blob: 9abc6008544baae37d9d88a4416a4ec81e966132 [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;
90 return 0;
91}
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
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700280 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
281 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
288 && !is_hugepage_only_range(vma->vm_mm, next->vm_start,
289 HPAGE_SIZE)) {
290 vma = next;
291 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700292 anon_vma_unlink(vma);
293 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700294 }
295 free_pgd_range(tlb, addr, vma->vm_end,
296 floor, next? next->vm_start: ceiling);
297 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700298 vma = next;
299 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300}
301
Hugh Dickins1bb36302005-10-29 18:16:22 -0700302int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
Hugh Dickinsc74df322005-10-29 18:16:23 -0700304 struct page *new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700305 if (!new)
306 return -ENOMEM;
307
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700308 pte_lock_init(new);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700309 spin_lock(&mm->page_table_lock);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700310 if (pmd_present(*pmd)) { /* Another has populated it */
311 pte_lock_deinit(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700312 pte_free(new);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700313 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 mm->nr_ptes++;
315 inc_page_state(nr_page_table_pages);
316 pmd_populate(mm, pmd, new);
317 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700318 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700319 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320}
321
Hugh Dickins1bb36302005-10-29 18:16:22 -0700322int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700324 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
325 if (!new)
326 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
Hugh Dickins1bb36302005-10-29 18:16:22 -0700328 spin_lock(&init_mm.page_table_lock);
329 if (pmd_present(*pmd)) /* Another has populated it */
330 pte_free_kernel(new);
331 else
332 pmd_populate_kernel(&init_mm, pmd, new);
333 spin_unlock(&init_mm.page_table_lock);
334 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335}
336
Hugh Dickinsae859762005-10-29 18:16:05 -0700337static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
338{
339 if (file_rss)
340 add_mm_counter(mm, file_rss, file_rss);
341 if (anon_rss)
342 add_mm_counter(mm, anon_rss, anon_rss);
343}
344
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800346 * This function is called to print an error when a bad pte
347 * is found. For example, we might have a PFN-mapped pte in
348 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700349 *
350 * The calling function must still handle the error.
351 */
352void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
353{
354 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
355 "vm_flags = %lx, vaddr = %lx\n",
356 (long long)pte_val(pte),
357 (vma->vm_mm == current->mm ? current->comm : "???"),
358 vma->vm_flags, vaddr);
359 dump_stack();
360}
361
Linus Torvalds67121172005-12-11 20:38:17 -0800362static inline int is_cow_mapping(unsigned int flags)
363{
364 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
365}
366
Nick Pigginb5810032005-10-29 18:16:12 -0700367/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800368 * This function gets the "struct page" associated with a pte.
369 *
370 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
371 * will have each page table entry just pointing to a raw page frame
372 * number, and as far as the VM layer is concerned, those do not have
373 * pages associated with them - even if the PFN might point to memory
374 * that otherwise is perfectly fine and has a "struct page".
375 *
376 * The way we recognize those mappings is through the rules set up
377 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
378 * and the vm_pgoff will point to the first PFN mapped: thus every
379 * page that is a raw mapping will always honor the rule
380 *
381 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
382 *
383 * and if that isn't true, the page has been COW'ed (in which case it
384 * _does_ have a "struct page" associated with it even if it is in a
385 * VM_PFNMAP range).
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800386 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800387struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800388{
Linus Torvalds6aab3412005-11-28 14:34:23 -0800389 unsigned long pfn = pte_pfn(pte);
390
391 if (vma->vm_flags & VM_PFNMAP) {
392 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
393 if (pfn == vma->vm_pgoff + off)
394 return NULL;
Linus Torvalds67121172005-12-11 20:38:17 -0800395 if (!is_cow_mapping(vma->vm_flags))
Linus Torvaldsfb155c12005-12-11 19:46:02 -0800396 return NULL;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800397 }
398
399 /*
400 * Add some anal sanity checks for now. Eventually,
401 * we should just do "return pfn_to_page(pfn)", but
402 * in the meantime we check that we get a valid pfn,
403 * and that the resulting page looks ok.
404 *
405 * Remove this test eventually!
406 */
407 if (unlikely(!pfn_valid(pfn))) {
408 print_bad_pte(vma, pte, addr);
409 return NULL;
410 }
411
412 /*
413 * NOTE! We still have PageReserved() pages in the page
414 * tables.
415 *
416 * The PAGE_ZERO() pages and various VDSO mappings can
417 * cause them to exist.
418 */
419 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800420}
421
422/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 * copy one vm_area from one task to the other. Assumes the page tables
424 * already present in the new task to be cleared in the whole range
425 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426 */
427
Hugh Dickins8c103762005-10-29 18:16:13 -0700428static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700430 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700431 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432{
Nick Pigginb5810032005-10-29 18:16:12 -0700433 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 pte_t pte = *src_pte;
435 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436
437 /* pte contains position in swap or file, so copy. */
438 if (unlikely(!pte_present(pte))) {
439 if (!pte_file(pte)) {
440 swap_duplicate(pte_to_swp_entry(pte));
441 /* make sure dst_mm is on swapoff's mmlist. */
442 if (unlikely(list_empty(&dst_mm->mmlist))) {
443 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700444 if (list_empty(&dst_mm->mmlist))
445 list_add(&dst_mm->mmlist,
446 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 spin_unlock(&mmlist_lock);
448 }
449 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700450 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 }
452
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 /*
454 * If it's a COW mapping, write protect it both
455 * in the parent and the child
456 */
Linus Torvalds67121172005-12-11 20:38:17 -0800457 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 ptep_set_wrprotect(src_mm, addr, src_pte);
459 pte = *src_pte;
460 }
461
462 /*
463 * If it's a shared mapping, mark it clean in
464 * the child
465 */
466 if (vm_flags & VM_SHARED)
467 pte = pte_mkclean(pte);
468 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800469
470 page = vm_normal_page(vma, addr, pte);
471 if (page) {
472 get_page(page);
473 page_dup_rmap(page);
474 rss[!!PageAnon(page)]++;
475 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700476
477out_set_pte:
478 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479}
480
481static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
482 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
483 unsigned long addr, unsigned long end)
484{
485 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700486 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700487 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700488 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489
490again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700491 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700492 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 if (!dst_pte)
494 return -ENOMEM;
495 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700496 src_ptl = pte_lockptr(src_mm, src_pmd);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700497 spin_lock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 do {
500 /*
501 * We are holding two locks at this point - either of them
502 * could generate latencies in another task on another CPU.
503 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700504 if (progress >= 32) {
505 progress = 0;
506 if (need_resched() ||
Hugh Dickinsc74df322005-10-29 18:16:23 -0700507 need_lockbreak(src_ptl) ||
508 need_lockbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700509 break;
510 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 if (pte_none(*src_pte)) {
512 progress++;
513 continue;
514 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700515 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700516 progress += 8;
517 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518
Hugh Dickinsc74df322005-10-29 18:16:23 -0700519 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700521 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700522 pte_unmap_unlock(dst_pte - 1, dst_ptl);
523 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 if (addr != end)
525 goto again;
526 return 0;
527}
528
529static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
530 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
531 unsigned long addr, unsigned long end)
532{
533 pmd_t *src_pmd, *dst_pmd;
534 unsigned long next;
535
536 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
537 if (!dst_pmd)
538 return -ENOMEM;
539 src_pmd = pmd_offset(src_pud, addr);
540 do {
541 next = pmd_addr_end(addr, end);
542 if (pmd_none_or_clear_bad(src_pmd))
543 continue;
544 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
545 vma, addr, next))
546 return -ENOMEM;
547 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
548 return 0;
549}
550
551static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
552 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
553 unsigned long addr, unsigned long end)
554{
555 pud_t *src_pud, *dst_pud;
556 unsigned long next;
557
558 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
559 if (!dst_pud)
560 return -ENOMEM;
561 src_pud = pud_offset(src_pgd, addr);
562 do {
563 next = pud_addr_end(addr, end);
564 if (pud_none_or_clear_bad(src_pud))
565 continue;
566 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
567 vma, addr, next))
568 return -ENOMEM;
569 } while (dst_pud++, src_pud++, addr = next, addr != end);
570 return 0;
571}
572
573int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
574 struct vm_area_struct *vma)
575{
576 pgd_t *src_pgd, *dst_pgd;
577 unsigned long next;
578 unsigned long addr = vma->vm_start;
579 unsigned long end = vma->vm_end;
580
Nick Piggind9928952005-08-28 16:49:11 +1000581 /*
582 * Don't copy ptes where a page fault will fill them correctly.
583 * Fork becomes much lighter when there are big shared or private
584 * readonly mappings. The tradeoff is that copy_page_range is more
585 * efficient than faulting.
586 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800587 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000588 if (!vma->anon_vma)
589 return 0;
590 }
591
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 if (is_vm_hugetlb_page(vma))
593 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
594
595 dst_pgd = pgd_offset(dst_mm, addr);
596 src_pgd = pgd_offset(src_mm, addr);
597 do {
598 next = pgd_addr_end(addr, end);
599 if (pgd_none_or_clear_bad(src_pgd))
600 continue;
601 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
602 vma, addr, next))
603 return -ENOMEM;
604 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
605 return 0;
606}
607
Robin Holt51c6f662005-11-13 16:06:42 -0800608static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700609 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800611 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612{
Nick Pigginb5810032005-10-29 18:16:12 -0700613 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700615 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700616 int file_rss = 0;
617 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618
Hugh Dickins508034a2005-10-29 18:16:30 -0700619 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 do {
621 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800622 if (pte_none(ptent)) {
623 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800625 }
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
629 (*zap_work) -= PAGE_SIZE;
630
Linus Torvalds6aab3412005-11-28 14:34:23 -0800631 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 if (unlikely(details) && page) {
633 /*
634 * unmap_shared_mapping_pages() wants to
635 * invalidate cache without truncating:
636 * unmap shared but keep private pages.
637 */
638 if (details->check_mapping &&
639 details->check_mapping != page->mapping)
640 continue;
641 /*
642 * Each page->index must be checked when
643 * invalidating or truncating nonlinear.
644 */
645 if (details->nonlinear_vma &&
646 (page->index < details->first_index ||
647 page->index > details->last_index))
648 continue;
649 }
Nick Pigginb5810032005-10-29 18:16:12 -0700650 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700651 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 tlb_remove_tlb_entry(tlb, pte, addr);
653 if (unlikely(!page))
654 continue;
655 if (unlikely(details) && details->nonlinear_vma
656 && linear_page_index(details->nonlinear_vma,
657 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700658 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700661 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700662 else {
663 if (pte_dirty(ptent))
664 set_page_dirty(page);
665 if (pte_young(ptent))
666 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700667 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700668 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 page_remove_rmap(page);
670 tlb_remove_page(tlb, page);
671 continue;
672 }
673 /*
674 * If details->check_mapping, we leave swap entries;
675 * if details->nonlinear_vma, we leave file entries.
676 */
677 if (unlikely(details))
678 continue;
679 if (!pte_file(ptent))
680 free_swap_and_cache(pte_to_swp_entry(ptent));
Nick Pigginb5810032005-10-29 18:16:12 -0700681 pte_clear_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800682 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700683
Hugh Dickins86d912f2005-10-29 18:16:14 -0700684 add_mm_rss(mm, file_rss, anon_rss);
Hugh Dickins508034a2005-10-29 18:16:30 -0700685 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800686
687 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688}
689
Robin Holt51c6f662005-11-13 16:06:42 -0800690static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700691 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800693 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694{
695 pmd_t *pmd;
696 unsigned long next;
697
698 pmd = pmd_offset(pud, addr);
699 do {
700 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800701 if (pmd_none_or_clear_bad(pmd)) {
702 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800704 }
705 next = zap_pte_range(tlb, vma, pmd, addr, next,
706 zap_work, details);
707 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
708
709 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700710}
711
Robin Holt51c6f662005-11-13 16:06:42 -0800712static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700713 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800715 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700716{
717 pud_t *pud;
718 unsigned long next;
719
720 pud = pud_offset(pgd, addr);
721 do {
722 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800723 if (pud_none_or_clear_bad(pud)) {
724 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800726 }
727 next = zap_pmd_range(tlb, vma, pud, addr, next,
728 zap_work, details);
729 } while (pud++, addr = next, (addr != end && *zap_work > 0));
730
731 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732}
733
Robin Holt51c6f662005-11-13 16:06:42 -0800734static unsigned long unmap_page_range(struct mmu_gather *tlb,
735 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800737 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738{
739 pgd_t *pgd;
740 unsigned long next;
741
742 if (details && !details->check_mapping && !details->nonlinear_vma)
743 details = NULL;
744
745 BUG_ON(addr >= end);
746 tlb_start_vma(tlb, vma);
747 pgd = pgd_offset(vma->vm_mm, addr);
748 do {
749 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800750 if (pgd_none_or_clear_bad(pgd)) {
751 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800753 }
754 next = zap_pud_range(tlb, vma, pgd, addr, next,
755 zap_work, details);
756 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800758
759 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760}
761
762#ifdef CONFIG_PREEMPT
763# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
764#else
765/* No preempt: go for improved straight-line efficiency */
766# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
767#endif
768
769/**
770 * unmap_vmas - unmap a range of memory covered by a list of vma's
771 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772 * @vma: the starting vma
773 * @start_addr: virtual address at which to start unmapping
774 * @end_addr: virtual address at which to end unmapping
775 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
776 * @details: details of nonlinear truncation or shared cache invalidation
777 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700778 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700780 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700782 * We aim to not hold locks for too long (for scheduling latency reasons).
783 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 * return the ending mmu_gather to the caller.
785 *
786 * Only addresses between `start' and `end' will be unmapped.
787 *
788 * The VMA list must be sorted in ascending virtual address order.
789 *
790 * unmap_vmas() assumes that the caller will flush the whole unmapped address
791 * range after unmap_vmas() returns. So the only responsibility here is to
792 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
793 * drops the lock and schedules.
794 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700795unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 struct vm_area_struct *vma, unsigned long start_addr,
797 unsigned long end_addr, unsigned long *nr_accounted,
798 struct zap_details *details)
799{
Robin Holt51c6f662005-11-13 16:06:42 -0800800 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700801 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
802 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700803 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700804 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700805 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
807 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 unsigned long end;
809
810 start = max(vma->vm_start, start_addr);
811 if (start >= vma->vm_end)
812 continue;
813 end = min(vma->vm_end, end_addr);
814 if (end <= vma->vm_start)
815 continue;
816
817 if (vma->vm_flags & VM_ACCOUNT)
818 *nr_accounted += (end - start) >> PAGE_SHIFT;
819
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 if (!tlb_start_valid) {
822 tlb_start = start;
823 tlb_start_valid = 1;
824 }
825
Robin Holt51c6f662005-11-13 16:06:42 -0800826 if (unlikely(is_vm_hugetlb_page(vma))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 unmap_hugepage_range(vma, start, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800828 zap_work -= (end - start) /
829 (HPAGE_SIZE / PAGE_SIZE);
830 start = end;
831 } else
832 start = unmap_page_range(*tlbp, vma,
833 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834
Robin Holt51c6f662005-11-13 16:06:42 -0800835 if (zap_work > 0) {
836 BUG_ON(start != end);
837 break;
838 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
840 tlb_finish_mmu(*tlbp, tlb_start, start);
841
842 if (need_resched() ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
844 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700845 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 goto out;
847 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 }
850
Hugh Dickins508034a2005-10-29 18:16:30 -0700851 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800853 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 }
855 }
856out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700857 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858}
859
860/**
861 * zap_page_range - remove user pages in a given range
862 * @vma: vm_area_struct holding the applicable pages
863 * @address: starting address of pages to zap
864 * @size: number of bytes to zap
865 * @details: details of nonlinear truncation or shared cache invalidation
866 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700867unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 unsigned long size, struct zap_details *details)
869{
870 struct mm_struct *mm = vma->vm_mm;
871 struct mmu_gather *tlb;
872 unsigned long end = address + size;
873 unsigned long nr_accounted = 0;
874
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700877 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700878 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
879 if (tlb)
880 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700881 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882}
883
884/*
885 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800887struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700888 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700889{
890 pgd_t *pgd;
891 pud_t *pud;
892 pmd_t *pmd;
893 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700894 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800896 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700898 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
899 if (!IS_ERR(page)) {
900 BUG_ON(flags & FOLL_GET);
901 goto out;
902 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700904 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 pgd = pgd_offset(mm, address);
906 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700907 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908
909 pud = pud_offset(pgd, address);
910 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700911 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912
913 pmd = pmd_offset(pud, address);
914 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700915 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700917 if (pmd_huge(*pmd)) {
918 BUG_ON(flags & FOLL_GET);
919 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
920 goto out;
921 }
922
923 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700924 if (!ptep)
925 goto out;
926
927 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700928 if (!pte_present(pte))
929 goto unlock;
930 if ((flags & FOLL_WRITE) && !pte_write(pte))
931 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800932 page = vm_normal_page(vma, address, pte);
933 if (unlikely(!page))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700934 goto unlock;
935
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700936 if (flags & FOLL_GET)
937 get_page(page);
938 if (flags & FOLL_TOUCH) {
939 if ((flags & FOLL_WRITE) &&
940 !pte_dirty(pte) && !PageDirty(page))
941 set_page_dirty(page);
942 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700944unlock:
945 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700947 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700948
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700949no_page_table:
950 /*
951 * When core dumping an enormous anonymous area that nobody
952 * has touched so far, we don't want to allocate page tables.
953 */
954 if (flags & FOLL_ANON) {
955 page = ZERO_PAGE(address);
956 if (flags & FOLL_GET)
957 get_page(page);
958 BUG_ON(flags & FOLL_WRITE);
959 }
960 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961}
962
Linus Torvalds1da177e2005-04-16 15:20:36 -0700963int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
964 unsigned long start, int len, int write, int force,
965 struct page **pages, struct vm_area_struct **vmas)
966{
967 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700968 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700969
970 /*
971 * Require read or write permissions.
972 * If 'force' is set, we only require the "MAY" flags.
973 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700974 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
975 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 i = 0;
977
978 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700979 struct vm_area_struct *vma;
980 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981
982 vma = find_extend_vma(mm, start);
983 if (!vma && in_gate_area(tsk, start)) {
984 unsigned long pg = start & PAGE_MASK;
985 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
986 pgd_t *pgd;
987 pud_t *pud;
988 pmd_t *pmd;
989 pte_t *pte;
990 if (write) /* user gate pages are read-only */
991 return i ? : -EFAULT;
992 if (pg > TASK_SIZE)
993 pgd = pgd_offset_k(pg);
994 else
995 pgd = pgd_offset_gate(mm, pg);
996 BUG_ON(pgd_none(*pgd));
997 pud = pud_offset(pgd, pg);
998 BUG_ON(pud_none(*pud));
999 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001000 if (pmd_none(*pmd))
1001 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001003 if (pte_none(*pte)) {
1004 pte_unmap(pte);
1005 return i ? : -EFAULT;
1006 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001007 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001008 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001009 pages[i] = page;
1010 if (page)
1011 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001012 }
1013 pte_unmap(pte);
1014 if (vmas)
1015 vmas[i] = gate_vma;
1016 i++;
1017 start += PAGE_SIZE;
1018 len--;
1019 continue;
1020 }
1021
Linus Torvalds1ff80382005-12-12 16:24:33 -08001022 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001023 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 return i ? : -EFAULT;
1025
1026 if (is_vm_hugetlb_page(vma)) {
1027 i = follow_hugetlb_page(mm, vma, pages, vmas,
1028 &start, &len, i);
1029 continue;
1030 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001031
1032 foll_flags = FOLL_TOUCH;
1033 if (pages)
1034 foll_flags |= FOLL_GET;
1035 if (!write && !(vma->vm_flags & VM_LOCKED) &&
1036 (!vma->vm_ops || !vma->vm_ops->nopage))
1037 foll_flags |= FOLL_ANON;
1038
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001040 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001042 if (write)
1043 foll_flags |= FOLL_WRITE;
1044
1045 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001046 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001047 int ret;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001048 ret = __handle_mm_fault(mm, vma, start,
1049 foll_flags & FOLL_WRITE);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001050 /*
1051 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1052 * broken COW when necessary, even if maybe_mkwrite
1053 * decided not to set pte_write. We can thus safely do
1054 * subsequent page lookups as if they were reads.
1055 */
1056 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001057 foll_flags &= ~FOLL_WRITE;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001058
1059 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 case VM_FAULT_MINOR:
1061 tsk->min_flt++;
1062 break;
1063 case VM_FAULT_MAJOR:
1064 tsk->maj_flt++;
1065 break;
1066 case VM_FAULT_SIGBUS:
1067 return i ? i : -EFAULT;
1068 case VM_FAULT_OOM:
1069 return i ? i : -ENOMEM;
1070 default:
1071 BUG();
1072 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073 }
1074 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001075 pages[i] = page;
1076 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
1223 * (which is mainly an issue of doing "set_page_count(page, 1)" for
1224 * each sub-page, and then freeing them one by one when you free
1225 * them rather than freeing it as a compound page).
1226 *
1227 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1228 * took an arbitrary page protection parameter. This doesn't allow
1229 * that. Your vma protection will have to be set up correctly, which
1230 * means that if you want a shared writable mapping, you'd better
1231 * ask for a shared writable mapping!
1232 *
1233 * The page does not need to be reserved.
1234 */
1235int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1236{
1237 if (addr < vma->vm_start || addr >= vma->vm_end)
1238 return -EFAULT;
1239 if (!page_count(page))
1240 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001241 vma->vm_flags |= VM_INSERTPAGE;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001242 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1243}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001244EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001245
1246/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 * maps a range of physical memory into the requested pages. the old
1248 * mappings are removed. any references to nonexistent pages results
1249 * in null mappings (currently treated as "copy-on-access")
1250 */
1251static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1252 unsigned long addr, unsigned long end,
1253 unsigned long pfn, pgprot_t prot)
1254{
1255 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001256 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257
Hugh Dickinsc74df322005-10-29 18:16:23 -07001258 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 if (!pte)
1260 return -ENOMEM;
1261 do {
1262 BUG_ON(!pte_none(*pte));
Nick Pigginb5810032005-10-29 18:16:12 -07001263 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001264 pfn++;
1265 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001266 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 return 0;
1268}
1269
1270static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1271 unsigned long addr, unsigned long end,
1272 unsigned long pfn, pgprot_t prot)
1273{
1274 pmd_t *pmd;
1275 unsigned long next;
1276
1277 pfn -= addr >> PAGE_SHIFT;
1278 pmd = pmd_alloc(mm, pud, addr);
1279 if (!pmd)
1280 return -ENOMEM;
1281 do {
1282 next = pmd_addr_end(addr, end);
1283 if (remap_pte_range(mm, pmd, addr, next,
1284 pfn + (addr >> PAGE_SHIFT), prot))
1285 return -ENOMEM;
1286 } while (pmd++, addr = next, addr != end);
1287 return 0;
1288}
1289
1290static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1291 unsigned long addr, unsigned long end,
1292 unsigned long pfn, pgprot_t prot)
1293{
1294 pud_t *pud;
1295 unsigned long next;
1296
1297 pfn -= addr >> PAGE_SHIFT;
1298 pud = pud_alloc(mm, pgd, addr);
1299 if (!pud)
1300 return -ENOMEM;
1301 do {
1302 next = pud_addr_end(addr, end);
1303 if (remap_pmd_range(mm, pud, addr, next,
1304 pfn + (addr >> PAGE_SHIFT), prot))
1305 return -ENOMEM;
1306 } while (pud++, addr = next, addr != end);
1307 return 0;
1308}
1309
1310/* Note: this is only safe if the mm semaphore is held when called. */
1311int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1312 unsigned long pfn, unsigned long size, pgprot_t prot)
1313{
1314 pgd_t *pgd;
1315 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001316 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 struct mm_struct *mm = vma->vm_mm;
1318 int err;
1319
1320 /*
1321 * Physically remapped pages are special. Tell the
1322 * rest of the world about it:
1323 * VM_IO tells people not to look at these pages
1324 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001325 * VM_RESERVED is specified all over the place, because
1326 * in 2.4 it kept swapout's vma scan off this vma; but
1327 * in 2.6 the LRU scan won't even find its pages, so this
1328 * flag means no more than count its pages in reserved_vm,
1329 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001330 * VM_PFNMAP tells the core MM that the base pages are just
1331 * raw PFN mappings, and do not have a "struct page" associated
1332 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001333 *
1334 * There's a horrible special case to handle copy-on-write
1335 * behaviour that some programs depend on. We mark the "original"
1336 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337 */
Linus Torvalds67121172005-12-11 20:38:17 -08001338 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001339 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001340 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001341 vma->vm_pgoff = pfn;
1342 }
1343
Linus Torvalds6aab3412005-11-28 14:34:23 -08001344 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001345
1346 BUG_ON(addr >= end);
1347 pfn -= addr >> PAGE_SHIFT;
1348 pgd = pgd_offset(mm, addr);
1349 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001350 do {
1351 next = pgd_addr_end(addr, end);
1352 err = remap_pud_range(mm, pgd, addr, next,
1353 pfn + (addr >> PAGE_SHIFT), prot);
1354 if (err)
1355 break;
1356 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001357 return err;
1358}
1359EXPORT_SYMBOL(remap_pfn_range);
1360
1361/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001362 * handle_pte_fault chooses page fault handler according to an entry
1363 * which was read non-atomically. Before making any commitment, on
1364 * those architectures or configurations (e.g. i386 with PAE) which
1365 * might give a mix of unmatched parts, do_swap_page and do_file_page
1366 * must check under lock before unmapping the pte and proceeding
1367 * (but do_wp_page is only called after already making such a check;
1368 * and do_anonymous_page and do_no_page can safely check later on).
1369 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001370static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001371 pte_t *page_table, pte_t orig_pte)
1372{
1373 int same = 1;
1374#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1375 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001376 spinlock_t *ptl = pte_lockptr(mm, pmd);
1377 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001378 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001379 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001380 }
1381#endif
1382 pte_unmap(page_table);
1383 return same;
1384}
1385
1386/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001387 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1388 * servicing faults for write access. In the normal case, do always want
1389 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1390 * that do not have writing enabled, when used by access_process_vm.
1391 */
1392static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1393{
1394 if (likely(vma->vm_flags & VM_WRITE))
1395 pte = pte_mkwrite(pte);
1396 return pte;
1397}
1398
Linus Torvalds6aab3412005-11-28 14:34:23 -08001399static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
1400{
1401 /*
1402 * If the source page was a PFN mapping, we don't have
1403 * a "struct page" for it. We do a best-effort copy by
1404 * just copying from the original user address. If that
1405 * fails, we just zero-fill it. Live with it.
1406 */
1407 if (unlikely(!src)) {
1408 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2db2005-11-29 14:07:55 -08001409 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1410
1411 /*
1412 * This really shouldn't fail, because the page is there
1413 * in the page tables. But it might just be unreadable,
1414 * in which case we just give up and fill the result with
1415 * zeroes.
1416 */
1417 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001418 memset(kaddr, 0, PAGE_SIZE);
1419 kunmap_atomic(kaddr, KM_USER0);
1420 return;
1421
1422 }
1423 copy_user_highpage(dst, src, va);
1424}
1425
Linus Torvalds1da177e2005-04-16 15:20:36 -07001426/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427 * This routine handles present pages, when users try to write
1428 * to a shared page. It is done by copying the page to a new address
1429 * and decrementing the shared-page counter for the old page.
1430 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001431 * Note that this routine assumes that the protection checks have been
1432 * done by the caller (the low-level page fault routine in most cases).
1433 * Thus we can safely just mark it writable once we've done any necessary
1434 * COW.
1435 *
1436 * We also mark the page dirty at this point even though the page will
1437 * change only once the write actually happens. This avoids a few races,
1438 * and potentially makes it more efficient.
1439 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001440 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1441 * but allow concurrent faults), with pte both mapped and locked.
1442 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001443 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001444static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1445 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001446 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001448 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001449 pte_t entry;
Hugh Dickins65500d22005-10-29 18:15:59 -07001450 int ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001451
Linus Torvalds6aab3412005-11-28 14:34:23 -08001452 old_page = vm_normal_page(vma, address, orig_pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001453 if (!old_page)
1454 goto gotten;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001455
Hugh Dickinsd296e9c2005-06-21 17:15:11 -07001456 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 int reuse = can_share_swap_page(old_page);
1458 unlock_page(old_page);
1459 if (reuse) {
Ben Collinseca35132005-11-29 11:45:26 -08001460 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001461 entry = pte_mkyoung(orig_pte);
1462 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001463 ptep_set_access_flags(vma, address, page_table, entry, 1);
1464 update_mmu_cache(vma, address, entry);
1465 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001466 ret |= VM_FAULT_WRITE;
1467 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 }
1469 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001470
1471 /*
1472 * Ok, we need to copy. Oh, well..
1473 */
Nick Pigginb5810032005-10-29 18:16:12 -07001474 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001475gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001476 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477
1478 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001479 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001480 if (old_page == ZERO_PAGE(address)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481 new_page = alloc_zeroed_user_highpage(vma, address);
1482 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001483 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 } else {
1485 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1486 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001487 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001488 cow_user_page(new_page, old_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001489 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001490
Linus Torvalds1da177e2005-04-16 15:20:36 -07001491 /*
1492 * Re-check the pte - we dropped the lock
1493 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001494 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001495 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001496 if (old_page) {
1497 page_remove_rmap(old_page);
1498 if (!PageAnon(old_page)) {
1499 dec_mm_counter(mm, file_rss);
1500 inc_mm_counter(mm, anon_rss);
1501 }
1502 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001503 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001504 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001505 entry = mk_pte(new_page, vma->vm_page_prot);
1506 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1507 ptep_establish(vma, address, page_table, entry);
1508 update_mmu_cache(vma, address, entry);
1509 lazy_mmu_prot_update(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08001511 page_add_new_anon_rmap(new_page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512
1513 /* Free the old page.. */
1514 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001515 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516 }
Hugh Dickins920fc352005-11-21 21:32:17 -08001517 if (new_page)
1518 page_cache_release(new_page);
1519 if (old_page)
1520 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001521unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001522 pte_unmap_unlock(page_table, ptl);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001523 return ret;
Hugh Dickins65500d22005-10-29 18:15:59 -07001524oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001525 if (old_page)
1526 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 return VM_FAULT_OOM;
1528}
1529
1530/*
1531 * Helper functions for unmap_mapping_range().
1532 *
1533 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1534 *
1535 * We have to restart searching the prio_tree whenever we drop the lock,
1536 * since the iterator is only valid while the lock is held, and anyway
1537 * a later vma might be split and reinserted earlier while lock dropped.
1538 *
1539 * The list of nonlinear vmas could be handled more efficiently, using
1540 * a placeholder, but handle it in the same way until a need is shown.
1541 * It is important to search the prio_tree before nonlinear list: a vma
1542 * may become nonlinear and be shifted from prio_tree to nonlinear list
1543 * while the lock is dropped; but never shifted from list to prio_tree.
1544 *
1545 * In order to make forward progress despite restarting the search,
1546 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1547 * quickly skip it next time around. Since the prio_tree search only
1548 * shows us those vmas affected by unmapping the range in question, we
1549 * can't efficiently keep all vmas in step with mapping->truncate_count:
1550 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1551 * mapping->truncate_count and vma->vm_truncate_count are protected by
1552 * i_mmap_lock.
1553 *
1554 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001555 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 * and restart from that address when we reach that vma again. It might
1557 * have been split or merged, shrunk or extended, but never shifted: so
1558 * restart_addr remains valid so long as it remains in the vma's range.
1559 * unmap_mapping_range forces truncate_count to leap over page-aligned
1560 * values so we can save vma's restart_addr in its truncate_count field.
1561 */
1562#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1563
1564static void reset_vma_truncate_counts(struct address_space *mapping)
1565{
1566 struct vm_area_struct *vma;
1567 struct prio_tree_iter iter;
1568
1569 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1570 vma->vm_truncate_count = 0;
1571 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1572 vma->vm_truncate_count = 0;
1573}
1574
1575static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1576 unsigned long start_addr, unsigned long end_addr,
1577 struct zap_details *details)
1578{
1579 unsigned long restart_addr;
1580 int need_break;
1581
1582again:
1583 restart_addr = vma->vm_truncate_count;
1584 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1585 start_addr = restart_addr;
1586 if (start_addr >= end_addr) {
1587 /* Top of vma has been split off since last time */
1588 vma->vm_truncate_count = details->truncate_count;
1589 return 0;
1590 }
1591 }
1592
Hugh Dickinsee39b372005-04-19 13:29:15 -07001593 restart_addr = zap_page_range(vma, start_addr,
1594 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595 need_break = need_resched() ||
1596 need_lockbreak(details->i_mmap_lock);
1597
Hugh Dickinsee39b372005-04-19 13:29:15 -07001598 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001599 /* We have now completed this vma: mark it so */
1600 vma->vm_truncate_count = details->truncate_count;
1601 if (!need_break)
1602 return 0;
1603 } else {
1604 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001605 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 if (!need_break)
1607 goto again;
1608 }
1609
1610 spin_unlock(details->i_mmap_lock);
1611 cond_resched();
1612 spin_lock(details->i_mmap_lock);
1613 return -EINTR;
1614}
1615
1616static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1617 struct zap_details *details)
1618{
1619 struct vm_area_struct *vma;
1620 struct prio_tree_iter iter;
1621 pgoff_t vba, vea, zba, zea;
1622
1623restart:
1624 vma_prio_tree_foreach(vma, &iter, root,
1625 details->first_index, details->last_index) {
1626 /* Skip quickly over those we have already dealt with */
1627 if (vma->vm_truncate_count == details->truncate_count)
1628 continue;
1629
1630 vba = vma->vm_pgoff;
1631 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1632 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1633 zba = details->first_index;
1634 if (zba < vba)
1635 zba = vba;
1636 zea = details->last_index;
1637 if (zea > vea)
1638 zea = vea;
1639
1640 if (unmap_mapping_range_vma(vma,
1641 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1642 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1643 details) < 0)
1644 goto restart;
1645 }
1646}
1647
1648static inline void unmap_mapping_range_list(struct list_head *head,
1649 struct zap_details *details)
1650{
1651 struct vm_area_struct *vma;
1652
1653 /*
1654 * In nonlinear VMAs there is no correspondence between virtual address
1655 * offset and file offset. So we must perform an exhaustive search
1656 * across *all* the pages in each nonlinear VMA, not just the pages
1657 * whose virtual address lies outside the file truncation point.
1658 */
1659restart:
1660 list_for_each_entry(vma, head, shared.vm_set.list) {
1661 /* Skip quickly over those we have already dealt with */
1662 if (vma->vm_truncate_count == details->truncate_count)
1663 continue;
1664 details->nonlinear_vma = vma;
1665 if (unmap_mapping_range_vma(vma, vma->vm_start,
1666 vma->vm_end, details) < 0)
1667 goto restart;
1668 }
1669}
1670
1671/**
1672 * unmap_mapping_range - unmap the portion of all mmaps
1673 * in the specified address_space corresponding to the specified
1674 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001675 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001676 * @holebegin: byte in first page to unmap, relative to the start of
1677 * the underlying file. This will be rounded down to a PAGE_SIZE
1678 * boundary. Note that this is different from vmtruncate(), which
1679 * must keep the partial page. In contrast, we must get rid of
1680 * partial pages.
1681 * @holelen: size of prospective hole in bytes. This will be rounded
1682 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1683 * end of the file.
1684 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1685 * but 0 when invalidating pagecache, don't throw away private data.
1686 */
1687void unmap_mapping_range(struct address_space *mapping,
1688 loff_t const holebegin, loff_t const holelen, int even_cows)
1689{
1690 struct zap_details details;
1691 pgoff_t hba = holebegin >> PAGE_SHIFT;
1692 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1693
1694 /* Check for overflow. */
1695 if (sizeof(holelen) > sizeof(hlen)) {
1696 long long holeend =
1697 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1698 if (holeend & ~(long long)ULONG_MAX)
1699 hlen = ULONG_MAX - hba + 1;
1700 }
1701
1702 details.check_mapping = even_cows? NULL: mapping;
1703 details.nonlinear_vma = NULL;
1704 details.first_index = hba;
1705 details.last_index = hba + hlen - 1;
1706 if (details.last_index < details.first_index)
1707 details.last_index = ULONG_MAX;
1708 details.i_mmap_lock = &mapping->i_mmap_lock;
1709
1710 spin_lock(&mapping->i_mmap_lock);
1711
1712 /* serialize i_size write against truncate_count write */
1713 smp_wmb();
1714 /* Protect against page faults, and endless unmapping loops */
1715 mapping->truncate_count++;
1716 /*
1717 * For archs where spin_lock has inclusive semantics like ia64
1718 * this smp_mb() will prevent to read pagetable contents
1719 * before the truncate_count increment is visible to
1720 * other cpus.
1721 */
1722 smp_mb();
1723 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1724 if (mapping->truncate_count == 0)
1725 reset_vma_truncate_counts(mapping);
1726 mapping->truncate_count++;
1727 }
1728 details.truncate_count = mapping->truncate_count;
1729
1730 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1731 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1732 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1733 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1734 spin_unlock(&mapping->i_mmap_lock);
1735}
1736EXPORT_SYMBOL(unmap_mapping_range);
1737
1738/*
1739 * Handle all mappings that got truncated by a "truncate()"
1740 * system call.
1741 *
1742 * NOTE! We have to be ready to update the memory sharing
1743 * between the file and the memory map for a potential last
1744 * incomplete page. Ugly, but necessary.
1745 */
1746int vmtruncate(struct inode * inode, loff_t offset)
1747{
1748 struct address_space *mapping = inode->i_mapping;
1749 unsigned long limit;
1750
1751 if (inode->i_size < offset)
1752 goto do_expand;
1753 /*
1754 * truncation of in-use swapfiles is disallowed - it would cause
1755 * subsequent swapout to scribble on the now-freed blocks.
1756 */
1757 if (IS_SWAPFILE(inode))
1758 goto out_busy;
1759 i_size_write(inode, offset);
1760 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1761 truncate_inode_pages(mapping, offset);
1762 goto out_truncate;
1763
1764do_expand:
1765 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1766 if (limit != RLIM_INFINITY && offset > limit)
1767 goto out_sig;
1768 if (offset > inode->i_sb->s_maxbytes)
1769 goto out_big;
1770 i_size_write(inode, offset);
1771
1772out_truncate:
1773 if (inode->i_op && inode->i_op->truncate)
1774 inode->i_op->truncate(inode);
1775 return 0;
1776out_sig:
1777 send_sig(SIGXFSZ, current, 0);
1778out_big:
1779 return -EFBIG;
1780out_busy:
1781 return -ETXTBSY;
1782}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783EXPORT_SYMBOL(vmtruncate);
1784
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001785int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
1786{
1787 struct address_space *mapping = inode->i_mapping;
1788
1789 /*
1790 * If the underlying filesystem is not going to provide
1791 * a way to truncate a range of blocks (punch a hole) -
1792 * we should return failure right now.
1793 */
1794 if (!inode->i_op || !inode->i_op->truncate_range)
1795 return -ENOSYS;
1796
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001797 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001798 down_write(&inode->i_alloc_sem);
1799 unmap_mapping_range(mapping, offset, (end - offset), 1);
1800 truncate_inode_pages_range(mapping, offset, end);
1801 inode->i_op->truncate_range(inode, offset, end);
1802 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001803 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001804
1805 return 0;
1806}
1807EXPORT_SYMBOL(vmtruncate_range);
1808
Linus Torvalds1da177e2005-04-16 15:20:36 -07001809/*
1810 * Primitive swap readahead code. We simply read an aligned block of
1811 * (1 << page_cluster) entries in the swap area. This method is chosen
1812 * because it doesn't cost us any seek time. We also make sure to queue
1813 * the 'original' request together with the readahead ones...
1814 *
1815 * This has been extended to use the NUMA policies from the mm triggering
1816 * the readahead.
1817 *
1818 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1819 */
1820void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1821{
1822#ifdef CONFIG_NUMA
1823 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1824#endif
1825 int i, num;
1826 struct page *new_page;
1827 unsigned long offset;
1828
1829 /*
1830 * Get the number of handles we should do readahead io to.
1831 */
1832 num = valid_swaphandles(entry, &offset);
1833 for (i = 0; i < num; offset++, i++) {
1834 /* Ok, do the async read-ahead now */
1835 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1836 offset), vma, addr);
1837 if (!new_page)
1838 break;
1839 page_cache_release(new_page);
1840#ifdef CONFIG_NUMA
1841 /*
1842 * Find the next applicable VMA for the NUMA policy.
1843 */
1844 addr += PAGE_SIZE;
1845 if (addr == 0)
1846 vma = NULL;
1847 if (vma) {
1848 if (addr >= vma->vm_end) {
1849 vma = next_vma;
1850 next_vma = vma ? vma->vm_next : NULL;
1851 }
1852 if (vma && addr < vma->vm_start)
1853 vma = NULL;
1854 } else {
1855 if (next_vma && addr >= next_vma->vm_start) {
1856 vma = next_vma;
1857 next_vma = vma->vm_next;
1858 }
1859 }
1860#endif
1861 }
1862 lru_add_drain(); /* Push any new pages onto the LRU now */
1863}
1864
1865/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001866 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1867 * but allow concurrent faults), and pte mapped but not yet locked.
1868 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001869 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001870static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1871 unsigned long address, pte_t *page_table, pmd_t *pmd,
1872 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001874 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001876 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 pte_t pte;
1878 int ret = VM_FAULT_MINOR;
1879
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001880 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001881 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07001882
1883 entry = pte_to_swp_entry(orig_pte);
Christoph Lameterb16664e2006-02-01 03:05:36 -08001884again:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 page = lookup_swap_cache(entry);
1886 if (!page) {
1887 swapin_readahead(entry, address, vma);
1888 page = read_swap_cache_async(entry, vma, address);
1889 if (!page) {
1890 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001891 * Back out if somebody else faulted in this pte
1892 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001894 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895 if (likely(pte_same(*page_table, orig_pte)))
1896 ret = VM_FAULT_OOM;
Hugh Dickins65500d22005-10-29 18:15:59 -07001897 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 }
1899
1900 /* Had to read the page from swap area: Major fault */
1901 ret = VM_FAULT_MAJOR;
1902 inc_page_state(pgmajfault);
1903 grab_swap_token();
1904 }
1905
1906 mark_page_accessed(page);
1907 lock_page(page);
Christoph Lameterb16664e2006-02-01 03:05:36 -08001908 if (!PageSwapCache(page)) {
1909 /* Page migration has occured */
1910 unlock_page(page);
1911 page_cache_release(page);
1912 goto again;
1913 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001914
1915 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001916 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001918 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07001919 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07001920 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001921
1922 if (unlikely(!PageUptodate(page))) {
1923 ret = VM_FAULT_SIGBUS;
1924 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925 }
1926
1927 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001928
Hugh Dickins42946212005-10-29 18:16:05 -07001929 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 pte = mk_pte(page, vma->vm_page_prot);
1931 if (write_access && can_share_swap_page(page)) {
1932 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1933 write_access = 0;
1934 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001935
1936 flush_icache_page(vma, page);
1937 set_pte_at(mm, address, page_table, pte);
1938 page_add_anon_rmap(page, vma, address);
1939
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001940 swap_free(entry);
1941 if (vm_swap_full())
1942 remove_exclusive_swap_page(page);
1943 unlock_page(page);
1944
Linus Torvalds1da177e2005-04-16 15:20:36 -07001945 if (write_access) {
1946 if (do_wp_page(mm, vma, address,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001947 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948 ret = VM_FAULT_OOM;
1949 goto out;
1950 }
1951
1952 /* No need to invalidate - it was non-present before */
1953 update_mmu_cache(vma, address, pte);
1954 lazy_mmu_prot_update(pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07001955unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001956 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001957out:
1958 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001959out_nomap:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001960 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07001961 unlock_page(page);
1962 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001963 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001964}
1965
1966/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001967 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1968 * but allow concurrent faults), and pte mapped but not yet locked.
1969 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001970 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001971static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1972 unsigned long address, pte_t *page_table, pmd_t *pmd,
1973 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001975 struct page *page;
1976 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978
Linus Torvalds6aab3412005-11-28 14:34:23 -08001979 if (write_access) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 /* Allocate our own private page. */
1981 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001982
1983 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001984 goto oom;
1985 page = alloc_zeroed_user_highpage(vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 if (!page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001987 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001988
Hugh Dickins65500d22005-10-29 18:15:59 -07001989 entry = mk_pte(page, vma->vm_page_prot);
1990 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001991
1992 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1993 if (!pte_none(*page_table))
1994 goto release;
1995 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996 lru_cache_add_active(page);
Nick Piggin9617d952006-01-06 00:11:12 -08001997 page_add_new_anon_rmap(page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07001998 } else {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001999 /* Map the ZERO_PAGE - vm_page_prot is readonly */
2000 page = ZERO_PAGE(address);
2001 page_cache_get(page);
2002 entry = mk_pte(page, vma->vm_page_prot);
2003
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002004 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002005 spin_lock(ptl);
2006 if (!pte_none(*page_table))
2007 goto release;
Nick Pigginb5810032005-10-29 18:16:12 -07002008 inc_mm_counter(mm, file_rss);
2009 page_add_file_rmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002010 }
2011
Hugh Dickins65500d22005-10-29 18:15:59 -07002012 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013
2014 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002015 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002016 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002017unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002018 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002019 return VM_FAULT_MINOR;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002020release:
2021 page_cache_release(page);
2022 goto unlock;
Hugh Dickins65500d22005-10-29 18:15:59 -07002023oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024 return VM_FAULT_OOM;
2025}
2026
2027/*
2028 * do_no_page() tries to create a new page mapping. It aggressively
2029 * tries to share with existing pages, but makes a separate copy if
2030 * the "write_access" parameter is true in order to avoid the next
2031 * page fault.
2032 *
2033 * As this is called only for pages that do not currently exist, we
2034 * do not need to flush old virtual caches or the TLB.
2035 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002036 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2037 * but allow concurrent faults), and pte mapped but not yet locked.
2038 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002039 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002040static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2041 unsigned long address, pte_t *page_table, pmd_t *pmd,
2042 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002044 spinlock_t *ptl;
Hugh Dickins65500d22005-10-29 18:15:59 -07002045 struct page *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 struct address_space *mapping = NULL;
2047 pte_t entry;
2048 unsigned int sequence = 0;
2049 int ret = VM_FAULT_MINOR;
2050 int anon = 0;
2051
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052 pte_unmap(page_table);
Hugh Dickins325f04d2005-11-29 16:55:48 +00002053 BUG_ON(vma->vm_flags & VM_PFNMAP);
2054
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 if (vma->vm_file) {
2056 mapping = vma->vm_file->f_mapping;
2057 sequence = mapping->truncate_count;
2058 smp_rmb(); /* serializes i_size against truncate_count */
2059 }
2060retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2062 /*
2063 * No smp_rmb is needed here as long as there's a full
2064 * spin_lock/unlock sequence inside the ->nopage callback
2065 * (for the pagecache lookup) that acts as an implicit
2066 * smp_mb() and prevents the i_size read to happen
2067 * after the next truncate_count read.
2068 */
2069
2070 /* no page was available -- either SIGBUS or OOM */
2071 if (new_page == NOPAGE_SIGBUS)
2072 return VM_FAULT_SIGBUS;
2073 if (new_page == NOPAGE_OOM)
2074 return VM_FAULT_OOM;
2075
2076 /*
2077 * Should we do an early C-O-W break?
2078 */
2079 if (write_access && !(vma->vm_flags & VM_SHARED)) {
2080 struct page *page;
2081
2082 if (unlikely(anon_vma_prepare(vma)))
2083 goto oom;
2084 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
2085 if (!page)
2086 goto oom;
Hugh Dickins325f04d2005-11-29 16:55:48 +00002087 copy_user_highpage(page, new_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002088 page_cache_release(new_page);
2089 new_page = page;
2090 anon = 1;
2091 }
2092
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002093 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002094 /*
2095 * For a file-backed vma, someone could have truncated or otherwise
2096 * invalidated this page. If unmap_mapping_range got called,
2097 * retry getting the page.
2098 */
2099 if (mapping && unlikely(sequence != mapping->truncate_count)) {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002100 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002102 cond_resched();
2103 sequence = mapping->truncate_count;
2104 smp_rmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002105 goto retry;
2106 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107
2108 /*
2109 * This silly early PAGE_DIRTY setting removes a race
2110 * due to the bad i386 page protection. But it's valid
2111 * for other architectures too.
2112 *
2113 * Note that if write_access is true, we either now have
2114 * an exclusive copy of the page, or this is a shared mapping,
2115 * so we can make it writable and dirty to avoid having to
2116 * handle that later.
2117 */
2118 /* Only go through if we didn't race with anybody else... */
2119 if (pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002120 flush_icache_page(vma, new_page);
2121 entry = mk_pte(new_page, vma->vm_page_prot);
2122 if (write_access)
2123 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2124 set_pte_at(mm, address, page_table, entry);
2125 if (anon) {
Hugh Dickins42946212005-10-29 18:16:05 -07002126 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002127 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08002128 page_add_new_anon_rmap(new_page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002129 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002130 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002131 page_add_file_rmap(new_page);
Hugh Dickins42946212005-10-29 18:16:05 -07002132 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002133 } else {
2134 /* One of our sibling threads was faster, back out. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002135 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002136 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002137 }
2138
2139 /* no need to invalidate: a not-present page shouldn't be cached */
2140 update_mmu_cache(vma, address, entry);
2141 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002142unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002143 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002144 return ret;
2145oom:
2146 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002147 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148}
2149
2150/*
2151 * Fault of a previously existing named mapping. Repopulate the pte
2152 * from the encoded file_pte if possible. This enables swappable
2153 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002154 *
2155 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2156 * but allow concurrent faults), and pte mapped but not yet locked.
2157 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002159static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
2160 unsigned long address, pte_t *page_table, pmd_t *pmd,
2161 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002162{
Hugh Dickins65500d22005-10-29 18:15:59 -07002163 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164 int err;
2165
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002166 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002167 return VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168
Hugh Dickins65500d22005-10-29 18:15:59 -07002169 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
2170 /*
2171 * Page table corrupted: show pte and kill process.
2172 */
Nick Pigginb5810032005-10-29 18:16:12 -07002173 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002174 return VM_FAULT_OOM;
2175 }
2176 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2177
2178 pgoff = pte_to_pgoff(orig_pte);
2179 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
2180 vma->vm_page_prot, pgoff, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002181 if (err == -ENOMEM)
2182 return VM_FAULT_OOM;
2183 if (err)
2184 return VM_FAULT_SIGBUS;
2185 return VM_FAULT_MAJOR;
2186}
2187
2188/*
2189 * These routines also need to handle stuff like marking pages dirty
2190 * and/or accessed for architectures that don't do it in hardware (most
2191 * RISC architectures). The early dirtying is also good on the i386.
2192 *
2193 * There is also a hook called "update_mmu_cache()" that architectures
2194 * with external mmu caches can use to update those (ie the Sparc or
2195 * PowerPC hashed page tables that act as extended TLBs).
2196 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002197 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2198 * but allow concurrent faults), and pte mapped but not yet locked.
2199 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002200 */
2201static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002202 struct vm_area_struct *vma, unsigned long address,
2203 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002204{
2205 pte_t entry;
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002206 pte_t old_entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002207 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002208
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002209 old_entry = entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002211 if (pte_none(entry)) {
2212 if (!vma->vm_ops || !vma->vm_ops->nopage)
2213 return do_anonymous_page(mm, vma, address,
2214 pte, pmd, write_access);
2215 return do_no_page(mm, vma, address,
2216 pte, pmd, write_access);
2217 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002218 if (pte_file(entry))
Hugh Dickins65500d22005-10-29 18:15:59 -07002219 return do_file_page(mm, vma, address,
2220 pte, pmd, write_access, entry);
2221 return do_swap_page(mm, vma, address,
2222 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223 }
2224
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002225 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002226 spin_lock(ptl);
2227 if (unlikely(!pte_same(*pte, entry)))
2228 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002229 if (write_access) {
2230 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002231 return do_wp_page(mm, vma, address,
2232 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002233 entry = pte_mkdirty(entry);
2234 }
2235 entry = pte_mkyoung(entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002236 if (!pte_same(old_entry, entry)) {
2237 ptep_set_access_flags(vma, address, pte, entry, write_access);
2238 update_mmu_cache(vma, address, entry);
2239 lazy_mmu_prot_update(entry);
2240 } else {
2241 /*
2242 * This is needed only for protection faults but the arch code
2243 * is not yet telling us if this is a protection fault or not.
2244 * This still avoids useless tlb flushes for .text page faults
2245 * with threads.
2246 */
2247 if (write_access)
2248 flush_tlb_page(vma, address);
2249 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002250unlock:
2251 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252 return VM_FAULT_MINOR;
2253}
2254
2255/*
2256 * By the time we get here, we already hold the mm semaphore
2257 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002258int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002259 unsigned long address, int write_access)
2260{
2261 pgd_t *pgd;
2262 pud_t *pud;
2263 pmd_t *pmd;
2264 pte_t *pte;
2265
2266 __set_current_state(TASK_RUNNING);
2267
2268 inc_page_state(pgfault);
2269
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002270 if (unlikely(is_vm_hugetlb_page(vma)))
2271 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002272
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002274 pud = pud_alloc(mm, pgd, address);
2275 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002276 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002277 pmd = pmd_alloc(mm, pud, address);
2278 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002279 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 pte = pte_alloc_map(mm, pmd, address);
2281 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002282 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283
Hugh Dickinsc74df322005-10-29 18:16:23 -07002284 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002285}
2286
Arnd Bergmann67207b92005-11-15 15:53:48 -05002287EXPORT_SYMBOL_GPL(__handle_mm_fault);
2288
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289#ifndef __PAGETABLE_PUD_FOLDED
2290/*
2291 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002292 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002293 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002294int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002295{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002296 pud_t *new = pud_alloc_one(mm, address);
2297 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002298 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002299
Hugh Dickins872fec12005-10-29 18:16:21 -07002300 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002301 if (pgd_present(*pgd)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302 pud_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002303 else
2304 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002305 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002306 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002307}
Alan Sterne0f39592005-11-28 13:43:44 -08002308#else
2309/* Workaround for gcc 2.96 */
2310int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2311{
2312 return 0;
2313}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314#endif /* __PAGETABLE_PUD_FOLDED */
2315
2316#ifndef __PAGETABLE_PMD_FOLDED
2317/*
2318 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002319 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002321int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002323 pmd_t *new = pmd_alloc_one(mm, address);
2324 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002325 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326
Hugh Dickins872fec12005-10-29 18:16:21 -07002327 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002328#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002329 if (pud_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002330 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002331 else
2332 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002333#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002334 if (pgd_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002335 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002336 else
2337 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002338#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002339 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002340 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341}
Alan Sterne0f39592005-11-28 13:43:44 -08002342#else
2343/* Workaround for gcc 2.96 */
2344int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2345{
2346 return 0;
2347}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348#endif /* __PAGETABLE_PMD_FOLDED */
2349
2350int make_pages_present(unsigned long addr, unsigned long end)
2351{
2352 int ret, len, write;
2353 struct vm_area_struct * vma;
2354
2355 vma = find_vma(current->mm, addr);
2356 if (!vma)
2357 return -1;
2358 write = (vma->vm_flags & VM_WRITE) != 0;
2359 if (addr >= end)
2360 BUG();
2361 if (end > vma->vm_end)
2362 BUG();
2363 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2364 ret = get_user_pages(current, current->mm, addr,
2365 len, write, 0, NULL, NULL);
2366 if (ret < 0)
2367 return ret;
2368 return ret == len ? 0 : -1;
2369}
2370
2371/*
2372 * Map a vmalloc()-space virtual address to the physical page.
2373 */
2374struct page * vmalloc_to_page(void * vmalloc_addr)
2375{
2376 unsigned long addr = (unsigned long) vmalloc_addr;
2377 struct page *page = NULL;
2378 pgd_t *pgd = pgd_offset_k(addr);
2379 pud_t *pud;
2380 pmd_t *pmd;
2381 pte_t *ptep, pte;
2382
2383 if (!pgd_none(*pgd)) {
2384 pud = pud_offset(pgd, addr);
2385 if (!pud_none(*pud)) {
2386 pmd = pmd_offset(pud, addr);
2387 if (!pmd_none(*pmd)) {
2388 ptep = pte_offset_map(pmd, addr);
2389 pte = *ptep;
2390 if (pte_present(pte))
2391 page = pte_page(pte);
2392 pte_unmap(ptep);
2393 }
2394 }
2395 }
2396 return page;
2397}
2398
2399EXPORT_SYMBOL(vmalloc_to_page);
2400
2401/*
2402 * Map a vmalloc()-space virtual address to the physical page frame number.
2403 */
2404unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2405{
2406 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2407}
2408
2409EXPORT_SYMBOL(vmalloc_to_pfn);
2410
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411#if !defined(__HAVE_ARCH_GATE_AREA)
2412
2413#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002414static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002415
2416static int __init gate_vma_init(void)
2417{
2418 gate_vma.vm_mm = NULL;
2419 gate_vma.vm_start = FIXADDR_USER_START;
2420 gate_vma.vm_end = FIXADDR_USER_END;
2421 gate_vma.vm_page_prot = PAGE_READONLY;
Hugh Dickins0b14c172005-11-21 21:32:15 -08002422 gate_vma.vm_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002423 return 0;
2424}
2425__initcall(gate_vma_init);
2426#endif
2427
2428struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2429{
2430#ifdef AT_SYSINFO_EHDR
2431 return &gate_vma;
2432#else
2433 return NULL;
2434#endif
2435}
2436
2437int in_gate_area_no_task(unsigned long addr)
2438{
2439#ifdef AT_SYSINFO_EHDR
2440 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2441 return 1;
2442#endif
2443 return 0;
2444}
2445
2446#endif /* __HAVE_ARCH_GATE_AREA */