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> |
1da177e4 LT |
54 | |
55 | #include <asm/pgalloc.h> | |
56 | #include <asm/uaccess.h> | |
57 | #include <asm/tlb.h> | |
58 | #include <asm/tlbflush.h> | |
59 | #include <asm/pgtable.h> | |
60 | ||
61 | #include <linux/swapops.h> | |
62 | #include <linux/elf.h> | |
63 | ||
42b77728 JB |
64 | #include "internal.h" |
65 | ||
d41dee36 | 66 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
67 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
68 | unsigned long max_mapnr; | |
69 | struct page *mem_map; | |
70 | ||
71 | EXPORT_SYMBOL(max_mapnr); | |
72 | EXPORT_SYMBOL(mem_map); | |
73 | #endif | |
74 | ||
75 | unsigned long num_physpages; | |
76 | /* | |
77 | * A number of key systems in x86 including ioremap() rely on the assumption | |
78 | * that high_memory defines the upper bound on direct map memory, then end | |
79 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and | |
80 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL | |
81 | * and ZONE_HIGHMEM. | |
82 | */ | |
83 | void * high_memory; | |
1da177e4 LT |
84 | |
85 | EXPORT_SYMBOL(num_physpages); | |
86 | EXPORT_SYMBOL(high_memory); | |
1da177e4 | 87 | |
32a93233 IM |
88 | /* |
89 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
90 | * | |
91 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
92 | * as ancient (libc5 based) binaries can segfault. ) | |
93 | */ | |
94 | int randomize_va_space __read_mostly = | |
95 | #ifdef CONFIG_COMPAT_BRK | |
96 | 1; | |
97 | #else | |
98 | 2; | |
99 | #endif | |
a62eaf15 AK |
100 | |
101 | static int __init disable_randmaps(char *s) | |
102 | { | |
103 | randomize_va_space = 0; | |
9b41046c | 104 | return 1; |
a62eaf15 AK |
105 | } |
106 | __setup("norandmaps", disable_randmaps); | |
107 | ||
108 | ||
1da177e4 LT |
109 | /* |
110 | * If a p?d_bad entry is found while walking page tables, report | |
111 | * the error, before resetting entry to p?d_none. Usually (but | |
112 | * very seldom) called out from the p?d_none_or_clear_bad macros. | |
113 | */ | |
114 | ||
115 | void pgd_clear_bad(pgd_t *pgd) | |
116 | { | |
117 | pgd_ERROR(*pgd); | |
118 | pgd_clear(pgd); | |
119 | } | |
120 | ||
121 | void pud_clear_bad(pud_t *pud) | |
122 | { | |
123 | pud_ERROR(*pud); | |
124 | pud_clear(pud); | |
125 | } | |
126 | ||
127 | void pmd_clear_bad(pmd_t *pmd) | |
128 | { | |
129 | pmd_ERROR(*pmd); | |
130 | pmd_clear(pmd); | |
131 | } | |
132 | ||
133 | /* | |
134 | * Note: this doesn't free the actual pages themselves. That | |
135 | * has been handled earlier when unmapping all the memory regions. | |
136 | */ | |
e0da382c | 137 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) |
1da177e4 | 138 | { |
2f569afd | 139 | pgtable_t token = pmd_pgtable(*pmd); |
e0da382c | 140 | pmd_clear(pmd); |
2f569afd | 141 | pte_free_tlb(tlb, token); |
e0da382c | 142 | tlb->mm->nr_ptes--; |
1da177e4 LT |
143 | } |
144 | ||
e0da382c HD |
145 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
146 | unsigned long addr, unsigned long end, | |
147 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
148 | { |
149 | pmd_t *pmd; | |
150 | unsigned long next; | |
e0da382c | 151 | unsigned long start; |
1da177e4 | 152 | |
e0da382c | 153 | start = addr; |
1da177e4 | 154 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
155 | do { |
156 | next = pmd_addr_end(addr, end); | |
157 | if (pmd_none_or_clear_bad(pmd)) | |
158 | continue; | |
e0da382c | 159 | free_pte_range(tlb, pmd); |
1da177e4 LT |
160 | } while (pmd++, addr = next, addr != end); |
161 | ||
e0da382c HD |
162 | start &= PUD_MASK; |
163 | if (start < floor) | |
164 | return; | |
165 | if (ceiling) { | |
166 | ceiling &= PUD_MASK; | |
167 | if (!ceiling) | |
168 | return; | |
1da177e4 | 169 | } |
e0da382c HD |
170 | if (end - 1 > ceiling - 1) |
171 | return; | |
172 | ||
173 | pmd = pmd_offset(pud, start); | |
174 | pud_clear(pud); | |
175 | pmd_free_tlb(tlb, pmd); | |
1da177e4 LT |
176 | } |
177 | ||
e0da382c HD |
178 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
179 | unsigned long addr, unsigned long end, | |
180 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
181 | { |
182 | pud_t *pud; | |
183 | unsigned long next; | |
e0da382c | 184 | unsigned long start; |
1da177e4 | 185 | |
e0da382c | 186 | start = addr; |
1da177e4 | 187 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
188 | do { |
189 | next = pud_addr_end(addr, end); | |
190 | if (pud_none_or_clear_bad(pud)) | |
191 | continue; | |
e0da382c | 192 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
193 | } while (pud++, addr = next, addr != end); |
194 | ||
e0da382c HD |
195 | start &= PGDIR_MASK; |
196 | if (start < floor) | |
197 | return; | |
198 | if (ceiling) { | |
199 | ceiling &= PGDIR_MASK; | |
200 | if (!ceiling) | |
201 | return; | |
1da177e4 | 202 | } |
e0da382c HD |
203 | if (end - 1 > ceiling - 1) |
204 | return; | |
205 | ||
206 | pud = pud_offset(pgd, start); | |
207 | pgd_clear(pgd); | |
208 | pud_free_tlb(tlb, pud); | |
1da177e4 LT |
209 | } |
210 | ||
211 | /* | |
e0da382c HD |
212 | * This function frees user-level page tables of a process. |
213 | * | |
1da177e4 LT |
214 | * Must be called with pagetable lock held. |
215 | */ | |
42b77728 | 216 | void free_pgd_range(struct mmu_gather *tlb, |
e0da382c HD |
217 | unsigned long addr, unsigned long end, |
218 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
219 | { |
220 | pgd_t *pgd; | |
221 | unsigned long next; | |
e0da382c HD |
222 | unsigned long start; |
223 | ||
224 | /* | |
225 | * The next few lines have given us lots of grief... | |
226 | * | |
227 | * Why are we testing PMD* at this top level? Because often | |
228 | * there will be no work to do at all, and we'd prefer not to | |
229 | * go all the way down to the bottom just to discover that. | |
230 | * | |
231 | * Why all these "- 1"s? Because 0 represents both the bottom | |
232 | * of the address space and the top of it (using -1 for the | |
233 | * top wouldn't help much: the masks would do the wrong thing). | |
234 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
235 | * the address space, but end 0 and ceiling 0 refer to the top | |
236 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
237 | * that end 0 case should be mythical). | |
238 | * | |
239 | * Wherever addr is brought up or ceiling brought down, we must | |
240 | * be careful to reject "the opposite 0" before it confuses the | |
241 | * subsequent tests. But what about where end is brought down | |
242 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
243 | * | |
244 | * Whereas we round start (addr) and ceiling down, by different | |
245 | * masks at different levels, in order to test whether a table | |
246 | * now has no other vmas using it, so can be freed, we don't | |
247 | * bother to round floor or end up - the tests don't need that. | |
248 | */ | |
1da177e4 | 249 | |
e0da382c HD |
250 | addr &= PMD_MASK; |
251 | if (addr < floor) { | |
252 | addr += PMD_SIZE; | |
253 | if (!addr) | |
254 | return; | |
255 | } | |
256 | if (ceiling) { | |
257 | ceiling &= PMD_MASK; | |
258 | if (!ceiling) | |
259 | return; | |
260 | } | |
261 | if (end - 1 > ceiling - 1) | |
262 | end -= PMD_SIZE; | |
263 | if (addr > end - 1) | |
264 | return; | |
265 | ||
266 | start = addr; | |
42b77728 | 267 | pgd = pgd_offset(tlb->mm, addr); |
1da177e4 LT |
268 | do { |
269 | next = pgd_addr_end(addr, end); | |
270 | if (pgd_none_or_clear_bad(pgd)) | |
271 | continue; | |
42b77728 | 272 | free_pud_range(tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 273 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
274 | } |
275 | ||
42b77728 | 276 | void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3bf5ee95 | 277 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
278 | { |
279 | while (vma) { | |
280 | struct vm_area_struct *next = vma->vm_next; | |
281 | unsigned long addr = vma->vm_start; | |
282 | ||
8f4f8c16 HD |
283 | /* |
284 | * Hide vma from rmap and vmtruncate before freeing pgtables | |
285 | */ | |
286 | anon_vma_unlink(vma); | |
287 | unlink_file_vma(vma); | |
288 | ||
9da61aef | 289 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 290 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 291 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
292 | } else { |
293 | /* | |
294 | * Optimization: gather nearby vmas into one call down | |
295 | */ | |
296 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 297 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
298 | vma = next; |
299 | next = vma->vm_next; | |
8f4f8c16 HD |
300 | anon_vma_unlink(vma); |
301 | unlink_file_vma(vma); | |
3bf5ee95 HD |
302 | } |
303 | free_pgd_range(tlb, addr, vma->vm_end, | |
304 | floor, next? next->vm_start: ceiling); | |
305 | } | |
e0da382c HD |
306 | vma = next; |
307 | } | |
1da177e4 LT |
308 | } |
309 | ||
1bb3630e | 310 | int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
1da177e4 | 311 | { |
2f569afd | 312 | pgtable_t new = pte_alloc_one(mm, address); |
1bb3630e HD |
313 | if (!new) |
314 | return -ENOMEM; | |
315 | ||
362a61ad NP |
316 | /* |
317 | * Ensure all pte setup (eg. pte page lock and page clearing) are | |
318 | * visible before the pte is made visible to other CPUs by being | |
319 | * put into page tables. | |
320 | * | |
321 | * The other side of the story is the pointer chasing in the page | |
322 | * table walking code (when walking the page table without locking; | |
323 | * ie. most of the time). Fortunately, these data accesses consist | |
324 | * of a chain of data-dependent loads, meaning most CPUs (alpha | |
325 | * being the notable exception) will already guarantee loads are | |
326 | * seen in-order. See the alpha page table accessors for the | |
327 | * smp_read_barrier_depends() barriers in page table walking code. | |
328 | */ | |
329 | smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ | |
330 | ||
c74df32c | 331 | spin_lock(&mm->page_table_lock); |
2f569afd | 332 | if (!pmd_present(*pmd)) { /* Has another populated it ? */ |
1da177e4 | 333 | mm->nr_ptes++; |
1da177e4 | 334 | pmd_populate(mm, pmd, new); |
2f569afd | 335 | new = NULL; |
1da177e4 | 336 | } |
c74df32c | 337 | spin_unlock(&mm->page_table_lock); |
2f569afd MS |
338 | if (new) |
339 | pte_free(mm, new); | |
1bb3630e | 340 | return 0; |
1da177e4 LT |
341 | } |
342 | ||
1bb3630e | 343 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 344 | { |
1bb3630e HD |
345 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
346 | if (!new) | |
347 | return -ENOMEM; | |
348 | ||
362a61ad NP |
349 | smp_wmb(); /* See comment in __pte_alloc */ |
350 | ||
1bb3630e | 351 | spin_lock(&init_mm.page_table_lock); |
2f569afd | 352 | if (!pmd_present(*pmd)) { /* Has another populated it ? */ |
1bb3630e | 353 | pmd_populate_kernel(&init_mm, pmd, new); |
2f569afd MS |
354 | new = NULL; |
355 | } | |
1bb3630e | 356 | spin_unlock(&init_mm.page_table_lock); |
2f569afd MS |
357 | if (new) |
358 | pte_free_kernel(&init_mm, new); | |
1bb3630e | 359 | return 0; |
1da177e4 LT |
360 | } |
361 | ||
ae859762 HD |
362 | static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) |
363 | { | |
364 | if (file_rss) | |
365 | add_mm_counter(mm, file_rss, file_rss); | |
366 | if (anon_rss) | |
367 | add_mm_counter(mm, anon_rss, anon_rss); | |
368 | } | |
369 | ||
b5810039 | 370 | /* |
6aab341e LT |
371 | * This function is called to print an error when a bad pte |
372 | * is found. For example, we might have a PFN-mapped pte in | |
373 | * a region that doesn't allow it. | |
b5810039 NP |
374 | * |
375 | * The calling function must still handle the error. | |
376 | */ | |
377 | void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr) | |
378 | { | |
379 | printk(KERN_ERR "Bad pte = %08llx, process = %s, " | |
380 | "vm_flags = %lx, vaddr = %lx\n", | |
381 | (long long)pte_val(pte), | |
382 | (vma->vm_mm == current->mm ? current->comm : "???"), | |
383 | vma->vm_flags, vaddr); | |
384 | dump_stack(); | |
385 | } | |
386 | ||
67121172 LT |
387 | static inline int is_cow_mapping(unsigned int flags) |
388 | { | |
389 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
390 | } | |
391 | ||
ee498ed7 | 392 | /* |
7e675137 | 393 | * vm_normal_page -- This function gets the "struct page" associated with a pte. |
6aab341e | 394 | * |
7e675137 NP |
395 | * "Special" mappings do not wish to be associated with a "struct page" (either |
396 | * it doesn't exist, or it exists but they don't want to touch it). In this | |
397 | * case, NULL is returned here. "Normal" mappings do have a struct page. | |
b379d790 | 398 | * |
7e675137 NP |
399 | * There are 2 broad cases. Firstly, an architecture may define a pte_special() |
400 | * pte bit, in which case this function is trivial. Secondly, an architecture | |
401 | * may not have a spare pte bit, which requires a more complicated scheme, | |
402 | * described below. | |
403 | * | |
404 | * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a | |
405 | * special mapping (even if there are underlying and valid "struct pages"). | |
406 | * COWed pages of a VM_PFNMAP are always normal. | |
6aab341e | 407 | * |
b379d790 JH |
408 | * The way we recognize COWed pages within VM_PFNMAP mappings is through the |
409 | * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit | |
7e675137 NP |
410 | * set, and the vm_pgoff will point to the first PFN mapped: thus every special |
411 | * mapping will always honor the rule | |
6aab341e LT |
412 | * |
413 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
414 | * | |
7e675137 NP |
415 | * And for normal mappings this is false. |
416 | * | |
417 | * This restricts such mappings to be a linear translation from virtual address | |
418 | * to pfn. To get around this restriction, we allow arbitrary mappings so long | |
419 | * as the vma is not a COW mapping; in that case, we know that all ptes are | |
420 | * special (because none can have been COWed). | |
b379d790 | 421 | * |
b379d790 | 422 | * |
7e675137 | 423 | * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. |
b379d790 JH |
424 | * |
425 | * VM_MIXEDMAP mappings can likewise contain memory with or without "struct | |
426 | * page" backing, however the difference is that _all_ pages with a struct | |
427 | * page (that is, those where pfn_valid is true) are refcounted and considered | |
428 | * normal pages by the VM. The disadvantage is that pages are refcounted | |
429 | * (which can be slower and simply not an option for some PFNMAP users). The | |
430 | * advantage is that we don't have to follow the strict linearity rule of | |
431 | * PFNMAP mappings in order to support COWable mappings. | |
432 | * | |
ee498ed7 | 433 | */ |
7e675137 NP |
434 | #ifdef __HAVE_ARCH_PTE_SPECIAL |
435 | # define HAVE_PTE_SPECIAL 1 | |
436 | #else | |
437 | # define HAVE_PTE_SPECIAL 0 | |
438 | #endif | |
439 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, | |
440 | pte_t pte) | |
ee498ed7 | 441 | { |
7e675137 NP |
442 | unsigned long pfn; |
443 | ||
444 | if (HAVE_PTE_SPECIAL) { | |
445 | if (likely(!pte_special(pte))) { | |
446 | VM_BUG_ON(!pfn_valid(pte_pfn(pte))); | |
447 | return pte_page(pte); | |
448 | } | |
449 | VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))); | |
450 | return NULL; | |
451 | } | |
452 | ||
453 | /* !HAVE_PTE_SPECIAL case follows: */ | |
454 | ||
455 | pfn = pte_pfn(pte); | |
6aab341e | 456 | |
b379d790 JH |
457 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { |
458 | if (vma->vm_flags & VM_MIXEDMAP) { | |
459 | if (!pfn_valid(pfn)) | |
460 | return NULL; | |
461 | goto out; | |
462 | } else { | |
7e675137 NP |
463 | unsigned long off; |
464 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
b379d790 JH |
465 | if (pfn == vma->vm_pgoff + off) |
466 | return NULL; | |
467 | if (!is_cow_mapping(vma->vm_flags)) | |
468 | return NULL; | |
469 | } | |
6aab341e LT |
470 | } |
471 | ||
7e675137 | 472 | VM_BUG_ON(!pfn_valid(pfn)); |
6aab341e LT |
473 | |
474 | /* | |
7e675137 | 475 | * NOTE! We still have PageReserved() pages in the page tables. |
6aab341e | 476 | * |
7e675137 | 477 | * eg. VDSO mappings can cause them to exist. |
6aab341e | 478 | */ |
b379d790 | 479 | out: |
6aab341e | 480 | return pfn_to_page(pfn); |
ee498ed7 HD |
481 | } |
482 | ||
1da177e4 LT |
483 | /* |
484 | * copy one vm_area from one task to the other. Assumes the page tables | |
485 | * already present in the new task to be cleared in the whole range | |
486 | * covered by this vma. | |
1da177e4 LT |
487 | */ |
488 | ||
8c103762 | 489 | static inline void |
1da177e4 | 490 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 491 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 492 | unsigned long addr, int *rss) |
1da177e4 | 493 | { |
b5810039 | 494 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
495 | pte_t pte = *src_pte; |
496 | struct page *page; | |
1da177e4 LT |
497 | |
498 | /* pte contains position in swap or file, so copy. */ | |
499 | if (unlikely(!pte_present(pte))) { | |
500 | if (!pte_file(pte)) { | |
0697212a CL |
501 | swp_entry_t entry = pte_to_swp_entry(pte); |
502 | ||
503 | swap_duplicate(entry); | |
1da177e4 LT |
504 | /* make sure dst_mm is on swapoff's mmlist. */ |
505 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
506 | spin_lock(&mmlist_lock); | |
f412ac08 HD |
507 | if (list_empty(&dst_mm->mmlist)) |
508 | list_add(&dst_mm->mmlist, | |
509 | &src_mm->mmlist); | |
1da177e4 LT |
510 | spin_unlock(&mmlist_lock); |
511 | } | |
0697212a CL |
512 | if (is_write_migration_entry(entry) && |
513 | is_cow_mapping(vm_flags)) { | |
514 | /* | |
515 | * COW mappings require pages in both parent | |
516 | * and child to be set to read. | |
517 | */ | |
518 | make_migration_entry_read(&entry); | |
519 | pte = swp_entry_to_pte(entry); | |
520 | set_pte_at(src_mm, addr, src_pte, pte); | |
521 | } | |
1da177e4 | 522 | } |
ae859762 | 523 | goto out_set_pte; |
1da177e4 LT |
524 | } |
525 | ||
1da177e4 LT |
526 | /* |
527 | * If it's a COW mapping, write protect it both | |
528 | * in the parent and the child | |
529 | */ | |
67121172 | 530 | if (is_cow_mapping(vm_flags)) { |
1da177e4 | 531 | ptep_set_wrprotect(src_mm, addr, src_pte); |
3dc90795 | 532 | pte = pte_wrprotect(pte); |
1da177e4 LT |
533 | } |
534 | ||
535 | /* | |
536 | * If it's a shared mapping, mark it clean in | |
537 | * the child | |
538 | */ | |
539 | if (vm_flags & VM_SHARED) | |
540 | pte = pte_mkclean(pte); | |
541 | pte = pte_mkold(pte); | |
6aab341e LT |
542 | |
543 | page = vm_normal_page(vma, addr, pte); | |
544 | if (page) { | |
545 | get_page(page); | |
c97a9e10 | 546 | page_dup_rmap(page, vma, addr); |
6aab341e LT |
547 | rss[!!PageAnon(page)]++; |
548 | } | |
ae859762 HD |
549 | |
550 | out_set_pte: | |
551 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
1da177e4 LT |
552 | } |
553 | ||
554 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
555 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, | |
556 | unsigned long addr, unsigned long end) | |
557 | { | |
558 | pte_t *src_pte, *dst_pte; | |
c74df32c | 559 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 560 | int progress = 0; |
8c103762 | 561 | int rss[2]; |
1da177e4 LT |
562 | |
563 | again: | |
ae859762 | 564 | rss[1] = rss[0] = 0; |
c74df32c | 565 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
566 | if (!dst_pte) |
567 | return -ENOMEM; | |
568 | src_pte = pte_offset_map_nested(src_pmd, addr); | |
4c21e2f2 | 569 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 570 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
6606c3e0 | 571 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 572 | |
1da177e4 LT |
573 | do { |
574 | /* | |
575 | * We are holding two locks at this point - either of them | |
576 | * could generate latencies in another task on another CPU. | |
577 | */ | |
e040f218 HD |
578 | if (progress >= 32) { |
579 | progress = 0; | |
580 | if (need_resched() || | |
95c354fe | 581 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
582 | break; |
583 | } | |
1da177e4 LT |
584 | if (pte_none(*src_pte)) { |
585 | progress++; | |
586 | continue; | |
587 | } | |
8c103762 | 588 | copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); |
1da177e4 LT |
589 | progress += 8; |
590 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 591 | |
6606c3e0 | 592 | arch_leave_lazy_mmu_mode(); |
c74df32c | 593 | spin_unlock(src_ptl); |
1da177e4 | 594 | pte_unmap_nested(src_pte - 1); |
ae859762 | 595 | add_mm_rss(dst_mm, rss[0], rss[1]); |
c74df32c HD |
596 | pte_unmap_unlock(dst_pte - 1, dst_ptl); |
597 | cond_resched(); | |
1da177e4 LT |
598 | if (addr != end) |
599 | goto again; | |
600 | return 0; | |
601 | } | |
602 | ||
603 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
604 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
605 | unsigned long addr, unsigned long end) | |
606 | { | |
607 | pmd_t *src_pmd, *dst_pmd; | |
608 | unsigned long next; | |
609 | ||
610 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
611 | if (!dst_pmd) | |
612 | return -ENOMEM; | |
613 | src_pmd = pmd_offset(src_pud, addr); | |
614 | do { | |
615 | next = pmd_addr_end(addr, end); | |
616 | if (pmd_none_or_clear_bad(src_pmd)) | |
617 | continue; | |
618 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
619 | vma, addr, next)) | |
620 | return -ENOMEM; | |
621 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
622 | return 0; | |
623 | } | |
624 | ||
625 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
626 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
627 | unsigned long addr, unsigned long end) | |
628 | { | |
629 | pud_t *src_pud, *dst_pud; | |
630 | unsigned long next; | |
631 | ||
632 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
633 | if (!dst_pud) | |
634 | return -ENOMEM; | |
635 | src_pud = pud_offset(src_pgd, addr); | |
636 | do { | |
637 | next = pud_addr_end(addr, end); | |
638 | if (pud_none_or_clear_bad(src_pud)) | |
639 | continue; | |
640 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
641 | vma, addr, next)) | |
642 | return -ENOMEM; | |
643 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
644 | return 0; | |
645 | } | |
646 | ||
647 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
648 | struct vm_area_struct *vma) | |
649 | { | |
650 | pgd_t *src_pgd, *dst_pgd; | |
651 | unsigned long next; | |
652 | unsigned long addr = vma->vm_start; | |
653 | unsigned long end = vma->vm_end; | |
654 | ||
d992895b NP |
655 | /* |
656 | * Don't copy ptes where a page fault will fill them correctly. | |
657 | * Fork becomes much lighter when there are big shared or private | |
658 | * readonly mappings. The tradeoff is that copy_page_range is more | |
659 | * efficient than faulting. | |
660 | */ | |
4d7672b4 | 661 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { |
d992895b NP |
662 | if (!vma->anon_vma) |
663 | return 0; | |
664 | } | |
665 | ||
1da177e4 LT |
666 | if (is_vm_hugetlb_page(vma)) |
667 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
668 | ||
669 | dst_pgd = pgd_offset(dst_mm, addr); | |
670 | src_pgd = pgd_offset(src_mm, addr); | |
671 | do { | |
672 | next = pgd_addr_end(addr, end); | |
673 | if (pgd_none_or_clear_bad(src_pgd)) | |
674 | continue; | |
675 | if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, | |
676 | vma, addr, next)) | |
677 | return -ENOMEM; | |
678 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); | |
679 | return 0; | |
680 | } | |
681 | ||
51c6f666 | 682 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 683 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 684 | unsigned long addr, unsigned long end, |
51c6f666 | 685 | long *zap_work, struct zap_details *details) |
1da177e4 | 686 | { |
b5810039 | 687 | struct mm_struct *mm = tlb->mm; |
1da177e4 | 688 | pte_t *pte; |
508034a3 | 689 | spinlock_t *ptl; |
ae859762 HD |
690 | int file_rss = 0; |
691 | int anon_rss = 0; | |
1da177e4 | 692 | |
508034a3 | 693 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
6606c3e0 | 694 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
695 | do { |
696 | pte_t ptent = *pte; | |
51c6f666 RH |
697 | if (pte_none(ptent)) { |
698 | (*zap_work)--; | |
1da177e4 | 699 | continue; |
51c6f666 | 700 | } |
6f5e6b9e HD |
701 | |
702 | (*zap_work) -= PAGE_SIZE; | |
703 | ||
1da177e4 | 704 | if (pte_present(ptent)) { |
ee498ed7 | 705 | struct page *page; |
51c6f666 | 706 | |
6aab341e | 707 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
708 | if (unlikely(details) && page) { |
709 | /* | |
710 | * unmap_shared_mapping_pages() wants to | |
711 | * invalidate cache without truncating: | |
712 | * unmap shared but keep private pages. | |
713 | */ | |
714 | if (details->check_mapping && | |
715 | details->check_mapping != page->mapping) | |
716 | continue; | |
717 | /* | |
718 | * Each page->index must be checked when | |
719 | * invalidating or truncating nonlinear. | |
720 | */ | |
721 | if (details->nonlinear_vma && | |
722 | (page->index < details->first_index || | |
723 | page->index > details->last_index)) | |
724 | continue; | |
725 | } | |
b5810039 | 726 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 727 | tlb->fullmm); |
1da177e4 LT |
728 | tlb_remove_tlb_entry(tlb, pte, addr); |
729 | if (unlikely(!page)) | |
730 | continue; | |
731 | if (unlikely(details) && details->nonlinear_vma | |
732 | && linear_page_index(details->nonlinear_vma, | |
733 | addr) != page->index) | |
b5810039 | 734 | set_pte_at(mm, addr, pte, |
1da177e4 | 735 | pgoff_to_pte(page->index)); |
1da177e4 | 736 | if (PageAnon(page)) |
86d912f4 | 737 | anon_rss--; |
6237bcd9 HD |
738 | else { |
739 | if (pte_dirty(ptent)) | |
740 | set_page_dirty(page); | |
741 | if (pte_young(ptent)) | |
daa88c8d | 742 | SetPageReferenced(page); |
86d912f4 | 743 | file_rss--; |
6237bcd9 | 744 | } |
7de6b805 | 745 | page_remove_rmap(page, vma); |
1da177e4 LT |
746 | tlb_remove_page(tlb, page); |
747 | continue; | |
748 | } | |
749 | /* | |
750 | * If details->check_mapping, we leave swap entries; | |
751 | * if details->nonlinear_vma, we leave file entries. | |
752 | */ | |
753 | if (unlikely(details)) | |
754 | continue; | |
755 | if (!pte_file(ptent)) | |
756 | free_swap_and_cache(pte_to_swp_entry(ptent)); | |
9888a1ca | 757 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); |
51c6f666 | 758 | } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); |
ae859762 | 759 | |
86d912f4 | 760 | add_mm_rss(mm, file_rss, anon_rss); |
6606c3e0 | 761 | arch_leave_lazy_mmu_mode(); |
508034a3 | 762 | pte_unmap_unlock(pte - 1, ptl); |
51c6f666 RH |
763 | |
764 | return addr; | |
1da177e4 LT |
765 | } |
766 | ||
51c6f666 | 767 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 768 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 769 | unsigned long addr, unsigned long end, |
51c6f666 | 770 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
771 | { |
772 | pmd_t *pmd; | |
773 | unsigned long next; | |
774 | ||
775 | pmd = pmd_offset(pud, addr); | |
776 | do { | |
777 | next = pmd_addr_end(addr, end); | |
51c6f666 RH |
778 | if (pmd_none_or_clear_bad(pmd)) { |
779 | (*zap_work)--; | |
1da177e4 | 780 | continue; |
51c6f666 RH |
781 | } |
782 | next = zap_pte_range(tlb, vma, pmd, addr, next, | |
783 | zap_work, details); | |
784 | } while (pmd++, addr = next, (addr != end && *zap_work > 0)); | |
785 | ||
786 | return addr; | |
1da177e4 LT |
787 | } |
788 | ||
51c6f666 | 789 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 790 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 791 | unsigned long addr, unsigned long end, |
51c6f666 | 792 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
793 | { |
794 | pud_t *pud; | |
795 | unsigned long next; | |
796 | ||
797 | pud = pud_offset(pgd, addr); | |
798 | do { | |
799 | next = pud_addr_end(addr, end); | |
51c6f666 RH |
800 | if (pud_none_or_clear_bad(pud)) { |
801 | (*zap_work)--; | |
1da177e4 | 802 | continue; |
51c6f666 RH |
803 | } |
804 | next = zap_pmd_range(tlb, vma, pud, addr, next, | |
805 | zap_work, details); | |
806 | } while (pud++, addr = next, (addr != end && *zap_work > 0)); | |
807 | ||
808 | return addr; | |
1da177e4 LT |
809 | } |
810 | ||
51c6f666 RH |
811 | static unsigned long unmap_page_range(struct mmu_gather *tlb, |
812 | struct vm_area_struct *vma, | |
1da177e4 | 813 | unsigned long addr, unsigned long end, |
51c6f666 | 814 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
815 | { |
816 | pgd_t *pgd; | |
817 | unsigned long next; | |
818 | ||
819 | if (details && !details->check_mapping && !details->nonlinear_vma) | |
820 | details = NULL; | |
821 | ||
822 | BUG_ON(addr >= end); | |
823 | tlb_start_vma(tlb, vma); | |
824 | pgd = pgd_offset(vma->vm_mm, addr); | |
825 | do { | |
826 | next = pgd_addr_end(addr, end); | |
51c6f666 RH |
827 | if (pgd_none_or_clear_bad(pgd)) { |
828 | (*zap_work)--; | |
1da177e4 | 829 | continue; |
51c6f666 RH |
830 | } |
831 | next = zap_pud_range(tlb, vma, pgd, addr, next, | |
832 | zap_work, details); | |
833 | } while (pgd++, addr = next, (addr != end && *zap_work > 0)); | |
1da177e4 | 834 | tlb_end_vma(tlb, vma); |
51c6f666 RH |
835 | |
836 | return addr; | |
1da177e4 LT |
837 | } |
838 | ||
839 | #ifdef CONFIG_PREEMPT | |
840 | # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) | |
841 | #else | |
842 | /* No preempt: go for improved straight-line efficiency */ | |
843 | # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) | |
844 | #endif | |
845 | ||
846 | /** | |
847 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
848 | * @tlbp: address of the caller's struct mmu_gather | |
1da177e4 LT |
849 | * @vma: the starting vma |
850 | * @start_addr: virtual address at which to start unmapping | |
851 | * @end_addr: virtual address at which to end unmapping | |
852 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here | |
853 | * @details: details of nonlinear truncation or shared cache invalidation | |
854 | * | |
ee39b37b | 855 | * Returns the end address of the unmapping (restart addr if interrupted). |
1da177e4 | 856 | * |
508034a3 | 857 | * Unmap all pages in the vma list. |
1da177e4 | 858 | * |
508034a3 HD |
859 | * We aim to not hold locks for too long (for scheduling latency reasons). |
860 | * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to | |
1da177e4 LT |
861 | * return the ending mmu_gather to the caller. |
862 | * | |
863 | * Only addresses between `start' and `end' will be unmapped. | |
864 | * | |
865 | * The VMA list must be sorted in ascending virtual address order. | |
866 | * | |
867 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
868 | * range after unmap_vmas() returns. So the only responsibility here is to | |
869 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
870 | * drops the lock and schedules. | |
871 | */ | |
508034a3 | 872 | unsigned long unmap_vmas(struct mmu_gather **tlbp, |
1da177e4 LT |
873 | struct vm_area_struct *vma, unsigned long start_addr, |
874 | unsigned long end_addr, unsigned long *nr_accounted, | |
875 | struct zap_details *details) | |
876 | { | |
51c6f666 | 877 | long zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
878 | unsigned long tlb_start = 0; /* For tlb_finish_mmu */ |
879 | int tlb_start_valid = 0; | |
ee39b37b | 880 | unsigned long start = start_addr; |
1da177e4 | 881 | spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; |
4d6ddfa9 | 882 | int fullmm = (*tlbp)->fullmm; |
1da177e4 LT |
883 | |
884 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { | |
1da177e4 LT |
885 | unsigned long end; |
886 | ||
887 | start = max(vma->vm_start, start_addr); | |
888 | if (start >= vma->vm_end) | |
889 | continue; | |
890 | end = min(vma->vm_end, end_addr); | |
891 | if (end <= vma->vm_start) | |
892 | continue; | |
893 | ||
894 | if (vma->vm_flags & VM_ACCOUNT) | |
895 | *nr_accounted += (end - start) >> PAGE_SHIFT; | |
896 | ||
1da177e4 | 897 | while (start != end) { |
1da177e4 LT |
898 | if (!tlb_start_valid) { |
899 | tlb_start = start; | |
900 | tlb_start_valid = 1; | |
901 | } | |
902 | ||
51c6f666 | 903 | if (unlikely(is_vm_hugetlb_page(vma))) { |
1da177e4 | 904 | unmap_hugepage_range(vma, start, end); |
51c6f666 RH |
905 | zap_work -= (end - start) / |
906 | (HPAGE_SIZE / PAGE_SIZE); | |
907 | start = end; | |
908 | } else | |
909 | start = unmap_page_range(*tlbp, vma, | |
910 | start, end, &zap_work, details); | |
911 | ||
912 | if (zap_work > 0) { | |
913 | BUG_ON(start != end); | |
914 | break; | |
1da177e4 LT |
915 | } |
916 | ||
1da177e4 LT |
917 | tlb_finish_mmu(*tlbp, tlb_start, start); |
918 | ||
919 | if (need_resched() || | |
95c354fe | 920 | (i_mmap_lock && spin_needbreak(i_mmap_lock))) { |
1da177e4 | 921 | if (i_mmap_lock) { |
508034a3 | 922 | *tlbp = NULL; |
1da177e4 LT |
923 | goto out; |
924 | } | |
1da177e4 | 925 | cond_resched(); |
1da177e4 LT |
926 | } |
927 | ||
508034a3 | 928 | *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); |
1da177e4 | 929 | tlb_start_valid = 0; |
51c6f666 | 930 | zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
931 | } |
932 | } | |
933 | out: | |
ee39b37b | 934 | return start; /* which is now the end (or restart) address */ |
1da177e4 LT |
935 | } |
936 | ||
937 | /** | |
938 | * zap_page_range - remove user pages in a given range | |
939 | * @vma: vm_area_struct holding the applicable pages | |
940 | * @address: starting address of pages to zap | |
941 | * @size: number of bytes to zap | |
942 | * @details: details of nonlinear truncation or shared cache invalidation | |
943 | */ | |
ee39b37b | 944 | unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
945 | unsigned long size, struct zap_details *details) |
946 | { | |
947 | struct mm_struct *mm = vma->vm_mm; | |
948 | struct mmu_gather *tlb; | |
949 | unsigned long end = address + size; | |
950 | unsigned long nr_accounted = 0; | |
951 | ||
1da177e4 | 952 | lru_add_drain(); |
1da177e4 | 953 | tlb = tlb_gather_mmu(mm, 0); |
365e9c87 | 954 | update_hiwater_rss(mm); |
508034a3 HD |
955 | end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); |
956 | if (tlb) | |
957 | tlb_finish_mmu(tlb, address, end); | |
ee39b37b | 958 | return end; |
1da177e4 LT |
959 | } |
960 | ||
961 | /* | |
962 | * Do a quick page-table lookup for a single page. | |
1da177e4 | 963 | */ |
6aab341e | 964 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 965 | unsigned int flags) |
1da177e4 LT |
966 | { |
967 | pgd_t *pgd; | |
968 | pud_t *pud; | |
969 | pmd_t *pmd; | |
970 | pte_t *ptep, pte; | |
deceb6cd | 971 | spinlock_t *ptl; |
1da177e4 | 972 | struct page *page; |
6aab341e | 973 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 974 | |
deceb6cd HD |
975 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
976 | if (!IS_ERR(page)) { | |
977 | BUG_ON(flags & FOLL_GET); | |
978 | goto out; | |
979 | } | |
1da177e4 | 980 | |
deceb6cd | 981 | page = NULL; |
1da177e4 LT |
982 | pgd = pgd_offset(mm, address); |
983 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
deceb6cd | 984 | goto no_page_table; |
1da177e4 LT |
985 | |
986 | pud = pud_offset(pgd, address); | |
987 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
deceb6cd | 988 | goto no_page_table; |
1da177e4 LT |
989 | |
990 | pmd = pmd_offset(pud, address); | |
aeed5fce | 991 | if (pmd_none(*pmd)) |
deceb6cd HD |
992 | goto no_page_table; |
993 | ||
994 | if (pmd_huge(*pmd)) { | |
995 | BUG_ON(flags & FOLL_GET); | |
996 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); | |
1da177e4 | 997 | goto out; |
deceb6cd | 998 | } |
1da177e4 | 999 | |
aeed5fce HD |
1000 | if (unlikely(pmd_bad(*pmd))) |
1001 | goto no_page_table; | |
1002 | ||
deceb6cd | 1003 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
1004 | |
1005 | pte = *ptep; | |
deceb6cd | 1006 | if (!pte_present(pte)) |
89f5b7da | 1007 | goto no_page; |
deceb6cd HD |
1008 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
1009 | goto unlock; | |
6aab341e LT |
1010 | page = vm_normal_page(vma, address, pte); |
1011 | if (unlikely(!page)) | |
89f5b7da | 1012 | goto bad_page; |
1da177e4 | 1013 | |
deceb6cd HD |
1014 | if (flags & FOLL_GET) |
1015 | get_page(page); | |
1016 | if (flags & FOLL_TOUCH) { | |
1017 | if ((flags & FOLL_WRITE) && | |
1018 | !pte_dirty(pte) && !PageDirty(page)) | |
1019 | set_page_dirty(page); | |
1020 | mark_page_accessed(page); | |
1021 | } | |
1022 | unlock: | |
1023 | pte_unmap_unlock(ptep, ptl); | |
1da177e4 | 1024 | out: |
deceb6cd | 1025 | return page; |
1da177e4 | 1026 | |
89f5b7da LT |
1027 | bad_page: |
1028 | pte_unmap_unlock(ptep, ptl); | |
1029 | return ERR_PTR(-EFAULT); | |
1030 | ||
1031 | no_page: | |
1032 | pte_unmap_unlock(ptep, ptl); | |
1033 | if (!pte_none(pte)) | |
1034 | return page; | |
1035 | /* Fall through to ZERO_PAGE handling */ | |
deceb6cd HD |
1036 | no_page_table: |
1037 | /* | |
1038 | * When core dumping an enormous anonymous area that nobody | |
1039 | * has touched so far, we don't want to allocate page tables. | |
1040 | */ | |
1041 | if (flags & FOLL_ANON) { | |
557ed1fa | 1042 | page = ZERO_PAGE(0); |
deceb6cd HD |
1043 | if (flags & FOLL_GET) |
1044 | get_page(page); | |
1045 | BUG_ON(flags & FOLL_WRITE); | |
1046 | } | |
1047 | return page; | |
1da177e4 LT |
1048 | } |
1049 | ||
672ca28e LT |
1050 | /* Can we do the FOLL_ANON optimization? */ |
1051 | static inline int use_zero_page(struct vm_area_struct *vma) | |
1052 | { | |
1053 | /* | |
1054 | * We don't want to optimize FOLL_ANON for make_pages_present() | |
1055 | * when it tries to page in a VM_LOCKED region. As to VM_SHARED, | |
1056 | * we want to get the page from the page tables to make sure | |
1057 | * that we serialize and update with any other user of that | |
1058 | * mapping. | |
1059 | */ | |
1060 | if (vma->vm_flags & (VM_LOCKED | VM_SHARED)) | |
1061 | return 0; | |
1062 | /* | |
0d71d10a | 1063 | * And if we have a fault routine, it's not an anonymous region. |
672ca28e | 1064 | */ |
0d71d10a | 1065 | return !vma->vm_ops || !vma->vm_ops->fault; |
672ca28e LT |
1066 | } |
1067 | ||
1da177e4 LT |
1068 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, |
1069 | unsigned long start, int len, int write, int force, | |
1070 | struct page **pages, struct vm_area_struct **vmas) | |
1071 | { | |
1072 | int i; | |
deceb6cd | 1073 | unsigned int vm_flags; |
1da177e4 | 1074 | |
900cf086 JC |
1075 | if (len <= 0) |
1076 | return 0; | |
1da177e4 LT |
1077 | /* |
1078 | * Require read or write permissions. | |
1079 | * If 'force' is set, we only require the "MAY" flags. | |
1080 | */ | |
deceb6cd HD |
1081 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
1082 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 LT |
1083 | i = 0; |
1084 | ||
1085 | do { | |
deceb6cd HD |
1086 | struct vm_area_struct *vma; |
1087 | unsigned int foll_flags; | |
1da177e4 LT |
1088 | |
1089 | vma = find_extend_vma(mm, start); | |
1090 | if (!vma && in_gate_area(tsk, start)) { | |
1091 | unsigned long pg = start & PAGE_MASK; | |
1092 | struct vm_area_struct *gate_vma = get_gate_vma(tsk); | |
1093 | pgd_t *pgd; | |
1094 | pud_t *pud; | |
1095 | pmd_t *pmd; | |
1096 | pte_t *pte; | |
1097 | if (write) /* user gate pages are read-only */ | |
1098 | return i ? : -EFAULT; | |
1099 | if (pg > TASK_SIZE) | |
1100 | pgd = pgd_offset_k(pg); | |
1101 | else | |
1102 | pgd = pgd_offset_gate(mm, pg); | |
1103 | BUG_ON(pgd_none(*pgd)); | |
1104 | pud = pud_offset(pgd, pg); | |
1105 | BUG_ON(pud_none(*pud)); | |
1106 | pmd = pmd_offset(pud, pg); | |
690dbe1c HD |
1107 | if (pmd_none(*pmd)) |
1108 | return i ? : -EFAULT; | |
1da177e4 | 1109 | pte = pte_offset_map(pmd, pg); |
690dbe1c HD |
1110 | if (pte_none(*pte)) { |
1111 | pte_unmap(pte); | |
1112 | return i ? : -EFAULT; | |
1113 | } | |
1da177e4 | 1114 | if (pages) { |
fa2a455b | 1115 | struct page *page = vm_normal_page(gate_vma, start, *pte); |
6aab341e LT |
1116 | pages[i] = page; |
1117 | if (page) | |
1118 | get_page(page); | |
1da177e4 LT |
1119 | } |
1120 | pte_unmap(pte); | |
1121 | if (vmas) | |
1122 | vmas[i] = gate_vma; | |
1123 | i++; | |
1124 | start += PAGE_SIZE; | |
1125 | len--; | |
1126 | continue; | |
1127 | } | |
1128 | ||
1ff80389 | 1129 | if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) |
deceb6cd | 1130 | || !(vm_flags & vma->vm_flags)) |
1da177e4 LT |
1131 | return i ? : -EFAULT; |
1132 | ||
1133 | if (is_vm_hugetlb_page(vma)) { | |
1134 | i = follow_hugetlb_page(mm, vma, pages, vmas, | |
5b23dbe8 | 1135 | &start, &len, i, write); |
1da177e4 LT |
1136 | continue; |
1137 | } | |
deceb6cd HD |
1138 | |
1139 | foll_flags = FOLL_TOUCH; | |
1140 | if (pages) | |
1141 | foll_flags |= FOLL_GET; | |
672ca28e | 1142 | if (!write && use_zero_page(vma)) |
deceb6cd HD |
1143 | foll_flags |= FOLL_ANON; |
1144 | ||
1da177e4 | 1145 | do { |
08ef4729 | 1146 | struct page *page; |
1da177e4 | 1147 | |
462e00cc ES |
1148 | /* |
1149 | * If tsk is ooming, cut off its access to large memory | |
1150 | * allocations. It has a pending SIGKILL, but it can't | |
1151 | * be processed until returning to user space. | |
1152 | */ | |
1153 | if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE))) | |
7a36a752 | 1154 | return i ? i : -ENOMEM; |
462e00cc | 1155 | |
deceb6cd HD |
1156 | if (write) |
1157 | foll_flags |= FOLL_WRITE; | |
a68d2ebc | 1158 | |
deceb6cd | 1159 | cond_resched(); |
6aab341e | 1160 | while (!(page = follow_page(vma, start, foll_flags))) { |
deceb6cd | 1161 | int ret; |
83c54070 | 1162 | ret = handle_mm_fault(mm, vma, start, |
deceb6cd | 1163 | foll_flags & FOLL_WRITE); |
83c54070 NP |
1164 | if (ret & VM_FAULT_ERROR) { |
1165 | if (ret & VM_FAULT_OOM) | |
1166 | return i ? i : -ENOMEM; | |
1167 | else if (ret & VM_FAULT_SIGBUS) | |
1168 | return i ? i : -EFAULT; | |
1169 | BUG(); | |
1170 | } | |
1171 | if (ret & VM_FAULT_MAJOR) | |
1172 | tsk->maj_flt++; | |
1173 | else | |
1174 | tsk->min_flt++; | |
1175 | ||
a68d2ebc | 1176 | /* |
83c54070 NP |
1177 | * The VM_FAULT_WRITE bit tells us that |
1178 | * do_wp_page has broken COW when necessary, | |
1179 | * even if maybe_mkwrite decided not to set | |
1180 | * pte_write. We can thus safely do subsequent | |
1181 | * page lookups as if they were reads. | |
a68d2ebc LT |
1182 | */ |
1183 | if (ret & VM_FAULT_WRITE) | |
deceb6cd | 1184 | foll_flags &= ~FOLL_WRITE; |
83c54070 | 1185 | |
7f7bbbe5 | 1186 | cond_resched(); |
1da177e4 | 1187 | } |
89f5b7da LT |
1188 | if (IS_ERR(page)) |
1189 | return i ? i : PTR_ERR(page); | |
1da177e4 | 1190 | if (pages) { |
08ef4729 | 1191 | pages[i] = page; |
03beb076 | 1192 | |
a6f36be3 | 1193 | flush_anon_page(vma, page, start); |
08ef4729 | 1194 | flush_dcache_page(page); |
1da177e4 LT |
1195 | } |
1196 | if (vmas) | |
1197 | vmas[i] = vma; | |
1198 | i++; | |
1199 | start += PAGE_SIZE; | |
1200 | len--; | |
08ef4729 | 1201 | } while (len && start < vma->vm_end); |
08ef4729 | 1202 | } while (len); |
1da177e4 LT |
1203 | return i; |
1204 | } | |
1da177e4 LT |
1205 | EXPORT_SYMBOL(get_user_pages); |
1206 | ||
920c7a5d HH |
1207 | pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, |
1208 | spinlock_t **ptl) | |
c9cfcddf LT |
1209 | { |
1210 | pgd_t * pgd = pgd_offset(mm, addr); | |
1211 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
1212 | if (pud) { | |
49c91fb0 | 1213 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
c9cfcddf LT |
1214 | if (pmd) |
1215 | return pte_alloc_map_lock(mm, pmd, addr, ptl); | |
1216 | } | |
1217 | return NULL; | |
1218 | } | |
1219 | ||
238f58d8 LT |
1220 | /* |
1221 | * This is the old fallback for page remapping. | |
1222 | * | |
1223 | * For historical reasons, it only allows reserved pages. Only | |
1224 | * old drivers should use this, and they needed to mark their | |
1225 | * pages reserved for the old functions anyway. | |
1226 | */ | |
423bad60 NP |
1227 | static int insert_page(struct vm_area_struct *vma, unsigned long addr, |
1228 | struct page *page, pgprot_t prot) | |
238f58d8 | 1229 | { |
423bad60 | 1230 | struct mm_struct *mm = vma->vm_mm; |
238f58d8 | 1231 | int retval; |
c9cfcddf | 1232 | pte_t *pte; |
8a9f3ccd BS |
1233 | spinlock_t *ptl; |
1234 | ||
e1a1cd59 | 1235 | retval = mem_cgroup_charge(page, mm, GFP_KERNEL); |
8a9f3ccd BS |
1236 | if (retval) |
1237 | goto out; | |
238f58d8 LT |
1238 | |
1239 | retval = -EINVAL; | |
a145dd41 | 1240 | if (PageAnon(page)) |
8a9f3ccd | 1241 | goto out_uncharge; |
238f58d8 LT |
1242 | retval = -ENOMEM; |
1243 | flush_dcache_page(page); | |
c9cfcddf | 1244 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 | 1245 | if (!pte) |
8a9f3ccd | 1246 | goto out_uncharge; |
238f58d8 LT |
1247 | retval = -EBUSY; |
1248 | if (!pte_none(*pte)) | |
1249 | goto out_unlock; | |
1250 | ||
1251 | /* Ok, finally just insert the thing.. */ | |
1252 | get_page(page); | |
1253 | inc_mm_counter(mm, file_rss); | |
1254 | page_add_file_rmap(page); | |
1255 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); | |
1256 | ||
1257 | retval = 0; | |
8a9f3ccd BS |
1258 | pte_unmap_unlock(pte, ptl); |
1259 | return retval; | |
238f58d8 LT |
1260 | out_unlock: |
1261 | pte_unmap_unlock(pte, ptl); | |
8a9f3ccd BS |
1262 | out_uncharge: |
1263 | mem_cgroup_uncharge_page(page); | |
238f58d8 LT |
1264 | out: |
1265 | return retval; | |
1266 | } | |
1267 | ||
bfa5bf6d REB |
1268 | /** |
1269 | * vm_insert_page - insert single page into user vma | |
1270 | * @vma: user vma to map to | |
1271 | * @addr: target user address of this page | |
1272 | * @page: source kernel page | |
1273 | * | |
a145dd41 LT |
1274 | * This allows drivers to insert individual pages they've allocated |
1275 | * into a user vma. | |
1276 | * | |
1277 | * The page has to be a nice clean _individual_ kernel allocation. | |
1278 | * If you allocate a compound page, you need to have marked it as | |
1279 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 1280 | * (see split_page()). |
a145dd41 LT |
1281 | * |
1282 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
1283 | * took an arbitrary page protection parameter. This doesn't allow | |
1284 | * that. Your vma protection will have to be set up correctly, which | |
1285 | * means that if you want a shared writable mapping, you'd better | |
1286 | * ask for a shared writable mapping! | |
1287 | * | |
1288 | * The page does not need to be reserved. | |
1289 | */ | |
423bad60 NP |
1290 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
1291 | struct page *page) | |
a145dd41 LT |
1292 | { |
1293 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1294 | return -EFAULT; | |
1295 | if (!page_count(page)) | |
1296 | return -EINVAL; | |
4d7672b4 | 1297 | vma->vm_flags |= VM_INSERTPAGE; |
423bad60 | 1298 | return insert_page(vma, addr, page, vma->vm_page_prot); |
a145dd41 | 1299 | } |
e3c3374f | 1300 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 1301 | |
423bad60 NP |
1302 | static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, |
1303 | unsigned long pfn, pgprot_t prot) | |
1304 | { | |
1305 | struct mm_struct *mm = vma->vm_mm; | |
1306 | int retval; | |
1307 | pte_t *pte, entry; | |
1308 | spinlock_t *ptl; | |
1309 | ||
1310 | retval = -ENOMEM; | |
1311 | pte = get_locked_pte(mm, addr, &ptl); | |
1312 | if (!pte) | |
1313 | goto out; | |
1314 | retval = -EBUSY; | |
1315 | if (!pte_none(*pte)) | |
1316 | goto out_unlock; | |
1317 | ||
1318 | /* Ok, finally just insert the thing.. */ | |
1319 | entry = pte_mkspecial(pfn_pte(pfn, prot)); | |
1320 | set_pte_at(mm, addr, pte, entry); | |
1321 | update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */ | |
1322 | ||
1323 | retval = 0; | |
1324 | out_unlock: | |
1325 | pte_unmap_unlock(pte, ptl); | |
1326 | out: | |
1327 | return retval; | |
1328 | } | |
1329 | ||
e0dc0d8f NP |
1330 | /** |
1331 | * vm_insert_pfn - insert single pfn into user vma | |
1332 | * @vma: user vma to map to | |
1333 | * @addr: target user address of this page | |
1334 | * @pfn: source kernel pfn | |
1335 | * | |
1336 | * Similar to vm_inert_page, this allows drivers to insert individual pages | |
1337 | * they've allocated into a user vma. Same comments apply. | |
1338 | * | |
1339 | * This function should only be called from a vm_ops->fault handler, and | |
1340 | * in that case the handler should return NULL. | |
0d71d10a NP |
1341 | * |
1342 | * vma cannot be a COW mapping. | |
1343 | * | |
1344 | * As this is called only for pages that do not currently exist, we | |
1345 | * do not need to flush old virtual caches or the TLB. | |
e0dc0d8f NP |
1346 | */ |
1347 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
423bad60 | 1348 | unsigned long pfn) |
e0dc0d8f | 1349 | { |
7e675137 NP |
1350 | /* |
1351 | * Technically, architectures with pte_special can avoid all these | |
1352 | * restrictions (same for remap_pfn_range). However we would like | |
1353 | * consistency in testing and feature parity among all, so we should | |
1354 | * try to keep these invariants in place for everybody. | |
1355 | */ | |
b379d790 JH |
1356 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); |
1357 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
1358 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1359 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
1360 | BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); | |
e0dc0d8f | 1361 | |
423bad60 NP |
1362 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1363 | return -EFAULT; | |
1364 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
1365 | } | |
1366 | EXPORT_SYMBOL(vm_insert_pfn); | |
e0dc0d8f | 1367 | |
423bad60 NP |
1368 | int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, |
1369 | unsigned long pfn) | |
1370 | { | |
1371 | BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); | |
e0dc0d8f | 1372 | |
423bad60 NP |
1373 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1374 | return -EFAULT; | |
e0dc0d8f | 1375 | |
423bad60 NP |
1376 | /* |
1377 | * If we don't have pte special, then we have to use the pfn_valid() | |
1378 | * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* | |
1379 | * refcount the page if pfn_valid is true (hence insert_page rather | |
1380 | * than insert_pfn). | |
1381 | */ | |
1382 | if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) { | |
1383 | struct page *page; | |
1384 | ||
1385 | page = pfn_to_page(pfn); | |
1386 | return insert_page(vma, addr, page, vma->vm_page_prot); | |
1387 | } | |
1388 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
e0dc0d8f | 1389 | } |
423bad60 | 1390 | EXPORT_SYMBOL(vm_insert_mixed); |
e0dc0d8f | 1391 | |
1da177e4 LT |
1392 | /* |
1393 | * maps a range of physical memory into the requested pages. the old | |
1394 | * mappings are removed. any references to nonexistent pages results | |
1395 | * in null mappings (currently treated as "copy-on-access") | |
1396 | */ | |
1397 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
1398 | unsigned long addr, unsigned long end, | |
1399 | unsigned long pfn, pgprot_t prot) | |
1400 | { | |
1401 | pte_t *pte; | |
c74df32c | 1402 | spinlock_t *ptl; |
1da177e4 | 1403 | |
c74df32c | 1404 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
1405 | if (!pte) |
1406 | return -ENOMEM; | |
6606c3e0 | 1407 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1408 | do { |
1409 | BUG_ON(!pte_none(*pte)); | |
7e675137 | 1410 | set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); |
1da177e4 LT |
1411 | pfn++; |
1412 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 1413 | arch_leave_lazy_mmu_mode(); |
c74df32c | 1414 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
1415 | return 0; |
1416 | } | |
1417 | ||
1418 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1419 | unsigned long addr, unsigned long end, | |
1420 | unsigned long pfn, pgprot_t prot) | |
1421 | { | |
1422 | pmd_t *pmd; | |
1423 | unsigned long next; | |
1424 | ||
1425 | pfn -= addr >> PAGE_SHIFT; | |
1426 | pmd = pmd_alloc(mm, pud, addr); | |
1427 | if (!pmd) | |
1428 | return -ENOMEM; | |
1429 | do { | |
1430 | next = pmd_addr_end(addr, end); | |
1431 | if (remap_pte_range(mm, pmd, addr, next, | |
1432 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1433 | return -ENOMEM; | |
1434 | } while (pmd++, addr = next, addr != end); | |
1435 | return 0; | |
1436 | } | |
1437 | ||
1438 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1439 | unsigned long addr, unsigned long end, | |
1440 | unsigned long pfn, pgprot_t prot) | |
1441 | { | |
1442 | pud_t *pud; | |
1443 | unsigned long next; | |
1444 | ||
1445 | pfn -= addr >> PAGE_SHIFT; | |
1446 | pud = pud_alloc(mm, pgd, addr); | |
1447 | if (!pud) | |
1448 | return -ENOMEM; | |
1449 | do { | |
1450 | next = pud_addr_end(addr, end); | |
1451 | if (remap_pmd_range(mm, pud, addr, next, | |
1452 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1453 | return -ENOMEM; | |
1454 | } while (pud++, addr = next, addr != end); | |
1455 | return 0; | |
1456 | } | |
1457 | ||
bfa5bf6d REB |
1458 | /** |
1459 | * remap_pfn_range - remap kernel memory to userspace | |
1460 | * @vma: user vma to map to | |
1461 | * @addr: target user address to start at | |
1462 | * @pfn: physical address of kernel memory | |
1463 | * @size: size of map area | |
1464 | * @prot: page protection flags for this mapping | |
1465 | * | |
1466 | * Note: this is only safe if the mm semaphore is held when called. | |
1467 | */ | |
1da177e4 LT |
1468 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
1469 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
1470 | { | |
1471 | pgd_t *pgd; | |
1472 | unsigned long next; | |
2d15cab8 | 1473 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 LT |
1474 | struct mm_struct *mm = vma->vm_mm; |
1475 | int err; | |
1476 | ||
1477 | /* | |
1478 | * Physically remapped pages are special. Tell the | |
1479 | * rest of the world about it: | |
1480 | * VM_IO tells people not to look at these pages | |
1481 | * (accesses can have side effects). | |
0b14c179 HD |
1482 | * VM_RESERVED is specified all over the place, because |
1483 | * in 2.4 it kept swapout's vma scan off this vma; but | |
1484 | * in 2.6 the LRU scan won't even find its pages, so this | |
1485 | * flag means no more than count its pages in reserved_vm, | |
1486 | * and omit it from core dump, even when VM_IO turned off. | |
6aab341e LT |
1487 | * VM_PFNMAP tells the core MM that the base pages are just |
1488 | * raw PFN mappings, and do not have a "struct page" associated | |
1489 | * with them. | |
fb155c16 LT |
1490 | * |
1491 | * There's a horrible special case to handle copy-on-write | |
1492 | * behaviour that some programs depend on. We mark the "original" | |
1493 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
1da177e4 | 1494 | */ |
67121172 | 1495 | if (is_cow_mapping(vma->vm_flags)) { |
fb155c16 | 1496 | if (addr != vma->vm_start || end != vma->vm_end) |
7fc7e2ee | 1497 | return -EINVAL; |
fb155c16 LT |
1498 | vma->vm_pgoff = pfn; |
1499 | } | |
1500 | ||
6aab341e | 1501 | vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; |
1da177e4 LT |
1502 | |
1503 | BUG_ON(addr >= end); | |
1504 | pfn -= addr >> PAGE_SHIFT; | |
1505 | pgd = pgd_offset(mm, addr); | |
1506 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
1507 | do { |
1508 | next = pgd_addr_end(addr, end); | |
1509 | err = remap_pud_range(mm, pgd, addr, next, | |
1510 | pfn + (addr >> PAGE_SHIFT), prot); | |
1511 | if (err) | |
1512 | break; | |
1513 | } while (pgd++, addr = next, addr != end); | |
1da177e4 LT |
1514 | return err; |
1515 | } | |
1516 | EXPORT_SYMBOL(remap_pfn_range); | |
1517 | ||
aee16b3c JF |
1518 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
1519 | unsigned long addr, unsigned long end, | |
1520 | pte_fn_t fn, void *data) | |
1521 | { | |
1522 | pte_t *pte; | |
1523 | int err; | |
2f569afd | 1524 | pgtable_t token; |
94909914 | 1525 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
1526 | |
1527 | pte = (mm == &init_mm) ? | |
1528 | pte_alloc_kernel(pmd, addr) : | |
1529 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
1530 | if (!pte) | |
1531 | return -ENOMEM; | |
1532 | ||
1533 | BUG_ON(pmd_huge(*pmd)); | |
1534 | ||
2f569afd | 1535 | token = pmd_pgtable(*pmd); |
aee16b3c JF |
1536 | |
1537 | do { | |
2f569afd | 1538 | err = fn(pte, token, addr, data); |
aee16b3c JF |
1539 | if (err) |
1540 | break; | |
1541 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
1542 | ||
1543 | if (mm != &init_mm) | |
1544 | pte_unmap_unlock(pte-1, ptl); | |
1545 | return err; | |
1546 | } | |
1547 | ||
1548 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1549 | unsigned long addr, unsigned long end, | |
1550 | pte_fn_t fn, void *data) | |
1551 | { | |
1552 | pmd_t *pmd; | |
1553 | unsigned long next; | |
1554 | int err; | |
1555 | ||
1556 | pmd = pmd_alloc(mm, pud, addr); | |
1557 | if (!pmd) | |
1558 | return -ENOMEM; | |
1559 | do { | |
1560 | next = pmd_addr_end(addr, end); | |
1561 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
1562 | if (err) | |
1563 | break; | |
1564 | } while (pmd++, addr = next, addr != end); | |
1565 | return err; | |
1566 | } | |
1567 | ||
1568 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1569 | unsigned long addr, unsigned long end, | |
1570 | pte_fn_t fn, void *data) | |
1571 | { | |
1572 | pud_t *pud; | |
1573 | unsigned long next; | |
1574 | int err; | |
1575 | ||
1576 | pud = pud_alloc(mm, pgd, addr); | |
1577 | if (!pud) | |
1578 | return -ENOMEM; | |
1579 | do { | |
1580 | next = pud_addr_end(addr, end); | |
1581 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
1582 | if (err) | |
1583 | break; | |
1584 | } while (pud++, addr = next, addr != end); | |
1585 | return err; | |
1586 | } | |
1587 | ||
1588 | /* | |
1589 | * Scan a region of virtual memory, filling in page tables as necessary | |
1590 | * and calling a provided function on each leaf page table. | |
1591 | */ | |
1592 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
1593 | unsigned long size, pte_fn_t fn, void *data) | |
1594 | { | |
1595 | pgd_t *pgd; | |
1596 | unsigned long next; | |
1597 | unsigned long end = addr + size; | |
1598 | int err; | |
1599 | ||
1600 | BUG_ON(addr >= end); | |
1601 | pgd = pgd_offset(mm, addr); | |
1602 | do { | |
1603 | next = pgd_addr_end(addr, end); | |
1604 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
1605 | if (err) | |
1606 | break; | |
1607 | } while (pgd++, addr = next, addr != end); | |
1608 | return err; | |
1609 | } | |
1610 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
1611 | ||
8f4e2101 HD |
1612 | /* |
1613 | * handle_pte_fault chooses page fault handler according to an entry | |
1614 | * which was read non-atomically. Before making any commitment, on | |
1615 | * those architectures or configurations (e.g. i386 with PAE) which | |
1616 | * might give a mix of unmatched parts, do_swap_page and do_file_page | |
1617 | * must check under lock before unmapping the pte and proceeding | |
1618 | * (but do_wp_page is only called after already making such a check; | |
1619 | * and do_anonymous_page and do_no_page can safely check later on). | |
1620 | */ | |
4c21e2f2 | 1621 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
1622 | pte_t *page_table, pte_t orig_pte) |
1623 | { | |
1624 | int same = 1; | |
1625 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
1626 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
1627 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
1628 | spin_lock(ptl); | |
8f4e2101 | 1629 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 1630 | spin_unlock(ptl); |
8f4e2101 HD |
1631 | } |
1632 | #endif | |
1633 | pte_unmap(page_table); | |
1634 | return same; | |
1635 | } | |
1636 | ||
1da177e4 LT |
1637 | /* |
1638 | * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when | |
1639 | * servicing faults for write access. In the normal case, do always want | |
1640 | * pte_mkwrite. But get_user_pages can cause write faults for mappings | |
1641 | * that do not have writing enabled, when used by access_process_vm. | |
1642 | */ | |
1643 | static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) | |
1644 | { | |
1645 | if (likely(vma->vm_flags & VM_WRITE)) | |
1646 | pte = pte_mkwrite(pte); | |
1647 | return pte; | |
1648 | } | |
1649 | ||
9de455b2 | 1650 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e LT |
1651 | { |
1652 | /* | |
1653 | * If the source page was a PFN mapping, we don't have | |
1654 | * a "struct page" for it. We do a best-effort copy by | |
1655 | * just copying from the original user address. If that | |
1656 | * fails, we just zero-fill it. Live with it. | |
1657 | */ | |
1658 | if (unlikely(!src)) { | |
1659 | void *kaddr = kmap_atomic(dst, KM_USER0); | |
5d2a2dbb LT |
1660 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
1661 | ||
1662 | /* | |
1663 | * This really shouldn't fail, because the page is there | |
1664 | * in the page tables. But it might just be unreadable, | |
1665 | * in which case we just give up and fill the result with | |
1666 | * zeroes. | |
1667 | */ | |
1668 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
6aab341e LT |
1669 | memset(kaddr, 0, PAGE_SIZE); |
1670 | kunmap_atomic(kaddr, KM_USER0); | |
c4ec7b0d | 1671 | flush_dcache_page(dst); |
0ed361de NP |
1672 | } else |
1673 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
1674 | } |
1675 | ||
1da177e4 LT |
1676 | /* |
1677 | * This routine handles present pages, when users try to write | |
1678 | * to a shared page. It is done by copying the page to a new address | |
1679 | * and decrementing the shared-page counter for the old page. | |
1680 | * | |
1da177e4 LT |
1681 | * Note that this routine assumes that the protection checks have been |
1682 | * done by the caller (the low-level page fault routine in most cases). | |
1683 | * Thus we can safely just mark it writable once we've done any necessary | |
1684 | * COW. | |
1685 | * | |
1686 | * We also mark the page dirty at this point even though the page will | |
1687 | * change only once the write actually happens. This avoids a few races, | |
1688 | * and potentially makes it more efficient. | |
1689 | * | |
8f4e2101 HD |
1690 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
1691 | * but allow concurrent faults), with pte both mapped and locked. | |
1692 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 1693 | */ |
65500d23 HD |
1694 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1695 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
8f4e2101 | 1696 | spinlock_t *ptl, pte_t orig_pte) |
1da177e4 | 1697 | { |
e5bbe4df | 1698 | struct page *old_page, *new_page; |
1da177e4 | 1699 | pte_t entry; |
83c54070 | 1700 | int reuse = 0, ret = 0; |
a200ee18 | 1701 | int page_mkwrite = 0; |
d08b3851 | 1702 | struct page *dirty_page = NULL; |
1da177e4 | 1703 | |
6aab341e | 1704 | old_page = vm_normal_page(vma, address, orig_pte); |
251b97f5 PZ |
1705 | if (!old_page) { |
1706 | /* | |
1707 | * VM_MIXEDMAP !pfn_valid() case | |
1708 | * | |
1709 | * We should not cow pages in a shared writeable mapping. | |
1710 | * Just mark the pages writable as we can't do any dirty | |
1711 | * accounting on raw pfn maps. | |
1712 | */ | |
1713 | if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
1714 | (VM_WRITE|VM_SHARED)) | |
1715 | goto reuse; | |
6aab341e | 1716 | goto gotten; |
251b97f5 | 1717 | } |
1da177e4 | 1718 | |
d08b3851 | 1719 | /* |
ee6a6457 PZ |
1720 | * Take out anonymous pages first, anonymous shared vmas are |
1721 | * not dirty accountable. | |
d08b3851 | 1722 | */ |
ee6a6457 PZ |
1723 | if (PageAnon(old_page)) { |
1724 | if (!TestSetPageLocked(old_page)) { | |
1725 | reuse = can_share_swap_page(old_page); | |
1726 | unlock_page(old_page); | |
1727 | } | |
1728 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
d08b3851 | 1729 | (VM_WRITE|VM_SHARED))) { |
ee6a6457 PZ |
1730 | /* |
1731 | * Only catch write-faults on shared writable pages, | |
1732 | * read-only shared pages can get COWed by | |
1733 | * get_user_pages(.write=1, .force=1). | |
1734 | */ | |
9637a5ef DH |
1735 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
1736 | /* | |
1737 | * Notify the address space that the page is about to | |
1738 | * become writable so that it can prohibit this or wait | |
1739 | * for the page to get into an appropriate state. | |
1740 | * | |
1741 | * We do this without the lock held, so that it can | |
1742 | * sleep if it needs to. | |
1743 | */ | |
1744 | page_cache_get(old_page); | |
1745 | pte_unmap_unlock(page_table, ptl); | |
1746 | ||
1747 | if (vma->vm_ops->page_mkwrite(vma, old_page) < 0) | |
1748 | goto unwritable_page; | |
1749 | ||
9637a5ef DH |
1750 | /* |
1751 | * Since we dropped the lock we need to revalidate | |
1752 | * the PTE as someone else may have changed it. If | |
1753 | * they did, we just return, as we can count on the | |
1754 | * MMU to tell us if they didn't also make it writable. | |
1755 | */ | |
1756 | page_table = pte_offset_map_lock(mm, pmd, address, | |
1757 | &ptl); | |
c3704ceb | 1758 | page_cache_release(old_page); |
9637a5ef DH |
1759 | if (!pte_same(*page_table, orig_pte)) |
1760 | goto unlock; | |
a200ee18 PZ |
1761 | |
1762 | page_mkwrite = 1; | |
1da177e4 | 1763 | } |
d08b3851 PZ |
1764 | dirty_page = old_page; |
1765 | get_page(dirty_page); | |
9637a5ef | 1766 | reuse = 1; |
9637a5ef DH |
1767 | } |
1768 | ||
1769 | if (reuse) { | |
251b97f5 | 1770 | reuse: |
9637a5ef DH |
1771 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
1772 | entry = pte_mkyoung(orig_pte); | |
1773 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
954ffcb3 | 1774 | if (ptep_set_access_flags(vma, address, page_table, entry,1)) |
8dab5241 | 1775 | update_mmu_cache(vma, address, entry); |
9637a5ef DH |
1776 | ret |= VM_FAULT_WRITE; |
1777 | goto unlock; | |
1da177e4 | 1778 | } |
1da177e4 LT |
1779 | |
1780 | /* | |
1781 | * Ok, we need to copy. Oh, well.. | |
1782 | */ | |
b5810039 | 1783 | page_cache_get(old_page); |
920fc356 | 1784 | gotten: |
8f4e2101 | 1785 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
1786 | |
1787 | if (unlikely(anon_vma_prepare(vma))) | |
65500d23 | 1788 | goto oom; |
557ed1fa NP |
1789 | VM_BUG_ON(old_page == ZERO_PAGE(0)); |
1790 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
1791 | if (!new_page) | |
1792 | goto oom; | |
1793 | cow_user_page(new_page, old_page, address, vma); | |
0ed361de | 1794 | __SetPageUptodate(new_page); |
65500d23 | 1795 | |
e1a1cd59 | 1796 | if (mem_cgroup_charge(new_page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
1797 | goto oom_free_new; |
1798 | ||
1da177e4 LT |
1799 | /* |
1800 | * Re-check the pte - we dropped the lock | |
1801 | */ | |
8f4e2101 | 1802 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
65500d23 | 1803 | if (likely(pte_same(*page_table, orig_pte))) { |
920fc356 | 1804 | if (old_page) { |
920fc356 HD |
1805 | if (!PageAnon(old_page)) { |
1806 | dec_mm_counter(mm, file_rss); | |
1807 | inc_mm_counter(mm, anon_rss); | |
1808 | } | |
1809 | } else | |
4294621f | 1810 | inc_mm_counter(mm, anon_rss); |
eca35133 | 1811 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
65500d23 HD |
1812 | entry = mk_pte(new_page, vma->vm_page_prot); |
1813 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
4ce072f1 SS |
1814 | /* |
1815 | * Clear the pte entry and flush it first, before updating the | |
1816 | * pte with the new entry. This will avoid a race condition | |
1817 | * seen in the presence of one thread doing SMC and another | |
1818 | * thread doing COW. | |
1819 | */ | |
1820 | ptep_clear_flush(vma, address, page_table); | |
1821 | set_pte_at(mm, address, page_table, entry); | |
65500d23 | 1822 | update_mmu_cache(vma, address, entry); |
1da177e4 | 1823 | lru_cache_add_active(new_page); |
9617d95e | 1824 | page_add_new_anon_rmap(new_page, vma, address); |
1da177e4 | 1825 | |
945754a1 NP |
1826 | if (old_page) { |
1827 | /* | |
1828 | * Only after switching the pte to the new page may | |
1829 | * we remove the mapcount here. Otherwise another | |
1830 | * process may come and find the rmap count decremented | |
1831 | * before the pte is switched to the new page, and | |
1832 | * "reuse" the old page writing into it while our pte | |
1833 | * here still points into it and can be read by other | |
1834 | * threads. | |
1835 | * | |
1836 | * The critical issue is to order this | |
1837 | * page_remove_rmap with the ptp_clear_flush above. | |
1838 | * Those stores are ordered by (if nothing else,) | |
1839 | * the barrier present in the atomic_add_negative | |
1840 | * in page_remove_rmap. | |
1841 | * | |
1842 | * Then the TLB flush in ptep_clear_flush ensures that | |
1843 | * no process can access the old page before the | |
1844 | * decremented mapcount is visible. And the old page | |
1845 | * cannot be reused until after the decremented | |
1846 | * mapcount is visible. So transitively, TLBs to | |
1847 | * old page will be flushed before it can be reused. | |
1848 | */ | |
1849 | page_remove_rmap(old_page, vma); | |
1850 | } | |
1851 | ||
1da177e4 LT |
1852 | /* Free the old page.. */ |
1853 | new_page = old_page; | |
f33ea7f4 | 1854 | ret |= VM_FAULT_WRITE; |
8a9f3ccd BS |
1855 | } else |
1856 | mem_cgroup_uncharge_page(new_page); | |
1857 | ||
920fc356 HD |
1858 | if (new_page) |
1859 | page_cache_release(new_page); | |
1860 | if (old_page) | |
1861 | page_cache_release(old_page); | |
65500d23 | 1862 | unlock: |
8f4e2101 | 1863 | pte_unmap_unlock(page_table, ptl); |
d08b3851 | 1864 | if (dirty_page) { |
8f7b3d15 AS |
1865 | if (vma->vm_file) |
1866 | file_update_time(vma->vm_file); | |
1867 | ||
79352894 NP |
1868 | /* |
1869 | * Yes, Virginia, this is actually required to prevent a race | |
1870 | * with clear_page_dirty_for_io() from clearing the page dirty | |
1871 | * bit after it clear all dirty ptes, but before a racing | |
1872 | * do_wp_page installs a dirty pte. | |
1873 | * | |
1874 | * do_no_page is protected similarly. | |
1875 | */ | |
1876 | wait_on_page_locked(dirty_page); | |
a200ee18 | 1877 | set_page_dirty_balance(dirty_page, page_mkwrite); |
d08b3851 PZ |
1878 | put_page(dirty_page); |
1879 | } | |
f33ea7f4 | 1880 | return ret; |
8a9f3ccd | 1881 | oom_free_new: |
6dbf6d3b | 1882 | page_cache_release(new_page); |
65500d23 | 1883 | oom: |
920fc356 HD |
1884 | if (old_page) |
1885 | page_cache_release(old_page); | |
1da177e4 | 1886 | return VM_FAULT_OOM; |
9637a5ef DH |
1887 | |
1888 | unwritable_page: | |
1889 | page_cache_release(old_page); | |
1890 | return VM_FAULT_SIGBUS; | |
1da177e4 LT |
1891 | } |
1892 | ||
1893 | /* | |
1894 | * Helper functions for unmap_mapping_range(). | |
1895 | * | |
1896 | * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ | |
1897 | * | |
1898 | * We have to restart searching the prio_tree whenever we drop the lock, | |
1899 | * since the iterator is only valid while the lock is held, and anyway | |
1900 | * a later vma might be split and reinserted earlier while lock dropped. | |
1901 | * | |
1902 | * The list of nonlinear vmas could be handled more efficiently, using | |
1903 | * a placeholder, but handle it in the same way until a need is shown. | |
1904 | * It is important to search the prio_tree before nonlinear list: a vma | |
1905 | * may become nonlinear and be shifted from prio_tree to nonlinear list | |
1906 | * while the lock is dropped; but never shifted from list to prio_tree. | |
1907 | * | |
1908 | * In order to make forward progress despite restarting the search, | |
1909 | * vm_truncate_count is used to mark a vma as now dealt with, so we can | |
1910 | * quickly skip it next time around. Since the prio_tree search only | |
1911 | * shows us those vmas affected by unmapping the range in question, we | |
1912 | * can't efficiently keep all vmas in step with mapping->truncate_count: | |
1913 | * so instead reset them all whenever it wraps back to 0 (then go to 1). | |
1914 | * mapping->truncate_count and vma->vm_truncate_count are protected by | |
1915 | * i_mmap_lock. | |
1916 | * | |
1917 | * In order to make forward progress despite repeatedly restarting some | |
ee39b37b | 1918 | * large vma, note the restart_addr from unmap_vmas when it breaks out: |
1da177e4 LT |
1919 | * and restart from that address when we reach that vma again. It might |
1920 | * have been split or merged, shrunk or extended, but never shifted: so | |
1921 | * restart_addr remains valid so long as it remains in the vma's range. | |
1922 | * unmap_mapping_range forces truncate_count to leap over page-aligned | |
1923 | * values so we can save vma's restart_addr in its truncate_count field. | |
1924 | */ | |
1925 | #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) | |
1926 | ||
1927 | static void reset_vma_truncate_counts(struct address_space *mapping) | |
1928 | { | |
1929 | struct vm_area_struct *vma; | |
1930 | struct prio_tree_iter iter; | |
1931 | ||
1932 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) | |
1933 | vma->vm_truncate_count = 0; | |
1934 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) | |
1935 | vma->vm_truncate_count = 0; | |
1936 | } | |
1937 | ||
1938 | static int unmap_mapping_range_vma(struct vm_area_struct *vma, | |
1939 | unsigned long start_addr, unsigned long end_addr, | |
1940 | struct zap_details *details) | |
1941 | { | |
1942 | unsigned long restart_addr; | |
1943 | int need_break; | |
1944 | ||
d00806b1 NP |
1945 | /* |
1946 | * files that support invalidating or truncating portions of the | |
d0217ac0 | 1947 | * file from under mmaped areas must have their ->fault function |
83c54070 NP |
1948 | * return a locked page (and set VM_FAULT_LOCKED in the return). |
1949 | * This provides synchronisation against concurrent unmapping here. | |
d00806b1 | 1950 | */ |
d00806b1 | 1951 | |
1da177e4 LT |
1952 | again: |
1953 | restart_addr = vma->vm_truncate_count; | |
1954 | if (is_restart_addr(restart_addr) && start_addr < restart_addr) { | |
1955 | start_addr = restart_addr; | |
1956 | if (start_addr >= end_addr) { | |
1957 | /* Top of vma has been split off since last time */ | |
1958 | vma->vm_truncate_count = details->truncate_count; | |
1959 | return 0; | |
1960 | } | |
1961 | } | |
1962 | ||
ee39b37b HD |
1963 | restart_addr = zap_page_range(vma, start_addr, |
1964 | end_addr - start_addr, details); | |
95c354fe | 1965 | need_break = need_resched() || spin_needbreak(details->i_mmap_lock); |
1da177e4 | 1966 | |
ee39b37b | 1967 | if (restart_addr >= end_addr) { |
1da177e4 LT |
1968 | /* We have now completed this vma: mark it so */ |
1969 | vma->vm_truncate_count = details->truncate_count; | |
1970 | if (!need_break) | |
1971 | return 0; | |
1972 | } else { | |
1973 | /* Note restart_addr in vma's truncate_count field */ | |
ee39b37b | 1974 | vma->vm_truncate_count = restart_addr; |
1da177e4 LT |
1975 | if (!need_break) |
1976 | goto again; | |
1977 | } | |
1978 | ||
1979 | spin_unlock(details->i_mmap_lock); | |
1980 | cond_resched(); | |
1981 | spin_lock(details->i_mmap_lock); | |
1982 | return -EINTR; | |
1983 | } | |
1984 | ||
1985 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, | |
1986 | struct zap_details *details) | |
1987 | { | |
1988 | struct vm_area_struct *vma; | |
1989 | struct prio_tree_iter iter; | |
1990 | pgoff_t vba, vea, zba, zea; | |
1991 | ||
1992 | restart: | |
1993 | vma_prio_tree_foreach(vma, &iter, root, | |
1994 | details->first_index, details->last_index) { | |
1995 | /* Skip quickly over those we have already dealt with */ | |
1996 | if (vma->vm_truncate_count == details->truncate_count) | |
1997 | continue; | |
1998 | ||
1999 | vba = vma->vm_pgoff; | |
2000 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; | |
2001 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ | |
2002 | zba = details->first_index; | |
2003 | if (zba < vba) | |
2004 | zba = vba; | |
2005 | zea = details->last_index; | |
2006 | if (zea > vea) | |
2007 | zea = vea; | |
2008 | ||
2009 | if (unmap_mapping_range_vma(vma, | |
2010 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, | |
2011 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
2012 | details) < 0) | |
2013 | goto restart; | |
2014 | } | |
2015 | } | |
2016 | ||
2017 | static inline void unmap_mapping_range_list(struct list_head *head, | |
2018 | struct zap_details *details) | |
2019 | { | |
2020 | struct vm_area_struct *vma; | |
2021 | ||
2022 | /* | |
2023 | * In nonlinear VMAs there is no correspondence between virtual address | |
2024 | * offset and file offset. So we must perform an exhaustive search | |
2025 | * across *all* the pages in each nonlinear VMA, not just the pages | |
2026 | * whose virtual address lies outside the file truncation point. | |
2027 | */ | |
2028 | restart: | |
2029 | list_for_each_entry(vma, head, shared.vm_set.list) { | |
2030 | /* Skip quickly over those we have already dealt with */ | |
2031 | if (vma->vm_truncate_count == details->truncate_count) | |
2032 | continue; | |
2033 | details->nonlinear_vma = vma; | |
2034 | if (unmap_mapping_range_vma(vma, vma->vm_start, | |
2035 | vma->vm_end, details) < 0) | |
2036 | goto restart; | |
2037 | } | |
2038 | } | |
2039 | ||
2040 | /** | |
72fd4a35 | 2041 | * 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 | 2042 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
2043 | * @holebegin: byte in first page to unmap, relative to the start of |
2044 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
2045 | * boundary. Note that this is different from vmtruncate(), which | |
2046 | * must keep the partial page. In contrast, we must get rid of | |
2047 | * partial pages. | |
2048 | * @holelen: size of prospective hole in bytes. This will be rounded | |
2049 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
2050 | * end of the file. | |
2051 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
2052 | * but 0 when invalidating pagecache, don't throw away private data. | |
2053 | */ | |
2054 | void unmap_mapping_range(struct address_space *mapping, | |
2055 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
2056 | { | |
2057 | struct zap_details details; | |
2058 | pgoff_t hba = holebegin >> PAGE_SHIFT; | |
2059 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2060 | ||
2061 | /* Check for overflow. */ | |
2062 | if (sizeof(holelen) > sizeof(hlen)) { | |
2063 | long long holeend = | |
2064 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2065 | if (holeend & ~(long long)ULONG_MAX) | |
2066 | hlen = ULONG_MAX - hba + 1; | |
2067 | } | |
2068 | ||
2069 | details.check_mapping = even_cows? NULL: mapping; | |
2070 | details.nonlinear_vma = NULL; | |
2071 | details.first_index = hba; | |
2072 | details.last_index = hba + hlen - 1; | |
2073 | if (details.last_index < details.first_index) | |
2074 | details.last_index = ULONG_MAX; | |
2075 | details.i_mmap_lock = &mapping->i_mmap_lock; | |
2076 | ||
2077 | spin_lock(&mapping->i_mmap_lock); | |
2078 | ||
d00806b1 | 2079 | /* Protect against endless unmapping loops */ |
1da177e4 | 2080 | mapping->truncate_count++; |
1da177e4 LT |
2081 | if (unlikely(is_restart_addr(mapping->truncate_count))) { |
2082 | if (mapping->truncate_count == 0) | |
2083 | reset_vma_truncate_counts(mapping); | |
2084 | mapping->truncate_count++; | |
2085 | } | |
2086 | details.truncate_count = mapping->truncate_count; | |
2087 | ||
2088 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) | |
2089 | unmap_mapping_range_tree(&mapping->i_mmap, &details); | |
2090 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) | |
2091 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); | |
2092 | spin_unlock(&mapping->i_mmap_lock); | |
2093 | } | |
2094 | EXPORT_SYMBOL(unmap_mapping_range); | |
2095 | ||
bfa5bf6d REB |
2096 | /** |
2097 | * vmtruncate - unmap mappings "freed" by truncate() syscall | |
2098 | * @inode: inode of the file used | |
2099 | * @offset: file offset to start truncating | |
1da177e4 LT |
2100 | * |
2101 | * NOTE! We have to be ready to update the memory sharing | |
2102 | * between the file and the memory map for a potential last | |
2103 | * incomplete page. Ugly, but necessary. | |
2104 | */ | |
2105 | int vmtruncate(struct inode * inode, loff_t offset) | |
2106 | { | |
61d5048f CH |
2107 | if (inode->i_size < offset) { |
2108 | unsigned long limit; | |
2109 | ||
2110 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
2111 | if (limit != RLIM_INFINITY && offset > limit) | |
2112 | goto out_sig; | |
2113 | if (offset > inode->i_sb->s_maxbytes) | |
2114 | goto out_big; | |
2115 | i_size_write(inode, offset); | |
2116 | } else { | |
2117 | struct address_space *mapping = inode->i_mapping; | |
1da177e4 | 2118 | |
61d5048f CH |
2119 | /* |
2120 | * truncation of in-use swapfiles is disallowed - it would | |
2121 | * cause subsequent swapout to scribble on the now-freed | |
2122 | * blocks. | |
2123 | */ | |
2124 | if (IS_SWAPFILE(inode)) | |
2125 | return -ETXTBSY; | |
2126 | i_size_write(inode, offset); | |
2127 | ||
2128 | /* | |
2129 | * unmap_mapping_range is called twice, first simply for | |
2130 | * efficiency so that truncate_inode_pages does fewer | |
2131 | * single-page unmaps. However after this first call, and | |
2132 | * before truncate_inode_pages finishes, it is possible for | |
2133 | * private pages to be COWed, which remain after | |
2134 | * truncate_inode_pages finishes, hence the second | |
2135 | * unmap_mapping_range call must be made for correctness. | |
2136 | */ | |
2137 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
2138 | truncate_inode_pages(mapping, offset); | |
2139 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
2140 | } | |
d00806b1 | 2141 | |
1da177e4 LT |
2142 | if (inode->i_op && inode->i_op->truncate) |
2143 | inode->i_op->truncate(inode); | |
2144 | return 0; | |
61d5048f | 2145 | |
1da177e4 LT |
2146 | out_sig: |
2147 | send_sig(SIGXFSZ, current, 0); | |
2148 | out_big: | |
2149 | return -EFBIG; | |
1da177e4 | 2150 | } |
1da177e4 LT |
2151 | EXPORT_SYMBOL(vmtruncate); |
2152 | ||
f6b3ec23 BP |
2153 | int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) |
2154 | { | |
2155 | struct address_space *mapping = inode->i_mapping; | |
2156 | ||
2157 | /* | |
2158 | * If the underlying filesystem is not going to provide | |
2159 | * a way to truncate a range of blocks (punch a hole) - | |
2160 | * we should return failure right now. | |
2161 | */ | |
2162 | if (!inode->i_op || !inode->i_op->truncate_range) | |
2163 | return -ENOSYS; | |
2164 | ||
1b1dcc1b | 2165 | mutex_lock(&inode->i_mutex); |
f6b3ec23 BP |
2166 | down_write(&inode->i_alloc_sem); |
2167 | unmap_mapping_range(mapping, offset, (end - offset), 1); | |
2168 | truncate_inode_pages_range(mapping, offset, end); | |
d00806b1 | 2169 | unmap_mapping_range(mapping, offset, (end - offset), 1); |
f6b3ec23 BP |
2170 | inode->i_op->truncate_range(inode, offset, end); |
2171 | up_write(&inode->i_alloc_sem); | |
1b1dcc1b | 2172 | mutex_unlock(&inode->i_mutex); |
f6b3ec23 BP |
2173 | |
2174 | return 0; | |
2175 | } | |
f6b3ec23 | 2176 | |
1da177e4 | 2177 | /* |
8f4e2101 HD |
2178 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2179 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2180 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2181 | */ |
65500d23 HD |
2182 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2183 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2184 | int write_access, pte_t orig_pte) | |
1da177e4 | 2185 | { |
8f4e2101 | 2186 | spinlock_t *ptl; |
1da177e4 | 2187 | struct page *page; |
65500d23 | 2188 | swp_entry_t entry; |
1da177e4 | 2189 | pte_t pte; |
83c54070 | 2190 | int ret = 0; |
1da177e4 | 2191 | |
4c21e2f2 | 2192 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
8f4e2101 | 2193 | goto out; |
65500d23 HD |
2194 | |
2195 | entry = pte_to_swp_entry(orig_pte); | |
0697212a CL |
2196 | if (is_migration_entry(entry)) { |
2197 | migration_entry_wait(mm, pmd, address); | |
2198 | goto out; | |
2199 | } | |
0ff92245 | 2200 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2201 | page = lookup_swap_cache(entry); |
2202 | if (!page) { | |
098fe651 | 2203 | grab_swap_token(); /* Contend for token _before_ read-in */ |
02098fea HD |
2204 | page = swapin_readahead(entry, |
2205 | GFP_HIGHUSER_MOVABLE, vma, address); | |
1da177e4 LT |
2206 | if (!page) { |
2207 | /* | |
8f4e2101 HD |
2208 | * Back out if somebody else faulted in this pte |
2209 | * while we released the pte lock. | |
1da177e4 | 2210 | */ |
8f4e2101 | 2211 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2212 | if (likely(pte_same(*page_table, orig_pte))) |
2213 | ret = VM_FAULT_OOM; | |
0ff92245 | 2214 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2215 | goto unlock; |
1da177e4 LT |
2216 | } |
2217 | ||
2218 | /* Had to read the page from swap area: Major fault */ | |
2219 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2220 | count_vm_event(PGMAJFAULT); |
1da177e4 LT |
2221 | } |
2222 | ||
e1a1cd59 | 2223 | if (mem_cgroup_charge(page, mm, GFP_KERNEL)) { |
8a9f3ccd BS |
2224 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
2225 | ret = VM_FAULT_OOM; | |
2226 | goto out; | |
2227 | } | |
2228 | ||
1da177e4 LT |
2229 | mark_page_accessed(page); |
2230 | lock_page(page); | |
20a1022d | 2231 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2232 | |
2233 | /* | |
8f4e2101 | 2234 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 2235 | */ |
8f4e2101 | 2236 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
9e9bef07 | 2237 | if (unlikely(!pte_same(*page_table, orig_pte))) |
b8107480 | 2238 | goto out_nomap; |
b8107480 KK |
2239 | |
2240 | if (unlikely(!PageUptodate(page))) { | |
2241 | ret = VM_FAULT_SIGBUS; | |
2242 | goto out_nomap; | |
1da177e4 LT |
2243 | } |
2244 | ||
2245 | /* The page isn't present yet, go ahead with the fault. */ | |
1da177e4 | 2246 | |
4294621f | 2247 | inc_mm_counter(mm, anon_rss); |
1da177e4 LT |
2248 | pte = mk_pte(page, vma->vm_page_prot); |
2249 | if (write_access && can_share_swap_page(page)) { | |
2250 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); | |
2251 | write_access = 0; | |
2252 | } | |
1da177e4 LT |
2253 | |
2254 | flush_icache_page(vma, page); | |
2255 | set_pte_at(mm, address, page_table, pte); | |
2256 | page_add_anon_rmap(page, vma, address); | |
2257 | ||
c475a8ab HD |
2258 | swap_free(entry); |
2259 | if (vm_swap_full()) | |
2260 | remove_exclusive_swap_page(page); | |
2261 | unlock_page(page); | |
2262 | ||
1da177e4 | 2263 | if (write_access) { |
61469f1d HD |
2264 | ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); |
2265 | if (ret & VM_FAULT_ERROR) | |
2266 | ret &= VM_FAULT_ERROR; | |
1da177e4 LT |
2267 | goto out; |
2268 | } | |
2269 | ||
2270 | /* No need to invalidate - it was non-present before */ | |
2271 | update_mmu_cache(vma, address, pte); | |
65500d23 | 2272 | unlock: |
8f4e2101 | 2273 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2274 | out: |
2275 | return ret; | |
b8107480 | 2276 | out_nomap: |
8a9f3ccd | 2277 | mem_cgroup_uncharge_page(page); |
8f4e2101 | 2278 | pte_unmap_unlock(page_table, ptl); |
b8107480 KK |
2279 | unlock_page(page); |
2280 | page_cache_release(page); | |
65500d23 | 2281 | return ret; |
1da177e4 LT |
2282 | } |
2283 | ||
2284 | /* | |
8f4e2101 HD |
2285 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2286 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2287 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2288 | */ |
65500d23 HD |
2289 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2290 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2291 | int write_access) | |
1da177e4 | 2292 | { |
8f4e2101 HD |
2293 | struct page *page; |
2294 | spinlock_t *ptl; | |
1da177e4 | 2295 | pte_t entry; |
1da177e4 | 2296 | |
557ed1fa NP |
2297 | /* Allocate our own private page. */ |
2298 | pte_unmap(page_table); | |
8f4e2101 | 2299 | |
557ed1fa NP |
2300 | if (unlikely(anon_vma_prepare(vma))) |
2301 | goto oom; | |
2302 | page = alloc_zeroed_user_highpage_movable(vma, address); | |
2303 | if (!page) | |
2304 | goto oom; | |
0ed361de | 2305 | __SetPageUptodate(page); |
8f4e2101 | 2306 | |
e1a1cd59 | 2307 | if (mem_cgroup_charge(page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
2308 | goto oom_free_page; |
2309 | ||
557ed1fa NP |
2310 | entry = mk_pte(page, vma->vm_page_prot); |
2311 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1da177e4 | 2312 | |
557ed1fa NP |
2313 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
2314 | if (!pte_none(*page_table)) | |
2315 | goto release; | |
2316 | inc_mm_counter(mm, anon_rss); | |
2317 | lru_cache_add_active(page); | |
2318 | page_add_new_anon_rmap(page, vma, address); | |
65500d23 | 2319 | set_pte_at(mm, address, page_table, entry); |
1da177e4 LT |
2320 | |
2321 | /* No need to invalidate - it was non-present before */ | |
65500d23 | 2322 | update_mmu_cache(vma, address, entry); |
65500d23 | 2323 | unlock: |
8f4e2101 | 2324 | pte_unmap_unlock(page_table, ptl); |
83c54070 | 2325 | return 0; |
8f4e2101 | 2326 | release: |
8a9f3ccd | 2327 | mem_cgroup_uncharge_page(page); |
8f4e2101 HD |
2328 | page_cache_release(page); |
2329 | goto unlock; | |
8a9f3ccd | 2330 | oom_free_page: |
6dbf6d3b | 2331 | page_cache_release(page); |
65500d23 | 2332 | oom: |
1da177e4 LT |
2333 | return VM_FAULT_OOM; |
2334 | } | |
2335 | ||
2336 | /* | |
54cb8821 | 2337 | * __do_fault() tries to create a new page mapping. It aggressively |
1da177e4 | 2338 | * tries to share with existing pages, but makes a separate copy if |
54cb8821 NP |
2339 | * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid |
2340 | * the next page fault. | |
1da177e4 LT |
2341 | * |
2342 | * As this is called only for pages that do not currently exist, we | |
2343 | * do not need to flush old virtual caches or the TLB. | |
2344 | * | |
8f4e2101 | 2345 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
16abfa08 | 2346 | * but allow concurrent faults), and pte neither mapped nor locked. |
8f4e2101 | 2347 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
1da177e4 | 2348 | */ |
54cb8821 | 2349 | static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
16abfa08 | 2350 | unsigned long address, pmd_t *pmd, |
54cb8821 | 2351 | pgoff_t pgoff, unsigned int flags, pte_t orig_pte) |
1da177e4 | 2352 | { |
16abfa08 | 2353 | pte_t *page_table; |
8f4e2101 | 2354 | spinlock_t *ptl; |
d0217ac0 | 2355 | struct page *page; |
1da177e4 | 2356 | pte_t entry; |
1da177e4 | 2357 | int anon = 0; |
d08b3851 | 2358 | struct page *dirty_page = NULL; |
d0217ac0 NP |
2359 | struct vm_fault vmf; |
2360 | int ret; | |
a200ee18 | 2361 | int page_mkwrite = 0; |
54cb8821 | 2362 | |
d0217ac0 NP |
2363 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); |
2364 | vmf.pgoff = pgoff; | |
2365 | vmf.flags = flags; | |
2366 | vmf.page = NULL; | |
1da177e4 | 2367 | |
3c18ddd1 NP |
2368 | ret = vma->vm_ops->fault(vma, &vmf); |
2369 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) | |
2370 | return ret; | |
1da177e4 | 2371 | |
d00806b1 | 2372 | /* |
d0217ac0 | 2373 | * For consistency in subsequent calls, make the faulted page always |
d00806b1 NP |
2374 | * locked. |
2375 | */ | |
83c54070 | 2376 | if (unlikely(!(ret & VM_FAULT_LOCKED))) |
d0217ac0 | 2377 | lock_page(vmf.page); |
54cb8821 | 2378 | else |
d0217ac0 | 2379 | VM_BUG_ON(!PageLocked(vmf.page)); |
d00806b1 | 2380 | |
1da177e4 LT |
2381 | /* |
2382 | * Should we do an early C-O-W break? | |
2383 | */ | |
d0217ac0 | 2384 | page = vmf.page; |
54cb8821 | 2385 | if (flags & FAULT_FLAG_WRITE) { |
9637a5ef | 2386 | if (!(vma->vm_flags & VM_SHARED)) { |
54cb8821 | 2387 | anon = 1; |
d00806b1 | 2388 | if (unlikely(anon_vma_prepare(vma))) { |
d0217ac0 | 2389 | ret = VM_FAULT_OOM; |
54cb8821 | 2390 | goto out; |
d00806b1 | 2391 | } |
83c54070 NP |
2392 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, |
2393 | vma, address); | |
d00806b1 | 2394 | if (!page) { |
d0217ac0 | 2395 | ret = VM_FAULT_OOM; |
54cb8821 | 2396 | goto out; |
d00806b1 | 2397 | } |
d0217ac0 | 2398 | copy_user_highpage(page, vmf.page, address, vma); |
0ed361de | 2399 | __SetPageUptodate(page); |
9637a5ef | 2400 | } else { |
54cb8821 NP |
2401 | /* |
2402 | * If the page will be shareable, see if the backing | |
9637a5ef | 2403 | * address space wants to know that the page is about |
54cb8821 NP |
2404 | * to become writable |
2405 | */ | |
69676147 MF |
2406 | if (vma->vm_ops->page_mkwrite) { |
2407 | unlock_page(page); | |
2408 | if (vma->vm_ops->page_mkwrite(vma, page) < 0) { | |
d0217ac0 NP |
2409 | ret = VM_FAULT_SIGBUS; |
2410 | anon = 1; /* no anon but release vmf.page */ | |
69676147 MF |
2411 | goto out_unlocked; |
2412 | } | |
2413 | lock_page(page); | |
d0217ac0 NP |
2414 | /* |
2415 | * XXX: this is not quite right (racy vs | |
2416 | * invalidate) to unlock and relock the page | |
2417 | * like this, however a better fix requires | |
2418 | * reworking page_mkwrite locking API, which | |
2419 | * is better done later. | |
2420 | */ | |
2421 | if (!page->mapping) { | |
83c54070 | 2422 | ret = 0; |
d0217ac0 NP |
2423 | anon = 1; /* no anon but release vmf.page */ |
2424 | goto out; | |
2425 | } | |
a200ee18 | 2426 | page_mkwrite = 1; |
9637a5ef DH |
2427 | } |
2428 | } | |
54cb8821 | 2429 | |
1da177e4 LT |
2430 | } |
2431 | ||
e1a1cd59 | 2432 | if (mem_cgroup_charge(page, mm, GFP_KERNEL)) { |
8a9f3ccd BS |
2433 | ret = VM_FAULT_OOM; |
2434 | goto out; | |
2435 | } | |
2436 | ||
8f4e2101 | 2437 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2438 | |
2439 | /* | |
2440 | * This silly early PAGE_DIRTY setting removes a race | |
2441 | * due to the bad i386 page protection. But it's valid | |
2442 | * for other architectures too. | |
2443 | * | |
2444 | * Note that if write_access is true, we either now have | |
2445 | * an exclusive copy of the page, or this is a shared mapping, | |
2446 | * so we can make it writable and dirty to avoid having to | |
2447 | * handle that later. | |
2448 | */ | |
2449 | /* Only go through if we didn't race with anybody else... */ | |
54cb8821 | 2450 | if (likely(pte_same(*page_table, orig_pte))) { |
d00806b1 NP |
2451 | flush_icache_page(vma, page); |
2452 | entry = mk_pte(page, vma->vm_page_prot); | |
54cb8821 | 2453 | if (flags & FAULT_FLAG_WRITE) |
1da177e4 LT |
2454 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
2455 | set_pte_at(mm, address, page_table, entry); | |
2456 | if (anon) { | |
d00806b1 NP |
2457 | inc_mm_counter(mm, anon_rss); |
2458 | lru_cache_add_active(page); | |
2459 | page_add_new_anon_rmap(page, vma, address); | |
f57e88a8 | 2460 | } else { |
4294621f | 2461 | inc_mm_counter(mm, file_rss); |
d00806b1 | 2462 | page_add_file_rmap(page); |
54cb8821 | 2463 | if (flags & FAULT_FLAG_WRITE) { |
d00806b1 | 2464 | dirty_page = page; |
d08b3851 PZ |
2465 | get_page(dirty_page); |
2466 | } | |
4294621f | 2467 | } |
d00806b1 NP |
2468 | |
2469 | /* no need to invalidate: a not-present page won't be cached */ | |
2470 | update_mmu_cache(vma, address, entry); | |
1da177e4 | 2471 | } else { |
8a9f3ccd | 2472 | mem_cgroup_uncharge_page(page); |
d00806b1 NP |
2473 | if (anon) |
2474 | page_cache_release(page); | |
2475 | else | |
54cb8821 | 2476 | anon = 1; /* no anon but release faulted_page */ |
1da177e4 LT |
2477 | } |
2478 | ||
8f4e2101 | 2479 | pte_unmap_unlock(page_table, ptl); |
d00806b1 NP |
2480 | |
2481 | out: | |
d0217ac0 | 2482 | unlock_page(vmf.page); |
69676147 | 2483 | out_unlocked: |
d00806b1 | 2484 | if (anon) |
d0217ac0 | 2485 | page_cache_release(vmf.page); |
d00806b1 | 2486 | else if (dirty_page) { |
8f7b3d15 AS |
2487 | if (vma->vm_file) |
2488 | file_update_time(vma->vm_file); | |
2489 | ||
a200ee18 | 2490 | set_page_dirty_balance(dirty_page, page_mkwrite); |
d08b3851 PZ |
2491 | put_page(dirty_page); |
2492 | } | |
d00806b1 | 2493 | |
83c54070 | 2494 | return ret; |
54cb8821 | 2495 | } |
d00806b1 | 2496 | |
54cb8821 NP |
2497 | static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
2498 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2499 | int write_access, pte_t orig_pte) | |
2500 | { | |
2501 | pgoff_t pgoff = (((address & PAGE_MASK) | |
0da7e01f | 2502 | - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
54cb8821 NP |
2503 | unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0); |
2504 | ||
16abfa08 HD |
2505 | pte_unmap(page_table); |
2506 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); | |
54cb8821 NP |
2507 | } |
2508 | ||
1da177e4 LT |
2509 | /* |
2510 | * Fault of a previously existing named mapping. Repopulate the pte | |
2511 | * from the encoded file_pte if possible. This enables swappable | |
2512 | * nonlinear vmas. | |
8f4e2101 HD |
2513 | * |
2514 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
2515 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2516 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2517 | */ |
d0217ac0 | 2518 | static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
65500d23 HD |
2519 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
2520 | int write_access, pte_t orig_pte) | |
1da177e4 | 2521 | { |
d0217ac0 NP |
2522 | unsigned int flags = FAULT_FLAG_NONLINEAR | |
2523 | (write_access ? FAULT_FLAG_WRITE : 0); | |
65500d23 | 2524 | pgoff_t pgoff; |
1da177e4 | 2525 | |
4c21e2f2 | 2526 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
83c54070 | 2527 | return 0; |
1da177e4 | 2528 | |
d0217ac0 NP |
2529 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR) || |
2530 | !(vma->vm_flags & VM_CAN_NONLINEAR))) { | |
65500d23 HD |
2531 | /* |
2532 | * Page table corrupted: show pte and kill process. | |
2533 | */ | |
b5810039 | 2534 | print_bad_pte(vma, orig_pte, address); |
65500d23 HD |
2535 | return VM_FAULT_OOM; |
2536 | } | |
65500d23 HD |
2537 | |
2538 | pgoff = pte_to_pgoff(orig_pte); | |
16abfa08 | 2539 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); |
1da177e4 LT |
2540 | } |
2541 | ||
2542 | /* | |
2543 | * These routines also need to handle stuff like marking pages dirty | |
2544 | * and/or accessed for architectures that don't do it in hardware (most | |
2545 | * RISC architectures). The early dirtying is also good on the i386. | |
2546 | * | |
2547 | * There is also a hook called "update_mmu_cache()" that architectures | |
2548 | * with external mmu caches can use to update those (ie the Sparc or | |
2549 | * PowerPC hashed page tables that act as extended TLBs). | |
2550 | * | |
c74df32c HD |
2551 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2552 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2553 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 LT |
2554 | */ |
2555 | static inline int handle_pte_fault(struct mm_struct *mm, | |
65500d23 HD |
2556 | struct vm_area_struct *vma, unsigned long address, |
2557 | pte_t *pte, pmd_t *pmd, int write_access) | |
1da177e4 LT |
2558 | { |
2559 | pte_t entry; | |
8f4e2101 | 2560 | spinlock_t *ptl; |
1da177e4 | 2561 | |
8dab5241 | 2562 | entry = *pte; |
1da177e4 | 2563 | if (!pte_present(entry)) { |
65500d23 | 2564 | if (pte_none(entry)) { |
f4b81804 | 2565 | if (vma->vm_ops) { |
3c18ddd1 | 2566 | if (likely(vma->vm_ops->fault)) |
54cb8821 NP |
2567 | return do_linear_fault(mm, vma, address, |
2568 | pte, pmd, write_access, entry); | |
f4b81804 JS |
2569 | } |
2570 | return do_anonymous_page(mm, vma, address, | |
2571 | pte, pmd, write_access); | |
65500d23 | 2572 | } |
1da177e4 | 2573 | if (pte_file(entry)) |
d0217ac0 | 2574 | return do_nonlinear_fault(mm, vma, address, |
65500d23 HD |
2575 | pte, pmd, write_access, entry); |
2576 | return do_swap_page(mm, vma, address, | |
2577 | pte, pmd, write_access, entry); | |
1da177e4 LT |
2578 | } |
2579 | ||
4c21e2f2 | 2580 | ptl = pte_lockptr(mm, pmd); |
8f4e2101 HD |
2581 | spin_lock(ptl); |
2582 | if (unlikely(!pte_same(*pte, entry))) | |
2583 | goto unlock; | |
1da177e4 LT |
2584 | if (write_access) { |
2585 | if (!pte_write(entry)) | |
8f4e2101 HD |
2586 | return do_wp_page(mm, vma, address, |
2587 | pte, pmd, ptl, entry); | |
1da177e4 LT |
2588 | entry = pte_mkdirty(entry); |
2589 | } | |
2590 | entry = pte_mkyoung(entry); | |
8dab5241 | 2591 | if (ptep_set_access_flags(vma, address, pte, entry, write_access)) { |
1a44e149 | 2592 | update_mmu_cache(vma, address, entry); |
1a44e149 AA |
2593 | } else { |
2594 | /* | |
2595 | * This is needed only for protection faults but the arch code | |
2596 | * is not yet telling us if this is a protection fault or not. | |
2597 | * This still avoids useless tlb flushes for .text page faults | |
2598 | * with threads. | |
2599 | */ | |
2600 | if (write_access) | |
2601 | flush_tlb_page(vma, address); | |
2602 | } | |
8f4e2101 HD |
2603 | unlock: |
2604 | pte_unmap_unlock(pte, ptl); | |
83c54070 | 2605 | return 0; |
1da177e4 LT |
2606 | } |
2607 | ||
2608 | /* | |
2609 | * By the time we get here, we already hold the mm semaphore | |
2610 | */ | |
83c54070 | 2611 | int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
1da177e4 LT |
2612 | unsigned long address, int write_access) |
2613 | { | |
2614 | pgd_t *pgd; | |
2615 | pud_t *pud; | |
2616 | pmd_t *pmd; | |
2617 | pte_t *pte; | |
2618 | ||
2619 | __set_current_state(TASK_RUNNING); | |
2620 | ||
f8891e5e | 2621 | count_vm_event(PGFAULT); |
1da177e4 | 2622 | |
ac9b9c66 HD |
2623 | if (unlikely(is_vm_hugetlb_page(vma))) |
2624 | return hugetlb_fault(mm, vma, address, write_access); | |
1da177e4 | 2625 | |
1da177e4 | 2626 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
2627 | pud = pud_alloc(mm, pgd, address); |
2628 | if (!pud) | |
c74df32c | 2629 | return VM_FAULT_OOM; |
1da177e4 LT |
2630 | pmd = pmd_alloc(mm, pud, address); |
2631 | if (!pmd) | |
c74df32c | 2632 | return VM_FAULT_OOM; |
1da177e4 LT |
2633 | pte = pte_alloc_map(mm, pmd, address); |
2634 | if (!pte) | |
c74df32c | 2635 | return VM_FAULT_OOM; |
1da177e4 | 2636 | |
c74df32c | 2637 | return handle_pte_fault(mm, vma, address, pte, pmd, write_access); |
1da177e4 LT |
2638 | } |
2639 | ||
2640 | #ifndef __PAGETABLE_PUD_FOLDED | |
2641 | /* | |
2642 | * Allocate page upper directory. | |
872fec16 | 2643 | * We've already handled the fast-path in-line. |
1da177e4 | 2644 | */ |
1bb3630e | 2645 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 2646 | { |
c74df32c HD |
2647 | pud_t *new = pud_alloc_one(mm, address); |
2648 | if (!new) | |
1bb3630e | 2649 | return -ENOMEM; |
1da177e4 | 2650 | |
362a61ad NP |
2651 | smp_wmb(); /* See comment in __pte_alloc */ |
2652 | ||
872fec16 | 2653 | spin_lock(&mm->page_table_lock); |
1bb3630e | 2654 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 2655 | pud_free(mm, new); |
1bb3630e HD |
2656 | else |
2657 | pgd_populate(mm, pgd, new); | |
c74df32c | 2658 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 2659 | return 0; |
1da177e4 LT |
2660 | } |
2661 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
2662 | ||
2663 | #ifndef __PAGETABLE_PMD_FOLDED | |
2664 | /* | |
2665 | * Allocate page middle directory. | |
872fec16 | 2666 | * We've already handled the fast-path in-line. |
1da177e4 | 2667 | */ |
1bb3630e | 2668 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 2669 | { |
c74df32c HD |
2670 | pmd_t *new = pmd_alloc_one(mm, address); |
2671 | if (!new) | |
1bb3630e | 2672 | return -ENOMEM; |
1da177e4 | 2673 | |
362a61ad NP |
2674 | smp_wmb(); /* See comment in __pte_alloc */ |
2675 | ||
872fec16 | 2676 | spin_lock(&mm->page_table_lock); |
1da177e4 | 2677 | #ifndef __ARCH_HAS_4LEVEL_HACK |
1bb3630e | 2678 | if (pud_present(*pud)) /* Another has populated it */ |
5e541973 | 2679 | pmd_free(mm, new); |
1bb3630e HD |
2680 | else |
2681 | pud_populate(mm, pud, new); | |
1da177e4 | 2682 | #else |
1bb3630e | 2683 | if (pgd_present(*pud)) /* Another has populated it */ |
5e541973 | 2684 | pmd_free(mm, new); |
1bb3630e HD |
2685 | else |
2686 | pgd_populate(mm, pud, new); | |
1da177e4 | 2687 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 2688 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 2689 | return 0; |
e0f39591 | 2690 | } |
1da177e4 LT |
2691 | #endif /* __PAGETABLE_PMD_FOLDED */ |
2692 | ||
2693 | int make_pages_present(unsigned long addr, unsigned long end) | |
2694 | { | |
2695 | int ret, len, write; | |
2696 | struct vm_area_struct * vma; | |
2697 | ||
2698 | vma = find_vma(current->mm, addr); | |
2699 | if (!vma) | |
2700 | return -1; | |
2701 | write = (vma->vm_flags & VM_WRITE) != 0; | |
5bcb28b1 ES |
2702 | BUG_ON(addr >= end); |
2703 | BUG_ON(end > vma->vm_end); | |
68e116a3 | 2704 | len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; |
1da177e4 LT |
2705 | ret = get_user_pages(current, current->mm, addr, |
2706 | len, write, 0, NULL, NULL); | |
2707 | if (ret < 0) | |
2708 | return ret; | |
2709 | return ret == len ? 0 : -1; | |
2710 | } | |
2711 | ||
1da177e4 LT |
2712 | #if !defined(__HAVE_ARCH_GATE_AREA) |
2713 | ||
2714 | #if defined(AT_SYSINFO_EHDR) | |
5ce7852c | 2715 | static struct vm_area_struct gate_vma; |
1da177e4 LT |
2716 | |
2717 | static int __init gate_vma_init(void) | |
2718 | { | |
2719 | gate_vma.vm_mm = NULL; | |
2720 | gate_vma.vm_start = FIXADDR_USER_START; | |
2721 | gate_vma.vm_end = FIXADDR_USER_END; | |
b6558c4a RM |
2722 | gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; |
2723 | gate_vma.vm_page_prot = __P101; | |
f47aef55 RM |
2724 | /* |
2725 | * Make sure the vDSO gets into every core dump. | |
2726 | * Dumping its contents makes post-mortem fully interpretable later | |
2727 | * without matching up the same kernel and hardware config to see | |
2728 | * what PC values meant. | |
2729 | */ | |
2730 | gate_vma.vm_flags |= VM_ALWAYSDUMP; | |
1da177e4 LT |
2731 | return 0; |
2732 | } | |
2733 | __initcall(gate_vma_init); | |
2734 | #endif | |
2735 | ||
2736 | struct vm_area_struct *get_gate_vma(struct task_struct *tsk) | |
2737 | { | |
2738 | #ifdef AT_SYSINFO_EHDR | |
2739 | return &gate_vma; | |
2740 | #else | |
2741 | return NULL; | |
2742 | #endif | |
2743 | } | |
2744 | ||
2745 | int in_gate_area_no_task(unsigned long addr) | |
2746 | { | |
2747 | #ifdef AT_SYSINFO_EHDR | |
2748 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) | |
2749 | return 1; | |
2750 | #endif | |
2751 | return 0; | |
2752 | } | |
2753 | ||
2754 | #endif /* __HAVE_ARCH_GATE_AREA */ | |
0ec76a11 | 2755 | |
28b2ee20 RR |
2756 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
2757 | static resource_size_t follow_phys(struct vm_area_struct *vma, | |
2758 | unsigned long address, unsigned int flags, | |
2759 | unsigned long *prot) | |
2760 | { | |
2761 | pgd_t *pgd; | |
2762 | pud_t *pud; | |
2763 | pmd_t *pmd; | |
2764 | pte_t *ptep, pte; | |
2765 | spinlock_t *ptl; | |
2766 | resource_size_t phys_addr = 0; | |
2767 | struct mm_struct *mm = vma->vm_mm; | |
2768 | ||
2769 | VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP))); | |
2770 | ||
2771 | pgd = pgd_offset(mm, address); | |
2772 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
2773 | goto no_page_table; | |
2774 | ||
2775 | pud = pud_offset(pgd, address); | |
2776 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
2777 | goto no_page_table; | |
2778 | ||
2779 | pmd = pmd_offset(pud, address); | |
2780 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
2781 | goto no_page_table; | |
2782 | ||
2783 | /* We cannot handle huge page PFN maps. Luckily they don't exist. */ | |
2784 | if (pmd_huge(*pmd)) | |
2785 | goto no_page_table; | |
2786 | ||
2787 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2788 | if (!ptep) | |
2789 | goto out; | |
2790 | ||
2791 | pte = *ptep; | |
2792 | if (!pte_present(pte)) | |
2793 | goto unlock; | |
2794 | if ((flags & FOLL_WRITE) && !pte_write(pte)) | |
2795 | goto unlock; | |
2796 | phys_addr = pte_pfn(pte); | |
2797 | phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */ | |
2798 | ||
2799 | *prot = pgprot_val(pte_pgprot(pte)); | |
2800 | ||
2801 | unlock: | |
2802 | pte_unmap_unlock(ptep, ptl); | |
2803 | out: | |
2804 | return phys_addr; | |
2805 | no_page_table: | |
2806 | return 0; | |
2807 | } | |
2808 | ||
2809 | int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, | |
2810 | void *buf, int len, int write) | |
2811 | { | |
2812 | resource_size_t phys_addr; | |
2813 | unsigned long prot = 0; | |
2814 | void *maddr; | |
2815 | int offset = addr & (PAGE_SIZE-1); | |
2816 | ||
2817 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
2818 | return -EINVAL; | |
2819 | ||
2820 | phys_addr = follow_phys(vma, addr, write, &prot); | |
2821 | ||
2822 | if (!phys_addr) | |
2823 | return -EINVAL; | |
2824 | ||
2825 | maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); | |
2826 | if (write) | |
2827 | memcpy_toio(maddr + offset, buf, len); | |
2828 | else | |
2829 | memcpy_fromio(buf, maddr + offset, len); | |
2830 | iounmap(maddr); | |
2831 | ||
2832 | return len; | |
2833 | } | |
2834 | #endif | |
2835 | ||
0ec76a11 DH |
2836 | /* |
2837 | * Access another process' address space. | |
2838 | * Source/target buffer must be kernel space, | |
2839 | * Do not walk the page table directly, use get_user_pages | |
2840 | */ | |
2841 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
2842 | { | |
2843 | struct mm_struct *mm; | |
2844 | struct vm_area_struct *vma; | |
0ec76a11 DH |
2845 | void *old_buf = buf; |
2846 | ||
2847 | mm = get_task_mm(tsk); | |
2848 | if (!mm) | |
2849 | return 0; | |
2850 | ||
2851 | down_read(&mm->mmap_sem); | |
183ff22b | 2852 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
2853 | while (len) { |
2854 | int bytes, ret, offset; | |
2855 | void *maddr; | |
28b2ee20 | 2856 | struct page *page = NULL; |
0ec76a11 DH |
2857 | |
2858 | ret = get_user_pages(tsk, mm, addr, 1, | |
2859 | write, 1, &page, &vma); | |
28b2ee20 RR |
2860 | if (ret <= 0) { |
2861 | /* | |
2862 | * Check if this is a VM_IO | VM_PFNMAP VMA, which | |
2863 | * we can access using slightly different code. | |
2864 | */ | |
2865 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
2866 | vma = find_vma(mm, addr); | |
2867 | if (!vma) | |
2868 | break; | |
2869 | if (vma->vm_ops && vma->vm_ops->access) | |
2870 | ret = vma->vm_ops->access(vma, addr, buf, | |
2871 | len, write); | |
2872 | if (ret <= 0) | |
2873 | #endif | |
2874 | break; | |
2875 | bytes = ret; | |
0ec76a11 | 2876 | } else { |
28b2ee20 RR |
2877 | bytes = len; |
2878 | offset = addr & (PAGE_SIZE-1); | |
2879 | if (bytes > PAGE_SIZE-offset) | |
2880 | bytes = PAGE_SIZE-offset; | |
2881 | ||
2882 | maddr = kmap(page); | |
2883 | if (write) { | |
2884 | copy_to_user_page(vma, page, addr, | |
2885 | maddr + offset, buf, bytes); | |
2886 | set_page_dirty_lock(page); | |
2887 | } else { | |
2888 | copy_from_user_page(vma, page, addr, | |
2889 | buf, maddr + offset, bytes); | |
2890 | } | |
2891 | kunmap(page); | |
2892 | page_cache_release(page); | |
0ec76a11 | 2893 | } |
0ec76a11 DH |
2894 | len -= bytes; |
2895 | buf += bytes; | |
2896 | addr += bytes; | |
2897 | } | |
2898 | up_read(&mm->mmap_sem); | |
2899 | mmput(mm); | |
2900 | ||
2901 | return buf - old_buf; | |
2902 | } | |
03252919 AK |
2903 | |
2904 | /* | |
2905 | * Print the name of a VMA. | |
2906 | */ | |
2907 | void print_vma_addr(char *prefix, unsigned long ip) | |
2908 | { | |
2909 | struct mm_struct *mm = current->mm; | |
2910 | struct vm_area_struct *vma; | |
2911 | ||
e8bff74a IM |
2912 | /* |
2913 | * Do not print if we are in atomic | |
2914 | * contexts (in exception stacks, etc.): | |
2915 | */ | |
2916 | if (preempt_count()) | |
2917 | return; | |
2918 | ||
03252919 AK |
2919 | down_read(&mm->mmap_sem); |
2920 | vma = find_vma(mm, ip); | |
2921 | if (vma && vma->vm_file) { | |
2922 | struct file *f = vma->vm_file; | |
2923 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
2924 | if (buf) { | |
2925 | char *p, *s; | |
2926 | ||
cf28b486 | 2927 | p = d_path(&f->f_path, buf, PAGE_SIZE); |
03252919 AK |
2928 | if (IS_ERR(p)) |
2929 | p = "?"; | |
2930 | s = strrchr(p, '/'); | |
2931 | if (s) | |
2932 | p = s+1; | |
2933 | printk("%s%s[%lx+%lx]", prefix, p, | |
2934 | vma->vm_start, | |
2935 | vma->vm_end - vma->vm_start); | |
2936 | free_page((unsigned long)buf); | |
2937 | } | |
2938 | } | |
2939 | up_read(¤t->mm->mmap_sem); | |
2940 | } |