blob: 262e3eb6601a7ca1601c16a69d82814e7a9ea52b [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/memory.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
6
7/*
8 * demand-loading started 01.12.91 - seems it is high on the list of
9 * things wanted, and it should be easy to implement. - Linus
10 */
11
12/*
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
15 *
16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 * would have taken more than the 6M I have free, but it worked well as
18 * far as I could see.
19 *
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
21 */
22
23/*
24 * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 * thought has to go into this. Oh, well..
26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 * Found it. Everything seems to work now.
28 * 20.12.91 - Ok, making the swap-device changeable like the root.
29 */
30
31/*
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
34 *
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
37 *
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
39 */
40
41#include <linux/kernel_stat.h>
42#include <linux/mm.h>
43#include <linux/hugetlb.h>
44#include <linux/mman.h>
45#include <linux/swap.h>
46#include <linux/highmem.h>
47#include <linux/pagemap.h>
48#include <linux/rmap.h>
49#include <linux/module.h>
Shailabh Nagar0ff92242006-07-14 00:24:37 -070050#include <linux/delayacct.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051#include <linux/init.h>
Peter Zijlstraedc79b22006-09-25 23:30:58 -070052#include <linux/writeback.h>
Balbir Singh8a9f3cc2008-02-07 00:13:53 -080053#include <linux/memcontrol.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070054
55#include <asm/pgalloc.h>
56#include <asm/uaccess.h>
57#include <asm/tlb.h>
58#include <asm/tlbflush.h>
59#include <asm/pgtable.h>
60
61#include <linux/swapops.h>
62#include <linux/elf.h>
63
Jan Beulich42b77722008-07-23 21:27:10 -070064#include "internal.h"
65
Andy Whitcroftd41dee32005-06-23 00:07:54 -070066#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070067/* use the per-pgdat data instead for discontigmem - mbligh */
68unsigned long max_mapnr;
69struct page *mem_map;
70
71EXPORT_SYMBOL(max_mapnr);
72EXPORT_SYMBOL(mem_map);
73#endif
74
75unsigned long num_physpages;
76/*
77 * A number of key systems in x86 including ioremap() rely on the assumption
78 * that high_memory defines the upper bound on direct map memory, then end
79 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
80 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
81 * and ZONE_HIGHMEM.
82 */
83void * high_memory;
Linus Torvalds1da177e2005-04-16 15:20:36 -070084
85EXPORT_SYMBOL(num_physpages);
86EXPORT_SYMBOL(high_memory);
Linus Torvalds1da177e2005-04-16 15:20:36 -070087
Ingo Molnar32a93232008-02-06 22:39:44 +010088/*
89 * Randomize the address space (stacks, mmaps, brk, etc.).
90 *
91 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
92 * as ancient (libc5 based) binaries can segfault. )
93 */
94int randomize_va_space __read_mostly =
95#ifdef CONFIG_COMPAT_BRK
96 1;
97#else
98 2;
99#endif
Andi Kleena62eaf12006-02-16 23:41:58 +0100100
101static int __init disable_randmaps(char *s)
102{
103 randomize_va_space = 0;
OGAWA Hirofumi9b410462006-03-31 02:30:33 -0800104 return 1;
Andi Kleena62eaf12006-02-16 23:41:58 +0100105}
106__setup("norandmaps", disable_randmaps);
107
108
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109/*
110 * If a p?d_bad entry is found while walking page tables, report
111 * the error, before resetting entry to p?d_none. Usually (but
112 * very seldom) called out from the p?d_none_or_clear_bad macros.
113 */
114
115void pgd_clear_bad(pgd_t *pgd)
116{
117 pgd_ERROR(*pgd);
118 pgd_clear(pgd);
119}
120
121void pud_clear_bad(pud_t *pud)
122{
123 pud_ERROR(*pud);
124 pud_clear(pud);
125}
126
127void pmd_clear_bad(pmd_t *pmd)
128{
129 pmd_ERROR(*pmd);
130 pmd_clear(pmd);
131}
132
133/*
134 * Note: this doesn't free the actual pages themselves. That
135 * has been handled earlier when unmapping all the memory regions.
136 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700137static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800139 pgtable_t token = pmd_pgtable(*pmd);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700140 pmd_clear(pmd);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800141 pte_free_tlb(tlb, token);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700142 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143}
144
Hugh Dickinse0da3822005-04-19 13:29:15 -0700145static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
146 unsigned long addr, unsigned long end,
147 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148{
149 pmd_t *pmd;
150 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700151 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152
Hugh Dickinse0da3822005-04-19 13:29:15 -0700153 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 do {
156 next = pmd_addr_end(addr, end);
157 if (pmd_none_or_clear_bad(pmd))
158 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700159 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160 } while (pmd++, addr = next, addr != end);
161
Hugh Dickinse0da3822005-04-19 13:29:15 -0700162 start &= PUD_MASK;
163 if (start < floor)
164 return;
165 if (ceiling) {
166 ceiling &= PUD_MASK;
167 if (!ceiling)
168 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700170 if (end - 1 > ceiling - 1)
171 return;
172
173 pmd = pmd_offset(pud, start);
174 pud_clear(pud);
175 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176}
177
Hugh Dickinse0da3822005-04-19 13:29:15 -0700178static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
179 unsigned long addr, unsigned long end,
180 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700181{
182 pud_t *pud;
183 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700184 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185
Hugh Dickinse0da3822005-04-19 13:29:15 -0700186 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 do {
189 next = pud_addr_end(addr, end);
190 if (pud_none_or_clear_bad(pud))
191 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700192 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 } while (pud++, addr = next, addr != end);
194
Hugh Dickinse0da3822005-04-19 13:29:15 -0700195 start &= PGDIR_MASK;
196 if (start < floor)
197 return;
198 if (ceiling) {
199 ceiling &= PGDIR_MASK;
200 if (!ceiling)
201 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700202 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700203 if (end - 1 > ceiling - 1)
204 return;
205
206 pud = pud_offset(pgd, start);
207 pgd_clear(pgd);
208 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209}
210
211/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700212 * This function frees user-level page tables of a process.
213 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 * Must be called with pagetable lock held.
215 */
Jan Beulich42b77722008-07-23 21:27:10 -0700216void free_pgd_range(struct mmu_gather *tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700217 unsigned long addr, unsigned long end,
218 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219{
220 pgd_t *pgd;
221 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700222 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223
Hugh Dickinse0da3822005-04-19 13:29:15 -0700224 /*
225 * The next few lines have given us lots of grief...
226 *
227 * Why are we testing PMD* at this top level? Because often
228 * there will be no work to do at all, and we'd prefer not to
229 * go all the way down to the bottom just to discover that.
230 *
231 * Why all these "- 1"s? Because 0 represents both the bottom
232 * of the address space and the top of it (using -1 for the
233 * top wouldn't help much: the masks would do the wrong thing).
234 * The rule is that addr 0 and floor 0 refer to the bottom of
235 * the address space, but end 0 and ceiling 0 refer to the top
236 * Comparisons need to use "end - 1" and "ceiling - 1" (though
237 * that end 0 case should be mythical).
238 *
239 * Wherever addr is brought up or ceiling brought down, we must
240 * be careful to reject "the opposite 0" before it confuses the
241 * subsequent tests. But what about where end is brought down
242 * by PMD_SIZE below? no, end can't go down to 0 there.
243 *
244 * Whereas we round start (addr) and ceiling down, by different
245 * masks at different levels, in order to test whether a table
246 * now has no other vmas using it, so can be freed, we don't
247 * bother to round floor or end up - the tests don't need that.
248 */
249
250 addr &= PMD_MASK;
251 if (addr < floor) {
252 addr += PMD_SIZE;
253 if (!addr)
254 return;
255 }
256 if (ceiling) {
257 ceiling &= PMD_MASK;
258 if (!ceiling)
259 return;
260 }
261 if (end - 1 > ceiling - 1)
262 end -= PMD_SIZE;
263 if (addr > end - 1)
264 return;
265
266 start = addr;
Jan Beulich42b77722008-07-23 21:27:10 -0700267 pgd = pgd_offset(tlb->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 do {
269 next = pgd_addr_end(addr, end);
270 if (pgd_none_or_clear_bad(pgd))
271 continue;
Jan Beulich42b77722008-07-23 21:27:10 -0700272 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700274}
275
Jan Beulich42b77722008-07-23 21:27:10 -0700276void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700277 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700278{
279 while (vma) {
280 struct vm_area_struct *next = vma->vm_next;
281 unsigned long addr = vma->vm_start;
282
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700283 /*
284 * Hide vma from rmap and vmtruncate before freeing pgtables
285 */
286 anon_vma_unlink(vma);
287 unlink_file_vma(vma);
288
David Gibson9da61ae2006-03-22 00:08:57 -0800289 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700290 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700291 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700292 } else {
293 /*
294 * Optimization: gather nearby vmas into one call down
295 */
296 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800297 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700298 vma = next;
299 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700300 anon_vma_unlink(vma);
301 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700302 }
303 free_pgd_range(tlb, addr, vma->vm_end,
304 floor, next? next->vm_start: ceiling);
305 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700306 vma = next;
307 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700308}
309
Hugh Dickins1bb36302005-10-29 18:16:22 -0700310int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800312 pgtable_t new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700313 if (!new)
314 return -ENOMEM;
315
Nick Piggin362a61a2008-05-14 06:37:36 +0200316 /*
317 * Ensure all pte setup (eg. pte page lock and page clearing) are
318 * visible before the pte is made visible to other CPUs by being
319 * put into page tables.
320 *
321 * The other side of the story is the pointer chasing in the page
322 * table walking code (when walking the page table without locking;
323 * ie. most of the time). Fortunately, these data accesses consist
324 * of a chain of data-dependent loads, meaning most CPUs (alpha
325 * being the notable exception) will already guarantee loads are
326 * seen in-order. See the alpha page table accessors for the
327 * smp_read_barrier_depends() barriers in page table walking code.
328 */
329 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
330
Hugh Dickinsc74df322005-10-29 18:16:23 -0700331 spin_lock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800332 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700333 mm->nr_ptes++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 pmd_populate(mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800335 new = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700337 spin_unlock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800338 if (new)
339 pte_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700340 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341}
342
Hugh Dickins1bb36302005-10-29 18:16:22 -0700343int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700345 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
346 if (!new)
347 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348
Nick Piggin362a61a2008-05-14 06:37:36 +0200349 smp_wmb(); /* See comment in __pte_alloc */
350
Hugh Dickins1bb36302005-10-29 18:16:22 -0700351 spin_lock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800352 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Hugh Dickins1bb36302005-10-29 18:16:22 -0700353 pmd_populate_kernel(&init_mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800354 new = NULL;
355 }
Hugh Dickins1bb36302005-10-29 18:16:22 -0700356 spin_unlock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800357 if (new)
358 pte_free_kernel(&init_mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700359 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360}
361
Hugh Dickinsae859762005-10-29 18:16:05 -0700362static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
363{
364 if (file_rss)
365 add_mm_counter(mm, file_rss, file_rss);
366 if (anon_rss)
367 add_mm_counter(mm, anon_rss, anon_rss);
368}
369
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800371 * This function is called to print an error when a bad pte
372 * is found. For example, we might have a PFN-mapped pte in
373 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700374 *
375 * The calling function must still handle the error.
376 */
377void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
378{
379 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
380 "vm_flags = %lx, vaddr = %lx\n",
381 (long long)pte_val(pte),
382 (vma->vm_mm == current->mm ? current->comm : "???"),
383 vma->vm_flags, vaddr);
384 dump_stack();
385}
386
Linus Torvalds67121172005-12-11 20:38:17 -0800387static inline int is_cow_mapping(unsigned int flags)
388{
389 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
390}
391
Nick Pigginb5810032005-10-29 18:16:12 -0700392/*
Nick Piggin7e675132008-04-28 02:13:00 -0700393 * vm_normal_page -- This function gets the "struct page" associated with a pte.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800394 *
Nick Piggin7e675132008-04-28 02:13:00 -0700395 * "Special" mappings do not wish to be associated with a "struct page" (either
396 * it doesn't exist, or it exists but they don't want to touch it). In this
397 * case, NULL is returned here. "Normal" mappings do have a struct page.
Jared Hulbertb379d792008-04-28 02:12:58 -0700398 *
Nick Piggin7e675132008-04-28 02:13:00 -0700399 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
400 * pte bit, in which case this function is trivial. Secondly, an architecture
401 * may not have a spare pte bit, which requires a more complicated scheme,
402 * described below.
403 *
404 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
405 * special mapping (even if there are underlying and valid "struct pages").
406 * COWed pages of a VM_PFNMAP are always normal.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800407 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700408 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
409 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
Nick Piggin7e675132008-04-28 02:13:00 -0700410 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
411 * mapping will always honor the rule
Linus Torvalds6aab3412005-11-28 14:34:23 -0800412 *
413 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
414 *
Nick Piggin7e675132008-04-28 02:13:00 -0700415 * And for normal mappings this is false.
Jared Hulbertb379d792008-04-28 02:12:58 -0700416 *
Nick Piggin7e675132008-04-28 02:13:00 -0700417 * This restricts such mappings to be a linear translation from virtual address
418 * to pfn. To get around this restriction, we allow arbitrary mappings so long
419 * as the vma is not a COW mapping; in that case, we know that all ptes are
420 * special (because none can have been COWed).
Jared Hulbertb379d792008-04-28 02:12:58 -0700421 *
422 *
Nick Piggin7e675132008-04-28 02:13:00 -0700423 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
424 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700425 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
426 * page" backing, however the difference is that _all_ pages with a struct
427 * page (that is, those where pfn_valid is true) are refcounted and considered
428 * normal pages by the VM. The disadvantage is that pages are refcounted
429 * (which can be slower and simply not an option for some PFNMAP users). The
430 * advantage is that we don't have to follow the strict linearity rule of
431 * PFNMAP mappings in order to support COWable mappings.
432 *
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800433 */
Nick Piggin7e675132008-04-28 02:13:00 -0700434#ifdef __HAVE_ARCH_PTE_SPECIAL
435# define HAVE_PTE_SPECIAL 1
436#else
437# define HAVE_PTE_SPECIAL 0
438#endif
439struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
440 pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800441{
Nick Piggin7e675132008-04-28 02:13:00 -0700442 unsigned long pfn;
443
444 if (HAVE_PTE_SPECIAL) {
445 if (likely(!pte_special(pte))) {
446 VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
447 return pte_page(pte);
448 }
449 VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
450 return NULL;
451 }
452
453 /* !HAVE_PTE_SPECIAL case follows: */
454
455 pfn = pte_pfn(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800456
Jared Hulbertb379d792008-04-28 02:12:58 -0700457 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
458 if (vma->vm_flags & VM_MIXEDMAP) {
459 if (!pfn_valid(pfn))
460 return NULL;
461 goto out;
462 } else {
Nick Piggin7e675132008-04-28 02:13:00 -0700463 unsigned long off;
464 off = (addr - vma->vm_start) >> PAGE_SHIFT;
Jared Hulbertb379d792008-04-28 02:12:58 -0700465 if (pfn == vma->vm_pgoff + off)
466 return NULL;
467 if (!is_cow_mapping(vma->vm_flags))
468 return NULL;
469 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800470 }
471
Nick Piggin7e675132008-04-28 02:13:00 -0700472 VM_BUG_ON(!pfn_valid(pfn));
Linus Torvalds6aab3412005-11-28 14:34:23 -0800473
474 /*
Nick Piggin7e675132008-04-28 02:13:00 -0700475 * NOTE! We still have PageReserved() pages in the page tables.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800476 *
Nick Piggin7e675132008-04-28 02:13:00 -0700477 * eg. VDSO mappings can cause them to exist.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800478 */
Jared Hulbertb379d792008-04-28 02:12:58 -0700479out:
Linus Torvalds6aab3412005-11-28 14:34:23 -0800480 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800481}
482
483/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 * copy one vm_area from one task to the other. Assumes the page tables
485 * already present in the new task to be cleared in the whole range
486 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 */
488
Hugh Dickins8c103762005-10-29 18:16:13 -0700489static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700491 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700492 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493{
Nick Pigginb5810032005-10-29 18:16:12 -0700494 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 pte_t pte = *src_pte;
496 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497
498 /* pte contains position in swap or file, so copy. */
499 if (unlikely(!pte_present(pte))) {
500 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700501 swp_entry_t entry = pte_to_swp_entry(pte);
502
503 swap_duplicate(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 /* make sure dst_mm is on swapoff's mmlist. */
505 if (unlikely(list_empty(&dst_mm->mmlist))) {
506 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700507 if (list_empty(&dst_mm->mmlist))
508 list_add(&dst_mm->mmlist,
509 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 spin_unlock(&mmlist_lock);
511 }
Christoph Lameter06972122006-06-23 02:03:35 -0700512 if (is_write_migration_entry(entry) &&
513 is_cow_mapping(vm_flags)) {
514 /*
515 * COW mappings require pages in both parent
516 * and child to be set to read.
517 */
518 make_migration_entry_read(&entry);
519 pte = swp_entry_to_pte(entry);
520 set_pte_at(src_mm, addr, src_pte, pte);
521 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700523 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
525
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 /*
527 * If it's a COW mapping, write protect it both
528 * in the parent and the child
529 */
Linus Torvalds67121172005-12-11 20:38:17 -0800530 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 ptep_set_wrprotect(src_mm, addr, src_pte);
Zachary Amsden3dc90792006-09-30 23:29:30 -0700532 pte = pte_wrprotect(pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 }
534
535 /*
536 * If it's a shared mapping, mark it clean in
537 * the child
538 */
539 if (vm_flags & VM_SHARED)
540 pte = pte_mkclean(pte);
541 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800542
543 page = vm_normal_page(vma, addr, pte);
544 if (page) {
545 get_page(page);
Nick Pigginc97a9e12007-05-16 22:11:21 -0700546 page_dup_rmap(page, vma, addr);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800547 rss[!!PageAnon(page)]++;
548 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700549
550out_set_pte:
551 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552}
553
554static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
555 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
556 unsigned long addr, unsigned long end)
557{
558 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700559 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700560 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700561 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562
563again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700564 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700565 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 if (!dst_pte)
567 return -ENOMEM;
568 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700569 src_ptl = pte_lockptr(src_mm, src_pmd);
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700570 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700571 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 do {
574 /*
575 * We are holding two locks at this point - either of them
576 * could generate latencies in another task on another CPU.
577 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700578 if (progress >= 32) {
579 progress = 0;
580 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100581 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700582 break;
583 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 if (pte_none(*src_pte)) {
585 progress++;
586 continue;
587 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700588 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 progress += 8;
590 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700592 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -0700593 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700595 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700596 pte_unmap_unlock(dst_pte - 1, dst_ptl);
597 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 if (addr != end)
599 goto again;
600 return 0;
601}
602
603static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
604 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
605 unsigned long addr, unsigned long end)
606{
607 pmd_t *src_pmd, *dst_pmd;
608 unsigned long next;
609
610 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
611 if (!dst_pmd)
612 return -ENOMEM;
613 src_pmd = pmd_offset(src_pud, addr);
614 do {
615 next = pmd_addr_end(addr, end);
616 if (pmd_none_or_clear_bad(src_pmd))
617 continue;
618 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
619 vma, addr, next))
620 return -ENOMEM;
621 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
622 return 0;
623}
624
625static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
626 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
627 unsigned long addr, unsigned long end)
628{
629 pud_t *src_pud, *dst_pud;
630 unsigned long next;
631
632 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
633 if (!dst_pud)
634 return -ENOMEM;
635 src_pud = pud_offset(src_pgd, addr);
636 do {
637 next = pud_addr_end(addr, end);
638 if (pud_none_or_clear_bad(src_pud))
639 continue;
640 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
641 vma, addr, next))
642 return -ENOMEM;
643 } while (dst_pud++, src_pud++, addr = next, addr != end);
644 return 0;
645}
646
647int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
648 struct vm_area_struct *vma)
649{
650 pgd_t *src_pgd, *dst_pgd;
651 unsigned long next;
652 unsigned long addr = vma->vm_start;
653 unsigned long end = vma->vm_end;
654
Nick Piggind9928952005-08-28 16:49:11 +1000655 /*
656 * Don't copy ptes where a page fault will fill them correctly.
657 * Fork becomes much lighter when there are big shared or private
658 * readonly mappings. The tradeoff is that copy_page_range is more
659 * efficient than faulting.
660 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800661 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000662 if (!vma->anon_vma)
663 return 0;
664 }
665
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 if (is_vm_hugetlb_page(vma))
667 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
668
669 dst_pgd = pgd_offset(dst_mm, addr);
670 src_pgd = pgd_offset(src_mm, addr);
671 do {
672 next = pgd_addr_end(addr, end);
673 if (pgd_none_or_clear_bad(src_pgd))
674 continue;
675 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
676 vma, addr, next))
677 return -ENOMEM;
678 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
679 return 0;
680}
681
Robin Holt51c6f662005-11-13 16:06:42 -0800682static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700683 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800685 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686{
Nick Pigginb5810032005-10-29 18:16:12 -0700687 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700689 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700690 int file_rss = 0;
691 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700692
Hugh Dickins508034a2005-10-29 18:16:30 -0700693 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700694 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695 do {
696 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800697 if (pte_none(ptent)) {
698 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800700 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800701
702 (*zap_work) -= PAGE_SIZE;
703
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800705 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800706
Linus Torvalds6aab3412005-11-28 14:34:23 -0800707 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700708 if (unlikely(details) && page) {
709 /*
710 * unmap_shared_mapping_pages() wants to
711 * invalidate cache without truncating:
712 * unmap shared but keep private pages.
713 */
714 if (details->check_mapping &&
715 details->check_mapping != page->mapping)
716 continue;
717 /*
718 * Each page->index must be checked when
719 * invalidating or truncating nonlinear.
720 */
721 if (details->nonlinear_vma &&
722 (page->index < details->first_index ||
723 page->index > details->last_index))
724 continue;
725 }
Nick Pigginb5810032005-10-29 18:16:12 -0700726 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700727 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 tlb_remove_tlb_entry(tlb, pte, addr);
729 if (unlikely(!page))
730 continue;
731 if (unlikely(details) && details->nonlinear_vma
732 && linear_page_index(details->nonlinear_vma,
733 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700734 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700737 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700738 else {
739 if (pte_dirty(ptent))
740 set_page_dirty(page);
741 if (pte_young(ptent))
Ken Chendaa88c82007-02-10 01:43:18 -0800742 SetPageReferenced(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700743 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700744 }
Nick Piggin7de6b802006-12-22 01:09:33 -0800745 page_remove_rmap(page, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 tlb_remove_page(tlb, page);
747 continue;
748 }
749 /*
750 * If details->check_mapping, we leave swap entries;
751 * if details->nonlinear_vma, we leave file entries.
752 */
753 if (unlikely(details))
754 continue;
755 if (!pte_file(ptent))
756 free_swap_and_cache(pte_to_swp_entry(ptent));
Zachary Amsden9888a1c2006-09-30 23:29:31 -0700757 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800758 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700759
Hugh Dickins86d912f2005-10-29 18:16:14 -0700760 add_mm_rss(mm, file_rss, anon_rss);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700761 arch_leave_lazy_mmu_mode();
Hugh Dickins508034a2005-10-29 18:16:30 -0700762 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800763
764 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765}
766
Robin Holt51c6f662005-11-13 16:06:42 -0800767static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700768 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800770 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771{
772 pmd_t *pmd;
773 unsigned long next;
774
775 pmd = pmd_offset(pud, addr);
776 do {
777 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800778 if (pmd_none_or_clear_bad(pmd)) {
779 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800781 }
782 next = zap_pte_range(tlb, vma, pmd, addr, next,
783 zap_work, details);
784 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
785
786 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787}
788
Robin Holt51c6f662005-11-13 16:06:42 -0800789static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700790 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800792 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700793{
794 pud_t *pud;
795 unsigned long next;
796
797 pud = pud_offset(pgd, addr);
798 do {
799 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800800 if (pud_none_or_clear_bad(pud)) {
801 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800803 }
804 next = zap_pmd_range(tlb, vma, pud, addr, next,
805 zap_work, details);
806 } while (pud++, addr = next, (addr != end && *zap_work > 0));
807
808 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700809}
810
Robin Holt51c6f662005-11-13 16:06:42 -0800811static unsigned long unmap_page_range(struct mmu_gather *tlb,
812 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800814 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815{
816 pgd_t *pgd;
817 unsigned long next;
818
819 if (details && !details->check_mapping && !details->nonlinear_vma)
820 details = NULL;
821
822 BUG_ON(addr >= end);
823 tlb_start_vma(tlb, vma);
824 pgd = pgd_offset(vma->vm_mm, addr);
825 do {
826 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800827 if (pgd_none_or_clear_bad(pgd)) {
828 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800830 }
831 next = zap_pud_range(tlb, vma, pgd, addr, next,
832 zap_work, details);
833 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800835
836 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700837}
838
839#ifdef CONFIG_PREEMPT
840# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
841#else
842/* No preempt: go for improved straight-line efficiency */
843# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
844#endif
845
846/**
847 * unmap_vmas - unmap a range of memory covered by a list of vma's
848 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700849 * @vma: the starting vma
850 * @start_addr: virtual address at which to start unmapping
851 * @end_addr: virtual address at which to end unmapping
852 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
853 * @details: details of nonlinear truncation or shared cache invalidation
854 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700855 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700857 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700859 * We aim to not hold locks for too long (for scheduling latency reasons).
860 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861 * return the ending mmu_gather to the caller.
862 *
863 * Only addresses between `start' and `end' will be unmapped.
864 *
865 * The VMA list must be sorted in ascending virtual address order.
866 *
867 * unmap_vmas() assumes that the caller will flush the whole unmapped address
868 * range after unmap_vmas() returns. So the only responsibility here is to
869 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
870 * drops the lock and schedules.
871 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700872unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 struct vm_area_struct *vma, unsigned long start_addr,
874 unsigned long end_addr, unsigned long *nr_accounted,
875 struct zap_details *details)
876{
Robin Holt51c6f662005-11-13 16:06:42 -0800877 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
879 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700880 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700882 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700883
884 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 unsigned long end;
886
887 start = max(vma->vm_start, start_addr);
888 if (start >= vma->vm_end)
889 continue;
890 end = min(vma->vm_end, end_addr);
891 if (end <= vma->vm_start)
892 continue;
893
894 if (vma->vm_flags & VM_ACCOUNT)
895 *nr_accounted += (end - start) >> PAGE_SHIFT;
896
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 if (!tlb_start_valid) {
899 tlb_start = start;
900 tlb_start_valid = 1;
901 }
902
Robin Holt51c6f662005-11-13 16:06:42 -0800903 if (unlikely(is_vm_hugetlb_page(vma))) {
Andi Kleena137e1c2008-07-23 21:27:43 -0700904 /*
905 * It is undesirable to test vma->vm_file as it
906 * should be non-null for valid hugetlb area.
907 * However, vm_file will be NULL in the error
908 * cleanup path of do_mmap_pgoff. When
909 * hugetlbfs ->mmap method fails,
910 * do_mmap_pgoff() nullifies vma->vm_file
911 * before calling this function to clean up.
912 * Since no pte has actually been setup, it is
913 * safe to do nothing in this case.
914 */
915 if (vma->vm_file) {
916 unmap_hugepage_range(vma, start, end, NULL);
917 zap_work -= (end - start) /
Andi Kleena5516432008-07-23 21:27:41 -0700918 pages_per_huge_page(hstate_vma(vma));
Andi Kleena137e1c2008-07-23 21:27:43 -0700919 }
920
Robin Holt51c6f662005-11-13 16:06:42 -0800921 start = end;
922 } else
923 start = unmap_page_range(*tlbp, vma,
924 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700925
Robin Holt51c6f662005-11-13 16:06:42 -0800926 if (zap_work > 0) {
927 BUG_ON(start != end);
928 break;
929 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700930
931 tlb_finish_mmu(*tlbp, tlb_start, start);
932
933 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100934 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700936 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937 goto out;
938 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700939 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700940 }
941
Hugh Dickins508034a2005-10-29 18:16:30 -0700942 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800944 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700945 }
946 }
947out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700948 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949}
950
951/**
952 * zap_page_range - remove user pages in a given range
953 * @vma: vm_area_struct holding the applicable pages
954 * @address: starting address of pages to zap
955 * @size: number of bytes to zap
956 * @details: details of nonlinear truncation or shared cache invalidation
957 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700958unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959 unsigned long size, struct zap_details *details)
960{
961 struct mm_struct *mm = vma->vm_mm;
962 struct mmu_gather *tlb;
963 unsigned long end = address + size;
964 unsigned long nr_accounted = 0;
965
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700968 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700969 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
970 if (tlb)
971 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700972 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973}
974
975/*
976 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800978struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700979 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980{
981 pgd_t *pgd;
982 pud_t *pud;
983 pmd_t *pmd;
984 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700985 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800987 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700989 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
990 if (!IS_ERR(page)) {
991 BUG_ON(flags & FOLL_GET);
992 goto out;
993 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700994
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700995 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700996 pgd = pgd_offset(mm, address);
997 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700998 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700999
1000 pud = pud_offset(pgd, address);
Andi Kleenceb86872008-07-23 21:27:50 -07001001 if (pud_none(*pud))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001002 goto no_page_table;
Andi Kleenceb86872008-07-23 21:27:50 -07001003 if (pud_huge(*pud)) {
1004 BUG_ON(flags & FOLL_GET);
1005 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1006 goto out;
1007 }
1008 if (unlikely(pud_bad(*pud)))
1009 goto no_page_table;
1010
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 pmd = pmd_offset(pud, address);
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001012 if (pmd_none(*pmd))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001013 goto no_page_table;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001014 if (pmd_huge(*pmd)) {
1015 BUG_ON(flags & FOLL_GET);
1016 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1017 goto out;
1018 }
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001019 if (unlikely(pmd_bad(*pmd)))
1020 goto no_page_table;
1021
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001022 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023
1024 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001025 if (!pte_present(pte))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001026 goto no_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001027 if ((flags & FOLL_WRITE) && !pte_write(pte))
1028 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001029 page = vm_normal_page(vma, address, pte);
1030 if (unlikely(!page))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001031 goto bad_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001032
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001033 if (flags & FOLL_GET)
1034 get_page(page);
1035 if (flags & FOLL_TOUCH) {
1036 if ((flags & FOLL_WRITE) &&
1037 !pte_dirty(pte) && !PageDirty(page))
1038 set_page_dirty(page);
1039 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001040 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001041unlock:
1042 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001043out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001044 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001046bad_page:
1047 pte_unmap_unlock(ptep, ptl);
1048 return ERR_PTR(-EFAULT);
1049
1050no_page:
1051 pte_unmap_unlock(ptep, ptl);
1052 if (!pte_none(pte))
1053 return page;
1054 /* Fall through to ZERO_PAGE handling */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001055no_page_table:
1056 /*
1057 * When core dumping an enormous anonymous area that nobody
1058 * has touched so far, we don't want to allocate page tables.
1059 */
1060 if (flags & FOLL_ANON) {
Nick Piggin557ed1f2007-10-16 01:24:40 -07001061 page = ZERO_PAGE(0);
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001062 if (flags & FOLL_GET)
1063 get_page(page);
1064 BUG_ON(flags & FOLL_WRITE);
1065 }
1066 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067}
1068
Linus Torvalds672ca282008-06-23 11:21:37 -07001069/* Can we do the FOLL_ANON optimization? */
1070static inline int use_zero_page(struct vm_area_struct *vma)
1071{
1072 /*
1073 * We don't want to optimize FOLL_ANON for make_pages_present()
1074 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
1075 * we want to get the page from the page tables to make sure
1076 * that we serialize and update with any other user of that
1077 * mapping.
1078 */
1079 if (vma->vm_flags & (VM_LOCKED | VM_SHARED))
1080 return 0;
1081 /*
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001082 * And if we have a fault routine, it's not an anonymous region.
Linus Torvalds672ca282008-06-23 11:21:37 -07001083 */
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001084 return !vma->vm_ops || !vma->vm_ops->fault;
Linus Torvalds672ca282008-06-23 11:21:37 -07001085}
1086
Linus Torvalds1da177e2005-04-16 15:20:36 -07001087int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1088 unsigned long start, int len, int write, int force,
1089 struct page **pages, struct vm_area_struct **vmas)
1090{
1091 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001092 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001093
Jonathan Corbet900cf082008-02-11 16:17:33 -07001094 if (len <= 0)
1095 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001096 /*
1097 * Require read or write permissions.
1098 * If 'force' is set, we only require the "MAY" flags.
1099 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001100 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1101 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001102 i = 0;
1103
1104 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001105 struct vm_area_struct *vma;
1106 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107
1108 vma = find_extend_vma(mm, start);
1109 if (!vma && in_gate_area(tsk, start)) {
1110 unsigned long pg = start & PAGE_MASK;
1111 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1112 pgd_t *pgd;
1113 pud_t *pud;
1114 pmd_t *pmd;
1115 pte_t *pte;
1116 if (write) /* user gate pages are read-only */
1117 return i ? : -EFAULT;
1118 if (pg > TASK_SIZE)
1119 pgd = pgd_offset_k(pg);
1120 else
1121 pgd = pgd_offset_gate(mm, pg);
1122 BUG_ON(pgd_none(*pgd));
1123 pud = pud_offset(pgd, pg);
1124 BUG_ON(pud_none(*pud));
1125 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001126 if (pmd_none(*pmd))
1127 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001128 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001129 if (pte_none(*pte)) {
1130 pte_unmap(pte);
1131 return i ? : -EFAULT;
1132 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001133 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001134 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001135 pages[i] = page;
1136 if (page)
1137 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138 }
1139 pte_unmap(pte);
1140 if (vmas)
1141 vmas[i] = gate_vma;
1142 i++;
1143 start += PAGE_SIZE;
1144 len--;
1145 continue;
1146 }
1147
Linus Torvalds1ff80382005-12-12 16:24:33 -08001148 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001149 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001150 return i ? : -EFAULT;
1151
1152 if (is_vm_hugetlb_page(vma)) {
1153 i = follow_hugetlb_page(mm, vma, pages, vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -08001154 &start, &len, i, write);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001155 continue;
1156 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001157
1158 foll_flags = FOLL_TOUCH;
1159 if (pages)
1160 foll_flags |= FOLL_GET;
Linus Torvalds672ca282008-06-23 11:21:37 -07001161 if (!write && use_zero_page(vma))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001162 foll_flags |= FOLL_ANON;
1163
Linus Torvalds1da177e2005-04-16 15:20:36 -07001164 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001165 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001166
Ethan Solomita462e00c2007-07-15 23:38:16 -07001167 /*
1168 * If tsk is ooming, cut off its access to large memory
1169 * allocations. It has a pending SIGKILL, but it can't
1170 * be processed until returning to user space.
1171 */
1172 if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
Oleg Nesterov7a36a752008-07-04 09:59:28 -07001173 return i ? i : -ENOMEM;
Ethan Solomita462e00c2007-07-15 23:38:16 -07001174
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001175 if (write)
1176 foll_flags |= FOLL_WRITE;
1177
1178 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001179 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001180 int ret;
Nick Piggin83c54072007-07-19 01:47:05 -07001181 ret = handle_mm_fault(mm, vma, start,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001182 foll_flags & FOLL_WRITE);
Nick Piggin83c54072007-07-19 01:47:05 -07001183 if (ret & VM_FAULT_ERROR) {
1184 if (ret & VM_FAULT_OOM)
1185 return i ? i : -ENOMEM;
1186 else if (ret & VM_FAULT_SIGBUS)
1187 return i ? i : -EFAULT;
1188 BUG();
1189 }
1190 if (ret & VM_FAULT_MAJOR)
1191 tsk->maj_flt++;
1192 else
1193 tsk->min_flt++;
1194
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001195 /*
Nick Piggin83c54072007-07-19 01:47:05 -07001196 * The VM_FAULT_WRITE bit tells us that
1197 * do_wp_page has broken COW when necessary,
1198 * even if maybe_mkwrite decided not to set
1199 * pte_write. We can thus safely do subsequent
1200 * page lookups as if they were reads.
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001201 */
1202 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001203 foll_flags &= ~FOLL_WRITE;
Nick Piggin83c54072007-07-19 01:47:05 -07001204
Benjamin Herrenschmidt7f7bbbe2006-10-06 00:43:53 -07001205 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001206 }
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001207 if (IS_ERR(page))
1208 return i ? i : PTR_ERR(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001210 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001211
Russell Kinga6f36be2006-12-30 22:24:19 +00001212 flush_anon_page(vma, page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001213 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001214 }
1215 if (vmas)
1216 vmas[i] = vma;
1217 i++;
1218 start += PAGE_SIZE;
1219 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001220 } while (len && start < vma->vm_end);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001221 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 return i;
1223}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001224EXPORT_SYMBOL(get_user_pages);
1225
Harvey Harrison920c7a52008-02-04 22:29:26 -08001226pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1227 spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001228{
1229 pgd_t * pgd = pgd_offset(mm, addr);
1230 pud_t * pud = pud_alloc(mm, pgd, addr);
1231 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001232 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001233 if (pmd)
1234 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1235 }
1236 return NULL;
1237}
1238
Linus Torvalds1da177e2005-04-16 15:20:36 -07001239/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001240 * This is the old fallback for page remapping.
1241 *
1242 * For historical reasons, it only allows reserved pages. Only
1243 * old drivers should use this, and they needed to mark their
1244 * pages reserved for the old functions anyway.
1245 */
Nick Piggin423bad602008-04-28 02:13:01 -07001246static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1247 struct page *page, pgprot_t prot)
Linus Torvalds238f58d2005-11-29 13:01:56 -08001248{
Nick Piggin423bad602008-04-28 02:13:01 -07001249 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001250 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001251 pte_t *pte;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001252 spinlock_t *ptl;
1253
Balbir Singhe1a1cd52008-02-07 00:14:02 -08001254 retval = mem_cgroup_charge(page, mm, GFP_KERNEL);
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001255 if (retval)
1256 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001257
1258 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001259 if (PageAnon(page))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001260 goto out_uncharge;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001261 retval = -ENOMEM;
1262 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001263 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001264 if (!pte)
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001265 goto out_uncharge;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001266 retval = -EBUSY;
1267 if (!pte_none(*pte))
1268 goto out_unlock;
1269
1270 /* Ok, finally just insert the thing.. */
1271 get_page(page);
1272 inc_mm_counter(mm, file_rss);
1273 page_add_file_rmap(page);
1274 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1275
1276 retval = 0;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001277 pte_unmap_unlock(pte, ptl);
1278 return retval;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001279out_unlock:
1280 pte_unmap_unlock(pte, ptl);
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001281out_uncharge:
1282 mem_cgroup_uncharge_page(page);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001283out:
1284 return retval;
1285}
1286
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001287/**
1288 * vm_insert_page - insert single page into user vma
1289 * @vma: user vma to map to
1290 * @addr: target user address of this page
1291 * @page: source kernel page
1292 *
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001293 * This allows drivers to insert individual pages they've allocated
1294 * into a user vma.
1295 *
1296 * The page has to be a nice clean _individual_ kernel allocation.
1297 * If you allocate a compound page, you need to have marked it as
1298 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001299 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001300 *
1301 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1302 * took an arbitrary page protection parameter. This doesn't allow
1303 * that. Your vma protection will have to be set up correctly, which
1304 * means that if you want a shared writable mapping, you'd better
1305 * ask for a shared writable mapping!
1306 *
1307 * The page does not need to be reserved.
1308 */
Nick Piggin423bad602008-04-28 02:13:01 -07001309int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1310 struct page *page)
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001311{
1312 if (addr < vma->vm_start || addr >= vma->vm_end)
1313 return -EFAULT;
1314 if (!page_count(page))
1315 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001316 vma->vm_flags |= VM_INSERTPAGE;
Nick Piggin423bad602008-04-28 02:13:01 -07001317 return insert_page(vma, addr, page, vma->vm_page_prot);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001318}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001319EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001320
Nick Piggin423bad602008-04-28 02:13:01 -07001321static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1322 unsigned long pfn, pgprot_t prot)
1323{
1324 struct mm_struct *mm = vma->vm_mm;
1325 int retval;
1326 pte_t *pte, entry;
1327 spinlock_t *ptl;
1328
1329 retval = -ENOMEM;
1330 pte = get_locked_pte(mm, addr, &ptl);
1331 if (!pte)
1332 goto out;
1333 retval = -EBUSY;
1334 if (!pte_none(*pte))
1335 goto out_unlock;
1336
1337 /* Ok, finally just insert the thing.. */
1338 entry = pte_mkspecial(pfn_pte(pfn, prot));
1339 set_pte_at(mm, addr, pte, entry);
1340 update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
1341
1342 retval = 0;
1343out_unlock:
1344 pte_unmap_unlock(pte, ptl);
1345out:
1346 return retval;
1347}
1348
Nick Piggine0dc0d82007-02-12 00:51:36 -08001349/**
1350 * vm_insert_pfn - insert single pfn into user vma
1351 * @vma: user vma to map to
1352 * @addr: target user address of this page
1353 * @pfn: source kernel pfn
1354 *
1355 * Similar to vm_inert_page, this allows drivers to insert individual pages
1356 * they've allocated into a user vma. Same comments apply.
1357 *
1358 * This function should only be called from a vm_ops->fault handler, and
1359 * in that case the handler should return NULL.
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001360 *
1361 * vma cannot be a COW mapping.
1362 *
1363 * As this is called only for pages that do not currently exist, we
1364 * do not need to flush old virtual caches or the TLB.
Nick Piggine0dc0d82007-02-12 00:51:36 -08001365 */
1366int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
Nick Piggin423bad602008-04-28 02:13:01 -07001367 unsigned long pfn)
Nick Piggine0dc0d82007-02-12 00:51:36 -08001368{
Nick Piggin7e675132008-04-28 02:13:00 -07001369 /*
1370 * Technically, architectures with pte_special can avoid all these
1371 * restrictions (same for remap_pfn_range). However we would like
1372 * consistency in testing and feature parity among all, so we should
1373 * try to keep these invariants in place for everybody.
1374 */
Jared Hulbertb379d792008-04-28 02:12:58 -07001375 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1376 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1377 (VM_PFNMAP|VM_MIXEDMAP));
1378 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1379 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
Nick Piggine0dc0d82007-02-12 00:51:36 -08001380
Nick Piggin423bad602008-04-28 02:13:01 -07001381 if (addr < vma->vm_start || addr >= vma->vm_end)
1382 return -EFAULT;
1383 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
Nick Piggine0dc0d82007-02-12 00:51:36 -08001384}
1385EXPORT_SYMBOL(vm_insert_pfn);
1386
Nick Piggin423bad602008-04-28 02:13:01 -07001387int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1388 unsigned long pfn)
1389{
1390 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1391
1392 if (addr < vma->vm_start || addr >= vma->vm_end)
1393 return -EFAULT;
1394
1395 /*
1396 * If we don't have pte special, then we have to use the pfn_valid()
1397 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1398 * refcount the page if pfn_valid is true (hence insert_page rather
1399 * than insert_pfn).
1400 */
1401 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1402 struct page *page;
1403
1404 page = pfn_to_page(pfn);
1405 return insert_page(vma, addr, page, vma->vm_page_prot);
1406 }
1407 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1408}
1409EXPORT_SYMBOL(vm_insert_mixed);
1410
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001411/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001412 * maps a range of physical memory into the requested pages. the old
1413 * mappings are removed. any references to nonexistent pages results
1414 * in null mappings (currently treated as "copy-on-access")
1415 */
1416static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1417 unsigned long addr, unsigned long end,
1418 unsigned long pfn, pgprot_t prot)
1419{
1420 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001421 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422
Hugh Dickinsc74df322005-10-29 18:16:23 -07001423 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001424 if (!pte)
1425 return -ENOMEM;
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001426 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427 do {
1428 BUG_ON(!pte_none(*pte));
Nick Piggin7e675132008-04-28 02:13:00 -07001429 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001430 pfn++;
1431 } while (pte++, addr += PAGE_SIZE, addr != end);
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001432 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -07001433 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001434 return 0;
1435}
1436
1437static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1438 unsigned long addr, unsigned long end,
1439 unsigned long pfn, pgprot_t prot)
1440{
1441 pmd_t *pmd;
1442 unsigned long next;
1443
1444 pfn -= addr >> PAGE_SHIFT;
1445 pmd = pmd_alloc(mm, pud, addr);
1446 if (!pmd)
1447 return -ENOMEM;
1448 do {
1449 next = pmd_addr_end(addr, end);
1450 if (remap_pte_range(mm, pmd, addr, next,
1451 pfn + (addr >> PAGE_SHIFT), prot))
1452 return -ENOMEM;
1453 } while (pmd++, addr = next, addr != end);
1454 return 0;
1455}
1456
1457static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1458 unsigned long addr, unsigned long end,
1459 unsigned long pfn, pgprot_t prot)
1460{
1461 pud_t *pud;
1462 unsigned long next;
1463
1464 pfn -= addr >> PAGE_SHIFT;
1465 pud = pud_alloc(mm, pgd, addr);
1466 if (!pud)
1467 return -ENOMEM;
1468 do {
1469 next = pud_addr_end(addr, end);
1470 if (remap_pmd_range(mm, pud, addr, next,
1471 pfn + (addr >> PAGE_SHIFT), prot))
1472 return -ENOMEM;
1473 } while (pud++, addr = next, addr != end);
1474 return 0;
1475}
1476
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001477/**
1478 * remap_pfn_range - remap kernel memory to userspace
1479 * @vma: user vma to map to
1480 * @addr: target user address to start at
1481 * @pfn: physical address of kernel memory
1482 * @size: size of map area
1483 * @prot: page protection flags for this mapping
1484 *
1485 * Note: this is only safe if the mm semaphore is held when called.
1486 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001487int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1488 unsigned long pfn, unsigned long size, pgprot_t prot)
1489{
1490 pgd_t *pgd;
1491 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001492 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001493 struct mm_struct *mm = vma->vm_mm;
1494 int err;
1495
1496 /*
1497 * Physically remapped pages are special. Tell the
1498 * rest of the world about it:
1499 * VM_IO tells people not to look at these pages
1500 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001501 * VM_RESERVED is specified all over the place, because
1502 * in 2.4 it kept swapout's vma scan off this vma; but
1503 * in 2.6 the LRU scan won't even find its pages, so this
1504 * flag means no more than count its pages in reserved_vm,
1505 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001506 * VM_PFNMAP tells the core MM that the base pages are just
1507 * raw PFN mappings, and do not have a "struct page" associated
1508 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001509 *
1510 * There's a horrible special case to handle copy-on-write
1511 * behaviour that some programs depend on. We mark the "original"
1512 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001513 */
Linus Torvalds67121172005-12-11 20:38:17 -08001514 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001515 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001516 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001517 vma->vm_pgoff = pfn;
1518 }
1519
Linus Torvalds6aab3412005-11-28 14:34:23 -08001520 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001521
1522 BUG_ON(addr >= end);
1523 pfn -= addr >> PAGE_SHIFT;
1524 pgd = pgd_offset(mm, addr);
1525 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001526 do {
1527 next = pgd_addr_end(addr, end);
1528 err = remap_pud_range(mm, pgd, addr, next,
1529 pfn + (addr >> PAGE_SHIFT), prot);
1530 if (err)
1531 break;
1532 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001533 return err;
1534}
1535EXPORT_SYMBOL(remap_pfn_range);
1536
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001537static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1538 unsigned long addr, unsigned long end,
1539 pte_fn_t fn, void *data)
1540{
1541 pte_t *pte;
1542 int err;
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001543 pgtable_t token;
Borislav Petkov94909912007-05-06 14:49:17 -07001544 spinlock_t *uninitialized_var(ptl);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001545
1546 pte = (mm == &init_mm) ?
1547 pte_alloc_kernel(pmd, addr) :
1548 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1549 if (!pte)
1550 return -ENOMEM;
1551
1552 BUG_ON(pmd_huge(*pmd));
1553
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001554 token = pmd_pgtable(*pmd);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001555
1556 do {
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001557 err = fn(pte, token, addr, data);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001558 if (err)
1559 break;
1560 } while (pte++, addr += PAGE_SIZE, addr != end);
1561
1562 if (mm != &init_mm)
1563 pte_unmap_unlock(pte-1, ptl);
1564 return err;
1565}
1566
1567static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1568 unsigned long addr, unsigned long end,
1569 pte_fn_t fn, void *data)
1570{
1571 pmd_t *pmd;
1572 unsigned long next;
1573 int err;
1574
Andi Kleenceb86872008-07-23 21:27:50 -07001575 BUG_ON(pud_huge(*pud));
1576
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001577 pmd = pmd_alloc(mm, pud, addr);
1578 if (!pmd)
1579 return -ENOMEM;
1580 do {
1581 next = pmd_addr_end(addr, end);
1582 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1583 if (err)
1584 break;
1585 } while (pmd++, addr = next, addr != end);
1586 return err;
1587}
1588
1589static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1590 unsigned long addr, unsigned long end,
1591 pte_fn_t fn, void *data)
1592{
1593 pud_t *pud;
1594 unsigned long next;
1595 int err;
1596
1597 pud = pud_alloc(mm, pgd, addr);
1598 if (!pud)
1599 return -ENOMEM;
1600 do {
1601 next = pud_addr_end(addr, end);
1602 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1603 if (err)
1604 break;
1605 } while (pud++, addr = next, addr != end);
1606 return err;
1607}
1608
1609/*
1610 * Scan a region of virtual memory, filling in page tables as necessary
1611 * and calling a provided function on each leaf page table.
1612 */
1613int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1614 unsigned long size, pte_fn_t fn, void *data)
1615{
1616 pgd_t *pgd;
1617 unsigned long next;
1618 unsigned long end = addr + size;
1619 int err;
1620
1621 BUG_ON(addr >= end);
1622 pgd = pgd_offset(mm, addr);
1623 do {
1624 next = pgd_addr_end(addr, end);
1625 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
1626 if (err)
1627 break;
1628 } while (pgd++, addr = next, addr != end);
1629 return err;
1630}
1631EXPORT_SYMBOL_GPL(apply_to_page_range);
1632
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001634 * handle_pte_fault chooses page fault handler according to an entry
1635 * which was read non-atomically. Before making any commitment, on
1636 * those architectures or configurations (e.g. i386 with PAE) which
1637 * might give a mix of unmatched parts, do_swap_page and do_file_page
1638 * must check under lock before unmapping the pte and proceeding
1639 * (but do_wp_page is only called after already making such a check;
1640 * and do_anonymous_page and do_no_page can safely check later on).
1641 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001642static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001643 pte_t *page_table, pte_t orig_pte)
1644{
1645 int same = 1;
1646#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1647 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001648 spinlock_t *ptl = pte_lockptr(mm, pmd);
1649 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001650 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001651 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001652 }
1653#endif
1654 pte_unmap(page_table);
1655 return same;
1656}
1657
1658/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001659 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1660 * servicing faults for write access. In the normal case, do always want
1661 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1662 * that do not have writing enabled, when used by access_process_vm.
1663 */
1664static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1665{
1666 if (likely(vma->vm_flags & VM_WRITE))
1667 pte = pte_mkwrite(pte);
1668 return pte;
1669}
1670
Atsushi Nemoto9de455b2006-12-12 17:14:55 +00001671static 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 -08001672{
1673 /*
1674 * If the source page was a PFN mapping, we don't have
1675 * a "struct page" for it. We do a best-effort copy by
1676 * just copying from the original user address. If that
1677 * fails, we just zero-fill it. Live with it.
1678 */
1679 if (unlikely(!src)) {
1680 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2dbbc2005-11-29 14:07:55 -08001681 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1682
1683 /*
1684 * This really shouldn't fail, because the page is there
1685 * in the page tables. But it might just be unreadable,
1686 * in which case we just give up and fill the result with
1687 * zeroes.
1688 */
1689 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001690 memset(kaddr, 0, PAGE_SIZE);
1691 kunmap_atomic(kaddr, KM_USER0);
Dmitriy Monakhovc4ec7b02006-10-19 23:29:08 -07001692 flush_dcache_page(dst);
Nick Piggin0ed361d2008-02-04 22:29:34 -08001693 } else
1694 copy_user_highpage(dst, src, va, vma);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001695}
1696
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698 * This routine handles present pages, when users try to write
1699 * to a shared page. It is done by copying the page to a new address
1700 * and decrementing the shared-page counter for the old page.
1701 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 * Note that this routine assumes that the protection checks have been
1703 * done by the caller (the low-level page fault routine in most cases).
1704 * Thus we can safely just mark it writable once we've done any necessary
1705 * COW.
1706 *
1707 * We also mark the page dirty at this point even though the page will
1708 * change only once the write actually happens. This avoids a few races,
1709 * and potentially makes it more efficient.
1710 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001711 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1712 * but allow concurrent faults), with pte both mapped and locked.
1713 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001715static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1716 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001717 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001718{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001719 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001720 pte_t entry;
Nick Piggin83c54072007-07-19 01:47:05 -07001721 int reuse = 0, ret = 0;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02001722 int page_mkwrite = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001723 struct page *dirty_page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724
Linus Torvalds6aab3412005-11-28 14:34:23 -08001725 old_page = vm_normal_page(vma, address, orig_pte);
Peter Zijlstra251b97f2008-07-04 09:59:24 -07001726 if (!old_page) {
1727 /*
1728 * VM_MIXEDMAP !pfn_valid() case
1729 *
1730 * We should not cow pages in a shared writeable mapping.
1731 * Just mark the pages writable as we can't do any dirty
1732 * accounting on raw pfn maps.
1733 */
1734 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
1735 (VM_WRITE|VM_SHARED))
1736 goto reuse;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001737 goto gotten;
Peter Zijlstra251b97f2008-07-04 09:59:24 -07001738 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001740 /*
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001741 * Take out anonymous pages first, anonymous shared vmas are
1742 * not dirty accountable.
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001743 */
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001744 if (PageAnon(old_page)) {
1745 if (!TestSetPageLocked(old_page)) {
1746 reuse = can_share_swap_page(old_page);
1747 unlock_page(old_page);
1748 }
1749 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001750 (VM_WRITE|VM_SHARED))) {
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001751 /*
1752 * Only catch write-faults on shared writable pages,
1753 * read-only shared pages can get COWed by
1754 * get_user_pages(.write=1, .force=1).
1755 */
David Howells9637a5e2006-06-23 02:03:43 -07001756 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
1757 /*
1758 * Notify the address space that the page is about to
1759 * become writable so that it can prohibit this or wait
1760 * for the page to get into an appropriate state.
1761 *
1762 * We do this without the lock held, so that it can
1763 * sleep if it needs to.
1764 */
1765 page_cache_get(old_page);
1766 pte_unmap_unlock(page_table, ptl);
1767
1768 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
1769 goto unwritable_page;
1770
David Howells9637a5e2006-06-23 02:03:43 -07001771 /*
1772 * Since we dropped the lock we need to revalidate
1773 * the PTE as someone else may have changed it. If
1774 * they did, we just return, as we can count on the
1775 * MMU to tell us if they didn't also make it writable.
1776 */
1777 page_table = pte_offset_map_lock(mm, pmd, address,
1778 &ptl);
Hugh Dickinsc3704ce2007-02-10 01:43:00 -08001779 page_cache_release(old_page);
David Howells9637a5e2006-06-23 02:03:43 -07001780 if (!pte_same(*page_table, orig_pte))
1781 goto unlock;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02001782
1783 page_mkwrite = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001784 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001785 dirty_page = old_page;
1786 get_page(dirty_page);
David Howells9637a5e2006-06-23 02:03:43 -07001787 reuse = 1;
David Howells9637a5e2006-06-23 02:03:43 -07001788 }
1789
1790 if (reuse) {
Peter Zijlstra251b97f2008-07-04 09:59:24 -07001791reuse:
David Howells9637a5e2006-06-23 02:03:43 -07001792 flush_cache_page(vma, address, pte_pfn(orig_pte));
1793 entry = pte_mkyoung(orig_pte);
1794 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
KAMEZAWA Hiroyuki954ffcb2007-10-16 01:25:44 -07001795 if (ptep_set_access_flags(vma, address, page_table, entry,1))
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07001796 update_mmu_cache(vma, address, entry);
David Howells9637a5e2006-06-23 02:03:43 -07001797 ret |= VM_FAULT_WRITE;
1798 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001799 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001800
1801 /*
1802 * Ok, we need to copy. Oh, well..
1803 */
Nick Pigginb5810032005-10-29 18:16:12 -07001804 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001805gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001806 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001807
1808 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001809 goto oom;
Nick Piggin557ed1f2007-10-16 01:24:40 -07001810 VM_BUG_ON(old_page == ZERO_PAGE(0));
1811 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1812 if (!new_page)
1813 goto oom;
1814 cow_user_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08001815 __SetPageUptodate(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001816
Balbir Singhe1a1cd52008-02-07 00:14:02 -08001817 if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001818 goto oom_free_new;
1819
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 /*
1821 * Re-check the pte - we dropped the lock
1822 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001823 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001824 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001825 if (old_page) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001826 if (!PageAnon(old_page)) {
1827 dec_mm_counter(mm, file_rss);
1828 inc_mm_counter(mm, anon_rss);
1829 }
1830 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001831 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001832 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001833 entry = mk_pte(new_page, vma->vm_page_prot);
1834 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Siddha, Suresh B4ce072f2006-09-29 01:58:42 -07001835 /*
1836 * Clear the pte entry and flush it first, before updating the
1837 * pte with the new entry. This will avoid a race condition
1838 * seen in the presence of one thread doing SMC and another
1839 * thread doing COW.
1840 */
1841 ptep_clear_flush(vma, address, page_table);
1842 set_pte_at(mm, address, page_table, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001843 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08001845 page_add_new_anon_rmap(new_page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001846
Nick Piggin945754a2008-06-23 14:30:30 +02001847 if (old_page) {
1848 /*
1849 * Only after switching the pte to the new page may
1850 * we remove the mapcount here. Otherwise another
1851 * process may come and find the rmap count decremented
1852 * before the pte is switched to the new page, and
1853 * "reuse" the old page writing into it while our pte
1854 * here still points into it and can be read by other
1855 * threads.
1856 *
1857 * The critical issue is to order this
1858 * page_remove_rmap with the ptp_clear_flush above.
1859 * Those stores are ordered by (if nothing else,)
1860 * the barrier present in the atomic_add_negative
1861 * in page_remove_rmap.
1862 *
1863 * Then the TLB flush in ptep_clear_flush ensures that
1864 * no process can access the old page before the
1865 * decremented mapcount is visible. And the old page
1866 * cannot be reused until after the decremented
1867 * mapcount is visible. So transitively, TLBs to
1868 * old page will be flushed before it can be reused.
1869 */
1870 page_remove_rmap(old_page, vma);
1871 }
1872
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 /* Free the old page.. */
1874 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001875 ret |= VM_FAULT_WRITE;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001876 } else
1877 mem_cgroup_uncharge_page(new_page);
1878
Hugh Dickins920fc352005-11-21 21:32:17 -08001879 if (new_page)
1880 page_cache_release(new_page);
1881 if (old_page)
1882 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001883unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001884 pte_unmap_unlock(page_table, ptl);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001885 if (dirty_page) {
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03001886 if (vma->vm_file)
1887 file_update_time(vma->vm_file);
1888
Nick Piggin79352892007-07-19 01:47:22 -07001889 /*
1890 * Yes, Virginia, this is actually required to prevent a race
1891 * with clear_page_dirty_for_io() from clearing the page dirty
1892 * bit after it clear all dirty ptes, but before a racing
1893 * do_wp_page installs a dirty pte.
1894 *
1895 * do_no_page is protected similarly.
1896 */
1897 wait_on_page_locked(dirty_page);
Peter Zijlstraa200ee12007-10-08 18:54:37 +02001898 set_page_dirty_balance(dirty_page, page_mkwrite);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001899 put_page(dirty_page);
1900 }
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001901 return ret;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001902oom_free_new:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08001903 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001904oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001905 if (old_page)
1906 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001907 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07001908
1909unwritable_page:
1910 page_cache_release(old_page);
1911 return VM_FAULT_SIGBUS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001912}
1913
1914/*
1915 * Helper functions for unmap_mapping_range().
1916 *
1917 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1918 *
1919 * We have to restart searching the prio_tree whenever we drop the lock,
1920 * since the iterator is only valid while the lock is held, and anyway
1921 * a later vma might be split and reinserted earlier while lock dropped.
1922 *
1923 * The list of nonlinear vmas could be handled more efficiently, using
1924 * a placeholder, but handle it in the same way until a need is shown.
1925 * It is important to search the prio_tree before nonlinear list: a vma
1926 * may become nonlinear and be shifted from prio_tree to nonlinear list
1927 * while the lock is dropped; but never shifted from list to prio_tree.
1928 *
1929 * In order to make forward progress despite restarting the search,
1930 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1931 * quickly skip it next time around. Since the prio_tree search only
1932 * shows us those vmas affected by unmapping the range in question, we
1933 * can't efficiently keep all vmas in step with mapping->truncate_count:
1934 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1935 * mapping->truncate_count and vma->vm_truncate_count are protected by
1936 * i_mmap_lock.
1937 *
1938 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001939 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940 * and restart from that address when we reach that vma again. It might
1941 * have been split or merged, shrunk or extended, but never shifted: so
1942 * restart_addr remains valid so long as it remains in the vma's range.
1943 * unmap_mapping_range forces truncate_count to leap over page-aligned
1944 * values so we can save vma's restart_addr in its truncate_count field.
1945 */
1946#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1947
1948static void reset_vma_truncate_counts(struct address_space *mapping)
1949{
1950 struct vm_area_struct *vma;
1951 struct prio_tree_iter iter;
1952
1953 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1954 vma->vm_truncate_count = 0;
1955 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1956 vma->vm_truncate_count = 0;
1957}
1958
1959static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1960 unsigned long start_addr, unsigned long end_addr,
1961 struct zap_details *details)
1962{
1963 unsigned long restart_addr;
1964 int need_break;
1965
Nick Piggind00806b2007-07-19 01:46:57 -07001966 /*
1967 * files that support invalidating or truncating portions of the
Nick Piggind0217ac2007-07-19 01:47:03 -07001968 * file from under mmaped areas must have their ->fault function
Nick Piggin83c54072007-07-19 01:47:05 -07001969 * return a locked page (and set VM_FAULT_LOCKED in the return).
1970 * This provides synchronisation against concurrent unmapping here.
Nick Piggind00806b2007-07-19 01:46:57 -07001971 */
Nick Piggind00806b2007-07-19 01:46:57 -07001972
Linus Torvalds1da177e2005-04-16 15:20:36 -07001973again:
1974 restart_addr = vma->vm_truncate_count;
1975 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1976 start_addr = restart_addr;
1977 if (start_addr >= end_addr) {
1978 /* Top of vma has been split off since last time */
1979 vma->vm_truncate_count = details->truncate_count;
1980 return 0;
1981 }
1982 }
1983
Hugh Dickinsee39b372005-04-19 13:29:15 -07001984 restart_addr = zap_page_range(vma, start_addr,
1985 end_addr - start_addr, details);
Nick Piggin95c354f2008-01-30 13:31:20 +01001986 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987
Hugh Dickinsee39b372005-04-19 13:29:15 -07001988 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001989 /* We have now completed this vma: mark it so */
1990 vma->vm_truncate_count = details->truncate_count;
1991 if (!need_break)
1992 return 0;
1993 } else {
1994 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001995 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001996 if (!need_break)
1997 goto again;
1998 }
1999
2000 spin_unlock(details->i_mmap_lock);
2001 cond_resched();
2002 spin_lock(details->i_mmap_lock);
2003 return -EINTR;
2004}
2005
2006static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2007 struct zap_details *details)
2008{
2009 struct vm_area_struct *vma;
2010 struct prio_tree_iter iter;
2011 pgoff_t vba, vea, zba, zea;
2012
2013restart:
2014 vma_prio_tree_foreach(vma, &iter, root,
2015 details->first_index, details->last_index) {
2016 /* Skip quickly over those we have already dealt with */
2017 if (vma->vm_truncate_count == details->truncate_count)
2018 continue;
2019
2020 vba = vma->vm_pgoff;
2021 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2022 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2023 zba = details->first_index;
2024 if (zba < vba)
2025 zba = vba;
2026 zea = details->last_index;
2027 if (zea > vea)
2028 zea = vea;
2029
2030 if (unmap_mapping_range_vma(vma,
2031 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2032 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2033 details) < 0)
2034 goto restart;
2035 }
2036}
2037
2038static inline void unmap_mapping_range_list(struct list_head *head,
2039 struct zap_details *details)
2040{
2041 struct vm_area_struct *vma;
2042
2043 /*
2044 * In nonlinear VMAs there is no correspondence between virtual address
2045 * offset and file offset. So we must perform an exhaustive search
2046 * across *all* the pages in each nonlinear VMA, not just the pages
2047 * whose virtual address lies outside the file truncation point.
2048 */
2049restart:
2050 list_for_each_entry(vma, head, shared.vm_set.list) {
2051 /* Skip quickly over those we have already dealt with */
2052 if (vma->vm_truncate_count == details->truncate_count)
2053 continue;
2054 details->nonlinear_vma = vma;
2055 if (unmap_mapping_range_vma(vma, vma->vm_start,
2056 vma->vm_end, details) < 0)
2057 goto restart;
2058 }
2059}
2060
2061/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08002062 * 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 -07002063 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002064 * @holebegin: byte in first page to unmap, relative to the start of
2065 * the underlying file. This will be rounded down to a PAGE_SIZE
2066 * boundary. Note that this is different from vmtruncate(), which
2067 * must keep the partial page. In contrast, we must get rid of
2068 * partial pages.
2069 * @holelen: size of prospective hole in bytes. This will be rounded
2070 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2071 * end of the file.
2072 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2073 * but 0 when invalidating pagecache, don't throw away private data.
2074 */
2075void unmap_mapping_range(struct address_space *mapping,
2076 loff_t const holebegin, loff_t const holelen, int even_cows)
2077{
2078 struct zap_details details;
2079 pgoff_t hba = holebegin >> PAGE_SHIFT;
2080 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2081
2082 /* Check for overflow. */
2083 if (sizeof(holelen) > sizeof(hlen)) {
2084 long long holeend =
2085 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2086 if (holeend & ~(long long)ULONG_MAX)
2087 hlen = ULONG_MAX - hba + 1;
2088 }
2089
2090 details.check_mapping = even_cows? NULL: mapping;
2091 details.nonlinear_vma = NULL;
2092 details.first_index = hba;
2093 details.last_index = hba + hlen - 1;
2094 if (details.last_index < details.first_index)
2095 details.last_index = ULONG_MAX;
2096 details.i_mmap_lock = &mapping->i_mmap_lock;
2097
2098 spin_lock(&mapping->i_mmap_lock);
2099
Nick Piggind00806b2007-07-19 01:46:57 -07002100 /* Protect against endless unmapping loops */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002101 mapping->truncate_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2103 if (mapping->truncate_count == 0)
2104 reset_vma_truncate_counts(mapping);
2105 mapping->truncate_count++;
2106 }
2107 details.truncate_count = mapping->truncate_count;
2108
2109 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2110 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2111 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2112 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2113 spin_unlock(&mapping->i_mmap_lock);
2114}
2115EXPORT_SYMBOL(unmap_mapping_range);
2116
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07002117/**
2118 * vmtruncate - unmap mappings "freed" by truncate() syscall
2119 * @inode: inode of the file used
2120 * @offset: file offset to start truncating
Linus Torvalds1da177e2005-04-16 15:20:36 -07002121 *
2122 * NOTE! We have to be ready to update the memory sharing
2123 * between the file and the memory map for a potential last
2124 * incomplete page. Ugly, but necessary.
2125 */
2126int vmtruncate(struct inode * inode, loff_t offset)
2127{
Christoph Hellwig61d50482008-02-04 22:28:56 -08002128 if (inode->i_size < offset) {
2129 unsigned long limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002130
Christoph Hellwig61d50482008-02-04 22:28:56 -08002131 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
2132 if (limit != RLIM_INFINITY && offset > limit)
2133 goto out_sig;
2134 if (offset > inode->i_sb->s_maxbytes)
2135 goto out_big;
2136 i_size_write(inode, offset);
2137 } else {
2138 struct address_space *mapping = inode->i_mapping;
Nick Piggind00806b2007-07-19 01:46:57 -07002139
Christoph Hellwig61d50482008-02-04 22:28:56 -08002140 /*
2141 * truncation of in-use swapfiles is disallowed - it would
2142 * cause subsequent swapout to scribble on the now-freed
2143 * blocks.
2144 */
2145 if (IS_SWAPFILE(inode))
2146 return -ETXTBSY;
2147 i_size_write(inode, offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148
Christoph Hellwig61d50482008-02-04 22:28:56 -08002149 /*
2150 * unmap_mapping_range is called twice, first simply for
2151 * efficiency so that truncate_inode_pages does fewer
2152 * single-page unmaps. However after this first call, and
2153 * before truncate_inode_pages finishes, it is possible for
2154 * private pages to be COWed, which remain after
2155 * truncate_inode_pages finishes, hence the second
2156 * unmap_mapping_range call must be made for correctness.
2157 */
2158 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2159 truncate_inode_pages(mapping, offset);
2160 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2161 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002162
Linus Torvalds1da177e2005-04-16 15:20:36 -07002163 if (inode->i_op && inode->i_op->truncate)
2164 inode->i_op->truncate(inode);
2165 return 0;
Christoph Hellwig61d50482008-02-04 22:28:56 -08002166
Linus Torvalds1da177e2005-04-16 15:20:36 -07002167out_sig:
2168 send_sig(SIGXFSZ, current, 0);
2169out_big:
2170 return -EFBIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002172EXPORT_SYMBOL(vmtruncate);
2173
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002174int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2175{
2176 struct address_space *mapping = inode->i_mapping;
2177
2178 /*
2179 * If the underlying filesystem is not going to provide
2180 * a way to truncate a range of blocks (punch a hole) -
2181 * we should return failure right now.
2182 */
2183 if (!inode->i_op || !inode->i_op->truncate_range)
2184 return -ENOSYS;
2185
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002186 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002187 down_write(&inode->i_alloc_sem);
2188 unmap_mapping_range(mapping, offset, (end - offset), 1);
2189 truncate_inode_pages_range(mapping, offset, end);
Nick Piggind00806b2007-07-19 01:46:57 -07002190 unmap_mapping_range(mapping, offset, (end - offset), 1);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002191 inode->i_op->truncate_range(inode, offset, end);
2192 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002193 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002194
2195 return 0;
2196}
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002197
Linus Torvalds1da177e2005-04-16 15:20:36 -07002198/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002199 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2200 * but allow concurrent faults), and pte mapped but not yet locked.
2201 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002202 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002203static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2204 unsigned long address, pte_t *page_table, pmd_t *pmd,
2205 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002206{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002207 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002208 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07002209 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 pte_t pte;
Nick Piggin83c54072007-07-19 01:47:05 -07002211 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002212
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002213 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002214 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07002215
2216 entry = pte_to_swp_entry(orig_pte);
Christoph Lameter06972122006-06-23 02:03:35 -07002217 if (is_migration_entry(entry)) {
2218 migration_entry_wait(mm, pmd, address);
2219 goto out;
2220 }
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002221 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002222 page = lookup_swap_cache(entry);
2223 if (!page) {
Ashwin Chaugule098fe652006-12-06 20:31:54 -08002224 grab_swap_token(); /* Contend for token _before_ read-in */
Hugh Dickins02098fe2008-02-04 22:28:42 -08002225 page = swapin_readahead(entry,
2226 GFP_HIGHUSER_MOVABLE, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002227 if (!page) {
2228 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002229 * Back out if somebody else faulted in this pte
2230 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002232 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002233 if (likely(pte_same(*page_table, orig_pte)))
2234 ret = VM_FAULT_OOM;
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002235 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Hugh Dickins65500d22005-10-29 18:15:59 -07002236 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002237 }
2238
2239 /* Had to read the page from swap area: Major fault */
2240 ret = VM_FAULT_MAJOR;
Christoph Lameterf8891e52006-06-30 01:55:45 -07002241 count_vm_event(PGMAJFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002242 }
2243
Balbir Singhe1a1cd52008-02-07 00:14:02 -08002244 if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002245 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2246 ret = VM_FAULT_OOM;
2247 goto out;
2248 }
2249
Linus Torvalds1da177e2005-04-16 15:20:36 -07002250 mark_page_accessed(page);
2251 lock_page(page);
Balbir Singh20a10222007-11-14 17:00:33 -08002252 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253
2254 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002255 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002256 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002257 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07002258 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07002259 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002260
2261 if (unlikely(!PageUptodate(page))) {
2262 ret = VM_FAULT_SIGBUS;
2263 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002264 }
2265
2266 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267
Hugh Dickins42946212005-10-29 18:16:05 -07002268 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002269 pte = mk_pte(page, vma->vm_page_prot);
2270 if (write_access && can_share_swap_page(page)) {
2271 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2272 write_access = 0;
2273 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002274
2275 flush_icache_page(vma, page);
2276 set_pte_at(mm, address, page_table, pte);
2277 page_add_anon_rmap(page, vma, address);
2278
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002279 swap_free(entry);
2280 if (vm_swap_full())
2281 remove_exclusive_swap_page(page);
2282 unlock_page(page);
2283
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284 if (write_access) {
Hugh Dickins61469f12008-03-04 14:29:04 -08002285 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2286 if (ret & VM_FAULT_ERROR)
2287 ret &= VM_FAULT_ERROR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002288 goto out;
2289 }
2290
2291 /* No need to invalidate - it was non-present before */
2292 update_mmu_cache(vma, address, pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07002293unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002294 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002295out:
2296 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002297out_nomap:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002298 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002299 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07002300 unlock_page(page);
2301 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002302 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303}
2304
2305/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002306 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2307 * but allow concurrent faults), and pte mapped but not yet locked.
2308 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002309 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002310static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2311 unsigned long address, pte_t *page_table, pmd_t *pmd,
2312 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002313{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002314 struct page *page;
2315 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002317
Nick Piggin557ed1f2007-10-16 01:24:40 -07002318 /* Allocate our own private page. */
2319 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002320
Nick Piggin557ed1f2007-10-16 01:24:40 -07002321 if (unlikely(anon_vma_prepare(vma)))
2322 goto oom;
2323 page = alloc_zeroed_user_highpage_movable(vma, address);
2324 if (!page)
2325 goto oom;
Nick Piggin0ed361d2008-02-04 22:29:34 -08002326 __SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002327
Balbir Singhe1a1cd52008-02-07 00:14:02 -08002328 if (mem_cgroup_charge(page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002329 goto oom_free_page;
2330
Nick Piggin557ed1f2007-10-16 01:24:40 -07002331 entry = mk_pte(page, vma->vm_page_prot);
2332 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002333
Nick Piggin557ed1f2007-10-16 01:24:40 -07002334 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2335 if (!pte_none(*page_table))
2336 goto release;
2337 inc_mm_counter(mm, anon_rss);
2338 lru_cache_add_active(page);
2339 page_add_new_anon_rmap(page, vma, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002340 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002341
2342 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002343 update_mmu_cache(vma, address, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002344unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002345 pte_unmap_unlock(page_table, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002346 return 0;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002347release:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002348 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002349 page_cache_release(page);
2350 goto unlock;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002351oom_free_page:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002352 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002353oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002354 return VM_FAULT_OOM;
2355}
2356
2357/*
Nick Piggin54cb8822007-07-19 01:46:59 -07002358 * __do_fault() tries to create a new page mapping. It aggressively
Linus Torvalds1da177e2005-04-16 15:20:36 -07002359 * tries to share with existing pages, but makes a separate copy if
Nick Piggin54cb8822007-07-19 01:46:59 -07002360 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2361 * the next page fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002362 *
2363 * As this is called only for pages that do not currently exist, we
2364 * do not need to flush old virtual caches or the TLB.
2365 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002366 * We enter with non-exclusive mmap_sem (to exclude vma changes,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002367 * but allow concurrent faults), and pte neither mapped nor locked.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002368 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002369 */
Nick Piggin54cb8822007-07-19 01:46:59 -07002370static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002371 unsigned long address, pmd_t *pmd,
Nick Piggin54cb8822007-07-19 01:46:59 -07002372 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002373{
Hugh Dickins16abfa02007-10-04 16:56:06 +01002374 pte_t *page_table;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002375 spinlock_t *ptl;
Nick Piggind0217ac2007-07-19 01:47:03 -07002376 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002377 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378 int anon = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002379 struct page *dirty_page = NULL;
Nick Piggind0217ac2007-07-19 01:47:03 -07002380 struct vm_fault vmf;
2381 int ret;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002382 int page_mkwrite = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07002383
Nick Piggind0217ac2007-07-19 01:47:03 -07002384 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2385 vmf.pgoff = pgoff;
2386 vmf.flags = flags;
2387 vmf.page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002389 ret = vma->vm_ops->fault(vma, &vmf);
2390 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2391 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002392
Nick Piggind00806b2007-07-19 01:46:57 -07002393 /*
Nick Piggind0217ac2007-07-19 01:47:03 -07002394 * For consistency in subsequent calls, make the faulted page always
Nick Piggind00806b2007-07-19 01:46:57 -07002395 * locked.
2396 */
Nick Piggin83c54072007-07-19 01:47:05 -07002397 if (unlikely(!(ret & VM_FAULT_LOCKED)))
Nick Piggind0217ac2007-07-19 01:47:03 -07002398 lock_page(vmf.page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002399 else
Nick Piggind0217ac2007-07-19 01:47:03 -07002400 VM_BUG_ON(!PageLocked(vmf.page));
Nick Piggind00806b2007-07-19 01:46:57 -07002401
Linus Torvalds1da177e2005-04-16 15:20:36 -07002402 /*
2403 * Should we do an early C-O-W break?
2404 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002405 page = vmf.page;
Nick Piggin54cb8822007-07-19 01:46:59 -07002406 if (flags & FAULT_FLAG_WRITE) {
David Howells9637a5e2006-06-23 02:03:43 -07002407 if (!(vma->vm_flags & VM_SHARED)) {
Nick Piggin54cb8822007-07-19 01:46:59 -07002408 anon = 1;
Nick Piggind00806b2007-07-19 01:46:57 -07002409 if (unlikely(anon_vma_prepare(vma))) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002410 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002411 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002412 }
Nick Piggin83c54072007-07-19 01:47:05 -07002413 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2414 vma, address);
Nick Piggind00806b2007-07-19 01:46:57 -07002415 if (!page) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002416 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002417 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002418 }
Nick Piggind0217ac2007-07-19 01:47:03 -07002419 copy_user_highpage(page, vmf.page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002420 __SetPageUptodate(page);
David Howells9637a5e2006-06-23 02:03:43 -07002421 } else {
Nick Piggin54cb8822007-07-19 01:46:59 -07002422 /*
2423 * If the page will be shareable, see if the backing
David Howells9637a5e2006-06-23 02:03:43 -07002424 * address space wants to know that the page is about
Nick Piggin54cb8822007-07-19 01:46:59 -07002425 * to become writable
2426 */
Mark Fasheh69676142007-07-19 01:47:00 -07002427 if (vma->vm_ops->page_mkwrite) {
2428 unlock_page(page);
2429 if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002430 ret = VM_FAULT_SIGBUS;
2431 anon = 1; /* no anon but release vmf.page */
Mark Fasheh69676142007-07-19 01:47:00 -07002432 goto out_unlocked;
2433 }
2434 lock_page(page);
Nick Piggind0217ac2007-07-19 01:47:03 -07002435 /*
2436 * XXX: this is not quite right (racy vs
2437 * invalidate) to unlock and relock the page
2438 * like this, however a better fix requires
2439 * reworking page_mkwrite locking API, which
2440 * is better done later.
2441 */
2442 if (!page->mapping) {
Nick Piggin83c54072007-07-19 01:47:05 -07002443 ret = 0;
Nick Piggind0217ac2007-07-19 01:47:03 -07002444 anon = 1; /* no anon but release vmf.page */
2445 goto out;
2446 }
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002447 page_mkwrite = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002448 }
2449 }
Nick Piggin54cb8822007-07-19 01:46:59 -07002450
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451 }
2452
Balbir Singhe1a1cd52008-02-07 00:14:02 -08002453 if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002454 ret = VM_FAULT_OOM;
2455 goto out;
2456 }
2457
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002458 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002459
2460 /*
2461 * This silly early PAGE_DIRTY setting removes a race
2462 * due to the bad i386 page protection. But it's valid
2463 * for other architectures too.
2464 *
2465 * Note that if write_access is true, we either now have
2466 * an exclusive copy of the page, or this is a shared mapping,
2467 * so we can make it writable and dirty to avoid having to
2468 * handle that later.
2469 */
2470 /* Only go through if we didn't race with anybody else... */
Nick Piggin54cb8822007-07-19 01:46:59 -07002471 if (likely(pte_same(*page_table, orig_pte))) {
Nick Piggind00806b2007-07-19 01:46:57 -07002472 flush_icache_page(vma, page);
2473 entry = mk_pte(page, vma->vm_page_prot);
Nick Piggin54cb8822007-07-19 01:46:59 -07002474 if (flags & FAULT_FLAG_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002475 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2476 set_pte_at(mm, address, page_table, entry);
2477 if (anon) {
Nick Piggind00806b2007-07-19 01:46:57 -07002478 inc_mm_counter(mm, anon_rss);
2479 lru_cache_add_active(page);
2480 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002481 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002482 inc_mm_counter(mm, file_rss);
Nick Piggind00806b2007-07-19 01:46:57 -07002483 page_add_file_rmap(page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002484 if (flags & FAULT_FLAG_WRITE) {
Nick Piggind00806b2007-07-19 01:46:57 -07002485 dirty_page = page;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002486 get_page(dirty_page);
2487 }
Hugh Dickins42946212005-10-29 18:16:05 -07002488 }
Nick Piggind00806b2007-07-19 01:46:57 -07002489
2490 /* no need to invalidate: a not-present page won't be cached */
2491 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002492 } else {
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002493 mem_cgroup_uncharge_page(page);
Nick Piggind00806b2007-07-19 01:46:57 -07002494 if (anon)
2495 page_cache_release(page);
2496 else
Nick Piggin54cb8822007-07-19 01:46:59 -07002497 anon = 1; /* no anon but release faulted_page */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002498 }
2499
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002500 pte_unmap_unlock(page_table, ptl);
Nick Piggind00806b2007-07-19 01:46:57 -07002501
2502out:
Nick Piggind0217ac2007-07-19 01:47:03 -07002503 unlock_page(vmf.page);
Mark Fasheh69676142007-07-19 01:47:00 -07002504out_unlocked:
Nick Piggind00806b2007-07-19 01:46:57 -07002505 if (anon)
Nick Piggind0217ac2007-07-19 01:47:03 -07002506 page_cache_release(vmf.page);
Nick Piggind00806b2007-07-19 01:46:57 -07002507 else if (dirty_page) {
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03002508 if (vma->vm_file)
2509 file_update_time(vma->vm_file);
2510
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002511 set_page_dirty_balance(dirty_page, page_mkwrite);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002512 put_page(dirty_page);
2513 }
Nick Piggind00806b2007-07-19 01:46:57 -07002514
Nick Piggin83c54072007-07-19 01:47:05 -07002515 return ret;
Nick Piggin54cb8822007-07-19 01:46:59 -07002516}
Nick Piggind00806b2007-07-19 01:46:57 -07002517
Nick Piggin54cb8822007-07-19 01:46:59 -07002518static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2519 unsigned long address, pte_t *page_table, pmd_t *pmd,
2520 int write_access, pte_t orig_pte)
2521{
2522 pgoff_t pgoff = (((address & PAGE_MASK)
Dean Nelson0da7e012007-10-16 01:24:45 -07002523 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
Nick Piggin54cb8822007-07-19 01:46:59 -07002524 unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
2525
Hugh Dickins16abfa02007-10-04 16:56:06 +01002526 pte_unmap(page_table);
2527 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Nick Piggin54cb8822007-07-19 01:46:59 -07002528}
2529
Jes Sorensenf4b81802006-09-27 01:50:10 -07002530/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002531 * Fault of a previously existing named mapping. Repopulate the pte
2532 * from the encoded file_pte if possible. This enables swappable
2533 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002534 *
2535 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2536 * but allow concurrent faults), and pte mapped but not yet locked.
2537 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002538 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002539static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins65500d22005-10-29 18:15:59 -07002540 unsigned long address, pte_t *page_table, pmd_t *pmd,
2541 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002542{
Nick Piggind0217ac2007-07-19 01:47:03 -07002543 unsigned int flags = FAULT_FLAG_NONLINEAR |
2544 (write_access ? FAULT_FLAG_WRITE : 0);
Hugh Dickins65500d22005-10-29 18:15:59 -07002545 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002546
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002547 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Nick Piggin83c54072007-07-19 01:47:05 -07002548 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002549
Nick Piggind0217ac2007-07-19 01:47:03 -07002550 if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
2551 !(vma->vm_flags & VM_CAN_NONLINEAR))) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002552 /*
2553 * Page table corrupted: show pte and kill process.
2554 */
Nick Pigginb5810032005-10-29 18:16:12 -07002555 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002556 return VM_FAULT_OOM;
2557 }
Hugh Dickins65500d22005-10-29 18:15:59 -07002558
2559 pgoff = pte_to_pgoff(orig_pte);
Hugh Dickins16abfa02007-10-04 16:56:06 +01002560 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002561}
2562
2563/*
2564 * These routines also need to handle stuff like marking pages dirty
2565 * and/or accessed for architectures that don't do it in hardware (most
2566 * RISC architectures). The early dirtying is also good on the i386.
2567 *
2568 * There is also a hook called "update_mmu_cache()" that architectures
2569 * with external mmu caches can use to update those (ie the Sparc or
2570 * PowerPC hashed page tables that act as extended TLBs).
2571 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002572 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2573 * but allow concurrent faults), and pte mapped but not yet locked.
2574 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002575 */
2576static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002577 struct vm_area_struct *vma, unsigned long address,
2578 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002579{
2580 pte_t entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002581 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002582
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07002583 entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002584 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002585 if (pte_none(entry)) {
Jes Sorensenf4b81802006-09-27 01:50:10 -07002586 if (vma->vm_ops) {
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002587 if (likely(vma->vm_ops->fault))
Nick Piggin54cb8822007-07-19 01:46:59 -07002588 return do_linear_fault(mm, vma, address,
2589 pte, pmd, write_access, entry);
Jes Sorensenf4b81802006-09-27 01:50:10 -07002590 }
2591 return do_anonymous_page(mm, vma, address,
2592 pte, pmd, write_access);
Hugh Dickins65500d22005-10-29 18:15:59 -07002593 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594 if (pte_file(entry))
Nick Piggind0217ac2007-07-19 01:47:03 -07002595 return do_nonlinear_fault(mm, vma, address,
Hugh Dickins65500d22005-10-29 18:15:59 -07002596 pte, pmd, write_access, entry);
2597 return do_swap_page(mm, vma, address,
2598 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002599 }
2600
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002601 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002602 spin_lock(ptl);
2603 if (unlikely(!pte_same(*pte, entry)))
2604 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002605 if (write_access) {
2606 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002607 return do_wp_page(mm, vma, address,
2608 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002609 entry = pte_mkdirty(entry);
2610 }
2611 entry = pte_mkyoung(entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07002612 if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002613 update_mmu_cache(vma, address, entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002614 } else {
2615 /*
2616 * This is needed only for protection faults but the arch code
2617 * is not yet telling us if this is a protection fault or not.
2618 * This still avoids useless tlb flushes for .text page faults
2619 * with threads.
2620 */
2621 if (write_access)
2622 flush_tlb_page(vma, address);
2623 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002624unlock:
2625 pte_unmap_unlock(pte, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002626 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002627}
2628
2629/*
2630 * By the time we get here, we already hold the mm semaphore
2631 */
Nick Piggin83c54072007-07-19 01:47:05 -07002632int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002633 unsigned long address, int write_access)
2634{
2635 pgd_t *pgd;
2636 pud_t *pud;
2637 pmd_t *pmd;
2638 pte_t *pte;
2639
2640 __set_current_state(TASK_RUNNING);
2641
Christoph Lameterf8891e52006-06-30 01:55:45 -07002642 count_vm_event(PGFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002643
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002644 if (unlikely(is_vm_hugetlb_page(vma)))
2645 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002648 pud = pud_alloc(mm, pgd, address);
2649 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002650 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651 pmd = pmd_alloc(mm, pud, address);
2652 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002653 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002654 pte = pte_alloc_map(mm, pmd, address);
2655 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002656 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002657
Hugh Dickinsc74df322005-10-29 18:16:23 -07002658 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002659}
2660
2661#ifndef __PAGETABLE_PUD_FOLDED
2662/*
2663 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002664 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002665 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002666int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002667{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002668 pud_t *new = pud_alloc_one(mm, address);
2669 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002670 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002671
Nick Piggin362a61a2008-05-14 06:37:36 +02002672 smp_wmb(); /* See comment in __pte_alloc */
2673
Hugh Dickins872fec12005-10-29 18:16:21 -07002674 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002675 if (pgd_present(*pgd)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08002676 pud_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002677 else
2678 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002679 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002680 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002681}
2682#endif /* __PAGETABLE_PUD_FOLDED */
2683
2684#ifndef __PAGETABLE_PMD_FOLDED
2685/*
2686 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002687 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002688 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002689int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002690{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002691 pmd_t *new = pmd_alloc_one(mm, address);
2692 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002693 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002694
Nick Piggin362a61a2008-05-14 06:37:36 +02002695 smp_wmb(); /* See comment in __pte_alloc */
2696
Hugh Dickins872fec12005-10-29 18:16:21 -07002697 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002698#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002699 if (pud_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08002700 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002701 else
2702 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002703#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002704 if (pgd_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08002705 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002706 else
2707 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002708#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002709 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002710 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002711}
2712#endif /* __PAGETABLE_PMD_FOLDED */
2713
2714int make_pages_present(unsigned long addr, unsigned long end)
2715{
2716 int ret, len, write;
2717 struct vm_area_struct * vma;
2718
2719 vma = find_vma(current->mm, addr);
2720 if (!vma)
2721 return -1;
2722 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02002723 BUG_ON(addr >= end);
2724 BUG_ON(end > vma->vm_end);
Rolf Eike Beer68e116a2007-07-15 23:38:03 -07002725 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002726 ret = get_user_pages(current, current->mm, addr,
2727 len, write, 0, NULL, NULL);
2728 if (ret < 0)
2729 return ret;
2730 return ret == len ? 0 : -1;
2731}
2732
Linus Torvalds1da177e2005-04-16 15:20:36 -07002733#if !defined(__HAVE_ARCH_GATE_AREA)
2734
2735#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002736static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002737
2738static int __init gate_vma_init(void)
2739{
2740 gate_vma.vm_mm = NULL;
2741 gate_vma.vm_start = FIXADDR_USER_START;
2742 gate_vma.vm_end = FIXADDR_USER_END;
Roland McGrathb6558c42007-01-26 00:56:47 -08002743 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
2744 gate_vma.vm_page_prot = __P101;
Roland McGrathf47aef52007-01-26 00:56:49 -08002745 /*
2746 * Make sure the vDSO gets into every core dump.
2747 * Dumping its contents makes post-mortem fully interpretable later
2748 * without matching up the same kernel and hardware config to see
2749 * what PC values meant.
2750 */
2751 gate_vma.vm_flags |= VM_ALWAYSDUMP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002752 return 0;
2753}
2754__initcall(gate_vma_init);
2755#endif
2756
2757struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2758{
2759#ifdef AT_SYSINFO_EHDR
2760 return &gate_vma;
2761#else
2762 return NULL;
2763#endif
2764}
2765
2766int in_gate_area_no_task(unsigned long addr)
2767{
2768#ifdef AT_SYSINFO_EHDR
2769 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2770 return 1;
2771#endif
2772 return 0;
2773}
2774
2775#endif /* __HAVE_ARCH_GATE_AREA */
David Howells0ec76a12006-09-27 01:50:15 -07002776
Rik van Riel28b2ee22008-07-23 21:27:05 -07002777#ifdef CONFIG_HAVE_IOREMAP_PROT
2778static resource_size_t follow_phys(struct vm_area_struct *vma,
2779 unsigned long address, unsigned int flags,
2780 unsigned long *prot)
2781{
2782 pgd_t *pgd;
2783 pud_t *pud;
2784 pmd_t *pmd;
2785 pte_t *ptep, pte;
2786 spinlock_t *ptl;
2787 resource_size_t phys_addr = 0;
2788 struct mm_struct *mm = vma->vm_mm;
2789
2790 VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP)));
2791
2792 pgd = pgd_offset(mm, address);
2793 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
2794 goto no_page_table;
2795
2796 pud = pud_offset(pgd, address);
2797 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
2798 goto no_page_table;
2799
2800 pmd = pmd_offset(pud, address);
2801 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
2802 goto no_page_table;
2803
2804 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
2805 if (pmd_huge(*pmd))
2806 goto no_page_table;
2807
2808 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
2809 if (!ptep)
2810 goto out;
2811
2812 pte = *ptep;
2813 if (!pte_present(pte))
2814 goto unlock;
2815 if ((flags & FOLL_WRITE) && !pte_write(pte))
2816 goto unlock;
2817 phys_addr = pte_pfn(pte);
2818 phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */
2819
2820 *prot = pgprot_val(pte_pgprot(pte));
2821
2822unlock:
2823 pte_unmap_unlock(ptep, ptl);
2824out:
2825 return phys_addr;
2826no_page_table:
2827 return 0;
2828}
2829
2830int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
2831 void *buf, int len, int write)
2832{
2833 resource_size_t phys_addr;
2834 unsigned long prot = 0;
2835 void *maddr;
2836 int offset = addr & (PAGE_SIZE-1);
2837
2838 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
2839 return -EINVAL;
2840
2841 phys_addr = follow_phys(vma, addr, write, &prot);
2842
2843 if (!phys_addr)
2844 return -EINVAL;
2845
2846 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
2847 if (write)
2848 memcpy_toio(maddr + offset, buf, len);
2849 else
2850 memcpy_fromio(buf, maddr + offset, len);
2851 iounmap(maddr);
2852
2853 return len;
2854}
2855#endif
2856
David Howells0ec76a12006-09-27 01:50:15 -07002857/*
2858 * Access another process' address space.
2859 * Source/target buffer must be kernel space,
2860 * Do not walk the page table directly, use get_user_pages
2861 */
2862int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2863{
2864 struct mm_struct *mm;
2865 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07002866 void *old_buf = buf;
2867
2868 mm = get_task_mm(tsk);
2869 if (!mm)
2870 return 0;
2871
2872 down_read(&mm->mmap_sem);
Simon Arlott183ff222007-10-20 01:27:18 +02002873 /* ignore errors, just check how much was successfully transferred */
David Howells0ec76a12006-09-27 01:50:15 -07002874 while (len) {
2875 int bytes, ret, offset;
2876 void *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07002877 struct page *page = NULL;
David Howells0ec76a12006-09-27 01:50:15 -07002878
2879 ret = get_user_pages(tsk, mm, addr, 1,
2880 write, 1, &page, &vma);
Rik van Riel28b2ee22008-07-23 21:27:05 -07002881 if (ret <= 0) {
2882 /*
2883 * Check if this is a VM_IO | VM_PFNMAP VMA, which
2884 * we can access using slightly different code.
2885 */
2886#ifdef CONFIG_HAVE_IOREMAP_PROT
2887 vma = find_vma(mm, addr);
2888 if (!vma)
2889 break;
2890 if (vma->vm_ops && vma->vm_ops->access)
2891 ret = vma->vm_ops->access(vma, addr, buf,
2892 len, write);
2893 if (ret <= 0)
2894#endif
2895 break;
2896 bytes = ret;
David Howells0ec76a12006-09-27 01:50:15 -07002897 } else {
Rik van Riel28b2ee22008-07-23 21:27:05 -07002898 bytes = len;
2899 offset = addr & (PAGE_SIZE-1);
2900 if (bytes > PAGE_SIZE-offset)
2901 bytes = PAGE_SIZE-offset;
2902
2903 maddr = kmap(page);
2904 if (write) {
2905 copy_to_user_page(vma, page, addr,
2906 maddr + offset, buf, bytes);
2907 set_page_dirty_lock(page);
2908 } else {
2909 copy_from_user_page(vma, page, addr,
2910 buf, maddr + offset, bytes);
2911 }
2912 kunmap(page);
2913 page_cache_release(page);
David Howells0ec76a12006-09-27 01:50:15 -07002914 }
David Howells0ec76a12006-09-27 01:50:15 -07002915 len -= bytes;
2916 buf += bytes;
2917 addr += bytes;
2918 }
2919 up_read(&mm->mmap_sem);
2920 mmput(mm);
2921
2922 return buf - old_buf;
2923}
Andi Kleen03252912008-01-30 13:33:18 +01002924
2925/*
2926 * Print the name of a VMA.
2927 */
2928void print_vma_addr(char *prefix, unsigned long ip)
2929{
2930 struct mm_struct *mm = current->mm;
2931 struct vm_area_struct *vma;
2932
Ingo Molnare8bff742008-02-13 20:21:06 +01002933 /*
2934 * Do not print if we are in atomic
2935 * contexts (in exception stacks, etc.):
2936 */
2937 if (preempt_count())
2938 return;
2939
Andi Kleen03252912008-01-30 13:33:18 +01002940 down_read(&mm->mmap_sem);
2941 vma = find_vma(mm, ip);
2942 if (vma && vma->vm_file) {
2943 struct file *f = vma->vm_file;
2944 char *buf = (char *)__get_free_page(GFP_KERNEL);
2945 if (buf) {
2946 char *p, *s;
2947
Jan Blunckcf28b482008-02-14 19:38:44 -08002948 p = d_path(&f->f_path, buf, PAGE_SIZE);
Andi Kleen03252912008-01-30 13:33:18 +01002949 if (IS_ERR(p))
2950 p = "?";
2951 s = strrchr(p, '/');
2952 if (s)
2953 p = s+1;
2954 printk("%s%s[%lx+%lx]", prefix, p,
2955 vma->vm_start,
2956 vma->vm_end - vma->vm_start);
2957 free_page((unsigned long)buf);
2958 }
2959 }
2960 up_read(&current->mm->mmap_sem);
2961}