Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/mm/memory.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds | |
5 | */ | |
6 | ||
7 | /* | |
8 | * demand-loading started 01.12.91 - seems it is high on the list of | |
9 | * things wanted, and it should be easy to implement. - Linus | |
10 | */ | |
11 | ||
12 | /* | |
13 | * Ok, demand-loading was easy, shared pages a little bit tricker. Shared | |
14 | * pages started 02.12.91, seems to work. - Linus. | |
15 | * | |
16 | * Tested sharing by executing about 30 /bin/sh: under the old kernel it | |
17 | * would have taken more than the 6M I have free, but it worked well as | |
18 | * far as I could see. | |
19 | * | |
20 | * Also corrected some "invalidate()"s - I wasn't doing enough of them. | |
21 | */ | |
22 | ||
23 | /* | |
24 | * Real VM (paging to/from disk) started 18.12.91. Much more work and | |
25 | * thought has to go into this. Oh, well.. | |
26 | * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why. | |
27 | * Found it. Everything seems to work now. | |
28 | * 20.12.91 - Ok, making the swap-device changeable like the root. | |
29 | */ | |
30 | ||
31 | /* | |
32 | * 05.04.94 - Multi-page memory management added for v1.1. | |
33 | * Idea by Alex Bligh (alex@cconcepts.co.uk) | |
34 | * | |
35 | * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG | |
36 | * (Gerhard.Wichert@pdb.siemens.de) | |
37 | * | |
38 | * Aug/Sep 2004 Changed to four level page tables (Andi Kleen) | |
39 | */ | |
40 | ||
41 | #include <linux/kernel_stat.h> | |
42 | #include <linux/mm.h> | |
43 | #include <linux/hugetlb.h> | |
44 | #include <linux/mman.h> | |
45 | #include <linux/swap.h> | |
46 | #include <linux/highmem.h> | |
47 | #include <linux/pagemap.h> | |
48 | #include <linux/rmap.h> | |
49 | #include <linux/module.h> | |
0ff92245 | 50 | #include <linux/delayacct.h> |
1da177e4 | 51 | #include <linux/init.h> |
edc79b2a | 52 | #include <linux/writeback.h> |
8a9f3ccd | 53 | #include <linux/memcontrol.h> |
cddb8a5c | 54 | #include <linux/mmu_notifier.h> |
1da177e4 LT |
55 | |
56 | #include <asm/pgalloc.h> | |
57 | #include <asm/uaccess.h> | |
58 | #include <asm/tlb.h> | |
59 | #include <asm/tlbflush.h> | |
60 | #include <asm/pgtable.h> | |
61 | ||
62 | #include <linux/swapops.h> | |
63 | #include <linux/elf.h> | |
64 | ||
42b77728 JB |
65 | #include "internal.h" |
66 | ||
d41dee36 | 67 | #ifndef CONFIG_NEED_MULTIPLE_NODES |
1da177e4 LT |
68 | /* use the per-pgdat data instead for discontigmem - mbligh */ |
69 | unsigned long max_mapnr; | |
70 | struct page *mem_map; | |
71 | ||
72 | EXPORT_SYMBOL(max_mapnr); | |
73 | EXPORT_SYMBOL(mem_map); | |
74 | #endif | |
75 | ||
76 | unsigned long num_physpages; | |
77 | /* | |
78 | * A number of key systems in x86 including ioremap() rely on the assumption | |
79 | * that high_memory defines the upper bound on direct map memory, then end | |
80 | * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and | |
81 | * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL | |
82 | * and ZONE_HIGHMEM. | |
83 | */ | |
84 | void * high_memory; | |
1da177e4 LT |
85 | |
86 | EXPORT_SYMBOL(num_physpages); | |
87 | EXPORT_SYMBOL(high_memory); | |
1da177e4 | 88 | |
32a93233 IM |
89 | /* |
90 | * Randomize the address space (stacks, mmaps, brk, etc.). | |
91 | * | |
92 | * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization, | |
93 | * as ancient (libc5 based) binaries can segfault. ) | |
94 | */ | |
95 | int randomize_va_space __read_mostly = | |
96 | #ifdef CONFIG_COMPAT_BRK | |
97 | 1; | |
98 | #else | |
99 | 2; | |
100 | #endif | |
a62eaf15 AK |
101 | |
102 | static int __init disable_randmaps(char *s) | |
103 | { | |
104 | randomize_va_space = 0; | |
9b41046c | 105 | return 1; |
a62eaf15 AK |
106 | } |
107 | __setup("norandmaps", disable_randmaps); | |
108 | ||
109 | ||
1da177e4 LT |
110 | /* |
111 | * If a p?d_bad entry is found while walking page tables, report | |
112 | * the error, before resetting entry to p?d_none. Usually (but | |
113 | * very seldom) called out from the p?d_none_or_clear_bad macros. | |
114 | */ | |
115 | ||
116 | void pgd_clear_bad(pgd_t *pgd) | |
117 | { | |
118 | pgd_ERROR(*pgd); | |
119 | pgd_clear(pgd); | |
120 | } | |
121 | ||
122 | void pud_clear_bad(pud_t *pud) | |
123 | { | |
124 | pud_ERROR(*pud); | |
125 | pud_clear(pud); | |
126 | } | |
127 | ||
128 | void pmd_clear_bad(pmd_t *pmd) | |
129 | { | |
130 | pmd_ERROR(*pmd); | |
131 | pmd_clear(pmd); | |
132 | } | |
133 | ||
134 | /* | |
135 | * Note: this doesn't free the actual pages themselves. That | |
136 | * has been handled earlier when unmapping all the memory regions. | |
137 | */ | |
e0da382c | 138 | static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd) |
1da177e4 | 139 | { |
2f569afd | 140 | pgtable_t token = pmd_pgtable(*pmd); |
e0da382c | 141 | pmd_clear(pmd); |
2f569afd | 142 | pte_free_tlb(tlb, token); |
e0da382c | 143 | tlb->mm->nr_ptes--; |
1da177e4 LT |
144 | } |
145 | ||
e0da382c HD |
146 | static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud, |
147 | unsigned long addr, unsigned long end, | |
148 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
149 | { |
150 | pmd_t *pmd; | |
151 | unsigned long next; | |
e0da382c | 152 | unsigned long start; |
1da177e4 | 153 | |
e0da382c | 154 | start = addr; |
1da177e4 | 155 | pmd = pmd_offset(pud, addr); |
1da177e4 LT |
156 | do { |
157 | next = pmd_addr_end(addr, end); | |
158 | if (pmd_none_or_clear_bad(pmd)) | |
159 | continue; | |
e0da382c | 160 | free_pte_range(tlb, pmd); |
1da177e4 LT |
161 | } while (pmd++, addr = next, addr != end); |
162 | ||
e0da382c HD |
163 | start &= PUD_MASK; |
164 | if (start < floor) | |
165 | return; | |
166 | if (ceiling) { | |
167 | ceiling &= PUD_MASK; | |
168 | if (!ceiling) | |
169 | return; | |
1da177e4 | 170 | } |
e0da382c HD |
171 | if (end - 1 > ceiling - 1) |
172 | return; | |
173 | ||
174 | pmd = pmd_offset(pud, start); | |
175 | pud_clear(pud); | |
176 | pmd_free_tlb(tlb, pmd); | |
1da177e4 LT |
177 | } |
178 | ||
e0da382c HD |
179 | static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, |
180 | unsigned long addr, unsigned long end, | |
181 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
182 | { |
183 | pud_t *pud; | |
184 | unsigned long next; | |
e0da382c | 185 | unsigned long start; |
1da177e4 | 186 | |
e0da382c | 187 | start = addr; |
1da177e4 | 188 | pud = pud_offset(pgd, addr); |
1da177e4 LT |
189 | do { |
190 | next = pud_addr_end(addr, end); | |
191 | if (pud_none_or_clear_bad(pud)) | |
192 | continue; | |
e0da382c | 193 | free_pmd_range(tlb, pud, addr, next, floor, ceiling); |
1da177e4 LT |
194 | } while (pud++, addr = next, addr != end); |
195 | ||
e0da382c HD |
196 | start &= PGDIR_MASK; |
197 | if (start < floor) | |
198 | return; | |
199 | if (ceiling) { | |
200 | ceiling &= PGDIR_MASK; | |
201 | if (!ceiling) | |
202 | return; | |
1da177e4 | 203 | } |
e0da382c HD |
204 | if (end - 1 > ceiling - 1) |
205 | return; | |
206 | ||
207 | pud = pud_offset(pgd, start); | |
208 | pgd_clear(pgd); | |
209 | pud_free_tlb(tlb, pud); | |
1da177e4 LT |
210 | } |
211 | ||
212 | /* | |
e0da382c HD |
213 | * This function frees user-level page tables of a process. |
214 | * | |
1da177e4 LT |
215 | * Must be called with pagetable lock held. |
216 | */ | |
42b77728 | 217 | void free_pgd_range(struct mmu_gather *tlb, |
e0da382c HD |
218 | unsigned long addr, unsigned long end, |
219 | unsigned long floor, unsigned long ceiling) | |
1da177e4 LT |
220 | { |
221 | pgd_t *pgd; | |
222 | unsigned long next; | |
e0da382c HD |
223 | unsigned long start; |
224 | ||
225 | /* | |
226 | * The next few lines have given us lots of grief... | |
227 | * | |
228 | * Why are we testing PMD* at this top level? Because often | |
229 | * there will be no work to do at all, and we'd prefer not to | |
230 | * go all the way down to the bottom just to discover that. | |
231 | * | |
232 | * Why all these "- 1"s? Because 0 represents both the bottom | |
233 | * of the address space and the top of it (using -1 for the | |
234 | * top wouldn't help much: the masks would do the wrong thing). | |
235 | * The rule is that addr 0 and floor 0 refer to the bottom of | |
236 | * the address space, but end 0 and ceiling 0 refer to the top | |
237 | * Comparisons need to use "end - 1" and "ceiling - 1" (though | |
238 | * that end 0 case should be mythical). | |
239 | * | |
240 | * Wherever addr is brought up or ceiling brought down, we must | |
241 | * be careful to reject "the opposite 0" before it confuses the | |
242 | * subsequent tests. But what about where end is brought down | |
243 | * by PMD_SIZE below? no, end can't go down to 0 there. | |
244 | * | |
245 | * Whereas we round start (addr) and ceiling down, by different | |
246 | * masks at different levels, in order to test whether a table | |
247 | * now has no other vmas using it, so can be freed, we don't | |
248 | * bother to round floor or end up - the tests don't need that. | |
249 | */ | |
1da177e4 | 250 | |
e0da382c HD |
251 | addr &= PMD_MASK; |
252 | if (addr < floor) { | |
253 | addr += PMD_SIZE; | |
254 | if (!addr) | |
255 | return; | |
256 | } | |
257 | if (ceiling) { | |
258 | ceiling &= PMD_MASK; | |
259 | if (!ceiling) | |
260 | return; | |
261 | } | |
262 | if (end - 1 > ceiling - 1) | |
263 | end -= PMD_SIZE; | |
264 | if (addr > end - 1) | |
265 | return; | |
266 | ||
267 | start = addr; | |
42b77728 | 268 | pgd = pgd_offset(tlb->mm, addr); |
1da177e4 LT |
269 | do { |
270 | next = pgd_addr_end(addr, end); | |
271 | if (pgd_none_or_clear_bad(pgd)) | |
272 | continue; | |
42b77728 | 273 | free_pud_range(tlb, pgd, addr, next, floor, ceiling); |
1da177e4 | 274 | } while (pgd++, addr = next, addr != end); |
e0da382c HD |
275 | } |
276 | ||
42b77728 | 277 | void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma, |
3bf5ee95 | 278 | unsigned long floor, unsigned long ceiling) |
e0da382c HD |
279 | { |
280 | while (vma) { | |
281 | struct vm_area_struct *next = vma->vm_next; | |
282 | unsigned long addr = vma->vm_start; | |
283 | ||
8f4f8c16 HD |
284 | /* |
285 | * Hide vma from rmap and vmtruncate before freeing pgtables | |
286 | */ | |
287 | anon_vma_unlink(vma); | |
288 | unlink_file_vma(vma); | |
289 | ||
9da61aef | 290 | if (is_vm_hugetlb_page(vma)) { |
3bf5ee95 | 291 | hugetlb_free_pgd_range(tlb, addr, vma->vm_end, |
e0da382c | 292 | floor, next? next->vm_start: ceiling); |
3bf5ee95 HD |
293 | } else { |
294 | /* | |
295 | * Optimization: gather nearby vmas into one call down | |
296 | */ | |
297 | while (next && next->vm_start <= vma->vm_end + PMD_SIZE | |
4866920b | 298 | && !is_vm_hugetlb_page(next)) { |
3bf5ee95 HD |
299 | vma = next; |
300 | next = vma->vm_next; | |
8f4f8c16 HD |
301 | anon_vma_unlink(vma); |
302 | unlink_file_vma(vma); | |
3bf5ee95 HD |
303 | } |
304 | free_pgd_range(tlb, addr, vma->vm_end, | |
305 | floor, next? next->vm_start: ceiling); | |
306 | } | |
e0da382c HD |
307 | vma = next; |
308 | } | |
1da177e4 LT |
309 | } |
310 | ||
1bb3630e | 311 | int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address) |
1da177e4 | 312 | { |
2f569afd | 313 | pgtable_t new = pte_alloc_one(mm, address); |
1bb3630e HD |
314 | if (!new) |
315 | return -ENOMEM; | |
316 | ||
362a61ad NP |
317 | /* |
318 | * Ensure all pte setup (eg. pte page lock and page clearing) are | |
319 | * visible before the pte is made visible to other CPUs by being | |
320 | * put into page tables. | |
321 | * | |
322 | * The other side of the story is the pointer chasing in the page | |
323 | * table walking code (when walking the page table without locking; | |
324 | * ie. most of the time). Fortunately, these data accesses consist | |
325 | * of a chain of data-dependent loads, meaning most CPUs (alpha | |
326 | * being the notable exception) will already guarantee loads are | |
327 | * seen in-order. See the alpha page table accessors for the | |
328 | * smp_read_barrier_depends() barriers in page table walking code. | |
329 | */ | |
330 | smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ | |
331 | ||
c74df32c | 332 | spin_lock(&mm->page_table_lock); |
2f569afd | 333 | if (!pmd_present(*pmd)) { /* Has another populated it ? */ |
1da177e4 | 334 | mm->nr_ptes++; |
1da177e4 | 335 | pmd_populate(mm, pmd, new); |
2f569afd | 336 | new = NULL; |
1da177e4 | 337 | } |
c74df32c | 338 | spin_unlock(&mm->page_table_lock); |
2f569afd MS |
339 | if (new) |
340 | pte_free(mm, new); | |
1bb3630e | 341 | return 0; |
1da177e4 LT |
342 | } |
343 | ||
1bb3630e | 344 | int __pte_alloc_kernel(pmd_t *pmd, unsigned long address) |
1da177e4 | 345 | { |
1bb3630e HD |
346 | pte_t *new = pte_alloc_one_kernel(&init_mm, address); |
347 | if (!new) | |
348 | return -ENOMEM; | |
349 | ||
362a61ad NP |
350 | smp_wmb(); /* See comment in __pte_alloc */ |
351 | ||
1bb3630e | 352 | spin_lock(&init_mm.page_table_lock); |
2f569afd | 353 | if (!pmd_present(*pmd)) { /* Has another populated it ? */ |
1bb3630e | 354 | pmd_populate_kernel(&init_mm, pmd, new); |
2f569afd MS |
355 | new = NULL; |
356 | } | |
1bb3630e | 357 | spin_unlock(&init_mm.page_table_lock); |
2f569afd MS |
358 | if (new) |
359 | pte_free_kernel(&init_mm, new); | |
1bb3630e | 360 | return 0; |
1da177e4 LT |
361 | } |
362 | ||
ae859762 HD |
363 | static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss) |
364 | { | |
365 | if (file_rss) | |
366 | add_mm_counter(mm, file_rss, file_rss); | |
367 | if (anon_rss) | |
368 | add_mm_counter(mm, anon_rss, anon_rss); | |
369 | } | |
370 | ||
b5810039 | 371 | /* |
6aab341e LT |
372 | * This function is called to print an error when a bad pte |
373 | * is found. For example, we might have a PFN-mapped pte in | |
374 | * a region that doesn't allow it. | |
b5810039 NP |
375 | * |
376 | * The calling function must still handle the error. | |
377 | */ | |
15f59ada AB |
378 | static void print_bad_pte(struct vm_area_struct *vma, pte_t pte, |
379 | unsigned long vaddr) | |
b5810039 NP |
380 | { |
381 | printk(KERN_ERR "Bad pte = %08llx, process = %s, " | |
382 | "vm_flags = %lx, vaddr = %lx\n", | |
383 | (long long)pte_val(pte), | |
384 | (vma->vm_mm == current->mm ? current->comm : "???"), | |
385 | vma->vm_flags, vaddr); | |
386 | dump_stack(); | |
387 | } | |
388 | ||
67121172 LT |
389 | static inline int is_cow_mapping(unsigned int flags) |
390 | { | |
391 | return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; | |
392 | } | |
393 | ||
ee498ed7 | 394 | /* |
7e675137 | 395 | * vm_normal_page -- This function gets the "struct page" associated with a pte. |
6aab341e | 396 | * |
7e675137 NP |
397 | * "Special" mappings do not wish to be associated with a "struct page" (either |
398 | * it doesn't exist, or it exists but they don't want to touch it). In this | |
399 | * case, NULL is returned here. "Normal" mappings do have a struct page. | |
b379d790 | 400 | * |
7e675137 NP |
401 | * There are 2 broad cases. Firstly, an architecture may define a pte_special() |
402 | * pte bit, in which case this function is trivial. Secondly, an architecture | |
403 | * may not have a spare pte bit, which requires a more complicated scheme, | |
404 | * described below. | |
405 | * | |
406 | * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a | |
407 | * special mapping (even if there are underlying and valid "struct pages"). | |
408 | * COWed pages of a VM_PFNMAP are always normal. | |
6aab341e | 409 | * |
b379d790 JH |
410 | * The way we recognize COWed pages within VM_PFNMAP mappings is through the |
411 | * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit | |
7e675137 NP |
412 | * set, and the vm_pgoff will point to the first PFN mapped: thus every special |
413 | * mapping will always honor the rule | |
6aab341e LT |
414 | * |
415 | * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT) | |
416 | * | |
7e675137 NP |
417 | * And for normal mappings this is false. |
418 | * | |
419 | * This restricts such mappings to be a linear translation from virtual address | |
420 | * to pfn. To get around this restriction, we allow arbitrary mappings so long | |
421 | * as the vma is not a COW mapping; in that case, we know that all ptes are | |
422 | * special (because none can have been COWed). | |
b379d790 | 423 | * |
b379d790 | 424 | * |
7e675137 | 425 | * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP. |
b379d790 JH |
426 | * |
427 | * VM_MIXEDMAP mappings can likewise contain memory with or without "struct | |
428 | * page" backing, however the difference is that _all_ pages with a struct | |
429 | * page (that is, those where pfn_valid is true) are refcounted and considered | |
430 | * normal pages by the VM. The disadvantage is that pages are refcounted | |
431 | * (which can be slower and simply not an option for some PFNMAP users). The | |
432 | * advantage is that we don't have to follow the strict linearity rule of | |
433 | * PFNMAP mappings in order to support COWable mappings. | |
434 | * | |
ee498ed7 | 435 | */ |
7e675137 NP |
436 | #ifdef __HAVE_ARCH_PTE_SPECIAL |
437 | # define HAVE_PTE_SPECIAL 1 | |
438 | #else | |
439 | # define HAVE_PTE_SPECIAL 0 | |
440 | #endif | |
441 | struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, | |
442 | pte_t pte) | |
ee498ed7 | 443 | { |
7e675137 NP |
444 | unsigned long pfn; |
445 | ||
446 | if (HAVE_PTE_SPECIAL) { | |
447 | if (likely(!pte_special(pte))) { | |
448 | VM_BUG_ON(!pfn_valid(pte_pfn(pte))); | |
449 | return pte_page(pte); | |
450 | } | |
451 | VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))); | |
452 | return NULL; | |
453 | } | |
454 | ||
455 | /* !HAVE_PTE_SPECIAL case follows: */ | |
456 | ||
457 | pfn = pte_pfn(pte); | |
6aab341e | 458 | |
b379d790 JH |
459 | if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) { |
460 | if (vma->vm_flags & VM_MIXEDMAP) { | |
461 | if (!pfn_valid(pfn)) | |
462 | return NULL; | |
463 | goto out; | |
464 | } else { | |
7e675137 NP |
465 | unsigned long off; |
466 | off = (addr - vma->vm_start) >> PAGE_SHIFT; | |
b379d790 JH |
467 | if (pfn == vma->vm_pgoff + off) |
468 | return NULL; | |
469 | if (!is_cow_mapping(vma->vm_flags)) | |
470 | return NULL; | |
471 | } | |
6aab341e LT |
472 | } |
473 | ||
7e675137 | 474 | VM_BUG_ON(!pfn_valid(pfn)); |
6aab341e LT |
475 | |
476 | /* | |
7e675137 | 477 | * NOTE! We still have PageReserved() pages in the page tables. |
6aab341e | 478 | * |
7e675137 | 479 | * eg. VDSO mappings can cause them to exist. |
6aab341e | 480 | */ |
b379d790 | 481 | out: |
6aab341e | 482 | return pfn_to_page(pfn); |
ee498ed7 HD |
483 | } |
484 | ||
1da177e4 LT |
485 | /* |
486 | * copy one vm_area from one task to the other. Assumes the page tables | |
487 | * already present in the new task to be cleared in the whole range | |
488 | * covered by this vma. | |
1da177e4 LT |
489 | */ |
490 | ||
8c103762 | 491 | static inline void |
1da177e4 | 492 | copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, |
b5810039 | 493 | pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma, |
8c103762 | 494 | unsigned long addr, int *rss) |
1da177e4 | 495 | { |
b5810039 | 496 | unsigned long vm_flags = vma->vm_flags; |
1da177e4 LT |
497 | pte_t pte = *src_pte; |
498 | struct page *page; | |
1da177e4 LT |
499 | |
500 | /* pte contains position in swap or file, so copy. */ | |
501 | if (unlikely(!pte_present(pte))) { | |
502 | if (!pte_file(pte)) { | |
0697212a CL |
503 | swp_entry_t entry = pte_to_swp_entry(pte); |
504 | ||
505 | swap_duplicate(entry); | |
1da177e4 LT |
506 | /* make sure dst_mm is on swapoff's mmlist. */ |
507 | if (unlikely(list_empty(&dst_mm->mmlist))) { | |
508 | spin_lock(&mmlist_lock); | |
f412ac08 HD |
509 | if (list_empty(&dst_mm->mmlist)) |
510 | list_add(&dst_mm->mmlist, | |
511 | &src_mm->mmlist); | |
1da177e4 LT |
512 | spin_unlock(&mmlist_lock); |
513 | } | |
0697212a CL |
514 | if (is_write_migration_entry(entry) && |
515 | is_cow_mapping(vm_flags)) { | |
516 | /* | |
517 | * COW mappings require pages in both parent | |
518 | * and child to be set to read. | |
519 | */ | |
520 | make_migration_entry_read(&entry); | |
521 | pte = swp_entry_to_pte(entry); | |
522 | set_pte_at(src_mm, addr, src_pte, pte); | |
523 | } | |
1da177e4 | 524 | } |
ae859762 | 525 | goto out_set_pte; |
1da177e4 LT |
526 | } |
527 | ||
1da177e4 LT |
528 | /* |
529 | * If it's a COW mapping, write protect it both | |
530 | * in the parent and the child | |
531 | */ | |
67121172 | 532 | if (is_cow_mapping(vm_flags)) { |
1da177e4 | 533 | ptep_set_wrprotect(src_mm, addr, src_pte); |
3dc90795 | 534 | pte = pte_wrprotect(pte); |
1da177e4 LT |
535 | } |
536 | ||
537 | /* | |
538 | * If it's a shared mapping, mark it clean in | |
539 | * the child | |
540 | */ | |
541 | if (vm_flags & VM_SHARED) | |
542 | pte = pte_mkclean(pte); | |
543 | pte = pte_mkold(pte); | |
6aab341e LT |
544 | |
545 | page = vm_normal_page(vma, addr, pte); | |
546 | if (page) { | |
547 | get_page(page); | |
c97a9e10 | 548 | page_dup_rmap(page, vma, addr); |
6aab341e LT |
549 | rss[!!PageAnon(page)]++; |
550 | } | |
ae859762 HD |
551 | |
552 | out_set_pte: | |
553 | set_pte_at(dst_mm, addr, dst_pte, pte); | |
1da177e4 LT |
554 | } |
555 | ||
556 | static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
557 | pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma, | |
558 | unsigned long addr, unsigned long end) | |
559 | { | |
560 | pte_t *src_pte, *dst_pte; | |
c74df32c | 561 | spinlock_t *src_ptl, *dst_ptl; |
e040f218 | 562 | int progress = 0; |
8c103762 | 563 | int rss[2]; |
1da177e4 LT |
564 | |
565 | again: | |
ae859762 | 566 | rss[1] = rss[0] = 0; |
c74df32c | 567 | dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl); |
1da177e4 LT |
568 | if (!dst_pte) |
569 | return -ENOMEM; | |
570 | src_pte = pte_offset_map_nested(src_pmd, addr); | |
4c21e2f2 | 571 | src_ptl = pte_lockptr(src_mm, src_pmd); |
f20dc5f7 | 572 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
6606c3e0 | 573 | arch_enter_lazy_mmu_mode(); |
1da177e4 | 574 | |
1da177e4 LT |
575 | do { |
576 | /* | |
577 | * We are holding two locks at this point - either of them | |
578 | * could generate latencies in another task on another CPU. | |
579 | */ | |
e040f218 HD |
580 | if (progress >= 32) { |
581 | progress = 0; | |
582 | if (need_resched() || | |
95c354fe | 583 | spin_needbreak(src_ptl) || spin_needbreak(dst_ptl)) |
e040f218 HD |
584 | break; |
585 | } | |
1da177e4 LT |
586 | if (pte_none(*src_pte)) { |
587 | progress++; | |
588 | continue; | |
589 | } | |
8c103762 | 590 | copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss); |
1da177e4 LT |
591 | progress += 8; |
592 | } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end); | |
1da177e4 | 593 | |
6606c3e0 | 594 | arch_leave_lazy_mmu_mode(); |
c74df32c | 595 | spin_unlock(src_ptl); |
1da177e4 | 596 | pte_unmap_nested(src_pte - 1); |
ae859762 | 597 | add_mm_rss(dst_mm, rss[0], rss[1]); |
c74df32c HD |
598 | pte_unmap_unlock(dst_pte - 1, dst_ptl); |
599 | cond_resched(); | |
1da177e4 LT |
600 | if (addr != end) |
601 | goto again; | |
602 | return 0; | |
603 | } | |
604 | ||
605 | static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
606 | pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma, | |
607 | unsigned long addr, unsigned long end) | |
608 | { | |
609 | pmd_t *src_pmd, *dst_pmd; | |
610 | unsigned long next; | |
611 | ||
612 | dst_pmd = pmd_alloc(dst_mm, dst_pud, addr); | |
613 | if (!dst_pmd) | |
614 | return -ENOMEM; | |
615 | src_pmd = pmd_offset(src_pud, addr); | |
616 | do { | |
617 | next = pmd_addr_end(addr, end); | |
618 | if (pmd_none_or_clear_bad(src_pmd)) | |
619 | continue; | |
620 | if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd, | |
621 | vma, addr, next)) | |
622 | return -ENOMEM; | |
623 | } while (dst_pmd++, src_pmd++, addr = next, addr != end); | |
624 | return 0; | |
625 | } | |
626 | ||
627 | static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
628 | pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma, | |
629 | unsigned long addr, unsigned long end) | |
630 | { | |
631 | pud_t *src_pud, *dst_pud; | |
632 | unsigned long next; | |
633 | ||
634 | dst_pud = pud_alloc(dst_mm, dst_pgd, addr); | |
635 | if (!dst_pud) | |
636 | return -ENOMEM; | |
637 | src_pud = pud_offset(src_pgd, addr); | |
638 | do { | |
639 | next = pud_addr_end(addr, end); | |
640 | if (pud_none_or_clear_bad(src_pud)) | |
641 | continue; | |
642 | if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud, | |
643 | vma, addr, next)) | |
644 | return -ENOMEM; | |
645 | } while (dst_pud++, src_pud++, addr = next, addr != end); | |
646 | return 0; | |
647 | } | |
648 | ||
649 | int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, | |
650 | struct vm_area_struct *vma) | |
651 | { | |
652 | pgd_t *src_pgd, *dst_pgd; | |
653 | unsigned long next; | |
654 | unsigned long addr = vma->vm_start; | |
655 | unsigned long end = vma->vm_end; | |
cddb8a5c | 656 | int ret; |
1da177e4 | 657 | |
d992895b NP |
658 | /* |
659 | * Don't copy ptes where a page fault will fill them correctly. | |
660 | * Fork becomes much lighter when there are big shared or private | |
661 | * readonly mappings. The tradeoff is that copy_page_range is more | |
662 | * efficient than faulting. | |
663 | */ | |
4d7672b4 | 664 | if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) { |
d992895b NP |
665 | if (!vma->anon_vma) |
666 | return 0; | |
667 | } | |
668 | ||
1da177e4 LT |
669 | if (is_vm_hugetlb_page(vma)) |
670 | return copy_hugetlb_page_range(dst_mm, src_mm, vma); | |
671 | ||
cddb8a5c AA |
672 | /* |
673 | * We need to invalidate the secondary MMU mappings only when | |
674 | * there could be a permission downgrade on the ptes of the | |
675 | * parent mm. And a permission downgrade will only happen if | |
676 | * is_cow_mapping() returns true. | |
677 | */ | |
678 | if (is_cow_mapping(vma->vm_flags)) | |
679 | mmu_notifier_invalidate_range_start(src_mm, addr, end); | |
680 | ||
681 | ret = 0; | |
1da177e4 LT |
682 | dst_pgd = pgd_offset(dst_mm, addr); |
683 | src_pgd = pgd_offset(src_mm, addr); | |
684 | do { | |
685 | next = pgd_addr_end(addr, end); | |
686 | if (pgd_none_or_clear_bad(src_pgd)) | |
687 | continue; | |
cddb8a5c AA |
688 | if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd, |
689 | vma, addr, next))) { | |
690 | ret = -ENOMEM; | |
691 | break; | |
692 | } | |
1da177e4 | 693 | } while (dst_pgd++, src_pgd++, addr = next, addr != end); |
cddb8a5c AA |
694 | |
695 | if (is_cow_mapping(vma->vm_flags)) | |
696 | mmu_notifier_invalidate_range_end(src_mm, | |
697 | vma->vm_start, end); | |
698 | return ret; | |
1da177e4 LT |
699 | } |
700 | ||
51c6f666 | 701 | static unsigned long zap_pte_range(struct mmu_gather *tlb, |
b5810039 | 702 | struct vm_area_struct *vma, pmd_t *pmd, |
1da177e4 | 703 | unsigned long addr, unsigned long end, |
51c6f666 | 704 | long *zap_work, struct zap_details *details) |
1da177e4 | 705 | { |
b5810039 | 706 | struct mm_struct *mm = tlb->mm; |
1da177e4 | 707 | pte_t *pte; |
508034a3 | 708 | spinlock_t *ptl; |
ae859762 HD |
709 | int file_rss = 0; |
710 | int anon_rss = 0; | |
1da177e4 | 711 | |
508034a3 | 712 | pte = pte_offset_map_lock(mm, pmd, addr, &ptl); |
6606c3e0 | 713 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
714 | do { |
715 | pte_t ptent = *pte; | |
51c6f666 RH |
716 | if (pte_none(ptent)) { |
717 | (*zap_work)--; | |
1da177e4 | 718 | continue; |
51c6f666 | 719 | } |
6f5e6b9e HD |
720 | |
721 | (*zap_work) -= PAGE_SIZE; | |
722 | ||
1da177e4 | 723 | if (pte_present(ptent)) { |
ee498ed7 | 724 | struct page *page; |
51c6f666 | 725 | |
6aab341e | 726 | page = vm_normal_page(vma, addr, ptent); |
1da177e4 LT |
727 | if (unlikely(details) && page) { |
728 | /* | |
729 | * unmap_shared_mapping_pages() wants to | |
730 | * invalidate cache without truncating: | |
731 | * unmap shared but keep private pages. | |
732 | */ | |
733 | if (details->check_mapping && | |
734 | details->check_mapping != page->mapping) | |
735 | continue; | |
736 | /* | |
737 | * Each page->index must be checked when | |
738 | * invalidating or truncating nonlinear. | |
739 | */ | |
740 | if (details->nonlinear_vma && | |
741 | (page->index < details->first_index || | |
742 | page->index > details->last_index)) | |
743 | continue; | |
744 | } | |
b5810039 | 745 | ptent = ptep_get_and_clear_full(mm, addr, pte, |
a600388d | 746 | tlb->fullmm); |
1da177e4 LT |
747 | tlb_remove_tlb_entry(tlb, pte, addr); |
748 | if (unlikely(!page)) | |
749 | continue; | |
750 | if (unlikely(details) && details->nonlinear_vma | |
751 | && linear_page_index(details->nonlinear_vma, | |
752 | addr) != page->index) | |
b5810039 | 753 | set_pte_at(mm, addr, pte, |
1da177e4 | 754 | pgoff_to_pte(page->index)); |
1da177e4 | 755 | if (PageAnon(page)) |
86d912f4 | 756 | anon_rss--; |
6237bcd9 HD |
757 | else { |
758 | if (pte_dirty(ptent)) | |
759 | set_page_dirty(page); | |
760 | if (pte_young(ptent)) | |
daa88c8d | 761 | SetPageReferenced(page); |
86d912f4 | 762 | file_rss--; |
6237bcd9 | 763 | } |
7de6b805 | 764 | page_remove_rmap(page, vma); |
1da177e4 LT |
765 | tlb_remove_page(tlb, page); |
766 | continue; | |
767 | } | |
768 | /* | |
769 | * If details->check_mapping, we leave swap entries; | |
770 | * if details->nonlinear_vma, we leave file entries. | |
771 | */ | |
772 | if (unlikely(details)) | |
773 | continue; | |
774 | if (!pte_file(ptent)) | |
775 | free_swap_and_cache(pte_to_swp_entry(ptent)); | |
9888a1ca | 776 | pte_clear_not_present_full(mm, addr, pte, tlb->fullmm); |
51c6f666 | 777 | } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0)); |
ae859762 | 778 | |
86d912f4 | 779 | add_mm_rss(mm, file_rss, anon_rss); |
6606c3e0 | 780 | arch_leave_lazy_mmu_mode(); |
508034a3 | 781 | pte_unmap_unlock(pte - 1, ptl); |
51c6f666 RH |
782 | |
783 | return addr; | |
1da177e4 LT |
784 | } |
785 | ||
51c6f666 | 786 | static inline unsigned long zap_pmd_range(struct mmu_gather *tlb, |
b5810039 | 787 | struct vm_area_struct *vma, pud_t *pud, |
1da177e4 | 788 | unsigned long addr, unsigned long end, |
51c6f666 | 789 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
790 | { |
791 | pmd_t *pmd; | |
792 | unsigned long next; | |
793 | ||
794 | pmd = pmd_offset(pud, addr); | |
795 | do { | |
796 | next = pmd_addr_end(addr, end); | |
51c6f666 RH |
797 | if (pmd_none_or_clear_bad(pmd)) { |
798 | (*zap_work)--; | |
1da177e4 | 799 | continue; |
51c6f666 RH |
800 | } |
801 | next = zap_pte_range(tlb, vma, pmd, addr, next, | |
802 | zap_work, details); | |
803 | } while (pmd++, addr = next, (addr != end && *zap_work > 0)); | |
804 | ||
805 | return addr; | |
1da177e4 LT |
806 | } |
807 | ||
51c6f666 | 808 | static inline unsigned long zap_pud_range(struct mmu_gather *tlb, |
b5810039 | 809 | struct vm_area_struct *vma, pgd_t *pgd, |
1da177e4 | 810 | unsigned long addr, unsigned long end, |
51c6f666 | 811 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
812 | { |
813 | pud_t *pud; | |
814 | unsigned long next; | |
815 | ||
816 | pud = pud_offset(pgd, addr); | |
817 | do { | |
818 | next = pud_addr_end(addr, end); | |
51c6f666 RH |
819 | if (pud_none_or_clear_bad(pud)) { |
820 | (*zap_work)--; | |
1da177e4 | 821 | continue; |
51c6f666 RH |
822 | } |
823 | next = zap_pmd_range(tlb, vma, pud, addr, next, | |
824 | zap_work, details); | |
825 | } while (pud++, addr = next, (addr != end && *zap_work > 0)); | |
826 | ||
827 | return addr; | |
1da177e4 LT |
828 | } |
829 | ||
51c6f666 RH |
830 | static unsigned long unmap_page_range(struct mmu_gather *tlb, |
831 | struct vm_area_struct *vma, | |
1da177e4 | 832 | unsigned long addr, unsigned long end, |
51c6f666 | 833 | long *zap_work, struct zap_details *details) |
1da177e4 LT |
834 | { |
835 | pgd_t *pgd; | |
836 | unsigned long next; | |
837 | ||
838 | if (details && !details->check_mapping && !details->nonlinear_vma) | |
839 | details = NULL; | |
840 | ||
841 | BUG_ON(addr >= end); | |
842 | tlb_start_vma(tlb, vma); | |
843 | pgd = pgd_offset(vma->vm_mm, addr); | |
844 | do { | |
845 | next = pgd_addr_end(addr, end); | |
51c6f666 RH |
846 | if (pgd_none_or_clear_bad(pgd)) { |
847 | (*zap_work)--; | |
1da177e4 | 848 | continue; |
51c6f666 RH |
849 | } |
850 | next = zap_pud_range(tlb, vma, pgd, addr, next, | |
851 | zap_work, details); | |
852 | } while (pgd++, addr = next, (addr != end && *zap_work > 0)); | |
1da177e4 | 853 | tlb_end_vma(tlb, vma); |
51c6f666 RH |
854 | |
855 | return addr; | |
1da177e4 LT |
856 | } |
857 | ||
858 | #ifdef CONFIG_PREEMPT | |
859 | # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE) | |
860 | #else | |
861 | /* No preempt: go for improved straight-line efficiency */ | |
862 | # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE) | |
863 | #endif | |
864 | ||
865 | /** | |
866 | * unmap_vmas - unmap a range of memory covered by a list of vma's | |
867 | * @tlbp: address of the caller's struct mmu_gather | |
1da177e4 LT |
868 | * @vma: the starting vma |
869 | * @start_addr: virtual address at which to start unmapping | |
870 | * @end_addr: virtual address at which to end unmapping | |
871 | * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here | |
872 | * @details: details of nonlinear truncation or shared cache invalidation | |
873 | * | |
ee39b37b | 874 | * Returns the end address of the unmapping (restart addr if interrupted). |
1da177e4 | 875 | * |
508034a3 | 876 | * Unmap all pages in the vma list. |
1da177e4 | 877 | * |
508034a3 HD |
878 | * We aim to not hold locks for too long (for scheduling latency reasons). |
879 | * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to | |
1da177e4 LT |
880 | * return the ending mmu_gather to the caller. |
881 | * | |
882 | * Only addresses between `start' and `end' will be unmapped. | |
883 | * | |
884 | * The VMA list must be sorted in ascending virtual address order. | |
885 | * | |
886 | * unmap_vmas() assumes that the caller will flush the whole unmapped address | |
887 | * range after unmap_vmas() returns. So the only responsibility here is to | |
888 | * ensure that any thus-far unmapped pages are flushed before unmap_vmas() | |
889 | * drops the lock and schedules. | |
890 | */ | |
508034a3 | 891 | unsigned long unmap_vmas(struct mmu_gather **tlbp, |
1da177e4 LT |
892 | struct vm_area_struct *vma, unsigned long start_addr, |
893 | unsigned long end_addr, unsigned long *nr_accounted, | |
894 | struct zap_details *details) | |
895 | { | |
51c6f666 | 896 | long zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
897 | unsigned long tlb_start = 0; /* For tlb_finish_mmu */ |
898 | int tlb_start_valid = 0; | |
ee39b37b | 899 | unsigned long start = start_addr; |
1da177e4 | 900 | spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL; |
4d6ddfa9 | 901 | int fullmm = (*tlbp)->fullmm; |
cddb8a5c | 902 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 903 | |
cddb8a5c | 904 | mmu_notifier_invalidate_range_start(mm, start_addr, end_addr); |
1da177e4 | 905 | for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) { |
1da177e4 LT |
906 | unsigned long end; |
907 | ||
908 | start = max(vma->vm_start, start_addr); | |
909 | if (start >= vma->vm_end) | |
910 | continue; | |
911 | end = min(vma->vm_end, end_addr); | |
912 | if (end <= vma->vm_start) | |
913 | continue; | |
914 | ||
915 | if (vma->vm_flags & VM_ACCOUNT) | |
916 | *nr_accounted += (end - start) >> PAGE_SHIFT; | |
917 | ||
1da177e4 | 918 | while (start != end) { |
1da177e4 LT |
919 | if (!tlb_start_valid) { |
920 | tlb_start = start; | |
921 | tlb_start_valid = 1; | |
922 | } | |
923 | ||
51c6f666 | 924 | if (unlikely(is_vm_hugetlb_page(vma))) { |
a137e1cc AK |
925 | /* |
926 | * It is undesirable to test vma->vm_file as it | |
927 | * should be non-null for valid hugetlb area. | |
928 | * However, vm_file will be NULL in the error | |
929 | * cleanup path of do_mmap_pgoff. When | |
930 | * hugetlbfs ->mmap method fails, | |
931 | * do_mmap_pgoff() nullifies vma->vm_file | |
932 | * before calling this function to clean up. | |
933 | * Since no pte has actually been setup, it is | |
934 | * safe to do nothing in this case. | |
935 | */ | |
936 | if (vma->vm_file) { | |
937 | unmap_hugepage_range(vma, start, end, NULL); | |
938 | zap_work -= (end - start) / | |
a5516438 | 939 | pages_per_huge_page(hstate_vma(vma)); |
a137e1cc AK |
940 | } |
941 | ||
51c6f666 RH |
942 | start = end; |
943 | } else | |
944 | start = unmap_page_range(*tlbp, vma, | |
945 | start, end, &zap_work, details); | |
946 | ||
947 | if (zap_work > 0) { | |
948 | BUG_ON(start != end); | |
949 | break; | |
1da177e4 LT |
950 | } |
951 | ||
1da177e4 LT |
952 | tlb_finish_mmu(*tlbp, tlb_start, start); |
953 | ||
954 | if (need_resched() || | |
95c354fe | 955 | (i_mmap_lock && spin_needbreak(i_mmap_lock))) { |
1da177e4 | 956 | if (i_mmap_lock) { |
508034a3 | 957 | *tlbp = NULL; |
1da177e4 LT |
958 | goto out; |
959 | } | |
1da177e4 | 960 | cond_resched(); |
1da177e4 LT |
961 | } |
962 | ||
508034a3 | 963 | *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm); |
1da177e4 | 964 | tlb_start_valid = 0; |
51c6f666 | 965 | zap_work = ZAP_BLOCK_SIZE; |
1da177e4 LT |
966 | } |
967 | } | |
968 | out: | |
cddb8a5c | 969 | mmu_notifier_invalidate_range_end(mm, start_addr, end_addr); |
ee39b37b | 970 | return start; /* which is now the end (or restart) address */ |
1da177e4 LT |
971 | } |
972 | ||
973 | /** | |
974 | * zap_page_range - remove user pages in a given range | |
975 | * @vma: vm_area_struct holding the applicable pages | |
976 | * @address: starting address of pages to zap | |
977 | * @size: number of bytes to zap | |
978 | * @details: details of nonlinear truncation or shared cache invalidation | |
979 | */ | |
ee39b37b | 980 | unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, |
1da177e4 LT |
981 | unsigned long size, struct zap_details *details) |
982 | { | |
983 | struct mm_struct *mm = vma->vm_mm; | |
984 | struct mmu_gather *tlb; | |
985 | unsigned long end = address + size; | |
986 | unsigned long nr_accounted = 0; | |
987 | ||
1da177e4 | 988 | lru_add_drain(); |
1da177e4 | 989 | tlb = tlb_gather_mmu(mm, 0); |
365e9c87 | 990 | update_hiwater_rss(mm); |
508034a3 HD |
991 | end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details); |
992 | if (tlb) | |
993 | tlb_finish_mmu(tlb, address, end); | |
ee39b37b | 994 | return end; |
1da177e4 LT |
995 | } |
996 | ||
c627f9cc JS |
997 | /** |
998 | * zap_vma_ptes - remove ptes mapping the vma | |
999 | * @vma: vm_area_struct holding ptes to be zapped | |
1000 | * @address: starting address of pages to zap | |
1001 | * @size: number of bytes to zap | |
1002 | * | |
1003 | * This function only unmaps ptes assigned to VM_PFNMAP vmas. | |
1004 | * | |
1005 | * The entire address range must be fully contained within the vma. | |
1006 | * | |
1007 | * Returns 0 if successful. | |
1008 | */ | |
1009 | int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address, | |
1010 | unsigned long size) | |
1011 | { | |
1012 | if (address < vma->vm_start || address + size > vma->vm_end || | |
1013 | !(vma->vm_flags & VM_PFNMAP)) | |
1014 | return -1; | |
1015 | zap_page_range(vma, address, size, NULL); | |
1016 | return 0; | |
1017 | } | |
1018 | EXPORT_SYMBOL_GPL(zap_vma_ptes); | |
1019 | ||
1da177e4 LT |
1020 | /* |
1021 | * Do a quick page-table lookup for a single page. | |
1da177e4 | 1022 | */ |
6aab341e | 1023 | struct page *follow_page(struct vm_area_struct *vma, unsigned long address, |
deceb6cd | 1024 | unsigned int flags) |
1da177e4 LT |
1025 | { |
1026 | pgd_t *pgd; | |
1027 | pud_t *pud; | |
1028 | pmd_t *pmd; | |
1029 | pte_t *ptep, pte; | |
deceb6cd | 1030 | spinlock_t *ptl; |
1da177e4 | 1031 | struct page *page; |
6aab341e | 1032 | struct mm_struct *mm = vma->vm_mm; |
1da177e4 | 1033 | |
deceb6cd HD |
1034 | page = follow_huge_addr(mm, address, flags & FOLL_WRITE); |
1035 | if (!IS_ERR(page)) { | |
1036 | BUG_ON(flags & FOLL_GET); | |
1037 | goto out; | |
1038 | } | |
1da177e4 | 1039 | |
deceb6cd | 1040 | page = NULL; |
1da177e4 LT |
1041 | pgd = pgd_offset(mm, address); |
1042 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
deceb6cd | 1043 | goto no_page_table; |
1da177e4 LT |
1044 | |
1045 | pud = pud_offset(pgd, address); | |
ceb86879 | 1046 | if (pud_none(*pud)) |
deceb6cd | 1047 | goto no_page_table; |
ceb86879 AK |
1048 | if (pud_huge(*pud)) { |
1049 | BUG_ON(flags & FOLL_GET); | |
1050 | page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE); | |
1051 | goto out; | |
1052 | } | |
1053 | if (unlikely(pud_bad(*pud))) | |
1054 | goto no_page_table; | |
1055 | ||
1da177e4 | 1056 | pmd = pmd_offset(pud, address); |
aeed5fce | 1057 | if (pmd_none(*pmd)) |
deceb6cd | 1058 | goto no_page_table; |
deceb6cd HD |
1059 | if (pmd_huge(*pmd)) { |
1060 | BUG_ON(flags & FOLL_GET); | |
1061 | page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE); | |
1da177e4 | 1062 | goto out; |
deceb6cd | 1063 | } |
aeed5fce HD |
1064 | if (unlikely(pmd_bad(*pmd))) |
1065 | goto no_page_table; | |
1066 | ||
deceb6cd | 1067 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
1068 | |
1069 | pte = *ptep; | |
deceb6cd | 1070 | if (!pte_present(pte)) |
89f5b7da | 1071 | goto no_page; |
deceb6cd HD |
1072 | if ((flags & FOLL_WRITE) && !pte_write(pte)) |
1073 | goto unlock; | |
6aab341e LT |
1074 | page = vm_normal_page(vma, address, pte); |
1075 | if (unlikely(!page)) | |
89f5b7da | 1076 | goto bad_page; |
1da177e4 | 1077 | |
deceb6cd HD |
1078 | if (flags & FOLL_GET) |
1079 | get_page(page); | |
1080 | if (flags & FOLL_TOUCH) { | |
1081 | if ((flags & FOLL_WRITE) && | |
1082 | !pte_dirty(pte) && !PageDirty(page)) | |
1083 | set_page_dirty(page); | |
1084 | mark_page_accessed(page); | |
1085 | } | |
1086 | unlock: | |
1087 | pte_unmap_unlock(ptep, ptl); | |
1da177e4 | 1088 | out: |
deceb6cd | 1089 | return page; |
1da177e4 | 1090 | |
89f5b7da LT |
1091 | bad_page: |
1092 | pte_unmap_unlock(ptep, ptl); | |
1093 | return ERR_PTR(-EFAULT); | |
1094 | ||
1095 | no_page: | |
1096 | pte_unmap_unlock(ptep, ptl); | |
1097 | if (!pte_none(pte)) | |
1098 | return page; | |
1099 | /* Fall through to ZERO_PAGE handling */ | |
deceb6cd HD |
1100 | no_page_table: |
1101 | /* | |
1102 | * When core dumping an enormous anonymous area that nobody | |
1103 | * has touched so far, we don't want to allocate page tables. | |
1104 | */ | |
1105 | if (flags & FOLL_ANON) { | |
557ed1fa | 1106 | page = ZERO_PAGE(0); |
deceb6cd HD |
1107 | if (flags & FOLL_GET) |
1108 | get_page(page); | |
1109 | BUG_ON(flags & FOLL_WRITE); | |
1110 | } | |
1111 | return page; | |
1da177e4 LT |
1112 | } |
1113 | ||
672ca28e LT |
1114 | /* Can we do the FOLL_ANON optimization? */ |
1115 | static inline int use_zero_page(struct vm_area_struct *vma) | |
1116 | { | |
1117 | /* | |
1118 | * We don't want to optimize FOLL_ANON for make_pages_present() | |
1119 | * when it tries to page in a VM_LOCKED region. As to VM_SHARED, | |
1120 | * we want to get the page from the page tables to make sure | |
1121 | * that we serialize and update with any other user of that | |
1122 | * mapping. | |
1123 | */ | |
1124 | if (vma->vm_flags & (VM_LOCKED | VM_SHARED)) | |
1125 | return 0; | |
1126 | /* | |
0d71d10a | 1127 | * And if we have a fault routine, it's not an anonymous region. |
672ca28e | 1128 | */ |
0d71d10a | 1129 | return !vma->vm_ops || !vma->vm_ops->fault; |
672ca28e LT |
1130 | } |
1131 | ||
b291f000 NP |
1132 | |
1133 | ||
1134 | int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | |
1135 | unsigned long start, int len, int flags, | |
1da177e4 LT |
1136 | struct page **pages, struct vm_area_struct **vmas) |
1137 | { | |
1138 | int i; | |
b291f000 NP |
1139 | unsigned int vm_flags = 0; |
1140 | int write = !!(flags & GUP_FLAGS_WRITE); | |
1141 | int force = !!(flags & GUP_FLAGS_FORCE); | |
1142 | int ignore = !!(flags & GUP_FLAGS_IGNORE_VMA_PERMISSIONS); | |
1da177e4 | 1143 | |
900cf086 JC |
1144 | if (len <= 0) |
1145 | return 0; | |
1da177e4 LT |
1146 | /* |
1147 | * Require read or write permissions. | |
1148 | * If 'force' is set, we only require the "MAY" flags. | |
1149 | */ | |
deceb6cd HD |
1150 | vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD); |
1151 | vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE); | |
1da177e4 LT |
1152 | i = 0; |
1153 | ||
1154 | do { | |
deceb6cd HD |
1155 | struct vm_area_struct *vma; |
1156 | unsigned int foll_flags; | |
1da177e4 LT |
1157 | |
1158 | vma = find_extend_vma(mm, start); | |
1159 | if (!vma && in_gate_area(tsk, start)) { | |
1160 | unsigned long pg = start & PAGE_MASK; | |
1161 | struct vm_area_struct *gate_vma = get_gate_vma(tsk); | |
1162 | pgd_t *pgd; | |
1163 | pud_t *pud; | |
1164 | pmd_t *pmd; | |
1165 | pte_t *pte; | |
b291f000 NP |
1166 | |
1167 | /* user gate pages are read-only */ | |
1168 | if (!ignore && write) | |
1da177e4 LT |
1169 | return i ? : -EFAULT; |
1170 | if (pg > TASK_SIZE) | |
1171 | pgd = pgd_offset_k(pg); | |
1172 | else | |
1173 | pgd = pgd_offset_gate(mm, pg); | |
1174 | BUG_ON(pgd_none(*pgd)); | |
1175 | pud = pud_offset(pgd, pg); | |
1176 | BUG_ON(pud_none(*pud)); | |
1177 | pmd = pmd_offset(pud, pg); | |
690dbe1c HD |
1178 | if (pmd_none(*pmd)) |
1179 | return i ? : -EFAULT; | |
1da177e4 | 1180 | pte = pte_offset_map(pmd, pg); |
690dbe1c HD |
1181 | if (pte_none(*pte)) { |
1182 | pte_unmap(pte); | |
1183 | return i ? : -EFAULT; | |
1184 | } | |
1da177e4 | 1185 | if (pages) { |
fa2a455b | 1186 | struct page *page = vm_normal_page(gate_vma, start, *pte); |
6aab341e LT |
1187 | pages[i] = page; |
1188 | if (page) | |
1189 | get_page(page); | |
1da177e4 LT |
1190 | } |
1191 | pte_unmap(pte); | |
1192 | if (vmas) | |
1193 | vmas[i] = gate_vma; | |
1194 | i++; | |
1195 | start += PAGE_SIZE; | |
1196 | len--; | |
1197 | continue; | |
1198 | } | |
1199 | ||
b291f000 NP |
1200 | if (!vma || |
1201 | (vma->vm_flags & (VM_IO | VM_PFNMAP)) || | |
1202 | (!ignore && !(vm_flags & vma->vm_flags))) | |
1da177e4 LT |
1203 | return i ? : -EFAULT; |
1204 | ||
1205 | if (is_vm_hugetlb_page(vma)) { | |
1206 | i = follow_hugetlb_page(mm, vma, pages, vmas, | |
5b23dbe8 | 1207 | &start, &len, i, write); |
1da177e4 LT |
1208 | continue; |
1209 | } | |
deceb6cd HD |
1210 | |
1211 | foll_flags = FOLL_TOUCH; | |
1212 | if (pages) | |
1213 | foll_flags |= FOLL_GET; | |
672ca28e | 1214 | if (!write && use_zero_page(vma)) |
deceb6cd HD |
1215 | foll_flags |= FOLL_ANON; |
1216 | ||
1da177e4 | 1217 | do { |
08ef4729 | 1218 | struct page *page; |
1da177e4 | 1219 | |
462e00cc ES |
1220 | /* |
1221 | * If tsk is ooming, cut off its access to large memory | |
1222 | * allocations. It has a pending SIGKILL, but it can't | |
1223 | * be processed until returning to user space. | |
1224 | */ | |
1225 | if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE))) | |
7a36a752 | 1226 | return i ? i : -ENOMEM; |
462e00cc | 1227 | |
deceb6cd HD |
1228 | if (write) |
1229 | foll_flags |= FOLL_WRITE; | |
a68d2ebc | 1230 | |
deceb6cd | 1231 | cond_resched(); |
6aab341e | 1232 | while (!(page = follow_page(vma, start, foll_flags))) { |
deceb6cd | 1233 | int ret; |
83c54070 | 1234 | ret = handle_mm_fault(mm, vma, start, |
deceb6cd | 1235 | foll_flags & FOLL_WRITE); |
83c54070 NP |
1236 | if (ret & VM_FAULT_ERROR) { |
1237 | if (ret & VM_FAULT_OOM) | |
1238 | return i ? i : -ENOMEM; | |
1239 | else if (ret & VM_FAULT_SIGBUS) | |
1240 | return i ? i : -EFAULT; | |
1241 | BUG(); | |
1242 | } | |
1243 | if (ret & VM_FAULT_MAJOR) | |
1244 | tsk->maj_flt++; | |
1245 | else | |
1246 | tsk->min_flt++; | |
1247 | ||
a68d2ebc | 1248 | /* |
83c54070 NP |
1249 | * The VM_FAULT_WRITE bit tells us that |
1250 | * do_wp_page has broken COW when necessary, | |
1251 | * even if maybe_mkwrite decided not to set | |
1252 | * pte_write. We can thus safely do subsequent | |
1253 | * page lookups as if they were reads. | |
a68d2ebc LT |
1254 | */ |
1255 | if (ret & VM_FAULT_WRITE) | |
deceb6cd | 1256 | foll_flags &= ~FOLL_WRITE; |
83c54070 | 1257 | |
7f7bbbe5 | 1258 | cond_resched(); |
1da177e4 | 1259 | } |
89f5b7da LT |
1260 | if (IS_ERR(page)) |
1261 | return i ? i : PTR_ERR(page); | |
1da177e4 | 1262 | if (pages) { |
08ef4729 | 1263 | pages[i] = page; |
03beb076 | 1264 | |
a6f36be3 | 1265 | flush_anon_page(vma, page, start); |
08ef4729 | 1266 | flush_dcache_page(page); |
1da177e4 LT |
1267 | } |
1268 | if (vmas) | |
1269 | vmas[i] = vma; | |
1270 | i++; | |
1271 | start += PAGE_SIZE; | |
1272 | len--; | |
08ef4729 | 1273 | } while (len && start < vma->vm_end); |
08ef4729 | 1274 | } while (len); |
1da177e4 LT |
1275 | return i; |
1276 | } | |
b291f000 NP |
1277 | |
1278 | int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, | |
1279 | unsigned long start, int len, int write, int force, | |
1280 | struct page **pages, struct vm_area_struct **vmas) | |
1281 | { | |
1282 | int flags = 0; | |
1283 | ||
1284 | if (write) | |
1285 | flags |= GUP_FLAGS_WRITE; | |
1286 | if (force) | |
1287 | flags |= GUP_FLAGS_FORCE; | |
1288 | ||
1289 | return __get_user_pages(tsk, mm, | |
1290 | start, len, flags, | |
1291 | pages, vmas); | |
1292 | } | |
1293 | ||
1da177e4 LT |
1294 | EXPORT_SYMBOL(get_user_pages); |
1295 | ||
920c7a5d HH |
1296 | pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, |
1297 | spinlock_t **ptl) | |
c9cfcddf LT |
1298 | { |
1299 | pgd_t * pgd = pgd_offset(mm, addr); | |
1300 | pud_t * pud = pud_alloc(mm, pgd, addr); | |
1301 | if (pud) { | |
49c91fb0 | 1302 | pmd_t * pmd = pmd_alloc(mm, pud, addr); |
c9cfcddf LT |
1303 | if (pmd) |
1304 | return pte_alloc_map_lock(mm, pmd, addr, ptl); | |
1305 | } | |
1306 | return NULL; | |
1307 | } | |
1308 | ||
238f58d8 LT |
1309 | /* |
1310 | * This is the old fallback for page remapping. | |
1311 | * | |
1312 | * For historical reasons, it only allows reserved pages. Only | |
1313 | * old drivers should use this, and they needed to mark their | |
1314 | * pages reserved for the old functions anyway. | |
1315 | */ | |
423bad60 NP |
1316 | static int insert_page(struct vm_area_struct *vma, unsigned long addr, |
1317 | struct page *page, pgprot_t prot) | |
238f58d8 | 1318 | { |
423bad60 | 1319 | struct mm_struct *mm = vma->vm_mm; |
238f58d8 | 1320 | int retval; |
c9cfcddf | 1321 | pte_t *pte; |
8a9f3ccd BS |
1322 | spinlock_t *ptl; |
1323 | ||
238f58d8 | 1324 | retval = -EINVAL; |
a145dd41 | 1325 | if (PageAnon(page)) |
5b4e655e | 1326 | goto out; |
238f58d8 LT |
1327 | retval = -ENOMEM; |
1328 | flush_dcache_page(page); | |
c9cfcddf | 1329 | pte = get_locked_pte(mm, addr, &ptl); |
238f58d8 | 1330 | if (!pte) |
5b4e655e | 1331 | goto out; |
238f58d8 LT |
1332 | retval = -EBUSY; |
1333 | if (!pte_none(*pte)) | |
1334 | goto out_unlock; | |
1335 | ||
1336 | /* Ok, finally just insert the thing.. */ | |
1337 | get_page(page); | |
1338 | inc_mm_counter(mm, file_rss); | |
1339 | page_add_file_rmap(page); | |
1340 | set_pte_at(mm, addr, pte, mk_pte(page, prot)); | |
1341 | ||
1342 | retval = 0; | |
8a9f3ccd BS |
1343 | pte_unmap_unlock(pte, ptl); |
1344 | return retval; | |
238f58d8 LT |
1345 | out_unlock: |
1346 | pte_unmap_unlock(pte, ptl); | |
1347 | out: | |
1348 | return retval; | |
1349 | } | |
1350 | ||
bfa5bf6d REB |
1351 | /** |
1352 | * vm_insert_page - insert single page into user vma | |
1353 | * @vma: user vma to map to | |
1354 | * @addr: target user address of this page | |
1355 | * @page: source kernel page | |
1356 | * | |
a145dd41 LT |
1357 | * This allows drivers to insert individual pages they've allocated |
1358 | * into a user vma. | |
1359 | * | |
1360 | * The page has to be a nice clean _individual_ kernel allocation. | |
1361 | * If you allocate a compound page, you need to have marked it as | |
1362 | * such (__GFP_COMP), or manually just split the page up yourself | |
8dfcc9ba | 1363 | * (see split_page()). |
a145dd41 LT |
1364 | * |
1365 | * NOTE! Traditionally this was done with "remap_pfn_range()" which | |
1366 | * took an arbitrary page protection parameter. This doesn't allow | |
1367 | * that. Your vma protection will have to be set up correctly, which | |
1368 | * means that if you want a shared writable mapping, you'd better | |
1369 | * ask for a shared writable mapping! | |
1370 | * | |
1371 | * The page does not need to be reserved. | |
1372 | */ | |
423bad60 NP |
1373 | int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, |
1374 | struct page *page) | |
a145dd41 LT |
1375 | { |
1376 | if (addr < vma->vm_start || addr >= vma->vm_end) | |
1377 | return -EFAULT; | |
1378 | if (!page_count(page)) | |
1379 | return -EINVAL; | |
4d7672b4 | 1380 | vma->vm_flags |= VM_INSERTPAGE; |
423bad60 | 1381 | return insert_page(vma, addr, page, vma->vm_page_prot); |
a145dd41 | 1382 | } |
e3c3374f | 1383 | EXPORT_SYMBOL(vm_insert_page); |
a145dd41 | 1384 | |
423bad60 NP |
1385 | static int insert_pfn(struct vm_area_struct *vma, unsigned long addr, |
1386 | unsigned long pfn, pgprot_t prot) | |
1387 | { | |
1388 | struct mm_struct *mm = vma->vm_mm; | |
1389 | int retval; | |
1390 | pte_t *pte, entry; | |
1391 | spinlock_t *ptl; | |
1392 | ||
1393 | retval = -ENOMEM; | |
1394 | pte = get_locked_pte(mm, addr, &ptl); | |
1395 | if (!pte) | |
1396 | goto out; | |
1397 | retval = -EBUSY; | |
1398 | if (!pte_none(*pte)) | |
1399 | goto out_unlock; | |
1400 | ||
1401 | /* Ok, finally just insert the thing.. */ | |
1402 | entry = pte_mkspecial(pfn_pte(pfn, prot)); | |
1403 | set_pte_at(mm, addr, pte, entry); | |
1404 | update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */ | |
1405 | ||
1406 | retval = 0; | |
1407 | out_unlock: | |
1408 | pte_unmap_unlock(pte, ptl); | |
1409 | out: | |
1410 | return retval; | |
1411 | } | |
1412 | ||
e0dc0d8f NP |
1413 | /** |
1414 | * vm_insert_pfn - insert single pfn into user vma | |
1415 | * @vma: user vma to map to | |
1416 | * @addr: target user address of this page | |
1417 | * @pfn: source kernel pfn | |
1418 | * | |
1419 | * Similar to vm_inert_page, this allows drivers to insert individual pages | |
1420 | * they've allocated into a user vma. Same comments apply. | |
1421 | * | |
1422 | * This function should only be called from a vm_ops->fault handler, and | |
1423 | * in that case the handler should return NULL. | |
0d71d10a NP |
1424 | * |
1425 | * vma cannot be a COW mapping. | |
1426 | * | |
1427 | * As this is called only for pages that do not currently exist, we | |
1428 | * do not need to flush old virtual caches or the TLB. | |
e0dc0d8f NP |
1429 | */ |
1430 | int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr, | |
423bad60 | 1431 | unsigned long pfn) |
e0dc0d8f | 1432 | { |
7e675137 NP |
1433 | /* |
1434 | * Technically, architectures with pte_special can avoid all these | |
1435 | * restrictions (same for remap_pfn_range). However we would like | |
1436 | * consistency in testing and feature parity among all, so we should | |
1437 | * try to keep these invariants in place for everybody. | |
1438 | */ | |
b379d790 JH |
1439 | BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))); |
1440 | BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) == | |
1441 | (VM_PFNMAP|VM_MIXEDMAP)); | |
1442 | BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags)); | |
1443 | BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn)); | |
e0dc0d8f | 1444 | |
423bad60 NP |
1445 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1446 | return -EFAULT; | |
1447 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
1448 | } | |
1449 | EXPORT_SYMBOL(vm_insert_pfn); | |
e0dc0d8f | 1450 | |
423bad60 NP |
1451 | int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr, |
1452 | unsigned long pfn) | |
1453 | { | |
1454 | BUG_ON(!(vma->vm_flags & VM_MIXEDMAP)); | |
e0dc0d8f | 1455 | |
423bad60 NP |
1456 | if (addr < vma->vm_start || addr >= vma->vm_end) |
1457 | return -EFAULT; | |
e0dc0d8f | 1458 | |
423bad60 NP |
1459 | /* |
1460 | * If we don't have pte special, then we have to use the pfn_valid() | |
1461 | * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must* | |
1462 | * refcount the page if pfn_valid is true (hence insert_page rather | |
1463 | * than insert_pfn). | |
1464 | */ | |
1465 | if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) { | |
1466 | struct page *page; | |
1467 | ||
1468 | page = pfn_to_page(pfn); | |
1469 | return insert_page(vma, addr, page, vma->vm_page_prot); | |
1470 | } | |
1471 | return insert_pfn(vma, addr, pfn, vma->vm_page_prot); | |
e0dc0d8f | 1472 | } |
423bad60 | 1473 | EXPORT_SYMBOL(vm_insert_mixed); |
e0dc0d8f | 1474 | |
1da177e4 LT |
1475 | /* |
1476 | * maps a range of physical memory into the requested pages. the old | |
1477 | * mappings are removed. any references to nonexistent pages results | |
1478 | * in null mappings (currently treated as "copy-on-access") | |
1479 | */ | |
1480 | static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd, | |
1481 | unsigned long addr, unsigned long end, | |
1482 | unsigned long pfn, pgprot_t prot) | |
1483 | { | |
1484 | pte_t *pte; | |
c74df32c | 1485 | spinlock_t *ptl; |
1da177e4 | 1486 | |
c74df32c | 1487 | pte = pte_alloc_map_lock(mm, pmd, addr, &ptl); |
1da177e4 LT |
1488 | if (!pte) |
1489 | return -ENOMEM; | |
6606c3e0 | 1490 | arch_enter_lazy_mmu_mode(); |
1da177e4 LT |
1491 | do { |
1492 | BUG_ON(!pte_none(*pte)); | |
7e675137 | 1493 | set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot))); |
1da177e4 LT |
1494 | pfn++; |
1495 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
6606c3e0 | 1496 | arch_leave_lazy_mmu_mode(); |
c74df32c | 1497 | pte_unmap_unlock(pte - 1, ptl); |
1da177e4 LT |
1498 | return 0; |
1499 | } | |
1500 | ||
1501 | static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1502 | unsigned long addr, unsigned long end, | |
1503 | unsigned long pfn, pgprot_t prot) | |
1504 | { | |
1505 | pmd_t *pmd; | |
1506 | unsigned long next; | |
1507 | ||
1508 | pfn -= addr >> PAGE_SHIFT; | |
1509 | pmd = pmd_alloc(mm, pud, addr); | |
1510 | if (!pmd) | |
1511 | return -ENOMEM; | |
1512 | do { | |
1513 | next = pmd_addr_end(addr, end); | |
1514 | if (remap_pte_range(mm, pmd, addr, next, | |
1515 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1516 | return -ENOMEM; | |
1517 | } while (pmd++, addr = next, addr != end); | |
1518 | return 0; | |
1519 | } | |
1520 | ||
1521 | static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1522 | unsigned long addr, unsigned long end, | |
1523 | unsigned long pfn, pgprot_t prot) | |
1524 | { | |
1525 | pud_t *pud; | |
1526 | unsigned long next; | |
1527 | ||
1528 | pfn -= addr >> PAGE_SHIFT; | |
1529 | pud = pud_alloc(mm, pgd, addr); | |
1530 | if (!pud) | |
1531 | return -ENOMEM; | |
1532 | do { | |
1533 | next = pud_addr_end(addr, end); | |
1534 | if (remap_pmd_range(mm, pud, addr, next, | |
1535 | pfn + (addr >> PAGE_SHIFT), prot)) | |
1536 | return -ENOMEM; | |
1537 | } while (pud++, addr = next, addr != end); | |
1538 | return 0; | |
1539 | } | |
1540 | ||
bfa5bf6d REB |
1541 | /** |
1542 | * remap_pfn_range - remap kernel memory to userspace | |
1543 | * @vma: user vma to map to | |
1544 | * @addr: target user address to start at | |
1545 | * @pfn: physical address of kernel memory | |
1546 | * @size: size of map area | |
1547 | * @prot: page protection flags for this mapping | |
1548 | * | |
1549 | * Note: this is only safe if the mm semaphore is held when called. | |
1550 | */ | |
1da177e4 LT |
1551 | int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, |
1552 | unsigned long pfn, unsigned long size, pgprot_t prot) | |
1553 | { | |
1554 | pgd_t *pgd; | |
1555 | unsigned long next; | |
2d15cab8 | 1556 | unsigned long end = addr + PAGE_ALIGN(size); |
1da177e4 LT |
1557 | struct mm_struct *mm = vma->vm_mm; |
1558 | int err; | |
1559 | ||
1560 | /* | |
1561 | * Physically remapped pages are special. Tell the | |
1562 | * rest of the world about it: | |
1563 | * VM_IO tells people not to look at these pages | |
1564 | * (accesses can have side effects). | |
0b14c179 HD |
1565 | * VM_RESERVED is specified all over the place, because |
1566 | * in 2.4 it kept swapout's vma scan off this vma; but | |
1567 | * in 2.6 the LRU scan won't even find its pages, so this | |
1568 | * flag means no more than count its pages in reserved_vm, | |
1569 | * and omit it from core dump, even when VM_IO turned off. | |
6aab341e LT |
1570 | * VM_PFNMAP tells the core MM that the base pages are just |
1571 | * raw PFN mappings, and do not have a "struct page" associated | |
1572 | * with them. | |
fb155c16 LT |
1573 | * |
1574 | * There's a horrible special case to handle copy-on-write | |
1575 | * behaviour that some programs depend on. We mark the "original" | |
1576 | * un-COW'ed pages by matching them up with "vma->vm_pgoff". | |
1da177e4 | 1577 | */ |
67121172 | 1578 | if (is_cow_mapping(vma->vm_flags)) { |
fb155c16 | 1579 | if (addr != vma->vm_start || end != vma->vm_end) |
7fc7e2ee | 1580 | return -EINVAL; |
fb155c16 LT |
1581 | vma->vm_pgoff = pfn; |
1582 | } | |
1583 | ||
6aab341e | 1584 | vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP; |
1da177e4 LT |
1585 | |
1586 | BUG_ON(addr >= end); | |
1587 | pfn -= addr >> PAGE_SHIFT; | |
1588 | pgd = pgd_offset(mm, addr); | |
1589 | flush_cache_range(vma, addr, end); | |
1da177e4 LT |
1590 | do { |
1591 | next = pgd_addr_end(addr, end); | |
1592 | err = remap_pud_range(mm, pgd, addr, next, | |
1593 | pfn + (addr >> PAGE_SHIFT), prot); | |
1594 | if (err) | |
1595 | break; | |
1596 | } while (pgd++, addr = next, addr != end); | |
1da177e4 LT |
1597 | return err; |
1598 | } | |
1599 | EXPORT_SYMBOL(remap_pfn_range); | |
1600 | ||
aee16b3c JF |
1601 | static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd, |
1602 | unsigned long addr, unsigned long end, | |
1603 | pte_fn_t fn, void *data) | |
1604 | { | |
1605 | pte_t *pte; | |
1606 | int err; | |
2f569afd | 1607 | pgtable_t token; |
94909914 | 1608 | spinlock_t *uninitialized_var(ptl); |
aee16b3c JF |
1609 | |
1610 | pte = (mm == &init_mm) ? | |
1611 | pte_alloc_kernel(pmd, addr) : | |
1612 | pte_alloc_map_lock(mm, pmd, addr, &ptl); | |
1613 | if (!pte) | |
1614 | return -ENOMEM; | |
1615 | ||
1616 | BUG_ON(pmd_huge(*pmd)); | |
1617 | ||
2f569afd | 1618 | token = pmd_pgtable(*pmd); |
aee16b3c JF |
1619 | |
1620 | do { | |
2f569afd | 1621 | err = fn(pte, token, addr, data); |
aee16b3c JF |
1622 | if (err) |
1623 | break; | |
1624 | } while (pte++, addr += PAGE_SIZE, addr != end); | |
1625 | ||
1626 | if (mm != &init_mm) | |
1627 | pte_unmap_unlock(pte-1, ptl); | |
1628 | return err; | |
1629 | } | |
1630 | ||
1631 | static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud, | |
1632 | unsigned long addr, unsigned long end, | |
1633 | pte_fn_t fn, void *data) | |
1634 | { | |
1635 | pmd_t *pmd; | |
1636 | unsigned long next; | |
1637 | int err; | |
1638 | ||
ceb86879 AK |
1639 | BUG_ON(pud_huge(*pud)); |
1640 | ||
aee16b3c JF |
1641 | pmd = pmd_alloc(mm, pud, addr); |
1642 | if (!pmd) | |
1643 | return -ENOMEM; | |
1644 | do { | |
1645 | next = pmd_addr_end(addr, end); | |
1646 | err = apply_to_pte_range(mm, pmd, addr, next, fn, data); | |
1647 | if (err) | |
1648 | break; | |
1649 | } while (pmd++, addr = next, addr != end); | |
1650 | return err; | |
1651 | } | |
1652 | ||
1653 | static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd, | |
1654 | unsigned long addr, unsigned long end, | |
1655 | pte_fn_t fn, void *data) | |
1656 | { | |
1657 | pud_t *pud; | |
1658 | unsigned long next; | |
1659 | int err; | |
1660 | ||
1661 | pud = pud_alloc(mm, pgd, addr); | |
1662 | if (!pud) | |
1663 | return -ENOMEM; | |
1664 | do { | |
1665 | next = pud_addr_end(addr, end); | |
1666 | err = apply_to_pmd_range(mm, pud, addr, next, fn, data); | |
1667 | if (err) | |
1668 | break; | |
1669 | } while (pud++, addr = next, addr != end); | |
1670 | return err; | |
1671 | } | |
1672 | ||
1673 | /* | |
1674 | * Scan a region of virtual memory, filling in page tables as necessary | |
1675 | * and calling a provided function on each leaf page table. | |
1676 | */ | |
1677 | int apply_to_page_range(struct mm_struct *mm, unsigned long addr, | |
1678 | unsigned long size, pte_fn_t fn, void *data) | |
1679 | { | |
1680 | pgd_t *pgd; | |
1681 | unsigned long next; | |
cddb8a5c | 1682 | unsigned long start = addr, end = addr + size; |
aee16b3c JF |
1683 | int err; |
1684 | ||
1685 | BUG_ON(addr >= end); | |
cddb8a5c | 1686 | mmu_notifier_invalidate_range_start(mm, start, end); |
aee16b3c JF |
1687 | pgd = pgd_offset(mm, addr); |
1688 | do { | |
1689 | next = pgd_addr_end(addr, end); | |
1690 | err = apply_to_pud_range(mm, pgd, addr, next, fn, data); | |
1691 | if (err) | |
1692 | break; | |
1693 | } while (pgd++, addr = next, addr != end); | |
cddb8a5c | 1694 | mmu_notifier_invalidate_range_end(mm, start, end); |
aee16b3c JF |
1695 | return err; |
1696 | } | |
1697 | EXPORT_SYMBOL_GPL(apply_to_page_range); | |
1698 | ||
8f4e2101 HD |
1699 | /* |
1700 | * handle_pte_fault chooses page fault handler according to an entry | |
1701 | * which was read non-atomically. Before making any commitment, on | |
1702 | * those architectures or configurations (e.g. i386 with PAE) which | |
1703 | * might give a mix of unmatched parts, do_swap_page and do_file_page | |
1704 | * must check under lock before unmapping the pte and proceeding | |
1705 | * (but do_wp_page is only called after already making such a check; | |
1706 | * and do_anonymous_page and do_no_page can safely check later on). | |
1707 | */ | |
4c21e2f2 | 1708 | static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd, |
8f4e2101 HD |
1709 | pte_t *page_table, pte_t orig_pte) |
1710 | { | |
1711 | int same = 1; | |
1712 | #if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT) | |
1713 | if (sizeof(pte_t) > sizeof(unsigned long)) { | |
4c21e2f2 HD |
1714 | spinlock_t *ptl = pte_lockptr(mm, pmd); |
1715 | spin_lock(ptl); | |
8f4e2101 | 1716 | same = pte_same(*page_table, orig_pte); |
4c21e2f2 | 1717 | spin_unlock(ptl); |
8f4e2101 HD |
1718 | } |
1719 | #endif | |
1720 | pte_unmap(page_table); | |
1721 | return same; | |
1722 | } | |
1723 | ||
1da177e4 LT |
1724 | /* |
1725 | * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when | |
1726 | * servicing faults for write access. In the normal case, do always want | |
1727 | * pte_mkwrite. But get_user_pages can cause write faults for mappings | |
1728 | * that do not have writing enabled, when used by access_process_vm. | |
1729 | */ | |
1730 | static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma) | |
1731 | { | |
1732 | if (likely(vma->vm_flags & VM_WRITE)) | |
1733 | pte = pte_mkwrite(pte); | |
1734 | return pte; | |
1735 | } | |
1736 | ||
9de455b2 | 1737 | static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma) |
6aab341e LT |
1738 | { |
1739 | /* | |
1740 | * If the source page was a PFN mapping, we don't have | |
1741 | * a "struct page" for it. We do a best-effort copy by | |
1742 | * just copying from the original user address. If that | |
1743 | * fails, we just zero-fill it. Live with it. | |
1744 | */ | |
1745 | if (unlikely(!src)) { | |
1746 | void *kaddr = kmap_atomic(dst, KM_USER0); | |
5d2a2dbb LT |
1747 | void __user *uaddr = (void __user *)(va & PAGE_MASK); |
1748 | ||
1749 | /* | |
1750 | * This really shouldn't fail, because the page is there | |
1751 | * in the page tables. But it might just be unreadable, | |
1752 | * in which case we just give up and fill the result with | |
1753 | * zeroes. | |
1754 | */ | |
1755 | if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE)) | |
6aab341e LT |
1756 | memset(kaddr, 0, PAGE_SIZE); |
1757 | kunmap_atomic(kaddr, KM_USER0); | |
c4ec7b0d | 1758 | flush_dcache_page(dst); |
0ed361de NP |
1759 | } else |
1760 | copy_user_highpage(dst, src, va, vma); | |
6aab341e LT |
1761 | } |
1762 | ||
1da177e4 LT |
1763 | /* |
1764 | * This routine handles present pages, when users try to write | |
1765 | * to a shared page. It is done by copying the page to a new address | |
1766 | * and decrementing the shared-page counter for the old page. | |
1767 | * | |
1da177e4 LT |
1768 | * Note that this routine assumes that the protection checks have been |
1769 | * done by the caller (the low-level page fault routine in most cases). | |
1770 | * Thus we can safely just mark it writable once we've done any necessary | |
1771 | * COW. | |
1772 | * | |
1773 | * We also mark the page dirty at this point even though the page will | |
1774 | * change only once the write actually happens. This avoids a few races, | |
1775 | * and potentially makes it more efficient. | |
1776 | * | |
8f4e2101 HD |
1777 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
1778 | * but allow concurrent faults), with pte both mapped and locked. | |
1779 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 1780 | */ |
65500d23 HD |
1781 | static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma, |
1782 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
8f4e2101 | 1783 | spinlock_t *ptl, pte_t orig_pte) |
1da177e4 | 1784 | { |
e5bbe4df | 1785 | struct page *old_page, *new_page; |
1da177e4 | 1786 | pte_t entry; |
83c54070 | 1787 | int reuse = 0, ret = 0; |
a200ee18 | 1788 | int page_mkwrite = 0; |
d08b3851 | 1789 | struct page *dirty_page = NULL; |
1da177e4 | 1790 | |
6aab341e | 1791 | old_page = vm_normal_page(vma, address, orig_pte); |
251b97f5 PZ |
1792 | if (!old_page) { |
1793 | /* | |
1794 | * VM_MIXEDMAP !pfn_valid() case | |
1795 | * | |
1796 | * We should not cow pages in a shared writeable mapping. | |
1797 | * Just mark the pages writable as we can't do any dirty | |
1798 | * accounting on raw pfn maps. | |
1799 | */ | |
1800 | if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
1801 | (VM_WRITE|VM_SHARED)) | |
1802 | goto reuse; | |
6aab341e | 1803 | goto gotten; |
251b97f5 | 1804 | } |
1da177e4 | 1805 | |
d08b3851 | 1806 | /* |
ee6a6457 PZ |
1807 | * Take out anonymous pages first, anonymous shared vmas are |
1808 | * not dirty accountable. | |
d08b3851 | 1809 | */ |
ee6a6457 | 1810 | if (PageAnon(old_page)) { |
529ae9aa | 1811 | if (trylock_page(old_page)) { |
ee6a6457 PZ |
1812 | reuse = can_share_swap_page(old_page); |
1813 | unlock_page(old_page); | |
1814 | } | |
1815 | } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == | |
d08b3851 | 1816 | (VM_WRITE|VM_SHARED))) { |
ee6a6457 PZ |
1817 | /* |
1818 | * Only catch write-faults on shared writable pages, | |
1819 | * read-only shared pages can get COWed by | |
1820 | * get_user_pages(.write=1, .force=1). | |
1821 | */ | |
9637a5ef DH |
1822 | if (vma->vm_ops && vma->vm_ops->page_mkwrite) { |
1823 | /* | |
1824 | * Notify the address space that the page is about to | |
1825 | * become writable so that it can prohibit this or wait | |
1826 | * for the page to get into an appropriate state. | |
1827 | * | |
1828 | * We do this without the lock held, so that it can | |
1829 | * sleep if it needs to. | |
1830 | */ | |
1831 | page_cache_get(old_page); | |
1832 | pte_unmap_unlock(page_table, ptl); | |
1833 | ||
1834 | if (vma->vm_ops->page_mkwrite(vma, old_page) < 0) | |
1835 | goto unwritable_page; | |
1836 | ||
9637a5ef DH |
1837 | /* |
1838 | * Since we dropped the lock we need to revalidate | |
1839 | * the PTE as someone else may have changed it. If | |
1840 | * they did, we just return, as we can count on the | |
1841 | * MMU to tell us if they didn't also make it writable. | |
1842 | */ | |
1843 | page_table = pte_offset_map_lock(mm, pmd, address, | |
1844 | &ptl); | |
c3704ceb | 1845 | page_cache_release(old_page); |
9637a5ef DH |
1846 | if (!pte_same(*page_table, orig_pte)) |
1847 | goto unlock; | |
a200ee18 PZ |
1848 | |
1849 | page_mkwrite = 1; | |
1da177e4 | 1850 | } |
d08b3851 PZ |
1851 | dirty_page = old_page; |
1852 | get_page(dirty_page); | |
9637a5ef | 1853 | reuse = 1; |
9637a5ef DH |
1854 | } |
1855 | ||
1856 | if (reuse) { | |
251b97f5 | 1857 | reuse: |
9637a5ef DH |
1858 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
1859 | entry = pte_mkyoung(orig_pte); | |
1860 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
954ffcb3 | 1861 | if (ptep_set_access_flags(vma, address, page_table, entry,1)) |
8dab5241 | 1862 | update_mmu_cache(vma, address, entry); |
9637a5ef DH |
1863 | ret |= VM_FAULT_WRITE; |
1864 | goto unlock; | |
1da177e4 | 1865 | } |
1da177e4 LT |
1866 | |
1867 | /* | |
1868 | * Ok, we need to copy. Oh, well.. | |
1869 | */ | |
b5810039 | 1870 | page_cache_get(old_page); |
920fc356 | 1871 | gotten: |
8f4e2101 | 1872 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
1873 | |
1874 | if (unlikely(anon_vma_prepare(vma))) | |
65500d23 | 1875 | goto oom; |
557ed1fa NP |
1876 | VM_BUG_ON(old_page == ZERO_PAGE(0)); |
1877 | new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address); | |
1878 | if (!new_page) | |
1879 | goto oom; | |
b291f000 NP |
1880 | /* |
1881 | * Don't let another task, with possibly unlocked vma, | |
1882 | * keep the mlocked page. | |
1883 | */ | |
1884 | if (vma->vm_flags & VM_LOCKED) { | |
1885 | lock_page(old_page); /* for LRU manipulation */ | |
1886 | clear_page_mlock(old_page); | |
1887 | unlock_page(old_page); | |
1888 | } | |
557ed1fa | 1889 | cow_user_page(new_page, old_page, address, vma); |
0ed361de | 1890 | __SetPageUptodate(new_page); |
65500d23 | 1891 | |
e1a1cd59 | 1892 | if (mem_cgroup_charge(new_page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
1893 | goto oom_free_new; |
1894 | ||
1da177e4 LT |
1895 | /* |
1896 | * Re-check the pte - we dropped the lock | |
1897 | */ | |
8f4e2101 | 1898 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
65500d23 | 1899 | if (likely(pte_same(*page_table, orig_pte))) { |
920fc356 | 1900 | if (old_page) { |
920fc356 HD |
1901 | if (!PageAnon(old_page)) { |
1902 | dec_mm_counter(mm, file_rss); | |
1903 | inc_mm_counter(mm, anon_rss); | |
1904 | } | |
1905 | } else | |
4294621f | 1906 | inc_mm_counter(mm, anon_rss); |
eca35133 | 1907 | flush_cache_page(vma, address, pte_pfn(orig_pte)); |
65500d23 HD |
1908 | entry = mk_pte(new_page, vma->vm_page_prot); |
1909 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
4ce072f1 SS |
1910 | /* |
1911 | * Clear the pte entry and flush it first, before updating the | |
1912 | * pte with the new entry. This will avoid a race condition | |
1913 | * seen in the presence of one thread doing SMC and another | |
1914 | * thread doing COW. | |
1915 | */ | |
cddb8a5c | 1916 | ptep_clear_flush_notify(vma, address, page_table); |
b2e18538 | 1917 | SetPageSwapBacked(new_page); |
64d6519d | 1918 | lru_cache_add_active_or_unevictable(new_page, vma); |
9617d95e | 1919 | page_add_new_anon_rmap(new_page, vma, address); |
1da177e4 | 1920 | |
64d6519d LS |
1921 | //TODO: is this safe? do_anonymous_page() does it this way. |
1922 | set_pte_at(mm, address, page_table, entry); | |
1923 | update_mmu_cache(vma, address, entry); | |
945754a1 NP |
1924 | if (old_page) { |
1925 | /* | |
1926 | * Only after switching the pte to the new page may | |
1927 | * we remove the mapcount here. Otherwise another | |
1928 | * process may come and find the rmap count decremented | |
1929 | * before the pte is switched to the new page, and | |
1930 | * "reuse" the old page writing into it while our pte | |
1931 | * here still points into it and can be read by other | |
1932 | * threads. | |
1933 | * | |
1934 | * The critical issue is to order this | |
1935 | * page_remove_rmap with the ptp_clear_flush above. | |
1936 | * Those stores are ordered by (if nothing else,) | |
1937 | * the barrier present in the atomic_add_negative | |
1938 | * in page_remove_rmap. | |
1939 | * | |
1940 | * Then the TLB flush in ptep_clear_flush ensures that | |
1941 | * no process can access the old page before the | |
1942 | * decremented mapcount is visible. And the old page | |
1943 | * cannot be reused until after the decremented | |
1944 | * mapcount is visible. So transitively, TLBs to | |
1945 | * old page will be flushed before it can be reused. | |
1946 | */ | |
1947 | page_remove_rmap(old_page, vma); | |
1948 | } | |
1949 | ||
1da177e4 LT |
1950 | /* Free the old page.. */ |
1951 | new_page = old_page; | |
f33ea7f4 | 1952 | ret |= VM_FAULT_WRITE; |
8a9f3ccd BS |
1953 | } else |
1954 | mem_cgroup_uncharge_page(new_page); | |
1955 | ||
920fc356 HD |
1956 | if (new_page) |
1957 | page_cache_release(new_page); | |
1958 | if (old_page) | |
1959 | page_cache_release(old_page); | |
65500d23 | 1960 | unlock: |
8f4e2101 | 1961 | pte_unmap_unlock(page_table, ptl); |
d08b3851 | 1962 | if (dirty_page) { |
8f7b3d15 AS |
1963 | if (vma->vm_file) |
1964 | file_update_time(vma->vm_file); | |
1965 | ||
79352894 NP |
1966 | /* |
1967 | * Yes, Virginia, this is actually required to prevent a race | |
1968 | * with clear_page_dirty_for_io() from clearing the page dirty | |
1969 | * bit after it clear all dirty ptes, but before a racing | |
1970 | * do_wp_page installs a dirty pte. | |
1971 | * | |
1972 | * do_no_page is protected similarly. | |
1973 | */ | |
1974 | wait_on_page_locked(dirty_page); | |
a200ee18 | 1975 | set_page_dirty_balance(dirty_page, page_mkwrite); |
d08b3851 PZ |
1976 | put_page(dirty_page); |
1977 | } | |
f33ea7f4 | 1978 | return ret; |
8a9f3ccd | 1979 | oom_free_new: |
6dbf6d3b | 1980 | page_cache_release(new_page); |
65500d23 | 1981 | oom: |
920fc356 HD |
1982 | if (old_page) |
1983 | page_cache_release(old_page); | |
1da177e4 | 1984 | return VM_FAULT_OOM; |
9637a5ef DH |
1985 | |
1986 | unwritable_page: | |
1987 | page_cache_release(old_page); | |
1988 | return VM_FAULT_SIGBUS; | |
1da177e4 LT |
1989 | } |
1990 | ||
1991 | /* | |
1992 | * Helper functions for unmap_mapping_range(). | |
1993 | * | |
1994 | * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __ | |
1995 | * | |
1996 | * We have to restart searching the prio_tree whenever we drop the lock, | |
1997 | * since the iterator is only valid while the lock is held, and anyway | |
1998 | * a later vma might be split and reinserted earlier while lock dropped. | |
1999 | * | |
2000 | * The list of nonlinear vmas could be handled more efficiently, using | |
2001 | * a placeholder, but handle it in the same way until a need is shown. | |
2002 | * It is important to search the prio_tree before nonlinear list: a vma | |
2003 | * may become nonlinear and be shifted from prio_tree to nonlinear list | |
2004 | * while the lock is dropped; but never shifted from list to prio_tree. | |
2005 | * | |
2006 | * In order to make forward progress despite restarting the search, | |
2007 | * vm_truncate_count is used to mark a vma as now dealt with, so we can | |
2008 | * quickly skip it next time around. Since the prio_tree search only | |
2009 | * shows us those vmas affected by unmapping the range in question, we | |
2010 | * can't efficiently keep all vmas in step with mapping->truncate_count: | |
2011 | * so instead reset them all whenever it wraps back to 0 (then go to 1). | |
2012 | * mapping->truncate_count and vma->vm_truncate_count are protected by | |
2013 | * i_mmap_lock. | |
2014 | * | |
2015 | * In order to make forward progress despite repeatedly restarting some | |
ee39b37b | 2016 | * large vma, note the restart_addr from unmap_vmas when it breaks out: |
1da177e4 LT |
2017 | * and restart from that address when we reach that vma again. It might |
2018 | * have been split or merged, shrunk or extended, but never shifted: so | |
2019 | * restart_addr remains valid so long as it remains in the vma's range. | |
2020 | * unmap_mapping_range forces truncate_count to leap over page-aligned | |
2021 | * values so we can save vma's restart_addr in its truncate_count field. | |
2022 | */ | |
2023 | #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK)) | |
2024 | ||
2025 | static void reset_vma_truncate_counts(struct address_space *mapping) | |
2026 | { | |
2027 | struct vm_area_struct *vma; | |
2028 | struct prio_tree_iter iter; | |
2029 | ||
2030 | vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX) | |
2031 | vma->vm_truncate_count = 0; | |
2032 | list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list) | |
2033 | vma->vm_truncate_count = 0; | |
2034 | } | |
2035 | ||
2036 | static int unmap_mapping_range_vma(struct vm_area_struct *vma, | |
2037 | unsigned long start_addr, unsigned long end_addr, | |
2038 | struct zap_details *details) | |
2039 | { | |
2040 | unsigned long restart_addr; | |
2041 | int need_break; | |
2042 | ||
d00806b1 NP |
2043 | /* |
2044 | * files that support invalidating or truncating portions of the | |
d0217ac0 | 2045 | * file from under mmaped areas must have their ->fault function |
83c54070 NP |
2046 | * return a locked page (and set VM_FAULT_LOCKED in the return). |
2047 | * This provides synchronisation against concurrent unmapping here. | |
d00806b1 | 2048 | */ |
d00806b1 | 2049 | |
1da177e4 LT |
2050 | again: |
2051 | restart_addr = vma->vm_truncate_count; | |
2052 | if (is_restart_addr(restart_addr) && start_addr < restart_addr) { | |
2053 | start_addr = restart_addr; | |
2054 | if (start_addr >= end_addr) { | |
2055 | /* Top of vma has been split off since last time */ | |
2056 | vma->vm_truncate_count = details->truncate_count; | |
2057 | return 0; | |
2058 | } | |
2059 | } | |
2060 | ||
ee39b37b HD |
2061 | restart_addr = zap_page_range(vma, start_addr, |
2062 | end_addr - start_addr, details); | |
95c354fe | 2063 | need_break = need_resched() || spin_needbreak(details->i_mmap_lock); |
1da177e4 | 2064 | |
ee39b37b | 2065 | if (restart_addr >= end_addr) { |
1da177e4 LT |
2066 | /* We have now completed this vma: mark it so */ |
2067 | vma->vm_truncate_count = details->truncate_count; | |
2068 | if (!need_break) | |
2069 | return 0; | |
2070 | } else { | |
2071 | /* Note restart_addr in vma's truncate_count field */ | |
ee39b37b | 2072 | vma->vm_truncate_count = restart_addr; |
1da177e4 LT |
2073 | if (!need_break) |
2074 | goto again; | |
2075 | } | |
2076 | ||
2077 | spin_unlock(details->i_mmap_lock); | |
2078 | cond_resched(); | |
2079 | spin_lock(details->i_mmap_lock); | |
2080 | return -EINTR; | |
2081 | } | |
2082 | ||
2083 | static inline void unmap_mapping_range_tree(struct prio_tree_root *root, | |
2084 | struct zap_details *details) | |
2085 | { | |
2086 | struct vm_area_struct *vma; | |
2087 | struct prio_tree_iter iter; | |
2088 | pgoff_t vba, vea, zba, zea; | |
2089 | ||
2090 | restart: | |
2091 | vma_prio_tree_foreach(vma, &iter, root, | |
2092 | details->first_index, details->last_index) { | |
2093 | /* Skip quickly over those we have already dealt with */ | |
2094 | if (vma->vm_truncate_count == details->truncate_count) | |
2095 | continue; | |
2096 | ||
2097 | vba = vma->vm_pgoff; | |
2098 | vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1; | |
2099 | /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */ | |
2100 | zba = details->first_index; | |
2101 | if (zba < vba) | |
2102 | zba = vba; | |
2103 | zea = details->last_index; | |
2104 | if (zea > vea) | |
2105 | zea = vea; | |
2106 | ||
2107 | if (unmap_mapping_range_vma(vma, | |
2108 | ((zba - vba) << PAGE_SHIFT) + vma->vm_start, | |
2109 | ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start, | |
2110 | details) < 0) | |
2111 | goto restart; | |
2112 | } | |
2113 | } | |
2114 | ||
2115 | static inline void unmap_mapping_range_list(struct list_head *head, | |
2116 | struct zap_details *details) | |
2117 | { | |
2118 | struct vm_area_struct *vma; | |
2119 | ||
2120 | /* | |
2121 | * In nonlinear VMAs there is no correspondence between virtual address | |
2122 | * offset and file offset. So we must perform an exhaustive search | |
2123 | * across *all* the pages in each nonlinear VMA, not just the pages | |
2124 | * whose virtual address lies outside the file truncation point. | |
2125 | */ | |
2126 | restart: | |
2127 | list_for_each_entry(vma, head, shared.vm_set.list) { | |
2128 | /* Skip quickly over those we have already dealt with */ | |
2129 | if (vma->vm_truncate_count == details->truncate_count) | |
2130 | continue; | |
2131 | details->nonlinear_vma = vma; | |
2132 | if (unmap_mapping_range_vma(vma, vma->vm_start, | |
2133 | vma->vm_end, details) < 0) | |
2134 | goto restart; | |
2135 | } | |
2136 | } | |
2137 | ||
2138 | /** | |
72fd4a35 | 2139 | * 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 | 2140 | * @mapping: the address space containing mmaps to be unmapped. |
1da177e4 LT |
2141 | * @holebegin: byte in first page to unmap, relative to the start of |
2142 | * the underlying file. This will be rounded down to a PAGE_SIZE | |
2143 | * boundary. Note that this is different from vmtruncate(), which | |
2144 | * must keep the partial page. In contrast, we must get rid of | |
2145 | * partial pages. | |
2146 | * @holelen: size of prospective hole in bytes. This will be rounded | |
2147 | * up to a PAGE_SIZE boundary. A holelen of zero truncates to the | |
2148 | * end of the file. | |
2149 | * @even_cows: 1 when truncating a file, unmap even private COWed pages; | |
2150 | * but 0 when invalidating pagecache, don't throw away private data. | |
2151 | */ | |
2152 | void unmap_mapping_range(struct address_space *mapping, | |
2153 | loff_t const holebegin, loff_t const holelen, int even_cows) | |
2154 | { | |
2155 | struct zap_details details; | |
2156 | pgoff_t hba = holebegin >> PAGE_SHIFT; | |
2157 | pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2158 | ||
2159 | /* Check for overflow. */ | |
2160 | if (sizeof(holelen) > sizeof(hlen)) { | |
2161 | long long holeend = | |
2162 | (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
2163 | if (holeend & ~(long long)ULONG_MAX) | |
2164 | hlen = ULONG_MAX - hba + 1; | |
2165 | } | |
2166 | ||
2167 | details.check_mapping = even_cows? NULL: mapping; | |
2168 | details.nonlinear_vma = NULL; | |
2169 | details.first_index = hba; | |
2170 | details.last_index = hba + hlen - 1; | |
2171 | if (details.last_index < details.first_index) | |
2172 | details.last_index = ULONG_MAX; | |
2173 | details.i_mmap_lock = &mapping->i_mmap_lock; | |
2174 | ||
2175 | spin_lock(&mapping->i_mmap_lock); | |
2176 | ||
d00806b1 | 2177 | /* Protect against endless unmapping loops */ |
1da177e4 | 2178 | mapping->truncate_count++; |
1da177e4 LT |
2179 | if (unlikely(is_restart_addr(mapping->truncate_count))) { |
2180 | if (mapping->truncate_count == 0) | |
2181 | reset_vma_truncate_counts(mapping); | |
2182 | mapping->truncate_count++; | |
2183 | } | |
2184 | details.truncate_count = mapping->truncate_count; | |
2185 | ||
2186 | if (unlikely(!prio_tree_empty(&mapping->i_mmap))) | |
2187 | unmap_mapping_range_tree(&mapping->i_mmap, &details); | |
2188 | if (unlikely(!list_empty(&mapping->i_mmap_nonlinear))) | |
2189 | unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details); | |
2190 | spin_unlock(&mapping->i_mmap_lock); | |
2191 | } | |
2192 | EXPORT_SYMBOL(unmap_mapping_range); | |
2193 | ||
bfa5bf6d REB |
2194 | /** |
2195 | * vmtruncate - unmap mappings "freed" by truncate() syscall | |
2196 | * @inode: inode of the file used | |
2197 | * @offset: file offset to start truncating | |
1da177e4 LT |
2198 | * |
2199 | * NOTE! We have to be ready to update the memory sharing | |
2200 | * between the file and the memory map for a potential last | |
2201 | * incomplete page. Ugly, but necessary. | |
2202 | */ | |
2203 | int vmtruncate(struct inode * inode, loff_t offset) | |
2204 | { | |
61d5048f CH |
2205 | if (inode->i_size < offset) { |
2206 | unsigned long limit; | |
2207 | ||
2208 | limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur; | |
2209 | if (limit != RLIM_INFINITY && offset > limit) | |
2210 | goto out_sig; | |
2211 | if (offset > inode->i_sb->s_maxbytes) | |
2212 | goto out_big; | |
2213 | i_size_write(inode, offset); | |
2214 | } else { | |
2215 | struct address_space *mapping = inode->i_mapping; | |
1da177e4 | 2216 | |
61d5048f CH |
2217 | /* |
2218 | * truncation of in-use swapfiles is disallowed - it would | |
2219 | * cause subsequent swapout to scribble on the now-freed | |
2220 | * blocks. | |
2221 | */ | |
2222 | if (IS_SWAPFILE(inode)) | |
2223 | return -ETXTBSY; | |
2224 | i_size_write(inode, offset); | |
2225 | ||
2226 | /* | |
2227 | * unmap_mapping_range is called twice, first simply for | |
2228 | * efficiency so that truncate_inode_pages does fewer | |
2229 | * single-page unmaps. However after this first call, and | |
2230 | * before truncate_inode_pages finishes, it is possible for | |
2231 | * private pages to be COWed, which remain after | |
2232 | * truncate_inode_pages finishes, hence the second | |
2233 | * unmap_mapping_range call must be made for correctness. | |
2234 | */ | |
2235 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
2236 | truncate_inode_pages(mapping, offset); | |
2237 | unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1); | |
2238 | } | |
d00806b1 | 2239 | |
1da177e4 LT |
2240 | if (inode->i_op && inode->i_op->truncate) |
2241 | inode->i_op->truncate(inode); | |
2242 | return 0; | |
61d5048f | 2243 | |
1da177e4 LT |
2244 | out_sig: |
2245 | send_sig(SIGXFSZ, current, 0); | |
2246 | out_big: | |
2247 | return -EFBIG; | |
1da177e4 | 2248 | } |
1da177e4 LT |
2249 | EXPORT_SYMBOL(vmtruncate); |
2250 | ||
f6b3ec23 BP |
2251 | int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end) |
2252 | { | |
2253 | struct address_space *mapping = inode->i_mapping; | |
2254 | ||
2255 | /* | |
2256 | * If the underlying filesystem is not going to provide | |
2257 | * a way to truncate a range of blocks (punch a hole) - | |
2258 | * we should return failure right now. | |
2259 | */ | |
2260 | if (!inode->i_op || !inode->i_op->truncate_range) | |
2261 | return -ENOSYS; | |
2262 | ||
1b1dcc1b | 2263 | mutex_lock(&inode->i_mutex); |
f6b3ec23 BP |
2264 | down_write(&inode->i_alloc_sem); |
2265 | unmap_mapping_range(mapping, offset, (end - offset), 1); | |
2266 | truncate_inode_pages_range(mapping, offset, end); | |
d00806b1 | 2267 | unmap_mapping_range(mapping, offset, (end - offset), 1); |
f6b3ec23 BP |
2268 | inode->i_op->truncate_range(inode, offset, end); |
2269 | up_write(&inode->i_alloc_sem); | |
1b1dcc1b | 2270 | mutex_unlock(&inode->i_mutex); |
f6b3ec23 BP |
2271 | |
2272 | return 0; | |
2273 | } | |
f6b3ec23 | 2274 | |
1da177e4 | 2275 | /* |
8f4e2101 HD |
2276 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2277 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2278 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2279 | */ |
65500d23 HD |
2280 | static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2281 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2282 | int write_access, pte_t orig_pte) | |
1da177e4 | 2283 | { |
8f4e2101 | 2284 | spinlock_t *ptl; |
1da177e4 | 2285 | struct page *page; |
65500d23 | 2286 | swp_entry_t entry; |
1da177e4 | 2287 | pte_t pte; |
83c54070 | 2288 | int ret = 0; |
1da177e4 | 2289 | |
4c21e2f2 | 2290 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
8f4e2101 | 2291 | goto out; |
65500d23 HD |
2292 | |
2293 | entry = pte_to_swp_entry(orig_pte); | |
0697212a CL |
2294 | if (is_migration_entry(entry)) { |
2295 | migration_entry_wait(mm, pmd, address); | |
2296 | goto out; | |
2297 | } | |
0ff92245 | 2298 | delayacct_set_flag(DELAYACCT_PF_SWAPIN); |
1da177e4 LT |
2299 | page = lookup_swap_cache(entry); |
2300 | if (!page) { | |
098fe651 | 2301 | grab_swap_token(); /* Contend for token _before_ read-in */ |
02098fea HD |
2302 | page = swapin_readahead(entry, |
2303 | GFP_HIGHUSER_MOVABLE, vma, address); | |
1da177e4 LT |
2304 | if (!page) { |
2305 | /* | |
8f4e2101 HD |
2306 | * Back out if somebody else faulted in this pte |
2307 | * while we released the pte lock. | |
1da177e4 | 2308 | */ |
8f4e2101 | 2309 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2310 | if (likely(pte_same(*page_table, orig_pte))) |
2311 | ret = VM_FAULT_OOM; | |
0ff92245 | 2312 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); |
65500d23 | 2313 | goto unlock; |
1da177e4 LT |
2314 | } |
2315 | ||
2316 | /* Had to read the page from swap area: Major fault */ | |
2317 | ret = VM_FAULT_MAJOR; | |
f8891e5e | 2318 | count_vm_event(PGMAJFAULT); |
1da177e4 LT |
2319 | } |
2320 | ||
073e587e KH |
2321 | mark_page_accessed(page); |
2322 | ||
2323 | lock_page(page); | |
2324 | delayacct_clear_flag(DELAYACCT_PF_SWAPIN); | |
2325 | ||
e1a1cd59 | 2326 | if (mem_cgroup_charge(page, mm, GFP_KERNEL)) { |
8a9f3ccd | 2327 | ret = VM_FAULT_OOM; |
073e587e | 2328 | unlock_page(page); |
8a9f3ccd BS |
2329 | goto out; |
2330 | } | |
2331 | ||
1da177e4 | 2332 | /* |
8f4e2101 | 2333 | * Back out if somebody else already faulted in this pte. |
1da177e4 | 2334 | */ |
8f4e2101 | 2335 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
9e9bef07 | 2336 | if (unlikely(!pte_same(*page_table, orig_pte))) |
b8107480 | 2337 | goto out_nomap; |
b8107480 KK |
2338 | |
2339 | if (unlikely(!PageUptodate(page))) { | |
2340 | ret = VM_FAULT_SIGBUS; | |
2341 | goto out_nomap; | |
1da177e4 LT |
2342 | } |
2343 | ||
2344 | /* The page isn't present yet, go ahead with the fault. */ | |
1da177e4 | 2345 | |
4294621f | 2346 | inc_mm_counter(mm, anon_rss); |
1da177e4 LT |
2347 | pte = mk_pte(page, vma->vm_page_prot); |
2348 | if (write_access && can_share_swap_page(page)) { | |
2349 | pte = maybe_mkwrite(pte_mkdirty(pte), vma); | |
2350 | write_access = 0; | |
2351 | } | |
1da177e4 LT |
2352 | |
2353 | flush_icache_page(vma, page); | |
2354 | set_pte_at(mm, address, page_table, pte); | |
2355 | page_add_anon_rmap(page, vma, address); | |
2356 | ||
c475a8ab | 2357 | swap_free(entry); |
b291f000 | 2358 | if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page)) |
c475a8ab HD |
2359 | remove_exclusive_swap_page(page); |
2360 | unlock_page(page); | |
2361 | ||
1da177e4 | 2362 | if (write_access) { |
61469f1d HD |
2363 | ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte); |
2364 | if (ret & VM_FAULT_ERROR) | |
2365 | ret &= VM_FAULT_ERROR; | |
1da177e4 LT |
2366 | goto out; |
2367 | } | |
2368 | ||
2369 | /* No need to invalidate - it was non-present before */ | |
2370 | update_mmu_cache(vma, address, pte); | |
65500d23 | 2371 | unlock: |
8f4e2101 | 2372 | pte_unmap_unlock(page_table, ptl); |
1da177e4 LT |
2373 | out: |
2374 | return ret; | |
b8107480 | 2375 | out_nomap: |
8a9f3ccd | 2376 | mem_cgroup_uncharge_page(page); |
8f4e2101 | 2377 | pte_unmap_unlock(page_table, ptl); |
b8107480 KK |
2378 | unlock_page(page); |
2379 | page_cache_release(page); | |
65500d23 | 2380 | return ret; |
1da177e4 LT |
2381 | } |
2382 | ||
2383 | /* | |
8f4e2101 HD |
2384 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2385 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2386 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2387 | */ |
65500d23 HD |
2388 | static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma, |
2389 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2390 | int write_access) | |
1da177e4 | 2391 | { |
8f4e2101 HD |
2392 | struct page *page; |
2393 | spinlock_t *ptl; | |
1da177e4 | 2394 | pte_t entry; |
1da177e4 | 2395 | |
557ed1fa NP |
2396 | /* Allocate our own private page. */ |
2397 | pte_unmap(page_table); | |
8f4e2101 | 2398 | |
557ed1fa NP |
2399 | if (unlikely(anon_vma_prepare(vma))) |
2400 | goto oom; | |
2401 | page = alloc_zeroed_user_highpage_movable(vma, address); | |
2402 | if (!page) | |
2403 | goto oom; | |
0ed361de | 2404 | __SetPageUptodate(page); |
8f4e2101 | 2405 | |
e1a1cd59 | 2406 | if (mem_cgroup_charge(page, mm, GFP_KERNEL)) |
8a9f3ccd BS |
2407 | goto oom_free_page; |
2408 | ||
557ed1fa NP |
2409 | entry = mk_pte(page, vma->vm_page_prot); |
2410 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); | |
1da177e4 | 2411 | |
557ed1fa NP |
2412 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
2413 | if (!pte_none(*page_table)) | |
2414 | goto release; | |
2415 | inc_mm_counter(mm, anon_rss); | |
b2e18538 | 2416 | SetPageSwapBacked(page); |
64d6519d | 2417 | lru_cache_add_active_or_unevictable(page, vma); |
557ed1fa | 2418 | page_add_new_anon_rmap(page, vma, address); |
65500d23 | 2419 | set_pte_at(mm, address, page_table, entry); |
1da177e4 LT |
2420 | |
2421 | /* No need to invalidate - it was non-present before */ | |
65500d23 | 2422 | update_mmu_cache(vma, address, entry); |
65500d23 | 2423 | unlock: |
8f4e2101 | 2424 | pte_unmap_unlock(page_table, ptl); |
83c54070 | 2425 | return 0; |
8f4e2101 | 2426 | release: |
8a9f3ccd | 2427 | mem_cgroup_uncharge_page(page); |
8f4e2101 HD |
2428 | page_cache_release(page); |
2429 | goto unlock; | |
8a9f3ccd | 2430 | oom_free_page: |
6dbf6d3b | 2431 | page_cache_release(page); |
65500d23 | 2432 | oom: |
1da177e4 LT |
2433 | return VM_FAULT_OOM; |
2434 | } | |
2435 | ||
2436 | /* | |
54cb8821 | 2437 | * __do_fault() tries to create a new page mapping. It aggressively |
1da177e4 | 2438 | * tries to share with existing pages, but makes a separate copy if |
54cb8821 NP |
2439 | * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid |
2440 | * the next page fault. | |
1da177e4 LT |
2441 | * |
2442 | * As this is called only for pages that do not currently exist, we | |
2443 | * do not need to flush old virtual caches or the TLB. | |
2444 | * | |
8f4e2101 | 2445 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
16abfa08 | 2446 | * but allow concurrent faults), and pte neither mapped nor locked. |
8f4e2101 | 2447 | * We return with mmap_sem still held, but pte unmapped and unlocked. |
1da177e4 | 2448 | */ |
54cb8821 | 2449 | static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
16abfa08 | 2450 | unsigned long address, pmd_t *pmd, |
54cb8821 | 2451 | pgoff_t pgoff, unsigned int flags, pte_t orig_pte) |
1da177e4 | 2452 | { |
16abfa08 | 2453 | pte_t *page_table; |
8f4e2101 | 2454 | spinlock_t *ptl; |
d0217ac0 | 2455 | struct page *page; |
1da177e4 | 2456 | pte_t entry; |
1da177e4 | 2457 | int anon = 0; |
5b4e655e | 2458 | int charged = 0; |
d08b3851 | 2459 | struct page *dirty_page = NULL; |
d0217ac0 NP |
2460 | struct vm_fault vmf; |
2461 | int ret; | |
a200ee18 | 2462 | int page_mkwrite = 0; |
54cb8821 | 2463 | |
d0217ac0 NP |
2464 | vmf.virtual_address = (void __user *)(address & PAGE_MASK); |
2465 | vmf.pgoff = pgoff; | |
2466 | vmf.flags = flags; | |
2467 | vmf.page = NULL; | |
1da177e4 | 2468 | |
3c18ddd1 NP |
2469 | ret = vma->vm_ops->fault(vma, &vmf); |
2470 | if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) | |
2471 | return ret; | |
1da177e4 | 2472 | |
d00806b1 | 2473 | /* |
d0217ac0 | 2474 | * For consistency in subsequent calls, make the faulted page always |
d00806b1 NP |
2475 | * locked. |
2476 | */ | |
83c54070 | 2477 | if (unlikely(!(ret & VM_FAULT_LOCKED))) |
d0217ac0 | 2478 | lock_page(vmf.page); |
54cb8821 | 2479 | else |
d0217ac0 | 2480 | VM_BUG_ON(!PageLocked(vmf.page)); |
d00806b1 | 2481 | |
1da177e4 LT |
2482 | /* |
2483 | * Should we do an early C-O-W break? | |
2484 | */ | |
d0217ac0 | 2485 | page = vmf.page; |
54cb8821 | 2486 | if (flags & FAULT_FLAG_WRITE) { |
9637a5ef | 2487 | if (!(vma->vm_flags & VM_SHARED)) { |
54cb8821 | 2488 | anon = 1; |
d00806b1 | 2489 | if (unlikely(anon_vma_prepare(vma))) { |
d0217ac0 | 2490 | ret = VM_FAULT_OOM; |
54cb8821 | 2491 | goto out; |
d00806b1 | 2492 | } |
83c54070 NP |
2493 | page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, |
2494 | vma, address); | |
d00806b1 | 2495 | if (!page) { |
d0217ac0 | 2496 | ret = VM_FAULT_OOM; |
54cb8821 | 2497 | goto out; |
d00806b1 | 2498 | } |
5b4e655e KH |
2499 | if (mem_cgroup_charge(page, mm, GFP_KERNEL)) { |
2500 | ret = VM_FAULT_OOM; | |
2501 | page_cache_release(page); | |
2502 | goto out; | |
2503 | } | |
2504 | charged = 1; | |
b291f000 NP |
2505 | /* |
2506 | * Don't let another task, with possibly unlocked vma, | |
2507 | * keep the mlocked page. | |
2508 | */ | |
2509 | if (vma->vm_flags & VM_LOCKED) | |
2510 | clear_page_mlock(vmf.page); | |
d0217ac0 | 2511 | copy_user_highpage(page, vmf.page, address, vma); |
0ed361de | 2512 | __SetPageUptodate(page); |
9637a5ef | 2513 | } else { |
54cb8821 NP |
2514 | /* |
2515 | * If the page will be shareable, see if the backing | |
9637a5ef | 2516 | * address space wants to know that the page is about |
54cb8821 NP |
2517 | * to become writable |
2518 | */ | |
69676147 MF |
2519 | if (vma->vm_ops->page_mkwrite) { |
2520 | unlock_page(page); | |
2521 | if (vma->vm_ops->page_mkwrite(vma, page) < 0) { | |
d0217ac0 NP |
2522 | ret = VM_FAULT_SIGBUS; |
2523 | anon = 1; /* no anon but release vmf.page */ | |
69676147 MF |
2524 | goto out_unlocked; |
2525 | } | |
2526 | lock_page(page); | |
d0217ac0 NP |
2527 | /* |
2528 | * XXX: this is not quite right (racy vs | |
2529 | * invalidate) to unlock and relock the page | |
2530 | * like this, however a better fix requires | |
2531 | * reworking page_mkwrite locking API, which | |
2532 | * is better done later. | |
2533 | */ | |
2534 | if (!page->mapping) { | |
83c54070 | 2535 | ret = 0; |
d0217ac0 NP |
2536 | anon = 1; /* no anon but release vmf.page */ |
2537 | goto out; | |
2538 | } | |
a200ee18 | 2539 | page_mkwrite = 1; |
9637a5ef DH |
2540 | } |
2541 | } | |
54cb8821 | 2542 | |
1da177e4 LT |
2543 | } |
2544 | ||
8f4e2101 | 2545 | page_table = pte_offset_map_lock(mm, pmd, address, &ptl); |
1da177e4 LT |
2546 | |
2547 | /* | |
2548 | * This silly early PAGE_DIRTY setting removes a race | |
2549 | * due to the bad i386 page protection. But it's valid | |
2550 | * for other architectures too. | |
2551 | * | |
2552 | * Note that if write_access is true, we either now have | |
2553 | * an exclusive copy of the page, or this is a shared mapping, | |
2554 | * so we can make it writable and dirty to avoid having to | |
2555 | * handle that later. | |
2556 | */ | |
2557 | /* Only go through if we didn't race with anybody else... */ | |
54cb8821 | 2558 | if (likely(pte_same(*page_table, orig_pte))) { |
d00806b1 NP |
2559 | flush_icache_page(vma, page); |
2560 | entry = mk_pte(page, vma->vm_page_prot); | |
54cb8821 | 2561 | if (flags & FAULT_FLAG_WRITE) |
1da177e4 | 2562 | entry = maybe_mkwrite(pte_mkdirty(entry), vma); |
1da177e4 | 2563 | if (anon) { |
64d6519d | 2564 | inc_mm_counter(mm, anon_rss); |
b2e18538 | 2565 | SetPageSwapBacked(page); |
64d6519d LS |
2566 | lru_cache_add_active_or_unevictable(page, vma); |
2567 | page_add_new_anon_rmap(page, vma, address); | |
f57e88a8 | 2568 | } else { |
4294621f | 2569 | inc_mm_counter(mm, file_rss); |
d00806b1 | 2570 | page_add_file_rmap(page); |
54cb8821 | 2571 | if (flags & FAULT_FLAG_WRITE) { |
d00806b1 | 2572 | dirty_page = page; |
d08b3851 PZ |
2573 | get_page(dirty_page); |
2574 | } | |
4294621f | 2575 | } |
64d6519d LS |
2576 | //TODO: is this safe? do_anonymous_page() does it this way. |
2577 | set_pte_at(mm, address, page_table, entry); | |
d00806b1 NP |
2578 | |
2579 | /* no need to invalidate: a not-present page won't be cached */ | |
2580 | update_mmu_cache(vma, address, entry); | |
1da177e4 | 2581 | } else { |
5b4e655e KH |
2582 | if (charged) |
2583 | mem_cgroup_uncharge_page(page); | |
d00806b1 NP |
2584 | if (anon) |
2585 | page_cache_release(page); | |
2586 | else | |
54cb8821 | 2587 | anon = 1; /* no anon but release faulted_page */ |
1da177e4 LT |
2588 | } |
2589 | ||
8f4e2101 | 2590 | pte_unmap_unlock(page_table, ptl); |
d00806b1 NP |
2591 | |
2592 | out: | |
d0217ac0 | 2593 | unlock_page(vmf.page); |
69676147 | 2594 | out_unlocked: |
d00806b1 | 2595 | if (anon) |
d0217ac0 | 2596 | page_cache_release(vmf.page); |
d00806b1 | 2597 | else if (dirty_page) { |
8f7b3d15 AS |
2598 | if (vma->vm_file) |
2599 | file_update_time(vma->vm_file); | |
2600 | ||
a200ee18 | 2601 | set_page_dirty_balance(dirty_page, page_mkwrite); |
d08b3851 PZ |
2602 | put_page(dirty_page); |
2603 | } | |
d00806b1 | 2604 | |
83c54070 | 2605 | return ret; |
54cb8821 | 2606 | } |
d00806b1 | 2607 | |
54cb8821 NP |
2608 | static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
2609 | unsigned long address, pte_t *page_table, pmd_t *pmd, | |
2610 | int write_access, pte_t orig_pte) | |
2611 | { | |
2612 | pgoff_t pgoff = (((address & PAGE_MASK) | |
0da7e01f | 2613 | - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; |
54cb8821 NP |
2614 | unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0); |
2615 | ||
16abfa08 HD |
2616 | pte_unmap(page_table); |
2617 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); | |
54cb8821 NP |
2618 | } |
2619 | ||
1da177e4 LT |
2620 | /* |
2621 | * Fault of a previously existing named mapping. Repopulate the pte | |
2622 | * from the encoded file_pte if possible. This enables swappable | |
2623 | * nonlinear vmas. | |
8f4e2101 HD |
2624 | * |
2625 | * We enter with non-exclusive mmap_sem (to exclude vma changes, | |
2626 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2627 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 | 2628 | */ |
d0217ac0 | 2629 | static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
65500d23 HD |
2630 | unsigned long address, pte_t *page_table, pmd_t *pmd, |
2631 | int write_access, pte_t orig_pte) | |
1da177e4 | 2632 | { |
d0217ac0 NP |
2633 | unsigned int flags = FAULT_FLAG_NONLINEAR | |
2634 | (write_access ? FAULT_FLAG_WRITE : 0); | |
65500d23 | 2635 | pgoff_t pgoff; |
1da177e4 | 2636 | |
4c21e2f2 | 2637 | if (!pte_unmap_same(mm, pmd, page_table, orig_pte)) |
83c54070 | 2638 | return 0; |
1da177e4 | 2639 | |
d0217ac0 NP |
2640 | if (unlikely(!(vma->vm_flags & VM_NONLINEAR) || |
2641 | !(vma->vm_flags & VM_CAN_NONLINEAR))) { | |
65500d23 HD |
2642 | /* |
2643 | * Page table corrupted: show pte and kill process. | |
2644 | */ | |
b5810039 | 2645 | print_bad_pte(vma, orig_pte, address); |
65500d23 HD |
2646 | return VM_FAULT_OOM; |
2647 | } | |
65500d23 HD |
2648 | |
2649 | pgoff = pte_to_pgoff(orig_pte); | |
16abfa08 | 2650 | return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte); |
1da177e4 LT |
2651 | } |
2652 | ||
2653 | /* | |
2654 | * These routines also need to handle stuff like marking pages dirty | |
2655 | * and/or accessed for architectures that don't do it in hardware (most | |
2656 | * RISC architectures). The early dirtying is also good on the i386. | |
2657 | * | |
2658 | * There is also a hook called "update_mmu_cache()" that architectures | |
2659 | * with external mmu caches can use to update those (ie the Sparc or | |
2660 | * PowerPC hashed page tables that act as extended TLBs). | |
2661 | * | |
c74df32c HD |
2662 | * We enter with non-exclusive mmap_sem (to exclude vma changes, |
2663 | * but allow concurrent faults), and pte mapped but not yet locked. | |
2664 | * We return with mmap_sem still held, but pte unmapped and unlocked. | |
1da177e4 LT |
2665 | */ |
2666 | static inline int handle_pte_fault(struct mm_struct *mm, | |
65500d23 HD |
2667 | struct vm_area_struct *vma, unsigned long address, |
2668 | pte_t *pte, pmd_t *pmd, int write_access) | |
1da177e4 LT |
2669 | { |
2670 | pte_t entry; | |
8f4e2101 | 2671 | spinlock_t *ptl; |
1da177e4 | 2672 | |
8dab5241 | 2673 | entry = *pte; |
1da177e4 | 2674 | if (!pte_present(entry)) { |
65500d23 | 2675 | if (pte_none(entry)) { |
f4b81804 | 2676 | if (vma->vm_ops) { |
3c18ddd1 | 2677 | if (likely(vma->vm_ops->fault)) |
54cb8821 NP |
2678 | return do_linear_fault(mm, vma, address, |
2679 | pte, pmd, write_access, entry); | |
f4b81804 JS |
2680 | } |
2681 | return do_anonymous_page(mm, vma, address, | |
2682 | pte, pmd, write_access); | |
65500d23 | 2683 | } |
1da177e4 | 2684 | if (pte_file(entry)) |
d0217ac0 | 2685 | return do_nonlinear_fault(mm, vma, address, |
65500d23 HD |
2686 | pte, pmd, write_access, entry); |
2687 | return do_swap_page(mm, vma, address, | |
2688 | pte, pmd, write_access, entry); | |
1da177e4 LT |
2689 | } |
2690 | ||
4c21e2f2 | 2691 | ptl = pte_lockptr(mm, pmd); |
8f4e2101 HD |
2692 | spin_lock(ptl); |
2693 | if (unlikely(!pte_same(*pte, entry))) | |
2694 | goto unlock; | |
1da177e4 LT |
2695 | if (write_access) { |
2696 | if (!pte_write(entry)) | |
8f4e2101 HD |
2697 | return do_wp_page(mm, vma, address, |
2698 | pte, pmd, ptl, entry); | |
1da177e4 LT |
2699 | entry = pte_mkdirty(entry); |
2700 | } | |
2701 | entry = pte_mkyoung(entry); | |
8dab5241 | 2702 | if (ptep_set_access_flags(vma, address, pte, entry, write_access)) { |
1a44e149 | 2703 | update_mmu_cache(vma, address, entry); |
1a44e149 AA |
2704 | } else { |
2705 | /* | |
2706 | * This is needed only for protection faults but the arch code | |
2707 | * is not yet telling us if this is a protection fault or not. | |
2708 | * This still avoids useless tlb flushes for .text page faults | |
2709 | * with threads. | |
2710 | */ | |
2711 | if (write_access) | |
2712 | flush_tlb_page(vma, address); | |
2713 | } | |
8f4e2101 HD |
2714 | unlock: |
2715 | pte_unmap_unlock(pte, ptl); | |
83c54070 | 2716 | return 0; |
1da177e4 LT |
2717 | } |
2718 | ||
2719 | /* | |
2720 | * By the time we get here, we already hold the mm semaphore | |
2721 | */ | |
83c54070 | 2722 | int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
1da177e4 LT |
2723 | unsigned long address, int write_access) |
2724 | { | |
2725 | pgd_t *pgd; | |
2726 | pud_t *pud; | |
2727 | pmd_t *pmd; | |
2728 | pte_t *pte; | |
2729 | ||
2730 | __set_current_state(TASK_RUNNING); | |
2731 | ||
f8891e5e | 2732 | count_vm_event(PGFAULT); |
1da177e4 | 2733 | |
ac9b9c66 HD |
2734 | if (unlikely(is_vm_hugetlb_page(vma))) |
2735 | return hugetlb_fault(mm, vma, address, write_access); | |
1da177e4 | 2736 | |
1da177e4 | 2737 | pgd = pgd_offset(mm, address); |
1da177e4 LT |
2738 | pud = pud_alloc(mm, pgd, address); |
2739 | if (!pud) | |
c74df32c | 2740 | return VM_FAULT_OOM; |
1da177e4 LT |
2741 | pmd = pmd_alloc(mm, pud, address); |
2742 | if (!pmd) | |
c74df32c | 2743 | return VM_FAULT_OOM; |
1da177e4 LT |
2744 | pte = pte_alloc_map(mm, pmd, address); |
2745 | if (!pte) | |
c74df32c | 2746 | return VM_FAULT_OOM; |
1da177e4 | 2747 | |
c74df32c | 2748 | return handle_pte_fault(mm, vma, address, pte, pmd, write_access); |
1da177e4 LT |
2749 | } |
2750 | ||
2751 | #ifndef __PAGETABLE_PUD_FOLDED | |
2752 | /* | |
2753 | * Allocate page upper directory. | |
872fec16 | 2754 | * We've already handled the fast-path in-line. |
1da177e4 | 2755 | */ |
1bb3630e | 2756 | int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address) |
1da177e4 | 2757 | { |
c74df32c HD |
2758 | pud_t *new = pud_alloc_one(mm, address); |
2759 | if (!new) | |
1bb3630e | 2760 | return -ENOMEM; |
1da177e4 | 2761 | |
362a61ad NP |
2762 | smp_wmb(); /* See comment in __pte_alloc */ |
2763 | ||
872fec16 | 2764 | spin_lock(&mm->page_table_lock); |
1bb3630e | 2765 | if (pgd_present(*pgd)) /* Another has populated it */ |
5e541973 | 2766 | pud_free(mm, new); |
1bb3630e HD |
2767 | else |
2768 | pgd_populate(mm, pgd, new); | |
c74df32c | 2769 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 2770 | return 0; |
1da177e4 LT |
2771 | } |
2772 | #endif /* __PAGETABLE_PUD_FOLDED */ | |
2773 | ||
2774 | #ifndef __PAGETABLE_PMD_FOLDED | |
2775 | /* | |
2776 | * Allocate page middle directory. | |
872fec16 | 2777 | * We've already handled the fast-path in-line. |
1da177e4 | 2778 | */ |
1bb3630e | 2779 | int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address) |
1da177e4 | 2780 | { |
c74df32c HD |
2781 | pmd_t *new = pmd_alloc_one(mm, address); |
2782 | if (!new) | |
1bb3630e | 2783 | return -ENOMEM; |
1da177e4 | 2784 | |
362a61ad NP |
2785 | smp_wmb(); /* See comment in __pte_alloc */ |
2786 | ||
872fec16 | 2787 | spin_lock(&mm->page_table_lock); |
1da177e4 | 2788 | #ifndef __ARCH_HAS_4LEVEL_HACK |
1bb3630e | 2789 | if (pud_present(*pud)) /* Another has populated it */ |
5e541973 | 2790 | pmd_free(mm, new); |
1bb3630e HD |
2791 | else |
2792 | pud_populate(mm, pud, new); | |
1da177e4 | 2793 | #else |
1bb3630e | 2794 | if (pgd_present(*pud)) /* Another has populated it */ |
5e541973 | 2795 | pmd_free(mm, new); |
1bb3630e HD |
2796 | else |
2797 | pgd_populate(mm, pud, new); | |
1da177e4 | 2798 | #endif /* __ARCH_HAS_4LEVEL_HACK */ |
c74df32c | 2799 | spin_unlock(&mm->page_table_lock); |
1bb3630e | 2800 | return 0; |
e0f39591 | 2801 | } |
1da177e4 LT |
2802 | #endif /* __PAGETABLE_PMD_FOLDED */ |
2803 | ||
2804 | int make_pages_present(unsigned long addr, unsigned long end) | |
2805 | { | |
2806 | int ret, len, write; | |
2807 | struct vm_area_struct * vma; | |
2808 | ||
2809 | vma = find_vma(current->mm, addr); | |
2810 | if (!vma) | |
a477097d | 2811 | return -ENOMEM; |
1da177e4 | 2812 | write = (vma->vm_flags & VM_WRITE) != 0; |
5bcb28b1 ES |
2813 | BUG_ON(addr >= end); |
2814 | BUG_ON(end > vma->vm_end); | |
68e116a3 | 2815 | len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE; |
1da177e4 LT |
2816 | ret = get_user_pages(current, current->mm, addr, |
2817 | len, write, 0, NULL, NULL); | |
c11d69d8 | 2818 | if (ret < 0) |
1da177e4 | 2819 | return ret; |
9978ad58 | 2820 | return ret == len ? 0 : -EFAULT; |
1da177e4 LT |
2821 | } |
2822 | ||
1da177e4 LT |
2823 | #if !defined(__HAVE_ARCH_GATE_AREA) |
2824 | ||
2825 | #if defined(AT_SYSINFO_EHDR) | |
5ce7852c | 2826 | static struct vm_area_struct gate_vma; |
1da177e4 LT |
2827 | |
2828 | static int __init gate_vma_init(void) | |
2829 | { | |
2830 | gate_vma.vm_mm = NULL; | |
2831 | gate_vma.vm_start = FIXADDR_USER_START; | |
2832 | gate_vma.vm_end = FIXADDR_USER_END; | |
b6558c4a RM |
2833 | gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC; |
2834 | gate_vma.vm_page_prot = __P101; | |
f47aef55 RM |
2835 | /* |
2836 | * Make sure the vDSO gets into every core dump. | |
2837 | * Dumping its contents makes post-mortem fully interpretable later | |
2838 | * without matching up the same kernel and hardware config to see | |
2839 | * what PC values meant. | |
2840 | */ | |
2841 | gate_vma.vm_flags |= VM_ALWAYSDUMP; | |
1da177e4 LT |
2842 | return 0; |
2843 | } | |
2844 | __initcall(gate_vma_init); | |
2845 | #endif | |
2846 | ||
2847 | struct vm_area_struct *get_gate_vma(struct task_struct *tsk) | |
2848 | { | |
2849 | #ifdef AT_SYSINFO_EHDR | |
2850 | return &gate_vma; | |
2851 | #else | |
2852 | return NULL; | |
2853 | #endif | |
2854 | } | |
2855 | ||
2856 | int in_gate_area_no_task(unsigned long addr) | |
2857 | { | |
2858 | #ifdef AT_SYSINFO_EHDR | |
2859 | if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END)) | |
2860 | return 1; | |
2861 | #endif | |
2862 | return 0; | |
2863 | } | |
2864 | ||
2865 | #endif /* __HAVE_ARCH_GATE_AREA */ | |
0ec76a11 | 2866 | |
28b2ee20 RR |
2867 | #ifdef CONFIG_HAVE_IOREMAP_PROT |
2868 | static resource_size_t follow_phys(struct vm_area_struct *vma, | |
2869 | unsigned long address, unsigned int flags, | |
2870 | unsigned long *prot) | |
2871 | { | |
2872 | pgd_t *pgd; | |
2873 | pud_t *pud; | |
2874 | pmd_t *pmd; | |
2875 | pte_t *ptep, pte; | |
2876 | spinlock_t *ptl; | |
2877 | resource_size_t phys_addr = 0; | |
2878 | struct mm_struct *mm = vma->vm_mm; | |
2879 | ||
2880 | VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP))); | |
2881 | ||
2882 | pgd = pgd_offset(mm, address); | |
2883 | if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd))) | |
2884 | goto no_page_table; | |
2885 | ||
2886 | pud = pud_offset(pgd, address); | |
2887 | if (pud_none(*pud) || unlikely(pud_bad(*pud))) | |
2888 | goto no_page_table; | |
2889 | ||
2890 | pmd = pmd_offset(pud, address); | |
2891 | if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd))) | |
2892 | goto no_page_table; | |
2893 | ||
2894 | /* We cannot handle huge page PFN maps. Luckily they don't exist. */ | |
2895 | if (pmd_huge(*pmd)) | |
2896 | goto no_page_table; | |
2897 | ||
2898 | ptep = pte_offset_map_lock(mm, pmd, address, &ptl); | |
2899 | if (!ptep) | |
2900 | goto out; | |
2901 | ||
2902 | pte = *ptep; | |
2903 | if (!pte_present(pte)) | |
2904 | goto unlock; | |
2905 | if ((flags & FOLL_WRITE) && !pte_write(pte)) | |
2906 | goto unlock; | |
2907 | phys_addr = pte_pfn(pte); | |
2908 | phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */ | |
2909 | ||
2910 | *prot = pgprot_val(pte_pgprot(pte)); | |
2911 | ||
2912 | unlock: | |
2913 | pte_unmap_unlock(ptep, ptl); | |
2914 | out: | |
2915 | return phys_addr; | |
2916 | no_page_table: | |
2917 | return 0; | |
2918 | } | |
2919 | ||
2920 | int generic_access_phys(struct vm_area_struct *vma, unsigned long addr, | |
2921 | void *buf, int len, int write) | |
2922 | { | |
2923 | resource_size_t phys_addr; | |
2924 | unsigned long prot = 0; | |
2925 | void *maddr; | |
2926 | int offset = addr & (PAGE_SIZE-1); | |
2927 | ||
2928 | if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) | |
2929 | return -EINVAL; | |
2930 | ||
2931 | phys_addr = follow_phys(vma, addr, write, &prot); | |
2932 | ||
2933 | if (!phys_addr) | |
2934 | return -EINVAL; | |
2935 | ||
2936 | maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot); | |
2937 | if (write) | |
2938 | memcpy_toio(maddr + offset, buf, len); | |
2939 | else | |
2940 | memcpy_fromio(buf, maddr + offset, len); | |
2941 | iounmap(maddr); | |
2942 | ||
2943 | return len; | |
2944 | } | |
2945 | #endif | |
2946 | ||
0ec76a11 DH |
2947 | /* |
2948 | * Access another process' address space. | |
2949 | * Source/target buffer must be kernel space, | |
2950 | * Do not walk the page table directly, use get_user_pages | |
2951 | */ | |
2952 | int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write) | |
2953 | { | |
2954 | struct mm_struct *mm; | |
2955 | struct vm_area_struct *vma; | |
0ec76a11 DH |
2956 | void *old_buf = buf; |
2957 | ||
2958 | mm = get_task_mm(tsk); | |
2959 | if (!mm) | |
2960 | return 0; | |
2961 | ||
2962 | down_read(&mm->mmap_sem); | |
183ff22b | 2963 | /* ignore errors, just check how much was successfully transferred */ |
0ec76a11 DH |
2964 | while (len) { |
2965 | int bytes, ret, offset; | |
2966 | void *maddr; | |
28b2ee20 | 2967 | struct page *page = NULL; |
0ec76a11 DH |
2968 | |
2969 | ret = get_user_pages(tsk, mm, addr, 1, | |
2970 | write, 1, &page, &vma); | |
28b2ee20 RR |
2971 | if (ret <= 0) { |
2972 | /* | |
2973 | * Check if this is a VM_IO | VM_PFNMAP VMA, which | |
2974 | * we can access using slightly different code. | |
2975 | */ | |
2976 | #ifdef CONFIG_HAVE_IOREMAP_PROT | |
2977 | vma = find_vma(mm, addr); | |
2978 | if (!vma) | |
2979 | break; | |
2980 | if (vma->vm_ops && vma->vm_ops->access) | |
2981 | ret = vma->vm_ops->access(vma, addr, buf, | |
2982 | len, write); | |
2983 | if (ret <= 0) | |
2984 | #endif | |
2985 | break; | |
2986 | bytes = ret; | |
0ec76a11 | 2987 | } else { |
28b2ee20 RR |
2988 | bytes = len; |
2989 | offset = addr & (PAGE_SIZE-1); | |
2990 | if (bytes > PAGE_SIZE-offset) | |
2991 | bytes = PAGE_SIZE-offset; | |
2992 | ||
2993 | maddr = kmap(page); | |
2994 | if (write) { | |
2995 | copy_to_user_page(vma, page, addr, | |
2996 | maddr + offset, buf, bytes); | |
2997 | set_page_dirty_lock(page); | |
2998 | } else { | |
2999 | copy_from_user_page(vma, page, addr, | |
3000 | buf, maddr + offset, bytes); | |
3001 | } | |
3002 | kunmap(page); | |
3003 | page_cache_release(page); | |
0ec76a11 | 3004 | } |
0ec76a11 DH |
3005 | len -= bytes; |
3006 | buf += bytes; | |
3007 | addr += bytes; | |
3008 | } | |
3009 | up_read(&mm->mmap_sem); | |
3010 | mmput(mm); | |
3011 | ||
3012 | return buf - old_buf; | |
3013 | } | |
03252919 AK |
3014 | |
3015 | /* | |
3016 | * Print the name of a VMA. | |
3017 | */ | |
3018 | void print_vma_addr(char *prefix, unsigned long ip) | |
3019 | { | |
3020 | struct mm_struct *mm = current->mm; | |
3021 | struct vm_area_struct *vma; | |
3022 | ||
e8bff74a IM |
3023 | /* |
3024 | * Do not print if we are in atomic | |
3025 | * contexts (in exception stacks, etc.): | |
3026 | */ | |
3027 | if (preempt_count()) | |
3028 | return; | |
3029 | ||
03252919 AK |
3030 | down_read(&mm->mmap_sem); |
3031 | vma = find_vma(mm, ip); | |
3032 | if (vma && vma->vm_file) { | |
3033 | struct file *f = vma->vm_file; | |
3034 | char *buf = (char *)__get_free_page(GFP_KERNEL); | |
3035 | if (buf) { | |
3036 | char *p, *s; | |
3037 | ||
cf28b486 | 3038 | p = d_path(&f->f_path, buf, PAGE_SIZE); |
03252919 AK |
3039 | if (IS_ERR(p)) |
3040 | p = "?"; | |
3041 | s = strrchr(p, '/'); | |
3042 | if (s) | |
3043 | p = s+1; | |
3044 | printk("%s%s[%lx+%lx]", prefix, p, | |
3045 | vma->vm_start, | |
3046 | vma->vm_end - vma->vm_start); | |
3047 | free_page((unsigned long)buf); | |
3048 | } | |
3049 | } | |
3050 | up_read(¤t->mm->mmap_sem); | |
3051 | } |