blob: 109e9866237ec7992daa1e7c441e07dbfe976151 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/mm/memory.c
3 *
4 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
5 */
6
7/*
8 * demand-loading started 01.12.91 - seems it is high on the list of
9 * things wanted, and it should be easy to implement. - Linus
10 */
11
12/*
13 * Ok, demand-loading was easy, shared pages a little bit tricker. Shared
14 * pages started 02.12.91, seems to work. - Linus.
15 *
16 * Tested sharing by executing about 30 /bin/sh: under the old kernel it
17 * would have taken more than the 6M I have free, but it worked well as
18 * far as I could see.
19 *
20 * Also corrected some "invalidate()"s - I wasn't doing enough of them.
21 */
22
23/*
24 * Real VM (paging to/from disk) started 18.12.91. Much more work and
25 * thought has to go into this. Oh, well..
26 * 19.12.91 - works, somewhat. Sometimes I get faults, don't know why.
27 * Found it. Everything seems to work now.
28 * 20.12.91 - Ok, making the swap-device changeable like the root.
29 */
30
31/*
32 * 05.04.94 - Multi-page memory management added for v1.1.
33 * Idea by Alex Bligh (alex@cconcepts.co.uk)
34 *
35 * 16.07.99 - Support of BIGMEM added by Gerhard Wichert, Siemens AG
36 * (Gerhard.Wichert@pdb.siemens.de)
37 *
38 * Aug/Sep 2004 Changed to four level page tables (Andi Kleen)
39 */
40
41#include <linux/kernel_stat.h>
42#include <linux/mm.h>
43#include <linux/hugetlb.h>
44#include <linux/mman.h>
45#include <linux/swap.h>
46#include <linux/highmem.h>
47#include <linux/pagemap.h>
48#include <linux/rmap.h>
49#include <linux/module.h>
Shailabh Nagar0ff92242006-07-14 00:24:37 -070050#include <linux/delayacct.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051#include <linux/init.h>
52
53#include <asm/pgalloc.h>
54#include <asm/uaccess.h>
55#include <asm/tlb.h>
56#include <asm/tlbflush.h>
57#include <asm/pgtable.h>
58
59#include <linux/swapops.h>
60#include <linux/elf.h>
61
Andy Whitcroftd41dee32005-06-23 00:07:54 -070062#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070063/* use the per-pgdat data instead for discontigmem - mbligh */
64unsigned long max_mapnr;
65struct page *mem_map;
66
67EXPORT_SYMBOL(max_mapnr);
68EXPORT_SYMBOL(mem_map);
69#endif
70
71unsigned long num_physpages;
72/*
73 * A number of key systems in x86 including ioremap() rely on the assumption
74 * that high_memory defines the upper bound on direct map memory, then end
75 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
76 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
77 * and ZONE_HIGHMEM.
78 */
79void * high_memory;
80unsigned long vmalloc_earlyreserve;
81
82EXPORT_SYMBOL(num_physpages);
83EXPORT_SYMBOL(high_memory);
84EXPORT_SYMBOL(vmalloc_earlyreserve);
85
Andi Kleena62eaf12006-02-16 23:41:58 +010086int randomize_va_space __read_mostly = 1;
87
88static int __init disable_randmaps(char *s)
89{
90 randomize_va_space = 0;
OGAWA Hirofumi9b410462006-03-31 02:30:33 -080091 return 1;
Andi Kleena62eaf12006-02-16 23:41:58 +010092}
93__setup("norandmaps", disable_randmaps);
94
95
Linus Torvalds1da177e2005-04-16 15:20:36 -070096/*
97 * If a p?d_bad entry is found while walking page tables, report
98 * the error, before resetting entry to p?d_none. Usually (but
99 * very seldom) called out from the p?d_none_or_clear_bad macros.
100 */
101
102void pgd_clear_bad(pgd_t *pgd)
103{
104 pgd_ERROR(*pgd);
105 pgd_clear(pgd);
106}
107
108void pud_clear_bad(pud_t *pud)
109{
110 pud_ERROR(*pud);
111 pud_clear(pud);
112}
113
114void pmd_clear_bad(pmd_t *pmd)
115{
116 pmd_ERROR(*pmd);
117 pmd_clear(pmd);
118}
119
120/*
121 * Note: this doesn't free the actual pages themselves. That
122 * has been handled earlier when unmapping all the memory regions.
123 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700124static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125{
Hugh Dickinse0da3822005-04-19 13:29:15 -0700126 struct page *page = pmd_page(*pmd);
127 pmd_clear(pmd);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700128 pte_lock_deinit(page);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700129 pte_free_tlb(tlb, page);
Christoph Lameterdf849a12006-06-30 01:55:38 -0700130 dec_zone_page_state(page, NR_PAGETABLE);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700131 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132}
133
Hugh Dickinse0da3822005-04-19 13:29:15 -0700134static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
135 unsigned long addr, unsigned long end,
136 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137{
138 pmd_t *pmd;
139 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700140 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141
Hugh Dickinse0da3822005-04-19 13:29:15 -0700142 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144 do {
145 next = pmd_addr_end(addr, end);
146 if (pmd_none_or_clear_bad(pmd))
147 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700148 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 } while (pmd++, addr = next, addr != end);
150
Hugh Dickinse0da3822005-04-19 13:29:15 -0700151 start &= PUD_MASK;
152 if (start < floor)
153 return;
154 if (ceiling) {
155 ceiling &= PUD_MASK;
156 if (!ceiling)
157 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700159 if (end - 1 > ceiling - 1)
160 return;
161
162 pmd = pmd_offset(pud, start);
163 pud_clear(pud);
164 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165}
166
Hugh Dickinse0da3822005-04-19 13:29:15 -0700167static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
168 unsigned long addr, unsigned long end,
169 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700170{
171 pud_t *pud;
172 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700173 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174
Hugh Dickinse0da3822005-04-19 13:29:15 -0700175 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700176 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177 do {
178 next = pud_addr_end(addr, end);
179 if (pud_none_or_clear_bad(pud))
180 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700181 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 } while (pud++, addr = next, addr != end);
183
Hugh Dickinse0da3822005-04-19 13:29:15 -0700184 start &= PGDIR_MASK;
185 if (start < floor)
186 return;
187 if (ceiling) {
188 ceiling &= PGDIR_MASK;
189 if (!ceiling)
190 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700192 if (end - 1 > ceiling - 1)
193 return;
194
195 pud = pud_offset(pgd, start);
196 pgd_clear(pgd);
197 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198}
199
200/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700201 * This function frees user-level page tables of a process.
202 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203 * Must be called with pagetable lock held.
204 */
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700205void free_pgd_range(struct mmu_gather **tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700206 unsigned long addr, unsigned long end,
207 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208{
209 pgd_t *pgd;
210 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700211 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700212
Hugh Dickinse0da3822005-04-19 13:29:15 -0700213 /*
214 * The next few lines have given us lots of grief...
215 *
216 * Why are we testing PMD* at this top level? Because often
217 * there will be no work to do at all, and we'd prefer not to
218 * go all the way down to the bottom just to discover that.
219 *
220 * Why all these "- 1"s? Because 0 represents both the bottom
221 * of the address space and the top of it (using -1 for the
222 * top wouldn't help much: the masks would do the wrong thing).
223 * The rule is that addr 0 and floor 0 refer to the bottom of
224 * the address space, but end 0 and ceiling 0 refer to the top
225 * Comparisons need to use "end - 1" and "ceiling - 1" (though
226 * that end 0 case should be mythical).
227 *
228 * Wherever addr is brought up or ceiling brought down, we must
229 * be careful to reject "the opposite 0" before it confuses the
230 * subsequent tests. But what about where end is brought down
231 * by PMD_SIZE below? no, end can't go down to 0 there.
232 *
233 * Whereas we round start (addr) and ceiling down, by different
234 * masks at different levels, in order to test whether a table
235 * now has no other vmas using it, so can be freed, we don't
236 * bother to round floor or end up - the tests don't need that.
237 */
238
239 addr &= PMD_MASK;
240 if (addr < floor) {
241 addr += PMD_SIZE;
242 if (!addr)
243 return;
244 }
245 if (ceiling) {
246 ceiling &= PMD_MASK;
247 if (!ceiling)
248 return;
249 }
250 if (end - 1 > ceiling - 1)
251 end -= PMD_SIZE;
252 if (addr > end - 1)
253 return;
254
255 start = addr;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700256 pgd = pgd_offset((*tlb)->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 do {
258 next = pgd_addr_end(addr, end);
259 if (pgd_none_or_clear_bad(pgd))
260 continue;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700261 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700263
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700264 if (!(*tlb)->fullmm)
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700265 flush_tlb_pgtables((*tlb)->mm, start, end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700266}
267
268void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700269 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700270{
271 while (vma) {
272 struct vm_area_struct *next = vma->vm_next;
273 unsigned long addr = vma->vm_start;
274
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700275 /*
276 * Hide vma from rmap and vmtruncate before freeing pgtables
277 */
278 anon_vma_unlink(vma);
279 unlink_file_vma(vma);
280
David Gibson9da61ae2006-03-22 00:08:57 -0800281 if (is_vm_hugetlb_page(vma)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700282 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700283 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700284 } else {
285 /*
286 * Optimization: gather nearby vmas into one call down
287 */
288 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
David Gibson48669202006-03-22 00:08:58 -0800289 && !is_vm_hugetlb_page(next)) {
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700290 vma = next;
291 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700292 anon_vma_unlink(vma);
293 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700294 }
295 free_pgd_range(tlb, addr, vma->vm_end,
296 floor, next? next->vm_start: ceiling);
297 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700298 vma = next;
299 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300}
301
Hugh Dickins1bb36302005-10-29 18:16:22 -0700302int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
Hugh Dickinsc74df322005-10-29 18:16:23 -0700304 struct page *new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700305 if (!new)
306 return -ENOMEM;
307
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700308 pte_lock_init(new);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700309 spin_lock(&mm->page_table_lock);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700310 if (pmd_present(*pmd)) { /* Another has populated it */
311 pte_lock_deinit(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700312 pte_free(new);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700313 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314 mm->nr_ptes++;
Christoph Lameterdf849a12006-06-30 01:55:38 -0700315 inc_zone_page_state(new, NR_PAGETABLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 pmd_populate(mm, pmd, new);
317 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700318 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700319 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320}
321
Hugh Dickins1bb36302005-10-29 18:16:22 -0700322int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700324 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
325 if (!new)
326 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327
Hugh Dickins1bb36302005-10-29 18:16:22 -0700328 spin_lock(&init_mm.page_table_lock);
329 if (pmd_present(*pmd)) /* Another has populated it */
330 pte_free_kernel(new);
331 else
332 pmd_populate_kernel(&init_mm, pmd, new);
333 spin_unlock(&init_mm.page_table_lock);
334 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335}
336
Hugh Dickinsae859762005-10-29 18:16:05 -0700337static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
338{
339 if (file_rss)
340 add_mm_counter(mm, file_rss, file_rss);
341 if (anon_rss)
342 add_mm_counter(mm, anon_rss, anon_rss);
343}
344
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800346 * This function is called to print an error when a bad pte
347 * is found. For example, we might have a PFN-mapped pte in
348 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700349 *
350 * The calling function must still handle the error.
351 */
352void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
353{
354 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
355 "vm_flags = %lx, vaddr = %lx\n",
356 (long long)pte_val(pte),
357 (vma->vm_mm == current->mm ? current->comm : "???"),
358 vma->vm_flags, vaddr);
359 dump_stack();
360}
361
Linus Torvalds67121172005-12-11 20:38:17 -0800362static inline int is_cow_mapping(unsigned int flags)
363{
364 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
365}
366
Nick Pigginb5810032005-10-29 18:16:12 -0700367/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800368 * This function gets the "struct page" associated with a pte.
369 *
370 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
371 * will have each page table entry just pointing to a raw page frame
372 * number, and as far as the VM layer is concerned, those do not have
373 * pages associated with them - even if the PFN might point to memory
374 * that otherwise is perfectly fine and has a "struct page".
375 *
376 * The way we recognize those mappings is through the rules set up
377 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
378 * and the vm_pgoff will point to the first PFN mapped: thus every
379 * page that is a raw mapping will always honor the rule
380 *
381 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
382 *
383 * and if that isn't true, the page has been COW'ed (in which case it
384 * _does_ have a "struct page" associated with it even if it is in a
385 * VM_PFNMAP range).
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800386 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800387struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800388{
Linus Torvalds6aab3412005-11-28 14:34:23 -0800389 unsigned long pfn = pte_pfn(pte);
390
Nick Pigginb7ab7952006-03-22 00:08:42 -0800391 if (unlikely(vma->vm_flags & VM_PFNMAP)) {
Linus Torvalds6aab3412005-11-28 14:34:23 -0800392 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
393 if (pfn == vma->vm_pgoff + off)
394 return NULL;
Linus Torvalds67121172005-12-11 20:38:17 -0800395 if (!is_cow_mapping(vma->vm_flags))
Linus Torvaldsfb155c12005-12-11 19:46:02 -0800396 return NULL;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800397 }
398
Nick Piggin315ab192006-03-25 16:20:22 +0100399 /*
400 * Add some anal sanity checks for now. Eventually,
401 * we should just do "return pfn_to_page(pfn)", but
402 * in the meantime we check that we get a valid pfn,
403 * and that the resulting page looks ok.
404 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800405 if (unlikely(!pfn_valid(pfn))) {
406 print_bad_pte(vma, pte, addr);
407 return NULL;
408 }
409
410 /*
411 * NOTE! We still have PageReserved() pages in the page
412 * tables.
413 *
414 * The PAGE_ZERO() pages and various VDSO mappings can
415 * cause them to exist.
416 */
417 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800418}
419
420/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700421 * copy one vm_area from one task to the other. Assumes the page tables
422 * already present in the new task to be cleared in the whole range
423 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 */
425
Hugh Dickins8c103762005-10-29 18:16:13 -0700426static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700428 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700429 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430{
Nick Pigginb5810032005-10-29 18:16:12 -0700431 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 pte_t pte = *src_pte;
433 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434
435 /* pte contains position in swap or file, so copy. */
436 if (unlikely(!pte_present(pte))) {
437 if (!pte_file(pte)) {
Christoph Lameter06972122006-06-23 02:03:35 -0700438 swp_entry_t entry = pte_to_swp_entry(pte);
439
440 swap_duplicate(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 /* make sure dst_mm is on swapoff's mmlist. */
442 if (unlikely(list_empty(&dst_mm->mmlist))) {
443 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700444 if (list_empty(&dst_mm->mmlist))
445 list_add(&dst_mm->mmlist,
446 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 spin_unlock(&mmlist_lock);
448 }
Christoph Lameter06972122006-06-23 02:03:35 -0700449 if (is_write_migration_entry(entry) &&
450 is_cow_mapping(vm_flags)) {
451 /*
452 * COW mappings require pages in both parent
453 * and child to be set to read.
454 */
455 make_migration_entry_read(&entry);
456 pte = swp_entry_to_pte(entry);
457 set_pte_at(src_mm, addr, src_pte, pte);
458 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700460 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 }
462
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 /*
464 * If it's a COW mapping, write protect it both
465 * in the parent and the child
466 */
Linus Torvalds67121172005-12-11 20:38:17 -0800467 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 ptep_set_wrprotect(src_mm, addr, src_pte);
469 pte = *src_pte;
470 }
471
472 /*
473 * If it's a shared mapping, mark it clean in
474 * the child
475 */
476 if (vm_flags & VM_SHARED)
477 pte = pte_mkclean(pte);
478 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800479
480 page = vm_normal_page(vma, addr, pte);
481 if (page) {
482 get_page(page);
483 page_dup_rmap(page);
484 rss[!!PageAnon(page)]++;
485 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700486
487out_set_pte:
488 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489}
490
491static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
492 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
493 unsigned long addr, unsigned long end)
494{
495 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700496 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700497 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700498 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499
500again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700501 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700502 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 if (!dst_pte)
504 return -ENOMEM;
505 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700506 src_ptl = pte_lockptr(src_mm, src_pmd);
Ingo Molnarf20dc5f2006-07-03 00:25:08 -0700507 spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 do {
510 /*
511 * We are holding two locks at this point - either of them
512 * could generate latencies in another task on another CPU.
513 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700514 if (progress >= 32) {
515 progress = 0;
516 if (need_resched() ||
Hugh Dickinsc74df322005-10-29 18:16:23 -0700517 need_lockbreak(src_ptl) ||
518 need_lockbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700519 break;
520 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700521 if (pte_none(*src_pte)) {
522 progress++;
523 continue;
524 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700525 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 progress += 8;
527 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528
Hugh Dickinsc74df322005-10-29 18:16:23 -0700529 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700531 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700532 pte_unmap_unlock(dst_pte - 1, dst_ptl);
533 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 if (addr != end)
535 goto again;
536 return 0;
537}
538
539static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
540 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
541 unsigned long addr, unsigned long end)
542{
543 pmd_t *src_pmd, *dst_pmd;
544 unsigned long next;
545
546 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
547 if (!dst_pmd)
548 return -ENOMEM;
549 src_pmd = pmd_offset(src_pud, addr);
550 do {
551 next = pmd_addr_end(addr, end);
552 if (pmd_none_or_clear_bad(src_pmd))
553 continue;
554 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
555 vma, addr, next))
556 return -ENOMEM;
557 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
558 return 0;
559}
560
561static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
562 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
563 unsigned long addr, unsigned long end)
564{
565 pud_t *src_pud, *dst_pud;
566 unsigned long next;
567
568 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
569 if (!dst_pud)
570 return -ENOMEM;
571 src_pud = pud_offset(src_pgd, addr);
572 do {
573 next = pud_addr_end(addr, end);
574 if (pud_none_or_clear_bad(src_pud))
575 continue;
576 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
577 vma, addr, next))
578 return -ENOMEM;
579 } while (dst_pud++, src_pud++, addr = next, addr != end);
580 return 0;
581}
582
583int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
584 struct vm_area_struct *vma)
585{
586 pgd_t *src_pgd, *dst_pgd;
587 unsigned long next;
588 unsigned long addr = vma->vm_start;
589 unsigned long end = vma->vm_end;
590
Nick Piggind9928952005-08-28 16:49:11 +1000591 /*
592 * Don't copy ptes where a page fault will fill them correctly.
593 * Fork becomes much lighter when there are big shared or private
594 * readonly mappings. The tradeoff is that copy_page_range is more
595 * efficient than faulting.
596 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800597 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000598 if (!vma->anon_vma)
599 return 0;
600 }
601
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602 if (is_vm_hugetlb_page(vma))
603 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
604
605 dst_pgd = pgd_offset(dst_mm, addr);
606 src_pgd = pgd_offset(src_mm, addr);
607 do {
608 next = pgd_addr_end(addr, end);
609 if (pgd_none_or_clear_bad(src_pgd))
610 continue;
611 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
612 vma, addr, next))
613 return -ENOMEM;
614 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
615 return 0;
616}
617
Robin Holt51c6f662005-11-13 16:06:42 -0800618static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700619 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800621 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622{
Nick Pigginb5810032005-10-29 18:16:12 -0700623 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700625 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700626 int file_rss = 0;
627 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628
Hugh Dickins508034a2005-10-29 18:16:30 -0700629 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 do {
631 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800632 if (pte_none(ptent)) {
633 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800635 }
Hugh Dickins6f5e6b92006-03-16 23:04:09 -0800636
637 (*zap_work) -= PAGE_SIZE;
638
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800640 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800641
Linus Torvalds6aab3412005-11-28 14:34:23 -0800642 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 if (unlikely(details) && page) {
644 /*
645 * unmap_shared_mapping_pages() wants to
646 * invalidate cache without truncating:
647 * unmap shared but keep private pages.
648 */
649 if (details->check_mapping &&
650 details->check_mapping != page->mapping)
651 continue;
652 /*
653 * Each page->index must be checked when
654 * invalidating or truncating nonlinear.
655 */
656 if (details->nonlinear_vma &&
657 (page->index < details->first_index ||
658 page->index > details->last_index))
659 continue;
660 }
Nick Pigginb5810032005-10-29 18:16:12 -0700661 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700662 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 tlb_remove_tlb_entry(tlb, pte, addr);
664 if (unlikely(!page))
665 continue;
666 if (unlikely(details) && details->nonlinear_vma
667 && linear_page_index(details->nonlinear_vma,
668 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700669 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700672 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700673 else {
674 if (pte_dirty(ptent))
675 set_page_dirty(page);
676 if (pte_young(ptent))
677 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700678 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700679 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680 page_remove_rmap(page);
681 tlb_remove_page(tlb, page);
682 continue;
683 }
684 /*
685 * If details->check_mapping, we leave swap entries;
686 * if details->nonlinear_vma, we leave file entries.
687 */
688 if (unlikely(details))
689 continue;
690 if (!pte_file(ptent))
691 free_swap_and_cache(pte_to_swp_entry(ptent));
Nick Pigginb5810032005-10-29 18:16:12 -0700692 pte_clear_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800693 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700694
Hugh Dickins86d912f2005-10-29 18:16:14 -0700695 add_mm_rss(mm, file_rss, anon_rss);
Hugh Dickins508034a2005-10-29 18:16:30 -0700696 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800697
698 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699}
700
Robin Holt51c6f662005-11-13 16:06:42 -0800701static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700702 struct vm_area_struct *vma, pud_t *pud,
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{
706 pmd_t *pmd;
707 unsigned long next;
708
709 pmd = pmd_offset(pud, addr);
710 do {
711 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800712 if (pmd_none_or_clear_bad(pmd)) {
713 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800715 }
716 next = zap_pte_range(tlb, vma, pmd, addr, next,
717 zap_work, details);
718 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
719
720 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700721}
722
Robin Holt51c6f662005-11-13 16:06:42 -0800723static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700724 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800726 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
728 pud_t *pud;
729 unsigned long next;
730
731 pud = pud_offset(pgd, addr);
732 do {
733 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800734 if (pud_none_or_clear_bad(pud)) {
735 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700736 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800737 }
738 next = zap_pmd_range(tlb, vma, pud, addr, next,
739 zap_work, details);
740 } while (pud++, addr = next, (addr != end && *zap_work > 0));
741
742 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743}
744
Robin Holt51c6f662005-11-13 16:06:42 -0800745static unsigned long unmap_page_range(struct mmu_gather *tlb,
746 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800748 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749{
750 pgd_t *pgd;
751 unsigned long next;
752
753 if (details && !details->check_mapping && !details->nonlinear_vma)
754 details = NULL;
755
756 BUG_ON(addr >= end);
757 tlb_start_vma(tlb, vma);
758 pgd = pgd_offset(vma->vm_mm, addr);
759 do {
760 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800761 if (pgd_none_or_clear_bad(pgd)) {
762 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800764 }
765 next = zap_pud_range(tlb, vma, pgd, addr, next,
766 zap_work, details);
767 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800769
770 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771}
772
773#ifdef CONFIG_PREEMPT
774# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
775#else
776/* No preempt: go for improved straight-line efficiency */
777# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
778#endif
779
780/**
781 * unmap_vmas - unmap a range of memory covered by a list of vma's
782 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 * @vma: the starting vma
784 * @start_addr: virtual address at which to start unmapping
785 * @end_addr: virtual address at which to end unmapping
786 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
787 * @details: details of nonlinear truncation or shared cache invalidation
788 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700789 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700790 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700791 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700792 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700793 * We aim to not hold locks for too long (for scheduling latency reasons).
794 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 * return the ending mmu_gather to the caller.
796 *
797 * Only addresses between `start' and `end' will be unmapped.
798 *
799 * The VMA list must be sorted in ascending virtual address order.
800 *
801 * unmap_vmas() assumes that the caller will flush the whole unmapped address
802 * range after unmap_vmas() returns. So the only responsibility here is to
803 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
804 * drops the lock and schedules.
805 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700806unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700807 struct vm_area_struct *vma, unsigned long start_addr,
808 unsigned long end_addr, unsigned long *nr_accounted,
809 struct zap_details *details)
810{
Robin Holt51c6f662005-11-13 16:06:42 -0800811 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700812 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
813 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700814 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700815 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700816 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817
818 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819 unsigned long end;
820
821 start = max(vma->vm_start, start_addr);
822 if (start >= vma->vm_end)
823 continue;
824 end = min(vma->vm_end, end_addr);
825 if (end <= vma->vm_start)
826 continue;
827
828 if (vma->vm_flags & VM_ACCOUNT)
829 *nr_accounted += (end - start) >> PAGE_SHIFT;
830
Linus Torvalds1da177e2005-04-16 15:20:36 -0700831 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 if (!tlb_start_valid) {
833 tlb_start = start;
834 tlb_start_valid = 1;
835 }
836
Robin Holt51c6f662005-11-13 16:06:42 -0800837 if (unlikely(is_vm_hugetlb_page(vma))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 unmap_hugepage_range(vma, start, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800839 zap_work -= (end - start) /
840 (HPAGE_SIZE / PAGE_SIZE);
841 start = end;
842 } else
843 start = unmap_page_range(*tlbp, vma,
844 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700845
Robin Holt51c6f662005-11-13 16:06:42 -0800846 if (zap_work > 0) {
847 BUG_ON(start != end);
848 break;
849 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850
851 tlb_finish_mmu(*tlbp, tlb_start, start);
852
853 if (need_resched() ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
855 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700856 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700857 goto out;
858 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 }
861
Hugh Dickins508034a2005-10-29 18:16:30 -0700862 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800864 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 }
866 }
867out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700868 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700869}
870
871/**
872 * zap_page_range - remove user pages in a given range
873 * @vma: vm_area_struct holding the applicable pages
874 * @address: starting address of pages to zap
875 * @size: number of bytes to zap
876 * @details: details of nonlinear truncation or shared cache invalidation
877 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700878unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879 unsigned long size, struct zap_details *details)
880{
881 struct mm_struct *mm = vma->vm_mm;
882 struct mmu_gather *tlb;
883 unsigned long end = address + size;
884 unsigned long nr_accounted = 0;
885
Linus Torvalds1da177e2005-04-16 15:20:36 -0700886 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700888 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700889 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
890 if (tlb)
891 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700892 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893}
894
895/*
896 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700897 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800898struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700899 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700900{
901 pgd_t *pgd;
902 pud_t *pud;
903 pmd_t *pmd;
904 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700905 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800907 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700908
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700909 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
910 if (!IS_ERR(page)) {
911 BUG_ON(flags & FOLL_GET);
912 goto out;
913 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700915 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700916 pgd = pgd_offset(mm, address);
917 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700918 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700919
920 pud = pud_offset(pgd, address);
921 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700922 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923
924 pmd = pmd_offset(pud, address);
925 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700926 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700927
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700928 if (pmd_huge(*pmd)) {
929 BUG_ON(flags & FOLL_GET);
930 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
931 goto out;
932 }
933
934 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 if (!ptep)
936 goto out;
937
938 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700939 if (!pte_present(pte))
940 goto unlock;
941 if ((flags & FOLL_WRITE) && !pte_write(pte))
942 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800943 page = vm_normal_page(vma, address, pte);
944 if (unlikely(!page))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700945 goto unlock;
946
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700947 if (flags & FOLL_GET)
948 get_page(page);
949 if (flags & FOLL_TOUCH) {
950 if ((flags & FOLL_WRITE) &&
951 !pte_dirty(pte) && !PageDirty(page))
952 set_page_dirty(page);
953 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700955unlock:
956 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700957out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700958 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700960no_page_table:
961 /*
962 * When core dumping an enormous anonymous area that nobody
963 * has touched so far, we don't want to allocate page tables.
964 */
965 if (flags & FOLL_ANON) {
966 page = ZERO_PAGE(address);
967 if (flags & FOLL_GET)
968 get_page(page);
969 BUG_ON(flags & FOLL_WRITE);
970 }
971 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700972}
973
Linus Torvalds1da177e2005-04-16 15:20:36 -0700974int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
975 unsigned long start, int len, int write, int force,
976 struct page **pages, struct vm_area_struct **vmas)
977{
978 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700979 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700980
981 /*
982 * Require read or write permissions.
983 * If 'force' is set, we only require the "MAY" flags.
984 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700985 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
986 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987 i = 0;
988
989 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700990 struct vm_area_struct *vma;
991 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992
993 vma = find_extend_vma(mm, start);
994 if (!vma && in_gate_area(tsk, start)) {
995 unsigned long pg = start & PAGE_MASK;
996 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
997 pgd_t *pgd;
998 pud_t *pud;
999 pmd_t *pmd;
1000 pte_t *pte;
1001 if (write) /* user gate pages are read-only */
1002 return i ? : -EFAULT;
1003 if (pg > TASK_SIZE)
1004 pgd = pgd_offset_k(pg);
1005 else
1006 pgd = pgd_offset_gate(mm, pg);
1007 BUG_ON(pgd_none(*pgd));
1008 pud = pud_offset(pgd, pg);
1009 BUG_ON(pud_none(*pud));
1010 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001011 if (pmd_none(*pmd))
1012 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001013 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -07001014 if (pte_none(*pte)) {
1015 pte_unmap(pte);
1016 return i ? : -EFAULT;
1017 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +11001019 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001020 pages[i] = page;
1021 if (page)
1022 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001023 }
1024 pte_unmap(pte);
1025 if (vmas)
1026 vmas[i] = gate_vma;
1027 i++;
1028 start += PAGE_SIZE;
1029 len--;
1030 continue;
1031 }
1032
Linus Torvalds1ff80382005-12-12 16:24:33 -08001033 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001034 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001035 return i ? : -EFAULT;
1036
1037 if (is_vm_hugetlb_page(vma)) {
1038 i = follow_hugetlb_page(mm, vma, pages, vmas,
1039 &start, &len, i);
1040 continue;
1041 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001042
1043 foll_flags = FOLL_TOUCH;
1044 if (pages)
1045 foll_flags |= FOLL_GET;
1046 if (!write && !(vma->vm_flags & VM_LOCKED) &&
1047 (!vma->vm_ops || !vma->vm_ops->nopage))
1048 foll_flags |= FOLL_ANON;
1049
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001051 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001052
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001053 if (write)
1054 foll_flags |= FOLL_WRITE;
1055
1056 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001057 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001058 int ret;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001059 ret = __handle_mm_fault(mm, vma, start,
1060 foll_flags & FOLL_WRITE);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001061 /*
1062 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1063 * broken COW when necessary, even if maybe_mkwrite
1064 * decided not to set pte_write. We can thus safely do
1065 * subsequent page lookups as if they were reads.
1066 */
1067 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001068 foll_flags &= ~FOLL_WRITE;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001069
1070 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071 case VM_FAULT_MINOR:
1072 tsk->min_flt++;
1073 break;
1074 case VM_FAULT_MAJOR:
1075 tsk->maj_flt++;
1076 break;
1077 case VM_FAULT_SIGBUS:
1078 return i ? i : -EFAULT;
1079 case VM_FAULT_OOM:
1080 return i ? i : -ENOMEM;
1081 default:
1082 BUG();
1083 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084 }
1085 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001086 pages[i] = page;
James Bottomley03beb072006-03-26 01:36:57 -08001087
1088 flush_anon_page(page, start);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001089 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001090 }
1091 if (vmas)
1092 vmas[i] = vma;
1093 i++;
1094 start += PAGE_SIZE;
1095 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001096 } while (len && start < vma->vm_end);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001097 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 return i;
1099}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001100EXPORT_SYMBOL(get_user_pages);
1101
1102static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1103 unsigned long addr, unsigned long end, pgprot_t prot)
1104{
1105 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001106 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001107
Hugh Dickinsc74df322005-10-29 18:16:23 -07001108 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001109 if (!pte)
1110 return -ENOMEM;
1111 do {
Nick Pigginb5810032005-10-29 18:16:12 -07001112 struct page *page = ZERO_PAGE(addr);
1113 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1114 page_cache_get(page);
1115 page_add_file_rmap(page);
1116 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001117 BUG_ON(!pte_none(*pte));
1118 set_pte_at(mm, addr, pte, zero_pte);
1119 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001120 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001121 return 0;
1122}
1123
1124static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1125 unsigned long addr, unsigned long end, pgprot_t prot)
1126{
1127 pmd_t *pmd;
1128 unsigned long next;
1129
1130 pmd = pmd_alloc(mm, pud, addr);
1131 if (!pmd)
1132 return -ENOMEM;
1133 do {
1134 next = pmd_addr_end(addr, end);
1135 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1136 return -ENOMEM;
1137 } while (pmd++, addr = next, addr != end);
1138 return 0;
1139}
1140
1141static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1142 unsigned long addr, unsigned long end, pgprot_t prot)
1143{
1144 pud_t *pud;
1145 unsigned long next;
1146
1147 pud = pud_alloc(mm, pgd, addr);
1148 if (!pud)
1149 return -ENOMEM;
1150 do {
1151 next = pud_addr_end(addr, end);
1152 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1153 return -ENOMEM;
1154 } while (pud++, addr = next, addr != end);
1155 return 0;
1156}
1157
1158int zeromap_page_range(struct vm_area_struct *vma,
1159 unsigned long addr, unsigned long size, pgprot_t prot)
1160{
1161 pgd_t *pgd;
1162 unsigned long next;
1163 unsigned long end = addr + size;
1164 struct mm_struct *mm = vma->vm_mm;
1165 int err;
1166
1167 BUG_ON(addr >= end);
1168 pgd = pgd_offset(mm, addr);
1169 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001170 do {
1171 next = pgd_addr_end(addr, end);
1172 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1173 if (err)
1174 break;
1175 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176 return err;
1177}
1178
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001179pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001180{
1181 pgd_t * pgd = pgd_offset(mm, addr);
1182 pud_t * pud = pud_alloc(mm, pgd, addr);
1183 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001184 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001185 if (pmd)
1186 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1187 }
1188 return NULL;
1189}
1190
Linus Torvalds1da177e2005-04-16 15:20:36 -07001191/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001192 * This is the old fallback for page remapping.
1193 *
1194 * For historical reasons, it only allows reserved pages. Only
1195 * old drivers should use this, and they needed to mark their
1196 * pages reserved for the old functions anyway.
1197 */
1198static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
1199{
1200 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001201 pte_t *pte;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001202 spinlock_t *ptl;
1203
1204 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001205 if (PageAnon(page))
Linus Torvalds238f58d2005-11-29 13:01:56 -08001206 goto out;
1207 retval = -ENOMEM;
1208 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001209 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001210 if (!pte)
1211 goto out;
1212 retval = -EBUSY;
1213 if (!pte_none(*pte))
1214 goto out_unlock;
1215
1216 /* Ok, finally just insert the thing.. */
1217 get_page(page);
1218 inc_mm_counter(mm, file_rss);
1219 page_add_file_rmap(page);
1220 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1221
1222 retval = 0;
1223out_unlock:
1224 pte_unmap_unlock(pte, ptl);
1225out:
1226 return retval;
1227}
1228
1229/*
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001230 * This allows drivers to insert individual pages they've allocated
1231 * into a user vma.
1232 *
1233 * The page has to be a nice clean _individual_ kernel allocation.
1234 * If you allocate a compound page, you need to have marked it as
1235 * such (__GFP_COMP), or manually just split the page up yourself
Nick Piggin8dfcc9b2006-03-22 00:08:05 -08001236 * (see split_page()).
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001237 *
1238 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1239 * took an arbitrary page protection parameter. This doesn't allow
1240 * that. Your vma protection will have to be set up correctly, which
1241 * means that if you want a shared writable mapping, you'd better
1242 * ask for a shared writable mapping!
1243 *
1244 * The page does not need to be reserved.
1245 */
1246int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1247{
1248 if (addr < vma->vm_start || addr >= vma->vm_end)
1249 return -EFAULT;
1250 if (!page_count(page))
1251 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001252 vma->vm_flags |= VM_INSERTPAGE;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001253 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1254}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001255EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001256
1257/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001258 * maps a range of physical memory into the requested pages. the old
1259 * mappings are removed. any references to nonexistent pages results
1260 * in null mappings (currently treated as "copy-on-access")
1261 */
1262static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1263 unsigned long addr, unsigned long end,
1264 unsigned long pfn, pgprot_t prot)
1265{
1266 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001267 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268
Hugh Dickinsc74df322005-10-29 18:16:23 -07001269 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001270 if (!pte)
1271 return -ENOMEM;
1272 do {
1273 BUG_ON(!pte_none(*pte));
Nick Pigginb5810032005-10-29 18:16:12 -07001274 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001275 pfn++;
1276 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001277 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001278 return 0;
1279}
1280
1281static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1282 unsigned long addr, unsigned long end,
1283 unsigned long pfn, pgprot_t prot)
1284{
1285 pmd_t *pmd;
1286 unsigned long next;
1287
1288 pfn -= addr >> PAGE_SHIFT;
1289 pmd = pmd_alloc(mm, pud, addr);
1290 if (!pmd)
1291 return -ENOMEM;
1292 do {
1293 next = pmd_addr_end(addr, end);
1294 if (remap_pte_range(mm, pmd, addr, next,
1295 pfn + (addr >> PAGE_SHIFT), prot))
1296 return -ENOMEM;
1297 } while (pmd++, addr = next, addr != end);
1298 return 0;
1299}
1300
1301static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1302 unsigned long addr, unsigned long end,
1303 unsigned long pfn, pgprot_t prot)
1304{
1305 pud_t *pud;
1306 unsigned long next;
1307
1308 pfn -= addr >> PAGE_SHIFT;
1309 pud = pud_alloc(mm, pgd, addr);
1310 if (!pud)
1311 return -ENOMEM;
1312 do {
1313 next = pud_addr_end(addr, end);
1314 if (remap_pmd_range(mm, pud, addr, next,
1315 pfn + (addr >> PAGE_SHIFT), prot))
1316 return -ENOMEM;
1317 } while (pud++, addr = next, addr != end);
1318 return 0;
1319}
1320
1321/* Note: this is only safe if the mm semaphore is held when called. */
1322int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1323 unsigned long pfn, unsigned long size, pgprot_t prot)
1324{
1325 pgd_t *pgd;
1326 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001327 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001328 struct mm_struct *mm = vma->vm_mm;
1329 int err;
1330
1331 /*
1332 * Physically remapped pages are special. Tell the
1333 * rest of the world about it:
1334 * VM_IO tells people not to look at these pages
1335 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001336 * VM_RESERVED is specified all over the place, because
1337 * in 2.4 it kept swapout's vma scan off this vma; but
1338 * in 2.6 the LRU scan won't even find its pages, so this
1339 * flag means no more than count its pages in reserved_vm,
1340 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001341 * VM_PFNMAP tells the core MM that the base pages are just
1342 * raw PFN mappings, and do not have a "struct page" associated
1343 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001344 *
1345 * There's a horrible special case to handle copy-on-write
1346 * behaviour that some programs depend on. We mark the "original"
1347 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001348 */
Linus Torvalds67121172005-12-11 20:38:17 -08001349 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001350 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001351 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001352 vma->vm_pgoff = pfn;
1353 }
1354
Linus Torvalds6aab3412005-11-28 14:34:23 -08001355 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001356
1357 BUG_ON(addr >= end);
1358 pfn -= addr >> PAGE_SHIFT;
1359 pgd = pgd_offset(mm, addr);
1360 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001361 do {
1362 next = pgd_addr_end(addr, end);
1363 err = remap_pud_range(mm, pgd, addr, next,
1364 pfn + (addr >> PAGE_SHIFT), prot);
1365 if (err)
1366 break;
1367 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001368 return err;
1369}
1370EXPORT_SYMBOL(remap_pfn_range);
1371
1372/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001373 * handle_pte_fault chooses page fault handler according to an entry
1374 * which was read non-atomically. Before making any commitment, on
1375 * those architectures or configurations (e.g. i386 with PAE) which
1376 * might give a mix of unmatched parts, do_swap_page and do_file_page
1377 * must check under lock before unmapping the pte and proceeding
1378 * (but do_wp_page is only called after already making such a check;
1379 * and do_anonymous_page and do_no_page can safely check later on).
1380 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001381static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001382 pte_t *page_table, pte_t orig_pte)
1383{
1384 int same = 1;
1385#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1386 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001387 spinlock_t *ptl = pte_lockptr(mm, pmd);
1388 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001389 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001390 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001391 }
1392#endif
1393 pte_unmap(page_table);
1394 return same;
1395}
1396
1397/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001398 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1399 * servicing faults for write access. In the normal case, do always want
1400 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1401 * that do not have writing enabled, when used by access_process_vm.
1402 */
1403static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1404{
1405 if (likely(vma->vm_flags & VM_WRITE))
1406 pte = pte_mkwrite(pte);
1407 return pte;
1408}
1409
Linus Torvalds6aab3412005-11-28 14:34:23 -08001410static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
1411{
1412 /*
1413 * If the source page was a PFN mapping, we don't have
1414 * a "struct page" for it. We do a best-effort copy by
1415 * just copying from the original user address. If that
1416 * fails, we just zero-fill it. Live with it.
1417 */
1418 if (unlikely(!src)) {
1419 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2dbbc2005-11-29 14:07:55 -08001420 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1421
1422 /*
1423 * This really shouldn't fail, because the page is there
1424 * in the page tables. But it might just be unreadable,
1425 * in which case we just give up and fill the result with
1426 * zeroes.
1427 */
1428 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001429 memset(kaddr, 0, PAGE_SIZE);
1430 kunmap_atomic(kaddr, KM_USER0);
1431 return;
1432
1433 }
1434 copy_user_highpage(dst, src, va);
1435}
1436
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001438 * This routine handles present pages, when users try to write
1439 * to a shared page. It is done by copying the page to a new address
1440 * and decrementing the shared-page counter for the old page.
1441 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001442 * Note that this routine assumes that the protection checks have been
1443 * done by the caller (the low-level page fault routine in most cases).
1444 * Thus we can safely just mark it writable once we've done any necessary
1445 * COW.
1446 *
1447 * We also mark the page dirty at this point even though the page will
1448 * change only once the write actually happens. This avoids a few races,
1449 * and potentially makes it more efficient.
1450 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001451 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1452 * but allow concurrent faults), with pte both mapped and locked.
1453 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001454 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001455static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1456 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001457 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001459 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460 pte_t entry;
David Howells9637a5e2006-06-23 02:03:43 -07001461 int reuse, ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001462
Linus Torvalds6aab3412005-11-28 14:34:23 -08001463 old_page = vm_normal_page(vma, address, orig_pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001464 if (!old_page)
1465 goto gotten;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466
David Howells9637a5e2006-06-23 02:03:43 -07001467 if (unlikely((vma->vm_flags & (VM_SHARED|VM_WRITE)) ==
1468 (VM_SHARED|VM_WRITE))) {
1469 if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
1470 /*
1471 * Notify the address space that the page is about to
1472 * become writable so that it can prohibit this or wait
1473 * for the page to get into an appropriate state.
1474 *
1475 * We do this without the lock held, so that it can
1476 * sleep if it needs to.
1477 */
1478 page_cache_get(old_page);
1479 pte_unmap_unlock(page_table, ptl);
1480
1481 if (vma->vm_ops->page_mkwrite(vma, old_page) < 0)
1482 goto unwritable_page;
1483
1484 page_cache_release(old_page);
1485
1486 /*
1487 * Since we dropped the lock we need to revalidate
1488 * the PTE as someone else may have changed it. If
1489 * they did, we just return, as we can count on the
1490 * MMU to tell us if they didn't also make it writable.
1491 */
1492 page_table = pte_offset_map_lock(mm, pmd, address,
1493 &ptl);
1494 if (!pte_same(*page_table, orig_pte))
1495 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001496 }
David Howells9637a5e2006-06-23 02:03:43 -07001497
1498 reuse = 1;
1499 } else if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
1500 reuse = can_share_swap_page(old_page);
1501 unlock_page(old_page);
1502 } else {
1503 reuse = 0;
1504 }
1505
1506 if (reuse) {
1507 flush_cache_page(vma, address, pte_pfn(orig_pte));
1508 entry = pte_mkyoung(orig_pte);
1509 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1510 ptep_set_access_flags(vma, address, page_table, entry, 1);
1511 update_mmu_cache(vma, address, entry);
1512 lazy_mmu_prot_update(entry);
1513 ret |= VM_FAULT_WRITE;
1514 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001515 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516
1517 /*
1518 * Ok, we need to copy. Oh, well..
1519 */
Nick Pigginb5810032005-10-29 18:16:12 -07001520 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001521gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001522 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001523
1524 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001525 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001526 if (old_page == ZERO_PAGE(address)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001527 new_page = alloc_zeroed_user_highpage(vma, address);
1528 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001529 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001530 } else {
1531 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1532 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001533 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001534 cow_user_page(new_page, old_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001535 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001536
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537 /*
1538 * Re-check the pte - we dropped the lock
1539 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001540 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001541 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001542 if (old_page) {
1543 page_remove_rmap(old_page);
1544 if (!PageAnon(old_page)) {
1545 dec_mm_counter(mm, file_rss);
1546 inc_mm_counter(mm, anon_rss);
1547 }
1548 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001549 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001550 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001551 entry = mk_pte(new_page, vma->vm_page_prot);
1552 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Anil Keshavamurthyc38c8db2006-07-14 00:23:57 -07001553 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001554 ptep_establish(vma, address, page_table, entry);
1555 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001556 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08001557 page_add_new_anon_rmap(new_page, vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001558
1559 /* Free the old page.. */
1560 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001561 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001562 }
Hugh Dickins920fc352005-11-21 21:32:17 -08001563 if (new_page)
1564 page_cache_release(new_page);
1565 if (old_page)
1566 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001567unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001568 pte_unmap_unlock(page_table, ptl);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001569 return ret;
Hugh Dickins65500d22005-10-29 18:15:59 -07001570oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001571 if (old_page)
1572 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001573 return VM_FAULT_OOM;
David Howells9637a5e2006-06-23 02:03:43 -07001574
1575unwritable_page:
1576 page_cache_release(old_page);
1577 return VM_FAULT_SIGBUS;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001578}
1579
1580/*
1581 * Helper functions for unmap_mapping_range().
1582 *
1583 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1584 *
1585 * We have to restart searching the prio_tree whenever we drop the lock,
1586 * since the iterator is only valid while the lock is held, and anyway
1587 * a later vma might be split and reinserted earlier while lock dropped.
1588 *
1589 * The list of nonlinear vmas could be handled more efficiently, using
1590 * a placeholder, but handle it in the same way until a need is shown.
1591 * It is important to search the prio_tree before nonlinear list: a vma
1592 * may become nonlinear and be shifted from prio_tree to nonlinear list
1593 * while the lock is dropped; but never shifted from list to prio_tree.
1594 *
1595 * In order to make forward progress despite restarting the search,
1596 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1597 * quickly skip it next time around. Since the prio_tree search only
1598 * shows us those vmas affected by unmapping the range in question, we
1599 * can't efficiently keep all vmas in step with mapping->truncate_count:
1600 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1601 * mapping->truncate_count and vma->vm_truncate_count are protected by
1602 * i_mmap_lock.
1603 *
1604 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001605 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001606 * and restart from that address when we reach that vma again. It might
1607 * have been split or merged, shrunk or extended, but never shifted: so
1608 * restart_addr remains valid so long as it remains in the vma's range.
1609 * unmap_mapping_range forces truncate_count to leap over page-aligned
1610 * values so we can save vma's restart_addr in its truncate_count field.
1611 */
1612#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1613
1614static void reset_vma_truncate_counts(struct address_space *mapping)
1615{
1616 struct vm_area_struct *vma;
1617 struct prio_tree_iter iter;
1618
1619 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1620 vma->vm_truncate_count = 0;
1621 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1622 vma->vm_truncate_count = 0;
1623}
1624
1625static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1626 unsigned long start_addr, unsigned long end_addr,
1627 struct zap_details *details)
1628{
1629 unsigned long restart_addr;
1630 int need_break;
1631
1632again:
1633 restart_addr = vma->vm_truncate_count;
1634 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1635 start_addr = restart_addr;
1636 if (start_addr >= end_addr) {
1637 /* Top of vma has been split off since last time */
1638 vma->vm_truncate_count = details->truncate_count;
1639 return 0;
1640 }
1641 }
1642
Hugh Dickinsee39b372005-04-19 13:29:15 -07001643 restart_addr = zap_page_range(vma, start_addr,
1644 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001645 need_break = need_resched() ||
1646 need_lockbreak(details->i_mmap_lock);
1647
Hugh Dickinsee39b372005-04-19 13:29:15 -07001648 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001649 /* We have now completed this vma: mark it so */
1650 vma->vm_truncate_count = details->truncate_count;
1651 if (!need_break)
1652 return 0;
1653 } else {
1654 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001655 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001656 if (!need_break)
1657 goto again;
1658 }
1659
1660 spin_unlock(details->i_mmap_lock);
1661 cond_resched();
1662 spin_lock(details->i_mmap_lock);
1663 return -EINTR;
1664}
1665
1666static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1667 struct zap_details *details)
1668{
1669 struct vm_area_struct *vma;
1670 struct prio_tree_iter iter;
1671 pgoff_t vba, vea, zba, zea;
1672
1673restart:
1674 vma_prio_tree_foreach(vma, &iter, root,
1675 details->first_index, details->last_index) {
1676 /* Skip quickly over those we have already dealt with */
1677 if (vma->vm_truncate_count == details->truncate_count)
1678 continue;
1679
1680 vba = vma->vm_pgoff;
1681 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1682 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1683 zba = details->first_index;
1684 if (zba < vba)
1685 zba = vba;
1686 zea = details->last_index;
1687 if (zea > vea)
1688 zea = vea;
1689
1690 if (unmap_mapping_range_vma(vma,
1691 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1692 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1693 details) < 0)
1694 goto restart;
1695 }
1696}
1697
1698static inline void unmap_mapping_range_list(struct list_head *head,
1699 struct zap_details *details)
1700{
1701 struct vm_area_struct *vma;
1702
1703 /*
1704 * In nonlinear VMAs there is no correspondence between virtual address
1705 * offset and file offset. So we must perform an exhaustive search
1706 * across *all* the pages in each nonlinear VMA, not just the pages
1707 * whose virtual address lies outside the file truncation point.
1708 */
1709restart:
1710 list_for_each_entry(vma, head, shared.vm_set.list) {
1711 /* Skip quickly over those we have already dealt with */
1712 if (vma->vm_truncate_count == details->truncate_count)
1713 continue;
1714 details->nonlinear_vma = vma;
1715 if (unmap_mapping_range_vma(vma, vma->vm_start,
1716 vma->vm_end, details) < 0)
1717 goto restart;
1718 }
1719}
1720
1721/**
1722 * unmap_mapping_range - unmap the portion of all mmaps
1723 * in the specified address_space corresponding to the specified
1724 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001725 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001726 * @holebegin: byte in first page to unmap, relative to the start of
1727 * the underlying file. This will be rounded down to a PAGE_SIZE
1728 * boundary. Note that this is different from vmtruncate(), which
1729 * must keep the partial page. In contrast, we must get rid of
1730 * partial pages.
1731 * @holelen: size of prospective hole in bytes. This will be rounded
1732 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1733 * end of the file.
1734 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1735 * but 0 when invalidating pagecache, don't throw away private data.
1736 */
1737void unmap_mapping_range(struct address_space *mapping,
1738 loff_t const holebegin, loff_t const holelen, int even_cows)
1739{
1740 struct zap_details details;
1741 pgoff_t hba = holebegin >> PAGE_SHIFT;
1742 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1743
1744 /* Check for overflow. */
1745 if (sizeof(holelen) > sizeof(hlen)) {
1746 long long holeend =
1747 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1748 if (holeend & ~(long long)ULONG_MAX)
1749 hlen = ULONG_MAX - hba + 1;
1750 }
1751
1752 details.check_mapping = even_cows? NULL: mapping;
1753 details.nonlinear_vma = NULL;
1754 details.first_index = hba;
1755 details.last_index = hba + hlen - 1;
1756 if (details.last_index < details.first_index)
1757 details.last_index = ULONG_MAX;
1758 details.i_mmap_lock = &mapping->i_mmap_lock;
1759
1760 spin_lock(&mapping->i_mmap_lock);
1761
1762 /* serialize i_size write against truncate_count write */
1763 smp_wmb();
1764 /* Protect against page faults, and endless unmapping loops */
1765 mapping->truncate_count++;
1766 /*
1767 * For archs where spin_lock has inclusive semantics like ia64
1768 * this smp_mb() will prevent to read pagetable contents
1769 * before the truncate_count increment is visible to
1770 * other cpus.
1771 */
1772 smp_mb();
1773 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1774 if (mapping->truncate_count == 0)
1775 reset_vma_truncate_counts(mapping);
1776 mapping->truncate_count++;
1777 }
1778 details.truncate_count = mapping->truncate_count;
1779
1780 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1781 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1782 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1783 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1784 spin_unlock(&mapping->i_mmap_lock);
1785}
1786EXPORT_SYMBOL(unmap_mapping_range);
1787
1788/*
1789 * Handle all mappings that got truncated by a "truncate()"
1790 * system call.
1791 *
1792 * NOTE! We have to be ready to update the memory sharing
1793 * between the file and the memory map for a potential last
1794 * incomplete page. Ugly, but necessary.
1795 */
1796int vmtruncate(struct inode * inode, loff_t offset)
1797{
1798 struct address_space *mapping = inode->i_mapping;
1799 unsigned long limit;
1800
1801 if (inode->i_size < offset)
1802 goto do_expand;
1803 /*
1804 * truncation of in-use swapfiles is disallowed - it would cause
1805 * subsequent swapout to scribble on the now-freed blocks.
1806 */
1807 if (IS_SWAPFILE(inode))
1808 goto out_busy;
1809 i_size_write(inode, offset);
1810 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1811 truncate_inode_pages(mapping, offset);
1812 goto out_truncate;
1813
1814do_expand:
1815 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1816 if (limit != RLIM_INFINITY && offset > limit)
1817 goto out_sig;
1818 if (offset > inode->i_sb->s_maxbytes)
1819 goto out_big;
1820 i_size_write(inode, offset);
1821
1822out_truncate:
1823 if (inode->i_op && inode->i_op->truncate)
1824 inode->i_op->truncate(inode);
1825 return 0;
1826out_sig:
1827 send_sig(SIGXFSZ, current, 0);
1828out_big:
1829 return -EFBIG;
1830out_busy:
1831 return -ETXTBSY;
1832}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833EXPORT_SYMBOL(vmtruncate);
1834
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001835int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
1836{
1837 struct address_space *mapping = inode->i_mapping;
1838
1839 /*
1840 * If the underlying filesystem is not going to provide
1841 * a way to truncate a range of blocks (punch a hole) -
1842 * we should return failure right now.
1843 */
1844 if (!inode->i_op || !inode->i_op->truncate_range)
1845 return -ENOSYS;
1846
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001847 mutex_lock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001848 down_write(&inode->i_alloc_sem);
1849 unmap_mapping_range(mapping, offset, (end - offset), 1);
1850 truncate_inode_pages_range(mapping, offset, end);
1851 inode->i_op->truncate_range(inode, offset, end);
1852 up_write(&inode->i_alloc_sem);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -08001853 mutex_unlock(&inode->i_mutex);
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001854
1855 return 0;
1856}
Adrian Bunk26fc5232006-07-10 04:44:22 -07001857EXPORT_UNUSED_SYMBOL(vmtruncate_range); /* June 2006 */
Badari Pulavartyf6b3ec22006-01-06 00:10:38 -08001858
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859/*
1860 * Primitive swap readahead code. We simply read an aligned block of
1861 * (1 << page_cluster) entries in the swap area. This method is chosen
1862 * because it doesn't cost us any seek time. We also make sure to queue
1863 * the 'original' request together with the readahead ones...
1864 *
1865 * This has been extended to use the NUMA policies from the mm triggering
1866 * the readahead.
1867 *
1868 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1869 */
1870void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1871{
1872#ifdef CONFIG_NUMA
1873 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1874#endif
1875 int i, num;
1876 struct page *new_page;
1877 unsigned long offset;
1878
1879 /*
1880 * Get the number of handles we should do readahead io to.
1881 */
1882 num = valid_swaphandles(entry, &offset);
1883 for (i = 0; i < num; offset++, i++) {
1884 /* Ok, do the async read-ahead now */
1885 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1886 offset), vma, addr);
1887 if (!new_page)
1888 break;
1889 page_cache_release(new_page);
1890#ifdef CONFIG_NUMA
1891 /*
1892 * Find the next applicable VMA for the NUMA policy.
1893 */
1894 addr += PAGE_SIZE;
1895 if (addr == 0)
1896 vma = NULL;
1897 if (vma) {
1898 if (addr >= vma->vm_end) {
1899 vma = next_vma;
1900 next_vma = vma ? vma->vm_next : NULL;
1901 }
1902 if (vma && addr < vma->vm_start)
1903 vma = NULL;
1904 } else {
1905 if (next_vma && addr >= next_vma->vm_start) {
1906 vma = next_vma;
1907 next_vma = vma->vm_next;
1908 }
1909 }
1910#endif
1911 }
1912 lru_add_drain(); /* Push any new pages onto the LRU now */
1913}
1914
1915/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001916 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1917 * but allow concurrent faults), and pte mapped but not yet locked.
1918 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001919 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001920static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1921 unsigned long address, pte_t *page_table, pmd_t *pmd,
1922 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001923{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001924 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001925 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001926 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001927 pte_t pte;
1928 int ret = VM_FAULT_MINOR;
1929
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001930 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001931 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07001932
1933 entry = pte_to_swp_entry(orig_pte);
Christoph Lameter06972122006-06-23 02:03:35 -07001934 if (is_migration_entry(entry)) {
1935 migration_entry_wait(mm, pmd, address);
1936 goto out;
1937 }
Shailabh Nagar0ff92242006-07-14 00:24:37 -07001938 delayacct_set_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001939 page = lookup_swap_cache(entry);
1940 if (!page) {
1941 swapin_readahead(entry, address, vma);
1942 page = read_swap_cache_async(entry, vma, address);
1943 if (!page) {
1944 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001945 * Back out if somebody else faulted in this pte
1946 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001947 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001948 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001949 if (likely(pte_same(*page_table, orig_pte)))
1950 ret = VM_FAULT_OOM;
Shailabh Nagar0ff92242006-07-14 00:24:37 -07001951 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Hugh Dickins65500d22005-10-29 18:15:59 -07001952 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001953 }
1954
1955 /* Had to read the page from swap area: Major fault */
1956 ret = VM_FAULT_MAJOR;
Christoph Lameterf8891e52006-06-30 01:55:45 -07001957 count_vm_event(PGMAJFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001958 grab_swap_token();
1959 }
1960
Shailabh Nagar0ff92242006-07-14 00:24:37 -07001961 delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001962 mark_page_accessed(page);
1963 lock_page(page);
1964
1965 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001966 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001967 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001968 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07001969 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07001970 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001971
1972 if (unlikely(!PageUptodate(page))) {
1973 ret = VM_FAULT_SIGBUS;
1974 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001975 }
1976
1977 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978
Hugh Dickins42946212005-10-29 18:16:05 -07001979 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 pte = mk_pte(page, vma->vm_page_prot);
1981 if (write_access && can_share_swap_page(page)) {
1982 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1983 write_access = 0;
1984 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985
1986 flush_icache_page(vma, page);
1987 set_pte_at(mm, address, page_table, pte);
1988 page_add_anon_rmap(page, vma, address);
1989
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001990 swap_free(entry);
1991 if (vm_swap_full())
1992 remove_exclusive_swap_page(page);
1993 unlock_page(page);
1994
Linus Torvalds1da177e2005-04-16 15:20:36 -07001995 if (write_access) {
1996 if (do_wp_page(mm, vma, address,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001997 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001998 ret = VM_FAULT_OOM;
1999 goto out;
2000 }
2001
2002 /* No need to invalidate - it was non-present before */
2003 update_mmu_cache(vma, address, pte);
2004 lazy_mmu_prot_update(pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07002005unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002006 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007out:
2008 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07002009out_nomap:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002010 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07002011 unlock_page(page);
2012 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002013 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002014}
2015
2016/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002017 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2018 * but allow concurrent faults), and pte mapped but not yet locked.
2019 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002020 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002021static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
2022 unsigned long address, pte_t *page_table, pmd_t *pmd,
2023 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002024{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002025 struct page *page;
2026 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002027 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002028
Linus Torvalds6aab3412005-11-28 14:34:23 -08002029 if (write_access) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002030 /* Allocate our own private page. */
2031 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002032
2033 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07002034 goto oom;
2035 page = alloc_zeroed_user_highpage(vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002036 if (!page)
Hugh Dickins65500d22005-10-29 18:15:59 -07002037 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002038
Hugh Dickins65500d22005-10-29 18:15:59 -07002039 entry = mk_pte(page, vma->vm_page_prot);
2040 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002041
2042 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
2043 if (!pte_none(*page_table))
2044 goto release;
2045 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002046 lru_cache_add_active(page);
Nick Piggin9617d952006-01-06 00:11:12 -08002047 page_add_new_anon_rmap(page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07002048 } else {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002049 /* Map the ZERO_PAGE - vm_page_prot is readonly */
2050 page = ZERO_PAGE(address);
2051 page_cache_get(page);
2052 entry = mk_pte(page, vma->vm_page_prot);
2053
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002054 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002055 spin_lock(ptl);
2056 if (!pte_none(*page_table))
2057 goto release;
Nick Pigginb5810032005-10-29 18:16:12 -07002058 inc_mm_counter(mm, file_rss);
2059 page_add_file_rmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002060 }
2061
Hugh Dickins65500d22005-10-29 18:15:59 -07002062 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002063
2064 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07002065 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002067unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002068 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002069 return VM_FAULT_MINOR;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002070release:
2071 page_cache_release(page);
2072 goto unlock;
Hugh Dickins65500d22005-10-29 18:15:59 -07002073oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002074 return VM_FAULT_OOM;
2075}
2076
2077/*
2078 * do_no_page() tries to create a new page mapping. It aggressively
2079 * tries to share with existing pages, but makes a separate copy if
2080 * the "write_access" parameter is true in order to avoid the next
2081 * page fault.
2082 *
2083 * As this is called only for pages that do not currently exist, we
2084 * do not need to flush old virtual caches or the TLB.
2085 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002086 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2087 * but allow concurrent faults), and pte mapped but not yet locked.
2088 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002089 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002090static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2091 unsigned long address, pte_t *page_table, pmd_t *pmd,
2092 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002093{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002094 spinlock_t *ptl;
Hugh Dickins65500d22005-10-29 18:15:59 -07002095 struct page *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 struct address_space *mapping = NULL;
2097 pte_t entry;
2098 unsigned int sequence = 0;
2099 int ret = VM_FAULT_MINOR;
2100 int anon = 0;
2101
Linus Torvalds1da177e2005-04-16 15:20:36 -07002102 pte_unmap(page_table);
Hugh Dickins325f04d2005-11-29 16:55:48 +00002103 BUG_ON(vma->vm_flags & VM_PFNMAP);
2104
Linus Torvalds1da177e2005-04-16 15:20:36 -07002105 if (vma->vm_file) {
2106 mapping = vma->vm_file->f_mapping;
2107 sequence = mapping->truncate_count;
2108 smp_rmb(); /* serializes i_size against truncate_count */
2109 }
2110retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002111 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2112 /*
2113 * No smp_rmb is needed here as long as there's a full
2114 * spin_lock/unlock sequence inside the ->nopage callback
2115 * (for the pagecache lookup) that acts as an implicit
2116 * smp_mb() and prevents the i_size read to happen
2117 * after the next truncate_count read.
2118 */
2119
2120 /* no page was available -- either SIGBUS or OOM */
2121 if (new_page == NOPAGE_SIGBUS)
2122 return VM_FAULT_SIGBUS;
2123 if (new_page == NOPAGE_OOM)
2124 return VM_FAULT_OOM;
2125
2126 /*
2127 * Should we do an early C-O-W break?
2128 */
David Howells9637a5e2006-06-23 02:03:43 -07002129 if (write_access) {
2130 if (!(vma->vm_flags & VM_SHARED)) {
2131 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002132
David Howells9637a5e2006-06-23 02:03:43 -07002133 if (unlikely(anon_vma_prepare(vma)))
2134 goto oom;
2135 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
2136 if (!page)
2137 goto oom;
2138 copy_user_highpage(page, new_page, address);
2139 page_cache_release(new_page);
2140 new_page = page;
2141 anon = 1;
2142
2143 } else {
2144 /* if the page will be shareable, see if the backing
2145 * address space wants to know that the page is about
2146 * to become writable */
2147 if (vma->vm_ops->page_mkwrite &&
2148 vma->vm_ops->page_mkwrite(vma, new_page) < 0
2149 ) {
2150 page_cache_release(new_page);
2151 return VM_FAULT_SIGBUS;
2152 }
2153 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002154 }
2155
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002156 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002157 /*
2158 * For a file-backed vma, someone could have truncated or otherwise
2159 * invalidated this page. If unmap_mapping_range got called,
2160 * retry getting the page.
2161 */
2162 if (mapping && unlikely(sequence != mapping->truncate_count)) {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002163 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002164 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002165 cond_resched();
2166 sequence = mapping->truncate_count;
2167 smp_rmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002168 goto retry;
2169 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002170
2171 /*
2172 * This silly early PAGE_DIRTY setting removes a race
2173 * due to the bad i386 page protection. But it's valid
2174 * for other architectures too.
2175 *
2176 * Note that if write_access is true, we either now have
2177 * an exclusive copy of the page, or this is a shared mapping,
2178 * so we can make it writable and dirty to avoid having to
2179 * handle that later.
2180 */
2181 /* Only go through if we didn't race with anybody else... */
2182 if (pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002183 flush_icache_page(vma, new_page);
2184 entry = mk_pte(new_page, vma->vm_page_prot);
2185 if (write_access)
2186 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2187 set_pte_at(mm, address, page_table, entry);
2188 if (anon) {
Hugh Dickins42946212005-10-29 18:16:05 -07002189 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 lru_cache_add_active(new_page);
Nick Piggin9617d952006-01-06 00:11:12 -08002191 page_add_new_anon_rmap(new_page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002192 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002193 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002194 page_add_file_rmap(new_page);
Hugh Dickins42946212005-10-29 18:16:05 -07002195 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002196 } else {
2197 /* One of our sibling threads was faster, back out. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002198 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002199 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002200 }
2201
2202 /* no need to invalidate: a not-present page shouldn't be cached */
2203 update_mmu_cache(vma, address, entry);
2204 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002205unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002206 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002207 return ret;
2208oom:
2209 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002210 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002211}
2212
2213/*
2214 * Fault of a previously existing named mapping. Repopulate the pte
2215 * from the encoded file_pte if possible. This enables swappable
2216 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002217 *
2218 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2219 * but allow concurrent faults), and pte mapped but not yet locked.
2220 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002221 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002222static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
2223 unsigned long address, pte_t *page_table, pmd_t *pmd,
2224 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002225{
Hugh Dickins65500d22005-10-29 18:15:59 -07002226 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002227 int err;
2228
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002229 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002230 return VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002231
Hugh Dickins65500d22005-10-29 18:15:59 -07002232 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
2233 /*
2234 * Page table corrupted: show pte and kill process.
2235 */
Nick Pigginb5810032005-10-29 18:16:12 -07002236 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002237 return VM_FAULT_OOM;
2238 }
2239 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2240
2241 pgoff = pte_to_pgoff(orig_pte);
2242 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
2243 vma->vm_page_prot, pgoff, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244 if (err == -ENOMEM)
2245 return VM_FAULT_OOM;
2246 if (err)
2247 return VM_FAULT_SIGBUS;
2248 return VM_FAULT_MAJOR;
2249}
2250
2251/*
2252 * These routines also need to handle stuff like marking pages dirty
2253 * and/or accessed for architectures that don't do it in hardware (most
2254 * RISC architectures). The early dirtying is also good on the i386.
2255 *
2256 * There is also a hook called "update_mmu_cache()" that architectures
2257 * with external mmu caches can use to update those (ie the Sparc or
2258 * PowerPC hashed page tables that act as extended TLBs).
2259 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002260 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2261 * but allow concurrent faults), and pte mapped but not yet locked.
2262 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002263 */
2264static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002265 struct vm_area_struct *vma, unsigned long address,
2266 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002267{
2268 pte_t entry;
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002269 pte_t old_entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002270 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002271
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002272 old_entry = entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002274 if (pte_none(entry)) {
2275 if (!vma->vm_ops || !vma->vm_ops->nopage)
2276 return do_anonymous_page(mm, vma, address,
2277 pte, pmd, write_access);
2278 return do_no_page(mm, vma, address,
2279 pte, pmd, write_access);
2280 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281 if (pte_file(entry))
Hugh Dickins65500d22005-10-29 18:15:59 -07002282 return do_file_page(mm, vma, address,
2283 pte, pmd, write_access, entry);
2284 return do_swap_page(mm, vma, address,
2285 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002286 }
2287
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002288 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002289 spin_lock(ptl);
2290 if (unlikely(!pte_same(*pte, entry)))
2291 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002292 if (write_access) {
2293 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002294 return do_wp_page(mm, vma, address,
2295 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002296 entry = pte_mkdirty(entry);
2297 }
2298 entry = pte_mkyoung(entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002299 if (!pte_same(old_entry, entry)) {
2300 ptep_set_access_flags(vma, address, pte, entry, write_access);
2301 update_mmu_cache(vma, address, entry);
2302 lazy_mmu_prot_update(entry);
2303 } else {
2304 /*
2305 * This is needed only for protection faults but the arch code
2306 * is not yet telling us if this is a protection fault or not.
2307 * This still avoids useless tlb flushes for .text page faults
2308 * with threads.
2309 */
2310 if (write_access)
2311 flush_tlb_page(vma, address);
2312 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002313unlock:
2314 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002315 return VM_FAULT_MINOR;
2316}
2317
2318/*
2319 * By the time we get here, we already hold the mm semaphore
2320 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002321int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002322 unsigned long address, int write_access)
2323{
2324 pgd_t *pgd;
2325 pud_t *pud;
2326 pmd_t *pmd;
2327 pte_t *pte;
2328
2329 __set_current_state(TASK_RUNNING);
2330
Christoph Lameterf8891e52006-06-30 01:55:45 -07002331 count_vm_event(PGFAULT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002332
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002333 if (unlikely(is_vm_hugetlb_page(vma)))
2334 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002335
Linus Torvalds1da177e2005-04-16 15:20:36 -07002336 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002337 pud = pud_alloc(mm, pgd, address);
2338 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002339 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002340 pmd = pmd_alloc(mm, pud, address);
2341 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002342 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002343 pte = pte_alloc_map(mm, pmd, address);
2344 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002345 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002346
Hugh Dickinsc74df322005-10-29 18:16:23 -07002347 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002348}
2349
Arnd Bergmann67207b92005-11-15 15:53:48 -05002350EXPORT_SYMBOL_GPL(__handle_mm_fault);
2351
Linus Torvalds1da177e2005-04-16 15:20:36 -07002352#ifndef __PAGETABLE_PUD_FOLDED
2353/*
2354 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002355 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002356 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002357int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002358{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002359 pud_t *new = pud_alloc_one(mm, address);
2360 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002361 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002362
Hugh Dickins872fec12005-10-29 18:16:21 -07002363 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002364 if (pgd_present(*pgd)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002365 pud_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002366 else
2367 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002368 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002369 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370}
Alan Sterne0f39592005-11-28 13:43:44 -08002371#else
2372/* Workaround for gcc 2.96 */
2373int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2374{
2375 return 0;
2376}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002377#endif /* __PAGETABLE_PUD_FOLDED */
2378
2379#ifndef __PAGETABLE_PMD_FOLDED
2380/*
2381 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002382 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002384int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002385{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002386 pmd_t *new = pmd_alloc_one(mm, address);
2387 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002388 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002389
Hugh Dickins872fec12005-10-29 18:16:21 -07002390 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002391#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002392 if (pud_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002393 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002394 else
2395 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002396#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002397 if (pgd_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002398 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002399 else
2400 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002401#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002402 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002403 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002404}
Alan Sterne0f39592005-11-28 13:43:44 -08002405#else
2406/* Workaround for gcc 2.96 */
2407int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2408{
2409 return 0;
2410}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002411#endif /* __PAGETABLE_PMD_FOLDED */
2412
2413int make_pages_present(unsigned long addr, unsigned long end)
2414{
2415 int ret, len, write;
2416 struct vm_area_struct * vma;
2417
2418 vma = find_vma(current->mm, addr);
2419 if (!vma)
2420 return -1;
2421 write = (vma->vm_flags & VM_WRITE) != 0;
Eric Sesterhenn5bcb28b2006-03-26 18:30:52 +02002422 BUG_ON(addr >= end);
2423 BUG_ON(end > vma->vm_end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2425 ret = get_user_pages(current, current->mm, addr,
2426 len, write, 0, NULL, NULL);
2427 if (ret < 0)
2428 return ret;
2429 return ret == len ? 0 : -1;
2430}
2431
2432/*
2433 * Map a vmalloc()-space virtual address to the physical page.
2434 */
2435struct page * vmalloc_to_page(void * vmalloc_addr)
2436{
2437 unsigned long addr = (unsigned long) vmalloc_addr;
2438 struct page *page = NULL;
2439 pgd_t *pgd = pgd_offset_k(addr);
2440 pud_t *pud;
2441 pmd_t *pmd;
2442 pte_t *ptep, pte;
2443
2444 if (!pgd_none(*pgd)) {
2445 pud = pud_offset(pgd, addr);
2446 if (!pud_none(*pud)) {
2447 pmd = pmd_offset(pud, addr);
2448 if (!pmd_none(*pmd)) {
2449 ptep = pte_offset_map(pmd, addr);
2450 pte = *ptep;
2451 if (pte_present(pte))
2452 page = pte_page(pte);
2453 pte_unmap(ptep);
2454 }
2455 }
2456 }
2457 return page;
2458}
2459
2460EXPORT_SYMBOL(vmalloc_to_page);
2461
2462/*
2463 * Map a vmalloc()-space virtual address to the physical page frame number.
2464 */
2465unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2466{
2467 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2468}
2469
2470EXPORT_SYMBOL(vmalloc_to_pfn);
2471
Linus Torvalds1da177e2005-04-16 15:20:36 -07002472#if !defined(__HAVE_ARCH_GATE_AREA)
2473
2474#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002475static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002476
2477static int __init gate_vma_init(void)
2478{
2479 gate_vma.vm_mm = NULL;
2480 gate_vma.vm_start = FIXADDR_USER_START;
2481 gate_vma.vm_end = FIXADDR_USER_END;
2482 gate_vma.vm_page_prot = PAGE_READONLY;
Hugh Dickins0b14c172005-11-21 21:32:15 -08002483 gate_vma.vm_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002484 return 0;
2485}
2486__initcall(gate_vma_init);
2487#endif
2488
2489struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2490{
2491#ifdef AT_SYSINFO_EHDR
2492 return &gate_vma;
2493#else
2494 return NULL;
2495#endif
2496}
2497
2498int in_gate_area_no_task(unsigned long addr)
2499{
2500#ifdef AT_SYSINFO_EHDR
2501 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2502 return 1;
2503#endif
2504 return 0;
2505}
2506
2507#endif /* __HAVE_ARCH_GATE_AREA */