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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/memory.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
6
7/*
8 * demand-loading started 01.12.91 - seems it is high on the list of
9 * things wanted, and it should be easy to implement. - Linus
10 */
11
12/*
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
15 *
16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 * would have taken more than the 6M I have free, but it worked well as
18 * far as I could see.
19 *
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
21 */
22
23/*
24 * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 * thought has to go into this. Oh, well..
26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 * Found it. Everything seems to work now.
28 * 20.12.91 - Ok, making the swap-device changeable like the root.
29 */
30
31/*
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
34 *
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
37 *
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
39 */
40
41#include <linux/kernel_stat.h>
42#include <linux/mm.h>
43#include <linux/hugetlb.h>
44#include <linux/mman.h>
45#include <linux/swap.h>
46#include <linux/highmem.h>
47#include <linux/pagemap.h>
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>
Andrea Arcangelicddb8a52008-07-28 15:46:29 -070054#include <linux/mmu_notifier.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070055
56#include <asm/pgalloc.h>
57#include <asm/uaccess.h>
58#include <asm/tlb.h>
59#include <asm/tlbflush.h>
60#include <asm/pgtable.h>
61
62#include <linux/swapops.h>
63#include <linux/elf.h>
64
Jan Beulich42b77722008-07-23 21:27:10 -070065#include "internal.h"
66
Andy Whitcroftd41dee32005-06-23 00:07:54 -070067#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070068/* use the per-pgdat data instead for discontigmem - mbligh */
69unsigned long max_mapnr;
70struct page *mem_map;
71
72EXPORT_SYMBOL(max_mapnr);
73EXPORT_SYMBOL(mem_map);
74#endif
75
76unsigned long num_physpages;
77/*
78 * A number of key systems in x86 including ioremap() rely on the assumption
79 * that high_memory defines the upper bound on direct map memory, then end
80 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
81 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
82 * and ZONE_HIGHMEM.
83 */
84void * high_memory;
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
86EXPORT_SYMBOL(num_physpages);
87EXPORT_SYMBOL(high_memory);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088
Ingo Molnar32a93232008-02-06 22:39:44 +010089/*
90 * Randomize the address space (stacks, mmaps, brk, etc.).
91 *
92 * ( When CONFIG_COMPAT_BRK=y we exclude brk from randomization,
93 * as ancient (libc5 based) binaries can segfault. )
94 */
95int randomize_va_space __read_mostly =
96#ifdef CONFIG_COMPAT_BRK
97 1;
98#else
99 2;
100#endif
Andi Kleena62eaf12006-02-16 23:41:58 +0100101
102static int __init disable_randmaps(char *s)
103{
104 randomize_va_space = 0;
OGAWA Hirofumi9b410462006-03-31 02:30:33 -0800105 return 1;
Andi Kleena62eaf12006-02-16 23:41:58 +0100106}
107__setup("norandmaps", disable_randmaps);
108
109
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110/*
111 * If a p?d_bad entry is found while walking page tables, report
112 * the error, before resetting entry to p?d_none. Usually (but
113 * very seldom) called out from the p?d_none_or_clear_bad macros.
114 */
115
116void pgd_clear_bad(pgd_t *pgd)
117{
118 pgd_ERROR(*pgd);
119 pgd_clear(pgd);
120}
121
122void pud_clear_bad(pud_t *pud)
123{
124 pud_ERROR(*pud);
125 pud_clear(pud);
126}
127
128void pmd_clear_bad(pmd_t *pmd)
129{
130 pmd_ERROR(*pmd);
131 pmd_clear(pmd);
132}
133
134/*
135 * Note: this doesn't free the actual pages themselves. That
136 * has been handled earlier when unmapping all the memory regions.
137 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700138static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800140 pgtable_t token = pmd_pgtable(*pmd);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700141 pmd_clear(pmd);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800142 pte_free_tlb(tlb, token);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700143 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144}
145
Hugh Dickinse0da3822005-04-19 13:29:15 -0700146static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
147 unsigned long addr, unsigned long end,
148 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149{
150 pmd_t *pmd;
151 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700152 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Hugh Dickinse0da3822005-04-19 13:29:15 -0700154 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 do {
157 next = pmd_addr_end(addr, end);
158 if (pmd_none_or_clear_bad(pmd))
159 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700160 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 } while (pmd++, addr = next, addr != end);
162
Hugh Dickinse0da3822005-04-19 13:29:15 -0700163 start &= PUD_MASK;
164 if (start < floor)
165 return;
166 if (ceiling) {
167 ceiling &= PUD_MASK;
168 if (!ceiling)
169 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700171 if (end - 1 > ceiling - 1)
172 return;
173
174 pmd = pmd_offset(pud, start);
175 pud_clear(pud);
176 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177}
178
Hugh Dickinse0da3822005-04-19 13:29:15 -0700179static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
180 unsigned long addr, unsigned long end,
181 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182{
183 pud_t *pud;
184 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700185 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186
Hugh Dickinse0da3822005-04-19 13:29:15 -0700187 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 do {
190 next = pud_addr_end(addr, end);
191 if (pud_none_or_clear_bad(pud))
192 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700193 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 } while (pud++, addr = next, addr != end);
195
Hugh Dickinse0da3822005-04-19 13:29:15 -0700196 start &= PGDIR_MASK;
197 if (start < floor)
198 return;
199 if (ceiling) {
200 ceiling &= PGDIR_MASK;
201 if (!ceiling)
202 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700204 if (end - 1 > ceiling - 1)
205 return;
206
207 pud = pud_offset(pgd, start);
208 pgd_clear(pgd);
209 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210}
211
212/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700213 * This function frees user-level page tables of a process.
214 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 * Must be called with pagetable lock held.
216 */
Jan Beulich42b77722008-07-23 21:27:10 -0700217void free_pgd_range(struct mmu_gather *tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700218 unsigned long addr, unsigned long end,
219 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700220{
221 pgd_t *pgd;
222 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700223 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224
Hugh Dickinse0da3822005-04-19 13:29:15 -0700225 /*
226 * The next few lines have given us lots of grief...
227 *
228 * Why are we testing PMD* at this top level? Because often
229 * there will be no work to do at all, and we'd prefer not to
230 * go all the way down to the bottom just to discover that.
231 *
232 * Why all these "- 1"s? Because 0 represents both the bottom
233 * of the address space and the top of it (using -1 for the
234 * top wouldn't help much: the masks would do the wrong thing).
235 * The rule is that addr 0 and floor 0 refer to the bottom of
236 * the address space, but end 0 and ceiling 0 refer to the top
237 * Comparisons need to use "end - 1" and "ceiling - 1" (though
238 * that end 0 case should be mythical).
239 *
240 * Wherever addr is brought up or ceiling brought down, we must
241 * be careful to reject "the opposite 0" before it confuses the
242 * subsequent tests. But what about where end is brought down
243 * by PMD_SIZE below? no, end can't go down to 0 there.
244 *
245 * Whereas we round start (addr) and ceiling down, by different
246 * masks at different levels, in order to test whether a table
247 * now has no other vmas using it, so can be freed, we don't
248 * bother to round floor or end up - the tests don't need that.
249 */
250
251 addr &= PMD_MASK;
252 if (addr < floor) {
253 addr += PMD_SIZE;
254 if (!addr)
255 return;
256 }
257 if (ceiling) {
258 ceiling &= PMD_MASK;
259 if (!ceiling)
260 return;
261 }
262 if (end - 1 > ceiling - 1)
263 end -= PMD_SIZE;
264 if (addr > end - 1)
265 return;
266
267 start = addr;
Jan Beulich42b77722008-07-23 21:27:10 -0700268 pgd = pgd_offset(tlb->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700269 do {
270 next = pgd_addr_end(addr, end);
271 if (pgd_none_or_clear_bad(pgd))
272 continue;
Jan Beulich42b77722008-07-23 21:27:10 -0700273 free_pud_range(tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700275}
276
Jan Beulich42b77722008-07-23 21:27:10 -0700277void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700278 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700279{
280 while (vma) {
281 struct vm_area_struct *next = vma->vm_next;
282 unsigned long addr = vma->vm_start;
283
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700284 /*
285 * Hide vma from rmap and vmtruncate before freeing pgtables
286 */
287 anon_vma_unlink(vma);
288 unlink_file_vma(vma);
289
David Gibson9da61ae2006-03-22 00:08:57 -0800290 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700291 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700292 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700293 } else {
294 /*
295 * Optimization: gather nearby vmas into one call down
296 */
297 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800298 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700299 vma = next;
300 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700301 anon_vma_unlink(vma);
302 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700303 }
304 free_pgd_range(tlb, addr, vma->vm_end,
305 floor, next? next->vm_start: ceiling);
306 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700307 vma = next;
308 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700309}
310
Hugh Dickins1bb36302005-10-29 18:16:22 -0700311int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700312{
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800313 pgtable_t new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700314 if (!new)
315 return -ENOMEM;
316
Nick Piggin362a61a2008-05-14 06:37:36 +0200317 /*
318 * Ensure all pte setup (eg. pte page lock and page clearing) are
319 * visible before the pte is made visible to other CPUs by being
320 * put into page tables.
321 *
322 * The other side of the story is the pointer chasing in the page
323 * table walking code (when walking the page table without locking;
324 * ie. most of the time). Fortunately, these data accesses consist
325 * of a chain of data-dependent loads, meaning most CPUs (alpha
326 * being the notable exception) will already guarantee loads are
327 * seen in-order. See the alpha page table accessors for the
328 * smp_read_barrier_depends() barriers in page table walking code.
329 */
330 smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */
331
Hugh Dickinsc74df322005-10-29 18:16:23 -0700332 spin_lock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800333 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 mm->nr_ptes++;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 pmd_populate(mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800336 new = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700337 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700338 spin_unlock(&mm->page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800339 if (new)
340 pte_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700341 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700342}
343
Hugh Dickins1bb36302005-10-29 18:16:22 -0700344int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700346 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
347 if (!new)
348 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349
Nick Piggin362a61a2008-05-14 06:37:36 +0200350 smp_wmb(); /* See comment in __pte_alloc */
351
Hugh Dickins1bb36302005-10-29 18:16:22 -0700352 spin_lock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800353 if (!pmd_present(*pmd)) { /* Has another populated it ? */
Hugh Dickins1bb36302005-10-29 18:16:22 -0700354 pmd_populate_kernel(&init_mm, pmd, new);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800355 new = NULL;
356 }
Hugh Dickins1bb36302005-10-29 18:16:22 -0700357 spin_unlock(&init_mm.page_table_lock);
Martin Schwidefsky2f569af2008-02-08 04:22:04 -0800358 if (new)
359 pte_free_kernel(&init_mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700360 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361}
362
Hugh Dickinsae859762005-10-29 18:16:05 -0700363static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
364{
365 if (file_rss)
366 add_mm_counter(mm, file_rss, file_rss);
367 if (anon_rss)
368 add_mm_counter(mm, anon_rss, anon_rss);
369}
370
Linus Torvalds1da177e2005-04-16 15:20:36 -0700371/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800372 * This function is called to print an error when a bad pte
373 * is found. For example, we might have a PFN-mapped pte in
374 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700375 *
376 * The calling function must still handle the error.
377 */
Adrian Bunk15f59ad2008-07-25 19:46:23 -0700378static void print_bad_pte(struct vm_area_struct *vma, pte_t pte,
379 unsigned long vaddr)
Nick Pigginb5810032005-10-29 18:16:12 -0700380{
381 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
382 "vm_flags = %lx, vaddr = %lx\n",
383 (long long)pte_val(pte),
384 (vma->vm_mm == current->mm ? current->comm : "???"),
385 vma->vm_flags, vaddr);
386 dump_stack();
387}
388
Linus Torvalds67121172005-12-11 20:38:17 -0800389static inline int is_cow_mapping(unsigned int flags)
390{
391 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
392}
393
Nick Pigginb5810032005-10-29 18:16:12 -0700394/*
Nick Piggin7e675132008-04-28 02:13:00 -0700395 * vm_normal_page -- This function gets the "struct page" associated with a pte.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800396 *
Nick Piggin7e675132008-04-28 02:13:00 -0700397 * "Special" mappings do not wish to be associated with a "struct page" (either
398 * it doesn't exist, or it exists but they don't want to touch it). In this
399 * case, NULL is returned here. "Normal" mappings do have a struct page.
Jared Hulbertb379d792008-04-28 02:12:58 -0700400 *
Nick Piggin7e675132008-04-28 02:13:00 -0700401 * There are 2 broad cases. Firstly, an architecture may define a pte_special()
402 * pte bit, in which case this function is trivial. Secondly, an architecture
403 * may not have a spare pte bit, which requires a more complicated scheme,
404 * described below.
405 *
406 * A raw VM_PFNMAP mapping (ie. one that is not COWed) is always considered a
407 * special mapping (even if there are underlying and valid "struct pages").
408 * COWed pages of a VM_PFNMAP are always normal.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800409 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700410 * The way we recognize COWed pages within VM_PFNMAP mappings is through the
411 * rules set up by "remap_pfn_range()": the vma will have the VM_PFNMAP bit
Nick Piggin7e675132008-04-28 02:13:00 -0700412 * set, and the vm_pgoff will point to the first PFN mapped: thus every special
413 * mapping will always honor the rule
Linus Torvalds6aab3412005-11-28 14:34:23 -0800414 *
415 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
416 *
Nick Piggin7e675132008-04-28 02:13:00 -0700417 * And for normal mappings this is false.
Jared Hulbertb379d792008-04-28 02:12:58 -0700418 *
Nick Piggin7e675132008-04-28 02:13:00 -0700419 * This restricts such mappings to be a linear translation from virtual address
420 * to pfn. To get around this restriction, we allow arbitrary mappings so long
421 * as the vma is not a COW mapping; in that case, we know that all ptes are
422 * special (because none can have been COWed).
Jared Hulbertb379d792008-04-28 02:12:58 -0700423 *
424 *
Nick Piggin7e675132008-04-28 02:13:00 -0700425 * In order to support COW of arbitrary special mappings, we have VM_MIXEDMAP.
426 *
Jared Hulbertb379d792008-04-28 02:12:58 -0700427 * VM_MIXEDMAP mappings can likewise contain memory with or without "struct
428 * page" backing, however the difference is that _all_ pages with a struct
429 * page (that is, those where pfn_valid is true) are refcounted and considered
430 * normal pages by the VM. The disadvantage is that pages are refcounted
431 * (which can be slower and simply not an option for some PFNMAP users). The
432 * advantage is that we don't have to follow the strict linearity rule of
433 * PFNMAP mappings in order to support COWable mappings.
434 *
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800435 */
Nick Piggin7e675132008-04-28 02:13:00 -0700436#ifdef __HAVE_ARCH_PTE_SPECIAL
437# define HAVE_PTE_SPECIAL 1
438#else
439# define HAVE_PTE_SPECIAL 0
440#endif
441struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
442 pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800443{
Nick Piggin7e675132008-04-28 02:13:00 -0700444 unsigned long pfn;
445
446 if (HAVE_PTE_SPECIAL) {
447 if (likely(!pte_special(pte))) {
448 VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
449 return pte_page(pte);
450 }
451 VM_BUG_ON(!(vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP)));
452 return NULL;
453 }
454
455 /* !HAVE_PTE_SPECIAL case follows: */
456
457 pfn = pte_pfn(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800458
Jared Hulbertb379d792008-04-28 02:12:58 -0700459 if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
460 if (vma->vm_flags & VM_MIXEDMAP) {
461 if (!pfn_valid(pfn))
462 return NULL;
463 goto out;
464 } else {
Nick Piggin7e675132008-04-28 02:13:00 -0700465 unsigned long off;
466 off = (addr - vma->vm_start) >> PAGE_SHIFT;
Jared Hulbertb379d792008-04-28 02:12:58 -0700467 if (pfn == vma->vm_pgoff + off)
468 return NULL;
469 if (!is_cow_mapping(vma->vm_flags))
470 return NULL;
471 }
Linus Torvalds6aab3412005-11-28 14:34:23 -0800472 }
473
Nick Piggin7e675132008-04-28 02:13:00 -0700474 VM_BUG_ON(!pfn_valid(pfn));
Linus Torvalds6aab3412005-11-28 14:34:23 -0800475
476 /*
Nick Piggin7e675132008-04-28 02:13:00 -0700477 * NOTE! We still have PageReserved() pages in the page tables.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800478 *
Nick Piggin7e675132008-04-28 02:13:00 -0700479 * eg. VDSO mappings can cause them to exist.
Linus Torvalds6aab3412005-11-28 14:34:23 -0800480 */
Jared Hulbertb379d792008-04-28 02:12:58 -0700481out:
Linus Torvalds6aab3412005-11-28 14:34:23 -0800482 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800483}
484
485/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486 * copy one vm_area from one task to the other. Assumes the page tables
487 * already present in the new task to be cleared in the whole range
488 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 */
490
Hugh Dickins8c103762005-10-29 18:16:13 -0700491static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700493 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700494 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
Nick Pigginb5810032005-10-29 18:16:12 -0700496 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 pte_t pte = *src_pte;
498 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499
500 /* pte contains position in swap or file, so copy. */
501 if (unlikely(!pte_present(pte))) {
502 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700503 swp_entry_t entry = pte_to_swp_entry(pte);
504
505 swap_duplicate(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 /* make sure dst_mm is on swapoff's mmlist. */
507 if (unlikely(list_empty(&dst_mm->mmlist))) {
508 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700509 if (list_empty(&dst_mm->mmlist))
510 list_add(&dst_mm->mmlist,
511 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512 spin_unlock(&mmlist_lock);
513 }
Christoph Lameter06972122006-06-23 02:03:35 -0700514 if (is_write_migration_entry(entry) &&
515 is_cow_mapping(vm_flags)) {
516 /*
517 * COW mappings require pages in both parent
518 * and child to be set to read.
519 */
520 make_migration_entry_read(&entry);
521 pte = swp_entry_to_pte(entry);
522 set_pte_at(src_mm, addr, src_pte, pte);
523 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700525 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 }
527
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 /*
529 * If it's a COW mapping, write protect it both
530 * in the parent and the child
531 */
Linus Torvalds67121172005-12-11 20:38:17 -0800532 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 ptep_set_wrprotect(src_mm, addr, src_pte);
Zachary Amsden3dc90792006-09-30 23:29:30 -0700534 pte = pte_wrprotect(pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 }
536
537 /*
538 * If it's a shared mapping, mark it clean in
539 * the child
540 */
541 if (vm_flags & VM_SHARED)
542 pte = pte_mkclean(pte);
543 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800544
545 page = vm_normal_page(vma, addr, pte);
546 if (page) {
547 get_page(page);
Nick Pigginc97a9e12007-05-16 22:11:21 -0700548 page_dup_rmap(page, vma, addr);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800549 rss[!!PageAnon(page)]++;
550 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700551
552out_set_pte:
553 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554}
555
556static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
557 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
558 unsigned long addr, unsigned long end)
559{
560 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700561 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700562 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700563 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
565again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700566 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700567 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568 if (!dst_pte)
569 return -ENOMEM;
570 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700571 src_ptl = pte_lockptr(src_mm, src_pmd);
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700572 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700573 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574
Linus Torvalds1da177e2005-04-16 15:20:36 -0700575 do {
576 /*
577 * We are holding two locks at this point - either of them
578 * could generate latencies in another task on another CPU.
579 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700580 if (progress >= 32) {
581 progress = 0;
582 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100583 spin_needbreak(src_ptl) || spin_needbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700584 break;
585 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 if (pte_none(*src_pte)) {
587 progress++;
588 continue;
589 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700590 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 progress += 8;
592 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700594 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -0700595 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700597 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700598 pte_unmap_unlock(dst_pte - 1, dst_ptl);
599 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 if (addr != end)
601 goto again;
602 return 0;
603}
604
605static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
606 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
607 unsigned long addr, unsigned long end)
608{
609 pmd_t *src_pmd, *dst_pmd;
610 unsigned long next;
611
612 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
613 if (!dst_pmd)
614 return -ENOMEM;
615 src_pmd = pmd_offset(src_pud, addr);
616 do {
617 next = pmd_addr_end(addr, end);
618 if (pmd_none_or_clear_bad(src_pmd))
619 continue;
620 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
621 vma, addr, next))
622 return -ENOMEM;
623 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
624 return 0;
625}
626
627static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
628 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
629 unsigned long addr, unsigned long end)
630{
631 pud_t *src_pud, *dst_pud;
632 unsigned long next;
633
634 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
635 if (!dst_pud)
636 return -ENOMEM;
637 src_pud = pud_offset(src_pgd, addr);
638 do {
639 next = pud_addr_end(addr, end);
640 if (pud_none_or_clear_bad(src_pud))
641 continue;
642 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
643 vma, addr, next))
644 return -ENOMEM;
645 } while (dst_pud++, src_pud++, addr = next, addr != end);
646 return 0;
647}
648
649int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
650 struct vm_area_struct *vma)
651{
652 pgd_t *src_pgd, *dst_pgd;
653 unsigned long next;
654 unsigned long addr = vma->vm_start;
655 unsigned long end = vma->vm_end;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700656 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657
Nick Piggind9928952005-08-28 16:49:11 +1000658 /*
659 * Don't copy ptes where a page fault will fill them correctly.
660 * Fork becomes much lighter when there are big shared or private
661 * readonly mappings. The tradeoff is that copy_page_range is more
662 * efficient than faulting.
663 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800664 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000665 if (!vma->anon_vma)
666 return 0;
667 }
668
Linus Torvalds1da177e2005-04-16 15:20:36 -0700669 if (is_vm_hugetlb_page(vma))
670 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
671
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700672 /*
673 * We need to invalidate the secondary MMU mappings only when
674 * there could be a permission downgrade on the ptes of the
675 * parent mm. And a permission downgrade will only happen if
676 * is_cow_mapping() returns true.
677 */
678 if (is_cow_mapping(vma->vm_flags))
679 mmu_notifier_invalidate_range_start(src_mm, addr, end);
680
681 ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 dst_pgd = pgd_offset(dst_mm, addr);
683 src_pgd = pgd_offset(src_mm, addr);
684 do {
685 next = pgd_addr_end(addr, end);
686 if (pgd_none_or_clear_bad(src_pgd))
687 continue;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700688 if (unlikely(copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
689 vma, addr, next))) {
690 ret = -ENOMEM;
691 break;
692 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700694
695 if (is_cow_mapping(vma->vm_flags))
696 mmu_notifier_invalidate_range_end(src_mm,
697 vma->vm_start, end);
698 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699}
700
Robin Holt51c6f662005-11-13 16:06:42 -0800701static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700702 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700703 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800704 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705{
Nick Pigginb5810032005-10-29 18:16:12 -0700706 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700707 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700708 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700709 int file_rss = 0;
710 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711
Hugh Dickins508034a2005-10-29 18:16:30 -0700712 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700713 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 do {
715 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800716 if (pte_none(ptent)) {
717 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700718 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800719 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800720
721 (*zap_work) -= PAGE_SIZE;
722
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800724 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800725
Linus Torvalds6aab3412005-11-28 14:34:23 -0800726 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 if (unlikely(details) && page) {
728 /*
729 * unmap_shared_mapping_pages() wants to
730 * invalidate cache without truncating:
731 * unmap shared but keep private pages.
732 */
733 if (details->check_mapping &&
734 details->check_mapping != page->mapping)
735 continue;
736 /*
737 * Each page->index must be checked when
738 * invalidating or truncating nonlinear.
739 */
740 if (details->nonlinear_vma &&
741 (page->index < details->first_index ||
742 page->index > details->last_index))
743 continue;
744 }
Nick Pigginb5810032005-10-29 18:16:12 -0700745 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700746 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 tlb_remove_tlb_entry(tlb, pte, addr);
748 if (unlikely(!page))
749 continue;
750 if (unlikely(details) && details->nonlinear_vma
751 && linear_page_index(details->nonlinear_vma,
752 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700753 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700755 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700756 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700757 else {
758 if (pte_dirty(ptent))
759 set_page_dirty(page);
760 if (pte_young(ptent))
Ken Chendaa88c82007-02-10 01:43:18 -0800761 SetPageReferenced(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700762 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700763 }
Nick Piggin7de6b802006-12-22 01:09:33 -0800764 page_remove_rmap(page, vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765 tlb_remove_page(tlb, page);
766 continue;
767 }
768 /*
769 * If details->check_mapping, we leave swap entries;
770 * if details->nonlinear_vma, we leave file entries.
771 */
772 if (unlikely(details))
773 continue;
774 if (!pte_file(ptent))
775 free_swap_and_cache(pte_to_swp_entry(ptent));
Zachary Amsden9888a1c2006-09-30 23:29:31 -0700776 pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800777 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700778
Hugh Dickins86d912f2005-10-29 18:16:14 -0700779 add_mm_rss(mm, file_rss, anon_rss);
Zachary Amsden6606c3e2006-09-30 23:29:33 -0700780 arch_leave_lazy_mmu_mode();
Hugh Dickins508034a2005-10-29 18:16:30 -0700781 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800782
783 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784}
785
Robin Holt51c6f662005-11-13 16:06:42 -0800786static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700787 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800789 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790{
791 pmd_t *pmd;
792 unsigned long next;
793
794 pmd = pmd_offset(pud, addr);
795 do {
796 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800797 if (pmd_none_or_clear_bad(pmd)) {
798 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700799 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800800 }
801 next = zap_pte_range(tlb, vma, pmd, addr, next,
802 zap_work, details);
803 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
804
805 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806}
807
Robin Holt51c6f662005-11-13 16:06:42 -0800808static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700809 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800811 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812{
813 pud_t *pud;
814 unsigned long next;
815
816 pud = pud_offset(pgd, addr);
817 do {
818 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800819 if (pud_none_or_clear_bad(pud)) {
820 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800822 }
823 next = zap_pmd_range(tlb, vma, pud, addr, next,
824 zap_work, details);
825 } while (pud++, addr = next, (addr != end && *zap_work > 0));
826
827 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700828}
829
Robin Holt51c6f662005-11-13 16:06:42 -0800830static unsigned long unmap_page_range(struct mmu_gather *tlb,
831 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800833 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834{
835 pgd_t *pgd;
836 unsigned long next;
837
838 if (details && !details->check_mapping && !details->nonlinear_vma)
839 details = NULL;
840
841 BUG_ON(addr >= end);
842 tlb_start_vma(tlb, vma);
843 pgd = pgd_offset(vma->vm_mm, addr);
844 do {
845 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800846 if (pgd_none_or_clear_bad(pgd)) {
847 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800849 }
850 next = zap_pud_range(tlb, vma, pgd, addr, next,
851 zap_work, details);
852 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700853 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800854
855 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856}
857
858#ifdef CONFIG_PREEMPT
859# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
860#else
861/* No preempt: go for improved straight-line efficiency */
862# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
863#endif
864
865/**
866 * unmap_vmas - unmap a range of memory covered by a list of vma's
867 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 * @vma: the starting vma
869 * @start_addr: virtual address at which to start unmapping
870 * @end_addr: virtual address at which to end unmapping
871 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
872 * @details: details of nonlinear truncation or shared cache invalidation
873 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700874 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700875 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700876 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700878 * We aim to not hold locks for too long (for scheduling latency reasons).
879 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700880 * return the ending mmu_gather to the caller.
881 *
882 * Only addresses between `start' and `end' will be unmapped.
883 *
884 * The VMA list must be sorted in ascending virtual address order.
885 *
886 * unmap_vmas() assumes that the caller will flush the whole unmapped address
887 * range after unmap_vmas() returns. So the only responsibility here is to
888 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
889 * drops the lock and schedules.
890 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700891unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700892 struct vm_area_struct *vma, unsigned long start_addr,
893 unsigned long end_addr, unsigned long *nr_accounted,
894 struct zap_details *details)
895{
Robin Holt51c6f662005-11-13 16:06:42 -0800896 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
898 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700899 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700901 int fullmm = (*tlbp)->fullmm;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700902 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700904 mmu_notifier_invalidate_range_start(mm, start_addr, end_addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700905 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 unsigned long end;
907
908 start = max(vma->vm_start, start_addr);
909 if (start >= vma->vm_end)
910 continue;
911 end = min(vma->vm_end, end_addr);
912 if (end <= vma->vm_start)
913 continue;
914
915 if (vma->vm_flags & VM_ACCOUNT)
916 *nr_accounted += (end - start) >> PAGE_SHIFT;
917
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919 if (!tlb_start_valid) {
920 tlb_start = start;
921 tlb_start_valid = 1;
922 }
923
Robin Holt51c6f662005-11-13 16:06:42 -0800924 if (unlikely(is_vm_hugetlb_page(vma))) {
Andi Kleena137e1c2008-07-23 21:27:43 -0700925 /*
926 * It is undesirable to test vma->vm_file as it
927 * should be non-null for valid hugetlb area.
928 * However, vm_file will be NULL in the error
929 * cleanup path of do_mmap_pgoff. When
930 * hugetlbfs ->mmap method fails,
931 * do_mmap_pgoff() nullifies vma->vm_file
932 * before calling this function to clean up.
933 * Since no pte has actually been setup, it is
934 * safe to do nothing in this case.
935 */
936 if (vma->vm_file) {
937 unmap_hugepage_range(vma, start, end, NULL);
938 zap_work -= (end - start) /
Andi Kleena5516432008-07-23 21:27:41 -0700939 pages_per_huge_page(hstate_vma(vma));
Andi Kleena137e1c2008-07-23 21:27:43 -0700940 }
941
Robin Holt51c6f662005-11-13 16:06:42 -0800942 start = end;
943 } else
944 start = unmap_page_range(*tlbp, vma,
945 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700946
Robin Holt51c6f662005-11-13 16:06:42 -0800947 if (zap_work > 0) {
948 BUG_ON(start != end);
949 break;
950 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951
952 tlb_finish_mmu(*tlbp, tlb_start, start);
953
954 if (need_resched() ||
Nick Piggin95c354f2008-01-30 13:31:20 +0100955 (i_mmap_lock && spin_needbreak(i_mmap_lock))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700956 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700957 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700958 goto out;
959 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700961 }
962
Hugh Dickins508034a2005-10-29 18:16:30 -0700963 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800965 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 }
967 }
968out:
Andrea Arcangelicddb8a52008-07-28 15:46:29 -0700969 mmu_notifier_invalidate_range_end(mm, start_addr, end_addr);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700970 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971}
972
973/**
974 * zap_page_range - remove user pages in a given range
975 * @vma: vm_area_struct holding the applicable pages
976 * @address: starting address of pages to zap
977 * @size: number of bytes to zap
978 * @details: details of nonlinear truncation or shared cache invalidation
979 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700980unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 unsigned long size, struct zap_details *details)
982{
983 struct mm_struct *mm = vma->vm_mm;
984 struct mmu_gather *tlb;
985 unsigned long end = address + size;
986 unsigned long nr_accounted = 0;
987
Linus Torvalds1da177e2005-04-16 15:20:36 -0700988 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700989 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700990 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700991 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
992 if (tlb)
993 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700994 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995}
996
Jack Steinerc627f9c2008-07-29 22:33:53 -0700997/**
998 * zap_vma_ptes - remove ptes mapping the vma
999 * @vma: vm_area_struct holding ptes to be zapped
1000 * @address: starting address of pages to zap
1001 * @size: number of bytes to zap
1002 *
1003 * This function only unmaps ptes assigned to VM_PFNMAP vmas.
1004 *
1005 * The entire address range must be fully contained within the vma.
1006 *
1007 * Returns 0 if successful.
1008 */
1009int zap_vma_ptes(struct vm_area_struct *vma, unsigned long address,
1010 unsigned long size)
1011{
1012 if (address < vma->vm_start || address + size > vma->vm_end ||
1013 !(vma->vm_flags & VM_PFNMAP))
1014 return -1;
1015 zap_page_range(vma, address, size, NULL);
1016 return 0;
1017}
1018EXPORT_SYMBOL_GPL(zap_vma_ptes);
1019
Linus Torvalds1da177e2005-04-16 15:20:36 -07001020/*
1021 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022 */
Linus Torvalds6aab3412005-11-28 14:34:23 -08001023struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001024 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001025{
1026 pgd_t *pgd;
1027 pud_t *pud;
1028 pmd_t *pmd;
1029 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001030 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001032 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001033
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001034 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
1035 if (!IS_ERR(page)) {
1036 BUG_ON(flags & FOLL_GET);
1037 goto out;
1038 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001039
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001040 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001041 pgd = pgd_offset(mm, address);
1042 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001043 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001044
1045 pud = pud_offset(pgd, address);
Andi Kleenceb86872008-07-23 21:27:50 -07001046 if (pud_none(*pud))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001047 goto no_page_table;
Andi Kleenceb86872008-07-23 21:27:50 -07001048 if (pud_huge(*pud)) {
1049 BUG_ON(flags & FOLL_GET);
1050 page = follow_huge_pud(mm, address, pud, flags & FOLL_WRITE);
1051 goto out;
1052 }
1053 if (unlikely(pud_bad(*pud)))
1054 goto no_page_table;
1055
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 pmd = pmd_offset(pud, address);
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001057 if (pmd_none(*pmd))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001058 goto no_page_table;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001059 if (pmd_huge(*pmd)) {
1060 BUG_ON(flags & FOLL_GET);
1061 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
1062 goto out;
1063 }
Hugh Dickinsaeed5fc2008-05-06 20:49:23 +01001064 if (unlikely(pmd_bad(*pmd)))
1065 goto no_page_table;
1066
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001067 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001068
1069 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001070 if (!pte_present(pte))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001071 goto no_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001072 if ((flags & FOLL_WRITE) && !pte_write(pte))
1073 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001074 page = vm_normal_page(vma, address, pte);
1075 if (unlikely(!page))
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001076 goto bad_page;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001077
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001078 if (flags & FOLL_GET)
1079 get_page(page);
1080 if (flags & FOLL_TOUCH) {
1081 if ((flags & FOLL_WRITE) &&
1082 !pte_dirty(pte) && !PageDirty(page))
1083 set_page_dirty(page);
1084 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001085 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001086unlock:
1087 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001088out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001089 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001091bad_page:
1092 pte_unmap_unlock(ptep, ptl);
1093 return ERR_PTR(-EFAULT);
1094
1095no_page:
1096 pte_unmap_unlock(ptep, ptl);
1097 if (!pte_none(pte))
1098 return page;
1099 /* Fall through to ZERO_PAGE handling */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001100no_page_table:
1101 /*
1102 * When core dumping an enormous anonymous area that nobody
1103 * has touched so far, we don't want to allocate page tables.
1104 */
1105 if (flags & FOLL_ANON) {
Nick Piggin557ed1f2007-10-16 01:24:40 -07001106 page = ZERO_PAGE(0);
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001107 if (flags & FOLL_GET)
1108 get_page(page);
1109 BUG_ON(flags & FOLL_WRITE);
1110 }
1111 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112}
1113
Linus Torvalds672ca282008-06-23 11:21:37 -07001114/* Can we do the FOLL_ANON optimization? */
1115static inline int use_zero_page(struct vm_area_struct *vma)
1116{
1117 /*
1118 * We don't want to optimize FOLL_ANON for make_pages_present()
1119 * when it tries to page in a VM_LOCKED region. As to VM_SHARED,
1120 * we want to get the page from the page tables to make sure
1121 * that we serialize and update with any other user of that
1122 * mapping.
1123 */
1124 if (vma->vm_flags & (VM_LOCKED | VM_SHARED))
1125 return 0;
1126 /*
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001127 * And if we have a fault routine, it's not an anonymous region.
Linus Torvalds672ca282008-06-23 11:21:37 -07001128 */
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001129 return !vma->vm_ops || !vma->vm_ops->fault;
Linus Torvalds672ca282008-06-23 11:21:37 -07001130}
1131
Linus Torvalds1da177e2005-04-16 15:20:36 -07001132int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1133 unsigned long start, int len, int write, int force,
1134 struct page **pages, struct vm_area_struct **vmas)
1135{
1136 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001137 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001138
Jonathan Corbet900cf082008-02-11 16:17:33 -07001139 if (len <= 0)
1140 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001141 /*
1142 * Require read or write permissions.
1143 * If 'force' is set, we only require the "MAY" flags.
1144 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001145 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1146 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 i = 0;
1148
1149 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001150 struct vm_area_struct *vma;
1151 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001152
1153 vma = find_extend_vma(mm, start);
1154 if (!vma && in_gate_area(tsk, start)) {
1155 unsigned long pg = start & PAGE_MASK;
1156 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
1157 pgd_t *pgd;
1158 pud_t *pud;
1159 pmd_t *pmd;
1160 pte_t *pte;
1161 if (write) /* user gate pages are read-only */
1162 return i ? : -EFAULT;
1163 if (pg > TASK_SIZE)
1164 pgd = pgd_offset_k(pg);
1165 else
1166 pgd = pgd_offset_gate(mm, pg);
1167 BUG_ON(pgd_none(*pgd));
1168 pud = pud_offset(pgd, pg);
1169 BUG_ON(pud_none(*pud));
1170 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001171 if (pmd_none(*pmd))
1172 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001173 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001174 if (pte_none(*pte)) {
1175 pte_unmap(pte);
1176 return i ? : -EFAULT;
1177 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001179 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001180 pages[i] = page;
1181 if (page)
1182 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183 }
1184 pte_unmap(pte);
1185 if (vmas)
1186 vmas[i] = gate_vma;
1187 i++;
1188 start += PAGE_SIZE;
1189 len--;
1190 continue;
1191 }
1192
Linus Torvalds1ff80382005-12-12 16:24:33 -08001193 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001194 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001195 return i ? : -EFAULT;
1196
1197 if (is_vm_hugetlb_page(vma)) {
1198 i = follow_hugetlb_page(mm, vma, pages, vmas,
Adam Litke5b23dbe2007-11-14 16:59:33 -08001199 &start, &len, i, write);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001200 continue;
1201 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001202
1203 foll_flags = FOLL_TOUCH;
1204 if (pages)
1205 foll_flags |= FOLL_GET;
Linus Torvalds672ca282008-06-23 11:21:37 -07001206 if (!write && use_zero_page(vma))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001207 foll_flags |= FOLL_ANON;
1208
Linus Torvalds1da177e2005-04-16 15:20:36 -07001209 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001210 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001211
Ethan Solomita462e00c2007-07-15 23:38:16 -07001212 /*
1213 * If tsk is ooming, cut off its access to large memory
1214 * allocations. It has a pending SIGKILL, but it can't
1215 * be processed until returning to user space.
1216 */
1217 if (unlikely(test_tsk_thread_flag(tsk, TIF_MEMDIE)))
Oleg Nesterov7a36a752008-07-04 09:59:28 -07001218 return i ? i : -ENOMEM;
Ethan Solomita462e00c2007-07-15 23:38:16 -07001219
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001220 if (write)
1221 foll_flags |= FOLL_WRITE;
1222
1223 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001224 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001225 int ret;
Nick Piggin83c54072007-07-19 01:47:05 -07001226 ret = handle_mm_fault(mm, vma, start,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001227 foll_flags & FOLL_WRITE);
Nick Piggin83c54072007-07-19 01:47:05 -07001228 if (ret & VM_FAULT_ERROR) {
1229 if (ret & VM_FAULT_OOM)
1230 return i ? i : -ENOMEM;
1231 else if (ret & VM_FAULT_SIGBUS)
1232 return i ? i : -EFAULT;
1233 BUG();
1234 }
1235 if (ret & VM_FAULT_MAJOR)
1236 tsk->maj_flt++;
1237 else
1238 tsk->min_flt++;
1239
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001240 /*
Nick Piggin83c54072007-07-19 01:47:05 -07001241 * The VM_FAULT_WRITE bit tells us that
1242 * do_wp_page has broken COW when necessary,
1243 * even if maybe_mkwrite decided not to set
1244 * pte_write. We can thus safely do subsequent
1245 * page lookups as if they were reads.
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001246 */
1247 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001248 foll_flags &= ~FOLL_WRITE;
Nick Piggin83c54072007-07-19 01:47:05 -07001249
Benjamin Herrenschmidt7f7bbbe2006-10-06 00:43:53 -07001250 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001251 }
Linus Torvalds89f5b7d2008-06-20 11:18:25 -07001252 if (IS_ERR(page))
1253 return i ? i : PTR_ERR(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001255 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001256
Russell Kinga6f36be2006-12-30 22:24:19 +00001257 flush_anon_page(vma, page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001258 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001259 }
1260 if (vmas)
1261 vmas[i] = vma;
1262 i++;
1263 start += PAGE_SIZE;
1264 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001265 } while (len && start < vma->vm_end);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001266 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001267 return i;
1268}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001269EXPORT_SYMBOL(get_user_pages);
1270
Harvey Harrison920c7a52008-02-04 22:29:26 -08001271pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
1272 spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001273{
1274 pgd_t * pgd = pgd_offset(mm, addr);
1275 pud_t * pud = pud_alloc(mm, pgd, addr);
1276 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001277 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001278 if (pmd)
1279 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1280 }
1281 return NULL;
1282}
1283
Linus Torvalds1da177e2005-04-16 15:20:36 -07001284/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001285 * This is the old fallback for page remapping.
1286 *
1287 * For historical reasons, it only allows reserved pages. Only
1288 * old drivers should use this, and they needed to mark their
1289 * pages reserved for the old functions anyway.
1290 */
Nick Piggin423bad602008-04-28 02:13:01 -07001291static int insert_page(struct vm_area_struct *vma, unsigned long addr,
1292 struct page *page, pgprot_t prot)
Linus Torvalds238f58d2005-11-29 13:01:56 -08001293{
Nick Piggin423bad602008-04-28 02:13:01 -07001294 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001295 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001296 pte_t *pte;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001297 spinlock_t *ptl;
1298
Balbir Singhe1a1cd52008-02-07 00:14:02 -08001299 retval = mem_cgroup_charge(page, mm, GFP_KERNEL);
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001300 if (retval)
1301 goto out;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001302
1303 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001304 if (PageAnon(page))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001305 goto out_uncharge;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001306 retval = -ENOMEM;
1307 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001308 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001309 if (!pte)
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001310 goto out_uncharge;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001311 retval = -EBUSY;
1312 if (!pte_none(*pte))
1313 goto out_unlock;
1314
1315 /* Ok, finally just insert the thing.. */
1316 get_page(page);
1317 inc_mm_counter(mm, file_rss);
1318 page_add_file_rmap(page);
1319 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1320
1321 retval = 0;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001322 pte_unmap_unlock(pte, ptl);
1323 return retval;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001324out_unlock:
1325 pte_unmap_unlock(pte, ptl);
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001326out_uncharge:
1327 mem_cgroup_uncharge_page(page);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001328out:
1329 return retval;
1330}
1331
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001332/**
1333 * vm_insert_page - insert single page into user vma
1334 * @vma: user vma to map to
1335 * @addr: target user address of this page
1336 * @page: source kernel page
1337 *
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001338 * This allows drivers to insert individual pages they've allocated
1339 * into a user vma.
1340 *
1341 * The page has to be a nice clean _individual_ kernel allocation.
1342 * If you allocate a compound page, you need to have marked it as
1343 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001344 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001345 *
1346 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1347 * took an arbitrary page protection parameter. This doesn't allow
1348 * that. Your vma protection will have to be set up correctly, which
1349 * means that if you want a shared writable mapping, you'd better
1350 * ask for a shared writable mapping!
1351 *
1352 * The page does not need to be reserved.
1353 */
Nick Piggin423bad602008-04-28 02:13:01 -07001354int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
1355 struct page *page)
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001356{
1357 if (addr < vma->vm_start || addr >= vma->vm_end)
1358 return -EFAULT;
1359 if (!page_count(page))
1360 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001361 vma->vm_flags |= VM_INSERTPAGE;
Nick Piggin423bad602008-04-28 02:13:01 -07001362 return insert_page(vma, addr, page, vma->vm_page_prot);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001363}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001364EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001365
Nick Piggin423bad602008-04-28 02:13:01 -07001366static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
1367 unsigned long pfn, pgprot_t prot)
1368{
1369 struct mm_struct *mm = vma->vm_mm;
1370 int retval;
1371 pte_t *pte, entry;
1372 spinlock_t *ptl;
1373
1374 retval = -ENOMEM;
1375 pte = get_locked_pte(mm, addr, &ptl);
1376 if (!pte)
1377 goto out;
1378 retval = -EBUSY;
1379 if (!pte_none(*pte))
1380 goto out_unlock;
1381
1382 /* Ok, finally just insert the thing.. */
1383 entry = pte_mkspecial(pfn_pte(pfn, prot));
1384 set_pte_at(mm, addr, pte, entry);
1385 update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
1386
1387 retval = 0;
1388out_unlock:
1389 pte_unmap_unlock(pte, ptl);
1390out:
1391 return retval;
1392}
1393
Nick Piggine0dc0d82007-02-12 00:51:36 -08001394/**
1395 * vm_insert_pfn - insert single pfn into user vma
1396 * @vma: user vma to map to
1397 * @addr: target user address of this page
1398 * @pfn: source kernel pfn
1399 *
1400 * Similar to vm_inert_page, this allows drivers to insert individual pages
1401 * they've allocated into a user vma. Same comments apply.
1402 *
1403 * This function should only be called from a vm_ops->fault handler, and
1404 * in that case the handler should return NULL.
Nick Piggin0d71d10a2008-07-23 21:27:05 -07001405 *
1406 * vma cannot be a COW mapping.
1407 *
1408 * As this is called only for pages that do not currently exist, we
1409 * do not need to flush old virtual caches or the TLB.
Nick Piggine0dc0d82007-02-12 00:51:36 -08001410 */
1411int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
Nick Piggin423bad602008-04-28 02:13:01 -07001412 unsigned long pfn)
Nick Piggine0dc0d82007-02-12 00:51:36 -08001413{
Nick Piggin7e675132008-04-28 02:13:00 -07001414 /*
1415 * Technically, architectures with pte_special can avoid all these
1416 * restrictions (same for remap_pfn_range). However we would like
1417 * consistency in testing and feature parity among all, so we should
1418 * try to keep these invariants in place for everybody.
1419 */
Jared Hulbertb379d792008-04-28 02:12:58 -07001420 BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
1421 BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
1422 (VM_PFNMAP|VM_MIXEDMAP));
1423 BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
1424 BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
Nick Piggine0dc0d82007-02-12 00:51:36 -08001425
Nick Piggin423bad602008-04-28 02:13:01 -07001426 if (addr < vma->vm_start || addr >= vma->vm_end)
1427 return -EFAULT;
1428 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
Nick Piggine0dc0d82007-02-12 00:51:36 -08001429}
1430EXPORT_SYMBOL(vm_insert_pfn);
1431
Nick Piggin423bad602008-04-28 02:13:01 -07001432int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
1433 unsigned long pfn)
1434{
1435 BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
1436
1437 if (addr < vma->vm_start || addr >= vma->vm_end)
1438 return -EFAULT;
1439
1440 /*
1441 * If we don't have pte special, then we have to use the pfn_valid()
1442 * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
1443 * refcount the page if pfn_valid is true (hence insert_page rather
1444 * than insert_pfn).
1445 */
1446 if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
1447 struct page *page;
1448
1449 page = pfn_to_page(pfn);
1450 return insert_page(vma, addr, page, vma->vm_page_prot);
1451 }
1452 return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
1453}
1454EXPORT_SYMBOL(vm_insert_mixed);
1455
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001456/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001457 * maps a range of physical memory into the requested pages. the old
1458 * mappings are removed. any references to nonexistent pages results
1459 * in null mappings (currently treated as "copy-on-access")
1460 */
1461static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1462 unsigned long addr, unsigned long end,
1463 unsigned long pfn, pgprot_t prot)
1464{
1465 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001466 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467
Hugh Dickinsc74df322005-10-29 18:16:23 -07001468 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469 if (!pte)
1470 return -ENOMEM;
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001471 arch_enter_lazy_mmu_mode();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 do {
1473 BUG_ON(!pte_none(*pte));
Nick Piggin7e675132008-04-28 02:13:00 -07001474 set_pte_at(mm, addr, pte, pte_mkspecial(pfn_pte(pfn, prot)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001475 pfn++;
1476 } while (pte++, addr += PAGE_SIZE, addr != end);
Zachary Amsden6606c3e2006-09-30 23:29:33 -07001477 arch_leave_lazy_mmu_mode();
Hugh Dickinsc74df322005-10-29 18:16:23 -07001478 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 return 0;
1480}
1481
1482static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1483 unsigned long addr, unsigned long end,
1484 unsigned long pfn, pgprot_t prot)
1485{
1486 pmd_t *pmd;
1487 unsigned long next;
1488
1489 pfn -= addr >> PAGE_SHIFT;
1490 pmd = pmd_alloc(mm, pud, addr);
1491 if (!pmd)
1492 return -ENOMEM;
1493 do {
1494 next = pmd_addr_end(addr, end);
1495 if (remap_pte_range(mm, pmd, addr, next,
1496 pfn + (addr >> PAGE_SHIFT), prot))
1497 return -ENOMEM;
1498 } while (pmd++, addr = next, addr != end);
1499 return 0;
1500}
1501
1502static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1503 unsigned long addr, unsigned long end,
1504 unsigned long pfn, pgprot_t prot)
1505{
1506 pud_t *pud;
1507 unsigned long next;
1508
1509 pfn -= addr >> PAGE_SHIFT;
1510 pud = pud_alloc(mm, pgd, addr);
1511 if (!pud)
1512 return -ENOMEM;
1513 do {
1514 next = pud_addr_end(addr, end);
1515 if (remap_pmd_range(mm, pud, addr, next,
1516 pfn + (addr >> PAGE_SHIFT), prot))
1517 return -ENOMEM;
1518 } while (pud++, addr = next, addr != end);
1519 return 0;
1520}
1521
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07001522/**
1523 * remap_pfn_range - remap kernel memory to userspace
1524 * @vma: user vma to map to
1525 * @addr: target user address to start at
1526 * @pfn: physical address of kernel memory
1527 * @size: size of map area
1528 * @prot: page protection flags for this mapping
1529 *
1530 * Note: this is only safe if the mm semaphore is held when called.
1531 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001532int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1533 unsigned long pfn, unsigned long size, pgprot_t prot)
1534{
1535 pgd_t *pgd;
1536 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001537 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001538 struct mm_struct *mm = vma->vm_mm;
1539 int err;
1540
1541 /*
1542 * Physically remapped pages are special. Tell the
1543 * rest of the world about it:
1544 * VM_IO tells people not to look at these pages
1545 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001546 * VM_RESERVED is specified all over the place, because
1547 * in 2.4 it kept swapout's vma scan off this vma; but
1548 * in 2.6 the LRU scan won't even find its pages, so this
1549 * flag means no more than count its pages in reserved_vm,
1550 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001551 * VM_PFNMAP tells the core MM that the base pages are just
1552 * raw PFN mappings, and do not have a "struct page" associated
1553 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001554 *
1555 * There's a horrible special case to handle copy-on-write
1556 * behaviour that some programs depend on. We mark the "original"
1557 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558 */
Linus Torvalds67121172005-12-11 20:38:17 -08001559 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001560 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001561 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001562 vma->vm_pgoff = pfn;
1563 }
1564
Linus Torvalds6aab3412005-11-28 14:34:23 -08001565 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001566
1567 BUG_ON(addr >= end);
1568 pfn -= addr >> PAGE_SHIFT;
1569 pgd = pgd_offset(mm, addr);
1570 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 do {
1572 next = pgd_addr_end(addr, end);
1573 err = remap_pud_range(mm, pgd, addr, next,
1574 pfn + (addr >> PAGE_SHIFT), prot);
1575 if (err)
1576 break;
1577 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001578 return err;
1579}
1580EXPORT_SYMBOL(remap_pfn_range);
1581
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001582static int apply_to_pte_range(struct mm_struct *mm, pmd_t *pmd,
1583 unsigned long addr, unsigned long end,
1584 pte_fn_t fn, void *data)
1585{
1586 pte_t *pte;
1587 int err;
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001588 pgtable_t token;
Borislav Petkov94909912007-05-06 14:49:17 -07001589 spinlock_t *uninitialized_var(ptl);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001590
1591 pte = (mm == &init_mm) ?
1592 pte_alloc_kernel(pmd, addr) :
1593 pte_alloc_map_lock(mm, pmd, addr, &ptl);
1594 if (!pte)
1595 return -ENOMEM;
1596
1597 BUG_ON(pmd_huge(*pmd));
1598
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001599 token = pmd_pgtable(*pmd);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001600
1601 do {
Martin Schwidefsky2f569af2008-02-08 04:22:04 -08001602 err = fn(pte, token, addr, data);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001603 if (err)
1604 break;
1605 } while (pte++, addr += PAGE_SIZE, addr != end);
1606
1607 if (mm != &init_mm)
1608 pte_unmap_unlock(pte-1, ptl);
1609 return err;
1610}
1611
1612static int apply_to_pmd_range(struct mm_struct *mm, pud_t *pud,
1613 unsigned long addr, unsigned long end,
1614 pte_fn_t fn, void *data)
1615{
1616 pmd_t *pmd;
1617 unsigned long next;
1618 int err;
1619
Andi Kleenceb86872008-07-23 21:27:50 -07001620 BUG_ON(pud_huge(*pud));
1621
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001622 pmd = pmd_alloc(mm, pud, addr);
1623 if (!pmd)
1624 return -ENOMEM;
1625 do {
1626 next = pmd_addr_end(addr, end);
1627 err = apply_to_pte_range(mm, pmd, addr, next, fn, data);
1628 if (err)
1629 break;
1630 } while (pmd++, addr = next, addr != end);
1631 return err;
1632}
1633
1634static int apply_to_pud_range(struct mm_struct *mm, pgd_t *pgd,
1635 unsigned long addr, unsigned long end,
1636 pte_fn_t fn, void *data)
1637{
1638 pud_t *pud;
1639 unsigned long next;
1640 int err;
1641
1642 pud = pud_alloc(mm, pgd, addr);
1643 if (!pud)
1644 return -ENOMEM;
1645 do {
1646 next = pud_addr_end(addr, end);
1647 err = apply_to_pmd_range(mm, pud, addr, next, fn, data);
1648 if (err)
1649 break;
1650 } while (pud++, addr = next, addr != end);
1651 return err;
1652}
1653
1654/*
1655 * Scan a region of virtual memory, filling in page tables as necessary
1656 * and calling a provided function on each leaf page table.
1657 */
1658int apply_to_page_range(struct mm_struct *mm, unsigned long addr,
1659 unsigned long size, pte_fn_t fn, void *data)
1660{
1661 pgd_t *pgd;
1662 unsigned long next;
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001663 unsigned long start = addr, end = addr + size;
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001664 int err;
1665
1666 BUG_ON(addr >= end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001667 mmu_notifier_invalidate_range_start(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001668 pgd = pgd_offset(mm, addr);
1669 do {
1670 next = pgd_addr_end(addr, end);
1671 err = apply_to_pud_range(mm, pgd, addr, next, fn, data);
1672 if (err)
1673 break;
1674 } while (pgd++, addr = next, addr != end);
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001675 mmu_notifier_invalidate_range_end(mm, start, end);
Jeremy Fitzhardingeaee16b32007-05-06 14:48:54 -07001676 return err;
1677}
1678EXPORT_SYMBOL_GPL(apply_to_page_range);
1679
Linus Torvalds1da177e2005-04-16 15:20:36 -07001680/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001681 * handle_pte_fault chooses page fault handler according to an entry
1682 * which was read non-atomically. Before making any commitment, on
1683 * those architectures or configurations (e.g. i386 with PAE) which
1684 * might give a mix of unmatched parts, do_swap_page and do_file_page
1685 * must check under lock before unmapping the pte and proceeding
1686 * (but do_wp_page is only called after already making such a check;
1687 * and do_anonymous_page and do_no_page can safely check later on).
1688 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001689static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001690 pte_t *page_table, pte_t orig_pte)
1691{
1692 int same = 1;
1693#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1694 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001695 spinlock_t *ptl = pte_lockptr(mm, pmd);
1696 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001697 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001698 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001699 }
1700#endif
1701 pte_unmap(page_table);
1702 return same;
1703}
1704
1705/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1707 * servicing faults for write access. In the normal case, do always want
1708 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1709 * that do not have writing enabled, when used by access_process_vm.
1710 */
1711static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1712{
1713 if (likely(vma->vm_flags & VM_WRITE))
1714 pte = pte_mkwrite(pte);
1715 return pte;
1716}
1717
Atsushi Nemoto9de455b2006-12-12 17:14:55 +00001718static 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 -08001719{
1720 /*
1721 * If the source page was a PFN mapping, we don't have
1722 * a "struct page" for it. We do a best-effort copy by
1723 * just copying from the original user address. If that
1724 * fails, we just zero-fill it. Live with it.
1725 */
1726 if (unlikely(!src)) {
1727 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2dbbc2005-11-29 14:07:55 -08001728 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1729
1730 /*
1731 * This really shouldn't fail, because the page is there
1732 * in the page tables. But it might just be unreadable,
1733 * in which case we just give up and fill the result with
1734 * zeroes.
1735 */
1736 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001737 memset(kaddr, 0, PAGE_SIZE);
1738 kunmap_atomic(kaddr, KM_USER0);
Dmitriy Monakhovc4ec7b02006-10-19 23:29:08 -07001739 flush_dcache_page(dst);
Nick Piggin0ed361d2008-02-04 22:29:34 -08001740 } else
1741 copy_user_highpage(dst, src, va, vma);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001742}
1743
Linus Torvalds1da177e2005-04-16 15:20:36 -07001744/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001745 * This routine handles present pages, when users try to write
1746 * to a shared page. It is done by copying the page to a new address
1747 * and decrementing the shared-page counter for the old page.
1748 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001749 * Note that this routine assumes that the protection checks have been
1750 * done by the caller (the low-level page fault routine in most cases).
1751 * Thus we can safely just mark it writable once we've done any necessary
1752 * COW.
1753 *
1754 * We also mark the page dirty at this point even though the page will
1755 * change only once the write actually happens. This avoids a few races,
1756 * and potentially makes it more efficient.
1757 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001758 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1759 * but allow concurrent faults), with pte both mapped and locked.
1760 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001761 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001762static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1763 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001764 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001765{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001766 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001767 pte_t entry;
Nick Piggin83c54072007-07-19 01:47:05 -07001768 int reuse = 0, ret = 0;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02001769 int page_mkwrite = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001770 struct page *dirty_page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001771
Linus Torvalds6aab3412005-11-28 14:34:23 -08001772 old_page = vm_normal_page(vma, address, orig_pte);
Peter Zijlstra251b97f2008-07-04 09:59:24 -07001773 if (!old_page) {
1774 /*
1775 * VM_MIXEDMAP !pfn_valid() case
1776 *
1777 * We should not cow pages in a shared writeable mapping.
1778 * Just mark the pages writable as we can't do any dirty
1779 * accounting on raw pfn maps.
1780 */
1781 if ((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
1782 (VM_WRITE|VM_SHARED))
1783 goto reuse;
Linus Torvalds6aab3412005-11-28 14:34:23 -08001784 goto gotten;
Peter Zijlstra251b97f2008-07-04 09:59:24 -07001785 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001786
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001787 /*
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001788 * Take out anonymous pages first, anonymous shared vmas are
1789 * not dirty accountable.
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001790 */
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001791 if (PageAnon(old_page)) {
Nick Piggin529ae9a2008-08-02 12:01:03 +02001792 if (trylock_page(old_page)) {
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001793 reuse = can_share_swap_page(old_page);
1794 unlock_page(old_page);
1795 }
1796 } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001797 (VM_WRITE|VM_SHARED))) {
Peter Zijlstraee6a6452006-09-25 23:31:00 -07001798 /*
1799 * Only catch write-faults on shared writable pages,
1800 * read-only shared pages can get COWed by
1801 * get_user_pages(.write=1, .force=1).
1802 */
David Howells9637a5e2006-06-23 02:03:43 -07001803 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
1804 /*
1805 * Notify the address space that the page is about to
1806 * become writable so that it can prohibit this or wait
1807 * for the page to get into an appropriate state.
1808 *
1809 * We do this without the lock held, so that it can
1810 * sleep if it needs to.
1811 */
1812 page_cache_get(old_page);
1813 pte_unmap_unlock(page_table, ptl);
1814
1815 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
1816 goto unwritable_page;
1817
David Howells9637a5e2006-06-23 02:03:43 -07001818 /*
1819 * Since we dropped the lock we need to revalidate
1820 * the PTE as someone else may have changed it. If
1821 * they did, we just return, as we can count on the
1822 * MMU to tell us if they didn't also make it writable.
1823 */
1824 page_table = pte_offset_map_lock(mm, pmd, address,
1825 &ptl);
Hugh Dickinsc3704ce2007-02-10 01:43:00 -08001826 page_cache_release(old_page);
David Howells9637a5e2006-06-23 02:03:43 -07001827 if (!pte_same(*page_table, orig_pte))
1828 goto unlock;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02001829
1830 page_mkwrite = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 }
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001832 dirty_page = old_page;
1833 get_page(dirty_page);
David Howells9637a5e2006-06-23 02:03:43 -07001834 reuse = 1;
David Howells9637a5e2006-06-23 02:03:43 -07001835 }
1836
1837 if (reuse) {
Peter Zijlstra251b97f2008-07-04 09:59:24 -07001838reuse:
David Howells9637a5e2006-06-23 02:03:43 -07001839 flush_cache_page(vma, address, pte_pfn(orig_pte));
1840 entry = pte_mkyoung(orig_pte);
1841 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
KAMEZAWA Hiroyuki954ffcb2007-10-16 01:25:44 -07001842 if (ptep_set_access_flags(vma, address, page_table, entry,1))
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07001843 update_mmu_cache(vma, address, entry);
David Howells9637a5e2006-06-23 02:03:43 -07001844 ret |= VM_FAULT_WRITE;
1845 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001846 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001847
1848 /*
1849 * Ok, we need to copy. Oh, well..
1850 */
Nick Pigginb5810032005-10-29 18:16:12 -07001851 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001852gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001853 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854
1855 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001856 goto oom;
Nick Piggin557ed1f2007-10-16 01:24:40 -07001857 VM_BUG_ON(old_page == ZERO_PAGE(0));
1858 new_page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
1859 if (!new_page)
1860 goto oom;
1861 cow_user_page(new_page, old_page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08001862 __SetPageUptodate(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001863
Balbir Singhe1a1cd52008-02-07 00:14:02 -08001864 if (mem_cgroup_charge(new_page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001865 goto oom_free_new;
1866
Linus Torvalds1da177e2005-04-16 15:20:36 -07001867 /*
1868 * Re-check the pte - we dropped the lock
1869 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001870 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001871 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001872 if (old_page) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001873 if (!PageAnon(old_page)) {
1874 dec_mm_counter(mm, file_rss);
1875 inc_mm_counter(mm, anon_rss);
1876 }
1877 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001878 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001879 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001880 entry = mk_pte(new_page, vma->vm_page_prot);
1881 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Siddha, Suresh B4ce072f2006-09-29 01:58:42 -07001882 /*
1883 * Clear the pte entry and flush it first, before updating the
1884 * pte with the new entry. This will avoid a race condition
1885 * seen in the presence of one thread doing SMC and another
1886 * thread doing COW.
1887 */
Andrea Arcangelicddb8a52008-07-28 15:46:29 -07001888 ptep_clear_flush_notify(vma, address, page_table);
Siddha, Suresh B4ce072f2006-09-29 01:58:42 -07001889 set_pte_at(mm, address, page_table, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001890 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001891 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08001892 page_add_new_anon_rmap(new_page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893
Nick Piggin945754a2008-06-23 14:30:30 +02001894 if (old_page) {
1895 /*
1896 * Only after switching the pte to the new page may
1897 * we remove the mapcount here. Otherwise another
1898 * process may come and find the rmap count decremented
1899 * before the pte is switched to the new page, and
1900 * "reuse" the old page writing into it while our pte
1901 * here still points into it and can be read by other
1902 * threads.
1903 *
1904 * The critical issue is to order this
1905 * page_remove_rmap with the ptp_clear_flush above.
1906 * Those stores are ordered by (if nothing else,)
1907 * the barrier present in the atomic_add_negative
1908 * in page_remove_rmap.
1909 *
1910 * Then the TLB flush in ptep_clear_flush ensures that
1911 * no process can access the old page before the
1912 * decremented mapcount is visible. And the old page
1913 * cannot be reused until after the decremented
1914 * mapcount is visible. So transitively, TLBs to
1915 * old page will be flushed before it can be reused.
1916 */
1917 page_remove_rmap(old_page, vma);
1918 }
1919
Linus Torvalds1da177e2005-04-16 15:20:36 -07001920 /* Free the old page.. */
1921 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001922 ret |= VM_FAULT_WRITE;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001923 } else
1924 mem_cgroup_uncharge_page(new_page);
1925
Hugh Dickins920fc352005-11-21 21:32:17 -08001926 if (new_page)
1927 page_cache_release(new_page);
1928 if (old_page)
1929 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001930unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001931 pte_unmap_unlock(page_table, ptl);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001932 if (dirty_page) {
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03001933 if (vma->vm_file)
1934 file_update_time(vma->vm_file);
1935
Nick Piggin79352892007-07-19 01:47:22 -07001936 /*
1937 * Yes, Virginia, this is actually required to prevent a race
1938 * with clear_page_dirty_for_io() from clearing the page dirty
1939 * bit after it clear all dirty ptes, but before a racing
1940 * do_wp_page installs a dirty pte.
1941 *
1942 * do_no_page is protected similarly.
1943 */
1944 wait_on_page_locked(dirty_page);
Peter Zijlstraa200ee12007-10-08 18:54:37 +02001945 set_page_dirty_balance(dirty_page, page_mkwrite);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07001946 put_page(dirty_page);
1947 }
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001948 return ret;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08001949oom_free_new:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08001950 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001951oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001952 if (old_page)
1953 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001954 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07001955
1956unwritable_page:
1957 page_cache_release(old_page);
1958 return VM_FAULT_SIGBUS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001959}
1960
1961/*
1962 * Helper functions for unmap_mapping_range().
1963 *
1964 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1965 *
1966 * We have to restart searching the prio_tree whenever we drop the lock,
1967 * since the iterator is only valid while the lock is held, and anyway
1968 * a later vma might be split and reinserted earlier while lock dropped.
1969 *
1970 * The list of nonlinear vmas could be handled more efficiently, using
1971 * a placeholder, but handle it in the same way until a need is shown.
1972 * It is important to search the prio_tree before nonlinear list: a vma
1973 * may become nonlinear and be shifted from prio_tree to nonlinear list
1974 * while the lock is dropped; but never shifted from list to prio_tree.
1975 *
1976 * In order to make forward progress despite restarting the search,
1977 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1978 * quickly skip it next time around. Since the prio_tree search only
1979 * shows us those vmas affected by unmapping the range in question, we
1980 * can't efficiently keep all vmas in step with mapping->truncate_count:
1981 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1982 * mapping->truncate_count and vma->vm_truncate_count are protected by
1983 * i_mmap_lock.
1984 *
1985 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001986 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001987 * and restart from that address when we reach that vma again. It might
1988 * have been split or merged, shrunk or extended, but never shifted: so
1989 * restart_addr remains valid so long as it remains in the vma's range.
1990 * unmap_mapping_range forces truncate_count to leap over page-aligned
1991 * values so we can save vma's restart_addr in its truncate_count field.
1992 */
1993#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1994
1995static void reset_vma_truncate_counts(struct address_space *mapping)
1996{
1997 struct vm_area_struct *vma;
1998 struct prio_tree_iter iter;
1999
2000 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
2001 vma->vm_truncate_count = 0;
2002 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
2003 vma->vm_truncate_count = 0;
2004}
2005
2006static int unmap_mapping_range_vma(struct vm_area_struct *vma,
2007 unsigned long start_addr, unsigned long end_addr,
2008 struct zap_details *details)
2009{
2010 unsigned long restart_addr;
2011 int need_break;
2012
Nick Piggind00806b2007-07-19 01:46:57 -07002013 /*
2014 * files that support invalidating or truncating portions of the
Nick Piggind0217ac2007-07-19 01:47:03 -07002015 * file from under mmaped areas must have their ->fault function
Nick Piggin83c54072007-07-19 01:47:05 -07002016 * return a locked page (and set VM_FAULT_LOCKED in the return).
2017 * This provides synchronisation against concurrent unmapping here.
Nick Piggind00806b2007-07-19 01:46:57 -07002018 */
Nick Piggind00806b2007-07-19 01:46:57 -07002019
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020again:
2021 restart_addr = vma->vm_truncate_count;
2022 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
2023 start_addr = restart_addr;
2024 if (start_addr >= end_addr) {
2025 /* Top of vma has been split off since last time */
2026 vma->vm_truncate_count = details->truncate_count;
2027 return 0;
2028 }
2029 }
2030
Hugh Dickinsee39b372005-04-19 13:29:15 -07002031 restart_addr = zap_page_range(vma, start_addr,
2032 end_addr - start_addr, details);
Nick Piggin95c354f2008-01-30 13:31:20 +01002033 need_break = need_resched() || spin_needbreak(details->i_mmap_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002034
Hugh Dickinsee39b372005-04-19 13:29:15 -07002035 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036 /* We have now completed this vma: mark it so */
2037 vma->vm_truncate_count = details->truncate_count;
2038 if (!need_break)
2039 return 0;
2040 } else {
2041 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07002042 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043 if (!need_break)
2044 goto again;
2045 }
2046
2047 spin_unlock(details->i_mmap_lock);
2048 cond_resched();
2049 spin_lock(details->i_mmap_lock);
2050 return -EINTR;
2051}
2052
2053static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
2054 struct zap_details *details)
2055{
2056 struct vm_area_struct *vma;
2057 struct prio_tree_iter iter;
2058 pgoff_t vba, vea, zba, zea;
2059
2060restart:
2061 vma_prio_tree_foreach(vma, &iter, root,
2062 details->first_index, details->last_index) {
2063 /* Skip quickly over those we have already dealt with */
2064 if (vma->vm_truncate_count == details->truncate_count)
2065 continue;
2066
2067 vba = vma->vm_pgoff;
2068 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
2069 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
2070 zba = details->first_index;
2071 if (zba < vba)
2072 zba = vba;
2073 zea = details->last_index;
2074 if (zea > vea)
2075 zea = vea;
2076
2077 if (unmap_mapping_range_vma(vma,
2078 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
2079 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
2080 details) < 0)
2081 goto restart;
2082 }
2083}
2084
2085static inline void unmap_mapping_range_list(struct list_head *head,
2086 struct zap_details *details)
2087{
2088 struct vm_area_struct *vma;
2089
2090 /*
2091 * In nonlinear VMAs there is no correspondence between virtual address
2092 * offset and file offset. So we must perform an exhaustive search
2093 * across *all* the pages in each nonlinear VMA, not just the pages
2094 * whose virtual address lies outside the file truncation point.
2095 */
2096restart:
2097 list_for_each_entry(vma, head, shared.vm_set.list) {
2098 /* Skip quickly over those we have already dealt with */
2099 if (vma->vm_truncate_count == details->truncate_count)
2100 continue;
2101 details->nonlinear_vma = vma;
2102 if (unmap_mapping_range_vma(vma, vma->vm_start,
2103 vma->vm_end, details) < 0)
2104 goto restart;
2105 }
2106}
2107
2108/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08002109 * 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 -07002110 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 * @holebegin: byte in first page to unmap, relative to the start of
2112 * the underlying file. This will be rounded down to a PAGE_SIZE
2113 * boundary. Note that this is different from vmtruncate(), which
2114 * must keep the partial page. In contrast, we must get rid of
2115 * partial pages.
2116 * @holelen: size of prospective hole in bytes. This will be rounded
2117 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
2118 * end of the file.
2119 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
2120 * but 0 when invalidating pagecache, don't throw away private data.
2121 */
2122void unmap_mapping_range(struct address_space *mapping,
2123 loff_t const holebegin, loff_t const holelen, int even_cows)
2124{
2125 struct zap_details details;
2126 pgoff_t hba = holebegin >> PAGE_SHIFT;
2127 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2128
2129 /* Check for overflow. */
2130 if (sizeof(holelen) > sizeof(hlen)) {
2131 long long holeend =
2132 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
2133 if (holeend & ~(long long)ULONG_MAX)
2134 hlen = ULONG_MAX - hba + 1;
2135 }
2136
2137 details.check_mapping = even_cows? NULL: mapping;
2138 details.nonlinear_vma = NULL;
2139 details.first_index = hba;
2140 details.last_index = hba + hlen - 1;
2141 if (details.last_index < details.first_index)
2142 details.last_index = ULONG_MAX;
2143 details.i_mmap_lock = &mapping->i_mmap_lock;
2144
2145 spin_lock(&mapping->i_mmap_lock);
2146
Nick Piggind00806b2007-07-19 01:46:57 -07002147 /* Protect against endless unmapping loops */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148 mapping->truncate_count++;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002149 if (unlikely(is_restart_addr(mapping->truncate_count))) {
2150 if (mapping->truncate_count == 0)
2151 reset_vma_truncate_counts(mapping);
2152 mapping->truncate_count++;
2153 }
2154 details.truncate_count = mapping->truncate_count;
2155
2156 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
2157 unmap_mapping_range_tree(&mapping->i_mmap, &details);
2158 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
2159 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
2160 spin_unlock(&mapping->i_mmap_lock);
2161}
2162EXPORT_SYMBOL(unmap_mapping_range);
2163
Rolf Eike Beerbfa5bf62006-09-25 23:31:22 -07002164/**
2165 * vmtruncate - unmap mappings "freed" by truncate() syscall
2166 * @inode: inode of the file used
2167 * @offset: file offset to start truncating
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168 *
2169 * NOTE! We have to be ready to update the memory sharing
2170 * between the file and the memory map for a potential last
2171 * incomplete page. Ugly, but necessary.
2172 */
2173int vmtruncate(struct inode * inode, loff_t offset)
2174{
Christoph Hellwig61d50482008-02-04 22:28:56 -08002175 if (inode->i_size < offset) {
2176 unsigned long limit;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177
Christoph Hellwig61d50482008-02-04 22:28:56 -08002178 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
2179 if (limit != RLIM_INFINITY && offset > limit)
2180 goto out_sig;
2181 if (offset > inode->i_sb->s_maxbytes)
2182 goto out_big;
2183 i_size_write(inode, offset);
2184 } else {
2185 struct address_space *mapping = inode->i_mapping;
Nick Piggind00806b2007-07-19 01:46:57 -07002186
Christoph Hellwig61d50482008-02-04 22:28:56 -08002187 /*
2188 * truncation of in-use swapfiles is disallowed - it would
2189 * cause subsequent swapout to scribble on the now-freed
2190 * blocks.
2191 */
2192 if (IS_SWAPFILE(inode))
2193 return -ETXTBSY;
2194 i_size_write(inode, offset);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002195
Christoph Hellwig61d50482008-02-04 22:28:56 -08002196 /*
2197 * unmap_mapping_range is called twice, first simply for
2198 * efficiency so that truncate_inode_pages does fewer
2199 * single-page unmaps. However after this first call, and
2200 * before truncate_inode_pages finishes, it is possible for
2201 * private pages to be COWed, which remain after
2202 * truncate_inode_pages finishes, hence the second
2203 * unmap_mapping_range call must be made for correctness.
2204 */
2205 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2206 truncate_inode_pages(mapping, offset);
2207 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
2208 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002209
Linus Torvalds1da177e2005-04-16 15:20:36 -07002210 if (inode->i_op && inode->i_op->truncate)
2211 inode->i_op->truncate(inode);
2212 return 0;
Christoph Hellwig61d50482008-02-04 22:28:56 -08002213
Linus Torvalds1da177e2005-04-16 15:20:36 -07002214out_sig:
2215 send_sig(SIGXFSZ, current, 0);
2216out_big:
2217 return -EFBIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002218}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002219EXPORT_SYMBOL(vmtruncate);
2220
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002221int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
2222{
2223 struct address_space *mapping = inode->i_mapping;
2224
2225 /*
2226 * If the underlying filesystem is not going to provide
2227 * a way to truncate a range of blocks (punch a hole) -
2228 * we should return failure right now.
2229 */
2230 if (!inode->i_op || !inode->i_op->truncate_range)
2231 return -ENOSYS;
2232
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002233 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002234 down_write(&inode->i_alloc_sem);
2235 unmap_mapping_range(mapping, offset, (end - offset), 1);
2236 truncate_inode_pages_range(mapping, offset, end);
Nick Piggind00806b2007-07-19 01:46:57 -07002237 unmap_mapping_range(mapping, offset, (end - offset), 1);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002238 inode->i_op->truncate_range(inode, offset, end);
2239 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08002240 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002241
2242 return 0;
2243}
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08002244
Linus Torvalds1da177e2005-04-16 15:20:36 -07002245/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002246 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2247 * but allow concurrent faults), and pte mapped but not yet locked.
2248 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002249 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002250static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
2251 unsigned long address, pte_t *page_table, pmd_t *pmd,
2252 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002254 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002255 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07002256 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002257 pte_t pte;
Nick Piggin83c54072007-07-19 01:47:05 -07002258 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002259
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002260 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002261 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07002262
2263 entry = pte_to_swp_entry(orig_pte);
Christoph Lameter06972122006-06-23 02:03:35 -07002264 if (is_migration_entry(entry)) {
2265 migration_entry_wait(mm, pmd, address);
2266 goto out;
2267 }
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002268 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002269 page = lookup_swap_cache(entry);
2270 if (!page) {
Ashwin Chaugule098fe652006-12-06 20:31:54 -08002271 grab_swap_token(); /* Contend for token _before_ read-in */
Hugh Dickins02098fe2008-02-04 22:28:42 -08002272 page = swapin_readahead(entry,
2273 GFP_HIGHUSER_MOVABLE, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002274 if (!page) {
2275 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002276 * Back out if somebody else faulted in this pte
2277 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002278 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002279 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002280 if (likely(pte_same(*page_table, orig_pte)))
2281 ret = VM_FAULT_OOM;
Shailabh Nagar0ff92242006-07-14 00:24:37 -07002282 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Hugh Dickins65500d22005-10-29 18:15:59 -07002283 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002284 }
2285
2286 /* Had to read the page from swap area: Major fault */
2287 ret = VM_FAULT_MAJOR;
Christoph Lameterf8891e52006-06-30 01:55:45 -07002288 count_vm_event(PGMAJFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289 }
2290
Balbir Singhe1a1cd52008-02-07 00:14:02 -08002291 if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002292 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
2293 ret = VM_FAULT_OOM;
2294 goto out;
2295 }
2296
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297 mark_page_accessed(page);
2298 lock_page(page);
Balbir Singh20a10222007-11-14 17:00:33 -08002299 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300
2301 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002302 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002303 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002304 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07002305 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07002306 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002307
2308 if (unlikely(!PageUptodate(page))) {
2309 ret = VM_FAULT_SIGBUS;
2310 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002311 }
2312
2313 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002314
Hugh Dickins42946212005-10-29 18:16:05 -07002315 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002316 pte = mk_pte(page, vma->vm_page_prot);
2317 if (write_access && can_share_swap_page(page)) {
2318 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
2319 write_access = 0;
2320 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002321
2322 flush_icache_page(vma, page);
2323 set_pte_at(mm, address, page_table, pte);
2324 page_add_anon_rmap(page, vma, address);
2325
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07002326 swap_free(entry);
2327 if (vm_swap_full())
2328 remove_exclusive_swap_page(page);
2329 unlock_page(page);
2330
Linus Torvalds1da177e2005-04-16 15:20:36 -07002331 if (write_access) {
Hugh Dickins61469f12008-03-04 14:29:04 -08002332 ret |= do_wp_page(mm, vma, address, page_table, pmd, ptl, pte);
2333 if (ret & VM_FAULT_ERROR)
2334 ret &= VM_FAULT_ERROR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002335 goto out;
2336 }
2337
2338 /* No need to invalidate - it was non-present before */
2339 update_mmu_cache(vma, address, pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07002340unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002341 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002342out:
2343 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002344out_nomap:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002345 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002346 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07002347 unlock_page(page);
2348 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002349 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350}
2351
2352/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002353 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2354 * but allow concurrent faults), and pte mapped but not yet locked.
2355 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002357static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2358 unsigned long address, pte_t *page_table, pmd_t *pmd,
2359 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002360{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002361 struct page *page;
2362 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002363 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002364
Nick Piggin557ed1f2007-10-16 01:24:40 -07002365 /* Allocate our own private page. */
2366 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002367
Nick Piggin557ed1f2007-10-16 01:24:40 -07002368 if (unlikely(anon_vma_prepare(vma)))
2369 goto oom;
2370 page = alloc_zeroed_user_highpage_movable(vma, address);
2371 if (!page)
2372 goto oom;
Nick Piggin0ed361d2008-02-04 22:29:34 -08002373 __SetPageUptodate(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374
Balbir Singhe1a1cd52008-02-07 00:14:02 -08002375 if (mem_cgroup_charge(page, mm, GFP_KERNEL))
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002376 goto oom_free_page;
2377
Nick Piggin557ed1f2007-10-16 01:24:40 -07002378 entry = mk_pte(page, vma->vm_page_prot);
2379 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002380
Nick Piggin557ed1f2007-10-16 01:24:40 -07002381 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2382 if (!pte_none(*page_table))
2383 goto release;
2384 inc_mm_counter(mm, anon_rss);
2385 lru_cache_add_active(page);
2386 page_add_new_anon_rmap(page, vma, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002387 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002388
2389 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002390 update_mmu_cache(vma, address, entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002391unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002392 pte_unmap_unlock(page_table, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002393 return 0;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002394release:
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002395 mem_cgroup_uncharge_page(page);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002396 page_cache_release(page);
2397 goto unlock;
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002398oom_free_page:
Hugh Dickins6dbf6d32008-03-04 14:29:04 -08002399 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002400oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002401 return VM_FAULT_OOM;
2402}
2403
2404/*
Nick Piggin54cb8822007-07-19 01:46:59 -07002405 * __do_fault() tries to create a new page mapping. It aggressively
Linus Torvalds1da177e2005-04-16 15:20:36 -07002406 * tries to share with existing pages, but makes a separate copy if
Nick Piggin54cb8822007-07-19 01:46:59 -07002407 * the FAULT_FLAG_WRITE is set in the flags parameter in order to avoid
2408 * the next page fault.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409 *
2410 * As this is called only for pages that do not currently exist, we
2411 * do not need to flush old virtual caches or the TLB.
2412 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002413 * We enter with non-exclusive mmap_sem (to exclude vma changes,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002414 * but allow concurrent faults), and pte neither mapped nor locked.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002415 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002416 */
Nick Piggin54cb8822007-07-19 01:46:59 -07002417static int __do_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins16abfa02007-10-04 16:56:06 +01002418 unsigned long address, pmd_t *pmd,
Nick Piggin54cb8822007-07-19 01:46:59 -07002419 pgoff_t pgoff, unsigned int flags, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002420{
Hugh Dickins16abfa02007-10-04 16:56:06 +01002421 pte_t *page_table;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002422 spinlock_t *ptl;
Nick Piggind0217ac2007-07-19 01:47:03 -07002423 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002425 int anon = 0;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002426 struct page *dirty_page = NULL;
Nick Piggind0217ac2007-07-19 01:47:03 -07002427 struct vm_fault vmf;
2428 int ret;
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002429 int page_mkwrite = 0;
Nick Piggin54cb8822007-07-19 01:46:59 -07002430
Nick Piggind0217ac2007-07-19 01:47:03 -07002431 vmf.virtual_address = (void __user *)(address & PAGE_MASK);
2432 vmf.pgoff = pgoff;
2433 vmf.flags = flags;
2434 vmf.page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002435
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002436 ret = vma->vm_ops->fault(vma, &vmf);
2437 if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE)))
2438 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002439
Nick Piggind00806b2007-07-19 01:46:57 -07002440 /*
Nick Piggind0217ac2007-07-19 01:47:03 -07002441 * For consistency in subsequent calls, make the faulted page always
Nick Piggind00806b2007-07-19 01:46:57 -07002442 * locked.
2443 */
Nick Piggin83c54072007-07-19 01:47:05 -07002444 if (unlikely(!(ret & VM_FAULT_LOCKED)))
Nick Piggind0217ac2007-07-19 01:47:03 -07002445 lock_page(vmf.page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002446 else
Nick Piggind0217ac2007-07-19 01:47:03 -07002447 VM_BUG_ON(!PageLocked(vmf.page));
Nick Piggind00806b2007-07-19 01:46:57 -07002448
Linus Torvalds1da177e2005-04-16 15:20:36 -07002449 /*
2450 * Should we do an early C-O-W break?
2451 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002452 page = vmf.page;
Nick Piggin54cb8822007-07-19 01:46:59 -07002453 if (flags & FAULT_FLAG_WRITE) {
David Howells9637a5e2006-06-23 02:03:43 -07002454 if (!(vma->vm_flags & VM_SHARED)) {
Nick Piggin54cb8822007-07-19 01:46:59 -07002455 anon = 1;
Nick Piggind00806b2007-07-19 01:46:57 -07002456 if (unlikely(anon_vma_prepare(vma))) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002457 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002458 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002459 }
Nick Piggin83c54072007-07-19 01:47:05 -07002460 page = alloc_page_vma(GFP_HIGHUSER_MOVABLE,
2461 vma, address);
Nick Piggind00806b2007-07-19 01:46:57 -07002462 if (!page) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002463 ret = VM_FAULT_OOM;
Nick Piggin54cb8822007-07-19 01:46:59 -07002464 goto out;
Nick Piggind00806b2007-07-19 01:46:57 -07002465 }
Nick Piggind0217ac2007-07-19 01:47:03 -07002466 copy_user_highpage(page, vmf.page, address, vma);
Nick Piggin0ed361d2008-02-04 22:29:34 -08002467 __SetPageUptodate(page);
David Howells9637a5e2006-06-23 02:03:43 -07002468 } else {
Nick Piggin54cb8822007-07-19 01:46:59 -07002469 /*
2470 * If the page will be shareable, see if the backing
David Howells9637a5e2006-06-23 02:03:43 -07002471 * address space wants to know that the page is about
Nick Piggin54cb8822007-07-19 01:46:59 -07002472 * to become writable
2473 */
Mark Fasheh69676142007-07-19 01:47:00 -07002474 if (vma->vm_ops->page_mkwrite) {
2475 unlock_page(page);
2476 if (vma->vm_ops->page_mkwrite(vma, page) < 0) {
Nick Piggind0217ac2007-07-19 01:47:03 -07002477 ret = VM_FAULT_SIGBUS;
2478 anon = 1; /* no anon but release vmf.page */
Mark Fasheh69676142007-07-19 01:47:00 -07002479 goto out_unlocked;
2480 }
2481 lock_page(page);
Nick Piggind0217ac2007-07-19 01:47:03 -07002482 /*
2483 * XXX: this is not quite right (racy vs
2484 * invalidate) to unlock and relock the page
2485 * like this, however a better fix requires
2486 * reworking page_mkwrite locking API, which
2487 * is better done later.
2488 */
2489 if (!page->mapping) {
Nick Piggin83c54072007-07-19 01:47:05 -07002490 ret = 0;
Nick Piggind0217ac2007-07-19 01:47:03 -07002491 anon = 1; /* no anon but release vmf.page */
2492 goto out;
2493 }
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002494 page_mkwrite = 1;
David Howells9637a5e2006-06-23 02:03:43 -07002495 }
2496 }
Nick Piggin54cb8822007-07-19 01:46:59 -07002497
Linus Torvalds1da177e2005-04-16 15:20:36 -07002498 }
2499
Balbir Singhe1a1cd52008-02-07 00:14:02 -08002500 if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002501 ret = VM_FAULT_OOM;
2502 goto out;
2503 }
2504
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002505 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002506
2507 /*
2508 * This silly early PAGE_DIRTY setting removes a race
2509 * due to the bad i386 page protection. But it's valid
2510 * for other architectures too.
2511 *
2512 * Note that if write_access is true, we either now have
2513 * an exclusive copy of the page, or this is a shared mapping,
2514 * so we can make it writable and dirty to avoid having to
2515 * handle that later.
2516 */
2517 /* Only go through if we didn't race with anybody else... */
Nick Piggin54cb8822007-07-19 01:46:59 -07002518 if (likely(pte_same(*page_table, orig_pte))) {
Nick Piggind00806b2007-07-19 01:46:57 -07002519 flush_icache_page(vma, page);
2520 entry = mk_pte(page, vma->vm_page_prot);
Nick Piggin54cb8822007-07-19 01:46:59 -07002521 if (flags & FAULT_FLAG_WRITE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002522 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2523 set_pte_at(mm, address, page_table, entry);
2524 if (anon) {
Nick Piggind00806b2007-07-19 01:46:57 -07002525 inc_mm_counter(mm, anon_rss);
2526 lru_cache_add_active(page);
2527 page_add_new_anon_rmap(page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002528 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002529 inc_mm_counter(mm, file_rss);
Nick Piggind00806b2007-07-19 01:46:57 -07002530 page_add_file_rmap(page);
Nick Piggin54cb8822007-07-19 01:46:59 -07002531 if (flags & FAULT_FLAG_WRITE) {
Nick Piggind00806b2007-07-19 01:46:57 -07002532 dirty_page = page;
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002533 get_page(dirty_page);
2534 }
Hugh Dickins42946212005-10-29 18:16:05 -07002535 }
Nick Piggind00806b2007-07-19 01:46:57 -07002536
2537 /* no need to invalidate: a not-present page won't be cached */
2538 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002539 } else {
Balbir Singh8a9f3cc2008-02-07 00:13:53 -08002540 mem_cgroup_uncharge_page(page);
Nick Piggind00806b2007-07-19 01:46:57 -07002541 if (anon)
2542 page_cache_release(page);
2543 else
Nick Piggin54cb8822007-07-19 01:46:59 -07002544 anon = 1; /* no anon but release faulted_page */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002545 }
2546
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002547 pte_unmap_unlock(page_table, ptl);
Nick Piggind00806b2007-07-19 01:46:57 -07002548
2549out:
Nick Piggind0217ac2007-07-19 01:47:03 -07002550 unlock_page(vmf.page);
Mark Fasheh69676142007-07-19 01:47:00 -07002551out_unlocked:
Nick Piggind00806b2007-07-19 01:46:57 -07002552 if (anon)
Nick Piggind0217ac2007-07-19 01:47:03 -07002553 page_cache_release(vmf.page);
Nick Piggind00806b2007-07-19 01:46:57 -07002554 else if (dirty_page) {
Anton Salikhmetov8f7b3d12008-01-23 02:21:18 +03002555 if (vma->vm_file)
2556 file_update_time(vma->vm_file);
2557
Peter Zijlstraa200ee12007-10-08 18:54:37 +02002558 set_page_dirty_balance(dirty_page, page_mkwrite);
Peter Zijlstrad08b3852006-09-25 23:30:57 -07002559 put_page(dirty_page);
2560 }
Nick Piggind00806b2007-07-19 01:46:57 -07002561
Nick Piggin83c54072007-07-19 01:47:05 -07002562 return ret;
Nick Piggin54cb8822007-07-19 01:46:59 -07002563}
Nick Piggind00806b2007-07-19 01:46:57 -07002564
Nick Piggin54cb8822007-07-19 01:46:59 -07002565static int do_linear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
2566 unsigned long address, pte_t *page_table, pmd_t *pmd,
2567 int write_access, pte_t orig_pte)
2568{
2569 pgoff_t pgoff = (((address & PAGE_MASK)
Dean Nelson0da7e012007-10-16 01:24:45 -07002570 - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
Nick Piggin54cb8822007-07-19 01:46:59 -07002571 unsigned int flags = (write_access ? FAULT_FLAG_WRITE : 0);
2572
Hugh Dickins16abfa02007-10-04 16:56:06 +01002573 pte_unmap(page_table);
2574 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Nick Piggin54cb8822007-07-19 01:46:59 -07002575}
2576
Jes Sorensenf4b81802006-09-27 01:50:10 -07002577/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002578 * Fault of a previously existing named mapping. Repopulate the pte
2579 * from the encoded file_pte if possible. This enables swappable
2580 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002581 *
2582 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2583 * but allow concurrent faults), and pte mapped but not yet locked.
2584 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002585 */
Nick Piggind0217ac2007-07-19 01:47:03 -07002586static int do_nonlinear_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Hugh Dickins65500d22005-10-29 18:15:59 -07002587 unsigned long address, pte_t *page_table, pmd_t *pmd,
2588 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002589{
Nick Piggind0217ac2007-07-19 01:47:03 -07002590 unsigned int flags = FAULT_FLAG_NONLINEAR |
2591 (write_access ? FAULT_FLAG_WRITE : 0);
Hugh Dickins65500d22005-10-29 18:15:59 -07002592 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002593
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002594 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Nick Piggin83c54072007-07-19 01:47:05 -07002595 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002596
Nick Piggind0217ac2007-07-19 01:47:03 -07002597 if (unlikely(!(vma->vm_flags & VM_NONLINEAR) ||
2598 !(vma->vm_flags & VM_CAN_NONLINEAR))) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002599 /*
2600 * Page table corrupted: show pte and kill process.
2601 */
Nick Pigginb5810032005-10-29 18:16:12 -07002602 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002603 return VM_FAULT_OOM;
2604 }
Hugh Dickins65500d22005-10-29 18:15:59 -07002605
2606 pgoff = pte_to_pgoff(orig_pte);
Hugh Dickins16abfa02007-10-04 16:56:06 +01002607 return __do_fault(mm, vma, address, pmd, pgoff, flags, orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002608}
2609
2610/*
2611 * These routines also need to handle stuff like marking pages dirty
2612 * and/or accessed for architectures that don't do it in hardware (most
2613 * RISC architectures). The early dirtying is also good on the i386.
2614 *
2615 * There is also a hook called "update_mmu_cache()" that architectures
2616 * with external mmu caches can use to update those (ie the Sparc or
2617 * PowerPC hashed page tables that act as extended TLBs).
2618 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002619 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2620 * but allow concurrent faults), and pte mapped but not yet locked.
2621 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002622 */
2623static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002624 struct vm_area_struct *vma, unsigned long address,
2625 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002626{
2627 pte_t entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002628 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002629
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07002630 entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002631 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002632 if (pte_none(entry)) {
Jes Sorensenf4b81802006-09-27 01:50:10 -07002633 if (vma->vm_ops) {
Nick Piggin3c18ddd2008-04-28 02:12:10 -07002634 if (likely(vma->vm_ops->fault))
Nick Piggin54cb8822007-07-19 01:46:59 -07002635 return do_linear_fault(mm, vma, address,
2636 pte, pmd, write_access, entry);
Jes Sorensenf4b81802006-09-27 01:50:10 -07002637 }
2638 return do_anonymous_page(mm, vma, address,
2639 pte, pmd, write_access);
Hugh Dickins65500d22005-10-29 18:15:59 -07002640 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002641 if (pte_file(entry))
Nick Piggind0217ac2007-07-19 01:47:03 -07002642 return do_nonlinear_fault(mm, vma, address,
Hugh Dickins65500d22005-10-29 18:15:59 -07002643 pte, pmd, write_access, entry);
2644 return do_swap_page(mm, vma, address,
2645 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002646 }
2647
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002648 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002649 spin_lock(ptl);
2650 if (unlikely(!pte_same(*pte, entry)))
2651 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002652 if (write_access) {
2653 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002654 return do_wp_page(mm, vma, address,
2655 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002656 entry = pte_mkdirty(entry);
2657 }
2658 entry = pte_mkyoung(entry);
Benjamin Herrenschmidt8dab5242007-06-16 10:16:12 -07002659 if (ptep_set_access_flags(vma, address, pte, entry, write_access)) {
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002660 update_mmu_cache(vma, address, entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002661 } else {
2662 /*
2663 * This is needed only for protection faults but the arch code
2664 * is not yet telling us if this is a protection fault or not.
2665 * This still avoids useless tlb flushes for .text page faults
2666 * with threads.
2667 */
2668 if (write_access)
2669 flush_tlb_page(vma, address);
2670 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002671unlock:
2672 pte_unmap_unlock(pte, ptl);
Nick Piggin83c54072007-07-19 01:47:05 -07002673 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002674}
2675
2676/*
2677 * By the time we get here, we already hold the mm semaphore
2678 */
Nick Piggin83c54072007-07-19 01:47:05 -07002679int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680 unsigned long address, int write_access)
2681{
2682 pgd_t *pgd;
2683 pud_t *pud;
2684 pmd_t *pmd;
2685 pte_t *pte;
2686
2687 __set_current_state(TASK_RUNNING);
2688
Christoph Lameterf8891e52006-06-30 01:55:45 -07002689 count_vm_event(PGFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002690
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002691 if (unlikely(is_vm_hugetlb_page(vma)))
2692 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002693
Linus Torvalds1da177e2005-04-16 15:20:36 -07002694 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002695 pud = pud_alloc(mm, pgd, address);
2696 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002697 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002698 pmd = pmd_alloc(mm, pud, address);
2699 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002700 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002701 pte = pte_alloc_map(mm, pmd, address);
2702 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002703 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002704
Hugh Dickinsc74df322005-10-29 18:16:23 -07002705 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002706}
2707
2708#ifndef __PAGETABLE_PUD_FOLDED
2709/*
2710 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002711 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002712 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002713int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002714{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002715 pud_t *new = pud_alloc_one(mm, address);
2716 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002717 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002718
Nick Piggin362a61a2008-05-14 06:37:36 +02002719 smp_wmb(); /* See comment in __pte_alloc */
2720
Hugh Dickins872fec12005-10-29 18:16:21 -07002721 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002722 if (pgd_present(*pgd)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08002723 pud_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002724 else
2725 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002726 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002727 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002728}
2729#endif /* __PAGETABLE_PUD_FOLDED */
2730
2731#ifndef __PAGETABLE_PMD_FOLDED
2732/*
2733 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002734 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002735 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002736int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002737{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002738 pmd_t *new = pmd_alloc_one(mm, address);
2739 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002740 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002741
Nick Piggin362a61a2008-05-14 06:37:36 +02002742 smp_wmb(); /* See comment in __pte_alloc */
2743
Hugh Dickins872fec12005-10-29 18:16:21 -07002744 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002745#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002746 if (pud_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08002747 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002748 else
2749 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002750#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002751 if (pgd_present(*pud)) /* Another has populated it */
Benjamin Herrenschmidt5e541972008-02-04 22:29:14 -08002752 pmd_free(mm, new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002753 else
2754 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002755#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002756 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002757 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002758}
2759#endif /* __PAGETABLE_PMD_FOLDED */
2760
2761int make_pages_present(unsigned long addr, unsigned long end)
2762{
2763 int ret, len, write;
2764 struct vm_area_struct * vma;
2765
2766 vma = find_vma(current->mm, addr);
2767 if (!vma)
KOSAKI Motohiroa4770972008-08-04 13:41:14 -07002768 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002769 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02002770 BUG_ON(addr >= end);
2771 BUG_ON(end > vma->vm_end);
Rolf Eike Beer68e116a2007-07-15 23:38:03 -07002772 len = DIV_ROUND_UP(end, PAGE_SIZE) - addr/PAGE_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002773 ret = get_user_pages(current, current->mm, addr,
2774 len, write, 0, NULL, NULL);
KOSAKI Motohiroa4770972008-08-04 13:41:14 -07002775 if (ret < 0) {
2776 /*
2777 SUS require strange return value to mlock
2778 - invalid addr generate to ENOMEM.
2779 - out of memory should generate EAGAIN.
2780 */
2781 if (ret == -EFAULT)
2782 ret = -ENOMEM;
2783 else if (ret == -ENOMEM)
2784 ret = -EAGAIN;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002785 return ret;
KOSAKI Motohiroa4770972008-08-04 13:41:14 -07002786 }
2787 return ret == len ? 0 : -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002788}
2789
Linus Torvalds1da177e2005-04-16 15:20:36 -07002790#if !defined(__HAVE_ARCH_GATE_AREA)
2791
2792#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002793static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002794
2795static int __init gate_vma_init(void)
2796{
2797 gate_vma.vm_mm = NULL;
2798 gate_vma.vm_start = FIXADDR_USER_START;
2799 gate_vma.vm_end = FIXADDR_USER_END;
Roland McGrathb6558c42007-01-26 00:56:47 -08002800 gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
2801 gate_vma.vm_page_prot = __P101;
Roland McGrathf47aef52007-01-26 00:56:49 -08002802 /*
2803 * Make sure the vDSO gets into every core dump.
2804 * Dumping its contents makes post-mortem fully interpretable later
2805 * without matching up the same kernel and hardware config to see
2806 * what PC values meant.
2807 */
2808 gate_vma.vm_flags |= VM_ALWAYSDUMP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002809 return 0;
2810}
2811__initcall(gate_vma_init);
2812#endif
2813
2814struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2815{
2816#ifdef AT_SYSINFO_EHDR
2817 return &gate_vma;
2818#else
2819 return NULL;
2820#endif
2821}
2822
2823int in_gate_area_no_task(unsigned long addr)
2824{
2825#ifdef AT_SYSINFO_EHDR
2826 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2827 return 1;
2828#endif
2829 return 0;
2830}
2831
2832#endif /* __HAVE_ARCH_GATE_AREA */
David Howells0ec76a12006-09-27 01:50:15 -07002833
Rik van Riel28b2ee22008-07-23 21:27:05 -07002834#ifdef CONFIG_HAVE_IOREMAP_PROT
2835static resource_size_t follow_phys(struct vm_area_struct *vma,
2836 unsigned long address, unsigned int flags,
2837 unsigned long *prot)
2838{
2839 pgd_t *pgd;
2840 pud_t *pud;
2841 pmd_t *pmd;
2842 pte_t *ptep, pte;
2843 spinlock_t *ptl;
2844 resource_size_t phys_addr = 0;
2845 struct mm_struct *mm = vma->vm_mm;
2846
2847 VM_BUG_ON(!(vma->vm_flags & (VM_IO | VM_PFNMAP)));
2848
2849 pgd = pgd_offset(mm, address);
2850 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
2851 goto no_page_table;
2852
2853 pud = pud_offset(pgd, address);
2854 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
2855 goto no_page_table;
2856
2857 pmd = pmd_offset(pud, address);
2858 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
2859 goto no_page_table;
2860
2861 /* We cannot handle huge page PFN maps. Luckily they don't exist. */
2862 if (pmd_huge(*pmd))
2863 goto no_page_table;
2864
2865 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
2866 if (!ptep)
2867 goto out;
2868
2869 pte = *ptep;
2870 if (!pte_present(pte))
2871 goto unlock;
2872 if ((flags & FOLL_WRITE) && !pte_write(pte))
2873 goto unlock;
2874 phys_addr = pte_pfn(pte);
2875 phys_addr <<= PAGE_SHIFT; /* Shift here to avoid overflow on PAE */
2876
2877 *prot = pgprot_val(pte_pgprot(pte));
2878
2879unlock:
2880 pte_unmap_unlock(ptep, ptl);
2881out:
2882 return phys_addr;
2883no_page_table:
2884 return 0;
2885}
2886
2887int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
2888 void *buf, int len, int write)
2889{
2890 resource_size_t phys_addr;
2891 unsigned long prot = 0;
2892 void *maddr;
2893 int offset = addr & (PAGE_SIZE-1);
2894
2895 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
2896 return -EINVAL;
2897
2898 phys_addr = follow_phys(vma, addr, write, &prot);
2899
2900 if (!phys_addr)
2901 return -EINVAL;
2902
2903 maddr = ioremap_prot(phys_addr, PAGE_SIZE, prot);
2904 if (write)
2905 memcpy_toio(maddr + offset, buf, len);
2906 else
2907 memcpy_fromio(buf, maddr + offset, len);
2908 iounmap(maddr);
2909
2910 return len;
2911}
2912#endif
2913
David Howells0ec76a12006-09-27 01:50:15 -07002914/*
2915 * Access another process' address space.
2916 * Source/target buffer must be kernel space,
2917 * Do not walk the page table directly, use get_user_pages
2918 */
2919int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
2920{
2921 struct mm_struct *mm;
2922 struct vm_area_struct *vma;
David Howells0ec76a12006-09-27 01:50:15 -07002923 void *old_buf = buf;
2924
2925 mm = get_task_mm(tsk);
2926 if (!mm)
2927 return 0;
2928
2929 down_read(&mm->mmap_sem);
Simon Arlott183ff222007-10-20 01:27:18 +02002930 /* ignore errors, just check how much was successfully transferred */
David Howells0ec76a12006-09-27 01:50:15 -07002931 while (len) {
2932 int bytes, ret, offset;
2933 void *maddr;
Rik van Riel28b2ee22008-07-23 21:27:05 -07002934 struct page *page = NULL;
David Howells0ec76a12006-09-27 01:50:15 -07002935
2936 ret = get_user_pages(tsk, mm, addr, 1,
2937 write, 1, &page, &vma);
Rik van Riel28b2ee22008-07-23 21:27:05 -07002938 if (ret <= 0) {
2939 /*
2940 * Check if this is a VM_IO | VM_PFNMAP VMA, which
2941 * we can access using slightly different code.
2942 */
2943#ifdef CONFIG_HAVE_IOREMAP_PROT
2944 vma = find_vma(mm, addr);
2945 if (!vma)
2946 break;
2947 if (vma->vm_ops && vma->vm_ops->access)
2948 ret = vma->vm_ops->access(vma, addr, buf,
2949 len, write);
2950 if (ret <= 0)
2951#endif
2952 break;
2953 bytes = ret;
David Howells0ec76a12006-09-27 01:50:15 -07002954 } else {
Rik van Riel28b2ee22008-07-23 21:27:05 -07002955 bytes = len;
2956 offset = addr & (PAGE_SIZE-1);
2957 if (bytes > PAGE_SIZE-offset)
2958 bytes = PAGE_SIZE-offset;
2959
2960 maddr = kmap(page);
2961 if (write) {
2962 copy_to_user_page(vma, page, addr,
2963 maddr + offset, buf, bytes);
2964 set_page_dirty_lock(page);
2965 } else {
2966 copy_from_user_page(vma, page, addr,
2967 buf, maddr + offset, bytes);
2968 }
2969 kunmap(page);
2970 page_cache_release(page);
David Howells0ec76a12006-09-27 01:50:15 -07002971 }
David Howells0ec76a12006-09-27 01:50:15 -07002972 len -= bytes;
2973 buf += bytes;
2974 addr += bytes;
2975 }
2976 up_read(&mm->mmap_sem);
2977 mmput(mm);
2978
2979 return buf - old_buf;
2980}
Andi Kleen03252912008-01-30 13:33:18 +01002981
2982/*
2983 * Print the name of a VMA.
2984 */
2985void print_vma_addr(char *prefix, unsigned long ip)
2986{
2987 struct mm_struct *mm = current->mm;
2988 struct vm_area_struct *vma;
2989
Ingo Molnare8bff742008-02-13 20:21:06 +01002990 /*
2991 * Do not print if we are in atomic
2992 * contexts (in exception stacks, etc.):
2993 */
2994 if (preempt_count())
2995 return;
2996
Andi Kleen03252912008-01-30 13:33:18 +01002997 down_read(&mm->mmap_sem);
2998 vma = find_vma(mm, ip);
2999 if (vma && vma->vm_file) {
3000 struct file *f = vma->vm_file;
3001 char *buf = (char *)__get_free_page(GFP_KERNEL);
3002 if (buf) {
3003 char *p, *s;
3004
Jan Blunckcf28b482008-02-14 19:38:44 -08003005 p = d_path(&f->f_path, buf, PAGE_SIZE);
Andi Kleen03252912008-01-30 13:33:18 +01003006 if (IS_ERR(p))
3007 p = "?";
3008 s = strrchr(p, '/');
3009 if (s)
3010 p = s+1;
3011 printk("%s%s[%lx+%lx]", prefix, p,
3012 vma->vm_start,
3013 vma->vm_end - vma->vm_start);
3014 free_page((unsigned long)buf);
3015 }
3016 }
3017 up_read(&current->mm->mmap_sem);
3018}