blob: d8dde07a36566fc6463b7b9b95305d9b0505427e [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>
50#include <linux/init.h>
51
52#include <asm/pgalloc.h>
53#include <asm/uaccess.h>
54#include <asm/tlb.h>
55#include <asm/tlbflush.h>
56#include <asm/pgtable.h>
57
58#include <linux/swapops.h>
59#include <linux/elf.h>
60
Andy Whitcroftd41dee32005-06-23 00:07:54 -070061#ifndef CONFIG_NEED_MULTIPLE_NODES
Linus Torvalds1da177e2005-04-16 15:20:36 -070062/* use the per-pgdat data instead for discontigmem - mbligh */
63unsigned long max_mapnr;
64struct page *mem_map;
65
66EXPORT_SYMBOL(max_mapnr);
67EXPORT_SYMBOL(mem_map);
68#endif
69
70unsigned long num_physpages;
71/*
72 * A number of key systems in x86 including ioremap() rely on the assumption
73 * that high_memory defines the upper bound on direct map memory, then end
74 * of ZONE_NORMAL. Under CONFIG_DISCONTIG this means that max_low_pfn and
75 * highstart_pfn must be the same; there must be no gap between ZONE_NORMAL
76 * and ZONE_HIGHMEM.
77 */
78void * high_memory;
79unsigned long vmalloc_earlyreserve;
80
81EXPORT_SYMBOL(num_physpages);
82EXPORT_SYMBOL(high_memory);
83EXPORT_SYMBOL(vmalloc_earlyreserve);
84
85/*
86 * If a p?d_bad entry is found while walking page tables, report
87 * the error, before resetting entry to p?d_none. Usually (but
88 * very seldom) called out from the p?d_none_or_clear_bad macros.
89 */
90
91void pgd_clear_bad(pgd_t *pgd)
92{
93 pgd_ERROR(*pgd);
94 pgd_clear(pgd);
95}
96
97void pud_clear_bad(pud_t *pud)
98{
99 pud_ERROR(*pud);
100 pud_clear(pud);
101}
102
103void pmd_clear_bad(pmd_t *pmd)
104{
105 pmd_ERROR(*pmd);
106 pmd_clear(pmd);
107}
108
109/*
110 * Note: this doesn't free the actual pages themselves. That
111 * has been handled earlier when unmapping all the memory regions.
112 */
Hugh Dickinse0da3822005-04-19 13:29:15 -0700113static void free_pte_range(struct mmu_gather *tlb, pmd_t *pmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
Hugh Dickinse0da3822005-04-19 13:29:15 -0700115 struct page *page = pmd_page(*pmd);
116 pmd_clear(pmd);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700117 pte_lock_deinit(page);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700118 pte_free_tlb(tlb, page);
119 dec_page_state(nr_page_table_pages);
120 tlb->mm->nr_ptes--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121}
122
Hugh Dickinse0da3822005-04-19 13:29:15 -0700123static inline void free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
124 unsigned long addr, unsigned long end,
125 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700126{
127 pmd_t *pmd;
128 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700129 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130
Hugh Dickinse0da3822005-04-19 13:29:15 -0700131 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 pmd = pmd_offset(pud, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133 do {
134 next = pmd_addr_end(addr, end);
135 if (pmd_none_or_clear_bad(pmd))
136 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700137 free_pte_range(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138 } while (pmd++, addr = next, addr != end);
139
Hugh Dickinse0da3822005-04-19 13:29:15 -0700140 start &= PUD_MASK;
141 if (start < floor)
142 return;
143 if (ceiling) {
144 ceiling &= PUD_MASK;
145 if (!ceiling)
146 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700148 if (end - 1 > ceiling - 1)
149 return;
150
151 pmd = pmd_offset(pud, start);
152 pud_clear(pud);
153 pmd_free_tlb(tlb, pmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
155
Hugh Dickinse0da3822005-04-19 13:29:15 -0700156static inline void free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
157 unsigned long addr, unsigned long end,
158 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159{
160 pud_t *pud;
161 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700162 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
Hugh Dickinse0da3822005-04-19 13:29:15 -0700164 start = addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165 pud = pud_offset(pgd, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166 do {
167 next = pud_addr_end(addr, end);
168 if (pud_none_or_clear_bad(pud))
169 continue;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700170 free_pmd_range(tlb, pud, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 } while (pud++, addr = next, addr != end);
172
Hugh Dickinse0da3822005-04-19 13:29:15 -0700173 start &= PGDIR_MASK;
174 if (start < floor)
175 return;
176 if (ceiling) {
177 ceiling &= PGDIR_MASK;
178 if (!ceiling)
179 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700181 if (end - 1 > ceiling - 1)
182 return;
183
184 pud = pud_offset(pgd, start);
185 pgd_clear(pgd);
186 pud_free_tlb(tlb, pud);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187}
188
189/*
Hugh Dickinse0da3822005-04-19 13:29:15 -0700190 * This function frees user-level page tables of a process.
191 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700192 * Must be called with pagetable lock held.
193 */
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700194void free_pgd_range(struct mmu_gather **tlb,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700195 unsigned long addr, unsigned long end,
196 unsigned long floor, unsigned long ceiling)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197{
198 pgd_t *pgd;
199 unsigned long next;
Hugh Dickinse0da3822005-04-19 13:29:15 -0700200 unsigned long start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700201
Hugh Dickinse0da3822005-04-19 13:29:15 -0700202 /*
203 * The next few lines have given us lots of grief...
204 *
205 * Why are we testing PMD* at this top level? Because often
206 * there will be no work to do at all, and we'd prefer not to
207 * go all the way down to the bottom just to discover that.
208 *
209 * Why all these "- 1"s? Because 0 represents both the bottom
210 * of the address space and the top of it (using -1 for the
211 * top wouldn't help much: the masks would do the wrong thing).
212 * The rule is that addr 0 and floor 0 refer to the bottom of
213 * the address space, but end 0 and ceiling 0 refer to the top
214 * Comparisons need to use "end - 1" and "ceiling - 1" (though
215 * that end 0 case should be mythical).
216 *
217 * Wherever addr is brought up or ceiling brought down, we must
218 * be careful to reject "the opposite 0" before it confuses the
219 * subsequent tests. But what about where end is brought down
220 * by PMD_SIZE below? no, end can't go down to 0 there.
221 *
222 * Whereas we round start (addr) and ceiling down, by different
223 * masks at different levels, in order to test whether a table
224 * now has no other vmas using it, so can be freed, we don't
225 * bother to round floor or end up - the tests don't need that.
226 */
227
228 addr &= PMD_MASK;
229 if (addr < floor) {
230 addr += PMD_SIZE;
231 if (!addr)
232 return;
233 }
234 if (ceiling) {
235 ceiling &= PMD_MASK;
236 if (!ceiling)
237 return;
238 }
239 if (end - 1 > ceiling - 1)
240 end -= PMD_SIZE;
241 if (addr > end - 1)
242 return;
243
244 start = addr;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700245 pgd = pgd_offset((*tlb)->mm, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246 do {
247 next = pgd_addr_end(addr, end);
248 if (pgd_none_or_clear_bad(pgd))
249 continue;
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700250 free_pud_range(*tlb, pgd, addr, next, floor, ceiling);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700251 } while (pgd++, addr = next, addr != end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700252
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700253 if (!(*tlb)->fullmm)
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700254 flush_tlb_pgtables((*tlb)->mm, start, end);
Hugh Dickinse0da3822005-04-19 13:29:15 -0700255}
256
257void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700258 unsigned long floor, unsigned long ceiling)
Hugh Dickinse0da3822005-04-19 13:29:15 -0700259{
260 while (vma) {
261 struct vm_area_struct *next = vma->vm_next;
262 unsigned long addr = vma->vm_start;
263
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700264 /*
265 * Hide vma from rmap and vmtruncate before freeing pgtables
266 */
267 anon_vma_unlink(vma);
268 unlink_file_vma(vma);
269
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700270 if (is_hugepage_only_range(vma->vm_mm, addr, HPAGE_SIZE)) {
271 hugetlb_free_pgd_range(tlb, addr, vma->vm_end,
Hugh Dickinse0da3822005-04-19 13:29:15 -0700272 floor, next? next->vm_start: ceiling);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700273 } else {
274 /*
275 * Optimization: gather nearby vmas into one call down
276 */
277 while (next && next->vm_start <= vma->vm_end + PMD_SIZE
278 && !is_hugepage_only_range(vma->vm_mm, next->vm_start,
279 HPAGE_SIZE)) {
280 vma = next;
281 next = vma->vm_next;
Hugh Dickins8f4f8c12005-10-29 18:16:29 -0700282 anon_vma_unlink(vma);
283 unlink_file_vma(vma);
Hugh Dickins3bf5ee92005-04-19 13:29:16 -0700284 }
285 free_pgd_range(tlb, addr, vma->vm_end,
286 floor, next? next->vm_start: ceiling);
287 }
Hugh Dickinse0da3822005-04-19 13:29:15 -0700288 vma = next;
289 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290}
291
Hugh Dickins1bb36302005-10-29 18:16:22 -0700292int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293{
Hugh Dickinsc74df322005-10-29 18:16:23 -0700294 struct page *new = pte_alloc_one(mm, address);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700295 if (!new)
296 return -ENOMEM;
297
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700298 pte_lock_init(new);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700299 spin_lock(&mm->page_table_lock);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700300 if (pmd_present(*pmd)) { /* Another has populated it */
301 pte_lock_deinit(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700302 pte_free(new);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700303 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 mm->nr_ptes++;
305 inc_page_state(nr_page_table_pages);
306 pmd_populate(mm, pmd, new);
307 }
Hugh Dickinsc74df322005-10-29 18:16:23 -0700308 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -0700309 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310}
311
Hugh Dickins1bb36302005-10-29 18:16:22 -0700312int __pte_alloc_kernel(pmd_t *pmd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313{
Hugh Dickins1bb36302005-10-29 18:16:22 -0700314 pte_t *new = pte_alloc_one_kernel(&init_mm, address);
315 if (!new)
316 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700317
Hugh Dickins1bb36302005-10-29 18:16:22 -0700318 spin_lock(&init_mm.page_table_lock);
319 if (pmd_present(*pmd)) /* Another has populated it */
320 pte_free_kernel(new);
321 else
322 pmd_populate_kernel(&init_mm, pmd, new);
323 spin_unlock(&init_mm.page_table_lock);
324 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325}
326
Hugh Dickinsae859762005-10-29 18:16:05 -0700327static inline void add_mm_rss(struct mm_struct *mm, int file_rss, int anon_rss)
328{
329 if (file_rss)
330 add_mm_counter(mm, file_rss, file_rss);
331 if (anon_rss)
332 add_mm_counter(mm, anon_rss, anon_rss);
333}
334
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800336 * This function is called to print an error when a bad pte
337 * is found. For example, we might have a PFN-mapped pte in
338 * a region that doesn't allow it.
Nick Pigginb5810032005-10-29 18:16:12 -0700339 *
340 * The calling function must still handle the error.
341 */
342void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
343{
344 printk(KERN_ERR "Bad pte = %08llx, process = %s, "
345 "vm_flags = %lx, vaddr = %lx\n",
346 (long long)pte_val(pte),
347 (vma->vm_mm == current->mm ? current->comm : "???"),
348 vma->vm_flags, vaddr);
349 dump_stack();
350}
351
Linus Torvalds67121172005-12-11 20:38:17 -0800352static inline int is_cow_mapping(unsigned int flags)
353{
354 return (flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
355}
356
Nick Pigginb5810032005-10-29 18:16:12 -0700357/*
Linus Torvalds6aab3412005-11-28 14:34:23 -0800358 * This function gets the "struct page" associated with a pte.
359 *
360 * NOTE! Some mappings do not have "struct pages". A raw PFN mapping
361 * will have each page table entry just pointing to a raw page frame
362 * number, and as far as the VM layer is concerned, those do not have
363 * pages associated with them - even if the PFN might point to memory
364 * that otherwise is perfectly fine and has a "struct page".
365 *
366 * The way we recognize those mappings is through the rules set up
367 * by "remap_pfn_range()": the vma will have the VM_PFNMAP bit set,
368 * and the vm_pgoff will point to the first PFN mapped: thus every
369 * page that is a raw mapping will always honor the rule
370 *
371 * pfn_of_page == vma->vm_pgoff + ((addr - vma->vm_start) >> PAGE_SHIFT)
372 *
373 * and if that isn't true, the page has been COW'ed (in which case it
374 * _does_ have a "struct page" associated with it even if it is in a
375 * VM_PFNMAP range).
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800376 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800377struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr, pte_t pte)
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800378{
Linus Torvalds6aab3412005-11-28 14:34:23 -0800379 unsigned long pfn = pte_pfn(pte);
380
381 if (vma->vm_flags & VM_PFNMAP) {
382 unsigned long off = (addr - vma->vm_start) >> PAGE_SHIFT;
383 if (pfn == vma->vm_pgoff + off)
384 return NULL;
Linus Torvalds67121172005-12-11 20:38:17 -0800385 if (!is_cow_mapping(vma->vm_flags))
Linus Torvaldsfb155c12005-12-11 19:46:02 -0800386 return NULL;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800387 }
388
389 /*
390 * Add some anal sanity checks for now. Eventually,
391 * we should just do "return pfn_to_page(pfn)", but
392 * in the meantime we check that we get a valid pfn,
393 * and that the resulting page looks ok.
394 *
395 * Remove this test eventually!
396 */
397 if (unlikely(!pfn_valid(pfn))) {
398 print_bad_pte(vma, pte, addr);
399 return NULL;
400 }
401
402 /*
403 * NOTE! We still have PageReserved() pages in the page
404 * tables.
405 *
406 * The PAGE_ZERO() pages and various VDSO mappings can
407 * cause them to exist.
408 */
409 return pfn_to_page(pfn);
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800410}
411
412/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 * copy one vm_area from one task to the other. Assumes the page tables
414 * already present in the new task to be cleared in the whole range
415 * covered by this vma.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 */
417
Hugh Dickins8c103762005-10-29 18:16:13 -0700418static inline void
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
Nick Pigginb5810032005-10-29 18:16:12 -0700420 pte_t *dst_pte, pte_t *src_pte, struct vm_area_struct *vma,
Hugh Dickins8c103762005-10-29 18:16:13 -0700421 unsigned long addr, int *rss)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700422{
Nick Pigginb5810032005-10-29 18:16:12 -0700423 unsigned long vm_flags = vma->vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 pte_t pte = *src_pte;
425 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700426
427 /* pte contains position in swap or file, so copy. */
428 if (unlikely(!pte_present(pte))) {
429 if (!pte_file(pte)) {
430 swap_duplicate(pte_to_swp_entry(pte));
431 /* make sure dst_mm is on swapoff's mmlist. */
432 if (unlikely(list_empty(&dst_mm->mmlist))) {
433 spin_lock(&mmlist_lock);
Hugh Dickinsf412ac02005-10-29 18:16:41 -0700434 if (list_empty(&dst_mm->mmlist))
435 list_add(&dst_mm->mmlist,
436 &src_mm->mmlist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 spin_unlock(&mmlist_lock);
438 }
439 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700440 goto out_set_pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 }
442
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 /*
444 * If it's a COW mapping, write protect it both
445 * in the parent and the child
446 */
Linus Torvalds67121172005-12-11 20:38:17 -0800447 if (is_cow_mapping(vm_flags)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 ptep_set_wrprotect(src_mm, addr, src_pte);
449 pte = *src_pte;
450 }
451
452 /*
453 * If it's a shared mapping, mark it clean in
454 * the child
455 */
456 if (vm_flags & VM_SHARED)
457 pte = pte_mkclean(pte);
458 pte = pte_mkold(pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800459
460 page = vm_normal_page(vma, addr, pte);
461 if (page) {
462 get_page(page);
463 page_dup_rmap(page);
464 rss[!!PageAnon(page)]++;
465 }
Hugh Dickinsae859762005-10-29 18:16:05 -0700466
467out_set_pte:
468 set_pte_at(dst_mm, addr, dst_pte, pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469}
470
471static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
472 pmd_t *dst_pmd, pmd_t *src_pmd, struct vm_area_struct *vma,
473 unsigned long addr, unsigned long end)
474{
475 pte_t *src_pte, *dst_pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700476 spinlock_t *src_ptl, *dst_ptl;
Hugh Dickinse040f212005-10-29 18:15:53 -0700477 int progress = 0;
Hugh Dickins8c103762005-10-29 18:16:13 -0700478 int rss[2];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479
480again:
Hugh Dickinsae859762005-10-29 18:16:05 -0700481 rss[1] = rss[0] = 0;
Hugh Dickinsc74df322005-10-29 18:16:23 -0700482 dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 if (!dst_pte)
484 return -ENOMEM;
485 src_pte = pte_offset_map_nested(src_pmd, addr);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -0700486 src_ptl = pte_lockptr(src_mm, src_pmd);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700487 spin_lock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489 do {
490 /*
491 * We are holding two locks at this point - either of them
492 * could generate latencies in another task on another CPU.
493 */
Hugh Dickinse040f212005-10-29 18:15:53 -0700494 if (progress >= 32) {
495 progress = 0;
496 if (need_resched() ||
Hugh Dickinsc74df322005-10-29 18:16:23 -0700497 need_lockbreak(src_ptl) ||
498 need_lockbreak(dst_ptl))
Hugh Dickinse040f212005-10-29 18:15:53 -0700499 break;
500 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 if (pte_none(*src_pte)) {
502 progress++;
503 continue;
504 }
Hugh Dickins8c103762005-10-29 18:16:13 -0700505 copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700506 progress += 8;
507 } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508
Hugh Dickinsc74df322005-10-29 18:16:23 -0700509 spin_unlock(src_ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 pte_unmap_nested(src_pte - 1);
Hugh Dickinsae859762005-10-29 18:16:05 -0700511 add_mm_rss(dst_mm, rss[0], rss[1]);
Hugh Dickinsc74df322005-10-29 18:16:23 -0700512 pte_unmap_unlock(dst_pte - 1, dst_ptl);
513 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700514 if (addr != end)
515 goto again;
516 return 0;
517}
518
519static inline int copy_pmd_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
520 pud_t *dst_pud, pud_t *src_pud, struct vm_area_struct *vma,
521 unsigned long addr, unsigned long end)
522{
523 pmd_t *src_pmd, *dst_pmd;
524 unsigned long next;
525
526 dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
527 if (!dst_pmd)
528 return -ENOMEM;
529 src_pmd = pmd_offset(src_pud, addr);
530 do {
531 next = pmd_addr_end(addr, end);
532 if (pmd_none_or_clear_bad(src_pmd))
533 continue;
534 if (copy_pte_range(dst_mm, src_mm, dst_pmd, src_pmd,
535 vma, addr, next))
536 return -ENOMEM;
537 } while (dst_pmd++, src_pmd++, addr = next, addr != end);
538 return 0;
539}
540
541static inline int copy_pud_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
542 pgd_t *dst_pgd, pgd_t *src_pgd, struct vm_area_struct *vma,
543 unsigned long addr, unsigned long end)
544{
545 pud_t *src_pud, *dst_pud;
546 unsigned long next;
547
548 dst_pud = pud_alloc(dst_mm, dst_pgd, addr);
549 if (!dst_pud)
550 return -ENOMEM;
551 src_pud = pud_offset(src_pgd, addr);
552 do {
553 next = pud_addr_end(addr, end);
554 if (pud_none_or_clear_bad(src_pud))
555 continue;
556 if (copy_pmd_range(dst_mm, src_mm, dst_pud, src_pud,
557 vma, addr, next))
558 return -ENOMEM;
559 } while (dst_pud++, src_pud++, addr = next, addr != end);
560 return 0;
561}
562
563int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
564 struct vm_area_struct *vma)
565{
566 pgd_t *src_pgd, *dst_pgd;
567 unsigned long next;
568 unsigned long addr = vma->vm_start;
569 unsigned long end = vma->vm_end;
570
Nick Piggind9928952005-08-28 16:49:11 +1000571 /*
572 * Don't copy ptes where a page fault will fill them correctly.
573 * Fork becomes much lighter when there are big shared or private
574 * readonly mappings. The tradeoff is that copy_page_range is more
575 * efficient than faulting.
576 */
Linus Torvalds4d7672b2005-12-16 10:21:23 -0800577 if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_PFNMAP|VM_INSERTPAGE))) {
Nick Piggind9928952005-08-28 16:49:11 +1000578 if (!vma->anon_vma)
579 return 0;
580 }
581
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 if (is_vm_hugetlb_page(vma))
583 return copy_hugetlb_page_range(dst_mm, src_mm, vma);
584
585 dst_pgd = pgd_offset(dst_mm, addr);
586 src_pgd = pgd_offset(src_mm, addr);
587 do {
588 next = pgd_addr_end(addr, end);
589 if (pgd_none_or_clear_bad(src_pgd))
590 continue;
591 if (copy_pud_range(dst_mm, src_mm, dst_pgd, src_pgd,
592 vma, addr, next))
593 return -ENOMEM;
594 } while (dst_pgd++, src_pgd++, addr = next, addr != end);
595 return 0;
596}
597
Robin Holt51c6f662005-11-13 16:06:42 -0800598static unsigned long zap_pte_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700599 struct vm_area_struct *vma, pmd_t *pmd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800601 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700602{
Nick Pigginb5810032005-10-29 18:16:12 -0700603 struct mm_struct *mm = tlb->mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604 pte_t *pte;
Hugh Dickins508034a2005-10-29 18:16:30 -0700605 spinlock_t *ptl;
Hugh Dickinsae859762005-10-29 18:16:05 -0700606 int file_rss = 0;
607 int anon_rss = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
Hugh Dickins508034a2005-10-29 18:16:30 -0700609 pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 do {
611 pte_t ptent = *pte;
Robin Holt51c6f662005-11-13 16:06:42 -0800612 if (pte_none(ptent)) {
613 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800615 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616 if (pte_present(ptent)) {
Hugh Dickinsee498ed2005-11-21 21:32:18 -0800617 struct page *page;
Robin Holt51c6f662005-11-13 16:06:42 -0800618
619 (*zap_work) -= PAGE_SIZE;
620
Linus Torvalds6aab3412005-11-28 14:34:23 -0800621 page = vm_normal_page(vma, addr, ptent);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 if (unlikely(details) && page) {
623 /*
624 * unmap_shared_mapping_pages() wants to
625 * invalidate cache without truncating:
626 * unmap shared but keep private pages.
627 */
628 if (details->check_mapping &&
629 details->check_mapping != page->mapping)
630 continue;
631 /*
632 * Each page->index must be checked when
633 * invalidating or truncating nonlinear.
634 */
635 if (details->nonlinear_vma &&
636 (page->index < details->first_index ||
637 page->index > details->last_index))
638 continue;
639 }
Nick Pigginb5810032005-10-29 18:16:12 -0700640 ptent = ptep_get_and_clear_full(mm, addr, pte,
Zachary Amsdena6003882005-09-03 15:55:04 -0700641 tlb->fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700642 tlb_remove_tlb_entry(tlb, pte, addr);
643 if (unlikely(!page))
644 continue;
645 if (unlikely(details) && details->nonlinear_vma
646 && linear_page_index(details->nonlinear_vma,
647 addr) != page->index)
Nick Pigginb5810032005-10-29 18:16:12 -0700648 set_pte_at(mm, addr, pte,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 pgoff_to_pte(page->index));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 if (PageAnon(page))
Hugh Dickins86d912f2005-10-29 18:16:14 -0700651 anon_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700652 else {
653 if (pte_dirty(ptent))
654 set_page_dirty(page);
655 if (pte_young(ptent))
656 mark_page_accessed(page);
Hugh Dickins86d912f2005-10-29 18:16:14 -0700657 file_rss--;
Hugh Dickins6237bcd2005-10-29 18:15:54 -0700658 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 page_remove_rmap(page);
660 tlb_remove_page(tlb, page);
661 continue;
662 }
663 /*
664 * If details->check_mapping, we leave swap entries;
665 * if details->nonlinear_vma, we leave file entries.
666 */
667 if (unlikely(details))
668 continue;
669 if (!pte_file(ptent))
670 free_swap_and_cache(pte_to_swp_entry(ptent));
Nick Pigginb5810032005-10-29 18:16:12 -0700671 pte_clear_full(mm, addr, pte, tlb->fullmm);
Robin Holt51c6f662005-11-13 16:06:42 -0800672 } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
Hugh Dickinsae859762005-10-29 18:16:05 -0700673
Hugh Dickins86d912f2005-10-29 18:16:14 -0700674 add_mm_rss(mm, file_rss, anon_rss);
Hugh Dickins508034a2005-10-29 18:16:30 -0700675 pte_unmap_unlock(pte - 1, ptl);
Robin Holt51c6f662005-11-13 16:06:42 -0800676
677 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678}
679
Robin Holt51c6f662005-11-13 16:06:42 -0800680static inline unsigned long zap_pmd_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700681 struct vm_area_struct *vma, pud_t *pud,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700682 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800683 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684{
685 pmd_t *pmd;
686 unsigned long next;
687
688 pmd = pmd_offset(pud, addr);
689 do {
690 next = pmd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800691 if (pmd_none_or_clear_bad(pmd)) {
692 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800694 }
695 next = zap_pte_range(tlb, vma, pmd, addr, next,
696 zap_work, details);
697 } while (pmd++, addr = next, (addr != end && *zap_work > 0));
698
699 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700}
701
Robin Holt51c6f662005-11-13 16:06:42 -0800702static inline unsigned long zap_pud_range(struct mmu_gather *tlb,
Nick Pigginb5810032005-10-29 18:16:12 -0700703 struct vm_area_struct *vma, pgd_t *pgd,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800705 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700706{
707 pud_t *pud;
708 unsigned long next;
709
710 pud = pud_offset(pgd, addr);
711 do {
712 next = pud_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800713 if (pud_none_or_clear_bad(pud)) {
714 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800716 }
717 next = zap_pmd_range(tlb, vma, pud, addr, next,
718 zap_work, details);
719 } while (pud++, addr = next, (addr != end && *zap_work > 0));
720
721 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722}
723
Robin Holt51c6f662005-11-13 16:06:42 -0800724static unsigned long unmap_page_range(struct mmu_gather *tlb,
725 struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700726 unsigned long addr, unsigned long end,
Robin Holt51c6f662005-11-13 16:06:42 -0800727 long *zap_work, struct zap_details *details)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728{
729 pgd_t *pgd;
730 unsigned long next;
731
732 if (details && !details->check_mapping && !details->nonlinear_vma)
733 details = NULL;
734
735 BUG_ON(addr >= end);
736 tlb_start_vma(tlb, vma);
737 pgd = pgd_offset(vma->vm_mm, addr);
738 do {
739 next = pgd_addr_end(addr, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800740 if (pgd_none_or_clear_bad(pgd)) {
741 (*zap_work)--;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 continue;
Robin Holt51c6f662005-11-13 16:06:42 -0800743 }
744 next = zap_pud_range(tlb, vma, pgd, addr, next,
745 zap_work, details);
746 } while (pgd++, addr = next, (addr != end && *zap_work > 0));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700747 tlb_end_vma(tlb, vma);
Robin Holt51c6f662005-11-13 16:06:42 -0800748
749 return addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750}
751
752#ifdef CONFIG_PREEMPT
753# define ZAP_BLOCK_SIZE (8 * PAGE_SIZE)
754#else
755/* No preempt: go for improved straight-line efficiency */
756# define ZAP_BLOCK_SIZE (1024 * PAGE_SIZE)
757#endif
758
759/**
760 * unmap_vmas - unmap a range of memory covered by a list of vma's
761 * @tlbp: address of the caller's struct mmu_gather
Linus Torvalds1da177e2005-04-16 15:20:36 -0700762 * @vma: the starting vma
763 * @start_addr: virtual address at which to start unmapping
764 * @end_addr: virtual address at which to end unmapping
765 * @nr_accounted: Place number of unmapped pages in vm-accountable vma's here
766 * @details: details of nonlinear truncation or shared cache invalidation
767 *
Hugh Dickinsee39b372005-04-19 13:29:15 -0700768 * Returns the end address of the unmapping (restart addr if interrupted).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700770 * Unmap all pages in the vma list.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 *
Hugh Dickins508034a2005-10-29 18:16:30 -0700772 * We aim to not hold locks for too long (for scheduling latency reasons).
773 * So zap pages in ZAP_BLOCK_SIZE bytecounts. This means we need to
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 * return the ending mmu_gather to the caller.
775 *
776 * Only addresses between `start' and `end' will be unmapped.
777 *
778 * The VMA list must be sorted in ascending virtual address order.
779 *
780 * unmap_vmas() assumes that the caller will flush the whole unmapped address
781 * range after unmap_vmas() returns. So the only responsibility here is to
782 * ensure that any thus-far unmapped pages are flushed before unmap_vmas()
783 * drops the lock and schedules.
784 */
Hugh Dickins508034a2005-10-29 18:16:30 -0700785unsigned long unmap_vmas(struct mmu_gather **tlbp,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700786 struct vm_area_struct *vma, unsigned long start_addr,
787 unsigned long end_addr, unsigned long *nr_accounted,
788 struct zap_details *details)
789{
Robin Holt51c6f662005-11-13 16:06:42 -0800790 long zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700791 unsigned long tlb_start = 0; /* For tlb_finish_mmu */
792 int tlb_start_valid = 0;
Hugh Dickinsee39b372005-04-19 13:29:15 -0700793 unsigned long start = start_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700794 spinlock_t *i_mmap_lock = details? details->i_mmap_lock: NULL;
Hugh Dickins4d6ddfa2005-10-29 18:16:02 -0700795 int fullmm = (*tlbp)->fullmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796
797 for ( ; vma && vma->vm_start < end_addr; vma = vma->vm_next) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700798 unsigned long end;
799
800 start = max(vma->vm_start, start_addr);
801 if (start >= vma->vm_end)
802 continue;
803 end = min(vma->vm_end, end_addr);
804 if (end <= vma->vm_start)
805 continue;
806
807 if (vma->vm_flags & VM_ACCOUNT)
808 *nr_accounted += (end - start) >> PAGE_SHIFT;
809
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 while (start != end) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700811 if (!tlb_start_valid) {
812 tlb_start = start;
813 tlb_start_valid = 1;
814 }
815
Robin Holt51c6f662005-11-13 16:06:42 -0800816 if (unlikely(is_vm_hugetlb_page(vma))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700817 unmap_hugepage_range(vma, start, end);
Robin Holt51c6f662005-11-13 16:06:42 -0800818 zap_work -= (end - start) /
819 (HPAGE_SIZE / PAGE_SIZE);
820 start = end;
821 } else
822 start = unmap_page_range(*tlbp, vma,
823 start, end, &zap_work, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700824
Robin Holt51c6f662005-11-13 16:06:42 -0800825 if (zap_work > 0) {
826 BUG_ON(start != end);
827 break;
828 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829
830 tlb_finish_mmu(*tlbp, tlb_start, start);
831
832 if (need_resched() ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700833 (i_mmap_lock && need_lockbreak(i_mmap_lock))) {
834 if (i_mmap_lock) {
Hugh Dickins508034a2005-10-29 18:16:30 -0700835 *tlbp = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700836 goto out;
837 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839 }
840
Hugh Dickins508034a2005-10-29 18:16:30 -0700841 *tlbp = tlb_gather_mmu(vma->vm_mm, fullmm);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 tlb_start_valid = 0;
Robin Holt51c6f662005-11-13 16:06:42 -0800843 zap_work = ZAP_BLOCK_SIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 }
845 }
846out:
Hugh Dickinsee39b372005-04-19 13:29:15 -0700847 return start; /* which is now the end (or restart) address */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848}
849
850/**
851 * zap_page_range - remove user pages in a given range
852 * @vma: vm_area_struct holding the applicable pages
853 * @address: starting address of pages to zap
854 * @size: number of bytes to zap
855 * @details: details of nonlinear truncation or shared cache invalidation
856 */
Hugh Dickinsee39b372005-04-19 13:29:15 -0700857unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700858 unsigned long size, struct zap_details *details)
859{
860 struct mm_struct *mm = vma->vm_mm;
861 struct mmu_gather *tlb;
862 unsigned long end = address + size;
863 unsigned long nr_accounted = 0;
864
Linus Torvalds1da177e2005-04-16 15:20:36 -0700865 lru_add_drain();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 tlb = tlb_gather_mmu(mm, 0);
Hugh Dickins365e9c872005-10-29 18:16:18 -0700867 update_hiwater_rss(mm);
Hugh Dickins508034a2005-10-29 18:16:30 -0700868 end = unmap_vmas(&tlb, vma, address, end, &nr_accounted, details);
869 if (tlb)
870 tlb_finish_mmu(tlb, address, end);
Hugh Dickinsee39b372005-04-19 13:29:15 -0700871 return end;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700872}
873
874/*
875 * Do a quick page-table lookup for a single page.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 */
Linus Torvalds6aab3412005-11-28 14:34:23 -0800877struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700878 unsigned int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700879{
880 pgd_t *pgd;
881 pud_t *pud;
882 pmd_t *pmd;
883 pte_t *ptep, pte;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700884 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 struct page *page;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800886 struct mm_struct *mm = vma->vm_mm;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700888 page = follow_huge_addr(mm, address, flags & FOLL_WRITE);
889 if (!IS_ERR(page)) {
890 BUG_ON(flags & FOLL_GET);
891 goto out;
892 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700893
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700894 page = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 pgd = pgd_offset(mm, address);
896 if (pgd_none(*pgd) || unlikely(pgd_bad(*pgd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700897 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898
899 pud = pud_offset(pgd, address);
900 if (pud_none(*pud) || unlikely(pud_bad(*pud)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700901 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700902
903 pmd = pmd_offset(pud, address);
904 if (pmd_none(*pmd) || unlikely(pmd_bad(*pmd)))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700905 goto no_page_table;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700907 if (pmd_huge(*pmd)) {
908 BUG_ON(flags & FOLL_GET);
909 page = follow_huge_pmd(mm, address, pmd, flags & FOLL_WRITE);
910 goto out;
911 }
912
913 ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700914 if (!ptep)
915 goto out;
916
917 pte = *ptep;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700918 if (!pte_present(pte))
919 goto unlock;
920 if ((flags & FOLL_WRITE) && !pte_write(pte))
921 goto unlock;
Linus Torvalds6aab3412005-11-28 14:34:23 -0800922 page = vm_normal_page(vma, address, pte);
923 if (unlikely(!page))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700924 goto unlock;
925
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700926 if (flags & FOLL_GET)
927 get_page(page);
928 if (flags & FOLL_TOUCH) {
929 if ((flags & FOLL_WRITE) &&
930 !pte_dirty(pte) && !PageDirty(page))
931 set_page_dirty(page);
932 mark_page_accessed(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700934unlock:
935 pte_unmap_unlock(ptep, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700936out:
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700937 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700939no_page_table:
940 /*
941 * When core dumping an enormous anonymous area that nobody
942 * has touched so far, we don't want to allocate page tables.
943 */
944 if (flags & FOLL_ANON) {
945 page = ZERO_PAGE(address);
946 if (flags & FOLL_GET)
947 get_page(page);
948 BUG_ON(flags & FOLL_WRITE);
949 }
950 return page;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700951}
952
Linus Torvalds1da177e2005-04-16 15:20:36 -0700953int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
954 unsigned long start, int len, int write, int force,
955 struct page **pages, struct vm_area_struct **vmas)
956{
957 int i;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700958 unsigned int vm_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700959
960 /*
961 * Require read or write permissions.
962 * If 'force' is set, we only require the "MAY" flags.
963 */
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700964 vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
965 vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700966 i = 0;
967
968 do {
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -0700969 struct vm_area_struct *vma;
970 unsigned int foll_flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971
972 vma = find_extend_vma(mm, start);
973 if (!vma && in_gate_area(tsk, start)) {
974 unsigned long pg = start & PAGE_MASK;
975 struct vm_area_struct *gate_vma = get_gate_vma(tsk);
976 pgd_t *pgd;
977 pud_t *pud;
978 pmd_t *pmd;
979 pte_t *pte;
980 if (write) /* user gate pages are read-only */
981 return i ? : -EFAULT;
982 if (pg > TASK_SIZE)
983 pgd = pgd_offset_k(pg);
984 else
985 pgd = pgd_offset_gate(mm, pg);
986 BUG_ON(pgd_none(*pgd));
987 pud = pud_offset(pgd, pg);
988 BUG_ON(pud_none(*pud));
989 pmd = pmd_offset(pud, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700990 if (pmd_none(*pmd))
991 return i ? : -EFAULT;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992 pte = pte_offset_map(pmd, pg);
Hugh Dickins690dbe12005-08-01 21:11:42 -0700993 if (pte_none(*pte)) {
994 pte_unmap(pte);
995 return i ? : -EFAULT;
996 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700997 if (pages) {
Nick Pigginfa2a4552005-11-29 18:43:17 +1100998 struct page *page = vm_normal_page(gate_vma, start, *pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -0800999 pages[i] = page;
1000 if (page)
1001 get_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002 }
1003 pte_unmap(pte);
1004 if (vmas)
1005 vmas[i] = gate_vma;
1006 i++;
1007 start += PAGE_SIZE;
1008 len--;
1009 continue;
1010 }
1011
Linus Torvalds1ff80382005-12-12 16:24:33 -08001012 if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP))
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001013 || !(vm_flags & vma->vm_flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 return i ? : -EFAULT;
1015
1016 if (is_vm_hugetlb_page(vma)) {
1017 i = follow_hugetlb_page(mm, vma, pages, vmas,
1018 &start, &len, i);
1019 continue;
1020 }
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001021
1022 foll_flags = FOLL_TOUCH;
1023 if (pages)
1024 foll_flags |= FOLL_GET;
1025 if (!write && !(vma->vm_flags & VM_LOCKED) &&
1026 (!vma->vm_ops || !vma->vm_ops->nopage))
1027 foll_flags |= FOLL_ANON;
1028
Linus Torvalds1da177e2005-04-16 15:20:36 -07001029 do {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001030 struct page *page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001032 if (write)
1033 foll_flags |= FOLL_WRITE;
1034
1035 cond_resched();
Linus Torvalds6aab3412005-11-28 14:34:23 -08001036 while (!(page = follow_page(vma, start, foll_flags))) {
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001037 int ret;
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001038 ret = __handle_mm_fault(mm, vma, start,
1039 foll_flags & FOLL_WRITE);
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001040 /*
1041 * The VM_FAULT_WRITE bit tells us that do_wp_page has
1042 * broken COW when necessary, even if maybe_mkwrite
1043 * decided not to set pte_write. We can thus safely do
1044 * subsequent page lookups as if they were reads.
1045 */
1046 if (ret & VM_FAULT_WRITE)
Hugh Dickinsdeceb6c2005-10-29 18:16:33 -07001047 foll_flags &= ~FOLL_WRITE;
Linus Torvaldsa68d2eb2005-08-03 10:07:09 -07001048
1049 switch (ret & ~VM_FAULT_WRITE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001050 case VM_FAULT_MINOR:
1051 tsk->min_flt++;
1052 break;
1053 case VM_FAULT_MAJOR:
1054 tsk->maj_flt++;
1055 break;
1056 case VM_FAULT_SIGBUS:
1057 return i ? i : -EFAULT;
1058 case VM_FAULT_OOM:
1059 return i ? i : -ENOMEM;
1060 default:
1061 BUG();
1062 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001063 }
1064 if (pages) {
Hugh Dickins08ef4722005-06-21 17:15:10 -07001065 pages[i] = page;
1066 flush_dcache_page(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 }
1068 if (vmas)
1069 vmas[i] = vma;
1070 i++;
1071 start += PAGE_SIZE;
1072 len--;
Hugh Dickins08ef4722005-06-21 17:15:10 -07001073 } while (len && start < vma->vm_end);
Hugh Dickins08ef4722005-06-21 17:15:10 -07001074 } while (len);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001075 return i;
1076}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077EXPORT_SYMBOL(get_user_pages);
1078
1079static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1080 unsigned long addr, unsigned long end, pgprot_t prot)
1081{
1082 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001083 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001084
Hugh Dickinsc74df322005-10-29 18:16:23 -07001085 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 if (!pte)
1087 return -ENOMEM;
1088 do {
Nick Pigginb5810032005-10-29 18:16:12 -07001089 struct page *page = ZERO_PAGE(addr);
1090 pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
1091 page_cache_get(page);
1092 page_add_file_rmap(page);
1093 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001094 BUG_ON(!pte_none(*pte));
1095 set_pte_at(mm, addr, pte, zero_pte);
1096 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001097 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001098 return 0;
1099}
1100
1101static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
1102 unsigned long addr, unsigned long end, pgprot_t prot)
1103{
1104 pmd_t *pmd;
1105 unsigned long next;
1106
1107 pmd = pmd_alloc(mm, pud, addr);
1108 if (!pmd)
1109 return -ENOMEM;
1110 do {
1111 next = pmd_addr_end(addr, end);
1112 if (zeromap_pte_range(mm, pmd, addr, next, prot))
1113 return -ENOMEM;
1114 } while (pmd++, addr = next, addr != end);
1115 return 0;
1116}
1117
1118static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1119 unsigned long addr, unsigned long end, pgprot_t prot)
1120{
1121 pud_t *pud;
1122 unsigned long next;
1123
1124 pud = pud_alloc(mm, pgd, addr);
1125 if (!pud)
1126 return -ENOMEM;
1127 do {
1128 next = pud_addr_end(addr, end);
1129 if (zeromap_pmd_range(mm, pud, addr, next, prot))
1130 return -ENOMEM;
1131 } while (pud++, addr = next, addr != end);
1132 return 0;
1133}
1134
1135int zeromap_page_range(struct vm_area_struct *vma,
1136 unsigned long addr, unsigned long size, pgprot_t prot)
1137{
1138 pgd_t *pgd;
1139 unsigned long next;
1140 unsigned long end = addr + size;
1141 struct mm_struct *mm = vma->vm_mm;
1142 int err;
1143
1144 BUG_ON(addr >= end);
1145 pgd = pgd_offset(mm, addr);
1146 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001147 do {
1148 next = pgd_addr_end(addr, end);
1149 err = zeromap_pud_range(mm, pgd, addr, next, prot);
1150 if (err)
1151 break;
1152 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001153 return err;
1154}
1155
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001156pte_t * fastcall get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001157{
1158 pgd_t * pgd = pgd_offset(mm, addr);
1159 pud_t * pud = pud_alloc(mm, pgd, addr);
1160 if (pud) {
Trond Myklebust49c91fb2005-11-29 19:27:22 -05001161 pmd_t * pmd = pmd_alloc(mm, pud, addr);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001162 if (pmd)
1163 return pte_alloc_map_lock(mm, pmd, addr, ptl);
1164 }
1165 return NULL;
1166}
1167
Linus Torvalds1da177e2005-04-16 15:20:36 -07001168/*
Linus Torvalds238f58d2005-11-29 13:01:56 -08001169 * This is the old fallback for page remapping.
1170 *
1171 * For historical reasons, it only allows reserved pages. Only
1172 * old drivers should use this, and they needed to mark their
1173 * pages reserved for the old functions anyway.
1174 */
1175static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
1176{
1177 int retval;
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001178 pte_t *pte;
Linus Torvalds238f58d2005-11-29 13:01:56 -08001179 spinlock_t *ptl;
1180
1181 retval = -EINVAL;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001182 if (PageAnon(page))
Linus Torvalds238f58d2005-11-29 13:01:56 -08001183 goto out;
1184 retval = -ENOMEM;
1185 flush_dcache_page(page);
Linus Torvaldsc9cfcdd2005-11-29 14:03:14 -08001186 pte = get_locked_pte(mm, addr, &ptl);
Linus Torvalds238f58d2005-11-29 13:01:56 -08001187 if (!pte)
1188 goto out;
1189 retval = -EBUSY;
1190 if (!pte_none(*pte))
1191 goto out_unlock;
1192
1193 /* Ok, finally just insert the thing.. */
1194 get_page(page);
1195 inc_mm_counter(mm, file_rss);
1196 page_add_file_rmap(page);
1197 set_pte_at(mm, addr, pte, mk_pte(page, prot));
1198
1199 retval = 0;
1200out_unlock:
1201 pte_unmap_unlock(pte, ptl);
1202out:
1203 return retval;
1204}
1205
1206/*
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001207 * This allows drivers to insert individual pages they've allocated
1208 * into a user vma.
1209 *
1210 * The page has to be a nice clean _individual_ kernel allocation.
1211 * If you allocate a compound page, you need to have marked it as
1212 * such (__GFP_COMP), or manually just split the page up yourself
1213 * (which is mainly an issue of doing "set_page_count(page, 1)" for
1214 * each sub-page, and then freeing them one by one when you free
1215 * them rather than freeing it as a compound page).
1216 *
1217 * NOTE! Traditionally this was done with "remap_pfn_range()" which
1218 * took an arbitrary page protection parameter. This doesn't allow
1219 * that. Your vma protection will have to be set up correctly, which
1220 * means that if you want a shared writable mapping, you'd better
1221 * ask for a shared writable mapping!
1222 *
1223 * The page does not need to be reserved.
1224 */
1225int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
1226{
1227 if (addr < vma->vm_start || addr >= vma->vm_end)
1228 return -EFAULT;
1229 if (!page_count(page))
1230 return -EINVAL;
Linus Torvalds4d7672b2005-12-16 10:21:23 -08001231 vma->vm_flags |= VM_INSERTPAGE;
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001232 return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
1233}
Linus Torvaldse3c33742005-12-03 20:48:11 -08001234EXPORT_SYMBOL(vm_insert_page);
Linus Torvaldsa145dd42005-11-30 09:35:19 -08001235
1236/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001237 * maps a range of physical memory into the requested pages. the old
1238 * mappings are removed. any references to nonexistent pages results
1239 * in null mappings (currently treated as "copy-on-access")
1240 */
1241static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
1242 unsigned long addr, unsigned long end,
1243 unsigned long pfn, pgprot_t prot)
1244{
1245 pte_t *pte;
Hugh Dickinsc74df322005-10-29 18:16:23 -07001246 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247
Hugh Dickinsc74df322005-10-29 18:16:23 -07001248 pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001249 if (!pte)
1250 return -ENOMEM;
1251 do {
1252 BUG_ON(!pte_none(*pte));
Nick Pigginb5810032005-10-29 18:16:12 -07001253 set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254 pfn++;
1255 } while (pte++, addr += PAGE_SIZE, addr != end);
Hugh Dickinsc74df322005-10-29 18:16:23 -07001256 pte_unmap_unlock(pte - 1, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001257 return 0;
1258}
1259
1260static inline int remap_pmd_range(struct mm_struct *mm, pud_t *pud,
1261 unsigned long addr, unsigned long end,
1262 unsigned long pfn, pgprot_t prot)
1263{
1264 pmd_t *pmd;
1265 unsigned long next;
1266
1267 pfn -= addr >> PAGE_SHIFT;
1268 pmd = pmd_alloc(mm, pud, addr);
1269 if (!pmd)
1270 return -ENOMEM;
1271 do {
1272 next = pmd_addr_end(addr, end);
1273 if (remap_pte_range(mm, pmd, addr, next,
1274 pfn + (addr >> PAGE_SHIFT), prot))
1275 return -ENOMEM;
1276 } while (pmd++, addr = next, addr != end);
1277 return 0;
1278}
1279
1280static inline int remap_pud_range(struct mm_struct *mm, pgd_t *pgd,
1281 unsigned long addr, unsigned long end,
1282 unsigned long pfn, pgprot_t prot)
1283{
1284 pud_t *pud;
1285 unsigned long next;
1286
1287 pfn -= addr >> PAGE_SHIFT;
1288 pud = pud_alloc(mm, pgd, addr);
1289 if (!pud)
1290 return -ENOMEM;
1291 do {
1292 next = pud_addr_end(addr, end);
1293 if (remap_pmd_range(mm, pud, addr, next,
1294 pfn + (addr >> PAGE_SHIFT), prot))
1295 return -ENOMEM;
1296 } while (pud++, addr = next, addr != end);
1297 return 0;
1298}
1299
1300/* Note: this is only safe if the mm semaphore is held when called. */
1301int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
1302 unsigned long pfn, unsigned long size, pgprot_t prot)
1303{
1304 pgd_t *pgd;
1305 unsigned long next;
Hugh Dickins2d15cab2005-06-25 14:54:33 -07001306 unsigned long end = addr + PAGE_ALIGN(size);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001307 struct mm_struct *mm = vma->vm_mm;
1308 int err;
1309
1310 /*
1311 * Physically remapped pages are special. Tell the
1312 * rest of the world about it:
1313 * VM_IO tells people not to look at these pages
1314 * (accesses can have side effects).
Hugh Dickins0b14c172005-11-21 21:32:15 -08001315 * VM_RESERVED is specified all over the place, because
1316 * in 2.4 it kept swapout's vma scan off this vma; but
1317 * in 2.6 the LRU scan won't even find its pages, so this
1318 * flag means no more than count its pages in reserved_vm,
1319 * and omit it from core dump, even when VM_IO turned off.
Linus Torvalds6aab3412005-11-28 14:34:23 -08001320 * VM_PFNMAP tells the core MM that the base pages are just
1321 * raw PFN mappings, and do not have a "struct page" associated
1322 * with them.
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001323 *
1324 * There's a horrible special case to handle copy-on-write
1325 * behaviour that some programs depend on. We mark the "original"
1326 * un-COW'ed pages by matching them up with "vma->vm_pgoff".
Linus Torvalds1da177e2005-04-16 15:20:36 -07001327 */
Linus Torvalds67121172005-12-11 20:38:17 -08001328 if (is_cow_mapping(vma->vm_flags)) {
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001329 if (addr != vma->vm_start || end != vma->vm_end)
Linus Torvalds7fc7e2e2005-12-11 19:57:52 -08001330 return -EINVAL;
Linus Torvaldsfb155c12005-12-11 19:46:02 -08001331 vma->vm_pgoff = pfn;
1332 }
1333
Linus Torvalds6aab3412005-11-28 14:34:23 -08001334 vma->vm_flags |= VM_IO | VM_RESERVED | VM_PFNMAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001335
1336 BUG_ON(addr >= end);
1337 pfn -= addr >> PAGE_SHIFT;
1338 pgd = pgd_offset(mm, addr);
1339 flush_cache_range(vma, addr, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001340 do {
1341 next = pgd_addr_end(addr, end);
1342 err = remap_pud_range(mm, pgd, addr, next,
1343 pfn + (addr >> PAGE_SHIFT), prot);
1344 if (err)
1345 break;
1346 } while (pgd++, addr = next, addr != end);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347 return err;
1348}
1349EXPORT_SYMBOL(remap_pfn_range);
1350
1351/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001352 * handle_pte_fault chooses page fault handler according to an entry
1353 * which was read non-atomically. Before making any commitment, on
1354 * those architectures or configurations (e.g. i386 with PAE) which
1355 * might give a mix of unmatched parts, do_swap_page and do_file_page
1356 * must check under lock before unmapping the pte and proceeding
1357 * (but do_wp_page is only called after already making such a check;
1358 * and do_anonymous_page and do_no_page can safely check later on).
1359 */
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001360static inline int pte_unmap_same(struct mm_struct *mm, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001361 pte_t *page_table, pte_t orig_pte)
1362{
1363 int same = 1;
1364#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT)
1365 if (sizeof(pte_t) > sizeof(unsigned long)) {
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001366 spinlock_t *ptl = pte_lockptr(mm, pmd);
1367 spin_lock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001368 same = pte_same(*page_table, orig_pte);
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001369 spin_unlock(ptl);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001370 }
1371#endif
1372 pte_unmap(page_table);
1373 return same;
1374}
1375
1376/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001377 * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
1378 * servicing faults for write access. In the normal case, do always want
1379 * pte_mkwrite. But get_user_pages can cause write faults for mappings
1380 * that do not have writing enabled, when used by access_process_vm.
1381 */
1382static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
1383{
1384 if (likely(vma->vm_flags & VM_WRITE))
1385 pte = pte_mkwrite(pte);
1386 return pte;
1387}
1388
Linus Torvalds6aab3412005-11-28 14:34:23 -08001389static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
1390{
1391 /*
1392 * If the source page was a PFN mapping, we don't have
1393 * a "struct page" for it. We do a best-effort copy by
1394 * just copying from the original user address. If that
1395 * fails, we just zero-fill it. Live with it.
1396 */
1397 if (unlikely(!src)) {
1398 void *kaddr = kmap_atomic(dst, KM_USER0);
Linus Torvalds5d2a2dbbc2005-11-29 14:07:55 -08001399 void __user *uaddr = (void __user *)(va & PAGE_MASK);
1400
1401 /*
1402 * This really shouldn't fail, because the page is there
1403 * in the page tables. But it might just be unreadable,
1404 * in which case we just give up and fill the result with
1405 * zeroes.
1406 */
1407 if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
Linus Torvalds6aab3412005-11-28 14:34:23 -08001408 memset(kaddr, 0, PAGE_SIZE);
1409 kunmap_atomic(kaddr, KM_USER0);
1410 return;
1411
1412 }
1413 copy_user_highpage(dst, src, va);
1414}
1415
Linus Torvalds1da177e2005-04-16 15:20:36 -07001416/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001417 * This routine handles present pages, when users try to write
1418 * to a shared page. It is done by copying the page to a new address
1419 * and decrementing the shared-page counter for the old page.
1420 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07001421 * Note that this routine assumes that the protection checks have been
1422 * done by the caller (the low-level page fault routine in most cases).
1423 * Thus we can safely just mark it writable once we've done any necessary
1424 * COW.
1425 *
1426 * We also mark the page dirty at this point even though the page will
1427 * change only once the write actually happens. This avoids a few races,
1428 * and potentially makes it more efficient.
1429 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001430 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1431 * but allow concurrent faults), with pte both mapped and locked.
1432 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001433 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001434static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1435 unsigned long address, pte_t *page_table, pmd_t *pmd,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001436 spinlock_t *ptl, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001437{
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001438 struct page *old_page, *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 pte_t entry;
Hugh Dickins65500d22005-10-29 18:15:59 -07001440 int ret = VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001441
Linus Torvalds6aab3412005-11-28 14:34:23 -08001442 old_page = vm_normal_page(vma, address, orig_pte);
Linus Torvalds6aab3412005-11-28 14:34:23 -08001443 if (!old_page)
1444 goto gotten;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001445
Hugh Dickinsd296e9c2005-06-21 17:15:11 -07001446 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001447 int reuse = can_share_swap_page(old_page);
1448 unlock_page(old_page);
1449 if (reuse) {
Ben Collinseca35132005-11-29 11:45:26 -08001450 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001451 entry = pte_mkyoung(orig_pte);
1452 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001453 ptep_set_access_flags(vma, address, page_table, entry, 1);
1454 update_mmu_cache(vma, address, entry);
1455 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001456 ret |= VM_FAULT_WRITE;
1457 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001458 }
1459 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001460
1461 /*
1462 * Ok, we need to copy. Oh, well..
1463 */
Nick Pigginb5810032005-10-29 18:16:12 -07001464 page_cache_get(old_page);
Hugh Dickins920fc352005-11-21 21:32:17 -08001465gotten:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001466 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467
1468 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001469 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001470 if (old_page == ZERO_PAGE(address)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001471 new_page = alloc_zeroed_user_highpage(vma, address);
1472 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001473 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001474 } else {
1475 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1476 if (!new_page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001477 goto oom;
Hugh Dickinse5bbe4d2005-11-29 16:54:51 +00001478 cow_user_page(new_page, old_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001479 }
Hugh Dickins65500d22005-10-29 18:15:59 -07001480
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481 /*
1482 * Re-check the pte - we dropped the lock
1483 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001484 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins65500d22005-10-29 18:15:59 -07001485 if (likely(pte_same(*page_table, orig_pte))) {
Hugh Dickins920fc352005-11-21 21:32:17 -08001486 if (old_page) {
1487 page_remove_rmap(old_page);
1488 if (!PageAnon(old_page)) {
1489 dec_mm_counter(mm, file_rss);
1490 inc_mm_counter(mm, anon_rss);
1491 }
1492 } else
Hugh Dickins42946212005-10-29 18:16:05 -07001493 inc_mm_counter(mm, anon_rss);
Ben Collinseca35132005-11-29 11:45:26 -08001494 flush_cache_page(vma, address, pte_pfn(orig_pte));
Hugh Dickins65500d22005-10-29 18:15:59 -07001495 entry = mk_pte(new_page, vma->vm_page_prot);
1496 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
1497 ptep_establish(vma, address, page_table, entry);
1498 update_mmu_cache(vma, address, entry);
1499 lazy_mmu_prot_update(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001500 lru_cache_add_active(new_page);
1501 page_add_anon_rmap(new_page, vma, address);
1502
1503 /* Free the old page.. */
1504 new_page = old_page;
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001505 ret |= VM_FAULT_WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506 }
Hugh Dickins920fc352005-11-21 21:32:17 -08001507 if (new_page)
1508 page_cache_release(new_page);
1509 if (old_page)
1510 page_cache_release(old_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001511unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001512 pte_unmap_unlock(page_table, ptl);
Nick Pigginf33ea7f2005-08-03 20:24:01 +10001513 return ret;
Hugh Dickins65500d22005-10-29 18:15:59 -07001514oom:
Hugh Dickins920fc352005-11-21 21:32:17 -08001515 if (old_page)
1516 page_cache_release(old_page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001517 return VM_FAULT_OOM;
1518}
1519
1520/*
1521 * Helper functions for unmap_mapping_range().
1522 *
1523 * __ Notes on dropping i_mmap_lock to reduce latency while unmapping __
1524 *
1525 * We have to restart searching the prio_tree whenever we drop the lock,
1526 * since the iterator is only valid while the lock is held, and anyway
1527 * a later vma might be split and reinserted earlier while lock dropped.
1528 *
1529 * The list of nonlinear vmas could be handled more efficiently, using
1530 * a placeholder, but handle it in the same way until a need is shown.
1531 * It is important to search the prio_tree before nonlinear list: a vma
1532 * may become nonlinear and be shifted from prio_tree to nonlinear list
1533 * while the lock is dropped; but never shifted from list to prio_tree.
1534 *
1535 * In order to make forward progress despite restarting the search,
1536 * vm_truncate_count is used to mark a vma as now dealt with, so we can
1537 * quickly skip it next time around. Since the prio_tree search only
1538 * shows us those vmas affected by unmapping the range in question, we
1539 * can't efficiently keep all vmas in step with mapping->truncate_count:
1540 * so instead reset them all whenever it wraps back to 0 (then go to 1).
1541 * mapping->truncate_count and vma->vm_truncate_count are protected by
1542 * i_mmap_lock.
1543 *
1544 * In order to make forward progress despite repeatedly restarting some
Hugh Dickinsee39b372005-04-19 13:29:15 -07001545 * large vma, note the restart_addr from unmap_vmas when it breaks out:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001546 * and restart from that address when we reach that vma again. It might
1547 * have been split or merged, shrunk or extended, but never shifted: so
1548 * restart_addr remains valid so long as it remains in the vma's range.
1549 * unmap_mapping_range forces truncate_count to leap over page-aligned
1550 * values so we can save vma's restart_addr in its truncate_count field.
1551 */
1552#define is_restart_addr(truncate_count) (!((truncate_count) & ~PAGE_MASK))
1553
1554static void reset_vma_truncate_counts(struct address_space *mapping)
1555{
1556 struct vm_area_struct *vma;
1557 struct prio_tree_iter iter;
1558
1559 vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, 0, ULONG_MAX)
1560 vma->vm_truncate_count = 0;
1561 list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
1562 vma->vm_truncate_count = 0;
1563}
1564
1565static int unmap_mapping_range_vma(struct vm_area_struct *vma,
1566 unsigned long start_addr, unsigned long end_addr,
1567 struct zap_details *details)
1568{
1569 unsigned long restart_addr;
1570 int need_break;
1571
1572again:
1573 restart_addr = vma->vm_truncate_count;
1574 if (is_restart_addr(restart_addr) && start_addr < restart_addr) {
1575 start_addr = restart_addr;
1576 if (start_addr >= end_addr) {
1577 /* Top of vma has been split off since last time */
1578 vma->vm_truncate_count = details->truncate_count;
1579 return 0;
1580 }
1581 }
1582
Hugh Dickinsee39b372005-04-19 13:29:15 -07001583 restart_addr = zap_page_range(vma, start_addr,
1584 end_addr - start_addr, details);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001585 need_break = need_resched() ||
1586 need_lockbreak(details->i_mmap_lock);
1587
Hugh Dickinsee39b372005-04-19 13:29:15 -07001588 if (restart_addr >= end_addr) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001589 /* We have now completed this vma: mark it so */
1590 vma->vm_truncate_count = details->truncate_count;
1591 if (!need_break)
1592 return 0;
1593 } else {
1594 /* Note restart_addr in vma's truncate_count field */
Hugh Dickinsee39b372005-04-19 13:29:15 -07001595 vma->vm_truncate_count = restart_addr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001596 if (!need_break)
1597 goto again;
1598 }
1599
1600 spin_unlock(details->i_mmap_lock);
1601 cond_resched();
1602 spin_lock(details->i_mmap_lock);
1603 return -EINTR;
1604}
1605
1606static inline void unmap_mapping_range_tree(struct prio_tree_root *root,
1607 struct zap_details *details)
1608{
1609 struct vm_area_struct *vma;
1610 struct prio_tree_iter iter;
1611 pgoff_t vba, vea, zba, zea;
1612
1613restart:
1614 vma_prio_tree_foreach(vma, &iter, root,
1615 details->first_index, details->last_index) {
1616 /* Skip quickly over those we have already dealt with */
1617 if (vma->vm_truncate_count == details->truncate_count)
1618 continue;
1619
1620 vba = vma->vm_pgoff;
1621 vea = vba + ((vma->vm_end - vma->vm_start) >> PAGE_SHIFT) - 1;
1622 /* Assume for now that PAGE_CACHE_SHIFT == PAGE_SHIFT */
1623 zba = details->first_index;
1624 if (zba < vba)
1625 zba = vba;
1626 zea = details->last_index;
1627 if (zea > vea)
1628 zea = vea;
1629
1630 if (unmap_mapping_range_vma(vma,
1631 ((zba - vba) << PAGE_SHIFT) + vma->vm_start,
1632 ((zea - vba + 1) << PAGE_SHIFT) + vma->vm_start,
1633 details) < 0)
1634 goto restart;
1635 }
1636}
1637
1638static inline void unmap_mapping_range_list(struct list_head *head,
1639 struct zap_details *details)
1640{
1641 struct vm_area_struct *vma;
1642
1643 /*
1644 * In nonlinear VMAs there is no correspondence between virtual address
1645 * offset and file offset. So we must perform an exhaustive search
1646 * across *all* the pages in each nonlinear VMA, not just the pages
1647 * whose virtual address lies outside the file truncation point.
1648 */
1649restart:
1650 list_for_each_entry(vma, head, shared.vm_set.list) {
1651 /* Skip quickly over those we have already dealt with */
1652 if (vma->vm_truncate_count == details->truncate_count)
1653 continue;
1654 details->nonlinear_vma = vma;
1655 if (unmap_mapping_range_vma(vma, vma->vm_start,
1656 vma->vm_end, details) < 0)
1657 goto restart;
1658 }
1659}
1660
1661/**
1662 * unmap_mapping_range - unmap the portion of all mmaps
1663 * in the specified address_space corresponding to the specified
1664 * page range in the underlying file.
Martin Waitz3d410882005-06-23 22:05:21 -07001665 * @mapping: the address space containing mmaps to be unmapped.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666 * @holebegin: byte in first page to unmap, relative to the start of
1667 * the underlying file. This will be rounded down to a PAGE_SIZE
1668 * boundary. Note that this is different from vmtruncate(), which
1669 * must keep the partial page. In contrast, we must get rid of
1670 * partial pages.
1671 * @holelen: size of prospective hole in bytes. This will be rounded
1672 * up to a PAGE_SIZE boundary. A holelen of zero truncates to the
1673 * end of the file.
1674 * @even_cows: 1 when truncating a file, unmap even private COWed pages;
1675 * but 0 when invalidating pagecache, don't throw away private data.
1676 */
1677void unmap_mapping_range(struct address_space *mapping,
1678 loff_t const holebegin, loff_t const holelen, int even_cows)
1679{
1680 struct zap_details details;
1681 pgoff_t hba = holebegin >> PAGE_SHIFT;
1682 pgoff_t hlen = (holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1683
1684 /* Check for overflow. */
1685 if (sizeof(holelen) > sizeof(hlen)) {
1686 long long holeend =
1687 (holebegin + holelen + PAGE_SIZE - 1) >> PAGE_SHIFT;
1688 if (holeend & ~(long long)ULONG_MAX)
1689 hlen = ULONG_MAX - hba + 1;
1690 }
1691
1692 details.check_mapping = even_cows? NULL: mapping;
1693 details.nonlinear_vma = NULL;
1694 details.first_index = hba;
1695 details.last_index = hba + hlen - 1;
1696 if (details.last_index < details.first_index)
1697 details.last_index = ULONG_MAX;
1698 details.i_mmap_lock = &mapping->i_mmap_lock;
1699
1700 spin_lock(&mapping->i_mmap_lock);
1701
1702 /* serialize i_size write against truncate_count write */
1703 smp_wmb();
1704 /* Protect against page faults, and endless unmapping loops */
1705 mapping->truncate_count++;
1706 /*
1707 * For archs where spin_lock has inclusive semantics like ia64
1708 * this smp_mb() will prevent to read pagetable contents
1709 * before the truncate_count increment is visible to
1710 * other cpus.
1711 */
1712 smp_mb();
1713 if (unlikely(is_restart_addr(mapping->truncate_count))) {
1714 if (mapping->truncate_count == 0)
1715 reset_vma_truncate_counts(mapping);
1716 mapping->truncate_count++;
1717 }
1718 details.truncate_count = mapping->truncate_count;
1719
1720 if (unlikely(!prio_tree_empty(&mapping->i_mmap)))
1721 unmap_mapping_range_tree(&mapping->i_mmap, &details);
1722 if (unlikely(!list_empty(&mapping->i_mmap_nonlinear)))
1723 unmap_mapping_range_list(&mapping->i_mmap_nonlinear, &details);
1724 spin_unlock(&mapping->i_mmap_lock);
1725}
1726EXPORT_SYMBOL(unmap_mapping_range);
1727
1728/*
1729 * Handle all mappings that got truncated by a "truncate()"
1730 * system call.
1731 *
1732 * NOTE! We have to be ready to update the memory sharing
1733 * between the file and the memory map for a potential last
1734 * incomplete page. Ugly, but necessary.
1735 */
1736int vmtruncate(struct inode * inode, loff_t offset)
1737{
1738 struct address_space *mapping = inode->i_mapping;
1739 unsigned long limit;
1740
1741 if (inode->i_size < offset)
1742 goto do_expand;
1743 /*
1744 * truncation of in-use swapfiles is disallowed - it would cause
1745 * subsequent swapout to scribble on the now-freed blocks.
1746 */
1747 if (IS_SWAPFILE(inode))
1748 goto out_busy;
1749 i_size_write(inode, offset);
1750 unmap_mapping_range(mapping, offset + PAGE_SIZE - 1, 0, 1);
1751 truncate_inode_pages(mapping, offset);
1752 goto out_truncate;
1753
1754do_expand:
1755 limit = current->signal->rlim[RLIMIT_FSIZE].rlim_cur;
1756 if (limit != RLIM_INFINITY && offset > limit)
1757 goto out_sig;
1758 if (offset > inode->i_sb->s_maxbytes)
1759 goto out_big;
1760 i_size_write(inode, offset);
1761
1762out_truncate:
1763 if (inode->i_op && inode->i_op->truncate)
1764 inode->i_op->truncate(inode);
1765 return 0;
1766out_sig:
1767 send_sig(SIGXFSZ, current, 0);
1768out_big:
1769 return -EFBIG;
1770out_busy:
1771 return -ETXTBSY;
1772}
1773
1774EXPORT_SYMBOL(vmtruncate);
1775
1776/*
1777 * Primitive swap readahead code. We simply read an aligned block of
1778 * (1 << page_cluster) entries in the swap area. This method is chosen
1779 * because it doesn't cost us any seek time. We also make sure to queue
1780 * the 'original' request together with the readahead ones...
1781 *
1782 * This has been extended to use the NUMA policies from the mm triggering
1783 * the readahead.
1784 *
1785 * Caller must hold down_read on the vma->vm_mm if vma is not NULL.
1786 */
1787void swapin_readahead(swp_entry_t entry, unsigned long addr,struct vm_area_struct *vma)
1788{
1789#ifdef CONFIG_NUMA
1790 struct vm_area_struct *next_vma = vma ? vma->vm_next : NULL;
1791#endif
1792 int i, num;
1793 struct page *new_page;
1794 unsigned long offset;
1795
1796 /*
1797 * Get the number of handles we should do readahead io to.
1798 */
1799 num = valid_swaphandles(entry, &offset);
1800 for (i = 0; i < num; offset++, i++) {
1801 /* Ok, do the async read-ahead now */
1802 new_page = read_swap_cache_async(swp_entry(swp_type(entry),
1803 offset), vma, addr);
1804 if (!new_page)
1805 break;
1806 page_cache_release(new_page);
1807#ifdef CONFIG_NUMA
1808 /*
1809 * Find the next applicable VMA for the NUMA policy.
1810 */
1811 addr += PAGE_SIZE;
1812 if (addr == 0)
1813 vma = NULL;
1814 if (vma) {
1815 if (addr >= vma->vm_end) {
1816 vma = next_vma;
1817 next_vma = vma ? vma->vm_next : NULL;
1818 }
1819 if (vma && addr < vma->vm_start)
1820 vma = NULL;
1821 } else {
1822 if (next_vma && addr >= next_vma->vm_start) {
1823 vma = next_vma;
1824 next_vma = vma->vm_next;
1825 }
1826 }
1827#endif
1828 }
1829 lru_add_drain(); /* Push any new pages onto the LRU now */
1830}
1831
1832/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001833 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1834 * but allow concurrent faults), and pte mapped but not yet locked.
1835 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001837static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
1838 unsigned long address, pte_t *page_table, pmd_t *pmd,
1839 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001840{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001841 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842 struct page *page;
Hugh Dickins65500d22005-10-29 18:15:59 -07001843 swp_entry_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844 pte_t pte;
1845 int ret = VM_FAULT_MINOR;
1846
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001847 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001848 goto out;
Hugh Dickins65500d22005-10-29 18:15:59 -07001849
1850 entry = pte_to_swp_entry(orig_pte);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851 page = lookup_swap_cache(entry);
1852 if (!page) {
1853 swapin_readahead(entry, address, vma);
1854 page = read_swap_cache_async(entry, vma, address);
1855 if (!page) {
1856 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001857 * Back out if somebody else faulted in this pte
1858 * while we released the pte lock.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001860 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861 if (likely(pte_same(*page_table, orig_pte)))
1862 ret = VM_FAULT_OOM;
Hugh Dickins65500d22005-10-29 18:15:59 -07001863 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001864 }
1865
1866 /* Had to read the page from swap area: Major fault */
1867 ret = VM_FAULT_MAJOR;
1868 inc_page_state(pgmajfault);
1869 grab_swap_token();
1870 }
1871
1872 mark_page_accessed(page);
1873 lock_page(page);
1874
1875 /*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001876 * Back out if somebody else already faulted in this pte.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 */
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001878 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Hugh Dickins9e9bef02005-10-29 18:16:15 -07001879 if (unlikely(!pte_same(*page_table, orig_pte)))
Kirill Korotaevb8107482005-05-16 21:53:50 -07001880 goto out_nomap;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001881
1882 if (unlikely(!PageUptodate(page))) {
1883 ret = VM_FAULT_SIGBUS;
1884 goto out_nomap;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001885 }
1886
1887 /* The page isn't present yet, go ahead with the fault. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888
Hugh Dickins42946212005-10-29 18:16:05 -07001889 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890 pte = mk_pte(page, vma->vm_page_prot);
1891 if (write_access && can_share_swap_page(page)) {
1892 pte = maybe_mkwrite(pte_mkdirty(pte), vma);
1893 write_access = 0;
1894 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001895
1896 flush_icache_page(vma, page);
1897 set_pte_at(mm, address, page_table, pte);
1898 page_add_anon_rmap(page, vma, address);
1899
Hugh Dickinsc475a8a2005-06-21 17:15:12 -07001900 swap_free(entry);
1901 if (vm_swap_full())
1902 remove_exclusive_swap_page(page);
1903 unlock_page(page);
1904
Linus Torvalds1da177e2005-04-16 15:20:36 -07001905 if (write_access) {
1906 if (do_wp_page(mm, vma, address,
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001907 page_table, pmd, ptl, pte) == VM_FAULT_OOM)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 ret = VM_FAULT_OOM;
1909 goto out;
1910 }
1911
1912 /* No need to invalidate - it was non-present before */
1913 update_mmu_cache(vma, address, pte);
1914 lazy_mmu_prot_update(pte);
Hugh Dickins65500d22005-10-29 18:15:59 -07001915unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001916 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001917out:
1918 return ret;
Kirill Korotaevb8107482005-05-16 21:53:50 -07001919out_nomap:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001920 pte_unmap_unlock(page_table, ptl);
Kirill Korotaevb8107482005-05-16 21:53:50 -07001921 unlock_page(page);
1922 page_cache_release(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001923 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924}
1925
1926/*
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001927 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1928 * but allow concurrent faults), and pte mapped but not yet locked.
1929 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001930 */
Hugh Dickins65500d22005-10-29 18:15:59 -07001931static int do_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
1932 unsigned long address, pte_t *page_table, pmd_t *pmd,
1933 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001934{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001935 struct page *page;
1936 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001937 pte_t entry;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001938
Linus Torvalds6aab3412005-11-28 14:34:23 -08001939 if (write_access) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940 /* Allocate our own private page. */
1941 pte_unmap(page_table);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001942
1943 if (unlikely(anon_vma_prepare(vma)))
Hugh Dickins65500d22005-10-29 18:15:59 -07001944 goto oom;
1945 page = alloc_zeroed_user_highpage(vma, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001946 if (!page)
Hugh Dickins65500d22005-10-29 18:15:59 -07001947 goto oom;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948
Hugh Dickins65500d22005-10-29 18:15:59 -07001949 entry = mk_pte(page, vma->vm_page_prot);
1950 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001951
1952 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1953 if (!pte_none(*page_table))
1954 goto release;
1955 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 lru_cache_add_active(page);
1957 SetPageReferenced(page);
Hugh Dickins65500d22005-10-29 18:15:59 -07001958 page_add_anon_rmap(page, vma, address);
Nick Pigginb5810032005-10-29 18:16:12 -07001959 } else {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001960 /* Map the ZERO_PAGE - vm_page_prot is readonly */
1961 page = ZERO_PAGE(address);
1962 page_cache_get(page);
1963 entry = mk_pte(page, vma->vm_page_prot);
1964
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07001965 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001966 spin_lock(ptl);
1967 if (!pte_none(*page_table))
1968 goto release;
Nick Pigginb5810032005-10-29 18:16:12 -07001969 inc_mm_counter(mm, file_rss);
1970 page_add_file_rmap(page);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001971 }
1972
Hugh Dickins65500d22005-10-29 18:15:59 -07001973 set_pte_at(mm, address, page_table, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974
1975 /* No need to invalidate - it was non-present before */
Hugh Dickins65500d22005-10-29 18:15:59 -07001976 update_mmu_cache(vma, address, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001977 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07001978unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001979 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001980 return VM_FAULT_MINOR;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001981release:
1982 page_cache_release(page);
1983 goto unlock;
Hugh Dickins65500d22005-10-29 18:15:59 -07001984oom:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001985 return VM_FAULT_OOM;
1986}
1987
1988/*
1989 * do_no_page() tries to create a new page mapping. It aggressively
1990 * tries to share with existing pages, but makes a separate copy if
1991 * the "write_access" parameter is true in order to avoid the next
1992 * page fault.
1993 *
1994 * As this is called only for pages that do not currently exist, we
1995 * do not need to flush old virtual caches or the TLB.
1996 *
Hugh Dickins8f4e2102005-10-29 18:16:26 -07001997 * We enter with non-exclusive mmap_sem (to exclude vma changes,
1998 * but allow concurrent faults), and pte mapped but not yet locked.
1999 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002000 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002001static int do_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
2002 unsigned long address, pte_t *page_table, pmd_t *pmd,
2003 int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004{
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002005 spinlock_t *ptl;
Hugh Dickins65500d22005-10-29 18:15:59 -07002006 struct page *new_page;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002007 struct address_space *mapping = NULL;
2008 pte_t entry;
2009 unsigned int sequence = 0;
2010 int ret = VM_FAULT_MINOR;
2011 int anon = 0;
2012
Linus Torvalds1da177e2005-04-16 15:20:36 -07002013 pte_unmap(page_table);
Hugh Dickins325f04d2005-11-29 16:55:48 +00002014 BUG_ON(vma->vm_flags & VM_PFNMAP);
2015
Linus Torvalds1da177e2005-04-16 15:20:36 -07002016 if (vma->vm_file) {
2017 mapping = vma->vm_file->f_mapping;
2018 sequence = mapping->truncate_count;
2019 smp_rmb(); /* serializes i_size against truncate_count */
2020 }
2021retry:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002022 new_page = vma->vm_ops->nopage(vma, address & PAGE_MASK, &ret);
2023 /*
2024 * No smp_rmb is needed here as long as there's a full
2025 * spin_lock/unlock sequence inside the ->nopage callback
2026 * (for the pagecache lookup) that acts as an implicit
2027 * smp_mb() and prevents the i_size read to happen
2028 * after the next truncate_count read.
2029 */
2030
2031 /* no page was available -- either SIGBUS or OOM */
2032 if (new_page == NOPAGE_SIGBUS)
2033 return VM_FAULT_SIGBUS;
2034 if (new_page == NOPAGE_OOM)
2035 return VM_FAULT_OOM;
2036
2037 /*
2038 * Should we do an early C-O-W break?
2039 */
2040 if (write_access && !(vma->vm_flags & VM_SHARED)) {
2041 struct page *page;
2042
2043 if (unlikely(anon_vma_prepare(vma)))
2044 goto oom;
2045 page = alloc_page_vma(GFP_HIGHUSER, vma, address);
2046 if (!page)
2047 goto oom;
Hugh Dickins325f04d2005-11-29 16:55:48 +00002048 copy_user_highpage(page, new_page, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002049 page_cache_release(new_page);
2050 new_page = page;
2051 anon = 1;
2052 }
2053
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002054 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002055 /*
2056 * For a file-backed vma, someone could have truncated or otherwise
2057 * invalidated this page. If unmap_mapping_range got called,
2058 * retry getting the page.
2059 */
2060 if (mapping && unlikely(sequence != mapping->truncate_count)) {
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002061 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002062 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002063 cond_resched();
2064 sequence = mapping->truncate_count;
2065 smp_rmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002066 goto retry;
2067 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002068
2069 /*
2070 * This silly early PAGE_DIRTY setting removes a race
2071 * due to the bad i386 page protection. But it's valid
2072 * for other architectures too.
2073 *
2074 * Note that if write_access is true, we either now have
2075 * an exclusive copy of the page, or this is a shared mapping,
2076 * so we can make it writable and dirty to avoid having to
2077 * handle that later.
2078 */
2079 /* Only go through if we didn't race with anybody else... */
2080 if (pte_none(*page_table)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002081 flush_icache_page(vma, new_page);
2082 entry = mk_pte(new_page, vma->vm_page_prot);
2083 if (write_access)
2084 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
2085 set_pte_at(mm, address, page_table, entry);
2086 if (anon) {
Hugh Dickins42946212005-10-29 18:16:05 -07002087 inc_mm_counter(mm, anon_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002088 lru_cache_add_active(new_page);
2089 page_add_anon_rmap(new_page, vma, address);
Hugh Dickinsf57e88a2005-11-21 21:32:19 -08002090 } else {
Hugh Dickins42946212005-10-29 18:16:05 -07002091 inc_mm_counter(mm, file_rss);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002092 page_add_file_rmap(new_page);
Hugh Dickins42946212005-10-29 18:16:05 -07002093 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002094 } else {
2095 /* One of our sibling threads was faster, back out. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002097 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002098 }
2099
2100 /* no need to invalidate: a not-present page shouldn't be cached */
2101 update_mmu_cache(vma, address, entry);
2102 lazy_mmu_prot_update(entry);
Hugh Dickins65500d22005-10-29 18:15:59 -07002103unlock:
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002104 pte_unmap_unlock(page_table, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002105 return ret;
2106oom:
2107 page_cache_release(new_page);
Hugh Dickins65500d22005-10-29 18:15:59 -07002108 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109}
2110
2111/*
2112 * Fault of a previously existing named mapping. Repopulate the pte
2113 * from the encoded file_pte if possible. This enables swappable
2114 * nonlinear vmas.
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002115 *
2116 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2117 * but allow concurrent faults), and pte mapped but not yet locked.
2118 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002119 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002120static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
2121 unsigned long address, pte_t *page_table, pmd_t *pmd,
2122 int write_access, pte_t orig_pte)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002123{
Hugh Dickins65500d22005-10-29 18:15:59 -07002124 pgoff_t pgoff;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 int err;
2126
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002127 if (!pte_unmap_same(mm, pmd, page_table, orig_pte))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002128 return VM_FAULT_MINOR;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002129
Hugh Dickins65500d22005-10-29 18:15:59 -07002130 if (unlikely(!(vma->vm_flags & VM_NONLINEAR))) {
2131 /*
2132 * Page table corrupted: show pte and kill process.
2133 */
Nick Pigginb5810032005-10-29 18:16:12 -07002134 print_bad_pte(vma, orig_pte, address);
Hugh Dickins65500d22005-10-29 18:15:59 -07002135 return VM_FAULT_OOM;
2136 }
2137 /* We can then assume vm->vm_ops && vma->vm_ops->populate */
2138
2139 pgoff = pte_to_pgoff(orig_pte);
2140 err = vma->vm_ops->populate(vma, address & PAGE_MASK, PAGE_SIZE,
2141 vma->vm_page_prot, pgoff, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002142 if (err == -ENOMEM)
2143 return VM_FAULT_OOM;
2144 if (err)
2145 return VM_FAULT_SIGBUS;
2146 return VM_FAULT_MAJOR;
2147}
2148
2149/*
2150 * These routines also need to handle stuff like marking pages dirty
2151 * and/or accessed for architectures that don't do it in hardware (most
2152 * RISC architectures). The early dirtying is also good on the i386.
2153 *
2154 * There is also a hook called "update_mmu_cache()" that architectures
2155 * with external mmu caches can use to update those (ie the Sparc or
2156 * PowerPC hashed page tables that act as extended TLBs).
2157 *
Hugh Dickinsc74df322005-10-29 18:16:23 -07002158 * We enter with non-exclusive mmap_sem (to exclude vma changes,
2159 * but allow concurrent faults), and pte mapped but not yet locked.
2160 * We return with mmap_sem still held, but pte unmapped and unlocked.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002161 */
2162static inline int handle_pte_fault(struct mm_struct *mm,
Hugh Dickins65500d22005-10-29 18:15:59 -07002163 struct vm_area_struct *vma, unsigned long address,
2164 pte_t *pte, pmd_t *pmd, int write_access)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165{
2166 pte_t entry;
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002167 pte_t old_entry;
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002168 spinlock_t *ptl;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002170 old_entry = entry = *pte;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002171 if (!pte_present(entry)) {
Hugh Dickins65500d22005-10-29 18:15:59 -07002172 if (pte_none(entry)) {
2173 if (!vma->vm_ops || !vma->vm_ops->nopage)
2174 return do_anonymous_page(mm, vma, address,
2175 pte, pmd, write_access);
2176 return do_no_page(mm, vma, address,
2177 pte, pmd, write_access);
2178 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002179 if (pte_file(entry))
Hugh Dickins65500d22005-10-29 18:15:59 -07002180 return do_file_page(mm, vma, address,
2181 pte, pmd, write_access, entry);
2182 return do_swap_page(mm, vma, address,
2183 pte, pmd, write_access, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184 }
2185
Hugh Dickins4c21e2f2005-10-29 18:16:40 -07002186 ptl = pte_lockptr(mm, pmd);
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002187 spin_lock(ptl);
2188 if (unlikely(!pte_same(*pte, entry)))
2189 goto unlock;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002190 if (write_access) {
2191 if (!pte_write(entry))
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002192 return do_wp_page(mm, vma, address,
2193 pte, pmd, ptl, entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002194 entry = pte_mkdirty(entry);
2195 }
2196 entry = pte_mkyoung(entry);
Andrea Arcangeli1a44e142005-10-29 18:16:48 -07002197 if (!pte_same(old_entry, entry)) {
2198 ptep_set_access_flags(vma, address, pte, entry, write_access);
2199 update_mmu_cache(vma, address, entry);
2200 lazy_mmu_prot_update(entry);
2201 } else {
2202 /*
2203 * This is needed only for protection faults but the arch code
2204 * is not yet telling us if this is a protection fault or not.
2205 * This still avoids useless tlb flushes for .text page faults
2206 * with threads.
2207 */
2208 if (write_access)
2209 flush_tlb_page(vma, address);
2210 }
Hugh Dickins8f4e2102005-10-29 18:16:26 -07002211unlock:
2212 pte_unmap_unlock(pte, ptl);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 return VM_FAULT_MINOR;
2214}
2215
2216/*
2217 * By the time we get here, we already hold the mm semaphore
2218 */
Hugh Dickins65500d22005-10-29 18:15:59 -07002219int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
Linus Torvalds1da177e2005-04-16 15:20:36 -07002220 unsigned long address, int write_access)
2221{
2222 pgd_t *pgd;
2223 pud_t *pud;
2224 pmd_t *pmd;
2225 pte_t *pte;
2226
2227 __set_current_state(TASK_RUNNING);
2228
2229 inc_page_state(pgfault);
2230
Hugh Dickinsac9b9c62005-10-20 16:24:28 +01002231 if (unlikely(is_vm_hugetlb_page(vma)))
2232 return hugetlb_fault(mm, vma, address, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002233
Linus Torvalds1da177e2005-04-16 15:20:36 -07002234 pgd = pgd_offset(mm, address);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002235 pud = pud_alloc(mm, pgd, address);
2236 if (!pud)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002237 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002238 pmd = pmd_alloc(mm, pud, address);
2239 if (!pmd)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002240 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002241 pte = pte_alloc_map(mm, pmd, address);
2242 if (!pte)
Hugh Dickinsc74df322005-10-29 18:16:23 -07002243 return VM_FAULT_OOM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244
Hugh Dickinsc74df322005-10-29 18:16:23 -07002245 return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002246}
2247
2248#ifndef __PAGETABLE_PUD_FOLDED
2249/*
2250 * Allocate page upper directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002251 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002252 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002253int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002254{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002255 pud_t *new = pud_alloc_one(mm, address);
2256 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002257 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002258
Hugh Dickins872fec12005-10-29 18:16:21 -07002259 spin_lock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002260 if (pgd_present(*pgd)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002261 pud_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002262 else
2263 pgd_populate(mm, pgd, new);
Hugh Dickinsc74df322005-10-29 18:16:23 -07002264 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002265 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002266}
Alan Sterne0f39592005-11-28 13:43:44 -08002267#else
2268/* Workaround for gcc 2.96 */
2269int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
2270{
2271 return 0;
2272}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002273#endif /* __PAGETABLE_PUD_FOLDED */
2274
2275#ifndef __PAGETABLE_PMD_FOLDED
2276/*
2277 * Allocate page middle directory.
Hugh Dickins872fec12005-10-29 18:16:21 -07002278 * We've already handled the fast-path in-line.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002279 */
Hugh Dickins1bb36302005-10-29 18:16:22 -07002280int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002281{
Hugh Dickinsc74df322005-10-29 18:16:23 -07002282 pmd_t *new = pmd_alloc_one(mm, address);
2283 if (!new)
Hugh Dickins1bb36302005-10-29 18:16:22 -07002284 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002285
Hugh Dickins872fec12005-10-29 18:16:21 -07002286 spin_lock(&mm->page_table_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002287#ifndef __ARCH_HAS_4LEVEL_HACK
Hugh Dickins1bb36302005-10-29 18:16:22 -07002288 if (pud_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002290 else
2291 pud_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002292#else
Hugh Dickins1bb36302005-10-29 18:16:22 -07002293 if (pgd_present(*pud)) /* Another has populated it */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294 pmd_free(new);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002295 else
2296 pgd_populate(mm, pud, new);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002297#endif /* __ARCH_HAS_4LEVEL_HACK */
Hugh Dickinsc74df322005-10-29 18:16:23 -07002298 spin_unlock(&mm->page_table_lock);
Hugh Dickins1bb36302005-10-29 18:16:22 -07002299 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002300}
Alan Sterne0f39592005-11-28 13:43:44 -08002301#else
2302/* Workaround for gcc 2.96 */
2303int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
2304{
2305 return 0;
2306}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002307#endif /* __PAGETABLE_PMD_FOLDED */
2308
2309int make_pages_present(unsigned long addr, unsigned long end)
2310{
2311 int ret, len, write;
2312 struct vm_area_struct * vma;
2313
2314 vma = find_vma(current->mm, addr);
2315 if (!vma)
2316 return -1;
2317 write = (vma->vm_flags & VM_WRITE) != 0;
2318 if (addr >= end)
2319 BUG();
2320 if (end > vma->vm_end)
2321 BUG();
2322 len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
2323 ret = get_user_pages(current, current->mm, addr,
2324 len, write, 0, NULL, NULL);
2325 if (ret < 0)
2326 return ret;
2327 return ret == len ? 0 : -1;
2328}
2329
2330/*
2331 * Map a vmalloc()-space virtual address to the physical page.
2332 */
2333struct page * vmalloc_to_page(void * vmalloc_addr)
2334{
2335 unsigned long addr = (unsigned long) vmalloc_addr;
2336 struct page *page = NULL;
2337 pgd_t *pgd = pgd_offset_k(addr);
2338 pud_t *pud;
2339 pmd_t *pmd;
2340 pte_t *ptep, pte;
2341
2342 if (!pgd_none(*pgd)) {
2343 pud = pud_offset(pgd, addr);
2344 if (!pud_none(*pud)) {
2345 pmd = pmd_offset(pud, addr);
2346 if (!pmd_none(*pmd)) {
2347 ptep = pte_offset_map(pmd, addr);
2348 pte = *ptep;
2349 if (pte_present(pte))
2350 page = pte_page(pte);
2351 pte_unmap(ptep);
2352 }
2353 }
2354 }
2355 return page;
2356}
2357
2358EXPORT_SYMBOL(vmalloc_to_page);
2359
2360/*
2361 * Map a vmalloc()-space virtual address to the physical page frame number.
2362 */
2363unsigned long vmalloc_to_pfn(void * vmalloc_addr)
2364{
2365 return page_to_pfn(vmalloc_to_page(vmalloc_addr));
2366}
2367
2368EXPORT_SYMBOL(vmalloc_to_pfn);
2369
Linus Torvalds1da177e2005-04-16 15:20:36 -07002370#if !defined(__HAVE_ARCH_GATE_AREA)
2371
2372#if defined(AT_SYSINFO_EHDR)
Adrian Bunk5ce78522005-09-10 00:26:28 -07002373static struct vm_area_struct gate_vma;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374
2375static int __init gate_vma_init(void)
2376{
2377 gate_vma.vm_mm = NULL;
2378 gate_vma.vm_start = FIXADDR_USER_START;
2379 gate_vma.vm_end = FIXADDR_USER_END;
2380 gate_vma.vm_page_prot = PAGE_READONLY;
Hugh Dickins0b14c172005-11-21 21:32:15 -08002381 gate_vma.vm_flags = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002382 return 0;
2383}
2384__initcall(gate_vma_init);
2385#endif
2386
2387struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
2388{
2389#ifdef AT_SYSINFO_EHDR
2390 return &gate_vma;
2391#else
2392 return NULL;
2393#endif
2394}
2395
2396int in_gate_area_no_task(unsigned long addr)
2397{
2398#ifdef AT_SYSINFO_EHDR
2399 if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
2400 return 1;
2401#endif
2402 return 0;
2403}
2404
2405#endif /* __HAVE_ARCH_GATE_AREA */