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/acct.h>
50 #include <linux/module.h>
51 #include <linux/init.h>
52
53 #include <asm/pgalloc.h>
54 #include <asm/uaccess.h>
55 #include <asm/tlb.h>
56 #include <asm/tlbflush.h>
57 #include <asm/pgtable.h>
58
59 #include <linux/swapops.h>
60 #include <linux/elf.h>
61
62 #ifndef CONFIG_DISCONTIGMEM
63 /* use the per-pgdat data instead for discontigmem - mbligh */
64 unsigned long max_mapnr;
65 struct page *mem_map;
66
67 EXPORT_SYMBOL(max_mapnr);
68 EXPORT_SYMBOL(mem_map);
69 #endif
70
71 unsigned long num_physpages;
72 /*
73 * A number of key systems in x86 including ioremap() rely on the assumption
74 * that high_memory defines the upper bound on direct map memory, then end
75 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
76 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
77 * and ZONE_HIGHMEM.
78 */
79 void * high_memory;
80 unsigned long vmalloc_earlyreserve;
81
82 EXPORT_SYMBOL(num_physpages);
83 EXPORT_SYMBOL(high_memory);
84 EXPORT_SYMBOL(vmalloc_earlyreserve);
85
86 /*
87 * Note: this doesn't free the actual pages themselves. That
88 * has been handled earlier when unmapping all the memory regions.
89 */
90 static inline void clear_pmd_range(struct mmu_gather *tlb, pmd_t *pmd, unsigned long start, unsigned long end)
91 {
92 struct page *page;
93
94 if (pmd_none(*pmd))
95 return;
96 if (unlikely(pmd_bad(*pmd))) {
97 pmd_ERROR(*pmd);
98 pmd_clear(pmd);
99 return;
100 }
101 if (!((start | end) & ~PMD_MASK)) {
102 /* Only clear full, aligned ranges */
103 page = pmd_page(*pmd);
104 pmd_clear(pmd);
105 dec_page_state(nr_page_table_pages);
106 tlb->mm->nr_ptes--;
107 pte_free_tlb(tlb, page);
108 }
109 }
110
111 static inline void clear_pud_range(struct mmu_gather *tlb, pud_t *pud, unsigned long start, unsigned long end)
112 {
113 unsigned long addr = start, next;
114 pmd_t *pmd, *__pmd;
115
116 if (pud_none(*pud))
117 return;
118 if (unlikely(pud_bad(*pud))) {
119 pud_ERROR(*pud);
120 pud_clear(pud);
121 return;
122 }
123
124 pmd = __pmd = pmd_offset(pud, start);
125 do {
126 next = (addr + PMD_SIZE) & PMD_MASK;
127 if (next > end || next <= addr)
128 next = end;
129
130 clear_pmd_range(tlb, pmd, addr, next);
131 pmd++;
132 addr = next;
133 } while (addr && (addr < end));
134
135 if (!((start | end) & ~PUD_MASK)) {
136 /* Only clear full, aligned ranges */
137 pud_clear(pud);
138 pmd_free_tlb(tlb, __pmd);
139 }
140 }
141
142
143 static inline void clear_pgd_range(struct mmu_gather *tlb, pgd_t *pgd, unsigned long start, unsigned long end)
144 {
145 unsigned long addr = start, next;
146 pud_t *pud, *__pud;
147
148 if (pgd_none(*pgd))
149 return;
150 if (unlikely(pgd_bad(*pgd))) {
151 pgd_ERROR(*pgd);
152 pgd_clear(pgd);
153 return;
154 }
155
156 pud = __pud = pud_offset(pgd, start);
157 do {
158 next = (addr + PUD_SIZE) & PUD_MASK;
159 if (next > end || next <= addr)
160 next = end;
161
162 clear_pud_range(tlb, pud, addr, next);
163 pud++;
164 addr = next;
165 } while (addr && (addr < end));
166
167 if (!((start | end) & ~PGDIR_MASK)) {
168 /* Only clear full, aligned ranges */
169 pgd_clear(pgd);
170 pud_free_tlb(tlb, __pud);
171 }
172 }
173
174 /*
175 * This function clears user-level page tables of a process.
176 *
177 * Must be called with pagetable lock held.
178 */
179 void clear_page_range(struct mmu_gather *tlb, unsigned long start, unsigned long end)
180 {
181 unsigned long addr = start, next;
182 pgd_t * pgd = pgd_offset(tlb->mm, start);
183 unsigned long i;
184
185 for (i = pgd_index(start); i <= pgd_index(end-1); i++) {
186 next = (addr + PGDIR_SIZE) & PGDIR_MASK;
187 if (next > end || next <= addr)
188 next = end;
189
190 clear_pgd_range(tlb, pgd, addr, next);
191 pgd++;
192 addr = next;
193 }
194 }
195
196 pte_t fastcall * pte_alloc_map(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
197 {
198 if (!pmd_present(*pmd)) {
199 struct page *new;
200
201 spin_unlock(&mm->page_table_lock);
202 new = pte_alloc_one(mm, address);
203 spin_lock(&mm->page_table_lock);
204 if (!new)
205 return NULL;
206 /*
207 * Because we dropped the lock, we should re-check the
208 * entry, as somebody else could have populated it..
209 */
210 if (pmd_present(*pmd)) {
211 pte_free(new);
212 goto out;
213 }
214 mm->nr_ptes++;
215 inc_page_state(nr_page_table_pages);
216 pmd_populate(mm, pmd, new);
217 }
218 out:
219 return pte_offset_map(pmd, address);
220 }
221
222 pte_t fastcall * pte_alloc_kernel(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
223 {
224 if (!pmd_present(*pmd)) {
225 pte_t *new;
226
227 spin_unlock(&mm->page_table_lock);
228 new = pte_alloc_one_kernel(mm, address);
229 spin_lock(&mm->page_table_lock);
230 if (!new)
231 return NULL;
232
233 /*
234 * Because we dropped the lock, we should re-check the
235 * entry, as somebody else could have populated it..
236 */
237 if (pmd_present(*pmd)) {
238 pte_free_kernel(new);
239 goto out;
240 }
241 pmd_populate_kernel(mm, pmd, new);
242 }
243 out:
244 return pte_offset_kernel(pmd, address);
245 }
246
247 /*
248 * copy one vm_area from one task to the other. Assumes the page tables
249 * already present in the new task to be cleared in the whole range
250 * covered by this vma.
251 *
252 * dst->page_table_lock is held on entry and exit,
253 * but may be dropped within p[mg]d_alloc() and pte_alloc_map().
254 */
255
256 static inline void
257 copy_swap_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, pte_t pte)
258 {
259 if (pte_file(pte))
260 return;
261 swap_duplicate(pte_to_swp_entry(pte));
262 if (list_empty(&dst_mm->mmlist)) {
263 spin_lock(&mmlist_lock);
264 list_add(&dst_mm->mmlist, &src_mm->mmlist);
265 spin_unlock(&mmlist_lock);
266 }
267 }
268
269 static inline void
270 copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
271 pte_t *dst_pte, pte_t *src_pte, unsigned long vm_flags,
272 unsigned long addr)
273 {
274 pte_t pte = *src_pte;
275 struct page *page;
276 unsigned long pfn;
277
278 /* pte contains position in swap, so copy. */
279 if (!pte_present(pte)) {
280 copy_swap_pte(dst_mm, src_mm, pte);
281 set_pte(dst_pte, pte);
282 return;
283 }
284 pfn = pte_pfn(pte);
285 /* the pte points outside of valid memory, the
286 * mapping is assumed to be good, meaningful
287 * and not mapped via rmap - duplicate the
288 * mapping as is.
289 */
290 page = NULL;
291 if (pfn_valid(pfn))
292 page = pfn_to_page(pfn);
293
294 if (!page || PageReserved(page)) {
295 set_pte(dst_pte, pte);
296 return;
297 }
298
299 /*
300 * If it's a COW mapping, write protect it both
301 * in the parent and the child
302 */
303 if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) {
304 ptep_set_wrprotect(src_pte);
305 pte = *src_pte;
306 }
307
308 /*
309 * If it's a shared mapping, mark it clean in
310 * the child
311 */
312 if (vm_flags & VM_SHARED)
313 pte = pte_mkclean(pte);
314 pte = pte_mkold(pte);
315 get_page(page);
316 dst_mm->rss++;
317 if (PageAnon(page))
318 dst_mm->anon_rss++;
319 set_pte(dst_pte, pte);
320 page_dup_rmap(page);
321 }
322
323 static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
324 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
325 unsigned long addr, unsigned long end)
326 {
327 pte_t *src_pte, *dst_pte;
328 pte_t *s, *d;
329 unsigned long vm_flags = vma->vm_flags;
330
331 d = dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr);
332 if (!dst_pte)
333 return -ENOMEM;
334
335 spin_lock(&src_mm->page_table_lock);
336 s = src_pte = pte_offset_map_nested(src_pmd, addr);
337 for (; addr < end; addr += PAGE_SIZE, s++, d++) {
338 if (pte_none(*s))
339 continue;
340 copy_one_pte(dst_mm, src_mm, d, s, vm_flags, addr);
341 }
342 pte_unmap_nested(src_pte);
343 pte_unmap(dst_pte);
344 spin_unlock(&src_mm->page_table_lock);
345 cond_resched_lock(&dst_mm->page_table_lock);
346 return 0;
347 }
348
349 static int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
350 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
351 unsigned long addr, unsigned long end)
352 {
353 pmd_t *src_pmd, *dst_pmd;
354 int err = 0;
355 unsigned long next;
356
357 src_pmd = pmd_offset(src_pud, addr);
358 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
359 if (!dst_pmd)
360 return -ENOMEM;
361
362 for (; addr < end; addr = next, src_pmd++, dst_pmd++) {
363 next = (addr + PMD_SIZE) & PMD_MASK;
364 if (next > end || next <= addr)
365 next = end;
366 if (pmd_none(*src_pmd))
367 continue;
368 if (pmd_bad(*src_pmd)) {
369 pmd_ERROR(*src_pmd);
370 pmd_clear(src_pmd);
371 continue;
372 }
373 err = copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
374 vma, addr, next);
375 if (err)
376 break;
377 }
378 return err;
379 }
380
381 static int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
382 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
383 unsigned long addr, unsigned long end)
384 {
385 pud_t *src_pud, *dst_pud;
386 int err = 0;
387 unsigned long next;
388
389 src_pud = pud_offset(src_pgd, addr);
390 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
391 if (!dst_pud)
392 return -ENOMEM;
393
394 for (; addr < end; addr = next, src_pud++, dst_pud++) {
395 next = (addr + PUD_SIZE) & PUD_MASK;
396 if (next > end || next <= addr)
397 next = end;
398 if (pud_none(*src_pud))
399 continue;
400 if (pud_bad(*src_pud)) {
401 pud_ERROR(*src_pud);
402 pud_clear(src_pud);
403 continue;
404 }
405 err = copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
406 vma, addr, next);
407 if (err)
408 break;
409 }
410 return err;
411 }
412
413 int copy_page_range(struct mm_struct *dst, struct mm_struct *src,
414 struct vm_area_struct *vma)
415 {
416 pgd_t *src_pgd, *dst_pgd;
417 unsigned long addr, start, end, next;
418 int err = 0;
419
420 if (is_vm_hugetlb_page(vma))
421 return copy_hugetlb_page_range(dst, src, vma);
422
423 start = vma->vm_start;
424 src_pgd = pgd_offset(src, start);
425 dst_pgd = pgd_offset(dst, start);
426
427 end = vma->vm_end;
428 addr = start;
429 while (addr && (addr < end-1)) {
430 next = (addr + PGDIR_SIZE) & PGDIR_MASK;
431 if (next > end || next <= addr)
432 next = end;
433 if (pgd_none(*src_pgd))
434 goto next_pgd;
435 if (pgd_bad(*src_pgd)) {
436 pgd_ERROR(*src_pgd);
437 pgd_clear(src_pgd);
438 goto next_pgd;
439 }
440 err = copy_pud_range(dst, src, dst_pgd, src_pgd,
441 vma, addr, next);
442 if (err)
443 break;
444
445 next_pgd:
446 src_pgd++;
447 dst_pgd++;
448 addr = next;
449 }
450
451 return err;
452 }
453
454 static void zap_pte_range(struct mmu_gather *tlb,
455 pmd_t *pmd, unsigned long address,
456 unsigned long size, struct zap_details *details)
457 {
458 unsigned long offset;
459 pte_t *ptep;
460
461 if (pmd_none(*pmd))
462 return;
463 if (unlikely(pmd_bad(*pmd))) {
464 pmd_ERROR(*pmd);
465 pmd_clear(pmd);
466 return;
467 }
468 ptep = pte_offset_map(pmd, address);
469 offset = address & ~PMD_MASK;
470 if (offset + size > PMD_SIZE)
471 size = PMD_SIZE - offset;
472 size &= PAGE_MASK;
473 if (details && !details->check_mapping && !details->nonlinear_vma)
474 details = NULL;
475 for (offset=0; offset < size; ptep++, offset += PAGE_SIZE) {
476 pte_t pte = *ptep;
477 if (pte_none(pte))
478 continue;
479 if (pte_present(pte)) {
480 struct page *page = NULL;
481 unsigned long pfn = pte_pfn(pte);
482 if (pfn_valid(pfn)) {
483 page = pfn_to_page(pfn);
484 if (PageReserved(page))
485 page = NULL;
486 }
487 if (unlikely(details) && page) {
488 /*
489 * unmap_shared_mapping_pages() wants to
490 * invalidate cache without truncating:
491 * unmap shared but keep private pages.
492 */
493 if (details->check_mapping &&
494 details->check_mapping != page->mapping)
495 continue;
496 /*
497 * Each page->index must be checked when
498 * invalidating or truncating nonlinear.
499 */
500 if (details->nonlinear_vma &&
501 (page->index < details->first_index ||
502 page->index > details->last_index))
503 continue;
504 }
505 pte = ptep_get_and_clear(ptep);
506 tlb_remove_tlb_entry(tlb, ptep, address+offset);
507 if (unlikely(!page))
508 continue;
509 if (unlikely(details) && details->nonlinear_vma
510 && linear_page_index(details->nonlinear_vma,
511 address+offset) != page->index)
512 set_pte(ptep, pgoff_to_pte(page->index));
513 if (pte_dirty(pte))
514 set_page_dirty(page);
515 if (PageAnon(page))
516 tlb->mm->anon_rss--;
517 else if (pte_young(pte))
518 mark_page_accessed(page);
519 tlb->freed++;
520 page_remove_rmap(page);
521 tlb_remove_page(tlb, page);
522 continue;
523 }
524 /*
525 * If details->check_mapping, we leave swap entries;
526 * if details->nonlinear_vma, we leave file entries.
527 */
528 if (unlikely(details))
529 continue;
530 if (!pte_file(pte))
531 free_swap_and_cache(pte_to_swp_entry(pte));
532 pte_clear(ptep);
533 }
534 pte_unmap(ptep-1);
535 }
536
537 static void zap_pmd_range(struct mmu_gather *tlb,
538 pud_t *pud, unsigned long address,
539 unsigned long size, struct zap_details *details)
540 {
541 pmd_t * pmd;
542 unsigned long end;
543
544 if (pud_none(*pud))
545 return;
546 if (unlikely(pud_bad(*pud))) {
547 pud_ERROR(*pud);
548 pud_clear(pud);
549 return;
550 }
551 pmd = pmd_offset(pud, address);
552 end = address + size;
553 if (end > ((address + PUD_SIZE) & PUD_MASK))
554 end = ((address + PUD_SIZE) & PUD_MASK);
555 do {
556 zap_pte_range(tlb, pmd, address, end - address, details);
557 address = (address + PMD_SIZE) & PMD_MASK;
558 pmd++;
559 } while (address && (address < end));
560 }
561
562 static void zap_pud_range(struct mmu_gather *tlb,
563 pgd_t * pgd, unsigned long address,
564 unsigned long end, struct zap_details *details)
565 {
566 pud_t * pud;
567
568 if (pgd_none(*pgd))
569 return;
570 if (unlikely(pgd_bad(*pgd))) {
571 pgd_ERROR(*pgd);
572 pgd_clear(pgd);
573 return;
574 }
575 pud = pud_offset(pgd, address);
576 do {
577 zap_pmd_range(tlb, pud, address, end - address, details);
578 address = (address + PUD_SIZE) & PUD_MASK;
579 pud++;
580 } while (address && (address < end));
581 }
582
583 static void unmap_page_range(struct mmu_gather *tlb,
584 struct vm_area_struct *vma, unsigned long address,
585 unsigned long end, struct zap_details *details)
586 {
587 unsigned long next;
588 pgd_t *pgd;
589 int i;
590
591 BUG_ON(address >= end);
592 pgd = pgd_offset(vma->vm_mm, address);
593 tlb_start_vma(tlb, vma);
594 for (i = pgd_index(address); i <= pgd_index(end-1); i++) {
595 next = (address + PGDIR_SIZE) & PGDIR_MASK;
596 if (next <= address || next > end)
597 next = end;
598 zap_pud_range(tlb, pgd, address, next, details);
599 address = next;
600 pgd++;
601 }
602 tlb_end_vma(tlb, vma);
603 }
604
605 #ifdef CONFIG_PREEMPT
606 # define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
607 #else
608 /* No preempt: go for improved straight-line efficiency */
609 # define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
610 #endif
611
612 /**
613 * unmap_vmas - unmap a range of memory covered by a list of vma's
614 * @tlbp: address of the caller's struct mmu_gather
615 * @mm: the controlling mm_struct
616 * @vma: the starting vma
617 * @start_addr: virtual address at which to start unmapping
618 * @end_addr: virtual address at which to end unmapping
619 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
620 * @details: details of nonlinear truncation or shared cache invalidation
621 *
622 * Returns the number of vma's which were covered by the unmapping.
623 *
624 * Unmap all pages in the vma list. Called under page_table_lock.
625 *
626 * We aim to not hold page_table_lock for too long (for scheduling latency
627 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
628 * return the ending mmu_gather to the caller.
629 *
630 * Only addresses between `start' and `end' will be unmapped.
631 *
632 * The VMA list must be sorted in ascending virtual address order.
633 *
634 * unmap_vmas() assumes that the caller will flush the whole unmapped address
635 * range after unmap_vmas() returns. So the only responsibility here is to
636 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
637 * drops the lock and schedules.
638 */
639 int unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
640 struct vm_area_struct *vma, unsigned long start_addr,
641 unsigned long end_addr, unsigned long *nr_accounted,
642 struct zap_details *details)
643 {
644 unsigned long zap_bytes = ZAP_BLOCK_SIZE;
645 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
646 int tlb_start_valid = 0;
647 int ret = 0;
648 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
649 int fullmm = tlb_is_full_mm(*tlbp);
650
651 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
652 unsigned long start;
653 unsigned long end;
654
655 start = max(vma->vm_start, start_addr);
656 if (start >= vma->vm_end)
657 continue;
658 end = min(vma->vm_end, end_addr);
659 if (end <= vma->vm_start)
660 continue;
661
662 if (vma->vm_flags & VM_ACCOUNT)
663 *nr_accounted += (end - start) >> PAGE_SHIFT;
664
665 ret++;
666 while (start != end) {
667 unsigned long block;
668
669 if (!tlb_start_valid) {
670 tlb_start = start;
671 tlb_start_valid = 1;
672 }
673
674 if (is_vm_hugetlb_page(vma)) {
675 block = end - start;
676 unmap_hugepage_range(vma, start, end);
677 } else {
678 block = min(zap_bytes, end - start);
679 unmap_page_range(*tlbp, vma, start,
680 start + block, details);
681 }
682
683 start += block;
684 zap_bytes -= block;
685 if ((long)zap_bytes > 0)
686 continue;
687
688 tlb_finish_mmu(*tlbp, tlb_start, start);
689
690 if (need_resched() ||
691 need_lockbreak(&mm->page_table_lock) ||
692 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
693 if (i_mmap_lock) {
694 /* must reset count of rss freed */
695 *tlbp = tlb_gather_mmu(mm, fullmm);
696 details->break_addr = start;
697 goto out;
698 }
699 spin_unlock(&mm->page_table_lock);
700 cond_resched();
701 spin_lock(&mm->page_table_lock);
702 }
703
704 *tlbp = tlb_gather_mmu(mm, fullmm);
705 tlb_start_valid = 0;
706 zap_bytes = ZAP_BLOCK_SIZE;
707 }
708 }
709 out:
710 return ret;
711 }
712
713 /**
714 * zap_page_range - remove user pages in a given range
715 * @vma: vm_area_struct holding the applicable pages
716 * @address: starting address of pages to zap
717 * @size: number of bytes to zap
718 * @details: details of nonlinear truncation or shared cache invalidation
719 */
720 void zap_page_range(struct vm_area_struct *vma, unsigned long address,
721 unsigned long size, struct zap_details *details)
722 {
723 struct mm_struct *mm = vma->vm_mm;
724 struct mmu_gather *tlb;
725 unsigned long end = address + size;
726 unsigned long nr_accounted = 0;
727
728 if (is_vm_hugetlb_page(vma)) {
729 zap_hugepage_range(vma, address, size);
730 return;
731 }
732
733 lru_add_drain();
734 spin_lock(&mm->page_table_lock);
735 tlb = tlb_gather_mmu(mm, 0);
736 unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
737 tlb_finish_mmu(tlb, address, end);
738 acct_update_integrals();
739 spin_unlock(&mm->page_table_lock);
740 }
741
742 /*
743 * Do a quick page-table lookup for a single page.
744 * mm->page_table_lock must be held.
745 */
746 static struct page *
747 __follow_page(struct mm_struct *mm, unsigned long address, int read, int write)
748 {
749 pgd_t *pgd;
750 pud_t *pud;
751 pmd_t *pmd;
752 pte_t *ptep, pte;
753 unsigned long pfn;
754 struct page *page;
755
756 page = follow_huge_addr(mm, address, write);
757 if (! IS_ERR(page))
758 return page;
759
760 pgd = pgd_offset(mm, address);
761 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
762 goto out;
763
764 pud = pud_offset(pgd, address);
765 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
766 goto out;
767
768 pmd = pmd_offset(pud, address);
769 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
770 goto out;
771 if (pmd_huge(*pmd))
772 return follow_huge_pmd(mm, address, pmd, write);
773
774 ptep = pte_offset_map(pmd, address);
775 if (!ptep)
776 goto out;
777
778 pte = *ptep;
779 pte_unmap(ptep);
780 if (pte_present(pte)) {
781 if (write && !pte_write(pte))
782 goto out;
783 if (read && !pte_read(pte))
784 goto out;
785 pfn = pte_pfn(pte);
786 if (pfn_valid(pfn)) {
787 page = pfn_to_page(pfn);
788 if (write && !pte_dirty(pte) && !PageDirty(page))
789 set_page_dirty(page);
790 mark_page_accessed(page);
791 return page;
792 }
793 }
794
795 out:
796 return NULL;
797 }
798
799 struct page *
800 follow_page(struct mm_struct *mm, unsigned long address, int write)
801 {
802 return __follow_page(mm, address, /*read*/0, write);
803 }
804
805 int
806 check_user_page_readable(struct mm_struct *mm, unsigned long address)
807 {
808 return __follow_page(mm, address, /*read*/1, /*write*/0) != NULL;
809 }
810
811 EXPORT_SYMBOL(check_user_page_readable);
812
813 /*
814 * Given a physical address, is there a useful struct page pointing to
815 * it? This may become more complex in the future if we start dealing
816 * with IO-aperture pages for direct-IO.
817 */
818
819 static inline struct page *get_page_map(struct page *page)
820 {
821 if (!pfn_valid(page_to_pfn(page)))
822 return NULL;
823 return page;
824 }
825
826
827 static inline int
828 untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
829 unsigned long address)
830 {
831 pgd_t *pgd;
832 pud_t *pud;
833 pmd_t *pmd;
834
835 /* Check if the vma is for an anonymous mapping. */
836 if (vma->vm_ops && vma->vm_ops->nopage)
837 return 0;
838
839 /* Check if page directory entry exists. */
840 pgd = pgd_offset(mm, address);
841 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
842 return 1;
843
844 pud = pud_offset(pgd, address);
845 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
846 return 1;
847
848 /* Check if page middle directory entry exists. */
849 pmd = pmd_offset(pud, address);
850 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
851 return 1;
852
853 /* There is a pte slot for 'address' in 'mm'. */
854 return 0;
855 }
856
857
858 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
859 unsigned long start, int len, int write, int force,
860 struct page **pages, struct vm_area_struct **vmas)
861 {
862 int i;
863 unsigned int flags;
864
865 /*
866 * Require read or write permissions.
867 * If 'force' is set, we only require the "MAY" flags.
868 */
869 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
870 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
871 i = 0;
872
873 do {
874 struct vm_area_struct * vma;
875
876 vma = find_extend_vma(mm, start);
877 if (!vma && in_gate_area(tsk, start)) {
878 unsigned long pg = start & PAGE_MASK;
879 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
880 pgd_t *pgd;
881 pud_t *pud;
882 pmd_t *pmd;
883 pte_t *pte;
884 if (write) /* user gate pages are read-only */
885 return i ? : -EFAULT;
886 if (pg > TASK_SIZE)
887 pgd = pgd_offset_k(pg);
888 else
889 pgd = pgd_offset_gate(mm, pg);
890 BUG_ON(pgd_none(*pgd));
891 pud = pud_offset(pgd, pg);
892 BUG_ON(pud_none(*pud));
893 pmd = pmd_offset(pud, pg);
894 BUG_ON(pmd_none(*pmd));
895 pte = pte_offset_map(pmd, pg);
896 BUG_ON(pte_none(*pte));
897 if (pages) {
898 pages[i] = pte_page(*pte);
899 get_page(pages[i]);
900 }
901 pte_unmap(pte);
902 if (vmas)
903 vmas[i] = gate_vma;
904 i++;
905 start += PAGE_SIZE;
906 len--;
907 continue;
908 }
909
910 if (!vma || (vma->vm_flags & VM_IO)
911 || !(flags & vma->vm_flags))
912 return i ? : -EFAULT;
913
914 if (is_vm_hugetlb_page(vma)) {
915 i = follow_hugetlb_page(mm, vma, pages, vmas,
916 &start, &len, i);
917 continue;
918 }
919 spin_lock(&mm->page_table_lock);
920 do {
921 struct page *map;
922 int lookup_write = write;
923
924 cond_resched_lock(&mm->page_table_lock);
925 while (!(map = follow_page(mm, start, lookup_write))) {
926 /*
927 * Shortcut for anonymous pages. We don't want
928 * to force the creation of pages tables for
929 * insanly big anonymously mapped areas that
930 * nobody touched so far. This is important
931 * for doing a core dump for these mappings.
932 */
933 if (!lookup_write &&
934 untouched_anonymous_page(mm,vma,start)) {
935 map = ZERO_PAGE(start);
936 break;
937 }
938 spin_unlock(&mm->page_table_lock);
939 switch (handle_mm_fault(mm,vma,start,write)) {
940 case VM_FAULT_MINOR:
941 tsk->min_flt++;
942 break;
943 case VM_FAULT_MAJOR:
944 tsk->maj_flt++;
945 break;
946 case VM_FAULT_SIGBUS:
947 return i ? i : -EFAULT;
948 case VM_FAULT_OOM:
949 return i ? i : -ENOMEM;
950 default:
951 BUG();
952 }
953 /*
954 * Now that we have performed a write fault
955 * and surely no longer have a shared page we
956 * shouldn't write, we shouldn't ignore an
957 * unwritable page in the page table if
958 * we are forcing write access.
959 */
960 lookup_write = write && !force;
961 spin_lock(&mm->page_table_lock);
962 }
963 if (pages) {
964 pages[i] = get_page_map(map);
965 if (!pages[i]) {
966 spin_unlock(&mm->page_table_lock);
967 while (i--)
968 page_cache_release(pages[i]);
969 i = -EFAULT;
970 goto out;
971 }
972 flush_dcache_page(pages[i]);
973 if (!PageReserved(pages[i]))
974 page_cache_get(pages[i]);
975 }
976 if (vmas)
977 vmas[i] = vma;
978 i++;
979 start += PAGE_SIZE;
980 len--;
981 } while(len && start < vma->vm_end);
982 spin_unlock(&mm->page_table_lock);
983 } while(len);
984 out:
985 return i;
986 }
987
988 EXPORT_SYMBOL(get_user_pages);
989
990 static void zeromap_pte_range(pte_t * pte, unsigned long address,
991 unsigned long size, pgprot_t prot)
992 {
993 unsigned long end;
994
995 address &= ~PMD_MASK;
996 end = address + size;
997 if (end > PMD_SIZE)
998 end = PMD_SIZE;
999 do {
1000 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(address), prot));
1001 BUG_ON(!pte_none(*pte));
1002 set_pte(pte, zero_pte);
1003 address += PAGE_SIZE;
1004 pte++;
1005 } while (address && (address < end));
1006 }
1007
1008 static inline int zeromap_pmd_range(struct mm_struct *mm, pmd_t * pmd,
1009 unsigned long address, unsigned long size, pgprot_t prot)
1010 {
1011 unsigned long base, end;
1012
1013 base = address & PUD_MASK;
1014 address &= ~PUD_MASK;
1015 end = address + size;
1016 if (end > PUD_SIZE)
1017 end = PUD_SIZE;
1018 do {
1019 pte_t * pte = pte_alloc_map(mm, pmd, base + address);
1020 if (!pte)
1021 return -ENOMEM;
1022 zeromap_pte_range(pte, base + address, end - address, prot);
1023 pte_unmap(pte);
1024 address = (address + PMD_SIZE) & PMD_MASK;
1025 pmd++;
1026 } while (address && (address < end));
1027 return 0;
1028 }
1029
1030 static inline int zeromap_pud_range(struct mm_struct *mm, pud_t * pud,
1031 unsigned long address,
1032 unsigned long size, pgprot_t prot)
1033 {
1034 unsigned long base, end;
1035 int error = 0;
1036
1037 base = address & PGDIR_MASK;
1038 address &= ~PGDIR_MASK;
1039 end = address + size;
1040 if (end > PGDIR_SIZE)
1041 end = PGDIR_SIZE;
1042 do {
1043 pmd_t * pmd = pmd_alloc(mm, pud, base + address);
1044 error = -ENOMEM;
1045 if (!pmd)
1046 break;
1047 error = zeromap_pmd_range(mm, pmd, base + address,
1048 end - address, prot);
1049 if (error)
1050 break;
1051 address = (address + PUD_SIZE) & PUD_MASK;
1052 pud++;
1053 } while (address && (address < end));
1054 return 0;
1055 }
1056
1057 int zeromap_page_range(struct vm_area_struct *vma, unsigned long address,
1058 unsigned long size, pgprot_t prot)
1059 {
1060 int i;
1061 int error = 0;
1062 pgd_t * pgd;
1063 unsigned long beg = address;
1064 unsigned long end = address + size;
1065 unsigned long next;
1066 struct mm_struct *mm = vma->vm_mm;
1067
1068 pgd = pgd_offset(mm, address);
1069 flush_cache_range(vma, beg, end);
1070 BUG_ON(address >= end);
1071 BUG_ON(end > vma->vm_end);
1072
1073 spin_lock(&mm->page_table_lock);
1074 for (i = pgd_index(address); i <= pgd_index(end-1); i++) {
1075 pud_t *pud = pud_alloc(mm, pgd, address);
1076 error = -ENOMEM;
1077 if (!pud)
1078 break;
1079 next = (address + PGDIR_SIZE) & PGDIR_MASK;
1080 if (next <= beg || next > end)
1081 next = end;
1082 error = zeromap_pud_range(mm, pud, address,
1083 next - address, prot);
1084 if (error)
1085 break;
1086 address = next;
1087 pgd++;
1088 }
1089 /*
1090 * Why flush? zeromap_pte_range has a BUG_ON for !pte_none()
1091 */
1092 flush_tlb_range(vma, beg, end);
1093 spin_unlock(&mm->page_table_lock);
1094 return error;
1095 }
1096
1097 /*
1098 * maps a range of physical memory into the requested pages. the old
1099 * mappings are removed. any references to nonexistent pages results
1100 * in null mappings (currently treated as "copy-on-access")
1101 */
1102 static inline void
1103 remap_pte_range(pte_t * pte, unsigned long address, unsigned long size,
1104 unsigned long pfn, pgprot_t prot)
1105 {
1106 unsigned long end;
1107
1108 address &= ~PMD_MASK;
1109 end = address + size;
1110 if (end > PMD_SIZE)
1111 end = PMD_SIZE;
1112 do {
1113 BUG_ON(!pte_none(*pte));
1114 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
1115 set_pte(pte, pfn_pte(pfn, prot));
1116 address += PAGE_SIZE;
1117 pfn++;
1118 pte++;
1119 } while (address && (address < end));
1120 }
1121
1122 static inline int
1123 remap_pmd_range(struct mm_struct *mm, pmd_t * pmd, unsigned long address,
1124 unsigned long size, unsigned long pfn, pgprot_t prot)
1125 {
1126 unsigned long base, end;
1127
1128 base = address & PUD_MASK;
1129 address &= ~PUD_MASK;
1130 end = address + size;
1131 if (end > PUD_SIZE)
1132 end = PUD_SIZE;
1133 pfn -= (address >> PAGE_SHIFT);
1134 do {
1135 pte_t * pte = pte_alloc_map(mm, pmd, base + address);
1136 if (!pte)
1137 return -ENOMEM;
1138 remap_pte_range(pte, base + address, end - address,
1139 (address >> PAGE_SHIFT) + pfn, prot);
1140 pte_unmap(pte);
1141 address = (address + PMD_SIZE) & PMD_MASK;
1142 pmd++;
1143 } while (address && (address < end));
1144 return 0;
1145 }
1146
1147 static inline int remap_pud_range(struct mm_struct *mm, pud_t * pud,
1148 unsigned long address, unsigned long size,
1149 unsigned long pfn, pgprot_t prot)
1150 {
1151 unsigned long base, end;
1152 int error;
1153
1154 base = address & PGDIR_MASK;
1155 address &= ~PGDIR_MASK;
1156 end = address + size;
1157 if (end > PGDIR_SIZE)
1158 end = PGDIR_SIZE;
1159 pfn -= address >> PAGE_SHIFT;
1160 do {
1161 pmd_t *pmd = pmd_alloc(mm, pud, base+address);
1162 error = -ENOMEM;
1163 if (!pmd)
1164 break;
1165 error = remap_pmd_range(mm, pmd, base + address, end - address,
1166 (address >> PAGE_SHIFT) + pfn, prot);
1167 if (error)
1168 break;
1169 address = (address + PUD_SIZE) & PUD_MASK;
1170 pud++;
1171 } while (address && (address < end));
1172 return error;
1173 }
1174
1175 /* Note: this is only safe if the mm semaphore is held when called. */
1176 int remap_pfn_range(struct vm_area_struct *vma, unsigned long from,
1177 unsigned long pfn, unsigned long size, pgprot_t prot)
1178 {
1179 int error = 0;
1180 pgd_t *pgd;
1181 unsigned long beg = from;
1182 unsigned long end = from + size;
1183 unsigned long next;
1184 struct mm_struct *mm = vma->vm_mm;
1185 int i;
1186
1187 pfn -= from >> PAGE_SHIFT;
1188 pgd = pgd_offset(mm, from);
1189 flush_cache_range(vma, beg, end);
1190 BUG_ON(from >= end);
1191
1192 /*
1193 * Physically remapped pages are special. Tell the
1194 * rest of the world about it:
1195 * VM_IO tells people not to look at these pages
1196 * (accesses can have side effects).
1197 * VM_RESERVED tells swapout not to try to touch
1198 * this region.
1199 */
1200 vma->vm_flags |= VM_IO | VM_RESERVED;
1201
1202 spin_lock(&mm->page_table_lock);
1203 for (i = pgd_index(beg); i <= pgd_index(end-1); i++) {
1204 pud_t *pud = pud_alloc(mm, pgd, from);
1205 error = -ENOMEM;
1206 if (!pud)
1207 break;
1208 next = (from + PGDIR_SIZE) & PGDIR_MASK;
1209 if (next > end || next <= from)
1210 next = end;
1211 error = remap_pud_range(mm, pud, from, end - from,
1212 pfn + (from >> PAGE_SHIFT), prot);
1213 if (error)
1214 break;
1215 from = next;
1216 pgd++;
1217 }
1218 /*
1219 * Why flush? remap_pte_range has a BUG_ON for !pte_none()
1220 */
1221 flush_tlb_range(vma, beg, end);
1222 spin_unlock(&mm->page_table_lock);
1223
1224 return error;
1225 }
1226
1227 EXPORT_SYMBOL(remap_pfn_range);
1228
1229 /*
1230 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1231 * servicing faults for write access. In the normal case, do always want
1232 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1233 * that do not have writing enabled, when used by access_process_vm.
1234 */
1235 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1236 {
1237 if (likely(vma->vm_flags & VM_WRITE))
1238 pte = pte_mkwrite(pte);
1239 return pte;
1240 }
1241
1242 /*
1243 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
1244 */
1245 static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address,
1246 pte_t *page_table)
1247 {
1248 pte_t entry;
1249
1250 flush_cache_page(vma, address);
1251 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)),
1252 vma);
1253 ptep_establish(vma, address, page_table, entry);
1254 update_mmu_cache(vma, address, entry);
1255 }
1256
1257 /*
1258 * This routine handles present pages, when users try to write
1259 * to a shared page. It is done by copying the page to a new address
1260 * and decrementing the shared-page counter for the old page.
1261 *
1262 * Goto-purists beware: the only reason for goto's here is that it results
1263 * in better assembly code.. The "default" path will see no jumps at all.
1264 *
1265 * Note that this routine assumes that the protection checks have been
1266 * done by the caller (the low-level page fault routine in most cases).
1267 * Thus we can safely just mark it writable once we've done any necessary
1268 * COW.
1269 *
1270 * We also mark the page dirty at this point even though the page will
1271 * change only once the write actually happens. This avoids a few races,
1272 * and potentially makes it more efficient.
1273 *
1274 * We hold the mm semaphore and the page_table_lock on entry and exit
1275 * with the page_table_lock released.
1276 */
1277 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
1278 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte)
1279 {
1280 struct page *old_page, *new_page;
1281 unsigned long pfn = pte_pfn(pte);
1282 pte_t entry;
1283
1284 if (unlikely(!pfn_valid(pfn))) {
1285 /*
1286 * This should really halt the system so it can be debugged or
1287 * at least the kernel stops what it's doing before it corrupts
1288 * data, but for the moment just pretend this is OOM.
1289 */
1290 pte_unmap(page_table);
1291 printk(KERN_ERR "do_wp_page: bogus page at address %08lx\n",
1292 address);
1293 spin_unlock(&mm->page_table_lock);
1294 return VM_FAULT_OOM;
1295 }
1296 old_page = pfn_to_page(pfn);
1297
1298 if (!TestSetPageLocked(old_page)) {
1299 int reuse = can_share_swap_page(old_page);
1300 unlock_page(old_page);
1301 if (reuse) {
1302 flush_cache_page(vma, address);
1303 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)),
1304 vma);
1305 ptep_set_access_flags(vma, address, page_table, entry, 1);
1306 update_mmu_cache(vma, address, entry);
1307 pte_unmap(page_table);
1308 spin_unlock(&mm->page_table_lock);
1309 return VM_FAULT_MINOR;
1310 }
1311 }
1312 pte_unmap(page_table);
1313
1314 /*
1315 * Ok, we need to copy. Oh, well..
1316 */
1317 if (!PageReserved(old_page))
1318 page_cache_get(old_page);
1319 spin_unlock(&mm->page_table_lock);
1320
1321 if (unlikely(anon_vma_prepare(vma)))
1322 goto no_new_page;
1323 if (old_page == ZERO_PAGE(address)) {
1324 new_page = alloc_zeroed_user_highpage(vma, address);
1325 if (!new_page)
1326 goto no_new_page;
1327 } else {
1328 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1329 if (!new_page)
1330 goto no_new_page;
1331 copy_user_highpage(new_page, old_page, address);
1332 }
1333 /*
1334 * Re-check the pte - we dropped the lock
1335 */
1336 spin_lock(&mm->page_table_lock);
1337 page_table = pte_offset_map(pmd, address);
1338 if (likely(pte_same(*page_table, pte))) {
1339 if (PageAnon(old_page))
1340 mm->anon_rss--;
1341 if (PageReserved(old_page)) {
1342 ++mm->rss;
1343 acct_update_integrals();
1344 update_mem_hiwater();
1345 } else
1346 page_remove_rmap(old_page);
1347 break_cow(vma, new_page, address, page_table);
1348 lru_cache_add_active(new_page);
1349 page_add_anon_rmap(new_page, vma, address);
1350
1351 /* Free the old page.. */
1352 new_page = old_page;
1353 }
1354 pte_unmap(page_table);
1355 page_cache_release(new_page);
1356 page_cache_release(old_page);
1357 spin_unlock(&mm->page_table_lock);
1358 return VM_FAULT_MINOR;
1359
1360 no_new_page:
1361 page_cache_release(old_page);
1362 return VM_FAULT_OOM;
1363 }
1364
1365 /*
1366 * Helper functions for unmap_mapping_range().
1367 *
1368 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1369 *
1370 * We have to restart searching the prio_tree whenever we drop the lock,
1371 * since the iterator is only valid while the lock is held, and anyway
1372 * a later vma might be split and reinserted earlier while lock dropped.
1373 *
1374 * The list of nonlinear vmas could be handled more efficiently, using
1375 * a placeholder, but handle it in the same way until a need is shown.
1376 * It is important to search the prio_tree before nonlinear list: a vma
1377 * may become nonlinear and be shifted from prio_tree to nonlinear list
1378 * while the lock is dropped; but never shifted from list to prio_tree.
1379 *
1380 * In order to make forward progress despite restarting the search,
1381 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1382 * quickly skip it next time around. Since the prio_tree search only
1383 * shows us those vmas affected by unmapping the range in question, we
1384 * can't efficiently keep all vmas in step with mapping->truncate_count:
1385 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1386 * mapping->truncate_count and vma->vm_truncate_count are protected by
1387 * i_mmap_lock.
1388 *
1389 * In order to make forward progress despite repeatedly restarting some
1390 * large vma, note the break_addr set by unmap_vmas when it breaks out:
1391 * and restart from that address when we reach that vma again. It might
1392 * have been split or merged, shrunk or extended, but never shifted: so
1393 * restart_addr remains valid so long as it remains in the vma's range.
1394 * unmap_mapping_range forces truncate_count to leap over page-aligned
1395 * values so we can save vma's restart_addr in its truncate_count field.
1396 */
1397 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1398
1399 static void reset_vma_truncate_counts(struct address_space *mapping)
1400 {
1401 struct vm_area_struct *vma;
1402 struct prio_tree_iter iter;
1403
1404 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1405 vma->vm_truncate_count = 0;
1406 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1407 vma->vm_truncate_count = 0;
1408 }
1409
1410 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1411 unsigned long start_addr, unsigned long end_addr,
1412 struct zap_details *details)
1413 {
1414 unsigned long restart_addr;
1415 int need_break;
1416
1417 again:
1418 restart_addr = vma->vm_truncate_count;
1419 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1420 start_addr = restart_addr;
1421 if (start_addr >= end_addr) {
1422 /* Top of vma has been split off since last time */
1423 vma->vm_truncate_count = details->truncate_count;
1424 return 0;
1425 }
1426 }
1427
1428 details->break_addr = end_addr;
1429 zap_page_range(vma, start_addr, end_addr - start_addr, details);
1430
1431 /*
1432 * We cannot rely on the break test in unmap_vmas:
1433 * on the one hand, we don't want to restart our loop
1434 * just because that broke out for the page_table_lock;
1435 * on the other hand, it does no test when vma is small.
1436 */
1437 need_break = need_resched() ||
1438 need_lockbreak(details->i_mmap_lock);
1439
1440 if (details->break_addr >= end_addr) {
1441 /* We have now completed this vma: mark it so */
1442 vma->vm_truncate_count = details->truncate_count;
1443 if (!need_break)
1444 return 0;
1445 } else {
1446 /* Note restart_addr in vma's truncate_count field */
1447 vma->vm_truncate_count = details->break_addr;
1448 if (!need_break)
1449 goto again;
1450 }
1451
1452 spin_unlock(details->i_mmap_lock);
1453 cond_resched();
1454 spin_lock(details->i_mmap_lock);
1455 return -EINTR;
1456 }
1457
1458 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1459 struct zap_details *details)
1460 {
1461 struct vm_area_struct *vma;
1462 struct prio_tree_iter iter;
1463 pgoff_t vba, vea, zba, zea;
1464
1465 restart:
1466 vma_prio_tree_foreach(vma, &iter, root,
1467 details->first_index, details->last_index) {
1468 /* Skip quickly over those we have already dealt with */
1469 if (vma->vm_truncate_count == details->truncate_count)
1470 continue;
1471
1472 vba = vma->vm_pgoff;
1473 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1474 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1475 zba = details->first_index;
1476 if (zba < vba)
1477 zba = vba;
1478 zea = details->last_index;
1479 if (zea > vea)
1480 zea = vea;
1481
1482 if (unmap_mapping_range_vma(vma,
1483 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1484 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1485 details) < 0)
1486 goto restart;
1487 }
1488 }
1489
1490 static inline void unmap_mapping_range_list(struct list_head *head,
1491 struct zap_details *details)
1492 {
1493 struct vm_area_struct *vma;
1494
1495 /*
1496 * In nonlinear VMAs there is no correspondence between virtual address
1497 * offset and file offset. So we must perform an exhaustive search
1498 * across *all* the pages in each nonlinear VMA, not just the pages
1499 * whose virtual address lies outside the file truncation point.
1500 */
1501 restart:
1502 list_for_each_entry(vma, head, shared.vm_set.list) {
1503 /* Skip quickly over those we have already dealt with */
1504 if (vma->vm_truncate_count == details->truncate_count)
1505 continue;
1506 details->nonlinear_vma = vma;
1507 if (unmap_mapping_range_vma(vma, vma->vm_start,
1508 vma->vm_end, details) < 0)
1509 goto restart;
1510 }
1511 }
1512
1513 /**
1514 * unmap_mapping_range - unmap the portion of all mmaps
1515 * in the specified address_space corresponding to the specified
1516 * page range in the underlying file.
1517 * @address_space: the address space containing mmaps to be unmapped.
1518 * @holebegin: byte in first page to unmap, relative to the start of
1519 * the underlying file. This will be rounded down to a PAGE_SIZE
1520 * boundary. Note that this is different from vmtruncate(), which
1521 * must keep the partial page. In contrast, we must get rid of
1522 * partial pages.
1523 * @holelen: size of prospective hole in bytes. This will be rounded
1524 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1525 * end of the file.
1526 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1527 * but 0 when invalidating pagecache, don't throw away private data.
1528 */
1529 void unmap_mapping_range(struct address_space *mapping,
1530 loff_t const holebegin, loff_t const holelen, int even_cows)
1531 {
1532 struct zap_details details;
1533 pgoff_t hba = holebegin >> PAGE_SHIFT;
1534 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1535
1536 /* Check for overflow. */
1537 if (sizeof(holelen) > sizeof(hlen)) {
1538 long long holeend =
1539 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1540 if (holeend & ~(long long)ULONG_MAX)
1541 hlen = ULONG_MAX - hba + 1;
1542 }
1543
1544 details.check_mapping = even_cows? NULL: mapping;
1545 details.nonlinear_vma = NULL;
1546 details.first_index = hba;
1547 details.last_index = hba + hlen - 1;
1548 if (details.last_index < details.first_index)
1549 details.last_index = ULONG_MAX;
1550 details.i_mmap_lock = &mapping->i_mmap_lock;
1551
1552 spin_lock(&mapping->i_mmap_lock);
1553
1554 /* serialize i_size write against truncate_count write */
1555 smp_wmb();
1556 /* Protect against page faults, and endless unmapping loops */
1557 mapping->truncate_count++;
1558 /*
1559 * For archs where spin_lock has inclusive semantics like ia64
1560 * this smp_mb() will prevent to read pagetable contents
1561 * before the truncate_count increment is visible to
1562 * other cpus.
1563 */
1564 smp_mb();
1565 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1566 if (mapping->truncate_count == 0)
1567 reset_vma_truncate_counts(mapping);
1568 mapping->truncate_count++;
1569 }
1570 details.truncate_count = mapping->truncate_count;
1571
1572 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1573 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1574 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1575 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1576 spin_unlock(&mapping->i_mmap_lock);
1577 }
1578 EXPORT_SYMBOL(unmap_mapping_range);
1579
1580 /*
1581 * Handle all mappings that got truncated by a "truncate()"
1582 * system call.
1583 *
1584 * NOTE! We have to be ready to update the memory sharing
1585 * between the file and the memory map for a potential last
1586 * incomplete page. Ugly, but necessary.
1587 */
1588 int vmtruncate(struct inode * inode, loff_t offset)
1589 {
1590 struct address_space *mapping = inode->i_mapping;
1591 unsigned long limit;
1592
1593 if (inode->i_size < offset)
1594 goto do_expand;
1595 /*
1596 * truncation of in-use swapfiles is disallowed - it would cause
1597 * subsequent swapout to scribble on the now-freed blocks.
1598 */
1599 if (IS_SWAPFILE(inode))
1600 goto out_busy;
1601 i_size_write(inode, offset);
1602 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1603 truncate_inode_pages(mapping, offset);
1604 goto out_truncate;
1605
1606 do_expand:
1607 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1608 if (limit != RLIM_INFINITY && offset > limit)
1609 goto out_sig;
1610 if (offset > inode->i_sb->s_maxbytes)
1611 goto out_big;
1612 i_size_write(inode, offset);
1613
1614 out_truncate:
1615 if (inode->i_op && inode->i_op->truncate)
1616 inode->i_op->truncate(inode);
1617 return 0;
1618 out_sig:
1619 send_sig(SIGXFSZ, current, 0);
1620 out_big:
1621 return -EFBIG;
1622 out_busy:
1623 return -ETXTBSY;
1624 }
1625
1626 EXPORT_SYMBOL(vmtruncate);
1627
1628 /*
1629 * Primitive swap readahead code. We simply read an aligned block of
1630 * (1 << page_cluster) entries in the swap area. This method is chosen
1631 * because it doesn't cost us any seek time. We also make sure to queue
1632 * the 'original' request together with the readahead ones...
1633 *
1634 * This has been extended to use the NUMA policies from the mm triggering
1635 * the readahead.
1636 *
1637 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1638 */
1639 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1640 {
1641 #ifdef CONFIG_NUMA
1642 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1643 #endif
1644 int i, num;
1645 struct page *new_page;
1646 unsigned long offset;
1647
1648 /*
1649 * Get the number of handles we should do readahead io to.
1650 */
1651 num = valid_swaphandles(entry, &offset);
1652 for (i = 0; i < num; offset++, i++) {
1653 /* Ok, do the async read-ahead now */
1654 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1655 offset), vma, addr);
1656 if (!new_page)
1657 break;
1658 page_cache_release(new_page);
1659 #ifdef CONFIG_NUMA
1660 /*
1661 * Find the next applicable VMA for the NUMA policy.
1662 */
1663 addr += PAGE_SIZE;
1664 if (addr == 0)
1665 vma = NULL;
1666 if (vma) {
1667 if (addr >= vma->vm_end) {
1668 vma = next_vma;
1669 next_vma = vma ? vma->vm_next : NULL;
1670 }
1671 if (vma && addr < vma->vm_start)
1672 vma = NULL;
1673 } else {
1674 if (next_vma && addr >= next_vma->vm_start) {
1675 vma = next_vma;
1676 next_vma = vma->vm_next;
1677 }
1678 }
1679 #endif
1680 }
1681 lru_add_drain(); /* Push any new pages onto the LRU now */
1682 }
1683
1684 /*
1685 * We hold the mm semaphore and the page_table_lock on entry and
1686 * should release the pagetable lock on exit..
1687 */
1688 static int do_swap_page(struct mm_struct * mm,
1689 struct vm_area_struct * vma, unsigned long address,
1690 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access)
1691 {
1692 struct page *page;
1693 swp_entry_t entry = pte_to_swp_entry(orig_pte);
1694 pte_t pte;
1695 int ret = VM_FAULT_MINOR;
1696
1697 pte_unmap(page_table);
1698 spin_unlock(&mm->page_table_lock);
1699 page = lookup_swap_cache(entry);
1700 if (!page) {
1701 swapin_readahead(entry, address, vma);
1702 page = read_swap_cache_async(entry, vma, address);
1703 if (!page) {
1704 /*
1705 * Back out if somebody else faulted in this pte while
1706 * we released the page table lock.
1707 */
1708 spin_lock(&mm->page_table_lock);
1709 page_table = pte_offset_map(pmd, address);
1710 if (likely(pte_same(*page_table, orig_pte)))
1711 ret = VM_FAULT_OOM;
1712 else
1713 ret = VM_FAULT_MINOR;
1714 pte_unmap(page_table);
1715 spin_unlock(&mm->page_table_lock);
1716 goto out;
1717 }
1718
1719 /* Had to read the page from swap area: Major fault */
1720 ret = VM_FAULT_MAJOR;
1721 inc_page_state(pgmajfault);
1722 grab_swap_token();
1723 }
1724
1725 mark_page_accessed(page);
1726 lock_page(page);
1727
1728 /*
1729 * Back out if somebody else faulted in this pte while we
1730 * released the page table lock.
1731 */
1732 spin_lock(&mm->page_table_lock);
1733 page_table = pte_offset_map(pmd, address);
1734 if (unlikely(!pte_same(*page_table, orig_pte))) {
1735 pte_unmap(page_table);
1736 spin_unlock(&mm->page_table_lock);
1737 unlock_page(page);
1738 page_cache_release(page);
1739 ret = VM_FAULT_MINOR;
1740 goto out;
1741 }
1742
1743 /* The page isn't present yet, go ahead with the fault. */
1744
1745 swap_free(entry);
1746 if (vm_swap_full())
1747 remove_exclusive_swap_page(page);
1748
1749 mm->rss++;
1750 acct_update_integrals();
1751 update_mem_hiwater();
1752
1753 pte = mk_pte(page, vma->vm_page_prot);
1754 if (write_access && can_share_swap_page(page)) {
1755 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1756 write_access = 0;
1757 }
1758 unlock_page(page);
1759
1760 flush_icache_page(vma, page);
1761 set_pte(page_table, pte);
1762 page_add_anon_rmap(page, vma, address);
1763
1764 if (write_access) {
1765 if (do_wp_page(mm, vma, address,
1766 page_table, pmd, pte) == VM_FAULT_OOM)
1767 ret = VM_FAULT_OOM;
1768 goto out;
1769 }
1770
1771 /* No need to invalidate - it was non-present before */
1772 update_mmu_cache(vma, address, pte);
1773 pte_unmap(page_table);
1774 spin_unlock(&mm->page_table_lock);
1775 out:
1776 return ret;
1777 }
1778
1779 /*
1780 * We are called with the MM semaphore and page_table_lock
1781 * spinlock held to protect against concurrent faults in
1782 * multithreaded programs.
1783 */
1784 static int
1785 do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1786 pte_t *page_table, pmd_t *pmd, int write_access,
1787 unsigned long addr)
1788 {
1789 pte_t entry;
1790 struct page * page = ZERO_PAGE(addr);
1791
1792 /* Read-only mapping of ZERO_PAGE. */
1793 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
1794
1795 /* ..except if it's a write access */
1796 if (write_access) {
1797 /* Allocate our own private page. */
1798 pte_unmap(page_table);
1799 spin_unlock(&mm->page_table_lock);
1800
1801 if (unlikely(anon_vma_prepare(vma)))
1802 goto no_mem;
1803 page = alloc_zeroed_user_highpage(vma, addr);
1804 if (!page)
1805 goto no_mem;
1806
1807 spin_lock(&mm->page_table_lock);
1808 page_table = pte_offset_map(pmd, addr);
1809
1810 if (!pte_none(*page_table)) {
1811 pte_unmap(page_table);
1812 page_cache_release(page);
1813 spin_unlock(&mm->page_table_lock);
1814 goto out;
1815 }
1816 mm->rss++;
1817 acct_update_integrals();
1818 update_mem_hiwater();
1819 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page,
1820 vma->vm_page_prot)),
1821 vma);
1822 lru_cache_add_active(page);
1823 SetPageReferenced(page);
1824 page_add_anon_rmap(page, vma, addr);
1825 }
1826
1827 set_pte(page_table, entry);
1828 pte_unmap(page_table);
1829
1830 /* No need to invalidate - it was non-present before */
1831 update_mmu_cache(vma, addr, entry);
1832 spin_unlock(&mm->page_table_lock);
1833 out:
1834 return VM_FAULT_MINOR;
1835 no_mem:
1836 return VM_FAULT_OOM;
1837 }
1838
1839 /*
1840 * do_no_page() tries to create a new page mapping. It aggressively
1841 * tries to share with existing pages, but makes a separate copy if
1842 * the "write_access" parameter is true in order to avoid the next
1843 * page fault.
1844 *
1845 * As this is called only for pages that do not currently exist, we
1846 * do not need to flush old virtual caches or the TLB.
1847 *
1848 * This is called with the MM semaphore held and the page table
1849 * spinlock held. Exit with the spinlock released.
1850 */
1851 static int
1852 do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1853 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
1854 {
1855 struct page * new_page;
1856 struct address_space *mapping = NULL;
1857 pte_t entry;
1858 unsigned int sequence = 0;
1859 int ret = VM_FAULT_MINOR;
1860 int anon = 0;
1861
1862 if (!vma->vm_ops || !vma->vm_ops->nopage)
1863 return do_anonymous_page(mm, vma, page_table,
1864 pmd, write_access, address);
1865 pte_unmap(page_table);
1866 spin_unlock(&mm->page_table_lock);
1867
1868 if (vma->vm_file) {
1869 mapping = vma->vm_file->f_mapping;
1870 sequence = mapping->truncate_count;
1871 smp_rmb(); /* serializes i_size against truncate_count */
1872 }
1873 retry:
1874 cond_resched();
1875 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1876 /*
1877 * No smp_rmb is needed here as long as there's a full
1878 * spin_lock/unlock sequence inside the ->nopage callback
1879 * (for the pagecache lookup) that acts as an implicit
1880 * smp_mb() and prevents the i_size read to happen
1881 * after the next truncate_count read.
1882 */
1883
1884 /* no page was available -- either SIGBUS or OOM */
1885 if (new_page == NOPAGE_SIGBUS)
1886 return VM_FAULT_SIGBUS;
1887 if (new_page == NOPAGE_OOM)
1888 return VM_FAULT_OOM;
1889
1890 /*
1891 * Should we do an early C-O-W break?
1892 */
1893 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1894 struct page *page;
1895
1896 if (unlikely(anon_vma_prepare(vma)))
1897 goto oom;
1898 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1899 if (!page)
1900 goto oom;
1901 copy_user_highpage(page, new_page, address);
1902 page_cache_release(new_page);
1903 new_page = page;
1904 anon = 1;
1905 }
1906
1907 spin_lock(&mm->page_table_lock);
1908 /*
1909 * For a file-backed vma, someone could have truncated or otherwise
1910 * invalidated this page. If unmap_mapping_range got called,
1911 * retry getting the page.
1912 */
1913 if (mapping && unlikely(sequence != mapping->truncate_count)) {
1914 sequence = mapping->truncate_count;
1915 spin_unlock(&mm->page_table_lock);
1916 page_cache_release(new_page);
1917 goto retry;
1918 }
1919 page_table = pte_offset_map(pmd, address);
1920
1921 /*
1922 * This silly early PAGE_DIRTY setting removes a race
1923 * due to the bad i386 page protection. But it's valid
1924 * for other architectures too.
1925 *
1926 * Note that if write_access is true, we either now have
1927 * an exclusive copy of the page, or this is a shared mapping,
1928 * so we can make it writable and dirty to avoid having to
1929 * handle that later.
1930 */
1931 /* Only go through if we didn't race with anybody else... */
1932 if (pte_none(*page_table)) {
1933 if (!PageReserved(new_page))
1934 ++mm->rss;
1935 acct_update_integrals();
1936 update_mem_hiwater();
1937
1938 flush_icache_page(vma, new_page);
1939 entry = mk_pte(new_page, vma->vm_page_prot);
1940 if (write_access)
1941 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1942 set_pte(page_table, entry);
1943 if (anon) {
1944 lru_cache_add_active(new_page);
1945 page_add_anon_rmap(new_page, vma, address);
1946 } else
1947 page_add_file_rmap(new_page);
1948 pte_unmap(page_table);
1949 } else {
1950 /* One of our sibling threads was faster, back out. */
1951 pte_unmap(page_table);
1952 page_cache_release(new_page);
1953 spin_unlock(&mm->page_table_lock);
1954 goto out;
1955 }
1956
1957 /* no need to invalidate: a not-present page shouldn't be cached */
1958 update_mmu_cache(vma, address, entry);
1959 spin_unlock(&mm->page_table_lock);
1960 out:
1961 return ret;
1962 oom:
1963 page_cache_release(new_page);
1964 ret = VM_FAULT_OOM;
1965 goto out;
1966 }
1967
1968 /*
1969 * Fault of a previously existing named mapping. Repopulate the pte
1970 * from the encoded file_pte if possible. This enables swappable
1971 * nonlinear vmas.
1972 */
1973 static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma,
1974 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
1975 {
1976 unsigned long pgoff;
1977 int err;
1978
1979 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
1980 /*
1981 * Fall back to the linear mapping if the fs does not support
1982 * ->populate:
1983 */
1984 if (!vma->vm_ops || !vma->vm_ops->populate ||
1985 (write_access && !(vma->vm_flags & VM_SHARED))) {
1986 pte_clear(pte);
1987 return do_no_page(mm, vma, address, write_access, pte, pmd);
1988 }
1989
1990 pgoff = pte_to_pgoff(*pte);
1991
1992 pte_unmap(pte);
1993 spin_unlock(&mm->page_table_lock);
1994
1995 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
1996 if (err == -ENOMEM)
1997 return VM_FAULT_OOM;
1998 if (err)
1999 return VM_FAULT_SIGBUS;
2000 return VM_FAULT_MAJOR;
2001 }
2002
2003 /*
2004 * These routines also need to handle stuff like marking pages dirty
2005 * and/or accessed for architectures that don't do it in hardware (most
2006 * RISC architectures). The early dirtying is also good on the i386.
2007 *
2008 * There is also a hook called "update_mmu_cache()" that architectures
2009 * with external mmu caches can use to update those (ie the Sparc or
2010 * PowerPC hashed page tables that act as extended TLBs).
2011 *
2012 * Note the "page_table_lock". It is to protect against kswapd removing
2013 * pages from under us. Note that kswapd only ever _removes_ pages, never
2014 * adds them. As such, once we have noticed that the page is not present,
2015 * we can drop the lock early.
2016 *
2017 * The adding of pages is protected by the MM semaphore (which we hold),
2018 * so we don't need to worry about a page being suddenly been added into
2019 * our VM.
2020 *
2021 * We enter with the pagetable spinlock held, we are supposed to
2022 * release it when done.
2023 */
2024 static inline int handle_pte_fault(struct mm_struct *mm,
2025 struct vm_area_struct * vma, unsigned long address,
2026 int write_access, pte_t *pte, pmd_t *pmd)
2027 {
2028 pte_t entry;
2029
2030 entry = *pte;
2031 if (!pte_present(entry)) {
2032 /*
2033 * If it truly wasn't present, we know that kswapd
2034 * and the PTE updates will not touch it later. So
2035 * drop the lock.
2036 */
2037 if (pte_none(entry))
2038 return do_no_page(mm, vma, address, write_access, pte, pmd);
2039 if (pte_file(entry))
2040 return do_file_page(mm, vma, address, write_access, pte, pmd);
2041 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
2042 }
2043
2044 if (write_access) {
2045 if (!pte_write(entry))
2046 return do_wp_page(mm, vma, address, pte, pmd, entry);
2047
2048 entry = pte_mkdirty(entry);
2049 }
2050 entry = pte_mkyoung(entry);
2051 ptep_set_access_flags(vma, address, pte, entry, write_access);
2052 update_mmu_cache(vma, address, entry);
2053 pte_unmap(pte);
2054 spin_unlock(&mm->page_table_lock);
2055 return VM_FAULT_MINOR;
2056 }
2057
2058 /*
2059 * By the time we get here, we already hold the mm semaphore
2060 */
2061 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma,
2062 unsigned long address, int write_access)
2063 {
2064 pgd_t *pgd;
2065 pud_t *pud;
2066 pmd_t *pmd;
2067 pte_t *pte;
2068
2069 __set_current_state(TASK_RUNNING);
2070
2071 inc_page_state(pgfault);
2072
2073 if (is_vm_hugetlb_page(vma))
2074 return VM_FAULT_SIGBUS; /* mapping truncation does this. */
2075
2076 /*
2077 * We need the page table lock to synchronize with kswapd
2078 * and the SMP-safe atomic PTE updates.
2079 */
2080 pgd = pgd_offset(mm, address);
2081 spin_lock(&mm->page_table_lock);
2082
2083 pud = pud_alloc(mm, pgd, address);
2084 if (!pud)
2085 goto oom;
2086
2087 pmd = pmd_alloc(mm, pud, address);
2088 if (!pmd)
2089 goto oom;
2090
2091 pte = pte_alloc_map(mm, pmd, address);
2092 if (!pte)
2093 goto oom;
2094
2095 return handle_pte_fault(mm, vma, address, write_access, pte, pmd);
2096
2097 oom:
2098 spin_unlock(&mm->page_table_lock);
2099 return VM_FAULT_OOM;
2100 }
2101
2102 #ifndef __ARCH_HAS_4LEVEL_HACK
2103 /*
2104 * Allocate page upper directory.
2105 *
2106 * We've already handled the fast-path in-line, and we own the
2107 * page table lock.
2108 *
2109 * On a two-level or three-level page table, this ends up actually being
2110 * entirely optimized away.
2111 */
2112 pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2113 {
2114 pud_t *new;
2115
2116 spin_unlock(&mm->page_table_lock);
2117 new = pud_alloc_one(mm, address);
2118 spin_lock(&mm->page_table_lock);
2119 if (!new)
2120 return NULL;
2121
2122 /*
2123 * Because we dropped the lock, we should re-check the
2124 * entry, as somebody else could have populated it..
2125 */
2126 if (pgd_present(*pgd)) {
2127 pud_free(new);
2128 goto out;
2129 }
2130 pgd_populate(mm, pgd, new);
2131 out:
2132 return pud_offset(pgd, address);
2133 }
2134
2135 /*
2136 * Allocate page middle directory.
2137 *
2138 * We've already handled the fast-path in-line, and we own the
2139 * page table lock.
2140 *
2141 * On a two-level page table, this ends up actually being entirely
2142 * optimized away.
2143 */
2144 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2145 {
2146 pmd_t *new;
2147
2148 spin_unlock(&mm->page_table_lock);
2149 new = pmd_alloc_one(mm, address);
2150 spin_lock(&mm->page_table_lock);
2151 if (!new)
2152 return NULL;
2153
2154 /*
2155 * Because we dropped the lock, we should re-check the
2156 * entry, as somebody else could have populated it..
2157 */
2158 if (pud_present(*pud)) {
2159 pmd_free(new);
2160 goto out;
2161 }
2162 pud_populate(mm, pud, new);
2163 out:
2164 return pmd_offset(pud, address);
2165 }
2166 #else
2167 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2168 {
2169 pmd_t *new;
2170
2171 spin_unlock(&mm->page_table_lock);
2172 new = pmd_alloc_one(mm, address);
2173 spin_lock(&mm->page_table_lock);
2174 if (!new)
2175 return NULL;
2176
2177 /*
2178 * Because we dropped the lock, we should re-check the
2179 * entry, as somebody else could have populated it..
2180 */
2181 if (pgd_present(*pud)) {
2182 pmd_free(new);
2183 goto out;
2184 }
2185 pgd_populate(mm, pud, new);
2186 out:
2187 return pmd_offset(pud, address);
2188 }
2189 #endif
2190
2191 int make_pages_present(unsigned long addr, unsigned long end)
2192 {
2193 int ret, len, write;
2194 struct vm_area_struct * vma;
2195
2196 vma = find_vma(current->mm, addr);
2197 if (!vma)
2198 return -1;
2199 write = (vma->vm_flags & VM_WRITE) != 0;
2200 if (addr >= end)
2201 BUG();
2202 if (end > vma->vm_end)
2203 BUG();
2204 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2205 ret = get_user_pages(current, current->mm, addr,
2206 len, write, 0, NULL, NULL);
2207 if (ret < 0)
2208 return ret;
2209 return ret == len ? 0 : -1;
2210 }
2211
2212 /*
2213 * Map a vmalloc()-space virtual address to the physical page.
2214 */
2215 struct page * vmalloc_to_page(void * vmalloc_addr)
2216 {
2217 unsigned long addr = (unsigned long) vmalloc_addr;
2218 struct page *page = NULL;
2219 pgd_t *pgd = pgd_offset_k(addr);
2220 pud_t *pud;
2221 pmd_t *pmd;
2222 pte_t *ptep, pte;
2223
2224 if (!pgd_none(*pgd)) {
2225 pud = pud_offset(pgd, addr);
2226 if (!pud_none(*pud)) {
2227 pmd = pmd_offset(pud, addr);
2228 if (!pmd_none(*pmd)) {
2229 ptep = pte_offset_map(pmd, addr);
2230 pte = *ptep;
2231 if (pte_present(pte))
2232 page = pte_page(pte);
2233 pte_unmap(ptep);
2234 }
2235 }
2236 }
2237 return page;
2238 }
2239
2240 EXPORT_SYMBOL(vmalloc_to_page);
2241
2242 /*
2243 * Map a vmalloc()-space virtual address to the physical page frame number.
2244 */
2245 unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2246 {
2247 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2248 }
2249
2250 EXPORT_SYMBOL(vmalloc_to_pfn);
2251
2252 /*
2253 * update_mem_hiwater
2254 * - update per process rss and vm high water data
2255 */
2256 void update_mem_hiwater(void)
2257 {
2258 struct task_struct *tsk = current;
2259
2260 if (tsk->mm) {
2261 if (tsk->mm->hiwater_rss < tsk->mm->rss)
2262 tsk->mm->hiwater_rss = tsk->mm->rss;
2263 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
2264 tsk->mm->hiwater_vm = tsk->mm->total_vm;
2265 }
2266 }
2267
2268 #if !defined(__HAVE_ARCH_GATE_AREA)
2269
2270 #if defined(AT_SYSINFO_EHDR)
2271 struct vm_area_struct gate_vma;
2272
2273 static int __init gate_vma_init(void)
2274 {
2275 gate_vma.vm_mm = NULL;
2276 gate_vma.vm_start = FIXADDR_USER_START;
2277 gate_vma.vm_end = FIXADDR_USER_END;
2278 gate_vma.vm_page_prot = PAGE_READONLY;
2279 gate_vma.vm_flags = 0;
2280 return 0;
2281 }
2282 __initcall(gate_vma_init);
2283 #endif
2284
2285 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2286 {
2287 #ifdef AT_SYSINFO_EHDR
2288 return &gate_vma;
2289 #else
2290 return NULL;
2291 #endif
2292 }
2293
2294 int in_gate_area_no_task(unsigned long addr)
2295 {
2296 #ifdef AT_SYSINFO_EHDR
2297 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2298 return 1;
2299 #endif
2300 return 0;
2301 }
2302
2303 #endif /* __HAVE_ARCH_GATE_AREA */
2304
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