blob: a40e4b1cee4ff13cdca07b10a6afffa6933fcf30 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/memory.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
6
7/*
8 * demand-loading started 01.12.91 - seems it is high on the list of
9 * things wanted, and it should be easy to implement. - Linus
10 */
11
12/*
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
15 *
16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 * would have taken more than the 6M I have free, but it worked well as
18 * far as I could see.
19 *
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
21 */
22
23/*
24 * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 * thought has to go into this. Oh, well..
26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 * Found it. Everything seems to work now.
28 * 20.12.91 - Ok, making the swap-device changeable like the root.
29 */
30
31/*
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
34 *
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
37 *
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
39 */
40
41#include <linux/kernel_stat.h>
42#include <linux/mm.h>
43#include <linux/hugetlb.h>
44#include <linux/mman.h>
45#include <linux/swap.h>
46#include <linux/highmem.h>
47#include <linux/pagemap.h>
48#include <linux/rmap.h>
49#include <linux/module.h>
50#include <linux/init.h>
51
52#include <asm/pgalloc.h>
53#include <asm/uaccess.h>
54#include <asm/tlb.h>
55#include <asm/tlbflush.h>
56#include <asm/pgtable.h>
57
58#include <linux/swapops.h>
59#include <linux/elf.h>
60
Andy Whitcroftd41dee32005-06-23 00:07:54 -070061#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070062/* use the per-pgdat data instead for discontigmem - mbligh */
63unsigned long max_mapnr;
64struct page *mem_map;
65
66EXPORT_SYMBOL(max_mapnr);
67EXPORT_SYMBOL(mem_map);
68#endif
69
70unsigned long num_physpages;
71/*
72 * A number of key systems in x86 including ioremap() rely on the assumption
73 * that high_memory defines the upper bound on direct map memory, then end
74 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
75 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
76 * and ZONE_HIGHMEM.
77 */
78void * high_memory;
79unsigned long vmalloc_earlyreserve;
80
81EXPORT_SYMBOL(num_physpages);
82EXPORT_SYMBOL(high_memory);
83EXPORT_SYMBOL(vmalloc_earlyreserve);
84
85/*
86 * If a p?d_bad entry is found while walking page tables, report
87 * the error, before resetting entry to p?d_none. Usually (but
88 * very seldom) called out from the p?d_none_or_clear_bad macros.
89 */
90
91void pgd_clear_bad(pgd_t *pgd)
92{
93 pgd_ERROR(*pgd);
94 pgd_clear(pgd);
95}
96
97void pud_clear_bad(pud_t *pud)
98{
99 pud_ERROR(*pud);
100 pud_clear(pud);
101}
102
103void pmd_clear_bad(pmd_t *pmd)
104{
105 pmd_ERROR(*pmd);
106 pmd_clear(pmd);
107}
108
109/*
110 * Note: this doesn't free the actual pages themselves. That
111 * has been handled earlier when unmapping all the memory regions.
112 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700113static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
Hugh Dickinse0da3822005-04-19 13:29:15 -0700115 struct page *page = pmd_page(*pmd);
116 pmd_clear(pmd);
117 pte_free_tlb(tlb, page);
118 dec_page_state(nr_page_table_pages);
119 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120}
121
Hugh Dickinse0da3822005-04-19 13:29:15 -0700122static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
123 unsigned long addr, unsigned long end,
124 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
126 pmd_t *pmd;
127 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700128 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
Hugh Dickinse0da3822005-04-19 13:29:15 -0700130 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 do {
133 next = pmd_addr_end(addr, end);
134 if (pmd_none_or_clear_bad(pmd))
135 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700136 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137 } while (pmd++, addr = next, addr != end);
138
Hugh Dickinse0da3822005-04-19 13:29:15 -0700139 start &= PUD_MASK;
140 if (start < floor)
141 return;
142 if (ceiling) {
143 ceiling &= PUD_MASK;
144 if (!ceiling)
145 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700147 if (end - 1 > ceiling - 1)
148 return;
149
150 pmd = pmd_offset(pud, start);
151 pud_clear(pud);
152 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153}
154
Hugh Dickinse0da3822005-04-19 13:29:15 -0700155static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
156 unsigned long addr, unsigned long end,
157 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158{
159 pud_t *pud;
160 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700161 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700162
Hugh Dickinse0da3822005-04-19 13:29:15 -0700163 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 do {
166 next = pud_addr_end(addr, end);
167 if (pud_none_or_clear_bad(pud))
168 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700169 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 } while (pud++, addr = next, addr != end);
171
Hugh Dickinse0da3822005-04-19 13:29:15 -0700172 start &= PGDIR_MASK;
173 if (start < floor)
174 return;
175 if (ceiling) {
176 ceiling &= PGDIR_MASK;
177 if (!ceiling)
178 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700179 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700180 if (end - 1 > ceiling - 1)
181 return;
182
183 pud = pud_offset(pgd, start);
184 pgd_clear(pgd);
185 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186}
187
188/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700189 * This function frees user-level page tables of a process.
190 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 * Must be called with pagetable lock held.
192 */
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700193void free_pgd_range(struct mmu_gather **tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700194 unsigned long addr, unsigned long end,
195 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700196{
197 pgd_t *pgd;
198 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700199 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200
Hugh Dickinse0da3822005-04-19 13:29:15 -0700201 /*
202 * The next few lines have given us lots of grief...
203 *
204 * Why are we testing PMD* at this top level? Because often
205 * there will be no work to do at all, and we'd prefer not to
206 * go all the way down to the bottom just to discover that.
207 *
208 * Why all these "- 1"s? Because 0 represents both the bottom
209 * of the address space and the top of it (using -1 for the
210 * top wouldn't help much: the masks would do the wrong thing).
211 * The rule is that addr 0 and floor 0 refer to the bottom of
212 * the address space, but end 0 and ceiling 0 refer to the top
213 * Comparisons need to use "end - 1" and "ceiling - 1" (though
214 * that end 0 case should be mythical).
215 *
216 * Wherever addr is brought up or ceiling brought down, we must
217 * be careful to reject "the opposite 0" before it confuses the
218 * subsequent tests. But what about where end is brought down
219 * by PMD_SIZE below? no, end can't go down to 0 there.
220 *
221 * Whereas we round start (addr) and ceiling down, by different
222 * masks at different levels, in order to test whether a table
223 * now has no other vmas using it, so can be freed, we don't
224 * bother to round floor or end up - the tests don't need that.
225 */
226
227 addr &= PMD_MASK;
228 if (addr < floor) {
229 addr += PMD_SIZE;
230 if (!addr)
231 return;
232 }
233 if (ceiling) {
234 ceiling &= PMD_MASK;
235 if (!ceiling)
236 return;
237 }
238 if (end - 1 > ceiling - 1)
239 end -= PMD_SIZE;
240 if (addr > end - 1)
241 return;
242
243 start = addr;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700244 pgd = pgd_offset((*tlb)->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 do {
246 next = pgd_addr_end(addr, end);
247 if (pgd_none_or_clear_bad(pgd))
248 continue;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700249 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700251
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700252 if (!(*tlb)->fullmm)
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700253 flush_tlb_pgtables((*tlb)->mm, start, end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700254}
255
256void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700257 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700258{
259 while (vma) {
260 struct vm_area_struct *next = vma->vm_next;
261 unsigned long addr = vma->vm_start;
262
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700263 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
264 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700265 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700266 } else {
267 /*
268 * Optimization: gather nearby vmas into one call down
269 */
270 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
271 && !is_hugepage_only_range(vma->vm_mm, next->vm_start,
272 HPAGE_SIZE)) {
273 vma = next;
274 next = vma->vm_next;
275 }
276 free_pgd_range(tlb, addr, vma->vm_end,
277 floor, next? next->vm_start: ceiling);
278 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700279 vma = next;
280 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281}
282
Hugh Dickins1bb36302005-10-29 18:16:22 -0700283int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284{
Hugh Dickinsc74df322005-10-29 18:16:23 -0700285 struct page *new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700286 if (!new)
287 return -ENOMEM;
288
Hugh Dickinsc74df322005-10-29 18:16:23 -0700289 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700290 if (pmd_present(*pmd)) /* Another has populated it */
291 pte_free(new);
292 else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293 mm->nr_ptes++;
294 inc_page_state(nr_page_table_pages);
295 pmd_populate(mm, pmd, new);
296 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700297 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700298 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299}
300
Hugh Dickins1bb36302005-10-29 18:16:22 -0700301int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700303 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
304 if (!new)
305 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306
Hugh Dickins1bb36302005-10-29 18:16:22 -0700307 spin_lock(&init_mm.page_table_lock);
308 if (pmd_present(*pmd)) /* Another has populated it */
309 pte_free_kernel(new);
310 else
311 pmd_populate_kernel(&init_mm, pmd, new);
312 spin_unlock(&init_mm.page_table_lock);
313 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314}
315
Hugh Dickinsae859762005-10-29 18:16:05 -0700316static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
317{
318 if (file_rss)
319 add_mm_counter(mm, file_rss, file_rss);
320 if (anon_rss)
321 add_mm_counter(mm, anon_rss, anon_rss);
322}
323
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324/*
Nick Pigginb5810032005-10-29 18:16:12 -0700325 * This function is called to print an error when a pte in a
326 * !VM_RESERVED region is found pointing to an invalid pfn (which
327 * is an error.
328 *
329 * The calling function must still handle the error.
330 */
331void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
332{
333 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
334 "vm_flags = %lx, vaddr = %lx\n",
335 (long long)pte_val(pte),
336 (vma->vm_mm == current->mm ? current->comm : "???"),
337 vma->vm_flags, vaddr);
338 dump_stack();
339}
340
341/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342 * copy one vm_area from one task to the other. Assumes the page tables
343 * already present in the new task to be cleared in the whole range
344 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345 */
346
Hugh Dickins8c103762005-10-29 18:16:13 -0700347static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700349 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700350 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351{
Nick Pigginb5810032005-10-29 18:16:12 -0700352 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 pte_t pte = *src_pte;
354 struct page *page;
355 unsigned long pfn;
356
357 /* pte contains position in swap or file, so copy. */
358 if (unlikely(!pte_present(pte))) {
359 if (!pte_file(pte)) {
360 swap_duplicate(pte_to_swp_entry(pte));
361 /* make sure dst_mm is on swapoff's mmlist. */
362 if (unlikely(list_empty(&dst_mm->mmlist))) {
363 spin_lock(&mmlist_lock);
364 list_add(&dst_mm->mmlist, &src_mm->mmlist);
365 spin_unlock(&mmlist_lock);
366 }
367 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700368 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 }
370
Nick Pigginb5810032005-10-29 18:16:12 -0700371 /* If the region is VM_RESERVED, the mapping is not
372 * mapped via rmap - duplicate the pte as is.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 */
Nick Pigginb5810032005-10-29 18:16:12 -0700374 if (vm_flags & VM_RESERVED)
Hugh Dickinsae859762005-10-29 18:16:05 -0700375 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376
Nick Pigginb5810032005-10-29 18:16:12 -0700377 pfn = pte_pfn(pte);
378 /* If the pte points outside of valid memory but
379 * the region is not VM_RESERVED, we have a problem.
380 */
381 if (unlikely(!pfn_valid(pfn))) {
382 print_bad_pte(vma, pte, addr);
383 goto out_set_pte; /* try to do something sane */
384 }
385
386 page = pfn_to_page(pfn);
387
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 /*
389 * If it's a COW mapping, write protect it both
390 * in the parent and the child
391 */
392 if ((vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE) {
393 ptep_set_wrprotect(src_mm, addr, src_pte);
394 pte = *src_pte;
395 }
396
397 /*
398 * If it's a shared mapping, mark it clean in
399 * the child
400 */
401 if (vm_flags & VM_SHARED)
402 pte = pte_mkclean(pte);
403 pte = pte_mkold(pte);
404 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 page_dup_rmap(page);
Hugh Dickins8c103762005-10-29 18:16:13 -0700406 rss[!!PageAnon(page)]++;
Hugh Dickinsae859762005-10-29 18:16:05 -0700407
408out_set_pte:
409 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410}
411
412static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
413 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
414 unsigned long addr, unsigned long end)
415{
416 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700417 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700418 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700419 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420
421again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700422 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700423 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 if (!dst_pte)
425 return -ENOMEM;
426 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700427 src_ptl = &src_mm->page_table_lock;
428 spin_lock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 do {
431 /*
432 * We are holding two locks at this point - either of them
433 * could generate latencies in another task on another CPU.
434 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700435 if (progress >= 32) {
436 progress = 0;
437 if (need_resched() ||
Hugh Dickinsc74df322005-10-29 18:16:23 -0700438 need_lockbreak(src_ptl) ||
439 need_lockbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700440 break;
441 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 if (pte_none(*src_pte)) {
443 progress++;
444 continue;
445 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700446 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 progress += 8;
448 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449
Hugh Dickinsc74df322005-10-29 18:16:23 -0700450 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700452 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700453 pte_unmap_unlock(dst_pte - 1, dst_ptl);
454 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 if (addr != end)
456 goto again;
457 return 0;
458}
459
460static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
461 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
462 unsigned long addr, unsigned long end)
463{
464 pmd_t *src_pmd, *dst_pmd;
465 unsigned long next;
466
467 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
468 if (!dst_pmd)
469 return -ENOMEM;
470 src_pmd = pmd_offset(src_pud, addr);
471 do {
472 next = pmd_addr_end(addr, end);
473 if (pmd_none_or_clear_bad(src_pmd))
474 continue;
475 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
476 vma, addr, next))
477 return -ENOMEM;
478 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
479 return 0;
480}
481
482static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
483 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
484 unsigned long addr, unsigned long end)
485{
486 pud_t *src_pud, *dst_pud;
487 unsigned long next;
488
489 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
490 if (!dst_pud)
491 return -ENOMEM;
492 src_pud = pud_offset(src_pgd, addr);
493 do {
494 next = pud_addr_end(addr, end);
495 if (pud_none_or_clear_bad(src_pud))
496 continue;
497 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
498 vma, addr, next))
499 return -ENOMEM;
500 } while (dst_pud++, src_pud++, addr = next, addr != end);
501 return 0;
502}
503
504int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
505 struct vm_area_struct *vma)
506{
507 pgd_t *src_pgd, *dst_pgd;
508 unsigned long next;
509 unsigned long addr = vma->vm_start;
510 unsigned long end = vma->vm_end;
511
Nick Piggind9928952005-08-28 16:49:11 +1000512 /*
513 * Don't copy ptes where a page fault will fill them correctly.
514 * Fork becomes much lighter when there are big shared or private
515 * readonly mappings. The tradeoff is that copy_page_range is more
516 * efficient than faulting.
517 */
518 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) {
519 if (!vma->anon_vma)
520 return 0;
521 }
522
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 if (is_vm_hugetlb_page(vma))
524 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
525
526 dst_pgd = pgd_offset(dst_mm, addr);
527 src_pgd = pgd_offset(src_mm, addr);
528 do {
529 next = pgd_addr_end(addr, end);
530 if (pgd_none_or_clear_bad(src_pgd))
531 continue;
532 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
533 vma, addr, next))
534 return -ENOMEM;
535 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
536 return 0;
537}
538
Nick Pigginb5810032005-10-29 18:16:12 -0700539static void zap_pte_range(struct mmu_gather *tlb,
540 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 unsigned long addr, unsigned long end,
542 struct zap_details *details)
543{
Nick Pigginb5810032005-10-29 18:16:12 -0700544 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 pte_t *pte;
Hugh Dickinsae859762005-10-29 18:16:05 -0700546 int file_rss = 0;
547 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548
549 pte = pte_offset_map(pmd, addr);
550 do {
551 pte_t ptent = *pte;
552 if (pte_none(ptent))
553 continue;
554 if (pte_present(ptent)) {
555 struct page *page = NULL;
Nick Pigginb5810032005-10-29 18:16:12 -0700556 if (!(vma->vm_flags & VM_RESERVED)) {
557 unsigned long pfn = pte_pfn(ptent);
558 if (unlikely(!pfn_valid(pfn)))
559 print_bad_pte(vma, ptent, addr);
560 else
561 page = pfn_to_page(pfn);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 }
563 if (unlikely(details) && page) {
564 /*
565 * unmap_shared_mapping_pages() wants to
566 * invalidate cache without truncating:
567 * unmap shared but keep private pages.
568 */
569 if (details->check_mapping &&
570 details->check_mapping != page->mapping)
571 continue;
572 /*
573 * Each page->index must be checked when
574 * invalidating or truncating nonlinear.
575 */
576 if (details->nonlinear_vma &&
577 (page->index < details->first_index ||
578 page->index > details->last_index))
579 continue;
580 }
Nick Pigginb5810032005-10-29 18:16:12 -0700581 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700582 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 tlb_remove_tlb_entry(tlb, pte, addr);
584 if (unlikely(!page))
585 continue;
586 if (unlikely(details) && details->nonlinear_vma
587 && linear_page_index(details->nonlinear_vma,
588 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700589 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700592 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700593 else {
594 if (pte_dirty(ptent))
595 set_page_dirty(page);
596 if (pte_young(ptent))
597 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700598 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700599 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 page_remove_rmap(page);
601 tlb_remove_page(tlb, page);
602 continue;
603 }
604 /*
605 * If details->check_mapping, we leave swap entries;
606 * if details->nonlinear_vma, we leave file entries.
607 */
608 if (unlikely(details))
609 continue;
610 if (!pte_file(ptent))
611 free_swap_and_cache(pte_to_swp_entry(ptent));
Nick Pigginb5810032005-10-29 18:16:12 -0700612 pte_clear_full(mm, addr, pte, tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsae859762005-10-29 18:16:05 -0700614
Hugh Dickins86d912f2005-10-29 18:16:14 -0700615 add_mm_rss(mm, file_rss, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 pte_unmap(pte - 1);
617}
618
Nick Pigginb5810032005-10-29 18:16:12 -0700619static inline void zap_pmd_range(struct mmu_gather *tlb,
620 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 unsigned long addr, unsigned long end,
622 struct zap_details *details)
623{
624 pmd_t *pmd;
625 unsigned long next;
626
627 pmd = pmd_offset(pud, addr);
628 do {
629 next = pmd_addr_end(addr, end);
630 if (pmd_none_or_clear_bad(pmd))
631 continue;
Nick Pigginb5810032005-10-29 18:16:12 -0700632 zap_pte_range(tlb, vma, pmd, addr, next, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 } while (pmd++, addr = next, addr != end);
634}
635
Nick Pigginb5810032005-10-29 18:16:12 -0700636static inline void zap_pud_range(struct mmu_gather *tlb,
637 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 unsigned long addr, unsigned long end,
639 struct zap_details *details)
640{
641 pud_t *pud;
642 unsigned long next;
643
644 pud = pud_offset(pgd, addr);
645 do {
646 next = pud_addr_end(addr, end);
647 if (pud_none_or_clear_bad(pud))
648 continue;
Nick Pigginb5810032005-10-29 18:16:12 -0700649 zap_pmd_range(tlb, vma, pud, addr, next, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 } while (pud++, addr = next, addr != end);
651}
652
653static void unmap_page_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
654 unsigned long addr, unsigned long end,
655 struct zap_details *details)
656{
657 pgd_t *pgd;
658 unsigned long next;
659
660 if (details && !details->check_mapping && !details->nonlinear_vma)
661 details = NULL;
662
663 BUG_ON(addr >= end);
664 tlb_start_vma(tlb, vma);
665 pgd = pgd_offset(vma->vm_mm, addr);
666 do {
667 next = pgd_addr_end(addr, end);
668 if (pgd_none_or_clear_bad(pgd))
669 continue;
Nick Pigginb5810032005-10-29 18:16:12 -0700670 zap_pud_range(tlb, vma, pgd, addr, next, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 } while (pgd++, addr = next, addr != end);
672 tlb_end_vma(tlb, vma);
673}
674
675#ifdef CONFIG_PREEMPT
676# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
677#else
678/* No preempt: go for improved straight-line efficiency */
679# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
680#endif
681
682/**
683 * unmap_vmas - unmap a range of memory covered by a list of vma's
684 * @tlbp: address of the caller's struct mmu_gather
685 * @mm: the controlling mm_struct
686 * @vma: the starting vma
687 * @start_addr: virtual address at which to start unmapping
688 * @end_addr: virtual address at which to end unmapping
689 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
690 * @details: details of nonlinear truncation or shared cache invalidation
691 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700692 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 *
694 * Unmap all pages in the vma list. Called under page_table_lock.
695 *
696 * We aim to not hold page_table_lock for too long (for scheduling latency
697 * reasons). So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
698 * return the ending mmu_gather to the caller.
699 *
700 * Only addresses between `start' and `end' will be unmapped.
701 *
702 * The VMA list must be sorted in ascending virtual address order.
703 *
704 * unmap_vmas() assumes that the caller will flush the whole unmapped address
705 * range after unmap_vmas() returns. So the only responsibility here is to
706 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
707 * drops the lock and schedules.
708 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700709unsigned long unmap_vmas(struct mmu_gather **tlbp, struct mm_struct *mm,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710 struct vm_area_struct *vma, unsigned long start_addr,
711 unsigned long end_addr, unsigned long *nr_accounted,
712 struct zap_details *details)
713{
714 unsigned long zap_bytes = ZAP_BLOCK_SIZE;
715 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
716 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700717 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700719 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720
721 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 unsigned long end;
723
724 start = max(vma->vm_start, start_addr);
725 if (start >= vma->vm_end)
726 continue;
727 end = min(vma->vm_end, end_addr);
728 if (end <= vma->vm_start)
729 continue;
730
731 if (vma->vm_flags & VM_ACCOUNT)
732 *nr_accounted += (end - start) >> PAGE_SHIFT;
733
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 while (start != end) {
735 unsigned long block;
736
737 if (!tlb_start_valid) {
738 tlb_start = start;
739 tlb_start_valid = 1;
740 }
741
742 if (is_vm_hugetlb_page(vma)) {
743 block = end - start;
744 unmap_hugepage_range(vma, start, end);
745 } else {
746 block = min(zap_bytes, end - start);
747 unmap_page_range(*tlbp, vma, start,
748 start + block, details);
749 }
750
751 start += block;
752 zap_bytes -= block;
753 if ((long)zap_bytes > 0)
754 continue;
755
756 tlb_finish_mmu(*tlbp, tlb_start, start);
757
758 if (need_resched() ||
759 need_lockbreak(&mm->page_table_lock) ||
760 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
761 if (i_mmap_lock) {
762 /* must reset count of rss freed */
763 *tlbp = tlb_gather_mmu(mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764 goto out;
765 }
766 spin_unlock(&mm->page_table_lock);
767 cond_resched();
768 spin_lock(&mm->page_table_lock);
769 }
770
771 *tlbp = tlb_gather_mmu(mm, fullmm);
772 tlb_start_valid = 0;
773 zap_bytes = ZAP_BLOCK_SIZE;
774 }
775 }
776out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700777 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778}
779
780/**
781 * zap_page_range - remove user pages in a given range
782 * @vma: vm_area_struct holding the applicable pages
783 * @address: starting address of pages to zap
784 * @size: number of bytes to zap
785 * @details: details of nonlinear truncation or shared cache invalidation
786 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700787unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 unsigned long size, struct zap_details *details)
789{
790 struct mm_struct *mm = vma->vm_mm;
791 struct mmu_gather *tlb;
792 unsigned long end = address + size;
793 unsigned long nr_accounted = 0;
794
795 if (is_vm_hugetlb_page(vma)) {
796 zap_hugepage_range(vma, address, size);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700797 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 }
799
800 lru_add_drain();
801 spin_lock(&mm->page_table_lock);
802 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700803 update_hiwater_rss(mm);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700804 end = unmap_vmas(&tlb, mm, vma, address, end, &nr_accounted, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700805 tlb_finish_mmu(tlb, address, end);
806 spin_unlock(&mm->page_table_lock);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700807 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808}
809
810/*
811 * Do a quick page-table lookup for a single page.
812 * mm->page_table_lock must be held.
813 */
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700814static struct page *__follow_page(struct mm_struct *mm, unsigned long address,
815 int read, int write, int accessed)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816{
817 pgd_t *pgd;
818 pud_t *pud;
819 pmd_t *pmd;
820 pte_t *ptep, pte;
821 unsigned long pfn;
822 struct page *page;
823
824 page = follow_huge_addr(mm, address, write);
825 if (! IS_ERR(page))
826 return page;
827
828 pgd = pgd_offset(mm, address);
829 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
830 goto out;
831
832 pud = pud_offset(pgd, address);
833 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
834 goto out;
835
836 pmd = pmd_offset(pud, address);
837 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
838 goto out;
839 if (pmd_huge(*pmd))
840 return follow_huge_pmd(mm, address, pmd, write);
841
842 ptep = pte_offset_map(pmd, address);
843 if (!ptep)
844 goto out;
845
846 pte = *ptep;
847 pte_unmap(ptep);
848 if (pte_present(pte)) {
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000849 if (write && !pte_write(pte))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 goto out;
851 if (read && !pte_read(pte))
852 goto out;
853 pfn = pte_pfn(pte);
854 if (pfn_valid(pfn)) {
855 page = pfn_to_page(pfn);
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000856 if (accessed) {
857 if (write && !pte_dirty(pte) &&!PageDirty(page))
858 set_page_dirty(page);
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700859 mark_page_accessed(page);
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000860 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 return page;
862 }
863 }
864
865out:
866 return NULL;
867}
868
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700869inline struct page *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700870follow_page(struct mm_struct *mm, unsigned long address, int write)
871{
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700872 return __follow_page(mm, address, 0, write, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873}
874
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700875/*
876 * check_user_page_readable() can be called frm niterrupt context by oprofile,
877 * so we need to avoid taking any non-irq-safe locks
878 */
879int check_user_page_readable(struct mm_struct *mm, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880{
Andrew Morton1aaf18f2005-07-27 11:43:54 -0700881 return __follow_page(mm, address, 1, 0, 0) != NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883EXPORT_SYMBOL(check_user_page_readable);
884
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885static inline int
886untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma,
887 unsigned long address)
888{
889 pgd_t *pgd;
890 pud_t *pud;
891 pmd_t *pmd;
892
893 /* Check if the vma is for an anonymous mapping. */
894 if (vma->vm_ops && vma->vm_ops->nopage)
895 return 0;
896
897 /* Check if page directory entry exists. */
898 pgd = pgd_offset(mm, address);
899 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
900 return 1;
901
902 pud = pud_offset(pgd, address);
903 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
904 return 1;
905
906 /* Check if page middle directory entry exists. */
907 pmd = pmd_offset(pud, address);
908 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
909 return 1;
910
911 /* There is a pte slot for 'address' in 'mm'. */
912 return 0;
913}
914
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
916 unsigned long start, int len, int write, int force,
917 struct page **pages, struct vm_area_struct **vmas)
918{
919 int i;
920 unsigned int flags;
921
922 /*
923 * Require read or write permissions.
924 * If 'force' is set, we only require the "MAY" flags.
925 */
926 flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
927 flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
928 i = 0;
929
930 do {
931 struct vm_area_struct * vma;
932
933 vma = find_extend_vma(mm, start);
934 if (!vma && in_gate_area(tsk, start)) {
935 unsigned long pg = start & PAGE_MASK;
936 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
937 pgd_t *pgd;
938 pud_t *pud;
939 pmd_t *pmd;
940 pte_t *pte;
941 if (write) /* user gate pages are read-only */
942 return i ? : -EFAULT;
943 if (pg > TASK_SIZE)
944 pgd = pgd_offset_k(pg);
945 else
946 pgd = pgd_offset_gate(mm, pg);
947 BUG_ON(pgd_none(*pgd));
948 pud = pud_offset(pgd, pg);
949 BUG_ON(pud_none(*pud));
950 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700951 if (pmd_none(*pmd))
952 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700954 if (pte_none(*pte)) {
955 pte_unmap(pte);
956 return i ? : -EFAULT;
957 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 if (pages) {
959 pages[i] = pte_page(*pte);
960 get_page(pages[i]);
961 }
962 pte_unmap(pte);
963 if (vmas)
964 vmas[i] = gate_vma;
965 i++;
966 start += PAGE_SIZE;
967 len--;
968 continue;
969 }
970
Nick Pigginb5810032005-10-29 18:16:12 -0700971 if (!vma || (vma->vm_flags & (VM_IO | VM_RESERVED))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972 || !(flags & vma->vm_flags))
973 return i ? : -EFAULT;
974
975 if (is_vm_hugetlb_page(vma)) {
976 i = follow_hugetlb_page(mm, vma, pages, vmas,
977 &start, &len, i);
978 continue;
979 }
980 spin_lock(&mm->page_table_lock);
981 do {
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000982 int write_access = write;
Hugh Dickins08ef4722005-06-21 17:15:10 -0700983 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700984
985 cond_resched_lock(&mm->page_table_lock);
Nick Pigginf33ea7f2005-08-03 20:24:01 +1000986 while (!(page = follow_page(mm, start, write_access))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -0700987 int ret;
988
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 /*
990 * Shortcut for anonymous pages. We don't want
991 * to force the creation of pages tables for
Hugh Dickins08ef4722005-06-21 17:15:10 -0700992 * insanely big anonymously mapped areas that
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 * nobody touched so far. This is important
994 * for doing a core dump for these mappings.
995 */
Linus Torvalds4ceb5db2005-08-01 11:14:49 -0700996 if (!write && untouched_anonymous_page(mm,vma,start)) {
Hugh Dickins08ef4722005-06-21 17:15:10 -0700997 page = ZERO_PAGE(start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998 break;
999 }
1000 spin_unlock(&mm->page_table_lock);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001001 ret = __handle_mm_fault(mm, vma, start, write_access);
1002
1003 /*
1004 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1005 * broken COW when necessary, even if maybe_mkwrite
1006 * decided not to set pte_write. We can thus safely do
1007 * subsequent page lookups as if they were reads.
1008 */
1009 if (ret & VM_FAULT_WRITE)
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001010 write_access = 0;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001011
1012 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 case VM_FAULT_MINOR:
1014 tsk->min_flt++;
1015 break;
1016 case VM_FAULT_MAJOR:
1017 tsk->maj_flt++;
1018 break;
1019 case VM_FAULT_SIGBUS:
1020 return i ? i : -EFAULT;
1021 case VM_FAULT_OOM:
1022 return i ? i : -ENOMEM;
1023 default:
1024 BUG();
1025 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001026 spin_lock(&mm->page_table_lock);
1027 }
1028 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001029 pages[i] = page;
1030 flush_dcache_page(page);
Nick Pigginb5810032005-10-29 18:16:12 -07001031 page_cache_get(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 }
1033 if (vmas)
1034 vmas[i] = vma;
1035 i++;
1036 start += PAGE_SIZE;
1037 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001038 } while (len && start < vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 spin_unlock(&mm->page_table_lock);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001040 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 return i;
1042}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043EXPORT_SYMBOL(get_user_pages);
1044
1045static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1046 unsigned long addr, unsigned long end, pgprot_t prot)
1047{
1048 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001049 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050
Hugh Dickinsc74df322005-10-29 18:16:23 -07001051 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052 if (!pte)
1053 return -ENOMEM;
1054 do {
Nick Pigginb5810032005-10-29 18:16:12 -07001055 struct page *page = ZERO_PAGE(addr);
1056 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1057 page_cache_get(page);
1058 page_add_file_rmap(page);
1059 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 BUG_ON(!pte_none(*pte));
1061 set_pte_at(mm, addr, pte, zero_pte);
1062 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001063 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 return 0;
1065}
1066
1067static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1068 unsigned long addr, unsigned long end, pgprot_t prot)
1069{
1070 pmd_t *pmd;
1071 unsigned long next;
1072
1073 pmd = pmd_alloc(mm, pud, addr);
1074 if (!pmd)
1075 return -ENOMEM;
1076 do {
1077 next = pmd_addr_end(addr, end);
1078 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1079 return -ENOMEM;
1080 } while (pmd++, addr = next, addr != end);
1081 return 0;
1082}
1083
1084static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1085 unsigned long addr, unsigned long end, pgprot_t prot)
1086{
1087 pud_t *pud;
1088 unsigned long next;
1089
1090 pud = pud_alloc(mm, pgd, addr);
1091 if (!pud)
1092 return -ENOMEM;
1093 do {
1094 next = pud_addr_end(addr, end);
1095 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1096 return -ENOMEM;
1097 } while (pud++, addr = next, addr != end);
1098 return 0;
1099}
1100
1101int zeromap_page_range(struct vm_area_struct *vma,
1102 unsigned long addr, unsigned long size, pgprot_t prot)
1103{
1104 pgd_t *pgd;
1105 unsigned long next;
1106 unsigned long end = addr + size;
1107 struct mm_struct *mm = vma->vm_mm;
1108 int err;
1109
1110 BUG_ON(addr >= end);
1111 pgd = pgd_offset(mm, addr);
1112 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 do {
1114 next = pgd_addr_end(addr, end);
1115 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1116 if (err)
1117 break;
1118 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 return err;
1120}
1121
1122/*
1123 * maps a range of physical memory into the requested pages. the old
1124 * mappings are removed. any references to nonexistent pages results
1125 * in null mappings (currently treated as "copy-on-access")
1126 */
1127static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1128 unsigned long addr, unsigned long end,
1129 unsigned long pfn, pgprot_t prot)
1130{
1131 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001132 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133
Hugh Dickinsc74df322005-10-29 18:16:23 -07001134 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 if (!pte)
1136 return -ENOMEM;
1137 do {
1138 BUG_ON(!pte_none(*pte));
Nick Pigginb5810032005-10-29 18:16:12 -07001139 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001140 pfn++;
1141 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001142 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001143 return 0;
1144}
1145
1146static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1147 unsigned long addr, unsigned long end,
1148 unsigned long pfn, pgprot_t prot)
1149{
1150 pmd_t *pmd;
1151 unsigned long next;
1152
1153 pfn -= addr >> PAGE_SHIFT;
1154 pmd = pmd_alloc(mm, pud, addr);
1155 if (!pmd)
1156 return -ENOMEM;
1157 do {
1158 next = pmd_addr_end(addr, end);
1159 if (remap_pte_range(mm, pmd, addr, next,
1160 pfn + (addr >> PAGE_SHIFT), prot))
1161 return -ENOMEM;
1162 } while (pmd++, addr = next, addr != end);
1163 return 0;
1164}
1165
1166static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1167 unsigned long addr, unsigned long end,
1168 unsigned long pfn, pgprot_t prot)
1169{
1170 pud_t *pud;
1171 unsigned long next;
1172
1173 pfn -= addr >> PAGE_SHIFT;
1174 pud = pud_alloc(mm, pgd, addr);
1175 if (!pud)
1176 return -ENOMEM;
1177 do {
1178 next = pud_addr_end(addr, end);
1179 if (remap_pmd_range(mm, pud, addr, next,
1180 pfn + (addr >> PAGE_SHIFT), prot))
1181 return -ENOMEM;
1182 } while (pud++, addr = next, addr != end);
1183 return 0;
1184}
1185
1186/* Note: this is only safe if the mm semaphore is held when called. */
1187int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1188 unsigned long pfn, unsigned long size, pgprot_t prot)
1189{
1190 pgd_t *pgd;
1191 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001192 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001193 struct mm_struct *mm = vma->vm_mm;
1194 int err;
1195
1196 /*
1197 * Physically remapped pages are special. Tell the
1198 * rest of the world about it:
1199 * VM_IO tells people not to look at these pages
1200 * (accesses can have side effects).
Nick Pigginb5810032005-10-29 18:16:12 -07001201 * VM_RESERVED tells the core MM not to "manage" these pages
1202 * (e.g. refcount, mapcount, try to swap them out).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001203 */
1204 vma->vm_flags |= VM_IO | VM_RESERVED;
1205
1206 BUG_ON(addr >= end);
1207 pfn -= addr >> PAGE_SHIFT;
1208 pgd = pgd_offset(mm, addr);
1209 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001210 do {
1211 next = pgd_addr_end(addr, end);
1212 err = remap_pud_range(mm, pgd, addr, next,
1213 pfn + (addr >> PAGE_SHIFT), prot);
1214 if (err)
1215 break;
1216 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 return err;
1218}
1219EXPORT_SYMBOL(remap_pfn_range);
1220
1221/*
1222 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1223 * servicing faults for write access. In the normal case, do always want
1224 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1225 * that do not have writing enabled, when used by access_process_vm.
1226 */
1227static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1228{
1229 if (likely(vma->vm_flags & VM_WRITE))
1230 pte = pte_mkwrite(pte);
1231 return pte;
1232}
1233
1234/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001235 * This routine handles present pages, when users try to write
1236 * to a shared page. It is done by copying the page to a new address
1237 * and decrementing the shared-page counter for the old page.
1238 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239 * Note that this routine assumes that the protection checks have been
1240 * done by the caller (the low-level page fault routine in most cases).
1241 * Thus we can safely just mark it writable once we've done any necessary
1242 * COW.
1243 *
1244 * We also mark the page dirty at this point even though the page will
1245 * change only once the write actually happens. This avoids a few races,
1246 * and potentially makes it more efficient.
1247 *
1248 * We hold the mm semaphore and the page_table_lock on entry and exit
1249 * with the page_table_lock released.
1250 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001251static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1252 unsigned long address, pte_t *page_table, pmd_t *pmd,
1253 pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254{
1255 struct page *old_page, *new_page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001256 unsigned long pfn = pte_pfn(orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 pte_t entry;
Hugh Dickins65500d22005-10-29 18:15:59 -07001258 int ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259
Nick Pigginb5810032005-10-29 18:16:12 -07001260 BUG_ON(vma->vm_flags & VM_RESERVED);
1261
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 if (unlikely(!pfn_valid(pfn))) {
1263 /*
Hugh Dickins65500d22005-10-29 18:15:59 -07001264 * Page table corrupted: show pte and kill process.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 */
Nick Pigginb5810032005-10-29 18:16:12 -07001266 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07001267 ret = VM_FAULT_OOM;
1268 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 }
1270 old_page = pfn_to_page(pfn);
1271
Hugh Dickinsd296e9c2005-06-21 17:15:11 -07001272 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001273 int reuse = can_share_swap_page(old_page);
1274 unlock_page(old_page);
1275 if (reuse) {
1276 flush_cache_page(vma, address, pfn);
Hugh Dickins65500d22005-10-29 18:15:59 -07001277 entry = pte_mkyoung(orig_pte);
1278 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001279 ptep_set_access_flags(vma, address, page_table, entry, 1);
1280 update_mmu_cache(vma, address, entry);
1281 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001282 ret |= VM_FAULT_WRITE;
1283 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284 }
1285 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001286
1287 /*
1288 * Ok, we need to copy. Oh, well..
1289 */
Nick Pigginb5810032005-10-29 18:16:12 -07001290 page_cache_get(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001291 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001292 spin_unlock(&mm->page_table_lock);
1293
1294 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001295 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001296 if (old_page == ZERO_PAGE(address)) {
1297 new_page = alloc_zeroed_user_highpage(vma, address);
1298 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001299 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001300 } else {
1301 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1302 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001303 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 copy_user_highpage(new_page, old_page, address);
1305 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001306
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307 /*
1308 * Re-check the pte - we dropped the lock
1309 */
1310 spin_lock(&mm->page_table_lock);
1311 page_table = pte_offset_map(pmd, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07001312 if (likely(pte_same(*page_table, orig_pte))) {
Nick Pigginb5810032005-10-29 18:16:12 -07001313 page_remove_rmap(old_page);
1314 if (!PageAnon(old_page)) {
Hugh Dickins42946212005-10-29 18:16:05 -07001315 inc_mm_counter(mm, anon_rss);
Nick Pigginb5810032005-10-29 18:16:12 -07001316 dec_mm_counter(mm, file_rss);
Hugh Dickins42946212005-10-29 18:16:05 -07001317 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001318 flush_cache_page(vma, address, pfn);
Hugh Dickins65500d22005-10-29 18:15:59 -07001319 entry = mk_pte(new_page, vma->vm_page_prot);
1320 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1321 ptep_establish(vma, address, page_table, entry);
1322 update_mmu_cache(vma, address, entry);
1323 lazy_mmu_prot_update(entry);
1324
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 lru_cache_add_active(new_page);
1326 page_add_anon_rmap(new_page, vma, address);
1327
1328 /* Free the old page.. */
1329 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001330 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001331 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332 page_cache_release(new_page);
1333 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001334unlock:
1335 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001336 spin_unlock(&mm->page_table_lock);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001337 return ret;
Hugh Dickins65500d22005-10-29 18:15:59 -07001338oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339 page_cache_release(old_page);
1340 return VM_FAULT_OOM;
1341}
1342
1343/*
1344 * Helper functions for unmap_mapping_range().
1345 *
1346 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1347 *
1348 * We have to restart searching the prio_tree whenever we drop the lock,
1349 * since the iterator is only valid while the lock is held, and anyway
1350 * a later vma might be split and reinserted earlier while lock dropped.
1351 *
1352 * The list of nonlinear vmas could be handled more efficiently, using
1353 * a placeholder, but handle it in the same way until a need is shown.
1354 * It is important to search the prio_tree before nonlinear list: a vma
1355 * may become nonlinear and be shifted from prio_tree to nonlinear list
1356 * while the lock is dropped; but never shifted from list to prio_tree.
1357 *
1358 * In order to make forward progress despite restarting the search,
1359 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1360 * quickly skip it next time around. Since the prio_tree search only
1361 * shows us those vmas affected by unmapping the range in question, we
1362 * can't efficiently keep all vmas in step with mapping->truncate_count:
1363 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1364 * mapping->truncate_count and vma->vm_truncate_count are protected by
1365 * i_mmap_lock.
1366 *
1367 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001368 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001369 * and restart from that address when we reach that vma again. It might
1370 * have been split or merged, shrunk or extended, but never shifted: so
1371 * restart_addr remains valid so long as it remains in the vma's range.
1372 * unmap_mapping_range forces truncate_count to leap over page-aligned
1373 * values so we can save vma's restart_addr in its truncate_count field.
1374 */
1375#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1376
1377static void reset_vma_truncate_counts(struct address_space *mapping)
1378{
1379 struct vm_area_struct *vma;
1380 struct prio_tree_iter iter;
1381
1382 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1383 vma->vm_truncate_count = 0;
1384 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1385 vma->vm_truncate_count = 0;
1386}
1387
1388static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1389 unsigned long start_addr, unsigned long end_addr,
1390 struct zap_details *details)
1391{
1392 unsigned long restart_addr;
1393 int need_break;
1394
1395again:
1396 restart_addr = vma->vm_truncate_count;
1397 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1398 start_addr = restart_addr;
1399 if (start_addr >= end_addr) {
1400 /* Top of vma has been split off since last time */
1401 vma->vm_truncate_count = details->truncate_count;
1402 return 0;
1403 }
1404 }
1405
Hugh Dickinsee39b372005-04-19 13:29:15 -07001406 restart_addr = zap_page_range(vma, start_addr,
1407 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001408
1409 /*
1410 * We cannot rely on the break test in unmap_vmas:
1411 * on the one hand, we don't want to restart our loop
1412 * just because that broke out for the page_table_lock;
1413 * on the other hand, it does no test when vma is small.
1414 */
1415 need_break = need_resched() ||
1416 need_lockbreak(details->i_mmap_lock);
1417
Hugh Dickinsee39b372005-04-19 13:29:15 -07001418 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 /* We have now completed this vma: mark it so */
1420 vma->vm_truncate_count = details->truncate_count;
1421 if (!need_break)
1422 return 0;
1423 } else {
1424 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001425 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426 if (!need_break)
1427 goto again;
1428 }
1429
1430 spin_unlock(details->i_mmap_lock);
1431 cond_resched();
1432 spin_lock(details->i_mmap_lock);
1433 return -EINTR;
1434}
1435
1436static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1437 struct zap_details *details)
1438{
1439 struct vm_area_struct *vma;
1440 struct prio_tree_iter iter;
1441 pgoff_t vba, vea, zba, zea;
1442
1443restart:
1444 vma_prio_tree_foreach(vma, &iter, root,
1445 details->first_index, details->last_index) {
1446 /* Skip quickly over those we have already dealt with */
1447 if (vma->vm_truncate_count == details->truncate_count)
1448 continue;
1449
1450 vba = vma->vm_pgoff;
1451 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1452 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1453 zba = details->first_index;
1454 if (zba < vba)
1455 zba = vba;
1456 zea = details->last_index;
1457 if (zea > vea)
1458 zea = vea;
1459
1460 if (unmap_mapping_range_vma(vma,
1461 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1462 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1463 details) < 0)
1464 goto restart;
1465 }
1466}
1467
1468static inline void unmap_mapping_range_list(struct list_head *head,
1469 struct zap_details *details)
1470{
1471 struct vm_area_struct *vma;
1472
1473 /*
1474 * In nonlinear VMAs there is no correspondence between virtual address
1475 * offset and file offset. So we must perform an exhaustive search
1476 * across *all* the pages in each nonlinear VMA, not just the pages
1477 * whose virtual address lies outside the file truncation point.
1478 */
1479restart:
1480 list_for_each_entry(vma, head, shared.vm_set.list) {
1481 /* Skip quickly over those we have already dealt with */
1482 if (vma->vm_truncate_count == details->truncate_count)
1483 continue;
1484 details->nonlinear_vma = vma;
1485 if (unmap_mapping_range_vma(vma, vma->vm_start,
1486 vma->vm_end, details) < 0)
1487 goto restart;
1488 }
1489}
1490
1491/**
1492 * unmap_mapping_range - unmap the portion of all mmaps
1493 * in the specified address_space corresponding to the specified
1494 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001495 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 * @holebegin: byte in first page to unmap, relative to the start of
1497 * the underlying file. This will be rounded down to a PAGE_SIZE
1498 * boundary. Note that this is different from vmtruncate(), which
1499 * must keep the partial page. In contrast, we must get rid of
1500 * partial pages.
1501 * @holelen: size of prospective hole in bytes. This will be rounded
1502 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1503 * end of the file.
1504 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1505 * but 0 when invalidating pagecache, don't throw away private data.
1506 */
1507void unmap_mapping_range(struct address_space *mapping,
1508 loff_t const holebegin, loff_t const holelen, int even_cows)
1509{
1510 struct zap_details details;
1511 pgoff_t hba = holebegin >> PAGE_SHIFT;
1512 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1513
1514 /* Check for overflow. */
1515 if (sizeof(holelen) > sizeof(hlen)) {
1516 long long holeend =
1517 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1518 if (holeend & ~(long long)ULONG_MAX)
1519 hlen = ULONG_MAX - hba + 1;
1520 }
1521
1522 details.check_mapping = even_cows? NULL: mapping;
1523 details.nonlinear_vma = NULL;
1524 details.first_index = hba;
1525 details.last_index = hba + hlen - 1;
1526 if (details.last_index < details.first_index)
1527 details.last_index = ULONG_MAX;
1528 details.i_mmap_lock = &mapping->i_mmap_lock;
1529
1530 spin_lock(&mapping->i_mmap_lock);
1531
1532 /* serialize i_size write against truncate_count write */
1533 smp_wmb();
1534 /* Protect against page faults, and endless unmapping loops */
1535 mapping->truncate_count++;
1536 /*
1537 * For archs where spin_lock has inclusive semantics like ia64
1538 * this smp_mb() will prevent to read pagetable contents
1539 * before the truncate_count increment is visible to
1540 * other cpus.
1541 */
1542 smp_mb();
1543 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1544 if (mapping->truncate_count == 0)
1545 reset_vma_truncate_counts(mapping);
1546 mapping->truncate_count++;
1547 }
1548 details.truncate_count = mapping->truncate_count;
1549
1550 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1551 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1552 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1553 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1554 spin_unlock(&mapping->i_mmap_lock);
1555}
1556EXPORT_SYMBOL(unmap_mapping_range);
1557
1558/*
1559 * Handle all mappings that got truncated by a "truncate()"
1560 * system call.
1561 *
1562 * NOTE! We have to be ready to update the memory sharing
1563 * between the file and the memory map for a potential last
1564 * incomplete page. Ugly, but necessary.
1565 */
1566int vmtruncate(struct inode * inode, loff_t offset)
1567{
1568 struct address_space *mapping = inode->i_mapping;
1569 unsigned long limit;
1570
1571 if (inode->i_size < offset)
1572 goto do_expand;
1573 /*
1574 * truncation of in-use swapfiles is disallowed - it would cause
1575 * subsequent swapout to scribble on the now-freed blocks.
1576 */
1577 if (IS_SWAPFILE(inode))
1578 goto out_busy;
1579 i_size_write(inode, offset);
1580 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1581 truncate_inode_pages(mapping, offset);
1582 goto out_truncate;
1583
1584do_expand:
1585 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1586 if (limit != RLIM_INFINITY && offset > limit)
1587 goto out_sig;
1588 if (offset > inode->i_sb->s_maxbytes)
1589 goto out_big;
1590 i_size_write(inode, offset);
1591
1592out_truncate:
1593 if (inode->i_op && inode->i_op->truncate)
1594 inode->i_op->truncate(inode);
1595 return 0;
1596out_sig:
1597 send_sig(SIGXFSZ, current, 0);
1598out_big:
1599 return -EFBIG;
1600out_busy:
1601 return -ETXTBSY;
1602}
1603
1604EXPORT_SYMBOL(vmtruncate);
1605
1606/*
1607 * Primitive swap readahead code. We simply read an aligned block of
1608 * (1 << page_cluster) entries in the swap area. This method is chosen
1609 * because it doesn't cost us any seek time. We also make sure to queue
1610 * the 'original' request together with the readahead ones...
1611 *
1612 * This has been extended to use the NUMA policies from the mm triggering
1613 * the readahead.
1614 *
1615 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1616 */
1617void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1618{
1619#ifdef CONFIG_NUMA
1620 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1621#endif
1622 int i, num;
1623 struct page *new_page;
1624 unsigned long offset;
1625
1626 /*
1627 * Get the number of handles we should do readahead io to.
1628 */
1629 num = valid_swaphandles(entry, &offset);
1630 for (i = 0; i < num; offset++, i++) {
1631 /* Ok, do the async read-ahead now */
1632 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1633 offset), vma, addr);
1634 if (!new_page)
1635 break;
1636 page_cache_release(new_page);
1637#ifdef CONFIG_NUMA
1638 /*
1639 * Find the next applicable VMA for the NUMA policy.
1640 */
1641 addr += PAGE_SIZE;
1642 if (addr == 0)
1643 vma = NULL;
1644 if (vma) {
1645 if (addr >= vma->vm_end) {
1646 vma = next_vma;
1647 next_vma = vma ? vma->vm_next : NULL;
1648 }
1649 if (vma && addr < vma->vm_start)
1650 vma = NULL;
1651 } else {
1652 if (next_vma && addr >= next_vma->vm_start) {
1653 vma = next_vma;
1654 next_vma = vma->vm_next;
1655 }
1656 }
1657#endif
1658 }
1659 lru_add_drain(); /* Push any new pages onto the LRU now */
1660}
1661
1662/*
1663 * We hold the mm semaphore and the page_table_lock on entry and
1664 * should release the pagetable lock on exit..
1665 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001666static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1667 unsigned long address, pte_t *page_table, pmd_t *pmd,
1668 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001669{
1670 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001671 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001672 pte_t pte;
1673 int ret = VM_FAULT_MINOR;
1674
1675 pte_unmap(page_table);
1676 spin_unlock(&mm->page_table_lock);
Hugh Dickins65500d22005-10-29 18:15:59 -07001677
1678 entry = pte_to_swp_entry(orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 page = lookup_swap_cache(entry);
1680 if (!page) {
1681 swapin_readahead(entry, address, vma);
1682 page = read_swap_cache_async(entry, vma, address);
1683 if (!page) {
1684 /*
1685 * Back out if somebody else faulted in this pte while
1686 * we released the page table lock.
1687 */
1688 spin_lock(&mm->page_table_lock);
1689 page_table = pte_offset_map(pmd, address);
1690 if (likely(pte_same(*page_table, orig_pte)))
1691 ret = VM_FAULT_OOM;
Hugh Dickins65500d22005-10-29 18:15:59 -07001692 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001693 }
1694
1695 /* Had to read the page from swap area: Major fault */
1696 ret = VM_FAULT_MAJOR;
1697 inc_page_state(pgmajfault);
1698 grab_swap_token();
1699 }
1700
1701 mark_page_accessed(page);
1702 lock_page(page);
1703
1704 /*
1705 * Back out if somebody else faulted in this pte while we
1706 * released the page table lock.
1707 */
1708 spin_lock(&mm->page_table_lock);
1709 page_table = pte_offset_map(pmd, address);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07001710 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07001711 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001712
1713 if (unlikely(!PageUptodate(page))) {
1714 ret = VM_FAULT_SIGBUS;
1715 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716 }
1717
1718 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001719
Hugh Dickins42946212005-10-29 18:16:05 -07001720 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721 pte = mk_pte(page, vma->vm_page_prot);
1722 if (write_access && can_share_swap_page(page)) {
1723 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1724 write_access = 0;
1725 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726
1727 flush_icache_page(vma, page);
1728 set_pte_at(mm, address, page_table, pte);
1729 page_add_anon_rmap(page, vma, address);
1730
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001731 swap_free(entry);
1732 if (vm_swap_full())
1733 remove_exclusive_swap_page(page);
1734 unlock_page(page);
1735
Linus Torvalds1da177e2005-04-16 15:20:36 -07001736 if (write_access) {
1737 if (do_wp_page(mm, vma, address,
1738 page_table, pmd, pte) == VM_FAULT_OOM)
1739 ret = VM_FAULT_OOM;
1740 goto out;
1741 }
1742
1743 /* No need to invalidate - it was non-present before */
1744 update_mmu_cache(vma, address, pte);
1745 lazy_mmu_prot_update(pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07001746unlock:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001747 pte_unmap(page_table);
1748 spin_unlock(&mm->page_table_lock);
1749out:
1750 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001751out_nomap:
1752 pte_unmap(page_table);
1753 spin_unlock(&mm->page_table_lock);
1754 unlock_page(page);
1755 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001756 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001757}
1758
1759/*
1760 * We are called with the MM semaphore and page_table_lock
1761 * spinlock held to protect against concurrent faults in
1762 * multithreaded programs.
1763 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001764static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1765 unsigned long address, pte_t *page_table, pmd_t *pmd,
1766 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767{
Nick Pigginb5810032005-10-29 18:16:12 -07001768 struct page *page = ZERO_PAGE(addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001769 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001770
Hugh Dickins72866f62005-10-29 18:15:55 -07001771 /* Mapping of ZERO_PAGE - vm_page_prot is readonly */
Nick Pigginb5810032005-10-29 18:16:12 -07001772 entry = mk_pte(page, vma->vm_page_prot);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773
Linus Torvalds1da177e2005-04-16 15:20:36 -07001774 if (write_access) {
1775 /* Allocate our own private page. */
1776 pte_unmap(page_table);
1777 spin_unlock(&mm->page_table_lock);
1778
1779 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001780 goto oom;
1781 page = alloc_zeroed_user_highpage(vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001782 if (!page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001783 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784
1785 spin_lock(&mm->page_table_lock);
Hugh Dickins65500d22005-10-29 18:15:59 -07001786 page_table = pte_offset_map(pmd, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001787
1788 if (!pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001789 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001790 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 }
Hugh Dickins42946212005-10-29 18:16:05 -07001792 inc_mm_counter(mm, anon_rss);
Hugh Dickins65500d22005-10-29 18:15:59 -07001793 entry = mk_pte(page, vma->vm_page_prot);
1794 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 lru_cache_add_active(page);
1796 SetPageReferenced(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001797 page_add_anon_rmap(page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07001798 } else {
1799 inc_mm_counter(mm, file_rss);
1800 page_add_file_rmap(page);
1801 page_cache_get(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001802 }
1803
Hugh Dickins65500d22005-10-29 18:15:59 -07001804 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001805
1806 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07001807 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001808 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001809unlock:
1810 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001811 spin_unlock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001812 return VM_FAULT_MINOR;
Hugh Dickins65500d22005-10-29 18:15:59 -07001813oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 return VM_FAULT_OOM;
1815}
1816
1817/*
1818 * do_no_page() tries to create a new page mapping. It aggressively
1819 * tries to share with existing pages, but makes a separate copy if
1820 * the "write_access" parameter is true in order to avoid the next
1821 * page fault.
1822 *
1823 * As this is called only for pages that do not currently exist, we
1824 * do not need to flush old virtual caches or the TLB.
1825 *
1826 * This is called with the MM semaphore held and the page table
1827 * spinlock held. Exit with the spinlock released.
1828 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001829static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
1830 unsigned long address, pte_t *page_table, pmd_t *pmd,
1831 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832{
Hugh Dickins65500d22005-10-29 18:15:59 -07001833 struct page *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834 struct address_space *mapping = NULL;
1835 pte_t entry;
1836 unsigned int sequence = 0;
1837 int ret = VM_FAULT_MINOR;
1838 int anon = 0;
1839
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840 pte_unmap(page_table);
1841 spin_unlock(&mm->page_table_lock);
1842
1843 if (vma->vm_file) {
1844 mapping = vma->vm_file->f_mapping;
1845 sequence = mapping->truncate_count;
1846 smp_rmb(); /* serializes i_size against truncate_count */
1847 }
1848retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001849 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
1850 /*
1851 * No smp_rmb is needed here as long as there's a full
1852 * spin_lock/unlock sequence inside the ->nopage callback
1853 * (for the pagecache lookup) that acts as an implicit
1854 * smp_mb() and prevents the i_size read to happen
1855 * after the next truncate_count read.
1856 */
1857
1858 /* no page was available -- either SIGBUS or OOM */
1859 if (new_page == NOPAGE_SIGBUS)
1860 return VM_FAULT_SIGBUS;
1861 if (new_page == NOPAGE_OOM)
1862 return VM_FAULT_OOM;
1863
1864 /*
1865 * Should we do an early C-O-W break?
1866 */
1867 if (write_access && !(vma->vm_flags & VM_SHARED)) {
1868 struct page *page;
1869
1870 if (unlikely(anon_vma_prepare(vma)))
1871 goto oom;
1872 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1873 if (!page)
1874 goto oom;
1875 copy_user_highpage(page, new_page, address);
1876 page_cache_release(new_page);
1877 new_page = page;
1878 anon = 1;
1879 }
1880
1881 spin_lock(&mm->page_table_lock);
1882 /*
1883 * For a file-backed vma, someone could have truncated or otherwise
1884 * invalidated this page. If unmap_mapping_range got called,
1885 * retry getting the page.
1886 */
1887 if (mapping && unlikely(sequence != mapping->truncate_count)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 spin_unlock(&mm->page_table_lock);
1889 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001890 cond_resched();
1891 sequence = mapping->truncate_count;
1892 smp_rmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 goto retry;
1894 }
1895 page_table = pte_offset_map(pmd, address);
1896
1897 /*
1898 * This silly early PAGE_DIRTY setting removes a race
1899 * due to the bad i386 page protection. But it's valid
1900 * for other architectures too.
1901 *
1902 * Note that if write_access is true, we either now have
1903 * an exclusive copy of the page, or this is a shared mapping,
1904 * so we can make it writable and dirty to avoid having to
1905 * handle that later.
1906 */
1907 /* Only go through if we didn't race with anybody else... */
1908 if (pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909 flush_icache_page(vma, new_page);
1910 entry = mk_pte(new_page, vma->vm_page_prot);
1911 if (write_access)
1912 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1913 set_pte_at(mm, address, page_table, entry);
1914 if (anon) {
Hugh Dickins42946212005-10-29 18:16:05 -07001915 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001916 lru_cache_add_active(new_page);
1917 page_add_anon_rmap(new_page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07001918 } else if (!(vma->vm_flags & VM_RESERVED)) {
Hugh Dickins42946212005-10-29 18:16:05 -07001919 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 page_add_file_rmap(new_page);
Hugh Dickins42946212005-10-29 18:16:05 -07001921 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922 } else {
1923 /* One of our sibling threads was faster, back out. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001925 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 }
1927
1928 /* no need to invalidate: a not-present page shouldn't be cached */
1929 update_mmu_cache(vma, address, entry);
1930 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001931unlock:
1932 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933 spin_unlock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934 return ret;
1935oom:
1936 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001937 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001938}
1939
1940/*
1941 * Fault of a previously existing named mapping. Repopulate the pte
1942 * from the encoded file_pte if possible. This enables swappable
1943 * nonlinear vmas.
1944 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001945static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
1946 unsigned long address, pte_t *page_table, pmd_t *pmd,
1947 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948{
Hugh Dickins65500d22005-10-29 18:15:59 -07001949 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 int err;
1951
Hugh Dickins65500d22005-10-29 18:15:59 -07001952 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 spin_unlock(&mm->page_table_lock);
1954
Hugh Dickins65500d22005-10-29 18:15:59 -07001955 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
1956 /*
1957 * Page table corrupted: show pte and kill process.
1958 */
Nick Pigginb5810032005-10-29 18:16:12 -07001959 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07001960 return VM_FAULT_OOM;
1961 }
1962 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
1963
1964 pgoff = pte_to_pgoff(orig_pte);
1965 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
1966 vma->vm_page_prot, pgoff, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 if (err == -ENOMEM)
1968 return VM_FAULT_OOM;
1969 if (err)
1970 return VM_FAULT_SIGBUS;
1971 return VM_FAULT_MAJOR;
1972}
1973
1974/*
1975 * These routines also need to handle stuff like marking pages dirty
1976 * and/or accessed for architectures that don't do it in hardware (most
1977 * RISC architectures). The early dirtying is also good on the i386.
1978 *
1979 * There is also a hook called "update_mmu_cache()" that architectures
1980 * with external mmu caches can use to update those (ie the Sparc or
1981 * PowerPC hashed page tables that act as extended TLBs).
1982 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07001983 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1984 * but allow concurrent faults), and pte mapped but not yet locked.
1985 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 */
1987static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07001988 struct vm_area_struct *vma, unsigned long address,
1989 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990{
1991 pte_t entry;
1992
Hugh Dickinsc74df322005-10-29 18:16:23 -07001993 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 entry = *pte;
1995 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07001996 if (pte_none(entry)) {
1997 if (!vma->vm_ops || !vma->vm_ops->nopage)
1998 return do_anonymous_page(mm, vma, address,
1999 pte, pmd, write_access);
2000 return do_no_page(mm, vma, address,
2001 pte, pmd, write_access);
2002 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003 if (pte_file(entry))
Hugh Dickins65500d22005-10-29 18:15:59 -07002004 return do_file_page(mm, vma, address,
2005 pte, pmd, write_access, entry);
2006 return do_swap_page(mm, vma, address,
2007 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 }
2009
2010 if (write_access) {
2011 if (!pte_write(entry))
2012 return do_wp_page(mm, vma, address, pte, pmd, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 entry = pte_mkdirty(entry);
2014 }
2015 entry = pte_mkyoung(entry);
2016 ptep_set_access_flags(vma, address, pte, entry, write_access);
2017 update_mmu_cache(vma, address, entry);
2018 lazy_mmu_prot_update(entry);
2019 pte_unmap(pte);
2020 spin_unlock(&mm->page_table_lock);
2021 return VM_FAULT_MINOR;
2022}
2023
2024/*
2025 * By the time we get here, we already hold the mm semaphore
2026 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002027int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028 unsigned long address, int write_access)
2029{
2030 pgd_t *pgd;
2031 pud_t *pud;
2032 pmd_t *pmd;
2033 pte_t *pte;
2034
2035 __set_current_state(TASK_RUNNING);
2036
2037 inc_page_state(pgfault);
2038
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002039 if (unlikely(is_vm_hugetlb_page(vma)))
2040 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043 pud = pud_alloc(mm, pgd, address);
2044 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002045 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 pmd = pmd_alloc(mm, pud, address);
2047 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002048 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 pte = pte_alloc_map(mm, pmd, address);
2050 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002051 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052
Hugh Dickinsc74df322005-10-29 18:16:23 -07002053 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002054}
2055
2056#ifndef __PAGETABLE_PUD_FOLDED
2057/*
2058 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002059 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002060 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002061int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002063 pud_t *new = pud_alloc_one(mm, address);
2064 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002065 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066
Hugh Dickins872fec12005-10-29 18:16:21 -07002067 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002068 if (pgd_present(*pgd)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002069 pud_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002070 else
2071 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002072 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002073 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074}
2075#endif /* __PAGETABLE_PUD_FOLDED */
2076
2077#ifndef __PAGETABLE_PMD_FOLDED
2078/*
2079 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002080 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002082int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002083{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002084 pmd_t *new = pmd_alloc_one(mm, address);
2085 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002086 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002087
Hugh Dickins872fec12005-10-29 18:16:21 -07002088 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002090 if (pud_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002091 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002092 else
2093 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002094#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002095 if (pgd_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002097 else
2098 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002100 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002101 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102}
2103#endif /* __PAGETABLE_PMD_FOLDED */
2104
2105int make_pages_present(unsigned long addr, unsigned long end)
2106{
2107 int ret, len, write;
2108 struct vm_area_struct * vma;
2109
2110 vma = find_vma(current->mm, addr);
2111 if (!vma)
2112 return -1;
2113 write = (vma->vm_flags & VM_WRITE) != 0;
2114 if (addr >= end)
2115 BUG();
2116 if (end > vma->vm_end)
2117 BUG();
2118 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2119 ret = get_user_pages(current, current->mm, addr,
2120 len, write, 0, NULL, NULL);
2121 if (ret < 0)
2122 return ret;
2123 return ret == len ? 0 : -1;
2124}
2125
2126/*
2127 * Map a vmalloc()-space virtual address to the physical page.
2128 */
2129struct page * vmalloc_to_page(void * vmalloc_addr)
2130{
2131 unsigned long addr = (unsigned long) vmalloc_addr;
2132 struct page *page = NULL;
2133 pgd_t *pgd = pgd_offset_k(addr);
2134 pud_t *pud;
2135 pmd_t *pmd;
2136 pte_t *ptep, pte;
2137
2138 if (!pgd_none(*pgd)) {
2139 pud = pud_offset(pgd, addr);
2140 if (!pud_none(*pud)) {
2141 pmd = pmd_offset(pud, addr);
2142 if (!pmd_none(*pmd)) {
2143 ptep = pte_offset_map(pmd, addr);
2144 pte = *ptep;
2145 if (pte_present(pte))
2146 page = pte_page(pte);
2147 pte_unmap(ptep);
2148 }
2149 }
2150 }
2151 return page;
2152}
2153
2154EXPORT_SYMBOL(vmalloc_to_page);
2155
2156/*
2157 * Map a vmalloc()-space virtual address to the physical page frame number.
2158 */
2159unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2160{
2161 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2162}
2163
2164EXPORT_SYMBOL(vmalloc_to_pfn);
2165
Linus Torvalds1da177e2005-04-16 15:20:36 -07002166#if !defined(__HAVE_ARCH_GATE_AREA)
2167
2168#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002169static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002170
2171static int __init gate_vma_init(void)
2172{
2173 gate_vma.vm_mm = NULL;
2174 gate_vma.vm_start = FIXADDR_USER_START;
2175 gate_vma.vm_end = FIXADDR_USER_END;
2176 gate_vma.vm_page_prot = PAGE_READONLY;
Nick Pigginb5810032005-10-29 18:16:12 -07002177 gate_vma.vm_flags = VM_RESERVED;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002178 return 0;
2179}
2180__initcall(gate_vma_init);
2181#endif
2182
2183struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2184{
2185#ifdef AT_SYSINFO_EHDR
2186 return &gate_vma;
2187#else
2188 return NULL;
2189#endif
2190}
2191
2192int in_gate_area_no_task(unsigned long addr)
2193{
2194#ifdef AT_SYSINFO_EHDR
2195 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2196 return 1;
2197#endif
2198 return 0;
2199}
2200
2201#endif /* __HAVE_ARCH_GATE_AREA */