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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
193void sync_mm_rss(struct task_struct *task, struct mm_struct *mm)
194{
195}
196#endif
197
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198/*
199 * If a p?d_bad entry is found while walking page tables, report
200 * the error, before resetting entry to p?d_none. Usually (but
201 * very seldom) called out from the p?d_none_or_clear_bad macros.
202 */
203
204void pgd_clear_bad(pgd_t *pgd)
205{
206 pgd_ERROR(*pgd);
207 pgd_clear(pgd);
208}
209
210void pud_clear_bad(pud_t *pud)
211{
212 pud_ERROR(*pud);
213 pud_clear(pud);
214}
215
216void pmd_clear_bad(pmd_t *pmd)
217{
218 pmd_ERROR(*pmd);
219 pmd_clear(pmd);
220}
221
222/*
223 * Note: this doesn't free the actual pages themselves. That
224 * has been handled earlier when unmapping all the memory regions.
225 */
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000226static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
227 unsigned long addr)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800229 pgtable_t token = pmd_pgtable(*pmd);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700230 pmd_clear(pmd);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000231 pte_free_tlb(tlb, token, addr);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700232 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700233}
234
Hugh Dickinse0da3822005-04-19 13:29:15 -0700235static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
236 unsigned long addr, unsigned long end,
237 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238{
239 pmd_t *pmd;
240 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700241 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242
Hugh Dickinse0da3822005-04-19 13:29:15 -0700243 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245 do {
246 next = pmd_addr_end(addr, end);
247 if (pmd_none_or_clear_bad(pmd))
248 continue;
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000249 free_pte_range(tlb, pmd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700250 } while (pmd++, addr = next, addr != end);
251
Hugh Dickinse0da3822005-04-19 13:29:15 -0700252 start &= PUD_MASK;
253 if (start < floor)
254 return;
255 if (ceiling) {
256 ceiling &= PUD_MASK;
257 if (!ceiling)
258 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700260 if (end - 1 > ceiling - 1)
261 return;
262
263 pmd = pmd_offset(pud, start);
264 pud_clear(pud);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000265 pmd_free_tlb(tlb, pmd, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266}
267
Hugh Dickinse0da3822005-04-19 13:29:15 -0700268static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
269 unsigned long addr, unsigned long end,
270 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271{
272 pud_t *pud;
273 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700274 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275
Hugh Dickinse0da3822005-04-19 13:29:15 -0700276 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 do {
279 next = pud_addr_end(addr, end);
280 if (pud_none_or_clear_bad(pud))
281 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700282 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 } while (pud++, addr = next, addr != end);
284
Hugh Dickinse0da3822005-04-19 13:29:15 -0700285 start &= PGDIR_MASK;
286 if (start < floor)
287 return;
288 if (ceiling) {
289 ceiling &= PGDIR_MASK;
290 if (!ceiling)
291 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700293 if (end - 1 > ceiling - 1)
294 return;
295
296 pud = pud_offset(pgd, start);
297 pgd_clear(pgd);
Benjamin Herrenschmidt9e1b32c2009-07-22 15:44:28 +1000298 pud_free_tlb(tlb, pud, start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299}
300
301/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700302 * This function frees user-level page tables of a process.
303 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 * Must be called with pagetable lock held.
305 */
Jan Beulich42b77722008-07-23 21:27:10 -0700306void free_pgd_range(struct mmu_gather *tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700307 unsigned long addr, unsigned long end,
308 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309{
310 pgd_t *pgd;
311 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700312 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313
Hugh Dickinse0da3822005-04-19 13:29:15 -0700314 /*
315 * The next few lines have given us lots of grief...
316 *
317 * Why are we testing PMD* at this top level? Because often
318 * there will be no work to do at all, and we'd prefer not to
319 * go all the way down to the bottom just to discover that.
320 *
321 * Why all these "- 1"s? Because 0 represents both the bottom
322 * of the address space and the top of it (using -1 for the
323 * top wouldn't help much: the masks would do the wrong thing).
324 * The rule is that addr 0 and floor 0 refer to the bottom of
325 * the address space, but end 0 and ceiling 0 refer to the top
326 * Comparisons need to use "end - 1" and "ceiling - 1" (though
327 * that end 0 case should be mythical).
328 *
329 * Wherever addr is brought up or ceiling brought down, we must
330 * be careful to reject "the opposite 0" before it confuses the
331 * subsequent tests. But what about where end is brought down
332 * by PMD_SIZE below? no, end can't go down to 0 there.
333 *
334 * Whereas we round start (addr) and ceiling down, by different
335 * masks at different levels, in order to test whether a table
336 * now has no other vmas using it, so can be freed, we don't
337 * bother to round floor or end up - the tests don't need that.
338 */
339
340 addr &= PMD_MASK;
341 if (addr < floor) {
342 addr += PMD_SIZE;
343 if (!addr)
344 return;
345 }
346 if (ceiling) {
347 ceiling &= PMD_MASK;
348 if (!ceiling)
349 return;
350 }
351 if (end - 1 > ceiling - 1)
352 end -= PMD_SIZE;
353 if (addr > end - 1)
354 return;
355
356 start = addr;
Jan Beulich42b77722008-07-23 21:27:10 -0700357 pgd = pgd_offset(tlb->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 do {
359 next = pgd_addr_end(addr, end);
360 if (pgd_none_or_clear_bad(pgd))
361 continue;
Jan Beulich42b77722008-07-23 21:27:10 -0700362 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700364}
365
Jan Beulich42b77722008-07-23 21:27:10 -0700366void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700367 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700368{
369 while (vma) {
370 struct vm_area_struct *next = vma->vm_next;
371 unsigned long addr = vma->vm_start;
372
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700373 /*
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +1000374 * Hide vma from rmap and truncate_pagecache before freeing
375 * pgtables
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700376 */
Rik van Riel5beb4932010-03-05 13:42:07 -0800377 unlink_anon_vmas(vma);
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700378 unlink_file_vma(vma);
379
David Gibson9da61ae2006-03-22 00:08:57 -0800380 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700381 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700382 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700383 } else {
384 /*
385 * Optimization: gather nearby vmas into one call down
386 */
387 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800388 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700389 vma = next;
390 next = vma->vm_next;
Rik van Riel5beb4932010-03-05 13:42:07 -0800391 unlink_anon_vmas(vma);
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700392 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700393 }
394 free_pgd_range(tlb, addr, vma->vm_end,
395 floor, next? next->vm_start: ceiling);
396 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700397 vma = next;
398 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399}
400
Hugh Dickins1bb36302005-10-29 18:16:22 -0700401int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700402{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800403 pgtable_t new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700404 if (!new)
405 return -ENOMEM;
406
Nick Piggin362a61a2008-05-14 06:37:36 +0200407 /*
408 * Ensure all pte setup (eg. pte page lock and page clearing) are
409 * visible before the pte is made visible to other CPUs by being
410 * put into page tables.
411 *
412 * The other side of the story is the pointer chasing in the page
413 * table walking code (when walking the page table without locking;
414 * ie. most of the time). Fortunately, these data accesses consist
415 * of a chain of data-dependent loads, meaning most CPUs (alpha
416 * being the notable exception) will already guarantee loads are
417 * seen in-order. See the alpha page table accessors for the
418 * smp_read_barrier_depends() barriers in page table walking code.
419 */
420 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
421
Hugh Dickinsc74df322005-10-29 18:16:23 -0700422 spin_lock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800423 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 mm->nr_ptes++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 pmd_populate(mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800426 new = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700428 spin_unlock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800429 if (new)
430 pte_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700431 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432}
433
Hugh Dickins1bb36302005-10-29 18:16:22 -0700434int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700436 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
437 if (!new)
438 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
Nick Piggin362a61a2008-05-14 06:37:36 +0200440 smp_wmb(); /* See comment in __pte_alloc */
441
Hugh Dickins1bb36302005-10-29 18:16:22 -0700442 spin_lock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800443 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Hugh Dickins1bb36302005-10-29 18:16:22 -0700444 pmd_populate_kernel(&init_mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800445 new = NULL;
446 }
Hugh Dickins1bb36302005-10-29 18:16:22 -0700447 spin_unlock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800448 if (new)
449 pte_free_kernel(&init_mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700450 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451}
452
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800453static inline void init_rss_vec(int *rss)
Hugh Dickinsae859762005-10-29 18:16:05 -0700454{
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800455 memset(rss, 0, sizeof(int) * NR_MM_COUNTERS);
456}
457
458static inline void add_mm_rss_vec(struct mm_struct *mm, int *rss)
459{
460 int i;
461
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -0800462 if (current->mm == mm)
463 sync_mm_rss(current, mm);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800464 for (i = 0; i < NR_MM_COUNTERS; i++)
465 if (rss[i])
466 add_mm_counter(mm, i, rss[i]);
Hugh Dickinsae859762005-10-29 18:16:05 -0700467}
468
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800470 * This function is called to print an error when a bad pte
471 * is found. For example, we might have a PFN-mapped pte in
472 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700473 *
474 * The calling function must still handle the error.
475 */
Hugh Dickins3dc14742009-01-06 14:40:08 -0800476static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
477 pte_t pte, struct page *page)
Nick Pigginb5810032005-10-29 18:16:12 -0700478{
Hugh Dickins3dc14742009-01-06 14:40:08 -0800479 pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
480 pud_t *pud = pud_offset(pgd, addr);
481 pmd_t *pmd = pmd_offset(pud, addr);
482 struct address_space *mapping;
483 pgoff_t index;
Hugh Dickinsd936cf92009-01-06 14:40:12 -0800484 static unsigned long resume;
485 static unsigned long nr_shown;
486 static unsigned long nr_unshown;
487
488 /*
489 * Allow a burst of 60 reports, then keep quiet for that minute;
490 * or allow a steady drip of one report per second.
491 */
492 if (nr_shown == 60) {
493 if (time_before(jiffies, resume)) {
494 nr_unshown++;
495 return;
496 }
497 if (nr_unshown) {
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800498 printk(KERN_ALERT
499 "BUG: Bad page map: %lu messages suppressed\n",
Hugh Dickinsd936cf92009-01-06 14:40:12 -0800500 nr_unshown);
501 nr_unshown = 0;
502 }
503 nr_shown = 0;
504 }
505 if (nr_shown++ == 0)
506 resume = jiffies + 60 * HZ;
Hugh Dickins3dc14742009-01-06 14:40:08 -0800507
508 mapping = vma->vm_file ? vma->vm_file->f_mapping : NULL;
509 index = linear_page_index(vma, addr);
510
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800511 printk(KERN_ALERT
512 "BUG: Bad page map in process %s pte:%08llx pmd:%08llx\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800513 current->comm,
514 (long long)pte_val(pte), (long long)pmd_val(*pmd));
515 if (page) {
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800516 printk(KERN_ALERT
Hugh Dickins3dc14742009-01-06 14:40:08 -0800517 "page:%p flags:%p count:%d mapcount:%d mapping:%p index:%lx\n",
518 page, (void *)page->flags, page_count(page),
519 page_mapcount(page), page->mapping, page->index);
520 }
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800521 printk(KERN_ALERT
Hugh Dickins3dc14742009-01-06 14:40:08 -0800522 "addr:%p vm_flags:%08lx anon_vma:%p mapping:%p index:%lx\n",
523 (void *)addr, vma->vm_flags, vma->anon_vma, mapping, index);
524 /*
525 * Choose text because data symbols depend on CONFIG_KALLSYMS_ALL=y
526 */
527 if (vma->vm_ops)
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800528 print_symbol(KERN_ALERT "vma->vm_ops->fault: %s\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800529 (unsigned long)vma->vm_ops->fault);
530 if (vma->vm_file && vma->vm_file->f_op)
Hugh Dickins1e9e6362009-01-06 14:40:13 -0800531 print_symbol(KERN_ALERT "vma->vm_file->f_op->mmap: %s\n",
Hugh Dickins3dc14742009-01-06 14:40:08 -0800532 (unsigned long)vma->vm_file->f_op->mmap);
Nick Pigginb5810032005-10-29 18:16:12 -0700533 dump_stack();
Hugh Dickins3dc14742009-01-06 14:40:08 -0800534 add_taint(TAINT_BAD_PAGE);
Nick Pigginb5810032005-10-29 18:16:12 -0700535}
536
Linus Torvalds67121172005-12-11 20:38:17 -0800537static inline int is_cow_mapping(unsigned int flags)
538{
539 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
540}
541
Hugh Dickins62eede62009-09-21 17:03:34 -0700542#ifndef is_zero_pfn
543static inline int is_zero_pfn(unsigned long pfn)
544{
545 return pfn == zero_pfn;
546}
547#endif
548
549#ifndef my_zero_pfn
550static inline unsigned long my_zero_pfn(unsigned long addr)
551{
552 return zero_pfn;
553}
554#endif
555
Nick Pigginb5810032005-10-29 18:16:12 -0700556/*
Nick Piggin7e675132008-04-28 02:13:00 -0700557 * vm_normal_page -- This function gets the "struct page" associated with a pte.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800558 *
Nick Piggin7e675132008-04-28 02:13:00 -0700559 * "Special" mappings do not wish to be associated with a "struct page" (either
560 * it doesn't exist, or it exists but they don't want to touch it). In this
561 * case, NULL is returned here. "Normal" mappings do have a struct page.
Jared Hulbertb379d792008-04-28 02:12:58 -0700562 *
Nick Piggin7e675132008-04-28 02:13:00 -0700563 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
564 * pte bit, in which case this function is trivial. Secondly, an architecture
565 * may not have a spare pte bit, which requires a more complicated scheme,
566 * described below.
567 *
568 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
569 * special mapping (even if there are underlying and valid "struct pages").
570 * COWed pages of a VM_PFNMAP are always normal.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800571 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700572 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
573 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
Nick Piggin7e675132008-04-28 02:13:00 -0700574 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
575 * mapping will always honor the rule
Linus Torvalds6aab3412005-11-28 14:34:23 -0800576 *
577 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
578 *
Nick Piggin7e675132008-04-28 02:13:00 -0700579 * And for normal mappings this is false.
Jared Hulbertb379d792008-04-28 02:12:58 -0700580 *
Nick Piggin7e675132008-04-28 02:13:00 -0700581 * This restricts such mappings to be a linear translation from virtual address
582 * to pfn. To get around this restriction, we allow arbitrary mappings so long
583 * as the vma is not a COW mapping; in that case, we know that all ptes are
584 * special (because none can have been COWed).
Jared Hulbertb379d792008-04-28 02:12:58 -0700585 *
586 *
Nick Piggin7e675132008-04-28 02:13:00 -0700587 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
588 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700589 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
590 * page" backing, however the difference is that _all_ pages with a struct
591 * page (that is, those where pfn_valid is true) are refcounted and considered
592 * normal pages by the VM. The disadvantage is that pages are refcounted
593 * (which can be slower and simply not an option for some PFNMAP users). The
594 * advantage is that we don't have to follow the strict linearity rule of
595 * PFNMAP mappings in order to support COWable mappings.
596 *
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800597 */
Nick Piggin7e675132008-04-28 02:13:00 -0700598#ifdef __HAVE_ARCH_PTE_SPECIAL
599# define HAVE_PTE_SPECIAL 1
600#else
601# define HAVE_PTE_SPECIAL 0
602#endif
603struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
604 pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800605{
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800606 unsigned long pfn = pte_pfn(pte);
Nick Piggin7e675132008-04-28 02:13:00 -0700607
608 if (HAVE_PTE_SPECIAL) {
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800609 if (likely(!pte_special(pte)))
610 goto check_pfn;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -0700611 if (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))
612 return NULL;
Hugh Dickins62eede62009-09-21 17:03:34 -0700613 if (!is_zero_pfn(pfn))
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800614 print_bad_pte(vma, addr, pte, NULL);
Nick Piggin7e675132008-04-28 02:13:00 -0700615 return NULL;
616 }
617
618 /* !HAVE_PTE_SPECIAL case follows: */
619
Jared Hulbertb379d792008-04-28 02:12:58 -0700620 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
621 if (vma->vm_flags & VM_MIXEDMAP) {
622 if (!pfn_valid(pfn))
623 return NULL;
624 goto out;
625 } else {
Nick Piggin7e675132008-04-28 02:13:00 -0700626 unsigned long off;
627 off = (addr - vma->vm_start) >> PAGE_SHIFT;
Jared Hulbertb379d792008-04-28 02:12:58 -0700628 if (pfn == vma->vm_pgoff + off)
629 return NULL;
630 if (!is_cow_mapping(vma->vm_flags))
631 return NULL;
632 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800633 }
634
Hugh Dickins62eede62009-09-21 17:03:34 -0700635 if (is_zero_pfn(pfn))
636 return NULL;
Hugh Dickins22b31ee2009-01-06 14:40:09 -0800637check_pfn:
638 if (unlikely(pfn > highest_memmap_pfn)) {
639 print_bad_pte(vma, addr, pte, NULL);
640 return NULL;
641 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800642
643 /*
Nick Piggin7e675132008-04-28 02:13:00 -0700644 * NOTE! We still have PageReserved() pages in the page tables.
Nick Piggin7e675132008-04-28 02:13:00 -0700645 * eg. VDSO mappings can cause them to exist.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800646 */
Jared Hulbertb379d792008-04-28 02:12:58 -0700647out:
Linus Torvalds6aab3412005-11-28 14:34:23 -0800648 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800649}
650
651/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 * copy one vm_area from one task to the other. Assumes the page tables
653 * already present in the new task to be cleared in the whole range
654 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700655 */
656
Hugh Dickins570a3352009-12-14 17:58:46 -0800657static inline unsigned long
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700659 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700660 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700661{
Nick Pigginb5810032005-10-29 18:16:12 -0700662 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 pte_t pte = *src_pte;
664 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665
666 /* pte contains position in swap or file, so copy. */
667 if (unlikely(!pte_present(pte))) {
668 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700669 swp_entry_t entry = pte_to_swp_entry(pte);
670
Hugh Dickins570a3352009-12-14 17:58:46 -0800671 if (swap_duplicate(entry) < 0)
672 return entry.val;
673
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 /* make sure dst_mm is on swapoff's mmlist. */
675 if (unlikely(list_empty(&dst_mm->mmlist))) {
676 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700677 if (list_empty(&dst_mm->mmlist))
678 list_add(&dst_mm->mmlist,
679 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 spin_unlock(&mmlist_lock);
681 }
KAMEZAWA Hiroyukib084d432010-03-05 13:41:42 -0800682 if (likely(!non_swap_entry(entry)))
683 rss[MM_SWAPENTS]++;
684 else if (is_write_migration_entry(entry) &&
Christoph Lameter06972122006-06-23 02:03:35 -0700685 is_cow_mapping(vm_flags)) {
686 /*
687 * COW mappings require pages in both parent
688 * and child to be set to read.
689 */
690 make_migration_entry_read(&entry);
691 pte = swp_entry_to_pte(entry);
692 set_pte_at(src_mm, addr, src_pte, pte);
693 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700695 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 }
697
Linus Torvalds1da177e2005-04-16 15:20:36 -0700698 /*
699 * If it's a COW mapping, write protect it both
700 * in the parent and the child
701 */
Linus Torvalds67121172005-12-11 20:38:17 -0800702 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 ptep_set_wrprotect(src_mm, addr, src_pte);
Zachary Amsden3dc90792006-09-30 23:29:30 -0700704 pte = pte_wrprotect(pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 }
706
707 /*
708 * If it's a shared mapping, mark it clean in
709 * the child
710 */
711 if (vm_flags & VM_SHARED)
712 pte = pte_mkclean(pte);
713 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800714
715 page = vm_normal_page(vma, addr, pte);
716 if (page) {
717 get_page(page);
Hugh Dickins21333b22009-09-21 17:01:59 -0700718 page_dup_rmap(page);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800719 if (PageAnon(page))
720 rss[MM_ANONPAGES]++;
721 else
722 rss[MM_FILEPAGES]++;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800723 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700724
725out_set_pte:
726 set_pte_at(dst_mm, addr, dst_pte, pte);
Hugh Dickins570a3352009-12-14 17:58:46 -0800727 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728}
729
730static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
731 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
732 unsigned long addr, unsigned long end)
733{
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700734 pte_t *orig_src_pte, *orig_dst_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700736 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700737 int progress = 0;
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800738 int rss[NR_MM_COUNTERS];
Hugh Dickins570a3352009-12-14 17:58:46 -0800739 swp_entry_t entry = (swp_entry_t){0};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
741again:
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800742 init_rss_vec(rss);
743
Hugh Dickinsc74df322005-10-29 18:16:23 -0700744 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 if (!dst_pte)
746 return -ENOMEM;
747 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700748 src_ptl = pte_lockptr(src_mm, src_pmd);
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700749 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700750 orig_src_pte = src_pte;
751 orig_dst_pte = dst_pte;
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700752 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700753
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 do {
755 /*
756 * We are holding two locks at this point - either of them
757 * could generate latencies in another task on another CPU.
758 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700759 if (progress >= 32) {
760 progress = 0;
761 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100762 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700763 break;
764 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 if (pte_none(*src_pte)) {
766 progress++;
767 continue;
768 }
Hugh Dickins570a3352009-12-14 17:58:46 -0800769 entry.val = copy_one_pte(dst_mm, src_mm, dst_pte, src_pte,
770 vma, addr, rss);
771 if (entry.val)
772 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 progress += 8;
774 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700776 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -0700777 spin_unlock(src_ptl);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700778 pte_unmap_nested(orig_src_pte);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800779 add_mm_rss_vec(dst_mm, rss);
Daisuke Nishimurac36987e2009-10-26 16:50:23 -0700780 pte_unmap_unlock(orig_dst_pte, dst_ptl);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700781 cond_resched();
Hugh Dickins570a3352009-12-14 17:58:46 -0800782
783 if (entry.val) {
784 if (add_swap_count_continuation(entry, GFP_KERNEL) < 0)
785 return -ENOMEM;
786 progress = 0;
787 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 if (addr != end)
789 goto again;
790 return 0;
791}
792
793static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
794 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
795 unsigned long addr, unsigned long end)
796{
797 pmd_t *src_pmd, *dst_pmd;
798 unsigned long next;
799
800 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
801 if (!dst_pmd)
802 return -ENOMEM;
803 src_pmd = pmd_offset(src_pud, addr);
804 do {
805 next = pmd_addr_end(addr, end);
806 if (pmd_none_or_clear_bad(src_pmd))
807 continue;
808 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
809 vma, addr, next))
810 return -ENOMEM;
811 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
812 return 0;
813}
814
815static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
816 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
817 unsigned long addr, unsigned long end)
818{
819 pud_t *src_pud, *dst_pud;
820 unsigned long next;
821
822 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
823 if (!dst_pud)
824 return -ENOMEM;
825 src_pud = pud_offset(src_pgd, addr);
826 do {
827 next = pud_addr_end(addr, end);
828 if (pud_none_or_clear_bad(src_pud))
829 continue;
830 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
831 vma, addr, next))
832 return -ENOMEM;
833 } while (dst_pud++, src_pud++, addr = next, addr != end);
834 return 0;
835}
836
837int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
838 struct vm_area_struct *vma)
839{
840 pgd_t *src_pgd, *dst_pgd;
841 unsigned long next;
842 unsigned long addr = vma->vm_start;
843 unsigned long end = vma->vm_end;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700844 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
Nick Piggind9928952005-08-28 16:49:11 +1000846 /*
847 * Don't copy ptes where a page fault will fill them correctly.
848 * Fork becomes much lighter when there are big shared or private
849 * readonly mappings. The tradeoff is that copy_page_range is more
850 * efficient than faulting.
851 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800852 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000853 if (!vma->anon_vma)
854 return 0;
855 }
856
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 if (is_vm_hugetlb_page(vma))
858 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
859
venkatesh.pallipadi@intel.com34801ba2008-12-19 13:47:29 -0800860 if (unlikely(is_pfn_mapping(vma))) {
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -0800861 /*
862 * We do not free on error cases below as remove_vma
863 * gets called on error from higher level routine
864 */
865 ret = track_pfn_vma_copy(vma);
866 if (ret)
867 return ret;
868 }
869
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700870 /*
871 * We need to invalidate the secondary MMU mappings only when
872 * there could be a permission downgrade on the ptes of the
873 * parent mm. And a permission downgrade will only happen if
874 * is_cow_mapping() returns true.
875 */
876 if (is_cow_mapping(vma->vm_flags))
877 mmu_notifier_invalidate_range_start(src_mm, addr, end);
878
879 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 dst_pgd = pgd_offset(dst_mm, addr);
881 src_pgd = pgd_offset(src_mm, addr);
882 do {
883 next = pgd_addr_end(addr, end);
884 if (pgd_none_or_clear_bad(src_pgd))
885 continue;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700886 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
887 vma, addr, next))) {
888 ret = -ENOMEM;
889 break;
890 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700892
893 if (is_cow_mapping(vma->vm_flags))
894 mmu_notifier_invalidate_range_end(src_mm,
895 vma->vm_start, end);
896 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897}
898
Robin Holt51c6f662005-11-13 16:06:42 -0800899static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700900 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800902 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903{
Nick Pigginb5810032005-10-29 18:16:12 -0700904 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700906 spinlock_t *ptl;
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800907 int rss[NR_MM_COUNTERS];
908
909 init_rss_vec(rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910
Hugh Dickins508034a2005-10-29 18:16:30 -0700911 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700912 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700913 do {
914 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800915 if (pte_none(ptent)) {
916 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700917 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800918 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800919
920 (*zap_work) -= PAGE_SIZE;
921
Linus Torvalds1da177e2005-04-16 15:20:36 -0700922 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800923 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800924
Linus Torvalds6aab3412005-11-28 14:34:23 -0800925 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 if (unlikely(details) && page) {
927 /*
928 * unmap_shared_mapping_pages() wants to
929 * invalidate cache without truncating:
930 * unmap shared but keep private pages.
931 */
932 if (details->check_mapping &&
933 details->check_mapping != page->mapping)
934 continue;
935 /*
936 * Each page->index must be checked when
937 * invalidating or truncating nonlinear.
938 */
939 if (details->nonlinear_vma &&
940 (page->index < details->first_index ||
941 page->index > details->last_index))
942 continue;
943 }
Nick Pigginb5810032005-10-29 18:16:12 -0700944 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700945 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946 tlb_remove_tlb_entry(tlb, pte, addr);
947 if (unlikely(!page))
948 continue;
949 if (unlikely(details) && details->nonlinear_vma
950 && linear_page_index(details->nonlinear_vma,
951 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700952 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 if (PageAnon(page))
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800955 rss[MM_ANONPAGES]--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700956 else {
957 if (pte_dirty(ptent))
958 set_page_dirty(page);
Johannes Weiner4917e5d2009-01-06 14:39:17 -0800959 if (pte_young(ptent) &&
960 likely(!VM_SequentialReadHint(vma)))
Nick Pigginbf3f3bc2009-01-06 14:38:55 -0800961 mark_page_accessed(page);
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800962 rss[MM_FILEPAGES]--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700963 }
Hugh Dickinsedc315f2009-01-06 14:40:11 -0800964 page_remove_rmap(page);
Hugh Dickins3dc14742009-01-06 14:40:08 -0800965 if (unlikely(page_mapcount(page) < 0))
966 print_bad_pte(vma, addr, ptent, page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 tlb_remove_page(tlb, page);
968 continue;
969 }
970 /*
971 * If details->check_mapping, we leave swap entries;
972 * if details->nonlinear_vma, we leave file entries.
973 */
974 if (unlikely(details))
975 continue;
Hugh Dickins2509ef22009-01-06 14:40:10 -0800976 if (pte_file(ptent)) {
977 if (unlikely(!(vma->vm_flags & VM_NONLINEAR)))
978 print_bad_pte(vma, addr, ptent, NULL);
KAMEZAWA Hiroyukib084d432010-03-05 13:41:42 -0800979 } else {
980 swp_entry_t entry = pte_to_swp_entry(ptent);
981
982 if (!non_swap_entry(entry))
983 rss[MM_SWAPENTS]--;
984 if (unlikely(!free_swap_and_cache(entry)))
985 print_bad_pte(vma, addr, ptent, NULL);
986 }
Zachary Amsden9888a1c2006-09-30 23:29:31 -0700987 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800988 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700989
KAMEZAWA Hiroyukid559db02010-03-05 13:41:39 -0800990 add_mm_rss_vec(mm, rss);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700991 arch_leave_lazy_mmu_mode();
Hugh Dickins508034a2005-10-29 18:16:30 -0700992 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800993
994 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995}
996
Robin Holt51c6f662005-11-13 16:06:42 -0800997static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700998 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -08001000 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001001{
1002 pmd_t *pmd;
1003 unsigned long next;
1004
1005 pmd = pmd_offset(pud, addr);
1006 do {
1007 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -08001008 if (pmd_none_or_clear_bad(pmd)) {
1009 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010 continue;
Robin Holt51c6f662005-11-13 16:06:42 -08001011 }
1012 next = zap_pte_range(tlb, vma, pmd, addr, next,
1013 zap_work, details);
1014 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
1015
1016 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001017}
1018
Robin Holt51c6f662005-11-13 16:06:42 -08001019static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -07001020 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001021 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -08001022 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023{
1024 pud_t *pud;
1025 unsigned long next;
1026
1027 pud = pud_offset(pgd, addr);
1028 do {
1029 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -08001030 if (pud_none_or_clear_bad(pud)) {
1031 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001032 continue;
Robin Holt51c6f662005-11-13 16:06:42 -08001033 }
1034 next = zap_pmd_range(tlb, vma, pud, addr, next,
1035 zap_work, details);
1036 } while (pud++, addr = next, (addr != end && *zap_work > 0));
1037
1038 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039}
1040
Robin Holt51c6f662005-11-13 16:06:42 -08001041static unsigned long unmap_page_range(struct mmu_gather *tlb,
1042 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -08001044 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045{
1046 pgd_t *pgd;
1047 unsigned long next;
1048
1049 if (details && !details->check_mapping && !details->nonlinear_vma)
1050 details = NULL;
1051
1052 BUG_ON(addr >= end);
KAMEZAWA Hiroyuki569b8462009-12-15 16:47:03 -08001053 mem_cgroup_uncharge_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001054 tlb_start_vma(tlb, vma);
1055 pgd = pgd_offset(vma->vm_mm, addr);
1056 do {
1057 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -08001058 if (pgd_none_or_clear_bad(pgd)) {
1059 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001060 continue;
Robin Holt51c6f662005-11-13 16:06:42 -08001061 }
1062 next = zap_pud_range(tlb, vma, pgd, addr, next,
1063 zap_work, details);
1064 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065 tlb_end_vma(tlb, vma);
KAMEZAWA Hiroyuki569b8462009-12-15 16:47:03 -08001066 mem_cgroup_uncharge_end();
Robin Holt51c6f662005-11-13 16:06:42 -08001067
1068 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069}
1070
1071#ifdef CONFIG_PREEMPT
1072# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
1073#else
1074/* No preempt: go for improved straight-line efficiency */
1075# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
1076#endif
1077
1078/**
1079 * unmap_vmas - unmap a range of memory covered by a list of vma's
1080 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -07001081 * @vma: the starting vma
1082 * @start_addr: virtual address at which to start unmapping
1083 * @end_addr: virtual address at which to end unmapping
1084 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
1085 * @details: details of nonlinear truncation or shared cache invalidation
1086 *
Hugh Dickinsee39b372005-04-19 13:29:15 -07001087 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088 *
Hugh Dickins508034a2005-10-29 18:16:30 -07001089 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 *
Hugh Dickins508034a2005-10-29 18:16:30 -07001091 * We aim to not hold locks for too long (for scheduling latency reasons).
1092 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093 * return the ending mmu_gather to the caller.
1094 *
1095 * Only addresses between `start' and `end' will be unmapped.
1096 *
1097 * The VMA list must be sorted in ascending virtual address order.
1098 *
1099 * unmap_vmas() assumes that the caller will flush the whole unmapped address
1100 * range after unmap_vmas() returns. So the only responsibility here is to
1101 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
1102 * drops the lock and schedules.
1103 */
Hugh Dickins508034a2005-10-29 18:16:30 -07001104unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001105 struct vm_area_struct *vma, unsigned long start_addr,
1106 unsigned long end_addr, unsigned long *nr_accounted,
1107 struct zap_details *details)
1108{
Robin Holt51c6f662005-11-13 16:06:42 -08001109 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001110 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
1111 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -07001112 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001113 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -07001114 int fullmm = (*tlbp)->fullmm;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001115 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001116
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001117 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001118 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001119 unsigned long end;
1120
1121 start = max(vma->vm_start, start_addr);
1122 if (start >= vma->vm_end)
1123 continue;
1124 end = min(vma->vm_end, end_addr);
1125 if (end <= vma->vm_start)
1126 continue;
1127
1128 if (vma->vm_flags & VM_ACCOUNT)
1129 *nr_accounted += (end - start) >> PAGE_SHIFT;
1130
venkatesh.pallipadi@intel.com34801ba2008-12-19 13:47:29 -08001131 if (unlikely(is_pfn_mapping(vma)))
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001132 untrack_pfn_vma(vma, 0, 0);
1133
Linus Torvalds1da177e2005-04-16 15:20:36 -07001134 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001135 if (!tlb_start_valid) {
1136 tlb_start = start;
1137 tlb_start_valid = 1;
1138 }
1139
Robin Holt51c6f662005-11-13 16:06:42 -08001140 if (unlikely(is_vm_hugetlb_page(vma))) {
Andi Kleena137e1c2008-07-23 21:27:43 -07001141 /*
1142 * It is undesirable to test vma->vm_file as it
1143 * should be non-null for valid hugetlb area.
1144 * However, vm_file will be NULL in the error
1145 * cleanup path of do_mmap_pgoff. When
1146 * hugetlbfs ->mmap method fails,
1147 * do_mmap_pgoff() nullifies vma->vm_file
1148 * before calling this function to clean up.
1149 * Since no pte has actually been setup, it is
1150 * safe to do nothing in this case.
1151 */
1152 if (vma->vm_file) {
1153 unmap_hugepage_range(vma, start, end, NULL);
1154 zap_work -= (end - start) /
Andi Kleena5516432008-07-23 21:27:41 -07001155 pages_per_huge_page(hstate_vma(vma));
Andi Kleena137e1c2008-07-23 21:27:43 -07001156 }
1157
Robin Holt51c6f662005-11-13 16:06:42 -08001158 start = end;
1159 } else
1160 start = unmap_page_range(*tlbp, vma,
1161 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162
Robin Holt51c6f662005-11-13 16:06:42 -08001163 if (zap_work > 0) {
1164 BUG_ON(start != end);
1165 break;
1166 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001167
1168 tlb_finish_mmu(*tlbp, tlb_start, start);
1169
1170 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +01001171 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001172 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -07001173 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001174 goto out;
1175 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 }
1178
Hugh Dickins508034a2005-10-29 18:16:30 -07001179 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001180 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -08001181 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 }
1183 }
1184out:
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001185 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001186 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001187}
1188
1189/**
1190 * zap_page_range - remove user pages in a given range
1191 * @vma: vm_area_struct holding the applicable pages
1192 * @address: starting address of pages to zap
1193 * @size: number of bytes to zap
1194 * @details: details of nonlinear truncation or shared cache invalidation
1195 */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001196unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001197 unsigned long size, struct zap_details *details)
1198{
1199 struct mm_struct *mm = vma->vm_mm;
1200 struct mmu_gather *tlb;
1201 unsigned long end = address + size;
1202 unsigned long nr_accounted = 0;
1203
Linus Torvalds1da177e2005-04-16 15:20:36 -07001204 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001205 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -07001206 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -07001207 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
1208 if (tlb)
1209 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -07001210 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211}
1212
Jack Steinerc627f9c2008-07-29 22:33:53 -07001213/**
1214 * zap_vma_ptes - remove ptes mapping the vma
1215 * @vma: vm_area_struct holding ptes to be zapped
1216 * @address: starting address of pages to zap
1217 * @size: number of bytes to zap
1218 *
1219 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1220 *
1221 * The entire address range must be fully contained within the vma.
1222 *
1223 * Returns 0 if successful.
1224 */
1225int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1226 unsigned long size)
1227{
1228 if (address < vma->vm_start || address + size > vma->vm_end ||
1229 !(vma->vm_flags & VM_PFNMAP))
1230 return -1;
1231 zap_page_range(vma, address, size, NULL);
1232 return 0;
1233}
1234EXPORT_SYMBOL_GPL(zap_vma_ptes);
1235
Linus Torvalds1da177e2005-04-16 15:20:36 -07001236/*
1237 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001238 */
Linus Torvalds6aab3412005-11-28 14:34:23 -08001239struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001240 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001241{
1242 pgd_t *pgd;
1243 pud_t *pud;
1244 pmd_t *pmd;
1245 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001246 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001248 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001250 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1251 if (!IS_ERR(page)) {
1252 BUG_ON(flags & FOLL_GET);
1253 goto out;
1254 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001255
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001256 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 pgd = pgd_offset(mm, address);
1258 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001259 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001260
1261 pud = pud_offset(pgd, address);
Andi Kleenceb86872008-07-23 21:27:50 -07001262 if (pud_none(*pud))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001263 goto no_page_table;
Andi Kleenceb86872008-07-23 21:27:50 -07001264 if (pud_huge(*pud)) {
1265 BUG_ON(flags & FOLL_GET);
1266 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1267 goto out;
1268 }
1269 if (unlikely(pud_bad(*pud)))
1270 goto no_page_table;
1271
Linus Torvalds1da177e2005-04-16 15:20:36 -07001272 pmd = pmd_offset(pud, address);
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001273 if (pmd_none(*pmd))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001274 goto no_page_table;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001275 if (pmd_huge(*pmd)) {
1276 BUG_ON(flags & FOLL_GET);
1277 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1278 goto out;
1279 }
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001280 if (unlikely(pmd_bad(*pmd)))
1281 goto no_page_table;
1282
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001283 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284
1285 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001286 if (!pte_present(pte))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001287 goto no_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001288 if ((flags & FOLL_WRITE) && !pte_write(pte))
1289 goto unlock;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001290
Linus Torvalds6aab3412005-11-28 14:34:23 -08001291 page = vm_normal_page(vma, address, pte);
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001292 if (unlikely(!page)) {
1293 if ((flags & FOLL_DUMP) ||
Hugh Dickins62eede62009-09-21 17:03:34 -07001294 !is_zero_pfn(pte_pfn(pte)))
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07001295 goto bad_page;
1296 page = pte_page(pte);
1297 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001298
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001299 if (flags & FOLL_GET)
1300 get_page(page);
1301 if (flags & FOLL_TOUCH) {
1302 if ((flags & FOLL_WRITE) &&
1303 !pte_dirty(pte) && !PageDirty(page))
1304 set_page_dirty(page);
KOSAKI Motohirobd775c42009-03-31 15:19:37 -07001305 /*
1306 * pte_mkyoung() would be more correct here, but atomic care
1307 * is needed to avoid losing the dirty bit: it is easier to use
1308 * mark_page_accessed().
1309 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001310 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001312unlock:
1313 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001314out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001315 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001316
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001317bad_page:
1318 pte_unmap_unlock(ptep, ptl);
1319 return ERR_PTR(-EFAULT);
1320
1321no_page:
1322 pte_unmap_unlock(ptep, ptl);
1323 if (!pte_none(pte))
1324 return page;
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001325
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001326no_page_table:
1327 /*
1328 * When core dumping an enormous anonymous area that nobody
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001329 * has touched so far, we don't want to allocate unnecessary pages or
1330 * page tables. Return error instead of NULL to skip handle_mm_fault,
1331 * then get_dump_page() will return NULL to leave a hole in the dump.
1332 * But we can only make this optimization where a hole would surely
1333 * be zero-filled if handle_mm_fault() actually did handle it.
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001334 */
Hugh Dickins8e4b9a62009-09-21 17:03:26 -07001335 if ((flags & FOLL_DUMP) &&
1336 (!vma->vm_ops || !vma->vm_ops->fault))
1337 return ERR_PTR(-EFAULT);
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001338 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001339}
1340
Nick Pigginb291f002008-10-18 20:26:44 -07001341int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001342 unsigned long start, int nr_pages, unsigned int gup_flags,
Peter Zijlstra9d737772009-06-25 11:58:55 +02001343 struct page **pages, struct vm_area_struct **vmas)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001344{
1345 int i;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001346 unsigned long vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347
Peter Zijlstra9d737772009-06-25 11:58:55 +02001348 if (nr_pages <= 0)
Jonathan Corbet900cf082008-02-11 16:17:33 -07001349 return 0;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001350
1351 VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
1352
Linus Torvalds1da177e2005-04-16 15:20:36 -07001353 /*
1354 * Require read or write permissions.
Hugh Dickins58fa8792009-09-21 17:03:31 -07001355 * If FOLL_FORCE is set, we only require the "MAY" flags.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356 */
Hugh Dickins58fa8792009-09-21 17:03:31 -07001357 vm_flags = (gup_flags & FOLL_WRITE) ?
1358 (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1359 vm_flags &= (gup_flags & FOLL_FORCE) ?
1360 (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 i = 0;
1362
1363 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001364 struct vm_area_struct *vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001365
1366 vma = find_extend_vma(mm, start);
1367 if (!vma && in_gate_area(tsk, start)) {
1368 unsigned long pg = start & PAGE_MASK;
1369 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1370 pgd_t *pgd;
1371 pud_t *pud;
1372 pmd_t *pmd;
1373 pte_t *pte;
Nick Pigginb291f002008-10-18 20:26:44 -07001374
1375 /* user gate pages are read-only */
Hugh Dickins58fa8792009-09-21 17:03:31 -07001376 if (gup_flags & FOLL_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 return i ? : -EFAULT;
1378 if (pg > TASK_SIZE)
1379 pgd = pgd_offset_k(pg);
1380 else
1381 pgd = pgd_offset_gate(mm, pg);
1382 BUG_ON(pgd_none(*pgd));
1383 pud = pud_offset(pgd, pg);
1384 BUG_ON(pud_none(*pud));
1385 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001386 if (pmd_none(*pmd))
1387 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001388 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001389 if (pte_none(*pte)) {
1390 pte_unmap(pte);
1391 return i ? : -EFAULT;
1392 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001393 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001394 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001395 pages[i] = page;
1396 if (page)
1397 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 }
1399 pte_unmap(pte);
1400 if (vmas)
1401 vmas[i] = gate_vma;
1402 i++;
1403 start += PAGE_SIZE;
Peter Zijlstra9d737772009-06-25 11:58:55 +02001404 nr_pages--;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001405 continue;
1406 }
1407
Nick Pigginb291f002008-10-18 20:26:44 -07001408 if (!vma ||
1409 (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001410 !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001411 return i ? : -EFAULT;
1412
Hugh Dickins2a15efc2009-09-21 17:03:27 -07001413 if (is_vm_hugetlb_page(vma)) {
1414 i = follow_hugetlb_page(mm, vma, pages, vmas,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001415 &start, &nr_pages, i, gup_flags);
Hugh Dickins2a15efc2009-09-21 17:03:27 -07001416 continue;
1417 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001418
Linus Torvalds1da177e2005-04-16 15:20:36 -07001419 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001420 struct page *page;
Hugh Dickins58fa8792009-09-21 17:03:31 -07001421 unsigned int foll_flags = gup_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422
Ethan Solomita462e00c2007-07-15 23:38:16 -07001423 /*
Ying Han47792802009-01-06 14:40:18 -08001424 * If we have a pending SIGKILL, don't keep faulting
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001425 * pages and potentially allocating memory.
Ethan Solomita462e00c2007-07-15 23:38:16 -07001426 */
Hugh Dickins1c3aff12009-09-21 17:03:24 -07001427 if (unlikely(fatal_signal_pending(current)))
Ying Han47792802009-01-06 14:40:18 -08001428 return i ? i : -ERESTARTSYS;
Ethan Solomita462e00c2007-07-15 23:38:16 -07001429
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001430 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001431 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001432 int ret;
Linus Torvaldsd06063c2009-04-10 09:01:23 -07001433
Hugh Dickinsd26ed652009-06-23 13:52:49 +01001434 ret = handle_mm_fault(mm, vma, start,
1435 (foll_flags & FOLL_WRITE) ?
1436 FAULT_FLAG_WRITE : 0);
1437
Nick Piggin83c54072007-07-19 01:47:05 -07001438 if (ret & VM_FAULT_ERROR) {
1439 if (ret & VM_FAULT_OOM)
1440 return i ? i : -ENOMEM;
Andi Kleend1737fd2009-09-16 11:50:06 +02001441 if (ret &
1442 (VM_FAULT_HWPOISON|VM_FAULT_SIGBUS))
Nick Piggin83c54072007-07-19 01:47:05 -07001443 return i ? i : -EFAULT;
1444 BUG();
1445 }
1446 if (ret & VM_FAULT_MAJOR)
1447 tsk->maj_flt++;
1448 else
1449 tsk->min_flt++;
1450
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001451 /*
Nick Piggin83c54072007-07-19 01:47:05 -07001452 * The VM_FAULT_WRITE bit tells us that
1453 * do_wp_page has broken COW when necessary,
1454 * even if maybe_mkwrite decided not to set
1455 * pte_write. We can thus safely do subsequent
Hugh Dickins878b63a2009-01-06 14:39:32 -08001456 * page lookups as if they were reads. But only
1457 * do so when looping for pte_write is futile:
1458 * in some cases userspace may also be wanting
1459 * to write to the gotten user page, which a
1460 * read fault here might prevent (a readonly
1461 * page might get reCOWed by userspace write).
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001462 */
Hugh Dickins878b63a2009-01-06 14:39:32 -08001463 if ((ret & VM_FAULT_WRITE) &&
1464 !(vma->vm_flags & VM_WRITE))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001465 foll_flags &= ~FOLL_WRITE;
Nick Piggin83c54072007-07-19 01:47:05 -07001466
Benjamin Herrenschmidt7f7bbbe2006-10-06 00:43:53 -07001467 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001468 }
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001469 if (IS_ERR(page))
1470 return i ? i : PTR_ERR(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001472 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001473
Russell Kinga6f36be2006-12-30 22:24:19 +00001474 flush_anon_page(vma, page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001475 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001476 }
1477 if (vmas)
1478 vmas[i] = vma;
1479 i++;
1480 start += PAGE_SIZE;
Peter Zijlstra9d737772009-06-25 11:58:55 +02001481 nr_pages--;
1482 } while (nr_pages && start < vma->vm_end);
1483 } while (nr_pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001484 return i;
1485}
Nick Pigginb291f002008-10-18 20:26:44 -07001486
Nick Piggind2bf6be2009-06-16 15:31:39 -07001487/**
1488 * get_user_pages() - pin user pages in memory
1489 * @tsk: task_struct of target task
1490 * @mm: mm_struct of target mm
1491 * @start: starting user address
Peter Zijlstra9d737772009-06-25 11:58:55 +02001492 * @nr_pages: number of pages from start to pin
Nick Piggind2bf6be2009-06-16 15:31:39 -07001493 * @write: whether pages will be written to by the caller
1494 * @force: whether to force write access even if user mapping is
1495 * readonly. This will result in the page being COWed even
1496 * in MAP_SHARED mappings. You do not want this.
1497 * @pages: array that receives pointers to the pages pinned.
1498 * Should be at least nr_pages long. Or NULL, if caller
1499 * only intends to ensure the pages are faulted in.
1500 * @vmas: array of pointers to vmas corresponding to each page.
1501 * Or NULL if the caller does not require them.
1502 *
1503 * Returns number of pages pinned. This may be fewer than the number
Peter Zijlstra9d737772009-06-25 11:58:55 +02001504 * requested. If nr_pages is 0 or negative, returns 0. If no pages
Nick Piggind2bf6be2009-06-16 15:31:39 -07001505 * were pinned, returns -errno. Each page returned must be released
1506 * with a put_page() call when it is finished with. vmas will only
1507 * remain valid while mmap_sem is held.
1508 *
1509 * Must be called with mmap_sem held for read or write.
1510 *
1511 * get_user_pages walks a process's page tables and takes a reference to
1512 * each struct page that each user address corresponds to at a given
1513 * instant. That is, it takes the page that would be accessed if a user
1514 * thread accesses the given user virtual address at that instant.
1515 *
1516 * This does not guarantee that the page exists in the user mappings when
1517 * get_user_pages returns, and there may even be a completely different
1518 * page there in some cases (eg. if mmapped pagecache has been invalidated
1519 * and subsequently re faulted). However it does guarantee that the page
1520 * won't be freed completely. And mostly callers simply care that the page
1521 * contains data that was valid *at some point in time*. Typically, an IO
1522 * or similar operation cannot guarantee anything stronger anyway because
1523 * locks can't be held over the syscall boundary.
1524 *
1525 * If write=0, the page must not be written to. If the page is written to,
1526 * set_page_dirty (or set_page_dirty_lock, as appropriate) must be called
1527 * after the page is finished with, and before put_page is called.
1528 *
1529 * get_user_pages is typically used for fewer-copy IO operations, to get a
1530 * handle on the memory by some means other than accesses via the user virtual
1531 * addresses. The pages may be submitted for DMA to devices or accessed via
1532 * their kernel linear mapping (via the kmap APIs). Care should be taken to
1533 * use the correct cache flushing APIs.
1534 *
1535 * See also get_user_pages_fast, for performance critical applications.
1536 */
Nick Pigginb291f002008-10-18 20:26:44 -07001537int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
Peter Zijlstra9d737772009-06-25 11:58:55 +02001538 unsigned long start, int nr_pages, int write, int force,
Nick Pigginb291f002008-10-18 20:26:44 -07001539 struct page **pages, struct vm_area_struct **vmas)
1540{
Hugh Dickins58fa8792009-09-21 17:03:31 -07001541 int flags = FOLL_TOUCH;
Nick Pigginb291f002008-10-18 20:26:44 -07001542
Hugh Dickins58fa8792009-09-21 17:03:31 -07001543 if (pages)
1544 flags |= FOLL_GET;
Nick Pigginb291f002008-10-18 20:26:44 -07001545 if (write)
Hugh Dickins58fa8792009-09-21 17:03:31 -07001546 flags |= FOLL_WRITE;
Nick Pigginb291f002008-10-18 20:26:44 -07001547 if (force)
Hugh Dickins58fa8792009-09-21 17:03:31 -07001548 flags |= FOLL_FORCE;
Nick Pigginb291f002008-10-18 20:26:44 -07001549
Peter Zijlstra9d737772009-06-25 11:58:55 +02001550 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
Nick Pigginb291f002008-10-18 20:26:44 -07001551}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001552EXPORT_SYMBOL(get_user_pages);
1553
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001554/**
1555 * get_dump_page() - pin user page in memory while writing it to core dump
1556 * @addr: user address
1557 *
1558 * Returns struct page pointer of user page pinned for dump,
1559 * to be freed afterwards by page_cache_release() or put_page().
1560 *
1561 * Returns NULL on any kind of failure - a hole must then be inserted into
1562 * the corefile, to preserve alignment with its headers; and also returns
1563 * NULL wherever the ZERO_PAGE, or an anonymous pte_none, has been found -
1564 * allowing a hole to be left in the corefile to save diskspace.
1565 *
1566 * Called without mmap_sem, but after all other threads have been killed.
1567 */
1568#ifdef CONFIG_ELF_CORE
1569struct page *get_dump_page(unsigned long addr)
1570{
1571 struct vm_area_struct *vma;
1572 struct page *page;
1573
1574 if (__get_user_pages(current, current->mm, addr, 1,
Hugh Dickins58fa8792009-09-21 17:03:31 -07001575 FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001576 return NULL;
Hugh Dickinsf3e8fcc2009-09-21 17:03:25 -07001577 flush_cache_page(vma, addr, page_to_pfn(page));
1578 return page;
1579}
1580#endif /* CONFIG_ELF_CORE */
1581
Harvey Harrison920c7a52008-02-04 22:29:26 -08001582pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1583 spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001584{
1585 pgd_t * pgd = pgd_offset(mm, addr);
1586 pud_t * pud = pud_alloc(mm, pgd, addr);
1587 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001588 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001589 if (pmd)
1590 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1591 }
1592 return NULL;
1593}
1594
Linus Torvalds1da177e2005-04-16 15:20:36 -07001595/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001596 * This is the old fallback for page remapping.
1597 *
1598 * For historical reasons, it only allows reserved pages. Only
1599 * old drivers should use this, and they needed to mark their
1600 * pages reserved for the old functions anyway.
1601 */
Nick Piggin423bad62008-04-28 02:13:01 -07001602static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1603 struct page *page, pgprot_t prot)
Linus Torvalds238f58d2005-11-29 13:01:56 -08001604{
Nick Piggin423bad62008-04-28 02:13:01 -07001605 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001606 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001607 pte_t *pte;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001608 spinlock_t *ptl;
1609
Linus Torvalds238f58d2005-11-29 13:01:56 -08001610 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001611 if (PageAnon(page))
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07001612 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001613 retval = -ENOMEM;
1614 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001615 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001616 if (!pte)
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07001617 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001618 retval = -EBUSY;
1619 if (!pte_none(*pte))
1620 goto out_unlock;
1621
1622 /* Ok, finally just insert the thing.. */
1623 get_page(page);
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08001624 inc_mm_counter_fast(mm, MM_FILEPAGES);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001625 page_add_file_rmap(page);
1626 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1627
1628 retval = 0;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001629 pte_unmap_unlock(pte, ptl);
1630 return retval;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001631out_unlock:
1632 pte_unmap_unlock(pte, ptl);
1633out:
1634 return retval;
1635}
1636
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001637/**
1638 * vm_insert_page - insert single page into user vma
1639 * @vma: user vma to map to
1640 * @addr: target user address of this page
1641 * @page: source kernel page
1642 *
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001643 * This allows drivers to insert individual pages they've allocated
1644 * into a user vma.
1645 *
1646 * The page has to be a nice clean _individual_ kernel allocation.
1647 * If you allocate a compound page, you need to have marked it as
1648 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001649 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001650 *
1651 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1652 * took an arbitrary page protection parameter. This doesn't allow
1653 * that. Your vma protection will have to be set up correctly, which
1654 * means that if you want a shared writable mapping, you'd better
1655 * ask for a shared writable mapping!
1656 *
1657 * The page does not need to be reserved.
1658 */
Nick Piggin423bad62008-04-28 02:13:01 -07001659int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1660 struct page *page)
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001661{
1662 if (addr < vma->vm_start || addr >= vma->vm_end)
1663 return -EFAULT;
1664 if (!page_count(page))
1665 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001666 vma->vm_flags |= VM_INSERTPAGE;
Nick Piggin423bad62008-04-28 02:13:01 -07001667 return insert_page(vma, addr, page, vma->vm_page_prot);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001668}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001669EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001670
Nick Piggin423bad62008-04-28 02:13:01 -07001671static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1672 unsigned long pfn, pgprot_t prot)
1673{
1674 struct mm_struct *mm = vma->vm_mm;
1675 int retval;
1676 pte_t *pte, entry;
1677 spinlock_t *ptl;
1678
1679 retval = -ENOMEM;
1680 pte = get_locked_pte(mm, addr, &ptl);
1681 if (!pte)
1682 goto out;
1683 retval = -EBUSY;
1684 if (!pte_none(*pte))
1685 goto out_unlock;
1686
1687 /* Ok, finally just insert the thing.. */
1688 entry = pte_mkspecial(pfn_pte(pfn, prot));
1689 set_pte_at(mm, addr, pte, entry);
Russell King4b3073e2009-12-18 16:40:18 +00001690 update_mmu_cache(vma, addr, pte); /* XXX: why not for insert_page? */
Nick Piggin423bad62008-04-28 02:13:01 -07001691
1692 retval = 0;
1693out_unlock:
1694 pte_unmap_unlock(pte, ptl);
1695out:
1696 return retval;
1697}
1698
Nick Piggine0dc0d82007-02-12 00:51:36 -08001699/**
1700 * vm_insert_pfn - insert single pfn into user vma
1701 * @vma: user vma to map to
1702 * @addr: target user address of this page
1703 * @pfn: source kernel pfn
1704 *
1705 * Similar to vm_inert_page, this allows drivers to insert individual pages
1706 * they've allocated into a user vma. Same comments apply.
1707 *
1708 * This function should only be called from a vm_ops->fault handler, and
1709 * in that case the handler should return NULL.
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001710 *
1711 * vma cannot be a COW mapping.
1712 *
1713 * As this is called only for pages that do not currently exist, we
1714 * do not need to flush old virtual caches or the TLB.
Nick Piggine0dc0d82007-02-12 00:51:36 -08001715 */
1716int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
Nick Piggin423bad62008-04-28 02:13:01 -07001717 unsigned long pfn)
Nick Piggine0dc0d82007-02-12 00:51:36 -08001718{
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001719 int ret;
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001720 pgprot_t pgprot = vma->vm_page_prot;
Nick Piggin7e675132008-04-28 02:13:00 -07001721 /*
1722 * Technically, architectures with pte_special can avoid all these
1723 * restrictions (same for remap_pfn_range). However we would like
1724 * consistency in testing and feature parity among all, so we should
1725 * try to keep these invariants in place for everybody.
1726 */
Jared Hulbertb379d792008-04-28 02:12:58 -07001727 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1728 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1729 (VM_PFNMAP|VM_MIXEDMAP));
1730 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1731 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
Nick Piggine0dc0d82007-02-12 00:51:36 -08001732
Nick Piggin423bad62008-04-28 02:13:01 -07001733 if (addr < vma->vm_start || addr >= vma->vm_end)
1734 return -EFAULT;
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001735 if (track_pfn_vma_new(vma, &pgprot, pfn, PAGE_SIZE))
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001736 return -EINVAL;
1737
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001738 ret = insert_pfn(vma, addr, pfn, pgprot);
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001739
1740 if (ret)
1741 untrack_pfn_vma(vma, pfn, PAGE_SIZE);
1742
1743 return ret;
Nick Piggine0dc0d82007-02-12 00:51:36 -08001744}
1745EXPORT_SYMBOL(vm_insert_pfn);
1746
Nick Piggin423bad62008-04-28 02:13:01 -07001747int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1748 unsigned long pfn)
1749{
1750 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1751
1752 if (addr < vma->vm_start || addr >= vma->vm_end)
1753 return -EFAULT;
1754
1755 /*
1756 * If we don't have pte special, then we have to use the pfn_valid()
1757 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1758 * refcount the page if pfn_valid is true (hence insert_page rather
Hugh Dickins62eede62009-09-21 17:03:34 -07001759 * than insert_pfn). If a zero_pfn were inserted into a VM_MIXEDMAP
1760 * without pte special, it would there be refcounted as a normal page.
Nick Piggin423bad62008-04-28 02:13:01 -07001761 */
1762 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1763 struct page *page;
1764
1765 page = pfn_to_page(pfn);
1766 return insert_page(vma, addr, page, vma->vm_page_prot);
1767 }
1768 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1769}
1770EXPORT_SYMBOL(vm_insert_mixed);
1771
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001772/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001773 * maps a range of physical memory into the requested pages. the old
1774 * mappings are removed. any references to nonexistent pages results
1775 * in null mappings (currently treated as "copy-on-access")
1776 */
1777static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1778 unsigned long addr, unsigned long end,
1779 unsigned long pfn, pgprot_t prot)
1780{
1781 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001782 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001783
Hugh Dickinsc74df322005-10-29 18:16:23 -07001784 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001785 if (!pte)
1786 return -ENOMEM;
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001787 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001788 do {
1789 BUG_ON(!pte_none(*pte));
Nick Piggin7e675132008-04-28 02:13:00 -07001790 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791 pfn++;
1792 } while (pte++, addr += PAGE_SIZE, addr != end);
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001793 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -07001794 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001795 return 0;
1796}
1797
1798static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1799 unsigned long addr, unsigned long end,
1800 unsigned long pfn, pgprot_t prot)
1801{
1802 pmd_t *pmd;
1803 unsigned long next;
1804
1805 pfn -= addr >> PAGE_SHIFT;
1806 pmd = pmd_alloc(mm, pud, addr);
1807 if (!pmd)
1808 return -ENOMEM;
1809 do {
1810 next = pmd_addr_end(addr, end);
1811 if (remap_pte_range(mm, pmd, addr, next,
1812 pfn + (addr >> PAGE_SHIFT), prot))
1813 return -ENOMEM;
1814 } while (pmd++, addr = next, addr != end);
1815 return 0;
1816}
1817
1818static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1819 unsigned long addr, unsigned long end,
1820 unsigned long pfn, pgprot_t prot)
1821{
1822 pud_t *pud;
1823 unsigned long next;
1824
1825 pfn -= addr >> PAGE_SHIFT;
1826 pud = pud_alloc(mm, pgd, addr);
1827 if (!pud)
1828 return -ENOMEM;
1829 do {
1830 next = pud_addr_end(addr, end);
1831 if (remap_pmd_range(mm, pud, addr, next,
1832 pfn + (addr >> PAGE_SHIFT), prot))
1833 return -ENOMEM;
1834 } while (pud++, addr = next, addr != end);
1835 return 0;
1836}
1837
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001838/**
1839 * remap_pfn_range - remap kernel memory to userspace
1840 * @vma: user vma to map to
1841 * @addr: target user address to start at
1842 * @pfn: physical address of kernel memory
1843 * @size: size of map area
1844 * @prot: page protection flags for this mapping
1845 *
1846 * Note: this is only safe if the mm semaphore is held when called.
1847 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001848int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1849 unsigned long pfn, unsigned long size, pgprot_t prot)
1850{
1851 pgd_t *pgd;
1852 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001853 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 struct mm_struct *mm = vma->vm_mm;
1855 int err;
1856
1857 /*
1858 * Physically remapped pages are special. Tell the
1859 * rest of the world about it:
1860 * VM_IO tells people not to look at these pages
1861 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001862 * VM_RESERVED is specified all over the place, because
1863 * in 2.4 it kept swapout's vma scan off this vma; but
1864 * in 2.6 the LRU scan won't even find its pages, so this
1865 * flag means no more than count its pages in reserved_vm,
1866 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001867 * VM_PFNMAP tells the core MM that the base pages are just
1868 * raw PFN mappings, and do not have a "struct page" associated
1869 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001870 *
1871 * There's a horrible special case to handle copy-on-write
1872 * behaviour that some programs depend on. We mark the "original"
1873 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001874 */
Pallipadi, Venkatesh4bb9c5c2009-03-12 17:45:27 -07001875 if (addr == vma->vm_start && end == vma->vm_end) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001876 vma->vm_pgoff = pfn;
Pallipadi, Venkatesh895791d2009-03-13 16:35:44 -07001877 vma->vm_flags |= VM_PFN_AT_MMAP;
Pallipadi, Venkatesh4bb9c5c2009-03-12 17:45:27 -07001878 } else if (is_cow_mapping(vma->vm_flags))
venkatesh.pallipadi@intel.com3c8bb732008-12-18 11:41:27 -08001879 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001880
Linus Torvalds6aab3412005-11-28 14:34:23 -08001881 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001882
venkatesh.pallipadi@intel.come4b866e2009-01-09 16:13:11 -08001883 err = track_pfn_vma_new(vma, &prot, pfn, PAGE_ALIGN(size));
venkatesh.pallipadi@intel.coma3670612009-01-09 16:13:09 -08001884 if (err) {
1885 /*
1886 * To indicate that track_pfn related cleanup is not
1887 * needed from higher level routine calling unmap_vmas
1888 */
1889 vma->vm_flags &= ~(VM_IO | VM_RESERVED | VM_PFNMAP);
Pallipadi, Venkatesh895791d2009-03-13 16:35:44 -07001890 vma->vm_flags &= ~VM_PFN_AT_MMAP;
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001891 return -EINVAL;
venkatesh.pallipadi@intel.coma3670612009-01-09 16:13:09 -08001892 }
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001893
Linus Torvalds1da177e2005-04-16 15:20:36 -07001894 BUG_ON(addr >= end);
1895 pfn -= addr >> PAGE_SHIFT;
1896 pgd = pgd_offset(mm, addr);
1897 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001898 do {
1899 next = pgd_addr_end(addr, end);
1900 err = remap_pud_range(mm, pgd, addr, next,
1901 pfn + (addr >> PAGE_SHIFT), prot);
1902 if (err)
1903 break;
1904 } while (pgd++, addr = next, addr != end);
venkatesh.pallipadi@intel.com2ab64032008-12-18 11:41:29 -08001905
1906 if (err)
1907 untrack_pfn_vma(vma, pfn, PAGE_ALIGN(size));
1908
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909 return err;
1910}
1911EXPORT_SYMBOL(remap_pfn_range);
1912
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001913static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1914 unsigned long addr, unsigned long end,
1915 pte_fn_t fn, void *data)
1916{
1917 pte_t *pte;
1918 int err;
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001919 pgtable_t token;
Borislav Petkov94909912007-05-06 14:49:17 -07001920 spinlock_t *uninitialized_var(ptl);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001921
1922 pte = (mm == &init_mm) ?
1923 pte_alloc_kernel(pmd, addr) :
1924 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1925 if (!pte)
1926 return -ENOMEM;
1927
1928 BUG_ON(pmd_huge(*pmd));
1929
Jeremy Fitzhardinge38e0edb2009-01-06 14:39:21 -08001930 arch_enter_lazy_mmu_mode();
1931
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001932 token = pmd_pgtable(*pmd);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001933
1934 do {
Daisuke Nishimurac36987e2009-10-26 16:50:23 -07001935 err = fn(pte++, token, addr, data);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001936 if (err)
1937 break;
Daisuke Nishimurac36987e2009-10-26 16:50:23 -07001938 } while (addr += PAGE_SIZE, addr != end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001939
Jeremy Fitzhardinge38e0edb2009-01-06 14:39:21 -08001940 arch_leave_lazy_mmu_mode();
1941
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001942 if (mm != &init_mm)
1943 pte_unmap_unlock(pte-1, ptl);
1944 return err;
1945}
1946
1947static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1948 unsigned long addr, unsigned long end,
1949 pte_fn_t fn, void *data)
1950{
1951 pmd_t *pmd;
1952 unsigned long next;
1953 int err;
1954
Andi Kleenceb86872008-07-23 21:27:50 -07001955 BUG_ON(pud_huge(*pud));
1956
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001957 pmd = pmd_alloc(mm, pud, addr);
1958 if (!pmd)
1959 return -ENOMEM;
1960 do {
1961 next = pmd_addr_end(addr, end);
1962 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1963 if (err)
1964 break;
1965 } while (pmd++, addr = next, addr != end);
1966 return err;
1967}
1968
1969static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1970 unsigned long addr, unsigned long end,
1971 pte_fn_t fn, void *data)
1972{
1973 pud_t *pud;
1974 unsigned long next;
1975 int err;
1976
1977 pud = pud_alloc(mm, pgd, addr);
1978 if (!pud)
1979 return -ENOMEM;
1980 do {
1981 next = pud_addr_end(addr, end);
1982 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1983 if (err)
1984 break;
1985 } while (pud++, addr = next, addr != end);
1986 return err;
1987}
1988
1989/*
1990 * Scan a region of virtual memory, filling in page tables as necessary
1991 * and calling a provided function on each leaf page table.
1992 */
1993int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1994 unsigned long size, pte_fn_t fn, void *data)
1995{
1996 pgd_t *pgd;
1997 unsigned long next;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001998 unsigned long start = addr, end = addr + size;
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001999 int err;
2000
2001 BUG_ON(addr >= end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002002 mmu_notifier_invalidate_range_start(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07002003 pgd = pgd_offset(mm, addr);
2004 do {
2005 next = pgd_addr_end(addr, end);
2006 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
2007 if (err)
2008 break;
2009 } while (pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07002010 mmu_notifier_invalidate_range_end(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07002011 return err;
2012}
2013EXPORT_SYMBOL_GPL(apply_to_page_range);
2014
Linus Torvalds1da177e2005-04-16 15:20:36 -07002015/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002016 * handle_pte_fault chooses page fault handler according to an entry
2017 * which was read non-atomically. Before making any commitment, on
2018 * those architectures or configurations (e.g. i386 with PAE) which
2019 * might give a mix of unmatched parts, do_swap_page and do_file_page
2020 * must check under lock before unmapping the pte and proceeding
2021 * (but do_wp_page is only called after already making such a check;
2022 * and do_anonymous_page and do_no_page can safely check later on).
2023 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002024static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002025 pte_t *page_table, pte_t orig_pte)
2026{
2027 int same = 1;
2028#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
2029 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002030 spinlock_t *ptl = pte_lockptr(mm, pmd);
2031 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002032 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002033 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002034 }
2035#endif
2036 pte_unmap(page_table);
2037 return same;
2038}
2039
2040/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002041 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
2042 * servicing faults for write access. In the normal case, do always want
2043 * pte_mkwrite. But get_user_pages can cause write faults for mappings
2044 * that do not have writing enabled, when used by access_process_vm.
2045 */
2046static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
2047{
2048 if (likely(vma->vm_flags & VM_WRITE))
2049 pte = pte_mkwrite(pte);
2050 return pte;
2051}
2052
Atsushi Nemoto9de455b2006-12-12 17:14:55 +00002053static 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 -08002054{
2055 /*
2056 * If the source page was a PFN mapping, we don't have
2057 * a "struct page" for it. We do a best-effort copy by
2058 * just copying from the original user address. If that
2059 * fails, we just zero-fill it. Live with it.
2060 */
2061 if (unlikely(!src)) {
2062 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2db2005-11-29 14:07:55 -08002063 void __user *uaddr = (void __user *)(va & PAGE_MASK);
2064
2065 /*
2066 * This really shouldn't fail, because the page is there
2067 * in the page tables. But it might just be unreadable,
2068 * in which case we just give up and fill the result with
2069 * zeroes.
2070 */
2071 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08002072 memset(kaddr, 0, PAGE_SIZE);
2073 kunmap_atomic(kaddr, KM_USER0);
Dmitriy Monakhovc4ec7b02006-10-19 23:29:08 -07002074 flush_dcache_page(dst);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002075 } else
2076 copy_user_highpage(dst, src, va, vma);
Linus Torvalds6aab3412005-11-28 14:34:23 -08002077}
2078
Linus Torvalds1da177e2005-04-16 15:20:36 -07002079/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080 * This routine handles present pages, when users try to write
2081 * to a shared page. It is done by copying the page to a new address
2082 * and decrementing the shared-page counter for the old page.
2083 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07002084 * Note that this routine assumes that the protection checks have been
2085 * done by the caller (the low-level page fault routine in most cases).
2086 * Thus we can safely just mark it writable once we've done any necessary
2087 * COW.
2088 *
2089 * We also mark the page dirty at this point even though the page will
2090 * change only once the write actually happens. This avoids a few races,
2091 * and potentially makes it more efficient.
2092 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002093 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2094 * but allow concurrent faults), with pte both mapped and locked.
2095 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002097static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
2098 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002099 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00002101 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102 pte_t entry;
Nick Piggin83c54072007-07-19 01:47:05 -07002103 int reuse = 0, ret = 0;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002104 int page_mkwrite = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002105 struct page *dirty_page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002106
Linus Torvalds6aab3412005-11-28 14:34:23 -08002107 old_page = vm_normal_page(vma, address, orig_pte);
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002108 if (!old_page) {
2109 /*
2110 * VM_MIXEDMAP !pfn_valid() case
2111 *
2112 * We should not cow pages in a shared writeable mapping.
2113 * Just mark the pages writable as we can't do any dirty
2114 * accounting on raw pfn maps.
2115 */
2116 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
2117 (VM_WRITE|VM_SHARED))
2118 goto reuse;
Linus Torvalds6aab3412005-11-28 14:34:23 -08002119 goto gotten;
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002120 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002122 /*
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002123 * Take out anonymous pages first, anonymous shared vmas are
2124 * not dirty accountable.
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002125 */
Hugh Dickins9a840892009-09-21 17:02:01 -07002126 if (PageAnon(old_page) && !PageKsm(old_page)) {
Hugh Dickinsab967d82009-01-06 14:39:33 -08002127 if (!trylock_page(old_page)) {
2128 page_cache_get(old_page);
2129 pte_unmap_unlock(page_table, ptl);
2130 lock_page(old_page);
2131 page_table = pte_offset_map_lock(mm, pmd, address,
2132 &ptl);
2133 if (!pte_same(*page_table, orig_pte)) {
2134 unlock_page(old_page);
2135 page_cache_release(old_page);
2136 goto unlock;
2137 }
2138 page_cache_release(old_page);
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002139 }
Hugh Dickins7b1fe592009-01-06 14:39:34 -08002140 reuse = reuse_swap_page(old_page);
Rik van Rielc44b6742010-03-05 13:42:09 -08002141 if (reuse)
2142 /*
2143 * The page is all ours. Move it to our anon_vma so
2144 * the rmap code will not search our parent or siblings.
2145 * Protected against the rmap code by the page lock.
2146 */
2147 page_move_anon_rmap(old_page, vma, address);
Hugh Dickinsab967d82009-01-06 14:39:33 -08002148 unlock_page(old_page);
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002149 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002150 (VM_WRITE|VM_SHARED))) {
Peter Zijlstraee6a6452006-09-25 23:31:00 -07002151 /*
2152 * Only catch write-faults on shared writable pages,
2153 * read-only shared pages can get COWed by
2154 * get_user_pages(.write=1, .force=1).
2155 */
David Howells9637a5e2006-06-23 02:03:43 -07002156 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
Nick Pigginc2ec1752009-03-31 15:23:21 -07002157 struct vm_fault vmf;
2158 int tmp;
2159
2160 vmf.virtual_address = (void __user *)(address &
2161 PAGE_MASK);
2162 vmf.pgoff = old_page->index;
2163 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
2164 vmf.page = old_page;
2165
David Howells9637a5e2006-06-23 02:03:43 -07002166 /*
2167 * Notify the address space that the page is about to
2168 * become writable so that it can prohibit this or wait
2169 * for the page to get into an appropriate state.
2170 *
2171 * We do this without the lock held, so that it can
2172 * sleep if it needs to.
2173 */
2174 page_cache_get(old_page);
2175 pte_unmap_unlock(page_table, ptl);
2176
Nick Pigginc2ec1752009-03-31 15:23:21 -07002177 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2178 if (unlikely(tmp &
2179 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2180 ret = tmp;
David Howells9637a5e2006-06-23 02:03:43 -07002181 goto unwritable_page;
Nick Pigginc2ec1752009-03-31 15:23:21 -07002182 }
Nick Pigginb827e492009-04-30 15:08:16 -07002183 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2184 lock_page(old_page);
2185 if (!old_page->mapping) {
2186 ret = 0; /* retry the fault */
2187 unlock_page(old_page);
2188 goto unwritable_page;
2189 }
2190 } else
2191 VM_BUG_ON(!PageLocked(old_page));
David Howells9637a5e2006-06-23 02:03:43 -07002192
David Howells9637a5e2006-06-23 02:03:43 -07002193 /*
2194 * Since we dropped the lock we need to revalidate
2195 * the PTE as someone else may have changed it. If
2196 * they did, we just return, as we can count on the
2197 * MMU to tell us if they didn't also make it writable.
2198 */
2199 page_table = pte_offset_map_lock(mm, pmd, address,
2200 &ptl);
Nick Pigginb827e492009-04-30 15:08:16 -07002201 if (!pte_same(*page_table, orig_pte)) {
2202 unlock_page(old_page);
2203 page_cache_release(old_page);
David Howells9637a5e2006-06-23 02:03:43 -07002204 goto unlock;
Nick Pigginb827e492009-04-30 15:08:16 -07002205 }
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002206
2207 page_mkwrite = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002208 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002209 dirty_page = old_page;
2210 get_page(dirty_page);
David Howells9637a5e2006-06-23 02:03:43 -07002211 reuse = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002212 }
2213
2214 if (reuse) {
Peter Zijlstra251b97f2008-07-04 09:59:24 -07002215reuse:
David Howells9637a5e2006-06-23 02:03:43 -07002216 flush_cache_page(vma, address, pte_pfn(orig_pte));
2217 entry = pte_mkyoung(orig_pte);
2218 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
KAMEZAWA Hiroyuki954ffcb2007-10-16 01:25:44 -07002219 if (ptep_set_access_flags(vma, address, page_table, entry,1))
Russell King4b3073e2009-12-18 16:40:18 +00002220 update_mmu_cache(vma, address, page_table);
David Howells9637a5e2006-06-23 02:03:43 -07002221 ret |= VM_FAULT_WRITE;
2222 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002223 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002224
2225 /*
2226 * Ok, we need to copy. Oh, well..
2227 */
Nick Pigginb5810032005-10-29 18:16:12 -07002228 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08002229gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002230 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231
2232 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07002233 goto oom;
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002234
Hugh Dickins62eede62009-09-21 17:03:34 -07002235 if (is_zero_pfn(pte_pfn(orig_pte))) {
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002236 new_page = alloc_zeroed_user_highpage_movable(vma, address);
2237 if (!new_page)
2238 goto oom;
2239 } else {
2240 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
2241 if (!new_page)
2242 goto oom;
2243 cow_user_page(new_page, old_page, address, vma);
2244 }
2245 __SetPageUptodate(new_page);
2246
Nick Pigginb291f002008-10-18 20:26:44 -07002247 /*
2248 * Don't let another task, with possibly unlocked vma,
2249 * keep the mlocked page.
2250 */
Carsten Otteab926612009-02-04 15:12:16 -08002251 if ((vma->vm_flags & VM_LOCKED) && old_page) {
Nick Pigginb291f002008-10-18 20:26:44 -07002252 lock_page(old_page); /* for LRU manipulation */
2253 clear_page_mlock(old_page);
2254 unlock_page(old_page);
2255 }
Hugh Dickins65500d22005-10-29 18:15:59 -07002256
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002257 if (mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002258 goto oom_free_new;
2259
Linus Torvalds1da177e2005-04-16 15:20:36 -07002260 /*
2261 * Re-check the pte - we dropped the lock
2262 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002263 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07002264 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08002265 if (old_page) {
Hugh Dickins920fc352005-11-21 21:32:17 -08002266 if (!PageAnon(old_page)) {
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002267 dec_mm_counter_fast(mm, MM_FILEPAGES);
2268 inc_mm_counter_fast(mm, MM_ANONPAGES);
Hugh Dickins920fc352005-11-21 21:32:17 -08002269 }
2270 } else
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002271 inc_mm_counter_fast(mm, MM_ANONPAGES);
Ben Collinseca35132005-11-29 11:45:26 -08002272 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07002273 entry = mk_pte(new_page, vma->vm_page_prot);
2274 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Siddha, Suresh B4ce072f2006-09-29 01:58:42 -07002275 /*
2276 * Clear the pte entry and flush it first, before updating the
2277 * pte with the new entry. This will avoid a race condition
2278 * seen in the presence of one thread doing SMC and another
2279 * thread doing COW.
2280 */
Izik Eidus828502d2009-09-21 17:01:51 -07002281 ptep_clear_flush(vma, address, page_table);
Nick Piggin9617d952006-01-06 00:11:12 -08002282 page_add_new_anon_rmap(new_page, vma, address);
Izik Eidus828502d2009-09-21 17:01:51 -07002283 /*
2284 * We call the notify macro here because, when using secondary
2285 * mmu page tables (such as kvm shadow page tables), we want the
2286 * new page to be mapped directly into the secondary page table.
2287 */
2288 set_pte_at_notify(mm, address, page_table, entry);
Russell King4b3073e2009-12-18 16:40:18 +00002289 update_mmu_cache(vma, address, page_table);
Nick Piggin945754a2008-06-23 14:30:30 +02002290 if (old_page) {
2291 /*
2292 * Only after switching the pte to the new page may
2293 * we remove the mapcount here. Otherwise another
2294 * process may come and find the rmap count decremented
2295 * before the pte is switched to the new page, and
2296 * "reuse" the old page writing into it while our pte
2297 * here still points into it and can be read by other
2298 * threads.
2299 *
2300 * The critical issue is to order this
2301 * page_remove_rmap with the ptp_clear_flush above.
2302 * Those stores are ordered by (if nothing else,)
2303 * the barrier present in the atomic_add_negative
2304 * in page_remove_rmap.
2305 *
2306 * Then the TLB flush in ptep_clear_flush ensures that
2307 * no process can access the old page before the
2308 * decremented mapcount is visible. And the old page
2309 * cannot be reused until after the decremented
2310 * mapcount is visible. So transitively, TLBs to
2311 * old page will be flushed before it can be reused.
2312 */
Hugh Dickinsedc315f2009-01-06 14:40:11 -08002313 page_remove_rmap(old_page);
Nick Piggin945754a2008-06-23 14:30:30 +02002314 }
2315
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316 /* Free the old page.. */
2317 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002318 ret |= VM_FAULT_WRITE;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002319 } else
2320 mem_cgroup_uncharge_page(new_page);
2321
Hugh Dickins920fc352005-11-21 21:32:17 -08002322 if (new_page)
2323 page_cache_release(new_page);
2324 if (old_page)
2325 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002326unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002327 pte_unmap_unlock(page_table, ptl);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002328 if (dirty_page) {
Nick Piggin79352892007-07-19 01:47:22 -07002329 /*
2330 * Yes, Virginia, this is actually required to prevent a race
2331 * with clear_page_dirty_for_io() from clearing the page dirty
2332 * bit after it clear all dirty ptes, but before a racing
2333 * do_wp_page installs a dirty pte.
2334 *
2335 * do_no_page is protected similarly.
2336 */
Nick Pigginb827e492009-04-30 15:08:16 -07002337 if (!page_mkwrite) {
2338 wait_on_page_locked(dirty_page);
2339 set_page_dirty_balance(dirty_page, page_mkwrite);
2340 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002341 put_page(dirty_page);
Nick Pigginb827e492009-04-30 15:08:16 -07002342 if (page_mkwrite) {
2343 struct address_space *mapping = dirty_page->mapping;
2344
2345 set_page_dirty(dirty_page);
2346 unlock_page(dirty_page);
2347 page_cache_release(dirty_page);
2348 if (mapping) {
2349 /*
2350 * Some device drivers do not set page.mapping
2351 * but still dirty their pages
2352 */
2353 balance_dirty_pages_ratelimited(mapping);
2354 }
2355 }
2356
2357 /* file_update_time outside page_lock */
2358 if (vma->vm_file)
2359 file_update_time(vma->vm_file);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002360 }
Nick Pigginf33ea7f2005-08-03 20:24:01 +10002361 return ret;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002362oom_free_new:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002363 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002364oom:
Nick Pigginb827e492009-04-30 15:08:16 -07002365 if (old_page) {
2366 if (page_mkwrite) {
2367 unlock_page(old_page);
2368 page_cache_release(old_page);
2369 }
Hugh Dickins920fc352005-11-21 21:32:17 -08002370 page_cache_release(old_page);
Nick Pigginb827e492009-04-30 15:08:16 -07002371 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002372 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07002373
2374unwritable_page:
2375 page_cache_release(old_page);
Nick Pigginc2ec1752009-03-31 15:23:21 -07002376 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002377}
2378
2379/*
2380 * Helper functions for unmap_mapping_range().
2381 *
2382 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
2383 *
2384 * We have to restart searching the prio_tree whenever we drop the lock,
2385 * since the iterator is only valid while the lock is held, and anyway
2386 * a later vma might be split and reinserted earlier while lock dropped.
2387 *
2388 * The list of nonlinear vmas could be handled more efficiently, using
2389 * a placeholder, but handle it in the same way until a need is shown.
2390 * It is important to search the prio_tree before nonlinear list: a vma
2391 * may become nonlinear and be shifted from prio_tree to nonlinear list
2392 * while the lock is dropped; but never shifted from list to prio_tree.
2393 *
2394 * In order to make forward progress despite restarting the search,
2395 * vm_truncate_count is used to mark a vma as now dealt with, so we can
2396 * quickly skip it next time around. Since the prio_tree search only
2397 * shows us those vmas affected by unmapping the range in question, we
2398 * can't efficiently keep all vmas in step with mapping->truncate_count:
2399 * so instead reset them all whenever it wraps back to 0 (then go to 1).
2400 * mapping->truncate_count and vma->vm_truncate_count are protected by
2401 * i_mmap_lock.
2402 *
2403 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07002404 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002405 * and restart from that address when we reach that vma again. It might
2406 * have been split or merged, shrunk or extended, but never shifted: so
2407 * restart_addr remains valid so long as it remains in the vma's range.
2408 * unmap_mapping_range forces truncate_count to leap over page-aligned
2409 * values so we can save vma's restart_addr in its truncate_count field.
2410 */
2411#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
2412
2413static void reset_vma_truncate_counts(struct address_space *mapping)
2414{
2415 struct vm_area_struct *vma;
2416 struct prio_tree_iter iter;
2417
2418 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2419 vma->vm_truncate_count = 0;
2420 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2421 vma->vm_truncate_count = 0;
2422}
2423
2424static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2425 unsigned long start_addr, unsigned long end_addr,
2426 struct zap_details *details)
2427{
2428 unsigned long restart_addr;
2429 int need_break;
2430
Nick Piggind00806b2007-07-19 01:46:57 -07002431 /*
2432 * files that support invalidating or truncating portions of the
Nick Piggind0217ac2007-07-19 01:47:03 -07002433 * file from under mmaped areas must have their ->fault function
Nick Piggin83c54072007-07-19 01:47:05 -07002434 * return a locked page (and set VM_FAULT_LOCKED in the return).
2435 * This provides synchronisation against concurrent unmapping here.
Nick Piggind00806b2007-07-19 01:46:57 -07002436 */
Nick Piggind00806b2007-07-19 01:46:57 -07002437
Linus Torvalds1da177e2005-04-16 15:20:36 -07002438again:
2439 restart_addr = vma->vm_truncate_count;
2440 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2441 start_addr = restart_addr;
2442 if (start_addr >= end_addr) {
2443 /* Top of vma has been split off since last time */
2444 vma->vm_truncate_count = details->truncate_count;
2445 return 0;
2446 }
2447 }
2448
Hugh Dickinsee39b372005-04-19 13:29:15 -07002449 restart_addr = zap_page_range(vma, start_addr,
2450 end_addr - start_addr, details);
Nick Piggin95c354f2008-01-30 13:31:20 +01002451 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002452
Hugh Dickinsee39b372005-04-19 13:29:15 -07002453 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002454 /* We have now completed this vma: mark it so */
2455 vma->vm_truncate_count = details->truncate_count;
2456 if (!need_break)
2457 return 0;
2458 } else {
2459 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07002460 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002461 if (!need_break)
2462 goto again;
2463 }
2464
2465 spin_unlock(details->i_mmap_lock);
2466 cond_resched();
2467 spin_lock(details->i_mmap_lock);
2468 return -EINTR;
2469}
2470
2471static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2472 struct zap_details *details)
2473{
2474 struct vm_area_struct *vma;
2475 struct prio_tree_iter iter;
2476 pgoff_t vba, vea, zba, zea;
2477
2478restart:
2479 vma_prio_tree_foreach(vma, &iter, root,
2480 details->first_index, details->last_index) {
2481 /* Skip quickly over those we have already dealt with */
2482 if (vma->vm_truncate_count == details->truncate_count)
2483 continue;
2484
2485 vba = vma->vm_pgoff;
2486 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2487 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2488 zba = details->first_index;
2489 if (zba < vba)
2490 zba = vba;
2491 zea = details->last_index;
2492 if (zea > vea)
2493 zea = vea;
2494
2495 if (unmap_mapping_range_vma(vma,
2496 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2497 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2498 details) < 0)
2499 goto restart;
2500 }
2501}
2502
2503static inline void unmap_mapping_range_list(struct list_head *head,
2504 struct zap_details *details)
2505{
2506 struct vm_area_struct *vma;
2507
2508 /*
2509 * In nonlinear VMAs there is no correspondence between virtual address
2510 * offset and file offset. So we must perform an exhaustive search
2511 * across *all* the pages in each nonlinear VMA, not just the pages
2512 * whose virtual address lies outside the file truncation point.
2513 */
2514restart:
2515 list_for_each_entry(vma, head, shared.vm_set.list) {
2516 /* Skip quickly over those we have already dealt with */
2517 if (vma->vm_truncate_count == details->truncate_count)
2518 continue;
2519 details->nonlinear_vma = vma;
2520 if (unmap_mapping_range_vma(vma, vma->vm_start,
2521 vma->vm_end, details) < 0)
2522 goto restart;
2523 }
2524}
2525
2526/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08002527 * 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 -07002528 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002529 * @holebegin: byte in first page to unmap, relative to the start of
2530 * the underlying file. This will be rounded down to a PAGE_SIZE
npiggin@suse.de25d9e2d2009-08-21 02:35:05 +10002531 * boundary. Note that this is different from truncate_pagecache(), which
Linus Torvalds1da177e2005-04-16 15:20:36 -07002532 * must keep the partial page. In contrast, we must get rid of
2533 * partial pages.
2534 * @holelen: size of prospective hole in bytes. This will be rounded
2535 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2536 * end of the file.
2537 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2538 * but 0 when invalidating pagecache, don't throw away private data.
2539 */
2540void unmap_mapping_range(struct address_space *mapping,
2541 loff_t const holebegin, loff_t const holelen, int even_cows)
2542{
2543 struct zap_details details;
2544 pgoff_t hba = holebegin >> PAGE_SHIFT;
2545 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2546
2547 /* Check for overflow. */
2548 if (sizeof(holelen) > sizeof(hlen)) {
2549 long long holeend =
2550 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2551 if (holeend & ~(long long)ULONG_MAX)
2552 hlen = ULONG_MAX - hba + 1;
2553 }
2554
2555 details.check_mapping = even_cows? NULL: mapping;
2556 details.nonlinear_vma = NULL;
2557 details.first_index = hba;
2558 details.last_index = hba + hlen - 1;
2559 if (details.last_index < details.first_index)
2560 details.last_index = ULONG_MAX;
2561 details.i_mmap_lock = &mapping->i_mmap_lock;
2562
2563 spin_lock(&mapping->i_mmap_lock);
2564
Nick Piggind00806b2007-07-19 01:46:57 -07002565 /* Protect against endless unmapping loops */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002566 mapping->truncate_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002567 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2568 if (mapping->truncate_count == 0)
2569 reset_vma_truncate_counts(mapping);
2570 mapping->truncate_count++;
2571 }
2572 details.truncate_count = mapping->truncate_count;
2573
2574 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2575 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2576 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2577 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2578 spin_unlock(&mapping->i_mmap_lock);
2579}
2580EXPORT_SYMBOL(unmap_mapping_range);
2581
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002582int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2583{
2584 struct address_space *mapping = inode->i_mapping;
2585
2586 /*
2587 * If the underlying filesystem is not going to provide
2588 * a way to truncate a range of blocks (punch a hole) -
2589 * we should return failure right now.
2590 */
Al Viroacfa4382008-12-04 10:06:33 -05002591 if (!inode->i_op->truncate_range)
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002592 return -ENOSYS;
2593
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002594 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002595 down_write(&inode->i_alloc_sem);
2596 unmap_mapping_range(mapping, offset, (end - offset), 1);
2597 truncate_inode_pages_range(mapping, offset, end);
Nick Piggind00806b2007-07-19 01:46:57 -07002598 unmap_mapping_range(mapping, offset, (end - offset), 1);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002599 inode->i_op->truncate_range(inode, offset, end);
2600 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002601 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002602
2603 return 0;
2604}
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002605
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002607 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2608 * but allow concurrent faults), and pte mapped but not yet locked.
2609 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002610 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002611static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2612 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002613 unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002614{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002615 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002616 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07002617 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002618 pte_t pte;
KAMEZAWA Hiroyuki7a81b882009-01-07 18:07:48 -08002619 struct mem_cgroup *ptr = NULL;
Nick Piggin83c54072007-07-19 01:47:05 -07002620 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002621
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002622 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002623 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07002624
2625 entry = pte_to_swp_entry(orig_pte);
Andi Kleend1737fd2009-09-16 11:50:06 +02002626 if (unlikely(non_swap_entry(entry))) {
2627 if (is_migration_entry(entry)) {
2628 migration_entry_wait(mm, pmd, address);
2629 } else if (is_hwpoison_entry(entry)) {
2630 ret = VM_FAULT_HWPOISON;
2631 } else {
2632 print_bad_pte(vma, address, orig_pte, NULL);
Hugh Dickinsd99be1a2009-12-14 17:59:04 -08002633 ret = VM_FAULT_SIGBUS;
Andi Kleend1737fd2009-09-16 11:50:06 +02002634 }
Christoph Lameter06972122006-06-23 02:03:35 -07002635 goto out;
2636 }
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002637 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002638 page = lookup_swap_cache(entry);
2639 if (!page) {
Hugh Dickinsa5c9b692009-06-23 12:36:58 -07002640 grab_swap_token(mm); /* Contend for token _before_ read-in */
Hugh Dickins02098fe2008-02-04 22:28:42 -08002641 page = swapin_readahead(entry,
2642 GFP_HIGHUSER_MOVABLE, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002643 if (!page) {
2644 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002645 * Back out if somebody else faulted in this pte
2646 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002648 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002649 if (likely(pte_same(*page_table, orig_pte)))
2650 ret = VM_FAULT_OOM;
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002651 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Hugh Dickins65500d22005-10-29 18:15:59 -07002652 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002653 }
2654
2655 /* Had to read the page from swap area: Major fault */
2656 ret = VM_FAULT_MAJOR;
Christoph Lameterf8891e52006-06-30 01:55:45 -07002657 count_vm_event(PGMAJFAULT);
Andi Kleend1737fd2009-09-16 11:50:06 +02002658 } else if (PageHWPoison(page)) {
Wu Fengguang71f72522009-12-16 12:19:58 +01002659 /*
2660 * hwpoisoned dirty swapcache pages are kept for killing
2661 * owner processes (which may be unknown at hwpoison time)
2662 */
Andi Kleend1737fd2009-09-16 11:50:06 +02002663 ret = VM_FAULT_HWPOISON;
2664 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Andi Kleen4779cb32009-10-14 01:51:41 +02002665 goto out_release;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002666 }
2667
Linus Torvalds1da177e2005-04-16 15:20:36 -07002668 lock_page(page);
Balbir Singh20a10222007-11-14 17:00:33 -08002669 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002670
Hugh Dickins5ad64682009-12-14 17:59:24 -08002671 page = ksm_might_need_to_copy(page, vma, address);
2672 if (!page) {
2673 ret = VM_FAULT_OOM;
2674 goto out;
2675 }
2676
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002677 if (mem_cgroup_try_charge_swapin(mm, page, GFP_KERNEL, &ptr)) {
KAMEZAWA Hiroyuki073e5872008-10-18 20:28:08 -07002678 ret = VM_FAULT_OOM;
Johannes Weinerbc43f752009-04-30 15:08:08 -07002679 goto out_page;
KAMEZAWA Hiroyuki073e5872008-10-18 20:28:08 -07002680 }
2681
Linus Torvalds1da177e2005-04-16 15:20:36 -07002682 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002683 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002684 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002685 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07002686 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07002687 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002688
2689 if (unlikely(!PageUptodate(page))) {
2690 ret = VM_FAULT_SIGBUS;
2691 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002692 }
2693
KAMEZAWA Hiroyuki8c7c6e32009-01-07 18:08:00 -08002694 /*
2695 * The page isn't present yet, go ahead with the fault.
2696 *
2697 * Be careful about the sequence of operations here.
2698 * To get its accounting right, reuse_swap_page() must be called
2699 * while the page is counted on swap but not yet in mapcount i.e.
2700 * before page_add_anon_rmap() and swap_free(); try_to_free_swap()
2701 * must be called after the swap_free(), or it will never succeed.
KAMEZAWA Hiroyuki03f3c432009-01-07 18:08:31 -08002702 * Because delete_from_swap_page() may be called by reuse_swap_page(),
2703 * mem_cgroup_commit_charge_swapin() may not be able to find swp_entry
2704 * in page->private. In this case, a record in swap_cgroup is silently
2705 * discarded at swap_free().
KAMEZAWA Hiroyuki8c7c6e32009-01-07 18:08:00 -08002706 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002707
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002708 inc_mm_counter_fast(mm, MM_ANONPAGES);
KAMEZAWA Hiroyukib084d432010-03-05 13:41:42 -08002709 dec_mm_counter_fast(mm, MM_SWAPENTS);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002710 pte = mk_pte(page, vma->vm_page_prot);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002711 if ((flags & FAULT_FLAG_WRITE) && reuse_swap_page(page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002712 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002713 flags &= ~FAULT_FLAG_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002714 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002715 flush_icache_page(vma, page);
2716 set_pte_at(mm, address, page_table, pte);
2717 page_add_anon_rmap(page, vma, address);
KAMEZAWA Hiroyuki03f3c432009-01-07 18:08:31 -08002718 /* It's better to call commit-charge after rmap is established */
2719 mem_cgroup_commit_charge_swapin(page, ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002720
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002721 swap_free(entry);
Nick Pigginb291f002008-10-18 20:26:44 -07002722 if (vm_swap_full() || (vma->vm_flags & VM_LOCKED) || PageMlocked(page))
Hugh Dickinsa2c43ee2009-01-06 14:39:36 -08002723 try_to_free_swap(page);
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002724 unlock_page(page);
2725
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002726 if (flags & FAULT_FLAG_WRITE) {
Hugh Dickins61469f12008-03-04 14:29:04 -08002727 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2728 if (ret & VM_FAULT_ERROR)
2729 ret &= VM_FAULT_ERROR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002730 goto out;
2731 }
2732
2733 /* No need to invalidate - it was non-present before */
Russell King4b3073e2009-12-18 16:40:18 +00002734 update_mmu_cache(vma, address, page_table);
Hugh Dickins65500d22005-10-29 18:15:59 -07002735unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002736 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002737out:
2738 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002739out_nomap:
KAMEZAWA Hiroyuki7a81b882009-01-07 18:07:48 -08002740 mem_cgroup_cancel_charge_swapin(ptr);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002741 pte_unmap_unlock(page_table, ptl);
Johannes Weinerbc43f752009-04-30 15:08:08 -07002742out_page:
Kirill Korotaevb8107482005-05-16 21:53:50 -07002743 unlock_page(page);
Andi Kleen4779cb32009-10-14 01:51:41 +02002744out_release:
Kirill Korotaevb8107482005-05-16 21:53:50 -07002745 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002746 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002747}
2748
2749/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002750 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2751 * but allow concurrent faults), and pte mapped but not yet locked.
2752 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002753 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002754static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2755 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002756 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002757{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002758 struct page *page;
2759 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002760 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002761
Hugh Dickins62eede62009-09-21 17:03:34 -07002762 if (!(flags & FAULT_FLAG_WRITE)) {
2763 entry = pte_mkspecial(pfn_pte(my_zero_pfn(address),
2764 vma->vm_page_prot));
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002765 ptl = pte_lockptr(mm, pmd);
2766 spin_lock(ptl);
2767 if (!pte_none(*page_table))
2768 goto unlock;
2769 goto setpte;
2770 }
2771
Nick Piggin557ed1f2007-10-16 01:24:40 -07002772 /* Allocate our own private page. */
2773 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002774
Nick Piggin557ed1f2007-10-16 01:24:40 -07002775 if (unlikely(anon_vma_prepare(vma)))
2776 goto oom;
2777 page = alloc_zeroed_user_highpage_movable(vma, address);
2778 if (!page)
2779 goto oom;
Nick Piggin0ed361d2008-02-04 22:29:34 -08002780 __SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002781
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002782 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002783 goto oom_free_page;
2784
Nick Piggin557ed1f2007-10-16 01:24:40 -07002785 entry = mk_pte(page, vma->vm_page_prot);
Hugh Dickins1ac0cb52009-09-21 17:03:29 -07002786 if (vma->vm_flags & VM_WRITE)
2787 entry = pte_mkwrite(pte_mkdirty(entry));
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002788
Nick Piggin557ed1f2007-10-16 01:24:40 -07002789 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Andrea Arcangeli1c2fb7a2009-09-21 17:02:22 -07002790 if (!pte_none(*page_table))
Nick Piggin557ed1f2007-10-16 01:24:40 -07002791 goto release;
Hugh Dickins9ba69292009-09-21 17:02:20 -07002792
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002793 inc_mm_counter_fast(mm, MM_ANONPAGES);
Nick Piggin557ed1f2007-10-16 01:24:40 -07002794 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsa13ea5b2009-09-21 17:03:30 -07002795setpte:
Hugh Dickins65500d22005-10-29 18:15:59 -07002796 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002797
2798 /* No need to invalidate - it was non-present before */
Russell King4b3073e2009-12-18 16:40:18 +00002799 update_mmu_cache(vma, address, page_table);
Hugh Dickins65500d22005-10-29 18:15:59 -07002800unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002801 pte_unmap_unlock(page_table, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002802 return 0;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002803release:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002804 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002805 page_cache_release(page);
2806 goto unlock;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002807oom_free_page:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002808 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002809oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002810 return VM_FAULT_OOM;
2811}
2812
2813/*
Nick Piggin54cb8822007-07-19 01:46:59 -07002814 * __do_fault() tries to create a new page mapping. It aggressively
Linus Torvalds1da177e2005-04-16 15:20:36 -07002815 * tries to share with existing pages, but makes a separate copy if
Nick Piggin54cb8822007-07-19 01:46:59 -07002816 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2817 * the next page fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002818 *
2819 * As this is called only for pages that do not currently exist, we
2820 * do not need to flush old virtual caches or the TLB.
2821 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002822 * We enter with non-exclusive mmap_sem (to exclude vma changes,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002823 * but allow concurrent faults), and pte neither mapped nor locked.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002824 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002825 */
Nick Piggin54cb8822007-07-19 01:46:59 -07002826static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002827 unsigned long address, pmd_t *pmd,
Nick Piggin54cb8822007-07-19 01:46:59 -07002828 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002829{
Hugh Dickins16abfa02007-10-04 16:56:06 +01002830 pte_t *page_table;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002831 spinlock_t *ptl;
Nick Piggind0217ac2007-07-19 01:47:03 -07002832 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002833 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002834 int anon = 0;
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002835 int charged = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002836 struct page *dirty_page = NULL;
Nick Piggind0217ac2007-07-19 01:47:03 -07002837 struct vm_fault vmf;
2838 int ret;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002839 int page_mkwrite = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07002840
Nick Piggind0217ac2007-07-19 01:47:03 -07002841 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2842 vmf.pgoff = pgoff;
2843 vmf.flags = flags;
2844 vmf.page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002845
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002846 ret = vma->vm_ops->fault(vma, &vmf);
2847 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2848 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002849
Andi Kleena3b947e2009-09-16 11:50:08 +02002850 if (unlikely(PageHWPoison(vmf.page))) {
2851 if (ret & VM_FAULT_LOCKED)
2852 unlock_page(vmf.page);
2853 return VM_FAULT_HWPOISON;
2854 }
2855
Nick Piggind00806b2007-07-19 01:46:57 -07002856 /*
Nick Piggind0217ac2007-07-19 01:47:03 -07002857 * For consistency in subsequent calls, make the faulted page always
Nick Piggind00806b2007-07-19 01:46:57 -07002858 * locked.
2859 */
Nick Piggin83c54072007-07-19 01:47:05 -07002860 if (unlikely(!(ret & VM_FAULT_LOCKED)))
Nick Piggind0217ac2007-07-19 01:47:03 -07002861 lock_page(vmf.page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002862 else
Nick Piggind0217ac2007-07-19 01:47:03 -07002863 VM_BUG_ON(!PageLocked(vmf.page));
Nick Piggind00806b2007-07-19 01:46:57 -07002864
Linus Torvalds1da177e2005-04-16 15:20:36 -07002865 /*
2866 * Should we do an early C-O-W break?
2867 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002868 page = vmf.page;
Nick Piggin54cb8822007-07-19 01:46:59 -07002869 if (flags & FAULT_FLAG_WRITE) {
David Howells9637a5e2006-06-23 02:03:43 -07002870 if (!(vma->vm_flags & VM_SHARED)) {
Nick Piggin54cb8822007-07-19 01:46:59 -07002871 anon = 1;
Nick Piggind00806b2007-07-19 01:46:57 -07002872 if (unlikely(anon_vma_prepare(vma))) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002873 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002874 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002875 }
Nick Piggin83c54072007-07-19 01:47:05 -07002876 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2877 vma, address);
Nick Piggind00806b2007-07-19 01:46:57 -07002878 if (!page) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002879 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002880 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002881 }
KAMEZAWA Hiroyuki2c26fdd2009-01-07 18:08:10 -08002882 if (mem_cgroup_newpage_charge(page, mm, GFP_KERNEL)) {
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002883 ret = VM_FAULT_OOM;
2884 page_cache_release(page);
2885 goto out;
2886 }
2887 charged = 1;
Nick Pigginb291f002008-10-18 20:26:44 -07002888 /*
2889 * Don't let another task, with possibly unlocked vma,
2890 * keep the mlocked page.
2891 */
2892 if (vma->vm_flags & VM_LOCKED)
2893 clear_page_mlock(vmf.page);
Nick Piggind0217ac2007-07-19 01:47:03 -07002894 copy_user_highpage(page, vmf.page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002895 __SetPageUptodate(page);
David Howells9637a5e2006-06-23 02:03:43 -07002896 } else {
Nick Piggin54cb8822007-07-19 01:46:59 -07002897 /*
2898 * If the page will be shareable, see if the backing
David Howells9637a5e2006-06-23 02:03:43 -07002899 * address space wants to know that the page is about
Nick Piggin54cb8822007-07-19 01:46:59 -07002900 * to become writable
2901 */
Mark Fasheh69676142007-07-19 01:47:00 -07002902 if (vma->vm_ops->page_mkwrite) {
Nick Pigginc2ec1752009-03-31 15:23:21 -07002903 int tmp;
2904
Mark Fasheh69676142007-07-19 01:47:00 -07002905 unlock_page(page);
Nick Pigginb827e492009-04-30 15:08:16 -07002906 vmf.flags = FAULT_FLAG_WRITE|FAULT_FLAG_MKWRITE;
Nick Pigginc2ec1752009-03-31 15:23:21 -07002907 tmp = vma->vm_ops->page_mkwrite(vma, &vmf);
2908 if (unlikely(tmp &
2909 (VM_FAULT_ERROR | VM_FAULT_NOPAGE))) {
2910 ret = tmp;
Nick Pigginb827e492009-04-30 15:08:16 -07002911 goto unwritable_page;
Mark Fasheh69676142007-07-19 01:47:00 -07002912 }
Nick Pigginb827e492009-04-30 15:08:16 -07002913 if (unlikely(!(tmp & VM_FAULT_LOCKED))) {
2914 lock_page(page);
2915 if (!page->mapping) {
2916 ret = 0; /* retry the fault */
2917 unlock_page(page);
2918 goto unwritable_page;
2919 }
2920 } else
2921 VM_BUG_ON(!PageLocked(page));
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002922 page_mkwrite = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002923 }
2924 }
Nick Piggin54cb8822007-07-19 01:46:59 -07002925
Linus Torvalds1da177e2005-04-16 15:20:36 -07002926 }
2927
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002928 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002929
2930 /*
2931 * This silly early PAGE_DIRTY setting removes a race
2932 * due to the bad i386 page protection. But it's valid
2933 * for other architectures too.
2934 *
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07002935 * Note that if FAULT_FLAG_WRITE is set, we either now have
Linus Torvalds1da177e2005-04-16 15:20:36 -07002936 * an exclusive copy of the page, or this is a shared mapping,
2937 * so we can make it writable and dirty to avoid having to
2938 * handle that later.
2939 */
2940 /* Only go through if we didn't race with anybody else... */
Andrea Arcangeli1c2fb7a2009-09-21 17:02:22 -07002941 if (likely(pte_same(*page_table, orig_pte))) {
Nick Piggind00806b2007-07-19 01:46:57 -07002942 flush_icache_page(vma, page);
2943 entry = mk_pte(page, vma->vm_page_prot);
Nick Piggin54cb8822007-07-19 01:46:59 -07002944 if (flags & FAULT_FLAG_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002945 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002946 if (anon) {
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002947 inc_mm_counter_fast(mm, MM_ANONPAGES);
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002948 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002949 } else {
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08002950 inc_mm_counter_fast(mm, MM_FILEPAGES);
Nick Piggind00806b2007-07-19 01:46:57 -07002951 page_add_file_rmap(page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002952 if (flags & FAULT_FLAG_WRITE) {
Nick Piggind00806b2007-07-19 01:46:57 -07002953 dirty_page = page;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002954 get_page(dirty_page);
2955 }
Hugh Dickins42946212005-10-29 18:16:05 -07002956 }
Lee Schermerhorn64d65192008-10-18 20:26:52 -07002957 set_pte_at(mm, address, page_table, entry);
Nick Piggind00806b2007-07-19 01:46:57 -07002958
2959 /* no need to invalidate: a not-present page won't be cached */
Russell King4b3073e2009-12-18 16:40:18 +00002960 update_mmu_cache(vma, address, page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002961 } else {
KAMEZAWA Hiroyuki5b4e6552008-10-18 20:28:10 -07002962 if (charged)
2963 mem_cgroup_uncharge_page(page);
Nick Piggind00806b2007-07-19 01:46:57 -07002964 if (anon)
2965 page_cache_release(page);
2966 else
Nick Piggin54cb8822007-07-19 01:46:59 -07002967 anon = 1; /* no anon but release faulted_page */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002968 }
2969
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002970 pte_unmap_unlock(page_table, ptl);
Nick Piggind00806b2007-07-19 01:46:57 -07002971
2972out:
Nick Pigginb827e492009-04-30 15:08:16 -07002973 if (dirty_page) {
2974 struct address_space *mapping = page->mapping;
2975
2976 if (set_page_dirty(dirty_page))
2977 page_mkwrite = 1;
2978 unlock_page(dirty_page);
2979 put_page(dirty_page);
2980 if (page_mkwrite && mapping) {
2981 /*
2982 * Some device drivers do not set page.mapping but still
2983 * dirty their pages
2984 */
2985 balance_dirty_pages_ratelimited(mapping);
2986 }
2987
2988 /* file_update_time outside page_lock */
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03002989 if (vma->vm_file)
2990 file_update_time(vma->vm_file);
Nick Pigginb827e492009-04-30 15:08:16 -07002991 } else {
2992 unlock_page(vmf.page);
2993 if (anon)
2994 page_cache_release(vmf.page);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002995 }
Nick Piggind00806b2007-07-19 01:46:57 -07002996
Nick Piggin83c54072007-07-19 01:47:05 -07002997 return ret;
Nick Pigginb827e492009-04-30 15:08:16 -07002998
2999unwritable_page:
3000 page_cache_release(page);
3001 return ret;
Nick Piggin54cb8822007-07-19 01:46:59 -07003002}
Nick Piggind00806b2007-07-19 01:46:57 -07003003
Nick Piggin54cb8822007-07-19 01:46:59 -07003004static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3005 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003006 unsigned int flags, pte_t orig_pte)
Nick Piggin54cb8822007-07-19 01:46:59 -07003007{
3008 pgoff_t pgoff = (((address & PAGE_MASK)
Dean Nelson0da7e012007-10-16 01:24:45 -07003009 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
Nick Piggin54cb8822007-07-19 01:46:59 -07003010
Hugh Dickins16abfa02007-10-04 16:56:06 +01003011 pte_unmap(page_table);
3012 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Nick Piggin54cb8822007-07-19 01:46:59 -07003013}
3014
Jes Sorensenf4b81802006-09-27 01:50:10 -07003015/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003016 * Fault of a previously existing named mapping. Repopulate the pte
3017 * from the encoded file_pte if possible. This enables swappable
3018 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003019 *
3020 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3021 * but allow concurrent faults), and pte mapped but not yet locked.
3022 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003023 */
Nick Piggind0217ac2007-07-19 01:47:03 -07003024static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins65500d22005-10-29 18:15:59 -07003025 unsigned long address, pte_t *page_table, pmd_t *pmd,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003026 unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003027{
Hugh Dickins65500d22005-10-29 18:15:59 -07003028 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003029
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003030 flags |= FAULT_FLAG_NONLINEAR;
3031
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07003032 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Nick Piggin83c54072007-07-19 01:47:05 -07003033 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003034
Hugh Dickins2509ef22009-01-06 14:40:10 -08003035 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
Hugh Dickins65500d22005-10-29 18:15:59 -07003036 /*
3037 * Page table corrupted: show pte and kill process.
3038 */
Hugh Dickins3dc14742009-01-06 14:40:08 -08003039 print_bad_pte(vma, address, orig_pte, NULL);
Hugh Dickinsd99be1a2009-12-14 17:59:04 -08003040 return VM_FAULT_SIGBUS;
Hugh Dickins65500d22005-10-29 18:15:59 -07003041 }
Hugh Dickins65500d22005-10-29 18:15:59 -07003042
3043 pgoff = pte_to_pgoff(orig_pte);
Hugh Dickins16abfa02007-10-04 16:56:06 +01003044 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003045}
3046
3047/*
3048 * These routines also need to handle stuff like marking pages dirty
3049 * and/or accessed for architectures that don't do it in hardware (most
3050 * RISC architectures). The early dirtying is also good on the i386.
3051 *
3052 * There is also a hook called "update_mmu_cache()" that architectures
3053 * with external mmu caches can use to update those (ie the Sparc or
3054 * PowerPC hashed page tables that act as extended TLBs).
3055 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07003056 * We enter with non-exclusive mmap_sem (to exclude vma changes,
3057 * but allow concurrent faults), and pte mapped but not yet locked.
3058 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003059 */
3060static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07003061 struct vm_area_struct *vma, unsigned long address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003062 pte_t *pte, pmd_t *pmd, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003063{
3064 pte_t entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003065 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003066
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07003067 entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003068 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07003069 if (pte_none(entry)) {
Jes Sorensenf4b81802006-09-27 01:50:10 -07003070 if (vma->vm_ops) {
Nick Piggin3c18ddd2008-04-28 02:12:10 -07003071 if (likely(vma->vm_ops->fault))
Nick Piggin54cb8822007-07-19 01:46:59 -07003072 return do_linear_fault(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003073 pte, pmd, flags, entry);
Jes Sorensenf4b81802006-09-27 01:50:10 -07003074 }
3075 return do_anonymous_page(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003076 pte, pmd, flags);
Hugh Dickins65500d22005-10-29 18:15:59 -07003077 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003078 if (pte_file(entry))
Nick Piggind0217ac2007-07-19 01:47:03 -07003079 return do_nonlinear_fault(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003080 pte, pmd, flags, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07003081 return do_swap_page(mm, vma, address,
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003082 pte, pmd, flags, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003083 }
3084
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07003085 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003086 spin_lock(ptl);
3087 if (unlikely(!pte_same(*pte, entry)))
3088 goto unlock;
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003089 if (flags & FAULT_FLAG_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003090 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003091 return do_wp_page(mm, vma, address,
3092 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003093 entry = pte_mkdirty(entry);
3094 }
3095 entry = pte_mkyoung(entry);
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003096 if (ptep_set_access_flags(vma, address, pte, entry, flags & FAULT_FLAG_WRITE)) {
Russell King4b3073e2009-12-18 16:40:18 +00003097 update_mmu_cache(vma, address, pte);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07003098 } else {
3099 /*
3100 * This is needed only for protection faults but the arch code
3101 * is not yet telling us if this is a protection fault or not.
3102 * This still avoids useless tlb flushes for .text page faults
3103 * with threads.
3104 */
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003105 if (flags & FAULT_FLAG_WRITE)
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07003106 flush_tlb_page(vma, address);
3107 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07003108unlock:
3109 pte_unmap_unlock(pte, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07003110 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003111}
3112
3113/*
3114 * By the time we get here, we already hold the mm semaphore
3115 */
Nick Piggin83c54072007-07-19 01:47:05 -07003116int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvaldsd06063c2009-04-10 09:01:23 -07003117 unsigned long address, unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003118{
3119 pgd_t *pgd;
3120 pud_t *pud;
3121 pmd_t *pmd;
3122 pte_t *pte;
3123
3124 __set_current_state(TASK_RUNNING);
3125
Christoph Lameterf8891e52006-06-30 01:55:45 -07003126 count_vm_event(PGFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003127
KAMEZAWA Hiroyuki34e55232010-03-05 13:41:40 -08003128 /* do counter updates before entering really critical section. */
3129 check_sync_rss_stat(current);
3130
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01003131 if (unlikely(is_vm_hugetlb_page(vma)))
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003132 return hugetlb_fault(mm, vma, address, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003133
Linus Torvalds1da177e2005-04-16 15:20:36 -07003134 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003135 pud = pud_alloc(mm, pgd, address);
3136 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003137 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003138 pmd = pmd_alloc(mm, pud, address);
3139 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003140 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003141 pte = pte_alloc_map(mm, pmd, address);
3142 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07003143 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003144
Linus Torvalds30c9f3a2009-04-10 08:43:11 -07003145 return handle_pte_fault(mm, vma, address, pte, pmd, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003146}
3147
3148#ifndef __PAGETABLE_PUD_FOLDED
3149/*
3150 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07003151 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003152 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07003153int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003154{
Hugh Dickinsc74df322005-10-29 18:16:23 -07003155 pud_t *new = pud_alloc_one(mm, address);
3156 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07003157 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003158
Nick Piggin362a61a2008-05-14 06:37:36 +02003159 smp_wmb(); /* See comment in __pte_alloc */
3160
Hugh Dickins872fec12005-10-29 18:16:21 -07003161 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003162 if (pgd_present(*pgd)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003163 pud_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003164 else
3165 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07003166 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003167 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003168}
3169#endif /* __PAGETABLE_PUD_FOLDED */
3170
3171#ifndef __PAGETABLE_PMD_FOLDED
3172/*
3173 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07003174 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003175 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07003176int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003177{
Hugh Dickinsc74df322005-10-29 18:16:23 -07003178 pmd_t *new = pmd_alloc_one(mm, address);
3179 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07003180 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003181
Nick Piggin362a61a2008-05-14 06:37:36 +02003182 smp_wmb(); /* See comment in __pte_alloc */
3183
Hugh Dickins872fec12005-10-29 18:16:21 -07003184 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003185#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07003186 if (pud_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003187 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003188 else
3189 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003190#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07003191 if (pgd_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08003192 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003193 else
3194 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003195#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07003196 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07003197 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003198}
3199#endif /* __PAGETABLE_PMD_FOLDED */
3200
3201int make_pages_present(unsigned long addr, unsigned long end)
3202{
3203 int ret, len, write;
3204 struct vm_area_struct * vma;
3205
3206 vma = find_vma(current->mm, addr);
3207 if (!vma)
KOSAKI Motohiroa4770972008-08-04 13:41:14 -07003208 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003209 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02003210 BUG_ON(addr >= end);
3211 BUG_ON(end > vma->vm_end);
Rolf Eike Beer68e116a2007-07-15 23:38:03 -07003212 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003213 ret = get_user_pages(current, current->mm, addr,
3214 len, write, 0, NULL, NULL);
Lee Schermerhornc11d69d2008-10-18 20:26:56 -07003215 if (ret < 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003216 return ret;
Lee Schermerhorn9978ad52008-10-18 20:26:56 -07003217 return ret == len ? 0 : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003218}
3219
Linus Torvalds1da177e2005-04-16 15:20:36 -07003220#if !defined(__HAVE_ARCH_GATE_AREA)
3221
3222#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07003223static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003224
3225static int __init gate_vma_init(void)
3226{
3227 gate_vma.vm_mm = NULL;
3228 gate_vma.vm_start = FIXADDR_USER_START;
3229 gate_vma.vm_end = FIXADDR_USER_END;
Roland McGrathb6558c42007-01-26 00:56:47 -08003230 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
3231 gate_vma.vm_page_prot = __P101;
Roland McGrathf47aef52007-01-26 00:56:49 -08003232 /*
3233 * Make sure the vDSO gets into every core dump.
3234 * Dumping its contents makes post-mortem fully interpretable later
3235 * without matching up the same kernel and hardware config to see
3236 * what PC values meant.
3237 */
3238 gate_vma.vm_flags |= VM_ALWAYSDUMP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003239 return 0;
3240}
3241__initcall(gate_vma_init);
3242#endif
3243
3244struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
3245{
3246#ifdef AT_SYSINFO_EHDR
3247 return &gate_vma;
3248#else
3249 return NULL;
3250#endif
3251}
3252
3253int in_gate_area_no_task(unsigned long addr)
3254{
3255#ifdef AT_SYSINFO_EHDR
3256 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
3257 return 1;
3258#endif
3259 return 0;
3260}
3261
3262#endif /* __HAVE_ARCH_GATE_AREA */
David Howells0ec76a12006-09-27 01:50:15 -07003263
Johannes Weinerf8ad0f492009-06-16 15:32:33 -07003264static int follow_pte(struct mm_struct *mm, unsigned long address,
3265 pte_t **ptepp, spinlock_t **ptlp)
3266{
3267 pgd_t *pgd;
3268 pud_t *pud;
3269 pmd_t *pmd;
3270 pte_t *ptep;
3271
3272 pgd = pgd_offset(mm, address);
3273 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
3274 goto out;
3275
3276 pud = pud_offset(pgd, address);
3277 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
3278 goto out;
3279
3280 pmd = pmd_offset(pud, address);
3281 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
3282 goto out;
3283
3284 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
3285 if (pmd_huge(*pmd))
3286 goto out;
3287
3288 ptep = pte_offset_map_lock(mm, pmd, address, ptlp);
3289 if (!ptep)
3290 goto out;
3291 if (!pte_present(*ptep))
3292 goto unlock;
3293 *ptepp = ptep;
3294 return 0;
3295unlock:
3296 pte_unmap_unlock(ptep, *ptlp);
3297out:
3298 return -EINVAL;
3299}
3300
Johannes Weiner3b6748e2009-06-16 15:32:35 -07003301/**
3302 * follow_pfn - look up PFN at a user virtual address
3303 * @vma: memory mapping
3304 * @address: user virtual address
3305 * @pfn: location to store found PFN
3306 *
3307 * Only IO mappings and raw PFN mappings are allowed.
3308 *
3309 * Returns zero and the pfn at @pfn on success, -ve otherwise.
3310 */
3311int follow_pfn(struct vm_area_struct *vma, unsigned long address,
3312 unsigned long *pfn)
3313{
3314 int ret = -EINVAL;
3315 spinlock_t *ptl;
3316 pte_t *ptep;
3317
3318 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3319 return ret;
3320
3321 ret = follow_pte(vma->vm_mm, address, &ptep, &ptl);
3322 if (ret)
3323 return ret;
3324 *pfn = pte_pfn(*ptep);
3325 pte_unmap_unlock(ptep, ptl);
3326 return 0;
3327}
3328EXPORT_SYMBOL(follow_pfn);
3329
Rik van Riel28b2ee22008-07-23 21:27:05 -07003330#ifdef CONFIG_HAVE_IOREMAP_PROT
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003331int follow_phys(struct vm_area_struct *vma,
3332 unsigned long address, unsigned int flags,
3333 unsigned long *prot, resource_size_t *phys)
Rik van Riel28b2ee22008-07-23 21:27:05 -07003334{
Johannes Weiner03668a42009-06-16 15:32:34 -07003335 int ret = -EINVAL;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003336 pte_t *ptep, pte;
3337 spinlock_t *ptl;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003338
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003339 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
3340 goto out;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003341
Johannes Weiner03668a42009-06-16 15:32:34 -07003342 if (follow_pte(vma->vm_mm, address, &ptep, &ptl))
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003343 goto out;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003344 pte = *ptep;
Johannes Weiner03668a42009-06-16 15:32:34 -07003345
Rik van Riel28b2ee22008-07-23 21:27:05 -07003346 if ((flags & FOLL_WRITE) && !pte_write(pte))
3347 goto unlock;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003348
3349 *prot = pgprot_val(pte_pgprot(pte));
Johannes Weiner03668a42009-06-16 15:32:34 -07003350 *phys = (resource_size_t)pte_pfn(pte) << PAGE_SHIFT;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003351
Johannes Weiner03668a42009-06-16 15:32:34 -07003352 ret = 0;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003353unlock:
3354 pte_unmap_unlock(ptep, ptl);
3355out:
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003356 return ret;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003357}
3358
3359int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
3360 void *buf, int len, int write)
3361{
3362 resource_size_t phys_addr;
3363 unsigned long prot = 0;
KOSAKI Motohiro2bc72732009-01-06 14:39:43 -08003364 void __iomem *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003365 int offset = addr & (PAGE_SIZE-1);
3366
venkatesh.pallipadi@intel.comd87fe662008-12-19 13:47:27 -08003367 if (follow_phys(vma, addr, write, &prot, &phys_addr))
Rik van Riel28b2ee22008-07-23 21:27:05 -07003368 return -EINVAL;
3369
3370 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
3371 if (write)
3372 memcpy_toio(maddr + offset, buf, len);
3373 else
3374 memcpy_fromio(buf, maddr + offset, len);
3375 iounmap(maddr);
3376
3377 return len;
3378}
3379#endif
3380
David Howells0ec76a12006-09-27 01:50:15 -07003381/*
3382 * Access another process' address space.
3383 * Source/target buffer must be kernel space,
3384 * Do not walk the page table directly, use get_user_pages
3385 */
3386int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
3387{
3388 struct mm_struct *mm;
3389 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07003390 void *old_buf = buf;
3391
3392 mm = get_task_mm(tsk);
3393 if (!mm)
3394 return 0;
3395
3396 down_read(&mm->mmap_sem);
Simon Arlott183ff222007-10-20 01:27:18 +02003397 /* ignore errors, just check how much was successfully transferred */
David Howells0ec76a12006-09-27 01:50:15 -07003398 while (len) {
3399 int bytes, ret, offset;
3400 void *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07003401 struct page *page = NULL;
David Howells0ec76a12006-09-27 01:50:15 -07003402
3403 ret = get_user_pages(tsk, mm, addr, 1,
3404 write, 1, &page, &vma);
Rik van Riel28b2ee22008-07-23 21:27:05 -07003405 if (ret <= 0) {
3406 /*
3407 * Check if this is a VM_IO | VM_PFNMAP VMA, which
3408 * we can access using slightly different code.
3409 */
3410#ifdef CONFIG_HAVE_IOREMAP_PROT
3411 vma = find_vma(mm, addr);
3412 if (!vma)
3413 break;
3414 if (vma->vm_ops && vma->vm_ops->access)
3415 ret = vma->vm_ops->access(vma, addr, buf,
3416 len, write);
3417 if (ret <= 0)
3418#endif
3419 break;
3420 bytes = ret;
David Howells0ec76a12006-09-27 01:50:15 -07003421 } else {
Rik van Riel28b2ee22008-07-23 21:27:05 -07003422 bytes = len;
3423 offset = addr & (PAGE_SIZE-1);
3424 if (bytes > PAGE_SIZE-offset)
3425 bytes = PAGE_SIZE-offset;
3426
3427 maddr = kmap(page);
3428 if (write) {
3429 copy_to_user_page(vma, page, addr,
3430 maddr + offset, buf, bytes);
3431 set_page_dirty_lock(page);
3432 } else {
3433 copy_from_user_page(vma, page, addr,
3434 buf, maddr + offset, bytes);
3435 }
3436 kunmap(page);
3437 page_cache_release(page);
David Howells0ec76a12006-09-27 01:50:15 -07003438 }
David Howells0ec76a12006-09-27 01:50:15 -07003439 len -= bytes;
3440 buf += bytes;
3441 addr += bytes;
3442 }
3443 up_read(&mm->mmap_sem);
3444 mmput(mm);
3445
3446 return buf - old_buf;
3447}
Andi Kleen03252912008-01-30 13:33:18 +01003448
3449/*
3450 * Print the name of a VMA.
3451 */
3452void print_vma_addr(char *prefix, unsigned long ip)
3453{
3454 struct mm_struct *mm = current->mm;
3455 struct vm_area_struct *vma;
3456
Ingo Molnare8bff742008-02-13 20:21:06 +01003457 /*
3458 * Do not print if we are in atomic
3459 * contexts (in exception stacks, etc.):
3460 */
3461 if (preempt_count())
3462 return;
3463
Andi Kleen03252912008-01-30 13:33:18 +01003464 down_read(&mm->mmap_sem);
3465 vma = find_vma(mm, ip);
3466 if (vma && vma->vm_file) {
3467 struct file *f = vma->vm_file;
3468 char *buf = (char *)__get_free_page(GFP_KERNEL);
3469 if (buf) {
3470 char *p, *s;
3471
Jan Blunckcf28b482008-02-14 19:38:44 -08003472 p = d_path(&f->f_path, buf, PAGE_SIZE);
Andi Kleen03252912008-01-30 13:33:18 +01003473 if (IS_ERR(p))
3474 p = "?";
3475 s = strrchr(p, '/');
3476 if (s)
3477 p = s+1;
3478 printk("%s%s[%lx+%lx]", prefix, p,
3479 vma->vm_start,
3480 vma->vm_end - vma->vm_start);
3481 free_page((unsigned long)buf);
3482 }
3483 }
3484 up_read(&current->mm->mmap_sem);
3485}
Nick Piggin3ee1afa2008-09-10 13:37:17 +02003486
3487#ifdef CONFIG_PROVE_LOCKING
3488void might_fault(void)
3489{
Peter Zijlstra95156f02009-01-12 13:02:11 +01003490 /*
3491 * Some code (nfs/sunrpc) uses socket ops on kernel memory while
3492 * holding the mmap_sem, this is safe because kernel memory doesn't
3493 * get paged out, therefore we'll never actually fault, and the
3494 * below annotations will generate false positives.
3495 */
3496 if (segment_eq(get_fs(), KERNEL_DS))
3497 return;
3498
Nick Piggin3ee1afa2008-09-10 13:37:17 +02003499 might_sleep();
3500 /*
3501 * it would be nicer only to annotate paths which are not under
3502 * pagefault_disable, however that requires a larger audit and
3503 * providing helpers like get_user_atomic.
3504 */
3505 if (!in_atomic() && current->mm)
3506 might_lock_read(&current->mm->mmap_sem);
3507}
3508EXPORT_SYMBOL(might_fault);
3509#endif