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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
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800124
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -0800125#if defined(SPLIT_RSS_COUNTING)
126
127void __sync_task_rss_stat(struct task_struct *task, struct mm_struct *mm)
128{
129 int i;
130
131 for (i = 0; i < NR_MM_COUNTERS; i++) {
132 if (task->rss_stat.count[i]) {
133 add_mm_counter(mm, i, task->rss_stat.count[i]);
134 task->rss_stat.count[i] = 0;
135 }
136 }
137 task->rss_stat.events = 0;
138}
139
140static void add_mm_counter_fast(struct mm_struct *mm, int member, int val)
141{
142 struct task_struct *task = current;
143
144 if (likely(task->mm == mm))
145 task->rss_stat.count[member] += val;
146 else
147 add_mm_counter(mm, member, val);
148}
149#define inc_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, 1)
150#define dec_mm_counter_fast(mm, member) add_mm_counter_fast(mm, member, -1)
151
152/* sync counter once per 64 page faults */
153#define TASK_RSS_EVENTS_THRESH (64)
154static void check_sync_rss_stat(struct task_struct *task)
155{
156 if (unlikely(task != current))
157 return;
158 if (unlikely(task->rss_stat.events++ > TASK_RSS_EVENTS_THRESH))
159 __sync_task_rss_stat(task, task->mm);
160}
161
162unsigned long get_mm_counter(struct mm_struct *mm, int member)
163{
164 long val = 0;
165
166 /*
167 * Don't use task->mm here...for avoiding to use task_get_mm()..
168 * The caller must guarantee task->mm is not invalid.
169 */
170 val = atomic_long_read(&mm->rss_stat.count[member]);
171 /*
172 * counter is updated in asynchronous manner and may go to minus.
173 * But it's never be expected number for users.
174 */
175 if (val < 0)
176 return 0;
177 return (unsigned long)val;
178}
179
180void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
181{
182 __sync_task_rss_stat(task, mm);
183}
184#else
185
186#define inc_mm_counter_fast(mm, member) inc_mm_counter(mm, member)
187#define dec_mm_counter_fast(mm, member) dec_mm_counter(mm, member)
188
189static void check_sync_rss_stat(struct task_struct *task)
190{
191}
192
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -0800193#endif
194
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195/*
196 * If a p?d_bad entry is found while walking page tables, report
197 * the error, before resetting entry to p?d_none. Usually (but
198 * very seldom) called out from the p?d_none_or_clear_bad macros.
199 */
200
201void pgd_clear_bad(pgd_t *pgd)
202{
203 pgd_ERROR(*pgd);
204 pgd_clear(pgd);
205}
206
207void pud_clear_bad(pud_t *pud)
208{
209 pud_ERROR(*pud);
210 pud_clear(pud);
211}
212
213void pmd_clear_bad(pmd_t *pmd)
214{
215 pmd_ERROR(*pmd);
216 pmd_clear(pmd);
217}
218
219/*
220 * Note: this doesn't free the actual pages themselves. That
221 * has been handled earlier when unmapping all the memory regions.
222 */
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000223static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
224 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800226 pgtable_t token = pmd_pgtable(*pmd);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700227 pmd_clear(pmd);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000228 pte_free_tlb(tlb, token, addr);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700229 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230}
231
Hugh Dickinse0da3822005-04-19 13:29:15 -0700232static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
233 unsigned long addr, unsigned long end,
234 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235{
236 pmd_t *pmd;
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 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 do {
243 next = pmd_addr_end(addr, end);
244 if (pmd_none_or_clear_bad(pmd))
245 continue;
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000246 free_pte_range(tlb, pmd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247 } while (pmd++, addr = next, addr != end);
248
Hugh Dickinse0da3822005-04-19 13:29:15 -0700249 start &= PUD_MASK;
250 if (start < floor)
251 return;
252 if (ceiling) {
253 ceiling &= PUD_MASK;
254 if (!ceiling)
255 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700256 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700257 if (end - 1 > ceiling - 1)
258 return;
259
260 pmd = pmd_offset(pud, start);
261 pud_clear(pud);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000262 pmd_free_tlb(tlb, pmd, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263}
264
Hugh Dickinse0da3822005-04-19 13:29:15 -0700265static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
266 unsigned long addr, unsigned long end,
267 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268{
269 pud_t *pud;
270 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700271 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700272
Hugh Dickinse0da3822005-04-19 13:29:15 -0700273 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 do {
276 next = pud_addr_end(addr, end);
277 if (pud_none_or_clear_bad(pud))
278 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700279 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280 } while (pud++, addr = next, addr != end);
281
Hugh Dickinse0da3822005-04-19 13:29:15 -0700282 start &= PGDIR_MASK;
283 if (start < floor)
284 return;
285 if (ceiling) {
286 ceiling &= PGDIR_MASK;
287 if (!ceiling)
288 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700289 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700290 if (end - 1 > ceiling - 1)
291 return;
292
293 pud = pud_offset(pgd, start);
294 pgd_clear(pgd);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000295 pud_free_tlb(tlb, pud, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296}
297
298/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700299 * This function frees user-level page tables of a process.
300 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 * Must be called with pagetable lock held.
302 */
Jan Beulich42b77722008-07-23 21:27:10 -0700303void free_pgd_range(struct mmu_gather *tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700304 unsigned long addr, unsigned long end,
305 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306{
307 pgd_t *pgd;
308 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700309 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310
Hugh Dickinse0da3822005-04-19 13:29:15 -0700311 /*
312 * The next few lines have given us lots of grief...
313 *
314 * Why are we testing PMD* at this top level? Because often
315 * there will be no work to do at all, and we'd prefer not to
316 * go all the way down to the bottom just to discover that.
317 *
318 * Why all these "- 1"s? Because 0 represents both the bottom
319 * of the address space and the top of it (using -1 for the
320 * top wouldn't help much: the masks would do the wrong thing).
321 * The rule is that addr 0 and floor 0 refer to the bottom of
322 * the address space, but end 0 and ceiling 0 refer to the top
323 * Comparisons need to use "end - 1" and "ceiling - 1" (though
324 * that end 0 case should be mythical).
325 *
326 * Wherever addr is brought up or ceiling brought down, we must
327 * be careful to reject "the opposite 0" before it confuses the
328 * subsequent tests. But what about where end is brought down
329 * by PMD_SIZE below? no, end can't go down to 0 there.
330 *
331 * Whereas we round start (addr) and ceiling down, by different
332 * masks at different levels, in order to test whether a table
333 * now has no other vmas using it, so can be freed, we don't
334 * bother to round floor or end up - the tests don't need that.
335 */
336
337 addr &= PMD_MASK;
338 if (addr < floor) {
339 addr += PMD_SIZE;
340 if (!addr)
341 return;
342 }
343 if (ceiling) {
344 ceiling &= PMD_MASK;
345 if (!ceiling)
346 return;
347 }
348 if (end - 1 > ceiling - 1)
349 end -= PMD_SIZE;
350 if (addr > end - 1)
351 return;
352
353 start = addr;
Jan Beulich42b77722008-07-23 21:27:10 -0700354 pgd = pgd_offset(tlb->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700355 do {
356 next = pgd_addr_end(addr, end);
357 if (pgd_none_or_clear_bad(pgd))
358 continue;
Jan Beulich42b77722008-07-23 21:27:10 -0700359 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700361}
362
Jan Beulich42b77722008-07-23 21:27:10 -0700363void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700364 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700365{
366 while (vma) {
367 struct vm_area_struct *next = vma->vm_next;
368 unsigned long addr = vma->vm_start;
369
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700370 /*
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000371 * Hide vma from rmap and truncate_pagecache before freeing
372 * pgtables
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700373 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800374 unlink_anon_vmas(vma);
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700375 unlink_file_vma(vma);
376
David Gibson9da61ae2006-03-22 00:08:57 -0800377 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700378 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700379 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700380 } else {
381 /*
382 * Optimization: gather nearby vmas into one call down
383 */
384 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800385 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700386 vma = next;
387 next = vma->vm_next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800388 unlink_anon_vmas(vma);
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700389 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700390 }
391 free_pgd_range(tlb, addr, vma->vm_end,
392 floor, next? next->vm_start: ceiling);
393 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700394 vma = next;
395 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396}
397
Hugh Dickins1bb36302005-10-29 18:16:22 -0700398int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800400 pgtable_t new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700401 if (!new)
402 return -ENOMEM;
403
Nick Piggin362a61a2008-05-14 06:37:36 +0200404 /*
405 * Ensure all pte setup (eg. pte page lock and page clearing) are
406 * visible before the pte is made visible to other CPUs by being
407 * put into page tables.
408 *
409 * The other side of the story is the pointer chasing in the page
410 * table walking code (when walking the page table without locking;
411 * ie. most of the time). Fortunately, these data accesses consist
412 * of a chain of data-dependent loads, meaning most CPUs (alpha
413 * being the notable exception) will already guarantee loads are
414 * seen in-order. See the alpha page table accessors for the
415 * smp_read_barrier_depends() barriers in page table walking code.
416 */
417 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
418
Hugh Dickinsc74df322005-10-29 18:16:23 -0700419 spin_lock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800420 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 mm->nr_ptes++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422 pmd_populate(mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800423 new = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700425 spin_unlock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800426 if (new)
427 pte_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700428 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429}
430
Hugh Dickins1bb36302005-10-29 18:16:22 -0700431int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700433 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
434 if (!new)
435 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700436
Nick Piggin362a61a2008-05-14 06:37:36 +0200437 smp_wmb(); /* See comment in __pte_alloc */
438
Hugh Dickins1bb36302005-10-29 18:16:22 -0700439 spin_lock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800440 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Hugh Dickins1bb36302005-10-29 18:16:22 -0700441 pmd_populate_kernel(&init_mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800442 new = NULL;
443 }
Hugh Dickins1bb36302005-10-29 18:16:22 -0700444 spin_unlock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800445 if (new)
446 pte_free_kernel(&init_mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700447 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448}
449
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800450static inline void init_rss_vec(int *rss)
Hugh Dickinsae859762005-10-29 18:16:05 -0700451{
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800452 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
453}
454
455static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
456{
457 int i;
458
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -0800459 if (current->mm == mm)
460 sync_mm_rss(current, mm);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800461 for (i = 0; i < NR_MM_COUNTERS; i++)
462 if (rss[i])
463 add_mm_counter(mm, i, rss[i]);
Hugh Dickinsae859762005-10-29 18:16:05 -0700464}
465
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800467 * This function is called to print an error when a bad pte
468 * is found. For example, we might have a PFN-mapped pte in
469 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700470 *
471 * The calling function must still handle the error.
472 */
Hugh Dickins3dc14742009-01-06 14:40:08 -0800473static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
474 pte_t pte, struct page *page)
Nick Pigginb5810032005-10-29 18:16:12 -0700475{
Hugh Dickins3dc14742009-01-06 14:40:08 -0800476 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
477 pud_t *pud = pud_offset(pgd, addr);
478 pmd_t *pmd = pmd_offset(pud, addr);
479 struct address_space *mapping;
480 pgoff_t index;
Hugh Dickinsd936cf92009-01-06 14:40:12 -0800481 static unsigned long resume;
482 static unsigned long nr_shown;
483 static unsigned long nr_unshown;
484
485 /*
486 * Allow a burst of 60 reports, then keep quiet for that minute;
487 * or allow a steady drip of one report per second.
488 */
489 if (nr_shown == 60) {
490 if (time_before(jiffies, resume)) {
491 nr_unshown++;
492 return;
493 }
494 if (nr_unshown) {
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800495 printk(KERN_ALERT
496 "BUG: Bad page map: %lu messages suppressed\n",
Hugh Dickinsd936cf92009-01-06 14:40:12 -0800497 nr_unshown);
498 nr_unshown = 0;
499 }
500 nr_shown = 0;
501 }
502 if (nr_shown++ == 0)
503 resume = jiffies + 60 * HZ;
Hugh Dickins3dc14742009-01-06 14:40:08 -0800504
505 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
506 index = linear_page_index(vma, addr);
507
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800508 printk(KERN_ALERT
509 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800510 current->comm,
511 (long long)pte_val(pte), (long long)pmd_val(*pmd));
Wu Fengguang718a3822010-03-10 15:20:43 -0800512 if (page)
513 dump_page(page);
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800514 printk(KERN_ALERT
Hugh Dickins3dc14742009-01-06 14:40:08 -0800515 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
516 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
517 /*
518 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
519 */
520 if (vma->vm_ops)
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800521 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800522 (unsigned long)vma->vm_ops->fault);
523 if (vma->vm_file && vma->vm_file->f_op)
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800524 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800525 (unsigned long)vma->vm_file->f_op->mmap);
Nick Pigginb5810032005-10-29 18:16:12 -0700526 dump_stack();
Hugh Dickins3dc14742009-01-06 14:40:08 -0800527 add_taint(TAINT_BAD_PAGE);
Nick Pigginb5810032005-10-29 18:16:12 -0700528}
529
Linus Torvalds67121172005-12-11 20:38:17 -0800530static inline int is_cow_mapping(unsigned int flags)
531{
532 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
533}
534
Hugh Dickins62eede62009-09-21 17:03:34 -0700535#ifndef is_zero_pfn
536static inline int is_zero_pfn(unsigned long pfn)
537{
538 return pfn == zero_pfn;
539}
540#endif
541
542#ifndef my_zero_pfn
543static inline unsigned long my_zero_pfn(unsigned long addr)
544{
545 return zero_pfn;
546}
547#endif
548
Nick Pigginb5810032005-10-29 18:16:12 -0700549/*
Nick Piggin7e675132008-04-28 02:13:00 -0700550 * vm_normal_page -- This function gets the "struct page" associated with a pte.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800551 *
Nick Piggin7e675132008-04-28 02:13:00 -0700552 * "Special" mappings do not wish to be associated with a "struct page" (either
553 * it doesn't exist, or it exists but they don't want to touch it). In this
554 * case, NULL is returned here. "Normal" mappings do have a struct page.
Jared Hulbertb379d792008-04-28 02:12:58 -0700555 *
Nick Piggin7e675132008-04-28 02:13:00 -0700556 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
557 * pte bit, in which case this function is trivial. Secondly, an architecture
558 * may not have a spare pte bit, which requires a more complicated scheme,
559 * described below.
560 *
561 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
562 * special mapping (even if there are underlying and valid "struct pages").
563 * COWed pages of a VM_PFNMAP are always normal.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800564 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700565 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
566 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
Nick Piggin7e675132008-04-28 02:13:00 -0700567 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
568 * mapping will always honor the rule
Linus Torvalds6aab3412005-11-28 14:34:23 -0800569 *
570 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
571 *
Nick Piggin7e675132008-04-28 02:13:00 -0700572 * And for normal mappings this is false.
Jared Hulbertb379d792008-04-28 02:12:58 -0700573 *
Nick Piggin7e675132008-04-28 02:13:00 -0700574 * This restricts such mappings to be a linear translation from virtual address
575 * to pfn. To get around this restriction, we allow arbitrary mappings so long
576 * as the vma is not a COW mapping; in that case, we know that all ptes are
577 * special (because none can have been COWed).
Jared Hulbertb379d792008-04-28 02:12:58 -0700578 *
579 *
Nick Piggin7e675132008-04-28 02:13:00 -0700580 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
581 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700582 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
583 * page" backing, however the difference is that _all_ pages with a struct
584 * page (that is, those where pfn_valid is true) are refcounted and considered
585 * normal pages by the VM. The disadvantage is that pages are refcounted
586 * (which can be slower and simply not an option for some PFNMAP users). The
587 * advantage is that we don't have to follow the strict linearity rule of
588 * PFNMAP mappings in order to support COWable mappings.
589 *
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800590 */
Nick Piggin7e675132008-04-28 02:13:00 -0700591#ifdef __HAVE_ARCH_PTE_SPECIAL
592# define HAVE_PTE_SPECIAL 1
593#else
594# define HAVE_PTE_SPECIAL 0
595#endif
596struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
597 pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800598{
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800599 unsigned long pfn = pte_pfn(pte);
Nick Piggin7e675132008-04-28 02:13:00 -0700600
601 if (HAVE_PTE_SPECIAL) {
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800602 if (likely(!pte_special(pte)))
603 goto check_pfn;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -0700604 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
605 return NULL;
Hugh Dickins62eede62009-09-21 17:03:34 -0700606 if (!is_zero_pfn(pfn))
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800607 print_bad_pte(vma, addr, pte, NULL);
Nick Piggin7e675132008-04-28 02:13:00 -0700608 return NULL;
609 }
610
611 /* !HAVE_PTE_SPECIAL case follows: */
612
Jared Hulbertb379d792008-04-28 02:12:58 -0700613 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
614 if (vma->vm_flags & VM_MIXEDMAP) {
615 if (!pfn_valid(pfn))
616 return NULL;
617 goto out;
618 } else {
Nick Piggin7e675132008-04-28 02:13:00 -0700619 unsigned long off;
620 off = (addr - vma->vm_start) >> PAGE_SHIFT;
Jared Hulbertb379d792008-04-28 02:12:58 -0700621 if (pfn == vma->vm_pgoff + off)
622 return NULL;
623 if (!is_cow_mapping(vma->vm_flags))
624 return NULL;
625 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800626 }
627
Hugh Dickins62eede62009-09-21 17:03:34 -0700628 if (is_zero_pfn(pfn))
629 return NULL;
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800630check_pfn:
631 if (unlikely(pfn > highest_memmap_pfn)) {
632 print_bad_pte(vma, addr, pte, NULL);
633 return NULL;
634 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800635
636 /*
Nick Piggin7e675132008-04-28 02:13:00 -0700637 * NOTE! We still have PageReserved() pages in the page tables.
Nick Piggin7e675132008-04-28 02:13:00 -0700638 * eg. VDSO mappings can cause them to exist.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800639 */
Jared Hulbertb379d792008-04-28 02:12:58 -0700640out:
Linus Torvalds6aab3412005-11-28 14:34:23 -0800641 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800642}
643
644/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645 * copy one vm_area from one task to the other. Assumes the page tables
646 * already present in the new task to be cleared in the whole range
647 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 */
649
Hugh Dickins570a3352009-12-14 17:58:46 -0800650static inline unsigned long
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700652 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700653 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654{
Nick Pigginb5810032005-10-29 18:16:12 -0700655 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 pte_t pte = *src_pte;
657 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658
659 /* pte contains position in swap or file, so copy. */
660 if (unlikely(!pte_present(pte))) {
661 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700662 swp_entry_t entry = pte_to_swp_entry(pte);
663
Hugh Dickins570a3352009-12-14 17:58:46 -0800664 if (swap_duplicate(entry) < 0)
665 return entry.val;
666
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 /* make sure dst_mm is on swapoff's mmlist. */
668 if (unlikely(list_empty(&dst_mm->mmlist))) {
669 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700670 if (list_empty(&dst_mm->mmlist))
671 list_add(&dst_mm->mmlist,
672 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 spin_unlock(&mmlist_lock);
674 }
KAMEZAWA Hiroyukib084d432010-03-05 13:41:42 -0800675 if (likely(!non_swap_entry(entry)))
676 rss[MM_SWAPENTS]++;
677 else if (is_write_migration_entry(entry) &&
Christoph Lameter06972122006-06-23 02:03:35 -0700678 is_cow_mapping(vm_flags)) {
679 /*
680 * COW mappings require pages in both parent
681 * and child to be set to read.
682 */
683 make_migration_entry_read(&entry);
684 pte = swp_entry_to_pte(entry);
685 set_pte_at(src_mm, addr, src_pte, pte);
686 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700688 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 }
690
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691 /*
692 * If it's a COW mapping, write protect it both
693 * in the parent and the child
694 */
Linus Torvalds67121172005-12-11 20:38:17 -0800695 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 ptep_set_wrprotect(src_mm, addr, src_pte);
Zachary Amsden3dc90792006-09-30 23:29:30 -0700697 pte = pte_wrprotect(pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 }
699
700 /*
701 * If it's a shared mapping, mark it clean in
702 * the child
703 */
704 if (vm_flags & VM_SHARED)
705 pte = pte_mkclean(pte);
706 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800707
708 page = vm_normal_page(vma, addr, pte);
709 if (page) {
710 get_page(page);
Hugh Dickins21333b22009-09-21 17:01:59 -0700711 page_dup_rmap(page);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800712 if (PageAnon(page))
713 rss[MM_ANONPAGES]++;
714 else
715 rss[MM_FILEPAGES]++;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800716 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700717
718out_set_pte:
719 set_pte_at(dst_mm, addr, dst_pte, pte);
Hugh Dickins570a3352009-12-14 17:58:46 -0800720 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721}
722
723static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
724 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
725 unsigned long addr, unsigned long end)
726{
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700727 pte_t *orig_src_pte, *orig_dst_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700729 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700730 int progress = 0;
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800731 int rss[NR_MM_COUNTERS];
Hugh Dickins570a3352009-12-14 17:58:46 -0800732 swp_entry_t entry = (swp_entry_t){0};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733
734again:
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800735 init_rss_vec(rss);
736
Hugh Dickinsc74df322005-10-29 18:16:23 -0700737 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 if (!dst_pte)
739 return -ENOMEM;
740 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700741 src_ptl = pte_lockptr(src_mm, src_pmd);
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700742 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700743 orig_src_pte = src_pte;
744 orig_dst_pte = dst_pte;
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700745 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 do {
748 /*
749 * We are holding two locks at this point - either of them
750 * could generate latencies in another task on another CPU.
751 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700752 if (progress >= 32) {
753 progress = 0;
754 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100755 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700756 break;
757 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700758 if (pte_none(*src_pte)) {
759 progress++;
760 continue;
761 }
Hugh Dickins570a3352009-12-14 17:58:46 -0800762 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
763 vma, addr, rss);
764 if (entry.val)
765 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 progress += 8;
767 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700769 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -0700770 spin_unlock(src_ptl);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700771 pte_unmap_nested(orig_src_pte);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800772 add_mm_rss_vec(dst_mm, rss);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700773 pte_unmap_unlock(orig_dst_pte, dst_ptl);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700774 cond_resched();
Hugh Dickins570a3352009-12-14 17:58:46 -0800775
776 if (entry.val) {
777 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
778 return -ENOMEM;
779 progress = 0;
780 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 if (addr != end)
782 goto again;
783 return 0;
784}
785
786static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
787 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
788 unsigned long addr, unsigned long end)
789{
790 pmd_t *src_pmd, *dst_pmd;
791 unsigned long next;
792
793 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
794 if (!dst_pmd)
795 return -ENOMEM;
796 src_pmd = pmd_offset(src_pud, addr);
797 do {
798 next = pmd_addr_end(addr, end);
799 if (pmd_none_or_clear_bad(src_pmd))
800 continue;
801 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
802 vma, addr, next))
803 return -ENOMEM;
804 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
805 return 0;
806}
807
808static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
809 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
810 unsigned long addr, unsigned long end)
811{
812 pud_t *src_pud, *dst_pud;
813 unsigned long next;
814
815 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
816 if (!dst_pud)
817 return -ENOMEM;
818 src_pud = pud_offset(src_pgd, addr);
819 do {
820 next = pud_addr_end(addr, end);
821 if (pud_none_or_clear_bad(src_pud))
822 continue;
823 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
824 vma, addr, next))
825 return -ENOMEM;
826 } while (dst_pud++, src_pud++, addr = next, addr != end);
827 return 0;
828}
829
830int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
831 struct vm_area_struct *vma)
832{
833 pgd_t *src_pgd, *dst_pgd;
834 unsigned long next;
835 unsigned long addr = vma->vm_start;
836 unsigned long end = vma->vm_end;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700837 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838
Nick Piggind9928952005-08-28 16:49:11 +1000839 /*
840 * Don't copy ptes where a page fault will fill them correctly.
841 * Fork becomes much lighter when there are big shared or private
842 * readonly mappings. The tradeoff is that copy_page_range is more
843 * efficient than faulting.
844 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800845 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000846 if (!vma->anon_vma)
847 return 0;
848 }
849
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 if (is_vm_hugetlb_page(vma))
851 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
852
venkatesh.pallipadi@intel.com34801ba2008-12-19 13:47:29 -0800853 if (unlikely(is_pfn_mapping(vma))) {
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -0800854 /*
855 * We do not free on error cases below as remove_vma
856 * gets called on error from higher level routine
857 */
858 ret = track_pfn_vma_copy(vma);
859 if (ret)
860 return ret;
861 }
862
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700863 /*
864 * We need to invalidate the secondary MMU mappings only when
865 * there could be a permission downgrade on the ptes of the
866 * parent mm. And a permission downgrade will only happen if
867 * is_cow_mapping() returns true.
868 */
869 if (is_cow_mapping(vma->vm_flags))
870 mmu_notifier_invalidate_range_start(src_mm, addr, end);
871
872 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 dst_pgd = pgd_offset(dst_mm, addr);
874 src_pgd = pgd_offset(src_mm, addr);
875 do {
876 next = pgd_addr_end(addr, end);
877 if (pgd_none_or_clear_bad(src_pgd))
878 continue;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700879 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
880 vma, addr, next))) {
881 ret = -ENOMEM;
882 break;
883 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700885
886 if (is_cow_mapping(vma->vm_flags))
887 mmu_notifier_invalidate_range_end(src_mm,
888 vma->vm_start, end);
889 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700890}
891
Robin Holt51c6f662005-11-13 16:06:42 -0800892static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700893 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700894 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800895 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700896{
Nick Pigginb5810032005-10-29 18:16:12 -0700897 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700899 spinlock_t *ptl;
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800900 int rss[NR_MM_COUNTERS];
901
902 init_rss_vec(rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
Hugh Dickins508034a2005-10-29 18:16:30 -0700904 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700905 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 do {
907 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800908 if (pte_none(ptent)) {
909 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800911 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800912
913 (*zap_work) -= PAGE_SIZE;
914
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800916 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800917
Linus Torvalds6aab3412005-11-28 14:34:23 -0800918 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 if (unlikely(details) && page) {
920 /*
921 * unmap_shared_mapping_pages() wants to
922 * invalidate cache without truncating:
923 * unmap shared but keep private pages.
924 */
925 if (details->check_mapping &&
926 details->check_mapping != page->mapping)
927 continue;
928 /*
929 * Each page->index must be checked when
930 * invalidating or truncating nonlinear.
931 */
932 if (details->nonlinear_vma &&
933 (page->index < details->first_index ||
934 page->index > details->last_index))
935 continue;
936 }
Nick Pigginb5810032005-10-29 18:16:12 -0700937 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700938 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 tlb_remove_tlb_entry(tlb, pte, addr);
940 if (unlikely(!page))
941 continue;
942 if (unlikely(details) && details->nonlinear_vma
943 && linear_page_index(details->nonlinear_vma,
944 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700945 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700947 if (PageAnon(page))
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800948 rss[MM_ANONPAGES]--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700949 else {
950 if (pte_dirty(ptent))
951 set_page_dirty(page);
Johannes Weiner4917e5d2009-01-06 14:39:17 -0800952 if (pte_young(ptent) &&
953 likely(!VM_SequentialReadHint(vma)))
Nick Pigginbf3f3bc2009-01-06 14:38:55 -0800954 mark_page_accessed(page);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800955 rss[MM_FILEPAGES]--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700956 }
Hugh Dickinsedc315f2009-01-06 14:40:11 -0800957 page_remove_rmap(page);
Hugh Dickins3dc14742009-01-06 14:40:08 -0800958 if (unlikely(page_mapcount(page) < 0))
959 print_bad_pte(vma, addr, ptent, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 tlb_remove_page(tlb, page);
961 continue;
962 }
963 /*
964 * If details->check_mapping, we leave swap entries;
965 * if details->nonlinear_vma, we leave file entries.
966 */
967 if (unlikely(details))
968 continue;
Hugh Dickins2509ef22009-01-06 14:40:10 -0800969 if (pte_file(ptent)) {
970 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
971 print_bad_pte(vma, addr, ptent, NULL);
KAMEZAWA Hiroyukib084d432010-03-05 13:41:42 -0800972 } else {
973 swp_entry_t entry = pte_to_swp_entry(ptent);
974
975 if (!non_swap_entry(entry))
976 rss[MM_SWAPENTS]--;
977 if (unlikely(!free_swap_and_cache(entry)))
978 print_bad_pte(vma, addr, ptent, NULL);
979 }
Zachary Amsden9888a1c2006-09-30 23:29:31 -0700980 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800981 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700982
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800983 add_mm_rss_vec(mm, rss);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700984 arch_leave_lazy_mmu_mode();
Hugh Dickins508034a2005-10-29 18:16:30 -0700985 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800986
987 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988}
989
Robin Holt51c6f662005-11-13 16:06:42 -0800990static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700991 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800993 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994{
995 pmd_t *pmd;
996 unsigned long next;
997
998 pmd = pmd_offset(pud, addr);
999 do {
1000 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -08001001 if (pmd_none_or_clear_bad(pmd)) {
1002 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003 continue;
Robin Holt51c6f662005-11-13 16:06:42 -08001004 }
1005 next = zap_pte_range(tlb, vma, pmd, addr, next,
1006 zap_work, details);
1007 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
1008
1009 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010}
1011
Robin Holt51c6f662005-11-13 16:06:42 -08001012static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -07001013 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -08001015 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016{
1017 pud_t *pud;
1018 unsigned long next;
1019
1020 pud = pud_offset(pgd, addr);
1021 do {
1022 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -08001023 if (pud_none_or_clear_bad(pud)) {
1024 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025 continue;
Robin Holt51c6f662005-11-13 16:06:42 -08001026 }
1027 next = zap_pmd_range(tlb, vma, pud, addr, next,
1028 zap_work, details);
1029 } while (pud++, addr = next, (addr != end && *zap_work > 0));
1030
1031 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032}
1033
Robin Holt51c6f662005-11-13 16:06:42 -08001034static unsigned long unmap_page_range(struct mmu_gather *tlb,
1035 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001036 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -08001037 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001038{
1039 pgd_t *pgd;
1040 unsigned long next;
1041
1042 if (details && !details->check_mapping && !details->nonlinear_vma)
1043 details = NULL;
1044
1045 BUG_ON(addr >= end);
KAMEZAWA Hiroyuki569b8462009-12-15 16:47:03 -08001046 mem_cgroup_uncharge_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001047 tlb_start_vma(tlb, vma);
1048 pgd = pgd_offset(vma->vm_mm, addr);
1049 do {
1050 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -08001051 if (pgd_none_or_clear_bad(pgd)) {
1052 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001053 continue;
Robin Holt51c6f662005-11-13 16:06:42 -08001054 }
1055 next = zap_pud_range(tlb, vma, pgd, addr, next,
1056 zap_work, details);
1057 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001058 tlb_end_vma(tlb, vma);
KAMEZAWA Hiroyuki569b8462009-12-15 16:47:03 -08001059 mem_cgroup_uncharge_end();
Robin Holt51c6f662005-11-13 16:06:42 -08001060
1061 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001062}
1063
1064#ifdef CONFIG_PREEMPT
1065# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
1066#else
1067/* No preempt: go for improved straight-line efficiency */
1068# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
1069#endif
1070
1071/**
1072 * unmap_vmas - unmap a range of memory covered by a list of vma's
1073 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -07001074 * @vma: the starting vma
1075 * @start_addr: virtual address at which to start unmapping
1076 * @end_addr: virtual address at which to end unmapping
1077 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
1078 * @details: details of nonlinear truncation or shared cache invalidation
1079 *
Hugh Dickinsee39b372005-04-19 13:29:15 -07001080 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 *
Hugh Dickins508034a2005-10-29 18:16:30 -07001082 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001083 *
Hugh Dickins508034a2005-10-29 18:16:30 -07001084 * We aim to not hold locks for too long (for scheduling latency reasons).
1085 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 * return the ending mmu_gather to the caller.
1087 *
1088 * Only addresses between `start' and `end' will be unmapped.
1089 *
1090 * The VMA list must be sorted in ascending virtual address order.
1091 *
1092 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1093 * range after unmap_vmas() returns. So the only responsibility here is to
1094 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1095 * drops the lock and schedules.
1096 */
Hugh Dickins508034a2005-10-29 18:16:30 -07001097unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 struct vm_area_struct *vma, unsigned long start_addr,
1099 unsigned long end_addr, unsigned long *nr_accounted,
1100 struct zap_details *details)
1101{
Robin Holt51c6f662005-11-13 16:06:42 -08001102 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001103 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
1104 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07001105 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001106 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -07001107 int fullmm = (*tlbp)->fullmm;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001108 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001110 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001111 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112 unsigned long end;
1113
1114 start = max(vma->vm_start, start_addr);
1115 if (start >= vma->vm_end)
1116 continue;
1117 end = min(vma->vm_end, end_addr);
1118 if (end <= vma->vm_start)
1119 continue;
1120
1121 if (vma->vm_flags & VM_ACCOUNT)
1122 *nr_accounted += (end - start) >> PAGE_SHIFT;
1123
venkatesh.pallipadi@intel.com34801ba2008-12-19 13:47:29 -08001124 if (unlikely(is_pfn_mapping(vma)))
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001125 untrack_pfn_vma(vma, 0, 0);
1126
Linus Torvalds1da177e2005-04-16 15:20:36 -07001127 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 if (!tlb_start_valid) {
1129 tlb_start = start;
1130 tlb_start_valid = 1;
1131 }
1132
Robin Holt51c6f662005-11-13 16:06:42 -08001133 if (unlikely(is_vm_hugetlb_page(vma))) {
Andi Kleena137e1c2008-07-23 21:27:43 -07001134 /*
1135 * It is undesirable to test vma->vm_file as it
1136 * should be non-null for valid hugetlb area.
1137 * However, vm_file will be NULL in the error
1138 * cleanup path of do_mmap_pgoff. When
1139 * hugetlbfs ->mmap method fails,
1140 * do_mmap_pgoff() nullifies vma->vm_file
1141 * before calling this function to clean up.
1142 * Since no pte has actually been setup, it is
1143 * safe to do nothing in this case.
1144 */
1145 if (vma->vm_file) {
1146 unmap_hugepage_range(vma, start, end, NULL);
1147 zap_work -= (end - start) /
Andi Kleena5516432008-07-23 21:27:41 -07001148 pages_per_huge_page(hstate_vma(vma));
Andi Kleena137e1c2008-07-23 21:27:43 -07001149 }
1150
Robin Holt51c6f662005-11-13 16:06:42 -08001151 start = end;
1152 } else
1153 start = unmap_page_range(*tlbp, vma,
1154 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155
Robin Holt51c6f662005-11-13 16:06:42 -08001156 if (zap_work > 0) {
1157 BUG_ON(start != end);
1158 break;
1159 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001160
1161 tlb_finish_mmu(*tlbp, tlb_start, start);
1162
1163 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +01001164 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001165 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -07001166 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167 goto out;
1168 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001169 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 }
1171
Hugh Dickins508034a2005-10-29 18:16:30 -07001172 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -08001174 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001175 }
1176 }
1177out:
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001178 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001179 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180}
1181
1182/**
1183 * zap_page_range - remove user pages in a given range
1184 * @vma: vm_area_struct holding the applicable pages
1185 * @address: starting address of pages to zap
1186 * @size: number of bytes to zap
1187 * @details: details of nonlinear truncation or shared cache invalidation
1188 */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001189unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001190 unsigned long size, struct zap_details *details)
1191{
1192 struct mm_struct *mm = vma->vm_mm;
1193 struct mmu_gather *tlb;
1194 unsigned long end = address + size;
1195 unsigned long nr_accounted = 0;
1196
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001198 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001199 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001200 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
1201 if (tlb)
1202 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001203 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204}
1205
Jack Steinerc627f9c2008-07-29 22:33:53 -07001206/**
1207 * zap_vma_ptes - remove ptes mapping the vma
1208 * @vma: vm_area_struct holding ptes to be zapped
1209 * @address: starting address of pages to zap
1210 * @size: number of bytes to zap
1211 *
1212 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1213 *
1214 * The entire address range must be fully contained within the vma.
1215 *
1216 * Returns 0 if successful.
1217 */
1218int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1219 unsigned long size)
1220{
1221 if (address < vma->vm_start || address + size > vma->vm_end ||
1222 !(vma->vm_flags & VM_PFNMAP))
1223 return -1;
1224 zap_page_range(vma, address, size, NULL);
1225 return 0;
1226}
1227EXPORT_SYMBOL_GPL(zap_vma_ptes);
1228
Linus Torvalds1da177e2005-04-16 15:20:36 -07001229/*
1230 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001231 */
Linus Torvalds6aab3412005-11-28 14:34:23 -08001232struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001233 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001234{
1235 pgd_t *pgd;
1236 pud_t *pud;
1237 pmd_t *pmd;
1238 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001239 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001240 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001241 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001242
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001243 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1244 if (!IS_ERR(page)) {
1245 BUG_ON(flags & FOLL_GET);
1246 goto out;
1247 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001248
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001249 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001250 pgd = pgd_offset(mm, address);
1251 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001252 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001253
1254 pud = pud_offset(pgd, address);
Andi Kleenceb86872008-07-23 21:27:50 -07001255 if (pud_none(*pud))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001256 goto no_page_table;
Andi Kleenceb86872008-07-23 21:27:50 -07001257 if (pud_huge(*pud)) {
1258 BUG_ON(flags & FOLL_GET);
1259 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1260 goto out;
1261 }
1262 if (unlikely(pud_bad(*pud)))
1263 goto no_page_table;
1264
Linus Torvalds1da177e2005-04-16 15:20:36 -07001265 pmd = pmd_offset(pud, address);
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001266 if (pmd_none(*pmd))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001267 goto no_page_table;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001268 if (pmd_huge(*pmd)) {
1269 BUG_ON(flags & FOLL_GET);
1270 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1271 goto out;
1272 }
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001273 if (unlikely(pmd_bad(*pmd)))
1274 goto no_page_table;
1275
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001276 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001277
1278 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001279 if (!pte_present(pte))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001280 goto no_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001281 if ((flags & FOLL_WRITE) && !pte_write(pte))
1282 goto unlock;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001283
Linus Torvalds6aab3412005-11-28 14:34:23 -08001284 page = vm_normal_page(vma, address, pte);
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001285 if (unlikely(!page)) {
1286 if ((flags & FOLL_DUMP) ||
Hugh Dickins62eede62009-09-21 17:03:34 -07001287 !is_zero_pfn(pte_pfn(pte)))
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001288 goto bad_page;
1289 page = pte_page(pte);
1290 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001291
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001292 if (flags & FOLL_GET)
1293 get_page(page);
1294 if (flags & FOLL_TOUCH) {
1295 if ((flags & FOLL_WRITE) &&
1296 !pte_dirty(pte) && !PageDirty(page))
1297 set_page_dirty(page);
KOSAKI Motohirobd775c42009-03-31 15:19:37 -07001298 /*
1299 * pte_mkyoung() would be more correct here, but atomic care
1300 * is needed to avoid losing the dirty bit: it is easier to use
1301 * mark_page_accessed().
1302 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001303 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001304 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001305unlock:
1306 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001308 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001309
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001310bad_page:
1311 pte_unmap_unlock(ptep, ptl);
1312 return ERR_PTR(-EFAULT);
1313
1314no_page:
1315 pte_unmap_unlock(ptep, ptl);
1316 if (!pte_none(pte))
1317 return page;
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001318
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001319no_page_table:
1320 /*
1321 * When core dumping an enormous anonymous area that nobody
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001322 * has touched so far, we don't want to allocate unnecessary pages or
1323 * page tables. Return error instead of NULL to skip handle_mm_fault,
1324 * then get_dump_page() will return NULL to leave a hole in the dump.
1325 * But we can only make this optimization where a hole would surely
1326 * be zero-filled if handle_mm_fault() actually did handle it.
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001327 */
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001328 if ((flags & FOLL_DUMP) &&
1329 (!vma->vm_ops || !vma->vm_ops->fault))
1330 return ERR_PTR(-EFAULT);
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001331 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001332}
1333
Nick Pigginb291f002008-10-18 20:26:44 -07001334int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001335 unsigned long start, int nr_pages, unsigned int gup_flags,
Peter Zijlstra9d737772009-06-25 11:58:55 +02001336 struct page **pages, struct vm_area_struct **vmas)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001337{
1338 int i;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001339 unsigned long vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340
Peter Zijlstra9d737772009-06-25 11:58:55 +02001341 if (nr_pages <= 0)
Jonathan Corbet900cf082008-02-11 16:17:33 -07001342 return 0;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001343
1344 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1345
Linus Torvalds1da177e2005-04-16 15:20:36 -07001346 /*
1347 * Require read or write permissions.
Hugh Dickins58fa8792009-09-21 17:03:31 -07001348 * If FOLL_FORCE is set, we only require the "MAY" flags.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001349 */
Hugh Dickins58fa8792009-09-21 17:03:31 -07001350 vm_flags = (gup_flags & FOLL_WRITE) ?
1351 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1352 vm_flags &= (gup_flags & FOLL_FORCE) ?
1353 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 i = 0;
1355
1356 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001357 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001358
1359 vma = find_extend_vma(mm, start);
1360 if (!vma && in_gate_area(tsk, start)) {
1361 unsigned long pg = start & PAGE_MASK;
1362 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1363 pgd_t *pgd;
1364 pud_t *pud;
1365 pmd_t *pmd;
1366 pte_t *pte;
Nick Pigginb291f002008-10-18 20:26:44 -07001367
1368 /* user gate pages are read-only */
Hugh Dickins58fa8792009-09-21 17:03:31 -07001369 if (gup_flags & FOLL_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001370 return i ? : -EFAULT;
1371 if (pg > TASK_SIZE)
1372 pgd = pgd_offset_k(pg);
1373 else
1374 pgd = pgd_offset_gate(mm, pg);
1375 BUG_ON(pgd_none(*pgd));
1376 pud = pud_offset(pgd, pg);
1377 BUG_ON(pud_none(*pud));
1378 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001379 if (pmd_none(*pmd))
1380 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001381 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001382 if (pte_none(*pte)) {
1383 pte_unmap(pte);
1384 return i ? : -EFAULT;
1385 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001386 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001387 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001388 pages[i] = page;
1389 if (page)
1390 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391 }
1392 pte_unmap(pte);
1393 if (vmas)
1394 vmas[i] = gate_vma;
1395 i++;
1396 start += PAGE_SIZE;
Peter Zijlstra9d737772009-06-25 11:58:55 +02001397 nr_pages--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 continue;
1399 }
1400
Nick Pigginb291f002008-10-18 20:26:44 -07001401 if (!vma ||
1402 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001403 !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001404 return i ? : -EFAULT;
1405
Hugh Dickins2a15efc2009-09-21 17:03:27 -07001406 if (is_vm_hugetlb_page(vma)) {
1407 i = follow_hugetlb_page(mm, vma, pages, vmas,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001408 &start, &nr_pages, i, gup_flags);
Hugh Dickins2a15efc2009-09-21 17:03:27 -07001409 continue;
1410 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001411
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001413 struct page *page;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001414 unsigned int foll_flags = gup_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001415
Ethan Solomita462e00c2007-07-15 23:38:16 -07001416 /*
Ying Han47792802009-01-06 14:40:18 -08001417 * If we have a pending SIGKILL, don't keep faulting
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001418 * pages and potentially allocating memory.
Ethan Solomita462e00c2007-07-15 23:38:16 -07001419 */
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001420 if (unlikely(fatal_signal_pending(current)))
Ying Han47792802009-01-06 14:40:18 -08001421 return i ? i : -ERESTARTSYS;
Ethan Solomita462e00c2007-07-15 23:38:16 -07001422
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001423 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001424 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001425 int ret;
Linus Torvaldsd06063c2009-04-10 09:01:23 -07001426
Hugh Dickinsd26ed652009-06-23 13:52:49 +01001427 ret = handle_mm_fault(mm, vma, start,
1428 (foll_flags & FOLL_WRITE) ?
1429 FAULT_FLAG_WRITE : 0);
1430
Nick Piggin83c54072007-07-19 01:47:05 -07001431 if (ret & VM_FAULT_ERROR) {
1432 if (ret & VM_FAULT_OOM)
1433 return i ? i : -ENOMEM;
Andi Kleend1737fd2009-09-16 11:50:06 +02001434 if (ret &
1435 (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
Nick Piggin83c54072007-07-19 01:47:05 -07001436 return i ? i : -EFAULT;
1437 BUG();
1438 }
1439 if (ret & VM_FAULT_MAJOR)
1440 tsk->maj_flt++;
1441 else
1442 tsk->min_flt++;
1443
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001444 /*
Nick Piggin83c54072007-07-19 01:47:05 -07001445 * The VM_FAULT_WRITE bit tells us that
1446 * do_wp_page has broken COW when necessary,
1447 * even if maybe_mkwrite decided not to set
1448 * pte_write. We can thus safely do subsequent
Hugh Dickins878b63a2009-01-06 14:39:32 -08001449 * page lookups as if they were reads. But only
1450 * do so when looping for pte_write is futile:
1451 * in some cases userspace may also be wanting
1452 * to write to the gotten user page, which a
1453 * read fault here might prevent (a readonly
1454 * page might get reCOWed by userspace write).
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001455 */
Hugh Dickins878b63a2009-01-06 14:39:32 -08001456 if ((ret & VM_FAULT_WRITE) &&
1457 !(vma->vm_flags & VM_WRITE))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001458 foll_flags &= ~FOLL_WRITE;
Nick Piggin83c54072007-07-19 01:47:05 -07001459
Benjamin Herrenschmidt7f7bbbe2006-10-06 00:43:53 -07001460 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001461 }
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001462 if (IS_ERR(page))
1463 return i ? i : PTR_ERR(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001465 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001466
Russell Kinga6f36be2006-12-30 22:24:19 +00001467 flush_anon_page(vma, page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001468 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 }
1470 if (vmas)
1471 vmas[i] = vma;
1472 i++;
1473 start += PAGE_SIZE;
Peter Zijlstra9d737772009-06-25 11:58:55 +02001474 nr_pages--;
1475 } while (nr_pages && start < vma->vm_end);
1476 } while (nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001477 return i;
1478}
Nick Pigginb291f002008-10-18 20:26:44 -07001479
Nick Piggind2bf6be2009-06-16 15:31:39 -07001480/**
1481 * get_user_pages() - pin user pages in memory
1482 * @tsk: task_struct of target task
1483 * @mm: mm_struct of target mm
1484 * @start: starting user address
Peter Zijlstra9d737772009-06-25 11:58:55 +02001485 * @nr_pages: number of pages from start to pin
Nick Piggind2bf6be2009-06-16 15:31:39 -07001486 * @write: whether pages will be written to by the caller
1487 * @force: whether to force write access even if user mapping is
1488 * readonly. This will result in the page being COWed even
1489 * in MAP_SHARED mappings. You do not want this.
1490 * @pages: array that receives pointers to the pages pinned.
1491 * Should be at least nr_pages long. Or NULL, if caller
1492 * only intends to ensure the pages are faulted in.
1493 * @vmas: array of pointers to vmas corresponding to each page.
1494 * Or NULL if the caller does not require them.
1495 *
1496 * Returns number of pages pinned. This may be fewer than the number
Peter Zijlstra9d737772009-06-25 11:58:55 +02001497 * requested. If nr_pages is 0 or negative, returns 0. If no pages
Nick Piggind2bf6be2009-06-16 15:31:39 -07001498 * were pinned, returns -errno. Each page returned must be released
1499 * with a put_page() call when it is finished with. vmas will only
1500 * remain valid while mmap_sem is held.
1501 *
1502 * Must be called with mmap_sem held for read or write.
1503 *
1504 * get_user_pages walks a process's page tables and takes a reference to
1505 * each struct page that each user address corresponds to at a given
1506 * instant. That is, it takes the page that would be accessed if a user
1507 * thread accesses the given user virtual address at that instant.
1508 *
1509 * This does not guarantee that the page exists in the user mappings when
1510 * get_user_pages returns, and there may even be a completely different
1511 * page there in some cases (eg. if mmapped pagecache has been invalidated
1512 * and subsequently re faulted). However it does guarantee that the page
1513 * won't be freed completely. And mostly callers simply care that the page
1514 * contains data that was valid *at some point in time*. Typically, an IO
1515 * or similar operation cannot guarantee anything stronger anyway because
1516 * locks can't be held over the syscall boundary.
1517 *
1518 * If write=0, the page must not be written to. If the page is written to,
1519 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1520 * after the page is finished with, and before put_page is called.
1521 *
1522 * get_user_pages is typically used for fewer-copy IO operations, to get a
1523 * handle on the memory by some means other than accesses via the user virtual
1524 * addresses. The pages may be submitted for DMA to devices or accessed via
1525 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1526 * use the correct cache flushing APIs.
1527 *
1528 * See also get_user_pages_fast, for performance critical applications.
1529 */
Nick Pigginb291f002008-10-18 20:26:44 -07001530int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Peter Zijlstra9d737772009-06-25 11:58:55 +02001531 unsigned long start, int nr_pages, int write, int force,
Nick Pigginb291f002008-10-18 20:26:44 -07001532 struct page **pages, struct vm_area_struct **vmas)
1533{
Hugh Dickins58fa8792009-09-21 17:03:31 -07001534 int flags = FOLL_TOUCH;
Nick Pigginb291f002008-10-18 20:26:44 -07001535
Hugh Dickins58fa8792009-09-21 17:03:31 -07001536 if (pages)
1537 flags |= FOLL_GET;
Nick Pigginb291f002008-10-18 20:26:44 -07001538 if (write)
Hugh Dickins58fa8792009-09-21 17:03:31 -07001539 flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -07001540 if (force)
Hugh Dickins58fa8792009-09-21 17:03:31 -07001541 flags |= FOLL_FORCE;
Nick Pigginb291f002008-10-18 20:26:44 -07001542
Peter Zijlstra9d737772009-06-25 11:58:55 +02001543 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
Nick Pigginb291f002008-10-18 20:26:44 -07001544}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001545EXPORT_SYMBOL(get_user_pages);
1546
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001547/**
1548 * get_dump_page() - pin user page in memory while writing it to core dump
1549 * @addr: user address
1550 *
1551 * Returns struct page pointer of user page pinned for dump,
1552 * to be freed afterwards by page_cache_release() or put_page().
1553 *
1554 * Returns NULL on any kind of failure - a hole must then be inserted into
1555 * the corefile, to preserve alignment with its headers; and also returns
1556 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
1557 * allowing a hole to be left in the corefile to save diskspace.
1558 *
1559 * Called without mmap_sem, but after all other threads have been killed.
1560 */
1561#ifdef CONFIG_ELF_CORE
1562struct page *get_dump_page(unsigned long addr)
1563{
1564 struct vm_area_struct *vma;
1565 struct page *page;
1566
1567 if (__get_user_pages(current, current->mm, addr, 1,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001568 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001569 return NULL;
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001570 flush_cache_page(vma, addr, page_to_pfn(page));
1571 return page;
1572}
1573#endif /* CONFIG_ELF_CORE */
1574
Harvey Harrison920c7a52008-02-04 22:29:26 -08001575pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1576 spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001577{
1578 pgd_t * pgd = pgd_offset(mm, addr);
1579 pud_t * pud = pud_alloc(mm, pgd, addr);
1580 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001581 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001582 if (pmd)
1583 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1584 }
1585 return NULL;
1586}
1587
Linus Torvalds1da177e2005-04-16 15:20:36 -07001588/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001589 * This is the old fallback for page remapping.
1590 *
1591 * For historical reasons, it only allows reserved pages. Only
1592 * old drivers should use this, and they needed to mark their
1593 * pages reserved for the old functions anyway.
1594 */
Nick Piggin423bad62008-04-28 02:13:01 -07001595static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1596 struct page *page, pgprot_t prot)
Linus Torvalds238f58d2005-11-29 13:01:56 -08001597{
Nick Piggin423bad62008-04-28 02:13:01 -07001598 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001599 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001600 pte_t *pte;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001601 spinlock_t *ptl;
1602
Linus Torvalds238f58d2005-11-29 13:01:56 -08001603 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001604 if (PageAnon(page))
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07001605 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001606 retval = -ENOMEM;
1607 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001608 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001609 if (!pte)
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07001610 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001611 retval = -EBUSY;
1612 if (!pte_none(*pte))
1613 goto out_unlock;
1614
1615 /* Ok, finally just insert the thing.. */
1616 get_page(page);
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08001617 inc_mm_counter_fast(mm, MM_FILEPAGES);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001618 page_add_file_rmap(page);
1619 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1620
1621 retval = 0;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001622 pte_unmap_unlock(pte, ptl);
1623 return retval;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001624out_unlock:
1625 pte_unmap_unlock(pte, ptl);
1626out:
1627 return retval;
1628}
1629
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001630/**
1631 * vm_insert_page - insert single page into user vma
1632 * @vma: user vma to map to
1633 * @addr: target user address of this page
1634 * @page: source kernel page
1635 *
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001636 * This allows drivers to insert individual pages they've allocated
1637 * into a user vma.
1638 *
1639 * The page has to be a nice clean _individual_ kernel allocation.
1640 * If you allocate a compound page, you need to have marked it as
1641 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001642 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001643 *
1644 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1645 * took an arbitrary page protection parameter. This doesn't allow
1646 * that. Your vma protection will have to be set up correctly, which
1647 * means that if you want a shared writable mapping, you'd better
1648 * ask for a shared writable mapping!
1649 *
1650 * The page does not need to be reserved.
1651 */
Nick Piggin423bad62008-04-28 02:13:01 -07001652int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1653 struct page *page)
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001654{
1655 if (addr < vma->vm_start || addr >= vma->vm_end)
1656 return -EFAULT;
1657 if (!page_count(page))
1658 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001659 vma->vm_flags |= VM_INSERTPAGE;
Nick Piggin423bad62008-04-28 02:13:01 -07001660 return insert_page(vma, addr, page, vma->vm_page_prot);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001661}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001662EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001663
Nick Piggin423bad62008-04-28 02:13:01 -07001664static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1665 unsigned long pfn, pgprot_t prot)
1666{
1667 struct mm_struct *mm = vma->vm_mm;
1668 int retval;
1669 pte_t *pte, entry;
1670 spinlock_t *ptl;
1671
1672 retval = -ENOMEM;
1673 pte = get_locked_pte(mm, addr, &ptl);
1674 if (!pte)
1675 goto out;
1676 retval = -EBUSY;
1677 if (!pte_none(*pte))
1678 goto out_unlock;
1679
1680 /* Ok, finally just insert the thing.. */
1681 entry = pte_mkspecial(pfn_pte(pfn, prot));
1682 set_pte_at(mm, addr, pte, entry);
Russell King4b3073e2009-12-18 16:40:18 +00001683 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
Nick Piggin423bad62008-04-28 02:13:01 -07001684
1685 retval = 0;
1686out_unlock:
1687 pte_unmap_unlock(pte, ptl);
1688out:
1689 return retval;
1690}
1691
Nick Piggine0dc0d82007-02-12 00:51:36 -08001692/**
1693 * vm_insert_pfn - insert single pfn into user vma
1694 * @vma: user vma to map to
1695 * @addr: target user address of this page
1696 * @pfn: source kernel pfn
1697 *
1698 * Similar to vm_inert_page, this allows drivers to insert individual pages
1699 * they've allocated into a user vma. Same comments apply.
1700 *
1701 * This function should only be called from a vm_ops->fault handler, and
1702 * in that case the handler should return NULL.
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001703 *
1704 * vma cannot be a COW mapping.
1705 *
1706 * As this is called only for pages that do not currently exist, we
1707 * do not need to flush old virtual caches or the TLB.
Nick Piggine0dc0d82007-02-12 00:51:36 -08001708 */
1709int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
Nick Piggin423bad62008-04-28 02:13:01 -07001710 unsigned long pfn)
Nick Piggine0dc0d82007-02-12 00:51:36 -08001711{
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001712 int ret;
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001713 pgprot_t pgprot = vma->vm_page_prot;
Nick Piggin7e675132008-04-28 02:13:00 -07001714 /*
1715 * Technically, architectures with pte_special can avoid all these
1716 * restrictions (same for remap_pfn_range). However we would like
1717 * consistency in testing and feature parity among all, so we should
1718 * try to keep these invariants in place for everybody.
1719 */
Jared Hulbertb379d792008-04-28 02:12:58 -07001720 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1721 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1722 (VM_PFNMAP|VM_MIXEDMAP));
1723 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1724 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
Nick Piggine0dc0d82007-02-12 00:51:36 -08001725
Nick Piggin423bad62008-04-28 02:13:01 -07001726 if (addr < vma->vm_start || addr >= vma->vm_end)
1727 return -EFAULT;
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001728 if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001729 return -EINVAL;
1730
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001731 ret = insert_pfn(vma, addr, pfn, pgprot);
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001732
1733 if (ret)
1734 untrack_pfn_vma(vma, pfn, PAGE_SIZE);
1735
1736 return ret;
Nick Piggine0dc0d82007-02-12 00:51:36 -08001737}
1738EXPORT_SYMBOL(vm_insert_pfn);
1739
Nick Piggin423bad62008-04-28 02:13:01 -07001740int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1741 unsigned long pfn)
1742{
1743 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1744
1745 if (addr < vma->vm_start || addr >= vma->vm_end)
1746 return -EFAULT;
1747
1748 /*
1749 * If we don't have pte special, then we have to use the pfn_valid()
1750 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1751 * refcount the page if pfn_valid is true (hence insert_page rather
Hugh Dickins62eede62009-09-21 17:03:34 -07001752 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1753 * without pte special, it would there be refcounted as a normal page.
Nick Piggin423bad62008-04-28 02:13:01 -07001754 */
1755 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1756 struct page *page;
1757
1758 page = pfn_to_page(pfn);
1759 return insert_page(vma, addr, page, vma->vm_page_prot);
1760 }
1761 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1762}
1763EXPORT_SYMBOL(vm_insert_mixed);
1764
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001765/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001766 * maps a range of physical memory into the requested pages. the old
1767 * mappings are removed. any references to nonexistent pages results
1768 * in null mappings (currently treated as "copy-on-access")
1769 */
1770static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1771 unsigned long addr, unsigned long end,
1772 unsigned long pfn, pgprot_t prot)
1773{
1774 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001775 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776
Hugh Dickinsc74df322005-10-29 18:16:23 -07001777 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001778 if (!pte)
1779 return -ENOMEM;
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001780 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001781 do {
1782 BUG_ON(!pte_none(*pte));
Nick Piggin7e675132008-04-28 02:13:00 -07001783 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 pfn++;
1785 } while (pte++, addr += PAGE_SIZE, addr != end);
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001786 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -07001787 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 return 0;
1789}
1790
1791static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1792 unsigned long addr, unsigned long end,
1793 unsigned long pfn, pgprot_t prot)
1794{
1795 pmd_t *pmd;
1796 unsigned long next;
1797
1798 pfn -= addr >> PAGE_SHIFT;
1799 pmd = pmd_alloc(mm, pud, addr);
1800 if (!pmd)
1801 return -ENOMEM;
1802 do {
1803 next = pmd_addr_end(addr, end);
1804 if (remap_pte_range(mm, pmd, addr, next,
1805 pfn + (addr >> PAGE_SHIFT), prot))
1806 return -ENOMEM;
1807 } while (pmd++, addr = next, addr != end);
1808 return 0;
1809}
1810
1811static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1812 unsigned long addr, unsigned long end,
1813 unsigned long pfn, pgprot_t prot)
1814{
1815 pud_t *pud;
1816 unsigned long next;
1817
1818 pfn -= addr >> PAGE_SHIFT;
1819 pud = pud_alloc(mm, pgd, addr);
1820 if (!pud)
1821 return -ENOMEM;
1822 do {
1823 next = pud_addr_end(addr, end);
1824 if (remap_pmd_range(mm, pud, addr, next,
1825 pfn + (addr >> PAGE_SHIFT), prot))
1826 return -ENOMEM;
1827 } while (pud++, addr = next, addr != end);
1828 return 0;
1829}
1830
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001831/**
1832 * remap_pfn_range - remap kernel memory to userspace
1833 * @vma: user vma to map to
1834 * @addr: target user address to start at
1835 * @pfn: physical address of kernel memory
1836 * @size: size of map area
1837 * @prot: page protection flags for this mapping
1838 *
1839 * Note: this is only safe if the mm semaphore is held when called.
1840 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001841int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1842 unsigned long pfn, unsigned long size, pgprot_t prot)
1843{
1844 pgd_t *pgd;
1845 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001846 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847 struct mm_struct *mm = vma->vm_mm;
1848 int err;
1849
1850 /*
1851 * Physically remapped pages are special. Tell the
1852 * rest of the world about it:
1853 * VM_IO tells people not to look at these pages
1854 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001855 * VM_RESERVED is specified all over the place, because
1856 * in 2.4 it kept swapout's vma scan off this vma; but
1857 * in 2.6 the LRU scan won't even find its pages, so this
1858 * flag means no more than count its pages in reserved_vm,
1859 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001860 * VM_PFNMAP tells the core MM that the base pages are just
1861 * raw PFN mappings, and do not have a "struct page" associated
1862 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001863 *
1864 * There's a horrible special case to handle copy-on-write
1865 * behaviour that some programs depend on. We mark the "original"
1866 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 */
Pallipadi, Venkatesh4bb9c5c2009-03-12 17:45:27 -07001868 if (addr == vma->vm_start && end == vma->vm_end) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001869 vma->vm_pgoff = pfn;
Pallipadi, Venkatesh895791d2009-03-13 16:35:44 -07001870 vma->vm_flags |= VM_PFN_AT_MMAP;
Pallipadi, Venkatesh4bb9c5c2009-03-12 17:45:27 -07001871 } else if (is_cow_mapping(vma->vm_flags))
venkatesh.pallipadi@intel.com3c8bb732008-12-18 11:41:27 -08001872 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001873
Linus Torvalds6aab3412005-11-28 14:34:23 -08001874 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001876 err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
venkatesh.pallipadi@intel.coma3670612009-01-09 16:13:09 -08001877 if (err) {
1878 /*
1879 * To indicate that track_pfn related cleanup is not
1880 * needed from higher level routine calling unmap_vmas
1881 */
1882 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
Pallipadi, Venkatesh895791d2009-03-13 16:35:44 -07001883 vma->vm_flags &= ~VM_PFN_AT_MMAP;
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001884 return -EINVAL;
venkatesh.pallipadi@intel.coma3670612009-01-09 16:13:09 -08001885 }
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001886
Linus Torvalds1da177e2005-04-16 15:20:36 -07001887 BUG_ON(addr >= end);
1888 pfn -= addr >> PAGE_SHIFT;
1889 pgd = pgd_offset(mm, addr);
1890 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 do {
1892 next = pgd_addr_end(addr, end);
1893 err = remap_pud_range(mm, pgd, addr, next,
1894 pfn + (addr >> PAGE_SHIFT), prot);
1895 if (err)
1896 break;
1897 } while (pgd++, addr = next, addr != end);
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001898
1899 if (err)
1900 untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
1901
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 return err;
1903}
1904EXPORT_SYMBOL(remap_pfn_range);
1905
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001906static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1907 unsigned long addr, unsigned long end,
1908 pte_fn_t fn, void *data)
1909{
1910 pte_t *pte;
1911 int err;
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001912 pgtable_t token;
Borislav Petkov94909912007-05-06 14:49:17 -07001913 spinlock_t *uninitialized_var(ptl);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001914
1915 pte = (mm == &init_mm) ?
1916 pte_alloc_kernel(pmd, addr) :
1917 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1918 if (!pte)
1919 return -ENOMEM;
1920
1921 BUG_ON(pmd_huge(*pmd));
1922
Jeremy Fitzhardinge38e0edb2009-01-06 14:39:21 -08001923 arch_enter_lazy_mmu_mode();
1924
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001925 token = pmd_pgtable(*pmd);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001926
1927 do {
Daisuke Nishimurac36987e2009-10-26 16:50:23 -07001928 err = fn(pte++, token, addr, data);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001929 if (err)
1930 break;
Daisuke Nishimurac36987e2009-10-26 16:50:23 -07001931 } while (addr += PAGE_SIZE, addr != end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001932
Jeremy Fitzhardinge38e0edb2009-01-06 14:39:21 -08001933 arch_leave_lazy_mmu_mode();
1934
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001935 if (mm != &init_mm)
1936 pte_unmap_unlock(pte-1, ptl);
1937 return err;
1938}
1939
1940static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1941 unsigned long addr, unsigned long end,
1942 pte_fn_t fn, void *data)
1943{
1944 pmd_t *pmd;
1945 unsigned long next;
1946 int err;
1947
Andi Kleenceb86872008-07-23 21:27:50 -07001948 BUG_ON(pud_huge(*pud));
1949
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001950 pmd = pmd_alloc(mm, pud, addr);
1951 if (!pmd)
1952 return -ENOMEM;
1953 do {
1954 next = pmd_addr_end(addr, end);
1955 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1956 if (err)
1957 break;
1958 } while (pmd++, addr = next, addr != end);
1959 return err;
1960}
1961
1962static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1963 unsigned long addr, unsigned long end,
1964 pte_fn_t fn, void *data)
1965{
1966 pud_t *pud;
1967 unsigned long next;
1968 int err;
1969
1970 pud = pud_alloc(mm, pgd, addr);
1971 if (!pud)
1972 return -ENOMEM;
1973 do {
1974 next = pud_addr_end(addr, end);
1975 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1976 if (err)
1977 break;
1978 } while (pud++, addr = next, addr != end);
1979 return err;
1980}
1981
1982/*
1983 * Scan a region of virtual memory, filling in page tables as necessary
1984 * and calling a provided function on each leaf page table.
1985 */
1986int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1987 unsigned long size, pte_fn_t fn, void *data)
1988{
1989 pgd_t *pgd;
1990 unsigned long next;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001991 unsigned long start = addr, end = addr + size;
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001992 int err;
1993
1994 BUG_ON(addr >= end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001995 mmu_notifier_invalidate_range_start(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001996 pgd = pgd_offset(mm, addr);
1997 do {
1998 next = pgd_addr_end(addr, end);
1999 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2000 if (err)
2001 break;
2002 } while (pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002003 mmu_notifier_invalidate_range_end(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07002004 return err;
2005}
2006EXPORT_SYMBOL_GPL(apply_to_page_range);
2007
Linus Torvalds1da177e2005-04-16 15:20:36 -07002008/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002009 * handle_pte_fault chooses page fault handler according to an entry
2010 * which was read non-atomically. Before making any commitment, on
2011 * those architectures or configurations (e.g. i386 with PAE) which
2012 * might give a mix of unmatched parts, do_swap_page and do_file_page
2013 * must check under lock before unmapping the pte and proceeding
2014 * (but do_wp_page is only called after already making such a check;
2015 * and do_anonymous_page and do_no_page can safely check later on).
2016 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002017static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002018 pte_t *page_table, pte_t orig_pte)
2019{
2020 int same = 1;
2021#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2022 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002023 spinlock_t *ptl = pte_lockptr(mm, pmd);
2024 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002025 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002026 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002027 }
2028#endif
2029 pte_unmap(page_table);
2030 return same;
2031}
2032
2033/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
2035 * servicing faults for write access. In the normal case, do always want
2036 * pte_mkwrite. But get_user_pages can cause write faults for mappings
2037 * that do not have writing enabled, when used by access_process_vm.
2038 */
2039static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
2040{
2041 if (likely(vma->vm_flags & VM_WRITE))
2042 pte = pte_mkwrite(pte);
2043 return pte;
2044}
2045
Atsushi Nemoto9de455b2006-12-12 17:14:55 +00002046static 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 -08002047{
2048 /*
2049 * If the source page was a PFN mapping, we don't have
2050 * a "struct page" for it. We do a best-effort copy by
2051 * just copying from the original user address. If that
2052 * fails, we just zero-fill it. Live with it.
2053 */
2054 if (unlikely(!src)) {
2055 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2db2005-11-29 14:07:55 -08002056 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2057
2058 /*
2059 * This really shouldn't fail, because the page is there
2060 * in the page tables. But it might just be unreadable,
2061 * in which case we just give up and fill the result with
2062 * zeroes.
2063 */
2064 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08002065 memset(kaddr, 0, PAGE_SIZE);
2066 kunmap_atomic(kaddr, KM_USER0);
Dmitriy Monakhovc4ec7b02006-10-19 23:29:08 -07002067 flush_dcache_page(dst);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002068 } else
2069 copy_user_highpage(dst, src, va, vma);
Linus Torvalds6aab3412005-11-28 14:34:23 -08002070}
2071
Linus Torvalds1da177e2005-04-16 15:20:36 -07002072/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002073 * This routine handles present pages, when users try to write
2074 * to a shared page. It is done by copying the page to a new address
2075 * and decrementing the shared-page counter for the old page.
2076 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07002077 * Note that this routine assumes that the protection checks have been
2078 * done by the caller (the low-level page fault routine in most cases).
2079 * Thus we can safely just mark it writable once we've done any necessary
2080 * COW.
2081 *
2082 * We also mark the page dirty at this point even though the page will
2083 * change only once the write actually happens. This avoids a few races,
2084 * and potentially makes it more efficient.
2085 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002086 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2087 * but allow concurrent faults), with pte both mapped and locked.
2088 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002090static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2091 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002092 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002093{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00002094 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095 pte_t entry;
Nick Piggin83c54072007-07-19 01:47:05 -07002096 int reuse = 0, ret = 0;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002097 int page_mkwrite = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002098 struct page *dirty_page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002099
Linus Torvalds6aab3412005-11-28 14:34:23 -08002100 old_page = vm_normal_page(vma, address, orig_pte);
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002101 if (!old_page) {
2102 /*
2103 * VM_MIXEDMAP !pfn_valid() case
2104 *
2105 * We should not cow pages in a shared writeable mapping.
2106 * Just mark the pages writable as we can't do any dirty
2107 * accounting on raw pfn maps.
2108 */
2109 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2110 (VM_WRITE|VM_SHARED))
2111 goto reuse;
Linus Torvalds6aab3412005-11-28 14:34:23 -08002112 goto gotten;
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002113 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002114
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002115 /*
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002116 * Take out anonymous pages first, anonymous shared vmas are
2117 * not dirty accountable.
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002118 */
Hugh Dickins9a840892009-09-21 17:02:01 -07002119 if (PageAnon(old_page) && !PageKsm(old_page)) {
Hugh Dickinsab967d82009-01-06 14:39:33 -08002120 if (!trylock_page(old_page)) {
2121 page_cache_get(old_page);
2122 pte_unmap_unlock(page_table, ptl);
2123 lock_page(old_page);
2124 page_table = pte_offset_map_lock(mm, pmd, address,
2125 &ptl);
2126 if (!pte_same(*page_table, orig_pte)) {
2127 unlock_page(old_page);
2128 page_cache_release(old_page);
2129 goto unlock;
2130 }
2131 page_cache_release(old_page);
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002132 }
Hugh Dickins7b1fe592009-01-06 14:39:34 -08002133 reuse = reuse_swap_page(old_page);
Rik van Rielc44b6742010-03-05 13:42:09 -08002134 if (reuse)
2135 /*
2136 * The page is all ours. Move it to our anon_vma so
2137 * the rmap code will not search our parent or siblings.
2138 * Protected against the rmap code by the page lock.
2139 */
2140 page_move_anon_rmap(old_page, vma, address);
Hugh Dickinsab967d82009-01-06 14:39:33 -08002141 unlock_page(old_page);
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002142 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002143 (VM_WRITE|VM_SHARED))) {
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002144 /*
2145 * Only catch write-faults on shared writable pages,
2146 * read-only shared pages can get COWed by
2147 * get_user_pages(.write=1, .force=1).
2148 */
David Howells9637a5e2006-06-23 02:03:43 -07002149 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
Nick Pigginc2ec1752009-03-31 15:23:21 -07002150 struct vm_fault vmf;
2151 int tmp;
2152
2153 vmf.virtual_address = (void __user *)(address &
2154 PAGE_MASK);
2155 vmf.pgoff = old_page->index;
2156 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2157 vmf.page = old_page;
2158
David Howells9637a5e2006-06-23 02:03:43 -07002159 /*
2160 * Notify the address space that the page is about to
2161 * become writable so that it can prohibit this or wait
2162 * for the page to get into an appropriate state.
2163 *
2164 * We do this without the lock held, so that it can
2165 * sleep if it needs to.
2166 */
2167 page_cache_get(old_page);
2168 pte_unmap_unlock(page_table, ptl);
2169
Nick Pigginc2ec1752009-03-31 15:23:21 -07002170 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2171 if (unlikely(tmp &
2172 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2173 ret = tmp;
David Howells9637a5e2006-06-23 02:03:43 -07002174 goto unwritable_page;
Nick Pigginc2ec1752009-03-31 15:23:21 -07002175 }
Nick Pigginb827e492009-04-30 15:08:16 -07002176 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2177 lock_page(old_page);
2178 if (!old_page->mapping) {
2179 ret = 0; /* retry the fault */
2180 unlock_page(old_page);
2181 goto unwritable_page;
2182 }
2183 } else
2184 VM_BUG_ON(!PageLocked(old_page));
David Howells9637a5e2006-06-23 02:03:43 -07002185
David Howells9637a5e2006-06-23 02:03:43 -07002186 /*
2187 * Since we dropped the lock we need to revalidate
2188 * the PTE as someone else may have changed it. If
2189 * they did, we just return, as we can count on the
2190 * MMU to tell us if they didn't also make it writable.
2191 */
2192 page_table = pte_offset_map_lock(mm, pmd, address,
2193 &ptl);
Nick Pigginb827e492009-04-30 15:08:16 -07002194 if (!pte_same(*page_table, orig_pte)) {
2195 unlock_page(old_page);
2196 page_cache_release(old_page);
David Howells9637a5e2006-06-23 02:03:43 -07002197 goto unlock;
Nick Pigginb827e492009-04-30 15:08:16 -07002198 }
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002199
2200 page_mkwrite = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002201 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002202 dirty_page = old_page;
2203 get_page(dirty_page);
David Howells9637a5e2006-06-23 02:03:43 -07002204 reuse = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002205 }
2206
2207 if (reuse) {
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002208reuse:
David Howells9637a5e2006-06-23 02:03:43 -07002209 flush_cache_page(vma, address, pte_pfn(orig_pte));
2210 entry = pte_mkyoung(orig_pte);
2211 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
KAMEZAWA Hiroyuki954ffcb2007-10-16 01:25:44 -07002212 if (ptep_set_access_flags(vma, address, page_table, entry,1))
Russell King4b3073e2009-12-18 16:40:18 +00002213 update_mmu_cache(vma, address, page_table);
David Howells9637a5e2006-06-23 02:03:43 -07002214 ret |= VM_FAULT_WRITE;
2215 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002216 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002217
2218 /*
2219 * Ok, we need to copy. Oh, well..
2220 */
Nick Pigginb5810032005-10-29 18:16:12 -07002221 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08002222gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002223 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002224
2225 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07002226 goto oom;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002227
Hugh Dickins62eede62009-09-21 17:03:34 -07002228 if (is_zero_pfn(pte_pfn(orig_pte))) {
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002229 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2230 if (!new_page)
2231 goto oom;
2232 } else {
2233 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2234 if (!new_page)
2235 goto oom;
2236 cow_user_page(new_page, old_page, address, vma);
2237 }
2238 __SetPageUptodate(new_page);
2239
Nick Pigginb291f002008-10-18 20:26:44 -07002240 /*
2241 * Don't let another task, with possibly unlocked vma,
2242 * keep the mlocked page.
2243 */
Carsten Otteab926612009-02-04 15:12:16 -08002244 if ((vma->vm_flags & VM_LOCKED) && old_page) {
Nick Pigginb291f002008-10-18 20:26:44 -07002245 lock_page(old_page); /* for LRU manipulation */
2246 clear_page_mlock(old_page);
2247 unlock_page(old_page);
2248 }
Hugh Dickins65500d22005-10-29 18:15:59 -07002249
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002250 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002251 goto oom_free_new;
2252
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253 /*
2254 * Re-check the pte - we dropped the lock
2255 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002256 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07002257 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08002258 if (old_page) {
Hugh Dickins920fc352005-11-21 21:32:17 -08002259 if (!PageAnon(old_page)) {
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002260 dec_mm_counter_fast(mm, MM_FILEPAGES);
2261 inc_mm_counter_fast(mm, MM_ANONPAGES);
Hugh Dickins920fc352005-11-21 21:32:17 -08002262 }
2263 } else
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002264 inc_mm_counter_fast(mm, MM_ANONPAGES);
Ben Collinseca35132005-11-29 11:45:26 -08002265 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07002266 entry = mk_pte(new_page, vma->vm_page_prot);
2267 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Siddha, Suresh B4ce072f2006-09-29 01:58:42 -07002268 /*
2269 * Clear the pte entry and flush it first, before updating the
2270 * pte with the new entry. This will avoid a race condition
2271 * seen in the presence of one thread doing SMC and another
2272 * thread doing COW.
2273 */
Izik Eidus828502d2009-09-21 17:01:51 -07002274 ptep_clear_flush(vma, address, page_table);
Nick Piggin9617d952006-01-06 00:11:12 -08002275 page_add_new_anon_rmap(new_page, vma, address);
Izik Eidus828502d2009-09-21 17:01:51 -07002276 /*
2277 * We call the notify macro here because, when using secondary
2278 * mmu page tables (such as kvm shadow page tables), we want the
2279 * new page to be mapped directly into the secondary page table.
2280 */
2281 set_pte_at_notify(mm, address, page_table, entry);
Russell King4b3073e2009-12-18 16:40:18 +00002282 update_mmu_cache(vma, address, page_table);
Nick Piggin945754a2008-06-23 14:30:30 +02002283 if (old_page) {
2284 /*
2285 * Only after switching the pte to the new page may
2286 * we remove the mapcount here. Otherwise another
2287 * process may come and find the rmap count decremented
2288 * before the pte is switched to the new page, and
2289 * "reuse" the old page writing into it while our pte
2290 * here still points into it and can be read by other
2291 * threads.
2292 *
2293 * The critical issue is to order this
2294 * page_remove_rmap with the ptp_clear_flush above.
2295 * Those stores are ordered by (if nothing else,)
2296 * the barrier present in the atomic_add_negative
2297 * in page_remove_rmap.
2298 *
2299 * Then the TLB flush in ptep_clear_flush ensures that
2300 * no process can access the old page before the
2301 * decremented mapcount is visible. And the old page
2302 * cannot be reused until after the decremented
2303 * mapcount is visible. So transitively, TLBs to
2304 * old page will be flushed before it can be reused.
2305 */
Hugh Dickinsedc315f2009-01-06 14:40:11 -08002306 page_remove_rmap(old_page);
Nick Piggin945754a2008-06-23 14:30:30 +02002307 }
2308
Linus Torvalds1da177e2005-04-16 15:20:36 -07002309 /* Free the old page.. */
2310 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002311 ret |= VM_FAULT_WRITE;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002312 } else
2313 mem_cgroup_uncharge_page(new_page);
2314
Hugh Dickins920fc352005-11-21 21:32:17 -08002315 if (new_page)
2316 page_cache_release(new_page);
2317 if (old_page)
2318 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002319unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002320 pte_unmap_unlock(page_table, ptl);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002321 if (dirty_page) {
Nick Piggin79352892007-07-19 01:47:22 -07002322 /*
2323 * Yes, Virginia, this is actually required to prevent a race
2324 * with clear_page_dirty_for_io() from clearing the page dirty
2325 * bit after it clear all dirty ptes, but before a racing
2326 * do_wp_page installs a dirty pte.
2327 *
2328 * do_no_page is protected similarly.
2329 */
Nick Pigginb827e492009-04-30 15:08:16 -07002330 if (!page_mkwrite) {
2331 wait_on_page_locked(dirty_page);
2332 set_page_dirty_balance(dirty_page, page_mkwrite);
2333 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002334 put_page(dirty_page);
Nick Pigginb827e492009-04-30 15:08:16 -07002335 if (page_mkwrite) {
2336 struct address_space *mapping = dirty_page->mapping;
2337
2338 set_page_dirty(dirty_page);
2339 unlock_page(dirty_page);
2340 page_cache_release(dirty_page);
2341 if (mapping) {
2342 /*
2343 * Some device drivers do not set page.mapping
2344 * but still dirty their pages
2345 */
2346 balance_dirty_pages_ratelimited(mapping);
2347 }
2348 }
2349
2350 /* file_update_time outside page_lock */
2351 if (vma->vm_file)
2352 file_update_time(vma->vm_file);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002353 }
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002354 return ret;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002355oom_free_new:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002356 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002357oom:
Nick Pigginb827e492009-04-30 15:08:16 -07002358 if (old_page) {
2359 if (page_mkwrite) {
2360 unlock_page(old_page);
2361 page_cache_release(old_page);
2362 }
Hugh Dickins920fc352005-11-21 21:32:17 -08002363 page_cache_release(old_page);
Nick Pigginb827e492009-04-30 15:08:16 -07002364 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07002366
2367unwritable_page:
2368 page_cache_release(old_page);
Nick Pigginc2ec1752009-03-31 15:23:21 -07002369 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370}
2371
2372/*
2373 * Helper functions for unmap_mapping_range().
2374 *
2375 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2376 *
2377 * We have to restart searching the prio_tree whenever we drop the lock,
2378 * since the iterator is only valid while the lock is held, and anyway
2379 * a later vma might be split and reinserted earlier while lock dropped.
2380 *
2381 * The list of nonlinear vmas could be handled more efficiently, using
2382 * a placeholder, but handle it in the same way until a need is shown.
2383 * It is important to search the prio_tree before nonlinear list: a vma
2384 * may become nonlinear and be shifted from prio_tree to nonlinear list
2385 * while the lock is dropped; but never shifted from list to prio_tree.
2386 *
2387 * In order to make forward progress despite restarting the search,
2388 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2389 * quickly skip it next time around. Since the prio_tree search only
2390 * shows us those vmas affected by unmapping the range in question, we
2391 * can't efficiently keep all vmas in step with mapping->truncate_count:
2392 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2393 * mapping->truncate_count and vma->vm_truncate_count are protected by
2394 * i_mmap_lock.
2395 *
2396 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07002397 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002398 * and restart from that address when we reach that vma again. It might
2399 * have been split or merged, shrunk or extended, but never shifted: so
2400 * restart_addr remains valid so long as it remains in the vma's range.
2401 * unmap_mapping_range forces truncate_count to leap over page-aligned
2402 * values so we can save vma's restart_addr in its truncate_count field.
2403 */
2404#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2405
2406static void reset_vma_truncate_counts(struct address_space *mapping)
2407{
2408 struct vm_area_struct *vma;
2409 struct prio_tree_iter iter;
2410
2411 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2412 vma->vm_truncate_count = 0;
2413 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2414 vma->vm_truncate_count = 0;
2415}
2416
2417static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2418 unsigned long start_addr, unsigned long end_addr,
2419 struct zap_details *details)
2420{
2421 unsigned long restart_addr;
2422 int need_break;
2423
Nick Piggind00806b2007-07-19 01:46:57 -07002424 /*
2425 * files that support invalidating or truncating portions of the
Nick Piggind0217ac2007-07-19 01:47:03 -07002426 * file from under mmaped areas must have their ->fault function
Nick Piggin83c54072007-07-19 01:47:05 -07002427 * return a locked page (and set VM_FAULT_LOCKED in the return).
2428 * This provides synchronisation against concurrent unmapping here.
Nick Piggind00806b2007-07-19 01:46:57 -07002429 */
Nick Piggind00806b2007-07-19 01:46:57 -07002430
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431again:
2432 restart_addr = vma->vm_truncate_count;
2433 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2434 start_addr = restart_addr;
2435 if (start_addr >= end_addr) {
2436 /* Top of vma has been split off since last time */
2437 vma->vm_truncate_count = details->truncate_count;
2438 return 0;
2439 }
2440 }
2441
Hugh Dickinsee39b372005-04-19 13:29:15 -07002442 restart_addr = zap_page_range(vma, start_addr,
2443 end_addr - start_addr, details);
Nick Piggin95c354f2008-01-30 13:31:20 +01002444 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002445
Hugh Dickinsee39b372005-04-19 13:29:15 -07002446 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002447 /* We have now completed this vma: mark it so */
2448 vma->vm_truncate_count = details->truncate_count;
2449 if (!need_break)
2450 return 0;
2451 } else {
2452 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07002453 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002454 if (!need_break)
2455 goto again;
2456 }
2457
2458 spin_unlock(details->i_mmap_lock);
2459 cond_resched();
2460 spin_lock(details->i_mmap_lock);
2461 return -EINTR;
2462}
2463
2464static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2465 struct zap_details *details)
2466{
2467 struct vm_area_struct *vma;
2468 struct prio_tree_iter iter;
2469 pgoff_t vba, vea, zba, zea;
2470
2471restart:
2472 vma_prio_tree_foreach(vma, &iter, root,
2473 details->first_index, details->last_index) {
2474 /* Skip quickly over those we have already dealt with */
2475 if (vma->vm_truncate_count == details->truncate_count)
2476 continue;
2477
2478 vba = vma->vm_pgoff;
2479 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2480 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2481 zba = details->first_index;
2482 if (zba < vba)
2483 zba = vba;
2484 zea = details->last_index;
2485 if (zea > vea)
2486 zea = vea;
2487
2488 if (unmap_mapping_range_vma(vma,
2489 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2490 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2491 details) < 0)
2492 goto restart;
2493 }
2494}
2495
2496static inline void unmap_mapping_range_list(struct list_head *head,
2497 struct zap_details *details)
2498{
2499 struct vm_area_struct *vma;
2500
2501 /*
2502 * In nonlinear VMAs there is no correspondence between virtual address
2503 * offset and file offset. So we must perform an exhaustive search
2504 * across *all* the pages in each nonlinear VMA, not just the pages
2505 * whose virtual address lies outside the file truncation point.
2506 */
2507restart:
2508 list_for_each_entry(vma, head, shared.vm_set.list) {
2509 /* Skip quickly over those we have already dealt with */
2510 if (vma->vm_truncate_count == details->truncate_count)
2511 continue;
2512 details->nonlinear_vma = vma;
2513 if (unmap_mapping_range_vma(vma, vma->vm_start,
2514 vma->vm_end, details) < 0)
2515 goto restart;
2516 }
2517}
2518
2519/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08002520 * 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 -07002521 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002522 * @holebegin: byte in first page to unmap, relative to the start of
2523 * the underlying file. This will be rounded down to a PAGE_SIZE
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +10002524 * boundary. Note that this is different from truncate_pagecache(), which
Linus Torvalds1da177e2005-04-16 15:20:36 -07002525 * must keep the partial page. In contrast, we must get rid of
2526 * partial pages.
2527 * @holelen: size of prospective hole in bytes. This will be rounded
2528 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2529 * end of the file.
2530 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2531 * but 0 when invalidating pagecache, don't throw away private data.
2532 */
2533void unmap_mapping_range(struct address_space *mapping,
2534 loff_t const holebegin, loff_t const holelen, int even_cows)
2535{
2536 struct zap_details details;
2537 pgoff_t hba = holebegin >> PAGE_SHIFT;
2538 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2539
2540 /* Check for overflow. */
2541 if (sizeof(holelen) > sizeof(hlen)) {
2542 long long holeend =
2543 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2544 if (holeend & ~(long long)ULONG_MAX)
2545 hlen = ULONG_MAX - hba + 1;
2546 }
2547
2548 details.check_mapping = even_cows? NULL: mapping;
2549 details.nonlinear_vma = NULL;
2550 details.first_index = hba;
2551 details.last_index = hba + hlen - 1;
2552 if (details.last_index < details.first_index)
2553 details.last_index = ULONG_MAX;
2554 details.i_mmap_lock = &mapping->i_mmap_lock;
2555
2556 spin_lock(&mapping->i_mmap_lock);
2557
Nick Piggind00806b2007-07-19 01:46:57 -07002558 /* Protect against endless unmapping loops */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002559 mapping->truncate_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002560 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2561 if (mapping->truncate_count == 0)
2562 reset_vma_truncate_counts(mapping);
2563 mapping->truncate_count++;
2564 }
2565 details.truncate_count = mapping->truncate_count;
2566
2567 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2568 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2569 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2570 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2571 spin_unlock(&mapping->i_mmap_lock);
2572}
2573EXPORT_SYMBOL(unmap_mapping_range);
2574
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002575int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2576{
2577 struct address_space *mapping = inode->i_mapping;
2578
2579 /*
2580 * If the underlying filesystem is not going to provide
2581 * a way to truncate a range of blocks (punch a hole) -
2582 * we should return failure right now.
2583 */
Al Viroacfa4382008-12-04 10:06:33 -05002584 if (!inode->i_op->truncate_range)
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002585 return -ENOSYS;
2586
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002587 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002588 down_write(&inode->i_alloc_sem);
2589 unmap_mapping_range(mapping, offset, (end - offset), 1);
2590 truncate_inode_pages_range(mapping, offset, end);
Nick Piggind00806b2007-07-19 01:46:57 -07002591 unmap_mapping_range(mapping, offset, (end - offset), 1);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002592 inode->i_op->truncate_range(inode, offset, end);
2593 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002594 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002595
2596 return 0;
2597}
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002598
Linus Torvalds1da177e2005-04-16 15:20:36 -07002599/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002600 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2601 * but allow concurrent faults), and pte mapped but not yet locked.
2602 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002603 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002604static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2605 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002606 unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002607{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002608 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002609 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07002610 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002611 pte_t pte;
KAMEZAWA Hiroyuki7a81b882009-01-07 18:07:48 -08002612 struct mem_cgroup *ptr = NULL;
Nick Piggin83c54072007-07-19 01:47:05 -07002613 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002614
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002615 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002616 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07002617
2618 entry = pte_to_swp_entry(orig_pte);
Andi Kleend1737fd2009-09-16 11:50:06 +02002619 if (unlikely(non_swap_entry(entry))) {
2620 if (is_migration_entry(entry)) {
2621 migration_entry_wait(mm, pmd, address);
2622 } else if (is_hwpoison_entry(entry)) {
2623 ret = VM_FAULT_HWPOISON;
2624 } else {
2625 print_bad_pte(vma, address, orig_pte, NULL);
Hugh Dickinsd99be1a2009-12-14 17:59:04 -08002626 ret = VM_FAULT_SIGBUS;
Andi Kleend1737fd2009-09-16 11:50:06 +02002627 }
Christoph Lameter06972122006-06-23 02:03:35 -07002628 goto out;
2629 }
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002630 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631 page = lookup_swap_cache(entry);
2632 if (!page) {
Hugh Dickinsa5c9b692009-06-23 12:36:58 -07002633 grab_swap_token(mm); /* Contend for token _before_ read-in */
Hugh Dickins02098fe2008-02-04 22:28:42 -08002634 page = swapin_readahead(entry,
2635 GFP_HIGHUSER_MOVABLE, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002636 if (!page) {
2637 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002638 * Back out if somebody else faulted in this pte
2639 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002640 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002641 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002642 if (likely(pte_same(*page_table, orig_pte)))
2643 ret = VM_FAULT_OOM;
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002644 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Hugh Dickins65500d22005-10-29 18:15:59 -07002645 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646 }
2647
2648 /* Had to read the page from swap area: Major fault */
2649 ret = VM_FAULT_MAJOR;
Christoph Lameterf8891e52006-06-30 01:55:45 -07002650 count_vm_event(PGMAJFAULT);
Andi Kleend1737fd2009-09-16 11:50:06 +02002651 } else if (PageHWPoison(page)) {
Wu Fengguang71f72522009-12-16 12:19:58 +01002652 /*
2653 * hwpoisoned dirty swapcache pages are kept for killing
2654 * owner processes (which may be unknown at hwpoison time)
2655 */
Andi Kleend1737fd2009-09-16 11:50:06 +02002656 ret = VM_FAULT_HWPOISON;
2657 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Andi Kleen4779cb32009-10-14 01:51:41 +02002658 goto out_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002659 }
2660
Linus Torvalds1da177e2005-04-16 15:20:36 -07002661 lock_page(page);
Balbir Singh20a10222007-11-14 17:00:33 -08002662 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002663
Hugh Dickins5ad64682009-12-14 17:59:24 -08002664 page = ksm_might_need_to_copy(page, vma, address);
2665 if (!page) {
2666 ret = VM_FAULT_OOM;
2667 goto out;
2668 }
2669
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002670 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
KAMEZAWA Hiroyuki073e5872008-10-18 20:28:08 -07002671 ret = VM_FAULT_OOM;
Johannes Weinerbc43f752009-04-30 15:08:08 -07002672 goto out_page;
KAMEZAWA Hiroyuki073e5872008-10-18 20:28:08 -07002673 }
2674
Linus Torvalds1da177e2005-04-16 15:20:36 -07002675 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002676 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002677 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002678 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07002679 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07002680 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002681
2682 if (unlikely(!PageUptodate(page))) {
2683 ret = VM_FAULT_SIGBUS;
2684 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002685 }
2686
KAMEZAWA Hiroyuki8c7c6e32009-01-07 18:08:00 -08002687 /*
2688 * The page isn't present yet, go ahead with the fault.
2689 *
2690 * Be careful about the sequence of operations here.
2691 * To get its accounting right, reuse_swap_page() must be called
2692 * while the page is counted on swap but not yet in mapcount i.e.
2693 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2694 * must be called after the swap_free(), or it will never succeed.
KAMEZAWA Hiroyuki03f3c432009-01-07 18:08:31 -08002695 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2696 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2697 * in page->private. In this case, a record in swap_cgroup is silently
2698 * discarded at swap_free().
KAMEZAWA Hiroyuki8c7c6e32009-01-07 18:08:00 -08002699 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002700
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002701 inc_mm_counter_fast(mm, MM_ANONPAGES);
KAMEZAWA Hiroyukib084d432010-03-05 13:41:42 -08002702 dec_mm_counter_fast(mm, MM_SWAPENTS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002703 pte = mk_pte(page, vma->vm_page_prot);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002704 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002705 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002706 flags &= ~FAULT_FLAG_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002707 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002708 flush_icache_page(vma, page);
2709 set_pte_at(mm, address, page_table, pte);
2710 page_add_anon_rmap(page, vma, address);
KAMEZAWA Hiroyuki03f3c432009-01-07 18:08:31 -08002711 /* It's better to call commit-charge after rmap is established */
2712 mem_cgroup_commit_charge_swapin(page, ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002713
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002714 swap_free(entry);
Nick Pigginb291f002008-10-18 20:26:44 -07002715 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -08002716 try_to_free_swap(page);
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002717 unlock_page(page);
2718
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002719 if (flags & FAULT_FLAG_WRITE) {
Hugh Dickins61469f12008-03-04 14:29:04 -08002720 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2721 if (ret & VM_FAULT_ERROR)
2722 ret &= VM_FAULT_ERROR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002723 goto out;
2724 }
2725
2726 /* No need to invalidate - it was non-present before */
Russell King4b3073e2009-12-18 16:40:18 +00002727 update_mmu_cache(vma, address, page_table);
Hugh Dickins65500d22005-10-29 18:15:59 -07002728unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002729 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002730out:
2731 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002732out_nomap:
KAMEZAWA Hiroyuki7a81b882009-01-07 18:07:48 -08002733 mem_cgroup_cancel_charge_swapin(ptr);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002734 pte_unmap_unlock(page_table, ptl);
Johannes Weinerbc43f752009-04-30 15:08:08 -07002735out_page:
Kirill Korotaevb8107482005-05-16 21:53:50 -07002736 unlock_page(page);
Andi Kleen4779cb32009-10-14 01:51:41 +02002737out_release:
Kirill Korotaevb8107482005-05-16 21:53:50 -07002738 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002739 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002740}
2741
2742/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002743 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2744 * but allow concurrent faults), and pte mapped but not yet locked.
2745 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002746 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002747static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2748 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002749 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002750{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002751 struct page *page;
2752 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002753 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002754
Hugh Dickins62eede62009-09-21 17:03:34 -07002755 if (!(flags & FAULT_FLAG_WRITE)) {
2756 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2757 vma->vm_page_prot));
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002758 ptl = pte_lockptr(mm, pmd);
2759 spin_lock(ptl);
2760 if (!pte_none(*page_table))
2761 goto unlock;
2762 goto setpte;
2763 }
2764
Nick Piggin557ed1f2007-10-16 01:24:40 -07002765 /* Allocate our own private page. */
2766 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002767
Nick Piggin557ed1f2007-10-16 01:24:40 -07002768 if (unlikely(anon_vma_prepare(vma)))
2769 goto oom;
2770 page = alloc_zeroed_user_highpage_movable(vma, address);
2771 if (!page)
2772 goto oom;
Nick Piggin0ed361d2008-02-04 22:29:34 -08002773 __SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002774
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002775 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002776 goto oom_free_page;
2777
Nick Piggin557ed1f2007-10-16 01:24:40 -07002778 entry = mk_pte(page, vma->vm_page_prot);
Hugh Dickins1ac0cb52009-09-21 17:03:29 -07002779 if (vma->vm_flags & VM_WRITE)
2780 entry = pte_mkwrite(pte_mkdirty(entry));
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002781
Nick Piggin557ed1f2007-10-16 01:24:40 -07002782 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Andrea Arcangeli1c2fb7a2009-09-21 17:02:22 -07002783 if (!pte_none(*page_table))
Nick Piggin557ed1f2007-10-16 01:24:40 -07002784 goto release;
Hugh Dickins9ba69292009-09-21 17:02:20 -07002785
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002786 inc_mm_counter_fast(mm, MM_ANONPAGES);
Nick Piggin557ed1f2007-10-16 01:24:40 -07002787 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002788setpte:
Hugh Dickins65500d22005-10-29 18:15:59 -07002789 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002790
2791 /* No need to invalidate - it was non-present before */
Russell King4b3073e2009-12-18 16:40:18 +00002792 update_mmu_cache(vma, address, page_table);
Hugh Dickins65500d22005-10-29 18:15:59 -07002793unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002794 pte_unmap_unlock(page_table, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002795 return 0;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002796release:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002797 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002798 page_cache_release(page);
2799 goto unlock;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002800oom_free_page:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002801 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002802oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002803 return VM_FAULT_OOM;
2804}
2805
2806/*
Nick Piggin54cb8822007-07-19 01:46:59 -07002807 * __do_fault() tries to create a new page mapping. It aggressively
Linus Torvalds1da177e2005-04-16 15:20:36 -07002808 * tries to share with existing pages, but makes a separate copy if
Nick Piggin54cb8822007-07-19 01:46:59 -07002809 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2810 * the next page fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002811 *
2812 * As this is called only for pages that do not currently exist, we
2813 * do not need to flush old virtual caches or the TLB.
2814 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002815 * We enter with non-exclusive mmap_sem (to exclude vma changes,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002816 * but allow concurrent faults), and pte neither mapped nor locked.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002817 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002818 */
Nick Piggin54cb8822007-07-19 01:46:59 -07002819static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002820 unsigned long address, pmd_t *pmd,
Nick Piggin54cb8822007-07-19 01:46:59 -07002821 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002822{
Hugh Dickins16abfa02007-10-04 16:56:06 +01002823 pte_t *page_table;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002824 spinlock_t *ptl;
Nick Piggind0217ac2007-07-19 01:47:03 -07002825 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002826 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002827 int anon = 0;
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002828 int charged = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002829 struct page *dirty_page = NULL;
Nick Piggind0217ac2007-07-19 01:47:03 -07002830 struct vm_fault vmf;
2831 int ret;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002832 int page_mkwrite = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07002833
Nick Piggind0217ac2007-07-19 01:47:03 -07002834 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2835 vmf.pgoff = pgoff;
2836 vmf.flags = flags;
2837 vmf.page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002838
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002839 ret = vma->vm_ops->fault(vma, &vmf);
2840 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2841 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002842
Andi Kleena3b947e2009-09-16 11:50:08 +02002843 if (unlikely(PageHWPoison(vmf.page))) {
2844 if (ret & VM_FAULT_LOCKED)
2845 unlock_page(vmf.page);
2846 return VM_FAULT_HWPOISON;
2847 }
2848
Nick Piggind00806b2007-07-19 01:46:57 -07002849 /*
Nick Piggind0217ac2007-07-19 01:47:03 -07002850 * For consistency in subsequent calls, make the faulted page always
Nick Piggind00806b2007-07-19 01:46:57 -07002851 * locked.
2852 */
Nick Piggin83c54072007-07-19 01:47:05 -07002853 if (unlikely(!(ret & VM_FAULT_LOCKED)))
Nick Piggind0217ac2007-07-19 01:47:03 -07002854 lock_page(vmf.page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002855 else
Nick Piggind0217ac2007-07-19 01:47:03 -07002856 VM_BUG_ON(!PageLocked(vmf.page));
Nick Piggind00806b2007-07-19 01:46:57 -07002857
Linus Torvalds1da177e2005-04-16 15:20:36 -07002858 /*
2859 * Should we do an early C-O-W break?
2860 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002861 page = vmf.page;
Nick Piggin54cb8822007-07-19 01:46:59 -07002862 if (flags & FAULT_FLAG_WRITE) {
David Howells9637a5e2006-06-23 02:03:43 -07002863 if (!(vma->vm_flags & VM_SHARED)) {
Nick Piggin54cb8822007-07-19 01:46:59 -07002864 anon = 1;
Nick Piggind00806b2007-07-19 01:46:57 -07002865 if (unlikely(anon_vma_prepare(vma))) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002866 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002867 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002868 }
Nick Piggin83c54072007-07-19 01:47:05 -07002869 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2870 vma, address);
Nick Piggind00806b2007-07-19 01:46:57 -07002871 if (!page) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002872 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002873 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002874 }
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002875 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002876 ret = VM_FAULT_OOM;
2877 page_cache_release(page);
2878 goto out;
2879 }
2880 charged = 1;
Nick Pigginb291f002008-10-18 20:26:44 -07002881 /*
2882 * Don't let another task, with possibly unlocked vma,
2883 * keep the mlocked page.
2884 */
2885 if (vma->vm_flags & VM_LOCKED)
2886 clear_page_mlock(vmf.page);
Nick Piggind0217ac2007-07-19 01:47:03 -07002887 copy_user_highpage(page, vmf.page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002888 __SetPageUptodate(page);
David Howells9637a5e2006-06-23 02:03:43 -07002889 } else {
Nick Piggin54cb8822007-07-19 01:46:59 -07002890 /*
2891 * If the page will be shareable, see if the backing
David Howells9637a5e2006-06-23 02:03:43 -07002892 * address space wants to know that the page is about
Nick Piggin54cb8822007-07-19 01:46:59 -07002893 * to become writable
2894 */
Mark Fasheh69676142007-07-19 01:47:00 -07002895 if (vma->vm_ops->page_mkwrite) {
Nick Pigginc2ec1752009-03-31 15:23:21 -07002896 int tmp;
2897
Mark Fasheh69676142007-07-19 01:47:00 -07002898 unlock_page(page);
Nick Pigginb827e492009-04-30 15:08:16 -07002899 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
Nick Pigginc2ec1752009-03-31 15:23:21 -07002900 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2901 if (unlikely(tmp &
2902 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2903 ret = tmp;
Nick Pigginb827e492009-04-30 15:08:16 -07002904 goto unwritable_page;
Mark Fasheh69676142007-07-19 01:47:00 -07002905 }
Nick Pigginb827e492009-04-30 15:08:16 -07002906 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2907 lock_page(page);
2908 if (!page->mapping) {
2909 ret = 0; /* retry the fault */
2910 unlock_page(page);
2911 goto unwritable_page;
2912 }
2913 } else
2914 VM_BUG_ON(!PageLocked(page));
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002915 page_mkwrite = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002916 }
2917 }
Nick Piggin54cb8822007-07-19 01:46:59 -07002918
Linus Torvalds1da177e2005-04-16 15:20:36 -07002919 }
2920
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002921 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002922
2923 /*
2924 * This silly early PAGE_DIRTY setting removes a race
2925 * due to the bad i386 page protection. But it's valid
2926 * for other architectures too.
2927 *
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002928 * Note that if FAULT_FLAG_WRITE is set, we either now have
Linus Torvalds1da177e2005-04-16 15:20:36 -07002929 * an exclusive copy of the page, or this is a shared mapping,
2930 * so we can make it writable and dirty to avoid having to
2931 * handle that later.
2932 */
2933 /* Only go through if we didn't race with anybody else... */
Andrea Arcangeli1c2fb7a2009-09-21 17:02:22 -07002934 if (likely(pte_same(*page_table, orig_pte))) {
Nick Piggind00806b2007-07-19 01:46:57 -07002935 flush_icache_page(vma, page);
2936 entry = mk_pte(page, vma->vm_page_prot);
Nick Piggin54cb8822007-07-19 01:46:59 -07002937 if (flags & FAULT_FLAG_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002938 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002939 if (anon) {
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002940 inc_mm_counter_fast(mm, MM_ANONPAGES);
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002941 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002942 } else {
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002943 inc_mm_counter_fast(mm, MM_FILEPAGES);
Nick Piggind00806b2007-07-19 01:46:57 -07002944 page_add_file_rmap(page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002945 if (flags & FAULT_FLAG_WRITE) {
Nick Piggind00806b2007-07-19 01:46:57 -07002946 dirty_page = page;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002947 get_page(dirty_page);
2948 }
Hugh Dickins42946212005-10-29 18:16:05 -07002949 }
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002950 set_pte_at(mm, address, page_table, entry);
Nick Piggind00806b2007-07-19 01:46:57 -07002951
2952 /* no need to invalidate: a not-present page won't be cached */
Russell King4b3073e2009-12-18 16:40:18 +00002953 update_mmu_cache(vma, address, page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002954 } else {
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002955 if (charged)
2956 mem_cgroup_uncharge_page(page);
Nick Piggind00806b2007-07-19 01:46:57 -07002957 if (anon)
2958 page_cache_release(page);
2959 else
Nick Piggin54cb8822007-07-19 01:46:59 -07002960 anon = 1; /* no anon but release faulted_page */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002961 }
2962
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002963 pte_unmap_unlock(page_table, ptl);
Nick Piggind00806b2007-07-19 01:46:57 -07002964
2965out:
Nick Pigginb827e492009-04-30 15:08:16 -07002966 if (dirty_page) {
2967 struct address_space *mapping = page->mapping;
2968
2969 if (set_page_dirty(dirty_page))
2970 page_mkwrite = 1;
2971 unlock_page(dirty_page);
2972 put_page(dirty_page);
2973 if (page_mkwrite && mapping) {
2974 /*
2975 * Some device drivers do not set page.mapping but still
2976 * dirty their pages
2977 */
2978 balance_dirty_pages_ratelimited(mapping);
2979 }
2980
2981 /* file_update_time outside page_lock */
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03002982 if (vma->vm_file)
2983 file_update_time(vma->vm_file);
Nick Pigginb827e492009-04-30 15:08:16 -07002984 } else {
2985 unlock_page(vmf.page);
2986 if (anon)
2987 page_cache_release(vmf.page);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002988 }
Nick Piggind00806b2007-07-19 01:46:57 -07002989
Nick Piggin83c54072007-07-19 01:47:05 -07002990 return ret;
Nick Pigginb827e492009-04-30 15:08:16 -07002991
2992unwritable_page:
2993 page_cache_release(page);
2994 return ret;
Nick Piggin54cb8822007-07-19 01:46:59 -07002995}
Nick Piggind00806b2007-07-19 01:46:57 -07002996
Nick Piggin54cb8822007-07-19 01:46:59 -07002997static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2998 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002999 unsigned int flags, pte_t orig_pte)
Nick Piggin54cb8822007-07-19 01:46:59 -07003000{
3001 pgoff_t pgoff = (((address & PAGE_MASK)
Dean Nelson0da7e012007-10-16 01:24:45 -07003002 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
Nick Piggin54cb8822007-07-19 01:46:59 -07003003
Hugh Dickins16abfa02007-10-04 16:56:06 +01003004 pte_unmap(page_table);
3005 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Nick Piggin54cb8822007-07-19 01:46:59 -07003006}
3007
Jes Sorensenf4b81802006-09-27 01:50:10 -07003008/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003009 * Fault of a previously existing named mapping. Repopulate the pte
3010 * from the encoded file_pte if possible. This enables swappable
3011 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003012 *
3013 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3014 * but allow concurrent faults), and pte mapped but not yet locked.
3015 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003016 */
Nick Piggind0217ac2007-07-19 01:47:03 -07003017static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins65500d22005-10-29 18:15:59 -07003018 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003019 unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003020{
Hugh Dickins65500d22005-10-29 18:15:59 -07003021 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003022
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003023 flags |= FAULT_FLAG_NONLINEAR;
3024
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07003025 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Nick Piggin83c54072007-07-19 01:47:05 -07003026 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003027
Hugh Dickins2509ef22009-01-06 14:40:10 -08003028 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
Hugh Dickins65500d22005-10-29 18:15:59 -07003029 /*
3030 * Page table corrupted: show pte and kill process.
3031 */
Hugh Dickins3dc14742009-01-06 14:40:08 -08003032 print_bad_pte(vma, address, orig_pte, NULL);
Hugh Dickinsd99be1a2009-12-14 17:59:04 -08003033 return VM_FAULT_SIGBUS;
Hugh Dickins65500d22005-10-29 18:15:59 -07003034 }
Hugh Dickins65500d22005-10-29 18:15:59 -07003035
3036 pgoff = pte_to_pgoff(orig_pte);
Hugh Dickins16abfa02007-10-04 16:56:06 +01003037 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003038}
3039
3040/*
3041 * These routines also need to handle stuff like marking pages dirty
3042 * and/or accessed for architectures that don't do it in hardware (most
3043 * RISC architectures). The early dirtying is also good on the i386.
3044 *
3045 * There is also a hook called "update_mmu_cache()" that architectures
3046 * with external mmu caches can use to update those (ie the Sparc or
3047 * PowerPC hashed page tables that act as extended TLBs).
3048 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07003049 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3050 * but allow concurrent faults), and pte mapped but not yet locked.
3051 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003052 */
3053static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07003054 struct vm_area_struct *vma, unsigned long address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003055 pte_t *pte, pmd_t *pmd, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003056{
3057 pte_t entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003058 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003059
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07003060 entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003061 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07003062 if (pte_none(entry)) {
Jes Sorensenf4b81802006-09-27 01:50:10 -07003063 if (vma->vm_ops) {
Nick Piggin3c18ddd2008-04-28 02:12:10 -07003064 if (likely(vma->vm_ops->fault))
Nick Piggin54cb8822007-07-19 01:46:59 -07003065 return do_linear_fault(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003066 pte, pmd, flags, entry);
Jes Sorensenf4b81802006-09-27 01:50:10 -07003067 }
3068 return do_anonymous_page(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003069 pte, pmd, flags);
Hugh Dickins65500d22005-10-29 18:15:59 -07003070 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003071 if (pte_file(entry))
Nick Piggind0217ac2007-07-19 01:47:03 -07003072 return do_nonlinear_fault(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003073 pte, pmd, flags, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07003074 return do_swap_page(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003075 pte, pmd, flags, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003076 }
3077
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07003078 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003079 spin_lock(ptl);
3080 if (unlikely(!pte_same(*pte, entry)))
3081 goto unlock;
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003082 if (flags & FAULT_FLAG_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003083 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003084 return do_wp_page(mm, vma, address,
3085 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003086 entry = pte_mkdirty(entry);
3087 }
3088 entry = pte_mkyoung(entry);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003089 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
Russell King4b3073e2009-12-18 16:40:18 +00003090 update_mmu_cache(vma, address, pte);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07003091 } else {
3092 /*
3093 * This is needed only for protection faults but the arch code
3094 * is not yet telling us if this is a protection fault or not.
3095 * This still avoids useless tlb flushes for .text page faults
3096 * with threads.
3097 */
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003098 if (flags & FAULT_FLAG_WRITE)
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07003099 flush_tlb_page(vma, address);
3100 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003101unlock:
3102 pte_unmap_unlock(pte, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07003103 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003104}
3105
3106/*
3107 * By the time we get here, we already hold the mm semaphore
3108 */
Nick Piggin83c54072007-07-19 01:47:05 -07003109int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvaldsd06063c2009-04-10 09:01:23 -07003110 unsigned long address, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003111{
3112 pgd_t *pgd;
3113 pud_t *pud;
3114 pmd_t *pmd;
3115 pte_t *pte;
3116
3117 __set_current_state(TASK_RUNNING);
3118
Christoph Lameterf8891e52006-06-30 01:55:45 -07003119 count_vm_event(PGFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003120
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08003121 /* do counter updates before entering really critical section. */
3122 check_sync_rss_stat(current);
3123
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01003124 if (unlikely(is_vm_hugetlb_page(vma)))
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003125 return hugetlb_fault(mm, vma, address, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003126
Linus Torvalds1da177e2005-04-16 15:20:36 -07003127 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003128 pud = pud_alloc(mm, pgd, address);
3129 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003130 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003131 pmd = pmd_alloc(mm, pud, address);
3132 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003133 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003134 pte = pte_alloc_map(mm, pmd, address);
3135 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003136 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003137
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003138 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003139}
3140
3141#ifndef __PAGETABLE_PUD_FOLDED
3142/*
3143 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07003144 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003145 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07003146int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003147{
Hugh Dickinsc74df322005-10-29 18:16:23 -07003148 pud_t *new = pud_alloc_one(mm, address);
3149 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07003150 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003151
Nick Piggin362a61a2008-05-14 06:37:36 +02003152 smp_wmb(); /* See comment in __pte_alloc */
3153
Hugh Dickins872fec12005-10-29 18:16:21 -07003154 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003155 if (pgd_present(*pgd)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003156 pud_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003157 else
3158 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07003159 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003160 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003161}
3162#endif /* __PAGETABLE_PUD_FOLDED */
3163
3164#ifndef __PAGETABLE_PMD_FOLDED
3165/*
3166 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07003167 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003168 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07003169int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003170{
Hugh Dickinsc74df322005-10-29 18:16:23 -07003171 pmd_t *new = pmd_alloc_one(mm, address);
3172 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07003173 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003174
Nick Piggin362a61a2008-05-14 06:37:36 +02003175 smp_wmb(); /* See comment in __pte_alloc */
3176
Hugh Dickins872fec12005-10-29 18:16:21 -07003177 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003178#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07003179 if (pud_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003180 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003181 else
3182 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003183#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07003184 if (pgd_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003185 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003186 else
3187 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003188#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07003189 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003190 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003191}
3192#endif /* __PAGETABLE_PMD_FOLDED */
3193
3194int make_pages_present(unsigned long addr, unsigned long end)
3195{
3196 int ret, len, write;
3197 struct vm_area_struct * vma;
3198
3199 vma = find_vma(current->mm, addr);
3200 if (!vma)
KOSAKI Motohiroa4770972008-08-04 13:41:14 -07003201 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003202 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02003203 BUG_ON(addr >= end);
3204 BUG_ON(end > vma->vm_end);
Rolf Eike Beer68e116a2007-07-15 23:38:03 -07003205 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003206 ret = get_user_pages(current, current->mm, addr,
3207 len, write, 0, NULL, NULL);
Lee Schermerhornc11d69d2008-10-18 20:26:56 -07003208 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003209 return ret;
Lee Schermerhorn9978ad52008-10-18 20:26:56 -07003210 return ret == len ? 0 : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003211}
3212
Linus Torvalds1da177e2005-04-16 15:20:36 -07003213#if !defined(__HAVE_ARCH_GATE_AREA)
3214
3215#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07003216static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003217
3218static int __init gate_vma_init(void)
3219{
3220 gate_vma.vm_mm = NULL;
3221 gate_vma.vm_start = FIXADDR_USER_START;
3222 gate_vma.vm_end = FIXADDR_USER_END;
Roland McGrathb6558c42007-01-26 00:56:47 -08003223 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3224 gate_vma.vm_page_prot = __P101;
Roland McGrathf47aef52007-01-26 00:56:49 -08003225 /*
3226 * Make sure the vDSO gets into every core dump.
3227 * Dumping its contents makes post-mortem fully interpretable later
3228 * without matching up the same kernel and hardware config to see
3229 * what PC values meant.
3230 */
3231 gate_vma.vm_flags |= VM_ALWAYSDUMP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003232 return 0;
3233}
3234__initcall(gate_vma_init);
3235#endif
3236
3237struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
3238{
3239#ifdef AT_SYSINFO_EHDR
3240 return &gate_vma;
3241#else
3242 return NULL;
3243#endif
3244}
3245
3246int in_gate_area_no_task(unsigned long addr)
3247{
3248#ifdef AT_SYSINFO_EHDR
3249 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3250 return 1;
3251#endif
3252 return 0;
3253}
3254
3255#endif /* __HAVE_ARCH_GATE_AREA */
David Howells0ec76a12006-09-27 01:50:15 -07003256
Johannes Weinerf8ad0f492009-06-16 15:32:33 -07003257static int follow_pte(struct mm_struct *mm, unsigned long address,
3258 pte_t **ptepp, spinlock_t **ptlp)
3259{
3260 pgd_t *pgd;
3261 pud_t *pud;
3262 pmd_t *pmd;
3263 pte_t *ptep;
3264
3265 pgd = pgd_offset(mm, address);
3266 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3267 goto out;
3268
3269 pud = pud_offset(pgd, address);
3270 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3271 goto out;
3272
3273 pmd = pmd_offset(pud, address);
3274 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3275 goto out;
3276
3277 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3278 if (pmd_huge(*pmd))
3279 goto out;
3280
3281 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3282 if (!ptep)
3283 goto out;
3284 if (!pte_present(*ptep))
3285 goto unlock;
3286 *ptepp = ptep;
3287 return 0;
3288unlock:
3289 pte_unmap_unlock(ptep, *ptlp);
3290out:
3291 return -EINVAL;
3292}
3293
Johannes Weiner3b6748e2009-06-16 15:32:35 -07003294/**
3295 * follow_pfn - look up PFN at a user virtual address
3296 * @vma: memory mapping
3297 * @address: user virtual address
3298 * @pfn: location to store found PFN
3299 *
3300 * Only IO mappings and raw PFN mappings are allowed.
3301 *
3302 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3303 */
3304int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3305 unsigned long *pfn)
3306{
3307 int ret = -EINVAL;
3308 spinlock_t *ptl;
3309 pte_t *ptep;
3310
3311 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3312 return ret;
3313
3314 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3315 if (ret)
3316 return ret;
3317 *pfn = pte_pfn(*ptep);
3318 pte_unmap_unlock(ptep, ptl);
3319 return 0;
3320}
3321EXPORT_SYMBOL(follow_pfn);
3322
Rik van Riel28b2ee22008-07-23 21:27:05 -07003323#ifdef CONFIG_HAVE_IOREMAP_PROT
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003324int follow_phys(struct vm_area_struct *vma,
3325 unsigned long address, unsigned int flags,
3326 unsigned long *prot, resource_size_t *phys)
Rik van Riel28b2ee22008-07-23 21:27:05 -07003327{
Johannes Weiner03668a42009-06-16 15:32:34 -07003328 int ret = -EINVAL;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003329 pte_t *ptep, pte;
3330 spinlock_t *ptl;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003331
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003332 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3333 goto out;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003334
Johannes Weiner03668a42009-06-16 15:32:34 -07003335 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003336 goto out;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003337 pte = *ptep;
Johannes Weiner03668a42009-06-16 15:32:34 -07003338
Rik van Riel28b2ee22008-07-23 21:27:05 -07003339 if ((flags & FOLL_WRITE) && !pte_write(pte))
3340 goto unlock;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003341
3342 *prot = pgprot_val(pte_pgprot(pte));
Johannes Weiner03668a42009-06-16 15:32:34 -07003343 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003344
Johannes Weiner03668a42009-06-16 15:32:34 -07003345 ret = 0;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003346unlock:
3347 pte_unmap_unlock(ptep, ptl);
3348out:
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003349 return ret;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003350}
3351
3352int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3353 void *buf, int len, int write)
3354{
3355 resource_size_t phys_addr;
3356 unsigned long prot = 0;
KOSAKI Motohiro2bc72732009-01-06 14:39:43 -08003357 void __iomem *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003358 int offset = addr & (PAGE_SIZE-1);
3359
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003360 if (follow_phys(vma, addr, write, &prot, &phys_addr))
Rik van Riel28b2ee22008-07-23 21:27:05 -07003361 return -EINVAL;
3362
3363 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3364 if (write)
3365 memcpy_toio(maddr + offset, buf, len);
3366 else
3367 memcpy_fromio(buf, maddr + offset, len);
3368 iounmap(maddr);
3369
3370 return len;
3371}
3372#endif
3373
David Howells0ec76a12006-09-27 01:50:15 -07003374/*
3375 * Access another process' address space.
3376 * Source/target buffer must be kernel space,
3377 * Do not walk the page table directly, use get_user_pages
3378 */
3379int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
3380{
3381 struct mm_struct *mm;
3382 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07003383 void *old_buf = buf;
3384
3385 mm = get_task_mm(tsk);
3386 if (!mm)
3387 return 0;
3388
3389 down_read(&mm->mmap_sem);
Simon Arlott183ff222007-10-20 01:27:18 +02003390 /* ignore errors, just check how much was successfully transferred */
David Howells0ec76a12006-09-27 01:50:15 -07003391 while (len) {
3392 int bytes, ret, offset;
3393 void *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003394 struct page *page = NULL;
David Howells0ec76a12006-09-27 01:50:15 -07003395
3396 ret = get_user_pages(tsk, mm, addr, 1,
3397 write, 1, &page, &vma);
Rik van Riel28b2ee22008-07-23 21:27:05 -07003398 if (ret <= 0) {
3399 /*
3400 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3401 * we can access using slightly different code.
3402 */
3403#ifdef CONFIG_HAVE_IOREMAP_PROT
3404 vma = find_vma(mm, addr);
3405 if (!vma)
3406 break;
3407 if (vma->vm_ops && vma->vm_ops->access)
3408 ret = vma->vm_ops->access(vma, addr, buf,
3409 len, write);
3410 if (ret <= 0)
3411#endif
3412 break;
3413 bytes = ret;
David Howells0ec76a12006-09-27 01:50:15 -07003414 } else {
Rik van Riel28b2ee22008-07-23 21:27:05 -07003415 bytes = len;
3416 offset = addr & (PAGE_SIZE-1);
3417 if (bytes > PAGE_SIZE-offset)
3418 bytes = PAGE_SIZE-offset;
3419
3420 maddr = kmap(page);
3421 if (write) {
3422 copy_to_user_page(vma, page, addr,
3423 maddr + offset, buf, bytes);
3424 set_page_dirty_lock(page);
3425 } else {
3426 copy_from_user_page(vma, page, addr,
3427 buf, maddr + offset, bytes);
3428 }
3429 kunmap(page);
3430 page_cache_release(page);
David Howells0ec76a12006-09-27 01:50:15 -07003431 }
David Howells0ec76a12006-09-27 01:50:15 -07003432 len -= bytes;
3433 buf += bytes;
3434 addr += bytes;
3435 }
3436 up_read(&mm->mmap_sem);
3437 mmput(mm);
3438
3439 return buf - old_buf;
3440}
Andi Kleen03252912008-01-30 13:33:18 +01003441
3442/*
3443 * Print the name of a VMA.
3444 */
3445void print_vma_addr(char *prefix, unsigned long ip)
3446{
3447 struct mm_struct *mm = current->mm;
3448 struct vm_area_struct *vma;
3449
Ingo Molnare8bff742008-02-13 20:21:06 +01003450 /*
3451 * Do not print if we are in atomic
3452 * contexts (in exception stacks, etc.):
3453 */
3454 if (preempt_count())
3455 return;
3456
Andi Kleen03252912008-01-30 13:33:18 +01003457 down_read(&mm->mmap_sem);
3458 vma = find_vma(mm, ip);
3459 if (vma && vma->vm_file) {
3460 struct file *f = vma->vm_file;
3461 char *buf = (char *)__get_free_page(GFP_KERNEL);
3462 if (buf) {
3463 char *p, *s;
3464
Jan Blunckcf28b482008-02-14 19:38:44 -08003465 p = d_path(&f->f_path, buf, PAGE_SIZE);
Andi Kleen03252912008-01-30 13:33:18 +01003466 if (IS_ERR(p))
3467 p = "?";
3468 s = strrchr(p, '/');
3469 if (s)
3470 p = s+1;
3471 printk("%s%s[%lx+%lx]", prefix, p,
3472 vma->vm_start,
3473 vma->vm_end - vma->vm_start);
3474 free_page((unsigned long)buf);
3475 }
3476 }
3477 up_read(&current->mm->mmap_sem);
3478}
Nick Piggin3ee1afa2008-09-10 13:37:17 +02003479
3480#ifdef CONFIG_PROVE_LOCKING
3481void might_fault(void)
3482{
Peter Zijlstra95156f02009-01-12 13:02:11 +01003483 /*
3484 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3485 * holding the mmap_sem, this is safe because kernel memory doesn't
3486 * get paged out, therefore we'll never actually fault, and the
3487 * below annotations will generate false positives.
3488 */
3489 if (segment_eq(get_fs(), KERNEL_DS))
3490 return;
3491
Nick Piggin3ee1afa2008-09-10 13:37:17 +02003492 might_sleep();
3493 /*
3494 * it would be nicer only to annotate paths which are not under
3495 * pagefault_disable, however that requires a larger audit and
3496 * providing helpers like get_user_atomic.
3497 */
3498 if (!in_atomic() && current->mm)
3499 might_lock_read(&current->mm->mmap_sem);
3500}
3501EXPORT_SYMBOL(might_fault);
3502#endif