blob: e046b7e4b53092bb879f8d183d24de36b3389d83 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
50#include <linux/init.h>
51
52#include <asm/pgalloc.h>
53#include <asm/uaccess.h>
54#include <asm/tlb.h>
55#include <asm/tlbflush.h>
56#include <asm/pgtable.h>
57
58#include <linux/swapops.h>
59#include <linux/elf.h>
60
Andy Whitcroftd41dee32005-06-23 00:07:54 -070061#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070062/* use the per-pgdat data instead for discontigmem - mbligh */
63unsigned long max_mapnr;
64struct page *mem_map;
65
66EXPORT_SYMBOL(max_mapnr);
67EXPORT_SYMBOL(mem_map);
68#endif
69
70unsigned long num_physpages;
71/*
72 * A number of key systems in x86 including ioremap() rely on the assumption
73 * that high_memory defines the upper bound on direct map memory, then end
74 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
75 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
76 * and ZONE_HIGHMEM.
77 */
78void * high_memory;
79unsigned long vmalloc_earlyreserve;
80
81EXPORT_SYMBOL(num_physpages);
82EXPORT_SYMBOL(high_memory);
83EXPORT_SYMBOL(vmalloc_earlyreserve);
84
85/*
86 * If a p?d_bad entry is found while walking page tables, report
87 * the error, before resetting entry to p?d_none. Usually (but
88 * very seldom) called out from the p?d_none_or_clear_bad macros.
89 */
90
91void pgd_clear_bad(pgd_t *pgd)
92{
93 pgd_ERROR(*pgd);
94 pgd_clear(pgd);
95}
96
97void pud_clear_bad(pud_t *pud)
98{
99 pud_ERROR(*pud);
100 pud_clear(pud);
101}
102
103void pmd_clear_bad(pmd_t *pmd)
104{
105 pmd_ERROR(*pmd);
106 pmd_clear(pmd);
107}
108
109/*
110 * Note: this doesn't free the actual pages themselves. That
111 * has been handled earlier when unmapping all the memory regions.
112 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700113static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
Hugh Dickinse0da3822005-04-19 13:29:15 -0700115 struct page *page = pmd_page(*pmd);
116 pmd_clear(pmd);
117 pte_free_tlb(tlb, page);
118 dec_page_state(nr_page_table_pages);
119 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120}
121
Hugh Dickinse0da3822005-04-19 13:29:15 -0700122static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
123 unsigned long addr, unsigned long end,
124 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
126 pmd_t *pmd;
127 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700128 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
Hugh Dickinse0da3822005-04-19 13:29:15 -0700130 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 do {
133 next = pmd_addr_end(addr, end);
134 if (pmd_none_or_clear_bad(pmd))
135 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700136 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 } while (pmd++, addr = next, addr != end);
138
Hugh Dickinse0da3822005-04-19 13:29:15 -0700139 start &= PUD_MASK;
140 if (start < floor)
141 return;
142 if (ceiling) {
143 ceiling &= PUD_MASK;
144 if (!ceiling)
145 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700147 if (end - 1 > ceiling - 1)
148 return;
149
150 pmd = pmd_offset(pud, start);
151 pud_clear(pud);
152 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
154
Hugh Dickinse0da3822005-04-19 13:29:15 -0700155static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
156 unsigned long addr, unsigned long end,
157 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158{
159 pud_t *pud;
160 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700161 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Hugh Dickinse0da3822005-04-19 13:29:15 -0700163 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 do {
166 next = pud_addr_end(addr, end);
167 if (pud_none_or_clear_bad(pud))
168 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700169 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 } while (pud++, addr = next, addr != end);
171
Hugh Dickinse0da3822005-04-19 13:29:15 -0700172 start &= PGDIR_MASK;
173 if (start < floor)
174 return;
175 if (ceiling) {
176 ceiling &= PGDIR_MASK;
177 if (!ceiling)
178 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700180 if (end - 1 > ceiling - 1)
181 return;
182
183 pud = pud_offset(pgd, start);
184 pgd_clear(pgd);
185 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186}
187
188/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700189 * This function frees user-level page tables of a process.
190 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 * Must be called with pagetable lock held.
192 */
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700193void free_pgd_range(struct mmu_gather **tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700194 unsigned long addr, unsigned long end,
195 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196{
197 pgd_t *pgd;
198 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700199 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Hugh Dickinse0da3822005-04-19 13:29:15 -0700201 /*
202 * The next few lines have given us lots of grief...
203 *
204 * Why are we testing PMD* at this top level? Because often
205 * there will be no work to do at all, and we'd prefer not to
206 * go all the way down to the bottom just to discover that.
207 *
208 * Why all these "- 1"s? Because 0 represents both the bottom
209 * of the address space and the top of it (using -1 for the
210 * top wouldn't help much: the masks would do the wrong thing).
211 * The rule is that addr 0 and floor 0 refer to the bottom of
212 * the address space, but end 0 and ceiling 0 refer to the top
213 * Comparisons need to use "end - 1" and "ceiling - 1" (though
214 * that end 0 case should be mythical).
215 *
216 * Wherever addr is brought up or ceiling brought down, we must
217 * be careful to reject "the opposite 0" before it confuses the
218 * subsequent tests. But what about where end is brought down
219 * by PMD_SIZE below? no, end can't go down to 0 there.
220 *
221 * Whereas we round start (addr) and ceiling down, by different
222 * masks at different levels, in order to test whether a table
223 * now has no other vmas using it, so can be freed, we don't
224 * bother to round floor or end up - the tests don't need that.
225 */
226
227 addr &= PMD_MASK;
228 if (addr < floor) {
229 addr += PMD_SIZE;
230 if (!addr)
231 return;
232 }
233 if (ceiling) {
234 ceiling &= PMD_MASK;
235 if (!ceiling)
236 return;
237 }
238 if (end - 1 > ceiling - 1)
239 end -= PMD_SIZE;
240 if (addr > end - 1)
241 return;
242
243 start = addr;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700244 pgd = pgd_offset((*tlb)->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 do {
246 next = pgd_addr_end(addr, end);
247 if (pgd_none_or_clear_bad(pgd))
248 continue;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700249 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700251
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700252 if (!tlb_is_full_mm(*tlb))
253 flush_tlb_pgtables((*tlb)->mm, start, end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700254}
255
256void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700257 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700258{
259 while (vma) {
260 struct vm_area_struct *next = vma->vm_next;
261 unsigned long addr = vma->vm_start;
262
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700263 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
264 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700265 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700266 } else {
267 /*
268 * Optimization: gather nearby vmas into one call down
269 */
270 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
271 && !is_hugepage_only_range(vma->vm_mm, next->vm_start,
272 HPAGE_SIZE)) {
273 vma = next;
274 next = vma->vm_next;
275 }
276 free_pgd_range(tlb, addr, vma->vm_end,
277 floor, next? next->vm_start: ceiling);
278 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700279 vma = next;
280 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281}
282
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700283pte_t fastcall *pte_alloc_map(struct mm_struct *mm, pmd_t *pmd,
284 unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700285{
286 if (!pmd_present(*pmd)) {
287 struct page *new;
288
289 spin_unlock(&mm->page_table_lock);
290 new = pte_alloc_one(mm, address);
291 spin_lock(&mm->page_table_lock);
292 if (!new)
293 return NULL;
294 /*
295 * Because we dropped the lock, we should re-check the
296 * entry, as somebody else could have populated it..
297 */
298 if (pmd_present(*pmd)) {
299 pte_free(new);
300 goto out;
301 }
302 mm->nr_ptes++;
303 inc_page_state(nr_page_table_pages);
304 pmd_populate(mm, pmd, new);
305 }
306out:
307 return pte_offset_map(pmd, address);
308}
309
310pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
311{
312 if (!pmd_present(*pmd)) {
313 pte_t *new;
314
315 spin_unlock(&mm->page_table_lock);
316 new = pte_alloc_one_kernel(mm, address);
317 spin_lock(&mm->page_table_lock);
318 if (!new)
319 return NULL;
320
321 /*
322 * Because we dropped the lock, we should re-check the
323 * entry, as somebody else could have populated it..
324 */
325 if (pmd_present(*pmd)) {
326 pte_free_kernel(new);
327 goto out;
328 }
329 pmd_populate_kernel(mm, pmd, new);
330 }
331out:
332 return pte_offset_kernel(pmd, address);
333}
334
335/*
336 * copy one vm_area from one task to the other. Assumes the page tables
337 * already present in the new task to be cleared in the whole range
338 * covered by this vma.
339 *
340 * dst->page_table_lock is held on entry and exit,
341 * but may be dropped within p[mg]d_alloc() and pte_alloc_map().
342 */
343
344static inline void
345copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
346 pte_t *dst_pte, pte_t *src_pte, unsigned long vm_flags,
347 unsigned long addr)
348{
349 pte_t pte = *src_pte;
350 struct page *page;
351 unsigned long pfn;
352
353 /* pte contains position in swap or file, so copy. */
354 if (unlikely(!pte_present(pte))) {
355 if (!pte_file(pte)) {
356 swap_duplicate(pte_to_swp_entry(pte));
357 /* make sure dst_mm is on swapoff's mmlist. */
358 if (unlikely(list_empty(&dst_mm->mmlist))) {
359 spin_lock(&mmlist_lock);
360 list_add(&dst_mm->mmlist, &src_mm->mmlist);
361 spin_unlock(&mmlist_lock);
362 }
363 }
364 set_pte_at(dst_mm, addr, dst_pte, pte);
365 return;
366 }
367
368 pfn = pte_pfn(pte);
369 /* the pte points outside of valid memory, the
370 * mapping is assumed to be good, meaningful
371 * and not mapped via rmap - duplicate the
372 * mapping as is.
373 */
374 page = NULL;
375 if (pfn_valid(pfn))
376 page = pfn_to_page(pfn);
377
378 if (!page || PageReserved(page)) {
379 set_pte_at(dst_mm, addr, dst_pte, pte);
380 return;
381 }
382
383 /*
384 * If it's a COW mapping, write protect it both
385 * in the parent and the child
386 */
387 if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) {
388 ptep_set_wrprotect(src_mm, addr, src_pte);
389 pte = *src_pte;
390 }
391
392 /*
393 * If it's a shared mapping, mark it clean in
394 * the child
395 */
396 if (vm_flags & VM_SHARED)
397 pte = pte_mkclean(pte);
398 pte = pte_mkold(pte);
399 get_page(page);
400 inc_mm_counter(dst_mm, rss);
401 if (PageAnon(page))
402 inc_mm_counter(dst_mm, anon_rss);
403 set_pte_at(dst_mm, addr, dst_pte, pte);
404 page_dup_rmap(page);
405}
406
407static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
408 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
409 unsigned long addr, unsigned long end)
410{
411 pte_t *src_pte, *dst_pte;
412 unsigned long vm_flags = vma->vm_flags;
413 int progress;
414
415again:
416 dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr);
417 if (!dst_pte)
418 return -ENOMEM;
419 src_pte = pte_offset_map_nested(src_pmd, addr);
420
421 progress = 0;
422 spin_lock(&src_mm->page_table_lock);
423 do {
424 /*
425 * We are holding two locks at this point - either of them
426 * could generate latencies in another task on another CPU.
427 */
428 if (progress >= 32 && (need_resched() ||
429 need_lockbreak(&src_mm->page_table_lock) ||
430 need_lockbreak(&dst_mm->page_table_lock)))
431 break;
432 if (pte_none(*src_pte)) {
433 progress++;
434 continue;
435 }
436 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vm_flags, addr);
437 progress += 8;
438 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
439 spin_unlock(&src_mm->page_table_lock);
440
441 pte_unmap_nested(src_pte - 1);
442 pte_unmap(dst_pte - 1);
443 cond_resched_lock(&dst_mm->page_table_lock);
444 if (addr != end)
445 goto again;
446 return 0;
447}
448
449static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
450 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
451 unsigned long addr, unsigned long end)
452{
453 pmd_t *src_pmd, *dst_pmd;
454 unsigned long next;
455
456 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
457 if (!dst_pmd)
458 return -ENOMEM;
459 src_pmd = pmd_offset(src_pud, addr);
460 do {
461 next = pmd_addr_end(addr, end);
462 if (pmd_none_or_clear_bad(src_pmd))
463 continue;
464 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
465 vma, addr, next))
466 return -ENOMEM;
467 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
468 return 0;
469}
470
471static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
472 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
473 unsigned long addr, unsigned long end)
474{
475 pud_t *src_pud, *dst_pud;
476 unsigned long next;
477
478 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
479 if (!dst_pud)
480 return -ENOMEM;
481 src_pud = pud_offset(src_pgd, addr);
482 do {
483 next = pud_addr_end(addr, end);
484 if (pud_none_or_clear_bad(src_pud))
485 continue;
486 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
487 vma, addr, next))
488 return -ENOMEM;
489 } while (dst_pud++, src_pud++, addr = next, addr != end);
490 return 0;
491}
492
493int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
494 struct vm_area_struct *vma)
495{
496 pgd_t *src_pgd, *dst_pgd;
497 unsigned long next;
498 unsigned long addr = vma->vm_start;
499 unsigned long end = vma->vm_end;
500
501 if (is_vm_hugetlb_page(vma))
502 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
503
504 dst_pgd = pgd_offset(dst_mm, addr);
505 src_pgd = pgd_offset(src_mm, addr);
506 do {
507 next = pgd_addr_end(addr, end);
508 if (pgd_none_or_clear_bad(src_pgd))
509 continue;
510 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
511 vma, addr, next))
512 return -ENOMEM;
513 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
514 return 0;
515}
516
517static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
518 unsigned long addr, unsigned long end,
519 struct zap_details *details)
520{
521 pte_t *pte;
522
523 pte = pte_offset_map(pmd, addr);
524 do {
525 pte_t ptent = *pte;
526 if (pte_none(ptent))
527 continue;
528 if (pte_present(ptent)) {
529 struct page *page = NULL;
530 unsigned long pfn = pte_pfn(ptent);
531 if (pfn_valid(pfn)) {
532 page = pfn_to_page(pfn);
533 if (PageReserved(page))
534 page = NULL;
535 }
536 if (unlikely(details) && page) {
537 /*
538 * unmap_shared_mapping_pages() wants to
539 * invalidate cache without truncating:
540 * unmap shared but keep private pages.
541 */
542 if (details->check_mapping &&
543 details->check_mapping != page->mapping)
544 continue;
545 /*
546 * Each page->index must be checked when
547 * invalidating or truncating nonlinear.
548 */
549 if (details->nonlinear_vma &&
550 (page->index < details->first_index ||
551 page->index > details->last_index))
552 continue;
553 }
554 ptent = ptep_get_and_clear(tlb->mm, addr, pte);
555 tlb_remove_tlb_entry(tlb, pte, addr);
556 if (unlikely(!page))
557 continue;
558 if (unlikely(details) && details->nonlinear_vma
559 && linear_page_index(details->nonlinear_vma,
560 addr) != page->index)
561 set_pte_at(tlb->mm, addr, pte,
562 pgoff_to_pte(page->index));
563 if (pte_dirty(ptent))
564 set_page_dirty(page);
565 if (PageAnon(page))
566 dec_mm_counter(tlb->mm, anon_rss);
567 else if (pte_young(ptent))
568 mark_page_accessed(page);
569 tlb->freed++;
570 page_remove_rmap(page);
571 tlb_remove_page(tlb, page);
572 continue;
573 }
574 /*
575 * If details->check_mapping, we leave swap entries;
576 * if details->nonlinear_vma, we leave file entries.
577 */
578 if (unlikely(details))
579 continue;
580 if (!pte_file(ptent))
581 free_swap_and_cache(pte_to_swp_entry(ptent));
582 pte_clear(tlb->mm, addr, pte);
583 } while (pte++, addr += PAGE_SIZE, addr != end);
584 pte_unmap(pte - 1);
585}
586
587static inline void zap_pmd_range(struct mmu_gather *tlb, pud_t *pud,
588 unsigned long addr, unsigned long end,
589 struct zap_details *details)
590{
591 pmd_t *pmd;
592 unsigned long next;
593
594 pmd = pmd_offset(pud, addr);
595 do {
596 next = pmd_addr_end(addr, end);
597 if (pmd_none_or_clear_bad(pmd))
598 continue;
599 zap_pte_range(tlb, pmd, addr, next, details);
600 } while (pmd++, addr = next, addr != end);
601}
602
603static inline void zap_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
604 unsigned long addr, unsigned long end,
605 struct zap_details *details)
606{
607 pud_t *pud;
608 unsigned long next;
609
610 pud = pud_offset(pgd, addr);
611 do {
612 next = pud_addr_end(addr, end);
613 if (pud_none_or_clear_bad(pud))
614 continue;
615 zap_pmd_range(tlb, pud, addr, next, details);
616 } while (pud++, addr = next, addr != end);
617}
618
619static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
620 unsigned long addr, unsigned long end,
621 struct zap_details *details)
622{
623 pgd_t *pgd;
624 unsigned long next;
625
626 if (details && !details->check_mapping && !details->nonlinear_vma)
627 details = NULL;
628
629 BUG_ON(addr >= end);
630 tlb_start_vma(tlb, vma);
631 pgd = pgd_offset(vma->vm_mm, addr);
632 do {
633 next = pgd_addr_end(addr, end);
634 if (pgd_none_or_clear_bad(pgd))
635 continue;
636 zap_pud_range(tlb, pgd, addr, next, details);
637 } while (pgd++, addr = next, addr != end);
638 tlb_end_vma(tlb, vma);
639}
640
641#ifdef CONFIG_PREEMPT
642# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
643#else
644/* No preempt: go for improved straight-line efficiency */
645# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
646#endif
647
648/**
649 * unmap_vmas - unmap a range of memory covered by a list of vma's
650 * @tlbp: address of the caller's struct mmu_gather
651 * @mm: the controlling mm_struct
652 * @vma: the starting vma
653 * @start_addr: virtual address at which to start unmapping
654 * @end_addr: virtual address at which to end unmapping
655 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
656 * @details: details of nonlinear truncation or shared cache invalidation
657 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700658 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 *
660 * Unmap all pages in the vma list. Called under page_table_lock.
661 *
662 * We aim to not hold page_table_lock for too long (for scheduling latency
663 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
664 * return the ending mmu_gather to the caller.
665 *
666 * Only addresses between `start' and `end' will be unmapped.
667 *
668 * The VMA list must be sorted in ascending virtual address order.
669 *
670 * unmap_vmas() assumes that the caller will flush the whole unmapped address
671 * range after unmap_vmas() returns. So the only responsibility here is to
672 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
673 * drops the lock and schedules.
674 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700675unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 struct vm_area_struct *vma, unsigned long start_addr,
677 unsigned long end_addr, unsigned long *nr_accounted,
678 struct zap_details *details)
679{
680 unsigned long zap_bytes = ZAP_BLOCK_SIZE;
681 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
682 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700683 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
685 int fullmm = tlb_is_full_mm(*tlbp);
686
687 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 unsigned long end;
689
690 start = max(vma->vm_start, start_addr);
691 if (start >= vma->vm_end)
692 continue;
693 end = min(vma->vm_end, end_addr);
694 if (end <= vma->vm_start)
695 continue;
696
697 if (vma->vm_flags & VM_ACCOUNT)
698 *nr_accounted += (end - start) >> PAGE_SHIFT;
699
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 while (start != end) {
701 unsigned long block;
702
703 if (!tlb_start_valid) {
704 tlb_start = start;
705 tlb_start_valid = 1;
706 }
707
708 if (is_vm_hugetlb_page(vma)) {
709 block = end - start;
710 unmap_hugepage_range(vma, start, end);
711 } else {
712 block = min(zap_bytes, end - start);
713 unmap_page_range(*tlbp, vma, start,
714 start + block, details);
715 }
716
717 start += block;
718 zap_bytes -= block;
719 if ((long)zap_bytes > 0)
720 continue;
721
722 tlb_finish_mmu(*tlbp, tlb_start, start);
723
724 if (need_resched() ||
725 need_lockbreak(&mm->page_table_lock) ||
726 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
727 if (i_mmap_lock) {
728 /* must reset count of rss freed */
729 *tlbp = tlb_gather_mmu(mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 goto out;
731 }
732 spin_unlock(&mm->page_table_lock);
733 cond_resched();
734 spin_lock(&mm->page_table_lock);
735 }
736
737 *tlbp = tlb_gather_mmu(mm, fullmm);
738 tlb_start_valid = 0;
739 zap_bytes = ZAP_BLOCK_SIZE;
740 }
741 }
742out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700743 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744}
745
746/**
747 * zap_page_range - remove user pages in a given range
748 * @vma: vm_area_struct holding the applicable pages
749 * @address: starting address of pages to zap
750 * @size: number of bytes to zap
751 * @details: details of nonlinear truncation or shared cache invalidation
752 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700753unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 unsigned long size, struct zap_details *details)
755{
756 struct mm_struct *mm = vma->vm_mm;
757 struct mmu_gather *tlb;
758 unsigned long end = address + size;
759 unsigned long nr_accounted = 0;
760
761 if (is_vm_hugetlb_page(vma)) {
762 zap_hugepage_range(vma, address, size);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700763 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 }
765
766 lru_add_drain();
767 spin_lock(&mm->page_table_lock);
768 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700769 end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 tlb_finish_mmu(tlb, address, end);
771 spin_unlock(&mm->page_table_lock);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700772 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773}
774
775/*
776 * Do a quick page-table lookup for a single page.
777 * mm->page_table_lock must be held.
778 */
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700779static struct page *__follow_page(struct mm_struct *mm, unsigned long address,
780 int read, int write, int accessed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781{
782 pgd_t *pgd;
783 pud_t *pud;
784 pmd_t *pmd;
785 pte_t *ptep, pte;
786 unsigned long pfn;
787 struct page *page;
788
789 page = follow_huge_addr(mm, address, write);
790 if (! IS_ERR(page))
791 return page;
792
793 pgd = pgd_offset(mm, address);
794 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
795 goto out;
796
797 pud = pud_offset(pgd, address);
798 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
799 goto out;
800
801 pmd = pmd_offset(pud, address);
802 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
803 goto out;
804 if (pmd_huge(*pmd))
805 return follow_huge_pmd(mm, address, pmd, write);
806
807 ptep = pte_offset_map(pmd, address);
808 if (!ptep)
809 goto out;
810
811 pte = *ptep;
812 pte_unmap(ptep);
813 if (pte_present(pte)) {
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000814 if (write && !pte_write(pte))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 goto out;
816 if (read && !pte_read(pte))
817 goto out;
818 pfn = pte_pfn(pte);
819 if (pfn_valid(pfn)) {
820 page = pfn_to_page(pfn);
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000821 if (accessed) {
822 if (write && !pte_dirty(pte) &&!PageDirty(page))
823 set_page_dirty(page);
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700824 mark_page_accessed(page);
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000825 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 return page;
827 }
828 }
829
830out:
831 return NULL;
832}
833
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700834inline struct page *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835follow_page(struct mm_struct *mm, unsigned long address, int write)
836{
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700837 return __follow_page(mm, address, 0, write, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838}
839
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700840/*
841 * check_user_page_readable() can be called frm niterrupt context by oprofile,
842 * so we need to avoid taking any non-irq-safe locks
843 */
844int check_user_page_readable(struct mm_struct *mm, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845{
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700846 return __follow_page(mm, address, 1, 0, 0) != NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848EXPORT_SYMBOL(check_user_page_readable);
849
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850static inline int
851untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
852 unsigned long address)
853{
854 pgd_t *pgd;
855 pud_t *pud;
856 pmd_t *pmd;
857
858 /* Check if the vma is for an anonymous mapping. */
859 if (vma->vm_ops && vma->vm_ops->nopage)
860 return 0;
861
862 /* Check if page directory entry exists. */
863 pgd = pgd_offset(mm, address);
864 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
865 return 1;
866
867 pud = pud_offset(pgd, address);
868 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
869 return 1;
870
871 /* Check if page middle directory entry exists. */
872 pmd = pmd_offset(pud, address);
873 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
874 return 1;
875
876 /* There is a pte slot for 'address' in 'mm'. */
877 return 0;
878}
879
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
881 unsigned long start, int len, int write, int force,
882 struct page **pages, struct vm_area_struct **vmas)
883{
884 int i;
885 unsigned int flags;
886
887 /*
888 * Require read or write permissions.
889 * If 'force' is set, we only require the "MAY" flags.
890 */
891 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
892 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
893 i = 0;
894
895 do {
896 struct vm_area_struct * vma;
897
898 vma = find_extend_vma(mm, start);
899 if (!vma && in_gate_area(tsk, start)) {
900 unsigned long pg = start & PAGE_MASK;
901 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
902 pgd_t *pgd;
903 pud_t *pud;
904 pmd_t *pmd;
905 pte_t *pte;
906 if (write) /* user gate pages are read-only */
907 return i ? : -EFAULT;
908 if (pg > TASK_SIZE)
909 pgd = pgd_offset_k(pg);
910 else
911 pgd = pgd_offset_gate(mm, pg);
912 BUG_ON(pgd_none(*pgd));
913 pud = pud_offset(pgd, pg);
914 BUG_ON(pud_none(*pud));
915 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700916 if (pmd_none(*pmd))
917 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700919 if (pte_none(*pte)) {
920 pte_unmap(pte);
921 return i ? : -EFAULT;
922 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 if (pages) {
924 pages[i] = pte_page(*pte);
925 get_page(pages[i]);
926 }
927 pte_unmap(pte);
928 if (vmas)
929 vmas[i] = gate_vma;
930 i++;
931 start += PAGE_SIZE;
932 len--;
933 continue;
934 }
935
936 if (!vma || (vma->vm_flags & VM_IO)
937 || !(flags & vma->vm_flags))
938 return i ? : -EFAULT;
939
940 if (is_vm_hugetlb_page(vma)) {
941 i = follow_hugetlb_page(mm, vma, pages, vmas,
942 &start, &len, i);
943 continue;
944 }
945 spin_lock(&mm->page_table_lock);
946 do {
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000947 int write_access = write;
Hugh Dickins08ef4722005-06-21 17:15:10 -0700948 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949
950 cond_resched_lock(&mm->page_table_lock);
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000951 while (!(page = follow_page(mm, start, write_access))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -0700952 int ret;
953
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 /*
955 * Shortcut for anonymous pages. We don't want
956 * to force the creation of pages tables for
Hugh Dickins08ef4722005-06-21 17:15:10 -0700957 * insanely big anonymously mapped areas that
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 * nobody touched so far. This is important
959 * for doing a core dump for these mappings.
960 */
Linus Torvalds4ceb5db2005-08-01 11:14:49 -0700961 if (!write && untouched_anonymous_page(mm,vma,start)) {
Hugh Dickins08ef4722005-06-21 17:15:10 -0700962 page = ZERO_PAGE(start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963 break;
964 }
965 spin_unlock(&mm->page_table_lock);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -0700966 ret = __handle_mm_fault(mm, vma, start, write_access);
967
968 /*
969 * The VM_FAULT_WRITE bit tells us that do_wp_page has
970 * broken COW when necessary, even if maybe_mkwrite
971 * decided not to set pte_write. We can thus safely do
972 * subsequent page lookups as if they were reads.
973 */
974 if (ret & VM_FAULT_WRITE)
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000975 write_access = 0;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -0700976
977 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700978 case VM_FAULT_MINOR:
979 tsk->min_flt++;
980 break;
981 case VM_FAULT_MAJOR:
982 tsk->maj_flt++;
983 break;
984 case VM_FAULT_SIGBUS:
985 return i ? i : -EFAULT;
986 case VM_FAULT_OOM:
987 return i ? i : -ENOMEM;
988 default:
989 BUG();
990 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991 spin_lock(&mm->page_table_lock);
992 }
993 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -0700994 pages[i] = page;
995 flush_dcache_page(page);
996 if (!PageReserved(page))
997 page_cache_get(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 }
999 if (vmas)
1000 vmas[i] = vma;
1001 i++;
1002 start += PAGE_SIZE;
1003 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001004 } while (len && start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 spin_unlock(&mm->page_table_lock);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001006 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 return i;
1008}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001009EXPORT_SYMBOL(get_user_pages);
1010
1011static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1012 unsigned long addr, unsigned long end, pgprot_t prot)
1013{
1014 pte_t *pte;
1015
1016 pte = pte_alloc_map(mm, pmd, addr);
1017 if (!pte)
1018 return -ENOMEM;
1019 do {
1020 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(addr), prot));
1021 BUG_ON(!pte_none(*pte));
1022 set_pte_at(mm, addr, pte, zero_pte);
1023 } while (pte++, addr += PAGE_SIZE, addr != end);
1024 pte_unmap(pte - 1);
1025 return 0;
1026}
1027
1028static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1029 unsigned long addr, unsigned long end, pgprot_t prot)
1030{
1031 pmd_t *pmd;
1032 unsigned long next;
1033
1034 pmd = pmd_alloc(mm, pud, addr);
1035 if (!pmd)
1036 return -ENOMEM;
1037 do {
1038 next = pmd_addr_end(addr, end);
1039 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1040 return -ENOMEM;
1041 } while (pmd++, addr = next, addr != end);
1042 return 0;
1043}
1044
1045static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1046 unsigned long addr, unsigned long end, pgprot_t prot)
1047{
1048 pud_t *pud;
1049 unsigned long next;
1050
1051 pud = pud_alloc(mm, pgd, addr);
1052 if (!pud)
1053 return -ENOMEM;
1054 do {
1055 next = pud_addr_end(addr, end);
1056 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1057 return -ENOMEM;
1058 } while (pud++, addr = next, addr != end);
1059 return 0;
1060}
1061
1062int zeromap_page_range(struct vm_area_struct *vma,
1063 unsigned long addr, unsigned long size, pgprot_t prot)
1064{
1065 pgd_t *pgd;
1066 unsigned long next;
1067 unsigned long end = addr + size;
1068 struct mm_struct *mm = vma->vm_mm;
1069 int err;
1070
1071 BUG_ON(addr >= end);
1072 pgd = pgd_offset(mm, addr);
1073 flush_cache_range(vma, addr, end);
1074 spin_lock(&mm->page_table_lock);
1075 do {
1076 next = pgd_addr_end(addr, end);
1077 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1078 if (err)
1079 break;
1080 } while (pgd++, addr = next, addr != end);
1081 spin_unlock(&mm->page_table_lock);
1082 return err;
1083}
1084
1085/*
1086 * maps a range of physical memory into the requested pages. the old
1087 * mappings are removed. any references to nonexistent pages results
1088 * in null mappings (currently treated as "copy-on-access")
1089 */
1090static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1091 unsigned long addr, unsigned long end,
1092 unsigned long pfn, pgprot_t prot)
1093{
1094 pte_t *pte;
1095
1096 pte = pte_alloc_map(mm, pmd, addr);
1097 if (!pte)
1098 return -ENOMEM;
1099 do {
1100 BUG_ON(!pte_none(*pte));
1101 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
1102 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
1103 pfn++;
1104 } while (pte++, addr += PAGE_SIZE, addr != end);
1105 pte_unmap(pte - 1);
1106 return 0;
1107}
1108
1109static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1110 unsigned long addr, unsigned long end,
1111 unsigned long pfn, pgprot_t prot)
1112{
1113 pmd_t *pmd;
1114 unsigned long next;
1115
1116 pfn -= addr >> PAGE_SHIFT;
1117 pmd = pmd_alloc(mm, pud, addr);
1118 if (!pmd)
1119 return -ENOMEM;
1120 do {
1121 next = pmd_addr_end(addr, end);
1122 if (remap_pte_range(mm, pmd, addr, next,
1123 pfn + (addr >> PAGE_SHIFT), prot))
1124 return -ENOMEM;
1125 } while (pmd++, addr = next, addr != end);
1126 return 0;
1127}
1128
1129static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1130 unsigned long addr, unsigned long end,
1131 unsigned long pfn, pgprot_t prot)
1132{
1133 pud_t *pud;
1134 unsigned long next;
1135
1136 pfn -= addr >> PAGE_SHIFT;
1137 pud = pud_alloc(mm, pgd, addr);
1138 if (!pud)
1139 return -ENOMEM;
1140 do {
1141 next = pud_addr_end(addr, end);
1142 if (remap_pmd_range(mm, pud, addr, next,
1143 pfn + (addr >> PAGE_SHIFT), prot))
1144 return -ENOMEM;
1145 } while (pud++, addr = next, addr != end);
1146 return 0;
1147}
1148
1149/* Note: this is only safe if the mm semaphore is held when called. */
1150int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1151 unsigned long pfn, unsigned long size, pgprot_t prot)
1152{
1153 pgd_t *pgd;
1154 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001155 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001156 struct mm_struct *mm = vma->vm_mm;
1157 int err;
1158
1159 /*
1160 * Physically remapped pages are special. Tell the
1161 * rest of the world about it:
1162 * VM_IO tells people not to look at these pages
1163 * (accesses can have side effects).
1164 * VM_RESERVED tells swapout not to try to touch
1165 * this region.
1166 */
1167 vma->vm_flags |= VM_IO | VM_RESERVED;
1168
1169 BUG_ON(addr >= end);
1170 pfn -= addr >> PAGE_SHIFT;
1171 pgd = pgd_offset(mm, addr);
1172 flush_cache_range(vma, addr, end);
1173 spin_lock(&mm->page_table_lock);
1174 do {
1175 next = pgd_addr_end(addr, end);
1176 err = remap_pud_range(mm, pgd, addr, next,
1177 pfn + (addr >> PAGE_SHIFT), prot);
1178 if (err)
1179 break;
1180 } while (pgd++, addr = next, addr != end);
1181 spin_unlock(&mm->page_table_lock);
1182 return err;
1183}
1184EXPORT_SYMBOL(remap_pfn_range);
1185
1186/*
1187 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1188 * servicing faults for write access. In the normal case, do always want
1189 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1190 * that do not have writing enabled, when used by access_process_vm.
1191 */
1192static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1193{
1194 if (likely(vma->vm_flags & VM_WRITE))
1195 pte = pte_mkwrite(pte);
1196 return pte;
1197}
1198
1199/*
1200 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
1201 */
1202static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address,
1203 pte_t *page_table)
1204{
1205 pte_t entry;
1206
1207 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)),
1208 vma);
1209 ptep_establish(vma, address, page_table, entry);
1210 update_mmu_cache(vma, address, entry);
1211 lazy_mmu_prot_update(entry);
1212}
1213
1214/*
1215 * This routine handles present pages, when users try to write
1216 * to a shared page. It is done by copying the page to a new address
1217 * and decrementing the shared-page counter for the old page.
1218 *
1219 * Goto-purists beware: the only reason for goto's here is that it results
1220 * in better assembly code.. The "default" path will see no jumps at all.
1221 *
1222 * Note that this routine assumes that the protection checks have been
1223 * done by the caller (the low-level page fault routine in most cases).
1224 * Thus we can safely just mark it writable once we've done any necessary
1225 * COW.
1226 *
1227 * We also mark the page dirty at this point even though the page will
1228 * change only once the write actually happens. This avoids a few races,
1229 * and potentially makes it more efficient.
1230 *
1231 * We hold the mm semaphore and the page_table_lock on entry and exit
1232 * with the page_table_lock released.
1233 */
1234static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
1235 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte)
1236{
1237 struct page *old_page, *new_page;
1238 unsigned long pfn = pte_pfn(pte);
1239 pte_t entry;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001240 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241
1242 if (unlikely(!pfn_valid(pfn))) {
1243 /*
1244 * This should really halt the system so it can be debugged or
1245 * at least the kernel stops what it's doing before it corrupts
1246 * data, but for the moment just pretend this is OOM.
1247 */
1248 pte_unmap(page_table);
1249 printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n",
1250 address);
1251 spin_unlock(&mm->page_table_lock);
1252 return VM_FAULT_OOM;
1253 }
1254 old_page = pfn_to_page(pfn);
1255
Hugh Dickinsd296e9c2005-06-21 17:15:11 -07001256 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 int reuse = can_share_swap_page(old_page);
1258 unlock_page(old_page);
1259 if (reuse) {
1260 flush_cache_page(vma, address, pfn);
1261 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)),
1262 vma);
1263 ptep_set_access_flags(vma, address, page_table, entry, 1);
1264 update_mmu_cache(vma, address, entry);
1265 lazy_mmu_prot_update(entry);
1266 pte_unmap(page_table);
1267 spin_unlock(&mm->page_table_lock);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001268 return VM_FAULT_MINOR|VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 }
1270 }
1271 pte_unmap(page_table);
1272
1273 /*
1274 * Ok, we need to copy. Oh, well..
1275 */
1276 if (!PageReserved(old_page))
1277 page_cache_get(old_page);
1278 spin_unlock(&mm->page_table_lock);
1279
1280 if (unlikely(anon_vma_prepare(vma)))
1281 goto no_new_page;
1282 if (old_page == ZERO_PAGE(address)) {
1283 new_page = alloc_zeroed_user_highpage(vma, address);
1284 if (!new_page)
1285 goto no_new_page;
1286 } else {
1287 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1288 if (!new_page)
1289 goto no_new_page;
1290 copy_user_highpage(new_page, old_page, address);
1291 }
1292 /*
1293 * Re-check the pte - we dropped the lock
1294 */
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001295 ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 spin_lock(&mm->page_table_lock);
1297 page_table = pte_offset_map(pmd, address);
1298 if (likely(pte_same(*page_table, pte))) {
1299 if (PageAnon(old_page))
1300 dec_mm_counter(mm, anon_rss);
1301 if (PageReserved(old_page))
1302 inc_mm_counter(mm, rss);
1303 else
1304 page_remove_rmap(old_page);
1305 flush_cache_page(vma, address, pfn);
1306 break_cow(vma, new_page, address, page_table);
1307 lru_cache_add_active(new_page);
1308 page_add_anon_rmap(new_page, vma, address);
1309
1310 /* Free the old page.. */
1311 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001312 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001313 }
1314 pte_unmap(page_table);
1315 page_cache_release(new_page);
1316 page_cache_release(old_page);
1317 spin_unlock(&mm->page_table_lock);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001318 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001319
1320no_new_page:
1321 page_cache_release(old_page);
1322 return VM_FAULT_OOM;
1323}
1324
1325/*
1326 * Helper functions for unmap_mapping_range().
1327 *
1328 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1329 *
1330 * We have to restart searching the prio_tree whenever we drop the lock,
1331 * since the iterator is only valid while the lock is held, and anyway
1332 * a later vma might be split and reinserted earlier while lock dropped.
1333 *
1334 * The list of nonlinear vmas could be handled more efficiently, using
1335 * a placeholder, but handle it in the same way until a need is shown.
1336 * It is important to search the prio_tree before nonlinear list: a vma
1337 * may become nonlinear and be shifted from prio_tree to nonlinear list
1338 * while the lock is dropped; but never shifted from list to prio_tree.
1339 *
1340 * In order to make forward progress despite restarting the search,
1341 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1342 * quickly skip it next time around. Since the prio_tree search only
1343 * shows us those vmas affected by unmapping the range in question, we
1344 * can't efficiently keep all vmas in step with mapping->truncate_count:
1345 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1346 * mapping->truncate_count and vma->vm_truncate_count are protected by
1347 * i_mmap_lock.
1348 *
1349 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001350 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001351 * and restart from that address when we reach that vma again. It might
1352 * have been split or merged, shrunk or extended, but never shifted: so
1353 * restart_addr remains valid so long as it remains in the vma's range.
1354 * unmap_mapping_range forces truncate_count to leap over page-aligned
1355 * values so we can save vma's restart_addr in its truncate_count field.
1356 */
1357#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1358
1359static void reset_vma_truncate_counts(struct address_space *mapping)
1360{
1361 struct vm_area_struct *vma;
1362 struct prio_tree_iter iter;
1363
1364 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1365 vma->vm_truncate_count = 0;
1366 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1367 vma->vm_truncate_count = 0;
1368}
1369
1370static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1371 unsigned long start_addr, unsigned long end_addr,
1372 struct zap_details *details)
1373{
1374 unsigned long restart_addr;
1375 int need_break;
1376
1377again:
1378 restart_addr = vma->vm_truncate_count;
1379 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1380 start_addr = restart_addr;
1381 if (start_addr >= end_addr) {
1382 /* Top of vma has been split off since last time */
1383 vma->vm_truncate_count = details->truncate_count;
1384 return 0;
1385 }
1386 }
1387
Hugh Dickinsee39b372005-04-19 13:29:15 -07001388 restart_addr = zap_page_range(vma, start_addr,
1389 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390
1391 /*
1392 * We cannot rely on the break test in unmap_vmas:
1393 * on the one hand, we don't want to restart our loop
1394 * just because that broke out for the page_table_lock;
1395 * on the other hand, it does no test when vma is small.
1396 */
1397 need_break = need_resched() ||
1398 need_lockbreak(details->i_mmap_lock);
1399
Hugh Dickinsee39b372005-04-19 13:29:15 -07001400 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001401 /* We have now completed this vma: mark it so */
1402 vma->vm_truncate_count = details->truncate_count;
1403 if (!need_break)
1404 return 0;
1405 } else {
1406 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001407 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408 if (!need_break)
1409 goto again;
1410 }
1411
1412 spin_unlock(details->i_mmap_lock);
1413 cond_resched();
1414 spin_lock(details->i_mmap_lock);
1415 return -EINTR;
1416}
1417
1418static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1419 struct zap_details *details)
1420{
1421 struct vm_area_struct *vma;
1422 struct prio_tree_iter iter;
1423 pgoff_t vba, vea, zba, zea;
1424
1425restart:
1426 vma_prio_tree_foreach(vma, &iter, root,
1427 details->first_index, details->last_index) {
1428 /* Skip quickly over those we have already dealt with */
1429 if (vma->vm_truncate_count == details->truncate_count)
1430 continue;
1431
1432 vba = vma->vm_pgoff;
1433 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1434 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1435 zba = details->first_index;
1436 if (zba < vba)
1437 zba = vba;
1438 zea = details->last_index;
1439 if (zea > vea)
1440 zea = vea;
1441
1442 if (unmap_mapping_range_vma(vma,
1443 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1444 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1445 details) < 0)
1446 goto restart;
1447 }
1448}
1449
1450static inline void unmap_mapping_range_list(struct list_head *head,
1451 struct zap_details *details)
1452{
1453 struct vm_area_struct *vma;
1454
1455 /*
1456 * In nonlinear VMAs there is no correspondence between virtual address
1457 * offset and file offset. So we must perform an exhaustive search
1458 * across *all* the pages in each nonlinear VMA, not just the pages
1459 * whose virtual address lies outside the file truncation point.
1460 */
1461restart:
1462 list_for_each_entry(vma, head, shared.vm_set.list) {
1463 /* Skip quickly over those we have already dealt with */
1464 if (vma->vm_truncate_count == details->truncate_count)
1465 continue;
1466 details->nonlinear_vma = vma;
1467 if (unmap_mapping_range_vma(vma, vma->vm_start,
1468 vma->vm_end, details) < 0)
1469 goto restart;
1470 }
1471}
1472
1473/**
1474 * unmap_mapping_range - unmap the portion of all mmaps
1475 * in the specified address_space corresponding to the specified
1476 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001477 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001478 * @holebegin: byte in first page to unmap, relative to the start of
1479 * the underlying file. This will be rounded down to a PAGE_SIZE
1480 * boundary. Note that this is different from vmtruncate(), which
1481 * must keep the partial page. In contrast, we must get rid of
1482 * partial pages.
1483 * @holelen: size of prospective hole in bytes. This will be rounded
1484 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1485 * end of the file.
1486 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1487 * but 0 when invalidating pagecache, don't throw away private data.
1488 */
1489void unmap_mapping_range(struct address_space *mapping,
1490 loff_t const holebegin, loff_t const holelen, int even_cows)
1491{
1492 struct zap_details details;
1493 pgoff_t hba = holebegin >> PAGE_SHIFT;
1494 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1495
1496 /* Check for overflow. */
1497 if (sizeof(holelen) > sizeof(hlen)) {
1498 long long holeend =
1499 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1500 if (holeend & ~(long long)ULONG_MAX)
1501 hlen = ULONG_MAX - hba + 1;
1502 }
1503
1504 details.check_mapping = even_cows? NULL: mapping;
1505 details.nonlinear_vma = NULL;
1506 details.first_index = hba;
1507 details.last_index = hba + hlen - 1;
1508 if (details.last_index < details.first_index)
1509 details.last_index = ULONG_MAX;
1510 details.i_mmap_lock = &mapping->i_mmap_lock;
1511
1512 spin_lock(&mapping->i_mmap_lock);
1513
1514 /* serialize i_size write against truncate_count write */
1515 smp_wmb();
1516 /* Protect against page faults, and endless unmapping loops */
1517 mapping->truncate_count++;
1518 /*
1519 * For archs where spin_lock has inclusive semantics like ia64
1520 * this smp_mb() will prevent to read pagetable contents
1521 * before the truncate_count increment is visible to
1522 * other cpus.
1523 */
1524 smp_mb();
1525 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1526 if (mapping->truncate_count == 0)
1527 reset_vma_truncate_counts(mapping);
1528 mapping->truncate_count++;
1529 }
1530 details.truncate_count = mapping->truncate_count;
1531
1532 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1533 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1534 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1535 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1536 spin_unlock(&mapping->i_mmap_lock);
1537}
1538EXPORT_SYMBOL(unmap_mapping_range);
1539
1540/*
1541 * Handle all mappings that got truncated by a "truncate()"
1542 * system call.
1543 *
1544 * NOTE! We have to be ready to update the memory sharing
1545 * between the file and the memory map for a potential last
1546 * incomplete page. Ugly, but necessary.
1547 */
1548int vmtruncate(struct inode * inode, loff_t offset)
1549{
1550 struct address_space *mapping = inode->i_mapping;
1551 unsigned long limit;
1552
1553 if (inode->i_size < offset)
1554 goto do_expand;
1555 /*
1556 * truncation of in-use swapfiles is disallowed - it would cause
1557 * subsequent swapout to scribble on the now-freed blocks.
1558 */
1559 if (IS_SWAPFILE(inode))
1560 goto out_busy;
1561 i_size_write(inode, offset);
1562 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1563 truncate_inode_pages(mapping, offset);
1564 goto out_truncate;
1565
1566do_expand:
1567 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1568 if (limit != RLIM_INFINITY && offset > limit)
1569 goto out_sig;
1570 if (offset > inode->i_sb->s_maxbytes)
1571 goto out_big;
1572 i_size_write(inode, offset);
1573
1574out_truncate:
1575 if (inode->i_op && inode->i_op->truncate)
1576 inode->i_op->truncate(inode);
1577 return 0;
1578out_sig:
1579 send_sig(SIGXFSZ, current, 0);
1580out_big:
1581 return -EFBIG;
1582out_busy:
1583 return -ETXTBSY;
1584}
1585
1586EXPORT_SYMBOL(vmtruncate);
1587
1588/*
1589 * Primitive swap readahead code. We simply read an aligned block of
1590 * (1 << page_cluster) entries in the swap area. This method is chosen
1591 * because it doesn't cost us any seek time. We also make sure to queue
1592 * the 'original' request together with the readahead ones...
1593 *
1594 * This has been extended to use the NUMA policies from the mm triggering
1595 * the readahead.
1596 *
1597 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1598 */
1599void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1600{
1601#ifdef CONFIG_NUMA
1602 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1603#endif
1604 int i, num;
1605 struct page *new_page;
1606 unsigned long offset;
1607
1608 /*
1609 * Get the number of handles we should do readahead io to.
1610 */
1611 num = valid_swaphandles(entry, &offset);
1612 for (i = 0; i < num; offset++, i++) {
1613 /* Ok, do the async read-ahead now */
1614 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1615 offset), vma, addr);
1616 if (!new_page)
1617 break;
1618 page_cache_release(new_page);
1619#ifdef CONFIG_NUMA
1620 /*
1621 * Find the next applicable VMA for the NUMA policy.
1622 */
1623 addr += PAGE_SIZE;
1624 if (addr == 0)
1625 vma = NULL;
1626 if (vma) {
1627 if (addr >= vma->vm_end) {
1628 vma = next_vma;
1629 next_vma = vma ? vma->vm_next : NULL;
1630 }
1631 if (vma && addr < vma->vm_start)
1632 vma = NULL;
1633 } else {
1634 if (next_vma && addr >= next_vma->vm_start) {
1635 vma = next_vma;
1636 next_vma = vma->vm_next;
1637 }
1638 }
1639#endif
1640 }
1641 lru_add_drain(); /* Push any new pages onto the LRU now */
1642}
1643
1644/*
1645 * We hold the mm semaphore and the page_table_lock on entry and
1646 * should release the pagetable lock on exit..
1647 */
1648static int do_swap_page(struct mm_struct * mm,
1649 struct vm_area_struct * vma, unsigned long address,
1650 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access)
1651{
1652 struct page *page;
1653 swp_entry_t entry = pte_to_swp_entry(orig_pte);
1654 pte_t pte;
1655 int ret = VM_FAULT_MINOR;
1656
1657 pte_unmap(page_table);
1658 spin_unlock(&mm->page_table_lock);
1659 page = lookup_swap_cache(entry);
1660 if (!page) {
1661 swapin_readahead(entry, address, vma);
1662 page = read_swap_cache_async(entry, vma, address);
1663 if (!page) {
1664 /*
1665 * Back out if somebody else faulted in this pte while
1666 * we released the page table lock.
1667 */
1668 spin_lock(&mm->page_table_lock);
1669 page_table = pte_offset_map(pmd, address);
1670 if (likely(pte_same(*page_table, orig_pte)))
1671 ret = VM_FAULT_OOM;
1672 else
1673 ret = VM_FAULT_MINOR;
1674 pte_unmap(page_table);
1675 spin_unlock(&mm->page_table_lock);
1676 goto out;
1677 }
1678
1679 /* Had to read the page from swap area: Major fault */
1680 ret = VM_FAULT_MAJOR;
1681 inc_page_state(pgmajfault);
1682 grab_swap_token();
1683 }
1684
1685 mark_page_accessed(page);
1686 lock_page(page);
1687
1688 /*
1689 * Back out if somebody else faulted in this pte while we
1690 * released the page table lock.
1691 */
1692 spin_lock(&mm->page_table_lock);
1693 page_table = pte_offset_map(pmd, address);
1694 if (unlikely(!pte_same(*page_table, orig_pte))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001695 ret = VM_FAULT_MINOR;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001696 goto out_nomap;
1697 }
1698
1699 if (unlikely(!PageUptodate(page))) {
1700 ret = VM_FAULT_SIGBUS;
1701 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 }
1703
1704 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001705
1706 inc_mm_counter(mm, rss);
1707 pte = mk_pte(page, vma->vm_page_prot);
1708 if (write_access && can_share_swap_page(page)) {
1709 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1710 write_access = 0;
1711 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712
1713 flush_icache_page(vma, page);
1714 set_pte_at(mm, address, page_table, pte);
1715 page_add_anon_rmap(page, vma, address);
1716
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001717 swap_free(entry);
1718 if (vm_swap_full())
1719 remove_exclusive_swap_page(page);
1720 unlock_page(page);
1721
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 if (write_access) {
1723 if (do_wp_page(mm, vma, address,
1724 page_table, pmd, pte) == VM_FAULT_OOM)
1725 ret = VM_FAULT_OOM;
1726 goto out;
1727 }
1728
1729 /* No need to invalidate - it was non-present before */
1730 update_mmu_cache(vma, address, pte);
1731 lazy_mmu_prot_update(pte);
1732 pte_unmap(page_table);
1733 spin_unlock(&mm->page_table_lock);
1734out:
1735 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001736out_nomap:
1737 pte_unmap(page_table);
1738 spin_unlock(&mm->page_table_lock);
1739 unlock_page(page);
1740 page_cache_release(page);
1741 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001742}
1743
1744/*
1745 * We are called with the MM semaphore and page_table_lock
1746 * spinlock held to protect against concurrent faults in
1747 * multithreaded programs.
1748 */
1749static int
1750do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1751 pte_t *page_table, pmd_t *pmd, int write_access,
1752 unsigned long addr)
1753{
1754 pte_t entry;
1755 struct page * page = ZERO_PAGE(addr);
1756
1757 /* Read-only mapping of ZERO_PAGE. */
1758 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
1759
1760 /* ..except if it's a write access */
1761 if (write_access) {
1762 /* Allocate our own private page. */
1763 pte_unmap(page_table);
1764 spin_unlock(&mm->page_table_lock);
1765
1766 if (unlikely(anon_vma_prepare(vma)))
1767 goto no_mem;
1768 page = alloc_zeroed_user_highpage(vma, addr);
1769 if (!page)
1770 goto no_mem;
1771
1772 spin_lock(&mm->page_table_lock);
1773 page_table = pte_offset_map(pmd, addr);
1774
1775 if (!pte_none(*page_table)) {
1776 pte_unmap(page_table);
1777 page_cache_release(page);
1778 spin_unlock(&mm->page_table_lock);
1779 goto out;
1780 }
1781 inc_mm_counter(mm, rss);
1782 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page,
1783 vma->vm_page_prot)),
1784 vma);
1785 lru_cache_add_active(page);
1786 SetPageReferenced(page);
1787 page_add_anon_rmap(page, vma, addr);
1788 }
1789
1790 set_pte_at(mm, addr, page_table, entry);
1791 pte_unmap(page_table);
1792
1793 /* No need to invalidate - it was non-present before */
1794 update_mmu_cache(vma, addr, entry);
1795 lazy_mmu_prot_update(entry);
1796 spin_unlock(&mm->page_table_lock);
1797out:
1798 return VM_FAULT_MINOR;
1799no_mem:
1800 return VM_FAULT_OOM;
1801}
1802
1803/*
1804 * do_no_page() tries to create a new page mapping. It aggressively
1805 * tries to share with existing pages, but makes a separate copy if
1806 * the "write_access" parameter is true in order to avoid the next
1807 * page fault.
1808 *
1809 * As this is called only for pages that do not currently exist, we
1810 * do not need to flush old virtual caches or the TLB.
1811 *
1812 * This is called with the MM semaphore held and the page table
1813 * spinlock held. Exit with the spinlock released.
1814 */
1815static int
1816do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1817 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
1818{
1819 struct page * new_page;
1820 struct address_space *mapping = NULL;
1821 pte_t entry;
1822 unsigned int sequence = 0;
1823 int ret = VM_FAULT_MINOR;
1824 int anon = 0;
1825
1826 if (!vma->vm_ops || !vma->vm_ops->nopage)
1827 return do_anonymous_page(mm, vma, page_table,
1828 pmd, write_access, address);
1829 pte_unmap(page_table);
1830 spin_unlock(&mm->page_table_lock);
1831
1832 if (vma->vm_file) {
1833 mapping = vma->vm_file->f_mapping;
1834 sequence = mapping->truncate_count;
1835 smp_rmb(); /* serializes i_size against truncate_count */
1836 }
1837retry:
1838 cond_resched();
1839 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1840 /*
1841 * No smp_rmb is needed here as long as there's a full
1842 * spin_lock/unlock sequence inside the ->nopage callback
1843 * (for the pagecache lookup) that acts as an implicit
1844 * smp_mb() and prevents the i_size read to happen
1845 * after the next truncate_count read.
1846 */
1847
1848 /* no page was available -- either SIGBUS or OOM */
1849 if (new_page == NOPAGE_SIGBUS)
1850 return VM_FAULT_SIGBUS;
1851 if (new_page == NOPAGE_OOM)
1852 return VM_FAULT_OOM;
1853
1854 /*
1855 * Should we do an early C-O-W break?
1856 */
1857 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1858 struct page *page;
1859
1860 if (unlikely(anon_vma_prepare(vma)))
1861 goto oom;
1862 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1863 if (!page)
1864 goto oom;
1865 copy_user_highpage(page, new_page, address);
1866 page_cache_release(new_page);
1867 new_page = page;
1868 anon = 1;
1869 }
1870
1871 spin_lock(&mm->page_table_lock);
1872 /*
1873 * For a file-backed vma, someone could have truncated or otherwise
1874 * invalidated this page. If unmap_mapping_range got called,
1875 * retry getting the page.
1876 */
1877 if (mapping && unlikely(sequence != mapping->truncate_count)) {
1878 sequence = mapping->truncate_count;
1879 spin_unlock(&mm->page_table_lock);
1880 page_cache_release(new_page);
1881 goto retry;
1882 }
1883 page_table = pte_offset_map(pmd, address);
1884
1885 /*
1886 * This silly early PAGE_DIRTY setting removes a race
1887 * due to the bad i386 page protection. But it's valid
1888 * for other architectures too.
1889 *
1890 * Note that if write_access is true, we either now have
1891 * an exclusive copy of the page, or this is a shared mapping,
1892 * so we can make it writable and dirty to avoid having to
1893 * handle that later.
1894 */
1895 /* Only go through if we didn't race with anybody else... */
1896 if (pte_none(*page_table)) {
1897 if (!PageReserved(new_page))
1898 inc_mm_counter(mm, rss);
1899
1900 flush_icache_page(vma, new_page);
1901 entry = mk_pte(new_page, vma->vm_page_prot);
1902 if (write_access)
1903 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1904 set_pte_at(mm, address, page_table, entry);
1905 if (anon) {
1906 lru_cache_add_active(new_page);
1907 page_add_anon_rmap(new_page, vma, address);
1908 } else
1909 page_add_file_rmap(new_page);
1910 pte_unmap(page_table);
1911 } else {
1912 /* One of our sibling threads was faster, back out. */
1913 pte_unmap(page_table);
1914 page_cache_release(new_page);
1915 spin_unlock(&mm->page_table_lock);
1916 goto out;
1917 }
1918
1919 /* no need to invalidate: a not-present page shouldn't be cached */
1920 update_mmu_cache(vma, address, entry);
1921 lazy_mmu_prot_update(entry);
1922 spin_unlock(&mm->page_table_lock);
1923out:
1924 return ret;
1925oom:
1926 page_cache_release(new_page);
1927 ret = VM_FAULT_OOM;
1928 goto out;
1929}
1930
1931/*
1932 * Fault of a previously existing named mapping. Repopulate the pte
1933 * from the encoded file_pte if possible. This enables swappable
1934 * nonlinear vmas.
1935 */
1936static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma,
1937 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
1938{
1939 unsigned long pgoff;
1940 int err;
1941
1942 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
1943 /*
1944 * Fall back to the linear mapping if the fs does not support
1945 * ->populate:
1946 */
1947 if (!vma->vm_ops || !vma->vm_ops->populate ||
1948 (write_access && !(vma->vm_flags & VM_SHARED))) {
1949 pte_clear(mm, address, pte);
1950 return do_no_page(mm, vma, address, write_access, pte, pmd);
1951 }
1952
1953 pgoff = pte_to_pgoff(*pte);
1954
1955 pte_unmap(pte);
1956 spin_unlock(&mm->page_table_lock);
1957
1958 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
1959 if (err == -ENOMEM)
1960 return VM_FAULT_OOM;
1961 if (err)
1962 return VM_FAULT_SIGBUS;
1963 return VM_FAULT_MAJOR;
1964}
1965
1966/*
1967 * These routines also need to handle stuff like marking pages dirty
1968 * and/or accessed for architectures that don't do it in hardware (most
1969 * RISC architectures). The early dirtying is also good on the i386.
1970 *
1971 * There is also a hook called "update_mmu_cache()" that architectures
1972 * with external mmu caches can use to update those (ie the Sparc or
1973 * PowerPC hashed page tables that act as extended TLBs).
1974 *
1975 * Note the "page_table_lock". It is to protect against kswapd removing
1976 * pages from under us. Note that kswapd only ever _removes_ pages, never
1977 * adds them. As such, once we have noticed that the page is not present,
1978 * we can drop the lock early.
1979 *
1980 * The adding of pages is protected by the MM semaphore (which we hold),
1981 * so we don't need to worry about a page being suddenly been added into
1982 * our VM.
1983 *
1984 * We enter with the pagetable spinlock held, we are supposed to
1985 * release it when done.
1986 */
1987static inline int handle_pte_fault(struct mm_struct *mm,
1988 struct vm_area_struct * vma, unsigned long address,
1989 int write_access, pte_t *pte, pmd_t *pmd)
1990{
1991 pte_t entry;
1992
1993 entry = *pte;
1994 if (!pte_present(entry)) {
1995 /*
1996 * If it truly wasn't present, we know that kswapd
1997 * and the PTE updates will not touch it later. So
1998 * drop the lock.
1999 */
2000 if (pte_none(entry))
2001 return do_no_page(mm, vma, address, write_access, pte, pmd);
2002 if (pte_file(entry))
2003 return do_file_page(mm, vma, address, write_access, pte, pmd);
2004 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
2005 }
2006
2007 if (write_access) {
2008 if (!pte_write(entry))
2009 return do_wp_page(mm, vma, address, pte, pmd, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010 entry = pte_mkdirty(entry);
2011 }
2012 entry = pte_mkyoung(entry);
2013 ptep_set_access_flags(vma, address, pte, entry, write_access);
2014 update_mmu_cache(vma, address, entry);
2015 lazy_mmu_prot_update(entry);
2016 pte_unmap(pte);
2017 spin_unlock(&mm->page_table_lock);
2018 return VM_FAULT_MINOR;
2019}
2020
2021/*
2022 * By the time we get here, we already hold the mm semaphore
2023 */
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002024int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002025 unsigned long address, int write_access)
2026{
2027 pgd_t *pgd;
2028 pud_t *pud;
2029 pmd_t *pmd;
2030 pte_t *pte;
2031
2032 __set_current_state(TASK_RUNNING);
2033
2034 inc_page_state(pgfault);
2035
2036 if (is_vm_hugetlb_page(vma))
2037 return VM_FAULT_SIGBUS; /* mapping truncation does this. */
2038
2039 /*
2040 * We need the page table lock to synchronize with kswapd
2041 * and the SMP-safe atomic PTE updates.
2042 */
2043 pgd = pgd_offset(mm, address);
2044 spin_lock(&mm->page_table_lock);
2045
2046 pud = pud_alloc(mm, pgd, address);
2047 if (!pud)
2048 goto oom;
2049
2050 pmd = pmd_alloc(mm, pud, address);
2051 if (!pmd)
2052 goto oom;
2053
2054 pte = pte_alloc_map(mm, pmd, address);
2055 if (!pte)
2056 goto oom;
2057
2058 return handle_pte_fault(mm, vma, address, write_access, pte, pmd);
2059
2060 oom:
2061 spin_unlock(&mm->page_table_lock);
2062 return VM_FAULT_OOM;
2063}
2064
2065#ifndef __PAGETABLE_PUD_FOLDED
2066/*
2067 * Allocate page upper directory.
2068 *
2069 * We've already handled the fast-path in-line, and we own the
2070 * page table lock.
2071 */
2072pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2073{
2074 pud_t *new;
2075
2076 spin_unlock(&mm->page_table_lock);
2077 new = pud_alloc_one(mm, address);
2078 spin_lock(&mm->page_table_lock);
2079 if (!new)
2080 return NULL;
2081
2082 /*
2083 * Because we dropped the lock, we should re-check the
2084 * entry, as somebody else could have populated it..
2085 */
2086 if (pgd_present(*pgd)) {
2087 pud_free(new);
2088 goto out;
2089 }
2090 pgd_populate(mm, pgd, new);
2091 out:
2092 return pud_offset(pgd, address);
2093}
2094#endif /* __PAGETABLE_PUD_FOLDED */
2095
2096#ifndef __PAGETABLE_PMD_FOLDED
2097/*
2098 * Allocate page middle directory.
2099 *
2100 * We've already handled the fast-path in-line, and we own the
2101 * page table lock.
2102 */
2103pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2104{
2105 pmd_t *new;
2106
2107 spin_unlock(&mm->page_table_lock);
2108 new = pmd_alloc_one(mm, address);
2109 spin_lock(&mm->page_table_lock);
2110 if (!new)
2111 return NULL;
2112
2113 /*
2114 * Because we dropped the lock, we should re-check the
2115 * entry, as somebody else could have populated it..
2116 */
2117#ifndef __ARCH_HAS_4LEVEL_HACK
2118 if (pud_present(*pud)) {
2119 pmd_free(new);
2120 goto out;
2121 }
2122 pud_populate(mm, pud, new);
2123#else
2124 if (pgd_present(*pud)) {
2125 pmd_free(new);
2126 goto out;
2127 }
2128 pgd_populate(mm, pud, new);
2129#endif /* __ARCH_HAS_4LEVEL_HACK */
2130
2131 out:
2132 return pmd_offset(pud, address);
2133}
2134#endif /* __PAGETABLE_PMD_FOLDED */
2135
2136int make_pages_present(unsigned long addr, unsigned long end)
2137{
2138 int ret, len, write;
2139 struct vm_area_struct * vma;
2140
2141 vma = find_vma(current->mm, addr);
2142 if (!vma)
2143 return -1;
2144 write = (vma->vm_flags & VM_WRITE) != 0;
2145 if (addr >= end)
2146 BUG();
2147 if (end > vma->vm_end)
2148 BUG();
2149 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2150 ret = get_user_pages(current, current->mm, addr,
2151 len, write, 0, NULL, NULL);
2152 if (ret < 0)
2153 return ret;
2154 return ret == len ? 0 : -1;
2155}
2156
2157/*
2158 * Map a vmalloc()-space virtual address to the physical page.
2159 */
2160struct page * vmalloc_to_page(void * vmalloc_addr)
2161{
2162 unsigned long addr = (unsigned long) vmalloc_addr;
2163 struct page *page = NULL;
2164 pgd_t *pgd = pgd_offset_k(addr);
2165 pud_t *pud;
2166 pmd_t *pmd;
2167 pte_t *ptep, pte;
2168
2169 if (!pgd_none(*pgd)) {
2170 pud = pud_offset(pgd, addr);
2171 if (!pud_none(*pud)) {
2172 pmd = pmd_offset(pud, addr);
2173 if (!pmd_none(*pmd)) {
2174 ptep = pte_offset_map(pmd, addr);
2175 pte = *ptep;
2176 if (pte_present(pte))
2177 page = pte_page(pte);
2178 pte_unmap(ptep);
2179 }
2180 }
2181 }
2182 return page;
2183}
2184
2185EXPORT_SYMBOL(vmalloc_to_page);
2186
2187/*
2188 * Map a vmalloc()-space virtual address to the physical page frame number.
2189 */
2190unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2191{
2192 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2193}
2194
2195EXPORT_SYMBOL(vmalloc_to_pfn);
2196
2197/*
2198 * update_mem_hiwater
2199 * - update per process rss and vm high water data
2200 */
2201void update_mem_hiwater(struct task_struct *tsk)
2202{
2203 if (tsk->mm) {
2204 unsigned long rss = get_mm_counter(tsk->mm, rss);
2205
2206 if (tsk->mm->hiwater_rss < rss)
2207 tsk->mm->hiwater_rss = rss;
2208 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
2209 tsk->mm->hiwater_vm = tsk->mm->total_vm;
2210 }
2211}
2212
2213#if !defined(__HAVE_ARCH_GATE_AREA)
2214
2215#if defined(AT_SYSINFO_EHDR)
2216struct vm_area_struct gate_vma;
2217
2218static int __init gate_vma_init(void)
2219{
2220 gate_vma.vm_mm = NULL;
2221 gate_vma.vm_start = FIXADDR_USER_START;
2222 gate_vma.vm_end = FIXADDR_USER_END;
2223 gate_vma.vm_page_prot = PAGE_READONLY;
2224 gate_vma.vm_flags = 0;
2225 return 0;
2226}
2227__initcall(gate_vma_init);
2228#endif
2229
2230struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2231{
2232#ifdef AT_SYSINFO_EHDR
2233 return &gate_vma;
2234#else
2235 return NULL;
2236#endif
2237}
2238
2239int in_gate_area_no_task(unsigned long addr)
2240{
2241#ifdef AT_SYSINFO_EHDR
2242 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2243 return 1;
2244#endif
2245 return 0;
2246}
2247
2248#endif /* __HAVE_ARCH_GATE_AREA */