blob: 0ec7bc644271cf6ee2b88b7d32cc7987c5ea6dc6 [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)) {
437 swap_duplicate(pte_to_swp_entry(pte));
438 /* make sure dst_mm is on swapoff's mmlist. */
439 if (unlikely(list_empty(&dst_mm->mmlist))) {
440 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700441 if (list_empty(&dst_mm->mmlist))
442 list_add(&dst_mm->mmlist,
443 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444 spin_unlock(&mmlist_lock);
445 }
446 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700447 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 }
449
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 /*
451 * If it's a COW mapping, write protect it both
452 * in the parent and the child
453 */
Linus Torvalds67121172005-12-11 20:38:17 -0800454 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 ptep_set_wrprotect(src_mm, addr, src_pte);
456 pte = *src_pte;
457 }
458
459 /*
460 * If it's a shared mapping, mark it clean in
461 * the child
462 */
463 if (vm_flags & VM_SHARED)
464 pte = pte_mkclean(pte);
465 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800466
467 page = vm_normal_page(vma, addr, pte);
468 if (page) {
469 get_page(page);
470 page_dup_rmap(page);
471 rss[!!PageAnon(page)]++;
472 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700473
474out_set_pte:
475 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476}
477
478static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
479 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
480 unsigned long addr, unsigned long end)
481{
482 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700483 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700484 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700485 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486
487again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700488 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700489 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 if (!dst_pte)
491 return -ENOMEM;
492 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700493 src_ptl = pte_lockptr(src_mm, src_pmd);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700494 spin_lock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 do {
497 /*
498 * We are holding two locks at this point - either of them
499 * could generate latencies in another task on another CPU.
500 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700501 if (progress >= 32) {
502 progress = 0;
503 if (need_resched() ||
Hugh Dickinsc74df322005-10-29 18:16:23 -0700504 need_lockbreak(src_ptl) ||
505 need_lockbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700506 break;
507 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if (pte_none(*src_pte)) {
509 progress++;
510 continue;
511 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700512 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 progress += 8;
514 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700515
Hugh Dickinsc74df322005-10-29 18:16:23 -0700516 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700518 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700519 pte_unmap_unlock(dst_pte - 1, dst_ptl);
520 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 if (addr != end)
522 goto again;
523 return 0;
524}
525
526static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
527 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
528 unsigned long addr, unsigned long end)
529{
530 pmd_t *src_pmd, *dst_pmd;
531 unsigned long next;
532
533 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
534 if (!dst_pmd)
535 return -ENOMEM;
536 src_pmd = pmd_offset(src_pud, addr);
537 do {
538 next = pmd_addr_end(addr, end);
539 if (pmd_none_or_clear_bad(src_pmd))
540 continue;
541 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
542 vma, addr, next))
543 return -ENOMEM;
544 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
545 return 0;
546}
547
548static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
549 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
550 unsigned long addr, unsigned long end)
551{
552 pud_t *src_pud, *dst_pud;
553 unsigned long next;
554
555 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
556 if (!dst_pud)
557 return -ENOMEM;
558 src_pud = pud_offset(src_pgd, addr);
559 do {
560 next = pud_addr_end(addr, end);
561 if (pud_none_or_clear_bad(src_pud))
562 continue;
563 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
564 vma, addr, next))
565 return -ENOMEM;
566 } while (dst_pud++, src_pud++, addr = next, addr != end);
567 return 0;
568}
569
570int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
571 struct vm_area_struct *vma)
572{
573 pgd_t *src_pgd, *dst_pgd;
574 unsigned long next;
575 unsigned long addr = vma->vm_start;
576 unsigned long end = vma->vm_end;
577
Nick Piggind9928952005-08-28 16:49:11 +1000578 /*
579 * Don't copy ptes where a page fault will fill them correctly.
580 * Fork becomes much lighter when there are big shared or private
581 * readonly mappings. The tradeoff is that copy_page_range is more
582 * efficient than faulting.
583 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800584 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000585 if (!vma->anon_vma)
586 return 0;
587 }
588
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 if (is_vm_hugetlb_page(vma))
590 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
591
592 dst_pgd = pgd_offset(dst_mm, addr);
593 src_pgd = pgd_offset(src_mm, addr);
594 do {
595 next = pgd_addr_end(addr, end);
596 if (pgd_none_or_clear_bad(src_pgd))
597 continue;
598 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
599 vma, addr, next))
600 return -ENOMEM;
601 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
602 return 0;
603}
604
Robin Holt51c6f662005-11-13 16:06:42 -0800605static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700606 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800608 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609{
Nick Pigginb5810032005-10-29 18:16:12 -0700610 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700611 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700612 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700613 int file_rss = 0;
614 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615
Hugh Dickins508034a2005-10-29 18:16:30 -0700616 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 do {
618 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800619 if (pte_none(ptent)) {
620 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800622 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800623
624 (*zap_work) -= PAGE_SIZE;
625
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800627 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800628
Linus Torvalds6aab3412005-11-28 14:34:23 -0800629 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 if (unlikely(details) && page) {
631 /*
632 * unmap_shared_mapping_pages() wants to
633 * invalidate cache without truncating:
634 * unmap shared but keep private pages.
635 */
636 if (details->check_mapping &&
637 details->check_mapping != page->mapping)
638 continue;
639 /*
640 * Each page->index must be checked when
641 * invalidating or truncating nonlinear.
642 */
643 if (details->nonlinear_vma &&
644 (page->index < details->first_index ||
645 page->index > details->last_index))
646 continue;
647 }
Nick Pigginb5810032005-10-29 18:16:12 -0700648 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700649 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 tlb_remove_tlb_entry(tlb, pte, addr);
651 if (unlikely(!page))
652 continue;
653 if (unlikely(details) && details->nonlinear_vma
654 && linear_page_index(details->nonlinear_vma,
655 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700656 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700659 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700660 else {
661 if (pte_dirty(ptent))
662 set_page_dirty(page);
663 if (pte_young(ptent))
664 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700665 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700666 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 page_remove_rmap(page);
668 tlb_remove_page(tlb, page);
669 continue;
670 }
671 /*
672 * If details->check_mapping, we leave swap entries;
673 * if details->nonlinear_vma, we leave file entries.
674 */
675 if (unlikely(details))
676 continue;
677 if (!pte_file(ptent))
678 free_swap_and_cache(pte_to_swp_entry(ptent));
Nick Pigginb5810032005-10-29 18:16:12 -0700679 pte_clear_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800680 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700681
Hugh Dickins86d912f2005-10-29 18:16:14 -0700682 add_mm_rss(mm, file_rss, anon_rss);
Hugh Dickins508034a2005-10-29 18:16:30 -0700683 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800684
685 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686}
687
Robin Holt51c6f662005-11-13 16:06:42 -0800688static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700689 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800691 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692{
693 pmd_t *pmd;
694 unsigned long next;
695
696 pmd = pmd_offset(pud, addr);
697 do {
698 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800699 if (pmd_none_or_clear_bad(pmd)) {
700 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700701 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800702 }
703 next = zap_pte_range(tlb, vma, pmd, addr, next,
704 zap_work, details);
705 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
706
707 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708}
709
Robin Holt51c6f662005-11-13 16:06:42 -0800710static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700711 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800713 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714{
715 pud_t *pud;
716 unsigned long next;
717
718 pud = pud_offset(pgd, addr);
719 do {
720 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800721 if (pud_none_or_clear_bad(pud)) {
722 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800724 }
725 next = zap_pmd_range(tlb, vma, pud, addr, next,
726 zap_work, details);
727 } while (pud++, addr = next, (addr != end && *zap_work > 0));
728
729 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730}
731
Robin Holt51c6f662005-11-13 16:06:42 -0800732static unsigned long unmap_page_range(struct mmu_gather *tlb,
733 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800735 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736{
737 pgd_t *pgd;
738 unsigned long next;
739
740 if (details && !details->check_mapping && !details->nonlinear_vma)
741 details = NULL;
742
743 BUG_ON(addr >= end);
744 tlb_start_vma(tlb, vma);
745 pgd = pgd_offset(vma->vm_mm, addr);
746 do {
747 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800748 if (pgd_none_or_clear_bad(pgd)) {
749 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800751 }
752 next = zap_pud_range(tlb, vma, pgd, addr, next,
753 zap_work, details);
754 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800756
757 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758}
759
760#ifdef CONFIG_PREEMPT
761# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
762#else
763/* No preempt: go for improved straight-line efficiency */
764# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
765#endif
766
767/**
768 * unmap_vmas - unmap a range of memory covered by a list of vma's
769 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 * @vma: the starting vma
771 * @start_addr: virtual address at which to start unmapping
772 * @end_addr: virtual address at which to end unmapping
773 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
774 * @details: details of nonlinear truncation or shared cache invalidation
775 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700776 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700777 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700778 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700780 * We aim to not hold locks for too long (for scheduling latency reasons).
781 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782 * return the ending mmu_gather to the caller.
783 *
784 * Only addresses between `start' and `end' will be unmapped.
785 *
786 * The VMA list must be sorted in ascending virtual address order.
787 *
788 * unmap_vmas() assumes that the caller will flush the whole unmapped address
789 * range after unmap_vmas() returns. So the only responsibility here is to
790 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
791 * drops the lock and schedules.
792 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700793unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 struct vm_area_struct *vma, unsigned long start_addr,
795 unsigned long end_addr, unsigned long *nr_accounted,
796 struct zap_details *details)
797{
Robin Holt51c6f662005-11-13 16:06:42 -0800798 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
800 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700801 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700803 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804
805 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806 unsigned long end;
807
808 start = max(vma->vm_start, start_addr);
809 if (start >= vma->vm_end)
810 continue;
811 end = min(vma->vm_end, end_addr);
812 if (end <= vma->vm_start)
813 continue;
814
815 if (vma->vm_flags & VM_ACCOUNT)
816 *nr_accounted += (end - start) >> PAGE_SHIFT;
817
Linus Torvalds1da177e2005-04-16 15:20:36 -0700818 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 if (!tlb_start_valid) {
820 tlb_start = start;
821 tlb_start_valid = 1;
822 }
823
Robin Holt51c6f662005-11-13 16:06:42 -0800824 if (unlikely(is_vm_hugetlb_page(vma))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 unmap_hugepage_range(vma, start, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800826 zap_work -= (end - start) /
827 (HPAGE_SIZE / PAGE_SIZE);
828 start = end;
829 } else
830 start = unmap_page_range(*tlbp, vma,
831 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832
Robin Holt51c6f662005-11-13 16:06:42 -0800833 if (zap_work > 0) {
834 BUG_ON(start != end);
835 break;
836 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837
838 tlb_finish_mmu(*tlbp, tlb_start, start);
839
840 if (need_resched() ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700841 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
842 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700843 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 goto out;
845 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700847 }
848
Hugh Dickins508034a2005-10-29 18:16:30 -0700849 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800851 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 }
853 }
854out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700855 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856}
857
858/**
859 * zap_page_range - remove user pages in a given range
860 * @vma: vm_area_struct holding the applicable pages
861 * @address: starting address of pages to zap
862 * @size: number of bytes to zap
863 * @details: details of nonlinear truncation or shared cache invalidation
864 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700865unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 unsigned long size, struct zap_details *details)
867{
868 struct mm_struct *mm = vma->vm_mm;
869 struct mmu_gather *tlb;
870 unsigned long end = address + size;
871 unsigned long nr_accounted = 0;
872
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700875 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700876 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
877 if (tlb)
878 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700879 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880}
881
882/*
883 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800885struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700886 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887{
888 pgd_t *pgd;
889 pud_t *pud;
890 pmd_t *pmd;
891 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700892 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800894 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700896 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
897 if (!IS_ERR(page)) {
898 BUG_ON(flags & FOLL_GET);
899 goto out;
900 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700902 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 pgd = pgd_offset(mm, address);
904 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700905 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906
907 pud = pud_offset(pgd, address);
908 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700909 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910
911 pmd = pmd_offset(pud, address);
912 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700913 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700915 if (pmd_huge(*pmd)) {
916 BUG_ON(flags & FOLL_GET);
917 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
918 goto out;
919 }
920
921 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 if (!ptep)
923 goto out;
924
925 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700926 if (!pte_present(pte))
927 goto unlock;
928 if ((flags & FOLL_WRITE) && !pte_write(pte))
929 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800930 page = vm_normal_page(vma, address, pte);
931 if (unlikely(!page))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700932 goto unlock;
933
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700934 if (flags & FOLL_GET)
935 get_page(page);
936 if (flags & FOLL_TOUCH) {
937 if ((flags & FOLL_WRITE) &&
938 !pte_dirty(pte) && !PageDirty(page))
939 set_page_dirty(page);
940 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700942unlock:
943 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700944out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700945 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700947no_page_table:
948 /*
949 * When core dumping an enormous anonymous area that nobody
950 * has touched so far, we don't want to allocate page tables.
951 */
952 if (flags & FOLL_ANON) {
953 page = ZERO_PAGE(address);
954 if (flags & FOLL_GET)
955 get_page(page);
956 BUG_ON(flags & FOLL_WRITE);
957 }
958 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959}
960
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
962 unsigned long start, int len, int write, int force,
963 struct page **pages, struct vm_area_struct **vmas)
964{
965 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700966 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967
968 /*
969 * Require read or write permissions.
970 * If 'force' is set, we only require the "MAY" flags.
971 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700972 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
973 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974 i = 0;
975
976 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700977 struct vm_area_struct *vma;
978 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979
980 vma = find_extend_vma(mm, start);
981 if (!vma && in_gate_area(tsk, start)) {
982 unsigned long pg = start & PAGE_MASK;
983 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
984 pgd_t *pgd;
985 pud_t *pud;
986 pmd_t *pmd;
987 pte_t *pte;
988 if (write) /* user gate pages are read-only */
989 return i ? : -EFAULT;
990 if (pg > TASK_SIZE)
991 pgd = pgd_offset_k(pg);
992 else
993 pgd = pgd_offset_gate(mm, pg);
994 BUG_ON(pgd_none(*pgd));
995 pud = pud_offset(pgd, pg);
996 BUG_ON(pud_none(*pud));
997 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700998 if (pmd_none(*pmd))
999 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001001 if (pte_none(*pte)) {
1002 pte_unmap(pte);
1003 return i ? : -EFAULT;
1004 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001005 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001006 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001007 pages[i] = page;
1008 if (page)
1009 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 }
1011 pte_unmap(pte);
1012 if (vmas)
1013 vmas[i] = gate_vma;
1014 i++;
1015 start += PAGE_SIZE;
1016 len--;
1017 continue;
1018 }
1019
Linus Torvalds1ff80382005-12-12 16:24:33 -08001020 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001021 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 return i ? : -EFAULT;
1023
1024 if (is_vm_hugetlb_page(vma)) {
1025 i = follow_hugetlb_page(mm, vma, pages, vmas,
1026 &start, &len, i);
1027 continue;
1028 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001029
1030 foll_flags = FOLL_TOUCH;
1031 if (pages)
1032 foll_flags |= FOLL_GET;
1033 if (!write && !(vma->vm_flags & VM_LOCKED) &&
1034 (!vma->vm_ops || !vma->vm_ops->nopage))
1035 foll_flags |= FOLL_ANON;
1036
Linus Torvalds1da177e2005-04-16 15:20:36 -07001037 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001038 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001040 if (write)
1041 foll_flags |= FOLL_WRITE;
1042
1043 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001044 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001045 int ret;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001046 ret = __handle_mm_fault(mm, vma, start,
1047 foll_flags & FOLL_WRITE);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001048 /*
1049 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1050 * broken COW when necessary, even if maybe_mkwrite
1051 * decided not to set pte_write. We can thus safely do
1052 * subsequent page lookups as if they were reads.
1053 */
1054 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001055 foll_flags &= ~FOLL_WRITE;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001056
1057 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 case VM_FAULT_MINOR:
1059 tsk->min_flt++;
1060 break;
1061 case VM_FAULT_MAJOR:
1062 tsk->maj_flt++;
1063 break;
1064 case VM_FAULT_SIGBUS:
1065 return i ? i : -EFAULT;
1066 case VM_FAULT_OOM:
1067 return i ? i : -ENOMEM;
1068 default:
1069 BUG();
1070 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071 }
1072 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001073 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001074
1075 flush_anon_page(page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001076 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077 }
1078 if (vmas)
1079 vmas[i] = vma;
1080 i++;
1081 start += PAGE_SIZE;
1082 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001083 } while (len && start < vma->vm_end);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001084 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 return i;
1086}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087EXPORT_SYMBOL(get_user_pages);
1088
1089static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1090 unsigned long addr, unsigned long end, pgprot_t prot)
1091{
1092 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001093 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094
Hugh Dickinsc74df322005-10-29 18:16:23 -07001095 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 if (!pte)
1097 return -ENOMEM;
1098 do {
Nick Pigginb5810032005-10-29 18:16:12 -07001099 struct page *page = ZERO_PAGE(addr);
1100 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1101 page_cache_get(page);
1102 page_add_file_rmap(page);
1103 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001104 BUG_ON(!pte_none(*pte));
1105 set_pte_at(mm, addr, pte, zero_pte);
1106 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001107 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108 return 0;
1109}
1110
1111static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1112 unsigned long addr, unsigned long end, pgprot_t prot)
1113{
1114 pmd_t *pmd;
1115 unsigned long next;
1116
1117 pmd = pmd_alloc(mm, pud, addr);
1118 if (!pmd)
1119 return -ENOMEM;
1120 do {
1121 next = pmd_addr_end(addr, end);
1122 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1123 return -ENOMEM;
1124 } while (pmd++, addr = next, addr != end);
1125 return 0;
1126}
1127
1128static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1129 unsigned long addr, unsigned long end, pgprot_t prot)
1130{
1131 pud_t *pud;
1132 unsigned long next;
1133
1134 pud = pud_alloc(mm, pgd, addr);
1135 if (!pud)
1136 return -ENOMEM;
1137 do {
1138 next = pud_addr_end(addr, end);
1139 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1140 return -ENOMEM;
1141 } while (pud++, addr = next, addr != end);
1142 return 0;
1143}
1144
1145int zeromap_page_range(struct vm_area_struct *vma,
1146 unsigned long addr, unsigned long size, pgprot_t prot)
1147{
1148 pgd_t *pgd;
1149 unsigned long next;
1150 unsigned long end = addr + size;
1151 struct mm_struct *mm = vma->vm_mm;
1152 int err;
1153
1154 BUG_ON(addr >= end);
1155 pgd = pgd_offset(mm, addr);
1156 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001157 do {
1158 next = pgd_addr_end(addr, end);
1159 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1160 if (err)
1161 break;
1162 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 return err;
1164}
1165
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001166pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001167{
1168 pgd_t * pgd = pgd_offset(mm, addr);
1169 pud_t * pud = pud_alloc(mm, pgd, addr);
1170 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001171 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001172 if (pmd)
1173 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1174 }
1175 return NULL;
1176}
1177
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001179 * This is the old fallback for page remapping.
1180 *
1181 * For historical reasons, it only allows reserved pages. Only
1182 * old drivers should use this, and they needed to mark their
1183 * pages reserved for the old functions anyway.
1184 */
1185static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
1186{
1187 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001188 pte_t *pte;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001189 spinlock_t *ptl;
1190
1191 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001192 if (PageAnon(page))
Linus Torvalds238f58d2005-11-29 13:01:56 -08001193 goto out;
1194 retval = -ENOMEM;
1195 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001196 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001197 if (!pte)
1198 goto out;
1199 retval = -EBUSY;
1200 if (!pte_none(*pte))
1201 goto out_unlock;
1202
1203 /* Ok, finally just insert the thing.. */
1204 get_page(page);
1205 inc_mm_counter(mm, file_rss);
1206 page_add_file_rmap(page);
1207 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1208
1209 retval = 0;
1210out_unlock:
1211 pte_unmap_unlock(pte, ptl);
1212out:
1213 return retval;
1214}
1215
1216/*
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001217 * This allows drivers to insert individual pages they've allocated
1218 * into a user vma.
1219 *
1220 * The page has to be a nice clean _individual_ kernel allocation.
1221 * If you allocate a compound page, you need to have marked it as
1222 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001223 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001224 *
1225 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1226 * took an arbitrary page protection parameter. This doesn't allow
1227 * that. Your vma protection will have to be set up correctly, which
1228 * means that if you want a shared writable mapping, you'd better
1229 * ask for a shared writable mapping!
1230 *
1231 * The page does not need to be reserved.
1232 */
1233int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1234{
1235 if (addr < vma->vm_start || addr >= vma->vm_end)
1236 return -EFAULT;
1237 if (!page_count(page))
1238 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001239 vma->vm_flags |= VM_INSERTPAGE;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001240 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1241}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001242EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001243
1244/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245 * maps a range of physical memory into the requested pages. the old
1246 * mappings are removed. any references to nonexistent pages results
1247 * in null mappings (currently treated as "copy-on-access")
1248 */
1249static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1250 unsigned long addr, unsigned long end,
1251 unsigned long pfn, pgprot_t prot)
1252{
1253 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001254 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255
Hugh Dickinsc74df322005-10-29 18:16:23 -07001256 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 if (!pte)
1258 return -ENOMEM;
1259 do {
1260 BUG_ON(!pte_none(*pte));
Nick Pigginb5810032005-10-29 18:16:12 -07001261 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 pfn++;
1263 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001264 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 return 0;
1266}
1267
1268static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1269 unsigned long addr, unsigned long end,
1270 unsigned long pfn, pgprot_t prot)
1271{
1272 pmd_t *pmd;
1273 unsigned long next;
1274
1275 pfn -= addr >> PAGE_SHIFT;
1276 pmd = pmd_alloc(mm, pud, addr);
1277 if (!pmd)
1278 return -ENOMEM;
1279 do {
1280 next = pmd_addr_end(addr, end);
1281 if (remap_pte_range(mm, pmd, addr, next,
1282 pfn + (addr >> PAGE_SHIFT), prot))
1283 return -ENOMEM;
1284 } while (pmd++, addr = next, addr != end);
1285 return 0;
1286}
1287
1288static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1289 unsigned long addr, unsigned long end,
1290 unsigned long pfn, pgprot_t prot)
1291{
1292 pud_t *pud;
1293 unsigned long next;
1294
1295 pfn -= addr >> PAGE_SHIFT;
1296 pud = pud_alloc(mm, pgd, addr);
1297 if (!pud)
1298 return -ENOMEM;
1299 do {
1300 next = pud_addr_end(addr, end);
1301 if (remap_pmd_range(mm, pud, addr, next,
1302 pfn + (addr >> PAGE_SHIFT), prot))
1303 return -ENOMEM;
1304 } while (pud++, addr = next, addr != end);
1305 return 0;
1306}
1307
1308/* Note: this is only safe if the mm semaphore is held when called. */
1309int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1310 unsigned long pfn, unsigned long size, pgprot_t prot)
1311{
1312 pgd_t *pgd;
1313 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001314 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001315 struct mm_struct *mm = vma->vm_mm;
1316 int err;
1317
1318 /*
1319 * Physically remapped pages are special. Tell the
1320 * rest of the world about it:
1321 * VM_IO tells people not to look at these pages
1322 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001323 * VM_RESERVED is specified all over the place, because
1324 * in 2.4 it kept swapout's vma scan off this vma; but
1325 * in 2.6 the LRU scan won't even find its pages, so this
1326 * flag means no more than count its pages in reserved_vm,
1327 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001328 * VM_PFNMAP tells the core MM that the base pages are just
1329 * raw PFN mappings, and do not have a "struct page" associated
1330 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001331 *
1332 * There's a horrible special case to handle copy-on-write
1333 * behaviour that some programs depend on. We mark the "original"
1334 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335 */
Linus Torvalds67121172005-12-11 20:38:17 -08001336 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001337 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001338 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001339 vma->vm_pgoff = pfn;
1340 }
1341
Linus Torvalds6aab3412005-11-28 14:34:23 -08001342 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343
1344 BUG_ON(addr >= end);
1345 pfn -= addr >> PAGE_SHIFT;
1346 pgd = pgd_offset(mm, addr);
1347 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 do {
1349 next = pgd_addr_end(addr, end);
1350 err = remap_pud_range(mm, pgd, addr, next,
1351 pfn + (addr >> PAGE_SHIFT), prot);
1352 if (err)
1353 break;
1354 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001355 return err;
1356}
1357EXPORT_SYMBOL(remap_pfn_range);
1358
1359/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001360 * handle_pte_fault chooses page fault handler according to an entry
1361 * which was read non-atomically. Before making any commitment, on
1362 * those architectures or configurations (e.g. i386 with PAE) which
1363 * might give a mix of unmatched parts, do_swap_page and do_file_page
1364 * must check under lock before unmapping the pte and proceeding
1365 * (but do_wp_page is only called after already making such a check;
1366 * and do_anonymous_page and do_no_page can safely check later on).
1367 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001368static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001369 pte_t *page_table, pte_t orig_pte)
1370{
1371 int same = 1;
1372#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1373 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001374 spinlock_t *ptl = pte_lockptr(mm, pmd);
1375 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001376 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001377 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001378 }
1379#endif
1380 pte_unmap(page_table);
1381 return same;
1382}
1383
1384/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001385 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1386 * servicing faults for write access. In the normal case, do always want
1387 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1388 * that do not have writing enabled, when used by access_process_vm.
1389 */
1390static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1391{
1392 if (likely(vma->vm_flags & VM_WRITE))
1393 pte = pte_mkwrite(pte);
1394 return pte;
1395}
1396
Linus Torvalds6aab3412005-11-28 14:34:23 -08001397static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
1398{
1399 /*
1400 * If the source page was a PFN mapping, we don't have
1401 * a "struct page" for it. We do a best-effort copy by
1402 * just copying from the original user address. If that
1403 * fails, we just zero-fill it. Live with it.
1404 */
1405 if (unlikely(!src)) {
1406 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2dbbc2005-11-29 14:07:55 -08001407 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1408
1409 /*
1410 * This really shouldn't fail, because the page is there
1411 * in the page tables. But it might just be unreadable,
1412 * in which case we just give up and fill the result with
1413 * zeroes.
1414 */
1415 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001416 memset(kaddr, 0, PAGE_SIZE);
1417 kunmap_atomic(kaddr, KM_USER0);
1418 return;
1419
1420 }
1421 copy_user_highpage(dst, src, va);
1422}
1423
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001425 * This routine handles present pages, when users try to write
1426 * to a shared page. It is done by copying the page to a new address
1427 * and decrementing the shared-page counter for the old page.
1428 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001429 * Note that this routine assumes that the protection checks have been
1430 * done by the caller (the low-level page fault routine in most cases).
1431 * Thus we can safely just mark it writable once we've done any necessary
1432 * COW.
1433 *
1434 * We also mark the page dirty at this point even though the page will
1435 * change only once the write actually happens. This avoids a few races,
1436 * and potentially makes it more efficient.
1437 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001438 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1439 * but allow concurrent faults), with pte both mapped and locked.
1440 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001442static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1443 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001444 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001446 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 pte_t entry;
Hugh Dickins65500d22005-10-29 18:15:59 -07001448 int ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449
Linus Torvalds6aab3412005-11-28 14:34:23 -08001450 old_page = vm_normal_page(vma, address, orig_pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001451 if (!old_page)
1452 goto gotten;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453
Hugh Dickinsd296e9c2005-06-21 17:15:11 -07001454 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455 int reuse = can_share_swap_page(old_page);
1456 unlock_page(old_page);
1457 if (reuse) {
Ben Collinseca35132005-11-29 11:45:26 -08001458 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001459 entry = pte_mkyoung(orig_pte);
1460 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 ptep_set_access_flags(vma, address, page_table, entry, 1);
1462 update_mmu_cache(vma, address, entry);
1463 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001464 ret |= VM_FAULT_WRITE;
1465 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466 }
1467 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468
1469 /*
1470 * Ok, we need to copy. Oh, well..
1471 */
Nick Pigginb5810032005-10-29 18:16:12 -07001472 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001473gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001474 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475
1476 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001477 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001478 if (old_page == ZERO_PAGE(address)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 new_page = alloc_zeroed_user_highpage(vma, address);
1480 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001481 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001482 } else {
1483 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1484 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001485 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001486 cow_user_page(new_page, old_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001488
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 /*
1490 * Re-check the pte - we dropped the lock
1491 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001492 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001493 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001494 if (old_page) {
1495 page_remove_rmap(old_page);
1496 if (!PageAnon(old_page)) {
1497 dec_mm_counter(mm, file_rss);
1498 inc_mm_counter(mm, anon_rss);
1499 }
1500 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001501 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001502 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001503 entry = mk_pte(new_page, vma->vm_page_prot);
1504 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1505 ptep_establish(vma, address, page_table, entry);
1506 update_mmu_cache(vma, address, entry);
1507 lazy_mmu_prot_update(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08001509 page_add_new_anon_rmap(new_page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510
1511 /* Free the old page.. */
1512 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001513 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001514 }
Hugh Dickins920fc352005-11-21 21:32:17 -08001515 if (new_page)
1516 page_cache_release(new_page);
1517 if (old_page)
1518 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001519unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001520 pte_unmap_unlock(page_table, ptl);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001521 return ret;
Hugh Dickins65500d22005-10-29 18:15:59 -07001522oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001523 if (old_page)
1524 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001525 return VM_FAULT_OOM;
1526}
1527
1528/*
1529 * Helper functions for unmap_mapping_range().
1530 *
1531 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1532 *
1533 * We have to restart searching the prio_tree whenever we drop the lock,
1534 * since the iterator is only valid while the lock is held, and anyway
1535 * a later vma might be split and reinserted earlier while lock dropped.
1536 *
1537 * The list of nonlinear vmas could be handled more efficiently, using
1538 * a placeholder, but handle it in the same way until a need is shown.
1539 * It is important to search the prio_tree before nonlinear list: a vma
1540 * may become nonlinear and be shifted from prio_tree to nonlinear list
1541 * while the lock is dropped; but never shifted from list to prio_tree.
1542 *
1543 * In order to make forward progress despite restarting the search,
1544 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1545 * quickly skip it next time around. Since the prio_tree search only
1546 * shows us those vmas affected by unmapping the range in question, we
1547 * can't efficiently keep all vmas in step with mapping->truncate_count:
1548 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1549 * mapping->truncate_count and vma->vm_truncate_count are protected by
1550 * i_mmap_lock.
1551 *
1552 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001553 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001554 * and restart from that address when we reach that vma again. It might
1555 * have been split or merged, shrunk or extended, but never shifted: so
1556 * restart_addr remains valid so long as it remains in the vma's range.
1557 * unmap_mapping_range forces truncate_count to leap over page-aligned
1558 * values so we can save vma's restart_addr in its truncate_count field.
1559 */
1560#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1561
1562static void reset_vma_truncate_counts(struct address_space *mapping)
1563{
1564 struct vm_area_struct *vma;
1565 struct prio_tree_iter iter;
1566
1567 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1568 vma->vm_truncate_count = 0;
1569 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1570 vma->vm_truncate_count = 0;
1571}
1572
1573static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1574 unsigned long start_addr, unsigned long end_addr,
1575 struct zap_details *details)
1576{
1577 unsigned long restart_addr;
1578 int need_break;
1579
1580again:
1581 restart_addr = vma->vm_truncate_count;
1582 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1583 start_addr = restart_addr;
1584 if (start_addr >= end_addr) {
1585 /* Top of vma has been split off since last time */
1586 vma->vm_truncate_count = details->truncate_count;
1587 return 0;
1588 }
1589 }
1590
Hugh Dickinsee39b372005-04-19 13:29:15 -07001591 restart_addr = zap_page_range(vma, start_addr,
1592 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001593 need_break = need_resched() ||
1594 need_lockbreak(details->i_mmap_lock);
1595
Hugh Dickinsee39b372005-04-19 13:29:15 -07001596 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597 /* We have now completed this vma: mark it so */
1598 vma->vm_truncate_count = details->truncate_count;
1599 if (!need_break)
1600 return 0;
1601 } else {
1602 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001603 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604 if (!need_break)
1605 goto again;
1606 }
1607
1608 spin_unlock(details->i_mmap_lock);
1609 cond_resched();
1610 spin_lock(details->i_mmap_lock);
1611 return -EINTR;
1612}
1613
1614static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1615 struct zap_details *details)
1616{
1617 struct vm_area_struct *vma;
1618 struct prio_tree_iter iter;
1619 pgoff_t vba, vea, zba, zea;
1620
1621restart:
1622 vma_prio_tree_foreach(vma, &iter, root,
1623 details->first_index, details->last_index) {
1624 /* Skip quickly over those we have already dealt with */
1625 if (vma->vm_truncate_count == details->truncate_count)
1626 continue;
1627
1628 vba = vma->vm_pgoff;
1629 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1630 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1631 zba = details->first_index;
1632 if (zba < vba)
1633 zba = vba;
1634 zea = details->last_index;
1635 if (zea > vea)
1636 zea = vea;
1637
1638 if (unmap_mapping_range_vma(vma,
1639 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1640 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1641 details) < 0)
1642 goto restart;
1643 }
1644}
1645
1646static inline void unmap_mapping_range_list(struct list_head *head,
1647 struct zap_details *details)
1648{
1649 struct vm_area_struct *vma;
1650
1651 /*
1652 * In nonlinear VMAs there is no correspondence between virtual address
1653 * offset and file offset. So we must perform an exhaustive search
1654 * across *all* the pages in each nonlinear VMA, not just the pages
1655 * whose virtual address lies outside the file truncation point.
1656 */
1657restart:
1658 list_for_each_entry(vma, head, shared.vm_set.list) {
1659 /* Skip quickly over those we have already dealt with */
1660 if (vma->vm_truncate_count == details->truncate_count)
1661 continue;
1662 details->nonlinear_vma = vma;
1663 if (unmap_mapping_range_vma(vma, vma->vm_start,
1664 vma->vm_end, details) < 0)
1665 goto restart;
1666 }
1667}
1668
1669/**
1670 * unmap_mapping_range - unmap the portion of all mmaps
1671 * in the specified address_space corresponding to the specified
1672 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001673 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001674 * @holebegin: byte in first page to unmap, relative to the start of
1675 * the underlying file. This will be rounded down to a PAGE_SIZE
1676 * boundary. Note that this is different from vmtruncate(), which
1677 * must keep the partial page. In contrast, we must get rid of
1678 * partial pages.
1679 * @holelen: size of prospective hole in bytes. This will be rounded
1680 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1681 * end of the file.
1682 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1683 * but 0 when invalidating pagecache, don't throw away private data.
1684 */
1685void unmap_mapping_range(struct address_space *mapping,
1686 loff_t const holebegin, loff_t const holelen, int even_cows)
1687{
1688 struct zap_details details;
1689 pgoff_t hba = holebegin >> PAGE_SHIFT;
1690 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1691
1692 /* Check for overflow. */
1693 if (sizeof(holelen) > sizeof(hlen)) {
1694 long long holeend =
1695 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1696 if (holeend & ~(long long)ULONG_MAX)
1697 hlen = ULONG_MAX - hba + 1;
1698 }
1699
1700 details.check_mapping = even_cows? NULL: mapping;
1701 details.nonlinear_vma = NULL;
1702 details.first_index = hba;
1703 details.last_index = hba + hlen - 1;
1704 if (details.last_index < details.first_index)
1705 details.last_index = ULONG_MAX;
1706 details.i_mmap_lock = &mapping->i_mmap_lock;
1707
1708 spin_lock(&mapping->i_mmap_lock);
1709
1710 /* serialize i_size write against truncate_count write */
1711 smp_wmb();
1712 /* Protect against page faults, and endless unmapping loops */
1713 mapping->truncate_count++;
1714 /*
1715 * For archs where spin_lock has inclusive semantics like ia64
1716 * this smp_mb() will prevent to read pagetable contents
1717 * before the truncate_count increment is visible to
1718 * other cpus.
1719 */
1720 smp_mb();
1721 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1722 if (mapping->truncate_count == 0)
1723 reset_vma_truncate_counts(mapping);
1724 mapping->truncate_count++;
1725 }
1726 details.truncate_count = mapping->truncate_count;
1727
1728 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1729 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1730 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1731 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1732 spin_unlock(&mapping->i_mmap_lock);
1733}
1734EXPORT_SYMBOL(unmap_mapping_range);
1735
1736/*
1737 * Handle all mappings that got truncated by a "truncate()"
1738 * system call.
1739 *
1740 * NOTE! We have to be ready to update the memory sharing
1741 * between the file and the memory map for a potential last
1742 * incomplete page. Ugly, but necessary.
1743 */
1744int vmtruncate(struct inode * inode, loff_t offset)
1745{
1746 struct address_space *mapping = inode->i_mapping;
1747 unsigned long limit;
1748
1749 if (inode->i_size < offset)
1750 goto do_expand;
1751 /*
1752 * truncation of in-use swapfiles is disallowed - it would cause
1753 * subsequent swapout to scribble on the now-freed blocks.
1754 */
1755 if (IS_SWAPFILE(inode))
1756 goto out_busy;
1757 i_size_write(inode, offset);
1758 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1759 truncate_inode_pages(mapping, offset);
1760 goto out_truncate;
1761
1762do_expand:
1763 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1764 if (limit != RLIM_INFINITY && offset > limit)
1765 goto out_sig;
1766 if (offset > inode->i_sb->s_maxbytes)
1767 goto out_big;
1768 i_size_write(inode, offset);
1769
1770out_truncate:
1771 if (inode->i_op && inode->i_op->truncate)
1772 inode->i_op->truncate(inode);
1773 return 0;
1774out_sig:
1775 send_sig(SIGXFSZ, current, 0);
1776out_big:
1777 return -EFBIG;
1778out_busy:
1779 return -ETXTBSY;
1780}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781EXPORT_SYMBOL(vmtruncate);
1782
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001783int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
1784{
1785 struct address_space *mapping = inode->i_mapping;
1786
1787 /*
1788 * If the underlying filesystem is not going to provide
1789 * a way to truncate a range of blocks (punch a hole) -
1790 * we should return failure right now.
1791 */
1792 if (!inode->i_op || !inode->i_op->truncate_range)
1793 return -ENOSYS;
1794
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001795 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001796 down_write(&inode->i_alloc_sem);
1797 unmap_mapping_range(mapping, offset, (end - offset), 1);
1798 truncate_inode_pages_range(mapping, offset, end);
1799 inode->i_op->truncate_range(inode, offset, end);
1800 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001801 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001802
1803 return 0;
1804}
1805EXPORT_SYMBOL(vmtruncate_range);
1806
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807/*
1808 * Primitive swap readahead code. We simply read an aligned block of
1809 * (1 << page_cluster) entries in the swap area. This method is chosen
1810 * because it doesn't cost us any seek time. We also make sure to queue
1811 * the 'original' request together with the readahead ones...
1812 *
1813 * This has been extended to use the NUMA policies from the mm triggering
1814 * the readahead.
1815 *
1816 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1817 */
1818void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1819{
1820#ifdef CONFIG_NUMA
1821 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1822#endif
1823 int i, num;
1824 struct page *new_page;
1825 unsigned long offset;
1826
1827 /*
1828 * Get the number of handles we should do readahead io to.
1829 */
1830 num = valid_swaphandles(entry, &offset);
1831 for (i = 0; i < num; offset++, i++) {
1832 /* Ok, do the async read-ahead now */
1833 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1834 offset), vma, addr);
1835 if (!new_page)
1836 break;
1837 page_cache_release(new_page);
1838#ifdef CONFIG_NUMA
1839 /*
1840 * Find the next applicable VMA for the NUMA policy.
1841 */
1842 addr += PAGE_SIZE;
1843 if (addr == 0)
1844 vma = NULL;
1845 if (vma) {
1846 if (addr >= vma->vm_end) {
1847 vma = next_vma;
1848 next_vma = vma ? vma->vm_next : NULL;
1849 }
1850 if (vma && addr < vma->vm_start)
1851 vma = NULL;
1852 } else {
1853 if (next_vma && addr >= next_vma->vm_start) {
1854 vma = next_vma;
1855 next_vma = vma->vm_next;
1856 }
1857 }
1858#endif
1859 }
1860 lru_add_drain(); /* Push any new pages onto the LRU now */
1861}
1862
1863/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001864 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1865 * but allow concurrent faults), and pte mapped but not yet locked.
1866 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001868static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1869 unsigned long address, pte_t *page_table, pmd_t *pmd,
1870 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001871{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001872 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001874 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 pte_t pte;
1876 int ret = VM_FAULT_MINOR;
1877
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001878 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001879 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07001880
1881 entry = pte_to_swp_entry(orig_pte);
Christoph Lameterb16664e2006-02-01 03:05:36 -08001882again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001883 page = lookup_swap_cache(entry);
1884 if (!page) {
1885 swapin_readahead(entry, address, vma);
1886 page = read_swap_cache_async(entry, vma, address);
1887 if (!page) {
1888 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001889 * Back out if somebody else faulted in this pte
1890 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001892 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 if (likely(pte_same(*page_table, orig_pte)))
1894 ret = VM_FAULT_OOM;
Hugh Dickins65500d22005-10-29 18:15:59 -07001895 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001896 }
1897
1898 /* Had to read the page from swap area: Major fault */
1899 ret = VM_FAULT_MAJOR;
1900 inc_page_state(pgmajfault);
1901 grab_swap_token();
1902 }
1903
1904 mark_page_accessed(page);
1905 lock_page(page);
Christoph Lameterb16664e2006-02-01 03:05:36 -08001906 if (!PageSwapCache(page)) {
1907 /* Page migration has occured */
1908 unlock_page(page);
1909 page_cache_release(page);
1910 goto again;
1911 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001912
1913 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001914 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001916 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07001917 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07001918 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001919
1920 if (unlikely(!PageUptodate(page))) {
1921 ret = VM_FAULT_SIGBUS;
1922 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923 }
1924
1925 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001926
Hugh Dickins42946212005-10-29 18:16:05 -07001927 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928 pte = mk_pte(page, vma->vm_page_prot);
1929 if (write_access && can_share_swap_page(page)) {
1930 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1931 write_access = 0;
1932 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001933
1934 flush_icache_page(vma, page);
1935 set_pte_at(mm, address, page_table, pte);
1936 page_add_anon_rmap(page, vma, address);
1937
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001938 swap_free(entry);
1939 if (vm_swap_full())
1940 remove_exclusive_swap_page(page);
1941 unlock_page(page);
1942
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943 if (write_access) {
1944 if (do_wp_page(mm, vma, address,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001945 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 ret = VM_FAULT_OOM;
1947 goto out;
1948 }
1949
1950 /* No need to invalidate - it was non-present before */
1951 update_mmu_cache(vma, address, pte);
1952 lazy_mmu_prot_update(pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07001953unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001954 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001955out:
1956 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001957out_nomap:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001958 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07001959 unlock_page(page);
1960 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001961 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962}
1963
1964/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001965 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1966 * but allow concurrent faults), and pte mapped but not yet locked.
1967 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001968 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001969static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1970 unsigned long address, pte_t *page_table, pmd_t *pmd,
1971 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001973 struct page *page;
1974 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001976
Linus Torvalds6aab3412005-11-28 14:34:23 -08001977 if (write_access) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 /* Allocate our own private page. */
1979 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980
1981 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001982 goto oom;
1983 page = alloc_zeroed_user_highpage(vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984 if (!page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001985 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986
Hugh Dickins65500d22005-10-29 18:15:59 -07001987 entry = mk_pte(page, vma->vm_page_prot);
1988 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001989
1990 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1991 if (!pte_none(*page_table))
1992 goto release;
1993 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001994 lru_cache_add_active(page);
Nick Piggin9617d952006-01-06 00:11:12 -08001995 page_add_new_anon_rmap(page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07001996 } else {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001997 /* Map the ZERO_PAGE - vm_page_prot is readonly */
1998 page = ZERO_PAGE(address);
1999 page_cache_get(page);
2000 entry = mk_pte(page, vma->vm_page_prot);
2001
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002002 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002003 spin_lock(ptl);
2004 if (!pte_none(*page_table))
2005 goto release;
Nick Pigginb5810032005-10-29 18:16:12 -07002006 inc_mm_counter(mm, file_rss);
2007 page_add_file_rmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 }
2009
Hugh Dickins65500d22005-10-29 18:15:59 -07002010 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002011
2012 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002013 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002015unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002016 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002017 return VM_FAULT_MINOR;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002018release:
2019 page_cache_release(page);
2020 goto unlock;
Hugh Dickins65500d22005-10-29 18:15:59 -07002021oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022 return VM_FAULT_OOM;
2023}
2024
2025/*
2026 * do_no_page() tries to create a new page mapping. It aggressively
2027 * tries to share with existing pages, but makes a separate copy if
2028 * the "write_access" parameter is true in order to avoid the next
2029 * page fault.
2030 *
2031 * As this is called only for pages that do not currently exist, we
2032 * do not need to flush old virtual caches or the TLB.
2033 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002034 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2035 * but allow concurrent faults), and pte mapped but not yet locked.
2036 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002038static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2039 unsigned long address, pte_t *page_table, pmd_t *pmd,
2040 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002042 spinlock_t *ptl;
Hugh Dickins65500d22005-10-29 18:15:59 -07002043 struct page *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002044 struct address_space *mapping = NULL;
2045 pte_t entry;
2046 unsigned int sequence = 0;
2047 int ret = VM_FAULT_MINOR;
2048 int anon = 0;
2049
Linus Torvalds1da177e2005-04-16 15:20:36 -07002050 pte_unmap(page_table);
Hugh Dickins325f04d2005-11-29 16:55:48 +00002051 BUG_ON(vma->vm_flags & VM_PFNMAP);
2052
Linus Torvalds1da177e2005-04-16 15:20:36 -07002053 if (vma->vm_file) {
2054 mapping = vma->vm_file->f_mapping;
2055 sequence = mapping->truncate_count;
2056 smp_rmb(); /* serializes i_size against truncate_count */
2057 }
2058retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002059 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2060 /*
2061 * No smp_rmb is needed here as long as there's a full
2062 * spin_lock/unlock sequence inside the ->nopage callback
2063 * (for the pagecache lookup) that acts as an implicit
2064 * smp_mb() and prevents the i_size read to happen
2065 * after the next truncate_count read.
2066 */
2067
2068 /* no page was available -- either SIGBUS or OOM */
2069 if (new_page == NOPAGE_SIGBUS)
2070 return VM_FAULT_SIGBUS;
2071 if (new_page == NOPAGE_OOM)
2072 return VM_FAULT_OOM;
2073
2074 /*
2075 * Should we do an early C-O-W break?
2076 */
2077 if (write_access && !(vma->vm_flags & VM_SHARED)) {
2078 struct page *page;
2079
2080 if (unlikely(anon_vma_prepare(vma)))
2081 goto oom;
2082 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
2083 if (!page)
2084 goto oom;
Hugh Dickins325f04d2005-11-29 16:55:48 +00002085 copy_user_highpage(page, new_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002086 page_cache_release(new_page);
2087 new_page = page;
2088 anon = 1;
2089 }
2090
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002091 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002092 /*
2093 * For a file-backed vma, someone could have truncated or otherwise
2094 * invalidated this page. If unmap_mapping_range got called,
2095 * retry getting the page.
2096 */
2097 if (mapping && unlikely(sequence != mapping->truncate_count)) {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002098 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002100 cond_resched();
2101 sequence = mapping->truncate_count;
2102 smp_rmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002103 goto retry;
2104 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002105
2106 /*
2107 * This silly early PAGE_DIRTY setting removes a race
2108 * due to the bad i386 page protection. But it's valid
2109 * for other architectures too.
2110 *
2111 * Note that if write_access is true, we either now have
2112 * an exclusive copy of the page, or this is a shared mapping,
2113 * so we can make it writable and dirty to avoid having to
2114 * handle that later.
2115 */
2116 /* Only go through if we didn't race with anybody else... */
2117 if (pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002118 flush_icache_page(vma, new_page);
2119 entry = mk_pte(new_page, vma->vm_page_prot);
2120 if (write_access)
2121 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2122 set_pte_at(mm, address, page_table, entry);
2123 if (anon) {
Hugh Dickins42946212005-10-29 18:16:05 -07002124 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08002126 page_add_new_anon_rmap(new_page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002127 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002128 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002129 page_add_file_rmap(new_page);
Hugh Dickins42946212005-10-29 18:16:05 -07002130 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002131 } else {
2132 /* One of our sibling threads was faster, back out. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002133 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002134 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 }
2136
2137 /* no need to invalidate: a not-present page shouldn't be cached */
2138 update_mmu_cache(vma, address, entry);
2139 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002140unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002141 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002142 return ret;
2143oom:
2144 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002145 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002146}
2147
2148/*
2149 * Fault of a previously existing named mapping. Repopulate the pte
2150 * from the encoded file_pte if possible. This enables swappable
2151 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002152 *
2153 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2154 * but allow concurrent faults), and pte mapped but not yet locked.
2155 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002157static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
2158 unsigned long address, pte_t *page_table, pmd_t *pmd,
2159 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160{
Hugh Dickins65500d22005-10-29 18:15:59 -07002161 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002162 int err;
2163
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002164 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002165 return VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002166
Hugh Dickins65500d22005-10-29 18:15:59 -07002167 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
2168 /*
2169 * Page table corrupted: show pte and kill process.
2170 */
Nick Pigginb5810032005-10-29 18:16:12 -07002171 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002172 return VM_FAULT_OOM;
2173 }
2174 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2175
2176 pgoff = pte_to_pgoff(orig_pte);
2177 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
2178 vma->vm_page_prot, pgoff, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 if (err == -ENOMEM)
2180 return VM_FAULT_OOM;
2181 if (err)
2182 return VM_FAULT_SIGBUS;
2183 return VM_FAULT_MAJOR;
2184}
2185
2186/*
2187 * These routines also need to handle stuff like marking pages dirty
2188 * and/or accessed for architectures that don't do it in hardware (most
2189 * RISC architectures). The early dirtying is also good on the i386.
2190 *
2191 * There is also a hook called "update_mmu_cache()" that architectures
2192 * with external mmu caches can use to update those (ie the Sparc or
2193 * PowerPC hashed page tables that act as extended TLBs).
2194 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002195 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2196 * but allow concurrent faults), and pte mapped but not yet locked.
2197 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002198 */
2199static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002200 struct vm_area_struct *vma, unsigned long address,
2201 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002202{
2203 pte_t entry;
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002204 pte_t old_entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002205 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002206
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002207 old_entry = entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002208 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002209 if (pte_none(entry)) {
2210 if (!vma->vm_ops || !vma->vm_ops->nopage)
2211 return do_anonymous_page(mm, vma, address,
2212 pte, pmd, write_access);
2213 return do_no_page(mm, vma, address,
2214 pte, pmd, write_access);
2215 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216 if (pte_file(entry))
Hugh Dickins65500d22005-10-29 18:15:59 -07002217 return do_file_page(mm, vma, address,
2218 pte, pmd, write_access, entry);
2219 return do_swap_page(mm, vma, address,
2220 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221 }
2222
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002223 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002224 spin_lock(ptl);
2225 if (unlikely(!pte_same(*pte, entry)))
2226 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002227 if (write_access) {
2228 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002229 return do_wp_page(mm, vma, address,
2230 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 entry = pte_mkdirty(entry);
2232 }
2233 entry = pte_mkyoung(entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002234 if (!pte_same(old_entry, entry)) {
2235 ptep_set_access_flags(vma, address, pte, entry, write_access);
2236 update_mmu_cache(vma, address, entry);
2237 lazy_mmu_prot_update(entry);
2238 } else {
2239 /*
2240 * This is needed only for protection faults but the arch code
2241 * is not yet telling us if this is a protection fault or not.
2242 * This still avoids useless tlb flushes for .text page faults
2243 * with threads.
2244 */
2245 if (write_access)
2246 flush_tlb_page(vma, address);
2247 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002248unlock:
2249 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 return VM_FAULT_MINOR;
2251}
2252
2253/*
2254 * By the time we get here, we already hold the mm semaphore
2255 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002256int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257 unsigned long address, int write_access)
2258{
2259 pgd_t *pgd;
2260 pud_t *pud;
2261 pmd_t *pmd;
2262 pte_t *pte;
2263
2264 __set_current_state(TASK_RUNNING);
2265
2266 inc_page_state(pgfault);
2267
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002268 if (unlikely(is_vm_hugetlb_page(vma)))
2269 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270
Linus Torvalds1da177e2005-04-16 15:20:36 -07002271 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272 pud = pud_alloc(mm, pgd, address);
2273 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002274 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275 pmd = pmd_alloc(mm, pud, address);
2276 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002277 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002278 pte = pte_alloc_map(mm, pmd, address);
2279 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002280 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281
Hugh Dickinsc74df322005-10-29 18:16:23 -07002282 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283}
2284
Arnd Bergmann67207b92005-11-15 15:53:48 -05002285EXPORT_SYMBOL_GPL(__handle_mm_fault);
2286
Linus Torvalds1da177e2005-04-16 15:20:36 -07002287#ifndef __PAGETABLE_PUD_FOLDED
2288/*
2289 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002290 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002291 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002292int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002293{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002294 pud_t *new = pud_alloc_one(mm, address);
2295 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002296 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297
Hugh Dickins872fec12005-10-29 18:16:21 -07002298 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002299 if (pgd_present(*pgd)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300 pud_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002301 else
2302 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002303 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002304 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002305}
Alan Sterne0f39592005-11-28 13:43:44 -08002306#else
2307/* Workaround for gcc 2.96 */
2308int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2309{
2310 return 0;
2311}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002312#endif /* __PAGETABLE_PUD_FOLDED */
2313
2314#ifndef __PAGETABLE_PMD_FOLDED
2315/*
2316 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002317 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002318 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002319int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002321 pmd_t *new = pmd_alloc_one(mm, address);
2322 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002323 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002324
Hugh Dickins872fec12005-10-29 18:16:21 -07002325 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002327 if (pud_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002329 else
2330 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002332 if (pgd_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002334 else
2335 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002337 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002338 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002339}
Alan Sterne0f39592005-11-28 13:43:44 -08002340#else
2341/* Workaround for gcc 2.96 */
2342int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2343{
2344 return 0;
2345}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346#endif /* __PAGETABLE_PMD_FOLDED */
2347
2348int make_pages_present(unsigned long addr, unsigned long end)
2349{
2350 int ret, len, write;
2351 struct vm_area_struct * vma;
2352
2353 vma = find_vma(current->mm, addr);
2354 if (!vma)
2355 return -1;
2356 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02002357 BUG_ON(addr >= end);
2358 BUG_ON(end > vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2360 ret = get_user_pages(current, current->mm, addr,
2361 len, write, 0, NULL, NULL);
2362 if (ret < 0)
2363 return ret;
2364 return ret == len ? 0 : -1;
2365}
2366
2367/*
2368 * Map a vmalloc()-space virtual address to the physical page.
2369 */
2370struct page * vmalloc_to_page(void * vmalloc_addr)
2371{
2372 unsigned long addr = (unsigned long) vmalloc_addr;
2373 struct page *page = NULL;
2374 pgd_t *pgd = pgd_offset_k(addr);
2375 pud_t *pud;
2376 pmd_t *pmd;
2377 pte_t *ptep, pte;
2378
2379 if (!pgd_none(*pgd)) {
2380 pud = pud_offset(pgd, addr);
2381 if (!pud_none(*pud)) {
2382 pmd = pmd_offset(pud, addr);
2383 if (!pmd_none(*pmd)) {
2384 ptep = pte_offset_map(pmd, addr);
2385 pte = *ptep;
2386 if (pte_present(pte))
2387 page = pte_page(pte);
2388 pte_unmap(ptep);
2389 }
2390 }
2391 }
2392 return page;
2393}
2394
2395EXPORT_SYMBOL(vmalloc_to_page);
2396
2397/*
2398 * Map a vmalloc()-space virtual address to the physical page frame number.
2399 */
2400unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2401{
2402 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2403}
2404
2405EXPORT_SYMBOL(vmalloc_to_pfn);
2406
Linus Torvalds1da177e2005-04-16 15:20:36 -07002407#if !defined(__HAVE_ARCH_GATE_AREA)
2408
2409#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002410static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411
2412static int __init gate_vma_init(void)
2413{
2414 gate_vma.vm_mm = NULL;
2415 gate_vma.vm_start = FIXADDR_USER_START;
2416 gate_vma.vm_end = FIXADDR_USER_END;
2417 gate_vma.vm_page_prot = PAGE_READONLY;
Hugh Dickins0b14c172005-11-21 21:32:15 -08002418 gate_vma.vm_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002419 return 0;
2420}
2421__initcall(gate_vma_init);
2422#endif
2423
2424struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2425{
2426#ifdef AT_SYSINFO_EHDR
2427 return &gate_vma;
2428#else
2429 return NULL;
2430#endif
2431}
2432
2433int in_gate_area_no_task(unsigned long addr)
2434{
2435#ifdef AT_SYSINFO_EHDR
2436 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2437 return 1;
2438#endif
2439 return 0;
2440}
2441
2442#endif /* __HAVE_ARCH_GATE_AREA */