | |
630 | * could generate latencies in another task on another CPU. | |
631 | */ | |
e040f218 HD |
632 | if (progress >= 32) { |
633 | progress = 0; | |
634 | if (need_resched() || | |
95c354fe | 635 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
636 | break; |
637 | } | |
1da177e4 LT |
638 | if (pte_none(*src_pte)) { |
639 | progress++; | |
640 | continue; | |
641 | } | |
8c103762 | 642 | copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); |
1da177e4 LT |
643 | progress += 8; |
644 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 645 | |
6606c3e0 | 646 | arch_leave_lazy_mmu_mode(); |
c74df32c | 647 | spin_unlock(src_ptl); |
1da177e4 | 648 | pte_unmap_nested(src_pte - 1); |
ae859762 | 649 | add_mm_rss(dst_mm, rss[0], rss[1]); |
c74df32c HD |
650 | pte_unmap_unlock(dst_pte - 1, dst_ptl); |
651 | cond_resched(); | |
1da177e4 LT |
652 | if (addr != end) |
653 | goto again; | |
654 | return 0; | |
655 | } | |
656 | ||
657 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
658 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
659 | unsigned long addr, unsigned long end) | |
660 | { | |
661 | pmd_t *src_pmd, *dst_pmd; | |
662 | unsigned long next; | |
663 | ||
664 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
665 | if (!dst_pmd) | |
666 | return -ENOMEM; | |
667 | src_pmd = pmd_offset(src_pud, addr); | |
668 | do { | |
669 | next = pmd_addr_end(addr, end); | |
670 | if (pmd_none_or_clear_bad(src_pmd)) | |
671 | continue; | |
672 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
673 | vma, addr, next)) | |
674 | return -ENOMEM; | |
675 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
676 | return 0; | |
677 | } | |
678 | ||
679 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
680 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
681 | unsigned long addr, unsigned long end) | |
682 | { | |
683 | pud_t *src_pud, *dst_pud; | |
684 | unsigned long next; | |
685 | ||
686 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
687 | if (!dst_pud) | |
688 | return -ENOMEM; | |
689 | src_pud = pud_offset(src_pgd, addr); | |
690 | do { | |
691 | next = pud_addr_end(addr, end); | |
692 | if (pud_none_or_clear_bad(src_pud)) | |
693 | continue; | |
694 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
695 | vma, addr, next)) | |
696 | return -ENOMEM; | |
697 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
698 | return 0; | |
699 | } | |
700 | ||
701 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
702 | struct vm_area_struct *vma) | |
703 | { | |
704 | pgd_t *src_pgd, *dst_pgd; | |
705 | unsigned long next; | |
706 | unsigned long addr = vma->vm_start; | |
707 | unsigned long end = vma->vm_end; | |
cddb8a5c | 708 | int ret; |
1da177e4 | 709 | |
d992895b NP |
710 | /* |
711 | * Don't copy ptes where a page fault will fill them correctly. | |
712 | * Fork becomes much lighter when there are big shared or private | |
713 | * readonly mappings. The tradeoff is that copy_page_range is more | |
714 | * efficient than faulting. | |
715 | */ | |
4d7672b4 | 716 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { |
d992895b NP |
717 | if (!vma->anon_vma) |
718 | return 0; | |
719 | } | |
720 | ||
1da177e4 LT |
721 | if (is_vm_hugetlb_page(vma)) |
722 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
723 | ||
34801ba9 | 724 | if (unlikely(is_pfn_mapping(vma))) { |
2ab64037 | 725 | /* |
726 | * We do not free on error cases below as remove_vma | |
727 | * gets called on error from higher level routine | |
728 | */ | |
729 | ret = track_pfn_vma_copy(vma); | |
730 | if (ret) | |
731 | return ret; | |
732 | } | |
733 | ||
cddb8a5c AA |
734 | /* |
735 | * We need to invalidate the secondary MMU mappings only when | |
736 | * there could be a permission downgrade on the ptes of the | |
737 | * parent mm. And a permission downgrade will only happen if | |
738 | * is_cow_mapping() returns true. | |
739 | */ | |
740 | if (is_cow_mapping(vma->vm_flags)) | |
741 | mmu_notifier_invalidate_range_start(src_mm, addr, end); | |
742 | ||
743 | ret = 0; | |
1da177e4 LT |
744 | dst_pgd = pgd_offset(dst_mm, addr); |
745 | src_pgd = pgd_offset(src_mm, addr); | |
746 | do { | |
747 | next = pgd_addr_end(addr, end); | |
748 | if (pgd_none_or_clear_bad(src_pgd)) | |
749 | continue; | |
cddb8a5c AA |
750 | if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
751 | vma, addr, next))) { | |
752 | ret = -ENOMEM; | |
753 | break; | |
754 | } | |
1da177e4 | 755 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
cddb8a5c AA |
756 | |
757 | if (is_cow_mapping(vma->vm_flags)) | |
758 | mmu_notifier_invalidate_range_end(src_mm, | |
759 | vma->vm_start, end); | |
760 | return ret; | |
1da177e4 LT |
761 | } |
762 | ||
51c6f666 | 763 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 764 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 765 | unsigned long addr, unsigned long end, |
51c6f666 | 766 | long *zap_work, struct zap_details *details) |
1da177e4 | 767 | { |
b5810039 | 768 | struct mm_struct *mm = tlb->mm; |
1da177e4 | 769 | pte_t *pte; |
508034a3 | 770 | spinlock_t *ptl; |
ae859762 HD |
771 | int file_rss = 0; |
772 | int anon_rss = 0; | |
1da177e4 | 773 | |
508034a3 | 774 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
6606c3e0 | 775 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
776 | do { |
777 | pte_t ptent = *pte; | |
51c6f666 RH |
778 | if (pte_none(ptent)) { |
779 | (*zap_work)--; | |
1da177e4 | 780 | continue; |
51c6f666 | 781 | } |
6f5e6b9e HD |
782 | |
783 | (*zap_work) -= PAGE_SIZE; | |
784 | ||
1da177e4 | 785 | if (pte_present(ptent)) { |
ee498ed7 | 786 | struct page *page; |
51c6f666 | 787 | |
6aab341e | 788 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
789 | if (unlikely(details) && page) { |
790 | /* | |
791 | * unmap_shared_mapping_pages() wants to | |
792 | * invalidate cache without truncating: | |
793 | * unmap shared but keep private pages. | |
794 | */ | |
795 | if (details->check_mapping && | |
796 | details->check_mapping != page->mapping) | |
797 | continue; | |
798 | /* | |
799 | * Each page->index must be checked when | |
800 | * invalidating or truncating nonlinear. | |
801 | */ | |
802 | if (details->nonlinear_vma && | |
803 | (page->index < details->first_index || | |
804 | page->index > details->last_index)) | |
805 | continue; | |
806 | } | |
b5810039 | 807 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 808 | tlb->fullmm); |
1da177e4 LT |
809 | tlb_remove_tlb_entry(tlb, pte, addr); |
810 | if (unlikely(!page)) | |
811 | continue; | |
812 | if (unlikely(details) && details->nonlinear_vma | |
813 | && linear_page_index(details->nonlinear_vma, | |
814 | addr) != page->index) | |
b5810039 | 815 | set_pte_at(mm, addr, pte, |
1da177e4 | 816 | pgoff_to_pte(page->index)); |
1da177e4 | 817 | if (PageAnon(page)) |
86d912f4 | 818 | anon_rss--; |
6237bcd9 HD |
819 | else { |
820 | if (pte_dirty(ptent)) | |
821 | set_page_dirty(page); | |
4917e5d0 JW |
822 | if (pte_young(ptent) && |
823 | likely(!VM_SequentialReadHint(vma))) | |
bf3f3bc5 | 824 | mark_page_accessed(page); |
86d912f4 | 825 | file_rss--; |
6237bcd9 | 826 | } |
edc315fd | 827 | page_remove_rmap(page); |
3dc14741 HD |
828 | if (unlikely(page_mapcount(page) < 0)) |
829 | print_bad_pte(vma, addr, ptent, page); | |
1da177e4 LT |
830 | tlb_remove_page(tlb, page); |
831 | continue; | |
832 | } | |
833 | /* | |
834 | * If details->check_mapping, we leave swap entries; | |
835 | * if details->nonlinear_vma, we leave file entries. | |
836 | */ | |
837 | if (unlikely(details)) | |
838 | continue; | |
2509ef26 HD |
839 | if (pte_file(ptent)) { |
840 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) | |
841 | print_bad_pte(vma, addr, ptent, NULL); | |
842 | } else if | |
843 | (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent)))) | |
844 | print_bad_pte(vma, addr, ptent, NULL); | |
9888a1ca | 845 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); |
51c6f666 | 846 | } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); |
ae859762 | 847 | |
86d912f4 | 848 | add_mm_rss(mm, file_rss, anon_rss); |
6606c3e0 | 849 | arch_leave_lazy_mmu_mode(); |
508034a3 | 850 | pte_unmap_unlock(pte - 1, ptl); |
51c6f666 RH |
851 | |
852 | return addr; | |
1da177e4 LT |
853 | } |
854 | ||
51c6f666 | 855 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 856 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 857 | unsigned long addr, unsigned long end, |
51c6f666 | 858 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
859 | { |
860 | pmd_t *pmd; | |
861 | unsigned long next; | |
862 | ||
863 | pmd = pmd_offset(pud, addr); | |
864 | do { | |
865 | next = pmd_addr_end(addr, end); | |
51c6f666 RH |
866 | if (pmd_none_or_clear_bad(pmd)) { |
867 | (*zap_work)--; | |
1da177e4 | 868 | continue; |
51c6f666 RH |
869 | } |
870 | next = zap_pte_range(tlb, vma, pmd, addr, next, | |
871 | zap_work, details); | |
872 | } while (pmd++, addr = next, (addr != end && *zap_work > 0)); | |
873 | ||
874 | return addr; | |
1da177e4 LT |
875 | } |
876 | ||
51c6f666 | 877 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 878 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 879 | unsigned long addr, unsigned long end, |
51c6f666 | 880 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
881 | { |
882 | pud_t *pud; | |
883 | unsigned long next; | |
884 | ||
885 | pud = pud_offset(pgd, addr); | |
886 | do { | |
887 | next = pud_addr_end(addr, end); | |
51c6f666 RH |
888 | if (pud_none_or_clear_bad(pud)) { |
889 | (*zap_work)--; | |
1da177e4 | 890 | continue; |
51c6f666 RH |
891 | } |
892 | next = zap_pmd_range(tlb, vma, pud, addr, next, | |
893 | zap_work, details); | |
894 | } while (pud++, addr = next, (addr != end && *zap_work > 0)); | |
895 | ||
896 | return addr; | |
1da177e4 LT |
897 | } |
898 | ||
51c6f666 RH |
899 | static unsigned long unmap_page_range(struct mmu_gather *tlb, |
900 | struct vm_area_struct *vma, | |
1da177e4 | 901 | unsigned long addr, unsigned long end, |
51c6f666 | 902 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
903 | { |
904 | pgd_t *pgd; | |
905 | unsigned long next; | |
906 | ||
907 | if (details && !details->check_mapping && !details->nonlinear_vma) | |
908 | details = NULL; | |
909 | ||
910 | BUG_ON(addr >= end); | |
911 | tlb_start_vma(tlb, vma); | |
912 | pgd = pgd_offset(vma->vm_mm, addr); | |
913 | do { | |
914 | next = pgd_addr_end(addr, end); | |
51c6f666 RH |
915 | if (pgd_none_or_clear_bad(pgd)) { |
916 | (*zap_work)--; | |
1da177e4 | 917 | continue; |
51c6f666 RH |
918 | } |
919 | next = zap_pud_range(tlb, vma, pgd, addr, next, | |
920 | zap_work, details); | |
921 | } while (pgd++, addr = next, (addr != end && *zap_work > 0)); | |
1da177e4 | 922 | tlb_end_vma(tlb, vma); |
51c6f666 RH |
923 | |
924 | return addr; | |
1da177e4 LT |
925 | } |
926 | ||
927 | #ifdef CONFIG_PREEMPT | |
928 | # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) | |
929 | #else | |
930 | /* No preempt: go for improved straight-line efficiency */ | |
931 | # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) | |
932 | #endif | |
933 | ||
934 | /** | |
935 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
936 | * @tlbp: address of the caller's struct mmu_gather | |
1da177e4 LT |
937 | * @vma: the starting vma |
938 | * @start_addr: virtual address at which to start unmapping | |
939 | * @end_addr: virtual address at which to end unmapping | |
940 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here | |
941 | * @details: details of nonlinear truncation or shared cache invalidation | |
942 | * | |
ee39b37b | 943 | * Returns the end address of the unmapping (restart addr if interrupted). |
1da177e4 | 944 | * |
508034a3 | 945 | * Unmap all pages in the vma list. |
1da177e4 | 946 | * |
508034a3 HD |
947 | * We aim to not hold locks for too long (for scheduling latency reasons). |
948 | * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to | |
1da177e4 LT |
949 | * return the ending mmu_gather to the caller. |
950 | * | |
951 | * Only addresses between `start' and `end' will be unmapped. | |
952 | * | |
953 | * The VMA list must be sorted in ascending virtual address order. | |
954 | * | |
955 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
956 | * range after unmap_vmas() returns. So the only responsibility here is to | |
957 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
958 | * drops the lock and schedules. | |
959 | */ | |
508034a3 | 960 | unsigned long unmap_vmas(struct mmu_gather **tlbp, |
1da177e4 LT |
961 | struct vm_area_struct *vma, unsigned long start_addr, |
962 | unsigned long end_addr, unsigned long *nr_accounted, | |
963 | struct zap_details *details) | |
964 | { | |
51c6f666 | 965 | long zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
966 | unsigned long tlb_start = 0; /* For tlb_finish_mmu */ |
967 | int tlb_start_valid = 0; | |
ee39b37b | 968 | unsigned long start = start_addr; |
1da177e4 | 969 | spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; |
4d6ddfa9 | 970 | int fullmm = (*tlbp)->fullmm; |
cddb8a5c | 971 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 972 | |
cddb8a5c | 973 | mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); |
1da177e4 | 974 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { |
1da177e4 LT |
975 | unsigned long end; |
976 | ||
977 | start = max(vma->vm_start, start_addr); | |
978 | if (start >= vma->vm_end) | |
979 | continue; | |
980 | end = min(vma->vm_end, end_addr); | |
981 | if (end <= vma->vm_start) | |
982 | continue; | |
983 | ||
984 | if (vma->vm_flags & VM_ACCOUNT) | |
985 | *nr_accounted += (end - start) >> PAGE_SHIFT; | |
986 | ||
34801ba9 | 987 | if (unlikely(is_pfn_mapping(vma))) |
2ab64037 | 988 | untrack_pfn_vma(vma, 0, 0); |
989 | ||
1da177e4 | 990 | while (start != end) { |
1da177e4 LT |
991 | if (!tlb_start_valid) { |
992 | tlb_start = start; | |
993 | tlb_start_valid = 1; | |
994 | } | |
995 | ||
51c6f666 | 996 | if (unlikely(is_vm_hugetlb_page(vma))) { |
a137e1cc AK |
997 | /* |
998 | * It is undesirable to test vma->vm_file as it | |
999 | * should be non-null for valid hugetlb area. | |
1000 | * However, vm_file will be NULL in the error | |
1001 | * cleanup path of do_mmap_pgoff. When | |
1002 | * hugetlbfs ->mmap method fails, | |
1003 | * do_mmap_pgoff() nullifies vma->vm_file | |
1004 | * before calling this function to clean up. | |
1005 | * Since no pte has actually been setup, it is | |
1006 | * safe to do nothing in this case. | |
1007 | */ | |
1008 | if (vma->vm_file) { | |
1009 | unmap_hugepage_range(vma, start, end, NULL); | |
1010 | zap_work -= (end - start) / | |
a5516438 | 1011 | pages_per_huge_page(hstate_vma(vma)); |
a137e1cc AK |
1012 | } |
1013 | ||
51c6f666 RH |
1014 | start = end; |
1015 | } else | |
1016 | start = unmap_page_range(*tlbp, vma, | |
1017 | start, end, &zap_work, details); | |
1018 | ||
1019 | if (zap_work > 0) { | |
1020 | BUG_ON(start != end); | |
1021 | break; | |
1da177e4 LT |
1022 | } |
1023 | ||
1da177e4 LT |
1024 | tlb_finish_mmu(*tlbp, tlb_start, start); |
1025 | ||
1026 | if (need_resched() || | |
95c354fe | 1027 | (i_mmap_lock && spin_needbreak(i_mmap_lock))) { |
1da177e4 | 1028 | if (i_mmap_lock) { |
508034a3 | 1029 | *tlbp = NULL; |
1da177e4 LT |
1030 | goto out; |
1031 | } | |
1da177e4 | 1032 | cond_resched(); |
1da177e4 LT |
1033 | } |
1034 | ||
508034a3 | 1035 | *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); |
1da177e4 | 1036 | tlb_start_valid = 0; |
51c6f666 | 1037 | zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
1038 | } |
1039 | } | |
1040 | out: | |
cddb8a5c | 1041 | mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); |
ee39b37b | 1042 | return start; /* which is now the end (or restart) address */ |
1da177e4 LT |
1043 | } |
1044 | ||
1045 | /** | |
1046 | * zap_page_range - remove user pages in a given range | |
1047 | * @vma: vm_area_struct holding the applicable pages | |
1048 | * @address: starting address of pages to zap | |
1049 | * @size: number of bytes to zap | |
1050 | * @details: details of nonlinear truncation or shared cache invalidation | |
1051 | */ | |
ee39b37b | 1052 | unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
1053 | unsigned long size, struct zap_details *details) |
1054 | { | |
1055 | struct mm_struct *mm = vma->vm_mm; | |
1056 | struct mmu_gather *tlb; | |
1057 | unsigned long end = address + size; | |
1058 | unsigned long nr_accounted = 0; | |
1059 | ||
1da177e4 | 1060 | lru_add_drain(); |
1da177e4 | 1061 | tlb = tlb_gather_mmu(mm, 0); |
365e9c87 | 1062 | update_hiwater_rss(mm); |
508034a3 HD |
1063 | end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); |
1064 | if (tlb) | |
1065 | tlb_finish_mmu(tlb, address, end); | |
ee39b37b | 1066 | return end; |
1da177e4 LT |
1067 | } |
1068 | ||
c627f9cc JS |
1069 | /** |
1070 | * zap_vma_ptes - remove ptes mapping the vma | |
1071 | * @vma: vm_area_struct holding ptes to be zapped | |
1072 | * @address: starting address of pages to zap | |
1073 | * @size: number of bytes to zap | |
1074 | * | |
1075 | * This function only unmaps ptes assigned to VM_PFNMAP vmas. | |
1076 | * | |
1077 | * The entire address range must be fully contained within the vma. | |
1078 | * | |
1079 | * Returns 0 if successful. | |
1080 | */ | |
1081 | int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, | |
1082 | unsigned long size) | |
1083 | { | |
1084 | if (address < vma->vm_start || address + size > vma->vm_end || | |
1085 | !(vma->vm_flags & VM_PFNMAP)) | |
1086 | return -1; | |
1087 | zap_page_range(vma, address, size, NULL); | |
1088 | return 0; | |
1089 | } | |
1090 | EXPORT_SYMBOL_GPL(zap_vma_ptes); | |
1091 | ||
1da177e4 LT |
1092 | /* |
1093 | * Do a quick page-table lookup for a single page. | |
1da177e4 | 1094 | */ |
6aab341e | 1095 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1096 | unsigned int flags) |
1da177e4 LT |
1097 | { |
1098 | pgd_t *pgd; | |
1099 | pud_t *pud; | |
1100 | pmd_t *pmd; | |
1101 | pte_t *ptep, pte; | |
deceb6cd | 1102 | spinlock_t *ptl; |
1da177e4 | 1103 | struct page *page; |
6aab341e | 1104 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1105 | |
deceb6cd HD |
1106 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
1107 | if (!IS_ERR(page)) { | |
1108 | BUG_ON(flags & FOLL_GET); | |
1109 | goto out; | |
1110 | } | |
1da177e4 | 1111 | |
deceb6cd | 1112 | page = NULL; |
1da177e4 LT |
1113 | pgd = pgd_offset(mm, address); |
1114 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
deceb6cd | 1115 | goto no_page_table; |
1da177e4 LT |
1116 | |
1117 | pud = pud_offset(pgd, address); | |
ceb86879 | 1118 | if (pud_none(*pud)) |
deceb6cd | 1119 | goto no_page_table; |
ceb86879 AK |
1120 | if (pud_huge(*pud)) { |
1121 | BUG_ON(flags & FOLL_GET); | |
1122 | page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE); | |
1123 | goto out; | |
1124 | } | |
1125 | if (unlikely(pud_bad(*pud))) | |
1126 | goto no_page_table; | |
1127 | ||
1da177e4 | 1128 | pmd = pmd_offset(pud, address); |
aeed5fce | 1129 | if (pmd_none(*pmd)) |
deceb6cd | 1130 | goto no_page_table; |
deceb6cd HD |
1131 | if (pmd_huge(*pmd)) { |
1132 | BUG_ON(flags & FOLL_GET); | |
1133 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); | |
1da177e4 | 1134 | goto out; |
deceb6cd | 1135 | } |
aeed5fce HD |
1136 | if (unlikely(pmd_bad(*pmd))) |
1137 | goto no_page_table; | |
1138 | ||
deceb6cd | 1139 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
1140 | |
1141 | pte = *ptep; | |
deceb6cd | 1142 | if (!pte_present(pte)) |
89f5b7da | 1143 | goto no_page; |
deceb6cd HD |
1144 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
1145 | goto unlock; | |
6aab341e LT |
1146 | page = vm_normal_page(vma, address, pte); |
1147 | if (unlikely(!page)) | |
89f5b7da | 1148 | goto bad_page; |
1da177e4 | 1149 | |
deceb6cd HD |
1150 | if (flags & FOLL_GET) |
1151 | get_page(page); | |
1152 | if (flags & FOLL_TOUCH) { | |
1153 | if ((flags & FOLL_WRITE) && | |
1154 | !pte_dirty(pte) && !PageDirty(page)) | |
1155 | set_page_dirty(page); | |
bd775c42 KM |
1156 | /* |
1157 | * pte_mkyoung() would be more correct here, but atomic care | |
1158 | * is needed to avoid losing the dirty bit: it is easier to use | |
1159 | * mark_page_accessed(). | |
1160 | */ | |
deceb6cd HD |
1161 | mark_page_accessed(page); |
1162 | } | |
1163 | unlock: | |
1164 | pte_unmap_unlock(ptep, ptl); | |
1da177e4 | 1165 | out: |
deceb6cd | 1166 | return page; |
1da177e4 | 1167 | |
89f5b7da LT |
1168 | bad_page: |
1169 | pte_unmap_unlock(ptep, ptl); | |
1170 | return ERR_PTR(-EFAULT); | |
1171 | ||
1172 | no_page: | |
1173 | pte_unmap_unlock(ptep, ptl); | |
1174 | if (!pte_none(pte)) | |
1175 | return page; | |
1176 | /* Fall through to ZERO_PAGE handling */ | |
deceb6cd HD |
1177 | no_page_table: |
1178 | /* | |
1179 | * When core dumping an enormous anonymous area that nobody | |
1180 | * has touched so far, we don't want to allocate page tables. | |
1181 | */ | |
1182 | if (flags & FOLL_ANON) { | |
557ed1fa | 1183 | page = ZERO_PAGE(0); |
deceb6cd HD |
1184 | if (flags & FOLL_GET) |
1185 | get_page(page); | |
1186 | BUG_ON(flags & FOLL_WRITE); | |
1187 | } | |
1188 | return page; | |
1da177e4 LT |
1189 | } |
1190 | ||
672ca28e LT |
1191 | /* Can we do the FOLL_ANON optimization? */ |
1192 | static inline int use_zero_page(struct vm_area_struct *vma) | |
1193 | { | |
1194 | /* | |
1195 | * We don't want to optimize FOLL_ANON for make_pages_present() | |
1196 | * when it tries to page in a VM_LOCKED region. As to VM_SHARED, | |
1197 | * we want to get the page from the page tables to make sure | |
1198 | * that we serialize and update with any other user of that | |
1199 | * mapping. | |
1200 | */ | |
1201 | if (vma->vm_flags & (VM_LOCKED | VM_SHARED)) | |
1202 | return 0; | |
1203 | /* | |
0d71d10a | 1204 | * And if we have a fault routine, it's not an anonymous region. |
672ca28e | 1205 | */ |
0d71d10a | 1206 | return !vma->vm_ops || !vma->vm_ops->fault; |
672ca28e LT |
1207 | } |
1208 | ||
b291f000 NP |
1209 | |
1210 | ||
1211 | int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | |
9d73777e PZ |
1212 | unsigned long start, int nr_pages, int flags, |
1213 | struct page **pages, struct vm_area_struct **vmas) | |
1da177e4 LT |
1214 | { |
1215 | int i; | |
b291f000 NP |
1216 | unsigned int vm_flags = 0; |
1217 | int write = !!(flags & GUP_FLAGS_WRITE); | |
1218 | int force = !!(flags & GUP_FLAGS_FORCE); | |
1219 | int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS); | |
4779280d | 1220 | int ignore_sigkill = !!(flags & GUP_FLAGS_IGNORE_SIGKILL); |
1da177e4 | 1221 | |
9d73777e | 1222 | if (nr_pages <= 0) |
900cf086 | 1223 | return 0; |
1da177e4 LT |
1224 | /* |
1225 | * Require read or write permissions. | |
1226 | * If 'force' is set, we only require the "MAY" flags. | |
1227 | */ | |
deceb6cd HD |
1228 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
1229 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 LT |
1230 | i = 0; |
1231 | ||
1232 | do { | |
deceb6cd HD |
1233 | struct vm_area_struct *vma; |
1234 | unsigned int foll_flags; | |
1da177e4 LT |
1235 | |
1236 | vma = find_extend_vma(mm, start); | |
1237 | if (!vma && in_gate_area(tsk, start)) { | |
1238 | unsigned long pg = start & PAGE_MASK; | |
1239 | struct vm_area_struct *gate_vma = get_gate_vma(tsk); | |
1240 | pgd_t *pgd; | |
1241 | pud_t *pud; | |
1242 | pmd_t *pmd; | |
1243 | pte_t *pte; | |
b291f000 NP |
1244 | |
1245 | /* user gate pages are read-only */ | |
1246 | if (!ignore && write) | |
1da177e4 LT |
1247 | return i ? : -EFAULT; |
1248 | if (pg > TASK_SIZE) | |
1249 | pgd = pgd_offset_k(pg); | |
1250 | else | |
1251 | pgd = pgd_offset_gate(mm, pg); | |
1252 | BUG_ON(pgd_none(*pgd)); | |
1253 | pud = pud_offset(pgd, pg); | |
1254 | BUG_ON(pud_none(*pud)); | |
1255 | pmd = pmd_offset(pud, pg); | |
690dbe1c HD |
1256 | if (pmd_none(*pmd)) |
1257 | return i ? : -EFAULT; | |
1da177e4 | 1258 | pte = pte_offset_map(pmd, pg); |
690dbe1c HD |
1259 | if (pte_none(*pte)) { |
1260 | pte_unmap(pte); | |
1261 | return i ? : -EFAULT; | |
1262 | } | |
1da177e4 | 1263 | if (pages) { |
fa2a455b | 1264 | struct page *page = vm_normal_page(gate_vma, start, *pte); |
6aab341e LT |
1265 | pages[i] = page; |
1266 | if (page) | |
1267 | get_page(page); | |
1da177e4 LT |
1268 | } |
1269 | pte_unmap(pte); | |
1270 | if (vmas) | |
1271 | vmas[i] = gate_vma; | |
1272 | i++; | |
1273 | start += PAGE_SIZE; | |
9d73777e | 1274 | nr_pages--; |
1da177e4 LT |
1275 | continue; |
1276 | } | |
1277 | ||
b291f000 NP |
1278 | if (!vma || |
1279 | (vma->vm_flags & (VM_IO | VM_PFNMAP)) || | |
1280 | (!ignore && !(vm_flags & vma->vm_flags))) | |
1da177e4 LT |
1281 | return i ? : -EFAULT; |
1282 | ||
1283 | if (is_vm_hugetlb_page(vma)) { | |
1284 | i = follow_hugetlb_page(mm, vma, pages, vmas, | |
9d73777e | 1285 | &start, &nr_pages, i, write); |
1da177e4 LT |
1286 | continue; |
1287 | } | |
deceb6cd HD |
1288 | |
1289 | foll_flags = FOLL_TOUCH; | |
1290 | if (pages) | |
1291 | foll_flags |= FOLL_GET; | |
672ca28e | 1292 | if (!write && use_zero_page(vma)) |
deceb6cd HD |
1293 | foll_flags |= FOLL_ANON; |
1294 | ||
1da177e4 | 1295 | do { |
08ef4729 | 1296 | struct page *page; |
1da177e4 | 1297 | |
462e00cc | 1298 | /* |
4779280d YH |
1299 | * If we have a pending SIGKILL, don't keep faulting |
1300 | * pages and potentially allocating memory, unless | |
1301 | * current is handling munlock--e.g., on exit. In | |
1302 | * that case, we are not allocating memory. Rather, | |
1303 | * we're only unlocking already resident/mapped pages. | |
462e00cc | 1304 | */ |
4779280d YH |
1305 | if (unlikely(!ignore_sigkill && |
1306 | fatal_signal_pending(current))) | |
1307 | return i ? i : -ERESTARTSYS; | |
462e00cc | 1308 | |
deceb6cd HD |
1309 | if (write) |
1310 | foll_flags |= FOLL_WRITE; | |
a68d2ebc | 1311 | |
deceb6cd | 1312 | cond_resched(); |
6aab341e | 1313 | while (!(page = follow_page(vma, start, foll_flags))) { |
deceb6cd | 1314 | int ret; |
d06063cc | 1315 | |
d26ed650 HD |
1316 | ret = handle_mm_fault(mm, vma, start, |
1317 | (foll_flags & FOLL_WRITE) ? | |
1318 | FAULT_FLAG_WRITE : 0); | |
1319 | ||
83c54070 NP |
1320 | if (ret & VM_FAULT_ERROR) { |
1321 | if (ret & VM_FAULT_OOM) | |
1322 | return i ? i : -ENOMEM; | |
1323 | else if (ret & VM_FAULT_SIGBUS) | |
1324 | return i ? i : -EFAULT; | |
1325 | BUG(); | |
1326 | } | |
1327 | if (ret & VM_FAULT_MAJOR) | |
1328 | tsk->maj_flt++; | |
1329 | else | |
1330 | tsk->min_flt++; | |
1331 | ||
a68d2ebc | 1332 | /* |
83c54070 NP |
1333 | * The VM_FAULT_WRITE bit tells us that |
1334 | * do_wp_page has broken COW when necessary, | |
1335 | * even if maybe_mkwrite decided not to set | |
1336 | * pte_write. We can thus safely do subsequent | |
878b63ac HD |
1337 | * page lookups as if they were reads. But only |
1338 | * do so when looping for pte_write is futile: | |
1339 | * in some cases userspace may also be wanting | |
1340 | * to write to the gotten user page, which a | |
1341 | * read fault here might prevent (a readonly | |
1342 | * page might get reCOWed by userspace write). | |
a68d2ebc | 1343 | */ |
878b63ac HD |
1344 | if ((ret & VM_FAULT_WRITE) && |
1345 | !(vma->vm_flags & VM_WRITE)) | |
deceb6cd | 1346 | foll_flags &= ~FOLL_WRITE; |
83c54070 | 1347 | |
7f7bbbe5 | 1348 | cond_resched(); |
1da177e4 | 1349 | } |
89f5b7da LT |
1350 | if (IS_ERR(page)) |
1351 | return i ? i : PTR_ERR(page); | |
1da177e4 | 1352 | if (pages) { |
08ef4729 | 1353 | pages[i] = page; |
03beb076 | 1354 | |
a6f36be3 | 1355 | flush_anon_page(vma, page, start); |
08ef4729 | 1356 | flush_dcache_page(page); |
1da177e4 LT |
1357 | } |
1358 | if (vmas) | |
1359 | vmas[i] = vma; | |
1360 | i++; | |
1361 | start += PAGE_SIZE; | |
9d73777e PZ |
1362 | nr_pages--; |
1363 | } while (nr_pages && start < vma->vm_end); | |
1364 | } while (nr_pages); | |
1da177e4 LT |
1365 | return i; |
1366 | } | |
b291f000 | 1367 | |
d2bf6be8 NP |
1368 | /** |
1369 | * get_user_pages() - pin user pages in memory | |
1370 | * @tsk: task_struct of target task | |
1371 | * @mm: mm_struct of target mm | |
1372 | * @start: starting user address | |
9d73777e | 1373 | * @nr_pages: number of pages from start to pin |
d2bf6be8 NP |
1374 | * @write: whether pages will be written to by the caller |
1375 | * @force: whether to force write access even if user mapping is | |
1376 | * readonly. This will result in the page being COWed even | |
1377 | * in MAP_SHARED mappings. You do not want this. | |
1378 | * @pages: array that receives pointers to the pages pinned. | |
1379 | * Should be at least nr_pages long. Or NULL, if caller | |
1380 | * only intends to ensure the pages are faulted in. | |
1381 | * @vmas: array of pointers to vmas corresponding to each page. | |
1382 | * Or NULL if the caller does not require them. | |
1383 | * | |
1384 | * Returns number of pages pinned. This may be fewer than the number | |
9d73777e | 1385 | * requested. If nr_pages is 0 or negative, returns 0. If no pages |
d2bf6be8 NP |
1386 | * were pinned, returns -errno. Each page returned must be released |
1387 | * with a put_page() call when it is finished with. vmas will only | |
1388 | * remain valid while mmap_sem is held. | |
1389 | * | |
1390 | * Must be called with mmap_sem held for read or write. | |
1391 | * | |
1392 | * get_user_pages walks a process's page tables and takes a reference to | |
1393 | * each struct page that each user address corresponds to at a given | |
1394 | * instant. That is, it takes the page that would be accessed if a user | |
1395 | * thread accesses the given user virtual address at that instant. | |
1396 | * | |
1397 | * This does not guarantee that the page exists in the user mappings when | |
1398 | * get_user_pages returns, and there may even be a completely different | |
1399 | * page there in some cases (eg. if mmapped pagecache has been invalidated | |
1400 | * and subsequently re faulted). However it does guarantee that the page | |
1401 | * won't be freed completely. And mostly callers simply care that the page | |
1402 | * contains data that was valid *at some point in time*. Typically, an IO | |
1403 | * or similar operation cannot guarantee anything stronger anyway because | |
1404 | * locks can't be held over the syscall boundary. | |
1405 | * | |
1406 | * If write=0, the page must not be written to. If the page is written to, | |
1407 | * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called | |
1408 | * after the page is finished with, and before put_page is called. | |
1409 | * | |
1410 | * get_user_pages is typically used for fewer-copy IO operations, to get a | |
1411 | * handle on the memory by some means other than accesses via the user virtual | |
1412 | * addresses. The pages may be submitted for DMA to devices or accessed via | |
1413 | * their kernel linear mapping (via the kmap APIs). Care should be taken to | |
1414 | * use the correct cache flushing APIs. | |
1415 | * | |
1416 | * See also get_user_pages_fast, for performance critical applications. | |
1417 | */ | |
b291f000 | 1418 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
9d73777e | 1419 | unsigned long start, int nr_pages, int write, int force, |
b291f000 NP |
1420 | struct page **pages, struct vm_area_struct **vmas) |
1421 | { | |
1422 | int flags = 0; | |
1423 | ||
1424 | if (write) | |
1425 | flags |= GUP_FLAGS_WRITE; | |
1426 | if (force) | |
1427 | flags |= GUP_FLAGS_FORCE; | |
1428 | ||
9d73777e | 1429 | return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas); |
b291f000 NP |
1430 | } |
1431 | ||
1da177e4 LT |
1432 | EXPORT_SYMBOL(get_user_pages); |
1433 | ||
920c7a5d HH |
1434 | pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, |
1435 | spinlock_t **ptl) | |
c9cfcddf LT |
1436 | { |
1437 | pgd_t * pgd = pgd_offset(mm, addr); | |
1438 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
1439 | if (pud) { | |
49c91fb0 | 1440 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
c9cfcddf LT |
1441 | if (pmd) |
1442 | return pte_alloc_map_lock(mm, pmd, addr, ptl); | |
1443 | } | |
1444 | return NULL; | |
1445 | } | |
1446 | ||
238f58d8 LT |
1447 | /* |
1448 | * This is the old fallback for page remapping. | |
1449 | * | |
1450 | * For historical reasons, it only allows reserved pages. Only | |
1451 | * old drivers should use this, and they needed to mark their | |
1452 | * pages reserved for the old functions anyway. | |
1453 | */ | |
423bad60 NP |
1454 | static int insert_page(struct vm_area_struct *vma, unsigned long addr, |
1455 | struct page *page, pgprot_t prot) | |
238f58d8 | 1456 | { |
423bad60 | 1457 | struct mm_struct *mm = vma->vm_mm; |
238f58d8 | 1458 | int retval; |
c9cfcddf | 1459 | pte_t *pte; |
8a9f3ccd BS |
1460 | spinlock_t *ptl; |
1461 | ||
238f58d8 | 1462 | retval = -EINVAL; |
a145dd41 | 1463 | if (PageAnon(page)) |
5b4e655e | 1464 | goto out; |
238f58d8 LT |
1465 | retval = -ENOMEM; |
1466 | flush_dcache_page(page); | |
c9cfcddf | 1467 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 | 1468 | if (!pte) |
5b4e655e | 1469 | goto out; |
238f58d8 LT |
1470 | retval = -EBUSY; |
1471 | if (!pte_none(*pte)) | |
1472 | goto out_unlock; | |
1473 | ||
1474 | /* Ok, finally just insert the thing.. */ | |
1475 | get_page(page); | |
1476 | inc_mm_counter(mm, file_rss); | |
1477 | page_add_file_rmap(page); | |
1478 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); | |
1479 | ||
1480 | retval = 0; | |
8a9f3ccd BS |
1481 | pte_unmap_unlock(pte, ptl); |
1482 | return retval; | |
238f58d8 LT |
1483 | out_unlock: |
1484 | pte_unmap_unlock(pte, ptl); | |
1485 | out: | |
1486 | return retval; | |
1487 | } | |
1488 | ||
bfa5bf6d REB |
1489 | /** |
1490 | * vm_insert_page - insert single page into user vma | |
1491 | * @vma: user vma to map to | |
1492 | * @addr: target user address of this page | |
1493 | * @page: source kernel page | |
1494 | * | |
a145dd41 LT |
1495 | * This allows drivers to insert individual pages they've allocated |
1496 | * into a user vma. | |
1497 | * | |
1498 | * The page has to be a nice clean _individual_ kernel allocation. | |
1499 | * If you allocate a compound page, you need to have marked it as | |
1500 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 1501 | * (see split_page()). |
a145dd41 LT |
1502 | * |
1503 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
1504 | * took an arbitrary page protection parameter. This doesn't allow | |
1505 | * that. Your vma protection will have to be set up correctly, which | |
1506 | * means that if you want a shared writable mapping, you'd better | |
1507 | * ask for a shared writable mapping! | |
1508 | * | |
1509 | * The page does not need to be reserved. | |
1510 | */ | |
423bad60 NP |
1511 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
1512 | struct page *page) | |
a145dd41 LT |
1513 | { |
1514 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1515 | return -EFAULT; | |
1516 | if (!page_count(page)) | |
1517 | return -EINVAL; | |
4d7672b4 | 1518 | vma->vm_flags |= VM_INSERTPAGE; |
423bad60 | 1519 | return insert_page(vma, addr, page, vma->vm_page_prot); |
a145dd41 | 1520 | } |
e3c3374f | 1521 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 1522 | |
423bad60 NP |
1523 | static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, |
1524 | unsigned long pfn, pgprot_t prot) | |
1525 | { | |
1526 | struct mm_struct *mm = vma->vm_mm; | |
1527 | int retval; | |
1528 | pte_t *pte, entry; | |
1529 | spinlock_t *ptl; | |
1530 | ||
1531 | retval = -ENOMEM; | |
1532 | pte = get_locked_pte(mm, addr, &ptl); | |
1533 | if (!pte) | |
1534 | goto out; | |
1535 | retval = -EBUSY; | |
1536 | if (!pte_none(*pte)) | |
1537 | goto out_unlock; | |
1538 | ||
1539 | /* Ok, finally just insert the thing.. */ | |
1540 | entry = pte_mkspecial(pfn_pte(pfn, prot)); | |
1541 | set_pte_at(mm, addr, pte, entry); | |
1542 | update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */ | |
1543 | ||
1544 | retval = 0; | |
1545 | out_unlock: | |
1546 | pte_unmap_unlock(pte, ptl); | |
1547 | out: | |
1548 | return retval; | |
1549 | } | |
1550 | ||
e0dc0d8f NP |
1551 | /** |
1552 | * vm_insert_pfn - insert single pfn into user vma | |
1553 | * @vma: user vma to map to | |
1554 | * @addr: target user address of this page | |
1555 | * @pfn: source kernel pfn | |
1556 | * | |
1557 | * Similar to vm_inert_page, this allows drivers to insert individual pages | |
1558 | * they've allocated into a user vma. Same comments apply. | |
1559 | * | |
1560 | * This function should only be called from a vm_ops->fault handler, and | |
1561 | * in that case the handler should return NULL. | |
0d71d10a NP |
1562 | * |
1563 | * vma cannot be a COW mapping. | |
1564 | * | |
1565 | * As this is called only for pages that do not currently exist, we | |
1566 | * do not need to flush old virtual caches or the TLB. | |
e0dc0d8f NP |
1567 | */ |
1568 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
423bad60 | 1569 | unsigned long pfn) |
e0dc0d8f | 1570 | { |
2ab64037 | 1571 | int ret; |
e4b866ed | 1572 | pgprot_t pgprot = vma->vm_page_prot; |
7e675137 NP |
1573 | /* |
1574 | * Technically, architectures with pte_special can avoid all these | |
1575 | * restrictions (same for remap_pfn_range). However we would like | |
1576 | * consistency in testing and feature parity among all, so we should | |
1577 | * try to keep these invariants in place for everybody. | |
1578 | */ | |
b379d790 JH |
1579 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); |
1580 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
1581 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1582 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
1583 | BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); | |
e0dc0d8f | 1584 | |
423bad60 NP |
1585 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1586 | return -EFAULT; | |
e4b866ed | 1587 | if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE)) |
2ab64037 | 1588 | return -EINVAL; |
1589 | ||
e4b866ed | 1590 | ret = insert_pfn(vma, addr, pfn, pgprot); |
2ab64037 | 1591 | |
1592 | if (ret) | |
1593 | untrack_pfn_vma(vma, pfn, PAGE_SIZE); | |
1594 | ||
1595 | return ret; | |
423bad60 NP |
1596 | } |
1597 | EXPORT_SYMBOL(vm_insert_pfn); | |
e0dc0d8f | 1598 | |
423bad60 NP |
1599 | int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, |
1600 | unsigned long pfn) | |
1601 | { | |
1602 | BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); | |
e0dc0d8f | 1603 | |
423bad60 NP |
1604 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1605 | return -EFAULT; | |
e0dc0d8f | 1606 | |
423bad60 NP |
1607 | /* |
1608 | * If we don't have pte special, then we have to use the pfn_valid() | |
1609 | * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* | |
1610 | * refcount the page if pfn_valid is true (hence insert_page rather | |
1611 | * than insert_pfn). | |
1612 | */ | |
1613 | if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) { | |
1614 | struct page *page; | |
1615 | ||
1616 | page = pfn_to_page(pfn); | |
1617 | return insert_page(vma, addr, page, vma->vm_page_prot); | |
1618 | } | |
1619 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
e0dc0d8f | 1620 | } |
423bad60 | 1621 | EXPORT_SYMBOL(vm_insert_mixed); |
e0dc0d8f | 1622 | |
1da177e4 LT |
1623 | /* |
1624 | * maps a range of physical memory into the requested pages. the old | |
1625 | * mappings are removed. any references to nonexistent pages results | |
1626 | * in null mappings (currently treated as "copy-on-access") | |
1627 | */ | |
1628 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
1629 | unsigned long addr, unsigned long end, | |
1630 | unsigned long pfn, pgprot_t prot) | |
1631 | { | |
1632 | pte_t *pte; | |
c74df32c | 1633 | spinlock_t *ptl; |
1da177e4 | 1634 | |
c74df32c | 1635 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
1636 | if (!pte) |
1637 | return -ENOMEM; | |
6606c3e0 | 1638 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1639 | do { |
1640 | BUG_ON(!pte_none(*pte)); | |
7e675137 | 1641 | set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); |
1da177e4 LT |
1642 | pfn++; |
1643 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 1644 | arch_leave_lazy_mmu_mode(); |
c74df32c | 1645 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
1646 | return 0; |
1647 | } | |
1648 | ||
1649 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1650 | unsigned long addr, unsigned long end, | |
1651 | unsigned long pfn, pgprot_t prot) | |
1652 | { | |
1653 | pmd_t *pmd; | |
1654 | unsigned long next; | |
1655 | ||
1656 | pfn -= addr >> PAGE_SHIFT; | |
1657 | pmd = pmd_alloc(mm, pud, addr); | |
1658 | if (!pmd) | |
1659 | return -ENOMEM; | |
1660 | do { | |
1661 | next = pmd_addr_end(addr, end); | |
1662 | if (remap_pte_range(mm, pmd, addr, next, | |
1663 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1664 | return -ENOMEM; | |
1665 | } while (pmd++, addr = next, addr != end); | |
1666 | return 0; | |
1667 | } | |
1668 | ||
1669 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1670 | unsigned long addr, unsigned long end, | |
1671 | unsigned long pfn, pgprot_t prot) | |
1672 | { | |
1673 | pud_t *pud; | |
1674 | unsigned long next; | |
1675 | ||
1676 | pfn -= addr >> PAGE_SHIFT; | |
1677 | pud = pud_alloc(mm, pgd, addr); | |
1678 | if (!pud) | |
1679 | return -ENOMEM; | |
1680 | do { | |
1681 | next = pud_addr_end(addr, end); | |
1682 | if (remap_pmd_range(mm, pud, addr, next, | |
1683 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1684 | return -ENOMEM; | |
1685 | } while (pud++, addr = next, addr != end); | |
1686 | return 0; | |
1687 | } | |
1688 | ||
bfa5bf6d REB |
1689 | /** |
1690 | * remap_pfn_range - remap kernel memory to userspace | |
1691 | * @vma: user vma to map to | |
1692 | * @addr: target user address to start at | |
1693 | * @pfn: physical address of kernel memory | |
1694 | * @size: size of map area | |
1695 | * @prot: page protection flags for this mapping | |
1696 | * | |
1697 | * Note: this is only safe if the mm semaphore is held when called. | |
1698 | */ | |
1da177e4 LT |
1699 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
1700 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
1701 | { | |
1702 | pgd_t *pgd; | |
1703 | unsigned long next; | |
2d15cab8 | 1704 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 LT |
1705 | struct mm_struct *mm = vma->vm_mm; |
1706 | int err; | |
1707 | ||
1708 | /* | |
1709 | * Physically remapped pages are special. Tell the | |
1710 | * rest of the world about it: | |
1711 | * VM_IO tells people not to look at these pages | |
1712 | * (accesses can have side effects). | |
0b14c179 HD |
1713 | * VM_RESERVED is specified all over the place, because |
1714 | * in 2.4 it kept swapout's vma scan off this vma; but | |
1715 | * in 2.6 the LRU scan won't even find its pages, so this | |
1716 | * flag means no more than count its pages in reserved_vm, | |
1717 | * and omit it from core dump, even when VM_IO turned off. | |
6aab341e LT |
1718 | * VM_PFNMAP tells the core MM that the base pages are just |
1719 | * raw PFN mappings, and do not have a "struct page" associated | |
1720 | * with them. | |
fb155c16 LT |
1721 | * |
1722 | * There's a horrible special case to handle copy-on-write | |
1723 | * behaviour that some programs depend on. We mark the "original" | |
1724 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
1da177e4 | 1725 | */ |
4bb9c5c0 | 1726 | if (addr == vma->vm_start && end == vma->vm_end) { |
fb155c16 | 1727 | vma->vm_pgoff = pfn; |
895791da | 1728 | vma->vm_flags |= VM_PFN_AT_MMAP; |
4bb9c5c0 | 1729 | } else if (is_cow_mapping(vma->vm_flags)) |
3c8bb73a | 1730 | return -EINVAL; |
fb155c16 | 1731 | |
6aab341e | 1732 | vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; |
1da177e4 | 1733 | |
e4b866ed | 1734 | err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size)); |
a3670613 | 1735 | if (err) { |
1736 | /* | |
1737 | * To indicate that track_pfn related cleanup is not | |
1738 | * needed from higher level routine calling unmap_vmas | |
1739 | */ | |
1740 | vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP); | |
895791da | 1741 | vma->vm_flags &= ~VM_PFN_AT_MMAP; |
2ab64037 | 1742 | return -EINVAL; |
a3670613 | 1743 | } |
2ab64037 | 1744 | |
1da177e4 LT |
1745 | BUG_ON(addr >= end); |
1746 | pfn -= addr >> PAGE_SHIFT; | |
1747 | pgd = pgd_offset(mm, addr); | |
1748 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
1749 | do { |
1750 | next = pgd_addr_end(addr, end); | |
1751 | err = remap_pud_range(mm, pgd, addr, next, | |
1752 | pfn + (addr >> PAGE_SHIFT), prot); | |
1753 | if (err) | |
1754 | break; | |
1755 | } while (pgd++, addr = next, addr != end); | |
2ab64037 | 1756 | |
1757 | if (err) | |
1758 | untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size)); | |
1759 | ||
1da177e4 LT |
1760 | return err; |
1761 | } | |
1762 | EXPORT_SYMBOL(remap_pfn_range); | |
1763 | ||
aee16b3c JF |
1764 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
1765 | unsigned long addr, unsigned long end, | |
1766 | pte_fn_t fn, void *data) | |
1767 | { | |
1768 | pte_t *pte; | |
1769 | int err; | |
2f569afd | 1770 | pgtable_t token; |
94909914 | 1771 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
1772 | |
1773 | pte = (mm == &init_mm) ? | |
1774 | pte_alloc_kernel(pmd, addr) : | |
1775 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
1776 | if (!pte) | |
1777 | return -ENOMEM; | |
1778 | ||
1779 | BUG_ON(pmd_huge(*pmd)); | |
1780 | ||
38e0edb1 JF |
1781 | arch_enter_lazy_mmu_mode(); |
1782 | ||
2f569afd | 1783 | token = pmd_pgtable(*pmd); |
aee16b3c JF |
1784 | |
1785 | do { | |
2f569afd | 1786 | err = fn(pte, token, addr, data); |
aee16b3c JF |
1787 | if (err) |
1788 | break; | |
1789 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
1790 | ||
38e0edb1 JF |
1791 | arch_leave_lazy_mmu_mode(); |
1792 | ||
aee16b3c JF |
1793 | if (mm != &init_mm) |
1794 | pte_unmap_unlock(pte-1, ptl); | |
1795 | return err; | |
1796 | } | |
1797 | ||
1798 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1799 | unsigned long addr, unsigned long end, | |
1800 | pte_fn_t fn, void *data) | |
1801 | { | |
1802 | pmd_t *pmd; | |
1803 | unsigned long next; | |
1804 | int err; | |
1805 | ||
ceb86879 AK |
1806 | BUG_ON(pud_huge(*pud)); |
1807 | ||
aee16b3c JF |
1808 | pmd = pmd_alloc(mm, pud, addr); |
1809 | if (!pmd) | |
1810 | return -ENOMEM; | |
1811 | do { | |
1812 | next = pmd_addr_end(addr, end); | |
1813 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
1814 | if (err) | |
1815 | break; | |
1816 | } while (pmd++, addr = next, addr != end); | |
1817 | return err; | |
1818 | } | |
1819 | ||
1820 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1821 | unsigned long addr, unsigned long end, | |
1822 | pte_fn_t fn, void *data) | |
1823 | { | |
1824 | pud_t *pud; | |
1825 | unsigned long next; | |
1826 | int err; | |
1827 | ||
1828 | pud = pud_alloc(mm, pgd, addr); | |
1829 | if (!pud) | |
1830 | return -ENOMEM; | |
1831 | do { | |
1832 | next = pud_addr_end(addr, end); | |
1833 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
1834 | if (err) | |
1835 | break; | |
1836 | } while (pud++, addr = next, addr != end); | |
1837 | return err; | |
1838 | } | |
1839 | ||
1840 | /* | |
1841 | * Scan a region of virtual memory, filling in page tables as necessary | |
1842 | * and calling a provided function on each leaf page table. | |
1843 | */ | |
1844 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
1845 | unsigned long size, pte_fn_t fn, void *data) | |
1846 | { | |
1847 | pgd_t *pgd; | |
1848 | unsigned long next; | |
cddb8a5c | 1849 | unsigned long start = addr, end = addr + size; |
aee16b3c JF |
1850 | int err; |
1851 | ||
1852 | BUG_ON(addr >= end); | |
cddb8a5c | 1853 | mmu_notifier_invalidate_range_start(mm, start, end); |
aee16b3c JF |
1854 | pgd = pgd_offset(mm, addr); |
1855 | do { | |
1856 | next = pgd_addr_end(addr, end); | |
1857 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
1858 | if (err) | |
1859 | break; | |
1860 | } while (pgd++, addr = next, addr != end); | |
cddb8a5c | 1861 | mmu_notifier_invalidate_range_end(mm, start, end); |
aee16b3c JF |
1862 | return err; |
1863 | } | |
1864 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
1865 | ||
8f4e2101 HD |
1866 | /* |
1867 | * handle_pte_fault chooses page fault handler according to an entry | |
1868 | * which was read non-atomically. Before making any commitment, on | |
1869 | * those architectures or configurations (e.g. i386 with PAE) which | |
1870 | * might give a mix of unmatched parts, do_swap_page and do_file_page | |
1871 | * must check under lock before unmapping the pte and proceeding | |
1872 | * (but do_wp_page is only called after already making such a check; | |
1873 | * and do_anonymous_page and do_no_page can safely check later on). | |
1874 | */ | |
4c21e2f2 | 1875 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
1876 | pte_t *page_table, pte_t orig_pte) |
1877 | { | |
1878 | int same = 1; | |
1879 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
1880 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
1881 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
1882 | spin_lock(ptl); | |
8f4e2101 | 1883 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 1884 | spin_unlock(ptl); |
8f4e2101 HD |
1885 | } |
1886 | #endif | |
1887 | pte_unmap(page_table); | |
1888 | return same; | |
1889 | } | |
1890 | ||
1da177e4 LT |
1891 | /* |
1892 | * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when | |
1893 | * servicing faults for write access. In the normal case, do always want | |
1894 | * pte_mkwrite. But get_user_pages can cause write faults for mappings | |
1895 | * that do not have writing enabled, when used by access_process_vm. | |
1896 | */ | |
1897 | static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) | |
1898 | { | |
1899 | if (likely(vma->vm_flags & VM_WRITE)) | |
1900 | pte = pte_mkwrite(pte); | |
1901 | return pte; | |
1902 | } | |
1903 | ||
9de455b2 | 1904 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e LT |
1905 | { |
1906 | /* | |
1907 | * If the source page was a PFN mapping, we don't have | |
1908 | * a "struct page" for it. We do a best-effort copy by | |
1909 | * just copying from the original user address. If that | |
1910 | * fails, we just zero-fill it. Live with it. | |
1911 | */ | |
1912 | if (unlikely(!src)) { | |
1913 | void *kaddr = kmap_atomic(dst, KM_USER0); | |
5d2a2dbb LT |
1914 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
1915 | ||
1916 | /* | |
1917 | * This really shouldn't fail, because the page is there | |
1918 | * in the page tables. But it might just be unreadable, | |
1919 | * in which case we just give up and fill the result with | |
1920 | * zeroes. | |
1921 | */ | |
1922 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
6aab341e LT |
1923 | memset(kaddr, 0, PAGE_SIZE); |
1924 | kunmap_atomic(kaddr, KM_USER0); | |
c4ec7b0d | 1925 | flush_dcache_page(dst); |
0ed361de NP |
1926 | } else |
1927 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
1928 | } |
1929 | ||
1da177e4 LT |
1930 | /* |
1931 | * This routine handles present pages, when users try to write | |
1932 | * to a shared page. It is done by copying the page to a new address | |
1933 | * and decrementing the shared-page counter for the old page. | |
1934 | * | |
1da177e4 LT |
1935 | * Note that this routine assumes that the protection checks have been |
1936 | * done by the caller (the low-level page fault routine in most cases). | |
1937 | * Thus we can safely just mark it writable once we've done any necessary | |
1938 | * COW. | |
1939 | * | |
1940 | * We also mark the page dirty at this point even though the page will | |
1941 | * change only once the write actually happens. This avoids a few races, | |
1942 | * and potentially makes it more efficient. | |
1943 | * | |
8f4e2101 HD |
1944 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
1945 | * but allow concurrent faults), with pte both mapped and locked. | |
1946 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 1947 | */ |
65500d23 HD |
1948 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1949 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
8f4e2101 | 1950 | spinlock_t *ptl, pte_t orig_pte) |
1da177e4 | 1951 | { |
e5bbe4df | 1952 | struct page *old_page, *new_page; |
1da177e4 | 1953 | pte_t entry; |
83c54070 | 1954 | int reuse = 0, ret = 0; |
a200ee18 | 1955 | int page_mkwrite = 0; |
d08b3851 | 1956 | struct page *dirty_page = NULL; |
1da177e4 | 1957 | |
6aab341e | 1958 | old_page = vm_normal_page(vma, address, orig_pte); |
251b97f5 PZ |
1959 | if (!old_page) { |
1960 | /* | |
1961 | * VM_MIXEDMAP !pfn_valid() case | |
1962 | * | |
1963 | * We should not cow pages in a shared writeable mapping. | |
1964 | * Just mark the pages writable as we can't do any dirty | |
1965 | * accounting on raw pfn maps. | |
1966 | */ | |
1967 | if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
1968 | (VM_WRITE|VM_SHARED)) | |
1969 | goto reuse; | |
6aab341e | 1970 | goto gotten; |
251b97f5 | 1971 | } |
1da177e4 | 1972 | |
d08b3851 | 1973 | /* |
ee6a6457 PZ |
1974 | * Take out anonymous pages first, anonymous shared vmas are |
1975 | * not dirty accountable. | |
d08b3851 | 1976 | */ |
ee6a6457 | 1977 | if (PageAnon(old_page)) { |
ab967d86 HD |
1978 | if (!trylock_page(old_page)) { |
1979 | page_cache_get(old_page); | |
1980 | pte_unmap_unlock(page_table, ptl); | |
1981 | lock_page(old_page); | |
1982 | page_table = pte_offset_map_lock(mm, pmd, address, | |
1983 | &ptl); | |
1984 | if (!pte_same(*page_table, orig_pte)) { | |
1985 | unlock_page(old_page); | |
1986 | page_cache_release(old_page); | |
1987 | goto unlock; | |
1988 | } | |
1989 | page_cache_release(old_page); | |
ee6a6457 | 1990 | } |
7b1fe597 | 1991 | reuse = reuse_swap_page(old_page); |
ab967d86 | 1992 | unlock_page(old_page); |
ee6a6457 | 1993 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == |
d08b3851 | 1994 | (VM_WRITE|VM_SHARED))) { |
ee6a6457 PZ |
1995 | /* |
1996 | * Only catch write-faults on shared writable pages, | |
1997 | * read-only shared pages can get COWed by | |
1998 | * get_user_pages(.write=1, .force=1). | |
1999 | */ | |
9637a5ef | 2000 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
c2ec175c NP |
2001 | struct vm_fault vmf; |
2002 | int tmp; | |
2003 | ||
2004 | vmf.virtual_address = (void __user *)(address & | |
2005 | PAGE_MASK); | |
2006 | vmf.pgoff = old_page->index; | |
2007 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; | |
2008 | vmf.page = old_page; | |
2009 | ||
9637a5ef DH |
2010 | /* |
2011 | * Notify the address space that the page is about to | |
2012 | * become writable so that it can prohibit this or wait | |
2013 | * for the page to get into an appropriate state. | |
2014 | * | |
2015 | * We do this without the lock held, so that it can | |
2016 | * sleep if it needs to. | |
2017 | */ | |
2018 | page_cache_get(old_page); | |
2019 | pte_unmap_unlock(page_table, ptl); | |
2020 | ||
c2ec175c NP |
2021 | tmp = vma->vm_ops->page_mkwrite(vma, &vmf); |
2022 | if (unlikely(tmp & | |
2023 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { | |
2024 | ret = tmp; | |
9637a5ef | 2025 | goto unwritable_page; |
c2ec175c | 2026 | } |
b827e496 NP |
2027 | if (unlikely(!(tmp & VM_FAULT_LOCKED))) { |
2028 | lock_page(old_page); | |
2029 | if (!old_page->mapping) { | |
2030 | ret = 0; /* retry the fault */ | |
2031 | unlock_page(old_page); | |
2032 | goto unwritable_page; | |
2033 | } | |
2034 | } else | |
2035 | VM_BUG_ON(!PageLocked(old_page)); | |
9637a5ef | 2036 | |
9637a5ef DH |
2037 | /* |
2038 | * Since we dropped the lock we need to revalidate | |
2039 | * the PTE as someone else may have changed it. If | |
2040 | * they did, we just return, as we can count on the | |
2041 | * MMU to tell us if they didn't also make it writable. | |
2042 | */ | |
2043 | page_table = pte_offset_map_lock(mm, pmd, address, | |
2044 | &ptl); | |
b827e496 NP |
2045 | if (!pte_same(*page_table, orig_pte)) { |
2046 | unlock_page(old_page); | |
2047 | page_cache_release(old_page); | |
9637a5ef | 2048 | goto unlock; |
b827e496 | 2049 | } |
a200ee18 PZ |
2050 | |
2051 | page_mkwrite = 1; | |
1da177e4 | 2052 | } |
d08b3851 PZ |
2053 | dirty_page = old_page; |
2054 | get_page(dirty_page); | |
9637a5ef | 2055 | reuse = 1; |
9637a5ef DH |
2056 | } |
2057 | ||
2058 | if (reuse) { | |
251b97f5 | 2059 | reuse: |
9637a5ef DH |
2060 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
2061 | entry = pte_mkyoung(orig_pte); | |
2062 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
954ffcb3 | 2063 | if (ptep_set_access_flags(vma, address, page_table, entry,1)) |
8dab5241 | 2064 | update_mmu_cache(vma, address, entry); |
9637a5ef DH |
2065 | ret |= VM_FAULT_WRITE; |
2066 | goto unlock; | |
1da177e4 | 2067 | } |
1da177e4 LT |
2068 | |
2069 | /* | |
2070 | * Ok, we need to copy. Oh, well.. | |
2071 | */ | |
b5810039 | 2072 | page_cache_get(old_page); |
920fc356 | 2073 | gotten: |
8f4e2101 | 2074 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2075 | |
2076 | if (unlikely(anon_vma_prepare(vma))) | |
65500d23 | 2077 | goto oom; |
557ed1fa NP |
2078 | VM_BUG_ON(old_page == ZERO_PAGE(0)); |
2079 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
2080 | if (!new_page) | |
2081 | goto oom; | |
b291f000 NP |
2082 | /* |
2083 | * Don't let another task, with possibly unlocked vma, | |
2084 | * keep the mlocked page. | |
2085 | */ | |
ab92661d | 2086 | if ((vma->vm_flags & VM_LOCKED) && old_page) { |
b291f000 NP |
2087 | lock_page(old_page); /* for LRU manipulation */ |
2088 | clear_page_mlock(old_page); | |
2089 | unlock_page(old_page); | |
2090 | } | |
557ed1fa | 2091 | cow_user_page(new_page, old_page, address, vma); |
0ed361de | 2092 | __SetPageUptodate(new_page); |
65500d23 | 2093 | |
2c26fdd7 | 2094 | if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
2095 | goto oom_free_new; |
2096 | ||
1da177e4 LT |
2097 | /* |
2098 | * Re-check the pte - we dropped the lock | |
2099 | */ | |
8f4e2101 | 2100 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
65500d23 | 2101 | if (likely(pte_same(*page_table, orig_pte))) { |
920fc356 | 2102 | if (old_page) { |
920fc356 HD |
2103 | if (!PageAnon(old_page)) { |
2104 | dec_mm_counter(mm, file_rss); | |
2105 | inc_mm_counter(mm, anon_rss); | |
2106 | } | |
2107 | } else | |
4294621f | 2108 | inc_mm_counter(mm, anon_rss); |
eca35133 | 2109 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
65500d23 HD |
2110 | entry = mk_pte(new_page, vma->vm_page_prot); |
2111 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
4ce072f1 SS |
2112 | /* |
2113 | * Clear the pte entry and flush it first, before updating the | |
2114 | * pte with the new entry. This will avoid a race condition | |
2115 | * seen in the presence of one thread doing SMC and another | |
2116 | * thread doing COW. | |
2117 | */ | |
cddb8a5c | 2118 | ptep_clear_flush_notify(vma, address, page_table); |
9617d95e | 2119 | page_add_new_anon_rmap(new_page, vma, address); |
64d6519d LS |
2120 | set_pte_at(mm, address, page_table, entry); |
2121 | update_mmu_cache(vma, address, entry); | |
945754a1 NP |
2122 | if (old_page) { |
2123 | /* | |
2124 | * Only after switching the pte to the new page may | |
2125 | * we remove the mapcount here. Otherwise another | |
2126 | * process may come and find the rmap count decremented | |
2127 | * before the pte is switched to the new page, and | |
2128 | * "reuse" the old page writing into it while our pte | |
2129 | * here still points into it and can be read by other | |
2130 | * threads. | |
2131 | * | |
2132 | * The critical issue is to order this | |
2133 | * page_remove_rmap with the ptp_clear_flush above. | |
2134 | * Those stores are ordered by (if nothing else,) | |
2135 | * the barrier present in the atomic_add_negative | |
2136 | * in page_remove_rmap. | |
2137 | * | |
2138 | * Then the TLB flush in ptep_clear_flush ensures that | |
2139 | * no process can access the old page before the | |
2140 | * decremented mapcount is visible. And the old page | |
2141 | * cannot be reused until after the decremented | |
2142 | * mapcount is visible. So transitively, TLBs to | |
2143 | * old page will be flushed before it can be reused. | |
2144 | */ | |
edc315fd | 2145 | page_remove_rmap(old_page); |
945754a1 NP |
2146 | } |
2147 | ||
1da177e4 LT |
2148 | /* Free the old page.. */ |
2149 | new_page = old_page; | |
f33ea7f4 | 2150 | ret |= VM_FAULT_WRITE; |
8a9f3ccd BS |
2151 | } else |
2152 | mem_cgroup_uncharge_page(new_page); | |
2153 | ||
920fc356 HD |
2154 | if (new_page) |
2155 | page_cache_release(new_page); | |
2156 | if (old_page) | |
2157 | page_cache_release(old_page); | |
65500d23 | 2158 | unlock: |
8f4e2101 | 2159 | pte_unmap_unlock(page_table, ptl); |
d08b3851 | 2160 | if (dirty_page) { |
79352894 NP |
2161 | /* |
2162 | * Yes, Virginia, this is actually required to prevent a race | |
2163 | * with clear_page_dirty_for_io() from clearing the page dirty | |
2164 | * bit after it clear all dirty ptes, but before a racing | |
2165 | * do_wp_page installs a dirty pte. | |
2166 | * | |
2167 | * do_no_page is protected similarly. | |
2168 | */ | |
b827e496 NP |
2169 | if (!page_mkwrite) { |
2170 | wait_on_page_locked(dirty_page); | |
2171 | set_page_dirty_balance(dirty_page, page_mkwrite); | |
2172 | } | |
d08b3851 | 2173 | put_page(dirty_page); |
b827e496 NP |
2174 | if (page_mkwrite) { |
2175 | struct address_space *mapping = dirty_page->mapping; | |
2176 | ||
2177 | set_page_dirty(dirty_page); | |
2178 | unlock_page(dirty_page); | |
2179 | page_cache_release(dirty_page); | |
2180 | if (mapping) { | |
2181 | /* | |
2182 | * Some device drivers do not set page.mapping | |
2183 | * but still dirty their pages | |
2184 | */ | |
2185 | balance_dirty_pages_ratelimited(mapping); | |
2186 | } | |
2187 | } | |
2188 | ||
2189 | /* file_update_time outside page_lock */ | |
2190 | if (vma->vm_file) | |
2191 | file_update_time(vma->vm_file); | |
d08b3851 | 2192 | } |
f33ea7f4 | 2193 | return ret; |
8a9f3ccd | 2194 | oom_free_new: |
6dbf6d3b | 2195 | page_cache_release(new_page); |
65500d23 | 2196 | oom: |
b827e496 NP |
2197 | if (old_page) { |
2198 | if (page_mkwrite) { | |
2199 | unlock_page(old_page); | |
2200 | page_cache_release(old_page); | |
2201 | } | |
920fc356 | 2202 | page_cache_release(old_page); |
b827e496 | 2203 | } |
1da177e4 | 2204 | return VM_FAULT_OOM; |
9637a5ef DH |
2205 | |
2206 | unwritable_page: | |
2207 | page_cache_release(old_page); | |
c2ec175c | 2208 | return ret; |
1da177e4 LT |
2209 | } |
2210 | ||
2211 | /* | |
2212 | * Helper functions for unmap_mapping_range(). | |
2213 | * | |
2214 | * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ | |
2215 | * | |
2216 | * We have to restart searching the prio_tree whenever we drop the lock, | |
2217 | * since the iterator is only valid while the lock is held, and anyway | |
2218 | * a later vma might be split and reinserted earlier while lock dropped. | |
2219 | * | |
2220 | * The list of nonlinear vmas could be handled more efficiently, using | |
2221 | * a placeholder, but handle it in the same way until a need is shown. | |
2222 | * It is important to search the prio_tree before nonlinear list: a vma | |
2223 | * may become nonlinear and be shifted from prio_tree to nonlinear list | |
2224 | * while the lock is dropped; but never shifted from list to prio_tree. | |
2225 | * | |
2226 | * In order to make forward progress despite restarting the search, | |
2227 | * vm_truncate_count is used to mark a vma as now dealt with, so we can | |
2228 | * quickly skip it next time around. Since the prio_tree search only | |
2229 | * shows us those vmas affected by unmapping the range in question, we | |
2230 | * can't efficiently keep all vmas in step with mapping->truncate_count: | |
2231 | * so instead reset them all whenever it wraps back to 0 (then go to 1). | |
2232 | * mapping->truncate_count and vma->vm_truncate_count are protected by | |
2233 | * i_mmap_lock. | |
2234 | * | |
2235 | * In order to make forward progress despite repeatedly restarting some | |
ee39b37b | 2236 | * large vma, note the restart_addr from unmap_vmas when it breaks out: |
1da177e4 LT |
2237 | * and restart from that address when we reach that vma again. It might |
2238 | * have been split or merged, shrunk or extended, but never shifted: so | |
2239 | * restart_addr remains valid so long as it remains in the vma's range. | |
2240 | * unmap_mapping_range forces truncate_count to leap over page-aligned | |
2241 | * values so we can save vma's restart_addr in its truncate_count field. | |
2242 | */ | |
2243 | #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) | |
2244 | ||
2245 | static void reset_vma_truncate_counts(struct address_space *mapping) | |
2246 | { | |
2247 | struct vm_area_struct *vma; | |
2248 | struct prio_tree_iter iter; | |
2249 | ||
2250 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) | |
2251 | vma->vm_truncate_count = 0; | |
2252 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) | |
2253 | vma->vm_truncate_count = 0; | |
2254 | } | |
2255 | ||
2256 | static int unmap_mapping_range_vma(struct vm_area_struct *vma, | |
2257 | unsigned long start_addr, unsigned long end_addr, | |
2258 | struct zap_details *details) | |
2259 | { | |
2260 | unsigned long restart_addr; | |
2261 | int need_break; | |
2262 | ||
d00806b1 NP |
2263 | /* |
2264 | * files that support invalidating or truncating portions of the | |
d0217ac0 | 2265 | * file from under mmaped areas must have their ->fault function |
83c54070 NP |
2266 | * return a locked page (and set VM_FAULT_LOCKED in the return). |
2267 | * This provides synchronisation against concurrent unmapping here. | |
d00806b1 | 2268 | */ |
d00806b1 | 2269 | |
1da177e4 LT |
2270 | again: |
2271 | restart_addr = vma->vm_truncate_count; | |
2272 | if (is_restart_addr(restart_addr) && start_addr < restart_addr) { | |
2273 | start_addr = restart_addr; | |
2274 | if (start_addr >= end_addr) { | |
2275 | /* Top of vma has been split off since last time */ | |
2276 | vma->vm_truncate_count = details->truncate_count; | |
2277 | return 0; | |
2278 | } | |
2279 | } | |
2280 | ||
ee39b37b HD |
2281 | restart_addr = zap_page_range(vma, start_addr, |
2282 | end_addr - start_addr, details); | |
95c354fe | 2283 | need_break = need_resched() || spin_needbreak(details->i_mmap_lock); |
1da177e4 | 2284 | |
ee39b37b | 2285 | if (restart_addr >= end_addr) { |
1da177e4 LT |
2286 | /* We have now completed this vma: mark it so */ |
2287 | vma->vm_truncate_count = details->truncate_count; | |
2288 | if (!need_break) | |
2289 | return 0; | |
2290 | } else { | |
2291 | /* Note restart_addr in vma's truncate_count field */ | |
ee39b37b | 2292 | vma->vm_truncate_count = restart_addr; |
1da177e4 LT |
2293 | if (!need_break) |
2294 | goto again; | |
2295 | } | |
2296 | ||
2297 | spin_unlock(details->i_mmap_lock); | |
2298 | cond_resched(); | |
2299 | spin_lock(details->i_mmap_lock); | |
2300 | return -EINTR; | |
2301 | } | |
2302 | ||
2303 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, | |
2304 | struct zap_details *details) | |
2305 | { | |
2306 | struct vm_area_struct *vma; | |
2307 | struct prio_tree_iter iter; | |
2308 | pgoff_t vba, vea, zba, zea; | |
2309 | ||
2310 | restart: | |
2311 | vma_prio_tree_foreach(vma, &iter, root, | |
2312 | details->first_index, details->last_index) { | |
2313 | /* Skip quickly over those we have already dealt with */ | |
2314 | if (vma->vm_truncate_count == details->truncate_count) | |
2315 | continue; | |
2316 | ||
2317 | vba = vma->vm_pgoff; | |
2318 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; | |
2319 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ | |
2320 | zba = details->first_index; | |
2321 | if (zba < vba) | |
2322 | zba = vba; | |
2323 | zea = details->last_index; | |
2324 | if (zea > vea) | |
2325 | zea = vea; | |
2326 | ||
2327 | if (unmap_mapping_range_vma(vma, | |
2328 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, | |
2329 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
2330 | details) < 0) | |
2331 | goto restart; | |
2332 | } | |
2333 | } | |
2334 | ||
2335 | static inline void unmap_mapping_range_list(struct list_head *head, | |
2336 | struct zap_details *details) | |
2337 | { | |
2338 | struct vm_area_struct *vma; | |
2339 | ||
2340 | /* | |
2341 | * In nonlinear VMAs there is no correspondence between virtual address | |
2342 | * offset and file offset. So we must perform an exhaustive search | |
2343 | * across *all* the pages in each nonlinear VMA, not just the pages | |
2344 | * whose virtual address lies outside the file truncation point. | |
2345 | */ | |
2346 | restart: | |
2347 | list_for_each_entry(vma, head, shared.vm_set.list) { | |
2348 | /* Skip quickly over those we have already dealt with */ | |
2349 | if (vma->vm_truncate_count == details->truncate_count) | |
2350 | continue; | |
2351 | details->nonlinear_vma = vma; | |
2352 | if (unmap_mapping_range_vma(vma, vma->vm_start, | |
2353 | vma->vm_end, details) < 0) | |
2354 | goto restart; | |
2355 | } | |
2356 | } | |
2357 | ||
2358 | /** | |
72fd4a35 | 2359 | * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file. |
3d41088f | 2360 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
2361 | * @holebegin: byte in first page to unmap, relative to the start of |
2362 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
2363 | * boundary. Note that this is different from vmtruncate(), which | |
2364 | * must keep the partial page. In contrast, we must get rid of | |
2365 | * partial pages. | |
2366 | * @holelen: size of prospective hole in bytes. This will be rounded | |
2367 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
2368 | * end of the file. | |
2369 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
2370 | * but 0 when invalidating pagecache, don't throw away private data. | |
2371 | */ | |
2372 | void unmap_mapping_range(struct address_space *mapping, | |
2373 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
2374 | { | |
2375 | struct zap_details details; | |
2376 | pgoff_t hba = holebegin >> PAGE_SHIFT; | |
2377 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2378 | ||
2379 | /* Check for overflow. */ | |
2380 | if (sizeof(holelen) > sizeof(hlen)) { | |
2381 | long long holeend = | |
2382 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2383 | if (holeend & ~(long long)ULONG_MAX) | |
2384 | hlen = ULONG_MAX - hba + 1; | |
2385 | } | |
2386 | ||
2387 | details.check_mapping = even_cows? NULL: mapping; | |
2388 | details.nonlinear_vma = NULL; | |
2389 | details.first_index = hba; | |
2390 | details.last_index = hba + hlen - 1; | |
2391 | if (details.last_index < details.first_index) | |
2392 | details.last_index = ULONG_MAX; | |
2393 | details.i_mmap_lock = &mapping->i_mmap_lock; | |
2394 | ||
2395 | spin_lock(&mapping->i_mmap_lock); | |
2396 | ||
d00806b1 | 2397 | /* Protect against endless unmapping loops */ |
1da177e4 | 2398 | mapping->truncate_count++; |
1da177e4 LT |
2399 | if (unlikely(is_restart_addr(mapping->truncate_count))) { |
2400 | if (mapping->truncate_count == 0) | |
2401 | reset_vma_truncate_counts(mapping); | |
2402 | mapping->truncate_count++; | |
2403 | } | |
2404 | details.truncate_count = mapping->truncate_count; | |
2405 | ||
2406 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) | |
2407 | unmap_mapping_range_tree(&mapping->i_mmap, &details); | |
2408 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) | |
2409 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); | |
2410 | spin_unlock(&mapping->i_mmap_lock); | |
2411 | } | |
2412 | EXPORT_SYMBOL(unmap_mapping_range); | |
2413 | ||
bfa5bf6d REB |
2414 | /** |
2415 | * vmtruncate - unmap mappings "freed" by truncate() syscall | |
2416 | * @inode: inode of the file used | |
2417 | * @offset: file offset to start truncating | |
1da177e4 LT |
2418 | * |
2419 | * NOTE! We have to be ready to update the memory sharing | |
2420 | * between the file and the memory map for a potential last | |
2421 | * incomplete page. Ugly, but necessary. | |
2422 | */ | |
2423 | int vmtruncate(struct inode * inode, loff_t offset) | |
2424 | { | |
61d5048f CH |
2425 | if (inode->i_size < offset) { |
2426 | unsigned long limit; | |
2427 | ||
2428 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
2429 | if (limit != RLIM_INFINITY && offset > limit) | |
2430 | goto out_sig; | |
2431 | if (offset > inode->i_sb->s_maxbytes) | |
2432 | goto out_big; | |
2433 | i_size_write(inode, offset); | |
2434 | } else { | |
2435 | struct address_space *mapping = inode->i_mapping; | |
1da177e4 | 2436 | |
61d5048f CH |
2437 | /* |
2438 | * truncation of in-use swapfiles is disallowed - it would | |
2439 | * cause subsequent swapout to scribble on the now-freed | |
2440 | * blocks. | |
2441 | */ | |
2442 | if (IS_SWAPFILE(inode)) | |
2443 | return -ETXTBSY; | |
2444 | i_size_write(inode, offset); | |
2445 | ||
2446 | /* | |
2447 | * unmap_mapping_range is called twice, first simply for | |
2448 | * efficiency so that truncate_inode_pages does fewer | |
2449 | * single-page unmaps. However after this first call, and | |
2450 | * before truncate_inode_pages finishes, it is possible for | |
2451 | * private pages to be COWed, which remain after | |
2452 | * truncate_inode_pages finishes, hence the second | |
2453 | * unmap_mapping_range call must be made for correctness. | |
2454 | */ | |
2455 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
2456 | truncate_inode_pages(mapping, offset); | |
2457 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
2458 | } | |
d00806b1 | 2459 | |
acfa4380 | 2460 | if (inode->i_op->truncate) |
1da177e4 LT |
2461 | inode->i_op->truncate(inode); |
2462 | return 0; | |
61d5048f | 2463 | |
1da177e4 LT |
2464 | out_sig: |
2465 | send_sig(SIGXFSZ, current, 0); | |
2466 | out_big: | |
2467 | return -EFBIG; | |
1da177e4 | 2468 | } |
1da177e4 LT |
2469 | EXPORT_SYMBOL(vmtruncate); |
2470 | ||
f6b3ec23 BP |
2471 | int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) |
2472 | { | |
2473 | struct address_space *mapping = inode->i_mapping; | |
2474 | ||
2475 | /* | |
2476 | * If the underlying filesystem is not going to provide | |
2477 | * a way to truncate a range of blocks (punch a hole) - | |
2478 | * we should return failure right now. | |
2479 | */ | |
acfa4380 | 2480 | if (!inode->i_op->truncate_range) |
f6b3ec23 BP |
2481 | return -ENOSYS; |
2482 | ||
1b1dcc1b | 2483 | mutex_lock(&inode->i_mutex); |
f6b3ec23 BP |
2484 | down_write(&inode->i_alloc_sem); |
2485 | unmap_mapping_range(mapping, offset, (end - offset), 1); | |
2486 | truncate_inode_pages_range(mapping, offset, end); | |
d00806b1 | 2487 | unmap_mapping_range(mapping, offset, (end - offset), 1); |
f6b3ec23 BP |
2488 | inode->i_op->truncate_range(inode, offset, end); |
2489 | up_write(&inode->i_alloc_sem); | |
1b1dcc1b | 2490 | mutex_unlock(&inode->i_mutex); |
f6b3ec23 BP |
2491 | |
2492 | return 0; | |
2493 | } | |
f6b3ec23 | 2494 | |
1da177e4 | 2495 | /* |
8f4e2101 HD |
2496 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2497 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2498 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2499 | */ |
65500d23 HD |
2500 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2501 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 2502 | unsigned int flags, pte_t orig_pte) |
1da177e4 | 2503 | { |
8f4e2101 | 2504 | spinlock_t *ptl; |
1da177e4 | 2505 | struct page *page; |
65500d23 | 2506 | swp_entry_t entry; |
1da177e4 | 2507 | pte_t pte; |
7a81b88c | 2508 | struct mem_cgroup *ptr = NULL; |
83c54070 | 2509 | int ret = 0; |
1da177e4 | 2510 | |
4c21e2f2 | 2511 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
8f4e2101 | 2512 | goto out; |
65500d23 HD |
2513 | |
2514 | entry = pte_to_swp_entry(orig_pte); | |
0697212a CL |
2515 | if (is_migration_entry(entry)) { |
2516 | migration_entry_wait(mm, pmd, address); | |
2517 | goto out; | |
2518 | } | |
0ff92245 | 2519 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2520 | page = lookup_swap_cache(entry); |
2521 | if (!page) { | |
a5c9b696 | 2522 | grab_swap_token(mm); /* Contend for token _before_ read-in */ |
02098fea HD |
2523 | page = swapin_readahead(entry, |
2524 | GFP_HIGHUSER_MOVABLE, vma, address); | |
1da177e4 LT |
2525 | if (!page) { |
2526 | /* | |
8f4e2101 HD |
2527 | * Back out if somebody else faulted in this pte |
2528 | * while we released the pte lock. | |
1da177e4 | 2529 | */ |
8f4e2101 | 2530 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2531 | if (likely(pte_same(*page_table, orig_pte))) |
2532 | ret = VM_FAULT_OOM; | |
0ff92245 | 2533 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2534 | goto unlock; |
1da177e4 LT |
2535 | } |
2536 | ||
2537 | /* Had to read the page from swap area: Major fault */ | |
2538 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2539 | count_vm_event(PGMAJFAULT); |
1da177e4 LT |
2540 | } |
2541 | ||
073e587e KH |
2542 | lock_page(page); |
2543 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); | |
2544 | ||
2c26fdd7 | 2545 | if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) { |
8a9f3ccd | 2546 | ret = VM_FAULT_OOM; |
bc43f75c | 2547 | goto out_page; |
8a9f3ccd BS |
2548 | } |
2549 | ||
1da177e4 | 2550 | /* |
8f4e2101 | 2551 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 2552 | */ |
8f4e2101 | 2553 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
9e9bef07 | 2554 | if (unlikely(!pte_same(*page_table, orig_pte))) |
b8107480 | 2555 | goto out_nomap; |
b8107480 KK |
2556 | |
2557 | if (unlikely(!PageUptodate(page))) { | |
2558 | ret = VM_FAULT_SIGBUS; | |
2559 | goto out_nomap; | |
1da177e4 LT |
2560 | } |
2561 | ||
8c7c6e34 KH |
2562 | /* |
2563 | * The page isn't present yet, go ahead with the fault. | |
2564 | * | |
2565 | * Be careful about the sequence of operations here. | |
2566 | * To get its accounting right, reuse_swap_page() must be called | |
2567 | * while the page is counted on swap but not yet in mapcount i.e. | |
2568 | * before page_add_anon_rmap() and swap_free(); try_to_free_swap() | |
2569 | * must be called after the swap_free(), or it will never succeed. | |
03f3c433 KH |
2570 | * Because delete_from_swap_page() may be called by reuse_swap_page(), |
2571 | * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry | |
2572 | * in page->private. In this case, a record in swap_cgroup is silently | |
2573 | * discarded at swap_free(). | |
8c7c6e34 | 2574 | */ |
1da177e4 | 2575 | |
4294621f | 2576 | inc_mm_counter(mm, anon_rss); |
1da177e4 | 2577 | pte = mk_pte(page, vma->vm_page_prot); |
30c9f3a9 | 2578 | if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) { |
1da177e4 | 2579 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); |
30c9f3a9 | 2580 | flags &= ~FAULT_FLAG_WRITE; |
1da177e4 | 2581 | } |
1da177e4 LT |
2582 | flush_icache_page(vma, page); |
2583 | set_pte_at(mm, address, page_table, pte); | |
2584 | page_add_anon_rmap(page, vma, address); | |
03f3c433 KH |
2585 | /* It's better to call commit-charge after rmap is established */ |
2586 | mem_cgroup_commit_charge_swapin(page, ptr); | |
1da177e4 | 2587 | |
c475a8ab | 2588 | swap_free(entry); |
b291f000 | 2589 | if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) |
a2c43eed | 2590 | try_to_free_swap(page); |
c475a8ab HD |
2591 | unlock_page(page); |
2592 | ||
30c9f3a9 | 2593 | if (flags & FAULT_FLAG_WRITE) { |
61469f1d HD |
2594 | ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); |
2595 | if (ret & VM_FAULT_ERROR) | |
2596 | ret &= VM_FAULT_ERROR; | |
1da177e4 LT |
2597 | goto out; |
2598 | } | |
2599 | ||
2600 | /* No need to invalidate - it was non-present before */ | |
2601 | update_mmu_cache(vma, address, pte); | |
65500d23 | 2602 | unlock: |
8f4e2101 | 2603 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2604 | out: |
2605 | return ret; | |
b8107480 | 2606 | out_nomap: |
7a81b88c | 2607 | mem_cgroup_cancel_charge_swapin(ptr); |
8f4e2101 | 2608 | pte_unmap_unlock(page_table, ptl); |
bc43f75c | 2609 | out_page: |
b8107480 KK |
2610 | unlock_page(page); |
2611 | page_cache_release(page); | |
65500d23 | 2612 | return ret; |
1da177e4 LT |
2613 | } |
2614 | ||
2615 | /* | |
8f4e2101 HD |
2616 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2617 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2618 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2619 | */ |
65500d23 HD |
2620 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2621 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 2622 | unsigned int flags) |
1da177e4 | 2623 | { |
8f4e2101 HD |
2624 | struct page *page; |
2625 | spinlock_t *ptl; | |
1da177e4 | 2626 | pte_t entry; |
1da177e4 | 2627 | |
557ed1fa NP |
2628 | /* Allocate our own private page. */ |
2629 | pte_unmap(page_table); | |
8f4e2101 | 2630 | |
557ed1fa NP |
2631 | if (unlikely(anon_vma_prepare(vma))) |
2632 | goto oom; | |
2633 | page = alloc_zeroed_user_highpage_movable(vma, address); | |
2634 | if (!page) | |
2635 | goto oom; | |
0ed361de | 2636 | __SetPageUptodate(page); |
8f4e2101 | 2637 | |
2c26fdd7 | 2638 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
2639 | goto oom_free_page; |
2640 | ||
557ed1fa NP |
2641 | entry = mk_pte(page, vma->vm_page_prot); |
2642 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1da177e4 | 2643 | |
557ed1fa NP |
2644 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
2645 | if (!pte_none(*page_table)) | |
2646 | goto release; | |
2647 | inc_mm_counter(mm, anon_rss); | |
557ed1fa | 2648 | page_add_new_anon_rmap(page, vma, address); |
65500d23 | 2649 | set_pte_at(mm, address, page_table, entry); |
1da177e4 LT |
2650 | |
2651 | /* No need to invalidate - it was non-present before */ | |
65500d23 | 2652 | update_mmu_cache(vma, address, entry); |
65500d23 | 2653 | unlock: |
8f4e2101 | 2654 | pte_unmap_unlock(page_table, ptl); |
83c54070 | 2655 | return 0; |
8f4e2101 | 2656 | release: |
8a9f3ccd | 2657 | mem_cgroup_uncharge_page(page); |
8f4e2101 HD |
2658 | page_cache_release(page); |
2659 | goto unlock; | |
8a9f3ccd | 2660 | oom_free_page: |
6dbf6d3b | 2661 | page_cache_release(page); |
65500d23 | 2662 | oom: |
1da177e4 LT |
2663 | return VM_FAULT_OOM; |
2664 | } | |
2665 | ||
2666 | /* | |
54cb8821 | 2667 | * __do_fault() tries to create a new page mapping. It aggressively |
1da177e4 | 2668 | * tries to share with existing pages, but makes a separate copy if |
54cb8821 NP |
2669 | * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid |
2670 | * the next page fault. | |
1da177e4 LT |
2671 | * |
2672 | * As this is called only for pages that do not currently exist, we | |
2673 | * do not need to flush old virtual caches or the TLB. | |
2674 | * | |
8f4e2101 | 2675 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
16abfa08 | 2676 | * but allow concurrent faults), and pte neither mapped nor locked. |
8f4e2101 | 2677 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
1da177e4 | 2678 | */ |
54cb8821 | 2679 | static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
16abfa08 | 2680 | unsigned long address, pmd_t *pmd, |
54cb8821 | 2681 | pgoff_t pgoff, unsigned int flags, pte_t orig_pte) |
1da177e4 | 2682 | { |
16abfa08 | 2683 | pte_t *page_table; |
8f4e2101 | 2684 | spinlock_t *ptl; |
d0217ac0 | 2685 | struct page *page; |
1da177e4 | 2686 | pte_t entry; |
1da177e4 | 2687 | int anon = 0; |
5b4e655e | 2688 | int charged = 0; |
d08b3851 | 2689 | struct page *dirty_page = NULL; |
d0217ac0 NP |
2690 | struct vm_fault vmf; |
2691 | int ret; | |
a200ee18 | 2692 | int page_mkwrite = 0; |
54cb8821 | 2693 | |
d0217ac0 NP |
2694 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); |
2695 | vmf.pgoff = pgoff; | |
2696 | vmf.flags = flags; | |
2697 | vmf.page = NULL; | |
1da177e4 | 2698 | |
3c18ddd1 NP |
2699 | ret = vma->vm_ops->fault(vma, &vmf); |
2700 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) | |
2701 | return ret; | |
1da177e4 | 2702 | |
d00806b1 | 2703 | /* |
d0217ac0 | 2704 | * For consistency in subsequent calls, make the faulted page always |
d00806b1 NP |
2705 | * locked. |
2706 | */ | |
83c54070 | 2707 | if (unlikely(!(ret & VM_FAULT_LOCKED))) |
d0217ac0 | 2708 | lock_page(vmf.page); |
54cb8821 | 2709 | else |
d0217ac0 | 2710 | VM_BUG_ON(!PageLocked(vmf.page)); |
d00806b1 | 2711 | |
1da177e4 LT |
2712 | /* |
2713 | * Should we do an early C-O-W break? | |
2714 | */ | |
d0217ac0 | 2715 | page = vmf.page; |
54cb8821 | 2716 | if (flags & FAULT_FLAG_WRITE) { |
9637a5ef | 2717 | if (!(vma->vm_flags & VM_SHARED)) { |
54cb8821 | 2718 | anon = 1; |
d00806b1 | 2719 | if (unlikely(anon_vma_prepare(vma))) { |
d0217ac0 | 2720 | ret = VM_FAULT_OOM; |
54cb8821 | 2721 | goto out; |
d00806b1 | 2722 | } |
83c54070 NP |
2723 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, |
2724 | vma, address); | |
d00806b1 | 2725 | if (!page) { |
d0217ac0 | 2726 | ret = VM_FAULT_OOM; |
54cb8821 | 2727 | goto out; |
d00806b1 | 2728 | } |
2c26fdd7 | 2729 | if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) { |
5b4e655e KH |
2730 | ret = VM_FAULT_OOM; |
2731 | page_cache_release(page); | |
2732 | goto out; | |
2733 | } | |
2734 | charged = 1; | |
b291f000 NP |
2735 | /* |
2736 | * Don't let another task, with possibly unlocked vma, | |
2737 | * keep the mlocked page. | |
2738 | */ | |
2739 | if (vma->vm_flags & VM_LOCKED) | |
2740 | clear_page_mlock(vmf.page); | |
d0217ac0 | 2741 | copy_user_highpage(page, vmf.page, address, vma); |
0ed361de | 2742 | __SetPageUptodate(page); |
9637a5ef | 2743 | } else { |
54cb8821 NP |
2744 | /* |
2745 | * If the page will be shareable, see if the backing | |
9637a5ef | 2746 | * address space wants to know that the page is about |
54cb8821 NP |
2747 | * to become writable |
2748 | */ | |
69676147 | 2749 | if (vma->vm_ops->page_mkwrite) { |
c2ec175c NP |
2750 | int tmp; |
2751 | ||
69676147 | 2752 | unlock_page(page); |
b827e496 | 2753 | vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE; |
c2ec175c NP |
2754 | tmp = vma->vm_ops->page_mkwrite(vma, &vmf); |
2755 | if (unlikely(tmp & | |
2756 | (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) { | |
2757 | ret = tmp; | |
b827e496 | 2758 | goto unwritable_page; |
d0217ac0 | 2759 | } |
b827e496 NP |
2760 | if (unlikely(!(tmp & VM_FAULT_LOCKED))) { |
2761 | lock_page(page); | |
2762 | if (!page->mapping) { | |
2763 | ret = 0; /* retry the fault */ | |
2764 | unlock_page(page); | |
2765 | goto unwritable_page; | |
2766 | } | |
2767 | } else | |
2768 | VM_BUG_ON(!PageLocked(page)); | |
a200ee18 | 2769 | page_mkwrite = 1; |
9637a5ef DH |
2770 | } |
2771 | } | |
54cb8821 | 2772 | |
1da177e4 LT |
2773 | } |
2774 | ||
8f4e2101 | 2775 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2776 | |
2777 | /* | |
2778 | * This silly early PAGE_DIRTY setting removes a race | |
2779 | * due to the bad i386 page protection. But it's valid | |
2780 | * for other architectures too. | |
2781 | * | |
30c9f3a9 | 2782 | * Note that if FAULT_FLAG_WRITE is set, we either now have |
1da177e4 LT |
2783 | * an exclusive copy of the page, or this is a shared mapping, |
2784 | * so we can make it writable and dirty to avoid having to | |
2785 | * handle that later. | |
2786 | */ | |
2787 | /* Only go through if we didn't race with anybody else... */ | |
54cb8821 | 2788 | if (likely(pte_same(*page_table, orig_pte))) { |
d00806b1 NP |
2789 | flush_icache_page(vma, page); |
2790 | entry = mk_pte(page, vma->vm_page_prot); | |
54cb8821 | 2791 | if (flags & FAULT_FLAG_WRITE) |
1da177e4 | 2792 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
1da177e4 | 2793 | if (anon) { |
64d6519d | 2794 | inc_mm_counter(mm, anon_rss); |
64d6519d | 2795 | page_add_new_anon_rmap(page, vma, address); |
f57e88a8 | 2796 | } else { |
4294621f | 2797 | inc_mm_counter(mm, file_rss); |
d00806b1 | 2798 | page_add_file_rmap(page); |
54cb8821 | 2799 | if (flags & FAULT_FLAG_WRITE) { |
d00806b1 | 2800 | dirty_page = page; |
d08b3851 PZ |
2801 | get_page(dirty_page); |
2802 | } | |
4294621f | 2803 | } |
64d6519d | 2804 | set_pte_at(mm, address, page_table, entry); |
d00806b1 NP |
2805 | |
2806 | /* no need to invalidate: a not-present page won't be cached */ | |
2807 | update_mmu_cache(vma, address, entry); | |
1da177e4 | 2808 | } else { |
5b4e655e KH |
2809 | if (charged) |
2810 | mem_cgroup_uncharge_page(page); | |
d00806b1 NP |
2811 | if (anon) |
2812 | page_cache_release(page); | |
2813 | else | |
54cb8821 | 2814 | anon = 1; /* no anon but release faulted_page */ |
1da177e4 LT |
2815 | } |
2816 | ||
8f4e2101 | 2817 | pte_unmap_unlock(page_table, ptl); |
d00806b1 NP |
2818 | |
2819 | out: | |
b827e496 NP |
2820 | if (dirty_page) { |
2821 | struct address_space *mapping = page->mapping; | |
8f7b3d15 | 2822 | |
b827e496 NP |
2823 | if (set_page_dirty(dirty_page)) |
2824 | page_mkwrite = 1; | |
2825 | unlock_page(dirty_page); | |
d08b3851 | 2826 | put_page(dirty_page); |
b827e496 NP |
2827 | if (page_mkwrite && mapping) { |
2828 | /* | |
2829 | * Some device drivers do not set page.mapping but still | |
2830 | * dirty their pages | |
2831 | */ | |
2832 | balance_dirty_pages_ratelimited(mapping); | |
2833 | } | |
2834 | ||
2835 | /* file_update_time outside page_lock */ | |
2836 | if (vma->vm_file) | |
2837 | file_update_time(vma->vm_file); | |
2838 | } else { | |
2839 | unlock_page(vmf.page); | |
2840 | if (anon) | |
2841 | page_cache_release(vmf.page); | |
d08b3851 | 2842 | } |
d00806b1 | 2843 | |
83c54070 | 2844 | return ret; |
b827e496 NP |
2845 | |
2846 | unwritable_page: | |
2847 | page_cache_release(page); | |
2848 | return ret; | |
54cb8821 | 2849 | } |
d00806b1 | 2850 | |
54cb8821 NP |
2851 | static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
2852 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
30c9f3a9 | 2853 | unsigned int flags, pte_t orig_pte) |
54cb8821 NP |
2854 | { |
2855 | pgoff_t pgoff = (((address & PAGE_MASK) | |
0da7e01f | 2856 | - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
54cb8821 | 2857 | |
16abfa08 HD |
2858 | pte_unmap(page_table); |
2859 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); | |
54cb8821 NP |
2860 | } |
2861 | ||
1da177e4 LT |
2862 | /* |
2863 | * Fault of a previously existing named mapping. Repopulate the pte | |
2864 | * from the encoded file_pte if possible. This enables swappable | |
2865 | * nonlinear vmas. | |
8f4e2101 HD |
2866 | * |
2867 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
2868 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2869 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2870 | */ |
d0217ac0 | 2871 | static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
65500d23 | 2872 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
30c9f3a9 | 2873 | unsigned int flags, pte_t orig_pte) |
1da177e4 | 2874 | { |
65500d23 | 2875 | pgoff_t pgoff; |
1da177e4 | 2876 | |
30c9f3a9 LT |
2877 | flags |= FAULT_FLAG_NONLINEAR; |
2878 | ||
4c21e2f2 | 2879 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
83c54070 | 2880 | return 0; |
1da177e4 | 2881 | |
2509ef26 | 2882 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) { |
65500d23 HD |
2883 | /* |
2884 | * Page table corrupted: show pte and kill process. | |
2885 | */ | |
3dc14741 | 2886 | print_bad_pte(vma, address, orig_pte, NULL); |
65500d23 HD |
2887 | return VM_FAULT_OOM; |
2888 | } | |
65500d23 HD |
2889 | |
2890 | pgoff = pte_to_pgoff(orig_pte); | |
16abfa08 | 2891 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); |
1da177e4 LT |
2892 | } |
2893 | ||
2894 | /* | |
2895 | * These routines also need to handle stuff like marking pages dirty | |
2896 | * and/or accessed for architectures that don't do it in hardware (most | |
2897 | * RISC architectures). The early dirtying is also good on the i386. | |
2898 | * | |
2899 | * There is also a hook called "update_mmu_cache()" that architectures | |
2900 | * with external mmu caches can use to update those (ie the Sparc or | |
2901 | * PowerPC hashed page tables that act as extended TLBs). | |
2902 | * | |
c74df32c HD |
2903 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2904 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2905 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 LT |
2906 | */ |
2907 | static inline int handle_pte_fault(struct mm_struct *mm, | |
65500d23 | 2908 | struct vm_area_struct *vma, unsigned long address, |
30c9f3a9 | 2909 | pte_t *pte, pmd_t *pmd, unsigned int flags) |
1da177e4 LT |
2910 | { |
2911 | pte_t entry; | |
8f4e2101 | 2912 | spinlock_t *ptl; |
1da177e4 | 2913 | |
8dab5241 | 2914 | entry = *pte; |
1da177e4 | 2915 | if (!pte_present(entry)) { |
65500d23 | 2916 | if (pte_none(entry)) { |
f4b81804 | 2917 | if (vma->vm_ops) { |
3c18ddd1 | 2918 | if (likely(vma->vm_ops->fault)) |
54cb8821 | 2919 | return do_linear_fault(mm, vma, address, |
30c9f3a9 | 2920 | pte, pmd, flags, entry); |
f4b81804 JS |
2921 | } |
2922 | return do_anonymous_page(mm, vma, address, | |
30c9f3a9 | 2923 | pte, pmd, flags); |
65500d23 | 2924 | } |
1da177e4 | 2925 | if (pte_file(entry)) |
d0217ac0 | 2926 | return do_nonlinear_fault(mm, vma, address, |
30c9f3a9 | 2927 | pte, pmd, flags, entry); |
65500d23 | 2928 | return do_swap_page(mm, vma, address, |
30c9f3a9 | 2929 | pte, pmd, flags, entry); |
1da177e4 LT |
2930 | } |
2931 | ||
4c21e2f2 | 2932 | ptl = pte_lockptr(mm, pmd); |
8f4e2101 HD |
2933 | spin_lock(ptl); |
2934 | if (unlikely(!pte_same(*pte, entry))) | |
2935 | goto unlock; | |
30c9f3a9 | 2936 | if (flags & FAULT_FLAG_WRITE) { |
1da177e4 | 2937 | if (!pte_write(entry)) |
8f4e2101 HD |
2938 | return do_wp_page(mm, vma, address, |
2939 | pte, pmd, ptl, entry); | |
1da177e4 LT |
2940 | entry = pte_mkdirty(entry); |
2941 | } | |
2942 | entry = pte_mkyoung(entry); | |
30c9f3a9 | 2943 | if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) { |
1a44e149 | 2944 | update_mmu_cache(vma, address, entry); |
1a44e149 AA |
2945 | } else { |
2946 | /* | |
2947 | * This is needed only for protection faults but the arch code | |
2948 | * is not yet telling us if this is a protection fault or not. | |
2949 | * This still avoids useless tlb flushes for .text page faults | |
2950 | * with threads. | |
2951 | */ | |
30c9f3a9 | 2952 | if (flags & FAULT_FLAG_WRITE) |
1a44e149 AA |
2953 | flush_tlb_page(vma, address); |
2954 | } | |
8f4e2101 HD |
2955 | unlock: |
2956 | pte_unmap_unlock(pte, ptl); | |
83c54070 | 2957 | return 0; |
1da177e4 LT |
2958 | } |
2959 | ||
2960 | /* | |
2961 | * By the time we get here, we already hold the mm semaphore | |
2962 | */ | |
83c54070 | 2963 | int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
d06063cc | 2964 | unsigned long address, unsigned int flags) |
1da177e4 LT |
2965 | { |
2966 | pgd_t *pgd; | |
2967 | pud_t *pud; | |
2968 | pmd_t *pmd; | |
2969 | pte_t *pte; | |
2970 | ||
2971 | __set_current_state(TASK_RUNNING); | |
2972 | ||
f8891e5e | 2973 | count_vm_event(PGFAULT); |
1da177e4 | 2974 | |
ac9b9c66 | 2975 | if (unlikely(is_vm_hugetlb_page(vma))) |
30c9f3a9 | 2976 | return hugetlb_fault(mm, vma, address, flags); |
1da177e4 | 2977 | |
1da177e4 | 2978 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
2979 | pud = pud_alloc(mm, pgd, address); |
2980 | if (!pud) | |
c74df32c | 2981 | return VM_FAULT_OOM; |
1da177e4 LT |
2982 | pmd = pmd_alloc(mm, pud, address); |
2983 | if (!pmd) | |
c74df32c | 2984 | return VM_FAULT_OOM; |
1da177e4 LT |
2985 | pte = pte_alloc_map(mm, pmd, address); |
2986 | if (!pte) | |
c74df32c | 2987 | return VM_FAULT_OOM; |
1da177e4 | 2988 | |
30c9f3a9 | 2989 | return handle_pte_fault(mm, vma, address, pte, pmd, flags); |
1da177e4 LT |
2990 | } |
2991 | ||
2992 | #ifndef __PAGETABLE_PUD_FOLDED | |
2993 | /* | |
2994 | * Allocate page upper directory. | |
872fec16 | 2995 | * We've already handled the fast-path in-line. |
1da177e4 | 2996 | */ |
1bb3630e | 2997 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 2998 | { |
c74df32c HD |
2999 | pud_t *new = pud_alloc_one(mm, address); |
3000 | if (!new) | |
1bb3630e | 3001 | return -ENOMEM; |
1da177e4 | 3002 | |
362a61ad NP |
3003 | smp_wmb(); /* See comment in __pte_alloc */ |
3004 | ||
872fec16 | 3005 | spin_lock(&mm->page_table_lock); |
1bb3630e | 3006 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 3007 | pud_free(mm, new); |
1bb3630e HD |
3008 | else |
3009 | pgd_populate(mm, pgd, new); | |
c74df32c | 3010 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3011 | return 0; |
1da177e4 LT |
3012 | } |
3013 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
3014 | ||
3015 | #ifndef __PAGETABLE_PMD_FOLDED | |
3016 | /* | |
3017 | * Allocate page middle directory. | |
872fec16 | 3018 | * We've already handled the fast-path in-line. |
1da177e4 | 3019 | */ |
1bb3630e | 3020 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 3021 | { |
c74df32c HD |
3022 | pmd_t *new = pmd_alloc_one(mm, address); |
3023 | if (!new) | |
1bb3630e | 3024 | return -ENOMEM; |
1da177e4 | 3025 | |
362a61ad NP |
3026 | smp_wmb(); /* See comment in __pte_alloc */ |
3027 | ||
872fec16 | 3028 | spin_lock(&mm->page_table_lock); |
1da177e4 | 3029 | #ifndef __ARCH_HAS_4LEVEL_HACK |
1bb3630e | 3030 | if (pud_present(*pud)) /* Another has populated it */ |
5e541973 | 3031 | pmd_free(mm, new); |
1bb3630e HD |
3032 | else |
3033 | pud_populate(mm, pud, new); | |
1da177e4 | 3034 | #else |
1bb3630e | 3035 | if (pgd_present(*pud)) /* Another has populated it */ |
5e541973 | 3036 | pmd_free(mm, new); |
1bb3630e HD |
3037 | else |
3038 | pgd_populate(mm, pud, new); | |
1da177e4 | 3039 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 3040 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 3041 | return 0; |
e0f39591 | 3042 | } |
1da177e4 LT |
3043 | #endif /* __PAGETABLE_PMD_FOLDED */ |
3044 | ||
3045 | int make_pages_present(unsigned long addr, unsigned long end) | |
3046 | { | |
3047 | int ret, len, write; | |
3048 | struct vm_area_struct * vma; | |
3049 | ||
3050 | vma = find_vma(current->mm, addr); | |
3051 | if (!vma) | |
a477097d | 3052 | return -ENOMEM; |
1da177e4 | 3053 | write = (vma->vm_flags & VM_WRITE) != 0; |
5bcb28b1 ES |
3054 | BUG_ON(addr >= end); |
3055 | BUG_ON(end > vma->vm_end); | |
68e116a3 | 3056 | len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; |
1da177e4 LT |
3057 | ret = get_user_pages(current, current->mm, addr, |
3058 | len, write, 0, NULL, NULL); | |
c11d69d8 | 3059 | if (ret < 0) |
1da177e4 | 3060 | return ret; |
9978ad58 | 3061 | return ret == len ? 0 : -EFAULT; |
1da177e4 LT |
3062 | } |
3063 | ||
1da177e4 LT |
3064 | #if !defined(__HAVE_ARCH_GATE_AREA) |
3065 | ||
3066 | #if defined(AT_SYSINFO_EHDR) | |
5ce7852c | 3067 | static struct vm_area_struct gate_vma; |
1da177e4 LT |
3068 | |
3069 | static int __init gate_vma_init(void) | |
3070 | { | |
3071 | gate_vma.vm_mm = NULL; | |
3072 | gate_vma.vm_start = FIXADDR_USER_START; | |
3073 | gate_vma.vm_end = FIXADDR_USER_END; | |
b6558c4a RM |
3074 | gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; |
3075 | gate_vma.vm_page_prot = __P101; | |
f47aef55 RM |
3076 | /* |
3077 | * Make sure the vDSO gets into every core dump. | |
3078 | * Dumping its contents makes post-mortem fully interpretable later | |
3079 | * without matching up the same kernel and hardware config to see | |
3080 | * what PC values meant. | |
3081 | */ | |
3082 | gate_vma.vm_flags |= VM_ALWAYSDUMP; | |
1da177e4 LT |
3083 | return 0; |
3084 | } | |
3085 | __initcall(gate_vma_init); | |
3086 | #endif | |
3087 | ||
3088 | struct vm_area_struct *get_gate_vma(struct task_struct *tsk) | |
3089 | { | |
3090 | #ifdef AT_SYSINFO_EHDR | |
3091 | return &gate_vma; | |
3092 | #else | |
3093 | return NULL; | |
3094 | #endif | |
3095 | } | |
3096 | ||
3097 | int in_gate_area_no_task(unsigned long addr) | |
3098 | { | |
3099 | #ifdef AT_SYSINFO_EHDR | |
3100 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) | |
3101 | return 1; | |
3102 | #endif | |
3103 | return 0; | |
3104 | } | |
3105 | ||
3106 | #endif /* __HAVE_ARCH_GATE_AREA */ | |
0ec76a11 | 3107 | |
f8ad0f49 JW |
3108 | static int follow_pte(struct mm_struct *mm, unsigned long address, |
3109 | pte_t **ptepp, spinlock_t **ptlp) | |
3110 | { | |
3111 | pgd_t *pgd; | |
3112 | pud_t *pud; | |
3113 | pmd_t *pmd; | |
3114 | pte_t *ptep; | |
3115 | ||
3116 | pgd = pgd_offset(mm, address); | |
3117 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
3118 | goto out; | |
3119 | ||
3120 | pud = pud_offset(pgd, address); | |
3121 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
3122 | goto out; | |
3123 | ||
3124 | pmd = pmd_offset(pud, address); | |
3125 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
3126 | goto out; | |
3127 | ||
3128 | /* We cannot handle huge page PFN maps. Luckily they don't exist. */ | |
3129 | if (pmd_huge(*pmd)) | |
3130 | goto out; | |
3131 | ||
3132 | ptep = pte_offset_map_lock(mm, pmd, address, ptlp); | |
3133 | if (!ptep) | |
3134 | goto out; | |
3135 | if (!pte_present(*ptep)) | |
3136 | goto unlock; | |
3137 | *ptepp = ptep; | |
3138 | return 0; | |
3139 | unlock: | |
3140 | pte_unmap_unlock(ptep, *ptlp); | |
3141 | out: | |
3142 | return -EINVAL; | |
3143 | } | |
3144 | ||
3b6748e2 JW |
3145 | /** |
3146 | * follow_pfn - look up PFN at a user virtual address | |
3147 | * @vma: memory mapping | |
3148 | * @address: user virtual address | |
3149 | * @pfn: location to store found PFN | |
3150 | * | |
3151 | * Only IO mappings and raw PFN mappings are allowed. | |
3152 | * | |
3153 | * Returns zero and the pfn at @pfn on success, -ve otherwise. | |
3154 | */ | |
3155 | int follow_pfn(struct vm_area_struct *vma, unsigned long address, | |
3156 | unsigned long *pfn) | |
3157 | { | |
3158 | int ret = -EINVAL; | |
3159 | spinlock_t *ptl; | |
3160 | pte_t *ptep; | |
3161 | ||
3162 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
3163 | return ret; | |
3164 | ||
3165 | ret = follow_pte(vma->vm_mm, address, &ptep, &ptl); | |
3166 | if (ret) | |
3167 | return ret; | |
3168 | *pfn = pte_pfn(*ptep); | |
3169 | pte_unmap_unlock(ptep, ptl); | |
3170 | return 0; | |
3171 | } | |
3172 | EXPORT_SYMBOL(follow_pfn); | |
3173 | ||
28b2ee20 | 3174 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
d87fe660 | 3175 | int follow_phys(struct vm_area_struct *vma, |
3176 | unsigned long address, unsigned int flags, | |
3177 | unsigned long *prot, resource_size_t *phys) | |
28b2ee20 | 3178 | { |
03668a4d | 3179 | int ret = -EINVAL; |
28b2ee20 RR |
3180 | pte_t *ptep, pte; |
3181 | spinlock_t *ptl; | |
28b2ee20 | 3182 | |
d87fe660 | 3183 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) |
3184 | goto out; | |
28b2ee20 | 3185 | |
03668a4d | 3186 | if (follow_pte(vma->vm_mm, address, &ptep, &ptl)) |
d87fe660 | 3187 | goto out; |
28b2ee20 | 3188 | pte = *ptep; |
03668a4d | 3189 | |
28b2ee20 RR |
3190 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
3191 | goto unlock; | |
28b2ee20 RR |
3192 | |
3193 | *prot = pgprot_val(pte_pgprot(pte)); | |
03668a4d | 3194 | *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT; |
28b2ee20 | 3195 | |
03668a4d | 3196 | ret = 0; |
28b2ee20 RR |
3197 | unlock: |
3198 | pte_unmap_unlock(ptep, ptl); | |
3199 | out: | |
d87fe660 | 3200 | return ret; |
28b2ee20 RR |
3201 | } |
3202 | ||
3203 | int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, | |
3204 | void *buf, int len, int write) | |
3205 | { | |
3206 | resource_size_t phys_addr; | |
3207 | unsigned long prot = 0; | |
2bc7273b | 3208 | void __iomem *maddr; |
28b2ee20 RR |
3209 | int offset = addr & (PAGE_SIZE-1); |
3210 | ||
d87fe660 | 3211 | if (follow_phys(vma, addr, write, &prot, &phys_addr)) |
28b2ee20 RR |
3212 | return -EINVAL; |
3213 | ||
3214 | maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); | |
3215 | if (write) | |
3216 | memcpy_toio(maddr + offset, buf, len); | |
3217 | else | |
3218 | memcpy_fromio(buf, maddr + offset, len); | |
3219 | iounmap(maddr); | |
3220 | ||
3221 | return len; | |
3222 | } | |
3223 | #endif | |
3224 | ||
0ec76a11 DH |
3225 | /* |
3226 | * Access another process' address space. | |
3227 | * Source/target buffer must be kernel space, | |
3228 | * Do not walk the page table directly, use get_user_pages | |
3229 | */ | |
3230 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
3231 | { | |
3232 | struct mm_struct *mm; | |
3233 | struct vm_area_struct *vma; | |
0ec76a11 DH |
3234 | void *old_buf = buf; |
3235 | ||
3236 | mm = get_task_mm(tsk); | |
3237 | if (!mm) | |
3238 | return 0; | |
3239 | ||
3240 | down_read(&mm->mmap_sem); | |
183ff22b | 3241 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
3242 | while (len) { |
3243 | int bytes, ret, offset; | |
3244 | void *maddr; | |
28b2ee20 | 3245 | struct page *page = NULL; |
0ec76a11 DH |
3246 | |
3247 | ret = get_user_pages(tsk, mm, addr, 1, | |
3248 | write, 1, &page, &vma); | |
28b2ee20 RR |
3249 | if (ret <= 0) { |
3250 | /* | |
3251 | * Check if this is a VM_IO | VM_PFNMAP VMA, which | |
3252 | * we can access using slightly different code. | |
3253 | */ | |
3254 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
3255 | vma = find_vma(mm, addr); | |
3256 | if (!vma) | |
3257 | break; | |
3258 | if (vma->vm_ops && vma->vm_ops->access) | |
3259 | ret = vma->vm_ops->access(vma, addr, buf, | |
3260 | len, write); | |
3261 | if (ret <= 0) | |
3262 | #endif | |
3263 | break; | |
3264 | bytes = ret; | |
0ec76a11 | 3265 | } else { |
28b2ee20 RR |
3266 | bytes = len; |
3267 | offset = addr & (PAGE_SIZE-1); | |
3268 | if (bytes > PAGE_SIZE-offset) | |
3269 | bytes = PAGE_SIZE-offset; | |
3270 | ||
3271 | maddr = kmap(page); | |
3272 | if (write) { | |
3273 | copy_to_user_page(vma, page, addr, | |
3274 | maddr + offset, buf, bytes); | |
3275 | set_page_dirty_lock(page); | |
3276 | } else { | |
3277 | copy_from_user_page(vma, page, addr, | |
3278 | buf, maddr + offset, bytes); | |
3279 | } | |
3280 | kunmap(page); | |
3281 | page_cache_release(page); | |
0ec76a11 | 3282 | } |
0ec76a11 DH |
3283 | len -= bytes; |
3284 | buf += bytes; | |
3285 | addr += bytes; | |
3286 | } | |
3287 | up_read(&mm->mmap_sem); | |
3288 | mmput(mm); | |
3289 | ||
3290 | return buf - old_buf; | |
3291 | } | |
03252919 AK |
3292 | |
3293 | /* | |
3294 | * Print the name of a VMA. | |
3295 | */ | |
3296 | void print_vma_addr(char *prefix, unsigned long ip) | |
3297 | { | |
3298 | struct mm_struct *mm = current->mm; | |
3299 | struct vm_area_struct *vma; | |
3300 | ||
e8bff74a IM |
3301 | /* |
3302 | * Do not print if we are in atomic | |
3303 | * contexts (in exception stacks, etc.): | |
3304 | */ | |
3305 | if (preempt_count()) | |
3306 | return; | |
3307 | ||
03252919 AK |
3308 | down_read(&mm->mmap_sem); |
3309 | vma = find_vma(mm, ip); | |
3310 | if (vma && vma->vm_file) { | |
3311 | struct file *f = vma->vm_file; | |
3312 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
3313 | if (buf) { | |
3314 | char *p, *s; | |
3315 | ||
cf28b486 | 3316 | p = d_path(&f->f_path, buf, PAGE_SIZE); |
03252919 AK |
3317 | if (IS_ERR(p)) |
3318 | p = "?"; | |
3319 | s = strrchr(p, '/'); | |
3320 | if (s) | |
3321 | p = s+1; | |
3322 | printk("%s%s[%lx+%lx]", prefix, p, | |
3323 | vma->vm_start, | |
3324 | vma->vm_end - vma->vm_start); | |
3325 | free_page((unsigned long)buf); | |
3326 | } | |
3327 | } | |
3328 | up_read(¤t->mm->mmap_sem); | |
3329 | } | |
3ee1afa3 NP |
3330 | |
3331 | #ifdef CONFIG_PROVE_LOCKING | |
3332 | void might_fault(void) | |
3333 | { | |
95156f00 PZ |
3334 | /* |
3335 | * Some code (nfs/sunrpc) uses socket ops on kernel memory while | |
3336 | * holding the mmap_sem, this is safe because kernel memory doesn't | |
3337 | * get paged out, therefore we'll never actually fault, and the | |
3338 | * below annotations will generate false positives. | |
3339 | */ | |
3340 | if (segment_eq(get_fs(), KERNEL_DS)) | |
3341 | return; | |
3342 | ||
3ee1afa3 NP |
3343 | might_sleep(); |
3344 | /* | |
3345 | * it would be nicer only to annotate paths which are not under | |
3346 | * pagefault_disable, however that requires a larger audit and | |
3347 | * providing helpers like get_user_atomic. | |
3348 | */ | |
3349 | if (!in_atomic() && current->mm) | |
3350 | might_lock_read(¤t->mm->mmap_sem); | |
3351 | } | |
3352 | EXPORT_SYMBOL(might_fault); | |
3353 | #endif |