blob: aed45eaf8ac9138442c020b6ab9f49c63604eb95 [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>
Hugh Dickins9a840892009-09-21 17:02:01 -070048#include <linux/ksm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070049#include <linux/rmap.h>
50#include <linux/module.h>
Shailabh Nagar0ff92242006-07-14 00:24:37 -070051#include <linux/delayacct.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052#include <linux/init.h>
Peter Zijlstraedc79b22006-09-25 23:30:58 -070053#include <linux/writeback.h>
Balbir Singh8a9f3cc2008-02-07 00:13:53 -080054#include <linux/memcontrol.h>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070055#include <linux/mmu_notifier.h>
Hugh Dickins3dc14742009-01-06 14:40:08 -080056#include <linux/kallsyms.h>
57#include <linux/swapops.h>
58#include <linux/elf.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
Alexey Dobriyan6952b612009-09-18 23:55:55 +040060#include <asm/io.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070061#include <asm/pgalloc.h>
62#include <asm/uaccess.h>
63#include <asm/tlb.h>
64#include <asm/tlbflush.h>
65#include <asm/pgtable.h>
66
Jan Beulich42b77722008-07-23 21:27:10 -070067#include "internal.h"
68
Andy Whitcroftd41dee32005-06-23 00:07:54 -070069#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070070/* use the per-pgdat data instead for discontigmem - mbligh */
71unsigned long max_mapnr;
72struct page *mem_map;
73
74EXPORT_SYMBOL(max_mapnr);
75EXPORT_SYMBOL(mem_map);
76#endif
77
78unsigned long num_physpages;
79/*
80 * A number of key systems in x86 including ioremap() rely on the assumption
81 * that high_memory defines the upper bound on direct map memory, then end
82 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
83 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
84 * and ZONE_HIGHMEM.
85 */
86void * high_memory;
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
88EXPORT_SYMBOL(num_physpages);
89EXPORT_SYMBOL(high_memory);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
Ingo Molnar32a93232008-02-06 22:39:44 +010091/*
92 * Randomize the address space (stacks, mmaps, brk, etc.).
93 *
94 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
95 * as ancient (libc5 based) binaries can segfault. )
96 */
97int randomize_va_space __read_mostly =
98#ifdef CONFIG_COMPAT_BRK
99 1;
100#else
101 2;
102#endif
Andi Kleena62eaf12006-02-16 23:41:58 +0100103
104static int __init disable_randmaps(char *s)
105{
106 randomize_va_space = 0;
OGAWA Hirofumi9b410462006-03-31 02:30:33 -0800107 return 1;
Andi Kleena62eaf12006-02-16 23:41:58 +0100108}
109__setup("norandmaps", disable_randmaps);
110
Hugh Dickins62eede62009-09-21 17:03:34 -0700111unsigned long zero_pfn __read_mostly;
Hugh Dickins03f64622009-09-21 17:03:35 -0700112unsigned long highest_memmap_pfn __read_mostly;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -0700113
114/*
115 * CONFIG_MMU architectures set up ZERO_PAGE in their paging_init()
116 */
117static int __init init_zero_pfn(void)
118{
119 zero_pfn = page_to_pfn(ZERO_PAGE(0));
120 return 0;
121}
122core_initcall(init_zero_pfn);
Andi Kleena62eaf12006-02-16 23:41:58 +0100123
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124/*
125 * If a p?d_bad entry is found while walking page tables, report
126 * the error, before resetting entry to p?d_none. Usually (but
127 * very seldom) called out from the p?d_none_or_clear_bad macros.
128 */
129
130void pgd_clear_bad(pgd_t *pgd)
131{
132 pgd_ERROR(*pgd);
133 pgd_clear(pgd);
134}
135
136void pud_clear_bad(pud_t *pud)
137{
138 pud_ERROR(*pud);
139 pud_clear(pud);
140}
141
142void pmd_clear_bad(pmd_t *pmd)
143{
144 pmd_ERROR(*pmd);
145 pmd_clear(pmd);
146}
147
148/*
149 * Note: this doesn't free the actual pages themselves. That
150 * has been handled earlier when unmapping all the memory regions.
151 */
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000152static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
153 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800155 pgtable_t token = pmd_pgtable(*pmd);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700156 pmd_clear(pmd);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000157 pte_free_tlb(tlb, token, addr);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700158 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159}
160
Hugh Dickinse0da3822005-04-19 13:29:15 -0700161static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
162 unsigned long addr, unsigned long end,
163 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164{
165 pmd_t *pmd;
166 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700167 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700168
Hugh Dickinse0da3822005-04-19 13:29:15 -0700169 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 do {
172 next = pmd_addr_end(addr, end);
173 if (pmd_none_or_clear_bad(pmd))
174 continue;
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000175 free_pte_range(tlb, pmd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 } while (pmd++, addr = next, addr != end);
177
Hugh Dickinse0da3822005-04-19 13:29:15 -0700178 start &= PUD_MASK;
179 if (start < floor)
180 return;
181 if (ceiling) {
182 ceiling &= PUD_MASK;
183 if (!ceiling)
184 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700186 if (end - 1 > ceiling - 1)
187 return;
188
189 pmd = pmd_offset(pud, start);
190 pud_clear(pud);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000191 pmd_free_tlb(tlb, pmd, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192}
193
Hugh Dickinse0da3822005-04-19 13:29:15 -0700194static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
195 unsigned long addr, unsigned long end,
196 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197{
198 pud_t *pud;
199 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700200 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
Hugh Dickinse0da3822005-04-19 13:29:15 -0700202 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204 do {
205 next = pud_addr_end(addr, end);
206 if (pud_none_or_clear_bad(pud))
207 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700208 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209 } while (pud++, addr = next, addr != end);
210
Hugh Dickinse0da3822005-04-19 13:29:15 -0700211 start &= PGDIR_MASK;
212 if (start < floor)
213 return;
214 if (ceiling) {
215 ceiling &= PGDIR_MASK;
216 if (!ceiling)
217 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700219 if (end - 1 > ceiling - 1)
220 return;
221
222 pud = pud_offset(pgd, start);
223 pgd_clear(pgd);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000224 pud_free_tlb(tlb, pud, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225}
226
227/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700228 * This function frees user-level page tables of a process.
229 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230 * Must be called with pagetable lock held.
231 */
Jan Beulich42b77722008-07-23 21:27:10 -0700232void free_pgd_range(struct mmu_gather *tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700233 unsigned long addr, unsigned long end,
234 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235{
236 pgd_t *pgd;
237 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700238 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239
Hugh Dickinse0da3822005-04-19 13:29:15 -0700240 /*
241 * The next few lines have given us lots of grief...
242 *
243 * Why are we testing PMD* at this top level? Because often
244 * there will be no work to do at all, and we'd prefer not to
245 * go all the way down to the bottom just to discover that.
246 *
247 * Why all these "- 1"s? Because 0 represents both the bottom
248 * of the address space and the top of it (using -1 for the
249 * top wouldn't help much: the masks would do the wrong thing).
250 * The rule is that addr 0 and floor 0 refer to the bottom of
251 * the address space, but end 0 and ceiling 0 refer to the top
252 * Comparisons need to use "end - 1" and "ceiling - 1" (though
253 * that end 0 case should be mythical).
254 *
255 * Wherever addr is brought up or ceiling brought down, we must
256 * be careful to reject "the opposite 0" before it confuses the
257 * subsequent tests. But what about where end is brought down
258 * by PMD_SIZE below? no, end can't go down to 0 there.
259 *
260 * Whereas we round start (addr) and ceiling down, by different
261 * masks at different levels, in order to test whether a table
262 * now has no other vmas using it, so can be freed, we don't
263 * bother to round floor or end up - the tests don't need that.
264 */
265
266 addr &= PMD_MASK;
267 if (addr < floor) {
268 addr += PMD_SIZE;
269 if (!addr)
270 return;
271 }
272 if (ceiling) {
273 ceiling &= PMD_MASK;
274 if (!ceiling)
275 return;
276 }
277 if (end - 1 > ceiling - 1)
278 end -= PMD_SIZE;
279 if (addr > end - 1)
280 return;
281
282 start = addr;
Jan Beulich42b77722008-07-23 21:27:10 -0700283 pgd = pgd_offset(tlb->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 do {
285 next = pgd_addr_end(addr, end);
286 if (pgd_none_or_clear_bad(pgd))
287 continue;
Jan Beulich42b77722008-07-23 21:27:10 -0700288 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700290}
291
Jan Beulich42b77722008-07-23 21:27:10 -0700292void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700293 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700294{
295 while (vma) {
296 struct vm_area_struct *next = vma->vm_next;
297 unsigned long addr = vma->vm_start;
298
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700299 /*
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000300 * Hide vma from rmap and truncate_pagecache before freeing
301 * pgtables
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700302 */
303 anon_vma_unlink(vma);
304 unlink_file_vma(vma);
305
David Gibson9da61ae2006-03-22 00:08:57 -0800306 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700307 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700308 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700309 } else {
310 /*
311 * Optimization: gather nearby vmas into one call down
312 */
313 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800314 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700315 vma = next;
316 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700317 anon_vma_unlink(vma);
318 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700319 }
320 free_pgd_range(tlb, addr, vma->vm_end,
321 floor, next? next->vm_start: ceiling);
322 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700323 vma = next;
324 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325}
326
Hugh Dickins1bb36302005-10-29 18:16:22 -0700327int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800329 pgtable_t new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700330 if (!new)
331 return -ENOMEM;
332
Nick Piggin362a61a2008-05-14 06:37:36 +0200333 /*
334 * Ensure all pte setup (eg. pte page lock and page clearing) are
335 * visible before the pte is made visible to other CPUs by being
336 * put into page tables.
337 *
338 * The other side of the story is the pointer chasing in the page
339 * table walking code (when walking the page table without locking;
340 * ie. most of the time). Fortunately, these data accesses consist
341 * of a chain of data-dependent loads, meaning most CPUs (alpha
342 * being the notable exception) will already guarantee loads are
343 * seen in-order. See the alpha page table accessors for the
344 * smp_read_barrier_depends() barriers in page table walking code.
345 */
346 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
347
Hugh Dickinsc74df322005-10-29 18:16:23 -0700348 spin_lock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800349 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 mm->nr_ptes++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 pmd_populate(mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800352 new = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700354 spin_unlock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800355 if (new)
356 pte_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700357 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358}
359
Hugh Dickins1bb36302005-10-29 18:16:22 -0700360int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700362 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
363 if (!new)
364 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365
Nick Piggin362a61a2008-05-14 06:37:36 +0200366 smp_wmb(); /* See comment in __pte_alloc */
367
Hugh Dickins1bb36302005-10-29 18:16:22 -0700368 spin_lock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800369 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Hugh Dickins1bb36302005-10-29 18:16:22 -0700370 pmd_populate_kernel(&init_mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800371 new = NULL;
372 }
Hugh Dickins1bb36302005-10-29 18:16:22 -0700373 spin_unlock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800374 if (new)
375 pte_free_kernel(&init_mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700376 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377}
378
Hugh Dickinsae859762005-10-29 18:16:05 -0700379static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
380{
381 if (file_rss)
382 add_mm_counter(mm, file_rss, file_rss);
383 if (anon_rss)
384 add_mm_counter(mm, anon_rss, anon_rss);
385}
386
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800388 * This function is called to print an error when a bad pte
389 * is found. For example, we might have a PFN-mapped pte in
390 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700391 *
392 * The calling function must still handle the error.
393 */
Hugh Dickins3dc14742009-01-06 14:40:08 -0800394static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
395 pte_t pte, struct page *page)
Nick Pigginb5810032005-10-29 18:16:12 -0700396{
Hugh Dickins3dc14742009-01-06 14:40:08 -0800397 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
398 pud_t *pud = pud_offset(pgd, addr);
399 pmd_t *pmd = pmd_offset(pud, addr);
400 struct address_space *mapping;
401 pgoff_t index;
Hugh Dickinsd936cf92009-01-06 14:40:12 -0800402 static unsigned long resume;
403 static unsigned long nr_shown;
404 static unsigned long nr_unshown;
405
406 /*
407 * Allow a burst of 60 reports, then keep quiet for that minute;
408 * or allow a steady drip of one report per second.
409 */
410 if (nr_shown == 60) {
411 if (time_before(jiffies, resume)) {
412 nr_unshown++;
413 return;
414 }
415 if (nr_unshown) {
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800416 printk(KERN_ALERT
417 "BUG: Bad page map: %lu messages suppressed\n",
Hugh Dickinsd936cf92009-01-06 14:40:12 -0800418 nr_unshown);
419 nr_unshown = 0;
420 }
421 nr_shown = 0;
422 }
423 if (nr_shown++ == 0)
424 resume = jiffies + 60 * HZ;
Hugh Dickins3dc14742009-01-06 14:40:08 -0800425
426 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
427 index = linear_page_index(vma, addr);
428
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800429 printk(KERN_ALERT
430 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800431 current->comm,
432 (long long)pte_val(pte), (long long)pmd_val(*pmd));
433 if (page) {
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800434 printk(KERN_ALERT
Hugh Dickins3dc14742009-01-06 14:40:08 -0800435 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
436 page, (void *)page->flags, page_count(page),
437 page_mapcount(page), page->mapping, page->index);
438 }
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800439 printk(KERN_ALERT
Hugh Dickins3dc14742009-01-06 14:40:08 -0800440 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
441 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
442 /*
443 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
444 */
445 if (vma->vm_ops)
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800446 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800447 (unsigned long)vma->vm_ops->fault);
448 if (vma->vm_file && vma->vm_file->f_op)
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800449 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800450 (unsigned long)vma->vm_file->f_op->mmap);
Nick Pigginb5810032005-10-29 18:16:12 -0700451 dump_stack();
Hugh Dickins3dc14742009-01-06 14:40:08 -0800452 add_taint(TAINT_BAD_PAGE);
Nick Pigginb5810032005-10-29 18:16:12 -0700453}
454
Linus Torvalds67121172005-12-11 20:38:17 -0800455static inline int is_cow_mapping(unsigned int flags)
456{
457 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
458}
459
Hugh Dickins62eede62009-09-21 17:03:34 -0700460#ifndef is_zero_pfn
461static inline int is_zero_pfn(unsigned long pfn)
462{
463 return pfn == zero_pfn;
464}
465#endif
466
467#ifndef my_zero_pfn
468static inline unsigned long my_zero_pfn(unsigned long addr)
469{
470 return zero_pfn;
471}
472#endif
473
Nick Pigginb5810032005-10-29 18:16:12 -0700474/*
Nick Piggin7e675132008-04-28 02:13:00 -0700475 * vm_normal_page -- This function gets the "struct page" associated with a pte.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800476 *
Nick Piggin7e675132008-04-28 02:13:00 -0700477 * "Special" mappings do not wish to be associated with a "struct page" (either
478 * it doesn't exist, or it exists but they don't want to touch it). In this
479 * case, NULL is returned here. "Normal" mappings do have a struct page.
Jared Hulbertb379d792008-04-28 02:12:58 -0700480 *
Nick Piggin7e675132008-04-28 02:13:00 -0700481 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
482 * pte bit, in which case this function is trivial. Secondly, an architecture
483 * may not have a spare pte bit, which requires a more complicated scheme,
484 * described below.
485 *
486 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
487 * special mapping (even if there are underlying and valid "struct pages").
488 * COWed pages of a VM_PFNMAP are always normal.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800489 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700490 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
491 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
Nick Piggin7e675132008-04-28 02:13:00 -0700492 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
493 * mapping will always honor the rule
Linus Torvalds6aab3412005-11-28 14:34:23 -0800494 *
495 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
496 *
Nick Piggin7e675132008-04-28 02:13:00 -0700497 * And for normal mappings this is false.
Jared Hulbertb379d792008-04-28 02:12:58 -0700498 *
Nick Piggin7e675132008-04-28 02:13:00 -0700499 * This restricts such mappings to be a linear translation from virtual address
500 * to pfn. To get around this restriction, we allow arbitrary mappings so long
501 * as the vma is not a COW mapping; in that case, we know that all ptes are
502 * special (because none can have been COWed).
Jared Hulbertb379d792008-04-28 02:12:58 -0700503 *
504 *
Nick Piggin7e675132008-04-28 02:13:00 -0700505 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
506 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700507 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
508 * page" backing, however the difference is that _all_ pages with a struct
509 * page (that is, those where pfn_valid is true) are refcounted and considered
510 * normal pages by the VM. The disadvantage is that pages are refcounted
511 * (which can be slower and simply not an option for some PFNMAP users). The
512 * advantage is that we don't have to follow the strict linearity rule of
513 * PFNMAP mappings in order to support COWable mappings.
514 *
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800515 */
Nick Piggin7e675132008-04-28 02:13:00 -0700516#ifdef __HAVE_ARCH_PTE_SPECIAL
517# define HAVE_PTE_SPECIAL 1
518#else
519# define HAVE_PTE_SPECIAL 0
520#endif
521struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
522 pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800523{
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800524 unsigned long pfn = pte_pfn(pte);
Nick Piggin7e675132008-04-28 02:13:00 -0700525
526 if (HAVE_PTE_SPECIAL) {
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800527 if (likely(!pte_special(pte)))
528 goto check_pfn;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -0700529 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
530 return NULL;
Hugh Dickins62eede62009-09-21 17:03:34 -0700531 if (!is_zero_pfn(pfn))
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800532 print_bad_pte(vma, addr, pte, NULL);
Nick Piggin7e675132008-04-28 02:13:00 -0700533 return NULL;
534 }
535
536 /* !HAVE_PTE_SPECIAL case follows: */
537
Jared Hulbertb379d792008-04-28 02:12:58 -0700538 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
539 if (vma->vm_flags & VM_MIXEDMAP) {
540 if (!pfn_valid(pfn))
541 return NULL;
542 goto out;
543 } else {
Nick Piggin7e675132008-04-28 02:13:00 -0700544 unsigned long off;
545 off = (addr - vma->vm_start) >> PAGE_SHIFT;
Jared Hulbertb379d792008-04-28 02:12:58 -0700546 if (pfn == vma->vm_pgoff + off)
547 return NULL;
548 if (!is_cow_mapping(vma->vm_flags))
549 return NULL;
550 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800551 }
552
Hugh Dickins62eede62009-09-21 17:03:34 -0700553 if (is_zero_pfn(pfn))
554 return NULL;
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800555check_pfn:
556 if (unlikely(pfn > highest_memmap_pfn)) {
557 print_bad_pte(vma, addr, pte, NULL);
558 return NULL;
559 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800560
561 /*
Nick Piggin7e675132008-04-28 02:13:00 -0700562 * NOTE! We still have PageReserved() pages in the page tables.
Nick Piggin7e675132008-04-28 02:13:00 -0700563 * eg. VDSO mappings can cause them to exist.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800564 */
Jared Hulbertb379d792008-04-28 02:12:58 -0700565out:
Linus Torvalds6aab3412005-11-28 14:34:23 -0800566 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800567}
568
569/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 * copy one vm_area from one task to the other. Assumes the page tables
571 * already present in the new task to be cleared in the whole range
572 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 */
574
Hugh Dickins570a3352009-12-14 17:58:46 -0800575static inline unsigned long
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700577 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700578 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579{
Nick Pigginb5810032005-10-29 18:16:12 -0700580 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 pte_t pte = *src_pte;
582 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583
584 /* pte contains position in swap or file, so copy. */
585 if (unlikely(!pte_present(pte))) {
586 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700587 swp_entry_t entry = pte_to_swp_entry(pte);
588
Hugh Dickins570a3352009-12-14 17:58:46 -0800589 if (swap_duplicate(entry) < 0)
590 return entry.val;
591
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 /* make sure dst_mm is on swapoff's mmlist. */
593 if (unlikely(list_empty(&dst_mm->mmlist))) {
594 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700595 if (list_empty(&dst_mm->mmlist))
596 list_add(&dst_mm->mmlist,
597 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 spin_unlock(&mmlist_lock);
599 }
Christoph Lameter06972122006-06-23 02:03:35 -0700600 if (is_write_migration_entry(entry) &&
601 is_cow_mapping(vm_flags)) {
602 /*
603 * COW mappings require pages in both parent
604 * and child to be set to read.
605 */
606 make_migration_entry_read(&entry);
607 pte = swp_entry_to_pte(entry);
608 set_pte_at(src_mm, addr, src_pte, pte);
609 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700611 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 }
613
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 /*
615 * If it's a COW mapping, write protect it both
616 * in the parent and the child
617 */
Linus Torvalds67121172005-12-11 20:38:17 -0800618 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700619 ptep_set_wrprotect(src_mm, addr, src_pte);
Zachary Amsden3dc90792006-09-30 23:29:30 -0700620 pte = pte_wrprotect(pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621 }
622
623 /*
624 * If it's a shared mapping, mark it clean in
625 * the child
626 */
627 if (vm_flags & VM_SHARED)
628 pte = pte_mkclean(pte);
629 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800630
631 page = vm_normal_page(vma, addr, pte);
632 if (page) {
633 get_page(page);
Hugh Dickins21333b22009-09-21 17:01:59 -0700634 page_dup_rmap(page);
Johannes Weinerb7c46d12009-09-21 17:02:56 -0700635 rss[PageAnon(page)]++;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800636 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700637
638out_set_pte:
639 set_pte_at(dst_mm, addr, dst_pte, pte);
Hugh Dickins570a3352009-12-14 17:58:46 -0800640 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641}
642
643static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
644 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
645 unsigned long addr, unsigned long end)
646{
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700647 pte_t *orig_src_pte, *orig_dst_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700649 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700650 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700651 int rss[2];
Hugh Dickins570a3352009-12-14 17:58:46 -0800652 swp_entry_t entry = (swp_entry_t){0};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700653
654again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700655 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700656 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657 if (!dst_pte)
658 return -ENOMEM;
659 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700660 src_ptl = pte_lockptr(src_mm, src_pmd);
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700661 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700662 orig_src_pte = src_pte;
663 orig_dst_pte = dst_pte;
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700664 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 do {
667 /*
668 * We are holding two locks at this point - either of them
669 * could generate latencies in another task on another CPU.
670 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700671 if (progress >= 32) {
672 progress = 0;
673 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100674 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700675 break;
676 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 if (pte_none(*src_pte)) {
678 progress++;
679 continue;
680 }
Hugh Dickins570a3352009-12-14 17:58:46 -0800681 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
682 vma, addr, rss);
683 if (entry.val)
684 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685 progress += 8;
686 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700688 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -0700689 spin_unlock(src_ptl);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700690 pte_unmap_nested(orig_src_pte);
Hugh Dickinsae859762005-10-29 18:16:05 -0700691 add_mm_rss(dst_mm, rss[0], rss[1]);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700692 pte_unmap_unlock(orig_dst_pte, dst_ptl);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700693 cond_resched();
Hugh Dickins570a3352009-12-14 17:58:46 -0800694
695 if (entry.val) {
696 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
697 return -ENOMEM;
698 progress = 0;
699 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 if (addr != end)
701 goto again;
702 return 0;
703}
704
705static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
706 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
707 unsigned long addr, unsigned long end)
708{
709 pmd_t *src_pmd, *dst_pmd;
710 unsigned long next;
711
712 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
713 if (!dst_pmd)
714 return -ENOMEM;
715 src_pmd = pmd_offset(src_pud, addr);
716 do {
717 next = pmd_addr_end(addr, end);
718 if (pmd_none_or_clear_bad(src_pmd))
719 continue;
720 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
721 vma, addr, next))
722 return -ENOMEM;
723 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
724 return 0;
725}
726
727static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
728 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
729 unsigned long addr, unsigned long end)
730{
731 pud_t *src_pud, *dst_pud;
732 unsigned long next;
733
734 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
735 if (!dst_pud)
736 return -ENOMEM;
737 src_pud = pud_offset(src_pgd, addr);
738 do {
739 next = pud_addr_end(addr, end);
740 if (pud_none_or_clear_bad(src_pud))
741 continue;
742 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
743 vma, addr, next))
744 return -ENOMEM;
745 } while (dst_pud++, src_pud++, addr = next, addr != end);
746 return 0;
747}
748
749int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
750 struct vm_area_struct *vma)
751{
752 pgd_t *src_pgd, *dst_pgd;
753 unsigned long next;
754 unsigned long addr = vma->vm_start;
755 unsigned long end = vma->vm_end;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700756 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757
Nick Piggind9928952005-08-28 16:49:11 +1000758 /*
759 * Don't copy ptes where a page fault will fill them correctly.
760 * Fork becomes much lighter when there are big shared or private
761 * readonly mappings. The tradeoff is that copy_page_range is more
762 * efficient than faulting.
763 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800764 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000765 if (!vma->anon_vma)
766 return 0;
767 }
768
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 if (is_vm_hugetlb_page(vma))
770 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
771
venkatesh.pallipadi@intel.com34801ba2008-12-19 13:47:29 -0800772 if (unlikely(is_pfn_mapping(vma))) {
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -0800773 /*
774 * We do not free on error cases below as remove_vma
775 * gets called on error from higher level routine
776 */
777 ret = track_pfn_vma_copy(vma);
778 if (ret)
779 return ret;
780 }
781
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700782 /*
783 * We need to invalidate the secondary MMU mappings only when
784 * there could be a permission downgrade on the ptes of the
785 * parent mm. And a permission downgrade will only happen if
786 * is_cow_mapping() returns true.
787 */
788 if (is_cow_mapping(vma->vm_flags))
789 mmu_notifier_invalidate_range_start(src_mm, addr, end);
790
791 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 dst_pgd = pgd_offset(dst_mm, addr);
793 src_pgd = pgd_offset(src_mm, addr);
794 do {
795 next = pgd_addr_end(addr, end);
796 if (pgd_none_or_clear_bad(src_pgd))
797 continue;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700798 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
799 vma, addr, next))) {
800 ret = -ENOMEM;
801 break;
802 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700804
805 if (is_cow_mapping(vma->vm_flags))
806 mmu_notifier_invalidate_range_end(src_mm,
807 vma->vm_start, end);
808 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809}
810
Robin Holt51c6f662005-11-13 16:06:42 -0800811static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700812 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800814 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815{
Nick Pigginb5810032005-10-29 18:16:12 -0700816 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700818 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700819 int file_rss = 0;
820 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821
Hugh Dickins508034a2005-10-29 18:16:30 -0700822 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700823 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824 do {
825 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800826 if (pte_none(ptent)) {
827 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800829 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800830
831 (*zap_work) -= PAGE_SIZE;
832
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800834 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800835
Linus Torvalds6aab3412005-11-28 14:34:23 -0800836 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837 if (unlikely(details) && page) {
838 /*
839 * unmap_shared_mapping_pages() wants to
840 * invalidate cache without truncating:
841 * unmap shared but keep private pages.
842 */
843 if (details->check_mapping &&
844 details->check_mapping != page->mapping)
845 continue;
846 /*
847 * Each page->index must be checked when
848 * invalidating or truncating nonlinear.
849 */
850 if (details->nonlinear_vma &&
851 (page->index < details->first_index ||
852 page->index > details->last_index))
853 continue;
854 }
Nick Pigginb5810032005-10-29 18:16:12 -0700855 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700856 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 tlb_remove_tlb_entry(tlb, pte, addr);
858 if (unlikely(!page))
859 continue;
860 if (unlikely(details) && details->nonlinear_vma
861 && linear_page_index(details->nonlinear_vma,
862 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700863 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700866 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700867 else {
868 if (pte_dirty(ptent))
869 set_page_dirty(page);
Johannes Weiner4917e5d2009-01-06 14:39:17 -0800870 if (pte_young(ptent) &&
871 likely(!VM_SequentialReadHint(vma)))
Nick Pigginbf3f3bc2009-01-06 14:38:55 -0800872 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700873 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700874 }
Hugh Dickinsedc315f2009-01-06 14:40:11 -0800875 page_remove_rmap(page);
Hugh Dickins3dc14742009-01-06 14:40:08 -0800876 if (unlikely(page_mapcount(page) < 0))
877 print_bad_pte(vma, addr, ptent, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 tlb_remove_page(tlb, page);
879 continue;
880 }
881 /*
882 * If details->check_mapping, we leave swap entries;
883 * if details->nonlinear_vma, we leave file entries.
884 */
885 if (unlikely(details))
886 continue;
Hugh Dickins2509ef22009-01-06 14:40:10 -0800887 if (pte_file(ptent)) {
888 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
889 print_bad_pte(vma, addr, ptent, NULL);
890 } else if
891 (unlikely(!free_swap_and_cache(pte_to_swp_entry(ptent))))
892 print_bad_pte(vma, addr, ptent, NULL);
Zachary Amsden9888a1c2006-09-30 23:29:31 -0700893 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800894 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700895
Hugh Dickins86d912f2005-10-29 18:16:14 -0700896 add_mm_rss(mm, file_rss, anon_rss);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700897 arch_leave_lazy_mmu_mode();
Hugh Dickins508034a2005-10-29 18:16:30 -0700898 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800899
900 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901}
902
Robin Holt51c6f662005-11-13 16:06:42 -0800903static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700904 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800906 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907{
908 pmd_t *pmd;
909 unsigned long next;
910
911 pmd = pmd_offset(pud, addr);
912 do {
913 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800914 if (pmd_none_or_clear_bad(pmd)) {
915 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800917 }
918 next = zap_pte_range(tlb, vma, pmd, addr, next,
919 zap_work, details);
920 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
921
922 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923}
924
Robin Holt51c6f662005-11-13 16:06:42 -0800925static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700926 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800928 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929{
930 pud_t *pud;
931 unsigned long next;
932
933 pud = pud_offset(pgd, addr);
934 do {
935 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800936 if (pud_none_or_clear_bad(pud)) {
937 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800939 }
940 next = zap_pmd_range(tlb, vma, pud, addr, next,
941 zap_work, details);
942 } while (pud++, addr = next, (addr != end && *zap_work > 0));
943
944 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945}
946
Robin Holt51c6f662005-11-13 16:06:42 -0800947static unsigned long unmap_page_range(struct mmu_gather *tlb,
948 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800950 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951{
952 pgd_t *pgd;
953 unsigned long next;
954
955 if (details && !details->check_mapping && !details->nonlinear_vma)
956 details = NULL;
957
958 BUG_ON(addr >= end);
KAMEZAWA Hiroyuki569b8462009-12-15 16:47:03 -0800959 mem_cgroup_uncharge_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 tlb_start_vma(tlb, vma);
961 pgd = pgd_offset(vma->vm_mm, addr);
962 do {
963 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800964 if (pgd_none_or_clear_bad(pgd)) {
965 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800967 }
968 next = zap_pud_range(tlb, vma, pgd, addr, next,
969 zap_work, details);
970 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 tlb_end_vma(tlb, vma);
KAMEZAWA Hiroyuki569b8462009-12-15 16:47:03 -0800972 mem_cgroup_uncharge_end();
Robin Holt51c6f662005-11-13 16:06:42 -0800973
974 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975}
976
977#ifdef CONFIG_PREEMPT
978# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
979#else
980/* No preempt: go for improved straight-line efficiency */
981# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
982#endif
983
984/**
985 * unmap_vmas - unmap a range of memory covered by a list of vma's
986 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 * @vma: the starting vma
988 * @start_addr: virtual address at which to start unmapping
989 * @end_addr: virtual address at which to end unmapping
990 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
991 * @details: details of nonlinear truncation or shared cache invalidation
992 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700993 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700995 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700997 * We aim to not hold locks for too long (for scheduling latency reasons).
998 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 * return the ending mmu_gather to the caller.
1000 *
1001 * Only addresses between `start' and `end' will be unmapped.
1002 *
1003 * The VMA list must be sorted in ascending virtual address order.
1004 *
1005 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1006 * range after unmap_vmas() returns. So the only responsibility here is to
1007 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1008 * drops the lock and schedules.
1009 */
Hugh Dickins508034a2005-10-29 18:16:30 -07001010unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 struct vm_area_struct *vma, unsigned long start_addr,
1012 unsigned long end_addr, unsigned long *nr_accounted,
1013 struct zap_details *details)
1014{
Robin Holt51c6f662005-11-13 16:06:42 -08001015 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
1017 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07001018 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001019 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -07001020 int fullmm = (*tlbp)->fullmm;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001021 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001023 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001024 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 unsigned long end;
1026
1027 start = max(vma->vm_start, start_addr);
1028 if (start >= vma->vm_end)
1029 continue;
1030 end = min(vma->vm_end, end_addr);
1031 if (end <= vma->vm_start)
1032 continue;
1033
1034 if (vma->vm_flags & VM_ACCOUNT)
1035 *nr_accounted += (end - start) >> PAGE_SHIFT;
1036
venkatesh.pallipadi@intel.com34801ba2008-12-19 13:47:29 -08001037 if (unlikely(is_pfn_mapping(vma)))
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001038 untrack_pfn_vma(vma, 0, 0);
1039
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 if (!tlb_start_valid) {
1042 tlb_start = start;
1043 tlb_start_valid = 1;
1044 }
1045
Robin Holt51c6f662005-11-13 16:06:42 -08001046 if (unlikely(is_vm_hugetlb_page(vma))) {
Andi Kleena137e1c2008-07-23 21:27:43 -07001047 /*
1048 * It is undesirable to test vma->vm_file as it
1049 * should be non-null for valid hugetlb area.
1050 * However, vm_file will be NULL in the error
1051 * cleanup path of do_mmap_pgoff. When
1052 * hugetlbfs ->mmap method fails,
1053 * do_mmap_pgoff() nullifies vma->vm_file
1054 * before calling this function to clean up.
1055 * Since no pte has actually been setup, it is
1056 * safe to do nothing in this case.
1057 */
1058 if (vma->vm_file) {
1059 unmap_hugepage_range(vma, start, end, NULL);
1060 zap_work -= (end - start) /
Andi Kleena5516432008-07-23 21:27:41 -07001061 pages_per_huge_page(hstate_vma(vma));
Andi Kleena137e1c2008-07-23 21:27:43 -07001062 }
1063
Robin Holt51c6f662005-11-13 16:06:42 -08001064 start = end;
1065 } else
1066 start = unmap_page_range(*tlbp, vma,
1067 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068
Robin Holt51c6f662005-11-13 16:06:42 -08001069 if (zap_work > 0) {
1070 BUG_ON(start != end);
1071 break;
1072 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001073
1074 tlb_finish_mmu(*tlbp, tlb_start, start);
1075
1076 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +01001077 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -07001079 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080 goto out;
1081 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001082 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 }
1084
Hugh Dickins508034a2005-10-29 18:16:30 -07001085 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -08001087 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 }
1089 }
1090out:
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001091 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001092 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093}
1094
1095/**
1096 * zap_page_range - remove user pages in a given range
1097 * @vma: vm_area_struct holding the applicable pages
1098 * @address: starting address of pages to zap
1099 * @size: number of bytes to zap
1100 * @details: details of nonlinear truncation or shared cache invalidation
1101 */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001102unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 unsigned long size, struct zap_details *details)
1104{
1105 struct mm_struct *mm = vma->vm_mm;
1106 struct mmu_gather *tlb;
1107 unsigned long end = address + size;
1108 unsigned long nr_accounted = 0;
1109
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001112 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001113 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
1114 if (tlb)
1115 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001116 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117}
1118
Jack Steinerc627f9c2008-07-29 22:33:53 -07001119/**
1120 * zap_vma_ptes - remove ptes mapping the vma
1121 * @vma: vm_area_struct holding ptes to be zapped
1122 * @address: starting address of pages to zap
1123 * @size: number of bytes to zap
1124 *
1125 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1126 *
1127 * The entire address range must be fully contained within the vma.
1128 *
1129 * Returns 0 if successful.
1130 */
1131int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1132 unsigned long size)
1133{
1134 if (address < vma->vm_start || address + size > vma->vm_end ||
1135 !(vma->vm_flags & VM_PFNMAP))
1136 return -1;
1137 zap_page_range(vma, address, size, NULL);
1138 return 0;
1139}
1140EXPORT_SYMBOL_GPL(zap_vma_ptes);
1141
Linus Torvalds1da177e2005-04-16 15:20:36 -07001142/*
1143 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001144 */
Linus Torvalds6aab3412005-11-28 14:34:23 -08001145struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001146 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147{
1148 pgd_t *pgd;
1149 pud_t *pud;
1150 pmd_t *pmd;
1151 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001152 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001154 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001156 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1157 if (!IS_ERR(page)) {
1158 BUG_ON(flags & FOLL_GET);
1159 goto out;
1160 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001161
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001162 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001163 pgd = pgd_offset(mm, address);
1164 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001165 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166
1167 pud = pud_offset(pgd, address);
Andi Kleenceb86872008-07-23 21:27:50 -07001168 if (pud_none(*pud))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001169 goto no_page_table;
Andi Kleenceb86872008-07-23 21:27:50 -07001170 if (pud_huge(*pud)) {
1171 BUG_ON(flags & FOLL_GET);
1172 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1173 goto out;
1174 }
1175 if (unlikely(pud_bad(*pud)))
1176 goto no_page_table;
1177
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 pmd = pmd_offset(pud, address);
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001179 if (pmd_none(*pmd))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001180 goto no_page_table;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001181 if (pmd_huge(*pmd)) {
1182 BUG_ON(flags & FOLL_GET);
1183 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1184 goto out;
1185 }
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001186 if (unlikely(pmd_bad(*pmd)))
1187 goto no_page_table;
1188
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001189 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190
1191 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001192 if (!pte_present(pte))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001193 goto no_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001194 if ((flags & FOLL_WRITE) && !pte_write(pte))
1195 goto unlock;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001196
Linus Torvalds6aab3412005-11-28 14:34:23 -08001197 page = vm_normal_page(vma, address, pte);
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001198 if (unlikely(!page)) {
1199 if ((flags & FOLL_DUMP) ||
Hugh Dickins62eede62009-09-21 17:03:34 -07001200 !is_zero_pfn(pte_pfn(pte)))
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001201 goto bad_page;
1202 page = pte_page(pte);
1203 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001204
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001205 if (flags & FOLL_GET)
1206 get_page(page);
1207 if (flags & FOLL_TOUCH) {
1208 if ((flags & FOLL_WRITE) &&
1209 !pte_dirty(pte) && !PageDirty(page))
1210 set_page_dirty(page);
KOSAKI Motohirobd775c42009-03-31 15:19:37 -07001211 /*
1212 * pte_mkyoung() would be more correct here, but atomic care
1213 * is needed to avoid losing the dirty bit: it is easier to use
1214 * mark_page_accessed().
1215 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001216 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001217 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001218unlock:
1219 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001221 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001223bad_page:
1224 pte_unmap_unlock(ptep, ptl);
1225 return ERR_PTR(-EFAULT);
1226
1227no_page:
1228 pte_unmap_unlock(ptep, ptl);
1229 if (!pte_none(pte))
1230 return page;
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001231
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001232no_page_table:
1233 /*
1234 * When core dumping an enormous anonymous area that nobody
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001235 * has touched so far, we don't want to allocate unnecessary pages or
1236 * page tables. Return error instead of NULL to skip handle_mm_fault,
1237 * then get_dump_page() will return NULL to leave a hole in the dump.
1238 * But we can only make this optimization where a hole would surely
1239 * be zero-filled if handle_mm_fault() actually did handle it.
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001240 */
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001241 if ((flags & FOLL_DUMP) &&
1242 (!vma->vm_ops || !vma->vm_ops->fault))
1243 return ERR_PTR(-EFAULT);
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001244 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001245}
1246
Nick Pigginb291f002008-10-18 20:26:44 -07001247int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001248 unsigned long start, int nr_pages, unsigned int gup_flags,
Peter Zijlstra9d737772009-06-25 11:58:55 +02001249 struct page **pages, struct vm_area_struct **vmas)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250{
1251 int i;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001252 unsigned long vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253
Peter Zijlstra9d737772009-06-25 11:58:55 +02001254 if (nr_pages <= 0)
Jonathan Corbet900cf082008-02-11 16:17:33 -07001255 return 0;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001256
1257 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1258
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 /*
1260 * Require read or write permissions.
Hugh Dickins58fa8792009-09-21 17:03:31 -07001261 * If FOLL_FORCE is set, we only require the "MAY" flags.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001262 */
Hugh Dickins58fa8792009-09-21 17:03:31 -07001263 vm_flags = (gup_flags & FOLL_WRITE) ?
1264 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1265 vm_flags &= (gup_flags & FOLL_FORCE) ?
1266 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 i = 0;
1268
1269 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001270 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001271
1272 vma = find_extend_vma(mm, start);
1273 if (!vma && in_gate_area(tsk, start)) {
1274 unsigned long pg = start & PAGE_MASK;
1275 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1276 pgd_t *pgd;
1277 pud_t *pud;
1278 pmd_t *pmd;
1279 pte_t *pte;
Nick Pigginb291f002008-10-18 20:26:44 -07001280
1281 /* user gate pages are read-only */
Hugh Dickins58fa8792009-09-21 17:03:31 -07001282 if (gup_flags & FOLL_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001283 return i ? : -EFAULT;
1284 if (pg > TASK_SIZE)
1285 pgd = pgd_offset_k(pg);
1286 else
1287 pgd = pgd_offset_gate(mm, pg);
1288 BUG_ON(pgd_none(*pgd));
1289 pud = pud_offset(pgd, pg);
1290 BUG_ON(pud_none(*pud));
1291 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001292 if (pmd_none(*pmd))
1293 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001294 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001295 if (pte_none(*pte)) {
1296 pte_unmap(pte);
1297 return i ? : -EFAULT;
1298 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001299 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001300 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001301 pages[i] = page;
1302 if (page)
1303 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 }
1305 pte_unmap(pte);
1306 if (vmas)
1307 vmas[i] = gate_vma;
1308 i++;
1309 start += PAGE_SIZE;
Peter Zijlstra9d737772009-06-25 11:58:55 +02001310 nr_pages--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 continue;
1312 }
1313
Nick Pigginb291f002008-10-18 20:26:44 -07001314 if (!vma ||
1315 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001316 !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001317 return i ? : -EFAULT;
1318
Hugh Dickins2a15efc2009-09-21 17:03:27 -07001319 if (is_vm_hugetlb_page(vma)) {
1320 i = follow_hugetlb_page(mm, vma, pages, vmas,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001321 &start, &nr_pages, i, gup_flags);
Hugh Dickins2a15efc2009-09-21 17:03:27 -07001322 continue;
1323 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001324
Linus Torvalds1da177e2005-04-16 15:20:36 -07001325 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001326 struct page *page;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001327 unsigned int foll_flags = gup_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328
Ethan Solomita462e00c2007-07-15 23:38:16 -07001329 /*
Ying Han47792802009-01-06 14:40:18 -08001330 * If we have a pending SIGKILL, don't keep faulting
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001331 * pages and potentially allocating memory.
Ethan Solomita462e00c2007-07-15 23:38:16 -07001332 */
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001333 if (unlikely(fatal_signal_pending(current)))
Ying Han47792802009-01-06 14:40:18 -08001334 return i ? i : -ERESTARTSYS;
Ethan Solomita462e00c2007-07-15 23:38:16 -07001335
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001336 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001337 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001338 int ret;
Linus Torvaldsd06063c2009-04-10 09:01:23 -07001339
Hugh Dickinsd26ed652009-06-23 13:52:49 +01001340 ret = handle_mm_fault(mm, vma, start,
1341 (foll_flags & FOLL_WRITE) ?
1342 FAULT_FLAG_WRITE : 0);
1343
Nick Piggin83c54072007-07-19 01:47:05 -07001344 if (ret & VM_FAULT_ERROR) {
1345 if (ret & VM_FAULT_OOM)
1346 return i ? i : -ENOMEM;
Andi Kleend1737fd2009-09-16 11:50:06 +02001347 if (ret &
1348 (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
Nick Piggin83c54072007-07-19 01:47:05 -07001349 return i ? i : -EFAULT;
1350 BUG();
1351 }
1352 if (ret & VM_FAULT_MAJOR)
1353 tsk->maj_flt++;
1354 else
1355 tsk->min_flt++;
1356
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001357 /*
Nick Piggin83c54072007-07-19 01:47:05 -07001358 * The VM_FAULT_WRITE bit tells us that
1359 * do_wp_page has broken COW when necessary,
1360 * even if maybe_mkwrite decided not to set
1361 * pte_write. We can thus safely do subsequent
Hugh Dickins878b63a2009-01-06 14:39:32 -08001362 * page lookups as if they were reads. But only
1363 * do so when looping for pte_write is futile:
1364 * in some cases userspace may also be wanting
1365 * to write to the gotten user page, which a
1366 * read fault here might prevent (a readonly
1367 * page might get reCOWed by userspace write).
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001368 */
Hugh Dickins878b63a2009-01-06 14:39:32 -08001369 if ((ret & VM_FAULT_WRITE) &&
1370 !(vma->vm_flags & VM_WRITE))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001371 foll_flags &= ~FOLL_WRITE;
Nick Piggin83c54072007-07-19 01:47:05 -07001372
Benjamin Herrenschmidt7f7bbbe2006-10-06 00:43:53 -07001373 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001374 }
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001375 if (IS_ERR(page))
1376 return i ? i : PTR_ERR(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001378 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001379
Russell Kinga6f36be2006-12-30 22:24:19 +00001380 flush_anon_page(vma, page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001381 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001382 }
1383 if (vmas)
1384 vmas[i] = vma;
1385 i++;
1386 start += PAGE_SIZE;
Peter Zijlstra9d737772009-06-25 11:58:55 +02001387 nr_pages--;
1388 } while (nr_pages && start < vma->vm_end);
1389 } while (nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001390 return i;
1391}
Nick Pigginb291f002008-10-18 20:26:44 -07001392
Nick Piggind2bf6be2009-06-16 15:31:39 -07001393/**
1394 * get_user_pages() - pin user pages in memory
1395 * @tsk: task_struct of target task
1396 * @mm: mm_struct of target mm
1397 * @start: starting user address
Peter Zijlstra9d737772009-06-25 11:58:55 +02001398 * @nr_pages: number of pages from start to pin
Nick Piggind2bf6be2009-06-16 15:31:39 -07001399 * @write: whether pages will be written to by the caller
1400 * @force: whether to force write access even if user mapping is
1401 * readonly. This will result in the page being COWed even
1402 * in MAP_SHARED mappings. You do not want this.
1403 * @pages: array that receives pointers to the pages pinned.
1404 * Should be at least nr_pages long. Or NULL, if caller
1405 * only intends to ensure the pages are faulted in.
1406 * @vmas: array of pointers to vmas corresponding to each page.
1407 * Or NULL if the caller does not require them.
1408 *
1409 * Returns number of pages pinned. This may be fewer than the number
Peter Zijlstra9d737772009-06-25 11:58:55 +02001410 * requested. If nr_pages is 0 or negative, returns 0. If no pages
Nick Piggind2bf6be2009-06-16 15:31:39 -07001411 * were pinned, returns -errno. Each page returned must be released
1412 * with a put_page() call when it is finished with. vmas will only
1413 * remain valid while mmap_sem is held.
1414 *
1415 * Must be called with mmap_sem held for read or write.
1416 *
1417 * get_user_pages walks a process's page tables and takes a reference to
1418 * each struct page that each user address corresponds to at a given
1419 * instant. That is, it takes the page that would be accessed if a user
1420 * thread accesses the given user virtual address at that instant.
1421 *
1422 * This does not guarantee that the page exists in the user mappings when
1423 * get_user_pages returns, and there may even be a completely different
1424 * page there in some cases (eg. if mmapped pagecache has been invalidated
1425 * and subsequently re faulted). However it does guarantee that the page
1426 * won't be freed completely. And mostly callers simply care that the page
1427 * contains data that was valid *at some point in time*. Typically, an IO
1428 * or similar operation cannot guarantee anything stronger anyway because
1429 * locks can't be held over the syscall boundary.
1430 *
1431 * If write=0, the page must not be written to. If the page is written to,
1432 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1433 * after the page is finished with, and before put_page is called.
1434 *
1435 * get_user_pages is typically used for fewer-copy IO operations, to get a
1436 * handle on the memory by some means other than accesses via the user virtual
1437 * addresses. The pages may be submitted for DMA to devices or accessed via
1438 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1439 * use the correct cache flushing APIs.
1440 *
1441 * See also get_user_pages_fast, for performance critical applications.
1442 */
Nick Pigginb291f002008-10-18 20:26:44 -07001443int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Peter Zijlstra9d737772009-06-25 11:58:55 +02001444 unsigned long start, int nr_pages, int write, int force,
Nick Pigginb291f002008-10-18 20:26:44 -07001445 struct page **pages, struct vm_area_struct **vmas)
1446{
Hugh Dickins58fa8792009-09-21 17:03:31 -07001447 int flags = FOLL_TOUCH;
Nick Pigginb291f002008-10-18 20:26:44 -07001448
Hugh Dickins58fa8792009-09-21 17:03:31 -07001449 if (pages)
1450 flags |= FOLL_GET;
Nick Pigginb291f002008-10-18 20:26:44 -07001451 if (write)
Hugh Dickins58fa8792009-09-21 17:03:31 -07001452 flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -07001453 if (force)
Hugh Dickins58fa8792009-09-21 17:03:31 -07001454 flags |= FOLL_FORCE;
Nick Pigginb291f002008-10-18 20:26:44 -07001455
Peter Zijlstra9d737772009-06-25 11:58:55 +02001456 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
Nick Pigginb291f002008-10-18 20:26:44 -07001457}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458EXPORT_SYMBOL(get_user_pages);
1459
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001460/**
1461 * get_dump_page() - pin user page in memory while writing it to core dump
1462 * @addr: user address
1463 *
1464 * Returns struct page pointer of user page pinned for dump,
1465 * to be freed afterwards by page_cache_release() or put_page().
1466 *
1467 * Returns NULL on any kind of failure - a hole must then be inserted into
1468 * the corefile, to preserve alignment with its headers; and also returns
1469 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
1470 * allowing a hole to be left in the corefile to save diskspace.
1471 *
1472 * Called without mmap_sem, but after all other threads have been killed.
1473 */
1474#ifdef CONFIG_ELF_CORE
1475struct page *get_dump_page(unsigned long addr)
1476{
1477 struct vm_area_struct *vma;
1478 struct page *page;
1479
1480 if (__get_user_pages(current, current->mm, addr, 1,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001481 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001482 return NULL;
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001483 flush_cache_page(vma, addr, page_to_pfn(page));
1484 return page;
1485}
1486#endif /* CONFIG_ELF_CORE */
1487
Harvey Harrison920c7a52008-02-04 22:29:26 -08001488pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1489 spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001490{
1491 pgd_t * pgd = pgd_offset(mm, addr);
1492 pud_t * pud = pud_alloc(mm, pgd, addr);
1493 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001494 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001495 if (pmd)
1496 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1497 }
1498 return NULL;
1499}
1500
Linus Torvalds1da177e2005-04-16 15:20:36 -07001501/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001502 * This is the old fallback for page remapping.
1503 *
1504 * For historical reasons, it only allows reserved pages. Only
1505 * old drivers should use this, and they needed to mark their
1506 * pages reserved for the old functions anyway.
1507 */
Nick Piggin423bad62008-04-28 02:13:01 -07001508static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1509 struct page *page, pgprot_t prot)
Linus Torvalds238f58d2005-11-29 13:01:56 -08001510{
Nick Piggin423bad62008-04-28 02:13:01 -07001511 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001512 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001513 pte_t *pte;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001514 spinlock_t *ptl;
1515
Linus Torvalds238f58d2005-11-29 13:01:56 -08001516 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001517 if (PageAnon(page))
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07001518 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001519 retval = -ENOMEM;
1520 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001521 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001522 if (!pte)
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07001523 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001524 retval = -EBUSY;
1525 if (!pte_none(*pte))
1526 goto out_unlock;
1527
1528 /* Ok, finally just insert the thing.. */
1529 get_page(page);
1530 inc_mm_counter(mm, file_rss);
1531 page_add_file_rmap(page);
1532 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1533
1534 retval = 0;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001535 pte_unmap_unlock(pte, ptl);
1536 return retval;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001537out_unlock:
1538 pte_unmap_unlock(pte, ptl);
1539out:
1540 return retval;
1541}
1542
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001543/**
1544 * vm_insert_page - insert single page into user vma
1545 * @vma: user vma to map to
1546 * @addr: target user address of this page
1547 * @page: source kernel page
1548 *
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001549 * This allows drivers to insert individual pages they've allocated
1550 * into a user vma.
1551 *
1552 * The page has to be a nice clean _individual_ kernel allocation.
1553 * If you allocate a compound page, you need to have marked it as
1554 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001555 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001556 *
1557 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1558 * took an arbitrary page protection parameter. This doesn't allow
1559 * that. Your vma protection will have to be set up correctly, which
1560 * means that if you want a shared writable mapping, you'd better
1561 * ask for a shared writable mapping!
1562 *
1563 * The page does not need to be reserved.
1564 */
Nick Piggin423bad62008-04-28 02:13:01 -07001565int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1566 struct page *page)
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001567{
1568 if (addr < vma->vm_start || addr >= vma->vm_end)
1569 return -EFAULT;
1570 if (!page_count(page))
1571 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001572 vma->vm_flags |= VM_INSERTPAGE;
Nick Piggin423bad62008-04-28 02:13:01 -07001573 return insert_page(vma, addr, page, vma->vm_page_prot);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001574}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001575EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001576
Nick Piggin423bad62008-04-28 02:13:01 -07001577static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1578 unsigned long pfn, pgprot_t prot)
1579{
1580 struct mm_struct *mm = vma->vm_mm;
1581 int retval;
1582 pte_t *pte, entry;
1583 spinlock_t *ptl;
1584
1585 retval = -ENOMEM;
1586 pte = get_locked_pte(mm, addr, &ptl);
1587 if (!pte)
1588 goto out;
1589 retval = -EBUSY;
1590 if (!pte_none(*pte))
1591 goto out_unlock;
1592
1593 /* Ok, finally just insert the thing.. */
1594 entry = pte_mkspecial(pfn_pte(pfn, prot));
1595 set_pte_at(mm, addr, pte, entry);
1596 update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
1597
1598 retval = 0;
1599out_unlock:
1600 pte_unmap_unlock(pte, ptl);
1601out:
1602 return retval;
1603}
1604
Nick Piggine0dc0d82007-02-12 00:51:36 -08001605/**
1606 * vm_insert_pfn - insert single pfn into user vma
1607 * @vma: user vma to map to
1608 * @addr: target user address of this page
1609 * @pfn: source kernel pfn
1610 *
1611 * Similar to vm_inert_page, this allows drivers to insert individual pages
1612 * they've allocated into a user vma. Same comments apply.
1613 *
1614 * This function should only be called from a vm_ops->fault handler, and
1615 * in that case the handler should return NULL.
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001616 *
1617 * vma cannot be a COW mapping.
1618 *
1619 * As this is called only for pages that do not currently exist, we
1620 * do not need to flush old virtual caches or the TLB.
Nick Piggine0dc0d82007-02-12 00:51:36 -08001621 */
1622int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
Nick Piggin423bad62008-04-28 02:13:01 -07001623 unsigned long pfn)
Nick Piggine0dc0d82007-02-12 00:51:36 -08001624{
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001625 int ret;
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001626 pgprot_t pgprot = vma->vm_page_prot;
Nick Piggin7e675132008-04-28 02:13:00 -07001627 /*
1628 * Technically, architectures with pte_special can avoid all these
1629 * restrictions (same for remap_pfn_range). However we would like
1630 * consistency in testing and feature parity among all, so we should
1631 * try to keep these invariants in place for everybody.
1632 */
Jared Hulbertb379d792008-04-28 02:12:58 -07001633 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1634 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1635 (VM_PFNMAP|VM_MIXEDMAP));
1636 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1637 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
Nick Piggine0dc0d82007-02-12 00:51:36 -08001638
Nick Piggin423bad62008-04-28 02:13:01 -07001639 if (addr < vma->vm_start || addr >= vma->vm_end)
1640 return -EFAULT;
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001641 if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001642 return -EINVAL;
1643
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001644 ret = insert_pfn(vma, addr, pfn, pgprot);
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001645
1646 if (ret)
1647 untrack_pfn_vma(vma, pfn, PAGE_SIZE);
1648
1649 return ret;
Nick Piggine0dc0d82007-02-12 00:51:36 -08001650}
1651EXPORT_SYMBOL(vm_insert_pfn);
1652
Nick Piggin423bad62008-04-28 02:13:01 -07001653int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1654 unsigned long pfn)
1655{
1656 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1657
1658 if (addr < vma->vm_start || addr >= vma->vm_end)
1659 return -EFAULT;
1660
1661 /*
1662 * If we don't have pte special, then we have to use the pfn_valid()
1663 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1664 * refcount the page if pfn_valid is true (hence insert_page rather
Hugh Dickins62eede62009-09-21 17:03:34 -07001665 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1666 * without pte special, it would there be refcounted as a normal page.
Nick Piggin423bad62008-04-28 02:13:01 -07001667 */
1668 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1669 struct page *page;
1670
1671 page = pfn_to_page(pfn);
1672 return insert_page(vma, addr, page, vma->vm_page_prot);
1673 }
1674 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1675}
1676EXPORT_SYMBOL(vm_insert_mixed);
1677
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001678/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001679 * maps a range of physical memory into the requested pages. the old
1680 * mappings are removed. any references to nonexistent pages results
1681 * in null mappings (currently treated as "copy-on-access")
1682 */
1683static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1684 unsigned long addr, unsigned long end,
1685 unsigned long pfn, pgprot_t prot)
1686{
1687 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001688 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001689
Hugh Dickinsc74df322005-10-29 18:16:23 -07001690 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001691 if (!pte)
1692 return -ENOMEM;
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001693 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 do {
1695 BUG_ON(!pte_none(*pte));
Nick Piggin7e675132008-04-28 02:13:00 -07001696 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697 pfn++;
1698 } while (pte++, addr += PAGE_SIZE, addr != end);
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001699 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -07001700 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001701 return 0;
1702}
1703
1704static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1705 unsigned long addr, unsigned long end,
1706 unsigned long pfn, pgprot_t prot)
1707{
1708 pmd_t *pmd;
1709 unsigned long next;
1710
1711 pfn -= addr >> PAGE_SHIFT;
1712 pmd = pmd_alloc(mm, pud, addr);
1713 if (!pmd)
1714 return -ENOMEM;
1715 do {
1716 next = pmd_addr_end(addr, end);
1717 if (remap_pte_range(mm, pmd, addr, next,
1718 pfn + (addr >> PAGE_SHIFT), prot))
1719 return -ENOMEM;
1720 } while (pmd++, addr = next, addr != end);
1721 return 0;
1722}
1723
1724static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1725 unsigned long addr, unsigned long end,
1726 unsigned long pfn, pgprot_t prot)
1727{
1728 pud_t *pud;
1729 unsigned long next;
1730
1731 pfn -= addr >> PAGE_SHIFT;
1732 pud = pud_alloc(mm, pgd, addr);
1733 if (!pud)
1734 return -ENOMEM;
1735 do {
1736 next = pud_addr_end(addr, end);
1737 if (remap_pmd_range(mm, pud, addr, next,
1738 pfn + (addr >> PAGE_SHIFT), prot))
1739 return -ENOMEM;
1740 } while (pud++, addr = next, addr != end);
1741 return 0;
1742}
1743
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001744/**
1745 * remap_pfn_range - remap kernel memory to userspace
1746 * @vma: user vma to map to
1747 * @addr: target user address to start at
1748 * @pfn: physical address of kernel memory
1749 * @size: size of map area
1750 * @prot: page protection flags for this mapping
1751 *
1752 * Note: this is only safe if the mm semaphore is held when called.
1753 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1755 unsigned long pfn, unsigned long size, pgprot_t prot)
1756{
1757 pgd_t *pgd;
1758 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001759 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001760 struct mm_struct *mm = vma->vm_mm;
1761 int err;
1762
1763 /*
1764 * Physically remapped pages are special. Tell the
1765 * rest of the world about it:
1766 * VM_IO tells people not to look at these pages
1767 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001768 * VM_RESERVED is specified all over the place, because
1769 * in 2.4 it kept swapout's vma scan off this vma; but
1770 * in 2.6 the LRU scan won't even find its pages, so this
1771 * flag means no more than count its pages in reserved_vm,
1772 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001773 * VM_PFNMAP tells the core MM that the base pages are just
1774 * raw PFN mappings, and do not have a "struct page" associated
1775 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001776 *
1777 * There's a horrible special case to handle copy-on-write
1778 * behaviour that some programs depend on. We mark the "original"
1779 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001780 */
Pallipadi, Venkatesh4bb9c5c2009-03-12 17:45:27 -07001781 if (addr == vma->vm_start && end == vma->vm_end) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001782 vma->vm_pgoff = pfn;
Pallipadi, Venkatesh895791d2009-03-13 16:35:44 -07001783 vma->vm_flags |= VM_PFN_AT_MMAP;
Pallipadi, Venkatesh4bb9c5c2009-03-12 17:45:27 -07001784 } else if (is_cow_mapping(vma->vm_flags))
venkatesh.pallipadi@intel.com3c8bb732008-12-18 11:41:27 -08001785 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001786
Linus Torvalds6aab3412005-11-28 14:34:23 -08001787 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001789 err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
venkatesh.pallipadi@intel.coma3670612009-01-09 16:13:09 -08001790 if (err) {
1791 /*
1792 * To indicate that track_pfn related cleanup is not
1793 * needed from higher level routine calling unmap_vmas
1794 */
1795 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
Pallipadi, Venkatesh895791d2009-03-13 16:35:44 -07001796 vma->vm_flags &= ~VM_PFN_AT_MMAP;
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001797 return -EINVAL;
venkatesh.pallipadi@intel.coma3670612009-01-09 16:13:09 -08001798 }
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001799
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800 BUG_ON(addr >= end);
1801 pfn -= addr >> PAGE_SHIFT;
1802 pgd = pgd_offset(mm, addr);
1803 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001804 do {
1805 next = pgd_addr_end(addr, end);
1806 err = remap_pud_range(mm, pgd, addr, next,
1807 pfn + (addr >> PAGE_SHIFT), prot);
1808 if (err)
1809 break;
1810 } while (pgd++, addr = next, addr != end);
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001811
1812 if (err)
1813 untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
1814
Linus Torvalds1da177e2005-04-16 15:20:36 -07001815 return err;
1816}
1817EXPORT_SYMBOL(remap_pfn_range);
1818
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001819static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1820 unsigned long addr, unsigned long end,
1821 pte_fn_t fn, void *data)
1822{
1823 pte_t *pte;
1824 int err;
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001825 pgtable_t token;
Borislav Petkov94909912007-05-06 14:49:17 -07001826 spinlock_t *uninitialized_var(ptl);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001827
1828 pte = (mm == &init_mm) ?
1829 pte_alloc_kernel(pmd, addr) :
1830 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1831 if (!pte)
1832 return -ENOMEM;
1833
1834 BUG_ON(pmd_huge(*pmd));
1835
Jeremy Fitzhardinge38e0edb2009-01-06 14:39:21 -08001836 arch_enter_lazy_mmu_mode();
1837
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001838 token = pmd_pgtable(*pmd);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001839
1840 do {
Daisuke Nishimurac36987e2009-10-26 16:50:23 -07001841 err = fn(pte++, token, addr, data);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001842 if (err)
1843 break;
Daisuke Nishimurac36987e2009-10-26 16:50:23 -07001844 } while (addr += PAGE_SIZE, addr != end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001845
Jeremy Fitzhardinge38e0edb2009-01-06 14:39:21 -08001846 arch_leave_lazy_mmu_mode();
1847
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001848 if (mm != &init_mm)
1849 pte_unmap_unlock(pte-1, ptl);
1850 return err;
1851}
1852
1853static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1854 unsigned long addr, unsigned long end,
1855 pte_fn_t fn, void *data)
1856{
1857 pmd_t *pmd;
1858 unsigned long next;
1859 int err;
1860
Andi Kleenceb86872008-07-23 21:27:50 -07001861 BUG_ON(pud_huge(*pud));
1862
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001863 pmd = pmd_alloc(mm, pud, addr);
1864 if (!pmd)
1865 return -ENOMEM;
1866 do {
1867 next = pmd_addr_end(addr, end);
1868 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1869 if (err)
1870 break;
1871 } while (pmd++, addr = next, addr != end);
1872 return err;
1873}
1874
1875static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1876 unsigned long addr, unsigned long end,
1877 pte_fn_t fn, void *data)
1878{
1879 pud_t *pud;
1880 unsigned long next;
1881 int err;
1882
1883 pud = pud_alloc(mm, pgd, addr);
1884 if (!pud)
1885 return -ENOMEM;
1886 do {
1887 next = pud_addr_end(addr, end);
1888 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1889 if (err)
1890 break;
1891 } while (pud++, addr = next, addr != end);
1892 return err;
1893}
1894
1895/*
1896 * Scan a region of virtual memory, filling in page tables as necessary
1897 * and calling a provided function on each leaf page table.
1898 */
1899int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1900 unsigned long size, pte_fn_t fn, void *data)
1901{
1902 pgd_t *pgd;
1903 unsigned long next;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001904 unsigned long start = addr, end = addr + size;
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001905 int err;
1906
1907 BUG_ON(addr >= end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001908 mmu_notifier_invalidate_range_start(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001909 pgd = pgd_offset(mm, addr);
1910 do {
1911 next = pgd_addr_end(addr, end);
1912 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
1913 if (err)
1914 break;
1915 } while (pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001916 mmu_notifier_invalidate_range_end(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001917 return err;
1918}
1919EXPORT_SYMBOL_GPL(apply_to_page_range);
1920
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001922 * handle_pte_fault chooses page fault handler according to an entry
1923 * which was read non-atomically. Before making any commitment, on
1924 * those architectures or configurations (e.g. i386 with PAE) which
1925 * might give a mix of unmatched parts, do_swap_page and do_file_page
1926 * must check under lock before unmapping the pte and proceeding
1927 * (but do_wp_page is only called after already making such a check;
1928 * and do_anonymous_page and do_no_page can safely check later on).
1929 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001930static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001931 pte_t *page_table, pte_t orig_pte)
1932{
1933 int same = 1;
1934#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1935 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001936 spinlock_t *ptl = pte_lockptr(mm, pmd);
1937 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001938 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001939 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001940 }
1941#endif
1942 pte_unmap(page_table);
1943 return same;
1944}
1945
1946/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1948 * servicing faults for write access. In the normal case, do always want
1949 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1950 * that do not have writing enabled, when used by access_process_vm.
1951 */
1952static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1953{
1954 if (likely(vma->vm_flags & VM_WRITE))
1955 pte = pte_mkwrite(pte);
1956 return pte;
1957}
1958
Atsushi Nemoto9de455b2006-12-12 17:14:55 +00001959static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
Linus Torvalds6aab3412005-11-28 14:34:23 -08001960{
1961 /*
1962 * If the source page was a PFN mapping, we don't have
1963 * a "struct page" for it. We do a best-effort copy by
1964 * just copying from the original user address. If that
1965 * fails, we just zero-fill it. Live with it.
1966 */
1967 if (unlikely(!src)) {
1968 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2db2005-11-29 14:07:55 -08001969 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1970
1971 /*
1972 * This really shouldn't fail, because the page is there
1973 * in the page tables. But it might just be unreadable,
1974 * in which case we just give up and fill the result with
1975 * zeroes.
1976 */
1977 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001978 memset(kaddr, 0, PAGE_SIZE);
1979 kunmap_atomic(kaddr, KM_USER0);
Dmitriy Monakhovc4ec7b02006-10-19 23:29:08 -07001980 flush_dcache_page(dst);
Nick Piggin0ed361d2008-02-04 22:29:34 -08001981 } else
1982 copy_user_highpage(dst, src, va, vma);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001983}
1984
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001986 * This routine handles present pages, when users try to write
1987 * to a shared page. It is done by copying the page to a new address
1988 * and decrementing the shared-page counter for the old page.
1989 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990 * Note that this routine assumes that the protection checks have been
1991 * done by the caller (the low-level page fault routine in most cases).
1992 * Thus we can safely just mark it writable once we've done any necessary
1993 * COW.
1994 *
1995 * We also mark the page dirty at this point even though the page will
1996 * change only once the write actually happens. This avoids a few races,
1997 * and potentially makes it more efficient.
1998 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001999 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2000 * but allow concurrent faults), with pte both mapped and locked.
2001 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002002 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002003static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2004 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002005 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002006{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00002007 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008 pte_t entry;
Nick Piggin83c54072007-07-19 01:47:05 -07002009 int reuse = 0, ret = 0;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002010 int page_mkwrite = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002011 struct page *dirty_page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002012
Linus Torvalds6aab3412005-11-28 14:34:23 -08002013 old_page = vm_normal_page(vma, address, orig_pte);
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002014 if (!old_page) {
2015 /*
2016 * VM_MIXEDMAP !pfn_valid() case
2017 *
2018 * We should not cow pages in a shared writeable mapping.
2019 * Just mark the pages writable as we can't do any dirty
2020 * accounting on raw pfn maps.
2021 */
2022 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2023 (VM_WRITE|VM_SHARED))
2024 goto reuse;
Linus Torvalds6aab3412005-11-28 14:34:23 -08002025 goto gotten;
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002026 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002028 /*
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002029 * Take out anonymous pages first, anonymous shared vmas are
2030 * not dirty accountable.
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002031 */
Hugh Dickins9a840892009-09-21 17:02:01 -07002032 if (PageAnon(old_page) && !PageKsm(old_page)) {
Hugh Dickinsab967d82009-01-06 14:39:33 -08002033 if (!trylock_page(old_page)) {
2034 page_cache_get(old_page);
2035 pte_unmap_unlock(page_table, ptl);
2036 lock_page(old_page);
2037 page_table = pte_offset_map_lock(mm, pmd, address,
2038 &ptl);
2039 if (!pte_same(*page_table, orig_pte)) {
2040 unlock_page(old_page);
2041 page_cache_release(old_page);
2042 goto unlock;
2043 }
2044 page_cache_release(old_page);
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002045 }
Hugh Dickins7b1fe592009-01-06 14:39:34 -08002046 reuse = reuse_swap_page(old_page);
Hugh Dickinsab967d82009-01-06 14:39:33 -08002047 unlock_page(old_page);
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002048 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002049 (VM_WRITE|VM_SHARED))) {
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002050 /*
2051 * Only catch write-faults on shared writable pages,
2052 * read-only shared pages can get COWed by
2053 * get_user_pages(.write=1, .force=1).
2054 */
David Howells9637a5e2006-06-23 02:03:43 -07002055 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
Nick Pigginc2ec1752009-03-31 15:23:21 -07002056 struct vm_fault vmf;
2057 int tmp;
2058
2059 vmf.virtual_address = (void __user *)(address &
2060 PAGE_MASK);
2061 vmf.pgoff = old_page->index;
2062 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2063 vmf.page = old_page;
2064
David Howells9637a5e2006-06-23 02:03:43 -07002065 /*
2066 * Notify the address space that the page is about to
2067 * become writable so that it can prohibit this or wait
2068 * for the page to get into an appropriate state.
2069 *
2070 * We do this without the lock held, so that it can
2071 * sleep if it needs to.
2072 */
2073 page_cache_get(old_page);
2074 pte_unmap_unlock(page_table, ptl);
2075
Nick Pigginc2ec1752009-03-31 15:23:21 -07002076 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2077 if (unlikely(tmp &
2078 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2079 ret = tmp;
David Howells9637a5e2006-06-23 02:03:43 -07002080 goto unwritable_page;
Nick Pigginc2ec1752009-03-31 15:23:21 -07002081 }
Nick Pigginb827e492009-04-30 15:08:16 -07002082 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2083 lock_page(old_page);
2084 if (!old_page->mapping) {
2085 ret = 0; /* retry the fault */
2086 unlock_page(old_page);
2087 goto unwritable_page;
2088 }
2089 } else
2090 VM_BUG_ON(!PageLocked(old_page));
David Howells9637a5e2006-06-23 02:03:43 -07002091
David Howells9637a5e2006-06-23 02:03:43 -07002092 /*
2093 * Since we dropped the lock we need to revalidate
2094 * the PTE as someone else may have changed it. If
2095 * they did, we just return, as we can count on the
2096 * MMU to tell us if they didn't also make it writable.
2097 */
2098 page_table = pte_offset_map_lock(mm, pmd, address,
2099 &ptl);
Nick Pigginb827e492009-04-30 15:08:16 -07002100 if (!pte_same(*page_table, orig_pte)) {
2101 unlock_page(old_page);
2102 page_cache_release(old_page);
David Howells9637a5e2006-06-23 02:03:43 -07002103 goto unlock;
Nick Pigginb827e492009-04-30 15:08:16 -07002104 }
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002105
2106 page_mkwrite = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002107 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002108 dirty_page = old_page;
2109 get_page(dirty_page);
David Howells9637a5e2006-06-23 02:03:43 -07002110 reuse = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002111 }
2112
2113 if (reuse) {
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002114reuse:
David Howells9637a5e2006-06-23 02:03:43 -07002115 flush_cache_page(vma, address, pte_pfn(orig_pte));
2116 entry = pte_mkyoung(orig_pte);
2117 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
KAMEZAWA Hiroyuki954ffcb2007-10-16 01:25:44 -07002118 if (ptep_set_access_flags(vma, address, page_table, entry,1))
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07002119 update_mmu_cache(vma, address, entry);
David Howells9637a5e2006-06-23 02:03:43 -07002120 ret |= VM_FAULT_WRITE;
2121 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002122 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002123
2124 /*
2125 * Ok, we need to copy. Oh, well..
2126 */
Nick Pigginb5810032005-10-29 18:16:12 -07002127 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08002128gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002129 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130
2131 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07002132 goto oom;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002133
Hugh Dickins62eede62009-09-21 17:03:34 -07002134 if (is_zero_pfn(pte_pfn(orig_pte))) {
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002135 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2136 if (!new_page)
2137 goto oom;
2138 } else {
2139 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2140 if (!new_page)
2141 goto oom;
2142 cow_user_page(new_page, old_page, address, vma);
2143 }
2144 __SetPageUptodate(new_page);
2145
Nick Pigginb291f002008-10-18 20:26:44 -07002146 /*
2147 * Don't let another task, with possibly unlocked vma,
2148 * keep the mlocked page.
2149 */
Carsten Otteab926612009-02-04 15:12:16 -08002150 if ((vma->vm_flags & VM_LOCKED) && old_page) {
Nick Pigginb291f002008-10-18 20:26:44 -07002151 lock_page(old_page); /* for LRU manipulation */
2152 clear_page_mlock(old_page);
2153 unlock_page(old_page);
2154 }
Hugh Dickins65500d22005-10-29 18:15:59 -07002155
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002156 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002157 goto oom_free_new;
2158
Linus Torvalds1da177e2005-04-16 15:20:36 -07002159 /*
2160 * Re-check the pte - we dropped the lock
2161 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002162 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07002163 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08002164 if (old_page) {
Hugh Dickins920fc352005-11-21 21:32:17 -08002165 if (!PageAnon(old_page)) {
2166 dec_mm_counter(mm, file_rss);
2167 inc_mm_counter(mm, anon_rss);
2168 }
2169 } else
Hugh Dickins42946212005-10-29 18:16:05 -07002170 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08002171 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07002172 entry = mk_pte(new_page, vma->vm_page_prot);
2173 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Siddha, Suresh B4ce072f2006-09-29 01:58:42 -07002174 /*
2175 * Clear the pte entry and flush it first, before updating the
2176 * pte with the new entry. This will avoid a race condition
2177 * seen in the presence of one thread doing SMC and another
2178 * thread doing COW.
2179 */
Izik Eidus828502d2009-09-21 17:01:51 -07002180 ptep_clear_flush(vma, address, page_table);
Nick Piggin9617d952006-01-06 00:11:12 -08002181 page_add_new_anon_rmap(new_page, vma, address);
Izik Eidus828502d2009-09-21 17:01:51 -07002182 /*
2183 * We call the notify macro here because, when using secondary
2184 * mmu page tables (such as kvm shadow page tables), we want the
2185 * new page to be mapped directly into the secondary page table.
2186 */
2187 set_pte_at_notify(mm, address, page_table, entry);
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002188 update_mmu_cache(vma, address, entry);
Nick Piggin945754a2008-06-23 14:30:30 +02002189 if (old_page) {
2190 /*
2191 * Only after switching the pte to the new page may
2192 * we remove the mapcount here. Otherwise another
2193 * process may come and find the rmap count decremented
2194 * before the pte is switched to the new page, and
2195 * "reuse" the old page writing into it while our pte
2196 * here still points into it and can be read by other
2197 * threads.
2198 *
2199 * The critical issue is to order this
2200 * page_remove_rmap with the ptp_clear_flush above.
2201 * Those stores are ordered by (if nothing else,)
2202 * the barrier present in the atomic_add_negative
2203 * in page_remove_rmap.
2204 *
2205 * Then the TLB flush in ptep_clear_flush ensures that
2206 * no process can access the old page before the
2207 * decremented mapcount is visible. And the old page
2208 * cannot be reused until after the decremented
2209 * mapcount is visible. So transitively, TLBs to
2210 * old page will be flushed before it can be reused.
2211 */
Hugh Dickinsedc315f2009-01-06 14:40:11 -08002212 page_remove_rmap(old_page);
Nick Piggin945754a2008-06-23 14:30:30 +02002213 }
2214
Linus Torvalds1da177e2005-04-16 15:20:36 -07002215 /* Free the old page.. */
2216 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002217 ret |= VM_FAULT_WRITE;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002218 } else
2219 mem_cgroup_uncharge_page(new_page);
2220
Hugh Dickins920fc352005-11-21 21:32:17 -08002221 if (new_page)
2222 page_cache_release(new_page);
2223 if (old_page)
2224 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002225unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002226 pte_unmap_unlock(page_table, ptl);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002227 if (dirty_page) {
Nick Piggin79352892007-07-19 01:47:22 -07002228 /*
2229 * Yes, Virginia, this is actually required to prevent a race
2230 * with clear_page_dirty_for_io() from clearing the page dirty
2231 * bit after it clear all dirty ptes, but before a racing
2232 * do_wp_page installs a dirty pte.
2233 *
2234 * do_no_page is protected similarly.
2235 */
Nick Pigginb827e492009-04-30 15:08:16 -07002236 if (!page_mkwrite) {
2237 wait_on_page_locked(dirty_page);
2238 set_page_dirty_balance(dirty_page, page_mkwrite);
2239 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002240 put_page(dirty_page);
Nick Pigginb827e492009-04-30 15:08:16 -07002241 if (page_mkwrite) {
2242 struct address_space *mapping = dirty_page->mapping;
2243
2244 set_page_dirty(dirty_page);
2245 unlock_page(dirty_page);
2246 page_cache_release(dirty_page);
2247 if (mapping) {
2248 /*
2249 * Some device drivers do not set page.mapping
2250 * but still dirty their pages
2251 */
2252 balance_dirty_pages_ratelimited(mapping);
2253 }
2254 }
2255
2256 /* file_update_time outside page_lock */
2257 if (vma->vm_file)
2258 file_update_time(vma->vm_file);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002259 }
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002260 return ret;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002261oom_free_new:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002262 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002263oom:
Nick Pigginb827e492009-04-30 15:08:16 -07002264 if (old_page) {
2265 if (page_mkwrite) {
2266 unlock_page(old_page);
2267 page_cache_release(old_page);
2268 }
Hugh Dickins920fc352005-11-21 21:32:17 -08002269 page_cache_release(old_page);
Nick Pigginb827e492009-04-30 15:08:16 -07002270 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002271 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07002272
2273unwritable_page:
2274 page_cache_release(old_page);
Nick Pigginc2ec1752009-03-31 15:23:21 -07002275 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276}
2277
2278/*
2279 * Helper functions for unmap_mapping_range().
2280 *
2281 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2282 *
2283 * We have to restart searching the prio_tree whenever we drop the lock,
2284 * since the iterator is only valid while the lock is held, and anyway
2285 * a later vma might be split and reinserted earlier while lock dropped.
2286 *
2287 * The list of nonlinear vmas could be handled more efficiently, using
2288 * a placeholder, but handle it in the same way until a need is shown.
2289 * It is important to search the prio_tree before nonlinear list: a vma
2290 * may become nonlinear and be shifted from prio_tree to nonlinear list
2291 * while the lock is dropped; but never shifted from list to prio_tree.
2292 *
2293 * In order to make forward progress despite restarting the search,
2294 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2295 * quickly skip it next time around. Since the prio_tree search only
2296 * shows us those vmas affected by unmapping the range in question, we
2297 * can't efficiently keep all vmas in step with mapping->truncate_count:
2298 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2299 * mapping->truncate_count and vma->vm_truncate_count are protected by
2300 * i_mmap_lock.
2301 *
2302 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07002303 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002304 * and restart from that address when we reach that vma again. It might
2305 * have been split or merged, shrunk or extended, but never shifted: so
2306 * restart_addr remains valid so long as it remains in the vma's range.
2307 * unmap_mapping_range forces truncate_count to leap over page-aligned
2308 * values so we can save vma's restart_addr in its truncate_count field.
2309 */
2310#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2311
2312static void reset_vma_truncate_counts(struct address_space *mapping)
2313{
2314 struct vm_area_struct *vma;
2315 struct prio_tree_iter iter;
2316
2317 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2318 vma->vm_truncate_count = 0;
2319 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2320 vma->vm_truncate_count = 0;
2321}
2322
2323static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2324 unsigned long start_addr, unsigned long end_addr,
2325 struct zap_details *details)
2326{
2327 unsigned long restart_addr;
2328 int need_break;
2329
Nick Piggind00806b2007-07-19 01:46:57 -07002330 /*
2331 * files that support invalidating or truncating portions of the
Nick Piggind0217ac2007-07-19 01:47:03 -07002332 * file from under mmaped areas must have their ->fault function
Nick Piggin83c54072007-07-19 01:47:05 -07002333 * return a locked page (and set VM_FAULT_LOCKED in the return).
2334 * This provides synchronisation against concurrent unmapping here.
Nick Piggind00806b2007-07-19 01:46:57 -07002335 */
Nick Piggind00806b2007-07-19 01:46:57 -07002336
Linus Torvalds1da177e2005-04-16 15:20:36 -07002337again:
2338 restart_addr = vma->vm_truncate_count;
2339 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2340 start_addr = restart_addr;
2341 if (start_addr >= end_addr) {
2342 /* Top of vma has been split off since last time */
2343 vma->vm_truncate_count = details->truncate_count;
2344 return 0;
2345 }
2346 }
2347
Hugh Dickinsee39b372005-04-19 13:29:15 -07002348 restart_addr = zap_page_range(vma, start_addr,
2349 end_addr - start_addr, details);
Nick Piggin95c354f2008-01-30 13:31:20 +01002350 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002351
Hugh Dickinsee39b372005-04-19 13:29:15 -07002352 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002353 /* We have now completed this vma: mark it so */
2354 vma->vm_truncate_count = details->truncate_count;
2355 if (!need_break)
2356 return 0;
2357 } else {
2358 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07002359 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002360 if (!need_break)
2361 goto again;
2362 }
2363
2364 spin_unlock(details->i_mmap_lock);
2365 cond_resched();
2366 spin_lock(details->i_mmap_lock);
2367 return -EINTR;
2368}
2369
2370static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2371 struct zap_details *details)
2372{
2373 struct vm_area_struct *vma;
2374 struct prio_tree_iter iter;
2375 pgoff_t vba, vea, zba, zea;
2376
2377restart:
2378 vma_prio_tree_foreach(vma, &iter, root,
2379 details->first_index, details->last_index) {
2380 /* Skip quickly over those we have already dealt with */
2381 if (vma->vm_truncate_count == details->truncate_count)
2382 continue;
2383
2384 vba = vma->vm_pgoff;
2385 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2386 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2387 zba = details->first_index;
2388 if (zba < vba)
2389 zba = vba;
2390 zea = details->last_index;
2391 if (zea > vea)
2392 zea = vea;
2393
2394 if (unmap_mapping_range_vma(vma,
2395 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2396 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2397 details) < 0)
2398 goto restart;
2399 }
2400}
2401
2402static inline void unmap_mapping_range_list(struct list_head *head,
2403 struct zap_details *details)
2404{
2405 struct vm_area_struct *vma;
2406
2407 /*
2408 * In nonlinear VMAs there is no correspondence between virtual address
2409 * offset and file offset. So we must perform an exhaustive search
2410 * across *all* the pages in each nonlinear VMA, not just the pages
2411 * whose virtual address lies outside the file truncation point.
2412 */
2413restart:
2414 list_for_each_entry(vma, head, shared.vm_set.list) {
2415 /* Skip quickly over those we have already dealt with */
2416 if (vma->vm_truncate_count == details->truncate_count)
2417 continue;
2418 details->nonlinear_vma = vma;
2419 if (unmap_mapping_range_vma(vma, vma->vm_start,
2420 vma->vm_end, details) < 0)
2421 goto restart;
2422 }
2423}
2424
2425/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08002426 * unmap_mapping_range - unmap the portion of all mmaps in the specified address_space corresponding to the specified page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07002427 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002428 * @holebegin: byte in first page to unmap, relative to the start of
2429 * the underlying file. This will be rounded down to a PAGE_SIZE
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +10002430 * boundary. Note that this is different from truncate_pagecache(), which
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431 * must keep the partial page. In contrast, we must get rid of
2432 * partial pages.
2433 * @holelen: size of prospective hole in bytes. This will be rounded
2434 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2435 * end of the file.
2436 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2437 * but 0 when invalidating pagecache, don't throw away private data.
2438 */
2439void unmap_mapping_range(struct address_space *mapping,
2440 loff_t const holebegin, loff_t const holelen, int even_cows)
2441{
2442 struct zap_details details;
2443 pgoff_t hba = holebegin >> PAGE_SHIFT;
2444 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2445
2446 /* Check for overflow. */
2447 if (sizeof(holelen) > sizeof(hlen)) {
2448 long long holeend =
2449 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2450 if (holeend & ~(long long)ULONG_MAX)
2451 hlen = ULONG_MAX - hba + 1;
2452 }
2453
2454 details.check_mapping = even_cows? NULL: mapping;
2455 details.nonlinear_vma = NULL;
2456 details.first_index = hba;
2457 details.last_index = hba + hlen - 1;
2458 if (details.last_index < details.first_index)
2459 details.last_index = ULONG_MAX;
2460 details.i_mmap_lock = &mapping->i_mmap_lock;
2461
2462 spin_lock(&mapping->i_mmap_lock);
2463
Nick Piggind00806b2007-07-19 01:46:57 -07002464 /* Protect against endless unmapping loops */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002465 mapping->truncate_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002466 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2467 if (mapping->truncate_count == 0)
2468 reset_vma_truncate_counts(mapping);
2469 mapping->truncate_count++;
2470 }
2471 details.truncate_count = mapping->truncate_count;
2472
2473 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2474 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2475 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2476 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2477 spin_unlock(&mapping->i_mmap_lock);
2478}
2479EXPORT_SYMBOL(unmap_mapping_range);
2480
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002481int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2482{
2483 struct address_space *mapping = inode->i_mapping;
2484
2485 /*
2486 * If the underlying filesystem is not going to provide
2487 * a way to truncate a range of blocks (punch a hole) -
2488 * we should return failure right now.
2489 */
Al Viroacfa4382008-12-04 10:06:33 -05002490 if (!inode->i_op->truncate_range)
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002491 return -ENOSYS;
2492
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002493 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002494 down_write(&inode->i_alloc_sem);
2495 unmap_mapping_range(mapping, offset, (end - offset), 1);
2496 truncate_inode_pages_range(mapping, offset, end);
Nick Piggind00806b2007-07-19 01:46:57 -07002497 unmap_mapping_range(mapping, offset, (end - offset), 1);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002498 inode->i_op->truncate_range(inode, offset, end);
2499 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002500 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002501
2502 return 0;
2503}
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002504
Linus Torvalds1da177e2005-04-16 15:20:36 -07002505/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002506 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2507 * but allow concurrent faults), and pte mapped but not yet locked.
2508 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002509 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002510static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2511 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002512 unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002513{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002514 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002515 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07002516 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002517 pte_t pte;
KAMEZAWA Hiroyuki7a81b882009-01-07 18:07:48 -08002518 struct mem_cgroup *ptr = NULL;
Nick Piggin83c54072007-07-19 01:47:05 -07002519 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002520
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002521 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002522 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07002523
2524 entry = pte_to_swp_entry(orig_pte);
Andi Kleend1737fd2009-09-16 11:50:06 +02002525 if (unlikely(non_swap_entry(entry))) {
2526 if (is_migration_entry(entry)) {
2527 migration_entry_wait(mm, pmd, address);
2528 } else if (is_hwpoison_entry(entry)) {
2529 ret = VM_FAULT_HWPOISON;
2530 } else {
2531 print_bad_pte(vma, address, orig_pte, NULL);
Hugh Dickinsd99be1a2009-12-14 17:59:04 -08002532 ret = VM_FAULT_SIGBUS;
Andi Kleend1737fd2009-09-16 11:50:06 +02002533 }
Christoph Lameter06972122006-06-23 02:03:35 -07002534 goto out;
2535 }
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002536 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002537 page = lookup_swap_cache(entry);
2538 if (!page) {
Hugh Dickinsa5c9b692009-06-23 12:36:58 -07002539 grab_swap_token(mm); /* Contend for token _before_ read-in */
Hugh Dickins02098fe2008-02-04 22:28:42 -08002540 page = swapin_readahead(entry,
2541 GFP_HIGHUSER_MOVABLE, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002542 if (!page) {
2543 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002544 * Back out if somebody else faulted in this pte
2545 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002546 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002547 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002548 if (likely(pte_same(*page_table, orig_pte)))
2549 ret = VM_FAULT_OOM;
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002550 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Hugh Dickins65500d22005-10-29 18:15:59 -07002551 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002552 }
2553
2554 /* Had to read the page from swap area: Major fault */
2555 ret = VM_FAULT_MAJOR;
Christoph Lameterf8891e52006-06-30 01:55:45 -07002556 count_vm_event(PGMAJFAULT);
Andi Kleend1737fd2009-09-16 11:50:06 +02002557 } else if (PageHWPoison(page)) {
2558 ret = VM_FAULT_HWPOISON;
2559 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Andi Kleen4779cb32009-10-14 01:51:41 +02002560 goto out_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002561 }
2562
Linus Torvalds1da177e2005-04-16 15:20:36 -07002563 lock_page(page);
Balbir Singh20a10222007-11-14 17:00:33 -08002564 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002565
Hugh Dickins5ad64682009-12-14 17:59:24 -08002566 page = ksm_might_need_to_copy(page, vma, address);
2567 if (!page) {
2568 ret = VM_FAULT_OOM;
2569 goto out;
2570 }
2571
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002572 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
KAMEZAWA Hiroyuki073e5872008-10-18 20:28:08 -07002573 ret = VM_FAULT_OOM;
Johannes Weinerbc43f752009-04-30 15:08:08 -07002574 goto out_page;
KAMEZAWA Hiroyuki073e5872008-10-18 20:28:08 -07002575 }
2576
Linus Torvalds1da177e2005-04-16 15:20:36 -07002577 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002578 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002579 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002580 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07002581 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07002582 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002583
2584 if (unlikely(!PageUptodate(page))) {
2585 ret = VM_FAULT_SIGBUS;
2586 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002587 }
2588
KAMEZAWA Hiroyuki8c7c6e32009-01-07 18:08:00 -08002589 /*
2590 * The page isn't present yet, go ahead with the fault.
2591 *
2592 * Be careful about the sequence of operations here.
2593 * To get its accounting right, reuse_swap_page() must be called
2594 * while the page is counted on swap but not yet in mapcount i.e.
2595 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2596 * must be called after the swap_free(), or it will never succeed.
KAMEZAWA Hiroyuki03f3c432009-01-07 18:08:31 -08002597 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2598 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2599 * in page->private. In this case, a record in swap_cgroup is silently
2600 * discarded at swap_free().
KAMEZAWA Hiroyuki8c7c6e32009-01-07 18:08:00 -08002601 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002602
Hugh Dickins42946212005-10-29 18:16:05 -07002603 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002604 pte = mk_pte(page, vma->vm_page_prot);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002605 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002607 flags &= ~FAULT_FLAG_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002608 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002609 flush_icache_page(vma, page);
2610 set_pte_at(mm, address, page_table, pte);
2611 page_add_anon_rmap(page, vma, address);
KAMEZAWA Hiroyuki03f3c432009-01-07 18:08:31 -08002612 /* It's better to call commit-charge after rmap is established */
2613 mem_cgroup_commit_charge_swapin(page, ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002614
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002615 swap_free(entry);
Nick Pigginb291f002008-10-18 20:26:44 -07002616 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -08002617 try_to_free_swap(page);
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002618 unlock_page(page);
2619
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002620 if (flags & FAULT_FLAG_WRITE) {
Hugh Dickins61469f12008-03-04 14:29:04 -08002621 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2622 if (ret & VM_FAULT_ERROR)
2623 ret &= VM_FAULT_ERROR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002624 goto out;
2625 }
2626
2627 /* No need to invalidate - it was non-present before */
2628 update_mmu_cache(vma, address, pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07002629unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002630 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631out:
2632 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002633out_nomap:
KAMEZAWA Hiroyuki7a81b882009-01-07 18:07:48 -08002634 mem_cgroup_cancel_charge_swapin(ptr);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002635 pte_unmap_unlock(page_table, ptl);
Johannes Weinerbc43f752009-04-30 15:08:08 -07002636out_page:
Kirill Korotaevb8107482005-05-16 21:53:50 -07002637 unlock_page(page);
Andi Kleen4779cb32009-10-14 01:51:41 +02002638out_release:
Kirill Korotaevb8107482005-05-16 21:53:50 -07002639 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002640 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002641}
2642
2643/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002644 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2645 * but allow concurrent faults), and pte mapped but not yet locked.
2646 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002648static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2649 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002650 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002652 struct page *page;
2653 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002654 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002655
Hugh Dickins62eede62009-09-21 17:03:34 -07002656 if (!(flags & FAULT_FLAG_WRITE)) {
2657 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2658 vma->vm_page_prot));
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002659 ptl = pte_lockptr(mm, pmd);
2660 spin_lock(ptl);
2661 if (!pte_none(*page_table))
2662 goto unlock;
2663 goto setpte;
2664 }
2665
Nick Piggin557ed1f2007-10-16 01:24:40 -07002666 /* Allocate our own private page. */
2667 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002668
Nick Piggin557ed1f2007-10-16 01:24:40 -07002669 if (unlikely(anon_vma_prepare(vma)))
2670 goto oom;
2671 page = alloc_zeroed_user_highpage_movable(vma, address);
2672 if (!page)
2673 goto oom;
Nick Piggin0ed361d2008-02-04 22:29:34 -08002674 __SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002675
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002676 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002677 goto oom_free_page;
2678
Nick Piggin557ed1f2007-10-16 01:24:40 -07002679 entry = mk_pte(page, vma->vm_page_prot);
Hugh Dickins1ac0cb52009-09-21 17:03:29 -07002680 if (vma->vm_flags & VM_WRITE)
2681 entry = pte_mkwrite(pte_mkdirty(entry));
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002682
Nick Piggin557ed1f2007-10-16 01:24:40 -07002683 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Andrea Arcangeli1c2fb7a2009-09-21 17:02:22 -07002684 if (!pte_none(*page_table))
Nick Piggin557ed1f2007-10-16 01:24:40 -07002685 goto release;
Hugh Dickins9ba69292009-09-21 17:02:20 -07002686
Nick Piggin557ed1f2007-10-16 01:24:40 -07002687 inc_mm_counter(mm, anon_rss);
Nick Piggin557ed1f2007-10-16 01:24:40 -07002688 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002689setpte:
Hugh Dickins65500d22005-10-29 18:15:59 -07002690 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002691
2692 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002693 update_mmu_cache(vma, address, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002694unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002695 pte_unmap_unlock(page_table, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002696 return 0;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002697release:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002698 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002699 page_cache_release(page);
2700 goto unlock;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002701oom_free_page:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002702 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002703oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002704 return VM_FAULT_OOM;
2705}
2706
2707/*
Nick Piggin54cb8822007-07-19 01:46:59 -07002708 * __do_fault() tries to create a new page mapping. It aggressively
Linus Torvalds1da177e2005-04-16 15:20:36 -07002709 * tries to share with existing pages, but makes a separate copy if
Nick Piggin54cb8822007-07-19 01:46:59 -07002710 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2711 * the next page fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002712 *
2713 * As this is called only for pages that do not currently exist, we
2714 * do not need to flush old virtual caches or the TLB.
2715 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002716 * We enter with non-exclusive mmap_sem (to exclude vma changes,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002717 * but allow concurrent faults), and pte neither mapped nor locked.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002718 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002719 */
Nick Piggin54cb8822007-07-19 01:46:59 -07002720static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002721 unsigned long address, pmd_t *pmd,
Nick Piggin54cb8822007-07-19 01:46:59 -07002722 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002723{
Hugh Dickins16abfa02007-10-04 16:56:06 +01002724 pte_t *page_table;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002725 spinlock_t *ptl;
Nick Piggind0217ac2007-07-19 01:47:03 -07002726 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002727 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002728 int anon = 0;
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002729 int charged = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002730 struct page *dirty_page = NULL;
Nick Piggind0217ac2007-07-19 01:47:03 -07002731 struct vm_fault vmf;
2732 int ret;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002733 int page_mkwrite = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07002734
Nick Piggind0217ac2007-07-19 01:47:03 -07002735 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2736 vmf.pgoff = pgoff;
2737 vmf.flags = flags;
2738 vmf.page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002739
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002740 ret = vma->vm_ops->fault(vma, &vmf);
2741 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2742 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002743
Andi Kleena3b947e2009-09-16 11:50:08 +02002744 if (unlikely(PageHWPoison(vmf.page))) {
2745 if (ret & VM_FAULT_LOCKED)
2746 unlock_page(vmf.page);
2747 return VM_FAULT_HWPOISON;
2748 }
2749
Nick Piggind00806b2007-07-19 01:46:57 -07002750 /*
Nick Piggind0217ac2007-07-19 01:47:03 -07002751 * For consistency in subsequent calls, make the faulted page always
Nick Piggind00806b2007-07-19 01:46:57 -07002752 * locked.
2753 */
Nick Piggin83c54072007-07-19 01:47:05 -07002754 if (unlikely(!(ret & VM_FAULT_LOCKED)))
Nick Piggind0217ac2007-07-19 01:47:03 -07002755 lock_page(vmf.page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002756 else
Nick Piggind0217ac2007-07-19 01:47:03 -07002757 VM_BUG_ON(!PageLocked(vmf.page));
Nick Piggind00806b2007-07-19 01:46:57 -07002758
Linus Torvalds1da177e2005-04-16 15:20:36 -07002759 /*
2760 * Should we do an early C-O-W break?
2761 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002762 page = vmf.page;
Nick Piggin54cb8822007-07-19 01:46:59 -07002763 if (flags & FAULT_FLAG_WRITE) {
David Howells9637a5e2006-06-23 02:03:43 -07002764 if (!(vma->vm_flags & VM_SHARED)) {
Nick Piggin54cb8822007-07-19 01:46:59 -07002765 anon = 1;
Nick Piggind00806b2007-07-19 01:46:57 -07002766 if (unlikely(anon_vma_prepare(vma))) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002767 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002768 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002769 }
Nick Piggin83c54072007-07-19 01:47:05 -07002770 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2771 vma, address);
Nick Piggind00806b2007-07-19 01:46:57 -07002772 if (!page) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002773 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002774 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002775 }
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002776 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002777 ret = VM_FAULT_OOM;
2778 page_cache_release(page);
2779 goto out;
2780 }
2781 charged = 1;
Nick Pigginb291f002008-10-18 20:26:44 -07002782 /*
2783 * Don't let another task, with possibly unlocked vma,
2784 * keep the mlocked page.
2785 */
2786 if (vma->vm_flags & VM_LOCKED)
2787 clear_page_mlock(vmf.page);
Nick Piggind0217ac2007-07-19 01:47:03 -07002788 copy_user_highpage(page, vmf.page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002789 __SetPageUptodate(page);
David Howells9637a5e2006-06-23 02:03:43 -07002790 } else {
Nick Piggin54cb8822007-07-19 01:46:59 -07002791 /*
2792 * If the page will be shareable, see if the backing
David Howells9637a5e2006-06-23 02:03:43 -07002793 * address space wants to know that the page is about
Nick Piggin54cb8822007-07-19 01:46:59 -07002794 * to become writable
2795 */
Mark Fasheh69676142007-07-19 01:47:00 -07002796 if (vma->vm_ops->page_mkwrite) {
Nick Pigginc2ec1752009-03-31 15:23:21 -07002797 int tmp;
2798
Mark Fasheh69676142007-07-19 01:47:00 -07002799 unlock_page(page);
Nick Pigginb827e492009-04-30 15:08:16 -07002800 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
Nick Pigginc2ec1752009-03-31 15:23:21 -07002801 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2802 if (unlikely(tmp &
2803 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2804 ret = tmp;
Nick Pigginb827e492009-04-30 15:08:16 -07002805 goto unwritable_page;
Mark Fasheh69676142007-07-19 01:47:00 -07002806 }
Nick Pigginb827e492009-04-30 15:08:16 -07002807 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2808 lock_page(page);
2809 if (!page->mapping) {
2810 ret = 0; /* retry the fault */
2811 unlock_page(page);
2812 goto unwritable_page;
2813 }
2814 } else
2815 VM_BUG_ON(!PageLocked(page));
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002816 page_mkwrite = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002817 }
2818 }
Nick Piggin54cb8822007-07-19 01:46:59 -07002819
Linus Torvalds1da177e2005-04-16 15:20:36 -07002820 }
2821
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002822 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002823
2824 /*
2825 * This silly early PAGE_DIRTY setting removes a race
2826 * due to the bad i386 page protection. But it's valid
2827 * for other architectures too.
2828 *
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002829 * Note that if FAULT_FLAG_WRITE is set, we either now have
Linus Torvalds1da177e2005-04-16 15:20:36 -07002830 * an exclusive copy of the page, or this is a shared mapping,
2831 * so we can make it writable and dirty to avoid having to
2832 * handle that later.
2833 */
2834 /* Only go through if we didn't race with anybody else... */
Andrea Arcangeli1c2fb7a2009-09-21 17:02:22 -07002835 if (likely(pte_same(*page_table, orig_pte))) {
Nick Piggind00806b2007-07-19 01:46:57 -07002836 flush_icache_page(vma, page);
2837 entry = mk_pte(page, vma->vm_page_prot);
Nick Piggin54cb8822007-07-19 01:46:59 -07002838 if (flags & FAULT_FLAG_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002839 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002840 if (anon) {
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002841 inc_mm_counter(mm, anon_rss);
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002842 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002843 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002844 inc_mm_counter(mm, file_rss);
Nick Piggind00806b2007-07-19 01:46:57 -07002845 page_add_file_rmap(page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002846 if (flags & FAULT_FLAG_WRITE) {
Nick Piggind00806b2007-07-19 01:46:57 -07002847 dirty_page = page;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002848 get_page(dirty_page);
2849 }
Hugh Dickins42946212005-10-29 18:16:05 -07002850 }
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002851 set_pte_at(mm, address, page_table, entry);
Nick Piggind00806b2007-07-19 01:46:57 -07002852
2853 /* no need to invalidate: a not-present page won't be cached */
2854 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002855 } else {
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002856 if (charged)
2857 mem_cgroup_uncharge_page(page);
Nick Piggind00806b2007-07-19 01:46:57 -07002858 if (anon)
2859 page_cache_release(page);
2860 else
Nick Piggin54cb8822007-07-19 01:46:59 -07002861 anon = 1; /* no anon but release faulted_page */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002862 }
2863
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002864 pte_unmap_unlock(page_table, ptl);
Nick Piggind00806b2007-07-19 01:46:57 -07002865
2866out:
Nick Pigginb827e492009-04-30 15:08:16 -07002867 if (dirty_page) {
2868 struct address_space *mapping = page->mapping;
2869
2870 if (set_page_dirty(dirty_page))
2871 page_mkwrite = 1;
2872 unlock_page(dirty_page);
2873 put_page(dirty_page);
2874 if (page_mkwrite && mapping) {
2875 /*
2876 * Some device drivers do not set page.mapping but still
2877 * dirty their pages
2878 */
2879 balance_dirty_pages_ratelimited(mapping);
2880 }
2881
2882 /* file_update_time outside page_lock */
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03002883 if (vma->vm_file)
2884 file_update_time(vma->vm_file);
Nick Pigginb827e492009-04-30 15:08:16 -07002885 } else {
2886 unlock_page(vmf.page);
2887 if (anon)
2888 page_cache_release(vmf.page);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002889 }
Nick Piggind00806b2007-07-19 01:46:57 -07002890
Nick Piggin83c54072007-07-19 01:47:05 -07002891 return ret;
Nick Pigginb827e492009-04-30 15:08:16 -07002892
2893unwritable_page:
2894 page_cache_release(page);
2895 return ret;
Nick Piggin54cb8822007-07-19 01:46:59 -07002896}
Nick Piggind00806b2007-07-19 01:46:57 -07002897
Nick Piggin54cb8822007-07-19 01:46:59 -07002898static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2899 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002900 unsigned int flags, pte_t orig_pte)
Nick Piggin54cb8822007-07-19 01:46:59 -07002901{
2902 pgoff_t pgoff = (((address & PAGE_MASK)
Dean Nelson0da7e012007-10-16 01:24:45 -07002903 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
Nick Piggin54cb8822007-07-19 01:46:59 -07002904
Hugh Dickins16abfa02007-10-04 16:56:06 +01002905 pte_unmap(page_table);
2906 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Nick Piggin54cb8822007-07-19 01:46:59 -07002907}
2908
Jes Sorensenf4b81802006-09-27 01:50:10 -07002909/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002910 * Fault of a previously existing named mapping. Repopulate the pte
2911 * from the encoded file_pte if possible. This enables swappable
2912 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002913 *
2914 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2915 * but allow concurrent faults), and pte mapped but not yet locked.
2916 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002917 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002918static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins65500d22005-10-29 18:15:59 -07002919 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002920 unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002921{
Hugh Dickins65500d22005-10-29 18:15:59 -07002922 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002923
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002924 flags |= FAULT_FLAG_NONLINEAR;
2925
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002926 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Nick Piggin83c54072007-07-19 01:47:05 -07002927 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002928
Hugh Dickins2509ef22009-01-06 14:40:10 -08002929 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002930 /*
2931 * Page table corrupted: show pte and kill process.
2932 */
Hugh Dickins3dc14742009-01-06 14:40:08 -08002933 print_bad_pte(vma, address, orig_pte, NULL);
Hugh Dickinsd99be1a2009-12-14 17:59:04 -08002934 return VM_FAULT_SIGBUS;
Hugh Dickins65500d22005-10-29 18:15:59 -07002935 }
Hugh Dickins65500d22005-10-29 18:15:59 -07002936
2937 pgoff = pte_to_pgoff(orig_pte);
Hugh Dickins16abfa02007-10-04 16:56:06 +01002938 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002939}
2940
2941/*
2942 * These routines also need to handle stuff like marking pages dirty
2943 * and/or accessed for architectures that don't do it in hardware (most
2944 * RISC architectures). The early dirtying is also good on the i386.
2945 *
2946 * There is also a hook called "update_mmu_cache()" that architectures
2947 * with external mmu caches can use to update those (ie the Sparc or
2948 * PowerPC hashed page tables that act as extended TLBs).
2949 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002950 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2951 * but allow concurrent faults), and pte mapped but not yet locked.
2952 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002953 */
2954static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002955 struct vm_area_struct *vma, unsigned long address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002956 pte_t *pte, pmd_t *pmd, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002957{
2958 pte_t entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002959 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002960
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07002961 entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002962 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002963 if (pte_none(entry)) {
Jes Sorensenf4b81802006-09-27 01:50:10 -07002964 if (vma->vm_ops) {
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002965 if (likely(vma->vm_ops->fault))
Nick Piggin54cb8822007-07-19 01:46:59 -07002966 return do_linear_fault(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002967 pte, pmd, flags, entry);
Jes Sorensenf4b81802006-09-27 01:50:10 -07002968 }
2969 return do_anonymous_page(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002970 pte, pmd, flags);
Hugh Dickins65500d22005-10-29 18:15:59 -07002971 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002972 if (pte_file(entry))
Nick Piggind0217ac2007-07-19 01:47:03 -07002973 return do_nonlinear_fault(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002974 pte, pmd, flags, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002975 return do_swap_page(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002976 pte, pmd, flags, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002977 }
2978
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002979 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002980 spin_lock(ptl);
2981 if (unlikely(!pte_same(*pte, entry)))
2982 goto unlock;
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002983 if (flags & FAULT_FLAG_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002984 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002985 return do_wp_page(mm, vma, address,
2986 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002987 entry = pte_mkdirty(entry);
2988 }
2989 entry = pte_mkyoung(entry);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002990 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002991 update_mmu_cache(vma, address, entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002992 } else {
2993 /*
2994 * This is needed only for protection faults but the arch code
2995 * is not yet telling us if this is a protection fault or not.
2996 * This still avoids useless tlb flushes for .text page faults
2997 * with threads.
2998 */
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002999 if (flags & FAULT_FLAG_WRITE)
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07003000 flush_tlb_page(vma, address);
3001 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003002unlock:
3003 pte_unmap_unlock(pte, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07003004 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003005}
3006
3007/*
3008 * By the time we get here, we already hold the mm semaphore
3009 */
Nick Piggin83c54072007-07-19 01:47:05 -07003010int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvaldsd06063c2009-04-10 09:01:23 -07003011 unsigned long address, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003012{
3013 pgd_t *pgd;
3014 pud_t *pud;
3015 pmd_t *pmd;
3016 pte_t *pte;
3017
3018 __set_current_state(TASK_RUNNING);
3019
Christoph Lameterf8891e52006-06-30 01:55:45 -07003020 count_vm_event(PGFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003021
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01003022 if (unlikely(is_vm_hugetlb_page(vma)))
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003023 return hugetlb_fault(mm, vma, address, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003024
Linus Torvalds1da177e2005-04-16 15:20:36 -07003025 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003026 pud = pud_alloc(mm, pgd, address);
3027 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003028 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003029 pmd = pmd_alloc(mm, pud, address);
3030 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003031 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003032 pte = pte_alloc_map(mm, pmd, address);
3033 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003034 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003035
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003036 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003037}
3038
3039#ifndef __PAGETABLE_PUD_FOLDED
3040/*
3041 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07003042 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003043 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07003044int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003045{
Hugh Dickinsc74df322005-10-29 18:16:23 -07003046 pud_t *new = pud_alloc_one(mm, address);
3047 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07003048 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003049
Nick Piggin362a61a2008-05-14 06:37:36 +02003050 smp_wmb(); /* See comment in __pte_alloc */
3051
Hugh Dickins872fec12005-10-29 18:16:21 -07003052 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003053 if (pgd_present(*pgd)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003054 pud_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003055 else
3056 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07003057 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003058 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003059}
3060#endif /* __PAGETABLE_PUD_FOLDED */
3061
3062#ifndef __PAGETABLE_PMD_FOLDED
3063/*
3064 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07003065 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003066 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07003067int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003068{
Hugh Dickinsc74df322005-10-29 18:16:23 -07003069 pmd_t *new = pmd_alloc_one(mm, address);
3070 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07003071 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003072
Nick Piggin362a61a2008-05-14 06:37:36 +02003073 smp_wmb(); /* See comment in __pte_alloc */
3074
Hugh Dickins872fec12005-10-29 18:16:21 -07003075 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003076#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07003077 if (pud_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003078 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003079 else
3080 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003081#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07003082 if (pgd_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003083 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003084 else
3085 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003086#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07003087 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003088 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003089}
3090#endif /* __PAGETABLE_PMD_FOLDED */
3091
3092int make_pages_present(unsigned long addr, unsigned long end)
3093{
3094 int ret, len, write;
3095 struct vm_area_struct * vma;
3096
3097 vma = find_vma(current->mm, addr);
3098 if (!vma)
KOSAKI Motohiroa4770972008-08-04 13:41:14 -07003099 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003100 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02003101 BUG_ON(addr >= end);
3102 BUG_ON(end > vma->vm_end);
Rolf Eike Beer68e116a2007-07-15 23:38:03 -07003103 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003104 ret = get_user_pages(current, current->mm, addr,
3105 len, write, 0, NULL, NULL);
Lee Schermerhornc11d69d2008-10-18 20:26:56 -07003106 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003107 return ret;
Lee Schermerhorn9978ad52008-10-18 20:26:56 -07003108 return ret == len ? 0 : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003109}
3110
Linus Torvalds1da177e2005-04-16 15:20:36 -07003111#if !defined(__HAVE_ARCH_GATE_AREA)
3112
3113#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07003114static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003115
3116static int __init gate_vma_init(void)
3117{
3118 gate_vma.vm_mm = NULL;
3119 gate_vma.vm_start = FIXADDR_USER_START;
3120 gate_vma.vm_end = FIXADDR_USER_END;
Roland McGrathb6558c42007-01-26 00:56:47 -08003121 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3122 gate_vma.vm_page_prot = __P101;
Roland McGrathf47aef52007-01-26 00:56:49 -08003123 /*
3124 * Make sure the vDSO gets into every core dump.
3125 * Dumping its contents makes post-mortem fully interpretable later
3126 * without matching up the same kernel and hardware config to see
3127 * what PC values meant.
3128 */
3129 gate_vma.vm_flags |= VM_ALWAYSDUMP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003130 return 0;
3131}
3132__initcall(gate_vma_init);
3133#endif
3134
3135struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
3136{
3137#ifdef AT_SYSINFO_EHDR
3138 return &gate_vma;
3139#else
3140 return NULL;
3141#endif
3142}
3143
3144int in_gate_area_no_task(unsigned long addr)
3145{
3146#ifdef AT_SYSINFO_EHDR
3147 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3148 return 1;
3149#endif
3150 return 0;
3151}
3152
3153#endif /* __HAVE_ARCH_GATE_AREA */
David Howells0ec76a12006-09-27 01:50:15 -07003154
Johannes Weinerf8ad0f492009-06-16 15:32:33 -07003155static int follow_pte(struct mm_struct *mm, unsigned long address,
3156 pte_t **ptepp, spinlock_t **ptlp)
3157{
3158 pgd_t *pgd;
3159 pud_t *pud;
3160 pmd_t *pmd;
3161 pte_t *ptep;
3162
3163 pgd = pgd_offset(mm, address);
3164 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3165 goto out;
3166
3167 pud = pud_offset(pgd, address);
3168 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3169 goto out;
3170
3171 pmd = pmd_offset(pud, address);
3172 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3173 goto out;
3174
3175 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3176 if (pmd_huge(*pmd))
3177 goto out;
3178
3179 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3180 if (!ptep)
3181 goto out;
3182 if (!pte_present(*ptep))
3183 goto unlock;
3184 *ptepp = ptep;
3185 return 0;
3186unlock:
3187 pte_unmap_unlock(ptep, *ptlp);
3188out:
3189 return -EINVAL;
3190}
3191
Johannes Weiner3b6748e2009-06-16 15:32:35 -07003192/**
3193 * follow_pfn - look up PFN at a user virtual address
3194 * @vma: memory mapping
3195 * @address: user virtual address
3196 * @pfn: location to store found PFN
3197 *
3198 * Only IO mappings and raw PFN mappings are allowed.
3199 *
3200 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3201 */
3202int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3203 unsigned long *pfn)
3204{
3205 int ret = -EINVAL;
3206 spinlock_t *ptl;
3207 pte_t *ptep;
3208
3209 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3210 return ret;
3211
3212 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3213 if (ret)
3214 return ret;
3215 *pfn = pte_pfn(*ptep);
3216 pte_unmap_unlock(ptep, ptl);
3217 return 0;
3218}
3219EXPORT_SYMBOL(follow_pfn);
3220
Rik van Riel28b2ee22008-07-23 21:27:05 -07003221#ifdef CONFIG_HAVE_IOREMAP_PROT
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003222int follow_phys(struct vm_area_struct *vma,
3223 unsigned long address, unsigned int flags,
3224 unsigned long *prot, resource_size_t *phys)
Rik van Riel28b2ee22008-07-23 21:27:05 -07003225{
Johannes Weiner03668a42009-06-16 15:32:34 -07003226 int ret = -EINVAL;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003227 pte_t *ptep, pte;
3228 spinlock_t *ptl;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003229
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003230 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3231 goto out;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003232
Johannes Weiner03668a42009-06-16 15:32:34 -07003233 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003234 goto out;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003235 pte = *ptep;
Johannes Weiner03668a42009-06-16 15:32:34 -07003236
Rik van Riel28b2ee22008-07-23 21:27:05 -07003237 if ((flags & FOLL_WRITE) && !pte_write(pte))
3238 goto unlock;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003239
3240 *prot = pgprot_val(pte_pgprot(pte));
Johannes Weiner03668a42009-06-16 15:32:34 -07003241 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003242
Johannes Weiner03668a42009-06-16 15:32:34 -07003243 ret = 0;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003244unlock:
3245 pte_unmap_unlock(ptep, ptl);
3246out:
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003247 return ret;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003248}
3249
3250int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3251 void *buf, int len, int write)
3252{
3253 resource_size_t phys_addr;
3254 unsigned long prot = 0;
KOSAKI Motohiro2bc72732009-01-06 14:39:43 -08003255 void __iomem *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003256 int offset = addr & (PAGE_SIZE-1);
3257
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003258 if (follow_phys(vma, addr, write, &prot, &phys_addr))
Rik van Riel28b2ee22008-07-23 21:27:05 -07003259 return -EINVAL;
3260
3261 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3262 if (write)
3263 memcpy_toio(maddr + offset, buf, len);
3264 else
3265 memcpy_fromio(buf, maddr + offset, len);
3266 iounmap(maddr);
3267
3268 return len;
3269}
3270#endif
3271
David Howells0ec76a12006-09-27 01:50:15 -07003272/*
3273 * Access another process' address space.
3274 * Source/target buffer must be kernel space,
3275 * Do not walk the page table directly, use get_user_pages
3276 */
3277int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
3278{
3279 struct mm_struct *mm;
3280 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07003281 void *old_buf = buf;
3282
3283 mm = get_task_mm(tsk);
3284 if (!mm)
3285 return 0;
3286
3287 down_read(&mm->mmap_sem);
Simon Arlott183ff222007-10-20 01:27:18 +02003288 /* ignore errors, just check how much was successfully transferred */
David Howells0ec76a12006-09-27 01:50:15 -07003289 while (len) {
3290 int bytes, ret, offset;
3291 void *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003292 struct page *page = NULL;
David Howells0ec76a12006-09-27 01:50:15 -07003293
3294 ret = get_user_pages(tsk, mm, addr, 1,
3295 write, 1, &page, &vma);
Rik van Riel28b2ee22008-07-23 21:27:05 -07003296 if (ret <= 0) {
3297 /*
3298 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3299 * we can access using slightly different code.
3300 */
3301#ifdef CONFIG_HAVE_IOREMAP_PROT
3302 vma = find_vma(mm, addr);
3303 if (!vma)
3304 break;
3305 if (vma->vm_ops && vma->vm_ops->access)
3306 ret = vma->vm_ops->access(vma, addr, buf,
3307 len, write);
3308 if (ret <= 0)
3309#endif
3310 break;
3311 bytes = ret;
David Howells0ec76a12006-09-27 01:50:15 -07003312 } else {
Rik van Riel28b2ee22008-07-23 21:27:05 -07003313 bytes = len;
3314 offset = addr & (PAGE_SIZE-1);
3315 if (bytes > PAGE_SIZE-offset)
3316 bytes = PAGE_SIZE-offset;
3317
3318 maddr = kmap(page);
3319 if (write) {
3320 copy_to_user_page(vma, page, addr,
3321 maddr + offset, buf, bytes);
3322 set_page_dirty_lock(page);
3323 } else {
3324 copy_from_user_page(vma, page, addr,
3325 buf, maddr + offset, bytes);
3326 }
3327 kunmap(page);
3328 page_cache_release(page);
David Howells0ec76a12006-09-27 01:50:15 -07003329 }
David Howells0ec76a12006-09-27 01:50:15 -07003330 len -= bytes;
3331 buf += bytes;
3332 addr += bytes;
3333 }
3334 up_read(&mm->mmap_sem);
3335 mmput(mm);
3336
3337 return buf - old_buf;
3338}
Andi Kleen03252912008-01-30 13:33:18 +01003339
3340/*
3341 * Print the name of a VMA.
3342 */
3343void print_vma_addr(char *prefix, unsigned long ip)
3344{
3345 struct mm_struct *mm = current->mm;
3346 struct vm_area_struct *vma;
3347
Ingo Molnare8bff742008-02-13 20:21:06 +01003348 /*
3349 * Do not print if we are in atomic
3350 * contexts (in exception stacks, etc.):
3351 */
3352 if (preempt_count())
3353 return;
3354
Andi Kleen03252912008-01-30 13:33:18 +01003355 down_read(&mm->mmap_sem);
3356 vma = find_vma(mm, ip);
3357 if (vma && vma->vm_file) {
3358 struct file *f = vma->vm_file;
3359 char *buf = (char *)__get_free_page(GFP_KERNEL);
3360 if (buf) {
3361 char *p, *s;
3362
Jan Blunckcf28b482008-02-14 19:38:44 -08003363 p = d_path(&f->f_path, buf, PAGE_SIZE);
Andi Kleen03252912008-01-30 13:33:18 +01003364 if (IS_ERR(p))
3365 p = "?";
3366 s = strrchr(p, '/');
3367 if (s)
3368 p = s+1;
3369 printk("%s%s[%lx+%lx]", prefix, p,
3370 vma->vm_start,
3371 vma->vm_end - vma->vm_start);
3372 free_page((unsigned long)buf);
3373 }
3374 }
3375 up_read(&current->mm->mmap_sem);
3376}
Nick Piggin3ee1afa2008-09-10 13:37:17 +02003377
3378#ifdef CONFIG_PROVE_LOCKING
3379void might_fault(void)
3380{
Peter Zijlstra95156f02009-01-12 13:02:11 +01003381 /*
3382 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3383 * holding the mmap_sem, this is safe because kernel memory doesn't
3384 * get paged out, therefore we'll never actually fault, and the
3385 * below annotations will generate false positives.
3386 */
3387 if (segment_eq(get_fs(), KERNEL_DS))
3388 return;
3389
Nick Piggin3ee1afa2008-09-10 13:37:17 +02003390 might_sleep();
3391 /*
3392 * it would be nicer only to annotate paths which are not under
3393 * pagefault_disable, however that requires a larger audit and
3394 * providing helpers like get_user_atomic.
3395 */
3396 if (!in_atomic() && current->mm)
3397 might_lock_read(&current->mm->mmap_sem);
3398}
3399EXPORT_SYMBOL(might_fault);
3400#endif