debuggers.hg

view linux-2.6-xen-sparse/mm/memory.c @ 6641:f27205ea60ef

merge?
author cl349@firebug.cl.cam.ac.uk
date Sat Sep 03 16:58:50 2005 +0000 (2005-09-03)
parents dd668f7527cb 7c2afbad0188
children 29808fef9148 b6c98fe62e1a
line source
1 /*
2 * linux/mm/memory.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
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 */
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 */
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 */
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 */
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>
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>
58 #include <linux/swapops.h>
59 #include <linux/elf.h>
61 #ifndef CONFIG_DISCONTIGMEM
62 /* use the per-pgdat data instead for discontigmem - mbligh */
63 unsigned long max_mapnr;
64 struct page *mem_map;
66 EXPORT_SYMBOL(max_mapnr);
67 EXPORT_SYMBOL(mem_map);
68 #endif
70 unsigned 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 */
78 void * high_memory;
79 unsigned long vmalloc_earlyreserve;
81 EXPORT_SYMBOL(num_physpages);
82 EXPORT_SYMBOL(high_memory);
83 EXPORT_SYMBOL(vmalloc_earlyreserve);
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 */
91 void pgd_clear_bad(pgd_t *pgd)
92 {
93 pgd_ERROR(*pgd);
94 pgd_clear(pgd);
95 }
97 void pud_clear_bad(pud_t *pud)
98 {
99 pud_ERROR(*pud);
100 pud_clear(pud);
101 }
103 void pmd_clear_bad(pmd_t *pmd)
104 {
105 pmd_ERROR(*pmd);
106 pmd_clear(pmd);
107 }
109 /*
110 * Note: this doesn't free the actual pages themselves. That
111 * has been handled earlier when unmapping all the memory regions.
112 */
113 static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
114 {
115 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--;
120 }
122 static 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)
125 {
126 pmd_t *pmd;
127 unsigned long next;
128 unsigned long start;
130 start = addr;
131 pmd = pmd_offset(pud, addr);
132 do {
133 next = pmd_addr_end(addr, end);
134 if (pmd_none_or_clear_bad(pmd))
135 continue;
136 free_pte_range(tlb, pmd);
137 } while (pmd++, addr = next, addr != end);
139 start &= PUD_MASK;
140 if (start < floor)
141 return;
142 if (ceiling) {
143 ceiling &= PUD_MASK;
144 if (!ceiling)
145 return;
146 }
147 if (end - 1 > ceiling - 1)
148 return;
150 pmd = pmd_offset(pud, start);
151 pud_clear(pud);
152 pmd_free_tlb(tlb, pmd);
153 }
155 static 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)
158 {
159 pud_t *pud;
160 unsigned long next;
161 unsigned long start;
163 start = addr;
164 pud = pud_offset(pgd, addr);
165 do {
166 next = pud_addr_end(addr, end);
167 if (pud_none_or_clear_bad(pud))
168 continue;
169 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
170 } while (pud++, addr = next, addr != end);
172 start &= PGDIR_MASK;
173 if (start < floor)
174 return;
175 if (ceiling) {
176 ceiling &= PGDIR_MASK;
177 if (!ceiling)
178 return;
179 }
180 if (end - 1 > ceiling - 1)
181 return;
183 pud = pud_offset(pgd, start);
184 pgd_clear(pgd);
185 pud_free_tlb(tlb, pud);
186 }
188 /*
189 * This function frees user-level page tables of a process.
190 *
191 * Must be called with pagetable lock held.
192 */
193 void free_pgd_range(struct mmu_gather **tlb,
194 unsigned long addr, unsigned long end,
195 unsigned long floor, unsigned long ceiling)
196 {
197 pgd_t *pgd;
198 unsigned long next;
199 unsigned long start;
201 /*
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 */
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;
243 start = addr;
244 pgd = pgd_offset((*tlb)->mm, addr);
245 do {
246 next = pgd_addr_end(addr, end);
247 if (pgd_none_or_clear_bad(pgd))
248 continue;
249 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
250 } while (pgd++, addr = next, addr != end);
252 if (!tlb_is_full_mm(*tlb))
253 flush_tlb_pgtables((*tlb)->mm, start, end);
254 }
256 void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
257 unsigned long floor, unsigned long ceiling)
258 {
259 while (vma) {
260 struct vm_area_struct *next = vma->vm_next;
261 unsigned long addr = vma->vm_start;
263 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
264 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
265 floor, next? next->vm_start: ceiling);
266 } 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 }
279 vma = next;
280 }
281 }
283 pte_t fastcall *pte_alloc_map(struct mm_struct *mm, pmd_t *pmd,
284 unsigned long address)
285 {
286 if (!pmd_present(*pmd)) {
287 struct page *new;
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 }
306 out:
307 return pte_offset_map(pmd, address);
308 }
310 pte_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;
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;
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 }
331 out:
332 return pte_offset_kernel(pmd, address);
333 }
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 */
344 static inline void
345 copy_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;
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 }
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);
378 if (!page || PageReserved(page)) {
379 set_pte_at(dst_mm, addr, dst_pte, pte);
380 return;
381 }
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 }
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 }
407 static 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;
415 again:
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);
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);
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 }
449 static 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;
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 }
471 static 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;
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 }
493 int 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;
501 if (is_vm_hugetlb_page(vma))
502 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
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 }
517 static 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;
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 }
587 static 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;
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 }
603 static 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;
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 }
619 static 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;
626 if (details && !details->check_mapping && !details->nonlinear_vma)
627 details = NULL;
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 }
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
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 *
658 * Returns the end address of the unmapping (restart addr if interrupted).
659 *
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 */
675 unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
676 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;
683 unsigned long start = start_addr;
684 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
685 int fullmm = tlb_is_full_mm(*tlbp);
687 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
688 unsigned long end;
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;
697 if (vma->vm_flags & VM_ACCOUNT)
698 *nr_accounted += (end - start) >> PAGE_SHIFT;
700 while (start != end) {
701 unsigned long block;
703 if (!tlb_start_valid) {
704 tlb_start = start;
705 tlb_start_valid = 1;
706 }
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 }
717 start += block;
718 zap_bytes -= block;
719 if ((long)zap_bytes > 0)
720 continue;
722 tlb_finish_mmu(*tlbp, tlb_start, start);
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);
730 goto out;
731 }
732 spin_unlock(&mm->page_table_lock);
733 cond_resched();
734 spin_lock(&mm->page_table_lock);
735 }
737 *tlbp = tlb_gather_mmu(mm, fullmm);
738 tlb_start_valid = 0;
739 zap_bytes = ZAP_BLOCK_SIZE;
740 }
741 }
742 out:
743 return start; /* which is now the end (or restart) address */
744 }
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 */
753 unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
754 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;
761 if (is_vm_hugetlb_page(vma)) {
762 zap_hugepage_range(vma, address, size);
763 return end;
764 }
766 lru_add_drain();
767 spin_lock(&mm->page_table_lock);
768 tlb = tlb_gather_mmu(mm, 0);
769 end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
770 tlb_finish_mmu(tlb, address, end);
771 spin_unlock(&mm->page_table_lock);
772 return end;
773 }
775 /*
776 * Do a quick page-table lookup for a single page.
777 * mm->page_table_lock must be held.
778 */
779 static struct page *
780 __follow_page(struct mm_struct *mm, unsigned long address, int read, int write)
781 {
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;
789 page = follow_huge_addr(mm, address, write);
790 if (! IS_ERR(page))
791 return page;
793 pgd = pgd_offset(mm, address);
794 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
795 goto out;
797 pud = pud_offset(pgd, address);
798 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
799 goto out;
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);
807 ptep = pte_offset_map(pmd, address);
808 if (!ptep)
809 goto out;
811 pte = *ptep;
812 pte_unmap(ptep);
813 if (pte_present(pte)) {
814 if (write && !pte_write(pte))
815 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);
821 if (write && !pte_dirty(pte) && !PageDirty(page))
822 set_page_dirty(page);
823 mark_page_accessed(page);
824 return page;
825 }
826 }
828 out:
829 return NULL;
830 }
832 struct page *
833 follow_page(struct mm_struct *mm, unsigned long address, int write)
834 {
835 return __follow_page(mm, address, /*read*/0, write);
836 }
838 int
839 check_user_page_readable(struct mm_struct *mm, unsigned long address)
840 {
841 return __follow_page(mm, address, /*read*/1, /*write*/0) != NULL;
842 }
844 EXPORT_SYMBOL(check_user_page_readable);
846 /*
847 * Given a physical address, is there a useful struct page pointing to
848 * it? This may become more complex in the future if we start dealing
849 * with IO-aperture pages for direct-IO.
850 */
852 static inline struct page *get_page_map(struct page *page)
853 {
854 if (!pfn_valid(page_to_pfn(page)))
855 return NULL;
856 return page;
857 }
860 static inline int
861 untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
862 unsigned long address)
863 {
864 pgd_t *pgd;
865 pud_t *pud;
866 pmd_t *pmd;
868 /* Check if the vma is for an anonymous mapping. */
869 if (vma->vm_ops && vma->vm_ops->nopage)
870 return 0;
872 /* Check if page directory entry exists. */
873 pgd = pgd_offset(mm, address);
874 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
875 return 1;
877 pud = pud_offset(pgd, address);
878 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
879 return 1;
881 /* Check if page middle directory entry exists. */
882 pmd = pmd_offset(pud, address);
883 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
884 return 1;
886 /* There is a pte slot for 'address' in 'mm'. */
887 return 0;
888 }
891 int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
892 unsigned long start, int len, int write, int force,
893 struct page **pages, struct vm_area_struct **vmas)
894 {
895 int i;
896 unsigned int flags;
898 /*
899 * Require read or write permissions.
900 * If 'force' is set, we only require the "MAY" flags.
901 */
902 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
903 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
904 i = 0;
906 do {
907 struct vm_area_struct * vma;
909 vma = find_extend_vma(mm, start);
910 if (!vma && in_gate_area(tsk, start)) {
911 unsigned long pg = start & PAGE_MASK;
912 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
913 pgd_t *pgd;
914 pud_t *pud;
915 pmd_t *pmd;
916 pte_t *pte;
917 if (write) /* user gate pages are read-only */
918 return i ? : -EFAULT;
919 if (pg > TASK_SIZE)
920 pgd = pgd_offset_k(pg);
921 else
922 pgd = pgd_offset_gate(mm, pg);
923 BUG_ON(pgd_none(*pgd));
924 pud = pud_offset(pgd, pg);
925 BUG_ON(pud_none(*pud));
926 pmd = pmd_offset(pud, pg);
927 BUG_ON(pmd_none(*pmd));
928 pte = pte_offset_map(pmd, pg);
929 BUG_ON(pte_none(*pte));
930 if (pages) {
931 pages[i] = pte_page(*pte);
932 get_page(pages[i]);
933 }
934 pte_unmap(pte);
935 if (vmas)
936 vmas[i] = gate_vma;
937 i++;
938 start += PAGE_SIZE;
939 len--;
940 continue;
941 }
943 if (vma && (vma->vm_flags & VM_FOREIGN))
944 {
945 struct page **map = vma->vm_private_data;
946 int offset = (start - vma->vm_start) >> PAGE_SHIFT;
948 if (map[offset] != NULL) {
949 if (pages) {
950 pages[i] = map[offset];
951 }
952 if (vmas)
953 vmas[i] = vma;
954 i++;
955 start += PAGE_SIZE;
956 len--;
957 printk(KERN_ALERT "HIT 0x%lx\n", start);
958 continue;
959 }
960 else printk(KERN_ALERT "MISS 0x%lx\n", start);
961 }
963 if (!vma || (vma->vm_flags & VM_IO)
964 || !(flags & vma->vm_flags))
965 return i ? : -EFAULT;
967 if (is_vm_hugetlb_page(vma)) {
968 i = follow_hugetlb_page(mm, vma, pages, vmas,
969 &start, &len, i);
970 continue;
971 }
972 spin_lock(&mm->page_table_lock);
973 do {
974 struct page *map;
975 int lookup_write = write;
977 cond_resched_lock(&mm->page_table_lock);
978 while (!(map = follow_page(mm, start, lookup_write))) {
979 /*
980 * Shortcut for anonymous pages. We don't want
981 * to force the creation of pages tables for
982 * insanly big anonymously mapped areas that
983 * nobody touched so far. This is important
984 * for doing a core dump for these mappings.
985 */
986 if (!lookup_write &&
987 untouched_anonymous_page(mm,vma,start)) {
988 map = ZERO_PAGE(start);
989 break;
990 }
991 spin_unlock(&mm->page_table_lock);
992 switch (handle_mm_fault(mm,vma,start,write)) {
993 case VM_FAULT_MINOR:
994 tsk->min_flt++;
995 break;
996 case VM_FAULT_MAJOR:
997 tsk->maj_flt++;
998 break;
999 case VM_FAULT_SIGBUS:
1000 return i ? i : -EFAULT;
1001 case VM_FAULT_OOM:
1002 return i ? i : -ENOMEM;
1003 default:
1004 BUG();
1006 /*
1007 * Now that we have performed a write fault
1008 * and surely no longer have a shared page we
1009 * shouldn't write, we shouldn't ignore an
1010 * unwritable page in the page table if
1011 * we are forcing write access.
1012 */
1013 lookup_write = write && !force;
1014 spin_lock(&mm->page_table_lock);
1016 if (pages) {
1017 pages[i] = get_page_map(map);
1018 if (!pages[i]) {
1019 spin_unlock(&mm->page_table_lock);
1020 while (i--)
1021 page_cache_release(pages[i]);
1022 i = -EFAULT;
1023 goto out;
1025 flush_dcache_page(pages[i]);
1026 if (!PageReserved(pages[i]))
1027 page_cache_get(pages[i]);
1029 if (vmas)
1030 vmas[i] = vma;
1031 i++;
1032 start += PAGE_SIZE;
1033 len--;
1034 } while(len && start < vma->vm_end);
1035 spin_unlock(&mm->page_table_lock);
1036 } while(len);
1037 out:
1038 return i;
1041 EXPORT_SYMBOL(get_user_pages);
1043 static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1044 unsigned long addr, unsigned long end, pgprot_t prot)
1046 pte_t *pte;
1048 pte = pte_alloc_map(mm, pmd, addr);
1049 if (!pte)
1050 return -ENOMEM;
1051 do {
1052 pte_t zero_pte = pte_wrprotect(mk_pte(ZERO_PAGE(addr), prot));
1053 BUG_ON(!pte_none(*pte));
1054 set_pte_at(mm, addr, pte, zero_pte);
1055 } while (pte++, addr += PAGE_SIZE, addr != end);
1056 pte_unmap(pte - 1);
1057 return 0;
1060 static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1061 unsigned long addr, unsigned long end, pgprot_t prot)
1063 pmd_t *pmd;
1064 unsigned long next;
1066 pmd = pmd_alloc(mm, pud, addr);
1067 if (!pmd)
1068 return -ENOMEM;
1069 do {
1070 next = pmd_addr_end(addr, end);
1071 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1072 return -ENOMEM;
1073 } while (pmd++, addr = next, addr != end);
1074 return 0;
1077 static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1078 unsigned long addr, unsigned long end, pgprot_t prot)
1080 pud_t *pud;
1081 unsigned long next;
1083 pud = pud_alloc(mm, pgd, addr);
1084 if (!pud)
1085 return -ENOMEM;
1086 do {
1087 next = pud_addr_end(addr, end);
1088 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1089 return -ENOMEM;
1090 } while (pud++, addr = next, addr != end);
1091 return 0;
1094 int zeromap_page_range(struct vm_area_struct *vma,
1095 unsigned long addr, unsigned long size, pgprot_t prot)
1097 pgd_t *pgd;
1098 unsigned long next;
1099 unsigned long end = addr + size;
1100 struct mm_struct *mm = vma->vm_mm;
1101 int err;
1103 BUG_ON(addr >= end);
1104 pgd = pgd_offset(mm, addr);
1105 flush_cache_range(vma, addr, end);
1106 spin_lock(&mm->page_table_lock);
1107 do {
1108 next = pgd_addr_end(addr, end);
1109 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1110 if (err)
1111 break;
1112 } while (pgd++, addr = next, addr != end);
1113 spin_unlock(&mm->page_table_lock);
1114 return err;
1117 /*
1118 * maps a range of physical memory into the requested pages. the old
1119 * mappings are removed. any references to nonexistent pages results
1120 * in null mappings (currently treated as "copy-on-access")
1121 */
1122 static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1123 unsigned long addr, unsigned long end,
1124 unsigned long pfn, pgprot_t prot)
1126 pte_t *pte;
1128 pte = pte_alloc_map(mm, pmd, addr);
1129 if (!pte)
1130 return -ENOMEM;
1131 do {
1132 BUG_ON(!pte_none(*pte));
1133 if (!pfn_valid(pfn) || PageReserved(pfn_to_page(pfn)))
1134 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
1135 pfn++;
1136 } while (pte++, addr += PAGE_SIZE, addr != end);
1137 pte_unmap(pte - 1);
1138 return 0;
1141 static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1142 unsigned long addr, unsigned long end,
1143 unsigned long pfn, pgprot_t prot)
1145 pmd_t *pmd;
1146 unsigned long next;
1148 pfn -= addr >> PAGE_SHIFT;
1149 pmd = pmd_alloc(mm, pud, addr);
1150 if (!pmd)
1151 return -ENOMEM;
1152 do {
1153 next = pmd_addr_end(addr, end);
1154 if (remap_pte_range(mm, pmd, addr, next,
1155 pfn + (addr >> PAGE_SHIFT), prot))
1156 return -ENOMEM;
1157 } while (pmd++, addr = next, addr != end);
1158 return 0;
1161 static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1162 unsigned long addr, unsigned long end,
1163 unsigned long pfn, pgprot_t prot)
1165 pud_t *pud;
1166 unsigned long next;
1168 pfn -= addr >> PAGE_SHIFT;
1169 pud = pud_alloc(mm, pgd, addr);
1170 if (!pud)
1171 return -ENOMEM;
1172 do {
1173 next = pud_addr_end(addr, end);
1174 if (remap_pmd_range(mm, pud, addr, next,
1175 pfn + (addr >> PAGE_SHIFT), prot))
1176 return -ENOMEM;
1177 } while (pud++, addr = next, addr != end);
1178 return 0;
1181 /* Note: this is only safe if the mm semaphore is held when called. */
1182 int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1183 unsigned long pfn, unsigned long size, pgprot_t prot)
1185 pgd_t *pgd;
1186 unsigned long next;
1187 unsigned long end = addr + size;
1188 struct mm_struct *mm = vma->vm_mm;
1189 int err;
1191 /*
1192 * Physically remapped pages are special. Tell the
1193 * rest of the world about it:
1194 * VM_IO tells people not to look at these pages
1195 * (accesses can have side effects).
1196 * VM_RESERVED tells swapout not to try to touch
1197 * this region.
1198 */
1199 vma->vm_flags |= VM_IO | VM_RESERVED;
1201 BUG_ON(addr >= end);
1202 pfn -= addr >> PAGE_SHIFT;
1203 pgd = pgd_offset(mm, addr);
1204 flush_cache_range(vma, addr, end);
1205 spin_lock(&mm->page_table_lock);
1206 do {
1207 next = pgd_addr_end(addr, end);
1208 err = remap_pud_range(mm, pgd, addr, next,
1209 pfn + (addr >> PAGE_SHIFT), prot);
1210 if (err)
1211 break;
1212 } while (pgd++, addr = next, addr != end);
1213 spin_unlock(&mm->page_table_lock);
1214 return err;
1216 EXPORT_SYMBOL(remap_pfn_range);
1218 static inline int generic_pte_range(struct mm_struct *mm,
1219 pmd_t *pmd,
1220 unsigned long addr,
1221 unsigned long end,
1222 pte_fn_t fn, void *data)
1224 pte_t *pte;
1225 int err;
1226 struct page *pte_page;
1228 pte = (mm == &init_mm) ?
1229 pte_alloc_kernel(mm, pmd, addr) :
1230 pte_alloc_map(mm, pmd, addr);
1231 if (!pte)
1232 return -ENOMEM;
1234 pte_page = pmd_page(*pmd);
1236 do {
1237 err = fn(pte, pte_page, addr, data);
1238 if (err)
1239 break;
1240 } while (pte++, addr += PAGE_SIZE, addr != end);
1242 if (mm != &init_mm)
1243 pte_unmap(pte-1);
1244 return err;
1248 static inline int generic_pmd_range(struct mm_struct *mm,
1249 pud_t *pud,
1250 unsigned long addr,
1251 unsigned long end,
1252 pte_fn_t fn, void *data)
1254 pmd_t *pmd;
1255 unsigned long next;
1256 int err;
1258 pmd = pmd_alloc(mm, pud, addr);
1259 if (!pmd)
1260 return -ENOMEM;
1261 do {
1262 next = pmd_addr_end(addr, end);
1263 err = generic_pte_range(mm, pmd, addr, next, fn, data);
1264 if (err)
1265 break;
1266 } while (pmd++, addr = next, addr != end);
1267 return err;
1270 static inline int generic_pud_range(struct mm_struct *mm, pgd_t *pgd,
1271 unsigned long addr,
1272 unsigned long end,
1273 pte_fn_t fn, void *data)
1275 pud_t *pud;
1276 unsigned long next;
1277 int err;
1279 pud = pud_alloc(mm, pgd, addr);
1280 if (!pud)
1281 return -ENOMEM;
1282 do {
1283 next = pud_addr_end(addr, end);
1284 err = generic_pmd_range(mm, pud, addr, next, fn, data);
1285 if (err)
1286 break;
1287 } while (pud++, addr = next, addr != end);
1288 return err;
1291 /*
1292 * Scan a region of virtual memory, filling in page tables as necessary
1293 * and calling a provided function on each leaf page table.
1294 */
1295 int generic_page_range(struct mm_struct *mm, unsigned long addr,
1296 unsigned long size, pte_fn_t fn, void *data)
1298 pgd_t *pgd;
1299 unsigned long next;
1300 unsigned long end = addr + size;
1301 int err;
1303 BUG_ON(addr >= end);
1304 pgd = pgd_offset(mm, addr);
1305 spin_lock(&mm->page_table_lock);
1306 do {
1307 next = pgd_addr_end(addr, end);
1308 err = generic_pud_range(mm, pgd, addr, next, fn, data);
1309 if (err)
1310 break;
1311 } while (pgd++, addr = next, addr != end);
1312 spin_unlock(&mm->page_table_lock);
1313 return err;
1316 /*
1317 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1318 * servicing faults for write access. In the normal case, do always want
1319 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1320 * that do not have writing enabled, when used by access_process_vm.
1321 */
1322 static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1324 if (likely(vma->vm_flags & VM_WRITE))
1325 pte = pte_mkwrite(pte);
1326 return pte;
1329 /*
1330 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock
1331 */
1332 static inline void break_cow(struct vm_area_struct * vma, struct page * new_page, unsigned long address,
1333 pte_t *page_table)
1335 pte_t entry;
1337 entry = maybe_mkwrite(pte_mkdirty(mk_pte(new_page, vma->vm_page_prot)),
1338 vma);
1339 ptep_establish(vma, address, page_table, entry);
1340 update_mmu_cache(vma, address, entry);
1341 lazy_mmu_prot_update(entry);
1344 /*
1345 * This routine handles present pages, when users try to write
1346 * to a shared page. It is done by copying the page to a new address
1347 * and decrementing the shared-page counter for the old page.
1349 * Goto-purists beware: the only reason for goto's here is that it results
1350 * in better assembly code.. The "default" path will see no jumps at all.
1352 * Note that this routine assumes that the protection checks have been
1353 * done by the caller (the low-level page fault routine in most cases).
1354 * Thus we can safely just mark it writable once we've done any necessary
1355 * COW.
1357 * We also mark the page dirty at this point even though the page will
1358 * change only once the write actually happens. This avoids a few races,
1359 * and potentially makes it more efficient.
1361 * We hold the mm semaphore and the page_table_lock on entry and exit
1362 * with the page_table_lock released.
1363 */
1364 static int do_wp_page(struct mm_struct *mm, struct vm_area_struct * vma,
1365 unsigned long address, pte_t *page_table, pmd_t *pmd, pte_t pte)
1367 struct page *old_page, *new_page;
1368 unsigned long pfn = pte_pfn(pte);
1369 pte_t entry;
1370 struct page invalid_page;
1372 if (unlikely(!pfn_valid(pfn))) {
1373 /* This can happen with /dev/mem (PROT_WRITE, MAP_PRIVATE). */
1374 invalid_page.flags = (1<<PG_reserved) | (1<<PG_locked);
1375 old_page = &invalid_page;
1376 } else {
1377 old_page = pfn_to_page(pfn);
1380 if (!TestSetPageLocked(old_page)) {
1381 int reuse = can_share_swap_page(old_page);
1382 unlock_page(old_page);
1383 if (reuse) {
1384 flush_cache_page(vma, address, pfn);
1385 entry = maybe_mkwrite(pte_mkyoung(pte_mkdirty(pte)),
1386 vma);
1387 ptep_set_access_flags(vma, address, page_table, entry, 1);
1388 update_mmu_cache(vma, address, entry);
1389 lazy_mmu_prot_update(entry);
1390 pte_unmap(page_table);
1391 spin_unlock(&mm->page_table_lock);
1392 return VM_FAULT_MINOR;
1395 pte_unmap(page_table);
1397 /*
1398 * Ok, we need to copy. Oh, well..
1399 */
1400 if (!PageReserved(old_page))
1401 page_cache_get(old_page);
1402 spin_unlock(&mm->page_table_lock);
1404 if (unlikely(anon_vma_prepare(vma)))
1405 goto no_new_page;
1406 if (old_page == ZERO_PAGE(address)) {
1407 new_page = alloc_zeroed_user_highpage(vma, address);
1408 if (!new_page)
1409 goto no_new_page;
1410 } else {
1411 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1412 if (!new_page)
1413 goto no_new_page;
1414 if (old_page == &invalid_page) {
1415 char *vto = kmap_atomic(new_page, KM_USER1);
1416 copy_page(vto, (void *)(address & PAGE_MASK));
1417 kunmap_atomic(vto, KM_USER1);
1418 } else {
1419 copy_user_highpage(new_page, old_page, address);
1422 /*
1423 * Re-check the pte - we dropped the lock
1424 */
1425 spin_lock(&mm->page_table_lock);
1426 page_table = pte_offset_map(pmd, address);
1427 if (likely(pte_same(*page_table, pte))) {
1428 if (PageAnon(old_page))
1429 dec_mm_counter(mm, anon_rss);
1430 if (PageReserved(old_page))
1431 inc_mm_counter(mm, rss);
1432 else
1433 page_remove_rmap(old_page);
1434 flush_cache_page(vma, address, pfn);
1435 break_cow(vma, new_page, address, page_table);
1436 lru_cache_add_active(new_page);
1437 page_add_anon_rmap(new_page, vma, address);
1439 /* Free the old page.. */
1440 new_page = old_page;
1442 pte_unmap(page_table);
1443 page_cache_release(new_page);
1444 page_cache_release(old_page);
1445 spin_unlock(&mm->page_table_lock);
1446 return VM_FAULT_MINOR;
1448 no_new_page:
1449 page_cache_release(old_page);
1450 return VM_FAULT_OOM;
1453 /*
1454 * Helper functions for unmap_mapping_range().
1456 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1458 * We have to restart searching the prio_tree whenever we drop the lock,
1459 * since the iterator is only valid while the lock is held, and anyway
1460 * a later vma might be split and reinserted earlier while lock dropped.
1462 * The list of nonlinear vmas could be handled more efficiently, using
1463 * a placeholder, but handle it in the same way until a need is shown.
1464 * It is important to search the prio_tree before nonlinear list: a vma
1465 * may become nonlinear and be shifted from prio_tree to nonlinear list
1466 * while the lock is dropped; but never shifted from list to prio_tree.
1468 * In order to make forward progress despite restarting the search,
1469 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1470 * quickly skip it next time around. Since the prio_tree search only
1471 * shows us those vmas affected by unmapping the range in question, we
1472 * can't efficiently keep all vmas in step with mapping->truncate_count:
1473 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1474 * mapping->truncate_count and vma->vm_truncate_count are protected by
1475 * i_mmap_lock.
1477 * In order to make forward progress despite repeatedly restarting some
1478 * large vma, note the restart_addr from unmap_vmas when it breaks out:
1479 * and restart from that address when we reach that vma again. It might
1480 * have been split or merged, shrunk or extended, but never shifted: so
1481 * restart_addr remains valid so long as it remains in the vma's range.
1482 * unmap_mapping_range forces truncate_count to leap over page-aligned
1483 * values so we can save vma's restart_addr in its truncate_count field.
1484 */
1485 #define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1487 static void reset_vma_truncate_counts(struct address_space *mapping)
1489 struct vm_area_struct *vma;
1490 struct prio_tree_iter iter;
1492 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1493 vma->vm_truncate_count = 0;
1494 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1495 vma->vm_truncate_count = 0;
1498 static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1499 unsigned long start_addr, unsigned long end_addr,
1500 struct zap_details *details)
1502 unsigned long restart_addr;
1503 int need_break;
1505 again:
1506 restart_addr = vma->vm_truncate_count;
1507 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1508 start_addr = restart_addr;
1509 if (start_addr >= end_addr) {
1510 /* Top of vma has been split off since last time */
1511 vma->vm_truncate_count = details->truncate_count;
1512 return 0;
1516 restart_addr = zap_page_range(vma, start_addr,
1517 end_addr - start_addr, details);
1519 /*
1520 * We cannot rely on the break test in unmap_vmas:
1521 * on the one hand, we don't want to restart our loop
1522 * just because that broke out for the page_table_lock;
1523 * on the other hand, it does no test when vma is small.
1524 */
1525 need_break = need_resched() ||
1526 need_lockbreak(details->i_mmap_lock);
1528 if (restart_addr >= end_addr) {
1529 /* We have now completed this vma: mark it so */
1530 vma->vm_truncate_count = details->truncate_count;
1531 if (!need_break)
1532 return 0;
1533 } else {
1534 /* Note restart_addr in vma's truncate_count field */
1535 vma->vm_truncate_count = restart_addr;
1536 if (!need_break)
1537 goto again;
1540 spin_unlock(details->i_mmap_lock);
1541 cond_resched();
1542 spin_lock(details->i_mmap_lock);
1543 return -EINTR;
1546 static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1547 struct zap_details *details)
1549 struct vm_area_struct *vma;
1550 struct prio_tree_iter iter;
1551 pgoff_t vba, vea, zba, zea;
1553 restart:
1554 vma_prio_tree_foreach(vma, &iter, root,
1555 details->first_index, details->last_index) {
1556 /* Skip quickly over those we have already dealt with */
1557 if (vma->vm_truncate_count == details->truncate_count)
1558 continue;
1560 vba = vma->vm_pgoff;
1561 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1562 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1563 zba = details->first_index;
1564 if (zba < vba)
1565 zba = vba;
1566 zea = details->last_index;
1567 if (zea > vea)
1568 zea = vea;
1570 if (unmap_mapping_range_vma(vma,
1571 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1572 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1573 details) < 0)
1574 goto restart;
1578 static inline void unmap_mapping_range_list(struct list_head *head,
1579 struct zap_details *details)
1581 struct vm_area_struct *vma;
1583 /*
1584 * In nonlinear VMAs there is no correspondence between virtual address
1585 * offset and file offset. So we must perform an exhaustive search
1586 * across *all* the pages in each nonlinear VMA, not just the pages
1587 * whose virtual address lies outside the file truncation point.
1588 */
1589 restart:
1590 list_for_each_entry(vma, head, shared.vm_set.list) {
1591 /* Skip quickly over those we have already dealt with */
1592 if (vma->vm_truncate_count == details->truncate_count)
1593 continue;
1594 details->nonlinear_vma = vma;
1595 if (unmap_mapping_range_vma(vma, vma->vm_start,
1596 vma->vm_end, details) < 0)
1597 goto restart;
1601 /**
1602 * unmap_mapping_range - unmap the portion of all mmaps
1603 * in the specified address_space corresponding to the specified
1604 * page range in the underlying file.
1605 * @address_space: the address space containing mmaps to be unmapped.
1606 * @holebegin: byte in first page to unmap, relative to the start of
1607 * the underlying file. This will be rounded down to a PAGE_SIZE
1608 * boundary. Note that this is different from vmtruncate(), which
1609 * must keep the partial page. In contrast, we must get rid of
1610 * partial pages.
1611 * @holelen: size of prospective hole in bytes. This will be rounded
1612 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1613 * end of the file.
1614 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1615 * but 0 when invalidating pagecache, don't throw away private data.
1616 */
1617 void unmap_mapping_range(struct address_space *mapping,
1618 loff_t const holebegin, loff_t const holelen, int even_cows)
1620 struct zap_details details;
1621 pgoff_t hba = holebegin >> PAGE_SHIFT;
1622 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1624 /* Check for overflow. */
1625 if (sizeof(holelen) > sizeof(hlen)) {
1626 long long holeend =
1627 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1628 if (holeend & ~(long long)ULONG_MAX)
1629 hlen = ULONG_MAX - hba + 1;
1632 details.check_mapping = even_cows? NULL: mapping;
1633 details.nonlinear_vma = NULL;
1634 details.first_index = hba;
1635 details.last_index = hba + hlen - 1;
1636 if (details.last_index < details.first_index)
1637 details.last_index = ULONG_MAX;
1638 details.i_mmap_lock = &mapping->i_mmap_lock;
1640 spin_lock(&mapping->i_mmap_lock);
1642 /* serialize i_size write against truncate_count write */
1643 smp_wmb();
1644 /* Protect against page faults, and endless unmapping loops */
1645 mapping->truncate_count++;
1646 /*
1647 * For archs where spin_lock has inclusive semantics like ia64
1648 * this smp_mb() will prevent to read pagetable contents
1649 * before the truncate_count increment is visible to
1650 * other cpus.
1651 */
1652 smp_mb();
1653 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1654 if (mapping->truncate_count == 0)
1655 reset_vma_truncate_counts(mapping);
1656 mapping->truncate_count++;
1658 details.truncate_count = mapping->truncate_count;
1660 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1661 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1662 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1663 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1664 spin_unlock(&mapping->i_mmap_lock);
1666 EXPORT_SYMBOL(unmap_mapping_range);
1668 /*
1669 * Handle all mappings that got truncated by a "truncate()"
1670 * system call.
1672 * NOTE! We have to be ready to update the memory sharing
1673 * between the file and the memory map for a potential last
1674 * incomplete page. Ugly, but necessary.
1675 */
1676 int vmtruncate(struct inode * inode, loff_t offset)
1678 struct address_space *mapping = inode->i_mapping;
1679 unsigned long limit;
1681 if (inode->i_size < offset)
1682 goto do_expand;
1683 /*
1684 * truncation of in-use swapfiles is disallowed - it would cause
1685 * subsequent swapout to scribble on the now-freed blocks.
1686 */
1687 if (IS_SWAPFILE(inode))
1688 goto out_busy;
1689 i_size_write(inode, offset);
1690 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1691 truncate_inode_pages(mapping, offset);
1692 goto out_truncate;
1694 do_expand:
1695 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1696 if (limit != RLIM_INFINITY && offset > limit)
1697 goto out_sig;
1698 if (offset > inode->i_sb->s_maxbytes)
1699 goto out_big;
1700 i_size_write(inode, offset);
1702 out_truncate:
1703 if (inode->i_op && inode->i_op->truncate)
1704 inode->i_op->truncate(inode);
1705 return 0;
1706 out_sig:
1707 send_sig(SIGXFSZ, current, 0);
1708 out_big:
1709 return -EFBIG;
1710 out_busy:
1711 return -ETXTBSY;
1714 EXPORT_SYMBOL(vmtruncate);
1716 /*
1717 * Primitive swap readahead code. We simply read an aligned block of
1718 * (1 << page_cluster) entries in the swap area. This method is chosen
1719 * because it doesn't cost us any seek time. We also make sure to queue
1720 * the 'original' request together with the readahead ones...
1722 * This has been extended to use the NUMA policies from the mm triggering
1723 * the readahead.
1725 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1726 */
1727 void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1729 #ifdef CONFIG_NUMA
1730 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1731 #endif
1732 int i, num;
1733 struct page *new_page;
1734 unsigned long offset;
1736 /*
1737 * Get the number of handles we should do readahead io to.
1738 */
1739 num = valid_swaphandles(entry, &offset);
1740 for (i = 0; i < num; offset++, i++) {
1741 /* Ok, do the async read-ahead now */
1742 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1743 offset), vma, addr);
1744 if (!new_page)
1745 break;
1746 page_cache_release(new_page);
1747 #ifdef CONFIG_NUMA
1748 /*
1749 * Find the next applicable VMA for the NUMA policy.
1750 */
1751 addr += PAGE_SIZE;
1752 if (addr == 0)
1753 vma = NULL;
1754 if (vma) {
1755 if (addr >= vma->vm_end) {
1756 vma = next_vma;
1757 next_vma = vma ? vma->vm_next : NULL;
1759 if (vma && addr < vma->vm_start)
1760 vma = NULL;
1761 } else {
1762 if (next_vma && addr >= next_vma->vm_start) {
1763 vma = next_vma;
1764 next_vma = vma->vm_next;
1767 #endif
1769 lru_add_drain(); /* Push any new pages onto the LRU now */
1772 /*
1773 * We hold the mm semaphore and the page_table_lock on entry and
1774 * should release the pagetable lock on exit..
1775 */
1776 static int do_swap_page(struct mm_struct * mm,
1777 struct vm_area_struct * vma, unsigned long address,
1778 pte_t *page_table, pmd_t *pmd, pte_t orig_pte, int write_access)
1780 struct page *page;
1781 swp_entry_t entry = pte_to_swp_entry(orig_pte);
1782 pte_t pte;
1783 int ret = VM_FAULT_MINOR;
1785 pte_unmap(page_table);
1786 spin_unlock(&mm->page_table_lock);
1787 page = lookup_swap_cache(entry);
1788 if (!page) {
1789 swapin_readahead(entry, address, vma);
1790 page = read_swap_cache_async(entry, vma, address);
1791 if (!page) {
1792 /*
1793 * Back out if somebody else faulted in this pte while
1794 * we released the page table lock.
1795 */
1796 spin_lock(&mm->page_table_lock);
1797 page_table = pte_offset_map(pmd, address);
1798 if (likely(pte_same(*page_table, orig_pte)))
1799 ret = VM_FAULT_OOM;
1800 else
1801 ret = VM_FAULT_MINOR;
1802 pte_unmap(page_table);
1803 spin_unlock(&mm->page_table_lock);
1804 goto out;
1807 /* Had to read the page from swap area: Major fault */
1808 ret = VM_FAULT_MAJOR;
1809 inc_page_state(pgmajfault);
1810 grab_swap_token();
1813 mark_page_accessed(page);
1814 lock_page(page);
1816 /*
1817 * Back out if somebody else faulted in this pte while we
1818 * released the page table lock.
1819 */
1820 spin_lock(&mm->page_table_lock);
1821 page_table = pte_offset_map(pmd, address);
1822 if (unlikely(!pte_same(*page_table, orig_pte))) {
1823 ret = VM_FAULT_MINOR;
1824 goto out_nomap;
1827 if (unlikely(!PageUptodate(page))) {
1828 ret = VM_FAULT_SIGBUS;
1829 goto out_nomap;
1832 /* The page isn't present yet, go ahead with the fault. */
1834 swap_free(entry);
1835 if (vm_swap_full())
1836 remove_exclusive_swap_page(page);
1838 inc_mm_counter(mm, rss);
1839 pte = mk_pte(page, vma->vm_page_prot);
1840 if (write_access && can_share_swap_page(page)) {
1841 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1842 write_access = 0;
1844 unlock_page(page);
1846 flush_icache_page(vma, page);
1847 set_pte_at(mm, address, page_table, pte);
1848 page_add_anon_rmap(page, vma, address);
1850 if (write_access) {
1851 if (do_wp_page(mm, vma, address,
1852 page_table, pmd, pte) == VM_FAULT_OOM)
1853 ret = VM_FAULT_OOM;
1854 goto out;
1857 /* No need to invalidate - it was non-present before */
1858 update_mmu_cache(vma, address, pte);
1859 lazy_mmu_prot_update(pte);
1860 pte_unmap(page_table);
1861 spin_unlock(&mm->page_table_lock);
1862 out:
1863 return ret;
1864 out_nomap:
1865 pte_unmap(page_table);
1866 spin_unlock(&mm->page_table_lock);
1867 unlock_page(page);
1868 page_cache_release(page);
1869 goto out;
1872 /*
1873 * We are called with the MM semaphore and page_table_lock
1874 * spinlock held to protect against concurrent faults in
1875 * multithreaded programs.
1876 */
1877 static int
1878 do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1879 pte_t *page_table, pmd_t *pmd, int write_access,
1880 unsigned long addr)
1882 pte_t entry;
1883 struct page * page = ZERO_PAGE(addr);
1885 /* Read-only mapping of ZERO_PAGE. */
1886 entry = pte_wrprotect(mk_pte(ZERO_PAGE(addr), vma->vm_page_prot));
1888 /* ..except if it's a write access */
1889 if (write_access) {
1890 /* Allocate our own private page. */
1891 pte_unmap(page_table);
1892 spin_unlock(&mm->page_table_lock);
1894 if (unlikely(anon_vma_prepare(vma)))
1895 goto no_mem;
1896 page = alloc_zeroed_user_highpage(vma, addr);
1897 if (!page)
1898 goto no_mem;
1900 spin_lock(&mm->page_table_lock);
1901 page_table = pte_offset_map(pmd, addr);
1903 if (!pte_none(*page_table)) {
1904 pte_unmap(page_table);
1905 page_cache_release(page);
1906 spin_unlock(&mm->page_table_lock);
1907 goto out;
1909 inc_mm_counter(mm, rss);
1910 entry = maybe_mkwrite(pte_mkdirty(mk_pte(page,
1911 vma->vm_page_prot)),
1912 vma);
1913 lru_cache_add_active(page);
1914 SetPageReferenced(page);
1915 page_add_anon_rmap(page, vma, addr);
1918 set_pte_at(mm, addr, page_table, entry);
1919 pte_unmap(page_table);
1921 /* No need to invalidate - it was non-present before */
1922 update_mmu_cache(vma, addr, entry);
1923 lazy_mmu_prot_update(entry);
1924 spin_unlock(&mm->page_table_lock);
1925 out:
1926 return VM_FAULT_MINOR;
1927 no_mem:
1928 return VM_FAULT_OOM;
1931 /*
1932 * do_no_page() tries to create a new page mapping. It aggressively
1933 * tries to share with existing pages, but makes a separate copy if
1934 * the "write_access" parameter is true in order to avoid the next
1935 * page fault.
1937 * As this is called only for pages that do not currently exist, we
1938 * do not need to flush old virtual caches or the TLB.
1940 * This is called with the MM semaphore held and the page table
1941 * spinlock held. Exit with the spinlock released.
1942 */
1943 static int
1944 do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1945 unsigned long address, int write_access, pte_t *page_table, pmd_t *pmd)
1947 struct page * new_page;
1948 struct address_space *mapping = NULL;
1949 pte_t entry;
1950 unsigned int sequence = 0;
1951 int ret = VM_FAULT_MINOR;
1952 int anon = 0;
1954 if (!vma->vm_ops || !vma->vm_ops->nopage)
1955 return do_anonymous_page(mm, vma, page_table,
1956 pmd, write_access, address);
1957 pte_unmap(page_table);
1958 spin_unlock(&mm->page_table_lock);
1960 if (vma->vm_file) {
1961 mapping = vma->vm_file->f_mapping;
1962 sequence = mapping->truncate_count;
1963 smp_rmb(); /* serializes i_size against truncate_count */
1965 retry:
1966 cond_resched();
1967 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1968 /*
1969 * No smp_rmb is needed here as long as there's a full
1970 * spin_lock/unlock sequence inside the ->nopage callback
1971 * (for the pagecache lookup) that acts as an implicit
1972 * smp_mb() and prevents the i_size read to happen
1973 * after the next truncate_count read.
1974 */
1976 /* no page was available -- either SIGBUS or OOM */
1977 if (new_page == NOPAGE_SIGBUS)
1978 return VM_FAULT_SIGBUS;
1979 if (new_page == NOPAGE_OOM)
1980 return VM_FAULT_OOM;
1982 /*
1983 * Should we do an early C-O-W break?
1984 */
1985 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1986 struct page *page;
1988 if (unlikely(anon_vma_prepare(vma)))
1989 goto oom;
1990 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1991 if (!page)
1992 goto oom;
1993 copy_user_highpage(page, new_page, address);
1994 page_cache_release(new_page);
1995 new_page = page;
1996 anon = 1;
1999 spin_lock(&mm->page_table_lock);
2000 /*
2001 * For a file-backed vma, someone could have truncated or otherwise
2002 * invalidated this page. If unmap_mapping_range got called,
2003 * retry getting the page.
2004 */
2005 if (mapping && unlikely(sequence != mapping->truncate_count)) {
2006 sequence = mapping->truncate_count;
2007 spin_unlock(&mm->page_table_lock);
2008 page_cache_release(new_page);
2009 goto retry;
2011 page_table = pte_offset_map(pmd, address);
2013 /*
2014 * This silly early PAGE_DIRTY setting removes a race
2015 * due to the bad i386 page protection. But it's valid
2016 * for other architectures too.
2018 * Note that if write_access is true, we either now have
2019 * an exclusive copy of the page, or this is a shared mapping,
2020 * so we can make it writable and dirty to avoid having to
2021 * handle that later.
2022 */
2023 /* Only go through if we didn't race with anybody else... */
2024 if (pte_none(*page_table)) {
2025 if (!PageReserved(new_page))
2026 inc_mm_counter(mm, rss);
2028 flush_icache_page(vma, new_page);
2029 entry = mk_pte(new_page, vma->vm_page_prot);
2030 if (write_access)
2031 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2032 set_pte_at(mm, address, page_table, entry);
2033 if (anon) {
2034 lru_cache_add_active(new_page);
2035 page_add_anon_rmap(new_page, vma, address);
2036 } else
2037 page_add_file_rmap(new_page);
2038 pte_unmap(page_table);
2039 } else {
2040 /* One of our sibling threads was faster, back out. */
2041 pte_unmap(page_table);
2042 page_cache_release(new_page);
2043 spin_unlock(&mm->page_table_lock);
2044 goto out;
2047 /* no need to invalidate: a not-present page shouldn't be cached */
2048 update_mmu_cache(vma, address, entry);
2049 lazy_mmu_prot_update(entry);
2050 spin_unlock(&mm->page_table_lock);
2051 out:
2052 return ret;
2053 oom:
2054 page_cache_release(new_page);
2055 ret = VM_FAULT_OOM;
2056 goto out;
2059 /*
2060 * Fault of a previously existing named mapping. Repopulate the pte
2061 * from the encoded file_pte if possible. This enables swappable
2062 * nonlinear vmas.
2063 */
2064 static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma,
2065 unsigned long address, int write_access, pte_t *pte, pmd_t *pmd)
2067 unsigned long pgoff;
2068 int err;
2070 BUG_ON(!vma->vm_ops || !vma->vm_ops->nopage);
2071 /*
2072 * Fall back to the linear mapping if the fs does not support
2073 * ->populate:
2074 */
2075 if (!vma->vm_ops || !vma->vm_ops->populate ||
2076 (write_access && !(vma->vm_flags & VM_SHARED))) {
2077 pte_clear(mm, address, pte);
2078 return do_no_page(mm, vma, address, write_access, pte, pmd);
2081 pgoff = pte_to_pgoff(*pte);
2083 pte_unmap(pte);
2084 spin_unlock(&mm->page_table_lock);
2086 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE, vma->vm_page_prot, pgoff, 0);
2087 if (err == -ENOMEM)
2088 return VM_FAULT_OOM;
2089 if (err)
2090 return VM_FAULT_SIGBUS;
2091 return VM_FAULT_MAJOR;
2094 /*
2095 * These routines also need to handle stuff like marking pages dirty
2096 * and/or accessed for architectures that don't do it in hardware (most
2097 * RISC architectures). The early dirtying is also good on the i386.
2099 * There is also a hook called "update_mmu_cache()" that architectures
2100 * with external mmu caches can use to update those (ie the Sparc or
2101 * PowerPC hashed page tables that act as extended TLBs).
2103 * Note the "page_table_lock". It is to protect against kswapd removing
2104 * pages from under us. Note that kswapd only ever _removes_ pages, never
2105 * adds them. As such, once we have noticed that the page is not present,
2106 * we can drop the lock early.
2108 * The adding of pages is protected by the MM semaphore (which we hold),
2109 * so we don't need to worry about a page being suddenly been added into
2110 * our VM.
2112 * We enter with the pagetable spinlock held, we are supposed to
2113 * release it when done.
2114 */
2115 static inline int handle_pte_fault(struct mm_struct *mm,
2116 struct vm_area_struct * vma, unsigned long address,
2117 int write_access, pte_t *pte, pmd_t *pmd)
2119 pte_t entry;
2121 entry = *pte;
2122 if (!pte_present(entry)) {
2123 /*
2124 * If it truly wasn't present, we know that kswapd
2125 * and the PTE updates will not touch it later. So
2126 * drop the lock.
2127 */
2128 if (pte_none(entry))
2129 return do_no_page(mm, vma, address, write_access, pte, pmd);
2130 if (pte_file(entry))
2131 return do_file_page(mm, vma, address, write_access, pte, pmd);
2132 return do_swap_page(mm, vma, address, pte, pmd, entry, write_access);
2135 if (write_access) {
2136 if (!pte_write(entry))
2137 return do_wp_page(mm, vma, address, pte, pmd, entry);
2139 entry = pte_mkdirty(entry);
2141 entry = pte_mkyoung(entry);
2142 ptep_set_access_flags(vma, address, pte, entry, write_access);
2143 update_mmu_cache(vma, address, entry);
2144 lazy_mmu_prot_update(entry);
2145 pte_unmap(pte);
2146 spin_unlock(&mm->page_table_lock);
2147 return VM_FAULT_MINOR;
2150 /*
2151 * By the time we get here, we already hold the mm semaphore
2152 */
2153 int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct * vma,
2154 unsigned long address, int write_access)
2156 pgd_t *pgd;
2157 pud_t *pud;
2158 pmd_t *pmd;
2159 pte_t *pte;
2161 __set_current_state(TASK_RUNNING);
2163 inc_page_state(pgfault);
2165 if (is_vm_hugetlb_page(vma))
2166 return VM_FAULT_SIGBUS; /* mapping truncation does this. */
2168 /*
2169 * We need the page table lock to synchronize with kswapd
2170 * and the SMP-safe atomic PTE updates.
2171 */
2172 pgd = pgd_offset(mm, address);
2173 spin_lock(&mm->page_table_lock);
2175 pud = pud_alloc(mm, pgd, address);
2176 if (!pud)
2177 goto oom;
2179 pmd = pmd_alloc(mm, pud, address);
2180 if (!pmd)
2181 goto oom;
2183 pte = pte_alloc_map(mm, pmd, address);
2184 if (!pte)
2185 goto oom;
2187 return handle_pte_fault(mm, vma, address, write_access, pte, pmd);
2189 oom:
2190 spin_unlock(&mm->page_table_lock);
2191 return VM_FAULT_OOM;
2194 #ifndef __PAGETABLE_PUD_FOLDED
2195 /*
2196 * Allocate page upper directory.
2198 * We've already handled the fast-path in-line, and we own the
2199 * page table lock.
2200 */
2201 pud_t fastcall *__pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2203 pud_t *new;
2205 spin_unlock(&mm->page_table_lock);
2206 new = pud_alloc_one(mm, address);
2207 spin_lock(&mm->page_table_lock);
2208 if (!new)
2209 return NULL;
2211 /*
2212 * Because we dropped the lock, we should re-check the
2213 * entry, as somebody else could have populated it..
2214 */
2215 if (pgd_present(*pgd)) {
2216 pud_free(new);
2217 goto out;
2219 pgd_populate(mm, pgd, new);
2220 out:
2221 return pud_offset(pgd, address);
2223 #endif /* __PAGETABLE_PUD_FOLDED */
2225 #ifndef __PAGETABLE_PMD_FOLDED
2226 /*
2227 * Allocate page middle directory.
2229 * We've already handled the fast-path in-line, and we own the
2230 * page table lock.
2231 */
2232 pmd_t fastcall *__pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2234 pmd_t *new;
2236 spin_unlock(&mm->page_table_lock);
2237 new = pmd_alloc_one(mm, address);
2238 spin_lock(&mm->page_table_lock);
2239 if (!new)
2240 return NULL;
2242 /*
2243 * Because we dropped the lock, we should re-check the
2244 * entry, as somebody else could have populated it..
2245 */
2246 #ifndef __ARCH_HAS_4LEVEL_HACK
2247 if (pud_present(*pud)) {
2248 pmd_free(new);
2249 goto out;
2251 pud_populate(mm, pud, new);
2252 #else
2253 if (pgd_present(*pud)) {
2254 pmd_free(new);
2255 goto out;
2257 pgd_populate(mm, pud, new);
2258 #endif /* __ARCH_HAS_4LEVEL_HACK */
2260 out:
2261 return pmd_offset(pud, address);
2263 #endif /* __PAGETABLE_PMD_FOLDED */
2265 int make_pages_present(unsigned long addr, unsigned long end)
2267 int ret, len, write;
2268 struct vm_area_struct * vma;
2270 vma = find_vma(current->mm, addr);
2271 if (!vma)
2272 return -1;
2273 write = (vma->vm_flags & VM_WRITE) != 0;
2274 if (addr >= end)
2275 BUG();
2276 if (end > vma->vm_end)
2277 BUG();
2278 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2279 ret = get_user_pages(current, current->mm, addr,
2280 len, write, 0, NULL, NULL);
2281 if (ret < 0)
2282 return ret;
2283 return ret == len ? 0 : -1;
2286 /*
2287 * Map a vmalloc()-space virtual address to the physical page.
2288 */
2289 struct page * vmalloc_to_page(void * vmalloc_addr)
2291 unsigned long addr = (unsigned long) vmalloc_addr;
2292 struct page *page = NULL;
2293 pgd_t *pgd = pgd_offset_k(addr);
2294 pud_t *pud;
2295 pmd_t *pmd;
2296 pte_t *ptep, pte;
2298 if (!pgd_none(*pgd)) {
2299 pud = pud_offset(pgd, addr);
2300 if (!pud_none(*pud)) {
2301 pmd = pmd_offset(pud, addr);
2302 if (!pmd_none(*pmd)) {
2303 ptep = pte_offset_map(pmd, addr);
2304 pte = *ptep;
2305 if (pte_present(pte))
2306 page = pte_page(pte);
2307 pte_unmap(ptep);
2311 return page;
2314 EXPORT_SYMBOL(vmalloc_to_page);
2316 /*
2317 * Map a vmalloc()-space virtual address to the physical page frame number.
2318 */
2319 unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2321 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2324 EXPORT_SYMBOL(vmalloc_to_pfn);
2326 /*
2327 * update_mem_hiwater
2328 * - update per process rss and vm high water data
2329 */
2330 void update_mem_hiwater(struct task_struct *tsk)
2332 if (tsk->mm) {
2333 unsigned long rss = get_mm_counter(tsk->mm, rss);
2335 if (tsk->mm->hiwater_rss < rss)
2336 tsk->mm->hiwater_rss = rss;
2337 if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
2338 tsk->mm->hiwater_vm = tsk->mm->total_vm;
2342 #if !defined(__HAVE_ARCH_GATE_AREA)
2344 #if defined(AT_SYSINFO_EHDR)
2345 struct vm_area_struct gate_vma;
2347 static int __init gate_vma_init(void)
2349 gate_vma.vm_mm = NULL;
2350 gate_vma.vm_start = FIXADDR_USER_START;
2351 gate_vma.vm_end = FIXADDR_USER_END;
2352 gate_vma.vm_page_prot = PAGE_READONLY;
2353 gate_vma.vm_flags = 0;
2354 return 0;
2356 __initcall(gate_vma_init);
2357 #endif
2359 struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2361 #ifdef AT_SYSINFO_EHDR
2362 return &gate_vma;
2363 #else
2364 return NULL;
2365 #endif
2368 int in_gate_area_no_task(unsigned long addr)
2370 #ifdef AT_SYSINFO_EHDR
2371 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2372 return 1;
2373 #endif
2374 return 0;
2377 #endif /* __HAVE_ARCH_GATE_AREA */