blob: 247b5c312b9b073d1c76769a67e73d39ee8bdd39 [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
Andi Kleena62eaf12006-02-16 23:41:58 +010085int randomize_va_space __read_mostly = 1;
86
87static int __init disable_randmaps(char *s)
88{
89 randomize_va_space = 0;
OGAWA Hirofumi9b410462006-03-31 02:30:33 -080090 return 1;
Andi Kleena62eaf12006-02-16 23:41:58 +010091}
92__setup("norandmaps", disable_randmaps);
93
94
Linus Torvalds1da177e2005-04-16 15:20:36 -070095/*
96 * If a p?d_bad entry is found while walking page tables, report
97 * the error, before resetting entry to p?d_none. Usually (but
98 * very seldom) called out from the p?d_none_or_clear_bad macros.
99 */
100
101void pgd_clear_bad(pgd_t *pgd)
102{
103 pgd_ERROR(*pgd);
104 pgd_clear(pgd);
105}
106
107void pud_clear_bad(pud_t *pud)
108{
109 pud_ERROR(*pud);
110 pud_clear(pud);
111}
112
113void pmd_clear_bad(pmd_t *pmd)
114{
115 pmd_ERROR(*pmd);
116 pmd_clear(pmd);
117}
118
119/*
120 * Note: this doesn't free the actual pages themselves. That
121 * has been handled earlier when unmapping all the memory regions.
122 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700123static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124{
Hugh Dickinse0da3822005-04-19 13:29:15 -0700125 struct page *page = pmd_page(*pmd);
126 pmd_clear(pmd);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700127 pte_lock_deinit(page);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700128 pte_free_tlb(tlb, page);
129 dec_page_state(nr_page_table_pages);
130 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131}
132
Hugh Dickinse0da3822005-04-19 13:29:15 -0700133static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
134 unsigned long addr, unsigned long end,
135 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136{
137 pmd_t *pmd;
138 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700139 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140
Hugh Dickinse0da3822005-04-19 13:29:15 -0700141 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 do {
144 next = pmd_addr_end(addr, end);
145 if (pmd_none_or_clear_bad(pmd))
146 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700147 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 } while (pmd++, addr = next, addr != end);
149
Hugh Dickinse0da3822005-04-19 13:29:15 -0700150 start &= PUD_MASK;
151 if (start < floor)
152 return;
153 if (ceiling) {
154 ceiling &= PUD_MASK;
155 if (!ceiling)
156 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700157 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700158 if (end - 1 > ceiling - 1)
159 return;
160
161 pmd = pmd_offset(pud, start);
162 pud_clear(pud);
163 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164}
165
Hugh Dickinse0da3822005-04-19 13:29:15 -0700166static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
167 unsigned long addr, unsigned long end,
168 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169{
170 pud_t *pud;
171 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700172 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700173
Hugh Dickinse0da3822005-04-19 13:29:15 -0700174 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 do {
177 next = pud_addr_end(addr, end);
178 if (pud_none_or_clear_bad(pud))
179 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700180 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181 } while (pud++, addr = next, addr != end);
182
Hugh Dickinse0da3822005-04-19 13:29:15 -0700183 start &= PGDIR_MASK;
184 if (start < floor)
185 return;
186 if (ceiling) {
187 ceiling &= PGDIR_MASK;
188 if (!ceiling)
189 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700190 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700191 if (end - 1 > ceiling - 1)
192 return;
193
194 pud = pud_offset(pgd, start);
195 pgd_clear(pgd);
196 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197}
198
199/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700200 * This function frees user-level page tables of a process.
201 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 * Must be called with pagetable lock held.
203 */
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700204void free_pgd_range(struct mmu_gather **tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700205 unsigned long addr, unsigned long end,
206 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207{
208 pgd_t *pgd;
209 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700210 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700211
Hugh Dickinse0da3822005-04-19 13:29:15 -0700212 /*
213 * The next few lines have given us lots of grief...
214 *
215 * Why are we testing PMD* at this top level? Because often
216 * there will be no work to do at all, and we'd prefer not to
217 * go all the way down to the bottom just to discover that.
218 *
219 * Why all these "- 1"s? Because 0 represents both the bottom
220 * of the address space and the top of it (using -1 for the
221 * top wouldn't help much: the masks would do the wrong thing).
222 * The rule is that addr 0 and floor 0 refer to the bottom of
223 * the address space, but end 0 and ceiling 0 refer to the top
224 * Comparisons need to use "end - 1" and "ceiling - 1" (though
225 * that end 0 case should be mythical).
226 *
227 * Wherever addr is brought up or ceiling brought down, we must
228 * be careful to reject "the opposite 0" before it confuses the
229 * subsequent tests. But what about where end is brought down
230 * by PMD_SIZE below? no, end can't go down to 0 there.
231 *
232 * Whereas we round start (addr) and ceiling down, by different
233 * masks at different levels, in order to test whether a table
234 * now has no other vmas using it, so can be freed, we don't
235 * bother to round floor or end up - the tests don't need that.
236 */
237
238 addr &= PMD_MASK;
239 if (addr < floor) {
240 addr += PMD_SIZE;
241 if (!addr)
242 return;
243 }
244 if (ceiling) {
245 ceiling &= PMD_MASK;
246 if (!ceiling)
247 return;
248 }
249 if (end - 1 > ceiling - 1)
250 end -= PMD_SIZE;
251 if (addr > end - 1)
252 return;
253
254 start = addr;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700255 pgd = pgd_offset((*tlb)->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 do {
257 next = pgd_addr_end(addr, end);
258 if (pgd_none_or_clear_bad(pgd))
259 continue;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700260 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700262
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700263 if (!(*tlb)->fullmm)
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700264 flush_tlb_pgtables((*tlb)->mm, start, end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700265}
266
267void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700268 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700269{
270 while (vma) {
271 struct vm_area_struct *next = vma->vm_next;
272 unsigned long addr = vma->vm_start;
273
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700274 /*
275 * Hide vma from rmap and vmtruncate before freeing pgtables
276 */
277 anon_vma_unlink(vma);
278 unlink_file_vma(vma);
279
David Gibson9da61ae2006-03-22 00:08:57 -0800280 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700281 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700282 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700283 } else {
284 /*
285 * Optimization: gather nearby vmas into one call down
286 */
287 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800288 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700289 vma = next;
290 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700291 anon_vma_unlink(vma);
292 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700293 }
294 free_pgd_range(tlb, addr, vma->vm_end,
295 floor, next? next->vm_start: ceiling);
296 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700297 vma = next;
298 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299}
300
Hugh Dickins1bb36302005-10-29 18:16:22 -0700301int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700302{
Hugh Dickinsc74df322005-10-29 18:16:23 -0700303 struct page *new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700304 if (!new)
305 return -ENOMEM;
306
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700307 pte_lock_init(new);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700308 spin_lock(&mm->page_table_lock);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700309 if (pmd_present(*pmd)) { /* Another has populated it */
310 pte_lock_deinit(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700311 pte_free(new);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700312 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 mm->nr_ptes++;
314 inc_page_state(nr_page_table_pages);
315 pmd_populate(mm, pmd, new);
316 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700317 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700318 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700319}
320
Hugh Dickins1bb36302005-10-29 18:16:22 -0700321int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700323 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
324 if (!new)
325 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326
Hugh Dickins1bb36302005-10-29 18:16:22 -0700327 spin_lock(&init_mm.page_table_lock);
328 if (pmd_present(*pmd)) /* Another has populated it */
329 pte_free_kernel(new);
330 else
331 pmd_populate_kernel(&init_mm, pmd, new);
332 spin_unlock(&init_mm.page_table_lock);
333 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334}
335
Hugh Dickinsae859762005-10-29 18:16:05 -0700336static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
337{
338 if (file_rss)
339 add_mm_counter(mm, file_rss, file_rss);
340 if (anon_rss)
341 add_mm_counter(mm, anon_rss, anon_rss);
342}
343
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800345 * This function is called to print an error when a bad pte
346 * is found. For example, we might have a PFN-mapped pte in
347 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700348 *
349 * The calling function must still handle the error.
350 */
351void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
352{
353 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
354 "vm_flags = %lx, vaddr = %lx\n",
355 (long long)pte_val(pte),
356 (vma->vm_mm == current->mm ? current->comm : "???"),
357 vma->vm_flags, vaddr);
358 dump_stack();
359}
360
Linus Torvalds67121172005-12-11 20:38:17 -0800361static inline int is_cow_mapping(unsigned int flags)
362{
363 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
364}
365
Nick Pigginb5810032005-10-29 18:16:12 -0700366/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800367 * This function gets the "struct page" associated with a pte.
368 *
369 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
370 * will have each page table entry just pointing to a raw page frame
371 * number, and as far as the VM layer is concerned, those do not have
372 * pages associated with them - even if the PFN might point to memory
373 * that otherwise is perfectly fine and has a "struct page".
374 *
375 * The way we recognize those mappings is through the rules set up
376 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
377 * and the vm_pgoff will point to the first PFN mapped: thus every
378 * page that is a raw mapping will always honor the rule
379 *
380 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
381 *
382 * and if that isn't true, the page has been COW'ed (in which case it
383 * _does_ have a "struct page" associated with it even if it is in a
384 * VM_PFNMAP range).
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800385 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800386struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800387{
Linus Torvalds6aab3412005-11-28 14:34:23 -0800388 unsigned long pfn = pte_pfn(pte);
389
Nick Pigginb7ab7952006-03-22 00:08:42 -0800390 if (unlikely(vma->vm_flags & VM_PFNMAP)) {
Linus Torvalds6aab3412005-11-28 14:34:23 -0800391 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
392 if (pfn == vma->vm_pgoff + off)
393 return NULL;
Linus Torvalds67121172005-12-11 20:38:17 -0800394 if (!is_cow_mapping(vma->vm_flags))
Linus Torvaldsfb155c12005-12-11 19:46:02 -0800395 return NULL;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800396 }
397
Nick Piggin315ab192006-03-25 16:20:22 +0100398 /*
399 * Add some anal sanity checks for now. Eventually,
400 * we should just do "return pfn_to_page(pfn)", but
401 * in the meantime we check that we get a valid pfn,
402 * and that the resulting page looks ok.
403 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800404 if (unlikely(!pfn_valid(pfn))) {
405 print_bad_pte(vma, pte, addr);
406 return NULL;
407 }
408
409 /*
410 * NOTE! We still have PageReserved() pages in the page
411 * tables.
412 *
413 * The PAGE_ZERO() pages and various VDSO mappings can
414 * cause them to exist.
415 */
416 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800417}
418
419/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 * copy one vm_area from one task to the other. Assumes the page tables
421 * already present in the new task to be cleared in the whole range
422 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 */
424
Hugh Dickins8c103762005-10-29 18:16:13 -0700425static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700427 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700428 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429{
Nick Pigginb5810032005-10-29 18:16:12 -0700430 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 pte_t pte = *src_pte;
432 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433
434 /* pte contains position in swap or file, so copy. */
435 if (unlikely(!pte_present(pte))) {
436 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700437 swp_entry_t entry = pte_to_swp_entry(pte);
438
439 swap_duplicate(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 /* make sure dst_mm is on swapoff's mmlist. */
441 if (unlikely(list_empty(&dst_mm->mmlist))) {
442 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700443 if (list_empty(&dst_mm->mmlist))
444 list_add(&dst_mm->mmlist,
445 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 spin_unlock(&mmlist_lock);
447 }
Christoph Lameter06972122006-06-23 02:03:35 -0700448 if (is_write_migration_entry(entry) &&
449 is_cow_mapping(vm_flags)) {
450 /*
451 * COW mappings require pages in both parent
452 * and child to be set to read.
453 */
454 make_migration_entry_read(&entry);
455 pte = swp_entry_to_pte(entry);
456 set_pte_at(src_mm, addr, src_pte, pte);
457 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700459 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 }
461
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 /*
463 * If it's a COW mapping, write protect it both
464 * in the parent and the child
465 */
Linus Torvalds67121172005-12-11 20:38:17 -0800466 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 ptep_set_wrprotect(src_mm, addr, src_pte);
468 pte = *src_pte;
469 }
470
471 /*
472 * If it's a shared mapping, mark it clean in
473 * the child
474 */
475 if (vm_flags & VM_SHARED)
476 pte = pte_mkclean(pte);
477 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800478
479 page = vm_normal_page(vma, addr, pte);
480 if (page) {
481 get_page(page);
482 page_dup_rmap(page);
483 rss[!!PageAnon(page)]++;
484 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700485
486out_set_pte:
487 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488}
489
490static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
491 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
492 unsigned long addr, unsigned long end)
493{
494 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700495 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700496 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700497 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
499again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700500 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700501 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 if (!dst_pte)
503 return -ENOMEM;
504 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700505 src_ptl = pte_lockptr(src_mm, src_pmd);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700506 spin_lock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 do {
509 /*
510 * We are holding two locks at this point - either of them
511 * could generate latencies in another task on another CPU.
512 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700513 if (progress >= 32) {
514 progress = 0;
515 if (need_resched() ||
Hugh Dickinsc74df322005-10-29 18:16:23 -0700516 need_lockbreak(src_ptl) ||
517 need_lockbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700518 break;
519 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 if (pte_none(*src_pte)) {
521 progress++;
522 continue;
523 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700524 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700525 progress += 8;
526 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
Hugh Dickinsc74df322005-10-29 18:16:23 -0700528 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700530 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700531 pte_unmap_unlock(dst_pte - 1, dst_ptl);
532 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 if (addr != end)
534 goto again;
535 return 0;
536}
537
538static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
539 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
540 unsigned long addr, unsigned long end)
541{
542 pmd_t *src_pmd, *dst_pmd;
543 unsigned long next;
544
545 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
546 if (!dst_pmd)
547 return -ENOMEM;
548 src_pmd = pmd_offset(src_pud, addr);
549 do {
550 next = pmd_addr_end(addr, end);
551 if (pmd_none_or_clear_bad(src_pmd))
552 continue;
553 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
554 vma, addr, next))
555 return -ENOMEM;
556 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
557 return 0;
558}
559
560static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
561 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
562 unsigned long addr, unsigned long end)
563{
564 pud_t *src_pud, *dst_pud;
565 unsigned long next;
566
567 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
568 if (!dst_pud)
569 return -ENOMEM;
570 src_pud = pud_offset(src_pgd, addr);
571 do {
572 next = pud_addr_end(addr, end);
573 if (pud_none_or_clear_bad(src_pud))
574 continue;
575 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
576 vma, addr, next))
577 return -ENOMEM;
578 } while (dst_pud++, src_pud++, addr = next, addr != end);
579 return 0;
580}
581
582int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
583 struct vm_area_struct *vma)
584{
585 pgd_t *src_pgd, *dst_pgd;
586 unsigned long next;
587 unsigned long addr = vma->vm_start;
588 unsigned long end = vma->vm_end;
589
Nick Piggind9928952005-08-28 16:49:11 +1000590 /*
591 * Don't copy ptes where a page fault will fill them correctly.
592 * Fork becomes much lighter when there are big shared or private
593 * readonly mappings. The tradeoff is that copy_page_range is more
594 * efficient than faulting.
595 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800596 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000597 if (!vma->anon_vma)
598 return 0;
599 }
600
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 if (is_vm_hugetlb_page(vma))
602 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
603
604 dst_pgd = pgd_offset(dst_mm, addr);
605 src_pgd = pgd_offset(src_mm, addr);
606 do {
607 next = pgd_addr_end(addr, end);
608 if (pgd_none_or_clear_bad(src_pgd))
609 continue;
610 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
611 vma, addr, next))
612 return -ENOMEM;
613 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
614 return 0;
615}
616
Robin Holt51c6f662005-11-13 16:06:42 -0800617static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700618 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800620 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621{
Nick Pigginb5810032005-10-29 18:16:12 -0700622 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700624 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700625 int file_rss = 0;
626 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627
Hugh Dickins508034a2005-10-29 18:16:30 -0700628 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 do {
630 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800631 if (pte_none(ptent)) {
632 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800634 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800635
636 (*zap_work) -= PAGE_SIZE;
637
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800639 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800640
Linus Torvalds6aab3412005-11-28 14:34:23 -0800641 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 if (unlikely(details) && page) {
643 /*
644 * unmap_shared_mapping_pages() wants to
645 * invalidate cache without truncating:
646 * unmap shared but keep private pages.
647 */
648 if (details->check_mapping &&
649 details->check_mapping != page->mapping)
650 continue;
651 /*
652 * Each page->index must be checked when
653 * invalidating or truncating nonlinear.
654 */
655 if (details->nonlinear_vma &&
656 (page->index < details->first_index ||
657 page->index > details->last_index))
658 continue;
659 }
Nick Pigginb5810032005-10-29 18:16:12 -0700660 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700661 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 tlb_remove_tlb_entry(tlb, pte, addr);
663 if (unlikely(!page))
664 continue;
665 if (unlikely(details) && details->nonlinear_vma
666 && linear_page_index(details->nonlinear_vma,
667 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700668 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700671 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700672 else {
673 if (pte_dirty(ptent))
674 set_page_dirty(page);
675 if (pte_young(ptent))
676 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700677 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700678 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679 page_remove_rmap(page);
680 tlb_remove_page(tlb, page);
681 continue;
682 }
683 /*
684 * If details->check_mapping, we leave swap entries;
685 * if details->nonlinear_vma, we leave file entries.
686 */
687 if (unlikely(details))
688 continue;
689 if (!pte_file(ptent))
690 free_swap_and_cache(pte_to_swp_entry(ptent));
Nick Pigginb5810032005-10-29 18:16:12 -0700691 pte_clear_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800692 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700693
Hugh Dickins86d912f2005-10-29 18:16:14 -0700694 add_mm_rss(mm, file_rss, anon_rss);
Hugh Dickins508034a2005-10-29 18:16:30 -0700695 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800696
697 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698}
699
Robin Holt51c6f662005-11-13 16:06:42 -0800700static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700701 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800703 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704{
705 pmd_t *pmd;
706 unsigned long next;
707
708 pmd = pmd_offset(pud, addr);
709 do {
710 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800711 if (pmd_none_or_clear_bad(pmd)) {
712 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800714 }
715 next = zap_pte_range(tlb, vma, pmd, addr, next,
716 zap_work, details);
717 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
718
719 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720}
721
Robin Holt51c6f662005-11-13 16:06:42 -0800722static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700723 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800725 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726{
727 pud_t *pud;
728 unsigned long next;
729
730 pud = pud_offset(pgd, addr);
731 do {
732 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800733 if (pud_none_or_clear_bad(pud)) {
734 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800736 }
737 next = zap_pmd_range(tlb, vma, pud, addr, next,
738 zap_work, details);
739 } while (pud++, addr = next, (addr != end && *zap_work > 0));
740
741 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742}
743
Robin Holt51c6f662005-11-13 16:06:42 -0800744static unsigned long unmap_page_range(struct mmu_gather *tlb,
745 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800747 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748{
749 pgd_t *pgd;
750 unsigned long next;
751
752 if (details && !details->check_mapping && !details->nonlinear_vma)
753 details = NULL;
754
755 BUG_ON(addr >= end);
756 tlb_start_vma(tlb, vma);
757 pgd = pgd_offset(vma->vm_mm, addr);
758 do {
759 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800760 if (pgd_none_or_clear_bad(pgd)) {
761 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800763 }
764 next = zap_pud_range(tlb, vma, pgd, addr, next,
765 zap_work, details);
766 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700767 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800768
769 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770}
771
772#ifdef CONFIG_PREEMPT
773# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
774#else
775/* No preempt: go for improved straight-line efficiency */
776# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
777#endif
778
779/**
780 * unmap_vmas - unmap a range of memory covered by a list of vma's
781 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 * @vma: the starting vma
783 * @start_addr: virtual address at which to start unmapping
784 * @end_addr: virtual address at which to end unmapping
785 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
786 * @details: details of nonlinear truncation or shared cache invalidation
787 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700788 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700790 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700792 * We aim to not hold locks for too long (for scheduling latency reasons).
793 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 * return the ending mmu_gather to the caller.
795 *
796 * Only addresses between `start' and `end' will be unmapped.
797 *
798 * The VMA list must be sorted in ascending virtual address order.
799 *
800 * unmap_vmas() assumes that the caller will flush the whole unmapped address
801 * range after unmap_vmas() returns. So the only responsibility here is to
802 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
803 * drops the lock and schedules.
804 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700805unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 struct vm_area_struct *vma, unsigned long start_addr,
807 unsigned long end_addr, unsigned long *nr_accounted,
808 struct zap_details *details)
809{
Robin Holt51c6f662005-11-13 16:06:42 -0800810 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
812 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700813 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700814 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700815 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700816
817 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 unsigned long end;
819
820 start = max(vma->vm_start, start_addr);
821 if (start >= vma->vm_end)
822 continue;
823 end = min(vma->vm_end, end_addr);
824 if (end <= vma->vm_start)
825 continue;
826
827 if (vma->vm_flags & VM_ACCOUNT)
828 *nr_accounted += (end - start) >> PAGE_SHIFT;
829
Linus Torvalds1da177e2005-04-16 15:20:36 -0700830 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 if (!tlb_start_valid) {
832 tlb_start = start;
833 tlb_start_valid = 1;
834 }
835
Robin Holt51c6f662005-11-13 16:06:42 -0800836 if (unlikely(is_vm_hugetlb_page(vma))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 unmap_hugepage_range(vma, start, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800838 zap_work -= (end - start) /
839 (HPAGE_SIZE / PAGE_SIZE);
840 start = end;
841 } else
842 start = unmap_page_range(*tlbp, vma,
843 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844
Robin Holt51c6f662005-11-13 16:06:42 -0800845 if (zap_work > 0) {
846 BUG_ON(start != end);
847 break;
848 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849
850 tlb_finish_mmu(*tlbp, tlb_start, start);
851
852 if (need_resched() ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
854 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700855 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 goto out;
857 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 }
860
Hugh Dickins508034a2005-10-29 18:16:30 -0700861 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700862 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800863 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 }
865 }
866out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700867 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868}
869
870/**
871 * zap_page_range - remove user pages in a given range
872 * @vma: vm_area_struct holding the applicable pages
873 * @address: starting address of pages to zap
874 * @size: number of bytes to zap
875 * @details: details of nonlinear truncation or shared cache invalidation
876 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700877unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 unsigned long size, struct zap_details *details)
879{
880 struct mm_struct *mm = vma->vm_mm;
881 struct mmu_gather *tlb;
882 unsigned long end = address + size;
883 unsigned long nr_accounted = 0;
884
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700887 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700888 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
889 if (tlb)
890 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700891 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892}
893
894/*
895 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800897struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700898 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700899{
900 pgd_t *pgd;
901 pud_t *pud;
902 pmd_t *pmd;
903 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700904 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800906 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700908 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
909 if (!IS_ERR(page)) {
910 BUG_ON(flags & FOLL_GET);
911 goto out;
912 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700914 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 pgd = pgd_offset(mm, address);
916 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700917 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918
919 pud = pud_offset(pgd, address);
920 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700921 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922
923 pmd = pmd_offset(pud, address);
924 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700925 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700927 if (pmd_huge(*pmd)) {
928 BUG_ON(flags & FOLL_GET);
929 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
930 goto out;
931 }
932
933 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 if (!ptep)
935 goto out;
936
937 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700938 if (!pte_present(pte))
939 goto unlock;
940 if ((flags & FOLL_WRITE) && !pte_write(pte))
941 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800942 page = vm_normal_page(vma, address, pte);
943 if (unlikely(!page))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700944 goto unlock;
945
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700946 if (flags & FOLL_GET)
947 get_page(page);
948 if (flags & FOLL_TOUCH) {
949 if ((flags & FOLL_WRITE) &&
950 !pte_dirty(pte) && !PageDirty(page))
951 set_page_dirty(page);
952 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700954unlock:
955 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700957 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700959no_page_table:
960 /*
961 * When core dumping an enormous anonymous area that nobody
962 * has touched so far, we don't want to allocate page tables.
963 */
964 if (flags & FOLL_ANON) {
965 page = ZERO_PAGE(address);
966 if (flags & FOLL_GET)
967 get_page(page);
968 BUG_ON(flags & FOLL_WRITE);
969 }
970 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971}
972
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
974 unsigned long start, int len, int write, int force,
975 struct page **pages, struct vm_area_struct **vmas)
976{
977 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700978 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
980 /*
981 * Require read or write permissions.
982 * If 'force' is set, we only require the "MAY" flags.
983 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700984 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
985 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 i = 0;
987
988 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700989 struct vm_area_struct *vma;
990 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991
992 vma = find_extend_vma(mm, start);
993 if (!vma && in_gate_area(tsk, start)) {
994 unsigned long pg = start & PAGE_MASK;
995 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
996 pgd_t *pgd;
997 pud_t *pud;
998 pmd_t *pmd;
999 pte_t *pte;
1000 if (write) /* user gate pages are read-only */
1001 return i ? : -EFAULT;
1002 if (pg > TASK_SIZE)
1003 pgd = pgd_offset_k(pg);
1004 else
1005 pgd = pgd_offset_gate(mm, pg);
1006 BUG_ON(pgd_none(*pgd));
1007 pud = pud_offset(pgd, pg);
1008 BUG_ON(pud_none(*pud));
1009 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001010 if (pmd_none(*pmd))
1011 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001013 if (pte_none(*pte)) {
1014 pte_unmap(pte);
1015 return i ? : -EFAULT;
1016 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001018 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001019 pages[i] = page;
1020 if (page)
1021 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 }
1023 pte_unmap(pte);
1024 if (vmas)
1025 vmas[i] = gate_vma;
1026 i++;
1027 start += PAGE_SIZE;
1028 len--;
1029 continue;
1030 }
1031
Linus Torvalds1ff80382005-12-12 16:24:33 -08001032 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001033 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001034 return i ? : -EFAULT;
1035
1036 if (is_vm_hugetlb_page(vma)) {
1037 i = follow_hugetlb_page(mm, vma, pages, vmas,
1038 &start, &len, i);
1039 continue;
1040 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001041
1042 foll_flags = FOLL_TOUCH;
1043 if (pages)
1044 foll_flags |= FOLL_GET;
1045 if (!write && !(vma->vm_flags & VM_LOCKED) &&
1046 (!vma->vm_ops || !vma->vm_ops->nopage))
1047 foll_flags |= FOLL_ANON;
1048
Linus Torvalds1da177e2005-04-16 15:20:36 -07001049 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001050 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001051
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001052 if (write)
1053 foll_flags |= FOLL_WRITE;
1054
1055 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001056 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001057 int ret;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001058 ret = __handle_mm_fault(mm, vma, start,
1059 foll_flags & FOLL_WRITE);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001060 /*
1061 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1062 * broken COW when necessary, even if maybe_mkwrite
1063 * decided not to set pte_write. We can thus safely do
1064 * subsequent page lookups as if they were reads.
1065 */
1066 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001067 foll_flags &= ~FOLL_WRITE;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001068
1069 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001070 case VM_FAULT_MINOR:
1071 tsk->min_flt++;
1072 break;
1073 case VM_FAULT_MAJOR:
1074 tsk->maj_flt++;
1075 break;
1076 case VM_FAULT_SIGBUS:
1077 return i ? i : -EFAULT;
1078 case VM_FAULT_OOM:
1079 return i ? i : -ENOMEM;
1080 default:
1081 BUG();
1082 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 }
1084 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001085 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001086
1087 flush_anon_page(page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001088 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001089 }
1090 if (vmas)
1091 vmas[i] = vma;
1092 i++;
1093 start += PAGE_SIZE;
1094 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001095 } while (len && start < vma->vm_end);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001096 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001097 return i;
1098}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001099EXPORT_SYMBOL(get_user_pages);
1100
1101static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1102 unsigned long addr, unsigned long end, pgprot_t prot)
1103{
1104 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001105 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106
Hugh Dickinsc74df322005-10-29 18:16:23 -07001107 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 if (!pte)
1109 return -ENOMEM;
1110 do {
Nick Pigginb5810032005-10-29 18:16:12 -07001111 struct page *page = ZERO_PAGE(addr);
1112 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1113 page_cache_get(page);
1114 page_add_file_rmap(page);
1115 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116 BUG_ON(!pte_none(*pte));
1117 set_pte_at(mm, addr, pte, zero_pte);
1118 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001119 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001120 return 0;
1121}
1122
1123static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1124 unsigned long addr, unsigned long end, pgprot_t prot)
1125{
1126 pmd_t *pmd;
1127 unsigned long next;
1128
1129 pmd = pmd_alloc(mm, pud, addr);
1130 if (!pmd)
1131 return -ENOMEM;
1132 do {
1133 next = pmd_addr_end(addr, end);
1134 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1135 return -ENOMEM;
1136 } while (pmd++, addr = next, addr != end);
1137 return 0;
1138}
1139
1140static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1141 unsigned long addr, unsigned long end, pgprot_t prot)
1142{
1143 pud_t *pud;
1144 unsigned long next;
1145
1146 pud = pud_alloc(mm, pgd, addr);
1147 if (!pud)
1148 return -ENOMEM;
1149 do {
1150 next = pud_addr_end(addr, end);
1151 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1152 return -ENOMEM;
1153 } while (pud++, addr = next, addr != end);
1154 return 0;
1155}
1156
1157int zeromap_page_range(struct vm_area_struct *vma,
1158 unsigned long addr, unsigned long size, pgprot_t prot)
1159{
1160 pgd_t *pgd;
1161 unsigned long next;
1162 unsigned long end = addr + size;
1163 struct mm_struct *mm = vma->vm_mm;
1164 int err;
1165
1166 BUG_ON(addr >= end);
1167 pgd = pgd_offset(mm, addr);
1168 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 do {
1170 next = pgd_addr_end(addr, end);
1171 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1172 if (err)
1173 break;
1174 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 return err;
1176}
1177
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001178pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001179{
1180 pgd_t * pgd = pgd_offset(mm, addr);
1181 pud_t * pud = pud_alloc(mm, pgd, addr);
1182 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001183 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001184 if (pmd)
1185 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1186 }
1187 return NULL;
1188}
1189
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001191 * This is the old fallback for page remapping.
1192 *
1193 * For historical reasons, it only allows reserved pages. Only
1194 * old drivers should use this, and they needed to mark their
1195 * pages reserved for the old functions anyway.
1196 */
1197static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
1198{
1199 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001200 pte_t *pte;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001201 spinlock_t *ptl;
1202
1203 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001204 if (PageAnon(page))
Linus Torvalds238f58d2005-11-29 13:01:56 -08001205 goto out;
1206 retval = -ENOMEM;
1207 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001208 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001209 if (!pte)
1210 goto out;
1211 retval = -EBUSY;
1212 if (!pte_none(*pte))
1213 goto out_unlock;
1214
1215 /* Ok, finally just insert the thing.. */
1216 get_page(page);
1217 inc_mm_counter(mm, file_rss);
1218 page_add_file_rmap(page);
1219 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1220
1221 retval = 0;
1222out_unlock:
1223 pte_unmap_unlock(pte, ptl);
1224out:
1225 return retval;
1226}
1227
1228/*
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001229 * This allows drivers to insert individual pages they've allocated
1230 * into a user vma.
1231 *
1232 * The page has to be a nice clean _individual_ kernel allocation.
1233 * If you allocate a compound page, you need to have marked it as
1234 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001235 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001236 *
1237 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1238 * took an arbitrary page protection parameter. This doesn't allow
1239 * that. Your vma protection will have to be set up correctly, which
1240 * means that if you want a shared writable mapping, you'd better
1241 * ask for a shared writable mapping!
1242 *
1243 * The page does not need to be reserved.
1244 */
1245int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1246{
1247 if (addr < vma->vm_start || addr >= vma->vm_end)
1248 return -EFAULT;
1249 if (!page_count(page))
1250 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001251 vma->vm_flags |= VM_INSERTPAGE;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001252 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1253}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001254EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001255
1256/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 * maps a range of physical memory into the requested pages. the old
1258 * mappings are removed. any references to nonexistent pages results
1259 * in null mappings (currently treated as "copy-on-access")
1260 */
1261static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1262 unsigned long addr, unsigned long end,
1263 unsigned long pfn, pgprot_t prot)
1264{
1265 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001266 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267
Hugh Dickinsc74df322005-10-29 18:16:23 -07001268 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269 if (!pte)
1270 return -ENOMEM;
1271 do {
1272 BUG_ON(!pte_none(*pte));
Nick Pigginb5810032005-10-29 18:16:12 -07001273 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001274 pfn++;
1275 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001276 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277 return 0;
1278}
1279
1280static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1281 unsigned long addr, unsigned long end,
1282 unsigned long pfn, pgprot_t prot)
1283{
1284 pmd_t *pmd;
1285 unsigned long next;
1286
1287 pfn -= addr >> PAGE_SHIFT;
1288 pmd = pmd_alloc(mm, pud, addr);
1289 if (!pmd)
1290 return -ENOMEM;
1291 do {
1292 next = pmd_addr_end(addr, end);
1293 if (remap_pte_range(mm, pmd, addr, next,
1294 pfn + (addr >> PAGE_SHIFT), prot))
1295 return -ENOMEM;
1296 } while (pmd++, addr = next, addr != end);
1297 return 0;
1298}
1299
1300static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1301 unsigned long addr, unsigned long end,
1302 unsigned long pfn, pgprot_t prot)
1303{
1304 pud_t *pud;
1305 unsigned long next;
1306
1307 pfn -= addr >> PAGE_SHIFT;
1308 pud = pud_alloc(mm, pgd, addr);
1309 if (!pud)
1310 return -ENOMEM;
1311 do {
1312 next = pud_addr_end(addr, end);
1313 if (remap_pmd_range(mm, pud, addr, next,
1314 pfn + (addr >> PAGE_SHIFT), prot))
1315 return -ENOMEM;
1316 } while (pud++, addr = next, addr != end);
1317 return 0;
1318}
1319
1320/* Note: this is only safe if the mm semaphore is held when called. */
1321int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1322 unsigned long pfn, unsigned long size, pgprot_t prot)
1323{
1324 pgd_t *pgd;
1325 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001326 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 struct mm_struct *mm = vma->vm_mm;
1328 int err;
1329
1330 /*
1331 * Physically remapped pages are special. Tell the
1332 * rest of the world about it:
1333 * VM_IO tells people not to look at these pages
1334 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001335 * VM_RESERVED is specified all over the place, because
1336 * in 2.4 it kept swapout's vma scan off this vma; but
1337 * in 2.6 the LRU scan won't even find its pages, so this
1338 * flag means no more than count its pages in reserved_vm,
1339 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001340 * VM_PFNMAP tells the core MM that the base pages are just
1341 * raw PFN mappings, and do not have a "struct page" associated
1342 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001343 *
1344 * There's a horrible special case to handle copy-on-write
1345 * behaviour that some programs depend on. We mark the "original"
1346 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 */
Linus Torvalds67121172005-12-11 20:38:17 -08001348 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001349 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001350 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001351 vma->vm_pgoff = pfn;
1352 }
1353
Linus Torvalds6aab3412005-11-28 14:34:23 -08001354 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355
1356 BUG_ON(addr >= end);
1357 pfn -= addr >> PAGE_SHIFT;
1358 pgd = pgd_offset(mm, addr);
1359 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001360 do {
1361 next = pgd_addr_end(addr, end);
1362 err = remap_pud_range(mm, pgd, addr, next,
1363 pfn + (addr >> PAGE_SHIFT), prot);
1364 if (err)
1365 break;
1366 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001367 return err;
1368}
1369EXPORT_SYMBOL(remap_pfn_range);
1370
1371/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001372 * handle_pte_fault chooses page fault handler according to an entry
1373 * which was read non-atomically. Before making any commitment, on
1374 * those architectures or configurations (e.g. i386 with PAE) which
1375 * might give a mix of unmatched parts, do_swap_page and do_file_page
1376 * must check under lock before unmapping the pte and proceeding
1377 * (but do_wp_page is only called after already making such a check;
1378 * and do_anonymous_page and do_no_page can safely check later on).
1379 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001380static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001381 pte_t *page_table, pte_t orig_pte)
1382{
1383 int same = 1;
1384#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1385 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001386 spinlock_t *ptl = pte_lockptr(mm, pmd);
1387 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001388 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001389 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001390 }
1391#endif
1392 pte_unmap(page_table);
1393 return same;
1394}
1395
1396/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001397 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1398 * servicing faults for write access. In the normal case, do always want
1399 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1400 * that do not have writing enabled, when used by access_process_vm.
1401 */
1402static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1403{
1404 if (likely(vma->vm_flags & VM_WRITE))
1405 pte = pte_mkwrite(pte);
1406 return pte;
1407}
1408
Linus Torvalds6aab3412005-11-28 14:34:23 -08001409static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
1410{
1411 /*
1412 * If the source page was a PFN mapping, we don't have
1413 * a "struct page" for it. We do a best-effort copy by
1414 * just copying from the original user address. If that
1415 * fails, we just zero-fill it. Live with it.
1416 */
1417 if (unlikely(!src)) {
1418 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2db2005-11-29 14:07:55 -08001419 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1420
1421 /*
1422 * This really shouldn't fail, because the page is there
1423 * in the page tables. But it might just be unreadable,
1424 * in which case we just give up and fill the result with
1425 * zeroes.
1426 */
1427 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001428 memset(kaddr, 0, PAGE_SIZE);
1429 kunmap_atomic(kaddr, KM_USER0);
1430 return;
1431
1432 }
1433 copy_user_highpage(dst, src, va);
1434}
1435
Linus Torvalds1da177e2005-04-16 15:20:36 -07001436/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437 * This routine handles present pages, when users try to write
1438 * to a shared page. It is done by copying the page to a new address
1439 * and decrementing the shared-page counter for the old page.
1440 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441 * Note that this routine assumes that the protection checks have been
1442 * done by the caller (the low-level page fault routine in most cases).
1443 * Thus we can safely just mark it writable once we've done any necessary
1444 * COW.
1445 *
1446 * We also mark the page dirty at this point even though the page will
1447 * change only once the write actually happens. This avoids a few races,
1448 * and potentially makes it more efficient.
1449 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001450 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1451 * but allow concurrent faults), with pte both mapped and locked.
1452 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001454static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1455 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001456 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001458 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 pte_t entry;
David Howells9637a5e2006-06-23 02:03:43 -07001460 int reuse, ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461
Linus Torvalds6aab3412005-11-28 14:34:23 -08001462 old_page = vm_normal_page(vma, address, orig_pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001463 if (!old_page)
1464 goto gotten;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001465
David Howells9637a5e2006-06-23 02:03:43 -07001466 if (unlikely((vma->vm_flags & (VM_SHARED|VM_WRITE)) ==
1467 (VM_SHARED|VM_WRITE))) {
1468 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
1469 /*
1470 * Notify the address space that the page is about to
1471 * become writable so that it can prohibit this or wait
1472 * for the page to get into an appropriate state.
1473 *
1474 * We do this without the lock held, so that it can
1475 * sleep if it needs to.
1476 */
1477 page_cache_get(old_page);
1478 pte_unmap_unlock(page_table, ptl);
1479
1480 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
1481 goto unwritable_page;
1482
1483 page_cache_release(old_page);
1484
1485 /*
1486 * Since we dropped the lock we need to revalidate
1487 * the PTE as someone else may have changed it. If
1488 * they did, we just return, as we can count on the
1489 * MMU to tell us if they didn't also make it writable.
1490 */
1491 page_table = pte_offset_map_lock(mm, pmd, address,
1492 &ptl);
1493 if (!pte_same(*page_table, orig_pte))
1494 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001495 }
David Howells9637a5e2006-06-23 02:03:43 -07001496
1497 reuse = 1;
1498 } else if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
1499 reuse = can_share_swap_page(old_page);
1500 unlock_page(old_page);
1501 } else {
1502 reuse = 0;
1503 }
1504
1505 if (reuse) {
1506 flush_cache_page(vma, address, pte_pfn(orig_pte));
1507 entry = pte_mkyoung(orig_pte);
1508 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1509 ptep_set_access_flags(vma, address, page_table, entry, 1);
1510 update_mmu_cache(vma, address, entry);
1511 lazy_mmu_prot_update(entry);
1512 ret |= VM_FAULT_WRITE;
1513 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001515
1516 /*
1517 * Ok, we need to copy. Oh, well..
1518 */
Nick Pigginb5810032005-10-29 18:16:12 -07001519 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001520gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001521 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001522
1523 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001524 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001525 if (old_page == ZERO_PAGE(address)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 new_page = alloc_zeroed_user_highpage(vma, address);
1527 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001528 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001529 } else {
1530 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1531 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001532 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001533 cow_user_page(new_page, old_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001534 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001535
Linus Torvalds1da177e2005-04-16 15:20:36 -07001536 /*
1537 * Re-check the pte - we dropped the lock
1538 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001539 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001540 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001541 if (old_page) {
1542 page_remove_rmap(old_page);
1543 if (!PageAnon(old_page)) {
1544 dec_mm_counter(mm, file_rss);
1545 inc_mm_counter(mm, anon_rss);
1546 }
1547 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001548 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001549 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001550 entry = mk_pte(new_page, vma->vm_page_prot);
1551 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1552 ptep_establish(vma, address, page_table, entry);
1553 update_mmu_cache(vma, address, entry);
1554 lazy_mmu_prot_update(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001555 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08001556 page_add_new_anon_rmap(new_page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001557
1558 /* Free the old page.. */
1559 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001560 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001561 }
Hugh Dickins920fc352005-11-21 21:32:17 -08001562 if (new_page)
1563 page_cache_release(new_page);
1564 if (old_page)
1565 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001566unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001567 pte_unmap_unlock(page_table, ptl);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001568 return ret;
Hugh Dickins65500d22005-10-29 18:15:59 -07001569oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001570 if (old_page)
1571 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07001573
1574unwritable_page:
1575 page_cache_release(old_page);
1576 return VM_FAULT_SIGBUS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001577}
1578
1579/*
1580 * Helper functions for unmap_mapping_range().
1581 *
1582 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1583 *
1584 * We have to restart searching the prio_tree whenever we drop the lock,
1585 * since the iterator is only valid while the lock is held, and anyway
1586 * a later vma might be split and reinserted earlier while lock dropped.
1587 *
1588 * The list of nonlinear vmas could be handled more efficiently, using
1589 * a placeholder, but handle it in the same way until a need is shown.
1590 * It is important to search the prio_tree before nonlinear list: a vma
1591 * may become nonlinear and be shifted from prio_tree to nonlinear list
1592 * while the lock is dropped; but never shifted from list to prio_tree.
1593 *
1594 * In order to make forward progress despite restarting the search,
1595 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1596 * quickly skip it next time around. Since the prio_tree search only
1597 * shows us those vmas affected by unmapping the range in question, we
1598 * can't efficiently keep all vmas in step with mapping->truncate_count:
1599 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1600 * mapping->truncate_count and vma->vm_truncate_count are protected by
1601 * i_mmap_lock.
1602 *
1603 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001604 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001605 * and restart from that address when we reach that vma again. It might
1606 * have been split or merged, shrunk or extended, but never shifted: so
1607 * restart_addr remains valid so long as it remains in the vma's range.
1608 * unmap_mapping_range forces truncate_count to leap over page-aligned
1609 * values so we can save vma's restart_addr in its truncate_count field.
1610 */
1611#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1612
1613static void reset_vma_truncate_counts(struct address_space *mapping)
1614{
1615 struct vm_area_struct *vma;
1616 struct prio_tree_iter iter;
1617
1618 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1619 vma->vm_truncate_count = 0;
1620 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1621 vma->vm_truncate_count = 0;
1622}
1623
1624static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1625 unsigned long start_addr, unsigned long end_addr,
1626 struct zap_details *details)
1627{
1628 unsigned long restart_addr;
1629 int need_break;
1630
1631again:
1632 restart_addr = vma->vm_truncate_count;
1633 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1634 start_addr = restart_addr;
1635 if (start_addr >= end_addr) {
1636 /* Top of vma has been split off since last time */
1637 vma->vm_truncate_count = details->truncate_count;
1638 return 0;
1639 }
1640 }
1641
Hugh Dickinsee39b372005-04-19 13:29:15 -07001642 restart_addr = zap_page_range(vma, start_addr,
1643 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001644 need_break = need_resched() ||
1645 need_lockbreak(details->i_mmap_lock);
1646
Hugh Dickinsee39b372005-04-19 13:29:15 -07001647 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001648 /* We have now completed this vma: mark it so */
1649 vma->vm_truncate_count = details->truncate_count;
1650 if (!need_break)
1651 return 0;
1652 } else {
1653 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001654 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001655 if (!need_break)
1656 goto again;
1657 }
1658
1659 spin_unlock(details->i_mmap_lock);
1660 cond_resched();
1661 spin_lock(details->i_mmap_lock);
1662 return -EINTR;
1663}
1664
1665static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1666 struct zap_details *details)
1667{
1668 struct vm_area_struct *vma;
1669 struct prio_tree_iter iter;
1670 pgoff_t vba, vea, zba, zea;
1671
1672restart:
1673 vma_prio_tree_foreach(vma, &iter, root,
1674 details->first_index, details->last_index) {
1675 /* Skip quickly over those we have already dealt with */
1676 if (vma->vm_truncate_count == details->truncate_count)
1677 continue;
1678
1679 vba = vma->vm_pgoff;
1680 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1681 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1682 zba = details->first_index;
1683 if (zba < vba)
1684 zba = vba;
1685 zea = details->last_index;
1686 if (zea > vea)
1687 zea = vea;
1688
1689 if (unmap_mapping_range_vma(vma,
1690 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1691 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1692 details) < 0)
1693 goto restart;
1694 }
1695}
1696
1697static inline void unmap_mapping_range_list(struct list_head *head,
1698 struct zap_details *details)
1699{
1700 struct vm_area_struct *vma;
1701
1702 /*
1703 * In nonlinear VMAs there is no correspondence between virtual address
1704 * offset and file offset. So we must perform an exhaustive search
1705 * across *all* the pages in each nonlinear VMA, not just the pages
1706 * whose virtual address lies outside the file truncation point.
1707 */
1708restart:
1709 list_for_each_entry(vma, head, shared.vm_set.list) {
1710 /* Skip quickly over those we have already dealt with */
1711 if (vma->vm_truncate_count == details->truncate_count)
1712 continue;
1713 details->nonlinear_vma = vma;
1714 if (unmap_mapping_range_vma(vma, vma->vm_start,
1715 vma->vm_end, details) < 0)
1716 goto restart;
1717 }
1718}
1719
1720/**
1721 * unmap_mapping_range - unmap the portion of all mmaps
1722 * in the specified address_space corresponding to the specified
1723 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001724 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725 * @holebegin: byte in first page to unmap, relative to the start of
1726 * the underlying file. This will be rounded down to a PAGE_SIZE
1727 * boundary. Note that this is different from vmtruncate(), which
1728 * must keep the partial page. In contrast, we must get rid of
1729 * partial pages.
1730 * @holelen: size of prospective hole in bytes. This will be rounded
1731 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1732 * end of the file.
1733 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1734 * but 0 when invalidating pagecache, don't throw away private data.
1735 */
1736void unmap_mapping_range(struct address_space *mapping,
1737 loff_t const holebegin, loff_t const holelen, int even_cows)
1738{
1739 struct zap_details details;
1740 pgoff_t hba = holebegin >> PAGE_SHIFT;
1741 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1742
1743 /* Check for overflow. */
1744 if (sizeof(holelen) > sizeof(hlen)) {
1745 long long holeend =
1746 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1747 if (holeend & ~(long long)ULONG_MAX)
1748 hlen = ULONG_MAX - hba + 1;
1749 }
1750
1751 details.check_mapping = even_cows? NULL: mapping;
1752 details.nonlinear_vma = NULL;
1753 details.first_index = hba;
1754 details.last_index = hba + hlen - 1;
1755 if (details.last_index < details.first_index)
1756 details.last_index = ULONG_MAX;
1757 details.i_mmap_lock = &mapping->i_mmap_lock;
1758
1759 spin_lock(&mapping->i_mmap_lock);
1760
1761 /* serialize i_size write against truncate_count write */
1762 smp_wmb();
1763 /* Protect against page faults, and endless unmapping loops */
1764 mapping->truncate_count++;
1765 /*
1766 * For archs where spin_lock has inclusive semantics like ia64
1767 * this smp_mb() will prevent to read pagetable contents
1768 * before the truncate_count increment is visible to
1769 * other cpus.
1770 */
1771 smp_mb();
1772 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1773 if (mapping->truncate_count == 0)
1774 reset_vma_truncate_counts(mapping);
1775 mapping->truncate_count++;
1776 }
1777 details.truncate_count = mapping->truncate_count;
1778
1779 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1780 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1781 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1782 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1783 spin_unlock(&mapping->i_mmap_lock);
1784}
1785EXPORT_SYMBOL(unmap_mapping_range);
1786
1787/*
1788 * Handle all mappings that got truncated by a "truncate()"
1789 * system call.
1790 *
1791 * NOTE! We have to be ready to update the memory sharing
1792 * between the file and the memory map for a potential last
1793 * incomplete page. Ugly, but necessary.
1794 */
1795int vmtruncate(struct inode * inode, loff_t offset)
1796{
1797 struct address_space *mapping = inode->i_mapping;
1798 unsigned long limit;
1799
1800 if (inode->i_size < offset)
1801 goto do_expand;
1802 /*
1803 * truncation of in-use swapfiles is disallowed - it would cause
1804 * subsequent swapout to scribble on the now-freed blocks.
1805 */
1806 if (IS_SWAPFILE(inode))
1807 goto out_busy;
1808 i_size_write(inode, offset);
1809 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1810 truncate_inode_pages(mapping, offset);
1811 goto out_truncate;
1812
1813do_expand:
1814 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1815 if (limit != RLIM_INFINITY && offset > limit)
1816 goto out_sig;
1817 if (offset > inode->i_sb->s_maxbytes)
1818 goto out_big;
1819 i_size_write(inode, offset);
1820
1821out_truncate:
1822 if (inode->i_op && inode->i_op->truncate)
1823 inode->i_op->truncate(inode);
1824 return 0;
1825out_sig:
1826 send_sig(SIGXFSZ, current, 0);
1827out_big:
1828 return -EFBIG;
1829out_busy:
1830 return -ETXTBSY;
1831}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001832EXPORT_SYMBOL(vmtruncate);
1833
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001834int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
1835{
1836 struct address_space *mapping = inode->i_mapping;
1837
1838 /*
1839 * If the underlying filesystem is not going to provide
1840 * a way to truncate a range of blocks (punch a hole) -
1841 * we should return failure right now.
1842 */
1843 if (!inode->i_op || !inode->i_op->truncate_range)
1844 return -ENOSYS;
1845
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001846 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001847 down_write(&inode->i_alloc_sem);
1848 unmap_mapping_range(mapping, offset, (end - offset), 1);
1849 truncate_inode_pages_range(mapping, offset, end);
1850 inode->i_op->truncate_range(inode, offset, end);
1851 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001852 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001853
1854 return 0;
1855}
1856EXPORT_SYMBOL(vmtruncate_range);
1857
Linus Torvalds1da177e2005-04-16 15:20:36 -07001858/*
1859 * Primitive swap readahead code. We simply read an aligned block of
1860 * (1 << page_cluster) entries in the swap area. This method is chosen
1861 * because it doesn't cost us any seek time. We also make sure to queue
1862 * the 'original' request together with the readahead ones...
1863 *
1864 * This has been extended to use the NUMA policies from the mm triggering
1865 * the readahead.
1866 *
1867 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1868 */
1869void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1870{
1871#ifdef CONFIG_NUMA
1872 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1873#endif
1874 int i, num;
1875 struct page *new_page;
1876 unsigned long offset;
1877
1878 /*
1879 * Get the number of handles we should do readahead io to.
1880 */
1881 num = valid_swaphandles(entry, &offset);
1882 for (i = 0; i < num; offset++, i++) {
1883 /* Ok, do the async read-ahead now */
1884 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1885 offset), vma, addr);
1886 if (!new_page)
1887 break;
1888 page_cache_release(new_page);
1889#ifdef CONFIG_NUMA
1890 /*
1891 * Find the next applicable VMA for the NUMA policy.
1892 */
1893 addr += PAGE_SIZE;
1894 if (addr == 0)
1895 vma = NULL;
1896 if (vma) {
1897 if (addr >= vma->vm_end) {
1898 vma = next_vma;
1899 next_vma = vma ? vma->vm_next : NULL;
1900 }
1901 if (vma && addr < vma->vm_start)
1902 vma = NULL;
1903 } else {
1904 if (next_vma && addr >= next_vma->vm_start) {
1905 vma = next_vma;
1906 next_vma = vma->vm_next;
1907 }
1908 }
1909#endif
1910 }
1911 lru_add_drain(); /* Push any new pages onto the LRU now */
1912}
1913
1914/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001915 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1916 * but allow concurrent faults), and pte mapped but not yet locked.
1917 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001918 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001919static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1920 unsigned long address, pte_t *page_table, pmd_t *pmd,
1921 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001922{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001923 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001925 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926 pte_t pte;
1927 int ret = VM_FAULT_MINOR;
1928
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001929 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001930 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07001931
1932 entry = pte_to_swp_entry(orig_pte);
Christoph Lameter06972122006-06-23 02:03:35 -07001933 if (is_migration_entry(entry)) {
1934 migration_entry_wait(mm, pmd, address);
1935 goto out;
1936 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 page = lookup_swap_cache(entry);
1938 if (!page) {
1939 swapin_readahead(entry, address, vma);
1940 page = read_swap_cache_async(entry, vma, address);
1941 if (!page) {
1942 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001943 * Back out if somebody else faulted in this pte
1944 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001946 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947 if (likely(pte_same(*page_table, orig_pte)))
1948 ret = VM_FAULT_OOM;
Hugh Dickins65500d22005-10-29 18:15:59 -07001949 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001950 }
1951
1952 /* Had to read the page from swap area: Major fault */
1953 ret = VM_FAULT_MAJOR;
1954 inc_page_state(pgmajfault);
1955 grab_swap_token();
1956 }
1957
1958 mark_page_accessed(page);
1959 lock_page(page);
1960
1961 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001962 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001963 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001964 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07001965 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07001966 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001967
1968 if (unlikely(!PageUptodate(page))) {
1969 ret = VM_FAULT_SIGBUS;
1970 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001971 }
1972
1973 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974
Hugh Dickins42946212005-10-29 18:16:05 -07001975 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976 pte = mk_pte(page, vma->vm_page_prot);
1977 if (write_access && can_share_swap_page(page)) {
1978 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1979 write_access = 0;
1980 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001981
1982 flush_icache_page(vma, page);
1983 set_pte_at(mm, address, page_table, pte);
1984 page_add_anon_rmap(page, vma, address);
1985
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001986 swap_free(entry);
1987 if (vm_swap_full())
1988 remove_exclusive_swap_page(page);
1989 unlock_page(page);
1990
Linus Torvalds1da177e2005-04-16 15:20:36 -07001991 if (write_access) {
1992 if (do_wp_page(mm, vma, address,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001993 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 ret = VM_FAULT_OOM;
1995 goto out;
1996 }
1997
1998 /* No need to invalidate - it was non-present before */
1999 update_mmu_cache(vma, address, pte);
2000 lazy_mmu_prot_update(pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07002001unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002002 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002003out:
2004 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002005out_nomap:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002006 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07002007 unlock_page(page);
2008 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002009 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010}
2011
2012/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002013 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2014 * but allow concurrent faults), and pte mapped but not yet locked.
2015 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002016 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002017static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2018 unsigned long address, pte_t *page_table, pmd_t *pmd,
2019 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002021 struct page *page;
2022 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002023 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024
Linus Torvalds6aab3412005-11-28 14:34:23 -08002025 if (write_access) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002026 /* Allocate our own private page. */
2027 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028
2029 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07002030 goto oom;
2031 page = alloc_zeroed_user_highpage(vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032 if (!page)
Hugh Dickins65500d22005-10-29 18:15:59 -07002033 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034
Hugh Dickins65500d22005-10-29 18:15:59 -07002035 entry = mk_pte(page, vma->vm_page_prot);
2036 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002037
2038 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2039 if (!pte_none(*page_table))
2040 goto release;
2041 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002042 lru_cache_add_active(page);
Nick Piggin9617d952006-01-06 00:11:12 -08002043 page_add_new_anon_rmap(page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07002044 } else {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002045 /* Map the ZERO_PAGE - vm_page_prot is readonly */
2046 page = ZERO_PAGE(address);
2047 page_cache_get(page);
2048 entry = mk_pte(page, vma->vm_page_prot);
2049
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002050 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002051 spin_lock(ptl);
2052 if (!pte_none(*page_table))
2053 goto release;
Nick Pigginb5810032005-10-29 18:16:12 -07002054 inc_mm_counter(mm, file_rss);
2055 page_add_file_rmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002056 }
2057
Hugh Dickins65500d22005-10-29 18:15:59 -07002058 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002059
2060 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002061 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002063unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002064 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065 return VM_FAULT_MINOR;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002066release:
2067 page_cache_release(page);
2068 goto unlock;
Hugh Dickins65500d22005-10-29 18:15:59 -07002069oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 return VM_FAULT_OOM;
2071}
2072
2073/*
2074 * do_no_page() tries to create a new page mapping. It aggressively
2075 * tries to share with existing pages, but makes a separate copy if
2076 * the "write_access" parameter is true in order to avoid the next
2077 * page fault.
2078 *
2079 * As this is called only for pages that do not currently exist, we
2080 * do not need to flush old virtual caches or the TLB.
2081 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002082 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2083 * but allow concurrent faults), and pte mapped but not yet locked.
2084 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002086static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2087 unsigned long address, pte_t *page_table, pmd_t *pmd,
2088 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002090 spinlock_t *ptl;
Hugh Dickins65500d22005-10-29 18:15:59 -07002091 struct page *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002092 struct address_space *mapping = NULL;
2093 pte_t entry;
2094 unsigned int sequence = 0;
2095 int ret = VM_FAULT_MINOR;
2096 int anon = 0;
2097
Linus Torvalds1da177e2005-04-16 15:20:36 -07002098 pte_unmap(page_table);
Hugh Dickins325f04d2005-11-29 16:55:48 +00002099 BUG_ON(vma->vm_flags & VM_PFNMAP);
2100
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101 if (vma->vm_file) {
2102 mapping = vma->vm_file->f_mapping;
2103 sequence = mapping->truncate_count;
2104 smp_rmb(); /* serializes i_size against truncate_count */
2105 }
2106retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2108 /*
2109 * No smp_rmb is needed here as long as there's a full
2110 * spin_lock/unlock sequence inside the ->nopage callback
2111 * (for the pagecache lookup) that acts as an implicit
2112 * smp_mb() and prevents the i_size read to happen
2113 * after the next truncate_count read.
2114 */
2115
2116 /* no page was available -- either SIGBUS or OOM */
2117 if (new_page == NOPAGE_SIGBUS)
2118 return VM_FAULT_SIGBUS;
2119 if (new_page == NOPAGE_OOM)
2120 return VM_FAULT_OOM;
2121
2122 /*
2123 * Should we do an early C-O-W break?
2124 */
David Howells9637a5e2006-06-23 02:03:43 -07002125 if (write_access) {
2126 if (!(vma->vm_flags & VM_SHARED)) {
2127 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002128
David Howells9637a5e2006-06-23 02:03:43 -07002129 if (unlikely(anon_vma_prepare(vma)))
2130 goto oom;
2131 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
2132 if (!page)
2133 goto oom;
2134 copy_user_highpage(page, new_page, address);
2135 page_cache_release(new_page);
2136 new_page = page;
2137 anon = 1;
2138
2139 } else {
2140 /* if the page will be shareable, see if the backing
2141 * address space wants to know that the page is about
2142 * to become writable */
2143 if (vma->vm_ops->page_mkwrite &&
2144 vma->vm_ops->page_mkwrite(vma, new_page) < 0
2145 ) {
2146 page_cache_release(new_page);
2147 return VM_FAULT_SIGBUS;
2148 }
2149 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002150 }
2151
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002152 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002153 /*
2154 * For a file-backed vma, someone could have truncated or otherwise
2155 * invalidated this page. If unmap_mapping_range got called,
2156 * retry getting the page.
2157 */
2158 if (mapping && unlikely(sequence != mapping->truncate_count)) {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002159 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002161 cond_resched();
2162 sequence = mapping->truncate_count;
2163 smp_rmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164 goto retry;
2165 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002166
2167 /*
2168 * This silly early PAGE_DIRTY setting removes a race
2169 * due to the bad i386 page protection. But it's valid
2170 * for other architectures too.
2171 *
2172 * Note that if write_access is true, we either now have
2173 * an exclusive copy of the page, or this is a shared mapping,
2174 * so we can make it writable and dirty to avoid having to
2175 * handle that later.
2176 */
2177 /* Only go through if we didn't race with anybody else... */
2178 if (pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 flush_icache_page(vma, new_page);
2180 entry = mk_pte(new_page, vma->vm_page_prot);
2181 if (write_access)
2182 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2183 set_pte_at(mm, address, page_table, entry);
2184 if (anon) {
Hugh Dickins42946212005-10-29 18:16:05 -07002185 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002186 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08002187 page_add_new_anon_rmap(new_page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002188 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002189 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 page_add_file_rmap(new_page);
Hugh Dickins42946212005-10-29 18:16:05 -07002191 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002192 } else {
2193 /* One of our sibling threads was faster, back out. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002194 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002195 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002196 }
2197
2198 /* no need to invalidate: a not-present page shouldn't be cached */
2199 update_mmu_cache(vma, address, entry);
2200 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002201unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002202 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002203 return ret;
2204oom:
2205 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002206 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207}
2208
2209/*
2210 * Fault of a previously existing named mapping. Repopulate the pte
2211 * from the encoded file_pte if possible. This enables swappable
2212 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002213 *
2214 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2215 * but allow concurrent faults), and pte mapped but not yet locked.
2216 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002217 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002218static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
2219 unsigned long address, pte_t *page_table, pmd_t *pmd,
2220 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221{
Hugh Dickins65500d22005-10-29 18:15:59 -07002222 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223 int err;
2224
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002225 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002226 return VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002227
Hugh Dickins65500d22005-10-29 18:15:59 -07002228 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
2229 /*
2230 * Page table corrupted: show pte and kill process.
2231 */
Nick Pigginb5810032005-10-29 18:16:12 -07002232 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002233 return VM_FAULT_OOM;
2234 }
2235 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2236
2237 pgoff = pte_to_pgoff(orig_pte);
2238 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
2239 vma->vm_page_prot, pgoff, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240 if (err == -ENOMEM)
2241 return VM_FAULT_OOM;
2242 if (err)
2243 return VM_FAULT_SIGBUS;
2244 return VM_FAULT_MAJOR;
2245}
2246
2247/*
2248 * These routines also need to handle stuff like marking pages dirty
2249 * and/or accessed for architectures that don't do it in hardware (most
2250 * RISC architectures). The early dirtying is also good on the i386.
2251 *
2252 * There is also a hook called "update_mmu_cache()" that architectures
2253 * with external mmu caches can use to update those (ie the Sparc or
2254 * PowerPC hashed page tables that act as extended TLBs).
2255 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002256 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2257 * but allow concurrent faults), and pte mapped but not yet locked.
2258 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002259 */
2260static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002261 struct vm_area_struct *vma, unsigned long address,
2262 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002263{
2264 pte_t entry;
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002265 pte_t old_entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002266 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002268 old_entry = entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002269 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002270 if (pte_none(entry)) {
2271 if (!vma->vm_ops || !vma->vm_ops->nopage)
2272 return do_anonymous_page(mm, vma, address,
2273 pte, pmd, write_access);
2274 return do_no_page(mm, vma, address,
2275 pte, pmd, write_access);
2276 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002277 if (pte_file(entry))
Hugh Dickins65500d22005-10-29 18:15:59 -07002278 return do_file_page(mm, vma, address,
2279 pte, pmd, write_access, entry);
2280 return do_swap_page(mm, vma, address,
2281 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282 }
2283
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002284 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002285 spin_lock(ptl);
2286 if (unlikely(!pte_same(*pte, entry)))
2287 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288 if (write_access) {
2289 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002290 return do_wp_page(mm, vma, address,
2291 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002292 entry = pte_mkdirty(entry);
2293 }
2294 entry = pte_mkyoung(entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002295 if (!pte_same(old_entry, entry)) {
2296 ptep_set_access_flags(vma, address, pte, entry, write_access);
2297 update_mmu_cache(vma, address, entry);
2298 lazy_mmu_prot_update(entry);
2299 } else {
2300 /*
2301 * This is needed only for protection faults but the arch code
2302 * is not yet telling us if this is a protection fault or not.
2303 * This still avoids useless tlb flushes for .text page faults
2304 * with threads.
2305 */
2306 if (write_access)
2307 flush_tlb_page(vma, address);
2308 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002309unlock:
2310 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002311 return VM_FAULT_MINOR;
2312}
2313
2314/*
2315 * By the time we get here, we already hold the mm semaphore
2316 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002317int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318 unsigned long address, int write_access)
2319{
2320 pgd_t *pgd;
2321 pud_t *pud;
2322 pmd_t *pmd;
2323 pte_t *pte;
2324
2325 __set_current_state(TASK_RUNNING);
2326
2327 inc_page_state(pgfault);
2328
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002329 if (unlikely(is_vm_hugetlb_page(vma)))
2330 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331
Linus Torvalds1da177e2005-04-16 15:20:36 -07002332 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333 pud = pud_alloc(mm, pgd, address);
2334 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002335 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336 pmd = pmd_alloc(mm, pud, address);
2337 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002338 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339 pte = pte_alloc_map(mm, pmd, address);
2340 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002341 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002342
Hugh Dickinsc74df322005-10-29 18:16:23 -07002343 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002344}
2345
Arnd Bergmann67207b92005-11-15 15:53:48 -05002346EXPORT_SYMBOL_GPL(__handle_mm_fault);
2347
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348#ifndef __PAGETABLE_PUD_FOLDED
2349/*
2350 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002351 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002353int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002354{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002355 pud_t *new = pud_alloc_one(mm, address);
2356 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002357 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358
Hugh Dickins872fec12005-10-29 18:16:21 -07002359 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002360 if (pgd_present(*pgd)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 pud_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002362 else
2363 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002364 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002365 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002366}
Alan Sterne0f39592005-11-28 13:43:44 -08002367#else
2368/* Workaround for gcc 2.96 */
2369int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2370{
2371 return 0;
2372}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373#endif /* __PAGETABLE_PUD_FOLDED */
2374
2375#ifndef __PAGETABLE_PMD_FOLDED
2376/*
2377 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002378 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002379 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002380int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002381{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002382 pmd_t *new = pmd_alloc_one(mm, address);
2383 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002384 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002385
Hugh Dickins872fec12005-10-29 18:16:21 -07002386 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002387#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002388 if (pud_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002389 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002390 else
2391 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002393 if (pgd_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002394 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002395 else
2396 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002397#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002398 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002399 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002400}
Alan Sterne0f39592005-11-28 13:43:44 -08002401#else
2402/* Workaround for gcc 2.96 */
2403int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2404{
2405 return 0;
2406}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407#endif /* __PAGETABLE_PMD_FOLDED */
2408
2409int make_pages_present(unsigned long addr, unsigned long end)
2410{
2411 int ret, len, write;
2412 struct vm_area_struct * vma;
2413
2414 vma = find_vma(current->mm, addr);
2415 if (!vma)
2416 return -1;
2417 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02002418 BUG_ON(addr >= end);
2419 BUG_ON(end > vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002420 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2421 ret = get_user_pages(current, current->mm, addr,
2422 len, write, 0, NULL, NULL);
2423 if (ret < 0)
2424 return ret;
2425 return ret == len ? 0 : -1;
2426}
2427
2428/*
2429 * Map a vmalloc()-space virtual address to the physical page.
2430 */
2431struct page * vmalloc_to_page(void * vmalloc_addr)
2432{
2433 unsigned long addr = (unsigned long) vmalloc_addr;
2434 struct page *page = NULL;
2435 pgd_t *pgd = pgd_offset_k(addr);
2436 pud_t *pud;
2437 pmd_t *pmd;
2438 pte_t *ptep, pte;
2439
2440 if (!pgd_none(*pgd)) {
2441 pud = pud_offset(pgd, addr);
2442 if (!pud_none(*pud)) {
2443 pmd = pmd_offset(pud, addr);
2444 if (!pmd_none(*pmd)) {
2445 ptep = pte_offset_map(pmd, addr);
2446 pte = *ptep;
2447 if (pte_present(pte))
2448 page = pte_page(pte);
2449 pte_unmap(ptep);
2450 }
2451 }
2452 }
2453 return page;
2454}
2455
2456EXPORT_SYMBOL(vmalloc_to_page);
2457
2458/*
2459 * Map a vmalloc()-space virtual address to the physical page frame number.
2460 */
2461unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2462{
2463 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2464}
2465
2466EXPORT_SYMBOL(vmalloc_to_pfn);
2467
Linus Torvalds1da177e2005-04-16 15:20:36 -07002468#if !defined(__HAVE_ARCH_GATE_AREA)
2469
2470#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002471static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002472
2473static int __init gate_vma_init(void)
2474{
2475 gate_vma.vm_mm = NULL;
2476 gate_vma.vm_start = FIXADDR_USER_START;
2477 gate_vma.vm_end = FIXADDR_USER_END;
2478 gate_vma.vm_page_prot = PAGE_READONLY;
Hugh Dickins0b14c172005-11-21 21:32:15 -08002479 gate_vma.vm_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002480 return 0;
2481}
2482__initcall(gate_vma_init);
2483#endif
2484
2485struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2486{
2487#ifdef AT_SYSINFO_EHDR
2488 return &gate_vma;
2489#else
2490 return NULL;
2491#endif
2492}
2493
2494int in_gate_area_no_task(unsigned long addr)
2495{
2496#ifdef AT_SYSINFO_EHDR
2497 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2498 return 1;
2499#endif
2500 return 0;
2501}
2502
2503#endif /* __HAVE_ARCH_GATE_AREA */